Possibilities And Challenges Of Radio Frequency Energy Harvesting In Dar Es Salaam, Tanzania,
2020
Department of Electronics & Telecommunications Engineering, University of Dar es Salaam
Possibilities And Challenges Of Radio Frequency Energy Harvesting In Dar Es Salaam, Tanzania, Fredrick Isingo
Tanzania Journal of Engineering and Technology (TJET)
This paper presents investigation on the possibilities and challenges of harvesting ambient Radio Frequency Energy (RFE) at Dar es Salaam region in Tanzania. The Radio Frequency (RF) signals were measured using a Rohde and Schwarz FSC 3 spectrum analyzer observing available frequencies with their respective power. Among several RF signals received, the most powerful signals observed were; 800 MHz, 950 MHz, 2100 MHz and 2400 MHz, having average signal strengths of about-30.29 dBm,-35.94 dBm,-42.90 dBm and-30.42 dBm respectively. The power possessed within these frequencies were suitable to be harvested due to their signal strengths, an overall power average of-34.89dBm was …
User-Centred Scalable Big Data Visualizer For Power Consumption Data In The Electrical Secondary Distribution Network,
2020
Department of Computer Science and Engineering, University of Dar es Salaam
User-Centred Scalable Big Data Visualizer For Power Consumption Data In The Electrical Secondary Distribution Network, Ellen Kalinga
Tanzania Journal of Engineering and Technology (TJET)
Establishment of Smart Grids for electrical power has been practised worldwide for the purpose of bringing reliability, security, and efficient management of electrical power networks for enhancing quality service to the society. Apart from the potential aim, smart grid has been a challenge to developing countries, including Tanzania from cost and technology point of view. Due to the use of many smart equipment involved in smart grids like Advanced Metering Infrastructure (AMI) equipped with smart meters and sensors, handling and managing big data has been a challenge. Among the challenges is the issue of visualizing the Big Data due to …
Deconvolution Of Mono-Energetic And Multi-Lines Gamma-Ray Spectra Obtained With Nai(Tl) Scintillation Detectors Using Direct Matrix Inversion Method,
2020
University of Dar es salaam
Deconvolution Of Mono-Energetic And Multi-Lines Gamma-Ray Spectra Obtained With Nai(Tl) Scintillation Detectors Using Direct Matrix Inversion Method, Mwingereza John Kumwenda Dr
Tanzania Journal of Engineering and Technology (TJET)
Performance of a NaI(Tl) scintillation detector based on the gamma-ray spectroscopy system is not satisfactory in retaining its original peak (which is delta like function) of various gamma ray spectrum. The method of achieving precise peak for the various gamma ray was conducted by converting the observed pulse-height distribution of the NaI(Tl) detector to a true photon spectrum. This method is obtained experimentally with the help of an inverse matrix deconvolution method. The method is based on response matrix generated by the Monte Carlo simulation based on Geant4 package of mono-energy gamma-ray photon ranging from 0.050 to 2.04 MeV in …
Assessment Of The Performance Of Grinding Circuit For Buzwagi Gold Mine,
2020
University of Dar es Salaam, School of Mines and Geosciences, Department of Mining and Mineral Processing Engineering, P.O. Box 35131, Dar es Salaam, Tanzania
Assessment Of The Performance Of Grinding Circuit For Buzwagi Gold Mine, Alphonce Wikedzi
Tanzania Journal of Engineering and Technology (TJET)
It had been reported by the management of Buzwagi Gold Mine (BGM) that grinding circuit was designed to produce final product size of 125 μm, which had not been achieved for a long period of time under both, low to normal (i.e. 450-600 t/h) and high (i.e. > 650 t/h) throughputs. Also, the performance behaviour of the circuit had not been reviewed after long time of operation. Hence, an evaluation study was conducted in order to recommend improvement in mine operations. The study was realized through three circuit survey campaigns and laboratory experimentations. From the surveys, size distributions and solids contents …
Fermentability Of Concentrated Sulfuric Acid Hydrolyzates From Aspenwood And Pinewood,
2020
Department of Chemical and Mining Engineering, University of Dar es Salaam
Fermentability Of Concentrated Sulfuric Acid Hydrolyzates From Aspenwood And Pinewood, Kando Janga
Tanzania Journal of Engineering and Technology (TJET)
The fermentability of hydrolyzates derived from two-stage concentrated sulfuric acid hydrolysis of Trembling aspen (Populus tremula) and Scots pine (Pinus sylvestris) were investigated. Three types of hydrolyzates were produced at mild, moderate and high decrystallization severity conditions. Portions of each of the original hydrolyzates were concentrated by vacuum evaporation to increase the sugar fraction to simulate industrial applications. Both sets of hydrolyzates were fermented anaerobically using Saccharomyces cerevisiae ATCC 96581. After 23 hours of fermentation, complete glucose consumption was observed for all the original hydrolyzates, with no signs of inhibition. The ethanol yields from these hydrolyzates ranged from 68% to …
Analysis Of Performance Characteristics Predicted From Several Experimental Data And Conversion Methods For Pumps As Turbine Application Using Statistical Techniques,
2020
Department of Energy and Petroleum Engineering, University of Dodoma, P. O. Box 259, Dodoma, Tanzania.
