Surrogate-based multi-point forming process optimization for dimpling and wrinkling reduction

Multi-point forming (MPF) has been gaining attention for use in flexible sheet metal forming, since it is conducive to the manufacture of various shapes. However, discrete punch elements may induce either dimples or wrinkles, resulting in defective products. To address these forming issues, this study aims to eliminate both dimpling and wrinkling by adjusting parameters such as the punch speed, punch pressure (cushion compressive strain ratio), and elastic cushion thickness through multi-objective optimization. Evaluation of dimpling and wrinkling under variation in these three MPF parameters benefits from ordinary Kriging for computational efficiency. Multi-objective optimization with a genetic algorithm is used to determine the Pareto fronts of the dimpling and wrinkling measures, and a technique for order preferences by similarity to ideal solution (TOPSIS) is performed for identifying the best candidate among the Pareto optima. Finally, a dimpling-and-wrinkling-free TOPSIS solution is numerically verified by comparison with results of a full model simulation and experimentally validated by its application to a manufactured product.     

Survival of calicivirus in foods and on surfaces: experiments with feline calicivirus as a surrogate for norovirus

Although there is a large body of evidence incriminating foods as vehicles in the transmission of norovirus, little is known about virus survival in foods and on surfaces. Feline calicivirus was used as a surrogate for norovirus to investigate its survival in representative foods of plant and animal origin and on metal surfaces. Known concentrations of feline calicivirus in a natural fecal suspension were deposited onto lettuce, strawberries, ham, or stainless steel and incubated for 7 days at refrigeration or room temperatures. Virus was recovered at 1-day intervals, and the titers of the virus were determined by plaque assay. Infectious virus was recoverable until day 7 from lettuce, ham, and stainless steel. Statistically higher titers of feline calicivirus (P < 0.05) were recovered from ham under all conditions than from lettuce, strawberries, or stainless steel. These data provide valuable information for epidemiological and monitoring purposes as well as for the development of food processing practices and appropriate strategies to inactivate norovirus and control its transmission via foods and surfaces.     

Carotenoid diversity in tropical-adapted yellow maize inbred lines

Maize is a staple food for millions of people in sub-Saharan Africa where a significant number of people suffer from vitamin A deficiency. Yellow maize contains both pro-vitamin A and nonprovitamin A carotenoids with potential health benefits to humans. An improvement in the concentration of these compounds can have a positive impact on dietary intakes in areas where yellow maize is consumed. An essential first step in breeding yellow maize for enhanced carotenoid concentrations involves an assessment of the carotenoid diversity of adapted maize inbred lines. Trials were thus conducted (i) to explore the genetic variation in carotenoid concentrations among tropical-adapted yellow maize inbred lines, (ii) to assess the potential for concurrent improvement of different carotenoids and (iii) to determine the consistency of carotenoid concentrations in different locations. Seed samples of a large set of lines harvested from four trials grown in one location and a fifth trial grown in two locations were analyzed for carotenoid concentrations using HPLC. The analyses of variance revealed that carotenoid concentrations were not strongly affected by the differences in replications or locations. There were large differences among the tropical-adapted yellow maize inbred lines in lutein, zeaxanthin, β-carotene, β-cryptoxanthin, α-carotene and total pro-vitamin A contents. As significant correlations were observed among carotenoids sharing a single branch of the carotenoid biosynthetic pathway, it should be feasible to increase the levels of multiple carotenoids simultaneously. Principal component analysis on the carotenoid composition of the yellow inbred lines identified some lines with higher levels of all carotenoids formed across both major branches of the carotenoid biosynthetic pathway, and other lines having higher levels of those carotenoids formed under a single major branch of the carotenoid biosynthetic pathway. These indicate that the selection of parental lines with diverse carotenoid profiles may possibly be exploited for genetic improvement of carotenoids in tropical maize.     

Evaluation of Global Water Resources Reanalysis Runoff Products for Local Water Resources Applications: Case Study-Upper Blue Nile Basin of Ethiopia

The increasing availability of global observation datasets, both from in situ and remote sensors, and advancements in earth system models and data assimilation algorithms have generated a number of water resources reanalysis products that are available at global scale and high spatial and temporal resolutions. These products hold great potential for water resources applications, but their levels of uncertainty need to be evaluated at local scale. In this work, we evaluate the runoff product from two multi-model global water resources reanalyses (WRRs), available at 0.5° (WRR1) and 0.25° (WRR2) grid resolutions, which were produced within the framework of a European Union project (eartH2Observe) in the upper Blue Nile basin. Analysis indicates that the recently released WRR2 UniK product exhibits consistently better performance statistics than the earlier coarser-resolution WRR1 and the rest of the WRR2 products at all ranges of temporal and spatial scale evaluated. Streamflow simulations based on gauged rainfall forcing and the locally set hydrological model CREST outperforms all the other products, including UniK. Global hydrological products can be a data source for various water resources planning and management applications in data-scarce areas of Africa. This study cautions against using available global hydrological products without prior uncertainty evaluation.

