Archives-December 

An extensive review conducted before this study, showed data limitation is the main constrain for multiple regression approach. Thus, new technique has been innovated through bit wear distribution over drilled interval depends on formation fingerprint. Field geological, drilling and logging data collected from three wells located in Blue Nile basin subjected to considerable concentrated analysis. Drilling rate predicted as a function of optimum weight on bit and rotation per minute using Bourgoyne and Young model. The Unknown Bourgoyne and Young coefficients have been determined. Correlations of multiple regressions using Statistica-12.5 software predict acceptable values of nine unknown coefficients. Hypothesis test of predicted coefficients showed over 95% confidence interval which simulated saving in time of drilling by 25%. Out comes was verified through Payzone drilling simulator via simulating actual field observations and re-simulate predicted ROP values. Results revealed the proficiency of predicted drilling rate values. The rate of penetration general equation constructed for each formation; then graphs produced for each formation individually depends on bit type and operational conditions.The methodology and out comes presented in this paper enable prediction of optimum penetration rates directly through accurately produced graphs that is during the well planning period for next wells to be drilled in Blue Nile Basin or other similar formations. This research offers new technique via distribution of drill bits dullness over drilled interval to overcome data limitation constrain. Together with qualitative and quantitative analysis of the optimized results that revealed high potentiality of new technique through both operation and economic benefits on drilling.

The phase change process for energy storage is a complex heat transfer phenomenon and the solidification and melting process make the charging and discharging process entirely a transient heat transfer process. Analytical solutions are not available to evaluate the temperature of the PCM during the charging and discharging process. Hence, numerical methods are to be adopted to solve the governing equations involved during this transient heat transfer phenomenon. Further, the correlations are developed using the results obtained from the regression analysis using the experimental results to provide simple solutions to the practicing engineers. In this study, heat transfer experiments were conducted under different levels of air flow rate, inlet temperature, charging and discharging time according to the central composite rotatable design matrix. Within the design space, heat transfer variables were optimized using response surface methodology (RSM) concept to the required PCM melting temperature and room temperature. Further, optimized results show that the minimum PCM melting temperature of 29.8 ºC and room temperature of 28.6 ºC are obtained at the mass flow rate of 0.06 kg/s, inlet temperature of 31.4 ºC, and discharging time 86 mins by optimizing process parameters.

The fiber reinforced laminate composite plates, because of its outstanding mechanical properties such as high strength, high stiffness with less weight, durability, corrosion resistance, finds many engineering applications. In this work, local failure of plate alone in-between the stiffeners is taken for study. This work compares the buckling behavior of thin fiber reinforced laminate composite plates subjected to axial compression under different types of boundary conditions with different types and different angle of layups. For this purpose graphite / epoxy composite rectangular plate is used for the analysis. Further, by varying the dimension of plate, effect of the aspect ratio of the plate on the buckling strength of plate is also studied. Eigen buckling analysis of ANSYS is used for analysis.

Every year thousands of students leave the regular formal educational institutions in Kenya, but they cannot progress to higher levels of formal education. Despite past investments in Kenya’s Technical, Industrial, Vocational Education and Training (TIVET) subsector, many school leavers fail to access TIVET. This is because the subsector is said to be facing many challenges related to wastage of resources, irrelevant training and turnover of personnel. Performance contracting has been acclaimed as an effective and promising means of improving the performance of public enterprises as well as government departments. The government of Kenya introduced performance contract signing in the year 2004. The performance contracts were aimed at improving resource utilization in public institutions among other objectives. This study sought to establish the perceptions of Kenyan tutors in Technical Institutes in Rift Valley about the impact of performance contracts as a paradigm shift on the utilization of teaching and learning resources. The study adopted a survey strategy. The study population comprised of tutors, Heads of Department and Principals of randomly selected public Technical Institutes in Kenya. The stratified random sampling technique was applied in the selection of the study sample. This involved the grouping of tutors into 8 strata according to the available departments. Thereafter the proportionate random sampling technique was applied to get an equal proportion of respondents from each stratum. The saturated sampling technique was used to sample the heads of department and principals. Questionnaires and interviews were used to collect data. This entailed the supplying of questionnaires to tutors, heads of department and principals of the sampled Technical Institutes. Interviews were conducted with principals of the sampled institutions.

The physico-chemical characteristics of Otamiri River were investigated using digital meters and Atomic Absorption Spectrometer (AAS). The aim of the study was to provide information that will be useful in the sustainable development of the River. The results indicates that the mean pH concentrations of the Otamiri river obtained at four strategic gauge stations designated SSWS1 - Egbu, SSWS2 –Timber Market, SSWS3 – FUTO and Downstream-Mbirichi were 6.45, 6.58, 6.45 and 6.50 respectively for the mean pH while the mean values for Pb2+ were 0.02, 0.02, 1.67 and 0.02 mg/l respectively, that of Cd2+ was 0.004, 0.0036, 0.004 and 0.002 mg/l respectively while the mean concentrations for Fe+ were 0.01, 0.016, 0.23 and 0.10 mg/l. The result of stream sediment samples indicates that the concentrations of pH were 5.8, 5.90, 6.30 and 4.45 respectively while mean concentrations values for Pb2+ were 0.08, 0.07, 0.06 and 0.05 mg/kg respectively while the values for Cd2+ were 0.32, 0.28, 0.30 and 0.25 mg/kg respectively. The values for Hg were 0.10, 0.13, 0.15 and 0.18 mg/kg. The results for both water and sediment samples with respect to pH and some heavy metal concentrations were not in conformity with World Health Organisation (2011) standard for safe drinking water as well as Federal Ministry of Environment (2006) standard for soil respectively thus, constitute a threat to the River; these are attributed to waste dumps and anthropogenic activities around the four stations The Sodium Adsorption Ratio (SAR) of the river indicates that it is excellent for irrigation purposes even though correction of the pH needed to be done. The pollution index (PI) of the river shows that it is tending towards its critical value of 1. The pH of the water can be treated using sodium bicarbonate while the sediment by liming method while the excessive concentrations of heavy metals can be treated using acornic acid.

