Comprehensive Physical Properties Research Articles

Study on magnesia alumina spinel heat storage ceramics for solar thermal power generation

AbstractSolar thermal storage ceramic materials use photothermal power generation technology to store heat energy, which is an important way to use clean energy and reduce carbon emissions. In this paper, MgAl2O4 ceramics were prepared by pressureless sintering with fused magnesia and α‐Al2O3 as the primary raw materials and TiO2 as the additive. The phase composition, microstructure, physical properties, thermal shock resistance, and thermal physical properties of MgAl2O4 thermal storage ceramics were studied. The results show that the main crystalline phase of B4 is MgAl2O4 and the secondary crystalline phase is MgTi2O5. Ti4+ is dissolved into MgAl2O4 lattice, which distorts the lattice, reduces activation energy, and promotes sintering. The sample B4 (69.73 wt% α‐Al2O3, 30.27 wt% fused magnesia, and 7 wt% TiO2) sintered at 1510°C had the best comprehensive physical properties, and its bending strength and bulk density were 89.41 MPa and 3.27 g/cm3, respectively. After 30 thermal shock cycles, the bending strength of the sample B4 is slightly lost. The thermal stress generated during the expansion and contraction of the grain volume led to the decrease of the bending strength. From room temperature to 1000°C, the specific heat capacity of sample B4 is .44–1.25 J/(g·K). The heat capacity increases with the increase of temperature, and the heat storage density increases. The heat storage density is 1218.75 kJ/kg (1000°C). Heat capacity increases with temperature due to intensified lattice vibration at high temperatures. Therefore, magnesia alumina spinel ceramics show great potential in solar thermal energy storage.

Study of dielectric polarization and electrical transport in Bi1·2Sb0·8Te0·4Se2.6 nanofilms

Studying the dielectric response of topological insulators (TIs) can unveil their unique physical mechanisms such as charge transport and spin-orbit coupling effects. However, due to the manifestation of material's topological nature and band structure primarily in nanofilm, such thickness poses challenges for dielectric testing. To date, research on TI dielectric aspects remains relatively unexplored. Therefore, this paper successfully synthesizes nanofilm of quaternary topological insulator Bi1·2Sb0·8Te0·4Se2.6 (BSTS) using laser molecular beam epitaxy (LMBE) technique. Utilizing a wide-frequency dielectric spectrometer and a comprehensive physical properties measurement system (PPMS), we measured and thoroughly analyzed the dielectric polarization and charge transport characteristics of BSTS. We observed various polarization responses in the frequency range of 101–103 Hz, with the dipole orientation gradually failing to keep pace with the frequency increase in the range of 103–105 Hz, and the relaxation polarization unable to establish itself in the range of 105–107 Hz, with polarization primarily contributed by displacement polarization. Subsequently, we further analyzed the dependence of BSTS dielectric polarization response on temperature and film thickness, which will help reveal the influence of external factors on TI dielectric response, providing crucial insights for controlling TI materials' dielectric response. This not only deepens our understanding of the fundamental physical properties of this novel material but also offers important scientific basis and technological support for its applications in quantum computing, photonics, spintronics, and other fields.

Enhancing the physical properties of styrene-butadiene-styrene (SBS)-modified asphalt through polyetheramine-functionalized graphene oxide (PEA-GO) composites

To enhance the dispersion of graphene oxide (GO) in Styrene-butadiene-styrene (SBS) modified asphalt (SA) and the comprehensive physical properties of GO/SBS-modified asphalt (GSA), PEA-GO composites were prepared by grafting polyetheramine (PEA) onto GO for the preparation of PEA-GO/SBS-modified asphalt (PGSA). In this study, the chemical structure of PEA-GO was examined using fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The conventional properties of GSA and PGSA were analyzed. The effects of GO and PEA-GO on the high and low-temperature prevalent properties of SA were investigated by dynamic shear rheology (DSR) test and bending beam rheology (BBR) test. The adhesion properties of GSA and PGSA were investigated by surface free energy theory (SFE). The surface micro-morphology of GSA and PGSA and the dispersion state of GO in SA were analyzed using atomic force microscopy (AFM) and fluorescence microscopy (FM). The results showed that the characteristic absorption peaks of N-H, CH2-CH2, and C-N appeared in the FTIR diagram of PEA-GO. A new peak appeared in the XPS diagram: C-N. The high-temperature performance, low-temperature crack resistance, and adhesion of PGSA were superior to those of GSA. The size of the "bee structure" in PGSA is larger than in GSA, and PEA-GO demonstrates uniform dispersion in SA. This study serves as a reference for fine-tuning graphene oxide (GO) at the microscopic level to enhance the physical properties of GSA.

