Bending of steel fibers on partly supported elastic foundation

Hu, Xiao Dong,Day, Robert,Dux, Peter Techno-Press 2001 Structural Engineering and Mechanics, An Int'l Jou Vol.12 No.6

Fiber reinforced cementitious composites are nowadays widely applied in civil engineering. The postcracking performance of this material depends on the interaction between a steel fiber, which is obliquely across a crack, and its surrounding matrix. While the partly debonded steel fiber is subjected to pulling out from the matrix and simultaneously subjected to transverse force, it may be modelled as a Bernoulli-Euler beam partly supported on an elastic foundation with non-linearly varying modulus. The fiber bridging the crack may be cut into two parts to simplify the problem (Leung and Li 1992). To obtain the transverse displacement at the cut end of the fiber (Fig. 1), it is convenient to directly solve the corresponding differential equation. At the first glance, it is a classical beam on foundation problem. However, the differential equation is not analytically solvable due to the non-linear distribution of the foundation stiffness. Moreover, since the second order deformation effect is included, the boundary conditions become complex and hence conventional numerical tools such as the spline or difference methods may not be sufficient. In this study, moment equilibrium is the basis for formulation of the fundamental differential equation for the beam (Timoshenko 1956). For the cantilever part of the beam, direct integration is performed. For the non-linearly supported part, a transformation is carried out to reduce the higher order differential equation into one order simultaneous equations. The Runge-Kutta technique is employed for the solution within the boundary domain. Finally, multi-dimensional optimization approaches are carefully tested and applied to find the boundary values that are of interest. The numerical solution procedure is demonstrated to be stable and convergent.

Study on Residual Stress Releasing of 316L Stainless Steel Welded Joints by Ultrasonic Impact Treatment

Xiao-Dong Hu,Chongbin Ma,Yicheng Yang,Qingliang Zeng 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.3

In this paper, the eff ect of ultrasonic impact treatment (UIT) on the residual stress of 316L welded butt-joint was investigated. Firstly, the temperature fi eld distribution in the welded joint was simulated based on the double-ellipsoidal heat source model, and the residual stresses were calculated by a sequential coupling thermo-mechanical fi nite element method. Subsequently, based on the theory of transient contact mechanics, the eff ects of UIT on releasing of the welding residual stress was analyzed. The microstructure of the weld metal before and after the UIT treatment was compared to study the infl uence of UIT. The results show that the maximum residual stresses in the weld metal and heat aff ected zones are released due to the dislocation multiplication during the UIT, and this eff ect on the weld metal is more remarkable than that on the heat aff ected zones. The results of numerical simulation of UIT are consistent with the corresponding experimental results. After UIT, the transverse and longitudinal tensile stresses near the fusion line are changed to compressive stresses.

Proteomic Profiles of Mouse Neuro N2a Cells Infected with Variant Virulence of Rabies Viruses

( Wang Xiao Hu ),( Shou Feng Zhang ),( Cheng Long Sun ),( Zi Guo Yuan ),( Xian Fu Wu ),( Dong Xia Wang ),( Zhuang Ding ),( Rong Liang Hu ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.4

We characterized the proteomes of murine N2a cells following infection with three rabies virus (RV) strains, characterized by distinct virulence phenotypes (i.e., virulent BD06, fixed CVS-11, and attenuated SRV9 strains), and identified 35 changes to protein expression using twodimensional gel electrophoresis in whole-cell lysates. The annotated functions of these proteins are involved in various cytoskeletal, signal transduction, stress response, and metabolic processes. Specifically, a-enolase, prx-4, vimentin, cytokine-induced apoptosis inhibitor 1 (CIAPIN1) and prx-6 were significantly up-regulated, whereas Trx like-1 and galectin-1 were down-regulated following infection of N2a cells with all three rabies virus strains. However, comparing expressions of all 35 proteins affected between BD06-, CVS-11-, and SRV9-infected cells, specific changes in expression were also observed. The up-regulation of vimentin, CIAPIN1, prx-4, and 14-3-3 θ/δ, and downregulation of NDPK-B and HSP-1 with CVS and SRV9 infection were ≥2 times greater than with BD06. Meanwhile, Zfp12 protein, splicing factor, and arginine/serine-rich 1 were unaltered in the cells infected with BD06 and CVS- 11, but were up-regulated in the group infected with SRV9. The proteomic alterations described here may suggest that these changes to protein expression correlate with the rabies virus`` adaptability and virulence in N2a cells, and hence provides new clues as to the response of N2a host cells to rabies virus infections, and may also aid in uncovering new pathways in these cells that are involved in rabies infections. Further characterization of the functions of the affected proteins may contribute to our understanding of the mechanisms of RV infection and pathogenesis.

