Search

Most of the ferromagnetic shape memory (FSM) Heusler alloys, which are primarily studied in bulk form in the literature, exhibit p-d type hybridization. This study conducts a thorough multidirectional investigation of a strongly d-d hybridized quinary melt-spun annealed ribbon having the composition Ni35Mn34.5Co14Fe1Ti15.5 (NMCFT-1). This off-stoichiometric, polycrystalline FSM, fabricated using the melt-spin technique, exhibits a highly textured microstructure, double magnetic transitions and super-mechanical features mitigating brittleness. It crystallizes in a perfectly B2-type disorder austenite (Pm-3m, space group number 221) phase at room temperature. It has been hypothesized that geometric frustration is the causative factor for this disorder. Curie temperature of austenite phase ( T C A ) between paramagnetic → ferromagnetic state is found to be ∼364.57 K, whereas martensite transformation temperature from weak magnetic martensite state to ferromagnetic austenite state is ∼174.74 K. Calculated moments (effective moment, μ eff = 5.12 μ B ; low-temperature saturation moment, μ S (or M S (0) ) = 5.08 μ B ) yield a Rhodes–Wohlfarth ratio of ∼1, indicating the existence of the non-itinerant nature of 3d electrons, whereas the ferromagnetism and the linear or non-linear dependency of M s 2 (T ) on T 2 around T C A indicates the presence of long-range Rudermann–Kittel–Kasuya–Yosida-type interaction. More importantly, the maximum magnetic entropy change ( Δ S m ) obtained across the first-order magneto-structural transition and second-order magnetic transition are +18.2 J·kg−1K−1 at 6 T and −8.8 J·kg−1K−1 at 2 T, respectively, while a very high working temperature span (Δ T FWHM) of 28.561 K and 6.922 K are found for the same condition. The sample exhibits a significant relative cooling power of 402.98 J·kg−1 at a magnetic field of 6 T across the FOMT and 60.19 J·kg−1 at a 2 T field across the SOMT, respectively, along with excellent mechanical features such as a Vickers hardness (HV) of 411.80 HV (∼4.04 GPa). Meanwhile, Chen's super hard model fails to predict the ribbon's HV value, but Miao's hard model does, indicating that the ribbon is hard but not super hard. It also paves the way for additional investigation into innovative FSMs like this. [ABSTRACT FROM AUTHOR]

Investigating the thermal hysteresis and its effect on the kinetic behaviors and reaction model of vacuum residue pyrolysis is of significant importance in industry and scientific research. Effects of heating rate and heating transfer resistance on the pyrolysis process were examined with the thermogravimetric analysis. The kinetic characteristics of the vacuum residue pyrolysis were estimated using the iso-conversional method and integral master-plots method based on a three-stage reaction model through the deconvolution of Fraser-Suzuki function. Results showed that the reaction order models for the first and second stages were associated with the evaporation of vapor, while the nucleation and growth models for the third stage were linked to char formation. During the pyrolysis, the thermal hysteresis led to an increase in the reaction order in the first stage, which resulted in a delayed release of generated hydrocarbons due to high heating rate and enhanced heat transfer resistance. The reaction in the last stage primarily involved coking, where the presence of an inert solid acted as a nucleating agent, facilitating char formation and reducing the activation energy. The optimization results suggest that the obtained three-stage reaction model and kinetic triplets have the potential to effectively describe the active pyrolysis behavior of vacuum residue under high thermal hysteresis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geodesy & Geodynamics (1671-5942) is the property of Editorial Board Journal of Geodesy & Geodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The thermodynamic and kinetic simulations based on the re-assessment of the thermodynamic and kinetic database of the Ni-Ti-Cu system were employed to predict the phenomena of mechanical alloying, spark plasma sintering and thermal properties of the intriguing Ni-Ti-Cu system. Thermodynamic calculations are presented for the stable and unstable phases of NiTiCu materials and support a correlation with the evolving microstructure during the technological process. Also, the thermal conductivity, the thermal diffusivity and the specific heat of spark plasma sintered and aged Cu-alloyed NiTi-based shape memory alloys (NiTiCu) with two compositions, Ni45Ti50Cu5 and Ni40Ti50Cu10, are evaluated and the influence of mechanical alloying and precipitates on thermal properties is discussed. Measurements of these thermal properties were carried out from 25 °C up to 175 °C using the laser flash method, as well as differential scanning calorimetry. The thermal hysteresis of the 20 mm diameter samples was between 8.8 and 24.5 °C. The observed T0 temperatures from DSC experimental transformation features are in reasonable accordance with the thermodynamic predictions. The determined k values are between 20.04 and 26.87 W/m K and in agreement with the literature results. Moreover, this paper can provide some suggestions for the preparation of NiTiCu shape memory alloys and their applications. [ABSTRACT FROM AUTHOR]

Highlights: Cryopreservation generates ice recrystallization. D. antarctica apoplastic proteins show antifreeze activity. PMI of S. salar sperm can be maintained with AFPs. High MMP of sperm increases with AFPs. D. antarctica apoplastic proteins act as nonpermeable cryoprotectants. Antifreeze proteins (AFPs) are natural biomolecules found in cold-adapted organisms that lower the freezing point of water, allowing survival in icy conditions. These proteins have the potential to improve cryopreservation techniques by enhancing the quality of genetic material postthaw. Deschampsia antarctica, a freezing-tolerant plant, possesses AFPs and is a promising candidate for cryopreservation applications. In this study, we investigated the cryoprotective properties of AFPs from D. antarctica extracts on Atlantic salmon spermatozoa. Apoplastic extracts were used to determine ice recrystallization inhibition (IRI), thermal hysteresis (TH) activities and ice crystal morphology. Spermatozoa were cryopreserved using a standard cryoprotectant medium (C+) and three alternative media supplemented with apoplastic extracts. Flow cytometry was employed to measure plasma membrane integrity (PMI) and mitochondrial membrane potential (MMP) postthaw. Results showed that a low concentration of AFPs (0.05 mg/mL) provided significant IRI activity. Apoplastic extracts from D. antarctica demonstrated a cryoprotective effect on salmon spermatozoa, with PMI comparable to the standard medium. Moreover, samples treated with apoplastic extracts exhibited a higher percentage of cells with high MMP. These findings represent the first and preliminary report that suggests that AFPs derived from apoplastic extracts of D. antarctica have the potential to serve as cryoprotectants and could allow the development of novel freezing media. [ABSTRACT FROM AUTHOR]

