Absorption of water in silicon gel

Water is an important enemy of an electric insulation system. Water vapour can be absorbed by electrical insulation materials (liquids or solid) and migrate in between the materials to achieve the same relative humidity equilibrium everywhere. Water can reduce withstand voltage of the insulation liquid, initiate partial discharges in wet solids and increase dielectric losses in solids like epoxies, gels, PCB cards and produce dielectric heating. In insulation liquid filled system the water content of the liquid should never be allowed to reach saturation. One failure scenario is when typical oil with significant water content is cooled to a temperature where the water content is above the saturation content, and then water will precipitate and may condensate at cold insulating gaps and give breakdown due to electric field enhancement. Gel samples were investigated in climate chambers in various conditions of humidity and temperature until an equilibrium was reached. Diffusion and absorption of water were measured at different intervals. The aim of the study was to find an appropriate technique/methodology to follow the absorption of moisture in gel as a function of time. Several techniques were tested to determine the moisture content in the gel such as Karl Fischer, weight differences measurement, freeze drying and capacitive relative humidity sensors giving contrasted results. The weight difference method showed “anomaly” indicating bound water, even after equilibrium (measured with the other methods) was reached the weight continued to increase. The use of humidity sensors covered by gel appears to be the most reliable technique.Absorption of water in silicon gelacceptedVersio

Genetic variation in transferrin as a predictor for differentiation and evolution of caribou from eastern Canada

Polycrylamide gel electrophoresis was used to analyse tranferrrin variation in caribou populations from Manitoba, Ontario, Québec/Labrador, and from Baffin Island, Northwest Territories in eastern Canada. The transferrin allele frequencies in these populations were compared with those previously reported for Canadian barren-ground caribou, Rangifer tarandus groenlandicus, Alaska caribou, R.t. grand, Peary caribou, R.t. pearyi, Svalbard reindeer, R.t. pla-tyrhynchus, and Eurasian tundra reindeer, R.t. tarandus. A total of twenty different alleles was detected in the analysed material, considerable genetic heterogeneity being detected among regions. Three alleles that were relatively common in caribou from Ontario, Manitoba and Québec/Labrador, were not present in R.t. grand, R.t. pearyi, R.t. tarandus or R.t. platyrhynchus, and present only at very low frequencies 'm R.t. groenlandicus. These findings, together with genetic identity analyses, suggest that the caribou in Manitoba, Ontario, and Québec/Labrador are mainly of the R.t. caribou type, and that little interbreeding has occurred with other subspecies. The large genetic distance in the transferrin locus between R.t. caribou and other subspecies of reindeer/caribou suggests that, during the Wisconsin glaciation the ancestral populations of R.t. caribou survived in a refugium different from that of the ancestral populations of the other subspecies. Significant genetic differences between Baffin Island caribou and all other populations were mainly due to the presence of one allele that was in high frequency in Baffin Island caribou, but that was absent, or present in very low frequencies, in all other reindeer/caribou populations. The genetic differences between Baffin Island caribou and the other subspecies were greater than the differences between several of the currently recognized subspecies

Direct measurement of the flow field around swimming microorganisms

Swimming microorganisms create flows that influence their mutual interactions and modify the rheology of their suspensions. While extensively studied theoretically, these flows have not been measured in detail around any freely-swimming microorganism. We report such measurements for the microphytes Volvox carteri and Chlamydomonas reinhardtii. The minute ~0.3% density excess of V. carteri over water leads to a strongly dominant Stokeslet contribution, with the widely-assumed stresslet flow only a correction to the subleading source dipole term. This implies that suspensions of V. carteri have features similar to suspensions of sedimenting particles. The flow in the region around C. reinhardtii where significant hydrodynamic interaction is likely to occur differs qualitatively from a "puller" stresslet, and can be described by a simple three-Stokeslet model.Comment: 4 pages, 4 figures, accepted for publication in PR

Liquid insulation of IGBT modules: Long term chemical compatibility and high voltage endurance testing

To facilitate operation of power electronics for subsea operation at ambient pressure components have to be submerged in a liquid. Equipment and schemes for testing of long term properties have been developed. Several techniques were used to investigate compatibility between a silicone gel and various insulation fluids. Equipment for electric endurance testing of power electronic components at dc stress under controlled temperature and humidity was developed. Performance of high voltage diodes covered with various insulation liquids, coatings and gel covering were studied.Liquid insulation of IGBT modules: Long term chemical compatibility and high voltage endurance testingacceptedVersio

Study of filamentation with a high power high repetition rate ps laser at 1.03 µm

International audienceWe study the propagation of intense, high repetition rate laser pulses of picosecond duration at 1.03 µm central wavelength through air. Evidence of filamentation is obtained from measurements of the beam profile as a function of distance, from photoemission imaging and from spatially resolved sonometric recordings. Good agreement is found with numerical simulations. Simulations reveal an important self shortening of the pulse duration, suggesting that laser pulses with few optical cycles could be obtained via double filamentation. An important lowering of the voltage required to induce guided electric discharges between charged electrodes is measured at high laser pulse repetition rate.-repetition-rate picosecond pump laser based on a Yb:YAG disk amplifier for optical parametric amplification

Stabilizing Soybean Production in Northeast Texas with Early Planting of Early-Maturing Soybean Varieties.

