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As a Covid Hub in Emilia Romagna, we have experienced an increasing number of tracheostomized patients, prompting us to develop a standardized decannulation protocol for COVID-19 ARDS patients. Currently, there are no guidelines or protocols for decannulation in this population, and few studies have investigated the early outcomes of tracheostomy in COVID-19 patients, with no detailed analysis of the decannulation process. We recognized the importance of mutual reliance among our team members and the significant achievements we made compared to previous decannulation methods. Through the optimization of the decannulation process, we identified a clear, safe, and repeatable method based on clinical best practice and literature evidence. We decided to implement an existing standardized decannulation protocol, which was originally designed for severe brain-damaged patients, due to the growing number of COVID-19 patients with tracheostomy. This protocol was designed for daily practice and aimed to provide a uniform approach to using devices like fenestrated cannulas, speaking valves, and capping. The results of our implementation include: expanding the applicability of the protocol beyond severe brain-damaged patients to different populations and settings (in this case, patients subjected to a long period of sedation and invasive ventilation) early activation of speech therapy to facilitate weaning from the cannula and recovery of physiological swallowing and phonation early activation of otolaryngologist evaluation to identify organic problems related to prolonged intubation, tracheostomy, and ventilation and address proper speech therapy treatment activation of more fluid and effective management paths for decannulation with a multiprofessional team.

The Covid-19 pandemic affected large part of Italy since February 2020; we, therefore, aimed to assess the impact of 2020 SARS-CoV-2 outbreak on telemedicine management of cardiovascular disease (CVD) in Italy. We analyzed data from three telemedicine dispatch centers, one located in Genoa, serving private clients (pharmacies, general practitioners), one in Brescia, serving pharmacies, and one in Bari, serving regional public STEMI network and emergency medical service in Apulia (4 million inhabitants). Demographic data and principal electrocardiogram diagnosis were collected and analyzed. Records from the time interval March 1, 2020 and April 1, 2020 were compared with the corresponding period in 2019. The comparative analysis of data shows a 54% reduction of telemedicine electrocardiogram transmission in Genoa telemedicine center (from 364 to 166), 68% in Brescia (from 5.745 to 1.905), 24% in Bari (from 15.825 to 11.716); relative reduction according to electrocardiogram diagnosis was 38% for acute coronary syndrome, 40% for other acute CVD in Genoa center, 24% for acute coronary syndrome, and 38% for other acute CVD in Bari. Male/female ratio remained substantially unchanged. A dramatic reduction of telemedicine access for CVD was observed during Covid-19 outbreak in March 2020 in Italy. The reduction was substantially consistent for all electrocardiogram findings, ACS, other acute CVD and normal.

BackgroundThe aim of this study was to assess by a census supported by the Italian Society of Cardiology (Società Italiana di Cardiologia, SIC) the present implementation of telemedicine in the field of cardiovascular disease in Italy.MethodsA dedicated questionnaire was sent by email to all the members of the SIC: data on telemedicine providers, service provided, reimbursement, funding and organisational solutions were collected and analysed.ResultsReported telemedicine activities were mostly stable and public hospital based, focused on acute cardiovascular disease and prehospital triage of suspected acute myocardial infarction (prehospital ECG, always interpreted by a cardiologist and not automatically reported by computerised algorithms). Private companies delivering telemedicine services in cardiology (ECGs, ambulatory ECG monitoring) were also present. In 16% of cases, ECGs were also delivered through pharmacies or general practitioners. ICD/CRT-D remote control was performed in 42% of cases, heart failure patient remote monitoring in 37% (21% vital parameters monitoring, 32% nurse telephone monitoring). Telemedicine service was public in 74% of cases, paid by the patient in 26%. About half of telemedicine service received no funding, 17% received State and/or European Union funding.ConclusionsSeveral telemedicine activities have been reported for the management of acute and chronic cardiovascular disease in Italy. The whole continuum of cardiovascular disease is covered by telemedicine solutions. A periodic census may be useful to assess the implementation of guidelines recommendations on telemedicine.

