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Experimental and Computational Study of the Microwave Absorption Properties of Recycled α-Fe2O3/OPEFB Fiber/PCL Multi-Layered Composites

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Journal of Materials Science and Chemical Engineering 2022年第3期10卷 30-41页

作者： ebenezer ekow mensah Raba’ah Syahidah Azis Zulkifly Abbas Department of Integrated Science Education Faculty of Science Education Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development Mampong Ashanti Ghana Department of Physics Faculty of Science Universiti Putra Malaysia Selangor Malaysia Institute of Advanced Materials Universiti Putra Malaysia Selangor Malaysia

The aim of this study was to fabricate multi-layered recycled α-Fe2O3/OPEFB fiber/PCL composites for microwave absorbing applications in the 1 - 4 GHz frequency range. The multi-layered composites were 6 mm thick and each consisted of a 2 mm thick layer of recycled α-Fe2O3/PCL composites at various loadings (5 wt% - 25 wt%) of 16.2 nm recycled α-Fe2O3 nanofiller, placed between two layers of 2 mm thick OPEFB fiber/PCL composites blended at a fixed ratio of 7:3. The real (ε') and imaginary (ε") components of the relative complex permittivity were measured using the open-ended coaxial probe technique and the values obtained were applied as inputs for the Finite Element Method to calculate the reflection coefficient magnitudes from which the reflection loss (RL) properties were determined. Both ε' and ε" increased linearly with recycled α-Fe2O3 nanofiller content and the values of ε' varied between 3.0 and 3.9 while the ε" values ranged between 0.26 and 0.64 within 1 - 4 GHz. The RL (dB) showed the most prominent values within the 1.38 - 1.46 GHz band with a minimum of -38 dB attained by the 25 wt% composite. Another batch of minimum values occurred in the 2.39 - 3.49 GHz range with the lowest of -25 dB at 2.8 GHz. The recycled α-Fe2O3/OPEFB fiber/PCL multi-layered composites are promising materials that can be engineered for solving noise problems in the 1 - 4 GHz range.

关键词： Multi-Layered Composites Recycled α-Fe2O3 Reflection Loss OPEFB Fiber Relative Complex Permittivity

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Causality Analysis on Export and Economic Growth Nexus in Ghana

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Open Journal of Statistics 2020年第5期10卷 872-888页

作者： Alice Constance mensah ebenezer Okyere Mathematics and Statistics Department Accra Technical University Accra Ghana ebenezer Okyere Research and Policy Banking Supervision Department Bank of Ghana Accra Ghana

The study examined the causal relationship between export and economic growth based on monthly data for the period 2010 to 2019. Composite Index Economic Activity (CIEA) was used as a proxy for real GDP (economic growth). Time series econometric techniques were employed to explore long-run and short run relationships as well as the causality between them. The results revealed the existence of long-run relationships;evidence of bi-directional causality and a rapid adjustment to equilibrium between real GDP and exports. Recommendations are that, policy makers should focus on implementing export oriented policies and promote economic growth to achieve sustainable development.

关键词： Export Economic Growth CIEA Econometric Techniques GDP

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The Impact of Colonial Rule on the Gyaman State

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History Research 2013年第6期3卷 389-405页

作者： Agyemang, Joseph Kwadwo Ofosu-mensah Ababio Emmanuel Gyamerah ebenezer Yaw University of Ghana Legon

The balkanisation of the African continent by the European powers in the nineteenth century caused the territorial division of people with the same ancestry into two or more states under different European governments. During the partition, the European powers did not take into consideration the cultural and historical boundaries of the people of Africa. In West Africa for example, the partition made some Nzema people to be found in La Cote d＇Ivoire and in Ghana. Some Dagarti are also found in Burkina Faso and while others remained in Ghana. Ewes today can be found in the three countries of Ghana, Togo and Benin. The same applies to the Bono in Gyaman. Some of the Gyaman people can be found in the Ivory Coast with others in Ghana. This article discusses Gyaman under the British and French colonial rule. It focuses on the responses of Gyaman authorities to colonialism and details out British and French colonial policies and their impact on the Gyaman people.