Temperature‐modulated colloidal phase of plasmonic nanoparticles is a convenient playground for resettable soft‐actuators or colorimetric sensors. To render reversible clustering under temperature change, bulky ligands are required, especially if anisotropic morphologies are of interest. This study showcases thermoresponsive gold nanorods by employing small surface ligands, bis (p‐sulfonatophenyl) phenyl‐phosphine dihydrate dipotassium salt (BSPP) and native cationic surfactant. Temperature‐dependent analysis in real‐time allowed to describe the structural features (interparticle distance and cluster size) as well as thermal parameters, melting and freezing temperatures. These findings suggest that neither covalent Au−S bonds nor bulky ligands are required to obtain a robust thermoresponsive system based on anisotropic gold nanoparticles, paving the way to stimuli‐responsive nanoparticles with a wide range of sizes and geometries. [ABSTRACT FROM AUTHOR]

We measured the temperature dependence of the resistance in thinned samples of a layered transition metal dichalcogenide 1T-TiSe2. As a result, a thermal hysteresis of resistance was discovered in most samples with a thickness of 10 μm or less, but not in samples thicker than 100 μm. The onset temperature of this hysteresis was almost the same as the onset temperature of the charge density wave (CDW) transition, suggesting that this hysteresis is related to the CDW. All the samples with hysteresis exhibited one or a few jumps of resistance in the 110–190 K range in cooling. Moreover, the hysteresis was related not only to the history of temperature below the CDW transition temperature, but also to that above the transition temperature. To interpret these anomalous results, we discuss the effect of impurities on the domain structure of the CDW. [ABSTRACT FROM AUTHOR]

This research paper presents the results and analysis obtained via the evaluation of calcium nitrate as an effective stabilizer to alter the thermal properties as well as improve the compressive strength of frost-susceptible soil. Two silty sand soils with 15% and 25% fines content that are categorized as high to very high frost-susceptible soil were considered and treated with varying dosages of calcium nitrate contents (1.5%, 3.0%, 4.5%, 10%, 15%, and 20% of soil weight). The thermal properties, including thermal hysteresis, thermal conductivity, specific heat capacity, freezing point depression, and phase changes (freezing and thawing point) were determined for the untreated and treated soil samples. It was observed that the treated samples' thermal properties were significantly altered with respect to untreated soils. The effects of fines content on the thermal properties were evaluated using a stabilizer–silt content ratio. The threshold calcium nitrate dosage content was established, and a new correlation was established to evaluate the freezing point and thawing point. The unconfined compressive strength (UCS) tests performed on the treated soils depicted a significant increase in compressive strength compared to the untreated soil. Further analysis showed that fines content has a significant role to play on the compressive strength of treated silty sand. A qualitative analysis performed on images from a scanning electron microscope (SEM) showed that increasing the calcium nitrate dosage reduced the pore size and improved the cementation between the sand and silt grains. [ABSTRACT FROM AUTHOR]

Dehydrins exist widely in plants and play an important role in abiotic stress resistance. Two low-temperature-induced dehydrin-like genes, PmCAP and LpCAP, from the pine species Pseudotsuga menziesii and Larix principis-rupprechtii Mayr were cloned and found to contain 576 bp and 687 bp, encoding 191 and 228 amino acids, respectively. Both genes were individually assembled into prokaryotic expression vectors and transferred into E. coli cells. When transgenic stains were cultured at −5 °C, the lethal time 50% (LT50) was 50 h and 54 h for PmCAP and LpCAP, respectively, compared with 32 h for the control. When cultured at −20 °C, the LT50 was 38 h, 41 h, and 25 h for PmCAP, LpCAP, and the control. Thermal hysteresis (TH) testing of PmCAP and LpCAP proteins revealed TH values of 0.27 °C and 0.72 °C, respectively, relative to 0.05 °C for the BSA control. These results indicate that the two pine dehydrin proteins have antifreeze characteristics and that their antifreeze levels were well in relation to the environmental conditions of pine growth (Larix principis-rupprechtii Mayr mostly grows in cold and high-altitude zones, while Pseudotsuga menziesii grows in temperate and low-altitude zones). LpCAP, especially, could be a better gene resource for the molecular breeding of plant cold resistance. [ABSTRACT FROM AUTHOR]

Main conclusion: Conjugated sugars showed antifreeze activity in the cuticle by ice recrystallization inhibition rather than thermal hysteresis, enhancing freezing capacity at the surface of B. juncea leaves. Antifreeze biomolecules play a crucial role in mitigating the physical damage from frost by controlling extracellular ice crystal growth in plants. Antifreeze proteins (AFPs) are reported from the apoplast of different plants. Interestingly, there is no report about antifreeze properties of the cuticle. Here, we report the potential antifreeze activity in the Brassica juncea (BJ) leaf cuticle. Nano LC-MS/MS analysis of a cuticle protein enriched fraction (CPE) predicted over 30 putative AFPs using CryoProtect server and literature survey. Ice crystal morphology (ICM) and ice recrystallization inhibition (IRI) analysis of ABC supernatant showed heat and pronase-resistant, non-protein antifreeze activities as well as hexagonal ice crystals with TH of 0.17 °C and IRI 46%. The ZipTip processed ABC supernatant (without peptides) had no effect on TH activity, confirming a non-protein antifreeze molecule contributing to activity. To understand the origin and to confirm the source of antifreeze activity, cuticular membranes were isolated by pectinase and cellulase hydrolysis. FTIR analysis of the intact cuticle showed xylose, mannose, cellulose, and glucose. Xylanase and cellulase treatments of the ZipTip processed ABC supernatant led to an increase in sugar content and 50% loss in antifreeze activity. UV spectroscopy and NMR analysis supported the finding of FTIR and enzyme hydrolysis suggesting the contribution of xylose and mannose to antifreeze activity. By TLC analysis, conjugated sugars were found in the cuticle. This work has opened up a new research area where the antifreeze capacity needs to be established with regard to complete characterization and mechanism of action of the antifreeze carbohydrates (conjugated sugars) on the leaf surface. [ABSTRACT FROM AUTHOR]

