203 research outputs found
Availability of Silica in Dusts at different operations locations in Limestone Quarry in Ewekoro, Nigeria
No full textThe dusts from mines and quarries have been reported to induce respiratory problems among mineral workers. This study was carried out to investigate the availability of free silica in the dust from different parts of the quarry with different activities. The blasted, boreholes and stacked sites were investigated. The collected dust was analyzed using an X-Ray analyzer. The result shows that the highest free silica content (mean of 22.279%) was found in dusts from borehole, followed by blasted parts (17.195%). The stacked shows the least mean (7.566%). The statistical analysis carried out on the result using SPSS software shows that there is statistical independence of the dust from different sections of the quarry, meanwhile the values of the means are environmentally significant. The recommendations were made on how to control the negative effect of the free silica in every aspect of the quarry with emphasis on borehole drilling section
Solid Verifiable Credentials
No full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 63-66).Credentials are an integral part of our lives, as they express our capabilities and enable access to restricted services and benefits. In the early 2010s, the Verifiable Claims Working Group of the World Wide Web Consortium (W3C) proposed a specification for what is now the Verifiable Credentials Data Model. This living specification, which is still in development, outlines a cogent framework for the issuance, storage, presentation, and verification of credentials on the Web. Many of the leading Verifiable Credentials projects leverage Distributed Ledger Technology (DLT), potentially compromising Web interoperability and sometimes exposing otherwise personal data. SolidVC is a decentralized Verifiable Credentials platform built with the open protocols of the Web. It is implemented on top of Solid, a Web framework developed at MIT in 2016 that allows decentralized applications to interact with personal user data to provide services in an access controlled environment.by Kayode Yadilichi Ezike.M. Eng.M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Scienc
Petrophysical Characterization Of Reservoir And Oil Properties As A Tool For Choosing Optimal Enhanced Oil Recovery Methods: Case Study Of Dawson Bay Formation, Divide County, North Dakota, United States
No full textIn unconventional reservoirs, i.e., shaly or tight sand formations, with low porosity and very low permeability, the oil recovery factor is low hence enhanced oil recovery is important. In the conventional reservoirs, once the primary and secondary stages of recovery are exhausted, about two-thirds of the original oil in place is left behind. Enhanced Oil Recovery aims to recover the remaining oil (Green and Wilhite, 1998). These makes the enhanced oil recovery to be of great importance. Efforts are always in place to see how the system can be improved.
The study was carried out to describe the overview of rock types, depositional environment and diagenetic history of the Dawson Bay Formation, and overview of structural geology of the Dolphin Field by studying the Well logs and Cores from the drilled wells, thin sections and using computer softwares i.e. Neuralog, Petra, Surfer. The petrophysical properties of the formation in the field i.e., rock type, porosity, average permeability, oil saturation, production depth, net thickness, temperature and Oil properties, i.e., API gravity, viscosity, oil composition were determined in the laboratory by experiments including Nuclear Magnetic Resonance (NMR) and careful observations of the well logs, and well logs processing using Neuralog, Petra and Artificial Neural network of Matlab. The validity of Screening Criteria by Taber et al. (1997) which recommends Enhanced Oil Recovery Method(s) for formations based on the petrophysical properties for Dawson Bay Formation in Divide County, North Dakota and the optimal method of Enhanced Oil Recovery for the Dawson Bay Formation in Divide County, North Dakota which has its own distinct petrophysical properties and oil properties at laboratory scale at laboratory scale was investigated by conducting Surfactant and brine concentrations spontaneous imbibition experiments, Carbon Dioxide flooding tests, and Carbon Dioxide ‘Huff n Puff’ simulation tests using Computer Modelling Group (CMG) STARS software.
The result of the study shows that the reservoir rock, predominantly dolomite, slightly limestone, thickens from about 10 ft to about 100 ft. It’s thick at the mid-eastern part of the field and thins sideways. This may likely suggest the topography of the marine environment where the limestone was deposited before it was characterized by diagenesis for hydrocarbon accumulation. The oil producing wells are on Nesson Anticline, the reservoir trap has a structural element. Since no clear closure was seen on the structure of the field, reservoir trap may be attributed to halite plugs in the dolomite rock, making it more stratigraphic than structural. The values of the petrophysical properties of the formation obtained from log analysis deviate from values from core analysis. The correlation value was also too low for a reliable relationship. The correlational coefficient for depth 9917 to 9932 ft with 0.5 ft incremental for Well 12071 is about -0.1932, which shows a poor relationship. Artificial Neutral Network (ANN) was used to establish the relationship which can be used to predict the actual petrophysical properties of the formation in other wells. The EOR screening method from Taber et al. (1997) is to a good extent applicable to the Dawson Bay Formation, Dolphin Field. Surfactant flooding and CO2-EOR methods are applicable to the formation based on experimental results and CO2 numerical simulation. The brine, surfactant and CO2 flooding will improve oil recovery from the formation though in varying degrees. The surfactant gave the highest yield of all from experimental results. The prevailing economics, cost of surface and injection plants, environmental among other considerations will influence the method to be used eventually at a time of execution of EOR operation
DETERMINANTS OF INFLATION IN NIGERIA: A CO- INTEGRATION APPROACH
No full textInflation is undeniable one of most leading and dynamics macroeconomics issues confronting almost all economies of the world. Its dynamism has made it an imperative issue to be considered. Hence the study examines the factors affecting inflation in Nigeria. Time series data were employed for the study. The data was sourced from the Central Bank of Nigeria and National Bureau of Statistics. Descriptive statistics and cointegration analysis were the analytical tools used. It was observed that there were variations in the trend pattern of inflation rate. Some of the variables considered were significant in determining inflation in Nigeria. The previous total export was found to have a negative impact on current inflation while the previous total import exerts a positive effect likewise the food price index. It has thus been recommended that policies that will set the interest rate to a level at which it will encourage investment and increase in production level could be institutionalized, importation should be reduced in Nigeria such that it will not encourage change of consumer taste resulting to inflating prices, exchange rate system should be maintained at a level that will not impose threat on the Nigeria economy and the domestic consumption of petroleum product should be focused, not only exportation.Financial Economics,
