Venkateswara Babu P., Ismail Syed and Satish Ben Beera
In an internal combustion engine, piston ring-cylinder liner tribo pair is one among the most critical rubbing pairs. Most of the energy produced by an internal combustion engine…
Abstract
Purpose
In an internal combustion engine, piston ring-cylinder liner tribo pair is one among the most critical rubbing pairs. Most of the energy produced by an internal combustion engine is dissipated as frictional losses of which major portion is contributed by the piston ring-cylinder liner tribo pair. Hence, proper design of tribological parameters of piston ring-cylinder liner pair is essential and can effectively reduce the friction and wear, thereby improving the tribological performance of the engine. This paper aims to use surface texturing, an effective and feasible method, to improve the tribological performance of piston ring-cylinder liner tribo pair.
Design/methodology/approach
In this paper, influence of positive texturing (protruding) on friction reduction and wear resistance of piston ring surfaces was studied. The square-shaped positive textures were fabricated on piston ring surface by chemical etching method, and the experiments were conducted with textured piston ring surfaces against un-textured cylinder liner surface on pin-on-disc apparatus by continuous supply of lubricant at the inlet of contact zone. The parameters varied in this study are area density and normal load at a constant sliding speed. A comparison was made between the tribological properties of textured and un-textured piston ring surfaces.
Findings
From the experimental results, the tribological performance of the textured piston ring-cylinder liner tribo pair was significantly improved over a un-textured tribo pair. A maximum friction reduction of 67.6 per cent and wear resistance of 81.6 per cent were observed with textured ring surfaces as compared to un-textured ring surfaces.
Originality/value
This experimental study is helpful for better understanding of the potency of positive texturing on friction reduction and wear resistance of piston ring-cylinder liner tribo pair under lubricated sliding conditions.
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Meiling Wang, Qin Li, Zhiqiang Huang, Weiji Qian, Xiong Chen, Qiang Li and Tianhua Lai
This study aims to solve the premature failure of the rubber stator due to wear, reduce the frictional resistance moment of the screw pump to solve the problem of a model of…
Abstract
Purpose
This study aims to solve the premature failure of the rubber stator due to wear, reduce the frictional resistance moment of the screw pump to solve the problem of a model of Daqing oilfield screw pump oil recovery system shutdown after the difficult start.
Design/methodology/approach
For the first time, the rotor surface of a screw pump was treated with dot-matrix texture to study the effect of dot matrix texture on the tribological performance of the stator-rotor friction subsets of screw pump. Reciprocating friction tests with different texture morphologies (S-shape, double tongue) and angular parameters (0°, 45° and 90°) were conducted at 10% of the texture area and pump silicone grease.
Findings
When point texture was added to the surface of the rotor sample, the friction coefficient and wear quantity of the sample were lower than those of the surface without texture treatment, and the double tongue 0° combination showed the best tribological properties. At this time, the average coefficient of friction and wear is reduced by 22.8% and 62%, 28.6% and 64.8%.
Originality/value
The introduction of texture can effectively improve the tribological performance of progressive screw pumps, and this paper provides important theoretical and experimental support for the design of progressive screw pumps in practical applications.
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Chaduvula Vijaya Lakshmi, Ch. Ravi Kiran, M. Gowrisankar, Shaik Babu and D. Ramachandran
The paper aims to throw light on the interactions taking place between the different chemical compositions at various temperatures. P-methylacetophenone is a polar dissolvable…
Abstract
Purpose
The paper aims to throw light on the interactions taking place between the different chemical compositions at various temperatures. P-methylacetophenone is a polar dissolvable, which is positively related by dipole–dipole co-operations and is exceptionally compelling a direct result of the shortfall of any critical primary impacts because of the absence of hydrogen bonds; hence, it might work an enormous dipole moment (μ = 3.62 D). Alcohols additionally assume a significant part in industries and research facilities as reagents and pull in incredible consideration as helpful solvents in the green innovation. They are utilized as pressure-driven liquids in drugs, beauty care products, aromas, paints removers, flavors, dye stuffs and as a germ-free specialist.
Design/methodology/approach
Mixtures were prepared by mass in airtight ground stopper bottles. The mass measurements were performed on a digital electronic balance (Mettler Toledo AB135, Switzerland) with an uncertainty of ±0.0001 g. The uncertainty in mole fraction was thus estimated to be less than ±0.0001. The densities of pure liquids and their mixtures were determined using a density meter (DDH-2911, Rudolph Research Analytical). The instrument was calibrated frequently using deionized doubly distilled water and dry air. The estimated uncertainty associated with density measurements is ±0.0003 g.cm−3. Viscosities of the pure liquids and their mixtures were determined by using Ostwald’s viscometer. The viscometer was calibrated at each required temperature using doubly distilled water. The viscometer was cleaned, dried and is filled with the sample liquid in a bulb having capacity of 10 ml. The viscometer was then kept in a transparent walled water bath with a thermal stability of ±0.01K for about 20 min to obtain thermal equilibrium. An electronic digital stop watch with an uncertainty of ±0.01 s was used for the flow time measurements for each sample at least four readings were taken and then the average of these was taken.
