Search Results (32)

Yellow perch (Perca flavescens), a native species of the Great Lakes, has experienced a significant decline in wild harvest since the 1990s, leading to an increased reliance on aquaculture. This study aimed to optimize feeding rate for yellow perch by evaluating the effects of various feeding rates (1.5%, 3.0%, 4.5%, 6.0%, and 7.5% body weight (BW)/day) on growth, nutrient retention, and heat shock protein 70 expression in perch fingerlings (initial BW: 1.73 ± 0.11 g) over a four-week period. Following the feeding trial, an acute heat shock was induced by raising the water temperature from 23 °C to 31 °C, followed by an 18 h recovery period. Results indicated that both growth rate and whole fish lipid content increased with higher feeding rates (p < 0.05), while nutrient retention decreased. Growth and energy retention did not significantly improve beyond 4.5%, with maximum energy retention observed at 3.9% BW/day. Heat shock protein 70 expression was highest in liver tissue at a feeding rate of 6.2% BW/day, indicating that higher feeding levels may enhance thermal stress response. These results indicate that a feeding rate of 4.5% BW/day supports optimal growth, while 6.2% BW/day may be necessary to improve heat shock tolerance. The study provides practical insights for refining feeding strategies in yellow perch aquaculture. Full article

Battery power is crucial for wearable devices as it ensures continuous operation, which is critical for real-time health monitoring and emergency alerts. One solution for long-lasting monitoring is energy harvesting systems. Ensuring a consistent energy supply from variable sources for reliable device performance is a major challenge. Additionally, integrating energy harvesting components without compromising the wearability, comfort, and esthetic design of healthcare devices presents a significant bottleneck. Here, we show that with a meticulous design using small and highly efficient photovoltaic (PV) panels, compact thermoelectric (TEG) modules, and two ultra-low-power BQ25504 DC-DC boost converters, the battery life can increase from 9.31 h to over 18 h. The parallel connection of boost converters at two points of the output allows both energy sources to individually achieve maximum power point tracking (MPPT) during battery charging. We found that under specific conditions such as facing the sun for more than two hours, the device became self-powered. Our results demonstrate the long-term and stable performance of the sensor node with an efficiency of 96%. Given the high-power density of solar cells outdoors, a combination of PV and TEG energy can harvest energy quickly and sufficiently from sunlight and body heat. The small form factor of the harvesting system and the environmental conditions of particular occupations such as the oil and gas industry make it suitable for health monitoring wearables worn on the head, face, or wrist region, targeting outdoor workers. Full article

Textile-based thermoelectric (TE) devices are being investigated to power smart textiles autonomously. While previous research has focused on a solid system where the required junctions are fabricated into the device, there has been limited attention given to replacing these TE systems reliably. This work looks at a newer approach to the construction and demonstration of a wearable thermoelectric structure that employs three-dimensional knitted spacers to increase the temperature difference where the TE junctions are detachable and disposable. This system features positive and negative junctions which can be removed while maintaining its excellent voltage generation in low ΔT and good Seebeck coefficients. A mathematical model simulates the potential energy outputs and maximum power points generated, which can be used to increase the device’s performance for future wearable sensing applications. Full article

Textiles are often used to protect people from cold environments. While most garments are designed for temperatures not far below 0 °C, very cold regions on the earth near the poles or on mountains necessitate special clothing. The same is true for homeless people who have few possibilities to warm up or workers in cooling chambers and other cold environments. Passive insulating clothing, however, can only retain body heat. Active heating, on the other hand, necessitates energy, e.g., by batteries, which are usually relatively heavy and have to be recharged regularly. This review gives an overview of energy-self-sufficient textile solutions for cold environments, including energy harvesting by textile-based or textile-integrated solar cells; piezoelectric sensors in shoes and other possibilities; energy storage in supercapacitors or batteries; and heating by electric energy or phase-change materials. Full article

