Human Body Heat Research Articles

Durable Moisture-wicking and Fast-dry Polyester Fabric Prepared by UV-induced Click Reaction

Polyester (PET) fabric is an important fabric to make sportswear due to its good mechanical strength, wear resistance and low cost, but poor hygroscopicity will accumulate moisture and excessive heat of human body which thereby causing thermo-physiological dicomfort. To obtain satisfying moisture-wicking, hydroscopic and fast-dry properties, facile and efficient single-sided click chemistry was used to substitute traditional methods. Firstly, PET fabric was alkali treated and modified with 3-mercaptopropyltrimethoxysilane to obtain thiol groups. Then it was gradiently grafted with potassium 3-sulfopropyl acrylate by thiol-ene click chemistry under single-sided ultraviolet (UV) irradiation to enlarge effects. The reaction was proved by FTIR and Ellman method, the surface morphology was observed by SEM, and the mass loss at different temperatures in thermalgravimetry (TG) test illustrated the quantity change of grafting. The results demonstrated that the resultant fabric has good performance of moisture absorbing and sweat releasing, fast drying as well as outstanding antistatic and soil release properties.

Large-Area Laying of Soft Textile Power Generators for the Realization of Body Heat Harvesting Clothing

This paper presents the realization of a flexible thermoelectric (TE) generator as a textile fabric that converts human body heat into electrical energy for portable, low-power microelectronic products. In this study, an organic non-toxic conductive coating was used to dip rayon wipes into conductive TE fabrics so that the textile took advantage of the TE currents which were parallel to the temperature gradient. To this end, a dyed conductive cloth was first sewn into a TE unit. The TE unit was then sewn into an array to create a temperature difference between the human body and the environment for TE power harvesting. The prototype of the TE fabric consisted of 48 TE units connected by conductive wire over an area of 275 × 205 mm2, and the TE units were sewn on a T-shirt at the chest area. After fabrication and property tests, a Seebeck coefficient of approximately 20 μV/K was measured from the TE unit, and 0.979 mV voltage was obtained from the T-shirt with TE textile fabric. Since the voltage was generated at a low temperature gradient environment, the proposed energy solution in actual fabric applications is suitable for future portable microelectronic power devices.

Efficient Debundling of Few-Walled Carbon Nanotubes by Wrapping with Donor-Acceptor Polymers for Improving Thermoelectric Properties.

Organic thermoelectric (TE) materials have great potential as sustainable energy sources for powering flexible and wearable electronic devices via harvesting of human body heat. Recent advances in soluble conjugated polymer/carbon nanotube (CNT) composites have facilitated achievement of high TE power factors. However, the effects of conjugated polymers on the debundling and electrical percolation of CNTs and on the TE properties of their composites are not yet fully understood. Herein, we introduce a novel type of polymer/CNT composite composed of a donor-acceptor (D-A)-type polymer and few-walled CNTs (FWCNTs). Three kinds of D-A polymers are employed to disperse FWCNTs, and the photophysical, morphological, and TE properties of the resulting polymer/FWCNT composites are compared with those of composites composed of FWCNTs dispersed with conventional donor-only poly(3-hexylthiophene). The results reveal that the strong intermolecular interaction forces and high backbone planarity of the D-A polymers facilitate effective debundling of FWCNTs, which results in much smaller bundle sizes. Consequently, the D-A polymer/FWCNT composite films show superior electrical percolation and TE performances with improved power factors of up to 459 μW/mK2. Finally, we demonstrate the feasibility of the D-A polymer/FWCNT composites for use in the fabrication of a flexible TE generator, which shows a maximum power output of 210 nW at a temperature gradient of 20 K.

Thin-Film π-Type Micro TEG Using Vacuum/Insulator-Hybrid Isolation with Convex-Shape Hot-Plate Module Structure for Wearable Device Applications

Design optimization and performance of a micro thermoelectric generator (μTEG) using human body heat are investigated. A newly introduced thin-film π-type μTEG module structure using vacuum/insulator-hybrid thermal isolation with the convex-shape hot plate is useful to achieve a high thermal resistance of the module and also to suppress the unwanted heat flow passing through the supportive wall structure for the vacuum isolation. The optimum design of this μTEG module can exhibit sufficiently high output power suitable for a power source of self-powered wearable devices.

