Optimization of axial compressor stage using NSGA-II technique

G. Chaitanya, J. Suresh Kumar and K Srinivas

Efficiency and Stage Weight [Inlet stage specific Area] are two important design issues which demand specific attention in the design of aero space compressors. In this paper these two objectives were optimized using elitist multi objective genetic algorithm, otherwise known as NSGA-II (Non dominated sorted Genetic Algorithm-II) which was developed by Kalyan Moy Deb [2002]. Lingen Chen and Fengrui Sun (2005) implemented optimum design of a subsonic axial flow compressor stage using mean line prediction method and taking 12 design variables and three objective functions. In the present approach two objective functions were formulated taking 5 design variables into account. The results showing optimal front for the two objectives problem is presented and the sensitivity analysis results of influencing design variables are shown. 

Simple shear behaviour of palm biodiesel contaminated soil

Chew S. J. and C. Y. Lee

Palm biodiesel contaminations may bring adverse effect on basic geotechnical properties of foundation soils. This paper presents the results of an experimental study on shear behaviour of palm biodiesel contaminated sandy soil. A comprehensive set of laboratory experiments have been undertaken in a direct simple shear device on samples of palm biodiesel contaminated sandy soil. In the experiments the soil samples were prepared by mixing the sandy soil with B20 palm biodiesel ranging from 0% to 20% by weight. Stress-strain and shear strength response for the samples were monitored continuously during the experiments. The effect of the palm biodiesel content, relative density and normal stress on the shear behaviour of the sandy soil is investigated and discussed.

Development of a palm nut and fibre separator

Ologunagba F. O., Olutayo L. A. and Ale M. O.

A palm nut and fibre separator was designed, fabricated and tested. The basic features of the seperator are feeding chute, pulverizing unit, separating unit, discharge outlets and the prime mover. The machine was tested at three different machine angle of tilt (10⁰, 20⁰ and 30⁰), two different levels of moisture content termed (dry and wet) and three levels of fibre discharge openings (5, 10 and 15mm). Test results showed that the machine gave its best work performance with dry mixture at 10mm fibre discharge opening and 20⁰ machine angle of tilt. The throughput capacity, separating efficiency and quality performance efficiency were 201.4kg/hr, 96.3% and 81.2%, respectively. The cost of producing one unit of the palm nut and fibre separator as at the time of fabrication was estimated to be N20,460 (twenty thousand four hundred and sixty Naira) not including the cost of electric motor and the power required for operating the machine.

Development of a productivity measurement model for tea industry

R. Gupta and S. K. Dey

India is the largest tea producing country in the world and tea contributes 1% of the GDP of the country, apart from providing a direct livelihood to a large number of workers. However, in the recent past the productivity performance of Indian tea industry has not been very satisfactory. India’s predominance in the tea production is on decline and this has already started showing its bad effect on all the stakeholders. The tea industry in India must search for a comprehensive productivity improvement strategy to overcome the challenge of high competition from other emerging tea producing countries like Srilanka, Kenya, China, Bangladesh and Indonesia in the global level. As a pre-requisite, the quest for a productivity improvement programme follows productivity measurement. But, meticulous literature survey reveals that no study has been undertaken so far on the productivity measurement of a tea industry. Also, the productivity measurement methods presented in the literature are usually too intricate and difficult to apply. The competency and expertise needed for their implementation is scarce in context of Indian tea industry. With this backdrop this paper attempts to propose a relatively simple productivity measurement model suited to tea industry. For this, productivity accounting model is used and suitably given the form so as to fit to a tea industry. A case study, conducted in a tea industry in Assam, India, to analyze the performance of the model is presented. The study reveals that the model is comprehensive and satisfies the six criteria of measurement theory such as validity, comparability, completeness, timeliness, inclusiveness and cost-effectiveness. Further, the study reveals that the proposed model identifies the areas of poor resource utilization responsible for measured total productivity decline in the tea industry. These resources are labour, material and energy and a number of suggestions have been put forward as a mitigating measure.

