The reasonable flow field is the key problem in cathode design and the foundation of process stability in electroChemical machining. In order to improve the efficiency of cathode designing and stabiLity of process in NC precision electroChemical machining of integer impeller, a method of applying Computational Fluid Dynamics (CFD) to aid designing flow field structure of cathode has been studied. The numerical model of the three-dimension flow field was built according to the geometrical model of interelectrode gap and cathode. Then the numerical simulation of 3-D flow field was performed by using the standard k-ε turbulence model when the turbulence state in electroChemical machining had been determined. The effect of cathode's structure on the electrolyte flow field was analyzed according to the results of numerical simulation. A series of results similar to the actual experimental results are obtained. The method deduced in this paper could be used to achieve high efficiency and low cost cathode design, and consequently a lot of "trial and error" cycles will be deduced.
Homotopy perturbation method is used for solving the multi-point boundary
value problems. The approximate solution is found in the form of a rapidly
convergent series. Several numerical examples have been considered to
illustrate the efficiency and implementation of the method and the results are
compared with the other methods in the literature.
This study investigates initiation of small cracks on dumble-shaped plate type specimens of 1060steel at the load ratio of R = 0 under varied cyclic stress amplitudes between 0.6 and 1.0 of yield stress usingthe Instron machine (model: 8501). Sinusoidal wave of a frequency of 10 Hz was used in the experiment. Theexperiment was conducted at a room temperature of 23ºC. Each test for different applied stress ranges wascarried out for 2×104 cycles. Microstructure and fractography of the fractured specimen were also analyzed.Nucleations of cracks were observed at Ferrite-Ferrite G rain Boundary (FFGB) as well as inside Ferrite GrainBody (FGB), but the FFGB location was preferred. Results show that the average length of FFGB cracks isfound larger than that of the average length of cracks initiated inside FGB at the same cyclic loading conditions.The formation of slip band inside grain body, slip band impingement at grain boundary and elastic-plasticincompatibility synergistically have significant influence on fatigue crack initiation in 1060 steel. Additionally,the formation of irregular voids inside slip bands, initiation and growth of small voids at grain boundary andthe subsequent joining of these with other voids were seen as specific characteristics of 1060 steel. It was alsoestablished that cracks nucleate both at grain boundary and inside grain body in 1060 steel in the investigateddomain of 0.6 to 1.0Fy.It was further established that the orientation of the grain body cracks at low stress levelis greater than 45º and the average angle of orientation of these cracks increases like that of grain boundarycracks with increased magnitude of stress range.
Some Growth parameters of Macrobrachium mcrobrachion from Luubara Creek in Ogoni Land, Niger Delta, Nigeria was studied for a period of two years (January, 2006 - December, 2007). The parameters were evaluated using different applications in the FiSAT package such as the Powell-Wetheral plot; the ELEFAN 1 Scan, and the Non-Seasonalized Version of the Von Bertalanffy Growth Function (VBGF) to ensure accuracy. Powell-wetheral plot gave estimates of L∞ as 81.53 mm TL), K was 2.06 per year, Z/K was 1.07 while the growth performance index, Φ was 4.01. The growth parameter obtained from the ELEFAN 1 Scan were L∞ = 83.36 mm; K =2.25 per year; Φ = 4.02 and Rn = 0.13. The growth parameters obtained for the non- Seasonalized Version of Von Bertanlanffy growth function (VBGF) were L∞ = 34.61 mm; K = 0.28 per year; = 0.26 w hile the growth performance index was 2.5.1. The results from the length - at - age data showed that L∞ = 40 mm K = 0. 38 per year and t0 = -0.71. The overall estimates are L∞ = 82.65 mm; r = 0.95; K = 1.98 per year; t0 = 0.48; z/k = 1.07; Φ = 3.9 and Rn = 0.14 gave estimates of L∞ as 81.53 mm TL), K was 2.06 per year, Z/K was 1.07 while the growth performance index, Φ was 4.01. The growth parameter obtained from the ELEFAN 1 Scan were L∞ = 83.36 mm; K = 2.25 per year; Φ = 4.02 and Rn = 0.13. The grow th parameters obtained for the non-Seasonalized Version of Von Bertanlanffy growth function (VBGF) were L∞ = 34.61 mm; K = 0.28 per year; = 0.26 while the growth performance index was 2.5.1. The results from the length - at - age data show ed that L∞ = 40 mm K = 0. 38 per year and t0 = -0.71. The overall estimates are are L∞ = 82.65 mm; r = 0.95; K = 1.98 per year; t0 = 0.48; z/k = 1.07; Φ = 3.9 and Rn = 0.14. For 2006 the mean predicted extreme length was 81.63 mm while 2007 it was 83.33 mm. The overall predicted mean extreme length for M. macrobrachion in Luubara creek was 82.48 mm (TL) while the mean observed extreme length was 81.37 mm. The probability of having this length is put at 95% and the condition i.e., interval is between is 76.63-93.51%. The observed total lengths had a mean of 79.5 m m in 2006 and mean of 83.25 mm in 2007.
This paper deals with the simulation and implementation of fixed capacitor thyristor controlledreactor system . The TCR system is simulated using MATLAB and the simulation results are presented. Thepower and control circuits are simulated. Laboratory model for the FCR – TCR system is implemented using89C2051 and it is tested. The current drawn by the TCR varies with the variation in the firing angle. Theexperimental results are compared with the sim ulation results.
This study investigates the effective stress - porosity relationship above and within the oil window in the Kimmeridge Clay Formation (KCF) in the North Sea Basin (UK) using effective stress and porosity determined from wireline logs and pore pressure data. Porosity was determined from an empirical porosity - sonic transit - time transform, calibrated using shale and mudstone core porosity measurements from Jurassic shales in the North Sea. Effective stress was determined from the total overburden stress and pore pressure. The total overburden stress was calculated by integration of the density log. The results show that porosity range between ~11-20% in the pre-generation zone but decreased to <5% within the oil window. Compaction coefficient ($) values above the oil window vary from ~0.08-0.09 M/Pa, but vary from ~0.05-0.06 M/Pa within the oil window implying that deeper burial and a high degree of chemical precipitation and cementation has created a stiff matrix giving rise to low $ values. The effective stress-porosity relationship above and within the oil window reflects a possible decrease in effective stress occasioned by increase in porosity in the pregeneration zone.
