Geometric shapes of the interface surface of bicomponent flows between two concentric rotating cylinders

In this paper, the shape problem of interface of bicomponent flows between two concentric rotating cylinders is investigated. With tensor analysis, the problem is reduced to an energy functional isoperimetric problem when neglecting the effects of the dissipative energy caused by viscosity. We derive the associated Euler-Lagrangian equation, which is a nonlinear elliptic boundary value problem of the second order. Moreover, by considering the effects of the dissipative energy, we propose another total energy functional to characterize the geometric shape of the interface, and obtain the corresponding Euler-Lagrangian equation, which is also a nonlinear elliptic boundary value problem of the second order. Thus, the problem of the geometric shape is converted into a nonlinear boundary value problem of the second order in both cases.

STUDIES ON THE CRIMP BEHAVIOR OF SIDE-BY-SIDE BICOMPONENT POLYAMIDE FIBERS

The supermolecular structure and mechanical properties as well as the crimp behavior of theside-by-side polyamide (PA 66-C710) fibers are studied by means of density gradient method,sonic measurement,X-ray,diffractometry,differential scanning calorimetry,crimp tester etc.fortheir as-spun fibers,drawn fibers,and boiling-water treated fibers.The effects of the processingand treatment conditions on the formation of the supermolecular structure and the crimp behaviorof the fibers are investigated and discussed in detail,also the crimp mechanism of the side-by-sidebicomponent fibers is proposed.From these results,it is shown that by adopting suitable spinningfinish,reasonable processing technology and optimal heat treatment conditions the side-by-sidebicomponent polyamide fibers with excellent crimp property,close to that of nylon texturizedstretch yarns,can be obtained.

Influence of Fiber Properties and Processing Parameters on Properties of Highloft Nonwoven Bonded by Bicomponent Polyester Fibers

Highloft nonwoven was produced by heat bonding of bicomponent polyester fibers. The effect of fiber properties and processing parameters on the mechanical properties of the nonwoven was investigated. The heat bonding processing parameters for the nonwoven were optimized. The results show that the range of processing temperature is wider while the shell melting point of the bicomponent fibers (Tm1) is lower. The best processing temperature is about 15℃ higher than Tm1 while the shell melting point (Tm1) is higher.

Studies on Melt Spinning of Sheath-Core Bicomponent Fibers: Fundamental Equations on the Dynamics of Melt Spinning

An attempt was made to numerically compute the temperature profile within the melt spinning of sheath core bicomponent fibers by deriving a set of simultaneous partial differential equations. The effects of acceleration, gravity, and air friction on the kinetics of the polymer were included and the upper-convected Maxwell model as the constitutive equation was adopted in this model.The sheath- core bicomponent fibers were partitioned intb a serial of circular cross section and it is assumed that each circular cross section has a temperature gradient while conducting the equation of energy balance. A mathematical model was developed to describe the melt spinning of sheath-core bicomponent fibers.

Study on the Process Technology of PA6/PET Bicomponent Fiber

PA6/PET bicomponent fiber at different spinning speedswere produced. Influences of cross blowing, spinning speed, PA6 and PET component ratio, drawing condition etc. on the mechanical properties, heat shrinkage,orientation and crystallization of the fiber were investigated. Also the rules among these influencing parameters were obtained. The splitting property of the fiber and its influence on the textile processing are discussed, which offers a base for the production of PA6/PET bicomponent fiber using splitting technology.

Intermolecular through-space charge transfer enabled by bicomponent assembly for ultrasensitive detection of synthetic cannabinoid JWH-018

Launching the intermolecular through-space charge transfer(TSCT)from a bicomponent assembly for photophysical property manipulation is of great significance in fluorescence probe design.Here,we demonstrate the elaborate control of droplet evaporation dynamics for intermolecular TSCT can facilitate the ultrasensitive detection of JWH-018,a representative synthetic cannabinoid.Driven by diverse intermolecular interactions,the probe,and JWH-018 assemble in a closely stacked manner to emit strong fluorescence at 477 nm,ascribing to the intermolecular TSCT at the S2 state.The strategy realizes an ultra-low limit of detection of 11 nmol/mL and great selectivity towards JWH-018.The practicability is further verified by constructing a sensing chip for JWH-018 aerosol detection,which facilitates the on-site drug abuser screening with the naked eye.Moreover,the proposed assembly-enabled TSCT is expected to find a variety of applications for optoelectronic materials design and photophysical mechanism-dominated molecular recognition.

Controllable large-scale processing of temperature regulating sheath-core fibers with high-enthalpy for thermal management

Temperature regulating fibers(TRF_(s)) with high enthalpy and high form stability are the key factors for thermal management. However, the enthalpies of most TRFsare not high, and the preparation methods are still at the laboratory scale. It remains a great challenge to use industrial spinning equipment to achieve continuous processing of TRF_(s) with excellent thermal and mechanical properties. Here, polyamide 6(PA6) based TRF_(s) with a sheath-core structure were prepared by bicomponent melt-spinning. The sheath-core TRF(TRF_(sc)) are composed of PA6 as sheath and functional PA6 as core, which are filled with the shape stable phase change materials(ssPCM),dendritic silica@polyethylene glycol(SiO_(2)@PEG). With the aid of the sheath structure, the filling content of SiO_(2)@PEG can reach 30 %, so that the enthalpy of the TRF_(s) can be as high as 21.3 J/g. The ultra-high enthalpy guarantees the temperature regulation ability during the alternating process of cooling and heating. In hot environment, the temperature regulation time is 6.59 min, and the temperature difference is 12.93℃. In addition, the mechanical strength of the prepared TRF_(sc) reaches 2.26 cN/dtex, which can fully meet its application in the field of thermal management textiles and devices to manage the temperature regulation of the human body or precision equipment, etc.

