MIM of Titanium

Hartwig Thomas 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

The metal injection molding process was applied to produce Ti-6Al-7Nb alloys using 3 types of mixed powders, first is a mixture of Ti and Al53.3Nb pre-alloyed powders, second is a mixture of Ti, TiAl and Nb powders, and third is a mixed elemental powders of Ti, Al and Nb. The effects of the 3 types of mixed powders and sintering conditions on the microstructure, relative density and mechanical properties of injection molded compacts were mainly investigated. The sintered compacts using first and second powders showed higher density and mechanical properties as compared to the compacts using the third powder which existed many and a little large pores in the microstructure because of the melting of Al during sintering steps. Also the oxygen content of the compacts using second powder was higher than that of the compacts using other powders. Eventually, the mechanical properties of the compacts using a mixture of Ti+Al53.3Nb or Ti+TiAl+Nb powders were above 800MPa in tensile strength and above 10% in elongation, which were similar to the properties of wrought materials.

Investigating Science-Policy Interfaces in Japanese Politics through Climate Change Discourse Coalitions of an Environmental Policy Actor Network

Hartwig, Manuela G. World Association for Triple Helix and Future Stra 2019 Journal of Contemporary Eastern Asia Vol.18 No.2

How is science advice integrated in environmental policymaking? This is an increasingly pertinent question that is being raised since the nuclear catastrophe of Fukushima, Japan, in 2011. Global re-evaluation of energy policies and climate mitigation measures include discussions on how to better integrate science advice in policymaking, and at the same time keeping science independent from political influence. This paper addressed the policy discourse of setting up a national CO2 reduction target in Japanese policymaking between 2009 and 2012. The target proposed by the former DPJ government was turned down, and Japan lacked a clear strategy for long-term climate mitigation. The analysis provides explanations from a quantitative actor-network perspective. Centrality measures from social network analysis for policy actors in an environmental policy network of Japan were calculated to identify those actors that control the discourse. Data used for analysis comes from the Global Environmental Policy Actor Network 2 (GEPON 2) survey conducted in Japan (2012-13). Science advice in Japan was kept independent from political influence and was mostly excluded from policymaking. One of the two largest discourse coalitions in the environmental policy network promoted a higher CO2 reduction target for international negotiations but favored lowering the target after a new international agreement would have been set. This may explain why Japan struggled to commit to long-term mitigation strategies. Applying social network analysis to quantitatively calculate discourse coalitions was a feasible methodology for investigating "discursive power." But limited in discussing the "practice" (e.g. meetings, telephone, or email conversations) among the actors in discourse coalitions.

단보 : 지속가능발전을 위한 지리교육 선언

Hartwig Haubrich,Sibylle Reinfried,Yvonne Schleicher,이종원(역) 한국지리환경교육학회 2008 한국지리환경교육학회지 Vol.16 No.3

Analysis of the Policy Network for the “Feed-in Tariff Law” in Japan: Evidence from the GEPON Survey

Okura, Sae,Tkach-Kawasaki, Leslie,Kobashi, Yohei,Hartwig, Manuela,Tsujinaka, Yutaka World Association for Triple Helix and Future Stra 2016 Journal of Contemporary Eastern Asia Vol.15 No.1

Energy policy is known to have higher path dependency among policy fields (Kuper and van Soest, 2003; OECD, 2012; Kikkawa, 2013) and is a critical component of the infrastructure development undertaken in the early stages of nation building. Actor roles, such as those played by interest groups, are firmly formed, making it unlikely that institutional change can be implemented. In resource-challenged Japan, energy policy is an especially critical policy area for the Japanese government. In comparing energy policy making in Japan and Germany, Japan’s policy community is relatively firm (Hartwig et al., 2015), and it is improbable that institutional change can occur. The Japanese government’s approach to energy policy has shifted incrementally in the past half century, with the most recent being the 2012 implementation of the “Feed-In Tariff Law” (Act on Special Measures Concerning Procurement of Renewable Electric Energy by Operators of Electric Utilities), which encourages new investment in renewable electricity generation and promotes the use of renewable energy. Yet, who were the actors involved and the factors that influenced the establishment of this new law? This study attempts to assess the factors associated with implementing the law as well as the roles of the relevant major actors. In answering this question, we focus on identifying the policy networks among government, political parties, and interest groups, which suggests that success in persuading key economic groups could be a factor in promoting the law. Our data is based on the “Global Environmental Policy Network Survey 2012-2013 (GEPON2)” which was conducted immediately after the March 11, 2011 Great East Japan Earthquake with respondents including political parties, the government, interest groups, and civil society organizations. Our results suggest that the Feed in Tariff (FIT) Law’s network structure is similar to the information network and support network, and that the actors at the center of the network support the FIT Law. The strength of our research lays in our focus on political networks and their contributing mechanism to the law’s implementation through analysis of the political process. From an academic perspective, identifying the key actors and factors may be significant in explaining institutional change in policy areas with high path dependency. Close examination of this issue also has implications for a society that can promote renewable and sustainable energy resources.