Woji-Okpoka Creek is situated in a strategic location in Port Harcourt, Rivers State, N igeria and itreceives domestic and industrial wastes from the Trans-amadi industrial Layout, main Port Harcourt abattoirand riverine communities. There is little information on the zooplankton of this creek. The study investigatedspecies composition, diversity, abundance and distribution of zooplankton as well as some physico-chemicalparameters that affect this organism. Zooplankton and surface water samples were collected monthly from May2004 – April 2006 at low and high tides from ten stations according to APHA methods. These were analysedfor temperature, turbidity, transparency, salinity, dissolved oxygen (DO), biological oxygen demand (BOD),pH and nutrients. Zooplankton was identified microscopically. Species diversity was calculated using standardindices. Data was analysed using analysis of variance, Duncan multiple range and descriptive statistics.Zooplankton demonstrated significant temporal variation (P<0.05). A total of 85 species dominated bycopepods (43.4%) were identified. Diversity indices for copepods were: 1.0±0.03 (Margalef) and 0.5±0.02(Shannon). Water temperature 28.6±0.06cC, turbidity 3.6±0.32 NTU and transparency 0.7±0.01m showedsignificant temporal variations (P<0.05). Water chemical parameters were: salinity, 14.4±4.67‰; DO,5.0±0.10mg/l; BOD, 3.3±0.09mg/l and alkalinity, 84.1±1.41mg/l. Phosphate and ammonia exceeded FEPA andUSEPA acceptable levels for natural aquatic bodies. Phosphate demonstrated significant spatial variation(P<0.05). The presence of dominant copepods indicates an environment under stress. The domestic andindustrial effluents should be recycled or and treated instead of being discharged into this creek.
The most effective economical baking conditions w ere determined for foundry cores bonded with the grade 3 Nigerian acacia species exudates. Silica sand base cores bonded with the material were oven baked at temperatures ranging from 160 to 250ºC for varying periods oven cooled and then subjected to tensile strength tests to ascertain the best baking conditions for different alloy castings. The experimental core specimens were in accordance with foundry test standard, shaped like figure number eight. They were tested with standard universal strength machine equipped with attachment for gripping the cores and an instantaneous meter from which the test values were read. The result were compared with established standard foundry core property table which showed that the class V iron/steel cores are best made with 3% acacia bonded silica sand baked at 160ºC for 1 h. For magnesium cores, sand bonded with 4.5% acacia baked at 160ºC for 1-2 h was optimum. For class IV iron/steel cores 4.5% acacia bonded sand baked at 180ºC for 1 hour was optimal. Sand bonded with 4.5% grade 3 acacia baked at 200ºC for 1.0-2.0 h was optimum for copper, aluminium, classes II and III iron/steel cores. Sand bonded with 8.0-13.0% grade 3 N igerian acacia species baked at 200ºC for 1.5-2 h was found most effective for class I iron and steel cores.
The aim of the study is to monitor indoor radon gas levels in dwellings in the Sakumono Estates and its environs in the G reater Accra Region of Ghana in order to assess the risk of exposure to the inhabitants, using the passive Solid State Nuclear Track Detectors (SSNTDs). The sampling and deployment of the detectors covered the predominant mode of dwelling structures, which are the flats, semi-detached, detached and cluster houses. The mean Radon concentration obtained was 10.18 Bq/m3, with an annual effective dose equivalent to the population determined to be 0.22 mSv/yr, assuming an occupancy factor of 0.5 for the modern estate dwellings and 0.3 for the cluster (“compound type”) houses. The maximum recorded concentration was 18.60 Bq/m3 in a semi-detached building, followed by a concentration of 18.05 Bq/m3, recorded in a flat located on the ground floor. The annual effective dose equivalent to each type of housing unit has been calculated and given as 0.25 mSv/yr for flats, 0.25 mSv/yr for semi-detached houses, 0.23 mSv/yr for detached and 0.15 mSv/yr for the cluster houses. The Radon gas levels obtained may not pose any appreciable risk to the inhabitants on the basis that the levels were low. The excess life time risk of any member of the group suffering from Radon gas induced lung cancer is approximately 0.02%. The Radon gas levels were cross-checked with an active dosimeter (Radon Scout Plus) and an average concentration of 10 Bq/m3 was obtained. Mean values for flats, semi-detached, detached and cluster houses were 9.33, 10.86, 9.30 and 9.30 Bq/m3 with medians of 7.87, 9.86, 9.27 and 9.29 Bq/m3, respectively.
The study carried out a periodic quantification of the amounts of metal ions accumulated in the bloodof Wistar albino rat pre- and post-operative the implantation of stainless steel (SS) arch bar used formaxillomandibular fixation and compares these with the amounts accumulated in the fur used as a bio-monitor.The concentrations of the corrosion products increased from the 3 to 6 weeks post-operative periods in theblood and fur. The total metal ions accumulated in the fur and blood of Wistar albino rat in vivo follows theranking Ni > Fe > Mn > Co > Cr. Ni shows a high affinity for the fur and blood. The concentrations of Co, Mnand Cr ions in the fur post-operative is indicative of the levels of these metal ions in the blood.
