Fabrication and modelling of the macro-mechanical properties of cross-ply laminated fibre-reinforced polymer composites using artificial neural network

The mechanical behaviour of fibre-reinforced polymer composites (FRPCs) is considered very complex due to many factors such as composition, material type, manufacturing process and end user applications. This article presents the mechanical properties and artificial neural network (ANN) modelling results of cross-ply laminated FRPCs. Twenty composite samples were fabricated by varying the number of layers of carbon fibre and glass fibre as reinforcement and polyphenylene sulphide and high-density polyethylene as matrix. Mechanical properties were measured in terms of flexural modulus, hardness, impact and transverse rupture strength. Multilayer feed-forward backpropagation ANN approach was used to predict the mechanical properties by using material type, composition and number of reinforcement and matrix layers as input variables. From 20 data patterns, 16 were used for network training and remaining 4 were used to test the models. Furthermore, trend analysis was also performed to understand the influence of inputs on developed models. It is evident from the ANN prediction results that there is good correlation between predicted and actual values within acceptable mean absolute error. The outcomes of this research will help to reduce cost and time by eliminating tedious composite property measurements and to fabricate tailored composites meeting application requirements.     

Ni(ll) biosorption by Rhizopus arrhizus Env 3: the study of important parameters in biomass biosorption

BACKGROUND: The removal of toxic metals from wastewaters by biosorption, based on the metal‐binding capacities of various biological materials, has attracted much interest. However, the success of this approach depends on economic feasibility, which can be obtained by optimisation of the environmental conditions. In this study, Ni(II) biosorption experiments were carried out using a preformed biomass of Rhizopus arrhizus. A pure culture of previously isolated R. arrhizus Env 3 was used for maximum biosorption of nickel metal from nickel‐electroplating industrial effluent. RESULTS: Various environmental factors such as nickel concentration, pH, temperature, mycelial pellet weight, pretreatment of fungal biomass, dead and living fungal biomass and time course of biosorption by R. arrhizus Env 3 were optimised for maximum removal of nickel from the effluent. The maximum nickel removal rate of 618.5 mg g^?1 was observed with living biomass at pH 8, temperature 35 °C, nickel concentration 500 mg L^?1, pellet size 3 g wet weight and shaker velocity 150 rpm. Maximum nickel biosorption was obtained after 72 h. CONCLUSION: Statistical analysis of different factors such as temperature, pH, mycelial pellet size, concentration of nickel in effluent and residual nickel level showed that all these factors had significant effects on the biosorption of nickel metal by R. arrhizus Env 3 from nickel‐electroplating industrial effluent. Copyright © 2008 Society of Chemical Industry     

Management of natural gas resources and search for alternative renewable energy resources: A case study of Pakistan

Energy usage in Pakistan has increased rapidly in past few years due to increase in economic growth. Inadequate and inconsistent supply of energy has created pressure on the industrial and commercial sectors of Pakistan and has also affected environment. Demand has already exceeded supply and load shedding has become common phenomenon. Due to excessive consumption of energy resources it would become difficult to meet future energy demands. This necessitates proper management of existing and exploration of new energy resources. Energy resource management is highly dependent on the supply and demand pattern. This paper highlights the future demands, production and supply of energy produced from natural gas based on economic and environmental constraints in Pakistan with special emphasis on management of natural gas. An attempt has been made by proposing a suitable course of action to meet the rising gas demand. A mechanism has been proposed to evaluate Pakistan's future gas demand through quantitative analysis of base, worst and best/chosen option. CO₂ emission for all cases has also been evaluated. The potential, constraints and possible solutions to develop alternative renewable energy resources in the country have also been discussed. This work will be fruitful for the decision makers responsible for energy planning of the country. This work is not only helpful for Pakistan but is equally important to other developing countries to manage their energy resources.     

等离子渗镀CrON复合涂层结构与抗铝液熔蚀性能

采用等离子渗氮/电弧离子镀复合方法在H13模具钢表面制备出CrON涂层,研究氧流量对CrON复合涂层结构及抗铝液熔蚀性能的影响。结果表明,随着氧流量的增加,所制备的涂层主要物相由氮化物向氧化物转变,在氧流量较低时主要呈现面心立方CrN结构,而在氧流量为200 mL/min时制备的涂层形成典型的Cr₂O₃晶体相特征。掺入适量的氧,CrN涂层柱状晶生长受到抑制,涂层结构更加致密。涂层表面缺陷和粗糙度随着氧含量的增加而增大。CrON复合涂层在铝液中的失效形式是局部点蚀。由于形成致密的结构和良好的热稳定性,在氧流量为50 mL/min时制备的涂层具有优异的抗铝液熔蚀能力,而氧流量较高时表面生成致密的Cr₂O₃抗氧化层也有利于提高抗铝液熔蚀性能。     

Oesophageal perforation: a dangerous but potentially curable condition

A series of three cases of oesophageal perforation are described. All three presented differently and the X-ray findings were different in the three patients.     

Peristaltically induced flow of nanomaterial through uniform porous space and gravitational aspects

Magneto peristaltic flows of nanofluids play a key role in magnetic drug transport systems. Therefore, peristalsis of a nanofluid through a uniform porous medium under the influence of a uniform magnetic force is studied here. Ohmic heating and Hall aspects are incorporated in the analysis. Three distinct types of nanoparticles (ie, silver, alumina, and copper) have been used for theoretical analysis. A large wavelength and a small Reynolds number scheme are adopted in mathematical modeling. The dimensionless nonlinear system is solved using the well‐known perturbation method, and physical analysis is done via graphs. A comparison of different nanoparticles is also presented. It is noticed that an increase in the Hall effects nullifies the variations, which are due to an increment in the Hartman number. The temperature of the nanofluid can be reduced by increasing the permeability of the porous medium.     

