Change In Chemical Potential Research Articles

Effects of calcium ions and polysaccharides type on transparent exopolymer particle formation and the related fouling mechanisms

Organics and divalent cations are the primary barriers constraining the performance of membrane technology, while the interactions between them and the detailed mechanisms of their impacts are still lacking in-depth analysis. In this study, sodium alginate and xanthan gum were selected as polysaccharides models, and the formation of transparent extracellular polymer particles (TEP) was assessed to examine the effect of Ca2+ and polysaccharides type on membrane fouling from both qualitative and quantitative perspectives. The results revealed that higher Ca2+ concentrations led to a greater abundance of TEP, and the transformation of TEP microstructure is a key factor for the membrane fouling change indicated by specific filtration resistance (SFR). TEP formed by sodium alginate underwent a transformation from amorphous-TEP (a-TEP) form to particle-TEP (p-TEP), corresponding to a unimodal pattern of SFR variation. With increasing Ca2+ concentration, the molecular interactions of xanthan gum became stronger, resulting in larger fibrous a-TEP and a continuous SFR increase. According to the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, TEP formed by xanthan gum exhibited higher adhesion energy, thus causing more severe membrane fouling. The SFR variation of the TEP system can be satisfactorily explained by the conception of chemical potential change in the filtration process depicted in Flory-Huggins theory. This study is the first work to introduce models regarding chemical potential and TEP microstructure, linking the system chemical potential and TEP microstructure with membrane fouling indicated by SFR. As all, this study provided a new perspective for analyzing the polysaccharide fouling behavior via TEP determination and further enhanced the understanding through thermodynamic analysis.

Variations in fluid chemical potential induce fibroblast mechano-response in 3D hydrogels

Mechanical deformation of skin creates variations in fluid chemical potential, leading to local changes in hydrostatic and osmotic pressure, whose effects on mechanobiology remain poorly understood. To study these effects, we investigate the specific influences of hydrostatic and osmotic pressure on primary human dermal fibroblasts in three-dimensional hydrogel culture models. Cyclic hydrostatic pressure and hyperosmotic stress enhanced the percentage of cells expressing the proliferation marker Ki67 in both collagen and PEG-based hydrogels. Osmotic pressure also activated the p38 MAPK stress response pathway and increased the expression of the osmoresponsive genes PRSS35 and NFAT5. When cells were cultured in two-dimension (2D), no change in proliferation was observed with either hydrostatic or osmotic pressure. Furthermore, basal, and osmotic pressure-induced expression of osmoresponsive genes differed in 2D culture versus 3D hydrogels, highlighting the role of dimensionality in skin cell mechanotransduction and stressing the importance of 3D tissue-like models that better replicate in vivo conditions. Overall, these results indicate that fluid chemical potential changes affect dermal fibroblast mechanobiology, which has implications for skin function and for tissue regeneration strategies.

Redox dynamics and surface structures of an active palladium catalyst during methane oxidation

Catalysts based on palladium are among the most effective in the complete oxidation of methane. Despite extensive studies and notable advances, the nature of their catalytically active species and conceivable structural dynamics remains only partially understood. Here, we combine operando transmission electron microscopy (TEM) with near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and density functional theory (DFT) calculations to investigate the active state and catalytic function of Pd nanoparticles (NPs) under methane oxidation conditions. We show that the particle size, phase composition and dynamics respond appreciably to changes in the gas-phase chemical potential. In combination with mass spectrometry (MS) conducted simultaneously with in situ observations, we uncover that the catalytically active state exhibits phase coexistence and oscillatory phase transitions between Pd and PdO. Aided by DFT calculations, we provide a rationale for the observed redox dynamics and demonstrate that the emergence of catalytic activity is related to the dynamic interplay between coexisting phases, with the resulting strained PdO having more favorable energetics for methane oxidation.

