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Sample records for accelerated aging tests

  1. Accelerated aging tests of liners for uranium mill tailings disposal

    Barnes, S.M.; Buelt, J.L.; Hale, V.Q.

    1981-11-01

    This document describes the results of accelerated aging tests to determine the long-term effectiveness of selected impoundment liner materials in a uranium mill tailings environment. The study was sponsored by the US Department of Energy under the Uranium Mill Tailings Remedial Action Project. The study was designed to evaluate the need for, and the performance of, several candidate liners for isolating mill tailings leachate in conformance with proposed Environmental Protection Agency and Nuclear Regulatory Commission requirements. The liners were subjected to conditions known to accelerate the degradation mechanisms of the various liners. Also, a test environment was maintained that modeled the expected conditions at a mill tailings impoundment, including ground subsidence and the weight loading of tailings on the liners. A comparison of installation costs was also performed for the candidate liners. The laboratory testing and cost information prompted the selection of a catalytic airblown asphalt membrane and a sodium bentonite-amended soil for fiscal year 1981 field testing.

  2. Accelerated aging tests of liners for uranium mill tailings disposal

    This document describes the results of accelerated aging tests to determine the long-term effectiveness of selected impoundment liner materials in a uranium mill tailings environment. The study was sponsored by the US Department of Energy under the Uranium Mill Tailings Remedial Action Project. The study was designed to evaluate the need for, and the performance of, several candidate liners for isolating mill tailings leachate in conformance with proposed Environmental Protection Agency and Nuclear Regulatory Commission requirements. The liners were subjected to conditions known to accelerate the degradation mechanisms of the various liners. Also, a test environment was maintained that modeled the expected conditions at a mill tailings impoundment, including ground subsidence and the weight loading of tailings on the liners. A comparison of installation costs was also performed for the candidate liners. The laboratory testing and cost information prompted the selection of a catalytic airblown asphalt membrane and a sodium bentonite-amended soil for fiscal year 1981 field testing

  3. Accelerated aging of IG units : North American test methods

    Both Canadian and American standards have been in place for decades to determine argon gas concentration in insulating glass (IG) units. Efforts are underway to harmonize the IG standards to have acceptable test methods for the durability of IG units and to implement a single certification program for both Canada and the United States. One way to test the durability and integrity of the edge seal on IG units is to subject them to accelerated aging cycles in a controlled environment. This paper summarizes the Canadian, American and the harmonized test methods used in testing the integrity of the seal and the determination of argon gas in IG units. The Canadian standard (CAN/CGSB 12.8) encompasses the following tests: initial seal of units, initial dew point, initial argon concentration, failure analysis (water immersion test), weather cycling, volatile fogging (UV), dew point measurement after weather cycling, high humidity cycling, and final argon concentration. American ASTM E773 and ASTM E774 differ from the Canadian standard in the sequence of testing and the rating of IG units, creating problems for certification of units being shipped across the border. It was noted that adopting a single certification program for Canada and the United States would bring economic benefits to both consumers and manufacturers. 7 refs., 5 figs

  4. Ageing evaluation of low voltage cables and insulators with gamma ray irradiation and thermal accelerated ageing tests

    To optimize lifetime prediction method of cables and to understand cable ageing mechanism, ageing evaluation of low voltage cables and insulators with gamma ray irradiation and thermal accelerated ageing tests were conducted. Insulators had no indication of the ageing after 1000 hours of the accelerated ageing tests. (author)

  5. ACCELERATED AGING TEST IN DETERMINING THE VIGOUR OF SUNFLOWER SEEDS WITH AND WITHOUT PERICARP

    K. R. Ducatti

    2014-09-01

    Full Text Available The standard germination test alone is insufficient to attest the quality of seeds, making necessary correlation’s with vigour tests, to determine more accurately the physiological potential of a seeds lot. The accelerated aging test is an option for determine the vigour and consists in submits seeds to high temperatures and humidity, for different periods of time, has not yet standardized. The objective of this work was to analyze the efficiency of the accelerated aging test in the assessment of the effect of a lot of sunflower seed, by three periods of aging (48, 56 and 72 hours in 42 °C temperature, in seeds with and without pericarp (manually removed and relate the results with electrical conductivity test and germination first count. The experimental design was a completely randomized design and the comparison of averages made using Tukey's test at 5% probability. The results showed that standard germination, electrical conductivity and germination first count, the seeds without pericarp showed better performance. In relation to the accelerated aging, only in the period of 72 hours of aging there was no significant difference between the treatments. In this way, the appropriate period to identify differences in force between the treatments was 72 hours, which showed a positive correlation with the germination first count and electrical conductivity.

  6. Seismic-fragility tests of new and accelerated-aged Class 1E battery cells

    The seismic-fragility response of naturally-aged nuclear station safety-related batteries is of interest for two reasons: (1) to determine actual failure modes and thresholds and (2) to determine the validity of using the electrical capacity of individual cells as an indicator of the potential survivability of a battery given a seismic event. Prior reports in this series discussed the seismic-fragility tests and results for three specific naturally-aged cell types: 12-year old NCX-2250, 10-year old LCU-13, and 10-year old FHC-19. This report focuses on the complementary approach, namely, the seismic-fragility response of accelerated-aged batteries. Of particular interest is the degree to which such approaches accurately reproduce the actual failure modes and thresholds. In these tests the significant aging effects observed, in terms of seismic survivability, were: embrittlement of cell cases, positive bus material and positive plate grids; and excessive sulphation of positive plate active material causing hardening and expansion of positive plates. The IEEE Standard 535 accelerated aging method successfully reproduced seismically significant aging effects in new cells but accelerated grid embrittlement an estimated five years beyond the conditional age of other components

  7. Correlating outdoor exposure with accelerated aging tests for aluminum solar reflectors

    Wette, Johannes; Sutter, Florian; Fernández-García, Aránzazu

    2016-05-01

    Guaranteeing the durability of concentrated solar power (CSP) components is crucial for the success of the technology. The reflectors of the solar field are a key component of CSP plants, requiring reliable methods for service lifetime prediction. So far, no proven correlations exist to relate accelerated aging test results in climate chambers with relevant CSP exposure sites. In this work, correlations have been derived for selected testing conditions that excite the same degradation mechanisms as for outdoor exposure. Those testing conditions have been identified by performing an extensive microscopic comparison of the appearing degradation mechanisms on reference samples that have been weathered outdoors with samples that underwent a high variety of accelerated aging experiments. The herein developed methodology is derived for aluminum reflectors and future work will study its applicability to silvered-glass mirrors.

  8. Evaluation of oxidative behavior of polyolefin geosynthetics utilizing accelerated aging tests based on temperature and pressure

    Li, Mengjia

    Polyolefin geosynthetics are susceptible to oxidation, which eventually leads to the reduction in their engineering properties. In the application of polyolefin geosynthetics, a major issue is an estimate of the materials durability (i.e. service lifetime) under various aging conditions. Antioxidant packages are added to the polyolefin products to extend the induction time, during which antioxidants are gradually depleted and polymer oxidation reactions are prevented. In this PhD study, an improved laboratory accelerating aging method under elevated and high pressure environments was applied to evaluate the combined effect of temperature and pressure on the depletion of the antioxidants and the oxidation of polymers. Four types of commercial polyolefn geosynthetic materials selected for aging tests included HDPE geogrid, polypropylene woven and nonwoven geotextiles. A total of 33 different temperature/pressure aging conditions were used, with the incubation duration up to 24 months. The applied oven temperature ranged from 35°C to 105°C and the partial oxygen pressure ranged from 0.005 MPa to 6.3 MPa. Using the Oxidative Induction Time (OIT) test, the antioxidant depletion, which is correlated to the decrease of the OIT value, was found to follow apparent first-order decay. The OIT data also showed that, the antioxidant depletion rate increased with temperature according to the Arrhenius equation, while under constant temperatures, the rate increased exponentially with the partial pressure of oxygen. A modified Arrhenius model was developed to fit the antioxidant depletion rate as a function of temperature and pressure and to predict the antioxidant lifetime under various field conditions. This study has developed new temperature/pressure incubation aging test method with lifetime prediction models. Using this new technique, the antioxidant lifetime prediction results are close to regular temperature aging data while the aging duration can be reduced considerably

  9. Accelerated aging tests of radiation damaged lasers and photodiodes for the CMS tracker optical links

    Gill, K; Batten, J; Cervelli, G; Grabit, R; Jensen, F; Troska, Jan K; Vasey, F

    1999-01-01

    The combined effects of radiation damage and accelerated ageing in COTS lasers and p-i-n photodiodes are presented. Large numbers of these devices are employed in future High Energy Physics experiments and it is vital that these devices are confirmed to be sufficiently robust in terms of both radiation resistance and reliability. Forty 1310 nm InGaAsP edge-emitting lasers (20 irradiated) and 30 InGaAs p- i-n photodiodes (19 irradiated) were aged for 4000 hours at 80 degrees C with periodic measurements made of laser threshold and efficiency, in addition to p-i-n leakage current and photocurrent. There were no sudden failures and there was very little wearout- related degradation in either unirradiated or irradiated sample groups. The results suggest that the tested devices have a sufficiently long lifetime to operate for at least 10 years inside the Compact Muon Solenoid experiment despite being exposed to a harsh radiation environment. (13 refs).

  10. Imbibitions, energy test and accelerated ageing in primed and non-primed seeds of Peltophorum dubium

    LILei-hong; ZHANGWan-li; ZUYuan-gang; SONIAPerez

    2005-01-01

    Peltophorum dubium seeds were set to imbibe with four treatments, soaked with solution Captan 0.2% under 10and 27℃,PEG 6000 -1.0 MPa under 10 and 27℃. For each treatment there were four replicates with 40 seeds incubated in 9-cm Petri dishes with double filter paper moistened with testing solution. The imbibition curves showed that the final weight increase were from 70% to 150% in the treatments when imbibition entered a lag phase. Seeds were tested for effects on germination of five treatments: control group (nonprimed), primed with PEG6000 -1.0 MPa at 10 and 27℃, primed with Captan 0.2% at 10 and 27℃. For each treatment, there were three sub-treatments: seeds were soaked in distilled water for 12, 24 and 36h before the energy test. Germination percentages of nonprimed seeds and primed in PEG 27℃ soaked in distilled water during 12 h were the highest, reaching 100%. The lowest germination percentage occurred primed seeds with PEG6000 27℃ and soaked in distilled water during 36 h, which was only 52%. Germination mean time of primed seeds in PEG at 10℃, soaked 24 h was 1.08 days, mean time of primed seeds in PEG at 27℃ soaked 12 h was 2.42 days. Accelerated ageing results showed low or no germination after ageing 72 h. Control group had a higher germination percentage and seeds were more resistant to deterioration than those in primed groups, both in Petri dish (27℃) and vermiculate (room temperature).

  11. Methodology for designing accelerated aging tests for predicting life of photovoltaic arrays

    Gaines, G. B.; Thomas, R. E.; Derringer, G. C.; Kistler, C. W.; Bigg, D. M.; Carmichael, D. C.

    1977-01-01

    A methodology for designing aging tests in which life prediction was paramount was developed. The methodology builds upon experience with regard to aging behavior in those material classes which are expected to be utilized as encapsulant elements, viz., glasses and polymers, and upon experience with the design of aging tests. The experiences were reviewed, and results are discussed in detail.

  12. Allowance for insulation aging in the new concept of accelerated life tests of high-voltage power transformers

    This paper reports that the existing system of type and acceptance tests of high-voltage transformer insulation does not take into account insulation ageing, which is particularly objectionable with respect to equip-met with reduced insulation levels. Suggested in the paper is a new concept of accelerated life tests based on integrated simulation of basic operating loads, both periodic (surge) and long-term ones; by making a long-term accelerated test simulating the working conditions, with exposure of test object and/or its insulation to periodic operating surges (overvoltages and overcurrents). This test replaces a group of conventional individual acceptance tests and provides more ample and more precise information on performance and dependability of the equipment. The test procedure was checked in test of a small lot of 1600 kVA 35 kV power transformers

  13. Development of an accelerated pavement test reproducing the effect of natural ageing on skid resistance

    Kane, M.; D. Zhao; Chailleux, E.; Delarrard, F.; Do, M. T.

    2013-01-01

    This study deals with the development of a new test method simulating the effect of ageing on skid resistance. This test is applied to bituminous mixes in this study, but can also be applied to concrete. This test relies on two machines, the Wehner–Schulze machine, to measure the friction, and the Weatherometer sunset machine, to simulate weather effects (rain, wind, sunlight, etc.). The relevance of this test is evaluated from comparisons between changes in friction and a chemical func...

  14. Ethylene propylene cable degradation during LOCA research tests: tensile properties at the completion of accelerated aging

    Six ethylene-propylene rubber (EPR) insulation materials were aged at elevated temperature and radiation stress exposures common in cable LOCA qualification tests. Material samples were subjected to various simultaneous and sequential aging simulations in preparation for accident environmental exposures. Tensile properties subsequent to the aging exposure sequences are reported. The tensile properties of some, but not all, specimens were sensitive to the order of radiation and elevated temperature stress exposure. Other specimens showed more severe degradation when simultaneously exposed to radiation and elevated temperature as opposed to the sequential exposure to the same stresses. Results illustrate the difficulty in defining a single test procedure for nuclear safety-related qualification of EPR elastomers. A common worst-case sequential aging sequence could not be identified

  15. Metodologia para o teste de envelhecimento acelerado em sementes de ervilha Accelerated aging test on pea seeds

    Warley Marcos Nascimento

    2007-06-01

    ível identificar os lotes de melhor qualidade.Pea production in Brazil uses seeds produced in the country. The objective of this study was to examine the efficiency of the accelerated aging test for vigor evaluation of pea seeds. Five seed lots of cultivar Axé (wrinkled seeds and five seed lots of cultivar Mikado (smooth seeds were used. The initial quality of each seed lot was evaluated by germination test, first counting, and seedling emergence in the field. Seed moisture content was also assessed. The accelerated aging test was set at 41ºC for periods of 24; 48; and 72 hours, with and without saturated NaCl solution. The experiment was carried out in a completely randomized design. The accelerated aging test was efficient for vigor evaluation of pea seeds, and the period of 48 hours at 41ºC, using saturated NaCl solution was the most adequate procedure to indicate vigor levels of pea seeds. However, the seed germination after this period was very low when compared to 24 hour-period (80% for both cultivars, even in higher vigor seed lots (35% for Axé and 38% for Mikado. In the saturated NaCl solution, the period of 48 hours at 41ºC was the most adequate for separate seeds through vigor levels. In these conditions, seed lots of highest vigor showed germination of 68% and 79% for Axé and Mikado, respectively. Results of the germination test, first counting, and seedling emergence were not effective in discriminating physiological seed quality when used individually. Nevertheless, when results from these tests were used all together, it was possible to identify the best seed lots.

  16. IGBT accelerated aging data set.

    National Aeronautics and Space Administration — Preliminary data from thermal overstress accelerated aging using the aging and characterization system. The data set contains aging data from 6 devices, one device...

  17. Accelerated cyclic corrosion tests

    Prošek T.

    2016-01-01

    Accelerated corrosion testing is indispensable for material selection, quality control and both initial and residual life time prediction for bare and painted metallic, polymeric, adhesive and other materials in atmospheric exposure conditions. The best known Neutral Salt Spray (NSS) test provides unrealistic conditions and poor correlation to exposures in atmosphere. Modern cyclic accelerated corrosion tests include intermittent salt spray, wet and dry phases and eventually other technical p...

  18. Quick Preparation of Moisture-Saturated Carbon Fiber-Reinforced Plastics and Their Accelerated Ageing Tests Using Heat and Moisture

    Masao Kunioka

    2016-06-01

    Full Text Available A quick method involving the control of heat and water vapor pressure for preparing moisture-saturated carbon fiber-reinforced plastics (CFRP, 8 unidirectional prepreg layers, 1.5 mm thickness, epoxy resin has been developed. The moisture-saturated CFRP sample was obtained at 120 °C and 0.2 MPa water vapor in 72 h by this method using a sterilizer (autoclave. The bending strength and viscoelastic properties measured by a dynamic mechanical analysis (DMA remained unchanged during repetitive saturation and drying steps. No degradation and molecular structural change occurred. Furthermore an accelerated ageing test with two ageing factors, i.e., heat and moisture was developed and performed at 140–160 °C and 0.36–0.62 MPa water vapor pressure by using a sealed pressure-proof stainless steel vessel (autoclave. The bending strength of the sample decreased from 1107 to 319 MPa at 160 °C and 0.63 MPa water vapor pressure in 9 days. Degraded samples were analyzed by DMA. The degree of degradation for samples was analyzed by DMA. CFRP and degraded CFRP samples were analyzed by using a surface and interfacial cutting analysis system (SAICAS and an electron probe micro-analyzer (EPMA equipped in a scanning electron microscope.

  19. CESR Test Accelerator

    Rubin, David L

    2013-01-01

    The Cornell Electron Storage Ring (CESR) was reconfigured in 2008 as a test accelerator to investigate the physics of ultra-low emittance damping rings. During the approximately 40 days/year available for dedicated operation as a test accelerator, specialized instrumentation is used to measure growth and mitigation of the electron cloud, emittance growth due to electron cloud, intra-beam scattering, and ions, and single and multi-bunch instabilities generated by collective effects. The flexibility of the CESR guide field optics and the integration of accelerator modeling codes with the control system have made possible an extraordinary range of experiments. Findings at CesrTA with respect to electron cloud effects, emittance tuning techniques, and beam instrumentation for measuring electron cloud, beam sizes, and beam positions are the basis for much of the design of the ILC damping rings as documented in the ILC-Technical Design Report. The program has allowed the Cornell group to cultivate the kind of talen...

  20. Testing Gravity on Accelerators

    Kalaydzhyan, Tigran

    2016-01-01

    Weak equivalence principle (WEP) is one of the cornerstones of the modern theories of gravity, stating that the trajectory of a freely falling test body is independent of its internal structure and composition. Even though WEP is known to be valid for the normal matter with a high precision, it has never been experimentally confirmed for relativistic matter and antimatter. We make an attempt to constrain possible deviations from WEP utilizing the modern accelerator technologies. We analyze the (absence of) vacuum Cherenkov radiation, photon decay, anomalous synchrotron losses and the Compton spectra to put limits on the isotropic Lorentz violation and further convert them to the constraints on the difference between the gravitational and inertial masses of the relativistic electrons/positrons. Our main result is the 0.1% limit on the mentioned difference.

  1. Envelhecimento acelerado como teste de vigor para sementes de milho e soja Accelerated aging as test of vigor for corn and soybean seeds

    Alek Sandro Dutra

    2004-06-01

    control program and the accelerated aging test an important procedure for that. This work was carried out in order to search for specific methodologies of evaluation of seed vigor, in laboratory, based on the accelerated aging test. The research was conducted using six seed lots of corn and soybean species, with commercially accepted quality patterns (germination. The prior established conditions for aging were 42ºC/96h and 45ºC/72h for corn and 41ºC/48 and 72h and 42ºC/48 and 72h for soybean. For each combination of temperature and aging periods, the seeds were placed into plastic boxes (gerbox, with 40mL of distilled water, distributed on the screen, using single layer and based on the seed weight. For the aging, two chamber types, BOD and water jacketed were used. The moisture content and germination of seed lots, after aging, were determined. The water uptake considering the combinations of temperature/exposure period, the two chamber types and the two procedures of determining seed moisture content was higher when the seeds were conditioned in a single layer compared to weight (constant mass. For the corn, the combination of 45ºC/72h with the conditioning of the seeds in only layer was the most efficient method for the separation of the lots with relationship to the vigor. For soybean, the combination 42ºC/48h was more efficient in the separation of the lots, not having interference of the method of conditioning of the seeds, in the screen. Considering the results it can be concluded that the single layer distribution should be used for corn and soybean and the BOD chambers should also be used for accelerated aging test for both species.

  2. Teste de envelhecimento precoce para sementes de azevém, aveia preta e milheto Accelerated aging test for ryegrass black oat grass and pearl millet seeds

    Danton Camacho Garcia

    1999-06-01

    Full Text Available A viabilidade da aplicação e da padronização do teste de envelhecimento precoce em sementes de azevém, aveia preta e milheto foi verificada em três lotes, para cada espécie, com valores iniciais de germinação semelhantes. As sementes de cada lote foram submetidas ao teste por períodos de 24, 48, 72, 96 e 120 horas, à temperatura de 41°C e 100% de umidade relativa do ar. Em aveia preta, o período de 24 horas estratifica lotes de sementes pelo vigor. Para milheto e azevém, o período de envelhecimento para estratificar lotes de sementes pelo vigor pode ser de 24 a 48 horas. Períodos de 72 a 120 horas são muito drásticos para as três espécies e impedem a estratificação de lotes de sementes pelo vigor.Accelerated aging test standardization for seeds of ryegrass, black oat grass and pearl millet was cheked in three lots, of each specie, with similar initial values of germination. The seeds of each lot were submited to periods of 24, 48, 96 and 120 hours of temperature of 41°C and air relative humidity of 100%. In black oat grass the 24h period stratifies seed vigor among lots. However, for pearl millet and ryegrass the period can be of 24 to 48h. Periods of 72 to 120 hours are very severe to the three species and prevent the seed vigor lots stratification.

  3. Accelerated Aging in Electrolytic Capacitors for Prognostics

    Celaya, Jose R.; Kulkarni, Chetan; Saha, Sankalita; Biswas, Gautam; Goebel, Kai Frank

    2012-01-01

    The focus of this work is the analysis of different degradation phenomena based on thermal overstress and electrical overstress accelerated aging systems and the use of accelerated aging techniques for prognostics algorithm development. Results on thermal overstress and electrical overstress experiments are presented. In addition, preliminary results toward the development of physics-based degradation models are presented focusing on the electrolyte evaporation failure mechanism. An empirical degradation model based on percentage capacitance loss under electrical overstress is presented and used in: (i) a Bayesian-based implementation of model-based prognostics using a discrete Kalman filter for health state estimation, and (ii) a dynamic system representation of the degradation model for forecasting and remaining useful life (RUL) estimation. A leave-one-out validation methodology is used to assess the validity of the methodology under the small sample size constrain. The results observed on the RUL estimation are consistent through the validation tests comparing relative accuracy and prediction error. It has been observed that the inaccuracy of the model to represent the change in degradation behavior observed at the end of the test data is consistent throughout the validation tests, indicating the need of a more detailed degradation model or the use of an algorithm that could estimate model parameters on-line. Based on the observed degradation process under different stress intensity with rest periods, the need for more sophisticated degradation models is further supported. The current degradation model does not represent the capacitance recovery over rest periods following an accelerated aging stress period.

  4. The Brookhaven Accelerator Test Facility

    The Accelerator Test Facility (ATF), presently under construction at Brookhaven National laboratory, is described. It consists of a 50-MeV electron beam synchronizable to a high-peak power CO2 laser. The interaction of electrons with the laser field will be probed, with some emphasis on exploring laser-based acceleration techniques. 5 refs., 2 figs

  5. 飞艇蒙皮材料加速老化性能试验研究%Research on Accelerated Aging Test of Airship Envelop Material

    张金奎; 刘涛; 鲁国富

    2014-01-01

    目的:研究某飞艇蒙皮材料加速老化性能,以及不同环境因素对飞艇蒙皮材料老化的影响。方法根据某飞艇的使用环境,对 URETEK-3216LV 和 HD-150两种飞艇蒙皮材料进行了实验室加速老化组合试验。结果得到了不同环境条件下两种飞艇蒙皮材料加速老化后断裂强力退化规律。结论 URETEK-3216LV 材料对高湿环境最为敏感,而 HD-150材料对高温环境最为敏感。 URETEK-3216LV 材料耐候性能比 HD-150材料耐候性强。%Objective To study the aging property of envelop material for a certain type of airship and the effect of dif-ferent environmental factors on the airship envelop material. Methods Based on the operation environment of the airship, laboratory accelerated aging combination test was carried out for the two airship envelop materials URETEK-3216LV and HD-150. Results The deterioration law of breaking force of the two airship envelop materials after accelerated aging in dif-ferent environmental conditions was obtained. Conclusion The test results showed that high-humidity environment had the greatest influence on the ageing performance of URETEK-3216LV, while high-temperature environment had the greatest in-fluence on the ageing performance of HD-150. The weatherability of URETEK-3216LV was better than that of HD-150.

  6. Research on Accelerated Aging Test of Airship Envelop Material%飞艇蒙皮材料加速老化性能试验研究

    张金奎; 刘涛; 鲁国富

    2014-01-01

    Objective To study the aging property of envelop material for a certain type of airship and the effect of dif-ferent environmental factors on the airship envelop material. Methods Based on the operation environment of the airship, laboratory accelerated aging combination test was carried out for the two airship envelop materials URETEK-3216LV and HD-150. Results The deterioration law of breaking force of the two airship envelop materials after accelerated aging in dif-ferent environmental conditions was obtained. Conclusion The test results showed that high-humidity environment had the greatest influence on the ageing performance of URETEK-3216LV, while high-temperature environment had the greatest in-fluence on the ageing performance of HD-150. The weatherability of URETEK-3216LV was better than that of HD-150.%目的:研究某飞艇蒙皮材料加速老化性能,以及不同环境因素对飞艇蒙皮材料老化的影响。方法根据某飞艇的使用环境,对 URETEK-3216LV 和 HD-150两种飞艇蒙皮材料进行了实验室加速老化组合试验。结果得到了不同环境条件下两种飞艇蒙皮材料加速老化后断裂强力退化规律。结论 URETEK-3216LV 材料对高湿环境最为敏感,而 HD-150材料对高温环境最为敏感。 URETEK-3216LV 材料耐候性能比 HD-150材料耐候性强。

  7. Environmental aging in polycrystalline-Si photovoltaic modules: comparison of chamber-based accelerated degradation studies with field-test data

    Lai, T.; Biggie, R.; Brooks, A.; Potter, B. G.; Simmons-Potter, K.

