Table of contents

4^TH INTERNATIONAL CONFERENCE ON RHEOLOGY AND MODELING OF MATERIALS

October 7-10, 2019/Miskolc-Lillafüred, Hungary

The conference ic-rmm4 was organized together with ec-siliconfl the 1^ST EUROPEAN CONFERENCE ON SILICON AND SILICA BASED MATERIALS by the

International Scientific Advisory Board (ISAB),

International Organizing Committee (IOC) and

Session Chairs

ic-rmm4 image, Abstract and Acknowledgement are also available in this pdf.

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

Manufacturing of ceramic goods most often involves compaction of granulated powder. There are numerous phenomena that complicate rheological equations of densification during the compaction process and therefore render these equations practically useless without computer assist. We present a simple generalized model of densification of granulated ceramic powder based on Ballhausen-Gąsiorek's, Messing's and Pascal's models. Experiments have proven a linear variation of density along the direction of compression and changes of dynamic and kinematical coefficients of friction. The variation of the dynamic coefficient of friction is in the range from 0.15 to 0.25.

In this research, the compacting process and rheological properties of kaolin and bio-original additive (sawdust) mixtures were investigated based on compaction pressures and times. Relative compaction curves as a function of forming pressure and time were determined, the authors enabled to precisely specify the changes of the rheological models and rheological characteristics of these powder mixtures which have variable particle compactions and size distributions. varying the compression pressure and changing the composition ratio of the kaolin and sawdust powder mixtures leads to considerable changes in the rheological properties of the prepared mixture.

The dynamics of local temperature in the area of injection of drug solutions with regard to their physical and chemical properties is studied. It is shown that infrared thermography allows to visualize the processes of intra tissue rheology of drugs both when the temperature of injected drugs differs from the local temperature of tissues in the injection area and when their temperatures are equal. Methods of infrared diagnostics of tissue homogeneity, as well as methods for identifying, specifying the localization, shape and size of tumors, foreign bodies and local inflammations have been developed. It is shown that artificial temperature contrast of veins filled with blood and/or drug solutions in relation to the tissues surrounding them allows to visualize these structures using a thermal imager in real time. It is established that the dynamics of the local temperature of tissues at the injection sites of drug solutions depends not only on the temperature of the injected drugs, but also on the presence and severity of their local irritant effect. It is shown that the local irritating effect of drugs is manifested in the places of their injections by local hyperthermia, hyperemia, swelling and soreness. A direct dependence of the severity of the local irritant effect of drugs on the value of the total concentration of ingredients and the degree of hyperosmotic activity of solutions was established. Therefore, dilution of drugs with water is a way to reduce their local irritant effect.

Fine glass waste has been found to be a suitable addition to lime mortars because of the high amorphous content. The behavior of fresh air lime mortars and natural hydraulic lime mortars modified by foam glass dust is assessed with the purpose of exploring a new application of this waste dust as lime mortar admixture. The rheological parameters were correlated with relative density measurements, water retention abilities of mortars and air content in mortars. The effect of foam glass dust was found to be dosage-dependent. The fresh mortars behave generally as Hershel–Bulkley fluids with an evolution of the rheological parameters with admixture content. The replacement of lime by foam glass dust caused a reduction in mixing water reducing the yield stress simultaneously; however, the viscosity of the resulting mortars slightly increased. A change in behavior of mortars from shear-thickening to shear-thinning was observed. The natural hydraulic lime based mortars showed a gradual change from thixotropic to rheopectic behavior with increasing glass dust addition. The foam glass dust appears to be well suited to air lime plaster mixtures used in machine thin-layer rendering due to its plasticizing properties, and ability to increase water retention and reduce air content in the mortars.

In this paper, a welding simulation procedure is developed using the FE software MSC Marc to predict the residual stresses.Numerical simulation was used to predict the thermal, mechanical and residual stresses behaviour in dissimilar material welded pipes which were found to be in good concurrence with experiments. Both two-dimensional FE model (2D) and three-dimensional FE model (3D) models are used to simulate the residual stressesin different directions in several regions of the weld zone under the same welding conditions. The 2D modelwas used toreduce the time and cost of numerical simulation.The aimof the present work is to understand the evolution of residual stresses (axial, radial and hoop stresses) in weldments. The results of thesimulationreveal that the hoop and the axial residual stresses around the weld region arenoticeablyvarying from those in the steady range.

