An experimental study on creep deformation of thin-walled tubes under pure bending

Hsu, Chien-Min,Fan, Chun-Huei Techno-Press 2000 Structural Engineering and Mechanics, An Int'l Jou Vol.9 No.4

The creep deformation of pure bending (hold constant moment for a period of time) tests were conducted in this paper. Thin-walled tubes of 304 stainless steel were used in this investigation. The curvature-ovalization measurement apparatus, designed by Pan et al. (1998), was used for conducting the present experiments. It has been found that as soon as the creep deformation is started, the magnitudes of the tube curvature and ovalization of tube cross-section quickly increase. The magnitudes of the creep curvature and ovalization of tube cross-section increase fast with a higher hold moment than that with a lower one. Owing to the continuously increasing curvature during the creep deformation, the tube specimen buckles eventually.

Tamoxifen and the Risk of Parkinson’s Disease in Female Patients with Breast Cancer in Asian People: A Nationwide Population-Based Study

Chien-Tai Hong,Lung Chan,Chaur-Jong Hu,Chien-Min Lin,Chien-Yeh Hsu,Ming-Chin Lin 한국유방암학회 2017 Journal of breast cancer Vol.20 No.4

Purpose: Whether tamoxifen affects the risk of neurodegenerative disease is controversial. This nationwide population-based study investigated the risk of Parkinson’s disease (PD) associated with tamoxifen treatment in female patients with breast cancer using Taiwan’s National Health Insurance Research Database. Methods: A total of 5,185 and 5,592 female patients with breast cancer who did and did not, respectively, receive tamoxifen treatment between 2000 and 2009 were included in the study. Patients who subsequently developed PD were identified. A Cox proportional hazards model was used to compare the risk of PD between the aforementioned groups. Results: Tamoxifen did not significantly increase the crude rate of developing PD in female patients with breast cancer (tamoxifen group, 16/5,169; non-tamoxifen group, 11/5,581; p=0.246). Tamoxifen did not significantly increase the adjusted hazard ratio (aHR) for subsequently developing PD (aHR, 1.310; 95% confidence interval [CI], 0.605–2.837; p= 0.494). However, tamoxifen significantly increased the risk of PD among patients followed up for more than 6 years (aHR, 2.435; 95% CI, 1.008–5.882; p=0.048). Conclusion: Tamoxifen treatment may increase the risk of PD in Taiwanese female patients with breast cancer more than 6 years after the initiation of treatment.

Epidemiological trend in inflammatory bowel disease in Taiwan from 2001 to 2015: a nationwide population-based study

Hsu-Heng Yen,Meng-Tzu Weng,Chien-Chih Tung,Yu-Ting Wang,Yuan Ting Chang,Chin-Hao Chang,Ming-Jium Shieh,Jau-Min Wong,Shu-Chen Wei 대한장연구학회 2019 Intestinal Research Vol.17 No.1

Background/Aims: Incidences of inflammatory bowel disease (IBD), ulcerative colitis (UC), and Crohn’s disease (CD), havebeen increasing in Asia. In this study, we report the relevant clinical characteristics and determined the epidemiological trend ofIBD in Taiwan from 2001 to 2015. Methods: A retrospective study was conducted to analyze data recorded from January 2001through December 2015 in the registered database compiled by the National Health Insurance and provided by the Ministry ofHealth and Welfare, Taiwan. Results: A total of 3,806 patients with catastrophic IBD illness were registered from 2001 to 2015 inTaiwan (CD, 919; UC, 2,887). The crude incidence of CD increased from 0.17/100,000 in 2001 to 0.47/100,000 in 2015, whereasthat of UC increased from 0.54/100,000 in 2001 to 0.95/100,000 in 2015. The prevalence of CD increased from 0.6/100,000 in2001 to 3.9/100,000 in 2015, whereas that of UC increased from 2.1/100,000 in 2001 to 12.8/100,000 in 2015. The male-to-femaleratio in the study sample was 2.19 for CD and 1.62 for UC. The median age of those registered with CD was lower than that ofthose registered for UC: 38.86 and 44.86 years, respectively. A significantly greater increase in CD incidence rate was identifiedamong 20 to 39-year-old compared with other age groups. Conclusions: Using Taiwan’s nationwide insurance database, we determinedthat the number of patients with CD increased more rapidly during the study period than the number of patients withUC, especially among age 20 to 39-year-old, resulting in a decreased UC-to-CD ratio. (Intest Res 2019;17:54-62)

