检索结果-南通市图书馆

Impact of Economic Growth,Energy Use and Population Growth on Carbon Emissions in Sub-Sahara Africa

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Science and Engineering(B) 2018年第5期7卷 178-192页

作者： Max William Ssali Jianguo Du Duncan Omenda Duncan Omenda Hongo isaac adjei mensah School of Management Jiangsu University Zhenjiang 212013 PR China School of Statistics Jiangsu University Zhenjiang 212013 PR China Faculty of Science Jiangsu University Zhenjiang 212013 P R of China

The study examines the impact of economic growth,energy use and population growth on carbon emissions in sub Saharan Africa:Kenya,Nigeria,Botswana,Benin,Togo and Mauritius for the period *** study employed unit root test,co-integration test,VECM(Vector Error Correction Model)and FMOLS(Fully Modified Ordinary Least-Square)as methodologies to model the causality and linear relationships amongst the *** VECM was used to identify the long-run causality and asymptotic convergence among the *** results reveal that an increase in energy use and population growth by1%would cause an increase in CO2(Carbon Dioxide)concentration by0.08%and0.22%correspondingly,whereas in the long-run1%increase of energy use increases economic output by0.09%.As the economy grows without contributing to carbon emissions,governments should invest more in renewable *** should also come up with policies to regulate population growth and fossil energy use.

关键词： Carbon emissions economic growth energy use population growth

Effect of Variety and Plant Spacing on Growth and Yield of Groundnuts (Arachis hypogaea L.)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences 2024年第1期15卷 54-70页

作者： Abukari Iddrisu Eric adjei Samuel Kwesi Asomaning Kwadwo Gyasi Santo Adu Poku isaac Alexander Danson-Anokye Cocoa Health and Extension Division Huni Valley Ghana Department of Agriculture Berekum East Municipal Assembly Berekum Ghana Department of Horticulture and Crop Production School of Agriculture and Technology University of Energy and Natural Resources Sunyani Ghana Glenn High School Winston Salem USA

A field experiment was carried out to determine the effect of variety and plant spacing on yield and growth of groundnuts. The field experiment was laid in a 3 × 3 factorial experiment in a Randomized Complete Block Design (RCBD) with three (3) replications. The factor A included three (3) groundnut varieties (Nkatie Sari, Sum Nutt 22 and Yenyawoso) and Factor B was the three (3) spacing of 30 cm × 15 cm, 30 cm × 30 cm and 30 cm × 40 cm. All recommended agronomic practices were followed. Data was collected from eight (8) tagged plants. Growth data were recorded on plant height, number of branches, number of leaves, and the number of flowers while yield data were collected on the number of flowers, number of pods per plant, 100 seeds weight and the pod yield (kg/ha). The plant spacing significantly influenced (P < 0.05) the growth and yield parameters. Groundnut grown at a spacing of 30 cm × 15 cm produced the maximum plant height, whereas the maximum number of leaves, number of branches and number of flowers were produced from 30 cm × 40 cm. Yenyawoso variety with a wider plant spacing performed better vegetatively among all the varieties. The Yenyawoso variety produced the highest number of pods, 100 seeds weight and pod yield as compared to the other varieties. Also, Yenyawoso at 30 cm × 40 cm spacing and Nkatie Sari at 30 cm × 15 cm spacing produced the maximum pod yield.

关键词： Groundnut Variety Yield Spacing Plant Height

A compartmental model to investigate the dynamics of the COVID-19 pandemic:A case study in five countries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2021年第5期14卷 51-63页

作者： Ofosuhene O.Apenteng Bismark Oduro isaac Owusu-mensah Division for Global Surveillance Research Group for Genomic Epidemiology National Food Institute Technical University of Denmark Kongens LyngbyDenmark Department of Mathematics and Physical Sciences California University of Pennsylvania California Pennsylvania 15419USA Department of Science Education University of Education Winneba Mampong-AshantiGhana

Coronavirus Disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infections,was declared a pandemic by the WHO on March 12,*** April 10,2020,it has spread to almost 215 UN Territories,affected more than 1,600,000 people,and become fatal to more than 100,000 *** propose a compartmental model to investigate the dynamics of the COVID-19 pandemic and analyze the effects of governments and health officials’intervention strategies,using data in the USA,Italy,Spain,Germany,and *** are the countries with the most confirmed cases of the COVID-19 as of April 11,*** perform parameter estimations,sensitivity,and predictive analysis and compare the COVID-19 trend in these understudy *** on the model,we compute the basic reproduction number of the pandemic in these *** results indicate that the most sensitive parameters are the contact rate and degree of intervention;these parameters have high value in containing the *** basic reproduction number in each of the countries under study is more than *** on our findings,the COVID-19 pandemic will continue to spread;but higher compliance with the intervention strategies will help minimize the disease’s spread.

关键词： COVID-19 disease parameter estimation sensitivity analysis predictive analysis

Observation Analysis of Decision Tree Extraction from Artificial Neural Network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Observation Analysis of Decision Tree Extraction from Artifi...

