Diurnal and annual mean weather cycles over Nsukka, Nigeria during 2010/2011

This study analyzed the mean diurnal and annual cycles of weather elements over Nsukka using the data for 2010 and 2011. It is found that diurnally the peak/trough values occur as follows: temperature (15/06 hrs), relative humidity (06/15 hrs), atmospheric pressure (10/17 hrs), and wind speed (16/19 hrs). The occurrence of the maximum in temperature prior that of wind speed suggests that the dominant winds over Nsukka may be thermally driven. The mean annual peaks/troughs are viz; temperature (March/August), wind speed (December/October), relative humidity (August/January), rainfall (September/December and January) and atmospheric pressure (July/April). A roughly curvilinear fit is found between the annual rainfall and relative humidity: while rainfall appears insensitive to humidity changes during the drier months, its response tends to be linear during the rainy season.Keywords: Diurnal Cycle, Annual Cycle, Curve Fitting, Weather Modulations, Nsukka Weathe

Concept of Phase Transition Based on Elastic Systematics

The use of elastic constants systematics to describe fundamental properties of engineering materials has made materials science education and its related subjects increasingly important not only for manufacturing engineers but also for mankind at large. In this chapter, we present actual scaling of phase transition-driven considerations, such as martensitic transformation and transformable shape memory formation via elastic constant systematics. The scaling in terms of the simple and polycrystals mechanical stability criteria based on the elastic moduli and an acoustic anisotropy is in good agreement with novel experimental data from the literatures, and further, a long-standing concern in predicting polycrystalline elastic constants was considered beyond the commonly encountered criteria

Hybrid Effect on the Mechanical Properties of Sisal Fiber and E-Glass Fiber Reinforced Polyester Composites

The hybrid effect of incorporating periwinkle shell particles into sisal fiber- and E-glass fiber reinforced polyester composite was studied.  Hybrid composites of sisal/periwinkle shell and E-glass/periwinkle shell were prepared at a fixed fiber to polyester ratio of 30:70 and variable ratios of the two reinforcements namely 30:0, 20:10, 15;15, 10:20, 0:30 by weight.  Experimental samples were produced using the hand lay-up method.  Tensile, hardness and flexural tests were performed on these samples and the results showed that the addition of periwinkle shell particles improved the mechanical properties of sisal fiber reinforced composite while it reduced those of E-glass fiber reinforced polyester composite.  Improvement in strength of the sisal/periwinkle hybrid composite was attributed to the ability of the periwinkle shell particles to transfer load to the sisal fibers in the hybrid composite

Alloy Design and Property Evaluation of Ti-Mo-Nb-Sn Alloy for Biomedical Applications

Ti-Mo alloy containing Nb and Sn were arc melted and composition analyzed by EDX. The XRD analysis indicates that the crystal structure and   mechanical properties are sensitive to Sn concentration. A combination of Sn and Nb elements in synergy hindered formation athermal w phase and significantly enhanced b phase stability. The low elastic modulus and good ductility as observed implied that this alloy can be more suitable for biomedical application than the conventional metallic biomaterials from better mechanical compatibility perspective

Effect of Different Steeping Conditions on the Peroxidase Activities of Some Improved Sorghum Varieties

In order to evaluate the impact of duration and the incorporation or  otherwise of air rest during steeping on the peroxidase activities of  sorghum grains, five improved varieties were studied. Steeping durations used ranged from 0 (raw grains) to 72 hours, in two formats: with air rest and without air rest. Results obtained showed that among the raw grains which were the control experiment, variety SK5912 gave the highest  peroxidase activity, followed by variety KSV 8 while variety CSRO2 had the least peroxidase activity. During steeping, we observed that in almost all cases, higher peroxidase activities were obtained with air rested sorghum grains than those without air rest. In terms of how the different varieties compared during steeping, we found that variety KSV 8 gave the highest peroxidase activity at both with and without air rest regimes in all the steeping periods used. Also, we observed that in all cases, the highest increase in peroxidase expression was obtained during the first 6 hours of steeping, shown by a steep rise of over 50% increase in activity. The other steeping times following the first 6 hours however showed just gradual  increases in peroxidase over the period of sorghum. The major significance of this result is that although increasing duration showed increased  peroxidase activities, such increases were less jumpy than those obtained during the first 6 hours. Therefore, long steeping times may not  necessarily be very beneficial, with the added benefit that costs associated with long steeping durations may be avoided.Key words: Sorghum, cereals, peroxidases, enzymes, steeping, germination, air rest

Changes in catalase activities during malting of some improved Nigerian sorghum grain varieties

