Influence of Cooling Scenarios on the Evolution of Microstructures in Nickel-Based Single Crystal Superalloys

The reprecipitation and evolution of γ’ precipitates during various cooling approaches from supersolvus temperature are studied experimentally and via phase field simulation in nickel-based single crystal superalloys. The focus of this paper is to explore the influence of cooling methods on the evolution of the morphology and the distribution of γ’ precipitates. It is demonstrated that small and uniform spherical shape γ’ particles formed with air cooling method. When the average cooling rate decreases, the particle number decreases while the average matrix and precipitate channel widths increase. The shape of γ’ precipitates which changed from spherical to cubic and irregular characteristics due to the elastic interaction and elements diffusion are observed with the decrease of the average cooling rate. The phase field simulation results are in good agreement with the experimental results in this paper. The research is a benefit for the study of the rejuvenation heat treatment in re-service nickel-based superalloys.

Development and Application of Internal Circulating Water-cooled Electromagnetic Separator

For dusty and explosive use environment, especially in coal mines, mostly self-cooled and water-cooled electromagnetic iron separators are used. This article introduces the application of water cooling internal circulation technology to electromagnetic separator equipment for the first time, the advantages and disadvantages of the three cooling methods as well as the development process and application prospects of the internal circulating water-cooled electromagnetic separator are introduced and analyzed respectively.

Modelling and optimization of magnesium alloy milling parameters

In the pursuit to lighter, less consuming products, manufacturers, especially in aviation and automotive industries, are turning more and more to using lightweight alloys such as the ones based on magnesium. Higher requirements for increased productivity have led to concepts like high-speed machining (HSM), high feed machining (HFM) or high-efficiency machining. Tighter regulations concerning requiring for more environmentally friendly industrial processes led to limitations in the use of cooling liquids and a search for cooling methods with less impact (dry cutting, cryogenic cooling, near dry machining and others). Better machining processes can only be achieved by modelling and optimization. This paper briefly presents the results obtained by our research team concerning the modelling and optimization attempts on face milling of magnesium alloys using different methods: design of experiments (e.g. factorial design, response surface method), fuzzy logic or neural networks.

Lithium-Ion Battery Thermal Management Systems: A Survey and New CFD Results

The environment has gained significant importance in recent years, and companies involved in several technology fields are moving in the direction of eco-friendly solutions. One of the most discussed topics in the automotive field is lithium-ion battery packs for electric vehicles and their battery thermal management systems (BTMSs). This work aims to show the most used lithium-ion battery pack cooling methods and technologies with best working temperature ranges together with the best performances. Different cooling methods are presented and discussed, with a focus on the comparison between air-cooling systems and liquid-cooling systems. In this context, a BTMS for cylindrical cells is presented, where the cells are arranged in staggered lines embedded in a solid structure and cooled through forced convection within channels. The thermal behavior of this BTMS is simulated by employing a computational fluid dynamics (CFD) approach. The effect of the geometry of the BTMS on the cell temperature distribution is obtained. It is shown that the use of materials with additives for the solid structure enhances the performance of the system, giving lower temperatures to the cells. The system is tested with air-cooling and water-cooling, showing that the best performances are obtained with water-cooling in terms of cell packing density and lowest cell temperatures.

Review of air-cooling strategies, combinations and thermal analysis (experimental and analytical) of a permanent magnet synchronous motor

This paper gives a brief review of advanced cooling methods and applications to the permanent magnet synchronous motors (PMSMs), as well as investigates the cooling systems design problem for PMSM systems. Heat sources and losses together with analytical and practical analyses are described. Next, the temperature distribution and its influence on the PMSM is investigated using simulation results. The main part of the paper includes a review of the proposed cooling methods that will release the requirement of heat transfer of the PMSM. The finite element methods (FEM) are applied using the AnSys CFD software to obtain high accuracy thermal model of the PMSM system. The new developed forced air-cooling methods are given in details, which enable to effectively redistribute the temperature and heat transfer increasing the efficiency of the PMSM machine. Examples of CFD simulation are outlined to illustrate the effectiveness and benefits of the strategies developed.

