Quasistable bright dissipative holographic solitons in photorefractive two-wave mixing system

The dynamical evolution of both signal and pump beams are traced by numerically solving the coupled-wave equation for a photorefractive two-wave mixing system. The direct simulations show that, when the intensity ratio of the pump beam to the signal beam is large enough, the pump beam presents a common decaying behaviour without modulational instability （MI）, while the signal beam can evolve into a quasistable spatial soliton within a regime in which the pump beam is depleted slightly. The larger the ratio is, the longer the regime is. Such quasistable solitons can overcome the initial perturbations and numerical noises in the course of propagation, perform several cycles of slow oscillation in intensity and width, and persist over tens of diffraction lengths. From physical viewpoints, these solitons actually exist as completely rigorous physical objects. If the ratio is quite small, the pump beam is apt to show MI, during which the signal beam experiences strong expansion and shrinking in width and a drastic oscillation in intensity, or completely breaks up. The simulations using actual experimental parameters demonstrate that the observation of an effectively stable soliton is quite possible in the proposed system.

Evolution and stability of spatial solitons in a photorefractive two-wave mixing system

The dynamical evolution and stability of bright dissipative holographic solitons in biased photorefractive materials in which the self-trapping beam obtains a gain from the pump beam via two-wave mixing has been investigated numerically. Results show that these solitons are stable relative to small perturbations. Adjusting some system parameters, such as the bias field and the angle between beams, can easily control the generation of such solitons. Potential applications in optical switches or repeaters are discussed.

Rigidity in Subclasses of Transitive and Mixing Systems

We will present some restrictions for a rigidity sequence of a nontrivial topological dynamical system. For instance, any finite linear combination of a rigidity sequence by integers has upper Banach density zero. However, there are rigidity sequences for some uniformly rigid systems whose reciprocal sums are infinite. We also show that if F is a family of subsets of natural numbers whose dual F* is filter, then a minimal F*-mixing system does not have F+-rigid factor for F∈F.

Effectively modulating spatial vortex four-wave mixing in a diamond atomic system

Due to the spatial characteristics of orbital angular momentum,vortex fields can be applied in the fields of quantum storage and quantum information.We study the realization of spatially modulated vortex fields based on four-wave mixing in a four-level atomic system with a diamond structure.The intensity and spiral phase of the vortex field are effectively transferred to the generated four-wave mixing field.By changing the detuning of the probe field,the phase and intensity of the generated vertex four-wave mixing field can be changed.When the probe field takes a large detuning value,the spatial distribution of the intensity and phase of the vertex four-wave mixing field can be effectively tuned by adjusting the Rabi frequency or detuning value of the coupled field.At the same time,we also provide a detailed explanation based on the dispersion relationship,and the results agree well with our simulation results.

O,H,and Sr isotope evidence for origin and mixing processes of the Gudui geothermal system,Himalayas,China

Tho Gudui geothermal field records the highest temperature at equivalent borehole depths among the lainland hydrothermal systems in China's Mainland.Located about 150 km southeast of Lhasa City,the capital of Tibet,the Gudui geothermal field belongs to the Sangri-Cuona rift belt,also known as the Sangri-Cuona geothermal belt,and is representative of the non-volcanic geothermal systems in the Himalayas.In this study,oxygen-18 and deuterium isotope compositions as well as 87Sr/86Sr ratios of water samples collected from the Gudui geothermal field were characterized to understand the origin and mixing processes of the geothermal fluids at Gudui.Hydrogen and oxygen isotope plots show both,deep and shallow reservoirs in the Gudui geothermal field.Deep geothermal fluids are the mixing product of magmatic and infiltrating snow-melt water.Calculations show that the magma fluid component of the deep geothermal fluids account for about 21.10%-24.04%;magma fluids lay also be a contributing source of lithium.The linear relationship of the 87Sr/86Sr isotopic ratio versus the 1/Sr plot indicates that shallow geothermal fluids form from the mixing of deep geothermal fluids with cold groundwater.Using a binary mixing model with deep geothermal fluid and cold groundwater as two end-members,the nixing ratios of the latter in most surface hot springs samples were calculated to be between 5% and 10%.Combined with basic geological characteristics,hydrogen and oxygen isotope characteristics,strontium concentration,87Sr/(86)Sr ratios,and the binary mixing model,we infer the 6 th-Class Reservoirs Evolution Conceptual Model(6-CRECM) for the Gudui geothermal system.This model represents an idealized summary of the characteristics of the Gudui geothermal field based on our comprehensive understanding of the origin and mixing processes of the geothermal fluid in Gudui.This study may aid in identifying the geothermal and geochemical origin of the Gudui high-temperature hydrothermal systems in remote Tibet of China,whose potential for geothermal development and utilization is enormous and untapped.

