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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

Sol-Gel Spin Coating Synthesis of TiO<sub>2</sub>Nanostructure and Its Optical Characterization

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Journal of Materials Science and Chemical Engineering 2019年第6期7卷 23-34页

作者： Simeon Amole Mojoyinola Kofoworola Awodele Oluwaseun Adedokun Momodu Jain ayodeji Oladiran awodugba Department of Pure and Applied Physics Ladoke Akintola University of Technology Ogbomoso Nigeria Department of Physics The University of The Gambia Brikama Campus The Gambia

This work focuses on the sol-gel spin coating technique of TiO2 nanostructure synthesis and its characterization. Though various methods have been used to fabricate TiO2 nanostructure, much effort has not been exerted to achieve better photoresponsive and narrowly dispersed TiO2 nanostructure using the sol-gel spin coating method. Therefore, it is imperative to realize the synthesis of TiO2 nanostructures, and investigate their properties. In this work, TiO2 is synthesized by sol-gel spin coating technique using titanium tetraisopropoxide, isopropanol, acetic acid and deionized water as starting materials and deposited on borosilicate glass substrates. The effects of annealing temperatures (300˚C, 400˚C and 500˚C) on the structural and optical properties of the films were investigated by different techniques: Scanning Electron Microscopy (SEM), optical microscopy and UV-visible spectrophotometry. The optical characterization showed the direct band gap at 3.7 eV, 3.6 eV and 3.4 eV for 300˚C, 400˚C and 500˚C, respectively, and the optical transmittance and reflectance spectra showed a greater performance at 500˚C. The grain sizes obtained from SEM annealed at 300˚C, 400˚C and 500˚C are found to be about 6.0 nm, 5.0 nm and 4.0 nm respectively. The grain size of TiO2 nanostructure films decreased with increasing annealing temperatures. The results clearly indicated that the sol-gel spin coating synthesis of TiO2 nanostructure and post-thermal treatment at 500˚C cooled naturally at room temperature result in better photoresponsive and narrowly dispersed TiO2 nanostructure films with higher photoresponsive and good optical properties.

关键词： TiO2 Sol-Gel Spin Coating Grain Sizes Nanostructure Annealing Temperature

Basement data of the Terrestrial Radionuclide Level of Abuja Federal Capital Territory, (FCT), Nigeria

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Journal of Environmental Protection 2011年第4期2卷 359-364页

作者： ayodeji awodugba Adetayo Abioye Dauda Adekunle Omowumi Ologun Isiaka Oyekunle Olatunde Oni Pascal Tchokossa Centre for Energy Research and Development Obafemi Awolowo University Ile-Ife Nigeria Department of Pure & Applied Physics Ladoke Akintola University of Technology Ogbomoso Nigeria Department of Pure & Applied Physics Ladoke Akintola University of Technology Ogbomoso Nigeria Department of Pure & Applied Physics Ladoke Akintola University of TechnologyOgbomoso Nigeria

A total of 30 samples were collected from six different locations from of Abuja Federal Capital Territory (FCT), the administrative capital of Nigeria which is situated in the central part of the country. The samples which were thor-oughly prepared following known dosimetry procedures were analyzed for 40K, 238U and 232Th by the method of Gamma ray spectrometry using NaI(TL) detector coupled to a multichannel analyzer. The activity concentrations in the top soils in these locations for 40K, 238U and 232Th range from 301 ± 26.52 to 928.84 ± 80.57, Not detectable (ND) value to 27.68 ± 8.21 and 4.65 ± 1.46 to 22.48 ± 5.26 respectively. The average absorbed dose rate and the annual effective dose equivalent were found to be 40.33 nGyh–1 and 49.46 μSv respectively. The value of annual effective dose equivalent is low compared to the world average of 70 μSv specified by UNSCEAR for an outdoor effective dose, hence the chances of radiological hazards to the health of the populace are generally low.