Study on Bulk-Surface Transport Separation and Dielectric Polarization of Topological Insulator Bi1.2Sb0.8Te0.4Se2.6.

This study successfully fabricated the quaternary topological insulator thin films of Bi1.2Sb0.8Te0.4Se2.6 (BSTS) with a thickness of 25 nm, improving the intrinsic defects in binary topological materials through doping methods and achieving the separation of transport characteristics between the bulk and surface of topological insulator materials by utilizing a comprehensive Physical Properties Measurement System (PPMS) and Terahertz Time-Domain Spectroscopy (THz-TDS) to extract electronic transport information for both bulk and surface states. Additionally, the dielectric polarization behavior of BSTS in the low-frequency (10-107 Hz) and high-frequency (0.5-2.0 THz) ranges was investigated. These research findings provide crucial experimental groundwork and theoretical guidance for the development of novel low-energy electronic devices, spintronic devices, and quantum computing technology based on topological insulators.

Study on the Physical and Rheological Characterisation of Low-Density Polyethylene (LDPE)/Recycled Crumb Rubber (RCR) on Asphalt Binders

Recycled crumb rubber (RCR) is considered a reliable asphalt modifier and a solution to the problem of scrap tyre recycling. RCR-modified asphalt (RCRMA) typically has good low-temperature performance and storage stability. However, the pre-treatment of crumb rubber (CR) impairs its physical properties, resulting in poor high-temperature performance, which limits the industrial application of RCRMA. In this study, low-density polyethylene (LDPE) composite RCR was used to modify asphalt, and LDPE/RCR-composite-modified asphalt (L-RCRMA) was produced to compensate for the deficiencies in the high-temperature performance of RCRMA. The comprehensive physical properties of L-RCRMA were elucidated using tests such as the conventional properties, rotational viscosity, and rheological tests. The results showed that the incorporation of LDPE improved the high-temperature stability and rutting resistance of the asphalt, but an excessive amount of LDPE impaired the low-temperature performance and storage stability of L-RCRMA. Therefore, it is necessary to control the amount of LDPE to balance the performance of the asphalt. On this basis, we recommend a dosage of 20% for RCR and 1.5% for LDPE.

Improving comprehensive properties of high-density polyethylene matrix composite by boron nitride/coconut shell carbon reinforcement

Simultaneously enhancing the thermal conductivity, insulation, and mechanical properties of high-density polyethylene (HDPE) composites is highly desired for electronic and electrical applications. In this research, HDPE/boron nitride (BN)/coconut shell charcoal (CSC) composites were prepared. Benefit from the synergistic effect between the multi-dimensional hybrid fillers, the prepared HDPE/BN/CSC composites exhibited enhanced comprehensive properties compared to the HDPE/BN composites and pure HDPE. In particular, as for HDPE/25BN/3CSC (25 wt% BN, 3 wt% CSC) nanocomposites compared to the pure HDPE, enhancements in in-plane thermal conductivity of 980.89%, normal thermal conductivity of 138%, and tensile strength of 18.91% were obtained, while higher volume resistivity and decomposition temperature were achieved. This work provides a simple but effective way for improving the thermal conductivity and comprehensive physical properties of HDPE composites.