Systematic review of mixing technology for recycling waste tailings as cemented paste backfill in mines in China

The development of industry is inseparable from the support of mining.However,mining processes consume a large amount of energy,and increased tailing emissions can have a significant impact on the environment.In the past few decades,the mining industry developed many technologies that are related to mineral energy management,of which cemented paste backfill(CPB)is one of the representative technologies.CPB has been successfully applied to mine ground control and tailings management.In CPB technology,the mixing process is the key to achieving materials with good final quality and controlled properties.However,in the preparation process,the mixed homogeneity of the CPB is difficult to achieve because of fine tailings,high solid volume fraction,and high viscosity.Most research focused on the effect of mixing ingredients on CPB properties rather than on the preparation process of the CPB.Therefore,improving the performance and reducing the production cost of CPB by optimizing the mixing process are important.This review summarizes the current studies on the mixing technology of CPB and its application status in China.Then,it compares the advantages and disadvantages of multiple mixing equipment and discusses the latest results and research hotspots in paste preparation.Finally,it concludes the challenges and development trends of mixing technology on the basis of the relevant application cases in China to promoting cement-based material mixing technology development.

Rheological properties of a multiscale granular system during mixing of cemented paste backfill:A review

The technology of cemented paste backfill(CPB)is an effective method for green mining.In CPB,mixing is a vital process aiming to prepare a paste that meets the non-stratification,non-segregation,and non-bleeding requirements.As a multiscale granular system,homogenization is one of the challenges in the paste-mixing process.Due to the high shearing,high concentration,and multiscale characteristics,paste exhibits complex rheological properties in the mixing process.An overview of the mesomechanics and structural evolution is presented in this review.The effects of various influencing factors on the paste's rheological properties were investigated,and the rheological models of the paste were outlined from the macroscopic and mesoscopic levels.The results show that the mechanical effects and structural evolution are the fundamental factors affecting the rheological properties of the paste.Existing problems and future development trends are presented to change the practice where the CPB process comes first and the theory lags.

Stochastic resonance in an under-damped bistable system driven by harmonic mixing signal

Stochastic resonance（SR） is studied in an under-damped bistable system driven by the harmonic mixing signal and Gaussian white noise. Using the linear response theory（LRT）, the expressions of the spectral amplification at fundamental and higher-order harmonic are obtained. The effects of damping coefficient, noise intensity, signal amplitude, and frequency on spectral amplifications are explored. Meanwhile, the power spectral density（PSD） and signal-to-noise ratio（SNR） are calculated to quantify SR and verify the theoretical results. The SNRs at the first and second harmonics exhibit a minimum first and a maximum later with increasing noise intensity. That is, both of the noise-induced suppression and resonance can be observed by choosing proper system parameters. Especially, when the ratio of the second harmonic amplitude to the fundamental one takes a large value, the SNR at the fundamental harmonic is a monotonic function of noise intensity and the SR phenomenon disappears.