Two‐Dimensional Heterostructure Complementary Logic Enabled by Optical Writing

Integrated logic circuits using atomically thin, two‐dimensional (2D) materials offer several potential advantages compared to established silicon technologies such as increased transistor density, circuit complexity, and lower energy dissipation leading to scaling benefits. In this article, a novel approach to achieve tunable doping in 2D semiconductors is explored to achieve complementary transistors and logic integration. By selectively transferring WSe2 onto hBN and SiO2 substrates, complementary transistor behavior (n‐ and p‐type) was achieved using a UV light source and electrostatic activation. Furthermore, advanced characterization techniques, including high‐resolution transmission electron microscopy (HRTEM) and Kelvin probe force microscopy (KPFM), provided insights into the chemical composition and surface potential changes after UV writing. Finally, a logic inverter was successfully implemented using selectively photo‐induced doped WSe2 transistors, showcasing the potential for practical logic applications. This innovative method opens new avenues for designing energy‐efficient and reconfigurable 2D semiconductor circuits, addressing key challenges in modern electronics.

Effects of hyperon potentials and symmetry energy in quark deconfinement

In this letter we discuss how the results of recent nuclear experiments that correspond to measurements at low densities can affect the equation of state at large densities 4: and temperatures, changing the particle composition and ultimately influencing deconfinement to quark matter. In particular, saturation values of the hyperon potentials affect the hyperon content, while the symmetry energy at saturation directly regulates how the stiffness of the equation of state changes with isospin. We make use of a chiral model that describes nucleons, hyperons, and quarks to show how astrophysical conditions, such as the ones in neutron stars, present the ideal ground to study the effects of these two quantities in dense matter. In this case, for small charge fraction/large isospin asymmetry, the couplings that reproduce different symmetry energy slopes can significantly modify deconfinement, with quantitative changes in the critical chemical potential depending on the deconfining potential. On the other hand, different values of the parameter that controls the hyperon potentials 7: (kept within a range close to experimental data) do not affect deconfinement significantly.

Design and investigation on polarization insensitive dual band graphene based tunable absorber for THz applications

In this communication, a metal-free graphene-based Absorber is designed and examined in the THz regime. The graphene layer is coated over the SiO2 substrate, while the silver layer is used on the other side of the substrate. The designed absorber works in two frequency bands i.e. 2.2–2.91 THz (11–14 μm) and 4.85–5.83 THz (51–62 μm), having more than 90% absorption. Peak absorption is obtained 2.55 THz and 5.05 THz with 97.78% and 99.71% absorption. With the help of circular sectoring, the designed absorber shows wide polarization and wide incident angle (up to 60°) insensitivity for both TE and TM modes. Change in chemical potential of graphene provides the tunable characteristics in the designed absorber. All these outcomes confirm that the designed metal-free graphene-based metamaterial absorber works efficiently in THz regime and can be used in different applications such as, sensing and imaging.

Manganese-oxide-supported gold catalyst derived from metal-organic frameworks for trace PCl3 oxidation in an organic system.

Polysilicon is widely used in the field of semiconductors and solar energy. Trichlorosilane feedstocks that are used to produce polysilicon in the mainstream production process contain PCl3 impurities that have adverse effects on the quality of the polysilicon. Traditional methods for dephosphorization cannot achieve the effect of complete removal, whereas oxidizing PCl3 to POCl3 in the presence of oxygen for removal via adsorption is a promising and appealing route for establishing a dephosphorization process; it has a high phosphorous removal rate due to the strong Lewis-base property of POCl3 in comparison with PCl3. In this work, we synthesized an active catalyst with an active interface between Au nanoparticles (NPs) and a manganese-oxide support (Mn3O4) by calcination of a corresponding composite, where Au NPs were embedded uniformly in a metal-organic framework (MOF). The catalyst shows a significantly active catalytic performance for trace PCl3 oxidation in an organic system that is an imitation of a trichlorosilane system, with a 99.13% yield of POCl3 in an 80 °C and 0.6 MPa reaction environment. The structure-performance-mechanism analysis shows that the possible reaction and catalytic mechanism is PCl3 oxidation by interface lattice oxygens, which bridge the Au NPs and the support, in a Mars van Krevelen (MvK) process; this process was promoted by the interaction between the Au NPs and Mn3O4 in terms of charge transfer and chemical potential changes. This work provides an effective way to dephosphorize trichlorosilane feedstocks in the polysilicon industry and gives guidance for constructing an efficient catalyst via the study of the structure and mechanism.

