Binary Phase Research Articles

PERFORMANCE IMPROVEMENT OF CIRCULAR PARABOLIC CONCENTRATING SOLAR COOKER USING NANO-MIXED BINARY SALT PHASE CHANGE MATERIAL

A multi-objective investigation has been carried out for a parabolic concentrator-type solar cooker with the use of nano-mixed binary salts phase change material (PCM) materials. Binary salts like NaNO<sub>3</sub> and KNO<sub>3</sub> are mixed with alumina (Al<sub>2</sub>O<sub>3</sub>) nanoparticles in the ratio of 0.5%, 1%, and 1.5% by weight. Properties such as thermal conductivity, specific heat, melting point, and thermal diffusivity are computed experimentally. Two food items, namely rice and dal, are selected for cooking purposes. The experimental results obtained from this research work show some promising returns. As compared to the plain PCM, the nano-mixed PCM reduces the cooking time, and with an increase in the addition of nanoparticles in PCM, the overall cooking time for both food items decreases. A difference of 5-6 minutes has been observed between plain PCM and nano-mixed PCM cooking. Another important observation made during this study is that the thermal properties of PCM material are affected by the addition of nanoparticles. The thermal conductivity increases by almost 10% and thermal diffusivity increases by 20%. The melting point of PCM decreases by 22°C, and the specific heat decreases by 12% and 17% at a temperature of 100°C and 250°C, respectively. Finally, it is concluded that the use of alumina nanoparticles in the binary salts PCM improves the thermal storage capacity of the PCM material.

Experimental investigation on nucleating agent for low temperature binary eutectic salt hydrate phase change material

The melting enthalpy and melting temperature have a significant impact on the latent heat that results from phase change materials (PCMs) used for thermal energy storage. Among the PCMs that are currently on the market, inorganic salt hydrates have greater thermal conductivity and latent heat than organic PCMs. However, the problem of salt hydrates' degree of supercooling limits their use in energy storage devices. Using sodium carbonate decahydrate (SCD) and sodium phosphate dibasic dodecahydrate (SPDD), a low temperature inorganic-inorganic eutectic salt hydrate PCM with a higher melting enthalpy and intended phase transition temperature is developed in this research study. The eutectic SCD/SPDD salt hydrate PCM eutectic point and the eutectic composition of salt hydrate PCMs to operate at low temperature range is numerically determined using Schrader equation. By numerical methods we obtain the 68 wt% of SCD with 32 wt% of SPDD to exhibit eutectic SCD/SPDD composite with eutectic melting temperature of 26.2 °C and melting enthalpy of 210.6 J/g. The synthesised eutectic PCM are characterised to explore their chemical stability, latent heat, melting point and their shortcoming due to degree of supercooling. A good way to get around the problem of the supercooling degree is to disperse the nucleating agents. In order to assess the type and degree of supercooling, the produced eutectic PCM composition is experimentally evaluated at 1–10% utilising borax, alumina, and sodium sulphate dodecahydrate as nucleating agents. However, for building cooling applications PCM with minimal degree of supercooling, with the ability to release low enthalpy during discharging is an advantage.

THERMODYNAMIC STUDY OF THE CdSb COMPOUND BY THE ELECTROMOTIVE FORCE MEASUREMENTS METHOD

Thermodynamic properties of CdSb binary compound were determined using an electromotive force measurement (e.m.f.) method with a liquid electrolyte in the ~300-450K temperatures interval. Equilibrium alloys from the CdSb+Sb phase region of the Cd-Sb system was analyzed by means of the e.m.f. measurements. Phase compositions of all samples were controlled using powder X-rays diffraction method. The partial molar functions of cadmium in alloys, the standard thermodynamic functions of formation, as well as the standard entropy of the CdSb compound were calculated. A comparative analysis of obtained results with literature data was performed.

Signature of low-dimensional quasi-F centers in zirconium-rich electrides.

Electrides are a class of materials consisting of non-nuclear excess electrons as quasi-F centers or Farbe centers within a positively charged lattice framework, and have significant applications in the fields of electrochemistry, spintronics, and electrode materials. Using first-principles quantum mechanical calculations, we have demonstrated exotic electronic structures of zirconium-rich electrides, Zr2X (X = O, Se, and Te), and obtained the quantitative values of charge transfer (oxidation states), and projected density of states associated with the localized quasi F-centers. The localized interstitial anionic electrons exhibit significant charge transfer values of approximately -1.88, -2.01, and -1.79 per atom in Zr2O, Zr2Se, and Zr2Te, respectively, and contribute actively in the electronic band structures and density of states at the Fermi level. From the 2D contour plot of the electron localization function (ELF), it has been predicted that the spatial distribution of the quasi-F centers stabilizes in the form of a one-dimensional pattern, with localized ELF sites interconnected with delocalized electron channels. Further, low work-function values of Zr2X, ranging from 2.7-3.4 eV, confirm the electride properties of these binary compounds, promising applications in electro-catalytic oxidations and anode materials in batteries. These unique electronic properties of anionic electrons free from nuclear binding in Zr2X have not been reported yet in the literature.

