Local Heating Device Research Articles

Thermal switch for localized heating based on spatial electric field distribution regulation

At present, the thermal switch for localized heating is becoming a hot research topic in MEMS packaging technology. A method of using a liquid-based thermal switch is proposed in this paper. A plate local heating device based on electric field distribution control is constructed, where a thermal liquid column can be formed under the action of the electric field. The electric field controls the formation and dissipation of the liquid column to realize the on-off and off-on function of the thermal switch. Through the control of the different conductive substrates in the plate, the localized heat transfer can be further realized, and the heat transfer position is precisely regulated. Furthermore, due to the fluidity of the liquid, the prepared thermal switch can also realize movable heating. The experimental results show that the heating time and speed can be controlled precisely by adjusting the driven voltage and the conductive area of the upper substrate.

Thermal comfort and energy conservation of a four-sided enclosed local heating device in a cold environment

It has been proven that local heating can satisfy the thermal comfort needs of people with low energy consumption. Previous research on local heating equipment has been conducted in artificial climate chambers rather than in naturally conditioned buildings. In this study, a four-sided enclosed local heating device was developed, and experiments were conducted to investigate the thermal comfort and corresponding energy consumption when 20 subjects (half male and half female) used this device in a naturally conditioned environment in winter (12–16 °C). The experimental results indicated that the overall thermal responses of the subjects stabilized after the local heating device was used for 15 min, which significantly improved the overall thermal responses of the subjects (p < 0.01); furthermore, female subjects preferred a warmer environment. The upper limbs and shanks had the most intense cold sensations in the upper and lower body, respectively. Compared with the condition without local heating, the difference in body temperature of the shank was significant (p < 0.01). In addition, the total heating power of the equipment was related to the number of heating plates turned on. The fitting results indicated that the thermoneutral temperatures when three and four heating plates were turned on were 15.7 °C and 13.5 °C, respectively. The study results contributed to providing a reference for solving heating problems in areas where there were no central-heating facilities.

Effects of local heating of body on human thermal sensation and thermal comfort

Cold climates are conductive to heavy reliance on mechanical heating, increasing energy consumption. The use of personalized local heating can save energy, but the thermal perception capabilities of different body parts to local heating remain unclear. In this study, 32 participants wore clothing with an insulation rating of 0.9 Clo in a cool environment maintained at 19 °C. Each of seven body parts (back, chest, belly, waist, buttock, knee, and foot) was locally heated for 15 min using a heating pad taped to the outside of the undergarment at a temperature of 32±1 °C. The overall and local subjective thermal perceptions were captured using a questionnaire. Local heating devices with fixed surface temperatures significantly improved thermal sensation and comfort in cool environments. Heating the waist was associated with a significant improvement in overall thermal perception (p < 0.05), while heating the knee and chest showed the least improvement. Heating the waist increased the overall thermal sensation from slightly cool (−0.78) to neutral (0.26) and the overall thermal comfort from slightly uncomfortable (−0.50) to slightly comfortable (0.47), which was better than heating the foot. The effect of local heating was different between genders, with improvements being characterized as increased thermal sensation for men and increased thermal comfort for women. Local heating also reduced the heart rate, again with this reduction varying with the body part being heated. The acceptability of local heating was 81%, showing that it can be widely used in practice.

Disparities of indoor temperature in winter: A cross-sectional analysis of the Nationwide Smart Wellness Housing Survey in Japan.

The WHO Housing and health guidelines recommend a minimum indoor temperature of 18°C to prevent cold‐related diseases. In Japan, indoor temperatures appear lower than in Euro‐American countries because of low insulation standards and use of partial intermittent heating. This study investigated the actual status of indoor temperatures in Japan and the common characteristics of residents who live in cold homes. We conducted a nationwide real‐world survey on indoor temperature for 2 weeks in winter. Cross‐sectional analyses involving 2190 houses showed that average living room, changing room, and bedroom temperatures were 16.8°C, 13.0°C, and 12.8°C, respectively. Comparison of average living room temperature between prefectures revealed a maximum difference of 6.7°C (Hokkaido: 19.8°C, Kagawa: 13.1°C). Compared to the high‐income group, the odds ratio for living room temperature falling below 18°C was 1.38 (95% CI: 1.04‐1.84) and 2.07 (95% CI: 1.28‐3.33) for the middle‐ and low‐income groups. The odds ratio was 1.96 (95% CI: 1.19‐3.22) for single‐person households, compared to households living with housemates. Furthermore, lower room temperature was correlated with local heating device use and a larger amount of clothes. These results will be useful in the development of prevention strategies for residents who live in cold homes.

