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Abstract Objectives To compare the performance of the TEG 5000 and TEG 6S Global Hemostasis cartridge. Methods We reviewed validation data of the TEG 5000 and TEG 6S Global Hemostasis cartridge. The specimens were analyzed in parallel according to the manufacturer’s operating instructions. Results Fifty-four healthy donors and 13 donors with known hemostatic abnormalities were included. The correlations between instrument types were only moderate—the Spearman rank correlations were 0.55, 0.62, 0.64, and 0.72, respectively, for CK R, K, angle, and maximum amplitude (MA) parameters. Using the manufacturer’s device-specific reference ranges to classify results as normal/abnormal, there was weak agreement in the qualitative interpretation of all parameters (Cohen’s κ for agreement for CK R, K, angle, and MA was 0.418, 0.154, –0.083, and 0.127, respectively). This could lead to discordant transfusion decisions. Conclusions These findings indicate that the TEG 5000 and TEG 6S may not be used interchangeably.

In this paper, the results of experimental studies of a prototype cryogenic thermoelectric generator (TEG) using transit heat flows in a liquefied natural gas (LNG) evaporator are considered. The main objective was to develop a TEG with low capital cost, integrated directly into an LNG vaporizer, capable of generating electricity at a reasonable levelized cost (LCOE). A demonstration prototype of TEG was created with a power output of 800 W. The prototype used liquid nitrogen (LN2) instead of LNG as the working fluid. Achieved technical parameters of TEG provide the LCOE decrease to a level of ≈ 0.015 $/kWh. Such results are achieved using standard components (thermoelectric modules, heat exchangers, etc.) thanks to the optimization of the TEG design.

The use of low-potential energy sources is an urgent problem of our time, as more than 70% of the energy used by mankind is lost in the form of low-potential waste. A promising technology of converting such thermal energy into electricity is the thermoelectric method. The scale of use of any technology depends on its efficiency. The problem of TEG efficiency can be divided into two separate tasks—the task of creating efficient thermoelectric materials, and the task of optimizing the parameters of thermoelectric devices. In real conditions the last task plays a significant, often crucial, role. Therefore, many works are devoted to their research. The fundamental basis for solving this problem is the mathematical modeling of the thermoelectric generator circuit, which includes a heat source, a thermoelectric converter, a cooling system, and a payload. In this paper the author presents some generalized results of previous research that can benefit the developers of thermoelectric devices. The first part of the article presents the basics of the methodology used. Next, I draw attention to the possibility of better tuning of the properties of thermoelectric materials to a specific task in case of considering external conditions. The final part of the paper provides an assessment of technical and economic indicators of TEG and formulates the conditions under which this technology can ensure competitiveness in the modern energy market.

Prediction of thermoelectric performance parameters by numerical methods is an inherent part of thermoelectric generator (TEG) development and allows for time- and cost-saving assessment of material combinations and variations of crucial design parameters (e.g., shape, pellet length, and thermal coupling). Considering the complexity of a TEG system and its numerous affecting factors, the clarity and the flexibility of a mathematical treatment comes to the fore. Comfortable tools are provided by commercial finite element modeling (FEM) software offering powerful geometry interfaces, mesh generators, solvers, and postprocessing options. We describe the level of development and the simulation results of a three dimensional (3D) TEG FEM. Using ANSYS 11.0, we implemented and simulated a TEG module geometry under various conditions. Comparative analytical one dimensional (1D) results and a direct comparison with inhouse-developed TEG simulation software show the consistency of results. Several pellet aspect ratios and contact property configurations (thermal/electrical interface resistance) were evaluated for their impact on the TEG performance as well as parasitic effects such as convection, radiation, and conductive heat bypass. The scenarios considered revealed the highest efficiency decay for convectionally loaded setups (up to 4.8%pts), followed by the impacts of contact resistances (up to 4.8%pts), by radiation (up to 0.56%pts), and by thermal conduction of a solid filling material within the voids of the module construction (up to 0.14%pts).

