Exploratory study of periwinkle shells as coarse aggregates in concrete works

A. P. Adewuyi and T. Adegoke

This paper reports the exploratory study on the suitability of the periwinkle shells as partial or full replacement for granite in concrete works. Physical and mechanical properties of periwinkle shells and crushed granite were determined and compared. A total of 300 concrete cubes of size 150 x 150 x 150 mm3 with different percentages by weight of crushed granite to periwinkle shells as coarse aggregate in the order 100:0, 75:25, 50:50, 25:75 and 0:100 were cast, tested and their physical and mechanical properties determined. Compressive strength tests showed that 35.4%  and 42.5% of the periwinkle shells in replacement for granite was quite satisfactory with no compromise in compressive strength requirements for concrete mix ratios 1:2:4 and 1:3:6, respectively. This corresponds to savings of 14.8% and 17.5% for 1:2:4 and 1:3:6 concrete mixes, respectively.

Control setting of unified power flow controller through load flow calculation

Ch. Chengaiah, G. V. Marutheswar and R. V. S. Satyanarayana

Controlling power flow in modern power systems can be made more flexible by the use of recent developments in power electronic and computing control technology. The Unified Power Flow Controller (UPFC) provides a promising means to control power flow in modern power systems. Essentially, the performance depends on proper control setting achievable through a power flow analysis program. This paper aims to present a reliable method to meet the requirements by developing a Newton-Raphson based load flow calculation program through which control setting of UPFC can be determined directly. A MATLAB program has been developed to calculate the control setting parameters of the UPFC after the load flow is converged. Case studies have been performed on IEEE 5-bus system to show that the proposed method is effective. These studies indicate that the method maintains the basic NRLF properties such as fast computational speed, high degree of accuracy and good convergence rate.

Critical properties of hydrocarbon mixtures by artificial neural network and Peng-rob EOS

S. M. Hosseini, A. R. Fazlali and G. R. Zahedi

The calculation of critical properties of the petroleum fluids is important for practical and theoretical reasons. Experimental measurements of critical properties are time consuming, costly and very difficult. Therefore, they are often predicted using empirical correlations or thermodynamic models that can be calculated with moderate accuracy only up to pressures and temperatures near the critical region of the mixtures. In this model an Artificial Neural Networks (ANN) approach for the estimation of the critical properties of hydrocarbon mixtures is used. The typically collected experimental data after pre-scaling were used for the training and testing of the Artificial Neural Network. The results show very good capability of ANN to predict the data. Among the ANN's training, the Radial Basis Function (RBF) method gave the best prediction performance. The ANN model was also compared with the experimental data, and the data which was calculated based on the Peng-Robinson equation of state. The comparison confirmed the superiority of the ANN model.

Prediction of PVT properties of ammonia by using artificial neural network and equations of state

Amir Sharifi, Abdolreza Moghadassi, Fahime Parvizian and Sayed Mohsen Hosseini

Ammonia is an important gas that plays significant role in many processes. Consequently, knowledge of the thermodynamic properties of Ammonia is necessary for the interpretation of physical and chemical processes. A new method based on Artificial Neural Networks (ANN) for prediction of thermodynamic properties has been proposed for both superheated and saturated region of Ammonia. For this development, the data sets that collected from Ammonia thermodynamic table [Perry’s Chemical Engineering Handbook] were used. After training the networks, the models were tested by unseen data to evaluate their accuracy and trend stability. Among this training the back-propagation learning algorithm with various training such as Scaled Conjugate Gradient (SCG), Levenberg-Marquardt (LM) and Resilient Backpropagation (RP) methods were used.  The best suitable algorithm with appropriate number of seven neurons in the hidden layer which provides the minimum Mean Square Error (MSE), 0.0000900135, is found to be the SCG algorithm. Then ANN's results were compared with results of some equations of state such as Lee Kesler, NRTL, Soave-Redlich-Kwong and Peng Robinson. Comparisons showed the ANN capability for prediction of the thermodynamic properties of Ammonia.

Combined economic and emission dispatch using evolutionary algorithms-A case study

A. Lakshmi Devi and O. Vamsi Krishna

An efficient and optimum economic operation of electric power generation systems has always occupied an important position in the electric power industry. This involves allocation of the total load between the available generating units in such a way that the total cost of operation is kept at a minimum. In recent years this problem has taken a suitable twist as the public has become increasingly concerned with environmental matters, so that economic dispatch now includes the dispatch of systems to minimize pollutants, as well as to achieve minimum cost. This paper proposes a lambda based approach for solving the Combined Economic and Emission Dispatch (CEED) problem using Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) methodologies considering the power limits of the generator. The purpose of Combined Economic and Emission Dispatch (CEED) is to minimize both the operating fuel cost and emission level simultaneously while satisfying load demand and operational constraints. This multi-objective CEED problem is converted into a single objective function using a modified price penalty factor approach.

