Pressure Melting Research Articles

Study on the Flow, Foaming Characteristics and Structural Strength of Polypropylene Structural Foam Injection Molding by Innovative Nitrogen and Molten Plastic Mixing Mechanism.

Plastic foam molding methods include thermoforming, extrusion and injection molding. Injection foam molding is a one-time molding method with high production efficiency and good product quality. It is suitable for foamed plastic products with complex shapes and strict size requirements. It is also the main method for producing structural bubbles. In this investigation, we developed a structural foam injection molding technology using the gas supply equipment connected to the unique plasticizing mechanism of the injection machine and studied its influence on the specimens' melt rheology quality and foam structures. In the experiment, the forming material was polypropylene (PP), and the gas for mixing/forming foaming characteristics was nitrogen (N2). Additionally, in order to observe the rheological properties of N2/melt mixing, a melt flow specimen mold cavity was designed and the change in the melt viscosity index was observed using a melt pressure sensing element installed at the nozzle position. With the nitrogen supply equipment connected to a unique plasticizing mechanism, the mixing of gas and molten plastic can be achieved at the screw plasticizing stage, where the foaming effect is realized during the melt-filling process due to the thermodynamic instability of the gas. It was also found that an increase in N2 fill content increased melt fluidity, and the trend of melt pressure and melt viscosity index showed that the higher the gas content, the lower the trend. The foaming characteristic depends on the gas thermodynamic instability and the pressure release, so it can be seen from the melt fill path that, the greater the pressure near the gate, the lower the foaming amount and the internal structure (SEM) after molding; the farther from the gate, the greater the relative increase in the foaming growth/amount. This phenomenon will be more obvious when the N2 fill content is increased.

Reassessing a glacial landscape developed during terminal glaciation of the Late Paleozoic Ice Age in Uruguay

Whalebacks, roche moutonnées, and S-forms carved on Ediacaran granitoids near Cerro de las Cuentas, Uruguay, along with overlying diamictites, siltstones, and sandstones displaying soft-sediment grooved and striated surfaces in the Pennsylvanian San Gregorio Formation, record the glacial to post-glacial transition in the linked Norte, southern Paraná and Chaco-Paraná basins of Uruguay, Brazil, and Argentina respectively. Early authors reported these features resulted from subglacial abrasion and deposition as lodgement tills and glaciotectonites. Our re-examination reveals a nuanced setting with changing ice thicknesses, subglacial kinematics, and ice proximal glaciomarine dynamics associated with advance and retreat of an ice stream, or multiple advances of the Uruguayan Ice lobe, during glaciation of the Late Paleozoic Ice Age (LPIA) in these basins. The preserved landforms indicate temperate glacial conditions. Whalebacks formed under 1.6 to 2.5 km-thick ice and likely formed when the lobe extended across the Uruguayan and Rio Grande do Sul shields into the adjacent Paraná Basin. Previously unidentified m-scale roches moutonnées cut into one whaleback developed under thinner ice where reduced basal pressure allowed for the opening of air and water-filled cavities, thus facilitating quarrying on the lee side of basement bumps. S-forms provide additional evidence for the occurrence of subglacial waters, indicating that the basal ice was at or above its pressure melting point. The lower meter of the overlying strata consists of interstratified trace fossil-bearing, laminated siltstones; thin-bedded diamictites; and current-rippled sandstones. Trace fossils belonging to the Mermia ichnofacies within the basal siltstones, as well as acritarchs in the overlying siltstones, suggest that these sediments were deposited in ice-proximal subaqueous settings with contributions from meltwater discharge. Graded siltstone laminae suggest settling from suspension likely from meltwater plumes, while thin-bedded diamictites were deposited either as debris flows or as two-component sedimentation with fines settling from suspension and coarser particles introduce as iceberg-rafted dropstones. Current-rippled sandstones indicate the occurrence of underflow currents. Soft-sediment troughs, grooves, and striations cutting these sediments display curved and sinuous paths with some features oriented perpendicular, and one oriented opposite to the overall trend. They contain marginal and terminal berms typical of iceberg scour marks suggesting transit across the area by icebergs calving from a tidewater ice front located to the SE.