The catalase activities of ten germinating improved sorghum varieties were monitored over a 4-day period to determine the effect of malting on them. This was done using standard methods that involved catalase assay at the appropriate experimental intervals. Results obtained showed that the different varieties of sorghum differed in their expression of catalase, a difference that was also reflected across the different stages of the malting process. The highest overall catalase activity (20.54 ± 0.74 U) was given by variety SK5912 after 72 hours of germination followed in second place by that from variety Nafelen (18.65 ± 0.99 U) obtained after steeping. The third and fourth highest value (17.88 ± 1.24 U and 17.08 ± 1.64 U) were given by KSV8 and Boboje after 72 and 48 hours of germination respectively. These values are probably indications that no single stage of malting was best for catalase expression among all the varieties. However, the fact that most of them (varieties ICSV 400, SK5912 and KSV 8, CSRO2 and ICSV III) all expressed their highest catalase activities after 72 hours of germination showed that 72 hours is probably the best germination stage for the elicitation of catalase among sorghum grains. The next best stage should be after 48 hours during which point three varieties (Boboje, NRL 3 and KAT 487) had their highest catalase activities. As a unity, all the sorghum varieties had their lowest catalase expression after 24 hours of germination, followed by those obtained after 96 hours germination.Keywords: catalase, sorghum, malting, peroxidase, cereal enzyme

Analogous seasonal evolution of the South Atlantic SST dipole indices

Two variants of sea-surface temperature (SST) dipole indices for the South Atlantic Ocean (SAO) has been previously described representing: (1) the South Atlantic subtropical dipole (SASD) supposedly peaking in austral summer and (2) the SAO dipole (SAOD) in winter. In this study, we present the analysis of observational data sets (1985–2014) showing the SASD and SAOD as largely constituting the same mode of ocean–atmosphere interaction reminiscent of the SAOD structure peaking in winter. Indeed, winter is the only season in which the inverse correlation between the northern and southern poles of both indices is statistically significant. The observed SASD and SAOD indices exhibit robust correlations (P ≤ 0.001) in all seasons and these are reproduced by 54 of the 63 different models of the Coupled Models Intercomparison Project analysed. Their robust correlations notwithstanding the SASD and SAOD indices appear to better capture different aspects of SAO climate variability and teleconnection

Future changes in seasonal-mean precipitation over West Africa under the representative concentration pathways

This study analysed the future changes in seasonal - mean precipitation over West Africa during the mid (2040 - 2065) twenty first century using the Norwegian Earth System Model version 1 (NorESM1 - M). The NorESM1 - M has ~1.89° x 2.5° horizontal atmospheric resolution and 26 vertical levels. The skill of the model in reproducing the observed seasonal - m ean precipitation distribution was evaluated for the historical period (1980 - 2005) using satellite derived precipitation data from the Global Precipitation Climatology Project. Using three possible future levels of atmospheric greenhouse gas concentrations - the Representative Concentration Pathways (RCPs) of 2.6Wm - 2 , 4.5Wm - 2 and 8.5 Wm - 2 , we calculated the projected changes in seasonal - mean precipitation over West Africa for the mid - twenty first c e n t u r y. The projected changes show that the transition to dry season (September-October-November)will experience the highest amounts of increase. Overall, RCP 4.5 projects higher levels of precipitation change compared to the other two RCPs. This points to a non - linear effect of intensified greenhouse forcing on precipitation over West Africa; suggesting that after a particular level of greenhouse gas concentrations further increase may have little or no effect on the regions precipitation. Keywords : West Africa, Precipitation, Climate Change Projections, NorESM 1 - M, RCP

Exploits, Advances and Challenges in Characterizing Self-Healing Materials

Characterization is an indispensable tool for understanding the structure–property-processing relationship in all material classes. However, challenges in self-healing materials characterization arise from the preparation routes, material types, damage mechanism and applications. Here, the discourse surveys the exploits, advances and challenges encountered within various characterization methods that have been exploited to reveal the damage-restoring processes in some material classes, namely metals, polymers, ceramics, concretes and coatings. Since there is no unified characterization procedure for the different classes of materials displaying self-repairing capabilities, the outcome of this discourse contributes to the advancement of knowledge about understanding self-healing testing procedures. An overview of methods, challenges and prospects toward self-healing property standardization at different length scales has been discussed

Diabatic heating governs the seasonality of the Atlantic Niño

The Atlantic Niño is the leading mode of interannual sea-surface temperature (SST) variability in the equatorial Atlantic and assumed to be largely governed by coupled ocean-atmosphere dynamics described by the Bjerknes-feedback loop. However, the role of the atmospheric diabatic heating, which can be either an indicator of the atmosphere’s response to, or its influence on the SST, is poorly understood. Here, using satellite-era observations from 1982–2015, we show that diabatic heating variability associated with the seasonal migration of the Inter-Tropical Convergence Zone controls the seasonality of the Atlantic Niño. The variability in precipitation, a measure of vertically integrated diabatic heating, leads that in SST, whereas the atmospheric response to SST variability is relatively weak. Our findings imply that the oceanic impact on the atmosphere is smaller than previously thought, questioning the relevance of the classical Bjerknes-feedback loop for the Atlantic Niño and limiting climate predictability over the equatorial Atlantic sector.publishedVersio