Uniaxial Compression Properties and Compression Fatigue Performance of Selective Laser Melted Ti–6Al–4V Cellular Structure

Ming‑Wei Wu,Jhewn‑Kuang Chen,Mo‑Kai Tsai,Pei Wang,Tien‑Lin Cheng,Bo‑Huan Lin,Po‑Hsing Chiang,Annadurai Dhinakar 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.1

The selective laser melted (SLM) Ti–6Al–4V cellular solid is a promising material in biomedical and other applications. The mechanical properties of the SLM Ti–6Al–4V cellular material are predominantly controlled by the design of the cellular structure. The objective of this study was to investigate the uniaxial compressive properties and compressive fatigueperformance of the SLM Ti–6Al–4V cellular solid with a new cuboctahedron unit cell reinforced by four diagonal strutsand two horizontal struts along the X and Y axes. The infuences of hot isostatic pressing (HIP) on the various mechanicalproperties were also examined. The results showed a smoother stress–strain curve and fewer stress oscillations in the HIPspecimen than in the SLM specimen. The HIP process slightly decreased the yield strength of the SLM sample from 55 to52 MPa. Under uniaxial compressive stress, the SLM and HIP specimens exhibited layer-by-layer fracture and diagonalshear fracture, respectively. Furthermore, the HIP treatment signifcantly increased the fatigue performance and improved thefatigue endurance ratio at 106cycles from 0.15 to 0.35. The HIP treatment contributed to several positive efects, includingphase transformation from brittle α′ to α + β, the elimination of strut porosity and residual stress, an increase in lath size,and a better combination of strength and ductility, thereby improving the fatigue performance. The efects of stress mode onthe fracture mechanism were also clarifed using in situ observation in combination with digital image correlation.

Temperature control scheme using hot-gas bypass for a machine tool oil cooler

Wei-Ming Chiang,Win-Jet Luo,Fu Jen Wang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3

Accurate temperature control that addresses heat generation is crucial given the development of high-accuracy high-speed machining process. Heat generation leads to a thermal error of machine tools. Therefore, developing high-accuracy machining without appropriate temperature control scheme is challenging. Machine tool coolers for forced convection cooling can effectively control heat generation. However, temperature control accuracy cannot be achieved because the temperature control scheme for machine tool oil cooler encounters nonlinear and time-varying problems with time delay characteristic. This study presents a novel temperature control scheme, namely, Proportional–integral–derivative (PID) control logic based on Smith predictive method. MATLAB simulation software was utilized to determine the specifications of outlet temperature control using hot-gas bypass scheme of high-precision oil cooler with refrigerant R-32. Simulation results revealed that the proposed control scheme present better temperature control accuracy than the traditional PID control. The proposed control scheme can also effectively solve the abovementioned problems through on-site experimental results. The steadystate error of the oil outlet temperature of the high-precision-type machine tool oil cooler can be controlled within 0.1 °C by using the proposed control hot-gas bypass scheme.

An experiment investigation of temperature control performance for machine tool oil coolers with hot-gas bypass temperature control scheme and inverter temperature control scheme

Wei-Ming Chiang,Fu Jen Wang,Kusnandar 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.2

Following the machine tool with demands of high-speed, high-precision machining and multi-axis, the heat generation of machine tool will lead to thermo growth of spindle, thermal error, etc. Therefore, the machine tool oil cooler has been frequently adopted for thermal management of heat generation for machine tool. However, it will be quite challenging to develop high-precision machining without suitable temperature control scheme. And, the machine tool oil cooler with on-off control is difficult to control the oil temperature accurately. Therefore, in this paper, the machine tool oil cooler with hot-gas bypass temperature control scheme and inverter temperature control scheme based on the PID control logic have been proposed to solve the oil temperature control problem for machine tool oil cooler. Furthermore, the temperature control performance (i.e. thermo growth of spindle, oil temperature control accuracy, and EER) of hot-gas bypass temperature control scheme and inverter temperature control scheme has been compared by means of experiment. The experimental results shows that the inlet oil temperature control accuracy can be maintained ±0.2 °C during spindle operation by using the hot-gas bypass temperature control scheme (HGB cooler) and inverter temperature control scheme (INV cooler). Furthermore, the thermo growth of spindle of HGB cooler is about 14 % smaller than the INV cooler because of hot-gas bypass temperature control scheme with thermal compensation function. However, the total power consumption of HGB cooler is about 0.18 kW higher than the INV cooler. Hence, the energy efficiency ratio (EER) of INV cooler reveals about 10.9 % higher than the HGB cooler at steady state. Furthermore, when oil flow rate declined to about half, the temperature difference between initial and final steady state temperature of the spindle is increased around 94.3 %, and the thermo growth of spindle is increased 58.7 %.

