Search

• The purpose of prebaking of the vessel is to check the quality of the numerous welds. • The maximal baking power was 65 kW. • The maximal temperature of vacuum shell was 187 °C. • The difference between maximal and minimal temperatures of vessel shell was 60 °C. • After the end of baking, no leaks were found in shell welds. Presently, the Tokamak T-15MD is being built in the NRC "Kurchatov Institute". The vacuum vessel was manufactured and passed the preliminary vacuum tests at the plant in St. Petersburg (Efremov Institute) in 2016. Vacuum vessel consists of toroidal shell made from 321stainless steel of 5 mm and 8 mm thickness, horizontal and vertical ports (152 in total), in-vessel elements. The vessel volume is 47 m3 and the surface square faced to plasma is ˜200 m2. The purpose of prebaking of the vacuum vessel is to check the quality of the numerous welds. To bake the vacuum vessel up to 220 °C at the plant in Bryansk, the Ohmic heaters have been laid on vessel shell surface both outside and inside. The thermal insulation (basalt wool) was applied on the outer surface of the vessel. The vessel's surface temperature was controlled by thermocouples. The currents in heaters was regulated by four thyristor regulators. The temperature data were processed and stored using the data acquisition system. [ABSTRACT FROM AUTHOR]

A detailed study of carbon dioxide (CO2) sources from petroleum refineries in Kuwait was conducted. The aim was to estimate the amount of CO2 being emitted and determine the influencing factors on physical and chemical process in refineries. Three refineries were considered in this work, processing around 900 Mbpd of crude oil. Process heaters stacks constituted 62-75% of the CO2 emissions, ranking at the top of the sources. Hydrogen production (HP) units via steam-methane reforming ranked seconded in the final assessment, ranging from 12% to 25% in the studied refineries. The configuration of the refinery was determined to be a critical factor in such work. The properties of the processed oil, in terms of density, sulfur content and API were essential in comparing results obtained in this work to other refineries specific rates. Carbon capture and storage (CCS) presents itself as a viable solution for the reduction of the carbon footprint of Kuwait downstream sector, especially when considering the purity of the HP units product gas. The work presented in this paper can be considered as the cornerstone of future carbon mitigation plans in the country. [ABSTRACT FROM AUTHOR]

There has been expeditious growth and advancement in the development of portable, automated, integrated, and miniaturized temperature management systems. Temperature management system plays a vital role in microfluidic technology, an emerging area that couples multidisciplinary fields and manipulates small amounts of fluids (10−9–10−18 L). A microthermofluidic (MTF) system is designed by combining microfluidics and a thermal management system. The MTF approach harnesses the fluid mechanism to coordinate, manipulate, and merge the reaction sample and provide an effective and efficient desired temperature that plays significant progress in several biochemical, biomedical, and biological applications. This system can accomplish numerous purposes by either varying the reaction conditions within a microchannel or performing reactions in series, parallel, or combinations. Further, these reactions usually require a precise, consistent, and stable temperature, which can be achieved using contact or non-contact heating methods such as electrical, optical, acoustic, and mechanical heating. This work describes thermal energy sources in microfluidic devices and highlights advancements in microthermofluidic devices used for nanoparticle synthesis, biochemical, biomedical, and engineering applications. This work comprehends the general review on recent advances combining microfluidics and thermal management systems. Finally, challenges involved in the extensive use of MTF devices are discussed, and further deliberations for future research in this area are highlighted. The wide range of applications necessitates rapid thermal regulation with significant progressive hints for the biomedical, biotechnological, and chemical sub-areas, relying on the appropriate heating method. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: In conjunction with John Zink Co., LLC, the Chevron Energy Technology Company conducted a three part study evaluating potential issues with switching refinery process heaters from fuel gas to hydrogen fuel for the purpose of greenhouse gas emissions reduction via CO2 capture and storage. The focus was on the following areas: • Heater performance • Burner performance and robustness • Fuel gas system retrofit requirements This paper will summarize the findings of the study. [Copyright &y& Elsevier]

Abstract: This paper discusses the results of an experimental and numerical study of fluid flow and heat transfer in an enclosure where multiple heaters are arranged in a staggered fashion. Experiments were carried out for Reynolds numbers, in the range 1800 ≤ Re ≤ 4500 and Grashof numbers in the range 2.5 × 104 ≤ Gr ≤ 3 × 105. Numerical simulations were carried out for two dimensional, steady, incompressible turbulent flow and the results of the numerical study are compared with the experimental results. The temperature distribution gives an insight into the power management among the heaters, so that the “coolest” heater can be loaded most to maximize the total heat dissipation, for a prescribed temperature excess, for all the heaters. Two methods are used to achieve the target temperature for all heaters, namely (i) trial and error method and (ii) the response surface method. The latter method was adopted, to simultaneously maximize the heat input and minimize the temperature deviation from the target temperature, by employing a composite objective function. The numerically obtained optimal solution was finally verified by carrying out experiments. The method of response surface was found to be effective in optimizing the total heat transfer for a given target temperature. [Copyright &y& Elsevier]