Albumin Protein Impact on Early-Stage In Vitro Biodegradation of Magnesium Alloy (WE43).

Mg and its alloys are promising biodegradable materials for orthopedic implants and cardiovascular stents. The first interactions of protein molecules with Mg alloy surfaces have a substantial impact on their biocompatibility and biodegradation. We investigate the early-stage electrochemical, chemical, morphological, and electrical surface potential changes of alloy WE43 in either 154 mM NaCl or Hanks' simulated physiological solutions in the absence or presence of bovine serum albumin (BSA) protein. WE43 had the lowest electrochemical current noise (ECN) fluctuations, the highest noise resistance (Zn = 1774 Ω·cm2), and the highest total impedance (|Z| = 332 Ω·cm2) when immersed for 30 min in Hanks' solution. The highest ECN, lowest Zn (1430 Ω·cm2), and |Z| (49 Ω·cm2) were observed in the NaCl solution. In the solutions containing BSA, a unique dual-mode biodegradation was observed. Adding BSA to a NaCl solution increased |Z| from 49 to 97 Ω·cm2 and decreased the ECN signal of the alloy, i.e., the BSA inhibited corrosion. On the other hand, the presence of BSA in Hanks' solution increased the rate of biodegradation by decreasing both Zn and |Z| while increasing ECN. Finally, using scanning Kelvin probe force microscopy (SKPFM), we observed an adsorbed nanolayer of BSA with aggregated and fibrillar morphology only in Hanks' solution, where the electrical surface potential was 52 mV lower than that of the Mg oxide layer.

Dissociation line and driving force for nucleation of the nitrogen hydrate from computer simulation

In this work, we determine the dissociation line of the nitrogen (N2) hydrate by computer simulation using the TIP4P/Ice model for water and the TraPPE force field for N2. We use the solubility method proposed recently by some of us to evaluate the dissociation temperature of the hydrate at different pressures, from 500 to 1500 bar. Particularly, we calculate the solubility of N2 in the aqueous solution when it is in contact with a N2-rich liquid phase and when in contact with the hydrate phase via planar interfaces as functions of temperature. Since the solubility of N2 decreases with temperature in the first case and increases with temperature in the second case, both curves intersect at a certain temperature that determines the dissociation temperature at a given pressure. We find a good agreement between the predictions obtained in this work and the experimental data taken from the literature in the range of pressures considered in this work. From our knowledge of the solubility curves of N2 in the aqueous solution, we also determine the driving force for nucleation of the hydrate, as a function of temperature, at different pressures. In particular, we use two different thermodynamic routes to evaluate the change in chemical potential for hydrate formation. Although the driving force for nucleation slightly decreases (in absolute value) when the pressure is increased, our results indicate that the effect of pressure can be considered negligible in the range of pressures studied in this work. To the best of our knowledge, this is the first time the driving force for nucleation of a hydrate that exhibits crystallographic structure sII, along its dissociation line, is studied from computer simulation.

