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Propulsion and Power Research 2018年第4期7卷 342-352页

作者： Taiwo S.Yusuf michael o.oni Department of Mathematics Ahmadu Bello UniversityZariaNigeria

This paper investigates the combined effect of radial magnetic field and viscous dissipation on entropy generation in horizontal co-axial cylinders of generalized Couette *** analytical solutions for velocity and temperature profiles are obtained and utilized to compute the entropy generation,Bejan number as well as the average entropy generation *** effect of relevant parameters on temperature field,velocity field,entropy generation,average entropy and Bejan number are portrayed graphically and *** isoflux heating near the inner surface of the fixed outer cylinder with higher dominance in the case of isoflux *** reverse is seen on the moving inner cylinder.

关键词： Radial magnetic field Viscous dissipation Generalized Couette flow Isothermal Isoflux Entropy generation

Natural convection flow in a vertical annulus with time-periodic thermal boundary conditions

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Propulsion and Power Research 2019年第1期8卷 47-55页

作者： Basant K.Jha michael o.oni Department of Mathematics.Ahmadu Bello University Zaria.Nigeria

This paper presents an analytical solution for natural convection flow in a vertical annulus due to time-periodic heating of annulus ***-form expressions for velocity,temperature,skin-friction,mass flow rate and rate of heat transfer which is expressed as Nusselt number are obtained by solving the present mathematical model after separating into steady component and periodic *** effects of pertinent parameters such as Strouhal number(St),Prandtl number(Pr)and radius ratio(λ)are shown with the aid of contour and line *** indicate that the role of Strouhal number and Prandtl number is to decrease fluid velocity,temperature and ***,increase in Strouhal number increases the temperature phase-lag.

关键词： Natural convection Fully developed flow Time-periodic heating Vertical annulus Strouhal number

Joule heating and viscous dissipation effect on electroosmotic mixed convection flow in a vertical microchannel subjected to asymmetric heat fluxes

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Propulsion and Power Research 2021年第1期10卷 83-94页

作者： michael o.oni Basant K.Jha Department of Mathematics Ahmadu Bello UniversityZariaNigeria

The impact of Joule heating due to electric double layer(EDL)and viscous dissipation on electroosmotic mixed convection flow in a vertical microchannel with asymmetric heat fluxes is established in this *** Poisson-Boltzmann,momentum and energy equations representing the electric potential,velocity profile and temperature distribution in the microchannel are obtained in dimensionless *** the Debye-Hückel linearization,exact solutions are obtained for electric potential,velocity profile and temperature distributions by method of undetermined coefficients in the absence of viscous dissipation and Joule heating while an inbuilt Matlab function called pdepe is employed to solve the coupled nonlinear momentum and energy equations in the presence of Joule heating and viscous *** show that the presence of Joule heating and viscous dissipation lead to decrease in velocity profile and temperature distributions throughout the microchannel.

关键词： Electroosmotic flow Vertical microchannel Joule heating Heat flux Viscous dissipation

Natural Radionuclide Concentrations and Radiological Impact Assessment of River Sediments of the Coastal Areas of Nigeria

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Journal of Environmental Protection 2011年第4期2卷 418-423页

作者： olatunde michael oni Idowu Peter Farai Ayodeji oladiran Awodugba Department of Physics University of Ibadan Nigeria Department of Pure and Applied Physics Ladoke Akintola University of Technology Ogbomoso Nigeria

