Targeted Temperature Control Research Articles

Feasibility Study of Temperature Control Measures during the Construction of Large-Volume Concrete Gravity Dams in Cold Regions: A Case Study

Effective temperature control measures are crucial for achieving temperature regulation and preventing cracking in the dam body during the construction of large-volume concrete gravity dams. Due to the low ambient temperatures in winter, it is especially important to focus on temperature control measures for concrete dam construction in cold regions. This paper employs a numerical simulation method that takes into account dam temperature control measures to simulate and predict the overall temperature and stress fields of the Guanmenzuizi Reservoir Dam, and validates these simulations with field monitoring results. This study finds that the ambient temperature significantly impacts the temperature and stress of the dam body’s concrete. The internal temperature of the dam reaches its highest value approximately 7 days after pouring, followed by periodic fluctuations, with the dam body’s temperature changes exhibiting a certain lag compared to the ambient temperature. The interior of the dam is under compression, while the upstream and downstream surfaces experience significant tensile stress. This project adopts targeted temperature control measures for the cold environmental conditions of the region, which are reasonably implemented and effectively reduce the temperature rise of the concrete during construction, achieving the temperature control objectives. This study also explores the impact of the cooling water pipe density on the dam body. The research results offer valuable references for the implementation of temperature control measures and the establishment of temperature control standards for concrete gravity dams in cold regions.

Dung Beetle Optimized Fuzzy PID Algorithm Applied in Four-Bar Target Temperature Control System

With the widespread application of infrared thermal imagers in various fields, the demand for thermal imagers and their performance parameter testing equipment has increased significantly. There are particularly high demands on the detection accuracy of minimum resolvable temperature difference (MRTD) testers. Traditional MRTD testers have an issue with the four-bar target temperatures being easily affected by the external environment, resulting in non-uniform temperatures and imprecise detection results. This paper proposes an improvement to the four-bar targets by making them temperature-controllable. Temperature is controlled by installing thermoelectric coolers (TECs) and thin-film platinum resistors at the center and periphery of the four-bar targets with different spatial frequencies. The dung beetle algorithm is used to optimize fuzzy PID parameters to regulate the TEC’s heating and cooling, improving the overall temperature uniformity of the four-bar targets. Temperature simulations of the four-bar targets were conducted on the COMSOL platform, with the control part simulated on the Simulink platform. The simulation results show that, compared to traditional PID, the fuzzy PID controller reduces overshoot by approximately 3.6%, although the system still exhibits mild oscillations. The fuzzy PID controller optimized by the dung beetle optimization (DBO) algorithm, in comparison to standard fuzzy PID, reduces the settling time by about 40 s and lowers overshoot by around 7%, with oscillations in the system nearly disappearing. Comparing the fuzzy PID optimized by the particle swarm optimization (PSO) algorithm with the fuzzy PID optimized by the DBO algorithm, the DBO-based controller shows shorter rise and settling times, further illustrating the superiority of the fuzzy PID control optimized by the dung beetle algorithm. This provides a theoretical foundation for improving the accuracy of MRTD detector measurements. Finally, experimental verification was carried out. The experimental results indicate that DBO (drosophila-based optimization) has significant advantages, and its optimized results are closer to the actual values.

Cardiogenic Shock Intravascular Cooling Trial (CHILL-SHOCK)

Cardiogenic shock (CS) is complicated by high mortality rates. Targeted temperature control (TTC) has been proposed as an adjunct therapy in CS. This study aims to examine the safety of TTC in patients presenting with CS. In this open-label, randomized controlled pilot trial, 20 patients with hemodynamic criteria for CS were assigned to standard of care plus TTC vs standard of care alone. The primary outcome was a composite safety outcome, including well-described complications of TTC. Secondary outcomes included mortality at 90 days, invasive hemodynamic and echocardiographic parameters, electrocardiographic measurements, and inotrope dosing. There were no significant differences in the composite analysis of prespecified safety outcomes (3 events in the TTC group vs 0 events in the control group; P = 0.24). Patients randomized to TTC demonstrated a statistically significant increase in cardiac index and cardiac power index compared to the control group at 48-96 hours after randomization (3.6 [3.1, 3.9] L/min/m2 vs 2.6 [2.5, 3.15] L/min/m2; P = 0.029 and 0.61 [0.55, 0.7] W/m2 vs 0.53 [0.435, 0.565] W/m2; P = 0.029, respectively). TTC may be a safe adjunct therapy for patients presenting with CS and may yield improvement in specific hemodynamic parameters.