The electronic Health Bubble, from now on eHB, was conceived 24 months ago as an eHealth information and communication technology system whose aim is to help the telehealth and tele-caregiving services dedicated to elders or to patients affected by a chronic disease Thanks to our cooperation with experts of health services and consultants for other NHSs, the eHB field of intervention has been enlarged by including all the tools, equipment, medical processes and a new social approach to cope with the second phase of the COVID-19 pandemia, after the lockdown © 2020 The Authors

Escala de Apertura hacia el Futuro. (DOCX 16 kb)

Openness to the future Scale. (DOCX 22 kb)

The objective of this study was to derive normal electrocardiographic values and to report the abnormal findings in a large contemporary European cohort of physically active children and young adolescents. In a 3-month period, data derived from subjects aged between 3 and 14 years and referred to the Telecardiology Centre (Genoa, Italy) for electrocardiogram (ECG) evaluation as pre-participation screening for non-competitive sports were analyzed. A total of 2060 ECGs were recorded. Of those, 1962 did not show any morphological abnormality and were used to derive normality ranges for heart rate, PR interval, QRS duration, corrected QT interval, and voltage of R wave as measured in V1 according to age and sex. Findings and clinical implications of the 98 ECGs with abnormal findings were also reported. Abnormal ECG findings were not as uncommon as expected in this population, being manifest in about 5 % of subjects. However, major ECG anomalies (diffuse negative T-waves, pre-excitation) were present in just ten subjects (0.5 %). Lower mean heart rate values (from 90–100 bpm at 3 years of age to 80–85 bpm at 14 years of age) and lower rates of the prevalence of negative T-waves in the V3 lead (from 55–60 % at 3 years of age to 8–10 % at 14 years of age) were observed with increasing age. This is the first work reporting derived normal limits and abnormal ECG findings in a large contemporary European cohort of children and adolescents aged 3–14 years practicing non-competitive sports. Clear pathological alterations are extremely uncommon, deserving, when encountered, additional examinations. Even in a physically active population, the common features of an adult athlete’s ECG are absent.

We examined the interaction between ephrins and metabotropic glutamate (mGlu) receptors in the developing brain and cultured neurons. EphrinB2 coimmunoprecipitated with mGlu1a receptors, in all of the brain regions examined, and with mGlu5 receptors in the corpus striatum. In striatal slices, activation of ephrinB2 by a clustered form of its target receptor, EphB1, amplified the mGlu receptor-mediated stimulation of polyphosphoinositide (PI) hydrolysis. This effect was abolished in slices treated with mGlu1 or NMDA receptor antagonists but was not affected by pharmacological blockade of mGlu5 receptors. An interaction among ephrinB2, mGlu1 receptor, and NMDA was supported by the following observations: (1) the NR1 subunit of NMDA receptors coimmunoprecipitated with mGlu1a receptors and ephrinB2 in striatal lysates; (2) clustered EphB1 amplified excitatory amino acid-stimulated PI hydrolysis in cultured granule cells grown under conditions that favored the expression of mGlu1a receptors; and (3) clustered EphB1 amplified the enhancing effect of mGlu receptor agonists on NMDA toxicity in cortical cultures, and its action was sensitive to mGlu1 receptor antagonists. Finally, fluorescence resonance energy transfer and coclustering analysis in human embryonic kidney 293 cells excluded a physical interaction between ephrinB2 and mGlu1a (or mGlu5 receptors). A functional interaction between ephrinB and mGlu1 receptors, which likely involves adaptor or scaffolding proteins, might have an important role in the regulation of developmental plasticity.

