Development of a dual powered palm fruit stripper

Ologunagba F. O., Ojomo O. A. and Lawson O. S.

A palm fruit stripper that is dual powered was designed, fabricated and tested. When manually powered, the machine has a throughput capacity of 0.612 tonne/hr, stripping efficiency of 68.9% and quality performance efficiency of 47.4% at a sterilization time of 90 minutes. When powered by an electric-motor and tested at three beater speed (250, 350 and 450rpm) with quartered bunches sterilized at 30, 60 and 90 minutes, the machine gave its best work performance at 450rpm and sterilization time of 90 minutes. The maximum throughput capacity, stripping and quality performance efficiencies were 2.14 tonne/hr, 96.1% and 81.9%, respectively. The cost of producing one unit of the palm fruit stripper as at the time of fabrication was estimated to be eighteen thousand, three hundred and fifty naira (N18,350) not including the cost of electric motor and the power required when operated with electric motor was 2.25kw.

Effect of plastic fines on over consolidated mining sand

Thian S. Y. and C. Y. Lee

In-situ Malaysian soils in tin mining areas usually occur as mixtures of sand and clay in widely varying proportions. Their engineering behaviour is different from that of clean mining sands. Natural soils are often in a structured and over consolidated state. It was found that the rate of loss of pre-consolidation history in sand is much faster than that in clay. This paper addresses the effects of plastic fines on the shear strength behaviour of over consolidated mining sands. An experimental investigation on samples of reconstituted clean mining sand containing different proportions of plastic fines was carried out. The samples were subjected to undrained triaxial compression tests under various levels of mean effective consolidation stress and unloaded to 100 kPa during shearing to achieve the OCR required. The stress-strain-pore pressure response, peak strength and soil stiffness were measured and evaluated for each plastic fines percentage in the over consolidated soil samples.

Fluid flow in a rigid wavy non-uniform tube: application to flow in renal tubules

P. Muthu and Tesfahun Berhane

In this paper, the problem of steady, viscous, incompressible fluid flow in a tube of slowly varying cross-section with absorbing wall is studied. For the mathematical formulation of the problem the effect of fluid absorption through permeable wall is accounted by prescribing flux as a function of axial distance and the fluid is considered as a Newtonian fluid. The nonlinear equations of motion are linearized by perturbation method by assuming δ (ratio of inlet radius to wavelength) as a small parameter and the resulting equations are solved by numerical methods. The effects of reabsorption coefficient (α), slope parameter (k) and amplitude ratio (ε) on the velocity profiles mean pressure drop and wall shear stress are presented graphically. Results indicate that the variation of slope parameter and reabsorption coefficient influences the flow field considerably.

Application of Taguchi method for the resistance spot welding of the galvanized steel

A. G. Thakur, T. E. Rao, M. S. Mukhedkar and V. M. Nandedkar

Resistance Spot Welding (RSW) is a process that is being used in the industry for sheet joining purposes especially in the Automobile and Aerospace industry. The problems associated with RSW are tendency of alloying with the electrode resulting in increased tool wear, and subsequent deterioration of weld quality. More current and time leads to expulsion and over heating of the electrode affecting the weld quality and less value results in insufficient weld strength. The complicated behavior of this process must be analyzed to set the optimum parameters to get good quality weld. This paper presents an experimental investigation of the effect and optimization of welding parameters on the Tensile Shear (TS) strength in the RSW of Galvanized steel. RSW of galvanized steel is always difficult due to tendency of zinc coating alloying with electrode. The experimental studies were conducted under varying welding current, welding time, electrode diameter and electrode force. Taguchi quality design concepts of L27 orthogonal array has been used to determine S/N ratio (db), Analysis of Variance (ANOVA) and F test value for indicating most significant parameter affecting the spot welding performance. The experimental results confirmed the validity of used Taguchi method for enhancing welding performance and optimizing the welding parameter in RSW process. The confirmation test indicated that it is possible to increase tensile shear strength significantly using Taguchi method.

