A study on electrochemical micromachining of super duplex stainless steel for biomedical filters

D. Saravanan, M. Arularasu and K. Ganesan

In recent days, industries are looking for miniature components which can perform complex functions in the areas of electronics, biomedical and nuclear applications. Electrochemical micromachining (ECMM) is an emerging non-conventional technology for producing micro/meso scale components. The micromachining of super duplex stainless steel (SDSS) is generally very difficult, less accurate and time consuming when using many of the non-conventional machining methods. By the use of ECMM the above limitations can be overcome. In this paper, an experimental investigation is carried out to identify the optimal machining parameters for machining SDSS using ECMM. Experiments are conducted based on Taguchi L₁₈ orthogonal array to find the influencing machining parameters on material removal rate (MRR). Statistical analysis of variance is performed to determine the percentage contribution of individual process parameters on MRR. Among the various factors investigated, duty cycle is found to be the most significant factor and contributes about 42% to the MRR. As the duty cycle increases, the pulse on time also increases which contributes to more MRR. The parameters such as current 0.6 amps, voltage 9V, frequency 30 Hz, electrolyte concentration 0.5 mol/lit and duty cycle 66.66% produce maximum MRR in the micromachining of SDSS. This research helps to understand the selection of the machining parameters for ECMM of SDSS.

Energy factor modeling and model reference adaptive control of chaos in CUK converter

R. Manikumar and R. Kayalvizhi

Chaos is an apparently disordered deterministic behavior, which is universally occurring in many systems in all areas of science. In this paper, chaos in CUK converter has been analyzed by taking the input supply voltage as a bifurcation parameter under open loop condition. The mathematical model of the CUK converter is obtained using Energy Factor modeling approach. A Lyapunov’s stability based Model Reference Adaptive controller (MRAC) is designed for the CUK converter and is implemented to control chaos by keeping the system stable from chaotic stage. The proposed adaptive controller, in the on line mode has the ability to track a specific high-frequency reference voltage and also to adapt for the variations in the load and high-frequency pulsed supply voltage. The simulation results show that the proposed method updates the adjustable parameter values to guarantee stable operation from chaotic stage and also to provide good dynamical responses.

Modeling and control of split capacitor type elementary additional series positive output super lift converter

T. S. Saravanan, R. Seyezhai and V. Venkatesh

Super lift converter is a new series of DC/DC converter possessing high voltage transfer gain, high efficiency, reduced ripple voltage and current. Super lift technique armed by split capacitors increases the output voltage in higher geometric progression. This paper focuses on splitting the input side capacitor of the additional series positive output super lift converter in order to obtain a high voltage transfer gain. The proposed super lift converter is modeled using state space averaging technique. A suitable PI controller has been designed to regulate the converter against audio susceptibility and output impedance variation. Simulation study of the proposed converter along with the controller has been carried out in MATLAB/SIMULINK to investigate the static and dynamic response of the converter.

Main geochemical association of the sulfides lead-zinc mineralization in Trepça mineral belt- Artana mine, Kosovo

B. Durmishaj, S. Hyseni, A. Tashko, M. Kelmendi, M. Operta and I. Tahiri

In this paper presented the distribution of average contents of major metals (Pb, Zn, Ag and Au) and accompanying metals in mineral deposit “Përroi i ngjyrosur”. With specific emphasis, we studied the main geochemical association of sulfides mineralization. Based on correlation and factorial analysis, result these geochemical associated as follows: Au-Cu -Pb-As (Zn-Ag-Sb); Ag-Bi-Pb-(Zn-Cu-Cd), and Sb, in antagonism with Cd-As-(Pb-Zn-Au-Ag).