Pressure melting of pore ice in frozen rock under compression

The pressure-melting effect of ice can lead to changes in the relative content of ice and unfrozen water in frozen rocks, as well as the pore structure, which will have a substantial impact on the mechanical behavior of frozen rocks. In order to study the pressure-melting effect of frozen sandstone, uniaxial compression tests were conducted at varying freezing temperatures, while changes in electrical resistance were recorded. The phase composition in pores was tested by nuclear magnetic resonance (NMR). The results indicate that: (1) The electrical resistance of saturated frozen rocks decrease rapidly in microcrack-compaction (M-C) stage and slowly in elastic deformation (E-D) and microcrack propagation (M-P) stages with the increase of strain, which is very different from oven-dried rock. (2) The average reduction rate of electrical resistance in M-C stage rises at 0 °C ∼ -4 °C, and remains constant at −4 °C ∼ -20 °C. (3) At 0 °C ∼ −4 °C, the free, capillary and part of adsorbed water in the rock are frozen. At −4 °C ∼ -20 °C, adsorbed water is frozen. Curvature induced premelting severely depresses the freezing point of water in microcracks, while, the stress concentration effect in microcracks induces pressure melting of pore ice. Therefore, we propose: (1) The pressure-melting effect of frozen sandstone occurs mostly in the M-C stage. (2) At −2 °C, the pressure-melting effect causes the melting of ice frozen by free and capillary water, and at −4 °C ∼ -20 °C, this effect leads to the melting of ice frozen by adsorbed water, rising the unfrozen water content, which may alter the mechanical behavior of frozen rocks.

A Novel Sensing Feature Extraction Based on Mold Temperature and Melt Pressure for Plastic Injection Molding Quality Assessment

Injection molding is one of the polymer molding methods. Product quality mainly can be affected by temperature and pressure. To observe the process of the melt forming in the mold, it is required to monitor the signal with the sensor. To achieve the purpose of robust molding, this research provides a new design-process window architecture based on machine learning of the injection product quality assessment. The process window is also known as the forming area map. The monitored value for defective products will be above or below the variable limit. The process is set to the center of this window so that any variation within the window will still result in an acceptable product. There are some potential problems in the current process. First, the conventional process window uses a small number of process variables as monitoring indicators, and it cannot provide stronger monitoring indicators. Second, most of the conventional process windows are 2-D and there are many monitoring windows, so the information that can be monitored is limited. Therefore, product quality cannot be effectively monitored without proper selection of important factors. Finally, the current process window can only provide information in the process and cannot make product quality prediction. In order to solve the above problems, a machine learning method is proposed to design the process window. The random forest classifier and regressor are used to predict the product quality. In order to improve the usability of the factor, the design of the proposed new variable is derived from the classical formula of thermodynamics (heat conduction). Using existing factors and proposing time-based feature changes can better represent the molding process as a whole. Based on the experimental results, the proposed variables can effectively increase the predictive performance of random forest model for quality assessment. The research results make a satisfactory result to the quality assessment of industrial injection molding. The accuracy of the prediction results is 100%. Moreover, it can be found from the 3-D process window that the data are very concentrated and can be clearly classified by the hyperplane, which is defined as the shortest distance between two clusters, and this space is the boundary of the process window. Therefore, compared with the past, the judgment boundary based on the random forest process window is no longer a simple boundary. Random forests can provide more accurate visualization boundaries.