Computational characterization of structural, optoelectronic and thermoelectric properties of some double half-Heusler alloys X2FeY′Sb2 (X: Hf, Zr ;Y′: Ni, Pd)

ABSTRACT A full-potential linear augmented plane wave (FP-LAPW) has been used to study the structural, electronic, and optical properties of double half-Heusler alloys X2FeY′Sb2 with X≡Zr, Hf and Y′≡Pd, Ni. Electronic band structures and densities of states calculations of the four studied double half-Heusler alloys indicate that they are semiconductors with an indirect gap. The optical spectra of dielectric constants, refractive indices, reflectivity, and light absorption are also discussed. In the energy range of 8–14 eV, the calculated optical properties and mainly the absorption spectrum show very high UV absorption. Additionally, DFT calculations were combined with Boltzmann transport theory to estimate the thermoelectric properties, such as the thermal and electrical conductivity, Seebeck coefficient, and figure of merit (ZT), versus the change of temperature and chemical potential. These alloys possess a suitable band gap for diverse optoelectronic applications, encompassing photovoltaics, UV sensors, and solar cells.

Anisotropic optical conductivities of model topological nodal-line semimetals

With the use of simple models, we investigated the optical conductivity of a nodal-line semimetal (NLSM) whose crossing of the conduction and valence bands near the origin (O point) in the () plane of a small cubic region can be adjusted by a parameter α. The Hamiltonian of the NLSM is based on the model for the low-lying energy bands. When α = 0, these bands touch each other along a continuous closed loop but the opening of a band gap corresponding to finite values of α and the varying of the carrier concentration can be adjusted. This provides a tunable semiconductor gap, around the O point and the valence and conduction bands can meet at a pair of points within the small cubic region in k space. The optical conductivity of such a NLSM is calculated using the Kubo formula with emphasis on the optical spectral weight redistribution, deduced from appropriate Green’s functions, brought about by changes in gap and chemical potential due to modifying α. We derived closed-form semi-analytic expressions for the longitudinal components of the optical conductivity for these model systems of NLSM and compare results for chosen α and chemical potential. We also present results for the heat capacity when the system is in thermal equilibrium for various chosen α and chemical potential.

Solid-source metal-organic MBE for elemental Ir and Ru films

Thin films of elemental metals play a very important role in modern electronic nano-devices as conduction pathways, spacer layers, spin-current generators/detectors, and many other important functionalities. In this work, by exploiting the chemistry of solid metal-organic source precursors, we demonstrate the molecular beam epitaxy synthesis of elemental Ir and Ru metal thin films. The synthesis of these metals is enabled by thermodynamic and kinetic selection of the metal phase as the metal-organic precursor decomposes on the substrate surface. Film growth under different conditions was studied using a combination of in situ and ex situ structural and compositional characterization techniques. The critical role of substrate temperature, oxygen reactivity, and precursor flux in tuning film composition and quality is discussed in the context of precursor adsorption, decomposition, and crystal growth. Computed thermodynamics quantifies the driving force for metal or oxide formation as a function of synthesis conditions and changes in chemical potential. These results indicate that bulk thermodynamics are a plausible origin for the formation of Ir metal at low temperatures, while Ru metal formation is likely mediated by kinetics.

Role of site–site interaction on the phase equilibria of multiple-site associating fluids in a functionalized slit pore

Vapor–liquid phase equilibria for multiple sites associating fluids with different associating strengths are investigated in a slit pore using grand-canonical transition matrix Monte Carlo method. The increase of critical temperature from two-site to four-site associating fluids at constant site strength is quite significant as compared to that of the one-site to two-site associating fluids, which is more pronounced at higher associating strength (ϵ* = 6). Monomer fraction and cluster size distribution are used to investigate the association of fluid particles in coexistence phases. The monomer fraction for both phases decreases with increased associating sites on the fluid particles due to more site–site interaction with neighboring fluid particles and forming a larger cluster. Therefore, the number of associating sites and their distribution play a vital role in the association of fluid particles. Moreover, the saturation chemical potential changes with the arrangement of the sites. For two-site associating fluids, we observe early vapor–liquid transition when the sites are oppositely placed, and when the sites are placed at 90°, the vapor–liquid transition is observed at the higher chemical potential. Moreover, four-site associating fluids with a square arrangement show early vapor–liquid phase transition, mainly because these arrangements of sites effectively interact with surface sites and the molecules in the next layer.