This work reports the influence of porous ZrO₂-MgO ceramic composition on its structure and mechanical properties. The bimodal pore structure were formed by introduction of organic pore forming particles into the initial powder composition and due to the voids between ceramic powder particles. It was shown, that the mechanical parameters of the porous ZrO₂-MgO composite are substantially defined by the value of the microstresses, the MgO content, and, apparently, the formation of a percolation structure. Thus, it was shown that by varying the composition and the size of the pore-forming particles, it is possible to achieve a high degree of identity with the structure and properties of natural bone tissue.

The "Time-Temperature Superposition" known from rheology has long been a useful tool for studying the behaviour of asphalt mixture. Dynamic modulus values are measured at different temperatures and frequencies can be thoroughly studied using the master curves defined by using this principle. The master curves are usually constructed using the sigmoid functions. However, other types of functions could be used for this purpose as well. One such option is the Ramberg-Osgood material model designed to model the cyclic behaviour of soils. The present article seeks to find out how accurately the use of the Ramberg-Osgood material model can describe the material behaviour of asphalt mixtures, and if there are any new highlights compared to the commonly used master curve determination techniques.

The molar mass of polymers is a basic property that defines the appropriate processing method and the field of application of polymers. Therefore, the measurement of molar weights is a crucial point of polymer synthesis. In absence of modern but expensive equipment a rheology-based method can be used to define the molar mass with reliable result. By evaluation of molar mass, the entire polymerization can be monitored and controlled.

During my experiments polylactic acid alternatives (PLLA, PDLA, PDLLA) have been synthesized by direct polycondensation methods. According to the relevant literature, by this method and with the adequate setup of its parameters 10⁴-10⁵ g·mol⁻¹ molar mass can be reached. The two most important parameters are the process time and temperature that strongly effects on the value of molar mass of polymer. In this work standard polycondensation method has been used to produce the mentioned polylactic acid alternatives then the molar masses of polylactic acid polymers were calculated by followed the correlation of Mark – Houwink relation.

In this present work, zeolite-alumina powder mixtures were prepared via mechanical activation technique using planetary ball milling. A comprehensive investigation of microstructure for the raw materials and the produced mixtures was done using different characterization techniques like XRD and SEM, furthermore the rheological behaviours of the mixtures has been accurately examined based on compaction pressure and time, as a result, the complex rheological properties and models of the prepared powder mixtures were described and estimated. The rheological behaviours show a substantial change with increasing the applied pressure.

The characteristic features of the rheological behavior of dielectric suspensions based on titanium dioxide modified by aluminum and phosphorus and the inter relation between the nature of modifiers and the modifiers-initiated polarization processes at the interface is shown. It has been established that ERFs based on titanium dioxide simultaneously modified by donor and acceptor impurities function stably in the temperature interval 20-80°C, which predetermines the possibility of using them in electrically controlled devices that heat up during operation. The participation of both modifying components in polarization processes proceeding on the titanium dioxide surface is confirmed by its dielectric spectrum. Thus, on the dependence of dielectric loss factor on frequency two maxima have been identified that correspond to the number of different-type inclusions in a sample.

The results of studies concerning freshly prepared clay-cement sealing suspensions based on Bełchatów and Patoka polymineral clays, Portland cement and the addition of sodium water glass as the initiator of the hydration process were reported. Flow curves were determined in a coaxial cylinder system. On their basis, power of destruction and rebuilding of the thixotropic structure was calculated. Changes of the elasticity modulus G' and viscosity modulus G'' were determined by oscillatory measurements in the plate - plate system at variable frequencies. The influence of the type of clay mineral and its content on the tendency to form a thixotropic structure was defined.

The aim of this paper is to study rheological properties of uncured magnetorheological elastomers comprising iron particles dispersed in silicon elastomer in relation to particle rearrangement by external magnetic field into oriented structures as this process is strongly affected by viscosity. Studied systems vary in used filler volume concentration (0 to 30 vol. %). From measured flow curves flow consistency index is extracted first by fitting experimental data to Herschel-Bulkley model followed by applying two concentration dependency models (Maron-Pierce and Krieger-Dougherty) to normed consistency. Results and model predictions are discussed.

