Mechanical Error Analysis of Disk Cam Mechanisms with a Flat-Faced Follower

Chang Wen-Tung,Wu Long-Iong The Korean Society of Mechanical Engineers 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.3

By employing the concept of equivalent linkage, this paper presents an analytical method for analyzing the mechanical errors of disk cam mechanisms with a flat-faced follower. The resulting error equations do not really involve the location of the curvature center of the cam profile, and locating the curvature center of the cam profile is not essential. The resulting errors are significantly affected by the pressure angle, and the smaller pressure angle will result in the smaller mechanical error. In the worst case, owing to the joined effects of various design parameters, the accuracy of the follower motion may degrade considerably. For the oscillating follower case, all acceleration error functions have a sudden change at every beginning and at every end of the motion even though the theoretical follower displacement is cycloidal motion.

Efficacy of Epigallocatechin-3-Gallate and Amla (Emblica officinalis) Extract for the Treatment of Diabetic-Uremic Patients

Tung-Sheng Chen,Show-Yih Liou,Hsi-Chin Wu,Fuu-Jen Tsai,Chang-Hai Tsai,Chih-Yang Huang,Yen-Lin Chang 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.7

Uremic patients with diabetes suffer from high levels of oxidative stress due to regular hemodialysis therapy (neutrophil activation induced by hemo-incompatibility between the hemodialyser and blood) and complications associated with diabetes. Several plasma biomarkers were screened in 13 uremic diabetic patients after receiving the mixture of (–)-epigallocatechin gallate (EGCG), a major component of green tea extract, and Amla extract (AE), from Emblica officinalis, the Indian gooseberry, for 3 months. We found that oral administration of a 1:1 mixture of EGCG and AE for 3 months significantly improved antioxidant defense as well as diabetic and atherogenic indices in uremic patients with diabetes. Furthermore, no significant changes in hepatic function, renal function, or inflammatory responses were observed. These results suggest that a 1:1 combination of EGCG and AE is a safe and effective treatment for uremic patients with diabetes.

Mechanical Error Analysis of Disk Cam Mechanisms with a Flat-Faced Follower

Wen-Tung Chang,Long-Iong Wu 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.3

By employing the concept of equivalent linkage, this paper presents an analytical method for analyzing the mechanical errors of disk cam mechanisms with a flat-faced follower. The resulting error equations do not really involve the location of the curvature center of the cam profile, and locating the curvature center of the cam profile is not essential. The resulting errors are significantly affected by the pressure angle, and the smaller pressure angle will result in the smaller mechanical error. In the worst case, owing to the joined effects of various design parameters, the accuracy of the follower motion may degrade considerably. For the oscillating follower case, all acceleration error functions have a sudden change at every beginning and at every end of the motion even though the theoretical follower displacement is cycloidal motion.

2H-Silicon Carbide Epitaxial Growth on c-Plane Sapphire Substrate Using an AlN Buffer Layer and Effects of Surface Pre-Treatments

Tien-Tung Luong,Binh Tinh Tran,Yen-Teng Ho,Ting-Wei Wei,Yue-Han Wu,Tzu-Chun Yen,Lin-Lung Wei,Jer-Shen Maa,Edward Yi Chang 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.3

The effects of surface pre-treatments and the role of an AlN buffer layer for 2H-SiC growth on c-plane sapphire substrates by thermal CVD are investigated. While the crystallinity of SiC directly grown on sapphire substrate always degrades with a hydrogen pre-treatment but improves by optimizing carbonization, the crystallinity of SiC grown on sapphire substrate using an AlN buffer grown by MOCVD improves with sufficient time of exposure to the H pre-treatment but always deteriorates with carbonization. Detailed microstructural analysis by phi-scan x-ray diffraction reveals that SiC film grown on sapphire substrate consists of crystalline domains with two different crystallographic orientations which are rotated relative to each other along the [111] axis by 60°. A highly oriented hexagonal 2H-SiC film is obtained on low-cost c-plane sapphire substrate by using an AlN buffer. 2H-SiC is unambiguously determined not only by phi-scan x-ray diffraction but also by high-resolution transmission electron microscopy. The growth relationship between 2HSiC and 2H-AlN are coherent due to the favorable bonding of C and Al between SiC and AlN.

Impact of Obesity on a Chinese Population with Erosive Esophagitis and Barrett`s Esophagus

( Shou-wu Lee ),( Han-chung Lien ),( Teng-yu Lee ),( Chun-fang Tung ),( Hong-zen Yeh ),( Chi-sen Chang ) 대한간학회 2017 Gut and Liver Vol.11 No.3