关键词： Gamma Ray Spectrometry Soil Radionuclides Abuja FCT Nigeria

Quantification of wing and body kinematics in connection to torque generation during damselfly yaw turn

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Science China(Physics,Mechanics & Astronomy) 2017年第1期60卷 32-41页

作者： Samane Zeyghami ayodeji T. Bode-Oke HaiBo Dong Department of Mechanical and Aerospace Engineering University of Virginia Charlottesville 22903 USA

This study provides accurate measurements of the wing and body kinematics of three different species of damselflies in free yaw turn fights. The yaw turn is characterized by a short acceleration phase which is immediately followed by an elongated deceleration phase. Most of the heading change takes place during the latter stage of the flight. Our observations showed that yaw turns are executed via drastic rather than subtle changes in the kinematics of all four wings. The motion of the inner and outer wings were found to be strongly linked through their orientation as well as their velocities with the inner wings moving faster than the outer wings. By controlling the pitch angle and wing velocity, a damselfly adjusts the angle of attack. The wing angle of attack exerted the strongest influence on the yaw torque, followed by the flapping and deviation velocities of the wings. Moreover, no evidence of active generation of counter torque was found in the flight data implying that deceleration and stopping of the maneuver is dominated by passive damping. The systematic analysis carried out on the free flight data advances our understanding of the mechanisms by which these insects achieve their observed maneuverability. In addition, the inspiration drawn from this study can be employed in the design of low frequency flapping wing micro air vehicles （MAV＇s）.

关键词： damselfly yaw turn angle of attack low flapping frequency wing kinematics flapping flight dynamics

ED-SWE:Event detection based on scoring and word embedding in online social networks for the internet of people

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Digital Communications and Networks 2021年第4期7卷 559-569页

作者： Xiang Sun Lu Liu ayodeji Ayorinde John Panneerselvam School of Informatics University of LeicesterUK School of Computer Science and Telecommunication Engineering Jiangsu UniversityJiangsuChina

Online social media networks are gaining attention worldwide,with an increasing number of people relying on them to connect,communicate and share their daily pertinent event-related *** detection is now increasingly leveraging online social networks for highlighting events happening around the world via the Internet of *** this paper,a novel Event Detection model based on Scoring and Word Embedding(ED-SWE)is proposed for discovering key events from a large volume of data streams of tweets and for generating an event summary using keywords and top-k *** proposed ED-SWE model can distill high-quality tweets,reduce the negative impact of the advent of spam,and identify latent events in the data streams ***,a word embedding algorithm is used to learn a real-valued vector representation for a predefined fixed-sized vocabulary from a corpus of Twitter *** order to further improve the performance of the Expectation-Maximization(EM)iteration algorithm,a novel initialization method based on the authority values of the tweets is also proposed in this paper to detect live events efficiently and ***,a novel automatic identification method based on the cosine measure is used to automatically evaluate whether a given topic can form a live *** conducted on a real-world dataset demonstrate that the ED-SWE model exhibits better efficiency and accuracy than several state-of-art event detection models.

关键词： Internet of people Hyperlink-induced topic search Event detection Online social networks

Enhancement of Large Renewable Distributed Generation Penetration Levels at the Point of Common Coupling

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Energy Engineering 2022年第6期119卷 2711-2744页

作者： Akinyemi ayodeji Stephen Kabeya Musasa Innocent Ewean Davidson Department of Electrical Power Engineering Durban University of TechnologyDurban4000South Africa

