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The present work reports the physical, size and shape, flowability, drying and devolatilization properties of ground wood and ground bark particles. Mechanical sieving and image processing identify the size and shape of ground particles, respectively. Ground particles are dried at initial moisture contents of 0.30, 0.50, 0.70 and 0.90 (dry mass basis) and drying temperatures of 70, 100, 130 and 160 °C. Devolatilization rate of particles is measured using a thermogravimetric analyzer. Microscopic investigations show that wood particles are longer and thinner than bark particles. More spherical shape facilitates the flowability of the bark particles. Wood particles are cohesive and have poorer flowability properties than bark particles. Bark particles have a lower internal void fraction than wood particles. Denser structure of bark particles diminishes the drying and devolatilization rate and prolongs the heat and mass transfer process compared to the wood particles. [ABSTRACT FROM AUTHOR]

The human eye has been the center of many studies at thermographic level, has little blood supply, which allows to demonstrate that the change of temperature in the ocular surface can be an important indicator for the diagnosis of different pathologies. In this study, a methodology was designed and implemented by means of which the influence of human lachrymal function on the ocular surface (cornea) was analyzed at thermal level, using infra-red thermography in a sample of 40 people without ocular pathologies (20 men - 20 women between 18 and 28 years of age). It is shown that the tear function has a thermal effect which can be described by the rate of decrease of the corneal temperature in the blinking exercise; it is demonstrated that this thermal effect is similar for men and women and can be converted into a quantitative type base for the study and diagnosis of ocular pathologies such as dry eye syndrome (SOS) in which the tear function is severely affected. [ABSTRACT FROM AUTHOR]

Thixoforming involves heating different types of alloys to the semisolid state at high heating rates and forming in die-casting machines or conventional presses. At temperatures higher than the solidus and lower than the liquidus, the mush metal behaves like a high-viscosity thixotropic material. Therefore, determining the thermodynamic behavior of the solid-to-liquid transition is paramount to control thixoforming processes. This article describes a simple, novel experimental setup based on differential thermal analysis (DTA) for analyzing the phase transitions in an alloy heated using high heating rates typical of industrial applications. A365 alloy was chosen to demonstrate the effectiveness of the method as the phase transformations for this alloy in semisolid materials (SSM) processing are well understood. Samples were heated to 750 °C using constant linear heating rates of 5, 10, 15, 20, 25, 50, 75, 100 and 125 °C min in a Norax 25 kW 8 kHz induction furnace with an Omron E5CK temperature controller. AISI 316 austenitic stainless steel was used as the inert reference. Comparison of the results of DTA using the proposed method and the results of simulation with Thermo-Calc® indicates that the proposed in situ DTA device and its method is suitable for analyzing phase transitions when high heating rates are used. [ABSTRACT FROM AUTHOR]

This study aims to develop a novel composite Phase Change Material (PCM) using eco-friendly and low-cost components for an application of improving thermal inertia of building envelopes. The Coconut fat recovered from underused feedstocks was selected as a bio-based PCM for its good Thermal Energy Storage (TES) characteristics. This bio-based PCM was incorporated in a composite matrix prepared in the laboratory from natural clay and cellulose fibers. The direct immersion method with no vacuum treatment was followed as a simple incorporation process of the bio-based PCM into its matrix. The results of thermal and physicochemical characterizations show that the prepared composite-PCM has the potential to be used for passive TES in building envelopes in order to enhance their thermal inertia. [ABSTRACT FROM AUTHOR]