Thermal error is the main factor that affects the machining accuracy of the machine tools. Error compensation is a convenient and efficient method to reduce the effect of thermal error, and the compensation effect largely depends on the performance of the thermal error model. It is found that the thermal error has an obvious thermal hysteresis effect, and the current thermal error is affected by the previous temperature. Therefore, the thermal hysteresis effect is considered in the thermal error modeling. In this paper, the segmented modeling of the thermal error with variable lag order is studied. Firstly, the thermal characteristics of the spindle system of the gear grinding machine are analyzed and the X-directional thermal hysteresis of the gear grinding machine is theoretically demonstrated. Secondly, according to the temperature-thermal error relationship sketch combined with fuzzy cluster means (FCM) and correlation coefficient, the temperature sensitive points are selected. Thirdly, considering the variable lag order of thermal hysteresis, the lag orders of the heating and cooling processes in every cycle are calculated by particle swarm optimization (PSO). Fourthly, the distributed lag (DL) calculated by the PSO and multiple linear regression (MLR) is used to establish the model in different states, respectively. The S-PSO-DL model is obtained by combining all the segmented models. Compared with the segmented DL model established by mean lag order of inflection point (S-MLO-DL), the segmented back propagation neural network (S-BPNN), the segmented MLR model (S-MLR), and the no-segmented PSO-DL, the maximum residual of the prediction result of S-PSO-DL reduces by 40.8%, 60.0% and 72.8%, 46.3%. Finally, the thermal error of the gear grinding machine spindle is compensated, and the compensation rate of the model reaches 74.3%. [ABSTRACT FROM AUTHOR]

One of the greatest concerns in the subzero storage of cells, tissues, and organs is the ability to control the nucleation or recrystallization of ice. In nature, evidence of these processes, which aid in sustaining internal temperatures below the physiologic freezing point for extended periods of time, is apparent in freeze-avoidant and freeze-tolerant organisms. After decades of studying these proteins, we now have easily accessible compounds and materials capable of recapitulating the mechanisms seen in nature for biopreser-vation applications. The output from this burgeoning area of research can interact synergistically with other novel developments in the field of cryobiology, making it an opportune time for a review on this topic. [ABSTRACT FROM AUTHOR]

The aim of this paper is the development of a qualitative understanding of thermal hysteresis, namely the difference between the melting T m and solidification T s temperatures of nanoparticles as a function of the particle size. In contrast to the melting temperature, the determination of the absolute value of the solidification temperature for nanoparticles is generally more difficult and subjected to significant uncertainties. In this study, we implemented a very generic approach based on classical nucleation theory and define the thermal hysteresis for a nanoparticle relative to its value for a much larger 'reference' particle made of the same material. The obtained thermal hysteresis is found to vanish when decreasing the nanoparticle size. The approach is illustrated using the examples of gold, bismuth, and platinum nanoparticles. [ABSTRACT FROM AUTHOR]

The role of temperature on biological activities and the correspondent exponential relationship with temperature has been known for over a century. However, lacking to date is knowledge relating to (a) the recovery of ectotherms subjected to extreme temperatures in the wild, and (b) the effects repeated extreme temperatures have on the temperatures that induce behavioural thermoregulation (aggregations). We examined these questions by testing the hypothesis that thermal thresholds which initiate aggregations in juvenile Atlantic salmon (AS) (Salmo salar) are not static, but are temporally dynamic across a summer and follow a hysteresis loop. To test our hypothesis, we deployed custom-made underwater camera (UWC) systems in known AS thermal refuges to observe the timing of aggregation events in a natural system and used these data to develop and test models that predict the temperatures that induce thermal aggregations. Consistent with our hypothesis our UWC observations revealed a range of aggregation onset temperatures (AOT) ranging from 24.2°C to 27.1°C, thus confirming our hypothesis that AOTs are dynamic across summer. Our models suggest it take ~ 11 days of non-thermally taxing temperatures for the AOT to rebound in the study river. Conversely, we found that as the frequency of events increased, the AOT declined, from 27.1°C to 24.2°C. Integrating both model components led to more robust model performance. Further, when these models were tested against an independent data set from the same river, the results remained robust. Our findings illustrate the complexity underlying behavioural thermoregulation in AS—a complexity that most likely extends to other salmonids. The frequency of extreme heat events is predicted to increase, and this has the capacity to decrease AOT thresholds in AS, ultimately reducing their resilience to extreme temperature events. [ABSTRACT FROM AUTHOR]

The hysteretic behavior of shape memory alloys (SMA) is technologically important and advantageous in some applications but detrimental in others. In this paper, the effect of stress on the thermal hysteresis of SMA during the martensite transformation is studied. A recently developed discrete particle approach referred to as the continuum based particle dynamics (CPD) is used for this study. The CPD model uses a multibody interactions among the discrete particles which is directly derived from poly-convex free energy pertinent to such material behaviors. In the analysis, temperature of the domain is considered as the control parameter and is varied uniformly through out the domain above and below the transformation temperature. The hysteresis response resulting from this thermal cycle is observed in specific heat-temperature plot (DSC curve) and strain-temperature plot. The effect of prestress on thermal hysteresis along with the corresponding martensite microstructure is modeled. The results show a decrease in hysteresis with increased stress. This effect is attributed to the force required to propagate the ledges along the twin or phase boundary, which is smaller for the stressed material as compared to the stress–free material. [ABSTRACT FROM AUTHOR]

It is well known that CsCl‐type FeRh undergoes from antiferromagnetic (AFM) to ferromagnetic (FM) phase transition near room temperature with large thermal hysteresis. Therefore, it is particularly essential to find new methods to manipulate the magnetic order of FeRh and reduce thermal hysteresis. Herein, the magnetic phase transition of FeRh film by applying a low‐frequency in‐plane alternating current (AC) magnetic field is successfully manipulated. It is found that under the AC magnetic field, the phase transition of the FM–AFM is promoted, and the heating branch shifts at a rate of −8 K T−1, which causes the thermal hysteresis of FeRh reduction of about 2 K. These phenomena may be attributed to the Zeeman energy and the periodic vibration of domain walls. This work provides the possibility for the realization of low‐power spintronic devices. [ABSTRACT FROM AUTHOR]

Spin-crossover solids have been studied for many years for their promising applications as optical switches and reversible high-density memories for information storage. This study reports the effect of random metal dilution on the thermal and structural properties of a spin-crossover single crystal. The analysis is performed on a 2D rectangular lattice using an electro-elastic model. The lattice is made of sites that can switch thermally between the low-spin and high-spin states, accompanied by local volume changes. The model is solved by Monte Carlo simulations, running on the spin states and atomic positions of this compressible 2D lattice. A detailed analysis of metal dilution on the magneto-structural properties allows us to address the following issues: (i) at low dilution rates, the transition is of the first order; (ii) increasing the concentration of dopant results in a decrease in cooperativity and leads to gradual transformations above a threshold concentration, while incomplete spin transitions are obtained for big dopant sizes. The effects of the metal dilution on the spatiotemporal aspects of the spin transition along the thermal transition and on the low-temperature relaxation of the photo-induced metastable high-spin states are also studied. Significant changes in the organization of the spin states are observed for the thermal transition, where the single-domain nucleation caused by the long-range elastic interactions is replaced by a multi-droplet nucleation. As to the issue of the relaxation curves: their shape transforms from a sigmoidal shape, characteristic of strong cooperative systems, into stretched exponentials for high dilution rates, which is the signature of a disordered system. [ABSTRACT FROM AUTHOR]

