In the last 30 days

• Open/close Evaluation of corrosion resistance of casting magnesium alloy AZ31 in NaCl solutions

  J Przondziono et al 2011 IOP Conf. Ser.: Mater. Sci. Eng. 22 012017 Tag this article

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  The results of tests of corrosion resistance of casting magnesium alloy AZ31 in NaCl solutions of 0,01÷2 M concentration have been presented. Electrochemical measurements were carried out with application of VoltaLab®PGP201 system by Radiometer. On the ground of registered polarisation curves, typical features characterising alloy resistance to electrochemical corrosion, i.e. corrosion potential, polarisation resistance, corrosion current density and corrosion rate, were determined. Electrochemical impedance spectroscopy was applied for evaluation of phenomena that occurred on the surface of the tested alloy. Resistance to corrosion was tested by means of immersion method for 1÷5 days. By means of scanning electron microscope with field emission FE SEM S-4200 Hitachi in cooperation with spectrometer EDS Voyager 3500 Noran Instruments, quantitative and qualitative analysis of chemical composition in micro-zones was made. The study also presents the results of measurements of geometrical features of AZ31 alloy surface after corrosion tests. The results of the tests show undoubtedly deterioration of corrosion properties of magnesium alloy AZ31 together with the increase in molar concentration of NaCl solution.

• Open/close Finite element analysis of composites materials for aerospace applications

  M Nurhaniza et al 2010 IOP Conf. Ser.: Mater. Sci. Eng. 11 012010 Tag this article

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  Composites materials are intended to be used more extensively as an alternative of aluminum structure in aircraft and aerospace applications. This is due to their attractive properties as high strength-to-weight ratio and stiffness-to-weight ratio. Besides that it clarifies the growing interest for composites materials due to advantages of lightweight, high strength, high stiffness, superior fatigue life, tremendous corrosion resistance and low cost manufacturing. In this study, a finite element analysis (FEA) of fiberglass unidirectional E-type was analyzed in the framework of ABAQUS finite element commercial software. The analysis was done to quantify the mechanical properties and response of unidirectional E-glass in term of tensile, compression and thermal responses. From the analysis, the maximum and minimum values of stress and strain for E-glass 21xK43 Gevetex and Silenka E-glass 1200tex were obtained and stress-strain curve is presented. The ultimate load of failure, elastic behavior, tensile strength and other properties for each laminated plates under tensile and thermal-stress are determined from stress-strain curves. The simulation will run twice for each material where the first simulation based on orientation angles of 45° for ply-1, -45° for ply-2 and 90° for ply-3 while the second simulation, the orientation angles is 0° for all plies. The simulation is successfully conducted and verified by experimental data.

• Open/close Characterization of poly(ethylene terephthalate) used in commercial bottled water

  Cristina Bach et al 2009 IOP Conf. Ser.: Mater. Sci. Eng. 5 012005 Tag this article

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  The aim of this study is to determine which compounds are present into drinking water packaged in poly(ethylene terephtalate) bottles and to know the origin of these substances in relationship with the material.

  A screening procedure was established for the detection of unknown compounds into bottled water. A panel of water bottles has been tested after exposure to extreme conditions of temperature and UV radiation to accelerate the possible migration of substances.

  At the same time, physico-chemical characterization of polymeric material has been performed namely calorimetric analysis, IRTF and low-frequency mechanical spectroscopy. The results thus obtained allow understanding in a better way the migration kinetics of molecules inside the polymer, it means the pollution of the bottled water.

• Open/close Effect of Soft Story on Structural Response of High Rise Buildings

  F Hejazi et al 2011 IOP Conf. Ser.: Mater. Sci. Eng. 17 012034 Tag this article

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  Severe structural damage suffered by several modern buildings during recent earthquakes illustrates the importance of avoiding sudden changes in lateral stiffness and strength. Recent earthquakes that occurred have shown that a large number of existing reinforced concrete buildings are vulnerable to damage or even collapse during a strong earthquake. While damage and collapse due to soft story are most often observed in buildings, they can also be developed in other types of structures. The lower level containing the concrete columns behaved as a soft story in that the columns were unable to provide adequate shear resistance during the earthquake. Usually the most economical way of retrofitting such as a building is by adding proper bracing to soft stories. So, in this paper occurring of soft at the lower level of high rise buildings subjected to earthquake has been studied. Also has been tired to investigate on adding of bracing in various arrangements to structure in order to reduce soft story effect on seismic response of building. It is lead to assess the vulnerability level of existing multi-storied buildings so that they can be retrofitted to possess the minimum requirements. This will help in minimizing the impending damages and catastrophes.

• Open/close Mechanical properties of kenaf bast and core fibre reinforced unsaturated polyester composites

  M R Ishak et al 2010 IOP Conf. Ser.: Mater. Sci. Eng. 11 012006 Tag this article

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  Kenaf fibre has high potential to be used for composite reinforcement in biocomposite material. It is made up of an inner woody core and an outer fibrous bark surrounding the core. The aim of this study was to compare the mechanical properties of short kenaf bast and core fibre reinforced unsaturated polyester composites with varying fibre weight fraction i.e. 0%, 5%, 10%, 20%, 30% and 40%. The compression moulding technique was used to prepare the composite specimens for tensile, flexural and impact tests in accordance to the ASTM D5083, ASTM D790 and ASTM D256 respectively. The overall results showed that the composites reinforced with kenaf bast fibre had higher mechanical properties than kenaf core fibre composites. The results also showed that the optimum fibre content for achieving highest tensile strength for both bast and core fibre composites was 20%wt. It was also observed that the elongation at break for both composites decreased as the fibre content increased. For the flexural strength, the optimum fibre content for both composites was 10%wt while for impact strength, it was at 10%wt and 5%wt for bast and core fibre composites respectively.

