Dynamic thermo-mechanical responses of road-soft ground system under vehicle load and daily temperature variation

A complete road-soft ground model is established in this paper to study the dynamic responses caused by vehicle loads and/or daily temperature variation.A dynamic thermo-elastic model is applied to capturing the behavior of the rigid pavement,the base course,and the subgrade,while the soft ground is characterized using a dynamic thermo-poroelastic model.Solutions to the road-soft ground system are derived in the Laplace-Hankel transform domain.The time domain solutions are obtained using an integration approach.The temperature,thermal stress,pore water pressure,and displacement responses caused by the vehicle load and the daily temperature variation are presented.Results show that obvious temperature change mainly exists within 0.3 m of the road when subjected to the daily temperature variation,whereas the stress responses can still be found in deeper places because of the thermal swelling/shrinkage deformation within the upper road structures.Moreover,it is important to consider the coupling effects of the vehicle load and the daily temperature variation when calculating the dynamic responses inside the road-soft ground system.

Effect of Initial Microstructure Prior to Extrusion on the Microstructure and Mechanical Properties of Extruded AZ80 Alloy with a Low Temperature and a Low Ratio

Magnesium(Mg)alloys are the lightest metal structural material for engineering applications and therefore have a wide market of applications.However,compared to steel and aluminum alloys,Mg alloys have lower mechanical properties,which greatly limits their application.Extrusion is one of the most important processing methods for Mg and its alloys.However,the effect of such a heterogeneous microstructure achieved at low temperatures on the mechanical properties is lacking investigation.In this work,commercial AZ80 alloys with different initial microstructures(as-cast and as-homogenized)were selected and extruded at a low extrusion temperature of 220℃and a low extrusion ratio of 4.The microstructure and mechanical properties of the two extruded AZ80 alloys were investigated.The results show that homogenized-extruded(HE)sample exhibits higher strength than the cast-extruded(CE)sample,which is mainly attributed to the high number density of fine dynamic precipitates and the high fraction of recrystallized ultrafine grains.Compared to the coarse compounds existing in CE sample,the fine dynamical precipitates of Mg17(Al,Zn)12form in the HE sample can effectively promote the dynamical recrystallization during extrusion,while they exhibit a similar effect on the size and orientation of the recrystallized grains.These results can facilitate the designing of high-strength wrought magnesium alloys by rational microstructure construction.

Application of CFD and FEA Coupling to Predict Structural Dynamic Responses of A Trimaran in Uni-and Bi-Directional Waves

To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing from the existing coupled CFD-FEA method for monohull ships in head waves,the presented method equates the mass and stiffness of the whole ship to the hull shell so that any transverse and longitudinal section stress of the hull in oblique waves can be obtained.Firstly,verification study and sensitivity analysis are carried out by comparing the trimaran motions using different mesh sizes and time step schemes.Discussion on the wave elevation of uni-and bi-directional waves is also carried out.Then a comprehensive analysis on the structural responses of the trimaran in different uni-directional regular wave and bi-directional cross sea conditions is carried out,respectively.Finally,the differences in structural response characteristics of trimaran in different wave fields are studied.The results show that the present method can reduce the computational burden of the two-way fluid-structure interaction simulations.

Anisotropic strength,deformation and failure of gneiss granite under high stress and temperature coupled true triaxial compression

The anisotropic mechanical behavior of rocks under high-stress and high-temperature coupled conditions is crucial for analyzing the stability of surrounding rocks in deep underground engineering.This paper is devoted to studying the anisotropic strength,deformation and failure behavior of gneiss granite from the deep boreholes of a railway tunnel that suffers from high tectonic stress and ground temperature in the eastern tectonic knot in the Tibet Plateau.High-temperature true triaxial compression tests are performed on the samples using a self-developed testing device with five different loading directions and three temperature values that are representative of the geological conditions of the deep underground tunnels in the region.Effect of temperature and loading direction on the strength,elastic modulus,Poisson’s ratio,and failure mode are analyzed.The method for quantitative identification of anisotropic failure is also proposed.The anisotropic mechanical behaviors of the gneiss granite are very sensitive to the changes in loading direction and temperature under true triaxial compression,and the high temperature seems to weaken the inherent anisotropy and stress-induced deformation anisotropy.The strength and deformation show obvious thermal degradation at 200℃due to the weakening of friction between failure surfaces and the transition of the failure pattern in rock grains.In the range of 25℃ 200℃,the failure is mainly governed by the loading direction due to the inherent anisotropy.This study is helpful to the in-depth understanding of the thermal-mechanical behavior of anisotropic rocks in deep underground projects.

