Analysis Of Thermal Properties Research Articles

High porosity composite structures produced from poly(lactic acid)/hydroxyapatite microspheres using novel Dual Beam Laser Sintering method: Analysis of structural, mechanical and thermal properties

The paper discusses the applicability of the novel Dual Beam Laser Sintering (DBLS) method for processing of poly(lactic acid)/hydroxyapatite (PLA/HAp) composite powders. The composite microspheres were prepared using the solid-in-oil-in-water (S/O/W) emulsification technique. The three-dimensional structures made of composite microspheres with different filler content – 5 % and 10 % by weight of HAp were processed using DLBS that uses a new method of preheating the powder bed. The obtained results were compared to the case of pure PLA presented in our previous work.The quality of the powders was determined using Dry Laser Diffraction (DLS), X-Ray Computed Tomography (XCT), Revolution Powder Analysis (RPA) and Differential Scanning Calorimetry (DSC). The melt flow rate and the thermal conductivity of the microspheres were also determined. Conducted research shows that the morphology of the particle depends heavily on the HAp content which ultimately influences the powder flowability properties. Moreover, the properties of samples manufactured using DBLS were evaluated. The internal microstructure was reconstructed using XCT and the open porosity structures were revealed. The influence of both the porosity and the HAp reinforcement on the mechanical properties was observed. Additionally, a thermal DSC analysis was carried out, which allowed to assess how the filler and process parameters affect the degree of crystallinity of the obtained structures and the thermal degradation of the composite.In general, the presented study shows the possibility of designing part properties not only by means of the DBLS process parameters but also by influencing the powder material properties. Both raw material properties and process parameters affect the morphology of pores and therefore the mechanical properties of PBF processed material.

Analysis of mechanical and thermal properties of polypropylene composite reinforced with Luffa cylindrica

Vegetable fibers have an economic potential to be employed as polymer reinforcement. This is due to their low cost, biodegradability, recyclability, adequate mechanical properties, and because they come from renewable sources. The growing need for alternative materials that meet the demands of various industrial segments (aerospace, mechanics, automobile, petrochemistry, shipping, civil engineering etc) requires detailed investigations on their physical, mechanical, and chemical properties. Detailed information about the behavior of fibers in a polymer matrix can indicate whether they can produce a structural composite. This work investigated the mechanical and thermal properties of polypropylene (PP) samples containing 0%, 10%, and 20% (w/w) Luffa cylindrica fibers, as well as to analyze the morphology of the fibers before and after their processing with the polymer. The mechanical results of the composites showed that those plant fibers reduced the strain of pure PP, increasing its stiffness. Thermogravimetric trials revealed that the composite had its thermal stability reduced with an increase in fiber content.

Interfacial Properties and Melt Processability of Cellulose Acetate Propionate Composites by Melt Blending of Biofillers.

A series of eco-friendly biocomposites with improved mechanical properties and interfacial interaction were prepared by melt-mixing natural fibers using a cellulose acetate derivative as a polymer matrix and used to evaluate their mechanical, thermal, and morphological properties. The natural fiber used as a biofiller was pre-surface-treated by a refining process using alkali and natural enzymes to improve compatibility and increase interfacial bonding with biopolymer substrate. To increase the processability of the cellulose material, the raw material was plasticized and the composition prepared in the form of pellets in a twin-screw extruder by mixing with an additive before being molded through an injection process. For each composition, the interfacial bonding force between different materials was confirmed through morphology analysis and evaluation of mechanical and thermal properties. When biofillers and a viscosity modifier were used at the same time, the fabricated biocomposites had controllable crystallinity, stiffness, and elasticity and showed improved mechanical strength, such as tensile strength and flexural strength. These results indicated that interfacial properties could be increased through interfacial interactions between two different components due to appropriate surface treatment. In addition, it was confirmed that a composition having interfacial interaction, not a simple mixture, could be prepared by lowering both glass transition and melting temperature. The lowering of glass transition temperature increased the elasticity of the biocomposites, which have the potential advantage of easier melt processing when applied to various injection parts.

