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Mechanical and Rheological Characteristics of Micro-Particle Maize Tassel-Filled Polypropylene Micro-Composites

材料科学与工程（中英文B版） 2011年第2期1卷 131-147页

作者： Emmanuel Rotimi Sadiku Annet Chacko Lekgethile Mable Karabo Kekana Goitseona Phiri Jonathan Okechukwu Okonkwo Caliphs Musa Zvinowanda Mahlatsa Mapula Sekhula nana mensah agyei Department of Mechanical Engineering （Polymer Technology） Tshwane University of Technology CSIR Campus Lynnwoodridge 0400 Rep. of South Africa Department of Environmental Water and Earth Science Faculty of Science Tshwane University of Technology Pretoria 0001 Rep . of South Africa Department of Chemistry University of Limpopo Medunsa 0204 Rep. of South Africa

Maize tassel was pulverized into micro-particulate size. The tassel particles, at various degree of loading (ranging between 0-10%), were used as fillers, in polypropylene. The resulting mixtures were melt-extruded, pelletized, moulded into tensile test specimens and tested for their rheological performance and mechanical integrity. Activation energy, a E Δ, of flow from rheological tests increases with % tassel loading. This implies that increase in tassel loading impedes smooth pliability of the composites, since higher energy for flow is needed for ease processability as the tassel loading increases. The improvement in stiffness with tassel content is the expected effect, caused by the addition of rigid filler into the semi-rigid matrix and dynamic storage modulus " G change in the transition of the composites appears smaller than that of the virgin PP. The decrease in " G (10% tassel loading) at 190 oC with respect to neat PP in the glassy region could be as a result of agglomeration of particles due to high load loss. The % strain decreases asymptotically as a function of tassel loading, while tensile strength grows asymptotically. The work-of-rupture (area under the stress vs. strain curve) decreases with % tassel loading with a polynomial model, having a coefficient of fit, R2 of ~0.9956. Tensile strength (polynomially modeled), decreased with increasing tassel loading, with a coefficient of fit, R2 of ~0.9979. This is attributed to the different polarities of the components of the composite, resulting from the non-use of a coupling agent. Generally, there is an increase in the Young’s modulus with increasing tassel loading. For instance, at 10% tassel loading, the Young’s Modulus improved only by about 1? folds the value of the virgin PP. A linear model for the Young’s Modulus did not produce a strong coefficient of fit (R2 of ~0.7701) when compared to the tensile strength. Impact strength decreased exponentially with increasing tassel loading (R2 ~0.8504).

关键词：填充聚丙烯复合材料微观粒子流变特性力学性能雄穗玉米多项式模型

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Lip print enhancement: review

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Forensic Sciences Research 2022年第1期7卷 24-28页

作者： Maxwell Abedi Constance Afoakwah Dan nana Osei mensah Bonsu Institute of Forensic Science Gujarat Forensic Sciences UniversityGandhinagarGujaratIndia Department of Forensic Sciences University of Cape CoastCape CoastGhana

Lip print(LP)evidence can be an essential tool for human *** have conventionally been developed using substances such as lysochrome dyes,fluorescent dyes,indigo dye,aluminium powder,and silver metallic ***,techniques for LP enhancement from various substrates are currently inconsistent and lack standardisation in *** review summarises current knowledge on the physical and chemical techniques of LP enhancement,identifies limitations,and provides suggestions for future research on practical applications of cheiloscopy as a forensic tool in criminal justice.

关键词： Forensic sciences cheiloscopy lip print lysochrome fluorescent dye persistent lipstick

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Relationship between Corporate Image and Customer Loyalty in the Mobile Telecommunication Market in Kenya

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Management Studies 2014年第5期2卷 299-308页

作者： Paul mensah agyei James M. Kilika University of Cape Coast Cape Coast Ghana Kenyatta University Nairobi Kenya

