A new art code for tomographic interferometry

A new algebraic reconstruction technique (ART) code based on the iterative refinement method of least squares solution for tomographic reconstruction is presented. Accuracy and the convergence of the technique is evaluated through the application of numerically generated interferometric data. It was found that, in general, the accuracy of the results was superior to other reported techniques. The iterative method unconditionally converged to a solution for which the residual was minimum. The effects of increased data were studied. The inversion error was found to be a function of the input data error only. The convergence rate, on the other hand, was affected by all three parameters. Finally, the technique was applied to experimental data, and the results are reported

Development of fiber-based laser anemometer for SSME application

A recent study by Rocketdyne for NASA identified laser anemometry, using a compact optical head, as a feasible diagnostic instrument for the Space Shuttle Main Engine (SSME) Model Verification experiments. Physical Research, Inc. (PRI) is presently under contract from NASA Lewis to develop and deliver such a laser anemometer system. For this application, it is desired to place the laser at a remote distance from the engine, and use single mode polarization preserving fiber optics for the transmission of the laser light to and from the measurement head. Other requirements are given. Analytical and experimental tools are being used to develop the technologies required for the laser anemometer. These include finite element analysis of the optical head and vibration tests for various optical and mechanical components. Design of the optical head and the fiber optic connectors are driven by the temperature and vibration requirements for the measurement environment. Results of the finite element analysis and the vibration tests of the components are included. Conceptual design of the fiber optic launcher and the optical probe has also been complete. Detailed design of the probe as well as the fabrication and assembly of the components is in progress

De lockande bronsen från Luristan: En diskussion om samlandet och plundrandet av arkeologiskt arv

En önskan att äga antika föremål påverkade det arkeologiska arvet och den arkeologiska vetenskapen under första halvan av 1900-talet, en tid då arkeologiska föremål blev populära samlingsobjekt på en bred skala, och då plundrandet av arkeologiskt arv ökade. I denna artikel undersöks iransk arkeologi och plundrandet av föremål som på engeslska kallas "Luristan Bronzes", alltså ”Bronsen från Luristan”. Rollen av samtida etik, museer och forskare diskuteras, tillika med pågående internetförsäljning av bronsföremålen. Med tanke på det arkeologiska arvets framtid är det ytterst viktigt att diskutera och sprida kunskap om kulturarvsfrågor. En bättre medvetenhet om kulturarvets betydelse borde uppmuntras på en lokal och global skala, och man borde dessutom uppmuntra till en mindre tolerant inställning gentemot samlandet av olagligt tillägnade arkeologiska föremål. Forskare och museer har en viktig roll i denna proces

Remote detection of boundary-layer transition by an optical system

This instrument development program was funded because of the urgent need to measure boundary-layer transition in wind tunnels. In the course of this development program, a prototype was designed, built, and tested. Recent transonic experiments in the Boeing Model Transonic Wind Tunnel show that the interferometer results correlate very well with sublimating chemical tests

Challenges of outsourcing logistics to third-party providers

The focus of this study is on the challenges that shippers faced using Third-Party Logistics (3PL) providers. The study is based on a mail survey of 126 shippers and personal interviews with eight shipper executives and four 3PL provider executives. The study first identifies the major challenges including, finding a 3PL with the capabilities meeting the shipper\u27s specific logistics requirements, the incompatibility of information systems between shipper and 3PL, the failure of 3PL to meet a shipper\u27s future growth needs, and issues related to security. Second, it offers some recommendations for shippers to consider in overcoming any challenges encountered. Copyright © 2010 Inderscience Enterprises Ltd

The effect of transnational threats on the security of Persian Gulf maritime petroleum transportation

Today\u27s interconnected economy is dependent on petroleum products as a principal component of the energy mix and a critical element in global infrastructures. With the escalating demand for oil and natural gas, the world relies heavily on maritime transportation to move 62 % of world trade on fixed routes. The Persian Gulf countries are crucial because about 88 % of oil exports pass through the Strait of Hormuz. The Strait is strategically located between Iran and Oman, where 20 million barrels of crude oil per day is carried by supertankers. These shipments account for 40 % of seaborne oil traded worldwide. According to the Energy Information Administration, due to increasing demand this region will require 2. 5 times more tankers than are in existence today to meet demand by 2025. Nevertheless, the persistent, expanding, and increasingly sophisticated physical attacks against maritime transportation present an alarming pattern. The focus of this article is three fold. First, to explain major transnational threats within the context of piracy and terrorism. Second, to present the costs and the economic impacts of piracy and terrorism on international trade. Third, to point out the main contributing factors involved in the increase in the number of attacks on maritime petroleum transportation vessels. Given the strategic importance of the Persian Gulf countries, due to their petroleum contributions to the world, this paper focuses on the maritime flows of petroleum from this region through navigation courses to Asia, the United States, and Europe. © 2012 Springer Science+Business Media, LLC