We use numerical simulations to design and optimize a set of miniaturized heat meter bars for high-resolution measurements of interfacial thermal transport across solid, contacting junctions ( $R_{T}$ ) and thermal conductivity within low-resistivity materials ( $\kappa$ ). We find that extreme care must be taken to design both the geometry of the heat meter bars and the cooling technique used to drive thermal transport across the junction. To reduce measurements of $R_{T}$ down to 0.1 mm2 $\cdot$ K/W, a channel heat sink is optimized to remove heat from the lower bar. Results suggest that in order to maintain a sufficient number of temperature measurements, the bar length can be no less than 3 mm in order to maintain a linear thermal gradient a sufficient distance away from the interface. Further reductions in heat meter bar length are insufficient to achieve corresponding reductions in $R_{T}$. To address this limitation, a jet impingement cooling technique is assessed. We find that a $2\times 3$ array of jets ( $D = 1$ mm) is sufficient to maintain a linear thermal gradient around the interface as the heat meter bar length is reduced below 5 mm. Using the jet impingement cooling technique described in this paper, measurements of $R_{T} = 0.01$ mm2 $\cdot$ K/W are found to be theoretically possible. This would represent a two-orders-of-magnitude improvement in the resolution of interfacial thermal resistance measurements made with steady-state thermal characterization techniques. The thermal challenges explored in this paper are critical to the design of instruments that can directly characterize the magnitude of heat flow permitted across high-performance thermal interface materials in electronics packaging systems. [ABSTRACT FROM AUTHOR]

The tendency of polymers to shrink upon cooling and to expand upon heating strongly affects polymer processing operations. Therefore, quantifying these properties through dilatometry is crucial. Existing setups to measure dilatometry are, however, mostly limited to solid samples, or are expensive and impractical to use. Moreover, upcoming forms of polymer processing such as additive manufacturing techniques or more commonly named 3D-printing techniques require these properties to be measured under atmospheric pressure, which is not possible with most of the existing setups. Therefore, this paper describes a novel method for pressure-free volumetric dilatometry that is able to characterize samples in both liquid and solid phase, and during liquid-solid transitions. The principle of the method is based on the use of a highly viscous confining fluid that, in combination with a simple piston-die sample container, offers a cheap, easy-to-use and safe method to measure volumetric dilatometry on a variety of samples. The method is verified by comparison with standards and data from literature. [ABSTRACT FROM AUTHOR]

A new multiple heat path dynamic compact model extraction method for LED packages with silicone domes is proposed. The method enables separate characterization of the LEDs dome and the main heat path. It is based on thermal transient analysis of LED configurations with and without the dome. The heat paths de-embedding procedure proposed significantly increases accuracy of the LED thermal characterization compared to a typical singular heat path approach. The method is demonstrated with a representative mid-power LED. The results are validated with steady-state FEA. Suppressed estimation errors of the heat path evaluation are indicated. [ABSTRACT FROM AUTHOR]

This study investigates for the first time the feasibility of isolating nanocellulose from several selected feedstocks via a novel Ni(II)-hydrolysis process, including lignocellulosic biomasses (oil palm trunk, banana peel and coconut husk) and processed biomasses (newspaper, tissue paper and cotton linter), with an obtained gravimetric yield ranging from 59.6 to 86.2%. The isolation of nanocellulose products from these selected feedstocks was verified by the successive removal of most of their non-cellulosic components (lignin and hemicellulose) and cellulose amorphous regions, the increase in the crystallinity index and the nanoscale of the individual crystals. Most importantly, the resultant nanocellulose products rendered better thermal stability than that of corresponding original sources, which are highly potential to be utilized as the new renewable sources of reinforcement materials with potential applications in bio-nanocomposites and thermoplastics. Therefore, this work proves the viability of direct production of nanocellulose from a variety of cellulosic sources by using Ni(II)-based transition metal salt catalyst. The results suggested that the concept of waste to wealth could be well executed from the obtained nanocellulose, which are greatly potential for various industrial applications. [ABSTRACT FROM AUTHOR]

Benzil monohydrazone based Schiff bases were synthesized and characterized by 1 H NMR, 13 C NMR, HRMS as well as by single crystal X-ray diffraction. The geometries of the compounds was optimized by the DFT method and the results were compared with the X-ray diffraction data. The HOMO and LUMO energy gap and also related parameters (electronic chemical potential (μ) and global hardness (η), global electrophilicity index (ω) and softness (s)) were obtained from ground state calculations. In addition, the thermal properties of the compounds were investigated by DTA–TGA. The results showed that the compounds have good thermal properties for practical applications as optic dye. [ABSTRACT FROM AUTHOR]

