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Search Results: 1 - 10 of 53179 matches for " Ademola David;Oyawale "
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Mixture experiments and their applications in welding flux design
Adeyeye, Ademola David;Oyawale, Festus A.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2008, DOI: 10.1590/S1678-58782008000400008
Abstract: the traditional welding flux development has been by cost, material, time and labour intensive experiments. the extensive and expensive trial and error experimentation is needed because it is often difficult to know a priori how the flux ingredients interact to determine the operational characteristics of the flux and the final performance of the welded structure. the limitation of the traditional approach includes: (1) long lead-time (2) expensive experiments in terms of materials and energy consumption and labour requirements (3) the flux developed can not be guaranteed to be optimal and (4) inability to identify and quantify direct and interaction effects of flux ingredients. these constraints are due to the paucity of statistical modelling tools in welding flux technology. since prediction models are derived from designed experiments, flux researchers need other methods by which flux experiments may be designed. this paper discusses a statistical modelling tool known as mixture experiment which has the potential to revolutionize welding flux development technology. mixture design is discussed but not fully developed. the procedure of mixture experiment, analytical model forms and the sequence of model fitting are discussed. areas of welding flux research where the various mixture designs may be useful are suggested.
Weld-metal property optimization from flux ingredients through mixture experiments and mathematical programming approach
Adeyeye, Ademola David;Oyawale, Festus Adekunle;
Materials Research , 2009, DOI: 10.1590/S1516-14392009000300015
Abstract: this paper presents a new methodology for weld-metal properties optimization from welding flux ingredients. the methodology integrates statistical design of mixture experiment with mathematical programming optimization technique. the mixture experiment is responsible for the modeling of the weld-metal properties as a function of welding flux levels while mathematical programming optimizes the model. data and confirmed models from the literature were used to perform optimization on the responses. the maximum values possible with the prevailing conditions for acicular ferrite, charpy impact toughness and silicon transfer are 51.2%, 29 j and 0.231% respectively while the minimum oxygen content possible is 249 ppm. the new methodology is able to eliminate the limitations associated with the traditional experimental optimization methodology for flux formulation.
Simulating Land Cover Changes and Their Impacts on Land Surface Temperature in Onitsha, South East Nigeria  [PDF]
Ademola Akinbobola
Atmospheric and Climate Sciences (ACS) , 2019, DOI: 10.4236/acs.2019.92017
Abstract: The increasing urbanization generally is brought about by many eco-environmental problems, such as the drastic change of land use and development of urban heat island. This study identified the pattern of land cover changes in Onitsha, South East Nigeria, and assessed the trend in temperature over the area from 1986 to 2016, simulated the land cover changes for 2030 and 2044, and estimated their impacts on land surface temperature (LST). These were with the view to determining the effects of changes in land use/cover on the LST in the area. Primary and secondary data were used for the study. The primary data were coordinates of geographic features within the study area, collected through the use of global positioning system. The secondary data were minimum and maximum temperature data from the Nigerian Meteorological Agency (NIMET), high-resolution Quick-bird imagery, Landsat TM/ETM imageries for four epochs (1986, 2002, and 2016) with path and row of 189 and 56. Individual components (bare surface, built-up, vegetation and surface water bodies) in the study area were extracted from the images. Radiometric correction was first performed (for 2016 landsat imagery) to fill the line scan corrector (LSC) gaps using Focal Analysis tool in ERDAS Imagine 14.0. This was followed with clipping of the satellite imagery to extract only those portions that are within the boundary of the study area. Supervised image classification was done for the three series of remotely sensed imageries to extract the spatial pattern of land cover change. The results revealed that the study area has been growing to a relatively compact urban agglomeration. The concentration of built-up area at the western and the central part of the study area has been getting larger and more aggregated. Built-up area increased by 11.49% from 1986 to 2002 and 5.68% from 2002 to 2016 while vegetation decreased by 6.03% from 50.26% in 1986 to 44.23% in 2002. The decrease further continued from 44.23% in 2002 to 29.79% in 2016 (change of 14.44%). Expansion to spread into the sub-urban and rural communities bounding the metropolis, converting agricultural and green area to built-up areas. The land cover trend of the study area from the period of 1986-2016 shows dramatic changes for the dominant land cover types. The analyzed trend in temperature change shows that the central parts of the city have a temperature higher than the outlying parts. The results indicated that the average temperature of the study area increased from 24
Luminescence Characteristics of Feldspar from Nigeria  [PDF]
Janet A. Ademola
Natural Science (NS) , 2014, DOI: 10.4236/ns.2014.612094
Abstract:

The luminescence characteristics of feldspar from Nigeria were investigated. Without preheat treatment, the TL glow curve exhibited two peaks at 136°C and 175°C. When preheated to a temperature of 200°C only one peak was observed at 240°C. The highest net IRSL intensity was obtained for a stimulation temperature of 250°C. The TL signal is reduced by IR stimulation, and the longer the stimulation the more pronounced the effect. The dose response curves for both the TL and the IRSL showed a linear relationship for the doses considered in the study. Dose recovery test performed using the SAR method showed consistency with given dose for both TL and IRSL.