Objective: To assess the feasibility of using contrast enhanced colour Doppler echocardiography to determine left ventricular (LV) mass and to compare its accuracy with LV mass obtained by magnetic resonance imaging (MRI). Methods: Images were acquired in the short axis plane of the heart, derived from coronal and sagittal scout views and double oblique angulation. The LV mass was calculated by two methods: Simpson’s rule and the area–length method. Levovist (Schering AG, Berlin, Germany) 2.5 g was given by slow intravenous bolus or infusion over about 45 seconds for contrast imaging. LV images were captured in the apical two chamber, four chamber, and three chamber views. Each contrast harmonic colour Doppler image was converted to a cavity-only image by simple image mathematics. Results: 27 (77.1%) of the patients (mean (SD) age 66.2 (8.9) years) were men. There was a mean (SD) interval of 6.6 (8.6) days (range 0–27 days) between echocardiography and MRI. The mean (SD) LV mass determined by MRI Simpson’s rule method was 171.0 (52.4) g (range 105.1–318.7 g). The mean LV mass (SD) determined by the echocardiographic Simpson’s rule method was 178.2 (47.0) g (range 112.6–307.6 g). The mean (SD) MRI area–length LV mass was 187.3 (64.5) g (range 109.0–393.6 g). The linear regression correlation between LV mass determined by MRI Simpson’s and echocardiographic Simpson’s methods was excellent (y = 1.022x, R 2 = 0.986) with a mean (SD) difference of 7.20 (20.9) g. The linear regression correlation between the MRI area–length LV mass and MRI Simpson’s LV mass was excellent (y = 1.101x, R 2 = 0.989) with a mean (SD) difference of 16.3 (22.3) g. Conclusions: LV mass may be obtained reliably by contrast enhanced colour Doppler and two dimensional echocardiography. The contrast Doppler method accurately determines LV mass with excellent agreement with the MRI technique.

The Large Hadron Collider (LHC) nominal luminosity is 10 34 cm −2 s −1 , but special runs at 10 28 cm −2 s −1 are also foreseen. In order to cover a luminosity dynamic range of six orders of magnitude, we have studied a new concept of luminosity monitor based on a double mode detector, working as a secondary emission counter at the highest luminosity and as an ionisation chamber at lower levels. We present the description of the device and the results obtained during tests at the CERN PS and SPS beams.

Cor triatriatum sinistrum is a rare congenital heart disease usually diagnosed in symptomatic children. Symptoms depend on the degree of obstruction to pulmonary venous return with pulmonary hypertension and other associated abnormalities. Persistent left superior vena cava is quite a common congenital heart disease (about 0.5% in healthy populations). It should be suspected every time a dilated coronary sinus is detected at the echo examination. Transthoracic and transoesophageal examinations visualize the site and the size of the fibrous membrane as well as the degree of obstruction, and allow the evaluation of pulmonary pressures that are very important clues for prognosis and therapy. This case report describes the clinical signs and the diagnostic ultrasound findings evaluated in comparison with magnetic resonance imaging, a well-defined gold standard in heart disease of this uncommon congenital association.

Telemedicine is the provision of health care services, through the use of information and communication technology, in situations where the health care professional and the patient, or 2 health care professionals, are not in the same location. It involves the secure transmission of medical data and information, through text, sound, images, or other forms needed for the prevention, diagnosis, treatment, and follow-up of a patient. First data on implementation of telemedicine for the diagnosis and treatment of acute myocardial infarction date from more than 10 years ago. Telemedicine has a potential broad application to the cardiovascular disease continuum and in many branches of cardiology, at least including heart failure, ischemic heart disease and arrhythmias. Telemedicine might have an important role as part of a strategy for the delivery of effective health care for patients with cardiovascular disease. In this document the Working Group on Telecardiology and Informatics of the Italian Society of Cardiology intends to remark some key-points regarding potential benefit achievable with the implementation of telemedicine support in the continuum of cardiovascular disease.