The aim of the study is to determine the concentrations of trace elements in Ghanaian shea nut and shea butter. As part of the study, measurements of the elemental composition of shea butter and shea nut samples were carried out by Neutron Activation Analysis (NAA) using the Ghana Research Reactor-1 (GHARR-1). Samples collected from local markets in the Northern region of Ghana and the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1547 Peach leaves were irradiated at the GHARR-1 facility. Validation of the method was done using NIST SRM Orchard Leaves (1571) under the same experimental conditions. Six trace elements (Na, Mn, Al, Cl, Ca and K) were detected with maximum concentration of Na found to be 15±1 mg/kg in SN5, Mn; 7.4±0.8 mg/kg in SN6, Al; 259±3 mg/kg in SN1, Cl; 666±27 mg/kg in SN1, Ca; 0.21±0.04 wt.% in SN4, K; 2.0±0.04 wt.% in SN1, Ce; 3.2±0.06 mg/kg in SN2, Se; 0.12±0.004 mg/kg in SN4, and Sc; 0.40±0.02 mg/kg in SN2 . The concentrations of the trace elements were within the limit laid down for safe human consumption.
Engine performance is strongly dependent on gas dynamic phenomena in intake and exhaustsystems. Careful design of the manifolds enables the engineer to manipulate the characteristics. The basicexhaust tuning mechanisms was described w ith respect to a two-stroke single-cylinder engine. Tuned adjustableexhaust pipe for use on two-stroke motorcycle was designed and tested. The dynamometer used incorporateda flywheel of appropriate moment of inertia to simulate the mass of the motorcycle and rider. The test procedureinvolved measurement of the flywheel speed during an acceleration phase resulting from opening the throttle.Calculation of the instantaneous flywheel acceleration gave a measure of the torque and power characteristics.The airflow based values of delivery ratio; trapping efficiency and charging efficiency were not measureddirectly but were culled from the fuel flow values and the Spindt computation of the exhaust gas analysis.Experimental test results were presented for power output, specific fuel consumption and engine-out emissions.The tuned exhaust system was found to improve fuel economy of the engine by 12%. The major engine-outemissions, HC and CO were reduced by a minimum of 27.8% and 10.7% respectively. An improved poweroutput of 15.8% increase was achieved. As a bonus, it w as also found that the exhaust noise was reduced.
Carbon nanotubes (CN Ts) are one of the most significant achievements of nano-technology because of his important applications in the design of electronic nano-devices. The study of their properties is therefore important. In this investigation the Density Functional Theory (DFT) of electron and the Hartree-Fock (HF) method are utilized to study the adsorption of nitrogen molecules on the surface of (4, 4) and (5, 0) carbon nanotubes. The electronic structure, single point and dipole moment of both nitrogen and carbon nuclei are thoroughly studied. The computational results, which includes, indicate that rich adsorption patterns m ay result from the interaction of nitrogen with the carbon nanotubes. Sometimes C-N bounds are formed via breaking C-C bounds and sometimes a carbon atom in the nanotube is replaced by a nitrogen atom. Sometimes nitrogen atoms are attracted to a C-C bound. In summary, the optimized adsorption rates are calculated. Gaussian 98 software has been used to carry out quantum chemistry calculations.
A methodology is proposed for predicting the formation and the development of the manufacturing residual stresses, this approach is based on the study of the evolution of the resin yield stress. In order to evaluate our method, a comparison has been made between the yield time (corresponding to the formation of a yield stress) and the gel time. A self-consistent model is used to determine the cure-dependent chemical shrinkage coefficient of the composite material. This model allows considering for the composite material behavior an anisotropic chemical shrinkage, which is not represented by a classical linear model. An experimental approach based on the peel-ply method is used to determine the distribution of the residual stresses through the thickness.
The objective of this study was to determine the levels of chloride, fluoride, hardness and alkalinity of water samples from Vaal River, Sharpeville and Bedworth lakes in the Vaal region of South Africa. Water samples from the lakes and river were analyzed for fluoride by ion chromatography while chloride and alkalinity and hardness measurements were by titrimetric methods. The results showed Vaal River water to contain low fluoride concentration when compared to Sharpeville and Bedworth lakes. Fluoride ion concentration was found to be below levels that could cause fluorosis in the region. Chloride ion concentration was an average of 200 mg/L while water alkalinity was an average of 230 mg/L. The pH values recorded strongly indicate the presence of dissolved ions in solution that contributes to alkalinity and hardness of the water in the region.
In this study, for the purpose of determining physical and aerodynamic properties, some varieties of wheat, barley, chickpea and lentil were used. The length, width, thickness, geometric mean diameter, equivalent sphere diam eter, sphericity, seed mass, bulk density, true density, projected area, terminal velocity, drag coefficient of each grain variety were determined. The theoretical terminal velocities of those grains were calculated by using equations corrected with the shape factor. For all the grains, theoretical terminal velocities were lower than the experimental values. The average experimental terminal velocity was found to be in the range of 7.52 to 8.14 m/s for wheat varieties, 7.04 to 7.07 m /s for barley varieties, 7.72 to 7.78 m/s for lentil varieties and 11.15 to 12.01 m/s for chickpea varieties. The drag coefficients of seeds according to projected areas in different positions and equivalent spheres were calculated. The drag coefficient in the position of the lowest projected area for all the grain varieties was higher than that in the other position.
The article considers the current situation of professionalism in the agricultural labor market of Iran and intends to analyze the feasibility of effective entrance of agricultural students in agricultural fields, one of the most important solutions for knowledge based agriculture fulfillment, based on the case study of students of University C ollege of Agricultural and Natural Resources of Tehran University. R esults of the analysis revealed that 96.8% of students came from cities, 65.2% had not any practical experience in farming operations and 84.9% of them had no experience in farmers advisory and training services. Totally, the research demonstrated that effective entrance of agricultural students in agricultural fields presently is not feasible and agricultural sector has tenacious bottlenecks in knowledge based agriculture accomplishment. Finally, the study suggests what is needed to occur in the Iranian agricultural higher education system in order to achieve a more effective student entrance and alumnus preparation.
The aims of this study are investigation of consumption, intensity and efficiency of fossil fuels and electricity energy in Iran's agriculture sector and emission of GHG and air pollutants and their social (damage) costs. D ata used in this study were obtained from ministry of energy and central bank of Iron in 1997- 2007. Input energy of fossil fuel and electricity in agriculture increased from 265.1 to 411.2 PJ in this period. Results show that the efficiency of using of fuels and electricity has not increased and increasing of social costs of GHG and air pollutants emission has been more than added value of agriculture sector. So, it is necessary that by increasing of technology level and replacement of age-old and depreciated machineries and equipments, appropriate management and increasing efficiency of fuel and electricity energy in macro level will cause decreasing negative effects of energy consumption.