高温低湿空調システムに関する研究 （その１）温湿度の違いが人体放熱量と温冷感に与える影響の検討

高温低湿空調システムに関する研究 （その１）温湿度の違いが人体放熱量と温冷感に与える影響の検討

Human Body Heat Based Thermoelectric Harvester with Ultra-Low Input Power Management System for Wireless Sensors Powering

Energy harvesting (EH) technique has been proposed as a favorable solution for addressing the power supply exhaustion in a wireless sensor node and prolong the operating time for a wireless sensor network. Thermoelectric energy generator (TEG) is a valuable device converting the waste heat into electricity which can be collected and stored for electronics. In this paper, the thermal energy from human body is captured and converted to the low electrical energy by means of thermoelectric energy harvester. The aim of presented work is utilizing the converted electricity to power the related electronic device and to extend the working life of a sensor node. Considering the related characteristics of TEG used for human, a type of a novel power management system is designed and presented to harvest generated electricity. The proposed circuit is developed based on off-the-shelf commercial chips, LTC3108 and BQ25504. It can accept the lowest input voltage of 20 mV, which is more suitable for human thermoelectric energy harvesting. Through experiments, developed energy harvesting system can effectively power the sensor to intermittently transmit the data as well as perform the converted energy storage. Compared to the independent commercial chips applications and other microcontroller-based energy harvesting systems, the designed thermoelectric energy harvester system presents the advantages not only in high energy storage utilization rate but also the ultra-low input voltage characteristic. Since the heat from human body is harvested, therefore, the system can possibly be used to power the sensor placed on human body and has practical applications such as physiological parameter monitoring.

Investigation of the Stabilization Mechanism of Air Stable n-Type Single-Walled Carbon Nanotubes Sheets Based on Adsorption Isotherm Measurements

In spite of the remarkable growth of microelectronics such as wearable devices, remote sensors, etc. On the market in recent years, almost all of them are still powered by batteries that are required to be recharged or replaced at stated periods. If these electronic devices can run continuously for an extended time without any external interference, the benefits would be further enhanced. One such solution is to produce energy from the human body heat, where the thermoelectric (TE) generation mechanism is used to generate electricity from temperature difference. The principle behind TE generation is the Seebeck effect. It is a phenomenon to produce potential difference from the temperature difference between the ends of a TE generator. The efficiency of this TE conversion can be evaluated by the figure of merit, ZT = S2σT/κ, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature, and κ is the thermal conductivity. TE generators with a high Seebeck coefficient, high electrical conductivity, and low thermal conductivity are expected to have good TE properties. To fabricate the TE devices, p- and n-type materials are necessary and the research of TE materials using inorganic semiconductors such as Bi2Te3 have been done for a long time as they illustrate high performance more than ZT = 1. However, these materials contain rare and toxic elements and they are difficult to process. Therefore, among the several candidates including conducting polymers, single-walled carbon nanotubes (SWNTs) are emerged as the promising candidate due to their non-toxicity, processability, remarkable electrical and thermal conductivity, potentially large Seebeck coefficient and light weight. However, due to air oxidation, SWNTs show only p-type semiconducting property in air. In the development of the SWNTs-based TE devices, instability of the n-type SWNTs has been a crucial issue, since n-type SWNT are easily oxidized due to an electrophilic chemisorption of oxygen on the charge polarization.1 Under such background, we have reported that air-stable n-type SWNTs can be formed by adsorbing 2-(2-methoxyphenyl)-1,3-dimethyl-2,3-dihydro-1H-benzo [d] imidazole (o-MeO-DMBI). However, the stabilization mechanism is not clear. herefore, in this research we studied the stabilization mechanism based on the adsorption isotherm measurements, where the SWNT sheets were dipped in the ethanol solution of o-MeO-DMBI in different concentrations at 25 ºC. From the adsorption isotherm, we revealed that SWNTs sheets adsorbed below monolayer of o-MeO-DMBI showed unstable in n-type, while SWNT sheets adsorption of o-MeO-DMBI showed stable n-type property over full coverage3. 1) Zhu, X.-Q.; Zhang, M.-T.; Yu, A.; Wang, C.-H.; Cheng, J.-P. J. Am. Chem. Soc. 2008, 130, 2501. 2) Nakashima, Y.; Nakashima, N.; Fujigaya, T. Synthetic. Metals. 2017, 76, 225. 3) Nakashima, Y.; Yamaguchi, R.; Fujigaya, T. submitted.

