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Search Results: 1 - 10 of 4385 matches for " Joel; "
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Finite Element Wear Behavior Modeling of Al/Al2SiO5/C Chilled Hybrid Metal Matrix Composites (CHMMCs)  [PDF]
Joel Hemanth
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.27118
Abstract: This paper describes research on aluminum based metal matrix hybrid composites reinforced with kaolinite (Al2SiO5) and carbon (C) particulates cast using high rate heat transfer technique during solidification by employing metallic, non-metallic and cryogenic end chills. The effect of reinforcement and chilling on strength, hardness and wear behavior are discussed in this paper. It is discovered that cryogenic chilled MMCs with Al2SiO5-9 vol.%/C-3 vol.% dispersoid content proved to be the best in enhancing the mechanical and wear properties. A physically based Finite element (FE) model for the abrasive wear of the hybrid composite developed is based on the mechanisms associated with sliding wear of ductile aluminum matrix of the composite containing hard Al2SiO5 and soft carbon (dry lubricant) reinforcement particles. Finally the results reveal that there is a good agreement that exists between the simulated (FE) values and those of the experimental values, proving the suitability of the boundary conditions.
The Impact of ‘Violating the Heterosexual Norm’ on Reading Speed and Accuracy  [PDF]
Joel Dickinson
Psychology (PSYCH) , 2011, DOI: 10.4236/psych.2011.25071
Abstract: This study explores the impact of “schema non-congruent” content on reading speed that has been found in relation to non-stereotypical gender roles. The goal of the present study is to assess if this effect translates to material that violates the “heterosexual norm”. Further, the present study explores whether the impact can be minimized by providing context prior to the exposure of sentences. Data indicated that the impact of sexuality was dependent on the gender of the main character and whether participants had been primed with context or not. Regardless of the time taken to read sentences, accuracy of material was recalled at a constant rate. In conclusion, the activation of “heterosexuality” does seem to be an automatic process such as the activation of gender.
Heat Transfer Analysis during External Chilling of Composite Material Castings through Experimental and Finite Element (FE) Modelling  [PDF]
Joel Hemanth
Modeling and Numerical Simulation of Material Science (MNSMS) , 2014, DOI: 10.4236/mnsms.2014.41001
Abstract:
In controlled solidification, one of the important factors that affects heat transfer from the solidifying casting is the resistance offered at the casting/chill interface. In the present investigation, heat transfer analysis during solidification of Al-12%Si (LM 13) alloy is carried out by collecting temperature history of the solidifying casting. The temperature distribution during solidification in the present investigation is obtained using ANSYS multiphysics software and further for comparison. The temperature profiles are also obtained by FE (Finite Element) modelling using the same software. By using a temperature data logger and lab view based software, the temperature data is acquired and processed at every second. The cooling curves obtained are analysed to know the effect of chilling on solidification behaviour of Al-12%Si alloy castings. Finally, it is concluded from the above research that the cooling curves and temperature distribution obtained by FE analysis do not so closely converge with the experimental data due to modelling limitations.
Effect of Metallic, Nonmetallic, Water Cooled and Cryogenic Chills on Pearlite Content (PC), Eutectic Cell Count (ECC) and Grain Size (GS) of Hypo Eutectic Nickel Alloyed Cast Iron  [PDF]
Joel Hemanth
Modeling and Numerical Simulation of Material Science (MNSMS) , 2017, DOI: 10.4236/mnsms.2017.71001
Abstract: This paper presents the results obtained, deductions made from solidification behaviour and a series of micro structural studies such as pearlite content, eu-tectic cell count and grain size of hypoeutectic gray cast iron which was sand cast (CO2 moulding) using metallic, nonmetallic, water cooled and subzero (cryogenic) end chills. Hypo-eutectic cast irons containing C 3.42, Si 2.4 and Ni 1.5 with impurity contents (S, P, Mn etc.) were solidified unidirectionally in an American Foundrymen Society (AFS) standard mould, the end of which was provided with different end chills to study the effect of chilling during solidifi-cation. The melts were inoculated with 0.3% Fe-Si to promote graphitization. It was observed that the transition from one structure to another is more gradual than normally obtained in the structure of cast irons solidified mul-ti-directionally in a sand mould at room temperature. Austenite dendrite interactions were shown to be a major factor in determining the microstructure, in which the higher dendrite reaction leads to changes in DAS, ECC and GS. It is observed that, the number of eutectic cells is an index of graphite nucleation and the effect of these on structure, since the eutectic cells are developed on the graphite nuclei during solidification.