作者： isaac KOFI mensah 湖南大学

学位级别：硕士

The ability of artificial neural networks to learn and generalize complex relationships from a collection of training examples has been established though numerous research studies in recent years. The knowledge acquired by neural networks, however, is considered incomprehensible and not transferable to other knowledge representation schemes such as expert or rule-based system.Two of the commonly used techniques are artificial neural networks and decision trees. Artificial neural networks (ANNs) have empirically been shown to generalize well on several machine learning problems. Reasonably satisfactory answers to the questions like how many examples are needed for the neural network to learn a concept and what is the best neural network architecture for a particular problem domain are available in the form of learning theory, so it is now possible to train neural networks without guesswork. This makes them excellent tool for data mining, where the focus is to learn data relationships from huge databases. However, there are applications like credit approval and medical diagnosis where explaining the reasoning of the neural network is important. The major criticism against neural networks in such domains is that the decision making process of neural networks is difficult to understand. This is because the knowledge in the neural network is stored as real-valued parameters of the network, the knowledge is encoded in distributed fashion and the mapping learnt by the network could be non-linear as well as non-monotonic. One may wonder why neural networks should be used when comprehensibility is an important issue. The reason is that predictive have an appropriate inductive bias for many machine learning domains. The predictive accuracies obtained with neural networks are often significantly higher than those obtained with other learning paradigms, particularly decision trees. Decision trees have been preferred when a good understanding of the decision process is

关键词： Rule extraction Decision tree Data mining Classification Knowledge discoveryNeural Netwrork feed forward

Spatial analysis of synergies and trade-offs between the Sustainable Development Goals (SDGs) in Africa

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Geography and Sustainability 2022年第3期3卷 220-231页

作者： Adams Osman Emmanuel Abeashi mensah Collins adjei mensah Yaw Asamoah Suleman Dauda Kofi Adu-Boahen Charles Atanga Adongo Department of Geography Education Faculty of Social Sciences EducationUniversity of EducationWinnebaP.O.Box 25WinnebaGhana Department of Geography and Regional Planning Faculty of Social SciencesUniversity of Cape CoastPrivate Mail BagCape CoastGhana Department of Tourism and Hospitality Management Faculty of Social SciencesUniversity of Cape CoastPrivate Mail BagCape CoastGhana Schools of Tourism and Hospitality University of JohannesburgP.O.Box 524Auckland Park 2006South Africa Emperiks Research Limited Cape Coast Stadium AvenueCape CoastGhana

Challenges faced by African countries in achieving the goals of sustainable development are similar and trans-boundary. Previous analysis of Africa’s progress on the Sustainable Development Goals (SDGs) has largely beennon-spatial, reducing the ability to find spatial relationships between countries and SDGs to help cooperationand proffer country-specific interventions. This study adopted techniques of exploratory and inferential spatialstatistics to assess the successes of African countries from 2016 to 2020 in achieving the goals of sustainable de-velopment. Also, the study sought to understand how the spatial synergies and trade-offs between SDGs vary percountry and time. The results revealed that spatial hotspots of countries with high SDGs scores were mostly con-fined to northern African countries with significant coldspots within central and eastern Africa and few patchesin western and southern Africa for 2016. In 2020, the number of countries forming hotspots reduced, with Cen-tral African countries as significant cold spots. Five main spatial relationships: positive linear, negative linear,concave, convex and undefined complex, were found among countries and the SDGs. However, these spatialrelationships were fluid as they changed over time and with different levels of influence from 2016 to *** study concludes that generic solutions and policies by development agencies, governments, developmentfinance instiutions and other impact investors will not be enough in achieving the SDGs because of the spatialheterogeneity of the continent. Tailored and country-specific policies based on results of spatial statistics matter.

关键词： Africa Development Sustainable development Spatial analysis Hotspots Random forest

Pharmacognostic standardisation of Hilleria latifolia(Lam.) ***.(Phytolaccaceae)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2014年第12期4卷 941-946页

作者： isaac Kingsley Amponsah Abraham Yeboah mensah Antonia Otoo Merlin Lincoln Kwao mensah Jato Jonathan Department of Pharmacognosy Faculty of Pharmacy and Pharmaceutical SciencesKwame Nkrumah University of Science and Technology Department of Herbal Medicine Faculty of Pharmacy and Pharmaceutical Sciences.Kwame Nkrumah University of Science and Technology

Objective:To establish the pharmacognostic characters for the correct identification and quality control of Hilleria latifolia(***),an important herb in Ghanaian folklore medicine,for the treatment of infections,pain and ***:The macro-morphological,qualitative and quantitative microscopic features,physicochemical and phytochemical features of the medicinally used parts of *** were evaluated using standard ***:The plant has simple,alternate leaves with entire *** lamina is ovate to broadly lanceolate with an acuminate *** is hypostomatic with anomocytie *** plant contains abundant prismatic crystals in all *** grains abound in the *** quantitative indices of the leaf and physicochemical parameters have also been ***:The pharmacognostic features established in this study may be used as part of the pharmacopoeia! standard for the correct identification and quality control of ***.

