Battery-Free Shape Memory Alloy Antennas for Detection and Recording of Peak Temperature Activity

Economical sensing and recording of temperatures are important for monitoring the supply chain. Existing approaches measure the entire temperature profile over time using electronic devices running on a battery. This paper presents a simple, intelligent, battery-free solution for capturing key temperature events using the natural thermo-mechanical state of a Shape Memory Alloy (SMA). This approach utilizes the temperature-induced irreversible mechanical deformation of the SMA as a natural way to capture the temperature history without the need for electronic data logging. In this article, two-way SMA is used to record both high-temperature and low-temperature peak events. Precise thermo-mechanically trained SMA are employed as arms of the dipole antenna for Radio Frequency (RF) readout. The fabricated antenna sensor works at 1 GHz and achieves a sensitivity of 0.24 dB/°C and −0.16 dB/°C for recording temperature maxima and minima, respectively.

Thermal Properties and Structural Features of Multilayer Films Based on Chitosan and Anionic Polysaccharides

This study investigates the thermal and structural properties of multilayer composites based on chitosan (CS) and polyanions with different functionalities, including sodium sulfoethyl cellulose (SEC), sodium alginate (ALG), and sodium hyaluronate (HA). Unlike polyelectrolyte complexes (PECs) obtained by polymer mixing, the formation of a PEC layer by a process of layer-by-layer deposition of oppositely charged polymers is accompanied by the transformation of the CS polymorphic state, and this affects the relaxation and thermal properties of the resulting multilayer composite. X-ray diffraction analysis showed that the formation of the PEC layer in the CS/SEC multilayer film is accompanied by crystallization of the CS chains and the formation of a predominantly anhydrous CS modification. Thermogravimetric analysis of the CS/SEC film registers a high-temperature peak associated with the thermal decomposition of crystalline CS in the PEC composition. According to the dynamic mechanical analysis, the CS/SEC composite was characterized by a single glass transition temperature, indicating a strong interaction between the layers when using SEC (a strong acid salt) as the counterion to CS. For multilayer composites with weak polyacid salts (ALG and HA), the crystallization of CS in the PEC layer is weaker, as reflected in the thermal degradation of these films. A high-temperature peak is recorded in the thermal decomposition of CS/HA and is absent in the case of CS/ALG. Dynamic mechanical analysis of the CS/ALG composite showed two glass transition temperatures close to those of the original polymers, indicating weak PEC formation. The CS/HA composite showed an intermediate response. Thus, the effect of the PEC layer on the properties of the poly-layer composites decreases in the order CS/SEC > CS/HA > CS/ALG.

Combustion characteristics of high ash Indian thermal, heat affected coal and their blends

Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields, India. Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable volatile matter required for combustion. In the present work, experimental studies have been carried out to investigate the possible utilization of such heat-affected coal in thermal utilities by blending with other coal. Heat-affected coal (31% ash and 5300 kcal/kg GCV) collected from Jharia coalfield were blended with thermal coal (28% ash and 5650 kcal/kg GCV) in different ratios of 90:10, 80:20, 70:30 and 60:40 to identify the desirable blend ratio for burning of blended coal in thermal utilities. Burning characteristics of all the coals were carried out using TGA. Various combustion parameters such as ignition temperature, peak temperature, burnout temperature, ignition index, burnout index, combustion performance index, rate and heat intensity index of the combustion process and activation energy were evaluated to analyse the combustion process. Experimental and theoretical analysis shows the blend ratio of 90:10 can be used in place of only thermal coal in utilities to reduce the fuel cost.

A terrestrial temperature peak in the first millennia after the Cretaceous-Paleogene Boundary

<p>The Cretaceous-Paleogene (K-Pg) boundary marks one of the five major mass extinctions of the Phanerozoic. A bolide impact and flood basalt volcanism compete as triggers for the extinction, but their relative roles remain contentious. This is in part related to a paucity of robust measurements of temperature change at millennial time scales across the K-Pg boundary. Using the distribution of branched tetraether lipids in samples collected from coals (fossil peats), we present the initial findings of an ongoing study attempting to reconstruct temperatures across North America in the latest Cretaceous to earliest Paleogene. The glycerol dialkyl glycerol tetraether (brGDGTs) palaeotemperature proxy – which has been successfully applied to temperature reconstructions in the Pleistocene and Holocene – is being applied to a succession of fossil peats (lignites) that span the K-Pg boundary at ten sites from Colorado in the south to the North West Territories in the north. The Iridium anomaly that is synonymous with bolide impact at the K-Pg boundary can be used as a datum to correlate the coals. Data derived from coals deposited at a latitude of ~55 °N in Saskatchewan (Canada), are interpreted to reveal millennial-scale records of terrestrial mean annual air temperature (MAAT) for an interval spanning the latest Maastrichtian and earliest Paleogene. The MAAT record peaks at 28 °C ~1 ka (+ 4 ka/- 0.3 ka) after the K-Pg boundary, and subsequently recovers to pre-event values in the subsequent ~ 5 ka (+30 ka/-2 ka). Our unique record is consistent with an abrupt increase in atmospheric CO2 that has been widely documented at this time. </p>

Optimization of Reaction Conditions for Hydroxypropylation of Saba Banana Starch

The aim of this study was to investigate the effects of three reaction variables on the hydroxypropylation of Saba banana (Musa acuminata x Musa balbisiana) starch. The variables were reaction pH (10, 11 and 12), amount of propylene oxide (5, 10 and 15% v/w) and reaction temperature (35, 40 and 45 oC). Response Surface Methodology (RSM) using Central Composite Design was employed to explore the effects of these three variables on the Molar Substitution (MS), pasting properties, freeze-thaw stability and thermal properties of the modified starch. Increasing the amount of propylene oxide, pH and temperature promoted higher level of substitution. All three factors were found significantly (p < 0.05) influenced the MS. These factors also affected the pasting temperature, peak viscosity, breakdown, setback and freeze-thaw stability of the starch pastes. The experimental factors only affected the onset temperature, peak temperature and gelatinization enthalpy of modified starches. In general, propylene oxide exerted the most pronounced effect on hydroxypropylation of Saba banana starch as compared to the reaction pH and temperature. The optimal reaction conditions for hydroxypropylation of Saba banana starch was successfully optimized and validated.

