nils-herrmann/clean_scirepeval huggingface dataset:
Upgrade of the DIII-D vacuum vessel protection system

An upgrade of the General Atomics DIII-D tokamak armor protection system has been completed. The upgrade consisted of armoring the outer wall and the divertor gas baffle with monolithic graphite tiles and cleaning the existing floor, ceiling, and inner wall tiles to remove any deposited impurity layer from the tile surfaces. The new tiles replace the graphite tiles used as local armor for neutral beam shine through, three graphite poloidal back-up limiter bands, and miscellaneous Inconel protection tiles. The total number of tiles increased from 1636 to 3200 and corresponding vessel coverage from 40% to 90%. A new, graphite armored, toroidally continuous, gas baffle between the outer wall and the biased divertor ring was installed in order to accommodate the cryocondensation pump that was installed in parallel with the outer wall tiles. To eliminate a source of copper in the plasma, GRAFOIL gaskets replaced the copper felt metal gaskets previously used as a compliant heat transfer interface between the inertially cooled tiles and the vessel wall. GRAFOIL, an exfoliated, flexible graphite material from Union Carbide, Inc., was used between each tile and the vessel wall and also between each tile and its hold-down hardware. Testing was performed to determine the mechanical compliance, thermal conductance, and vacuum characteristics of the GRAFOIL material. To further decrease the quantity of high Z-materials exposed to the plasma, the 1636 existing graphite tiles were identified, removed, and grit blasted to eliminate a thin layer of deposited metals which included nickel, chromium, and molybdenum. Prior to any processing, a selected set of tiles was tested for radioactivity, including tritium contamination. The tiles were grit blasted in a negative-pressure blasting cabinet using 37 /spl mu/m boron carbide powder as the blast media and dry nitrogen as the propellant. A 30 to 50 /spl mu/m-thick layer was removed from the surfaces of each tile. The tiles were cleaned in an ultrasonic alcohol bath and vacuum baked to 1000/spl deg/C prior to reinstallation. The installation of the graphite armor and gas baffle and the grit blasting of the tiles was performed in August 1992 through January 1993. Initial operational experience with the new armor system is summarized.
Superconducting Feeder System for ITER Central Solenoid Module Final Test Facility

General Atomics has commissioned the final test facility at the central solenoid module (CSM) manufacturing site in Poway, CA, USA. The facility includes a number of critical subsystems including the feeder system (FS), supplied by the Institute of Plasma Physics Chinese Academy of Science (ASIPP), that connects the test chamber to the cryogenic and electrical systems. It includes a coil termination box, high-temperature superconducting current leads, and a feeder duct. The FS carries the current (50 kA) and supercritical helium (4.5 K, 5.5 bara) to the CSM and its supporting structure, while monitoring and controlling the temperature, pressure, flow, and voltage drop through all elements of the superconducting components. It functions as an integral part of the system to rapidly (6-s decay time) dissipates 1-GJ energy stored in the coils, and to protect the cryogenic system. The system is complex, requiring multidisciplinary engineering including: high-temperature superconductivity, cryogenic-temperatures (77, 50, and 4.5 K), high vacuum (1.0 × 10−5 Pa), redundant quench detection (voltage, temperature), high-voltage insulation (15 kV), low thermal loads (70 W), low electrical joint resistance (2 nΩ), Paschen testing, high-voltage signal measurements, and high-current electronics. The system presented significant challenges for design and analysis, complex manufacturing assembly processes, measurement and control, and stringent quality and safety requirements.
Cygnus performance on five Subcritical Experiments