Synthesis of CuSe/PVP/GO and CuSe/MWCNTs for their applications as nonenzymatic electrochemical glucose biosensors.

Copper selenide (CuSe) is an inorganic binary compound which exhibits metallic behavior with zero band gap. CuSe has multiple applications in electrocatalysis, photothermal therapy, flexible electronic and solar cells. In the current study, copper selenide based nanocomposites CuSe/PVP/GO and CuSe/MWCNTs were synthesized by using the sol-gel method for application as a non-enzymatic glucose biosensor. Different characterization methods were employed, such as X-ray diffraction (XRD), photoluminescence (PL), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis) spectroscopy, and photoluminescence for determining various aspects of CuSe/PVP/GO and CuSe/MWCNTs nanocomposites including phase formation, functional group analysis, band gaps and morphology. Electrochemical impedance spectroscopy (EIS) showed that the resistances of modified electrode/bare electrode were 12.3 kΩ/17.3 kΩ and 6.3 kΩ/17.3 kΩ for CuSe/PVP/GO and CuSe/MWCNTs nanocomposites, respectively. Cyclic voltammetry showed that both CuSe/PVP/GO and CuSe/MWCNTs nanocomposites are promising biosensors for detection and monitoring of the glucose level in an analyte. The sensitivity and limit of detection are 2328 μA mM-1 cm-2/0.2 μM and 4157 μA mM-1 cm-2/0.3 μM for CuSe/PVP/GO and CuSe/MWCNTs, respectively. Chronoamperometry confirmed that our nanocomposite was the best sensor for glucose even in the presence of other interferents like ascorbic acid (AA), uric acid (UA) and dopamine (DA).

Nanocomposite of Nb-based binary phase for lowering the activation energy of Li+ intercalation as an anode for high-performance aqueous dual-ion batteries

A Nb-based binary-phase composite anode delivers a higher capacity in an aqueous dual-ion battery and suppresses water splitting to achieve a higher coulombic efficiency and long cycle life.

Binary Phase Shaping and SHG Contrast Ratios

Binary Phase Shaping and SHG Contrast Ratios

Designing Constant Modulus Approximate Binary Phase Waveforms for Multitarget Detection in MIMO Radar Using LSTM Networks

Designing Constant Modulus Approximate Binary Phase Waveforms for Multitarget Detection in MIMO Radar Using LSTM Networks

Resonant Radar Reflector On VHF / UHF Band Based on BPSK Modulation at LEO Orbit by MRC-100 Satellite

This paper presents a novel method for identify ing and tracking PocketQube satellites: the MRC-100 satellite is a model, and this method is based on a resonant radar reflec tor. The resonant reflector’s basic concept is that the resonant reflector uses a VHF/UHF communication subsystem antenna; there is no radiated RF signal, which means the power con sumption is only some Milliampere (mA). The continuous wave (CW) illuminator RF source is on the ground, and the onboard antenna receives the CW RF signal from the Earth. The micro controller (uC) periodically switches PIN diode forming BPSK modulated signal reflection so that another Earth station can receive the backscattered Binary Phase Shift Keying (BPSK) modulated signal. Also, it can detect the satellite if the ground station receiver can use a matched filter like a correlation re ceiver. If the ground station receiver knows the BPSK code of the satellite, it can detect it. If not, there is no way to detect the satellite. This method is similar to Radio Frequency Identifica tion (RFID) applications, but the reader is the ground station, and the tag is the satellite.

Mitigation of freeze-thaw damage to open-graded friction courses in seasonal climate areas via a binary phase change system

