Tc Values Research Articles

Long-time aging of La(Fe,Si,Mn)13Hz microparticles using different fluids for magnetic refrigeration systems

La(Fe,Si,Mn)13Hz alloys are promising solid-state refrigerant candidates for room-temperature magnetocaloric refrigeration due to their giant magnetocaloric effect, adjustable Curie temperature (TC) and low rare-earth content. For enhanced efficiency, the magnetocaloric material (MCM) is configured into an active magnetic regenerator (AMR), a porous, layered component with a chemically-tuned TC gradient. The porous structure facilitates heat exchange with a working fluid. It is crucial to preserve the thermomagnetic properties, such as TC and the magnetocaloric effect intensity, during refrigeration cycles. This study conducts a systematic investigation of the stability of three batches of La(Fe,Si,Mn)13Hz magnetocaloric microparticles, each with different values of TC. The commercially available microparticles (average size about 620 µm), which simulate AMR applications, underwent a 1-year immersion in deionized water and three water mixtures with corrosion inhibitors: Entek FNE (2 % vol.), ME-1 (5 %. vol.) and ME-3 (5 % vol.). Optical and scanning electron microscopy revealed surface changes within the first week of immersion in water and later in two fluids. The TC shifted towards higher temperatures (up to 13 K) after immersion, especially in water and in the ME-3-containing medium. After 40 weeks, the Entek FNE mixture caused some damage to the magnetocaloric materials. The lattice parameter of the La(Fe,Si,Mn)13Hz magnetocaloric phase changed, and magnetic entropy decreased for most aqueous media. Only ME-1 proved effective in preserving magnetocaloric microparticle properties for all TCs over a year, making it a potential candidate for long-term prototypes and commercial products.

Tongue color parameters in predicting the degree of coronary stenosis: a retrospective cohort study of 282 patients with coronary angiography.

This retrospective cohort study aimed to analyze the relationship between tongue color and coronary artery stenosis severity in 282 patients after underwent coronary angiography. A retrospective cohort study was conducted to collect data from patients who underwent coronary angiography in the Department of Cardiology, Shanghai Jiading District Central Hospital from October 1, 2023 to January 15, 2024. All patients were divided into four various stenosis groups. The tongue images of each patient was normalized captured, tongue body (TC_) and tongue coating (CC_) data were converted into RGB and HSV model parameters using SMX System 2.0. Four supervised machine learning classifiers were used to establish a coronary artery stenosis grading prediction model, including random forest (RF), logistic regression, and support vector machine (SVM). Accuracy, precision, recall, and F1 score were used as classification indicators to evaluate the training and validation performance of the model. SHAP values were furthermore used to explore the impacts of features. This study finally included 282 patients, including 164 males (58.16%) and 118 females (41.84%). 69 patients without stenosis, 70 patients with mild stenosis, 65 patients with moderate stenosis, and 78 patients with severe stenosis. Significant differences of tongue parameters were observed in the four groups [TC_R (P = 0.000), TC_G (P = 0.003), TC_H (P = 0.001) and TC_S (P = 0.024),CC_R (P = 0.006), CC_B (P = 0.023) and CC_S (P = 0.001)]. The SVM model had the highest predictive ability, with AUC values above 0.9 in different stenosis groups, and was particularly good at identifying mild and severe stenosis (AUC = 0.98). SHAP value showed that high values of TC_RIGHT_R, low values of CC_LEFT_R were the most impact factors to predict no coronary stenosis; high CC_LEFT_R and low TC_ROOT_H for mild coronary stenosis; low TC_ROOT_R and CC_ROOT_B for moderate coronary stenosis; high CC_RIGHT_G and low TC_ROOT_H for severe coronary stenosis. Tongue color parameters can provide a reference for predicting the degree of coronary artery stenosis. The study provides insights into the potential application of tongue color parameters in predicting coronary artery stenosis severity. Future research can expand on tongue features, optimize prediction models, and explore applications in other cardiovascular diseases.

