Search

Due to high densities of energy, power, and remarkable operational efficiency of Li-on battery when in contrast to Lead-acid batteries and nickel-cadmium batteries are examples of other types of batteries. Vehicles, electronics, aircraft, and other industries are all interested in lithium-ion batteries right now. However, some critical variables, such as performance degradation under extreme driving circumstances due to temperature difference in the lithium-ion cell, limit its usefulness. As a result, it's important to decide the optimal course of action based on the consequences of heat generation on various lithium-ion cell components. This paper looked at how heat is generated and how it affects each component of a li-ion battery. An analysis of different heat-controlling systems employing various design structures in numerous techniques of cooling such as liquid convection, phase transition material, air Convection and a combination of these techniques are used. Finally, utilizing a variety of design frameworks, a summary is created [ABSTRACT FROM AUTHOR]

The present paper analyzes failure observed in polymer rods collided with a steel anvil under the Taylor cylinder impact experiments. The experimental and numerical analysis demonstrates that association of the failure patterns with the loading mode depends on the rod material. Two materials are considered in the paper, specifically, polymethylmethacrylate (PMMA) and polycarbonate (PC). Damage in PMMA rods at the Taylor tests is shown to be dominated by the shear load resulting in plastic deformation. In contrast, the major mechanism of damage in PC rods is governed by omni-directional (pressure) mode of load. Analysis of the damage in sections of the rods associated with the glass transition is also addressed in the present theoretical study. Failure in these polymers follows the traditional fracture wave mechanism for brittle glass-type materials due to load in the corresponding mode. Numerical analysis employs a two-phase model with improved inter-phase thermal balance accounting for the inter-phase mass, momentum, and heat exchanges during the glass phase transition, while damage being accumulated in time. The simulation results demonstrate a good correlation with the experimental results. [ABSTRACT FROM AUTHOR]

The first, and at the same time one of the most important tasks in building a predictive system is the task of analyzing the original data set. The next task is to process the data according to the purpose and objectives of the predictive system. These two tasks are often not given enough attention and, as a consequence, the developer does not get the desired result as a result of building the system. This paper discusses methods and algorithms for data analysis and processing that can help in building a predictive system. The data set from the machine learning competition "ASHRAE - Great Energy Predictor III" is used as input data. The analysis phase focuses on constructing graphs and drawing conclusions from them. The paper shows how to use graphical information to find anomalies in the data and eliminate them. Examples of graphs that provide information useful for building machine learning models are given. The data processing phase describes the transformations performed on the data. It considers the transformations that lead to positive results as well as those that lead to negative results. [ABSTRACT FROM AUTHOR]

In the present paper we consider a phase transition in a viscous liquid in a solid skeleton near a single pipe filled with hot water. We suppose that the tube itself is part of a solid skeleton. First, we consider this physical process at the microscopic level (the characteristic pore size ε' is approximately 5-20 microns) governed by Stokes equations for incompressible viscous liquid coupled with heat equations. We also assume that the liquid in the frozen state becomes the part of the unmoved solid skeleton. Note that the boundary between the solid and liquid parts of the pore fluid is unknown (free boundary) and must be found together with the solution to the Stokes equations. The suggested mathematical model at the microscopic level is physically correct, because based on the classical Newtonian continuum mechanics. But any physically correct mathematical model at the microscopic level is practically useless due to its average size. Indeed, for the numerical implementation of any such model, a step in spatial variables of several microns is required. On the other hand-side, the problem must be calculated for domains of several tens meters. No modern supercomputers or cluster computing systems are yet capable of such computations. To make it practically valuable, we must use homogenization method, which is, roughly speaking, the mathematically rigorous approximation of the microscopic mathematical model in consideration by some macroscopic mathematical model. This part will be done in the next publication. [ABSTRACT FROM AUTHOR]

Phase change material (PCM) has attracted much interest in thermal energy storage (TES) applications due to its large heat storage capacity. The major drawback of PCM is the leakage of container, attributed by volume change during phase transition. Thus, the aim of this work is to produce form stable phase change material (FSPCM) with no leakage. FSPCM was prepared by encapsulation of myristic acid (MA) into the nitrile rubber (NBR) latex through dip coating. The performance of FSPCM was evaluated by using leakage test and the percentage of mass loss of MA after heating was calculated. PCM coated with 60% total solids content (TSC) of NBR latex shows no sign of leakage on the litmus paper. The percentage mass loss of FSPCM after thermal cyclic test was 0.46%. Thus, produced FSPCM has potential to be utilized in TES applications. [ABSTRACT FROM AUTHOR]