OBJECTIVES The purpose of this study was to verify in a long-term follow-up whether frequent monomorphic right ventricle extrasystoles may progress to arrhythmogenic right ventricular dysplasia (ARVD). BACKGROUND Frequent monomorphic right ventricle extrasystoles are generally considered benign. However, in patients with this pattern, cardiac magnetic resonance (MR) has recently shown anatomical and functional abnormalities of the right ventricle. METHODS Sixty-one patients who had been classified by noninvasive examinations as having frequent idiopathic right ventricle ectopy were contacted after 15 ± 2 years (12 to 20) and submitted to clinical examination, electrocardiogram (ECG), Holter monitoring, stress test, signal averaged ECG, echocardiography and, in 11 patients, cardiac MR. The primary end point was to ascertain the presence of cases of sudden death or progression to ARVD. RESULTS At the end of the follow-up, 55 patients were alive; six died, none of sudden death; eight stated to be well but refused further examinations. The 47 patients examined had normal ECG; in 24 patients (51%), extrasystoles were no longer present at Holter monitoring; late potentials were present in up to 15% of the patients; the right ventricle was normal at echocardiography. In 8 of 11 patients (73%), cardiac MR showed focal fatty replacement and other abnormalities of the right ventricle. CONCLUSIONS In this long-term follow-up study, no patient died of sudden death nor developed ARVD; two-thirds of the patients were asymptomatic, and, in half of the patients, ectopy had disappeared. Focal fatty replacement in the right ventricle was present in most.

This paper gives an overview of some stochastic optimization strategies, namely, evolution strategies, genetic algorithms, and simulated annealing, and how these methods can be applied to problems in electrical engineering. Since these methods usually require a careful tuning of the parameters which control the behavior of the strategies (strategy parameters), significant features of the algorithms implemented by the authors are presented. An analytical comparison among them is performed. Finally, results are discussed on three optimization problems.

To prepare dense bunches of lead ions for the LHC it has been proposed to accumulate the 4.2 MeV/u linac beam in a storage ring with electron cooling. A series of experiments is being performed in the low-energy ring LEAR to test this technique. First results were already reported at the Beam Crystallisation Workshop in Erice in November 1995. Two more recent runs to complement these investigations were concerned with: further study of the beam lifetime; the dependence of the cooling time on optical settings of the storage ring and on neutralization of the electron beam; and tests in view of multiturn injection. New results obtained in these two runs in December 1995 and in April 1996 will be discussed in this contribution.

A proposal for benchmark problems to test electromagnetic optimization methods, relevant to multiobjective optimization of a solenoidal superconducting magnetic energy storage with active and passive shielding is presented. The system has been optimized by means of different optimization procedures based on the global search algorithm, evolution strategies, simulated annealing and the conjugate gradient method, all coupled to integral or finite element codes. A comparison of results is performed and the features of the problem as a test of optimization procedures are discussed.

The authors present a vector environment, built around a reconfigurable data structure and a library of solver routines, devised for an efficient exploitation of vector features of computers to speed up magnetic analysis codes. The tests performed for the definition of the environment are reported and commented on, and the final results showing significant speedups in real magnetic analysis cases on a selected vector machine are presented and discussed. It is concluded that the use of the vector environment defined by the ITPLUS storage and the APPEAL library of solver routines has proven practical and successful as a way to allow users to efficiently exploit vector architectures, while protecting them from the need of large recoding efforts and of deep knowledge in computer architecture features and performances. >

A comparative evaluation of the quality of three different error estimation procedures used as refinement indicators and final error estimators is presented. The performance of each method, based on an element-by-element h-refinement technique, is assessed in a test case provided with an analytical solution, in a uniform environment. >

In recent years, the major emphasis of CIM research and development activity has been in the area of automated manufacturing, where technical and economic feasibility is critical for a viable CIM environment. However, to achieve a truly integrated manufacturing environment, it is necessary to integrate design activities into the structure. Although computers have been used for many years in the design process the present situation is not satisfactory, particularly for small and medium-sized industries. In most cases, computer-aided drafting tools are provided, but they are seldom integrated into the design process and the dependent analysis tools are still only available via separate and frequently unrelated analysis codes. Possible ways of improving the situation are discussed: these include improving the robustness of analysis codes by error estimation, adaptive meshing and postprocessing features, and providing an effective integrated environment, with drafting and design tools.