Effective low-grade waste heat harvesting and its conversion into electric energy by the means of thermoelectrochemical cells (TECs) are a strong theme in the field of renewable energy investigation. Despite considerable scientific research, TECs have not yet been practically applied due to the high cost of electrode materials and low effectiveness levels. A large hypothetical Seebeck coefficient allow the harvest of the low-grade waste heat and, particularly, to use TECs for collecting human body heat. This paper demonstrates the investigation of estimated hypothetical Seebeck coefficient dependency on KOH electrolyte concentration for TECs with hollow nanostructured Ni/NiO microsphere electrodes. It proposes a thermoelectrochemical cell with power density of 1.72 W·m⁻² and describes the chemistry of electrodes and near-electrode space. Also, the paper demonstrates a decrease in charge transfer resistance from 3.5 to 0.52 Ω and a decrease in capacitive behavior with increasing electrolyte concentration due to diffusion effects. Full article

As global warming increases day/night temperatures as well as frequencies of heat waves, studying physiological responses in long-term heat stress is required for sustainable yield production in the future. In this study, effects of long-term heat stress on photosynthetic, morphological, and yield parameters of three cherry tomato accessions, HR17, HR22, and HR24, were evaluated. The experiment was conducted under two temperature greenhouse conditions, where temperature set-point for ventilation was 30 °C and 35 °C during the day for 57 days, respectively. Plants were harvested on the 35th days and 57th days after heat treatments, and their physiological and morphological characteristics and yield traits were measured. Under control conditions, HR17 and HR22 had 0.5–0.6 harvest index, while HR24 had 0.3 harvest index. On 35th days after heat treatment, although yield loss percentage of HR17 was high (43%), it produced the highest fruit yield among all three accessions. However, after longer heat treatment, HR24 produced the highest fruit yields among all accessions with the smallest yield loss (34%). Furthermore, yield loss was highly associated with reductions in nitrogen use efficiency and water content in plant body under heat stress. The results of this study will provide breeders with a new insight into selecting heat-tolerant genotypes in cherry tomatoes. Full article

This paper aims to present new trends in energy-harvesting solutions pertaining to wearable sensors and powering Body Area Network nodes. To begin, we will present the capability of human beings to generate energy. We then examine solutions for converting kinetic and thermal energy from the human body. As part of our review of kinetic converters, we survey the structures and performance of electromagnetic, piezoelectric, and triboelectric systems. Afterward, we discuss thermal energy converters that utilize the heat generated by humans. In the final section, we present systems for converting energy from the electromagnetic waves surrounding a person. A number of these systems are suitable for use as wearables, such as RF harvesters and micro photovoltaic cells. Full article

The exigency of humans is boosting the necessity of Smart Textiles in this modern era. A decade ago, envisioning sophisticated outerwear with several uses were considered a challenge. This study aims to a jacket with 15 features; divided into 7 groups, including defense, sports, health, medical, women, and children safety mechanisms, 4 out of these 15 functions can be controlled by an Android app, “Smart Jacket BUFT”. To avoid nonrenewable energy sources, solar power and energy harvesting technology to produce electricity from body heat and foot-powered energy were used, Smart jacket has embedded circuits and sensors alone with AD8232, MAX30100, NEO6m GPS, and ESP32 microcontrollers & voice and app-control. It is hopping that; his initial stage of growth and improvement will pave the way for subsequent activities. Full article

Indoor and outdoor air pollution are associated with particulate matter concentration of minute size that deeply penetrates the human body and leads to significant problems. These particles led to serious health problems and an increased spread of infection through airborne transmission, especially during the COVID-19 pandemic. Considering the role of particulate matter during the spread of COVID-19, this paper presents a smart wireless sensor node for measuring and monitoring particulate matter concentrations indoors. Data for these concentrations were obtained and used as a risk indicator for airborne COVID-19 transmission. The sensor node was designed to consider air quality monitoring device requirements for indoor applications, such as real-time, continuous, reliable, remote, compact-sized, low-cost, low-power, and accessible. Total energy consumption of the node during measurement and monitoring of particulate matter concentration was minimized using a low-power algorithm and a cloud storage system embedded during software development. Therefore, the sensor node consumed low energy for one cycle of the particulate matter measurement process. This low-power strategy was implemented as a preliminary design for the autonomous sensor node that enables it to integrate with an energy harvester element to harvest energy from ambient (light, heat, airflow) and store energy in the supercapacitor, which extends the sensor node life. Furthermore, the measurement data can be accessed using the Internet of Things and visualized graphically and numerically on a graphical user interface. The test and measurement results showed that the developed sensor node had very small measurement error, which was promising and appropriate for indoor particulate matter concentration measurement and monitoring, while data results were utilized as strategic tools to minimize the risk of airborne COVID-19 transmission. Full article

