Influence of washing on textile material thermal properties under exposure of an open flame and heating ele-ment heat flow

Elevated temperatures are factors causing harm to human health and life. To ensure protection, various personal protective equipment is used, which includes special protective clothing. The article discusses the heat-shielding indicators of the safety of textile material. In order to determine the heat-shielding properties of the material, various types of exposure are used – convective heat from a heating element and an open flame. Fabrics of various raw materials and surface density are used for sewing special protective clothing. Five clothes were selected for the research. The research was held under the exposure of an open flame and convective heat of heating element with a comparable heat flux density equal to 80 kW/m². Also, research was held under influence of multiple wash cycles on radiant heat transfer index and heat transfer index.

Inline Setup Provides Automatic Measurement of PVT Behavior of Drilling Fluids

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 204084, “Automatic Measurement of the Dependence on Pressure and Temperature of the Mass Density of Drilling Fluids,” by Eric Cayeux, SPE, NORCE, prepared for the 2021 SPE/IADC International Drilling Conference and Exhibition, originally scheduled to be held in Stavanger, 9–11 March. The paper has not been peer reviewed. The mass density of drilling fluids usually is measured manually with a mud balance. The pressure and temperature dependence of the mass density of the fluid [i.e. its pressure/volume/temperature (PVT) behavior] then is estimated. Variations in the composition of the fluid mix and uncertainties regarding the PVT behavior of each component, however, may lead to inaccuracies. An apparatus that measures the PVT behavior of the drilling fluid contained in a pit directly and automatically has been designed. Inline PVT Measurement The pressure and temperature dependence of drilling fluids can be described by a biquadratic function. However, API Recommended Practice 13D recommends using a linear function of temperature combined with a quadratic form of pressure. Because this process involves six parameters, at least six measurements must be made under different conditions of pressure and temperature. A starting point is to measure the mass density of the fluid under six different pairs of pressures and temperatures. To keep the design of the apparatus as simple as possible, it ideally would not operate under high-pressure and -temperature conditions. Therefore, knowing the range of pressures and temperatures sufficient for taking sample measurements is useful in order to be able to extrapolate the model at higher pressure and temperature conditions with acceptable accuracy. The densitometer’s measurement precision of 0.05 kg/m3 and repeatability of 0.01 kg/m3 is known, so stochastic simulations of the possible measurement error for various spans of investigated pressures and temperatures can be performed. In this study, the authors con-sider that the calibrated PVT model shall be used for a range of pressure of 1000 bar and a range of temperature of 200°C. It is possible to calculate the root mean square of the proportion error between the predicted density value and the “true” value when varying stochastically the systematic bias on the density measurement when the calibration samples are spanning small ranges of pressure and temperature. A possible design for an inline apparatus could be to pump the drilling fluid past a controllable heating element and having a controllable choke downstream of the densitometer apply a pressure while measuring the mass density. The setpoints for the heating element and the choke would be changed six times in order to collect the necessary mass densities to calibrate the PVT model. Changing the temperature of the heating element, however, can require several minutes, and gathering a complete set of calibration measurements may easily take 15 to 30 minutes. An alternative could be to perform six measurements simultaneously. The densitometers can be mounted in series. The configuration could be with six parallel branches or any combinations between series and parallel branches. With two parallel branches, in one branch the temperature of the fluid is not modified, while it is modified in the second branch. For each of the two branches, back pressure is applied at two intermediate positions. This configuration has the advantage of using fewer chokes and pressure sensors (four instead of five).

Fabrication of Planar Heating Chuck Using Nichrome Thin Film as Heating Element for PECVD Equipment

Improving semiconductor equipment and components is an important goal of semiconductor manufacture. Especially during the deposition process, the temperature of the wafer must be precisely controlled to form a uniform thin film. In the conventional plasma-enhanced chemical vapor deposition (PECVD) chuck, heating rate, and temperature uniformity are limited by the spiral pattern and volume of the heating element. To overcome the structural limitation of the heating element of conventional chuck, we tried to develop the planar heating chuck (PHC), a 6-inch PECVD chuck with a planar heating element based on NiCr thin film that would be a good candidate for rapidly and uniformly heating. The time for the temperature elevation from room temperature to 330 °C was 398 s. In a performance evaluation, the fabricated PHC successfully completed a SiO2 PECVD process.

