62 research outputs found
RELATIONSHIP BETWEEN LIMIT STRAIN AND EFFECT OF TEMPERATURE DESCENT
Owing to fixated interest of global environmental problems, the use of metals increases with light-weighting and recyclability and abundance of resources taken into consideration. Especially, nonferrous metal sheets such as Al, Mg, Ti, or Zn alloys attract attention as practical metal and the expansion of the demand is anticipated as alternative of ferrous material. However, these materials are inferior in the formability at cold press working in comparison with ferrous metals. Therefore, the need of improvement of the formability on these metal sheets is widely-recognized. Investigations with respect to the improvement of formability by temperature descent during working consciously in tensile test have been reported. However, there are ambiguity in the definition of limit strain and uniform strain which regarded as the end of stable deformation region. This paper focuses on the effect of temperature descent by determining these values experimentally and computationally
Programma Groen! Wat je allemaal wel met gras kunt doen:minisymposium grasvalorisatie en -vermarkting
Programma Groen! Wat je allemaal wel met gras kunt doen:minisymposium grasvalorisatie en -vermarkting
In dit document staat het programma van het Minisymposium grasvalorisatie en - vermarkting, en ook een plan van aanpak waarin partijen worden voorgesteld en wat de insteek is achter de samenwerkingsverbanden. Want dit congres is voortgekomen uit een samenwerkingsverband tussen het lectoraat Duurzaam Cooperatief Ondernemen, het kenniscentrum Biobased Economy, het lectoraat van Andre Heeres en de leerstoel van prof dr. E. Heeres van de RUG
Lewis acid-catalyzed depolymerization of soda lignin in supercritical ethanol/water mixtures
The depolymerization of lignin model compounds and soda lignin by super Lewis acidic metal triflates has been investigated in a mixture of ethanol and water at 400 °C. The strong Lewis acids convert representative model compounds for the structure-forming linkages in lignin, namely α-O-4, 5-O-4 (C-O-C ether bridge), and α-1 (methylene bridge). Only the 5-5′ C-C linkage in biphenyl was unaffected under the given reaction conditions. Full conversion of soda lignin was achieved without char formation. Lignin was converted into a wide range of aliphatic and aromatic hydrocarbons. Ethanol was involved in the alkylation of the lignin depolymerization products. These alkylation reactions increased the product yield by inhibiting repolymerization of the products. The resulting organic phase consisted of aliphatic hydrocarbons (paraffins and olefins), aromatic hydrocarbons (extensively alkylated non-oxygenated mono-aromatics, mainly alkylbenzenes as well as mono-aromatic oxygenates, mainly phenolics), condensation products (mainly naphthalenes) and saturated oxygenates (ketones and carboxylic acids). Although complete product analysis was not possible, the data suggest that the dominant fraction of lignin was converted into monomeric units with a small fraction with molecular weights up to 650 g/mol
Pharmacokinetic Modeling of [11C]GSK-189254, PET Tracer Targeting H3 Receptors, in Rat Brain
[Image: see text] The histamine H(3) receptor has been considered as a target for the treatment of various central nervous system diseases. Positron emission tomography (PET) studies with the radiolabeled potent and selective histamine H(3) receptor antagonist [(11)C]GSK-189254 in rodents could be used to examine the mechanisms of action of novel therapeutic drugs or to assess changes of regional H(3) receptor density in animal models of neurodegenerative disease. [(11)C]GSK-189254 was intravenously administered to healthy Wistar rats (n = 10), and a 60 min dynamic PET scan was carried out. Arterial blood samples were obtained during the scan to generate a metabolite-corrected plasma input function. PET data were analyzed using a one-tissue compartment model (1T2k), irreversible (2T3k) or reversible two-tissue compartment models (2T4k), graphical analysis (Logan and Patlak), reference tissue models (SRTM and SRTM2), and standard uptake values (SUVs). The Akaike information criterion and the standard error of the estimated parameters were used to select the most optimal quantification method. This study demonstrated that the 2T4k model with a fixed blood volume fraction and Logan graphical analysis can best describe the kinetics of [(11)C]GSK-189254 in the rat brain. SUV(40–60) and the reference tissue-based measurements DVR(2T4k), BP(ND)(SRTM), and SUV ratio could also be used as a simplified method to estimate H(3) receptor availability in case blood sampling is not feasible
