DETERMINATION OF PHYTATE CONTENTS IN CASSAVA SAMPLES CULTIVATED IN NIGERIA

Analyses of the phytate and total phosphorus (P) compositions of fourteen different varieties of cassava grown in Federal College of Agriculture, Akure, Nigeria were carried out using standard method of analyses. The samples were separated thus: tuber (head, middle and tail), leaves and stem. The results based on dry weight showed that phytate ranged from 203.8-383.4mg100g-1, (head), 213.0-383.0 mg100g-1 (middle), 213.0-372.8 mg100g-1 (tail), 213-383.5 mg100g-1 (leaves) and 213.0-355 mg100g-1 (stem). The middle of the tubers had highest total P. More than half of the cassava samples had over 70% of their total P linked to phytate. The coefficient of variation in percent (CV %) of all-the samples revealed that there were no great disparity between the parameters measured. The relative high phytate value obtained in this study suggests that the bioavailability of metals in the samples should be adequately processed so that the concern posed by the metal chelation and protein – binding action of phytate would be eliminated

Improved aromatic yield and toluene selectivity in propane aromatization over Zn–Co/ZSM-5: effect of metal composition and process conditions

International audienceIn this report, a catalytic enhanced-conventional process production background was employed to determine the most cost-effective and environmentally friendly techniques to improve the catalytic production of toluene and other aromatic compounds from propane aromatization. 2 wt% of zinc was co-impregnated with 1–3 wt% of cobalt on HZSM-5. Characterizations and analysis showed that catalysts are crystalline and microporous. Propane conversion was carried out at 540 °C, 1200 ml/g-h gas hourly space velocity and atmospheric pressure over Zn–Co/ZSM-5 bimetallic catalysts. Toluene selectivity in the aromatic products was greatly improved and sustained significantly together with other aromatic products. Catalytic conversion of propane and aromatic yield over Zn–Co/ZSM-5 was improved and stabilized due to metallic collaboration on HZSM-5. Aromatic yield averaged 46, 32, and 36%, respectively, for 1–3 wt% Co in Zn–Co/ZSM-5 bimetallic catalyst. Average toluene selectivity in the aromatic products for 12 h time on stream from 60, 50 and 51% for 1–3 wt% Co loading. The threshold loading of cobalt with zinc was 2% above which the general aromatic selectivity declined. A decrease in conversion from 73 to 15% was observed for flowrate increase from 6 to 35 ml min−1 and an increase in aromatic selectivity from 80 to 87%. An increase in temperature of 500–560 °C increased catalytic performance, 32–47% for propane conversion, and 79–86% aromatic selectivity

Predicting the impact of climate change and the hydrological response within the Gurara reservoir catchment, Nigeria

The 2150 km2 transboundary Gurara Reservoir Catchment in Nigeria was modelled using the Water Evaluation and Planning tool to assess the hydro-climatic variability resulting from climate change and human-induced activities from 1989 to 2019 and projected to the future till 2050. Specifically, the model simulated the historic data set and predicted the future runoff. The initial results revealed that monthly calibration/validation of the model yielded acceptable results with Nash–Sutcliff efficiency (NSE), percent bias (PBIAS), and coefficient of determination (R2) values of 0.72/0.69, 0.72/0.67 and 4.0%/1.0% respectively. Uncertainty was moderately adequate as the model enveloped about 70% of the observed runoff. Future predicted runoffs were modelled for climate ensembles under three different representative concentration pathways (RCP4.5, RCP6.5 and RCP8.5). The RCP projections for all the climate change scenarios showed increasing runoff trends. The model proved efficient in determining the hydrological response of the catchment to potential impacts from climate change and human-induced activities. The model has the potential to be used for further analysis to aid effective water resources planning and management at catchment scale

Ground-based and Polar spacecraft observations of a giant (Pg) pulsation and its associated source mechanism

Multi-instrument observations of a Pg pulsation, which occurred on the morning of May 16, 1998, are reported. The wave signature was observed simultaneously on the ground, by the International Monitor for Auroral Geomagnetic Effects (IMAGE) magnetometer network and in the ionosphere by the Doppler Pulsation Experiment (DOPE) high resolution HF Doppler sounder. The wave occurred in the morning sector and possessed an azimuthal wave number, m, of 30±5 with a westward phase propagation. Shortly before the Pg commenced, energetic particle instruments on board the Polar spacecraft detected protons with a non-Maxwellian energy distribution drifting westward toward the location of IMAGE and DOPE. An investigation has been undertaken to determine whether these particles were involved in the wave-particle interaction considered responsible for generating the Pg pulsation. Proton energies of around 7 keV, which occur at the low-energy edge of the unstable distribution (where ∂ƒ/∂W>0), satisfy the drift-bounce resonance relation, ω − mω[subscript d] = Nω[subscript b], for N=1. This result indicates that this particular wave is likely to be the result of a drift-bounce resonance mechanism and that it has an even mode standing wave structure in the magnetosphere. This result is discussed in terms of previous observations of Pgs