    2015-09-01

    Lifecycle degradation testing of photovoltaic (PV) modules in accelerated-degradation chambers can enable the prediction both of PV performance lifetimes and of return-on-investment for installations of PV systems. With degradation results strongly dependent on chamber test parameters, the validity of such studies relative to fielded, installed PV systems must be determined. In the present work, accelerated aging of a 250 W polycrystalline silicon module is compared to real-time performance degradation in a similar polycrystalline-silicon, fielded, PV technology that has been operating since October 2013. Investigation of environmental aging effects are performed in a full-scale, industrial-standard environmental chamber equipped with single-sun irradiance capability providing illumination uniformity of 98% over a 2 x 1.6 m area. Time-dependent, photovoltaic performance (J-V) is evaluated over a recurring, compressed night-day cycle providing representative local daily solar insolation for the southwestern United States, followed by dark (night) cycling. This cycle is synchronized with thermal and humidity environmental variations that are designed to mimic, as closely as possible, test-yard conditions specific to a 12 month weather profile for a fielded system in Tucson, AZ. Results confirm the impact of environmental conditions on the module long-term performance. While the effects of temperature de-rating can be clearly seen in the data, removal of these effects enables the clear interpretation of module efficiency degradation with time and environmental exposure. With the temperature-dependent effect removed, the normalized efficiency is computed and compared to performance results from another panel of similar technology that has previously experienced identical climate changes in the test yard. Analysis of relative PV module efficiency degradation for the chamber-tested system shows good comparison to the field-tested system with ~2.5% degradation following

  8. U.S.-French Cooperative Research Program: U.S. test results for cable insulation and jacket materials at the completion of accelerated aging

    Eight different U.S. insulation and jacket products have been accelerated aged at Sandia. The experimental variables included: (1) sequential versus simultaneous accelerated aging exposures; (2) the order of the sequential exposures; and (3) ambient versus 700C irradiation temperatures during sequential aging exposures. We observed that the irradiation temperature (700C or ambient) was secondary in importance to the choice of sequence for thermal and radiation aging. For most materials studied (except TEFZEL) the irradiation then thermal aging sequence was as severe or more severe than the thermal then irradiation aging sequence

  9. Advanced Superconducting Test Accelerator (ASTA)

    Federal Laboratory Consortium — The Advanced Superconducting Test Accelerator (ASTA) facility will be based on upgrades to the existing NML pulsed SRF facility. ASTA is envisioned to contain 3 to...

  10. Accelerated aging tests on ENEA-ASE solar coating for receiver tube suitable to operate up to 550 °C

    Antonaia, A.; D'Angelo, A.; Esposito, S.; Addonizio, M. L.; Castaldo, A.; Ferrara, M.; Guglielmo, A.; Maccari, A.

    2016-05-01

    A patented solar coating for evacuated receiver, based on innovative graded WN-AlN cermet layer, has been optically designed and optimized to operate at high temperature with high performance and high thermal stability. This solar coating, being designed to operate in solar field with molten salt as heat transfer fluid, has to be thermally stable up to the maximum temperature of 550 °C. With the aim of determining degradation behaviour and lifetime prediction of the solar coating, we chose to monitor the variation of the solar absorptance αs after each thermal annealing cycle carried out at accelerated temperatures under vacuum. This prediction method was coupled with a preliminary Differential Thermal Analysis (DTA) in order to give evidence for any chemical-physical coating modification in the temperature range of interest before performing accelerated aging tests. In the accelerated aging tests we assumed that the temperature dependence of the degradation processes could be described by Arrhenius behaviour and we hypothesized that a linear correlation occurs between optical parameter variation rate (specifically, Δαs/Δt) and degradation process rate. Starting from Δαs/Δt values evaluated at 650 and 690 °C, Arrhenius plot gave an activation energy of 325 kJ mol-1 for the degradation phenomenon, where the prediction on the coating degradation gave a solar absorptance decrease of only 1.65 % after 25 years at 550 °C. This very low αs decrease gave evidence for an excellent stability of our solar coating, also when employed at the maximum temperature (550 °C) of a solar field operating with molten salt as heat transfer fluid.

  11. Accelerated Aging in Electrolytic Capacitors for Prognostics

    National Aeronautics and Space Administration — The focus of this work is the analysis of different degradation phenomena based on thermal overstress and electrical overstress accelerated aging systems and the...

  12. Accelerated Testing Validation

    Mukundan, Rangachary; James, Greg; Davey, John; Langlois, David; Torraco, Dennis; Yoon, Wonseok; Weber, Adam Z; Borup, Rodney L.

    2011-07-01

    The DOE Fuel Cell technical team recommended ASTs were performed on 2 different MEAs (designated P5 and HD6) from Ballard Power Systems. These MEAs were also incorporated into stacks and operated in fuel cell bus modules that were either operated in the field (three P5 buses) in Hamburg, or on an Orange county transit authority drive cycle in the laboratory (HD6 bus module). Qualitative agreement was found in the degradation mechanisms and rates observed in the AST and in the field. The HD6 based MEAs exhibited lower voltage degradation rates (due to catalyst corrosion) and slower membrane degradation rates in the field as reflected by their superior performance in the high potential hold and open-circuit potential AST tests. The quantitative correlation of the degradation rates will have to take into account the various stressors in the field including temperature, relative humidity, start/stops and voltage cycles.

  13. Test accelerator for linear collider

    KEK has proposed to build Test Accelerator Facility (TAF) capable of producing a 2.5 GeV electron beam for the purpose of stimulating R ampersand D for linear collider in TeV region. The TAF consists of a 1.5 GeV S-band linear accelerator, 1.5 GeV damping ring and 1.0 GeV X-band linear accelerator. The TAF project will be carried forward in three phases. Through Phase-I and Phase-II, the S-band and X-band linacs will be constructed, and in Phase-III, the damping ring will be completed. The construction of TAF Phase-I has started, and the 0.2 GeV S-band injector linac has been almost completed. The Phase-I linac is composed of a 240 keV electron gun, subharmonic bunchers, prebunchers and traveling buncher followed by high-gradient accelerating structures. The SLAC 5045 klystrons are driven at 450 kV in order to obtain the rf-power of 100 MW in a 1 μs pulse duration. The rf-power from a pair of klystrons are combined into an accelerating structure. The accelerating gradient up to 100 MeV/m will be obtained in a 0.6 m long structure. 5 refs., 3 figs., 2 tabs

  14. Teste de frio e envelhecimento acelerado na avaliação de vigor de sementes de feijão-frade Evaluation of the cowpea seeds vigour through of the coldtest and accelerated aging test

    Josiane Marlle Guiscem

    2010-12-01

    Full Text Available Este trabalho teve como objetivo avaliar o vigor de sementes de feijão-caupi ou feijão-frade por meio dos testes de frio e de envelhecimento acelerado. Utilizou-se as seguintes cultivares de feijão-frade: BRS Guariba, BR 17 Gurguéia, BRS Marataoã, Quarentão e Vinagre. O experimento foi conduzido na Universidade Estadual do Maranhão onde se utilizou para o teste de envelhecimento acelerado as temperaturas e tempo de exposição: 41ºC, 42ºC 43ºC e 45ºC durante 48 h e 42ºC durante 72 h e para o teste de frio: 10ºC, 13ºC e 15ºC com 3, 4 e 5 dias de exposição. Os resultados revelaram que o teste de envelhecimento acelerado com 43ºC/48 h e para o de frio 10º /3 dias foram os mais adequados e que os testes de envelhecimento 42ºC /48 h e de frio 10ºC/3dias se correlacionaram entre si coeficiente de correlação de 0,97%. Pelos resultados conclui-se que os testes estudados apresentaram sensibilidade para identificar diferenças no vigor de sementes de feijão-frade.Aiming to evaluate the efficiency of different methods of accelerated aging and cold test to determine the physiological quality of seed of five cultivars of cowpea: BRS Guariba, BR 17 Gurguéia, BRS Marataoã, Quarentão e Vinagre. The experiment was conducted at the laboratory of University State of Maranhão - UEMA. In the accelera-ted aging test were used the following temperature and time of exposure: 41ºC, 42°C , 43°C and 45°C for 48 hours and 42 ° C for 72 hours. In cold test were used 10ºC, 13°C and 15ºC for 3, 4 and 5 days of exposure. Tests showed that the accelerated aging test of the combination of 43ºC/48 hours and for cold test the combination 15ºC/ 5 days were the most appropriate for the evaluation of the potential of physiological cultivars of cowpea seed. The accelerated aging tests 42°C/48 hours and of cold test 15ºC/3 days were those that had greater consistency in the separation of lots of cultivars of seed cowpea because of correlation

  15. Improving motor reliability in nuclear power plants: Volume 2, Functional indicator tests on a small electric motor subjected to accelerated aging

    A ten horsepower electric motor was artificially aged by plug reverse cycling for test purposes. The motor was manufactured in 1967 and was in service at a commercial nuclear power plant for twelve years. Various tests were performed on the motor throughout the aging process. The motor failed after 3.79 million reversals (3 seconds per reversal) over seven months of testing. Each test parameter was trended to assess its suitability in monitoring aging and service wear degradation in motors. Results and conclusions are discussed relative to the applicability of the tests performed to nuclear power plant motor maintenance programs. 15 refs., 28 figs., 1 tab

  16. The Brookhaven National Laboratory Accelerator Test Facility

    The Brookhaven National Laboratory Accelerator Test Facility comprises a 50 MeV traveling wave electron linear accelerator utilizing a high gradient, photo-excited, raidofrequency electron gun as an injector and an experimental area for study of new acceleration methods or advanced radiation sources using free electron lasers. Early operation of the linear accelerator system including calculated and measured beam parameters are presented together with the experimental program for accelerator physics and free electron laser studies

  17. Accelerated aging and seedling field emergence in soybean

    Torres Reynaldo Melo; Vieira Roberval Daiton; Panobianco Maristela

    2004-01-01

    Information regarding the relationship between laboratory seed vigor testing and seedling field emergence is very important to estimate seed performance after sowing and help producers adopt the best procedures to improve stand establishment. The objective of the present study was to relate accelerated aging (AA) test results to soybean [Glycine max (L.) Merrill] seedling field emergence results based on data obtained over three agricultural years. The following evaluations were made: seed wa...

  18. Accelerated tests of coil coatings

    Rosales, B. M.

    2003-12-01

    Full Text Available Accelerated laboratory tests on 12 materials in study in the Subgroup 6 of the PATINA Network (CYTED, are discussed for different exposition periods in salt spray, SO2 and Prohesion chambers. International standards used to evaluate failures caused by the different aggressive agents of these laboratory tests are the same as those applied for outdoor expositions. The results exposed contribute to a better understanding of the mechanisms occurred in the diverse natural environments, being mentioned the main analogies and differences respect to factors affecting natural tests. They also allowed to evidence the advantages and limitations in the application of these tests during several days, as compared to the years required to attain similar failure magnitudes through outdoor tests.

    En este trabajo se discuten los ensayos de laboratorio acelerados, realizados sobre 12 materiales de estudio en el Subgrupo 6 de la Red PATINA (CYTED, a diferentes periodos de exposición en cámaras de niebla salina, SO2 y Prohesion. Se utilizaron las normas internacionales para evaluar los fallos causados por los diferentes agentes agresivos de estos ensayos de laboratorio, las cuales se aplican también para los ensayos de exposición a la intemperie. Los resultados expuestos contribuyen a una mejor comprensión de los mecanismos ocurridos en los diversos ambientes naturales, mencionándose las principales analogías y diferencias respecto de los factores que afectan los ensayos naturales. También permitieron evidenciar las ventajas y limitaciones en la aplicación de estos ensayos durante varios días, en comparación con los años requeridos para alcanzar magnitudes de fallos similares por medio de ensayos a intemperie.

  19. Accelerators for Fusion Materials Testing

    Knaster, Juan; Okumura, Yoshikazu

    Fusion materials research is a worldwide endeavor as old as the parallel one working toward the long term stable confinement of ignited plasma. In a fusion reactor, the preservation of the required minimum thermomechanical properties of the in-vessel components exposed to the severe irradiation and heat flux conditions is an indispensable factor for safe operation; it is also an essential goal for the economic viability of fusion. Energy from fusion power will be extracted from the 14 MeV neutron freed as a product of the deuterium-tritium fusion reactions; thus, this kinetic energy must be absorbed and efficiently evacuated and electricity eventually generated by the conventional methods of a thermal power plant. Worldwide technological efforts to understand the degradation of materials exposed to 14 MeV neutron fluxes >1018 m-2s-1, as expected in future fusion power plants, have been intense over the last four decades. Existing neutron sources can reach suitable dpa (“displacement-per-atom”, the figure of merit to assess materials degradation from being exposed to neutron irradiation), but the differences in the neutron spectrum of fission reactors and spallation sources do not allow one to unravel the physics and to anticipate the degradation of materials exposed to fusion neutrons. Fusion irradiation conditions can be achieved through Li (d, xn) nuclear reactions with suitable deuteron beam current and energy, and an adequate flowing lithium screen. This idea triggered in the late 1970s at Los Alamos National Laboratory (LANL) a campaign working toward the feasibility of continuous wave (CW) high current linacs framed by the Fusion Materials Irradiation Test (FMIT) project. These efforts continued with the Low Energy Demonstrating Accelerator (LEDA) (a validating prototype of the canceled Accelerator Production of Tritium (APT) project), which was proposed in 2002 to the fusion community as a 6.7MeV, 100mA CW beam injector for a Li (d, xn) source to bridge

  20. An Accelerated Stress Test Method for Electrostatically Driven MEMS Devices

    Ruan, Jinyu Jason; Monnereau, Nicolas; Trémouilles, David; Mauran, Nicolas; Coccetti, Fabio; Nolhier, Nicolas; Plana, Robert

    2012-01-01

    This paper addresses an innovative solution to develop a circuit to perform accelerated stress tests of capacitive microelectromechanical-system (MEMS) switches and shows the use of instruments and equipment to monitor physical aging phenomena. A dedicated test circuit was designed and fabricated in order to meet the need for accelerated techniques for those structures. It integrated an in-house miniaturized circuit connected to additional test equipment (e.g., oscilloscopes and capacitance m...

  1. US Particle Accelerators at Age 50.

    Wilson, R. R.

    1981-01-01

    Reviews the development of accelerators over the past 50 years. Topics include: types of accelerators, including cyclotrons; sociology of accelerators (motivation, financing, construction, and use); impact of war; national laboratories; funding; applications; future projects; foreign projects; and international collaborations. (JN)

  2. Premature and accelerated ageing: HIV or HAART?

    Reuben Luke Smith

    2013-01-01

    Full Text Available Highly Active Anti-Retroviral Therapy (HAART has significantly increased life expectancy of the HIV-positive population. Nevertheless, the average lifespan of HIV patients remains shorter compared to uninfected individuals. Immunosenescence, a current explanation for this difference invokes heavily on viral stimulus despite HAART efficiency in viral suppression. We propose here that the premature and accelerated ageing of HIV patients can also be caused by adverse effects of antiretroviral drugs, specifically those that affect the mitochondria. The Nucleoside Reverse Transcriptase Inhibitor (NRTI antiretroviral drug class for instance, is known to cause depletion of mitochondrial DNA via inhibition of the mitochondrial specific DNA polymerase-ƴ. Besides NRTIs, other antiretroviral drug classes such as Protease Inhibitors also cause severe mitochondrial damage by increasing oxidative stress and diminishing mitochondrial function. We also discuss important areas for future research and argue in favour of the use of C. elegans as a novel model system for studying these effects.

  3. Dynamic mechanical and molecular weight measurements on polymer bonded explosives from thermally accelerated aging tests. III. Kraton block copolymer binder and plasticizers

    The dynamic mechanical properties and molecular weight distribution of two experimental polymer bonded explosives, X-0287 and X-0298, maintained at 23, 60, and 740C for 3 years were examined. X-0287 is 97% 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane explosive, 1.8% Kraton G-1650, and 1.2% B2 was 170. X-0298 is 97.4% explosive, 1.4% Kraton G-1650, and 1.2% Cenco Hi-vac oil. The relaxation associated with the Kraton rubber block glass transition is observed in both X-0287 and X-0298. In the unaged X-0298 it occurs at -590C and in the aged explosive at 500C. This is caused by migration of the oil plasticizer out of the explosive. In X-0287 the Kraton rubber block T/sub g/ is weak and broad due to the presence of the wax plasticizer. X-0287 has a second broad relaxation associated with the melting of the wax from 10 to 650C. The molecular weight of the Kraton binder decreased with increasing accelerated aging temperature. The oil plasticizer had no stabilizing effect, but below its melting point the wax reduced Kraton chain scission considerably. The simple random chain scission model predicted a 20.5 year use-life for X-0298, but X-0287 was stabilized against degradation below the wax melting point

  4. New Accelerating Modules RF Test at TTF

    Kostin, D

    2004-01-01

    Five new accelerating modules were installed into the TTF tunnel as a part of the VUV FEL Linac. They are tested prior to the linac operation. The RF test includes processing of the superconducting cavities, as well as maximum module performance tests. The test procedure and the achieved performance together with the test statistical analysis are presented.

  5. Accelerated Aging Experiments for Capacitor Health Monitoring and Prognostics

    National Aeronautics and Space Administration — This paper discusses experimental setups for health monitoring and prognostics of electrolytic capacitors under nominal operation and accelerated aging conditions....

  6. RHIC sextant test: Accelerator systems and performance

    One sextant of the RHIC Collider was commissioned in early 1997 with beam. We describe here the performance of the accelerator systems, instrumentation subsystems and application software. We also describe a ramping test without beam that took place after the commissioning with beam. Finally, we analyze the implications of accelerator systems performance and their impact on the planning for RHIC installation and commissioning

  7. Testing general relativity on accelerators

    Kalaydzhyan, Tigran

    2015-11-01

    Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyze experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable - maximal energy of the scattered photons - would experience a significant shift in the ambient gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of resolution and expect our work to be a starting point of further high-precision studies on current and future accelerators, such as PETRA, European XFEL and ILC.

  8. Testing general relativity on accelerators

    Tigran Kalaydzhyan

    2015-11-01

    Full Text Available Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyze experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable – maximal energy of the scattered photons – would experience a significant shift in the ambient gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of resolution and expect our work to be a starting point of further high-precision studies on current and future accelerators, such as PETRA, European XFEL and ILC.

  9. Solid oxide materials research accelerated electrochemical testing

    Windisch, C.; Arey, B.

    1995-08-01

    The objectives of this work were to develop methods for accelerated testing of cathode materials for solid oxide fuel cells under selected operating conditions. The methods would be used to evaluate the performance of LSM cathode material.

  10. Testing general relativity on accelerators

    Kalaydzhyan, Tigran

    2015-01-01

    Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyse experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable -- maximal energy of the scattered photons -- would experience a significant shift in the Earth's gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of res...

  11. The electron test accelerator beam injector

    A beam chopper and buncher system has been designed to improve the capture efficiency and reduce the beam spill in the Electron Test Accelerator. The buncher increases the dc beam capture from 30 to 70%. 100% beam transmission through the accelerator structures is obtained with the chopper. This report describes results of experimental tests with the beam injector. Results from computer modeling and from measurements with prototypes that have led to the design of the beam chopper and buncher system are discussed

  12. Potencial fisiológico de sementes de brássicas com ênfase no teste de envelhecimento acelerado Physiological potential of Brassica seeds with emphasis to the accelerated aging test

    Caroline J Costa

    2008-06-01

    different tests for the evaluation of the physiological potential of Brassica seeds with emphasis to the accelerated aging test (AAT. Four lots of cabbage seeds cv. Coração de Boi, four lots of broccoli seeds cv. Piracicaba Precoce and five lots of collard seeds cv. Georgia were used. Tests of germination, first germination counting, seedling emergence, electrical conductivity and accelerated aging were accomplished. In this test three procedures were used: traditional (water, saturated NaCl solution (40 g/100 mL and diluted NaCl solution (11 g/100 mL, at 42°C for 48, 72 and 96 hours. The experiment followed a completely randomized design with four replicates and individual evaluations for each test. The tests of first germination counting and speed of seedling emergence presented potential for evaluation of the physiological potential of cabbage and broccoli seeds. For collard seeds, the tests of seedling emergence and electrical conductivity were the most efficient. The AAT was also efficient in the evaluation of the physiological potential of Brassica seeds. For cabbage, the best distinction among the physiological potential of the seeds through the AAT was obtained following the traditional procedure and with diluted NaCl solution, both for 48 and 72 hours, and with saturated NaCl solution for 72 and 96 hours. For broccoli seeds, all of tested AAT procedures were efficient in the identification of the seed lots of superior quality. For collard seeds, the best results were obtained with the AAT in the traditional methodology for 96 hours and with diluted NaCl solution for 72 hours. It was observed that, in comparison to the use of water, the use of saline solution in the AAT inhibited sensibly the fungi growth and development.

  13. A Comprehensive Review of Accelerated Life Test

    ZHANG Chun-hua; WANG Ya-shun; CHEN Xun; WEN Xi-sen

    2005-01-01

    Accelerated life test (ALT) is an important branch of reliability test and is a focus of research both for statisticians and reliability engineers. The paper outlines the four topics of study embodied in ALT: statistical analysis of constant-stress test, step-stress test and progressive stress test, and optimal design of ALT. It gives a general review of engineering applications of ALT, and points out some possible directions in ALT, gives some suggestions for further study.

  14. Next linear collider test accelerator injector upgrade

    Yeremian, A.D.; Miller, R.H. [Stanford Linear Accelerator Center, CA (United States)

    1995-12-31

    The Next Linear Collider Test Accelerator (NLCTA) is being constructed at SLAC to demonstrate multibunch beam loading compensation, suppression of higher order deflecting modes and measure transverse components of the accelerating fields in X-band accelerating structures. Currently a simple injector which provides the average current necessary for the beam loading compensations studies is under construction. An injector upgrade is planned to produce bunch trains similar to that of the NLC with microbunch intensity, separation and energy spread, identical to that of NLC. We discuss the design of the NLCTA injector upgrade.

  15. Accelerated Aging Experiments for Capacitor Health Monitoring and Prognostics

    Kulkarni, Chetan S.; Celaya, Jose Ramon; Biswas, Gautam; Goebel, Kai

    2012-01-01

    This paper discusses experimental setups for health monitoring and prognostics of electrolytic capacitors under nominal operation and accelerated aging conditions. Electrolytic capacitors have higher failure rates than other components in electronic systems like power drives, power converters etc. Our current work focuses on developing first-principles-based degradation models for electrolytic capacitors under varying electrical and thermal stress conditions. Prognostics and health management for electronic systems aims to predict the onset of faults, study causes for system degradation, and accurately compute remaining useful life. Accelerated life test methods are often used in prognostics research as a way to model multiple causes and assess the effects of the degradation process through time. It also allows for the identification and study of different failure mechanisms and their relationships under different operating conditions. Experiments are designed for aging of the capacitors such that the degradation pattern induced by the aging can be monitored and analyzed. Experimental setups and data collection methods are presented to demonstrate this approach.

  16. Accelerated degradation testing of a photovoltaic module

    Charki, Abdérafi; Laronde, Rémi; Bigaud, David

    2013-01-01

    There are a great many photovoltaic (PV) modules installed around the world. Despite this, not enough is known about the reliability of these modules. Their electrical power output decreases with time mainly as a result of the effects of corrosion, encapsulation discoloration, and solder bond failure. The failure of a PV module is defined as the point where the electrical power degradation reaches a given threshold value. Accelerated life tests (ALTs) are commonly used to assess the reliability of a PV module. However, ALTs provide limited data on the failure of a module and these tests are expensive to carry out. One possible solution is to conduct accelerated degradation tests. The Wiener process in conjunction with the accelerated failure time model makes it possible to carry out numerous simulations and thus to determine the failure time distribution based on the aforementioned threshold value. By this means, the failure time distribution and the lifetime (mean and uncertainty) can be evaluated.

  17. A Statistical Perspective on Highly Accelerated Testing.

    Thomas, Edward V.

    2015-02-01

    Highly accelerated life testing has been heavily promoted at Sandia (and elsewhere) as a means to rapidly identify product weaknesses caused by flaws in the product's design or manufacturing process. During product development, a small number of units are forced to fail at high stress. The failed units are then examined to determine the root causes of failure. The identification of the root causes of product failures exposed by highly accelerated life testing can instigate changes to the product's design and/or manufacturing process that result in a product with increased reliability. It is widely viewed that this qualitative use of highly accelerated life testing (often associated with the acronym HALT) can be useful. However, highly accelerated life testing has also been proposed as a quantitative means for "demonstrating" the reliability of a product where unreliability is associated with loss of margin via an identified and dominating failure mechanism. It is assumed that the dominant failure mechanism can be accelerated by changing the level of a stress factor that is assumed to be related to the dominant failure mode. In extreme cases, a minimal number of units (often from a pre-production lot) are subjected to a single highly accelerated stress relative to normal use. If no (or, sufficiently few) units fail at this high stress level, some might claim that a certain level of reliability has been demonstrated (relative to normal use conditions). Underlying this claim are assumptions regarding the level of knowledge associated with the relationship between the stress level and the probability of failure. The primary purpose of this document is to discuss (from a statistical perspective) the efficacy of using accelerated life testing protocols (and, in particular, "highly accelerated" protocols) to make quantitative inferences concerning the performance of a product (e.g., reliability) when in fact there is lack-of-knowledge and uncertainty concerning

  18. RHIC Sextant Test - Accelerator Systems and Performance

    Pilat, F.; Ahrens, L.; Brown, K.; Connolly, R.; dell, G. F.; Fischer, W.; Kewisch, J.; Mackay, W.; Mane, V.; Peggs, S.; Satogata, T.; Tepikian, S.; Thompson, P.; Trbojevic, D.; Tsoupas, N.; Wei, J.

    1997-05-01

    One sextant of the RHIC collider and the full AtR (AGS to RHIC) transfer line have been commissioned in early 1997 with beam. We describe here the design and performance of the accelerator systems during the test, such as the magnet and power supply systems, instrumentation subsystems and application software. After reviewing the main milestones of the commissioning we describe a ramping test without beam that took place after the commissioning with beam. Finally, we analyze the implications of accelerator systems preformance and their impact on the plannig for RHIC installation and commissioning.

  19. Test Stand for Linear Induction Accelerator Optimization

    Lawrence Livermore National Laboratory has designed and constructed a test stand to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell. The goal is to create a more mono-energetic electron beam that will create an x-ray source with a smaller spot size. Studying the interaction of the beam and pulse-power system with the accelerator cell will improve the design of high-current accelerators at Livermore and elsewhere. On the test stand, a standard FXR cell is driven by a flexible pulse-power system and the beam current is simulated with a switched center conductor. The test stand is fully instrumented with high-speed digitizers to document the effect of impedance mismatches when the cell is operated under various full-voltage conditions. A time-domain reflectometry technique was also developed to characterize the beam and cell interactions by measuring the impedance of the accelerator and pulse-power component. Computer models are being developed in parallel with the testing program to validate the measurements and evaluate different design changes. Both 3D transient electromagnetic and circuit models are being used

  20. The BNL Accelerator Test Facility control system

    Described is the VAX/CAMAC-based control system for Brookhaven National Laboratory's Accelerator Test Facility, a laser/linac research complex. Details of hardware and software configurations are presented along with experiences of using Vsystem, a commercial control system package

  1. Early Telomerase Inactivation Accelerates Aging Independently of Telomere Length

    Xie, Zhengwei; Jay, Kyle A.; Smith, Dana L.; Zhang, Yi; Liu, Zairan; Zheng, Jiashun; Tian, Ruilin; Li, Hao; Blackburn, Elizabeth

    2015-01-01

    Telomerase is required for long-term telomere maintenance and protection. Using single budding yeast mother cell analyses we found that, even Early after Telomerase Inactivation (ETI), yeast mother cells show transient DNA Damage Response (DDR) episodes, stochastically altered cell cycle dynamics, and accelerated mother cell aging. The acceleration of ETI mother cell aging was not explained by increased reactive oxygen species (ROS), Sir protein perturbation, or deprotected telomeres. ETI occ...

