Non-homogeneous Phase Research Articles

Experimental and theoretical study of the photo-Fenton and photoelectrochemical properties of Ni doped FeOCl

In this work, Ni doped FeOCl (Ni-FeOCl) was synthesized by simple calcination method and used as a non-homogeneous phase catalyst for the photo-Fenton degradation of tetracycline (TC). Photo-Fenton experiments showed that the degradation of TC by Ni-FeOCl-10 was 93.3 % in 60 min under neutral solution, room temperature and visible light conditions. The incorporation of Ni led to lattice defects on the surface of FeOCl, which was favorable for the separation efficiency of the photogenerated electron-hole pairs (in agreement with the density-functional theory calculations). In addition, the TC removal efficiency decreased from 93 % to 82 % in five consecutive cycles, showing good structural stability. Finally, a possible mechanism for the degradation of TC by Ni-FeOCl catalysts was proposed on the basis of free radical trapping experiments. This research contributes fresh perspectives to the development of photo-Fenton catalysts and the treatment of antibiotic organic wastewater.

Simultaneous enhanced antibiotic pollutants removal and sustained permeability of the membrane involving CoFe2O4/MoS2 catalyst initiated with simple H2O2 backwashing

Membranes for wastewater treatment should ideally exhibit sustainable high permeate production, enhanced pollutant removal, and intrinsic physical rejection. In this study, CoFe2O4/MoS2 serves as a non-homogeneous phase catalyst; it is combined with polyether sulfone membranes via liquid-induced phase separation to simultaneously sustain membrane permeability and enhance antibiotic pollutant degradation. The prepared catalytic membranes have higher pure water flux (329.34 L m−2 h−1) than pristine polyethersulfone membranes (219.03 L m−2 h−1), as well as higher mean pore size, porosity, and hydrophilicity. Under a moderate transmembrane pressure (0.05 MPa), tetracycline (TC) in synthetic and real wastewater was degraded by the optimal catalytic membrane by 72.7 % and 91.2 %, respectively. Owing to the generation of the reactive oxygen species (ROS) during the Fenton-like reaction process, the catalytic membrane could exclude the natural organics during the H2O2 backwash step and selectively promote fouling degradation in the membrane channel. The irreversible fouling ratio of the catalyzed membrane was significantly reduced, and the flux recovery rate increased by up to 91.6 %. A potential catalytic mechanism and TC degradation pathways were proposed. This study offers valuable insights for designing catalytic membranes with enhanced filtration performance.

Construction of recyclable Z-scheme MoS2/Fe/Bi2MoO6 heterojunctions for efficient photo-Fenton degradation performance

The non-homogeneous phase photo-Fenton technology exhibits significant promise for water treatment. Nevertheless, the development of photo-Fenton catalysts that are both extremely efficient and being reusable is still impeded. The hydrothermal technique was used to successfully synthesise a novel reusable Z-scheme oligomeric MoS2/Fe/Bi2MoO6 (OM/Fe/BMO) heterojunction in this study. The results indicate a significant enhancement in the photo-Fenton degradation effectiveness of antibiotic using the combination catalyst OM/Fe/BMO under visible light irradiation, achieving a 90.5 % removal rate within 120 min. This represents a 3-fold and 5.4-fold increase compared to OM and OBM, respectively. Moreover, the efficiency of photo-Fenton degradation for OM/Fe/BMO exceeded 85 % after all four cycles. The heterojunction was formed through the tightly connected interface between Fe-doped Bi2MoO6 and MoS2, which reduced the interfacial resistance and facilitated the separation and movement of light-generated charges. The heterojunction also enhances the Fe2+/Fe3+ cycle and promotes the decomposition of hydrogen peroxide, which leads to the generation of hydroxyl radicals that effectively destroy organic pollutants. The mechanism of the OM/Fe/BMO/Vis/H2O2 photo-Fenton degradation process has been elucidated through a series of characterizations and experiments. This study could inspire a water-treatment Z-scheme photo-Fenton catalyst.

