A novel multilevel DC - AC converter from green energy power generators using step-square waving and PWM technique

Green energy sources or renewable energy system generally utilize modular approach in their design. This sort of power sources are generally in DC form or in single cases AC. Due to high fluctuation in the natural origin of this energy (wind & solar) source they are stored as DC. DC power however are difficult to transfer over long distances hence DC to AC converters and storage system are very important in green energy system design. In this work we have designed a novel multilevel DC to AC converter that takes into account the modular design of green energy systems. A power conversion efficiency of 99% with reduced total harmonic distortion (THD) was recorded from our simulated system design

Development of an improved dug canoe for artisanal fisheries

A dug canoe similar to the one commonly used by artisanal fisherfolks 4.82M (LOA) was designed and constructed using locally available materials, as an alternative to hardwood that is becoming very scarce. The canoe have least cost, easy construction, adequate stability, light weight and easy maneuverability, as its attributes. The light displacement (weight empty) was 37kg which is light enough in relation to craft of same size commonly used by fishermen. The capacity of the canoe was 210 kg (3 persons) and total production cost of N18,400 which is not beyond the reach of an average fisherfolk. The craft is small and fall among the category of crafts that account for the greater percentage of national fish landing. The canoe also closely resembles the local fishing crafts, hence easy acceptance by local fisherfolk

Real time telemedical health care systems with wearable sensors

The time between detection and response to chronic diseases could go a long way in saving lives. The current trend in health monitoring systems is to move from the hospital centered device to eventually portable personal devices. Hence,Telemedical health care involves the remote delivery of medical care service to either out-of-hospital or admitted patients through wireless network and computer information technology. This paper systematically reviews the most recent works in telemedical health care system to propose a more efficient model. The focus is more on wearable sensors and devices with most attention given to cardiovascular patients in recent times. The huge literature available reflects the size of activity and attention given to telemedicine. The reviewed works are published within the last five years. Furthermore, the proposed systems are compared in terms of their connectivity, targeted application, type of sensor used, etc. Our study reveals Telemedicine to be a profound field with researchers from multidisciplinary sectors. However, there are still many gaps that need to be filled before maturity. Factors such as efficient wireless transmission, cyber data security, sensor design and integration, device miniaturization and intelligent algorithm for multi parameter data fusion require further considerations

Induced current distribution in 3D soil model as lightning impulse discharge strike earth surface

Discharge current distribution generated as a lightning strike traverse from the atmosphere into a soil surface and below with varying conductivity were investigated using a laboratory-size electrode configuration system consisting of a point discharge electrode and nine under-soil grounding electrodes. Discharge emission and the electric potential of the soil were with significant change upon slight variation in soil conductivity across the surface and along with an increase in depth. Non-linear degradation phenomena in the soil conductivity also occur after a subsequent discharge of lightning strike indicating a breakdown of soil properties. The results of a numerical model in COMSOL Multiphysics AC/DC module further shed a graphical illustration of the current pathway validating the experimental data. © 2019 IEEE

Government Spending and Inclusive-Growth Relationship in Nigeria: An Empirical Investigation

This study has investigated the relationship between government spending and inclusive growth in Nigeria over the period 1995 to 2014. Specifically, it examined how, and to what extent, government spending on education, government spending on health, economic freedom, public resource use, and real GDP growth rate have impacted on inclusive growth in the country. It used the Dickey-Fuller GLS unit root test to ascertain the order of integration of the series. Consequently, through the Auto-Regressive Distributed Lag (ARDL) bound testing technique, the study found that in the long-run government spending on health, economic freedom, public resource use and real GDP growth rate had significantly positive influence on inclusive growth. In the short-run, however, only real GDP impacted significantly on inclusive growth while other variables were not significant in causing inclusive growth. Thus, in conclusion, government spending in the form of redistributive spending on health propelled inclusive growth in Nigeria

Production of Proteolytic Enzyme from Catfish Waste Using Bacillus subtilis, Proteus vulgaris, and Arthrobacter aurescens

The world marine captured fishes contribute to more than 50 % of the total world fish production. About 70 % of fish is processed before final sale, resulting in 20-80 %  of  fish  waste  depending  on  the  level  of  processing  and  type  of  fish. The majority of fish wastes are disposed of in the ocean as well as on land. The discards from  the  processing  plants  amount  to  20  million  tonnes,  which  is  equivalent  to  25 %  of  the  world's  total  production  from marine captured fisheries. The fish processing industry generates considerable amounts of by-products such as waste that includes shells, scales, fins and bone frames. Interestingly, they are all often high in protein, which can be processed into useful products. Three organisms Bacillus subtilis, Proteus vulgaris, and Arthrobacter aurescens were isolated and used in the production of the proteolytic enzyme in three different protease production media. B. subtilis, P. vulgaris and A. aurescens were observed to have produced protease best at 48 hr of the second production, 72 hr of the third production, and 72 hr of first production, respectively. Fish waste should not be discarded into the environment, which can cause adverse effect on human health and environmental pollution, but rather they can be used in industries such as food industry in the production of baby foods to help break down the available protein into amino acids required by the body. Keywords: Environmental pollution, Marine habitat, Fish processing, Food protein, Food industr