Analytical and experimental research on wind-induced vibration in high-rise buildings with tuned liquid column dampers

Liu, Ming-Yi,Chiang, Wei-Ling,Chu, Chia-Ren,Lin, Shih-Sheng Techno-Press 2003 Wind and Structures, An International Journal (WAS Vol.6 No.1

In recent years, high-strength, light-weight materials have been widely used in the construction of high-rise buildings. Such structures generally have flexible, low-damping characteristics. Consequently, wind-induced oscillation greatly affects the structural safety and the comfort of the building's occupants. In this research, wind tunnel experiments were carried out to study the wind-induced vibration of a building with a tuned liquid column damper (TLCD). Then, a model for predicting the aerodynamic response in the across-wind direction was generated. Finally, a computing procedure was developed for the analytical modeling of the structural oscillation in a building with a TLCD under the wind load. The model agrees substantially with the experimental results. Therefore, it may be used to accurately calculate the structural response. Results from this investigation show that the TLCD is more advantageous for reducing the across-wind vibration than the along-wind oscillation. When the across-wind aerodynamic effects are considered, the TLCD more effectively controls the aerodynamic response. Moreover, it is also more useful in suppressing the acceleration than the displacement in biaxial directions. As s result, TLCDs are effective devices for reducing the wind-induced vibration in buildings. Parametric studies have also been conducted to evaluate the effectiveness of the TLCD in suppressing the structural oscillation. This study may help engineers to more correctly predict the aerodynamic response of high-rise buildings as well as select the most appropriate TLCDs for reducing the structural vibration under the wind load. It may also improve the understanding of wind-structure interactions and wind resistant designs for high-rise buildings.

The Technical Benefits of Future GNSS for Taiwan

Kai-Wei Chiang,Ming Yang,Meng-Lun Tsai,Yao-Yun Chang,Chi-Kuang Chu 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.2 No.-

The next decade promises drastic improvements and additions to global navigation satellite systems (GNSS). Plans for GPS modernization include a civilian code measurement on the L2 frequency and a new L5 signal at 1176.45MHz. Current speculations indicate that a fully operational constellation with these improvements could be available by 2013. Simultaneously, the Galileo Joint Undertaking is in the development and validation stages of introducing a parallel GNSS called Galileo. Galileo will also transmit freely available satellite navigation signals on three frequencies and is scheduled to be fully operational as early as 2008. In other words, a dual system receiver (e.g., GPS+GALILEO) for general users can access six civil frequencies transmitted by at least fifty eights navigation satellites in space. The advent of GALILEO and the modernization of GPS raise a lot of attention to the study of the compatibility and interoperability of the two systems. A number of performance analyses have been conducted in a global scale with respect to availability, reliability, accuracy and integrity in different simulated scenarios (such as open sky and urban canyons) for the two systems individually and when integrated. Therefore, the scope of this article aims at providing the technical benefits analysis for Taiwan specifically in terms of the performance indices mentioned above in a local scale, especially in typical urban canyon scenarios. The conclusions gained by this study will be applied by the Land Survey Bureau of Taiwanese as the guideline for developing future GNSS tracking facilities and dual GNSS processing module for precise surveying applications in static and kinematic modes.

Enhanced Performance of Pseudo-Bilayer Organic Photovoltaic Devices via Small Molecule Doping

Syu, Yu-Wei,Huang, Peng-Yi,Li, Husan-De,Hsu, Ching-Ling,Chiu, Kuan-Cheng,Kim, Choongik,Chen, Ming-Chou,Chao, Yu-Chiang American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.19

<P>Controlling both the film crystallinity of the active layer for better charge transport and the interdiffusion between donor and acceptor materials for optimal bicontinuous networks is essential in producing pseudo-bilayer polymer solar cells. In this work, we investigated the influence of a doping solution-processable small molecule with high carrier mobility, 5,11-bis(triethylsilylethynyl) anthradithiophene (TES-ADT), on the performance of pseudo-bilayer polymer solar cells made of an underlayer of poly(3-hexylthiophene) (P3HT) and an upper layer of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). By analysis of the X-ray diffraction and UV–vis absorbance spectra of P3HT:TES-ADT blend films it was demonstrated that the film crystallinity was enhanced by TES-ADT doping in the P3HT underlayer. The hole mobility extracted from the current density–voltage curves of hole-only devices based on P3HT:TES-ADT demonstrated an optimized value with proper TES-ADT doping and thermal annealing. An intermixed photoactive layer was observed for the annealed device, indicating the occurrence of interdiffusion with a large interfacial area. With improved film crystallinity and interdiffusion, the optimal device performance was obtained when 5% TES-ADT was blended with P3HT and a thermal annealing treatment at 150 °C for 1 min was conducted. At that optimal condition, the mean crystallite size was increased by 35%, and hence the enhancement of 8% and 14% in power conversion efficiency and short-circuit current density was observed, respectively.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-19/jp502331x/production/images/medium/jp-2014-02331x_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp502331x'>ACS Electronic Supporting Info</A></P>

The Antiproliferation Activity of Ganoderma formosanum Extracts on Prostate Cancer Cells

( Cheng-yen Chiang ),( Kai-di Hsu ),( Yen-yi Lin ),( Chang-wei Hsieh ),( Jui-ming Liu ),( Tze-ying Lu ),( Kuan-chen Cheng ) 한국균학회 2020 Mycobiology Vol.48 No.3