A ring shear device to simulate cryosphere processes

We have developed a new cryogenic ring shear device at the University of Wisconsin–Madison to simulate cryosphere processes, with an emphasis on the physics of glacier slip. The device spins a ring of ice (inner diameter of 20 cm, outer diameter of 60 cm, height of ∼20–30 cm) at the pressure melting point over a rotationally fixed bed. The ice ring is spun at a prescribed velocity (range of ∼0.01–1000 m a−1) while the resistance to slip is measured. A ram at the base of the device applies a vertical load to the sample chamber to simulate the overburden pressure (range ∼5–915 kPa) felt at a glacier’s base. The sample chamber is constructed with transparent acrylic walls, allowing subglacial processes to be observed directly by a series of cameras. The entire device is housed in a large walk-in freezer. In the freezer, the sample chamber is submerged in a tub of temperature-controlled fluid that precisely regulates heat flux into the sample chamber, replicating in situ conditions and allowing for prolonged experiments that last weeks to months. This device can be used to study several of the most unconstrained physical processes that regulate glacier movement and, in doing so, greatly improve predictions of glacier contributions to sea-level rise.

High Pressure Melting Curve of Fe Determined by Inter‐Metallic Fast Diffusion Technique

AbstractThe heat extracted from the core by the overlying mantle across the core‐mantle boundary controls the thermal evolution of the core. This in turn leads to the solidification of the inner core in association with the exsolution of light alloying elements into the liquid outer core. Although the temperature (T) at the inner core boundary (ICB) would be adjusted to account for the effects of the light elements, the melting T of Fe places an upper bound at the ICB and it is a vital point in the thermal profile of the core. Here, we determine the melting T of Fe in the multi‐anvil press by characterizing the interface of Fe‐W interaction. Our data place a tighter constraint on the melting curve of Fe between 8 and 21 GPa, that is directly applicable to small planetary bodies and serves as an anchor for melting curve of Fe at higher pressure.

A non-linear viscoelastic material model with progressive damage based on microstructural evolution and phase transition in polycrystalline ice for design against ice impact

This study presents a nonlinear viscoelastic material model incorporating a progressive damage framework with an iterative algorithm for glacial/freshwater polycrystalline ice subject to compressive impact load induced by ice-structure interaction. The damage model accounts for microcracking, dynamic recrystallisation, pressure melting, and high-shear elastic failure with a pressure- and rate-dependent convex failure locus. The constitutive laws are written in Fortran and implemented as a vectorised user material (VUMAT) in Abaqus with three different numerical methods, Lagrangian FEM, coupled FEM-SPH, and ALE-FEM. The constitutive model together with the implemented numerical methods are validated against two different types of laboratory-scale physical tests, indentation of cone-shaped ice and triaxial creep. The proposed model implemented with the coupled FEM-SPH method enables simulation of the cyclic transition from solid-like intact ice to the fluid-like pulverised/granular substance, progressively extruded with viscous rheology.

Development of a methodical approach to set-up the injection velocity profile dependent on the part geometry

Abstract The injection volume rate is an important setting parameter of the injection moulding process as it determines local process parameters as melt front velocity, respectively, shear rate, pressure and temperature in the mould cavity. In order to avoid too low or too high melt front velocities, profiling of the injection volume rate during the injection is necessary dependent on the part geometry. However, the set-up of a volume rate profile at the machine is an iterative and subjective process so far. Therefore, a method is developed that determines a suitable volume rate profile based on the process simulation gaining a constant melt front velocity or melt front shear rate. A developed process model enables the transmission from simulation to the machine based on a volume rate balance in the screw antechamber. The simulative and experimental results show a good agreement of the cavity filling.

Effect of quercetin on the structure and oxidation resistance of polyphenylene sulfide fiber prepared by melt spinning

