Numerical investigation of thermal disassociation of ZnO for hydrogen production: Parametric study and reactor configuration

The present research is focused on the two‐step ZnO/Zn thermochemical water splitting cycle for hydrogen production. In the present paper, the numerical modeling of the first step, which involves endothermic reduction of zinc oxide (ZnO), is carried out in a cylindrical reactor using Computational Fluid Dynamics (CFD). The parametric study shows that the fractional conversion of ZnO increases with an increase in the flow rate of ZnO, while it decreases with an increase in the ZnO particle diameter and carrier gas mass flow rate. Six different reactor configurations are also assessed comprehensively. It is observed that a cylindrical reactor with a tangential inlet at the top plane and a tangential outlet at the bottom plane has higher robustness to the variation of various operating parameters with consistently high ZnO fractional conversion. Copyright © 2013 John Wiley & Sons, Ltd.     

The Effect of Silicon Percentage and Shot Peening Operation on Mechanical Properties of Hadfield Steel Containing 17% Manganese

Protection of Metals and Physical Chemistry of Surfaces - The present study examines the effect of shot peening on the wear behavior of austenitic high- manganese steels in both low and high...     

Bridging cell multiscale modeling of fatigue crack growth in fcc crystals

The previously developed bridging cell method for modeling coupled continuum/atomistic systems at finite temperature is used to model fatigue crack growth in single crystal nickel under two crystal orientations at different temperatures. The method is expanded to implement a temperature‐dependent embedded atom method potential for finite temperature simulations avoiding time‐scale restrictions associated with small timesteps. Results for the fatigue simulation were compared with respect to deformation behavior, stress distribution, and crack length. Results showed very different crack growth mechanisms between the two crystal orientations as well as reduced resistance to crack growth with increased temperature. Copyright © 2015 John Wiley & Sons, Ltd.     

Synergistic effect of salt ions and water-soluble amphiphilic compounds of acidic crude oil on surface and interfacial tension

This study investigated the effect of solubility of amphiphilic compounds of acidic crude oil in water on the surface and interfacial tension (IFT) with NaCl, MgCl₂, CaCl₂, and Na₂SO₄ salts. Accordingly, distilled water, along with the salts mentioned in zero ionic strength up to 2 mol were put in contact with crude oil to become saturated with amphiphilic compounds. The effects of these compounds were investigated on the properties of contact water by pH, total organic carbon (TOC), FTIR (Fourier transform infrared spectroscopy), water-air surface tension (ST), and water-n-decane IFT tests. The results showed that some of the organic components of crude oil, especially acidic and basic compounds, are present or soluble in water, which have a significant effect on reducing the surface and IFT. The IFT reduction of water-n-decane was greater than the water-air ST system. Also, the observations showed that for both NaCl and Na₂SO₄ salt water, with increasing ionic strength of water, there was an optimum salinity within the range of 0.1-0.25 mol/L for both salts with the amount of surface and IFT minimized at this point. In the other two salts, this point was delayed upon elevation of ionic strength and was observed at high salinity. In this case, divalent cations reduce tension rate compared to monovalent cations. Due to solubility of acidic and basic groups in water, pH of salt water illustrates an acidic trend. Results of the FTIR test confirmed solubility of these compounds as well.     

Assessment on the mechanical,structural, and thermal attributes of green graphene-based water soluble polymer electrolyte composites

In the current study, graphene oxide (GO) was prepared using green chemistry with modified Hummer's method without incorporating sodium nitrate (NaNO₃). Solvent casting was employed to fabricate GO-doped poly(ethylene oxide) (PEO), that is, PEO/GO composites with various proportion of Na₂SO₄ and were then subjected to characterization via advanced spectroscopic techniques for different physicochemical aspects to estimate their potential applications as marketable products. XRD analysis explored that fabricated composites are more crystalline than neat PEO. PEO/GO/Na₂SO₄ composite films offered maximum crystallinity. SEM displayed the same trend. TG/DTA thermogram exposed better thermal stability than pristine polymer. FTIR studies confirmed complexation among hybrid's components. Elongation-at-break and Young's modulus displayed an enhancing behavior with an incremental loading of salt and filler. In terms of mechanical performance, composite of PEO with 0.37 wt % GO and 0.08 g salt was found to be an ideal composition during the course of study. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48376.     

中间层成分对GTD-111/IN-718高温合金在瞬时液相连接过程中显微组织和力学性能的影响

研究使用不同的中间层瞬时液相连接两种异种高温合金的适用性.在1100℃、不同时间下瞬时液相连接GTD-111/IN-718体系,研究BNi-2、BNi-3和BNi-9三种类型的中间层对该体系显微组织和力学性能的影响.采用场发射扫描电子显微镜和能量色散光谱技术,研究接头区域的成分变化和显微组织.结果表明,非热凝固区Ni3...     

Modeling of Synergetic Effect of LIX 984N and D2EHPA on Separation of Iron and Zinc Using Artificial Neural Network

Artificial neural network was used to predict the synergetic effect of LIX 984N and D2EHPA on separation of iron from zinc solution. The aim was to predict iron and zinc extraction as a function of pH, temperature, and various organic compositions. Optimum number of hidden layers and nodes in each layer were determined. A multilayer network, with two hidden layers (4:9:5:1) was applied to predict zinc and iron extraction. Effect of pH, temperature, extractant composition, and interaction of them on extraction percent was also investigated using 3D plots. The modeling results showed that there is an excellent agreement between the experimental data and the predicted values.     

Channel Models for Medical Implant Communication

Information regarding the propagation media is typically gathered by conducting physical experiments, measuring and processing the corresponding data to obtain channel characteristics. When this propagation media is human body, for example in case of medical implants, then this approach might not be practical. In this paper, an immersive visualization environment is presented, which is used as a scientific instrument that gives us the ability to observe RF propagation from medical implants inside a human body. This virtual environment allows for more natural interaction between experts with different backgrounds, such as engineering and medical sciences. Here, we show how this platform has been used to determine channel models for medical implant communication systems.     

Identifying the period of a step change in high‐yield processes

Quality control charts have proven to be very effective in detecting out‐of‐control states. When a signal is detected a search begins to identify and eliminate the source(s) of the signal. A critical issue that keeps the mind of the process engineer busy at this point is determining the time when the process first changed. Knowing when the process first changed can assist process engineers to focus efforts effectively on eliminating the source(s) of the signal. The time when a change in the process takes place is referred to as the change point. This paper provides an estimator for a period of time in which a step change in the process non‐conformity proportion in high‐yield processes occurs. In such processes, the number of items until the occurrence of the first non‐conforming item can be modeled by a geometric distribution. The performance of the proposed model is investigated through several numerical examples. The results indicate that the proposed estimator provides a reasonable estimate for the period when the step change occurred at the process non‐conformity level. Copyright © 2009 John Wiley & Sons, Ltd.