Customer loyalty is considered to be a key ingredient in enhancing the survival of businesses especially in the situations faced by highly competitive industries. This study assessed the relationship between corporate image and customer loyalty. While the antecedents of customer loyalty connected with the marketing mix factors have been well investigated, much still remains to be studied regarding some of the intermediate conditions created by the marketing mix factors and customer loyalty. This study sought to investigate the relationship between the dimensions of corporate image and customer loyalty in the mobile telecommunication market in Kenya. The study was guided by several hypotheses that tested the nature of the relationship between corporate image and customer loyalty using four dimensions of corporate image, namely service quality, chief executive officer （CEO） reputation, brand image, and physical evidence. The study adopted the descriptive survey research design and used a multi-stage stratified sampling technique to target 320 respondents from among students across campuses of Kenyatta University （KU）. Primary data was obtained using a structured five-point Likert scale questionnaire and analyzed using Pearson product-moment correlation coefficient and regression analysis to test the degree of association between the dependent and the independent variables. The study registered a high response rate of 97.8% from the target respondents. The findings of the study based on the correlation analysis indicated that the four dimensions of corporate image positively correlate with customer loyalty at p 〈 0.01. The regression analysis results however showed that even though the four dimensions correlate with customer loyalty, only service quality and brand image significantly predict customer loyalty. The regression model used explained 25% variation in the dependent variable. The null hypotheses one and four were supported while hypotheses two and three were n

关键词： customer loyalty corporate image telecommunication service quality brand image physical evidence reputation consumer behavior

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软件定义车载网络下任务卸载和资源分配联合优化研究

软件定义车载网络下任务卸载和资源分配联合优化研究

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作者： mensah RICHARD nana KOJO 江苏大学

学位级别：硕士

车载自组织网络(VANETs)作为智能交通系统(ITSs)的关键技术受到了学术界和工业界的广泛关注。随着车辆应用和数据的爆炸式增长对当前数据通信、算力、存储资源、网络延迟以及无线网络容量都提出了更高的性能需求。为了应对新的性能需求... 详细信息

车载自组织网络(VANETs)作为智能交通系统(ITSs)的关键技术受到了学术界和工业界的广泛关注。随着车辆应用和数据的爆炸式增长对当前数据通信、算力、存储资源、网络延迟以及无线网络容量都提出了更高的性能需求。为了应对新的性能需求挑战,车载边缘计算(VEC)被认为是一种解决当前矛盾的新型计算范式,它将计算能力下沉到车辆网络的边缘,允许车辆中的路边单元(RSU)和车载单元(OBU)等节点执行具有位置感知和低延迟需求的服务。此外,车载边缘计算还能有效地缓解网络上大量数据请求造成的网络拥塞。车载边缘任务卸载是实现车载边缘任务处理这一美好愿景的关键技术问题。然而,由于车辆节点的强移动性及拓扑的频繁变化给车载任务卸载和任务处理带来新的技术挑战。文章的主要工作如下:首先,采用博弈论方法设计了一种任务卸载决策模型以优化VEC环境下的任务处理能力。在这种场景下,移动节点通过测试连接一组边缘计算服务器,在本地自主地决定应该选择哪台边缘服务器节点进行卸载,以便优化执行计算任务的序列。鉴于此,将任务卸载决策过程建模为一个博弈模型。其次,VEC与VANET中的设备到设备(D2D)任务卸载相结合,以受益于邻近增益并优化计算卸载。开发了软件定义车载边缘计算网络(SD-VEN),通过感知全局网络状态信息实现对网络的全局优化。SD-VEN中的控制器能够协调端边云之间的资源优化部署和处理,协调D2D配对和通信,以实现车辆节点与移动用户之间灵活分配计算资源。对该模型的研究可以优化车辆网络在通信和计算受限制情况下资源分配。在此,将任务卸载和相关的资源分配联合优化问题形式化为一个混合策略的博弈问题。第三,采用资源池的概念,通过将车辆及其乘客设备可用的边缘计算资源集中在一起,来增强系统的容量。数值评估讨论了所提出模型与随机卸载、均匀卸载、边缘任务卸载和最近邻对等任务卸载等情形下的模型性能差距。定性和定量分析了任务卸载对参与者效用的影响。实验结果表明,如果卸载的任务数保持不变,则可以有效地达到平衡。此外,在动态任务卸载的仿真实验中,实验结果表面博弈仍然能够收敛到均衡,一旦博弈达到接近稳定的状态,只需进行少量的策略更改。综上所述,文章将任务卸载决策过程建模为一个博弈模型,首次提出将D2D引入到车载边缘计算网络中,在不增加额外成本的情况下,增强了网络系统的容量且提高边缘资源的利用率。之后,还将SDN网络引入到该场景下,通过SDN控制器感知网络交互状态实现全局网络的最优任务卸载和全局资源的最优化管理。理论和实验结果均表明,文章提出的基于博弈的车载任务卸载策略可以在优化任务卸载决策方面发挥重要的作用。数值仿真结果显示所提出的模型实现的平均处理时间比现有方法提高了25%。