Suggesting areas for detailed investigation of mineral occurrences in Nigeria for national resource database

Ajaka E.O. and Oyathelemi E.O.

Abstract:

The economy of Nigeria is not solid minerals driven like that of a country like South Africa. Although several mineral occurrences have been identified in the country, their actual mode of occurrence, mineralogical composition and reserves are not known. This article reviewed the pattern of occurrence of the presently known mineral ores in Nigeria with a view to suggesting a pattern for detailed investigation for accurate chemical and mineralogical compositions and ore reserve estimation for easy investment planning. The results revealed a specific pattern of occurrence of some minerals or group of minerals in some geographic locations in the country. The presently known mineral ores are drawn in maps to present a pictorial view of their pattern of occurrence. It is found that this known pattern could be used to undertake a less expensive detailed investigation of these mineral deposits to create a reliable database of their actual compositions and reserves.

Finite element analysis of radiation and mass transfer flow past semi- infinite moving vertical plate with viscous dissipation

V. Srinivasa Rao and L. Anand Babu

Abstract:

The objectives of the present study are to investigate the radiation effects on unsteady heat and mass transfer flow of a chemically reacting fluid past a semi-infinite vertical plate with viscous dissipation. The method of solution can be applied for Finite element technique. Numerical results for the velocity, the temperature and the concentration are shown graphically. The expressions for the skin-frication, Nusselt number and Sherwood number are obtained. The results show that increased cooling (Gr>0) of the plate and the Eckert number leads to a rise in the velocity. Also, an increase in the Eckert number leads to an increase in the temperature, whereas increase in radiation parameter lead to a decrease in the temperature distribution when the plate is being cooled.

Structural failures of earth dams in Nigeria: a case study of cham dam in Gombe state

Umaru A., Ogedengbe K. and Omobowale M.O.

The study investigates the reasons for failure of earth dams in Nigeria with emphasis on dams owned by the River Basin Development Authorities of the Federal ministry of Agriculture and Water resources using Cham dam in Gombe State as case study. The general causes of earth dam failure were considered with emphasis on failures due to engineering factors. Cham dam failed in September 1998 after commissioning in December 1992 as a result of poor planning, inadequate study, inconsistent design, un-engineered construction and lack of dam safety monitoring team at site. Based on the findings, suggestions were given on how earth dam failures in Nigeria can be minimized in terms of adequate feasibility studies, good design, appropriate construction and an improved maintenance culture.

Development of a surface roughness prediction system for machining of hot chromium steel (aisi h11) based on artificial neural network

Rajesh Rai,   Arun Kumar Shrikantha S Rao and Shriram

Abstract:

In this paper, an attempt is made to apply the principles of artificial neural networks (ANN) towards developing a prediction model for surface roughness during the machining of high chromium steel through face milling process. Now a days, hot chromium steel is prominently used in die and mould industry as well as in press tools, helicopter rotor blades, etc... Initially, Taguchi design of experiments was applied while conducting the experiments to reduce the time and cost of experiment. Multilayer perceptron (MLP) network using Feed Forward Error Back propagation was chosen as the Neural Network architecture to describe the process model. The experiments were conducted on a C.N.C milling machine using carbide cutters. Pearson correlation coefficient was also calculated to analyze the correlation between the system inputs and selected system output i.e. surface roughness. The results of ANN modeling were substantiated by testing and validation of the resulting surface roughness values and the results have been encouraging. The outputs of Pearson correlation coefficient also showed a strong correlation between the feed per tooth and surface roughness, followed by cutting speed.

