1,329 research outputs found
Analysis of Hypersonic Vehicle Wakes
As advancements are made with ballistic missiles, particularly in the area of hypersonic bodies, there is a growing need to advance the methods of detecting these new ballistic weapons. As a result, the National Air and Space Intelligence Center has asked the Air Force Institute of Technology to examine the wake region behind hypersonic bodies. A thorough understanding of the aerothermal phenomena and the chemical reactions occurring in the wake region will enable an advancement of tracking hypersonic bodies. This research examined the wake region behind a hypersonic body using computational fluid dynamics. This study used Pointwise® to develop a three-dimensional grid of the flowfield around a conic hypersonic body and extending into the wake region. The Langley Aerothermodynamic Upwind Relaxation Algorithm was used to solve the flowfield, including the wake, and all surface properties. The results from the simulation were used to characterize the wake region behind the hypersonic body and compare that to the flowfield surrounding the body.Although no flight test data was available and no published results could be found in this area of interest, the results had good agreement with expected results. Along with that, several interesting phenomena were discovered dealing with the aerothermal environment and chemical species present in the wake that could lead to advancements in the efforts of tracking hypersonic bodies
Environmental failure mode and effects analysis (FMEA) – a new approach to methodology
The purpose of this paper is to present a concept of FMEA analysis for environmental aspects, together with a discussion of the importance, implementation and application of the proposed concept. The analyses and the developed E-FMEA methodology have resulted in a proposal of management tools for manufacturing processes
Crystallographic orientation inhomogeneity and crystal splitting in biogenic calcite
The calcitic prismatic units forming the outer shell of the bivalve Pinctada margaritifera have been analysed using scanning electron microscopy–electron back-scatter diffraction, transmission electron microscopy and atomic force microscopy. In the initial stages of growth, the individual prismatic units are single crystals. Their crystalline orientation is not consistent but rather changes gradually during growth. The gradients in crystallographic orientation occur mainly in a direction parallel to the long axis of the prism, i.e. perpendicular to the shell surface and do not show preferential tilting along any of the calcite lattice axes. At a certain growth stage, gradients begin to spread and diverge, implying that the prismatic units split into several crystalline domains. In this way, a branched crystal, in which the ends of the branches are independent crystalline domains, is formed. At the nanometre scale, the material is composed of slightly misoriented domains, which are separated by planes approximately perpendicular to the c-axis. Orientational gradients and splitting processes are described in biocrystals for the first time and are undoubtedly related to the high content of intracrystalline organic molecules, although the way in which these act to induce the observed crystalline patterns is a matter of future research
Fabrication and selected properties of multilayer Fe/Cu systems
The paper presents investigation results of the structure and selected physical properties of multilayer systems obtained by the electrolysis method. The obtained samples compose of 20 alternate layers of Fe/Cu with the following single layer thicknesses: 50 nm and 100 nm. The multilayer Fe/Cu systems for electromagnetic field shielding are characterized by relatively good quality. On the basis of topographical tests, no major defects have been found. As a result of magnetic studies, it has been found that the samples are magnetically soft materials
Potensi Mitigasi Emisi Gas Rumah Kaca dari Kegiatan Eksplorasi dan Produksi Minyak dan Gas Bumi di PT. Xyz
The activity of exploration and production in oil and gas industry is significant greenhouse gas (GHG) emission source. PT. XYZ is one of upstream oil and gas industry in Indonesia and it have large crude oil and gas potential with it reserves that not manage yet. Therefore, GHG emission potential from the activity of exploration and production in PT. XYZ is very large. This study is done for estimate GHG emission reduction potential in PT. XYZ from various activities. Emission inventory is the first step to estimate GHG released to atmosphere. Method of estimation use the method developed by American Petroleum Institute (API). This study considers three types of mitigation measures options, including technical options (scenario 1), behavior option (scenario 2), and policy option (scenario 3). Based on emission inventory, flare and oil storage tank are primary source of GHG emissions in PT. XYZ. Scenario 1 prefers control of GHG emissions in flare and storage tank as primary emission source. While others scenario prefers to control GHG emission from transportation sector. Scenario 1 has potential to reduce emissions by 48.3 %. While scenario 2, and 3 in sequences have potential to reduce emissions by 0.15%, and 0.52%. Emissions flare and oil storage tank can be reduced through the installation of flaring gas recovery unit and vapor recovery unit. Both are effective and efficient in reducing GHG emissions in PT. XYZ. In addition, all mitigation measures of transportation sector provide benefits even though the amount of GHG that can be reduced is not significant
Leading Boldly: Foundations Can Move Past Traditional Approaches to Create Social Change Through Imaginative -- Even Controversial -- Leadership
Rarely do foundations publicly communicate their dissatisfaction with their grantees, withhold funds, or use tactics that carry the risks of creating ill will. Yet extraordinary results can be achieved if foundations were more imaginative, visible, and controversial. Three foundations shocked the city of Pittsburgh in 2002 by abruptly suspending their funding to local public schools. The foundations announced their decision in a news conference that attracted both local and national coverage -- a sharp departure from their usual approach of working quietly behind the scenes. Foundation executives explained that they had completely lost confidence in the ability of the local school board to run the district. Their action yielded a community-wide process that led to real change. Here's how foundations can exercise Adaptive Leadership without misusing authority
Tinjauan Hukum Internasional Mengenai Eksistensi Konsul Kehormatan (Honorary Consul) dalam Hubungan Konsuler (Studi Kasus: Konsul Kehormatan Jerman di Medan)
Regarding of the implementation of peaceful relations between countries, which generally marked by the opening of diplomatic relations and in addition followed by the opening of consular relations. Diplomatic relations are political while consular relations is non-political and tends to take care of administrative and commercial issues. To carry out consular functions in a foreign country who establishes consular relations with it, a country appointed the consular officer. Vienna Convention 1963 classifies consular officials into namely Career Consular Officers and Honorary Consular Officers. Indonesia and Germany have officially established diplomatic relations since 1952 and at present Germany representatives in Indonesia consists of an embassy and three Honorary Consuls, one of which located in Medan. The scope of consular relations by Germany Honorary Consul in Medan consists of honorary consulate opening, the appointment of honorary consuls and operational matters of consular relations by the honorary consul. Tasks and functions of the of Germany Honorary Consul in the field are based on the provisions contained in Konsulargesetz which is an affirmation of the Vienna Convention 1963. While the immunity and privileges acquired by Germany Honorary Consul in Medan in carrying out its tasks and functions are very limited. It is recommended for reasons of economy and efficiency, the appointment of honorary consuls may be the right choice for countries that want to open a consular representative at the present time. In carrying out its tasks and functions, Germany Honorary Consul in Medan can enhance its role as a liaison of the business activities between Germany and Indonesia. Therefore, in terms of granting immunities and privileges of the Honorary Consul, Indonesia and Germany should make a special agreement on the matter in order to ensure a honorary consul can carry out his functions without a hitc
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