The present and possible future trends in development of computer hardware and system software for computer-intensive applications of computer-aided analysis and design are analyzed. An overview of the emerging products in each class of computers is presented, the authors' view of prospects of development of hardware and software products of interest to the CAD market is given, and hints for performance evaluation are provided. Finally, the present status of massively parallel computers is described, with emphasis on the architectures of interest for CAD applications. >

A comparative evaluation of the performance of adaptive meshing algorithms with different error estimators is presented. The algorithms are oriented toward electric and magnetic analysis applications. The performance of a selected set of algorithms that are based on an element-by-element h-refinement technique is assessed in some test cases in comparison with analytical results, in a uniform environment. Finally, the features of the various possible error estimation parameters are presented and discussed. >

For the LHC dipoles , mandatory electrical integrity tests are performed to qualify the cold mass (CM) at four production stages: individual pole, collared coil, CM before end cover welding and final CM. A description of the measurement equipment and its recent development are presented. After passing the demands set out in the specification, the results of the tests are transmitted to CERN where they are further analyzed. The paper presents the most important results of these measurements. We also report a review of the electrical nonconformities encountered e.g. inter-turn shorts and quench heater failure, their diagnostic and the cures

C. Santoni, coll. Atlas, To be published in the proceeding of the conference.; During the construction of the LHC main dipoles, 12 cases of short circuits between the cables of the superconducting coils have been detected. Some of them appeared only under the press, making impossible their localization after disassembly. In this paper we describe a method to locate electrical shorts through the use of room temperature magnetic measurements. An example case is discussed in detail to illustrate the features of the approach, and a statistic of the cases met during the production of more that 70% of the dipole total quantity is presented.

The problem of global optimization of magnetic structures composed of solenoids is examined, using a modified simulated annealing algorithm able to deal with the functions of continuous and/or discrete variables. The algorithm is tested using a discrete problem which allows determination of the cost function for every possible configuration of the system, providing information about the pattern of the cost function with respect to design variables. Despite the difficulty of minimizing the function, the proposed algorithm was able to locate the global minimum, or a point where the cost function has a value very close to it, seven times out of a total of ten runs. The algorithm is described, and results are discussed. >

The LHC ring will contain 1232 main dipole and 382 main quadrupole twin aperture magnets. All main magnets are superconducting and employ NbTi/Cu Rutherford type cables operated at 1.9 K. The dipole production has reached the equivalent of almost three octants of cold masses and nearly four octants of collared coils. The quadrupole production has reached 75 cold masses and over 150 bare magnets. The ramping up of large scale magnet production has posed several challenges which will be discussed, like: the coil size uniformity, coil pre-stress control, cold mass welding technique and the geometrical shape issues. The magnetic measurement results at warm will be presented together with their usage for the quality control in the production. The common features and differences of the three dipole producers will be discussed. Finally the latest version of the production schedule will be presented.

The LEAR electron cooler uses dense electron beams. Because of this high density the large space-charge potential induces significant drawbacks for the cooling process itself. As a consequence a space-charge neutralisation system has been implemented on the cooler. It consists of two positively polarised pairs of electrodes, placed on the outside of the drift space, which aim to store the ionised positive ions of charge Z. The major difficulty arises in the neutralisation instabilities. This paper reports on the technological aspects, the measurement techniques and the results.

Group A streptococci (GAS) specifically attach to and internalize into human epithelial host cells. In some GAS isolates, fibronectin-binding proteins were identified as being responsible for these virulence traits. In the present study, the previously identified global negative regulator Nra was shown to control the binding of soluble fibronectin probably via regulation of protein F2 and/or SfbII expression in the serotype M49 strain 591. According to results from a conventional invasion assay based on the recovery of viable intracellular bacteria, the increased fibronectin binding did not affect bacterial adherence to HEp-2 epithelial cells, but was associated with a reduction in the internalization rates. However, when examined by confocal and electron microscopy techniques, the nra-mutant bacteria were shown to exhibit higher adherence and internalization rates than the corresponding wild type. The mutant bacteria escaped from the phagocytic vacuoles much faster, promoting consistent morphological changes which resulted in severe host cell damage. The apoptotic and lytic processes observed in nra-mutant infected host cells were correlated with an increased expression of the genes encoding superantigen SpeA, the cysteine protease SpeB, and streptolysin S in the nra-mutant bacteria. Adherence and internalization rates of a nra/speB-double mutant at wild-type levels indicated that the altered speB expression in the nra mutant contributed to the observed changes in both processes. The Nra-dependent effects on bacterial virulence were confined to infections carried out with stationary growth phase bacteria. In conclusion, the obtained results demonstrated that the global GAS regulator Nra modulates virulence genes, which are involved in host cell damage. Thus, by helping to achieve a critical balance of virulence factor expression that avoids the injury of target cells, Nra may facilitate GAS persistence in a safe intracellular niche.