An Original Didactic about Standard Model (Geometric Model of Particle: The Quarks)

This work shows a didactic model representative of the quarks described in the Standard Model (SM). In the model, particles are represented by structures corresponding to geometric shapes of coupled quantum oscillators (GMP). From these didactic hypotheses emerges an in-depth phenomenology of particles (quarks) fully compatible with that of SM, showing, besides, that the number of possible quarks is six.

Correlation Analysis of Wind Turbine Temperature Rise and Exergy Efficiency Based on Field-Path Coupling

To solve the problems of large losses and low productivity of permanent magnet synchronous generators used in wind power systems,the field-circuit coupling method is used to accurately solve the electromagnetic field and temperature field of the generator.The loss distribution of the motor is accurately obtained by considering the influence of external circuit characteristics on its internal physical field.By mapping the losses to the corresponding part of the three-dimensional finite element model of the motor,the temperature field is solved,and the global temperature distribution of the generator,considering the influence of end windings,is obtained.By changing the air gap length,permanent magnet thickness,and winding conductivity,the relationship between the loss,temperature rise,and exergy efficiency can be obtained.By optimizing the air gap length,permanent magnet thickness,and winding conductivity,the best configuration and material properties can improve the efficiency of the motor by up to 4%.

On the Fine Structure and the Other Coupling Constants at the Planck Scale

It is shown that the fine structure constant at Planck times tends to one as well as those of the weak and strong interactions. This results by constraining them at the Planck force. That seems to provide interesting new results which confirm that at the beginning of space time (Planck scale) all fundamental forces converge to the same unit value.

Coupling Effects on Gold Mineralization of Deep and Shallow Structures in the Northwestern Jiaodong Peninsula, Eastern China

For understanding the possible deep-seated processes and geodynamic constrains on gold mineralization, comprehensive physicochemical and geochemical studies of gold mineralization have been undertaken within the paleo-lithosphere framework during the metailogenic epoch from the northwestern part of the Jiaodong Peninsula in this paper. A general image of the paleo-crust has been remained although it has been superimposed and reformed by post-metailogenic tectonic movements. The gold ore deposits occur usually in local uplifts and gradient belts featuring a turn from steep to gentle in granite-metamorphic contact zones, relative uplifts of gradient zones of the Curier isothermal interfaces, depressions of the Moho discontinuity and areas where depth contours are cut by isotherms perpendicularly. Gold mineralization and lithogenesis are characterized by high temperature, low pressure and high strength of thermal flux. The depth of mineralization ranges from 0.8 to 4.5 km. The depth of the top interface of the granitic complex in the metallogenic epoch is about 3 km. There is a low-velocity layer （LVL） at the bottom of the upper crust with a depth close to 19.5 km, which may be a detachment belt in the crust. The appearance of the LVL indicates the existence of paleo-hyperthermal fluid or relics of molten magma chambers, which reflects partial melting within the crust during the diagenetic and metallogenic epochs and the superposition effects of strike-slip shearing of the Taulu fault zone. The subsidence of the Moho is probably attributed to the coupling process of the NW-SE continental collision between North China and the Yangtze Block and the strike-slip movement of the Tanlu fault accompanied with underplating of mantle magma in the northwestern part of the Jiaodong Peninsula. The underplating of mantle magma may result in partial melting and make granite magma transfer upwards. This is favorable for the migration of metallogenic materials from deep to shallow to be enriched to form deposits. Coupling interactions between the strike-slip of the Taulu fault, the underplating of mantle magma, partial melting within the crust, and hyperthermal fluid, etc. may be the important factors controlling the gold mineralization and spatial structures in the metailogenic system.

The Effect of High Temperature after Anthesis on Rice Quality and Starch Granule Structure of Endosperm

To ascertain the effect mechanism of high temperature after anthesis on rice quality, the experiment was conducted with two rice lines, the heat-tolerant line 996 and heat-sensitive line 4628, with high temperature and optimal temperature in the growth chamber to investigate the effect of high temperature stress after anthesis on rice appearance quality, milling quality, cooking and eating quality and starch granule structure of endo- sperm. The result showed that milled rice rate, head rice rate, amylose content and gel consistency of both lines decreased under high temperature stress after anthesis, while the ratio of grain length to width, chalky rate, chalkiness, protein content increased. Under high temperature treatments, gelatinization temperature, final viscosity, set back and peak time increased, breakdown decreased, Mg content and K content increased, Mg/K ra- tio decreased. Under same treatment, the extent of rice quality of heat tolerant line 996 affected by high temperature was lower than that of heat sensitive line 4628. Under high temperature stress after anthesis, starch granule arranged untightly, most of starch granules existed in the form of a single starch endosperm, refractive index decreased, transparency reduced, and led to the formation of chalk. Under high temperature stress af- ter anthesis, the increase of protein content, the decrease of Mg/K, the changes of rice RVA profile characteristics and starch granule structure of endosperm could be the main reason for the decrease of rice cooking and eating quality and appearance quality.