Development of a Fire-Extinguishing Wallpaper Containing Microcapsules

In this study, a wallpaper with fire-extinguishing properties was developed. This wallpaper is expected to increase the evacuation time and suppress the spread of flames in case of fire. It was confirmed that the fire-extinguishing time of an ordinary wallpaper can be increased from 2 to 5 min by incorporating micro-extinguishing capsules in the general water pool. After attaching microfire-extinguishing capsules in the form of a film on the back of the wallpaper, a burning test using a torch and 45° flame retardant digestion was performed, and the thermal properties of the adhesive film were verified based on the reaction start temperature, peak point, reaction end temperature, and weight reduction rate through thermogravimetric analysis.

Evaluation of the FLake Model in ERA5 for Lake Champlain

Global model reanalyses of temperature and radiation are used for many purposes because of their spatial and temporal homogeneity. However, they use sub-models for lakes that are smaller than the model grid. This paper compares the simplified small-lake model, known as FLake, used in the European Centre global reanalysis known as ERA5, with observations made in and near Lake Champlain in northern Vermont. Lake Champlain is a challenging test for the ERA5 FLake model. The lake, which extends over several grid cells, is the lowest region at 30 m above sea level within complex mountain topography. The smoothing of the adjacent mountain topography means that the ERA5 grid cells containing the lake have higher mean elevations then 30 m, and this contributes to a small cool bias in FLake mid-summer temperatures. The seasonal cycle of FLake temperatures has a sharper peak than the observed lake temperatures. In winter, lake temperatures are close to 3°C, while the 30 m deep FLake mixed layer (ML) is near freezing. In May and June, FLake maintains a deep ML, while lake profiles are generally strongly stratified with peak temperatures near the surface several degrees above the model ML. One possible contributing reason is that inflowing river temperatures that are not considered by FLake are as much as 5°C above the lake surface temperature from April to June. The lake does develop a ML structure as it cools from the temperature peak in August, but the FLake ML cools faster and grows deeper in fall. We conclude that the vertical mixing in the FLake ML is stronger than the vertical mixing in Lake Champlain.

Non-contact monitoring of the depth temperature profile for medical laser scanning technologies

Medical treatments such as high-intensity focused ultrasound, hyperthermic laser lipolysis or radiofrequency are employed as a minimally invasive alternatives for targeted tissue therapies. The increased temperature of the tissue triggers various thermal effects and leads to an unavoidable damage. As targeted tissues are generally located below the surface, various approaches are utilized to prevent skin layers from overheating and irreparable thermal damages. These procedures are often accompanied by cooling systems and protective layers accounting for a non-trivial detection of the subsurface temperature peak. Here, we show a temperature peak estimation method based on infrared thermography recording of the surface temperature evolution coupled with a thermal-diffusion-based model and a time-dependent data matching algorithm. The performance of the newly developed method was further showcased by employing hyperthermic laser lipolysis on an ex-vivo porcine fat tissue. Deviations of the estimated peak temperature remained below 1 °C, as validated by simultaneous measurement of depth temperature field within the tissue. Reconstruction of the depth profile shows a good reproducibility of the real temperature distribution with a small deviation of the peak temperature position. A thermal camera in combination with the time-dependent matching bears the scope for non-contact monitoring of the depth temperature profile as fast as 30 s. The latest demand for miniaturization of thermal cameras provides the possibility to embed the model in portable thermal scanners or medical laser technologies for improving safety and efficiency.

Prograde and retrograde P–T evolution of a Variscan high-temperature eclogite, French Massif Central, Haut-Allier

The P–T evolution of a mafic eclogite sample from the Haut-Allier was studied in order to constrain the dynamic of the Variscan subduction in the eastern French Massif Central. Three successive metamorphic stages M1, M2 and M3, are characterized by assemblages comprising garnet1-omphacite-kyanite, garnet2-plagioclase, and amphibole-plagioclase, respectively, and define a clockwise P–T path. These events occurred at the conditions of eclogite (M1; ∼ 20 kbar, 650 °C to ∼ 22.5 kbar, 850 °C), high-pressure granulite (M2; 19.5 kbar and 875 °C) and high-temperature amphibolite facies (M3; < 9 kbar, 750–850 °C), respectively. Pseudosection modelling of garnet growth zoning and mineralogy of the inclusions reveal a prograde M1 stage, first dominated by burial and then by near isobaric heating. Subsequent garnet1 resorption, prior to a renewed growth of garnet2 is interpreted in terms of a decompression during M2. High-pressure partial melting is predicted for both the M1 temperature peak and M2. M3 testifies to further strong decompression associated with limited cooling. The preservation of garnet growth zoning indicates the short-lived character of the temperature increase, decompression and cooling cycle. We argue that such P–T evolution is compatible with the juxtaposition of the asthenosphere against the subducted crust prior to exhumation driven by slab rollback.