MODERN MATERIALS AND STRUCTURES USED IN HOUSING CONSTRUCTION: INTERNATIONAL EXPERIENCE

Introduction: The article addresses the possibility of using universal energy-efficient engineering and technological solutions in mass housing construction, regardless of the climatic region of construction, with account for modern development in Saint Petersburg (Russian Federation) and Münster (Germany). The article not only considers improvements in building technologies used in modern housing construction but also offers an overview of the latest energy-efficient materials and structures. Purpose of the study: We aimed to introduce energy-efficient solutions in housing construction using innovative technologies and materials. In addition to theoretical materials, practical calculations will be presented, clearly showing the advantages and disadvantages of various engineering and technical solutions. Methods: In the course of the study, we used a) a comparative analysis of physical and thermal properties as well as strength characteristics of building materials used in mass housing construction; b) a problem-logical method to analyze possible typical space-planning and structural solutions for the design and construction of buildings, with account for climatic conditions and geographical features of the construction region, in compliance with the basic principles of modern sustainable construction, energy and environmental standards, economic efficiency of the solutions used, in accordance with international European LEED and BREEAM and Russian GREEN ZOOM standards. Results: We propose to introduce, along with the already well-known and time-tested ones, innovative patented solutions in materials and construction technologies both in private and mass housing construction in the countries under consideration: Russian Federation and Germany. Discussion: The discussion of field tests and implementation of the latest building materials in housing construction clearly demonstrates the importance of international cooperation in this field at various levels. As a consequence of the growing volume of housing construction and energy consumption, there emerge new stricter requirements and standards for the quality of materials produced and their technical characteristics, as well as a variety of decorative solutions enabling the construction market to be competitive and meet the over-demand requirements of the rapidly developing industrial society, while necessarily taking environmental protection measures, including those on conservation and mindful use of natural resources.

Comparative thermal behavior, Rock-Eval signature and kinetics of distinct thermally mature vitrain, fusain lithotypes and coals from India

ABSTRACT Thermal and chemical properties of coals, and the lithotypes they contain, provide useful insight to their combustion and reaction behaviors. Analysis of thermal properties, proximate parameters, Rock-Eval signatures, and petrographic characteristics of vitrain, fusain lithotypes, and bulk coal samples of distinct ranks from Raniganj (high volatile bituminous A rank, HvbA) and Jharia (medium volatile bituminous rank, Mvb) basins (India) reveal contrasting features. The HvbA bulk coal is identified as the most reactive. HvbA and Mvb vitrains display comparable reactivities despite their distinct thermal maturities. Mvb vitrain generates spiky pyrograms, due to melt formation and bubble bursting typical of coking vitrains. Mvb fusian is more prone to self-heating, being characterized by an exothermic thermogram peak due to its greater propensity to adsorb oxygen. In contrast, HvbA fusain, with higher VM and ash, displays least reactivity. These features mean that Mvb coals require higher temperatures for ignition and consume more energy than HvbA coals. Multi-heating-rate Rock-Eval S2 pyrograms show excellent Arrhenius equation simulation fits for the HvbA and Mvb bulk coals and lithotypes, enabling determination of activation energies (E) and pre-exponential factors (A). Distinctive E and A values of the HvbA bulk coal are a consequence of its high liptinite content.