Geochemical assessment, mixing behavior and environmental impact of thermal waters in the Guelma geothermal system,Algeria

A study of thirteen geothermal springs located in the geothermal field of Guelma,northeastern Algeria,was conducted.Samples were collected during the period between January 2014 and February 2016.Geochemical processes responsible for the chemical composition of thermal and mineralized water were evaluated.The hydrochemical analysis shows that the thermal waters are characterized by the presence of two different chemical facies,the first type SO4-Ca in the east,west and south of Guelma,the second type HCO3-Ca in the south.This analysis also attributed to sodium,chlorides,and sulfates to an evaporitic terrigenous origin by the molar ratio Sr2+/Ca2+.The thermal spring waters from Guelma geothermal system have a meteoric origin,and all samples are immature with strong mixing between hot and shallow waters with 19-38.5%rate of mixing.The silica geothermometer shows that these thermal waters have a temperature varying from 84 to 122℃and that the water came from a depth of 2100-3000 m through a fault system that limits the pullapart basin of Guelma.Potential environmental effluent from thermal spas could pollute in both the irrigation and drinking waters,and which imposes danger on the health of the inhabitants of the region.

Computational Analysis of Mixing Guide Vane Effects on Performance of the Supersonic Ejector-Diffuser System

The flow field in the ejector-diffuser system and its optimal operation condition are hardly complicated due to the complicated turbulent mixing, compressibility effects and even flow unsteadiness which are generated inside the ejector- diffuser system. This paper aims at the improvement in ejector-diffuser system by focusing attention on entrainment ratio and pressure recovery. Several mixing guide vanes were installed at the inlet of the secondary stream for the purpose of the performance improvement of the ejector system. A Computational Fluid Dynamics (CFD) method based on Fluent has been applied to simulate the supersonic flows and shock waves inside the ejector. A finite volume scheme and density-based solver with coupled scheme were applied in the computational process. Standard k-ω turbulent model, implicit formulations were used considering the accuracy and stability. Previous experimental results showed that more flow vortexes were generated and more vertical flow was introduced into the stream under a mixing guide vane influence. Besides these effects on the secondary stream, the mixing guide vane effects on the shock system of the primary stream were also investigated in this paper. Optimal analysis results of the mixing guide vane effects were also carried out in detail in terms of the positions, lengths and numbers to achieve the best operation condition. The comparison of ejector performance with and without the mixing guide vane was obtained. The ejector-diffuser system performance is discussed in terms of the entrainment ratio, pressure recovery as well as total pressure loss.

Analysis of Radio over Fiber system for mitigating four-wave mixing effect

In this paper,an efficient 8-channel 32Gbps RoF(Radio over Fiber)system incorporating Bessel Filter(8/32 RoFBF)has been demonstrated to reduce the impact of non-linear transmission effects,specifically Four-Wave Mixing(FWM).The simulation results indicate that the proposed 8/32 RoF-BF system provides an optimum result w.r.t.channel spacing(75 GHz),input source power(0 dBm)and number of input channels(8).In comparison with the existing RoF system,the proposed 8/32 RoF-BF system has been validated analytically and it is found that the performance of the proposed system is in close proximity particularly in FWM sideband power reduction of the order of 4 dBm for the 8-channel 32Gbps RoF system.

Study on mixing and segregation behaviors in particulate fluidized bed system for mineral processing

In order to identify the mixing and segregation behaviors in a mineral processing operation, present study aimed on the hydrodynamics of solid–liquid fluidization. The study was carried out in a fluidization column with tapings at different height of the bed to collect the sample. The binary particles considered in this study are hematite(4800 kg/m3) and quartz(2600 kg/m3) at different size fractions in the range of average size 87×10^(-6)m to 400×10^(-6)m. It is observed that for various binary mixtures, both quartz and hematite particles share the equal composition by mass(50%) at a particular height of fluidized bed, referred as ‘‘locus point'' of mixing. Study indicates that the mixing zone volume will increase for a continuous fluidized bed plant operation. It is observed that the number of locus points varies from 1 to 3 signifying their dependency on the size ratios of binary mixture. Whenever, the difference in terminal velocity between quartz and hematite particles approaches to zero, mixing is enhanced.Further, the present study is extended to find the segregation index for the different size ratios of quartz and hematite particles. It is evident that depending on the size ratios, various regions such as complete segregation, partial mixing and complete mixing can be observed.