Polyphenylene sulfide fiber is easily oxidized at high temperature, thus vastly reducing its application range. In this study, polyphenylene sulfide/quercetin fibers were prepared via melt spinning. The effect of quercetin on the spinnability of the composite fibers was explored, and their cross-sectional morphology, crystalline properties, orientation, tensile properties, thermal stability and oxidation stability were investigated. At the quercetin content of 1.5 wt.%, particle agglomerates and some gasification, causing fluctuations in melt pressure, fiber breakage and poor spinnability, were observed in the polyphenylene sulfide matrix. The addition of quercetin can increase the crystallization temperature of polyphenylene sulfide, shorten its crystallization time, refine the crystalline particles therein, and improve the degree of fiber orientation. At the quercetin content of 1.0 wt.%, the tensile strength and elongation at break of composite fibers increased by 30.8% and 7.6%, respectively, as compared to those of pure polyphenylene sulfide fibers. Moreover, the decomposition temperature and the oxidation induction temperature at a 5% weight loss were 16.3°C and 13.4°C higher than those of the unmodified PPS fibers. The loss of strength of composite fibers subjected to oxidation for 240 h was only 18.4%. The X-ray diffraction results showed that the phenolic hydroxyl groups in the quercetin structure were able to capture free radicals generated during the oxidation of polyphenylene sulfide fibers, as well as inhibit the oxidative degradation reaction and improve the oxidative stability of the fiber. The oxidation resistance mechanism of composite fibers was also proposed.

Manipulation of the Martensitic Transformation and Exchange Bias Effect in the Ni45Co5Mn37In13 Ferromagnetic Shape Memory Alloy Films

The martensitic phase transition and exchange bias effect of the Ni-Mn-based ferromagnetic shape memory alloys (FSMAs) Ni45Co5Mn37In13 (Ni-Co-Mn-In) films are investigated in this paper. The martensitic transformation properties of the Ni-Co-Mn-In alloy target material are manipulated by the process of electric arc melting, melt-fast quenching, and high-temperature thermal pressure. The Ni-Co-Mn-In alloy films with martensite phase transition characteristics are obtained by adjusting deposition parameters on the (001) MgO substrate, which shows a significant exchange bias (EB) effect at different temperatures. With increasing sputtering power and time, the film thickness increases, resulting in a gradual relaxation of the constraints at the interface between the film and the substrate (the interfacial strain decreases as the increase of thin film thickness), which promotes the martensite phase transition. Between zero-field cooling (ZFC) and field-cooled (FC) curve obvious division zone, the decrease of exchange bias field (HEB) and coercive force field (Hc) with an increase in test temperature is due to ferromagnetic (FM) interaction begins to dominate, resulting in a reduction of antiferromagnetic (AFM) anisotropy at the interface. The maximal HEB and Hc reach ~465.7 Oe and ~306.9 Oe at 5 K, respectively. The manipulation of the martensitic transformation and EB effect of the Ni-Co-Mn-In alloy films demonstrates potential application in the field of information and spintronics.

Pulsed and Static Magnetic Field Influence on Metallic Alloys during Solidification

Electromagnetic methods can be used to affect the solidification of metallic alloys. Combined alternating and static (DC) magnetic fields can induce pressure waves in liquid metals in a contactless manner, refining grain structure, preventing component segregation, and dispersing added particles. Here, the possibility of using a pulsed magnetic field in combination with a DC magnetic field to improve the solidification structure of metals is investigated. This enables achieving higher pressure amplitude and liquid movement within the whole crucible volume at the same power consumption. This can be a prospective way to achieve a fine-grained and a more homogeneous microstructure of metallic alloys as well as disperse added particles. In this work, analytical description of the phenomena and numerical modeling of the pressure amplitude and melt motion has been performed. A series of experiments have been carried out to demonstrate the effect of such interaction on the solidified metal microstructure. It is found that a combination of pulsed and DC magnetic fields creates strong compression and expansion of the liquid metal. Metals solidified under such interaction exhibit finer grain structure in Sn-Pb alloy and improved TiB2 particle distribution in 6061 aluminum alloy.