Nowadays, fiber-reinforced composites have gained attention due to their improved potential for replacing the conventional materials in various applications. Kenaf fiber has been widely used as reinforcement in composites over the past few years which is a most attractive alternative due to its rapid growth at different climatic conditions and ensuring low cost; kenaf fiber has gained some attention to replacing the glass fiber composite and making it purely an eco-friendly composite. However, for enhancing its properties in different applications, an appropriate characterization is very important. Hence, many researches have been conducted in recent years, for the characterization of kenaf fiber and its composites. In this paper, a state-of-the-art review of these characterizations is presented. [ABSTRACT FROM AUTHOR]

The development of steady-state thermal characterization techniques for AlGaN/GaN high-electron mobility transistors (HEMTs) has been used to measure the device’s peak temperature under DC conditions. Despite these methods enabling the accurate quantification of the device’s effective thermal resistance and power density dependence, transient thermometry techniques are necessary to understand the nanoscale thermal transport within the active GaN layer where the highly localized joule heating occurs. One technique that has shown the ability to achieve this is transient thermoreflectance imaging (TTI). The accuracy of TTI is based on using the correct thermoreflectance coefficient. In the past, alternative techniques have been used to adjust the thermoreflectance coefficient to match the correct temperature rise in the device. This paper provides a new method to accurately determine the thermoreflectance coefficient of a given surface and is validated via an electrical method: gate resistance thermometry (GRT). Close agreement is shown between the temperature rise of the passivated gate metal measured by TTI and the averaged gate temperature monitored by GRT. Overall, TTI can now be used to thermally map GaN HEMTs under pulsed conditions providing simultaneously a submicrosecond temporal resolution and a submicrometer spatial resolution. [ABSTRACT FROM AUTHOR]

The papermaking industry has been using the wet-laid process to suspend paper pulp-derived fibers in water and drain the solution through a forming mesh. This process has recently been adopted to produce non-woven, wet-laid fiber-reinforced polymer matrix composite mats. The mats can be postmolded into different complex shapes using compression molding or related processes. The objective of this study was to produce composite panels from wet-laid mats and observe the effect of chemicals used during the process on the mechanical and thermal characteristics of the resulting composite. Two sets of mats were processed using recycled glass fiber with Polyamide 6 (PA6). Flocculent, dispersant and binder (poly(vinyl alcohol) (PVOH)) were added to one of the mats, and the second mat was processed without these chemicals. The addition of these chemicals enhanced the fiber distribution and reduced processing defects in the mats. This was reflected in the mechanical properties of the final product. It was noticed that the flocculent, dispersant and binder volatilized during the compression molding step. Hence, the additives were found not to affect the thermal properties of the consolidated part. [ABSTRACT FROM AUTHOR]

The technology to produce compatibilized blends of liquid crystalline polymer and highly amorphous cyclic olefin copolymers through two novel approaches were studied. The first approach was to use silane-functionalized halloysite nanotube as nonspecific compatibilizer and the second method was reactive compatibilization. The study of blends and their resulting microstructure; their thermal, mechanical, and viscoelastic properties were investigated. The kinetic study of blends compatibilized through both routes was performed. [ABSTRACT FROM PUBLISHER]

As polymers have the ability to be easily molded in to any shape, they have a wide range of applications in industry. Composites prepared by dispersing ceramics in to polymer matrix have higher thermal conductivity than the original polymer, and they still retain their high electrical resistance. In this work, polyvinyl butyral (PVB) is chosen as the polymer matrix. Ceramic nanoparticles like boron nitride (BN), zinc oxide (ZnO) and silicon carbide (SiC) are used as fillers. Polymer composites with different filler loading ratio (wt %) are prepared and their thermal and electrical properties are analyzed. FT–IR, XRD and TGA characterizations are also performed on the composites. The results indicated that PVB composite with hexagonal boron nitride (h–BN) showed the best improvement in thermal conductivity up to 0.5194 W m −1 .K −1 which is an increase of 131.87%, and volume resistivity of composites remained high, above the 10 10 Ω–cm level. [ABSTRACT FROM AUTHOR]