关键词： Gyaman British French colonial Ghana Cote d'Ivoire.

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Design Intervention: An Artistic Strategy (A Strategy) to Minimize Text Fading and Metal Commemorative Plaque Theft in Ghana

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Open Journal of Metal 2023年第1期13卷 1-17页

作者： Ansah-Asiedu Junior mensah Fiifi ebenezer Vicku Charles Samuel Nii Adamah Sampah Henrietta Meakoa Barfi-mensah Anita Akwaa Toffah Department of Industrial Art Ho Technical University Ho Ghana

The Commemorative Plaque Industry thrives at the hands of the local craftsmen in Ghana. Techniques, methods, tools, and materials used as handed to them by their previous masters have remained the same over the years. As a result, plaques produced had peculiar problems such as text fading, degrading the actual effect of the plaques. Additionally, metals once widely used for making plaques devoid of text fading in the industry seem to have lost their relevance due to metal plaque theft, rust on metal plaques, and the continuous rise in metal prices. This research uses descriptive, experimental, and case studies of the qualitative research method to examine the problems associated with locally produced commemorative plaques. A total of hundred (100) artisans, including metal scrap dealers, and plaque buyers, were selected for the study. Direct observation and face-to-face interviews were conducted with the local craftsmen, art lecturers and students, scrap dealers, and plaque buyers who were purposively sampled for the study. The study revealed that existing materials like ceramic and aluminium could be integrated innovatively to produce commemorative plaques devoid of text fading;a corrosion-resistant text could be made using anodized or coated metals used in smaller quantities to reduce costs while also making them unattractive for theft and lastly, silicone sealant was found to be a viable option for permanently inscribing text on porcelain bases. The results clarify and underline the necessity to grow the local plaque industry in terms of plaque production as another essential basis to assure high-quality plaques with no text fading that will survive for generations to serve their intended purpose.

关键词： Commemorative Plaques Strategy Porcelain Silicone Sealant Anodized Metal

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Investigation of Acoustomagnetoelectric Effect in Bandgap Graphene by the Boltzmann Transport Equation

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World Journal of Condensed Matter Physics 2024年第1期14卷 10-20页

作者： Raymond Edziah Samuel S. Bentsiefi Kwadwo Dompreh Anthony Twum Emmanuel Kofi Amewode Patrick mensah-Amoah ebenezer T. Tatchie Cynthia Jebuni-Adanu Samuel Y. mensah Department of Physics University of Cape Coast Cape Coast Ghana Department of Physics Education University of Education Winneba Ghana

We study the acoustomagnetoelectric (AME) effect in two-dimensional graphene with an energy bandgap using the semiclassical Boltzmann transport equation within the hypersound regime, (where represents the acoustic wavenumber and is the mean free path of the electron). The Boltzmann transport equation and other relevant equations were solved analytically to obtain an expression for the AME current density, consisting of longitudinal and Hall components. Our numerical results indicate that both components of the AME current densities display oscillatory behaviour. Furthermore, geometric resonances and Weiss oscillations were each defined using the relationship between the current density and Surface Acoustic Wave (SAW) frequency and the inverse of the applied magnetic field, respectively. Our results show that the AME current density of bandgap graphene, which can be controlled to suit a particular electronic device application, is smaller than that of (gapless) graphene and is therefore, more suited for nanophotonic device applications.

关键词： Boltzmann Transport Equation Acoustomagnetoelctric Effect Surface Acoustic Wave Gapless Graphene Weiss Oscillations

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Surgical Science 2019年第3期10卷 106-112页

作者： Alexander Oti Acheampong Merley Newman-Nartey Solomon Obiri-Yeboah Jonathan mensah Ama Amuasi Daniel Sabbah Jonathan Olesu Elijah ebenezer Asamoah Robert Nii Lamy Larmie Peter Donkor School of Medicine and Dentistry Kwame Nkrumah University of Science and Technology Kumasi Ghana School of Medicine and Dentistry University of Ghana Accra Ghana KomfoAnokye Teaching Hospital Kumasi Ghana