The purpose of this study was to conduct a descriptive survey to study the attitudes and perceptions of Iranian farmers on the concepts and thoughts of sustainable agriculture and identifying effective factors on their attitude. The target population of this study consisted of 7314 Behbahan farmers of Khuzestan province of Iran. A sample consisting of 208 respondents was selected through Stratified Sampling. The instrument used for assessing the attitude of respondents on the concepts of sustainable agriculture was a questionnaire by reliability 0.78. Responses were grouped based on the differences in standard deviation of mean, which revealed that 73.4% of respondents had moderate attitude towards concepts of sustainable agriculture. The results of study showed that there is positive correlation between literacy, participation in extension courses, off-farm income, farmer's knowledge about sustainable agriculture, level of use of sustainable agriculture methods, extension contacts and job satisfaction and negative correlation between age, experience in agricultural activities, family size and agrarian land with attitude toward sustainable agriculture. According to result of regression the ‘extension contacts’, ‘Farmers knowledge about sustainable agriculture’, ‘Job satisfaction’ and ‘literacy’ are effective factors on farmers attitude toward sustainable agriculture and explained 52.6% of this scale.
The purpose of this research is to draw a-mathematical relationship between different positive point electrodes using air as the dielectric medium for small gap distance. Four electrodes with varying radius of curvature were used at gap distance ranging from 1 to 12.5 cm under the same atmospheric condition. These results were graphically analyzed after finding the fifty percent probability (V50%) of the breakdown voltage. Using the exponential form in expressing them, a general formula was derived for the breakdown voltage for sharply non-uniform field for small air gap distances. The humidity level was noted because of the varying humidity level of environment. The spark over voltage increases with humidity therefore the wet and dry bulb readings were taken before each experiment and the required correction factors were noted.
This study shows the effect of heat treatment on the torsion aspects of D2 alloy steel, in addition further analysis using ANSYS11 software w as used in investigation. Test specimens were prepared using high accurate machines (CNC) however, hardening at different austenite temperature (during hardening) namely 1070, 1040, 1010 and 980ºC was studied followed by tempering process at 540ºC . It was found that there was a direct relation between the micro hardness magnitude and the austenite temperature, the maximum was 66.1% that achieved at 1070ºC. This finding was significant because there is a great enhancement in the ability of D2 alloy steel to sustain high torsion loads, where the maximum was 191.1% that achieved at 1070ºC.
In this study the effect of temperature on the optimum fiber length for maximum gain of Erbiumdoped almino-germanosilicate, aluminum oxide and yattria-silicate glass, with fixed pump power. The optimumlength depends strongly on the temperature and increases as the temperature increases. The maximum gain alsodepends on the wavelength and power of the signal which validate our findings through distributed gainmeasurements and so optimum length too.
A core graded-index and erbium-doped concentration are studied and optimized for an Erbium-dopedFiber Amplifier (EDFA ) in a two-level model. Also the dependence of both core graded-index and erbiumdopedconcentration on temperature and wavelength of the signal guided are studied. There is evidence to showthat the core graded-index has obvious influence on the gain bandwidth of the EDFA and the erbiumconcentration has effect on the bandwidth of the amplifier also both core graded-index and erbium-dopedconcentration are approximate linear dependence on wavelength and temperature.
Aqueous methanol of Ceiba pentandra leaves extract was tested for antivenom activity against Echis ocellatus snake venom. Among parameters investigated include: LD50 of the Echis ocellatus snake venom, phospholipase A2 activity, percentage hemolysis. In vivo analysis of total protein content, white blood cells, pack cell volume and haemoglobin contents were also investigated. The result reveals that Echis ocellatus has an LD50 of 0.280mg/kg ± 0.065. Haemolysis due to venom has drastically reduced by the extract from 66% to 27.4%. suggesting that the extract is effective in reducing haemolysis in mice. The in vivo studies reveals that there were significant (p<0.05) decrease in packed cell volume, total protein and haemoglobin contents for the venom group and there was only slight changes in the venom/extract and control groups suggesting that the extract has some inhibitory effect on the venom activity. The purified phospholipase incubated with the extract demonstrated neutralization effect against the phospholipase A2 activity. The result has shown that Ceiba pentandra leaves extract possess potent snake venom-neutralizing capacity. The plant leaves extract could be use as an antidote for snakebite envenomation.
The objective of this study was to investigate the effects of Mangifera indica L. (mango) stem bark crude Aqueous Extract (AE) on the morphology and biochemical functions of the liver in wistar rats. Adult wistar rats used in the study were divided into 2 groups: Group 1 rats were untreated and served as control and Group 2 experimental rats were orally given 1 mL (100 mg) daily of aqueous extract for a period of 14 days. The body weight changes and the weight of the liver were measured and the serum aspartate aminotransferase (AST), Alanine Transaminase (ALT), Alkaline Phosphatase (ALP), Total Bilirubin (TB) and Conjugated Bilirubin (CB) levels were determined. There was no significant difference (p<0.05) in body weight gain between the two groups at the end of the experiment. The treated group had a significant decrease in liver weight (p<0.05) when compared with control. The treated group also had a significant increase in AST when compared with control. There were no significant increases in ALT, ALP and total bilirubin when compared with the control. The study suggests derangement of liver function and possible damage to the hepatocytes by the crude AE at this dose and duration.
In this study, we propose a new sub-word segmentation and recognition scheme, which is independent of font size and font type. D ifferent ways of recognition are attempted namely Neural N et, template matching and principal component analysis. Results show that the real problem in Arabic character recognition remains the challenging separation of sub-words into characters. The system is realized in a modularized way. The combination of the different modules forms the basis of a complete Arabic OCR system. A successful preprocessing stage is reported. Unlike Latin based languages, recognition of printed Arabic characters remains an open field of research.