Rural settlement is an integral part of human shelter, which is generally organized in an organic form, in which groups of people cluster in a community, whose large proportion of the human population survives on agriculture and related professions. With the course of fast pace development, the villages are engulfed by towns and cities. Their agricultural lands are either acquired for a handsome ransom or occupied by builders by paying a huge sum of capital to the landlords. Here comes the transition phase, where traditional living styles take place in an urban environment that neither remains rural any more, nor adopts completely urban living styles. As a result, these peri-urban villages, not only lose their identity, but also fail to generate employability. So villagers migrate to metropolitan cities. This is the need of the hour to work on the rural renaissance, economic, cultural, well-being, and social sustainability on a priority basis, in selected prototype. This paper addresses the research gap that can be bridged with a multidisciplinary approach, in which the experts from all necessary disciplines shall coordinate on one platform and work on the overall well-being with smart usage of digital methods that suggest smart solutions to achieve sustainable village life and lifestyle, as well as restore its past glorious identity to secure a place in the smart village mission. [ABSTRACT FROM AUTHOR]

The paper considers laboratory experiments on unilateral freezing of samples of dry and wet sand. Freezing was carried out in the refrigerator under the influence of a cooling thermal plate from above. Thermometry of frozen sand samples was performed. As a result, the propagation velocity of the cold wave in the samples, the movement of the freezing front and the duration of the phase transition are estimated. Mathematical modeling of the sample cooling process was also performed. [ABSTRACT FROM AUTHOR]

Actuation is essential for the development of micro/nano electro-mechanical systems and the use of shape memory materials can be a solution for such a need. These materials exhibit structural phase transformation which is associated with changes in the thermo/magnetic/mechanical properties that can be used to control the actuation in various architectures. The magnetron sputtering deposition of films from such materials allows the generation of simple and complex architectures that can be used for micro and nanoactuation. This paper details several solutions to generate micro/nano actuation in bimorph and more complex architectures, and the way to control the actuation profile as a function of the phase transformation degree in the film. [ABSTRACT FROM AUTHOR]

Shape memory alloys (SMAs) are materials that both industry and research are interested in. SMAs are materials that, after a seemingly irreversible deformation, can return to their original shape. This alloy has poor yield strength when heated below its transformation temperature and will simply deform into any new shape that it can retain. SMA changes its crystal structure and returns to its original shape when heated above its transformation temperature. Because of their superior properties such as shape memory effect (SME) and pseudoelasticity, which are related to the specific way the biocompatibility, phase transformation temperatures, corrosion resistance, high wear resistance, and high strength, SMAs can be utilized in a variety of applications. This paper focuses on the features of SMAs, such as shape memory effect and superelasticity, as well as their types, fabrication processes, and the most significant applications. [ABSTRACT FROM AUTHOR]

Aluminum-steel clad composites are used as structural elements in car bodies and chases as well as in the chemical industry due to a combination of high strength of steel, low density of Al and high corrosion resistance of both materials. An important parameter influencing mechanical properties of the composite is the microstructure of the bonding region between Al and steel layer. During manufacturing of the final product, clad sheets can be subjected to elevated temperatures which enhance diffusion between the metals. As a result, a brittle intermetallic phase, deteriorating the bond strength between steel and aluminum, forms at the interface. This paper focuses on study of the interfacial microstructure in a twin-roll cast Al-steel clad strip and its evolution during in-situ annealing in transmission electron microscope. Due to isochronal annealing above 500 °C, Al5Fe2 phase forms at the interface. Nucleation centers formed at the beginning of heating experiment expand and form continuous layer. The kinetics of the growth follows the parabolic law typical for diffusion-controlled phase transformations. [ABSTRACT FROM AUTHOR]

We had introduced a microscopic technique to obtain heat capacity peaks near first-order phase transitions in polycrystalline phase change materials (PCMs). Such PCMs are composed of a large number of segments or grains, so that the total heat capacity of a PCM is a double average of heat capacities in the individual grains. One average is over surface (or boundary) effects occurring due to interactions of grains with their surroundings, while the other average is over grain sizes. Using this approach, we were able to derive a formula for heat capacity peaks and use it to very accurately fit experimental data for three selected PCMs measured by adiabatic scanning calorimetry. The fitted values of the phase change temperature for these three PCMs were not convincing, however. In this paper we argue that the reason for this controversy stems from too a crude approximation of surface effects that was used originally. Therefore, here we propose an improvement of our technique by suggesting a more appropriate approximation that still leads to as accurate fits as the original one. We illustrate this for one of the three PCMs. [ABSTRACT FROM AUTHOR]

The fibre-reinforced composite structural members play an essential role in enhancing the strength-to-weight ratio of the structure. Smart reinforcing fibres like Shape Memory Alloy (SMA) provide an additional feature of adaptive stiffness to the structure. In this paper, SMA wire-reinforced epoxy resin composite is analyzed for change in natural frequency with respect to change in transformation temperature of SMA wires to reveal the difference in stiffness of composite beam, which is a function of change in transformation temperature from martensite to the austenite phase. The numerical study is carried out using FEA software, and the experimental validation of the same is completed. The natural frequency shift is predicted by measuring the natural frequencies of the composite for free-free boundary conditions at different transformation temperatures. The significant change in the natural frequency of composite is observed during the shift in transformation temperature, and the FEA results are close to experimental results with reasonable accuracy; thus, the proposed composite provides adaptive stiffness. [ABSTRACT FROM AUTHOR]