Thermo-electrochemical cells (also known as thermocells, TECs) represent a promising technology for harvesting and exploiting low-grade waste heat (<100–150 °C) ubiquitous in the modern environment. Based on temperature-dependent redox reactions and ion diffusion, emerging liquid-state thermocells convert waste heat energy into electrical energy, generating power at low costs, with minimal material consumption and negligible carbon footprint. Recent developments in thermocell performances are reviewed in this article with specific focus on new redox couples, electrolyte optimisation towards enhancing power output and operating temperature regime and the use of carbon and other nanomaterials for producing electrodes with high surface area for increasing current density and device performance. The highest values of output power and cell potentials have been achieved for the redox ferri/ferrocyanide system and Co^2+/3+, with great opportunities for further development in both aqueous and non-aqueous solvents. New thermoelectric applications in the field include wearable and portable electronic devices in the health and performance-monitoring sectors; using body heat as a continuous energy source, thermoelectrics are being employed for long-term, continuous powering of these devices. Energy storage in the form of micro supercapacitors and in lithium ion batteries is another emerging application. Current thermocells still face challenges of low power density, conversion efficiency and stability issues. For waste-heat conversion (WHC) to partially replace fossil fuels as an alternative energy source, power generation needs to be commercially viable and cost-effective. Achieving greater power density and operations at higher temperatures will require extensive research and significant developments in the field. Full article

Recently, self-powered health monitoring systems using a wearable thermoelectric generator (WTEG) have been rapidly developed since no battery is needed for continuous signal monitoring, and there is no need to worry about battery leakage. However, the existing materials and devices have limitations in rigid form factors and small-scale manufacturing. Moreover, the conventional bulky WTEG is not compatible with soft and deformable tissues, including human skins or internal organs. These limitations restrict the WTEG from stabilizing the thermoelectric gradient that is necessary to harvest the maximum body heat and generate valuable electrical energy. This paper summarizes recent advances in soft, flexible materials and device designs to overcome the existing challenges. Specifically, we discuss various organic and inorganic thermoelectric materials with their properties for manufacturing flexible devices. In addition, this review discusses energy budgets required for effective integration of WTEGs with wearable biomedical systems, which is the main contribution of this article compared to previous articles. Lastly, the key challenges of the existing WTEGs are discussed, followed by describing future perspectives for self-powered health monitoring systems. Full article

It is a key challenge to continuously power personal wearable health monitoring systems. This paper reports a novel liquid metal-enhanced wearable thermoelectric generator (LM-WTEG that directly converts body heat into electricity for powering the wearable sensor system. The gallium-based liquid metal alloys with room-temperature melting point (24~30 °C) and high latent heat density (about 500 MJ/m³) are used to design a new flexible finned heat sink, which not only absorbs the heat through the solid-liquid phase change of the LM and enhances the heat release to the ambient air due to its high thermal conduction. The LM finned is integrated with WTEG to present high biaxial flexibility, which could be tightly in contact with the skin. The LM-WTEG could achieve a super high output power density of 275 μW/cm² for the simulated heat source (37 °C) with the natural convective heat transfer condition. The energy management unit, the multi-parameter sensors (including temperature, humidity, and accelerometer), and Bluetooth module with a total energy consumption of about 65 μW are designed, which are fully powered from LM-WTEG through harvesting body heat. Full article