  2. Accelerated food source location in aging Drosophila

    Egenriether, Sada M; Chow, Eileen S.; Krauth, Nathalie; Giebultowicz, Jadwiga M.

    2015-01-01

    Adequate energy stores are essential for survival, and sophisticated neuroendocrine mechanisms evolved to stimulate foraging in response to nutrient deprivation. Food search behavior is usually investigated in young animals, and it is not known how aging alters this behavior. To address this question in Drosophila melanogaster, we compared the ability to locate food by olfaction in young and old flies using a food-filled trap. As aging is associated with a decline in motor functions, learning...

  3. Pathology of Mouse Models of Accelerated Aging.

    Harkema, L; Youssef, S A; de Bruin, A

    2016-03-01

    Progeroid mouse models display phenotypes in multiple organ systems that suggest premature aging and resemble features of natural aging of both mice and humans. The prospect of a significant increase in the global elderly population within the next decades has led to the emergence of "geroscience," which aims at elucidating the molecular mechanisms involved in aging. Progeroid mouse models are frequently used in geroscience as they provide insight into the molecular mechanisms that are involved in the highly complex process of natural aging. This review provides an overview of the most commonly reported nonneoplastic macroscopic and microscopic pathologic findings in progeroid mouse models (eg, osteoporosis, osteoarthritis, degenerative joint disease, intervertebral disc degeneration, kyphosis, sarcopenia, cutaneous atrophy, wound healing, hair loss, alopecia, lymphoid atrophy, cataract, corneal endothelial dystrophy, retinal degenerative diseases, and vascular remodeling). Furthermore, several shortcomings in pathologic analysis and descriptions of these models are discussed. Progeroid mouse models are valuable models for aging, but thorough knowledge of both the mouse strain background and the progeria-related phenotype is required to guide interpretation and translation of the pathology data. PMID:26864891

  4. Manufacturing and Testing of Accelerator Superconducting Magnets

    Rossi, L

    2014-01-01

    Manufacturing of superconducting magnet for accelerators is a quite complex process that is not yet fully industrialized. In this paper, after a short history of the evolution of the magnet design and construction, we review the main characteristics of the accelerator magnets having an impact on the construction technology. We put in evidence how the design and component quality impact on construction and why the final product calls for a total-quality approach. LHC experience is widely discussed and main lessons are spelled out. Then the new Nb3Sn technology, under development for the next generation magnet construction, is outlined. Finally, we briefly review the testing procedure of accelerator superconducting magnets, underlining the close connection with the design validation and with the manufacturing process.

  5. Test Particles with Acceleration-Dependent Lagrangian

    Toller, M

    2006-01-01

    We consider a classical test particle subject to electromagnetic and gravitational fields, described by a Lagrangian depending on the acceleration and on a fundamental length. We associate to the particle a moving local reference frame and we study its trajectory in the principal fibre bundle of all the Lorentz frames. We discuss in this framework the general form of the Lagrange equations and the connection between symmetries and conservation laws (Noether theorem). We apply these results to a model, already discussed by other authors, which implies an upper bound to the proper acceleration and to another new model in which a similar quantity, called ``pseudo-acceleration'', is bounded. With some simple choices of the fields, we illustrate some other interesting properties of the models and we show that unwanted features may appear, as instable run-away solutions and unphysical values of the energy-momentum or of the velocity.

  6. Accelerated food source location in aging Drosophila.

    Egenriether, Sada M; Chow, Eileen S; Krauth, Nathalie; Giebultowicz, Jadwiga M

    2015-10-01

    Adequate energy stores are essential for survival, and sophisticated neuroendocrine mechanisms evolved to stimulate foraging in response to nutrient deprivation. Food search behavior is usually investigated in young animals, and it is not known how aging alters this behavior. To address this question in Drosophila melanogaster, we compared the ability to locate food by olfaction in young and old flies using a food-filled trap. As aging is associated with a decline in motor functions, learning, and memory, we expected that aged flies would take longer to enter the food trap than their young counterparts. Surprisingly, old flies located food with significantly shorter latency than young ones. Robust food search behavior was associated with significantly lower fat reserves and lower starvation resistance in old flies. Food-finding latency (FFL) was shortened in young wild-type flies that were starved until their fat was depleted but also in heterozygous chico mutants with reduced insulin receptor activity and higher fat deposits. Conversely, food trap entry was delayed in old flies with increased insulin signaling. Our results suggest that the difference in FFL between young and old flies is linked to age-dependent differences in metabolic status and may be mediated by reduced insulin signaling. PMID:26102220

  7. Development of an accelerated aging method for evaluation of long-term irradiation effects on UHMWPE implants

    A general scheme for developing an accelerated aging method for irradiated biomaterials is proposed. Using UHMWPE implants as an example, an accelerated thermal diffusion oxidative aging (ATDOA) method has been developed. The method requires an optimum initial heating rate and an optimum aging temperature to accelerate oxidation reactions. Based upon oxidation-induced material property changes (crystallinity by DSC, tensile properties by ASTM D638 tensile test, and oxidation index by FTIR), correlations between accelerated aging time, shelf aging time, and implantation time can be obtained. The new ATDOA method allows a rapid evaluation of long-term irradiation effects on the material properties of UHMWPE implants

  8. Tests of compressed geometry acceleration tubes in the Oak Ridge 25URC tandem accelerator

    In an effort to further improve voltage performance of the Oak Ridge 25URC accelerator, the original acceleration tubes will be replaced with NEC compressed geometry acceleration tubes. In this paper, we report on tests in the 25URC accelerator of two prototype compressed geometry acceleration tube designs. One of the designs utilizes a novel aperture which provides enhanced electron and ion trapping

  9. Accelerated Aging with Electrical Overstress and Prognostics for Power MOSFETs

    Saha, Sankalita; Celaya, Jose Ramon; Vashchenko, Vladislav; Mahiuddin, Shompa; Goebel, Kai F.

    2011-01-01

    Power electronics play an increasingly important role in energy applications as part of their power converter circuits. Understanding the behavior of these devices, especially their failure modes as they age with nominal usage or sudden fault development is critical in ensuring efficiency. In this paper, a prognostics based health management of power MOSFETs undergoing accelerated aging through electrical overstress at the gate area is presented. Details of the accelerated aging methodology, modeling of the degradation process of the device and prognostics algorithm for prediction of the future state of health of the device are presented. Experiments with multiple devices demonstrate the performance of the model and the prognostics algorithm as well as the scope of application. Index Terms Power MOSFET, accelerated aging, prognostics

  10. BNL ACCELERATOR TEST FACILITY CONTROL SYSTEM UPGRADE.

    MALONE,R.; BEN-ZVI,I.; WANG,X.; YAKIMENKO,V.

    2001-06-18

    Brookhaven National Laboratory's Accelerator Test Facility (ATF) has embarked on a complete upgrade of its decade old computer system. The planned improvements affect every major component: processors (Intel Pentium replaces VAXes), operating system (Linux/Real-Time Linux supplants OpenVMS), and data acquisition equipment (fast Ethernet equipment replaces CAMAC serial highway.) This paper summarizes the strategies and progress of the upgrade along with plans for future expansion.

  11. Test Particles with Acceleration-Dependent Lagrangian

    Toller, M.

    2005-01-01

    We consider a classical test particle subject to electromagnetic and gravitational fields, described by a Lagrangian depending on the acceleration and on a fundamental length. We associate to the particle a moving local reference frame and we study its trajectory in the principal fibre bundle of all the Lorentz frames. We discuss in this framework the general form of the Lagrange equations and the connection between symmetries and conservation laws (Noether theorem). We apply these results to...

  12. Vacuum system for Advanced Test Accelerator

    Denhoy, B.S.

    1981-09-03

    The Advanced Test Accelerator (ATA) is a pulsed linear electron beam accelerator designed to study charged particle beam propagation. ATA is designed to produce a 10,000 amp 50 MeV, 70 ns electron beam. The electron beam acceleration is accomplished in ferrite loaded cells. Each cell is capable of maintaining a 70 ns 250 kV voltage pulse across a 1 inch gap. The electron beam is contained in a 5 inch diameter, 300 foot long tube. Cryopumps turbomolecular pumps, and mechanical pumps are used to maintain a base pressure of 2 x 10/sup -6/ torr in the beam tube. The accelerator will be installed in an underground tunnel. Due to the radiation environment in the tunnel, the controlling and monitoring of the vacuum equipment, pressures and temperatures will be done from the control room through a computer interface. This paper describes the vacuum system design, the type of vacuum pumps specified, the reasons behind the selection of the pumps and the techniques used for computer interfacing.

  13. Vacuum system for Advanced Test Accelerator

    The Advanced Test Accelerator (ATA) is a pulsed linear electron beam accelerator designed to study charged particle beam propagation. ATA is designed to produce a 10,000 amp 50 MeV, 70 ns electron beam. The electron beam acceleration is accomplished in ferrite loaded cells. Each cell is capable of maintaining a 70 ns 250 kV voltage pulse across a 1 inch gap. The electron beam is contained in a 5 inch diameter, 300 foot long tube. Cryopumps turbomolecular pumps, and mechanical pumps are used to maintain a base pressure of 2 x 10-6 torr in the beam tube. The accelerator will be installed in an underground tunnel. Due to the radiation environment in the tunnel, the controlling and monitoring of the vacuum equipment, pressures and temperatures will be done from the control room through a computer interface. This paper describes the vacuum system design, the type of vacuum pumps specified, the reasons behind the selection of the pumps and the techniques used for computer interfacing

  14. Wet and dry accelerated aging tests in a spray chamber to understand the effects of acid rain frequencies on bronze corrosion

    Gianni, Liliana; Cavallini, Mauro; Natali, Stefano; Adriaens, Annemie

    2013-01-01

    We have conducted controlled laboratory experiments using a series of bronze alloys exposed to frequent, repeated wet and dry cycles, to simulate frequent acid rain exposure and study the resultant corrosion processes in bronze artifacts exposed to an outdoor urban environment. To simulate rainwater and condensation, a spray chamber for the corrosion tests was assembled, which delivered homogeneous vapor diffusion and drop deposition. Three bi-component bronzes, with 3%, 7% and 20% tin conten...

  15. 加速老化试验对有机硅胶封装材料光学性质的影响%The Effect of Accelerated Aging Tests on the Optical Properties of Silicone Encapsulant

    韩新月; 王一平; 朱丽

    2013-01-01

    The spectral transmittance of two silicones encapsulant was investigated before and after exposure to three accelerated aging tests. The results showed that both silicone A and silicone B exhibited excellent optical transparency over the spectrum that silicon solar cells absorb strongly. The spectral transmittance of silicone A and silicone B was essentially unchanged after exposure DI water at room temperature for 130 days. However, the results indicated that there was a little change in the transmittance of silicone A over 300 ~ 400 nm during damp heat test, but not found in thermal cycling exposure. The decrease in transmittance of silicone B over 300 ~ 450 nm was detected both in damp heat and thermal cycling exposures. The transmittance of both silicone A and silicone B in UV-Vis wavelength after exposure to accelerated aging tests was still higher than that of EVA. Furthermore, it was identified that silicone B has a higher capacity to absorb moisture than the silicone A. The moisture could scatter the incident light during transmittance measurement, thus reduced the transmittance of the silicone samples.%测试分析了2种有机硅胶封装材料在3种加速老化试验前、后的光谱透过率.结果表明,2种有机硅胶在硅太阳电池的工作波段的透过率都很高.经过130d的去离子水浸没后,2种硅胶的光谱透过率都没有变化;硅胶A仅在湿热测试中于300 ~ 400nm波段的透过率有稍许变化,而在热循环测试中其光学性质很稳定;硅胶B在两种测试中于300~ 450nm波段的透过率都有少许降低;不过,两种硅胶经老化试验后的紫外-可见光波段的透过率还是高于EVA的.其中硅胶B对湿气的吸收比硅胶A强,湿气可以散射入射光,进而在透过率测试时降低硅胶样品的透过率.

  16. Accelerated Leach Test(s) Program: Annual report

    A computerized data base of LLW leaching data has been developed. Long-term tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms containing simulated wastes are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms

  17. Accelerated Leach Test(s) Program: Annual report

    Dougherty, D.R.; Pietrzak, R.F.; Fuhrmann, M.; Colombo, P.

    1986-09-01

    A computerized data base of LLW leaching data has been developed. Long-term tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms containing simulated wastes are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms.

  18. Stripline kicker for integrable optics test accelerator

    Antipov, Sergey A.; Didenko, Alexander; Lebedev, Valeri; Valishev, Alexander

    2016-01-01

    We present a design of a stripline kicker for Integrable Optics Test Accelerator (IOTA). For its experimental program IOTA needs two full-aperture kickers, capable to create an arbitrary controllable kick in 2D. For that reason their strengths are variable in a wide range of amplitudes up to 16 mrad, and the pulse length 100 ns is less than a revolution period for electrons. In addition, the kicker should have a physical aperture of 40 mm for a proposed operation with proton beam, and an oute...

  19. Consideration on A.C. electric motor subjected to thermal and radiation accelerated ageing

    In the containment building of a nuclear reactor there are many types of equipment, such as motors, valve and transducers. Electric motors used in nuclear power stations operate under specific environmental conditions. These conditions are determinate by temperature, humidity, pressure, radiation and they may be normal conditions in service, or may be accident conditions occur during the postulated LOCA event. The testing of electric motors capability to meet and exceed the required performances under specific operating environmental conditions all along its operating life implies the performing of a sequence of tests in which the environmental conditions are simulated in a accelerated manner followed by accident simulation tests. Simulating the ageing position of the test sequence is more difficult because of the problem of extrapolating the results of short term accelerated laboratory experiments to the long term exposure (up to 30 years) that actually occur in a nuclear plant. Thermally induced ageing is the most frequently used ageing stress and also the most easily. The insulated system of a motor ageing under the influence of temperature and high - energy radiation can suffer important changes in its electro-insulating properties. Thus, by way of accelerated ageing motors are brought under conditions equivalent to those at the end of their service life, in a relatively short time. Accelerated ageing enables a shorting of electric motor performance evaluation time. (author)

  20. Laboratory Test of Newton's Second Law for Small Accelerations

    We have tested the proportionality of force and acceleration in Newton's second law, F=ma, in the limit of small forces and accelerations. Our tests reach well below the acceleration scales relevant to understanding several current astrophysical puzzles such as the flatness of galactic rotation curves, the Pioneer anomaly, and the Hubble acceleration. We find good agreement with Newton's second law at accelerations as small as 5x10-14 m/s2

  1. Accelerated brain aging in schizophrenia : A longitudinal pattern recognition study

    Schnack, Hugo G.; Van Haren, Neeltje E M; Nieuwenhuis, Mireille; Pol, Hilleke E Hulshoff; Cahn, Wiepke; Kahn, René S.

    2016-01-01

    OBJECTIVE: Despite the multitude of longitudinal neuroimaging studies that have been published, a basic question on the progressive brain loss in schizophrenia remains unaddressed: Does it reflect accelerated aging of the brain, or is it caused by a fundamentally different process? The authors used

  2. Life evaluation of insulating materials for electric cable by accelerated thermal-radiation combined aging. 2

    Radiation-and-thermal-combined degradation of some kinds of cable insulating and jacketing materials was evaluated by accelerated aging tests. Plasticized polyvinyl chloride (PVC), silicone rubber, crosslinked and non-crosslinked halogen-free flame-retardant polyolefins (NH-XLPO and NH-PO) and ethylene-propylene rubber (EP rubber) of experimental formulation were degraded at accelerated rates, that are 50-1000 times the degradation rate under standard conditions (e.g.; 1Gy/h, 50degC), and a method to assess the lifetime of these materials under standard conditions was studied. The degradation was investigated by measuring tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for these materials were in proportion to the increase in accelerated rate. The PVC lifetime estimated from sequential aging tests had a tendency to extend beyond that from simultaneous aging tests, while the lifetime of other materials estimated from both aging tests were coincident. Furthermore, the influence of antioxidant on the degradation in EP rubber under radiation-and-thermal combined condition was studied. A lifetime estimated for EP rubber improved γ-radiation resistance with a certain anti-oxidant extended remarkably even under such condition. (J.P.N.)

  3. Cognitive and brain function in adults with Type 1 diabetes mellitus : is there evidence of accelerated ageing?

    Johnston, Harriet N.

    2013-01-01

    The physical complications of Type 1 diabetes mellitus (T1DM) have been understood as an accelerated ageing process (Morley, 2008). Do people with T1DM also experience accelerated cognitive and brain ageing? Using findings from research of the normal cognitive and brain ageing process and conceptualized in theories of the functional brain changes in cognitive ageing, a combination of cognitive testing and functional magnetic resonance imaging (fMRI) techniques were used to evaluate evidence o...

  4. Characterization and Accelerated Ageing of UHMWPE Used in Orthopedic Prosthesis by Peroxide

    Herman Mansur; Alexandra Mansur; Magda Rocha

    2009-01-01

    Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important mechanical properties to extend the longevity of knee prostheses. Though accelerated in vitro protocols have been developed to test the relative oxidation resistance of various types of UHMWPE, its mechanism is not accurately understood yet. Thus, in the present study an accelerated ageing ...

  5. Induction accelerator test module for HIF

    An induction linac test module suitable for investigating the drive requirements and the longitudinal coupling impedance of a high-power ion induction linac has been constructed by the Heavy Ion Fusion (HIF) group at LBL. The induction linac heavy ion driver for inertial confinement fusion (ICF) as presently envisioned uses multiple parallel beams which are transported in separate focusing channels but accelerated together in the induction modules. The resulting induction modules consequently have large beam apertures-1--2 meters in diameter- and correspondingly large outside diameters. The module geometry is related to a low-frequency ''gap capacity'' and high-frequency structural resonances, which are affected by the magnetic core loading and the module pulser impedance. A description of the test module and preliminary results are presented. 3 figs

  6. Flame Acceleration Tests with Hydrogen Combustions

    According to the domestic and foreign regulations, a detonation or DDT (deflagration to detonation transition) by a hydrogen combustion should be prohibited to occur in a containment of a nuclear power plant. A hydrogen control in the IRWST(Incontainment Refueling Water Storage Tank) under a severe accident still remains a debatable issue to be solved in APR1400. The characteristics of the hydrogen flame in the IRWST expected during the station black-out (SBO) and total loss of feed water (LOFW) accidents have been evaluated based on a sigma-lambda criteria from the simulation results by the numerical codes such as GASFLOW. And it was found that hydrogen mixture was non-flammable most of the accident time when the non-condensed steam was released into the free volume of the IRWST, but there existed a small period of time with a high possibility of a flame acceleration during the SBO accident because most of the steam discharged from sparger was well condensed. Therefore, detail analysis and experiment of the hydrogen flame should be required to fix a DDT possibility by the hydrogen combustion in the IRWST of the APR1400. Most experiments on the hydrogen combustion have been limited only to straight pipes or channels. However, the hydrogen flame acceleration phenomena in the IRWST with a closed annular path may be different from those in the straight path in respect to a centrifugal force and degree of freedom in flame propagation etc. So, an experiment of hydrogen combustion in a closed annular chamber is needed to find out the geometrical effect on the flame propagation and to validate the numerical results. KAERI has been performing the experiments of the hydrogen combustion in the IRWST. As the fist stage, flame acceleration tests with the hydrogen combustions are studied preliminarily for a circular straight pipe to confirm the characteristics hydrogen flame propagation, and to evaluate flame detection systems

  7. Accelerated Strength Testing of Thermoplastic Composites

    Reeder, J. R.; Allen, D. H.; Bradley, W. L.

    1998-01-01

    Constant ramp strength tests on unidirectional thermoplastic composite specimens oriented in the 90 deg. direction were conducted at constant temperatures ranging from 149 C to 232 C. Ramp rates spanning 5 orders of magnitude were tested so that failures occurred in the range from 0.5 sec. to 24 hrs. (0.5 to 100,000 MPa/sec). Below 204 C, time-temperature superposition held allowing strength at longer times to be estimated from strength tests at shorter times but higher temperatures. The data indicated that a 50% drop in strength might be expected for this material when the test time is increased by 9 orders of magnitude. The shift factors derived from compliance data applied well to the strength results. To explain the link between compliance and strength, a viscoelastic fracture model was investigated. The model, which used compliance as input, was found to fit the strength data only if the critical fracture energy was allowed to vary with temperature reduced stress rate. This variation in the critical parameter severely limits its use in developing a robust time-dependent strength model. The significance of this research is therefore seen as providing both the indication that a more versatile acceleration method for strength can be developed and the evidence that such a method is needed.

  8. Hurricane Isabel gives accelerators a severe test

    Hurricane Isabel was at category five--the most violent on the Saffir-Simpson scale of hurricane strength--when it began threatening the central Atlantic seaboard of the US. Over the course of several days, precautions against the extreme weather conditions were taken across the Jefferson Lab site in south-east Virginia. On 18 September 2003, when Isabel struck North Carolina's Outer Banks and moved northward, directly across the region around the laboratory, the storm was still quite destructive, albeit considerably reduced in strength. The flood surge and trees felled by wind substantially damaged or even devastated buildings and homes, including many belonging to Jefferson Lab staff members. For the laboratory itself, Isabel delivered an unplanned and severe challenge in another form: a power outage that lasted nearly three-and-a-half days, and which severely tested the robustness of Jefferson Lab's two superconducting machines, the Continuous Electron Beam Accelerator Facility (CEBAF) and the superconducting radiofrequency ''driver'' accelerator of the laboratory's free-electron laser. Robustness matters greatly for science at a time when microwave superconducting linear accelerators (linacs) are not only being considered, but in some cases already being built for projects such as neutron sources, rare-isotope accelerators, innovative light sources and TeV-scale electron-positron linear colliders. Hurricane Isabel interrupted a several-week-long maintenance shutdown of CEBAF, which serves nuclear and particle physics and represents the world's pioneering large-scale implementation of superconducting radiofrequency (SRF) technology. The racetrack-shaped machine is actually a pair of 500-600 MeV SRF linacs interconnected by recirculation arc beamlines. CEBAF delivers simultaneous beams at up to 6 GeV to three experimental halls. An imminent upgrade will double the energy to 12 GeV and add an extra hall for ''quark confinement'' studies. On a smaller scale

  9. Cognitive deterioration in adult epilepsy: Does accelerated cognitive ageing exist?

    Breuer, L E M; Boon, P; Bergmans, J W M; Mess, W H; Besseling, R M H; de Louw, A; Tijhuis, A G; Zinger, S; Bernas, A; Klooster, D C W; Aldenkamp, A P

    2016-05-01

    A long-standing concern has been whether epilepsy contributes to cognitive decline or so-called 'epileptic dementia'. Although global cognitive decline is generally reported in the context of chronic refractory epilepsy, it is largely unknown what percentage of patients is at risk for decline. This review is focused on the identification of risk factors and characterization of aberrant cognitive trajectories in epilepsy. Evidence is found that the cognitive trajectory of patients with epilepsy over time differs from processes of cognitive ageing in healthy people, especially in adulthood-onset epilepsy. Cognitive deterioration in these patients seems to develop in a 'second hit model' and occurs when epilepsy hits on a brain that is already vulnerable or vice versa when comorbid problems develop in a person with epilepsy. Processes of ageing may be accelerated due to loss of brain plasticity and cognitive reserve capacity for which we coin the term 'accelerated cognitive ageing'. We believe that the concept of accelerated cognitive ageing can be helpful in providing a framework understanding global cognitive deterioration in epilepsy. PMID:26900650

  10. Stripline kicker for integrable optics test accelerator

    Antipov, Sergey A.; Didenko, Alexander; Lebedev, Valeri; Valishev, Alexander

    2016-06-30

    We present a design of a stripline kicker for Integrable Optics Test Accelerator (IOTA). For its experimental program IOTA needs two full-aperture kickers, capable to create an arbitrary controllable kick in 2D. For that reason their strengths are variable in a wide range of amplitudes up to 16 mrad, and the pulse length 100 ns is less than a revolution period for electrons. In addition, the kicker should have a physical aperture of 40 mm for a proposed operation with proton beam, and an outer size of 70 mm to fit inside existing quadrupole magnets to save space in the ring. Computer simulations using CST Microwave Studio show high field uniformity and wave impedance close to 50 {\\Omega}.

  11. Planck scale gravity test with accelerators

    Gharibyan, Vahagn

    2012-07-15

    Quantum or torsion gravity models predict unusual properties of space-time at very short distances. In particular, near the Planck length, around 10{sup -35} m, empty space may behave as a crystal, singly or doubly refractive. However, this hypothesis remains uncheckable for any direct measurement since the smallest distance accessible in experiment is about 10{sup -19} m at the LHC. Here I propose a laboratory test to measure the space refractivity and birefringence induced by gravity. A sensitivity from 10{sup -31} m down to the Planck length could be reached at existent GeV and future TeV energy lepton accelerators using laser Compton scattering. There are already experimental hints for gravity signature at distances approaching the Planck length by 5-7 orders of magnitude, derived from SLC and HERA data.

  12. Stripline kicker for integrable optics test accelerator

    Antipov, Sergey A; Lebedev, Valeri; Valishev, Alexander

    2016-01-01

    We present a design of a stripline kicker for Integrable Optics Test Accelerator (IOTA). For its experimental program IOTA needs two full-aperture kickers, capable to create an arbitrary controllable kick in 2D. For that reason their strengths are variable in a wide range of amplitudes up to 16 mrad, and the pulse length 100 ns is less than a revolution period for electrons. In addition, the kicker should have a physical aperture of 40 mm for a proposed operation with proton beam, and an outer size of 70 mm to fit inside existing quadrupole magnets to save space in the ring. Computer simulations using CST Microwave Studio show high field uniformity and wave impedance close to 50 {\\Omega}.

  13. Planck scale gravity test with accelerators

    Quantum or torsion gravity models predict unusual properties of space-time at very short distances. In particular, near the Planck length, around 10-35 m, empty space may behave as a crystal, singly or doubly refractive. However, this hypothesis remains uncheckable for any direct measurement since the smallest distance accessible in experiment is about 10-19 m at the LHC. Here I propose a laboratory test to measure the space refractivity and birefringence induced by gravity. A sensitivity from 10-31 m down to the Planck length could be reached at existent GeV and future TeV energy lepton accelerators using laser Compton scattering. There are already experimental hints for gravity signature at distances approaching the Planck length by 5-7 orders of magnitude, derived from SLC and HERA data.

  14. Accelerated Creep Testing of High Strength Aramid Webbing

    Jones, Thomas C.; Doggett, William R.; Stnfield, Clarence E.; Valverde, Omar

    2012-01-01

    A series of preliminary accelerated creep tests were performed on four variants of 12K and 24K lbf rated Vectran webbing to help develop an accelerated creep test methodology and analysis capability for high strength aramid webbings. The variants included pristine, aged, folded and stitched samples. This class of webbings is used in the restraint layer of habitable, inflatable space structures, for which the lifetime properties are currently not well characterized. The Stepped Isothermal Method was used to accelerate the creep life of the webbings and a novel stereo photogrammetry system was used to measure the full-field strains. A custom MATLAB code is described, and used to reduce the strain data to produce master creep curves for the test samples. Initial results show good correlation between replicates; however, it is clear that a larger number of samples are needed to build confidence in the consistency of the results. It is noted that local fiber breaks affect the creep response in a similar manner to increasing the load, thus raising the creep rate and reducing the time to creep failure. The stitched webbings produced the highest variance between replicates, due to the combination of higher local stresses and thread-on-fiber damage. Large variability in the strength of the webbings is also shown to have an impact on the range of predicted creep life.

