INFLUENCE OF THERMAL STRESS RATE ON CHANGES IN ELECTRICAL INSULATING OILS

This work solves the comparison of two different thermal stress times for selected liquid insulation materials based on transformer oils by impedance spectroscopy. Research is focused on actual and progressive liquid insulation materials. The scientific objectives of the experiment are focused on the determination of hypotheses, defined by predictable electrophysical parameters in experimental conditions, which are described in the analysis of the measured results.

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Antithrombin-mediated Inhibition of Factor Vlla-Tissue Factor Complex by the Synthetic Pentasaccharide Representing the Heparin Binding Site to Antithrombin

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650512 ◽

1996 ◽

Vol 76 (01) ◽

pp. 005-008 ◽

Cited By ~ 22

Author(s):

Jean Claude Lormeau ◽

Jean Pascal Herault ◽

Jean Marc Herbert

Keyword(s):

Binding Site ◽

Tissue Factor ◽

Residual Activity ◽

Coagulation Factors ◽

Heparin Binding ◽

Experimental Conditions ◽

First Order ◽

Heparin Binding Site ◽

Coagulant Activity

SummaryWe examined the effect of the synthetic pentasaccharide representing the minimal binding site of heparin to antithrombin on the antithrombin-mediated inactivation of factor Vila bound to tissue factor. This effect was compared to the effect of unfractionated heparin. Using purified recombinant human coagulation factors and either a clotting or an amidolytic assay for the determination of the residual activity of factor Vila, we showed that the pentasaccharide was an efficient antithrombin-dependent inhibitor of the coagulant activity of tissue factor-factor Vila complex. In our experimental conditions, assuming a mean MW of 14,000 for heparin, the molar pseudo-first order rate constants for ATIII-mediated FVIIa inhibition by ATIII-binding heparin and by the synthetic pentasaccharide were found to be similar with respective values of 104,000 ± 10,500 min-1 and 112,000 ± 12,000 min-1 (mean ± s.e.m., n = 3)

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Ageing of thermal insulation materials. Determination of the long-term change in thermal resistance of closed-cell plastics (accelerated laboratory test methods)

10.3403/01884824u ◽

2015 ◽

Cited By ~ 1

Keyword(s):

Laboratory Test ◽

Thermal Resistance ◽

Thermal Insulation ◽

Test Methods ◽

Insulation Materials ◽

Closed Cell ◽

Term Change

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Determination of the resistance to cryogenic spillage of insulation materials

10.3403/30354746 ◽

2018 ◽

Keyword(s):

Insulation Materials

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Determination of the resistance to cryogenic spillage of insulation materials

10.3403/30389209u ◽

2019 ◽

Keyword(s):

Insulation Materials

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Determination of alcohols in mixtures by 19F NMR spectroscopy using hexefluoroacetone reagent

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19821973 ◽

1982 ◽

Vol 47 (7) ◽

pp. 1973-1978 ◽

Cited By ~ 2

Author(s):

Jiří Karhan ◽

Zbyněk Ksandr ◽

Jiřina Vlková ◽

Věra Špatná

Keyword(s):

Standard Deviation ◽

Nmr Spectroscopy ◽

Standard Method ◽

Internal Standard ◽

Internal Standard Method ◽

Concentration Region ◽

Experimental Conditions ◽

Curve Method ◽

Sample Preparation Procedure

The determination of alcohols by 19F NMR spectroscopy making use of their reaction with hexafluoroacetone giving rise to hemiacetals was studied on butanols. The calibration curve method and the internal standard method were used and the results were mutually compared. The effects of some experimental conditions, viz. the sample preparation procedure, concentration, spectrometer setting, and electronic integration, were investigated; the conditions, particularly the concentrations, proved to have a statistically significant effect on the results of determination. For the internal standard method, the standard deviation was 0.061 in the concentration region 0.032-0.74 mol l-1. The method was applied to a determination of alcohols in the distillation residue from an oxo synthesis.

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Software-guided microscale flow calorimeter for efficient acquisition of thermokinetic data

Journal of Flow Chemistry ◽

10.1007/s41981-021-00145-6 ◽

2021 ◽

Author(s):

Timothy Aljoscha Frede ◽

Marlene Dietz ◽

Norbert Kockmann

Keyword(s):

Design Of Experiments ◽

Process Development ◽

Reaction Conditions ◽

Experimental Conditions ◽

Flow Calorimeter ◽

Microscale Flow ◽

Increased Sensitivity ◽

Important Time ◽

Optimal Reaction

AbstractFast chemical process development is inevitably linked to an optimized determination of thermokinetic data of chemical reactions. A miniaturized flow calorimeter enables increased sensitivity when examining small amounts of reactants in a short time compared to traditional batch equipment. Therefore, a methodology to determine optimal reaction conditions for calorimetric measurement experiments was developed and is presented in this contribution. Within the methodology, short-cut calculations are supplemented by computational fluid dynamics (CFD) simulations for a better representation of the hydrodynamics within the microreactor. This approach leads to the effective design of experiments. Unfavourable experimental conditions for kinetics experiments are determined in advance and therefore, need not to be considered during design of experiments. The methodology is tested for an instantaneous acid-base reaction. Good agreement of simulations was obtained with experimental data. Thus, the prediction of the hydrodynamics is enabled and the first steps towards a digital twin of the calorimeter are performed. The flow rates proposed by the methodology are tested for the determination of reaction enthalpy and showed that reasonable experimental settings resulted. Graphical abstract A methodology is suggested to evaluate optimal reaction conditions for efficientacquisition of kinetic data. The experimental design space is limited by thestepwise determination of important time scales based on specified input data.