One of the complex optimization problems arising in technical applications is the cutting path problem for CNC sheet metal cutting machines. This problem is to optimize the tool path for the CNC technological equipment when cutting a fixed set of parts allocated on sheet metal. The time of cutting process is one of objective functions for the optimization problem. This objective function depends on six parameters of cutting process: 1) cutting speed; 2) lengths of the cutting tool path; 3) speed of idling motion of tool; 4) length of idling motion; 5) number of piercings; 6) time of one piercing. When programming NC program, speed of cutting is defined by the user of the CAM (Computer-Aided-Manufacturing) system and considered as a constant. However, this is actually not the case. Consequently, the problem of exact calculation of objective function is arisen. In order to solve this problem, the correction coefficients for the cutting speed value defined by the user must been calculated. Obviously, these coefficients will vary for different thicknesses and grades of metal. The paper presents the results of investigates, which made it possible to find the functional dependences of the cutting speed for the CNC laser cutting machine (CO2) on the number of NC program commands for the following metal grades: 1.0114 (thickness Δ = 1-10 mm) and AWAIMg3 (Δ = 1-5 mm).The statistical materials of experiments were processed by using software "Mathcad". The received results show that the actual average value of cutting speed is monotonically decreasing function depended on number of NC program commands. In addition, the calculation of the actual cutting speed provides not only an accurate calculation of the value of the objective function, but also, as a result, the correct finding of the optimal tool path

Poly (vinyl alcohol) (PVA) membranes have found wide application in biomedicine and pharmacy for their unique properties such as biocompatibility, elasticity and the ability to absorb large amounts of water. Also carbon nanomaterials have shown great potential in a number of applications in regenerative medicine. Nanodiamonds (ND) are a unique class of carbon nanoparticles that have become known thanks to their biocompatibility, highly functional surface and unique physical, chemical and optical properties. Nanocomposite membranes based on PVA and ND were prepared by a solution casting method to achieve an even distribution of ND in the PVA matrix. The resulting nanocomposites have excellent properties derived from ND and PVA. The mechanical properties of the membranes improved significantly with an increase in ND, suggesting a strong chemical interaction between ND and PVA. The SEM showed a uniform distribution of ND in the PVA membrane. From the results of the work we assume that ND are a suitable nano-filler for PVA membranes. This work examines the properties of ND-reinforced PVA membranes and their potential use in biomedical applications.

Tires that are simply thrown away are a serious environmental problem and safe disposal is a difficult problem. Using the crumb rubber (CR) obtained from shredding of those scrap tires in roads is an alternative solution to their safe disposal. On the other side, excessive rutting in the bituminous layer is a structural defect associated with functional implications. Wheel loads and high pavement temperatures are environmental factors which the main cause of premature rutting. Modified binders and rut resistant mixes especially gradations can reduce premature rutting. The object of the paper to solve two main problems: firstly, the solution to the problem of the tires waste to safe disposal and; secondly, to study the rutting behaviour in bituminous mixes modified by tires waste in CR form. In this paper, two types of bituminous mixes, stone matrix asphalt and bituminous concrete those are used to carry wheel tracking test. The results are shown by using Marshall Test that 6% of CR content by weight if normal binder 60/70 content and optimum binder content for the binder in bituminous mixes is 5.1% & 5.5% by weight of mix is have improved the bituminous mixes. In addition, results indicated that the mixes prepared with a modified binder by CR are good in forming rut resisting mixes. The benefit of this study is the tires waste disposal in an environment-friendly way and better road to withstand rutting.

The localized plasticity development was studied for a wide range of pure metals and alloys in single-crystal and polycrystalline state as well as nonmetallic materials, alkaline halide crystals, ceramics and rocks. Using photographic and digital versions of speckle photography, the localization of plastic flow in the test samples was investigated on specially designed units having high spatial and temporal resolution. According to the analysis given here, the different stages of plastic flow are related both qualitatively and quantitatively.

This work deals with investigating the effects of solid-state phase transformation on residual stresses during the welding of low carbon and high carbon steels. In this study, depending on MSC Marc code, the simulation considers the local microstructure properties changes due to the thermal welding cycles. A sequentially coupled thermal and mechanical 2-D finite element model (FEM) was used. In FEM, phase transformation temperature diagrams are used to anticipate the amount of martensite in the fusion zone (FZ), and heat affects zone (HAZ). The simulation results demonstrated that the residual stress in low carbon steel is not affected by the volume change caused bythe austenite-martensite transformation. In contrarily,the residual stressesin the high carbon steel are considerably influenced by the martensitic transformation.

The effect of PVC additives (30, 50, 70 wt.%) on the electrical resistivity of the NBR at different voltages (1, 2.5, 5)kV was studied in this paper. The results obtained showed an increase in electrical resistance with increased PVC content. Interestingly, a voltage, i.e. electric field dependence was also observed. The field dependence is the highest in case of lowest test voltage (1kV).

The microwave initiated polycondensation is a new approach for polylactic acid production. The time need of this process is quite less compared to the standard polycondensation process, but the progress and improvement of the molar mass is the most important basic factor.