  15. Development of an accelerated test for Internal Sulfate Attack study

    Khelil Nacim

    2014-04-01

    Full Text Available Internal Sulfate Attack (ISA is a pathology that occurs under certain conditions in concrete having undergone heating above 70 °C at early age (through heating in pre-casting industry or due to hydration in large concrete parts. This reaction deemed very slow, numerous methods to speed up reactions leading to delayed ettringite formation have been developed. These methods are all based on the material damage. Another type of test is currently under development. It is based on rehabilitation techniques such as electrochemical chloride extraction (ECE in order to accelerate the leaching of alkalis that could be one of the triggers of the pathology. The study presented in this paper focused on concrete specimens prepared from cement (CEM I 52.5 N enriched with Na2SO4. These concretes have undergone a heat treatment typical of those used in precast plants (up to 24 hours with a maximum temperature of 80 °C. Various paths were explored for the development of the accelerated test. The first results showed that it was necessary to use a removable titanium anode ruthenium anode instead of stainless steel embedded in the concrete. Then tests with de-ionized water as the solute to the cathode did not accelerate the onset of expansions. The experiment has been modified and potassium carbonate was added to the solution. This modification didn’t show any significant improvement, and other experiments are being carried out to explain this result.

  16. Accelerated aging and controlled deterioration for the determination of the physiological potential of onion seeds

    Rodo Angelica Brod

    2003-01-01

    Full Text Available International research on vegetable seed vigor is not at the same level attained for grain crops species. This study was conducted to identify reliable procedures for the accelerated aging and controlled deterioration tests to rank onion (Allium cepa L. seed lots according to their physiological potential. Six seed lots of the cultivars Aurora and Petroline were evaluated in the laboratory for germination, first count, seedling vigor classification, traditional and saturated salt accelerated aging (41masculineC / 48 and 72 h, controlled deterioration (24% of water / 45masculineC / 24 h and seedling emergence tests. Seed moisture content after the saturated salt accelerated aging test was lower and uniform, which is considered an important advantage in comparison to the traditional procedure. The saturated salt accelerated aging (41masculineC / 48 and 72 h and controlled deterioration (moisture content adjusted to 24% / 45masculineC / 24 h tests were the best procedures to assess the physiological potential of onion seeds, and are indicated for use in quality control programs.

  17. Accelerated Thermal Aging Studies on Natural Rubber in Seismic Isolation Bearings

    Most rubbers harden and eventually become brittle owing to the aging process. The thermal aging is known to be the most significant factor in the deterioration of rubber materials. The ambient temperature substantially increases the stiffness and damping of the rubber bearings, even at room temperature. Under low temperature, a long duration of exposure increases both quantities. High temperatures have a significant effect on the mechanical properties of rubber bearings. This study focuses on the aging behavior of natural rubber material used in seismic isolation bearings by accelerated heat exposure tests. Accelerated thermal aging tests were carried out for a natural rubber material, and its lifetime was predicted. The deterioration of the rubber material is more significant at high ambient temperature. In addition, the deterioration of rubber influences the adhesion between the rubber and the steel plates. Dynamic properties of the rubber will be a critical factor for defining the service time of seismic isolation bearings

  18. Electrochemical migration technique to accelerate ageing of cementitious materials

    Abbas Z.; Tang L; Babaahmadi A.

    2013-01-01

    Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for acceler...

  19. ACCELERATED AGEING EFFECTS ON CURCUBITEA PEPO SEED OIL

    D. Mampouya A. H. W. Nakavoua; A.N. Loumouamou; Th Silou; Chalard, P.; V. Verney; Guyot, G; J. C. Chalchat; G. Figuérédo

    2013-01-01

    Accelerated ageing of curcubitea pepo seed oil was followed by simulation of UV (light) and ambiant oxygen actions held separately then simultaneously in order to know the effects of these parameters on this oil resistance to deterioraton. Nine withdrawals had undergone analyses by titrimetry supported by spectroscopic analyses notably MIR (Medium Infrared), DSC (Differential Scanning Calorimetry) and also a gas chromatography for the composition in FA. This study has showed that pumpkin seed...

  20. Accelerated testing statistical models, test plans, and data analysis

    Nelson, Wayne B

    2009-01-01

    The Wiley-Interscience Paperback Series consists of selected books that have been made more accessible to consumers in an effort to increase global appeal and general circulation. With these new unabridged softcover volumes, Wiley hopes to extend the lives of these works by making them available to future generations of statisticians, mathematicians, and scientists. "". . . a goldmine of knowledge on accelerated life testing principles and practices . . . one of the very few capable of advancing the science of reliability. It definitely belongs in every bookshelf on engineering.""-Dev G.

  1. Accelerated ageing and renal dysfunction links lower socioeconomic status and dietary phosphate intake

    McClelland, Ruth; Christensen, Kelly; Mohammed, Suhaib; McGuinness, Dagmara; Cooney, Josephine; Bakshi, Andisheh; Demou, Evangelia; MacDonald, Ewan; Caslake, Muriel; Stenvinkel, Peter; Shiels, Paul G.

    2016-01-01

    Background We have sought to explore the impact of dietary Pi intake on human age related health in the pSoBid cohort (n=666) to explain the disparity between health and deprivation status in this cohort. As hyperphosphataemia is a driver of accelerated ageing in rodent models of progeria we tested whether variation in Pi levels in man associate with measures of biological ageing and health. Results We observed significant relationships between serum Pi levels and markers of biological age (telomere length (p=0.040) and DNA methylation content (p=0.028), gender and chronological age (p=0.032). When analyses were adjusted for socio-economic status and nutritional factors, associations were observed between accelerated biological ageing (telomere length, genomic methylation content) and dietary derived Pi levels among the most deprived males, directly related to the frequency of red meat consumption. Conclusions Accelerated ageing is associated with high serum Pi levels and frequency of red meat consumption. Our data provide evidence for a mechanistic link between high intake of Pi and age-related morbidities tied to socio-economic status. PMID:27132985

  2. Electrochemical migration technique to accelerate ageing of cementitious materials

    Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen's micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium. (authors)

  3. Electrochemical migration technique to accelerate ageing of cementitious materials

    Babaahmadi, A.; Tang, L.; Abbas, Z.

    2013-07-01

    Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen's micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  4. Electrochemical migration technique to accelerate ageing of cementitious materials

    Abbas Z.

    2013-07-01

    Full Text Available Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen’s micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  5. Beam Physics of Integrable Optics Test Accelerator at Fermilab

    Nagaitsev, S.; Valishev, A.; Danilov, V. V.; Shatilov, D. N.

    2013-01-01

    Fermilab's Integrable Optics Test Accelerator is an electron storage ring designed for testing advanced accelerator physics concepts, including implementation of nonlinear integrable beam optics and experiments on optical stochastic cooling. The machine is currently under construction at the Advanced Superconducting Test Accelerator facility. In this report we present the goals and the current status of the project, and describe the details of machine design. In particular, we concentrate on ...

  6. Operation of the Brookhaven national laboratory accelerator test facility

    Early operation of the 50 MeV high brightness electron linac of the Accelerator Test Facility is described along with experimental data. This facility is designed to study new linear acceleration techniques and new radiation sources based on linacs in combination with free electron lasers. The accelerator utilizes a photo-excited, metal cathode, radio frequency electron gun followed by two travelling wave accelerating sections and an Experimental Hall for the study program. (Author) 5 refs., 4 figs., tab

  7. Operation of the Brookhaven National Laboratory Accelerator Test Facility

    Early operation of the 50 MeV high brightness electron linac of the Accelerator Test Facility is described along with experimental data. This facility is designed to study new linear acceleration techniques and new radiation sources based on linacs in combination with free electron lasers. The accelerator utilizes a photo-excited, metal cathode, radio frequency electron gun followed by two travelling wave accelerating sections and an Experimental Hall for the study program

  8. Accelerated aging of catalytically airblown asphalt membranes under simulated uranium mill tailings impoundment conditions

    This paper evaluates the performance of asphalt membranes by examining the chemical and permeability changes experienced by the asphalt during aging tests. The aging process was accelerated by exposing the asphalt to elevated temperatures, high oxygen concentrations, and increased strengths of aqueous oxidizing agents. The synergistic effects of the variables are evaluated by using a fractional factorial experimental design. The installation costs for a catalytically airblown asphalt liner are roughly half that of the typical polymeric materials, and also less than the rubberized asphalt membrane. The results of the initial accelerated aging tests of the asphalt membranes indicate that this material will provide stable, long-term leachate isolation in a mill tailings environment

  9. Survivability of integrated PVDF film sensors to accelerated ageing conditions in aeronautical/aerospace structures

    This work validates the use of integrated polyvinylidene fluoride (PVDF) film sensors for dynamic testing, even after being subjected to UV-thermo-hygro-mechanical accelerated ageing conditions. The verification of PVDF sensors’ survivability in these environmental conditions, typically confronted by civil and military aircraft, is the main concern of the study. The evaluation of survivability is made by a comparison of dynamic testing results provided by the PVDF patch sensors subjected to an accelerated ageing protocol, and those provided by neutral non-aged sensors (accelerometers). The available measurements are the time-domain response signals issued from a modal analysis procedure, and the corresponding frequency response functions (FRF). These are in turn used to identify the constitutive properties of the samples by extraction of the modal parameters, in particular the natural frequencies. The composite specimens in this study undergo different accelerated ageing processes. After several weeks of experimentation, the samples exhibit a loss of stiffness, represented by a decrease in the elastic moduli down to 10%. Despite the ageing, the integrated PVDF sensors, subjected to the same ageing conditions, are still capable of providing reliable data to carry out a close followup of these changes. This survivability is a determinant asset in order to use integrated PVDF sensors to perform structural health monitoring (SHM) in the future of full-scale composite aeronautical structures. (paper)

  10. Advances in wine aging technologies for enhancing wine quality and accelerating wine aging process.

    Tao, Yang; García, Juan Francisco; Sun, Da-Wen

    2014-01-01

    Wine aging is an important process to produce high-quality wines. Traditionally, wines are aged in oak barrel aging systems. However, due to the disadvantages of the traditional aging technology, such as lengthy time needed, high cost, etc., innovative aging technologies have been developed. These technologies involve aging wines using wood fragments, application of micro-oxygenation, aging on lees, or application of some physical methods. Moreover, wine bottling can be regarded as the second phase of wine aging and is essential for most wines. Each technology can benefit the aging process from different aspects. Traditional oak barrel aging technology is the oldest and widely accepted technology. The application of wood fragments and physical methods are promising in accelerating aging process artificially, while application of micro-oxygenation and lees is reliable to improve wine quality. This paper reviews recent developments of the wine aging technologies. The impacts of operational parameters of each technology on wine quality during aging are analyzed, and comparisons among these aging technologies are made. In addition, several strategies to produce high-quality wines in a short aging period are also proposed. PMID:24345051

  11. Comparison of mice with accelerated aging caused by distinct mechanisms.

    Gurkar, Aditi U; Niedernhofer, Laura J

    2015-08-01

    Aging is the primary risk factor for numerous chronic, debilitating diseases. These diseases impact quality of life of the elderly and consume a large portion of health care costs. The cost of age-related diseases will only increase as the world's population continues to live longer. Thus it would be advantageous to consider aging itself as a therapeutic target, potentially stemming multiple age-related diseases simultaneously. While logical, this is extremely challenging as the molecular mechanisms that drive aging are still unknown. Furthermore, clinical trials to treat aging are impractical. Even in preclinical models, testing interventions to extend healthspan in old age are lengthy and therefore costly. One approach to expedite aging studies is to take advantage of mouse strains that are engineered to age rapidly. These strains are genetically and phenotypically quite diverse. This review aims to offer a comparison of several of these strains to highlight their relative strengths and weaknesses as models of mammalian and more specifically human aging. Additionally, careful identification of commonalities among the strains may lead to the identification of fundamental pathways of aging. PMID:25617508

  12. Experimental evaluation of the Battelle accelerated test design for the solar array at Mead, Nebraska

    Frickland, P.O.; Repar, J.

    1982-04-06

    A previously developed test design for accelerated aging of photovoltaic modules was experimentally evaluated. The studies included a review of relevant field experience, environmental chamber cycling of full-size modules, and electrical and physical evaluation of the effects of accelerated aging during and after the tests. The test results indicated that thermally induced fatigue of the interconnects was the primary mode of module failure as measured by normalized power output. No chemical change in the silicone encapsulant was detectable after 360 test cycles.

  13. Virtual accelerator concept, implementation and preliminary test

    A virtual accelerator is the coupling of a simulation code with the control system of a real machine. 3 operating modes are considered. First, the monitoring mode in which any action on the control system has an impact on both real and virtual machines. This mode allows a direct comparison between simulation results and the real behaviour of the accelerator. Secondly, the flight simulation mode, this mode allows the accelerator operators to simulate the effect of any change in the parameters of the control system before transferring them to the real machine. The main advantage of this mode is to allow the assessment of operating procedures before implementing them on the real machine. The third mode is the automatic steering mode in which the simulation code assumes the reins of the control system of the real machine. This mode allows the making of complex and time-consuming adjustment procedures in an automatic way. TraceWin is a simulation code dedicated to the behaviour of charged-particle beams in a linear accelerator. TraceWin is consistent with the EPICS technology on which the control system of most accelerators is based. A virtual accelerator composed of the SILHI injector combined to the TraceWin code via the EPICS environment has showed its efficiency in the automatic steering mode. (A.C.)

  14. Accelerated lifetime testing of energy storage capacitors used in particle accelerators power converters

    AUTHOR|(SzGeCERN)679542; Genton, Charles-Mathieu

    2015-01-01

    Energy storage capacitors are used in large quantities in high power converters for particle accelerators. In this application capacitors see neither a DC nor an AC voltage but a combination of the two. The paper presents a new power converter explicitly designed to perform accelerated testing on these capacitors and the results of the tests.

  15. Accelerated radiation aging of polymer materials by γ-irradiation in oxygen under pressure

    As an accelerated test of radiation aging of polymer materials at low level radiation environment, the degradation of various polymer materials for electric cable insulation was studied by Co-60 γ-ray irradiation in oxygen under pressure at high dose rate. By this method, the oxidation induced by radiation proceeded throughout the specimens in the same way as at irradiation at low dose rate. The degradation was found to be nearly the same as obtained by the long-term radiation aging at 5 krad/h in air for specially formulated materials. In the combination of radiation-thermal aging, the synergistic effect was remarkable when the sequential aging of radiation oxidation followed by thermal aging was carried out. The tested polymers were polyethylene, ethylene-propylene-diene rubber, chloroprene rubber (Neoprene) and chlorosulfonated polyethylene (Hypalon)

  16. AREAL test facility for advanced accelerator and radiation source concepts

    Tsakanov, V. M.; Amatuni, G. A.; Amirkhanyan, Z. G.; Aslyan, L. V.; Avagyan, V. Sh.; Danielyan, V. A.; Davtyan, H. D.; Dekhtiarov, V. S.; Gevorgyan, K. L.; Ghazaryan, N. G.; Grigoryan, B. A.; Grigoryan, A. H.; Hakobyan, L. S.; Haroutiunian, S. G.; Ivanyan, M. I.; Khachatryan, V. G.; Laziev, E. M.; Manukyan, P. S.; Margaryan, I. N.; Markosyan, T. M.; Martirosyan, N. V.; Mehrabyan, Sh. A.; Mkrtchyan, T. H.; Muradyan, L. Kh.; Nikogosyan, G. H.; Petrosyan, V. H.; Sahakyan, V. V.; Sargsyan, A. A.; Simonyan, A. S.; Toneyan, H. A.; Tsakanian, A. V.; Vardanyan, T. L.; Vardanyan, A. S.; Yeremyan, A. S.; Zakaryan, S. V.; Zanyan, G. S.

    2016-09-01

    Advanced Research Electron Accelerator Laboratory (AREAL) is a 50 MeV electron linear accelerator project with a laser driven RF gun being constructed at the CANDLE Synchrotron Research Institute. In addition to applications in life and materials sciences, the project aims as a test facility for advanced accelerator and radiation source concepts. In this paper, the AREAL RF photoinjector performance, the facility design considerations and its highlights in the fields of free electron laser, the study of new high frequency accelerating structures, the beam microbunching and wakefield acceleration concepts are presented.

  17. Parasite infection accelerates age polyethism in young honey bees.

    Lecocq, Antoine; Jensen, Annette Bruun; Kryger, Per; Nieh, James C

    2016-01-01

    Honey bees (Apis mellifera) are important pollinators and their health is threatened worldwide by persistent exposure to a wide range of factors including pesticides, poor nutrition, and pathogens. Nosema ceranae is a ubiquitous microsporidian associated with high colony mortality. We used lab micro-colonies of honey bees and video analyses to track the effects of N. ceranae infection and exposure on a range of individual and social behaviours in young adult bees. We provide detailed data showing that N. ceranae infection significantly accelerated the age polyethism of young bees, causing them to exhibit behaviours typical of older bees. Bees with high N. ceranae spore counts had significantly increased walking rates and decreased attraction to queen mandibular pheromone. Infected bees also exhibited higher rates of trophallaxis (food exchange), potentially reflecting parasite manipulation to increase colony infection. However, reduction in queen contacts could help bees limit the spread of infection. Such accelerated age polyethism may provide a form of behavioural immunity, particularly if it is elicited by a wide variety of pathogens. PMID:26912310

  18. Degradation of impact fracture during accelerated aging of weld metal on microalloyed steel

    The effect of accelerated aging on the toughness and fracture of the longitudinal weld metal on an API5L-X52 line pipe steel was evaluated by Charpy V-notch impact test, fracture analysis and transmission electron microscopy. Aging was performed at 250 degree centigrade for 100 to 1000 h. The impact results indicated a significant reduction in the fracture energy and impact toughness as a function of aging time, which were achieved by the scanning electron microscope fractography that showed a decrease in the vol fraction of microvoids by Charpy ductile failure with the aging time, which favored the brittle fracture by transgranular cleavage. The minimum vol fraction of microvoids was reached at 500 h due to the peak aged. The microstructural analysis indicated the precipitation of transgranular iron nano carbides in the aged specimens, which was related to the deterioration of toughness and change in the ductile to brittle behavior. (Author) 15 refs

  19. Terrestrial Photovoltaic Module Accelerated Test-To-Failure Protocol

    Osterwald, C. R.

    2008-03-01

    This technical report documents a test-to-failure protocol that may be used to obtain quantitative information about the reliability of photovoltaic modules using accelerated testing in environmental temperature-humidity chambers.

  20. Accelerators for Society - TIARA 2012 Test Infrastructure and Accelerator Research Area (in Polish)

    Romaniuk, R S

    2013-01-01

    TIARA (Test Infrastructure and Accelerator Research Area - Preparatory Phae) is an European Collaboration of Accelerator Technology, which by running research projects, technical, networks and infrastructural has a duty to integrate the research and technical communities and infrastructures in the global scale of Europe. The Collaboration gathers all research centers with large accelerator infrastructures. Other ones, like universities, are affiliated as associate members. TIARA-PP (preparato...

  1. Accelerated Test Method for Corrosion Protective Coatings Project

    Falker, John; Zeitlin, Nancy; Calle, Luz

    2015-01-01

    This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as accurately and reliably as current long-term atmospheric exposure tests. This new accelerated test method will shorten the time needed to evaluate the corrosion protection performance of coatings for NASA's critical ground support structures. Lifetime prediction for spaceport structure coatings has a 5-year qualification cycle using atmospheric exposure. Current accelerated corrosion tests often provide false positives and negatives for coating performance, do not correlate to atmospheric corrosion exposure results, and do not correlate with atmospheric exposure timescales for lifetime prediction.

  2. On the Use of Accelerated Aging Methods for Screening High Temperature Polymeric Composite Materials

    Gates, Thomas S.; Grayson, Michael A.

    1999-01-01

    A rational approach to the problem of accelerated testing of high temperature polymeric composites is discussed. The methods provided are considered tools useful in the screening of new materials systems for long-term application to extreme environments that include elevated temperature, moisture, oxygen, and mechanical load. The need for reproducible mechanisms, indicator properties, and real-time data are outlined as well as the methodologies for specific aging mechanisms.

  3. Accelerated artificial aging of particleboards from residues of CCB treated Pinus sp. and castor oil resin

    Marília da Silva Bertolini; Francisco Antonio Rocco Lahr; Maria Fátima do Nascimento; José Augusto Marcondes Agnelli

    2013-01-01

    Tests simulating exposure to severe weather conditions have been relevant in seeking new applications for particleboard. This study aimed to produce particleboards with residues of CCB (chromium-copper-boron oxides) impregnated Pinus sp. and castor oil-based polyurethane resin, and to evaluate their performance before and after artificial accelerated aging. Panels were produced with different particle mass, resin content and pressing time, resulting eight treatments. Particles moisture and si...

  4. Composites Associated with Pulp-Protection Material: Color-Stability Analysis after Accelerated Artificial Aging

    Cruvinel, Diogo Rodrigues; Garcia, Lucas da Fonseca Roberti; Simonides CONSANI; de Carvalho Panzeri Pires-de-Souza, Fernanda

    2010-01-01

    Objectives: This study assessed the color stability of two composites associated with two pulp protectors submitted to accelerated artificial aging (AAA). Methods: 60 test specimens were made with 0.5 mm of protection material (calcium hydroxide - CH or glass ionomer cement - GIC) and 2.5 mm of restoration material (Concept or QuixFil) and divided into 3 groups (n=10) according to the type of protection material/composite, and the control group (no protection). After polishing, color readings...

  5. The electron test accelerator safety in design and operation

    The Electron Test Accelerator is being designed as an experiment in accelerator physics and technology. With an electron beam power of up to 200 kW the operation of the accelerator presents a severe radiation hazard as well as rf and electrical hazards. The design of the safety system provides fail-safe protection while permitting flexibility in the mode of operation and minimizing administrative controls. (auth)

  6. Beam acceleration test of the HIMAC injector

    A heavy-ion synchrotron dedicated to medical use is under construction at National Institute of Radiological Sciences. The injector system, comprising a PIG source, an ECR source, an RFQ linac, and an Alvarez linac of 100MHz, accelerates heavy ions with a charge-to-mass ratio as small as 1/7, up to 6 MeV/u. First operation of the injector system has shown satisfactory performance. (author)

  7. Timescale Correlation between Marine Atmospheric Exposure and Accelerated Corrosion Testing

    Montgomery, Eliza L.; Calle, Luz Marina; Curran, Jerone C.; Kolody, Mark R.

    2011-01-01

    Evaluation of metal-based structures has long relied on atmospheric exposure test sites to determine corrosion resistance in marine environments. Traditional accelerated corrosion testing relies on mimicking the exposure conditions, often incorporating salt spray and ultraviolet (UV) radiation, and exposing the metal to continuous or cyclic conditions of the corrosive environment. Their success for correlation to atmospheric exposure is often a concern when determining the timescale to which the accelerated tests can be related. Accelerated laboratory testing, which often focuses on the electrochemical reactions that occur during corrosion conditions, has yet to be universally accepted as a useful tool in predicting the long term service life of a metal despite its ability to rapidly induce corrosion. Although visual and mass loss methods of evaluating corrosion are the standard and their use is imperative, a method that correlates timescales from atmospheric exposure to accelerated testing would be very valuable. This work uses surface chemistry to interpret the chemical changes occurring on low carbon steel during atmospheric and accelerated corrosion conditions with the objective of finding a correlation between its accelerated and long-term corrosion performance. The current results of correlating data from marine atmospheric exposure conditions at the Kennedy Space Center beachside corrosion test site, alternating seawater spray, and immersion in typical electrochemical laboratory conditions, will be presented. Key words: atmospheric exposure, accelerated corrosion testing, alternating seawater spray, marine, correlation, seawater, carbon steel, long-term corrosion performance prediction, X-ray photoelectron spectroscopy.

  8. Accelerators for Society - TIARA 2012 Test Infrastructure and Accelerator Research Area (in Polish)

    Romaniuk, R S

    2013-01-01

    TIARA (Test Infrastructure and Accelerator Research Area - Preparatory Phae) is an European Collaboration of Accelerator Technology, which by running research projects, technical, networks and infrastructural has a duty to integrate the research and technical communities and infrastructures in the global scale of Europe. The Collaboration gathers all research centers with large accelerator infrastructures. Other ones, like universities, are affiliated as associate members. TIARA-PP (preparatory phase) is an European infrastructural project run by this Consortium and realized inside EU-FP7. The paper presents a general overview of TIARA activities, with an introduction containing a portrait of contemporary accelerator technology and a digest of its applications in modern society.

  9. Envelhecimento acelerado em sementes de trigo Accelerated aging in wheat seeds

    Daniele Cardoso Pedroso

    2010-11-01

    Full Text Available O presente trabalho teve o objetivo de estudar procedimentos de condução do teste de envelhecimento acelerado para determinar o potencial fisiológico de sementes de trigo. Utilizaram-se quatro cultivares: 'Pampeano', 'Safira', 'Ônix' e 'Jaspe'. Foram realizadas determinações de teor de água e avaliações de germinação, emergência, índice de velocidade de emergência e teste de envelhecimento acelerado. O teste de envelhecimento acelerado foi conduzido de três formas: teste tradicional (água, teste com solução saturada de NaCl (11g de NaCl por 100mL de água e teste com solução supersaturada de NaCl (40g de NaCl por 100mL de água, nos períodos de 48, 72 e 96h de permanência na câmara de envelhecimento a 42°C. O teste de envelhecimento acelerado com solução saturada de NaCl, no período de 96h, foi o mais adequado para avaliar o potencial fisiológico das sementes de trigo, em alto, médio e baixo vigor.This research aimed to study procedures for conducting the accelerated aging test to determine the physiological potential of wheat seeds. The experiment was conducted with four varieties: 'Pampeano', 'Sapphire', Onyx' and 'Jasper'. Tests were performed with water content, germination, seedling emergence, speed of emergence and accelerated aging. The accelerated aging test was conducted in three stages: traditional (water, test using saturated NaCl solution (11g of NaCl per 100mL of water and with the use of supersaturated solution of NaCl (40g of NaCl per 100mL of water, each for 48, 72 and 96h at 42°C. The accelerated aging test with saturated solution of NaCl, within 96h was suitable to evaluate the physiological potential of seeds of wheat in high, medium and low vigor.