Thermal performance of a mine refuge chamber with human body heat sources under ventilation

This paper investigated the dynamic coupling heat transfer characteristics of rock and air in a Mine Refuge Chamber (MRC) under ventilation. In the current work, a comprehensive fifty-person MRC model combining human-body heat sources and ventilation is established, the proposed model is validated against available experimental data with deviation less than 4%. Furthermore, sensitivity analysis is performed to investigate the influence of several control parameters such as heating rate, ventilation and wall area in a MRC through using numerical simulation. Results indicated that: (i) the heat transfer process in a MRC will reach a stage of air temperature slow increase (ATSI) in less than 0.5 h. The air temperature rises linearly with the square root of time during the ATSI stage; (ii) for a MRC built in a sandstone seam with an initial rock temperature of less than 27 °C, the average air temperature will not exceed 35 °C in 96 h when the ventilation volume rate is 0.3 m3/min per person; (iii) the rate of temperature rise in MRC is proportional to the rate of heat generation, but it is inversely proportional to the thermal conductivity, density and thermal capacity of the rock, as well as the ventilation volume rate and the wall area; (iv) an empirical correlation for the MRC average air temperature is developed while the supply air temperature equals to the initial rock temperature.

Integrated Cold-Start of a Boost Converter at 57mV using Cross-Coupled Complementary Charge Pumps and Ultra-Low-Voltage Ring Oscillator.

This paper demonstrates an on-chip electrical cold-start technique to achieve low-voltage and fast start up of a boost converter for autonomous thermal energy harvesting from human body heat. An improved charge transfer through high gate-boosted switches by means of cross-coupled complementary charge pumps enables voltage multiplication of the low input voltage during cold start. The start-up voltage multiplier operates with an on-chip clock generated by an ultra-low-voltage ring oscillator. The proposed cold-start scheme implemented in a general purpose 0.18μm CMOS process assists an inductive boost converter to start operation with a minimum input voltage of 57mV in 135 ms while consuming only 90 nJ of energy from the harvesting source, without using additional sources of energy or additional off-chip components.

Cell thermoregulation hypothesis: its origin, material basis, mechanisms and meaning

The accumulated knowledge about the chromosome structure, redundant DNA and an interphase nucleus inevitably raises, at least, two questions: (1) Why are there so much non-coding DNAs in chromosomes of higher eukaryotes and (2) what is the role of their organization in interphase nucleus on cellular function? These questions in cell biology are attracting increased attention as the genomes of higher eukaryotes are being sequenced. Based on investigations of chromosomal heterochromatin regions variability in human populations, condensed chromatin (CC), interphase nucleus and redundant non-coding DNAs in the genome, an attempt is made to justify the view of possible participation of CC in cell thermoregulation. CC, being the densest domains in a cell, apparently conducts heat between the cytoplasm and nucleus when there is a difference in temperature between them. Keywords: Cell Thermoregulation; Condensed Chromatin; Q-heterochromatin; C-heterochromatin; Human Body Heat Conductivity; Human Adaptation

A wearable microfluidic device for rapid detection of HIV-1 DNA using recombinase polymerase amplification

Although isothermal nucleic acid amplification is advantageous in pathogen detection in resource-limited settings, an electricity-dependent heating module is often required. Here, we developed a wearable microfluidic device combined with recombinase polymerase amplification (RPA) for simple and rapid amplification of HIV-1 DNA using human body heat. The human body temperature at the human wrist varied from 33 to 34 °C in the ambient environment, which is sufficient to perform RPA reactions. With the aid of a cellphone-based fluorescence detection system, this device detected HIV-1 DNA quantitatively ranging from 102 to 105 copies/mL with a log linearity of 0.98 in 24 min. These results demonstrate that this wearable point-of-care (POC) nucleic acid testing method is advantageous over traditional PCR and other isothermal nucleic acid amplification methods in terms of time, portability and independence on electricity. This wearable microfluidic device in conjunction with a cellphone-based fluorescence detection system can be potentially used for the detection of HIV-1 and adapted for POC detection of a broad range of infectious pathogens in resource-limited settings.

Controlled template-free in-situ polymerization of PEDOT for enhanced thermoelectric performance on textile substrate

Abstract The paper presents a simple one-bath template-free solution method to develop the conductive poly (3, 4-ethylenedioxythiophene) (PEDOT) with controlled morphological structures using various monomer to oxidant (PEDOT: FeCl 3 ) ratio of 1:3, 1:6 and 1:9 respectively for the preparation and growth on textile substrate. The results of the structural analysis showed that the polymerization process affected the formation of different shapes from nanofibers, nanotubes, and nanocubes. The spherical nanotubes changed their size and shape into 3D nanocubes at monomer/oxidant ratio of 1:6. The resultant structure considerably influenced the electrical conductivity, and thermoelectric performance of PEDOT coated textile substrate towards potential energy harvesting textile based thermoelectric Nanogenerator for energy harvesting from human body heat. This study demonstrates the new systematic approach for textile-based energy harvesting TE generator with enhanced thermoelectric performance.