The present-day traditional architecture of a place usually results from solutions to climatic problems through reasoning, countless experiments, experiences and accidents as well. This usually takes the efforts and perseverance of generations of builders who make use of whatever works for them while discarding what did not. The purpose of this study is to discuss the influence of climate, particularly rainfall, on Hausa Traditional Architecture. The objective is to bring out how the nature of rainfall has influenced the choice of building and roofing material and the architectural design of building in traditional Hausa society. The study examined the extent of the Hausa states in Nigeria and the location of Zaria. This is followed by a discussion on the climatic conditions in Zaria; the influences of rainfall on mud construction of foundations, walls and roofs. The study concludes with an overview of the resultant effect of this element of climate on the future of Hausa Traditional Architecture, with recommendations aimed at salvaging the situation.
When an ultra thin Silicon oxide film will been grown thermally on Si substrate, the clean oxide film could not be grown because of native oxide on the substrate and impurities such as carbon. Therefore some methods and experiments have been performed for grow ing SiO2 on Si (111) in presence and in absence of Ar gas at high pressure and high temperature. Experiments show that clean and amorphous nano oxide film could be formed at Ar media. Moreover, the film structures have been studied by using AES (Auger Electron Spectroscopy) and SEM (Scanning Electron Microscopy) techniques.
The objective of this research was to study the performance of cryogenically treated HSS drills for drilling gray cast iron. Drilling experiments were conducted with cutting speeds: 560, 710, 900, 1120 rpm, feeds: 0.05, 0.08, 0.12, 0.19 mm/rev and a constant drill diameter: 8 mm. The cryogenic treatment cycle consisted of cooling the test samples from room temperature to cryogenic temperature of -178.9ºC in 3 h, soaking at cryogenic temperature for 24 h and w arming to room temperature in about 5 h. The thrust force and torque were measured using drill tool dynamometer. The surface roughness (Ra, Rz, Rq and R t) of the drilled specimens were measured using talysurf. The experimental lay-out was designed using Taguchi’s Orthogonal Array technique. Signal-to-Noise Ratio analysis was performed to identify the effect of the parameters on the response variables. The treated drills were found superior to the non-treated in all the test conditions in terms of lesser thrust force, torque and also superior surface roughness of the specimens. The tool wear was studied using SEM.
Diesel engine is becoming increasing popular due to its high efficiency and durability. Considering the most important greenhouse gas, carbondioxide (CO2), the diesel engine is superior to gasoline engine. Unfortunately, the diesel engine emits high level of oxides of nitrogen (NOx). Close control of combustion in the engine will be essential to achieve ever-increasing efficiency improvements while meeting increasingly stringent emissions standards. As new degrees of freedom are created, due to advances in technology, the complicated processes of emission formation are difficulty to assess. Artificial neural network (ANN)-based engine modelling offers the potential for a multidimensional, adaptive, learning control system which does not require knowledge of the governing equations for engine performance or the combustion kinetics of emissions formation that a conventional map-based engine model require. This paper evaluates the capabilities of ANN as a predictive tool for multi-cylinder diesel engine NOx emissions. The experiments were carried out with a stationary light-duty Nissan diesel engine test-rig designed and assembled to allow testing of the engine in a laboratory environment. Standard laboratory procedures were used to measure the engine operating parameters and its tailpipe emissions. ANNs were trained on experimental data and used to predict the oxides of nitrogen (NOx) emissions under various operating variables. Fraction of variance (R2) and mean absolute percentage error (ξ) were used for comparison in the sensitivity analysis. The Levenberg-Marquardt (LM) algorithm with 11 neurons produced the best results. Among the examined combinations of learning criteria in different architectures of backpropagation (BP) designs, a set of 0.05, 0.05 and 0.3 for learning rate, momentum and weight respectively, gave the best-averaged accuracy. For pre-specified engine speeds and loads with LM algorithm, ξ were found to be between 0.68 and 3.34%.
Okpoka Creek is one of the Niger Delta river systems that contributes to the Rivers State fishresources. There has been unprecedented complaint from the fisherfolks on the dwindling finfish and shellfishpopulations; catches have been drastically reduced. Therefore, there is urgent need to study the finfishassemblage of this creek due to its location and the various human activities. A survey of the finfish catcheswas conducted to ascertain its assemblage. Finfishes collected from the landing centre of local fishers for 12months (April 2005 to May 2006) were identified according to standard method. These fishes were mostlycaught by non-selective cast nets of various mesh sizes by local fisherfolks during the low tide. Enumerationwas done by visual counting. A number was assigned to each fish species based on frequency of occurrenceor abundance (1-5). Analysis of variance and Duncan multiple range were used to analyse the data. A totalof 11 species from 8 families of finfishes dominated by Sardinella maderensis (47.33%) were observed.Seasonal catches of finfishes were not significant (p>0.05). The highest relative abundance was recorded inMarch (18.18%) and the lowest in April (9.09%). The low finfish species diversity indicates that finfishpopulation is over-fished by the local fishers and constant dredging activities have degraded the environment.Also it shows that nypa palms are not good nursery grounds for these fishes. It is therefore recommended thatthere should be closed fishing season, selective fishing gear should be used and dredging should be controlled.
Hydrocarbons pollution of soils has constituted environmental issues over the years. The biggest concern associated w ith hydrocarbon pollution in the environment is the risk to farmlands, fisheries and potable water supplies contamination. Several remediation techniques exist (Bioremediation and Non-bioremediation), which aim at reducing the hydrocarbon content of the polluted soil and water with their varying degrees of success. Thus land farming, one of the bioremediation remediation techniques is view ed as a more viable remediation options for hydrocarbon polluted soils. The study therefore was instituted to assess the effectiveness of land farming (Enhanced Natural Attenuation) in the remediation of hydrocarbon polluted sites in the Niger Delta. Soil samples from ten (10) sites polluted and remediated sites in the Niger Delta; that is five (5) samples each from the swampy and well drained sites and subjected to Laboratory analysis. The results were further analysed using both descriptive and inferential statistical tools of percentages, regression analysis and student t-test. The results of the soil analysis show 14.54 to 82.24% and 16.01 to 50.54% reductions in the TPH and PAH concentrations after land farming respectively. This shows high level of efficacy in the use of the Land farming as remediation technique. However, the efficacy varied between the swampy and well drained soils; reductions in the hydrocarbon levels of the soils in the water-logged or swamp areas were lower and slower than that of the well drained soils. This shows that the soil microbes were able to degrade the hydrocarbons faster in the well-drained soil probably because of the favourable soil conditions like pH, moisture, and nutrient. To ameliorate this problem, more effective way of bio-remediation for swamp area should be pursued like phyto-remediation; this is the use of higher plants to enhance the remediation of soils contaminated with recalcitrant organic compounds.