关键词：边缘计算车载任务卸载软件定义网络博弈论多设备智能互联

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Do Farmers Respond to Training？--The Case of the Millennium Challenge Account （MCA）-Ghana Programme

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Journal of Food Science and Engineering 2013年第11期3卷 592-608页

作者： Robert Darko Osei Isaac Osei Akoto Andrew agyei-Holmes Hayford mensah Ayerakwa Institute of Statistical Social and Economic Research University of Ghana Legon Accra Ghana Development Policy and Practice the Open University Milton Keynes MK7 6AA United Kingdom

This study examined the effect of farmer business, technical training and input provision through a government intervention programme on productivity and crop incomes among Farmer Based Organizations （FBO） in Ghana. Farm level data were collected from 2,900 farmers over 11,000 farm plots. The difference-in-difference estimator is employed to test the impact of this intervention on crop yields and incomes. Farmers were randomly put into two distinct groups： the treatment （early training） and control （late training）. After the collection of baseline data, the treatment group received crop husbandry training and a starter pack which included inputs and cash both worth about US$230. The control group received the intervention after a year. The main findings of this study are that the intervention does not have any significant impact on crop yields and crop incomes. However the authors do find some evidences that as a result of the intervention, the value of chemicals used by farmers decreased by about GH^25 The study concludes by noting that although some changes do occur over the period, and it is not possible to attribute these changes to the MiDA training programme for all the indicators of interest except chemical costs.

关键词： Agriculture productivity farmer incomes training.

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Cold-Weather Crop Suitability Modelling

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Open Journal of Soil Science 2023年第10期13卷 431-455页

作者： Kamille Lemieux nana-agyei O. Afriyie Shane Furze Patrick Toner Paul A. Arp Faculty of Forestry & Env. Management University of New Brunswick Fredericton Canada NB Dept. Agriculture & Aquaculture Hugh John Flemming Forestry Centre Fredericton Canada

This article presents ArcGIS Pro workflow results aimed at rating and mapping cold-weather crop suitability from 0% to 100% at 1-m elevation resolution for the Province of New Brunswick (NB). This rating accounts for variations by soil conditions (texture, coarse fragments, depth, calcareousness, drainage, slope), growing degree days (GDD) and frost-free days (FFD) from within fields to across regions. The ratings so produced reflect a significant part of farm and farm/woodlot property assessment values as these also vary by area and building footprint. While the soil properties for texture, coarse fragments, depth, and calcareousness vary by NB soil association mapping units, within-field suitabilities also vary by slope from flat to steep and by drainage as it correlates across the terrain by depth-to-water (DTW) from very poor to poor, imperfect, moderate, well and excessive. Areas marked by 1.5 10% have low to no suitability because of slope-increased soil erosion and trafficability risks. The number of growing-degree and frost-free days across NB were rated to be sufficient for cold weather cropping, except marginally so at the high-elevation locations.

关键词： Crop Suitability Rating Topography Climate Soil Properties Property Values Regression Analysis

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Evaluating Added Benefits from Combined Cattle Manure and Fertilizer Application in a Maize Cropping System

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Journal of Environmental Science and Engineering(B) 2017年第1期6卷 34-40页

作者： Mavis Badu Brempong Andrews Opoku nana Ewusi-mensah Robert Clement Abaidoo Department of Crop and Soil Sciences Kwame Nkrumah University of Science and Technology Kumasi Ghana College of Agriculture and Natural Resources Kwame Nkrumah University of Science and Technology Kumasi Ghana International Institute of Tropical Agriculture (IITA) lbadan Nigeria

