Table of contents

The 7th Conference of the Sustainable Solutions for Energy and Environment, EENVIRO 2020, October 21-23, 2020

In order to meet the health and safety needs of our attendees and staff, the 7th Conference of the Sustainable Solutions for Energy and Environment (EENVIRO 2020) which was scheduled to be held in Bucharest, Romania, European Union was held virtually online during October 21-23, 2020. Being different from the traditional gatherings we all know, this virtual conference allows us to connect in new ways while keeping expenditure saving and maintaining social distancing. Presentations of presenter from different countries were accessible to hundreds of researchers effectively.

This was the original message posted on the conference website: "Since the pandemic has worsened in Romania as well as worldwide and we cannot be certain when the entry restrictions for all incoming travelers to Romania will be lifted, or when the conditions will improve, the EENVIRO 2020 organizing committee has decided to cancel the onsite conference and to hold the conference online only."

At the conference time, 21-23rd October 2020, Bucharest city, the Romania capital (the original conference location) was Covid red code. This meant that no gathering of more than 10 persons were allowed. A lot of countries from which we have participants at EENVIRO Conference were at that moment under travel restrictions to Europe Union (Australia, China, Russia, Canada, etc) or under travel restrictions (2 weeks of quarantine) for the travelers from European Union to Romania.

The organizers took into account the possibility of postponing the conference for 2021 but this was not a solution in this case due to various reasons. We issued a questionnaire for the potential participants and the reasons presented by them to organize an online conference were very strong. For example, in the frame of the conference some of the participants had some workshops dedicated to present the results from various research grants on different topics. These researchers were pressed to present the results in 2020 in the frame of their research grants. Other participants wanted to meet in the frame of the conference to propose new research topics to work on. Also, according to our authorities we did not have an answer to the question "When the conference could be organized in the near future?". Also, the organizers talked with other conference organizers worldwide like indoorair2020.org and they did the same thing as organizing the online conference mostly due to the same reasons. Almost all the participants answered that they prefer that the EENVIRO 2020 conference to be hold online.

List of titles EENVIRO 2020 Organizing Committee, Organizing Committee, Scientific committee are available in this Pdf.

All papers published in this volume of IOP Conference Series: Earth and Environmental Science have been peer reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

• Type of peer review: Double-blind

• Conference submission management system: https://easychair.org/

• Number of submissions received: 132

• Number of submissions sent for review: 125

• Number of submissions accepted: 116

• Acceptance Rate (Number of Submissions Accepted / Number of Submissions Received X 100): 87.88%

• Average number of reviews per paper: 2.21

• Total number of reviewers involved: 86

• Any additional info on review process: The review process was carried out by expert referees in their activity. All the papers were verified by a committee to be sure that they complied with the reviewers observations and if there were inconsistencies the papers were sent back to their authors. We can say that for some papers we needed three rounds of review for complying.

• Contact person for queries:

Name: Florin BODE

Affiliation: Technical University of Cluj-Napoca, Romania

Email: florin.bode@termo.utcluj.ro

We study the impact of a liquid jet on a liquid bath in the presence of an external Newtonian liquid. Attention is given to the impact zone where we find a stationary wave-like behavior of the liquid column. We unravel new dynamics, seen at high acquisition frame rates, of the instability of the liquid column at the critical distance between the capillary tip and the surface of the fluid bath. A dominant critical frequency of oscillation is found. Particle Image Velocimetry measurements of the velocity field, in the vicinity of the impact zone, are also performed, with emphasis on the vortex structure that develops near the flat interface.

We study the dynamics of capillary rise of a liquid-liquid interface using two immiscible liquids. By adjusting the height of the less dense fluid column, we measure the rise of the ensemble in the tube. A theoretical model is proposed that captures the time dependence of the position of the interface. Particular attention is given to the dynamics of the oil-water interface. Different types of flow regimes are identified and compared with previous theoretical and experimental findings. The theoretical model was found to be in good qualitative agreement, even though the contact angles of the two interfaces do not remain constant during the elevation of the fluid.

One of the largest family of complex materials are represented by fluids with yield stress. In this category are included creams, pastes, greases, gels, in general materials which start to flow at a certain value of the imposed shear stress. A common characteristic of yield stress materials is the association of material instability with the onset of the fluid behavior. The present paper is concerned with the experimental investigations and numerical modeling of the dynamics of a yield stress fluid jet in air or immersed in viscous/viscoelastic liquids. A cream jet at constant flow rate is generated through a capillary with a syringe pump and the visualizations of its motion in a vessel filled with an immiscible fluid is performed with normal and high-speed cameras. One goal of the study is to test the capability of the VoF code to simulate the jetting phenomena, the rheology of the sample being modeled with the Carreau equation and the Herschel-Bulkley relation, respectively. The visualizations show the specific yield stress instabilities from jetting to coiling, buckling and fracture.

The paper makes an analyse regarding the implications of "Eco - Design" Directive over conception and performances of small boilers. The study is based over a large number of tested boilers under certified conditions. There are mainly two families of condensing boilers: those projected from the beginning as condensing boilers and those who initially were non-condensing boilers and then were shifted to condensing functioning. The study compares the technical performances reached by the boilers of each family considering also the economical and engineering constraints implied.

Carbon dioxide footprint reduction can be reached by switching fossile combustible consumers to biogenic fuels. Using biogenic fuels, mainly cellulosic ones, requires burner replacement and most often a complete change of burning process by introducing pre-burning chambers. The boiler response is also to be studied because the changes in flue gases composition, debits and temperatures. The paper analyses the necessary burning installation retrofitting for the case of switching a local boiler from gaseous fuel functioning to cellulosic fuel functioning (sawdust or pellets). It is presented a calculation method for boiler functioning verification (determining the functioning parameters considering an existing boiler used in other than nominal conditions) with the aim of determining the parametrical and performances variations when using other fuels. The nominal functioning regime, for witch there are available experimental data, is used to validate the model and the computational program. Conclusions are drawn regarding the possibility and results for retrofitting regional heating boilers from gaseous to biogenic fuels.

The present study deals with experimental measurements of CO₂ generation rates, due to the human occupation of a full-scale experimental mock-up simulating the astronaut crew quarters aboard the International Space Station. The estimation of CO₂ generation rates follows different methods as described in the literature. A single test subject in four different testing cases is considered, one at rest representing the baseline case and the other three cases at varying levels of physical activity or at rest but with a fixed breathing frequency requested from the human subject. The study results indicate that imposing a fixed breathing rate even while at rest increases the generation rate unpredictably. Following literature metabolic rate estimations, the latter two cases are equivalent to the subject being engaged in light or medium physical activities. The results are used to form recommendations for studies measuring human CO₂ generation rates.

The study is performed on a glazed transpired solar collector, investigating the effect of different distances between the glazing and the absorber (30, 50, 70, and 100 mm) for different airflow values. The results show that the best solution among the tested configurations is with 30 mm distance between the glazing and absorber, no matter what the air flow rate is. The efficiency of the GTC in this case is 16-19% higher for air flow rates around 100 m3/h, m2 and even 30-40% higher for air flow rates around 150-200 m3/h, m2 – compared to configurations with larger distance between the glazing and absorber.

The numerical study is performed on a glazed transpired solar collector, investigating the effect of different distances between the glazing and the absorber (30 and 50 mm) for different airflow rates. The results show that the best solution among the tested configurations is using the 30 mm distance between the glazing and absorber, no matter what the air flow rate is. The efficiency of the glazed transpired solar collector (GTC) in this case is between 50%-61% for the range of airflow rates studied and higher with around 15% compared to configurations with larger distance between the glazing and absorber. The purpose of this study is to prove the efficiency increase due to pass-through elements disposals complementary with the passive components implementation, underlining the benefit of passive solar systems.

Together with the modern urbanization development, the number of underground cars parkings has grown significantly. They are provided with ventilation systems to evacuate the cars emissions and with smoke exhaust systems which intervene in case of fire. Generally, the same exhaust system is used to evacuate the emissions and the smoke from a potential fire even if the working parameters are not the same for both scenarios. The paper deals with a case study regarding an underground parking designed for 15 cars. Numerical simulations using CFD tools have been performed to establish the CO concentrations. The results prove that the CO concentration limits are exceeded due to the positioning of the exhaust grills. In case of a fire, the temperatures are still high. The conclusion is that CFD simulations are needed for this type of ventilating systems design and that only following the regulation prescriptions is not enough in case of fires.

The paper focuses on the investigation of the potential environmental impact related to the production of several types of bituminous mixtures containing different dosages of Reclaimed Asphalt Pavement (RAP) and Rejuvenator (Rej). All materials used in the presented study are specific and generally used for pavements in Romania. The RAP material was considered as an inert material and it was used in three dosages (25%, 50% and 75%). For the bituminous mixture produced with 50% RAP material, a rejuvenator consisting in a mixture of vegetal oils was used in three dosages of 0.2%, 0.4% and 0.6% by mass of RAP material. A total of seven types of bituminous mixtures were considered including one 'conventional' mixture produced with virgin materials and used as reference. The Environmental Impact Assessment was estimated for the production process of the analysed bituminous mixtures, by using Eco-indicator 99 method within SimaPro software. The results prove that the addition of RAP material leads to a net decrease of the energy use and environmental impact. Besides, when rejuvenators are used in this process, they can affect the energy balance and reduce the difference in environmental impact.

The current paper presents the optimal ways for choosing appropriate devices in order to protect the pressurized hydraulic installations in a water supply system, against water hammer phenomena. The case study done it in this research paper presents a hydraulic system formed by a main water pipe, and it's behaviour regarding the water hammer phenomena, taking into account 3 types of pipe execution materials (ductile iron, polyethylene and glass reinforced pipe). The study includes also the protection equipment's need it for each type of pipe material. Hydraulic simulation was made using a numerical calculation model, designed with a software special for non-steady flowing state in pressurized systems, called Bentley Hammer v.10i..

The aim of this article is to present a comprehensive review of the state of the art regarding the use of the human thermophysiological model into computational fluid dynamics and the coupling of these two techniques. This article will focus on the modelling of the car cabin thermal environment, the integration of virtual thermal manikins and the thermal comfort assessment. Though the complexity of the car cabin geometry, the inhomogeneous air temperature/velocity fields, and transient conditions a CFD-simulation is a very powerful tool providing detailed results for a given sufficient computing power. Understanding the human body's thermal aspects and quantifying cabin's parameters are essential for a reliable computation. Virtual thermal manikins have become an important asset in numerical simulation, providing accurate predictions of human thermal sensation. For vehicular thermal comfort assessment, this article reviews the relevant thermal comfort indices. From 70's, several human thermophysiological models have been developed based on the human energy balance equation to achieve realistic human thermal responses. This article introduces the most common human thermophysiological models classifies them into one-node, two-node, multi-node and multi-element thermal models. Today, in automotive R&D, the coupling technique is became a powerful tool for optimizing and evaluating the passenger's thermal comfort.

