Evaluation of the steady state performance of a squirrel cage induction motor using per-phase equivalent circuit

The performance evaluation of cage induction motor continues to receive tremendous attention because of its vital effect on the overall system stability. The model has predicted the behavior of cage induction motor under different operating conditions and in selecting the appropriate motor for a specific load application. There is often a challenge when a squirrel cage induction motor is connected to a time-varying load, particularly when the motor is selected without considering the effects of pulsating torques. The usual method used for steady state analysis of induction motors is the equivalent circuit method. Using the per phase equivalent circuit of the induction motor, stator current and referred rotor current were computed using simple circuit analysis. Once the currents are available, then power can be computed because the voltage is already known.

Analysis of different impact rates on the forecasts cost of building project using sensitivity analysis techniques

Over the years, Life Cycle Costing (LCC) has been recognized and used as an important technique for evaluating, forecasting and discounting the future costs of building to the present day value, from conception, design to completion, operation, maintenance, down to decommissioning. This work presents a study of Analysis on different discount rate of the forecasts cost of building project using sensitivity analysis techniques, the case study being Calabar International Conference Center (CICC) building project. Life cycle cost analysis was conducted and forecast for 51 years using Net present value (NPV) with the following discount rates 4%, 5%, 6%, 8%, 10%, 12% and 13% respectively. Results showed that the lower the discount rates, the higher the cost value and via vasa. The building had a positive value >0 indicating a significant benefit at the end of the study period. The percentage contribution of the discount rate on the initial cost, salvage value and the life cycle cost indicates that at 4% the initial cost accounted for 85% of the discounted cost, life cycle cost 13% and salvage value 2%. The salvage value recorded 0% at 12% and 13% discount rate The higher the discount rates the higher the discounted initial cost and the lower the life cycle cost.

Identification and classification of barriers and benefits of requirements traceability in project development

Requirements are conditions that a product, service, or process must present and requirements management facilitates this realization. For this, the requirements traceability technique is used for the development of projects and systems and all management of the requirements life cycle. However, the literature recognizes the proven benefits of adherence to the technique, but the plurality of problems inhibits its adherence. Thus, this article aims to identify and classify the barriers and benefits of requirements traceability. For this purpose, it was elaborated a systematic literature review, and for the results´ analysis and codification, the MAXQDA software was used. A total of 15 barriers and 15 benefits were identified. It is possible to verify that both in the case of benefits and barriers, there is a cause and effect relationship between them. In other words, barriers such as “Low flexibility and integration of tools” lead to the emergence of other barriers such as “Management inefficiency”.

Performance evaluation of polycrystalline photovoltaic modules in a Guinea Savanna and Mangrove swamp

This central idea of this research is to investigate how voltage, current, power output and efficiency of polycrystalline photovoltaic (PV) modules installed in a Guinea Savanna and Mangrove Swamp is affected by temperature, relative humidity and irradiance. The study locations are Calabar (mangrove swamp) and Ogoja (guinea savanna), in Cross River State, Nigeria. Two polycrystalline PV modules of exact specification mounted on a platform one-metre-high above the ground were used. A digital solar power meter (SM206) and a digital solar flux meter (MS 6616) was used to monitor and measure solar power and solar flux reaching the PV modules. A digital hygrometer and thermometer (KT-908) were used to monitor and measure the relative humidity and ambient temperature level at the height of installation and a digital multimeter (M880C+) accompanied with a temperature sensor was used to monitor voltage, current and panel temperature values from the modules. Analysis of the collected data reveals that the efficiency of the modules were not constant throughout the day. However, a higher voltage production and efficiency level was obtained for the PV module installed in Ogoja than that installed in Calabar under their respective levels of relative humidity, temperature and irradiance.

Evaluation of the effects of electrical power outages on small and medium scale enterprises (SMEs)

This study evaluated the effects of electrical power outages on Small and Medium Scale Enterprises (SMEs). The study was guided by two specific objectives of determining the cost of alternative sources of power supply and its impact on the profitability of businesses of selected SMEs in Elelenwo community in Obio/Akpor Local Government of Rivers State and to suggest possible ways of reducing the power outages in Elelenwo Community. The costs of power supply using private power generation and that of public power generation from Port Harcourt Electricity Distribution (PHED) were collected from selected SMEs in the study area. Findings established the fact that electrical power outages have significant negative effects on the businesses of small and medium scale enterprises (SMEs) which in turns affect their profitability and sustainability. This was established by finding the correlations of the costs of running businesses with private power generation and that of using public power generation for selected SMEs and the results yielded negative correlation coefficients. The study also suggested possible ways of reducing the power outages.

