Simultaneous effect of particle size and location on stress development in the electrodes of lithium-ion batteries

In this study, stress generation at the electrode in Li-ion batteries was studied using a two-dimensional cell-scale model that includes multiple active particles during galvanostatic discharge. Numerical simulations were performed using an electrochemical–mechanical coupled model to elucidate the simultaneous effects of particle size and location, lithium intercalation kinetics and binder constraints on the stress. The simulation results showed that when different sizes of particle are considered in the electrode, the small particles were discharged more than the large particles, resulting in higher level of stress in the smaller particles. In addition, the closer the particles were located to the separator, the larger the stresses that were developed in those particles. Therefore, a layered structure, where the particle size gradually increases as the distance from the particles to the separator decreases, can alleviate stress on the electrode. When binder constraints were considered for the electrode particles, the stress was increased at the anode and alleviated at the cathode upon discharge. This indicates that the effect of mechanical constraints on stress generation in the particles differs in the lithiation and delithiation process.     

Telecom sector of Pakistan: Potential,challenges and business opportunities

Pakistan has exercised major developments recently in the Telecom sector. The main focus is to extend maximum benefits to the general user in terms of having accessibility to the modern services and better quality of service as a result of competitive environment amongst the network operators. The international investors also have directly contributed towards the economy as a result of which further horizons for exploring and improving the broadband market have emerged. In this paper, we have presented the growing telecom access and statistics, investment opportunities in the sector, modern applications and the broadband developments in line with the changing orientation of the telecom industry of Pakistan.     

High performance Nylon12/clay nanocomposites for potential packaging applications

The barrier property enhancement of polymers is presently a matter of great concern for the manufacturing of food packaging and films with excellency in moisture and gas resistance. The objective of this work was to enhance the barrier performance of Nylon12/kaolin clay nanocomposites against water vapors and oxygen. Kaolin clays of different aspect ratios were utilized for nanocomposites manufacturing. Nanocomposites were prepared in twin screw extruder operating at 160–200°C, with an increment of 10°C, and at 110 rev/min. The loading of clay was varied from 1 to 5 wt%. Scanning electron microscopy and X-ray diffraction characterizations were used to investigate the morphological properties of nanocomposites. The transmission electron microscopy analysis was used to confirm the dispersion of clays in Nylon12 matrix. Enhancement in barrier performance of nanocomposite was noticed at 5 wt% clay loading. Oxygen barrier of nanocomposites was observed to be more prominent than water vapors owing to the presence of hydrogen bonding in Nylon12 structure which restricted oxygen passage. Experimental barrier values of nanocomposites were also fitted on barrier models namely Nielsen, Cussler model, and Gusev-Lutsi model.     

The application of in situ formed mixed iron oxides in the removal of strontium and actinides from nuclear tank waste

This article discusses the experimental program conducted at Argonne National Laboratory to study the performance of in situ formed mixed iron oxides (IS‐MIO) for the removal of strontium (Sr), plutonium (Pu), neptunium (Np), uranium (U), and americium (Am) from the Savannah River Site (SRS) radioactive tank waste. The boundaries for the experimental work were defined in collaboration with SRS. IS‐MIO was actually found to be a mixture of Fe(II) and Fe(III) oxides and hydroxides, including magnetite. Decontamination factor (DF) values were measured for both IS‐MIO and monosodium titanate (MST), the baseline sorbent used by SRS. DF values for IS‐MIO were found to be superior to MST for all isotopes studied. DF values for Pu, Np, and Sr, achieved within 30 min of IS‐MIO formation were orders of magnitude larger than the needed values. DF values for U and Am were less than the former three but still acceptable, and greater than MST. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

Study of sensitization and different heating cycles on stainless steels used for automotive exhaust components

In order to achieve a reasonable lifetime of automotive exhaust components, a large number of high alloyed ferritic and austenitic stainless steels are used nowadays. It is a common concept that the lifetime of a component is directly related to the performance of steel against corrosion. The components are divided into different sections depending on their service temperatures. High temperature oxidation resistance is one of the properties which are required in different sections. The effect of material sensitization on corrosion resistance of stainless steels is well understood from the literature. Besides, sensitization materials in exhaust systems have to withstand different cyclic heating and cooling phases. The objective of this study was to develop a basic understanding that can determine the influence of different temperature treatments on stainless steels. A fundamental understanding on the interaction of sensitization and cyclic heat impacts are presented in the paper.     