The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320 and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained., 18 pages, Latex, 9 .eps figures

The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is parameterized by a power law. Below the geomagnetic cutoff a substantial second spectrum was observed concentrated at equatorial latitudes with a flux ~ 70 m^-2 sec^-1 sr^-1. Most of these second spectrum protons follow a complicated trajectory and originate from a restricted geographic region., 19 pages, Latex, 7 .eps figures

To reach the design luminosity for lead-ions in the LHC, the present Low-Energy Antiproton Ring (LEAR) has to be converted into a Low-Energy Ion Ring (LEIR). Since the present ECR lead-ion source does not provide sufficient intensity, the main goal of LEIR is to act as a low-energy (4.2 MeV/u) accumulator where the ion beam is stacked and cooled (with the help of an electron-cooler) to reach the required intensity and emittances. An experimental program has been carried out at LEAR in recent years in order to test the cooling and stacking process with the present electron-cooler. A variety of results have been reported at previous conferences. This paper will focus on the electron-cooling aspects resulting from the afore mentioned experiments. Taking into account the experience gained, some guidelines will be given concerning the future LEIR machine and the electron-cooling device(s) that will be needed to produce cold dense electron beams.

The present paper discusses a technique, based on the combined use of Radial Basis Functions (RBF), which provide an analytical approximation of the true cost function, and self adaptive fuzzy sets, which allow a flexible combination of conflicting objectives, for the stochastic optimisation of multiminima problems. The proposed technique is fully described, its features of interest for industrial level design optimisation are outlined and some initial positive results are presented.

The LEAR machine is foreseen to be used as a lead ion accumulator in the injector chain for the LHC. Therefore, to test the principle of Pb54+ ion accumulation in LEAR, at 4.2 MeV/u, a number of studies and experiments have been made aimed at determining the improvements and modifications necessary to fulfill the LHC requirements. Amongst subjects studied we have investigated: a) The ion production and the injection line matching, b) The linac energy ramping in view of accumulation through combined longitudinal-transverse multi-turn injection, c) The ion beam lifetime and recombination processes, and finally d) The electron cooling time, as a function of the lattice parameters at the cooler. Recent experiments and measurements will be reported and commented in this paper. Also mentioned are some particular diagnostic methods.

Results from a European collaborative project to create an open system for engineering design, with particular emphasis toward electromagnetic devices, are presented. The system, code named MIDAS, is based on the new ISO STEP standard for data exchange and utilises state-of-the-art graphical user interfaces, 3D geometric modelling and three-dimensional automatic mesh generation with an advanced 2D subset.

By measuring the lifetime of stored beams, the recombination of the ions with cooling electrons was investigated. Rates found are larger than expected for radiative electron capture and significantly higher for Pb53+ than for Pb54+ and Pb52+. These results are important for the design of the lead ion injection system for the Large Hadron Collider and for recombination theories.

