Search results for " Kinetic"
showing 10 items of 416 documents
Ball-milling and AlB2 addition effects on the hydrogen sorption properties of the CaH2 + MgB2 system
2011
Abstract Among the borohydrides proposed for solid state hydrogen storage, Ca(BH 4 ) 2 is particularly interesting because of its favourable thermodynamics and relatively cheap price. Composite systems, where other species are present in addition to the borohydride, show some advantages in hydrogen sorption properties with respect to the borohydrides alone, despite a reduction of the theoretical storage capacity. We have investigated the milling time influence on the sorption properties of the CaH 2 + MgB 2 system from which Ca(BH 4 ) 2 and MgH 2 can be synthesized by hydrogen absorption process. Manometric and calorimetric measurements showed better kinetics for long time milled samples. …
Inhibition by Anandamide and Synthetic Cannabimimetics of the Release of [3H]d-Aspartate and [3H]GABA from Synaptosomes Isolated from the Rat Hippoca…
2004
Cannabinoids (CB) can act as retrograde synaptic mediators of depolarization-induced suppression of inhibition or excitation in hippocampus. This mechanism may underlie the impairment of some cognitive processes produced by these compounds, including short-term memory formation in the hippocampus. In this study, we investigated several compounds known to interact with CB receptors, evaluating their effects on K +-evoked release of [ 3H]d-aspartate ([ 3H]d-ASP) and [ 3H]GABA from superfused synaptosomes isolated from the rat hippocampus. [ 3H]d-ASP and [ 3H]GABA release were inhibited to different degrees by the synthetic cannabinoids WIN 55,212-2; CP 55,940, and arachidonyl-2′- chloroethyla…
Which patients with genotype 1 chronic hepatitis C can benefit from prolonged treatment with the 'accordion' regimen?
2007
The on-treatment virological response to pegylated interferon plus ribavirin therapy is a useful tool in the management of patients with chronic hepatitis C. The time at which hepatitis C virus RNA becomes undetectable by a sensitive PCR assay has a huge impact on the probability of achieving a sustained virological response, particularly in genotype 1 patients, and may be useful in selecting patients for prolonged therapy. Indiscriminate extension of treatment in patients with hepatitis C virus genotype 1 is not beneficial. However, there is a subgroup of patients – the so-called ‘slow responders’ – who benefit from extending treatment from 48 to 72 weeks and can be readily identified afte…
Bromocriptine and Prostatic Carcinoma: Plasma Kinetics, production and Tissue Uptake of3H-Testosterone in Vivo
1978
The influence of the anti-prolactin bromocriptine on plasma kinetics, production rate and tissue uptake of testosterone was investigated in 15 patients with newly diagnosed stages C and D prostatic carcinoma. Bromocriptine was given for 5 days in a daily dose of 15 mg. orally. The studies were performed with the single injection technique using the 2-compartment model. Plasma testosterone, serum prolactin, and luteinizing and follicle-stimulating hormones were determined initially. Blood samples were drawn up to 5 hours after the injection of 3H-testosterone. For tissue studies a transrectal needle biopsy was done 3 hours post-injection. Bromocriptine suppressed prolactin and the endogenous…
Grand canonical rate theory for electrochemical and electrocatalytic systems I: General formulation and proton-coupled electron transfer reactions
2020
A generally valid rate theory at fixed potentials is developed to treat electrochemical and electrocatalytic potential-dependent electron, proton, and proton-coupled electron reactions. Both classical and quantum reactions in adiabatic and non-adiabatic limits are treated. The applicability and new information obtained from the theory is demonstrated for the gold catalyzed acidic Volmer reaction.
Improved Temperature and Emissivity Separation Algorithm for Multispectral and Hyperspectral Sensors
2017
The Temperature and Emissivity Separation (TES) algorithm was originally developed for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). This paper focuses on improving the TES algorithm. The main modification is the replacement of the normalized emissivity module with a new module, which is based on the smoothing of spectral radiance signatures. Smoothing is performed by estimating emissivity using an optimized approximation of the relationship between brightness temperature and emissivity. The improved TES algorithm, which is called Optimized Smoothing for Temperature Emissivity Separation (OSTES), was first tested on simulated data from three different sensors, …
Thermal kinetics for the energy valorisation of polylactide/sisal biocomposites
2018
[EN] The thermal stability and decomposition kinetics of PLA/sisal biocomposites was discussed to evaluate the suitability of their use in energy recovery processes such as pyrolysis and combustion. The influence of the addition of sisal up to 30%wt, the presence of coupling agent, and the atmosphere of operation, i.e. inert or oxidative was discussed by means of multi-rate linear non-isothermal thermogravimetric experiments. All biocomposites showed a mean high heating value of 15 MJ/kg indicating their suitability for energy recovery processes. The thermal requirements of PLA/sisal decomposition were assessed in terms of onset decomposition temperature and apparent activation energy. A mi…
Mathematical modelling and experimental study of straw co-firing with gas
2019
The main goal of the present study is to promote a more effective use of agriculture residues (straw) as an alternative renewable fuel for cleaner energy production with reduced greenhouse gas emissions. With the aim to improve the main combustion characteristics at thermo-chemical conversion of wheat straw, complex experimental study and mathematical modelling of the processes developing when co-firing wheat straw pellets with a gaseous fuel were carried out. The effect of co-firing on the main gasification and combustion characteristics was studied experimentally by varying the propane supply and additional heat input into the pilot device, along with the estimation of the effect of co-firing on…
Role ofH2Oin the thermal annealing of theEγ′center in amorphous silicon dioxide
2009
The model for the annealing of a radiation-induced point defect in silica, the ${\text{E}}_{\ensuremath{\gamma}}^{\ensuremath{'}}$ center, is identified in the temperature range $(150--550)\ifmmode^\circ\else\textdegree\fi{}\text{C}$. Thermal treatments in controlled atmospheres of water vapor, oxygen, or helium of irradiated amorphous silicon dioxide are carried out. Direct experimental evidences that the annealing of the ${\text{E}}_{\ensuremath{\gamma}}^{\ensuremath{'}}$ center is caused by a reaction with diffusing water molecules are found. A rate equation system describing this annealing process is inferred, and its solutions are compared with experimental data to obtain quantitative …
Compensating isothermal calorimeter to investigate the vulcanization of factice
1990
Abstract Sulphur factice is produced from a mixture of a vegetable oil and sulphur for linkage. To start vulcanization, the mixture is heated to temperatures betueen 130 and 150 °C. Within hours or days the temperature increases to about 160 °C and the product solidifies. To investigate the production process and to optimize the reaction, the temperature development was simulated in laboratory-scale experiments and the heat released was measured. In order to investigate the reaction kinetics of the entire vulcanization process, the calorimeter must a11ow the measurement of the mixture in liquid and solid state. The developed compensating calorimeter consists of a hot plate equipped with thi…