Development and testing of a PEM fuel cell stack envisioning unmanned aerial vehicles applications

This work deals with a proton exchange membrane (PEM) fuel cell stack designed for unmanned aerial vehicles (UAVs). Its performance and the effects of operating conditions are investigated. The 3-cell stack, each with 25 cm2 active area, has an open-cathode and a dead-end anode. It is cooled by the air supply fan and humidified by short-circuits. The stack power reaches 21 W at 15 A. Its individual cell voltages are similar up to 7.5 A but deviate as the current increases. The stack temperature rises with current, reaching close to 45 °C. Fan speed regulation should mainly target temperature control, as little effect on the stack power was found. Higher short-circuit duration and frequency improves the stack performance. Increasing H2 purge duration shows no significant effect. Increasing the interval between purges above a certain value causes the stack performance to decline. Below that, changing the purge interval has no effect.

An Active Pixel-Matrix Electrocaloric Device for Targeted and Differential Thermal Management.

More than 55% of electronic failures are caused by damage from localized overheating. Up to now, there is still no efficient method for targeted temperature control against localized overheating. Although some existing thermal management devices handle this issue by full coverage cooling, it generates a lot of useless energy consumption. Here, a highly efficient pixel-matrix electrocaloric (EC) cooling device is reported, which can realize a targeted and differential thermal management. The modified poly(vinylidene fluoride-tertrifluoroethylene-chlorofluoroethylene) reaches a large adiabatic temperature change of 7.8 K and is more suitable for thermal transfer and electrostatic actuation at high frequencies. All active pixels in the EC cooling device exhibit a stable temperature span of 4.6 K and a heat flux of 62mWcm-2 , which is more than twice that of the one-layer EC device. Each refrigeration pixel can be independently controlled and effectively cooled down the localized overheating site(s) in situ. The surface temperature of the simulated central processing unit decreases by 33.2 K at 120 s after applying this EC device. Such a compact, embeddable, low cost, and active solid-state pixel-matrix cooling device has great potential for localized overheating protection in microelectronics.

Optimal sensor placement and estimator-based temperature control for a deep drawing process

Deep drawing is one of the most important forming processes for the forming of flat sheet blanks, where the formation of wrinkles and the appearance of cracks can be a problem, especially in areas of high geometric complexity. The local increase of the temperature in these critical areas can help to improve the formability of the material and thus reduce defects. The present paper aims at a targeted temperature control of the die of a deep-drawing mold. For this sensors are placed systematically to develop an estimator for the spatial–temporal temperature evolution to subsequently realize tracking control using the embedded actuation devices. A continuum representation of the temperature distribution in the die is derived and transferred to a high order finite element (FE) approximation to take the complex-shaped geometry of the tool into account. Parameter identification is performed based on measurement data to improve the accuracy of the FE approximation and model order reduction (MOR) techniques are applied to determine a sufficiently low order system representation. A mixed-integer optimization problem is formulated and solved making use of different formulations of the observability Gramian to determine the optimal sensor locations and a Kalman filter is designed as an estimator based on a reduced order model. Moreover, a linear-quadratic regulator with integral part combined with the Kalman filter is developed to react efficiently towards disturbances. Finally this theoretical framework is tested in a real experiment.

Design of a temperature-feedback controlled automated magnetic hyperthermia therapy device.