For the assessment of the quality and behavior of building materials in the case of fire, standard testing methods which classify these products based on their performance have been developed. This testing covers among other parameters the smoke emission of the materials in case of fire. The testing methods require various quantities of the products in order to provide accurate results, hence they can rarely be used in the research and development phase of a product. Standard tests that are used to classify building materials, usually employ the principle of light intensity attenuation for the determination of information regarding the smoke emission of the product. This paper presents the 1:10 and 1:20 scale reduction of an experiment used to determine the optical properties of artificially generated smoke based on the same principle of light attenuation. The scale reduction was carried out by means of proportionally reducing each of the test compartment dimensions and the amount of smoke fluid used. For the assessment of the scale reduction accuracy, the extinction area of smoke, which is a parameter that can correlate the light intensity values measured in the different experimental scales was used as a benchmark.

The paper is dedicated to experimental and numerical investigations of the dynamics of 3D-flow around a cylinder with 10 mm diameter. The cylinder is positioned in a confined geometry represented by a long straight channel with 50 mm width and 10 mm height. The study analyses the dependence on the Re-number of the path lines distributions in the vicinity of the immersed cylinder. The visualized flow patterns are fairly reproduced by the numerical solutions of the Navier-Stokes equations up to Re = 1000. The velocity and wall stresses are computed in the vicinity of the cylinder. One main goal of the present work is established by the correlation between the flow pattern, wake boundary and wall shear stress distributions down-stream the cylinder.

The paper is concerned with experimental studies and numerical modelling of the air flow around blunt bodies (cylinder, aerodynamic profile) inside a wind tunnel. The range of the investigated Reynolds numbers is 12000<Re<35000. The main goal of the work is to establish a CFD procedure to analyse the flow pattern in the vicinity of the bodies and to predict the position of the boundary layer detachment. The computations are performed with several turbulence models implemented in the ANSYS Fluent code. The direct visualizations and the numerical results are corroborated, with the aim to investigate the positions of the separation points and the flow spectrum developed downstream the bodies.

After decades of development, one of the most mature renewable energy technologies is recognized to be wind energy. Compared to other renewable energy sources the wind potential that can be used to produce electricity is much higher. Currently, the conversion of wind energy into electricity has several advantages, among which can be mentioned the following: "clean" energy source, renewable energy source, low costs per unit of electricity produced. Thus, the progress of future technological innovations must lead to the achievement of wind turbines that are more efficient, more robust, and less expensive than actual technology. The aim of this work is to provide an overview of the Global, European and, especially, Romanian situation of the wind energy market. Moreover, are presented aspects related to innovative constructive solutions for wind turbines used to capture wind energy in areas where wind potential is low.

The presence of water in wooden elements is an important factor in the understanding of the evolution of this material used for a structure. This happens because wood has the ability to change its volume due to climate variations; it can shrink or it can double its size depending on the season. This can influence the mechanical properties of the wooden piece and introduce in the structure deformations and changes in sectional efforts that can be very dangerous. For this study, environmental conditions have been tampered with so that wood that has moisture content of 12% will intake or output water, in order to arrive at a moisture content of 8% respectively 16%. In this way, the moisture content of untreated Spruce (Picea abies) and Chestnut (Castanea Sativa) has been modified in a climatic chamber at certain conditions of temperature and relative humidity. The wooden pieces have been verified for their moisture content in an oven with a temperature of 105°C after a complete dry. The purpose of the study is to follow the behaviour of wooden pieces when found in other environments.

This study performs an exploratory analysis of the evolution of consumption of RES for EU28 countries over the ten years studied. Through the analysis, the document presents: the consumption by sectors of production and by renewable energy sources, analyses the evolution of consumption from RES: between countries and regions. Regarding the consumption of RES, it is increasing, reaching in 2017 compared to 2008 to increase by 147.8%.

This study performs an exploratory analysis of the evolution of primary production of RES for EU28 countries over the ten years studied. Through the analysis, the document presents: the structure of production by sectors of production and by renewable energy sources, analyses the evolution of the mentioned indicators both in total and in detail on each renewable energy source and allows the identification of differences in the level of production from RES: between countries and regions. The analysis shows that these countries have implemented EU strategies in the field and exceeded the proposed target for 2020 starting from 2017. Among the most important RESs in primary energy production were the sources: Hydro, Wind and Solar, in the countries from the EU28 due to the existence of a natural potential that has been exploited and encouraged by the country-specific internal policies, but also due to the development of technologies and lower costs for these renewable energy sources.

Usually, the industrial halls, who are in most cases poorly insulated and have high permeability, are heated with hot air generators or convecto-radiators. Using convecto-radiators is improper and hot air generators, although it is more appropriate, it consumes a very high amount of energy. This paper continues the topic discussed in a previous article [1] in which we presented an alternative heating solution to the existing ones. The heating system mentioned uses an environmentally friendly and cheap fuel (biomass). This paper presents an alternative solution to insulate a burning chamber (BC) with high temperature walls that uses pellets as fuel. This technical solution has the benefit of supplying heating agents to various types of heat consumers and to optimize the construction costs through the materials used. The BC is design with external ribs on here longitudinal direction. For insulating and cooling the BC, a metallic case was design through which atmospheric air is circulated. Three constructive solutions of BCs were analysed. The paper presents the modelling results of the constructive solutions and the calculation method. The calculation was made applying the physical laws that govern this type of heat transfer and was made with discretization segments. Determining the parameters of each segment will allow the user to optimize the equipment design. The main purpose of the study is to conceive an alternative technical solution for insulating the BC, that should be cheaper, easy to implement and able to prepare a second thermal agent for heating.

Ships operating in different shallow-water areas are at risk of grounding due to squat, heel and wave-induced motions. The paper aims not only at assessing the ship squat in any bathymetry, but also to reveal the waves influence on the environment. A 3D numerical model for predicting ship resistance in confined waters by taking the ship sinkage into account is proposed. A time-domain model is used to predict unsteady squat and dynamic acceleration effects for a vessel travelling in non-uniform water depth. A quasi-steady approach where the prediction at each time step is based on steady-state heave force and pitch moment in uniform water depth is used. Resistance, sinkage and trim, the free-surface elevation as well as the wake flow structure are considered in the ship performance analysis. The results show the wave pattern in the subcritical, critical and supercritical regions. The total resistance/drag is calculated at various ship speeds in shallow water using CFD and compared with the calculated deep water resistance. Attention is paid to the verification and validation based on a grid convergence study, as to the exploration of the modelling error in RANS computations to enable more accurate and reliable predictions of the bank effects.

The paper describes a methodology for assessing the hydrodynamic performances of a four blade fixed-pitch propeller working in open water. Both single propeller and twin-propeller arrangements are studied. The numerical solver, which is a part of the Numeca FineTM-Marine package is based on the finite volume method. Closure to turbulence is based on the detached eddy simulation (DES). A double sliding grid technique is used to treat the contra-rotational flow around the propellers. A grid convergence test is carried out to verify the robustness of the numerical treatment. Comparisons with the experimental data for the single propeller are performed twice to validate the ISIS-CFD viscous flow solver for both starboard and portside propellers. Discussions based on the numerical solutions are provided aimed at clarifying the particular issues of the hydrodynamic interference between the two propellers. Finally, a series of remarks are concluding the findings of the present work.

This paper refers to wind tunnel testing of a residential complex located in a crowded urban area in the vicinity of some tall buildings. Due to the agglomeration of certain urban areas, the erection of new tall buildings becomes increasingly challenging, both in terms of location finding and structural load assessment. For a tall building located in such an area, the complexity of the structural challenges is increased by the loads resulting from the wind action. Usually the wind velocity profile from which these loads result is influenced by the roughness height factor associated with the urban areas surrounding the building. In the vicinity of other tall buildings, the interinfluences between the buildings must also be ascertained. Following the request of the project developer, the Technical University of Civil Engineering Bucharest through the Aerodynamics and Wind Engineering Laboratory "Constantin Iamandi" performed wind tunnel static tests of the residential complex using two different roughness heights above the floor of the wind tunnel (corresponding to different terrain categories with respect to wind orientation) and adding models of the existing adjacent tall buildings for some of the wind directions. The paper presents test methodologies used, the wind tunnel set-up, the residential complex static model and obtained results.

The goal of this paper is to review the technologies used for nitrate removal from water intended for human consumption. It also reviews the effects of nitrates on human health and the various legislative provisions in different states. The treatment technologies that will be detailed are: reverse osmosis, ion exchangers, biological denitrification and electrodialysis. For every technology, the following information will be provided: advantages, disadvantages, process performance and cost. Furthermore, there will also be examples of water treatment plants across the Globe that use these types of technologies for nitrate reduction.

The research is focused on realizing a comparative analysis regarding the parameters of an active water-cooling solution for improving the efficiency of monocrystalline silicon photovoltaic (PV) panels. The efficiency of the photovoltaic panels is dependent on the climatic conditions, varying especially with the change of the intensity of the solar radiation and of the operating temperature. The cooling of the photovoltaic panels is a viable solution for both fixed and variable positions of the system. Numerical modelling was carried out on a photovoltaic panel integrated into the façade of a buildings. The water-cooling solution consist in using a water film heat exchanger attached on the backside of the PV panel. The parameters of the heat agent analysed were the temperature, velocity and width of the water film. The optimal water film heat exchanger solution was obtained for a thickness of 3 mm of water film, a velocity of 0.01 m/s and an operating temperature of 20 °C. In this case, the thermal power extracted by the film exchanger reaches values of 140.8 W, with an overall heat exchange coefficient of 48.6 W/m^2.K. During the study, the global heat transfer coefficient and the raise off efficiency is determined for each case.

The study analyses the qualitative influence of different parameters on Dambovita River water temperature along the 17.5km length reach of concrete canal passing through Bucharest City, Romania. Air temperature has been increasing during the investigated last 4 decades with detrimental consequences on the river ecosystem. The simplified physical processes taken into account, equations and numerical methods used to develop a deterministic water temperature model are explained. Different scenarios of possible extreme summer heatwaves with influence on river water temperature are defined analysing the available data. A sensitivity analysis is performed for meteorological parameters such as: air temperature, humidity, short wave solar radiation, cloudiness and wind speed to determine their influence on river temperature.

Renewable energy sources represent efficient and reliable energy solutions for the modern world, as they are eco-friendly alternatives to fossil fuels or nuclear power plants. The technologies available nowadays allow researchers to perform in-depth computational fluid dynamics analysis for systems that can generate green energy. The wind energy industry developed considerably as classic wind turbine models (horizontal axis wind turbines and vertical axis wind turbines) are constantly optimized and new configurations are studied in order to asses better performances. This paper presents the numerical investigation campaign of a reduced scale Lenz wind turbine model. The Lenz model has three blades that are attached directly on a vertical shaft. For the numerical simulations of the model, the ANSYS Fluent software is employed. For the evaluation of its self-starting behaviour the six degree of freedom method was employed and the configuration was studied for different moments of inertia. Furthermore, the chosen range of inlet velocities allowed the investigation of the influence of high Reynolds numbers on the proposed Lenz model and the vorticity magnitude contours were computed for different azimuth angles. Future work includes the validation of the numerical results with experimental data obtained during a wind tunnel testing campaign.