The crystalline sample of PbNb2O6 (Lead meta niobate or PN) was grown by solid-state reaction method. The material crystallizes in an orthorhombic structure at room temperature and its phase transition temperature was confirmed by hysteresis loop studies reported in our previous paper. The dielectric relaxation properties are investigated here for this material, in a temperature range from 27°C to 600°C in the frequency range (10 – 106 Hz). A supportive study of micro-structural features of the sample has been reported to confirm the mechanism of dielectric relaxation processes and relaxation kinetics. It is concluded that the dielectric relaxations occurring at low frequency are related to the presence of space charges in association with vacancies, which are trapped at the grain boundaries. [ABSTRACT FROM AUTHOR]

Many metals and alloys have a complex of mechanical properties that ensure their wide application in engineering, in particular as structural materials. This is, first of all, a combination of high plasticity with significant strength and resistance to deformation, and the ratio of these properties can be regulated in a large range using mechanical and thermal treatments of metals, as well as the production of alloys of various compositions. The structural metal materials and alloys used in engineering are polycrystalline. Their mechanical properties are practically isotropic and may differ significantly from the properties of single crystals. In this paper, the crystal structures, strength and plastic properties of iron-manganese-based alloys, as well as alloys alloyed with silicon, are determined. All experiments were carried out on the X-ray installation "dRone", at the Central Research Institute of Ferrous Metallurgy named after I.P. Bardin. Dilatometric studies to determine the temperatures of direct and reverse martensitic transformations, the Neel temperature - the temperature of the magnetic phase transition were carried out on the quartz direct dilatometer "Sinco-Rico" and the German dilatometer "Linsay". [ABSTRACT FROM AUTHOR]

It is sixty years since Cyril Stanley Smith's seminal paper describing the effects of shock loading on the structure / property behavior of metals. While numerous experimental observations have fostered the correlation of post-shock microstructural parameters, such as dislocations, point defects, deformation twins, shock-induced phase products, etc., with particular shock parameters, quantitative predictive capability of the defect generation and damage evolution in materials subjected to dynamic loading has yet to be realized. Broadly based defect generation/storage phenomenology presenting a unified view of the material structure/property aspects of shock-wave deformation for a wide range of crystal structures has proven very difficult. However, changes in design and manufacturing paradigms applied to events dominated by dynamic-loading processes have placed increased emphasis on developing physically- based predictive materials models of shock effects on materials as well as amazing innovations in in-situ shock diagnostics. In this paper, a survey of the evolution in the state-of-our-understanding of defect generation and damage evolution is discussed and thoughts on the evolving capabilities to move shock / dynamic behavior of materials research from observation to design and control is presented. Examples of how utilizing "real-time", post-mortem, and "in-situ" experimental approaches together are needed to facilitate quantification 4D processes during shock-wave loading including dislocation / defect generation, shock-induced phase transitions, and damage evolution and spallation. [ABSTRACT FROM AUTHOR]

The lap joint of Zincalume G550 steel is welded by Metal Inert Gas (MIG) welding and ER70S-6 filler wire. 16.5 – 17.5 v of welding voltage and 3 – 4.5 m/min of wire-speed are set in parameters under the 70 A of constant welding current. The welded specimens were cold-mounted and cut with a cutting machine and the cross-section of the joints was ground with three different abrasive papers (220,1000,2000) and etching with Ferric Chloride (FeCl3). The microstructure of the joint surface is investigated. The fine (at FZ) and coarse grains (at HAZ) are identified clearly. In experimental testing, it can be seen that high welding voltage and low wire speed produced high heat energy, which can be led to the creation high volume of perlite structure in the weld zone and the grain size of the HAZ (heat affected zone) was much bigger than FZ (fusion zone) during the MIG process. The welding voltage is a direct relationship with forming microstructure that the phase transformation increases when the welding voltage increases. However, low wire speed can be expanded the size of the weld region where the fine grains are observed. In the FZ, the perlite structure (a-Ferrite and cementite) moved between the FZ and the HAZ, and the cementite grain much formed under the high-temperature end of the FZ. [ABSTRACT FROM AUTHOR]

The paper presents the study of the process of deformation-induced γ → α-transformation in TRIP-steel and its effect on the strain-hardening coefficient at the macroscopic level. It is shown that a phase transformation starts with the propagation of Luders bands during the pseudo-plateau, when the strain-hardening coefficient is constant. The boundaries of Luders bands are switching autowaves of localized plasticity. After the annihilation of switching autowaves in the samples in the austenitized state, the phase transformation continues with the movement of deformation fronts of the Portevin–Le Chatelier bands, which are excitation autowaves. In this case, the strain-hardening coefficient increases to a maximum value and then decreases up to fracture. The nucleation and propagation of phase transformation fronts is confirmed by magnetic measurements. After the transition to the stage where the hardening coefficient decreases, the γ → α' phase transformation decays and is no longer the predominant mechanism of plastic flow. [ABSTRACT FROM AUTHOR]