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Practice makes the model: a critical review of stormwater green infrastructure modelling practice

Green infrastructures (GIs) have in recent decades emerged as sustainable technologies for urban stormwater management, and numerous studies have been conducted to develop and improve hydrological models for GIs. This review aims to assess current practice in GI hydrological modelling, encompassing the selection of model structure, equations, model parametrization and testing, uncertainty analysis, sensitivity analysis, the selection of objective functions for model calibration, and the interpretation of modelling results. During a quantitative and qualitative analysis, based on a paper analysis methodology applied across a sample of 270 published studies, we found that the authors of GI modelling studies generally fail to justify their modelling choices and their alignments between modelling objectives and methods. Some practices, such as uncertainty analysis, were also found to be limited, despite their necessity being widely acknowledged by the scientific community and their application in other fields. In order to improve current GI modelling practice, the authors suggest the following: i) a framework, called STAMP, designed to promote the standardisation of the documentation of GI modelling studies, and ii) improvements in modelling tools for facilitating good practices, iii) the sharing of data for better model testing, iv) the evaluation of the suitability of hydrological equations for GI application, v) the publication of clear statements regarding model limitations and negative results.publishedVersio

The CHeriScape project, 2014-2016 : key messages from CHeriScape : cultural solutions for cultural problems

publishedVersio

Clinical impact and proposed application of molecular markers, genetic variants, and cytogenetic analysis in mast cell neoplasms: Status 2022

Mast cell neoplasms are an emerging challenge in the fields of internal medicine, allergy, immunology, dermatology, laboratory medicine, and pathology. In this review, we discuss the current standards for the diagnosis and prognostication of mast cell neoplasms with special reference to clinically relevant germline and somatic gene variants. In patients with cutaneous mastocytosis or with indolent systemic mastocytosis (SM), various KIT-activating mutations act as key molecular drivers of the disease. In adults, KIT p.D816V is by far the most prevalent driver, whereas other KIT mutants are detected in nearly 40% of children. In advanced SM, including aggressive SM, SM with an associated hematological neoplasm, and mast cell leukemia, additional somatic mutations in other genes, such as SRSF2, JAK2, RUNX1, ASXL1, or RAS, may be detected. These drivers are more frequently detected in SM with an associated hematological neoplasm, particularly in male patients. Recently, hereditary alpha-tryptasemia has been identified as a genetic trait more prevalent in SM compared with healthy controls. Moreover, hereditary alpha-tryptasemia is more frequent in patients with SM with Hymenoptera venom allergy and severe mediator-related symptoms than in patients with SM without symptoms. On the basis of this knowledge, we propose a diagnostic algorithm in which genetic markers are applied together with clinical and histopathologic criteria to establish the diagnosis and prognosis in SM

Definitions, Criteria and Global Classification of Mast Cell Disorders with Special Reference to Mast Cell Activation Syndromes: A Consensus Proposal

Activation of tissue mast cells (MCs) and their abnormal growth and accumulation in various organs are typically found in primary MC disorders also referred to as mastocytosis. However, increasing numbers of patients are now being informed that their clinical findings are due to MC activation (MCA) that is neither associated with mastocytosis nor with a defined allergic or inflammatory reaction. In other patients with MCA, MCs appear to be clonal cells, but criteria for diagnosing mastocytosis are not met. A working conference was organized in 2010 with the aim to define criteria for diagnosing MCA and related disorders, and to propose a global unifying classification of all MC disorders and pathologic MC reactions. This classification includes three types of `MCA syndromes' (MCASs), namely primary MCAS, secondary MCAS and idiopathic MCAS. MCA is now defined by robust and generally applicable criteria, including (1) typical clinical symptoms, (2) a substantial transient increase in serum total tryptase level or an increase in other MC-derived mediators, such as histamine or prostaglandin D 2, or their urinary metabolites, and (3) a response of clinical symptoms to agents that attenuate the production or activities of MC mediators. These criteria should assist in the identification and diagnosis of patients with MCAS, and in avoiding misdiagnoses or overinterpretation of clinical symptoms in daily practice. Moreover, the MCAS concept should stimulate research in order to identify and exploit new molecular mechanisms and therapeutic targets. Copyright (C) 2011 S. Karger AG, Base