ANALYSIS OF THE INFLUENCE OF DISTANCE BETWEEN THE HEATING ELEMENT AND THE SAMPLE ON THE SMOKE FORMING ABILITY OF PINE WOOD IN VIETNAM

Series of fire tests was carried out to determine the smoke-forming ability of conifer- ous wood at different distances of the sample from the heating element. It was found that the same heat flux density leads to a difference in temperature at different distances, which significantly affects the test result.

Performance analysis on series and parallel circuit configurations of a four-cell thermoelectric generator module design

This study presents a technique in recovering energy from low-grade waste heat of a Proton Exchange Membrane Fuel Cell (PEMFC). The goal is to study the functionality and performance using a multiple cell thermoelectric generator (TEG) module. The test bench consists of a heating element, a test section, and a cooling section. The heating element supplies a hot stream temperature of 53°C and 58°C that represents the waste heat from an actual PEMFC stack. The module comprises four TEG cells with heat pipes coupled with a heat sink system. The main variables were the TEG cooling modes of natural convection (0 m/s) and forced convection (at 5 m/s and 10 m/s) and the series and parallel circuit configurations of the module. At 58°C waste heat temperature, forced convection cooling at 10 m/s gave the highest voltage and power output of 140 mV and 1960 µW. The outputs of the series circuit was 159% higher than the parallel circuit. This initial simple TEG module design has shown that it has a good prospect to compensate for the ultra-low waste heat temperature of a PEMFC. Future designs of the modules need to identify a more optimized approach to improve the outputs and contribute to the long-term sustainability of PEMFC systems.

Development of low-pressure electric steam heater

The study was devoted to solving the issue of creating new electric heating devices that can be used in autonomous heat supply systems. The issues were resolved by developing an original low-pressure electric steam heater. The study was aimed at improving the efficiency of heat supply systems for buildings and structures. Given the current trends in the global striving for energy conservation, it cannot be fully realized without the introduction of high-tech and low-energy-consuming electrical equipment. As a result of theoretical studies of a heat pipe with an electric heater, a design of an electrovacuum heating element has been developed. The low-pressure electric steam heater can be used in heat supply systems of autonomous users. Thermal energy transfer is currently accompanied by substantial energy losses since the heat carrier has to pass considerable distances. Switching of the facility to the heating plant is impossible in some cases because of technical problems or significant material costs for laying pipelines. As a result of the study, the dependence of heating the heat pipe at various volumes of the heat carrier and mass of the pipe itself was established. When a certain mass is reached, the temperature of the heating surfaces can reach 70 °C which is considered acceptable. The experimental data obtained have made it possible to develop an electric heater of new generation with a fundamentally new design of the heating element. It combines the efficiency of an electric spiral and comfortable warmth from a traditional radiator. This heater is an explosion and fire-safe and can be integrated into the Smart Home system

Improvement of Temperature Precision in Embryo-Incubator Chamber by Reducing Fluctuations

Temperature is one of the parameters that affects development of embryos. Therefore, it is important to keep stability of temperature in the chambers of embryo-incubators. In modern incubators, some accuracy of temperature has been achieved, although fluctuations are not eliminated yet. The aim of this research was to improve temperature accuracy by reducing of fluctuations. In modern benchtop incubators, a heating element is switched on and automatically shuts off when the desired value is reached. The heating element continues to heat up to a certain temperature after switching off, and the reverse process takes place during cooling. Inappropriate temperature may adversely affect the embryo. To control temperature more precisely, a new principle with infrared sensor has been developed, where power to heater is supplied with different PWM duty cycles. As the results, much more stable temperature with less fluctuations were achieved in comparison to modern systems using thermocouples and thermistors.