Comprehensive Physical Properties and Exploration Potential of the Permian Igneous Rocks in the Southwestern Sichuan Basin

The Permian igneous rocks in the Sichuan Basin represent a major breakthrough, opening up a new prospect for oil and gas exploration, and igneous reservoirs have become a new field of oil and gas exploration. Gravity-magnetic-electric exploration is an effective means of identifying igneous rocks and helps in reducing the multiplicity of the prediction results. However, the lithology of igneous rocks is quite different, and the exploration theory and evaluation techniques need urgently to be improved. In order to deeply study the response characteristics of the gravity-magnetic-electric and physical properties of the Permian igneous rocks in the Sichuan Basin and their relationships with the reservoir parameters, physical property testing was carried out on outcrop samples of the Permian igneous rocks in southwestern Sichuan. The comprehensive physical properties of the samples with different lithologies, including basalt, tuff, and volcanic breccia, were analyzed and studied. Based on the geological characteristics of the igneous rocks, such as the mineral composition, microstructure, and reservoir properties, a multi-parameter intersection relationship model for the resistivity, polarizability, density, magnetic susceptibility, and their relationships with the reservoir parameters was established, and effective parameters favorable for igneous rock identification and reservoir evaluation were identified. The results of this study provide a physical basis and technical support for non-seismic exploration of igneous oil and gas reservoirs in the Sichuan Basin.

Study on Properties of Graphene Oxide Modified Recycled Cement-Based Composites

Based on the replacement of natural sand by recycled fine aggregate of construction waste, the comprehensive physical properties and hydration mechanism of graphene oxide (GO) modified recycled cement-based composites (RCBC) were studied. The RCBC was prepared by ultrasonic dispersion GO and vibration stirring. The results show that the flexural and compressive strength of the RCBC modified by 0.03%GO at 7d age increase by 16% and 21% respectively, the flexural strength and compressive strength of RCBC modified by 0.02% GO at 28d age increase by 13.7% and 13.6% respectively. Good weather resistance and the freeze-thaw performance at age, Cl- contents is less than 0.06%. The radioactive detection results of GO/RCBC is IRa = 0.08 and Ir = 0.15, which belongs to Class A building materials. The hydration mechanism of the prepared GO/RCBC was studied by XRD, TG-DTA, SEM, and other means. The results show that GO promotes the formation of ettringite (AFt), calcium silicate hydrate (C-S-H) and the transformation of AFt and calcium hydroxide (CH) crystal form, thus improving the comprehensive properties of RCBC.

Atomization Characteristics of Hydrogen Peroxide Solutions in Electrostatic Field.

Hydrogen peroxide (H2O2) can be considered as a sterilant or a green propellant. For a common use in industrial application, spray is an effective method to form fine H2O2 droplets. In this paper, electrostatic atomization based on the configuration of needle ring electrodes is proposed to produce H2O2 spray by minimizing its effective surface tension. The breakup performances of H2O2 ligaments can be improved by increasing the electric field intensity, reducing the nozzle size, and adjusting suitable volume flow rate. The smallest average diameter of breakup droplets for 35 wt. % concentration H2O2 solution reached 92.8 μm under optimum operation conditions. The H2O2 concentration significantly influenced the breakup performance owing to the concentration effect on comprehensive physical properties such as density, surface tension, viscosity, and permittivity. The average diameters of breakup droplets decreased with decreasing H2O2 concentration. At 8 wt. % concentration, the average breakup droplet diameter was reduced to 67.4 μm. Finally, electrostatic atomization mechanism of H2O2 solution was analyzed by calculating dimensionless parameters of Re, We, and Oh numbers with the combination of the operation conditions and physical properties for in-depth understanding the breakup behaviors. The calculation showed that the minimum average diameter of breakup droplets was obtained at 8 wt. % concentration at the investigated range of H2O2 concentration, which kept in agreement with the experimental results.

Synthesis of an amino-terminated waterborne polyurethane-based polymeric dye for high-performance dyeing of biomass-derived aldehyde-tanned chrome-free leather

An amino-terminated waterborne polyurethane-based polymeric dye (AWPUD) was synthesized for the high-performance dyeing of chrome-free leather tanned by biomass-derived aldehyde (BAT). Fourier transform infrared spectroscopy (FTIR) and 1H NMR spectra illustrated the successful synthesis of AWPUD via incorporating small-molecule dyes (SMDs) (C.I. Acid Red 14) and sodium 2,4-diaminobenzenesulfonate into the polyurethane skeleton. The amino group content of AWPUD was tested to be 1.34 wt% (based on dry weight), which included 0.65 wt% of terminal amino groups. The characteristic absorption peaks of AWPUD were observed at 538 nm and 573 nm, similar to those of SMDs. AWPUD-dyed crust leathers exhibited better dyeing performances than SMD-dyed crust leather in terms of comparable dye penetration degree, lower chroma of wastewater, and higher filler-dye uptake ratio. In addition, AWPUD-dyed crust leathers had higher dyeing uniformity, dry-wet rubbing resistance, and thermal stability. Meanwhile, AWPUD-dyed crust leathers had better comprehensive physical properties in terms of higher mechanical strengths, comparable softness, and smooth grain surface. These results suggest that AWPUD has the great potential to be used in the high-performance dyeing of BAT-tanned leather.