A strategy for strengthening chaotic mixing of dual shaft eccentric mixers by changing non-Newtonian fluids kinetic energy distribution

Efficiently modulating the velocity distribution and flow pattern of non-Newtonian fluids is a critical challenge in the context of dual shaft eccentric mixers for process intensification,posing a significant barrier for the existing technologies.Accordingly,this work reports a convenient strategy that changes the kinetic energy to controllably regulate the flow patterns from radial flow to axial flow.Results showed that the desired velocity distribution and flow patterns could be effectively obtained by varying the number and structure of baffles to change kinetic energy,and a more uniform velocity distribution,which could not be reached normally in standard baffle dual shaft mixers,was easily obtained.Furthermore,a comparative analysis of velocity and shear rate distributions is employed to elucidate the mechanism behind the generation of flow patterns in various dual-shaft eccentric mixers.Importantly,there is little difference in the power number of the laminar flow at the same Reynolds number,meaning that the baffle type has no effect on the power consumption,while the power number of both unbaffle and U-shaped baffle mixing systems decreases compared with the standard baffle mixing system in the transition flow.Finally,at the same rotational condition,the dimensionless mixing time of the U-shaped baffle mixing system is 15.3%and 7.9%shorter than that of the standard baffle and the unbaffle mixing system,respectively,which shows the advantage of the U-shaped baffle in stirring rate.

Experimental study on secondary air mixing along the bed height in a circulating fluidized bed with a multitracer-gas method

A multitracer-gas method was proposed to study the secondary air(SA)mixing along the bed height in a circulating fluidized bed(CFB)using carbon monoxide(CO),oxygen(O_(2)),and carbon dioxide(CO_(2))as tracer gases.Experiments were carried out on a cold CFB test rig with a cross-section of 0.42 m×0.73 m and a height of 5.50 m.The effects of superficial velocity,SA ratio,bed inventory,and particle diameter on the SA mixing were investigated.The results indicate that there are some differences in the measurement results obtained using different tracer gases,wherein the deviation between CO and CO_(2) ranges from 42%to 66%and that between O_(2) and CO_(2) ranges from 45%to 71%in the lower part of the fluidized bed.However,these differences became less pronounced as the bed height increased.Besides,the high solid concentration and fine particle diameter in the CFB may weaken the difference.The measurement results of different tracer gases show the same trends under the variation of operating parameters.Increasing superficial velocity and SA ratio and decreasing particle diameter result in better mixing of the SA.The effect of bed inventory on SA mixing is not monotonic.

HYDRODYNAMICS AND AXIAL MIXING OF LIQUIDSOLID SYSTEM IN OPEN TURBINE ROTATING DISC CONTACTOR

The open turbine rotating disc contactor (OTRDC) has been installed simply by adding three narrow strips to the lower surface of each rotating disc in the rotating disc contactor (RDC), so it can be used for the system with high solid particle content. Hydrodynamics and axial mixing have been investigated in a 0.152m diameter OTRDC of different compartment height for the system of tap water and quartz particles. A model has been developed to describe the flow of liquid and solid phases. The solid phase holdup can be calculated satisfactorily according to the model equations. Axial mixing data have been treated by the backflow model and the correlations for predicting backflow ratios of liquid and solid phases in OTRDC have been presented.

Jet Noise Reduction of Double-Mixing Exhaust System

A jet noise reduction technique by using the external chevron nozzle with lobed mixer in the double-mixing exhaust system is investigated under cold conditions.The computations of jet field and the experiments of noise field are conducted with scaled model of high-bypass-ratio turbofan engine mixing exhaust system composed of external chevron nozzle with lobed mixer.The computational results indicate that comparing with the baseline nozzle with lobed mixer,the external chevron nozzle with lobed mixer increases mixing of jet and ambient air near the nozzle exit.The experimental results show that the external chevron nozzle with lobed mixer has better jet noise reduction at low frequencies,and this reduction rises with the increase of chevron bend angle.The experimental results also show that the external chevron nozzle with lobed mixer has sound pressure level(SPL)increase which is not obvious at high frequencies.With chevron bend angle increasing,SPL has relatively marked increase at 60°(directivity angle measured from upstream jet axis)and little fluctuations at 90°and 150°.The external chevron nozzle with lobed mixer has overall sound pressure level(OASPL)reduction in varying degrees at 60°and 150°,but it has little OASPL increase at 90°.

