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Different proportions of polyamidoamine (PAMAM) dendrimer were blended with poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) resin in chloroform for film casting. Differential scanning calorimetry and scanning electron microscopy were employed to characterize the PHBV/PAMAM composite films upon stretching and tangential breaking. The results indicated that with the addition of PAMAM dendrimer, the glass transition temperature of the PHBV/PAMAM composite films became more distinct, indicating that the blends had a greater toughness than pure PHBV. The calculated crystallinity values indicated that the crystallinity of the PHBV/ PAMAM blends was lower than that of PHBV (0.09-56.18 % vs. 73.18 %, respectively). Moreover, the mechanical performance tests indicated that the addition of PAMAM dendrimer considerably increased the tangential breaking strength of PHBV from 24.08 kN/m to as high as 62.03 kN/m, whereas the tensile strength remained basically unchanged. The optimal toughening effect was observed with a PAMAM dendrimer content of 3.0 phr.

Wearable physical activity monitors are growing in popularity and provide the opportunity for large numbers of the public to self-monitor physical activity behaviours. The latest generation of these devices feature multiple sensors, ostensibly similar or even superior to advanced research instruments. However, little is known about the accuracy of their energy expenditure estimates. Here, we assessed their performance against criterion measurements in both controlled laboratory conditions (simulated activities of daily living and structured exercise) and over a 24 hour period in free-living conditions. Thirty men (n = 15) and women (n = 15) wore three multi-sensor consumer monitors (Microsoft Band, Apple Watch and Fitbit Charge HR), an accelerometry-only device as a comparison (Jawbone UP24) and validated research-grade multi-sensor devices (BodyMedia Core and individually calibrated Actiheart™). During discrete laboratory activities when compared against indirect calorimetry, the Apple Watch performed similarly to criterion measures. The Fitbit Charge HR was less consistent at measurement of discrete activities, but produced similar free-living estimates to the Apple Watch. Both these devices underestimated free-living energy expenditure (-394 kcal/d and -405 kcal/d, respectively; P<0.01). The multi-sensor Microsoft Band and accelerometry-only Jawbone UP24 devices underestimated most laboratory activities and substantially underestimated free-living expenditure (-1128 kcal/d and -998 kcal/d, respectively; P<0.01). None of the consumer devices were deemed equivalent to the reference method for daily energy expenditure. For all devices, there was a tendency for negative bias with greater daily energy expenditure. No consumer monitors performed as well as the research-grade devices although in some (but not all) cases, estimates were close to criterion measurements. Thus, whilst industry-led innovation has improved the accuracy of consumer monitors, these devices are not yet equivalent to the best research-grade devices or indeed equivalent to each other. We propose independent quality standards and/or accuracy ratings for consumer devices are required.

Samarium monosulfide, a strain gauge and barometric material, exists in equilibrium with Sm.sub.3S.sub.4 and Sm.sub.2O.sub.2S in the S-Sm-O system. Therefore, studying phase equilibria in the refractory Sm.sub.2S.sub.3-X-SmS-Sm.sub.2O.sub.2S system is a scientifically interesting task. In this system, 49 samples were synthesized and studied by powder XRD, differential scanning calorimetry, visual thermal analysis, and microstructural analysis. Melting points of Sm.sub.3S.sub.4, SmS, and Sm.sub.2O.sub.2S compounds were determined. Eutectic diagrams of Sm.sub.3S.sub.4-Sm.sub.2O.sub.2S, SmS-Sm.sub.2O.sub.2S, SmS-Sm.sub.3S.sub.4 systems were constructed. Temperatures and compositions of the binary eutectic points were determined. Fusion enthalpies for Sm.sub.3S.sub.4, SmS, and Sm.sub.2O.sub.2S phases were estimated using the Schröder-Le Chatelier equation. The liquidus lines were calculated using second-degree polynomials and Redlich-Kister model. Coordinates of the ternary eutectic point in the Sm.sub.3S.sub.4-SmS-Sm.sub.2O.sub.2S system were calculated using the cutting-plane method and the Scheffé method. The calculated compositions of ternary eutectic points were averaged at one most probable point, in accordance with the data on the samples microstructure. The experimental temperature of the ternary eutectic point coincides with the calculated values within the margin of error. Positions of eutectic valleys and approximate positions of isotherms in the system were established. Thermodynamic parameters of the [alpha]-Sm.sub.2S.sub.3 [right arrow] [gamma]-Sm.sub.2S.sub.3 polymorphic transition and the dependence of the Sm.sub.2S.sub.3-X composition on heat treatment conditions were determined. According to the scanning electron microscopy data, the approximate composition of the crystallized from the melt Sm.sub.2S.sub.3 sample is Sm.sub.2S.sub.2.95. The Sm.sub.10S.sub.14O phase decomposes at 1470 ± 15 °C in the course of a solid-phase reaction. The phase diagram of the Sm.sub.2S.sub.3-X-Sm.sub.2O.sub.2S system was revisited. Optical band gaps of Sm.sub.10S.sub.14O and Sm.sub.2O.sub.2S phases were determined. The Sm.sub.10S.sub.14O compound was optically characterized for the first time; its direct and indirect optical bandgaps were found equal to 2.48 and 2.37 eV, respectively. The determined direct and indirect optical bandgaps of Sm.sub.2O.sub.2S (4.4 eV and 3.95 eV, respectively) agree with the earlier measurements, thus confirming the accuracy of the chosen synthesis procedures.

The thermochemical and kinetic studies of the formation of iodine (I.sub.2) and 4-(dimethylamino) pyridine (DMAP) complexes in solution were investigated using microcalorimetry at 25 °C. First, a theoretical approach of the [sigma]-hole bonding leading to these complexes based on the calculation of complexation energy values, Vs.sub.min,max, localization of the molecular orbitals and the amount of charge transfer, was developed. The hexane was chosen as a solvent for both DMAP and I.sub.2 solids. The plots of the complexation heats as a function of r.sub.1 = [DMAP]/[I.sub.2] and r.sub.2 = [I.sub.2]/[DMAP] ratios (where [DMAP] and [I.sub.2] are the concentrations of DMAP and I.sub.2, respectively) show that mixing DMAP solution to I.sub.2 ones or vice versa has the same tendency but do not lead to the same enthalpies and is not a reciprocal phenomenon. For particular r.sub.1 and r.sub.2 values, we can suggest complex forms for the reaction between I.sub.2 and DMAP by taking into account the measured and calculated complexation energies. The kinetic mechanisms and theoretical heat flow equations have been proposed for the lowest and highest r.sub.1 and r.sub.2 ratios. Iterating the heat flow equations while considering the deconvoluted curves allows to deduce the kinetic and thermodynamic parameters as: global order, partial order, rate constant, apparent rate constant and complexation enthalpies: for each mechanism, the latter parameter agrees with both the measured and theoretical ones.

We present an optimized version of the skin calorimeter for measuring localized skin thermal responses during physical activity. Enhancements include a new holding system, more sensitive thermopiles, and an upgraded spiked heat sink for improved efficiency. In addition, we used a new, improved calorimetric model that takes into account all the variables that influence the measurement process. Resolution in power measurement is 1 mW. Performance tests under air currents and movement disturbances showed that the device maintains high accuracy; the deviation produced by these significant disturbances is less than 5%. Human subject tests, both at rest and during exercise, confirmed its ability to accurately measure localized skin heat flux, heat capacity, and thermal resistance (less than 5% uncertainty). These findings highlight the calorimeter’s potential for applications in sports medicine and physiological studies.