WorldWideScience

Sample records for science radiation-effects studies

  1. Activities of the National Academy of Sciences in relation to the Radiation Effects Research Foundation

    International Nuclear Information System (INIS)

    Edington, C.W.

    1991-02-01

    The activities of the National Academy of Sciences (NAS), in relation to the Radiation Effects Research Foundation (RERF), has a long history and the specific time period supported by this contract is but a small piece of the long-term continuing program. As a background, in August 1945, atomic bombs were dropped on Hiroshima (6 August) and Nagasaki (9 August). Shortly after the bombings, US medical teams joined forces with their Japanese counterparts to form a Joint Commission for the Investigation of the Effects of the Atomic Bombs. As a result of the Joint Commission's investigations, it was determined that consideration should be given to the establishment of a long-term study of the potential late health effects of exposure of the survivors to radiation from the bombs. The results obtained from RERF studies contribute the vast majority of information that provides a better understanding of radiation effects on humans. This information has been used extensively by national organizations and international committees for estimating risks associated with radiation exposures. The estimated risks developed by these independent organizations are used by government agencies around the world to establish standards for protection of individuals exposed in the occupational, medical, and general environment. Some of these results are described briefly in this report

  2. Fundamental radiation effects studies in the fusion materials program

    International Nuclear Information System (INIS)

    Doran, D.G.

    1982-01-01

    Fundamental radiation effects studies in the US Fusion Materials Program generally fall under the aegis of the Damage Analysis and Fundamental Studies (DAFS) Program. In a narrow sense, the problem addressed by the DAFS program is the prediction of radiation effects in fusion devices using data obtained in non-representative environments. From the onset, the program has had near-term and long-term components. The premise for the latter is that there will be large economic penalties for uncertainties in predictive capability. Fusion devices are expected to be large and complex and unanticipated maintenance will be costly. It is important that predictions are based on a maximum of understanding and a minimum of empiricism. Gaining this understanding is the thrust of the long-term component. (orig.)

  3. Radiation effects on non-human biota and ecosystems. Researches in National Institute of Radiological Sciences, Japan

    International Nuclear Information System (INIS)

    Yoshida, Satoshi; Ishii, Nobuyoshi; Ishikawa, Yuuji

    2008-01-01

    This paper summarizes research activities in National Institute of Radiological Sciences (NIRS) for evaluation of the radiation effects on selected terrestrial and aquatic organisms as well as the ecosystems. Seven organisms, conifers, fungi, earthworms, springtails, algae, daphnia and Medaka are presently selected to study. Most of them play important roles in Japanese ecosystems and are possibly useful for bio-indicator of the radiation effects. For the estimation of possible radiation dose, transfers of radionuclides and related elements from medium to organisms are evaluated. Dose-effect relationships of acute gamma radiation on the survival, growth, and reproduction of selected organisms have been studied. Studies on the effect of chronic gamma radiation at low dose rate were also started. In order to understand the mechanism of radiation effects and to find possible indicators of the effects, information of genome- and metagenome-wide gene expression obtained by the High Coverage Expression Profiling (HiCEP) has been collected. Evaluation of ecological effects of radiation is more challenging task. Study methods by using three-species microcosm were established, and an index for the holistic evaluation of effects on various ecological parameters was proposed. The microcosm has been simulated for its population dynamics, and mass and energy budgets as a computer simulation code. Developments of more complicated and practical model ecosystems have been started. The Denaturant Gradient Gel Electrophoresis (DGGE) has been applied on soil bacterial community in order to evaluate the radiation effects on soil ecosystems. (author)

  4. Study on effects of vitamin E on radiation effect

    International Nuclear Information System (INIS)

    Sakamoto, Sumihiko

    1974-01-01

    The effect of Vitamin E on radiation effect was studied. The X-ray (190 kV, 25 mA, 0.7 mmCu + 0.5 mmAl filter, dose rate 78 R/min) was irradiated to the whole body one hour after the administration of 1.0 g/kg of Vitamin E. The LD 50 (30) was larger in the group receiving Vitamin E than in the group which did not receive it. The rate at which tumor cells were killed was smaller in Vitamin E-treated group than in untreated group. The anoxic cell proportion in the tumor was 13% in the untreated group, and 35% in the treated group. The LD 50 (30) was largest in the group receiving 1.0 g/kg of Vitamin E. (Serizawa, K.)

  5. Experimental study on the radiation effects to the bone growth

    International Nuclear Information System (INIS)

    Sakai, Yasuhiko

    1980-01-01

    The radiation effects on growing bone were studied using immature rabbits. The irradiation was done with telecobalt to the right knee joint. The rabbits were divided into six groups according to the dose, such as 1,000, 2,000, 3,000, 4,000, 6,000 and 8,000 rad respectively. The effects of irradiation were investigated by RI-scintigraphy, X-ray photography and pathohistological examination. The following results were obtained. 1. In RI-scintigraphy using sup(99m)Tc-MDP, the change of accumulation ratio of the irradiated side was investigated. In terms of chronological observation, the accumulation ratio decreased most 5 weeks after irradiation and subsequently increased in the group irradiated with less than 4,000 rad. In the 6,000 rad group, the accumulation ratio decreased rapidly until 5 weeks after irradiation, and subsequently increased slightly. In the 8,000 rad group, the accumulation ratio progressively decreased unabated during the time observed. 2. X-ray findings of irradiated bones were as follows: In the group irradiated with more than 3,000 rad, sclerosis of the metaphysis and unclearness of the trabecula, thickening of the compact bone, bending, fissure and fracture of the bone appeared early with increased frequency with an increased in radiation doses. Also, according to an increase in radiation doses, growth inhibition in the length of the tibia was conspicuous. 3. In the histopathological findings, disturbances of the epiphyseal cartilage, the blood vessel system, trabecula, and medullary tissue becomes intense with increasing radiation doses. (author)

  6. NASA FACILITY FOR THE STUDY OF SPACE RADIATION EFFECTS

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, David R.

    1963-04-15

    Information on the energies andd fluxes of trapped electrons and protons in space is summarized, and the Space Radiation Effects Laboratory being constructed to simulate most of the space particulate-energy spectrum is described. A 600-Mev proton synchrocyclotron of variable energy and electron accelerators of 1 to 10 Mev will be included. The accelerator characteristics and the arrangement of the experimental and support buildings, particularly the beam facilities, are discussed; and the planned activities of the laboratory are given. (D.C.W.)

  7. Gamma radiation effect study in polycarbonate optical and mechanics properties

    International Nuclear Information System (INIS)

    Araujo, E.S. de.

    1991-02-01

    Polycarbonates (PC) are used in different industrial applications due to their excellent dielectric characteristics, impact resistance, and high temperature resistance. In some of these applications, the polycarbonates are exposed to gamma radiation which produces molecular scissions, causing changes in the polycarbonate properties. To estimate the radiation effects in the Durolon polycarbonate, samples were irradiated with 60 Co gamma rays with doses between 0,2 kGy and 300 kGy. The results obtained showed that the PC mechanical properties are not changed due to the gamma radiation. However the results showed an expressive variation in the yellowness index for doses above 1 kGy. The results showed that it is possible to use the gamma sterilization of PC in applications where the coloration of PC is not critical. (author). 21 refs, 25 figs, 3 tabs

  8. Use of medaka as a tool in studies of radiation effects and chemical carcinogenesis

    International Nuclear Information System (INIS)

    Hyodo-Taguchi, Y.; Aoki, K.; Matsudaira, H.

    1982-01-01

    The medaka, Oryzias latipes, a small freshwater oviparous fish, is common in Japan and found in some parts of Asia. Adult fish are 3.0-3.5 cm long and weigh 0.5-0.7 g. The small fish have been used extensively in this laboratory for analysis of radiation effects and for study of chemical carcinogenesis. These fish are relatively easy to rear and their reproductive biology is well known. Recently, inbred strains of the fish have been established by full sister-brother mating. In this report, we will review experimental results using medaka in studies of : 1) radiation effects on spermatogenesis, and 2) induction of hepatic tumors by MAM acetate, we will also review use of medaka in related studies of radiation effects and chemical carcinogenesis. (author)

  9. Study of ionizing radiation effect on human spermatozoa chromosomes

    International Nuclear Information System (INIS)

    Rousseaux, S.

    1990-02-01

    The purpose of this thesis is to study the radio-induced chromosomal aberrations in spermatozoa. After a brief recall on ionizing radiations, the author reviews the radio-induced chromosomal anomalies on somatic cells and on germinal line cells and spermatozoa. The author presents the technical aspects of human spermatozoa karyotype and finally studies the radio induced chromosomal anomalies of sperm to patients undergoing a radiotherapy. 13 tabs., 28 figs., 28 photos

  10. Studies of radiation effects on allopathic formulations for cancer management

    Energy Technology Data Exchange (ETDEWEB)

    Varshney, L; Choughule, S V; Dodke, P B; Jothish, P K [International Standard Orthopedic Measurements Education and Development (ISOMED), Bhabha Atomic Research Centre, Mumbai (India)

    2005-07-01

    In the present study, two anticancer drugs, Cyclophosphamide and Doxorubucin Hydrochloride have been investigated. The results of various physico-chemical tests on unirradiated and irradiated drugs indicate possibility of use of lower radiation doses and cryo-irradiation in case of sterilization of Cyclophosphamide. Doxorubcin Hydrochloride could be sterilized at 25 kGy without any significant changes in its physico-chemical properties. HPLC studies reveal formation of several trace level degradation products in irradiated cyclophosphamide. HPLC/MS studies revealed that higher and lower molecular weight products of the original molecules are formed on irradiation. Although, no significant changes are observed in absolute purity values, a little discolouration and formation of degradation products in Cyclophosphamide are the main impediments in acceptability of radiation sterilization. On the other hand, orange-red coloured Doxorubicin Hydrochloride did not show any such changes and could be radiation sterilized at normal sterilization dose of 25 kGy. (author)

  11. Studies of radiation effects on allopathic formulations for cancer management

    International Nuclear Information System (INIS)

    Varshney, L.; Choughule, S.V.; Dodke, P.B.; Jothish, P.K.

    2005-01-01

    In the present study, two anticancer drugs, Cyclophosphamide and Doxorubucin Hydrochloride have been investigated. The results of various physico-chemical tests on unirradiated and irradiated drugs indicate possibility of use of lower radiation doses and cryo-irradiation in case of sterilization of Cyclophosphamide. Doxorubcin Hydrochloride could be sterilized at 25 kGy without any significant changes in its physico-chemical properties. HPLC studies reveal formation of several trace level degradation products in irradiated cyclophosphamide. HPLC/MS studies revealed that higher and lower molecular weight products of the original molecules are formed on irradiation. Although, no significant changes are observed in absolute purity values, a little discolouration and formation of degradation products in Cyclophosphamide are the main impediments in acceptability of radiation sterilization. On the other hand, orange-red coloured Doxorubicin Hydrochloride did not show any such changes and could be radiation sterilized at normal sterilization dose of 25 kGy. (author)

  12. Study of neutron radiation effects on MOS structures

    International Nuclear Information System (INIS)

    Vaidya, Sangeeta J.

    2003-01-01

    We have studied charge trapping in the oxide and generation of interface states due to neutrons. It is observed that neutrons, though uncharged, are capable of causing ionization and interface damage and it is significant under biased irradiation conditions. One of the important features of this work is that neutron irradiation was carried out in a nuclear reactor (swimming pool type) itself in contrast to the earlier reported work which used separate neutron sources for similar studies. To simulate real life situations, all our devices were biased during irradiation. In our belief, both of these facts gave credence to our observed experimental results. (author)

  13. Fundamental radiation effects studies in the fusion-materials program

    International Nuclear Information System (INIS)

    Doran, D.G.

    1981-10-01

    Some examples of progress being made in DAFS studies are given. The primary parameters in which most damage models are expressed are total displacements per atom (dpa), total helium concentration (appm), and the helium-to-dpa ratio. The concentrations of other transmutation products than helium have assumed significance in certain cases as will be seen below. The number of dpa is generally taken proportional to the damage energy, the total energy deposited in a material, corrected for the fraction dissipated in electronic excitation and ionization

  14. Study of the radiation effect in breast implants

    Energy Technology Data Exchange (ETDEWEB)

    Moreno T, L. R.; Ramirez R, A., E-mail: lumor2000@yahoo.com.mx [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Departamento de Ciencias Basicas, Av. San Pablo No. 180, Col. Reynosa Tamaulipas, 02200 Mexico D. F. (Mexico)

    2013-10-01

    This breast cancer is one of the most important death causes in women. Among the more frequently medical treatment for advanced breast cancer is the mastectomy. This situation leads to silicone implants as an esthetic option. There have been cases in patients with implants where cancer was frequently detected, in which a conventional radiotherapy is required. In this work is presented a study of the probable adverse effects caused by the application of high power X-rays (6-10 MV) to the silicone implants and to the surrounding tissues. In the research carried out at the clinic, none Bolus effect was detected in patients with implants. Our results prescribe that in the case of patients with implants and frequent breast cancer, the removal of implants is not necessary due radiotherapy works directly in the damaged tissues. (Author)

  15. Study of the radiation effect in breast implants

    International Nuclear Information System (INIS)

    Moreno T, L. R.; Ramirez R, A.

    2013-01-01

    This breast cancer is one of the most important death causes in women. Among the more frequently medical treatment for advanced breast cancer is the mastectomy. This situation leads to silicone implants as an esthetic option. There have been cases in patients with implants where cancer was frequently detected, in which a conventional radiotherapy is required. In this work is presented a study of the probable adverse effects caused by the application of high power X-rays (6-10 MV) to the silicone implants and to the surrounding tissues. In the research carried out at the clinic, none Bolus effect was detected in patients with implants. Our results prescribe that in the case of patients with implants and frequent breast cancer, the removal of implants is not necessary due radiotherapy works directly in the damaged tissues. (Author)

  16. Molecular dynamics studies of radiation effects in silicon carbide

    International Nuclear Information System (INIS)

    Diaz de la Rubia, T.; Caturla, M.J.; Tobin, M.

    1995-01-01

    We discuss results of molecular dynamics computer simulation studies of 3 keV and 5 keV displacement cascades in β-SIC, and compare them to results of 5 keV cascades in pure silicon. The SiC simulations are performed with the Tersoff potential. For silicon we use the Stillinger-Weber potential. Simulations were carried out for Si recoils in 3 dimensional cubic computational cells With periodic boundary conditions and up to 175,616 atoms. The cascade lifetime in SiC is found to be extremely short. This, combined with the high melting temperature of SiC, precludes direct lattice amorphization during the cascade. Although large disordered regions result, these retain their basic crystalline structure. These results are in contrast with observations in pure silicon where direct-impact amorphization from the cascade is seen to take place. The SiC results also show anisotropy in the number of Si and C recoils as well as in the number of replacements in each sublattice. Details of the damage configurations obtained will be discussed

  17. Characteristics of rotating target neutron source and its use in radiation effects studies

    International Nuclear Information System (INIS)

    Van Konynenburg, R.A.; Barschall, H.H.; Booth, R.; Wong, C.

    1975-07-01

    The Rotating Target Neutron Source (RTNS) at Lawrence Livermore Laboratory is currently the most intense source of DT fusion neutrons available for the study of radiation effects in materials. This paper will present a brief description of the machine, outline the history of its development and discuss its performance characteristics and its application to CTR materials research. (U.S.)

  18. X radiation effects on the wound healing process after tooth extraction. Histological study in rats

    International Nuclear Information System (INIS)

    Miguel, R.M.; Santos Pinto, R. dos; Okamoto, T.; Santos Pinto, M.C. dos

    1988-01-01

    The X radiation effects on the wound healing process after teeth extractions are studied histologically. Albino rats are employed. After their right upper incisors were extracted, they were divided into groups of 20 animals each. With exception of the group I (control), 24 hours after teeth extractions the groups II, III and IV received X radiation, respectively, in the dosage of 75,125 and 175 R. The rats were sacrificed in group of 4, at 3, 6, 9,15 and 21 postoperative days and a histological study is done. (M.A.C.) [pt

  19. Studies of radiation effects on the indicator of behavior and learning of the nematode caenorhabditis elegans

    International Nuclear Information System (INIS)

    Sakashita, Tetsuya; Suzuki, Michiyo

    2011-01-01

    Radiation effects on the essential behavior and its higher level of learning are described mainly on authors' studies of the title nematode (N), a unique model of which, in a whole, genome is mapped, genealogy of cells is defined, and anatomical distribution and linkage of nervous cells are known. N exhibits various behaviors such as meandering on the culture agar/swimming in water responding to given stimuli like touch, temperature, and chemical. Authors have found that the locomotive activity of N is reduced by gamma-irradiation. Their subsequent irradiation study of 60 Co gamma ray at 300-900 Gy (32 Gy/sec) to wild type and cat-2 mutant lacking tyrosine hydroxylase in the presence/absence of N's food has revealed that dopaminergic nerves do not participate in the mechanism of the reduction unexpectedly. Rather, participation of an active oxygen species is suggested by their following study with H 2 O 2 , but exact nervous system responsible to the reduction is still to be elucidated in future. For radiation effect on N's associative learning, authors have used the reversal of salt preference, where Ns cultured on NaCl-containing agar covered by E. coli (food), being chemotactic to the salt, are conditioned by food removal: salt preference is reversed after learning. The gamma ray irradiation at the conditioning stage but neither before nor after learning, is found to lead to reduction of the chemotaxis (promotion of learning), and this radiation response is found to occur in N lacking gpc-1 gene coding G-protein gamma-subunit which is localized in a part of sensory nerves. Authors think this radiation effect is a modulation of nervous circuit for chemotaxis of N, but of which relation with the complicated nervous functions in higher animals is further to be elucidated in aspects of learning and memory. (T.T.)

  20. View of environmental radiation effects from the study of radiation biology in C. elegans

    International Nuclear Information System (INIS)

    Sakashita, Tetsuya

    2011-01-01

    Caenorhabditis (C.) elegans is a non-parasitic soil nematode and is well-known as a unique model organism, because of its complete cell-lineage, nervous network and genome sequences. Also, C. elegans can be easily manipulated in the laboratory. These advantages make C. elegans as a good in vivo model system in the field of radiation biology. Radiation effects in C. elegans have been studied for three decades. Here, I briefly review the current knowledge of the biological effects of ionizing irradiation in C. elegans with a scope of environmental radiation effects. Firstly, basic information of C. elegans as a model organism is described. Secondly, historical view is reported on the study of radiation biology in C. elegans. Thirdly, our research on learning behavior is presented. Finally, an opinion of the use of C. elegans for environmental radiation protection is referred. I believe that C. elegans may be a good promising in vivo model system in the field of environmental radiation biology. (author)

  1. Activities of the National Academy of Sciences in relation to the Radiation Effects Research Foundation

    Energy Technology Data Exchange (ETDEWEB)

    Edington, C.W.

    1992-06-01

    This progress report relates progress in the various research projects evaluating the late health effects, both somatic and genetic, resulting from radiation exposure of the survivors of the atomic bombs at Hiroshima and Nagasaki, Japan. Considerable progress has been made in the collection and utilization of the various epidemiological data bases. These include the Life Span Study, (LSS) cohort, the Adult Health Study (AHS) cohort, the In Utero cohort, the leukemia registry and the F-1 Study population. Important progress has been made in using RERF Tumor and Tissue Registry records for evaluation of cancer incidence and radiation risk estimates for comparison with cancer mortality and risk in the LSS cohort. At the present time, a manuscript on the incidence of solid tumors (1950-1987) is undergoing internal and external review for publication as an RERF Technical report (TR) and for publication in a peer-reviewed scientific journal. In addition, manuscripts are in preparation on (1) a comprehensive report on the incidence of hematological cancers, including analysis of leukemia by cell type (1950-1987), (2) a general description of Tumor Registry operations and (3) a comparison of incidence- and mortality-based estimates of radiation risk in the LSS cohort.

  2. Study on radiation effect of poly (vinyl alcohol) films irradiated by tritium decay

    International Nuclear Information System (INIS)

    Li Hairong; Peng Shuming; Zhou Xiaosong; Yu Mingming; Xia Lidong; Chen Xiaohua; Liang Jianhua

    2014-01-01

    The radiation effect of poly(vinyl alcohol) films used as a kind of gas-barrier material for inertial confinement fusion (ICF) targets was studied under the different conditions of β-ray from tritium decay. The changes of physical and chemical properties of the irradiated material samples were analyzed by FTIR, XRD and AFM. The tritium-hydrogen isotopic exchange reaction of the irradiated samples mainly occurs at C-H bond and the IR absorption peak of C-T bond obviously increases with the irradiation dose. For strong hydrogen bonding interaction, the isotopic exchange reaction doesn't occur at O-H bond. The crystallinity degree and surface morphology of the irradiated samples were changed. The tensile properties of irradiated poly(vinyl alcohol) films were measured by universal material testing machine. The results show that the change trend of mechanical properties is in accordance with the microstructures of the irradiated samples. (authors)

  3. Study on aerosol optical properties and radiative effect in cloudy weather in the Guangzhou region

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Tao, E-mail: tdeng@grmc.gov.cn [Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction, China Meteorological Administration, Guangzhou 510080 (China); Deng, XueJiao; Li, Fei [Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction, China Meteorological Administration, Guangzhou 510080 (China); Wang, ShiQiang [Zhuhai Meteorological Administration, Zhuhai 519000 (China); Wang, Gang [Haizhu Meteorological Administration, Guangzhou, 510000 (China)

    2016-10-15

    Currently, Guangzhou region was facing the problem of severe air pollution. Large amount of aerosols in the polluted air dramatically attenuated solar radiation. This study investigated the vertical optical properties of aerosols and inverted the height of boundary layer in the Guangzhou region using the lidar. Simultaneously, evaluated the impact of different types of clouds on aerosol radiation effects using the SBDART. The results showed that the height of the boundary layer and the surface visibility changed consistently, the average height of the boundary layer on the hazy days was only 61% of that on clear days. At the height of 2 km or lower, the aerosol extinction coefficient profile distribution decreased linearly along with height on clear days, but the haze days saw an exponential decrease. When there was haze, the changing of heating rate of atmosphere caused by the aerosol decreased from 3.72 K/d to 0.9 K/d below the height of 2 km, and the attenuation of net radiation flux at the ground surface was 97.7 W/m{sup 2}, and the attenuation amplitude was 11.4%; when there were high clouds, the attenuation was 125.2 W/m{sup 2} and the attenuation amplitude was 14.6%; where there were medium cloud, the attenuation was 286.4 W/m{sup 2} and the attenuation amplitude was 33.4%. Aerosol affected mainly shortwave radiation, and affected long wave radiation very slightly. - Highlights: • Large amount of aerosols dramatically attenuated solar radiation in Guangzhou region. • Investigated the aerosol extinction coefficient profile distribution and inverted the height of boundary layer using the lidar • Evaluated the impact of different types of clouds on aerosol radiation effects.

  4. DOE life-span radiation effects studies at Pacific Northwest Laboratory

    International Nuclear Information System (INIS)

    Thompson, R.C.; Cross, F.T.; Dagle, G.E.; Park, J.F.; Sanders, C.L.

    1986-01-01

    Major life-span radiation effects studies at Pacific Northwest Laboratory fall into three categories: (1) studies with beagle dogs exposed to plutonium compounds via a single inhalation; (2) studies with dogs and rats exposed chronically via inhalation to various combinations and concentrations of radon, radon daughters, and other components of uranium mine atmospheres; and (3) a study in which rats are exposed via single inhalation, in very large numbers, to very low concentrations of 239 PuO 2 . Exposure of beagles currently on study was initiated in 1970 with 239 PuO 2 , in 1973 with 238 PuO 2 , and in 1976 with 239 Pu(NO 3 ) 4 . These experiments involve more than 500 animals, many of them still alive. Experiments seeking to explain the increased incidence of lung cancer in uranium miners have been in progress since 1966. Present emphasis is on studies with rats, in an attempt to define dose-effect relationships at the lowest feasible radon-daughter exposure levels. Our very-low-level experiment with inhaled 239 PuO 2 in rats, with exposures still under way, includes 1000 rats in the control group and 1000 rats in the lowest-exposure group, where life-span lung doses of <5 rads are anticipated

  5. Radiation effects on cancer risks in the life span study cohort

    International Nuclear Information System (INIS)

    Kodama, K.; Ozasa, K.; Katayama, H.; Shore, R. E.; Okubo, T.

    2012-01-01

    To determine late health effects of radiation in atomic bomb survivors, the Radiation Effects Research Foundation has been conducting studies on the Life Span Study (LSS) population, which consists of 93 000 atomic bomb survivors and 27.000 controls. A recent report on the incidence of solid cancers estimates that at the age of 70 y, after exposure at the age of 30 y, solid-cancer rates increase by about 35 % per Gy for men and 58 % per Gy for women. The age-at-exposure is an important risk modifier. Furthermore, it seems that radiation-associated increases in cancer rates persist throughout life. In addition, radiation has similar effects upon first-primary and second-primary cancer risks. A recent report on leukemia mortality suggested that the effect of radiation on leukemia mortality persisted for more than five decades. In addition, a significant dose-response for myelodysplastic syndrome is found in Nagasaki LSS members 40-60 y after radiation exposure. In view of the nature of the continuing increase in solid cancers, the LSS should continue to provide important new information on cancer risks, as most survivors still alive today were exposed to the atomic bomb radiation under the age of 20 y and are now entering their cancer-prone years. (authors)

  6. Numerical Study on Radiation Effects to Evaporator in Natural Vacuum Solar Desalination System

    Science.gov (United States)

    Siregar, R. E. T.; Ronowikarto, A. D.; Setyawan, E. Y.; Ambarita, H.

    2018-01-01

    The need for clean water is increasing day by day due to the increasing factor of living standard of mankind, hence designed natural vacuum solar desalination. The natural vacuum Solar desalination is studied experimentally. A small-scale natural vacuum desalination study consists of evaporator and condenser as the main components designed and manufactured. To transfer heat from the solar collector into the evaporator, the fluid transfer system uses a pump powered by a solar cell. Thus, solar collectors are called hybrid solar collectors. The main purpose of this exposure is to know the characteristics of the radiation effects on incoming energy on the evaporator during the process. This system is tested by exposing the unit to the solar radiation in the 4th floor building in Medan. The experiment was conducted from 8.00 to 16.00 local time. The results show that natural vacuum solar desalination with hybrid solar collectors can be operated perfectly. If the received radiation is high, then the incoming energy received by the evaporator will also be high. From measurements with HOBO microstation, obtained the highest radiation 695.6 W/m2, and the calculation result of incoming energy received evaporator obtained highest result 1807.293 W.

  7. Cancer risk among atomic bomb survivors. The RERF Life Span Study. Radiation Effects Research Foundation

    International Nuclear Information System (INIS)

    Shimizu, Y.; Schull, W.J.; Kato, H.

    1990-01-01

    This article summarizes the risk of cancer among the survivors of the atomic bombing of Hiroshima and Nagasaki. We focus primarily on the risk of death from cancer among individuals in the Life Span Study sample of the Radiation Effects Research Foundation from 1950 through 1985 based on recently revised dosimetry procedures. We report the risk of cancer other than leukemia among the atomic bomb survivors. We note that the number of excess deaths of radiation-induced malignant tumors other than leukemia increases with age. Survivors who were exposed in the first or second decade of life have just entered the cancer-prone age and have so far exhibited a high relative risk in association with radiation dose. Whether the elevated risk will continue or will fall with time is not yet clear, although some evidence suggests that the risk may be declining. It is important to continue long-term follow-up of this cohort to document the changes with time since exposure and to provide direct rather than projected risks over the lifetime of an exposed individual

  8. A new sensitive technique for study of radiation effects in amino acids

    International Nuclear Information System (INIS)

    Thwaites, D.I.; Buchan, G.; Ettinger, K.V.; Mallard, J.R.; Takavar, A.

    1976-01-01

    A new technique for the study of radiation induced free radicals in amino acids based on their reactions when untrapped by dissolution in water is reported. The light emission or lyoluminescence response of various amino acids to gamma radiation ( 60 Co) measured 4 hr after irradiation are shown. The sensitivities vary over three orders of magnitude, but there is little or no correlation between the lyoluminescent response and the structural type of amino acid. Dose-reponse curves indicate that the useful range extends from a few krad to a few hundred krad. Methods of extending the lower limits are discussed. Storage of irradiated material over a period of 4 months at 20 0 C showed changes of the order of 10%. Exposure to daylight has no effect on the light yield of amino acids. It is stated that the lyoluminescence technique is more sensitive than ESR in detecting radiation effects in amino acids. Lyoluminescence of irradiated proteins, RNA and DNA, has been observed. It appears that the new method may be particularly useful in providing information on the nature and magnitude of direct radiation damage in biologically important compounds and find applications in radiation dosimetry. (U.K.)