Tuning Li/Ni mixing by reactive coating to boost the stability of cobalt-free Ni-rich cathode

Cobalt-free cathode materials are attractive for their high capacity and low cost,yet they still encounter issues with structural and surface instability.AlPO_(4),in particular,has garnered attention as an effective stabilizer for bulk and surface.However,the impact of interfacial reactions and elemental interdiffusion between AlPO_(4) and LiNi_(0.95)Mn_(0.05)O_(2) upon sintering on the bulk and surface remains elusive.In this study,we demonstrate that during the heat treatment process,AlPO_(4) decomposes,resulting in Al doping into the bulk of the cathode through elemental interdiffusion.Simultaneously,PO_(4)^(3-)reacts with the surface Li of material to form a Li_3PO_(4) coating,inducing lithium deficiency,thereby increasing Li/Ni mixing.The suitable Li/Ni mixing,previously overlooked in AlPO_(4) modification,plays a pivotal role in stabilizing the bulk and surface,exceeding the synergy of Al doping and Li_3PO_(4) coating.The presence of Ni^(2+)ions in the lithium layers contributes to the stabilization of the delithiated structure via a structural pillar effect.Moreover,suitable Li/Ni mixing can stabilize the lattice oxygen and electrode-electrolyte interface by increasing oxygen removal energy and reducing the overlap between the Ni^(3+/4+)e_g and O^(2-)2p orbitals.These findings offer new perspectives for the design of stable cobalt-free cathode materials.

Influence of alkali mixed effect on the mixing enthalpy in 0.75B_2O_3-0.25[xNa_2O-(1-x)K_2O]glass system

The mixed alkali effect was investigated in the glass system 0.75B2O3-0.25[xNa2O-（1 -x）K20] through thermodynamic properties. The calorimetric measurements were performed in HF solution calorimetry at 298 K. The mixing enthalpy values show non-linear behaviour upon substitution of one alkali ion by another. This thermodynamic non-ideality is caused by the slight variations of distance between metallic cations, the macromolecular structure being unchanged. It can be explained, at least qualitatively, using electrolyte theory based on the Coulombic interactions of charged species originally developed by Debye and Hückel.

Effect of Dissolved Cadmium Chloride and Ammonium Chloride Salts on the Enthalpy of Mixing of the Methanol＋Benzene System at 303.15 K

The effect of two dissolved inorganic salts,cadmium chloride CdCl2 and ammonium chloride NH4Cl,on the excess enthalpy of mixing(HE) of the binary system methanol + benzene measured at 303.15 K using an iso-thermal displacement calorimeter with vapor space is investigated in the present work. Compared to the salt-free system,a decreasing trend in the endothermicity of HE values is significant with the addition of CdCl2 salt but the decrease in the HE values is insignificantly smaller with the addition of NH4Cl salt. The experimental values of the enthalpy of mixing are fitted into a Redlich-Kister equation and the deviations in the values and the parameters are reported. The importance of the solute-solvent interactions and the solvent-solvent interactions are demonstrated from the increasing excess enthalpy of mixing values in the positive direction with the increase of salt concentration.

Computational and experimental investigation of laminar flow mixing system in a pitched-blade turbine stirred tank

The flow distribution and mixing performance of the laminar flow in the PBT impeller-stirred tank were investigated in this study.The variation along with mixing time of the flow distribution and concentration at the selected positions was visualized by means of the CFD and experiment methods.The CFD simulations results had a good agreement with the experimental results.In order to minish the Segregated Regions,the PBT impeller was optimally designed by means of orthogonal factorial experiment with selecting theθ99 mixing time as evaluation criteria.With the aim to increase the mixing efficiency,the optimal design results were obtained with the geometrical parameters of impeller diameter of 0.084 m,discharge angle of 45º,blade width of 0.018 m,and clearance of 0.05 m,and the mixing time of the optimal impeller-stirred flow was about 180 s,so this optimal design PBT impeller is more proper for the agricultural industries.