In my earlier work the standard polycondensation has already been investigated, so to be able to compare both methods PLLA has been produced by microwave initiated polycondensation too. The measurement of molar weights is a crucial point of polymer synthesis. According to my earlier work a rheology-based method was used again to define the molar masses during the polymerization process and make the comparison reliable.

During my experiments PLLA has been synthesized by microwave initiated polycondensation method. According to the relevant literature, by standard polycondensation 10⁴-10⁵ g·mol⁻¹ molar mass can be reached, so the main question was that how long should be the microwave process run to result the same level of molar mass. During the experiments PLLA samples have been taken according to a special time plan, then solved in chloroform prepared samples with different concentrations for further analysis. To measure the flow-times Ubbelohde capillary viscometer was applied at this time too. Based on the data of viscometry measurements the intrinsic viscosities have been graphically defined then the molar masses of polylactic acid polymers were calculated according to the correlation of Mark – Houwink relation.

In this work the results of studying of the mechanical behaviour of metal-ceramic composites with an aluminium matrix on meso-scale level are submitted. Computer simulation of mechanical reaction of representative volume of composite material, considered as ensemble of the interacting structural elements (ceramic particles and metal matrix), is used for studying mechanisms of deformation on meso-scale level of metal-ceramic composites under the loading by shock waves. The mechanical behaviour of aluminium matrix is described by the model of the damaged elastic-plastic medium. The model of the damaged brittle solid is used for ceramics. The absence of macroscopic and mesoscopic voids and cracks in the material before loading is assumed. Ideal adhesion of ceramic material to metal is supposed at the initial condition. The problem is solved in 2D statement with application of finite-difference method. Results of numerical simulation of the mechanical behaviour of metal-ceramic composites under shock wave loading have shown the formation of non-stationary and essentially non-uniform fields of stresses and strains at the meso-scale level. The generation of a dissipative structure on the meso-scale level of the composites under shock wave loading was revealed in the simulations.

In this article will present the technology parameters effects in the case of thin copper sheets joining with agree of the material science theory and metalworking rules-based executed experiments. Known the dislocation theory of the ultrasound energy influence in the case of the metalworking. The ultrasonic welding technology uses the ultrasound effect for increase the metal formability because the joint established by high-frequency vibration and pressing. The ultrasonic welding is a solid-state welding technology in which detectable the high-frequency vibration caused friction effected warming in the joint and the heat-affected zone. The established heat accompanied by plastic deformation can cause Changement in the joint microstructure as a function of the established heat, the heat transfer coefficient and the plastic deformation degree of the used metal. The relationship is founded between the experimented metal thin sheets welded joint mechanical properties, microstructure and the welding parameters. The joint mechanical and microstructural properties experimented by Vickers hardness test and visual inspections.

The phenomenon of material fracture spans many different length scales. The paper is devoted to the numerical investigation of the features of fracture processes in alumina-zirconia composite ceramics at the mesoscale subjected to uniaxial compression. A structural model of the composite mesovolume based on the experimental SEM image is adopted. The mechanical behavior of the composite is described by a constitutive model of the damageable elastic-brittle medium. Two local fracture criteria are used that are based on the limit values of damage and tensile pressure. The energy dissipation process in the ceramic composite mesovolume during damage accumulation is analyzed. It is shown that the damage accumulation results in nonlinear dissipation of potential energy and the following kinetic energy increase. The last is accompanied by the appearance and growth of cracks in matrix and inclusions at the final stages of deformation.

The article presents the model of intervertebral disc, that takes into account the presence of a nucleus pulposus and an annulus fibrous containing collagen fibers with direction at angles ±45º and ±30º. The influence of the percentage of layers of the annulus fibrous with different directions of collagen fibers on the stress-strain state of the intervertebral disc was investigated.

The flow behaviors of different poly (vinyl chloride) and corncob flour composite were characterized using a Göttfert 20 extrusion rheometer. The rheological characterization includes extrusion experiments at different temperatures and screw speeds. By evaluation of flow rate and die pressure the flow properties and the activation energy of the flow can be determined. This also provides insight into the internal structure/organization of the prepared composite and gives information about process ability and processing window parameters. The flow of the melt is mostly determined by the molecular weight of the polymer but for PVC the higher organization of the polymer as tertiary and quaternary structures have also a significant effect. Moreover, the molecular weight affects not only the viscosity but also the relaxation times. This flow behavior of the polymer has changed significantly by shearing time and thermal history of the materials. PVC composites compounded from raw PVC powder of various K–values (molecule weight) were prepared and examined via a complete rheological analysis. The PVC composite's morphology mostly depends on the concentration of the components, the material matrix and the corncob additive. The viscosity of the composites, the Rabinovich exponent, and flow-viscosity curves were determined in this paper. The results of the rheological tests can help us to make comprehensive conclusion about the composite structures, processing possibilities and applicability.