  9. Radiosensitivity study and radiation effects on morphology characterization of grey oyster mushroom Pleurotus sajor-caju

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Rosnani Abdul; Awang, Mat Rasol; Mohamad, Azhar; Mutaat, Hassan Hamdani; Maskom, Mohd Meswan [Bioprocess Group, Agrotechnology and Biosciences Division, Malaysian Nuclear Agency, Bangi 43600, Selangor (Malaysia); Daud, Fauzi; Senafi, Sahidan [School of Bioscience and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor (Malaysia)

    2014-09-03

    Radiosensitive dosage and morphology characterization of irradiated grey oyster mushroom Pleurotus sajor-caju by gamma rays was investigated due to effects of irradiation. In order to establish the effect, mycelium of P. sajor-caju was irradiated by gamma rays at dose 0.1 to 8.0 kGy with dose rate 0.227 Gy sec{sup −1}. The irradiation of mycelia was carried out at the radiation facility in Malaysian Nuclear Agency. The radiosensitivity study was performed by evaluating the percentage of survival irradiated mycelia. The lethal dose of the mycelium P. sajor-caju was determined at 4.0 kGy and LD{sub 50} to be equal at 2.2 kGy. The radiation effects on morphology were evaluated based on growth rate of irradiated mycelia, mycelia types, colonization period on substrate, morphology of fruit bodies and yields. The results shown growth rate of irradiated mycelium was slightly lower than the control and decreased as the dose increased. Irradiation was found can induced the primordia formation on PDA and the BE of irradiated seed is higher than to control. The irradiation is proven to be useful for generating new varieties of mushroom with commercial value to the industry.

  10. Applications of advanced electron microscopy techniques to the studies of radiation effects in ceramic materials

    International Nuclear Information System (INIS)

    Wang, L.M.

    1998-01-01

    This paper summarizes some recent results from the application of several advanced transmission electron microscopy (TEM) techniques to the studies of radiation effects in insulators with the main focus on radiation-induced amorphization. These techniques include in situ TEM during ion-beam irradiation at cryogenic and elevated temperatures, cross-sectional TEM, high-resolution TEM, and image simulation on partially damaged materials, as well as digital TEM with image processing and analysis. The combination of these techniques may often provide very detailed information about the microstructure evolution during energetic particle irradiation, especially at the early stages, which is unobtainable with any other analytical methods. These techniques have been successfully applied to the analysis of a large group of ion-beam-irradiated ceramics, including quartz, silicon carbides, uranium oxide, apatite, spinel and other complex mineral phases. The advantages and limitations of each technique, as well as some important technical details for the analysis of radiation damage in ceramics are presented. (orig.)

  11. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES

    Directory of Open Access Journals (Sweden)

    R. A. Zaveri

    2012-08-01

    Full Text Available Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE Atmospheric Radiation Measurement (ARM program's Carbonaceous Aerosol and Radiative Effects Study (CARES carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites – one within the Sacramento urban area and another about 40 km to the northeast in the foothills area – were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and "aged" urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: (a the scientific background and motivation for the study, (b the operational and logistical information pertinent to the execution of the study, (c an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and (d a roadmap

  12. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)

    Energy Technology Data Exchange (ETDEWEB)

    Zaveri, R. A.; Shaw, W. J.; Cziczo, D. J.; Schmid, B.; Ferrare, R. A.; Alexander, M. L.; Alexandrov, M.; Alvarez, R. J.; Arnott, W. P.; Atkinson, D. B.; Baidar, S.; Banta, R. M.; Barnard, J. C.; Beranek, J.; Berg, L. K.; Brechtel, F.; Brewer, W. A.; Cahill, J. F.; Cairns, B.; Cappa, C. D.; Chand, D.; China, S.; Comstock, J. M.; Dubey, M. K.; Easter, R. C.; Erickson, M. H.; Fast, J. D.; Floerchinger, C.; Flowers, B. A.; Fortner, E.; Gaffney, J. S.; Gilles, M. K.; Gorkowski, K.; Gustafson, W. I.; Gyawali, M.; Hair, J.; Hardesty, R. M.; Harworth, J. W.; Herndon, S.; Hiranuma, N.; Hostetler, C.; Hubbe, J. M.; Jayne, J. T.; Jeong, H.; Jobson, B. T.; Kassianov, E. I.; Kleinman, L. I.; Kluzek, C.; Knighton, B.; Kolesar, K. R.; Kuang, C.; Kubátová, A.; Langford, A. O.; Laskin, A.; Laulainen, N.; Marchbanks, R. D.; Mazzoleni, C.; Mei, F.; Moffet, R. C.; Nelson, D.; Obland, M. D.; Oetjen, H.; Onasch, T. B.; Ortega, I.; Ottaviani, M.; Pekour, M.; Prather, K. A.; Radney, J. G.; Rogers, R. R.; Sandberg, S. P.; Sedlacek, A.; Senff, C. J.; Senum, G.; Setyan, A.; Shilling, J. E.; Shrivastava, M.; Song, C.; Springston, S. R.; Subramanian, R.; Suski, K.; Tomlinson, J.; Volkamer, R.; Wallace, H. W.; Wang, J.; Weickmann, A. M.; Worsnop, D. R.; Yu, X. -Y.; Zelenyuk, A.; Zhang, Q.

    2012-01-01

    Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program’s Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites – one within the Sacramento urban area and another about 40 km to the northeast in the foothills area – were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and “aged” urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: a) the scientific background and motivation for the study, b) the operational and logistical information pertinent to the execution of the study, c) an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and d) a roadmap of

  13. Study on ionizing radiation effects in diesel and crude oil: organic compounds, hydrocarbon, sulfur and nitrogen

    International Nuclear Information System (INIS)

    Andrade, Luana dos Santos

    2014-01-01

    Petroleum is the most important energy and pollution source in the world, nowadays. New technologies in petrochemical industry aim to minimize energy spending at the process and to reduce pollution products. Sulfur and nitrogen compounds generate environmental problems; the most relevant is air pollution that affects the population health directly. The nuclear technology has been used in environmental protection through pollutants removal by free radicals produced at action of the radiation in water molecule. The objective of this study is to evaluate the radiation effects on oil and diesel, mainly in the hydrocarbons, organic sulfur, and nitrogen compounds. It was studied a molecule model of sulfur, named benzothiophene, diesel and crude oil samples. The samples were irradiated using a Co-60 source, Gammacell type. The total sulfur concentration in the samples was determined by X-ray fluorescence spectrometry, and organic compounds were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The study of molecular model showed that 95% was degraded at 20 kGy dose rate. Irradiation at 15 kGy of absorbed dose showed some cracking in petrol hydrocarbons, however with higher doses it was observed polymerization and low efficiency of cracking. It was observed that the sulfur compounds from diesel and petroleum was efficiently reduced. The applied doses of 15 kGy and 30 kGy were the most efficient on desulfurization of petroleum, and for diesel the highest variation was observed with 30 kGy and 50 kGy of absorbed dose. The distillation and chromatographic separation using an open column with palladium chloride as stationary phase showed a preferential separation of organic sulfur compounds in petroleum. (author)

  14. Ionizing radiation effect study by electron beam on acrylonitrile butadiene styrene - ABS terpolymer

    International Nuclear Information System (INIS)

    Landi, Tania Regina Lourenco

    2003-01-01

    The great advantage in the researches involving development has as objective to increase significantly the quality of the products. The ABS (acrylonitrile, butadiene, styrene) resins are terpolymers formed by an elastomer and two thermoplastics amorphous components. The three different monomeric units from the terpolymer ABS contribute separately to the material characteristics exhibited. The molecular stiffness originating from polystyrene and the benzene ring hanging on the chain is responsible for the flexion module ABS. The acrylonitrile and the styrene incorporated butadiene exercises strong influence in the resistance to the impact because it reduces the bonding among them. The engineering use of this terpolymer became important due their mechanical properties and mainly, for the responses of this to tensions or deformations applied. The polymeric materials, when submitted to the ionizing radiation are modified by the transference of energy to these materials, introducing excitation and ionization of the molecules, generating chemical reactions that can produce permanent modifications in the polymeric physicochemical structure. The induced modifications can result in the polymeric material degradation or crosslinking, which can result in the improvement of some properties. This work has, as objective, to study the electron beam ionizing radiation effect, at different doses, in the properties of the polymer ABS. The studied properties were: tensile strength at break, elongation at break, Izod impact strength, flexural strength, melt flow index, Vicat softening temperature and the thermic distortion temperature. Also researches on Differential Scanning Calorimetry (DSC) and Thermogravimetric Analyses (TGA) were accomplished. From the experimental results, it was showed that for doses until 500 kGy, at 22.6 kGy/s dose rate, in the presence of air, the crosslinking process of ABS prevails. (author)

  15. Radiation effects in gases

    International Nuclear Information System (INIS)

    Leonhardt, J.W.

    1985-01-01

    Problems in the studies of radiation effects in gases are discussed. By means of ionization- excitation- and electron-capture yields various applications are characterized: ionization detectors, X-ray detectors, radionuclide battery, and radiation-induced chemical gas-phase reactions. Some new results of basic research in respect to the SO 2 oxidation are discussed. (author)

  16. A Global Modeling Study on Carbonaceous Aerosol Microphysical Characteristics and Radiative Effects

    Science.gov (United States)

    Bauer, S. E.; Menon, S.; Koch, D.; Bond, T. C.; Tsigaridis, K.

    2010-01-01

    Recently, attention has been drawn towards black carbon aerosols as a short-term climate warming mitigation candidate. However the global and regional impacts of the direct, indirect and semi-direct aerosol effects are highly uncertain, due to the complex nature of aerosol evolution and the way that mixed, aged aerosols interact with clouds and radiation. A detailed aerosol microphysical scheme, MATRIX, embedded within the GISS climate model is used in this study to present a quantitative assessment of the impact of microphysical processes involving black carbon, such as emission size distributions and optical properties on aerosol cloud activation and radiative effects. Our best estimate for net direct and indirect aerosol radiative flux change between 1750 and 2000 is -0.56 W/m2. However, the direct and indirect aerosol effects are quite sensitive to the black and organic carbon size distribution and consequential mixing state. The net radiative flux change can vary between -0.32 to -0.75 W/m2 depending on these carbonaceous particle properties at emission. Taking into account internally mixed black carbon particles let us simulate correct aerosol absorption. Absorption of black carbon aerosols is amplified by sulfate and nitrate coatings and, even more strongly, by organic coatings. Black carbon mitigation scenarios generally showed reduced radiative fluxeswhen sources with a large proportion of black carbon, such as diesel, are reduced; however reducing sources with a larger organic carbon component as well, such as bio-fuels, does not necessarily lead to a reduction in positive radiative flux.

  17. Radiation effects and metalloproteins studied by x-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wurzbach, J.A.

    1975-07-01

    X-ray photoelectron spectroscopy (XPS) is used to study the bonding structure at the iron site of cytochrome c and the bonding of rare earth ions to the phosphate oxygens of ATP. Radiation effects are studied on several amino acid and simple peptide model systems. The emission spectrum of the x-ray source is calculated from literature references. The distributions of photon energy as a function of photon frequency and as a function of take-off angle are obtained. From these distributions, the radiation dose absorbed by an organic sample is found to be 10/sup 6/ rads/sec. The C 1s and N 1s spectra of amino acids and peptides are studied to characterize an internal reference standard for protein XPS spectra. Samples of native cytochrome c prepared from solutions of pH 1.5, 3, 7, and 11 are studied. Control samples include porphyrin cytochrome c (PCC), the metal free analogue of the native protein, and microperoxidase (MP), a mixture of heme peptides derived from the peptic digestion of cytochrome c. These samples show two S 2p peaks. The first peak has a binding energy (BE) of 163 eV, which corresponds to the S containing amino acids; the second peak is shifted to 167 eV. This large shift may be the result of Fe-S binding, or oxidation, or both. Low spin ferricytochrome c and ferri-MP were found to have Fe 3p BE's that are unusually low (51 eV) compared to other ferric compounds (54 to 58 eV) and even Fe metal (53 eV). X-ray crystal structures of these compounds show that low spin heme Fe lies in the porphyrin plane; while, high spin heme Fe is displaced above the plane. The N 1s and P 2p spectra of ATP show no change except slight broadening when Nd/sup 3 +/ is substituted for Na/sup +/. Thus, there is no inconsistency with proposals that rare earth ions might be useful as substitutes for alkali metal ions and alkaline earth ions in proteins.

  18. Radiation effects and metalloproteins studied by x-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Wurzbach, J.A.

    1975-07-01

    X-ray photoelectron spectroscopy (XPS) is used to study the bonding structure at the iron site of cytochrome c and the bonding of rare earth ions to the phosphate oxygens of ATP. Radiation effects are studied on several amino acid and simple peptide model systems. The emission spectrum of the x-ray source is calculated from literature references. The distributions of photon energy as a function of photon frequency and as a function of take-off angle are obtained. From these distributions, the radiation dose absorbed by an organic sample is found to be 10 6 rads/sec. The C 1s and N 1s spectra of amino acids and peptides are studied to characterize an internal reference standard for protein XPS spectra. Samples of native cytochrome c prepared from solutions of pH 1.5, 3, 7, and 11 are studied. Control samples include porphyrin cytochrome c (PCC), the metal free analogue of the native protein, and microperoxidase (MP), a mixture of heme peptides derived from the peptic digestion of cytochrome c. These samples show two S 2p peaks. The first peak has a binding energy (BE) of 163 eV, which corresponds to the S containing amino acids; the second peak is shifted to 167 eV. This large shift may be the result of Fe-S binding, or oxidation, or both. Low spin ferricytochrome c and ferri-MP were found to have Fe 3p BE's that are unusually low (51 eV) compared to other ferric compounds (54 to 58 eV) and even Fe metal (53 eV). X-ray crystal structures of these compounds show that low spin heme Fe lies in the porphyrin plane; while, high spin heme Fe is displaced above the plane. The N 1s and P 2p spectra of ATP show no change except slight broadening when Nd 3+ is substituted for Na + . Thus, there is no inconsistency with proposals that rare earth ions might be useful as substitutes for alkali metal ions and alkaline earth ions in proteins

  19. Study on the radiation preservation of apples and the radiation effects

    International Nuclear Information System (INIS)

    Zhao Kejian; Lu Dunzhu; Wan Hong; Zhu Zhaonan; Xu Shanmei

    1987-01-01

    The radiation effects on respiration and ethylene production in apple and its radiation preservation were reported in this paper. It shows that, when irradiation was applied immediately after harvest, the respiratory rate and ethylene production increase with the increasing of irradiation dose. When irradiation was applied after 7-10 days of storage, the respiratory rate still rises with the dose, while there is a decrease in ethylene production with the increasing of dose. If the irradiation dose is less than 800 Gy the rise of respiratory rate of irraadiated apple returns to the level of the control within 5 days, but ethylene production of irradiated apple keeps a lower level. According to the above results, dose of 300-500 Gy may be recommended for radiation preseration of apple. Ascorbic acid is unstable and sensitive to radiation. The radiation effects on ascorbic acid in apple is very small because the saccharides and some organic acid in apple, especially malic acid, are able to protect ascorbic acid from radiation damage. From measuring the saccharides and acids in apple, it is obvious that there is no significant difference between irradiated and non-irradiated apple. Long-life free radical in apple was not detected after irradiation. The scald of apple is reduced from 60% to less than 15% after cold storage for 8 monthes. The taste results indicated, tasting them without knowing which is irradiated or not, that the irradiated apple is superior to controlled sample

  20. Study on the radiation effect of polyether-urethane in the γ radiation field

    International Nuclear Information System (INIS)

    Huang, W.; Xu, Y.S.; Chen, X.J.; Gao, X.L.; Tang, Y.M.; Wang, H.Y.

    2005-01-01

    Polyether-urethane (ETPU) is made up of hard and soft sections. The hard section which is mainly in crystalline state is carbamate, and soft section which is in amorphous state is polyether. Reference reports in detail the degradation of polyurethane deduced by thermal oxidation. The result shows that the thermal degradation begins with the caramate group. The polyalcohol is the weak point of polyurethane degradation in the presence of oxygen. Similarly, the anti-radiation of carbamate (hard section) is superior to that of polyether (soft section) In our former work, we have discussed the degradation of ETPU foam deduced by electron beam. And we have studied the composition and yields of gas products from the radiation degradation, and the changes of the thermal property, micro-phase separation and the microscopic form of irradiated samples. In this article, the radiation effect of γ-ray on polyether-urethane foam was studied. The gas products from irradiated samples were analyzed quantitatively and qualitatively by gas chromatography. Compared with the standard gas, the gas products are H 2 , CO 2 , CH 4 , C 2 H 6 and so on. Among these gases, the gas yield of CO 2 is the most, that of H 2 is less, and those of CH 4 and C 2 H 6 are the least. The yields of different sorts of gases increase with the dose raising. Furthermore, the radiation degradation of the sample is the most serious in the oxygen atmosphere, less in air, and the least in vacuum. ESR of ETPU sample irradiated by γ ray in vacuum is shown in figurel, which is determined at the room temperature, and ESR of polyester-urethane (ESPU) irradiated by UV light is shown in figure 2. It can be seen from these two figures that the spectral shape is different. The radical peak in the sample irradiated by UV light is symmetrical, which indicates that there is only one sort of radical; but that is not the truth to the sample irradiated by gamma ray for its asymmetrical radical peak. According to the results of

  1. Biological radiation effects

    International Nuclear Information System (INIS)

    Gomes, R.A.

    1976-01-01

    The stages of processes leading to radiation damage are studied, as well as, the direct and indirect mechanics of its production. The radiation effects on nucleic acid and protein macro moleculas are treated. The physical and chemical factors that modify radiosensibility are analysed, in particular the oxygen effects, the sensibilization by analogues of nitrogen bases, post-effects, chemical protection and inherent cell factors. Consideration is given to restoration processes by excision of injured fragments, the bloching of the excision restoration processes, the restoration of lesions caused by ionizing radiations and to the restoration by genetic recombination. Referring to somatic effects of radiation, the early ones and the acute syndrome of radiation are discussed. The difference of radiosensibility observed in mammalian cells and main observable alterations in tissues and organs are commented. Referring to delayed radiation effects, carcinogeneses, alterations of life span, effects on growth and development, as well as localized effects, are also discussed [pt

  2. Kinetic theory of radiation effects

    International Nuclear Information System (INIS)

    Mansur, L.K.

    1987-01-01

    To help achieve the quantitative and mechanistic understanding of these processes, the kinetic theory of radiation effects has been developed in the DOE basic energy sciences radiation effects and fusion reactor materials programs, as well as in corresponding efforts in other countries. This discipline grapples with a very wide range of phenomena and draws on numerous sub-fields of theory such as defect physics, diffusion, elasticity, chemical reaction rates, phase transformations and thermodynamics. The theory is cast in a mathematical framework of continuum dynamics. Issues particularly relevant to the present inquiry can be viewed from the standpoints of applications of the theory and areas requiring further progress

  3. Study on ionizing radiation effects of bipolar transistor with BPSG films

    International Nuclear Information System (INIS)

    Lu Man; Zhang Xiaoling; Xie Xuesong; Sun Jiangchao; Wang Pengpeng; Lu Changzhi; Zhang Yanxiu

    2013-01-01

    Background: Because of the damage induced by ionizing radiation, bipolar transistors in integrated voltage regulator could induce the current gain degradation and increase leakage current. This will bring serious problems to electronic system. Purpose: In order to ensure the reliability of the device work in the radiation environments, the device irradiation reinforcement technology is used. Methods: The characteristics of 60 Co γ irradiation and annealing at different temperatures in bipolar transistors and voltage regulators (JW117) with different passive films for SiO 2 +BPSG+SiO 2 and SiO 2 +SiN have been investigated. Results: The devices with BPSG film enhanced radiation tolerance significantly. Because BPSG films have better absorption for Na + in SiO 2 layer, the surface recombination rate of base region in a bipolar transistor and the excess base current have been reduced. It may be the main reason for BJT with BPSG film having a good radiation hardness. And annealing experiments at different temperatures after irradiation ensure the reliability of the devices with BPSG films. Conclusions: A method of improving the ionizing irradiation hardness of bipolar transistors is proposed. As well as the linear integrated circuits which containing bipolar transistors, an experimental basis for the anti-ionizing radiation effects of bipolar transistors is provided. (authors)

  4. Radiative effects of black carbon aerosols on Indian monsoon: a study using WRF-Chem model

    Science.gov (United States)

    Soni, Pramod; Tripathi, Sachchida Nand; Srivastava, Rajesh

    2018-04-01

    The Weather Research and Forecasting model with Chemistry (WRF-Chem) is utilized to examine the radiative effects of black carbon (BC) aerosols on the Indian monsoon, for the year 2010. Five ensemble simulations with different initial conditions (1st to 5th December, 2009) were performed and simulation results between 1st January, 2010 to 31st December, 2010 were used for analysis. Most of the BC which stays near the surface during the pre-monsoon season gets transported to higher altitudes with the northward migration of the Inter Tropical Convergence Zone (ITCZ) during the monsoon season. In both the seasons, strong negative SW anomalies are present at the surface along with positive anomalies in the atmosphere, which results in the surface cooling and lower tropospheric heating, respectively. During the pre-monsoon season, lower troposphere heating causes increased convection and enhanced meridional wind circulation, bringing moist air from Indian Ocean and Bay of Bengal to the North-East India, leading to increased rainfall there. However, during the monsoon season, along with cooling over the land regions, a warming over the Bay of Bengal is simulated. This differential heating results in an increased westerly moisture flux anomaly over central India, leading to increased rainfall over northern parts of India but decreased rainfall over southern parts. Decreased rainfall over southern India is also substantiated by the presence of increased evaporation over Bay of Bengal and decrease over land regions.

  5. Study on the anti-radiation effect of soyisoflavone and soyasaponins

    International Nuclear Information System (INIS)

    Sun Weiqi; Guo Ying; Zhang Yiquan; Yuan Xiaojie; Jing Xueyan; Chen Qiuli

    2007-01-01

    Objective: To investigate the anti-γ radiation effect of soyisoflavone and soyasaponins. Methods: Three batches in the experiment In every batch, clean rank of Kunming male mice were randomly divided into four groups: normal control group, radiated group, soyisoflavone group and soyasaponins group according to their weight. The mice in soy- isoflavone group and soyasaponins group were fed with soyisoflavone and soyasaponins for 30 days successively, then the mice were irradiated by 60 Co γ-rays in the whole body except those in the normal control group. After radiation, these two groups were fed equally as before. WBC contents, the Granulocytes and the Micronucleated polychromatic erythrocytes in bone-marrow, SOD activities and MDA contents in the blood and liver were measured. Results: On the third and the fourteenth day after radiation, the number of WBC in the blood and the number of the Granulocytes in bone-marrow, the activities of SOD in the blood and liver in soyisoflavone group and soyasaponins group were significantly higher than that of radiated group (P<0.05). The number of the Micronucleated polychromatic erythrocytes in bone - marrow and MDA contents in the blood were significantly lower than that of radiated group( P<0.05). Conclusion: Soyisofiavone and soyasaponins could prevent the WBC in distal blood and the Granuloeytes in bone-marrow decreasing in number after radiation, restrain the production of the Micronucleated polychromatic erythrocytes, improve the antioxidant ability of radiated mice, and release the irradiation injury from γ-rays. (authors)

  6. Radiation effects on vasoproliferation

    International Nuclear Information System (INIS)

    Yamaura, Hirotsugu; Matsuzawa, Taiju

    1975-01-01

    The authors quantitatively examined radiation effects on vascular proliferarion, using the rat transparent chamber technique to observe the living microcirculation. We studied the process of vasoproliferation and revascularization from the surrounding pre-existing vessels into the surgically avascularized area in the chamber, by measuring the vascular lenght photographically. A hyper-vascularized zone, about 0.5 mm in with, was formed on the vascularizing frontier, the significance of which is so far not known. When the chambers were irradiated with various doses of 60 Co γ-rays, a dose dependent inhibition of vasoproliferation was observed. (auth.)

  7. Radiation effects on vasoproliferation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaura, H; Matsuzawa, T [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis, Leprosy and Cancer

    1975-06-01

    The authors quantitatively examined radiation effects on vascular proliferarion, using the rat transparent chamber technique to observe the living microcirculation. We studied the process of vasoproliferation and revascularization from the surrounding pre-existing vessels into the surgically avascularized area in the chamber, by measuring the vascular lenght photographically. A hyper-vascularized zone, about 0.5 mm in with, was formed on the vascularizing frontier, the significance of which is so far not known. When the chambers were irradiated with various doses of /sup 60/Co ..gamma..-rays, a dose dependent inhibition of vasoproliferation was observed.

  8. Hereditary radiation effects in offspring of the second and third generations after irradiation of both grandparents. Experimental studies and Hereditary radiation effects in offspring of the first generation after irradiation of one and both parents. Experimental studies

    Energy Technology Data Exchange (ETDEWEB)

    Nefyodova, I.; Nefyodov, I [Medical Radiological Research Centre RAMS, Obninsk (Russian Federation)

    2000-05-01

    The parent study has investigated hereditary radiation effects in progeny of the second and third generations of Wistar rats after irradiation of both grandparents with doses of 2-4 Gy. Attention was focused on the relationship between stages of gametogenesis in grandparents at the moment of radiation exposure and death of progeny in embryogenesis and early postnatal ontogenesis. Totals of 4207 mature males and females Wistar rats, 13539 offspring of the second generation (F2) and 746 offspring of the third generation (F3) were the subjects of investigation. Male and female rat grandparents (P) of 220-250 g were exposed to an external single irradiation by gamma rays to doses of 2,3 and 4 Gy at a dose rate of 0.003 Gy.s{sup -1} ({sup 60}Co source). The animals were mated at different times after irradiation so that different stages in gametogenesis were studied. When F1 sexual maturity was achieved, F1 males of each experimental group were mated with intact females to produce F2 descendants from the father's line and conversely F1 females use mated with intact males to produce F2 descendants from the mother's line. Embryogenesis F2 was studied after euthanasia of some females by ether on the 20th day of pregnancy. The fetuses were scored for size and mass, pathology of viscera and skeleton and the total, pre- and postimplantation death of embryos was calculated. In addition development of young rats was observed for 30 days after the birth. The numbers surviving on the 1st and 30th days after the birth were calculated, giving the death rate for this period of time. It was stated: for F2; radiation effects depend upon a dose stage of gametogenesis of both P at the time of radiation exposure; F2 death in embryogenesis occurred only after irradiation of P with a dose of 4 Gy; ossification disorder of the skeleton in F2 embryogenesis was found in all experimental groups; high F2 death is observed after birth which depends much more on the stage of

  9. Hereditary radiation effects in offspring of the second and third generations after irradiation of both grandparents. Experimental studies and Hereditary radiation effects in offspring of the first generation after irradiation of one and both parents. Experimental studies

    International Nuclear Information System (INIS)

    Nefyodova, I.; Nefyodov, I

    2000-01-01

    The parent study has investigated hereditary radiation effects in progeny of the second and third generations of Wistar rats after irradiation of both grandparents with doses of 2-4 Gy. Attention was focused on the relationship between stages of gametogenesis in grandparents at the moment of radiation exposure and death of progeny in embryogenesis and early postnatal ontogenesis. Totals of 4207 mature males and females Wistar rats, 13539 offspring of the second generation (F2) and 746 offspring of the third generation (F3) were the subjects of investigation. Male and female rat grandparents (P) of 220-250 g were exposed to an external single irradiation by gamma rays to doses of 2,3 and 4 Gy at a dose rate of 0.003 Gy.s -1 ( 60 Co source). The animals were mated at different times after irradiation so that different stages in gametogenesis were studied. When F1 sexual maturity was achieved, F1 males of each experimental group were mated with intact females to produce F2 descendants from the father's line and conversely F1 females use mated with intact males to produce F2 descendants from the mother's line. Embryogenesis F2 was studied after euthanasia of some females by ether on the 20th day of pregnancy. The fetuses were scored for size and mass, pathology of viscera and skeleton and the total, pre- and postimplantation death of embryos was calculated. In addition development of young rats was observed for 30 days after the birth. The numbers surviving on the 1st and 30th days after the birth were calculated, giving the death rate for this period of time. It was stated: for F2; radiation effects depend upon a dose stage of gametogenesis of both P at the time of radiation exposure; F2 death in embryogenesis occurred only after irradiation of P with a dose of 4 Gy; ossification disorder of the skeleton in F2 embryogenesis was found in all experimental groups; high F2 death is observed after birth which depends much more on the stage of gametogenesis P than radiation

  10. Radiation effects on polyethylenes

    International Nuclear Information System (INIS)

    Suzuki, T.; Oki, Y.; Numajiri, M.; Miura, T.; Kondo, K.; Tanabe, Y.; Ishiyama, M.; Ito, Y.

    1992-01-01

    Radiation effects on four kinds of polyethylenes were studied from the viewpoints of mechanical properties, free radicals and free volumes. The samples were irradiated using a cobalt 60 gamma source to give doses up to 3MGy. The degradation of mechanical strength due to gamma-irradiation was evaluated by the elongation at break and its tensile strength. Radiation induced free radicals were measured by ESR. Free volumes observed by the o-Ps component of the positron annihilation spectrum are normally the large ones located in the amorphous regions and after irradiation these are created in crystalline regions, too. The sizes and the relative numbers of free volumes were evaluated by lifetimes and intensities of a long-lived component of positronium, respectively. Using these data, the properties of polyethylenes before and after irradiation are discussed. (author)

  11. Cumulative radiation effect

    International Nuclear Information System (INIS)

    Kirk, J.; Cain, O.; Gray, W.M.