Computational Modeling of Passive and Active Cooling Methods to Improve PV Panels Efficiency

This paper presents the computational modeling of three cooling systems based on three different methods (passive, active, and hybrid), to improve the efficiency of PV panels when operating beyond the recommended temperature under standard test conditions. All simulations were implemented using the COMSOL Multiphysics software. In the passive method, through-holes were made in the solar panel, to allow the transfer of heat by convection due to the air flow. In the active method, water was used to cool the solar panel, spraying it on the front when the operating temperature reaches a threshold value. The analysis includes both fluid dynamics and heat transfer effects. In addition, a hybrid method that uses both passive and active cooling methods simultaneously was implemented. Finally, a mathematical model for the PV panel is presented, which allowed obtaining the changes in the output power from the reduction in the operating temperature. Results demonstrated improvements in the performance of the solar panel with the implementation of the three cooling systems, showing better performance in the active and hybrid methods compared to the passive method.

Impact of cooling method on the outcome of initial shockable or non-shockable out of hospital cardiac arrest patients receiving target temperature management: a nationwide multicentre cohort study

Background Little is known about the effectiveness of surface cooling (SC) and endovascular cooling (EC) on the outcome of out-of-hospital cardiac arrest (OHCA) patients receiving target temperature management (TTM) according to their initial rhythm. Methods We retrospectively analysed data from the Japanese Association for Acute Medicine Out‐of‐Hospital Cardiac Arrest registry, a multicentre, prospective nationwide database in Japan. For our analysis, OHCA patients aged ≥ 18 years who were treated with TTM between June 2014 and December 2017 were included. The primary outcome was 30-day survival with favourable neurological outcome defined as a Glasgow–Pittsburgh cerebral performance category score of 1 or 2. Cooling methods were divided into the following groups: SC (ice packs, fans, air blankets, and surface gel pads) and EC (endovascular catheters and any dialysis technique). We investigated the efficacy of the two categories of cooling methods in two different patient groups divided according to their initially documented rhythm at the scene (shockable or non-shockable) using multivariable logistic regression analysis and propensity score analysis with inverse probability weighting (IPW). Results In the final analysis, 1082 patients were included. Of these, 513 (47.4%) had an initial shockable rhythm and 569 (52.6%) had an initial non-shockable rhythm. The proportion of patients with favourable neurological outcomes in SC and EC was 59.9% vs. 58.3% (264/441 vs. 42/72), and 11.8% (58/490) vs. 21.5% (17/79) in the initial shockable patients and the initial non-shockable patients, respectively. In the multivariable logistic regression analysis, differences between the two cooling methods were not observed among the initial shockable patients (adjusted odd ratio [AOR] 1.51, 95% CI 0.76–3.03), while EC was associated with better neurological outcome among the initial non-shockable patients (AOR 2.21, 95% CI 1.19–4.11). This association was constant in propensity score analysis with IPW (OR 1.40, 95% CI 0.83–2.36; OR 1.87, 95% CI 1.01–3.47 among the initial shockable and non-shockable patients, respectively). Conclusion We suggested that the use of EC was associated with better neurological outcomes in OHCA patients with initial non-shockable rhythm, but not in those with initial shockable rhythm. A TTM implementation strategy based on initial rhythm may be important.

Dynamic Infrared Thermography (DIRT) in Biomedical Applications: DIEP Flap Breast Reconstruction and Skin Cancer

Infrared thermography technology has improved drastically in recent years and is regaining interest in medicine for applications such as deep inferior epigastric perforate flap breast reconstruction, breast cancer diagnosis, skin tissue identification, psoriasis detection, etc. However, there is still a need for an optimised measurement setup and protocol in order to capture the most suitable images for decision making and further processing. Nowadays, different cooling methods are being used; nevertheless, a general optimised cooling protocol is not yet defined. In this manuscript, several cooling techniques, as well as the measurement setups, are reviewed and optimised. It is possible to enhance the thermal images by selecting an appropriate cooling method and duration, and additionally, an optimised measurement setup enables a comparison between different inspections.