This paper presents the results of an experimental study carried out within the National Institute for Research, Development in Constructions, Urbanism and Sustainable Territorial Development URBAN INCERC, on a system of walls made of ACC blocks, according to the standard SR EN 771-4 [8], having a density of 480 kg/m³ and standardized compressive strength of 3.5 N/mm², using mortar type binder class M2.5 with compressive strength of 2.5 N/mm². It was exposed to the action of standardized fire for a period of 220 minutes, after 10 days from the execution of the masonry. The results showed that, following the tests on the burned samples, extracted from the wall subject to the test, the standardized unit compressive strength decreased by 54%.

Ammonium is an inorganic compound present in water at pH<9. Ammonium has no toxic effects on human health, but its presence in water can indicate a water pollution. The presence of ammonium in groundwater source can be largely determined by the reducing conditions from the aquifer, while in surface water sources it is found only in polluted waters. In water supply systems, the presence of excess ammonium in raw water is not desirable because it can generate problems such as: unpleasant odors, microbial development in the water distribution system, reducing the efficiency of chlorine disinfection and increased chlorine consumption. Over time, several methods have been developed to reduce the concentration of ammonium from water, these being physical, chemical, biological or a combination of these methods. The article presents a review of the technologies currently used to reduce /oxidize ammonium from water. These mainly includes: ion exchange and adsorption, biological filtration, air stripping, breakpoint chlorination and reverse osmosis.

Pneumatic drives are light weight, small-sizes, simple to install and to maintain. Pneumatic drives have a robust design and operation. They are clean and cheap, have no temperature limitation, and so, they are preferred in many branches of manufacturing and process industry. The well-known pneumatic actuators are widely used in closed-loop positioning systems because of their dynamic performance and mechanical flexibility in different electro-mechanical systems arrangements. The goal of the paper is to find the parameters of a closed-loop pneumatic actuator so that a good dynamic behaviour of the system is obtained. The parametric tuning process is developed by using numerical simulation technique. So, it was seen that using a proportional controller, the pneumatic actuator has an asymptotic stability for different values of the proportional gain K_p. Starting with K_p = 8 the system remains stable, but oscillations of low amplitude appears.

Renewable energy sources represent one of the solutions to mitigate the impact energy production, transportation and use have on climate change. Solar heat for industrial processes is an emerging solution that has yet to reach its true potential. When an industrial consumer is considering installing an energy source on site, a technical and financial analysis is performed to find the optimal solution. However, the analysis is characterized by a certain degree of uncertainty due to the assumptions made, that influence the final decision. Hence, the profitability of renewable energy-based solutions can either be overvalued or undervalued when compared to a fossil fuel-based solution. In this paper, the solar heat potential for the industry in Romania is calculated. Then, a past to present analysis is performed in order to assess the real benefits an industrial energy consumer would have gained had he considered a few years back to cover a fraction of its heat consumption with a solar heat source, by using the real historic data regarding the energy market evolution. The results show that subsidies are necessary in order to make solar heating profitable and more appealing for industrial applications in the market conditions from Romania.

In this article, the authors reviewed the modern technologies for manufacturing transparent, bifacial, flexible panels and other similar solutions. Passive or active cooling solutions, with air or water vapor, or energy storage solutions are analysed. If the passive air cooling of the photovoltaic panel can achieve a reduction of its temperature by only 10 °C, by active cooling, a cooling with over 30 °C can be obtained. These technologies are aimed to improve the energy efficiency of photovoltaic panels. The article presents examples of photovoltaic panels' own applications, as well as hybrid PV, realizing the cooling of the PV panel and the recovery of the thermal energy in the form of hot air or hot water, with good efficiency.

A small Savonius wind turbine of helical type was tested in an open jet wind facility for identifying the optimum position of the rotor blades aiming the maximization of static torque. The two blades of the wind turbine of U shape were twisted up to 180⁰ from bottom to top and three values for blade overlap were considered i.e. 0.35, 0.2 and 0.0. The turbine torque was measured for no load conditions and wind velocities between 2-8 m/s. In the same time the air flow through Savonius rotor was observed by using a visualization setup aiming to identify the correlation between the torque and the flow pattern inside the returning blade at rotating angles where the torque has highest values. Best results for the torque coefficient of 0.72 and power coefficient of 0.265 were obtained at a wind velocity of 5.8 m/s and low overlap ratio of 0.2. By measuring the overall torque of the rotor for each case study, the positive effect of pressure recovery was explained as a result of air flow through the blade overlap from the concave side of the advancing blade to concave side of the returning blade for a certain interval of the rotating angle a = 50-60°.

Archimedean screws have been used for centuries, but only for pumping water. In the last decades, a growing interest appeared to also use them as hydro turbines for electricity generation. While Archimedean screws are already well optimized for working as pumps, studies are still carried out to identify those parameters that assure the best performances when they operate as turbines. This paper proposes a simple yet efficient procedure for the design of an Archimedean screw operating as a turbine. The most important formulas proposed in the paper are those for calculating the outer diameter and the rotational speed of the screw. The condition imposed for finding the diameter is the maximization of the torque produced. The calculation of the diameter requires to estimate the volume of the water buckets that form between the blades of the screw. It is practically impossible to find an analytical formula for this volume, but a rough estimate can be found easily. This rough estimate is corrected afterwards based on regression of data available for turbines that already operate with good efficiencies. The rotational speed is then determined based on the condition that the rated discharge can run through the turbine operating at the rated speed.

The paper presents the state of the art for thermal energy accumulators using the latent heat phase change usable in cars with either internal combustion engine or electric. The new materials with high storage capacity are presented and the most important achievements in this field of thermal energy storage on vehicles. The case study presented in the paper brings some information necessary for the development of thermal accumulators, with phase change materials, showing the important parameters and characteristics and what values they must have (e.g.: required and accumulated energy; charging and discharging time; latent heat, geometric characteristics). The paper presents a possible classification of these types of batteries, thus facilitating the development of products specific to the applications in which they are included. The work will continue with numerical and experimental studies on models developed based on the case study described here. If at present, in the case of electric cars, a reduction of approx. 20% of electricity was obtained by implementing thermal batteries with phase change material, then studies or research become necessary to accelerate their development on an industrial scale in competitive economic conditions.

Wedge or tapered foundations of buildings, which have greater top cross-sections than bottom ones, are not often considered as a design option due to their shape. However, precast wedge foundations could be considered as "quick foundation systems" in case of light structures which should be rapidly installed. Similar to tapered piles, this foundation shape can offer besides the bottom base resistance, a good lateral contact between the inclined concrete faces and the surrounding soil. The paper presents the experimental results of two wedge foundation specimens subjected to axial compression tests conducted in accordance to actual standards. The results recorded on sites are presented under the form of pressure-settlement diagrams and are compared with similar values recorded for usual prismatic foundations. The study is completed by an environmental impact analysis made on the two systems along with potential benefits and loads, beyond the system boundary, at the foundations' end-of-life.

Building sector focuses on surpassing challenges linked to energy efficiency and mitigation measures related to greenhouse gas emissions, in consequence, it needs to improve building performance in the interest of decreasing impact over environment. Buildings with reduced long-term operating cost, environmental-friendly and moderate construction costs can be achieved only by multi-object optimization and cross-disciplinary analysis, embodying a holistic approach. Following the main principles of the holistic sustainable design approach, the paper presents a sustainable experimental modular laboratory involving various strategy in regard with sustainable building, as resource, cost and material efficiency, health and well-being, environmentally conscious design, life cycle design, modular design, reusable/recyclable element, environment-friendly demolition method, safety design, consideration of life cycle cost, materials cost and waste disposal cost. Besides the installation of renewable energy sources and conservation of energy, the holistic construction of laboratory included also an integrated design with consideration for technology, operation and maintenance, which involved the implementation of a monitored energy management system. The system provides an accurate overview of the building's performance during operational phase. Although the monitoring is still in an incipient phase, recordings showed promising results regarding the behaviour of recycled-PET thermal wadding used for insulation and indoor comfort conditions.

The current study was realized in three schools located in regional Romania. The results of this article draw upon the diversity of school's typologies analyzed: new, existing refurbished and old. The analysis was carried using answers given by 138 children to a survey that covered questions related to their learning environment and health problems. Children were asked to rank the perceived quality of several indoor environment parameters (IAQ, outdoor air quality, illumination, noise), the stressful and friendly nature of the schools, and their overall satisfaction. The survey was accompanied by experimental measurements of air temperature, humidity, noise and illuminance levels, CO2 concentration and dust particles. The most prevalent symptoms experienced at school were sneezes (34.1%), fatigue (18.9%), runny nose (14.5%), stuffed/blocked nose (11.6%), and headache (8.7%). Out of the five main health symptoms reported at school, the majority has been recorded in the renovated school.

The indoor air quality is one of the main factors influencing the comfort in a building. This subject has already been covered by several studies in the case of adult's work environment. The research study is focused on the air quality in a primary school classroom and the children's sensation related to interior comfort. In this article we will present the results of the air quality experimentations when using a ventilation system. The classroom is equipped with a heat recovery unit. In order to perform CO2, temperature and relative humidity (RH) measurements, we used ten portable measurement units. The sensors have been set in different spots of the classroom. The heat recovery ventilation unit had an important influence on the air quality when it was running. The observed result of this phenomenon was that the measures were homogeneously distributed in the classroom instead of being concentrated in different points. Moreover, it was found that with 17 m3/h/pers. the indoor CO2 concentration can be dropped below 1000 ppm. The last part of the experimental study was based on a survey with different question regarding air quality, temperature and noise.

The paper focuses on the numerical modelling of a rural Water Distribution System (WDS), supplied from a deep well, from which the water is pumped in a water tower (storage tank). Consumers are fed gravitationally from the water tower, with variable demand over 24 hours. Simulations were carried out in EPANET 2.2 using two methods: Demand Driven Analysis (DDA) with outflow issuing from emitters, and Pressure Driven Analysis (PDA). To minimize numerical instabilities, a particular attention was paid to the groundwater well (modelled both with variable, and constant hydrodynamic level), as well as to the connection of the water tower to WDS (where the connection was made either using 2 pipes, or a single pipe). By applying the DDA and PDA methods to the resulting 2×2 configurations of the hydraulic system, a total of 8 sets of simulations (solutions) were obtained and compared. The most advantageous pair of method and configuration is recommended to be considered when modelling a complex (e.g. urban size) WDS with groundwater supply and storage tanks.

The present study focuses on the operation of a drip irrigation system for greenhouses rose cultivation in Adunatii-Copaceni, Giurgiu County, Romania. The numerical modelling of the irrigation system was performed in EPANET 2.2, using the pressure driven demand model. The pumping schedule fits the real operation, where five greenhouses are irrigated successively each morning, directly through pumping from a groundwater source. Fertigation is applied for each greenhouse every 5 days, in the evening, through pumping from a storage tank. Despite the hydraulic assumptions adopted to model the groundwater well and dripper lines, the computed results match the values of the outflow rates measured for the dripper lines of the real drip irrigation system. Simulations are useful to investigate, at no cost, different scenarios attached to the operation of the studied drip irrigation system.