Thermal Property Analysis of Precision Machinery and Its Thermal Error Compensation

The machining error caused by the thermal deformation of machines or tools accounts for half or even more in the total error, and the machining precision could be improved by stabilizing the heat balance of the process system. However, few of the existing studies have concerned about the thermal deformation law caused by the high-speed self-feed spindle system that could meet the performance requirements of high-speed cutting in precision machining, therefore, it’s of great necessity to study the thermal properties of precision machinery. For this reason, this paper took the precision machinery with a high-speed self-feed spindle system as the subject to study its thermal properties and thermal error compensation. At first, this paper introduced the composition of the precision machining control system and analyzed the thermal properties of the subject. Then, the heat source and heat exchange forms of the precision machinery were analyzed, the thermal intensity of the internal and external heat sources during the machining process was calculated, and the corresponding thermal boundary conditions were given. After that, this paper divided the heat sources of the subject during high-speed cutting into two types: internal heat source and external environment heat source, and carried out analysis. Moreover, this paper gave the structure of a thermal error and temperature synchronous measurement system for precision machinery, integrated the features of the thermal error data of two groups of high-speed cutting process, and built a thermal error compensation model based on the Bayesian network. At last, experimental results verified the effectiveness of the model.

Polyvinylidene fluoride‐natural graphite flexible composite films: Formation of graphite nanosheets, electroactive phase, analysis of electrical and thermal properties

AbstractSolution blending technique has been employed to synthesize polyvinylidene fluoride (PVDF)‐natural graphite composite films. The surface tension of the solvent has been observed to play an important role in the reduction of graphite particle size and their dispersion in the polymer matrix as N‐N‐dimethylacetamide (DMAc) employed PVDF‐x wt% natural graphite (x = 3, 5) films exhibit higher conductivity than that of N‐N‐dimethylformamide (DMF) employed films of same composition. The dispersion of probe sonicated graphite particles in PVDF matrix has been observed to be better when DMAc solvent is used in comparison to DMF employed composite as revealed by optical microscope images. The electrical percolation threshold in PVDF‐natural graphite composites is identified below 0.5 wt% natural graphite due to remarkable reduction in the particle size of graphite which improved the network formation between them. FESEM analysis confirms the formation of graphite nanosheets. The coexistence of non‐polar α and electroactive γ phases of PVDF in the composites is confirmed by FTIR, XRD, and DSC analyses. Maximum fraction of γ phase, as calculated from FTIR, is 88% in PVDF‐3 wt% natural graphite composite. Thermal annealing of PVDF‐3 wt% natural graphite at 120°C for 5 h results in enhanced electroactive γ phase in the nanocomposite. The onset degradation temperature of PVDF is increased by 4°C in PVDF‐5 wt% natural graphite suggesting enhanced thermal stability of the composite. Room temperature I–V characteristics of PVDF‐x wt% natural graphite (x = 5, 7) composite supports space charge limited conduction to be the dominant mechanism of charge transport.

Effect of passive thermal management system on the electro-thermal performance of battery module

Passive thermal management systems (BTMS) based on phase change material (PCM) have been proposed in many articles, but more attention has been paid to the temperature effect of BTMS, and the influence of BTMS on the electro-thermal performance of battery module has rarely been studied. Therefore, composite PCM composed of lauric acid, expand graphite (EG) and graphene (GR) with a mass ratio of 8:1.5:0.5 is prepared and used for temperature control of Li-ion battery. Then, a series of experiments are performed to research the performance of the thermal management module based on the cPCM, including thermal property analysis, discharge tests under standard and extreme conditions. In addition, the Gaussian process regression (GPR) model is trained and tested with internal resistance data measured over a wide temperature range, and then combined with an electro-thermal model to estimate the heat generation of batteries and further research the effect of the BTMS on discharge performance. The experimental results show that the maximum temperature (Tmax) of the batteries with cPCM is 47.41 °C, and the maximum temperature difference (ΔTmax) between the batteries is 1.46 °C in the 2C discharge process at 40 °C. The estimation results show that the heat generation of batteries with cPCM is higher than that of the batteries without cPCM under the same working conditions, and it is more sensitive to ambient temperature even without phase transition.

Biodegradable-Glass-Fiber Reinforced Hydrogel Composite with Enhanced Mechanical Performance and Cell Proliferation for Potential Cartilage Repair.

