Development and performance evaluation of a natural draft mixed-type solar dryer for agricultural products

Reduced moisture content enhances storage properties of agricultural products and reduces post-harvest losses. Effective drying can be achieved using solar dryers in regions with abundant solar radiation. In this study, a natural draft mixed-type solar dryer suitable for rural communities of developing countries was developed. The performance of the solar dryer was also investigated using pepper, okra and tomato. The temperature taken at different points of the drying chamber and the auxiliary collector show that the temperature within the drying chamber is higher than the ambient temperature. The temperature within the drying chamber was also found to depend on the atmospheric conditions. The maximum drying rate was obtained at periods between 1200 and 1400 hrs Nigeria local time during which the temperature within the solar dryer is also maximum. Temperature within the solar dryer reached up to 62°C. The solar collector efficiency was 52.0% while the drying efficiency was 21.9%.Peer reviewe

Periodicity, Stability, and Boundedness of Solutions to Certain Second Order Delay Differential Equations

The behaviour of solutions to certain second order nonlinear delay differential equations with variable deviating arguments is discussed. The main procedure lies in the properties of a complete Lyapunov functional which is used to obtain suitable criteria to guarantee existence of unique solutions that are periodic, uniformly asymptotically stable, and uniformly ultimately bounded. Obtained results are new and also complement related ones that have appeared in the literature. Moreover, examples are given to illustrate the feasibility and correctness of the main results

HEPATOPROTECTIVE EFFECT OF METHANOLIC LEAVE EXTRACTS OF V. ALBUM ON PARACETAMOL-INDUCED LABORATORY ANIMALS

Abstract. Hepatoprotective assay was carried out on laboratory animals in which paracetamol (oral dose,2 g/kg /body weight) was used to induce hepatotoxicity. The animals were orogastrically fed with the Viscum album (growing on cocoa and cola host trees) methanolic leave extracts. The activities of serum enzyme biomarkers showed no significant difference (P< 0.05) for V. album growing on cocoa (1000-5000mg/kg) but there were corresponding significant increase in the serum enzymes (P< 0.05) for V. album growing on cola at 4000 and 5000 mg/kg doses. Similarly, the photomicrograms of the animals' vital organs (liver, stomach, small intestine and kidneys) studied revealed that V. album extract growing on cocoa was more hepatoprotective efficacious than that growing on cola tree on all the biochemical parameters that were screened for when compared with sylimarin (a standard heptoprotective drug)

Comparative antibacterial studies of mistletoes growing on two diffrent host plants in Akure North, Nigeria

The antibacterial activity of 60 % methanolic leaves extracts of mistletoes (Viscum album) growing on cocoa and cola trees were tested on Bacillus cereus, Pseudomonas aeruginosa,Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi in vitro. Both the gram-positive and gramnegative organisms showed variable sensitivity to the extracts treatments. The results obtained indicated that extracts from both host plants had some antibacteria activities against the microorganisms when compared with standard antimicrobial agents (ciprofloxacin and sterptomycin) used as positive controls at P < 0.05 significant level. In general,extracts from cocoa (Theobroma cacao) plant showed more antimicrobial tendency than those from cola (Kola nitida) plant

GC-MS Analysis, Antimicrobial and Antioxidant Activities of Extracts of the Aerial Parts of Conyza sumatrensis

Phytochemical analyses as well as antimicrobial and antioxidant activities of the extracts of C. sumatrensis aerial parts were investigated in this study. METHODS: The aerial parts of C. sumatrensis were air dried, weighed and exhaustively extracted with hexane, ethyl acetate and methanol successively. The crude extracts were screened for metabolites.  These extracts of the plant were evaluated for antimicrobial and antioxidant activities using agar  diffusion and DPPH method respectively. The extracts were also analysed using Gas chromatography – Mass spectrometry, and the chromatogram coupled with mass spectra of the compounds were matched with a standard library. RESULTS: Preliminary phytochemical investigation of  rude n-hexane, ethyl acetate and methanol extracts of the aerial parts of Conyza sumatrensis revealed the presence of anthraquinones, flavonoids, terpenoids, phenolics, tannin, glycosides and carbohydrate. All the crude  extracts gave a clear zone of inhibition against the growth of the test bacteria (Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomona aeruginosa, Salmonella typhi, Klebsiellae pneumonae) at moderate to high  concentrations, as well as test fungi (Candida albicans, Aspergillus niger, penicillium notatum and  Rhizopus stolonifer) at high concentration. Methanolic extract exhibited significant radical scavenging  property with IC50 of 17.08 μg/mL while n-hexane and ethyl acetate extracts showed no significant antioxidant activity. GC-MS of N-hexane extract showed a total number of eleven chemical constituents with α-Farnesene and spathulenol being the most abundance compounds constituting 20.27 and 22.28% of the extract respectively. Ethyl acetate extract revealed thirteen  compounds with two most abundant compounds, cis-β-farnesene (16.64 %) and cis-pinane (21.09 %). While  methanolic extract affords seventeen compounds with Ephytol being the most abundant compound  (19.36 %). © JASEMKeywords: Antimicrobial activity, Antioxidant, GC-MS analysis, Phytochemicals, Conyza sumatrensi

Reactogenicity, safety and immunogenicity of a protein-based pneumococcal vaccine in Gambian children aged 2-4 years: A phase II randomized study.