Estimated energy production for a wind farm depends on the wind shear who is influenced by both the roughness factor and terrain specifics. Tall towers measurements allow accurate determination of the velocity profile around the mast. Away from the point of measurements the reliability of the extrapolated data depends on complexity of the terrain and the extrapolation technique applied, as the error may exceeded 30 %. In terms of this, the use of one high mast to predict the energy potential is inaccurate. However, installing more than two tall masts is expensive. Therefore, a novel approach is used to analyse the wind potential for semi-complex terrains - one tall and one short (reference) masts. The novelty in the study here is that the short mast collects wind data for high and low terrain points. The data collected shows that the complex character of the terrain significantly increases the thickness of the surface boundary layer making the data obtained with 20 m masts quite unreliable. However, the 20 m mast data provides useful information for boundary layer that is used for refinement of the tall tower wind shear. Thus, the use of high and short masts improves the estimated energy production.

Solar systems are widely used to mitigate the environmental impact of the energy sector and their importance has constantly increased due to the recent EU's strategy to lower the CO₂ emissions. Moreover, the newest Energy of Buildings Directive empathises the importance of producing energy from renewable sources to decrease the overall impact of buildings over the total end-use energy consumption. Generally, the systems' performances are highly correlated with the incident solar radiation and outdoor air temperature. Thus, being able to accurately forecast these two parameters represents a vital step in dimensioning and maximizing the overall energy production. This Paper presents the results obtained by implementing a deep recurrent artificial neural network (ANN) trained with on year solar radiation data harvested from the UPB campus. The time series data was modelled using a special ANN architecture – the LSTM (Long Short-Term Memory) – due to its special designed internal 'memory' which increases its capabilities of predicting temporal sequence data. The model uses sequences of 24 hours and the resulted mean squared error (mse) for both training and validation data is under 30%.

The advancement of wind energy technology brings about an increase in the size and height of the wind turbine towers. As the upscaling of the conventional steel tubular tower is problematic, alternatives are being investigated. In this paper, several configurations were reviewed and the lattice tower was identified as a possible solution. This study analyses and compares the structural performance of the two tower configurations, tubular steel and lattice, of equivalent height, stiffness and mounted rotor, in two sets of tower heights, 120 m and 150 m. The towers are mounted by the baseline 5 MW turbine developed by National Renewable Energy Laboratory (NREL). The results indicate that lattice towers are a suitable alternative to the tubular towers, providing significant material savings for a similar structural behaviour. Comparable bending moments were recorded in the base of the structures. The most demanding operating condition of the wind turbines was identified to be system braking cause by a sudden increase in wind velocity outside of the operating range. The 150 m lattice tower responds with excessive displacement during this abnormal operating condition; this is a potential issue that can cause generator failure if not accounted for in the rotor design.

Infrared thermography is a very effective non-destructive control method for detecting and locating defects. It is a technique that allows to obtain, with the help of an equipment called thermal imaging camera, the image or thermal imprint of a targeted area in the field of infrared radiation. Infrared thermography deals with the acquisition and analysis of thermal information obtained using non-contact infrared scanning equipment.

In the global context of environmental protection and the reduction of its pollution, wastewater treatment has a special role. Starting from this general framework and considering the need for an integrated approach to water as a natural resource, the aim is to introduce new treatment technologies in which human intervention tends to zero. That is why modelling, and simulation techniques highlight automation solutions and their implementation. In our paper we tried to model a biological purification process using Simulink techniques.

The aim of this paper is to develop an advanced system of indoor parameters monitoring and management to increase operational efficiency and improve the life in buildings. The system will monitor the environmental parameters, using a system of sensors for temperature, relative humidity, and the main indoor pollutants measurement. Reports related to the building's CAD plans are defined. Thus, for each room, the corresponding indoor parameters can be viewed in real time. In addition, using the read parameters a heat index is computed by several methods. The solution helps to locate the problems with certainty, due to the relationship with the CAD plans. It could support the facilities managers by alerting maintenance teams when the parameters exceed certain values. The sensor system is cheap, and its scalability allows the management of an unlimited number of objectives.

The extinguish process using the water mist jet is one of the most efficient system for hydrocarbon flame accidentally developed. The environmentally friendly of the system is an important challenge. Both free jets characteristics are analysed in aim to have a quick suppression of the flame. The paper is focused on the geometrical shape of the cone realised by every jet (flame and water mist). On this basis the relative position of the jets is decisive in aim to obtain the desired effect. Experimental measurements were made, and the results are presented in the paper including the infrared temperature field. The experimental analysis allows to find the adequate angle between jets for the flame extinction. So, the optimum position of the water mist jet applied on the fire was found. A thermal flame extinguish efficiency evaluation is presented, too. The system is non pollutant and the damages are reduced.

The presented paper reveals a numerical study of the risk of condensation over exterior wall of a typical residential room. The study is based on CFD methods with implemented conjugate heat transfer. The analysis is contributed by a study of the impact of the heat released from conventional room radiator with various heat loads. This way, the resulting surface and dew point temperature distributions are derived over the simulated exterior wall. The results demonstrate that with the increase of the room relative humidity, the percentage of the external wall area, which might be affected by condensation increases significantly. This effect is observed regardless of the selected increase of the radiator heat load (in this particular study, the range is between 1000 W and 1500 W). For the range of relative humidity values from 40% to 60%, the area with increased risk of condensation increases to above 80%. This result demonstrates the crucial importance of the control of the room relative humidity within occupied premises, especially if condensation mitigation measures must be applied. The presented analyses and assessment method are rather innovative for the presented engineering area and would be in help in the buildings and indoor environment design process.

The paper is a study on different types of masonry partitioning walls in a high rise reinforced concrete walls building. It will be built in Bucharest, Romania. The masonry walls are made of clay bricks for the first 4 cases studied and aerated concrete blocks for the last 2 cases. They are designed to bare the in plane and perpendicular efforts they are subjected to in the elastic stage. The effect these masonry walls have on the structures is shown. They have an important influence over the buildings natural vibration periods and the slabs reinforcement design and shear stresses. The plastic hinges development is shown for all 6 cases. The pushover diagrams are compared separately for directions X and Y.

The water loss is a phenomenon which attends the water supply system on its operating lifetime and it represents the difference between the water volume measured at the input of a water distribution network and the water volume billed to the end-users. The water loss reduction is an important topic for the water supplying companies and the knowledge of the real water volumes lost from a supply system is an essential element in water balance. The water losses may be classified in "real losses" and "apparent losses": the apparent losses cannot be quantified, but the real losses can be estimated by calculus. The complexity of this phenomenon lies in the fact that this water losses can't be calculated with a single equation, generally valid for each real situation. The equations mentioned in the technical literature can be applied to a specific situation. This paper presents an experimental study of the variation of the hydraulic parameters in a PVC water flow pipe in two cases: 1. normal operation and 2. leak simulation, when a circular hole is drilled into a PVC pipe. Furthermore, the results of this study are discussed and analysed in order to calculate the value of the leakage exponent N₁.

Healthcare infrastructures are critical and have elements which are likely to fail or to get collapsed in disaster scenarios (earthquakes, pandemics, etc.). There are many parameters and factors to evaluate their preparedness, but resilience has outstood in recent investigations. Hospitals must not only be prepared for disasters to come, but also to reach the nominal operation in the aftermath as soon as possible, as these infrastructures play a critical role in modern societies. The aim of the study is to evaluate and assess different insights into resilience, as well as marking possible improvements, providing a deeper understanding about the topic and concepts that surround the definition of resilience. The result is the constitution of a new assessment tool based on semi-quantitative and quantitative models. The model can be scaled and applied to internal systems in healthcare infrastructure such as HVAC facilities.

Currently the optimization of raw materials, energetic efficiency and the reduction of environmental impact are aspects of such importance at the time of choosing a product, process or system. The healthcare buildings are a kind of building composed by a whole group of systems, products and processes. This means a great margin for improvement in energy efficiency and environmental impact caused during the construction as well. The main goal of this project is to verify the viability of applying a case of study of Life Cycle Analysis (LCA) in a healthcare building. After the analysis of the results obtained in previous studies, a series of advantages and drawbacks have appeared as a result of applying this tool in healthcare buildings. The result has been beyond satisfactory, since clear conclusions have been obtained from an exhaustive analysis. Among the most important conclusions, it should be noted that the LCA technique is a great asset to evaluate environmental impacts. The application of LCA methodology helps to reduce the total environmental impact generated during the construction of a healthcare building, having a great impact on social benefit as well as an economic benefit. This last is usually associated to the reduction of waste and operative costs and in the energy savings. Also, it has been proposed some solutions to the main drawbacks. These can be the draw of a guide for the application of the LCA technique or the implementation of educational courses.

The aim of this paper is to predict the energy consumption of a wastewater treatment plant from Romania, taking into account the flowrate, concentration of BOD, TSS, COD and the energy consumption. For the mathematical model the logistic regression was applied. The input data used were from a waste treatment plant in Romania, for a period of 2 years 2015 and 2017, a total of random 403 dataset. The treatment technologies of WWTP consist of advanced biological treatment SBR (nitrification, denitrification, and phosphorus removal), aerobic sludge stabilization, dewatering, storage and chemical disinfection. Octave software was used to build the model. The answer of the model refers to the fact that for a given situation there will be high energy consumption or low energy consumption in the wastewater treatment plant (WWTP). Performance of the model was compared with real value.

Servomotors are special direct current or alternating current electric machines which have an adjustable rotational speed in a wide range, in both directions and which aim at moving a mechanical system along a trajectory in a prescribed time. Servomotors are used in various applications: robotics, machine tools with numerical control, aerospace technology, medical installations and others. Stepper motors are special synchronous machines that have a different construction than the classic one and are used in precision drive systems, with open loop such as: aircraft on-board equipment, timing and recording systems, electronics, office equipment, robotics industrial, etc. This paper experiences the speed control of a direct current servomotor, type SM-S2309S, with the help of the Arduino UNO platform, which is the simplest solution for the development of electronic applications. The study experiences also speed and step control of a stepper motor, type 28BYJ-48, with the Arduino UNO platform.

This paper is concerned with the experimental investigation of jets formation in a classic microchannel with low aspect ratio a/r=0.125. The confined jets are obtained in a Y-shaped microchannel using isopropyl alcohol and ethanol in a viscous outer medium represented by mineral oil. In the cases with high flow rate of the inner jets the interface has an important contribution on the velocity distribution inside the jet.