The entropy changes in successive martensitic phase transformations in Ni-Mn-Ga Heusler alloys can be used to realize enhanced magnetocaloric properties. A detailed study of phase transformations of one such alloy, Ni2.15Mn0.85Ga ($\Delta Q =4900$ J/kg at 343 K, under 140 kOe), is reported here. Upon cooling, the paramagnetic cubic (L21) austenitic phase transforms into a ferromagnetic 7M modulated monoclinic martensitic phase. This phase is stable in a narrow temperature range, and upon further cooling, it transforms into a non-modulated ferromagnetic tetragonal (L10) phase. The separation between the equilibrium temperatures of the austenitic and tetragonal martensitic phases is only ~50 K. The alloy undergoes reversible temperature-induced martensitic and inter-martensitic phase transformations with thermal hysteresis of about 25 K. The conclusions from the detailed study of the phase transformations lead to new possibilities to enhance the magnetocaloric effect (MCE) using the entropy associated with multi-structural transformations. [ABSTRACT FROM AUTHOR]

A temperature-dependent Raman experiment between 80 and 600 K was performed in a nanoparticulated coating of single-phase hematite grown on a silica substrate. In that range, a thermal Raman shift hysteresis was identified in the vibrational modes that accompanies the Morin transition, observing large effects in the two-magnon Raman frequency position and in its relative intensity. Interestingly, no decrease in coercivity occurs when the hematite crosses the Morin transition below 230 K. The spin-flop processes produced in the coating leads to a strong decompensation of the surface spins, generating a ferromagnetic component over the whole temperature range studied. Such unusual effects might be promoted by a certain degree of structural disorder and the stresses produced by the nanoparticulation growth approach of the hematite coating. As a result, a high stability of the two-magnon excitation is obtained over a wide temperature range and considerable advances are made for the development of spintronic devices based on semiconductor antiferromagnetic materials. [ABSTRACT FROM AUTHOR]

This article describes thermal input/concentration output systems processed by chemical reactions. Various sophisticated thermal inputs can be converted into concentration outputs through the double-helix formation of helicene oligomers exhibiting thermal hysteresis. The inputs include high or low temperature, cooling or heating state, slow or fast cooling state, heating state, and cooling history. The chemical basis for the properties of the chemical reactions includes the reversibility out of chemical equilibrium, sigmoidal relationship and kinetics, bistability involving metastable states, positive feedback by self-catalytic chemical reactions, competitive chemical reactions, and fine tunability for parallel processing. The interfacing of concentration outputs in other systems is considered, and biological cells are considered to have been utilizing such input/output systems processed by chemical reactions. [ABSTRACT FROM AUTHOR]

Bistable spin‐crossover (SCO) complexes that undergo abrupt and hysteretic (ΔT1/2) spin‐state switching are desirable for molecule‐based switching and memory applications. In this study, we report on structural facets governing hysteretic SCO in a set of iron(II)‐2,6‐bis(1H‐pyrazol‐1‐yl)pyridine) (bpp) complexes – [Fe(bpp−COOEt)2](X)2⋅CH3NO2 (X=ClO4, 1; X=BF4, 2). Stable spin‐state switching – T1/2=288 K; ΔT1/2=62 K – is observed for 1, whereas 2 undergoes above‐room‐temperature lattice‐solvent content‐dependent SCO – T1/2=331 K; ΔT1/2=43 K. Variable‐temperature single‐crystal X‐ray diffraction studies of the complexes revealed pronounced molecular reorganizations – from the Jahn‐Teller‐distorted HS state to the less distorted LS state – and conformation switching of the ethyl group of the COOEt substituent upon SCO. Consequently, we propose that the large structural reorganizations rendered SCO hysteretic in 1 and 2. Such insights shedding light on the molecular origin of thermal hysteresis might enable the design of technologically relevant molecule‐based switching and memory elements. [ABSTRACT FROM AUTHOR]

By constructing the thermal hysteresis of the enthalpy and density of the noble metals of gold (Au) and copper (Cu), non-equilibrium processes are investigated during the melting - crystallization phase transformations, i.e. during the solid-liquid transition. Thermal hysteresis is obtained from the atomistic modeling. The limiting temperatures of superheating of the solid phase during melting and undercooling of the liquid phase during crystallization of gold and copper are obtained. The possibility of the formation of highly superheatedundercooled metastable states of solid and liquid phases with rapid heating-cooling of the studied metals has been confirmed. The results obtained are compared with the results of alternative calculations. [ABSTRACT FROM AUTHOR]

The frequency–temperature (${f}$ – ${T}$) characteristic of quartz crystal resonators is an important topic closely related to the frequency-deviation compensation in the design of cost-effective oscillators. Traditional studies depict the ${f}$ – ${T}$ characteristic as a polynomial function (usually a cubic function). However, this omits the thermal hysteresis phenomenon and cannot provide a very accurate frequency compensation. To handle this issue, this article is to propose two modified ${f}$ – ${T}$ characteristic modeling methods with considering the thermal hysteresis. First, to reflect the thermal hysteresis property of quartz crystal resonators, a two-directional ${f}$ – ${T}$ model is designed by introducing two individual submodels for describing the increasing and decreasing temperature stages, respectively. Furthermore, to integrate the submodels and provide the more accurate frequency-deviation estimation, a holistic ${f}$ – ${T}$ characteristic model based on double-hidden layer extreme learning machine (DHL-ELM) is presented. Different from the basic ELM model, two hidden layers, including one deterministic nonlinear mapping and one random nonlinear activation layer, are constructed for a better description of ${f}$ – ${T}$ characteristic. To validate our studies, an experiment system is applied to obtain the testing data of the real crystal resonators, and the applications demonstrate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