Estimation of Annual Effective Dose Due to Ingestion of Natural Radionuclides in Cattle in Tin Mining Area of Jos Plateau, Nigeria  [PDF]
Janet Ayobami Ademola
Natural Science (NS) , 2014, DOI: 10.4236/ns.2014.65029
Abstract:

Contamination of land could occur during the extraction and handling of materials containing high levels of naturally occurring radionuclide materials. These radionuclides find their ways into the food chain. The activity concentrations of natural radionuclides 40K, 226Ra, and 232Th in heart, liver, kidney, lungs, spleen and beef of cattle slaughtered and consumed in a tin mining area of Jos Plateau, Nigeria were determined by gamma ray spectroscopy method. The activity concentration of 40K is the highest in all the samples. The annual effective dose to man through the ingestion of the radionuclides in the organs was estimated. The mean annual effective doses calculated are 35.35 ± 13.84, 57.89 ± 38.27 and 46.93 ± 10.28 μSv?y?1 for heart, liver and kidney, respectively. Those of lungs, spleen and meat are 28.44 ± 15.70, 48.34 ± 28.85 and 41.24 ± 3.56 μSv?y?1, respectively. These are of the order of two magnitudes higher than those obtained for food in Abeokuta, Nigeria.

A New Eighth Order Implicit Block Algorithms for the Direct Solution of Second Order Ordinary Differential Equations  [PDF]
Ademola M. Badmus
American Journal of Computational Mathematics (AJCM) , 2014, DOI: 10.4236/ajcm.2014.44032
Abstract: This paper focuses on derivation of a uniform order 8 implicit block method for the direct solution of general second order differential equations through continuous coefficients of Linear Multi-step Method (LMM). The continuous formulation and its first derivatives were evaluated at some selected grid and off grid points to obtain our proposed method. The superiority of the method over the existing methods is established numerically.
Giant Ascending Aortic Aneurysm: Are There Peculiarities in the Developing World?  [PDF]
Ademola J. Adekanmi, Doyin Olusunmade
Open Journal of Clinical Diagnostics (OJCD) , 2014, DOI: 10.4236/ojcd.2014.42017
Abstract:

Aim: To highlight the imaging features and the peculiarities associated with a giant ascending aortic aneurysm in a typical developing world setting. Presentation of Case: A 78-year-old known hypertensive and asthmatic woman of 25 and 10 years duration respectively. She had an untreated degenerative aortic valve lesion and moderate aortic regurgitation. This case study showed the complex interplay of background untreated aortic valve disease, aortic insufficiency, chronic hypertension, chronic airway obstructive disease and ageing in a case of giant aneurysm of the entire ascending aorta. It also emphasizes the role of imaging in diagnosis and follows up of ascending aortic aneurysm particularly where prevention is key to prevent the high mortality associated with Thoracic aneurysymal rupture. Conclusion: Timely institution of appropriate treatment of aortic valve disease, prevention and adequate control of hypertension is key to prevent the development and the grave prognosis of ascending aortic aneurysm, particularly in the developing world where appropriate medical facilities, expertise and treatment are scarce.

Local Government and Good Governance in Nigeira’s Emerging Democracy, 1999-2011: An Analysis of the Constraining Factors
Ademola Adebisi
Canadian Social Science , 2012, DOI: 10.3968/j.css.1923669720120806.2666
Abstract: When local governments were democratically instituted in Nigeria in 1999, Nigerians widely assumed that democratic rule would usher in good governance at all levels. This study however discovered that the expectations of the people have not been largely met. This failure the study further discovered is attributable to a number of constraining factors. The paper analyzed these constraining factors and prescribed measures that can engender good governance at the local level in the country
Evaluation of safety practices and performance in a brewery industry in Nigeria between 2000 – 2007
FA Oyawale, AO Odior, RO Bolanle
Journal of Applied Sciences and Environmental Management , 2010,
Abstract: Safety practices and performance in a brewery industry in Nigeria was evaluated for a period of eight years between 2000 – 2007 using the principles of statistical expectation and efficiency index. The number of prevented accidents and the corresponding values of lives and property saved were estimated annually for the same period of eight years. The type of input resource, total number of input resources, total number of prevented accidents by class, the unit cost of each of the accident class, the cost of input resources, quantity of each type of input resources and the targeted period were identified. The study revealed that a total of 156 accidents were prevented in the period of the safety programme which translates to an average of 19.45 per year. The safety programme also saved lives and property worth N 20.2 million for the eight year period which is at an average of N 2.5 million annually. The computation of efficiency indices due to the use of all the input resources when compared with the standard period and it was discovered that all the resources were well utilised. The significance and benefits of the work to the local community and other industries is that the principles of statistical expectation and efficiency index can be easily applied to analyse the performance of safety programme in the industries. @JASEM
Formulation of Silicon Carbide Abrasives from Locally Sourced Raw Materials in Nigeria
A. O. Odior,F. A. Oyawale
Lecture Notes in Engineering and Computer Science , 2011,
Abstract:
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