Thermoreversible Thickening and Self-assembly Behaviors of pH/Temperature Dually Responsive Microgels with Interpenetrating Polymer Network Structure

The pH /temperature dually responsive microgels of interpenetrating polymer network( IPN) structure composed of poly( N-isopropylacrylamide)( PNIPAM) network and poly( acrylic acid)( PAA) network( PNIPAM /PAA IPN microgels) were synthesized by seed emulsion polymerization. The results obtained by dynamic laser light scattering( DLLS) show that the microgels have good pH /temperature dual sensitivities. The temperature sensitive component and the pH sensitive component inside the microgels have little interference with each other. The rheological properties of the concentrated PNIPAM /PAA IPN microgel dispersions as a function of temperature at pH 4. 0 or 7. 0 were investigated by viscometer,and the results displayed that only at pH 7. 0 the dispersions presented thermoreversible thickening behavior. Then the PNIPAM /PAA fibers were prepared by self-assembly of the PNIPAM /PAA IPN microgels in the ice-crystal templates formed by unidirectional liquid nitrogen freezing method. Field emission scanning electron microscopy( FESEM) images indicate that the PNIPAM /PAA fibers are rounded,randomly orientated and interweaved.

The Liouville integrable coupling system of the m-AKNS hierarchy and its Hamiltonian structure

In this paper a type of 9-dimensional vector loop algebra F is constructed, which is devoted to establish an isospectral problem. It follows that a Liouville integrable coupling system of the m-AKNS hierarchy is obtained by employing the Tu scheme, whose Hamiltonian structure is worked out by making use of constructed quadratic identity. The method given in the paper can be used to obtain many other integrable couplings and their Hamiltonian structures.

Crystal Structure of D-Valine at the Temperature of 293, 270, 223 and 173K

The crystal structure of D-valine has been determined by Mo-Ka (l = 0.71073 ? X-ray diffraction method for the first time. It crystallizes in monoclinic, space group P21 (Z = 4) with a = 9.6728(5), b = 5.2722(3), c = 12.0425(8) ? = 90.750(2)?at 293 K. The asymmetric unit contains two crystallographically independent molecules A (trans form) and B (gauche I form). They are rotational isomers with two kinds of conformations about the Ca Cb bond. The results of measurements of crystal structure at 293, 270, 223 and 173 K show a little change in bond lengths and geometries as a function of temperature. No evidence was obtained for the existence of configuration transformation from D- to L-valine.

Analyses of temperature-dependent interface states,series resistances,and AC electrical conductivities of Al/p Si and Al/Bi_4Ti_3O_(12)/p Si structures by using the admittance spectroscopy method

In this study, Al/p-Si and Al/Bi4Ti3O12/p-Si structures are fabricated and their interface states （Nss）, the values of series resistance （Rs）, and AC electrical conductivity （σac） are obtained each as a function of temperature using admit- tance spectroscopy method which includes capacitance-voltage （C-V） and conductance-voltage （G-V） measurements. In addition, the effect of interfacial Bi4Ti3012 （BTO） layer on the performance of the structure is investigated. The voltage- dependent profiles of Nss and Rs are obtained from the high-low frequency capacitance method and the Nicollian method, respectively. Experimental results show that Nss and Rs, as strong functions of temperature and applied bias voltage, each exhibit a peak, whose position shifts towards the reverse bias region, in the depletion region. Such a peak behavior is attributed to the particular distribution of Nss and the reordering and restructuring of Nss under the effect of temperature. The values of activation energy （Ea）, obtained from the slope of the Arrhenius plot, of both structures are obtained to be bias voltage-independent, and the Ea of the metal-ferroelectric-semiconductor （MFS） structure is found to be half that of the metal-semiconductor （MS） structure. Furthermore, other main electrical parameters, such as carrier concentration of acceptor atoms （NA）, built-in potential （Vbi）, Fermi energy （EF）, image force barrier lowering （△φb）, and barrier height （φb）, are extracted using reverse bias C 2-V characteristics as a function of temperature.

Synthesis of High Surface Area and Well Crystallized Mesoporous WC at Low Temperature with a Pore Structure Collapsed Replication Route

An approach named ＂pore structure collapsed replication route＂ has been developed to prepare mesoporous WC materials with a high surface area （105 m2/g） and crystallized framework at a temperature as low as 700 ℃. The XRD, TEM, EDS, and BET characterizations were conducted to analyze the effects of the synthesis parameters and the template types on the structure of mesoporous WC. The compaction on the templates is the key to form mesoporous structure of WC while the templates help to control the size of crystalline. At a content of 7 wt% for the precursor of WC, the mesoporous WC could be formed with well ordered structure.

