Peltier Element Research Articles

A thermoresponsive valve to control fluid flow in microfluidic paper-based devices

Microfluidic paper-based analytical devices (μPADs) have recently attracted the attention of researchers and industry owing to their various advantages. However, µPADs lack a way to control fluid flow; therefore, it is difficult to perform complex immunoassays that use multiple reagents and replace the reagents from the analytical area. We developed a controllable thermoresponsive valve for μPADs by functionalizing a polyvinylidene difluoride porous membrane with plasma-induced graft polymerization of poly(N-isopropylacrylamide) (PNIPAAm), which is a thermoresponsive polymer that changes its hydrophilic properties near the lower critical solution temperature (LCST; 32 °C). Surface analysis by attenuated total reflectance Fourier transform infrared spectroscopy confirmed that the fabricated thermoresponsive valves coated with PNIPAAm. The valve performance was evaluated by sandwiching the thermoresponsive valve between two paper microchannels stacked in a T-shaped paper microfluidic device. The thermoresponsive valve fabricated with a monomer concentration ranging from 2.3 to 3.0 wt% and a polymerization time of 5 h or 2.0 wt% and 20–22 h showed good valve performances. These valves were able to stop the flow at room temperature, and allow the flow by opening within 20 s after heating was initiated using a Peltier element located just under the valve. The valve was successfully closed, thereby stopping the flow, and opened by heating. Although a detailed evaluation of the fluid behavior is necessary, we have demonstrated that our thermoresponsive valve can be opened and closed reversibly by temperature control. We believe that this thermoresponsive valve could potentially be used to control the flow of multiple reagents in µPADs.

Substantiation of Rational Parameters of the Dehumidifier of the Air Flow of an Energy-saving Drying Plant

A technique for studying the rational modes of operation of Peltier elements is presented. Specific recommendations are given for bringing the moisture content of biologically active bee products to the requirements of GOST by means of a special dehumidifier made on the basis of Peltier elements in the process of drying with hot air.

Cooling Crystallization with Complex Temperature Profiles on a Quasi-Continuous and Modular Plant

Volatile markets and increasing demands for quality and fast availability of specialty chemical products have motivated the rise of small-scale, integrated, and modular continuous processing plants. As a significant unit operation used for product isolation and purification, cooling crystallization is part of this trend. Here, the small-scale and integrated quasi-continuous filter belt crystallizer (QCFBC) combines cooling crystallization, solid-liquid separation, and drying on a single apparatus. This contribution shows the general working principle, different operation modes, and possibilities of temperature control with the modular setup. For precise temperature control in cooling crystallization, Peltier elements show promising results in a systematic study of different operation parameters. Sucrose/water was used as a model substance system. The results confirm that seed crystal properties are the most important parameter in crystallization processes. Additionally, an oscillating temperature profile has a narrowing effect on the crystal size distribution (CSD). The integrated, small-scale, and modular setup of the QCFBC offers high degrees of flexibility, process control, and adaptability to cope with future market demands.

Improving a tempering machine for confectionery masses

This paper reports the improved model of a tempering machine for heating the formulation mixture of marshmallow, characterized by heat supply to the working tank through the replacement of a steam jacket with heating by a film resistive electric heater of radiative type (FREhRT). The surface of the heat exchange of the device was increased by heating the stirrer with FREhRT; secondary energy (30....85 °C) was used by converting it by Peltier elements for the autonomous operation of superchargers for cooling the engine compartment. The proposed solution will lead to an increase in the efficiency of the device, which is explained by a decrease in its specific metal consumption through the use of FREhRT. A reduction in the duration of heating (75 °C) a marshmallow formulation mixture was experimentally established: in the examined model, 530 s, compared with the analog, 645 s. That confirmed the reduction in heating time to the set temperature by 21.7 % compared to the MT-250 basic design. The calculations have established a decrease, by 13 %, in the specific energy consumption for heating the volume of a unit of product when using the improved structure, 205.7 kJ/kg, when using the basic one ‒ 232.1 kJ/kg. The increase in the efficiency of the proposed structure is explained by a decrease in the specific metal consumption of the device from 474 kg/m2 in the base apparatus to 273 kg/m2 in the improved one. The study results confirm the increase in the resource efficiency of the improved tempering machine, which is achieved by eliminating the steam jacket; increasing the heat exchange surface by heating the stirrer. The heat transfer by FREhRT simplifies the operational performance of the temperature stabilization system in a working tank. The reported results could prove useful when designing thermal devices with electric heat supply under the conditions of using secondary energy, which is relevant for ensuring resource efficiency

