Open Access Original Research Article

Effect of Dust Deposition on the Quantum Efficiency of BPS150-36 Polycrystalline Silicon Photovoltaic Modules during Winter Months in Pahou, Benin

Minadohona Maxime Capo-Chichi, Basile Bruno Kounouhéwa, Vianou Irénée Madogni, Macaire Agbomahéna

Advances in Research, Page 1-16
DOI: 10.9734/AIR/2018/43283

Dust is the lesser acknowledged factor that significantly influences the performance of the PV cells/modules.

We investigated analytically from optical models, the performance degradation of the BPS150-36 Polycrystalline silicon module, caused by the natural dust deposition effects on the transparent panel surface. 

We modeled, a system (Air-dust-glass) formed of a dust layer supposed opaque and formed of several thousand small grains of different sizes settled on the glass surface. The Matrix-Transfer theory with the cubic spline interpolation method has been exploited for data correlation. Matlab software has been used to results in numerical simulation.

The results obtained show a decrease in PV output intensity, the supply voltage and therefore the power output. That strongly depends on dust thickness on the panel’s surface over a period of three months.

The drop in PV cell quantum efficiency is directly caused by the dust accumulation, trees debris and bird’s droppings on the cells/modules surface. The meteorological conditions, the installations quality and the geographical position of PV cells/modules can also influence the photovoltaic process. These factors have not been taken into account in our model.

Open Access Original Research Article

Potential Probiotic Properties of Lactic Acid Bacteria Isolated from Malted and Spontaneously Fermented Acha (Digitaria exilis) Flour

S. M. Wakil, E. M. Olorode

Advances in Research, Page 1-12
DOI: 10.9734/AIR/2018/45414

Aim: To isolate, characterise and identify Lactic Acid Bacteria (LAB) with potential probiotic properties from malted and fermented Acha (Digitaria exilis).

Place and Duration of Study: The study was carried out at the Department of Microbiology, University of Ibadan, between May 2017 and October, 2017.

Methodology: Collected acha grains was sorted, malted for 48 hours, dried milled and sieved. The flour was reconstituted, fermented spontaneously for 72 hours and sampled every 24 hours for isolation of LAB.

Results: The probiotic properties of 40 LAB strains isolated were evaluated in vitro. Based on their antimicrobial activity against some common foodborne pathogen and antibiotic susceptibility pattern to standard antibiotics, 14 LAB strains were selected for further screening. They all exhibited strong antimicrobial activity against Staphylococcus aureus, Salmonella sp., Escherichia coli, Bacillus sp. and Pseudomonas aeruginosa. All selected strains were investigated for acidic pH and bile salt tolerance, tolerance to NaCl and simulated gastric juice, cell surface characteristics which includes hydrophobicity and auto-aggregation assay. Production of DNAase, gelatinase, Exopolysaccharide and haemolytic ability were investigated for safety assessment. Five strains (L12, L15, L118, L213, L214) exhibited tolerance to 10% NaCl concentration and pH 2. All the selected 14 LAB strains resisted the bile salt up to 1.0% except L15 and tolerated simulated gastric juice with a sharp decrease by 90min followed by an increase in the count after 180 min except for isolates L12 and L17. Auto-aggregation value ranged from 0.88% to 93.71% with the highest value recorded for L17 (93.71%). LAB117 had the highest (43.39%) microbial adherence to hydrocarbon (MATH) value and least in L19 (2.08%). All the 14 LAB strains were negative to safety tests but all produced exopolysaccharide except LAB L13 and L19. Based on the morphological, biochemical and physiological characteristics, the 14 LAB isolates were identified as Lactobacillus plantarum (L15, L17, L117, L214), Lactobacillus casei (L113, L116, L213), Lactobacillus sp. (L13, L19, L22, L211), Enterococcus sp. (L12, L115) and Pediococcus sp. (L118).

Conclusion: The selected 14 isolates have the probiotic properties required for use as a potential probiotic in weaning food supplements with the best probiotic properties recorded with Lactobacillus plantarum L117 strain.

Open Access Original Research Article

Experimental and Numerical Study on Strengthening of R.C Slabs at Tension Side Using Lower Concrete Layer Reinforced by FRP Elements

K. M. El-Sayed, E. A. El-kasaby, M. A. El-maasrawy

Advances in Research, Page 1-22
DOI: 10.9734/AIR/2018/45688

Aims: Study the strengthening of reinforced concrete slabs at tension side using lower concrete layer reinforced by FRP bars. The proposed layer improves strongly the flexural strength and the rigidity of R.C slabs, moreover, FRP elements are noncorrosive in contrast with the traditional strengthening layers reinforced by steel bars.

