The Assembly of the LHC Short Straight Sections at CERN: Work Organization, Quality Assurance and Lessons Learned

After 4 years of activity, the assembly of approximately 500 Short Straight Sections (SSS) for the LHC has come to an end at the beginning of 2007. This activity, which was initially foreseen in European industry, was in-sourced at CERN because of the insolvency of the prime contractor. While the quadrupole cold masses were produced in industry, the assembly within their cryostats was transferred to CERN and executed by an external company under a result-oriented contract. CERN procured cryostat components, set up a dedicated 2000 m2 assembly hall with all the specific assembly equipment and tooling and defined the assembly and testing procedures. The contractor took up responsibility for the delivery, on time, of assemblies according to the required quality. A dedicated CERN production and quality assurance team was constituted. A specific quality assurance plan was set up involving 2 additional contractors responsible for weld inspections on a total of about 20'000 assembly welds and the execution of about 3300 leak detection tests. This paper presents the organizational aspects of the activity and the experience gained throughout the production. The learning curves and statistics by type of non-conformities detected and general quality assurance aspects are presented and discussed. The main lessons learnt are summarized, in an attempt to draw some conclusions which could be useful in making strategic choices for the cryostat assembly in future large-scale accelerators

Determination of School Culture and Motivation on Learning Tourism Achievement

This study aims to determine the determination of school culture and achievement motivation on tourism learning achievement. This study is an ‘ex-post facto’ study with a sample size of 133 people. Data collection tool is a questionnaire and an observation sheet; data analysis was done with simple regression, multiple regression, and partial correlation. The results showed that: (1) there was a significant determination between school culture on learning achievement of Tourism with correlation coefficient of 0.205 and effective contribution of 7.24%; (2) there was a significant determinant between the learning discipline on the learning achievement of Tourism with a correlation coefficient of 0.320 and effective contribution of 11.28%; (3) there is a significant determination between achievement motivation to the learning achievement of Tourism with a correlation coefficient of 0.304 and effective contribution of 10.57%; and (4) together, there is a significant determinant between school culture, discipline of learning, and achievement motivation toward learning achievement of Tourism with double correlation coefficient equal to 0.539 and its contribution equal to 29.1% to learning achievement of Tourism class X SMK in Singaraja Town.     Keywords: school culture, achievement motivation, learning achievement Touris

Thermal Performance of the LHC Short Straight Section Cryostat

The LHC Short Straight Section (SSS) cryostat houses and thermally protects in vacuum the cold mass which contains a twin-aperture superconducting quadrupole magnet and superconducting corrector magnets operating at 1.9 K in superfluid helium. In addition to mechanical requirements, the cryostat is designed to minimize the heat in-leak from the ambient temperature to the cold mass. Mechanical components linking the cold mass to the vacuum vessel such as support posts and an insulation vacuum barrier are designed to have minimum heat conductivity with efficient thermalisations for heat interception. Heat in-leak by radiation is reduced by employing multilayer insulation wrapped around the cold mass and an actively cooled aluminium thermal shield. The recent commissioning and operation of two SSS prototypes in the LHC Test String 2 have given a first experimental validation of the thermal performance of the SSS cryostat in nominal operating conditions. Temperature sensors mounted in critical locations provide a temperature mapping which allows a crosscheck with the calculated temperature values and thermal performance. Moreover the measurements allowed a validation of the efficiency of the employed thermalisations. This paper presents the experimental results for the thermal performance of cryostat components and gives a first comparison with the design values

Evaluation of reproductive performances of the common octopus (Octopus vulgaris) reared in water recirculation systems and fed different diets

The reproductive performance of Octopus vulgaris broodstocks fed two different diets (mixed fish [F group, BW 1,048.14 g] or mixed crustaceans [C group, BW 998.44 g]) was analyzed using an experimental recirculating aquaculture system consisting of a tank equipped with spawning and incubation chambers. A total of 8 females (F1–4; C1–4), and 8 males (M1–M8) were selected. DI of the C group females was significantly (p < 0.05) higher (3.0 ± 0.29%) than the F group (2.16 ± 0.67%). SGR in C group was significantly higher (1.43 ± 0.12%) than the F group (1.18 ± 0.25%). Egg clusters, number of clusters, number of clusters/kg BW, and total length were more favorable in the C group than the F group. The number of clusters/kg BW of C females was 2.5 times higher than that of F females (78.1 ± 6.5 vs 31.1 ± 13.3). The total eggs number, number of eggs/cm, number of eggs/kg BW in the C group were significantly (p < 0.05) higher compared with the F group; the number of eggs/kg BW and paralarvae/kg BW were 5 times higher in the C group (115,928 ± 12,513 C vs 22,109 ± 7912 F and 114,953 ± 12,591 vs 20,729 ± 7104, respectively). Hatching rate of the C group was significantly (p < 0.05) higher compared to the F grou

Potencial de Pseudomonas sp. psicrotolerantes isoladas da Antártica no biocontrole de Botrytis cinerea.