Background/Aims: The aim of this study was to investigate the associations between obesity and erosive esophagitis (EE) or Barrett`s esophagus (BE) in a Chinese population. Methods: Data from subjects were retrospectively collected from 2006 to 2009. Individuals with BE were identified and age- and sex-matched at a 1:2 ratio with normal esophagocardial junction and EE patients. The subjects were stratified into two groups: the normal weight group and overweight/ obesity group (body mass index ≥25 mg/m2) or the normal waist group and abdominal obesity group (waist circumference ≥90 cm for men and ≥80 cm for women). Results: Overall, 45%, 72%, and 52% were overweight/obese and 23%, 65%, and 18% had abdominal obesity in the normal, EE, and BE groups, respectively. Positive associations were identified between EE and overweight/obesity (odds ratio [OR], 3.14; 95% confidence interval [CI], 1.75 to 5.66) and abdominal obesity (OR, 6.22; 95% CI, 3.34 to 11.57); however, the associations were nonsignificant between BE and overweight/obesity (OR, 1.32; 95% CI, 0.67 to 2.61) or abdominal obesity (OR, 0.73; 95% CI, 0.31 to 1.73). Female BE patients had a significantly increased rate of being overweight/obese. Conclusions: Obesity is a contributing factor in EE. The association of BE and obesity was not significant, with the exception of female BE cases. (Gut Liver 2017;11:377-382)

BRONCHOPULMONARY SEQUESTRATION ASSOCIATED WITH ASPERGILLOMA : A CASE REPORT

Wang, Tung Heng,Hwang, Jhi Jhu,Wu, Chung Chieng,Chen, Chang Yi 대한핵의학회 1984 핵의학 분자영상 Vol.18 No.1

An Intelligent System for Business Data Mining

Shian Chang Huang,Tung Kuang Wu,Nan Yu Wang People&Global Business Association 2017 Global Business and Finance Review Vol.22 No.2

Mining high-dimensional business data is a challenging problem. Particularly in bankruptcy predictions, we need to analyze large amounts of information from financial statements and stock markets. This paper proposes a new strategy to deal with the problem. Because of the highly correlation among financial information, this study employed a technique called generalized discriminant analysis (GDA) to identify important features and reduce the data dimension. GDA is a nonlinear discriminant analysis using kernel function operator. It’s easy to deal with a wide class of nonlinearity in financial data, and can reduce the computational loading of subsequent prediction classifier. Due to the promising success of kernel machines in many applications, this study utilized a generalized multiple kernel machine (GMKM) to serve as the predictor. Combining the strengths of GDA and GMKM, our system robustly outperforms traditional prediction systems.

Calculating actual profiles of conjugate disk cams by means of conjugate variation measurement

Wen-Tung Chang,Long-Iong Wu 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.12

For an assembled conjugate cam mechanism with two separate oscillating roller followers serving as a conjugation measuring fixture,when the cams rotate, the variation of the subtending angle between the two follower arms can indicate the variation of the cam profile errors. The profile errors of the assembled conjugate disk cams can be indirectly calculated by means of the conjugate variation measurement and the inverse conjugate variation analysis. That is, if a pair of master conjugate cams with known profile errors is available, by means of the measured subtending angle variations of the follower arms induced by a pair of assembled conjugate cams that consists of one master cam and the other being the inspected cam, then the actual profile of the inspected cam can be calculated by applying the inverse conjugate variation analysis. In order to verify the presented concept, experiments meant to calculate the profile errors of a pair of machined conjugate cams were conducted to compare with the measuring results obtained by using a coordinate measuring machine. The experimental results showed that the calculated cam profiles were well consistent with those of the measured ones. The presented method can be an effective alternative means for examining profile errors of assembled conjugate disk cams and could be useful for the quality control in mass production of conjugate cams.

The kinematic design of a planar-cam type pick-and-place device

Wen-Tung Chang,Long-Iong Wu,Chun-Hsien Liu 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.12

The planar-cam type pick-and-place device can clearly and effectively achieve the desired curvilinear motion of its end effector, and it can be designed and fabricated easily. By employing the concept of velocity instant center, the cam profiles, the paths of cutters, the pressure angles and the radii of curvature of the dual cams of the planar-cam type pickand- place device can be expressed parametrically. The cam profiles may have concave portions, and each minimum radius of curvature of the concave portion of the dual cam profiles is the upper bound of the grinding-wheel radius that may not cause undercutting.

Synthesis of mesoporous SiO2 xerogel/chitosan mixed-matrix membranes for butanol dehydration

Yi-Feng Lin,Chang-Yu Wu,Ting-Yu Liu,Kun-Yi Andrew Lin,Kuo-Lun Tung,Tsair-Wang Chung 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-

Novel mesoporous SiO2 xerogel/chitosan (CS) mixed-matrix membranes (MMMs) were successfully prepared by incorporating sol–gel synthesized SiO2 xerogels into glutaraldehyde (GA) cross-linked CS membranes. The effects of the SiO2 doping amount and the feed temperature on the performance of the separation of butanol and water was also investigated in this study. The 0.25 wt% SiO2 xerogel/CS MMMs possessed the best pervaporation performance and the largest PSI value of 1102 kg/m2h with a permeate flux of 736 g/m2h (Permeability of 3.25 × 10−5 g m m−2 h −1 Pa−1) and a separation factor of 1498 at a feed temperature of 50 °C. This PSI value is not only comparable but also exceeds that of other membranes reported in the literature. The separation factor and the flux of the SiO2 xerogel/CS MMMs in this study clearly exceed the upper limit of the previously reported MMMs. As a result, the as-prepared novel SiO2 xerogel/CS MMMs showed an improved performance during the butanol and water separation process, which raises the possibility of future pervaporation applications using this novel SiO2 xerogel/CS MMMs.