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The two-dimensional laser-based Ångstrom method measures the in-plane thermal properties for anisotropic film-like materials. It involves periodic laser heating at the center of a suspended film sample and records its transient thermal response by infrared imaging. These spatiotemporal temperature data must be analyzed to extract the unknown thermal conductivity values in the orthotropic directions, an inverse parameter fitting problem. Previous demonstration of the metrology technique used a least-squares fitting method that relies on numerical differentiation to evaluate the second-order partial derivatives in the differential equation describing transient conduction in the physical system. This fitting approach is susceptible to measurement noise, introducing high uncertainty in the extracted properties when working with noisy data. For example, when noise of a signal-to-noise ratio of 10 is added to simulated amplitude and phase data, the error in the extracted thermal conductivity can exceed 80%. In this work, we introduce a new alternative inverse parameter fitting approach using physics-informed neural networks (PINNs) to increase the robustness of the measurement technique for noisy temperature data. We demonstrate the effectiveness of this approach even for scenarios with extreme levels of noise in the data. Specifically, the PINN-approach accurately extracts the properties to within 5% of the true values even for high noise levels (a signal-to-noise ratio of 1). This offers a promising avenue for improving the robustness and accuracy of advanced thermal metrology tools that rely on inverse parameter fitting of temperature data to extract thermal properties. [ABSTRACT FROM AUTHOR]

Gas‐liquid flows through packed bed reactors (PBRs) are challenging to predict due to the tortuous flow paths that fluid interfaces must traverse. Experiments at the International Space Station showed that bubble and pulse flows are predominately observed under microgravity conditions, while the trickle and spray flows observed under terrestrial conditions are not present in microgravity. To understand the physics behind the former experiments, we simulate bubble flow through a PBR for different packing‐particle‐diameter‐based Weber numbers and under different gravity conditions. We demonstrate different pore‐scale mechanisms, such as capillary entrapment, buoyancy entrapment, and inertia‐induced bubble displacement. Then, we perform a quantitative analysis by introducing new dynamic scales, dependent upon the evolving gas‐liquid interfacial area, to understand the dynamic trade‐offs between the inertia, capillary, and buoyancy forces on a bubble passing through a PBR. This analysis leads us to define new dimensionless Weber‐like numbers that delineate bubble entrapment from bubble displacement. [ABSTRACT FROM AUTHOR]

Thermal greases, often used as thermal interface materials, are complex paste-like mixtures composed of a base polymer in which dense metallic (or ceramic) filler particles are dispersed to improve the heat transfer properties of the material. They have complex rheological properties that impact the performance of the thermal interface material over its lifetime. We perform rheological experiments on thermal greases and observe both stress relaxation and stress buildup regimes. This time-dependent rheological behavior of such complex fluid-like materials is not captured by steady shear-thinning models often used to describe these materials. We find that thixo-elasto-visco-plastic (TEVP) and nonlinear-elasto-visco-plastic (NEVP) constitutive models characterize the observed stress relaxation and buildup regimes, respectively. Specifically, we use the models within a data-driven approach based on physics-informed neural networks (PINNs). PINNs are used to solve the inverse problem of determining the rheological model parameters from the dynamic response in experiments. These training data are generated by startup flow experiments at different (constant) shear rates using a shear rheometer. We validate the "learned" models by comparing their predicted shear stress evolution to experiments under shear rates not used in the training datasets. We further validate the learned TEVP model by solving a forward problem numerically to determine the shear stress evolution for an input step-strain profile. Meanwhile, the NEVP model is further validated by comparison to a steady Herschel–Bulkley fit of the material's flow curve. [ABSTRACT FROM AUTHOR]