Fabrication of Silver-Doped (Bi,Sb)₂Te₃ Thermoelectric Film Prepared from Ag Nanoparticles/Bi-Sb-Te Pastes.

Film-type thermoelectric generator (TEG) utilizing Bi-Te based paste has been highly considered as advanced power sources for the wearable electronic devices due to its light, thin and flexible characteristics when producing electricity from certain thermal resources such as human body heat. However, the application of the film-typed TEG has been often limited due to its low TE conversion efficiency caused by low electrical conductivity resulting from severe porosity. Thus, it is crucial to increase electrical properties via densification of the TE film. Here, we synthesized silver nanoparticle (AgNP)-dispersed (Bi,Sb)₂Te₃ (BSbT) powders to fabricate AgNP-BSbT pastes by adding organic binder. The synthesized AgNP-BSbT pastes were printed through a hand-painting process and were consolidated into Ag-doped BSbT (Ag-BSbT) thick film with a few hundreds μm with controlled 2-step heat treatment. The microstructures of Ag-BSbT films show abnormally elongated grains but also the amount of porosities in the film significantly decreased by addition of AgNP. As a result, it is confirmed that the 0.072 at% Ag-BSbT thick film exhibits power factor of 2.93 × 10-3 W/mK² at room temperature, which is comparable to that of practically utilized bulk materials. It is elucidated that the increase in power factor originates from the modulation between electrical conductivity and Seebeck coefficients due to increased hole carrier density at room temperature.

Bandage-like wearable flexible microfluidic recombinase polymerase amplification sensor for the rapid visual detection of nucleic acids

With the development of flexible advanced materials and microfluidic technology, wearable biosensors provide a new strategy for the continuous monitoring of health. In this study, a novel bandage-like wearable flexible microfluidic recombinase polymerase amplification (RPA) sensor was constructed for the rapid and visual detection of nucleic acids. This wearable sensor is triggered by human body heat (30°C-37 °C) and allows for visual nucleic acid (a conserved nucleic acid fragments of zika virus) detection within 10 min. The sensor displays good sensitivity and selectivity, with a detection limit of 10 copies/μL. The wearable sensor has exhibited well-defined accuracy when applied to testing clinical serum samples. In addition, the wearable RPA sensor was proved to be feasible by human trials under different daily activities. This wearable sensor of nucleic acids will probably be of great significance in the field of online pathogen detection for wounds, for tumour biomarker diagnosis, and for the detection of epidermal cell molecular lesions.

Cell Thermoregulation: Reality or just a logical Construction?

The existence of biological thermoregulation at the molecular and organism (physiological organ-based system of thermoregulation) levels is well known. The possibility of thermoregulation at the level of individual cells is discussed. By cell thermoregulation (CT) is meant the elimination of the temperature difference between the nucleus and cytoplasm, when, for one reason or another, the level of thermal energy in the nucleus becomes higher than of the cytoplasm. The CT hypothesis can shed light on some scattered facts and observations, known in different areas of biology and medicine, but without rational explanation. It is assumed that CT originated from the evolution of ncDNAs in the eukaryotic genome, and its material basis is condensed chromatin. Although the CT hypothesis has not yet been directly experimentally confirmed, nevertheless, its existence can be determined by indirect methods at the organism level. Keywords: Cell thermoregulation; Condensed chromatin; Chromosomal heterochromatin regions; Human body heat conductivity

Wi-Fi and GSM Based Motion Detection in Smart Home Security System

WiFi and Global System for Mobile Communication (GSM) based the smart home security system is a system that designed to improve security in most private housing. The main devices in this research are sensor for motion detection using Passive Infrared Sensor (PIR), Arduino Mega2560 as microcontroller board, NodeMCU V3 ESP8266 as WiFi development board that helps to prototype IoT product with few Lua script lines, or through Arduino IDE and then SIM800L as GSM module that also features GPRS support. The detection of motion is based on the principle of infrared radiation produced by human body heat which triggers a Passive Infrared Sensor (PIR). When the microcontroller received and processed the signal from human motion, then the trigger the buzzes the alarm, the microcontroller also activates the GSM module and sends SMS message to the user’s mobile phone device. This system enables to control the home by using android device, such as door, garage, and lamp in the rooms.