The prosperity of intelligent wearables brings an increasingly critical problem of power supply. Regular rechargeable lithium or disposable button batteries have some problems, such as limited capacity, frequent replacement, environmental pollution, etc. Wearable energy harvester (WEH) can fundamentally solve these problems. Among WEHs, thermoelectric generator (TEG) is a promising option due to its independence of light condition or the motion of the wearer, and thermoelectric conversion (TEC) has the characteristics of quietness and continuity. Therefore, TEG has become a suitable choice for harvesting low-grade heat energy such as human body heat. Ionic thermoelectric gel (iTEG) has the advantages of a large Seebeck coefficient, freely defined shape and size, low processing cost, wide material sources, easy encapsulation, etc. In this paper, the gelatin-based iTEG is regulated and optimized by silica nanoparticles (SiO₂ NPs). The optimal compound quantity of SiO₂ NPs is determined, and the optimization mechanism is discussed through a series of characterization tests. Based on the iTEG, a kind of scalable flexible TEGs is proposed, and its preparation method is described in detail. A small wristband TEG (STEG) was made, and its Seebeck coefficient is 74.5 mV/K. Its bendability and stretchability were verified, and the impedance matching experiment was carried out. By charging a capacitor, the STEG successfully lights up an LED at a temperature difference (ΔT) of ~15.5 K. Subsequently, a large extended oversleeve TEG (LTEG) was prepared, and a set of heat sinks was added at the cooling end of the LTEG. Being worn on a volunteer’s forearm, the LTEG output a voltage of more than 3 V at ~20 °C. Through storing the converted energy in a capacitor, the LTEG directly drove a calculator without a DC–DC booster. The proposed iTEG and TEGs in this paper have the prospect of mass production, extending to people’s clothes, harvesting human body heat and directly powering wearable electronics. Full article

Wearable devices represent a versatile technology in the IoT paradigm, enabling non-invasive and accurate data collection directly from the human body. This paper describes the development of a smart shirt to monitor working conditions in particularly dangerous workplaces. The wearable device integrates a wide set of sensors to locally acquire the user’s vital signs (e.g., heart rate, blood oxygenation, and temperature) and environmental parameters (e.g., the concentration of dangerous gas species and oxygen level). Electrochemical gas-monitoring modules were designed and integrated into the garment for acquiring the concentrations of CO, O₂, CH₂O, and H₂S. The acquired data are wirelessly sent to a cloud platform (IBM Cloud), where they are displayed, processed, and stored. A mobile application was deployed to gather data from the wearable devices and forward them toward the cloud application, enabling the system to operate in areas where a WiFi hotspot is not available. Additionally, the smart shirt comprises a multisource harvesting section to scavenge energy from light, body heat, and limb movements. Indeed, the wearable device integrates several harvesters (thin-film solar panels, thermoelectric generators (TEGs), and piezoelectric transducers), a low-power conditioning section, and a 380 mAh LiPo battery to accumulate the recovered charge. Field tests indicated that the harvesting section could provide up to 216 mW mean power, fully covering the power requirements ($\overline{P}$ = 1.86 mW) of the sensing, processing, and communication sections in all considered conditions (3.54 mW in the worst-case scenario). However, the 380 mAh LiPo battery guarantees about a 16-day lifetime in the complete absence of energy contributions from the harvesting section. Full article

Farmers are often exposed to risk factors for musculoskeletal disorders through lifting, carrying heavy loads, and sustained or repeated full-body bending. Several relevant studies on ergonomic interventions have been conducted for specific agricultural tasks, such as harvesting and pruning, by experts without involving farmers. This study introduces ergonomic interventions to mitigate risk factors in a farming organization that cultivates peaches as the main crop based on ergonomic analysis of the entire peach farming cycle; subjective and objective evaluations of the proposed interventions are also performed. The ergonomic analysis and interventions were established based on consultations provided by an ergonomist, the government, and the organization members. Engineering controls were introduced for powered carts, sorters, and stools to reduce load carrying and awkward postures; moreover, thermal or cooling vests, winter shoes and gloves, and farmer hats were provided to alleviate cold or heat stresses. Administrative controls such as education/training and adjusting work–rest cycles were also recommended after considering the characteristics of the risk factors identified. The scores of the questionnaire survey from the organization members were high (>4.1 out of 5 for five questions), and postural loads for unstable postures by RULA were significantly reduced so as to avoid fast or immediate changes for the postures or working methods assessed. The study results are expected to help promote farmers’ health and enhance farming efficiency. Full article