A field experiment was conducted at Kpongu in the Upper West region of Ghana to determine the added benefits in grain yield of maize derived from the concurrent use of manure and mineral fertilizer, and their cost effectiveness. Factorial combinations of cattle manure and mineral fertilizer each at 0, 50 and 100% of their recommended rates were evaluated in both the field and the laboratory studies. The treatments were applied in a randomized complete block design with three replications on the field. The same treatments were applied in the incubation study in a completely randomized design. The use of 100% NPK （Nitrogen, Phosphorus, Potassium）＋ 5 t manure gave the highest grain yield of 4,678 kg·ha^-1. Synergistic interactions resulting in added benefits in grain yield were observed in all the combined nutrient inputs except 50% NPK ＋ 2.5 t manure which accrued an added disadvantage of 44 kg·ha^-1. Economic analysis proved that 100% NPK ＋ 2.5 t manure and 50% NPK ＋ 5 t manure were the most economically viable combined treatments in terms of grain yield. Based on the results from this study, resource poor farmers in the Upper West region of Ghana may reduce mineral fertilizer recommended rates by 50% and supplement it with 5 t quality （N 〉2.5%） cattle manure without compromising yield and profit.

关键词： Synergistic interaction yield value cost ratio.

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Comparison of Rainy Season Onset, Cessation and Duration for Ghana from RegCM4 and GMet Datasets

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Atmospheric and Climate Sciences 2016年第2期6卷 300-309页

作者： Caleb mensah Leonard K. Amekudzi nana Ama B. Klutse Jeffrey N. A. Aryee Kofi Asare Ghana Meteorological Agency Accra Ghana Meteorology and Climate Science Unit Department of Physics Kwame Nkrumah University of Science and Technology Kumasi Ghana Remote Sensing GIS and Climate Center Ghana Space Science and Technology Institute Accra Ghana

The socio-economic sector of West African countries is rain-fed agriculture driven. Information regarding the onset, cessation and duration of the rainy season is thus, very essential. In this paper, a comparison of the onset, cessation and duration of the rainy season has been carried out using simulated rainfall data from the fourth generation Regional Climate Model (RegCM4) and rain gauge measurements from Ghana Meteorological Agency (GMet), covering a period of 1998 to 2012. Similar onset and cessation dates were seen in both the simulated and guage rainfall measurements for the various agro-ecological zones, resulting in similar duration of the rainy season. The average duration of the rainy season were less than 200 days for the savannah and coastal zones whereas the duration of the rainy season were beyond 200 days for the forest and transition zones. The bias of these comparisons was less than 30 days and the root mean square error (RMSE) values were less than 15 days for all stations, except Saltpond. The Pearson’s correlation (r) typically ranged between 0.4 and 0.8. However, negative correlations were observed for Tamale in the savannah zone, and the entire coastal zone. These findings are indications that RegCM4 has the potential to clearly simulate the movement of the rain belt, and thus, could fairly determine the onset, cessation and duration of the rainy season. The findings have significant contributions to effective water resource management and food security in Ghana, as the thriving of these sectors depend on the dynamics of the rainfall seasons.

关键词： Onset Cessation Duration of Rainy Season GMet Ghana RegCM4

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Does Environmental Laws and Policies Work?A Review Of Ghana’s Case

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Research in Ecology 2020年第3期2卷 32-41页

作者： Aboagye Emmanuel mensah Attobrah Justice Owusu nana Osei Fletcher Henrietta Zhongnan University of Economics and Law WuhanHubei430000China Ocean University of China QingdaoShandong266000China

Enforcing environmental laws and policies has been one of the pressing agenda *** the mandate given to the Environmental Protection Agency(EPA)by the Act 490,there are still numerous environmental issues unaddressed in *** paper is geared towards unravelling and identifying the current additions that have been made to existing literature on environmental laws and policies in *** paper made a wide-ranging general literature review to outline significant contributions concerning environmental laws and *** environmental laws and policies were identified but have been fragmented and are not codified in a particular *** is evident from the review of literature existing that there are still areas for advanced research on the topic of environmental laws and policies placing more emphasis on institution concerned with environmental issues at global *** study recommended the need for capacity building for environmental personnel and data due to the numerous technological advancement to better assist the implementation and enforcement of environmental laws in Ghana.

关键词： Environmental laws Environmental policies Environmental Protection Agency Law enforcement Act 490 Ghana

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