Improving the Precision of Specifications by Evaluating the Influence of Test Parameters on Tribological Results

Mathias Woydt,Hartwig Weber 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.37 No.-

A series of cooperative interlaboratory tests (round robins) was conducted in 1997, 1998, 1999, 2000, 2001, 2002 and 2003 by the DIN 51834 Working Group on Tribological Tests in Translatory Oscillation Apparatus. The statistical analysis of these test results shows the influence of cleaning solvent, machine model and evaluation criteria on the tribological properties of the lubricants tested. Coefficients of friction and wear results are ranked according to the effects of ten different cleaning solvents, where isopropanol gave the lowest values and isoparaffin solvents the highest. The effect of machine model on coefficients of friction varied from about 0.2 % to 0.9 % of the mean. Wear results were not affected. The tests also showed that the seizure criteria and methods of measuring wear required for in the test procedure do not provide a suitable measure of the tribological properties of some lubricants. The precision was improved by introducing a grease apply caliper as well as an increased stroke to 1,5 mm and running-in. The temperature does not affect the precision of the oil test procedure.

The Influence of Turbulence Promoters on Subcooled Flow Boiling

Sandra Kuhne,Hartwig Boye,Gerd H. D. Muhlenbruch,Jurgen Schmidt 대한기계학회 1998 Heat transter conference Vol.2 No.1

Shape memory polyurethanes cross-linked by surface modified silica particles

Jang, Moon Kyoung,Hartwig, Andreas,Kim, Byung Kyu Royal Society of Chemistry 2009 Journal of materials chemistry Vol.19 No.8

<P>Thermoresponsive polyurethane (PU)–silica nanocomposites were synthesized by incorporating silica particles as multifunctional cross-linkers into the PU <I>via</I> sol–gel reactions. At 2 wt% silica, the composites showed over 99% shape fixity and shape recovery up to the 4th thermomechanical cycle along with outstanding mechanical properties in their rubbery as well as glass state. The incorporated nano-sized silica particles gave dual effects of multifunctional chemical cross-links and reinforcing fillers. The properties were favorably compared with those of uncross-linked PU and conventionally cross-linked PU.</P> <P>Graphic Abstract</P><P>Silica particles (2%) incorporated into polyurethanes as multifunctional cross-links provided over 99% shape fixity and recovery up to the 4th thermomechanical cycle along with outstanding mechanical properties. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b816691a'> </P>

Towards Methionine Overproduction in Corynebacterium glutamicum -Methanethiol and Dimethyldisulfide as Reduced Sulfur Sources

( Christoph J. Bolten ),( Hartwig Schroder ),( Jeroen Dickschat ),( Christoph Wittmann ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.8

In the present work, methanethiol and dimethyldisulfide were investigated as sulfur sources for methionine synthesis in Corynebacterium glutamicum. In silico pathway analysis predicted a high methionine yield for these reduced compounds, provided that they could be utilized. Wild-type cells were able to grow on both methanethiol and dimethyldisulfide as sole sulfur sources. Isotope labeling studies with mutant strains, exhibiting targeted modification of methionine biosynthesis, gave detailed insight into the underlying pathways involved in the assimilation of methanethiol and dimethyldisulfide. Both sulfur compounds are incorporated as an entire molecule, adding the terminal S-CH3 group to O-acetylhomoserine. In this reaction, methionine is directly formed. MetY (O-acetylhomoserine sulfhydrylase) was identified as the enzyme catalyzing the reaction. The deletion of metY resulted in methionine auxotrophic strains grown on methanethiol or dimethyldisulfide as sole sulfur sources. Plasmid-based overexpression of metY in the △metY background restored the capacity to grow on methanethiol or dimethyldisulfide as sole sulfur sources. In vitro studies with the C. glutamicum wild type revealed a relatively low activity of MetY for methanethiol (63 mU/mg) and dimethyldisulfide (61 mU/mg). Overexpression of metY increased the in vitro activity to 1,780 mU/mg and was beneficial for methionine production, since the intracellular methionine pool was increased 2-fold in the engineered strain. This positive effect was limited by a depletion of the metY substrate O-acetylhomoserine, suggesting a need for further metabolic engineering targets towards competitive production strains.