  10. ACCELERATED AGEING EFFECTS ON CURCUBITEA PEPO SEED OIL

    D. Mampouya A. H. W. Nakavoua

    2013-06-01

    Full Text Available Accelerated ageing of curcubitea pepo seed oil was followed by simulation of UV (light and ambiant oxygen actions held separately then simultaneously in order to know the effects of these parameters on this oil resistance to deterioraton. Nine withdrawals had undergone analyses by titrimetry supported by spectroscopic analyses notably MIR (Medium Infrared, DSC (Differential Scanning Calorimetry and also a gas chromatography for the composition in FA. This study has showed that pumpkin seed oil displays a weak resistance to UV which results among other in a decrease of unsaponifiable compounds. Its oxidization takes place very quickly in the presence of ambiant oxygen. However the accumulated action of the two factors weakens to the highest degree pumpkin seed oil and this results in polymerization. It has also enabled us to show the link between the formation of recticulations in the oil matrix and variations at the level of the molecular structure of pumpkin seed oil.

  11. Accelerated Aging System for Prognostics of Power Semiconductor Devices

    Celaya, Jose R.; Vashchenko, Vladislav; Wysocki, Philip; Saha, Sankalita

    2010-01-01

    Prognostics is an engineering discipline that focuses on estimation of the health state of a component and the prediction of its remaining useful life (RUL) before failure. Health state estimation is based on actual conditions and it is fundamental for the prediction of RUL under anticipated future usage. Failure of electronic devices is of great concern as future aircraft will see an increase of electronics to drive and control safety-critical equipment throughout the aircraft. Therefore, development of prognostics solutions for electronics is of key importance. This paper presents an accelerated aging system for gate-controlled power transistors. This system allows for the understanding of the effects of failure mechanisms, and the identification of leading indicators of failure which are essential in the development of physics-based degradation models and RUL prediction. In particular, this system isolates electrical overstress from thermal overstress. Also, this system allows for a precise control of internal temperatures, enabling the exploration of intrinsic failure mechanisms not related to the device packaging. By controlling the temperature within safe operation levels of the device, accelerated aging is induced by electrical overstress only, avoiding the generation of thermal cycles. The temperature is controlled by active thermal-electric units. Several electrical and thermal signals are measured in-situ and recorded for further analysis in the identification of leading indicators of failures. This system, therefore, provides a unique capability in the exploration of different failure mechanisms and the identification of precursors of failure that can be used to provide a health management solution for electronic devices.

  12. Does cyclic stress and accelerated ageing influence the wear behavior of highly crosslinked polyethylene?

    Affatato, Saverio; De Mattia, Jonathan Salvatore; Bracco, Pierangiola; Pavoni, Eleonora; Taddei, Paola

    2016-06-01

    First-generation (irradiated and remelted or annealed) and second-generation (irradiated and vitamin E blended or doped) highly crosslinked polyethylenes were introduced in the last decade to solve the problems of wear and osteolysis. In this study, the influence of the Vitamin-E addition on crosslinked polyethylene (XLPE_VE) was evaluated by comparing the in vitro wear behavior of crosslinked polyethylene (XLPE) versus Vitamin-E blended polyethylene XLPE and conventional ultra-high molecular weight polyethylene (STD_PE) acetabular cups, after accelerated ageing according to ASTM F2003-02 (70.0±0.1°C, pure oxygen at 5bar for 14 days). The test was performed using a hip joint simulator run for two millions cycles, under bovine calf serum as lubricant. Mass loss was found to decrease along the series XLPE_VE>STD_PE>XLPE, although no statistically significant differences were found between the mass losses of the three sets of cups. Micro-Raman spectroscopy was used to investigate at a molecular level the morphology changes induced by wear. The spectroscopic analyses showed that the accelerated ageing determined different wear mechanisms and molecular rearrangements during testing with regards to the changes in both the chain orientation and the distribution of the all-trans sequences within the orthorhombic, amorphous and third phases. The results of the present study showed that the addition of vitamin E was not effective to improve the gravimetric wear of PE after accelerated ageing. However, from a molecular point of view, the XLPE_VE acetabular cups tested after accelerated ageing appeared definitely less damaged than the STD_PE ones and comparable to XLPE samples. PMID:26970299

  13. Preliminary power test on C-band accelerator

    A C-band 2 MeV standing wave accelerator is under development for engineering research on accelerator miniaturization. At present, significant progress has been achieved. The accelerating tube has been fully sealed, and the hot test platform for the accelerator has been built. At the repetition rate of 50 Hz, preliminary power test has been performed. It used the ionization chamber dose monitor to test the dose rate of X-rays at 1 m before the target, and the steel absorption method to test the energy of the electron beam. The preliminary test results show that, the beam energy is about 2.5 MeV, and the dose rate can be over 330 mGy/(min · m). (authors)

  14. Aging test results of an asphalt membrane liner

    The objective of the asphalt aging study described in this report was to determine the expected performance lifetime of a catalytically airblown asphalt membrane as a seepage barrier for inactive uranium mill tailings. The study, conducted by Pacific Northwest Laboratory for the Department of Energy's Uranium Mill Tailings Remedial Action Program, showed through chemical compatibility tests that the asphalt membrane is well suited for this purpose. The chemical compatibility tests were designed to accelerate the aging reactions in the asphalt and to determine the accelerated aging effect. Higher temperatures and oxygen concentrations proved to be effective acceleration parameters. By infrared spectral analysis, the asphalt was determined to have undergone 7 years of equivalent aging in a 3-month period when exposed to 400C and 1.7 atm oxygen pressure. However, the extent of aging was limited to a maximum penetration of 0.5% of the total liner thickness. It was concluded that the liner could be expected to be effective as a seepage barrier for at least 1000 years before the entire thickness of the liner would be degraded

  15. Accelerated thermal aging of petroleum-based ferrofluids

    Segal, V.; Nattrass, D.; Raj, K.; Leonard, D.

    1999-07-01

    The effect of elevated temperature on the physical and insulating properties of ferrofluid specifically developed for use as a liquid dielectric (D-fluid) for power transformers has been investigated. The D-fluid was produced as a colloidal mix of a specifically synthesized ferrofluid with a conventional mineral oil, and it was subjected to thermal aging conditions modeled after a typical power transformer where the insulation fluid is expected to retain its dielectric performance for about 40 years of continuous service in a sealed tank. The well-known Arrhenius relationship was employed to model "life in service" for up to 40 years at 105°C which corresponded to holding the samples in sealed jars for 10 weeks at 185°C. Another set of small ampules (5 ml) was prepared to test the main physical properties after even longer aging. D-fluid tested after a period of 34 and 50 weeks at 185°C showed no degradation of thermal or colloid stability. The dielectric colloid was also subjected to a 21 day-long test at 110°C in a sealed jar in the presence of typical transformer materials: copper, cellulose, and silicon steel (so-called "bomb" test). Finally, the ferrofluid went through an oxidation stability test (ASTM D2440). Test results show that the newly developed dielectric colloid satisfies the long-term service requirements the transformer users typically apply to conventional mineral oils.

  16. [Anti-aging studies on the senescence accelerated mouse (SAM) strains].

    Takahashi, Ryoya

    2010-01-01

    Senescence accelerated mouse (SAM), a murine model of accelerated senescence, was established by Toshio Takeda and colleagues. SAM consists of series of SAMP (prone) and SAMR (resistant) lines. All SAMP lines (from SAMP1 to SAMP11) are characterized by accelerated accumulation of senile features, earlier onset and faster progress of age-associated pathological phenotypes, such as amyloidosis, impaired immune response, senile osteoporosis and deficits in learning and memory. These SAMP lines are useful for evaluation of putative anti-aging therapies. For example, SAMP1 line is used to study the anti-aging effect of the antioxidant containing foods and various anti-oxidants, such as coenzyme Q10, vitamin C, lycopene. SAMP8 line exhibiting an early onset of impaired learning and memory is often used for test strategies for therapeutic intervention of dementia of early onset. SAMP6 is used as an animal model for developing new strategies for the treatment of osteoporosis in humans. Various lines of SAM (P1, P6, P8, P10 and R1) are now commercially available for research. In this review, I will briefly introduce various usages of SAM in anti-aging research. PMID:20046059

  17. Scientists confirm delay in testing new CERN particle accelerator

    2007-01-01

    "Scientists seeking to uncover the secrets of the universe will have to wait a little longer after the CERN laboratory inswitzerland on Monday confirmed a delay in tests of a massive new particle accelerator." (1 page)

  18. Accelerated aging methods of electrical equipment at Electricite de France

    The nuclear safety requirements for class IE electrical equipment imply the simulation of natural aging in qualification test programs. Such requirements quite agree with E.D.F. practice of qualification tests in order to show aptitude to long-life service of conventional equipment for electrical generation and supply. Such procedures, whose elaboration needs sometimes up to five years, have now the benefit of enough experience to appreciate their effectiveness. From another standpoint, class IE equipment is often identical or similar to conventional equipment. For these reasons, E.D.F. tended towards the use of its conventional aging procedures or of similar ones. Such procedures are actually used for equipment that does not have to function during a loss-of-coolant accident (LOCA) or main steam link break (MSLB)

  19. Reproducing ten years of road ageing - Accelerated carbonation and leaching of EAF steel slag

    Reuse of industrial aggregates is still hindered by concern for their long-term properties. This paper proposes a laboratory method for accelerated ageing of steel slag, to predict environmental and technical properties, starting from fresh slag. Ageing processes in a 10-year old asphalt road with steel slag of electric arc furnace (EAF) type in the subbase were identified by scanning electron microscopy (SEM) and leaching tests. Samples from the road centre and the pavement edge were compared with each other and with samples of fresh slag. It was found that slag from the pavement edge showed traces of carbonation and leaching processes, whereas the road centre material was nearly identical to fresh slag, in spite of an accessible particle structure. Batches of moisturized road centre material exposed to oxygen, nitrogen or carbon dioxide (CO2) were used for accelerated ageing. Time (7-14 days), temperature (20-40 oC) and initial slag moisture content (8-20%) were varied to achieve the carbonation (decrease in pH) and leaching that was observed in the pavement edge material. After ageing, water was added to assess leaching of metals and macroelements. 12% moisture, CO2 and seven days at 40 oC gave the lowest pH value. This also reproduced the observed ageing effect for Ca, Cu, Ba, Fe, Mn, Pb, Ca (decreased leaching) and for V, Si, and Al (increased leaching). However, ageing effects on SO4, DOC and Cr were not reproduced.

  20. Accelerated aging of melon seeds Envelhecimento acelerado em sementes de melão

    Salvador Barros Torres

    2003-02-01

    Full Text Available Accelerated aging is one of the most useful tests used for the evaluation of seed vigor but it is seldomly used to test melon (Cucumis melo L. seeds. The objective this research was to compare different procedures of the accelerated aging test to evaluate the physiological quality of melon seeds and the efficiency of using saturated salt solution for the control of water uptake by seeds. Five seed lots each of the hybrids AF-646 and AF-682 were tested for germination, seedling emergence, traditional accelerated aging (periods 0f 48, 72 and 96 hours, at 38 or 41°C and salt saturated accelerated aging. The accelerated aging test (traditional procedure and with salt solution for 72h and 96h, at 38 or 41°C was sensitive to detect differences in the physiological quality of the seeds. It was also observed that the seed water content after salt saturated accelerated aging was lower and more uniform, thus presenting advantagens in relation to the traditional procedure.O teste de envelhecimento acelerado é um dos mais utilizados para a avaliação do potencial fisiológico das sementes de várias espécies. Entretanto, estudos com sementes de melão ainda são escassos. Avaliou-se procedimentos para a condução do teste de envelhecimento acelerado para avaliação do potencial fisiológico de sementes de melão (Cucumis melo L., incluindo o uso de solução saturada de sal em substituição à água. Cinco lotes de sementes, dos híbridos AF-646 e AF-682, foram submetidos aos testes de germinação, emergência de plântulas em casa de vegetação e envelhecimento acelerado (períodos de 48, 72 ou 96 horas, a 38 ou 41°C, com e sem o uso de solução saturada de NaCl. O teste de envelhecimento acelerado (procedimento tradicional e com solução salina, conduzido com períodos de exposição de 72h e 96h a 38 ou 41°C, apresentou sensibilidade suficiente para detectar diferenças no potencial fisiológico de lotes de sementes de melão. A utiliza

  1. Testing of electric motors for monitoring age-related degradations

    A 10-hp industrial motor with 12 yr of service in a commercial nuclear power plant and a 400-hp failed motor with > 20 yr of service life in a nuclear research facility were tested. The 10-hp motor was subjected to plug reverse cycling to induce accelerated aging while various insulation and bearing test parameters were monitored. Stator coils from the 400-hp motor were tested to diagnose age-related deterioration of insulation dielectric properties. The test objectives were to identify cost-effective motor testing methods or functional indicators that provide adequate feedback to detect degradation in motor components. It was found that monitoring and testing methods are available to detect degradation at an incipient stage

  2. Development of a new accelerated salt crystallization test

    Wijffels, T.J.; Lubelli, B.A.

    2006-01-01

    TNO Built Environment and Geosciences has developed, in cooperation with other institutes in the European project Compass1, a new accelerated salt crystallization test. In this paper the design process leading to the definition of this test is described. Preliminary tests studying the influence of t

  3. Testing of high-vacuum pumps for charged particle accelerators

    To study a possibility of employing different types of pumps in charged-particle accelerators the following pumps have been tested: electric-arc, turbomolecular and cryogenic. The research has been carried out on a test bench which made it possible to determine the pumping-out rate for different gases (constant-volume methods), measure their limiting pressure and study the spectra of different gases by using mass spectrometers. It was possible also to warm up the pumps and pumped-out volumes. From these tests it was concluded that: (1) the electric-arc pump does not meet the accelerator pumping-out requirements; (2) the turbomolecular pump with a nitrogen-sorption trap can be recommended for pumping-out accelerators but requires modification of the supply unit; (3) the cryogenic pump can be recommended for pumpimg-out of accelerators but requires modification of the automatic system for replenishment of the cryogenic fluid

  4. Recent progress of the advanced test accelerator

    Prono, D.S.

    1985-05-13

    Attempts to further improve the beam brightness from field emission cathodes are currently centered on the issue of how beam optics and phase mixing within the injector transport tend to ''average down'' the beam brightness. Particle simulation work indicates that beam brightness can be significantly improved by simply reducing the injector transport magnetic field and losing peak transport current, i.e., only transporting that high brightness portion of the total current. The simulation results shown in Figure 8 suggest that beam brightness can be increased perhaps a factor of 5 or more simply by ''tuning for brightness'' rather than tuning for peak transported current. If this can indeed be experimentally realized and the resulting beam matched onto accelerator transport (magnetic and/or laser guided) without emittance degradation then simple field emission cathodes would, at least in the immediately near term, saisfy the needs for 10 micron FEL experiments. 8 refs., 8 figs.

  5. Study on radiation sickness and aging using the senescense accelerated mouse

    We compared several statistical methods for dealing with the results from the step-down passive avoidance test using the senescense accelerated mouse, which is recently used to investigate aging. Testing the difference of step-down latency between the irradiated group and control group, we often obtained conflicting results from different statistical methods. Step-down latency does not obey a normal distribution, and includes censoring observations. Therefore, the log rank test, which is usually regarded as one of the statistical methods for life time analysis, seems more suitable than t-test or Wilcoxon's rank-sum test for comparing step-down latency. Namely, the log rank test treats cases which step down within 180 seconds as failures and cases which do not step down within 180 seconds as censored cases. (author)

  6. Effect of disinfection and accelerated ageing on dimensional stability and detail reproduction of a facial silicone with nanoparticles.

    Pesqueira, A A; Goiato, M C; Dos Santos, D M; Haddad, M F; Moreno, A

    2012-05-01

    The aim of the present study was to evaluate the effect of disinfection and accelerated ageing on the dimensional stability and detail reproduction of a facial silicone with different types of nanoparticle. A total of 60 specimens were fabricated with Silastic MDX 4-4210 silicone and they were divided into three groups: colourless and pigmented with nanoparticles (make-up powder and ceramic powder). Half of the specimens of each group were disinfected with Efferdent tablets and half with neutral soap for 60 days. Afterwards, all specimens were subjected to accelerated ageing. Both dimensional stability and detail reproduction tests were performed after specimen fabrication (initial period), after chemical disinfection, and after accelerated ageing periods (252, 504 and 1008 hours). The dimensional stability test was conducted using AutoCAD software, while detail reproduction was analysed using a stereoscope magnifying glass. Dimensional stability values were statistically evaluated by analysis of variance (ANOVA) followed by Tukey's test (p < 0.01). Detail reproduction results were compared using a score. Chemical disinfection and also accelerated ageing affected the dimensional stability of the facial silicone with statistically significant results. The silicone's detail reproduction was not affected by these two factors regardless of nanoparticle type, disinfection and accelerated ageing. PMID:22428808

  7. Impact absorption of four processed soft denture liners as influenced by accelerated aging.

    Kawano, F; Koran, A; Nuryanti, A; Inoue, S

    1997-01-01

    The cushioning effect of soft denture liners was evaluated by using a free drop test with an accelerometer. Materials tested included SuperSoft (Coe Laboratories, Chicago, IL), Kurepeet-Dough (Kreha Chemical, Tokyo), Molteno Soft (Molten, Hiroshima, Japan), and Molloplast-B (Molloplast Regneri, Karlsruhe, Germany). All materials were found to reduce the impact force when compared to acrylic denture base resin. A 2.4-mm layer of soft denture material demonstrated good impact absorption, and Molloplast-B and Molteno had excellent impact absorption. When the soft denture liner was kept in an accelerated aging chamber for 900 hours, the damping effect recorded increased for all materials tested. Aging of all materials also affected the cushioning effect. PMID:9484071

  8. Statistical analysis of accelerated temperature aging of semiconductor devices

    Johnson, W. A.; Milles, M. F.

    1981-05-01

    A number of semiconductor devices taken from a distribution were operated at several elevated temperatures to induce failure in all devices within a reasonable time. Assuming general characteristics of the device failure probability density function (pdf) and its temperature dependence, the expected cumulative failure function (cff) for devices in normal operation were estimated based on statistical inference, taking the average probability of a random device (from the same distribution but operated at a normal temperature) failing as a function of time. A review of the mathematical formalism employed in semiconductor reliability discussions is included. Three failure pdf's at particular usefulness to this analysis--exponential, normal, and lognormal - are discussed. The cff, at times orders of magnitude loss then, at times comparable to the desired system useful, life (*10 to the 4th power to 10 to the 5th power hr) is considered. A review of accelerated temperature aging is presented, and the assumption concerning the general characteristics of the failure pdf, which are fundamental to this analysis, are emphasized.

  9. Acceleration of the LHC commissioning tests

    2008-01-01

    The quadrupole and main dipole circuits have been powered up to 10,200 amps in Sector 4-5. Sector 5-6 is currently being cooled and will be the next to undergo electrical tests, which will be stepped up over the next few weeks.

  10. Electrical performance characteristics of the SSC Accelerator System String Test

    The intent of the Accelerator System String Test (ASST) is to obtain data for model verification and information on the magnitudes of pressures and voltages encountered in an accelerator environment. The ASST milestone run was achieved during July and August, 1992 and consisted of demonstrating the accelerator components could be configured together as a system operating at full current. Following the milestone run, the string was warmed to counteract some design flaws that impeded the operational range. The string was again cooled to cryogenic temperatures in October, and a comprehensive power testing program was conducted through the end of January, 1993. This paper describes how the collider arc components operate in an accelerator environment during quenches induced by firing both strip heaters and spot heaters. Evaluation of the data illustrates how variations in the design parameters on magnets used in a string environment can impact system performance

  11. Electrical performance characteristics of the SSC accelerator system string test

    The intent of the Accelerator System String Test (ASST) is to obtain data for model verification and information on the magnitudes of pressures and voltages encountered in an accelerator environment. The ASST milestone run was achieved during July and August, 1992 and consisted of demonstrating that the accelerator components could be configured together as a system operating at full current. Following the milestone run, the string was warmed to counteract some design flaws that impeded the operational range. The string was again cooled to cryogenic temperatures in October, and a comprehensive power testing program was conducted through the end of January, 1993. This paper describes how the collider arc components operate in an accelerator environment during quenches induced by firing both strip heaters and spot heaters. Evaluation of the data illustrates how variations in the design parameters on magnets used in a string environment can impact system performance

  12. The Next Linear Collider test accelerator: Status and results

    At SLAC, the authors are pursuing the design of a Next Linear Collider (NLC) which would begin with a center-of-mass energy of 0.5 TeV, and would be upgradable to 1.0 TeV and beyond. To achieve this high energy, for the past several years they have been working on the development of a high-gradient 11.4-GHz (X-band) linear accelerator for the main linac of the collider. In this paper, they present the status and initial results from the ''Next Linear Collider Test Accelerator'' (NLCTA). The goal of the NLCTA is to model the high gradient linac of the NLC. It incorporates the new technologies of X-band accelerator structures, rf pulse compression systems and high-power klystrons into a 0.5 to 1.0 GeV linac which is a test bed for beam dynamics issues related to high-gradient acceleration

  13. A comparative study of accelerated tests to simulate atmospheric corrosion

    In this study, specimens coated with five organic coating systems were exposed to accelerated tests for periods up to 2000 hours, and also to weathering for two years and six months. The accelerated tests consisted of the salt spray test, according to ASTM B-117; Prohesion (ASTM G 85-98 annex 5A); Prohesion combined with cyclic exposure to UV-A radiation and condensation; 'Prohchuva' a test described by ASTM G 85-98 using a salt spray with composition that simulated the acid rain of Sao Paulo, but one thousand times more concentrated, and 'Prohchuva' combined with cyclic exposure to UV-A radiation and condensation. The coated specimens were exposed with and without incision to expose the substrate. The onset and progress of corrosion at and of the exposed metallic surface, besides coating degradation, were followed by visual observation, and photographs were taken. The coating systems were classified according to the extent of corrosion protection given to the substrate, using a method based on ASTM standards D-610, D-714, D-1654 and D-3359. The rankings of the coatings obtained from accelerated tests and weathering were compared and contrasted with classification of the same systems obtained from literature, for specimens exposed to an industrial atmosphere. Coating degradation was strongly dependent on the test, and could be attributed to differences in test conditions. The best correlation between accelerated test and weathering was found for the test Prohesion alternated with cycles of exposure to UV-A radiation and condensation. (author)

  14. The Advanced Superconducting Test Accelerator at Fermilab: Science Program

    Piot, Philippe [Fermilab; Harms, Elvin [Fermilab; Henderson, Stuart [Fermilab; Leibfritz, Jerry [Fermilab; Nagaitsev, Sergei [Fermilab; Shiltsev, Vladimir [Fermilab; Valishev, Alexander [Fermilab

    2014-07-01

    The Advanced Superconducting Test Accelerator (ASTA) currently in commissioning phase at Fermilab is foreseen to support a broad range of beam-based experiments to study fundamental limitations to beam intensity and to develop novel approaches to particle-beam generation, acceleration and manipulation. ASTA incorporates a superconducting radiofrequency (SCRF) linac coupled to a flexible high-brightness photoinjector. The facility also includes a small-circumference storage ring capable of storing electrons or protons. This report summarizes the facility capabilities, and provide an overview of the accelerator-science researches to be enabled.

  15. Evaluation of Experimental Parameters in the Accelerated Aging of Closed-Cell Foam Insulation

    Stovall, Therese K [ORNL; Vanderlan, Michael [ORNL; Atchley, Jerald Allen [ORNL

    2012-12-01

    The thermal conductivity of many closed-cell foam insulation products changes over time as production gases diffuse out of the cell matrix and atmospheric gases diffuse into the cells. Thin slicing has been shown to be an effective means of accelerating this process in such a way as to produce meaningful results. Efforts to produce a more prescriptive version of the ASTM C1303 standard test method led to the ruggedness test described here. This test program included the aging of full size insulation specimens for time periods of five years for direct comparison to the predicted results. Experimental parameters under investigation include: slice thickness, slice origin (at the surface or from the core of the slab), thin slice stack composition, product facings, original product thickness, product density, and product type. The test protocol has been completed and this report provides a detailed evaluation of the impact of the test parameters on the accuracy of the 5-year thermal conductivity prediction.

  16. Testing General Relativity With Laser Accelerated Electron Beams

    Gergely, L. Á.; Harko, T.

    2012-01-01

    Electron accelerations of the order of $10^{21} g$ obtained by laser fields open up the possibility of experimentally testing one of the cornerstones of general relativity, the weak equivalence principle, which states that the local effects of a gravitational field are indistinguishable from those sensed by a properly accelerated observer in flat space-time. We illustrate how this can be done by solving the Einstein equations in vacuum and integrating the geodesic equations of motion for a un...

  17. The Accelerated Test of Chloride Permeability of Concrete

    TAN Ke-feng; ODD E Gjφrv

    2003-01-01

    The availability of accelerated chloride permeability test and the effect of w/c ratio, incorporation of silica fume, maximum aggregate size and aggregate type on the chloride permeability were studied. The mathematic analysis certifies that there is a linear relationship between accelerated test and natural diffusion. Test results show that the chloride permeability of concrete increases as w/c ratio increases whilst a limited amount of replacement of cement with silica fume, the chloride permeability decreases dramatically. The maximum aggregate size in the range of 8 to 25 mm seems also affect chloride permeability but with a much less significant level. The chloride permeability of silica fume lightweight aggregate concrete is very low, especially the concrete made with dry lightweight concrete. The chloride permeability can be evaluated by this accelerated test method.

  18. Nuclear-waste-package materials degradation modes and accelerated testing

    This report reviews the materials degradation modes that may affect the long-term behavior of waste packages for the containment of nuclear waste. It recommends an approach to accelerated testing that can lead to the qualification of waste package materials in specific repository environments in times that are short relative to the time period over which the waste package is expected to provide containment. This report is not a testing plan but rather discusses the direction for research that might be considered in developing plans for accelerated testing of waste package materials and waste forms

  19. Evaluation of an Accelerated ELDRS Test Using Molecular Hydrogen

    Pease, Ronald L.; Adell, Philippe C.; Rax, Bernard; McClure, Steven; Barnaby, Hugh J.; Kruckmeyer, Kirby; Triggs, B.

    2011-01-01

    An accelerated total ionizing dose (TID) hardness assurance test for enhanced low dose rate sensitive (ELDRS) bipolar linear circuits, using high dose rate tests on parts that have been exposed to molecular hydrogen, has been proposed and demonstrated on several ELDRS part types. In this study several radiation-hardened "ELDRS-free" part types have been tested using this same approach to see if the test is overly conservative.

  20. 车用三元催化转化器快速老化试验研究%Accelerated Aging Tests of Three-way Catalytic Convener on Automotive

    郝宝玉; 侯献军; 彭辅明; 刘华刚; 颜伏伍

    2011-01-01

    根据国内外三元催化转化器老化评价方法,建立了车用催化器快速老化试验装置,并对试验装置进行优化.试验数据表明,三元催化转化器经过100 h老化后CO、HC、NOx的起燃温度分别升高42℃、40℃、30℃,对催化器起燃不利,HC的转化效率显著降低,催化器老化后空燃比特性曲线的高效窗口几乎不复存在,催化器性能趋向恶化.%Based on experiences of auto catalytic converter evaluation method, automotive catalytic converter rapid aging test e-quipment was developed and optimized. Experimental data show that,after three-way catalytic converter being aged,the ignition temperature of CO, HC, Nox, respectively increased by 42℃ ,40℃ ,30℃. The ignition temperature increase performed negative effects on the catalytic converter, and HC significantly reduced the conversion efficiency of catalytic device. The efficient window of air -fuel ratio curve had almost disappeared after catalytic converter aged,and catalyst performance deteriorated.

