Design and construction of a 1 m model of the low current superconducting quadrupole for the LHC insertions

About one hundred individually powered low current superconducting quadrupoles will be installed in the LHC insertions. One of the design requirements was to keep the excitation current of the magnet below 6 kA in view of minimizing the costs of the powering circuits. The design of the quadrupole is based on a 8.2 mm NbTi cable, and is designed for a nominal gradient of 200 T/m at 1.9 K. In this paper we present the design of the quadrupole and discuss the construction details of the 1 m single aperture model which has been recently completed

Development of Superconducting Tuning Quadrupole Corrector (MQT) Prototypes for the LHC

The main quadrupoles of the Large Hadron Collider (LHC) are connected in families of focusing and defocusing magnets. In order to make tuning corrections in the machine a number of quadrupole corrector magnets (designated MQT) are necessary. These 56 mm diameter aperture magnets have to be compact, with a maximum length of 395 mm and a coil radial thickness of 5 to 7.5 mm, while generating a minimum field gradient of 110 T/m. Two design options have been explored, both using the "counter-winding" system developed at CERN for the fabrication of low cost corrector coils. The first design, with the poles composed of two double-pancake coils, each counter-wound using a single wire, superposed to create 4-layer coils, was developed and built by ACCEL Instruments GmbH. A second design where single coils were counter-wound using a 3-wire ribbon to obtain 6-layer coils was developed at CERN. This paper describes the two designs and reports on the performance of the prototypes during testing

Launching of Series Fabrication of the LHC Main Quadrupoles

A collaboration agreement between CERN and CEA-Saclay resulted in the successful development and construction of prototypes of the LHC main superconducting quadrupole magnets and their assembly into cold masses. A call for tender was issued in October 1999 and led to the adjudication of a contract to ACCEL Instruments. A number of components will be provided by CERN to be used either directly by ACCEL for integration into the cold mass units or by sub-suppliers before delivery to ACCEL. During the series fabrication CEA's engineers and technicians, already experienced from their prototype work, will ensure the technology transfer and the technical follow up in the factory. ACCEL had to adapt two large fabrication halls to the needs of the magnet fabrication and the cold mass assembly. Procedures for a tight quality assurance and the logistics for the timely supply of components and a high production rate are being established in close collaboration by the three parties concerned

Performance of the LHC Arc Superconducting Quadrupoles Towards the End of their Series Fabrication

The fabrication of the 408 main arc quadrupole magnets and their cold masses will come to an end in summer 2006. A rich collection of measurement and test data has been accumulated and their analysis is presented in this paper. These data cover the fabrication and the efficiency in the use of the main components, the geometrical measurements and the achieved dimensional precision, the warm magnetic measurements in the factory and the performance at cold conditions, especially the training behaviour. The scrap rate of the Nb-Ti/Cu conductor as well as that of other components turned out to be acceptably low and the quench performance measured was in general very good. Most quadrupoles measured so far exceeded the operating field gradient with one or no quench. The multipole content at cold was measured for a limited number of quadrupoles in order to verify the warm-to-cold correlation. From the point of view of field quality, all quadrupoles could be accepted for the machine. The measures taken to overcome the problem of a too high permeability of a batch of collars are discussed

System Acquisition Management: Exploring the Relationship Between Program and Contract Management Personnel at Air Force Product Centers

The purpose of this study was to test if relationship problems exist between program and contract management personnel working in system-level acquisition throughout Air Force Materiel Command (AFMC). We used a survey instrument to examine a representative sample of program and contract management personnel assigned to various product centers. A similar study was conducted at Aeronautical Systems Division in 1991. However, the survey instrument was inadequate for deriving certain results. Consequently, we improved upon he prior survey and obtained more definite findings. Survey results showed that most program and contract managers believe conflict exists, Also, six of the twelve independent variables studied, (confidence in counterparts, goal compatibility, value in counterparts, communication, travel, and role ambiguity) significantly contributed to the conflict model. Furthermore, matrixed organizations, program management courses not teaching how to deal with contract managers, and the acquisition process itself, were identified as possible conflict contributors, but were not included in the model. Recommendations for improving the program/ contract management relationships were subsequently offered to AFMC and suggestions for future research were given

Performance of the single and twin-aperture models of the 6 kA superconducting quadrupole for the LHC insertions

The LHC dispersion suppressors and matching sections will be equipped with individually powered superconducting quadrupoles with an aperture of 56 mm. In order to optimise the parameters and cost of the magnets and of their powering, the quadrupole has been designed on the basis of an 8.2 mm wide Rutherford-type cable for a nominal current of 5300 A, corresponding to a gradient of 200 T/m at 1.9 K. In order to validate the design two 1-m single-aperture quadrupoles and one twin-aperture quadrupole have been built and tested. In this report we describe the construction features of the magnets and present the results of the magnet tests. (4 refs)

