Quantitatively characterizing sandy soil structure altered by MICP using multi-level thresholding segmentation algorithm

The influences of biological,chemical,and flow processes on soil structure through microbially induced carbonate precipitation(MICP)are not yet fully understood.In this study,we use a multi-level thresholding segmentation algorithm,genetic algorithm(GA)enhanced Kapur entropy(KE)(GAE-KE),to accomplish quantitative characterization of sandy soil structure altered by MICP cementation.A sandy soil sample was treated using MICP method and scanned by the synchrotron radiation(SR)micro-CT with a resolution of 6.5 mm.After validation,tri-level thresholding segmentation using GAE-KE successfully separated the precipitated calcium carbonate crystals from sand particles and pores.The spatial distributions of porosity,pore structure parameters,and flow characteristics were calculated for quantitative characterization.The results offer pore-scale insights into the MICP treatment effect,and the quantitative understanding confirms the feasibility of the GAE-KE multi-level thresholding segmentation algorithm.

Preliminary investigation of seismic damage to two steel space structures during the 2013 Lushan earthquake

Severe damage to steel space structures is rarely reported when compared to other structural systems damaged during past major earthquakes around the world. Two gymnasiums of steel space structures in downtown Lushan County that were damaged during the 2013 M7.0 Lushan earthquake in China were investigated and the observations are summarized in this paper. Typical damage to these two steel space structures ranges from moderate to severe. Moderate damage includes global buckling and dislocation of bolted connections of truss members, and inelastic elongation of anchor bolts and sliding of pedestal plates of supports. Severe damage includes member fracture caused by local buckling, and fracture failure of anchor bolts and welds. The distribution of structural damage to these two structures is described in detail and future research opportunities are suggested.

Recent Advances in Space-Deployable Structures in China

Deployable space structure technology is an approach used in building spacecraft,especially when realizing deployment and folding functions.Once in orbit,the structures are released from the fairing,deployed,and positioned.With the development of communication,remote-sensing,and navigation satellites,space-deployable structures have become cutting-edge research topics in space science and technology.This paper summarizes the current research status and development trend of spacedeployable structures in China,including large space mesh antennas,space solar arrays,and deployable structures and mechanisms for deep-space exploration.Critical technologies of space-deployable structures are addressed from the perspectives of deployable mechanisms,cable-membrane form-finding,dynamic analysis,reliable environmental adaptability analysis,and validation.Finally,future technology developments and trends are elucidated in the fields of mesh antennas,solar arrays,deployable mechanisms,and on-orbit adjustment,assembly,and construction.

A Multi-level Approach for Complex Fault Isolation Based on Structured Residuals

In industrial processes,there exist faults that have complex effect on process variables.Complex and simple faults are defined according to their effect dimensions.The conventional approaches based on structured residuals cannot isolate complex faults.This paper presents a multi-level strategy for complex fault isolation.An extraction procedure is employed to reduce the complex faults to simple ones and assign them to several levels.On each level,faults are isolated by their different responses in the structured residuals.Each residual is obtained insensitive to one fault but more sensitive to others.The faults on different levels are verified to have different residual responses and will not be confused.An entire incidence matrix containing residual response characteristics of all faults is obtained,based on which faults can be isolated.The proposed method is applied in the Tennessee Eastman process example,and the effectiveness and advantage are demonstrated.

Switching disturbance rejection attitude control of near space vehicles with variable structure

A switching disturbance rejection attitude control law is proposed for a near space vehicle(NSV) with variable structure.The multiple flight modes, system uncertainties and disturbances of the NSV are taken into account based on switched nonlinear systems. Compared with traditional backstepping design methods,the proposed method utilizes the added integrals of attitude angle and angular rate tracking errors to further decrease the tracking errors. Moreover, to reduce the computation complexity, a rapid convergent differentiator is employed to obtain the derivative of the virtual control command. Finally, for disturbance rejection, based on the idea from the extended state observer(ESO), two disturbance observers are designed by using non-smooth functions to estimate the disturbances in the switched nonlinear systems. All signals of the closed-loop system are proven to be uniformly ultimately bounded under the Lyapunov function framework. Simulation results demonstrate the effectiveness of the proposed control scheme.