A systematic study on the phase diagram and superconductivity of ternary clathrate Ca-Sc-H at high pressures.

This work explores potential high-temperature superconductor materials in hydrogen-rich systems. Here, the crystal structure stabilities of ternary Ca-Sc-H systems under high-pressure (P = 100-250 GPa) and their superconductivities are investigated using the particle swarm optimization methodology combined with first-principles calculations. For the predicted candidate structures of Ca-Sc-H systems, the pressure-dependent phase diagram and thermodynamic convex hull were investigated across a wide range of compositions; the electronic properties of all the predicted phases were analyzed in detail to study the bonding behavior of these stable phases. We identified the crystal structures of four thermodynamically stable compounds: R3̄m-CaScH6, Immm-CaSc2H9,C2/m-Ca2ScH10, and R3̄m-CaScH12. Among them, R3̄m-CaScH12 was predicted to have the highest Tc value (i.e., 173 K) at 200 GPa. The discovery of this previously unreported pressure-induced decomposition of Ca-Sc-H systems will pave the way for investigations on the nature of hydrogen-metal interactions.

Tuning the magnetic properties of double transition-metal carbide CoMC (M = Ti, V, Cr, Mn, Fe, Ni) monolayers.

The intrinsic ferromagnetism of two-dimensional transition metal carbide Co2C is remarkable. However, its practical application in spintronic devices is encumbered by a low Curie temperature (TC). To surmount this constraint, double transition-metal carbide CoMC (M = Ti, V, Cr, Mn, Fe, Ni) monolayers are constructed with the aim of improving the magnetic properties and Curie temperature of Co2C. The magnetic properties of CoMC monolayers are comprehensively investigated by first-principles calculations and the effects of hole doping and biaxial strain on the magnetic properties of CoMC (M = V, Cr, Mn) monolayers are also studied. The ground states of CoTiC, CoMnC and CoNiC monolayers all favor ferromagnetic ordering, whereas the CoVC and CoCrC monolayers favor antiferromagnetic ordering and the CoFeC monolayer is non-magnetic. Excitedly, the CoMnC monolayer displays a high total magnetic moment of 4.024μB and a TC of 1366 K. Moreover, the control of hole doping can effectively improve the TC of CoVC, CoCrC, and CoMnC monolayers to 680, 1317, 3044 K, respectively. Finally, applying the in-plain biaxial strain, the CoVC monolayer can be transformed into a ferromagnetic semiconductor under a tensile strain of 6%. The TC values of CoVC, CoCrC, and CoMnC monolayers are tuned by biaxial strain to 440, 1334 and 2390 K, respectively. Their TC above room temperature demonstrates that these monolayers have potential applications in spintronic devices. These theoretical investigations provide valuable insights into guiding experimental synthesis endeavors.

Two-dimensional spin-crossover coordination polymers based on the 1,1,2,2-tetra(pyridin-4-yl)ethene ligand.

A series of two-dimensional (2D) spin-crossover coordination polymers (SCO-CPs) [FeII(TPE)(NCX)2]·solv (1: X = BH3, solv = H2O·2CH3OH·DMF; 2: X = Se, solv = H2O·2CH3OH·0.5DMF; 3: X = S, solv = H2O·2CH3OH·0.5DMF) were synthesized by employing 1,1,2,2-tetra(pyridin-4-yl)ethene (TPE) and pseudohalide (NCX-) coligands. Magnetic measurements indicated that complexes 1-3 exhibited SCO behaviors with diminishing thermal hysteresis (7/4/0 K) upon decreasing the ligand-field strength. The critical temperatures (Tc) during spin transition were found to be inversely proportional to the coordination ability parameters (a™) with a linear correlation. The guest effect was also investigated in the solvent-exchanged phases 1-SE/2-SE/3-SE wherein the DMF molecules were replaced by methanol molecules. Compared with 1-3, 1-SE/2-SE/3-SE displayed more abrupt and complete single-step SCO behaviors but narrower thermal hysteretic loops. The results reported here demonstrate that the Tc values of these two families were dominated by the ligand-field strength of the NCX- anions (NCBH3 > NCSe > NCS), whereas the guest effect only modulated the kinetic factor of the SCO nature in this system.