Polyvinyl alcohol (PVA) hydrogels are promising implants due to the similarity of their low-friction behavior to that of cartilage tissue, and also due to their non-cytotoxicity. However, their poor mechanical resistance and insufficient durability restricts their application in this area. With the development of biodegradable glass fibers (BGF), which show desirable mechanical performance and bioactivity for orthopedic engineering, we designed a novel PVA hydrogel composite reinforced with biodegradable glass fibers, intended for use in artificial cartilage repair with its excellent cytocompatibility and long-term mechanical stability. Using structure characterization and thermal properties analysis, we found hydrogen bonding occurred among PVA molecular networks as well as in the PVA–BGF interface, which explained the increase in crystallinity and glass transition temperature, and was the reason for the improved mechanical performance and better anti-fatigue behavior of the composites in comparison with PVA. The compressive strength and modulus for the PBGF-15 composite reached 3.05 and 3.97 MPa, respectively, equaling the mechanical properties of human articular cartilage. Moreover, the increase in BGF content was found to support the proliferation of chondrocytes in vitro, whilst the PVA hydrogel matrix was able to control the ion concentration by adjusting the ions released from the BGF. Therefore, this novel biodegradable-glass-fiber-reinforced hydrogel composite possesses excellent properties for cartilage repair with potential in medical application.

Investigation of glass forming ability, crystallization behavior, and soft magnetic properties of Fe–B–P–C–Cu alloy ribbons

The effect of Cu content on GFA, crystallization behavior, and soft magnetic properties in high P Fe84+xB6P6C3Cu1−x (x = 0, 0.2, 0.4, 0.6, and 1.0 at. %) alloy ribbons were systematically investigated to balance the relationship between glass forming ability (GFA), heat treatment window, and soft magnetic properties of high saturation magnetic flux density (Bs) Fe-based nanocrystalline alloys. It was discovered that lowering Cu promotes the formation of an amorphous structure. The GFA of alloys rises from 23 μm for Fe84B6P6C3Cu1 to 29 μm for Fe84.4B6P6C3Cu0.6. Analysis of thermal physical properties shows that when Cu content is between 1.0 at. % and 0.6 at. %, reducing Cu in the alloys does not affect the onset temperature of the first crystallization peak (Tx1), the second one (Tx2), and ΔT (ΔT = Tx2 − Tx1), whereas when Cu content is less than 0.6 at. %, reducing Cu leads to an increase in Tx1 and a decrease in Tx2 and ΔT, which is not conducive to obtaining a wide temperature range of precipitation of a single α-Fe phase. The alloys have a wide range of crystallization annealing temperature (693–753 K) and annealing time (60–6 min) to obtain a low coercivity (Hc) of about 8.0 A/m, high Bs of about 1.80 T, and high effective magnetic permeability (μe) of about 10000 when Cu is between 1.0 at. % and 0.6 at. %. The Bs, Hc, and μe of Fe84.4B6P6C3Cu0.6 alloy annealed at 723 K for 30 min are 1.82 T, 8.1 A/m, and 10820, respectively.

Obtaining a freeze-dried biomaterial for skin regeneration: Reinforcement of the microstructure through the use of crosslinkers and in vivo application

Scaffolds are one of the emerging alternatives to the traditional techniques of tissue and organ repair and regeneration. They offer the necessary support to the healthy formation of new tissues. Highly porous and interconnected scaffolds for skin regeneration were manufactured and studied with two types of crosslinking, genipin and glutaraldehyde. Two accessible biopolymers, chitosan and gelatin, were used together as matrix and were incorporated with snail mucus and aloe vera like additives. The microstructure and thermal properties analysis determined that the best crosslinker was glutaraldehyde, presenting a more homogeneous range of pore sizes, uniform distribution of the porous structure and higher denaturation temperatures showing a greater degree of crosslinking and stabilization. Thus, in vivo studies were conducted with the implantation of these scaffolds in mice after causing a burn wound. The addition of Aloe vera in the scaffolds is highlighted, apparently the large number of glycoproteins present in Aloe vera were able to integrate well into the scaffolds. Their diffusion towards the damaged tissue allowed accelerated healing and injury reduction. The material made with aloe vera crosslinked with glutaraldehyde showed promising results in accelerating the healing process in vivo studies, suggesting a great skin substitute for wound healing applications.