Study Design: Parametric study is carried out by varying the material type, thickness of strengthening layer, spacing between strengthening layer reinforcement bars, cross sectional area of this reinforcement and the type of the strengthening reinforcement.

Methodology: This study presents the efficiency of adding lower concrete layer reinforced by different materials to increase the flexural strength for two-way R.C slabs. Eleven half-scale two-way R.C slab specimens were prepared and tested under four point bending. One of these slabs was unstrengthened and considered as a control specimen. The other specimens were strengthened by using different lower concrete layers reinforced mainly by fiber reinforced polymer (FRP) bars. The parameters of this study included the material type (reinforcement steel, glass fiber and carbon fiber), the thickness of strengthening layer (30 & 50 mm), spacing between strengthening layer reinforcement bars (100 & 200 mm), cross sectional area of this reinforcement (A & 2A) and the type of the strengthening reinforcement (FRP bars & FRP strips).

Results: The experimental results included cracking load, ultimate load, load-deflection relationships, relative ductility, and flexural stiffness.

Conclusion: The experimental results showed an improvement in the flexural behavior of the strengthened specimens compared to control specimen. The flexural strength of the different strengthened specimens increased by 37% to 112% compared to the control specimen. Moreover, a finite element models were developed by ANSYS (version 15) to simulate all the tested specimens. The results calculated based on FEM models were in good agreement with the corresponding experimental ones. However, the calculated ultimate loads were slightly higher than the experimental ultimate loads up to 12%.

Open Access Original Research Article

Diversity of Ant Species (Hymenoptera: Formicidae) Nesting Beneath Different Trees in Periyanaickenpalyam, Coimbatore District, Tamil Nadu

J. Sornapriya, K. Varunprasath

Advances in Research, Page 1-8
DOI: 10.9734/AIR/2018/43338

Ants (Formicidae: Hymenoptera) are one of the most successful organisms of the tropics and have survived many geological changes in the past and play crucial roles in ecosystem functioning. The present study examined ants nesting beneath different trees in Periyanaickenpalyam village, from November 2017 to February 2018. The study observed that 384 ants nests associated with 27 floral species at different locations in Periyanaickenpalyam were recorded. Based on floral ants nest association maximum of 18% ants nest in the Prosopis juliflora species followed by 15% of Azadirachta indica, Ficus religiosa contain 12%, Mangifera indica cover 9%, Shorea robusta (6%) and Toona ciliata equally contain (6%) and rest of floral species Cocos nucifera, Ficus benghalensis, Santalum album, Gmelina arborea, Bambuseae, carica papaya, Thespepsia populnea, Delonix, Tamarinds indica, Cassia fistula, Musa acuminate each contain (3%) were observed. According to nest wise, fifty four nest below the Prosopis juliflora followed by fifty two nests in Azadirachta indica, (49) nests  engaged in ficus religiosa, forty nests in Mangifera indica and twenty three nests beneath the Shorea robusta, Ficus benghalensis each and in Toona ciliata, Bambuseae both contain twenty two nests, reset of species contain less than 15 ants in Gmelina arborea, Carica papaya, Delonix, Cocos nucifera, Santalum album, Musa acuminate, Tamarinds indica, Cassia fistula and Thespepsia populnea trees were observed from the study. It can be concluded that this study provides clue information on ants nesting association with floral species.

Open Access Original Research Article

Development of a Laboratory Metallographic Grinding/Polishing Machine

Oyetunji Akinlabi, Barnabas Abel, Obolo Olupitan Emmanuel

Advances in Research, Page 1-13
DOI: 10.9734/AIR/2018/38890

This study centered on the development of a laboratory metallographic grinding/polishing machine using locally sourced materials and indigenous technology to help in polishing metals for production of a flat, smooth and mirror-like surface of any metallic materials to determine their physical structure using microscopy for metallographic examinations. The designed was made, and 3-dimensional architectural design was done to obtain a clear vision of the design. The laboratory grinding/polishing machine was fabricated using the following components: Angle-bars, mild steel plate, electric motor, shaft, belt, pulley, coupling, side pulley disc; following the specified dimensions from the 3-dimensional drawing; assembling of the various components follows; and finally, tested and performance evaluation was equally done. In testing the developed machine, the specimen was mounted, ground and then polished using emery paper with frequent application of water to act as a coolant while the side pulley disc is rotating. The result obtained from the developed laboratory grinding/polishing machine showed a metallic specimen that was well ground and well-polished to mirror-like form for further metallographic examination. Based on the efficiency of this developed machine, we, therefore, recommend this research work for the end users and the metallography industry for the metallographic purpose.