Identification and characterization of the dominant thermal resistance in lithium-ion batteries using operando 3-omega sensors

Poor thermal transport within lithium-ion batteries fundamentally limits their performance, safety, and lifetime, in spite of external thermal management systems. All prior efforts to understand the origin of batteries' mysteriously high thermal resistance have been confined to ex situ measurements without understanding the impact of battery operation. Here, we develop a frequency-domain technique that employs sensors capable of measuring spatially resolved intrinsic thermal transport properties within a live battery while it is undergoing cycling. Our results reveal that the poor battery thermal transport is due to high thermal contact resistance between the separator and both electrode layers and worsens as a result of formation cycling, degrading total battery thermal transport by up to 70%. We develop a thermal model of these contact resistances to explain their origin. These contacts account for up to 65% of the total thermal resistance inside the battery, leading to far-reaching consequences for the thermal design of batteries. Our technique unlocks new thermal measurement capabilities for future battery research

Chronic Exposure to Low Frequency Noise at Moderate Levels Causes Impaired Balance in Mice

We are routinely exposed to low frequency noise (LFN; below 0.5 kHz) at moderate levels of 60–70 dB sound pressure level (SPL) generated from various sources in occupational and daily environments. LFN has been reported to affect balance in humans. However, there is limited information about the influence of chronic exposure to LFN at moderate levels for balance. In this study, we investigated whether chronic exposure to LFN at a moderate level of 70 dB SPL affects the vestibule, which is one of the organs responsible for balance in mice. Wild-type ICR mice were exposed for 1 month to LFN (0.1 kHz) and high frequency noise (HFN; 16 kHz) at 70 dB SPL at a distance of approximately 10–20 cm. Behavior analyses including rotarod, beam-crossing and footprint analyses showed impairments of balance in LFN-exposed mice but not in non-exposed mice or HFN-exposed mice. Immunohistochemical analysis showed a decreased number of vestibular hair cells and increased levels of oxidative stress in LFN-exposed mice compared to those in non-exposed mice. Our results suggest that chronic exposure to LFN at moderate levels causes impaired balance involving morphological impairments of the vestibule with enhanced levels of oxidative stress. Thus, the results of this study indicate the importance of considering the risk of chronic exposure to LFN at a moderate level for imbalance

Intellectual Disability and Epilepsy

This book also acknowledges that the impact on the person and on their carers always needs to be taken into account, with treatment programs established with a multi-faceted team approach in mind

Illuminating the life of GPCRs

The investigation of biological systems highly depends on the possibilities that allow scientists to visualize and quantify biomolecules and their related activities in real-time and non-invasively. G-protein coupled receptors represent a family of very dynamic and highly regulated transmembrane proteins that are involved in various important physiological processes. Since their localization is not confined to the cell surface they have been a very attractive "moving target" and the understanding of their intracellular pathways as well as the identified protein-protein-interactions has had implications for therapeutic interventions. Recent and ongoing advances in both the establishment of a variety of labeling methods and the improvement of measuring and analyzing instrumentation, have made fluorescence techniques to an indispensable tool for GPCR imaging. The illumination of their complex life cycle, which includes receptor biosynthesis, membrane targeting, ligand binding, signaling, internalization, recycling and degradation, will provide new insights into the relationship between spatial receptor distribution and function. This review covers the existing technologies to track GPCRs in living cells. Fluorescent ligands, antibodies, auto-fluorescent proteins as well as the evolving technologies for chemical labeling with peptide- and protein-tags are described and their major applications concerning the GPCR life cycle are presented

Enhanced Thermochemical Heat Capacity of Liquids: Molecular to Macroscale Modeling

