2,324 research outputs found

    Mapping customer needs to engineering characteristics: an aerospace perspective for conceptual design

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    Designing complex engineering systems, such as an aircraft or an aero-engine, is immensely challenging. Formal Systems Engineering (SE) practices are widely used in the aerospace industry throughout the overall design process to minimise the overall design effort, corrective re-work, and ultimately overall development and manufacturing costs. Incorporating the needs and requirements from customers and other stakeholders into the conceptual and early design process is vital for the success and viability of any development programme. This paper presents a formal methodology, the Value-Driven Design (VDD) methodology that has been developed for collaborative and iterative use in the Extended Enterprise (EE) within the aerospace industry, and that has been applied using the Concept Design Analysis (CODA) method to map captured Customer Needs (CNs) into Engineering Characteristics (ECs) and to model an overall ‘design merit’ metric to be used in design assessments, sensitivity analyses, and engineering design optimisation studies. Two different case studies with increasing complexity are presented to elucidate the application areas of the CODA method in the context of the VDD methodology for the EE within the aerospace secto

    AC Loss and Contact Resistance In Copper-Stabilized Nb3Al Rutherford Cables with and without a Stainless Steel Core

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    Calorimetric measurements of AC loss and hence interstrand contact resistance (ICR), were measured on three samples of Rutherford cable wound with Cu-stabilized jelly-roll type unplated Nb3Al strand. One of the cable types was furnished with a thin core of AISI 316L stainless steel and the other two were both uncored but insulated in different ways. The cables were subjected to a room-temperature-applied uniaxial pressure of 12 MPa that was maintained during the reaction heat treatment (RHT), then vacuum impregnated with CTD 101 epoxy, and repressurized to 100 MPa during AC-loss measurement. The measurements were performed at 4.2 K in a sinusoidal field of amplitude 400 mT at frequencies of 1 to 90 mHz (no DC-bias field) that was applied both perpendicular and parallel to the face of the cable (the face-on, FO, and edge-on, EO, directions, respectively). For the cored cable the FO-measured effective ICR (FO-ICR), was 5.27 . Those for the uncored cables were less than 0.08 . As shown previously for NbTi- and Nb3Sn-based Rutherford cables, the FO-ICR can be significantly increased by the insertion of a core, although in this case it is still below the range recommended for accelerator-magnet use. Post-measurement dissection of one of the cables showed that the impregnating resin had permeated between the strands and coated the core with a thin, insulating layer excepting for some sintered points of contact. In the uncored cables the strands were coated with resin except for the points of interstrand contact. It is suggested that in the latter case this tendency for partial coating leads to a processing-sensitive FO-ICR.Comment: Four pages, with two figure

    Genetic diversity of eukaryotic ultraphytoplankton in the Gulf of Naples during an annual cycle

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    Eukaryotic ultraphytoplankton (<5 μm) are an important component of phytoplankton populations, Dot blot hybridisation analysis using class level 16S rRNA gene probes as well as clone libraries were used to investigate the diversity of these ultraphytoplankton during a 15 mo period (2003 to 2004) in the Gulf of Naples. Hybridisation data showed the presence of 3 main classes, Cryptophyceae, Chrysophyceae and Prymnesiophyceae, along with lower signals from the Pelagophyceae. Clone libraries also contained these 4 classes as well as sequences from the Dictyochophyceae, Bacillariophyceae and Prasinophyceae. However, the Prymnesiophyceae gave the dominant hybridisation signal and constituted the majority of each clone library. Their diversity, with a total of 190 sequences belonging to 114 operational taxonomic units (OTUs), probably allows them to dominate the ultraphytoplankton throughout the whole year under differing environmental conditions. Over 100 of these OTUs were unique to different libraries, suggesting a succession of different taxa during the year. The Cryptophyceae were present most of the year with 1 OTU, corresponding to a Plagioselmis prolonga strain from the Gulf of Naples, being the dominant taxon (28 % of sequences). A striking result was the high hybridisation signal from the Chrysophyceae, which showed a preference for the summer months. The Pelagophyceae were present between December and March. Most (80 %) of the sequences found in the clone libraries were not identical to available 16S rRNA gene sequences, indicating a high amount of hidden diversity for these algal classes. However, sequences from Prasinophyceae Clade II (Mamiellales) were not detected in the clone libraries