Chemical treatment of natural fibers is a well-defined means of mechanical property improvement in natural fiberreinforced composites. An understanding of mechanical and thermal properties in these media is essential for evaluating heat transfer, thermal degradation, and overall performance of these composites over their product lifetime. However, very little information is available illustrating the effect of such treatment on the thermal properties of kenaf composites. Also, no study to date has reported the thermal conductivity of individual kenaf fibers. This study reports the effects of fiber treatment (in 6% NaOH) on thermal transport in unidirectionally oriented kenaf-epoxy composites and individual kenaf fibers. The effective thermal conductivities and thermal diffusivities of chemically treated fiber composites show a general increase over untreated fiber composites (0.210 to 0.232 W/m/K at 28 oC, 0.206 to 0.234 W/m/K at 200 oC). This improvement may be attributed to improved interfacial contact between the fibers and epoxy matrix shown in microstructural images after chemical treatment. The thermal conductivity of individual fibers was evaluated at room temperature using two techniques. Results from both techniques showed slight increases after chemical treatment (0.58±0.53 to 1.0±0.13 W/m/K and 1.2±0.54 to 1.6±0.28 W/m/K) but lacked statistical significance. Any improvement in surface crystallinity after chemical treatment does not appear to affect overall fiber thermal conductivity. A better understanding of thermal transport in kenaf fibers and composites enables better estimation of the performance of these composites in different applications. Moreover, the thermal conductivities of individual fibers are useful in understanding the fiber's contribution to conduction in different fiber reinforcement configurations. [ABSTRACT FROM AUTHOR]

Thermoelectric technology has revealed the potential for automotive exhaust-based thermoelectric generator (TEG), which contributes to the improvement of the fuel economy of the engine-powered vehicle. As a major factor, thermal capacity and heat transfer of the heat exchanger affect the performance of TEG effectively. With the thermal energy of exhaust gas harvested by thermoelectric modules, a temperature gradient appears on the heat exchanger surface, so as the interior flow distribution of the heat exchanger. In order to achieve uniform temperature distribution and higher interface temperature, the thermal characteristics of heat exchangers with various heat transfer enhancement features are studied, such as internal structure, material and surface area. Combining the computational fluid dynamics simulations and infrared test on a high-performance engine with a dynamometer, the thermal performance of the heat exchanger is evaluated. Simulation and experiment results show that a plate-shaped heat exchanger made of brass with accordion-shaped internal structure achieves a relatively ideal performance, which can practically improve overall thermal performance of the TEG.

Thermal transient testing is widely used for LED characterization, derivation of compact models, and calibration of 3D finite element models. The traditional analysis of transient thermal measurements yields a thermal model for a single heat source. However, it appears that secondary heat sources are typically present in LED packages and significantly limit the model’s precision. In this paper, we reveal inaccuracies of thermal transient measurements interpretation associated with the secondary heat sources related to the light trapped in an optical encapsulant and phosphor light conversion losses. We show that both have a significant impact on the transient response for mid-power LED packages. We present a novel methodology of a derivation and calibration of thermal models for LEDs with multiple heat sources. It can be applied not only to monochromatic LEDs but particularly also to LEDs with phosphor light conversion. The methodology enables a separate characterization of the primary pn junction thermal power source and the secondary heat sources in an LED package.

A laser ultrasonics approach to remotely characterize the elastic and thermal properties of a coating-substrate structure, used to protect fuel claddings in lead-bismuth eutectic cooled nuclear reactors, is presented and validated with experimental results. A transient grating geometry is used for multiple wavelength excitation of thermoelastic displacements, and laser beam deflection for detection. The value of Young’s modulus of the coating layer as calculated from the coating’s Rayleigh velocity of 190 ± 50 GPa is in accordance with a nano-indentation measurement. Using a priori knowledge concerning the density and elastic parameters of the coating and substrate, scanning the sample allows the obtaining of a coating thickness map in a fully remote, all-optical way, with an accuracy of about 4 microns for a coating of around 20-micron average thickness. Analyzing the transient thermal grating decay yields a thermal diffusivity value of ( 5.0 ± 1.6 ) × 10 − 6 m 2 /s, in the range of low-carbon steels. The consistency of the results infers that the all-optical laser ultrasonics approach should be feasible for remote inspection of the quality of optically rough coated claddings in the harsh environment of a nuclear reactor.