Ab-initio molecular dynamics study on thermal property of NaCl–CaCl2 molten salt for high-temperature heat transfer and storage

NaCl–CaCl2 molten salt is considered as a promising high-temperature heat transfer and storage fluid for advanced nuclear power plants and concentrating solar power plants in the field of renewable energy utilization. However, the comprehensive physical properties and their microscopic mechanisms for the molten NaCl–CaCl2 are failed to be measured accurately due to the extremely measuring condition. In this work, the ab-initio molecular dynamics simulation is used to investigate its microstructures and thermophysical properties for entire operating temperatures. It reveals that ion clusters are formed in terms of three for face-sharing, two for edge-sharing, and one for corner-sharing Cl− ions between the coordination shells of two neighboring cations. The coordination numbers of Na+-Cl- and Ca2+-Cl- ion pairs decrease from 5.88 to 6.46 at 783 K to 5.33 and 6.02 at 1173 K respectively. Meanwhile, the reliable and meaningful values of densities, ion self-diffusion coefficients, viscosities, and thermal conductivities were evaluated from 783 to 1173 K. It suggests that the distances and interactions between ions pairs determine thermodynamic properties directly. The ab-initio molecular dynamics simulation is proved to be an effective way to obtain the essential data for the designs of heat transfer and thermal energy storage systems in practical applications.

Dielectric screening enabled ultrastable luminescence in CsPbBr3 perovskite crystal encapsulated by ferroelectric Poly(vinylidene fluoride)

Metal halide perovskites nanocrystals (NCs) are emerging as competitive alternatives for semiconductor NCs in the fields of consumer optoelectronic devices; however, boosting their long-term stability still needs extensive study. Encapsulation of perovskite NCs with polymer becomes a promising strategy, yet the dielectric screening effect on the excitons of perovskites from the polymer matrix has seldom been considered. Here, we demonstrated this effect in high-permittivity poly(vinylidene fluoride) (PVDF) encapsulated CsPbBr3 (CPB) crystals CPB/PVDF composites films. The in situ nonuniform growth mechanism of CPB crystal with respect to its concentration in the precursor was revealed from multiscale structure observations. Comprehensive physical properties of CPB/PVDF composites with varying CPB concentrations were thoroughly investigated. Composite films made from precursors with CPB concentration increasing to saturation all showed bright luminescence, and an exceptional long fluorescence lifetime up to τavg = 731 ns was observed, much superior to other polymers with lower permittivity encapsulated CPB composites. The stable luminescence is understood from the strong interplay between electron-hole Coulomb interactions in CPB and its surrounding high-permittivity PVDF. Meanwhile, the interfacial interaction between CPB and PVDF greatly influenced the crystallization behavior of PVDF polymer at nanoscale, thus altered the dielectric and mechanical properties of CPB/PVDF composite films accordingly. Finally, a warm white light-emitting diode device was assembled based on green light emitting CPB/PVDF film, positively implying its potential application in high-performance optoelectronic devices.

Friction and Wear between Polymer and Metal in the Mixing Process.

In order to obtain a longer mixing chamber life, a layer of hard alloy coating is generally welded on the surface. However, when the mixing chamber is used for a long time, the surface will be worn due to friction with small fillers and rubber. As a result, there will be a large gap between the mixing chamber and the rotor, which will further affect the quality of the mixed rubber. In this paper, the dispersion process of the reinforcing system is simulated at first, and the mixed rubber samples are obtained from different dispersion stages in preparation for experiments with the chamber material. On this basis, the friction experiment is carried out with the same material as the mixing chamber on the friction experiment machine employed in the improved test part. The experiment shows that the friction and wear between the mixture and metal produced in each mixing stage are different. The wear in the stage with high friction is not necessarily large. The wear will be intensified in the middle and later mixing periods, while the friction will tend to be stable. In this paper, besides the exploration on the friction of fillers and rubber on the mixing chamber in different mixing stages, the most important thing is to change the mixing process of rubber formula, so as to extend the service life of the mixing chamber without changing the comprehensive physical properties of the mixing rubber.