The present study presents the magnetocaloric effect (MCE) properties of Ni-rich Ni50−xCoxMn38Sn12B3 (x = 0, 1, 3, 5) ribbons during both heating and cooling processes. The Co substitution caused an increase of magnetization difference ΔM and hence an improvement of the MCE. An inverse giant magnetocaloric effect (IMCE) and a high effective refrigerant capacity RCeff were observed in the x = 3 ribbons. A high amount of Co (x = 5) content led to an inverse magnetic entropy ΔSM peak with a wide temperature range. Magnetostructural coupling over a wide temperature range is of great importance for technological purposes. On the other hand, the MCE properties were thermal hysteresis dependent, which has to be considered in the technological applications. [ABSTRACT FROM AUTHOR]

A general ice block is made of infinite number of single ice crystals, whose embryos are generated at the moment of freezing. Antifreeze protein (AFP) or antifreeze glycoprotein (AFGP) accumulates on the specific surfaces of such embryonic ice crystals, which suppresses their ice growth and stabilizes a supercooled solution. This mechanism has been thought to provide cold-tolerance for an organism, and realize new freezing preservation techniques of various water-containing materials, such as processed foods, gels, noodles, doughs, seeds, fruits, vegetables, ice creams, polymers, medicines, cosmetics, cells, tissues, and organs. If the proteins can make the ice crystal size ultimately small, they will significantly improve the effectiveness of the preservations. In addition, many AFPs bind to the lipid bilayer to prolong lifetime of cells under hypothermic condition (+4°C), for which applicability to unfrozen, short-term cell preservation can be expected. The author has therefore been tried to clarify the functional mechanism of AFPs and AFGP, and further developed their mass-preparation method to find their usefulness in both industrial and medical fields. This article provides advanced knowledge obtained through the works mainly performed by the author. [ABSTRACT FROM AUTHOR]

The behavior of thermal hysteresis of 2-D hexagonal spin-crossover nanosystem was studied on the basis of microscopic approach, using an Ising-like model. The results were obtained using Monte Carlo method based on the Metropolis algorithm. In the framework of the considered model, a relation between the system size and interaction strength of the neighbor spin-crossover molecules was established. By applying external pressure, a narrowing of the system's hysteresis and a shift of the transition curves toward higher temperature were observed. The application of pressure also leads to a switching between the HS and LS states of the system, which makes such system promising and desirable in sensor applications (as pressure sensors). The influence of the defects on the system transition curves was investigated. Presence of which leads to the narrowing of the hysteresis width. The obtained results of numerical simulations are in accordance with available theoretical and experimental ones of other authors. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Functional Materials / Gongneng Cailiao is the property of Chongqing Functional Materials Periodical Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The activity of solid electrolytes from the family of Na(Cs)–Mx–Zr phosphates (NZP and CZP) with dopant ions M+2 = Co+2 and Ni+2 synthesized by the sol–gel method is studied in the gas-phase transformations of isopropanol and isobutanol. It is found that the amount of M+2 and its nature, as well as the direction of a change in the catalyst temperature (heating or cooling in the range of 473−693 K), affects the activity of M-NZP and M-CZP. In the transformation of isopropanol, hysteresis of the acetone yield, counter-clockwise (type I) for Co-NZP and clockwise (type II) for Ni-NZP, is observed in the heating–cooling cycles. An increase in the activity of Co-NZP in the cooling mode (type I) is related to a rise in the apparent activation energy of alcohol dehydrogenation under conditions of the formation of new catalytically active sites in the form of a Co+2−Zr+4 → Co+3−Zr+3 ion pair with the oxidized form of M and the reduced form of Zr. Type I hysteresis of the total alcohol conversion is observed in the transformations of isobutanol to olefin and aldehyde over Co(Ni)-CZP. The hysteresis is associated with a decrease in the activation energy of alcohol dehydrogenation. The main reaction over the Co(Ni)-CZP catalysts is the dehydration of alcohol with an increase in the activation energy of the reaction upon cooling, for example, by 53 kJ/mol for Ni0.25-CZP. [ABSTRACT FROM AUTHOR]

Antifreeze proteins (AFPs) modify the ice shape and inhibit further growth leading to thermal hysteresis (TH). Numerous studies have been performed with the addtition of AFPs to preserve frozen products but the influence of sucrose on the effects of AFPs has not been investigated as of yet. Therefore, the TH activities of type I antifreeze protein (AFP I) and antifreeze glycoprotein (AFGP) were measured as a function of concentration, type of AFPs, and also sucrose concentration. The results showed that the TH values rose with increase in concentration of AFPs and sucrose concentration. The crystals experienced shape modification and grew in the c‐axis direction in the presence of both AFPs. The bursting rate of crystals changed depending on both the concentrations of AFPs and sucrose. [ABSTRACT FROM AUTHOR]

Hysteresis phenomena, including both electrical and thermal types, are essential to ferroelectric materials. The former, known as polarization‐electric field hysteresis, has been intensively studied in a wide range of ferroelectric materials. However, relevant experimental evidence on thermal hysteresis remains limited, especially in ferroelectric polymers, even though thermal hysteresis is crucial to the caloric effect, which is usually the largest near the phase transition. Here, the thermal hysteresis behavior in ferroelectric polymers is studied in terms of temperature‐dependent polarization upon heating and cooling. In contrast to common belief, a negative thermal hysteresis is observed in relaxor ferroelectric polymers, which is probably due to local stabilization of ferroelectric distortion induced by electric field. Using the polymer blend as a platform, it is further shown that the negative thermal hysteresis arises at the disappearance of long‐range ferroelectric distortion and the thermal hysteresis behavior may be effectively controlled through the blend approach. This study not only provides deeper insights into electrocaloric effect in ferroelectric polymers but also offers an approach to study the critical phenomenon in a ferroelectric system. [ABSTRACT FROM AUTHOR]

Measurements of ice recrystallization inhibition (IRI) and thermal hysteresis (TH) activities of kappa (κ)‐ and iota (ι)‐carrageenans were carried out to examine whether they can be novel cryoprotectants or not. IRI measurements indicate that both carrageenans reduce recrystallization in sucrose solution, but that the IRI activity of κ‐carregeenan is higher than that of ι‐carrageenan. TH measurements indicate that κ‐ and ι‐carrageenans do not exhibit TH activity. TH activity measurements of antifreeze glycoprotein (AFGP) in the presence of κ‐carregeenan demonstrate that this carregeenan neither influences the TH activity of AFGP nor the shape of the ice crystals. The round ice crystal shape transformed into an angular and elongated shape in the presence of both carregeenans. [ABSTRACT FROM AUTHOR]

