2,505 research outputs found

    Thermal and cryogenic design study for space infrared telescope facility (SIRTF)

    Get PDF
    A study was conducted to determine the ability of an all superfluid helium design to meet the performance requirements of background limited to 200 micrometer, and a two year lifetime for a one meter class free flying infrared observatory. Both a 98 deg and 28.5 deg inclination orbits were examined, and aperture shade designs were developed for both orbits. A unique forebaffle cooling design significantly reduces the sensitivity to aperture heat loads. With certain restrictions on observing modes, the study determined that an all superfluid helium Dewar will meet the temperature and lifetime requirements. A dual cryogen SFHe/SH2 system was also investigated for the 28.5 deg orbit and found to provide a more constant forebaffle temperature but with only a slight improvement in lifetime

    Photovoltaic village power application: Assessment of the near-term market

    Get PDF
    The village power application represents a potential market for photovoltaics. The price of energy for photovoltaic systems was compared to that of utility line extensions and diesel generators. The potential domestic demand was defined in both the government and commercial sectors. The foreign demand and sources of funding for village power systems in the developing countries were also discussed briefly. It was concluded that a near term domestic market of at least 12 MW min and a foreign market of about 10 GW exists

    Photovoltaic remote instrument applications: Assessment of the near-term market

    Get PDF
    A preliminary assessment of the near term market for photovoltaic remote instrument applications is presented. Among the potential users, two market sectors are considered: government and private. However, the majority of the remote systems studied are operated by or for the federal, state, or local governments. Environmental monitoring and surveillance remote instrument systems are discussed. Based on information obtained in this preliminary market survey, a domestic, civilian market of at least 1.3 MW sub pk is forecast for remote instrument systems. This estimate is exclusive of several potentially large scale markets for remote instruments which are identified but for which no hard data is available

    Photovoltaic highway applications: Assessment of the near-term market

    Get PDF
    A preliminary assessment of the near-term market for photovoltaic highway applications is presented. Among the potential users, two market sectors are considered: government and commercial. Within these sectors, two possible application areas, signs and motorist aids, are discussed. Based on judgemental information, obtained by a brief survey of representatives of the two user sectors, the government sector appears more amenable to the introduction of photovoltaic power sources for highway applications in the near-term. However, considerable interest and potential opportunities were also found to exist in the commercial sector. Further studies to quantify the market for highway applications appear warranted

    Photovoltaic refrigeration application: Assessment of the near-term market

    Get PDF
    This foreign and domestic market assessment was performed as part of the Tests and Applications Project being conducted by NASA-LeRC as part of the Department of Energy's (DOE) National Photovoltaic Program. One of the objectives of that program was to stimulate the demand for photovoltaic power systems so that appropriate markets would be developed in concert with the increasing photovoltaic production capacity. The refrigeration application represented a possible market for photovoltaics; hence, a brief survey of potential applications was conducted. Both refrigerators and refrigeration systems were considered in the assessment although the primary emphasis is on refrigerators of 9 cu ft of less. Three user sectors were examined: (1) government, (2) commercial/institutional, and (3) general public

    Photovoltaic water pumping applications: Assessment of the near-term market

    Get PDF
    Water pumping applications represent a potential market for photovoltaics. The price of energy for photovoltaic systems was compared to that of utility line extensions and diesel generators. The potential domestic demand was defined in the government, commercial/institutional and public sectors. The foreign demand and sources of funding for water pumping systems in the developing countries were also discussed briefly. It was concluded that a near term domestic market of at least 240 megawatts and a foreign market of about 6 gigawatts exist

    Dairy foods and osteoporosis: an example of assessing the health-economic impact of food products

    Get PDF
    __Abstract__ Osteoporosis has become a major health concern, carrying a substantial burden in terms of health outcomes and costs. We constructed a model to quantify the potential effect of an additional intake of calcium from dairy foods on the risk of osteoporotic fracture, taking a health economics perspective. Introduction: This study seeks, first, to estimate the impact of an increased dairy consumption on reducing the burden of osteoporosis in terms of health outcomes and costs, and, second, to contribute to a generic methodology for assessing the health-economic outcomes of food products. Methods: We constructed a model that generated the number of hip fractures that potentially can be prevented with dairy foods intakes, and then calculated costs avoided, considering the healthcare costs of hip fractures and the costs of additional dairy foods, as well as the number of disability-adjusted life years (DALYs) lost due to hip fractures associated with low nutritional calcium intake. Separate analyses were done for The Netherlands, France, and Sweden, three countries with different levels of dairy products consumption. Results: The number of hip fractures that may potentially be prevented each year with additional dairy products was highest in France (2,023), followed by Sweden (455) and The Netherlands (132). The yearly number of DALYs lost was 6,263 for France, 1,246 for Sweden, and 374 for The Netherlands. The corresponding total costs that might potentially be avoided are about 129 million, 34 million, and 6 million Euros, in these countries, respectively. Conclusions: This study quantified the potential nutrition economic impact of increased dairy consumption on osteoporotic fractures, building connections between the fields of nutrition and health economics. Future research should further collect longitudinal population data for documenting the net benefits of increasing dairy consumption on bone health and on the related utilization of healthcare resources