• Open/close Nanocrystalline Zeolite Y: Synthesis and Characterization

  Niken Taufiqurrahmi et al 2011 IOP Conf. Ser.: Mater. Sci. Eng. 17 012030 Tag this article

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  Nanocrystalline zeolite has received significant attention in the catalysis community. Zeolites with a crystal size smaller than 100 nm are the potential replacement for existing zeolite catalysts due to its unique features with added advantages. Zeolite FAU type Y is one of the most studied framework of all zeolites, and has been used as catalysts for number of reactions in the refinery and petrochemical industry. The present paper covers the synthesis of nanocrystalline zeolite Y under hydrothermal conditions from clear synthesis mixtures. The crystal size of zeolite Y is influenced by temperature, aging time, alkalinity, and water content. The synthesized Y is characterized by X-ray diffraction (XRD), Fourier Transmission Infrared Sprectroscopy (FTIR), Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM) and Nitrogen Adsorption.

• Open/close Hot cracking of welded joints of the 7CrMoVTiB 10-10 (T/P24) steel

  J Adamiec 2011 IOP Conf. Ser.: Mater. Sci. Eng. 22 012001 Tag this article

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  Bainitic steel 7CrMoVTiB10-10 is one the newest steels for waterwalls of modern industrial boilers [1]. In Europe, attempts have been made to make butt welded joints of pipes made of this steel of the diameter up to 51 mm and thickness up to 8 mm. Many cracks have been observed in the welded joint, both during welding and transport and storage [2-4]. The reasons of cracking and the prevention methods have not been investigated. No comprehensive research is carried out in Europe in order to automate the welding process of the industrial boiler elements made of modern bainitic steel, such as 7CrMoVTiB10-10. There is no information about its overall, operative and local weldability, influence of heat treatment, as well as about resistance of the joints to cracking during welding and use. The paper presents experience of Energoinstal SA from development of technology and production of waterwalls of boilers made of the 7CrMoVTiB 10-10 steel on a multi-head automatic welder for submerged arc welding.

• Open/close Synthesis of Monolithic β-Sialon Powders (Si_6−zAl_zO_zN_8−z, Z = 2−4) through Controlling the Combustion Reaction Temperature

  Mohammed Shahien et al 2011 IOP Conf. Ser.: Mater. Sci. Eng. 18 072003 Tag this article

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  Pure β-sialon powders with the controlled z values ( z = 2− 4) were successfully prepared from stoichiometric mixtures of constituent elements (Si, Al and SiO ₂) under a nitrogen pressure of 1 MPa by the combustion synthesis (CS) method. The raw materials were combusted with different ratios of a commercial sialon powder of z = 1 as a diluent (0, 10, 20, 30, 40, 50 wt %). Without diluent, the reactions temperatures were very high (> 2000 °C) and the product contained metal Si residue besides Sialon products. The combustion temperatures of nitridation reactions were controlled by using Sialon ( z = 1) as a diluent. The combustion reactions completed at 50 wt% dilution, and pure β-sialon phases were synthesized. However, the individual peaks of β-Sialon ( z = 1) diluent were also detected. Single-phase β-sialon powders were obtained by using the products as diluents and repeating the combustion for few times.

• Open/close Improvement of Strength and Oxidation Resistance for SiC/graphite Composites by SiC coating

  Wanli Yang et al 2011 IOP Conf. Ser.: Mater. Sci. Eng. 18 022013 Tag this article

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  SiC/graphite composites with exelent machinable properties and thermal shock behaviour were successfully fabricated by pressureless sintering at 1700°C in nitrogen atmosphere. A dipping infiltration process was applied to improve the strength and oxidation resistance of the composites. Dense SiC coating was covered on the composites' surface by heat-treating at 1400°C in nitrogen atmosphere with dipping infiltration of silica sol and phenolic resin solutions. The flexural strength of the SiC coated composites were improved from 60 MPa to 140 MPa obviously, and the weight loss of the SiC coated composites was reduced more than 20 % comparing with the uncoated composites by oxidation resistance testing at 1000 °C for 24 h in air. SEM micrographs shows that SiC coating was surrounded the surface of pores and XRD pattern revealed that the new layer was SiC.

• Open/close Artificial photosynthesis - CO₂ towards methanol

  D Nazimek and B Czech 2011 IOP Conf. Ser.: Mater. Sci. Eng. 19 012010 Tag this article

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  The new insight into the problem of carbon dioxide utilization into valuable compound – methanol and then its transformation into fuel is presented. Because the highly endothermic requirements of the reaction of CO ₂ hydrogenation a photocatalytic route is applied. Combining of the two reactions: water splitting and CO ₂ hydrogenation using H ₂O as a source of hydrogen at the same time and place are proposed. The studies over modified TiO ₂ catalysts supported on Al ₂O ₃ were conducted in a self-designed circulated photocatalytic reaction system under at room temperature and constant pressure. Experimental results indicated that the highest yield of the photoreduction of CO ₂ with H ₂O were obtained using TiO ₂ with the active anatase phase modified by Ru and WO ₃ addition. The conversion was very high – almost 97% of CO ₂ was transformed mainly into methanol (14%vol.) and into small amount of formic and acetic acid and ester.