Comparative study of photovoltaic fed DC motor and PMDC motor pumping system

N. Chandrasekaran, B. Ganeshprabu and K. Thyagarajah

Abstract:

Water pumping system has become one of the most feasible photovoltaic (PV) applications. Moreover, PV pumping is getting more attention in recent days mainly in remote areas where connection to the grid is technically not possible. Power generation by Photovoltaic is reliable. The simplest PV water pumping system consists of a PV array connected to boost converter feeding power directly to a DC motor or PMDC motor and a pump. This paper deals with the simulation of PV based DC motor pumping system and PMDC motor pumping system. The comparison of the two systems has been done and proved a simple but efficient photovoltaic water pumping system among them. Motors and centrifugal pumps operate at variable speed in a photovoltaic pumping system. However, the characteristics of motors and pumps are usually only given for a single voltage and speed. To analyze operation of a pumping system, where the solar radiation causing variation in the photovoltaic power, the input/output relationship of the motor-pump assembly and motor characteristics must be determined. The results obtained from the simulation of the system are satisfactory. It is found that PMDC pumping system is better.

Implementation of a time table generator using visual basic.Net

Abstract:

A lecture and examination Timetable Generator (TTGen) for the Department of Electrical and Electronics Engineering, University of Agriculture, Makurdi, Nigeria was designed and implemented using Microsoft’s Visual Basic.Net and MySQL database server as a backend. The application has the ability to manage Students, Lecturers, Venues, Periods, and Courses, of the Department. It also features an image handling module for the lecturer, student and venue objects. The data from the application is saved in a MySQL database using a configurable database module and a Randomizer module to generate the best combination of courses and periods for an efficient time Table. Using the TTGen, Lecture and examination timetables with no infringements for the first semester of the 2009/2010 academic session were generated after only eight iteration steps. The timetable generator is capable of arranging timetable schedules for many departments and faculties of universities and similar institutions where course units are offered.

Planning for refurbishment projects: The effects of organizational complexity and integration on project performance

Ismail Bin Rahmat, Mohamed S. Abd. Elforgani and Hamimah Adnan

This paper measures the influence of the complexity of organizational structure of construction firms and the integrative mechanisms used in the planning process of refurbishment projects. The approach takes the form of a literature review of published journals and textbooks, a postal questionnaire survey with planning engineers and contract managers. Ninety-four construction companies were selected for the postal questionnaire survey. Fifty-four (57%) of returned questionnaires were considered to be useful for statistical analysis. This paper found that all construction firms extensively use integrative mechanisms in the planning process of refurbishment projects. Complex construction firms use integrative mechanisms more extensively than simple construction firms, thus less efficient. However, the project performance of complex construction firms is not significantly better than simple construction firms. The study is limited to medium and large refurbishment projects, with contract value above £500,000 pounds. This paper helps the construction firms to design appropriate organizational structure for refurbishment projects. It also identifies the integrative mechanisms to be used in the planning process of refurbishment projects. It suggests that the organizational structure for construction firms undertaking refurbishment projects should be simple and flexible. This paper determines the types and the extent of use of integrative mechanisms in the planning process of refurbishment projects. It shows how efficiency in the planning process can be affected by the complexity of the organizational structure and the use of integrative mechanisms of the construction firms.

Study of corrosion and synergistic actions of inhibitors on the fatigue properties of mild steel rods

Adebayo A. and Aremu B.

Abstract:

This work, investigates the effects of corrosion and synergistic actions of inhibitors on the fatigue properties of mild steel rods. The corrodents are saltwater and sulphuric acid while the inhibitors used are potassium chromate and 0.5M Zinc oxide. The saltwater is sodium chloride solution containing approximately 3.5% weight of solute, prepared from 97.5% Table salt; this approximates to the average salt concentration in quiet seawater. Mild steel water corroded in 0.5M H₂SO₄ was found to have shorter fatigue life (measured by number of cycles-to-failure) from those corroded in saltwater. Moreover, the fatigue life of specimens soaked in the  corrodent in which both ZnO and K₂Cr₂O₇ (of equal proportion) are added were observed to be longer than the fatigue life of  the sample soaked in the corrodent with only k₂Cr₂O₇. However specimens in the corrodent with only ZnO displayed the least fatigue life. These findings therefore, shows that sulphuric acid has more corrosive action on mild steel than salt water and that the corrosion inhibitor ability of K₂Cr₂O₇ (for mild steel) is more than that of ZnO while the mixture of K₂Cr₂O₇ and ZnO produce best corrosive inhibitor compared to those of the individual inhibitors.