    1977-01-01

    Cumulative Radiation Effect (CRE) represents a scale of accumulative sub-tolerance radiation damage, with a unique value of the CRE describing a specific level of radiation effect. Computer calculations have been used to simplify the evaluation of problems associated with the applications of the CRE-system in radiotherapy. In a general appraisal of the applications of computers to the CRE-system, the various problems encountered in clinical radiotherapy have been categorised into those involving the evaluation of a CRE at a point in tissue and those involving the calculation of CRE distributions. As a general guide, the computer techniques adopted at the Glasgow Institute of Radiotherapeutics for the solution of CRE problems are presented, and consist basically of a package of three interactive programs for point CRE calculations and a Fortran program which calculates CRE distributions for iso-effect treatment planning. Many examples are given to demonstrate the applications of these programs, and special emphasis has been laid on the problem of treating a point in tissue with different doses per fraction on alternate treatment days. The wide range of possible clinical applications of the CRE-system has been outlined and described under the categories of routine clinical applications, retrospective and prospective surveys of patient treatment, and experimental and theoretical research. Some of these applications such as the results of surveys and studies of time optimisation of treatment schedules could have far-reaching consequences and lead to significant improvements in treatment and cure rates with the minimum damage to normal tissue. (author)

  12. Physico-chemical studies of radiation effects in cells: Final report

    International Nuclear Information System (INIS)

    Powers, E.L.

    1987-03-01

    The career of Dr. E.L. Powers, a pioneer in the development of radiobiology, is reviewed. His initial research involved the effects of radiation and certain chemicals on Paramecium, associated ultrastructural studies on protozoan cells, responses of Rickettsia and bacteriophage to irradiation, and the development of techniques for studying bacterial spores. These efforts established the basic radiation biology of the spore and its importance in understanding the effects of free radicals, oxygen, and water. His recent research extended work on the dry spore to the very wet spore and to other selected chemical systems in aqueous suspension. 126 refs., 2 figs

  13. The use of ion beams to study radiation effects in metals

    International Nuclear Information System (INIS)

    Nelson, R.S.

    1978-01-01

    Particle accelerators are finding increasing use in the study of materials. This review concentrates on their application to study radiation damage effects. The first section deals with the basic interaction of particle beams with solids, the production of defects and their agglomeration, and phenomena such as irradiation-enhanced diffusion and precipitation. The second part of the review which complements a recent article (Mathews. Contemp. Phys.; 18:(6)571 (1977)), deals with the behaviour of materials in fast reactors. It discusses in some detail the application of particle accelerators to technological problems such as void formation in fast reactor materials and irradiation enhanced creep. (author)

  14. Life-span radiation effects studies in animals: what can they tell us

    International Nuclear Information System (INIS)

    Thompson, R.C.

    1984-05-01

    Results from life-span studies in a variety of animal species have found relatively little application in the development of radiation risk factors for various organs of man. This paper discusses possible reasons for this situation and presents recommendations to correct it

  15. Morpho-functional study of ionizing radiation effects on the rabbits' femoral vein

    International Nuclear Information System (INIS)

    Sakiyama, Mauro Yoshimitsu

    1995-01-01

    In this study we evaluate the effects of the ionizing radiation on the rabbits femoral vein. The samples of femoral vein were obtained from 56 New Zealand rabbits, male with ageing from 90 to 120 days, that were divided into 4 groups of 14 animals: one control group non-irradiated and three animal groups sacrificed 2 days, 14 days and 90 days after irradiation. In the three irradiated rabbits groups, each animal received the total dose 4000 cGy (rads) divided in 10 sessions of 400 cGy, a dose equivalent that utilized on clinical therapeutic. A morpho functional study of vein samples was carried out with: light microscopy: stained by hematoxin - eosin, Masson's tricromic, and Verhoeff. Immunohistochemical: reactions of immunoperoxidase with monoclonal mouse anti-human endothelial cell factor CD-31 and anti-human Von Willebrand factor (factor VIII), to study the vein endothelium. Histomorphometry of elastic fiber system stained by Weigert's resorcin-fuchsin with and without prior oxidation with oxone; for the study of mature, elaunin or pre-mature and oxytalan or young elastic fibers. Electronic microscopy: transmission and scanning. With the methodology utilized we observe changes in the femoral vein of the animals submitted to irradiation in relation to the control group, thus described: there is formation of vacuoles between the endothelium and the basal membrane, called sub endothelial vacuoles, in focal areas. The factor VIII and CD-31 endothelial antigens are preserved with no changes in their functions. Focal alterations are present in the endothelial surface with disorder in the setting and orientation of the endothelial cells. there is degeneration of the elastic fibers with significant decrease in their quantity in the stage, 2 days and 14 days after irradiation. There is increase in the quantity of elastic fibers in the late stage, 90 days after irradiation, tending to normality. In this present study, the changes described are not accompanied by venous

  16. Radiation effects in optoelectronic devices

    International Nuclear Information System (INIS)

    Barnes, C.E.

    1977-03-01

    A summary is given of studies on radiation effects in light-emitting diodes, laser diodes, detectors, optical isolators and optical fibers. It is shown that the study of radiation damage in these devices can provide valuable information concerning the nature of the devices themselves, as well as methods of hardening these devices for applications in radiation environments

  17. Study of the cell cycle control for human malignant mesothelioma lines. Interferon and radiations effect

    International Nuclear Information System (INIS)

    Vivo, C.

    1999-01-01

    In order to better understand the inhibition mechanisms of the IFN-R-HU on tumoral development, the IFN-R-U effect on MM lines has been studied. Three groups of lines has been distinguished: eight sensitive lines, two intermediate and three resistant. The sensitive lines showed a triple locking of the cell cycle: in phases S, G1 and G2. The study of the cell cycle control points function, realized by the MM lines radiation exposure showed the points function on G1/S and-or on G2/M and the dependence or non dependence of the cycle stop of the protein P53 and P21 W at F1/CIP1. (A.L.B.)

  18. Study of the initial processes of radiation effects using synchrotron radiation

    International Nuclear Information System (INIS)

    Kobayashi, Katsumi

    1990-01-01

    Necessity for the research of production mechanisms of molecular damages in biological system and usefulness of monochromatic soft X-ray in these studies are described. Synchrotron radiation are introduced as a strong light source with continuous spectrum. Practically, it is the only light source in soft X-ray and vacuum UV region. Development of irradiation apparatus for radiation biology and recent results using various biological systems are reviewed. (author)

  19. Radiation effects-prevalence of contributory risk factors a pilot study in Visakhapthnam steel plant

    International Nuclear Information System (INIS)

    Lakshman rao, K. V.

    2004-01-01

    Integrated Steel Plants contribute significant air pollution, water pollution and solid waste generation. Diverse occupational health hazards present is steel industry pose ill effects to the industrial workers. Occupational health services and research center (OHS and RC) of this plant established in the year 1992 to protect the health and well-being of all the employees working in different occupations. the primary role OHS and RC is to conduct periodical medical examinations, monitoring of the working environments, suggest the suitable personal protective equipment to the workers, evaluate risk factors, work practices, risk management and industrial toxicological studies. Dissemination of information related to occupational health and safety to the working population through regular educational sessions at the workplaces as at training and development center (T and DC) is also part of our services. The proneness for effects of exposure to ionizing radiation is enhanced by various factors related to the family history of chronic diseases, nutritional status of the individuals, the lifestyle factors apart from psycho-social factors like illiteracy, ignorance, negligence and inadequate utilization of personal protective equipment (PPE) at workplace. To evaluate the prevalence of such contributory risk factors, a pilot study has been conducted in Visakhapatnam Steel Plant. The data is obtained through routine periodical medical examination of workers at the Occupational Health Services Center through standard format. The study revealed statistically high prevalence of the risk factors and indicated the necessity of intensifying primary prevention methods in addition to environmental control and usage of PPE. (Author)

  20. Study by dislocation dynamics simulations of radiation effects on the plasticity of ferrite at high temperature

    International Nuclear Information System (INIS)

    Shi, Xiangjun

    2014-01-01

    This study is a contribution to the multi-scale modeling of hardening and embrittlement of the vessel steel in Pressurized Water Reactors (PWR) under irradiation conditions. Dislocation Dynamics simulations (DD) were conducted to describe the plasticity of irradiated iron at grain scale. Quantitative information about the pinning strength of radiation-induced loops was extracted and can be transferred at crystal plasticity scale. Elementary interactions between an edge dislocation and different types of loops were first analyzed. A new model of DD was identified and validated, both qualitatively in terms of interaction mechanisms and quantitatively in terms of critical stress, using Molecular Dynamics results available in the literature. The influence of the size of the loops and of the strain rate was particularly studied. Elementary simulations involving a screw dislocation and the same radiation-induced defects were conducted and carefully compared to available MD results, extending the range of validity of our model. Finally, a set of massive simulations involving an edge dislocation and a large number of loops was performed and allowed a first estimation of the obstacle strength for this type of defects (α≅0.26). This value is in a good agreement with previous experimental and numerical studies, and gives us confidence in future work based on this new DD model. (author) [fr

  1. Radiation effects-prevalence of contributory risk factors a pilot study in Visakhapthnam steel plant

    Energy Technology Data Exchange (ETDEWEB)

    Lakshman rao, K. V.

    2004-07-01

    Integrated Steel Plants contribute significant air pollution, water pollution and solid waste generation. Diverse occupational health hazards present is steel industry pose ill effects to the industrial workers. Occupational health services and research center (OHS and RC) of this plant established in the year 1992 to protect the health and well-being of all the employees working in different occupations. the primary role OHS and RC is to conduct periodical medical examinations, monitoring of the working environments, suggest the suitable personal protective equipment to the workers, evaluate risk factors, work practices, risk management and industrial toxicological studies. Dissemination of information related to occupational health and safety to the working population through regular educational sessions at the workplaces as at training and development center (T and DC) is also part of our services. The proneness for effects of exposure to ionizing radiation is enhanced by various factors related to the family history of chronic diseases, nutritional status of the individuals, the lifestyle factors apart from psycho-social factors like illiteracy, ignorance, negligence and inadequate utilization of personal protective equipment (PPE) at workplace. To evaluate the prevalence of such contributory risk factors, a pilot study has been conducted in Visakhapatnam Steel Plant. The data is obtained through routine periodical medical examination of workers at the Occupational Health Services Center through standard format. The study revealed statistically high prevalence of the risk factors and indicated the necessity of intensifying primary prevention methods in addition to environmental control and usage of PPE. (Author)

  2. Numerical Study of Thermal Radiation Effect on Confined Turbulent Free Triangular Jets

    Directory of Open Access Journals (Sweden)

    Kiyan Parham

    2013-01-01

    Full Text Available The present study investigates the effects of thermal radiation on turbulent free triangular jets. Finite volume method is applied for solving mass, momentum, and energy equations simultaneously. Discrete ordinate method is used to determine radiation transfer equation (RTE. Results are presented in terms of velocity, kinetic energy, and its dissipation rate fields. Results show that thermal radiation speeds the development of velocity on the jet axis and enhances kinetic energy; therefore, when radiation is added to free jet its mixing power, due to extra kinetic energy, increases.

  3. Determining the infrared radiative effects of Saharan dust: a radiative transfer modelling study based on vertically resolved measurements at Lampedusa

    Science.gov (United States)

    Meloni, Daniela; di Sarra, Alcide; Brogniez, Gérard; Denjean, Cyrielle; De Silvestri, Lorenzo; Di Iorio, Tatiana; Formenti, Paola; Gómez-Amo, José L.; Gröbner, Julian; Kouremeti, Natalia; Liuzzi, Giuliano; Mallet, Marc; Pace, Giandomenico; Sferlazzo, Damiano M.

    2018-03-01

    Detailed measurements of radiation, atmospheric and aerosol properties were carried out in summer 2013 during the Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region (ADRIMED) campaign in the framework of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) experiment. This study focusses on the characterization of infrared (IR) optical properties and direct radiative effects of mineral dust, based on three vertical profiles of atmospheric and aerosol properties and IR broadband and narrowband radiation from airborne measurements, made in conjunction with radiosonde and ground-based observations at Lampedusa, in the central Mediterranean. Satellite IR spectra from the Infrared Atmospheric Sounder Interferometer (IASI) are also included in the analysis. The atmospheric and aerosol properties are used as input to a radiative transfer model, and various IR radiation parameters (upward and downward irradiance, nadir and zenith brightness temperature at different altitudes) are calculated and compared with observations. The model calculations are made for different sets of dust particle size distribution (PSD) and refractive index (RI), derived from observations and from the literature. The main results of the analysis are that the IR dust radiative forcing is non-negligible and strongly depends on PSD and RI. When calculations are made using the in situ measured size distribution, it is possible to identify the refractive index that produces the best match with observed IR irradiances and brightness temperatures (BTs). The most appropriate refractive indices correspond to those determined from independent measurements of mineral dust aerosols from the source regions (Tunisia, Algeria, Morocco) of dust transported over Lampedusa, suggesting that differences in the source properties should be taken into account. With the in situ size distribution and the most appropriate refractive index the estimated dust IR radiative forcing

  4. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  5. Experimental Studies of Some Physical Properties of Some Chalcogenide Materials and Its Response to Radiation Effect

    International Nuclear Information System (INIS)

    Elnagar, D.M.A.

    2011-01-01

    Se 100-x Bi x system with (x = 0, 5, and 10) amorphous alloys were prepared by the standard melt quenching technique. Homogenous thin films for optical and electrical measurements were prepared using thermal evaporation method with heating substrates at constant temperature ∼ 150 degree C. D.C. conductivity at different temperatures was measured for thin films of the system. The obtained results were found to be reproducible for the different films of the same composition which indicate their stability and homogeneity. More than one region of temperature-dependence of conductivity was clearly observed. The conduction of activation energy was determined for all compositions. The sample with x = 5 exhibits the smallest activation energy and this may be attributed to shift of the Fermi level through the gap. Another possibility can be related to the local order which plays a major role in determining the semiconducting properties of materials. The density of the localized states at the Fermi level N(Ef) was calculated. It increases with the incorporation of Bi in the Se glassy network from 1021 to 1023 eV -1 cm -3 respectively. It was found that the values of the hopping energy (W) and the degree of disorder (To) decrease with increasing Bi concentration. Optical absorption of the films under study was measured in the wavelength range from 200 to 1100 nm at room temperature. Optical absorption edge was found to shift towards the lower energy side of the spectrum. The optical absorption data follow a law of the form: αhv=b(hv-E T ) 2 where (α) is the absorption coefficient, (hν) is the photon energy, (B) is the slope of Tauc edge called band tailing parameter, and (E T ) is the optical band gap energy. This indicates that the dominant type of electronic transitions for the system of compositions under study is the indirect electronic transition. The (E T ) value obtained by extrapolating the square-law dependence of the absorption Abstract coefficient (α) data to

  6. Study of radiation effects on the senescence accelerated mouse (SAM), 1

    International Nuclear Information System (INIS)

    Kishikawa, Masao; Iseki, Masachika; Kondo, Hisayoshi

    1989-01-01

    The study of age-related changes in the central nervous system due to irradiation is being carried out in our laboratory. The senescence accelerated mouse (SAM P/1, male) was used for this investigation concerning the one-trial passive avoidance reaction. The experimental group of SAM P/1 was irradiated with 4 Gy at 8 weeks old, and passive avoidance reaction (PAR) was measured for 180 seconds as a learning task. At the age of 7 months, statistical analysis of PAR was conducted using the life time analysis method. The passive avoidance reaction of the irradiated group was more impaired than that of the control group. The results of this investigation suggested that the learning and/or memory disturbance of irradiated SAM P/1 is similar to the changes of more aged SAM P/1. (author)

  7. Electron microscope studies of methotrexate and radiation effects in human squamous cell carcinoma of the mouth

    International Nuclear Information System (INIS)

    De Martino, C.

    1974-01-01

    Serial biopsy specimens from two squamous cell carcinomas of the mouth were studied by electron microscopy. This report described the ultrastructural changes in the cells produced by treatment with methotrexate followed by irradiation. The main ultrastructural findings after treatment are: numerous autophagic lysosomes and residual bodies are visible in the cytoplasm of the tumor cells; mitochondria are swollen. The mitochondrial cristae are distorted and disrupted, and mitochondrial matrix disappears; the nucleolus shows a series of morphological changes such as development of a compact nucleolus, aggregation of granular elements, atrophy, dissolution and fragmentation of the nucleolar mass; infiltration of lymphocytes, granulocytes and macrophages in the tumor. The significance of these ultrastructural findings is discussed. (U.S.)

  8. Studies of the ionizing radiation effects on the effluents acute toxicity due to anionic surfactants

    International Nuclear Information System (INIS)

    Moraes, Maria Cristina Franco de

    2004-01-01

    Several studies have shown the negative effects of surfactants, as detergents active substance, when discharged on biological sewage wastewater treatment plants. High toxicity may represent a lower efficiency for biological treatment. When surfactants are in aquatic environment they may induce a loss of grease revetment on birds (feather). Depending on the surfactant concentration, several damages to all biotic systems can happen. Looking for an alternative technology for wastewater treatment, efficient for surfactant removal, the present work applied ionizing radiation as an advanced oxidation process for affluents and effluents from Suzano Treatment Station. Such wastewater samples were submitted to radiation using an electron beam from a Dynamic Electron Beam Accelerator from Instituto de Pesquisas Energeticas e Nucleares. In order to assess this proposed treatment efficacy, it was performed acute toxicity evaluation with two test-organisms, the crustacean Daphnia similis and the luminescent bacteria Vibrio fischeri. The studied effluents were: one from a chemical industry (IND), three from sewage plant (affluents - GG, GM and Guaio) and the last biologically treated secondary effluent (EfF), discharged at Tiete river. The applied radiation doses varied from 3 kGy to 50 kGy, being 50 kGy enough for surfactant degradation contained at industrial effluent. For GG, GM and Guaio samples, doses of 6 kGy and 10 kGy were efficient for surfactant and toxicity reduction, representing an average removal that varied from 71.80% to 82.76% and toxicity from 30% to 91% for most the effluents. The final effluent was less toxic than the others and the radiation induced an average 11% removal for anionic surfactant. The industrial effluents were also submitted to an aeration process in order to quantify the contribution of surfactant to the whole sample toxicity, once it was partially removed as foam and several fractions were evaluated for toxicity. (author)

  9. Application of a Pelletron accelerator to study total dose radiation effects on 50 GHz SiGe HBTs

    Energy Technology Data Exchange (ETDEWEB)

    Praveen, K.C.; Pushpa, N.; Naik, P.S. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India); Cressler, John D. [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Tripathi, Ambuj [Inter University Accelerator Centre (IUAC), New Delhi 110 067 (India); Gnana Prakash, A.P., E-mail: gnanaprakash@physics.uni-mysore.ac.in [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Total dose effects of 50 MeV Li3+ ion on 50 GHz SiGe HBTs is investigated. Black-Right-Pointing-Pointer Ion irradiated results were compared with Co-60 gamma results. Black-Right-Pointing-Pointer 50 MeV Li ions create more damage in E-B spacer oxide when compared to Co-60 gamma radiation. Black-Right-Pointing-Pointer Co-60 gamma radiation create more damage in STI oxide when compared to 50 MeV Li ions. Black-Right-Pointing-Pointer Worst case total dose radiation effects can be studied using Pelletron accelerator facilities. - Abstract: We have investigated the effects of 50 MeV lithium ion irradiation on the DC electrical characteristics of first-generation silicon-germanium heterojunction bipolar transistors (50 GHz SiGe HBTs) in the dose range of 600 krad to 100 Mrad. The results of 50 MeV Li{sup 3+} ion irradiation on the SiGe HBTs are compared with 63 MeV proton and Co-60 gamma irradiation results in the same dose range in order to understand the damage induced by different LET species. The radiation response of emitter-base (EB) spacer oxide and shallow trench isolation (STI) oxide to different irradiation types are discussed in this paper. We have also focused on the efficacy in the application of a Pelletron accelerator to study total dose irradiation studies in SiGe HBTs.

  10. Utilization of rice husk ash as filler for polyamide 6 and ionizing radiation effect studies on this composite

    International Nuclear Information System (INIS)

    Ferro, Waldir Pedro

    2009-01-01

    In order to improve the dimensional stability, as well as, electrical, mechanical and thermal properties of polymers, new filler to this purpose has been developed. The mos applied filler to propitiate the features previously mentioned are the glass and carbon fibers, the mineral filler as the calcium carbonate, the talc and the micro glass sphere. The main aim of this work was to study the rice husk ash as filler for polyamide 6 and ionizing radiation effect studies on this composite, irradiated by electron beam at different doses, since it is constituted of at least 90% of silicon dioxide, and compared with the talc which is the most applied mineral filler. This comparison was made from a compound made through the refined rice husk ash and the polyamide 6 (PA 6), which is one of the main engineering plastic with applications in several productive areas. The samples were injected and irradiated in a electron accelerator. Afterwards, their mechanical and thermal properties were measured. It was also inject automotive parts to verify the processing of the PA 6 with CCA. The results showed that the use of the rice husk ash as filler for polyamide 6 composite is technically and economically viable. The irradiation of the studied composite (PA 6 with 30% of rice husk ash) did not provide any improvement for the mechanical and thermal properties previously appraised. (author)

  11. A functional and chemical study of radiation effects on rat parotid and submandibular/sublingual glands

    International Nuclear Information System (INIS)

    Vissink, A.; S-Gravenmade, E.J.; Ligeon, E.E.; Konings, W.T.

    1990-01-01

    The aim of this study was to monitor composition and rate of secretion of rat parotid and submandibular/sublingual saliva following local single doses of X-rays ranging from 5 to 20 Gy. Pilocarpine-stimulated samples of parotid and submandibular/sublingual saliva were simultaneously collected with miniaturized Lashley cups before and 1-30 days after irradiation. The lag phase (period between injection of pilocarpine and start of the secretion) and flow rate were recorded and the concentrations of sodium, potassium, calcium, phosphate, and amylase were measured. With increasing dose and time, the salivary flow rate as well as sodium concentration decreased, while potassium concentrations increased throughout the follow-up period. The lag phase and the concentration of amylase reached their maximum at 3 and 10 days after irradiation, respectively. The changes in lag phase and flow rate were most obvious after doses of 15 or 20 Gy and showed a great similarity for parotid and submandibular/sublingual saliva. No dose-response relationship was observed for the changes in concentrations of calcium and phosphate. It is concluded that for radiation doses of 10 Gy and above, irreversible changes (lag phase, flow rate, potassium, sodium) were observed. A saturation of the irradiation effects (lag phase, flow rate) seems to exist at doses larger than 15 Gy. No significant differences were observed between the radiation-induced functional changes in parotid and submandibular/sublingual salivary gland tissue

  12. Studies on the synthesis and anti-radiation effect of 16-β-epiestriol

    International Nuclear Information System (INIS)

    Tong Zengshou; Zheng Sixin; Wang Peiren; Li Lu; Huang Mingxin

    1990-01-01

    The synthesis and radioprotective effect of 16 - β - epiestriol(2) are reported. The key intermediate, 16-ketoestradiol(7) was prepared by the reaction of 16α, 17α-epoxide estradiol diacetate(4) and methanolic potassium hydroxide. Epiestriol(2) was obtained by reduction of compound(7). Pharmacological study showed that the radioprotective effect of epiestriol at 9.0 Gy was higher than that of estriol(1) with 0.1 mg per mouse injected peritoneally 24 hr before irradiation, the survival rate with epiestriol was 85% higher than the control group, while estriol only elevated it by 50% under the same conditions. The slope of the survival-radiation dose curve with epiestriol was less steep than that with estriol. The structure-activity relationship and radioprotective effect of epiestriol and estriol suggest that the 16β-effect of steric factors on the receptor is one of the main effects. The 16β-hydroxyestriol appears to have the optimal radioprotective potency, in comparison with the 16β-hydroxyestriol

  13. Study of the ionizing radiation effect on the polyamide 6,6 mechanical properties

    International Nuclear Information System (INIS)

    Colombo, Maria Aparecida da Silva

    2004-01-01

    Polyamide 6,6 due to its excellent mechanical, thermal and electrical properties and its great performance in multiple industrial applications is considered one of the most important engineering polymers. However, in specific applications, some of its properties need to be improved by means additives or fillers to reach the required properties increasing its final cost. By these considerations, the aim of this work was to apply the ionizing radiation to improve the natural mechanical properties of polyamide 6,6. Also, to evaluate the irradiation parameters, and the mechanical performance of the irradiated polymer in order to use the cross-linking, induced by ionizing radiation, as substitute of additives and fillers. Row polyamide 6,6 samples, for mechanical tests, were prepared by injection molded and then irradiated with high energetic electrons to reach doses of 70, 100, 150, and 200 kGy. The mechanical performance, of non-irradiated and irradiated samples, was evaluated by tensile strength, impact, hardness and wear measurements. Furthermore, hardness and wear tests were carried out with samples, which were immersed in petroleum and sea water for 6 months. The experimental results have shown that, in the studied dose range, the tensile strength increases 25%, the hardness Shore D 15%, the impact values diminished by 80% and the wear values decreased 20 times between 0 and 200 kGy. The effect of the petroleum and sea water were shown mainly in the nonirradiated samples. (author)

  14. Space radiation effects

    International Nuclear Information System (INIS)

    Li Shiqing; Yan Heping

    1995-01-01

    The authors briefly discusses the radiation environment in near-earth space and it's influences on material, and electronic devices using in space airship, also, the research developments in space radiation effects are introduced

  15. Study of radiation effects on some glasses and their applications in radiation dosimetry

    International Nuclear Information System (INIS)

    Mohammad, A.El.

    2008-01-01

    This thesis comprises a study of the X-ray diffraction, thermal, electrical, ESR and optical properties of lead lithium tetra borate glass. The objective of this thesis is to prepare glass dosimeter and study the effect of several gamma-irradiation doses on Lead lithium tetra borate glasses doped with Cu O. The two glasses were prepared from chemical reagents; Li 2 B 4 O 7 from ready package, lead and copper oxide were added in fixed Proportions. The glass melting was made in porcelain crucibles, using electrically heated furnace at temperature of 1000 -1100 degree C. The melts rapidly quenched in air by pressing between two stainless-steel plates mould kept at room temperature. The resultant glasses were colorless for LPTB and transparent greenish sheet of LPTB Cu glass about 0.8 mm thick and where polished to meet the requirements for optical and electrical measurements. The obtained results can be summarized as follows:- Density It is observed that, for unirradiated samples, the addition of copper to LPTB leads to the increase of the number of ions in the sample which decreases the inter-ionic distance. As a result, the molar volume of LPTB Cu decreased and consequently its density increased in the range of 10 ± 1 %. Irradiation with gamma rays is assumed to create displacements, electronic defects and /or breaks in the network bonds. Irradiation can cause the compaction of B 2 O 3 by breaking of the bonds between trigonal elements, allowing the formation of different configuration. Irradiating the LPTB glass with growing gamma doses up to 25 kGy decreased its molar volume with in 4.07 % and consequently increased the density with the same percentage. For the glass LPTB Cu, the effect of gamma rays appeared as a decrease in the molar volume and increase in density with the same percentage (12.9%). The addition traces of copper (0.01 weight %) to LPTB enhanced the effect of gamma radiation on it. Crystallization Behavior: - X-ray diffraction The results show

  16. A sem study of radiation effects on the rat molar enamel formation

    International Nuclear Information System (INIS)

    Lee, Kyung Ho; Park, Tae Won

    1995-01-01

    The purpose of this study was to investigate the effects of radiation on the formation of rat molar enamel at the developmental stages. The experimental animals were divided into five groups and were irradiated single dose of 396 cGy; 1st group on 14th day of gestation, 2nd group on 19th day of gestation, 3rd group on 3 days after birth, 4th group on 8 days after birth, 5th group on 28 days after birth. The control and 1, 2, 3 and 4th experimental groups were sacrificed on 2, 4, and 6 weeks and the 5th groups were sacrificed on 1 day and 2 weeks after irradiation. Distal 1/2 and occlusal 1/3 enamel surface of lingual side of lingual cusp, and fractured surface of lingual side of lingual cusp in a longitudinal direction of the mandibular first molar were examined using scanning electron microscope. The following results were obtained: 1. The roughness of enamel surface and enamel hypoplsia were increased in a sequence of 4th, 1st, 2nd, and 3rd experimental group, and the enamel cracks were increased in the 1st and 2nd experimental group. 2. The pattern of enamel hypoplasia had a network from on the 1st and 2nd experimental group, and appeared a linear shape on the 3rd experimental group, and then the crator-like enamel defects were observed in all experimental groups(especially 1st and 2nd experimental group) except 5th. 3. Dentinoenamel junction showed the clear-cut and straight appearance except 5th experimental group. 4. There was no significant difference between 5th experimental and control group.

