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Indirect structural health monitoring of a simplified laboratory-scale bridge model
Cerda, Fernando,Chen, Siheng,Bielak, Jacobo,Garrett, James H.,Rizzo, Piervincenzo,Kovacevic, Jelena Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.13 No.5
An indirect approach is explored for structural health bridge monitoring allowing for wide, yet cost-effective, bridge stock coverage. The detection capability of the approach is tested in a laboratory setting for three different reversible proxy types of damage scenarios: changes in the support conditions (rotational restraint), additional damping, and an added mass at the midspan. A set of frequency features is used in conjunction with a support vector machine classifier on data measured from a passing vehicle at the wheel and suspension levels, and directly from the bridge structure for comparison. For each type of damage, four levels of severity were explored. The results show that for each damage type, the classification accuracy based on data measured from the passing vehicle is, on average, as good as or better than the classification accuracy based on data measured from the bridge. Classification accuracy showed a steady trend for low (1-1.75 m/s) and high vehicle speeds (2-2.75 m/s), with a decrease of about 7% for the latter. These results show promise towards a highly mobile structural health bridge monitoring system for wide and cost-effective bridge stock coverage.
Indirect structural health monitoring of a simplified laboratory-scale bridge model
Fernando Cerda,Siheng Chen,Jacobo Bielak,James H. Garrett,Piervincenzo Rizzo,Jelena Kovačević 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.13 No.5
An indirect approach is explored for structural health bridge monitoring allowing for wide, yet cost-effective, bridge stock coverage. The detection capability of the approach is tested in a laboratory setting for three different reversible proxy types of damage scenarios: changes in the support conditions (rotational restraint), additional damping, and an added mass at the midspan. A set of frequency features is used in conjunction with a support vector machine classifier on data measured from a passing vehicle at the wheel and suspension levels, and directly from the bridge structure for comparison. For each type of damage, four levels of severity were explored. The results show that for each damage type, the classification accuracy based on data measured from the passing vehicle is, on average, as good as or better than the classification accuracy based on data measured from the bridge. Classification accuracy showed a steady trend for low (1-1.75 m/s) and high vehicle speeds (2-2.75 m/s), with a decrease of about 7% for the latter. These results show promise towards a highly mobile structural health bridge monitoring system for wide and cost-effective bridge stock coverage.
Least squares estimator for the parameter of the fractional Ornstein-Uhlenbeck sheet
De la Cerda, Jorge Clarke,Tudor, Ciprian A. 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.3
We will study the least square estimator $\hat{\theta}_{T,S}$ for the drift parameter ${\theta}$ of the fractional Ornstein-Uhlenbeck sheet which is defined as the solution of the Langevin equation $$X_{t,s}=-{\theta}{\int}_{0}^{t}{{\int}_{0}^{s}\;X_{v,u}dvdu+B^{{\alpha},{\beta}}_{{t,s}}$$, $$(t,\;s)\;{\in}\;[0,\;T]{\times}[0,\;S]$$. driven by the fractional Brownian sheet $B^{{\alpha},{\beta}}$ with Hurst parameters ${\alpha}$, ${\beta}$ in ($\frac{1}{2}$, $\frac{5}{8}$). Using the properties of multiple Wiener-It$\hat{o}$ integrals we prove that the estimator is strongly consistent for the parameter ${\theta}$. In contrast to the one-dimensional case, the estimator $\hat{\theta}_{T,S}$ is not asymptotically normal.
Least squares estimator for the parameter of the fractional Ornstein–Uhlenbeck sheet
Jorge Clarke De la Cerda,Ciprian A. Tudor 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.3
We will study the least square estimator θT ,S for the drift parameter θ of the fractional Ornstein–Uhlenbeck sheet which is defined as the solution of the Langevin equation Xt,s = −θ t 0 s 0Xv,udvdu + Bα,βt,s , (t, s) ∈ [0, T ] × [0, S]. driven by the fractional Brownian sheet Bα,β with Hurst parameters α, β in ( 12 , 58). Using the properties of multiple Wiener–Itô integrals we prove that the estimator is strongly consistent for the parameter θ. In contrast to the one-dimensional case, the estimatorθT ,S is not asymptotically normal.
Monica Leon,Mauro Garibaldi,Fausto Virgen,Claudio Ramírez-Cerda,Salomon Cohen-Mussali 대한혈관외과학회 2020 Vascular Specialist International Vol.36 No.4
Differences in the common aortic arch branching pattern arise from abnormalembryological development. Aberrant origin of the right subclavian artery is themost common of these anomalies. We report the case of a 47-year-old female withprogressive dysphagia, found to have an aberrant right subclavian artery (ARSA)running posterior to the esophagus on computed tomography angiography. Shewas managed successfully with a hybrid procedure involving a right supraclavicularincision for ARSA ligation and subclavian to carotid transposition followed byendovascular closure of the ARSA origin.
