Open Access Original Research Article

The Effect of Irradiance and Temperature on the Performance of Monocrystalline Silicon Solar Module in Kakamega

Ligavo Margdaline Musanga, Wafula Henry Barasa, Mageto Maxwell

Physical Science International Journal, Page 1-9
DOI: 10.9734/PSIJ/2018/44862

Solar energy can be harnessed as photovoltaic energy or solar thermal. Photovoltaic modules provide safe, reliable, and maintenance-free, without noise and environmentally friendly source of power This paper evaluates the outdoor performance of a monocrystalline silicon module based on irradiance and temperature in Kakamega region. The outdoor performance characterisation of a 20 W mono-crystalline silicon module was investigated under different values of solar irradiance and module surface temperature in Kakamega, Kenya. Short circuit current of the module increased significantly with increasing irradiance while open circuit voltage was least affected. Both fill factor and efficiency showed a similar trend with irradiance, increasing slightly and then reducing. The response variables; fill factor, efficiency, open circuit voltage and maximum power were found to reduce with increase in surface temperature while short circuit current increased slightly. The average efficiency, fill factor, short circuit current and open circuit voltage for the module was found to be 10.11%, 0.65, 0.65A, and 19.78V respectively. Maximum Voltage, maximum current and maximum power were found to be 16.78V, 0.48A and 8.11W respectively. A good knowledge of the power output of a solar module and how it varies with solar irradiance and temperature would give accurate information which is vital in sizing and design of photovoltaic system.

Open Access Original Research Article

The Influence of Mechanical-stress on the Quartz Filter Features

Gao Ao, Xia Gang, Kong Yong

Physical Science International Journal, Page 1-6
DOI: 10.9734/PSIJ/2018/19858

In order to study the effect of mechanical-stress on the quartz filter output, based on the elasto-optical effect of quartz crystal, the relationship between berifringent difference of quratz plate and mechanical-stress is deduced, the experimental system is set up by using Ultra-6600 UV spectrophotometer, and received the transmission spectrum of Lyot quartz birefringence filter, the transmission spectrum was investigated theoretically and experimentally in detail. The results show that when applied different mechanical stresses, the center wavelength of quartz birefringent filter changed, and the drifting direction of the center wavelength is related to the size of applied mechanical stress, the drifting size of the center wavelength is related to the direction of applied mechanical stress. It is helpful for the manufacturing, correct design and application of quartz birefringence filter.

Open Access Original Research Article

2D-simulation of Nanopowder High-Speed Compaction

G. Sh. Boltachev, N. B. Volkov, A. V. Spirin, E. A. Chingina

Physical Science International Journal, Page 1-8
DOI: 10.9734/PSIJ/2018/45057

The paper concerns the nanopowder high-speed, 104 – 109 s–1, compaction processes modelling by a two-dimensional granular dynamics method. Nanoparticles interaction, in addition to known contact laws, included dispersive attraction, the formation of a strong interparticle bonding (powder agglomeration) as well as the forces caused by viscous stresses in the contact region. For different densification rates, the "pressure vs. density" curves (densification curves) were calculated. Relaxation of the stresses after the compression stage was analysed as well. The densification curves analysis allowed us to suggest the dependence of compaction pressure as a function of strain rate. It was found that in contrast to the plastic flow of metals, where the yield strength is proportional to the logarithm of the strain rate, the power-law dependence of applied pressure on the strain rate as was established for the modelled nanosized powders.

Open Access Original Research Article

Wave Energy Resources Assessment Offshore Benin from ERA Re-Analysis: Gulf of Guinea

Guy Hervé Hounguè, Basile Bruno Kounouhéwa, Mathias Adjimon Houékpohéha, Bernard Noukpo Tokpohozin, Vianou Irénée Madogni

Physical Science International Journal, Page 1-11
DOI: 10.9734/PSIJ/2018/44226

Wave energy recovery in coastal zones can provide mitigation of flooding and play a very important role in the protection of the coastline.

Wave energy potential off the coast of Benin has been investigated from ECMWF ERA reanalysis (ERA40 + ERA-Interim). ERA data have been adjusted with in situ data coming from the buoy installed off Autonomous Port of Cotonou (Benin) over a period of 60 years. Next, wave energy resources have been evaluated using the Wang and Lu [1] model for medium water depths.

The simulated results showed that in Benin's coastal area, wave energy is moderate and available. At a seasonal scale, wave energy increases from January to August, decreases until December with values ranging from 9.84 to 22.35 kW/m and an average of 15.64 kW/m. The maximum value has been observed in summer and autumn. At the inter-annual scale, an increasing trend of wave energy has been observed with a fluctuation of about of 2.47 kW/m. Wave energy resource available in Benin's coastal area has been evaluated to 144.99 kWh/m per wavefront.

Wave energy resources would be an efficient supplemental source, and its exploitation would contribute to energy self-sufficiency and play an important role in the coastal protection of the country.

Open Access Original Research Article

Probability Distribution of Daily Rainfall Pattern over Some Selected Stations in North Western Nigeria

I. Garba, A. Akinbobola, E. C. Okogbue

Physical Science International Journal, Page 1-13
DOI: 10.9734/PSIJ/2018/44983

Analysis of rainfall distribution is important in studying the impact of changing weather and climate on water resources planning and management. This study assessed the performance of three different probability distribution models, namely: Generalized Extreme Value Distribution (GEV), Lognormal Distribution (LNG) and Gumbel (EV1) Distribution to describe the rainfall distribution patterns in some selected stations (Gusau, Yelwa and Sokoto) in North-Western Nigeria. Thirty years of daily rainfall data for the period of (1985-2014) for the selected stations were obtained from the archives of the Nigerian Meteorological Agency (NIMET), Abuja. The aim of the study is to determine the distribution model that best describes the distribution of daily precipitation in North-Western Nigeria and also to identify the effect of plotting position on existing models. Root mean square error (RMSE) was used to determine the efficiency of the different plotting formulae on the existing model. The model performance was evaluated based on the statistical goodness of fit test, namely Kolmogorov-Smirnov (KS) at 95% (α=0.05) significant level. The method of moment (MOM), Probability weight-moment and maximum of likelihood were used for estimating the models parameters. The result shows that the probability distribution model that best fit the data based on statistical of goodness of fit test is the EV1 followed by LNG then GEV. The EV1 model gave the smallest value of KS test for all stations except Gusau station where LNG model was the most suitable. The best plotting position formula with the entire distribution model was also observed to be the Weibull plotting position formula followed by Chegodayev, Gringoten and Hazen plotting position respectively. Hazen plotting position gave minimal errors with the EV1 and GEV probability distributions, while Weibull gave a minimal error with the LNG probability distribution for all the stations. The EV1 model was found to be the most suitable distribution for modelling the daily rainfall distribution in two out of the three stations investigated, while the LNG was observed to be only suitable for Gusau. The result of this work has provided information on rainfall probabilities as a vital tool for the design of water supply and supplemental irrigation schemes and the evaluation of alternative cropping and of soil water management plans.