Strengthening of jiamusi pre-stressed concrete highway bridge by using external post-tensioning technology in China

Ali Fadhil Naser and Wang Zonglin

Abstract:

External post-tensioning is defined as a system in which the pre-stressing tendons or bars are located outside the concrete section. The pre-stressing force is transferred to the member section through the end anchorages, deviators or saddles. The objectives of this study are to strengthen Jiamusi pre-stressed concrete highway bridge by using external post-tensioning tendons, to determine the internal forces, and to design the external post-tensioning system. Two software are used in the analysis of the T-shaped cantilever structure and anchor beam. The first is Dr. Bridge software Ver. 3.1, and the second is Ansys software Ver. 10. The results of analysis before and after laying the leveling layer of the bridge deck pavement show that the section of T-shaped cantilever structure can satisfy the demand of vehicle-20 grade and vehicle-50grade grade. The compressive stress of the upper edge of pier top box section is small, it is only 1.91Mpa. Therefore, there is need to strengthen the top of the bridge deck. External post-tensioning tendons are used to strengthen the bridge deck. The selection of external post-tensioning tendons depends on the ASTMA416-90A specification. The external tendons consist of high strength, low relaxation strands, and the standard tensile strength is 1860MPa. The design and construction of external post-tensioning system includes the design and construction of anchor beam which includes the design of re-bars and the design of damper devices, and the layout of external post-tensioning tendons along the bridge deck.

Preliminary determination of asphalt properties using microwave techniques

Ratnasamy Muniandy, Md. Maniruzzaman B. A. Aziz, Khazani Abdullah, Ahmad Rodzi Mahmud, Kaida Khalid and Alyani Ismail

Abstract:

An accurate, contactless and non-destructive method has been developed to characterize the rheological properties of asphalt (bitumen) by applying microwave techniques. The measured microwave parameters can be related to material parameters as microwaves are affected by means of wave transmission through the asphalt medium. In lossless and lossy dielectrics, diverse properties such as porosity, material composition, uniformity of the material, delamination of layers, moisture and contamination content and many other properties can be measured by suitable modeling and calibration of measuring technique. Microwave parameters can be correlated with conventional test and Strategic Highway and Research Program (SHRP). Preliminary test results indicate a good co-relation with material properties. Classical methods, which are time consuming, costly and empirical can be replaced by this new microwave method. This will bring a revolutionary change in world highways and transportation sector.

Evaluation of gasifier based power generation system using different woody biomass

Surendra R. Kalbande, Mrudulata Deshmukh, Harsha M. Wakudkar and Gajanan wasu

Abstract:

Biomass based power generation system having power rating of 10 kW was established at Department of Unconventional Energy Sources, College of Agricultural Engineering and Technology, Dr. Panjabrao Deshmukh Agriculture University, Akola. The system was evaluated for power generation using Prosopis juliflora (Vilaytee babool) and Leucaena leucocephala (Subabool) wood. Specific biomass consumption was found to be decreased from 3.9 to 1.7 kg/kWh at different loading conditions. Thermogram of Leucaena leucocephala and Prosopis juliflora are found better for getting sufficient amount of tar in case of gasification of this material. The quantum of lighter volatile for Leucaena leucocephala (Subabool), and Prosopis juliflora ranges from 55 and 52 %, respectively. Heavier volatile for Leucaena leucocephala (Subabool) and Prosopis juliflora during gasification range from 15 and 17%, respectively. However, on the basis of TGA analysis biomaterial can be gasified effectively.

A parametric study for the efficient design of corrugated blast wall panels used in petrochemical facilities

M. A. Faruqi, J. Grisel, A. Salem and J. Sai

Abstract:

Corrugated panels are currently used in petrochemical facilities as an economic means to provide blast protection to personnel and other valuable assets. In this paper, parametric studies were conducted on the various elements (e.g., compression flange, depth, angle of corrugation, etc.) of a corrugated blast wall using static nonlinear finite element analyses and dynamic nonlinear single degree of freedom analyses. During the static analyses, panel characteristics such as ductility and strength were explored and nonlinear load-deflection curves were generated. The load-deflection curves were then used to observe the response of each wall using a single degree of freedom time-step integration method.  Results showed that some blast wall profiles have a greater ability to limit reaction loads transferred to the primary structure, reduce material cost / panel thickness, and/or protect nearby assets (deformation control). The results contained herein define specific dimensional ratios for elements that will result in a favorable response. Understanding how the different elements of a corrugated blast wall affect its structural response to a blast enables the engineer to design efficient passive protection systems that dissipate blast energy efficiently.