The cobalt depleted layer of WC–Co composite materials was investigated after selective cobalt etching in diluted Caro's acid. The time dependence of Co etching and the thickness of the etched layer was determined by using Glow Discharge Optical Emission Spectrometer (GD-OES) depth profiling as well as by calculation method based on determination of the dissolved Co by Atomic Absorption Spectrophotometric (AAS) measurement. The integrity of the modified outermost layer of the WC–Co composite materials were qualified using Rockwell C indentation test. This test methods were found usable for optimisation of the pre-treatment applied before the diamond thin film deposition.

The localized plasticity development was studied for a wide range of pure metals and alloys in single-crystal and polycrystalline state as well as nonmetallic materials, alkaline halide crystals, ceramics and rocks. Using photographic and digital versions of speckle photography, the localization of plastic flow in the test samples was investigated on specially designed units having high spatial and temporal resolution. According to the analysis given here, the different stages of plastic flow are related both qualitatively and quantitatively.

Si ion implantation into SiO₂ is widely used to synthesize specimens of SiO₂ containing supersaturated Si. We also prepared specimens of supersaturated Si in SiO₂ by reactive pulsed laser deposition (PLD) in an oxygen atmosphere. After high temperature annealing of these specimens induces the formation of embedded luminescent Si nanocrystals in SiO₂. In this work, the potentialities of excimer UV-light (172 nm, 7.2 eV) irradiation and rapid thermal annealing (RTA) to enhance the photoluminescence and to achieve low temperature formation of Si nanocrystals have been investigated. The Si ions were introduced at acceleration energy of 180 keV to fluence of 7.5 x 10¹⁶ ions/cm². We also prepared Si nanocrystals embedded in a SiO₂ by reactive pulsed laser deposition (PLD) in an oxygen atmosphere by using conventional PLD system with 2nd-harmonic YAG laser (532 nm, 10 Hz, 80 J/cm²) under controlled low oxygen pressure. Samples were subsequently irradiated with an excimer-UV lamp. After the process, the samples were rapidly thermal annealed before furnace annealing (FA). Photoluminescence spectra were measured at various stages at the process. We found that the luminescence intensity is enhanced with excimer-UV irradiation and RTA. Moreover, effective visible photoluminescence is found to be observed even after FA below the annealing temperature at 1000 °C, only for specimens treated with excimer-UV lamp and RTA. We will make clear the similarities of photoluminescence with the way of preparation techniques.

ZrC-TiC-MoSi₂ ceramic composite was consolidated by spark plasma sintering at 1850-1900°C temperature, for 5-10 min of dwell time under 50 MPa of applied pressure. The influence of MoSi2 addition on the mechanical performance and microstructure of ZrC-TiC composite was investigated. Compared with ZrC-TiC, the sinterability of ZrC-TiC-MoSi₂ was improved, as the latter one achieved relatively fully dense bulk under the same sintering conditions. The hardness and fracture toughness of ZrC-TiC-MoSi₂ composite were increased remarkably manifesting >99% of density, 29.8 GPa of Vicker's hardness, and indentation fracture toughness of 8.01 MPa·m^1/2. Under erosion and fracturing conditions, it was shown that solid solutions of (Zr,Ti)C serve an important role in erosion and crack propagation resistance.

In this research, alumina-zeolite composite materials were synthesised by mechanical activation and oxidation sintering technique. A comprehensive examination of the microstructure of the starting raw materials and the sintered ceramic specimens have been studied via X-ray diffraction (XRD) and scanning electron microscopy (SEM). Moreover, several properties were investigated such as volume shrinkage, density, porosity, weight loss and water absorption based on the compositions of the composite specimens, sintering temperature, and microstructure. The authors have found that the raw material compositions and the sintering temperature have great influence in the microstructure and the characteristic of the final prepared ceramic specimens.

Additive materials are the perfect solutions to improve the physical, mechanical and expansion properties of lightweight expanded clay aggregates (LECA). This work focused on studying the effect of bentonite materials on physical, mechanical, expansion properties and mineral phases of expanded clay aggregates. Samples were collected from Mályi quarry Miskolc, Hungary. These samples were studied by XRF, XRD, SEM and heating microscope. In addition, the physical and mechanical properties of specimens were measured according to relating standards. Results showed that, addition of bentonite material to the clay samples has great effect on bulk density, sintering and melting point and compressive strength of the aggregates. By using the three different amounts (5 %, 10 % and 20 %) of bentonite with the LECA, compressive strength of the aggregates was enhanced by 48 % to 112 % compared to aggregates without bentonite. 10 % of bentonite with aggregates was enhanced the height expansion of the aggregates by 50–68 %. In addition, 10 % of bentonite with LECA was most crucial, which decreased bulk density of aggregates by 5 % to 20 % compared with other added amounts of bentonite. According to XRD analysis, hercynite was one of the phases, which can control compressive strength of aggregates.