Experimental comparison of local direct heating to improve thermal comfort of workers

This study aims to investigate the effect of wearable local heating devices on the thermal comfort of workers doing handwork in cold environments. Experiments were carried out by using local radiant heating, ankle heating, wrist heating, torso heating, and combined heating, which were compared with no heating conditions. Twenty subjects participated in the experiments under air temperature conditions of 13 and 15 °C. The participants were asked to perform three activities: standing, assembling screws, and assembling small shelves. Subjective questionnaires pertaining to overall thermal sensation, local thermal comfort of hands, and thermal comfort were collected. The mean skin temperature (MST) was measured. The results show that some of the local direct heating improves subjects' overall thermal sensation, local thermal sensation of hands, and thermal comfort significantly. These methods include torso heating and the combined heating. Moreover, subjects’ MST and working efficiency are also increased. The working efficiency is found to be related closely to local thermal sensation of hands. Although wrist heating does not improve the thermal sensation significantly, it improves the thermal sensation of hands and the work efficiency effectively. The analysis shows that local thermal sensation of hands is linearly related to the overall thermal sensation. When the local thermal sensation of hands is neutral, the overall thermal sensation would be slightly warm, and subjects would feel more comfortable. Compared to local radiant heating, these wearable heating devices are more efficient, in that they improve thermal comfort and working efficiency better with a lower energy cost.

Demand and efficiency evaluations of local convective heating to human feet and low body parts in cold environments

A good practice of the personal comfort system is to extend acceptable comfort zones and achieve energy savings in buildings; while quite few studies look into the use of local heating in winter. This study was designed to understand the demands of the local heating and the appropriate devices in the Hot Summer and Cold Winter (HSCW) region of China. This was achieved by combining online survey and two series of experiments in a climate chamber. Results from survey revealed that various heating devices were employed by occupants in buildings; the feet and lower body parts were the most preferred parts to be heated in winter. A local heating device was designed to supply warm air to subjects' feet and calves directly. In Experiment I with ambient temperatures of 16 °C and 18 °C, no remarkable improvements were found by local heating, due to higher clothing insulation (1.3clo) and a neutral thermal sensation of subjects. When decreasing to 14 °C and 12 °C in Experiment II, subjects’ thermal sensation for both feet and overall were increased significantly when local heating was supplied. The high heating efficiency was suggested with decreasing ambient temperature under 16 °C and increasing supply air temperature to 30 °C-40 °C. The findings provide a support to design local heating devices and manage personal comfort for occupants. The outcomes are expected to relieve demands on winter heating in the HSCW region and trade off the building energy quota target for China.

Study on the effects of chair heating in cold indoor environments from the perspective of local thermal sensation

A personal comfort system for heating has the potential to maintain or even enhance the occupants’ thermal comfort in cold indoor environments. In this study, the effects of a chair with a heatable backrest and seat cushions were tested by subject experiments at 14 °C, 16 °C, and 18 °C in a climate chamber. The results reveal that compared to the well-insulated chair, the additional active heating has no significant advantage for the overall thermal comfort at 16 °C and 18 °C and has only a limited effect on improving overall thermal sensation and comfort at 14 °C. Due to the production of heat by the human body itself, the back and buttocks, which are the body parts in contact with the chair, would not feel cold as long as the chair's thermal insulation is sufficient. The cold feelings of extremities are the coldest in a cold indoor environment and the main source of the overall cold feeling. Additionally, chair heating cannot improve the local thermal sensation of the extremities, which limits the effect of the chair heating. Therefore, relevant local heating devices should be developed around the extremities. For the chair, sufficient insulation can achieve an effect similar to active heating on thermal comfort when the ambient temperature is not lower than 16 °C.

Development of small sized friction stir welding equipment for hand operated welding

Friction stir welding (FSW) is widely used in various industrial fields. However, high tiffness is required for FSW equipment which has to withstand high applied load and tool torque and therefore, the equipment becomes large sized. It is difficult to employ FSW for site welding such as repair welding and/or manual welding. The authors made a prototype of FSW apparatus equipped with a counterbalanced tool and a local heating device. The relationship between the applied load and welding parameters was investigated and it was found that the force in the welding direction, Fx is reduced to 70 N or less and that in the transverse direction Fy is to 50 N or less. The combined use of the prototype equipment with a counterbalanced tool and the local heating is very effective to downsize FSW equipment.

