Solid-State Heating Using the Multicaloric Effect in Multiferroics

The multicaloric effect is defined as the adiabatic reversible temperature change in multiferroic materials induced by the application of an external electric or magnetic field, and it was first theoretically proposed in 2012. The multicaloric effects in multiferroics, as well as other similar caloric effects in single ferroics, such as magnetocaloric, elastocaloric, barocaloric, and electrocaloric, have been the focus of much research due to their potential commercialization in solid-state refrigeration. In this short communication article, we examine the thermodynamics of the multicaloric effect for solid-state heating applications. A possible thermodynamic multicaloric heating cycle is proposed and then implemented to estimate the solid-state heating effect for a known electrocaloric system. This work offers a path to implementing caloric and multicaloric effects to efficient heating systems, and we offer a theoretical estimate of the upper limit of the temperature change achievable in a multicaloric cooling or heating effect.

Synthesis of a fuzzy controller for identification and quantification of disturbances by trends

This article describes the main stages of constructing a fuzzy controller that identifies disturbances in the automatic control system by trends on the example of the brine cycle, namely, heating the purified one going to electrolysis. This method can be implemented in perturbation control systems for the formation of control actions, as well as for diagnostic purposes. The aim of the study is to synthesize a fuzzy controller for identifying and quantifying perturbations by trends. The article proposes a method for estimating perturbations by trends. A mathematical model of processes implemented in the Mathcad environment is constructed. A conceptual model of a fuzzy controller for determining the perturbation is implemented. As a result of the research conducted on the basis of the proposed method, two fuzzy controllers were synthesized that quantify disturbances in the water heating cycle, namely: the deviation of the temperature of the purified brine entering the heat exchanger, as well as the deviation of the water temperature in the tank from the norm. The developed project is of practical importance, since the information about disturbances obtained as an output value from the fuzzy controller can be used in the diagnosis and assessment of the system state at any time, which, in turn, can be used for smoother control when applying a correction signal to the controller that controls the dampers and pumps, as well as to prevent accidents.

The Effects of Select Hydrocolloids on the Processing of Pâté-Style Canned Pet Food

Hydrocolloids are commonly used in canned pet food. However, their functional effects have not been quantified in this food format. The objective was to determine the effects of select hydrocolloids on batter consistency, heat penetration, and texture of canned pet food. Treatments were added to the formula as 1% dextrose (D) and 0.5% guar gum with 0.5% of either dextrose (DG), kappa carrageenan (KCG), locust bean gum (LBG), or xanthan gum (XGG). Data were analyzed as a 1-way ANOVA with batch as a random effect and separated by Fisher’s LSD at p < 0.05. Batter consistency (distance traveled in 30 s) thickened with increasing levels of hydrocolloids (thinnest to thickest: 23.63 to 2.75 cm). The D treatment (12.08 min) accumulated greater lethality during the heating cycle compared to all others (average 9.09 min). The KCG treatment (27.00 N) was the firmest and D and DG (average 8.75 N) the softest with LBG and XGG (average 15.59 N) intermediate. Toughness was similar except D (67 N·mm) was less tough than DG (117 N·mm). The D treatment showed the greatest expressible moisture (49.91%), LBG and XGG the lowest (average 16.54%), and DG and KCG intermediate (average 25.26%). Hydrocolloids influenced heat penetration, likely due to differences in batter consistency, and affected finished product texture.

The Study of Dielectric Behavior and Phase Transition of Mixed Compound of Lead Tantalate Sintered with Silver Oxide with Temperature Variation