An Analysis of the Thermal Behavior and Effects of Circular Quartz Crystal Resonators for Microbalance Applications.

The accurate calculation of vibration frequency is essential in design of circular quartz crystal resonators which are the core elements of high-precision microbalances used for testing and measurement. Currently, the prediction of thermal effects on frequency through an analytical analysis is still in its developmental stage, mainly due to the complexity of solving the 3-D equations with the consideration of asymmetric structure of resonators and electrodes along with material anisotropy. By using a scalar differential equation for vibrations with the eigen-displacement of thickness mode, the eigen-frequency of a plano-convex AT-cut circular quartz crystal plate with asymmetric electrodes is determined. Furthermore, the temperature effect in the scalar differential equation is successfully obtained by incorporating the incremental thermal field theory into the 1-D analysis. The theoretical results agree well with the experimental data. The combination of the thermal field and the thickness model for circular quartz crystal resonators can realize a full analysis of thermal properties in vital applications such as high-sensitivity microbalance sensors.

Synthesis and characterization of green-functionalized graphene nanofluids as an enhanced working fluid in heat transfer applications

Energy crisis is one of the major concerns that requires significant attention around the world. An access to reliable, sustainable, and affordable energy will not be attractive if the safety of human and environmental is neglected. Hence, the advancement of energy harvesting method is expected not to be just efficient, but also clean, safe, and environmental-friendly. In this research work, synthesis, and characterization of a green-based functionalized graphene nanofluids is presented. Clove extract was prepared and functionalized on the graphene nanoplatelets (GNP) using apple cider vinegar, followed by dispersion in distilled water to produce clove with apple cider vinegar functionalized graphene (clove+ACV GNP) nanofluids at 0.1 wt.% concentration. Characterization of the clove+ACV GNP nanofluids was carried out using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) to examine the successfulness of the synthesis and functionalization, while the thermal conductivity was determined using KD2 Pro Thermal Properties Analyzer. The covalent bonds shown in the FTIR spectrum, and the morphological structure from the SEM images have indicated that the synthesis and functionalization of clove+ACV GNP have been successfully carried out. As for the thermal conductivity, 0.1 wt.% of clove+ACV GNP nanofluids have shown up to 24.4% enhancement when compared with distilled water, 3.9% enhancement when compared to clove-functionalized GNP at the same concentration, and up to 6.8% when compared with conventional GNP nanofluids. These findings have given a preliminary insight that this safe, non-toxic- clove+ACV functionalized graphene nanofluids is a promising alternative to the conventional, toxic- nanofluids as an enhanced and effective working fluid in heat transfer applications.

Thermal conductivity of marine sediments influenced by porosity and temperature in the South China Sea

A series of laboratory studies were conducted to explore the thermal properties of marine sediments from the South China Sea. The test specimens were obtained from depths of 733 m below sea level to 3248 m below sea level. The thermal conductivity of marine sediments from the South China Sea was developed using the KD2 Pro thermal properties analyser. The influence of transportation on the thermal conductivity of marine sediments was investigated through a series of tests onboard or in the laboratory for different site samples. The influence of temperature and porosity on the thermal conductivity of marine sediments was investigated through a series of tests using a modified oedometer. Fifteen models in the literature divided into four categories were used for calculating the thermal conductivity of marine sediments. The results indicate that the measurement results onboard were not much different from those in the laboratory for the samples from the northern part of the South China Sea. The thermal conductivity of marine sediments increased with increasing temperature and decreasing porosity. Five literature models used to calculate the thermal conductivity of the upper soil on land had relatively good predictive effects for marine sediments using a fitting parameter.