     

Approaching lean product development using system dynamics:investigating front-load effects

Competing with successful products has become perplexing with several uncertainties and transmutes from time to time as customers’ expectations are
dynamic. That is why manufacturing firms exhaustively strive to look for a better competitive frontier using wellestablished and innovative product development (PD) processes. In this paper, we would like to answer three research questions: (i) What would be the effects of frontloading
in PD? (ii) Can we improve our PD process endlessly? (iii) When is the critical time that the firm should take remedial action for improvements? As a contribution to the vast numbers of improvement methods in new product development (NPD), this paper investigates the effects of front-loading using set-based concurrent engineering (SBCE) on cost and lead time. Models are developed and treated using a system dynamics (SD) approach. We assign a hypothetical upfront investment for SBCE and compare its effects on  total cost and lead time of the development process. From the research, it is found that the total cost of PD is reduced almost by half-although the front loading is higher in order to encompass multiple design alternatives. The total product lead time is reduced by almost 20 %. The model reveals the critical time for improvement of the PD process. We use SD tool (e.g., STELLA) for simulation and visualization of the complex PD model, using SBCE as one of several strategies to frontload activities in the NPD process.     

Design of Active Modified Atmosphere and Humidity Packaging (MAHP) for ‘Wonderful’ Pomegranate Arils

Modified atmosphere packaging (MAP) systems have been shown as beneficial to prolong postharvest life of pomegranate arils. Current application of such system is limited due to a lack of appropriate packaging films which are able to control in-package moisture condensation. Therefore, the aim of this study was to design a MAP system to balance the optimum gas composition with packaging film permeability as well as optimum in-package relative humidity (RH). The following packaging materials design were used: (i) 100% cellulose-based film NatureFlex (NF), (ii) bi-axial-oriented polypropylene (BOPP)-based film PropaFilm (PF), (iii) NF-PF (66:33%) film, and (iv) PF-NF (33:66%) film. The effects of package design on quality attributes of pomegranate arils stored at 10 °C (91?±?2% RH) for 9 days were investigated. Package design had significant (p?≤?0.05) impact in changing the in-package RH and gas composition. The 100% cellulose-based (NF) package created the lowest RH (60–66%) with highest reduction in O₂ concentration, highest total soluble solids (TSS), hardness, colour change, and high bacterial count. However, the 100% BOPP-based (PF) film resulted in highest in-package water vapour condensation and mould growth at the end of storage. The optimized packages using PF-NF and NF-PF films, respectively, maintained quality of pomegranate arils and minimized water vapour condensation. The results indicated that PF packaging film fitted with NF film window was the best to maintain the quality of pomegranate arils.     

Augmenting machine learning for Amharic speech recognition: a paradigm of patient’s lips motion detection

Multimedia Tools and Applications - The method of automatic lip motion recognition is an essential input for visual speech detection. It is a technological approach to demystify people who are hard...     

Tuning the band gap of PbSe quantum dots in glasses by TiO doping

Titanium monoxide (TiO) was added to host glass, which was heat-treated at 520 °C for 10 h to incorporate Ti²⁺ into PbSe quantum dots (QDs) to control their band gaps. Incorporation of Ti²⁺ ions into PbSe QDs was confirmed using electron energy loss spectroscopy analysis. Addition of TiO caused blue-shift of the absorption and photoluminescence (PL) bands of the QDs. Absorption bands moved from 1621 nm at TiO concentration [TiO] = 0.0% to 1418 nm at [TiO] = 0.4 mol%. Average diameters of QDs remained mostly unaffected (i.e., 6.25 ± 0.14 nm at [TiO] = 0.0% to 6.03 ± 0.1 nm at [TiO] = 0.4 mol%). The changes in absorption and PL bands originated from the incorporation of Ti²⁺ ions into PbSe QDs. Band gaps of PbSe QDs increased from 0.76 eV at [TiO] = 0% to 0.88 eV at [TiO] = 0.4 mol%. This simple method to tune the band gap of PbSe QDs has possible applications in optical communication fiber amplifiers, infrared laser sources and saturable absorbers.     

Facile Electron Transfer in Atomically Coupled Heterointerface for Accelerated Oxygen Evolution

An efficient and cost-effective approach for the development of advanced catalysts has been regarded as a sustainable way for green energy utilization. The general guideline to design active and efficient catalysts for oxygen evolution reaction (OER) is to achieve high intrinsic activity and the exposure of more density of the interfacial active sites. The heterointerface is one of the most attractive ways that plays a key role in electrochemical water oxidation. Herein, atomically cluster-based heterointerface catalysts with strong metal support interaction (SMSI) between WMn₂O₄ and TiO₂ are designed. In this case, the WMn₂O₄ nanoflakes are uniformly decorated by TiO₂ particles to create electronic effect on WMn₂O₄ nanoflakes as confirmed by X-ray absorption near edge fine structure. As a result, the engineered heterointerface requires an OER onset overpotential as low as 200 mV versus reversible hydrogen electrode, which is stable for up to 30 h of test. The outstanding performance and long-term durability are due to SMSI, the exposure of interfacial active sites, and accelerated reaction kinetics. To confirm the synergistic interaction between WMn₂O₄ and TiO₂, and the modification of the electronic structure, high-resolution transmission electron microscopy (HR-TEM), X-ray photoemission spectroscopy (XPS), and X-ray absorption spectroscopy (XAS) are used.     

Sponge-based materials for oil spill cleanups: A review

Elimination of leaked oil from aquatic environs has recently gained importance owing to the disasters associated with leakages into marine environments. The need for an environmentally friendly and viable line of action concerning the environs has brought forward numerous affordable, non-toxic, and decomposable materials; further, diverse biomasses for fabricating nano- to micro-scale materials, membranes, and sponges/aerogels have also been incorporated for the elimination and retrieval of oils from water. Moreover, selectivity, sorption capacity, and reusability of these materials after the retrieval of oils are also desired from the viewpoint of sustainability. This review encompasses the recent progress in the field of elimination and retrieval of oil spills using various sponge-based materials.