Calculation of stress intensity factor in two-dimensional cracks by strain energy density factor procedure

In order to calculate the stress intensity factor(SIF) of crack tips in two-dimensional cracks from the viewpoint of strain energy density, a procedure to use the strain energy density factor to calculate the SIF is proposed. In this paper, the procedure is presented to calculate the SIF of crack tips in mode I cracks, mode II cracks and I+II mixed mode cracks. Meanwhile, the results are compared to those calculated by traditional approaches or other approaches based on strain energy density and verified by theoretical solutions. Furthermore, the effect of mesh density near the crack tip is discussed, and the proper location where the strain energy density factor is calculated is also studied. The results show that the SIF calculated by this procedure is close to not only those calculated by other approaches but also the theoretical solutions, thus it is capable of achieving accurate results.Besides, the mesh density around the crack tip should meet such requirements that, in the circular area created, the first layer of singular elements should have a radius about 0.05 mm and each element has a circumferential directional meshing angle to be15°–20°. Furthermore, for a single element around the crack tip, the strain energy density factor is suggested to be calculated in the location where half of the sector element's radius from the crack tip.

Anomalous Cell Detection with Kernel Density-Based Local Outlier Factor

Since data services are penetrating into our daily life rapidly, the mobile network becomes more complicated, and the amount of data transmission is more and more increasing. In this case, the traditional statistical methods for anomalous cell detection cannot adapt to the evolution of networks, and data mining becomes the mainstream. In this paper, we propose a novel kernel density-based local outlier factor(KLOF) to assign a degree of being an outlier to each object. Firstly, the notion of KLOF is introduced, which captures exactly the relative degree of isolation. Then, by analyzing its properties, including the tightness of upper and lower bounds, sensitivity of density perturbation, we find that KLOF is much greater than 1 for outliers. Lastly, KLOFis applied on a real-world dataset to detect anomalous cells with abnormal key performance indicators(KPIs) to verify its reliability. The experiment shows that KLOF can find outliers efficiently. It can be a guideline for the operators to perform faster and more efficient trouble shooting.

Vascular endothelial growth factor 165b expression in stromal cells and colorectal cancer

AIM:To characterize the implications of vascular endothelial growth factor(VEGF)-A in stromal cells and colorectal cancer and the expression of VEGF-A splice variants.METHODS:VEGF-A expression in tumor and stromal cells from 165 consecutive patients with colorectal cancer was examined by immunohistochemistry.The association between VEGF-A expression status and clinicopathological factors was investigated.Twenty freshfrozen samples were obtained for laser capture microdissection to analyze the splice variants of VEGF-A.RESULTS:VEGF-A was expressed in 53.9% and 42.4% of tumor and stromal cells,respectively.VEGF-A expression in tumor cells(t-VEGF-A) was associated with advanced clinical stage(stage 0,1/9;stage 1,2/16;stage 2,32/55;stage 3,38/66;stage 4,16/19,P < 0.0001).VEGF-A expression in stromal cells(s-VEGF-A) increased in the earlier clinical stage(stage 0,7/9;stage 1,6/16;stage 2,33/55;stage 3,22/66;stage 4,5/19;P = 0.004).Multivariate analyses for risk factors of recurrence showed that only s-VEGF-A expression was an independent risk factor for recurrence(relative risk 0.309,95% confidence interval 0.141-0.676,P = 0.0033).The five-year disease-free survival(DFS) rates of t-VEGF-A-positive and-negative cases were 51.4% and 62.9%,respectively.There was no significant difference in t-VEGF-A expression status.The five-year DFS rates of s-VEGF-A-positive and-negative cases were 73.8% and 39.9%,respectively.s-VEGFA-positive cases had significantly better survival than s-VEGF-A-negative cases(P = 0.0005).Splice variant analysis revealed that t-VEGF-A was mainly composed of VEGF165 and that s-VEGF-A included both VEGF165 and VEGF165b.In cases with no venous invasion(v0),the level of VEGF165b mRNA was significantly higher(v0 204.5 ± 122.7,v1 32.5 ± 36.7,v2 2.1 ± 1.7,P = 0.03).The microvessel density tended to be lower in cases with higher VEGF165b mRNA levels.CONCLUSION:s-VEGF-A appears be a good prognostic factor for colorectal cancer and includes VEGF165 and VEGF165b.

Analysis of Dynamic Variations of Crustal Density in the Longmenshan Area before the Wenchuan M_S8.0 Earthquake

Based on the repeated gravity observation data from 1996 to 2007 from the Longmenshan gravity network, which has been dealt with by adjustment processing, the benchmark interference removal and impact of elevation changes removal, and by using the 3-D inversion method to reflect underground density, we analyze the characteristics of Longmenshan regional dynamic crustal density at depths of 25km, 20km and 15kin. The results show that in the Wenchuan earthquake preparation process, the regional density field showed marked characteristics both in time and space distribution. From the point of time process, the density change trend in the ten years before the earthquake presents a periodic change pattern： steady phase, dramatic stage, slow reducing phase and slow increase phase. The degree of density changes is from large to small, which means that earthquake gestation has reached the final stage. From the point of space distribution, density change distribution has a tendency of ＂dispersion--relative concentration＂, this shows that before the earthquake, the entropy of the underground density field was decreased. In addition, dramatic density changes often occur in the Longmenshan fault zone and western Sichuan plateau. Also, with the increase of depth, the trend of density change is more and more obvious. Through comparative analysis, the influence of density change on gravity is much bigger than that from height change.