Comparative Analysis of Compression Molded Products of Recycled Waste Poly(Vinyl Chloride) and Virgin Poly(Vinyl Chloride) Fill Material

Waste poly(vinyl chloride) fill material from the cooling tower of a power plant was used for mechanical recycling. Mechanical recycling is the processing of plastic waste without changing the original chemical structure of the plastic. The waste rigid poly(vinyl chloride) fill material was cleaned, grinded and compression molded at optimized conditions of time, temperature and pressure using a compression molding machine. Virgin poly(vinyl chloride) was purchased and compression molded by the same compression molding machine. The compression molded sheets of waste poly(vinyl chloride) and virgin poly(vinyl chloride) were characterized by attenuated total reflection Fourier transform infrared analyses, tensile properties analyses, and thermal properties analyses. The results revealed that waste rigid poly(vinyl chloride) fill material is mechanically recyclable into new products such as pipes, profiles, furniture and other related products.

Physical modification of maize starch by gelatinizations and cold storage

The effects of gelatinization at three selected temperatures (DSC characteristic peaks temperature: TO, TP, and TC) and subsequent cold storage (CS) treatment on structural characteristics, pasting, and rheological properties of maize starch (MS) were investigated. The pasting, rheological properties of MS was changed with the increase of gelatinization temperature from TO to TC, but were not further significantly changed if the gelatinization temperature was higher than TC. Pasting and thermal properties analysis suggested that gelatinization at TC (TC treatment) significantly increased the gelatinization and pasting temperature of MS. Moreover, TC treatment decreased breakdown viscosity by 8.49 times and setback viscosity by 2.53 times. Dynamic rheological measurements revealed that the TC treatment caused the lower G' and G" of MS, and decreased the thickening coefficient by 55.17 %. These results indicated that TC treatment could enhance the thermal stability properties of MS, inhibiting the shear and short-term retrogradation, the shear-thinning behavior of MS. Interestingly, the CS treatment further inhibited the shear and short-term retrogradation and the shear-thinning behavior of MS. The leaked starch molecules aggregate to form a harder structure after gelatinization and starch molecules were further aggregated after CS treatment, these all were hypothesized to be responsible for these results.

Melting Temperature Depression and Phase Transitions of Nitrate-Based Molten Salts in Nanoconfinement.

Hybrids of nitrate-based molten salts (KNO3, NaNO3, and Solar Salt) and anodic aluminum oxide (AAO) with various pore sizes (between 25 and 380 nm) were designed for concentrated solar power (CSP) plants to achieve low melting point (<200 °C) and high thermal conductivity (>1 W m–1 K–1). AAO pore surfaces were passivated with octadecyl phosphonic acid (ODPA), and the results were compared with as-anodized AAO. The change in phase transition temperatures and melting temperatures of salts was investigated as a function of pore diameter. Melting temperatures decreased for all salts inside AAO with different pore sizes while the highest melting temperature decrease (ΔT = 173 ± 2 °C) was observed for KNO3 filled in AAO with a pore diameter of 380 nm. Another nanoconfinement effect was observed in the crystal phases of the salts. The ferroelectric phase of KNO3 (γ-phase) formed at room temperature for KNO3/AAO hybrids with pore size larger than 35 nm. Thermal conductivity values of molten salt (MS)/AAO hybrids were obtained by thermal property analysis (TPS) at room temperature and above melting temperatures of the salts. The highest increase in thermal conductivity was observed as 73% for KNO3/AAO-35 nm. For NaNO3/AAO-380 nm hybrids, the thermal conductivity coefficient was 1.224 ± 0.019 at room temperature. To determine the capacity and efficiency of MS/AAO hybrids during the heat transfer process, the energy storage density per unit volume (J m–3) was calculated. The highest energy storage capacity was calculated as 2390 MJ m–3 for KNO3/AAO with a pore diameter of 400 nm. This value is approximately five times higher than that of bulk salt.

