A tractable approximation of non-convex chance constrained optimization with non-Gaussian uncertainties

Chance constrained optimization problems in engineering applications possess highly nonlinear process models and non-convex structures. As a result, solving a nonlinear non-convex chance constrained optimization (CCOPT) problem remains as a challenging task. The major difficulty lies in the evaluation of probability values and gradients of inequality constraints which are nonlinear functions of stochastic variables. This article proposes a novel analytic approximation to improve the tractability of smooth non-convex chance constraints. The approximation uses a smooth parametric function to define a sequence of smooth nonlinear programs (NLPs). The sequence of optimal solutions of these NLPs remains always feasible and converges to the solution set of the CCOPT problem. Furthermore, Karush–Kuhn–Tucker (KKT) points of the approximating problems converge to a subset of KKT points of the CCOPT problem. Another feature of this approach is that it can handle uncertainties with both Gaussian and/or non-Gaussian distributions.     

Genetic parameters of blood β-hydroxybutyrate predicted from milk infrared spectra and clinical ketosis,and their associations with milk production traits in Norwegian Red cows

The aim of this study was to estimate genetic parameters for blood β-hydroxybutyrate (BHB) predicted from milk spectra and for clinical ketosis (KET), and to examine genetic association of blood BHB with KET and milk production traits (milk, fat, protein, and lactose yields, and milk fat, protein, and lactose contents). Data on milk traits, KET, and milk spectra were obtained from the Norwegian Dairy Herd Recording System with legal permission from TINE SA (Ås, Norway), the Norwegian Dairy Association that manages the central database. Data recorded up to 120 d after calving were considered. Blood BHB was predicted from milk spectra using a calibration model developed based on milk spectra and blood BHB measured in Polish dairy cows. The predicted blood BHB was grouped based on days in milk into 4 groups and each group was considered as a trait. The milk components for test-day milk samples were obtained by Fourier transform mid-infrared spectrometer with previously developed calibration equations from Foss (Hillerød, Denmark). Veterinarian-recorded KET data within 15 d before calving to 120 d after calving were used. Data were analyzed using univariate or bivariate linear animal models. Heritability estimates for predicted blood BHB at different stages of lactation were moderate, ranging from 0.250 to 0.365. Heritability estimate for KET from univariate analysis was 0.078, and the corresponding average estimate from bivariate analysis with BHB or milk production traits was 0.002. Genetic correlations between BHB traits were higher for adjacent lactation intervals and decreased as intervals were further apart. Predicted blood BHB at first test day was moderately genetically correlated with KET (0.469) and milk traits (ranged from ?0.367 with protein content to 0.277 with milk yield), except for milk fat content from across lactation stages that had near zero genetic correlation with BHB (0.033). These genetic correlations indicate that a lower BHB is genetically associated with higher milk protein and lactose contents, but with lower yields of milk, fat, protein, and lactose, and with lower frequency of KET. Estimates of genetic correlation of KET with milk production traits were from ?0.333 (with protein content) to 0.178 (with milk yield). Blood BHB can routinely be predicted from milk spectra analyzed from test-day milk samples, and thereby provides a practical alternative for selecting cows with lower susceptibility to ketosis, even though the correlations are moderate.     

Measurement of caffeine in coffee beans with UV/vis spectrometer

In this research work using UV/vis spectrophotometer the molar decadic absorption coefficients and transitional dipole moment of pure caffeine in water and dichloromethane were obtained at 272 and 274.7 nm. The molar decadic absorption coefficients of caffeine in water and dichloromethane at these wavelengths are 1115 and 1010 m² mol⁻¹, respectively. The calculated values for the transitional dipole moment of caffeine in water and in dichloromethane are 10.40 × 10⁻³⁰ and 10.80 × 10⁻³⁰ C m, respectively. After characterizing caffeine in water and dichloromethane, fast and simple methods were developed that enable to quantify the content of caffeine in coffee beans. The methods helped in extracting caffeine from coffee dissolved in water by dichloromethane, and Gaussian fit was applied to eliminate the possible interference with the caffeine spectra.     