In recent years, the sol-gel synthesis of porous glasses has drawn widespread attention owing to the convenience and versatility of the sol-gel method. The sol-gel synthesis process mainly involves hydrolysis and condensation of precursors followed by drying and stabilization. In the present study, silica-titania (Si-Ti) based porous glasses with different compositions were synthesized using the sol-gel method. In general, the final properties of solgel derived glasses significantly depend on the characteristics such as pore structure, pore size, morphology and the compositions of the precursor materials. The influence of these processing parameters on the microstructural and thermal properties of Si-Ti based glasses has been investigated. The microstructures of the synthesized Si-Ti based porous glasses were investigated using scanning electron microscopy (SEM) and the thermal properties were evaluated using thermogravimetric analysis (TGA) and thermomechanical analysis (TMA). The main objective of the present study is to utilize these Si-Ti porous glasses as a potential biomaterial for bone tissue regeneration. Therefore, to understand this facet of Si-Ti porous glasses, it is essential to investigate their physical and microstructural properties.

Nowadays stricter energy regulations are compelling us to further improve the thermal insulation performance of current building materials. In this study we investigated the possibility of improving the thermal insulating performance of fired clay bricks. In our work we used two types of additives: sawdust, which is a general additive, and expanded perlite, which is typically a synthetic additive based on SiO₂ and Al₂O₃. Sawdust and expanded perlite in amounts varying between 3.35-6.5 wt% were mixed into a clay masses to prepare test samples by pan mill. The moisture content of the clay masses was 25 wt%. Samples were prepared using a laboratory vacuum extruder, after which they were dried, and then sintered at 880 °C. The fired specimens were measured for firing shrinkage, water absorption, bulk density, and compressive strength. Furthermore, we determined the thermal conductivity of the specimens. The purpose of our research was to examine the usability of expanded perlite as an additive in brick manufacturing, and also to compare the results with sawdust, one of the most popular additives. In addition, measurements were made using the two additives together.

Si-B alloys are considered as phase change materials (PCMs) in the thermal energy storage (TES) systems due to their high latent heats and moderate temperatures. In order to successful apply them, proper Si-B alloy composition and a suitable ceramic refractory material that can survive long time corrosion at high temperatures should be determined. Here, we investigate serials of Si-B alloys with the B range of 2-11 mass % in graphite crucibles in the temperature range 1450-1750 °C. This work shows that the interaction between Si-B alloys and graphite goes into two stages. Single SiC is formed at the interface at the B content of 2 mass %. SiC and B₄C are produced at the interface at the B contents of higher than 5 mass %. Additionally, the results of structural characterization are supported by thermodynamic calculation. These results provide reliable data in the use of Si-B alloys as PCMs in the TES systems.

Using relatively low-cost raw materials (conventional kaolin and sawdust powders) and simple technology, the authors have developed new ceramic composite materials which can successfully meet different industrial requirements. Casting masses (slurries) were made by mixing and milling different compositions of the powders with distilled water. The ceramic specimens were made by conventional gravitation slipcasting method, after drying of the green specimens, the samples were sintered in an electric kiln under oxidation and reduction atmosphere at 1250°C. The prepared and sintered specimens were tested based on geometrical sizes, microstructures and morphologies using scanning electron microscopy. In this work, the authors present some parts of the results of their research and investigation.

Hydrogels, due to their unique properties (they can absorb large amounts of solution, sometimes even several hundred times higher than their initial mass), have found application in many areas of life. Their polymerization rate depends for example on the pH, temperature, composition of the polymerization mixture, amount of the initiators, degree of cross-linking of the polymer and composition of the polymerization mixture.

The results of the kinetic reactions showed that the increased proportion of silicate in the sample causes faster gelation. It was also found that the lower the silicate modulus is, the polymerization reaction starts faster. However, oscillation tests carried out 24 hours after synthesis showed that better elastic properties (higher values of the elastic modulus G') show samples with higher content of polymer in the composition.