Magnetic hyperthermia therapy (MHT) is a minimally invasive adjuvant therapy capable of damaging tumors using magnetic nanoparticles exposed radiofrequency alternating magnetic fields. One of the challenges of MHT is thermal dose control and excessive heating in superficial tissues from off target eddy current heating. We report the development of a control system to maintain target temperature during MHT with an automatic safety shutoff feature in adherence to FDA Design Control Guidance. A proportional-integral-derivative (PID) control algorithm was designed and implemented in NI LabVIEW®. A standard reference material copper wire was used as the heat source to verify the controller performance in gel phantom experiments. Coupled electromagnetic thermal finite element analysis simulations were used to identify the initial controller gains. Results showed that the PID controller successfully achieved the target temperature control despite significant perturbations. Feasibility of PID control algorithm to improve efficacy and safety of MHT was demonstrated.

Targeted Temperature Manipulation and Analysis of the Influence on Mechanical Properties in Large-Scale Extrusion Additive Manufacturing

Layer times in large-scale Extrusion Additive Manufacturing (EAM) of carbon fiber-reinforced thermoplastics are often outside the recommended process window. Brief layer times of tall parts with short path lengths lead to high temperatures and thus to melting of the component. In contrast, the substrate temperature decreases too far at longer layer times to achieve sufficient fusion bonding through molecular diffusion across the interface. Heating by infrared emitters and cooling by compressed air were experimentally tested and evaluated as methods for temperature control. Assuming that bond formation is mainly temperature-controlled, mechanical properties were expected to be similar to those of non-manipulated samples at the same temperatures. Samples of short carbon fiber-filled polyamide 6 in pellet form were manufactured in three test series. Infrared heating resulted in comparable tensile properties to samples at the target temperature and in a significant increase compared to the base temperature without heating. Cooling proved to be more effective when closer to the deposition nozzle, with tensile results even exceeding the expected values at temperatures below 170 °C. Overall, the results support the potential for targeted temperature control in EAM and the hypothesis that comparable bond strength can be achieved in dependence of the final substrate temperature.

Comparative Analysis of Temperature Measurement Methods based on Degree of Agreement

Many sports have a high risk of climatic ailments, such as hypothermia, hyperthermia, and heatstroke. The measurement of a sportsperson's body core temperature (Tc) may have an impact on their performances and it assists them to avoid injuries as well. To avoid complications like electrolyte imbalances or infections, it's essential to precisely measure the core body temperature during targeted temperature control when spontaneous circulation has returned. Previous approaches on the other hand, are intrusive and difficult to use. The usual technique, an oesophageal thermometer, was compared to a disposable non-invasive temperature sensor that used the heat flux methodology. This research indicates that, non-invasive disposable sensors used to measure core body temperature are very reliable when used for targeted temperature control after overcoming a cardiac arrest successfully. The non-invasive method of temperature measurement has somewhat greater accuracy than the invasive approach. The results of this study must be confirmed by more clinical research with various sensor types to figure out if the bounds of agreement could be increased. This will ensure that the findings are accurate based on core temperature.

Target Temperature Control in Patients with Burns

Severe burns lead to a persistent hypermetabolic response of the organism with significantly increased resting energy turnover, multi-organ dysfunction, muscle breakdown and increased risk of infection. Elevated core and skin temperatures are characteristic. A further increase in the metabolic rate can be triggered by heat losses, for which these patients are particularly predisposed due to high heat dissipation via evaporation of moisture and impairment of the thermoregulatory and insulating properties of the burnt skin. This is especially true in all treatment situations with exposure to large, uncovered skin surfaces, such as primary care, dressing changes in the intensive care unit and surgery with extensive sterile operating field. It has been shown that hypothermia is associated with numerous risks for the burn patient. Consistent heat management with measurement of the core body temperature and application of external and internal heat protection measures is recommended. Traditionally, an increase in room temperature is used here. However, this effective measure is limited by the resilience of the intensive care practitioners and the surgeons. To avoid perioperative hypothermia, strict surgical planning with limitation of the duration of surgery and close intraoperative communication about the risk of hypothermia are of particular importance.The differentiation between accepted temperature increase and infectious fever is often only possible by the inclusion of further examination findings. The criterion for sepsis is a temperature above 39 °C or below 36.5 °C.