For the road performance deterioration of the open-graded friction courses (OGFCs) due to the scenarios of rainfall, snowfall, rapid temperature change, large temperature difference, and freeze-thaw cycle in seasonal climate areas, it will be necessary to utilize new techniques for improving the temperature regulation capability and freeze-thaw damage resistance of OGFC mixtures. A combined technique of mixing simultaneously two microencapsulated phase change materials (MPCMs) with different phase change temperature ranges and proportions has a special attractiveness for asphalt pavement. Successful application of a binary phase change system concept to improving asphalt pavement temperature regulation still has many problems, such as environmental conditions, coating MPCMs with Portland cement, mixing contents and proportions of different MPCMs, and factors affecting the temperature regulation capability and improving the freeze-thaw damage resistance of OGFCs. Composite MPCMs (CMPCMs) were prepared by two MPCMs of P46 and P5 coated by cement, in which P46 and P5 use paraffin and n-tetradecane respectively as the core material and SiO2 as the shell. The heating, cooling, freeze-thaw, and uniaxial compression tests on CMPCM-OGFC specimens were performed, to evaluate the temperature regulation capability of OGFC mixtures with different contents and proportions and the dependences of compressive strength, strength loss rate, and strain of OGFC mixtures on freeze-thaw cycle. The results reveal that the OGFC mixtures with different CP46 contents have a cooling effect due to the phase change heat absorption in a higher temperature range during the rising temperature and with different CP5 contents have a warming effect due to the phase change heat release in a lower temperature range during the cooling temperature. After mixing simultaneously CP46 and CP5 in different proportions, the temperature regulation capability of mixtures with a 3% content has a great improvement due to triggering respectively two types of phase change effects in a higher temperature range for CP46 and in a lower temperature range for CP5. Adopting this binary phase change system as mixing CP46 and CP5 can reduce the rising/cooling temperature rates in the freeze-thaw process and mitigate the damage of OGFC mixtures due to the high-temperature thawing and low-temperature frost heave effects.

Template-free synthesized porous ZnO-CdS spherical-shell S-scheme heterostructure assisted with Pt nanoparticle for enhanced photocatalytic H2-production

S-scheme heterojunctions present excellent photocatalytic performance for water splitting. Herein, an ideal distinctive heterostructure of porous ZnO-CdS/Pt spherical-shell was achieved by template-free method. It possesses the H2-generated efficiency of 32.15 mM·h−1·g−1, significantly surpassing the single or binary compounds. The remarkable photocatalytic activity stems from the unique morphology, S-scheme mechanism and the coordination of noble metal. Exceptional porous spherical-shell structure can localize the light, promote light scattering, increase adsorption capacity and bring abundant active sites. The reduction in transfer distance for carriers, inhibition of electron-hole recombination, as well as diminution of mobility resistance endues the heterojunction with efficient carrier separation and strong redox capacity. The probable mechanism was also estimated by the characterizations of XPS, UV, PL, PEC, EIS, M-S and ESR. This article provides a new method for spherical-shell structure fabricated without template, and proposes a significant promise for the construction and application of highly efficient photocatalysts for H2-production.

Fundamental changes in notions of the metallic alloy’s nature

The article "Fundamental changes in notions of the metallic alloys nature" is a collection of ideas and experimental results that unequivocally indicate that modern ideas about metallic alloys should become to history of alloys. Here we present to the reader the results of experiments obtained on two binary alloys Ni75Mo25 and Ni88Al12, as well as on one ternary alloy Ni53Mo35Al12. These data are identical to the data we presented earlier obtained on alloys of 17 binary systems and seven ternary alloys. Briefly, the main conclusions of the experiments are as follows: · Interatomic chemical interactions exist in all metal alloys at temperatures of both solid and liquid states. · Chemical bonds in alloys have an amazing property to change their sign at a certain temperature (there is a phase transition "ordering - separation"). · The reason for this transition is the electronic transition "ionic bond ↔ covalent bond". · The process of formation of new phases in alloys begins with the formation of diffusion micro-pairs formed during the melting of the alloy. Such considerable differences between the existing notions about the nature of alloys and those revealed in this work should lead to changes in the technology of heat treatment of alloys, in the binary phase diagrams and to a change in the principles of creating new alloys.

Analysis of the self-consistency of nucleation in the diffuse interface limit of binary alloy phase field models

This paper examines the process of nucleation in phase field (PF) models, with the aim of elucidating how the use of diffuse interfaces often employed for quantitative modelling of solidification affects nucleation rates and distribution statistics in relation to the predictions of classical nucleation theory. Nucleation is simulated through the use of noise in a quantitative binary alloy PF model using different interface widths. Our results reveal that the rate of nucleation in the PF model is found to be strongly dependent on the scale of the interface width and the numerical discretization, but that careful control of these quantities offers the possibility of a consistent interpretation of nucleation rate. The paper ends by assessing some of the practical merits of seeded versus noise-induced nucleation in PF modelling in the diffuse-interface limit, while also emphasizing how nucleation in this limit is fundamentally flawed from a quantitative perspective.