Assessment of adoption potential for smallholder conservation agriculture in Pandamatenga vertisols of northern Botswana

The adoption of conservation agriculture among small-scale farmers is still low despite the proven economic and environmental benefits of the technology. This study was conducted at Pandamatenga of Chobe District in northern Botswana. The main aim of the study was to determine the factors that influence the adoption of Conservation Agriculture (CA) in the study area. A structured questionnaire was used for the collection of the socio- economic and demographic characteristics of the sampled smallholder rainfed farmers. The socio - economic characteristics of the smallholder rainfed farmers included land holding size (ha), labour availability, livestock possession, education level, and farming experience. Demographic characteristics considered in the study included smallholder rainfed farmers’ age, marital status, gender, and average number of family members in the household. Data was analysed using descriptive statistics and the logistic regression model. The results have shown that gender and farm size had a significant influence on smallholder rainfed farmers’ decision to adopt CA technologies in Pandamatenga. Smallholder rainfed farmers had a positive perception and a high level of acceptance of CA technologies that were tried in their area.

Improving the quality of superphosphate fertilizer resulting from the use of low-quality phosphate rock

The aim of this paper is to improve the quality of superphosphate fertilizer resulting from the use of low quality phosphate rock by the use of additives as Illite clay, The use of Glauconite rock (green sand) and illite rock (green clay) in the abu tartur phosphate's region – new valley and mixing it with low quality phosphate rock (22%) for the production of fertilizers with higher quality and rich with the essential elements for plants (N, K) which aren't exist in low quality phosphate rock individually, an industrial sample test had been done and a mixed fertilizer had been produced (Elayte rock and low quality phosphate (22% ) as 1:1).

PLS-SEM a 2nd generation technique: Concepts, properties characteristics and phases for its application

The multivariate technique of partial least squares structural equations (PLS-SEM) considered as second generation, has become more relevant in its application in recent years in various investigations, so this article considers an descriptive research, the which presents some properties characteristic of said technique and through the application of data and values obtained from a case study shows the phases required to validate and evaluate a model with the PLS-SEM technique. With the results obtained, a theoretical model is generated and proposed that could be useful for researchers who starting in the use and application of this technique.

Rice husk as sustainable waste energy for small farmers - A review

A review of rice husks as an energy source was carried out to provide information on their use in the drying process, especially handling post-harvest for small farmers. This is done because there are still many small farmers who only use the sun to dry their food. Drying is done by dry in the sun and this process still has drawbacks. The weakness of the process of drying in the sun is very dependent on the weather, so when it is cloudy or rainy the drying process will stop. Of course, this causes losses to small farmers, on the other hand, waste is abundant in the form of rice husks. This is related to rice as the farmer's staple crop and rice husk is a by-product of rice production. Based on several studies and libraries, a satisfactory result was obtained regarding rice husks. Rice husk can be used as sustainable alternative energy. Increasing the drying temperature, it can be done through an energy conversion process. This method is carried out by adding a heat exchanger to increase heat transfer from the burning of rice husks to the drying air. This method is also able to shorten the drying time and the dried food becomes hygienic. This is as a result of the drying process of foodstuffs carried out in the drying room, to avoid dirt and dust. Utilization of rice husks and heat exchangers as an alternative in overcoming the problems of conventional agriculture in terms of uncertain weather and climate.

Establishment of transition point in operating mode for Constant Current Constant Voltage (CC-CV) charging of Li-ion batteries

The present-day Li-ion batteries when operated, needs precise monitoring of the charging voltage. Several charging techniques have been tested so far with varying degrees of success. One of the most widely used charging techniques is the CC-CV (constant current constant voltage) charging. When performing this, the safety considerations must be maintained with respect to over voltage charging which is a very common problem during constant current charging. In order to prevent over voltage charging, the charging mode must be then shifted from CC to CV mode. So, this transition point of the charging mode from CC to CV is very crucial for the safe operation and health of the battery in the long run. The problem is that, this transition point doesn’t remain the same for the battery. So, in this paper the factors on which it depends are discussed and a Li-ion battery was charged in a few different charging rates using the CC-CV technique to demonstrate the process.