In the paper using the molecular dynamics method, several combinations of interatomic potentials are analyzed to describe the interaction of elements of a multicomponent Al-Cu-Ni alloy. The possibility of describing martensitic transformations proceeding under conditions of thermomechanical action was investigated. The studies made it possible to construct a physically correct model of the Al-Cu-Ni alloy and to analyze some regularities of structural transformations occurring in it under mechanical action and heating. The constructed model can be used for further research using a numerical experiment. [ABSTRACT FROM AUTHOR]

In this paper, we develop the theory of nucleation and evolution of crystals during the intermediate stage of phase transformation processes in metastable melts and solutions with allowance for the Gibbs-Thomson and attachment kinetics effects. An exact analytical solution of non-linear model equations is found in a parametric form. It is shown that the distribution function represents a bell-shaped curve moving with time, and the liquid metastability reduces with time as a result of the evolution of a polydisperse ensemble of crystals in a supercooled (supersaturated) system. [ABSTRACT FROM AUTHOR]

In this paper we investigate the Ising model on Z² with competing interactions. In this model we consider J1 as horizontal interactions and J2 as vertical interactions where J1,J2 > 0. We prove that this model can reach a phase transition. Onsager considered the case where horizontal interaction parameter J1 and vertical interaction parameter J2 are different. For any fixed J1 and J2, he showed that below a critical temperature Tc which depends on J1 and J2, phase transition occurs using some matrix transfer method. However in this paper we will prove the existence of phase transition using contours methods introduced by Sinai. We will show that there exists a ß0 > 0 such that for ß > ß0 there exist at least two limit Gibbs distribution which leads to the phenomena of phase transition. [ABSTRACT FROM AUTHOR]

The most prominent failure in electronic devices is due to excessive heating of the device during its operation. And the modern trend of miniaturization of electronic devices with better performance and features further extends the need for a proper cooling system. The phase change material (PCM) cooling technique is one of the most economical passive cooling methods which avoids mechanical vibration of the cooling system and provides stable cooling with repeated uses. This review paper presents the thermo-physical properties of commonly used PCMs and different types of thermal conductivity enhancers (TCE) for electronic devices. The findings of this literature consisting of both experimental and numerical works can be used as a guideline for future researches in this field. Heat transfer enhancement in PCM can be achieve using fins, porous media, mixing with carbon additives, microencapsulation of PCM, and by adding nanoparticles. For heat sink with fins, the volume fraction of the PCM and TCE is found to be directly affecting the performance of the cooling system. Also, distributed pin fins, the pattern of arrangement, shape, and size of the fin affects the heat transfer to the PCM. Microencapsulation also increases the heat transfer surface area of PCM. However, the selection of shell material and the core material is important to obtain the targeted thermal properties. Also, metal and metal oxide nanoparticles can significantly increase the heat conduction and diffusion capacity of the PCM. But, each of these enhancement methods has certain demerits which constantly required to be addressed to achieve a more efficient cooling system for modern electronics. [ABSTRACT FROM AUTHOR]

International Temperature Scale-1990 (ITS-90) is formulated based on various phase transition temperatures of high pure substances to cover the temperature range from 0.65 K to 1357.77 K (-272.5 °C to 1084.62 °C), where kelvin is defined on triple point of water (TPW) at 273.16 K and the higher defined fixed point is freezing point of copper at 1357.77 K. To extend the temperature scale at higher temperatures, metal-carbon eutectic fixed points are extensively being developed as the reference standards upto 3000 °C for thermometry and radiometry applications. The assignment of the eutectic melting transition temperatures to these metal-carbon eutectics is challenging as the melting plateaus are not as flat and wide as the conventional high pure metal fixed points. This paper presents the method to determine eutectic melting transition temperature by calculating inflection point for Fe-C and Co-C eutectic fixed point cells developed at CSIR-NPL, the national metrology institute (NMI)of India. The noble metal Type-S thermocouple calibrated on ITS-90 fixed points was used to measure and determine the melting transition temperatures of Fe-C and Co-C cells, and the associated uncertainties in determination of transition temperatures were evaluated. [ABSTRACT FROM AUTHOR]

As well known, when many alkali halides, for example NaCl, KCl or RbCI, are subjected to high pressure, phase transformation take place in them with a marked decrease in specific volume and reconstruction of the crystal lattice from the NaC1-type to the CsC1-type structure (B1 to B2). This work is undertaken the effect of pressure on the crystal structure with incorporating effect of temperature for the first time. An effective interionic interaction potential (EIOP) includes long range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction upto second-neighbor ions within the Hafemeister and Flygare approach with modified ionic charge. In this paper effect of temperature on phase transition make the EIOP model more suitable for calculating B1 to B2 phase transition. [ABSTRACT FROM AUTHOR]