Investigation on thermal, mechanical and morphological properties of epoxy/UHWPE blends

Shahryar Pashaei, Siddaramaiah and Akheel Ahmed Syed

Abstract:

Epoxy/ultrahigh molecular weight polyethylene (UHMWPE) blends have been prepared by in-situ polymerization method. The effects of UHMWPE from 2.5 wt % to 10 wt % on the tensile properties of blends have been studied. Tensile properties of blends are characterized and were shown that content 10% UHMWPE was effected on performance of polymer blends significantly. Thermal characteristics of the polymer blends were determined by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). TGA thermogram indicated that increased thermal stability of blends after incorporation of UHMWPE. The DSC was shown that T_g of polymer blends increased. The enthalpy of melting (rH_m) obtained from DSC curves was increased with increase in UHMWPE content in epoxy matrix, due to depend on UHMWPE content in blend systems. The rheology of polymer was envisaged by DMA is affected on the polymer blend. The incorporation of UHMWPE increased mechanical properties of blends. Degradation kinetic parameters have been calculated for thermal degradation processes using two mathematical models namely, Coats-Redfern and Broido’s methods. Morphological behaviour of fractured blends has been studied using scanning electron microscopy (SEM).

A novel method of evaluating low curve for SS304 from low cost indentation experiments

A. Kumaraswamy, B. Sridhar Babu and V. Vasudeva Rao

Abstract:

Static indentation and compression tests have been conducted at a common strain rate of 10^-3s^-1 on SS304 heated to 1273 K held there for 30 min and subsequently cooled in the atmosphere. In the present work an attempt was made in evaluating the Constraint Factor (CF) i.e., the ratio of Meyer Hardness to flow stress as a function of average strain perusing the Meyer hardness data points and flow stress data points at constant strain over a considerable strain range. An attempt was also made in converting Meyer hardness Vs average strain curve to a flow curve in uniaxial tensile/compression test by applying CF obtained from the literature. It has been observed that, Meyer hardness Vs average strain curve is matching with flow curve at a CF value of 3.06 for SS304. In addition to this, an effort is made in evaluating the important properties like strain hardening exponent and strength coefficient for SS304 from static indentation and compression tests.

Optical properties modification of poly (vinyl chloride) using complexes of 2-amino acetate benzothiazole

Ahmed Ahmed, Tariq Najim, Jumat Salimon, Nadia Salih, Abdualbasit Graisa, Yang Farina and Emad Yousif

The optical properties of PVC in the region from (200-600 nm) were studied by preparing the composites with 2-amino acetate benzothiazole complexes. The optical data analyzed and interpreted in term of the theory of phonon assisted direct electronic transition; it is observed that the energy is affected by doping type of inorganic complexes used.

Effect of convex die angle of porthole die on elastic deformation and extrusion process in tube extrusion

Rajamamundi Prabhu and V. S. K. Venkatachalapathy

Abstract:

Port hole die extrusion has a great advantage in the forming of hollow section tubes that are difficult to produce by conventional extrusion with a mandrel on the stem. Because of the complicated structure of the die assembly, the extrusion of hollow section tubes has been investigated experimentally. During the hot extrusion of aluminum alloy 6061, the change of process parameters will affect the mechanical properties of extruded products. In this study, Taguchi method is applied to optimize the process parameters in hot extrusion of Al 6061 tubes under extrusion ratio of 24.03. The experiments are arranged by orthogonal array method in which Die with three channels and four channels are used as outer arrays, the factors selected as inner arrays are the billet heating temperature, the convex die angle, bearing length and the container temperature. The extrusions are subsequently tested for tensile test, flattening test, expanding test using a conical punch, surface finish and micro-structure. Test results are analyzed by the quality measurement of Taguchi method to find the relationship between the design process parameters and mechanical properties of the products and to acquire the optimal combination of parameter. Then based on the results obtained from the additive model, conformity experiments are performed.

Renovation with confirmation test for vertical Francis turbine

B. Prabhakar, H. Chandra, A. Tripathi and M. Agrawal

Abstract:

This paper presents confirmation test and renovation of 4x9 MW vertical Francis turbine of UMIAM hydro Power station situated at Shillong, Meghalaya State of India. For this purpose before renovation of plant, test conducted for measurement of various signatures like pressure, temperature, speed, vibration etc. which increase due to old age. The results show that after confirmation test and renovation the generator output is always improved for the parameters like guide vane servomotor stroke, vibration, shaft run out and noise at turbine pit entrance. The result also provides information that the overall efficiency of the plant is increased after renovation.