The Cygnus Dual Beam Radiographic Facility includes two identical radiographic sources — Cygnus 1 and Cygnus 2. Cygnus is the radiography source used in Subcritical Experiments (SCEs) at the Nevada National Security Site (NNSS). The machine specifications are: Electric 2.25 MV, 60 kA, 60 ns; Radiation 4 Rad, 1 mm, 50 ns; Operation single shot, 2-shots/day. Cygnus has operated at the NNSS since February 2004. In this period, it has participated on five SCE experiments — Armando, Bacchus, Barolo A, Barolo B, and Pollux. SCE projects typically require over a hundred preparatory shots culminating in a single high-fidelity or SCE shot, and typically take over a year for completion. Therefore, SCE shots are high risk and high value making reliability and reproducibility utmost priority. In this regard, major effort is focused on operational performance. A quantitative performance measurement is valuable for tracking and maintaining Cygnus preparedness. In this work, we present a new model for analysis of Cygnus performance. This model uses x-ray dose distribution as the basis for calculation of reliability, record, and reproducibility. It will be applied both to longterm (historical) and short-term (readiness) periods for each of the five SCEs.
Design of the ITER PF Coils

ITER magnets are all designed using superconducting conductors with a high current carrying capability. The Poloidal Field (PF) coils are operated in pulsed mode with maximum operating currents of 48 kA for PF 1 and 6, 55 kA for PF 2,3, and 4 and 52 kA for PF 5. The PF system consists of 6 ring coils, PF1 through PF6, that serve to stabilize the position and control the shape of the plasma in the tokamak. The six PF coils are attached to the outside of the Toroidal Field (TF) coil cases through flexible plates or sliding supports allowing radial displacements. The PF coil positions and sizes have been optimized for the plasma requirements consistent with the constraints imposed by allowing access to the vacuum vessel and by considering pumping ducts to the in-vessel components. The PF coils will all be wound with Niobium-Titanium (NbTi) cable-in-conduit conductors (CICC), and range in diameter from ~8 m to ~24 m. The winding pack consists of stacked double pan cakes, with joints only on the outer radius for access/repair and eddy current/AC loss reasons, while the helium inlets are located at the inner radius. Since the 2001 design option, the PF coil windings and their sub components have been redesigned to satisfy new operational requirements. The final detailed design has been established in 2009 and validated by the design review held the same year. In this paper, the up-to-date design of the PF coils and each sub-component such as winding pack, electrical insulation, joints and terminations, helium inlet, jumpers, and coils' supports are discussed together with their fabrication methods.
Engineering design of a radiative divertor for DIII-D

A new divertor configuration is being developed for the DIII-D tokamak. This divertor will operate in the radiative mode. Experiments and modeling form the basis for the new design. The radiative divertor reduces the heat flux on the divertor plates by dispersing the power with radiation in the divertor region. In addition, the radiative divertor structure will allow density control in plasma shapes required for advanced tokamak operation. The divertor structure allows for operation in either double-null or single-null plasma configurations. Four independently controlled divertor cryopumps will enable pumping at either the inboard (upper and lower) or the outboard (upper and lower) divertor plates. An upgrade to the DIII-D cryogenic system is part of this project. The increased capabilities of the cryogenic system will allow delivery of liquid helium and nitrogen to the three new cryopumps. The radiative divertor design is very flexible, and will allow physics studies of the effects of slot width and length. The slot width is varied by installing graphite tiles of different geometry and can be accomplished in a shut down of less than 3 weeks. The change in slot length requires moving the structure vertically and could to be done in about 6-8 weeks. Slot lengths of 23, 33, and 43 cm have been chosen. Radiative divertor diagnostics are being designed in parallel to provide comprehensive measurements for diagnosing the divertor. The radiative divertor installation is scheduled for late 1996. Engineering experience gained in the DIII-D advanced divertor program form a foundation for the design work on the radiative divertor.
Conceptual modeling of audio-visual content

The explosive growth of applications involving digital audio-visual material is driving the need for more rich content description. The authors present a design process for audio-visual content description. The process involves constructing a conceptual model in which entities, attributes and relationships important for content description are identified and modeled. The procedure provides special handling of different types of spatio-temporal relationships important for audio-visual content modeling. The authors describe the audio-visual content description conceptual modeling methodology in the context of the MPEG-7 description schemes.
New research directions and enhanced potential at the Hawaii Undersea Research Laboratory