Findings
Negative values of excess molar volume, excess isentropic compressibility and positive values of deviation in viscosity including excess Gibbs energy of activation of viscous flow at different temperatures (303.15, 308.15 and 313.15 K) may be attribution to the specific intermolecular interactions through the hetero-association interaction between the components of the mixtures, resulting in the formation of associated complexes through hydrogen bond interactions.
Originality/value
The excess molar volume (VE) values were analyzed with the Prigogine–Flory–Patterson theory, which demonstrated that the free volume contribution is the one of the factors influencing negative values of excess molar quantities. The Jouyban–Acree model was used to correlate the experimental values of density, speed of sound and viscosity.
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K. Suneetha, S.M. Ibrahim and G.V. Ramana Reddy
The purpose of this paper is to investigate the steady 2D buoyancy effects on MHD flow over a permeable stretching sheet through porous medium in the presence of suction/injection.
Abstract
Purpose
The purpose of this paper is to investigate the steady 2D buoyancy effects on MHD flow over a permeable stretching sheet through porous medium in the presence of suction/injection.
Design/methodology/approach
Similarity transformations are employed to transform the governing partial differential equations into ordinary differential equations. The transformed equations are then solved numerically by a shooting technique.
Findings
The working fluid is examined for several sundry parameters graphically and in tabular form. It is observed that with an increase in magnetic field and permeability of porous parameter, velocity profile decreases while temperature and concentration enhances. Stretching sheet parameter reduces velocity, temperature and concentration, whereas it increases skin friction factor, Nusselt number and Sherwood number.
Originality/value
Till now no numerical studies are reported on the effects of heat source and thermal radiation on MHD flow over a permeable stretching sheet embedded in porous medium in the presence of chemical reaction.
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K. Suneetha, S.M. Ibrahim and G.V. Ramana Reddy
The purpose of this paper is to address the combined effects of thermal radiation and chemical reaction on steady MHD mixed convective heat and mass transfer flow past a vertical…
Abstract
Purpose
The purpose of this paper is to address the combined effects of thermal radiation and chemical reaction on steady MHD mixed convective heat and mass transfer flow past a vertical surface under the influence of Joule and viscous dissipation.
Design/methodology/approach
The governing system of partial differential equations is transformed to dimensionless equations using dimensionless variables. The dimensionless equations are then solved analytically using perturbation technique.
Findings
With the help of graphs, the effects of the various important parameters entering into the problem on the dimensionless velocity, dimensionless temperature and dimensionless concentration fields within the boundary layer are discussed. The authors noticed that the velocity increases with an increase in the porosity parameter. An increase in the Prandtl number Pr, decreases the velocity and the temperature field. An increase in the radiation parameter, decreases the velocity and the temperature field. Also the effects of the pertinent parameters on the skin-friction coefficient and rates of heat and mass transfer in terms of the Nusselt and Sherwood numbers are presented numerically in tabular form.
Originality/value
To the best of the authors’ knowledge, recent this work has not been finished by any other researchers.
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M.C. Raju, S.V.K. Varma and A.J. Chamkha
The purpose of this paper is to present an analytical study for a problem of unsteady free convection boundary layer flow past a periodically accelerated vertical plate with…
Abstract
Purpose
The purpose of this paper is to present an analytical study for a problem of unsteady free convection boundary layer flow past a periodically accelerated vertical plate with Newtonian heating (NH).
Design/methodology/approach
The equations governing the flow are studied in the closed form by using the Laplace transform technique. The effects of various physical parameters are studied through graphs and the expressions for skin friction, Nusselt number and Sherwood number are also derived and discussed numerically.
Findings
It is observed that velocity, concentration and skin friction decrease with the increasing values of Sc whereas temperature distribution decreases in the increase in Pr in the presence of NH.
Research limitations/implications
This study is limited to a Newtonian fluid. This can be extended for non-Newtonian fluids.
Practical implications
Heat and mass transfer frequently occurs in chemically processed industries, distribution of temperature and moisture over agricultural fields, dispersion of fog and environment pollution and polymer production.
Social implications
Free convection flow of coupled heat and mass transfer occurs due to the temperature and concentration differences in the fluid as a result of driving forces. For example, in atmospheric flows, thermal convection resulting from heating of the earth by sunlight is affected differences in water vapor concentration.
