Does incorporation of cowpea-maize residue mixes influence nitrous oxide emission and mineral nitrogen release in a tropical luvisol?

In the face of climate change, quantification of the emission of nitrous oxide from soils in relation to sufficient N availability for crop uptake has assumed much significance. This study used the ¹⁵N stable isotope technique, under controlled laboratory conditions, to quantify the interactive effect on and relative contributions of the component species to N₂O emission and mineral N dynamics in a tropical luvisol incorporated with different rates of cowpea-maize residue mixtures. The results show that increasing the maize residue proportion in the mixture significantly decreases N₂O emission compared to the sole cowpea incorporation but increases mineral N concentration compared to sole maize residue incorporation. It is concluded that mixing low C:N ratio cowpea residue with high C:N ratio maize residue has potential for N management in tropical legume-cereal intercropping systems with the view to minimizing N₂O emission while making N available for crop uptake.     

Microbial modification of the texture of grated cassava during fermentation into akyeke

The traditional akyeke inoculum and fermenting akyeke, an indigenous cassava product, were investigated to identify microbial species responsible for the modification of cassava texture during fermentation. Both field and laboratory samples were examined and only some cultures isolated on Plate Count Agar and Malt Extract Agar were found to be capable of causing a softening of cassava tissue when plated directly on sterile cassava slices. The cassava tissue softening isolates on PCA were tentatively identified as Bacillus subtilis and isolates on MEA as Candida tropicalis and Zygosacchromyces florentinus. The population of B. subtilis in the laboratory sample of inoculum was found to be 2.4 x 10(9) cfu g(-1) and increased during dough fermentation from 1.1 x 10(7) to 3.5 x 10(9) cfu g(-1) after 96 h. C. tropicalis was present in the inoclum at 3.0 x 10(9) cfu g(-1) and increased during dough fermentation from 3.2 x 10(6) to 6.9 x 10(7) cfu g(-1) whilst Z. florentinus was present in the inoclum at 9.1 x 10(8) cfu g(-1) and increased from 8.1 x 10(5) to 7.5 x 10(6) cfu g(-1) during dough fermentation.     

Generating decision maker preferred production plans

Abstract

Generating a mine plan that is acceptable by the decision maker (eg, mine manager) is a regular problem for the mining analyst (eg, mining engineer). This problem looms larger when the decision maker does not guide the process. This phenomenon is typical of single objective and single criterion-oriented optimisation methodologies which are not designed to involve the decision maker. The process of generating a decision maker's preferred production plan involving multiple objectives and multiple decision parameters is demonstrated here using PARETO OPTIMAL STOCHASTIC SERIAL DYNAMIC PROGRAMMING. The process requires the mining analyst to generate a superior set (pareto set) of alternatives out of the usually numerous set of feasible alternatives. The decision maker then conducts a careful study of the pareto set and declares his level of preferences for the objectives. Finally, the mining analyst generates the production plan preferred by the decision maker.     

Speciation of animal fat: Needs and challenges

The use of pork fat is a concern for Muslims and Jews, who for religious reasons avoid consuming anything that is pig-derived. The use of bovine materials, including beef fat, is prohibited in Hinduism and may also pose a risk of carrying the infectious agent for bovine spongiform encephalopathy. Vegetable oils are sometimes adulterated with animal fat or pork fat with beef fat for economic gain. The development of methods to determine the species origin of fat has therefore become a priority due to the complex and global nature of the food trade, which creates opportunities for the fraudulent use of these animal fats as food ingredients. However, determining the species origin of fats in processed foods or composite blends is an arduous task as the adulterant has a composition that is very similar to that of the original fat or oil. This review examines some of the methods that have been developed for fat speciation, including both fat-based and DNA-based methods, their shortcomings, and the need for additional alternatives. Protein-based methods, specifically immunoassays targeting residual proteins in adipose tissue, that are being explored by researchers as a new tool for fat speciation will also be discussed.     