The Hawaii Undersea Research Laboratory, NOAA's National Undersea Research Center for Hawaii and the Western Pacific (HURL/NURC-HWP) at the University of Hawaii at Manoa, has been in the process of upgrading its deep submergence system to better address the marine research challenges of the twenty-first century. The recent acquisition of Pisces IV, as a safety backup, will allow a greater range of dive targets to be selected, moving further from Hawaii into the Western Pacific and coral reefs of the Northwest Hawaiian Islands. Substantial upgrades have also taken place on the ROV system, the Pisces V scientific sampling package and the power and propulsion system on the mothership R/V Kaimikai-o-Kanaloa. The number of research submersibles worldwide operating at 2,000 m and below is on the order of 10, including HURL's two Pisces subs. The number of easily transportable systems able to rescue these vehicles is also very small. For this reason, it was the recommendation of the International Submersible Safety Symposium that each of the deep submergence operating groups be able to provide its own rescue capability. HURL has just accomplished this with the addition of Pisces IV.
Accelerated aging of extruded dielectric power cables. II. Life testing of 15 kV XLPE-insulated cables

For pt.I see ibid., p.122-8 (1991). Attempts to successfully use accelerated aging tests to quantify the life of medium voltage power cables in service have been elusive. Preliminary results are described in which 15 kV cross-linked polyethylene (XLPE) cables were subjected to accelerated aging tests under a variety of controlled voltage stress and thermal load cycle conditions, with loss of life being calculated for each set of conditions in terms of the geometric mean time to failure (GMTF). Voltage stress was applied to thin wall (0.76 mm) covered wires in a water bath of controlled nature in the core. Crosslinked polyethylene (XLPE), high molecular weight polyethylene (HMWPE), and ethylene-propylene rubber (EPR) insulations were studied.<<ETX>>
An Effective Strategy for Porting C++ Applications on Cell

In this paper we present a solution for efficient porting of sequential C++ applications on the Cell B.E. processor. We present our step-by-step approach, focusing on its generality, we provide a set of code templates and optimization guidelines to support the porting, and we include a set of equations to estimate the performance gain of the new application. As a case-study, we show the use of our solution on a multimedia content analysis application, named MARVEL. The results of our experiments with MARVEL prove the significant performance increase in favor of the application running on Cell when compared with the reference implementation.
Multi-scale classification based lesion segmentation for dermoscopic images.

This paper presents a robust segmentation method based on multi-scale classification to identify the lesion boundary in dermoscopic images. Our proposed method leverages a collection of classifiers which are trained at various resolutions to categorize each pixel as "lesion" or "surrounding skin". In detection phase, trained classifiers are applied on new images. The classifier outputs are fused at pixel level to build probability maps which represent lesion saliency maps. In the next step, Otsu thresholding is applied to convert the saliency maps to binary masks, which determine the border of the lesions. We compared our proposed method with existing lesion segmentation methods proposed in the literature using two dermoscopy data sets (International Skin Imaging Collaboration and Pedro Hispano Hospital) which demonstrates the superiority of our method with Dice Coefficient of 0.91 and accuracy of 94%.
Electrically-pumped external-cavity surface-emitting laser diodes

Vertical-cavity surface-emitting laser diodes (SELDs) continue to be the topic of much research, and recent results show that they can produce CW powers of above 10 mW without heatsinking. For many applications, a major problem with SELDs is that they only operate in a single transverse mode at low powers. The reason for multiple transverse modes is a combination of the thermal lensing, spatial hole burning, and non-uniform current injection. We demonstrate the use of an external cavity to maintain single transverse mode operation at all currents. More specifically we have reduced the reflectivity of the top mirror from above 99% to 85% and placed the SELD in an external cavity. This results in transverse modes controlled by the external cavity, not by the SELD. The modes of the external cavity can then be controlled by the use of an aperture in the external cavity or by adjusting the cavity length. In order to provide more uniform current spreading, we designed a novel structure (AlGaAs/GaAs) in which the SELD was grown on a p-doped substrate with the p-doped mirror on the bottom and the n-doped mirror on top. We have observed that the current can spread uniformly over a device as large as 100 /spl mu/m in diameter.<<ETX>>
Interactive content-based retrieval of video