    Prototyping of petalets for the Phase-II Upgrade of the silicon strip tracking detector of the ATLAS Experiment

    Full text link
    In the high luminosity era of the Large Hadron Collider, the HL-LHC, the instantaneous luminosity is expected to reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. To cope with the resultant increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The ITk consists of a silicon pixel and a strip detector and exploits the concept of modularity. Prototyping and testing of various strip detector components has been carried out. This paper presents the developments and results obtained with reduced-size structures equivalent to those foreseen to be used in the forward region of the silicon strip detector. Referred to as petalets, these structures are built around a composite sandwich with embedded cooling pipes and electrical tapes for routing the signals and power. Detector modules built using electronic flex boards and silicon strip sensors are glued on both the front and back side surfaces of the carbon structure. Details are given on the assembly, testing and evaluation of several petalets. Measurement results of both mechanical and electrical quantities are shown. Moreover, an outlook is given for improved prototyping plans for large structures.Comment: 22 pages for submission for Journal of Instrumentatio

    Enabling Technologies for Silicon Microstrip Tracking Detectors at the HL-LHC

    Full text link
    While the tracking detectors of the ATLAS and CMS experiments have shown excellent performance in Run 1 of LHC data taking, and are expected to continue to do so during LHC operation at design luminosity, both experiments will have to exchange their tracking systems when the LHC is upgraded to the high-luminosity LHC (HL-LHC) around the year 2024. The new tracking systems need to operate in an environment in which both the hit densities and the radiation damage will be about an order of magnitude higher than today. In addition, the new trackers need to contribute to the first level trigger in order to maintain a high data-taking efficiency for the interesting processes. Novel detector technologies have to be developed to meet these very challenging goals. The German groups active in the upgrades of the ATLAS and CMS tracking systems have formed a collaborative "Project on Enabling Technologies for Silicon Microstrip Tracking Detectors at the HL-LHC" (PETTL), which was supported by the Helmholtz Alliance "Physics at the Terascale" during the years 2013 and 2014. The aim of the project was to share experience and to work together on key areas of mutual interest during the R&D phase of these upgrades. The project concentrated on five areas, namely exchange of experience, radiation hardness of silicon sensors, low mass system design, automated precision assembly procedures, and irradiations. This report summarizes the main achievements

    Patency of endoscopic ultrasound-guided gastroenterostomy in the treatment of malignant gastric outlet obstruction

    Get PDF
    Background and study aims Endoscopic ultrasoundguided gastroenterostomy (EUS-GE) with a lumen-apposing metal stent (LAMS) is a novel, minimally invasive technique in the palliative treatment of malignant gastric outlet obstruction (GOO). Several studies have demonstrated feasibility and safety of EUS-GE, but evidence on long-term durability is limited. The aim of this study was to evaluate patency of EUS-GE in treatment of malignant GOO. Patients and Methods An international multicenter study was performed in seven centers in four European countries. Patients who underwent EUS-GE with a LAMS between March 2015 and March 2019 for palliative treatment of symptomatic malignant GOO were included retrospectively. Our main outcome was recurrent obstruction due to LAMS dysfunction; other outcomes of interest were technical success, clinical success, adverse events (AEs), and survival. Results A total of 45 patients (mean age 69.9 ± 12.3 years and 48.9% male) were included. Median duration of followup was 59 days (interquartile range [IQR] 41–128). Recurrent obstruction occurred in two patients (6.1 %), after 33 and 283 days of follow-up. Technical success was achieved in 39 patients (86.7 %). Clinical success was achieved in 33 patients (73.3 %). AEs occurred in 12 patients (26.7 %), of which five were fatal. Median overall survival was 57 days (IQR 32–114). Conclusions EUS-GE showed a low rate of recurrent obstruction. The relatively high number of fatal AEs underscores the importance of careful implementation of EUSGE in clinical practice
    • …
    corecore