Non-isothermal crystallization of LiNaGe4O9 glass

The glass of lithium-sodium tetragermanate LiNaGe4O9 is crystallized on heating under the control of differential scanning calorimetry and thermal gravimetric analysis. The measurements were prepared in the temperature range 300-870 K and showed the relatively weak endothermic DSC anomaly and 40-50 K above the single exothermic peak. The endothermic anomaly observed at Tg testified to softening the glass structure whereas the exothermic peak at TC manifested crystallization of the amorphous phase. Studying of TGA demonstrated smooth nearly linear dependences without any visible anomalies. Varying the heating rate from 1.2 up to 40 K/min resulted in noticeable increase of the characteristic temperatures Tg and TC. Lower limit of the glass transition temperature Tg0 was estimated with the help of the existing model. The mechanism of the LiNaGe4O9 glass crystallization is discussed.

Unifying fluctuation-dissipation temperatures of slow-evolving nonequilibrium systems from the perspective of inherent structures

For nonequilibrium systems, how to define temperature is one of the key and difficult issues to solve. Although effective temperatures have been proposed and studied to this end, it still remains elusive what they actually are. Here, we focus on the fluctuation-dissipation temperatures and report that such effective temperatures of slow-evolving systems represent characteristic temperatures of their equilibrium counterparts. By calculating the fluctuation-dissipation relation of inherent structures, we obtain a temperature-like quantity TIS. For monocomponent crystal-formers, TIS agrees well with the crystallization temperature Tc, while it matches with the onset temperature Ton for glass-formers. It also agrees with effective temperatures of typical nonequilibrium systems, such as aging glasses, quasi-static shear flows, and quasi-static self-propelled flows. From the unique perspective of inherent structures, our study reveals the nature of effective temperatures and the underlying connections between nonequilibrium and equilibrium systems and confirms the equivalence between Ton and Tc.

Setting the functional properties of TiNi alloys during ion-plasma coating deposition process

The aim of the present work is to study the influence of the technological parameters of the ion-plasma treatment (IPT) on the functional properties of a TiNi shape memory alloy and its biocompatibility. The object of the study was the Ti–50.8 at. % Ni alloy, widely applied in medical devices. IPT was carried out by vacuum-arc evaporation of a titanium cathode at different values of the bias potential (0, –100, and –500 V), followed by TiN deposition. The functional properties of the TiNi alloy after IPT were investigated using differential scanning calorimetry. The biocompatible properties were evaluated using atomic emission spectrometry to measure a nickel concentration after one year holding TiN-coated TiNi samples in the 0.9 % NaCl solution. It has been determined that by setting the temperature regime of heating of Ti–50.8 at. % Ni alloy samples due to the technological parameters of the IPT process, it is possible to change the interval of realization of thermoelastic martensitic transformations, and, consequently, the temperature response of devices made of this alloy, i. e. to set the necessary functional properties. The comparative analysis of the characteristic temperatures after heat and ion-plasma treatments allow us to conclude that the proposed method for calculation of the TiNi substrate temperature is correct at IPT. The calculated temperature of the TiNi samples was ~275 °C at the zero potential, which is sufficient to shift the characteristic temperatures of the alloy. The substrate temperature during deposition was ~400 °C at a – 100 V bias and above 600 °C at a – 500 V bias, respectively. The Ni concentration in the model solution did not exceed 0.14 mg/l after one year holding, which indicates the high biocompatibility of the TiN-coated TiNi samples.

In situ TEM-исследование фазовых превращений в нестехиометрическом сплаве Гейслера Ni-=SUB=-46-=/SUB=-Mn-=SUB=-41-=/SUB=-In-=SUB=-13-=/SUB=-

This paper presents a study of the metamagnetostructural transition of the martensitic type in the Ni46Mn41In13 alloy with magnetic shape memory and inverse magnetocaloric effect. The characteristic temperatures of the direct transition starting Ms = 253 K and its finishing Mf = 164 K, as well as the reverse temperatures As = 203 K and Af = 236 K, respectively, were determined by differential scanning calorimetry. The characteristic peculiarities of the transition: a decrease of the Ms and the presence of a residual austenite phase, as well as pre-martensitic states, were studied using transmission electron microscopy. The estimated the thickness of alloy was 50 nm, when martensitic transition suppressed.

Developing a comprehensive GIS tool to evaluate representative parameters regarding life comfort

In this paper, we present a tool dedicated to assessing life quality according to the notion of comfort which can link three aspects of noise, light, and air pollution with two aspects of thermal and odour discomfort because the beforementioned aspects are using different calculation methods of the parameters which are distinct and some of them are defined in the national or EU legislation. The authors developed a compressive database to evaluate representative quantities of energy loses. There were considered some performance indicators as: energy class, total specific energy consumption, CO2 equivalent emission index, the overall heat transfer coefficient of the building and characteristic temperatures, the corrected number of degrees days, and the duration of the heating season - at locality level.

The thermophysical properties of primary phase in lithium germanium phosphate glass

The selected lithium germanium-phosphate glass was prepared by a conventional melt-quenching technique. The XRD method was employed to confirm the glass was obtained and to reveal crystalline phases during heat treatment. The dilatometry (DIL), differential thermal analysis (DTA), and differential scanning calorimetry (DSC) were used to determine the characteristic temperatures and enthalpies of crystallization and melting of the crystalline phase. The DTA and DIL were used to obtain the viscosity curves by applying the Vogel-Fulcher-Tammann (VFT) equation