  17. The study of the radiation protection of propolis to the radiation effects in mice

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Y.H.; Suzuki, Ikukatsu; Hasegawa, Takeo; Muto, H. [Suzuka Univ. of Medical Science, Mie (Japan); Yanagisawa, Takaharu; Iwasa, Toshihiro; Bamen, K.

    2000-05-01

    The profit which radiation brought to the Homo sapiens is very big. But, radiation has even harmful parameter for the human besides one case. After effect on man to the radiation is thought about, the individual of which sensibility is the highest is a fetus. Therefore, even an effects to this fetus is grasped precisely, and protection criterion and resource are decided from the viewpoint of the protection of radiation as well. If it does so, a child and maturitas aren't so difficult as in the protection of radiation and the managerial side. It was examined about control group, propolis administration chisels for medical use group, 1.5 Gy independent exposure group and propolis pluse 1.5 Gy group in this study. It was examined about the protection of radiation of propolis which to malformation, fetal death, arrested development, and so on in the organogenesis (8 days post conception) being done when sensibility is the highest against the teratogenesis. Preimplantation death rate was compared with the control group and the sham control group, and statistical significant difference wasn't recognized by a 1.5 Gy radiation independent exposure group, propolis administration 1.5 Gy radiation exposure group. As for the embryonic death rate, propolis was administered, and obviously embryonic death rate was poorer than the 1.5 Gy independent exposure group, and significant difference was recognized by a 1.5 Gy radiation exposure group (p<0.001). It has a 1.5 Gy radiation exposure group made clear by this research fetal death rate propolis administer more only 1.5 Gy exposure fetal death rate development low (p<0.001). Fetal death rate wasn't recognized by propolis administration group (Sham control). As for the teratogenesis rate, propolis was administered, and the teratogenesis rate of the 1.5 Gy radiation exposure group was higher than the 1.5 Gy radiation independent exposure group. But, this is thought anamorphosis appear by propolis administration so

  18. The study of the radiation protection of propolis to the radiation effects in mice

    International Nuclear Information System (INIS)

    Gu, Y.H.; Suzuki, Ikukatsu; Hasegawa, Takeo; Muto, H.; Yanagisawa, Takaharu; Iwasa, Toshihiro; Bamen, K.

    2000-01-01

    The profit which radiation brought to the Homo sapiens is very big. But, radiation has even harmful parameter for the human besides one case. After effect on man to the radiation is thought about, the individual of which sensibility is the highest is a fetus. Therefore, even an effects to this fetus is grasped precisely, and protection criterion and resource are decided from the viewpoint of the protection of radiation as well. If it does so, a child and maturitas aren't so difficult as in the protection of radiation and the managerial side. It was examined about control group, propolis administration chisels for medical use group, 1.5 Gy independent exposure group and propolis pluse 1.5 Gy group in this study. It was examined about the protection of radiation of propolis which to malformation, fetal death, arrested development, and so on in the organogenesis (8 days post conception) being done when sensibility is the highest against the teratogenesis. Preimplantation death rate was compared with the control group and the sham control group, and statistical significant difference wasn't recognized by a 1.5 Gy radiation independent exposure group, propolis administration 1.5 Gy radiation exposure group. As for the embryonic death rate, propolis was administered, and obviously embryonic death rate was poorer than the 1.5 Gy independent exposure group, and significant difference was recognized by a 1.5 Gy radiation exposure group (p<0.001). It has a 1.5 Gy radiation exposure group made clear by this research fetal death rate propolis administer more only 1.5 Gy exposure fetal death rate development low (p<0.001). Fetal death rate wasn't recognized by propolis administration group (Sham control). As for the teratogenesis rate, propolis was administered, and the teratogenesis rate of the 1.5 Gy radiation exposure group was higher than the 1.5 Gy radiation independent exposure group. But, this is thought anamorphosis appear by propolis administration so long as there was

  19. Study of the rice husk ash utilization as filler polypropylene matrix and ionization radiation effect on this composite

    International Nuclear Information System (INIS)

    Alfaro, Eduardo de Faria

    2010-01-01

    In the first step of this work, it was evaluated the possibility of using rice husk ash as a filler in polypropylene (PP) making a comparison with talc which is the most used mineral filler in polymers. This comparison was made by using polypropylene with 20% rice husk ash as well as polypropylene with 20% talc measuring their properties. Despite the properties of the PP with 20% rice husk ash decreased compared with the composite of polypropylene with 20% talc it can be said that the rice husk ash can be used as filler for or other utilization less noble of PP . This way it is being given a destination for this residue that it is disposable in the environment contributing to its preservation, moreover reducing the product cost. This work had also as an aim to study the ionizing radiation effect in the properties of these composites. It was used the coupling agent, maleic anhydride , to verify a best sample homogenization. According to the results it can be said that PP is a semicrystalline polymer, and so it has its morphology modified when exposed to the irradiation process. This fact is due to the scission mechanisms of the polymeric chains which it is in compliance to the literature. (author)

  20. Cancer risk among children of atomic bomb survivors. A review of RERF epidemiologic studies. Radiation Effects Research Foundation

    International Nuclear Information System (INIS)

    Yoshimoto, Y.

    1990-01-01

    This article summarizes recent epidemiologic studies of cancer risk among the children of atomic bomb survivors conducted at the Radiation Effects Research Foundation. These children include two groups: (1) the in utero-exposed children (ie, those born to mothers who had been pregnant at the time of the bombings of Hiroshima and Nagasaki) and (2) the F1 population, which was conceived after the atomic-bombings and born to parents of whom one or both were atomic bomb survivors. Although from 1950 to 1984 only 18 cancer cases were identified among the in utero sample, cancer risk did appear to significantly increase as maternal uterine dose increased. However, since the observed cases are too few in number to allow a site-specific review, the increased cancer risk cannot be definitively attributed to atomic bomb radiation, as yet. For those members of the F1 population who were less than 20 years old between 1946 and 1982, cancer risk did not appear to increase significantly as parental gonadal dose increased. Follow-up of this population will continue to determine if the patterns of adult-onset cancer are altered

  1. Report of the APS summer study on physics problems relating to energy technologies: radiation effects on materials

    International Nuclear Information System (INIS)

    Vook, F.L.; Birnbaum, H.K.; Blewitt, T.H.

    1974-06-01

    The status of research and development programs related to radiation effects on materials is reviewed. Information is included on point defects in metals, dislocations, radiation damage, simulation of neutron damage, H and He in metals, insulators, semiconductors, and superconductors. (U.S.)

  2. Radiation effects in ice: New results

    International Nuclear Information System (INIS)

    Baragiola, R.A.; Fama, M.; Loeffler, M.J.; Raut, U.; Shi, J.

    2008-01-01

    Studies of radiation effects in ice are motivated by intrinsic interest and by applications in astronomy. Here we report on new and recent results on radiation effects induced by energetic ions in ice: amorphization of crystalline ice, compaction of microporous amorphous ice, electrostatic charging and dielectric breakdown and correlated structural/chemical changes in the irradiation of water-ammonia ices

  3. Radiation effects of ion beams on polymers

    International Nuclear Information System (INIS)

    Tagawa, Seiichi

    1993-01-01

    Recent progress in the radiation effects of ion beams on polymers are reviewed briefly. Our recent work on the radiation effects of ion beams on polystyrene thin films on silicon wafers and time resolved emission studies on polymers are described. (orig.)

  4. A long-term study of aerosol–cloud interactions and their radiative effect at the Southern Great Plains using ground-based measurements

    Directory of Open Access Journals (Sweden)

    E. T. Sena

    2016-09-01

    Full Text Available Empirical estimates of the microphysical response of cloud droplet size distribution to aerosol perturbations are commonly used to constrain aerosol–cloud interactions in climate models. Instead of empirical microphysical estimates, here macroscopic variables are analyzed to address the influence of aerosol particles and meteorological descriptors on instantaneous cloud albedo and the radiative effect of shallow liquid water clouds. Long-term ground-based measurements from the Atmospheric Radiation Measurement (ARM program over the Southern Great Plains are used. A broad statistical analysis was performed on 14 years of coincident measurements of low clouds, aerosol, and meteorological properties. Two cases representing conflicting results regarding the relationship between the aerosol and the cloud radiative effect were selected and studied in greater detail. Microphysical estimates are shown to be very uncertain and to depend strongly on the methodology, retrieval technique and averaging scale. For this continental site, the results indicate that the influence of the aerosol on the shallow cloud radiative effect and albedo is weak and that macroscopic cloud properties and dynamics play a much larger role in determining the instantaneous cloud radiative effect compared to microphysical effects. On a daily basis, aerosol shows no correlation with cloud radiative properties (correlation = −0.01 ± 0.03, whereas the liquid water path shows a clear signal (correlation = 0.56 ± 0.02.

  5. Radiation effects on lymphocytes

    International Nuclear Information System (INIS)

    Roser, B.

    1976-01-01

    This review of the ontogeny of lymphocyte populations concentrates on sites of production, rates of production, and the factors governing the differentiation and longevity of the various lymphocyte pools. The physiology of the lymphocyte pools is described with particular emphasis on recirculation from blood to lymph through lymphoid tissues. The separate routes of recirculation of both thymus-derived and nonthymus-derived lymphocytes and the possible anatomical sites and mechanisms of lymphocyte cooperation are discussed. Radiation effects on lymphocyte populations are divided into two sections. First, the effects of whole-body irradiation on the total lymphocyte pools are discussed including the differential effects of irradiation on T lymphocytes, B lymphocytes, lymphoblasts, and plasma cells. The differential sensitivity of various types of immune response is correlated, where possible, with the differential sensitivity of the lymphocyte types involved. Second, experimental attempts to selectively deplete discrete subpopulations of the total lymphocyte pools, e.g., recirculating cells, are briefly discussed with particular emphasis on studies on the effects of the localization of radionuclides in lymphoid tissue

  6. Radiation effects in space

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1987-07-01

    As more people spend more time in space, and the return to the moon and exploratory missions are considered, the risks require continuing examination. The effects of microgravity and radiation are two potential risks in space. These risks increase with increasing mission duration. This document considers the risk of radiation effects in space workers and explorers. 17 refs., 1 fig., 4 tabs

  7. Radiation effects in optoelectronic devices

    International Nuclear Information System (INIS)

    Barnes, C.E.; Wiczer, J.J.

    1984-05-01

    Purpose of this report is to provide not only a summary of radiation damage studies at Sandia National Laboratories, but also of those in the literature on the components of optoelectronic systems: light emitting diodes (LEDs), laser diodes, photodetectors, optical fibers, and optical isolators. This review of radiation damage in optoelectronic components is structured according to device type. In each section, a brief discussion of those device properties relevant to radiation effects is given

  8. Radiation Effects Research Foundation

    International Nuclear Information System (INIS)

    1979-01-01

    The last day of March 1978 marked the completion of the first 3 years of operation of the Radiation Effects Research Foundation in Hiroshima and Nagasaki. RERF was established on 1 April 1975 as successor to the Atomic Bomb Casualty Commission which had been in continuous operation since 1947. This record of the first 3 years of operation consists of selected reports and other documents prepared in the course of conducting the business of RERF and includes a brief history, a late radiation effects that might be conducted at RERF. The wisdom and thought given to the research program and its operation by the Scientific Council and the Board of Directors is reflected in the minutes of their meetings which are included in the Appendix. (Mori, K.)

  9. Biological radiation effects

    International Nuclear Information System (INIS)

    Kiefer, J.

    1989-01-01

    The book covers all aspects of biological radiation effects. The physical basis is dealt with in some detail, and the effects at the subcellular and the cellular level are discussed, taking into account modern developments and techniques. The effects on the human organism are reviewed, both from the point of view of applications in medicine as well as with regard to radiation hazards (teratogenic, gonadal and carcinogenic effects)

  10. Radiation effects and radiation risks

    International Nuclear Information System (INIS)

    Lengfelder, E.; Forst, D.; Feist, H.; Pratzel, H.

    1988-01-01

    The book presents the facts and the principles of assessment and evaluation of biological radiation effects in general and also with particular reference to the reactor accident of Chernobyl, reviewing the consequences and the environmental situation on the basis of current national and international literature, including research work by the authors. The material compiled in this book is intended especially for physicians, but will also prove useful for persons working in the public health services, in administration, or other services taking care of people. The authors tried to find an easily comprehensible way of presenting and explaining the very complex processes and mechanisms of biological radiation effects and carcinogenesis, displaying the physical primary processes and the mechanisms of the molecular radiation effects up to the effects of low-level radiation, and present results of comparative epidemiologic studies. This section has been given considerable space, in proportion to its significance. It also contains literature references for further reading, offering more insight and knowledge of aspects of special subject fields. The authors also present less known results and data and discuss them against the background of well-known research results and approaches. Apart from the purpose of presenting comprehensive information, the authors intend to give an impact for further thinking about the problems, and helpful tools for independent decisions and action on the basis of improved insight and assessment, and in this context particularly point to the problems induced by the Chernobyl reactor accident. (orig./MG) With 8 maps in appendix [de

  11. Spacelab Science Results Study

    Science.gov (United States)

    Naumann, R. J.; Lundquist, C. A.; Tandberg-Hanssen, E.; Horwitz, J. L.; Germany, G. A.; Cruise, J. F.; Lewis, M. L.; Murphy, K. L.

    2009-01-01

    Beginning with OSTA-1 in November 1981 and ending with Neurolab in March 1998, a total of 36 Shuttle missions carried various Spacelab components such as the Spacelab module, pallet, instrument pointing system, or mission peculiar experiment support structure. The experiments carried out during these flights included astrophysics, solar physics, plasma physics, atmospheric science, Earth observations, and a wide range of microgravity experiments in life sciences, biotechnology, materials science, and fluid physics which includes combustion and critical point phenomena. In all, some 764 experiments were conducted by investigators from the U.S., Europe, and Japan. The purpose of this Spacelab Science Results Study is to document the contributions made in each of the major research areas by giving a brief synopsis of the more significant experiments and an extensive list of the publications that were produced. We have also endeavored to show how these results impacted the existing body of knowledge, where they have spawned new fields, and if appropriate, where the knowledge they produced has been applied.

  12. Cumulative radiation effect

    International Nuclear Information System (INIS)

    Kirk, J.; Gray, W.M.; Watson, E.R.

    1977-01-01

    In five previous papers, the concept of Cumulative Radiation Effect (CRE) has been presented as a scale of accumulative sub-tolerance radiation damage, with a unique value of the CRE describing a specific level of radiation effect. Simple nomographic and tabular methods for the solution of practical problems in radiotherapy are now described. An essential feature of solving a CRE problem is firstly to present it in a concise and readily appreciated form, and, to do this, nomenclature has been introduced to describe schedules and regimes as compactly as possible. Simple algebraic equations have been derived to describe the CRE achieved by multi-schedule regimes. In these equations, the equivalence conditions existing at the junctions between schedules are not explicit and the equations are based on the CREs of the constituent schedules assessed individually without reference to their context in the regime as a whole. This independent evaluation of CREs for each schedule has resulted in a considerable simplification in the calculation of complex problems. The calculations are further simplified by the use of suitable tables and nomograms, so that the mathematics involved is reduced to simple arithmetical operations which require at the most the use of a slide rule but can be done by hand. The order of procedure in the presentation and calculation of CRE problems can be summarised in an evaluation procedure sheet. The resulting simple methods for solving practical problems of any complexity on the CRE-system are demonstrated by a number of examples. (author)

  13. Radiation effects in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Begay, F.; Rosen, L.; Petersen, D.F.; Mason, C.; Travis, B. [Los Alamos National Lab., NM (United States); Yazzie, A. [Navajo Nation, Window Rock, AZ (United States). Dept. of History; Isaac, M.C.P.; Seaborg, G.T. [Lawrence Berkeley National Lab., CA (United States); Leavitt, C.P. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Physics and Astronomy

    1999-04-01

    Although the Navajo possess substantial resource wealth-coal, gas, uranium, water-this potential wealth has been translated into limited permanent economic or political power. In fact, wealth or potential for wealth has often made the Navajo the victims of more powerful interests greedy for the assets under limited Navajo control. The primary focus for this education workshop on the radiation effects in the environment is to provide a forum where scientists from the nuclear science and technology community can share their knowledge toward the advancement and diffusion of nuclear science and technology issues for the Navajo public. The scientists will make an attempt to consider the following basic questions; what is science; what is mathematics; what is nuclear radiation? Seven papers are included in this report: Navajo view of radiation; Nuclear energy, national security and international stability; ABC`s of nuclear science; Nuclear medicine: 100 years in the making; Radon in the environment; Bicarbonate leaching of uranium; and Computational methods for subsurface flow and transport. The proceedings of this workshop will be used as a valuable reference materials in future workshops and K-14 classrooms in Navajo communities that need to improve basic understanding of nuclear science and technology issues. Results of the Begay-Stevens research has revealed the existence of strange and mysterious concepts in the Navajo Language of nature. With these research results Begay and Stevens prepared a lecture entitled The Physics of Laser Fusion in the Navajo language. This lecture has been delivered in numerous Navajo schools, and in universities and colleges in the US, Canada, and Alaska.

  14. Role of dust direct radiative effect on the tropical rainbelt over Middle East and North Africa: A high resolution AGCM study

    KAUST Repository

    Bangalath, Hamza Kunhu

    2015-04-25

    To investigate the influence of direct radiative effect of dust on the tropical summer rainbelt across the Middle East and North Africa (MENA), the present study utilizes the high resolution capability of an Atmospheric General Circulation Model (AGCM),the High Resolution Atmospheric Model (HiRAM). Ensembles of Atmospheric Model Inter-comparison Project (AMIP)-style simulations have been conducted with and without dust radiative impacts, to differentiate the influence of dust on the tropical rainbelt. The analysis focuses on summer season. The results highlight the role of dust induced responses in global and regional scale circulations in determining the strength and the latitudinal extent of the tropical rainbelt. A significant response in the strength and position of the local Hadley circulation is predicted in response to meridionally asymmetric distribution of dust and the corresponding radiative effects. Significant responses are also found in regional circulation features such as African Easterly Jet (AEJ) and West African Monsoon (WAM) circulation. Consistent with these dynamic responses at various scales, the tropical rainbelt across MENA strengthens and shifts northward. Importantly, the summer precipitation over the semi-arid strip south of Sahara, including Sahel, increases up to 20%. As this region is characterized by the “Sahel drought" , the predicted precipitation sensitivity to the dust loading over this region has a wide-range of socioeconomic implications. Overall, the study demonstrates the extreme importance of incorporating dust radiative effects and the corresponding circulation responses at various scales, in the simulations and future projections of this region\\'s climate.

  15. The status of the seventh report in the series Biological Effects of Ionizing Radiations and a revised dosimetry for the Radiation Effects Research Foundation's A-bomb studies

    International Nuclear Information System (INIS)

    Douple, Evan; Jostes, Rick

    2002-01-01

    Results of a National Academies workshop and feasibility study led US Governmental agencies to request the Board on Radiation Effects Research of the National Research Council to commence a risk assessment study in 1998 as the seventh report in the series Biological Effects of Ionizing Radiations (BEIR VII). Originally targeted for completion in the autumn of 2001, the study Potential Health Effects of Exposure to Low Dose, Low-LET Ionizing Radiation was extended until the autumn of 2003 at the request of the sponsors. Two factors contributing to this decision are discussed: a revised dosimetry to update DS86 for the Radiation Effects Research Foundation's A-bomb-survivor studies and the potential for new information to become available from low-dose studies that are under way. Epidemiological and biological data since BEIR V are being considered by a BEIR VII committee composed of 17 members. The committee's statement of task is reviewed along with the major recommendations of the recent National Research Council report on the status of DS86 - recommendations that are being implemented by US and Japan dosimetry working groups. (author)

  16. Using nitrogen-14 nuclear quadrupole resonance and electric field gradient information for the study of radiation effects

    International Nuclear Information System (INIS)

    Iselin, L.H.

    1995-12-01

    Nitrogen-14 nuclear quadrupole resonance (NQR) was used in an attempt to detect the effects of ionizing radiation on organic material. Previously reported resonances for urea were detected at 2,913.32 ± 0.01 kHz and 2,347.88 ± 0.08 kHz with associated T 2 * values 780 ± 20 micros and 523 ± 24 micros, respectively. The previously unreported ν - line for urea-d 4 was detected at 2,381 ± 0.04 Khz and used to determine accurately for the first time the values for the nuclear quadrupole coupling constant χ (3,548.74 ± 0.03 kHz) and the asymmetry parameter η (0.31571 ± 0.00007) for urea-d 4 . The inverse linewidth parameter T 2 * for ν + was measured at 928 ± 23 micros and for ν - at 721 ± 12 micros. Townes and Dailey analysis was performed and urea-d 4 exhibits a 0.004 increase in lone pair electronic density and a slight decrease in N-H bond electronic density, as compared to urea, probably due to the mass difference. A relationship is proposed, referred to as NQR linewidth analysis, between the dynamic spin relaxation times T 2 and T 2 * and the widths of the distributions of the NQR parameters. Linewidth analysis is presented as a tool for possible use in future NQR work in all area, not just radiation effects. This relationship is tested using sodium nitrite T 2 and T 2 * values for ν - and ν - as a function of temperature

  17. Radiation effects in silicate glasses

    International Nuclear Information System (INIS)

    Bibler, N.E.; Howitt, D.G.

    1988-01-01

    The study of radiation effects in complex silicate glasses has received renewed attention because of their use in special applications such as high level nuclear waste immobilization and fiber optics. Radiation changes the properties of these glasses by altering their electronic and atomic configurations. These alterations or defects may cause dilatations or microscopic phase changes along with absorption centers that limit the optical application of the glasses. Atomic displacements induced in the already disordered structure of the glasses may affect their use where heavy irradiating particles such as alpha particles, alpha recoils, fission fragments, or accelerated ions are present. Large changes (up to 1%) in density may result. In some cases the radiation damage may be severe enough to affect the durability of the glass in aqueous solutions. In the paper, the authors review the literature concerning radiation effects on density, durability, stored energy, microstructure and optical properties of silicate glasses. Both simple glasses and complex glasses used for immobilization of nuclear waste are considered

  18. An analytical method for estimating the 14N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

    International Nuclear Information System (INIS)

    Iselin, L.H.

    1992-01-01

    The use of 14 N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing 14 N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The 14 N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation

  19. An analytical method for estimating the 14N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

    Energy Technology Data Exchange (ETDEWEB)

    Iselin, Louis Henry [Univ. of Florida, Gainesville, FL (United States)

    1992-01-01

    The use of 14N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing 14N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The 14N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation.

  20. Radiation effects on microelectronics

    International Nuclear Information System (INIS)

    Gover, J.E.

    1987-01-01

    Applications of radiation-hardened microelectronics in nuclear power systems include (a) light water reactor (LWR) containment building, postaccident instrumentation that can operate through the beta and gamma radiation released in a design basis loss-of-coolant accident; (b) advanced LWR instrumentation and control systems employing distributed digital integrated circuit (IC) technology to achieve a high degree of artificial intelligence and thereby reduce the probability of operator error under accident conditions; (c) instrumentation, command, control and communication systems for space nuclear power applications that must operate during the neutron and gamma-ray core leakage environments as well as the background electron, proton, and heavy charged particle environments of space; and (d) robotics systems designed for the described functions. Advanced microelectronics offer advantages in cost and reliability over alternative approaches to instrumentation and control. No semiconductor technology is hard to all classes of radiation effects phenomena. As the effects have become better understood, however, significant progress has been made in hardening IC technology. Application of hardened microelectronics to nuclear power systems has lagged military applications because of the limited market potential of hardened instruments and numerous institutional impediments

  1. Nationwide survey on pediatric CT among children of public health and school nurses to examine a possibility for a follow-up study on radiation effects

    International Nuclear Information System (INIS)

    Ono, K.; Ban, N.; Ojima, M.; Yoshinaga, S.; Akahane, K.; Fujii, K.; Toyota, M.; Hamada, F.; Kouriyama, C.; Akiba, S.; Kunugita, N.; Shimada, Y.; Kai, M.

    2011-01-01

    A nationwide survey was conducted in Japan on paediatric CT among children of public health and school nurses to examine a possibility for a follow-up study on radiation effects. A survey questionnaire was sent out to 3173 public primary and junior high schools and 317 public health centres during October to December in 2009. According to the collected responses, 410 (16.2 %) children received the CT scans and the total number of CT scans was 585. Most of respondents expressed a high interest in radiation health effects and an intent to participate in the epidemiological study that will follow-up the health conditions of children. This study provides information to discuss the feasibility of the epidemiological study on health effects in children who received CT scans. (authors)

  2. Annual report of Radiation Effects Research Foundation

    International Nuclear Information System (INIS)

    1980-01-01

    The Radiation Effects Research Foundation was established in April, 1975, as a private nonprofit Japanese Foundation supported equally by the Government of Japan through the Ministry of Health and Welfare, and the Government of the United States through the National Academy of Sciences under contract with the Energy Research and Development Administration. First, the messages from the chairman and the vice-chairman are described. In the annual report, the review of ABCC-RERF studies of atomic bomb survivors, the summary of research activities, the research projects, the technical report abstracts, the research papers published in Japanese and foreign journals, and the oral presentation and lectures, all from April 1, 1978, to March 31, 1979, are reported. Also the report from the Secretariat and the appendixes are given. The surveys and researches carried out in Hiroshima and Nagasaki have offered very valuable informations to the atomic bomb survivors. Many fears were eliminated, medical interests were given to the serious effects of the exposure to atomic bombs, and many things concerning the cancer induced by radiation were elucidated. The knowledges obtained will save many human lives in future by utilizing them for setting up the health and safety standard in the case of handling ionizing radiation. The progress in researches such as life span study, adult health study, pathology study, genetics program, special cancer program and so on is reported. (Kako, I.)

  3. Sensitivity of mesoscale modeling of smoke direct radiative effect to the emission inventory: a case study in northern sub-Saharan African region

    International Nuclear Information System (INIS)

    Zhang, Feng; Wang, Jun; Yang, Zhifeng; Ge, Cui; Ichoku, Charles; Hyer, Edward J; Da Silva, Arlindo; Su, Shenjian; Zhang, Xiaoyang; Kondragunta, Shobha; Kaiser, Johannes W; Wiedinmyer, Christine

    2014-01-01

    An ensemble approach is used to examine the sensitivity of smoke loading and smoke direct radiative effect in the atmosphere to uncertainties in smoke emission estimates. Seven different fire emission inventories are applied independently to WRF-Chem model (v3.5) with the same model configuration (excluding dust and other emission sources) over the northern sub-Saharan African (NSSA) biomass-burning region. Results for November and February 2010 are analyzed, respectively representing the start and end of the biomass burning season in the study region. For February 2010, estimates of total smoke emission vary by a factor of 12, but only differences by factors of 7 or less are found in the simulated regional (15°W–42°E, 13°S–17°N) and monthly averages of column PM 2.5 loading, surface PM 2.5 concentration, aerosol optical depth (AOD), smoke radiative forcing at the top-of-atmosphere and at the surface, and air temperature at 2 m and at 700 hPa. The smaller differences in these simulated variables may reflect the atmospheric diffusion and deposition effects to dampen the large difference in smoke emissions that are highly concentrated in areas much smaller than the regional domain of the study. Indeed, at the local scale, large differences (up to a factor of 33) persist in simulated smoke-related variables and radiative effects including semi-direct effect. Similar results are also found for November 2010, despite differences in meteorology and fire activity. Hence, biomass burning emission uncertainties have a large influence on the reliability of model simulations of atmospheric aerosol loading, transport, and radiative impacts, and this influence is largest at local and hourly-to-daily scales. Accurate quantification of smoke effects on regional climate and air quality requires further reduction of emission uncertainties, particularly for regions of high fire concentrations such as NSSA. (paper)

  4. Physics of radiation effects in crystals

    CERN Document Server

    Johnson, RA

    1986-01-01

    ``Physics of Radiation Effects in Crystals'' is presented in two parts. The first part covers the general background and theory of radiation effects in crystals, including the theory describing the generation of crystal lattice defects by radiation, the kinetic approach to the study of the disposition of these defects and the effects of the diffusion of these defects on alloy compositions and phases. Specific problems of current interest are treated in the second part and include anisotropic dimensional changes in x-uranium, zirconium and graphite, acceleration of thermal creep in reactor ma

  5. Radiation effects on living systems

    International Nuclear Information System (INIS)

    Hawley, N.J.