Temperature control in critically ill patients with fever: A meta-analysis of randomized controlled trials.

Fever is frequently encountered in ICU. It is unclear if targeted temperature control is beneficial in critically ill patients with suspected or confirmed infection. We conducted a systemic review and meta-analysis to answer this question. We systematically reviewed major databases before January 2020 to identify randomized controlled trials (RCTs) that compared antipyretic with placebo for temperature control in non-neurocritical ill adult patients with suspected or confirmed infection. Outcomes of interest were 28-day mortality, temperature level, hospital mortality, length of stay, shock reversal, and patient comfort. 13 RCTs enrolling 1963 patients were included. No difference in 28-day mortality between antipyretic compared with placebo (risk ratio [RR] 1.03; 95% CI 0.79-1.35). Lower temperature levels were achieved in the antipyretic group (MD [mean difference] -0.41; 95% CI -0.66 to -0.16). Antipyretic use did not affect the risk of hospital mortality (RR 0.97; 95% CI 0.73-1.30), ICU length of stay (MD -0.07; 95% CI -0.70 to 0.56), or shock reversal (RR 1.11; 95% CI 0.76-1.62). Antipyretic therapy effectively reduces temperature in non-neurocritical ill patients but does not reduce mortality or impact other outcomes.

Study of PbiO2 Variation by Body Temperature and Capnia in Severe Head Trauma Patients Treated With Targeted Temperature Control

Study of PbiO2 Variation by Body Temperature and Capnia in Severe Head Trauma Patients Treated With Targeted Temperature Control

Long-term survival in out-of-hospital cardiac arrest patients treated with targeted temperature control at 33 °C or 36 °C: A national registry study

AimThere are limited data on long-term outcome in out-of-hospital cardiac arrest patients following the treatment shift of target temperature management (TTM) from 33 °C to 36 °C outside the controlled settings of randomised trials. The aim of this study was to evaluate the adherence to TTM guidelines after the publication of the TTM trial and if the change in temperature level influence six-month survival. MethodsOHCA patients admitted to intensive care units (ICU) and recorded in the Swedish Intensive Care Registry (January 2010–March 2016) were included. Each ICU in Sweden provided information on their TTM target (i.e. 33 °C [TTM33] or 36 °C [TTM36]) used and the date of shift to 36 °C. The primary outcome was six-months survival. Multivariate logistic regression and propensity score match was used to adjust for confounders. ResultsIn total, 2899 OHCA patients from 69 ICUs were assessed; of those, 1038 patients were treated with TTM (TTM33, n = 755 and TTM36, n = 283). Patients receiving any TTM decreased during the study period from 70.5% to 54.5% (p for trend <0.001). There was no significant difference in six-month survival between the TTM33 (47.2%) and the TTM36 (47.3%) groups (adjusted OR 1.12 [0.80–1.56]. In the propensity score matched analysis the six-months survival was 52.7 vs 47.3 %, OR 1.29 [0.90–1.85]). ConclusionsThe proportion of patients receiving therapeutic hypothermia in Sweden has decreased significantly since the publication of the TTM-trial indicating lower adherence to guidelines. This was not associated with any significant difference in long term outcome.

Computer Assisted E-Laboratory using LabVIEW and Internet-of-Things Platform as Teaching Aids in the Industrial Instrumentation Course