This paper presents the development of an e-assessment platform for application in Nigerianuniversities. Ahmadu Bello University, Zaria, Nigeria was used as a testing ground in 2008. In the age ofdigitalization that we live in, it has become imperative that a reliable means of assessing students using internetbasedtechnologies be developed. This paper seeks to solve a part of that problem by designing and developinga web application where tests in multiple choice formats will be taken online and graded immediately. The webapplication relies solely on Microsoft developed technologies. It runs on the Microsoft.net framework, uses theASP.NET web server, C# as the intermediate language, ADO.NET to interact with the relational database andMicrosoft SQL server as the relational database. The work was simulated in the Visual Studio Expressenvironment using Internet Explorer as the web browser. It was then tested on an intranet to ensure connectivityand could be relied upon for a w ide application to solve the problem of assessing the teeming population intertiary institutions.
The main purpose of this study was to investigate effective factors on the attitude of paddy growerstowards organic farming in Babol County in Iran. A sample size of 150 farmers was selected for this researchby using simple random sampling method. Result of regression analysis showed that participation in extensioncourses, access to extension communication channels and level of literacy and landholding were the effectivefactors on farmers' attitude toward organic farming that explained 42% of variance in the attitude index.
Field runoff estimation by the use of integrated circuit (ICL7106) digital converter is a new conceptof surface water flow measurement in the sub-Saharan Africa. It is a very efficient, low power analog to digital(A/D) converter. A runoff collector of area 1m2 and depth 30 cm was constructed, and a discharge pipe of 2.5cm diameter and length 60 cm connects the runoff collector to the runoff storage tank, 30 cm x 30 cm x 30 cmin dimension. Both the runoff collector and the storage tank were made of metal sheet (18 gauge). The activedevices used for the construction of the digital sensing device include decoders, display driver, referenceresistor, a clock, sensor, liquid crystal display (LCD) and lCL7106. The lCL7106 was designed to interface witha liquid crystal display (LCD), which includes a back-plane drive. This digital recording system was designedto measure the amount of runoff that flow into the runoff storage tank through the discharge pipe, such that theresistor sensed runoff according to the level of water in the tank. The sensor divides the reference voltage Vrin ratio to the value of resistance (R1). This varying voltage is now converted to digital readout by A/Dconverter with respect to liquid crystal display (LCD). The equipment was calibrated with the aid of standardmeasuring cylinder (1000 ml). It was observed that runoff within the range 7500 ml to 42000 ml could beadequately measured using the digital device. This research development is useful in weather forecasting, floodstudies and hydrological analysis in natural science studies.
In this study, a gear shifting mechanism was designed and applied to make the shifting process faster and less destructible for the driver. The new device must be reliable, has a small dimensions, low construction and maintenance cost. This paper aims to improve gear shifting process using devices as: a manual four speed gear box, four pneumatic double acting cylinders, four pneumatic two position five ways directional control valves, Programmable Logic Controller (PLC) LOGO unit, an electrical motor, an electrical clutch, a belt, two pulleys, limit switches, push buttons, bulbs, a table (holder) and power supply. According to suggested gear_ shifting method the driver can select the transmission gear ratio without moving his hands from the steering wheel by putting the gear shifting push buttons on the steering wheel. Using this method leaves to the driver the excitement of choosing the shifting moment.
An Obstruction Avoidance Generously Mobility (OAGM) model has been
introduced for controlling ad-hoc sensor networks and thereby operating
emerging fields like military and healthcare services. According to this
model, the ability to send a message to a group of users simultaneously,
based solely on their geographic location, is desirable by using Mission
Critical Mobility model that assumes the obstacle shapes like rectangle
or square in the simulation terrain. The OAGM model is developed by
grasping the critical situations of military and healthcare services by
incorporating the node movement model, hierarchical node organization,
placement of obstacle that affect the movement of nodes and also signal
propagation. Graph theory technique is used to find the shortest path of
the node movement process. The varying number of parameter sets with DSR
protocol is analyzed for MCM and OAGM mobility model. The results show
OAGM performance is better than MCM.
In this research the population for Muslim of Rural region in Bangladesh is predicted by using theexponential growth rate method. For this link, the information of data for the Rural M uslim population for maleand female of Bangladesh is obtained from 1991 and 2001 censuses. The predictions are computed in threephases. In the first phase, the predictions are computed using negative exponential growth model estimated bythe Quasi-Newton method using STATISTICA for the years 1991 and 2001. Using the Cross ValidationPredictive Power (CVPP) criterion and R2, the shrinkage coefficient (8) is constructed. The shrinkagecoefficient determines the adequacy of the first phase prediction. In the second phase, these predicted valuesare used to estimate the growth rate, for different age groups, by using the exponential growth rate m ethod. Inthe third phase, that is, finally considering the observed population for Muslim of Rural region in Bangladeshfor the Census year 2001 as the base population and using the estimated exponential growth rate, at differentage groups, of the second phase estimation, the predictions of the population of M uslim of Rural region areobtained for the years 2002 through to 2021 employing exponential growth rate method successively 20 times.