Abstract: In Serbia, around 50% of energy is used in built environment and most of it for 6-month heating in residential buildings. Because of actual international efforts to protect environment, energy conservation in heating in residential buildings is an issue of permanent research interest. In this paper, we tried to determine how type of partitions inside a residential building influences energy consumption and demand for houses in cold climate and consequently energy conservation. For a typical house in Serbia, by using software HTB2, it was evaluated how its heating depends on six applied types of partitions. It was found that (1) the house with glass-wool partitions would have the minimum yearly heat consumption, (2) the house with masonry partitions would require heaters of minimum size, (3) the house with siporex partitions would require the lowest investment in partitions and heaters, and (4) the house with glass-wool partitions would yield the highest net savings during the life cycle of the house. [Copyright &y& Elsevier]

Abstract: Energy is the prime source of human activities in all sectors of life. Traditionally fossil fuel has been the prime source of energy. However, there are two major concerns regarding fossil fuels, i.e. their rapid depletion and their contribution towards growing global warming. It is being widely realized that for sustainable development presently used energy mediums such as fossil fuel and nuclear power have to be quickly replaced by renewable energy sources. The latter are sustainable and have the potential to meet present and future projected global energy demands without inflicting any environmental impacts. Pakistan is amongst the most prominent cotton producing countries in the world. The affluent availability of local cotton has lead to a well-established textile sector in Pakistan. A large proportion of its cotton products go into export. Being a successful candidate in international textile market Pakistani textile industry is continuously seeking modern and high-tech facilities to improve quality of its products. The biggest challenge Pakistani textile industry is facing today is how to cut down its environmental burdens to cope with the international standards on the issue. Water heating system as required for dying process is one of the major energy consuming areas in fossil fuel-run Pakistani textile industry. Water heating system therefore has a significant contribution towards total environmental impacts associated with textile sector. This work presents an alternate, sustainable solution for water heating by means of fossil fuel. It has been shown herein that under Pakistan''s climate solar energy can contribute significantly towards this duty. In the present work two different designs of built-in storage water heater—plain and newly designed finned type—were constructed to compare their thermal performance. Three months of experimental data were collected for the two heaters. The solar fractions for this period were found to be 63 and 73%, respectively. The monetary and embodied energy payback periods for the two heaters were, respectively, found to be 6.7 and 6.1 years, and 185 and 169 days. [Copyright &y& Elsevier]

Abstract: Silicon-on-diamond (SOD) technology is proposed as an advanced alternative to conventional silicon-on-insulator (SOI) technology. In SOD, the electrical insulator is diamond, the best thermal conductor in nature. In our SOD concept, the diamond film is highly oriented (HOD), 75–100 μm thick and serves as an electrical insulator, heat spreader and substrate. In this paper, we focus on the thermal evaluation of SOD with a Si device layer on the nucleation side of the diamond film. The obtained results indicated that SOD can sustain up to 10-times higher power loads than SOI. The results were experimentally obtained by R(T) measurements of micro-heaters deposited on the Si device layer and by thermal imaging. 3D finite element thermal simulations using ANSYS confirmed that these numbers are in good agreement with expectations. [Copyright &y& Elsevier]

An introduction to the various types of calorimeters is given. The requirements for precise temperature measurements with thermistors are derived. Methods and equations for accurate heat exchange corrections for isoperibol temperature-change calorimetry under various conditions are derived. The characteristics and design principles for constant temperature baths are discussed. The construction of devices for addition of reagents, of stirrers, and of calibration heaters is described. [Copyright &y& Elsevier]

Droplet microfluidic platforms have been developed to produce mono-dispersed microdroplets and provided substanial progress in many chemical, biological, and biomedical applications. Droplets generated in microfluidics can perform multiple functions by either changing the reaction conditions within each droplet or doing the same reactions in parallel, series, or combinations. These reactions mostly require precise control of droplet temperature using contact or non-contact heating sources, including optical-, electrical-, mechanical- and acoustic-based heating techniques. This work exclusively presents thermal energy sources in microfluidics and provides insights into the physical interpretation of thermal actuation of microdroplets. It then highlights advances in thermal droplet microfluidics for biomedical, chemical and engineering applications. The biomedical applications include biosensing, drug discovery, drug testing, and antibiotic susceptibility testing. The chemical applications include synthesis of microgel droplets and Janus particles. The engineering applications include an overview of thermal manipulation of the generated droplets and employing emulsified droplets in thermal management and cooling applications. This review supports the development of new methods to meet different demands arising from these applications. Finally, the challenges involved in the widespread use of thermal microdevices are discussed and further considerations for prospective research in this area are highlighted. • Mechanical heating as a direct contact heating method and optothermal and acoustothermal as contact-free techniques are comprehensively discussed for droplet microfluidic. • On-chip droplet-based PCR in clinical diagnosis and microparticle synthesis for chemical applications are explained as two crucial applications of thermal droplet-based microfluidic systems. • The main challenges that hinder the wide-spread of thermal droplet-based microfluidic systems are explained such as two factors, heat supply and the chip materials. • Off-chip heating source and control, along with significant challenges in heat supply, are highlighted. • Heat accumulation and poor thermal characteristics of PDMS as the main challenges of PDMS -based microfluidic device material are pointed out. [ABSTRACT FROM AUTHOR]