Adsorption of ciprofloxacin on co-pyrolyzed biochar from fish scale and pine needle

The biochar (FS-PNBC) is prepared by pyrolyzing mixed biomass of fish scale and pine needle in varied proportions in a tube furnace. The biochar was characterized by a specific Brunauer-Emmett-Teller (BET) surface area analyzer, scanning electron microscope (SEM), Fourier infrared spectrometer (FTIR), and X-ray diffractometer (XRD). In a solution with an initial concentration of 60 mg/L, the adsorption of ciprofloxacin (CIP) by a 1:1 ratio of fish scale and pine needle co-pyrolyzed biochar (FS-PNBC1) reached 27.97 mg/g. The adsorption properties such as thermodynamics, kinetics, isothermal adsorption, and adsorption factors were investigated by batch experiments. The results indicate that FS-PNBC exhibits a significantly large specific surface area, abundant pore structure, and a high level of porosity. After approximately 180 min, adsorption equilibration was achieved in a pH=4 solution. The kinetic data was well-matched with a quasi-second-order model, suggesting that chemisorption plays a role in the adsorption process. Isothermal adsorption and thermodynamic results indicate that the adsorption of CIP by biochar is more consistent with the Freundlich model, which suggests multilayered non-homogeneous phase adsorption and an exothermic entropy-increasing reaction capable of proceeding spontaneously. FS-PNBC contains oxygen-containing functional groups, and through FTIR analysis, it was observed that hydrogen bonding, π-π bonding, and electrostatic interaction are closely linked to adsorption. This study demonstrates that biochar produced through the co-pyrolysis of fish scale and pine needle has the potential to serve as an efficacious adsorbent for extracting ciprofloxacin from wastewater.

Influence of Rotation Speed and Gas Content on the Transient Gas–Liquid Two-Phase Flow of an Electric Submersible Pump

In order to study the internal flow characteristics of the electric submersible pump (ESP) when the gas–liquid two-phase flow is conveyed by the variable frequency variable speed operation and the change of the imported gas content, the impeller of the Q10# ESP is taken as the research object, based on the Eulerian-Eulerian non-homogeneous phase. The flow model, the unsteady Reynolds time-averaged N-S equation, and the standard k-ε turbulence model are used for transient simulation calculations of the gas–liquid two-phase flow in the impeller of the ESP. Calculations show that with the rotation of the impeller, the gas phase is unevenly distributed in the flow channel. The gas phase is mainly concentrated on the inlet side of the flow channel near the front cover, and the gas phase exhibits periodic aggregation and diffusion in the flow channel. When the impeller speed increases, the period of periodic accumulation and diffusion of gas in the flow channel is shortened and the gas concentration in the impeller decreases, the overall flow velocity in the flow channel increases, and the pressure difference between the inlet and outlet increases. The pressure difference between the two sides of the blade is proportional to the speed of the impeller, and the fluctuation frequency of the blade surface also increases. As the gas content increases, the maximum concentration of gas phase in the flow channel increases. The area occupied by the high concentration of gas phase in the flow channel expands toward the blade’s working surface, and periodically accumulates, diffuses, and grows. The gas-liquid splitting area shrinks toward the front cover side and the pump. The internal pressure increases slightly, the main flow velocity increases, and the vortex action range increases.

Theoretical study on the potential environmental and ecological risk of 4-ethylphenol induced by hydroxyl radical

This study closely examines the environmental fate of 4-ethylphenol (4-EP), a significant byproduct of biomass combustion. We employed quantum chemical calculations to investigate the reaction mechanism, kinetics, and ecotoxicity of 4-EP initiated by OH radicals in various environments (aqueous, atmospheric liquid, atmospheric and inhomogeneous phases). Our findings highlight that solvent effects contribute to a higher OH-addition reaction branching ratio (Γadd) of 0.68 for 4-EP in an aqueous solution, compared to 0.26 in the gas-phase environment and 0.22 in the inhomogeneous environment at 298 K. We determined the rate constants for the liquid-phase, gas-phase, and nonhomogeneous phase to be 1.14 × 109 s−1 M−1, 3.09 × 109 s−1 M−1, and 6.19 × 1014 s−1 M−1, respectively. Notably, the adsorption of mineral particles considerably enhances the reaction rate of 4-EP with OH radicals. 4-ethylbenzene-1,2-diol, 4-hydroxycyclohexa-3,5-diene-1,2-dione, 1-ethyl-6-methyl-6H-benzo(c)chromene-4,9-diol, 5-ethyl-6'-(1-hydroxyethyl)-(1,1′-biphenyl)-2,3,3′-triol and 2-ethyl-4,6,9-trimethyl-6H-benzo(c) chromene are major products in both gas-phase and liquid-phase reactions, and (2Z, 4Z)-4-ethyl-6-oxohexa-2,4-dienoic acid is also one of the major products in gas-phase reactions. Toxicological predictions indicate that the ecotoxicity of 4-ethyl-6-methyl-6H-benzo(c)chromene-1,9-diol, 2-ethyl-6-methyl-6H-benzo(c)chromene-3,9-diol, and 2-ethyl-4,6,9-trimethyl-6H-benzo(c) chromene surpassed that of 4-EP. However, the toxicity of the reaction products is reduced in the presence of NOx. This investigation provides an exhaustive theoretical foundation for comprehending the degradation behavior of 4-EP and underscores the need to consider various environmental factors in assessing the potential risk of biomass combustion by products.