The paper considers the change in the volumetric gas content, the formation of hydrate and the dynamics of pressure waves during its propagation in a channel with a variable cross-section containing water and a hydrate-forming gas Freon-12, and also considered the case of variable volumetric gas content in the channel during this process. Initially bubbly liquid is under pressure P0. Further, the pressure in the system suddenly rises to the value of Pe, after which a pressure wave of a stepped profile propagates through it to the creation conditions for the hydrate formation during its propagation in a narrowing channel was shown, without taking into account the processes of fragmentation of gas bubbles and the presence of surfactants. Also shown is the change in the amplitude of the pressure wave due to the formation of gas hydrate. In addition to changing the geometry of the channel, the paper also considers the case with a change in the volumetric gas content, due to the fact that the liquid increases its acoustic elasticity. The intensity of the gas phase transition in the work is described on the basis of the theory of nonequilibrium phase transitions in vapor-liquid systems. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics possess polarization under stress and ferroelectric is a subcategory of piezoelectric which possess spontaneous polarization, phase transition, permittivity, electrical and optical characteristics beneficial for energy storage devices, capacitors, memories, sensors, generators and numerous other applications. Perovskite is the most important and appreciable class of ferroelectrics having structure 퐴퐵푂3. Here we described the structure, formation and application of some perovskites [e.g퐵푎푇푖푂3(BTO), 퐵푎(푆푟푥푇푖1−푥)푂3(BST), 푆푟푇푖푂3(STO), 푃푏푇푖푂3(PT), 푃푏(푍푟푥푇푖1−푥)푂3 (PZT)] which exhibits piezo, pyro and ferro-electricity. In this paper we will discuss the use of these perovskite structure in the fabrication of thin and thick film form by sol-gel synthesis, spin coating, chemical solution decomposition, sintering and milling utilized in detection of gas, light,humidity, temperature and pressure sensor-based application in detail. [ABSTRACT FROM AUTHOR]

In this paper we have investigated the Bianchi type-II cosmological model with variable parameters in the frame work of modified f(R,T) gravity theory as suggested by Harko et al. (Phys. Rev. D, 84:024020). As we know that the effect of space-time curvature upon phase transition is an expanding universe. In this communication we have constructed a cosmological model of the universe by taking suitable assumptions along with string in presence of magnetic field. It is to be noted that our procedure for solving the field equations is different from other authors as we have consider the time dependent deceleration parameter (DP), it means that the universe which was decelerating in the past is accelerating at present time. We found that the universe is decelerating for q>0 and accelerating for-1q≤q<0, which shown signature flipping. [ABSTRACT FROM AUTHOR]

Computer modeling of crystal growth processes is often associated with complex numerical calculations. Results of such calculations cannot always be predicted. In some cases, features of mathematical methods of calculation in conjunction with assumptions of mathematical models can lead to the appearance of unexpected results. Such results on the one hand will be correct from a mathematical point of view, but on the other hand they will not have physical justification and experimental confirmation. Obviously, in such cases it is necessary to carefully process the results obtained taking into account the physical meaning and to avoid false conclusions. And it is especially important to take this into account in the case of large-scale high-performance simulations. Earlier, high-performance computational algorithm for the modified phase field crystal model (MPFC) of crystal growth were formulated and the results of some three-dimensional simulations are obtained. In current paper we present some unstable results of simulations by the MPFC and discuss such a phenomenon. [ABSTRACT FROM AUTHOR]

The paper is related to the investigation of scoliosis. To choose a proper way of surgical interference in severe cases, one should predict the future evolution of the spine. For this purpose, we suggest a mathematical model based on using of the nudged elastic band method (NEB) from phase transitions physics. An example of the method application to the model of three-vertebra system is considered. [ABSTRACT FROM AUTHOR]

In this paper we investigate the problem of phase transition for Ising model on a semi-infinite Cayley tree of third order with inhomogeneous left, middle and right parameters describing the strength of the interactions between left, middle and right nearest-neighbors respectively. We produce a recurrent equation that describes a limit behavior of the sequence conditional Gibbs measures and prove that if at least two of the parameters are positive one can reach phase transition. [ABSTRACT FROM AUTHOR]

In the last few decades the alkali halides emerged as crystals with useful applications and their high-pressure behaviour is the most intensively studied subject in high-pressure physics/chemistry, material science, and geosciences. Most alkali halides follow the B1 (NaCl-type)→B2 (CsCl-type) phase-transition route under pressure. In the present paper, we have investigated the characteristics of structural phase transition that occurred in Lithium Florid compound under high pressure. The transition pressure of B1-B2 was calculated using an effective interionic interaction potential (EIOP). The changes of the characteristics of crystals like, Gibbs free energy, cohesive energy, volume collapse, and lattice constant are calculated for the B1 and B2 structures. These data were compared with the available experimental and theoretical data. [ABSTRACT FROM AUTHOR]

This paper presents the synthesis of transparent thin films of zirconium oxide (ZrO2) deposited on glass substrates by sol-gel dip coating technique. Synthesized films were characterized for different annealing time and withdrawal speed. Change in crystallographic properties of thin films was investigated by using X-ray diffraction. Surface morphology of transparent thin films was estimated by using scanning electron microscope. [ABSTRACT FROM AUTHOR]

