Study on defects detection of a structure undergoing dynamic load

Damages detection method of a long span beam was studied. The beam was designed to subject vibration in order to simulate service station of a real structure. The distributed dynamic strain on the beam was studied. Firstly, in order to reduce the dynamic data discriminate time, a new BOTDA method using amplitude transfer of BFS was applied. At the level of spatial resolution of 10 cm and the sampling interval of 5 cm of the BOTDA system, a sampling frequency for dynamic strain of about 13 Hz was achieved. Secondly, a cracks detection system based on distributed dynamic strain was provided. Most of the time, a real structure is undergoing dynamic load, therefore crack detection system of analyzing distributed dynamic strain was concerned. The work is unlike former research that was based on the distributed static strain analysis. Thirdly, a free vibration experiment was performed on a beam of 15 meters long in order to verify the dynamic crack detection system. In order to local the crack easily, the data from BOTDA were processed. Fourier Transform Analysis was adopted to transfer the distributed dynamic strains from time domain into frequency domain. Test results indicated that the distributed frequency amplitude analysis method provided a practical means to recognize the simulated cracks on the beam undergoing dynamic displacement

Universal Thermoelectric Effect of Dirac Fermions in Graphene

We numerically study the thermoelectric transports of Dirac fermions in graphene in the presence of a strong magnetic field and disorder. We find that the thermoelectric transport coefficients demonstrate universal behavior depending on the ratio between the temperature and the width of the disorder-broadened Landau levels(LLs). The transverse thermoelectric conductivity $\alpha_{xy}$ reaches a universal quantum value at the center of each LL in the high temperature regime, and it has a linear temperature dependence at low temperatures. The calculated Nernst signal has a peak at the central LL with heights of the order of $k_B/e$, and changes sign near other LLs, while the thermopower has an opposite behavior, in good agreement with experimental data. The validity of the generalized Mott relation between the thermoelectric and electrical transport coefficients is verified in a wide range of temperatures.Comment: 4 pages, 4 figures, published versio

Investigation of the interaction between indigotin and two serum albumins by spectroscopic approaches

AbstractThe binding characteristics of indigotin with human serum albumin (HSA) and bovine serum albumin (BSA) have been investigated by various spectroscopic techniques. Spectroscopic analysis revealed that the quenching mechanism between indigotin and HSA/BSA belonged to the static quenching. The displacement experiments suggested that indigotin primarily bound to tryptophan residues on proteins within site I. The thermodynamic parameters indicated that the binding of indigotin–HSA/BSA mainly depended on the hydrophobic interaction. The binding distance of indigotin to HSA/BSA was evaluated. The results by synchronous fluorescence, three-dimensional fluorescence, Fourier Transform Infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra showed that the conformation of proteins altered in the presence of indigotin

Addressing Criticality Levels in Critical Infrastructure System

Abstract-Modern society depends on the operations of critical infrastructure system (CIs), such as transportation, energy, telecommunications, and water. Characterized by direct and transitive interdependencies, these systems have become so interconnected that disruption of one may lead to disruptions in all. The levels in critical infrastructures must firstly be classified in order to make a systemic perspective for critical infrastructure system protection). This paper discusses critical infrastructure interdependencies by highlighting some examples of cascading failure phenomena from references and experts. By utilizing the Interpretive Structural Modeling (ISM) methodology, we analyze the interactions of eight critical infrastructures according to their mutual influences, thereby we identify those driving infrastructures, which can aggravate a few more infrastructure and those dependent infrastructures, which are most influenced by driving infrastructure. It can be also observed that there are some infrastructures, which have both high driving power and dependency, thus needing more attention. The approach taken in this research can form the basis for the analysis of the system of systems that represents the CIs

Research on Winding System of Twisting Machine Based on Multi-parameters

Winding movement of twisting machine is closely related to the package build, package density and yarn quality. The requirements are that the package build is good shaped and the winding tension is proper technically. Namely the angle of winding is fine and there is no overlapping and convex, hard edge on the package. The winding density is same and reasonable on the whole package build. And the fluctuation of winding tension is small. It is becoming development trend that driving of multiple-motors is used on twisting machine. There are many parameters to be controlled such as degree of twist, direction of twist, winding angle and spindle speed and so on. Therefore it is essential to set up reasonable mathematical model of yarn for winding movement