“An apple a day keeps the doctor away”: The potentials of apple bioactive constituents for chronic disease prevention

Apples are rich sources of selected micronutrients (e.g., iron, zinc, vitamins C and E) and polyphenols (e.g., procyanidins, phloridzin, 5′-caffeoylquinic acid) that can help in mitigating micronutrient deficiencies (MNDs) and chronic diseases. This review provides an up-to-date overview of the significant bioactive compounds in apples together with their reported pharmacological actions against chronic diseases such as diabetes, cancer, and cardiovascular diseases. For consumers to fully gain these health benefits, it is important to ensure an all-year-round supply of highly nutritious and good-quality apples. Therefore, after harvest, the physicochemical and nutritional quality attributes of apples are maintained by applying various postharvest treatments and hurdle techniques. The impact of these postharvest practices on the safety of apples during storage is also highlighted. This review emphasizes that advancements in postharvest management strategies that extend the storage life of apples should be optimized to better preserve the bioactive components crucial to daily dietary needs and this can help improve the overall health of consumers.     

Dilemma of roof rainwater quality: applications of physical and organic treatment methods in a water scarce region of Mekelle,Ethiopia

The public health field has built a body of literature showing health benefits from improvements in water quality. However, the connection between roof harvested rainwater and health is not well documented especially in developing countries. Understanding the application of locally available treatment methods provides insight into this problem. This paper reports on experimental investigations where rainwater collected from a typical domestic roof in Mekelle, Ethiopia was treated using Moringa stenopetala seed, sand filter and boiling. The quality of the raw and treated roof harvested rainwater were compared against the Ethiopian and World Health Organization drinking water standards to investigate its suitability as a supplement for potable water supply. The pollutants analysed were total coliforms and turbidity. A significant improvement of turbidity and total coliforms was observed. This implies that application of plant coagulant followed by filtration can sufficiently treat rainwater and can be used as a low-cost treatment option in water scarce areas.     

碳纳米管纱在应力下的压阻效应:现象和影响因素(英文)

碳纳米管因机械应力敏感特性而成为传感器的理想材料。单原子层厚度的石墨烯片卷曲而成的单壁碳纳米管具有大约1 nm的管径。碳纳米管纺丝形成纱,使其能够用于结构组份中。本文研究了碳纳米管纱的几何尺寸、力学性能和准静态应力加载速率对其压阻效应的影响。应力加载速率影响碳纳米管纱的失效机理和机电特性。高应力加载速率导致拉伸强度的增加和正压阻效应,而低应力加载速率引起较高的应力失效与负压阻效应。碳纳米管纱的压阻传感器系数随应力加载速率基本不变,但其对于应力水平和碳纳米管纱的几何尺寸具有高度依赖性。作为传感器所需的线性压阻关系在高应力加载速率下相关系数为0.995,而在低应力加载速率下相关系数只有0.832。     

Cumulative impacts of river engineering,Mississippi and Lower Missouri rivers

The goal of this study was to construct a large, data‐rich model to test hydrological responses to engineering modifications on over 3200 km of the Mississippi and Lower Missouri Rivers. We compiled model explanatory variables from a geospatial database quantifying construction of all bridges, wing dikes, bendway weirs, levees, artificial meander cutoffs, channel constriction and navigational dams over the past 100–150 years. Response variables were derived from 68 rated and un‐rated hydrologic stations in the study area, with responses analysed across a range of discharges from within‐channel flows up to moderate floods. Correlation analysis, multiple linear regression and stepwise regression analyses document strong and consistent responses to construction history, both in individual reach‐scale models and systemwide. Meander cutoffs are associated with degradation and acceleration of flow that has reduced stages across the full discharge range. Navigational dams on the Upper Mississippi River increased low‐flow stages and flood levels to a lesser extent, with little or no post‐dam change. One of the strongest signals was the hydrologic response to wing‐dike construction, which resulted in large back‐water increases in stage upstream of wing dikes and mixed effects downstream, including the overlapping effects of incision and velocity losses. Levees were associated with local flow concentration, overbank storage loss and floodplain conveyance loss depending on reach‐scale conditions. The results presented here (1) quantify incremental and cumulative hydrologic responses to a range of engineering activities and (2) provide an empirical tool for verifying and assessing hydraulic and other models of river‐system change. Copyright © 2009 John Wiley & Sons, Ltd.     