    1980-10-01

    This bibliography includes papers and reports by Atomic Energy of Canada Limited scientists concerning radiation effects on living systems. It is divided into three sections: Radiobiology, Radiation Biochemistry and Radiation Chemistry. (auth)

  6. The transient radiation effects and hardness of programmed device

    International Nuclear Information System (INIS)

    Du Chuanhua; Xu Xianguo; Zhao Hailin

    2014-01-01

    A review and summary of research and development in the investigation of transient ionizing radiation effects in device and cirviut is presented. The transient ionizing radiation effects in two type of programmed device, that's 32 bit Microcontroller and antifuse FPGA, were studied. The expeiment test data indicate: The transient ionizing radiation effects of 32 bit Microcontroller manifested self-motion restart and Latchup, the Latchup threshold was 5 × 10"7 Gy (Si)/s. The transient ionizing radiation effects of FPGA was reset, no Latchup. The relationship of circuit effects to physical mechanisms was analized. A new method of hardness in circiut design was put forward. (authors)

  7. Gamma and electron radiation effects on straw

    International Nuclear Information System (INIS)

    Leonhardt, J.W.; Baer, M.; Huebner, G.

    1983-01-01

    Gamma and electron radiation effects on wheat straw, oat straw, barley straw and rye straw are reported. In vitro and in vivo studies show that the digestibility of these agricultural rough materials can be increased up to 80% and more at high doses. The increase of the digestibility is connected with a depolymerisation of cellulose and hemicellulose. (author)

  8. Physico-chemical studies of radiation effects in cells. Progress report, February 15, 1982-February 14, 1983

    International Nuclear Information System (INIS)

    Powers, E.L.

    1982-01-01

    Progress in studies investigating the chemical mechanisms involved in radiation-induced cellular damage is reported. Three organisms currently being tested are Bacillus megaterium, Bacillus subtilis, and Escherichia coli, silver and mercury have been used as radiosensitizers, and their interaction with DNA studied

  9. DOE life-span radiation effects studies in experimental animals at University of Utah Division of Radiobiology

    International Nuclear Information System (INIS)

    Wrenn, M.E.; Taylor, G.N.; Stevens, W.

    1986-01-01

    The Radiobiology Laboratory at the University of Utah compared the long-term biological effects of 226 Ra and 239 Pu in adult beagles. The program includes the investigation of other radionuclides. More recently, groups of juvenile and aged beagles were added to the study to investigate the influence of age at exposure. These studies involved single intravenous injection of radionuclides to small groups of beagles, in graded doses from levels at which no effects were expected up to levels where a 100% incidence of bone tumors was sometimes found. Some of the principal effects were bone tumors, fractures, and other skeletal alterations observed radiographically and histologically; emphasis was placed on the detection of precancerous changes, hematological changes, and changes related to aging. Emphasis was also placed on metabolic and autoradiographic studies necessary for good radiation dosimetry

  10. Study of the radiation effects on nucleic acids and related compounds. Annual progress report, November 15, 1977--November 14, 1978

    International Nuclear Information System (INIS)

    Wang, S.Y.

    1978-07-01

    Acquisition of information on molecular biology involves four stages: establishment of procedures for the separation, isolation, and characterization of radiation products of nucleic acid bases, nucleosides, etc.; development of methods for the synthesis of these products once they are identified so that a constant supply in milligram to gram quantities is available for the studies in stages 3 and 4; examination of the apparent biological effects of each product in vitro and in vivo; and study of the molecular mechanism related to an observed biological phenomenon. In view of the difficulties experienced in this area of research and this deliberate and careful investigative approach, it was generally believed that progress toward our final goal would be rather prolonged. Yet the elucidation of a molecular mechanism by which ionizing radiation induces mutation in vivo is very near at hand. Further progress has been made in the separation and isolation of three hydroperoxy derivatives of thymidine. One communication has appeared and another has been submitted for publication. The former reports the efficient stereospecific synthesis of cis-pyrimidine glycols and the latter describes the study of mutagenicity and toxicity of seven radiation products of thymine and thymidine using Ames Salmonella test. Also, a quantitative study of the reversion of cytosine N(3)-oxide, a hydroperoxidation product induced by 6-TOOH, to cytosine has been carried out

  11. Study of the radiation effects on nucleic acids and related compounds. Annual progress report, August 15, 1974--August 14, 1975

    International Nuclear Information System (INIS)

    Wang, S.Y.

    1975-01-01

    Interest is being centered on the chemical and physical nature of radiation-induced lesions to nucleic acids and their components. These investigations have revealed the enormous complexity of chemical events in these systems and the possible degradation of nucleic acids by strand breakage. Therefore, work in the ionizing radiation of DNA and its components has proceeded along a dual course. For chemical studies, our prime concern is the stepwise isolation and identification of the radiation products of derivatives of pyrimidines and the study of the actual mechanisms of their formation. For biological studies, H. influenzae cells, the Chinese hamster V79B-1 cell line, and the Dunn osteosarcoma lung colony system were used. During the last year, the method of synthesis of 5-hydroperoxymethyluracil (T/sub α/OOH) was greatly improved. Large-scale preparation of 5-hydroxy-6-hydroperoxy-5,6-dihydrothymine (T 6 OOH) were carried out in order to study the action of T 6 OOH on neighboring bases, glycosidic bond-breakage, cell mutagenesis, chromosomal aberrations, and possible synergistic effects on x radiation. These results allow one to relate radiobiological effects with radiation chemical changes in DNA

  12. Electron spin resonance studies of radiation effects. Final report, 1964-1979 (including annual progress reports for 1978 and 1979)

    International Nuclear Information System (INIS)

    Rogers, M.T.

    1979-07-01

    The discovery of new free radicals, largely in irradiated single crystals of nonmetallic solids, and the determination of the molecular and electronic structures of these paramagnetic species by electron spin resonance (ESR) spectroscopy, have been carried out using a wide variety of organic and inorganic materials. The mechanisms of production of radicals in solids, their motions, and their reactions have been investigated and some applicable general principles deduced. Emphasis has been on aliphatic free radicals from irradiated carboxylic acids and amides and their halogen-substituted derivatives, organometallic radicals and substituted cyclic hydrocarbon radicals; inorganic radicals studied include V centers, hypervalent radicals and electron adducts. Extensive investigations of paramagnetic transition metal complexes, particularly cyanides and fluorides, have been made. In all cases quantum mechanical calculations have been employed as far as possible in interpreting the data. An improved method for analyzing experimental ESR spectra of single crystals has been developed and a number of crystal structures have been determined to supplement the ESR studies. Applications of nuclear quadrupole resonance spectroscopy to the study of structure and bonding in inorganic solids have been made and a method for using nuclear magnetic relaxation data for estimating quadrupole coupling constants in liquids has been developed

  13. Life-span radiation effects studies in prenatally and postnatally exposed beagle dogs at Colorado State University

    International Nuclear Information System (INIS)

    Benjamin, S.A.; Lee, A.C.; Angleton, G.M.; Jaenke, R.S.; Saunders, W.J.; Miller, G.K.; Brewster, R.D.

    1986-01-01

    The lifetime hazards associated with exposure to ionizing radiation during development are studied in 1680 beagle dogs given whole-body exposures to 60 Co gamma radiation. Eight groups of 120 dogs each received 20-R or 100-R exposures at 8, 28, or 55 days postcoitus (dpc) or at 2 days postpartum (dpp). In addition, exposures of 100 R were given to 120 dogs at 70 dpp and to 240 dogs at 365 dpp. An additional 360 dogs were sham exposed. Smaller groups of dogs were used to identify organs and tissues of particular sensitivity to radiation injury during development and to evaluate mechanisms of radiation injury. The research is concerned primarily with evaluating the role of age at exposure as a factor influencing response to radiation injury. As of December 31, 1982, of the 1680 dogs, 1058 were dead. Survivors ranged from 9.9 to 15 years of age. Through 10 years of age, no differences in survival were evident in any exposure groups. A variety of clinical, pathophysiologic, and pathologic responses have been studied. Irradiation during development has been found to be associated with abnormalities of skeletal, dental, and central nervous system development. Irradiation during ocular development has induced dysplastic and atrophic retinal lesions. Perinatal irradiation of the kidney has resulted in dysplasia, and, in animals receiving higher doses, significant chronic renal disease. The thymus gland, particularly thymic epithelium, has been found to be highly radiosensitive during fetal development

  14. Study of the radiation effects on nucleic acids and related compounds. Progress report, August 15, 1976--November 14, 1977

    International Nuclear Information System (INIS)

    Wang, S.Y.

    1977-08-01

    The effects of ionizing radiation on nucleic acids and components were studied in vitro. Our approach involves four levels of operation and progress is being made at each stage. First, procedures were established to separate and purify three reactive radiation products from thymidine. Second, improved methods of synthesizing trans-glycols of pyrimidines were developed, and a new method for the stereospecific synthesis of cis-glycol of pyrimidines was realized. Thirdly, the Ames Salmonella test was used to determine the mutagenicity of the radiation products and the reactive ones from thymine and thymidine were found to be highly mutagenic. Therefore, all radiation products should be considered potential human health hazards and should be screened when they can be purified and synthesized. In the fourth stage, the reaction of each nucleic-acid base with Cu ++ and cis-5,6-dihydro-6-hydroperoxy-5-hydroxythymine (6-TOOH) was studied in order to further our understanding of the molecular mechanisms of radiation mutagenesis. The presence of Cu ++ was shown to be necessary for the effective mutagenic activity of 6-TOOH in the H. influenzae transformation assay. These findings provide fundamental information about the possible health hazards of ionizing radiation and will be useful in designing methods to protect against and repair radiation damage, which may be mutagenic and carcinogenic

  15. Study of the gamma radiation effect on lincomycin by two techniques thermal analysis and fourier transform infrared (FTIR)

    International Nuclear Information System (INIS)

    Al-Zier, A.; Al-Kassiri, H.; Al Aji, Z.

    1999-02-01

    Sample of Lincomycin were irradiated by means of gamma radiation ( 60 Co) at dose rate ca. (408 kGy/h) in the range (3, 5, 15, 20)kGy in presence of air. Samples were investigated using two techniques: Thermal analysis (Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG)) and Fourier Transform Infrared (FTIR). DSC purity study, which depends on Vant Hof equation, showed that the purity of Lincomycin reduced by means of gamma radiation. The purity of theses samples decreased by increasing the dose, and the purity of lincomycin was still above (99%) at dose (10 kGy). To follow up this effects, (FTIR) spectrums of these sample were recorded before and after irradiation. The two peaks at (1500 - 1750 Cm -1 ) which belong to amide group, and the peak at (1050 - 1100 Cm -1 ) which belongs to the S-C groups have reduced. (author)

  16. Study of the gamma radiation effect on the lincomycin by two techniques thermal analysis and fourier transform infrared (FTIR)

    International Nuclear Information System (INIS)

    Al-Zier, A.; Al-Kassiri, H.

    1999-01-01

    Sample of Lincomycin were irradiated by means of gamma radiation ( 60 Co) at dose rate ca. (408 kGy/h) in the range (3, 5, 15, 20)kGy in presence of air. Samples were investigated using two techniques: Thermal analysis (Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG)) and Fourier Transform Infrared (FTIR). DSC purity study, which depends on Vant Hof equation, showed that the purity of Lincomycin reduced by means of gamma radiation. The purity of theses samples decreased by increasing the dose, and the purity of lincomycin was still above (99%) at dose (10 kGy). To follow up this effects, (FTIR) spectrums of these sample were recorded before and after irradiation. The two peaks at (1500 - 1750 Cm -1 ) which belong to amide group, and the peak at (1050 - 1100 Cm -1 ) which belongs to the S-C groups have reduced. (author)

  17. Study of 60 Co gamma radiation effects on the biochemical, biological and immunological properties of the Bothrops jararaca venom

    International Nuclear Information System (INIS)

    Guarnieri, M.C.

    1992-01-01

    Gamma radiation, by including different modifications on the toxic, enzymatic and immunological activities of proteins, could be an useful implement for detoxification of snake venoms. The present work was done to study the mechanism of action and effects of gamma rays on the Bothrops jararaca venom, determining the radiation dose that attenuates the toxic and enzymatic activities maintaining the immunological properties of venom, and also the most important free radicals on this process. The results of immuno diffusion, immunoblotting, immunoprecipitation, immunization of mice and rabbits, and neutralization tests, showed the maintenance of antigenic and immunogenic properties and decrease of neutralizing capacity of antibodies induced by 3,000 and 4,000 Gy irradiated venom. Since the immunological properties were the most radioresistant, it was possible to determine the dose of 2,000 Gy, as the ideal radiation dose in the treatment of venoms aiming the improvement of the immunization schedule to obtain bothropic antisera. (author). 164 refs, 19 tabs, 54 figs

  18. Radiation effects on testes. XI. Studies on glycogen and its metabolizing enzymes following radiation-induced atrophy

    International Nuclear Information System (INIS)

    Gupta, G.S.; Bawa, S.R.

    1977-01-01

    Effect of radiation on enzymes of carbohydrate metabolism has been studied. It is observed that hexokinase of testis is highly sensitive to radiation damage. Reduced hexokinase activity seems to be related to those parts of the testis (spermatocytes and spermatids) which depend upon glucose for their functioning. Radiation-induced atrophic testis is rich in glycogen content. The observations on the inhibition of gluocose-6-phosphatase and phosphorylase may explain the higher levels of the polysaccharide although a possibility of enhanced glycogenesis due to the activation of glycogen synthetase has also been suggested. The presence of glucose-6-phosphate isomerase and glycogen in atrophied testis in 11-month-treated rats indicate the higher glycolytic activity with hyperplastic testicular interstitium. The results suggest that the accumulated glycogen is acting as a reserve substrate in nongerminal cells

  19. Physico-chemical studies of radiation effects in cells. Progress report, February 15, 1984-February 14, 1985

    International Nuclear Information System (INIS)

    Powers, E.L.

    1985-01-01

    The radioprotective effects of Hg ++ were investigated in Staphylococcus aureus and Pseudomonas aeruginosa bacteria having very different gc ratios in their DNA. A protective effect is seen in both with first order curves or at least in the k/sub L/ region of the breakpoints. However, it is curious that there is a distinct difference in the metal-free N 2 baseline of Staphylococcus aureus compared to its EtOH metal-free N 2 response while with Pseudomonas aeruginosa both the metal-free N 2 baseline and its EtOH metal-free results are similar. In related studies a new radioprotective substance was evaluated in bacterial systems. Results showed that, in the presence of Rh(NH 3 ) 3 C/ 3 , the anoxic cell shows greater sensitivity than the oxygenated cell. This compound has considerable therapeutic promise providing it acts the same on mammalian cells. 8 refs., 6 figs. (DT)

  20. Studies of thermal and radiation effects on water-rock systems related to envisaged isolation of high level radioactive wastes in crystalline formations of the Ukrainian shield (Ukraine)

    International Nuclear Information System (INIS)

    Litovchenko, A.; Kalinichenko, E.; Ivanitsky, V.; Bagmut, M.; Plastinina, M.; Zlobenko, B.

    2000-01-01

    In this work there are presented the general data on the study of thermal and radiation effects in minerals separated from rocks of the Ukrainian shield. These minerals (quartz, feldspar, amphiboles, apatite, biotite, kaolinite, etc.), exposed by doses 10 4 , 10 6 , 10 8 Gy by Co 60 source, were studied by a complex of physical methods. Special attention was given to the study of radiation defects formation (electron-hole paramagnetic centres, OH- groups destruction, changes in a charge state of ions) in a mineral structure. The mentioned radiation defects were used in the extrapolation method. The connection between structural peculiarities of minerals (containing uranium and thorium) and processes of their metamyctization are considered. It is demonstrated that the minerals, which have large channels or interlayer spaces in their structure, as a rule, are not metamyct. Using the spectroscopic methods of the extrapolation it is shown that the crystalline massifs, which do not have detectable amounts of hydroxyl containing minerals (biotite, amphibole, etc.) and ions Fe 2- , are perspective for long-lived radioactive wastes (RAW) dumping. As it follows from obtained results, the rocks, containing minerals with OH- groups and gas-liquid inclusions, should be considered as the 'mineral-water' system. (author)

  1. Radiation effects in the polycarbonate of bisphenol-A. Thermoluminescence electron spin resonance and charged particle track studies

    International Nuclear Information System (INIS)

    Edmonds, E.A.

    1978-09-01

    A detailed investigation is presented of the thermoluminescence observable above room temperature from the polycarbonate of bisphenol-A after its exposure to different radiations. A correlation study is described by which features of the complex thermoluminescence glow curve from a commercial grade of the polycarbonate of bisphenol-A are related to the etchability of charged particle damage trails and the radiogenic ESR signal. A model is presented whereby the etchability of charged particle damage trails is associated with chain scission caused by the high local dose of radiation in the vicinity of the trajectories of charged particles. Methods by which activation constants controlling the thermoluminescence glow curve can be evaluated are discussed and results are presented. It is concluded that glow peaks associated with the ESR signal or enhanced etchability are related to small-scale motions in the molecular matrix of the polycarbonate of bisphenol-A. These motions are thermally activated in accord with the simple Boltzmann relation usually incorporated into theories of thermoluminescence. Another component glow peak of the thermoluminescence glow curve is shown to be associated with the glass-rubber transition in the polycarbonate of bisphenol-A. Different features of the thermoluminescence glow curve can be related to relaxations of the polymer matrix and decomposition of the matrix. It is confirmed that the dominant bulk effect of radiation in the polycarbonate of bisphenol-A exposed to large doses of radiation is chain scission. (author)

  2. Ionizing radiation effect study by electron beam on ultra high molecular weight polyethylene virgin and recycled industrial

    International Nuclear Information System (INIS)

    Rosario, Salmo Cordeiro do

    2006-01-01

    Ultra High Molecular Weight Polyethylene (UHMWPE) is an engineering plastic which has several applications, chiefly, in specific areas of the industry and medicine. UHMWPE can be even for other applications such as: port fenders, current guide, bucket coating, silos and gutters, plugs, pulleys and surgical prosthesis. This range of applications is due to the excellent technical characteristics that this material owns, such as; high resistance to wear, high resistance to impact, anti-adherence, non toxic, excellent chemical resistance, low specific weight, easy mill processing, and high resistance to fatigue. The UHMWPE type used in this work were UTEC 3041 and UTEC 6541 of the Braskem. The recycling process of UHMWPE raised much interest, because the utilization of this raw material grew over 600% in the last decade, becoming one of the most used engineering plastics for attainment of mill processed parts after polyamide. As the utilization of this polymer in the manufacturing of parts for machinery has grown, its waste is very big, because the rest of this material is thrown out, usually not being reused. The goal of this work is to recycle the UHMWPE UTEC 3041 and study the properties of this recycled and virgin material and compare the results between both with these materials submitted to different radiation dose. (author)

  3. Advancing Solar Irradiance Measurement for Climate-Related Studies: Accurate Constraint on Direct Aerosol Radiative Effect (DARE)

    Science.gov (United States)

    Tsay, Si-Chee; Ji, Q. Jack

    2011-01-01

    Earth's climate is driven primarily by solar radiation. As summarized in various IPCC reports, the global average of radiative forcing for different agents and mechanisms, such as aerosols or CO2 doubling, is in the range of a few W/sq m. However, when solar irradiance is measured by broadband radiometers, such as the fleet of Eppley Precision Solar Pyranometers (PSP) and equivalent instrumentation employed worldwide, the measurement uncertainty is larger than 2% (e.g., WMO specification of pyranometer, 2008). Thus, out of the approx. 184 W/sq m (approx.263 W/sq m if cloud-free) surface solar insolation (Trenberth et al. 2009), the measurement uncertainty is greater than +/-3.6 W/sq m, overwhelming the climate change signals. To discern these signals, less than a 1 % measurement uncertainty is required and is currently achievable only by means of a newly developed methodology employing a modified PSP-like pyranometer and an updated calibration equation to account for its thermal effects (li and Tsay, 2010). In this talk, we will show that some auxiliary measurements, such as those from a collocated pyrgeometer or air temperature sensors, can help correct historical datasets. Additionally, we will also demonstrate that a pyrheliometer is not free of the thermal effect; therefore, comparing to a high cost yet still not thermal-effect-free "direct + diffuse" approach in measuring surface solar irradiance, our new method is more economical, and more likely to be suitable for correcting a wide variety of historical datasets. Modeling simulations will be presented that a corrected solar irradiance measurement has a significant impact on aerosol forcing, and thus plays an important role in climate studies.

  4. Studies on the health effects of a-bomb radiation exposure appeared in health examinations of adult survivors by the Radiation Effects Research Foundation

    International Nuclear Information System (INIS)

    Yamada, Michiko

    2006-01-01

    The Research Foundation has conducted the health examinations in the title since 1958, based on which studies of a cohort type have been performed, and their results at present are summarized in this paper. Subjects have included a cohort of about 120000 cases in total. They have been those 4993 initial cases (the center group) exposed to estimated radiation doses of 4 -6 Gy within the distance of 2 km from the hypocenter and with acute exposure symptoms either in Hiroshima or Nagasaki, and 19961 cases (exposed ones within 2 km from the hypocenter but without the symptoms, exposed residents in the city 3 km far from the hypocenter, or ones absent in the city at explosion) matched to the above center group in the city, age and sex. Lower statures and weights are noted in some of the center group who were in growing ages at exposure. Increases of prevalence or incidence rate are suggested in malignant tumors, diseases of the thyroid and parathyroid, uterine myoma, chronic liver diseases, cataract, circulatory diseases, abnormal hemoglobin value, and psychological states. Relative risk at 1 Gy for incidence of non-cancer diseases is calculated and presented. Results are not always consistent with those of such population exposed to <6 Gy as that of Chernobyl Accident, of radiation technologist and of people accidentally exposed to environmental radiation. The Foundation is to continue the study and more profound results of radiation effects are expected to be obtainable. (T.I)

  5. Magnetohydrodynamic and thermal radiation effects on the boundary-layer flow due to a moving extensible surface with the velocity slip model: A comparative study of four nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Aly, Emad H., E-mail: efarag@uj.edu.sa [Department of Mathematics, Faculty of Science, University of Jeddah, Jeddah 21589 (Saudi Arabia); Department of Mathematics, Faculty of Education, Ain Shams University, Roxy, Cairo 11757 (Egypt); Sayed, Hamed M. [Department of Mathematics, Faculty of Education, Ain Shams University, Roxy, Cairo 11757 (Egypt); Department of Mathematics, Faculty of Sciences, Taibah University, Yanbu (Saudi Arabia)

    2017-01-15

    In the current work, we investigated effects of the velocity slip for the flow and heat transfer of four nanofluids over a non-linear stretching sheet taking into account the thermal radiation and magnetic field in presence of the effective electrical conductivity. The governing partial differential equations were transformed into a set of nonlinear ordinary differential equation using similarity transformations before being solved numerically by the Chebyshev pseudospectral differentiation matrix (ChPDM). It was found that the investigated parameters affect remarkably on the nanofluid stream function for the whole investigated nanoparticles. In addition, velocity and skin friction profiles of the four investigated nanofluids decreases and increases, respectively, with the increase of the magnetic parameter, first-order and second-order velocity slips. Further, the flow velocity, surface shear stress and temperature are strongly influenced on applying the velocity slip model, where lower values of the second-order imply higher surface heat flux and thereby making the fluid warmer. - Highlights: • A comparative study for four nanoparticles with MHD and thermal radiation effects was studied. • The effective electrical conductivity is mandatory; otherwise a spurious physical sight will be gained. • The investigated parameters affect remarkably on the nanofluids' flow. • The flow velocity, surface shear stress and temperature are strongly influenced by the slip model. • Lower values of the second-order imply higher surface heat flux and thereby making the fluid warmer.

  6. Radiation effects at ISABELLE

    International Nuclear Information System (INIS)

    Sanger, P.A.; Danby, G.T.

    1975-01-01

    Shielding, radiation damage, and radiation heating at the planned ISABELLE storage rings were considered. Radiation shielding studies were reviewed and were found to be adequate for present day dosage limits. Radiation damage could be encountered in some extreme cases, but is not expected to limit the performance of the superconducting magnets. Experiments to study the effect of radiation heating on actual magnets are recommended

  7. Three-dimensional, two-species magnetohydrodynamic studies of the early time behaviors of the Combined Release and Radiation Effects Satellite G2 barium release

    International Nuclear Information System (INIS)

    Xie, Lianghai; Li, Lei; Wang, Jingdong; Zhang, Yiteng

    2014-01-01

    We present a three-dimensional, two-species (Ba + and H + ) MHD model to study the early time behaviors of a barium release at about 1 R E like Combined Release and Radiation Effects Satellite G2, with emphasis placed on the three-dimensional evolution of the barium cloud and its effects on the ambient plasma environment. We find that the perturbations caused by the cloud are the combined results of the initial injection, the radial expansion, and the diamagnetic effect and propagate as fast MHD waves in the magnetosphere. In return, the transverse expansion and the cross-B motion of barium ions are constrained by the magnetic force, which lead to a field-aligned striation of ions and the decoupling of these ions from the neutrals. Our simulation shows the formation and collapse of the diamagnetic cavity in the barium cloud. The estimated time scale for the cavity evolution might be much shorter if photoionization time scale and field aligned expansion of barium ions are considered. In addition, our two species MHD simulation also finds the snowplow effect resulting from the momentum coupling between barium ions and background H + , which creates density hole and bumps in the background H + when barium ions expanding along the magnetic field lines

  8. Characterization of ionizing radiation effects in MOS structures by study of bipolar operation; Caracterisation des effets induits par irradiations ionisantes dans des structures MOS a partir de leur fonctionnement en regime bipolaire

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtiar, H. [Univ. Teknologi Malaysia, Dept. of Physics, Johor (Malaysia); Picard, C.; Brisset, C. [CEA Saclay, Lab. d' Electronique et de Technologie de l' Informatique, LETI, 91 - Gif-sur-Yvette (France); Bakhtiar, H.; Hoffmann, A.; Charles, J.P. [Metz Univ., LICM-CLOES-Supelec, 57 (France)

    1999-07-01

    This work presents an original method to characterize radiation effects of micronic transistors. The characterization includes a study of the transistor substrate-drain junction and current gain variation of the bipolar transistor (drain-substrate-source as emitter-base-collector) for different gate voltages. (author000.

  9. Activities of the National Academy of Sciences in relation to the Radiation Effects Research Foundation. Annual performance report, June 1, 1991--May 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Edington, C.W.

    1992-06-01

    This progress report relates progress in the various research projects evaluating the late health effects, both somatic and genetic, resulting from radiation exposure of the survivors of the atomic bombs at Hiroshima and Nagasaki, Japan. Considerable progress has been made in the collection and utilization of the various epidemiological data bases. These include the Life Span Study, (LSS) cohort, the Adult Health Study (AHS) cohort, the In Utero cohort, the leukemia registry and the F-1 Study population. Important progress has been made in using RERF Tumor and Tissue Registry records for evaluation of cancer incidence and radiation risk estimates for comparison with cancer mortality and risk in the LSS cohort. At the present time, a manuscript on the incidence of solid tumors (1950-1987) is undergoing internal and external review for publication as an RERF Technical report (TR) and for publication in a peer-reviewed scientific journal. In addition, manuscripts are in preparation on (1) a comprehensive report on the incidence of hematological cancers, including analysis of leukemia by cell type (1950-1987), (2) a general description of Tumor Registry operations and (3) a comparison of incidence- and mortality-based estimates of radiation risk in the LSS cohort.

  10. Radiation effects in metals

    International Nuclear Information System (INIS)

    Leteurtre Jean.

    1978-01-01

    The current understanding of radiation damage in metals is reviewed, simplifying the actual complexity of the effects by considering some aspects separately. The production of point defects in metals, the primary damage state are first studied. The second part of the lecture is devoted to the evolution of this primary damage state as a function of temperature and dose: the steady state concentration of point defects, the nucleation of secondary defects and their growth are successively considered

  11. Modification of radiation effects

    International Nuclear Information System (INIS)

    Lindenbaum, A.

    1975-01-01

    Results are reported from studies on the tissue distribution of 239 Pu and 241 Am in mice and beagle dogs and the effectiveness of various therapeutic treatments for decorporation. In dogs injected with monomeric Pu the value of a regimen of early and prolonged treatment with DTPA (diethylenetriaminepentaacetic acid) for minimizing the Pu burden in the soft tissues and skeleton was demonstrated. These results have immediate implication for DTPA treatment in man. New studies in mice verified the action of pyran copolymer antiviral agents in enhancing the effectiveness of DTPA for removal of polymeric Pu from the liver. Recent application of autoradiographic procedures for quantitatively comparing short- and long-term localization of monomeric and polymeric 239 Pu in dog liver showed that there is no net translocation of monomeric Pu within the liver between 6 and 90 days following injection. One of the molecular studies presently underway aims at synthesis of a variety of DTPA esters. The diethyl ester has already been prepared and tested for toxicity in mice. These compounds are designed to bring DTPA into contact with plutonium deposits unavailable to the action of ionic DTPA. (U.S.)

  12. Radiation effects on living systems

    International Nuclear Information System (INIS)

    Hawley, N.J.