MODERNIZATION OF EQUIPMENT FOR PRODUCTION OF CHEESE PRODUCT

The article substantiates the modernization of the apparatus for melting cheese masses, which differs in the method of heat supply of working tanks by replacing the steam jacket for heating with a flexible film resistive electric heater of the radiating type (GPREnVT). The heat transfer surface of the working tank is increased in the apparatus due to the heating of the mixing device. The advanced installation is characterized by the use of secondary thermal energy of melting of cheese masses (35… 95°C) by converting its Peltier elements into low-voltage supply voltage of autonomous fans (3.5…12 W) to cool the control unit. This will increase the efficiency of the proposed design, due to the reduction of dimensional and weight parameters of the apparatus for melting cheese masses by replacing the steam method of heating with electric. The reduction of the duration of the equipment output to the stationary mode (85 ° С) during melting of cheese masses was experimentally confirmed: for the bowl of the research apparatus - 575 s, in comparison with the analogue – 725 s. This scientific work confirms the reduction of the duration of entering the stationary mode by 2% compared to the basic device B6-OPE-400. It is proved that the main indicator of resource efficiency of specific energy consumption for heating the volume of a unit of product has decreased 1.2 times. In the modernized apparatus for melting cheese masses, it is equal to 3037,2 kJ/kg, and the indicator of the basic version B6-OPE-400 – 3672.5 kJ/kg. According to the obtained results, there is an increase in resource efficiency, which is achieved by: elimination of steam heating networks; increasing the heat transfer surface of the working bowls by heating the stirrer with a flexible film resistive electric heater of the radiating type. Heat dissipation of the heater improves the performance of the temperature stabilization system in the bowl of the cheese melter. The obtained results can be used in the design of thermal equipment with electric heating in the use of secondary thermal energy.

Analysis of Thermal and Roughness Effects on the Turbulent Characteristics of Experimentally Simulated Boundary Layers in a Wind Tunnel.

The aim of this paper is to analyse the thermal effects in a wind tunnel experiment to simulate the planetary boundary layer (PBL). Experiments were performed in the wind tunnel of the Laboratory of Constructions Aerodynamics at the Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul State, Brazil. This wind tunnel is a closed return low-speed wind tunnel specifically designed for dynamic and static studies on civil construction models. As a novelty, one of the experimental sections of the wind tunnel was equipped with a metal sheet with Peltier elements coupled to it. In other words, thermal effects generating new flow patterns become feasible and open pathways to compare wind tunnel simulations to those in the PBL. Furthermore, measurements obtained with the smooth floor of the wind tunnel were repeated under the same conditions with the addition of the roughness in the floor, and the mechanical turbulence generated by the surface roughness significantly amplified the exchange of momentum and heat between the regions located in vertical direction of the wind tunnel boundary layer. In the presence of turbulent heat flux near the surface, thermal effects contribute to the increase of the turbulence intensity. Turbulent energy spectra for flow velocities and different heights were obtained using the Hilbert–Huang transform method, and the observed convective turbulence energy spectra behavior reproduced those measured in an unstable surface PBL.

Pemanfaatan Termoelektrik Sebagai Sumber Energi Terbarukan

Abstract - Research has been carried out on power generators using thermoelectric or Peltier elements, with the aim of knowing how much output or output voltage the module produces by varying the temperature entered into the Peltier module. Peltier element is a material that can convert a certain temperature difference into electrical energy using the principle of the Seebeck effect. In this research, a thermoelectric generator module is designed using a Peltier element type SP184827145SA. This study aims to determine the characteristics of the power generated by the thermoelectric generator module with a series of Peltier elements with a given temperature variation, the voltage generated by the thermoelectric element is proportional to the temperature given on the high temperature side, the higher the temperature given, the greater the voltage. which are issued. From the research, it was found that when the Peltier heat temperature reaches 70ᵒc it can produce an output of 1.49v, while when the temperature gets lower the lower the voltage generated

Experiments on temperature regulation using a Peltier element and PID technique

An experiment on temperature regulation was prepared and is regularly conducted in a laboratory course on electronic at the faculty level. The experiment demonstrates the use, problems and solutions with feedback introduced for temperature regulation. The plans for hardware and complete software to run the experiment are freely available at author’s web page. The hardware consists of easily obtainable and cheap components. Temperatures are measured by widely used semiconductor thermometer chips DS18B20 and results are presented on a PC connected to the experiment. The experiment with heating and cooling can be implemented already at a secondary school level, but the theory behind the experiment requires better understanding of mathematics (differential equations) available at faculty level. The experiment is complemented with software simulation to be used in lectures.

