Density functional study of adsorption and desorption dynamics of hydrogen in zirconium doped aluminium clusters

To reduce the greenhouse effect and as a fuel alternatives hydrogen is used as a secure and clean energy. But there are some challenges in the storage of hydrogen energy, the present accurate dynamics of adsorption and release of hydrogen. We report the adsorption and desorption of hydrogen atoms (up to eight) on the ZrAl_m (m = 3 to 7) clusters using density functional theory within B3PW91/LANL2DZ basis sets in the GAUSSIAN 09 package. Adsorption energy for per hydrogen atom in all clusters is found in the range of ?2.5 eV to ?3.3 eV, which shows the chemisorption of hydrogen on the ZrAl_m clusters. Change in the DOS with number of hydrogen is attributed to the charge transfer between the ZrAl_m clusters and hydrogen atoms. Highest HOMO-LUMO gap of 3.055 eV is found for the ZrAl₃H₇ cluster which indicates that the ZrAl₃H₇ cluster is chemically more stable. Work function values for hydrogen doped clusters are in the range of 3.5 eV–4.4 eV which suggests the low optical absorption in considered clusters. The calculated enthalpy difference further confirms the chemisorption of hydrogen on ZrAl_m clusters ZrAl₃H_n and ZrAl₇H_n(for n = 1 to 5 and 7) are more exothermic than other considered clusters. Desorption energies per hydrogen for these clusters are found lower than the some of the best catalytic clusters Pd₁₃ and Pt₁₃ indicating more catalytic active nature.     

TCP Variants for Mobile Adhoc Networks: Challenges and Solutions

Wireless Personal Communications - Transmission Control Protocol (TCP) provides connection oriented and reliable transport layer services. Mobile Adhoc Networks (MANETs) are autonomous and...     

An efficient oxidative coupling of naphthols catalyzed by Fe impregnated pillared montmorillonite K10

Montmorillonite K10 was modified with pillaring solutions of Fe. The catalyst was activated at different temperatures. The resultant heterogeneous catalyst was used for coupling of 2-naphthol and derivatives under mild operating conditions. The activity of catalyst was compared with Fe pillared bentonite, Fe-exchanged montmorillonite K10 and bentonite catalysts. Amongst them, K10-FePLS120 showed better activity and selectivity. The catalyst can be recycled without loss of activity.     

A fuzzy framework for coordinating pricing and inventory policies for deteriorating items under retailer partial trade credit financing

In this paper, we proposed a generalized economic order quantity (EOQ) – based inventory model using a trade credit policy in a fuzzy sense. The trade credit policy adopted here is a two-level trade credit policy in which the supplier offers the retailer a permissible delay period M, and the retailer, in turn, partially provides customers a permissible delay period N. This study considers fuzzy EOQ model to allow for: (1) selling price dependent demand rate which is imprecise in nature, (2) a profit maximization objective and (3) an imprecise holding cost, ordering cost, purchasing cost, interest earned and interest charged rate. Besides, the cases N ? M and N ? M are explored thoroughly. The objective function for the retailer in fuzzy sense is defuzzified using Modified Graded Mean Integration Representation Method. For the defuzzified objective function sufficient conditions for the existence and uniqueness of the optimal solution are provided. An efficient algorithm is designed to determine the optimal pricing and inventory policies for the retailer. Finally, numerical examples are presented to illustrate the proposed model and the effect of key parameters on optimal solution is examined.     

Coagulation process for tannery industry effluent treatment using Moringa oleifera seeds protein: Kinetic study,pH effect on floc characteristics and design of a thickener unit

The kinetics of coagulation process for turbidity removal from tannery industry effluent using NaCl solution extracted Moringa oleifera protein is reported here. The effect of initial pH of effluent on floc size and strength was analysed. Floc size decrease with increase in velocity gradient and hierarchy of floc size exponent at different pH was: acidic > neutral > basic. It was observed based on the half-life period data that the process follows a second-order kinetic model with 0.000862 (L/mg min) as the rate constant. The Talmadge–Fitch method is used to analyse batch sedimentation data for the calculation of area for the clarifier-thickener unit to treat 5 m³/h of tannery wastewater.     

Joint pricing and replenishment policies for non-instantaneous deteriorating items with imprecise deterioration free time and credibility constraint

This study develops an inventory model for non-instantaneous deteriorating items with imprecise deterioration free time and credibility constraint. The model assumes price sensitive demand when the product has no deterioration and price and time dependent demand when the product has deterioration. Under these considerations, the study attempts to offer best policy for selling price and replenishment cycle for the retailer that aims at maximizing the total profit per unit time. Making use of nearest interval approximation and interval arithmetic, the single objective problem is transformed to multi objective problem. Employing Weighted Sum Method, an analytical approach along with simple algorithm is developed to identify Pareto optimal solution. Finally, the behavior of the model with varied parameters is illustrated in numerical examples.     

Preparation of porous zirconia microspheres by internal gelation method

A modified internal gelation process for the preparation of porous zirconia microspheres has been developed. The conventional method has been modified by adding a surfactant in the feed broth. The effects of variation of surfactant concentration, washing techniques and temperature of calcination on the pore volume and the surface area of the microspheres have been studied. The conditions were optimized to obtain porous stable microspheres suitable for various applications. The microspheres were characterized by surface area analysis, pore volume analysis, thermogravimetric analysis and X-ray diffraction. The ion exchange behavior was studied using pH titration.     

Esophageal actinomycosis in a patient with end‐stage renal disease

Actinomycosis of esophagus is uncommon. Herpes simplex virus, cytomegalovirus, candidiasis, tuberculosis, and other fungal infections are the commonly reported infections in both immunocompromised and immunocompetent patients. We report a case of esophageal actinomycosis in an end‐stage renal disease patient. A 28‐year‐old lady, known case of systemic lupus erythematosus, hepatitis B virus infection with end‐stage renal disease on regular maintenance hemodialysis since 5 years presented with history of epigastric pain and odynophagia for 1 week. Her upper gastrointestinal endoscopic examination revealed extensive necrotic areas with membrane in the esophagus. Histopathology revealed actinomycotic colonies and bacterial clumps. She was treated with intravenous penicillin followed by oral ampicillin for 6 months. She showed marked clinical improvement, and repeat endoscopy showed healing of ulceration and no evidence of actinomycosis.     

Investigation of emulsion and effect on emission in CI engine by using diesel and bio-diesel fuel: A review

The exhaust of diesel engine is a main significant air pollution source which affects the environment and human life. A number of researchers have contributed their valuable efforts from each and every perspective to reduce air pollution. In the present work in-depth analysis is done on the recent investigation which is carried out in the field of alternative Fuels. The study examines the result of several aspects of emulsion stability and also investigated variables such as type of surfactant, mixing speed, mixing time and various additives and its effect on emission. Higher mixing speed with less water percentage increases emulsion stability. The objective of this paper is to highlight the analysis on W/D emulsion fuel, emulsion fuel stability and effect of W/D fuel on combustion, performance and emission characteristic. The results disclose an enhancement in engine performance and reduction of harmful emission for various additives compared to diesel.