Solar photocatalytic treatment of phenolic wastewater- potential, challenges and opportunities

S. Shanmuga Priya, M. Premalatha and N. Anantharaman

Abstract:

Quantity of water use in Indian industries is very high compared to other countries water usage. Inefficient water use by industry in India creates lot of problems. This quantity could be reduced to a minimal by recycling the water after sufficient treatment. The available treatment processes do not aim at sufficient treatment required for recycling of water but it concentrates more on achieving the standards, hence complicating the process. Complicated Effluent Treatment process neither helps in recycling of water nor getting standards achieved but results in higher energy consumption for Effluent Treatment Plant. This work aims at sufficient in-situ treatment of wastewater and recycling of water for low-grade applications in the industry. Complete destruction of the contaminant is possible using inexhaustible, free source of energy from sunlight thus consuming very less primary energy for its operation. Photocatalytic experiments were carried out using laboratory photo reactor for degradation of phenol wastewater. The experiments were carried out with 0.2 g/L of TiO2 catalyst for different concentration of phenol wastewater ranging from 20, 50,100,200,300,400 and 600 ppm. It is found that complete degradation of phenol is possible in a reasonable time (i.e. less than 5 hrs) when concentration of phenol is ≤100 ppm. The paper also reviews the potential, opportunities and challenges of solar photocatalytic wastewater treatment for Indian environmental conditions.

Gasoline production from palm oil via catalytic cracking using MCM-41: Determination of optimum condition

Dessy Y. Siswanto, Giyanto W. Salim, Nico Wibisono, Herman Hindarso, Yohanes Sudaryanto and Suryadi Ismadji

The catalytic cracking of palm oil involves parallel cracking reactions which produce organic liquid product (OLP), non-condensable gas and coke. OLP consists of gasoline, kerosene and diesel, all can be used as alternative fuels. The objective of this study was to determine the effect of operating conditions: oil to catalyst (O/C) ratios and Weight Hourly Space Velocities (WHSVs)) to the feed conversion, OLP yield and gasoline yield. The optimum conditions of OLP production was also obtained in this study. The experiment was conducted in a fixed bed microreactor at a temperature of 450°C. The WHSVs were varied at a range of 15 to 25 h^-1.While the O/C ratios were varied at the range of 30 to 50. The results show that the highest yield of OLP was 60.73 wt% at O/C ratio of 32.50 and WHSV of 19.38 h^-1.

Synthesis and characterization of some Diorganotin(iv) complexes of N-tolyl- m-Nitrobenzohydroxamic acid

Abdualbasit Graisa, Yang Farina, Emad Yousif and Mohamed Kassem

Abstract:

New diorganotin(IV) complexes of the type Ph₂SnL₂, Bu₂SnL₂ and Me₂SnL₂ of the ligand N-tolyl m-Nitrobenzohydroxamic acid. Ligand formed by condensation reaction of 3-Nitrobenzoyl chloride with N-tolyl hydroxylamine in presence of sodium hydrogen carbonate as a catalyst. The prepared complexes were characterized by FTIR Spectroscopy, electronic spectroscopy, ^1HNMR and ^13CNMR. From the spectral measurements, monomer structures for the complexes were proposed. Octahedral geometry was proposed for the complex prepared.

Consolidation behavior of piles under pure lateral loadings

Qassun S. Mohammed Shafiqu

Abstract:

The results of two-dimensional finite element analysis of piles under pure lateral loadings in saturated porous medium are described herein. The soils are characterized using the Mohr Coulomb model in which together with the finite element formulation are described and verified.  Transient analysis of pile problem is then carried out, and the results of the analysis are presented which demonstrate the effects of the consolidation process on the lateral response of the pile under lateral loadings. Lower lateral loading gives lower differences in deformations with time and being significant with increasing load. Also lateral soil pressure and shear stress in soil increased with time and depth but in a rate lowered as the lateral load decreased.