Carbon is abundantly found in nature with a wide range of applications. It can be synthesized through physical and chemical processes. Chemical activation is considered as a very efficient method to obtain carbon with high surface area and narrow micropore distribution. Among all the chemical activating agents, alkaline hydroxides such as potassium hydroxide (KOH) or sodium hydroxide (NaOH) are reported to be of high interest in the production of carbon with higher performance. In our research, Nettle stem and peanut shell (natural materials) were used as raw materials for the preparation of carbon. Natural structures of nettle and peanut shell consists of cellulose, which is an important precursor in the preparation of highly ordered carbon nanosheets. Aqueous solutions of KOH and NaOH were used for activation and sulphuric acid (H₂SO₄) was used for exfoliation. The process employed here has yielded a high percentage of carbon nanostructured particles.

Increasing the energy efficiency of buildings has become very pertinent currently. This will be implemented by employing eco-friendly materials such as foam glass. Glass foaming is a process that depends strongly on the foaming mechanism and the initial composition of the mixture. This study deals with the investigation of foam glass properties consisting of recycled bottle glass material, CRT glass and aluminium dross. Experiments were carried out to investigate the thermal behaviour, optimal foaming temperature, density, water absorption, thermal conductivity and compressive strength of the foams. Microstructure and cell size distribution was analyzed as well. Effect of the CRT glass and the aluminium dross on the properties of the foams was evaluated in this paper. Adding aluminium dross decreased the foaming temperature, increased the foaming height and enhanced the compressive strength of the foam glass.

Silicon carbide (SiC) powder was added to a polyurethane elastomer (PUR) to produce the composites. PUR was synthesized by mixing polyether polyol (PETP, M_w = 6000 g/mol) and 4,4'diphenylmethane diisocyanate. The stress-strain curves were carried out to estimate the effect of SiC on rubber elastic behaviour of PUR composites. As SiC content increases, the rubber elasticity region is noticeably decreased which can clearly be seen in the stress-strain curve, this could be attributed to the distribution of the SiC particles in the PUR matrix which prevents the cross-linking chain mobility of PUR and therefore affects the deformation while stretching. Furthermore, the decrease in the elongation at break is also co-related to the SiC content which hindrance the molecular mobility of the PUR chain. Shore A and D hardness increase by increasing SiC content up to 88 Shore A and 37 Shore D at 30 wt.% SiC. This is mainly due to the addition of SiC particles which act as active fillers in PUR matrix. The tensile strength and Young's modulus are slightly increased when SiC content was increased. These observations support that Sick particles act as reinforcement which is active fillers and affect the stiffness in the elastic deformation of PUR.

Silica sand is the most commonly used mineral for molding and core making applications in foundry technology due to its availability, thermal and chemical attributes. However, there are many additional requirements foundry sands need to meet regarding their sizing, chemical purity, physical durability and thermal properties. This research studies the thermophysical properties of a foundry silica sand comprehensively. After separating one sand batch into numerous grain size ranges, the chemical composition and thermophysical properties of the fractions were investigated, respectively. By means of this approach, the chemical properties and thermal behavior can be directly linked. The silicon dioxide content shows a strong correlation with the thermal expansion properties of the various fractions. The results give a better understanding of the high temperature behavior of foundry silica sands and clarify the role of factors affecting their thermophysical properties.

This work reports the various influences on the formation of silica-encapsulated liposome particles such as the used concentration of silica precursor and lecithin, and reaction temperature, and used solvent, and demonstration of cosmetic application with natural hemp-seed extracts as an anti-oxidant material for controlled release formulation. The obtained SLPs from various conditions were characterized by SEM, particle size analyzer, and FT-IR spectrophotometer to confirm the morphology and particle size. Furthermore, the cosmetic formulation of SLPs was demonstrated with controlled release of natural hemp-seed extracts.

In this study, 100% recycled glass foam granules obtained from waste glass were tested as a lightweight concrete aggregate (LWA). The characteristics of the raw materials used, grain-size distribution, bulk density, self-strength, frost resistance, chemical composition and the morphology of foam glass were examined. Subsequently, a series of concrete mixes were proportioned with water-to-cement ratios (w/c) of 0.4 with 0-30 wt%. Foam glass granules and probe cubes were formed. The mechanical and physical properties of concrete samples, such as compressive strength, density, water absorption, and thermal conductivity were tested. In addition, compressive strength values were compared with lightweight concrete specimens containing the same amount of Liapor aggregates. The results showed that foam glass increased concrete's thermal insulation and density, and also decreased its water absorption. However, it significantly decreased its strength properties.