A holistic approach with high level of replicability and financial feasibility for the public existing fund of buildings is undertaken, in order to transform existent public buildings, that are serving communities, into nearly Zero Energy Buildings. Finding large scale solutions from both technical and financial point of view, to reduce energy consumptions and CO₂ emissions for the existent building fund represents at this point a major challenge for all stakeholders. Several existent educational units (kindergartens, schools, high schools) from a city in Romania were analysed, in order to improve their energy efficiency and to transform the typical existent educational unit into nZEB. A framework package of technical solutions is proposed and the effect of its implementation is analysed, in terms of energy consumptions and CO₂ emissions reductions. Economic analysis is undertaken, to identify the feasibility of the nZEB concept implementation. An alternative approach is analysed for public authorities, in order to transform groups of existent buildings, which are serving communities, into nZEB.

Complex energy systems need to evaluate their performance through the achievement of its own objectives but also by comparison with best practices. This can be realized by identifying the key performance indicators (KPI) that clearly monitor the progress towards project goals. The work focuses mainly on the identification and categorisation of KPIs through a quantitative approach for the case of implementation of a hybrid energy supply system into the existing district heating network of University Politehnica of Bucharest. The main results of the study show that two levels of KPI can be defined: technology specific and overall DHC system. If on the technology level, the approach is to use the specifics standards already existing for the main technologies, for the system level, little information is available and consequentially, a method for calculating separately the cooling and heating impact in terms of energy, environment, and economy is proposed.

Transpired solar collectors have been widely studied during the last 30 years by experimental, mathematical, and numerical approaches. However, numerical approaches have been frequently simplified because of insufficient computing power. Transpired solar collectors are complex to analyze via numerical simulation mainly due to a difference in scale between the very small holes on the absorber plate and the entire collector size. Thereby, the aim of this paper is to analyze the independency of high-resolution meshes for a longitudinal slice of an entire transpired solar collector and to determine a proper geometrical discretization leading to a good accuracy of the numerical results in a reasonable computing time. This study has shown the importance of the mesh size and refinement in order to capture the thermal and flow characteristics inside unglazed transpired solar air collectors. The obtained results highlight the fact that even with the lowest size of mesh the outlet temperature and temperature variation inside the solar collector is despite everything close to the finest mesh. Thus, for global analysis of a simple solar collector a coarse mesh could be sufficient. However, an increase in the mesh size it has an influence on the temperature and velocity profiles behind the perforated absorber plate.

The characterization of the flow from mixing tanks equipped with different impeller models is used for optimizing mixing of working fluids. In this paper is presented a study on flow characteristic of two types of impeller immersed in a tank at different depths and with different rotational speed. Using PIV technique flow distributions for several mixing configurations are obtained. The experiment can be used to determine the still zones in the mixing tank and for the optimization of the mixing parameters.

The renewable energy policy strongly encourages the use of all renewable sources of energy. ICPE-CA starts to develop a new hydrokinetic turbine to be implemented in small rivers or water channels with a low investment cost. In a first step, the characterization of a laboratory reduced scale turbine model is performed. The hydrokinetic turbine model is implemented in a free surface water channel. The produced power for many flow rates and rotation speed of the turbine, as well as the detailed flow characterization (PIV measurements) are presented.

The paper presents a study of hydraulic modelling of the drinking water and sewage distribution network in Nasaud City, Bistrija Nasaud County from Romania, which includes a calibrated simulation of the flow through networks, and allows the elaboration of a future strategy of developing the networks of water and sewage. The need to develop hydraulic models as accurately as possible results from the fact that, by creating and calibrating the hydraulic model of a system, a variety of system problems can be identified, solutions can be mitigated to them by addressing the problem of rehabilitation, expansion or design of new systems. The results can be tracked both at the scale of time, and in real time by simulating the functioning of the system at these time scales. We decided to approach the problems of sizing and verifying the network using software solutions packages, in this case the MIKE URBAN calculation program, which can import and export network data as ESRI ArcView shape files, allowing the network data to be directly imported and exported into and from ArcView. Thus, the network is completely resolved, the calculation of hydraulic sizing and verification of the network being performed in all nodes.

A possible strategy for reducing energy consumption and carbon dioxide emissions in order to protect the environment is the recovery of heat from wastewater. This study aims to achieve an improvement in the effectiveness of heat transfer by changing the flow parameters by using a double heat exchanger to recover the heat from greywater. The results, the thermal energy from wastewater can be recovered, the effectiveness ranged between (25 % — 45 %) with the discharge of (0.15-0.51m3/h) lower to higher, respectively. The cold water flow has a clear effect on the heat transfer efficiency, the decrease in cold water velocity led to the increase in heat transfer performance. This technique is simple to implement and inexpensive. It can be designed and built on the basement of the multi-storey building. The dual heat exchanger splits the flow into two-pipe, decreasing the flow rate velocity and thus, increasing the heat transfer efficiency.

During the summer, vehicle passengers may reach a comfort state, if the sun direct solar radiation do not affect them. Human body parts exposed to the sun, experience a high uncomfortable state which have a direct impact to the global sensation of the all body. The purpose of this study is to deepen the knowledge about the thermal phenomena that occur in cabin and its effects to the thermal state experienced by the driver during a summer sunny. This way we compare temperatures, humidity and Equivalent Temperature (t_eq) index acquired with an advanced thermal manikin for 3 scenarios. Results reveals that for a direct solar radiation of 500 Wm⁻² temperature inside of the car rise with 10°C. Also, the values of t_eq for the manikin parts exposed exceed value of 36°C leading to a very hot thermal state for all body.

The Fibre Reinforced Cementitious Matrix (FRCM) composite material is a relatively new retrofitting system which overcomes the limitations related with the use of organic adhesives. FRCM system is used to increase the strength and overall ductility of masonry and concrete structures. This paper presents the results of an experimental program on plain concrete columns strengthened by FRCM under uniaxial compression loading. Six columns of square 30x30 cm cross-section and 100 cm height made of low-strength concrete were cast in place. Two columns without confinement are used as reference, while two columns with one layer of FRCM and two columns with two layers of FRCM are used to investigate the influence of FRCM confinement level. The FRCM system consists of high-strength carbon fibre mesh and cementitious mortar. The performance of FRCM strengthened columns is evaluated in terms of ultimate axial load carrying capacity, ultimate axial deformation, ultimate stress and ultimate strain. The experimental results are also compared with the numerical results obtained according to ACI 549.4R-13 code.

The use of numerical simulations in Fire Safety Engineering provides faster and more affordable ways of research and development, with the drawback that their use is often conditioned by available expertise and thorough validation. In this paper, the results of two small scale numerical simulations of artificially generated smoke are being validated by comparison of the smoke's light extinction coefficient values and those of the visibility levels in the testing enclosures with the results obtained through experimental testing. The influence of grid size on simulation accuracy and computational time is evaluated by presenting the small gain in accuracy and the important increase in computational time for different sized meshes, showing that at least in numerical simulations dealing with artificial smoke, a larger grid size can produce fairly accurate results. A comparative evaluation of the effect that the positioning of the measuring devices inside the testing enclosure has on the results is also performed, both for the experimental setup and the numerical simulations.

The paper describes the main features and advantages of European standard EN 1993-1-5 in the design of plated structures. Compared to other types of steel structures, plated structures are more prone to local buckling and therefore required design rules to cover such a phenomenon. The concept of the article focuses on The Reduced Stress Method. A steel box girder chooses for numerical example was fabricated of S235 steel, has 7 panels with transverse and longitudinal stiffeners and was tested in 1985 at the Testing Laboratory of the Research Institute for Transportation Engineering, in Bucharest.

The costs of damages in both social and economic aspects are increased as a result of several significant earthquakes worldwide, the economic and social losses are a function of damage of the buildings because the buildings are vulnerable to earthquake damage [1]. In this study a probabilistic methodology FEMA P-58 is applied for seismic performance assessment for Iraqi educational reinforced concrete building in order to calculate the performance in terms of two aspects, the first one is the direct economic losses which include repair costs and repair time and the second one is social losses which include casualties and injuries. This methodology is prepared by ATC, the American Applied Technology Council and its prepared for Federal Emergency Management Agency (FEMA) in 2012. The study is a continuation of other research papers related to applying the same method to the same building that the researcher undertook for the purpose of evaluating the performance of the building when exposed to earthquake and calculating the losses resulting from these damages by choosing different aspects of each research in terms of the method of simplified analysis or the calculation of damages and losses.

Within last years, construction projects have quickly accelerated in both number and size. This study deals with some of effects of performance management and its outputs from service and cost viewing. By focusing on the relationship between the two main stages in construction projects, that is the design and implementing stages, the research is going on using method of questionnaire survey including four main factors: the state of design process, the state of implementing process, the state of interaction between the two stages (design and implementation) and the state of problems resulted during and after construction. A questionnaire was distributed into 50 construction projects and the data are collected and analysed through SPSS. The results have shown that there is a weak relationship between design and construction stages in local construction projects. Research showed also that it could not be claimed that this situation (weakness of the interaction of stages) is responsible of defects in the performance of these projects, which in turn results in service and cost problems. Interpreting for this situation was that the results reflected the weakness in the actual management performance in the local construction projects.

The study presented in this paper was conducted on a site pertaining to the distribution & storage component of the oil industry, the business of which was mainly the supply, using railroad and road transportation means, followed by storage in tanks and trading of petroleum products (e.g. gasoline, diesel oil, various oils). To carry out its activity, the site had the following technological equipment: vehicle loading platform/railway unloading platform, storage tanks, pumping station, hydrocarbon separator, technological transport pipes, storage areas, administrative buildings, etc. Based on the characteristics of industrial sites, a synthesis of the particularities of these site types was made. To that effect, the direct connections in terms of the specificity of the main and auxiliary activity were taken into account, as well as the handled chemicals and raw materials, but also how the waste was managed during the operational processes.

The condensation process represents the phase change phenomenon through which the water vapours from air are transformed into liquid together with heat release. The phenomenon can take place either in the bulk of the fluid and it's named homogeneous condensation, or it can appear on a solid surface and it is heterogeneous condensation. This paper proposes to provide an insight into the condensation phenomenon through the lens of experimental and numerical approach in different configurations. The focus is set on the condensation/evaporation process inside vehicles' cabin as the evolution towards electric vehicles is starting to make a mark on the industry. The paper presents the impact of the HVAC system on both, energy consumptions and driving security. As the electric vehicles are prone to a general driving range of around 200 km depending on the battery systems, this driving range can be significantly reduced up to 40% by the usage of the HVAC system [1]. Therefore, the methods for reducing and maintaining the condensation phenomenon away from the glazing surfaces of the vehicles' cabin, especially on the windshield are going to be tackled in order to provide a general view of the actual state of this subject.

Sustainable development requires the use of sustainable energy systems. Energy use will increase worldwide, and geothermal energy consumption for both electricity generation and heating will also increase significantly. Sustainable use of geothermal energy means that it is produced and used outdoors, which is compatible with the well-being of future generations and the environment. This paper provides a review of the links between the development of geothermal energy used in HVAC systems and sustainable development, as well as a review of the sustainability assessment frameworks currently available.