Effects of diurnal temperature dynamics on curing of cold-emulsion reclaimed asphalt pavements

Kiplagat Chelelgo

Abstract:

Strength development in Cold-Emulsion Reclaimed Asphalt Pavements is gradual and largely dependent on the rate at which curing proceeds. Its early life strength is therefore low and presents a major challenge in material specification for mechanistic pavement design. The solution has been to subject a sample of the mixture to be used in the pavement to accelerated laboratory curing to the attainment of Equilibrium Moisture Content (EMC) condition. Fatigue and Stiffness parameters of the mix along with the chemical properties of the binder can be determined from the cured samples and results incorporated into the pavement design process. The emphasis is in the choice of a laboratory curing protocol that adequately simulates expected curing trends in the field. Protocols in popular use employ steady state curing temperatures to predict long term behaviour of Reclaimed Asphalt Pavements. This project set out to investigate the likely effects of seasonal variations and diurnal cycles in ambient temperatures on the engineering properties of Reclaimed Asphalt and the incorporated binders. To simulate the above phenomena, a predictive model was adopted in computation of high and low temperature peaks that can be expected in two pavements, one in the tropics and the other in a temperate region. The resulting sets of temperatures were used to cyclically cure Reclaimed Asphalt Pavement cores that were manufactured by artificially aging Dense Bitumen Macadam (DBM) in the laboratory and mixing it with a cationic bitumen emulsion. Another set of cores were subjected to steady temperatures as is the current practice. This acted as a control for the two cyclic temperatures under study. Use was made of a suite of tests available in the Nottingham Asphalt Tester (NAT) to determine stiffness and fatigue properties of the mix under the three treatments. Bitumen binders recovered at the end of curing was tested for penetration, softening point temperatures and percentage of Asphaltenes.  The findings pointed at a likelihood of severe treatment of asphalt samples by the existing laboratory curing protocols. Curing at a steady temperature led to a lower fatigue life, over estimation of early life strength and underestimation of long term strength of the cold asphalt. Low penetration values, high softening point temperatures and high percentages of Asphaltenes in bitumen from the cured samples attest to severe aging of the samples.

Experimental studies for surge voltage response of a power transformer model winding provided with metal oxide varistors

Mohd. Zahed Ahmed Ansari, G. R. Gurumurthy and J. Amarnath

Abstract:

Surge voltage distribution across a power transformer winding due to appearance of very fast rise transient overvoltages (VFTO) such as lightning surges consists of high voltage oscillations and the voltage distribution along the length of the winding can be highly non-uniform. In order to make the voltage distribution more uniform along the length of winding under these conditions, a method has been explored as an alternate to the conventional methods that are being used presently. This method consists of providing suitably designed metal oxide varistors (metal oxide surge absorbers) across sections of winding. The voltage - current characteristic of metal oxide varistor (MOV) is given by V = KI^β, where K and β are the constants of MOV. Experimental investigations have been carried out on a transformer model winding with MOVs provided across fifty percent and hundred percent of winding length to investigate surge voltage performance of these types of windings for appearance of lightning overvoltage (full impulse voltages) at line terminal of the model winding. Transformer windings with α values 5.6, 11.8 and 18.9 have been analyzed. The oscillographic records obtained with presence of identical MOVs (MOVs having similar characteristic constants K and β) or non-identical MOVs (MOVs having different K value and similar β) across transformer winding sections show appreciable reduction in surge voltages across sections of winding as compared to that obtained without MOVs.