关键词： Hilleria latifolia Pharmacognostic features standardization Thin layer chromatography chromatogram Quantitative microscopy Fluorescence analysis

Protection effect of the anthraquinones, cassiatorin and aurantio-obtusin from seeds of Senna tora against cowpea weevil attack

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2018年第2期8卷 98-105页

作者： Valentine Chi Mbatchou Rita Akosua Dickson isaac Kingsley Amponsah Abraham Yeboah mensah Solomon Habtemariam Department of Applied Chemistry and Biochemistry University for Development Studies Navrongo Campus Department of Pharmacognosy Faculty of Pharmacy and Pharmaceutical Sciences Kwame Nkrumah University of Science and Technology Pharmacognosy Research Laboratories & Herbal Analysis Services UK University of Greenwich

Objetive: To explore the potential insecticidal, ovipositor deterrent and antifeedant effects of ethyl acetate extract of the seeds of Senna tora(Syn. Cassia tora) against cowpea weevil(Callosobruchus maculatus).Method: The activities were evaluated using standard *** these bioassays, the cowpea seeds were used directly as an insect feed. The activity of the extract and isolated compounds were tested at concentrations of 100, 200 and 300 μg/mL and compared to neem oil and cinnamaldehyde(as standard positive controls). Phytochemical analysis of the ethyl acetate extract was done through a number of chromatographic techniques and the structures of the isolated compounds were established through comprehensive spectroscopic analysis including 2 D-NMR and ESI-MS ***: Fractionation of the active ethyl acetate extract resulted in the isolation of one known anthraquinone,aurantio-obtusin(1) and a novel compound that was named as cassiatorin(2). Compounds1 and 2 showed comparable insect antifeedant properties with the positive controls while their insecticidal and ovipositor deterrent effects were far superior to the standard ***: It is thus concluded that Senna tora extracts and the isolated compounds(1 and2) may be employed in the postharvest management of stored cowpea seeds and as other crop protectants.

关键词： Senna tora Cassia tora Cassiatorin Aurantio-obtusin Insecticidal Ovipositor deterrent Antifeedant Cowpea weevil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

新能源高渗透率电力系统的频率响应

新能源高渗透率电力系统的频率响应

作者： isaac adjei Nketsiah 华北电力大学(北京)

学位级别：硕士

发电厂排放物是生产过程中重要的污染源。由于传统发电厂消耗大量化石燃料的同时产生大量污染,因此采用可再生清洁能源替代化石燃料是必要的。但是高渗透率可再生能源（RES）接入弱电网中,会威胁系统的整体稳定性和可靠性。由于大量使... 详细信息

发电厂排放物是生产过程中重要的污染源。由于传统发电厂消耗大量化石燃料的同时产生大量污染,因此采用可再生清洁能源替代化石燃料是必要的。但是高渗透率可再生能源（RES）接入弱电网中,会威胁系统的整体稳定性和可靠性。由于大量使用基于逆变器的电力电子设备,在转动惯量不存在或很小的情况下,系统阻尼特性和维持频率支撑等稳定性考虑更具挑战性。惯性不足对电网的稳定性构成了许多威胁,其中一个关键的问题是频率不稳定。频率稳定性受到系统惯性和频率储备的功率不平衡的不利影响,需要针对频率响应展开研究以确保频率稳定性。人们对于低惯量互联电力系统能够保留足够的PFR储备以响应可信事件并保持一定运行可靠性的能力表示非常关注。本工作旨在为电网发生突发事件后提供合适的解决方案。虚拟惯性由储能系统（ESS）提供,向电网提供大量惯性以确保稳定性。模糊逻辑控制器被用于观察VSC内的扰动。飞轮储能系统（FESS）被用于在突发事件后提供快速的频率响应。

关键词：可再生能源(RES) 储能系统(ESS) 模糊逻辑控制(FLC) 电压源变换器(VSC) 飞轮储能系统(FESS)

Effect of Switching Devices on Power Quality and Transient Voltage Suppression Using Capacitor Bank Model

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Journal of Power and Energy Engineering 2022年第5期10卷 77-89页

作者： isaac Kofi mensah Prah Joseph Cudjoe Attachie Electrical and Electronic Engineering Department University of Mines and Technology Tarkwa Ghana

The main purpose of the electrical power system is to transport and distribute energy generated by the central power plants in a safe and reliable manner to the customer premises. Most of the electrical equipment is exposed within the open which suggests they can be vulnerable to lightning strikes, road dwindling, windstorms, and a few engineering activities with the potential of causing different degrees of damage to the electrical equipment. One of the ways to guard the equipment is to deploy switching devices. However, the operations of most of these switching devices produce oscillatory transient in the electrical transmission and distribution systems which result in voltage, current, and frequency fluctuations in the load. This paper investigates the effect of switching devices on power quality and proposes a positive sequence voltage power transient suppression technique that can spontaneously improve the distorted voltage at the instant of capacitor switching using the capacitor line model as a case study. MATLAB/Simulink software was utilized for the analysis on an electrical network model with bus voltages of 69 kV/12.47 kV and 480 V. The results showed that, during switching operations, the positive sequence voltage power detector block produces ripple-free accurate results.

关键词： Capacitor Banks Inrush Current Laplace Transform Power Quality Posi-tive Sequence Switching Transient Voltage