Androgen-independent prostate cancer accounts for mortality in the world. In this study, various extracts of a medical fungus dubbed Ganoderma formosanum were screened for inhibition of DU145 cells, an androgen-independent prostate cancer cell line. Results demonstrated that both hexane (GF-EH) and butanol (GF-EB) fraction of G. formosanum ethanol extract inhibited DU145 cell viability in a dose-dependent manner. GF-EH induced cell-cycle arrest in G1 phase of DU145 cells via downregulation of cyclin E2 protein expression. In addition, GF-EB triggered extrinsic apoptosis of DU145 cells by activating caspase 3 gene expression resulting in programed cell death. Above all, both GF-EH and GF-EB show lower toxicity to normal human fibroblast cell line compared to DU145 cell, implying that they possess specific drug action on cancer cells. This study provides a molecular basis of G. formosanum extract as a potential ingredient for treatment of androgen-independent prostate cancer.

Case Reports : Scaly Ear Rash as the Herald of a Young Girl with Juvenile Systemic Lupus Erythematosus

( Ching Fu Huang ),( Wei Ming Wang ),( Chien Ping Chiang ) 대한피부과학회 2011 Annals of Dermatology Vol.23 No.3s

Juvenile systemic lupus erythematosus (JSLE) is an autoimmune- mediated multiorgan disease. The cutaneous manifestation is one of the most common initial presentations in JSLE. A typical lesion is a facial malar rash, but a patient may sometimes present with nonclassical lesions. Herein, we report two cases of JSLE with similar persistent scaly ear rashes as the heralding cutaneous symptom preceding systemic symptoms. Identifying this atypical and underestimated cutaneous rash in juvenile patients might help the clinician make the correct diagnosis and provide earlier intervention, which may help prevent disease progression. (Ann Dermatol 23(S3) S333~S337, 2011)

Comparison of Transforming Growth Factor-Beta1 and Lovastatin on Differentiating Mesenchymal Stem Cells toward Nucleus Pulposus-like Phenotype: An In Vitro Cell Culture Study

Shu-Hua Yang,Kai-Chiang Yang,Chih-Wei Chen,Ting-Chun Huang,Yuanhui Sun,Ming-Hsiao Hu 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.5

Study Design: In vitro cell culture study. Purpose: This study aims to investigate the impact of transforming growth factor-beta1 (TGF-β1) and lovastatin on differentiating human mesenchymal stem cells (MSCs) toward nucleus pulposus (NP)-like phenotype. Overview of Literature: MSCs offer a cell source to the cell-based therapy for intervertebral disc degeneration. TGF-β1 is used to induce MSCs to differentiate into NP-like cells; however, an undesired expression of collagen type I has been reported. Statins reportedly stimulate expression of bone morphogenetic protein-2 (BMP-2) and promote the chondrogenic phenotype to NP cells. However, the effects of statins with or without TGF-β1 on the differentiation of MSCs into NP-like cells remain unclear. Methods: Human MSCs were treated with TGF-β1 alone, lovastatin alone, and simultaneous or sequential treatment with TGF-β1 and lovastatin. After the proposed stimulation, the total RNA was extracted to assess the expression profile of NP cells-specific genes. Hematoxylin–eosin staining was used for examining the microscopic morphology. Furthermore, we detected the syntheses of S-100 protein, aggrecan , and collagen type II in the extracellular matrix using immunohistochemical staining. Results: Simultaneous or sequential treatment of TGF-β1 and lovastatin could further augment the BMP-2 overexpression compared with lovastatin-alone treatment. However, the mRNA expression of aggrecan and collagen type II was not compatible with the expression level of BMP-2 . Immunohistochemical studies revealed compatible production of aggrecan, collagen type II , and S-100 protein in all three groups treated with lovastatin. Cells in groups treated with lovastatin were less populated than that in the group treated with TGF-β1 alone. Conclusions: This study demonstrates a promising role of lovastatin in inducing human MSCs into NP-like cells. However, further optimization of cell density before lovastatin treatment, treatment duration, and combination with TGF-β1 are warranted to attain better stimulatory effects.

Scaly Ear Rash as the Herald of a Young Girl with Juvenile Systemic Lupus Erythematosus

Ching-Fu Huang,Wei-Ming Wang,Chien-Ping Chiang 대한피부과학회 2011 Annals of Dermatology Vol.23 No.-

Juvenile systemic lupus erythematosus (JSLE) is an autoimmune-mediated multiorgan disease. The cutaneous manifestation is one of the most common initial presentations in JSLE. A typical lesion is a facial malar rash, but a patient may sometimes present with nonclassical lesions. Herein, we report two cases of JSLE with similar persistent scaly ear rashes as the heralding cutaneous symptom preceding systemic symptoms. Identifying this atypical and underestimated cutaneous rash in juvenile patients might help the clinician make the correct diagnosis and provide earlier intervention, which may help prevent disease progression. (Ann Dermatol 23(S3) S333∼S337, 2011)