Learning Curve of ROSA ONE Spine System for Transpedicular Screw Placement

Bing-Hung Hsu,Heng-Wei Liu,Kha-Liang Lee,Ming-Chin Lin,Gao Chen,Jang Yu,Chiao-Ling Chen,I-Chang Su,Chien-Min Lin 대한척추신경외과학회 2022 Neurospine Vol.19 No.2

Objective: The study investigated our institutional learning curve for the ROSA ONE spine system (ROSA) based on ROSA usage time. Methods: ROSA was designed to provide high accuracy for spinal pedicle screw placement through a built-in tracking technique. This study was conducted from November 2018 to January 2021. The time taken to complete each step of the robotic workflow was recorded. Patient demographics, comorbidities, surgical indications, and number of screw placements were examined in subgroup analysis. The Curve Fitting-General package (a part of NCSS 2021 software) was used to fit a mathematical model to the learning curve. Patient demographics, imaging data, and surgical time were reviewed retrospectively. Results: A total of 167 patients who had undergone surgery were included. The mean total ROSA usage time was 107.1 ± 27.3 minutes. The estimated learning rate was 90.4%, and the largest slope change occurred close to the time of the 20th surgery. The observed overall learning trend in the 4-screw group could be attributed to screw planning. The presence of scoliosis (p = 0.73) or spondylolisthesis (p = 0.70) did not significantly influence the mean total time (TT) for all patients; however, the mean TT differed significantly (p < 0.01) among subgroups stratified by body mass index, screw number placement, and thoracic spine involvement. Conclusion: To the best of our knowledge, this is the first study to examine the learning curve for the various crucial steps of ROSA-guided pedicle screw placement. The indicative learning curve involved 20 patients who had undergone surgery.

Strain measurement of polymer materials by digital image correlation combined with finite-element analysis

Shun-Fa Hwang,Min-Chien Shen,Bin-Bin Hsu 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

Digital image correlation (DIC) can provide deformation information of a specimen by processing its two digital images captured beforeand after the deformation. In this study, a DIC method based on a modified coarse–fine iterative method is combined with finiteelementanalysis to obtain the strain and displacement data. This method is first verified with the use of an aluminum specimen underuniaxial testing. For polymer materials, polypropylene specimens with and without short glass fibers and polydimethylesiloxane specimenswith and without dyes are tested. Results indicate that the present method can capture the strains of these specimens even underhigh elongation and without artificial speckle pattern on their surfaces. Thus, the mechanical behavior of polymer materials can be characterizedand the effects of additional ingredients added to the materials can be assessed through the developed DIC method.

Viscoplastic analysis of thin-walled tubes under cyclic bending

Pan, Wen-Fung,Hsu, Chien-Min Techno-Press 1999 Structural Engineering and Mechanics, An Int'l Jou Vol.7 No.5

In this paper, different curvature-rates are controlled to highlight the characteristic of viscoplastic response in cyclic bending tests. The curvature-ovalization apparatus, which was designed by Pan et al. (1998), is used for conducting the curvature-controlled experiments on thin-walled tubular specimens for AISI 304 stainless steel under cyclic bending. The results reveals that the faster the curvature-rate implies, the fast degree of hardening of the metal tube. However, the ovalization of the tube cross-section increases when the curvature-rate increases.

Memory-dependent derivatives theory of thermo-viscoelasticity involving two-temperature

Shun-Fa Hwang,Min-Chien Shen,Bin-Bin Hsu 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

A new model of two-temperature generalized thermo-viscoelasticity theory based on memory-dependent derivative is constructed. Theequations of the new model are applied to one-dimensional problem of a half-space. The bounding surface is taken to be traction free andsubjected to a time dependent thermal shock. Laplace transforms technique is used. A direct approach is applied to obtain the exact formulasof heat flux, temperature, stresses, displacement and strain in the Laplace transform domain. Application is employed to our problemto get the solution in the complete form. The considered variables are presented graphically and discussions are made.