Siloxane-based high solid acrylic latex by mini-emulsion polymerization for coatings with improved water resistance

Water resistance of a coating is an important parameter in its protective nature. Therefore, developing a viable coating formulation for improved water resistance has significant research interest. In this study, we prepared an acrylic latex composed of poly (methyl methacrylate-co-butyl acrylate-co-acrylic acid) having high solid content (54–57 %) by mini-emulsion polymerization. Herein, we synthesized a methacrylate-terminated tetrafunctional siloxane monomer (MTS) and used it at 0.5–4.0 wt% as a crosslinking comonomer in the acrylic emulsion formulation. The structural elucidation of MTS was performed by FT-IR, 1H &13C NMR and ESI-MS analysis. The copolymer latexes were characterized in terms of their solid content, particle size and viscosity. All the high solid latexes were stable for months without any coagulum. The analysis of microscopic, optical, thermal and mechanical properties of the air-dried cast films exhibited that the copolymers with MTS had rough surface morphology, high optical transparency (~98 % transmittance), and improved thermal properties and poor mechanical properties. In addition, the films showed improved water resistance as observed from the increased water contact angle from 43.0° (0 % MTS) to 64.2° (1 % MTS) and reduced water absorption from 50 % (0 % MTS) to 18.2 % (1 % MTS). This work focusing on the incorporation of siloxane moieties for improving the water resistance and many other properties of acrylic coatings will make an advancement to develop fluorine-free protective coatings.

Thermo-mechanical fedamo based calculations of hea (Fe-Ni-Cx (X=0.3-0.5) ternary alloys system using Calphad method

The given research shows the thermodynamic analysis and calculation of the basic thermal properties of the high entropy alloy Fe-Ni-Cx (x=0.3-0.5) of concentration. The system is investigated through Thermo-calc package with FEDAT databases and Calphad method. The evaluation of interactions is found maximum at 0.04070 J/m2 in the Fe-Ni-C ternary alloy system. The FCC_A1 phase is found the phase associated with highest molar volume in the Fe- Ni-Cx (x=0.3-0.5) ternary alloy system. The phase FCC_A1 is having austenite coordination with increasing density and apparent heat capacity. The temperature variation results the composite phases to be disappears with required level. The system is found highest apparent heat capacity 0.39269 j/mol. The density of phases becomes constant and it indicates the rare temperature withstanding phases. The fluctuations in the density of phases are changing with temperature as a result of phase’s nature and stability. The better magnetic properties are found for Basic centered cubic structure with highest interfacial energy. The alloy shows better magnet ic coordination and thermodynamic properties enhancement for further analysis.

Physical and Thermal Properties Analysis of Hematite for Thermal Heat Storage.

Energy sustainability represents an important research topic for aiding decreasing energy dependence and slowing down climate changes. In this context, solutions using thermal energy storage through rock start to emerge, due to its natural benefits, when compared to more polluting alternatives. To understand whether a rock material can be considered a good thermal energy storage material for such solutions, it is necessary to evaluate the physical, chemical and thermal properties of such materials. Therefore, it becomes essential to understand how heat propagates in the rock and how voids influence the thermal properties. To achieve these goals, hematite ore from Moncorvo, Northeastern Portugal was used, in particular, to study the effect of grain size on thermal properties for three different sized lots. Chemical and physical changes between heated and unheated lots were detected using X-ray diffraction and particle size, as well as X-ray fluorescence analysis. Regarding thermal properties, a hot wire method approach was used with seven thermocouples. Additionally, a thermal inversion model to simulate the heat exchanges was also proposed, allowing changing the properties of the constituents, to fit the theoretical and experimental temperature curve. Furthermore, the model reveals how heat propagates inside the reservoir filled with hematite ore.