Moisture Sorption Characteristics of Dehydrated in-shell African Walnut (Tetracarpidium conophorum)

Moisture sorption isotherms are useful thermodynamic tools for determining water interactions within food systems and providing information that can assist in optimizing food processing operations such as drying, mixing, packaging and storage, as well as to maximize retention of quality parameters such as colour, aroma, texture, and nutrient. Moisture sorption isotherm characteristics of African walnut were evaluated at three different temperatures (28, 33 and 38°C) and relative humidity range of 11.20 - 97.00 % using gravimetric method; five mathematical models (GAB, BET, Peleg, Smith and Ferro Fontan) were fitted into the experimental data. Sorption isotherms of the dehydrated walnut gave type II (S-shaped) isotherms according to BET classification. Temperature had significant effect on the equilibrium moisture content (EMC). A nonlinear regression analysis method was used to evaluate the constants of sorption models. The models were evaluated statistically by calculating coefficient of determination (R2), the mean relative percentage error (P) and the reduced chi-square (λ2). The BET model gave the best fit for the obtained data among the tested models with R2 value of 0.9892. Calculated monolayer moisture (Mo) content from BET ranged from 5.018 to 7.922% db for adsorption and 9.842 to 10.143% db for desorption respectively

Effect of optimizing process variables on the quality characteristics of cassava-wheat composite bread

The optimisation of bread-making process can have a positive impact in ramping up the quality characteristics of cassava-wheat bread to  that of whole wheat bread. In this study, a threevariable Box-Behnken design response surface methodology was employed to investigate and optimise independent variables namely cassava flour composition, water content and proofing time in relation to response variables namely dough yield, loaf specific volume and loaf protein of cassava-wheat-composite bread. The data from the experimental design were fitted into second-order regression models and their validity and reliability were confirmed by analysis of variance. Optimal cassava flour composition, water content and proofing time were derived as; 100 g/kg, 589 g/kg and 90 min, respectively. It was revealed that cassava flour composition had the most effect on the quality characteristics of cassava-wheat-composite bread. At constant cassava flour  composition, increase in water content and proofing time had a positive effect on all the studied quality characteristics of cassava-wheat composite bread. Increase cassava flour composition regardless of proofing time and water content had a negative effect on loaf specific volume and protein. This study has provided bread-making conditions which can be utilised in enhancing the consumer acceptability of cassava-wheat composite bread. &nbsp

Herbicidan control of water hyacinth at Ere, Ogun State: implications for fish production

A brief account is given of a pilot demonstration of the chemical control of water hyacinth (Eichhornia crassipes) at Ere (a channel) in Nigeria using the herbicide glyphosphate. Results suggest that there was an increase in the nutrient content of the channel after herbicide application. This implied an upsurge of available food for fish and other aquatic organisms within the channel after the herbicide application. The decaying water hyacinth mass which sinks into the medium is likely to boost nutrient content, promoting the growth of fish and other aquatic animals. It is concluded that herbicidal control of water hyacinth is possible, especially under specialists' management with the conservation of fish and other non-target aquatic organisms alongside improved fish productio

Soil Contamination and Risk Assessments on Selected Dumpsites within the Basement Complex and Sedimentary Formations of Ogun State, South-western Nigeria

The concentrations of inorganic elements in soils of Saje, Ita-Oshin, Premier, and Oke-Diya dumpsites were determined using an X-Ray Fluorescence spectrometer to assess the soil quality through chronological changes with depths. A soil core sampler collects 56 samples at 20, 40, 60, and 80 cm depths. Saje showed high mean concentrations of Ca, K, Fe, Rb, and Ti at all depths, while Oke-Diya revealed high mean concentrations of Ca, K, Fe, Rb, Ti, Mn, Zn, V, Cr, and Ni at all depths. These concentrations were in a closed range suggesting a build-up of elements in the soil profiles. Oke-Diya had the highest pollution index, followed by Saje, and the contaminations were from anthropogenic and geologic sources. The mean concentrations of Fe, Zn, Ni, Mn, Ti, K, and Ca were high at all depths in Ita-Oshin, and in Premier, the mean concentrations of K and Fe were high at all depths. Premier had the lowest pollution index. Ita-Oshin and Premier enrichment factors showed geologic sources. Saje and Oke-Diya revealed unacceptable non-carcinogenic risks for adults and children, and Ita-Oshin and Premier recorded acceptable limits. Saje and Oke-Diya samples had high carcinogenic risks for adults due to Cr, Pb, and As. Elements Cr and As in Ita-Oshin, and Pb in Premier evinced unacceptable carcinogenic risks for adults. Saje, Oke-Diya, and Premier indicated unacceptable carcinogenic risks for children due to Cr. The study showed toxins build-up in the soil system, and the study areas are not suitable for growing crops and sinking water wells for agricultural and domestic uses

Delineation of Leachate Plume Migration Using Electrical Resistivity Imaging on Lapite Dumpsite in Ibadan, Southwestern Nigeria

A geophysical investigation involving 2D resistivity survey was carried out on Lapite dump site that has been in operation since 1998 in ancient city of Ibadan, Southwestern Nigeria. The aim was to map the conductive leachate plume and extent of migration of leachate plumes in the subsurface for possible groundwater contamination. The 2D resistivity survey was carried out using Campus Tigre model resistivity meter with Wenner array configuration of electrode spacing distance ranging from 5 - 25m. A total of nine (9) 2D resistivity profiles with length ranging between 80 and 120 m were conducted within the dump site. A control profile of 2D resistivity survey was also carried out at about 300 m away from the dump site. The obtained resistivity data was interpreted using both RES2DINV and RES3DINV respectively. The 2D and 3D inverse resistivity models of the subsurface revealed the extent of leachate plumes with resistivity values less than 10 Ωm and allowed the location of leachate, clay soil, bedrock and seepage path from the dumpsite to be clearly delineated. There may be possible contamination of shallow groundwater system in the nearest future if proper mitigation measures are not taken into consideration at the dumpsit

Process development for manufacturing of cellular structures with controlled geometry and properties

This study presents experimental results on the behaviour of aluminium alloy metal structures and foams manufactured by lost-wax casting and using 3D printed components for internal structure definition. Results for tensile tests, metallurgical properties, surface quality and geometry tolerances were obtained and discussed. The analysis focused on development geometries, used for adjusting manufacturing parameters and prototype geometries intended for geometrical and mechanical validation. The results are indicative of the viability of the method for producing foam structures suitable for mechanical loading.The authors are grateful to the Portuguese Foundation for Science and Technology (FCT) who financially supported this work, through the project PTDC/EME-PME/115668/2009.info:eu-repo/semantics/publishedVersio