A new parallel global optimization algorithm is presented and evaluated. It is based on simulated annealing and on speculative computation. It is particularly suited for parallel architectures from some units to some tens of processors and for problems characterized by a cost function whose evaluation takes a long time, features that fit well with the design of magnetic structures. Comparative tests with respect to traditional sequential SA is presented on the design of a magnet for Magnetic Resonance Imaging. >

Several types of materials are frequently used for dental prostheses in dental medicine. Different treatments with titanium are the most used. The aim of the present study was to analyze by means of cytotoxicity and cytocompatibility techniques the capacity of dental implants to integrate to the bone tissue. Cultures of UMR 106 cell line derived from an osteosarcoma were used for bioassays mainly because they show many of the properties of osteoblasts. Dental implant samples provided by B&W company were compared with others of recognized trademarks. The first ones contain ASTM titanium (8348 GR2) with acid printing. Cytotoxicity was analyzed by means of lysosome activity, using the neutral red technique and alkaline phosphatase enzyme activity. Cell variability was determined by means of the acridine ethidium-orange bromide technique. One-way ANOVA and Bonferroni and Duncan post-ANOVA tests were used for the statistical analysis. The assays did not show significant differences among the dental implants analyzed. Our findings show that the dental prostheses studied present high biocompatibility, quantified by the bioassays performed. The techniques employed revealed that they can be a useful tool for the analysis of other materials for dental medicine use., Instituto Multidisciplinario de Biología Celular

The knowledge of the impregnation mechanism of porous solid insulation seems useful to ascertain the reaching of optimum insulating properties, but the problem has been scarcely dealt with in the literature, perhaps because of the high analytical difficulties resulting if a theoretical approach accounting for all the relevant phenomena is taken. A simplified mathematical model of pressboard monodimensional impregnation with transformer oil is presented, and a method for an experimental evaluation of model parameters is developed. Results of a set of experimental tests carried out by different methods and under different conditions are reported together with experimental tests of breakdown strength during impregnation, and a satisfactory agreement with the model previsions is noted. Finally, plots of approximate values of model parameters for different pressboards are given.

A cathode readout MWPC for the high-density projection chamber (HPC) of the DELPHI experiment at LEP has been built and tested. In order to decouple both electrically and mechanically the drift volume of the HPC from the readout region, the segmented cathodes are made of brass U profiles, with a 100 μm diameter wire wound around the profile with a 2 mm pitch.

It has been pointed out by several authors that the influence of impurity particles on dielectric phenomena in non-solid dielectrics can be significant in some cases, especially for technical liquids. In order to get information on such impurity influence, a computer-aided study of the motion of a charged spherical particle under general transient conditions, and with unrestricted conductivity and permittivity of both the medium and the particle has been carried out. To verify the model consistency, a set of tests in n-hexane with sphere-plane electrode geometry have been carried out using different experimental techniques, including high-speed-photography, and satisfactory agreement has been observed. On this basis, a model of the low-field conduction process by impurity particles has been developed assuming negligeable interactions between particles. A computer-aided procedure for the evaluation of impurity convection currents under different conditions has been implemented. The results obtained are compared with tests carried out on n-hexane with controlled pollution. Finally, a detailed discussion of the results obtained is given.

The new version of the package COMPELL (rev. 2.0) is designed to extend to the finite element method the generalized data input already present in the finite difference version (rev. 1.0). The algorithm used is based on the Galerkin method, generalized to allow the discretization of any system of partial differential equations. In the package the procedure is designed only for plane or axisymmetrical second order partial differential equations under nonlinear time-varying conditions; the extension to higher order equations is straightforward in principle.

The problem of the accurate computation of thermo-electromagnetic stresses in a toroidal field coil for Tokamak machines will be an important task in the design of future high field Tokamak machines. The high value of flux density, and the pulsed current operation of these machines, imply critical working conditions and require a correct modelling of the thermal and electrical diffusion phenomena. In this paper are presented the thermo-electromagnetic model developed for this aim and the results obtained by implementing this model in the code COMPELL. These results are then used to derive input data for the structural analysis code, ANSYS, thus providing the means for a rather detailed analysis of the structure.

The most commonly used types of uniform-field electrodes for dielectric strength tests in dielectric liquids are briefly recalled and analyzed, and the most significant criteria for the design of electrodes for the above purpose are reviewed and discussed. A new kind of uniform field electrodes which seems to be more suitable than the usual ones in regards the above criteria, is then presented and the procedure for the design of electrodes of given gap and uniform field area is fully described. Finally, the results obtained in extensive series of tests performed with three sets of electrodes of different uniform field area are briefly reported and discussed.