Particle trajectories in a three phase common enclosure gas insulated busduct with Monte Carlo technique

M. Venu Gopala Rao, J. Amarnath and S. Kamakshaiah

Abstract:

The excellent insulation properties of compressed sulphur hexaflouride are adversely affected by metallic particle contamination in practical gas insulated systems. The movement of such particles is random and the particles play a crucial role in determining the insulation behavior of GIS. A Three-phase enclosure-type gas insulated bus (GIB) has widely been applied to minimize the installation space of a substation. To determine the particle trajectories in a three-phase common enclosure Gas Insulated Bus duct (GIB) an outer enclosure of diameter 500 mm and inner conductors of diameters 64 mm spaced equilaterally are considered. Aluminum, copper and silver particles were considered to be present on enclosure surface. In order to determine the random behavior of moving particles, the calculation of movement in axial and radial directions was carried at every time step using rectangular random numbers. Simulation of Particle Movement with Reduced Phase Conductor is also carried out with a view to obtain optimum size of conductor for reliable operation by reducing the original diameter of the conductor from 64mm to 54mm in steps of 5 mm. At each reduced diameter the particle movement is calculated at each instant in both radial and axial directions using Monte Carlo Technique. Monte Carlo simulation is also carried out by changing the random solid angle from 1 degree to 0.5 degrees. The random solid angle is decreased to 0.5 degrees to take into account more smooth end profile of the particle. It is observed that a lower solid angle random movement yields a lower axial movement. It therefore suggests that a more smooth ended wire will have lesser axial movement than a sharp cut wire like particle.

Technical challenges on Microgrids

A. A. Salam, A. Mohamed and M. A. Hannan

Abstract:

Microgrids are becoming increasingly attractive to consumers and as such in the future, a great number of them will be installed at consumer’s sites. In this situation, conventional distribution networks that accept distributed generation connections may face serious difficulty when its control and protection functions become more complicated. This incurs a burden to the network operation and some technical limitations will appear when a great number of distributed generations are installed.  One way of overcoming such problems, a micro grid system is formed to provide reliable electricity and heat delivering services by connecting distributed generations and loads together within a small area. A microgrid is usually connected to an electrical distribution network in an autonomous way and employs various distributed generation technologies such as micro-turbine, fuel cell, photovoltaic system together with energy storage devices such as battery, condenser and flywheel. Micro grids can cause several technical problems in its operation and control when operated as autonomous systems. This paper is a review of three technical challenges on micro grid with respect to voltage and frequency control, islanding and protection of microgrids.

Prediction of elactic properties of FRP composite lamina for longitudinal loading

Syed Altaf Hussain, B. Sidda Reddy and V. Nageswara Reddy

Abstract:

A structural composite is a material system consisting of two or more phases on a macroscopic scale, whose mechanical performance and properties are designed to be superior to those of constituent materials acting independently. FRP composites are slowly emerging from the realm of advanced materials and are replacing conventional materials in a variety of applications. However, the mechanics of fiber-reinforced composites is complex owing to their anisotropic and heterogeneous characteristics. The mechanical properties E₁,E₂,υ₁₂, and G₁₂ are determined for three different types of  FRP (Glass/Epoxy composite, Graphite/Epoxy composite and Kevlar/Epoxy composite) unidirectional continuous fiber lamina at different fiber volume fractions  using the finite element method. A finite element model incorporating the necessary boundary conditions is developed and is solved using commercially available FEA package. The results are compared with analytical solution possible.

Voltage stability constrained ATC computations in deregulated power system using novel technique

P. Gopi Krishna and T. Gowri Manohar

Abstract:

The voltage stability constrained Available Transfer Capability (ATC) computations are obtained on IEEE 9-bus by running load flow until the voltage collapse point is achieved by enhancing the load in steps with constant power factor. These results are used to train the Neural Network by using Radial Basis Function Neural Network (RBFN) technique. The comparative results of convergence method, L-index method and RBFN network are presented in this study. The results are certainly useful in an online environment of deregulated power system in view of computational simplicity, time and computer memory.

Finite element analysis of consolidation problem in several types of cohesive soils using the bounding surface model

Qassun S. Mohammed Shafiqu

Abstract:

Finite element analyses of consolidation problem in several types of saturated cohesive soils were performed using the elastoplastic bounding surface model. In this paper, the model and the finite element formulation were described and examples of model prediction and accuracy of the finite element formulation were given. The transient response of the saturated porous media is based on Biot’s theory of consolidation. Transient analysis of a two-dimensional consolidation problem involving a flexible strip footing on a clay layer of finite thickness is then carried out which demonstrate the effects of consolidation process and model parameters on the pore pressure response and ground movements under the strip footing.