Scanning Electron Microscopy (SEM) Analysis and Hardness of Diffusion Bonded Titanium-Titanium and Titanium-Copper Plates with Static Force and without Interlayers  [PDF]
Joel Hemanth
Open Journal of Composite Materials (OJCM) , 2017, DOI: 10.4236/ojcm.2017.72007
Abstract: In the present research, commercially pure Ti (grade-2) has been diffusion bonded with Ti and Cu plate under static force without any interlayers. The diffusion bonded samples were tested for micro hardness and micro structural analysis through optical microscopy and SEM. It is found from the present investigation that the bonded zone is affected by the processing variables such as bonding time (1 - 2 h), bonding force (250 N), bonding temperature (973 - 1073 K) and surface roughness. Results of the investigation revealed that temperature range of ?973 - 1073 K along with time duration of 1 - 2 hours in vacuum has resulted in a joint having high hardness with minimum pores. Hardness of the bond depends on the grain boundary diffusion at the interface and maximum hardness was achieved in the case of Ti-Cu joints. When Ti-Cu plates were used for bonding at 973 K for 2 hours, Cu-Ti solid solution along with a zone of different intermetallics was formed in the bonded zone. However, at higher temperatures, no continuous zone of intermetallics was found in the bonded region but instead Ti-Cu solid solution appeared.
Experimental, Mathematical and Finite Element Analysis (FEA) of Temperature Distribution through Rectangular Fin with Circular Perforations  [PDF]
Joel Hemanth
Modeling and Numerical Simulation of Material Science (MNSMS) , 2017, DOI: 10.4236/mnsms.2017.72002
Abstract: Fins are the extended surfaces through which heat transfer takes place to keep the surface cool. Fins of various configurations are presently used ranging from automobile engine cooling to cooling of computer parts. Note that in a fin majority of the heat transfer to atmosphere is by convection and therefore in the present research, and importance is given to variation of temperature along the length of the fin which in turn gives rate of heat transfer. In the present research a solid rectangular aluminum fin and the same rectangular fin with different perforations (2, 4, 8 and 10) were compared analytically, experimentally and its validity through finite element analysis for its temperature distribution along the length. From the present research it is observed that the mathematical and FEA for a solid rectangular fin without perforations are converging within ±1°C and rectangular fin with 10 perforations are converging within ±2°C and hence the validity.
Development of Nickel Alloy Reinforced with Fused SiO2 Chilled Composites and Evaluation of Thermal Properties (Thermal Conductivity & Coefficient of Thermal Expansion) and Temperature Distribution by Finite Element Analysis (FEA)  [PDF]
Joel Hemanth
Open Journal of Composite Materials (OJCM) , 2017, DOI: 10.4236/ojcm.2017.75017
Abstract: This paper presents the results obtained and the discussions made from a series of thermal experiments involving Nickel alloy (ASTM A 494 M) reinforced with fused SiO2, and size of the particles dispersed varies from 80 - 120 μm and amount of addition varies from 3 to 12 wt.% in steps of 3 wt.%. The resulting chilled MMCs are solidified under the influence of copper chill of 25 mm thickness to study the effect of chilling on thermal behaviour. Microstructural studies indicated that the reinforcement distribution is uniform with very good bonding due to chilling effect. Thermal properties were found to decrease significantly with increase in SiO2 content in chilled MMCs. It is concluded from the research that reinforcement content and the temperature has an effect on coefficient of thermal expansion and thermal conductivity of the chilled composite developed. Finite element analysis of the exhaust valve of the IC indicates that chilled Ni alloy composite developed in the present research can be used as alternate material for the existing valve material (Ni-Cr alloy steel). All the tests conducted in this research are in conformance with ASTM standards.