High heat fluxes generated in electronics and semiconductor packages require materials with high thermal conductivity to effectively diffuse the heat and avoid local hotspots. Engineered heat spreading materials typically exhibit anisotropic conduction behavior due to their composite construction. The design of thermal management solutions is often limited by the lack of fast and accurate characterization techniques for such anisotropic materials. A popular technique for measuring the thermal diffusivity of bulk materials is the Ångstrom method, where a thin strip or rod of material is heated periodically at one end, and the corresponding transient temperature profile is used to infer the thermal diffusivity. However, this method is generally limited to the characterization of one-dimensional samples and requires multiple measurements with multiple samples to characterize anisotropic materials. Here, we present a new measurement technique for characterizing the isotropic and anisotropic in-plane thermal properties of thin films and sheets as an extension of the one-dimensional Ångstrom method and other lock-in thermography techniques. The measurement leverages non-contact infrared temperature mapping to measure the thermal response from laser-based periodic heating at the center of a suspended thin film sample. Uniquely, our novel data extraction method does not require precise knowledge of the boundary conditions. To validate the accuracy of this technique, numerical models are developed to generate transient temperature profiles for hypothetical anisotropic materials with known properties. The resultant temperature profiles are processed through our fitting algorithm to extract the in-plane thermal conductivities without knowledge of the input properties of the model. Across a wide range of in-plane thermal conductivities, these results agree well with the input values. Experiments demonstrate the approach for a known isotropic reference material and an anisotropic heat spreading material. The limits of accuracy of this technique are identified based on the experimental and sample parameters. Further standardization of this measurement technique will enable the development and characterization of engineered heat spreading materials with desired anisotropic properties for various applications. [ABSTRACT FROM AUTHOR]

The popularisation of virtual mobility offers opportunities to reconsider power imbalances among different actors in higher education and to affirm the centrality of student agency and diversity. This article explores possibilities for applying the Students as Partners (SaP) approach to virtual mobility in order to empower students and foster reciprocal and ethical interactions. Drawing on interviews with students involved in an action research project, the article highlights the roles and perspectives of students in formulating authentic intercultural exchange experiences online. The findings suggest that application of the SaP framework reorganises students' agentic capacities and allows them to flourish in a way which, in turn, shifts the power balance in international learning and contributes to the ongoing re-configuration of approaches to internationalisation beyond the educator/student binary. [ABSTRACT FROM AUTHOR]

Thermal conductivity integral models including a suppression function to account for boundary scattering have had considerable success in explaining and predicting the thermal conductivity of nanostructures. However, the suppression function is analytically defined only for some simple structures, e.g., thin films and nanowires. For arbitrary nanostructures, Monte Carlo (MC)-based methods have been developed to calculate the suppression function. Here, we focus on two main types of MC-based methods: path sampling methods and ray tracing simulations. For the path sampling method, a more computationally efficient sampling algorithm is proposed based on the analytical solution of the average distance phonons can travel before a collision. The physical meaning of the path sampling method is rigorously given for the first time by comparing to the analytical solution of the Boltzmann Transport Equation for symmetric structures. Several limitations of the path sampling method are discussed based on assumptions in the derivation. Ray tracing simulations are well defined when a converged boundary mean free path (MFP) can be found. However, convergence is not guaranteed for arbitrary structures. More generally, we propose a modified formula to approximate the full-range suppression function with a characteristic length, which is determined by fitting to the calculated suppression function at selected MFPs. Ultimately, the accuracy of each calculated suppression function is evaluated by comparing the calculated thermal conductivity accumulation function for nanostructures including thin films, nanowires, and anisotropic modulated nanostructures. Our results provide guidance for selecting the appropriate techniques for calculating the suppression function and predicting the thermal conductivity of nanostructures. [ABSTRACT FROM AUTHOR]

We study 4d Friedmann-Lemaître-Robertson-Walker cosmologies obtained from time-dependent compactifications of Type IIA 10d supergravity on various classes of 6d manifolds (Calabi-Yau, Einstein, Einstein-Kähler). The cosmologies we present are universal in that they do not depend on the detailed features of the compactification manifold, but only on the properties which are common to all the manifolds belonging to that class. Once the equations of motion are rewritten as an appropriate dynamical system, the existence of solutions featuring a phase of accelerated expansion is made manifest. The fixed points of this dynamical system, as well as the trajectories on the boundary of the phase space, correspond to analytic solutions which we determine explicitly. Furthermore, some of the resulting cosmologies exhibit eternal or semi-eternal acceleration, whereas others allow for a parametric control on the number of e-foldings. At future infinity, one can achieve both large volume and weak string coupling. Moreover, we find several smooth accelerating cosmologies without Big Bang singularities: the universe is contracting in the cosmological past (T < 0), expanding in the future (T > 0), while in the vicinity of T = 0 it becomes de Sitter in hyperbolic slicing. We also obtain several cosmologies featuring an infinite number of cycles of alternating periods of accelerated and decelerated expansions. [ABSTRACT FROM AUTHOR]

