Machinability of bronze-alumina composite with tungsten carbide cutting tool insert

Bronze-alumina metal matrix composites have been attracting the interest of researchers in recent years, as they have many advantageous characteristics. The mechanical properties of the bronze-alumina composite are improved by the addition of alumina in the matrix. In this present work, bronze was reinforced with 10 wt% alumina particles. The bronze-alumina composite was prepared by stir-casting method. Preheated alumina particles were introduced into the vortex of the molten alloy created by a rotating impeller. Machining studies were conducted on bronze and bronze-alumina composite using tungsten carbide cutting tool insert. The flank wear of the carbide tools on machining bronze-alumina composite is higher than on machining bronze because of the abrasive characteristics of alumina. The cutting force during machining of bronze is lower when compared to that on machining bronze-alumina composite. The bronze exhibited slightly better surface finish than bronze-alumina composite

Preparation of nanofiber particles from the leaf of Aristida hystrix and its characterization

Natural fibers have been focused by researches to develop high performance and eco-friendly reinforcement in polymer composites. The present work is deliberated on the characterization of nanoparticles of Aristida hystrix (AH) leaf fiber to confirm their compatibility as reinforcement in polymer composites. The macro leaf fiber is reduced to nanofiber particles by ball milling method. From the characterization results, the AH leaf nanoparticles had cellulose content of (61.21 wt %) and crystallinity index (58.37%). The thermal stability of AH nanofiber particles was studied under nitrogen and oxygen environment. From the results obtained, the thermal stability of this fiber was found to be closer to 298.6°C and 312.6°C respectively. The morphological analysis evidenced that the cellulosic particles were in nanoscale. The antibacterial activity of AH nanofiber particles against Escherichia coli, Acetino bacteria, Klebsiella pneumonia, and Staphylococcus aureus was determined by well diffusion method. The extracted AH nanopowder prepared by distilled water showed the maximum zone of inhibition against all tested bacterias in low concentrations (50 mg/50 µL). The zone of inhibition of AH fiber particles was better in Staphylococcus aureus bacteria, which is suitable for the medical applications

EFFECT OF GASOLINE - ETHANOL BLENDS ON PERFORMANCE AND EMISSION CHARACTERISTICS OF A SINGLE CYLINDER AIR COOLED MOTOR BIKE SI ENGINE

This paper investigates the effect of using gasoline-ethanol (GE) blends on performance and exhaust emission of a four stroke 150 cc single cylinder air cooled spark ignition (SI) engine, without any modifications. Experiments were conducted at part load and different engine speeds ranging from 3000 to 5000 rpm, without and with catalytic converter. Ethanol content was varied from 5 percentage to 20 percentage by volume and four different blends (E5, E10, E15 and E20) were tested. Fuel consumption, engine speed, air fuel ratio, exhaust gas temperature and exhaust emissions were measured during each experiment. Brake thermal efficiency (ηb,th), volumetric efficiency (ηvol), brake specific fuel consumption (BSFC) and excess air factor were calculated for each test run. Brake specific fuel consumption, volumetric efficiency and excess air factor increased with ethanol percentage in the blend. Carbon monoxide (CO), hydrocarbon (HC) and oxides of nitrogen (NOx) emissions decreased with blends

Evaluation of drilled hole quality of Al-Si alloy/fly ash composites produced by powder metallurgical technique

414-420<span style="font-size:9.0pt;mso-bidi-font-size:10.0pt;mso-bidi-language: TA" lang="EN-US">Metal matrix composites have high strength to weight ratio, high toughness, high impact strength, low sensitivity to temperature changes and high surface durability. In the present study, aluminium silicon alloy - fly ash composites are developed using powder metallurgy technique. Aluminium silicon alloy powder is homogenously mixed with fly ash and uniaxially compacted<span style="font-size:9.0pt;mso-bidi-font-size:10.0pt;mso-bidi-font-weight: bold;mso-bidi-font-style:italic" lang="EN-US">. The green compacts are sintered at the temperature of 600ºC. The <span style="font-size:9.0pt; mso-bidi-font-size:10.0pt" lang="EN-US">micro structural characterization<span style="font-size:9.0pt;mso-bidi-font-size:10.0pt;mso-bidi-language: TA" lang="EN-US">, hardness and <span style="font-size:9.0pt;mso-bidi-font-size: 10.0pt" lang="EN-US">drilled hole quality <span style="font-size:9.0pt; mso-bidi-font-size:10.0pt;mso-bidi-language:TA" lang="EN-US">in terms of surface roughness, diameter error and roundness error were studied on Al-Si alloy and Al-Si alloy - fly ash composites. Microstructure proved that the fly ash particles are located in grain boundary after sintering. The hardness of Al-Si alloy - fly ash composites is higher than that of Al-Si alloy due to grain refinement. The surface roughness of Al-Si alloy - fly ash composites increased with increasing speed, feed and fly ash content. The <span style="font-size: 9.0pt;mso-bidi-font-size:10.0pt;mso-bidi-language:TA" lang="EN-US">diameter error of Al-Si alloy and Al-Si alloy - fly ash composites is higher than that of roundness error. </span

Physicochemical properties of new cellulosic fiber extracted from Carica papaya bark

This article presents the characteristics of Carica papaya fibers (CPFs) extracted from the bark of the perennial papaya plant. Detailed chemical compositions of CPFs such as cellulose, lignin, ash, moisture, and wax contents were established and determined by using standard methods. Further, chemical groups, crystalline structure, surface roughness, and thermal stability of CPFs were examined using Fourier transform infrared analysis, X-ray diffraction, atomic force microscope, and thermogravimetric analysis, respectively. The physico-chemical properties of CPFs, crystallinity index (56.34%), cellulose content (38.71 wt. %), hemicellulose (11.8%), and density (943 kg/m3) were compared to those properties of other natural fibers. The results suggest that the biodegradable CPFs can be used as a potential reinforcemnet in the polymer matrix composite structure

Multi-response optimisation of sintering parameters of Al-Si alloy/fly ash composite using Taguchi method and grey relational analysis

In this paper, an attempt has been made to optimise the sintering process parameters of Al-Si (12%) alloy/fly ash composite using grey relational analysis. Al-Si alloy/fly ash composite was produced using powder metallurgy technique. Al-Si alloy powder was homogenously mixed with various weight percentages of fly ash (5-15 wt.%) and compacted at a pressure ranging from 307 to 512 MPa. The green compacts were sintered at temperatures between 575 and 625°C. Experiments have been performed under different conditions of temperature, fly ash content, and compacting pressure. Taguchi&#039;s L9 orthogonal array was used to investigate the sintering process parameters. Optimal levels of parameters were identified using grey relational analysis, and significant parameter was determined by analysis of variance. Experimental results indicate that multi-response characteristics such as density and hardness can be improved effectively through grey relational analysis