Comparison of Metabolic Effects of Three Different Treatment Combinations with Retrospective Real-life Data in People Living with HIV.

Comorbidities are increasing in people living with HIV (PLHIV), and different treatment options have advantages and disadvantages. It is important to compare information from real-life treated cases. The aim of this study was to retrospectively evaluate the data on efficacy and clinical and laboratory findings during different antiretroviral therapies. Retrospective file data of 47 PLHIV using Dolutegravir and Lamivudine (3TC/DTG), Tenofovir Alafenamide Emtricitabine and Elvitegravir Cobicistat (EVG/c/TAF/FTC) and Tenofovir Disoproxil Fumarate and Emtricitabine and Efavirenz (EFV/FTC/TDF) were analyzed. Data of the patients at baseline and 12 months after antiretroviral therapy (ART) were compared. About 47 PLHIV were included in the study. Of the patients, 22 (46.8%) were in the 3TC/DTG group, 19 (40.4%) in the EVG/c/TAF/FTC, and 6 (12.8%) in the EFV/FTC/TDF group. After 12 months of treatment, BMI, HIV-RNA, CD4, WBC, hemoglobin, MCV, PDW, RDW, platelet count, creatinine, eGFR, HDL, AST, glucose values of the 3TC/DTG group were significantly different (p<0.05). After 12 months of treatment, BMI, HIV-RNA, CD4 count, MCV, creatinine, eGFR, HDL, LDL, TG, TC, AST, and HOMA-IR values of the EVG/c/TAF/FTC treatment group were significantly different (p<0.05). After 12 months of treatment, HIV RNA, total bilirubin, and LDL values in the EFV/FTC/TDF treatment group were statistically different (p<0.05). All treatment groups showed a decrease in HIV-RNA and an increase in CD4 at the end of one year. While CD4 elevation is lower in EFV recipients than in integrase inhibitor (INSTI) recipients, weight gain is higher in INSTI recipients. While the lipid profile was more positively affected in the 3TC/DTG group, lipid profiles were more negatively affected in the EVG/c/TAF/FTC group, although liver and kidney functions were preserved.

Coastal degradation regulates the availability and diffusion kinetics of phosphorus at the sediment-water interface: Mechanisms and environmental implications

Coastal wetlands have experienced considerable loss and degradation globally. However, how coastal degradation regulates sediment phosphorus (P) transformation and its underlying mechanisms remain largely unknown in subtropical coastal ecosystems. This study conducted seasonal field measurements using high-resolution diffusive gradient in thin films (DGT) and dialysis (Peeper) techniques, as well as a DGT-induced fluxes in sediments (DIFS) model, to evaluate the mobilization and diffusion of P along a degradation gradient ranging from pristine wetlands to moderately and severely degraded sites. We observed that sediment P is diminished by coastal degradation, and severely degraded sites exhibit a decline in the concentration of available P, despite the presence of distinct seasonal patterns. High-resolution data based on DGT/Peeper analysis revealed that labile P and soluble reactive P (SRP) concentrations varied from 0.0006 mg L−1 to 0.084 mg L−1 (mean 0.0147 mg L−1) and from 0.0128 mg L−1 to 0.1677 mg L−1 (mean 0.0536 mg L−1), respectively. Coastal degradation had a substantial impact on increasing SRP and labile P concentrations, particularly at severely degraded sites. Although severely degraded wetlands appeared to be P sinks (negative P flux at these sites), we did also observe positive diffusive flux in October, indicating that coastal degradation may accelerate the diffusion and remobilization of sediment P into overlying water. The simulations of the DIFS model provided compelling proof of the high resupply capacity of sediment P at severely degraded sites, as supported by the increased R and k-1 values but decreased Tc values. Taken together, these results suggest coastal degradation reduces the sediment P pool, primarily attributed to the strong remobilization of P from the sediment to porewater and overlying water by enhancing the resupply capability and diffusion kinetics. This acceleration induces nutrient loss which adversely impacts the water quality of the surrounding ecosystem. To reduce the adverse effects of coastal degradation, it is essential to adopt a combination of conservation, restoration, and management efforts designed to mitigate the risk of internal P loading and release, and ultimately maintain a regional nutrient balance.

