Shih-Hsuan Chiu, Cheng-Lung Wu, Shun-Ying Gan, Kun-Ting Chen, Yi-Ming Wang, Sheng-Hong Pong and Hitoshi Takagi
The purpose of this study is to increase the thermal and mechanical properties of the photopolymer by filling with the copper powder for the application of rapid tooling.
Abstract
Purpose
The purpose of this study is to increase the thermal and mechanical properties of the photopolymer by filling with the copper powder for the application of rapid tooling.
Design/methodology/approach
In this study, the photopolymer is filled with the different loading of copper powder for investigating the thermal and mechanical properties of the copper/photopolymer composite. The thermal properties of the copper/photopolymer composite are characterized with the degradation temperature and with the thermal conductivity. The mechanical properties of copper/photopolymer composite are performed with the tensile strength and hardness testing. Moreover, the copper/photopolymer composite is imaged by using a scanning electron microscopic with energy dispersive spectroscopy.
Findings
The tensile strength of the copper/photopolymer composite is increased over 45 per cent at 20 phr copper loading. The hardness of the photopolymer has a negative correlation with the increasing copper loading and is decreased about 28.5 per cent at 100 phr copper loading. The degradation temperature of the copper/photopolymer composite is increased about 7.2 per cent at 70 phr copper loading. The thermal conductivity of the copper/photopolymer composite is increased over 65 per cent at 100 phr copper loading.
Originality/value
The photopolymer used in rapid prototyping system is generally fragile and has poor thermal properties. This study improves the thermal and mechanical properties of the photopolymer with the copper filling which has been never investigated in the field of rapid prototyping applications.
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Mohammed I. Abdulsalam and Francisco Presuel-Moreno
The purpose of this paper is to study the susceptibility of these three commonly used corrosion resistance fasteners in seawater. For a more practical scenario, a local Atlantic…
Abstract
Purpose
The purpose of this paper is to study the susceptibility of these three commonly used corrosion resistance fasteners in seawater. For a more practical scenario, a local Atlantic coastal seawater as received was used.
Design/methodology/approach
Carbon fiber reinforced polymer (CFRP) was fabricated with T700 carbon fiber (Toray Inc.) and VE8084 vinyl ester resin (Ashland) to make a unidirectional composite panel of thickness 1.8 mm. A conductive paint was applied to one of the sample edges that was perpendicular to the fiber direction, providing an electrical contact with carbon fibers to connect a copper wire. This external electric connection was used for potential measurements of both the open circuit potential (OCP) of the CFRP sample, and the mixed potential of the fastened set: consisting of the CFRP and the metallic fastener fastened to it. Three common fastener alloys were selected: 316SS, Monel and Titanium. For this purpose, a high impedance voltmeter was used in conjunction with a saturated calomel reference electrode. Measurements were taken daily. For longer time measurements, a four-channel high impedance analog data logger was used with 30 min sampling rate.
Findings
For both 316SS and Monel fastened sets, crevice corrosion occurred inside the occluded regions of the set, when immersed in coastal seawater. The attack was more severe for 316 stainless steel set. An isolated island attack of faceted surfaces morphology was seen for 316SS set. While, a circular ring of preferential grain boundary attack appeared for Monel set, indicating an IR (voltage) drop mechanism is more likely operating. Titanium-fastened sets showed high resistance to crevice corrosion when simmered in seawater. However, for long-time exposure, the sets became more susceptible to crevice corrosion attack supported by CFRP attachment (oxygen reduction reaction taking place at the carbon fibers).
Originality/value
Evidently, titanium, stainless steels and Monel are good candidates for galvanic corrosion resistance. However, their susceptibility to crevice corrosion when coupled with CFRP is a new challenging topic that needs further investigation. This is very important today because the vast application witnessed for CFRP material. This work involves developing an original methodology for this kind of investigation and was done at advanced laboratories of SeaTech at Florida Atlantic University by the Atlantic coastline.
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Hsiang‐Fu Yu, Yi‐Ming Chen, Shih‐Yong Wang and Li‐Ming Tseng
Traditionally, file transfer protocol (FTP) servers are major archive providers and users apply the Archie server to locate FTP archives. With the extreme popularity of the WWW…
Abstract
Traditionally, file transfer protocol (FTP) servers are major archive providers and users apply the Archie server to locate FTP archives. With the extreme popularity of the WWW, Web servers are now important archive providers and users download archives via HTTP. To reduce HTTP traffic, proxy cache servers are deployed on the Internet. However, we find the hit rate of archives in cache servers is quite low. This study proposes a combination of caching and better searching mechanisms to alleviate the problem. We enable a proxy server to automatically collect WWW and FTP archives from its cache, organize them in the form of an FTP directory, and then offer the directory list to the Archie. Accordingly, users can find archives on WWW and FTP servers through the Archie, and they can directly download archives from the proxy server, thus improving the reuse of cached archives. A system was implemented and operated in a real environment to evaluate the approach and results are discussed.
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Yi-Ming Wei, Bi-Ying Yu, Hui Li, Jia-Ning Kang, Jin-Wei Wang and Wei-Ming Chen
Climate engineering management (CEM) as an emerging and cross-disciplinary subject gradually draws the attention to researchers. This paper aims to focus on economic and social…
Abstract
Purpose
Climate engineering management (CEM) as an emerging and cross-disciplinary subject gradually draws the attention to researchers. This paper aims to focus on economic and social impacts on the technologies of climate engineering themselves. However, very few research concentrates on the management of climate engineering. Furthermore, scientific knowledge and a unified system of CEM are limited.
Design/methodology/approach
In this paper, the concept of CEM and its characteristics are proposed and elaborated. In addition, the framework of CEM is established based on management objectives, management processes and supporting theory and technology of management. Moreover, a multi-agent synergistic theory of CEM is put forward to guide efficient management of climate engineering, which is composed of time synergy, space synergy, and factor synergy. This theory is suitable for solving all problems encountered in the management of various climate engineering rather than a specific climate engineering. Specifically, the proposed CEM system aims to mitigate the impact of climate change via refining and summarizing the interrelationship of each component.
Findings
Overall, the six research frontiers and hotspots in the field of CEM are explored based on the current status of research.
Originality/value
In terms of the objectives listed above, this paper seeks to provide a reference for formulating the standards and norms in the management of various climate engineering, as well as contribute to policy implementation and efficient management.