The Meaning of Pressure for Primary Magmas: New Insights From PRIMELT3‐P

AbstractThis paper reports new software, PRIMELT3‐P, for computing the pressure and temperature range over which a primary basaltic magma was formed by adiabatic decompression and fractional melting of fertile mantle peridotite. The underlying model was developed to explore the meaning of magmatic pressure and its connection to the physics of mantle melting, melt extraction, and melt migration. We present a comparison of the results of the batch melting model FractionatePT3 (Lee et al., 2009, https://doi.org/10.1016/j.epsl.2008.12.020) and the new fractional melting model PRIMELT3‐P, each applied to basalts from various localities, with a particular focus on Hawai'i and Iceland. The unexpected result is that pressures for batch melting and fractional melting are quite similar across a broad range of potential temperatures, agreeing to within ±0.29 GPa (1σ) when applied to magmas that pass tests for derivation from peridotite sources. Although samples from both Hawai'i and Iceland yield a range of final pressures of melting, the minimum final pressure in each location coincides with independent geophysical constraints—the depth to the lithosphere‐asthenosphere boundary beneath Hawai'i and to the Moho below Iceland. These results clarify the meaning of primary magma pressure, but the concept remains complex. We suggest that computed temperature and pressure arrays arising from heterogeneous peridotite‐source primary magmas may reflect melt transport and mixing in a thermally zoned mantle plume with a complex network of branching melt channels that nucleate over a range of depths.

The capturing and decompression of melt inclusions in olivine and ilmenite megacrysts from the Monastery kimberlite, South Africa

Ilmenite and olivine megacrysts from the 89 Ma Monastery kimberlite (Kaapvaal Craton, South Africa) captured abundant and large melt inclusions containing quenched Si-Mg-rich melt, calcite, spinel, perovskite, phlogopite, and serpentine. Textural observations and 3D X-ray tomography of ilmenite and olivine megacrysts show melt inclusion shapes, sizes and distribution patterns indicative of melt capture during primary crystal growth near the base of the subcontinental lithospheric mantle (SCLM). Patterns supporting secondary melt injection along fractures or veins, such as planar arrays of melt inclusions, are absent. Melt inclusions in olivine, in some examples reaching the dimension of centimetres, likely were captured in skeletal voids forming in fast growing, up to decimetre-sized olivine megacrysts. These large melt inclusions commonly decrepitated, forming apophyses, radial fractures, and veins, along which residual volatile- and Si-Mg-rich melt was extracted. We attribute the decrepitation of melt inclusions in olivine to the rapidly increasing difference between the melt pressure in the inclusions, captured at mantle depth, and the decreasing confining stress to which the host olivines were exposed during magma ascent and after emplacement. In ilmenite, melt inclusions up to ∼ 6 mm in diameter remained commonly intact during the kimberlite ascent from its mantle source to the shallow crust. The quenched silicate melt in olivine- and ilmenite-hosted melt inclusions, in some places preserved as unaltered hydrous and CO3-bearing glass, shows systematic major element compositional variations that suggest that this melt formed by similar fractionation and depletion processes, irrespective of the hosting megacryst phase. Apparent modal variations in quenched silicate melt, calcite, and oxide contents suggest that the melt batches captured as inclusions in ilmenite and olivine either record different evolution stages in the megacryst magma, or document compositional heterogeneities in this magma at the time of megacryst growth.

Prediction of the melting curve and phase diagram for CaO using newly developed interatomic potentials

A comprehensive investigation of the melting curve and pressure–temperature (P–T) phase diagram for CaO, a candidate mineral in the Earth's lower mantle, is performed via atomistic simulations applying newly developed interatomic potentials. The efficiency and reliability of the new potentials under high temperature and pressure are verified with lattice dynamics, molecular dynamics, and first–principles approaches, where the fitting values of the potentials are extracted from the lattice parameters, elastic constants, and energy differences of rock–salt (B1) and cesium chloride (B2) phases in CaO. The melting temperatures of CaO with B1 structure at ambient pressure obtained from the single–phase method, void method, and two–phase method are 3080 K, 2775 K, and 2767 K, respectively. The structure and diffusion are evaluated by radial distribution functions, mean square displacements, and self–diffusion coefficients in the solid and liquid states for CaO. Simultaneously, the P–T phase diagram of CaO is calculated up to the core–mantle boundary pressure of 135 GPa, in which the Clausius–Clapeyron relation is introduced to determine the slope of the phase boundary between B1 and B2 phases. Other physical properties, including phase transition pressure, thermal expansion coefficient, isovolumic heat capacity, and entropy, are investigated. The limitations of the new potentials are discussed.

