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Super-Eddington Accretion in the <i>WISE</i>-selected Extremely Luminous Infrared Galaxy W2246−0526
Tsai, Chao-Wei,Eisenhardt, Peter R. M.,Jun, Hyunsung D.,Wu, Jingwen,Assef, Roberto J.,Blain, Andrew W.,Dí,az-Santos, Tanio,Jones, Suzy F.,Stern, Daniel,Wright, Edward L.,Yeh, Sherry C. C. American Astronomical Society 2018 The Astrophysical journal Vol.868 No.1
Chao-Tsai Huang,Jia-Hao Chu,Wei-Wen Fu,Chia Hsu,Sheng-Jye Hwang 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.3
During the past two centuries, due to too fast growth of the human population, the pollution made by human has seriously impacts on our environment, particularly, for the CO2 emission. To diminish the CO2 emission problem, one of the effective solutions is applying lightweight material, such as the fiber-reinforced plastics (FRP), to replace metal in the manufacturing of transportation vehicles. However, since the reinforced function of the fibers inside plastic matrix is very complex, it is not easy to be visualized and managed. Specifically, the connection from microstructures of the fibers to the physical properties of the final product is far from our understanding. In this study, we have proposed a benchmark with three standard specimens based on ASTM D638 with different gate designs. This system is used to study the fiber microstructures and associated mechanical properties using numerical simulation and experimental studies. Results showed that the tensile properties (including tensile modulus and tensile stress) of all three ASTM standard specimens can be improved significantly in the appearance of the fibers. Moreover, the tensile properties variation of the finished parts associated with the microstructures of the short fibers based on the gate design have been also investigated. Specifically, the tensile modulus and the strength of the Model I are greater than that of Model II, while Model III is much less than others because of its double gate effect. The reason why the tensile modulus and the strength of the Model I is greater than that of Model II is due to some entrance effect. That entrance effect will further provide flow-induced fiber orientation to melt and then enhance the tensile properties of Model I. To confirm the observation, a series simulation and experimental studies have been performed. Specifically, the fiber orientation distribution is predicted using CAE, and verified using micro-CT scan and image analysis by Avizo software. Hence, the correlation from fiber microstructure feature (particularly in fiber orientation) to tensile modulus and tensile stress for fiber reinforced thermoplastic (FRP) in injection molding process can be validated.
Chao-Tsai Huang,Jun-Zheng Wang,Cheng-Hong Lai,Sheng-Jye Hwang,Po-Wei Huang,Hsin-Shu Peng 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.4
Fiber reinforced thermoplastics (FRP) have been widely used in automotive industry. However, how does the flow-fiber coupling effect influence the micro fiber orientation and further affect the geometrical shrinkage of the final part that is not fully understood yet. In this study, a complex center-gated plate has been applied to study the influence of the flow-fiber coupling effect on the fiber orientation variation and the geometrical change through numerical simulation. Then the practical verification through the micro-computed tomography (micro-CT) and image processing technology was carried out. Results show that in the presence of the flow-fiber coupling the required spruce pressure will be higher compared to no coupling case. In addition, the melt flow front pattern will be changed from “convex-flat” to “convex-concave” under the influence of this coupling. Moreover, in the presence of the flow-fiber coupling effect, the wider core width for fiber orientation tensor in the flow direction (A11) can be obtained from upstream to downstream regions for the same model. However, in the downstream region (i.e. in the FR), the flow-fiber coupling effect is more significantly due to the action of less shear rate in that region. Finally, through the measurement of the left–right asymmetrical shape of the FR for Model I (or Model II), the reason is that the flow-fiber coupling effect will switch the fiber orientation from the flow direction (A11) dominate to the cross-flow direction (A22) dominate. This asymmetrical fiber orientation distribution will further create that asymmetrical shrinkage shape of final part. The correlation between fiber orientation and geometrical shrinkage can be achieved.
Tzu-Chau Chen,Chao-Tsai Huang,Yan-Chen Chiu,Wei-Da Wang,Cheng-Li Hsu,Chen-Yang Lin,Lung-Wen Kao 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
Runner system plays a very important role in injection molding process. A quality runner design is helpful in improving product qualities and saving material. However, traditional cold runner systems have certain inherent issues. Moreover, poor product cosmetics are commonly seen with the use of traditional cold runners. As a result, hot runner technology has been widely applied. On the other hand, It has been one of the green molding solutions for material/energy saving and clean environments. But the mechanism behind the hot runner system is too complicated to be fully understood. There exist some critical issues currently. As a result, the simulation technolgy is highly needed to examine hot runner designs before the real manufacturing. Through simulation analyses, designers and manufafctuers are able to catch the potential issues on their hot runner systems and revise their designs. Hot runner simulation technology helps with the investigations into the behavior in hot runner system. In this paper, a true 3D numerical method is proposed and applied to investigate the temperature behavior in a real hot runner system for PC material. The experiment is conducted and the simulating result is compared with that from the experiment for the validation purpose.