The occurrence of distortion and over voltage at the Point of Common Coupling(PCC)of Renewable Distributed Generation(RDG)limits its penetration levels to the power system and the RDG integration is expected to play a crucial role in power system *** its penetrations to be sustained without disconnection from the system,there must be a solution to the voltage rise,distortion,unbalanced current and grid reactive power control strategy at *** is an IEEE-1547 requirement that RDG integration to the power system should be regulated at PCC to avoid disconnection from the network due to power quality *** integration must meet up with this specification to uphold power quality and avoid damage to the sensitive equipment connected at *** this paper,voltage rise,unbalanced current,reactive power and distortion are being managed at PCC while Distribution Network(DN)accepts more RDG penetration levels without violation of the IEEE and South Africa grid code *** Power Filter and Full Bridge Multi-Level Converter(FBMC)are considered to safeguard power quality to the grid,they are modelled in MATLAB/SIMULINK and the results obtained shown that the proposed strategy can successfully regulate voltage rise,distortion,unbalanced current and continuously improve power quality with RDG integration at *** proposed method’s key innovation is the strategic generation and absorption of reactive power to curtain an overvoltage,reverse power flow,and distortion at the PCC,allowing more RDG penetration levels to the grid without disconnection while maintaining the standard requirement for power quality at the *** simulation outcomes validate the superiority of the FBMC over the active power filter with respect of reactive power generation/absorption,dynamic response,and damping capability.

关键词： Electrical circuit reactive power voltage rise distortion and power quality

Exposure of children to heavy metals from artisanal gold mining in Nigeria:evidences from bio-monitoring of hairs and nails

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Acta Geochimica 2020年第4期39卷 451-470页

作者： Adeniyi JohnPaul Adewumi Temitope ayodeji Laniyan Tangfu Xiao Yizhang Liu Zengping Ning Department of Geological Sciences Achievers UniversityOwo.Ondo StateNigeria Department of Environmental Health Sciences College of MedicineUniversity of IbadanIbadanOyo StateNigeria Key Laboratory for Water Quality and Conservation of the Pearl River Delta Ministry of EducationGuangzhou UniversityGuangzhou 510006China School of Environmental Science and Engineering.Guangzhou University Guangzhou 510006China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

In recent times,there had been reported cases of Pb poisoning in Anka gold mining area,Northwest ***,this study was carried out to determine the extent of bioaccumulation of heavy metals in the hairs and nails of children in the *** samples(twenty nails and twenty hairs)samples were collected from ten boys and ten girls of ages 5–9 residing in the *** ascertain the sources of heavy metals in children,15 soils samples,15 groundwater samples,5 samples of mine tailings,and 5 plants samples were *** and nails of the subjects were collected using internationally acceptable *** samples were kept in uncontaminated ziplock bags prior to laboratory preparation and *** samples were cleaned using nonionic detergent(triton X-100)and deionized *** hairs and nails were digested with 10 mL of 6:1 mixture of nitric acid and perchloric *** soils,mine tailings,and plants were air-dried at room temperature,sieved,and chemically digested using the aqua regia *** concentrations of metals in all the samples were determined using highperformance liquid chromatography–inductively coupled plasma–mass *** analysis was employed to unravel potential sources of metals in the *** showed that heavy metals in children of the area are above results from similar studies and pathological ranges for heavy metals in hairs and ***,heavy metals in environmental media are above the recommended *** analysis showed that the metals are mainly from mining and other anthropogenic *** of correlation between heavy metals in hairs and nails with those in geological samples revealed that heavy metal that bioaccumulates in the children of this area are mostly from contaminated environmental *** is recommended that complete remediation and effective health education be carried out in the area.

关键词： Anka Bioaccumulation Children Heavy-metals Hairs Nails

The Influence of Employment Characteristics and Grievance Mechanism on Employees' Grievance Behavior

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The Influence of Employment Characteristics and Grievance Me...