Improved pharmacokinetic and pharmacodynamic profiles of insulin analogues using InsuPatch, a local heating device

Previous studies have shown that heating the insulin injection site may accelerate insulin absorption. We investigated the pharmacological profile of insulin administered with InsuPatch, a local skin-heating device. In this randomized, crossover study carried out in 56 subjects with type 1 diabetes treated with insulin pump [mean age 32 ± 13.5 years; 23 women; HbA1c :7.8 ± 0.9% (62 ± 10 mmol/mol) (mean+/-standard deviation)]. Euglycemic glucose clamps were performed after administration of 0.15 units/kg of short-acting insulin analogues. Each subject underwent three clamp procedures: two with the InsuPatch device (day 1 and day 3) and one without the device (day 1 control). The primary endpoints were the following: (1) the change in the area under the curve (AUC) of insulin during the first 60 min post-insulin bolus on day 1 with the InsuPatch device versus day 1 control and (2) parameters to assess the safety of using the device. The area under the curve of insulin during the initial 60 min (insulin AUC(0-60)) after insulin bolus was increased by 29.7 ± 7% on day 1 InsuPatch versus day 1 control (p < 0.01). Maximal post-insulin bolus concentration was 57 mU/L on day 1 InsuPatch versus 47.6 mU/L on day 1 control (p < 0.01). On day 3 InsuPatch, insulin AUC(0-60) was increased by 27.9 ± 72% versus day 1 InsuPatch (p < 0.01). Maximal insulin concentration was 70.4 mU/L versus 57 mU/L, respectively (p = 0.05). The use of the heating device upon administration of short-acting insulin analogues in pump-treated type 1 diabetic patients was found to enhance insulin absorption. This heating device may therefore serve to achieve better meal insulin coverage.

Elevated local skin temperature impairs cutaneous vasoconstrictor responses to a simulated haemorrhagic challenge while heat stressed

During a simulated haemorrhagic challenge, syncopal symptoms develop sooner when individuals are hyperthermic relative to normothermic. This is due, in part, to a large displacement of blood to the cutaneous circulation during hyperthermia, coupled with inadequate cutaneous vasoconstriction during the hypotensive challenge. The influence of local skin temperature on these cutaneous vasoconstrictor responses is unclear. This project tested the hypothesis that local skin temperature modulates cutaneous vasoconstriction during simulated haemorrhage in hyperthermic humans. Eight healthy participants (four men and four women; 32 ± 7 years old; 75.2 ± 10.8 kg) underwent lower-body negative pressure to presyncope while heat stressed via a water-perfused suit sufficiently to increase core temperature by 1.2 ± 0.2 °C. At forearm skin sites distal to the water-perfused suit, local skin temperature was either 35.2 ± 0.6 (mild heating) or 38.2 ± 0.2 °C (moderate heating) throughout heat stress and lower-body negative pressure, and remained at these temperatures until presyncope. The reduction in cutaneous vascular conductance during the final 90 s of lower-body negative pressure, relative to heat-stress baseline, was greatest at the mildly heated site (-10 ± 15% reduction) relative to the moderately heated site (-2 ± 12%; P = 0.05 for the magnitude of the reduction in cutaneous vascular conductance between sites), because vasoconstriction at the moderately heated site was either absent or negligible. In hyperthermic individuals, the extent of cutaneous vasoconstriction during a simulated haemorrhage can be modulated by local skin temperature. In situations where skin temperature is at least 38 °C, as is the case in soldiers operating in warm climatic conditions, a haemorrhagic insult is unlikely to be accompanied by cutaneous vasoconstriction.

Altered thermal hyperaemia in human skin by prior desensitization of neurokinin-1 receptors.