We describe a system for content-based retrieval of video that involves a series of query interactions with the user. The proposed approach allows the user, iteratively and selectively, to integrate different feature- and model-based methods of querying in the search process. This allows the user to choose among different retrieved content, features and matching dimensions, and classifiers, as appropriate, given the query objective and interim retrieval results. We investigate several approaches for integrating featureand model-based queries and results in successive query rounds including iterative filtering, score aggregation, and relevance feedback searching. We describe experimental results of applying the interactive content-based retrieval method to an automatically indexed corpus of 11 hours of video.
Cable cleaning solvents: their use and evaluation

1,1,1 trichloroethane has been designated by the US Environmental Protection Agency (EPA) as a substance that may damage the stratospheric ozone layer, and it will be banned from production in the US by December 31, 1995. For these reasons, alternate solvents that are effective as cable cleaners have been evaluated, and continue to be evaluated by cable, solvent and accessory manufacturers. In addition to the earlier criteria used in evaluating alternates to 1,1,1 trichloroethane, this study points out other important performance properties of potential alternates that should be considered. These properties include personal hygiene and safety, environmental waste classification, cleaning effectiveness, evaporation rate and solvent residues, economics, and ease of handling use.
Mine detection by nuclear quadrupole resonance

Nuclear quadrupole resonance (NQR) methods of mine detection rely on the observation of radiofrequency (RF) signals from the /sup 14/N nuclei present in the explosive. The frequencies of these signals lie between 0.5 and 6 MHz; they are characteristic of a given explosive and provide not only a positive identification but also an estimate of quantity or depth. Unlike the better known technique of nuclear magnetic resonance (NMR), no static magnetic field is needed, so that portable probes can be used. Furthermore, signals are only seen in solids or solid-like materials, and because of the highly compound-specific nature of NQR frequencies, there is little, if any interference from other nitrogen-containing materials which may be present in the mine casing or the surrounding terrain. The paper discusses the principles of NQR and experimental methods, and its application to mine detection.
Robust Detection of Stochastic Nuclear Quadrupole Resonance Signals

Nuclear quadrupole resonance (NQR) is a solid-state radio frequency (RF) spectroscopic technique, allowing the detection of compounds containing quadrupolar nuclei, a requirement fulfilled by many high explosives and narcotics. The practical use of NQR is restricted by the inherently low signal-to-noise ratio (SNR) of the observed signals, a problem that is further exacerbated by the presence of strong RF interference (RFI). The current literature focuses on the use of conventional, multiple-pulsed NQR (cNQR) to obtain signals. Here, we investigate an alternative method called stochastic NQR (sNQR), having many advantages over cNQR, one of which is the availability of signal-of-interest free samples. In this paper, we exploit these samples forming a matched subspace-type detector and a detector employing a prewhitening approach, both of which are able to efficiently reduce the influence of RFI. Further, many of the ideas already developed for cNQR, including providing robustness to uncertainties in the assumed complex amplitudes and exploiting the temperature dependencies of the NQR spectral components, are recast for sNQR. The presented detectors are evaluated on both simulated and measured trinitro-toluene (TNT) data.
Real-time video surveillance for traffic monitoring using virtual line analysis

A real-time video surveillance is presented for traffic monitoring of vehicle volume on major highways. Determining traffic volume automatically and in real-time assists drivers to dynamically plan their trips more efficiently. Our traffic monitoring system uses the virtual line graph to facilitate the detection of vehicles, classification of vehicle types, tracking of individual vehicles, and subsequently an accurate count of the number of vehicles. The virtual line analyzer detects vehicles as they cross a virtual boundary. The goal of this traffic monitoring system is to provide a real-time and accurate vehicle counter while taking advantage of stationary Web-cams, fixed highways and lanes, and deterministic vehicle characteristics.
You are what you tweet…pic! gender prediction based on semantic analysis of social media images