Material extrusion-based additive manufacturing, strictly speaking of the Fused Filament Fabrication (FFF), is characterized by using a thermoplastic polymer in form of a solid filament as a built material. The filament partially melts inside of a heated hotend and is subsequently extruded under the pressure generated by the filament feeding force of the feeding rollers. The processes in the heated extrusion channel are complex and difficult to model, as the melt properties are a nonlinear function of temperature and shear rate. Moreover, there is a phase transition from solid filament to liquid melt. In this paper, the required feeding force and resulting extrudate temperature at the nozzle outlet at different feeding rates, liquefier temperatures and nozzle geometries of two acrylonitrile-butadiene styrene (ABS) and polypropylene (PP) materials were investigated. For a better understanding of the melting process in the hotend, the degree of melting of the strands was determined via dead-stop experiments at selected operating points. Two process windows could be identified: At low feeding rates, the feeding force increases linearly with increasing velocity, and at a certain point, the force increases rapidly and fluctuates. The melting investigations showed that this is related to the increasingly unmolten material reaching the nozzle outlet. The semi-crystalline PP showed a smaller processing window for stable flow compared to ABS and lower extrudate temperatures due to its differentiated cp progression at the phase transition. Based on the experimental studies, Computational Fluid Dynamics (CFD) simulations were performed to predict the pressure and temperature distributions inside the channel. For modelling the shear-dependent viscosity the Carreau model was used, while the temperature dependency was described by a jump function with a solid viscosity of 106 Pa.s. It is shown that the numerical model can predict the feeding force with good accuracy and represent the change between process windows at increasing speeds. [ABSTRACT FROM AUTHOR]

This paper reveals the structural information of lithium hydride (LiH) at high pressure. The model potential incorporate coulomb interaction potential, short range interaction and van der Waal's attraction energy within the Hafemeister and Flygare approach and the potential term as effective interionic potential model. Values obtained via this technique for LiH, revealed successful phase transition from B1 or NaCl to B2 or CsCl, The estimated transition pressure is 200 GPa, which is quite consistent with the previously available data from different theoretically techniques. [ABSTRACT FROM AUTHOR]

In the present paper, we have investigated pressure dependent structural phase transition and associated volume collapse at transition in Iron silicide (FeSi) through effective inter-ionic potential method. It has been shown that by applying an effective interionic interaction potential, which includes the long-range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction up to second neighbor ions within the Hafemeister and Flygare approach provide successful evaluation of equation of state for change in volume with respect to the applied pressure. The phase transition pressure (Pt) at 13GPa is reported for FeSi, which is consistent with the available experimental data. This transition corresponds to transformation of B1(NaCl) type structure to B2(CsCl) type structure and is a first order phase transition. This first order phase transformation showed a volume collapse of FeSi is 10.2% at 13GPa. In addition, we have also predicted pressure dependent structural phase transition and volume collapse of 1wt% silicon doped Iron alloy (Fe0.91Si0.09) is 10.91% at 16 GPa. [ABSTRACT FROM AUTHOR]

Experimental study on stopping power of ferroelectric Tryglycine Sulphate (TGS) single crystal for 24.779 MeV protons was carried out as a function of the temperature of TGS with an accuracy of 0.05%. The stopping power of the TGC crystal shows broad valleys in ferroelectric region when the proton beam is moving along the ferroelectric b-axis (010). The fluctuations with peak-peak variation of 0.3% - 0.6% for proton beam near the Curie temperature TC is observed. This variation in the ferroelectric region cannot be contributed to the dielectric constant of the medium. The electric field and the localized temperature due to passage of proton beam may cause the switching and pining of the domains. The domain switching time τs depends on the transverse electric field and sample thickness. The thermal spike model is used to estimate the increase in the localized temperature due to passage of 24.779 MeV Protons in ferroelectric TGS crystal. In this paper, the experimental method of measuring stopping power of TGS crystal for proton beam, interpretation of the results in terms of (i) increase in localized temperature of the crystal sample using thermal spike model, (ii) the transverse electric field developed in the crystal sample and (iii) the domain switching time to account the observed experimental fluctuations in stopping power of TGS crystal for proton beam is discussed. [ABSTRACT FROM AUTHOR]

Precipitated calcium carbonate (PCC) is also known as synthetic calcium carbonate. In this paper, PCC was synthesized from carbide lime, which is the by-product from acetylene gas industry. The method used to produce PCC from carbide lime waste was ionic sucrose precipitation technique. The experiments were performed by varying the stirring rate. In this technique, carbide lime was first dissolved in ionic sucrose solution and then chilled at 10 °C for 24 hours before carbon dioxide gasses was introduced into the solution. The carbonation and precipitation process was took place and PCC was formed. The PCC was further filtered to obtain the solid PCC. The sample was then further characterised by using FESEM and XRD to determine the morphology and to identify the phase that exists in the synthesized compound respectively. The XRD and FESEM results clearly shown that the PCC obtained has mixed phases of calcite and vaterite, with mixtures of spherical and irregular shape morphologies formed. The irregular shapes corresponded to vaterite formation, meanwhile spherical shapes corresponded to calcite formation. [ABSTRACT FROM AUTHOR]

