Thermal Performance of Vacuum Insulated Window Shutter Systems

Windows are a major area of heat loss in buildings losing up to 10 times more energy compared to other building elements. Thermal shutters are used to improve the energy performance of windows in both hot and cold climatic conditions. The performance of thermal shutters however greatly depends on the thermal insulation and construction detailing, specifically cold-bridging, through the shutter, as well as between the shutter and window frames. This study evaluates the effects of cold-bridging, trickle ventilation and the size of the air cavity, between the vacuum insulated shutter and the window, on the performance of window thermal shutters. Thermal simulations are conducted in VOLTRA (Thermal analysis software) to assess the conditions. The results indicate that although thermal shutters reduce heat-loss through windows, their performance could be significantly affected by cold-bridging by up to 90%. The additional thermal resistance due to the air cavity and the ventilation through the trickle vent appeared to be much less significant compared to the effects of thermal bridging

LIVE HOG AND PORK IMPORTS: PAST AND PROJECTED CONSEQUENCES FOR THE U.S. PORK SECTOR

The U.S. pork sector is modeled to simulate the effects of alternative import levels on prices, production, consumption, farm receipts, and consumer expenditures. Over the 1983-1985 period, producers annually received $600 million less due to increasing imports than if imports had remained at the 1979-1982 average. Farm prices and slaughter were lower by$2.21 per hundredweight and .1 million head annually, respectively. Four simulations reflecting alternative import paths over the period 1986-1992 were examined. With lower imports (relative to current levels), production and farm prices rise significantly in the long run; consumers purchase less and pay more.International Relations/Trade,

Metabolic modeling and analysis of the metabolic switch in Streptomyces coelicolor

Background The transition from exponential to stationary phase in Streptomyces coelicolor is accompanied by a major metabolic switch and results in a strong activation of secondary metabolism. Here we have explored the underlying reorganization of the metabolome by combining computational predictions based on constraint-based modeling and detailed transcriptomics time course observations. Results We reconstructed the stoichiometric matrix of S. coelicolor, including the major antibiotic biosynthesis pathways, and performed flux balance analysis to predict flux changes that occur when the cell switches from biomass to antibiotic production. We defined the model input based on observed fermenter culture data and used a dynamically varying objective function to represent the metabolic switch. The predicted fluxes of many genes show highly significant correlation to the time series of the corresponding gene expression data. Individual mispredictions identify novel links between antibiotic production and primary metabolism. Conclusion Our results show the usefulness of constraint-based modeling for providing a detailed interpretation of time course gene expression data

Drag and diffusion coefficients of BB mesons in hot hadronic matter

The drag and diffusion coefficients of a hot hadronic medium consisting of pions, kaons and eta using open beauty mesons as a probe have been evaluated. The interaction of the probe with the hadronic matter has been treated in the framework of chiral perturbation theory. It is observed that the magnitude of both the transport coefficients are significant, indicating substantial amount of interaction of the heavy mesons with the thermal bath. The results may have significant impact on the experimental observables like the suppression of single electron spectra originating from the decays of heavy mesons produced in nuclear collisions at RHIC and LHC energiesComment: 5 pages and 3 fig

Perovskite solar cells: short lifetime and hysteresis behaviour of current–voltage characteristics

Perovskite solar cells have shown an impressive efficiency improvement over the past ~ 10 years achieving ~ 23% to date. However, the lifetime and instability of device characteristics are real issues to understand and solve before scaling up and commercialisation of these devices. Researchers have attempted to understand the hysteresis behaviour of current–voltage (I–V) curves in terms of mechanisms such as migration of several ions across the device and the effects of electronic defects during measurements. This review contributes to this scientific debate by presenting similar behaviour observed and reported for devices based on inorganic semiconductors. In established inorganic semiconductor thin film solar cells, both short lifetime and hysteresis have been observed, described and understood in terms of effects of numerous electronic defect levels. Therefore, the situation may be very similar and it is important to identify and reduce defects to remove this un-desirable behaviour from perovskite solar cells. After considering the wealth of experimental results reported in the literature, the conclusion made is the dominating mechanism of I–V hysteresis is due to electronic defects available within the device structure. Suggestions have been made for potential researchers to experimentally investigate the phenomenon in order to finally put an end to this debate. As the defect levels and their concentrations are reduced, the initial efficiency, stability and the lifetime of perovskite solar cells should improve further, beyond the current situation

Microbial imbalance in inflammatory bowel disease patients at different taxonomic levels

Background Inflammatory bowel disease (IBD), is a debilitating group of chronic diseases including Crohn’s Disease (CD) and ulcerative colitis (UC), which causes inflammation of the gut and affects millions of people worldwide. At different taxonomic levels, the structure of the gut microbiota is significantly altered in IBD patients compared to that of healthy individuals. However, it is unclear how these IBD-affected bacterial groups are related to other common bacteria in the gut, and how they are connected across different disease conditions at the global scale. Results In this study, using faecal samples from patients with IBD, we show through diversity analysis of the microbial community structure based on the 16S rRNA gene that the gut microbiome of IBD patients is less diverse compared to healthy individuals. Furthermore, we have identified which bacterial groups change in abundance in both CD and UC compared to healthy controls. A substantial imbalance was observed across four major bacterial phyla including Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria, which together constitute >98% of the gut microbiota. Next, we reconstructed a bacterial family co-abundance network based on the correlation of abundance profiles obtained from the public gut microbiome data of >22000 samples of faecal and gut biopsies taken from both diseased and healthy individuals. The data was compiled using the EBI metagenomics database [1]. By mapping IBD-altered bacterial families to the network, we show that the bacterial families which exhibit an increased abundance in IBD conditions are not well connected to other groups, implying that these families generally do not coexist together with common gut organisms. Whereas, the bacterial families whose abundance is reduced or did not change in IBD conditions compared to healthy conditions are very well connected to other bacterial groups, suggesting they are highly important groups of bacteria in the gut that can coexist with other bacteria across a range of conditions. Conclusions IBD patients exhibited a less diverse gut microbiome compared to healthy individuals. Bacterial groups which changed in IBD patients were found to be groups which do not co-exist well with common commensal gut bacteria, whereas bacterial groups which did not change in patients with IBD were found to commonly co-exist with commensal gut microbiota. This gives a potential insight into the dynamics of the gut microbiota in patients with IBD