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Additive manufacturing (AM) offers substantial flexibility in shape, but much less flexibility in materials and functionality – particularly at small size scales. A system for automatically incorporating microscale components would enable the fabrication of objects with more functionality. The purpose of this paper is to consider the potential of self‐assembly to serve as an automated programmable integration method. In particular, it addresses the ability of random self‐assembly processes to successfully assemble objects with high performance despite the possibility of assembly errors.

A self‐assembled thermoelectric system is taken as a sample system. The performance expectations for these systems are then predicted using modified one‐dimensional models that incorporate the effects of random errors. Monte‐Carlo simulation is used to predict the likely performance of self‐assembled thermoelectric systems and evaluate the impact of key process and system design parameters.

While assembly yield can drop quickly with increasing numbers of assembled parts, large functional assemblies can be constructed by arranging components in parallel to provide redundancy. In some cases, the performance losses are minimal. Alternatively, sensing can be incorporated to identify perfect assemblies. For small assemblies, the probability of perfection may be high enough to achieve an acceptable assembly rate. Small assemblies could then be combined into larger functional systems.

The paper identifies two strategies that can guide the development of AM processes that incorporate miniature components to increase the system functionality. The analysis shows that this may be possible despite significant errors in the self‐assembly process because systems may be tolerant of significant assembly errors.

This paper aims to concentrate on recent innovations in flexible wearable sensor technology tailored for monitoring vital signals within the contexts of wearable sensors and systems developed specifically for monitoring health and fitness metrics.

In recent decades, wearable sensors for monitoring vital signals in sports and health have advanced greatly. Vital signals include electrocardiogram, electroencephalogram, electromyography, inertial data, body motions, cardiac rate and bodily fluids like blood and sweating, making them a good choice for sensing devices.

This report reviewed reputable journal articles on wearable sensors for vital signal monitoring, focusing on multimode and integrated multi-dimensional capabilities like structure, accuracy and nature of the devices, which may offer a more versatile and comprehensive solution.

The paper provides essential information on the present obstacles and challenges in this domain and provide a glimpse into the future directions of wearable sensors for the detection of these crucial signals. Importantly, it is evident that the integration of modern fabricating techniques, stretchable electronic devices, the Internet of Things and the application of artificial intelligence algorithms has significantly improved the capacity to efficiently monitor and leverage these signals for human health monitoring, including disease prediction.

For using wireless sensors to monitor spindle units without opening the spindle shell to replace the battery, harvesting the waste heat from spindle units of machine tools for thermoelectric generation to drive wireless sensors is studied in this paper. The paper aims to discuss these issues.

In this paper, the thermal network method and the analogies between electrical and thermal domains are used in the simulation of power output performance of thermoelectric generation on a rotating spindle. After that, experiments are done to obtain the real power output performance of the generation and evaluate the feasibility to drive wireless sensors.

The paper provides that the output voltage of the thermoelectric generations was nearly linear with the rotating speed of the spindle, the output voltage was sensitive to the fixed position of the generations, and the thermoelectric system could drive the wireless sensor well most of the time during continuous operation of the spindle.

It is found that the thermoelectric generation could not provide enough power in the early start-up stage of the spindle rotation, so a high-efficiency power manage system, which will be studied in the future research, is needed to handle this problem.

The paper includes implications for the development of self-powered wireless sensors in the spindle unit for machine tool monitoring.

The paper develops a model of the power output performance of thermoelectric generation on a rotating spindle and tests the feasibility to drive wireless sensors with this power.

The purpose of this paper is to study using thermoelectric module to harvest the waste heat from spindle units of machine tools and drive wireless sensors stable, thermal structure design and optimization of the thermoelectric module.

In this paper, mesh-free-based method, rather than the standard finite element method, is used to analyze the thermal behavior of the thermoelectric modules with different structure. After that, experiments are done to obtain the real power output performance of those modules and evaluate the performance of driving a wireless sensor with those modules.

The paper provides that the difference in geometry structure can cause apparent change in surface temperature of heat-conducting plate, and the optimized thermoelectric module could increase the output voltage by about 7 per cent compared with the one without optimization.

It is found that the structure changing of the thermoelectric module is not the only way to increase the harvesting power, so a high efficiency power manage system is needed to be studied in the future.

The paper includes implications for the development of self-powered wireless sensors in the spindle unit for machine tool monitoring.

The paper develops models of thermoelectric modules with different structures on a rotating spindle, and tests the performance of driving wireless sensors with those thermoelectric modules.