The effect of Li/Ce co‐doping on structural and electrical properties of Sr2−x(Li, Ce)x/2Nb2O7 piezoelectric ceramics

AbstractAs a typical perovskite‐like layered structure (PLS) ceramic, Sr2Nb2O7 (SNO) possesses a high Curie temperature TC value above 1300°C, which is expected to work in higher temperature environment. However, pure SNO presents a piezoelectric constant d33 value of ∼ 1 pC/N. Hence, (Li, Ce) ions are doped in SNO ceramics, which increases the distortion of oxygen octahedrons and enhances the intrinsic contribution of piezoelectric properties. The increased domain size with large proportion of high response areas means that the extrinsic contribution is also improved. The introduction of (Li, Ce) ions can also promote ceramic's grain growth and reduce oxygen vacancies, leading to the improvement of electrical properties. The optimal component Sr1.96(Li, Ce)0.02Nb2O7 ceramics exhibit a d33 value of 3.1 pC/N, a higher resistivity of 1.65×106 Ω·cm at 700°C and an excellent thermal stability (a d33 value of 3.0 pC/N after annealing at 1200°C for 2 h). This work provides an effective approach with simple process and low cost for the application of PLS materials in high‐temperature environments.

Calculation of Proper Time of Concentration for Drainage Design in Construction Projects for Urban Development

The design and construction of a proper drainage system are important for any urban development project, small or big. Hydrological and hydraulic calculations are used to design the drainage systems. The calculation of peak flow is one of the common hydrological methods applied to determine the drain sizes for all construction projects. Peak flows and hydrographs can be calculated using several techniques. In order to calculate the peak flow, the design rainfall duration has to be appropriate, which will reflect the critical storm duration. The critical storm duration, on the other hand, depends on the time of concentration (tc) of the catchment. However, most of the equations for tc available in the literature are empirical. At least 23 equations could be traced in various references, which consist of different geophysical and other hydrological parameters. This paper is intended to explain the importance of the proper use of tc to calculate peak runoff flow for construction projects, as accurately as possible. A review of the existing methods used to calculate the time of concentration revealed inconsistencies among a few methods found in the literature. The correct value of the time of concentration (tc) is important for the application of the Rational Method, as the value of tc helps the designer assume the storm duration critical to get the maximum peak flow value. If the critical storm duration is not used in the Rational Method, the drain will be undersized, and the overflow of the storm runoff may happen. Therefore, ample attention should be given to the calculation of the time of concentration to ensure the safety, economy, and sustainability of the drainage system in any development project.

The modifications in structural, optical, and electro-magnetic phase transition of Vanadium-doped La-based manganite ceramics La0.7Pb0.3Mn1−yVyO3 (y = 0 – 0.1)