  1. Fine-pore aeration diffusers: accelerated membrane ageing studies.

    Kaliman, An; Rosso, Diego; Leu, Shao-Yuan; Stenstrom, Michael K

    2008-01-01

    Polymeric membranes are widely used in aeration systems for biological treatment. These membranes may degrade over time and are sensitive to fouling and scaling. Membrane degradation is reflected in a decline in operating performance and higher headloss, resulting in increased energy costs. Mechanical property parameters, such as membrane hardness, Young's modulus, and orifice creep, were used to characterize the performance of membranes over time in operation and to predict their failure. Used diffusers from municipal wastewater treatment plants were collected and tested for efficiency and headloss, and then dissected to facilitate measurements of Young's modulus, hardness, and orifice creep. Higher degree of membrane fouling corresponded consistently with larger orifice creep. A lab-scale membrane ageing simulation was performed with polyurethane and four different ethylene-propylene-diene (EPDM) membrane diffusers by subjecting them to chemical ageing cycles and periodic testing. The results confirmed full-scale plant results and showed the superiority of orifice creep over Young's modulus and hardness in predicting diffuser deterioration. PMID:17706264

  2. Lifetime stress accelerates epigenetic aging in an urban, African American cohort: relevance of glucocorticoid signaling

    Zannas, A.; Arloth, J.; Carrillo Roa, T.; Iurato, S.; Roeh, S.; Ressler, K; Nemeroff, C.; Smith, A.; Bradley, B; Heim, C; Menke, A.; Lange, J; Brueckl, T.; Ising, M; Wray, N.

    2015-01-01

    Background Chronic psychological stress is associated with accelerated aging and increased risk for aging-related diseases, but the underlying molecular mechanisms are unclear. Results We examined the effect of lifetime stressors on a DNA methylation-based age predictor, epigenetic clock. After controlling for blood cell-type composition and lifestyle parameters, cumulative lifetime stress, but not childhood maltreatment or current stress alone, predicted accelerated epigenetic aging in an ur...

  3. Protective role of female gender in programmed accelerated renal aging in the rat

    Pijacka, Wioletta; Clifford, Bethan; Tilburgs, Chantal; Joles, Jaap A.; Langley-Evans, Simon C.; McMullen, Sarah

    2015-01-01

    The aging kidney exhibits a progressive decline in glomerular filtration rate, accompanied by inflammatory and oxidative damage. We hypothesized that accelerated, age-related progression of renal injury is ovarian hormones-dependant. To address this we used an established model of developmentally programmed accelerated renal aging in the rat, superimposed by ovariectomy to assess interactions between ovarian hormones and the aging process. Under our experimental conditions, we found that kidn...

  4. Protective role of female gender in programmed accelerated renal aging in the rat

    Pijacka, Wioletta; Clifford, Bethan; Tilburgs, Chantal; Joles, Jaap A.; Langley-Evans, Simon C.; McMullen, Sarah

    2015-01-01

    The aging kidney exhibits a progressive decline in glomerular filtration rate, accompanied by inflammatory and oxidative damage. We hypothesized that accelerated, age-related progression of renal injury is ovarian hormones-dependant. To address this we used an established model of developmentally programmed accelerated renal aging in the rat, superimposed by ovariectomy to assess interactions between ovarian hormones and the aging process. Under our experimental conditions, we found that kidney...

  5. Hardness evaluation of prosthetic silicones containing opacifiers following chemical disinfection and accelerated aging

    Marcelo Coelho Goiato

    2010-09-01

    Full Text Available We evaluated the effects of disinfection and aging on the hardness of silicones containing opacifiers and intended for use in facial prosthetics. A total of 90 samples were produced using a cylindrical metal mold 3 mm in height and 30 mm in diameter. The samples were fabricated from Silastic MDX 4-4210 silicone in three groups: GI contained no opacifier, GII contained barium sulfate (Ba, and GIII contained titanium dioxide (Ti. The samples were disinfected using effervescent tablets (Ef, neutral soap (Ns, or 4% chlorhexidine (Cl 3 times a week for 60 days. After this period the samples underwent 1,008 hours of accelerated aging. The hardness was measured using a durometer immediately following the disinfection period and after 252, 504, and 1,008 hours of aging. The data were statistically analyzed using 3-way ANOVA and the Tukey test (p < .05. The GIII group exhibited the greatest variation in hardness regardless of elapsed time. All groups displayed greater hardness after 1,008 hours of accelerated aging independent of disinfectant type. All of the hardness values were within the clinically acceptable range.

  6. Demonstration recommendations for accelerated testing of concrete decontamination methods

    A large number of aging US Department of Energy (DOE) surplus facilities located throughout the US require deactivation, decontamination, and decommissioning. Although several technologies are available commercially for concrete decontamination, emerging technologies with potential to reduce secondary waste and minimize the impact and risk to workers and the environment are needed. In response to these needs, the Accelerated Testing of Concrete Decontamination Methods project team described the nature and extent of contaminated concrete within the DOE complex and identified applicable emerging technologies. Existing information used to describe the nature and extent of contaminated concrete indicates that the most frequently occurring radiological contaminants are 137Cs, 238U (and its daughters), 60Co, 90Sr, and tritium. The total area of radionuclide-contaminated concrete within the DOE complex is estimated to be in the range of 7.9 x 108 ft2or approximately 18,000 acres. Concrete decontamination problems were matched with emerging technologies to recommend demonstrations considered to provide the most benefit to decontamination of concrete within the DOE complex. Emerging technologies with the most potential benefit were biological decontamination, electro-hydraulic scabbling, electrokinetics, and microwave scabbling

  7. Acceleration test of heavy-ion with TIT RFQ linac

    A heavy-ion acceleration system with the TIT-RFQ has been developed. The TIT-RFQ was designed to accelerate particles with a charge to mass ratio ε ≥ 1/16, as it was, the kind of particles was limited because of the insufficient withstanding voltage of the beam injection equipment. In order to solve this problem, the development of the new system was planed, and the work has been carried out since last year. By using this system, the first acceleration of N+ beam was observed in January this year; however, the beam intensity was insufficient. Some problems were pointed out, and the synchronous circuit of a RF pulse was constructed up to now. By using this circuit, the increase of the beam intensity was observed in the second acceleration test in this summer. (author)

  8. Time dependent diffusive shock acceleration and its application to middle aged supernova remnants

    Tang, Xiaping

    2016-01-01

    Recent gamma-ray observations show that middle aged supernova remnants (SNRs) interacting with molecular clouds (MCs) can be sources of both GeV and TeV emission. Based on the MC association, two scenarios have been proposed to explain the observed gamma-ray emission. In one, energetic cosmic ray (CR) particles escape from the SNR and then illuminate nearby MCs, producing gamma-ray emission, while the other involves direct interaction between the SNR and MC. In the direct interaction scenario, re-acceleration of pre-existing CRs in the ambient medium is investigated while particles injected from the thermal pool are neglected in view of the slow shock speeds in middle aged SNRs. However, standard diffusive shock acceleration (DSA) theory produces a steady state particle spectrum that is too flat compared to observations, which suggests that the high energy part of the observed spectrum has not yet reached a steady state. We derive a time dependent DSA solution in the test particle limit for re-acceleration of...

  9. Characterization and Accelerated Ageing of UHMWPE Used in Orthopedic Prosthesis by Peroxide

    Herman Mansur

    2009-05-01

    Full Text Available Ultra-high molecular weight polyethylene (UHMWPE has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important mechanical properties to extend the longevity of knee prostheses. Though accelerated in vitro protocols have been developed to test the relative oxidation resistance of various types of UHMWPE, its mechanism is not accurately understood yet. Thus, in the present study an accelerated ageing of UHMWPE in hydrogen peroxide solution was performed and relative oxidation was extensively characterized by Fourier Transformed Infrared Spectroscopy (FTIR spectroscopy and the morphological changes were analyzed by Scanning Electron Microscopy (SEM. Different chemical groups of UHMWPE associated with the degradation reaction were monitored for over 120 days in order to evaluate the possible oxidation mechanism(s which may have occurred. The results have provided strong evidence that the oxidation mechanism is rather complex, and two stages with their own particular first-order kinetics reaction patterns have been clearly identified. Furthermore, hydrogen peroxide has proven to be an efficient oxidative medium to accelerate ageing of UHMWPE.

  10. Mechanical stability study for Integrable Optics Test Accelerator at Fermilab

    McGee, M. W.; Andrews, R; Carlson, K.; Leibfritz, J.; Nobrega, L.; Valishev, A.

    2016-01-01

    The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p+) diagnostic test ring. A heavy low frequency steel floor girder is proposed as the primary tier for IOTA device component support. Two design lengths; (8) 3.96 m and (2) 3.1 m long girders with identical cross secti...

  11. Automatic testing of medium-frequency acceleration transducers

    An automatic test bench for medium-frequency acceleration transducers employing a method of comparison is described. The following points are discussed: the measurement possibilities of this bench in the frequency range 10Hz-10kHz and for applied acceleration levels of 1000m.s-2 or below; the transducer parameters checked; the uncertainties on the measurement of these parameters. The test procedure is described in detail and illustrated by a concrete case showing the particular form of presentation of the results

  12. High current electron linacs (advanced test accelerator/experimental test accelerator)

    The high current induction accelerator development at the Lawrence Livermore National Laboratory is described. The ATA facility is designed for 10 kA peak currents, 50 nsec pulse lengths and 50 MeV energies. At this time, half of the design current has been accelerated through the entire machine to particle energies of about 45 MeV. Current problem areas and operational experience to date will be discussed. Several key technical areas required development for the ATA machine; this report will survey these developments. The control of transverse beam instabilities required an accelerating cavity design with very low Q. Electron sources capable of 10 kA operation at high rep rates were developed using a plasma sparkboard approach. The pulse power systems on ATA, using the same type of spark gap switches as ETA, have exhibited excellent operational reliability

  13. An accelerated test method for efflorescence in clay bricks

    An investigation into the creation of accelerated efflorescence in clay bricks was undertaken with a view to creating a viable test procedure for determining efflorescence potential. The testing programme incorporated ambient conditions similar to those which promote efflorescence growth in bricks in use. Theoretical investigations into the physical mechanism underlying the creation of efflorescence directed the attempts to accelerate the process. It was found that calcium sulphate efflorescence could not be sufficiently accelerated such that a useful efflorescence test procedure could be proposed. The inability to produce accelerated efflorescence in brick samples was attributed to limitations associated with time dependent salt diffusion in the efflorescence mechanism. The preliminary testing that was undertaken into the creation of efflorescence prompted the use of acid assisted methods to accelerate efflorescence. The acid assisted method that was adopted to provide a possible indication of efflorescence potential relies upon the transformation of low solubility calcium to a more soluble form. The movement of the transformed salt is then induced by cyclic temperature exposure at temperatures similar to those experienced in Spring. The appearance of the transformed calcium salt on the surface of the brick specimen provides an indication of the efflorescence potential. Brick piers constructed on an exposed site and monitored over a 12 month period provided information on the validity of the acid assisted test method. The efflorescence observed on the piers correlated well with that predicted by the acid assisted test, suggesting that the new test has the potential to accurately predict the efflorescence potential of clay bricks Relationships between other properties such as air permeability, sorptivity and tensile strength were investigated such that an alternative method of predicting efflorescence could be achieved. It was found that (within the bounds of the

  14. Quick setup of test unit for accelerator control system

    Testing a single hardware unit of an accelerator control system often requires the setup of a program with graphical user interface. Developing a dedicated application for a specific hardware unit test could be time consuming and the application may become obsolete after the unit tests. This paper documents a methodology for quick design and setup of an interface focused on performing unit tests of accelerator equipment with minimum programming work. The method has three components. The first is a generic accelerator device object (ADO) manager which can be used to setup, store, and log testing controls parameters for any unit testing system. The second involves the design of a TAPE (Tool for Automated Procedure Execution) sequence file that specifies and implements all te testing and control logic. The sting third is the design of a PET (parameter editing tool) page that provides the unit tester with all the necessary control parameters required for testing. This approach has been used for testing the horizontal plane of the Stochastic Cooling Motion Control System at RHIC.

  15. The BNL Accelerator Test Facility and experimental program

    The Accelerator Test Facility (ATF) at BNL is a users' facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high power laser pulses synchronized to the electron beam, suitable for studies of new methods of high gradient acceleration and state of the art free electron lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 to 100 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps Nd:YAG laser and a 100 mJ, 10 ps CO2 laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various acceleration schemes, Free-Electron Laser experiments and a program on the development of high brightness electron beams. The AFT's experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the High power laser will begin operation this year. 28 refs., 4 figs

  16. Experience on high voltage testing and conditioning of accelerator tube for 3 MeV DC accelerator

    In DC Electron Beam Accelerator, accelerating potentials are generated using high voltage multiplier column. Accelerating potentials are uniformly graded to the accelerator tubes for accelerating the electron to attain the required energy. 3 MeV DC Accelerator is in the advance stages of commissioning at Electron Beam Centre Kharghar, Navi Mumbai. It has 10 numbers of accelerating tube each rated for 335 kVdc in 6 kg/cm2 SF6 gas environment outside and vacuum better than 10-7 mbar inside the tube. For safe and reliable operation of the accelerator, all the dynode gaps have to be conditioned and tested for high voltage withstand capability. Accelerating Tube Test Facility (ATTF) was developed for the testing and HV Conditioning of the accelerator tube. Tubes are conditioned with plasma, baking and application of ascending high Voltages. This paper describes the experience on the high voltage conditioning and testing of the accelerator tube of 3 MeV DC Accelerator. The accelerator has been successfully tested at 1 MeV and 10 kW beam power and 1.8 MeV at no load. (author)

  17. Comment on "Testing Planck-Scale Gravity with Accelerators"

    Kalaydzhyan, Tigran

    2016-01-01

    We challenge the analysis and conclusions of the paper Phys. Rev. Lett. 109, 141103 (2012) by V. Gharibyan on the tests of Planck-scale gravity with accelerators. The main objective of the Comment is the observation that the explored domain of "quantum gravity" parameters is already ruled out experimentally from, e.g., absence of the vacuum Cherenkov radiation.

  18. Step-Stress Accelerated Degradation Testing for Solar Reflectors: Preprint

    Jones, W.; Elmore, R.; Lee, J.; Kennedy, C.

    2011-09-01

    To meet the challenge to reduce the cost of electricity generated with concentrating solar power (CSP) new low-cost reflector materials are being developed including metalized polymer reflectors and must be tested and validated against appropriate failure mechanisms. We explore the application of testing methods and statistical inference techniques for quantifying estimates and improving lifetimes of concentrating solar power (CSP) reflectors associated with failure mechanisms initiated by exposure to the ultraviolet (UV) part of the solar spectrum. In general, a suite of durability and reliability tests are available for testing a variety of failure mechanisms where the results of a set are required to understand overall lifetime of a CSP reflector. We will focus on the use of the Ultra-Accelerated Weathering System (UAWS) as a testing device for assessing various degradation patterns attributable to accelerated UV exposure. Depending on number of samples, test conditions, degradation and failure patterns, test results may be used to derive insight into failure mechanisms, associated physical parameters, lifetimes and uncertainties. In the most complicated case warranting advanced planning and statistical inference, step-stress accelerated degradation (SSADT) methods may be applied.

  19. Accelerated ageing of the insect Drosophila melanogaster by γ irradiations of pupae

    The purpose of the study was to induce accelerated aging in the fly Drosophila melanogaster (Diptera) using free radicals, and to distinguish aging from radiation syndrome. After irradiation of 12 to 24-hour-old pupae with doses of 500-2500 rad, very similar fly emergence rates were observed in control and treated populations. The life span was shortened and dose-related in mixed populations and in both virgin and mated male and female populations. Males were more radiosensitive than females. In the 500-2500 rad dose range, all the populations tested were fertile after irradiation. Young treated as pupae and control adults both displayed similar mating ability and negative geotactic responses. Their response levels decreased with time, but the decline was faster and dose-related in the treated animals. The study demonstrates that irradiation of 12 to 24-hour-old pupae with doses of 500-2500 rad induces accelerated aging, without causing serious biological damage. For example, after an irradiation with 1750 rad, the ''lethal time'' (LT) 50 dropped by about 30%. (author)

  20. A Model-based Prognostics Methodology for Electrolytic Capacitors Based on Electrical Overstress Accelerated Aging

    Celaya, Jose; Kulkarni, Chetan; Biswas, Gautam; Saha, Sankalita; Goebel, Kai

    2011-01-01

    A remaining useful life prediction methodology for electrolytic capacitors is presented. This methodology is based on the Kalman filter framework and an empirical degradation model. Electrolytic capacitors are used in several applications ranging from power supplies on critical avionics equipment to power drivers for electro-mechanical actuators. These devices are known for their comparatively low reliability and given their criticality in electronics subsystems they are a good candidate for component level prognostics and health management. Prognostics provides a way to assess remaining useful life of a capacitor based on its current state of health and its anticipated future usage and operational conditions. We present here also, experimental results of an accelerated aging test under electrical stresses. The data obtained in this test form the basis for a remaining life prediction algorithm where a model of the degradation process is suggested. This preliminary remaining life prediction algorithm serves as a demonstration of how prognostics methodologies could be used for electrolytic capacitors. In addition, the use degradation progression data from accelerated aging, provides an avenue for validation of applications of the Kalman filter based prognostics methods typically used for remaining useful life predictions in other applications.

  1. Optical fiber feasibility study in Accelerated Pavement Testing facility

    Bueche, N.; Rychen, P.; Dumont, A.-G.; Santagata, E.

    2009-01-01

    The presented research has been carried out within the European project Intelligent Roads (INTRO). The major objective followed was to assess the potential of optical fiber for pavement monitoring in comparison with classical strain gauges. Thus, both measurement devices have been tested under the same conditions in a full scale Accelerated Pavement Testing (APT) at LAVOC. This facility allows the user to control different parameters such as loading configuration and temperature and, as a mat...

  2. Results from some anode wire aging tests

    Using twin setups to test anode wire aging in small gas avalanche tubes, a variety of different gas mixtures were tried and other parameters were varied to study their effects upon the gain drop, nomalized to charge transfer: - 1/Q dI/I. This was found to be quite sensitive to the purity of the gases, and also sensitive to the nominal gain and the gas flow rate. The wire surface material can also significantly affect the aging, as can additives, such as ethanol or water vapor. Certain gas mixtures have been found to be consistent with zero aging at the sensitivity level of this technique

  3. Free-electron laser results from the Advanced Test Accelerator

    PALADIN is a 10.6-μm FEL amplifier experiment operating at the Lawrence Livermore National Laboratory's Advanced Test Accelerator, an induction linear accelerator designed to produce a 45-MeV, 10-kA electron beam. With a 15-m long wiggler, PALADIN demonstrated 27 dB of exponential gain from a 14-kW input signal. With a 5-MW input signal, the amplifier saturated after 10 dB of gain. The exponentially growing signal in the unsaturated amplifier was clearly seen to be gain guided by the electron beam. 7 refs., 8 figs

  4. Operation of the graded-β electron test accelerator

    The Electron Test Accelerator has been built to model the behaviour of the high energy portion of a proton linear accelerator which would be suitable for breeding fissile material. The test accelerator and its control systems have been tested at 100% duty factor producing a beam of electrons at 1.5 MeV and currents up to 20 mA where the incident rf power is shared equally between the structure dissipation and the beam loading. The structure has performed satisfactorily in all respects at dissipation power densities up to 5 kW/cell where the mean energy gradient was 1.1 MeV/m. Experiments have been done on the beam loading effects in the coupling of the transmission line to the cavity, the amplitude depression in and phase tilt along the structure, and the phase lag of the structure field. The phase acceptance, the variation of transmission with buncher-accelerator phase shift and the beam energy spread are in qualitative agreement with beam dynamics calculations. (author)

  5. High-Voltage Terminal Test of Test Stand for 1-MV Electrostatic Accelerator

    Park, Sae-Hoon

    2015-01-01

    The Korea Multipurpose Accelerator Complex (KOMAC) has been developing a 300-kV test stand for a 1-MV electrostatic accelerator ion source. The ion source and accelerating tube will be installed in a high-pressure vessel. The ion source in the high-pressure vessel is required to have a high reliability. The test stand has been proposed and developed to confirm the stable operating conditions of the ion source. The ion source will be tested at the test stand to verify the long-time operating conditions. The test stand comprises a 300-kV high-voltage terminal, a battery for the ion-source power, a 60-Hz inverter, 200-MHz RF power, a 5-kV extraction power supply, a 300-kV accelerating tube, and a vacuum system. The results of the 300-kV high-voltage terminal tests are presented in this paper.

  6. Improving Bone Microarchitecture in Aging with Diosgenin Treatment: A Study in Senescence-Accelerated OXYS Rats.

    Tikhonova, Maria A; Ting, Che-Hao; Kolosova, Nataliya G; Hsu, Chao-Yu; Chen, Jian-Horng; Huang, Chi-Wen; Tseng, Ging-Ting; Hung, Ching-Sui; Kao, Pan-Fu; Amstislavskaya, Tamara G; Ho, Ying-Jui

    2015-10-31

    Osteoporosis is a major disease associated with aging. We have previously demonstrated that diosgenin prevents osteoporosis in both menopause and D-galactose-induced aging rats. OXYS rats reveal an accelerated senescence and are used as a suitable model of osteoporosis. The aim of the present study was to analyze microarchitecture and morphological changes in femur of OXYS rats using morphological tests and microcomputed tomography scanning, and to evaluate the effects of oral administration of diosgenin at 10 and 50 mg/kg/day on femur in OXYS rats. The result showed that, compared with age-matched Wistar rats, the femur of OXYS rats revealed lower bone length, bone weight, bone volume, frame volume, frame density, void volume, porosity, external and internal diameters, cortical bone area, BV/TV, Tb.N, and Tb.Th, but higher Tb.Sp. Eight weeks of diosgenin treatment decreased porosity and Tb.Sp, but increased BV/TV, cortical bone area, Tb.N and bone mineral density, compared with OXYS rats treated with vehicle. These data reveal that microarchitecture and morphological changes in femur of OXYS rats showed osteoporotic aging features and suggest that diosgenin may have beneficial effects on aging-induced osteoporosis. PMID:26387656

  7. Klystron pulse modulator of linear electron accelerator: test results

    Z. Zimek

    2009-12-01

    Full Text Available Purpose: The purpose of the paper is to describe Klystron pulse modulator of linear electron accelerator.Design/methodology/approach: TH-2158 klystron modulator experimental model is based on semiconductor switch HTS 181-160 FI (acceptable current load 1600 A, and voltage up to 18 kV. The results of test measurements carried out during modulator starting up period are presented in this work. TH-2158 klystron was used as a load. The klystron was connected to the second winding of the pulse HV transformer with 1:10 windings turn ratio. The examined modulator is equipped with safety shutdown circuitry for protection against current overload that may appear at IGBT switch in the case of short-circuiting happened in klystron and waveguide system.Findings: Linear electron accelerator type LAE 10/15 with electron energy 10 MeV and beam power up to 15 kW was designed and completed at Institute of Nuclear Chemistry and Technology. This accelerator was installed in facility for radiation sterilization single use medical devices, implants and tissue grafts. The standing wave accelerating section was selected. Microwave energy used for accelerating process is provided by klystron type TH-2158 working at frequency 2856 MHz.Practical implications: Described HV pulse modulator which designed and constructed for klystron TH-2158 was preliminary tested to evaluate the quality of the klystron HV and load current pulses and optimized selected component parameters. Obtained experimental results are better than those which were predicted by computer simulation method.Originality/value: Description of Klystron pulse modulator of linear electron accelerator.

  8. A general Bayes weibull inference model for accelerated life testing

    This article presents the development of a general Bayes inference model for accelerated life testing. The failure times at a constant stress level are assumed to belong to a Weibull distribution, but the specification of strict adherence to a parametric time-transformation function is not required. Rather, prior information is used to indirectly define a multivariate prior distribution for the scale parameters at the various stress levels and the common shape parameter. Using the approach, Bayes point estimates as well as probability statements for use-stress (and accelerated) life parameters may be inferred from a host of testing scenarios. The inference procedure accommodates both the interval data sampling strategy and type I censored sampling strategy for the collection of ALT test data. The inference procedure uses the well-known MCMC (Markov Chain Monte Carlo) methods to derive posterior approximations. The approach is illustrated with an example

  9. Next Linear Collider Test Accelerator conceptual design report

    This document presents the scientific justification and the conceptual design for the open-quotes Next Linear Collider Test Acceleratorclose quotes (NLCTA) at SLAC. The goals of the NLCTA are to integrate the new technologies of X-band accelerator structures and rf systems being developed for the Next Linear Collider, to measure the growth of the open-quotes dark currentclose quotes generated by rf field emission in the accelerator, to demonstrate multi-bunch beam-loading energy compensation and suppression of higher-order deflecting modes, and to measure any transverse components of the accelerating field. The NLCTA will be a 42-meter-long beam line consisting, consecutively, of a thermionic-cathode gun, an X-band buncher, a magnetic chicane, six 1.8-meter-long sections of 11.4-GHz accelerator structure, and a magnetic spectrometer. Initially, the unloaded accelerating gradient will be 50 MV/m. A higher-gradient upgrade option eventually would increase the unloaded gradient to 100 MV/m

  10. Towards Accelerated Aging Methodologies and Health Management of Power MOSFETs

    National Aeronautics and Space Administration — Understanding aging mechanisms of electronic components is of extreme importance in the aerospace domain where they are part of numerous critical subsystems...

  11. Anode wire aging tests with selected gases

    As a continuation of earlier wire aging investigations, additional candidates for wire chamber gas and wire have been tested. These include the gases: argon/ethane, HRS gas, dimethyl ether, carbon dioxide/ethane, and carbon tetrafluoride/isobutane. Wires used were: gold- plated tungsten, Stablohm, Nicotin, and Stainless Steel. Measurements were made of the effects upon wire aging of impurities from plumbing materials or contamination from various types of oil. Attempts were made to induce wire aging by adding measured amounts of oxygen and halogen (methyl chloride) with negative results. In this paper, the possible role of electronegativity in the wire aging process is discussed, and measurements of electronegativity are made with several single carbon Freons, using both an electron capture detector and a wire chamber operating with dimethyl ether

  12. The influence of age in usability testing.

    Sonderegger, Andreas; Schmutz, Sven; Sauer, Juergen

    2016-01-01

    The effects of age in usability testing were examined in an experiment. Sixty users from two age groups (M = 23.0 yrs, M = 58.1 yrs) operated two technical devices (keyboard-based and touchscreen-based smartphones). In addition to various performance measures (e.g. task completion time, task completion rate), several subjective measures were taken (e.g. perceived usability, affect, and workload). The results showed better performance scores for younger adults than older adults for task completion time. For older adult users there was a mismatch between usability ratings and task completion time but not between usability ratings and task completion rate. Age-related differences in the importance of speed and accuracy in task completion point to the need to consider more strongly the factor user age in usability research and practice. PMID:26360221

  13. GPU-Accelerated Molecular Modeling Coming Of Age

    Stone, John E.; Hardy, David J.; Ivan S. Ufimtsev; Schulten, Klaus

    2010-01-01

    Graphics processing units (GPUs) have traditionally been used in molecular modeling solely for visualization of molecular structures and animation of trajectories resulting from molecular dynamics simulations. Modern GPUs have evolved into fully programmable, massively parallel co-processors that can now be exploited to accelerate many scientific computations, typically providing about one order of magnitude speedup over CPU code and in special cases providing speedups of two orders of magnit...