Ice friction at the nanoscale

The origin of ice slipperiness has been a matter of great controversy for more than a century, but an atomistic understanding of ice friction is still lacking. Here, we perform computer simulations of an atomically smooth substrate sliding on ice. In a large temperature range between 230 and 266 K, hydrophobic sliders exhibit a premelting layer similar to that found at the ice/air interface. On the contrary, hydrophilic sliders show larger premelting and a strong increase of the first adsorption layer. The nonequilibrium simulations show that premelting films of barely one-nanometer thickness are sufficient to provide a lubricating quasi-liquid layer with rheological properties similar to bulk undercooled water. Upon shearing, the films display a pattern consistent with lubricating Couette flow, but the boundary conditions at the wall vary strongly with the substrate's interactions. Hydrophobic walls exhibit large slip, while hydrophilic walls obey stick boundary conditions with small negative slip. By compressing ice above atmospheric pressure, the lubricating layer grows continuously, and the rheological properties approach bulk-like behavior. Below 260 K, the equilibrium premelting films decrease significantly. However, a very large slip persists on the hydrophobic walls, while the increased friction on hydrophilic walls is sufficient to melt ice and create a lubrication layer in a few nanoseconds. Our results show that the atomic-scale frictional behavior of ice is a combination of spontaneous premelting, pressure melting, and frictional heating.

Geochemistry of meta‐mafic and meta‐tonalite‐trondhjemite intrusives from Jaintia and Karbi Anglong hills of Shillong Plateau, North East India: Implications on the evolution of the Proterozoic Shillong Basin

We present the whole‐rock and mineral chemical data of the Khasi meta‐mafic/basic‐trondhjemite intrusives (KMI) and meta‐tonalite‐trondhjemite (MTT) that coevally emplaced the Proterozoic Shillong Group (SG) of Shillong Plateau, northeast (NE) India and discuss their petrogenetic‐tectonic origin. The calc‐alkaline to tholeiite KMI are compositionally transitional between hornblende‐gabbro; hornblende‐diorite and minor‐hornblendite. They show Ta–Nb troughs and strong decoupling large‐ion lithophile/high field strength elements (HFSE) signature consistent with subduction zone‐related basic magmas. The calcic to calc‐alkaline, low‐Al2O3, and I‐type metaluminous Fe‐hedenbergite‐trondhjemite (KMT) exhibits similar trace and rare earth elements (REE) distribution to the KMI. The MTT on the other hand are depleted in trace elements and REE, and correspond with the I‐type granitoids, and are comparable to Proterozoic to Phanerozoic tonalite‐trondhjemite‐granodiorites. Gentle negative sloping of REE in KMI ([La/Lu]CN = 4.04 to 6.35) with moderate LREE, suggests partial melting or, fractional crystallization from a transitional source between garnet and spinel lherzolite. Although almost a flat pattern ([La/Lu]CN = 3.70 to 4.05) for MTT entails a high degree of partial melting from sources similar to Archaean Mafic Composite or Archaean Tholeiite. Trace elemental modellings ([Sr/Y] vs. Y and [La/Yb]N vs. YbN) for MTT infer low pressure (<15 kbar) and high degree partial melting of >50% in equilibrium with 10% garnet +90% amphibole residue. A relatively flat REE pattern with some elevated HREE of MTT compared to KMI suggests for depleted source. Bimodal plutonism and the prevalence of meta‐dacite‐rhyolite in SG invokes for tonalite‐trondhjemite‐dacite setting of a continental arc or, active continental margin tectonic setting. Emplacement of KMI initiated in a temporary relax‐extensional phase and MTT in a compressional regime. This is possibly caused by an over‐thickened crust later subjected to orogenic collapse, exhumation‐metamorphism, and decompressional melting. This event might have taken place between 1.0 to 0.5 Ga during the Pan‐African Orogenic crustal growth, linked to the amalgamation of Gondwana.