Nowadays, the emerging trend of utilizing the internet technology to improve teaching methods has caught the attention of many researchers. The education sector is the particular sector which has been getting the influence to implement more advanced teaching methods, and this can be seen through the application of the monitoring system, remote control, and even data acquisition through the Internet. Therefore, this study demonstrates the development of the interactive system via the Internet for the remote access to the equipment known as LD-Didactic temperature system which is used in the laboratory. This particular system is developed using an Arduino-Espresso8266 and LabVIEW platform which is integrated with Blynk software in order to remotely control the Proportional, Integral, and Derivative (PID) setting. Furthermore, the proposed framework is specifically focused on the PID temperature control system, which allows students to learn and simulate the concept of the control scheme by adjusting suitable parameter gains. Moreover, the system evaluation demonstrates the functionality and ability of direct controlling, monitoring, and tracking in order to achieve the targeted temperature control. These three strategies ensure the reproducibility of the experiment for the implementation in different systems. Last but not least, the designed system illustrates that full integration of the system with the internet platform provides students with the underlying knowledge of fundamentals, graphic visualization, and simulation practices. These will subsequently facilitate the learning process of the students.

Precise Control of Target Temperature Using N6-Cyclohexyladenosine and Real-Time Control of Surface Temperature.

Targeted temperature management is standard of care for cardiac arrest and is in clinical trials for stroke. N6-cyclohexyladenosine (CHA), an A1 adenosine receptor (A1AR) agonist, inhibits thermogenesis and induces onset of hibernation in hibernating species. Despite promising thermolytic efficacy of CHA, prior work has failed to achieve and maintain a prescribed target core body temperature (Tb) between 32°C and 34°C for 24 hours. We instrumented Sprague-Dawley rats (n = 19) with indwelling arterial and venous cannulae and a transmitter for monitoring Tb and ECG, then administered CHA via continuous IV infusion or intraperitoneal (IP) injection. In the first experiment (n = 11), we modulated ambient temperature and increased the dose of CHA in an attempt to manage Tb. In the second experiment (n = 8), we administered CHA (0.25 mg/[kg·h]) via continuous IV infusion and modulated cage surface temperature to control Tb. We rewarmed animals by increasing surface temperature at 1°C h-1 and discontinued CHA after Tb reached 36.5°C. Tb, brain temperature (Tbrain), heart rate, blood gas, and electrolytes were also monitored. Results show that titrating dose to adjust for individual variation in response to CHA led to tolerance and failed to manage a prescribed Tb. Starting with a dose (0.25 mg/[kg·h]) and modulating surface temperature to prevent overcooling proved to be an effective means to achieve and maintain Tb between 32°C and 34°C for 24 hours. Increasing surface temperature to 37°C during CHA administration brought Tb back to normothermic levels. All animals treated in this way rewarmed without incident. During the initiation of cooling, we observed bradycardia within 30 minutes of the start of IV infusion, transient hyperglycemia, and a mild hypercapnia; the latter normalized via metabolic compensation. In conclusion, we describe an intravenous delivery protocol for CHA at 0.25 mg/(kg·h) that, when coupled with conductive cooling, achieves and maintains a prescribed and consistent target Tb between 32°C and 34°C for 24 hours.

Characteristics and outcomes of out-of-hospital sudden cardiac arrest according to the time of occurrence

PurposeThe impact of time of occurrence has been extensively evaluated for in-hospital cardiac arrests but less for Out-of-Hospital Cardiac Arrests (OHCA). We assessed the impact of the time of occurrence on the characteristics and prognosis of OHCA. MethodsUsing data from the Paris Sudden Cardiac Death Expertise Center prospective study that includes all OHCA in the Paris Area, we compared characteristics and outcomes of off-hours OHCA (nights and days off) to regular-hours OHCA between 2011 and 2014. ResultsAmong a total of 9834 OHCA (70.0±17years old, 62.1% males), off-hours OHCA accounted for 63.4%. Although bystanders were more often present (74.4 vs. 72.1%, P=0.01), rates of bystander CPR (46.7 vs. 50.6%, P=0.001) and AED use (1.0 vs. 1.9%, P=0.01) were lower during off-hours. While EMS arrival delays were similar, patients were less often in shockable rhythm (16.3 vs. 19.1%, P<0.0001), and return of spontaneous circulation was less frequent (27.5 vs. 31.1%, P<0.0001). There was no difference in rates of targeted temperature control (54.8 vs. 54.7%, P=0.75), coronary angiography (57.3 vs. 58.2%, P=0.68) and angioplasty use (32.2 vs. 35.6%, P=0.22). Survival at hospital discharge was lower (4.7 vs. 6.5%, P<0.0001) during off-hours. After adjusting for potential confounders, time of occurrence was not associated with worse outcome (OR 0.85, 95% CI 0.69–1.06, P=0.15), and bystander-initiated CPR, shockable initial rhythm and AED use were the main survival predictors (P<0.0001). ConclusionOff-hours OHCA have a 30% lower survival rate, mainly due to differences in initial management (bystander CPR and AED use), illustrating the need to improve bystanders' responsiveness in all circumstances.