Deschampsia antarctica has managed to colonize the maritime Antarctic. One of the main factors associated with its tolerance to low temperatures is the presence of apoplastic proteins with antifreeze activity. This work focuses on the effect of cold acclimation of D. antarctica on the accumulation of apoplastic proteins with antifreeze activity. Antifreeze proteins present in apoplastic extracts were purified by ice affinity purification, and their identity was determined by protein sequencing. D. antarctica plants were subjected to 22 days of cold acclimation at 4 °C. The highest content of apoplastic proteins with antifreeze activity was obtained at between 12 and 16 days of acclimation. Protein sequencing allowed their identification with >95% probability. Percentage coverage was 74% with D. antarctica ice recrystallization inhibition protein 1 (DaIRIP1) and 55% with DaIRIP3. Cold acclimation of D. antarctica improved the yield of apoplastic proteins, and resulted in an increase in the antifreeze activity of apoplastic extracts. An in silico analysis suggested that the fluctuations presented by the three-dimensional structures of DaIRIPs help to explain the presence of certain DaIRIPs in apoplastic extracts under the cold acclimation conditions evaluated. [ABSTRACT FROM AUTHOR]

Manipulating the collective molecular movements to implement macroscopic mechanical response of bulk material is attractive and challenging. Here, an organic‐inorganic hybrid single crystal is synthesized, which exhibits a giant macroscopic shape transformation with a remarkable thermal hysteretic feature. The colossal anisotropic shape change, which manifests as an abrupt elongation of ca. 9 % along the crystallographic c‐axis and a concomitant contraction of ca. 9 % in a perpendicular direction, is induced by a significant reorientation of imidazolium, accompanied with a substantial configurational variation in CuBr42− complex anions. The synergistic motions of both the molecular cations and anions engender a remarkable large thermal hysteresis (>30 K) in the shape transformation of the single crystal, implying that this material may play a role in alternating memory media. Furthermore, due to the stable crystal lattice, a single crystal that demonstrates naked‐eye detectable large shape transformation was used as a thermal actuator to spontaneously control an electric circuit by temperature variation. [ABSTRACT FROM AUTHOR]

The freezing of water is usually fatal to most organisms because it causes extensive damage to cell membranes due to the formation of ice crystals. However, several structurally different classes of antifreeze proteins (AFPs) found in fish, insects, plants, and microorganisms, including bacteria, yeast, and fungi, have been found to be capable of modifying the growth of ice crystals by thermal hysteresis and ice recrystallization inhibition. This unique property could potentially be applied to medicine and the industry as it is useful when low-temperature storage is required and ice crystallization must be avoided. However, the application of AFPs today is not economically viable due to the complexity of the large proteins, the laborious procedures required, and the low yields obtained. A wide range of peptides mimicking their parent proteins were recently successfully designed and chemically synthesized. The developed approaches present new opportunities to understand the structure-function relationship of small-structured peptides with antifreeze properties. This mini-review highlights the diversity, classification, and properties of AFPs. The emerging applications of short mimetic peptides of AFPs and their potential application are also described. [ABSTRACT FROM AUTHOR]

This study reports the intercalation of pyridine molecules between neighboring layers of two‐dimensional (2D) ferrous nitroprusside. In the material under study, the stacking of neighboring layers results in the formation of a long range ordered solid, where the 3D structure is supported by dipole‐dipole attractive interactions between neighboring pyridine molecules in the interlayer region. No chemical interactions were observed between layers, which preserve their identity as a 2D material. In this hybrid inorganic–organic solid, a thermal induced spin transitions from high to low spin on cooling and then from low to high spin on heating were observed. Such thermal induced spin crossover transition takes place with a pronounced hysteresis of 18 K, according to the magnetic and DSC measurements. That spin crossover transition is characterized by an extremely small structural change, involved a unit cell volume reduction from the high to low spin states of only 0.7 % and a related Fe–NPyridine distance shortening of 0.10 Å. The two spin states and the transition between them were additionally characterized from magnetic and DSC data and, Raman and Mössbauer spectra. [ABSTRACT FROM AUTHOR]

The Mn1.15Fe0.80P0.50Si0.50Cx compounds with x = 0, 0.01, 0.03, and 0.05 were prepared by twice solid-phase sintering and we investigated the changes of the structure and magnetocaloric properties by C doping. All samples are found to show Fe2P-type structure with minor impurity phase and some carbon atoms enter into Fe2P-type main phase and occupy the interstitial site. Carbon addition leads to an increase of the Curie temperature from 289 to 321 K and the thermal hysteresis has a reduction about 31.5%. All samples show distinct first-order magnetic transition. The peak value of magnetic entropy change and adiabatic temperature change is increased by 26% and 11% with addition of carbon under a low field of 0–2 T, respectively. The large magnetocaloric effect might be resulted from the latent heat of phase transition induced by temperature derived from calorimetric measurements. The results indicate that (Mn,Fe)2PSiC compound with large magnetocaloric effect is a good candidate for room temperature magnetic refrigeration. [ABSTRACT FROM AUTHOR]

Ice-binding proteins (IBPs) inhibit the growth and recrystallization of intracellular ice, enabling polar organisms to survive at subzero temperatures. IBPs are promising materials in biomedical applications such as cryopreservation and the hypothermic storage of cells, tissues, and organs. In this study, recombinant IBP from the antarctic bacterium Flavobacterium frigoris PS1 (FfIBP) was produced by Escherichia coli used as bioreactor, to examine the feasibility of scale-up. Oxygen transfer was the most important factor influencing cell growth and FfIBP production during pilot-scale fermentation. The final yield of recombinant FfIBP produced by E. coli harboring the pET28a-FfIBP vector system was 1.6 g/L, 3.8-fold higher than that from the previously published report using pCold I-FfIBP vector system, and its thermal hysteresis activity was 2.5°C at 9.7 µM. This study demonstrates the successful pilot-scale production of FfIBP. [ABSTRACT FROM AUTHOR]