J. P. Sanhueza,D. Rojas,J. García,M. F. Melendrez,E. Toledo,F. M. Castro Cerda,C. Montalba,A. F. Jaramillo 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9
In this study, three martensitic creep-resistant steels with 100, 90, and 70 ppm of boron were investigated. The experimentaldata obtained from isothermal aging and creep test at 650 °C were compared with the results of simulation conductedusing TC-PRISMA software. Tungsten was found to be the rate-controlling element in the coarsening of (Cr, Fe, W)23C6carbides; however, this result differed in terms of boron-containing steel. Several studies indicate that the low solubility ofboron in ferrite promotes boron enrichment in (Cr, Fe, W)23C6 carbide, thereby reducing its coarsening rate. However, thismechanism is not universally agreed upon. In the present study, a comparison between experimental and theoretical resultsrevealed that in boron-containing steels, the coarsening of (Cr, Fe, W)23C6 carbide is controlled probably by boron volumediffusion or by trans-interface diffusion.
( Roberto Monreal Robles ),( Hugo L Gallardo Blanco ),( Fernando J Lavalle Gonzalez ),( Ricardo M Cerda Flores ),( Pavel Carrillo Molina ),( Minerva G Martinez Cavazos ),( Laura E Martinez Garza ),( J 대한내과학회 2014 대한내과학회 추계학술발표논문집 Vol.2014 No.1
Background: Currently there are a growing number of individuals with type 2 diabetes (T2D) imposing a signifi cant public health burden due to disability and premature death. Diabetes is the most common cause of death in Mexico. It is estimated that 11.7 million Mexicans will have diabetes by the year 2025. The risk of developing T2D is determined by genetic and environmental factors. However, large differences in prevalence between ethnic groups exist and seem to depend on genetic factors. Nearly 40 different T2D susceptibility loci, mainly in Europeans have been identifi ed. The aim of this study was to identify susceptibility loci related to T2D in our population. Methods: We studied 128 SNPs in or near 42 genes, most of which had been replicated in other populations. A case-control association study comprising 186 controls, 211 early-onset T2D (diagnosed before 45 years of age) and 173 late-onset T2D individuals was conducted. Actually we preliminary reported the genotypifi cation analyses of 256 individuals. Results: Subjects with T2D independently of age at diagnosis have higher mass body index than controls (27.5 vs 25.7 kg/m2, P= <0.0001). The median age for early-onset T2D, late-onset T2D and controls individuals were 46, 61 and 62 years, respectively. Age at diagnosis for early-onset and late-onset T2D individuals was 35 and 52 years, respectively. The allelic variants of genes KCNJ11 (rs5219), LEPR (rs11208654), IGF2BP2 (rs4402960), VLDLR (rs2242103), KCNQ1 (rs2237892), RPTOR (rs12946115), SLC25A18 (rs1296819) show association with T2D in this preliminary analysis. These polymorphism previously mentioned affect directly or indirectly over insulin release and peripheral sensitivity. Conclusions: We found our population to have an important genetic predisposition to T2D. The associated susceptibility loci for T2D support the hypothesis that insulin release defects and peripheral resistance are the main mechanisms predisposing to T2D in Mexican population.
Alida Ospina-Orejarena,Ricardo Vera-Graziano,Maria Monica Castillo-Ortega,Juan Paulo Hinestroza,Mabel Rodriguez-Gonzalez,Laura Palomares-Aguilera,Marissa Morales-Moctezuma,Alfredo Maciel-Cerda 한국조직공학과 재생의학회 2016 조직공학과 재생의학 Vol.13 No.4
Increasing bioactivity and mechanical properties of polymers to produce more suitable scaffold for tissue engineering is a recurrent goal in the development of new biomedical materials. In this study, collagen-functionalized poly (lactic acid), PLA, was obtained by means of a simple grafting route, and electrospun scaffolds were produced to grow cells in vitro; their bioactivity was compared with scaffolds made of physical blends of PLA and collagen. Grafting was verified via nuclear magnetic resonance, attenuated total reflection-Fourier transform infrared and X-ray photoelectron spectroscopy. The cell adhesion performance of the scaffolds was studied using macrophages. Elastic modulus (74.7 megapascals) and tensile strength (3.0 megapascals) of the scaffold made from PLA grafted with collagen were substantially higher than the scaffolds made from physical blends of collagen and PLA: 32 and 2.16 megapascals, respectively, implying a more resistant material because of the chemical bond of the polypeptide to PLA. Besides, the fibers had more uniform diameter without defects. Scaffolds made from PLA grafted with collagen presented four-fold increase in cell adhesion than those of PLA blended with collagen. Furthermore, cell spreading within the scaffolds occurred only when collagen-functionalized poly (lactic acid) was used. These results open a new option for the easy tailoring of nanofiber-based scaffolds in three dimensions for tissue engineering.