Fluorinated Pentafulvalene-Fused Hole-Transporting Material Enhances the Performance of Perovskite Solar Cells with Efficiency Exceeding 23%

Organic small molecular materials with coplanar π-conjugated system as HTMs in perovskite solar cells (PSCs) have attracted considerable attention due to their high charge transport capability and thermal stability. Herein, three novel pentafulvalene-fused derivatives with or without fluorine atoms incorporated ( YSH-oF and YSH-mF and YSH-H , respectively) are designed, synthesized, and applied as hole-transporting materials (HTMs) in PSCs fabrication. The fluorinated HTMs, YSH-oF and YSH-mF , exhibited higher hole mobility and better charge extraction at the perovskite/HTM interface than non-fluorinated one do, presumably due to the closer intermolecular π–π packing interactions. As a result, small-area (0.09 cm²) PSCs made with YSH-oF and YSH-mF achieved an impressive power conversion efficiency (PCE) of 23.59% and 22.76% respectively, with negligible hysteresis, in contrast with the 20.57% for the YSH-H -based devices. Furthermore, for large-area (1.00 cm²) devices, the PSCs employing YSH-oF exhibited a PCE of 21.92%. Moreover, excellent long-term device stability is demonstrated for PSCs with F-substituted HTMs ( YSH-oF and YSH-mF ), presumably due to the higher hydrophobicity. This study shows the great potential of fluorinated pentafulvalene-fused materials as low-cost HTM for efficient and stable PSCs.     

Synergistic strengthening of composite films by crosslinking graphene oxide reinforcement and poly(vinyl alcohol) with dicarboxylic acids

High‐strength plastic materials with excellent biodegradability, non‐toxicity and economically wide availability are in high demand. Herein, we demonstrate graphene oxide (GO) composite of poly(vinyl alcohol) (PVA) as a potential bioplastic material by chemical crosslinking. For a potential bioplastic material, PVA has to be addressed for its high water absorbing capacity along with improvement in tensile strength and thermal stability. These issues were addressed by enhancing the interfacial binding between PVA and GO, covalent bonds between the two being introduced by crosslinking with dicarboxylic acids, namely succinic acid (SuA) and adipic acid (AdA). Crosslinking of neat PVA with dicarboxylic acids also resulted in enhanced swelling resistance and thermal stability. The greatest improvement in tensile strength and swelling resistance was observed for a GO crosslinked with diacids due to the synergistic effect of reinforcement and crosslinking. Improvements of 225 and 234% in the tensile strength of PVA (31.19 MPa) were observed for 5% GO–PVA samples crosslinked with 6.25 mmol AdA and 7.5 mmol SuA, respectively. For the same samples, water uptake was 44 and 29%, respectively, compared to the non‐crosslinked PVA (359%). © 2017 Society of Chemical Industry     

Genetic variation for grain mineral content in tropical-adapted maize inbred lines

Increasing the concentrations of Fe and Zn in staple food crops through breeding has been proposed as one strategy to minimize the adverse effects of widespread mineral deficiencies in humans. This approach requires the presence of adequate genetic differences in concentrations of grain minerals for improvement. Eight trials involving different sets of tropical maize inbred lines adapted to the lowlands and mid-altitudes were, therefore, evaluated for concentrations of grain Fe, Zn and other minerals in two locations. The combined analyses of variance showed significant variation in concentrations of grain minerals among inbred lines in each trial, which was always greater than the variation caused by locations and line × location interactions. The line × location interaction had no significant effect on concentrations of Fe, Zn, Cu, Mg and P in at least three trials of lowland inbred lines. The line × location interaction also did not significantly affect the concentrations of any minerals, except S, in at least three trials of mid-altitude inbred lines. The best-inbred lines identified from each trial had 32–78% more Fe and 14–180% more Zn than their trial average. The first two principal component axes, which accounted for 55–64% of the total variation in kernel mineral concentrations, stratified the inbred lines in each trial into four groups based on differences in their grain mineral compositions. None of the correlations of Fe and Zn with Mn, Cu, Ca, Mg, K, P and S was significant and negative in the various trials, while the correlations of Fe with Zn were positive and significant (r = 0.55 to r = 0.68, p < 0.0001) in almost all the trials. These results suggest that a genetic potential exists for concurrent improvement of Fe and Zn without lowering the concentrations of other grain minerals in maize.