(Digital Presentation) Experimental Results on the Determination of the Billiter Potential

The experimental effects at the Billiter potential are measured in narrow intervals of the equilibrium potentials (A, B). The Billiter potential + 0.475 V SHE [1-3] is confirmed by the following experimental results [4,5,7- 9]. The change in the direction of the current between a dropping mercury and a mercury bottom in solutions of redox systems Fe(CN)6 3 - - Fe(CN)6 4 - and quinone-hydroquinone at a given potential E equil . = + 475 V SHE has been established with exactness ± 1-2 mV [4, 5]. This result was confirmed in [6]. At E equil. > +0.475 V SHE, the current flows from a mercury bottom to dropping electrode and at E equil. < +0.475 V SHE - in the opposite direction. Electrocapillary curves have been found by drop-weight method in these solutions in narrow range E equil. ~+0.4 ÷+0.55 V SHE with a maximum at E equil. ~ + 0.475 V SHE [4].A self-recording galvanometer was used to record the reversal of the current between a mercury bottom and a dropping electrode in solutions of redox systems [7-9]. In a solution of quinone-hydroquinone redox system, a recorded positive current decreases exactly to zero at E = + 228 mV SCE (+ 475 mV SHE), and then a negative current increases with continuous dropping of mercury. E equil. changes by itself since an adsorbed quinone on mercury drops are removed from solution onto mercury bottom (A).The current reversal at E ~+ 0.22 ÷ + 0.23 V SCE (~+0.475 V SHE) has been recorded by a recorder between a mercury bottom and a dropping electrode in acidified Hg2(NO3)2 solutions with the addition of complexing agents (triethanolamine, sodium ethylenediaminetetraacetate, thiocarbamide, others) [7-9].The electrocapillary curves (ECC) have been measured by weight-drop method in these solutions (B; with sodium ethylenediaminetetraacetate). After passing the electrocapillary maximum for reversible Hg2 2+/ Hg electrode at E ~ + 0.22 ÷ + 0.23 V SCE, we have obtained an ascending branch of ECC of an ideally polarizable electrode at E equil. < ~+0.190 ÷ +0.210 V SCE. A registered second current reversal at these E equil. corresponds to the transition from a small descending branch of ECC of Hg2 2+/Hg electrode to an ascending branch of ECC of an ideally polarizable electrode. The electrocapillary maximum was also obtained using diluted acidified solutions of Hg2(NO3)2.An increase in a polarization resistance and a change in polarization capacitance have been detected when impedance measuring with reversible electrodes at Ee ~ +0.475 V SHE. These effects were also measured on mercury drops in the diluted 10-10 N solution of Hg2(NO3)2 + 0.1÷ 0.001 N KNO3 The increase in polarization resistance was explained by the achievement of chemical equilibrium of half-reactions at Ee quil. ~ +0.475 V SHE [6,7,16].Measurements by the immersion method with redox systems and solid electrodes of the second kind confirm the reversal of the current at E ~+ 475 V SHE. Submersible small solid electrodes must be absolutely clean and dry [5]. This method is under development.According to [8 - 10], Billiter potential corresponds to some electrode with zero chemical activity (transitional from metals to non-metals with the intermediate electron work function 5.19 eV). The same zero activity is obtained at chemical equilibrium of half-reactions when the sum of changes of chemical potentials of electrons and ions Δμion + Δμelectron = 0, and potential drops in double - electric layers are compensated. The components Δμion= 0 and Δμelectron≠ 0 correspond to potentials of zero charge Ep. z.c. For mercury, the electron work function is 4.52 eV and Δμelectron = 4.52 eV - 5.19 eV = - 0.67 eV. In order Δμion + Δμelectron = 0, Δμion should be equal + 0.67 eV. Indeed, if E p.z.c. = - 0.193 V SHE for mercury is changed by + 0.67 V we obtain the chemical equilibrium of half-reactions at ~ +0.475 V SHE. REFERENCES J.Billitzer, Methods for Determination of the Absolute Potentials, Trans. Amer. Electrochem. Soc., 1930,57, 351.The Encyclopedia of Electrochemistry, C.A. Hampel (ed.), (Reinhold,New York, NY) (1964).H.J.Oel, H Strelow,Z. Electrochem, 1954,58,665.A.I.Chernomorskii, Soviet Electrochemistry, 1981, 17, 874.A.I.Chernomorskii, Russian Journal of Physical Chemistry,1981, 55, p.206.Ya.I.Tur’yan, Redox Reactions and Potentials in Analytical Chemistry, Khimiya, Moscow, 1989.A.I. Chernomorskii,N.S.Polizan, Reports of Academy of Sciences of the Uzbekistan,1990, 6, 35.A.I.Chernomorskii, Thernodynamics of Electrodes, FAN, Tashkent, 1993.A.I.Chernomorskii, The Intermediate Electron Bond and Half-reactions, Scientific Resources, New York, 1999.A.I. Chernomorskii, Journal of The Electrochemical Society, 2021, 168,116514. Figure 1