    1984-04-01

    This bibliography includes papers and reports by Atomic Energy of Canada Limited scientists concerning radiation effects on living systems. It is divided into three sections: Radiobiology, Radiation Biochemistry and Radiation Chemistry. It is intended that the bibliography will be updated regularly

  13. Research on radiation effect and radiation protection at JAEA

    International Nuclear Information System (INIS)

    Saito, Kimiaki

    2007-01-01

    Researches on radiation effect and radiation protection at JAEA have been carried out in different sections. In recent years, the organizations were rearranged to attain better research circumstances, and new research programs started. At present, radiation effect studies focus on radiation effect mechanisms at atomic, molecular and cellular levels including simulation studies, and protection studies focus on dosimetry for conditions difficult to cover with currently used methods and data as well as the related basic studies. The outlines of the whole studies and also some descriptions on selected subjects will be given in this paper. (author)

  14. Radiation effects and radioprotectors

    Energy Technology Data Exchange (ETDEWEB)

    Purohit, R.K., E-mail: dr_rajendra_purohit@yahoo.co.in [Radiation Biology Laboratory, Department of Zoology, Govt. Dungar College, Bikaner (India); Bugalia, Saroj [Department of Zoology, S.K. Kalyan College, Sikar (India); Dakshene, Monika [Department of Chemistry, Govt. College, Kota (India)

    2012-07-01

    -protective compounds are highly toxic at their effective dose levels except MPG and hence attempts were made to find out a non-toxic agent which can minimize the harmful effects of radiations. Secondly, the uses of radio-protectors so far studied have been restricted by their availability and cost. Therefore, there is a need for compounds which are very effective in radio-protection and at the same time non-toxic, inexpensive and easily available. Various indigenous drugs of plant origin are being used in the Indian system of medicine for the treatment of ailments. The Aloe vera, Embijea officinalis, Ocimum snctum and Liv.52 etc. have been used effectively against radiation induced effects in the mammalian body. (author)

  15. Radiation effects and radioprotectors

    International Nuclear Information System (INIS)

    Purohit, R.K.; Bugalia, Saroj; Dakshene, Monika

    2012-01-01

    -protective compounds are highly toxic at their effective dose levels except MPG and hence attempts were made to find out a non-toxic agent which can minimize the harmful effects of radiations. Secondly, the uses of radio-protectors so far studied have been restricted by their availability and cost. Therefore, there is a need for compounds which are very effective in radio-protection and at the same time non-toxic, inexpensive and easily available. Various indigenous drugs of plant origin are being used in the Indian system of medicine for the treatment of ailments. The Aloe vera, Embijea officinalis, Ocimum snctum and Liv.52 etc. have been used effectively against radiation induced effects in the mammalian body. (author)

  16. Overview of radiation effects research in photonics

    Science.gov (United States)

    Webb, Robert C.; Cohn, Lewis M.; Taylor, Edward W.; Greenwell, Roger A.

    1995-05-01

    A brief overview of ongoing radiation effects research in photonics is presented focusing on integrated optic and acousto-optic components. A short summary of radiation-induced effects in electro-optic modulators, detector arrays, and other photonic technologies is presented along with extensive references. The coordinated radiation effects studies among researchers within the Tri-Service Organizations and international experimental teams are beginning to demonstrate consistent measurements of radiation-induced effects in photonic components and confirming earlier reported data. This paper will present an overview of these coordinated investigations and focus on key research being conducted with the AFMC Phillips Laboratory, Naval Research Laboratory, Defence Nuclear Agency, NATO Nuclear Effects Task Group, and the Tri-Service Photonics Coordinating Committee.

  17. Ionizing radiation effect on human reproduction

    International Nuclear Information System (INIS)

    Jirous, J.

    1987-01-01

    A review is presented of the existing knowledge on the adverse effects of ionizing radiation on human reproduction. Some interesting findings have been obtained by interapolating the results of studies in mouse embryos to humans, important knowledge has been obtained in studies involving the population of Hiroshima and Nagasaki. The review summarizes the knowledge in the following conclusions: (1) prior to the blastocyst stage, the mammalian embryo is insensitive to teratogenic and growth retarding radiation effects but is highly sensitive to the lethal radiation effect; (2) in the early organogenesis, the embryo is very sensitive to growth retarding, teratogenic and lethal radiation effects. It can, however, partly offset growth retardation in the post-natal period; (3) in the early fetal development stage, the fetus shows reduced sensitivity to teratogenic damage of many organs; sensitivity of the central nervous system and growth retardation remain which can only be compensated post-natally with difficulties; (4) in the late stage of pregnancy the fetus is not significantly deformed as a result of irradiation but permanent cellular depletion can result in various organs and tissues post-natally if radiation doses are high. (L.O.). 22 refs

  18. Radiation Effects in Nuclear Waste Materials

    International Nuclear Information System (INIS)

    Weber, William J.

    2005-01-01

    The objective of this project is to develop a fundamental understanding of radiation effects in glasses and ceramics, as well as the influence of solid-state radiation effects on aqueous dissolution kinetics, which may impact the performance of nuclear waste forms and stabilized nuclear materials. This work provides the underpinning science to develop improved glass and ceramic waste forms for the immobilization and disposition of high-level tank waste, excess plutonium, plutonium residues and scrap, other actinides, and other nuclear waste streams. Furthermore, this work is developing develop predictive models for the performance of nuclear waste forms and stabilized nuclear materials. Thus, the research performed under this project has significant implications for the immobilization of High-Level Waste (HLW) and Nuclear Materials, two mission areas within the Office of Environmental Management (EM). With regard to the HLW mission, this research will lead to improved understanding of radiation-induced degradation mechanisms and their effects on dissolution kinetics, as well as development of predictive models for waste form performance. In the Nuclear Materials mission, this research will lead to improvements in the understanding of radiation effects on the chemical and structural properties of materials for the stabilization and long-term storage of plutonium, highly-enriched uranium, and other actinides. The research uses plutonium incorporation, ion-beam irradiation, and electron-beam irradiation to simulate the effects of alpha decay and beta decay on relevant glasses and ceramics. The research under this project has the potential to result in improved glass and ceramic materials for the stabilization and immobilization of high-level tank waste, plutonium residues and scraps, surplus weapons plutonium, highly-enriched uranium, other actinides, and other radioactive materials

  19. Radiation Effects in Nuclear Waste Materials

    International Nuclear Information System (INIS)

    Weber, William J.; Wang, Lumin; Hess, Nancy J.; Icenhower, Jonathan P.; Thevuthasan, Suntharampillai

    2003-01-01

    The objective of this project is to develop a fundamental understanding of radiation effects in glasses and ceramics, as well as the influence of solid-state radiation effects on aqueous dissolution kinetics, which may impact the performance of nuclear waste forms and stabilized nuclear materials. This work provides the underpinning science to develop improved glass and ceramic waste forms for the immobilization and disposition of high-level tank waste, excess plutonium, plutonium residues and scrap, other actinides, and other nuclear waste streams. Furthermore, this work is developing develop predictive models for the performance of nuclear waste forms and stabilized nuclear materials. Thus, the research performed under this project has significant implications for the immobilization of High-Level Waste (HLW) and Nuclear Materials, two mission areas within the Office of Environmental Management (EM). With regard to the HLW mission, this research will lead to improved understanding of radiation-induced degradation mechanisms and their effects on dissolution kinetics, as well as development of predictive models for waste form performance. In the Nuclear Materials mission, this research will lead to improvements in the understanding of radiation effects on the chemical and structural properties of materials for the stabilization and long-term storage of plutonium, highly-enriched uranium, and other actinides. The research uses plutonium incorporation, ion-beam irradiation, and electron-beam irradiation to simulate the effects of alpha decay and beta decay on relevant glasses and ceramics. The research under this project has the potential to result in improved glass and ceramic materials for the stabilization and immobilization of high-level tank waste, plutonium residues and scraps, surplus weapons plutonium, highly-enriched uranium, other actinides, and other radioactive materials

  20. Radiation effects and radiation risks. 2. ed.

    International Nuclear Information System (INIS)

    Lengfelder, E.; Forst, D.; Feist, H.; Pratzel, H.G.

    1990-01-01

    The book presents the facts and the principles of assessment and evaluation of biological radiation effects in general and also with particular reference to the reactor accident of Chernobyl, reviewing the consequences and the environmental situation on the basis of current national and international literature, including research work by the authors. The material compiled in this book is intended especially for physicians, but will also prove useful for persons working in the public health services, in administration, or other services taking care of people. The authors tried to find an easily comprehensible way of presenting and explaining the very complex processes and mechanisms of biological radiation effects and carcinogenesis, displaying the physical primary processes and the mechanisms of the molecular radiation effects up to the effects of low-level radiation, and present results of comparative epidemiologic studies. This section has been given considerable space, in proportion to its significance. It also contains literature references for further reading, offering more insight and knowledge of aspects of special subject fields. The authors also present less known results and data and discuss them against the background of well-known research results and approaches. Apart from the purpose of presenting comprehensive information, the authors intend to give an impact for further thinking about the problems, and helpful tools for independent decisions and action on the basis of improved insight and assessment, and in this context particularly point to the problems induced by the Chernobyl reactor accident. (orig.) With 10 maps in appendix [de

  1. Measuring Science Curriculum Improvement Study Teachers' Attitudinal Changes Toward Science.

    Science.gov (United States)

    Hovey, Larry Michael

    Investigated were three questions related to the relationship between a science teacher's attitude regarding the use of a newer science program, in this instance the Science Curriculum Improvement Study (SCIS): (1) Could the Projective Tests of Attitudes, originally designed for fifth-grade students, be modified for use with adults? (2) Is there a…

  2. A functional genomics approach using radiation-induced changes in gene expression to study low dose radiation effects in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Fornace, Jr, A J

    2007-03-03

    Abstract for final report for project entitled A functional genomics approach using radiation-induced changes in gene expression to study low dose radiation effects in vitro and in vivo which has been supported by the DOE Low Dose Radiation Research Program for approximately 7 years. This project has encompassed two sequential awards, ER62683 and then ER63308, in the Gene Response Section in the Center for Cancer Research at the National Cancer Institute. The project was temporarily suspended during the relocation of the Principal Investigators laboratory to the Dept. of Genetics and Complex Diseases at Harvard School of Public Health at the end of 2004. Remaining support for the final year was transferred to this new site later in 2005 and was assigned the DOE Award Number ER64065. The major aims of this project have been 1) to characterize changes in gene expression in response to low-dose radiation responses; this includes responses in human cells lines, peripheral blood lymphocytes (PBL), and in vivo after human or murine exposures, as well as the effect of dose-rate on gene responses; 2) to characterize changes in gene expression that may be involved in bystander effects, such as may be mediated by cytokines and other intercellular signaling proteins; and 3) to characterize responses in transgenic mouse models with relevance to genomic stability. A variety of approaches have been used to study transcriptional events including microarray hybridization, quantitative single-probe hybridization which was developed in this laboratory, quantitative RT-PCR, and promoter microarray analysis using genomic regulatory motifs. Considering the frequent responsiveness of genes encoding cytokines and related signaling proteins that can affect cellular metabolism, initial efforts were initiated to study radiation responses at the metabolomic level and to correlate with radiation-responsive gene expression. Productivity includes twenty-four published and in press manuscripts

  3. Case studies in conservation science

    Science.gov (United States)

    Bisulca, Christina

    The research presented in this dissertation covers three separate topics of conservation as defined by the National Science Foundation: 1) Materials Stabilization, Strengthening, Monitoring, and Repair; 2. Understanding Material Degradation and Aging; and 3) Materials and Structural Characterization of Cultural Heritage Objects (the 'technical study'). The first topic is addressed through a study to assess the consolidant tetraethoxysilane for the stabilization of alum treated wood. Falling under materials degradation studies is a study published in American Museum Novitates to understand how environmental conditions affect the aging of fossil resins from five different deposits. Two separate studies are included in technical study of cultural heritage objects which comprises the third research area of materials characterization. The first is a survey of red dyes used in Chinese paintings from the Ming Dynasty to the Early Republic (1364-1911). The second is a study of the pigments, dyes and binders used in Hawaiian barkcloth (kapa) from the 19th century.

  4. Radiation Effects in Paediatric radiography

    International Nuclear Information System (INIS)

    Mutwasi, O.

    2006-01-01

    Diagnostic imaging has evolved from single technique to a field which we have a choice from many modalities. Some without radiation. Radiation producing modalities include plain films (low dose), Fluoroscopy (mid range dose), Computed tomography (high dose). Radiography dose can significantly be influenced in plain radiography by varying speed of screens, cassette construction and type of radiography. E.g. digital or computed. In computed or digital radiography we are no longer able to tell h igh dose b y the quality of images. The final image is by great extend a product of post processing algorithms. It's for this reasons that the basic understanding of the sensitivity and specifying of various types of examinations and of specifically radiation effects is mandatory for a paediatric imager

  5. Study of the radiation effect of "9"9Mo/"9"9"mTc generator on Bacillus subtilis and Bacillus pumilus species

    International Nuclear Information System (INIS)

    Fukumori, Neuza T.O.; Endo, Erica M.M.; Felgueiras, Carlos F.; Matsuda, Margareth M.N.; Osso Junior, João A.

    2016-01-01

    In this work, molybdenum-99 loaded columns were challenged with Bacillus subtilis vegetative cells and Bacillus pumilus spores inside and outside the alumina column, and microbial recovery and radiation effect were assessed. Alumina was a barrier for the passage of microorganisms regardless the species, whilst spores were more retained than vegetative cells with a lower microbial recovery, without significant differences between 9.25 and 74 GBq generators. Bacillus pumilus biological indicator showed lower recoveries, suggesting a radiation inactivating effect on microorganisms. - Highlights: • Microorganisms in radionuclide generator may impair the quality of the product. • Killing of Bacillus pumilus was not complete even after 20 days of exposition. • Alumina column was a physical barrier for the microbial recovery. • An alternative biological indicator based on B. pumilus spores is proposed.

  6. Radiation effects in charge coupled devices

    International Nuclear Information System (INIS)

    Williams, R.A.; Nelson, R.D.

    1975-01-01

    Charge coupled devices (CCD s) exhibit a number of advantages (low cost, low power, high bit density) in their several applications (serial memories, imagers, digital filters); however, fairly elementary theoretical considerations indicate that they will be very vulnerable to permanent radiation damage, by both neutrons and ionizing radiation, and to transient upset by pulsed ionizing radiation. Although studies of permanent ionizing-radiation damage in CCD's have been reported, little information has been published concerning their overall nuclear radiation vulnerability. This paper presents a fairly comprehensive experimental study of radiation effects in a 256-cell surface-channel, CCD shift-register. A limited amount of similar work is also presented for a 128-cell surface-channel device and a 130 cell peristaltic CCD shift register. The radiation effects phenomena discussed herein, include transient-ionizing-radiation responses, permanent ionizing- radiation damage to transfer efficiency, charge-carrying capacity and input transfer gate bias, and neutron damage to storage time--determined from dark current and charge-up time measurements

  7. Radiation effects on materials in high-radiation environments

    International Nuclear Information System (INIS)

    Weber, W.J.; Mansur, L.K.; Clinard, F.W. Jr.; Parkin, D.M.

    1991-01-01

    A workshop on Radiation Effects on Materials in High-Radiation Environments was held in Salt Lake City, Utah (USA) from August 13 to 15, 1990 under the auspices of the Division of Materials Sciences, Office of Basic Energy Sciences, US Department of Energy. The workshop focused on ceramics, alloys, and intermetallics and covered research needs and capabilities, recent experimental data, theory, and computer simulations. It was concluded that there is clearly a continuing scientific and technological need for fundamental knowledge on the underlying causes of radiation-induced property changes in materials. Furthermore, the success of many current and emerging nuclear-related technologies critically depend on renewed support for basic radiation-effects research, irradiation facilities, and training of scientists. The highlights of the workshop are reviewed and specific recommendations are made regarding research needs. (orig.)

  8. Politicizing science: conceptions of politics in science and technology studies.

    Science.gov (United States)

    Brown, Mark B

    2015-02-01

    This essay examines five ideal-typical conceptions of politics in science and technology studies. Rather than evaluating these conceptions with reference to a single standard, the essay shows how different conceptions of politics serve distinct purposes: normative critique, two approaches to empirical description, and two views of democracy. I discuss each conception of politics with respect to how well it fulfills its apparent primary purpose, as well as its implications for the purpose of studying a key issue in contemporary democratic societies: the politicization of science. In this respect, the essay goes beyond classifying different conceptions of politics and also recommends the fifth conception as especially conducive to understanding and shaping the processes whereby science becomes a site or object of political activity. The essay also employs several analytical distinctions to help clarify the differences among conceptions of politics: between science as 'political' (adjective) and science as a site of 'politics' (noun), between spatial-conceptions and activity-conceptions of politics, between latent conflicts and actual conflicts, and between politics and power. The essay also makes the methodological argument that the politics of science and technology is best studied with concepts and methods that facilitate dialogue between actors and analysts. The main goal, however, is not to defend a particular view of politics, but to promote conversation on the conceptions of politics that animate research in social studies of science and technology.

  9. Science Anxiety, Science Attitudes, and Constructivism: A Binational Study

    Science.gov (United States)

    Bryant, Fred B.; Kastrup, Helge; Udo, Maria; Hislop, Nelda; Shefner, Rachel; Mallow, Jeffry

    2013-08-01

    Students' attitudes and anxieties about science were measured by responses to two self-report questionnaires. The cohorts were Danish and American students at the upper secondary- and university-levels. Relationships between and among science attitudes, science anxiety, gender, and nationality were examined. Particular attention was paid to constructivist attitudes about science. These fell into at least three broad conceptual categories: Negativity of Science Toward the Individual, Subjective Construction of Knowledge, and Inherent Bias Against Women. Multigroup confirmatory factor analyses revealed that these dimensions of constructivist attitudes were equally applicable and had the same meaning in both cultures. Gender differences in mean levels of constructivist attitudes were found; these varied across the two cultures. Constructivist beliefs were associated with science anxiety, but in different ways for females and males, and for Danes and Americans. In agreement with earlier studies, females in both the US and Danish cohorts were significantly more science anxious than males, and the gender differences for the Americans were larger than those for the Danes. Findings are discussed in terms of their implications for reducing science anxiety by changing constructivist beliefs.

  10. Cultural studies of science education

    Science.gov (United States)

    Higgins, Joanna; McDonald, Geraldine

    2008-07-01

    In response to Stetsenko's [2008, Cultural Studies of Science Education, 3] call for a more unified approach in sociocultural perspectives, this paper traces the origins of the use of sociocultural ideas in New Zealand from the 1970s to the present. Of those New Zealanders working from a sociocultural perspective who responded to our query most had encountered these ideas while overseas. More recently activity theory has been of interest and used in reports of work in early childhood, workplace change in the apple industry, and in-service teacher education. In all these projects the use of activity theory has been useful for understanding how the elements of a system can transform the activity. We end by agreeing with Stetsenko that there needs to be a more concerted approach by those working from a sociocultural perspective to recognise the contribution of others in the field.

  11. The Brookhaven Radiation Effects Facility

    Energy Technology Data Exchange (ETDEWEB)

    Grand, P.; Snead, C.L.; Ward, T.

    1988-01-01

    The Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO) through the Defense Nuclear Agency (DNA) and the Air Force Weapons Laboratory (AFWL), has been constructed at Brookhaven National Laboratory (BNL). Operation started in October 1986. The facility is capable of delivering pulsed H{sup -}, H{sup o}, and H{sup +} beams of 100 to 200 MeV energy up to 30 mA peak current. Pulses can be adjusted from 5 {mu}s to 500 {mu}s length at a repetition rate of 5 pps. The beam spot on target is adjustable from 3 to 100 cm diameter (2 {sigma}) resulting in a maximum dose of about 10 MRads (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality (LTH-4) program. The program has addressed ionization effects in electronics, both dose rate and total dose dependence, radiation-sensitive components, and dE/dx effects in energetic materials including propellants and high explosives (HE). This paper describes the facility, its capabilities and potential, and the experiments that have been carried out to date or are being planned. 2 refs., 10 figs.

  12. The Brookhaven Radiation Effects Facility

    International Nuclear Information System (INIS)

    Grand, P.; Snead, C.L.; Ward, T.

    1988-01-01

    The Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO) through the Defense Nuclear Agency (DNA) and the Air Force Weapons Laboratory (AFWL), has been constructed at Brookhaven National Laboratory (BNL). Operation started in October 1986. The facility is capable of delivering pulsed H - , H/sup o/, and H + beams of 100 to 200 MeV energy up to 30 mA peak current. Pulses can be adjusted from 5 μs to 500 μs length at a repetition rate of 5 pps. The beam spot on target is adjustable from 3 to 100 cm diameter (2 σ) resulting in a maximum dose of about 10 MRads (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality (LTH-4) program. The program has addressed ionization effects in electronics, both dose rate and total dose dependence, radiation-sensitive components, and dE/dx effects in energetic materials including propellants and high explosives (HE). This paper describes the facility, its capabilities and potential, and the experiments that have been carried out to date or are being planned. 2 refs., 10 figs

  13. Radiation Effects in Nuclear Ceramics

    Directory of Open Access Journals (Sweden)

    L. Thomé

    2012-01-01

    Full Text Available Due to outstanding physicochemical properties, ceramics are key engineering materials in many industrial domains. The evaluation of the damage created in ceramics employed in radiative media is a challenging problem for electronic, space, and nuclear industries. In this latter field, ceramics can be used as immobilization forms for radioactive wastes, inert fuel matrices for actinide transmutation, cladding materials for gas-cooled fission reactors, and structural components for fusion reactors. Information on the radiation stability of nuclear materials may be obtained by simulating the different types of interactions involved during the slowing down of energetic particles with ion beams delivered by various types of accelerators. This paper presents a review of the radiation effects occurring in nuclear ceramics, with an emphasis on recent results concerning the damage accumulation processes. Energetic ions in the KeV-GeV range are used to explore the nuclear collision (at low energy and electronic excitation (at high energy regimes. The recovery by electronic excitation of the damage created by ballistic collisions (SHIBIEC process is also addressed.

  14. Radiation effects on relativistic electrons in strong external fields

    International Nuclear Information System (INIS)

    Iqbal, Khalid

    2013-01-01

    The effects of radiation of high energy electron beams are a major issue in almost all types of charged particle accelerators. The objective of this thesis is both the analytical and numerical study of radiation effects. Due to its many applications the study of the self force has become a very active and productive field of research. The main part of this thesis is devoted to the study of radiation effects in laser-based plasma accelerators. Analytical models predict the existence of radiation effects. The investigation of radiation reaction show that in laser-based plasma accelerators, the self force effects lower the energy gain and emittance for moderate energies electron beams and increase the relative energy spread. However, for relatively high energy electron beams, the self radiation and retardation (radiation effects of one electron on the other electron of the system) effects increase the transverse emittance of the beam. The energy gain decreases to even lower value and relative energy spread increases to even higher value due to high radiation losses. The second part of this thesis investigates with radiation reaction in focused laser beams. Radiation effects are very weak even for high energy electrons. The radiation-free acceleration and the simple practical setup make direct acceleration in a focused laser beam very attractive. The results presented in this thesis can be helpful for the optimization of future electron acceleration experiments, in particular in the case of laser-plasma accelerators.

  15. Science Studies from Archived Observations

    Science.gov (United States)

    Armstrong, T. P.; Manweiler, J. W.; Patterson, J. D.

    2008-12-01

    Goals for spaceflight investigations include the discovery and characterization of physical features of the in- situ and remote environment. Abundant successes of flight investigations are easily documented. Prudent scientific practice dictates that to the maximum extent possible, observations should be well-characterized, reliably catalogued, and knowledgeably interpreted. This is especially true of data sets used in the publication of results in the reviewed literature. Typical scientific standards include making primary data numbers available to other investigators for replicated study. While NASA's contracts with investigators have required that data be submitted to agency official archives, the details, completeness (especially of ancillary and metadata) and forms differ from investigation to investigation and project to project. After several generations of improvements and refinements, modern computing and communications technology makes it possible to link multiple data sets at multiple locations through a unified data model. Virtual Observatories provide the overall organizational structures and SPASE-compliant XML defines the data granules that can be located. Proofs of the feasibility and value of this latest approach remain to be seen, but its ultimate goal of improving archival research using flight-derived data sets appears to depend on user acceptance and efficient use of the VxO resources. Criteria based on the authors experience in science derived from archival sources follow: 1. Interfaces and tools must be easy to learn, easy to use, and reliable. 2. Data numbers must be promptly downloadable in plain text. 3. Data must be available in or readily converted to physical units using calibrations and algorithms easily traceable as part of the search. Knowledge about (or heritage of) specific data items present in the science literature must be associated with the search for that item. 4. Data items must be trustworthy, having quoted uncertainties and

  16. Overview of radiation effects on emerging non-volatile memory technologies

    Directory of Open Access Journals (Sweden)

    Fetahović Irfan S.

    2017-01-01

    Full Text Available In this paper we give an overview of radiation effects in emergent, non-volatile memory technologies. Investigations into radiation hardness of resistive random access memory, ferroelectric random access memory, magneto-resistive random access memory, and phase change memory are presented in cases where these memory devices were subjected to different types of radiation. The obtained results proved high radiation tolerance of studied devices making them good candidates for application in radiation-intensive environments. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 171007

  17. Errors and Uncertainties in Dose Reconstruction for Radiation Effects Research

    Energy Technology Data Exchange (ETDEWEB)

    Strom, Daniel J.

    2008-04-14

    Dose reconstruction for studies of the health effects of ionizing radiation have been carried out for many decades. Major studies have included Japanese bomb survivors, atomic veterans, downwinders of the Nevada Test Site and Hanford, underground uranium miners, and populations of nuclear workers. For such studies to be credible, significant effort must be put into applying the best science to reconstructing unbiased absorbed doses to tissues and organs as a function of time. In many cases, more and more sophisticated dose reconstruction methods have been developed as studies progressed. For the example of the Japanese bomb survivors, the dose surrogate “distance from the hypocenter” was replaced by slant range, and then by TD65 doses, DS86 doses, and more recently DS02 doses. Over the years, it has become increasingly clear that an equal level of effort must be expended on the quantitative assessment of uncertainty in such doses, and to reducing and managing uncertainty. In this context, this paper reviews difficulties in terminology, explores the nature of Berkson and classical uncertainties in dose reconstruction through examples, and proposes a path forward for Joint Coordinating Committee for Radiation Effects Research (JCCRER) Project 2.4 that requires a reasonably small level of effort for DOSES-2008.

  18. The radiation effects on lipid bilayers

    International Nuclear Information System (INIS)

    Ikigai, Hajime; Matsuura, Tomio; Narita, Noboru; Ozawa, Atsushi.

    1980-01-01

    The Radiation effects on lipid bilayers are studied by the electron spin resonance. Egg lecithin liposomes and human erythrocytes are labeled with spin probes (5 SAL, 12 SAL). Effects of membrane fluidity by X-Ray (or ultraviolet) irradiation are measured by change of the order parameter S. The results obtained are as follows: 1) A similar tendency is observed on the order parameter S between X-Ray irradiated egg lecithin liposomes and human erythrocytes. 2) The rapid changes of the membrane fluidity are observed below 1 krad. The fluctuation of membrane fluidity decreases above 1 krad, consequently the membrane has a tendency changing to a rigid state at low dose area. 3) It is suggested that the more effective radicals are hydroxyl radicals and superoxide radicals. 4) The effects of ultraviolet irradiation with hydrogen peroxide show that hydroxyl radicals lead to changes of membrane fluidity. (author)

  19. RADIATION EFFECTS IN NUCLEAR WASTE MATERIALS

    International Nuclear Information System (INIS)

    Weber, William J.

    2000-01-01

    The objective of this research was to develop fundamental understanding and predictive models of radiation effects in glasses and ceramics at the atomic, microscopic, and macroscopic levels, as well as an understanding of the effects of these radiation-induced solid-state changes on dissolution kinetics (i.e., radionuclide release). The research performed during the duration of this project has addressed many of the scientific issues identified in the reports of two DOE panels [1,2], particularly those related to radiation effects on the structure of glasses and ceramics. The research approach taken by this project integrated experimental studies and computer simulations to develop comprehensive fundamental understanding and capabilities for predictive modeling of radiation effects and dissolution kinetics in both glasses and ceramics designed for the stabilization and immobilization of high-level tank waste (HLW), plutonium residues and scraps, surplus weapons plutonium, other actinides, and other highly radioactive waste streams. Such fundamental understanding is necessary in the development of predictive models because all experimental irradiation studies on nuclear waste materials are ''accelerated tests'' that add a great deal of uncertainty to predicted behavior because the damage rates are orders of magnitude higher than the actual damage rates expected in nuclear waste materials. Degradation and dissolution processes will change with damage rate and temperature. Only a fundamental understanding of the kinetics of all the physical and chemical processes induced or affected by radiation will lead to truly predictive models of long-term behavior and performance for nuclear waste materials. Predictive models of performance of nuclear waste materials must be scientifically based and address both radiation effects on structure (i.e., solid-state effects) and the effects of these solid-state structural changes on dissolution kinetics. The ultimate goal of this

  20. Errors, uncertainties and other problems associated with the interpretation of transgenerational epidemiological studies with special reference to postulated ionising radiation effects

    International Nuclear Information System (INIS)

    Slovak, A.J.M.