Thermal fluids have many applications in the storage and transfer of thermal energy, playing a key role in heating, cooling, refrigeration, and power generation. However, the specific heat capacity of conventional thermal fluids, which is directly linked to energy density, has remained relatively low. To tackle this challenge, we explore a thermochemical energy storage mechanism that can greatly enhance the heat capacity of base fluids (by up to threefold based on simulation) by creating a solution with reactive species that can absorb and release additional thermal energy. Based on the classical theory of equilibrium thermodynamics, we developed a macroscale theoretical model that connects fundamental properties of the underlying reaction to the thermophysical properties of the liquids. This framework allows us to employ state-of-the-art molecular scale computational tools such as density functional theory calculations to identify and refine the most suitable molecular systems for subsequent experimental studies. Our approach opens up a new avenue for developing next-generation heat transfer fluids that may break traditional barriers to achieve high specific heat and energy storage capacity

Numerical modelling of boiling heat transfer in microchannels

In this paper we report the results of our modelling studies on two-phase forced convection in microchannels using water as the fluid medium. The study incorporates the effects of fluid flow rate, power input and channel geometry on the flow resistance and heat transfer from these microchannels. Two separate numerical models have been developed assuming homogeneous and annular flow boiling. Traditional assumptions like negligible single-phase pressure drop or fixed inlet pressure have been relaxed in the models making analysis more complex. The governing equations have been solved from the grass-root level to predict the boiling front. pressure drop and thermal resistance as functions of exit pressure and heat input. The results of both the models are compared to each other and with available experimental data. It is seen that the annular flow model typically predicts higher pressure drop compared to the homogeneous model. Finally, the model has also been extended to study the effects of non-uniform heat input along the flow direction. The results show that the non-uniform power map can have a very strong effect on the overall fluid dynamics and heat transfer. (C) 200

Enhanced Thermochemical Heat Capacity of Liquids: Molecular to Macroscale Modeling

Thermal fluids have many applications in the storage and transfer of thermal energy, playing a key role in heating, cooling, refrigeration, and power generation. However, the specific heat capacity of conventional thermal fluids, which is directly linked to energy density, has remained relatively low. To tackle this challenge, we explore a thermochemical energy storage mechanism that can greatly enhance the heat capacity of base fluids (by up to threefold based on simulation) by creating a solution with reactive species that can absorb and release additional thermal energy. Based on the classical theory of equilibrium thermodynamics, we developed a macroscale theoretical model that connects fundamental properties of the underlying reaction to the thermophysical properties of the liquids. This framework allows us to employ state-of-the-art molecular scale computational tools such as density functional theory calculations to identify and refine the most suitable molecular systems for subsequent experimental studies. Our approach opens up a new avenue for developing next-generation heat transfer fluids that may break traditional barriers to achieve high specific heat and energy storage capacity

Analysis of Nanofluid-Based Parabolic Trough Collectors for Solar Thermal Applications

Solar-to-thermal energy conversion technologies are an important and increasingly promising segment of our renewable energy technology future. Today, concentrated solar power (CSP) plants provide a method to efficiently store and distribute solar energy. Current industrial solar-to-thermal energy technologies employ selective solar absorber coatings to collect solar radiation, which suffer from low solar-to-thermal efficiencies at high temperatures due to increased thermal emission from selective absorbers. Solar absorbing nanofluids (a heat transfer fluid (HTF) seeded with nanoparticles), which can be volumetrically heated, are one method to improve solar-to-thermal energy conversion at high temperatures. To date, radiative analyses of nanofluids via the radiative transfer equation (RTE) have been conducted for low temperature applications and for flow conditions and geometries that are not representative of the technologies used in the field. In this work, we present the first comprehensive analysis of nanofluids for CSP plants in a parabolic trough configuration. This geometry was chosen because parabolic troughs are the most prevalent CSP technologies. We demonstrate that the solar-to-thermal energy conversion efficiency can be optimized by tuning the nanoparticle volume fraction, the temperature of the nanofluid, and the incident solar concentration. Moreover, we demonstrate that direct solar absorption receivers have a unique advantage over current surface-based solar coatings at large tube diameters. This is because of a nanofluid's tunability, which allows for high solar-to-thermal efficiencies across all tube diameters enabling small pressure drops to pump the HTF at large tube diameters