Pupils’ Perceptions of the Teacher’s Changing Role in E-Learning Physics Classroom Instruction  [PDF]
Joel K. Kiboss
Creative Education (CE) , 2010, DOI: 10.4236/ce.2010.11006
Abstract: This article explores the pupils’ view of the teacher’s changing role as a result of the implementation of an innovation that involved electronic learning measurement lessons in a developing country, namely Kenya. 118 randomly pupils enrolled in schools that could be visited conveniently in Nakuru district, Kenya were exposed to an electronic learning program (ELP) in physics. The ELP physics module was developed from a physics course dealing with the concept of measurement. The content was based on the Kenya Institute of Education (KIE) approved syllabus for science education, science textbooks and other relevant materials. Part of the investigation was to determine the effect of the ELP physics module on pupils’ perspectives of the teacher’s role during the physics course. The participants were interviewed at random using the Pupils’ Interview Guide (PIG). A selected group of pupils’ own expressions were also analyzed. The results showed that the conceptions of the pupils who were exposed to the e-learning program and those not so exposed differed remarkably. For, the pupils in the experimental condition depended more on their peers and the program while their counterparts in the traditional class were more dependent on the teacher. The study concludes that the use of ELP module to support conventional physics instruction can have substantial advantages over other approaches.
Influence of E-Learning Environment Program on Pupils’ Instructional Approaches in Physics Measurement Lessons in Kenyan Secondary Schools  [PDF]
Joel K Kiboss
Creative Education (CE) , 2011, DOI: 10.4236/ce.2011.23033
Abstract: This article explores the pupils’ approaches and development of measurement concepts in an innovation that involved an e-learning environment in school physics conducted in a developing country, namely Kenya. A total of 118 randomly pupils enrolled in schools that could be visited conveniently in Nakuru district, Kenya were exposed to an e-learning environment program (ELEP) in physics for a period of six weeks. The ELEP physics module was developed from a physics course dealing with the concept of measurement. It was chosen because the majority of teachers viewed it as a topic that is difficult to teach through the regular method. The content was based on the Kenya Institute of Education (KIE) approved syllabus for science education, science textbooks and other relevant materials. Part of the investigation was to gain insight on the pupils’ approaches and reactions to having to learn measurement concepts through ELEP. In order to achieve this, they were interviewed and other information captured during the physics course to understand what really transpired when they were learning measurement concepts using the ELEP lessonware. The participants’ classroom behaviors were captured using the Physics Practical Lessons Analysis System (PPLAS) and Classroom Practical Work Assessment (CPWA). A selected group of pupils’ were also interviewed to gain insight into their own expressions using the Pupils’ Interview Guide (PIG). The results showed effective approaches and reactions that the pupils exposed to the computer-augmented lessons used to learn physics that differed remarkably from those denied this program. For, the pupils in the experimental condition depended more on their peers and the program while their counterparts in the traditional class were solely dependent on the teacher. The study concludes that the use of ELEP to support conventional physics instruction can have substantial advantages over other instructional methods. Moreover, it proved that the use of ELEP enabled the learners not only to actively participate in the learning process and to engage fully in the instructional process but to under build a deeper understanding of measurement and procedural skills.
The Role of the Pharmacist in Pre-Exposure Prophylaxis  [PDF]
Celia Moffat Joel Matyanga
Pharmacology & Pharmacy (PP) , 2014, DOI: 10.4236/pp.2014.53029
Abstract:

Pre-exposure prophylaxis is a new HIV prevention method that has shown to be effective in HIV uninfected persons at very high risk of HIV infection. It involves daily use of truvada in combination with other proven methods of HIV prevention. The aim of this paper is to discuss the various roles that pharmacists play in pre-exposure prophylaxis to maximize therapy.

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