Dispersive estimates for nonhomogeneous radial phases: An application to weakly dispersive equations and water wave models

We study linear dispersive equations in dimension one and two for a class of radial nonhomogeneous phases. L1→L∞ type estimates, Strichartz estimates, local Kato smoothing and Morawetz type estimates are provided. We then apply our results to different water wave models.

Refinement effect of NbC particle additions on the microstructure of high-speed steel rolls

High-speed steel (HSS) rolls modified by different additions of NbC were prepared. The microstructure of as-cast and heat-treated NbC-modified HSS rolls were observed by means of optical microscope (OM), scanning electron microscope (SEM) and energy spectroscopy (EDS), combining with the result of dissolution behavior of NbC particles and interface energy of NbC/γ-Fe calculated by dissolution kinetic and first-principle, the effect of addition of NbC on microstructure of HSS rolls were discussed. Results show that NbC particles do not dissolve in melt under experimental conditions, and the NbC particles even coarsen due to the absorption of alloying elements during the subsequent cooling process. The NbC particles can act as the heterogeneous nucleuses of pre-eutectic austenite to refine the as-cast microstructure of HSS rolls. However, the added amount of NbC particles influence the distribution of NbC. With the increase of the amount of NbC particles, the distribution of NbC particles changes from austenite inter-dendrite region to dendrite. The NbC particles distributed in austenite inter-dendrite region can restrain the movement of solid-liquid interface, and refine the as-cast microstructure. The distribution of NbC within the austenite dendrites enhances the potential of NbC as a non-homogeneous phase nucleus, thereby further refining the microstructure.

A study on a class of generalized Schrödinger operators

In this paper, we consider the pointwise convergence for a class of generalized Schrödinger operators with suitable perturbations, and convergence rate along curves for a class of generalized Schrödinger operators with polynomial growth. We show that the almost sharp results of pointwise convergence remain valid for a class of generalized Schrödinger operators under small perturbations. As applications, we get the almost sharp pointwise convergence results for Boussinesq operator and Beam operator in R2. Moreover, the pointwise convergence results for a class of non-elliptic Schrödinger operators with finite-type perturbations are obtained. Furthermore, we build the relationship between smoothness of the functions and convergence rate along curves for a class of generalized Schrödinger operators with polynomial growth. We show that the convergence rate depends only on the growth condition of the phase function and regularity of the curve. Our result can be applied to a wide class of operators. In particular, pointwise convergence results along curves for a class of generalized Schrödinger operators with non-homogeneous phase functions are obtained and then the convergence rate is established.

Effects of magnetic field on freezing characters of carrot, potato and broccoli

In order to study the effects of magnetic field on the freezing characteristics of fruits and vegetables, carrot, potato and broccoli were frozen without and with a magnetic field of intensities 4.6 Gs, 9.2 Gs, 18 Gs and 36 Gs, while recording the temperature changes. The microstructure and temperature change of carrot during freezing were analyzed in detail. The results show that the magnetic field has effects on the freezing process of carrot strips, characterized by a reduction of the phase transition time and a characteristic diversity of the ice crystal formation zone. Crystallization characteristics are similar in the samples without and with a magnetic field of low intensities (4.6 Gs and 9.2 Gs), which show as a non-homogeneous phase transition process in the carrot sample, and the tissue changed showing a sunken, cell morphology variation and increased intercellular space. The freezing is almost homogeneous under a magnetic field of intensities 18 Gs and 36 Gs, then results in a slightly change of cell morphology. In addition, the effects of magnetic field on fruits and vegetables are varying with their species.