Classical flux compactifications contribute to a well-controlled corner of the string landscape, therefore providing an important testing ground for a variety of conjectures. We focus here on type II supergravity compactifications on 6d group manifolds towards 4d maximally symmetric spacetimes. We develop a code where the truncation to left-invariant scalars and the dimensional reduction to a 4d theory are automated, for any possible configuration of Op-planes and Dp-branes. We then prove that any such truncation is consistent. We further compute the mass spectrum and analyse the stability of many de Sitter, Minkowski or anti-de Sitter solutions, as well as their consistency with swampland conjectures. [ABSTRACT FROM AUTHOR]

We classified in [1] certain 10d supergravity solutions with a 4d de Sitter, Minkowski or anti-de Sitter spacetime. We then found new solutions in previously unexplored classes. In this paper we study their properties, compare them to swampland conjectures, and make new observations. Using new numerical tools, we first identify all Lie algebras underlying the 6d group manifolds, allowing us to discuss their compactness. We then investigate scale separation, and prove related no-go theorems. Last but not least, we automatize and analyze the stability of all solutions. This leads us to propose the Massless Minkowski Conjecture, claiming the systematic presence of a 4d flat direction. [ABSTRACT FROM AUTHOR]

We classify solutions of 10d type IIA/B supergravities with orientifolds, on a 4d maximally symmetric spacetime times a 6d group manifold. We then look for new solutions in previously unexplored solution classes, and find some: (anti-) de Sitter solutions with intersecting O4, O6 and D6, or Minkowski solutions with 3 intersecting O5, among others. We provide the numerical code that we developed for this purpose. We also prove new no-go theorems against (anti-) de Sitter solutions. We finally conjecture the absence of de Sitter solution for 2 or less intersecting source sets, implying that a 4d effective theory with de Sitter is at most N = 1 supersymmetric. [ABSTRACT FROM AUTHOR]

The tribological behavior of tungsten carbide–cobalt materials is influenced by the cobalt content and the WC grains size. The main wear mechanisms in these materials are cobalt depletion, intergranular cracks, and WC grain cleavages. More specifically, coarse WC grains favor the apparition of transgranular cracks during sliding friction tests. A promising way to access in real-time blinded tribological contacts is the technique of acoustic emission (AE). This study clearly identifies transgranular cracks in AE signals. The AE energy and frequency of this mechanism were experimentally associated with the size of the transgranular cracks. A mechanical model based on the classical beam theory and harmonic motion equations confirms these relations. The AE centroid period (i.e., inverse of the centroid frequency) increases linearly with the size of the transgranular cracks. The AE energy increases linearly with the cube of the transgranular cracks length. [ABSTRACT FROM AUTHOR]

Membrane proteins are essential for cellular growth, signalling and homeostasis, making up a large proportion of therapeutic targets. However, the necessity for a solubilising agent to extract them from the membrane creates challenges in their structural and functional study. Although amphipols have been very effective for single-particle electron cryo-microscopy (cryoEM) and mass spectrometry, they rely on initial detergent extraction before exchange into the amphipol environment. Therefore, circumventing this pre-requirement would be a big advantage. Here we use an alternative type of amphipol: a cycloalkane-modified amphiphile polymer (CyclAPol) to extract Escherichia coli AcrB directly from the membrane and demonstrate that the protein can be isolated in a one-step purification with the resultant cryoEM structure achieving 3.2 Å resolution. Together this work shows that cycloalkane amphipols provide a powerful approach for the study of membrane proteins, allowing native extraction and high-resolution structure determination by cryoEM. Higgins et al. present a cycloalkane-modified amphiphilic polymer that can provide direct extraction of membrane proteins for Cryo-EM analysis. They show its utility by extracting and solving the structure of AcrB to a high resolution of 3.2 Å by single particle cryo-EM. [ABSTRACT FROM AUTHOR]

Thermal switches have gained intense interest recently for enabling dynamic thermal management of electronic devices and batteries that need to function at dramatically varied ambient or operating conditions. However, current approaches have limitations such as the lack of continuous tunability, low switching ratio, low speed, and not being scalable. Here, a continuously tunable, wide-range, and fast thermal switching approach is proposed and demonstrated using compressible graphene composite foams. Large (~8x) continuous tuning of the thermal resistance is achieved from the uncompressed to the fully compressed state. Environmental chamber experiments show that our variable thermal resistor can precisely stabilize the operating temperature of a heat generating device while the ambient temperature varies continuously by ~10 °C or the heat generation rate varies by a factor of 2.7. This thermal device is promising for dynamic control of operating temperatures in battery thermal management, space conditioning, vehicle thermal comfort, and thermal energy storage. Current designs of thermal switches are limited by a lack of continuous tunability, low switching ratio, low speed, and not being scalable. Here the authors report a continuously tunable, wide-range, fast, and cost effective thermal switching approach that is demonstrated using compressible graphene composite foams. [ABSTRACT FROM AUTHOR]