Robotic versus Laparoscopic Gastrectomy for Gastric Carcinoma: a Meta-Analysis of Efficacy and Safety

Hu, Li-Dong,Li, Xiao-Fei,Wang, Xiu-Yue,Guo, Tian-Kang Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.9

Purpose: To systematically review efficacyand safety of robotic gastrectomy (RG) compared with conventional laparoscopic gastrectomy (LG) for gastric carcinoma. Materials and Methods: A systematic literature search was carried out using PubMed, Cochrane Library, CBM, CNKI, WanFang, VIP and other sources like relevant references to obtain comparative studies assessing the effectiveness and safety between RG and LG published between 2013 and 2016. Then the literature was screened and the data were extracted by 2 independent reviewers. The quality of the literature was assessed, and the data analyzed using Stata/SE 14 software. Fixed effects or random effects models wereapplied according to heterogeneity. Results: A total of 12 non-randomized observational clinical studies involving 3,580 patients were included, of which 1,096 had undergone RG and 2,484 had received LG. The results of the meta-analysis showed in terms of effectiveness, RG was associated with less blood loss, less time to first flatus and greater number of harvested lymph nodes, but there were no significant differences in proximal and distal resection margins, compared with LG. In terms of efficiency, RG was associated with shorter hospital stay, but longer operative time. In terms of safety, there were no statistically significant differences in complications, mortality and conversions between RG and LG. Conclusions: RG can achieve comparable or better short-term and radical effects than LG, with respect to effectiveness, efficiency and safety in treatment of gastric carcinoma. Future studies involving RG should focus on decreasing operative time and reducing cost. Moreover, there is a need for randomized controlled trials comparing the two techniques with long-term follow-up.

Investigation on alkalinity of pore solution and microstructure of hardened cement-slag pastes in purified water

Hu, Ya-Ru,Zuo, Xiao-Bao,Li, Xiang-Nan,Jiang, Dong-Qi Techno-Press 2021 Advances in concrete construction Vol.12 No.6

To evaluate the influence of slag on the alkalinity of pore solution and microstructure of concrete, this paper performs a leaching experiment on hardened cement-slag pastes (HCSP) slice specimens with different slag content in purified water. The pH value of pore solution, average porosity, morphology, phase composition and Ca/Si of HCSP specimens in the leaching process are measured by solid-liquid extraction, saturated-dried weighing, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) and X-ray diffraction (XRD). Results shows that the addition of slag can mitigate an increase in porosity and a decrease in Ca/Si of HCSP in the leaching process. Besides, an appropriate slag content can improve the microstructure so as to obtain the optimum leaching resistance of HCSP, which can guarantee the suitable alkalinity of pore solution to prevent a premature corrosion of reinforced bar. The optimum slag content is 40% in HCSP with a water-binder ratio of 0.45, and an excessive slag causes a significant decrease in the alkalinity of pore solution, resulting in a loss of protection on reinforced bar in HCSP.

Augmenter of Liver Regeneration Alleviates Renal Hypoxia-Reoxygenation Injury by Regulating Mitochondrial Dynamics in Renal Tubular Epithelial Cells

Xiao-hui Liao,Rui-ting Long,Jun-bo Peng,Li-li Huang,Gui-ping Jiang,Yue-juan Liao,Hang Sun,Yu-dong Hu 한국분자세포생물학회 2019 Molecules and cells Vol.42 No.12

Mitochondria are highly dynamic organelles that constantly undergo fission and fusion processes that closely related to their function. Disruption of mitochondrial dynamics has been demonstrated in acute kidney injury (AKI), which could eventually result in cell injury and death. Previously, we reported that augmenter of liver regeneration (ALR) alleviates renal tubular epithelial cell injury. Here, we gained further insights into whether the renoprotective roles of ALR are associated with mitochondrial dynamics. Changes in mitochondrial dynamics were examined in experimental models of renal ischemia-reperfusion (IR). In a model of hypoxia-reoxygenation (HR) injury in vitro, dynamin-related protein 1 (Drp1) and mitochondrial fission process protein 1 (MTFP1), two key proteins of mitochondrial fission, were downregulated in the Lv-ALR + HR group. ALR overexpression additionally had an impact on phosphorylation of Drp1 Ser637 during AKI. The inner membrane fusion protein, Optic Atrophy 1 (OPA1), was significantly increased whereas levels of outer membrane fusion proteins Mitofusin-1 and -2 (Mfn1, Mfn2) were not affected in the Lv-ALR + HR group, compared with the control group. Furthermore, the mTOR/4E-BP1 signaling pathway was highly activated in the Lv-ALR + HR group. ALR overexpression led to suppression of HR-induced apoptosis. Our collective findings indicate that ALR gene transfection alleviates mitochondrial injury, possibly through inhibiting fission and promoting fusion of the mitochondrial inner membrane, both of which contribute to reduction of HK-2 cell apoptosis. Additionally, fission processes are potentially mediated by promoting tubular cell survival through activating the mTOR/4E-BP1 signaling pathway.