D-depleted water isotopic measurement with a miniaturized cavity ring-down spectrometer aiming for exploration of lunar water

A miniaturized cavity ring-down spectrometer (mini-CRDS) with 5 cm cavity length using a near-infrared laser diode was developed, aiming for exploration of lunar water. This mini-CRDS enables us to measure a water vapor sample of limited amount at low pressure (< 100 Pa) by an unique mechanism using Peltier element modules that changes the resonance point to interpolate the gap of the free spectral range (FSR) of the cavity. We measured aqua samples with different D/H ratios and applied Voigt profile fitting to the absorption spectra, then obtained a calibration line of HDO isotope. The signal to noise ratio (SNR) of HDO peak at δD = − 980‰ was 7.17, which was enough higher than the detection limit of 3.

Behavior of Nymphs and Adults of the Black-Legged Tick Ixodes scapularis and the Lone Star Tick Ambylomma americanum in Response to Thermal Stimuli.

Simple SummaryTicks use heat emitted by warm-blooded animals to orient to potential hosts for blood-feeding. Here we study the behavior of two species, the black-legged tick and the lone star tick, to sources of heat emissions representative of a human host. First, we offered a heat source to females walking on a locomotion compensator (servosphere). While speed, walking distance, displacement and linearity were unaffected by the source of heat, walking trajectories of ticks were aimed toward this thermal source. In a double-choice walking bioassay, both nymphs and adults of both sexes of the lone star tick, but not the black-legged tick, oriented to a thermal source. From a practical standpoint, a source of heat might be used in combination with other, e.g., chemical or visual, signals in strategies aimed at the survey or control of targeted tick species.Ticks use chemical and thermal signals emitted by humans and other vertebrates to locate suitable hosts for a blood meal. Here, we study the behavior of black-legged Ixodes scapularis and the lone star ticks Amblyomma americanum exposed to heat sources held at temperatures near those of vertebrate hosts (32 °C). First, we used a locomotion compensator to test behavioral responses of ticks to an infrared light emitting diode (LED). The servosphere allowed us to measure parameters such as velocity, acceleration, linearity, and orientation. Then a heating element (Peltier) located in one of the extremes of a double-choice vertical rod (flying T), was employed to observe upward movement of the ticks toward such a heat source. While both species oriented toward the LED, only lone star ticks were attracted to the Peltier element while climbing upward. In conclusion, we showed that heat attracted ticks from short distances up to several centimeters on a the servosphere, and those responses differed between the two species of ticks on the flying T. We discuss our results in the context of the ecology of both tick species and their potential in tick survey and management.

Design of a dual electrochemical quartz crystal microbalance with dissipation monitoring

Abstract. The design and fabrication of a dual electrochemical quartz crystal microbalance sensor unit with dissipation monitoring (EQCMD) for in situ monitoring of crystallization processes, such as the formation of zeolites from liquid media, is reported. The integrated temperature unit is based on Peltier elements and precision temperature sensors with accurate and fast temperature control. In this design, two thickness-shear mode quartz disk resonators are oppositely arranged, enabling the application of an electric field through the sample while concurrently being able to monitor the resonance frequencies and quality factors of both resonators. As demonstrated experimentally, this allows for the characterization of the sample by means of the viscosity, via the acoustic impedance, and the electrical conductivity. Monitoring zeolite formation based on these parameters, however, turned out to be challenging, mainly because the electrodes suffered from severe corrosion. Despite the use of chemically resistant materials and insulating coatings, the electrodes were attacked by the reaction medium, presumably due to surface defects. Furthermore, air bubbles, which developed over time and adhered persistently to the quartz surfaces, also had a negative influence on the measurement. Despite the encountered issues, we want to communicate our sensor design, as its basic functionality, including the dedicated electronics and software perform well, and reporting the observed issues will enable further progress in this field.