Investigation on Reaction Mechanism in an SOFC Composite Cathode by Using Patterned Thin Film Electrodes

Introduction For the further commercial use of solid oxide fuel cells (SOFCs), operating at intermediate temperatures is demanded. When reducing the operating temperature, the degradation of cathodic activity occupies the largest part of degradation of cell performance. Therefore, to improve the performance of SOFCs at intermediate temperature, the activity of cathodic reaction has to be improved.The cathodic reaction of SOFCs proceeds not only at triple phase boundaries (TPBs) of electrode, electrolyte and gas but also at double phase boundaries (DPBs) of electrode and gas, when a mixed ionic and electronic conductor (MIEC) is used. Thus, increasing the DPB area is considered as the best way to improve the cathodic performance. However, it was reported that composite cathodes of MIEC and electrolyte particles showed better performance than simple MIEC cathodes, despite the DPB area decreased [1]. Possible reasons for such performance enhancement can be considered as (i) promotion of oxide ion diffusion and/or (ii) the increase of TPB concentration. However, the reason for the performance enhancement by making a composite cathode are not-well understood so far.In this study, we aimed to understand the cathodic reaction in a composite cathode of MIEC and electrolyte. For this purpose, we proposed new types of original model electrodes to simulate the reaction in actual porous composite electrodes. From electrochemical and the operando X-ray absorption spectroscopic measurements of the model electrodes, we tried to separately evaluate the contribution of ion diffusion and TPB reactions on the performance improvement of composite cathode. Methods When using a porous electrode, it is difficult to investigate the reaction mechanism because of its complicated microstructures. Our research group proposed so-called “patterned thin film model electrode” like Figure 1(a) as a model electrode to reproduce the reaction in a porous electrode while removing the influence of microstructure [2]. In this model electrode, the contact area of electrode and electrolyte was limited by partially inserting an insulating layer, and thus the reaction distribution was formed in the electrode as a function of the distance from the electrode/electrolyte interface.In this study, we proposed two new types of model electrodes as Figure 1(b) and 1(c) to simulate the porous composite electrode. In the patterned composite electrode (b), an electrolyte layer was inserted between the electrode and insulator. On the other hand, in the patterned composite electrode (c), a part of electrode was removed to introduce TPBs. From the difference between the model electrodes (a) and (b), the contribution of oxide ion diffusion in composite electrode was estimated. From the difference between the model electrodes (b) and (c) the contribution of the TPB reaction was estimated. In this study, we selected La0.6Sr0.4CoO3-δ (LSC64) as an MIEC cathode and Gd0.1Ce0.9O2-δ (GDC10) as an electrolyte material. Operando micro X-ray absorption spectroscopy (μ-XAS) measurement was conducted with the model electrodes to investigate the effective reaction area of the model electrode. In this measurement, a change in the oxygen chemical potential can be detected as a change of X-ray absorbance at the fixed energy near the Co K-edge accompanying a change of the oxidation state of Co in the LSC64 [3]. Thus, the reaction distribution could be evaluated by measuring the change of the X-ray absorbance due to the polarization as a function of the distance from the electrode/electrolyte interface. Results and Discussion Figure 2 shows the results of μ-XAS measurement at 973 K under 1 bar O2 with cathodic polarization. The area where the ratio of absorbance is larger than 1 corresponds to the area where the oxygen chemical potential is changed due to the polarization, i.e. the effective reaction area. The reaction area of the model electrode (b) was longer than that of the model electrode (a). This suggested oxide ion diffusion was improved by inserting the GDC layer. On the other hand, the reaction area of the model electrode (c) was longer than that of the model electrode (b). Generally, the reaction on the mixed conducting LSC64 electrode is supposed to proceed DPB reaction mainly. However, the longer reaction area of model electrode (c) indicated that the contribution of TPB reaction was also significant in the LSC64 composite electrode. As a conclusion, both promotion of oxide diffusion and the increase of TPB effective for the enhancement of the cathodic reaction in MIEC composite electrode.[1] Y. T. Kim, et al., Solid State Ionics, 309, 77-85 (2017).[2] K. Amezawa, et al., ECS transactions, 62(2), 129-135 (2015).[3] Y. Orikasa, et al., Journal of Physical Chemistry C, 115, 16433–16438 (2011). Figure 1