Analysis Of Performance Characteristics Predicted From Several Experimental Data And Conversion Methods For Pumps As Turbine Application Using Statistical Techniques, Ombeni J. Mdee
Tanzania Journal of Engineering and Technology (TJET)
Different performance characteristics have been indicated when running centrifugal pumps in the reverse direction. The water flows from the discharge side of the pump to the suction side to run in the reverse direction and generate the mechanical rotational energy for the micro-hydropower plant. The current study evaluates the extent of variation of performance characteristics predicted by several experimental data from different pump-specific speeds and conversion methods. The performance characteristics discussed include the head, flow rate, efficiency and specific speed. The flow rate and head of a pump operating in pump mode divided with the characteristic of the pump operating …
Bibliometric Review Of Mppt Algorithms For Wind Energy Conversion Systems,
2020
Symbiosis Institute of Technology,Symbiosis International Deemed University, Pune, India
Bibliometric Review Of Mppt Algorithms For Wind Energy Conversion Systems, Jayshree Ashok Pande, Paresh Nasikkar
Library Philosophy and Practice (e-journal)
The existing conventional fuels are going up in prices and going down in availability. This has boosted the demand for renewable resources like wind energy. Wind energy being abundantly available is becoming very popular as it is a freely available pollution-free green energy. Some technical aspects like the tracking of maximum power from the wind energy conversion systems have a very high impact on the efficiency of the wind energy conversion systems. Several algorithms have been implemented for tracking the maximum power point of the wind energy conversion systems. The main objective of this paper is to study the extent …
Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling,
2020
1. Faculty of Civil Engineering and Mechanics, Jiangsu University, Zhenjiang 212013, China;2. Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China;
Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling, Cheng-Rong Yu, Jian-Guo Zhu, Cong-Ying Jiang, Yu-Chen Gu, Ye-Xin Zhou, Zhuo-Bin Li, Rong-Min Wu, Zheng Zhong, Wan-Bing Guan
Journal of Electrochemistry
Solid oxide fuel cell (SOFC) is a high-efficient clean conversion device for future energy management. Because of the low antioxidant reduction ability and complex thermal stress, the structure of traditional asymmetrical thin anode-supported planar SOFC is easily to be broken under stack operating conditions. To overcome these defects, a new complete symmetrical SOFC based on double-sided cathodes was developed. To study the influences of gas flow direction and current collection mode on the cell performance inside stack, a numerical model was established by finite element method based on the theory of electro-thermo-chemo multiphysical coupling. By applying this model, the molar …
Effect Of Stereotaxically-Constructed Graphene On The Negative Electrode Performance Of Lead-Acid Batteries,
2020
Collaborative Innovation Center of Sustainable Energy Materials, Guangxi University,Nanning 530004, Guangxi, China;
Effect Of Stereotaxically-Constructed Graphene On The Negative Electrode Performance Of Lead-Acid Batteries, Pin-Song Chen, Yi-Tao Hu, Xin-Yi Zhang, Pei-Kang Shen
Journal of Electrochemistry
With the advantages of high ratio surface area, excellent conductivity and high stability, the stereotaxically-constructed graphene (SCG) material was added to the negative active material (NAM) of lead-acid battery for improving battery performance. XRD, SEM and cyclic voltammetry tests were carried out to analyze the influence of SCG on negative active material. It is found that the conversion efficiency of lead sulfate to lead in the negative active material added with SCG material was higher than that of control group, and the particle size of the lead sulfate obtained after the discharge reaction was smaller, which are favorable factors for …
Preparations And Photoelectrochemical Performances Of Rgo-Tio2 Nanotubes Arrays,
2020
1. State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Preparations And Photoelectrochemical Performances Of Rgo-Tio2 Nanotubes Arrays, Ze-Yang Zhang, Lan Sun, Chang-Jian Lin
Journal of Electrochemistry
Decorating TiO2 nanotube arrays with RGO to improve the photocatalytic activity of TiO2 nanotube arrays has been reported. For the reported RGO-TiO2 nanotube arrays, TiO2 nanotube arrays were prepared by anodizing the high-purity Ti foil in an organic electrolyte for multiple-step treatments, while RGO were deposited on TiO2 nanotube arrays by using cyclic voltammetry or other electrical reduction methods. To enhance the reduction degree and the coverage of RGO on the resultant RGO-TiO2 nanotube arrays, in this work, the one-step electrochemical anodization in hydrofluoric acid was used to fabricate TiO2 nanotube arrays with …
Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction,
2020
1. CAS Key Laboratory of Low-carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China;2. University of Chinese Academy of Sciences, Beijing, 100049, China;
Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction, Chang Zhu, Wei Chen, Yan-Fang Song, Xiao Dong, Gui-Hua Li, Wei Wei, Yu-Han Sun
Journal of Electrochemistry
Electrochemical conversion of carbon dioxide (CO2) driven by renewable electricity that can meet both carbon emission reduction and renewable energy utilization has been rapidly developed in recent years. Copper (Cu) catalyst has long been a promising candidate for CO2 electroreduction applications because of its natural abundance and specific capability of producing a substantial amount of C2 products. However, various metallic Cu electrodes reported have been significantly influenced by the adsorption of certain cation/anion ions, resulting in wide-span catalytic activities and selectivity for various products. In addition, a recent report demonstrated that by virtue of gas-diffusion flow cell …
Preparation And Process Optimization Of Cathode Materials For Lithium-Sulfur Batteries,
2020
Ningde Contemporary Amperex Technology Co., Ltd, Ningde Fujian 352106, China;
Preparation And Process Optimization Of Cathode Materials For Lithium-Sulfur Batteries, Kai Wu
Journal of Electrochemistry
Lithium-sulfur (Li-S) batteries represent promising candidates for next-generation energy storage system due to their high energy density and low material cost. However, the industrial application of Li-S batteries remains challenges because of the shuttle effect from lithium polysulfides and the lack of facial routes for Li-S battery preparation. To solve these problems, a cathode consisting of different commercial carbon materials, namely, acetylene black (SP), Ketjen Black (KB) and carbon nanotube (CNT), with sulfur (S) is prepared separately for Li-S battery. After the process of 8-h ball milling for KB/S composite, together with the polyvinyl pyrrolidone (PVP) binder, the cathode could …
Step-By-Step Modification Of Graphite Felt Electrode For Vanadium Redox Flow Battery,
2020
School of Environmental and Material Engineering, Yantai University, Yantai 264000, Shandong, China;
Step-By-Step Modification Of Graphite Felt Electrode For Vanadium Redox Flow Battery, Jing-Yuan Lou, Dong-Jiang You, Xue-Jing Li
Journal of Electrochemistry
As a well-known electrode material of the vanadium redox flow battery (VRFB),graphite felt electrode is the frequently-used electrode material in VRFB, and its low electrochemical activity is one of the key factors for the low power density of VRFB. In this work, we proposed a step-by-step modification method, which used KMnO4 to oxidize graphite felt first and then placed in an activation solution to excite its reactivity, to improve the electrochemical performance of the graphite felt electrode. According to the results from cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) characterizations …
Degradation And Thermal Characteristics Of Lini0.8Co0.15Al0.05O2/Graphite Lithium Ion Battery After Different State Of Charge Ranges Cycling,
2020
1. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China;
Degradation And Thermal Characteristics Of Lini0.8Co0.15Al0.05O2/Graphite Lithium Ion Battery After Different State Of Charge Ranges Cycling, Cun Wang, Wei-Jiang Zhang, Teng-Fei He, Bo Lei, You-Jie Shi, Yao-Dong Zheng, Wei-Lin Luo, Fang-Ming Jiang
Journal of Electrochemistry
The LiNi0.8Co0.15Al0.05O2 (NCA) cathode exhibits high energy density and large reversible capacity, which plays an essential role in the field of electric vehicles (EVs). However, low capacity retention and poor thermal stability limit its application. Few literatures are found for the capacity degradation mechanism of NCA/graphite batteries at home and abroad. The different state of charge (SOC) ranges cycle degradation behaviors of 18650-type NCA/graphite (2.4 Ah) battery were studied in this paper. The SOC ranges considered were 0% ~ 20% (low), 20% ~ 70% (medium), 70% ~ 100% (high), and 0% ~ 100% …
Preparations And Sodium Storage Properties Of Ni3S2@Cnt Composite,
2020
School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050;
Preparations And Sodium Storage Properties Of Ni3S2@Cnt Composite, Ming-Tao Duan, Yan-Shuang Meng, Hong-Shuai Zhang
Journal of Electrochemistry
Transition metal sulfides (TMSs)-based electrode materials with highly reversible sodium storage have attracted extensive attentions as one of the most prospective electrode materials for sodium ion batteries (SIBs). However, low cycling stability and rate property caused by large volume expansion and poor electronic conductivity during the electrochemical reaction still hamper their further practical application. In this work, in-situ encapsulated Ni3S2 nanoparticles in carbon nanotubes (Ni3S2@CNT) have been successfully fabricated as an anode material for high-performance SIBs by a one-step solid-phase calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), …
Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction,
2020
State Key Laboratory of Fine Chemicals, School of Chemical Engineering,Dalian University of Technology, Dalian 116024, Liaoning, China;
Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song
Journal of Electrochemistry
Water electrolysis for hydrogen production is beneficial for solving the problem of energy crisis and environmental issues. It is necessary to study highly active and cost-effective catalysts toward hydrogen evolution reaction (HER) to reduce the consumption of noble metals. Herein, we report the synthesis of core-shell structured Ru@Pt0.24Ru nanoflowers electrocatalyst by stepwise reduction of Ru and Pt precursors in the mixture of oleylamine and benzyl alcohol at 160 oC. The average diameter of the resultant Ru@Pt0.24Ru was 16.5±4.0 nm with a bulk atomic ratio between Pt and Ru of 0.24:1 and a surface ratio of …
Solar Photovoltaic Performance Monitoring: A Bibliometric Review, Research Gaps And Opportunities,
2020
Symbiosis International (Deemed University), Pune
Solar Photovoltaic Performance Monitoring: A Bibliometric Review, Research Gaps And Opportunities, Javed Sayyad, Paresh Nasikkar
Library Philosophy and Practice (e-journal)
Electrical power generation has been revolutionized by growing demand and use of Renewable Energy (RE) sources such as Solar Photovoltaic (SPV) as the main electricity source in modern times. The main objective of this bibliometric analysis is to understand the scope of the literature available for SPV performance characterization. This detailed reviewed was performed on the documents related to SPV research considering all the subject categories from Scopus and Web of Science (WoS) databases. The patterns for the particular set of keywords were broke down with the recuperated outcomes from Scopus database in the language, publication type, year of publication, …
Improving The Maximum Power Point Tracking Efficiency Of Photovoltaic Arrays Via Machine Learning And Deep Learning,
2020
Kennesaw State University
Improving The Maximum Power Point Tracking Efficiency Of Photovoltaic Arrays Via Machine Learning And Deep Learning, Sumedha Inamdar
Master of Science in Computer Science Theses
Under partial shading conditions, photovoltaic (PV) modules in a solar array experience varying irradiance. A Global Maximum (GM) and multiple Local Maximums (LMs) can originate on the Power-Voltage (P-V) curve under nonuniform irradiance conditions. There are many maximum power point tracking (MPPT) algorithms developed to detect the true maximum power point (MPP) of a PV array. However, in the real-world environment, limited samples of power-voltage (P-V) data might be available to quickly and accurately predict the position of the global maximum point. Since the change of environmental conditions are dynamic, limited time is available to locate the global peak. Machine …
Multigrid For The Nonlinear Power Flow Equations,
2020
Southern Methodist University
Multigrid For The Nonlinear Power Flow Equations, Enrique Pereira Batista
Mathematics Theses and Dissertations
The continuously changing structure of power systems and the inclusion of renewable
energy sources are leading to changes in the dynamics of modern power grid,
which have brought renewed attention to the solution of the AC power flow equations.
In particular, development of fast and robust solvers for the power flow problem
continues to be actively investigated. A novel multigrid technique for coarse-graining
dynamic power grid models has been developed recently. This technique uses an
algebraic multigrid (AMG) coarsening strategy applied to the weighted
graph Laplacian that arises from the power network's topology for the construction
of coarse-grain approximations to …
Circuit Topology Estimation In An Adaptive Protection Platform,
2020
University of New Mexico
Circuit Topology Estimation In An Adaptive Protection Platform, Daniel Ruiz
Electrical and Computer Engineering ETDs
Modern electric power systems, power system protections and controls have experienced a significant change, thanks to the introduction of new technologies, such as microprocessors, GPS, communication, etc. These technologies brought an increased amount of measured-data and information flow on power grids. Adaptive protection systems have been introduced to increase the reliability, selectivity, and sensitivity of the traditional protection systems. An adaptive protection system highly relies on the communication system infrastructure to identify the latest status of power grid (e.g., circuit topology or generation level of distributed energy resources). However, when the communication links to some of the equipment are outaged …