During the last twenty years DBD plasma actuators have been known by their ability for boundary layer flow control applications. However, their usefulness is not limited to this application field, they also present great utility for applications within the field of heat transfer, such as a way to improve the aerodynamic efficiency of film cooling of gas turbine blades, or de-icing and ice formation prevention. Nevertheless, there is a relative lack of information about DBD’s thermal characteristics and its heat generation mechanisms. This happens due to the extremely high electric fields in the plasma region and consequent impossibility of applying intrusive measurement techniques. Against this background, this work describes the physical mechanisms behind the generation of heat associated to the DBD plasma actuators operation. An experimental technique, based on calorimetric principles, was devised in order to quantify the heat energy generated during the plasma actuators operation. The influence of the dielectric thickness, as well as the dielectric material, were also evaluated during this work. The results were exposed and discussed with the purpose of a better understanding of the heat generation mechanisms behind the operation of DBD plasma actuators. [ABSTRACT FROM AUTHOR]

Polymorphic transformation in Trimethoprim (TMP) drug has been studied employing differential scanning calorimetry (DSC), TG/DSC, X-ray diffraction and FTIR techniques. To obtain a better understanding of the thermal events for the TMP polymorphs, a series of increasing heating rates and different mass were used. DSC of the Trimethoprim indicated that the as-received sample was crystalline (Form A). The molten Trimethoprim on cooling, however, produced a glassy amorphous mass. The sample obtained after heating at 100 °C for 1 h transformed to Trimethoprim (Form B).The glass transition observed in the second heating at 61 °C was followed by crystallization of the product at 81 °C. Form B of this study is probably a novel TMP polymorph. [ABSTRACT FROM AUTHOR]

This paper presents a thermal characterization of salt mixtures applying the T-History method (THM) and the differential scanning calorimetry (DSC) techniques. By using water as a standard substance, the original THM was developed to analyze materials with melting points under 100°C. This is the first research that proposes to replace water by glycerin to characterize medium-melting-temperature phase-change materials (PCMs) (140–220°C). Moreover, the DSC technique was used to validate and compare the results obtained with the THM for each mixture. For instance, the system compound of 40% KNO3–60% NaNO3 was studied, and the enthalpy of fusion determined by THM and DSC differs by 2.1% between each method. The results given by the two methods for all mixtures showed that both techniques are complementary and present satisfactory agreement with the specialized literature. [ABSTRACT FROM AUTHOR]

Deinking paper sludge (DPS)/high density polyethylene (HDPE) composites with and without coupling agent (3 % of maleated polyethylene (MAPE)) were manufactured by twin-screw extrusion followed by injection molding with high percentages of DPS (0, 20, 30 and 40 %). The effects of DPS content and MAPE on the mechanical, thermal, and morphological properties of the DPS/HDPE composites were investigated. Increasing DPS content in composites increased the tensile and flexural modulus (E; MOE), tensile and flexural strength (Rm; MOR), while decreased elongation at break and Un-notched impact resistance due to a poor adhesion between the DPS and HDPE. The addition of DPS also improved the thermal stability and increased the composites crystallinity. High content of DPS (40 %) and 3 % MAPE achieved good interfacial adhesion between fibres of DPS and HDPE. Therefore, an increase is observed for Rm, MOR, ductility, and impact toughness. [ABSTRACT FROM AUTHOR]

Characterization of the thermal properties of the surface and subsurface structures of the skin can reveal the degree of hydration, the rate of blood flow in near-surface micro- and macrovasculature, and other important physiological information of relevance to dermatological and overall health status. Here, a soft, stretchable thermal sensor, based on the so-called three omega (i.e., 3ω) method, is introduced for accurate characterization of the thermal conductivity and diffusivity of materials systems, such as the skin, which can be challenging to measure using established techniques. Experiments on skin at different body locations and under different physical states demonstrate the possibilities. Systematic studies establish the underlying principles of operation in these unusual systems, thereby allowing rational design and use, through combined investigations based on analytical modeling, experimental measurements, and finite element analysis. The findings create broad opportunities for 3ω methods in biology, with utility ranging from the integration with surgical tools or implantable devices to noninvasive uses in clinical diagnostics and therapeutics. [ABSTRACT FROM AUTHOR]

