The development of a solar powered residential heating and cooling system

A solar energy collector design is disclosed that would be efficient for both energy transfer and fluid flow, based upon extensive parametric analyses. Thermal design requirements are generated for the energy storage systems which utilizes sensible heat storage in water. Properly size system components (including the collector and storage) and a practical, efficient total system configuration are determined by means of computer simulation of system performance

Trace metal accumulation in hair and skin of the harbour seal, Phoca vitulina

Skin and hair samples of harbour seals (Phoca vitulina) found dead along the west coast of northern Germany in 1988 were analysed for total mercury, cadmium and lead. Cadmium and lead concentrations were below the detection limit in most skin samples. The mercury content of the hair (median: 23.1 μg g−1 wet wt) was several magnitudes higher than the mercury content of the skin (0.27 μg g−1 wet wt). Mercury concentrations in hair samples were significantly higher than lead concentrations (0.54 μg g−1 wet wt), which significantly exceeded cadmium levels (0.09 μg g−1 wet wt). Female seals revealed lower cadmium concentrations in the hair than male seals. Accumulations of metals with age were observed for cadmium and lead in hair samples and for mercury in skin samples of male seals. A connection between metal accumulation and pigmentation or rather moult was clearly recognizable

Enhancing E-learning using Artifact-Based Collaboration

Given the increased focus on e-learning, educators are interested in finding new ways to incorporate techniques that foster active learning. To leverage the asynchronous nature of e-learning settings and provide collaborative learning opportunities for participants that go beyond mere information exchange, this paper proposes an integrated model of collaboration and elearning. This approach ties together two research streams, namely the distributed e-learning environment research and the information systems collaboration research. Further, descriptive categories of collaboration approaches are presented: solution-based collaboration and artifact-based collaboration. An artifact-based collaborative e-learning tool is developed and discussed with the aim to improve the collaborative, e-learning process

No response? Simulating Fear of Missing Out Experiences to Investigate Relationships with Emotion Regulation, Negative Affect, and Counterfactual-Seeking through Social Media

Fear of missing out (FoMO) is a common experience among young adults characterized by the apprehension that others are having rewarding experiences from which one is absent. The present study investigates the construct of FoMO through simulated experiences in order to clarify the context in which FoMO occurs and to examine its relationship with emotion regulation, counterfactual-seeking, and negative affect. The vignette had a significant effect of increasing feelings of FoMO which was positively associated with difficulties in emotion regulation, counterfactual-seeking, and both regret and disappointment. Feelings of FoMO were significantly greater in the enjoyable task in comparison to the obligatory task despite their social nature

Mapping target signatures via partial unmixing of AVIRIS data

A complete spectral unmixing of a complicated AVIRIS scene may not always be possible or even desired. High quality data of spectrally complex areas are very high dimensional and are consequently difficult to fully unravel. Partial unmixing provides a method of solving only that fraction of the data inversion problem that directly relates to the specific goals of the investigation. Many applications of imaging spectrometry can be cast in the form of the following question: 'Are my target signatures present in the scene, and if so, how much of each target material is present in each pixel?' This is a partial unmixing problem. The number of unmixing endmembers is one greater than the number of spectrally defined target materials. The one additional endmember can be thought of as the composite of all the other scene materials, or 'everything else'. Several workers have proposed partial unmixing schemes for imaging spectrometry data, but each has significant limitations for operational application. The low probability detection methods described by Farrand and Harsanyi and the foreground-background method of Smith et al are both examples of such partial unmixing strategies. The new method presented here builds on these innovative analysis concepts, combining their different positive attributes while attempting to circumvent their limitations. This new method partially unmixes AVIRIS data, mapping apparent target abundances, in the presence of an arbitrary and unknown spectrally mixed background. It permits the target materials to be present in abundances that drive significant portions of the scene covariance. Furthermore it does not require a priori knowledge of the background material spectral signatures. The challenge is to find the proper projection of the data that hides the background variance while simultaneously maximizing the variance amongst the targets

Synthetic metabolic pathways for photobiological conversion of CO2 into hydrocarbon fuel