Ice-binding proteins (IBPs) are unique molecules that bind to and are active on the interface between two phases of water: ice and liquid water. This property allows them to affect ice growth in multiple ways: shaping ice crystals, suppressing the freezing point, inhibiting recrystallization and promoting nucleation. Advances in the protein's production technologies make these proteins promising agents for medical applications among others. Here, we focus on a special class of IBPs that suppress freezing by causing thermal hysteresis (TH): antifreeze proteins (AFPs). The kinetic pinning model describes the dynamics of a growing ice face with proteins binding to it, which eventually slow it down to a halt. We use the kinetic pinning model, with some adjustments made, to study the TH dependence on the solution's concentration of AFPs by fitting the model to published experimental data. We find this model describes the activity of (moderate) type III AFPs well, but is inadequate for the (hyperactive) Tenebrio molitor AFPs. We also find the engulfment resistance to be a key parameter, which depends on the protein's size. Finally, we explain intuitively how TH depends on the seeding time of the ice crystal in the protein solution. Using this insight, we explain the discrepancy in TH measurements between different assays. This article is part of the theme issue 'The physics and chemistry of ice: scaffolding across scales, from the viability of life to the formation of planets'. [ABSTRACT FROM AUTHOR]

In this research, four high temperature shape memory alloys, Ti50Ni25-xPd25Cux (x = 0, 5, 10 and 15) were developed and designated 0Cu, 5 Cu, 10 Cu, and 15Cu, respectively. The effect of 5%, 10%, and 15% (all in atomic percent) Cu addition was investigated through their microstructure analysis, transformation temperatures and thermal stability. After the alloying of Cu content in their desired percentage, the alloys were named as 0Cu, 5Cu, 10Cu and 15Cu alloys. The martensite onset temperature Ms of ternary 0Cu alloy increased by 12.5 ℃, 27.5 ℃ and 60.5 ℃, respectively, by replacement of Ni with 5%, 10% and 15% Cu. Similarly, the austenite finish temperature Af increased by 11 ℃, 25 ℃, and 52 ℃, respectively. At the same time, thermal hysteresis of the 5Cu, 10Cu, and 15Cu alloys decreased by 1.5 ℃, 2.5 ℃, and 8.5 ℃, respectively, as compared to 0Cu alloy. The thermal stability of ternary 0Cu alloy was improved by replacing Ni with Cu. During thermal cycling, the net drop in Ms and Af of 0Cu alloy was 7.5 ℃ and 14 ℃, respectively. By replacing Ni with 5%, 10%, and 15% Cu, the net drop in Ms decreased to 5 ℃, 3.7 ℃, and 3 ℃, respectively, whereas the net drop in Af decreased to 10 ℃, 8.7 ℃, and 5 ℃. The overall results suggested that by the addition of 5%, 10%, and 15% Cu in place of Ni in TiNiPd alloys, the transformation temperatures and thermal stability improved. At the same time, thermal hysteresis decreased to a reasonable level which has a positive effect on the actuation behavior. [ABSTRACT FROM AUTHOR]

A semiconducting organic‐inorganic hybrid compound [(C6H15ClNO)2CdBr4] (1), which displays excellent switchable dielectric, has been successfully synthesized. Systematic characterizations including variable‐temperature structural analyses, DSC, TG, variable‐temperature dielectric measurements, solid‐state UV/Vis diffuse reflectance and photoluminescence were performed. DSC curve shows a couple of reversible heat anomaly peaks at 363/322 K on the heating/cooling process with a very large thermal hysteresis of ∼41 K, indicating the first‐order type of phase transition. Obvious dielectric switching occurs at about 364 K and 314 K also with a large thermal hysteresis of ∼50 K in the heating and cooling process, respectively. The large phase transition thermal hysteresis makes 1 a potential latent heat based thermal energy storage materials which can maintain the system over a wide temperature range. Variable‐temperature structural analyses show that the rotating or orientating movement of anion clusters is the mainly attribution for the phase transition of 1. A semiconducting organic‐inorganic hybrid metal halide [(C6H15ClNO)2CdBr4] exhibits switchable dielectric and a large phase transition thermal hysteresis of ∼50 K due to temperature‐triggered rotating or orientating movement of anion clusters. [ABSTRACT FROM AUTHOR]

Ice‐binding proteins (IBPs) control the growth and shape of ice crystals to cope with subzero temperatures in psychrophilic and freeze‐tolerant organisms. Recently, numerous proteins containing the domain of unknown function (DUF) 3494 were found to bind ice crystals and, hence, are classified as IBPs. DUF3494 IBPs constitute today the most widespread of the known IBP families. They can be found in different organisms including bacteria, yeasts and microalgae, supporting the hypothesis of horizontal transfer of its gene. Although the 3D structure is always a discontinuous β‐solenoid with a triangular cross‐section and an adjacent alpha‐helix, DUF3494 IBPs present very diverse activities in terms of the magnitude of their thermal hysteresis and inhibition of ice recrystallization. The proteins are secreted into the environments around the host cells or are anchored on their cell membranes. This review covers several aspects of this new class of IBPs, which promise to leave their mark on several research fields including structural biology, protein biochemistry and cryobiology. Many psychrophilic microorganisms have proteins that contain the domain of unknown function (DUF) 3494. All analysed examples of this domain share the same discontinuous β‐solenoid fold and the ability to bind ice crystals, marking DUF3494 as a signature for a new class of ice‐binding proteins reviewed here. Despite these similarities, the members of this class are diverse in their biological sources, abilities to control ice growth and potential biological functions. [ABSTRACT FROM AUTHOR]

Abstract: Magnetocaloric materials relying on first‐order phase transitions give the highest entropy changes compared to second‐order transitions. However, they have the drawback of a transformation hysteresis, which reduces the efficiency of a cooling cycle. Here an approach to reduce the thermal hysteresis losses by performing incomplete transformation cycles, so called minor loops, is presented. A freestanding, epitaxially grown Ni–Mn–Ga–Co film is used as a model system to analyze the direct martensitic and reverse transformation paths in detail. The additional residual phase fraction only facilitates the forward martensitic transformation, but not the reverse transformation. This pronounced asymmetry between cooling and heating demonstrates that the forward transformation to martensite is controlled by nucleation and the associated excess energy contributes to hysteresis losses. For the reverse transformation, however, nuclei of austenite are always present and accordingly this transformation is controlled by growth of the austenitic phase. The experiments reveal that only the use of heating minor loops is useful to improve the efficiency of magnetocaloric epitaxial films and by this, the ratio of usable magnetization difference divided by hysteresis loss can be increased by 64 %. [ABSTRACT FROM AUTHOR]