In this work, thermal properties of composites from chicken feather fiber (CFF) and polylactic acid (PLA) were investigated. CFF/PLA green composites were manufactured by extrusion and injection molding. Short and long fibers (3 and 20 mm) were used at different contents (2, 5 and 10 mass%). The effects of fiber concentration and fiber length on thermal properties of CFF/PLA composites were studied. Thermal properties of CFF/PLA composites were examined through differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and dynamic mechanical analysis (DMA). From the experiments, it was found that addition of CFF was effective to improve the thermal properties of PLA. The DSC results showed that heat flow increased with the increase in CFF content on the glass transition, on the crystallization temperature and on melting temperature. The TG results revealed that addition of CFF to PLA had positive effect on the thermal stability. In addition, the results of DMA experiments showed that the tan δ decreased with the increasing CFF content, indicating less damping and more elastic behavior in the composites. The results obtained from this study provide important information on the temperature-dependent properties of CFF/PLA and lead to new product development based on natural resources. [ABSTRACT FROM AUTHOR]

Advances in nano-electronics, nano-optics, energy harvesting materials, and nanoparticle-based photothermal therapies are motivating studies of the thermal properties of micro/nanostructures. Thus, the demands for highly sensitive and accurate thermal measurement techniques are encouraged for both fundamental studies and industrial applications. The time-domain thermoreflectance (TDTR) method, based on an ultrafast pump-probe technique, enables high-fidelity thermal measurements at the micro/nanoscale and the observation of dynamic processes with sub-picosecond time resolution. TDTR is an optical technique, capable of measuring the thermal properties of micro/nanostructures, including thermal conductivity and interfacial thermal conductance of bulk substrates, thin films, and nanoparticles, among others. Here we review some recent developments in the state-of-the-art ultrafast pump-probe method applied to study the thermal and magnetic properties of materials at the micro- and nanometer scales. We also discuss in detail improvements to this technique by presenting several example extensions to its capabilities. [ABSTRACT FROM AUTHOR]

Thermal conductivity, thermal diffusivity, and volumetric heat capacity of three spider silks are measured in this paper as a benchmark for further studies. These silks include the major and minor ampullate silks of the Nephila clavipes spider, and a synthetic spider silk fiber made from recombinant dragline silk proteins purified from transgenic goats' milk. Two complementary measurement techniques are employed in the thermal characterization of these microscale single fibers for self-verification. One is the transient electrothermal technique (TET) and the other is the 3ω method. Experimental measurements indicate that thermal properties of the dragline silk are very close to those of the minor ampullate silk, whereas the ones for the synthetic silk are much lower due in part to its low crystallinity. The directly measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of the major and minor ampullate silks are 1.2–1.26 W m − 1 K − 1 , 5.7–6 × 10 − 7 m 2 s − 1 , and 2–2.17 MJm − 3 K − 1 , respectively. The thermal conductivity and thermal diffusivity of the as-spun synthetic silk are 0.24 W m − 1 K − 1 and 1.6 × 10 − 7 m 2 s − 1 respectively. As part of this study, a detailed comparison of the TET and 3ω methods is provided showing the complementary nature of the techniques and illustrating the strengths and weaknesses of each. [ABSTRACT FROM AUTHOR]