The present paper is centred around the investigation of the structural, electrical, and magnetic properties displayed by the novel perovskite polycrystalline La0.7Pb0.3Mn1−yVyO3 (y = 0 – 0.1) prepared via the conventional solid-state technique. The structural properties of the samples were assessed through the utilisation of X-ray diffraction (XRD) analysis. Subsequently, the obtained diffraction data underwent refinement employing Rietveld refinement techniques in order to determine the structural parameters of the samples a, b, c, V and Mn–O bond length and angle. The study of X-ray diffraction (XRD) peaks reveals that all the samples exhibited crystallization in a single phase, devoid of any impurities. All of the samples exist in rhombohedral orientation with a space group of R-3c. The tolerance factor of the samples was calculated in order to assess the severity of lattice distortion, decrease from 0.872 (y = 0) to 0.831 (y = 0.1). The microstructural characteristics of the samples were analysed using a field-emission scanning electron microscope (FESEM). The morphology results reveal that a rise in the amount of V leads stimulates the grain growth in the sample, as evidenced by the increase in grain size from 2.17 µm (y = 0) to 3.71 µm (y = 0.1). The Fourier transform infrared (FTIR) analysis revealed an absorption range of 500 – 600 cm-1, which is indicative of the Mn–O bond deformation vibration. This observation suggests the presence of a MnO6 bond in the sample. The Tauc plots derived from the UV-Vis spectroscopy data reveal a notable increase in the optical bandgap (Eopt) as the concentration of V increases. Specifically, the Eopt values rise from 1.71 eV (y = 0) to 2.30 eV (y = 0.1), falling within the range typically observed for semiconductor materials. A distinct metal-insulator transition was observed in all of the samples, exhibiting a range of TMI values ranging from 250 K to 292 K. The scattering model was employed to determine the itinerant eg behaviour in the low temperature region, whilst the SPH model was used to explore the conduction behaviour in the high temperature region. The magnetic characteristic of the samples was investigated using the Alternating Current Susceptibility (ACS) and Vibrating Sample Magnetometer (VSM) techniques, which confirms the existence of a shift in phase from ferromagnetic (FM) to paramagnetic (PM). The TC value exhibits a declining trend from 298.8 K (y = 0) to 274.8 K (y = 0.1).

Polymorphism within IGFBP Genes Affects the Acidity, Colour, and Shear Force of Rabbit Meat

Rabbits are important livestock animals, popular for their nutritional value. Nowadays, the molecular background of traits influencing the quality of meat and meat products is in high demand. Therefore, in the current study, we analyse the sequences of IGFBP1, IGFBP2, IGFBP4, IGFBP5, and IGFBP6 for possible polymorphisms. Based on a bioinformatics analysis in an association study on 466 animals of different breeds (New Zealand White × Flemish Giant crossbreed (9NZWxFG), Termond White (TW), Popielno White (PW), and Flemish Giant (FG)), we analyse the influence of five polymorphisms within the IGFBP genes. Statistically significant differences were found among the carcass and meat quality traits but not for all of the analysed rabbit breeds. The most promising polymorphism was g.158093018A&gt;T within the IGFBP5 gene. The values of pH24 of m.longissimus lumborum (m.l.l.) and biceps femoris muscles (m.b.f.) were higher for the AT genotypes compared to the AA genotypes for the TW and NZWxFG crossbreeds. Also, for pH24, we found differences in ing.41594308T&gt;C for NZWxFG, where the TT genotype values were higher than the TC values. We found differences in L*24 on m.l.l. for g.41592248A&gt;C for NZWxFG. For m.b.f., significant differences were found in b*45 for g.3431insAC in the FG population and a*45 for g.41592248A&gt;C and g.158093018A&gt;T in the TW population. The shear force statistically differed for g.158093018A&gt;T in TW rabbits and g.41592248A&gt;C for NZWxFG. We conclude that this polymorphism may be promising for better quality rabbit meat and may be implemented in selection processes.

Current induced effect on the resistivity in La0.8−xDyxNa0.2MnO3 monovalent doped manganites