The Internet-of-things (IoT) has been gradually paving the way for the pervasive connectivity of wireless networks. Due to the ability to connect a number of devices to the Internet, many applications of IoT networks have recently been proposed. Though these applications range from industrial automation to smart homes, healthcare applications are the most critical. Providing reliable connectivity among wearables and other monitoring devices is one of the major tasks of such healthcare networks. The main source of power for such low-powered IoT devices is the batteries, which have a limited lifetime and need to be replaced or recharged periodically. In order to improve their lifecycle, one of the most promising proposals is to harvest energy from the ambient resources in the environment. For this purpose, we designed an energy harvesting protocol that harvests energy from two ambient energy sources, namely radio frequency (RF) at 2.4 GHz and thermal energy. A rectenna is used to harvest RF energy, while the thermoelectric generator (TEG) is employed to harvest human thermal energy. To verify the proposed design, extensive simulations are performed in Green Castalia, which is a framework that is used with the Castalia simulator in OMNeT++. The results show significant improvements in terms of the harvested energy and lifecycle improvement of IoT devices.

Abstract Objectives To provide an overview of the clot viscoelastic testing technology and to describe its utility in guiding blood product transfusions. Methods A case scenario will be discussed as well as interpretation of thromboelastography (TEG) tracings. In addition, literature examining the utility of viscoelastic testing in guiding patient management and blood product transfusions will be reviewed. Results TEG/rotational thromboelastometry (ROTEM) is useful in evaluating clot kinetics in trauma and acutely bleeding patients. TEG/ROTEM parameters are reflective of values measured using standard coagulation assays; however, TEG/ROTEM parameters are more rapidly available and more costly. TEG and ROTEM are used in three main settings: cardiac surgery, liver transplantation, and trauma to assess global hemostasis and administration of blood products. Conclusions TEG/ROTEM can be helpful in guiding resuscitation and blood product transfusion. Several studies have demonstrated a reduction in transfusion of blood components with TEG/ROTEM; however, other studies have suggested that TEG/ROTEM is not clinically effective in guiding transfusion.

Thermoelectric generators (TEGs) can convert heat to electricity through all‐solid‐state structure, which makes them suitable for energy recovery in cold environments. However, cryogenic TEG development faces dual challenges: severe power factor (PF) degradation and interfacial failures due to thermal expansion mismatch at module‐electrode junctions. In this work, a high PF is reported up to 10.5 mW m−1 K−2 at room temperature in carbon nanotube (CNT) films achieved by a developed material‐processing strategy with an annealing treatment method to carefully optimize the chlorosulfonic acid (CSA) doping level included. This PF value is close to some of state‐of‐the‐art inorganic thermoelectric materials at room temperature, which varies in 20% over a temperature range of 100–298 K that is superior to most of the state‐of‐the‐art inorganic thermoelectric materials (25%–70%). Spectra demonstrate that the CSA doping is a physical adsorption process, which is successfully fitted by the pseudo‐second‐order kinetic model. In addition, a single‐piece rollable TEG is fabricated to mitigate interfacial stresses, and this TEG maintained exceptional flexibility and structural integrity under cryogenic thermal cycling. Furthermore, a miniature thermoelectric power station is fabricated through integrating the rolled TEGs, which demonstrates the promising application of CNT based TEGs in cold environments. High power factor CNT of 10.5 mW m−1 K−2 at 298 K achieved by a developed material‐processing strategy exhibited a small variation by 20% in the temperature range of 100–298 K which surpassed most inorganic materials (25‐70%). The CNT film‐based single‐piece TEG showed exceptional ultra‐low temperature tolerance and great flexibility, which is promising for energy recovery in cold environments.