Liquid fuels sourced from fossil sources are the dominant energy form for mobile transport today. The consumption of fossil fuels is still increasing, resulting in a continued search for more sustainable methods to renew our supply of liquid fuel. Photosynthetic microorganisms naturally accumulate hydrocarbons that could serve as a replacement for fossil fuel, however productivities remain low. We report successful introduction of five synthetic metabolic pathways in two green cell factories, prokaryotic cyanobacteria and eukaryotic algae. Heterologous thioesterase expression enabled high-yield conversion of native fatty acyl-acyl carrier protein (ACP) into free fatty acids (FFA) in Synechocystis sp. PCC 6803 but not in Chlamydomonas reinhardtii where the polar lipid fraction instead was enhanced. Despite no increase in measurable FFA in Chlamydomonas, genetic recoding and over-production of the native fatty acid photodecarboxylase (FAP) resulted in increased accumulation of 7-heptadecene. Implementation of a carboxylic acid reductase (CAR) and aldehyde deformylating oxygenase (ADO) dependent synthetic pathway in Synechocystis resulted in the accumulation of fatty alcohols and a decrease in the native saturated alkanes. In contrast, the replacement of CAR and ADO with Pseudomonas mendocina UndB (so named as it is responsible for 1-undecene biosynthesis in Pseudomonas) or Chlorella variabilis FAP resulted in high-yield conversion of thioesterase-liberated FFAs into corresponding alkenes and alkanes, respectively. At best, the engineering resulted in an increase in hydrocarbon accumulation of 8- (from 1 to 8.5 mg/g cell dry weight) and 19-fold (from 4 to 77 mg/g cell dry weight) for Chlamydomonas and Synechocystis, respectively. In conclusion, reconstitution of the eukaryotic algae pathway in the prokaryotic cyanobacteria host generated the most effective system, highlighting opportunities for mix-and-match synthetic metabolism. These studies describe functioning synthetic metabolic pathways for hydrocarbon fuel synthesis in photosynthetic microorganisms for the first time, moving us closer to the commercial implementation of photobiocatalytic systems that directly convert CO2 into infrastructure-compatible fuels

Time-course global expression profiles of Chlamydomonas reinhardtii during photo-biological H₂ production.

We used a microarray study in order to compare the time course expression profiles of two Chlamydomonas reinhardtii strains, namely the high H₂ producing mutant stm6glc4 and its parental WT strain during H₂ production induced by sulfur starvation. Major cellular reorganizations in photosynthetic apparatus, sulfur and carbon metabolism upon H₂ production were confirmed as common to both strains. More importantly, our results pointed out factors which lead to the higher H₂ production in the mutant including a higher starch accumulation in the aerobic phase and a lower competition between the H₂ase pathway and alternative electron sinks within the H₂ production phase. Key candidate genes of interest with differential expression pattern include LHCSR3, essential for efficient energy quenching (qE). The reduced LHCSR3 protein expression in mutant stm6glc4 could be closely related to the high-light sensitive phenotype. H₂ measurements carried out with the LHCSR3 knock-out mutant npq4 however clearly demonstrated that a complete loss of this protein has almost no impact on H₂ yields under moderate light conditions. The nuclear gene disrupted in the high H₂ producing mutant stm6glc4 encodes for the mitochondrial transcription termination factor (mTERF) MOC1, whose expression strongly increases during -S-induced H₂ production in WT strains. Studies under phototrophic high-light conditions demonstrated that the presence of functional MOC1 is a prerequisite for proper LHCSR3 expression. Furthermore knock-down of MOC1 in a WT strain was shown to improve the total H₂ yield significantly suggesting that this strategy could be applied to further enhance H₂ production in other strains already displaying a high H₂ production capacity. By combining our array data with previously published metabolomics data we can now explain some of the phenotypic characteristics which lead to an elevated H₂ production in stm6glc4

Towards 3D Process Simulation for In-Situ Hybridization of Fiber-Metal-Laminates (FML)

Fiber-metal-laminates (FML) provide excellent fatigue behavior, damage tolerant properties, and inherent corrosion resistance.To speed up manufacturing and simultaneously increase the geometrical complexity of the produced FML parts, Mennecart et al. proposed a new single-step process combining deep-drawing with infiltration (HY-LCM). Although the first experimental results are promising, the process involves several challenges, mainly originating from the Fluid-Structure-Interaction (FSI) between deep-drawing and infiltration. This work aims to investigate those challenges to comprehend the underlying mechanisms. A new close-to-process test setup is proposed on the experimental side, combining deep-drawing of a hybrid stack with a linear infiltration. A process simulation model for FMLs is presented on the numerical side, enabling a prediction of the dry molding forces, local Fiber Volume Content (FVC) within the three glass fiber (GF) interlayers, and simultaneous fluid progression. The numerical results show that the local deformation of the hybrid stack and required forces are predictable. Furthermore, lateral sealing of the hybrid stacks leads to deviations from the intended initially one-dimensional fluid progression. Eventually, the numerical results demonstrate that most flow resistance originates from geometrically critical locations. Future experimental and numerical work will combine these insights to focus on the flow evaluation during deformation and a successful part-level application