Salalah College of Technology
Salalah, Oman
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Khan S.A.,Salalah College of Technology
Physics Teacher | Year: 2010

Spherometers are instruments designed to measure the radius of curvature of spherical surfaces.1,2 They are particularly useful in situations where only a portion of the spherical surface is available, for example, for measuring the radii of curvature of spherical lenses.3 A spherometer can be easily modified so that it can also be used to measure the radius of curvature of a right circular cylinder. The resulting device is called a cylindrometer (also known as the cylindrospherometer). The idea is quite old4 but is seldom mentioned in introductory laboratory courses. This paper describes the device and its operation.

Abdul Gaffar S.,Salalah College of Technology | Ramachandra Prasad V.,Madanapalle Institute of Technology and Science | Vijaya B.,Jawaharlal Nehru University
Journal of the Brazilian Society of Mechanical Sciences and Engineering | Year: 2017

In this article, the nonlinear, steady-state boundary layer flow and heat transfer of an incompressible Eyring–Powell non-Newtonian fluid from a vertical porous plate is investigated. The transformed conservation equations are solved numerically subject to physically appropriate boundary conditions using a second-order versatile, implicit finite-difference Keller Box technique. The numerical code is validated with previous studies. The influence of a number of emerging non-dimensional parameters, namely Eyring–Powell rheological fluid parameters (ε), the local non-Newtonian parameter based on length scale x (δ), Prandtl number (Pr), Biot number (γ) and dimensionless tangential coordinate (ξ) on velocity and temperature evolution in the boundary layer regime are examined in detail. Furthermore, the effects of these parameters on surface heat transfer rate and local skin friction are also investigated. It is found that the velocity is reduced with increasing ε but temperature is increased. Increasing δ enhances velocity but reduces temperature. The increasing γ is observed to enhance both velocity and temperature. And an increasing Prandtl number Pr is found to decrease both velocity and temperature. © 2017, The Brazilian Society of Mechanical Sciences and Engineering.

Ramamoorthy R.,Schlumberger | Venkatesan T.,Salalah College of Technology | Rajendran R.,B.S. Abdur Rahman University
SAE Technical Papers | Year: 2017

Machining of materials has received significant consideration due to the increasing use of machining processes in various industrial applications. In machining, the heat generated in the cutting zone during machining is critical in deciding the work piece quality. Lubricants are widely used to reduce the heat generation. Their usage poses threat to environment and health hazards. Hence, there is a need to identify eco-friendly and user-friendly alternatives to conventional cutting fluids. Modern tribology has facilitated the use of solid lubricants such as graphite, calcium fluoride, molybdenum disulphide, and boric acid as an alternative to cutting fluids in machining. Solid lubricant assisted machining is an environmental friendly clean technology for improving the surface quality of the machined work piece. The present work investigates the role of solid lubricant assisted machining with graphite lubricants on surface quality while machining EN 8 steel.The performance of solid lubricant assisted machining has been studied in comparison with that of wet machining. The results indicate that there is a considerable improvement in the process performance with solid lubricant assisted machining as compared to that of machining with cutting fluids. Results show considerable improvement in the surface finish with the use of solid lubricants. Due to the presence of solid lubricants, there is a decrease of surface roughness as compared to dry hard turning. © Copyright (c) 2017 SAE International and Copyright (c) 2017 SAE INDIA.