The solute transport owing to contaminant constituents in an emplaced solid waste was studied insaturated and oversaturated conditions using Sodium Chloride as the tracer. The flow was analysed usingphysical and probabilistic models commonly used in soil investigations. The Breakthrough Curves (BTCs)indicate relatively fast solute particles flowing vertically within the mass water flow in the w aste fill. Unlikein previous studies, the transport of solutes from the inlet to the outlet has been undertaken using a transfermodel, which is a function of volumetric water input. Although the simulated average fractional volume ofwater involved in the transport of solute particles appears to be slightly overestimated, the study indicates thatvirtually the entire water content of the saturated waste fill appears to be actively involved in solute transportwithin the waste mass. The disparity in the modelled and practicable values of the fractional flux in thesaturated waste fill indicates that some of the solute particles are irreversibly adsorbed within the waste mass.The study further indicates solute flow along the cell wall in the oversaturated condition, and in general, showsthe applicability of soil models to waste flows.
This study was to determine the concentrations of heavy metals (Cu, Zn, Co, Mn, Mg, Fe, Cr, Cd, As, Ni and Pb) in liver, kidney and meat of beef (cow), mutton (sheep), caprine (goat) and chicken, from Kasuwan Shanu Market in Maiduguri Metropolis, Borno State, Nigeria by using Perkin-Elmer Analyst 300 Atomic Absorption Spectroscopy (AAS). The levels of heavy m etals in the liver, kidney and meat of beef, mutton, caprine and chicken ranged from 0.23 to 1.22±0.21 μg/g Cr; 0.1 to 1.34±0.23 μg/g Pb; 0.10 to 1.44±0.06 μg/g Cu; 0.98 to 4.65±0.30:g/g Fe; 0.01 to 1.09±0.26 μg/g Ni; 0.45 to 4.11±0.44 μg/g Mn; 0.07 to 0.76±0.15 μg/g Cd; 0.01 to 0.34±0.23 μg/g As and 1.10 to 6.23±0.16 μg/g Zn. The concentrations of all the metals in the liver, kidney and meat of beef, mutton, caprine and chicken were found to be statistically significant (p<0.05). Generally, livers and kidneys w ere found to have the highest significant levels of metals and meat the lowest levels. When compared to one another (beef, mutton, caprine and chicken), there did show significant differences. Hence, the concentrations of all the metals were within the tolerance limits with the exception of Cr and Pb, which were higher than standard limits.
A new l-shaped mesogenic homologous series with polar bromo and nitro substituent wassynthesized by fixing rigid 2-bromo-4-nitrophenylazo groups to a resorcinol moiety. 4-n-alkoxybenzoyl groupsesterify both the phenolic -OH groups. In the present series, methoxy and ethoxy derivatives are nonmesogenic, n -propyloxy to n -octyloxy derivatives exhibit enantiotropic nematic mesophase. Smectic C (SmC)mesophase commences from the n - octyloxy derivative as an enantiotropic phase and is retained up to the lastmember synthesized. The effect of polar bromo and nitro substituent on mesomorphic properties is discussed.In this paper, we also report the unusual dielectric behaviour of n -octyloxy and n -tetradecyloxy derivatives ofthe present l-shaped mesogenic homologous series. The dielectric permittivity of the sample was found to beunusually low in SmC phase in comparison to nematic phase. We have explained it on the basis of twoconformermodel, which can exist in SmC phase due to specific shape of the molecule. The model has beensupported by calculating activation energy of both the possible conformers from Arrhenius plot of relaxationfrequency versus temperature. There is a clear difference in the value of activation energy of both theconformers as expected.
The pulse-width-modulation technique plays a very important role in the inverter gain control. New varied-pulse width techniques for power inverters of two schemes have been introduced in this study: Small Boundary-Pulse-W idth Technique (SBPW), and Large Boundary-Pulse-Width technique (LBPW). These techniques are developed to improve the inverter operation, based on minimum harmonic contents in the output voltage. The original pulse-w idth of an inverter operation is divided into multiple pulses of variable widths per half cycle. For the SBPW method a middle pulse and several boundary pulses per half cycle are deduced. The middle pulse is given the largest width and the boundary pulses are taken small widths. For LBPW method the opposite is considered. A software-model was developed by the authors to determine the conduction angles and their gating angles required for the inverter drive. The advantage of these techniques allow a modifying in the number of pulses per half cycle and their widths, leading to an inverter operation with less generation of harmonics. The SBPW technique makes the inverter output voltage closer to a sinusoidal form. Therefore, the optimal inverter performance is obtained with this technique.
Granite and marble saw ing powder wastes is w idespread by-product of industrial process in India.Generally these wastes pollute and damage the environment due to sawing and polishing processes. Graniteand marble wastes were collected from companies located in Salem district. Local clay and fired industrial brickmaterials were collected from Salem as well as nearby districts Namakkal and Erode, Tamilnadu, India. Firedindustrial brick was characterized by using FTIR and Mossbauer spectroscopic techniques. Mixtures wereprepared with 0, 10, 20, 30, 40 and 50 wt. % w astes incorporated into the raw clay material. For the briquettespecimens fired in between 500 and 900ºC, the technological properties such as compressive and flexuralstrengths, water absorption, porosity and bulk density are determined and the same properties have also beenobtained for industrial bricks. The results shows that granite and marble waste content upto 50 wt. % can beadded into clay materials of Salem, Namakkal and Erode in the production of bricks with no major determinaleffect on the properties of the sintered briquette specimens anticipating no costly modifications in the industrialproduction.
The world is fast becoming a global village and a necessary tool for this process is informationtechnology. Thus, this study examined the impact of information technology on the economies of small-scalebusiness enterprises, specifically on business growth and income flow, job creation, efficient businessmanagement and crime rate reduction. Survey approach was adopted and data was collected from 1000respondents randomly selected from some commercial communities in Nigeria; Lagos, Abuja, Benin, Ekpoma,Auchi, Ajaokuta and Okpella, using the questionnaire alongside personal interview. The Chi- Square (X2)statistic was used as an inferential tool. This was used to test the hypothesis formulated in the course of thestudy. Findings generally indicate that information technology has impact on small-scale business enterprisesin terms of business growth and income flow, job creation, efficient business management and drastic reductionof fraudulent activities in business. Thus, it w as concluded that the benefits of information technology to smallscalebusiness enterprises cannot be overemphasized. However, information technology resources are stillunderutilized in the rural areas. Hence, focus should be shifted to optimum utilization of information technologyresources for the benefits of all small-scale business enterprises in Nigeria.
