Asian Journal of Physical and Chemical Sciences

Experimental Investigation for Augmentation of Thermal Performance of Solar Air Collector

Fri, 23 Jun 2023 00:00:00 +0000

This paper presents a study of the thermal performance of a solar air collector used to heat the drying air of a fruit and vegetable dryer. The prototype collector could be a viable solution to improve energy efficiency and food security in Burkina Faso and other developing countries, by contributing to the reduction of post-harvest losses and the increase of income for local agricultural producers. The collector is first realized by using black painted cans as air ducts, perforated to increase turbulence, and a glass covering the collection surface. After realization, the collector is connected to the dryer and a measurement campaign is conducted to evaluate the thermal performance of it. The measured parameters are the sunshine and the air temperature by keeping the air speed fixed at 0.3 m/s. The analysis of the results shows an important variation of the air temperature difference going from 0.1°C to 74.4°C, between the inlet and the outlet of the collector for an irradiation which varies between 142 W/m² and 837 W/m². The black painted surface of the air ducts as well as the increase in turbulence contributed to improve the efficiency of the collector which varies between 0.94% and 50.68% and allowing to record air temperatures ranging from 27.2°C to 69.2°C inside the dryer. This temperature range is favorable for the drying of most food products.

Influence of the Mirror Reflectance Coefficient on the Performance of the Compound Parabolic Trough Concentrator (CPC): Numerical and Experimental Simulation in a Sahelian Environment

Fri, 23 Jun 2023 00:00:00 +0000

The objective of our study is to numerically and experimentally simulate the CPC operation according to three different values of the mirror reflectance coefficient. The study not only showed the importance of mirror reflectance in the performance of solar collectors but also estimated which of these three values fits well with the reality in the city of Ouagadougou. The thermal exchanges that took place in the CPC were presented. A matlab program was developed for the calculation and simulation of the different parameters of the solar concentrator. The differential equations governing the heat transfers in the different components of the device were discretized by the advanced finite difference method. They were solved by the Gauss-Seidel method. As for the experimental part, it consisted in the direct measurement of the global solar radiation, of the ambient temperature and of the fluid temperature by means of thermocouples placed on the different parts of the sensor. The experimental values are directly recorded with a datalogger. A statistical study was made using some indicators like coefficient of determination of R² , root mean square error (RMSE) and percentage of mean absolute error (MAPE). A validation of the obtained results by comparing the calculated values with the experimental values was presented. The results show that among the three values of the reflectance coefficient, the best results on the temperature of the fluid are obtained with the reflectance coefficient equal to 0.68 on the site of Ouagadougou.

Measurement of Outdoor and Indoor Background Ionizing Radiation of O.B. Lulu Briggs Health Center, University of Port Harcourt, Choba, Rivers State, Nigeria

A. Bubu, C. P. Ononugbo — Tue, 27 Jun 2023 00:00:00 +0000

Measurement of outdoor and indoor background ionizing radiation (BIR) of O.B. Lulu Briggs Health Centre in the University of Port Harcourt, Rivers State, Nigeria was carried out using a well-calibrated Radalert-100 (Radiation meter) and Digilert-200 meters and Global Positioning System (Garmin 765). 30 selected locations were considered. The outdoor and indoor results are as follows respectively, average exposure rates are 0.012±0.001 and 0.013±0.001 mR/h, mean absorbed dose rate (ADR) are 105.6 and 96.28 nGy/h, estimated value of the annual effective dose equivalent (AEDE) are 0.17 and 0.27 mSv/y and mean excess lifetime cancer risk (ELCR) are (0.60 and 0.92) x 10^-3. The obtained values for BIR in O.B. Lulu Briggs Health Centre are not above the recommended standard limit of 0.013mR/h by International Commission on Radiological protection (ICRP). AEDE that was calculated in the entire O.B. Lulu Briggs Health Centre is within safe values, the ELCR and the ADR estimated were higher than the world permissible values of 0.29 x 10^-3 and 84.0 nGy/h respectively. The calculated dose to organs for O.B. Lulu Briggs showed that the testes have the highest organ dose of (0.140667 and 0.218053) mSv/y for outdoor and indoor respectively.

Formulation and Thermomechanical Characterization of Earth-based Biosourced Composites: Cases of Clay-Hibiscus cannabinus L. Fiber, Clay-sawdust and Clay- Oryza sativa Husk

Fri, 14 Jul 2023 00:00:00 +0000

This work concerns the technical study of implementation, thermal and mechanical characterization of a composite material based on clay and plant fibers, in order to meet the need for bioclimatic and sustainable houses. The objective was to find the proportions of clay and fibers to obtain a mixture that would give better thermal properties. A characterization of the thermal properties was made thanks to the KD2 Pro analyzer on samples of various formulas of mixture clay-plant fibers. The results obtained showed that the thermal properties such as thermal conductivity and thermal diffusivity of the clay-fiber mixture samples decrease with the increase of the fiber content in the mixture. Thus, the thermal conductivity of the samples varies from 0.85 to 0.65 W/m.K; from 0.88 to 0.72 W/m.K and from 0.83 to 0.75 W/m.K respectively with Hibiscus cannabinus L. fiber, sawdust and Oryza sativa husk. As for the thermal diffusivity, it varies from 0.37 to 0.25 mm²/s; from 0.45 to 0.30 mm²/s and from 0.47 to 0.27 mm²/s respectively with the addition of Hibiscus cannabinus L. fibers, sawdust and Oryza sativa husk. In sum, the earth samples stabilized with Hibiscus cannabinus L. fibers offer better thermal properties for the construction of bioclimatic houses.

