TAILIEUCHUNG - POWDER METALLURGY_2

From high-performance, economical and environmental points of view, Powder metallurgy process shows remarkable advantages in production of parts and components due to their special compositions by elemental mixing and 3-dimensional near net shape forming methods. Powder metallurgy process can be applied to not only metal materials but also ceramics and organic materials, which both are employed as structural and electrical products. | Part 3 The Changing Climate 9 Paleotempestology Reconstructing Atlantic Tropical Cyclone Tracks in the Pre-HURDAT Era Jill S. M. Coleman and Steven A. LaVoie Ball State University USA 1. Introduction The study of past tropical cyclone activity by means of geological proxies and or historical documentary records is known as paleotempestology. This scientific discipline has become prominent over the course of the last decade partially in response to the recent increase in tropical cyclone count and intensity in the North Atlantic basin witnessed since 1995. The field has also developed due to the socioeconomic impacts of tropical cyclones particularly along vulnerable coastal regions. During the twenty-five years prior to the start of the most recent increase in hurricane activity major Category 3 4 or 5 hurricanes were less frequent than in previous decades. Yet property losses from the hurricanes that did make landfall in the United States increased during this period due to development in damage prone areas NOAA Paleoclimatology Program 2000 . Many researchers hence stress the importance of identifying historical tropical cyclones to understand long term trends in tropical cyclone climatology and to determine the influence of anthropogenic global warming on tropical cyclone activity and intensity. The North Atlantic Hurricane Database HURDAT has been one of the authoritative sources for examining North Atlantic tropical cyclone activity trends since 1850. However some of the deadliest known hurricanes and potentially most active seasons in the North Atlantic basin occurred prior to the beginning of the HURDAT record Table 1 including the Great Hurricane of 1780 that killed an estimated 22 000 people and was one of eight known tropical cyclones during that season. This chapter will provide a brief overview of some paleotempestology techniques and illustrate a methodology for identifying and reconstructing historical North Atlantic tropical cyclone tracks in the .

• Cơ khí - Chế tạo máy
• environmental points
• Powder metallurgy
• elemental mixing
• forming methods
• organic materials
• actual components
• Regional Synthesis
• Sub Regional Overviews
• opportunities for development
• mproving Understanding
• environmental agreements