A comparison of bioclimatic conditions on Franz Josef Land (the Arctic) between the turn of the nineteenth to twentieth century and present day

The paper presents the variability of meteorological conditions: air temperature, wind speed and relative air humidity; and biometeorological indices: wind chill temperature, predicted clothing insulation and accepted level of physical activity on Franz Josef Land (in Teplitz Bay and Calm Bay) in the years 1899–1931. It employs meteorological measurements taken during four scientific expeditions to the study area. The analysis mainly covered the period October–April, for which the most complete data set is available. For that period of the year, which includes the part of the year with the Franz Josef Land’s coldest air temperatures, the range and nature of changes in meteorological and biometeorological conditions between historical periods and the modern period (1981–2010) were studied. The data analysis revealed that during the three oldest expeditions (which took place in the years 1899–1914), the biometeorological conditions in the study area were more harsh to humans than in the modern period (1981–2010) or similarly harsh. In contrast, during the 1930/1931 expedition, which represents the Early Twentieth CenturyWarming (ETCW), conditions were clearly more favourable (including predicted clothing insulation being 0.3 clo lower and 4.0 °C higher wind chill temperature than conditions observed nowadays)

Assessing heat-related health risk in Europe via the Universal Thermal Climate Index (UTCI)

In this work the potential of the Universal Thermal Climate Index (UTCI) as a heat-related health risk indicator in Europe is demonstrated. The UTCI is a bioclimate index that uses a multi-node human heat balance model to represent the heat stress induced by meteorological conditions to the human body. Using 38 years of meteorological reanalysis data, UTCI maps were computed to assess the thermal bioclimate of Europe for the summer season. Patterns of heat stress conditions and non-thermal stress regions are identified across Europe. An increase in heat stress up to 1°C is observed during recent decades. Correlation with mortality data from 17 European countries revealed that the relationship between the UTCI and death counts depends on the bioclimate of the country, and death counts increase in conditions of moderate and strong stress, i.e. when UTCI is above 26°C and 32°C. The UTCI’s ability to represent mortality patterns is demonstrated for the 2003 European heatwave. These findings confirm the importance of UTCI as a bioclimatic index that is able to both capture the thermal bioclimatic variability of Europe, and relate such variability with the effects it has on human health

Global forecasting of thermal health hazards: the skill of probabilistic predictions of the Universal Thermal Climate Index (UTCI)

Although over a hundred thermal indices can be used for assessing thermal health hazards, many ignore the human heat budget, physiology and clothing. The Universal Thermal Climate Index (UTCI) addresses these shortcomings by using an advanced thermo-physiological model. This paper assesses the potential of using the UTCI for forecasting thermal health hazards. Traditionally, such hazard forecasting has had two further limitations: it has been narrowly focused on a particular region or nation and has relied on the use of single ‘deterministic’ forecasts. Here, the UTCI is computed on a global scale,which is essential for international health-hazard warnings and disaster preparedness, and it is provided as a probabilistic forecast. It is shown that probabilistic UTCI forecasts are superior in skill to deterministic forecasts and that despite global variations, the UTCI forecast is skilful for lead times up to 10 days. The paper also demonstrates the utility of probabilistic UTCI forecasts on the example of the 2010 heat wave in Russia

Badania rozkładu pola magnetycznego na powierzchni styków AMF

Rozkład osiowego pola magnetycznego na powierzchni styków komór próżniowych odgrywa decydującą rolę w ograniczaniu erozji styków podczas wyłączania prądu zwarciowego. Ograniczenie erozji styków możliwe jest przez równomierny rozkład osiowego pola magnetycznego na całej powierzchni styku. Z tego względu, w projektowaniu styków, należy stosować metody obliczeniowe do sprawdzenia składowej osiowej rozkładu pola magnetycznego. W artykule podano wynik analizy rozkładu składowej osiowej pola magnetycznego dla styku bipolarnego z nacięciami ukośnymi i z nacięciami o kształcie łuku. Do analizy stosowano program komputerowy FLUX 3D. Wykonano również badania rozkładu strumienia łuku dyfuzyjnego w rozbieralnej komorze próżniowej podczas wyłączania prądu zwarciowego o wartości 15 kA.The axial magnetic field (AMF) distribution on the contact surface plays an important role in short circuit current interruption. To minimize erosion of the contact the AMF should be uniformly distributed over the contact plates. During theoretical analysis of bipolar contacts, the design of the contact coil and the slots made in the contact’s plate, as well as the orientation of the steady contact relative to the moving contact were taken into account. The FLUX 3-D computer program was used for the calculation of the AMF and the results were compared and analyzed. To investigate the distribution of arc spots on the contact plate surface experiments were conducted in a dismountable vacuum chamber during a 15 kA short circuit current interruption