Synthesis of Cu2-x Ni0.05 S (x=0.05,0.25,0.30) Compounds and Study of Single Crystals

Kh. Kh. Hashimov — Tue, 01 Aug 2023 00:00:00 +0000

In the article, considering the research studies of many scientists and also on the basis of practical applications, the distribution diagram of copper and sulfur atoms in the phase lattice of the crystal, the structure transformation diagram, the elemental lattice hexagonal and crystallographic data were examined and important results were obtained. Analysis of the studies performed shows that some conflicting results in roentgenographic studies on these compounds are related to obtaining these samples by different methods.

Our goal is to obtain single crystals of the compounds Cu_2-xNi_0.05S (x=0.05,0.25,0.30) and draw the lauegrams and debayograms of those crystals. Then the results were analyzed.

During the research, it was found that it is possible to buy single crystals of compounds based on the analysis of existing methods and selection of the optimal method. As a result of the research, the suitable lauegrams of the single crystals obtained by the Bridgman method and the microstructures of the samples were determined and the possibilities of application were determined.

Effect of Additives on Decomposition of Methyl Orange and Congo Red Dyes Found in Industrial Wastewater

Tue, 01 Aug 2023 00:00:00 +0000

A number of textile industries are using different types of dyes which can be a threat to the environment when they are directly exposed without any treatment. The advanced oxidation process (AOP) has become one of the popular methods in which the dye molecules are degraded using microwave irradiation. This method has become popular due to its eco-friendly and cost-efficient characteristics. In this article, the author has reported the degradation of two azo dyes, named methyl orange (MO) and congo red (CR), in the presence of inorganic salts, some additives like charcoal, H₂O₂, CCl₄, tert-butyl alcohol (TBA), glucose and sucrose. A comparative study was conducted to find out the relative degradation rate enhanced by various additives. For both of the dyes, it was found that charcoal was the most effective additive and significantly enhanced the degradation rate mainly due to its high adsorption capability. TBA was found to be the least enhancer. The order of effectiveness based on the irradiation period for MO was 0.01g charcoal > 20 ml NaCl > 20 ml Na₂SO₄> 20ml glucose> 10 ml sucrose > 100 μL CCl₄> 200 μL H₂O₂> pure MO > TBA. On the other hand, the order of effectiveness for CR for the same condition of irradiation was Combined additives>0.01g charcoal > TBA > 100 μL CCl₄> pure CR.

Search for Qualified Soil for the Production of Low-Energy Biobased Composite Materials

Thu, 24 Aug 2023 00:00:00 +0000

The development of earth-based bio-sourced materials requires a thorough analysis of the study soil. For the present study, we took five (05) soil samples from a tunnel-digged quarry in the layer between 0.5 m and 5 m : white clay (MSB-BL), red clay (MSB-RG), weak clay or sandy clay (MSB-FB), strong clay (MSB-FR) and mixture (MSB-ME). To verify the quality of these five (05) soils samples, their intrinsic properties were determined at the National Building and Public Works Laboratory (LNBTP). These included grain size, clay content, specific weight, loss on ignition and moisture content. These analyses revealed that MSG-RG and MSG-BL clays have fine fractions of 64.28% and 47.85% respectively; clay fractions of 27.51% and 20.61% respectively; and methylene blue values in the range (6;8). Their plasticity indices are in the range (20;40). These two (02) clays thus meet the requirements in terms of granularity, and their relatively high clay fraction will favor their adhesion with admixtures such as plant fibers. What's more, the particle size distribution of these clays is within the ideal CRAterre range for soils used in the manufacture of BTC or adobes, so they are all eligible.

A Geo-Electric Survey of Potential Aquifer Inome Parts of Amaigbo, in Imo State, Using Vertical Electrical Sounding and Well Log Data

Deborah Chidimma Ndubueze , Jiriwari Amoneah , Opiriyabo Horsfal — Sat, 09 Sep 2023 00:00:00 +0000

The method employed was an electrical resistivity survey which was carried out to study the subsurface layer with a view of determine the depth of potential aquifers, the thickness of an aquifer, and to determine the potential aquifer for groundwater exploration. Using the Schlumberger array technique, Vertical Electric Sounding (VES), along with Self Potential well logging was carried out at six (6) VES stations in Amaigbo using the ABEM SAS 1000 terrameter and ABEM SAS 1000 logger respectively. The field data obtained have been analysed using the computer software (IP2win) which automatically interprets the apparent resistivity. The VES result revealed the heterogeneous nature of the subsurface geological sequence. Result from the Geo-electric section showed that the aquifer resistivity of the study ranges from 352\(\Omega\)\(\mathit{m}\) to 7514\(\Omega\)\(\mathit{m}\) , with potential groundwater depths ranging from 45m to 119m which shows that the study area is perfect for groundwater development. The data from the SP well logs correspond to the VES data obtained.