Prasad V.R.,Madanapalle Institute of Technology and Science | Gaffar S.A.,Salalah College of Technology | Beg O.A.,Gort Engovation Research
Journal of Thermophysics and Heat Transfer | Year: 2015

Buoyancy-driven laminar free-convection flow, heat, and mass of a non-Newtonian nanofluid from a horizontal circular cylinder to a micropolar fluid have been investigated numerically using an implicit finite difference scheme. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. A nonsimilarity solution is presented that depends on the Prandtl number Pr, Schmidt number Sc, Brownian motion parameter Nb, thermophoresis parameter Nt, material parameter K, and buoyancy ratio parameter N. It is observed that increasing the Brownian motion parameter increases the temperature, Sherwood number, and wall couple stress but decreases the velocity, concentration, angular velocity, skin friction, and Nusselt number. An increase in the thermophoresis parameter is observed to accelerate the velocity, concentration, angular velocity, skin friction, and Nusselt number, whereas it decreases the temperature, the reduced Sherwood number, and wall couple stress. The velocity, angular velocity, Nusselt number, and wall couple stress are reduced with increasing material parameters, whereas the temperature, concentration, skin friction, and Sherwood number are enhanced. It is also observed that increasing material parameters increases velocity, angular velocity, skin friction, Nusselt number, and Sherwood number but decreases temperature, concentration, and wall couple stress. The model finds applications in energy systems and the thermal enhancement of industrial flow processes. Copyright © 2014 by the American Institute of Aeronautics and Astronautics, Inc.

Palit S.,Judges Bagan | Palit S.,Salalah College of Technology
International Journal of ChemTech Research | Year: 2012

The vision of environmental engineering is wide, varied and unparalled. The changing world has prompted scientists to target towards green chemistry and green engineering. Green engineering encompasses environmental engineering. The path of success is visionary. Environmental engineering along with dye degradation techniques is ushering in a new era and new vision environmental pollution control. Conventional and traditional textile wastewater and effluent treatment procedures are a challenge to environmental engineers and environmental scientists because of the restrictions on effluent quality by the environmental pollution control authorities. Dyes cannot be destroyed by primary and secondary treatments. Primary treatment encompasses coagulation and flocculation while secondary treatment involves activated sludge process. Both of these treatments do not successfully degrade textile dyes and the dyes are recalcitrant to these treatments. So the need for tertiary treatment process-advanced oxidation process such as ozonation. Bubble column reactor is an efficient and visionary alternative to the environmental pollution problem. The present aim and objective is to present and project effectively the importance of bubble column reactor and ozonation of dyes as the reaction medium in it. The vision of advanced oxidation process will move towards a newer direction if science and technology surges in this new visionary area.

Alami M.,Salalah College of Technology
International Journal of Applied Linguistics and English Literature | Year: 2016

Given that a systematic treatment of Persian Discourse Markers (hereafter DMs) is almost absent in modern Persian linguistics and to bridge this gap, the audio-recorded data comprising 14 face to face casual conversations involving two-party and multi-party interactions among family members, acquaintances and close friends are used to shed light on these ‘frequently used’ but ‘frequently unnoticed’ linguistic elements. To document a list of the most common DMs typically used in Tehrani dialect of Persian language and to have a detailed description of their discoursal functions in talk, Brinton’s (1996) binary classification of DMs functions (textual and interpersonal) was developed to provide an empirically-supported account of the functions and position of Persian DMs in interaction among Tehrani speakers. The present account of DMs which is basically ‘analytical description’ provides the reader with the knowledge about how Persian DMs operate in actual usage. The findings are built upon a 3105-word corpus including 14 audio-recorded conversations among 50 participants. Altogether 34 tokens of Persian DMs with an overall 254 occurrences were identified among which na/na baba (no/no daddy) with the total of 33 (12.84%) occurrences were the most frequently used Persian DM in the data which are followed by dige (no English equivalent), aare/ba’ale (yep/yes), yani (I mean), vali (but), haalaa/ alaan (now), bebin/nega kon (look) and aslan (by no means/ never).To the author, research on the functions and distributional patterns of Persian DMs will broaden our knowledge of their discoursal behavior in language in general and contribute to the already growing cross-linguistic body of work on DMs. © 2016, Australian International Academic Centre PTY LTD. All rights reserved.