Endochronic simulation for the response of 1020 carbon steel tubes under symmetric and unsymmetric cyclic bending with or without external pressure

Kuo-Long Lee,Chien-Min Hsu,Chao-Yu Hung 국제구조공학회 2008 Steel and Composite Structures, An International J Vol.8 No.2

This paper presents the theoretical simulation of the response of 1020 carbon steel tubes subjected to symmetric and unsymmetric cyclic bending with or without external pressure by using the endochronic theory. Experimental data of 1020 carbon steel tubes tested by Corona and Kyriakides (1991) were used for evaluating the theoretical simulation. Several cases were considered in this study, they were symmetric bending without external pressure, symmetric bending with external pressure, unsymmetric bending without external pressure, and unsymmetric bending with external pressure. The responses of the moment-curvature, ovalization-curvature and ovalization-number of cycles with or without external pressure were discussed. It has been shown that the theoretical simulations of the responses correlate well with the experimental data.

Viscoplastic response and collapse of 316L stainless steel tubes under cyclic bending

Kao-Hua Chang,Shane-Rong Sheu,Chien-Min Hsu,Wen-Fung Pan 국제구조공학회 2005 Steel and Composite Structures, An International J Vol.5 No.5

This paper presents the experimental and theoretical results of the viscoplastic response and collapse of 316L stainless steel tubes subjected to cyclic bending. The tube bending machine and curvatureovalization measurement apparatus, which was designed by Pan et al. (1998), were used for conducting the cyclic curvature-controlled experiment. Three different curvature-rates were controlled to highlight the characteristic of viscoplastic response and collapse. Next, the endochronic theory and the principle of virtual work were used to simulate the viscoplastic response of 316L stainless steel tubes under cyclic bending. In addition, a proposed theoretical formulation (Lee and Pan 2001) was used to simulate the relationship between the controlled cyclic curvature and the number of cycles to produce buckling under cyclic bending at different curvature-rates (viscoplastic collapse). It has been shown that the theoretical simulations of the response and collapse correlate well with the experimental data.

Reduction of Physical Strength and Enhancement of Anti-Protein and Anti-Lipid Adsorption Abilities of Contact Lenses by Adding 2-Methacryloyloxyethyl Phosphorylcholine

Wan-Hsin Chang,Pei-Yi Liu,Chien-Ju Lu,Dai-En Lin,Min-Hsuan Lin,Yuan-Ting Jiang,Yuan-Hao Howard Hsu 한국고분자학회 2020 Macromolecular Research Vol.28 No.12

Biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC) can enhance the adsorption of water molecules and is therefore used for manufacturing contact lenses. This study investigated the mechanical strength, anti-protein deposition, and anti-lipid adsorption effects of MPC addition to contact lenses. Experimental contact lenses produced by copolymerizing multiple ratios of MPC to 2-hydroxyethyl methacrylate (HEMA) were analyzed. Atomic force microscopy revealed that MPC addition increased surface roughness. The anti-protein deposition and anti-lipid adsorption effects on poly(HEMA-MPC) polymers of various phosphorylcholine quantities were experimentally confirmed. The water content of the contact lenses was proportional to the MPC content in the polymer. The hydrated PC moiety of MPC drastically altered the network of the poly-HEMA polymer by inserting water molecules, which were trapped in the concave region of the surface. MPC addition had negative effects on all examined strength factors because of structural destabilization of the copolymer through water insertion. The anti-deposition effects of MPC were verified by examining the lysozyme and lipid adsorption abilities of the prepared contact lenses. Our results revealed that MPC enhanced interactions of the poly(HEMA-MPC) copolymer with water molecules; these interactions weakened the mechanical strength of the copolymer but markedly improved the anti-adsorption property of the biomolecules. The optimal proportion of HEMA–MPC for contact lenses is in the range 14.9%-28.5%.