An Automated Combined Microwave and Electric-Element Fish Dryer

This work provides an improvement in the efficiency and economics of the drying process by combining an electric hot air flow and microwave drying unit. It is intended to improve the nutritional qualities for the dried fish market and its shelf life. We fabricated a drying Kiln having combined 1.6KW twin microwave gun and 4KW quad electric element, volume 897,000cm3 and wet fish cargo capacity up to 80Kg. The characteristics of electric drying (ED) and combined microwave-electric drying (MED) of Clarias Gariepinus tissues were studied experimentally. Results show that the moisture ratio decreases with an increase in microwave drying time when microwave power is fixed. The drying rate is fast initially and then falls slowly. Finally, the curve of MED was steeper than that of ED alone during the initial drying period. The data of the percentage of water and volatile oil loss by drying with respect to time follows a logarithmic relationship. The taste panels evaluations and sample results of organoleptic assessment of the dried Clarias Gariepinus was found to range from excellent quality for appearance, taste and odour, good quality for fragmentation and texture. The addition of microwave to the electric heater has saved about 28 hours in drying time and reduced the product cost by energy consumption to 38%. In conclusion this method provides rapid dehydration (shorter drying time), improved product quality and flexibility in drying a wide variety of product

Advances in Perovskite-Based Solar Cells

The increase in energy demand due to increase in population and reduction of fossil fuels has led to the search of alternative energy sources. Solar energy, which is an alternative source of energy, has been in the fore front of this research. Various methods of converting solar energy into electricity has been attained by silicon solar cells, thin film solar cells, dye sensitized solar cells and perovskite solar cells. Unlike dye sensitized solar cells, perovskite solar cells based on lead halide perovskite or organic-inorganic halide perovskite have had a significant impact on photovoltaic devices. A power conversion efficiency of approximately 20.1% has been attained by perovskite solar cells compared to organic solar cells. Also, several fabrication techniques, hole and electron transport materials have been developed for high performance. Although, some issues need to be addressed before commercialization is possible. Issues like stability of the cells under moisture and temperature. In this review, fundamental aspects of the perovskite device and recent breakthroughs are illustrate

The Effect of Electrolyte on Dye Sensitized Solar Cells Using Natural Dye from Mango (M. indica L.) Leaf as Sensitizer

Dye-sensitized solar cells (DSSC) were fabricated with mango leaf dye extracts as natural dye sensitizers at pH value of 5.20 and temperature of 18.1˚C. Methanol was used as dye-extracting solvent. DSSCs from dye extract of M. indica L. with KMnO4 electrolyte had the highest photocurrent density of 1.3 mA/cm2 and fill factor FF of 0.46 for the sun at its peak. Potassium permanganate (KMnO4) had a photocurrent density of 1.3 mA/cm2 and FF of 0.8 at sundown. Potassium Iodide (KI), Potassium Bromide (KBr) and Mercury Chloride (HgCl2) electrolytes had 0.2 mA/cm2, 0.08 mA/cm2 and 0.02 mA/cm2 photocurrent densities respectively. The fill factors of 0.09, 0.03 and 0.003 respectively for sun overhead while 0.08 mA/cm2, 0.01 mA/cm2 and 0.01 mA/cm2 were the values of photocurrent densities respectively at sundown. The fill factors were 0.02, 0.0006 and 0.003 respectively at sundown. The maximum power Pmax of the DSSCs were 0.5 mW/cm2, 0.10 mW/cm2, 0.01 mW/cm2 and 0.012 mW/cm2 respectively at 1300 h at 1630 h 0.9 mW/cm2, 0.14 mW/cm2, 0.005 mW/cm2 and 0.0015 mW/cm2 respectively

Extracts of Cola acuminata, Lupinus arboreus and Bougainvillea spectabilis as Natural Photosensitizers for Dye-Sensitized Solar Cells

Organic dyes from Cola acuminata (C. acuminata), Lupinus arboreus (L. arboreus) and Bougainvillea spectabilis (B. spectabilis) leaves and their mixtures were used as sensitizers to manufacture dye-sensitized solar cells (DSSC). Photoelectric measurements of C. acuminata showed a short circuit current (Jsc) of 0.027 mA/ cm2, 0.026 mA/ cm2 and 0.018 mA/ cm2 with a mixture of mercury chloride and iodine (Hgcl2 + I); potassium bromide and iodine (KBr + I); and potassium chloride and iodine (KCl + I) respectively. The open circuit voltage (Voc) was 24 mV, 25 mV and 20 mV for the three dyes respectively. L. arboreus had Jsc of 0.034 mA/ cm2, 0.021 mA/ cm2 and 0.013 mA/ cm2; and corresponding Voc of 28 mV, 14.2 mV and 15 mV for the three electrolytes respectively. B. spectabilis recorded Jsc 0.023 mA/ cm2, 0.026 mA/ cm2 and 0.015 mA/ cm2; and corresponding Voc values of 6.2 mV, 14.3 mV and 4.0 mV for the three electrolytes respectively. It was observed that the fill factor (FF) was 0.140 for C. acuminata, 0.3198 for L. arboreus and 0.1138 for B. spectabilis. Internal conversions of 0.096%, 0.056% and 0.063% were recorded for three dyes when combined with (KBr + I) electrolyte. The internal efficiency of C. acuminata DSSC was highest in value