We propose a method to extract user attributes from the pictures posted in social media feeds, specifically gender information. While traditional approaches rely on text analysis or exploit visual information only from the user profile picture or colors, we propose to look at the distribution of semantics in the pictures coming from the whole feed of a person to estimate gender. In order to compute such semantic distribution, we trained models from existing visual taxonomies to recognize objects, scenes and activities, and applied them to the images in each user's feed. Experiments conducted on a set of ten thousand twitter users and their collection of half a million images revealed that the gender signal can indeed be extracted from the users image feed (75.6% accuracy). Furthermore, the combination of visual cues resulted almost as strong as textual analysis in predicting gender, while providing complementary information that can be employed to further boost gender prediction accuracy to 88% when combined with textual data. As a byproduct of our investigation, we were also able to extrapolate the semantic categories of posted pictures mostly correlated to males and females.
Fabrication and installation of the DIII-D radiative divertor structures

Phase 1A of the Radiative Divertor Program (RDP) is now installed in the DIII-D tokamak located at General Atomics. This hardware was added to enhance both the Divertor and Advanced Tokamak research elements of the DIII-D program. This installation consists of a divertor baffle enveloping a cryocondensation pump at the upper outer divertor target of DIII-D. The divertor baffle consists of two toroidally continuous Inconel 625 water-cooled rings and a toroidal array of discontinuous radiatively-cooled plates. The water-cooled rings are each comprised of four quadrants, mechanically formed, chem.-milled, and resistance and TIG welded Inconel 625 panels. The supports attaching the panels to the vessel wall are designed to accommodate the differential thermal expansion between the rings and vessel during bake and to react the electromagnetic loads induced during disruptions. They are made from either Inconel 625 or Inconel 718 depending on the stress levels predicted in Finite Element Analysis. Gas seals are designed to limit the leakage from the baffle chamber back to the core plasma to 2,500 l/s and incorporate plasma sprayed alumina to minimize currents flowing through them. The bulk of the water-cooled ring fabrication was performed by a vendor, however, the final machining of penetrations in the conical ring for diagnostic access was performed in-house using a unique machining configuration. This configuration, and the machining of the diagnostic cutouts is described. Graphite tiles were machined from ATJ graphite to form a smooth plasma-facing surface. The installation of all divertor components required only four weeks. This divertor installation included electro-discharge welding studs, accurately locating the supports using a toroidally continuous tooling plate and local fixtures, and mounting the structures. Tooling was used during ex-vessel test assembly to greatly simplify the installation process. This process is reviewed.
Plans for a collaboratively developed distributed control system for the Spallation Neutron Source

The Spallation Neutron Source (SNS) is an accelerator-based pulsed neutron source to be built in Oak Ridge, Tennessee. The facility has five major sections-a "front end" consisting of a 65 kev H ion source followed by a 2.5 MeV RFQ; a 1 GeV linac; a storage ring; a 1 MW spallation neutron target (upgradeable to 2 MW); the conventional facilities to support these machines and a suite of neutron scattering instruments to exploit them. These components will be designed and implemented by five collaborating institutions: Lawrence Berkeley National Laboratory (Front End), Los Alamos National Laboratory (Linac); Brookhaven National Laboratory (Storage Ring); Argonne National Laboratory (Instruments); and Oak Ridge National Laboratory (Neutron Source and Conventional Facilities). It is proposed to implement a fully integrated control system for all aspects of this complex. The system will be developed collaboratively, with some degree of local autonomy for distributed systems, but centralized accountability. Technical integration will be based upon the widely-used EPICS control system toolkit, and a complete set of hardware and software standards. The scope of the integrated control system includes site-wide timing and synchronization, networking and machine protection. This paper discusses the technical and organisational issues of planning a large control system to be developed collaboratively at five different institutions, the approaches being taken to address those issues, as well as some of the particular technical challenges for the SNS control system.