Degradation of Abiotic Orange II Dye and Biotic E. coli by Highly Porous SiC-AgCl/Ag0 Photocatalyst

An innovative procedure of producing highly porous SiC-AgCl/Ag0 photocatalyst were developed and tested for durability and degradability of abiotic material (azo dye, Orange II) and biotic material (bacterial, E. coli). Porous photocatalyst were made by 90% porosity silicon carbide in liquid nitrogen, coating with silver nitrate and precipitating out the non-homogeneous phase silver chloride on the surface by emerging the specimen in hydrochloride solution. SEM shows the needle-like nano sized crystal silver chloride were homogeneously crosslink on the silicon carbide backbone. Later on the specimen were heated at 200 °C for 8 h to enhance the adhesion of silver chloride and silicon carbide backbone. Through the XRD analysis under the condition of UV light irradiation, grey-black silver was generated on this porous material. Degradation of Orange II was performed under visible and UV light irradiation and the concentration degradation kinetics follow the first order reaction. Furthermore, the degradability of this photocatalyst which degrades Orange II could persist at least 4 cycles been used in our experiment with 96% degradability. Sterilization of Escherichia coli could be completed in 50 min and the degradation kinetics follows the first order reaction as well. The photocatalyst produced in this work not only reduced the cost of consuming too much silver nitrate, but increase the reliability and degradability of contaminant in the water.

Symmetry energy in neutron star matter

We investigate the structure attained by neutron star matter with proton to neutron ratios ranging from x=0.1 to 0.5, densities in the range of 0.02 fm−3 <ρ < 0.085 fm−3, and temperatures T<4 MeV. In particular we study the pasta shapes and the phase changes previously observed in nuclear matter, as well as the behavior of the symmetry energy. We corroborate the existence of homogeneous to non-homogeneous phase transitions, and the different values of the symmetry energy at different densities and temperatures.

Towards a holographic Bose-Hubbard model

We present a holographic construction of the large-N Bose-Hubbard model. The model is based on Maxwell fields coupled to charged scalar fields on the AdS2 hard wall. We realize the lobe-shaped phase structure of the Bose-Hubbard model and find that the model admits Mott insulator ground states in the limit of large Coulomb repulsion. In the Mott insulator phases, the bosons are localized on each site. At zero hopping we find that the transitions between Mott insulating phases with different fillings correspond to first order level-crossing phase transitions. At finite hopping we find a holographic phase transition between the Mott phase and a non-homogeneous phase. We then analyze the perturbations of fields around both the Mott insulator phase and inhomogeneous phase. We find almost zero modes in the non-homogeneous phase.

Effective mechanical properties of unidirectional composites in the presence of imperfect interface

In this paper, the equivalent inclusion method is implemented to estimate the effective mechanical properties of unidirectional composites in the presence of an imperfect interface. For this purpose, a representative volume element containing three constituents, a matrix, and interface layer, and a fiber component, is considered. A periodic eigenstrain defined in terms of Fourier series is then employed to homogenize non-dilute multi-phase composites. In order to take into account the interphase imperfection effects on mechanical properties of composites, a stiffness parameter in terms of a matrix and interphase elastic modulus is introduced. Consistency conditions are also modified accordingly in such a way that only the part of the fiber lateral stiffness is to be effective in estimating the equivalent composite mechanical properties. Employing the modified consistency equations together with the energy equivalence relation leads to a set of linear equations that are consequently used to estimate the average values of eigenstrain in non-homogeneous phases. It is shown that for composites with both soft and hard reinforcements, largest stiffness parameter that indicates complete fiber–matrix interfacial debonding causes the same equivalent lateral properties.

Ultra-Dense Hydrogen H(−1) as the Cause of Instabilities in Laser Compression-Based Nuclear Fusion

Ultra-dense hydrogen H(−1) is a quantum material and the first material which is superfluid and superconductive at room temperature. This has been shown in detail for the deuterium form D(−1). With its experimentally determined H–H bond distance of normally 2.3 ± 0.1 pm, it is up to a factor of 105 denser than hydrogen ice composed of H2 molecules. Its existence means that when hydrogen is compressed to high temperature and density, as in laser-induced nuclear inertial-confinement fusion (ICF), sudden localized spontaneous transitions to H(−1) will give spots in the material where pressure falls strongly. Such pressure drops give a non-homogeneous phase which will not ignite smoothly. The energy released by the rapid transition to H(−1) will further cause non-isotropic motion of the target material. We here propose that the instability problems which plague ICF can be circumvented by using ultra-dense hydrogen H(−1) directly as the fusion fuel.