The water-processable microfibrillated cellulose (MFC) and sodium lignosulfonate (NaLS) system was used for the first time as carbon precursor. After drying and one-step pyrolysis up to 800 °C, the resulting bio carbonaceous char can acquire considerable electrical conductivity and porosity, making it a promising electrode material in energy storage devices. The present work characterizes MFC and NaLS separately as well as in blends in terms of morphology (SEM), structure (FTIR) and thermal stability (TG–MS). DTG patterns illustrate that MFC degrades in a narrow temperature range but at high reaction rates, whereas NaLS reacts more steadily in a larger temperature range. The thermal degradation rate of a MFC/NaLS blend differs from an additive weighted thermal degradation rate of each component: MFC and NaLS. The presence of sodium in the blends induced catalytic effects and made MFC decomposition to shift toward lower temperatures. This observation could be kinetically interpreted as a decrease of the MFC thermal degradation activation energies in the composites. The kinetics of MFC/NaLS blends is investigated by both model-free and mode-based methods, with the latter providing more appropriate Arrhenius parameters that allow reproducing the experimental curves. [ABSTRACT FROM AUTHOR]

An 8-pixel X-ray diamond detector prototype, fabricated on an alumina substrate and specifically designed to operate at high temperature, has been developed and tested. Tungsten electrodes were developed as metal-semiconductor contact and showed an ohmic behavior, as inferred from current-voltage measurements. A 40-cycles thermal stress test performed in helium atmosphere, in which temperature has been varied cyclically between 100 and 240 °C, showed minor evolution of the detector dark current, presumably related to progressive water desorption from the alumina substrate. Conversely, X-ray photocurrent measurements showed no significant differences before and after the thermal cycles, confirming no degradation of the stability of the prototype even after prolonged operation at high temperature. [Display omitted] • A diamond X-ray detector prototype has been tested at high temperature (~240 °C). • Thermal tests (T = 100÷240 °C) in helium showed minor evolution of the dark current. • Photocurrent measurements confirm no loss in terms of X-ray detection. [ABSTRACT FROM AUTHOR]

Bio-based epoxy thermoset resins have been developed from epoxidized soybean oil (ESO) cured with tannic acid (TA). These two substances of vegetable origin have been gathering attention due to their accessibility, favorable economic conditions, and convenient chemical functionalization. TA's suitable high phenolic functionalization has been used to crosslink ESO by adjusting the -OH (from TA):epoxy (from ESO) molar ratio from 0.5:1 to 2.5:1. By means of Fourier-transform infrared spectroscopy, resulting in thermosets that evidenced optimal curing properties under moderate conditions (150-160 °C). The thermogravimetric analysis of the cured resins showed thermal stability up to 261 °C, with modulable mechanical and thermal properties determined by differential scanning calorimetry, dynamical mechanical thermal analysis, and tensile testing. Water contact angle measurements (83-87°) and water absorption tests (0.6-4.5 initial weight% intake) were performed to assess the suitability of the resins as waterproof coatings. Electrochemical impedance spectroscopy measurements were performed to characterize the anti-corrosive capability of these coatings on carbon steel substrates. Excellent barrier properties have been demonstrated due to the high electrical isolation and water impermeability of these oil-based coatings, without signs of deterioration over 6 months of immersion in a 3.5 wt.% NaCl solution. These results demonstrate the suitability of the developed materials as anti-corrosion coatings for specific applications.

The paper presents the synthesis and thermal behavior of novel epoxy resins prepared from epoxidized castor oil in the presence of or without trimethylolpropane triglycidyl ether (TMP) crosslinked with 3-hexahydro-4-methylphtalic anhydride (MHHPA) and their comparison with a petroleum-based epoxy resin (MHHPA and TMP). Epoxidized castor oil (ECO) was obtained via in situ epoxidation of castor oil with peroxyacetic acid. The chemical structures of castor oil (CO), ECO, and epoxy matrix were confirmed using FT-IR and 1 H-NMR spectroscopy. The morphological and thermal behavior of the resulting products have been investigated. Compared to petroleum-based resins, castor oil-based ones have a lower T g . Anyway, the introduction of TMP increases the T g of the resins containing ECO. The morphological behavior is not significantly influenced by using ECO or by adding TMP in the synthesis of resins. The dielectric properties of epoxy resins have been analyzed as a function of frequency (1 kHz-1 MHz) and temperature (-50 to 200 °C). The water absorption test showed that as T g increased, the percent mass of water ingress decreased.