The neuropeptides substance P (SP) and calcitonin gene-related peptide are believed to be involved in the axon reflex-mediated component of cutaneous thermal hyperaemia, but no studies have specifically addressed this issue. The purpose of this study was to determine whether neurokinin-1 receptors, which preferentially bind SP, contribute to the axon reflex component of cutaneous thermal hyperaemia. Nine subjects were equipped with four microdialysis fibres, and each fibre received one of the following four treatments: (1) lactated Ringer's solution (control); (2) 10 mml-NAME to inhibit nitric oxide synthase; (3) 10 μm SP; or (4) 10 μm SP + 10 mml-NAME. Skin blood flow was monitored via laser-Doppler flowmetry, and local skin temperature was controlled using local heating devices. Sites 3 and 4 were perfused with 10 μm SP for 15 min at a rate of 4 μl min(-1), and the ensuing vasodilatation was allowed to return to baseline. Following SP-induced vasodilatation, all skin sites were locally heated from a baseline temperature of 33°C to 42°C at a rate of 0.5°C every 5 s. Cutaneous vascular conductance (CVC) was calculated as skin blood flow/mean arterial pressure and normalized to the maximal value (%CVC(max)) via 28 mm nitroprusside and local heating to 43°C. The initial peak did not differ between control (79 ± 3%CVC(max)) and SP-only sites (79 ± 2%CVC(max)). The initial peaks at the l-NAME (43 ± 3%CVC(max)) and SP + l-NAME sites (53 ± 3%CVC(max)) were significantly reduced compared with both the control and the SP-only sites (P < 0.001 for both), and l-NAME sites were attenuated compared with SP + l-NAME sites (P < 0.01). There was no observable nadir response at sites pretreated with SP. Compared with control sites (57 ± 4%CVC(max)), the nadirs at the l-NAME (14 ± 2%CVC(max)) and the SP + l-NAME sites (31 ± 5%CVC(max)) were significantly reduced (P < 0.01 for all conditions). l-NAME significantly reduced the nadir compared with SP + l-NAME (P < 0.01). Plateau CVC values did not differ between control (86 ± 3%CVC(max)) and SP sites (91 ± 1%CVC(max)). At l-NAME (36 ± 4%CVC(max)) and SP +l-NAME sites (56 ± 6%CVC(max)), plateau CVC was significantly reduced compared with control and SP-only sites (P < 0.01 for all conditions). The plateau at l-NAME sites was significantly reduced compared with SP + l-NAME sites (P < 0.01). These data suggest that neurokinin-1 receptors contribute to both the axon reflex component and the secondary plateau phase of cutaneous thermal hyperaemia.

Effect of a local heating device on insulin and glucose pharmacokinetic profiles in an open-label, randomized, two-period, one-way crossover study in patients with type 1 diabetes using continuous subcutaneous insulin infusion

Background: Reducing postprandial hyperglycemia and hypoglycemia is a major challenge in the treatment of patients with diabetes. Studies suggest that heating the insulin injection site may accelerate insulin absorption. InsuPatch™ (InsuLine Medical Ltd., Petach-Tikva, Israel) is a device intended to accelerate subcutaneous insulin delivery using an insulin pump by locally warming the infusion site. Objective: The aim of this study was to assess the effect of the InsuPatch device on the pharmacokinetics of short-acting insulin analogues and on postprandial glycemia. Methods: This was an open-label, randomized, 2-period, 1-way crossover study using a meal tolerance test (MTT) protocol in subjects with type 1 diabetes mellitus aged 18 to 65 years with glycosylated hemoglobin (HbA 1c) of 6% to 12%, who were using continuous subcutaneous insulin infusion (CSII) therapy (insulin lispro or aspart). A bolus of insulin 0.15 U/kg was delivered immediately before a standardized liquid meal. The effect of the device on insulin absorption and postprandial glucose excursions was tested by measuring blood glucose and insulin concentration profiles with and without the operation of the device. Adverse events (AEs) were monitored during the 2 study visits. The infusion site was visually inspected at the end of each study. All AEs were recorded in the case-report form. Results: The MTT protocol was performed in 17 white patients with type 1 diabetes (sex, male/female, 7/10; mean age, 31.8 years [range, 18–53 years]; mean body mass index, 25.6 kg/m 2 [range, 20.0–39.4 kg/m 2]; and mean HbA 1c, 7.1% [range, 5.8%–9.3%]). The mean (SD) postprandial glucose excursion AUC at 120 minutes after the meal was significantly reduced in the group that used the device compared with the group that did not (104 [65] vs 155 [56] mg/dL/h; P < 0.005). Plasma insulin was measured randomly in 9 of the 17 subjects. Use of the device was associated with significant reductions in mean (SD) T max (45 [28] vs 78 [35] minutes) and time to half-maximum concentration (T 50%max) (20 [11] vs 28 [10] minutes; both, P < 0.05). Insulin AUC increased significantly in the group that used the device compared with the group that did not at 30 (21 [6] vs 33 [16] mU/L/h), 60 (55 [12] vs 80 [28] mU/L/h), and 90 (93 [19] vs 118 [31] mU/L/h) minutes after administration (all, P < 0.05). Cmax also increased significantly (118 [35] vs 86 [16] mU/L [38%]; P < 0.05). Conclusion: In this pilot study, use of the InsuPatch was associated with significant decreases in T max and T 50%max and increases in insulin AUC and C max of subcutaneous infused rapid-acting insulin analogues, resulting in a lower postprandial glucose excursion in these patients with type 1 diabetes mellitus treated with CSII.