Lightning a Fundamental of Atmospheric Electricity

This paper discussed briefly the basic connection between lightning phenomena and atmospheric electricity. Characteristics pertaining to lightning discharges were reviewed in order to elucidate some elementary mystics that are still associated with lightning events in some parts of the world and that lightning strike when and where it will. Various lightning protection principles were discussed. The essence of lightning protection device is to prevent lightning strikes from taking place over or around an installation or structure

Year to year variation of rainfall rate and rainfall regime in Ota, southwest Nigeria for the year 2012 to 2015

The tropics is characterized to have convective type of rainfall which has high occurrence of rainfall compared to the temperate regions of the world. In this paper, the accumulation of rainfall in Ota, Southwest, Nigeria (6o 42 N, 3o 14 E) has been analysed to present the one-minute rainfall rate and the predominant type of rainfall. Four years’ data used for this study was taken using the Davis Wireless vantage Pro2 weather station at Covenant University, Ota, Ogun State. The data collected were used to analyse the one-minute rainfall rate and different types of rainfall predominant in this region. For the prediction and modelling of rain attenuation at microwave frequencies for a region like the Nigeria at various percentage of time, one-minute rainfall rate is required. Nigeria falls into the P zone of 114 mm/hr. as per International Telecommunication Union – Recommendation (ITU-R). The analysis carried out indicated that the measured yearly averaged maximum one-minute rainfall rate for 2012, 2013, 2014 and 2015 are 157.7 mm/h, 148.0 mm/h, 241.2 mm/h and 157.3 mm/h respectively. It also indicated that the drizzle type of rainfall is predominant in contrast to established fact that thunderstorm occurs more in the tropics

Proposed Model for the Estimation of Rain Attenuation: At Ku-Band at Ota, a Tropical Location

This study proposes a model for calculating rain attenuation on earth-space path carried out in Covenant University, Ota, Nigeria, a tropical location. The beacon signals from a geostationary satellite - ASTRA 28°E (2E/2F/2G) was monitored, recorded and analysed using a spectrum analyzer operating at frequencies of 12.245 GHz. Rain rates at the station of the antenna receivers were also logged and analysed. The rainfall rate cumulative distributions and the resultant rain attenuation are obtained and presented. The results obtained showed that the cumulative distribution of the measured rainfall rate is not in agreement with ITU-R prediction. Rainfall rate at 0.001 %, 0.01 %, 0.1 % and 1 % were fed into the existing Simple Attenuation Model (SAM) and corresponding rain attenuation were obtained. The measured rain attenuation from the beacon signal was compared with sixteen existing rain attenuation models in literature only SAM model was closed to the measured result at the location. SAM model overestimated and underestimated the rain attenuation for this location at some percentage of time. Hence, a modified SAM model is proposed using newly obtained specific attenuation coefficients. The proposed modified model is found to be close to the measured rain attenuation

The interboundary properties and kinematics of N719 dye with titania photoanode framework and spectral responses with different electrolytes

Titanium oxide is as ancient in age as our planet but its use for photoanode is more recent. It exists naturally as rutile (the second most abundant), anatase and brookite ores. The anatase several metastable states trigger diverse spectral responses with Magnifera Indica Linn. (M.indica L) dye as it is synthesized with an N719 dye grown on its matrix. Facile doctor blade method and high temperature sintering at 723 Kwere used in fabrication. Doping of titanium oxide in effect lowers the band gap of TiO2 for photo-excitation caused by a bathochromic shift and simultaneously decreases the rate of recombination in photogenerated electron–hole pairs. This study explored the visible light induced photocatalytic action of doped M.indica L DSSC towards reduction of titaniumoxide bandgap. The SEMmicrographs reveal themolecular interactions and the interplay as electrolytes percolate the intricate N719 dye/Titania framework. Detailed analysis stem from comparison of M.indica L crude faction and the batch separated faction using FTIR spectroscopy. The absorbance peak, rates of reaction and % transmittance identify the particular chromophores responsible for the reaction. Result shows the batch-separated hexane faction approximately 1000 times more efficient than its crude faction although the ff of the crude was only about twice that of the hexane faction. The optical study showed that doping ions lead to an increase in the absorption edge wavelength, and a decrease in the band gap energy of TiO2 nanoparticles. The doped TiO2 nanoparticles in general showed higher photocatalytic activities than the pure ones

Estimation of Optimal Insulation Thickness for a Cylindrical Ceramic Crucible

High temperature thermal energy storage (TES) systems have the capacity to achieve high thermal efficiencies due to their high operating temperatures. However, they tend to experience higher thermal losses which adversely affect their thermal cycles. This paper focuses on heat loss estimation from a TES system operating at 800 ℃, insulated in a cylindrical ceramic crucible, and the determination of the optimal insulation thickness of the crucible. Parameters affecting heat loss such as thermal conductivity of the ceramic material and convective heat transfer coefficient were simulated. It was observed that the thermal conductivity of the crucible had a greater effect on the rate of heat loss than the convective heat transfer coefficient. Furthermore, an increase in the length of the crucible increased the thermal mass of the crucible causing it to lose heat at higher rate. The deduced optimal radial thickness for the operating temperature range was 0.075 m. In conclusion, addition of more refractories beyond the optimal radius will not significantly reduce the rate of heat loss and will make the insulating crucible bulkier