Molecular interaction studies of glycylglycine in aqueous sodium halide solutions at 303, 308 and 313k

R. Palani, S. Balakrishnan and K. A. Sudhamani

Abstract:

Ultrasonic velocity, density and viscosity have been measured for glycylglycine in aqueous sodium halide (NaF, NaCl, NaBr) mixture (0.5m) at 303, 308 and 313K. Using the experimental values, the adiabatic compressibility, hydration number, apparent molal compressibility, apparent molal volume, limiting apparent molal compressibility, limiting apparent molal volume and their constants (S_K, S_V), transfer volumes at infinite dilution and viscosity B-coefficient of Jones-Dole equation were calculated. These parameters have been interpreted the molecular interactions in terms of solute-co-solute and solute-solvent interaction present in the given solutions.

On yield line estimates of the punching strength of full panel unbonded post-tensioned flat slabs at internal columns

Shodolapo Oluyemi Franklin

Abstract:

In this study, the yield line method of analysis is used to calculate the ultimate punching capacity of ten full panel, unbonded post-tensioned slabs, six of which were subject to combined vertical and transfer of moment loading.  It is found that the method estimates to within 10% the failure loads for cases involving purely vertical loading. However the predictions for those slabs subjected to moment transfer are not consistent. An important consideration in this regards was the presence or otherwise of ordinary bonded reinforcement at the critical positive moment regions of the slabs. It is suggested that alternative flexural mechanisms of punching failure should be utilized in lieu of yield line theory to obtain reliable estimates of the punching capacity.

Simulation and effect of operating variables on the overall thermal efficiency of combined cycle power plant

Bijendra Singh, K. P. Tyagi and Kishor Patil

Abstract:

Combined cycle power plant of gas turbine topping cycle and steam turbine bottoming cycle, are widely used due to their high efficiencies. Combined cycle cogeneration has the possibility to produce power and process steam more efficiently, leading to higher efficiency and reduction in green house emission. The objective of present work, is to simulate and analyze a natural gas fired combined cycle cogeneration unit and to investigate the effect of operating variables on the overall efficiency. The operating variables include compressor inlet temperature, gas turbine inlet temperature, exhaust temperature of gas, inlet temperature of steam and pinch point.

Investigation on thermal, mechanical and morphological behaviours of organo nanoclay incorporated epoxy nanocomposites

Shahryar Pashaei, Siddaramaiah and Akheel Ahmed Syed

Abstract:

A series of epoxy nanocomposites have been prepared with varying compositions viz., 0, 1, 3, and 5 wt % organically modified montmorillonite (MMT) clay. The effects of MMT nanoclay content on the physico-mechanical and thermal properties of epoxy nanocomposites have been studied. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) have been employed to investigate the thermal characteristics and their mode of thermal degradation. The TGA thermograms of nanocomposites exhibits higher decomposition temperature behaviours compared to the pristine epoxy. It was found that the thermal degradation of all epoxy nanocomposites takes place in one step. All the nanocompsoites were stable upto 221 °C. The thermal degradation kinetic parameters of the composites have been calculated using two mathematical models namely, Coats-Redfern and Broido’s methods. The rheology of polymer was envisaged by DMA is affected on the polymer nanocomposite. Morphological behavioours of epoxy/o-MMT nanocomposites assessed by scanning electron microscopy (SEM) method.

Influence of magnetic field and heat transfer on peristaltic flow of Jeffrey fluid through a porous medium in an asymmetric channel

C. Vasudev, U. Rajeswara Rao, M. V. Subba Reddy and G. Prabhakara Rao

Abstract:

In this paper, we studied the effects of heat transfer and magnetic field on the peristaltic flow of a Jeffrey fluid through a porous medium in an asymmetric channel under the assumptions of long wavelength and low Reynolds number. Expressions for the velocity and pressure gradient are obtained analytically. The effects of Hartmann number, Darcy number, phase shift, Jeffrey fluid parameter and upper and lower wave amplitudes on the pumping characteristics and the temperature field are discussed through graphs in detail.