Analytical investigation of step-square wave in time and frequency domain using transform equations

A unit step function can be used for generating a pulse of given width and height. The same pulse can be used for generating a stepped waveform of known levels and a given width in time-domain which when translated to frequency or complex S-domain provides the fundamental constituent frequencies. This paper is about studying the frequency of the above-generated functions in time as well in the frequency domain using transform equations. The result of this simulations are indicative of the correlation between step square waving and reductions in total harmonic distortion (THD) during DC to AC conversion. A decrease in the pulse width difference between each step shows better conversion with reduced harmonics when subjected to simple passive filter of low transfer function

Watermarking in protecting and validating the integrity of digital information: a case study of the holy scripture

This paper presents digital watermarking for validating and protecting the integrity of digital Holy Quran in Portable Document Format (PDF). The need arises as minute alteration to text or content of Holy Scriptures could result in a devastating situation in the belief of the owners. By this research we have designed and evaluated a simple yet fragile and fidel image PDF digital watermarking technique using 2 and 4 level Discrete Wavelet Transform (DWT) in order to protect and detect the authenticity of a digital Holy Quran. A 512×512 PDF Quran was used as cover image and DWT carried out on it following the watermark image embedding process of a 128×128 and 32×32 on different trials. The Inverse DWT then carried out to obtain the watermarked Quran PDF. Imperceptibility test using Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index (SSIM) were used to evaluate the fidelity and fragility of the watermark scheme over four different embedding gain (k) of 0.001, 0.002, 0.003 and 0.004 for a more robust system. The experimental results demonstrated that our system was indeed effective

Climate-resilient development: An approach to sustainable food production in sub-Saharan Africa

Climate change is profoundly affecting many activities in the agricultural sector in almost all regions of the world. To adapt to the prevailing climatic conditions has translated into a cascade of risks for agro-ecosystems and agricultural production, ultimately impacting food security and nutrition. Hence, the study examines the effect of climate change on food production in 32 sub-Saharan African (SSA) countries between 2005 and 2019 using Fixed Effects (FE) and Two-Step System-Generalized Method of Moments (GMM) estimation. Findings help better understand the link resulting from climate change to adverse impacts on food production, as empirical analyses indicate that an increase in climate change (CO2 emissions) will result in a significant reduction in food production in SSA. This implies that climate change seems to have significantly contributed to the challenges associated with food insecurity in the region. Via changes in average temperature and rainfall patterns, climate change could be exacerbating existing threats and issues related to food production in the SSA region. It is therefore suggested that to mitigate the negative impacts of climate change on food production, policy makers should aim at encouraging and adopting good adaptation approach, primarily at the production stage of food supply

Design of simple DC-to-DC wireless power transfer via inductive coupling

This research presents a wireless DC-to-DC power transfer over a short distance. Distance of remotely located target from the source coil and received voltage at the load are the major concern in the Wireless Power Transfer (WPT) applications. The inversely proportional behavior of these parameters degrades the system performance. In order to optimize these values and achieving transfer efficiency, microelectronic circuit is developed and simulated using NI Multisim. The transmitter and receiver modules are constructed and their individual blocks are simulated and analyzed for wireless power transfer. Two inductively coupled coils are designed and used in both transmitter and receiver sections. The inverter is designed using H-bridge with five CMOSFET (IRF520NS, IRF5210S) and its gate signal is generated using NE555 timer IC with two output clock signal where one was inverted using an NMOS inverter. Through simulation, it is observed that with such a design, the power transfer has a limited range, and the range will be smaller for smaller receiving coils and improper alignment. A simulated model is proposed and implemented in this paper. The simulation outputs of each unit is plotted and analyzed separately. In addition, transient plot of load resistance versus output voltage are illustrated to analyze the power of dc-dc power transfer circuit. It is observed that the output voltage is increased correspondingly with increasing load resistance and determined good output voltage is harvested with the optimized load resistance is at 1 kΩ and is 4.25 V. Simulated results shows that the proposed system can transfer power with high efficiency. This proposed system could be made commercially viable through further research work