Synthesis of nonsharp distillation sequences via genetic programming

Xiao-Hong Wang†,,Yang-Dong Hu,Yu-Gang Li 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.3

This paper addresses the application of Genetic Programming (GP) to the synthesis of multicomponent product nonsharp distillation sequences. Combined with the domain knowledge of chemical engineering, some evolutionary factors are improved, and a set of special encoding method and solving strategy is proposed to deal with this kind of problem. The system structural variable is optimized by GP and the continuous variable is optimized by the simulated annealing algorithm simultaneously. Because GP has an automatic searching function, the optimal solution can be found including distillation, splitting, blending and bypassing operations automatically without any superstructures of nonsharp distillation sequences. Three illustrative examples are presented to demonstrate the effective computational strategies.

Research on diagnosis method of centrifugal pump rotor faults based on IPSO-VMD and RVM

Dong Liang,Chen Zeyu,Hua Runan,Hu Siyuan,Fan Chuanhan,Xiao xingxin 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.3

Centrifugal pump is a key part of nuclear power plant systems, and its health status is critical to the safety and reliability of nuclear power plants. Therefore, fault diagnosis is required for centrifugal pump. Traditional fault diagnosis methods have difficulty extracting fault features from nonlinear and nonstationary signals, resulting in low diagnostic accuracy. In this paper, a new fault diagnosis method is proposed based on the improved particle swarm optimization (IPSO) algorithm-based variational modal decomposition (VMD) and relevance vector machine (RVM). Firstly, a simulation test bench for rotor faults is built, in which vibration displacement signals of the rotor are also collected by eddy current sensors. Then, the improved particle swarm algorithm is used to optimize the VMD to achieve adaptive decomposition of vibration displacement signals. Meanwhile, a screening criterion based on the minimum Kullback-Leibler (K-L) divergence value is established to extract the primary intrinsic modal function (IMF) component. Eventually, the factors are obtained from the primary IMF component to form a fault feature vector, and fault patterns are recognized using the RVM model. The results show that the extraction of the fault information and fault diagnosis classification have been improved, and the average accuracy could reach 97.87%.

Prediction of Equivalent Chloride Ion Diffusion Coefficient in Cracked Concrete of the in-Service RC Element

Xiao-Hui Wang,Dong-Gang Hu,Ahmad Kueh Beng Hong,Dan-Da Shi 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.5

Considering the influence of the visible load-induced transverse cracks on chloride ion diffusion in cracked concrete of the in-service reinforced concrete (RC) elements under marine environment, a typical concrete volume with one transverse crack was taken to establish the governing equation. Assuming the crack widths at the outer lateral and bottom surfaces were equal, a model to predict the equivalent chloride diffusion coefficient in cracked concrete was put forward to consider the influence of the average transverse crack width, crack spacing and crack extending lengths in beam height and width directions on chloride diffusion. Results show that the proposed model can better reflect the variation trend of the equivalent chloride diffusion coefficient with different crack widths in in-service RC elements under marine environment.

Knockdown of the olfactory co-receptor Orco impairsmate recognition in Tenebrio molitor (Coleoptera: Tenebrionidae)

Xiao-Ming Liu,Bang-Xian Zhang,Shi-Guang Li,Xiang-Jun Rao,Dong-MingWang,Xiao-Xuan Hu,Su Liu 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.2

The yellow mealworm beetle, Tenebrio molitor (Coleoptera: Tenebrionidae), is a common insect pest that damages stored grain. The insect olfactory co-receptor (Orco) is a transmembrane protein localized on the surface of the dendrites of olfactory sensory neurons and plays an essential role in the olfactory perception. In this study, an Orco ortholog (named as Tmol\Orco) inT.molitorwas characterized. The deduced amino acid sequence of Tmol\Orco shared significant high identities with Orcos in other insect species from distinct Orders. Reverse transcription quantitative PCR (RT-qPCR) analysis showed that Tmol\Orco was predominantly expressed in the antennae of both male and female adults, and the difference between male antennae and female antennae was not significant. Double-stranded RNA (dsRNA) directly against the Tmol\Orco mRNA was synthesized and injected into the T. molitor male adults, RT-qPCR results demonstrated that the transcription level of Tmol\Orco was significantly reduced at 6 d after the injection. The mate-seeking behavior of Tmol\Orco-silenced beetles was significantly inhibited. Compare to the control individuals, the percentage of Tmol\Orco-silenced beetles successfully find mateswas significantly decreased and the average time they spent for searching were significantly increased. These results provided first direct evidence that suppression of Tmol\Orco transcription contributes to the decline in mate recognition of T. molitor