Analysis of steam recuperative system to COGAS plant

E. A. Ogbonnaya and H. U. Ugwu

Abstract:

In a bid to recover lost energy in the gas turbine and improve efficiency, many modifications to power plants have been made. The COGAS plant is one of such modifications to existing power plants. Due to the high efficiency obtained from such plants theoretically, it is seen that the COGAS plant is of immense benefit for practical applications. However, there exists no chart or Table that predicts the efficiency of the COGAS plant at any operating condition since two COGAS plants of the same specification can provide different efficiencies when operated in different regions or places e.g. (Canada in winter and Nigeria in Harmattan). Thus basic parameters of the COGAS plant were examined as to further understand their effect and enhance efficiency. This analysis was achieved using VB.Net computer programming language and data collected from gas and steam turbines on industrial duty for electricity generation. The result is a Table similar to the presently existing thermodynamic steam Table which will assist designers and engineers to pick optimum parameters with a targeted efficiency and place of operation in mind.

Ultrasonic characterization of frequency dependent attenuation properties of plaster boards

Asafaa T. B.

Abstract:

Plaster boards are heterogeneous materials with quite substantial degree of attenuation when exposed to ultrasonic waves. The attenuation properties are determined from the frequency shifts induced by the presence of scatterers within the material continuum. In this work, ultrasonic principle is used to estimate the frequency shifts in three different plaster boards-Cement board (CB), Glass Fiber Reinforced Gypsum (GRG) and Exterior Glass fiber Reinforced Gypsum (EGRG) - for the purpose of attenuation characterization. 49 signals, obtained via ultrasonic backscattered echo technique, were extracted from the samples of each material with contact mode Harisonic 2.25MHz transducer connected to the workstation. These signals are processed via time domain and optimized homomorphic analyses. Histograms of the time domain results indicate a general shift towards the low amplitudes and non-uniform shift magnitudes are observed in each sample and across the three materials. The skewness and standard deviation of the frequency shifts clearly show some fundamental differences in scattering and absorption nature of these materials. Downwards shifts in the centre frequencies compared to the steel reference material are equally significant. The mean center frequencies are found to be 2.3891, 2.2695 and 2.2102MHz for CB, GRG and EGRG respectively indicating lowest attenuation in CB. Also, attenuations are found to increase with increase in frequency within the limit of the transducer bandwidth of 2.0286 and 3.4402 MHz. Tests of repetitions confirm that the observed frequency changes are due to sample non-uniformity and not signal processing artifacts.

Role of partially bumpy surface to control the flow separation of an airfoil

Md. Abdullah Al Bari, Mohammad Mashud and Hasan Ali

Abstract:

The aim of the research is to control the flow separation of an airfoil by providing a partial bumpy on the upper surface. In order to obtain the highest levels of performance efficiencies for mission varying aircraft, it is necessary to either: (a) alter the boundary layer behavior over the airfoil surface-flow control methods of interest here, and/or (b) change the geometry of the air- foil real time for changing free stream conditions-adaptive wing technology. Geometry of the airfoil can be changed by providing bumpy on the upper surface. To investigate the effect of introducing large scale surface roughness through static curvature modifications on the low speed flow over an airfoil, two types model are prepared. One is regular surface model another is bumpy surface model. All the models are prepared by wood and the experiments are conducted using 36×36×100 cm subsonic wind tunnel. From the experimental investigations it has been observed that the flow separation on the airfoil can be delayed by using the bumpy on the upper surface. Flow separation occurs at 8° angle of attack in the smooth surface. But in bumpy surface it occurs at 14° angle of attack. That indicates the bumpy surface successfully controls the flow separation and increases the lift force of an airfoil.

