Iris Publishers Journal Of Engineering Sciences

Global Journal of Engineering Sciences Thermogravimetric analysis (TGA) is one of the most popular analysis techniques to study the decomposition process of polymeric materials in controlled atmospheres at various temperatures. In this review, dynamic TGA was carried out to determine the thermal stability of the recycled epoxy-based and vinyl ester-based carbon fiber composite (CFC). The specimens were heated from ambient to 800°C under nitrogen and air at different heating rates. Results indicates that different heating rates has no significant influence on the degradation of the epoxy-based CFC. For More Open Access Journals in Iris Publishers Please Click on: https://irispublishers.com/ For More Articles in Global Journals of Engineering Sciences : https://irispublishers.com/gjes/

Global Journal of Engineering Sciences MVG (micro vortex generator) is a potentially new device which can alleviate or overcome the adverse effects of SBLI (Shockboundary layer interaction) and improve the “health” of the boundary layer. In this paper, the SBLI in a ramp flow with MVG under different inflow conditions is investigated by LES (large eddy simulation). Three turbulent inflows with different boundary layer thickness are generated based on turbulent profiles obtained from DNS (Direct numerical simulation) of transition. The numerical results show that the interaction between ring-like vortices generated by MVG and the ramp shock is influenced by these different inflow conditions. With lower boundary layer thickness, the ring-like vortices are less distorted and thus more stronger when they travel to the ramp corner. The more regular and stronger ring-like vortices have more capability to eliminate or distort the strong ramp shock wave. Moreover, it confirms th...

Global Journal of Engineering Sciences The aim of this study is to characterize the technical properties of Bigadic Boron Works Waste Clay (BWC) fired at various temperatures. For this purpose, the clay sample was first characterized by chemical and X-ray diffraction (XRD) analyses. The mineralogical composition of BWC was composed of ulexite, smectite, illite, quartz, calcite and magnesite phases. To evaluate technological behaviors, pressed clay samples were fired separately at temperatures between 900, 950 and 1000° C. Fired specimens were evaluated by water absorption, linear shrinkage, bending strength, scanning electron microscopy (SEM) and color measurements. The results showed that there became a significant densification at temperatures especially above 950° C. Based on the technological characteristics, BWC could be used as an additive raw material in the manufacture of structural ceramics. For More Open Access Journals Please Click on: https://irispublishers.com/...

Global Journal of Engineering Sciences Based on the critical conditions for nucleation and the actual eigenstrain of a given shape memory alloy in the stress induced martensitic phase transformation, the closed-form expression of its corresponding initial yield (nucleation) surface is obtained. Consequently, the underline mechanism for non-symmetry in the stress vs. strain relationship between uniaxial tension and uniaxial compression experimentally observed in many SMAs is revealed. Unlike that in many traditional criteria, such as the Von Mises and Tresca criteria, in which the yield surfaces are functions of stress only, the yield surface derived here is closely related to the crystal structures before and after the phase transformation. The initial yield surface of a polycrystalline CuZnAl shape memory alloy tube under combined loading of tension and torsion predicted by the formula developed here agrees well with the experimental results reported in the literature. ...

Global Journal of Engineering Sciences In our previous paper [1], a constitutive model was developed for the stress-induced martensitic transformation and reorientation in single crystalline shape memory alloys. The critical condition and evolution equation for the phase transformation and reorientation were proposed. In this paper, the model proposed in our previous paper [1] is applied to simulate the behavior of stress-induced phase transformation in a CuZnAl single crystal and reorientation between CuAlNi martensite lattice correspondence variants. It is found out that the prediction results are consistent with the experimental data reported in the literature. For More Open Access Journals Please Click on: https://irispublishers.com/ Foe More Articles in  Global Journal of Engineering Sciences : https://irispublishers.com/gjes/

Global Journal of Engineering Sciences This paper aims, firstly, to provide an investigation of plasma jets dynamics by the help of the Lattice Boltzmann method (LBM) and second to test the computational efficiency of the LB method by comparison of its results to former measurements and numerical findings. The plasma gas is the argon injected at 520 m/s and 13500 K. In this study we accounted for highly variable thermophysical properties dependence on temperature. The LB results using the proposed model seems to give an excellent compromise between former experimental and numerical results using classical methods (FDM, FVM), while the deviations were found with other simulations attempts by the LB method. For More Open Acce ss journals Please Click on : https://irispublishers.com/ For More Articles in Global Journal of Engineering Sciences : https://irispublishers.com/gjes/

Global Journal of Engineering Sciences A Big Data Platform (BDA) with Hadoop/MapReduce technologies distributed over HBase (key-value NoSQL database storage) and generate hospitalization metadata was established for testing functionality and performance. Performance tests retrieved results from simulated patient records with Apache tools in Hadoop’s ecosystem. At optimized iteration, Hadoop distributed file system (HDFS) ingestion with HBase exhibited sustained database integrity over hundreds of iterations; however, to complete its bulk loading via MapReduce to HBase required a month. The framework over generated HBase data files took a week and a month for one billion (10TB) and three billion (30TB), respectively. Apache Spark and Apache Drill showed high performance. However, inconsistencies of MapReduce limited the capacity to generate data. Hospital system based on a patient encounter-centric database was very difficult to establish because data profiles have complex r...

Global Journal of Engineering Sciences The aim of this work is to optimize the design and performance of solar powered γ Stirling engine based on genetic algorithm (GA). A second-order mathematical model which includes thermal losses coupled with genetic algorithm GA has been developed and used to find the best values for different design variables. The physical geometry of the γ Stirling engine has been used as an objective variable in the genetic algorithm GA to determine the optimal parameters. The design geometry of the heat exchanger was considered to be the objective variable. The heater slots height, heater effective length, cooler slots height, cooler effective length, re-generator foil unrolled length and re-generator effective length are assumed to be the objective variables. Also, three different types of working fluids have been used in the model simulation to investigate the effect of the different working fluid on the engine performance. The comparison between ...