Investigation of Turbulent Boundary-Layer Separation Using Laser Velocimetry

Boundary-layer measurements realized by laser velocimetry are presented for a Much 2.9, two-dimensional, shock-wave/turbulent boundary-layer interaction containing an extensive region of separated flow. Mean velocity and turbulent intensity profiles were obtained from upstream of the interaction zone to downstream of the mean reattachment point. The superiority of the laser velocimeter technique over pressure sensors in turbulent separated flows is demonstrated by a comparison of the laser velocimeter data with results obtained from local pilot and static pressure measurements for the same flow conditions. The locations of the mean separation and reattachment points as deduced from the mean velocity measurements are compared to oil-now visualization results. Representative velocity probability density functions obtained in the separated now region are also presented. Critical to the success of this investigation were: the use of Bragg cell frequency shifting and artificial seeding of the now with submicron light-scattering particles

Optical surface contouring for non-destructive inspection of turbomachinery

Detection of stress cracks and other surface defects during maintenance and in-service inspection of propulsion system components, including turbine blades and combustion compartments, is presently performed visually. There is a need for a non-contact, miniaturized, and fully fieldable instrument that may be used as an automated inspection tool for inspection of aircraft engines. During this SBIR Phase 1 program, the feasibility of a ruggedized optical probe for automatic and nondestructive inspection of complex shaped objects will be established. Through a careful analysis of the measurement requirements, geometrical and optical constraints, and consideration of issues such as manufacturability, compactness, simplicity, and cost, one or more conceptual optical designs will be developed. The proposed concept will be further developed and a prototype will be fabricated during Phase 2

Phase behavior of UCST blends: Effects of pristine nanoclay as an effective or ineffective compatibilizer

The effects of unmodified nanoclay (natural montmorillonite) on the miscibility, phase behavior and phase separation kinetics of polyethylene (PE)/ethylene vinyl acetate copolymer (EVA) blends have been investigated. Depending on the blend composition, it was observed that the intercalated pristine nanoclay influences the biphasic morphology either as an effective compatibilizer or just as an ineffectual modifier. In spite of the presence of micrometer-sized agglomerated tactoids, natural nanoclay can play a thermodynamic role in reducing the interfacial tension of polymer components. The addition of clay nanoparticles was found to change the phase diagram slightly and diminishes the composition dependency of the binodal temperatures. Moreover, it was observed that a small amount of unmodified layered silicate slows down the phase separation process considerably and enhances the solubility of each polymer in the domains of its counterpart. The findings of this study verify that even poorly dispersed nanoclay with high surface tension can act as a conventional compatibilizer and change the immiscible PE/EVA blends to the partially miscible ones

Outsourcing in the Persian Gulf petroleum supply chain

© 2016, © Emerald Group Publishing Limited. Purpose – The purpose of this study is to identify the challenges, the benefits, the risks and the motives of petroleum companies in the Persian Gulf toward outsourcing strategy. While the petroleum companies are faced with massive costs of operation that stem from the aging infrastructure, human capital deficit, inefficient fragmented business processes and lack of access to new technologies, outsourcing strategy toward cost savings and the overt and covert resistance of management and employees are significant barriers for creation of continuous process. Design/methodology/approach – Based on the review of existing literature, the industry\u27s archives and in-depth personal interviews with senior executives of the national oil and gas companies in five Gulf countries and seven global outsourcing companies and 87 survey responses, this study develops a methodological framework which substantiates or refutes the hypotheses based on the objectives: industry challenges are the driving forces behind outsourcing strategy; the potential risks of cost savings of outsourcing outweigh the consequential loss in control over the product or service, companies\u27 safety and security of the region. Findings – The findings indicate that the oil and gas exporters have mixed but broad positive view of outsourcing strategy. While outsourcing could provide savings across the entire supply chain, it also generates a distracting resistance due to the fear of unknown in a complex range of culture, infrastructures and sequential processes that requires resiliency for continuity of operations. Originality/value – This study is the first of its kind in the Persian Gulf oil and gas industry investigating the implementation of outsourcing strategy. The result of this investigation reveals the compromise between the potential benefits in cost reduction and the security of petroleum supply. This study contributes to all who are in the industry or who are involved with it to share a clear assessment of the future