A SPIN-1 ISING MODEL INVESTIGATION OF THE MAGNETIC SYSTEM IS CARRIED OUT WITHIN THE CONTEXT OF GENERALIZED STATISTICAL MECHANICS

In this study magnetization has been investigated with the help of Ising model in the frame of non-extensive statistical mechanics where a behavior of interacting elementary moments ensemble is taken into consideration. To examine the physical systems with three states and two order parameters, researchers employ the spin-1 single lattice Ising model or three-state systems. Within this model, various thermodynamic characteristics of phenomena like ferromagnetism in binary alloys, liquid mixtures, liquid-crystal mixtures, freezing, magnetic order, phase transformations, semi-stable and unstable states, ordered and disordered transitions have been investigated for three distinct forms associated with q < 1, q = 1, and q > 1. In this context, q represents the non-extensivity parameter of Tsallis statistics.

A comprehensive first-principles insights into the physical properties of binary intermetallic Zr3Ir compound

We have looked into the structural, mechanical, optoelectronic, superconducting state and thermophysical aspects of intermetallic compound Zr3Ir using the density functional theory (DFT). Many of the physical properties, including detailed direction dependent mechanical properties, hardness in different formalisms, Fermi surface topology, machinability, fracture toughness, optical properties, chemical bonding nature, and charge density distributions, are being investigated for the first time. According to this study, Zr3Ir exhibits ductile features, high machinability, significant metallic bonding, a small Vickers hardness with low Debye temperature, and a modest level of elastic anisotropy. Ductility, high level of machinability, and damage tolerance make this compound attractive for engineering applications. The mechanical and dynamical stabilities of Zr3Ir have been confirmed. The metallic nature of Zr3Ir is seen in the electronic band structures with a high electronic energy density of states at the Fermi level. The bonding nature has been explored by the charge density mapping and bond population analysis. Zr3Ir shows a remarkable electronic stability, as confirmed by the presence of a pseudogap in the electronic energy density of states at the Fermi level which is situated between the bonding and antibonding states. Energy dependent optical parameters show very good agreement with the electronic density of states profile. The reflectivity spectra reveal that Zr3Ir is a good reflector in the infrared and near-visible regions. Zr3Ir is an excellent ultra-violet (UV) radiation absorber. High refractive index at visible photon energies indicates that Zr3Ir could be used to improve the visual aspects of electronic displays. All the optical constants exhibit a moderate degree of anisotropy. Zr3Ir has a moderate melting point, high damage tolerance, and very low minimum thermal conductivity. The thermomechanical characteristics of Zr3Ir reveal that it is a potential thermal barrier coating material. The superconducting state parameters of Zr3Ir are also explored.

Successive magnetic transitions and magnetocaloric effects in intermetallic compounds RE5Pt3 (RE = Dy, Ho)

The structure, low-temperature magnetic transition behaviors, and magnetocaloric properties of rare-earth-based binary compounds RE5Pt3 (RE = Dy, Ho) were studied. Both of the compounds crystallize in the Mn5Si3 hexagonal structure with a P63/mcm space group. With the decrease of temperature, the compounds undergo a phase transition from the paramagnetic (PM) state to the ferromagnetic (FM) state, followed by a spin reorientation. In the paramagnetic region, the reciprocal magnetic susceptibilities of RE5Pt3 obey the Curie-Weiss law. The effective paramagnetic magnetic moment values were determined to be 10.59 μB/Dy3+ and 10.40 μB/Ho3+, respectively, with the corresponding paramagnetic Curie temperatures of 30.0 K and 16.4 K. The maximum magnetic entropy changes (-ΔSM) of RE5Pt3 (RE = Dy, Ho) were calculated to be 8.2 J/kg K and 9.1 J/kg K for a field change of 0–5 T. In addition, it is confirmed that the successive magnetic phase transition enlarges the magnetic entropy change and the working temperature region by Lorentz bimodal fitting. Evidently, the RE5Pt3 (RE = Dy, Ho) compounds with reversible MC effect are expected to have effective applications in the low-temperature range.

Exceptional magnetic and magnetoelastic behavior of rare-earth non-centrosymmetric Sm7Pd3

Magnetic compounds possessing an intrinsic combination of near-zero magnetization with high magnetic anisotropy are highly desirable for spinronic applications and memory recording. A comprehensive study of Sm7Pd3 binary compound uncovered a unique combination of strong magnetoelastic behavior, very low net magnetization, and exceptionally high magnetic coercivity. The temperature-dependent X-ray synchrotron powder diffraction study indicates the abrupt changes in the compound's lattice parameters at the magnetic ordering temperature of TC=169 K, although the crystal structure remains non-centrosymmetric hexagonal Th7Fe3-type down to 6 K. Density functional theory calculations confirm high intrinsic magnetocrystalline anisotropy of Sm7Pd3, which explains the extremely large coercivity of the polycrystalline sample, up to Hcr = 130 kOe at 2 K. This discovery brings to life a novel class of highly anisotropic materials that are distinctly different from known spintronic materials, making them interesting future systems for magnetic memory research.