TRANSPORT OF BICOMPONENT CONTAMINANT IN FREE-SURFACE WETLAND FLOW

This paper presents a theoretical analysis of a pulsed bicomponent contaminant emission into a flee-surface wetland flow. The basic equations are for the bicomponent contaminant transport in the wetland flow under the combined action of advection, mass dispersion, and ecological reaction at the phase averaged scale. The effect of the ecological reaction is separated from the hydrodynamic effect via a set of widely used transforms. The analytical solution for the evolution of the depth-averaged concentration is rigorously derived, with a limiting case covering the known solution for the single component contaminant transport. It is found that the depth-averaged species concentration of the bicomponent contaminant can approach an equilibrium state determined by the distribution coefficient.

Entangled chimeras in nonlocally coupled bicomponent phase oscillators:From synchronous to asynchronous chimeras

Chimera states,a symmetry-breaking spatiotemporal pattern in nonlocally coupled identical dynamical units,have been identified in various systems and generalized to coupled nonidentical oscillators.It has been shown that strong heterogeneity in the frequencies of nonidentical oscillators might be harmful to chimera states.In this work,we consider a ring of nonlocally coupled bicomponent phase oscillators in which two types of oscillators are randomly distributed along the ring:some oscillators with natural.frequency w1 and others with w2.In this model,the heterogeneity in frequency is measured by frequency mismatch|w1-w2|between the oscillators in these two subpopulations.We report that the nonlocally coupled bicomponent phase oscillators allow for chimera states no matter how large the frequency mismatch is.The bicomponent oscillators are composed of two chimera states,one supported by oscillators with natural frequency wI and the other by oscillators with natural frequency w2.The two chimera states in two subpopulations are synchronized at weak frequency mismatch,in which the coberent oscillators in thern share similar mean phase velocity,and are desynchronized at large frequency mismatch,in which the coherent oscillators in different subpopulations have distinct mean phase velocities.The synchronization-desynchronization transition between chimera states in these two subpopulations is observed with the increase in the frequency mismatch.The observed phenomena are theoretically analyzed by passing to the continuum limit and using the Ott-Antonsen approach.

Spatial-temporal patterns of China＇s interprovincial migration, 1985-2010

Migration plays an increasing role in China＇s economy since mobility rose and economic restructuring has proceeded during the last three decades. Given the background of most studies focusing on migration in a particular period, there is a critical need to analyze the spatial-temporal patterns of migration. Using bicomponent trend mapping technique and interprovincial migration data during the periods 1985-1990, 1990-1995, 1995-2000, 2000- 2005, and 2005-2010 we analyze net-, in-, out-migration intensity, and their changes over time in this study. Strong spatial variations in migration intensity were found in China＇s interprovincial migration, and substantial increase in migration intensity was also detected in eastern China during 1985-2010. Eight key destinations are mostly located within the three rapidly growing economic zones of eastern China （Pearl River Delta, Yangtze River Delta and Beijing-Tianjin-Hebei Metropolitan Region）, and they are classified into three types： mature, emerging, and fluctuant origins, while most key origins are relatively undeveloped central and western provinces, which are exactly in accordance with China＇s economic development patterns. The results of bicomponent trend mapping indicate that, in a sense, the migration in the south was more active than the north over the last three decades. The result shows the new changing features of spatial-temporal patterns of China＇s interprovincial migration that Fan and Chen did not find out in their research. A series of social-economic changes including rural transformation, balanced regional development, and labor market changes should be paid more attention to explore China＇s future interprovincial migration.

Facile and Large-scale Fabrication of Self-crimping Elastic Fibers for Large Strain Sensors

Stretchable conductive fibers offer unparalleled advantages in the development of wearable strain sensors for smart textiles due to their excellent flexibility and weaveability.However,the practical applications of these fibers in wearable devices are hindered by either contradictory properties of conductive fibers(high stretchability versus high sensing stability),or lack of manufacturing scalability.Herein,we present a facile approach for highly stretchable self-crimping fiber strain sensors based on a polyether-ester(TPEE)elastomer matrix using a side-by-side bicomponent melt-spinning process involving two parallel but attached components with different shrinkage properties.The TPEE component serves as a highly elastic mechanical support layer within the bicomponent fibers,while the conductive component(E-TPEE)of carbon black(CB),multiwalled carbon nanotubes(MWCNTs)and TPEE works as a strain-sensitive layer.In addition to the intrinsic elasticity of the matrix,theTPEE/E-TPEE bicomponent fibers present an excellent form of elasticity due to self-crimping.The self-crimping elongation of the fibers can provide a large deformation,and after the crimp disappears,the intrinsic elastic deformation is responsible for monitoring the strain sensing.The reliable strain sensing range of theTPEE/E-TPEE composite fibers was 160%-270%and could be regulated by adjusting the crimp structure.More importantly,the TPEE/E-TPEE fibers had a diameter of 30-40 pm and tenacity of 40-50 MPa,showing the necessary practicality.This work introduces new possibilities for fiber strain sensors produced in standard industrial spinning machines.