Research on Full Space Transient Electro-magnetism Technique for Detecting Aqueous Structures in Coal Mines

Based on the transmitting theory of "smoke ring effect", the transient electromagnetism technique was used in coal mines to detect abnormal areas of aquiferous structures in both roofs and floors of coal seams and in front of excavated roadways. Survey devices, working methods and techniques as well as data processing and interpretation are discussed systematically. In addition, the direction of mini-wireframe emission electromagnetic wave of the full space transient electromagnetism technique was verified by an underground borehole for water detection and drainage. The result indicates that this technique can detect both horizontal and vertical development rules of abnormal water bodies to a certain depth below the floor of coal seams and can also detect the abnormal, low resistance water bodies within a certain distance of roofs. Furthermore, it can detect such abnormal bodies in ahead of the excavated roadway front. Limited by the underground environment, the full space transient electromagnetism technique can detect to a depth of only 120 m or so.

A New Class of Banach Spaces with Uniform Normal Structure

Let X be a Banach space, S(X) be the unit sphere of X, φ be a function: S(X)→ S(X *) such that φ(x)∈ x, and v φ(ε) =inf 1-12x+y: x,y∈S(X), and 〈φ(x), x-y 〉≥ε, 0≤ε≤2, where x is the set of norm 1 supporting functionals of S(X) at x. A geometric concept, modulus of V convexity V(ε)= sup {V φ(ε), for all φ: S(X)→S(X *)}, is introduced; the properties of V(ε) and the relationship between V(ε) and other geometric concepts are discussed. The main result is that V12>0 implies normal structure.

Structured Light 3D Vision Based on Laser Scanning Space-encoding and Its Synchro Control

This paper presents the principle and mathematic model for the 3D depth map method based on space encoding images performed by modulating scanning structuredlight according to time sequences,and the synchro control among the camera,laser diode modulation and scanning polyhedron.

Regulation effect of the grille spacing of a funnel-type grating water–sediment separation structure on the debris flow performance

The size of pores or the grille spacing of water–sediment separation structures directly affects their regulation effect on the debris flow performance.A suitable pore size or grille spacing can effectively improve the water–sediment separation ability of the structure.The new funnel-type grating water–sediment separation structure(FGWSS)combines vertical and horizontal structures and provides a satisfactory water–sediment separation effect.However,the regulation effect of the grille spacing of the structure on the debris flow performance has not been studied.The regulation effect of the structure grille spacing on the debris flow performance is studied through a flume test,and the optimal structure grille spacing is obtained.An empirical equation of the relationship between the relative grille spacing of the structure and the sediment separation rate is established.Finally,the influence of the water–sediment separation structure on the regulation effect of debris flows is examined from two aspects:external factors(properties of debris flows)and internal factors(structural factors).The experimental results show that the gradation characteristics of solid particles in debris flows constitute a key factor affecting the regulation effect of the structure on the debris flow performance.The optimum grille spacing of the FGWSS matches the particle size corresponding to the material distribution curves d85~d90 of the debris flow.The total separation rate of debris flow particles is related to the grille spacing of the structure and the content of coarse and fine particles in the debris flow.

Variation in Pore Space and Structure of Organic-rich Oilprone Shales from a Non-marine Basin:Constraints from Organic Matter and Minerals

Organic matter(OM)and minerals are major particle components of lacustrine shales.The influence of OM and minerals on pore space and structure in organic-rich oil-prone shales containing a large range of total organic carbon(TOC)contents is poorly understood.In this study,we investigated the variation in pore space and structure of low mature lacustrine shales in the Songliao Basin(NE China),based on a study of the mineralogy,petrography,geochemistry,and geophysical properties of shales.Different pore types make markedly different contributions to the mineral surface area(MSA)and pore volume(PV)of the shales.There exists a negative correlation between MSA/PV and TOC in mesopores(r^(2)=0.75/0.65)and macropores(r^(2)=0.74/0.68),and a positive correlation in micropores(r^(2)=0.59/0.64),which are associated with the variation of mineral and TOC contents.A positive relationship between the throat/pore ratio and TOC(r^(2)=0.82)shows an increase in throat radius and decrease in pore radius with increasing TOC content.This relationship is supported by the reduction in mean pore diameter(MPD)for large pores and increase in MPD for small pores.These variations are related to the decreased pores by quartz plus feldspar(Q+F)content,increased throats by clay minerals,an d enhanced pore-fill by OM.We propose that the variation of OM and minerals is a key control on the pore space and structure of low mature organic-rich oil-prone shales.

