Methods to Determine the Overall Health and Condition of Large Power Transformers

The unsteady implementation of the conceptual model of deregulation of electric utility industry in many countries has caused significant consequences in the overall health of the general population of large power transformers [LPTs]. LPTs are now subject to adverse conditions due to advanced aging, decreases in routine testing and maintenance activities, reduction of capital for repair and replacement, increased loading and lack of technical expertise. The method presented in this paper provides a blueprint to successfully determine the overall health and condition of LPTs. Keywords: Transformers, gas-in-oil, diagnostics, leakage reactance, maintenance

Multichannel Distribution Meter: A Veritable Solution in Power Distribution and Theft Prevention in Congested Environments

Power theft in partitioned commercial apartments, especially in the form of unpaid bills due to disputes, is a major challenge to revenue recovery in the power sector. This paper presents a multi-channel power distribution metering solution that serves to resolve disputes among users in partitioned apartments, and between the power distribution company and the end users of electricity. Partitioned apartments in commercial buildings particularly in congested environments shares energy supply meters among several users. This often leads to disputes and results to power theft in the form of unpaid bills and meter tampering. This paper described how power from a single supply meter can be adequately shared among a number of users with dispute arbitration. Each user’s channel is fed, monitored and controlled from a central unit which calculate and display energy usage, per unit cost and amount in cash consumed per channel. Compliant/non-compliant channel are connected/disconnected through a remote wireless access. It is envisaged that the use of this method for electricity distribution in commercial apartments, will greatly reduce power theft and increase revenue generation for the power industry. It will also eliminate disputes and possible litigations for the power industry and among users.http://dx.doi.org/10.4314/njt.v34i4.2

The effect of ascorbic acid and propranolol on normal sleep and open field locomotor activity in wistar rats

Background: Knowledge about the actual central nervous system properties of propranolol or ascorbic acid remains poorly understood. Information on the neural mechanism of the interactions of these compounds in the central nervous system is still very hazy and presently a subject riddled with speculations. This study was designed to investigate the possible effects of ascorbic acid on open field locomotor activity and normal sleep in healthy adult rats and evaluate how these correlate with those of propranolol. MethodS: Eighty healthy adult Wistar rats of both sexes were divided into two groups of 40 animals each group. One group received ascorbic acid treatment while the other group received propranolol, both of which were prepared into different doses, respectively. Each of the various doses of these compounds was administered separately for a period of 21 days in each experimental group, while the control animals received 0.3ml normal saline for the same period. The results were subjected to statistical analysis, using MicroCal Origin Statistical Software version 8.0, and the Student’s T- test to compare the results and P values of  ≤ 0.05) were regarded as statistically significant. Results: Behavioral activation with increased locomotor activity and wakefulness were observed in doses of ascorbic acid while the animals appeared behaviorally-sedated with clear sleep promoting effects in the wistar rats in doses of propranolol. Conclusion: It is possible from present results that dopaminergic and cholinergic neural mechanisms account for the gross behavioral activation rats. It is clearly suggestive that the modulating influence on slee

The Modeling and Dynamic Characteristics of a Variable Speed Wind Turbine

In this paper, a functional structure of a wind energy conversion system is introduced, before making a comparison between the two typical wind turbine operating schemes in operation, namely constant-speed wind turbine and variable-speed wind turbine. In addition, the modeling and dynamic behavior of a variable speed wind turbine with pitch control capability is explained in detail and the turbine performance curves are simulated in the MATLAB/simulink. Keywords: Drives, energy conversion, modeling, power systems, turbines, wind energy, velocity control

Oil spill identification in visible sensor imaging using automated cross correlation with crude oil image filters

An algorithm for detection of crude oil spills in visible light images has been developed and tested on 50 documented crude oil spill images from Shell Petroleum Development Company (SPDC) Nigeria. A set of three 25 x 25 pixels crude oil filters, with unique red, green, and blue (RGB) colour values, homogeneity, and power spectrum density (PSD) features were cross-correlated with the documented spill images. The final crude oil spill Region of Interest (ROI) was determined by grouping interconnected pixels based on their proximity, and only selecting ROIs with an area greater than 5,000 pixels. The crude oil filter cross correlation algorithm demonstrated a sensitivity of 84% with a False Positive per Image (FPI) of 0.82. Future work includes volume estimation of detected spills using crude oil filters, and utilizing this information in the recommendation of appropriate spill clean-up and remediation procedures for the detected spills. Keywords: Crude Oil Spill Detection, Crude oil image filters, Cross correlation, Visible sensor imaging, Oil Spill Segmentation

LED Light a futuristic Technology for African Rural Electrification

This paper considers the concept of very advanced technologies being developed in the West, to solve rural electrification problems in the developing world. The myth that poor quality is cheaper and therefore more affordable for rural electrification is dispelled. On the contrary this paper points to instances when problems of the rural poor have been solved by using cutting edge technologies where standard solutions had proved unworkable. In this paper a futuristic technology, the white light emitting diode (LED), for general lighting, is examined as a solution to African rural electrification. Comparisons are made with conventional technologies. Keywords: Lumen, efficacy, incandescent, lifespan, lighting, lamp, illuminance, modeled

Optimizing the Output Current for a DC-DC Converter

Portable product design requires that power supply circuits use as little space as possible on the PC board, so highly integrated DC-DC converter devices are generally preferred. System designers need to understand the maximum amount of power that can be delivered by a given integrated circuit solution. Total output power capability is not only a function of the power converter IC, but also dependent on external components and operating frequency. This paper explores the relationship between a power converter’s rated switch current and its effective load current capability for two common DC-DC converter topologies, the non-isolated buck and boost circuits. By proper selection of external components and operating frequency, it is possible to maximize the output current available from a given power conversion device. Keywords: Converters, switching frequency, buck, boost, inductor, components, switch, current

Solar Hydrogen Fuel Cell Technology, Principle, Applications and Market

This paper is designed to provide “The Principle of operation of Solar Hydrogen Energy System” and “Explanation of the Components” and describes “The interaction of the components in detail”. Also, it describes its applications and future market. Keywords: Hydrogen gas, electrolyzer, oxygen gas, electrodes, proton exchange membrane, fuel cell

Abstractive multi-document summarization - paraphrasing and compressing with neural networks

This thesis presents studies in neural text summarization for single and multiple documents.The focus is on using sentence paraphrasing and compression for generating fluent summaries, especially in multi-document summarization where there is data paucity. A novel solution is to use transfer-learning from downstream tasks with an abundance of data. For this purpose, we pre-train three models for each of extractive summarization, paraphrase generation and sentence compression. We find that summarization datasets – CNN/DM and NEWSROOM – contain a number of noisy samples. Hence, we present a method for automatically filtering out this noise. We combine the representational power of the GRU-RNN and TRANSFORMER encoders in our paraphrase generation model. In training our sentence compression model, we investigate the impact of using different early-stopping criteria, such as embedding-based cosine similarity and F1. We utilize the pre-trained models (ours, GPT2 and T5) in different settings for single and multi-document summarization.SGS Tuition Award Alberta Innovates Technology Futures (AITF