We proposed a silicon-based micro calorimeter with a single thermocouple structure for heat detection. Silicon as a material with high Seebeck coefficient is employed to achieve prominent sensitivity using a single thermocouple junction. The suspended bridge structure composed of the device layer of silicon on insulator (SOI), which is one important thermocouple materials, is also fabricated for micro calorimeter by the microelectromechanical system (MEMS) technology to obtain reduced heat loss and achieve high sensitivity and fast response. The fabricated micro calorimeter shows a sensitivity of 0.44 V/W and response time less than 20 ms. The single thermocouple structure allows facile fabrication process and compact structure for portable thermal detection sensor. This proposed silicon-based thermocouple calorimeter with a bridge structure is capable of integrating a silicon sensor into the micro fluidic system for applications in health detection. [ABSTRACT FROM AUTHOR]

ABSTRACT:The study was created using "ANSYS 5.4" the Physical CAD tool to find out the effect of fiber direction on thermal characterization for tow types of the polymer composites. One was the epoxy reinforced with Glass fibers composite (EGF), the other was the Polyester reinforced by the same type of fibers (PGF). The fibers angled with tow angles 00 and 450 with pivot of each type of the composites. The loads and boundary conditions (B.C) was applied as different temperatures. The study included temperature distribution, thermal flux and thermal gradient in which obtained directly from the package. The thermal conductivity withal was calculated from the results. The analysis showed that the temperature distribution is almost constant for all models, the thermal flux was 1743 (J/S.m2) for the EGF composites with 00 and 1494 (J/S.m2) for the 450, thermal gradient was 3134 (K0/m) for 0 0 and 4187 (K0/m) for 45 0. For PGF composites the values of thermal flux was 1799 (J/S.m2) for 00 and 1505 (J/S.m2) for 450, the thermal gradient was 3112 (K0/m) for the 00 and 4187 (K0/m) for 450. Thermal conductivity obtained from the previous results and the highest value was 0.578 (W/K0.m) for PGF 00, followed by 0.556 (W/K0.m) for EGF with the same angle of fibers. Other hand the other composites EGF and PGF with 45 0 had a lower values for thermal conductivity which were both about 0.36 (W/K0.m), for that reason we conclude that the last tow types (with 450 angle) were preferred to use in applications as water tanks or other thermal insulation systems.

Blendas de poliolefinas/HIPS têm sido exploradas para obter filmes especiais com determinadas propriedades desejadas, tornando imperativo desenvolver vários estudos para um melhor conhecimento do comportamento desses materiais. Neste trabalho, efeitos da adição dos copolímeros comerciais de estireno-butadieno multibloco (SBS) e de estireno-(etileno-co-butileno)-estireno (SEBS) tribloco linear em blendas pós-consumo de HDPE e HIPS são reportados. A diminuição nas dimensões da microfase dispersa, aliada à rugosidade superficial da fase HDPE após extração seletiva do HIPS, independentemente de a fase matriz ser HIPS ou HDPE, mostraram mais eficiência do SEBS como modificador interfacial de tensão ou como surfactante entre os diferentes domínios quando comparado com o SBS. Os resultados das caracterizações térmicas, por exemplo, menor Tm e menor grau de cristalinidade do HDPE, e maior Tg do poliestireno na presença de SEBS corroboraram esta conclusão, como será discutido posteriormente.Blending of post-consumer polyolefins/HIPS has been exploited for obtaining special films with a desired set of properties, which has required studies to understand the behavior of these materials. In this work the effects of commercial multiblock styrene-butadiene (SBS) and linear triblock styrene-(ethylene-co-butylene)-styrene (SEBS) copolymers in blends of post-consumer high density polyethylene (HDPE) and HIPS are reported. Thermal properties and phase morphology were comparatively analyzed for the additives aiming at verifying possible correlations between them. Decreased dimensions of the minor micro phase along with HDPE surface roughness after HIPS selective extraction, independently of the matrix being HIPS or HDPE, showed better effectiveness for SEBS as interfacial tension modifier or as surfactant at the different domains interface when compared with SBS. The results of thermal characterizations, e.g. lower HDPE melting temperature, lower degree of crystallinity, and higher polystyrene glass transition temperature in the presence of SEBS corroborated with this conclusion as it will be discussed further.