Binding of the Dual-Action Anti-Parkinsonian Drug AG-0029 to Dopamine D-2 and Histamine H-3 Receptors:A PET Study in Healthy Rats
Introduction: Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor dysfunction and a diverse range of nonmotor symptoms. Functional relationships between the dopaminergic and histaminergic systems suggest that dual-action pharmaceuticals like AG-0029 (D-2/D-3 agonist/H-3 antagonist) could ameliorate both the motor and cognitive symptoms of PD. The current study aimed to demonstrate the interaction of AG-0029 with its intended targets in the mammalian brain using positron emission tomography (PET). Methods: Healthy male Wistar rats were scanned with a small-animal PET camera, using either the dopamine D-2/D-3 receptor ligand [C-11]raclopride or the histamine H-3 receptor ligand [C-11]GSK-189254, before and after treatment with an intravenous, acute, single dose of AG-0029. Dynamic [C-11]raclopride PET data (60 min duration) were analyzed using the simplified reference tissue model 2 (SRTM2) with cerebellum as reference tissue and the nondisplaceable binding potential as the outcome parameter. Data from dynamic [C-11]GSK-189254 scans (60 min duration) with arterial blood sampling were analyzed using Logan graphical analysis with the volume of distribution (V-T) as the outcome parameter. Receptor occupancy was estimated using a Lassen plot. Results: Dopamine D-2/3 receptor occupancies in the striatum were 22.6 +/- 18.0 and 84.0 +/- 3.5% (mean +/- SD) after administration of 0.1 and 1 mg/kg AG-0029, respectively. In several brain regions, the V-T values of [C-11]GSK-189254 were significantly reduced after pretreatment of rats with 1 or 10 mg/kg AG-0029. The H-3 receptor occupancies were 11.9 +/- 8.5 and 40.3 +/- 11.3% for the 1 and 10 mg/kg doses of AG-0029, respectively. Conclusions: Target engagement of AG-0029 as an agonist at dopamine D-2/D-3 receptors and an antagonist at histamine H-3 receptors could be demonstrated in the rat brain with [C-11]raclopride and [C-11]GSK-189254 PET, respectively. The measured occupancy values reflect the previously reported high (subnanomolar) affinity of AG-0029 to D-2/D-3 and moderate (submicromolar) affinity to H-3 receptors
Nuclear Power - System Simulations and Operation
At the onset of the 21st century, we are searching for reliable and sustainable energy sources that have a potential to support growing economies developing at accelerated growth rates, technology advances improving quality of life and becoming available to larger and larger populations. The quest for robust sustainable energy supplies meeting the above constraints leads us to the nuclear power technology. Today's nuclear reactors are safe and highly efficient energy systems that offer electricity and a multitude of co-generation energy products ranging from potable water to heat for industrial applications. Catastrophic earthquake and tsunami events in Japan resulted in the nuclear accident that forced us to rethink our approach to nuclear safety, requirements and facilitated growing interests in designs, which can withstand natural disasters and avoid catastrophic consequences. This book is one in a series of books on nuclear power published by InTech. It consists of ten chapters on system simulations and operational aspects. Our book does not aim at a complete coverage or a broad range. Instead, the included chapters shine light at existing challenges, solutions and approaches. Authors hope to share ideas and findings so that new ideas and directions can potentially be developed focusing on operational characteristics of nuclear power plants. The consistent thread throughout all chapters is the system-thinking approach synthesizing provided information and ideas. The book targets everyone with interests in system simulations and nuclear power operational aspects as its potential readership groups - students, researchers and practitioners
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