Effect of Landform on Seasonal Temperature Structures across China in the Past 52 Years

The data of 160 national meteorological observatory stations including the long-term monthly temperature data in China were analyzed to study the seasonal variation of the spatial temperature structures across China in the past half century. It is found that temperature structures differ between seasons: a latitude temperature pattern in winter and a landform temperature pattern in summer, which indicate that the effect of landform on temperature structure is much stronger in summer than that in winter and the effect of latitudinal temperature is much stronger in winter than that in summer. The mechanisms of the seasonal difference in temperature structures are also discussed in this paper.

Analysis of temperature field for a surface-mounted and interior permanent magnet synchronous motor adopting magnetic-thermal coupling method

Aiming at obtaining high power density of surface-mounted and interior permanent magnet synchronous motor(SIPMSM),it is important to accurately calculate the temperature field distribution of SIPMSM,and a magnetic-thermal coupling method is proposed.The magnetic-thermal coupling mechanism is analyzed.The thermal network model and finite element model are built by this method,respectively.The effects of power frequency on iron losses and temperature fields are analyzed by the magnetic-thermal coupling finite element model under the condition of rated load,and the relationship between the load and temperature field is researched under the condition of the synchronous speed.In addition,the equivalent thermal network model is used to verify the magnetic-thermal coupling method.Then the temperatures of various nodes are obtained.The results show that there are advantages in both computational efficiency and accuracy for the proposed coupling method,which can be applied to other permanent magnet motors with complex structures.

Effects of water on the structure and transport properties of room temperature ionic liquids and concentrated electrolyte solutions

Transport properties and the associated structural heterogeneity of room temperature aqueous ionic liquids and especially of super-concentrated electrolyte aqueous solutions have received increasing attention,due to their potential application in ionic battery.This paper briefly reviews the results reported mainly since 2010 about the liquid-liquid separation,aggregation of polar and apolar domains in neat RTILs,and solvent clusters and 3D networks chiefly constructed by anions in super-concentrated electrolyte solutions.At the same time,the dominating effect of desolvation process of metal ions at electrode/electrolyte interface upon the transport of metal ions is stressed.This paper also presents the current understanding of how water affects the anion-cation interaction,structural heterogeneities,the structure of primary coordination sheath of metal ions and consequently their transport properties in free water-poor electrolytes.

An Analytical Method to Detect the Coupling Damage Relationship of Concrete Subjected to Bending Fatigue and Temperature Actions

Based on the assumptions validated by the experiments,an analytical method to detect the coupling actions of bending fatigue and temperature on concrete was proposed.To this purpose,a coefficient denoted by f D （T）with the strain distributions caused by these two actions was defined.In terms of the known parameters and the fitted functions of strain,the explicit expression for f D （T）which develops in the way same as the law of temperature change in the body of specimens was obtained.Our experimental results indicate that the weigh fraction of temperature stress decreases in the coupling damage field with the fading temperature gradient,and consequently disclose the mutual influence between these two types of actions in the loading history.

A STUDY ON THE STRUCTURE AND PROPERTIES OF POLYBUTYLALDEHYDE FORMED IN LOW TEMPERATURE PLASMA

The polybutylaldehyde obtained by plasma polymerization was investigated by means of IR, X-ray diffraction, GC-MS, elementary analysis, TEM, electron diffraction and contact angle measurements etc. The results showed that the polymer formed in plasma is amorphous crosslinked polymer, and its backbone is made of carbon atoms. The surface energy of the polymer film is independent of the polymerization conditions. No addition reaction has taken place in the carbonyl group of butylaldehyde in the plasma condition. The result of the wettability measurements showed that the polymer film is generally hydrophobic and the surface energy of the film is about 41 dyn/cm, in which the dispersion force contribution is the majority. The electron diffraction proved that some crystal substance, even the single crystals were present in the polymer. X-ray diffraction also proved the presence of crystal and showed about 15% crystaUinity fraction.

Microstructure studies of air-plasma-spray-deposited CoNiCrAlY coatings before and after thermal cyclic loading for high-temperature application

In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying（APS） techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XRD）, and atomic force microscopy（AFM） were used to investigate the phases and microstructure of the as-sprayed, APS-deposited Co Ni Cr Al Y bond-coatings. The aim of this work was to study the suitability of the bond-coat materials for high temperature applications. Confirmation of nanoscale grains of the γ/γ′-phase was obtained by TEM, high-resolution TEM, and AFM. We concluded that these changes result from the plastic deformation of the bond-coat during the deposition, resulting in Co Ni Cr Al Y bond-coatings with excellent thermal cyclic resistance suitable for use in high-temperature applications. Cyclic oxidative stability was observed to also depend on the underlying metallic alloy substrate.