Stroke pattern and outcome of management in type 2 diabetics in a tertiary hospital in North Western Nigeria
No full textBackground: Diabetes mellitus is a well-recognized risk factor for stroke. Clinical features, as well as outcome of stroke, difference between diabetic and nondiabetic patients. The objective of this study is to determine the pattern and outcome of management in diabetes-stroke co-morbidity. Materials and Methods: This is a retrospective study where case folders of patient admitted from January 1 to December 31, 2009 with the clinical diagnosis of stroke were traced. A questionnaire was used to extract relevant data from case folders. Results: A total of 115 patients with the clinical diagnosis of stroke were admitted during the study period, but only 88 had complete information out of which 12 (13.6%) had type 2 diabetes. The mean age of the diabetic group (69.67 ± 12.7 years) was found to be significantly higher than that of the nondiabetic group (56.93 ± 16.06 years) (t = 2.615, P = 0.011). Ischemic stroke occurred more frequently in the diabetes stroke the co-morbid group. However, the difference was not statistically significant (χ2 =0.079, P = 0.540). Outcome in terms of neurological recovery tended to be poor in the diabetes-stroke co-morbid group as compared to the nondiabetes stroke group (χ2 =13.93, P = 0.006). Conclusion: Stroke pattern and outcomes are different in the diabetic patient compared to nondiabetic patient. There is more prevalence of ischemic stroke in the diabetic group of patients often with slow recovery
Effect of the rock dimension on surfactant imbibition rate in the Middle Member of Bakken: Creating a model for frac design
No full textSome Robust Ridge Regression for handling Multicollinearity and Outlier
No full textRidge Regression and Robust Regression Estimators were proposed to deal with the problem of multicollinearity and outlier in a classical linear regression model respectively. This paper proposes a robust ridge regression estimator (RRR) for solving the problem of multicollinearity and outlier in a classical linear regression model simultaneously
Empirical Analysis of Agricultural Growth and Unemployment in Nigeria
No full textUnemployment which has been identified as the major cause of poverty is a worldwide economic problem. Poverty alleviation has been a great concern to developing countries. The economic burden of unemployment on a society necessitates this study. Consequently, this study analyses the Nigerian agricultural growth rate, its contributions, and examines the linkage and dimension of agricultural growth and unemployment rates. Collected time series data were analyzed with the aid of t – test, Duncan Multiple Range test, Granger Causality test and regression analysis. Results showed that Nigerian agricultural growth rate has an inverse relationship with unemployment and re – establish the Cobweb supply theory. In addition, increase in agricultural growth decrease unemployment and thus can alleviate poverty. Consequently, recommending polices to alleviate poverty should focus on increasing agricultural growth.Cobweb supply theory, Granger Causality test, Nigeria, Unemployment, Agricultural and Food Policy, Community/Rural/Urban Development, Environmental Economics and Policy, Farm Management, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, International Relations/Trade, Marketing, Productivity Analysis, Research and Development/Tech Change/Emerging Technologies,
Novice teachers: the challenges, supports, and effective strategies
No full textThis study used survey research to investigate the challenges novice teachers experience, the support they receive, and the leadership strategies that are implemented to support them. The research was conducted in Manitoba, Canada. Quantitative methods and convenience sampling were used to explore the research questions that guided this study: What challenges do beginning teachers perceive they encounter in their first years of teaching practice? What supports do new teachers report they receive? What strategies do novice teachers perceive are the most effective in supporting them? What challenges do school principals perceive novice teachers face? What strategies do principals use to support novice teachers? A total of 41 novice teachers and 31 school principals in Manitoba, participated in this study. The majority of the novice teacher participants were female and the majority of principal respondents were male – statistics which reflect the gender demographics of teachers and principals in Canada. The areas that novice teacher participants found most challenging were differentiating instruction, planning and preparation, accessing teaching resources, working with students with Individual Education Plans (IEPs), and assessing student learning. With regard to gender, male novice teachers found differentiating instruction and organizing the classroom significantly more challenging than did their female colleagues. Beginning teachers in rural/small town areas perceived isolation and teaching multi-age classrooms to be a greater challenge than their colleagues who taught in urban/suburban schools. With regard to teaching experience, teachers with less than two years in the classroom perceived isolation to be a significantly greater challenge than colleagues with 2-3 years teaching experience. When considering school size, teachers in smaller schools with less than 200 students considered isolation to be a greater challenge than their colleagues in larger schools; however, teachers in larger schools found planning and preparation and developing collegial relations a greater challenge than those in small schools. With regard to the areas in which novice teachers reported they received most support, the areas most supported corresponded with the areas they felt to be the greatest challenges, with the exception of differentiated instruction, which was their greatest challenge, yet was not well supported. Overall, female novice teachers perceived higher levels of support than their male colleagues. Teachers in rural/small town areas felt more supported than colleagues in urban/suburban locations. Novice teachers valued support programs such as mentoring, induction, and professional development but indicated that not all these programs were available to them. Principals identified similar challenges for novice teachers as did the teacher respondents, with the exception of planning and preparation, an area that challenged beginning teachers but was perceived as less of a challenge by their principals. Principals reported greater availability of mentoring programs than did novice teachers. The recommendations for the study included specific areas for professional development and greater provision of research-based mentoring and induction programs.Includes bibliographical references (pages 110-121)."In partial fulfillment of the requirements for the degree of Master of Education.
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