A limited-streamer tube electron detector with high rejection power against pions

The problem of detecting electrons in the 0.5–4.0 GeV energy range, in the presence of a high pion background, has been studied using a new type of electromagnetic shower detector. Its structural properties and the main parameters are given, together with the basic results in terms of energy resolution and of rejection power against pion background. The optimization of this new instrument gives a pion rejection power of ～ 6 × 10^?4 for energy ? 1.2 GeV.     

The technical feasibility of biomass gasification for hydrogen production

Biomass gasification for energy or hydrogen production is a field in continuous evolution, due to the fact that biomass is a renewable and CO₂ neutral source. The ability to produce biomass-derived vehicle fuel on a large scale will help to reduce greenhouse gas and pollution, increase the security of European energy supplies, and enhance the use of renewable energy. The Värnamo Biomass Gassification Centre in Sweden is a unique plant and an important site for the development of innovative technologies for biomass transformation. At the moment, the Värnamo plant is the heart of the CHRISGAS European project, that aims to convert the produced gas for further upgrading to liquid fuels as dimethyl ether (DME), methanol or Fischer–Tropsch (F–T) derived diesel. The present work is an attempt to highlight the conditions for the reforming unit and the problems related to working with streams having high contents of sulphur and alkali metals.     

Technic of overlapping sphincter anal repair in the treatment of traumatic anal incontinence

Faecal incontinence is an important disabling symptom in the affected patients. Classically, we divide faecal incontinence in two main types: neurogenic faecal incontinence and traumatic anal incontinence. Traumatic anal incontinence is due to causes damaging sphincteric mechanism directly. The aim of the present study was to evaluate the outcome of overlapping sphincter anal repair procedure in the management of traumatic anal incontinence. To this end we studied 27 patients with traumatic anal incontinence who underwent an overlapping sphincter anal repair procedure according to the method described by Parks and McPartlin in 1971. Mean follow up was up three years and was based mainly both on clinical evaluation with anorectal exploration and manometric values carried out on a 6 monthly basis. When the outcome was evaluated in terms of faecal continence our date were similar to those reported by Parks and Fang. In the subjects studied we haven't reported any major complications apart from one case of abscess, one case of wound's infection and one case of stenosis which were efficaciously treated. Our findings supported the view that overlapping sphincter anal repair procedure is the surgical approach of choice in the patients with traumatic anal incontinence.     

CD40lbase: a database of CD40L gene mutations causing X-linked hyper-IgM syndrome

X-linked hyper-IgM syndrome (X-HIM) is an immunodeficiency caused by mutations in the gene encoding the CD40 ligand (CD40L). A database (CD40Lbase) of CD40L mutations has now been established, and the resultant information, together with other mutations reported elsewhere in the literature, is presented here.     

Modeling transverse motions of a drill bit for process understanding

A model for drill bit transverse motions is proposed that identifies process conditions affecting hole quality and helps in the interpretation of drilling signal patterns produced during the hole-making process. A two-dimensional model of a drill rotating in a hole with clearance is presented. The simulation results, drilling force signal patterns, and hole geometry were found to be in close agreement. Drill rotation speed, drill stiffness, structural damping, drill hole clearance, and amplitude modulation of the forces acting on the drill appear to have a significant effect on drill bit transverse motions and on hole quality.     

The US HDTV standard

This standard for digital high-definition television has been submitted to the Federal Communications Commission for its approval. Based as it is on the MPEG-2 video compression and transport protocol, multiple transmission formats, Dolby AC-3 digital audio, and vestigial sideband digital modulation, this HDTV system will supply the home with superb images and spectacular sound while also, as part of the National Information Infrastructure (NII), relaying digital data. An HDTV system employing multiple transmission formats, digital compression, packetization, and modulation techniques is a marked advance over current world television standards such as NTSC, PAL, or SECAM     

PWM rectifier with low DC voltage ripple for magnet supply

PWM (pulsewidth-modulated) bridge rectifiers with GTO switches are considered for application to particle acceleration magnet power supplies, where two-quadrant operation and extremely low DC current ripple are required. Different control strategies, with both preprogrammed and variable switching patterns, are examined and compared in view of optimization of the system performance. In particular, optimum digital PWM, multilevel delta modulation, and hybrid PWM/delta techniques are analyzed. The validity of the control methods is verified by simulation and experimental tests on a 60 kW prototype     

Tunable Dopants with Intrinsic Counterion Separation Reveal the Effects of Electron Affinity on Dopant Intercalation and Free Carrier Production in Sequentially Doped Conjugated Polymer Films

Carrier mobility in doped conjugated polymers is limited by Coulomb interactions with dopant counterions. This complicates studying the effect of the dopant's oxidation potential on carrier generation because different dopants have different Coulomb interactions with polarons on the polymer backbone. Here, dodecaborane (DDB)‐based dopants are used, which electrostatically shield counterions from carriers and have tunable redox potentials at constant size and shape. DDB dopants produce mobile carriers due to spatial separation of the counterion, and those with greater energetic offsets produce more carriers. Neutron reflectometry indicates that dopant infiltration into conjugated polymer films is redox‐potential‐driven. Remarkably, X‐ray scattering shows that despite their large 2‐nm size, DDBs intercalate into the crystalline polymer lamellae like small molecules, indicating that this is the preferred location for dopants of any size. These findings elucidate why doping conjugated polymers usually produces integer, rather than partial charge transfer: dopant counterions effectively intercalate into the lamellae, far from the polarons on the polymer backbone. Finally, it is shown that the IR spectrum provides a simple way to determine polaron mobility. Overall, higher oxidation potentials lead to higher doping efficiencies, with values reaching 100% for driving forces sufficient to dope poorly crystalline regions of the film.