Measurement of the surface residual stress in a flat hot rolled steel strip using strain gauge method is considered in this paper. Residual stresses arise in the flat strips when the shear cut and laser cut is applied. Bending, twisting, central buckled and edge waviness is the common defects occur during the cutting and uncoiling process. These defects arise due to the non-uniform elastic-plastic deformation, phase transformation occurring during cooling and coiling-uncoiling process. The residual stress analysis is very important because with early detection it is possible to prevent an object from failure. The goal of this paper is to measure the surface residual stress in flat hot rolled strip using strain gauge method. The residual stress was measured in the head and tail end of hot rolled strip considering as a critical part of the strip. [ABSTRACT FROM AUTHOR]

This paper presents a procedure for the implementation of control algorithms for hardware-bit compatible with the standard IEC61131-3. The described transformation based on the sets of calculus and graphs, allows translation of the original form of the control program to the form in full compliance with the original, giving the architecture represented by two tick. The proposed method enables the efficient implementation of the control bits in the FPGA with the use of a standardized programming language LD. [ABSTRACT FROM AUTHOR]

This paper presents an overview of bainite transformation in low carbon steel, which is alloyed with some alloying elements such as Mn, Si, Cr. The article also presents an overview of the transformation mechanism of this steel group. From the synthesis of research works, the influence of alloying elements on steel's microstructure and mechanical properties has been determined. And the final article, the bainite microstructure of CMnSi steel was found when deforming and heat treatment. By OM, the bainite structure was found. The article presents the influence of the deformation process on the microstructure and mechanical properties of low carbon alloy steel, which heat treatment by TBF processing. The samples are deformed at different levels: 20%, 40%, and 80%. The research results show that: When the sample was deformed with 80%, the highest strength was 800MPa, the highest elongation was 36%, the product between the strength and the elongation (Rm*A) was the highest: 28774MPa*%. This alloy deformed at a level of 80%. The content of austenite in this alloy's microstructure was the highest, about 16%; the content of ferrite was 52%, with the average particle size of ferrite being 6.4 µm; the particle of residual austenite was 2 µm. The microstructure results have contributed to improving the mechanical properties of steel. The phase that improved the mechanical properties of this alloy had grain size and dispersed. [ABSTRACT FROM AUTHOR]

In this paper we consider Ising models with competing interactions defined on semi-infinite Cayley tree of second order. Phase diagram of such models contain new modulated phases, in addition to the expected paramagnetic and ferromagnetic phase. The aim of this paper is to select phases of these models with competing interactions on Cayley tree which exhibit phase transitions and at the same time can be solved exactly. [ABSTRACT FROM AUTHOR]

A phase change material (PCM) is a substance which releases/absorbs sufficient latent heat of fusion at phase transition to provide useful heating/cooling. Hence, they act as excellent energy storage devices. In most of the PCMs, the phase transition happens at the solid-liquid interface. Hence, the phase transition temperature will be the melting point of the PCM. For a PCM to work efficiently, the difference between the melting temperature and solidification temperature should be as low as possible. However, in most of the PCMs, it is observed that solidification starts at a temperature much below the melting point. This phenomenon, known as sub-cooling, leads to significant loss in the storage/retrieval of latent energy which is undesirable. This paper reviews the various methods that has been investigated to overcome the problems associated with sub-cooling. The various methods discussed include – addition of appropriate nucleating agents of similar crystal structure as that of the PCM, cold finger technique and application of surface roughness on the walls containing the PCM, ultrasonic irradiation, application of dynamic pressure, cavitation and electrical means. Experiments conducted by researchers and their corresponding results have been discussed. [ABSTRACT FROM AUTHOR]

This paper presents a physical and mathematical model that has been developed in the framework of the approach used in the computational mechanics of materials. The model is designed to enable the study of the patterns of deformation and fracture of ceramic composites with a transformation-hardened matrix at the mesoscopic and macroscopic levels under intense dynamic loading. The influence of the loading rate on the formation of the fracture and energy dissipation fronts for composite materials based on the Al2O3-20%ZrO2 system is shown. Nonlinear effects in the considered composites under intense dynamic loading are associated with the processes of the self-organization of structural fragments at the mesoscopic level, as well as with the occurrence of martensitic phase transformations in the volumes of the strengthening particles. In this paper, specific destruction work is used as the main parameter that determines the contribution of each composite component to the destruction work. [ABSTRACT FROM AUTHOR]

This paper shows the effect of silicon on structural and phase transformations in aluminum-chromium powder compacts during heating in the ambient air at 500°C. Samples were obtained by pressing from a mixture of the powders. The studies were carried out by using X-ray diffraction and metallographic analysis, and measuring the weight gain of the samples. It was found that silicon additives (10–20 at %) block the reaction interaction of aluminum and chromium, that occurred in two-component mixtures (Al-Cr) at 500°C and prevent a significant volume growth of the compacts. [ABSTRACT FROM AUTHOR]