The observation of electroresistance, ER effect in several substituted doped manganites which characterized the sensitivity of sample’s resistivity to the change of applied current was suggested can be enhanced by the presence of magnegtic inhomogenity. However, such effect is not well understood but the magnetic inhomogenity may influence the strength of ER related mechanism, hence current induced effect on the resistivity in monovalent doped La0.8−xDyxNa0.2MnO3 (x = 0.00–0.20) manganites prepared using solid state reaction method have been investigated to elucidate the matter. The ρ vs T curves shown that all samples exhibit smaller resistivity under higher applied current of 10 mA as compared to 5 mA of applied current in the wide temperature range of 30 K–300 K which led to ER effect. Measurement of ac susceptibility show that x = 0 sample exhibit ferromagnetic behaviour while both Dy substituted samples exhibit ferromagnetic to paramagnetic transition behavior with reduction in Tc values. Large ER effect with value of 130% at 300 K observed in ER vs. T curve for x = 0.1 sample, while for x = 0 the ER value is 9% indicates improved sensitivity of the Dy substituted sample towards electric field. While x = 0.20 sample exhibit double ER peaks which may related to presence of impurity phases. It is suggested Dy substitution induces magnetic inhomogeneities which favors formation of more filamentary conductive paths under the presence of high applied current thus enhanced the conduction process of charge carriers. The finding on the enhancement of ER effect indicates that the Dy substituted sample as potential candidates for spintronic-based devices.

Sampling the Materials Space for Conventional Superconducting Compounds.

A large scale study of conventional superconducting materials using a machine-learning accelerated high-throughput workflow is performed, starting by creating a comprehensive dataset of around 7000 electron-phonon calculations performed with reasonable convergence parameters. This dataset is then used to train a robust machine learning model capable of predicting the electron-phonon and superconducting properties based on structural, compositional, and electronic ground-state properties. Using this machine, the transition temperatures (Tc ) of approximately 200000 metallic compounds are evaluated, all of which are on the convex hull of thermodynamic stability (or close to it) to maximize the probability of synthesizability. Compounds predicted to have Tc values exceeding 5K are further validated using density-functional perturbation theory. As a result, 541 compounds with Tc values surpassing 10K, encompassing a variety of crystal structures and chemical compositions, are identified. This work is complemented with a detailed examination of several interesting materials, including nitrides, hydrides, and intermetallic compounds. Particularly noteworthy is LiMoN2 , which is predicted to be superconducting in the stoichiometric trigonal phase, with a Tc exceeding 38K. LiMoN2 has previously been synthesized in this phase, further heightening its potential for practicalapplications.

Theoretical study on superconductivity of Ce–Ca–H ternary hydrides under high pressure

In this work, we used genetic algorithm combined with density functional theory (DFT) calculations to search for the structures of the pressure-induced ternary hydrides CeCaxHy (x=1–3, y = 1–24). The crystal structures and electronic properties of CeCaxHy in the pressure range of 100–300 GPa were systematically studied. The calculated results showed that structures of P4/mmm-CeCaH8, Cmmm-CeCaH8, Cmmm-CeCaH12 and Fm-3m-CeCa3H24 could be stable in pressure range of 150–300 GPa. The predicted superconducting transition temperature (Tc) values were 90, 86 and 150 at 150 GPa for P4/mmm-CeCaH8, Cmmm-CeCaH8 and Cmmm-CeCaH12, respectively, and the Fm-3m-CeCa3H24 structure had a Tc of 201 K at 300 GPa. Also, the mechanical properties of the Ce–Ca–H most stable phases were discussed.

Analysis of superconducting critical temperature using numerical method

Currently, many studies have shown that the critical temperature (Tc) of a superconductor can be predicted by using the BCS theory. In this work, we analyse Tc of superconductors, which is determined by the spectral function (α2F(ω)) derived from the interaction between electrons and phonons. The equation that we used for the calculation is Tcstrong=f1f2Tcweak . In this equation, Tcweak refers to the Allen-Dynes formula and f is the correction factor. We compare the Tc obtained from this equation with our method. Many important parameters are given and analysed, such as average coupling strength (λ), the square root of the average frequency square (ω2), and average logarithm frequency (ωln). We use numerical methods and expect to improve the equation to calculate Tc to be user-friendly. Normally, the calculation of Tc can be challenging and time-consuming. The most successful theory explaining the general properties of superconductors is the BCS theory. It explains the mechanism in which normal conductors become superconductors, and the pairing of electrons known as the Cooper pairing is formed by the electron-phonon interactions. In the past, the BCS theory predicted the limit of the critical temperature of superconductors to be around 30-40 kelvin. Recently, several researchers have been discovered a higher Tc value than the limited value from experiments under high pressure. Our method could provide a better analysis of appropriate Tc of superconductors to support new discoveries in the future.