A cascaded multicore vapor chamber (CMVC) is designed for dissipating heat from high-flux hotspots simultaneously with a high-total-power background. Current thermal management strategies rely on spreading high local heat fluxes by conduction in the lid of electronics packages. Embedding vapor chambers (VCs) within the lid is an attractive option to directly address intrapackage hotspots. We investigate the design of intralid VCs, for a generic device having a total heat load of 476 W having a background heat flux of 0.75 W/mm2, with hotspots of 8 W/mm2 over a 1-mm2 area. A conventional VC design, having a single vapor core, will require a thick evaporator wick to avoid the capillary limit for large total power. The necessity for a thick wick then imposes a large thermal conduction resistance when the VC is exposed to high heat flux hotspots. The proposed CMVC architecture aims to address this limitation. The cascaded architecture comprises a bottom-tier VC having an array of multiple small vapor cores for spreading heat from the small hotspots. These small vapor cores have short paths of liquid return to the evaporator, such that they can handle their footprint heat load while using thin wicks, resulting in a low hotspot thermal resistance. Furthermore, local dampening of the hotspots by the bottom tier then reduces the thermal conduction resistance across the necessarily thick wick in the top tier. Hence, the cascaded architecture has the potential to significantly reduce the overall thermal resistance, relative to a single tier. To substantiate this design rationale, experiments are performed to illustrate that the resistance of a commercial VC can be significantly reduced by interfacing the heat source with an intermediate heat spreader. Reduced-order models are then used to understand the effect of the wick properties (porosity and particle size) and geometric parameters on the thermal performance of the CMVC for the representative power map. The optimal CMVC design offers a thermal resistance (0.66 K/W) that is significantly lower compared to a conventional single-core VC (1.76 K/W) owing to a reduction in the conduction resistances across the internal wicks. That parametric optimization results demonstrate that the thermal resistance of the CMVC is more sensitive to the wick porosity compared to the particle diameter. Furthermore, there exists a wide range of wick properties and vapor core sizes for which near-optimum thermal performance can be attained, which is particularly attractive from the standpoint of flexibility in design and manufacturing. [ABSTRACT FROM AUTHOR]

With advances in flexible and wearable device technology, thermal regulation will become increasingly important. Fabrics and substrates used for such applications will be required to effectively spread any heat generated in the devices to ensure user comfort and safety, while also preventing overheating of the electronic components. Commercial fabrics consisting of ultra-high molecular weight polyethylene (UHMW-PE) fibers are currently used in personal body armor and sports gear owing to their high strength, durability, and abrasion resistance. In addition to superior mechanical properties, UHMW-PE fibers exhibit very high axial thermal conductivity due to a high degree of polymer chain orientation. However, these materials have not been widely explored for thermal management applications in flexible and wearable devices. Assessment of their suitability for such applications requires characterization of the thermal and mechanical properties of UHMW-PE in the fabric form that will ultimately be used to construct heat spreading materials. Here, we use advanced techniques to characterize the thermal and mechanical properties of UHMW-PE fabrics, as well as other conventional flexible materials and fabrics. An infrared microscopy-based approach measures the effective in-plane thermal conductivity, while an ASTM-based bend testing method quantifies the bending stiffness. We also characterize the effective thermal behavior of fabrics when subjected to creasing and thermal annealing to assess their reliability for relevant practical engineering applications. Fabrics consisting of UHMW-PE fibers have significantly higher thermal conductivities than the benchmark conventional materials while possessing good mechanical flexibility, thereby showcasing great potential as substrates for flexible and wearable heat spreading application. [ABSTRACT FROM AUTHOR]

