Fried sweetpotato user preferences identified in Nigeria and Ghana and implications for trait evaluation

Fried sweetpotato quality is important for variety adoption in West Africa. To inform breeding efforts, the study developed a product profile for sweetpotato chunk fries using mixed qualitative and quantitative methods. Root characteristics, processing attributes, in-mouth attributes and appearance of fried product were critical to final product quality. Raw roots should be hard, have smooth skin and no off-odours. Peeled roots should be hard to slice and not sticky. Stickiness and moist surface indicate high moisture content, associated with excessive oil absorption during frying. Hard to slice roots connote high dry matter. Fried product should be crisp, slightly sugary and mealy, have a uniform colour with brown tint and not be soggy. Crispness, mealiness and short frying time with limited oil absorption may be functions of starch. Understanding starch characteristics and other attributes that contribute to quality fried sweetpotato is critical for breeding sweetpotato genotypes with superior quality for frying.     

Carbon‐Decorated FePt Nanoparticles

FePt magnetic nanoparticles are an important candidate material for many future magnetic applications. FePt exists as two main phases, that is, a disordered face‐centered cubic (fcc) structure, which is generally prepared by chemical methods at low temperatures, and the high‐temperature chemically ordered face‐centered tetragonal (fct) structure. The fcc FePt, with low coercivity but associated with superparamagnetic properties, may find applications as a magnetic fluid or as a nanoscale carrier for chemical or biochemical species in biomedical areas, while fct FePt is proposed for use in ultrahigh‐density magnetic recording applications. However, for both of these applications an enhancement of the intrinsically weak magnetic properties, the avoidance of magnetic interferences from neighbor particles, and the improved stability of the small magnetic body remain key practical issues. We report a simple synthetic method for producing FePt nanoparticles that involves hydrothermal treatment of Fe and Pt precursors in glucose followed by calcination at 900 °C. This new method produces thermally stable spheroidal graphite nanoparticles (large and fullerene‐like) that encapsulate or decorate FePt particles of ca. 5 nm with no severe macroscopic particle coalescence. Also, a low coercivity of the material is recorded; indicative of small magnetic interference from neighboring carbon‐coated particles. Thus, this simple synthetic method involves the use of a more environmentally acceptable glucose/aqueous phase to offer a protective coating for FePt nanoparticles. It is also believed that such a synthetic protocol can be readily extended to the preparation of other graphite‐coated magnetic iron alloys of controlled size, stoichiometry, and physical properties.     

A convergence scheme for over-erased flash EEPROM's usingsubstrate-bias-enhanced hot electron injection

A novel convergence scheme using substrate-bias-enhanced hot electron injection is proposed to tighten the cell threshold voltage distribution after erasure for stacked gate flash EEPROM's. By lowering the drain voltage and increasing the magnitude of the negative substrate bias voltage, the substrate current is reduced but the hot electron gate current is enhanced significantly, and the convergence time is shown to be more than a hundred times shorter than the previous scheme. With the convergence operation performed near the ON-OFF transition region of the cells, the total drain current for all the converged cells is reduced and low power consumption is achieved     

West African sorghum beer fermented with Lactobacillus delbrueckii and Saccharomyces cerevisiae: fermentation by‐products

Physicochemical quality parameters and volatile fermentation by‐products were determined in West African sour sorghum beer (pito) fermented with pure cultures of Lactobacillus delbrueckii and Saccharomyces cerevisiae compared with pito prepared by traditional spontaneous fermentation. Levels of by‐products were also compared with those found in similar beer types. Similar levels of apparent extract, alcohol, pH, lactic acid and bitterness were obtained for pure culture and traditional fermentations, although differences were observed in colour and turbidity. Significant statistical differences were obtained for all of the volatile aroma compounds analysed. The pure culture approach resulted in a higher level of total volatile compounds (353 mg/L) of which higher alcohols accounted for 88%, predominately n‐propanol. The traditional approach had total volatiles of 229 mg/L with 86% higher alcohols but with iso‐amyl alcohol predominating. Ester levels were low in the pure culture beer but with a relatively high level of acetaldehyde. Fermenting pito with pure cultures yielded a product with similar physicochemical quality as traditional pito but with a suggestion of a more pronounced aroma whose impact on the overall product quality will require consumer acceptance and sensory evaluation. © 2019 The Institute of Brewing & Distilling     

Adsorption, synergistic inhibitive effect and quantum chemical studies of ampicillin (AMP) and halides for the corrosion of mild steel in H2SO4

The corrosion inhibition of ampicillin (AMP) and its synergistic combination with halides (KI, KCl and KBr) for the corrosion of mild steel in H₂SO₄ have been investigated using gravimetric, gasometric, thermometric and infrared (IR) methods. The inhibition efficiencies of AMP for the corrosion of mild steel increased with increase in concentration but decreased with rise in temperature. The adsorption of AMP on the mild steel surface was found to obey the Langmuir adsorption isotherm model. The combination of AMP with the halides (KI, KBr and KCl) enhanced the inhibition efficiency and adsorption behavior of the inhibitor indicating synergism. The inhibition efficiency of AMP increased with increasing concentration and the adsorption of the inhibitor was spontaneous. Physical adsorption mechanism has been proposed from the thermodynamic data obtained. There was a significant correlation between the inhibition efficiency of AMP and some quantum chemical parameters (R ² = 0.96) using the quantitative structure–activity relationship (QSAR) method. Some quantum chemical parameters and the Mulliken charge densities on the optimized structure of AMP were calculated using the B3LYP/6-31G (d,p) basis set method to provide further insight into the mechanism of the corrosion inhibition process.     

Impact of tunnel currents and channel resistance on thecharacterization of channel inversion layer charge and polysilicon-gatedepletion of sub-20-Å gate oxide MOSFETs

This paper discusses the limitations on MOSFET test structures used in extracting the polysilicon gate doping from capacitance-voltage (C-V) analysis in strong inversion, especially for ultrathin gate oxides. It is shown that for sub-20-Å oxide MOS devices, transistors with channel lengths less than about 10 μm will be needed to avoid an extrinsic capacitance roll-off in strong inversion. The upper limit of the channel length has been estimated using a new simple transmission-line-model of the terminal capacitance, which accounts for the nonnegligible gate tunneling current and finite channel resistance     

West African sorghum beer fermented with Lactobacillus delbrueckii and Saccharomyces cerevisiae: shelf‐life and consumer acceptance

The fermentation profiles, shelf‐life and consumer acceptance of traditional West African sour sorghum beer (pito) fermented with pure commercial starter cultures of lactic acid bacteria (L. delbrueckii) and yeast (Saccharomyces cerevisiae) were evaluated. The beers from this ‘pure culture’ approach were compared with the spontaneous fermentation of pito wort. Lactic acid formation, pH change and extract utilisation were monitored during fermentation. Lactic acid content was used as a measure of sourness to establish the spoilage level of over‐sourness. Further, regression models relating sourness to the time the drink was kept were used to predict the shelf‐life. Consumer acceptance of the product was evaluated using a novel nine‐point hedonic scale. The pure culture and traditionally fermented beers followed similar lactic acid and fermentation profiles but strain‐specific differences were observed. Similar levels of pH, lactic acid level and extract utilisation were achieved. An improvement in shelf‐life of two days was found over traditionally fermented pito. There was no statistical difference between the two pito products for overall liking and taste. However, there was a preference for the aroma of the pure culture pito. It is suggested that the use of pure cultures will facilitate the scale‐up of pito production. © 2019 The Institute of Brewing & Distilling