    2000-01-01

    The transgenerational effects debate of recent years can, in the light of current knowledge, be seen as a working example of the operation of a powerful range of errors, biases and confounders. These have often helped to obfuscate the issues addressed to the disbenefit of interested parties such as vicinity populations and workforces. The possibility of transgenerational effects has been entertained as a theoretical constant throughout the history of radiation science being given particular direction and focus by the work of Mueller in the 1920's. The absence of such effect in bomb survivors was therefore somewhat surprising to researchers even though this relative radio resistance was confirmed by later animal studies, such as by Russell and Selby. For emotive and situational reasons the renewed transgenerational debate of the last couple of decades has focused largely on childhood leukaemia, a very late, even remote-manifesting putative, transgenerational effect. This effect has now been demonstrated to be mainly due to confounding, most likely by population mixing, even in the sentinel study population of Seascale, near Sellafield. Little attention had been paid to the nature of the biological plausibility of putative transgenerational effects of ionizing radiation in terms of likelihood and closeness of fit. Thus there is a likelihood gradient of expected magnitude of effect which may be predicted to run from early to late manifesting defects. This would be expected to be high for pre-implantation loss and low for stillbirths or childhood cancer. Cited biological concordance also seldom takes regard of dose and dose rate. This is a particular problem because many epidemiological studies use more or less crude surrogate of dose such as monitored/never monitored or mechanical proportionalisation of annual dose summaries to shorter critical periods (such as spermatogenesis). In questionnaire studies, which are often regarded as inescapable in reproductive

  1. Notes on radiation effects on materials

    International Nuclear Information System (INIS)

    Anno, J.N.

    1984-01-01

    The effects of radiation from nuclear reactions on various classes of materials are examined in an introductory textbook for students of nuclear engineering. Topics discussed include the units and general scale of radiation damage, fundamental interactions of neutrons and gamma rays with materials, transient radiation effects on electrical components, radiation effects on organic materials and on steels, nuclear fission effects, surface effects of nuclear radiations, radiation effects on biological material, and neutron and gamma-ray dosimetry. Graphs, diagrams, tables of numerical data, and problems for each chapter are provided. 122 references

  2. A study of science leadership and science standards in exemplary standards-based science programs

    Science.gov (United States)

    Carpenter, Wendy Renae

    The purpose for conducting this qualitative study was to explore best practices of exemplary standards-based science programs and instructional leadership practices in a charter high school and in a traditional high school. The focus of this study included how twelve participants aligned practices to National Science Education Standards to describe their science programs and science instructional practices. This study used a multi-site case study qualitative design. Data were obtained through a review of literature, interviews, observations, review of educational documents, and researcher's notes collected in a field log. The methodology used was a multi-site case study because of the potential, through cross analysis, for providing greater explanation of the findings in the study (Merriam, 1988). This study discovered six characteristics about the two high school's science programs that enhance the literature found in the National Science Education Standards; (a) Culture of expectations for learning-In exemplary science programs teachers are familiar with a wide range of curricula. They have the ability to examine critically and select activities to use with their students to promote the understanding of science; (b) Culture of varied experiences-In exemplary science programs students are provided different paths to learning, which help students, take in information and make sense of concepts and skills that are set forth by the standards; (c) Culture of continuous feedback-In exemplary science programs teachers and students work together to engage students in ongoing assessments of their work and that of others as prescribed in the standards; (d) Culture of Observations-In exemplary science programs students, teachers, and principals reflect on classroom instructional practices; teachers receive ongoing evaluations about their teaching and apply feedback towards improving practices as outlined in the standards; (e) Culture of continuous learning-In exemplary

  3. Internal friction, microstructure, and radiation effects

    International Nuclear Information System (INIS)

    Wechsler, M.S.; Sommer, W.F.; Davidson, D.R.

    1984-01-01

    A brief review is given of internal friction relaxation peaks and background internal friction. The microstructural origin of the internal friction is discussed. Particular emphasis is placed on radiation effects

  4. Sterilizing radiation effects on selected polymers

    International Nuclear Information System (INIS)

    Skiens, W.E.

    1979-03-01

    The mechanism of radiation effects and their industrial applications are discussed for the following classes of polymers: thermoplastics, thermosets, elastomers, films and fibers, and adhesives/coatings/potting compounds. 35 references, 3 tables

  5. Radiation Effects in M and NEMS

    Science.gov (United States)

    2016-03-31

    electrical basis of operation of M&NEM structures? In particular, cumulative damage by non - ionizing energy loss can, in principle, alter the... Radiation Effects in M&NEMS Michael Alles, Kirill Bolotin, Alex Zettl, Brian Homeijer, Jim Davidson, Ronald Schrimpf, Robert Reed, Dan Fleetwood...understanding radiation effects on the relevant properties of the constituent materials and structures, particularly advanced 2D materials, and the

  6. Radiation effects on microelectronics in space

    International Nuclear Information System (INIS)

    Srour, J.R.; McGarrity, J.M.

    1988-01-01

    The basic mechanisms of space radiation effects on microelectronics are reviewed in this paper. Topics discussed include the effects of displacement damage and ionizing radiation on devices and circuits, single event phenomena, dose enhancement, radiation effects on optoelectronic devices and passive components, hardening approaches, and simulation of the space radiation environment. A summary is presented of damage mechanisms that can cause temporary or permanent failure of devices and circuits operating in space

  7. Cohort studies in health sciences librarianship.

    Science.gov (United States)

    Eldredge, Jonathan

    2002-10-01

    What are the key characteristics of the cohort study design and its varied applications, and how can this research design be utilized in health sciences librarianship? The health, social, behavioral, biological, library, earth, and management sciences literatures were used as sources. All fields except for health sciences librarianship were scanned topically for either well-known or diverse applications of the cohort design. The health sciences library literature available to the author principally for the years 1990 to 2000, supplemented by papers or posters presented at annual meetings of the Medical Library Association. A narrative review for the health, social, behavioral, biological, earth, and management sciences literatures and a systematic review for health sciences librarianship literature for the years 1990 to 2000, with three exceptions, were conducted. The author conducted principally a manual search of the health sciences librarianship literature for the years 1990 to 2000 as part of this systematic review. The cohort design has been applied to answer a wide array of theoretical or practical research questions in the health, social, behavioral, biological, and management sciences. Health sciences librarianship also offers several major applications of the cohort design. The cohort design has great potential for answering research questions in the field of health sciences librarianship, particularly evidence-based librarianship (EBL), although that potential has not been fully explored.

  8. Different Traditions in the Study of Disciplinarity in Science--Science and Technology Studies, Library and Information Science and Scientometrics

    Science.gov (United States)

    Milojevic, Staša

    2013-01-01

    Introduction: Disciplinarity and other forms of differentiation in science have long been studied in the fields of science and technology studies, information science and scientometrics. However, it is not obvious whether these fields are building on each other's findings. Methods: An analysis is made of 609 articles on disciplinarity…

  9. Dependence of radiation effects in the progeny of the fist and second generation on stages of the development of germ cell of both parents at the time of irradiation: Experimental studies

    International Nuclear Information System (INIS)

    Nefyodov, I.; Nefyodova, I.; Palyga, G.

    1997-01-01

    Studies of 35199 offspring of Wistar rats showed that after irradiation of both parents (P) with doses of 0.25-4 Gy the manifestation of radiation effects in the descendants of the first (F1) and second (F2) generations in ontogenesis depended upon radiation dose and the stage of development of P germ cells at the moment of radiation exposure. After irradiation of the matured oocytes, spermatidis and spermatozoids the consequences for FI are mainly determined by a female or their aggravation takes place. After irradiation of the maturing oocytes, spermatocytes and spermatogonia the effects for F1 are mainly determined by the male. The death of F1 occurs chiefly in embryogenesis and F2 in early postnatal ontogenesis. It is more marked by the father's line (the descendants of F1 males and intact females) than by mother's line (the descendants of F1 females and intact males). (author)

  10. Radiation effects in bulk and nanostructured silicon

    Energy Technology Data Exchange (ETDEWEB)

    Holmstrom, E.

    2012-07-01

    Understanding radiation effects in silicon (Si) is of great technological importance. The material, being the basis of modern semiconductor electronics and photonics, is subjected to radiation already at the processing stage, and in many applications throughout the lifetime of the manufactured component. Despite decades of research, many fundamental questions on the subject are still not satisfactorily answered, and new ones arise constantly as device fabrication shifts towards the nanoscale. In this study, methods of computational physics are harnessed to tackle basic questions on the radiation response of bulk and nanostructured Si systems, as well as to explain atomic-scale phenomena underlying existing experimental results. Empirical potentials and quantum mechanical models are coupled with molecular dynamics simulations to model the response of Si to irradiation and to characterize the created crystal damage. The threshold displacement energy, i.e., the smallest recoil energy required to create a lattice defect, is determined in Si bulk and nanowires, in the latter system also as a function of mechanical strain. It is found that commonly used values for this quantity are drastically underestimated. Strain on the nanowire causes the threshold energy to drop, with an effect on defect production that is significantly higher than in an another nanostructure with similar dimensions, the carbon nanotube. Simulating ion irradiation of Si nanowires reveals that the large surface area to volume ratio of the nanostructure causes up to a three-fold enhancement in defect production as compared to bulk Si. Amorphous defect clusters created by energetic neutron bombardment are predicted, on the basis of their electronic structure and abundance, to cause a deleterious phenomenon called type inversion in Si strip detectors in high-energy physics experiments. The thinning of Si lamellae using a focused ion beam is studied in conjunction with experiment to unravel the cause for

  11. The handbook of science and technology studies

    CERN Document Server

    Fouché, Rayvon; Miller, Clark A; Smith-Doerr, Laurel

    2017-01-01

    Science and Technology Studies (STS) is a flourishing interdisciplinary field that examines the transformative power of science and technology to arrange and rearrange contemporary societies. The Handbook of Science and Technology Studies provides a comprehensive and authoritative overview of the field, reviewing current research and major theoretical and methodological approaches in a way that is accessible to both new and established scholars from a range of disciplines. This new edition, sponsored by the Society for Social Studies of Science, is the fourth in a series of volumes that have defined the field of STS. It features 36 chapters, each written for the fourth edition, that capture the state of the art in a rich and rapidly growing field. One especially notable development is the increasing integration of feminist, gender, and postcolonial studies into the body of STS knowledge. The book covers methods and participatory practices in STS research; mechanisms by which knowledge, people, and societies ...

  12. Radiation effects on ion exchange materials

    International Nuclear Information System (INIS)

    Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

    1977-11-01

    An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references

  13. Neurophysiological appropriateness of ionizing radiation effects

    International Nuclear Information System (INIS)

    Nyagu, A.I.; Loganovsky, K.N.

    1997-01-01

    The goal of this study was to compare bioelectrical activity of the brain in remote period of acute radiation sickness (ARS), chronic and prenatal irradiation as a result of the Chernobyl disaster. Registration of computerized 19-channel EEG, visual and somato-sensory evoked potentials have been carried out for 70 patients who had a verified ARS, 100 Chernobyl disaster survivors, who have been working in the Chernobyl exclusion zone since 1986-87 during 5 and more years, 50 prenatally irradiated children, and relevant controls. The relative risks of neurophysiological abnormalities are 4.5 for the ARS-patients, 3.6 for the chronically irradiated persons and 3.7 for the prenatally irradiated children. The data obtained testify to possibility of radiation-induced neurophysiological abnormalities in examined Chernobyl accident survivors which seems to be non-stochastic effects of ionizing radiation. For all examined irradiated patients it was typically an increasing of δ- and β- powers of EEG, particularly, in the frontal lobe shifted to the left fronto-temporal region, but spectral power of both θ- and α-range was significantly depressed. Aforesaid signs together with data of evoked potentials reflect the structural and functional abnormalities of limbic system and the left hemisphere as the first revealed neurophysiological appropriateness of ionizing radiation effects. (author)

  14. Neurophysiological appropriateness of ionizing radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Nyagu, A I; Loganovsky, K N [Department of Neurology, Inst. of Clinical Radiology, Scientific Centre for Radiation Medicine of Academy of Medical Sciences of Ukraine, Kiev (Ukraine)

    1997-11-01

    The goal of this study was to compare bioelectrical activity of the brain in remote period of acute radiation sickness (ARS), chronic and prenatal irradiation as a result of the Chernobyl disaster. Registration of computerized 19-channel EEG, visual and somato-sensory evoked potentials have been carried out for 70 patients who had a verified ARS, 100 Chernobyl disaster survivors, who have been working in the Chernobyl exclusion zone since 1986-87 during 5 and more years, 50 prenatally irradiated children, and relevant controls. The relative risks of neurophysiological abnormalities are 4.5 for the ARS-patients, 3.6 for the chronically irradiated persons and 3.7 for the prenatally irradiated children. The data obtained testify to possibility of radiation-induced neurophysiological abnormalities in examined Chernobyl accident survivors which seems to be non-stochastic effects of ionizing radiation. For all examined irradiated patients it was typically an increasing of {delta}- and {beta}- powers of EEG, particularly, in the frontal lobe shifted to the left fronto-temporal region, but spectral power of both {theta}- and {alpha}-range was significantly depressed. Aforesaid signs together with data of evoked potentials reflect the structural and functional abnormalities of limbic system and the left hemisphere as the first revealed neurophysiological appropriateness of ionizing radiation effects. (author). 25 refs.

  15. Radiation effects on ion exchange materials

    Energy Technology Data Exchange (ETDEWEB)

    Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

    1977-11-01

    An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references.

  16. SU-E-T-13: A Feasibility Study of the Use of Hybrid Computational Phantoms for Improved Historical Dose Reconstruction in the Study of Late Radiation Effects for Hodgkin's Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Petroccia, H; O' Reilly, S; Bolch, W [J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL (United States); Mendenhall, N; Li, Z; Slopsema, R [Radiation Oncology, University of Florida Proton Therapy Institute, Jacksonville, FL (United States)

    2014-06-01

    Purpose: Radiation-induced cancer effects are well-documented following radiotherapy. Further investigation is needed to more accurately determine a dose-response relationship for late radiation effects. Recent dosimetry studies tend to use representative patients (Taylor 2009) or anthropomorphic phantoms (Wirth 2008) for estimating organ mean doses. In this study, we compare hybrid computational phantoms to patient-specific voxel phantoms to test the accuracy of University of Florida Hybrid Phantom Library (UFHP Library) for historical dose reconstructions. Methods: A cohort of 10 patients with CT images was used to reproduce the data that was collected historically for Hodgkin's lymphoma patients (i.e. caliper measurements and photographs). Four types of phantoms were generated to show a range of refinement from reference hybrid-computational phantom to patient-specific phantoms. Each patient is matched to a reference phantom from the UFHP Library based on height and weight. The reference phantom is refined in the anterior/posterior direction to create a ‘caliper-scaled phantom’. A photograph is simulated using a surface rendering from segmented CT images. Further refinement in the lateral direction is performed using ratios from a simulated-photograph to create a ‘photograph and caliper-scaled phantom’; breast size and position is visually adjusted. Patient-specific hybrid phantoms, with matched organ volumes, are generated and show the capabilities of the UF Hybrid Phantom Library. Reference, caliper-scaled, photograph and caliper-scaled, and patient-specific hybrid phantoms are compared with patient-specific voxel phantoms to determine the accuracy of the study. Results: Progression from reference phantom to patient specific hybrid shows good agreement with the patient specific voxel phantoms. Each stage of refinement shows an overall trend of improvement in dose accuracy within the study, which suggests that computational phantoms can show

  17. Radiation effects on biodegradable polyesters

    International Nuclear Information System (INIS)

    Hiroshi Mitomo; Darmawan Darwis; Fumio Yoshii; Keizo Makuuchi

    1999-01-01

    Poly(3-hydroxybutyrate) [P(3HB)] and its copolymer poly(3-hydroxybutyrate-co-3hydroxyvalerate) [P(3HB-co-3HV)] are microbial biodegradable polyesters produced by many types of bacteria. Poly(butylene succinate) (PBS) and poly(E-caprolactone) (PCL) are also biodegradable synthetic polyesters which have been commercialized. These thermoplastics are expected for wide usage in environmental protection and blocompatible applications. Radiation grafting of hydrophilic monomers onto many polymers, e.g., polyethylene and polypropylene has been studied mainly for biomedical applications. In the present study, radiation-induced graft polymerization of vinyl monomers onto PHB and P(3HB-co-3HV) was carried out and improvement of their properties was studied. Changes in the properties and biodegradability were compared with the degree of grafting. Radiation-induced crosslinking of PBS and PCL which relatively show thermal and irradiation stability was also carried out to improve their thermal stability or processability. Irradiation to PBS and PCL mainly resulted in crosslinking and characterization of these crosslinked polyesters was investigated

  18. Late radiation effects: status and needs of epidemiologic research

    International Nuclear Information System (INIS)

    Miller, R.W.

    1974-01-01

    Epidemiologic studies of late radiation effects in man are reviewed, based on exposure to the atomic bomb, radiotherapy, diagnostic radiations, and occupational or accidental exposures. Areas studied include: genetic effects, fertility, immunology, cancer, congenital malformations, growth and development, aging, cataracts, psychiatric effects, interactions with drugs or viruses, host susceptibility, and radiation factors. Cancer areas discussed include leukemia; thyroid, lung, breast, bone, and liver cancers; lymphoma; salivary gland tumors; brain tumors; nonleukemia cancers; intrauterine exposures; and preconception irradiation and childhood cancers. (U.S.)

  19. Radiation effects in C cells

    International Nuclear Information System (INIS)

    Alcaraz Banos, M.; Garcia Ayala, A.; Meseguer Penalver, J.; Genoves Garcia, J.L.

    1994-01-01

    The para follicular cell (C cell) ultrastructure of euthyroid, propyl thiouracil-treated (PTU) and protyrreline-treated (TRH) irradiated rabbit thyroid gland was studied. The ultrastructural features of C cells in the non-irradiated thyroid glands were similar to those described in other mammals. We have not observed the disappearance of the C cells in irradiated thyroid glands. Clusters of C cells were occasionally observed in the irradiated glands. The irradiated C cells showed intranuclear, filamentous bundles and a dense body together with a well-developed endoplasmic reticulum and numerous secretory vesicles. C cells follicles could be observed in irradiated and TRH-treated animals. (Author)

  20. Radiation effects on cell membranes

    International Nuclear Information System (INIS)

    Koeteles, G.J.

    1982-01-01

    The recent developments in the field of membrane biology of eukaryotic cells result in revival of relevant radiobiological studies. The spatial relations and chemical nature of membrane components provide rather sensitive targets. Experimental data are presented concerning the effects of relatively low doses of X-irradiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus - of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the multifold roles of radiationinduced membrane phenomena on the development and regeneration of radiation injuries. (orig.)

  1. Radiation effects on cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Koeteles, G.J.

    1982-11-01

    The recent developments in the field of membrane biology of eukaryotic cells result in revival of relevant radiobiological studies. The spatial relations and chemical nature of membrane components provide rather sensitive targets. Experimental data are presented concerning the effects of relatively low doses of X-irradiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus - of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the multifold roles of radiationinduced membrane phenomena on the development and regeneration of radiation injuries.

  2. Biological radiation effects and radioprotection standards

    International Nuclear Information System (INIS)

    Clerc, H.

    1991-03-01

    In this report, after recalling the mode of action of ionizing radiations, the notions of dose, dose equivalents and the values of natural irradiation, the author describes the biological radiation effects. Then he presents the ICRP recommendations and their applications to the french radioprotection system

  3. Radiation effects on Fischer-Tropsch syntheses

    International Nuclear Information System (INIS)

    Hatada, M.; Matsuda, K.

    1977-01-01

    Radiation effects on Fischer-Tropsch synthesis has been examined using high dose rate electron beams and Fe-Cu-diatomaceous earth catalyst. Yields of saturated hydrocarbons were found to increase by irradiation, but the yields of these compounds were decreased by raising reaction temperature without irradiation, suggesting the presence of radiation chemical process in catalytic reactions. (author)

  4. Study of radiative effects in 1.8 GeV/n 40Ar incident on Pb (Bevalac Experiment E486H)

    International Nuclear Information System (INIS)

    Hallman, T.; McIntyre, E.; Madansky, L.; Carroll, J.; Mulera, T.; Sagle, A.; Koontz, R.; Roche, G.; Schroeder, L.

    1981-01-01

    The experimental setup, instrumentation, and results of Experiment 486H at Bevalac to test the feasibility of studying two photon inclusive and inclusive lepton pair production in the presence of a high multiplicity of background secondaries are described. Some preliminary observations are discussed

  5. Morpho-functional study of ionizing radiation effects on the rabbits` femoral vein; Avaliacao morfofuncional do efeito da radiacao ionizante sobre a veia femoral. Estudo experimental em coelhos

    Energy Technology Data Exchange (ETDEWEB)

    Sakiyama, Mauro Yoshimitsu

    1996-12-31

    In this study we evaluate the effects of the ionizing radiation on the rabbits femoral vein. The samples of femoral vein were obtained from 56 New Zealand rabbits, male with ageing from 90 to 120 days, that were divided into 4 groups of 14 animals: one control group non-irradiated and three animal groups sacrificed 2 days, 14 days and 90 days after irradiation. In the three irradiated rabbits groups, each animal received the total dose 4000 cGy (rads) divided in 10 sessions of 400 cGy, a dose equivalent that utilized on clinical therapeutic. A morpho functional study of vein samples was carried out with: light microscopy: stained by hematoxin - eosin, Masson`s tricromic, and Verhoeff. Immunohistochemical: reactions of immunoperoxidase with monoclonal mouse anti-human endothelial cell factor CD-31 and anti-human Von Willebrand factor (factor VIII), to study the vein endothelium. Histomorphometry of elastic fiber system stained by Weigert`s resorcin-fuchsin with and without prior oxidation with oxone; for the study of mature, elaunin or pre-mature and oxytalan or young elastic fibers. Electronic microscopy: transmission and scanning. With the methodology utilized we observe changes in the femoral vein of the animals submitted to irradiation in relation to the control group, thus described: there is formation of vacuoles between the endothelium and the basal membrane, called sub endothelial vacuoles, in focal areas. The factor VIII and CD-31 endothelial antigens are preserved with no changes in their functions. Focal alterations are present in the endothelial surface with disorder in the setting and orientation of the endothelial cells. there is degeneration of the elastic fibers with significant decrease in their quantity in the stage, 2 days and 14 days after irradiation. There is increase in the quantity of elastic fibers in the late stage, 90 days after irradiation, tending to normality. In this present study, the changes described are not accompanied by venous

  6. Morpho-functional study of ionizing radiation effects on the rabbits` femoral vein; Avaliacao morfofuncional do efeito da radiacao ionizante sobre a veia femoral. Estudo experimental em coelhos

    Energy Technology Data Exchange (ETDEWEB)

    Sakiyama, Mauro Yoshimitsu

    1995-12-31

    In this study we evaluate the effects of the ionizing radiation on the rabbits femoral vein. The samples of femoral vein were obtained from 56 New Zealand rabbits, male with ageing from 90 to 120 days, that were divided into 4 groups of 14 animals: one control group non-irradiated and three animal groups sacrificed 2 days, 14 days and 90 days after irradiation. In the three irradiated rabbits groups, each animal received the total dose 4000 cGy (rads) divided in 10 sessions of 400 cGy, a dose equivalent that utilized on clinical therapeutic. A morpho functional study of vein samples was carried out with: light microscopy: stained by hematoxin - eosin, Masson`s tricromic, and Verhoeff. Immunohistochemical: reactions of immunoperoxidase with monoclonal mouse anti-human endothelial cell factor CD-31 and anti-human Von Willebrand factor (factor VIII), to study the vein endothelium. Histomorphometry of elastic fiber system stained by Weigert`s resorcin-fuchsin with and without prior oxidation with oxone; for the study of mature, elaunin or pre-mature and oxytalan or young elastic fibers. Electronic microscopy: transmission and scanning. With the methodology utilized we observe changes in the femoral vein of the animals submitted to irradiation in relation to the control group, thus described: there is formation of vacuoles between the endothelium and the basal membrane, called sub endothelial vacuoles, in focal areas. The factor VIII and CD-31 endothelial antigens are preserved with no changes in their functions. Focal alterations are present in the endothelial surface with disorder in the setting and orientation of the endothelial cells. there is degeneration of the elastic fibers with significant decrease in their quantity in the stage, 2 days and 14 days after irradiation. There is increase in the quantity of elastic fibers in the late stage, 90 days after irradiation, tending to normality. In this present study, the changes described are not accompanied by venous

  7. Radiation effects at the SSC

    Energy Technology Data Exchange (ETDEWEB)

    Gilchriese, M.G.D. [ed.] [Superconducting Super Collider Lab., Dallas, TX (United States)

    1988-06-01

    This report contains a preliminary study of the effects of the radiation levels expected at the SSC on potential detector components and a subset of materials to be used in the SSC accelerators. The report does not contain a discussion of radiation damage to electronics components that may be used at the SSC. We have investigated many of the effects of radiation on silicon detectors, on wire chambers, on scintillating materials and the associated readout, on optical fibers for data transmission and on structural or other materials to be used in detector or accelerator components. In the SSC accelerator complex, in particular the storage rings, radiation damage will not present significant problems different than those now faced by existing high energy accelerators. We find that the effects of radiation damage on SSC detector components will be significant at the design luminosity of the ssc and will limit, or determine, many of the options for different detector components. In this regard the reader should keep in mind that, in the absence of a specific detector design, it is not possible to form definitive conclusions regarding the viability of the detector components. Since the radiation levels in experiments at the SSC will depend on the geometry and composition of the apparatus, simple yes /no generalizations about the feasibility of a detector component are not possible.

  8. Fundamental radiation effects in αAg-Zn alloys: Zener relaxation, study of the mobility of point defects and the evolution of their populations in a particle flux

    International Nuclear Information System (INIS)

    Halbwachs, Michel.

    1977-01-01

    After a recall on the physical effects of radiations, a model used to describe the defect populations produced in a fast particle flux is presented. The experimental devices used and the measurements carried out on a solid solution of αAg-Zn are described. The results obtained in an electron flux are compared with the forecastings of the theoretical models. The mobility and the apparent recombination radius of vacancies and autointerstitials, the absorption efficiency of dislocations in regard to point defects and the participation of autointerstitials to short-range order are studied. A similar study carried out under neutron irradiation is reported. The influence of neutron doses and temperature on atomic mobility is investigated. An experiment carried out under gamma photon irradiation enables a comparison to be made between the creation of defects by gamma photons and electrons [fr

  9. Radiation effect of radioiodide therapy on the hypophyseal and hypothalamic feedback control centers for thyroid function studied by dry-mount autoradiography. Final technical report

    International Nuclear Information System (INIS)

    Stumpf, W.E.

    1972-01-01

    Results are reported from studies in rats on the effects of β radiation from therapeutic doses of 131 I on the physiology of the pituitary gland and on brain structures considered thyroid hormone control areas. Iodine-125-labeled triiodothyronine and thyroxine and autoradiographic techniques were used to determine the cellular and subcellular localization of thyroid hormones in the brain tissues of untreated and thyroidectomized animals. The results suggest that thyroid hormones act on all neurons throughout the mature brain. (U.S.)

  10. Study of the radiation effects on nucleic acids and related compounds. Three year progress report, 15 August 1972--14 August 1975

    International Nuclear Information System (INIS)

    Wang, S.Y.

    1975-01-01

    Research in this project has proceeded with the chemical objective of isolating and characterizing radiation products and with the biological objective of determining the action of reactive radiation products on and in biological systems. Study has also been made on the simulation of γ radiation by various photochemical reaction conditions. Progress is reported in the chemical studies on the isolation and characterization of thymine glycols, isolation and characterization of glycols of 1-carbamylimidazolidone as products of cytosine, identification of the major hydroperoxy thymine (T 6 OOH), attempted synthesis of the nucleoside and nucleotide of T 6 OOH, and synthesis and characterization of 5-hydroperoxy-methyluracil. Progress is reported in the biological studies on the effects of T 6 OOH on nucleic acid components, on C--N glycosidic bonds, as a chemical mutagen, on the chromosomes of cells, and as a potential synergist of ionizing radiation. The photoproducts of uracil, cytosine, thymine, and thymidine that have been isolated and characterized are tabulated. (U.S.)

  11. Radiation effects on biochemical systems

    International Nuclear Information System (INIS)

    Seddon, G.M.