Ahmed Khan S.,Salalah College of Technology
Optik | Year: 2011

In their most recent article, Grado-Caffaro et al. have addressed the question of the 'photon velocity'. They have expressed the photon velocity in terms of the wavefunctions of the Klein-Gordon equation (Grado-Caffaro and Grado-Caffaro [4]). In this note, we closely follow their work and explicitly obtain the photon velocity using the free solutions of the Klein-Gordon equation. It is shown that the plane wave solutions give rise to six possible values of the photon velocity. Two of these solutions are the most expected (v=c). The remaining four solutions, the real pair 0.786c and the imaginary pair 1.272ic are difficult to comprehend. © 2010 Elsevier GmbH © 2010 Published by Elsevier GmbH. All rights reserved.

Khan S.A.,Salalah College of Technology
Optik | Year: 2010

Matrix representations of Maxwell's equations have a striking resemblance to the Dirac equation. We exploit this resemblance to build a beam optics formalism from an exact eight-dimensional matrix representation of the Maxwell equations. The Foldy-Wouthuysen iterative diagonalization technique is employed to obtain a Hamiltonian description for a system with varying refractive index. The beam-optical Hamiltonian is shown to have a wavelength-dependent part, resulting in the wavelength-dependent modifications of light beam optics. The present study is the generalization of the traditional and non-traditional prescription of Helmholtz optics. © 2008 Elsevier GmbH. All rights reserved.

Alami M.,Salalah College of Technology
International Journal of Applied Linguistics and English Literature | Year: 2016

Given the fact that English is the language of the latest technological and scientific developments, comprehending English texts has priority for students to gain the knowledge and skills they will need in the future. However, most Omani students are not efficient L2 readers and do not have sufficient competence in reading authentic English texts. There is a variety of factors that might affect Omani students’ ability to read and comprehend English texts effectively. To find out what factors are involved in Omani students’ reading comprehension, in the first place, it is necessary to know what strategies they employ in reading. To this end, the current study attempts to explore Omani students reported use of reading strategies using ‘Metacognitive Awareness of Reading Strategies Inventory’ (MARSI) developed by Mokhtari and Reichard (2002). The self-reported survey completed by 200 students (90 female and 110 male) who enrolled for Advanced Foundation program (level 4) at Salalah College of Technology (SCT). The results show that SCT students’ awareness of metacognitive strategies is at medium level (3.46). Furthermore, the comparison between two gender groups (Males Vs. Females) shows that male students use metacognitive reading strategies moderately (3.28) while female students use them more frequently (3.64). The outcomes of the study contribute to the improvement of SCT students reading ability and can be used by teachers to teach students different strategies to build meaning of the reading material which is among the goals of any educational system. © 2016, Australian International Academic Centre PTY LTD. All rights reserved.

Khan S.A.,Salalah College of Technology
Optik | Year: 2014

An exact treatment of beam optics, starting ab initio from the Maxwell's equations is presented. The starting point of this approach is a matrix representation of the Maxwell's equation in a medium with varying permittivity and permeability. Formal expressions are obtained for the paraxial and leading order aberrating Hamiltonians, without making any assumptions on the form of the varying refractive index. We derive the wavelength-dependent contributions at each order, starting with the lowest-order paraxial Hamiltonian. To illustrate the general theory, we consider the computations of the transfer maps for an axially symmetric graded-index medium. For this system, in the traditional approaches, one gets only six aberrations. In our formalism, we get all the nine aberrations permitted by the axial symmetry. The six aberrations coefficients of the traditional approaches get modified by the wavelength-dependent contributions and the remaining three are pure wavelength-dependent. It is very interesting to note that apart from the wavelength-dependent modifications of the aberrations, this approach also gives rise to the image rotation. The present study is the generalization of the traditional and non-traditional prescription of Helmholtz optics. In the low wavelength limit our formalism reproduces the Lie algebraic formalism of optics. The present study further strengthens the close analogies between the various prescriptions of light optics and charged-particle optics. The new formalism presented here, provides a natural framework to study beam-optics and polarization in a unified manner. © 2013 Elsevier GmbH.

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