Wine discourse has been readily found in the forms of wine tasting notes, reviews, advertisements, poetry, and classical literature. The popularity of Japanese wine manga, however, introduces a new venue for wine discourse and vector along which academic analysis can be conducted. In this paper, we seek to expand upon prior research on wine semantics and wine discourse by applying the framework of Cultural Linguistics to the subgenre of wine manga. Based on an original, Japanese-French bilingual corpus developed from the graphic novels Sommelier and Kami no Shizuku – each an epoch-making work, highly didactic in nature – our analysis focuses on the conceptual metaphor wine is a person. Results illustrate the Japanese authors' contribution to the figurative language used in wine discourse. In other words, in Japan just as in France, wine is a person, and there is a shared cultural understanding of wine, or traits therein, being the embodiment of the human. [ABSTRACT FROM AUTHOR]

Cultural Literacy is an emerging, interdisciplinary approach in literary and cultural studies. As such, it seeks to grow and benefit from different fields and disciplines. Whilst there are differences between Cultural Literacy and Cultural Linguistics, there is common ground between them, and Cultural Literacy can draw immense benefit from the cross-pollination of ideas with Cultural Linguistics. This article explores the interconnections between Cultural Literacy and Cultural Linguistics, particularly in relation to intercultural communication. The article compares a number of differences and similarities between Cultural Linguistics and Cultural Literacy, in particular, the notions of 'cultural conceptualisations' and 'metacultural competence' as they are currently applied in Cultural Linguistics. The article discusses the possible use of cultural conceptualisations in Cultural Literacy, arguing that these can support the development of cultural literacy skills, by providing a strong, useful framework to enhance what is known as 'cultural readability'. Furthermore, the paper looks at the application of strategies for metacultural competence hitherto associated with Cultural Linguistics in the context of Cultural Literacy, arguing that such strategies illustrate practical steps that can be taken toward developing an individual's Cultural Literacy skills. Lastly, the article suggests that the ideas of transcultural competence, critical reflection and cultural readability, often used in Cultural Literacy, can enrich new discussions on Cultural Linguistics. [ABSTRACT FROM AUTHOR]

Large area highly crystalline MoS2 and WS2 thin films were successfully grown on different substrates using radio-frequency magnetron sputtering technique. Structural, morphological and thermoelectric transport properties of MoS2, and WS2 thin films have been investigated systematically to fabricate high-efficient thermal energy harvesting devices. X-ray diffraction data revealed that crystallites of MoS2 and WS2 films are highly oriented in 002 plane with uniform grain size distribution confirmed through atomic force microscopy study. Surface roughness increases with substrate temperature and it plays a big role in electron and phonon scattering. Interestingly, MoS2 films also display low thermal conductivity at room temperature and strongly favors achievement of higher thermoelectric figure of merit value of up to 1.98. Raman spectroscopy data shows two distinct MoS2 vibrational modes at 380 cm−1 for E12g and 410 cm−1 for A1g. Thermoelectric transport studies further demonstrated that MoS2 films show p-type thermoelectric characteristics, while WS2 is an n-type material. We demonstrated high efficient pn-junction thermoelectric generator device for waste heat recovery and cooling applications. [ABSTRACT FROM AUTHOR]

Maghemite nanoparticles have been sought after for electronic, biomedical, and environment applications, for their soft ferrimagnetic properties and large coercivity. While their magnetic properties are well characterized, their nonmagnetic properties are currently not available because maghemite is prepared as nanoparticles and their bulk forms often have contaminants. In this work, thermodynamically unstable maghemite nanoparticles are cold sintered (130‐250°C) to form bulk samples with submicron‐size grains. Electrical and thermal conductivities of maghemite were evaluated for the first time: 3.5 × 10−7 S/m and 0.86‐1.30 W/(mK). The relative densities of these cold‐sintered samples are low (55.9%‐64.2%) but comparable with or slightly lower than those previously achieved with higher sintering temperature (~55% at 500°C and ~76% at 1250°C). Such porous maghemite samples with large surface areas can potentially be used as an anode of lithium‐ion batteries, while further densification will be pursued in the future by sintering process modification. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) are complex, heterogeneous systems with coupled electrochemical and thermal phenomena that lead to elevated temperatures, which, in turn, limit safety, reliability, and performance. Despite years of research, there are still open questions about the electrochemical-thermal phenomena within battery cells. This article highlights recent advances in thermal characterization and modeling of LIBs with an emphasis on the multi-scale aspect of battery systems: from the microscale electrode components to the macroscale battery packs. Both heat generation and thermal properties (thermal conductivity and specific heat capacity) are impacted by battery capacity, charge/discharge rate, ambient conditions, and the underlying microstructure. Understanding thermal phenomena and designing batteries to prevent thermal runaway requires multiscale efforts from the microstructure of the electrodes to the overall system behavior. Experimental efforts have focused on both property and performance characterization, as well as development of new battery chemistries for improved performance and new designs for improved thermal management. Past numerical modeling work ranges from computationally efficient lumped approaches to high fidelity microstructural finite element models. Ultimately, coupled electrochemical-thermal investigations (both numerical and experimental) are required to further improve the performance and reliability of batteries, and to prevent thermal runaway. This perspective article provides insight into directions to improve these approaches with the goal of informing design of batteries with improved performance, safety, and reliability. [ABSTRACT FROM AUTHOR]