Investigation and Analysis of Urban Spatial Structure around the Train Stations in Kitakyushu by Using Space Syntax and GIS

Although many methods of spatial analysis have been developed for a better understanding and modelling of urban space analysis, there is still a need for exploration of new analytical techniques for modelling urban spaces. Space Syntax models the spatial configurations of urban spaces by using a connectivity graph representation. Such a configuration of space identifies patterns that can be used to study urban structures and human behaviors. This paper tries to present a new methodology to investigate the urban spatial structure by using Space Syntax with the GIS information including land use, buildings’ characteristics and practical evaluations of the potential of the Space Syntax approach with GIS and multivariate analysis technique. Finally we try to offer some recommendations that attempt to improve the identified problems faced in Kitakyushu, Japan.

Improved Fibroblast Adhesion and Proliferation by Controlling Multi-level Structure of Polycaprolactone Microfiber

Improving wound healing efficiency is a key issue for high performance dressings.The surface topology of fibers in wound dressings plays an important role in regulating cell behaviors during the regeneration.Herein,a polycaprolactone(PCL)scaffold with a shish-kebab structure was prepared by electrospinning and solution-induced crystallization.L929 cells were used to investigate the behavior of fibroblasts on the multi-level microfiber.The results showed that the shish-kebab fiber-based scaffold enhanced the cell proliferation when compared with the normal fiber and the fiber with a porous structure.Protein absorption,cell adhesive force,and cell modulus also increased by the shish-kebab fiber.The shish-kebab fiber-based scaffold with improved fibroblast-regulation ability can be applied in rapid wound healing.

The Space Structure, Force Fields, and Dark Matter

It is proposed that the digital space structure consists of attachment space (denoted as 1) for rest mass and detachment space (denoted as 0) for kinetic energy. Attachment space attaches to object permanently with zero speed, and detachment space detaches from the object at the speed of light. The combination of attachment space and detachment space brings about the three structures: binary lattice space, miscible space, and binary partition space. Binary lattice space, (1 0)n, consists of repetitive units of alternative attachment space and detachment space. In miscible space, attachment space is miscible to detachment space without separation. Binary partition space, (1)n(0)n, consists of separated continuous phases of attachment space and detachment space. Binary lattice space, miscible space, and binary partition space constitute quantum mechanics, special relativity, and the extreme force fields, respectively. Through the detachment space, a higher dimensional particle in attachment space is sliced into infinitely surrounding a lower dimensional core attachment space, resulting in a particle surrounding by gauge field in the form of binary lattice space. The 10d particle can be sliced into 9d, 8d, 7d, 6d, 5d, and 4d particles equally by mass, corresponding to baryonic particle as 4d and dark matter as other 5 particles, so the ratio between baryonic matter and dark matter is 1 to 5, in agreement with the observed ratio. At extreme conditions, such as extremely low temperature, the gauge force field in the form of binary lattice space is transformed into the extreme force field in the form of binary partition space to explain extreme phenomena, such as superconductivity.

The rough representation and measurement of quotient structure in algebraic quotient space model

Granular computing is a very hot research field in recent years. In our previous work an algebraic quotient space model was proposed,where the quotient structure could not be deduced if the granulation was based on an equivalence relation. In this paper,definitions were given and formulas of the lower quotient congruence and upper quotient congruence were calculated to roughly represent the quotient structure. Then the accuracy and roughness were defined to measure the quotient structure in quantification. Finally,a numerical example was given to demonstrate that the rough representation and measuring methods are efficient and applicable. The work has greatly enriched the algebraic quotient space model and granular computing theory.