This work was carried out to measure the radioactivity level in the coastal areas of Nigeria by gamma counting of river sediment samples and assess the radiological impact associated with the use of the river sediments as building material. The method of gamma spectrometry with a 7.6 cm by 7.6 cm NaI(Tl) detector was employed in determining 40K, 238U and 232Th levels in 95 and 38 sediment samples respectively collected from representative sites in the oil producing and non oil producing coastal areas of Nigeria. Results of the samples assayed showed that the radioactivity concentrations of 40K, 226Ra and 228Ra in the sediment samples of oil producing areas range from 95.4 to 160.0;7.6 to 31.0 and 9.5 to 41.6 Bq kg–1, respectively. The respective means were calculated as 122.39 ± 47.49;18.93 ± 12.53 and 29.31 ± 18.67 Bq kg–1. In the sediment samples from the non oil producing areas, the respective mean values are 88.48 ± 8.22, 14.87 ± 3.51 and 16.37 ± 3.87 Bq kg–1. Statistical analysis of the results showed that there is no significant difference between the radionuclide concentration of the sediment samples from different rivers in the oil producing and non oil producing coastal areas, except for 40K. The values of the natural radionuclide concentrations however translate to the determina-tion of the radiological impact assessment values. The values of the radiological assessment indices obtained were ob-served to be lower than limits internationally reported and recommended for building materials. It could therefore be reported that the operations of the oil companies in the coastline, involving use of radioactive materials have not contributed adversely to the radioactivity level of the river sediments and that the use of river sediments as building mate-rial in the coastal areas of Nigeria poses no radiological risk.

关键词： Radiological Risk Indices River Sediments In Coastal Area Gamma Spectrometery

Development of a Novel oven-Furnace

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Journal of Minerals and Materials Characterization and Engineering 2017年第2期5卷 62-73页

作者： olaniyi Gladius Babatunde Rufus Sola Fayose Ayodele Abeeb Daniyan Theresa Chikwuo Ezenwafor Ebenezer olubanji oniya Nathaniel o. Ajayi Kunle michael oluwasegun Akintoye oni Adedeji Akintunde Ajenifuja Arinola Gift Akinseloyin Adelana Razak Adetunji Samuel oloruntoba olugbenga olusunle Adekunle Ajasin University Akungba Akoko Nigeria Engineering Materials Development Institute Akure Nigeria obafemi Awolowo University Ile-Ife Nigeria

This research work is focused on the design and fabrication of Novel oven-Furnace, using locally sourced materials for the purpose of carrying out drying and thermochemical treatments in accordance to the International Electric Equipment (IEE) regulations. Working drawings were produced, and mild steel sheet was used for the construction of the casing, while other materials for the construction were selected based on functions and properties of the materials, cost considerations and ease of fabrication into component parts. The design closely revealed the parameters and features of the furnace, but the control system was designed to function systematically as oven and Furnace. Testing was carried out to evaluate the performance of the oven-Furnace. From the result obtained, it was observed that the oven-Furnace has fast heating rate which is comparable to rates of conventional brands of furnaces purchased from Germany or Canada. Unlike the ordinary furnaces, this equipment was designed to operate systematically to maintain constant temperature at any set temperature value. The lower cost of design of the oven-Furnace coupled with its good heat retaining capacity, long estimated life time, uniform heating rate, controlled atmosphere, safety and ease of maintenance justifies the usage.

关键词： Design oven-Furnace Constant Temperature Drying Thermochemical Treatment Systematic Function Control System

Reviewing the oceanic Nino Index(oni) to Enhance Societal Readiness for El Nino’s Impacts

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International Journal of Disaster Risk Science 2020年第3期11卷 394-403页

作者： michael H.Glantz Ivan J.Ramirez Consortium for Capacity Building/INSTAAR.University of Colorado BoulderCO 80309USA Department of Health and Behavioral Sciences University of Colorado DenverDenverCO 80204USA

NoAA’s oceanic Nino Index(oni)is used to record for historical purposes the occurrence and duration of El Nino episodes,based on the monitoring of sea surface temperatures(SSTs)in the central Pacific *** oni is used to identify the onset of an above average SST threshold that persists for several months,encompassing both the beginning and end of an El Nino *** first appearance of an anomalous seasonal value of 0.5℃suggests with a high probability that an El Nino could emerge,but for heightened warnings,one must wait for several *** this article,we proposed that the oni value of 0.7℃identifies a tipping point at which the El Nino event becomes locked in,which can provide additional lead time for mitigative actions to be taken by societal decision *** preliminary findings suggest that a first appearance of 0.7℃value could serve as a credible marker of El Nino’s locked-in phase,which can provide additional credibility to the current 0.5℃El Nino onset indicator for at-risk societies to get ready for El Nino’s foreseeable societal and ecological impacts.

关键词： Advisory Disasters Early warning El Nino El Nino Southern oscillation ENSo Hydrometeorological hazards oceanic Nino Index oni