Simulations of the human heat balance during Mount Everest summit attempts in spring and winter

The majority of research dealing with the impacts of the Himalayan climate on human physiology focuses on low air temperature, high wind speed, and low air pressure and oxygen content, potentially leading to hypothermia and hypoxia. Only a few studies describe the influence of the weather conditions in the Himalayas on the body’s ability to maintain thermal balance. The aim of the present research is to trace the heat exchange between humans and their surroundings during a typical, 6-day summit attempt of Mount Everest in the spring and winter seasons. Additionally, an emergency night outdoors without tent protection is considered. Daily variation of the heat balance components were calculated by the MENEX_HA model using meteorological data collected at automatic weather stations installed during a National Geographic expedition in 2019–2020. The data represent the hourly values of the measured meteorological parameters. The research shows that in spite of extreme environmental conditions in the sub-summit zone of Mount Everest during the spring weather window, it is possible to keep heat equilibrium of the climbers’ body. This can be achieved by the use of appropriate clothing and by regulating activity level. In winter, extreme environmental conditions in the sub-summit zone make it impossible to maintain heat equilibrium and lead to hypothermia. The emergency night in the sub-peak zone leads to gradual cooling of the body which in winter can cause severe hypothermia of the climber’s body. At altitudes < 7000 m, climbers should consider using clothing that allows variation of insulation and active regulation of their fit around the body.</p

Investigation of HID-lamp light emission differences for different power supply methods

This paper presents investigation of methods for reducing light pulsation and plasma temperature inside a high intensity discharge (HID) lamp arc tube. Differences found in light emission of an arc tube plasma channel under different power supply methods are presented and discussed in this work. The novelty of the paper lies in systematical investigation of different power converter supply methods and demonstrating that it has a significant influence on plasma temperature in an arc tube. The tested lamp was powered by electronic ballasts controlled by different algorithms, which forced their current waveform. To compare the results, the authors performed measurements on a discharge lamp powered by a standard electromagnetic ballast. The investigation of plasma parameters is based on the optical spectroscopy method. It was shown that by using the appropriate current shape of a high switching frequency supply converter, the plasma temperature of an HID lamp can be reduced almost by half

Projektowanie komór próżniowych do wyłączników wysokiego napięcia

W artykule przedstawiono opis modelu komory próżniowej przeznaczonej do wyłącznika wysokiego napięcia. Model został przeanalizowany i częściowo zbadany w celu zapewnienia odpowiedniej wytrzymałości elektrycznej i mechanicznej. Wstępnie rozważono: wytrzymałość termiczną w warunkach obciążeniowych i zwarciowych, wytrzymałość na narażenia elektryczne, przeanalizowano rozkład pola magnetycznego na powierzchni styków jak i w przestrzeni pomiędzy stykami, wyznaczono rozkład pola elektrycznego wewnątrz komory próżniowej. Styki bipolarne zbadano w rozbieralnej komorze próżniowej. Celem tych obliczeń i badań było opracowanie odpowiedniej geometrii i rozważenie możliwości techno-logicznych wykonania modelu komory do wyłącznika wysokiego napięcia.The paper presents a vacuum chamber model for a HV circuit breaker. Manufacturers of vacuum circuit breakers apply the axial magnetic field (AMF) to stabilise the electric arc diffusion during current breaking process. The model was analyzed and partly tested to assure its mechanical and electrical withstand. The results of the preliminary calculations of thermal behavior of the vacuum chamber in short-circuit conditions, the magnetic field distribution between contact plates as well as in the contact gap and the dielectric stress inside of the vacuum chamber are shown. The bipolar contacts were tested in a dismountable vacuum chamber. The aim was to determine geometry and to recognize technology and manufacturing facilities required