Review of simulating four classes of window materials for daylighting with non-standard BSDF using the simulation program Radiance

This review describes the currently available simulation models for window material to calculate daylighting with the program "Radiance". The review is based on four abstract and general classes of window materials, depending on their scattering and redirecting properties (bidirectional scatter distribution function, BSDF). It lists potential and limits of the older models and includes the most recent additions to the software. All models are demonstrated using an exemplary indoor scene and two typical sky conditions. It is intended as clarification for applying window material models in project work or teaching. The underlying algorithmic problems apply to all lighting simulation programs, so the scenarios of materials and skies are applicable to other lighting programs

Solar Thermal Energy In Thimphu, Bhutan - A feasibility study using TRNSYS modeling

Bhutan is one of the highest per capita users of firewood in the world. Firewood and electricity are the most common methods for heating in Bhutan and both methods suffer from drawbacks. Bhutan’s capitol, Thimphu, lies some 2500 meters above sea level and has cold winters with clear skies. These facts are the base for this report’s investigation of the potential to use solar thermal energy to mitigate the use of firewood and electricity for heating. Fieldwork and interviews were carried out in areas in and around Thimphu. Two models were made; one for a typical rural house, heated with firewood, and one for a typical urban apartment complex, heated with electricity. The rural house was modeled as a two story building with one family living on each floor. The urban apartment complex was modeled as a four story building with four apartments on each floor for a total of 16 families living in the building. These models were input into the simulation program TRNSYS. A solar thermal system was optimized for each house based on performance while trying to keep the system as small as possible. The effects of this system on the comfort and energy consumption in the rural and urban model were noted. In the rural case a solar thermal system with a solar collector area of 15 m2 and a tank volume of 0.65 m3 decreased the firewood usage over a year with 50 % while increasing the comfort level. In the urban case a solar thermal system with a solar collector area of 20 m2 and 0.8 m3 per floor, i.e. 5 m2 and 0.2 m3 per apartment, decreased the use of the electric heater with 44 % while increasing the comfort. Several variations to the system and mode of heating were tested and are detailed in the report. It was found that a solar thermal system has a high potential of heating houses in the Thimphu area. The main obstacle for implementing a solar thermal system is its cost

Medien, Interfaces und implizites Wissen

Die Beiträge des Heftes zeigen auf, wie sich das Verhältnis von Medien und implizitem Wissen unter den Bedingungen des Internets der Dinge, im Kontext der Robotik oder in Bezug auf ökonomische Fragen ausgestaltet. Erörtert werden dabei vorrangig Fragestellungen, die an die Interfaces dieser zeitgenössischen Medientechnologien gerichtet werden können. Vor dem Hintergrund medien- und interfacetheoretischer Überlegungen wird aufgezeigt, welche medienwissenschaftlichen Konsequenzen sich für die Analyse dieser kulturellen Phänomene und gesellschaftlichen Felder ergeben

Surviving the surf: The tribomechanical properties of the periostracum of Mytilus sp

We investigated the friction and wear behavior as well as the mechanical properties of the periostracum of Mytilus sp. Tribological properties were determined with a reciprocal sliding microtribometer, while mechanical characterization was performed using a nanoindenter. Measurements were performed in dry and wet conditions. On the dry periostracum we found a low friction coefficient of 0.078 ± 0.007 on the young parts and a higher one of 0.63 ± 0.02 on the old parts of the shell. Under wet, saline, conditions we only observed one average coefficient of friction of 0.37 ± 0.01. Microscopic ex situ analysis indicated that dry periostracum wore rather rapidly by plowing and fatigue, while it exhibited a high wear resistance when immersed in salt water. The Young’s modulus and hardness of the periostracum were also investigated in both dry and wet conditions. Under dry conditions the Young’s modulus of the periostracum was 8 ± 3 GPa, while under wet conditions it was 0.21 ± 0.05 GPa. The hardness of dry periostracum samples was 353 ± 127 MPa, whereas the hardness of wet samples was 5 ± 2 MPa. It was found that, in the wet state, viscous behavior plays a significant role in the mechanical response of the periostracum. Our results strongly indicate that the periostracum can provide an important contribution to the overall wear resistance of Mytilus sp. shell