Background: Motorcycle related injuries have become a major public health problem because the increased use of motorcycles has been accompanied with a corresponding increase of road traffic accidents. Objective: The purpose of this study was to evaluate the occurrence of oral and maxillofacial injuries associated with motorcycles as seen at the second largest Teaching Hospital in Ghana, the Komfo Anokye Teaching Hospital (KATH). Method and Materials: The compiled data that were reviewed for this retrospective study were obtained from the Accident and Emergency unit of KATH. These comprised 135 successive maxillofacial trauma patient records entered from August 2017 to August 2018. Results: Total number of road traffic related injuries seen at OMFS was 135 during the study period. Out of this number, 66 were related to motorcycle injuries. This represented 48.7% of the Road Traffic Accidents seen at oral and maxillofacial surgery department (OMFS). The age range was from 3 to 64 years. The average age was 26.7 years. 62 (93.9%) were males and 4 (6.1%) were females. 16 (24.2%) of the motorcycle injuries were caused by the “Okada”, 2 (3.0%) by “Pragia” and 48 (72.8%) by the “Aboboyaa”. 46 (69.7%) of the motorcycles victims were themselves the riders, 12 (18.2%) were pedestrians and 8 (12.1%) were passengers. There were 8 deaths. 6 (75.0%) of the deaths were caused by the “Aboboyaa”. “Okada” accounted for only 2 (15.0%) deaths. Concerning the riders and the passengers, only 8 (14.8%) of the victims were helmeted. The majority were unhelmeted (85.2%). Conclusion: Motorcycle transportation is the cause of many oral and maxillofacial injuries. Majority of the victims suffered multiple facial bone fractures. Males were more often affected than females and the majority were unhelmeted.

关键词： Motorcycle Oral Maxillofacial Injuries Kumasi

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Management System Activities of the Operation and Utilization of GHARR-1

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World Journal of Engineering and Technology 2023年第4期11卷 807-826页

作者： Edward Shitsi Henry Cecil Odoi Kwame Gyamfi Philip Dordoh-Gasu Isaac Kwasi Baidoo Edward Oscar Amponsah-Abu Emmanuel Kwesi Boafo Samuel Yao Ganyaglo Samuel Boakye Dampare Henry Kwame Obeng William Osei-mensah Wilfred Sedofia Massiasta Robert ekow Quagraine Nuclear Reactors Research Centre National Nuclear Research Institute Ghana Atomic Energy Commission Accra Ghana

The Ghana Research Reactor-1 (GHARR-1) is a 34 kW low enriched uranium (LEU) Miniature Neutron Source Reactor (MNSR), tank-in-pool type and cooled by natural circulation under atmospheric pressure operating conditions. GHARR-1 is owned by Ghana Atomic Energy Commission (GAEC) and operated by National Nuclear Research Institute (NNRI), one of the institutes of GAEC. GHARR-1 is housed by Nuclear Reactors Research Centre (NRRC), one of the Centres of NNRI. Management/Administration, Radiation protection, Reactor operation and maintenance, Reactor utilization and Physical protection are the various systems/units that integrate to manage the activities of operation and utilization of GHARR-1 in addition to the quality assurance and quality control management system of the research reactor facility. The GHARR-1 which is currently in operation follows a robust maintenance culture adopted by the management system and this has made it possible to keep the reactor in operation with minimal interruption. The management system activities adopted at the Centre to ensure safety of the workers, public and the research reactor facility include authorization of the operation of the reactor for any experiments/modifications;providing material and financial resources for maintaining the research reactor facility;following standard procedures while carrying out Neutron Activation Analysis;participation in IAEA proficiency test;irradiation sites/positions characterization;following standard procedures while carrying out reactor operation and maintenance including reactor and pool water purification and other related activities;monitoring radiation levels in the controlled, supervised and uncontrolled areas of the research reactor facility as well as during reactor operation and maintenance;controlling the physical entry of the workers and public into the research reactor facility;and ensuring that the security structures provided to protect the reactor facility are functioning properly.

关键词： Management Systems Quality Assurance and Quality Control Research Re-actor Operation and Utilization Monitoring Forms Ghana Research Reactor-1 (GHARR-1)

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