Importance of thickness reduction and squeeze-out Std-OIT loss for HDPE geomembrane fusion seams

The difference in seam squeeze-out antioxidant loss (in terms of standard oxidative induction time, Std-OIT loss) and thickness reduction are evaluated for three different 1.5 mm-thick high density polyethylene (HDPE) geomembranes (GMBs) seamed using a variety of welding parameters and two different wedge welders. Partial squeeze-out antioxidant loss was detected in seams created from each of the three materials examined, with the majority off loss occurring when seam thickness reductions fell between 0.4 mm and 0.8 mm. Seams with thickness reduction exceeding 0.8 mm were found to exhibit greater squeeze-out Std-OIT loss, with near full Std-OIT depletion for one material. Wedge welder size was found to influence this relationship, some seams created with the large wedge welder exhibiting a near full Std-OIT depletion from squeeze-out at approximately 0.6 mm thickness reduction. Variation in seaming pressure and high load melt index (HLMI) were found to shift the degree of thickness reduction a seam may experience for a given welding speed and temperature, with higher seaming pressure and HLMI values generally resulting in greater thickness reduction. Although, for a given welding speed, wedge temperature, and sheet temperature combination, changes in seaming pressure had a limited effect on squeeze-out Std-OIT loss. This paper provides a rational basis into defining a practical 1.5 mm fusion seam thickness reduction criteria based on limiting antioxidant loss within a seam's squeeze-out and also provides a framework for identifying potentially higher risk fusion seams for future research.

The extrusion process of poly-cereal mixtures: study and calculation of the main parameters

Theoretical prerequisites for the extrusion of bulk components for the production of high-readiness products have been developed, which formed the basis for calculating and optimizing the main technological parameters of the extrusion process. It has been experimentally confirmed: firstly, the design parameters of the extruder and the initial humidity of the poly-cereal mixture have the greatest influence on the melt pressure of the product; secondly, the geometric characteristics of the working body, the frequency (speed) of the screw rotation and the pressure of the product maximally affect the temperature in the pre-matrix zone of the extruder. It was found that an increase in the rotation speed of the working organ (screw) from 80 to 250 min-1 leads to the highest value of the optimization criterion – the energy value of a poly-cereal food product of a high degree of readiness, respectively, for the poly-cereal mixture Fitness – 332.34 kcal and the poly-cereal mixture Health – 334.09 kcal.

(Digital Presentation) Preparation of Metal Halide Perovskite Thin Films Via Laser Deposition