Pneumococcal conjugate vaccines (PCVs) have been successful in preventing invasive pneumococcal disease but effectiveness has been challenged by replacement of vaccine serotypes with non-vaccine serotypes. Vaccines targeting common pneumococcal protein(s) found in most/all pneumococci may overcome this limitation. This phase II study assessed safety and immunogenicity of a new protein-based pneumococcal vaccine containing polysaccharide conjugates of 10 pneumococcal serotypes combined with pneumolysin toxoid(dPly) and pneumococcal histidine triad protein D(PhtD) (PHiD-CV/dPly/PhtD-30) in African children. 120 Gambian children (2-4 years, not previously vaccinated against Streptococcus pneumoniae) randomized (1:1) received a single dose of PHiD-CV/dPly/PhtD-30 or PCV13. Adverse events occurring over 4 d post-vaccination were reported, and blood samples obtained pre- and 1-month post-vaccination. Serious adverse events were reported for 6 months post-vaccination. Solicited local and systemic adverse events were reported at similar frequency in each group. One child (PHiD-CV/dPly/PhtD-30 group) reported a grade 3 local reaction to vaccination. Haematological and biochemical parameters seemed similar pre- and 1-month post-vaccination in each group. High pre-vaccination Ply and PhtD antibody concentrations were observed in each group, but only increased in PHiD-CV/dPly/PhtD-30 vaccinees one month post-vaccination. One month post-vaccination, for each vaccine serotype ≥96.2% of PHiD-CV/dPly/PhtD-30 vaccinees had serotype-specific polysaccharide antibody concentrations ≥0.20µg/mL except serotypes 6B (80.8%) and 23F (65.4%), and ≥94.1% had OPA titres of ≥8 except serotypes 1 (51.9%), 5 (38.5%) and 6B (78.0%), within ranges seen in PCV13-vaccinated children. A single dose of PHiD-CV/dPly/PhtD-30 vaccine, administered to Gambian children aged 2-4 y not previously vaccinated with a pneumococcal vaccine, was well-tolerated and immunogenic

An Investigation of the Effects of Manufacturing Parameters On Properties of Binderless Boards Produced from Abura (Mitragyna Ciliata) Sawdust

The production of particle boards without the use of synthetic binders is desirable to prevent environmental problems. This study has produced experimental binderless boards from untreated sawdust from Abura wood using a laboratory press. Box-Behnken experimental design was utilized to investigate the effects of the pressing variables including pressure, temperature and pressing time. The density of the boards produced ranged between 523.69 and 738 kg/m3 which was within the range specified for medium density fibreboards . The maximum values for Modulus of Elasticity (MOE), Modulus of Rupture (MOR) and Internal Bonding Strength (IB) were 100.4 MPa, 1.1 MPa and 0.049 MPa, respectively. It was shown that, for the range of factors studied, pressure and the pressing temperature were the more significant factors in determining the density, MOE and IB. This study showed that the sawdust can potentially be used for the production of binderless boards

An Investigation of the Effects of Manufacturing Parameters On Properties of Binderless Boards Produced from Abura (Mitragyna Ciliata) Sawdust

The production of particle boards without the use of synthetic binders is desirable to prevent environmental problems. This study has produced experimental binderless boards from untreated sawdust from Abura wood using a laboratory press. Box-Behnken experimental design was utilized to investigate the effects of the pressing variables including pressure, temperature and pressing time. The density of the boards produced ranged between 523.69 and 738 kg/m3 which was within the range specified for medium density fibreboards . The maximum values for Modulus of Elasticity (MOE), Modulus of Rupture (MOR) and Internal Bonding Strength (IB) were 100.4 MPa, 1.1 MPa and 0.049 MPa, respectively. It was shown that, for the range of factors studied, pressure and the pressing temperature were the more significant factors in determining the density, MOE and IB. This study showed that the sawdust can potentially be used for the production of binderless boards

Stability, Boundedness, and Existence of Periodic Solutions to Certain Third-Order Delay Differential Equations with Multiple Deviating Arguments

The behaviour of solutions for certain third-order nonlinear differential equations with multiple deviating arguments is considered. By employing Lyapunov’s second method, a complete Lyapunov functional is constructed and used to establish sufficient conditions that guarantee existence of unique solutions that are periodic, uniformly asymptotically stable, and uniformly ultimately bounded. Obtained results not only are new but also include many outstanding results in the literature. Finally, the correctness and effectiveness of the results are justified with examples

Determination of Hardness and Tensile Properties of Dissimilar Phase Structured Steel Weld

This work involves the use of submerged arc welding (SAW) technique in joining heat treated steel in alternate arrangement. The selected as-received steel was initially cut, machined and heat treated to develop a conventional microstructure prior to joining operation. All samples were subsequently characterized to investigate the effect of the process on the mechanical behaviors. 3360 Instron Universal Tensile testing machine was used for the tensile properties evaluation; Vickers’ microhardness testing machine was also used for the hardness evaluation at various zones. From the result, it was found that interchanging arrangement of the microstructures during welding yield better combined properties of the ultimate tensile strength, yield strength and with improvement in the strain-to-fracture of some of the samples. The adopted mechanism was also observed to yield better hardness property on the sample. This led to the recommendation of this technique to the oil and gas industry that need to transport their products via the giant water bodies to clients