AZ31 합금 판재의 온간 점진 성형에 관한 연구

A fundamental study on warm incremental forming of a magnesium alloy sheet has been carried out. In order to enhance the incremental formability of the magnesium alloy sheet, a local heating device was newly designed and manufactured. Through the incremental forming tests of AZ31 under various forming conditions, the effects of process parameters such as the temperature, feeding depth per cycle, and inclination angle on the incremental formability of AZ31 were investigated. In addition, conventional FLDs at elevated temperatures were constructed experimentally and applied to predict the forming failure.

Micromachined Thermal Effect Array by Joule Heating for Bio Applications

We have developed a micro local heating device for bio applications using micro-electro-mechanical systems (MEMS) technology. The device has a two-dimensional microdish array, which contains a series of diodes. The microdish array is fabricated by means of a combination of complementary metal–oxide–semiconductor (CMOS) technology and MEMS post-processing. The microdish array has a miniature cavity for thermal separation from substrate. These microdish arrays can be generated by a large forward current based on Joule heating. In this paper, we describe the direct heating of the whole microdish array and just an arbitrary portion of the microdish consisting of the device by Joule heating. In the localized selective heating, the highest temperature, 62.6 °C, from all the dishes was confirmed. More than twice the heat effect was achieved in heating an arbitrary portion compared with heating the whole microdish.

Motion control of single F1-ATPase rotary biomolecular motor using microfabricated local heating devices

Biomolecular motors are major targets in single-molecule studies, which reveal molecular behaviors usually hidden in the emsemble- and time-averaging of bulk experiments. Methods for rapid experimental condition control during single-biomolecule observation are a key technology to elucidate the molecular mechanisms of proteins. One of the most promising methods is real-time rapid temperature alternation. A microheater and a microthermosensor were integrated on the glass plate for controlling the temperature locally; the maximum response speeds were 71.5 and 56.9K∕s for temperature rise and fall, respectively. Rapid temperature alternation with microfabricated thermodevice allowed rapid and reversible angular velocity control of a single F1-ATPase, a rotary biomolecular motor. The rapid control of the temperature enabled us to perform rotation assay at temperatures higher than that would “normally” denature them. This revealed that the torque of F1-ATPase seems to increase at higher temperatures with the increasing rate of 4% per 10°C. This method and knowledge for controlling the biomolecular motor can also be applied to future hybrid organic-inorganic nanosystems, which use biomolecular motors as nanoactuators.

1108 極微細ヒータを用いた生体分子モータの回転速度制御 : バイオ機能分子と無機微細加工構造物に融合による新機能素子の創造に向けて(要旨講演,マイクロメカトロニクス)

1108 極微細ヒータを用いた生体分子モータの回転速度制御 : バイオ機能分子と無機微細加工構造物に融合による新機能素子の創造に向けて(要旨講演,マイクロメカトロニクス)

Dual-modality phased array systems for hyperthermia cancer therapy

External ultrasound (US) phased arrays, as applied to hyperthermia cancer therapy, are generally local heating devices, whereas external radio-frequency (RF) electromagnetic (EM) phased array applicators are primarily designed for regional heating. Clinical applications of external ultrasound heating devices are presently limited to smaller tumors, and the inclusion of an external RF/EM applicator increases the size of the heated volume. When these two modalities are combined in a hybrid RF/US phased array structure, uniform heating is facilitated in larger tumors. This is demonstrated in computer simulations of thermal therapy in the breast, where adding an external RF/EM component to an ultrasound phased array in a hybrid structure produces temperatures of 43&amp;lt;th&amp;gt;°C in nearly half of a 9-cm-diam tumor volume. If applied alone, neither modality achieves 43&amp;lt;th&amp;gt;°C in such a large volume without overheating intervening tissues. This result is demonstrated in two hybrid RF/US applicator prototypes designed for hyperthermia treatments of locally advanced breast cancer. In each example, hybrid RF/US phased arrays achieve higher temperatures in larger tumor volumes by selectively delivering power to different regions in the tumor with each modality.