Resumo: A Antártica, por ser um ambiente extremo, comporta micro-organismos que podem ter características interessantes, como crescimento a baixas temperaturas (psicrotolerância), além da produção de compostos antimicrobianos. Como também a possibilidade de aplicação desses micro-organismos no controle de fitopatogenos que se desenvolveu em baixas temperaturas, como é o caso de Botrytis cinerea, que ataca dezenas de culturas agrícolas em zonas temperadas. O morango, Fragaria vesca, é comumente atacado por este fungo, causando a doença conhecida como podridão cinzenta, principalmente durante a pós-colheita. Desta forma, o objetivo deste trabalho foi prospectar bactérias isoladas da Antártica e avaliar o potencial de inibição deste fitopatogeno. Assim foram testadas 56 bactérias sendo que 42% apresentaram melhor crescimento a 4°C. 4 dessas pertencentes ao gênero Pseudomonas, sendo que a linhagem 44-4 (Pseudomonas Syringae), foi capaz de controlar o desenvolvimento do fungo em morango (4°C). Demonstra-se, portanto, a possibilidade de prospecção de bactérias Psicrofilicas com potencial de reduzir o crescimento de fungos a baixa temperatura. Ensaios estão sendo feitos para elucidação dos compostos químicos responsáveis por este efeito. Abstract: Antarctica, being an extreme environment, includes micro-organisms that may have interesting features, such as growth at low temperatures (psicrotolerância), besides the production of antimicrobial compounds. As well as the possibility of application of these micro-organisms to control plant pathogens that developed at low temperatures, as is the case of Botrytis cinerea, attacking dozens of agricultural crops in temperate zones. The strawberry, Fragaria vesca, is commonly attacked by this fungus causing the disease known as gray mold, especially during post-harvest. Thus, the objective was to prospect for bacteria isolated from Antarctica and evaluate the potential inhibition of this pathogen. So were tested 56 bacteria and 42% showed better growth at 4°C. Four of these belonging to the genus Pseudomonas, and the line 44-4 (Pseudomonas syringae) was able to control the development of the fungus in strawberry (4°C). It is shown so the prospectivity of Psychrophilic bacteria with potential to reduce the fungal growth at low temperature. Tests are being made to elucidation of the chemical compounds responsible for this effect

Leak-Tight Welding Experience from the Industrial Assembly of the LHC Cryostats at CERN

The assembly of the approximately 1700 LHC main ring cryostats at CERN involved extensive welding of cryogenic lines and vacuum vessels. More than 6 km of welding requiring leak tightness to a rate better than 1.10-9 mbar.l.s-1 on stainless steel and aluminium piping and envelopes was made, essentially by manual welding but also making use of orbital welding machines. In order to fulfil the safety regulations related to pressure vessels and to comply with the leak-tightness requirements of the vacuum systems of the machine, welds were executed according to high qualification standards and following a severe quality assurance plan. Leak detection by He mass spectrometry was extensively used. Neon leak detection was used successfully to locate leaks in the presence of helium backgrounds. This paper presents the quality assurance strategy adopted for welds and leak detection. It presents the statistics of non-conformities on welds and leaks detected throughout the entire production and the advances in the use of alternative leak detection methods in an industrial environment

The Bologna Complete Sample of Nearby Radio Sources

We present a new, complete, sample of 95 radio sources selected from the B2 and 3CR catalogues, with z < 0.1. Since no selection effect on the core radio power, jet velocity, or source orientation is present, this sample is well suited for statistical studies. In this first paper we present the observational status of all sources on the parsec (mas) and kiloparsec (arcsec) scale; we give new parsec-scale data for 28 sources and discuss their parsec-scale properties. Combining these data with those in the literature, information on the parsec-scale morphology is available for a total of 53 radio sources with different radio power and kpc-scale morphology. We investigate their properties. We find a dramatically higher fraction of two-sided sources in comparison to previous flux limited VLBI surveys.Comment: 29 pages, 21 figures - ApJ in press (10 Jan 2005 issue