Influence of graphite and copper in mechanical properties of aluminum silicon alloy

The present work deals with the mechanical behaviour of the Al-Si-Cu/graphite composite at different strain rates. Stir casting technique was used to fabricate the Al-Si alloy and composite. In order to improve the wettability of graphite with the alloy, graphite particulates were ball milled with Copper and preheated to 400°C. The uniaxial tensile tests were conducted at various strain rates in the range of 10^?4s^?1 to 10^?2s^?1. The ultimate tensile strength of the composite was higher than that of the alloy for all strain rates. The hardness of the composite was also better than that of alloy. The elongation of the alloy was more than that of composite for all strain rates. The uniform distribution of graphite and silicon particles were observed from the microstructure. The fracture mode of alloy and composite were analyzed.     

Male Phyllotreta striolata (F.) Produce an Aggregation Pheromone: Identification of Male-specific compounds and Interaction with Host Plant Volatiles

The chrysomelid beetle Phyllotreta striolata is an important pest of Brassicaceae in Southeast Asia and North America. Here, we identified the aggregation pheromone of a population of P. striolata from Taiwan, and host plant volatiles that interact with the pheromone. Volatiles emitted by feeding male P. striolata attracted males and females in the field. Headspace volatile analyses revealed that six sesquiterpenes were emitted specifically by feeding males. Only one of these, however, elicited an electrophysiological response from antennae of both sexes. A number of host plant volatiles, e.g., 1-hexanol, (Z)-3-hexen-1-ol, and the glucosinolate hydrolysis products allyl isothiocyanate (AITC), 3-butenyl isothiocyanate, and 4-pentenyl isothiocyanate also elicited clear responses from the antenna. The active male-specific compound was identified as (+)-(6R,7S)-himachala-9,11-diene by chiral stationary phase gas-chromatography with coupled mass spectrometry, and by comparison with reference samples from Abies nordmanniana, which is known to produce the corresponding enantiomer. The pheromone compound was synthesized starting from (-)-α-himachalene isolated from Cedrus atlantica. Under field conditions, the activity of the synthetic pheromone required concomitant presence of the host plant volatile allyl isothiocyanate. However, both synthetic (+)-(6R,7S)-himachala-9,11-diene alone and in combination with AITC were attractive in a two-choice laboratory assay devoid of other natural olfactory stimuli. We hypothesize that P. striolata adults respond to the pheromone only if specific host volatiles are present. In the same laboratory set up, more beetles were attracted by feeding males than by the synthetic stimuli. Thus, further research will be necessary to reveal the components of a more complex blend of host or male-produced semiochemicals that might enhance trap attractiveness in the field.     

Physicochemical Studies of 4-Substituted N-(2-Mercaptophenyl)-Salicylideneimines: Corrosion Inhibition of Mild Steel in an Acid Medium

A series of 4-substituted N-(2-mercaptophenyl)salicylideneimine Schiff bases were synthesized and investigated for corrosion inhibition of mild steel in hydrochloric acid medium. Inhibition through adsorption mechanism is proposed for these inhibitors, which is well supported by electrochemical impedance spectroscopy, the Langmuir adsorption isotherm and Scanning Electron Microscope morphologies of inhibited and uninhibited mild steel specimens. The negative ?G _ads indicates the spontaneous adsorption of the inhibitor on a mild steel surface. Among all the examined inhibitors, 5-bromo-N-(2-mercaptophenyl)salicylideneimine showed a higher inhibition efficiency. In order to reveal the usefulness of these Schiff bases as corrosion inhibitors under various circumstances, weight loss measurements were performed at various temperatures, acid concentrations and immersion times.     

Economic order quantity for deteriorating items with time discounting

In this paper, an economic order quantity model for deteriorating items with time discounting has been developed for varying demand pattern over a fixed planning horizon. Optimal solutions with complete backlogging and without backlogging are established and has proven that the total variable cost is convex. The main contribution of this paper is based on the assumption of the demand which is the linear function of the instantaneous stock level I(t). In this paper, a new type of demand has been considered which will help us to obtain qualitative insights without much analytical complexity. Optimal solutions of the proposed models are derived and effects of deterioration on the inventory replenishment policies are studied with the help of numerical examples.     