Thermophotovoltaics (TPVs) convert predominantly infrared wavelength light to electricity via the photovoltaic effect, and can enable approaches to energy storage 1 , 2 and conversion 3 – 9 that use higher temperature heat sources than the turbines that are ubiquitous in electricity production today. Since the first demonstration of 29% efficient TPVs (Fig. 1a ) using an integrated back surface reflector and a tungsten emitter at 2,000 °C (ref. 10 ), TPV fabrication and performance have improved 11 , 12 . However, despite predictions that TPV efficiencies can exceed 50% (refs. 11 , 13 , 14 ), the demonstrated efficiencies are still only as high as 32%, albeit at much lower temperatures below 1,300 °C (refs. 13 – 15 ). Here we report the fabrication and measurement of TPV cells with efficiencies of more than 40% and experimentally demonstrate the efficiency of high-bandgap tandem TPV cells. The TPV cells are two-junction devices comprising III–V materials with bandgaps between 1.0 and 1.4 eV that are optimized for emitter temperatures of 1,900–2,400 °C. The cells exploit the concept of band-edge spectral filtering to obtain high efficiency, using highly reflective back surface reflectors to reject unusable sub-bandgap radiation back to the emitter. A 1.4/1.2 eV device reached a maximum efficiency of (41.1 ± 1)% operating at a power density of 2.39 W cm –2 and an emitter temperature of 2,400 °C. A 1.2/1.0 eV device reached a maximum efficiency of (39.3 ± 1)% operating at a power density of 1.8 W cm –2 and an emitter temperature of 2,127 °C. These cells can be integrated into a TPV system for thermal energy grid storage to enable dispatchable renewable energy. This creates a pathway for thermal energy grid storage to reach sufficiently high efficiency and sufficiently low cost to enable decarbonization of the electricity grid. Two-junction TPV cells with efficiencies of more than 40% are reported, using an emitter with a temperature between 1,900 and 2,400 °C, for integration into a TPV system for thermal energy grid storage.

Background The goal of this study is to determine the presence of platelet dysfunction in patients with traumatic brain injury (TBI). The mechanisms underlying the coagulopathy associated with TBI remain elusive. The question of platelet dysfunction in TBI is unclear. Methods This was a prospective observational study conducted at Memorial Hospital of South Bend, IN, and Denver Health Medical Center, CO. A total of 50 patients sustaining TBI, and not under treatment with anticoagulants or platelet inhibitors, were analyzed utilizing modified thromboelastography (TEG) with platelet mapping (TEG/PM), along with standard coagulation tests. Results Compared to normal controls, patients with severe TBI had a significantly increased percentage of platelet ADP and arachidonic acid (AA) receptor inhibition. Furthermore, the percentage of ADP inhibition distinguished between survivors and non-survivors in patients with TBI (Mann–Whitney test, P  = 0.035). ADP inhibition correlates strongly with severity of TBI (Mann–Whitney test, P  = 0.014), while AA inhibition did not. Conclusion These data indicate that early platelet dysfunction is prevalent after severe TBI, can be measured in a point-of-care setting using TEG/PM, and correlates with mortality. The mechanism responsible for this platelet dysfunction and associated implications for TBI management remains to be defined.

Major hemorrhage is often associated with trauma-induced coagulopathy. Targeted blood product replacement could achieve faster hemostasis and reduce mortality. This study aimed to investigate whether thromboelastography (TEG®) goal-directed transfusion improved blood utilization, reduced mortality, and was cost effective. Data were prospectively collected in a U.K. level 1 trauma center, in patients with major hemorrhage one year pre- and post-implementation of TEG® 6s Hemostasis Analyzers. Mortality, units of blood products transfused, and costs were compared between groups. Patient demographics in pre-TEG (n = 126) and post-TEG (n = 175) groups were similar. Mortality was significantly lower in the post-TEG group at 24 h (13% vs. 5%; p = 0.006) and at 30 days (25% vs. 11%; p = 0.002), with no difference in the number or ratio of blood products transfused. Cost of blood products transfused was comparable, with the exception of platelets (average £38 higher post-TEG). Blood product wastage was significantly lower in the post-TEG group (1.8 ± 2.1 vs. 1.1 ± 2.0; p = 0.002). No statistically significant difference in cost was observed between the two groups (£753 ± 651 pre-TEG; £830 ± 847 post-TEG; p = 0.41). These results demonstrate TEG 6s-driven resuscitation algorithms are associated with reduced mortality, reduced blood product wastage, and are cost neutral compared to standard coagulation tests.