Experience with the Quality Assurance of the Superconducting Electrical Circuits of the LHC Machine

The coherence between the powering reference database for the LHC and the Electrical Quality Assurance (ELQA) is guaranteed on the procedural level. However, a challenge remains the coherence between the database, the magnet test and assembly procedures, and the connection of all superconducting circuits in the LHC machine. In this paper, the methods, tooling, and procedures for the ELQA during the assembly phase of the LHC will be presented in view of the practical experience gained in the LHC tunnel. Some examples of detected polarity errors and electrical non-conformities will be presented. The parameters measured at ambient temperature, such as the dielectric insulation of circuits, will be discussed

Automatic System for the D.C. High Voltage Qualification of the Superconducting Electrical Circuits of the LHC Machine

A d.c. high voltage test system has been developed to verify automatically the insulation resistance of the powering circuits of the LHC. In the most complex case, up to 72 circuits share the same volume inside cryogenic lines. Each circuit can have an insulation fault versus any other circuit or versus ground. The system is able to connect up to 80 circuits and apply a voltage up to 2 kV D.C. The leakage current flowing through each circuit is measured within a range of 1 nA to 1.6 mA. The matrix of measurements allows characterizing the paths taken by the currents and locating weak points of the insulation between circuits. The system is composed of a D.C. voltage source and a data acquisition card. The card is able to measure with precision currents and voltages and to drive up to 5 high voltage switching modules offering 16 channels each. A LabVIEW application controls the system for an automatic and safe operation. This paper describes the hardware and software design, the testing methodology and the results obtained during the qualification of the LHC superconducting circuits

The Quality Control of the LHC Continuous Cryostat Interconnections

The interconnections between the Large Hadron Collider (LHC) magnets have required some 40 000 TIG welded joints and 65 000 electrical splices. At the level of single joints and splices, non-destructive techniques find limited application: quality control is based on the qualification of the process and of operators, on the recording of production parameters and on production samples. Visual inspection and process audits were the main techniques used. At the level of an extended chain of joints and splices - from a 53.5 m half-cell to a complete 2.7 km arc sector - quality control is based on vacuum leak tests, electrical tests and RF microwave reflectometry that progressively validated the work performed. Subsequent pressure tests, cryogenic circuits flushing with high pressure helium and cool-downs revealed a few unseen or new defects. This paper presents an overview of the quality control techniques used, seeking lessons applicable to similar large, complex projects

Electrical Quality Assurance of the Superconducting Circuits during LHC Machine Assembly

Based on the LHC powering reference database, all-together 1750 superconducting circuits were connected in the various cryogenic transfer lines of the LHC machine. Testing the continuity, magnet polarity, and the quality of the electrical insulation were the main tasks of the Electrical Quality Assurance (ELQA) activities during the LHC machine assembly. With the assembly of the LHC now complete, the paper reviews the work flow, resources, and the qualification results including the different types of electrical non-conformities

The LHC Continuous Cryostat Interconnections: The Organization of a Logistically Complex Worksite Requiring Strict Quality Standards and High Output

The interconnections of the Large Hadron Collider (LHC) continuous cryostat have been completed in fall 2007: 1695 interconnections magnet to magnet and 224 interconnections between the continuous cryostat and the cryogenic distribution line have been executed along the 27 km of the LHC. The very tight schedule, the complexity of the interconnection sequence, the strict quality standards applied have required the creation of an ad hoc organization in order to steer and coordinate the activities on the worksite dispersed along the whole accelerator ring. The concatenation of construction and test phases carried out by CERN staff, CERN collaborating institutes and contractors have led to the necessity of a common approach and of a very effective information flow. In this paper, after having recalled the main technical challenges, we review the organizational choices that have been taken and we briefly analyze the development of the worksite in term of allocated resources and production

cardiovascular risk factors and sympatho vagal balance importance of time domain heart rate variability

Objective: Cardiovascular Disease (CVD) is the leading cause of death and disability worldwide. sDyregulation of the autonomic nervous system associated with various pathological conditions often occurs in presence of cardiovascular risk factors. Heart Rate Variability (HRV) may be used to assess autonomic imbalances. The aim of our study is to evaluate the correlation between HRV and the main cardiovascular risk factors in subject who underwent digital ambulatory 24 hours Holter ECG monitoring for clinical investigations. Methods: We evaluated time domain parameters of HRV by Holter ECG monitoring in a large population categorized based on the presence or absence of the major cardiovascular risk factors. Results: We found significant differences in time domain parameters of HRV in patients with and without common risk factor for CVD such as diabetes, family history for Coronary Artery Disease and dyslipidemia. We also analyzed our study population based on age and we found a positive correlation with the standard deviation of all NN intervals (SDNN), square root of the mean of the sum of the square of the differences between adjacent NN intervals (RMSSD), mean R-R intervals and by the number of adjacent NN intervals differing by more than 50 ms divided by the total number of all NN intervals (pNN50) and an inverse correlation for the others parameters. Conclusion: Non-modifiable risk factors (age, gender, family history) along with dyslipidemia and diabetes, are related to a change in HRV, while modifiable risk factors (smoking, hypertension, overweight, hyperhomocysteinemia) showed no correlation. This would seem to indicate that the genetic components more than lifestyle habits and behavior act on the nervous control of the heart. Our study shows the possibility to find interesting clinical-prognostic data, analyzing simple parameters obtained from instrumental methods of investigation performed for other clinical reasons