Maps are known since antiquity, the oldest examples are from the 6th to 5th centuries BC. From the Babylonian world map, known as the Imago Mundi, maps evolved continuously. In the present day, maps allow us to visualize data in new and informative ways and to present it in an interactive manner. In recent years, web mapping technology has become a necessity for urban planning, and not only, by helping the population to take better and informed decisions. When communicating with decision-makers or only to take the best decision we need first to assess the answers to all the following questions "What and Why and When and How and Where and Who" and what better way to do this than by using Open Data? The governmental and administrative institutions have data in the form of historical maps, topographic maps, digital terrain models, statistical analysis, and other types of data. Our goal was to make these data available for the public in an easy and interactive way, by creating web maps, applications, and a website that gathers all these data.

The purpose of this application is to see whether or not it is cost-effective to insulate the base of ordinary houses, made of load-bearing masonry. Certainly, the isolation of the base is suitable for structures of high importance, as well as historical monuments, but the common man does not live in a structure of high importance. Is the solution cost-effective for the average person? To test this hypothesis, we proposed a low structure (GF + 1) of confined masonry, located in a seismic area (Bucharest, ag = 0.30g, Tc = 1.6 sec) urban. The example is a multifamily duplex home.

The proposed structure being low, its own vibration period is small enough to be located in the area of maximum dynamic amplification in the response spectrum. For the simplified analysis we analysed starting from the hypothesis of a seismic force represented by the equivalent lateral force, according to the provisions of P100-1/2013. The basic concept of base isolation, respectively the decoupling of the structure from the foundation ground, also implies the increase of the own period sufficiently so that the structure is no longer in the area of maximum dynamic amplification of the response spectrum.

Drawdowns and filling may cause instability in slopes without adequate levels of protection against failure. In this paper, a numerical approach utilizing the finite element method (FEM) was employed to examine the seepage and slope stability of a typical earth-fill dam. Finite element software (GEOSTUDIO 2012) was used to carry out both steady-state and transient seepage analyses on Chamrga earth Dam in Iraq to study the seepage and upstream slope stability during normal water level, filling stage and drawdown conditions for two scenarios. To include water levels during the filling and drawdown variable linear water heads with time were identified as boundary states in the transient seepage analysis. The quantity and direction of water flux, existing gradient, and safety factor were calculated for all scenarios. The results revealed that the stability of the slope during drawdown is highly impacted by how fast its pore water pressure dissipates.

The paper deals with a comparative analysis between original and advanced masonry. Both are of high practical interest in buildings and monuments. Particularly, in seismic areas, where they are submitted to the strong actions of earthquakes, the Latin principle Primum non-nocere should be applied. That principle was considered by the Venice Chart in 1964. Later it was resumed by ICOMOS-Iscarsah Recommendations in 2001. The paper presents first some historical data for each type of masonry. The original masonry has a long history when it was well checked by time. On the contrary, the history of advanced masonry is very short. Among the basic proprieties of the original masonry is the ductility of the lime mortar. Its mechanical strengths are lower than that of bricks. In these conditions, the original masonry exhibits the phenomenon of self-defending by adaptation. It is not the case of the advanced masonry which remains stiff. By physical modeling, the main proprieties of original and advanced masonry were proved. Then, by numerical modeling, the testing results were generalized and prepared for further use in design and research. From the comparative analysis results that each of the two types of masonry has specific fields of application.

The paper deals with enhancing the strength of original masonry with polymer grids by preserving its basic physical properties of strength, stiffness, and potential energy. The behavior of the original masonry is carefully analyzed. The adopted solution for seismic protection of masonry was based on Landau's Theory of dislocation. The basic idea of the patented method of reinforcing original masonry was related to the vertical joints of the original masonry. The suitable reinforcement for the original masonry should have high strength and long durability. The paper is suggesting some applications of reinforcing the original masonry. The tests on physical models confirm the practical value of the proposed method of reinforcing the original masonry. The numerical models extend the field of application regarding the polymer grids as suitable reinforcements.

This paper shows an aggregated compact cooling liquids (refrigeration system) used in air conditioning technological process who works in present with R407C refrigerant. The paper has focused on theoretical study case. Regarding F-Gas Regulation the optimum alternative for this application is R134a refrigerant with Total Equivalent Warming Impact (TEWI) calculation.

The overall aim of this search investigated the effect of DO, alkalinity, and pH on nitrification in biological aerated filter system BAFs. The laboratory experiments by three identical pilot-scales downflow of BAFs using three different sunken materials types, 0.78±0.60 mm activated carbon-based material bed, 0.95±0.58 mm sand-based material bed, and 3.28±2.14 mm ceramic particle-based material bed, as attached growth zone in the treatment of municipal wastewater. As results of the experiments showed that activated carbon-based material bed when the mean concentration of dissolved oxygen was 6.76±2.25 mg/L and the mean alkalinity concentration was 77.25±2.60 mg CaCO₃/L and the mean pH value was 7.21±0.20 the mean nitrification efficiency has reached of 90.11%. In the sand-based material bed when the mean concentration of dissolved oxygen was 7.33±1.82 mg/L and the mean alkalinity concentration was 77.56±2.77 mg CaCO₃/L and the mean pH value was 7.22±0.20 the mean nitrification efficiency has reached of 87.74%. In the ceramic particle-based material bed when the mean concentration of dissolved oxygen was 6.37±1.84 mg/L and the mean alkalinity concentration was 77.31±2.71 mg CaCO₃/L and the mean pH value was 7.22±0.20 the mean nitrification efficiency has reached of 85.17%.

Considering the current EU regulations, the GWP limit for comercial refrigeration systems is 150 starting with 1^st of January 2022. This study uses a selection software for condensing units to evaluate the options available on the UE market which can fulfill the GWP limit. For this purpose a theoretical comparison between R404A (past), R449A (present) and R744 (future) condensing units with a cooling power of 10kW is made. The COP in the range of ambient temperature from 0°C to +40°C is the main criterion evaluation. Size and weight are also evaluated as secondary criteria. The results of COP evaluation are similar with conclusions from other studies and confirm that R449A unit has better COP than R744 and R404A. Also the size of the unit in case of R744 is three times bigger than R449A unit. The main conclusion is that even if R744 has low GWP and fulfill the legislation requirment it has not good efficiency. Further studies should be made in order to find a good solution for small cooling capacities.

The blind walls, arranged between the neighboring buildings, are at the same time structural walls for the buildings from the typological groups analyzed in this paper. The foundations we can find in these are in 95% of cases continuous, surface foundations: stone or brick masonry; simple, unreinforced concrete (due to the knowledge from the respective historical moment) or reinforced concrete.

Depending on the type of floor and the materials used, there may be: flexible floors, which do not have a horizontal diaphragm behavior (rigid and resistant washer), specific to floors with unidirectional discharge or rigid and resistant floors, which have a horizontal diaphragm behavior (rigid and resistant washer), specific to monolithic floors in RC.;

Regardless of the type of floors that are discharged at the turbocharged walls, it is observed that, at most, there are discharges only on one side of the turbines, and not on both sides as on the structural walls inside the buildings.

These aspects must be taken into account even if, through the safety measures and methods, the turban walls end up passing from type 1 to type 2, with the unloading of the floors.

Currently, concrete is the most widely used structural material in road infrastructure. Concrete is a sensitive material, cracks and micro-cracks may occur during operation. Although the cracking/micro-cracking of concrete does not implicitly cause structural damage, it creates a path for corrosive factors, which leads to decreased structural durability caused by material changes and reinforcement corrosion. The self-repairing ability of concrete refers to the process of closing cracks to prevent the entry of potentially aggressive agents. Concrete used in bridge construction is usually covered with a waterproof layer and a layer of asphalt mixture, which also acts as a wear layer, but which can prevent the entry of water containing corrosive ions, the natural aggressiveness of the environment or accelerated corrosion by the penetration of thawing substances etc. Road infrastructure repair works affected by degradation processes are costly, time consuming and lead to a reduction in traffic flow, by partially closing it during interventions. To overcome these shortcomings, over time, several types of concrete with self-repairing properties have been developed, based on several methods such as: pipe networks, superabsorbent polymer capsules and textile fibers, bacteria etc.

The present paper is intended to illustrate the main advantages and disadvantages of four different ten storeyed concentrically braced frames designed under severe seismic actions. All structural members (braces, beams and columns) had built up I-shaped cross-sections, sized according to the provisions of P100-1/2013 and SR EN 1993-1-1. Each of the four considered braced frames were subjected to nonlinear dynamic analyses, using three base excitations (from the 1977-, 1986- and 1990-Vrancea earthquakes), recorded at the INCERC Institute in Bucharest, calibrated all to a peak ground acceleration value of about 0.3 times the acceleration of gravity. Rayleigh damping was taken into consideration. The maximum values of inelastic deformations, bending moments and axial forces in various structural elements, the amount of energy dissipated through plastic deformations and the estimated steel consumption were compared. The extreme values of base shear forces and horizontal displacements were observed. The successive formation of plastic hinges in the different braced frames was analysed.

As we are going through advancements in construction field and the imperatives of reliability requirements of the structure, soil always have an important role as a material that supports the whole structures, the Soil structure interaction is one of the most vital arts, nowadays and with the new technologies of soil testing and as we get closer for a better understanding of soil behaviour, we have the chance to model and anticipate the real behaviour of the structures resting on the soil. In this study, the effect of soil as a supporting material will be revealed and carefully studied to clarify and dye out the importance of Soil structure Interaction, and its effect on the governing efforts that are used in design of the structural elements. Soil structure interaction it is not just about the coupling of the soil and the structure, but also studying the effect of construction phase change between the adjacent buildings. The elastic settlements are going to be calculated using analytical solution, Boussinesq iterative solution, and elastic solution of Abaqus finite element model, then will be coupled as springs that model soil elastic half space (EHS) to check the impact of SSI.

This paper proposes an experimental and numerical study (based on CFD – Computational Fluid Dynamics technique) dealing with a glazed transpired solar collector (GTC), having the distance between the glass and absorber plate of 50 mm. The behaviour of the GTC has been studied for different air flow rates. Based on the results obtained, it can be concluded that this GTC configuration behaves best for air flow rates of about 300 m³/h. On the other hand, further studies are needed to improve the numerical model (especially regarding the introduction of boundary conditions based on measured data).

The present paper is intended to point out the main differences existing among the seismic design procedures for concentrically braced frames contained in different seismic design codes. Two ten storeyed concentrically braced frames were designed taking into consideration the provisions of three seismic design codes: the Romanian norm P100-1/2013 [1], the European standard EN 1998-1:2004 [2] (respectively SR EN 1998-1:2005 [3]) and the American code AISC 341-16 [4]. All structural members of the concentrically braced frames (braces, beams and columns) had built up I-shaped cross-sections, sized according to the provisions of SR EN 1993-1-1:2006 [5]. Each designed frame was subjected to static nonlinear analyses. The seismic design loading state in different kind of structural members and the estimated steel consumption, the maximum values of base shear forces and horizontal floor displacements were compared. The successive formation of plastic hinges and the plastic failure mechanism in the different designed frames was analysed. A configuration with additional potentially plastic zones along the frame girders was proposed in order to improve the behaviour of the concentrically braced frames during static and dynamic nonlinear analyses.