    A New Generation Nb3Sn Wire, and the Prospects for Its Use in Particle Accelerators

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    Development of design allowable data for Celion 6000/LARC-160, graphite/polyimide composite laminates

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    A design allowables test program was conducted on Celion 6000/LARC-160 graphite polyimide composite to establish material performance over a 116 K (-250 F) to 589 K (600 F) temperature range. Tension, compression, in-plane shear and short beam shear properties were determined for uniaxial, quasi-isotropic and + or - 45 deg laminates. Effects of thermal aging and moisture saturation on mechanical properties were also evaluated. Celion 6000/LARC-160 graphite/polyimide can be considered an acceptable material system for structural applications to 589 K (600 F)

    Huisgen-based conjugation of water-soluble porphyrins to deprotected sugars: Towards mild strategies for the labelling of glycans

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    Fully deprotected alkynyl-functionalised mono- and oligosaccharides undergo CuAAC-based conjugation with water-soluble porphyrin azides in aqueous environments. The mild reaction conditions are fully compatible with the presence of labile glycosidic bonds. This approach provides an ideal strategy to conjugate tetrapyrroles to complex carbohydrates

    Gobernanza del “espacio blanco”: desarrollo, identidad y procesos dinámicos para aumentar la sustentabilidad y la responsabilidad social

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    Sustentabilidade e responsabilidade social envolvem, de forma crescente, temáticas como identidade e qualidade de vida para entrar prontamente e de forma mais profunda nos processos de tomadade decisão, especialmente nos decisões intersetoriais. Para essa nova interação são necessários redesenhos e reformas de “governança”. Este artigo explora um case do sul da Bahia, no Brasil, onde um novo tipo de mecanismo de governança cruzada faz prever um direcionamento mais efetivo para os prementes desafios sociais, econômicos e ambientais do século XXI.Sustainability and social responsibility increasingly require ecological and social concerns like identity and quality of life to enter earlier and more deeply into the decision making process, especially intersector decisions. To accomplish this, new interaction designs and “governance” reforms are needed. This article explores a case in Southern Bahia, Brazil, where a new type of cross-sector governance mechanism holds promise for more effectively addressing pressing social, economic, and environmental challenges of the 21st century.Sustentabilidad y responsabilidad social envuelven, de forma creciente, temáticas como identidad y cualidad de vida para entrar rápidamente y de forma más profunda en los procesos de tomada de decisión, especialmente en las decisiones intersectoriales. Para esa nueva interacción son necesarios rediseños y reformas de “gobernanza”. Este artículo explorará un case del sud de Bahía, en el Brasil, donde un nuevo tipo de mecanismo de gobernanza cruzada hace prever un direccionamiento más efectivo para los permanentes desafíos sociales, económicos y ambientales del siglo XXI

    A fiber-optic strain measurement and quench localization system for use in superconducting accelerator dipole magnets

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    A novel fiber-optic measurement system for superconducting accelerator magnets is described. The principal component is an extrinsic Fabry-Perot interferometer to determine localized strain and stress in coil windings. The system can be used either as a sensitive relative strain measurement system or as an absolute strain detector. Combined, one can monitor the mechanical behaviour of the magnet system over time during construction, long time storage and operation. The sensing mechanism is described, together with various tests in laboratory environments. The test results of a multichannel test matrix to be incorporated first in the dummy coils and then in the final version of a 13 T Nb/sub 3/Sn accelerator dipole magnet are presented. Finally, the possible use of this system as a quench localization system is proposed
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