TORSIONAL IMPACT RESPONSE OF A PENNY-SHAPED CRACK IN A FUNCTIONAL GRADED STRIP

The torsional impact response of a penny-shaped crack in a nonhomogeneous strip is considered. The shear modulus is assumed to be functionally graded such that the mathematics is tractable. Laplace and Hankel transforms were used to reduce the problem to solving a Fredholm integral equation. The crack tip stress field is obtained by considering the asymptotic behavior of Bessel function. Explicit expressions of both the dynamic stress intensity factor and the energy density factor were derived.And it is shown that, as crack driving force, they are equivalent for the present crack problem. Investigated are the effects of material nonhomogeneity and (strip's) highness on the dynamic fracture behavior. Numerical results reveal that the peak of the dynamic stress intensity factor can be suppressed by increasing the nonhomogeneity parameter of the shear modulus, and that the dynamic behavior varies little with the adjusting of the strip's highness.

Calculation of b value and its application in earthquake prediction

The improved calculation method of b value is presented in tills paper. The method can enlarge the role of earthquake occurrence frequency in b value calculation and thus increase the b value variation amplitude. In this case,the combination structure variation between earthquake magnitudes and corresponding frequencies could be shown clearly. According to the calculation and analysis for limited mainshocks in the complete seismicity data of selected monitored area with assigned consistent lowest magnitude, the precursor anomaly features, quantitative indexes and the calculation formula of relative subject function of b value variation have been preliminarily worked out. The prediction in short period (from 1 to 3 months) for damage earthquakes in the monitored area mentioned above can be put forward on the basis of the results of quantitative calculation and analysis.

Modeling Integrated Coastal Flood Hazard in Hurricane Season

The manuscript proposed a procedure designed to determine the hazard of total coastal flooding during the impact of hurricanes, which uses in its formulation the combination of river flooding and that caused by marine upwelling, which is multiplied by a density factor of the water that finds an explanation for the effect is shielding and rising of the water level when the currents of both floods collide in the coastal zone. The application of the procedure experimentally in the coastal sector Sevilla, of the municipality Guama province Santiago de Cuba, resulting in the confirmation of areas previously modeled and estimated coastal flooding in the wake of extreme weather events in the study area;in addition to other new areas that confirm the actual visual and instrumental observations not included in previous studies.

An Intelligent Early Warning Method of Press-Assembly Quality Based on Outlier Data Detection and Linear Regression

Focusing on controlling the press-assembly quality of high-precision servo mechanism,an intelligent early warning method based on outlier data detection and linear regression is proposed.Linear regression is used to deal with the relationship between assembly quality and press-assembly process,then the mathematical model of displacement-force in press-assembly process is established and a qualified press-assembly force range is defined for assembly quality control.To preprocess the raw dataset of displacement-force in the press-assembly process,an improved local outlier factor based on area density and P weight(LAOPW)is designed to eliminate the outliers which will result in inaccuracy of the mathematical model.A weighted distance based on information entropy is used to measure distance,and the reachable distance is replaced with P weight.Experiments show that the detection efficiency of the algorithm is improved by 5.6 ms compared with the traditional local outlier factor(LOF)algorithm,and the detection accuracy is improved by about 2%compared with the local outlier factor based on area density(LAOF)algorithm.The application of LAOPW algorithm and the linear regression model shows that it can effectively carry out intelligent early warning of press-assembly quality of high precision servo mechanism.

Determining the relationship between chemical composition and size, shape and effective density of airborne fine particles through concurrent use of inertial and optical based measurements

This study presents the development of a medium flow, multiple slit based PM2.5 （particle aerodynamic diameter 〈2.5 μm） inertial impactor. Its performance was compared with that of a light scattering based optical particle sizer in a field study and in controlled lab based experiments using polydisperse dolomite powder as test aerosol. The impactor＇s optimum nozzle configuration had a cutoff size of 2.51 μm （aero- dynamic diameter） at an operating flow rate of 215 L/rain with a pressure drop of 0.35 kPa across the impactor stage. Because the apparent particle density of an ambient aerosol depends on the physical properties and the chemical composition of the particles, the PM2.5 mass concentration was measured with an optical particle sizer and an inertial impactor over a weekday and a weekend day in a field study during which the effective particle shape factor and density were in tandem modified in order to com- pare the results from the two sampling techniques. The correlation of the two instrument results tended towards 1：1 with increasing values of shape factor （irregular shaped） and effective particle density. This observation was supported through chemical investigations of the collected mass, which showed a higher percentage contribution from elements which are mostly of crustal nature （namely, Ca, Fe, and Mg）.

Baryon structure from Lattice QCD

We present recent lattice results on the baryon spectrum, nucleon electromagnetic and axial form factors, nucleon to △ transition form factors as well as the △ electromagnetic form factors. The masses of the low lying baryons and the nucleon form factors are calculated using two degenerate flavors of twisted mass fermions down to pion mass of about 270 MeV. We compare to the results of other collaborations. The nucleon to △ transition and △ form factors are calculated in a hybrid scheme, which uses staggered sea quarks and domain wall valence quarks. The dominant magnetic dipole nucleon to △ transition form factor is also evaluated using dynamical domain wall fermions. The momentum frame are extracted using the form factors transverse density distributions of the △ in the infinite determined from lattice QCD.