Pressure-induced superconductivity in tantalum superhydrides

The quest for high-temperature superconductivity in pressure-stabilized hydrides has received great interests due to the recent findings of CaH6, LaH10, YH6, YH9 and H3S with superconducting critical temperature, Tc, above 200 K and at a pressure range of 155–201 GPa. In this work, we conduct extensive structure-searching simulations for the Ta–H system at a pressure range of 300–400 GPa. As a result, we predict several stable pressure-stabilized phases, such as TaH10, TaH11, TaH16 and TaH17. These predicted structures consist of molecular and atomic hydrogen units, where the latter holds the key to improve the superconductivity of the system. Among these high-Tc candidates, tetragonal TaH16 phase, with the large hydrogen content of ∼84 %, exhibits a high Tc value of 196 K at 400 GPa. Our current results could be helpful for the future design of high-temperature superconductivity in the system of transition metal superhydrides under high pressure.

Effect of Cr substitution on structural, magnetic, magnetocaloric and critical behaviors of La0.7Y0.05Ba0.25MnO3 perovskite manganite

A thorough investigation was conducted into the structural, magnetic, and critical properties of La0.7Y0.05Ba0.25Mn1-xCrxO3 (x = 0 and 0.15) perovskite manganite synthesized using the sol-gel method. The samples possess an orthorhombic structure with the Pnma space group according to X-ray diffraction (XRD) patterns. The average ion radii of the B-site cation (<rB>), the unit cell volume (V), and <θMn,Cr–O–Mn,Cr > bond angle decreased with Cr substitution. While the average bond distance, <dMn,Cr–O>, and Goldschmidt tolerance factor (tG) increased. The samples present a magnetic transition from a paramagnetic (PM) phase to a ferromagnetic (FM) phase at Curie temperature (TC). Addition of Cr to La0.7Y0.05Ba0.25MnO3 decreased the TC value from 310 K (for x = 0 sample) to 258 K (for x = 0.15 sample). Using Banerjee's criteria, second-order phase transitions were determined for the samples. Both samples showed significant maximum entropy change |ΔSMmax| and relative cooling power (RCP) whose values decreased from (6.40 J Kg−1 K−1 and 231 J Kg−1 for x = 0) to (4.45 J Kg−1 K−1 and 185 J Kg−1 for x = 0.15), respectively. These values indicate that the La0.7Y0.05Ba0.25Mn1-xCrxO3 manganites exhibit favourable magnetocaloric effect (MCE) and demonstrate promising potential for application as materials in magnetic refrigeration technology. The estimated critical exponents (β, γ, and δ) for the x = 0 sample align with the 3D-Ising model, while for x = 0.15, they closely resemble the 3D-Heisenberg model. This shift in the universality class can be attributed to the interplay between competing ferromagnetic double-exchange and antiferromagnetic super-exchange interactions that exist within the prepared samples.

Synthesis of superconducting phase of La0.5Ce0.5H10 at high pressures

Clathrate hydride -LaH10 has been proven as the most extraordinary superconductor with the critical temperature Tc above 250 K upon compression of hundreds of GPa in recent years. A general hope is to reduce the stabilization pressure and maintain the high Tc value of the specific phase in LaH10. However, strong structural instability distorts structure and leads to a rapid decrease of Tc at low pressures. Here, we investigate the phase stability and superconducting behaviors of -LaH10 with enhanced chemical pre-compression through partly replacing La by Ce atoms from both experiments and calculations. For explicitly characterizing the synthesized hydride, we choose lanthanum-cerium alloy with stoichiometry composition of 1:1. X-ray diffraction and Raman scattering measurements reveal the stabilization of -La0.5Ce0.5H10 in the pressure range of 140–160 GPa. Superconductivity with Tc of 175 ± 2 K at 155 GPa is confirmed with the observation of the zero-resistivity state and supported by the theoretical calculations. These findings provide applicability in the future explorations for a large variety of hydrogen-rich hydrides.