  14. Delayed and accelerated aging share common longevity assurance mechanisms

    B. Schumacher; I. van der Pluijm; M.J. Moorhouse; T. Kosteas; A.R. Robinson; Y. Suh; T.M. Breit; H. van Steeg; L.J. Niedernhofer; W. van IJcken; A. Bartke; S.R. Spindler; J.H.J. Hoeijmakers; G.T.J. van der Horst; G.A. Garinis

    2008-01-01

    Mutant dwarf and calorie-restricted mice benefit from healthy aging and unusually long lifespan. In contrast, mouse models for DNA repair-deficient progeroid syndromes age and die prematurely. To identify mechanisms that regulate mammalian longevity, we quantified the parallels between the genome-wi

  15. Color change of composite resins subjected to accelerated artificial aging

    Denise Cremonezzi Tornavoi

    2013-01-01

    Conclusions: All composite resins presented unacceptable color changes after 382 h of aging and different composite resins with same hue, presented different colors before being subjected to the aging process (B2 and C2 and after (B2. It was also observed color difference within a group of the same composite resin and same hue.

  16. Limitations of predicting in vivo biostability of multiphase polyurethane elastomers using temperature-accelerated degradation testing.

    Padsalgikar, Ajay; Cosgriff-Hernandez, Elizabeth; Gallagher, Genevieve; Touchet, Tyler; Iacob, Ciprian; Mellin, Lisa; Norlin-Weissenrieder, Anna; Runt, James

    2015-01-01

    Polyurethane biostability has been the subject of intense research since the failure of polyether polyurethane pacemaker leads in the 1980s. Accelerated in vitro testing has been used to isolate degradation mechanisms and predict clinical performance of biomaterials. However, validation that in vitro methods reproduce in vivo degradation is critical to the selection of appropriate tests. High temperature has been proposed as a method to accelerate degradation. However, correlation of such data to in vivo performance is poor for polyurethanes due to the impact of temperature on microstructure. In this study, we characterize the lack of correlation between hydrolytic degradation predicted using a high temperature aging model of a polydimethylsiloxane-based polyurethane and its in vivo performance. Most notably, the predicted molecular weight and tensile property changes from the accelerated aging study did not correlate with clinical explants subjected to human biological stresses in real time through 5 years. Further, DMTA, ATR-FTIR, and SAXS experiments on samples aged for 2 weeks in PBS indicated greater phase separation in samples aged at 85°C compared to those aged at 37°C and unaged controls. These results confirm that microstructural changes occur at high temperatures that do not occur at in vivo temperatures. In addition, water absorption studies demonstrated that water saturation levels increased significantly with temperature. This study highlights that the multiphase morphology of polyurethane precludes the use of temperature accelerated biodegradation for the prediction of clinical performance and provides critical information in designing appropriate in vitro tests for this class of materials. PMID:24810790

  17. Mechanical stability study for Integrable Optics Test Accelerator at Fermilab

    McGee, M W; Carlson, K; Leibfritz, J; Nobrega, L; Valishev, A

    2016-01-01

    The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p+) diagnostic test ring. A heavy low frequency steel floor girder is proposed as the primary tier for IOTA device component support. Two design lengths; (8) 3.96 m and (2) 3.1 m long girders with identical cross section completely encompass the ring. This study focuses on the 3.96 m length girder and the development of a working prototype. Hydrostatic Level Sensor (HLS), temperature, metrology and fast motion measurements characterize the anticipated mechanical stability of the IOTA ring.

  18. Mechanical Stability Study for Integrable Optics Test Accelerator at Fermilab

    McGee, Mike [Fermilab; Andrews, Richard [Fermilab; Carlson, Kermit [Fermilab; Leibfritz, Jerry [Fermilab; Nobrega, Lucy [Fermilab; Valishev, Alexander [Fermilab

    2016-07-01

    The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p⁺) diagnostic test ring. A heavy low frequency steel floor girder is proposed as the primary tier for IOTA device component support. Two design lengths; (8) 4 m and (2) 2.8 m long girders with identical cross section completely encompass the ring. This study focuses on the 4 m length girder and the development of a working prototype. Hydrostatic Level Sensor (HLS), temperature, metrology and fast motion measurements characterize the anticipated mechanical stability of the IOTA ring.

  19. European accelerator facilities for single event effects testing

    Adams, L.; Nickson, R.; Harboe-Sorensen, R. [ESA-ESTEC, Noordwijk (Netherlands); Hajdas, W.; Berger, G.

    1997-03-01

    Single event effects are an important hazard to spacecraft and payloads. The advances in component technology, with shrinking dimensions and increasing complexity will give even more importance to single event effects in the future. The ground test facilities are complex and expensive and the complexities of installing a facility are compounded by the requirement that maximum control is to be exercised by users largely unfamiliar with accelerator technology. The PIF and the HIF are the result of experience gained in the field of single event effects testing and represent a unique collaboration between space technology and accelerator experts. Both facilities form an essential part of the European infrastructure supporting space projects. (J.P.N.)

  20. Brookhaven Accelerator Test Facility photocathode gun and transport beamline

    We present an analysis of the electron beam emitted from a laser driven photocathode injector (Gun, operating at 2856 MHZ), through a Transport beamline, to the LINAC entrance for the Brookhaven Accelerator Test Facility (ATF). The beam parameters including beam energy, and emittance are calculated. Some of our results, are tabulated and the phase plots of the beam parameters, from Cathode, through the Transport line elements, to the LINAC entrance, are shown

  1. Design of Accelerated Fatigue Tests for Flame Free Refrigeration Fittings

    Wilson, Michael; Bowers, Chad D.

    2014-01-01

    Refrigerant leakage from failed braze joints is a multi-billion dollar problem for the global HVAC&R industry. Leaks are typically caused due to mechanical fatigue from extreme pressure cycling, temperature cycling including exposure to freeze/thaw cycles, or vibrational wear induced from rotating electrical machinery. Three tests to accelerate mechanical fatigue were devised to simulate real world extreme conditions to determine possible failure modes of refrigerant components. The first tes...

  2. Accelerated ageing of an EAF black slag by carbonation and percolation for long-term behaviour assessment.

    Gurtubay, L; Gallastegui, G; Elias, A; Rojo, N; Barona, A

    2014-07-01

    The efficient reuse of industrial by-products, such as the electric arc furnace (EAF) black slag, is still hindered by concern over their long-term behaviour in outdoor environments. The aim of this study was to develop an accelerated ageing method to simulate the long-term natural carbonation of EAF slag exposed to the elements. The degree of carbonation achieved in a freshly produced slag after accelerated ageing and in a slag used on a fifteen-year-old unpaved road was very similar. The influence of particle size on accelerated carbonation was assessed, with it being concluded that the slag sample with a particle size bigger than 5-6 mm underwent slight carbonation over time when it was exposed to CO2. The accelerated ageing procedure based on percolating a previously carbonated water solution through the slag column allowed gradual leaching with simulated acid rain, as well as providing information about the gradual and total chemical release from the slag. Three classification groups were established according to the release rate of the determined elements. The joint use of the accelerated carbonation method and the percolation test is proposed as a useful tool for environmental risk assessment concerning the long-term air exposure of EAF black slag. PMID:24726964

  3. Accelerated artificial aging of particleboards from residues of CCB treated Pinus sp. and castor oil resin

    Marília da Silva Bertolini

    2013-04-01

    Full Text Available Tests simulating exposure to severe weather conditions have been relevant in seeking new applications for particleboard. This study aimed to produce particleboards with residues of CCB (chromium-copper-boron oxides impregnated Pinus sp. and castor oil-based polyurethane resin, and to evaluate their performance before and after artificial accelerated aging. Panels were produced with different particle mass, resin content and pressing time, resulting eight treatments. Particles moisture and size distribution were determined, beyond panel physical and mechanical properties, according to NBR14810-3: 2006. After characterization, treatments B and G (small adhesive consumption and better mechanical performance, respectively were chosen to artificial aging tests. Statistical results analysis showed best performances were achieved for waterproof aged samples, of both B and G treatments. As example, in treatment B, MOR and MOE values were 23 MPa and 2,297 MPa, samples before exposure; 26 MPa and 3,185 MPa, 32 MPa and 3,982 MPa for samples after exposure (non-sealed and sealed, respectively.

  4. Chasing literacy reading and writing in an age of acceleration

    Keller, Daniel

    2013-01-01

    Arguing that composition should renew its interest in reading pedagogy and research, Chasing Literacy offers writing instructors and literacy scholars a framework for understanding and responding to the challenges posed by the proliferation of interactive and multimodal communication technologies in the twenty-first century.Employing case-study research of student reading practices, Keller explores reading-writing connections in new media contexts. He identifies a culture of acceleration-a gathering of social, educational, economic, and technological forces that reinforce the values of speed,

  5. Enzyme activity and seedling growth of soybean seeds under accelerated aging

    Yadollhhi Nooshabadi S.J.

    2013-11-01

    Full Text Available Seed aging is the main problem of seed storage. Changes of bio-chemical and reduction of seedling growth are consequence of seed deterioration. An experiment was conducted to evaluate the effects of accelerated aging on soybean seed germination indexes and enzyme activity. Seeds were incubated in closed plastic boxes for the accelerated aging treatments. Three accelerate aging regimes were performed by placing seeds at 41°C and relative humidity (RH of 90-100 % for 0, 2, 4, 6 and 8 days periods. Our results showed that increasing aging duration resulted higher reduction in germination characteristics, catalase and ascorbate peroxidase. Germination percentage, means time to germination, germination index, normal seedling percentage and enzyme activity decrease significantly.

  6. An Asset Test of the CLIC Accelerating Structure

    Transverse wakefield suppression in the CLIC (Compact Linear Collider) multibunch accelerating structure, called the TDS (Tapered Damped Structure), is achieved primarily through heavy damping. In order to verify the performance of the TDS design and the validity of the theoretical tools used to model it, a 15 GHz version of the TDS has been constructed and tested in the ASSET facility at SLAC. The test has directly demonstrated transverse wakefield suppression of over a factor 100, with an excellent agreement between the measured and the calculated wakefield

  7. Precise RF control system of the SCSS test accelerator

    We present development and performance of the low-level rf control system of the SCSS test accelerator. The low-level rf system consists of IQ modulators / demodulators and VME waveform generators / digitizers. Recent improvements of them established high-resolution phase and amplitude setting capabilities of 0.01 degree and 0.01%, respectively. In addition, temperature drifts of the injector acceleration cavities were reduced by tuning a precise temperature regulation system. The temperature fluctuation was improved to be 0.01 K rms. As a result, the rf phase and amplitude stabilities of sub-harmonic buncher cavities were achieved to be 0.02 degree rms and 0.03% rms, respectively. The saturated FEL radiation in the wavelength region of 50-60 nm is stably generated by this improvement. (author)

  8. Database requirements for the Advanced Test Accelerator project

    The database requirements for the Advanced Test Accelerator (ATA) project are outlined. ATA is a state-of-the-art electron accelerator capable of producing energetic (50 million electron volt), high current (10,000 ampere), short pulse (70 billionths of a second) beams of electrons for a wide variety of applications. Databasing is required for two applications. First, the description of the configuration of facility itself requires an extended database. Second, experimental data gathered from the facility must be organized and managed to insure its full utilization. The two applications are intimately related since the acquisition and analysis of experimental data requires knowledge of the system configuration. This report reviews the needs of the ATA program and current implementation, intentions, and desires. These database applications have several unique aspects which are of interest and will be highlighted. The features desired in an ultimate database system are outlined. 3 references, 5 figures

  9. Beam loading and cavity compensation for the Ground Test Accelerator

    The Ground Test Accelerator (GTA) will be heavily beam-loaded H- linac with tight tolerances on accelerating field parameters. The methods used in modeling the effects of beam loading in this machine are described. The response of the cavity to both beam and radio-frequency (RF) drive stimulus is derived, including the effects of cavity detuning. This derivation is not restricted to a small-signal approximation. An analytical method for synthesizing a predistortion network that decouples the amplitude and phase responses of the cavity is also outline. Simulation of performance, including beam loading, is achieved through use of a control system analysis software package. A straightforward method is presented for extrapolating this work to model large coupled structures with closely spaced parasitic modes. Results to date have enabled the RF control system designs for GTA to be optimized and have given insight into their operation. 6 refs., 10 figs

  10. Recipient aging accelerates acquired transthyretin amyloidosis after domino liver transplantation.

    Misumi, Yohei; Narita, Yasuko; Oshima, Toshinori; Ueda, Mitsuharu; Yamashita, Taro; Tasaki, Masayoshi; Obayashi, Konen; Isono, Kaori; Inomata, Yukihiro; Ando, Yukio

    2016-05-01

    Domino liver transplantation (DLT) with liver grafts from patients with hereditary transthyretin (TTR) amyloidosis has been performed throughout the world because of a severe liver graft shortage. Reports of acquired systemic TTR amyloidosis in domino liver recipients have been increasing; however, the precise pathogenesis and clinical course of acquired TTR amyloidosis remains unclear. We analyzed the relationship between the occurrence of acquired amyloidosis and clinical features in 22 consecutive domino liver donors with hereditary TTR amyloidosis (10 males and 12 females; mean age at DLT: 37.2 years; TTR mutations: V30M [n = 19], Y114C [n = 1], L55P [n = 1], and S50I [n = 1]) and 22 liver recipients (16 males and 6 females; mean age at DLT, 46.2 years). The mean times from DLT to amyloid first appearance and transplant recipient symptom onset were 8.2 years and 9.9 years, respectively. Kaplan-Meier analysis and quantification of the amyloid deposition revealed aging of recipients correlated with early de novo amyloid deposition. The sex of donors and recipients and the age, disease duration, and disease severity of donors had no significant effect on the latency of de novo amyloid deposition. In conclusion, our results demonstrate that recipient aging is associated with the early onset de novo amyloidosis. Because acquired amyloidosis will likely increase, careful follow-up for early amyloidosis detection and new treatments, including TTR stabilizers and gene-silencing therapies, are required. Liver Transplantation 22 656-664 2016 AASLD. PMID:26600212

  11. Accelerated stress testing of amorphous silicon solar cells

    Stoddard, W. G.; Davis, C. W.; Lathrop, J. W.

    1985-01-01

    A technique for performing accelerated stress tests of large-area thin a-Si solar cells is presented. A computer-controlled short-interval test system employing low-cost ac-powered ELH illumination and a simulated a-Si reference cell (seven individually bandpass-filtered zero-biased crystalline PIN photodiodes) calibrated to the response of an a-Si control cell is described and illustrated with flow diagrams, drawings, and graphs. Preliminary results indicate that while most tests of a program developed for c-Si cells are applicable to a-Si cells, spurious degradation may appear in a-Si cells tested at temperatures above 130 C.

  12. Accelerated Apoptosis Contributes to Aging-Related Hyperinflammation in Endotoxemia

    Zhou, Mian; Wu, Rongqian; Dong, Weifeng; Leong, Jennifer; Ping WANG

    2010-01-01

    Sepsis is associated with an increase in circulating levels of bacterial endotoxin. Sepsis is a particularly serious problem in the geriatric population due to the high mortality associated with it. However, it remains unknown whether this phenomenon is related to an increase of apoptosis in splenic cells. To study this, male Fischer-344 rats (young: 3-months old; aged: 24-months old) were subjected to endotoxemia by injection of LPS. Splenic samples were collected 4 h thereafter. Apoptosis w...

  13. Aging as Accelerated Accumulation of Somatic Variants : Whole-Genome Sequencing of Centenarian and Middle-Aged Monozygotic Twin Pairs

    Ye, Kai; Beekman, Marian; Lameijer, Eric-Wubbo; Zhang, Yanju; Moed, Matthijs H.; van den Akker, Erik B.; Deelen, Joris; Houwing-Duistermaat, Jeanine J.; Kremer, Dennis; Anvar, Seyed Yahya; Laros, Jeroen F. J.; Jones, David; Raine, Keiran; Blackburne, Ben; Potluri, Shobha; Long, Quan; Guryev, Victor; van der Breggen, Ruud; Westendorp, Rudi G. J.; 't Hoen, Peter A. C.; den Dunnen, Johan; van Ommen, Gert Jan B.; Willemsen, Gonneke; Pitts, Steven J.; Cox, David R.; Ning, Zemin; Boomsma, Dorret I.; Slagboom, P. Eline

    2013-01-01

    It has been postulated that aging is the consequence of an accelerated accumulation of somatic DNA mutations and that subsequent errors in the primary structure of proteins ultimately reach levels sufficient to affect organismal functions. The technical limitations of detecting somatic changes and t

  14. Accelerated lifetime testing methodology for lifetime estimation of Lithium-ion batteries used in augmented wind power plants

    Stroe, Daniel Ioan; Swierczynski, Maciej Jozef; Stan, Ana-Irina;

    2013-01-01

    The development of lifetime estimation models for Lithium-ion battery cells, which are working under highly variable mission profiles characteristic for wind power plant applications, requires a lot of expenditures and time resources. Therefore, batteries have to be tested under accelerated...... lifetime ageing conditions. This paper presents a three-stage methodology used for accelerated lifetime testing of Lithium-ion batteries. The results obtained at the end of the accelerated ageing process can be used for the parametrization of a performance-degradation lifetime model. In the proposed...... methodology both calendar and cycling lifetime tests are considered since both components are influencing the lifetime of Lithium-ion batteries. The methodology proposes also a lifetime model verification stage, where Lithium-ion battery cells are tested at normal operating conditions using an application...

  15. Metal and elastomer seal tests for accelerator applications

    The vacuum system of the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory has more than a thousand metal vacuum seals. Also, numerous elastomer seals are used throughout the AGS to seal large beam component chambers. An accelerator upgrade program is being implemented to reduce the AGS operating pressure by x100 and improve the reliability of the vacuum system. This paper describes work in progress on metal and elastomer vacuum seals to help meet those two objectives. Tests are reported on the sealing properties of a variety of metal seals used on different sealing surfaces. Results are also given on reversible sorption properties of certain elastomers. 16 refs., 6 figs., 4 tabs

  16. Simulations and Vacuum Tests of a CLIC Accelerating Structure

    Garion, C

    2011-01-01

    The Compact LInear Collider, under study, is based on room temperature high gradient structures. The vacuum specificities of these cavities are low conductance, large surface areas and a non-baked system. The main issue is to reach UHV conditions (typically 10-7 Pa) in a system where the residual vacuum is driven by water outgassing. A finite element model based on an analogy thermal/vacuum has been built to estimate the vacuum profile in an accelerating structure. Vacuum tests are carried out in a dedicated set-up, the vacuum performances of different configurations are presented and compared with the predictions.

  17. Testing of accelerator dipoles in pressurized superfluid helium

    Two superconducting accelerator dipole magnets, with different internal construction features, have been tested in pressurized superfluid helium (1.8K, 1.2 atmosphere) as well as in regular pool boiling helium (4.4K, 1.2 atmosphere) helium. The coils of one magnet were moderately pre-stressed, and 4.2K design performance was rapidly achieved in the superfluid. The other magnet had very low coil pre-stress, reduced helium ventilation, and displayed degraded performance, even in the superfluid helium

  18. Search for reducing methodology of acceleration aging time in reversed sequential application of heat and radiation using numerical computational program

    Two consecutive numerical calculations on degradation of polymeric insulations under thermal and radiation environment are carried out to simulate so-called reversal sequential acceleration test. The calculation is aiming at searching the test conditions which provide material damage equivalent to the case of simultaneous exposure of heat and radiation. The total aging time in reversal sequential method becomes the shortest if all amount of target degradation is assigned to radiation process with the strongest allowable dose rate. If the total time becomes shorter than this using the heating process, radiation process in any dose rate conditions would prolong the testing time. (author)

  19. Acceleration of ageing processes by ionizing radiation. 3

    The behaviour of renal cells of young, old and irradiated young rats has been studied in cell cultures. There are differences between young and old donors in the cell counts obtained after trypsinization of equal amounts of renal tissue as well as in the behaviour of the cells in cell cultures. The intercellular substance in the kidney increases with increasing age and cellular output becomes smaller. Whereas cells of young donors grew in the culture and formed a monolayer cellular lawn after 14 days, cell cultures of old donors grew very sparsely and degenerated early. After irradiation of young donors with 600 R we found the following results depending on the time following irradiation: If the animals were killed immediately after irradiation neither the cellular output after trypsinization nor the behaviour of the cells in culture differed from those of non-irradiated young controls. With regard to the criteria studied cells obtained 7 days after irradiation resembled those of old donors. (author)

  20. Accelerated Testing of UH-60 Viscous Bearings for Degraded Grease Fault

    Dykas, Brian; Hood, Adrian; Krantz, Timothy; Klemmer, Marko

    2015-01-01

    An accelerated aging investigation of critical aviation bearings lubricated with MIL-PRF- 81322 grease was conducted to derive an understanding of the mechanisms of grease degradation and loss of lubrication over time. The current study focuses on UH-60 Black Hawk viscous damper bearings supporting the tail rotor driveshaft, which were subjected to more than 5800 hours of testing in a heated environment to accelerate the deterioration of the grease. The mechanism of grease degradation is a reduction in the oil/thickener ratio rather than the expected chemical degradation of grease constituents. Over the course of testing, vibration and temperature monitoring of bearings was conducted and trends for failing bearings are presented.

  1. Effect of dietary, social, and lifestyle determinants of accelerated aging and its common clinical presentation: A survey study

    Samarakoon, S. M. S.; Chandola, H. M.; Ravishankar, B.

    2011-01-01

    Aging is unavoidable and natural phenomenon of life. Modern gerontologists are realizing the fact that aging is a disease, which Ayurveda had accepted as natural disease since long. Rate of aging is determined by one's biological, social, lifestyle, and psychological conditions and adversity of which leads to accelerated form of aging (Akalaja jara or premature aging). The aim of this study is to identify potential factors that may accelerate aging in the context of dietry factors, lifestyle ...

  2. Bayesian optimal design of step stress accelerated degradation testing

    Xiaoyang Li; Mohammad Rezvanizaniani; Zhengzheng Ge; Mohamed Abuali; Jay Lee

    2015-01-01

    This study presents a Bayesian methodology for de-signing step stress accelerated degradation testing (SSADT) and its application to batteries. First, the simulation-based Bayesian de-sign framework for SSADT is presented. Then, by considering his-torical data, specific optimal objectives oriented Kul back–Leibler (KL) divergence is established. A numerical example is discussed to il ustrate the design approach. It is assumed that the degrada-tion model (or process) fol ows a drift Brownian motion;the accele-ration model fol ows Arrhenius equation; and the corresponding parameters fol ow normal and Gamma prior distributions. Using the Markov Chain Monte Carlo (MCMC) method and WinBUGS software, the comparison shows that KL divergence is better than quadratic loss for optimal criteria. Further, the effect of simulation outliers on the optimization plan is analyzed and the preferred sur-face fitting algorithm is chosen. At the end of the paper, a NASA lithium-ion battery dataset is used as historical information and the KL divergence oriented Bayesian design is compared with maxi-mum likelihood theory oriented local y optimal design. The results show that the proposed method can provide a much better testing plan for this engineering application.

  3. Senescence-accelerated mouse (SAM): a biogerontological resource in aging research.

    Takeda, T

    1999-01-01

    The senescence-accelerated mouse (SAM), consisting of 14 senescence-prone inbred strains (SAMP) and 4 senescence-resistant inbred strains (SAMR) has been under development since 1970 through the selective inbreeding of AKR/J strain mice donated by the Jackson laboratory in 1968, based on the data of the grading score of senescence, life span, and pathologic phenotypes. The characteristic feature of aging common to all SAMP and SAMR mice is accelerated senescence and normal aging, respectively. Furthermore, SAMP and SAMR strains manifest various pathobiological phenotypes which include such neurobiological phenotypes as deficits in learning and memory, emotional disorders, abnormal circadian rhythms, brain atrophy, hearing impairment, etc., and are often characteristic enough to differentiate the strains. Various efforts are currently being made using the SAM model to clarify the underlying mechanisms in accelerated senescence as well as the etiopathogenic mechanisms in age-associated pathobiologies. Genetic background and significance of SAM development are discussed. PMID:10537019

  4. Experimental induction of type 2 diabetes in aging-accelerated mice triggered Alzheimer-like pathology and memory deficits.

    Mehla, Jogender; Chauhan, Balwantsinh C; Chauhan, Neelima B

    2014-01-01

    Alzheimer's disease (AD) is an age-dependent neurodegenerative disease constituting ~95% of late-onset non-familial/sporadic AD, and only ~5% accounting for early-onset familial AD. Availability of a pertinent model representing sporadic AD is essential for testing candidate therapies. Emerging evidence indicates a causal link between diabetes and AD. People with diabetes are >1.5-fold more likely to develop AD. Senescence-accelerated mouse model (SAMP8) of accelerated aging displays many features occurring early in AD. Given the role played by diabetes in the pre-disposition of AD, and the utility of SAMP8 non-transgenic mouse model of accelerated aging, we examined if high fat diet-induced experimental type 2 diabetes in SAMP8 mice will trigger pathological aging of the brain. Results showed that compared to non-diabetic SAMP8 mice, diabetic SAMP8 mice exhibited increased cerebral amyloid-β, dysregulated tau-phosphorylating glycogen synthase kinase 3β, reduced synaptophysin immunoreactivity, and displayed memory deficits, indicating Alzheimer-like changes. High fat diet-induced type 2 diabetic SAMP8 mice may represent the metabolic model of AD. PMID:24121970

  5. Accelerated Lifetime Testing Methodology for Lifetime Estimation of Lithium-ion Batteries used in Augmented Wind Power Plants

    Stroe, Daniel Ioan; Swierczynski, Maciej Jozef; Stan, Ana-Irina;

    2014-01-01

    The development of lifetime estimation models for Lithium-ion battery cells, which are working under highly variable mission profiles characteristic for wind power plant applications, requires a lot of expenditures and time resources. Therefore, batteries have to be tested under accelerated...... lifetime ageing conditions. This paper presents a three-stage methodology used for accelerated lifetime testing of Lithium ion batteries. The results obtained at the end of the accelerated ageing process were used for the parametrization of a performance-degradation lifetime model, which is able to predict...... both the capacity fade and the power capability decrease of the selected Lithium-ion battery cells. In the proposed methodology both calendar and cycling lifetime tests were considered since both components are influencing the lifetime of Lithium-ion batteries. Furthermore, the proposed methodology was...