Prototype Pengaman Rumah Dari Bahaya Pencurian Berbasis Mikrokontroller Melalui Komunikasi Bluetooth

The negligence of residents and the lack of a house security system are the causes of the rampant cases of theft. Technological developments are increasingly rapid, making technology can be applied as a security system at home. This can be a solution to these problems. In this study a home security system was developed in the form of a prototype. This study uses a microcontroller that can be controlled using mobile devices via bluetooth communication. The prototype consists of a keypad to enter a password as a substitute for a home key, a PIR sensor as a detection of human body heat movements, and a buzzer as an alarm. The results of this study are that the prototype has been realized where the servo motor has been able to open and lock by entering the correct password. Setting ON / OFF lighting, display information on the LCD, and ON / OFF PIR sensor from an Android mobile phone via Bluetooth communication are in accordance with the plan.

Formulation of human body heat transfer coefficient under various ambient temperature, air speed and direction based on experiments and CFD

The purpose of this study is to confirm the effects of ambient temperature, airspeed, and wind direction on the heat transfer between human body and surrounding environment. First, a thermal manikin (TM) with fixed surface temperature (33 °C) was placed in a climate chamber with ambient temperatures of 20 °C, 24 °C, and 28 °C, at airspeed of under 0.1 m/s to confirm the effect of ambient temperature on heat transfer coefficient. In order to confirm effects of airspeed and wind direction, the same TM was then put in a wind tunnel with airspeeds ranging from 0.25 m/s to 1.4 m/s. The TM was set to face upwind, downwind, and perpendicular to the wind. Computational fluid dynamics (CFD) analysis was performed with conditions matching those of the experiment by using a computational TM with the same shape as that used in the experiment. In addition, numerical simulation of upward airflow condition and downward airflow condition in the standing posture with airspeed levels of 0.05–1.4 m/s was carried out. Higher ambient temperatures led to a decrease in the convective heat transfer coefficient and an increase in the radiative heat transfer coefficient. For airflows in the horizontal direction, whole-body convective heat transfer coefficient was the largest when the TM was facing downwind. For airflows in the vertical direction, the whole-body convective heat transfer coefficient for downward airflow was larger at airspeeds of 0.05–0.3 m/s. In contrast, when airspeed exceeded 0.3 m/s, the results were opposite.

Temperature Regulation in Colored Infrared-Transparent Polyethylene Textiles

Summary Effectively regulating heat flow between the human body and its environment not only increases thermal comfort but also presents a novel and potentially cost-effective approach to reducing building energy consumption. Infrared property-engineered textiles have been shown to passively regulate radiative heat dissipation for effective cooling and warming of the human body. However, a lack of dyes that can tune the textile color without compromising the infrared properties remains a major impediment to textile commercialization. Here, we report a new strategy utilizing inorganic nanoparticles as a coloring component for scalable brightly colored, infrared-transparent textiles. The as-fabricated composite textiles not only show a high infrared transparency of ∼80% and a passive cooling effect of ∼1.6°C–1.8°C but also exhibit intense visible colors with good stability against washing. This facile coloration approach will promote the commercialization of radiative cooling textiles in temperature-regulating wearable applications for effective energy savings.

Experiments in Posthumanism: On Tactical Rhetorical Encounters between Drones and Human Body Heat

Abstract This essay examines a particular, and particularly fraught enactment of digital and material rhetoric: a tactical media intervention into the militarized drone program, to map a posthumanist reading of “tactics,” updating Michel de Certeau’s famous concept for the current global situation. To introduce what will be posthuman about the model of tactics presented, this essay reviews the current state of work in rhetoric and composition on posthumanism and rhetorical materiality, arguing that it points us to a materiality that is not reducibly, simply present. This situation, on the one hand, produces a political need for experimentation, and yet if we encourage an experimental, tactical response to complex posthuman encounters such as that with the drone’s thermal vision, then we are also encouraging an affirmation of that encounter, which entails its own risks. This essay then argues that while Certeau gives us the tools to imagine how we can tactically use the things of the world, we need to reimagine tactics in a posthumanist key. This essay calls for a retooled model of tactics that would draw out the experimental possibilities of media tactics through understanding their imbrication in systems that are material, distributed, and yet not simply self-present things.