Dermatofibrosarcoma protuberans (DFSP) is a relatively rare skin tumor that is considered to have intermediate malignancy; it demonstrates frequent local recurrence, but systemic metastasis is rare [1]. A 38 year old male presented with multiple cutaneous nodular lesions of DFSP since 6 months, who underwent for CT scan that revealed distant metastasis to: the pleura, pancreas and psoas muscle.

The aim of this study is to evaluate the potential toxic effects of mancozeb on stress biomarkers such as catalase (CAT) activity, malondialdehyde (MDA) level and protein level in the brain tissue of zebrafish (Danio rerio). Mancozeb, is a synthetic fungicide contaminating aquatic environments as a potential toxic pollutants, was investigated in the present study for acute toxicity. Zebrafish groups were exposed to different doses of mancozeb (5 mg L-1 and 7,5 mg L-1) for 120 hours. Catalase (CAT) activity, Malondialdehyde (MDA) level and total protein level were determined with spectrophotometer. The results showed that CAT activity and MDA level decreased in all experiment groups. Protein level increased in the experiment groups when compared to the control group. In conclusion, the changes in the CAT activity and MDA levels were time and as well as mancozeb dose-dependent. Furthermore, the biochemical parameters of mancozeb exposure on zebrafish, showed that mancozeb has significant effect on the zebrafish and/or aquatic organisms.

Tunnels represent a key part of the world transportation system playing a fundamental role both in people and freight transportation, especially in developed countries. Around the world, most major cities and metropolitan areas have metro systems accounting for hundreds of kilometers of underground tunnels and network systems. This study presents the pressure losses in ventilation systems of a long circular tunnel using for a metro purpose length of 700m, and diameter 6.6m, K.M.R.C., Kolkata has been vividly studied and presented in this dissertation. The tunnel which is being driven in the soft soil by using a tunnel boring machine has already developed up to a length of 700m and till the excavation is going on to continue. Auxiliary ventilation is adopted to ventilate the tunnel with the help of an axial-flow fan connected to a duct of approximately 680m in length. The various ventilation related parameters, viz. air quantity, pressure and temperature of the air in various locations inside the tunnel have been studied. In addition, we emphasize the pressure losses in tunnels in various locations i.e., to consider as bend taking place has been calculated. In the Kolkata metro, there is an earth pressure balance TBM is used. EPB excavation provides continuous support to the tunnel face by balancing the earth pressure against the forward pressure of the machine, and the advancement rate is 15 meters every day. In addition, the pressure losses in various tunnel configurations have been computed from the empirical relations as well as computational fluid dynamics (CFD) simulations. The aim of this project work is to correlate the values of pressure losses of analytical results and the computational simulation results with the help of using CFD software and conclude the difference of graph plotted to assess the adequacy of the tunnel and suggest a few measures to improve the ventilation inside the tunnel for building a cordial environment and enhancing the tunneling operation. This study suggests that pressure losses in field study and CFD simulation are approximately the same.

The main objective of the present study is to predict the ultimate strength of PVC-concrete composite columns (a new type of composite columns consisting of a PVC tube filled with concrete). The study aimed at to investigate the potential of using fuzzy inference system (FIS) to predict the strength of the composite columns. Two models, Mamdani and Sugeno FIS model, having three inputs, one output, and twenty linguistic rules were constructed. The models were trained with input and output data. Using only the input data in trained models, the ultimate strengths values of PVC-concrete composite columns were found. According to the coefficients of correlations, both models have high prediction performance. The obtained values ewre very close to the experimental results. The average values of ratios of experimental to predicted ultimate loads were 0.994 and 0.999 for the Mamdani and Sugeno FIS model, respectively. Fuzzy inference system (FIS) model has been proved to be very effective in predicting the ultimate strength of PVC-concrete composite columns without attempting any experiments in a quite short period of time with tiny error rates.

A graph with n vetices is said to have a prime labeling if the vertices can be labeled with first n positive integers such that each pair of adjacent vertices are relatively prime. The present work in prime labeling focuses on finite simple undirected graphs, in particular on complete bipartite graphs. Our results are analogous to those stated by A. H. Berlineer et al., where they considered prime and coprime labeling of complete bipartite graphs while ours are for prime labeling of complete tripartite graphs. In our work, we have proved prime labeling for the general case K_(1,m,n), where m,n are positive integers. Further, some non-existing cases have been proved.