Melt Spinning Process Optimization of Polyethylene Terephthalate Fiber Structure and Properties from Tetron Cotton Knitted Fabric.

Polyester/cotton fabrics with different proportions of Tetron Cotton, TC (35% Cotton/65% PET), and Chief Value Cotton, CVC (60% Cotton/40% PET), were investigated by removing the cotton component under various phosphoric acidic conditions including the use of cellulase enzymes. The remaining polyethylene terephthalate (PET) component was spun using the melt spinning method. Only 85% H3PO4-Enz_TC could be spun into consistent filament fibers. The effects of Acid-Enz TC (obtained from a powder preparation of 85% H3PO4-Enz_TC) at different weight amounts (1, 2, 5, and 10 %wt) blending with WF-rPET powder prepared by white recycled polyester fabric were evaluated for fiber spinnability at different winding speeds of 1000 and 1500 m/min. The results revealed that recycled PET fiber spun by adding Acid-Enz_TC up to 10 %wt gave uniformly distributed filament fibers. A comparative study of the physical, thermal, and mechanical properties also investigated the relationship between the effect of Acid-Enz_TC and the structure of the obtained fibers. Acid-Enz_TC:WF-rPET (5:95) was the optimal ratio. The thermal values were analyzed by DSC and TGA and crystallinity was analyzed by XRD, with mechanical strength closed to 100% WF-rPET. The FTIR analysis of the functional groups showed the removal of cotton from the blended fabrics. Other factors such as the Acid-Enz_TC component in WF-rPET, extraction conditions, purity, thermal, chemical, and exposure experiences also affected the formability and properties of recycled PET made from non-single-component raw materials. This study advanced the understanding of recycling PET from TC fabrics by strategically removing cotton from polyester-cotton blends and then recycling using controlled conditions and processes via the melt spinning method.

Hydrogen peroxide assisted advanced electrocoagulation for reducing the organic content of leachate nanofiltration concentrate

Integrated biological treatment-membrane filtration is widely applied in leachate treatment to ensure discharge standards. The most important waste of this integrated application is high volumes of membrane concentrate. In this study, the treatment of leachate nanofiltration concentrate (NFC) with high resistive organic matter content was investigated by hydrogen peroxide (HP) assisted advanced electrocoagulation process (EC-HP) using Al electrodes. To achieve maximum pollutant removal efficiencies, process optimization was carried out using the Box-Behnken design (BBD). Statistically, the fit of the model was evaluated by analysis of variance. Correlation coefficients (R2) of all mathematical models developed for system responses (COD, UV254, TOC, and color removal efficiency) with EC-HP process were close to 1, adjusted R2 values were close to R2 values, and the difference between adjusted R2 and predicted R2 values was less than 0.2. These values indicate that the BBD method is effective, appropriate, and meaningful in explaining the pollutant removal from leachate NFC with the EC-HP process. Under the optimized conditions (27.3 mM HP, 0.6 A, pH 5, and 45 min) 62.2 %, 55.3 %, 73.9 %, and 85.9 % COD, TOC, UV254, and color removal efficiencies, respectively were predicted by the model and by validation study, 57.3 % COD, 52.0 % TOC, 68.3 % UV254, and 85.0 % color removal yields were achieved. SEC and SECCOD values were calculated as 7.65 kWh/m3 and 2.78 kWh/kgCOD, respectively at optimum conditions. Moreover, ENC, ELC, CC, and TC values were 0.55 $/m3, 0.82 $/m3, 8.0 $/m3, and 9.37 $/m3, respectively. The results of the study showed that the EC-HP process is an effective method for pollutant removal from leachate NFC.