Effects of alternating heat and cold stimulation using a wearable thermo-device on subjective and objective shoulder stiffness

BackgroundTechnological innovations have allowed the use of miniature apparatus that can easily control and program heat and cold stimulations using Peltier elements. The wearable thermo-device has a potential to be applied to conventional contrast bath therapy. This study aimed to examine the effects of alternating heat and cold stimulation (HC) using a wearable thermo-device on subjective and objective improvement of shoulder stiffness.MethodsTwenty healthy young male individuals (20.3 ± 0.6 years) participated in this study. The interventions were randomly conducted under four conditions, including HC, heat stimulation, cold stimulation, and no stimulation on their bilateral trapezius muscle, after a 30-min typing task. Each intervention was administered at least 1 week apart. The analyzed limb was the dominant arm. Muscle hardness was assessed using a portable muscle hardness meter, as well as the skin temperature over the stimulated area. After each condition, the participants were asked for feedback regarding subjective improvement in refreshed feelings, muscle stiffness, and muscle fatigue using an 11-point numerical rating scale.ResultsWith regard to muscle hardness, only the HC condition significantly decreased from 1.43 N to 1.37 N (d = 0.44, p < 0.05). Additionally, reduced muscle hardness in HC condition was associated with the degree of skin cooling during the intervention (cold max: r = 0.634, p < 0.01; cold change: r = −0.548, p < 0.05). Subjective improvement in refreshed feelings, muscle stiffness, and muscle fatigue was determined in the HC and heat stimulation conditions compared with the no stimulation condition (p < 0.01 and p < 0.05, respectively). Moreover, the HC condition showed significantly greater improvements in muscle stiffness and fatigue compared to the cold stimulation condition (p < 0.05).ConclusionsThe current study demonstrated that HC promoted not only better subjective symptoms, such as muscle stiffness and fatigue, but also lesser muscle hardness. Furthermore, an association was observed between the degree of skin temperature cooling and reduced muscle hardness during HC. Further investigations on the ratio and intensity of cooling should be conducted in the future to establish the optimal HC protocol for muscle stiffness or fatigue.Trial registrationUMIN000040620. Registered 1 June 2020

AUTONOMOUS POWER SUPPLY SYSTEM FOR SURFACE DISINFECTION BY INFRARED RADIATION IN PROTECTED GROUND

Reducing heat losses and utilization of secondary energy resources contribute to improving the energy efficiency of equipment, technologies and enterprises. The improvement of one of the processes in the technology of growing vegetables and berries, the use of thermal energy in the disinfection of surfaces in protected ground is the main idea of the developed autonomous power supply system of the installation. (Research purpose) The research purpose is developing a technological scheme of the power supply system of the installation for disinfection of surfaces with infrared radiation in protected ground. (Materials and methods) The article presents the scheme of an experimental installation for surface disinfection with infrared radiation, allowing to develop a technological scheme of the power supply system. The experimental setup is designed to study the distribution of the temperature field of infrared radiation on the surface (soil, substrate, concrete floor). (Results and discussion) During the operation of infrared radiators during disinfection of surfaces in protected ground running on liquefied gas, not all the thermal energy from gas combustion passes into infrared radiation; part of the thermal energy is lost to the environment due to convection and thermal conductivity. Losses can reach up to 50 percent. In order to reduce heat losses and reach the autonomy of the surface disinfection unit in protected ground, it was proposed to use thermal generators operating on the Seebeck - Peltier effect, the conversion of thermal energy into electrical energy for electricity generation. The Peltier elements are connected both sequentially and in parallel. The electricity received from the Peltier elements enters the battery, accumulates, and then is spent on the operation of the installation. (Conclusions) The technological scheme of power supply system of the surface disinfection plant being developed can be adapted and applied to other technological processes where there are heat losses to the environment.

Two-Dimensional numerical parametric modeling of the capillary microgripper cooling system with unsteady fluid flow

The paper presents a parametric analysis of a 2D model of a fluid cooling system for the hot side of a Peltier element of a capillary microgripper. An unsteady flow of coolant in the cooling chamber is considered. The cooling efficiency is studied for three chamber geometries with different radiator locations: monolithic, located on the Peltier element; with one or three ribs. Mathematical models are built: fluid flow through the microgripper chamber; heating the radiator with the hot side of the Peltier element; heat transfer from the radiator to fluid and the removal of the heated fluid from the chamber. The simulation is carried out in the FreeFem++ program until the average change in the temperature of the radiator over the period of fluid oscillations reaches saturation (microgripper operating mode). Using the method of orthogonal central compositional planning, analytical dependences of response functions (maximum temperature on the radiator, amplitude of temperature change on the radiator, and time to establish the operating mode) on model factors (average coolant velocity, heat transfer coefficient, frequency and amplitude of fluid velocity oscillations) are obtained. For each considered geometry and response function, leading and insignificant factors are determined. A parametric analysis of the influence of the physical parameters of the system on the operation of the cooling system was carried out. The simulation results show that the geometry that provides a high degree of cooling and a faster exit to the operating mode (radiator with three fins) has a large amplitude of temperature fluctuations on the radiator and can be used in technical devices that are less sensitive to temperature fluctuations on the radiator. The single fin radiator geometry provides the least radiator temperature fluctuation and can be used to cool capillary microgripper.