The National Geological Museum is a representative building for the typology of historic unreinforced masonry structures built in Romania at the beginning of the XX century. The seismic behaviour was studied with respect to the displacement capacity, by comparing the initial structural configuration of the building with the retrofitted one. Taking into account the irregularities of the structure and the localized reinforced concrete jacketing works done in the 80s', global results were proven to be misleading. Thus, relative floor displacements were used to study the behaviour of individual walls involved in local failures. Limit state thresholds based on relative displacements were used in order to calibrate the initial model with the post-earthquake damage assessment and then they were compared to the results obtained for the retrofitted model to establish the effectiveness of the strengthening works.

The paper presents results from a study on monitoring the long-term variation of the dynamic characteristics of an 11-story reinforced concrete building located near Bucharest. Since the deployment, in December 2013, of a permanent monitoring system, 89 seismic events with a moment-magnitude (M_W) larger than 3.8 were reported. Out of these, 80 were recorded properly by the seismic sensors and the data was used to extract the fundamental frequency and the damping ratio of the building for each event. The main method used to compute the dynamic parameters was the Random Decrement Technique. A dependency of the resulting fundamental frequencies on the maximum accelerations at the base and on top of the building was observed. Due to the structural peculiarities, the fundamental frequency of the building on the transverse direction was lower than the one on the longitudinal direction, this being reflected also by the experimental results. The maximum drop in the fundamental frequency was reported for the M_W=5.5 October 28^th, 2018 seismic event. By performing this type of analyses, the dynamic parameters of buildings can be tracked over long periods of time and their variation under seismic excitation can be assessed, allowing rapid detection of structural health alterations.

The Nonlinear finite element (FE) model can accurately predict the behaviour of reinforced concrete (RC) with the RC beam's safety with and without CFRP that is designed for resistance against high temperatures. Transient thermal finite element analysis is performed using the ANSYS software. The beam was subjected to a short-duration, high-intensity (SDHI) fire at the bottom and side surfaces, in the form of transient temperatures versus time, whereas maintaining constant transversal loading on the highest body. The validation of the finite element model without CFRP is confirmed by comparing the results with experimental testing results that are carried out at similar model conditions within the same geometry, reinforced, and boundary conditions. After that, added the carbon fiber reinforced polymer sheet (CFRP) at the bottom and side surfaces of the RC beam during fire exposure as a parametric study to investigate the effect of CFRP on the strength and stiffness of the RC beam at high temperatures. The results showed that CFRP strengthening would have a significant impact on RC beam stiffness.

Worldwide common efforts towards developing a sustainable, competitive, eco-friendly and efficient built environment have led to a new legal and technical spectrum of rules and requirements for high energy performance buildings. Provision of solutions for a continuous thermal envelope is sometimes essential in designing such buildings. Mitigating, as much as possible, the thermal bridging phenomenon is highly important and should be accounted from the very beginning in the design process. This issue can be addressed through various solutions when it comes to thermally insulating the superstructure but can be quite challenging and limited at infrastructure level, particularly for buildings set in areas exposed to earthquakes. This paper explores existing technical literature, local codes, norms and standards, with the twofold purpose of: (1) providing a view on the relevant available research and design prescriptions; and (2) outlining incipient general design considerations related to the feasibility of applying specific thermal insulation materials beneath buildings located within the main seismic regions of Romania.

Paper presents the results obtained in situ and in laboratory for a test section where the soil has been improved by mixing with a lime-based hydraulic binder. The treatment has been applied in order to obtain a more uniform soil bearing capacity, thus reducing the differential settlement that could appear between adjacent foundations or under the same foundation. The test section has been performed by mixing the local cohesive soil (silty clay) with 4% special lime-based hydraulic binder, then compacted in 3 layers, 20 cm thick each after compaction, resulting a final compacted layer of 60 cm. For this treatment a laboratory study has been conducted in order to determine the optimum binder admixture. The physical and mechanical characteristics of the improved soil have been studied in laboratory and in situ for 3 curing times: 3, 7 and 28 days. In laboratory have been carried out tests for identification and classification, for determining the density and water content, followed by mechanical tests as oedometers and shear box tests, while in situ Lukas plate tests have been performed. Paper presents results of all tests, including analyses and interpretation.

This article presents an experimental study of the chemical and mechanical properties of the cement paste / aggregate interphase. Interfacial Transition Zone (ITZ) represent the contact zone of the cement paste with the aggregate with a thickness of about 20 - 50 μm. This zone has different mechanical and chemical properties compared to the bulk paste. Cement paste / limestone aggregate composite samples were performed to allow the study of the chemical and mechanical properties of ITZ. The cement paste is made with Portland cement with a water/cement mass ratio of 0.4. Calcium concentration profiles in the ITZ show a high concentration of calcium due to the presence of portlandite and ettringite. The nano-indentation tests indicate weakness of ITZ compared to bulk cement paste.

Since the subway systems are constantly developing at a high rate to cope with the increasing number of commuters, their safety is a great challenge and extensive research was done to fulfil the safety regulations in this field. Numerical modelling represents a modern research method used more frequently in the academic environment over the last decades, being constantly validated through comparisons with results of other classical research methods. This paper presents a thorough analysis of the numerical studies on smoke evacuation in emergency situations from tunnels and subway stations, with a focus on the research concerning the use of platform screen doors (PSD) in emergency situations generated by fires. The numerical simulation software mostly used are Fire Dynamics Simulation and Ansys Fluent (based on Computational Fluid Dynamics modelling technique), their results being extensively compared with experiments and analytical formulae. Since most of the studies focus on determining the specific values of some fire related parameters (critical velocity of the ventilated air, backlayering distance of the smoke, maximum temperature in the smoke layer or maximum concentration of smoke pollutants), a lack of research regarding the efficient use of PSDs concomitant with the ventilation system in emergency mode has been identified.

Asphalt mixtures are being used in road construction more and more, to the deficit of concrete surfaces. Due to the additives as well as the new technologies being used to obtain asphalt mixtures, the results are vastly improved which can lead to a better behavior in day to day situations, even under heavy traffic. This study means to show the way in which changing the binder influences the properties of the mixture. So, the chosen binder course, type BAD 22.4, will use different types of binder (bitumen), more specifically: a 50/70pen bitumen; a 50/70pen bitumen modified with flexible semi-rigid polymers and a PmB 45/80-65 bitumen, modified with polymers by crosslinking. The asphalt mixtures will be characterized by their volumetric properties, Marshall Characteristics and their behavior to dynamic tests. The results presented in the form of charts and tables were obtained in the Road Laboratory of the Technical University of Civil Engineering of Bucharest. The conclusion that can be drawn is that depending on the type of binder used, the results obtained differ with a noted improvement of the resistance to permanent deformation and creep, in the mix which uses the binder modified with polymers by crosslinking technology.

For seedlings production, healing and acclimatization are the most important processes in obtaining healthy and vigorous plants. Influence of photosynthetic photon flux density (PPFD) on a healing tunnel environmental parameters was investigated. The experiments were carried out at HORTING institute's micro-production greenhouse using 9 alveolar trays with 104 eggplant seedlings each, placed in two sections of the specialized tunnels for healing and acclimatization of seedlings. In each section and in the research greenhouse was measured the levels of photosynthetic photon flux density, of temperature, of the relative humidity and the level of CO₂ concentration. From the meteorological station of the HORTING institute, data on the variation of outdoor temperature, relative humidity and light intensity were downloaded. The variation of the micro-climate factors in the two sections according to their external environmental conditions were compared. One of the conclusions is that seedlings that have benefited from an additional artificial source of light have a more intense photosynthetic activity. The difference on CO₂ concentration in the two sections over the same time period lead to this conclusion. This gives the certainty of obtaining healthy and vigorous plants in the sections with supplementary lighting.

When talking about the urban challenges we face today at a global level, population growth and urbanization ranks high in the charts. Both challenges can be found in the Middle East and especially in Dubai, one of the fastest growing cities in the world - a rapidly developing urban settlement supporting an ever-increasing human population. With a very warm climate, the United Arab Emirates are struggling to develop strategies and solutions to decrease energy consumption. Among the major consumers in Middle East are the building therefore an integrated approach using renewable sources is mandatory. Within the Solar Decathlon competition the Romanian team of students proposed a house prototype to answer Middle East challenges. In this paper we present the developed model, its structure, systems and we demonstrate its potential as a positive energy balance building using numerical simulations.

The issues related to the propagation of outside noise to the occupied spaces are more frequent, especially in urban areas where different types of noises are present (constructions, traffic, etc.). It is medically proven that noise has negative effects on health: anxiety, lower intellectual performances, stress, fatigue or higher blood pressure. With the national refurbishment program of old buildings the constructors are insulating and replace old wood frame windows with more energy efficient ones. Despite the clear benefits in terms of energy reduction there are still some questions about the sound insulation of the facades. If the windows replacement is done in a wrong way the situation can be aggravated as air and noise can overpass. In this paper using experimental measurements it is evaluated the impact of thermal refurbishment of an apartment on the acoustic comfort. The data showed that the windows represent the weak part of the facade and incorrect mounting severely affected the indoor sound pressure level.

Experimental research in fire safety engineering is often characterized by a low repeatability mainly caused by the destructive nature of the fire phenomena. One of the ways that these shortcomings might be avoided is by using numerical simulation for research in this particular branch of engineering. Accuracy in numerical simulation comes through validation of the results by comparison with experimental testing, and in this regard, this paper presents the use of the PyroSim fire simulation program, which is a user interface for the Fire Dynamics Simulator software package, for the purpose of simulating non-toxic smoke in a way that accurately describes its behavior and properties observed in experimental testing. A full-scale experiment has been conducted for the purpose of determining the optical properties of non-toxic smoke produced by a smoke machine and this paper presents the way that this smoke can be accurately represented in the simulation program, for the purpose of providing a basis for future simulations of experiments using smoke machine generated smoke. The methodology employed can be used in further research involving simulated smoke, such as CFD representations of firefighter training, people evacuation from smoke-filled enclosures and smoke exhaust in buildings.

Highly viscous fluids (HVF) are used in food sector as raw materials (melted vegetable, animal fats) or finished products (chocolate, sorbets), in construction sector as liquid state of Phase Change Materials (PCM) used to store thermal energy inside building structure or building materials such as liquid concrete, bitumen and tar, in automotive industry as PCMs used to passively cool batteries, and many others. Some applications are rather new and lot of research has been done, in the last decade, to find mathematical models for predicting HVF behaviour, in heat and mass transfer processes in scraped surface heat exchangers, in vegetable fat melters and in waxy crude oil transport pipelines. Better results could be obtained by enhancing HVF thermal properties such as increasing the thermal conductivity of PCMs by adding metallic powders, or by finding new natural materials (vegetable fats) which can replace more expensive and harmful ones (waxes) for PCMs. This study was performed to shortly present the main applications in which HFVs are being used, the main advances and findings made in the last years and the current challenges and research possibilities which are likely to be explored in the future.