Sulfide ore prospecting in carbon-containing stratum using comprehensive time-domain induced polarization and controlled-source audio-frequency magnetotellurics

Carbon-bearing stratum normally features low resistance and high polarization. If the lithostratigraphy of the exploration area contains large amounts of carbon, the induced polarization anomaly caused by metal sulfide ore bodies will be inundated by the high polarization of carbon-containing wall rock. In this work, we adopted time-domain induced polarization (TDIP) and controlled-source audio-frequency magnetotellurics (CSAMT) on deep prospecting of the carbon-bearing stratum of the Ar Horqin Banner, Inner Mongolia. The underground medium is divided into target geologic bodies according to the geological information within the known exploration line borehole, and the physical properties of various target geologic bodies are calculated using weighted averages to build a geologic-geophysical model that can fit the observation data. Consequently, we can determine the range and morphological characteristics of the electrical properties of the ore-bearing geologic bodies in the inversion results in the study area. Then we can use the characteristics summarized from the known exploration line to interpret unknown exploration line. Results indicated that, when the difference in physical properties between the ore body and interference wall rock is not clear, the geologic body can be classifi ed via the paragenetic (associated) assemblage relations of the underground medium. Geological interpretation is guided by the comprehensive physical properties of ore-bearing geologic bodies to avoid interferences.

Assessment on Physical and Rheological Properties of Aged SBS Modified Bitumen Containing Rejuvenating Systems of Isocyanate and Epoxy Substances

Styrene–butadiene copolymer (SBS)-modified bitumen (SMB) is widely applied in pavement construction. With yearly services, many SMB wastes urgently need to be reclaimed for repaving roads based on the objectives of environmental protection, landfill saving, as well as resource utilization. The present work is focused on the investigation of the physical and rheological properties of aged SMB incorporated with rejuvenating systems consisting of fluid catalytic cracking slurry (FCC slurry), C12–14 aliphatic glycidyl ether (AGE), diphenylmethane diisocyanate (MDI), and other additives. The rejuvenating systems containing the main components of 10% FCC slurry, 10%FCC/3%AGE, and 10%FCC/3%AGE/1% MDI were respectively recorded as Ra, Rb, and Rc. The results indicate that both Rb and Rc have obvious workability that make contributions for improving comprehensive physical properties while slightly reducing the softening point, which were also proven to be effective for the re-rejuvenation of re-aged binder. The higher viscous-elastic temperature caused by the agglomeration of binder molecules in aged SMB could be dropped to a lower value with rejuvenating systems, while improving the low-temperature crack resistance. With the use of the Rb and Rc rejuvenating systems, the high-temperature deformation resistance of aged SMB fell, approaching the performance of fresh SMB. Vibration noise consumption could be improved for aged SMB incorporated with Rb and Rc in the form of viscous loss, while the effects for re-aged SMB containing the same rejuvenating systems were weakened but still effective.

Novel instrument for characterizing comprehensive physical properties under multi-mechanical loads and multi-physical field coupling conditions.

Functional materials represented by ferromagnetics and ferroelectrics are widely used in advanced sensor and precision actuation due to their special characterization under coupling interactions of complex loads and external physical fields. However, the conventional devices for material characterization can only provide a limited type of loads and physical fields and cannot simulate the actual service conditions of materials. A multi-field coupling instrument for characterization has been designed and implemented to overcome this barrier and measure the comprehensive physical properties under complex service conditions. The testing forms include tension, compression, bending, torsion, and fatigue in mechanical loads, as well as different external physical fields, including electric, magnetic, and thermal fields. In order to offer a variety of information to reveal mechanical damage or deformation forms, a series of measurement methods at the microscale are integrated with the instrument including an indentation unit and in situ microimaging module. Finally, several coupling experiments which cover all the loading and measurement functions of the instrument have been implemented. The results illustrate the functions and characteristics of the instrument and then reveal the variety in mechanical and electromagnetic properties of the piezoelectric transducer ceramic, TbDyFe alloy, and carbon fiber reinforced polymer under coupling conditions.