Chiral-Flux-Phase-Based Topological Superconductivity in Kagome Systems with Mixed Edge Chiralities.

Recent studies have attracted intense attention on the quasi-2D kagome superconductors AV_{3}Sb_{5} (A=K, Rb, and Cs) where the unexpected chiral flux phase (CFP) associates with the spontaneous time-reversal symmetry breaking in charge density wave states. Here, commencing from the 2-by-2 charge density wave phases, we bridge the gap between topological superconductivity and time-reversal asymmetric CFP in kagome systems. Several chiral topological superconductor (TSC) states featuring distinct Chern numbers emerge for an s-wave or a d-wave superconducting pairing symmetry. Importantly, these CFP-based TSC phases possess unique gapless edge modes with mixed chiralities (i.e., both positive and negative chiralities), but with the net chiralities consistent with the Bogoliubov-de Gennes Chern numbers. We further study the transport properties of a two-terminal junction, using Chern insulator or normal metal leads via atomic Green's function method with Landauer-Büttiker formalism. In both cases, the normal electron tunneling and the crossed Andreev reflection oscillate as the chemical potential changes, but together contribute to plateau transmissions (1 and 3/2, respectively) that exhibit robustness against disorder. These behaviors can be regarded as the signature of a TSC hosting edge states with mixed chiralities.

Novel thermodynamic mechanisms of co-conditioning with polymeric aluminum chloride and polyacrylamide for improved sludge dewatering: A paradigm shift in the field

This study investigated the combined effects of polymeric aluminum chloride (PAC) and polyacrylamide (PAM) on sludge dewatering, aiming to unveil underlying mechanisms. Co-conditioning with 15 mg g−1 PAC and 1 mg g−1 PAM achieved optimal dewatering, reducing specific filtration resistance (SFR) of co-conditioned sludge to 4.38 × 1012 m−1kg−1, a mere 48.1% of raw sludge's SFR. Compared with the CST of raw sludge (36.45 s), sludge sample can be significantly reduced to 17.7 s. Characterization tests showed enhanced neutralization and agglomeration in co-conditioned sludge. Theoretical calculations revealed elimination of interaction energy barriers between sludge particles post co-conditioning, converting sludge surface from hydrophilic (3.03 mJ m−2) to hydrophobic (−46.20 mJ m−2), facilitating spontaneous agglomeration. Findings explain improved dewatering performance. Based on Flory-Huggins lattice theory, connection between polymer structure and SFR was established. Raw sludge formation triggered significant change in chemical potential, increasing bound water retention capacity and SFR. In contrast, co-conditioned sludge exhibited thinnest gel layer, reducing SFR and significantly improving dewatering. These findings represent a paradigm shift, shedding new light on fundamental thermodynamic mechanisms of sludge dewatering with different chemical conditioning.