Sequence Planning for On-Orbit Assembly of Large Space Truss Structures in a Multirobot Environment

An approach to sequence planning for on-orbit assembly of large space truss structures in a multirobot environment is presented. A hierarchical representation of large space truss structures at the structural volume element level and strut level is adopted. The representation of connectivity matrix and directed graph is respectively presented at the strut level and SVE level. The multirobot environment that consists of autonomous space robots and struts is supposed. Then the multirobot serial assembly strategy,assembly states,assembly tasks and assembly sequences are described. The assembly sequence planning algorithms at the strut level and SVE level are respectively discussed. The results of the simulations show that this approach is feasible and efficient. Two extensions of this approach include more accurate assessment of the efficiency representation and improvements in planning algorithm. In the future,the assembly sequence planning of more large space truss structures and complex multirobot environments and assembly tasks will be considered.

Development of “Parameter space screening”-based single-wavelength anomalous diffraction phasing and structure determination pipeline

In this paper, we present a highly efficient structure determination pipeline software suite(X^2 DF) that is based on the "Parameter space screening" method, by combining the popular crystallographic structure determination programs and high-performance parallel computing. The phasing method employed in X^2 DF is based on the single-wavelength anomalous diffraction(SAD) theory. In the X^2 DF, the choice of crystallographic software, the input parameters to this software and the results display layout, are all parameters which users can select and screen automatically. Users may submit multiple structure determination jobs each time, and each job uses a slightly different set of input parameters or programs. Upon completion, the results of the calculation performed can be displayed, harvested, and analyzed by using the graphical user interface(GUI) of the system. We have applied the X^2 DF successfully to many cases including the cases that the structure solutions fail to be yielded by using manual approaches.

Multi-level Flocculation Structures of Fresh Cement Paste by Confocal Laser Scanning Microscope

Under saturation dosage of all kinds of SP, the free water amount was examined by centrifuge. The distribution of solution and flocculation microstructures in fresh cement paste was observed in three- dimensional space by confocal laser scanning microscope（CLSM）. Results indicate that SP can increase the free water amount by destroying the flocculated cement particle structure and different free water amount is released by different kinds of SP. The changes of the size of flocculation structures and the dispersion of solution were obviously detected with confocal laser scanning microscope： the size of flocculation structures was smaller and more dispersed in fresh cement paste with polycarboxylate superplasticizer, but the size of flocculation structures was bigger and cannot be dispersed uniformly in fresh cement paste with others SP. The multi- level flocculation structures theoretical model of fresh cement paste was then set up. The theory indicates that different kinds of SP with different dispersion strength will open the flocculation structures at different levels, which in turn present different water reducing rate.

Commuting Structure Jacobi Operator for Real Hypersurfaces in Complex Space Forms

Let M be a real hypersurface of a complex space form with almost contact metric structure (φ,ξ,η,g). In this paper, we prove that if the structure Jacobi operator Rξ=(·,ξ) ξ is φ▽ξξ-parallel and Rξ commute with the shape operator, then M is a Hopf hypersurface. Further, if Rξ is φ▽ξξ-parallel and Rξ commute with the Ricci tensor, then M is also a Hopf hypersurface provided that TrRξ is constant.

COINCIDENCE POINT THEOREMS iN PROBABILISTIC METRIC SPACES WITH A CONVEX STRUCTURES

In lhis paper we draw some coincidence and common fixed point theorems fornonlinear hybrid contraction mappings on probabilistic metric spaces with a convexstructure.

Torsional effect of space structure in frequent earthquakes

Taking a concrete frame supporting space structure as the research object,we systematically studied its lateral-torsion coupling effect of reverse problems in consistent earthquake excitation.Firstly,based on its reverse forms and features,we put forward a mechanical analysis model(flexibility layer model) and a calculation method using the response spectrum method and the weighted average method,and verified their validity and feasibility using case analysis.The result shows that the translation displacement change trend of the space structure is basically the same whether reverse exists in the supporting structure or not,but the supporting structure torsion has an effect on the displacement with a relative increase of 10%.