Influence of a binary phase ZnO–CuO on the structural and reflectance properties of poly-ε-caprolactone based nanocomposites

The binary phase metal oxide of ZnO and CuO (BPMO-ZC) nanopowders were synthesized by the chemical bath deposition. The BPMO-ZC nanopowders were distributed through the poly-ε-caprolactone (PCL) matrix by solution casting. The effect of the BPMO-ZC on the structure, thermal and reflectance properties of PCL was investigated. The X-ray diffraction (XRD) confirmed the combined hexagonal wurtzite and cubic forms of the respective ZnO and CuO nanomaterials as well as an orthorhombic form of the semi-crystalline PCL nanocomposite films. Morphology included aggregated particles with heterogeneous distribution. Differential scanning calorimetry (DSC) showed that the degree of crystallinity of nanocomposites films increased in the presence of the nanopowders. Nanocomposites displayed poor thermal stability compared to PCL, but improved residue. Reflectance measurement revealed that the absorption edges of PCL shifted to higher wavelength with the addition of ZnO–CuO.

Metallic B2Si monolayer as a flexible anode material for Li, Na and K-ion batteries: A first principles study

Silicon-based 2D materials have garnered significant attention as outstanding anodes of alkali metal ion batteries (MIBs); nevertheless, the poor electrical conductivity and mechanical property have severely hindered their practical application. In this work, we conducted a detailed first principles calculation to examine a newly-developed 2D silicon-boron binary compound (named B2Si) as the anode of MIBs. The B2Si anode harbors the intrinsic metallicity and exhibits low Li/Na/K diffusion barriers of 0.26, 0.14 and 0.09 eV, which makes a great contribution to the high rate performance. The storage capacities for Li/Na/K are predicted to be 1908.57, 583.48 and 431.97 mA h/g, respectively, superior to the commercial graphite anode. Moreover, the B2Si anode has good mechanical property and structural flexibility, which could avoid destroying its structure on the metal ion intercalation/deintercalation process. These fascinating features render the B2Si monolayer an exceptional anode of MIBs.

Atomic Layer Deposition of Multi-Component Films Using Precursor Co-Dosing

A growing number of ALD applications require the deposition of ternary or quarternary compounds. Examples include doped films (e.g. ZnO:Al), mixed oxides to tune dielectric properties (e.g. HfZrO), tunable bandgap materials for solar cells (e.g. ZnOS) or opto-electronic materials (e.g. InGaN), and high mobility oxide semiconductors (e.g. InGaZnO). A common method to deposit multicomponent films in ALD is the supercycle approach [1], where sub-cycles of different binary compounds are combined to deposit films where the resulting net composition is determined by the cycle ratio of the individual sub-cycles. A drawback of the supercycle method is that essentially multilayer stacks are deposited instead of true alloys and the film composition varies out-of-plane, potentially impacting film properties.An alternative method is to use precursor co-dosing, where two or more precursors are simultaneously dosed and co-adsorb during a half-reaction. The resulting film composition is then determined by the ratio of the partial pressures of the individual precursors during the precursor dose. As each ALD cycle deposits a true alloy, it results in excellent out-of-plane compositional uniformity. The co-dosing method has first been reported in the late 1980’s to deposit ternary and quarternary III-V compounds [2] and has been used since for a wide range of materials. In the last decade it has become the method of choice for depositing multicomponent materials with Spatial ALD.A proper understanding of the relation between film composition and precursor partial pressure during co-dosing is essential for accurate control of the film composition. This is not straightforward, as the surface chemistry of co-dosing can be quite complex, involving competitive adsorption, heterogeneity of reactive sites, exchange reactions and more. We will discuss how the surface chemistry of precursor co-dosing determines the film composition. In analogy to the IUPAC classification of adsorption isotherms for single adsorbents [3], we will introduce a similar classification of adsorption isotherms for multiple absorbing precursors which we will use to review and explain results reported in literature. Finally, we will discuss some interesting new opportunities for co-dosing, such as the deposition of gradient composition films and the use of co-dosing for area-selective deposition.[1]: A. Mackus et al, Chem. Mater. 31 (2019) 1142[2]: M. Tischler, S. Bedair, J. Cryst. Growth 77 (1986) 89[3]: M. Thommes et al, Pure & Appl. Chem. 87 (2015) 87