DISINFECTION OF SOIL AND SUBSTRATE BY INFRARED RADIATION WITH AN AUTONOMOUS POWER SUPPLY SYSTEM

Thermal energy occupies a special place in human life. In most cases, the waste heat is irretrievably lost. This lost resource is no longer worth anything, so its reuse will contribute to both reducing the energy crisis and protecting the environment. For this reason, new ways of converting thermal energy into electrical energy are more relevant today than ever. The use of electric energy and power supply of installations are important in the agro-industrial complex, especially the use of an autonomous power supply system for process automation. (Research purpose) The research purpose is to develop the devices for disinfection of soil and substrate by infrared radiation in protected soil with the utilization of heat from the infrared emitters using Peltier thermoelectric generators. (Materials and methods) The article presents the operation of the developed device. (Results and discussion) During the operation of the installation, the cases of the infrared emitters are heated to a temperature of 500 degrees Celsius, and this thermal energy is released into the atmosphere. To increase the energy efficiency of this installation, infrared radiators are covered with a sealed steam jacket from above, water is poured inside, is heating up, evaporates and settles on the dome, thereby transferring heat from the covers of infrared radiators to the dome. Peltier thermoelectric generators are installed on the dome, which are designed to convert thermal energy into electrical energy, Peltier elements are connected in series and in parallel. The electricity received from the Peltier elements enters the battery, accumulates and is spent on the operation of devices for automatic control of soil and substrate disinfection, which makes it possible for the installation to operate autonomously. (Conclusions) For the functioning of the device is used the utilization of heat losses from the operation of infrared emitters using Peltier thermoelectric generators.

Synthesis of new microfluidics models in the research in the “Robotics and Control in Technical Systems” laboratory

Robotics is an interdisciplinary scientific direction, therefore, when solving a number of problems, it becomes necessary to conduct research that is typical for other areas of science. So, when synthesizing new types of equipment in the „Robotics and Control in Technical Systems” laboratory, more accurate characteristics of individual components and assemblies were required, which ultimately led to a whole cycle of work on microfluidics. Of particular interest in the work performed is the development of new microdevices, since this involves the construction of a single complex of new mathematical and computer models that link hydrodynamics, elasticity theory, heat transfer process, parametric optimization and control theory. The first models were obtained that describe the movement of a piston fixed by an elastic spring in a pipe, taking into account the influence of dry viscous types of friction. By the method of factorial computational experiment, analytical dependencies were obtained for the main part of the fuel dosing unit — servo piston. Next, mathematical and computer models were built to analyze the fluid flow through a channel with variable geometry. Based on the simulation results, the design of a new micromechanical device — a piezoelectric micropump consisting of an elastic tube and annular piezoelements located on it, the sequential oscillation of which creates a non-zero average fluid flow, was refined. In the course of the adaptation of the model, an effective design of the device for smoothing fluid flow pulsations was obtained. These devices were developed and calculated for use in the liquid cooling system of capillary microgripper. A parametric analysis of the process of cooling the hot side of the Peltier element of the microgripper was carried out with a change in the following gripper parameters: the size and shape of the radiator, the coolant flow rate and the heat transfer coefficient. The results of the analysis of temperature fluctuations of the radiator under unsteady fluid flow confirmed the expected dependences of the cooling efficiency on the chosen geometry of the radiator and low-frequency fluid flow fluctuations.