  6. Mir Cooperative Solar Array Project Accelerated Life Thermal Cycling Test

    Hoffman, David J.; Scheiman, David A.

    1996-01-01

    The Mir Cooperative Solar Array (MCSA) project was a joint U.S./Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA will be used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station. The MCSA was brought to Mir by space shuttle Atlantis in November 1995. This report describes an accelerated thermal life cycle test which was performed on two samples of the MCSA. In eight months time, two MCSA solar array 'mini' panel test articles were simultaneously put through 24,000 thermal cycles. There was no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early and removed from consideration. The nature of the performance degradation caused by this one cell is briefly discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the U.S. solar cell modules with the Russian support structure would be able to withstand at least 24,000 thermal cycles (4 years on-orbit). This was considered a successful development test.

  7. Accelerated fat cell aging links oxidative stress and insulin resistance in adipocytes

    Finny Monickaraj; Sankaramoorthy Aravind; Pichamoorthy Nandhini; Paramasivam Prabu; Chandrakumar Sathishkumar; Viswanathan Mohan; Muthuswamy Balasubramanyam

    2013-03-01

    Telomere shortening is emerging as a biological indicator of accelerated aging and aging-related diseases including type 2 diabetes. While telomere length measurements were largely done in white blood cells, there is lack of studies on telomere length in relation to oxidative stress in target tissues affected in diabetes. Therefore, the aim of this study is to induct oxidative stress in adipocytes and to test whether these adipocytes exhibit shortened telomeres, senescence and functional impairment. 3T3-L1 adipocytes were subjected to oxidative stress and senescence induction by a variety of means for 2 weeks (exogenous application of H2O2, glucose oxidase, asymmetric dimethylarginine (ADMA) and glucose oscillations). Cells were probed for reactive oxygen species generation (ROS), DNA damage, mRNA and protein expression of senescent and pro-inflammatory markers, telomere length and glucose uptake. Compared to untreated cells, both ROS generation and DNA damage were significantly higher in cells subjected to oxidative stress and senescence. Adipocytes subjected to oxidative stress also showed shortened telomeres and increased mRNA and protein expression of p53, p21, TNF and IL-6. Senescent cells were also characterized by decreased levels of adiponectin and impaired glucose uptake. Briefly, adipocytes under oxidative stress exhibited increased ROS generation, DNA damage, shortened telomeres and switched to senescent/pro-inflammatory phenotype with impaired glucose uptake.

  8. Long-Term Flexural Behaviors of GFRP Reinforced Concrete Beams Exposed to Accelerated Aging Exposure Conditions

    Yeonho Park

    2014-06-01

    Full Text Available This study investigates the impact of accelerated aging conditions on the long-term flexural behavior and ductility of reinforced concrete (RC members with glass fiber-reinforced polymer (GFRP bars (RC-GFRP specimen and steel bars (RC-steel specimen. A total of thirty six specimens were designed with different amounts of reinforcement with three types of reinforcing bars (i.e., helically wrapped GFRP, sand-coated surface GFRP and steel. Eighteen specimens were subjected to sustained loads and accelerated aging conditions (i.e., 47 °C and 80% relative humidity in a chamber. The flexural behavior of specimens under 300-day exposure was compared to that of the companion specimens without experiencing accelerated aging conditions. Results indicate that the accelerated aging conditions reduced flexural capacity in not only RC-steel, but also RC-GFRP specimens, with different rates of reduction. Different types of GFRP reinforcement exhibited different rates of degradation of the flexural capacity when embedded in concrete under the same exposure conditions. Several existing models were compared with experimental results for predicting the deflection and deformability index for specimens. Bischoff and Gross’s model exhibited an excellent prediction of the time-dependent deflections. Except for the deformability index proposed by Jaeger, there was no general trend related to the aging duration. This study recommends the need for further investigation on the prediction of the deformability index.

  9. Power-conditioning system for the Advanced Test Accelerator

    The Advanced Test Accelerator (ATA) is a pulsed, linear induction, electron accelerator currently under construction and nearing completion at Lawrence Livermore National Laboratory's Site 300 near Livermore, California. The ATA is a 50 MeV, 10 kA machine capable of generating electron beam pulses at a 1 kHz rate in a 10 pulse burst, 5 pps average, with a pulse width of 70 ns FWHM. Ten 18 kV power supplies are used to charge 25 capacitor banks with a total energy storage of 8 megajoules. Energy is transferred from the capacitor banks in 500 microsecond pulses through 25 Command Resonant Charge units (CRC) to 233 Thyratron Switch Chassis. Each Thyratron Switch Chassis contains a 2.5 microfarad capacitor and is charged to 25 kV (780 joules) with voltage regulation of +- .05%. These capacitors are switched into 10:1 step-up resonant transformers to charge 233 Blumleins to 250 kV in 20 microseconds. A magnetic modulator is used instead of a Blumlein to drive the grid of the injector

  10. Cosmic acceleration without dark energy: background tests and thermodynamic analysis

    A cosmic scenario with gravitationally induced particle creation is proposed. In this model the Universe evolves from an early to a late time de Sitter era, with the recent accelerating phase driven only by the negative creation pressure associated with the cold dark matter component. The model can be interpreted as an attempt to reduce the so-called cosmic sector (dark matter plus dark energy) and relate the two cosmic accelerating phases (early and late time de Sitter expansions). A detailed thermodynamic analysis including possible quantum corrections is also carried out. For a very wide range of the free parameters, it is found that the model presents the expected behavior of an ordinary macroscopic system in the sense that it approaches thermodynamic equilibrium in the long run (i.e., as it nears the second de Sitter phase). Moreover, an upper bound is found for the Gibbons–Hawking temperature of the primordial de Sitter phase. Finally, when confronted with the recent observational data, the current 'quasi'-de Sitter era, as predicted by the model, is seen to pass very comfortably the cosmic background tests

  11. Development of an accelerated test for Internal Sulfate Attack study

    Khelil Nacim; Aubert Jean-Emmanuel; Escadeillas Gilles

    2014-01-01

    Internal Sulfate Attack (ISA) is a pathology that occurs under certain conditions in concrete having undergone heating above 70 °C at early age (through heating in pre-casting industry or due to hydration in large concrete parts). This reaction deemed very slow, numerous methods to speed up reactions leading to delayed ettringite formation have been developed. These methods are all based on the material damage. Another type of test is currently under development. It is based on rehabilitation...

  12. Towards Accelerated Aging Methodologies and Health Management of Power MOSFETs (Technical Brief)

    Celaya, Jose R.; Patil, Nishad; Saha, Sankalita; Wysocki, Phil; Goebel, Kai

    2009-01-01

    Understanding aging mechanisms of electronic components is of extreme importance in the aerospace domain where they are part of numerous critical subsystems including avionics. In particular, power MOSFETs are of special interest as they are involved in high voltage switching circuits such as drivers for electrical motors. With increased use of electronics in aircraft control, it becomes more important to understand the degradation of these components in aircraft specific environments. In this paper, we present an accelerated aging methodology for power MOSFETs that subject the devices to indirect thermal overstress during high voltage switching. During this accelerated aging process, two major modes of failure were observed - latch-up and die attach degradation. In this paper we present the details of our aging methodology along with details of experiments and analysis of the results.

  13. A flexible and configurable system to test accelerator magnets

    Jerzy M. Nogiec et al.

    2001-07-20

    Fermilab's accelerator magnet R and D programs, including production of superconducting high gradient quadrupoles for the LHC insertion regions, require rigorous yet flexible magnetic measurement systems. Measurement systems must be capable of handling various types of hardware and extensible to all measurement technologies and analysis algorithms. A tailorable software system that satisfies these requirements is discussed. This single system, capable of distributed parallel signal processing, is built on top of a flexible component-based framework that allows for easy reconfiguration and run-time modification. Both core and domain-specific components can be assembled into various magnet test or analysis systems. The system configured to comprise a rotating coil harmonics measurement is presented. Technologies as Java, OODB, XML, JavaBeans, software bus and component-based architectures are used.

  14. Traumatic stress, oxidative stress and posttraumatic stress disorder: neurodegeneration and the accelerated-aging hypothesis

    Miller, Mark W.; Sadeh, Naomi

    2014-01-01

    Posttraumatic stress disorder (PTSD) is associated with elevated risk for a variety of age-related diseases and neurodegeneration. In this paper, we review evidence relevant to the hypothesis that chronic PTSD constitutes a form of persistent life stress that potentiates oxidative stress (OXS) and accelerates cellular aging. We provide an overview of empirical studies that have examined the effects of psychological stress on OXS, discuss the stress-perpetuating characteristics of PTSD, and th...

  15. Diabetes exacerbates amyloid and neurovascular pathology in aging-accelerated mice

    Currais, Antonio; Prior, Marguerite; Lo, David; Jolivalt, Corinne; Schubert, David; Maher, Pamela

    2012-01-01

    Mounting evidence supports a link between diabetes, cognitive dysfunction and aging. However, the physiological mechanisms by which diabetes impacts brain function and cognition are not fully understood. To determine how diabetes contributes to cognitive dysfunction and age-associated pathology, we used streptozotocin to induce type 1 diabetes (T1D) in senescence-accelerated prone 8 (SAMP8) and senescence-resistant 1 (SAMR1) mice. Contextual fear conditioning demonstrated that T1D resulted in...

  16. The age of the universe, the Hubble constant, the accelerated expansion and the Hubble effect

    Soares, Domingos

    2009-01-01

    The idea of an accelerating universe comes almost simultaneously with the determination of Hubble's constant by one of the Hubble Space Telescope Key Projects. The age of the universe dilemma is probably the link between these two issues. In an appendix, I claim that "Hubble's law" might yet to be investigated for its ultimate cause, and suggest the "Hubble effect" as the searched candidate.

  17. Linear Accelerator Test Facility at LNF Conceptual Design Report

    Valente, Paolo; Bolli, Bruno; Buonomo, Bruno; Cantarella, Sergio; Ceccarelli, Riccardo; Cecchinelli, Alberto; Cerafogli, Oreste; Clementi, Renato; Di Giulio, Claudio; Esposito, Adolfo; Frasciello, Oscar; Foggetta, Luca; Ghigo, Andrea; Incremona, Simona; Iungo, Franco; Mascio, Roberto; Martelli, Stefano; Piermarini, Graziano; Sabbatini, Lucia; Sardone, Franco; Sensolini, Giancarlo; Ricci, Ruggero; Rossi, Luis Antonio; Rotundo, Ugo; Stella, Angelo; Strabioli, Serena; Zarlenga, Raffaele

    2016-01-01

    Test beam and irradiation facilities are the key enabling infrastructures for research in high energy physics (HEP) and astro-particles. In the last 11 years the Beam-Test Facility (BTF) of the DA{\\Phi}NE accelerator complex in the Frascati laboratory has gained an important role in the European infrastructures devoted to the development and testing of particle detectors. At the same time the BTF operation has been largely shadowed, in terms of resources, by the running of the DA{\\Phi}NE electron-positron collider. The present proposal is aimed at improving the present performance of the facility from two different points of view: extending the range of application for the LINAC beam extracted to the BTF lines, in particular in the (in some sense opposite) directions of hosting fundamental physics and providing electron irradiation also for industrial users; extending the life of the LINAC beyond or independently from its use as injector of the DA{\\Phi}NE collider, as it is also a key element of the electron/...

  18. Accelerated Vascular Aging as a Paradigm for Hypertensive Vascular Disease: Prevention and Therapy.

    Barton, Matthias; Husmann, Marc; Meyer, Matthias R

    2016-05-01

    Aging is considered the most important nonmodifiable risk factor for cardiovascular disease and death after age 28 years. Because of demographic changes the world population is expected to increase to 9 billion by the year 2050 and up to 12 billion by 2100, with several-fold increases among those 65 years of age and older. Healthy aging and prevention of aging-related diseases and associated health costs have become part of political agendas of governments around the world. Atherosclerotic vascular burden increases with age; accordingly, patients with progeria (premature aging) syndromes die from myocardial infarctions or stroke as teenagers or young adults. The incidence and prevalence of arterial hypertension also increases with age. Arterial hypertension-like diabetes and chronic renal failure-shares numerous pathologies and underlying mechanisms with the vascular aging process. In this article, we review how arterial hypertension resembles premature vascular aging, including the mechanisms by which arterial hypertension (as well as other risk factors such as diabetes mellitus, dyslipidemia, or chronic renal failure) accelerates the vascular aging process. We will also address the importance of cardiovascular risk factor control-including antihypertensive therapy-as a powerful intervention to interfere with premature vascular aging to reduce the age-associated prevalence of diseases such as myocardial infarction, heart failure, hypertensive nephropathy, and vascular dementia due to cerebrovascular disease. Finally, we will discuss the implementation of endothelial therapy, which aims at active patient participation to improve primary and secondary prevention of cardiovascular disease. PMID:27118295

  19. Advanced Beamline Design for Fermilab's Advanced Superconducting Test Accelerator

    Prokop, Christopher [Northern Illinois Univ., DeKalb, IL (United States)

    2014-01-01

    The Advanced Superconducting Test Accelerator (ASTA) at Fermilab is a new electron accelerator currently in the commissioning stage. In addition to testing superconducting accelerating cavities for future accelerators, it is foreseen to support a variety of Advanced Accelerator R&D (AARD) experiments. Producing the required electron bunches with the expected flexibility is challenging. The goal of this dissertation is to explore via numerical simulations new accelerator beamlines that can enable the advanced manipulation of electron bunches. The work especially includes the design of a low-energy bunch compressor and a study of transverse-to-longitudinal phase space exchangers.

  20. Comparative study of ageing, heat treatment and accelerated carbonation for stabilization of municipal solid waste incineration bottom ash in view of reducing regulated heavy metal/metalloid leaching

    Santos, Rafael; Mertens, Gilles; Salman, Muhammad; Cizer, Özlem; Gerven, Tom Van

    2013-01-01

    This study compared the performance of four different approaches for stabilization of regulated heavy metal and metalloid leaching from municipal solid waste incineration bottom ash (MSWI-BA): (i) short term (three months) heap ageing, (ii) heat treatment, (iii) accelerated moist carbonation, and (iv) accelerated pressurized slurry carbonation. Two distinct types of MSWI-BA were tested in this study: one originating from a moving-grate furnace incineration operation treating exclusively house...

  1. Beam test of multi-bunch energy compensation system in the accelerator test facility at KEK

    A beam test of the multi-bunch energy compensation system (ECS) was performed using the ΔF method with the 2856±4.327 HMz accelerating structures in the accelerator test facility (ATF) at KEK. The 1.54 GeV S-band linac of the ATF was designed to accelerate a multi-bunch beam the consists of 20 bunches with 2.8 ns spacing. The multi-bunch beam with 2.0 x 1010 electrons/bunch has an energy deviation of about 8.5% at the end of the linac due to transient beam loading without ECS. The ATF linac is the injector of the ATF damping ring (DR), whose energy acceptance is ±0.5%. The beam loading compensation system is necessary in the ATF linac for the successful injection of multi-bunch into DR. The rf system of the linac consists of 8 regular rf units with the SLED system and 2 ECS rf units without the SLED system. The accelerating structures of the regular units are driven at 2856 MHz and the 2 ECS structures are operated with slightly different rf frequencies of 2856±4.327 MHz. In the beam test, we have succeeded in compressing the multi-bunch energy spread within the energy acceptance of the DR using ΔF ECS. The principle of the beam loading compensation system of KEK-ATF and the experimental results are described in this paper. (author)

  2. Effect of accelerated aging on the microhardness and color stability of flexible resins for dentures

    Marcelo Coelho Goiato

    2010-03-01

    Full Text Available Acrylic resins have been widely used due to their acceptable esthetics and desirable characteristics such as easy handling, good thermal conductivity, low permeability to oral fluids and color stability. Flexible resins were introduced on the market as an alternative to the use of conventional acrylic resins in the construction of complete and partial removable dentures. Although these resins present advantages in terms of esthetics and comfort, studies assessing chromatic and microhardness alterations of these materials are still scarce in the related literature. The aim of this study was to evaluate the chromatic and microhardness alterations of two commercial brands of flexible resins in comparison to the conventional resin Triplex when submitted to accelerated aging. The resins were manipulated according to manufacturers' instructions and inserted into a silicone matrix to obtain 21 specimens divided into 3 groups: Triplex, Ppflex and Valplast. Triplex presented the highest microhardness value (p < 0.05 for all the aging periods, which was significantly different from that of the other resins, followed by the values of Valplast and Ppflex. Comparison between the flexible resins (Ppflex and Valplast revealed a statistically significant difference (p < 0.05 as regards color. The flexible resin Ppflex and the conventional resin Triplex presented no statistically significant difference (p < 0.05 as regards aging. The accelerated aging significantly increased the microhardness values of the resins, with the highest values being observed for Triplex. Valplast presented the greatest chromatic alteration after accelerated aging.

  3. Accelerated atmospheric corrosion testing of electroplated gold mirror coatings

    Chu, C.-T.; Alaan, D. R.; Taylor, D. P.

    2010-08-01

    Gold-coated mirrors are widely used in infrared optics for industrial, space, and military applications. These mirrors are often made of aluminum or beryllium substrates with polished nickel plating. Gold is deposited on the nickel layer by either electroplating or vacuum deposition processes. Atmospheric corrosion of gold-coated electrical connectors and contacts was a well-known problem in the electronic industry and studied extensively. However, there is limited literature data that correlates atmospheric corrosion to the optical properties of gold mirror coatings. In this paper, the atmospheric corrosion of different electroplated gold mirror coatings were investigated with an accelerated mixed flowing gas (MFG) test for up to 50 days. The MFG test utilizes a combination of low-level air pollutants, humidity, and temperatures to achieve a simulated indoor environment. Depending on the gold coating thickness, pore corrosion started to appear on samples after about 10 days of the MFG exposure. The corrosion behavior of the gold mirror coatings demonstrated the porous nature of the electroplated gold coatings as well as the variation of porosity to the coating thickness. The changes of optical properties of the gold mirrors were correlated to the morphology of corrosion features on the mirror surface.

  4. Acceleration of age-associated methylation patterns in HIV-1-infected adults.

    Rickabaugh, Tammy M; Baxter, Ruth M; Sehl, Mary; Sinsheimer, Janet S; Hultin, Patricia M; Hultin, Lance E; Quach, Austin; Martínez-Maza, Otoniel; Horvath, Steve; Vilain, Eric; Jamieson, Beth D

    2015-01-01

    Patients with treated HIV-1-infection experience earlier occurrence of aging-associated diseases, raising speculation that HIV-1-infection, or antiretroviral treatment, may accelerate aging. We recently described an age-related co-methylation module comprised of hundreds of CpGs; however, it is unknown whether aging and HIV-1-infection exert negative health effects through similar, or disparate, mechanisms. We investigated whether HIV-1-infection would induce age-associated methylation changes. We evaluated DNA methylation levels at >450,000 CpG sites in peripheral blood mononuclear cells (PBMC) of young (20-35) and older (36-56) adults in two separate groups of participants. Each age group for each data set consisted of 12 HIV-1-infected and 12 age-matched HIV-1-uninfected samples for a total of 96 samples. The effects of age and HIV-1 infection on methylation at each CpG revealed a strong correlation of 0.49, pnetwork analysis (WGCNA) identified 17 co-methylation modules; module 3 (ME3) was significantly correlated with age (cor=0.70) and HIV-1 status (cor=0.31). Older HIV-1+ individuals had a greater number of hypermethylated CpGs across ME3 (p=0.015). In a multivariate model, ME3 was significantly associated with age and HIV status (Data set 1: βage=0.007088, p=2.08 x 10(-9); βHIV=0.099574, p=0.0011; Data set 2: βage=0.008762, p=1.27 x 10(-5); βHIV=0.128649, p=0.0001). Using this model, we estimate that HIV-1 infection accelerates age-related methylation by approximately 13.7 years in data set 1 and 14.7 years in data set 2. The genes related to CpGs in ME3 are enriched for polycomb group target genes known to be involved in cell renewal and aging. The overlap between ME3 and an aging methylation module found in solid tissues is also highly significant (Fisher-exact p=5.6 x 10(-6), odds ratio=1.91). These data demonstrate that HIV-1 infection is associated with methylation patterns that are similar to age-associated patterns and suggest that general aging

  5. Accelerator

    The invention claims equipment for stabilizing the position of the front covers of the accelerator chamber in cyclic accelerators which significantly increases accelerator reliability. For stabilizing, it uses hydraulic cushions placed between the electromagnet pole pieces and the front chamber covers. The top and the bottom cushions are hydraulically connected. The cushions are disconnected and removed from the hydraulic line using valves. (J.P.)

  6. Coffee Silverskin Extract Protects against Accelerated Aging Caused by Oxidative Agents.

    Iriondo-DeHond, Amaia; Martorell, Patricia; Genovés, Salvador; Ramón, Daniel; Stamatakis, Konstantinos; Fresno, Manuel; Molina, Antonio; Del Castillo, Maria Dolores

    2016-01-01

    Nowadays, coffee beans are almost exclusively used for the preparation of the beverage. The sustainability of coffee production can be achieved introducing new applications for the valorization of coffee by-products. Coffee silverskin is the by-product generated during roasting, and because of its powerful antioxidant capacity, coffee silverskin aqueous extract (CSE) may be used for other applications, such as antiaging cosmetics and dermaceutics. This study aims to contribute to the coffee sector's sustainability through the application of CSE to preserve skin health. Preclinical data regarding the antiaging properties of CSE employing human keratinocytes and Caenorhabditis elegans are collected during the present study. Accelerated aging was induced by tert-butyl hydroperoxide (t-BOOH) in HaCaT cells and by ultraviolet radiation C (UVC) in C. elegans. Results suggest that the tested concentrations of coffee extracts were not cytotoxic, and CSE 1 mg/mL gave resistance to skin cells when oxidative damage was induced by t-BOOH. On the other hand, nematodes treated with CSE (1 mg/mL) showed a significant increased longevity compared to those cultured on a standard diet. In conclusion, our results support the antiaging properties of the CSE and its great potential for improving skin health due to its antioxidant character associated with phenols among other bioactive compounds present in the botanical material. PMID:27258247

  7. Coffee Silverskin Extract Protects against Accelerated Aging Caused by Oxidative Agents

    Amaia Iriondo-DeHond

    2016-06-01

    Full Text Available Nowadays, coffee beans are almost exclusively used for the preparation of the beverage. The sustainability of coffee production can be achieved introducing new applications for the valorization of coffee by-products. Coffee silverskin is the by-product generated during roasting, and because of its powerful antioxidant capacity, coffee silverskin aqueous extract (CSE may be used for other applications, such as antiaging cosmetics and dermaceutics. This study aims to contribute to the coffee sector’s sustainability through the application of CSE to preserve skin health. Preclinical data regarding the antiaging properties of CSE employing human keratinocytes and Caenorhabditis elegans are collected during the present study. Accelerated aging was induced by tert-butyl hydroperoxide (t-BOOH in HaCaT cells and by ultraviolet radiation C (UVC in C. elegans. Results suggest that the tested concentrations of coffee extracts were not cytotoxic, and CSE 1 mg/mL gave resistance to skin cells when oxidative damage was induced by t-BOOH. On the other hand, nematodes treated with CSE (1 mg/mL showed a significant increased longevity compared to those cultured on a standard diet. In conclusion, our results support the antiaging properties of the CSE and its great potential for improving skin health due to its antioxidant character associated with phenols among other bioactive compounds present in the botanical material.

  8. In silico analysis of gene expression profiles in the olfactory mucosae of aging senescence-accelerated mice.

    Getchell, Thomas V; Peng, Xuejun; Green, C Paul; Stromberg, Arnold J; Chen, Kuey-Chu; Mattson, Mark P; Getchell, Marilyn L

    2004-08-01

    We utilized high-density Affymetrix oligonucleotide arrays to investigate gene expression in the olfactory mucosae of near age-matched aging senescence-accelerated mice (SAM). The senescence-prone (SAMP) strain has a significantly shorter lifespan than does the senescence-resistant (SAMR) strain. To analyze our data, we applied biostatistical methods that included a correlation analysis to evaluate sources of methodologic and biological variability; a two-sided t-test to identify a subpopulation of Present genes with a biologically relevant P-value SAMRs (SAMR-Os, 12.5 months). Volcano plots related the variability in the mean hybridization signals as determined by the two-sided t-test to fold changes in gene expression. The genes were categorized into the six functional groups used previously in gene profiling experiments to identify candidate genes that may be relevant for senescence at the genomic and cellular levels in the aging mouse brain (Lee et al. [2000] Nat Genet 25:294-297) and in the olfactory mucosa (Getchell et al. [2003] Ageing Res Rev 2:211-243), which serves several functions that include chemosensory detection, immune barrier function, xenobiotic metabolism, and neurogenesis. Because SAMR-Os and SAMP-Os have substantially different median lifespans, we related the rate constant alpha in the Gompertz equation on aging to intrinsic as opposed to environmental mechanisms of senescence based on our analysis of genes modulated during aging in the olfactory mucosa. PMID:15248299

  9. Body Acceleration as Indicator for Walking Economy in an Ageing Population.

    Giulio Valenti

    Full Text Available In adults, walking economy declines with increasing age and negatively influences walking speed. This study aims at detecting determinants of walking economy from body acceleration during walking in an ageing population.35 healthy elderly (18 males, age 51 to 83 y, BMI 25.5±2.4 kg/m2 walked on a treadmill. Energy expenditure was measured with indirect calorimetry while body acceleration was sampled at 60Hz with a tri-axial accelerometer (GT3X+, ActiGraph, positioned on the lower back. Walking economy was measured as lowest energy needed to displace one kilogram of body mass for one meter while walking (WCostmin, J/m/kg. Gait features were extracted from the acceleration signal and included in a model to predict WCostmin.On average WCostmin was 2.43±0.42 J/m/kg and correlated significantly with gait rate (r2 = 0.21, p<0.01 and regularity along the frontal (anteroposterior and lateral (mediolateral axes (r2 = 0.16, p<0.05 and r2 = 0.12, p<0.05 respectively. Together, the three variables explained 46% of the inter-subject variance (p<0.001 with a standard error of estimate of 0.30 J/m/kg. WCostmin and regularity along the frontal and lateral axes were related to age (WCostmin: r2 = 0.44, p<0.001; regularity: r2 = 0.16, p<0.05 and r2 = 0.12, p<0.05 respectively frontal and lateral.The age associated decline in walking economy is induced by the adoption of an increased gait rate and by irregular body acceleration in the horizontal plane.

  10. 15-16 MeV electron linear accelerators for nondestructive testing

    15-16 MeV electron linear accelerators for nondestructive testing (ND) are described. The accelerators are intended for ND of the articles with great thickness by means of radiographic, introscopic and tomographic methods. Main characteristics of these accelerators are presented. The automatic control system based on the PC compatible controllers is described in details