Analytic Hierarchy Processes for Spectrum Sharing in 5G New Radio Standard

Wireless Personal Communications - The 5th Generation (5G) systems have the objective of delivering fiber like performance in a wireless environment. It is expected to connect all devices including...     

Optimization of multi-pass turning operations using ant colony system

This paper proposes a new optimization technique based on the ant colony algorithm for solving multi-pass turning optimization problems. The cutting process has roughing and finishing stages. The machining parameters are determined by minimizing the unit production cost, subject to various practical machining constraints. The results indicate that the proposed ant colony framework is effective compared to other techniques carried out by different researchers.     

Experimental investigation of a novel alcohol fumigation in a single-cylinder constant speed diesel engine

Biofuels play an important role as alternate fuel in diesel engines. In this paper, alcohol fumigation on a constant speed single-cylinder diesel engine is experimentally investigated. Fumigation is a method by which volatile fuels are injected into the intake manifold. Previously carburation and injection arrangements have been used for fumigation. In this work, computer control injection using LabVIEW software is attempted for alcohol fumigation and common rail is used to inject at same pressure always. Ethanol and methanol at different rates are used as fumigation fuels. The performance and emission characteristics are studied with and without fumigation. Fumigation increases specific fuel consumption (SFC), carbon monoxide emission and hydrocarbon emission. Fumigation decreases brake thermal efficiency at low load, carbon dioxide and smoke. Fumigation increases SFC at medium and high load conditions. The results show that fumigation replaces diesel up to a certain percentage and reduces both nitrogen oxides and smoke.     

Novel thin‐film reactor for photocatalytic degradation of pesticides in an aqueous solution

A thin‐film reactor was fabricated with immobilised TiO₂ and this reactor was used for photocatalytic mineralisation of common pesticides, 2,4‐dichlorophenoxyacetic acid (DPA) and monocrotophos (MCP), and their commercially formulated products in an aqueous solution. Zeolites HY and Hβ with different physico‐chemical properties were chosen as support material. The supported TiO₂ was used for the degradation and mineralisation studies. TiO₂/zeolite‐supported photocatalyst showed enhanced degradation efficiency compared with bare TiO₂ for both DPA and MCP. Formulated pesticides were mineralised at shorter irradiation times than technical grade pesticides. The results clearly demonstrated that the good adsorption capacity of the support, and the effective light utilisation by TiO₂, improved the photocatalytic activity of supported TiO₂. Reusability studies have also shown the stability of supported photocatalysts. Copyright © 2004 Society of Chemical Industry     

DC electrical conduction in heat-treated poly nickel phthalocyanine

Heat treatment of poly nickel phthalocyanine leads to a charge transfer and hence there is an improvement in conductivity by 5 orders of magnitude. DC electrical conductivity measurements have been carried out in the heat-treated samples in the temperature range 270 K-10 K. Mott’s variable range hopping conduction in one dimension is observed in the temperature range 270K-77K and the conductivity remains constant in the temperature range 77K-10K.     

Studies on the anodic dissolution of copper matte

Anodic polarisation studies on copper matte revealed that a copper matte electrode polariess abruptly in H,SO, solution but not in HCl solution. Anodic dissolution of copper matte was studied at various anodic potentials in 2 N solutions of HCl and H,SO,. It was found that at lower anodic potential (around 0.4 volt vs. saturated calomel electrode) copper dissolves preferentially (at 90% current efficiency) over iron (8–10% C.E.), in both the acid solutions. It was further observed that this preferential dissolution of copper takes place over a longer period (about 6 h) in HCl than in H₂SO₄ solution (about 3 h). Preferential dissolution of copper from copper matte was found to be independent of HCl concentration (0.5 N to 4 N). From the X-ray diffraction analysis of the original copper matte and electrolysed copper matte, it was established that digenite and bornite phases of copper matte dissolved causing preferential dissolution of copper.     

Synthesis and characterization of poly (aniline-co-acrylonitrile) using organic benzoyl peroxide by inverted emulsion method

An inverted emulsion process was adopted to synthesize conducting copolymers of aniline and acrylonitrile using benzoyl peroxide (BPO) as a novel oxidizing agent. The influence of polyacrylonitrile (PAN) ratio on the properties of conducting copolymers is reported. The chemical structures of the copolymers were characterized spectroscopically by UV-Vis, FT-IR, FT-Raman and EPR. The solubility of polyaniline (PAni) and PAni–PAN copolymers in dimethyl sulphoxide (DMSO) was confirmed by electronic absorption spectra. The conductivity of these copolymers lie in the range (1.26–4.20)×10⁻² S/cm. TGA thermogram of copolymers showed multi-step thermal degradation behaviour. X-ray scattering studies reflected that the copolymers are semicrystalline and showed two crystalline peaks at 17 and 25 (2θ).     

Performance evaluation of polyaniline pigmented epoxy coating for corrosion protection of steel in concrete environment

Corrosion protection of mild steel reinforcement offered by a newly developed epoxy based coating system containing inherently conducting polyaniline as one of the pigments has been studied. The synthesis of polyaniline and preparation of epoxy based coating system containing this polyaniline are described here. The corrosion resistant property of epoxy polyaniline system, coated on mild steel was evaluated by various techniques such as electrochemical impedance spectroscopy, potential time studies, cathodic disbondment test, anodic polarization study, salt spray test and chemical resistance test. The corrosion resistance of epoxy polyaniline coating system coated on reinforcement bars embedded in concrete was also studied by an accelerated time to cracking study. The formation of polyaniline was characterized using FTIR, UV, GPC, particle size analyzer and fineness studies. Electrochemical impedance studies reveal that the resistance of the coating decreased initially and then increased due to passivating ability of the polyaniline pigment. Based on the results of different techniques, it is found that epoxy coating with polyaniline pigment is effective in corrosion protection of steel in concrete environment.     

Development and testing of nano particulate lubricant for worm gear application

Bio-degradable lubricants are an attractive alternative for the mineral based and synthetic based lubricants. Bio-degradable lubricants are environmental-friendly and non-toxic. The present study deals with the tribological investigation of bio-degradable nano lubricants for worm gear applications. Nano additives like CuO and TiO₂ were used. Bio-degradable oils like palm oil and sunflower oil were used as base oils. The nano lubricants were prepared by adding two nano additives and two bio-degradable oils each of 0.1 % and 0.2 % weight composition. Friction and wear characteristics were tested on pin-on-disc tribometer under varying load conditions. Extreme pressure tests for nano lubricants were carried out using four ball tester. The wear surface obtained was analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy. From the tests conducted, it was found that the addition of nano additives in biodegradable oils reduced the friction co-efficient and wear rate to a considerable extent.

     

Particle swarm optimization (PSO) algorithm for optimal machining allocation of clutch assembly

Nowadays tolerance optimization is increasingly becoming an important tool for manufacturing and mechanical design. This seemingly, arbitrary task of assigning dimension tolerance can have a large effect on the cost and performance of manufactured products. With the increase in competition in today’s market place, small savings in cost or small increase in performance may determine the success of a product. In practical applications, tolerances are most often assigned as informal compromises between functional quality and manufacturing cost. Frequently the compromise is obtained interactively by trial and error. A more scientific approach is often desirable for better performance. In this paper particle swarm optimization (PSO) is used for the optimal machining tolerance allocation of over running clutch assembly to obtain the global optimal solution. The objective is to obtain optimum tolerances of the individual components for the minimum cost of manufacturing. The result obtained by PSO is compared with the geometric programming (GP) and genetic algorithm (GA) and the performance of the result are analyzed .