Phase transformation and subsurface damage in 3Y-TZP after sandblasting

ObjectiveThe goal of this work is to investigate t–m phase transformation, and subsurface damage in 3Y-TZP after sandblasting. MethodsCommercial grade 3Y-TZP powder was conventionally sintered and fully dense specimens were obtained. Specimens were sandblasted using different particle sizes (110 and 250μm) and pressures (2 and 4bar) for 10s. Phase transformation was measured on the surface and in the cross-section using X-ray diffraction and micro Raman spectroscopy, respectively. Subsurface damage was investigated on cross-sections using SEM and in shallow cross-sections machined by focused ion beam. ResultsSandblasting induced monoclinic volume fraction is in the range of 12–15% on the surface. In the cross-section, a non-homogeneous phase transformation gradient is found up to the depth of 12±1μm. The subsurface damage observed was plastic deformation in grains with the presence of martensite plates, and this effect is found to be larger in specimens sandblasted with large particles. SignificanceThe extent of subsurface tetragonal–monoclinic transformation and damage induced by sandblasting are reported for different sandblasting conditions. This knowledge is critical in order to understand the effect of sandblasting on mechanical properties of zirconia used to fabricate dental crowns and frameworks.

Dynamical properties of nuclear and stellar matter and the symmetry energy

The effects of density dependence of the symmetry energy on the collective modes and dynamical instabilities of cold and warm nuclear and stellar matter are studied in the framework of relativistic mean-field hadron models. The existence of the collective isovector and possibly an isoscalar collective mode above saturation density is discussed. It is shown that soft equations of state do not allow for a high density isoscalar collective mode, however, if the symmetry energy is hard enough an isovector mode will not disappear at high densities. The crust-core transition density and pressure are obtained as a function of temperature for $\beta$-equilibrium matter with and without neutrino trapping. An estimation of the size of the clusters formed in the non-homogeneous phase as well as the corresponding growth rates and distillation effect is made. It is shown that cluster sizes increase with temperature, that the distillation effect close to the inner edge of the crust-core transition is very sensitive to the symmetry energy, and that, within a dynamical instability calculation, the pasta phase exists in warm compact stars up to 10 - 12 MeV.

Dynamical instabilities of warmnpematter:δmeson effects

The effects of $\ensuremath{\delta}$ mesons on the dynamical instabilities of cold and warm nuclear and stellar matter at subsaturation densities are studied in the framework of relativistic mean-field hadron models $(\mathrm{NL}3$, $\mathrm{NL}\ensuremath{\rho}$, and $\mathrm{NL}\ensuremath{\rho}\ensuremath{\delta})$ with the inclusion of the electromagnetic field. The distillation effect and the spinodals for all the models considered are discussed. The crust-core transition density and pressure are obtained as a function of temperature for $\ensuremath{\beta}$-equilibrium matter with and without neutrino trapping. An estimation of the size of the clusters formed in the nonhomogeneous phase and the corresponding growth rates are made. It is shown that cluster sizes increase with temperature. The effects of the $\ensuremath{\delta}$ meson on the instability region are larger for low temperatures, very asymmetric matter, and densities close to the spinodal surface. It increases the distillation effect above $~0.4{\ensuremath{\rho}}_{0}$ and has the opposite effect below that density.

Continuum Landau Model for Biaxial Nematic Liquid Crystals

We present a phenomenological theory for the homogeneous phases of nematic liquid crystals constituted by biaxial D 2h -symmetric molecules. We propose a general polynomial free-energy in two macroscopic order tensors that reproduces the mean-field phase diagram confirmed by Monte Carlo simulations [De Matteis et al., Phys. Rev. E 72 , 041706, (2005)] and recently recognized to be universal [Bisi et al., Phys. Rev. E 73 , 051709, (2006)] for dispersion forces molecular pair potentials enjoying the D 2h symmetry. The requirement that the phenomenological theory comply uniquely with this phase diagram reduces considerably the admissible phenomenological coefficients, both in their number and in the ranges where they can vary. We also consider a generalization of the polynomial theory in order to describe non-homogeneous phases in confined geometries of liquid crystals.

Study on the Reaction Kinetics of Ultrasonic Radiation Non-homogeneous Phase Chitin Deacetylation

Under the condition of ultrasonic radiation, in this article, we studied the reaction kinetics of non-homogeneous phasechitin deacetylation. The results indicated that the deacetylation degree of chitin was obviously enhanced under thecondition of ultrasonic radiation, and the reaction process accorded with pseudo-first order kinetics relationship, and thereaction control is diffusion control, and the surface activation energy was E=23.45kJ/mol.