Numerical Modeling of Helical Static Mixers for Water Treatment

To improve the understanding of how static mixers work and how to better utilize them in environmental engineering (or, specifically, drinking water treatment), a numerical model for simulating turbulent flows in helical static mixers is developed. The model solves the three-dimensional, Reynolds-averaged Navier-Stokes equations, closed with the k-ω turbulence model, using a second-order-accurate finite-volume numerical method. Numerical simulations are carried out for a two-element helical static mixer, and the computed results are analyzed to elucidate the complex, three-dimensional features of the flow. The results show that the flow field within the mixer is characterized by the presence of pockets of reversed flow and the growth and interaction of strong longitudinal vortices. As an example of the kind of practical insights that can be gained from such detailed three-dimensional computations, the simulated flow field is used to investigate two quantities that are often used to characterize mixing within a static mixer and to discuss the merits of these quantities for coagulant mixing in drinking water treatment.     

Brazing of pressureless-sintered SiC using Ag-Cu-Ti alloy

A pressureless-sintered SiC was brazed to itself using Ag-Cu alloy foil to which titanium had been added. The results obtained revealed the following. (i) Increasing the titanium addition to the base metal from 2 to 8 wt % improved the wettability greatly, but the bonding generally became weaker. (ii) With 2 wt % Ti addition, a reaction layer about 1 m thick was formed, regardless of which brazing temperature was used, while bond strength reached was over linearly with temperature. The maximum room-temperature bend strength reached was over 350 MPa. (iii) In the case of the alloy with only 2 wt % Ti additive, bonding was greatly influenced not only by improvement of the wettability at high temperatures and longer holding times, but also the composition and thickness of the resultant reaction layer.     

How slow is labour-based technology compared with equipment-intensive technology?

The technical content and the rate of progress for a total of 34 donor-funded feeder road projects executed between 1993 and 1997 were analysed. The results show that:

Assessing the Effects of Sunlight on the Photooxidation of Tropical Oils with Experimental and Computational Approaches

This study aims to investigate the influence of high-intensity sunlight radiation on the photooxidation of tropical oils (TO). Coconut oil (CNO), palm oil (PO), and palm kernel oil (PKO) were chosen for determining the indicators of photooxidation when exposed to and in the absence of sunlight for 7 weeks. The results showed a significant (P < 0.05) increase in free fatty acid (FFA) levels and peroxide value (PV) when the TO were exposed to sunlight. The iodine value and color content decreased significantly (P < 0.05) due to the decomposition of unsaturated FFA owing to the breaking down of the π-bonds and the degradation of color pigments during photooxidation. Fourier transform infrared spectroscopy (FTIR) analysis showed strong vibrational absorptions at 1721 and 3505 cm⁻³, 1720 and 3560 cm⁻³, and 1721 and 3554 cm⁻³ for the CNO, PO, and PKO samples exposed to sunlight, respectively. These bands can be attributed to the presence of secondary oxidation products, which were absent in the TO that were not exposed to sunlight. A simulation was performed to support the FTIR results, which also indicated peaks from the secondary oxidation products at 1744 and 3660 cm⁻³. The study also revealed that the rate of photooxidation was different for each TO. The rate of oxidation followed the order PO > PKO > CNO. In contrast, no notable changes were observed in the TO kept away from sunlight. These results suggest that exposing TO to sunlight influences their oxidation stability and quality.     

ICT Capacity as the Investment and Use of ICT: Exploring its Antecedents in Africa

In this paper, we investigate the extent to which economic, human development endowment, political, and population conditions influence information and communication technology (ICT) capacity in African nations using ordinary least squares. We use five variables to measure ICT capacity: ICT expenditure as a percent of GDP (ICTE), ICT expenditure per capita in US dollars (ICTEP), investment in telecoms with private participation (INVTE), Internet users per 100 people (INTUS), and mobile phone subscribers per 1000 people (MOBPS). Unlike ICT adoption and diffusion that focuses on the use of ICT, ICT capacity measures public and private investments in ICT and the use of ICT. The results indicate that ICT capacity of a nation increases with increased (high) corruption index. Further, ICT investment by the private sector depends mainly on human development factors and is not influenced by the perceptions of corruption about a nation. We present theoretical and practical implications of the findings for developing nations in general and African nations in particular.