Structural and magnetic studies of Ce-Zn doped M-type SrFe12O19 hexagonal ferrite synthesized by sol-gel auto-combustion method

In the present work, the M-type Sr-hexagonal ferrites having chemical composition Sr_1-xCe_xFe_12-yZn_yO₁₉ (x?=?0.000, 0.025, 0.050, 0.075, 0.10, y?=?0.00, 0.25, 0.50, 0.75, 1.0) are prepared via sol-gel autocombustion technique. The Structural and magnetic properties of M-type Sr-hexagonal ferrites are studied and discussed thoroughly. The structural, micro graphical and magnetic particularities of the samples are calculated through X-Ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) respectively. X-ray diffraction assured that all the synthesized composites possess a pure M-type hexaferrite structure and basic crystalline configuration of Sr-hexaferrite which does not alter by Ce-Zn substitution. It is observed that the Ce-Zn substitution has significant effect on its magnetic properties. VSM results reveal that pure sample has coercivity of 4.49?kOe, which shows the hard nature of the samples. It is perceived that values of remanence (M_r) and saturation magnetization (M_s) decline with increasing the Ce-Zn ions substitution. The reason behind the reduction in magnetic saturation (M_s) and remanence (M_r) might be spin canting and dilution phenomena with increasing the rare earth substituted ions. The large coercivity magnets may be valuable for permanent (stable) magnet applications. The prepared composites could be useful for applications in microwave absorbing materials.     

Synthesis and application of biocompatible nontoxic nanoparticles for reclamation of Ce3+ from synthetic wastewater: Toxicity assessment,kinetic, isotherm and thermodynamic study

The aim of present study is to synthesize forsterite nanoparticles(FRST) for the reclamation of cerium ions(Ce~(3+)) from synthetic wastewater.The aim to synthesize FRST nanoparticles is due to its biocompatible and nontoxic nature.The formation of nanoparticles with average diameter of 58 nm was confirmed by TEM analysis.SEM images of bare FRST nanoparticles show a heterogeneous surface with porous nature.BET surface area of FRST nanoparticles is calculated to be 33.69 m~2/g.The significant uptake of Ce~(3+) ions can be obtained for all the selected concentrations(25-150 mg/L) within 2 h of adsorbent—adsorbate interaction.The pH study shows that by increasing pH from acidic to alkaline range,higher removal can be achieved.Temperature study demonstrates the endothermic nature of Ce~(3+)adsorption.The value of sticking probability suggests very high sticking probability of Ce~(3+) ion for FRST nanoparticles.Ce~(3+) uptake is favored by higher temperature and with the increase in temperature from298 to 328 K,Langmuir adsorption capacity increases from 36.45 to 42.99 m~2/g.Applicability of FRST nanoparticles was also investigated for other light and heavy rare earth elements in single solute and multisolute systems,FRST nanoparticles show the significant removal of divalent metallic pollutants as well.The assessment of chemical toxicity of treated wastewater was carried out with the bioluminescent photobacterium(Vibrio fischeri) and decreased toxicity was observed in treated water samples.The outcome of present study suggests that the FRST nanoparticles can be efficiently utilized for the removal of Ce~(3+) ions and a wide range of other pollutant species as well.     

不同双层结构AlCrN/AlCrVN多层涂层的力学和磨损性能

采用电弧离子镀的方法制备了不同数目（1、2、4、6）双层结构的AlCrN/AlCrVN多层涂层,并研究了多层结构对涂层微观结构、力学、摩擦学和切削性能的影响。结果显示,沉积态AlCrN/AlCrVN多层涂层主要由固溶(Al,Cr)N组成,优先生长方向为[111]晶向。与其他多层涂层相比,具有6层双层结构的AlCrN/AlCrVN涂层在高温下表现出较低的摩擦系数（约0.46）和磨损率（0.15×10^-11 m³/N·m）,以及较高的硬度（HK_0.05=38 000 MPa）和膜-基结合强度（L_C2=53±1 N）。多层涂层相邻层之间形成了较多的界面,有助于提高多层涂层的硬度和耐磨性。切削试验结果显示,当切削磨损标准VB=0.2时,AlCrN/AlCrVN-6涂层具有较高的硬度和耐磨性,最长的切削长度为7.4 m。     

Membranes for CO2 /CH4 and CO2/N2 Gas Separation

Membrane technology has emerged as a leading tool worldwide for effective CO₂ separation because of its well-known advantages, including high surface area, compact design, ease of maintenance, environmentally friendly nature, and cost-effectiveness. Polymeric and inorganic membranes are generally utilized for the separation of gas mixtures. The mixed-matrix membrane (MMM) utilizes the advantages of both polymeric and inorganic membranes to surpass the trade-off limits. The high permeability and selectivity of MMMs by incorporating different types of fillers exhibit the best performance for CO₂ separation from natural gas and other flue gases. The recent progress made in the field of MMMs having different types of fillers is emphasized. Specifically, CO₂/CH₄ and CO₂/N₂ separation from various types of MMMs are comprehensively reviewed that are closely relevant to natural gas purification and compositional flue gas treatment