Preparation and properties of polyimide/chopped carbon fiber composite foams

In this study, a series of reinforced polyimide (PI)/carbon fiber (CF) composite foams were fabricated through thermal foaming of polyester ammonium salt (PEAS) precursor powders. The PEAS precursor powders containing different contents of chopped CF were synthesized from benzophenone‐3,3′,4,4′‐tetracarboxylic dianhydride (BTDA) and 4,4′‐diaminodiphenyl ether (ODA). The effects of different CF loadings on foaming behavior of PEAS/CF composite precursor powders, final cellular morphology, and physical properties of PI composite foams were investigated. The results revealed that the chopped CF acted as nucleation agent in the foaming process. The dispersion of CF can be evaluated using digital microscope. It is interesting to find that the chopped CF were highly oriented along the direction of cell arrises. As a result, the mechanical properties of PI foams were significantly enhanced owing to the incorporation of chopped CF. Furthermore, the thermal stability of PI composite foams were also slightly improved owing to fine dispersion of CF. In addition, the PI/CF composite foam shows uniform cell size distribution and the best comprehensive physical properties as chopped CF loading at around 6 wt%. Copyright © 2016 John Wiley & Sons, Ltd.

Aerosols physical properties at Hada Al Sham, western Saudi Arabia

This is the first time to clearly derive the comprehensive physical properties of aerosols at a rural background area in Saudi Arabia. Aerosol measurements station was established at a rural background area in the Western Saudi Arabia to study the aerosol properties. This study gives overview of the aerosol physical properties (PM10, PM2.5, black carbon and total number concentration) over the measurement period from November 2012 to February 2015. The average PM10 and PM2.5 concentrations were 95 ± 78 μg m−3 (mean ± STD, at ambient conditions) and 33 ± 68 μg m−3 (at ambient conditions), respectively. As expected PM10 concentration was dominated by coarse mode particles (PM10–PM2.5), most probably desert dust. Especially from February to June the coarse mode concentrations were high because of dust storm season. Aerosol mass concentrations had clear diurnal cycle. Lower values were observed around noon. This behavior is caused by wind direction and speed, during night time very calm easterly winds are dominating whereas during daytime the stronger westerly winds are dominating (sea breeze). During the day time the boundary layer is evolving, causing enhanced mixing and dilution leading to lower concentration. PM10 and PM2.5 concentrations were comparable to values measured at close by city of Jeddah. Black carbon concentration was about 2% and 6% of PM10 and PM2.5 mass, respectively. Total number concentration was dominated by frequent new particle formation and particle growth events. The typical diurnal cycle in particle total number concentration was clearly different from PM10 and PM2.5.

Experimental research on the residual magnetization of a rare-earth permanent magnet for a cryogenic undulator

The magnetic properties of commercial polycrystalline Nd2Fe14B (N50M, N45H, N40SH, N35EH) and Sm2Co17 (XG30/20, XG26/25, XG22/20) magnets at cryogenic temperatures were tested by using a comprehensive physical properties measurement system (PPMS). The results show that the spin tilt temperature Tst of Nd2Fe14B magnets is closely related to intrinsic coercivity Hci, N50M and N45H with smaller Hci show a residual magnetization jump at 235 K and 225 K, respectively. For Sm2Co17 magnets, in 50–300 K, with temperature decreasing, residual magnetization Mrc shows a nearly linear increase, while in 10–50 K, Mrc has little change. The research results provide a reference for cryogenic undulators and other high-precision cryogenic devices.

Characteristics of the difference and change in the comprehensive physical properties of rocks

Based on the relationship between rock physical properties and atomic structures of chemical elements, this paper dissertates the characteristics between the difference and change in the comprehensive physical properties of rocks, such as density, elasticity, electrical property and radioactivity,etc. The examples in this paper show that the change of the comprehensive physical parameters of rocks reflects the change of atoms, molecules, minerals and their constitutions in rocks, and there are some correlations between these parameters.