Graphene-based diamond-shaped solar absorber using Fe–SiO2–Fe structure for UV to MIR region

Graphene based solar absorbers are gaining interest because of excellent optical properties of the material. We construct the perfect solar absorber in a diamond shape based on graphene. In this proposed design, the SiO2 substrate layer is sandwiched between the two Fe layers. The graphene layer is also inserted between Fe and SiO2 layers to improve the absorption of the design. The absorption rates can be studied in the four regions starting ultraviolet (UV) to mid-infrared region (MIR) between 0.2 and 3 μm. The total average solar absorption percentage from UV to MIR is 93.53%. The amount of solar absorption is more than 90% with a bandwidth range of 2800 nm. Also, the solar absorption reaches above 95% with a bandwidth of 900 nm and over 97% at an appropriate bandwidth of 930 nm. Solar absorption can be studied by the parameter variations by changing the width and thickness of a Fe ground layer, the thickness of SiO2 substrate and Fe resonator layers, and the chemical potential changes. Moreover, the solar absorption changes in TE and TM by varying the polarization from 0 to 80°. Furthermore, the electric field intensity can be found with the respective color plot in different ranges. Finally, we can compare our proposed diamond-shaped graphene-based solar absorber to the other published works.

Tunable THz dielectric resonator-graphene based dual port radiator with circular polarization and beam tilting features

In this article, a hybrid (dielectric resonator–graphene) MIMO antenna is presented and investigated at THz frequency. The unique properties associated with this antenna design are (i) CP waves are generated with the help of stair-shaped slot excitation; (ii) change in chemical potential of graphene creates the tunability in the proposed design structure; (iii) use of the metallic wall in between the antenna ports slants the far-field pattern by ± 30 deg, providing pattern diversity; and (iv) mirror image of the aperture introduces the concept of polarization diversity. The proposed antenna works between 4.65 and 5.71 THz with CP waves in between 5.25 and 5.5 THz. Polarization and pattern diversity help to improve the diversity performance of designed antenna. Good gain value and stable radiation pattern make the proposed antenna suitable for THz sensing applications.

Solubility of carbon dioxide in water: Some useful results for hydrate nucleation.

In this paper, the solubility of carbon dioxide (CO2) in water along the isobar of 400 bar is determined by computer simulations using the well-known TIP4P/Ice force field for water and the TraPPE model for CO2. In particular, the solubility of CO2 in water when in contact with the CO2 liquid phase and the solubility of CO2 in water when in contact with the hydrate have been determined. The solubility of CO2 in a liquid-liquid system decreases as the temperature increases. The solubility of CO2 in a hydrate-liquid system increases with temperature. The two curves intersect at a certain temperature that determines the dissociation temperature of the hydrate at 400bar (T3). We compare the predictions with T3 obtained using the direct coexistence technique in a previous work. The results of both methods agree, and we suggest 290(2)K as the value of T3 for this system using the same cutoff distance for dispersive interactions. We also propose a novel and alternative route to evaluate the change in chemical potential for the formation of hydrates along the isobar. The new approach is based on the use of the solubility curve of CO2 when the aqueous solution is in contact with the hydrate phase. It considers rigorously the non-ideality of the aqueous solution of CO2, providing reliable values for the driving force for nucleation of hydrates in good agreement with other thermodynamic routes used. It is shown that the driving force for hydrate nucleation at 400bar is larger for the methane hydrate than for the carbon dioxide hydrate when compared at the same supercooling. We have also analyzed and discussed the effect of the cutoff distance of dispersive interactions and the occupancy of CO2 on the driving force for nucleation of the hydrate.