The paper has analyzed the results of studies of PMS oligodimethylsiloxanes with the indices: 30, 40, 50, 100, 400, 1000. The results of experimental studies have served as the basis for the assumption of formation of a continuous crystalline field during crystallization of oligodimethylsiloxanes, which affects the increase of kinematic viscosity. An analytical dependence of the relative pyroelectric coefficient on the logarithm of kinematic viscosity has been obtained. The obtained ratio was used as the basis for determining the parameters of oligodimethylsiloxane crystallization process of in an inhomogeneous temperature field at temperatures of the first order phase transition. [ABSTRACT FROM AUTHOR]

The paper presents the results of theoretical, numerical and experimental investigations of combustion and detonation initiation in heterogeneous poly-dispersed mixtures. The problems of fuel droplets atomization, evaporation and combustion and the non-equilibrium effects in droplets atomization and phase transitions were taken into account. The effects of droplets size non-uniformity and spatial distribution non-uniformity on mixture ignition and flame acceleration were investigated for strong and mild initiation of detonation: by a shock wave and spark ignition followed by deflagration to detonation transition (DDT). Peculiarities of jet injection and ignition in reaction chamber are studied. [ABSTRACT FROM AUTHOR]

Starting in January 2017, AMADEUS (www.amadeus-project.eu) is the first project funded by the European Commission to research on a new generation of materials and solid-state devices for ultra-high temperature energy storage and conversion. By exploring storage temperatures well beyond 1000 °C, one of the main objectives of the project is to create new PCMs (phase change materials) with latent heat in the range of 1000-2000 kWh/m3, an order of magnitude greater than that of typical salt-based PCMs used in concentrated solar power (CSP), along with developing advanced thermal insulation, PCM casing designs, and novel solid-state thermal-to-electric energy conversion devices able to operate at temperatures in the range of 1000-2000 °C. In particular, the project is investigating silicon-boron based alloys as PCMs and hybrid thermionic-photovoltaic (TIPV) devices for energy conversion. This paper describes the main project R&D activities and the results that have been attained during the first two years of the project. This includes the thermophysical characterization of Si-B alloys, the wettability and solubility analysis of said alloys with solid refractory materials, the numerical simulation of phase-change and heat losses through thermal insulation cover, as well as the realization of the two main proof-of-concept experiments: the TIPV converter, and the full latent heat energy storage system. [ABSTRACT FROM AUTHOR]

Microstructure evolves during different processes; and phase transformation is one of these processes. The importance of phase transformation in the microstructure formation causes that many analytical and numerical methods are applied for its modeling. The objective of present paper is further development of 2D hybrid model of diffusional phase transformations. Heat transfer and diffusion during the transformation are considering. The model is based on Lattice Boltzmann Method (LBM) and cellular automata (CA). Diffusion and heat flow are modeled by LBM, whereas the microstructure evolution by CA. The paper presents the modeling results of the growth of new phase that is determined by the differences of carbon concentration in the phases and overheating/overcooling considering the enthalpy of transformation. Examples of simulation results are presented in the form of images, graphs and distributions. [ABSTRACT FROM AUTHOR]

Phase transition in Molybdenum disulfide (MoS2) from 2H to 1T has attracted a considerable research interest in recent years due to its far exceeding unique potential applications. This paper describes the coexistence of 1T and 2H phases of MoS2 after microwave irradiation. The irradiation of microwaves on MoS2 can modify its structural and surface electronic properties. We have studied this behavior using X-ray diffraction (XRD), UV-vis (UV) spectrophotometer and scanning Kelvin probe microscopy (SKPM). A change in the contact potential difference of 2H-1T phase MoS2 has been observed. [ABSTRACT FROM AUTHOR]

In this work, bismuth oxide (Bi2O3) photocatalyst was prepared using nitrates of bismuth through a single step microwave method. These Bi2O3 photocatalysts were analysed by using various techniques such as XRD, Raman, UV-Vis spectroscopy and time resolved photoluminescence (TRPL) life time measurements. The Bi2O3 photocatalyst was formed with tetragonal structure in the as-prepared form and it was structurally transformed into a monoclinic phase with appropriate heat-treatment at 550 ᵒC. This was noticed as a phase transformation from β-phase (tetragonal) to α-phase (monoclinic structure) which has been confirmed by XRD and Raman spectroscopy analysis. The synthesized Bi2O3 photocatalyst with monoclinic phase was tested for the photocatalytic degradation of Rhodamine B (Rh-B) under Sun light irradiation and the results are discussed in this paper. [ABSTRACT FROM AUTHOR]

In this paper theoretical model for the synthesis of a gas hydrate in the secluded cell foam are proposed, and the case of the synthesis of a gas hydrate was considered. The problem of the phase transition (the Stefan problem) is considered in a one-dimensional formulation in the region occupied by the substance in the liquid phase and in the region occupied by the substance in the solid phase with a phase transition at the interface. [ABSTRACT FROM AUTHOR]