Ice‐binding proteins (IBPs) contribute to the survival of many living beings at subzero temperature by controlling the formation and growth of ice crystals. This work investigates the structural basis of the ice‐binding properties of EfcIBP, obtained from Antarctic bacteria. EfcIBP is endowed with a unique combination of thermal hysteresis and ice recrystallization inhibition activity. The three‐dimensional structure, solved at 0.84 Å resolution, shows that EfcIBP belongs to the IBP‐1 fold family, and is organized in a right‐handed β‐solenoid with a triangular cross‐section that forms three protein surfaces, named A, B, and C faces. However, EfcIBP diverges from other IBP‐1 fold proteins in relevant structural features including the lack of a ‘capping’ region on top of the β‐solenoid, and in the sequence and organization of the regions exposed to ice that, in EfcIBP, reveal the presence of threonine‐rich ice‐binding motifs. Docking experiments and site‐directed mutagenesis pinpoint that EfcIBP binds ice crystals not only via its B face, as common to other IBPs, but also via ice‐binding sites on the C face. Database: Coordinates and structure factors have been deposited in the Protein Data Bank under accession number 6EIO. [ABSTRACT FROM AUTHOR]

We have studied systematically the pressurecomposition-temperature ( P- C- T) hydrogen absorption/release relation curves of LaFeSi and LaFeSi compounds. The effects of pressure, composition, temperature, and time on the process of hydrogenating have been investigated. The results indicate that the volume of unit cell can be expanded after hydrogenating without changing the cubic NaZn-type crystal structure. The LaFeSiH and LaFeSiH compounds can be prepared separately under different hydrogen pressures at 423 K. The Curie temperature ( T ) can be increased, the thermal hysteresis can be decreased, and the magnetic entropy change can be maintained at a high standard after hydrogenating in LaFeSi and LaFeSi compounds. With prolonged exposure time in air, the magnetic properties and magneto-caloric effect (MCE) can be maintained at a relatively ideal level, implying that the La(Fe, Si) hydrides have a good time stability. [ABSTRACT FROM AUTHOR]

A study of the Pd-containing catalyst based on manganese hexaaluminate by X-ray diffraction analysis, transmission electron microscopy, thermo-programmed reduction with hydrogen, and thermo-programmed oxidation showed the hysteresis manifested itself in a difference between the temperature dependences of its catalytic activity in the oxidation of methane under the conditions of sample heating or cooling is related to the decomposition of PdO to metallic palladium at temperatures higher than 700–800°C and the subsequent formation of PdO nanoparticles, which are localized on the surface of metallic Pd (30–50 nm) in the form of polycrystalline films with a thickness of 2–5 nm, at temperatures lower than 600–700°C. A near-surface oxide film is formed under the conditions of cooling in oxygen-containing atmospheres, including in the presence of methane. The value of the hysteresis depends on the heat treatment temperature of the catalyst, and it reaches a maximum on the catalysts calcined at 900 and 1000°C. [ABSTRACT FROM AUTHOR]

Antifreeze proteins (AFPs) are unique proteins that have an affinity toward ice. Due to their potential applications in the food and medical industries, many attempts have been made to produce AFPs in large quantities. In this study, recombinant Afp1 from Glaciozyma antarctica, a psychrophilic yeast, was overexpressed in a methylotrophic yeast, Pichia pastoris, followed by 5-L fermenter expression. The highest yield of Afp obtained from the fermentation was 39.5 mg/L when the cells were cultivated at 16 °C and at pH 5.0. Afp1 was produced as a glycoprotein (~55 kDa) based on gel staining using a glycoprotein kit. Antifreeze activities of the recombinant Afp1 were exhibited through thermal hysteresis (TH) and recrystallization inhibition (RI) where the highest TH value recorded was at ~0.5 °C at 10 mg/mL. This value is higher when compared to the recombinant Afp1 produced in Escherichia coli (0.08 °C) as well as the native antifreeze protein from G. antarctica (0.1 °C). Both TH and RI activities increased when higher protein concentrations were used. Effects of temperature on stability showed that Afp1 had lost its activity after being incubated at a temperature higher than 20 °C. The cryoprotective effects of Afp1 on cellulases showed that the treated cellulase retained up to ~20% of its activity following several cycles of freeze-thawing. This indicates that Afp1 might act as a cryoprotective agent and has the potential for use in biotechnology applications. [ABSTRACT FROM AUTHOR]

Relaxation phenomena in metal interconnects are a potential source of drift in piezoresistive pressure sensors. Since the properties of a metal film are influenced by its fabrication process, it is of interest to study such phenomena in an environment that resembles a production device. For this purpose, a piezoresistive pressure sensor has been modified for characterization of thin film metallization. Extra metal has been placed on the passivation layer over the piezoresistors such that the strain in the metal can be controlled isothermally by applying a test pressure as well as by temperature. We show that the sensor output signal contains information on the stress development in the metal film. By limiting the design modification to one metal mask only, we have achieved a cost effective approach for characterization of metal properties with test structures that can be processed together with functional devices. [2017-0074] [ABSTRACT FROM PUBLISHER]

The processes of melting and solidification of the eutectic Sn-43 mol % Bi alloy are studied by cyclic thermal analysis. It is found that this alloy melts at a temperature T = 412 K (which corresponds to the reference melting temperature of the eutectic) upon heating and solidifies isothermally at a temperature T = 394 K upon cooling; that is, the temperature difference is Δ T = 18 K. A comparison of temperatures T and T reveals a temperature hysteresis (TH). The activities and the activity coefficients of tin and bismuth in the eutectic are calculated at temperatures T and T . The enthalpies of melting at T and solidification at TS are measured. The ways of changing the Gibbs energy during TH are determined. [ABSTRACT FROM AUTHOR]

Positive displacement motor (PDM), which is prone to high temperature fatigue failure, can be weakened in its application in deep and superdeep well. In order to study the forced state, deformation regularity and thermal hysteresis of PDM motor, the paper established the three-dimensional thermal-mechanical coupled Finite element model (FEM). Based on the theoretical research, experimental study and numerical simulation, the study found that the displacement of stator lining shows a sinusoidal variation under internal pressure, when adapting the general form of sine function to fitting inner contour line deformation function. Then the paper analyzed the hysteresis heat generating mechanism of the motor, learning that hysteresis thermogenous of stator lining occurs due to the viscoelastic of rubber material and cyclic loading of stator lining. A heartburn happens gradually in the center of the thickest part of the stator lining as temperature increases, which means work efficiency and service life of PDM will be decreased when used in deep or superdeep well. In this paper, we established a theory equation for the choice of interference fit and motor linetype optimization design, showing hysteresis heat generating analyzing model and method are reasonable enough to significantly improve PDM's structure and help better use PDM in deep and surdeep well. [ABSTRACT FROM AUTHOR]