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Final Assembly (final + assembly)
Selected AbstractsAnisotropic Particle Synthesis Inside Droplet Templates on Superhydrophobic SurfacesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 2 2010Vinayak Rastogi Abstract We demonstrate how droplet templates dispensed on superhydrophobic substrates can be used to fabricate both shape-anisotropic ("doughnut") and composition-anisotropic ("patchy magnetic") supraparticles. The macroscopic shape of the closely-packed particle assemblies is guided by the droplet meniscus. Aqueous droplets of monodisperse microsphere suspensions dispensed on the substrates initially acquire near-spherical shape due to a high contact angle. During the solvent evaporation, however, silica suspension droplets undergo shape transitions (concaving) guiding the structure of the final assemblies into doughnut supraparticles. Composition anisotropy is achieved by drying a droplet containing a mixed suspension of latex and magnetic nanoparticles, while exposing it to magnetic field gradients. Depending on the pattern of the magnetic fields, the magnetic nanoparticles segregate into single, bilateral, or trilateral, patched spherical supraparticles. The physical effects leading to the development of anisotropy are discussed. Unlike the conventional wet self-assembly (WSA) methods where the final structures need to be extracted from the liquid environment, this efficient one-step procedure produces ready to use "dry" supraparticles. [source] Enantioselective Synthesis of the Originally Proposed Usneoidone Structure: Evidence for a Structural RevisionEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2004Michèle Danet Abstract The enantioselective synthesis of the initially proposed structure of usneoidone has been completed according to a convergent strategy in which the key steps were an enantioselective Michael addition involving chiral imines to set up the C12 quaternary center, and the final assembly of the chiral pyran moiety with the aromatic subunit through a cyanohydrin anion alkylation step. The obtained product displays spectroscopic data that significantly differ from the reported values. A putative revised structure in which the pyran ring is opened is proposed for usneoidones. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Petrology and P,T path of the Fuping mafic granulites: implications for tectonic evolution of the central zone of the North China cratonJOURNAL OF METAMORPHIC GEOLOGY, Issue 4 2000G. C. Zhao The Fuping Complex and the adjoining Wutai and Hengshan Complexes are located in the central zone of the North China craton. The dominant rock types in the Fuping Complex are high-grade tonalitic,trondhjemitic,granodioritic (TTG) gneisses, with minor amounts of mafic granulites, syntectonic granitic rocks and supracrustal rocks. The petrological evidence from the mafic granulites indicates three stages of metamorphic evolution. The M1 stage is represented by garnet porphyroblasts and matrix plagioclase, quartz, orthopyroxene, clinopyroxene and hornblende. Orthopyroxene+plagioclase symplectites and clinopyroxene+plagioclase±orthopyroxene coronas formed in response to decompression during M2 following the peak metamorphism at M1. Hornblende+plagioclase symplectites formed as a result of further isobaric cooling and retrograde metamorphism during M3. The P,T estimates using TWQ thermobarometry are: 900,950 °C and 8.0,8.5 kbar for the peak assemblage (M1), based on the core compositions of garnet, matrix pyroxene and plagioclase; 700,800 °C and 6.0,7.0 kbar for the pyroxene+plagioclase symplectites or coronas (M2); and 550,650 °C and 5.3,6.3 kbar for the hornblende+plagioclase symplectites (M3), based on garnet rim and corresponding symplectic mineral compositions. These P,T estimates define a clockwise P,T path involving near-isothermal decompression for the Fuping Complex, similar to the P,T path estimated for the metapelitic gneisses. The inferred P,T path suggests that the Fuping Complex underwent initial crustal thickening, subsequent exhumation, and finally cooling and retrogression. This tectonothermal path is similar to P,T paths inferred for the Wutai and Hengshan Complexes and other tectonic units in the central zone of the North China craton, but different from anti-clockwise P,T paths estimated for the basement rocks in the eastern and western zones of the craton. Based on lithological, structural, metamorphic and geochronological data, the eastern and western zones of the craton are considered to represent two different Archean to Paleoproterozoic continental blocks that amalgamated along the central zone at the end of Paleoproterozoic. The P,T paths of the Fuping Complex and other tectonic units in the central zone record the collision between the eastern and western zones that led to the final assembly of the North China craton at c. 1800 Ma. [source] Virtual Shop Clusters: A New Layout Concept for a Ship Repair and Maintenance FacilityNAVAL ENGINEERS JOURNAL, Issue 2 2008BRIAN MAYER Organic ship maintenance facilities and depots of the Navy are