作者： Abe Alexander ayodeji 湖南大学

学位级别：硕士

任何组织都无法完全消除员工不满和抱怨。组织有效性、员工绩效与员工满意密切相关,而员工满意又受到组织氛围的影响。具有不同的个性、目标、期望和经验的人在一起,组织必须建立良好的员工关系管理系统和员工申诉机制,以有效管理员工... 详细信息

任何组织都无法完全消除员工不满和抱怨。组织有效性、员工绩效与员工满意密切相关,而员工满意又受到组织氛围的影响。具有不同的个性、目标、期望和经验的人在一起,组织必须建立良好的员工关系管理系统和员工申诉机制,以有效管理员工可能遇到的任何不满问题。本研究旨在探讨员工个体特征和企业申诉机制对员工申诉行为的影响。本研究对尼日利亚三个主要城市的三个经营最好的银行的300名雇员发放员工申诉问卷,有效问卷241份。使用描述统计、相关分析、回归分析,探索因果关系,验证提出的假设。研究发现,员工的性别、年龄、教育程度、雇佣年限、雇佣形式等影响员工申诉行为及对企业申诉处理机制的满意度;员工的法律意识、工作强度、工资水平和领导能力等因素与申诉处理行为显著相关;管理者因素如处理员工不满情绪的技巧和速度与员工申诉行为显著相关;企业员工申诉处理机制如信息获取的便捷性、信息的完整充足性、申诉处理机制效率、申诉处理的有效性等与员工申诉行为呈负相关。本研究综合组织、制度和个体等因素,探索组织因素与员工个体因素与员工申诉行为之间的因果关系,综合前人零散的研究,构建一个组织和个体因素与员工申诉的因果逻辑的整合框架;而且本研究提供了尼日利亚的经验证据。根据研究结果,企业有必要建立及时有效的申诉处理机制,以和平的方式运作,通过解决纠纷来减少员工面临的恐惧和压力;通过识别和解决员工不满,在申诉产生之前迅速采取行动,减少申诉。此外,需要对经理或主管进行培训和再培训,以提高他们成功管理员工抱怨和不满的能力,提高员工满意度,进一步提高组织效率。

关键词：员工特征申诉机制组织政策员工申诉行为

Enhanced Electric Power Adaptability Using Hybrid Pumped-Hydro Technology with Wind and Photovoltaic Integration

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Energy Engineering 2023年第9期120卷 1939-1961页

作者： Uwem O.Ikitde Abayomi A.Adebiyi Innocent E.Davidson ayodeji S.Akinyemi Department of Electrical Power Engineering Durban University of TechnologyDurban4001South Africa Department of Electrical Electronics and Computer EngineeringCape Peninsula University of TechnologyBellville7535South Africa

The integration of solar and wind energy into the electrical grid has received global research attention due to their unpredictable *** wind energy varies across all timescales of utility activity,renewable energy generation should be supplemented and enhanced,from real-time,minute-to-minute variations to annual alterations influencing *** energy generation does not only fluctuate but is also challenging to accurately forecast the timeframes of significance to electricity decision makers;day-ahead and long-term making plans of framework sufficiency such as meeting the network peak load annually.A utility that integrates wind and solar energy into its electricity mix would understand how to adapt to uncertainty and variability in operations while sustaining grid *** to hydropower’s adaptability,a system using hydropower as one of its generating resources could be precisely adapted to absorb the variability of wind and solar *** objective of this research study is to create a hybrid system comprising hydro-wind and solar(Hybrid-HWS)integration for power balancing in an isolated electrical network in Klipkop village,Pretoria region,South *** desirability of designing and building goaf storage tank in regard to capability,the fullness of line throughoutwater pumping,dispensing,storage tank spillage,and pressure difference throughout liquid flow within the storage tanks were preliminary assessed using geotechnical and weather forecasting data from a distinctive area of Klipkop town in Pretoria,South *** facility hours premised on daylight accessibility are scheduled to balance maximum load at early and late ***,in the scenario of electrical power,time shift requiring storage for extended periods of time,such as in terms of hours,Hybrid-HWS has been found to have a crucial *** results of simulations showed a coordinated process design for Hybrid-HWS Energy Storage(ES)to determine ev

关键词： Pumped hydro storage(PHS) hybrid hydro-wind-solar technique abandoned coal mine power balancing