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Apparent Young’s Modulus of the Adhesive in Numerical Modeling of Adhesive Joints

Materials ◽

10.3390/ma14020328 ◽

2021 ◽

Vol 14 (2) ◽

pp. 328

Author(s):

Kamil Anasiewicz ◽

Józef Kuczmaszewski

Keyword(s):

Numerical Model ◽

Young’S Modulus ◽

Adhesive Joint ◽

Young's Modulus ◽

Precise Determination ◽

Adhesive Joints ◽

Experimental Conditions ◽

Element Simulation ◽

Joint Material

This article is an evaluation of the phenomena occurring in adhesive joints during curing and their consequences. Considering changes in the values of Young’s modulus distributed along the joint thickness, and potential changes in adhesive strength in the cured state, the use of a numerical model may make it possible to improve finite element simulation effects and bring their results closer to experimental data. The results of a tensile test of a double overlap adhesive joint sample, performed using an extensometer, are presented. This test allowed for the precise determination of the shear modulus G of the cured adhesive under experimental conditions. Then, on the basis of the research carried out so far, a numerical model was built, taking the differences observed in the properties of the joint material into account. The stress distribution in a three-zone adhesive joint was analyzed in comparison to the standard numerical model in which the adhesive in the joint was treated as isotropic. It is proposed that a joint model with three-zones, differing in the Young’s modulus values, is more accurate for mapping the experimental results.

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Factors affecting in vitro and in vivo antioxidant effects. Experimental conditions and nature of oxidants determine antioxidant efficacy

Journal of Berry Research ◽

10.3233/jbr-200695 ◽

2021 ◽

pp. 1-9

Author(s):

Etsuo Niki

Keyword(s):

Biological Molecules ◽

Experimental Conditions ◽

Factors Affecting ◽

Beneficial Effects ◽

Multiple Oxidants ◽

Antioxidant Effects

Reactive oxygen and nitrogen species have been implicated in the onset and progression of various diseases and the role of antioxidants in the maintenance of health and prevention of diseases has received much attention. The action and effect of antioxidants have been studied extensively under different reaction conditions in multiple media. The antioxidant effects are determined by many factors. This review aims to discuss several important issues that should be considered for determination of experimental conditions and interpretation of experimental results in order to understand the beneficial effects and limit of antioxidants against detrimental oxidation of biological molecules. Emphasis was laid on cell culture experiments and effects of diversity of multiple oxidants on antioxidant efficacy.

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Application of Bar Adsorptive Microextraction for the Determination of Levels of Tricyclic Antidepressants in Urine Samples

Molecules ◽

10.3390/molecules26113101 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3101

Author(s):

Mariana N. Oliveira ◽

Oriana C. Gonçalves ◽

Samir M. Ahmad ◽

Jaderson K. Schneider ◽

Laiza C. Krause ◽

...

Keyword(s):

Tricyclic Antidepressants ◽

Matrix Effects ◽

Activated Carbons ◽

Process Efficiency ◽

Gas Chromatography Mass Spectrometry ◽

Selected Ion Monitoring ◽

Experimental Conditions ◽

Analytical Methodology ◽

Low Efficiency

This work entailed the development, optimization, validation, and application of a novel analytical approach, using the bar adsorptive microextraction technique (BAμE), for the determination of the six most common tricyclic antidepressants (TCAs; amitriptyline, mianserin, trimipramine, imipramine, mirtazapine and dosulepin) in urine matrices. To achieve this goal, we employed, for the first time, new generation microextraction devices coated with convenient sorbent phases, polymers and novel activated carbons prepared from biomaterial waste, in combination with large-volume-injection gas chromatography-mass spectrometry operating in selected-ion monitoring mode (LVI-GC-MS(SIM)). Preliminary assays on sorbent coatings, showed that the polymeric phases present a much more effective performance, as the tested biosorbents exhibited low efficiency for application in microextraction techniques. By using BAμE coated with C18 polymer, under optimized experimental conditions, the detection limits achieved for the six TCAs ranged from 0.2 to 1.6 μg L−1 and, weighted linear regressions resulted in remarkable linearity (r2 > 0.9960) between 10.0 and 1000.0 μg L−1. The developed analytical methodology (BAμE(C18)/LVI-GC-MS(SIM)) provided suitable matrix effects (90.2–112.9%, RSD ≤ 13.9%), high recovery yields (92.3–111.5%, RSD ≤ 12.3%) and a remarkable overall process efficiency (ranging from 84.9% to 124.3%, RSD ≤ 13.9%). The developed and validated methodology was successfully applied for screening the six TCAs in real urine matrices. The proposed analytical methodology proved to be an eco-user-friendly approach to monitor trace levels of TCAs in complex urine matrices and an outstanding analytical alternative in comparison with other microextraction-based techniques.

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