Providing cleaner energy access in Indonesia through the megaproject of kerosene conversion to LPG

In 2007 Indonesia undertook a massive energy program to convert its primary cooking fuel from kerosene to LPG in more than 50 million households. This megaproject, to be completed in late 2011, provided an improved household cooking fuel, with its associated benefits in user costs, cleanliness, convenience, and environment, and reduced the government's huge subsidy for petroleum fuels. Presented from the perspective of Pertamina, Indonesia's sole NOC, and the program implementer, this paper describes the background of the fuels situation, the planning stages, including the preparatory analytical work, targeted market surveys and tests, and the subsequent building of the financial, technical, and institutional models for carrying out the program on an expeditious schedule. It presents the project's major execution steps, results of the program to date, and the unique institutional roles of each party, including the activities and benefits for the government, Pertamina, the public, the industry, and the crucial agents in the fuel supply chains. Finally there is a retrospective policy analysis and a discussion of key factors and challenges in the execution of Indonesia's largest-ever energy initiative to provide improved cooking fuel.     

Homotopy perturbation transform method for nonlinear equations using He’s polynomials

In this paper, a combined form of the Laplace transform method with the homotopy perturbation method is proposed to solve nonlinear equations. This method is called the homotopy perturbation transform method (HPTM). The nonlinear terms can be easily handled by the use of He’s polynomials. The proposed scheme finds the solution without any discretization or restrictive assumptions and avoids the round-off errors. The fact that the proposed technique solves nonlinear problems without using Adomian’s polynomials can be considered as a clear advantage of this algorithm over the decomposition method.     

Multifunctional leather surface embedded with zinc oxide nanoparticles by pulsed laser ablation method

A simple procedure was used to generate and decorate leather structures with different amounts from zinc oxide (ZnO) nanoparticles to produce multifunctional leather structure by pulsed laser ablation method in liquid media based on changing the ablation time in just one-pot method. The impact of varying concentrations of ZnO nanoparticles embedded on the surface of leather on water resistance, water vapor permeability, mechanical characteristics, and UV-shielding efficiency was examined by different characterization techniques like X-ray diffraction, surface area, UV–visible spectroscopy, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. The results showed that the combination between the external functional groups of leather with ZnO nanoparticles was discovered. ZnO nanoparticles effectively coated the surface of leather tissue, as seen by SEM images, and their form a spherical morphology. Leather with ZnO nanoparticles added had the highest capacity to kill Escherichia coli bacteria, exceeding leather without modification and ZnO nanoparticles alone in 50-hr incubation. In addition, the incubation period had a substantial impact on the suppression of Staphylococcus aureus bacteria growth by leather samples.     

Nanocrystalline cellulose reinforced PVDF-HFP membranes for membrane distillation application

Polyvinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) membranes containing different amounts of nanocrystalline cellulose (NCC) were fabricated by electrospining technique for application in membrane distillation (MD). The effect of incorporating NCC on the mechanical strength, morphology, pore size distribution, and liquid entry pressure (water) of the fibrous was investigated. Incorporation of NCC in PVDF-HFP matrix improved the tensile strength and Young's modulus and narrowed down the pore size distribution of the fabricated membranes. Liquid entry pressure, which is an important parameter to ensure high salt rejection of the membranes in MD, was improved from ~ 19 psi to ~ 27 psi with the addition of 2 wt.% NCC. Fabricated membranes were tested in direct contact membrane distillation (DCMD). MD operation data revealed water flux of 10.2–11.5 Lh^− 1 m^− 2 with salt rejection of 99% for these NCC-incorporated membranes.