Chen, How-Ji,Tsai, Wen-Po,Tang, Chao-Wei,Liu, Te-Hung Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.39 No.6
We have developed a lightweight aggregate (LWA) concrete made by expanding fine sediments dredged from the Shihmen Reservoir (Taiwan) with high heat. In this study, the performance of the concrete and of prestressed concrete beams made of the sedimentary LWA were tested and compared with those made of normal-weight concrete (NC). The test results show that the lightweight concrete (LWAC) exhibited comparable time-dependent properties (i.e., compressive strength, elastic modulus, drying shrinkage, and creep) as compared with the NC samples. In addition, the LWAC beams exhibited a smaller percentage of prestress loss compared with the NC beams. Moreover, on average, the LWAC beams could resist loading up to 96% of that of the NC beams, and the experimental strengths were greater than the nominal strengths calculated by the ACI Code method. This investigation thus established that sedimentary LWA can be recommended for structural concrete applications.
Chen, How-Ji,Liu, Te-Hung,Tang, Chao-Wei,Tsai, Wen-Po Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.6
The objective of this study was to experimentally investigate the bond-related tension stiffening behavior of flexural reinforced concrete (RC) beams made with lightweight aggregate concrete (LWAC) under various high-cycle fatigue loading conditions. Based on strain measurements of tensile steel in the RC beams, fatigue-induced degradation of tension stiffening effects was evaluated and was, compared to reinforced normal weight concrete (NWC) beams with equal concrete compressive strengths (40 MPa). According to applied load-mean steel strain relationships, the mean steel strain that developed under loading cycles was divided into elastic and plastic strain components. The experimental results showed that, in the high-cycle fatigue regime, the tension stiffening behavior of LWAC beams was different from that of NWC beams; LWAC beams had a lesser reduction in tension stiffening due to a better bond between steel and concrete. This was reflected in the stability of the elastic mean steel strains and in the higher degree of local plasticity that developed at the primary flexural cracks.
( Chun-chi Lin ),( Shu-chen Wei ),( Been-ren Lin ),( Wen-sy-tsai ),( Jinn-shiun Chen ),( Tzu-chi Hsu ),( Wei-chen Lin ),( Tien-yu Huang ),( Te-hsin Chao ),( Hung-hsin Lin ),( Jau-min Wong ),( Jen-kou 대한장연구학회 2016 Intestinal Research Vol.14 No.3
Background/Aims: With the recent progress in medical treatment, surgery still plays a necessary and important role in treating ulcerative colitis (UC) patients. In this study, we analyzed the surgical results and outcomes of UC in Taiwan in the recent 20 years, via a multi-center study through the collaboration of Taiwan Society of IBD. Methods: A retrospective analysis of surgery data of UC patients from January 1, 1995, through December 31, 2014, in 6 Taiwan major medical centers was conducted. The patients’ demographic data, indications for surgery, and outcome details were recorded and analyzed. Results: The data of 87 UC patients who received surgical treatment were recorded. The median post-operative follow-up duration was 51.1 months and ranged from 0.4 to 300 months. The mean age at UC diagnosis was 45.3±16.0 years and that at operation was 48.5±15.2 years. The 3 leading indications for surgical intervention were uncontrolled bleeding (16.1%), perforation (13.8%), and intractability (12.6%). In total, 27.6% of surgeries were performed in an emergency setting. Total or subtotal colectomy with rectal preservation (41.4%) was the most common operation. There were 6 mortalities, all due to sepsis. Emergency operation and low pre-operative albumin level were significantly associated with poor survival (P =0.013 and 0.034, respectively). Conclusions: In the past 20 years, there was no significant change in the indications for surgery in UC patients. Emergency surgeries and low pre-operative albumin level were associated with poor survival. Therefore, an optimal timing of elective surgery for people with poorly controlled UC is paramount.
How-Ji Chen,Te-Hung Liu,Chao-Wei Tang,Wen-Po Tsai 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.6
The objective of this study was to experimentally investigate the bond-related tension stiffening behavior of flexural reinforced concrete (RC) beams made with lightweight aggregate concrete (LWAC) under various high-cycle fatigue loading conditions. Based on strain measurements of tensile steel in the RC beams, fatigue-induced degradation of tension stiffening effects was evaluated and was, compared to reinforced normal weight concrete (NWC) beams with equal concrete compressive strengths (40 MPa). According to applied load-mean steel strain relationships, the mean steel strain that developed under loading cycles was divided into elastic and plastic strain components. The experimental results showed that, in the high-cycle fatigue regime, the tension stiffening behavior of LWAC beams was different from that of NWC beams; LWAC beams had a lesser reduction in tension stiffening due to a better bond between steel and concrete. This was reflected in the stability of the elastic mean steel strains and in the higher degree of local plasticity that developed at the primary flexural cracks.