The dielectric constant of mixed compound of Lead Tantalate(PbTa2O6) sintered with Silver oxide has been measured between the temperatures 40°C to 300°C using the capacitance bridge model ZENITH M 92A at the frequency of 1000 Hz. During the measurement, it is found that the properly annealed sample have three peaks at the temperature 90°C (ε = 1000), 220°C (ε =800) and 230°C (ε = 623) respectively and a high peak at the temperature of 130°C (ε = 1600) in the heating cycle curve with some intermediate fluctuations. When the variation of dielectric constant was studied in cooling cycle the peak was observed at 240ºC, above and below this temperature, dielectric constant decreases with some intermediate fluctuations showing shows a first order phase transition. The variation in heating cycle is explained on the basis of activated polarization process. When the behavior of compound is studied in cooling cycle, then pronounced hysteresis is found with certain intermediate fluctuations. The cooling cycle curve does not follow heating curve because of the temperature relaxation of the compound. The occurrence of peak at the Curie temperature is explained by the latent heat type properties of the mixed compound. The temperature variation of the mixed compound suggests for its valuable applications as active and smart materials and its applications in the ceramics.

Conductive Biomass Films Containing Graphene Oxide and Cationic Cellulose Nanofibers for Electric-Heating Applications

A low-voltage biomass matrix and flexible electric-heating composite with graphene oxide (GO) and cationic cellulose nanofiber (CCNF) were fabricated by ultrasonic dispersion and suction filtration. The main results show that the tensile strength and strain of the films decreased with an increase in the GO content, but the thermal stability increased. The GO/CCNF film underwent rapid thermal decomposition at 250–350 °C, and the maximum degradation temperature was higher by 19 °C compared to that of the pure CCNF film. It was found that the electrical conductivity increased from 0.013 to 2.96 S/cm with an increase in the GO content from 20 to 60 wt%, resulting in an increase in the power density from 122 to 2456 W/m2. The films could rapidly attain the temperature within 50 s, and the heat transferred by radiation and convection was 21.62 mW/°C, thereby exhibiting excellent electric heating response. Moreover, the film demonstrated a stable electric-heating cycle after a 12.5 h cycling test and meets the requirements of low-temperature electric heating products under the 36 V electric safety limit, which expands the potential applications of biomass-derived cellulose nanofibers.

A new weathering indicator from high-temperature magnetic susceptibility measurements in an Argon atmosphere

SUMMARY Environmental magnetism has become more and more popular because it is inexpensive, rapid and non-destructive. However, the environmental implication of traditional magnetic parameters is changed as the weathering intensity is contrasting. For example, magnetic susceptibility cannot be used as pedogenic index for strongly weathered red soils. Thermal magnetic measurement is a common way to identify magnetic minerals in rocks and sediments. Susceptibility enhancement after a 700 °C heating cycle in an argon atmosphere usually happened for various rocks and sediments. The increase is caused by formation of new magnetite from iron derived from paramagnetic iron-containing minerals. This is similar to pedogenesis or weathering process. The heating process in lab released the residual iron in weatherable iron-containing silicates which has not yet been depleted by contemporary pedogenesis or weathering. This residual iron can be quantified by the amount of susceptibility increase after a heating cycle. A negative correlation between the susceptibility increase after heating and the weathering intensity has been found in high-temperature magnetic susceptibility measurements of several sequences located in different climate zones. Results suggest that the degree of weathering can be estimated for intensely weathered red soils as well as for scarcely weathered loess using the amount of susceptibility change after a 700 °C heating cycle. This study provides new perspectives for developing new weathering and pedoclimate proxies using environmental magnetism.

Vibrational Dynamics of Carbamazepine: Studies Based on Two-Dimensional Correlation Spectroscopy and X-ray Diffraction

Fourier transform infrared spectroscopy as well as X-ray diffraction (XRD) were employed to thoroughly study phase transitions taking place during heating–cooling–heating cycle of carbamazepine (CBZ), a well known and commonly used antiepileptic drug. Both techniques revealed cold crystallization taking place during second heating. Moreover, XRD studies for the first time proved the coexistence of CBZ (form I) and iminostilbene (product of the degradation of CBZ) after a heating–cooling cycle. Moving window two-dimensional correlation (MW 2D-COS) spectroscopy and two-dimensional correlation spectroscopy were shown to be effective tools to reveal phase sequences and to provide information about the order of sequential changes of bands’ intensities during each phase transition, respectively.