Mixed refrigerants suitability analysis using artificial neural networks

N. Austin, P. Senthilkumar and S. Purushothaman

Abstract:

This paper presents an artificial neural network approach with back propagation algorithm (BPA) to find an alternative to Chloroflurocarbon (CFC) by considering the mixture of Hydro fluorocarbon (HFC) and Hydrocarbon (HC). The thermodynamic properties of refrigerants are obtained usinf REFPROP 9. Correspondingly, the Coefficients of Performances (COPs) of the mixed refrigerants have been obtained. The testing of the ANN shows high performance in estimating the closest COP.

Review on analysis and optimization of hydraulic cotton lint bailing press

A. G. Naik and N. K. Mandawgade

Abstract:

Ginning is the process of separation of fiber from cottonseed. Composite ginnery performs ginning and pressing operations to convert lint cotton into a bale. In modern day, capacity of ginning plant is such that the cotton bale handled by their press system gives rise to very large forces. Frame structure like all the other equipment has to be able to withstand these forces without damage. It is essential that the calculations for mechanical strength to check the suitability of top and bottom frame and their supports for hydraulic forces in cotton bale press at required level and duration in the system. The present paper is a review of the FEA analysis techniques of framed structure used in the recent past.

Artificial bee colony optimization for the combined heat and power economic dispatch problem

R. Murugan and M. R. Mohan

Abstract:

Numerical solution for the design of minimum length supersonic nozzle

Md. Hasan Ali, Mohammad Mashud, Abdullah Al Bari and Muhammad Misbah-Ul Islam

Abstract:

Minimum length of the supersonic nozzle has been calculated for the optimum Mach number at the nozzle exit with uniform flow at both converging and diverging section of the nozzle. The calculation has been carried out based on the method of characteristics. Numerical solution is established for the two-dimensional, steady, in viscid, irrotational and supersonic flow. It is rational to assume the flow holds the consistency in the converging section and, thereby, an arbitrary shape is assumed for the converging section of the converging-diverging nozzle. The design considerations are concentrated at the diverging section.

Access control in cloud computing environment

Abdul Raouf Khan

Abstract:

Cloud computing is one of the emerging technologies. The cloud environment is a large open distributed system. It is important to preserve the data, as well as, privacy of users. Access Control methods ensure that authorized user’s access the data and the system. This paper discusses various features of attribute based access control mechanism, suitable for cloud computing environment. It leads to the design of attribute based access control mechanism for cloud computing.

Modeling and simulation based approach of photovoltaic system in Simulink model

M. Abdulkadir, A. S. Samosir and A. H. M. Yatim

Abstract:

Land information system (LIS)-based digital photogrammetry for mapping

Nadia Mahmood Ahmad

Abstract:

Photogrammetry-supported GIS is concerned with the accuracy of the data used in GIS offering ways of direct visualization and easier interpretation in a real-world scale. Matching the mosaic images usually implies that the radiometric intensity data from one image representing a particular feature must be matched to the intensity data from the second image, representing the same feature. After the production of mosaic for the study area, stereo pair of the final form the ArcView software was used to prepare a digital map with multi layers. The layers, which were 12 layers formed: college of science, architecture department, college of politics, college of engineering, Engineering labs, Lectures halls, Collection of college’s buildings, Service buildings, Main roads, Pedestrian roads, The parks, Gardens. After the completion of the drawing layers have been producing digital map in its final form with full database and some statistical analysis.

Abstract:

Nine radial vertical electrical soundings (RVES) were carried out around Ifon, Southwestern Nigeria, to determine the electrical anisotropy and map the trend of concealed structures. The results show that the concealed bedrock is anisotropic with the causative structural features comprising joints, foliations and faults. Dual structural trends observed at four of the RVES station were interpreted as intersection of structural elements at depth. The coefficient of anisotropy varies from 1.03 to 2.4 with a mean of 1.3. The bedrock resistivity shows an inverse relationship with the coefficient of anisotropy and localities with low bedrock resistivity may consequently indicate a fractured zone, which could favour groundwater storage. This is also true of sites with dual structural trends, where the interconnected structures aided groundwater movements.