Originality/value
The authors have studied heat and mass transfer effects on unsteady free convection boundary layer flow past a periodically accelerated vertical surface with NH, where the heat transfer rate from the bounding surface with a finite heat capacity is proportional to the local surface temperature, and which is usually termed as conjugate convective flow. The equations governing the flow are studied in the closed form by using the Laplace transform technique. The effects of various physical parameters are studied through graphs and the expression for skin friction also derived and discussed.
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Ramakrishna Guttula and Venkateswara Rao Nandanavanam
Microstrip patch antenna is generally used for several communication purposes particularly in the military and civilian applications. Even though several techniques have been made…
Abstract
Purpose
Microstrip patch antenna is generally used for several communication purposes particularly in the military and civilian applications. Even though several techniques have been made numerous achievements in several fields, some systems require additional improvements to meet few challenges. Yet, they require application-specific improvement for optimally designing microstrip patch antenna. The paper aims to discuss these issues.
Design/methodology/approach
This paper intends to adopt an advanced meta-heuristic search algorithm called as grey wolf optimization (GWO), which is said to be inspired by the hunting behaviour of grey wolves, for the design of patch antenna parameters. The searching for the optimal design of the antenna is paced up using the opposition-based solution search. Moreover, the proposed model derives a nonlinear objective model to aid the design of the solution space of antenna parameters. After executing the simulation model, this paper compares the performance of the proposed GWO-based microstrip patch antenna with several conventional models.
Findings
The gain of the proposed model is 27.05 per cent better than WOAD, 2.07 per cent better than AAD, 15.80 per cent better than GAD, 17.49 per cent better than PSAD and 3.77 per cent better than GWAD model. Thus, it has proved that the proposed antenna model has attained high gain, leads to cause superior performance.
Originality/value
This paper presents a technique for designing the microstrip patch antenna, using the proposed GWO algorithm. This is the first work utilizes GWO-based optimization for microstrip patch antenna.
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P. Gangadhara Rao and B. Ramesh Babu
The need for continuing professional education (CPE) for librariansis discussed. The libraries and educational institutions in Tamil Naduare briefly examined and attempts at CPE…
Abstract
The need for continuing professional education (CPE) for librarians is discussed. The libraries and educational institutions in Tamil Nadu are briefly examined and attempts at CPE programmes in India are traced. A draft plan for CPE for librarians in Tamil Nadu is presented and the New Education Policy of the Government of India and role of the UGC and staff colleges are highlighted. Obstacles to CPE are listed.
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Anantha Kumar K., Sugunamma V., Sandeep N. and Ramana Reddy J.V.
The purpose of this paper is to scrutinize the heat and mass transfer attributes of three-dimensional bio convective flow of nanofluid across a slendering surface with slip…
Abstract
Purpose
The purpose of this paper is to scrutinize the heat and mass transfer attributes of three-dimensional bio convective flow of nanofluid across a slendering surface with slip effects. The analysis is carried out subject to irregular heat sink/source, thermophoresis and Brownian motion of nanoparticles.
Design/methodology/approach
At first, proper transmutations are pondered to metamorphose the basic flow equations as ODEs. The solution of these ODEs is procured by the consecutive application of Shooting and Runge-Kutta fourth order numerical procedures.
Findings
The usual flow fields along with density of motile microorganisms for sundry physical parameters are divulged via plots and scrutinized. Further, the authors analyzed the impact of same parameters on skin friction, heat and mass transfer coefficients and presented in tables. It is discovered that the variable heat sink/source parameters play a decisive role in nature of the heat and mass transfer rates. The density of motile microorganisms will improve if we add Al-Cu alloy particles in regular fluids instead of Al particles solely. A change in thermophoresis and Brownian motion parameters dominates heat and mass transfer performance.
Originality/value
To the best of the knowledge, no author made an attempt to investigate the flow of nanofluids over a variable thickness surface with bio-convection, Brownian motion and slip effects.
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B. Ramesh Babu and M. Tamizhchelvan
Describes the results of a research survey conducted at the Department of Library and Information Science, University of Madras, Chennai, India which examines features provided in…
Abstract
Describes the results of a research survey conducted at the Department of Library and Information Science, University of Madras, Chennai, India which examines features provided in online public access catalogues (OPACs) in Tamil Nadu. OPACs are recent developments in libraries in India in general and Tamil Nadu in particular. A review of the literature reveals that only a few studies on OPACs in India have been conducted and there is no comprehensive study about the OPACs in Tamil Nadu. A sample of 50 libraries in Tamil Nadu were selected at random, out of which 36 responded. The analysis of the data represents the state‐of‐the‐art of the libraries in the summer of 2002. The major findings of the survey reveal emerging trends in OPAC.