This study aim at developing low cost underwater navigation system suitable for shallow water environment. Spectral Plus 5.0 software running on two computers was used for generating and measuring sound pressure in open air and shallow water (350 mm deep) using a pair of piezocrystals plates (2 cm diameter) from old wristwatch buzzer. The best frequency response was found to be at 4.5 kHz without amplification. The setup was able to respond to obstacles placed in between them when spaced at experimental distance of 30 cm and 60 cm. Obstacles used are plywood, asbestos, PVC plastic and Iron sheet. It was found that the responses are material dependent.
A major drawback of directional and horizontal well drilling is the numerous complex computations required to be done while planning a well. These computations are very stressful and time consuming especially when done manually. One of the objectives of this study was to develop a user friendly Excel Spreadsheet program that would make the computations of these well trajectory parameters easier, faster and accurate. An Excel Spreadsheet program was developed employing the Minimum Curvature method (and for other five methods) for wellpath design and planning. This would help increase the usage of these trajectory methods especially the Minimum Curvature method. The program is able to provide pictorial views both in the vertical and horizontal plane of the trajectory of the drilling bit’s position in the wellbore. This w ould therefore help to minimize risk and uncertainty surrounding hitting predetermined target. This is possible because deviations can easily be detected and the necessary directional corrections or adjustment be initiated to re-orient the drilling bit to the right course before (planning process) and during the drilling operations.
Energy is a fundamental ingredient in the process of economic development, as it provides essential services that maintain economic activity and the quality of human life but intensive use of it causes problems threatening public health and environment. The aim of this study was to evaluate energy consumption and greenhouse gases emission from canned fish production in the Khuzestan province, Iran, to determine the losing energy factors and pollutant emission. In this research, canneries, consuming human labor, electricity and diesel fuel energy sources w ere investigated. Total input energy was 22681.8 MJ/t that diesel fuel had the biggest share in the total energy up to 98%. Energy of labour was a small amount of total input energy, but it is the most expensive input in the canned fish production. Primary cooking and sterilization operations are most consumers of input energy in canning fish production with 21202.6 MJ/t. Manual operations of fish cleaning and transferring, includes the lowest energy and this stage includes 43.33% of total human labour. Amount of greenhouse gas and air pollutant emissions from diesel fuel is much greater than electricity in fish cannery. Emission of CO2, NOX and SO2 are the most gas emission with 1071.282, 7.264 and 6.52 Kg/t, respectively. Productivity of labour and electricity, diesel fuel and labour energy were 0.025 t/La 1h and 2.2, 0.044 t/GJ and 0.056 t/MJ, respectively. Using agitating retorts in steed of still retorts and reform path of transferring vapor will decrease the diesel fuel consumption and greenhouse gas emission.
The purpose of this research was to examine the flank wear and surface roughness in turning gray cast iron using cryogenically treated carbide inserts. Turning experiments were conducted with cutting velocities: 53, 85, 99, 149 m/sec, feeds: 0.12, 0.16, 0.2, 0.24 mm/rev and a constant depth of cut: 1.5 mm. The specimens were turned using cryogenically treated and non-treated carbide inserts. The cryogenic treatment cycle consisted of cooling the test samples from room temperature to cryogenic temperature of -178.9 C in 3 h, soaking at cryogenic tem perature around 24 h and warming to room temperature in about 5 h. The surface roughness (Ra, R z, Rq and Rt :m) of the turned specimens was measured using talysurf and flank wear of the tool was measured using toolm akers microscope. The experimental layout was designed based on the Taguchi’s Orthogonal Array technique and ANOVA was performed to identify the effect of the parameters on the response variables. Cryogenically treated inserts proved superior to the non-treated in all the test conditions in terms of lesser flank wear of the inserts and reduced surface roughness of the specimens. The after turned inserts w ere examined using Scanning Electron Microscopy for studying the flank wear mechanism.
Radiotracer Residence Time Distribution (RTD ) method was used to investigate the process of clinker grinding in Ghana Cement Plant (GHACEM) at Tema with the objective of determining hold-up and grinding efficiencies of two ball mills operating in close circuit regime. The experiment was conducted using 40Ci Au-198 radiotracer in liquid state and highly sensitive NaI detectors for radiation measurement. The experimental RTD data revealed that the Mean Residence Times (MRT) of the material in the milling and separator sections of both mills were the same. It was also observed from the estimated mill efficiencies that mill 4 operated with optimal performance while the efficiency of mill 3 was far below the expected value.
The aim of this study to characterization and the kinetics of degradation of the oil during heating on the seed and Sesame oil (Sesamum indicum L.). The results showed that the seed contained 5.7% moisture, 20% crude protein, 3.7% ash, 3.2% crude fiber, 54% fat and 13.4% carbohydrate. The seeds were found to be good sources of minerals. Potassium (851.35±3.44 mg/100g) was the highest, followed in descending order by Phosphorus (647.25±3.52 mg/100g), Magnesium (579.53±0.42 mg/100g), Calcium (415.38±3.14 mg/100g) and Sodium (122.50±4.21 mg/100g). The physical properties of the oil extracts show ed the state to be liquid at room temperature. The oil was found to contain high levels of unsaturated fatty acids, especially oleic (up to 38.84%) and linoleic (up to 46.26% ). Sesamum indicum L. oil can be classified in the oleic-linoleic acid group. The degradation kinetic of the oil was also investigated. The thermal oxidation of the double bonds of the oil showed a first-order thermal oxidation kinetic and the Arrhenius plot yielded a straight line with a slope equivalent to activation energy of 12.428 KJ.mol-1.There is the possibility of considering the seed as feed supplement and its oil for industrial application.