A major potential application of the Peltier effect is the thermostating of electronic equipment, modules and individual components. Limitations of size and weight rule out mechanical refrigeration for small cooling units. However, Peltier cooling devices are size‐independent in their efficiency and in miniaturized form may be. incorporated into heat‐generating circuit components. Peltier units can remove heat directly from the source rather than from an external surface, and in addition, these thermodynamically reversible devices permit both heating and cooling. Electronics may thus be thermostated at or below ambient temperature to provide increased reliability and stability. The authors discuss specific applications of Peltier thermostating under development.

The purpose of this paper is to experimentally and numerically investigate the cooling performance of the air-to-water thermoelectric cooling system under different working conditions.

An air-to-water thermoelectric cooling system was designed and manufactured according to the principle of discrete binary thermoelectric Peltier modules, and the thermal performance, heat transfer rate and average COP values were examined at different cooling water temperatures and voltages applied. Additionally, numerical simulations were performed by computational fluid dynamics approach to investigate the temperature distribution and airflow structure inside the cooling chamber.

Analyses were performed using experimental tests and numerical methods. It was concluded that, by decreasing the cooling water temperature from 20 to 5 °C, the average COP increases about 36%. The voltage analysis showed that the efficiency of the system does not always increase as the voltage rises; more importantly, the optimum voltage is different and depends on whether it is desired to increase COP or increase the cooling rate.

In the studies published in the field of thermoelectric cooling systems, little attention has been paid to the voltage applied and its relationship to other operating conditions. In most cases, the tests are performed at a constant voltage. In this study, several options, including applied voltage and cooling water temperature, were considered simultaneously and their effects on performance have been tested. It was found that under such studies, optimization work should be done to evaluate maximum performance in different working conditions.

This paper aims to present an experimental investigation and optimization of a low-temperature thermoelectric module to examine the influence of the main operating conditions.

In this work, a comparison was made by varying the various operating parameters such as heat source temperature, the flow rate of the cold fluid and the external load resistance. A Taguchi method was applied to optimize the parameters of the system. Three factors, including the external load resistance, mass flow rate of water (at the heat sink side) and heater temperature (at the heat source side) along with different levels were taken into account. Analysis of variance was used to determine the significance and percentage contribution of each parameter.

The experimental results show that the maximum power output 8.22W and the maximum conversion efficiency 1.11 per cent were obtained at the heater temperature of 240°C, the cold fluid mass flow rate of 0.017 kg/s, module temperature difference of 45°C and the load resistance of 5 O. It was observed that the optimum parameter levels for maximum power output determined as 5 O external load resistance, 0.17 kg/s mass flow rate of water and 240°C heater temperature (A1B3C3). It reflects that these parameters influence on the optimum conditions. The heater temperature is the most significant parameter on the power output of the thermoelectric module.

It is clear from the confirmation test that experimental values and the predicted values are in good agreement.

Three types of PbTe samples, e.g. nanoparticles, nanowires and bulk ingots, have been prepared. The investigation of the Seebeck coefficient of PbTe nanoparticles and nanowires clearly shows the sign change in the temperature range of 575~650 K, which is not observed for bulk ingots. Unfortunately, this temperature range is within the proposed operation temperature range for thermoelectric devices using PbTe and hence, such a change will affect their proper performance. The observed sign change of Seebeck coefficient is not simply caused by the composition variation at high temperature. It is mainly attributed to the extrinsic-to-intrinsic-semiconductor transition for PbTe nanocrystals due to the competing factors between quantum size effect increasing band gap and self-purification process decreasing their charge carrier concentration, which shift the transition point of nanocrystals to lower range as compare to that of bulk samples. Thus, such phenomenon should be considered carefully in the design of thermoelectric devices using semiconductor nanocrystals, which have attracted much attention recently.

Possible application of mixed (thick/thin film) thermopiles to supply autonomous microsystems.

PdAg/AG or PdAg/TSG thermocouples were deposited onto a circular alumina or LTCC substrates. Their thermoelectric power, resistance as well as output electrical power were characterized vs temperature gradient and chosen parameters of thermopile fabrication process.

Semiconductors have high Seebeck coefficient, so investigated kind of thermopile has high output electrical power E_T. It achieves 50 mV per single junction for temperature difference of about 200°C.

The problem is very high resistivity of germanium alloys, even after burn‐in process. Therefore output electrical power P is seriously reduced. To improve thermocouples properties, optimization process is required. For example, thin film layers quality can be improved, semiconductive arms width can be increased or shorter arms can be used.

Application of mixed thick/thin film technology for fabrication of miniaturized thermoelectric generators.