Activation of Retinal Angiogenesis in Hyperglycemic pdx1(-/-) Zebrafish Mutants

Progression from the initial vascular response upon hyperglycemia to a proliferative stage with neovacularizations is the hallmark of proliferative diabetic retinopathy. Here, we report on the novel diabetic pdx1(-/-) zebrafish mutant as a model for diabetic retinopathy that lacks the transcription factor pdx1 through CRISPR-Cas9-mediated gene knockout leading to disturbed pancreatic development and hyperglycemia. Larval pdx1(-/-) mutants prominently show vasodilation of blood vessels through increased vascular thickness in the hyaloid network as direct developmental precursor of the adult retinal vasculature in zebrafish. In adult pdx1(-/-) mutants, impaired glucose homeostasis induces increased hyperbranching and hypersprouting with new vessel formation in the retina and aggravation of the vascular alterations from the larval to the adult stage. Both vascular aspects respond to antiangiogenic and antihyperglycemic pharmacological interventions in the larval stage and are accompanied by alterations in the nitric oxide metabolism. Thus, the pdx1(-/-) mutant represents a novel model to study mechanisms of hyperglycemia-induced retinopathy wherein extensive proangiogenic alterations in blood vessel morphology and metabolic alterations underlie the vascular phenotype

Reduced Acrolein Detoxification in akr1a1a Zebrafish Mutants Causes Impaired Insulin Receptor Signaling and Microvascular Alterations

Abstract Increased acrolein (ACR), a toxic metabolite derived from energy consumption, is associated with diabetes and its complications. However, the molecular mechanisms are mostly unknown, and a suitable animal model with internal increased ACR does not exist for in vivo studying so far. Several enzyme systems are responsible for acrolein detoxification, such as Aldehyde Dehydrogenase (ALDH), Aldo‐Keto Reductase (AKR), and Glutathione S‐Transferase (GST). To evaluate the function of ACR in glucose homeostasis and diabetes, akr1a1a−/− zebrafish mutants are generated using CRISPR/Cas9 technology. Accumulated endogenous acrolein is confirmed in akr1a1a−/− larvae and livers of adults. Moreover, a series of experiments are performed regarding organic alterations, the glucose homeostasis, transcriptome, and metabolomics in Tg(fli1:EGFP) zebrafish. Akr1a1a−/− larvae display impaired glucose homeostasis and angiogenic retina hyaloid vasculature, which are caused by reduced acrolein detoxification ability and increased internal ACR concentration. The effects of acrolein on hyaloid vasculature can be reversed by acrolein‐scavenger l‐carnosine treatment. In adult akr1a1a−/− mutants, impaired glucose tolerance accompanied by angiogenic retina vessels and glomerular basement membrane thickening, consistent with an early pathological appearance in diabetic retinopathy and nephropathy, are observed. Thus, the data strongly suggest impaired ACR detoxification and elevated ACR concentration as biomarkers and inducers for diabetes and diabetic complications

Impaired Detoxification of Trans, Trans‐2,4‐Decadienal, an Oxidation Product from Omega‐6 Fatty Acids, Alters Insulin Signaling, Gluconeogenesis and Promotes Microvascular Disease

Abstract Omega‐6 fatty acids are the primary polyunsaturated fatty acids in most Western diets, while their role in diabetes remains controversial. Exposure of omega‐6 fatty acids to an oxidative environment results in the generation of a highly reactive carbonyl species known as trans, trans‐2,4‐decadienal (tt‐DDE). The timely and efficient detoxification of this metabolite, which has actions comparable to other reactive carbonyl species, such as 4‐hydroxynonenal, acrolein, acetaldehyde, and methylglyoxal, is essential for disease prevention. However, the detoxification mechanism for tt‐DDE remains elusive. In this study, the enzyme Aldh9a1b is identified as having a key role in the detoxification of tt‐DDE. Loss of Aldh9a1b increased tt‐DDE levels and resulted in an abnormal retinal vasculature and glucose intolerance in aldh9a1b−/− zebrafish. Transcriptomic and metabolomic analyses revealed that tt‐DDE and aldh9a1b deficiency in larval and adult zebrafish induced insulin resistance and impaired glucose homeostasis. Moreover, alterations in hyaloid vasculature is induced by aldh9a1b knockout or by tt‐DDE treatment can be rescued by the insulin receptor sensitizers metformin and rosiglitazone. Collectively, these results demonstrated that tt‐DDE is the substrate of Aldh9a1b which causes microvascular damage and impaired glucose metabolism through insulin resistance