Integration of an Autothermal Outer Electrified Reformer Technology for Methanol Production from Biogas: Enhanced Syngas Quality Production and CO2 Capture and Utilization Assessment

Biogas has emerged as a valid feedstock for biomethanol production from steam reforming. This study investigates an alternative layout based on an auto-thermal electrified reforming assuming a 1 MW equivalent anaerobic digestion plant as a source for methanol synthesis. The process considers an oxy-steam combustion of biogas and direct carbon sequestration with the presence of a reverse water–gas shift reactor to convert CO2 and H2 produced by a solid oxide electrolyzer cell to syngas. Thermal auto-sufficiency is ensured for the reverse water–gas shift reaction through the biogas oxy-combustion, and steam production is met with the integration of heat network recovery, with an overall process total electrical demand. This work compares the proposed process of electrification with standard biogas reforming and data available from the literature. To compare the results, some key performance indicators have been introduced, showing a carbon impact of only 0.04 kgCO2/kgMeOH for the electrified process compared to 1.38 kgCO2/kgMeOH in the case of biogas reforming technology. The auto-thermal electrified design allows for the recovery of 66.32% of the carbon available in the biogas, while a similar electrified process for syngas production reported in literature reaches only 15.34%. The overall energy impact of the simulated scenarios shows 94% of the total energy demand for the auto-thermal scenario associated with the electrolyzer. Finally, the introduction of the new layout is taken into consideration based on the country’s carbon intensity, proving carbon neutrality for values lower than 75 gCO2/kWh and demonstrating the role of renewable energies in the industrial application of the process

The impact of ventral oral graft bulbar urethroplasty on sexual life

Objective: To evaluate the pre- and postoperative aspects of sexual life (SL) in patients with bulbar urethral stricture who underwent ventral oral graft urethroplasty. Methods: Between 2009 and 2010, 52 men (mean age 36 years) were enrolled in our prospective study to ascertain sexual disorders before and after surgery. The validated Male Sexual Health Questionnaire-Long Form (MSHQ-LF) was completed pre- and postoperatively; the unvalidated but adapted Post-Urethroplasty Sexual Questionnaire (PUSQ) was completed postoperatively. Data were compared using the non parametric Wilcoxon test. Results: Before urethroplasty, most of the patients reported sexual disorders, in particular reduced ejaculatory stream (85%); many of them (35%) feared the risk of a postoperative worsening in the quality of SL. After urethroplasty, nobody reported a worsened erection, while most of the patients noticed a significant improvement in erection, ejaculation, relationship with their partner, sexual activity, and desire. Modifications in the scrotoperineal sensitivity were reported by 42% and 15% noticed esthetic changes without impact on SL. All patients reported an improvement in quality of life (QOL) and were satisfied with the outcome of urethroplasty. Conclusion: Urethral stricture disease may be responsible for sexual disorders that have a significant impact upon SL. Patients confessed a marked anxiety tackling urethroplasty and declared that one of their deepest fears regarded a potential further deterioration in the quality of SL. At short-term follow-up, the minimally invasive ventral graft urethroplasty does not cause sexual complications, apart from the post-ejaculation dribbling. On the contrary, this technique showed to restore SL in all its aspects

A puzzling Mule Coin from the Parabita Hoard: a Material Characterisation

In this research, we report on the compositional, microstructural and crystallographic properties of a lead coin which has been regarded for many years as a genuine silver coin minted in the Southern Italy in the course of the 4th century BC. The material characterisation of this object allowed detecting an ancient forging technology, not previously reported, which was meant for the silvering of lead substrates The data collected have disclosed a contemporary counterfeiting procedure based on a metal coating process onto a Pb substrate. This coating has been identified as a bi-layer with a Cu innermost and an Ag outermost visible layer. As far as the coating application technique is concerned, the gathered evidence has clearly indicated that the original appearance of this artifact cannot be explained in terms of any of the established methods for the growth of an artificially silvered coating in classical antiquity. This technology is now being explained in terms of modern, fully non destructive scientific methods.Comment: 9 pages including 8 figures. To be presented at the Cavallino Archaeometry Workshop 2006, Cavallino (Lecce - Italy) - May 22-25, 200