The shortage of oil and related minerals and also their extreme environmental drawbacks are the main reason for the quick-growing interest in biodegradable polymer composites production. Biodegradable polymer composites are mainly produced from renewable resources which are biologically degradable. In this research, corn starch was plasticized with glycerol. The plasticized thermoplastic corn starch was reinforced with calcium carbonate precipitate powder as a filler and pine wood fibre as reinforcement. Free thermoplastic plasticized corn starch (FTPS), thermoplastic corn starch reinforced with calcium carbonate (CTPS), thermoplastic corn starch reinforced with pine wood (WTPS), thermoplastic corn starch reinforced with pine wood fibre and calcium carbonate precipitate hybrid composite (HTPS) were produced and compared for their mechanical properties like tensile strength and, hardness. DSC and DMA analysis were also done for determining their thermal properties. Moreover, the water absorption test was also carried out to understand their resistance to moisture. WTPS exhibits better results in most of the measured proprieties given that TPS and wood fibre being both hydrophobic resulted in a homogeneous distribution and better interfacial adhesion.

In this study the preparation of pure and Bismuth (Bi) doped barium titanate (BaTiO₃) nanoceramics by sol-gel process is reported. The structural and optical properties of the samples were investigated using X-ray diffraction (XRD) and UV-visible spectroscopy. XRD results show that the samples are crystallized in the pure perovskite structure when calcined at relatively low temperature (800 °C) for 3 h, without the presence of secondary phases. Both Bi doping (1%, 2%) decrease the lattice parameters, tetragonality and the crystallite size. The decrease of their sizes can be explained by the replacement of large ionic radii of Ba²⁺ (1.35Å) ion by smaller ionic radii Bi³⁺ (1.03 Å) ion. A close investigation of the results shows that BT is a tetragonal-phase ferroelectric. The band gap of the Bi-doped BaTiO₃ nanopowders is lower compared to that of pure BaTiO₃, as determined from the analysis of UV absorbance spectra.

Changes in the specific surface, pore size and content of Lewis (siloxane) and Brønsted (silanol) surface groups for high-silica nanoporous glass with a sponge-corpuscular structure depending on their thickness and storage time are studied and interpreted in terms of porous structure features, hydration and aging effects.

Lightweight concrete has been known all around the world for decades. As a masonry material, there is an advantage: it has sufficient mechanical strength despite of its light weight. This research focuses on the production of recycled concrete based lightweight geopolymer concrete samples using glass foam aggregates. During the research geopolymer and concrete samples were made and finally their properties were investigated and compared. In the research work an alkaline silicate reaction (ASR) was also studied on the glass foam lightweight aggregates, which is very important for concrete failure. Material structural and morphological tests were obtained by scanning electron microscopy (SEM) to characterize the geopolymer concrete samples. Compressive strength of lightweight concrete and lightweight geopolymer was determined at the age of 7 days. Glass foam is suitable for use as a lightweight aggregates for workability. Based on the 7 days compressive strength results no crust typical of the ASR reaction was detected on the surface of the mixtures.

Silica–titania mixed oxides and composites have been extensively studied, whereas to the titanium monoxide (TiO) –silicon monoxide (SiO) counterparts has been devoted very little attention. Laser ablation of SiO and TiO in liquids is in according with literature completely unexplored. Here we report on Nd:YAG pulse laser ablation of SiO and TiO in ethanol which allows generation of SiO- and TiO-based nanoparticles and their agglomerates.

Mixed SiO-TiO colloid has been prepared by simple mixing of ablatively prepared individual colloids in 1:1 volume ratio. Measurement of size distribution by Dynamic Light Scattering (DLS) determines sizes of 24.85 nm and 262.3 nm for SiO colloid, 494.8 nm for TiO colloid and 35.2 nm and 397.5 nm for mixed colloid. Zeta potential values suggest incipient instability for all measured systems. Morphology of the particles captured on Ta substrate by evaporation of ethanol was studied using Scanning Electron Microscopy (SEM). Round-shaped, oval, and sheet-like particles and their agglomerates have been observed. Raman spectroscopy of the mixed SiO-TiO colloid revealed multiphase structure consisting of anatase and/or rutile, crystalline and amorphous silicon and silica and crystalline and amorphous titanium silicide TiSi₂. Formation of TiSi₂ demonstrates unexpected low temperature disproportionation of SiO and TiO-based species and mutual reducing interactions. Catalytic activity of individual SiO and TiO colloids and of their mixture has been tested in terms of methylene blue (MB) degradation under the daylight. TiO-SiO mixture exhibits higher solar-light catalytic activity compared to individual colloids which could by explain by the presence of highly photocatalytic TiSi₂. These results represent potential of SiO and TiO reducing interactions which are favorable for generation of photocatalytic materials for water remediation.