Improving the unit for melting cheese masses

This paper reports the improved model of the unit for melting cheese masses. The device differs in the technique of heat supply to working tanks through the replacement of a steam jacket with heating by a flexible film resistive electric heater of radiative type (FFREhRT). The heat exchange surface of the working container was increased through heating the mixing device by FFREhRT. In addition, the unit is distinguished by utilizing secondary thermal energy of melting cheese masses (35...95 °C) by converting it with Peltier elements into a low-voltage power supply to autonomous fans (3.5...12 W) in order to cool the control unit. Such a solution would improve the efficiency of the proposed structure, which is explained by reducing the dimensional and weight parameters of the cheese melting unit by replacing the steam heating technique with an electric one. A decrease in the time to enter a stationary mode (85 °C) when melting cheese masses was experimentally confirmed: for the bowl of the examined unit ‒ 575 s, compared to the analog ‒ 725 s. That confirms the reduction in the time to enter a stationary mode by 21 % compared to the base unit B6-OPE-400. The estimation has established a 1.2-time decrease in the main indicator of resource efficiency of the specific energy consumption for heating the volume of a unit of product in the improved plant for melting cheese masses – 3,037.2 kJ/kg, compared to the base B6-OPE-400 – 3,672.5 kJ/kg. The results confirm an increase in resource efficiency that is achieved by the elimination of steam heat networks; the increased heat exchange surface of working bowls by heating the stirrer with the help of FFREhRT. The heat transfer that employs FFREhRT simplifies the operational indicators of the temperature stabilization system in the bowl of the cheese mass melting unit. The results reported here may prove useful when designing thermal equipment with electric heating while using secondary thermal energy.

ОТРИМАННЯ ЕЛЕКТРИЧНОЇ ЕНЕРГІЇ ВІД БАТАРЕЇ ОПАЛЕННЯ

As a result of the analysis of the research results, the volt-ampere characteristic of the Peltier element used in the mode of temperature difference generation and the dependence of the temperature difference on the "hot" and "cold" surfaces on the consumed electric power were obtained. It is determined that the efficiency of the element decreases with increasing power consumption, when when a significant temperature difference is reached, the element between the heated and cooled surfaces can not sufficiently perform the functions of thermal insulation. It has been experimentally determined that it is expedient to use Peltier elements in the temperature range when the difference is from 13 to 25 ° C, and this is possible in the presence of an effective mechanism of heat dissipation from the hot side. Thus, when developing devices with thermoelectric cooling, it is advisable to choose the optimal mode of operation with a voltage below the nominal. The work of the element was experimentally tested on the basis of EMF determination for one element of TPP 1– 12706. The experimental dependences of the plate and radiator temperature on the generated EMF for the Peltier element TPP 1 - 12706 were obtained. and quality of TE devices. The scientific novelty of the work is to confirm the possibility of creating a heat generator using as a source of energy available in everyday life temperature difference, in particular, the dependence of the generated EMF on the temperature difference between "hot" and "cold" side Peltier TPP 1 - 12706 The practical significance of the work lies in the possibility of using the device in domestic conditions when using a battery with heating to obtain electricity that can be used to connect a flashlight, humidifier device, charge the phone.

Microheater: material, design, fabrication, temperature control, and applications-a role in COVID-19.

Heating plays a vital role in science, engineering, mining, and space, where heating can be achieved via electrical, induction, infrared, or microwave radiation. For fast switching and continuous applications, hotplate or Peltier elements can be employed. However, due to bulkiness, they are ineffective for portable applications or operation at remote locations. Miniaturization of heaters reduces power consumption and bulkiness, enhances the thermal response, and integrates with several sensors or microfluidic chips. The microheater has a thickness of ~ 100 nm to ~ 100 μm and offers a temperature range up to 1900℃ with precise control. In recent years, due to the escalating demand for flexible electronics, thin-film microheaters have emerged as an imperative research area. This review provides an overview of recent advancements in microheater as well as analyses different microheater designs, materials, fabrication, and temperature control. In addition, the applications of microheaters in gas sensing, biological, and electrical and mechanical sectors are emphasized. Moreover, the maximum temperature, voltage, power consumption, response time, and heating rate of each microheater are tabulated. Finally, we addressed the specific key considerations for designing and fabricating a microheater as well as the importance of microheater integration in COVID-19 diagnostic kits. This review thereby provides general guidelines to researchers to integrate microheater in micro-electromechanical systems (MEMS), which may pave the way for developing rapid and large-scale SARS-CoV-2 diagnostic kits in resource-constrained clinical or home-based environments.Graphical abstract

Physical processes simulation in a precision device for liquid samples thermal cycling

An urgent task is the development of devices that provide a precision temperature change. The devices used in the real-time polymerase chain reaction method require not only repeated cyclic temperature changes with high accuracy, but also the temperature gradient minimization over the working fluid. In this article, the modeling of the working processes taking place in the thermal block of the device with the previously proposed thermohydraulic system, which ensures the temperature change together with the Peltier elements, is carried out. A mathematical model is formulated and a differential equation, boundary and initial conditions are substantiated. Numerical methods for solving the mathematical model in the Elcut software were applied. An experimental setup was developed and a study of heat exchange processes in the thermal block of a nucleic acid analyzer with a thermohydraulic system was carried out, confirming the adequacy of the developed mathematical model.