This paper presents the influence of the thermal bridges effect on heating demand in residential buildings using numerical simulation. Quantitative evaluation on temperature field is performed by means of linear heat transfer coefficient. Specific details of existing thermal bridges within the building envelope have been identified and selected for analysis. The model simulation was performed using COMSOL Multiphysics software. Thermo-physical properties of the building envelope elements were selected from the software database and the boundary conditions have been setup. Meshing was done by dividing the virtual domain into an optimum number of finite elements. Model validation was done by comparative analysis between the values of the linear thermal transmittance obtained through numerical simulation and the reference values stipulated in C107-3-2005 technical regulation (catalogue of building thermal bridges). Specific solutions for correcting the thermal coupling between different building envelope elements were adopted in order to reduce the linear thermal transmittance up to 23% and the heat flow rate up to 71%. The evaluation of space heating demand shows the impact of correct treatment of thermal bridges on the reduction of energy consumption.

Despite the latest global developments (new materials and less polluting technologies) and in spite of the treaties signed at world level (the Kyoto Protocol 1997 and the Doha-2012 amendment, the Paris Treaty 2015) regarding global climate change, the implementation of these measures to reduce pollution, protect the environment and strictly respect them, leave it to be desired. Climate change caused by global pollution, in large industrial regions and in major cities of the world, has led to and continues to lead to a decline in the air quality we breathe in Europe and in the world. The degree of urban and industrial agglomeration of the cities, contributes significantly to the increase of local pollution by mixing all the pollutants present in the air, this mixture of pollutants is favoured by street canyons and implicitly by the significantly lower dispersion of pollutants in atmosphere. Monitoring air quality in the urban environment and measuring as accurately as possible the concentrations of air pollutants, through the presence of as many sensors and monitoring stations in the monitored area as possible, as well as the implementation of analysis and interpretation hardware and software solutions of the data gathered in real time by these monitoring stations, is very important for the future of large urban agglomerations.

Even since Antiquity, in ancient Greece 4th century BC, or in China, the 3rd century BC, but not only there, people have imagined and even created automatic mechanisms, mechanisms that somehow were trying to be shy replicas of real examples of intelligent life from nature, including replicas of Man's creation, such as the first bronze man, but nonetheless, non-intelligent replicas. Subsequently, in the modern age, attempts have been made to simulate a human neural network, as well as the first steps towards artificially simulating the functioning of the human brain. We will present in this article concepts of neural networks and some practical applications in the field of artificial intelligence and their capabilities to simulate autonomous thinking through advanced programming and complex assimilation of large data sets, using the three major learning paradigms, namely: supervised learning, unsupervised learning, and reinforcement learning. All these new concepts, over the past 75 years, and the advances in information technology have led to the emergence and development of practical applications of artificial intelligence. In this way, the human dream of creation tends to live and fulfil itself, why not, even in the coming years.

Transport is a significant branch of the economy due to its contribution to the creation of gross domestic product. In order to ensure a reliable transport network that boosts trade and economic growth, prior to the construction of new national roads and motorways, it is necessary to ensure a proper technical condition of the road. Therefore, road network administrators have to attain a balance between the program of maintenance / repair / rehabilitation activities and the works that can be executed within the limits of the available funds so that the investment achieves the highest profitability and the road network either viable. There are currently a number of factors that influence the decision-making process in prioritizing maintenance work as well as allocating funds so that the investment achieves the highest return. Therefore, a multi-criteria decision-making approach is needed to ensure a balance between the program of maintenance / repair / rehabilitation activities and the works that can be executed within the limits of available funds. In the present paper, the authors proposes to develop a decision support model based on the principles of the GIS information systems, to help the road network administrators to take decisions that prioritize the maintenance works.

Currently, worldwide, different technologies or different materials are used to increase the performance of the asphalt mix. Depending on climate and traffic conditions, each country has adopted specific solutions that improve the behaviour of asphalt pavement over time. Because each of these products has a particular effect, it is not possible to add a product to the mix to improve all of its technical features. The performance of asphalt pavement depends on the optimal selection of basic materials: natural aggregates, filler, bitumen, polymer and fiber. The aim of this paper is to investigate the relationship between the constituents of the asphalt mixture and its physico-mechanical properties. Characteristic properties of bitumen used in the mixtures were determined by conventional bitumen tests and rheological tests according to SHRP. After optimum bitumen content was determined, the influence of the polymer in the mixture was studied. SMA mixes were prepared with different penetration grades bitumen, from different sources and performance tests were conducted in order to evaluate the behaviour of the mixtures.

The post-earthquake evaluation of structural integrity is a critical point to be addressed in case of emergency situations triggered by the occurrence of seismic events. A valuable method that can provide important indices to experts performing this operation is the monitoring of structures with seismic sensors that record how the structure responds to earthquake ground motion. In the case of permanent monitoring systems, reliable information can be obtained by comparing the data recorded before, during and after the earthquake, and checking if any abnormal vibrations of the structure or dynamic parameter changes have occurred. The presented study analysed comparatively, for an 11-story reinforced concrete building, vibration data recorded before, during and after the October 28^th, 2018 earthquake (M_W = 5.5). Continuously recorded data was used to determine the hourly values of the fundamental frequency of the building. The short-term behaviour (72 hours) was assessed, highlighting the modal parameters variation during, before and after the earthquake. In addition, an analysis of the data recorded one and a half hours before the earthquake and one and a half hours after the earthquake provided useful information on the evolution of the building state and on how this "recovered" after the earthquake.

The removal of nitrogen compounds in wastewater is receiving wide attention and the effluent standards will be tougher in the near future. The overall aim of this article is a review of biological aerated filter systems BAFs for removal of the nitrogen in wastewater. The BAFs technology is based on the principle of biofiltration where can be operated either in an upflow or downflow mode depending upon the position of the influent feed, where the media which attached growth zone can be either denser than water to give sunken media or less dense than water to produce floating media. The BAFs combines biological treatment and ammonia-nitrogen and solids removal in one reactor unit, where accumulated solids are removed from the BAFs through backwashing.

This paper presents an innovative calculation method that simplifies the present calculation in the existing Romanian solar methodology, but also brings a new approach to the problem of determining the actual efficiency of a heating system using solar panels during the actual hours of sunshine. This new method will also make better economical estimations by including a new calculation method that is adapted strictly to solar panels applications. Both proposed methods, include a new approach of determining the thermal and economic indicators faster or more precise. The results shown in this article, validate the new calculation method and offer new perspectives on real-time hourly solar system performance evaluation. Those results show that although the actual hourly efficiency of the solar panels increases over a small period of time, daily system efficiency that includes the consumer's heating needs, decreases due to the limitation of the required thermal energy over a longer period of time that exceeds those sunshine hours. This paper provides a new vision regarding the way solar systems are treated and suggests some adjustments that need to be made in calculating the solar systems. Thus, due to a considerably higher heat input over a given period of the day, it is concluded that these systems work much better in the case of extra storage of this energy (larger storage tank) or by adjusting the indoor temperatures (through automation) during this solar charging regime.

Climate change has become a fundamental concern for scientific researchers, architects and engineers, so it's required to improve the performance of sectors responsible for city and building infrastructure. Burning fossil fuels to produce electricity and heat is the biggest cause of climate change and emissions, and represents one third of total greenhouse gas emissions. Thus, buildings become responsible for improving the external environment, either by construction phase, rehabilitation process or by maintainability process. This work reviews and evaluates elements of influence for solar ventilated building facades in order to improve this field of research as this solution allows to achieve important energy savings.

Under the current conditions of road traffic growth, importance should be given to the use of construction products whose technical characteristics have to be tested and to comply with the regulations in force. In our country at present there is the European standard EN 13043:2003 regarding the conditions that natural and artificial aggregates must meet in order to be used in asphalt mixtures. As is well known, these conditions are presented in the form of categories of values to be set by the designer to result in an asphalt mix with certain characteristics. However, this standard does not contain a national annex with specifications on the aggregate categories depending on the type of asphalt mix correlated with the technical class / road / street technical category. The majority of beneficiaries that use aggregates in the production of asphalt mixtures have problems on the national market because there is no correlation between this standard and the national provisions in force, namely the AND 605/2016 (version in force on this date). This paper analyzes the conditions that the natural aggregates for the bituminous mixtures must have and correlates the performance of the aggregates with the performance of the asphalt mix.

The building seismic performance assessment can be defined as a posterior phase of investigation in which a detailed analysis is executed in order to evaluation of seismic damages and quantify the sequences of the earthquake for a building, this approach could be probabilistic evaluation or deterministic one. The aim of this paper is to perform seismic damage evaluation for educational multi-storey reinforced Concrete Building in Al-Mustaqbal University College (MUC) in Al-Hilla City, Babylon governorate in the middle of Iraq by using FEMA P-58 methodology. A 3D mathematical modelling, pushover analysis by using SeismoStruct software. In addition, incremental dynamic analysis (IDA) and fragility curve according to FEMA P-58 are developed in order to obtain damage limits in term of performance levels of the case study building. Fragility curves are useful tools for showing the probability of structural damage due to earthquakes as a function of ground motion indices. IDA is performed for those simulated building using twelve ground motions with scaling peak ground acceleration increased every 0.1g until it achieved 1.5g to determine the drift capacity of the building in four performance levels, operational (OP), immediate occupancy (IO), life safety (LS) and near collapse (NC) as defined in FEMA P-58. Based on those capacities, fragility curves were developed in terms of peak ground acceleration (PGA) and elastic spectral displacement for drift levels with lognormal distribution assumption.

The subway transport method is come more popular in the last years and in some cities has become the primary public transportation mode. Many people are using the underground transport system because it is an efficient and fast. However, one environmental disadvantage of any underground transport system is that it operates in a confined space that may permit dust accumulation. The passenger typically spend only 30–40 min in metros, the air pollutants emitted from various interior components of metro system as well as air pollutants carried by ventilation supply air are significant sources of harmful air pollutants that could lead to unhealthy human exposure. This article presented the actual situation of the air quality from the subway transport system from Bucharest. An investigation was conducted among for underground subway stations to the examination of practical operation conditions of their cooling units. The overall field testing included information such as air conditioning system formation, equipment types and system.

In this article the effects of different airflow rates introduced by the ventilation system are investigating by numerical simulation over the thermal comfort of the driver in a regular vehicle. The 3D LDV (Laser Doppler Velocimetry) measurement for the diffusers velocity field was imposed as boundary condition at the inlets of the investigated domain. Also, the flow rate discharged by each diffuser was measured for the first three positions of the air conditioning system. In the numerical model which was previously validated we imposed the boundary conditions from the experimental sessions. Thermal comfort was assessed by calculation of the equivalent temperature on the surface of a virtual manikin on the driver place and by the determination of the maps of Predicted Mean Vote (PMV) and the Draft rate indices. A first conclusion is that the results of the three flowrates may assure the comfort of the front passengers and a draft sensations and uncomfortable state for the rear passengers.

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