mostly organized as trade-specific shops rather than by product (or process) families. For example, welders are in the weld shop, machinists are in the machine shop, pipe-fitters are in the pipe shop, etc. There is a belief that this guild-type organizational structure is what enables a repair facility to do almost anything, albeit at the cost of moving product all over the "factory." This skill-based organizational structure is identical to the functional (or department) layout that is preferred by most jobshops in the commercial manufacturing sectors. But, any company that has successfully implemented Lean Thinking has almost always replaced a Functional (or Process Village) Layout by a Cellular Layout. At the Navy's Southeast Regional Maintenance Center (SERMC), a typical repair job must visit multiple shops that pass work back and forth between them. For example, a pipe job may be sent by the pipe shop to the machine shop for re-threading, then routed to the weld shop where it is welded to a frame, after which the welded sub-assembly returns to the pipe shop for inspection and final assembly. Thereby, significant delays and operational wastes occur because people have to walk between the shops, discuss matters at daily production meetings, and e-mail/phone each other to make sure that their schedules match. If activities are not completed as per schedule, the jobs get further delayed because they queue at the shops, waiting to be served. This lack of detailed (and accurate) planning and scheduling, combined with poor schedule visibility and shop floor control, is the curse of the Functional Layout that currently exists at SERMC. This paper will describe a pilot project to assess the feasibility of cellular manufacturing at SERMC. The fundamental hypothesis that was tested is that even in a repair and maintenance facility there could exist several families of repair jobs where jobs grouped into a family require similar combinations of processes, equipment, materials, etc. that can be provided by a small group of shops. In fact, several potential families of repair jobs, and the appropriate cluster of shops for each family of repair jobs, were identified using the Production Flow Analysis and Simplification Toolkit (PFAST) software. Based on these results, it was decided to implement a shop cluster (or focused factory, or repair cell) to complete any repair jobs done by the dive shop. It was recommended that the dive shop be merged with a few other shops, and be provided the necessary tools, cross-trained personnel, equipment, and other support systems to become an autonomous multi-function shop. Simulation using the SimCAD software from CreateAsoft Inc. (http://www.createasof.com) was used to verify the results expected from making the proposed changes. The primary analysis was intended to evaluate the benefits of implementing a focused factory in the dive shop. The secondary analysis was intended to evaluate the advantages of implementing a virtual shop cluster (or focused factory, or repair cell) in any ship repair facility like SERMC. The simulation results showed that implementing either physical cells or virtual cells based on the different families of repair jobs identified by PFAST could improve job turnaround times at any Navy ship repair facility like SERMC. Both the types of delays as well as the time values of these delays differed significantly across the existing and alternative shop configurations that were proposed. [source] Jurassic synorogenic basin filling in western Korea: sedimentary response to inception of the western Circum-Pacific orogenyBASIN RESEARCH, Issue 4 2009Kosuke Egawa ABSTRACT This is the first sedimentologic and stratigraphic attempt to demonstrate Jurassic subduction-induced basin-filling processes in the early stage of the western Circum-Pacific orogeny. The Chungnam Basin in western Korea was filled with a Lower to Middle Jurassic nonmarine succession, the Nampo Group, whose deposition postdated the Triassic final assembly of Chinese continental blocks. The Nampo Group consists of two repeated, fining- to coarsening-upward alluvio-lacustrine sequences, separated by an interval of thick breccia,gravel progradation deposits and its related strong proximal unconformities. No temporal variation in the degree of chemical weathering, along with the predominance of coals and a tropic to subtropic paleoflora, reveals little or no climate fluctuations during deposition of the Nampo Group. The observed relationships provide a record of sedimentation most likely controlled by temporal variations of tectonically driven sediment flux. Such syntectonic sedimentation of the Chungnam Basin occurred at a convergent margin of continental-arc setting during the Daebo orogeny, synchronous with the early subduction of the western paleo-Pacific ocean that resulted in formation of an accretionary complex along the East Asian continental margin during Jurassic time. Hence, synorogenic deposition in the Chungnam Basin is interpreted as sedimentary response to subduction,accretion of the western paleo-Pacific plate. [source] | ||||||||||