In the fast evolving context of globalised higher education, increasing academic mobility requires constant adaptation from institutions. This paper focuses on intercultural enrichment programs, often perceived as mere "add ons" to study abroad, and usually designed as optional not-for-credit extracurricular offerings. We investigate how institutions can give more value to and deepen the intercultural learning of more students in spite of constraints of time and of formal curriculum during short-term study abroad experiences. Resulting from a close collaboration between academic and administrative staff based at different campuses, this paper provides a critical analysis of the benefits and challenges involved in developing co-curricular intercultural enrichment programs that support formal curriculum during study abroad. Practical recommendations are based on a transdisciplinary program developed in Italy by an Australian university that has branch campuses in different countries. We also discuss the "digitally enhanced" aspects of the program which facilitate the in-class activities. [ABSTRACT FROM AUTHOR]

Over the past two decades, significant progress in the thermal metrology for thin films and wires has enabled new understanding of the thermal conductivity of nanostructures. However, a large variation in the measured thermal conductivity of similar nanostructured samples has been observed. In addition to potential differences from sample-to-sample, measurement uncertainty contributes to the observed variation in measured properties. Many now standard micro/nanoscale thermal measurement techniques require extensive calibration of the properties of the substrate and support structures and this calibration contributes to uncertainty. Within this work, we develop a simple, direct differential electrothermal measurement of thermal conductivity of micro/nanoscale sample films by extending conventional steady state electrothermal approaches. Specifically, we leverage a cross-beam measurement structure consisting of a suspended, composite heater beam (metal on silicon) with the sample structure (silicon) extending at a right angle from the center of the heater beam, in a configuration similar to the T-type measurements used for fibers and nanotubes. To accurately resolve the thermal conductivity of the sample, the steady-state Joule heating response of the cross-beam structure is measured. Then, the sample is detached from the heater beam with a Focused Ion Beam (FIB) tool enabling direct characterization of the composite heater beam thermal properties. The differential measurement of the structure before and after FIB cut enables direct extraction of the sample thermal conductivity. The effectiveness of this differential measurement technique is demonstrated by measuring thermal conductivity of a 200 nm silicon layer. Additionally, this new method enables investigation of the accuracy of conventional approaches for extracting sample thermal conductivity with the composite beam structure and conventional comparative approaches. The results highlight the benefits of the direct differential method for accurate measurements with minimal assumptions. [ABSTRACT FROM AUTHOR]

Nanosecond time-domain thermoreflectance (ns-TDTR) is an all optical method of determining independently a variety of thermal parameters of both homogeneous and layered materials. Despite its relative experimental simplicity, the sensitivity of the temperature decay (measured by the transient reflectivity signal) to the relevant thermal properties has yet to be fully characterized. In principle, it is possible to simultaneously extract multiple thermal parameters from a single measurement. In practice, however, changes to several of these parameters may result in experimentally indistinguishable variations to the transient reflectivity signal. In this work, we focus on investigating thermal properties of bulk material and the contact resistance between the thin-film coating that is needed for the ns-TDTR method and the bulk substrate. To extract multiple properties from one temperature decay trace, we divide the data into temporal sub-regions known to be influenced to different degrees by each individual thermal parameter and iteratively fit with a 1-D heat conduction model to independently determine the contact resistance and cross-plane thermal conductivity. [ABSTRACT FROM PUBLISHER]

The thermal conductance across solid-liquid interfaces is of interest for many applications. Using time-domain thermoreflectance, we measure the thermal conductance across self-assembled monolayers, grown on Au, to ethanol. We systematically study the effect of different functional groups and the alkyl chain length on the thermal conductance. The results show that adding this extra molecular layer can enhance the thermal transport across the solid-liquid interface. While the enhancement is up to 5 times from hexanedithiol, the enhancement from hexanethiol, undecanethiol, and hexadecanethiol is approximately a factor of 2. [ABSTRACT FROM AUTHOR]