Soil burial,tensile properties,morphology, and biodegradability of (rice husk powder)‐filled natural rubber latex foam

The focus of this research work was to study the possibilities of enhancing the biodegradation process of natural rubber latex foam (NRLF) by incorporating rice husk powder (RHP). Different loadings of RHP (2.5, 5.0, 7.5, and 10 phr) were used in this study. Controlled and RHP‐incorporated NRLF samples were subjected to natural soil environment for 90 days. Properties of unexposed and those exposed to soil burial condition samples were compared and studied. Tensile properties, such as tensile strength and elongation at break, dropped significantly with increasing RHP loading on natural soil exposure for 90 days. Exposed RHP‐incorporated NRLF weight loss also showed increased biodegradability with increasing RHP loading. The changes in morphological properties were evident by tabletop microscopy (TM1000). J. VINYL ADDIT. TECHNOL., 21:128–133, 2015. © 2014 Society of Plastics Engineers     

A Hybrid Interior Rotor High-performance Line Start Permanent Magnet Synchronous Motor

Abstract—This article describes the development of a line start permanent magnet synchronous motor with a rotor containing interior mounted magnets. The rotor is a hybrid of both circumferentially as well as radially magnetized magnets arranged so it produces consequent poles. Steady-state and transient performances of the line start permanent magnet synchronous motors have been analyzed by using time-stepping finite-element analysis. Simulation results show that the optimum performance of the rotor is achieved for a specific magnet volume, a substantial improvement on performances of all such rotors reported so far (based on the detailed study of all these rotor types). The hybrid rotor has improved the synchronous performance of the machine without degrading its starting characteristics when compared with an equivalent induction motor. Two experimental prototypes of the proposed design have been built in the laboratory, and their performances have been compared with the performance of a conventional line start permanent magnet synchronous motor having only circumferentially magnetized magnets in its rotor, as well as that of a standard induction motor of the same frame size and physical dimensions. The results indicate that the proposed hybrid interior rotor significantly improves machine performance.     

Interface Oxygen Vacancy-Enhanced Co3O4/WO3 Nanorod Heterojunction for Sub-ppm Level Detection of NOx

Herein, a cobalt oxide/tungsten oxide (Co₃O₄/WO₃) p–n heterojunction for NO_x detection is developed and optimized. Field-emission scanning electron microscopy shows that the WO₃ nanorods are embellished with Co₃O₄ nanostructure. X-ray photoelectron spectroscopy reveals the presence of oxygen vacancy on the Co₃O₄ coupled with WO₃ heterojunction. Compared to bare WO₃ and pure Co₃O₄, the Co₃O₄/WO₃ heterojunction sensor shows significant sensitivity to NO_x at 200 °C. The sensor exhibits higher linearity from 0.4 to 10 ppm of NO_x, with a sensing response of 4.4–93%. The NO_x sensitivity of the Co₃O₄/WO₃ heterojunction sensor is ninefold higher than that of the pure WO₃ sensor. Even in a high humidity (84%) environment, the Co₃O₄/WO₃ heterojunction sensor demonstrates high NO_x sensitivity. The sensor maintains remarkable stability measured for up to 4 weeks. The possible NO_x sensing mechanism of the Co₃O₄/WO₃ heterojunction is additionally discussed.     

Performance Enhancement and Comparison of Graphene Field Effect Transistor Devices Coated with HMDS Layer

Silicon - Graphene-based devices show good transfer characteristics, which depend upon the surface morphology of the material and substrate. During fabrication of the device, the substrate...     

Developing Outstanding Bifunctional Electrocatalysts for Rechargeable Zn-Air Batteries Using High-Purity Spinel-Type ZnCo2Se4 Nanoparticles

Zinc-air batteries are gaining popularity as viable energy sources for green energy storage technologies. The cost and performance of Zn-air batteries are mostly determined by the air electrodes in combination with an oxygen electrocatalyst. This research aims at the particular innovations and challenges relating to air electrodes and related materials. Here, a nanocomposite of ZnCo₂Se₄@rGO that exhibits excellent electrocatalytic activity for the oxygen reduction reaction, ORR (E_1/2 = 0.802 V), and oxygen evolution reaction, OER (η₁₀ = 298 mV@10 mA cm⁻²) is synthesized. In addition, a rechargeable zinc-air battery with ZnCo₂Se₄@rGO as the cathode showed a high open circuit voltage (OCV) of 1.38 V, a peak power density of 210.4 mW cm⁻², and outstanding long-term cycling stability. The electronic structure and oxygen reduction/evolution reaction mechanism of the catalysts ZnCo₂Se₄ and Co₃Se₄ are further investigated using density functional theory calculations. Finally, a perspective for designing, preparing, and assembling air electrodes is suggested for the future developments of high-performance Zn-air batteries.