198 research outputs found

    Scenarios for use of biogas for heavy-duty vehicles in Denmark and related GHG emission impacts

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    Biogas may be a promising alternative fuel, mainly for heavy-duty vehicles, that can reduce CO2 emissions via substitution of fossil fuels and further reduce methane emissions from agricultural manure handling. However, as methane is a potent climate gas loss of methane from production to use of biogas is of concern. This study has analysed the potential biomass and biogas production from all Danish organic waste sources under different scenario assumptions for future scenario years. The analysis includes energy demand of the road transportation sector by means of transport and fuel types, and potential use of the limited biogas resource taking into account alternative fuel options available for transportation (electricity, hydrogen, biofuels). Further, the total differences in fuel consumption and GHG emissions due to the replacement of diesel-powered heavy-duty vehicles by gas-powered heavy-duty vehicles are estimated in a well-to-wheel perspective taking into account methane losses

    Microsecond dye regeneration kinetics in efficient solid state dye-sensitized solar cells using a photoelectrochemically deposited PEDOT hole conductor

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    Microsecond dye-regeneration kinetics was observed in efficient solid state dye-sensitized solar cells using photoelectrochemically deposited poly(3,4-ethylenedioxythiophene (PEDOT) hole conductors using transient absorption spectroscopy. The dye-regeneration rate is orders of magnitude slower than the case using the I-/I3- redox couple or commonly used small molecule hole conductor and is attributed to the low dye to PEDOT ratio within the films

    Synthesis of Chiral Polyaniline Films via Chemical Vapor Phase Polymerization

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    Electrically and optically active polyaniline films doped with (1R)-(-)-10-camphorsulfonic acid were successfully deposited on nonconductive substrates via chemical vapor phase polymerization. The above polyaniline∕R-camphorsulfonate films were characterized by electrochemical and physical methods, such as cyclic voltammetry (CV), UV-vis spectroscopy, four-point probe conductivity measurement, Raman spectroscopy, circular dichroism spectroscopy, and scanning electron microscopy. The poly aniline films grown by this method not only showed high electrochemical activity, supported by CV and Raman spectrum, but also exhibited optical activity corresponding to the polymer chains as observed by circular dichroism spectra

    Plasma modification and synthesis of membrane material: a mechanistic review

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    Although commercial membranes are well established materials for water desalination and wastewater treatment, modification on commercial membranes is still necessary to deliver high-performance with enhanced flux and/or selectivity and fouling resistance. A modification method with plasma techniques has been extensively applied for high-performance membrane production. The paper presents a mechanistic review on the impact of plasma gas and polymerization, at either low pressure or atmospheric pressure on the material properties and performance of the modified membranes. At first, plasma conditions at low-pressure such as plasma power, gas or monomer flow rate, reactor pressure, and treatment duration which affect the chemical structure, surface hydrophilicity, morphology, as well as performance of the membranes have been discussed. The underlying mechanisms of plasma gas and polymerization have been highlighted. Thereafter, the recent research in plasma techniques toward membrane modification at atmospheric environment has been critically evaluated. The research focuses of future plasma-related membrane modification, and fabrication studies have been predicted to closely relate with the implementation of the atmospheric-pressure processes at the large-scale

    Conductive Polymer Combined Silk Fiber Bundle for Bioelectrical Signal Recording

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    Electrode materials for recording biomedical signals, such as electrocardiography (ECG), electroencephalography (EEG) and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread), which offer a new biocompatible stress free interface with living tissue in both wet and dry conditions

    Circulating Glucagon 1-61 Regulates Blood Glucose by Increasing Insulin Secretion and Hepatic Glucose Production

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    Glucagon is secreted from pancreatic a cells, and hypersecretion (hyperglucagonemia) contributes to diabetic hyperglycemia. Molecular heterogeneity in hyperglucagonemia is poorly investigated. By screening human plasma using high-resolution-proteomics, we identified several glucagon variants, among which proglucagon 1-61 (PG 1-61) appears to be the most abundant form. PG 1-61 is secreted in subjects with obesity, both before and after gastric bypass surgery, with protein and fat as the main drivers for secretion before surgery, but glucose after. Studies in hepatocytes and in b cells demonstrated that PG 1-61 dose-dependently increases levels of cAMP, through the glucagon receptor, and increases insulin secretion and protein levels of enzymes regulating glycogenolysis and gluconeogenesis. In rats, PG 1-61 increases blood glucose and plasma insulin and decreases plasma levels of amino acids in vivo. We conclude that glucagon variants, such as PG 1-61, may contribute to glucose regulation by stimulating hepatic glucose production and insulin secretion
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