Coronary angiography after cardiac arrest: Rationale and design of the COACT trial

Ischemic heart disease is a major cause of out-of-hospital cardiac arrest. The role of immediate coronary angiography (CAG) and percutaneous coronary intervention (PCI) after restoration of spontaneous circulation following cardiac arrest in the absence of ST-segment elevation myocardial infarction (STEMI) remains debated. We hypothesize that immediate CAG and PCI, if indicated, will improve 90-day survival in post-cardiac arrest patients without signs of STEMI. In a prospective, multicenter, randomized controlled clinical trial, 552 post-cardiac arrest patients with restoration of spontaneous circulation and without signs of STEMI will be randomized in a 1:1 fashion to immediate CAG and PCI (within 2 hours) versus initial deferral with CAG and PCI after neurological recovery. The primary end point of the study is 90-day survival. The secondary end points will include 90-day survival with good cerebral performance or minor/moderate disability, myocardial injury, duration of inotropic support, occurrence of acute kidney injury, need for renal replacement therapy, time to targeted temperature control, neurological status at intensive care unit discharge, markers of shock, recurrence of ventricular tachycardia, duration of mechanical ventilation, and reasons for discontinuation of treatment. The COACT trial is a multicenter, randomized, controlled clinical study that will evaluate the effect of an immediate invasive coronary strategy in post-cardiac arrest patients without STEMI on 90-day survival.

Effect of therapeutic hypothermia and targeted temperature control after out of hospital cardiac arrest

L’hypothermie therapeutique est une des strategies ayant montre son efficacite dans l’amelioration de la survie et du pronostic neurologique chez les patients comateux dans les suites d’un arret cardiaque. Elle etait recommandee ces dix dernieres annees par les differentes societes savantes internationales. Toutefois, de nouvelles etudes ont remis en cause son efficacite et mene en 2015 a quelques ajustements.

Precise attoliter temperature control of nanopore sensors using a nanoplasmonic bullseye.

Targeted temperature control in nanopores is greatly important in further understanding biological molecules. Such control would extend the range of examinable molecules and facilitate advanced analysis, including the characterization of temperature-dependent molecule conformations. The work presented within details well-defined plasmonic gold bullseye and silicon nitride nanopore membranes. The bullseye nanoantennae are designed and optimized using simulations and theoretical calculations for interaction with 632.8 nm laser light. Laser heating was monitored experimentally through nanopore conductance measurements. The precise heating of nanopores is demonstrated while minimizing the accumulation of heat in the surrounding membrane material.

Performance analysis of a novel control system for solar collectors coupled with sorption chillers

This paper presents work on a holistic approach for improving the overall design of solar cooling systems. Newly developed methods for hydraulics and control were used to redesign an existing pilot plant. Measurements taken from the newly developed system show that target temperature control leads to an 81% increase of the Solar Cooling Efficiency (SCE) factor compared to the original pilot system. In addition to the improvements in system design, new efficiency factors for benchmarking solar cooling systems are presented. The Solar Supply Efficiency (SSE) factor provides a means of quantifying the quality of solar thermal charging systems relative to the usable heat to drive the sorption process. The product of the SSE with the already established COP of the chiller, leads to the SCE factor which, for the first time, provides a clear and concise benchmarking method for the overall design of solar cooling systems.