The past two decades have witnessed the emergence and rapid growth of the research field of nanoscale thermal transport. Much of the work in this field has been fundamental studies that have explored the mechanisms of heat transport in nanoscale films, wires, particles, interfaces, and channels. However, in recent years there has been an increasing emphasis on utilizing the fundamental knowledge gained toward understanding and improving device and system performances. In this opinion article, an attempt is made to provide an evaluation of the existing and potential impacts of the basic research efforts in this field on the developments of the heat transfer discipline, workforce, and a number of technologies, including heat-assisted magnetic recording, phase change memories, thermal management of microelectronics, thermoelectric energy conversion, thermal energy storage, building and vehicle heating and cooling, manufacturing, and biomedical devices. The goal is to identify successful examples, significant challenges, and potential opportunities where thermal science research in nanoscale has been or will be a game changer. [ABSTRACT FROM AUTHOR]

Vertically aligned carbon nanotube (CNT) arrays can offer an attractive combination of high thermal conductance and mechanical compliance for thermal interface applications. These arrays require a reliable, thermally conductive bonding technique to enable integration into devices. This paper examines the use of a reactive metal bonding layer to attach and transfer CNT arrays to metal-coated substrates, and the thermal performance is compared with CNT arrays bonded with indium solder. Infrared microscopy is used to simultaneously measure the intrinsic thermal conductivity of the CNT array and the thermal boundary resistance of both the bonded and growth CNT interfaces over a range of applied compressive stresses. A coarse-grained molecular simulation is used to model the effects of compressive pressure on the CNT array thermal conductivity. Reactive metal bonding reduces the thermal boundary resistance to as low as 27 \mathrmmm^2\,\cdot K $\cdot $ \mathrm{W}^{-1} , which is more than an order of magnitude less than the nonbonded contact. [ABSTRACT FROM PUBLISHER]

Despite a long historical French presence in Vietnam, only 0.5% of Vietnamese people speak French today. As in other countries of South East Asia, language instruction in Vietnam has mainly focused on English for several decades. This paper provides an overview of a project called Trench bilingual classes'. The main aim of the study is to analyze the benefits and the challenges identified by local teachers and researchers who have been involved in this program. The data are extracted from a corpus of 62 out of 468 papers written in French and presented during the annual Seminar on Action Research organized from 1999 to 2009 in Cambodia, Laos and Vietnam. The analysis of this discursive resource illustrates an overall acknowledgment of the positive outcomes of the program. However, in concordance with studies of English language teaching in Vietnam, the pitfalls identified in our corpus indicate that the major challenge is the implementation of a learner-centered and an action-oriented pedagogy in an educational context generally qualified as traditional. By providing new insights on bilingual education in Vietnam, our study will contribute to the current debate regarding the sustainability of innovative language curricula and multilingual education in the Asian context. [ABSTRACT FROM AUTHOR]

Thermal interface materials (TIMs) based on vertically aligned carbon nanotube (VACNT) films promise the unusual combination of high thermal conductance and low elastic modulus, properties that are critical for TIM performance and reliability. This paper reports through-plane thermal conductivity, heat capacity, and boundary resistances measured using frequency domain thermoreflectance for seven VACNT films. The films are composed of single-walled carbon nanotubes grown using chemical vapor deposition on Si substrates and have thicknesses from 5.3 to 81 \mum. The top surfaces of the films are coated with 100-nm Ti and 100-nm Ag as a transducer layer for the thermoreflectance measurement. The roughness of the top surface of each sample is measured using atomic force microscopy. The average thermal conductivity of the films ranges from 2.1 to 3.5 W m^-1~K^-1 and the average heat capacity ranges from 5.5 to 9.3 J cm^-3~K^-1. The heat capacity of the films is used to calculate the volume fraction of tubes that contributes to thermal conduction. The CNT-metal boundary resistances are below 1 m^2~K~MW^-1 and the CNT-substrate resistance ranges from 3 to 80 m^2~K~MW^-1. Variations of the nanotube alignment and morphology throughout the film are also examined using scanning electron micrographs to provide a comprehensive analysis of these films. [ABSTRACT FROM AUTHOR]