We have been preparing metal halide perovskite (hereinafter referred to as perovskite) thin films by laser deposition. In this study, we report the results of our investigation of the effects of laser wavelength and fluence on the deposition process. One of the most important features of perovskites, which have been rapidly developed in recent years as materials for high-efficiency and low-cost thin-film solar cells, is the applicability of a simple process using solution coating under atmospheric pressure [1]. Crystal growth of perovskite by the solution method occurs through equilibrium chemical reactions, enabling the formation of thin films on the order of μm thickness in less than a few seconds; however, it is difficult to systematically control the crystal growth process at the molecular layer level by the solution method. On the other hand, in the physical vapor deposition (PVD) method, although the deposition rate is relatively low, ranging from sub-nanometer to several nm/s, the deposition can be controlled at the molecular layer level, as well as allowing different atoms to be readily introduced into the film. Therefore, the PVD method allows the addition of elements that are difficult to achieve with solution reactions and is suitable for studies that investigate the effects of such elements on physical properties.In laser deposition (LD), one of the PVD methods, materials are irradiated with an infrared (IR) or an ultraviolet (UV) laser beam, and thin films are formed by evaporation through IR heating or ablation with plasma formation through UV electron excitation. The advantage of LD is that it can cause instantaneous heating or ablation by switching on and off laser irradiation only on the material surface, thus enabling the deposition of molecular layers of organic materials with high vapor pressure or high melting point materials such as inorganic oxides with minimal cross-contamination caused by evaporation. We have prepared perovskite thin films by alternate deposition of PbI2 and CH3NH3I (MAI) using an IR laser and solid-phase reaction at room temperature aiming at the detailed investigation of the crystal growth process and introduction of various dopants in perovskite materials. [2, 3]. In this study, we have also performed perovskite film deposition by UV pulsed laser and investigated the difference in the physical properties of the perovskite films compared to those deposited by IR laser.Fig. 1 shows a schematic structure and appearance of the laser deposition system used in this experiment. The experimental method is described below. A synthetic quartz substrate was introduced into an ultra-high vacuum chamber with a base vacuum of 2×10-5 Pa., Then a semiconductor continuous IR laser (wavelength: 808 nm) or a UV pulse laser beam generated by the fourth harmonic of an Nd:YAG Q-Switch laser (wavelength: 266 nm, 10 Hz) was irradiated alternately onto PbI2 and MAI targets to form CH3NH3PbI3.The optical band gap of the thin films deposited by continuous infrared laser deposition shows a change in optical band gap depending on the thickness of the alternately deposited PbI2 and MAI, which can be attributed to the different content ratios of the tetragonal and orthorhombic phases. Interestingly, in UV pulsed laser deposition, the deposition rate was about 0.35 nm/s under the high laser fluence condition with lens focusing, while a high deposition rate of 20 nm/s was obtained under the low laser fluence condition without lens focusing. This result suggests that the excess kinetic energy of the deposition precursor in the case of lens-focused deposition causes re-sputtering on the surface of the already deposited film, resulting in a reduction of the effective deposition rate.In the presentation, we will demonstrate and discuss the results of crystallinity and optical absorption properties.[1] T. Miyasaka, A. Kulkarni, G. M. Kim, S. Öz and A. K. Jena, Adv. Energy Mater. 2020, 11902500 (2020).[2] K. Kawashima, Y. Okamoto, O. Annayev, N. Toyokura, R. Takahashi, M. Lippmaa, K. Itaka, Y. Suzuki, N. Matsuki and H. Koinuma, Science and Technology of Advanced Materials 18, 307 (2017).[3] N. Matsuki, Y. Iida, T. Shimada, Yuta Abeand T. Sato, ECS Meeting abst. MA2020-02, 1860 (2020). Figure 1

Tin (Sn) at high pressure: Review, X-ray diffraction, DFT calculations, and Gibbs energy modeling

An assessment of the Sn unary system is presented. First, the literature on phase equilibria, the thermodynamic properties, the volume and related properties, and shock compression of tin is thoroughly reviewed. Second, the Sn system is investigated by means of synchrotron X-ray diffraction in a diamond-anvil cell up to pressures and temperatures of 57 GPa and 730 K. New information is obtained on the thermal stability and thermal expansion coefficient of the {\gamma} (I4/mmm) and {\gamma}" (Im-3 m) phases. Third, density functional theory calculations are conducted on the six allotropic phases of tin observed in experiments using both a local density approximation (LDA) and a generalized gradient approximation (GGA) functional. This combined experimental and theoretical investigation provides further insights on the pronounced metastable nature of Sn in the 30 - 70 GPa range. Last, a Gibbs energy modeling is conducted using the recently proposed Joubert-Lu-Grover model which is compatible with the CALPHAD method. Special emphasis is placed on discussing extrapolations to high pressures and temperatures of the volume and of the thermodynamic properties. While the description of the heat capacity is approximate at moderate pressure, all available data are closely reproduced up to 2500 K, which is 5 times higher than the atmospheric pressure melting point of tin, and 150 GPa, which is almost 3 times the standard bulk modulus of \b{eta}-Sn.