Esteem in the sciences made visible: How bibliometry receives new impulse from social network analysis

The article intends to show how a way of combining methods of social network analysis with methods of classical bibliometry meaningfully may be applied within historical studies. Going beyond bibliometry the argument is supported that a set of driving forces which build relationships among scientific actors via scientific activities might be subsumed in the pluri-dimensional term ‘esteem’ (Anerkennung) which should be distinguished from pure reputation. The method of a historical reconstruction of scientific networks seems to be especially useful for representing esteem within the sciences and implementing it as a sort of “currency system“ or social capital in the sense of Pierre Bourdieu. The concept of network serves as an abstract model in this context. The history of eugenics is uses as an example for data collection, data processing, data visualization and data interpretation. Three textbooks (including translations) are selected for analysis, the German Erwin Baur, Eugen Fischer, Fritz Lenz, Grundriß der menschlichen Erblichkeitslehre und Rassenhygiene (1st ed. 1921); the US-American Charles Davenport, Heredity in Relation to Eugenics; and the Swedish Gunnar Dahlberg, Arv och Ras. The proposed approach shows not only differentiated picture of the structure of the reception of these works but also the shift of interest from a variety of fields of medical research to the history of sciences.The article intends to show how a way of combining methods of social network analysis with methods of classical bibliometry meaningfully may be applied within historical studies. Going beyond bibliometry the argument is supported that a set of driving forces which build relationships among scientific actors via scientific activities might be subsumed in the pluri-dimensional term ‘esteem’ (Anerkennung) which should be distinguished from pure reputation. The method of a historical reconstruction of scientific networks seems to be especially useful for representing esteem within the sciences and implementing it as a sort of “currency system“ or social capital in the sense of Pierre Bourdieu. The concept of network serves as an abstract model in this context. The history of eugenics is uses as an example for data collection, data processing, data visualization and data interpretation. Three textbooks (including translations) are selected for analysis, the German Erwin Baur, Eugen Fischer, Fritz Lenz, Grundriß der menschlichen Erblichkeitslehre und Rassenhygiene (1st ed. 1921); the US-American Charles Davenport, Heredity in Relation to Eugenics; and the Swedish Gunnar Dahlberg, Arv och Ras. The proposed approach shows not only differentiated picture of the structure of the reception of these works but also the shift of interest from a variety of fields of medical research to the history of sciences

Double blind, randomized, placebo controlled clinical trial for the treatment of diabetic foot ulcers, using a nitric oxide releasing patch: PATHON

<p>Abstract</p> <p>Background</p> <p>Diabetes Mellitus constitutes one of the most important public health problems due to its high prevalence and enormous social and economic consequences. Diabetic foot ulcers are one of the chronic complications of diabetes mellitus and constitute the most important cause of non-traumatic amputation of inferior limbs. It is estimated that 15% of the diabetic population will develop an ulcer sometime in their lives. Although novel therapies have been proposed, there is no effective treatment for this pathology. Naturally produced nitric oxide participates in the wound healing process by stimulating the synthesis of collagen, triggering the release of chemotactic cytokines, increasing blood vessels permeability, promoting angiogenic activity, stimulating the release of epidermical growth factors, and by interfering with the bacterial mitochondrial respiratory chain. Topically administered nitric oxide has demonstrated to be effective and safe for the treatment of chronic ulcers secondary to cutaneous leishmaniasis. However, due to their unstable nitric oxide release, the topical donors needed to be applied frequently, diminishing the adherence to the treatment. This difficulty has led to the development of a multilayer polymeric transdermal patch produced by electrospinning technique that guarantees a constant nitric oxide release. The main objective of this study is to evaluate the effectiveness and safety of this novel nitric oxide releasing wound dressing for the treatment of diabetic foot ulcers.</p> <p>Methods and design</p> <p>A double-blind, placebo-controlled clinical trial, including 100 diabetic patients was designed. At the time of enrollment, a complete medical evaluation and laboratory tests will be performed, and those patients who meet the inclusion criteria randomly assigned to one of two groups. Over the course of 90 days group 1 will receive active patches and group 2 placebo patches. The patients will be seen by the research group at least every two weeks until the healing of the ulcer or the end of the treatment. During each visit the healing process of the ulcer, the patient's health status and the presence of adverse events will be assessed. Should the effectiveness of the patches be demonstrated an alternative treatment would then be available to patients.</p> <p>Trial registration</p> <p>NCT00428727.</p