    2000-04-01

    Xanthine oxidase catalyses the oxidative hydroxylation of hypoxanthine, xanthine and a wide range of carbonyl compounds. The enzyme exists as an oxidase and a dehydrogenase; both catalyze the oxidation of the same substrates. Steady state radiolysis and pulse radiolysis were used to generate oxidative and reductive free radicals. Their effects on the enzymatic activity of xanthine oxidase were determined. Initially inactivation studies were carried out to evaluate the extent to which radiolysis in aqueous solution affects the enzyme activity. Values of D 37 and G inactivation were calculated following irradiation in the presence of free radical scavengers and in the presence of catalase and superoxide dismutase. The kinetic constants Vmax and Km were also determined following radiolysis. The effect of ionising radiation on the iron content of xanthine oxidase was measured using atomic absorption spectrometry. Native gel electrophoresis and iso-electric focussing were performed in an attempt to demonstrate changes in the overall structure of the enzyme. The binding of xanthine oxidase to heparin was carried out by measuring, (1) the displacement of methylene blue (MB + ) from a heparin-MB + complex, (2) affinity chromatography and, (3) pulse radiolysis. The effect of irradiation on the binding process was investigated using techniques (1) and (2). Finally the radiation-induced conversion of xanthine oxidase to dehydrogenase was established. The results indicate that xanthine oxidase is inactivated greatest in the presence of air and irradiation causes Vmax to he reduced and Km to increase. The iron content of irradiated xanthine oxidase is unaffected. Electrophoresis shows the enzyme becomes fragmented and the isoelectric points of the fragments vary over a wide range of pH. Binding of xanthine oxidase to heparin as measured by displacement of MB + from a heparin-MB + complex suggests that irradiation increases the affinity of the enzyme for the polyanion, whereas

  12. Ionising radiation effects on food packaging

    International Nuclear Information System (INIS)

    Ragni, P.; Segre, A. L.; Capitani, D.; Danesi, P.R.

    2001-01-01

    The main aim of any food irradiation treatment is to guarantee the best safe quality of the products, reducing the spreading risk ( c ross-contamination ) for several food-associated diseases. Actually, over 40 countries provide clearances for the treatment of about 45 different types of foodstuffs. EU has to homogenise the situation within the associated States. With the European directive 1999/2/EC Italy, as other EU countries, already has brought into force their regulations to comply. The current Italian regulation on irradiation treatment of foodstuffs is referred since 1996 as follows: a) potatoes, onions and garlic; b) spices, herbs and condiments microbial. The new (April 2001) Italian law allows the possibility to ask for special permission of treatment for other foodstuff which is possible to treat in other E.U. countries. Large majority of foods are submitted to irradiation treatment after they have been packaged. In Dutch cases the study of radiation effects on the package becomes crucial, also because polymeric materials may be affected by ionizing radiation. We performed our studies on several materials employed in food packaging, with a particular care to the role of anti-oxidant additives present in food packaging materials. The attention is pointed on the possible chemical-physical effects induced by radiation on foodstuff packaging. After irradiation in plastic materials two main effects may occur: degradation and cross-linking. The result depending on the comparative rates of the two actions. This kind of information was successfully obtained using NMR methods on a large number of polymers effectively used for the food packaging procedures

  13. Genomic instability and radiation effects

    International Nuclear Information System (INIS)

    Christian Streffer

    2007-01-01

    malformations) develop by going through several mutation steps, an increase of genomic instability can have the consequence that the probability for the necessary mutation steps after the initiation processes will be enhanced and facilitated. In this connection it is of high interest that genomic instability is increased in several human populations who have developed or will develop a cancer with/or without radiation. The genomic instability was studied in peripheral lymphocytes of these patients. Such an effect has been found in patients with head and neck cancers before treatment. It has been observed in uranium miners and patients with Morbus Hodgkin who developed secondary cancers after exposures. The implications of these phenomena for low dose radiation seem to be important.

  14. Environmental Radiation Effects on Mammals A Dynamical Modeling Approach

    CERN Document Server

    Smirnova, Olga A

    2010-01-01

    This text is devoted to the theoretical studies of radiation effects on mammals. It uses the framework of developed deterministic mathematical models to investigate the effects of both acute and chronic irradiation in a wide range of doses and dose rates on vital body systems including hematopoiesis, small intestine and humoral immunity, as well as on the development of autoimmune diseases. Thus, these models can contribute to the development of the system and quantitative approaches in radiation biology and ecology. This text is also of practical use. Its modeling studies of the dynamics of granulocytopoiesis and thrombocytopoiesis in humans testify to the efficiency of employment of the developed models in the investigation and prediction of radiation effects on these hematopoietic lines. These models, as well as the properly identified models of other vital body systems, could provide a better understanding of the radiation risks to health. The modeling predictions will enable the implementation of more ef...

  15. Ab initio study of radiation effects on the Li{sub 4}Ti{sub 5}O{sub 12} electrode used in lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Samin, Adib, E-mail: Samin.2@osu.edu, E-mail: cao.152@osu.edu; Kurth, Michael; Cao, Lei, E-mail: Samin.2@osu.edu, E-mail: cao.152@osu.edu [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, 201 W 19" t" h Avenue, Columbus, Ohio 43210 (United States)

    2015-04-15

    Lithium-ion batteries are currently in wide use owing to their high energy density and enhanced capabilities. Li{sub 4}Ti{sub 5}O{sub 12} is a promising anode material for lithium-ion batteries because of its advantageous properties. Lithium-ion batteries could be exposed to radiation occurring in various conditions such as during outer space exploration and nuclear accidents. In this study, we apply density functional theory to explore the effect of radiation damage on this electrode and, ultimately, on the performance of the battery. It was found that radiation could affect the structural stability of the material. Furthermore, the electrode was shown to undergo a transition from insulator to metal, following the defects due to radiation. In addition, the effect of radiation on the intercalation potential was found to be highly dependent on the nature of the defect induced.

  16. Ab initio study of radiation effects on the Li4Ti5O12 electrode used in lithium-ion batteries

    Science.gov (United States)

    Samin, Adib; Kurth, Michael; Cao, Lei

    2015-04-01

    Lithium-ion batteries are currently in wide use owing to their high energy density and enhanced capabilities. Li4Ti5O12 is a promising anode material for lithium-ion batteries because of its advantageous properties. Lithium-ion batteries could be exposed to radiation occurring in various conditions such as during outer space exploration and nuclear accidents. In this study, we apply density functional theory to explore the effect of radiation damage on this electrode and, ultimately, on the performance of the battery. It was found that radiation could affect the structural stability of the material. Furthermore, the electrode was shown to undergo a transition from insulator to metal, following the defects due to radiation. In addition, the effect of radiation on the intercalation potential was found to be highly dependent on the nature of the defect induced.

  17. Ab initio study of radiation effects on the Li4Ti5O12 electrode used in lithium-ion batteries

    International Nuclear Information System (INIS)

    th Avenue, Columbus, Ohio 43210 (United States))" data-affiliation=" (Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, 201 W 19th Avenue, Columbus, Ohio 43210 (United States))" >Samin, Adib; th Avenue, Columbus, Ohio 43210 (United States))" data-affiliation=" (Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, 201 W 19th Avenue, Columbus, Ohio 43210 (United States))" >Kurth, Michael; th Avenue, Columbus, Ohio 43210 (United States))" data-affiliation=" (Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, 201 W 19th Avenue, Columbus, Ohio 43210 (United States))" >Cao, Lei

    2015-01-01

    Lithium-ion batteries are currently in wide use owing to their high energy density and enhanced capabilities. Li 4 Ti 5 O 12 is a promising anode material for lithium-ion batteries because of its advantageous properties. Lithium-ion batteries could be exposed to radiation occurring in various conditions such as during outer space exploration and nuclear accidents. In this study, we apply density functional theory to explore the effect of radiation damage on this electrode and, ultimately, on the performance of the battery. It was found that radiation could affect the structural stability of the material. Furthermore, the electrode was shown to undergo a transition from insulator to metal, following the defects due to radiation. In addition, the effect of radiation on the intercalation potential was found to be highly dependent on the nature of the defect induced

  18. Utilization of rice husk ash as filler for polyamide 6 and ionizing radiation effect studies on this composite;Utilizacao da cinza da casca de arroz como carga em matriz de poliamida 6 submetida a radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Ferro, Waldir Pedro

    2009-07-01

    In order to improve the dimensional stability, as well as, electrical, mechanical and thermal properties of polymers, new filler to this purpose has been developed. The mos applied filler to propitiate the features previously mentioned are the glass and carbon fibers, the mineral filler as the calcium carbonate, the talc and the micro glass sphere. The main aim of this work was to study the rice husk ash as filler for polyamide 6 and ionizing radiation effect studies on this composite, irradiated by electron beam at different doses, since it is constituted of at least 90% of silicon dioxide, and compared with the talc which is the most applied mineral filler. This comparison was made from a compound made through the refined rice husk ash and the polyamide 6 (PA 6), which is one of the main engineering plastic with applications in several productive areas. The samples were injected and irradiated in a electron accelerator. Afterwards, their mechanical and thermal properties were measured. It was also inject automotive parts to verify the processing of the PA 6 with CCA. The results showed that the use of the rice husk ash as filler for polyamide 6 composite is technically and economically viable. The irradiation of the studied composite (PA 6 with 30% of rice husk ash) did not provide any improvement for the mechanical and thermal properties previously appraised. (author)

  19. Gamma radiation effects in vertically aligned carbon nanotubes

    OpenAIRE

    Lubkowski, Grzegorz; Kuhnhenn, Jochen; Suhrke, Michael; Weinand, Udo; Endler, Ingolf; Meißner, Frank; Richter, Sylvia

    2011-01-01

    This paper describes an experimental study of gamma radiation effects in low-density arrays of vertically aligned carbon nanotubes. These arrays are characterized by excellent anti-reflective and absorbing properties for wavelengths from UV to IR, which makes them an interesting option for stray light control in optical space applications. Gamma irradiation equivalent to an estimated surface lifetime exposition in geostationary orbit does not affect the reflectivity of the structures. First h...

  20. Gamma radiation effects on different sorts of onions

    International Nuclear Information System (INIS)

    Burov, B.A.

    1977-01-01

    Gamma radiation effects on different sorts of onions were studied to improve ways of obtaining agricultural vegetation mutations and to find out the genotype role in induced mutagenesis. It is established that rhizome onion seeds are more radiosensitive than bulbous ones, ephemeroide form seeds are most stable among bulbous plants. Table data on dependence of seed germination and plant survival on radiation dose are presented

  1. Lifetime radiation effects research in animals: An overview of the status and philosophy of studies at University of California-Davis Laboratory for Energy-Related Health Research

    International Nuclear Information System (INIS)

    Goldman, M.; Rosenblatt, L.S.; Book, S.A.

    1986-01-01

    Studies on the life-shortening and carcinogenic effects of internal emitters and external irradiation have been conducted at the Laboratory for Energy-Related Health Research for over three decades. Our principal animal model has been the beagle dog. The beagle's tissue sensitivity, metabolic and dosimetric characteristics, pathologic responses, and aging changes give it relevance for the assessment of radiation risks in humans. Although our results confirm the existence of an amelioration of effects at low doses and low dose rates (the dose-rate effectiveness factor), the manifestation of the amelioration may vary. For example, with x-irradiation higher exposures appeared to decrease latency but did not alter the incidence of mammary cancer, whereas with the bone-seeking radionuclides, 90 Sr and 226 Ra, higher doses decreased the latency and increased the incidence of osteosarcomas. Radiation-induced leukemias were seen only with high doses at high dose rates but only from 90 Sr and from chronic exposures to 60 Co, mainly in dogs exposed beginning in utero. Most of the radiation-induced life shortening in dogs exposed to internal emitters appears attributable to an increased cancer risk, but this is not necessarily the case for x-irradiated dogs

  2. Aerosol radiative effects over BIMSTEC regions

    Science.gov (United States)

    Kumar, Sumit; Kar, S. C.; Mupparthy, Raghavendra S.

    Aerosols can have variety of shapes, composition, sizes and other properties that influence their optical characteristics and thus the radiative impact. The visible impact of aerosol is the formation of haze, a layer of particles from vehicular, industrial emissions and biomass burning. The characterization of these fine particles is important for regulators and researchers because of their potential impact on human health, their ability to travel thousands of kilometers crossing international borders, and their influence on climate forcing and global warming. The Bay of Bengal Initiative for Multi-Sectoral Technical and Economic Cooperation (BIMSTEC) with Member Countries Bangladesh, Bhutan, India, Myanmar, Nepal, Sri Lanka and Thailand has emerged as an important regional group for technical and economic Cooperation. Continuing the quest for a deeper understanding of BIMSTEC countries weather and climate, in this paper we focused on aerosols and their direct radiative effects. Because of various contrasts like geophysical, agricultural practices, heterogeneous land/ocean surface, population etc these regions present an excellent natural laboratory for studying aerosol-meteorology interactions in tropical to sub-tropical environments. We exploited data available on multiple platforms (such as MISR, MODIS etc) and models (OPAC, SBDART etc) to compute the results. Ten regions were selected with different surface characteristics, also having considerable differences in the long-term trends and seasonal distribution of aerosols. In a preliminary analysis pertaining to pre-monsoon (March-April-May) of 2013, AOD _{555nm} is found to be maximum over Bangladesh (>0.52) and minimum over Bhutan (0.22), whereas other regions have intermediate values. Concurrent to these variability of AOD we found a strong reduction in incoming flux at surface of all the regions (> -25 Wm (-2) ), except Bhutan and Sri Lanka (< -18Wm (-2) ). The top of the atmosphere (TOA) forcing values are

  3. Radiation-induced polymerization and radiation effect on polymers

    International Nuclear Information System (INIS)

    Seguchi, Tadao

    1977-12-01

    The processes of radiation-induced polymerization of monomers and also radiation effects on polymers have been studied by instrumental analyses of electron spin resonance (ESR), nuclear magnetic resonance (NMR) and electron microscopy. In radiation-induced polymerization, graft-copolymerization and absorbed state polymerization were taken up. For graft-copolymerization, monomers such as methylmethacrylate and butadiene were made to react with irradiated polyethylene, and behaviors of the initiating radicals and propagating radicals were followed under the reaction by ESR. For absorbed state polymerization, acrylonitrile/zeolite and methylmethacrylate/zeolite were chosen. Absorbed monomers were irradiated at 77 0 K and polymerized at room temperature. Active species and the concentrations were measured by ESR and the yields of polymer were observed by NMR. In radiation effect on polymers, polyvinylfluoride, polyvinylidenfluoride and polytetrafluoroethylene were taken up. Active species trapped in the polymer matrixes were identified and decay and reactivity of the species were also studied. On the basis of information from the electron microscopy and x-ray analysis, radiation effects on these polymers are described. In polytetrafluoroethylene produced by radiation polymerization, the relation between morphology and polymerization conditions and also the process of crystallization during polymerization were studied. (auth.)

  4. Anti-radiation effect of hericium erinaceus polysaccharide

    International Nuclear Information System (INIS)

    Liu Shuchen; Zhang Huijuan; Luo Chuanhuan; Wang Bingji

    1999-01-01

    Objective: To study the anti-radiation effect of hericium erinaceus polysaccharide on irradiated mice. Methods: 520 female mice were randomized to several groups and exposed to 6.25-8.5 Gy whole-body γ-rays. The hericium erinaceus polysaccharide was injected i.p before or after irradiation. The 30-day survival rate of mice was determined, and DNA content of bone marrow was observed as well at seventh day after irradiation. Results: It was showed that the 30-day survival rate and DNA content of bone marrow were all significantly higher in 30 mg or 15 mg hericium erinaceus polysaccharide-treated groups than those in the corresponding irradiated controls (P < 0.01). The 30-day survival rate increased from 35% to 97.5%. Conclusion: The hericium erinaceus polysaccharide has marked anti-radiation effect. Further investigation is worthwhile

  5. A Study of Laughter in Science Lessons

    Science.gov (United States)

    Roth, Wolff-Michael; Ritchie, Stephen M.; Hudson, Peter; Mergard, Victoria

    2011-01-01

    Laughter is a fundamental human phenomenon. Yet there is little educational research on the potential functions of laughter on the enacted (lived) curriculum. In this study, we identify the functions of laughter in a beginning science teacher's classroom throughout her first year of teaching. Our study shows that laughter is more than a gratuitous…

  6. African Journal of Educational Studies in Mathematics and Sciences

    African Journals Online (AJOL)

    African Journal of Educational Studies in Mathematics and Sciences. ... Studies in Mathematics and Sciences (AJESMS) is an international publication that ... in the fields of mathematics education, science education and related disciplines.

  7. Study of radiation effects on semiconductor devices

    International Nuclear Information System (INIS)

    Kuboyama, Satoshi; Shindou, Hiroyuki; Ikeda, Naomi; Iwata, Yoshiyuki; Murakami, Takeshi

    2004-01-01

    Fine structure of the recent semiconductor devices has made them more sensitive to the space radiation environment with trapped high-energy protons and heavy ions. A new failure mode caused by bulk damage had been reported on such devices with small structure, and its effect on commercial synchronous dynamic random access memory (SDRAMs) was analyzed from the irradiation test results performed at Heavy ion Medical Accelerator in Chiba (HIMAC). Single event upset (SEU) data of static random access memory (SRAMs) were also collected to establish the method of estimating the proton-induced SEU rate from the results of heavy ion irradiation tests. (authors)

  8. The radiation effects on the living cell

    International Nuclear Information System (INIS)

    Sage, E.; Dutrillaux, B.; Soussi, Th.; Boiteux, S.; Lopez, B.; Feunteun, J.

    1999-06-01

    This publication is a presentation of particular points discussed during the colloquium of the 15-18 june 1999, for which scientific researches are performed at the CEA/CNRS. They deal with the radiobiology, for the radiation effects on living matter; with the DNA, for the knowledge and repair mechanisms on cells submitted to ionizing radiations; with the exposition to UV in correlation with neoplasms; with the P53 gene which is a tumour suppressor. (A.L.B.)

  9. Advanced CMOS Radiation Effects Testing and Analysis

    Science.gov (United States)

    Pellish, J. A.; Marshall, P. W.; Rodbell, K. P.; Gordon, M. S.; LaBel, K. A.; Schwank, J. R.; Dodds, N. A.; Castaneda, C. M.; Berg, M. D.; Kim, H. S.; hide

    2014-01-01

    Presentation at the annual NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop (ETW). The material includes an update of progress in this NEPP task area over the past year, which includes testing, evaluation, and analysis of radiation effects data on the IBM 32 nm silicon-on-insulator (SOI) complementary metal oxide semiconductor (CMOS) process. The testing was conducted using test vehicles supplied by directly by IBM.

  10. Radiation effects of high and low doses

    International Nuclear Information System (INIS)

    El-Naggar, A.M.

    1998-01-01

    The extensive proliferation of the uses and applications of atomic and nuclear energy resulted in possible repercussions on human health. The prominent features of the health hazards that may be incurred after exposure to high and low radiation doses are discussed. The physical and biological factors involved in the sequential development of radiation health effects and the different cellular responses to radiation injury are considered. The main criteria and features of radiation effects of high and low doses are comprehensively outlined

  11. Radiation effects on light sources and detectors

    International Nuclear Information System (INIS)

    Barnes, C.E.

    1985-01-01

    The rapidly expanding field of optoelectronics includes a wide variety of both military and non-military applications in which the systems must meet radiation exposure requirements. Herein, we review the work on radiation effects on sources and detectors for such optoelectronic systems. For sources the principal problem is permanent damage-induced light output degradation, while for detectors it is ionizing radiation-induced photocurrents

  12. Radiation effects concerns at a spallation source

    International Nuclear Information System (INIS)

    Sommer, W.F.

    1990-01-01

    Materials used at spallation neutron sources are exposed to energetic particle and photon radiation. Mechanical and physical properties of these materials are altered; radiation damage on the atomic scale leads to radiation effects on the macroscopic scale. Most notable among mechanical-property radiation effects in metals and metal alloys are changes in tensile strength and ductility, changes in rupture strength, dimensional stability and volumetric swelling, and dimensional changes due to stress-induced creep. Physical properties such as electrical resistivity also are altered. The fission-reactor community has accumulated a good deal of data on material radiation effects. However, when the incident particle energy exceeds 50 MeV or so, a new form of radiation damage ensues; spallation reactions lead to more energetic atom recoils and the subsequent temporal and spatial distribution of point defects is much different from that due to a fission-reactor environment. In addition, spallation reactions cause atomic transmutations with these new atoms representing an impurity in the metal. The higher-energy case is of interest at spallation sources; limited detailed data exist for material performance in this environment. 35 refs., 13 figs., 1 tab

  13. Radiation effects on Brassica seeds and seedlings

    Science.gov (United States)

    Deoli, Naresh; Hasenstein, Karl H.

    2016-07-01

    damage. We compared curvature in untreated with irradiated roots and measured the inhibition of curvature at 2×1013 - 8×1013 ions/cm2. Despite greater mass of imbibed seeds, the dose-response curve showed greater sensitivity of imbibed than for dry seeds. In addition, germination rate was found to be strongly dependent on ion beam current, at least for 3 MeV protons. Our data show that weak ionizing particles (low MeV protons) are suitable to study radiation effects and seedlings are a useful biological systems to study space radiation. Supported by NASA grant NNX13AN05A.

  14. Nature of Science Contextualized: Studying Nature of Science with Scientists

    Science.gov (United States)

    Tala, Suvi; Vesterinen, Veli-Matti

    2015-01-01

    Understanding nature of science (NOS) is widely considered an important educational objective and views of NOS are closely linked to science teaching and learning. Thus there is a lively discussion about what understanding NOS means and how it is reached. As a result of analyses in educational, philosophical, sociological and historical research,…

  15. Biologically based multistage modeling of radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    William Hazelton; Suresh Moolgavkar; E. Georg Luebeck

    2005-08-30

    This past year we have made substantial progress in modeling the contribution of homeostatic regulation to low-dose radiation effects and carcinogenesis. We have worked to refine and apply our multistage carcinogenesis models to explicitly incorporate cell cycle states, simple and complex damage, checkpoint delay, slow and fast repair, differentiation, and apoptosis to study the effects of low-dose ionizing radiation in mouse intestinal crypts, as well as in other tissues. We have one paper accepted for publication in ''Advances in Space Research'', and another manuscript in preparation describing this work. I also wrote a chapter describing our combined cell-cycle and multistage carcinogenesis model that will be published in a book on stochastic carcinogenesis models edited by Wei-Yuan Tan. In addition, we organized and held a workshop on ''Biologically Based Modeling of Human Health Effects of Low dose Ionizing Radiation'', July 28-29, 2005 at Fred Hutchinson Cancer Research Center in Seattle, Washington. We had over 20 participants, including Mary Helen Barcellos-Hoff as keynote speaker, talks by most of the low-dose modelers in the DOE low-dose program, experimentalists including Les Redpath (and Mary Helen), Noelle Metting from DOE, and Tony Brooks. It appears that homeostatic regulation may be central to understanding low-dose radiation phenomena. The primary effects of ionizing radiation (IR) are cell killing, delayed cell cycling, and induction of mutations. However, homeostatic regulation causes cells that are killed or damaged by IR to eventually be replaced. Cells with an initiating mutation may have a replacement advantage, leading to clonal expansion of these initiated cells. Thus we have focused particularly on modeling effects that disturb homeostatic regulation as early steps in the carcinogenic process. There are two primary considerations that support our focus on homeostatic regulation. First, a number of

  16. From Science to e-Science to Semantic e-Science: A Heliosphysics Case Study

    Science.gov (United States)

    Narock, Thomas; Fox, Peter

    2011-01-01

    The past few years have witnessed unparalleled efforts to make scientific data web accessible. The Semantic Web has proven invaluable in this effort; however, much of the literature is devoted to system design, ontology creation, and trials and tribulations of current technologies. In order to fully develop the nascent field of Semantic e-Science we must also evaluate systems in real-world settings. We describe a case study within the field of Heliophysics and provide a comparison of the evolutionary stages of data discovery, from manual to semantically enable. We describe the socio-technical implications of moving toward automated and intelligent data discovery. In doing so, we highlight how this process enhances what is currently being done manually in various scientific disciplines. Our case study illustrates that Semantic e-Science is more than just semantic search. The integration of search with web services, relational databases, and other cyberinfrastructure is a central tenet of our case study and one that we believe has applicability as a generalized research area within Semantic e-Science. This case study illustrates a specific example of the benefits, and limitations, of semantically replicating data discovery. We show examples of significant reductions in time and effort enable by Semantic e-Science; yet, we argue that a "complete" solution requires integrating semantic search with other research areas such as data provenance and web services.

  17. The manufacture of system for testing static random access memory radiation effect

    International Nuclear Information System (INIS)

    Chen Rui; Yang Chen

    2008-01-01

    Space radiation effects will lead to single event upset, event latch up and other phenomena in SRAM devices. This paper introduces the hardware, software composition and related testing technology of SRAM radiation effect testing device. Through to the SRAM chip current detection and power protection, it has solved the SRAM chip damage question in the SRAM experiment. It has accessed to the expected experimental data by using the device in different source of radiation conducted on SRAM Experimental study of radiation effects. It provides important references in the assessment of operational life and reinforcement of the memory carried in the satellites. (authors)

  18. Study on ionizing radiation effects in diesel and crude oil: organic compounds, hydrocarbon, sulfur and nitrogen; Estudo do efeito da radiacao ionizante em compostos organicos do diesel e do petroleo: hidrocarbonetos, sulfurados e nitrogenados

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Luana dos Santos

    2014-07-01

    Petroleum is the most important energy and pollution source in the world, nowadays. New technologies in petrochemical industry aim to minimize energy spending at the process and to reduce pollution products. Sulfur and nitrogen compounds generate environmental problems; the most relevant is air pollution that affects the population health directly. The nuclear technology has been used in environmental protection through pollutants removal by free radicals produced at action of the radiation in water molecule. The objective of this study is to evaluate the radiation effects on oil and diesel, mainly in the hydrocarbons, organic sulfur, and nitrogen compounds. It was studied a molecule model of sulfur, named benzothiophene, diesel and crude oil samples. The samples were irradiated using a Co-60 source, Gammacell type. The total sulfur concentration in the samples was determined by X-ray fluorescence spectrometry, and organic compounds were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The study of molecular model showed that 95% was degraded at 20 kGy dose rate. Irradiation at 15 kGy of absorbed dose showed some cracking in petrol hydrocarbons, however with higher doses it was observed polymerization and low efficiency of cracking. It was observed that the sulfur compounds from diesel and petroleum was efficiently reduced. The applied doses of 15 kGy and 30 kGy were the most efficient on desulfurization of petroleum, and for diesel the highest variation was observed with 30 kGy and 50 kGy of absorbed dose. The distillation and chromatographic separation using an open column with palladium chloride as stationary phase showed a preferential separation of organic sulfur compounds in petroleum. (author)

  19. New concepts of science and medicine in science and technology studies and their relevance to science education

    Directory of Open Access Journals (Sweden)

    Hsiu-Yun Wang

    2012-02-01

    Full Text Available Science education often adopts a narrow view of science that assumes the lay public is ignorant, which seemingly justifies a science education limited to a promotional narrative of progress in the form of scientific knowledge void of meaningful social context. We propose that to prepare students as future concerned citizens of a technoscientific society, science education should be informed by science, technology, and society (STS perspectives. An STS-informed science education, in our view, will include the following curricular elements: science controversy education, gender issues, historical perspective, and a move away from a Eurocentric view by looking into the distinctive patterns of other regional (in this case of Taiwan, East Asian approaches to science, technology, and medicine. This article outlines the significance of some major STS studies as a means of illustrating the ways in which STS perspectives can, if incorporated into science education, enhance our understanding of science and technology and their relationships with society.

  20. Late radiation effects in animals surviving lethal irradiation

    International Nuclear Information System (INIS)

    Dimitrov, L.A.

    1974-01-01

    Animals (rats, mice, dogs) survived lethal irradiation by means of prophylactic-therapeutic treatments or previously irradiated, were studied for late radiation effects: life span, cachexia and fat growing of hypophysical type, tissue or organ hypoplasia manifested by disturbed hemopoiesis, suppressed function of adrenal gland, etc., suppressed immune reactivity of the irradiated organism, atypical biochemical changes in DNA and protein metabolism, epilation, chronic dermatitis, ulcerations, reduced reproductivity or full sterility, damage of kidneys leading to nephrosclerosis, dishormonal states, cataracts, diffuse sclerotic processes, various kinds of malignant and non-malignant tumors. In these cases hemopoiesis compensated for a definite time peripheral blood composition, but during the late period it showed features of incompleteness: shorter life survival of erythrocytes and thrombocytes manifested by a decreased binding of labelled methionine in these blood elements, anemia and relative thrombocytopenia sometimes with an increased number of polychromatic erythrocytes in peripheral blood and a decreased number of reticulocytes at the same time; lymphopenia and relative leucopenia with an increased number of hypersegmented neutrophils. Decreased reproductivity and atypical biochemical changes available in the first generation of the irradiated animals showed the probable role of mutagenic factors in the emergence of some late radiation effects. A significant part of late radiation sequences were due to neuro-endocrine desintegrations which lead to a disturbed supply of the vessels and afterwards to their sclerosis. Some of the described late radiation effects were also observed in biological controls as festures of ageing while in irradiated animals they were manifested in an earlier period. After application of optimal amounts radioprotectors (AET, cysteamine, serotonin) a more marked protective effect is demonstrated in the early reactions (time survival

  1. Intense Ion Pulses for Radiation Effects Research

    Science.gov (United States)

    2017-04-01

    induction linear accelerator that has been developed to deliver intense, up to 50 nC/pulse/mm2, sub-ns pulses of light ions with kinetic energy up to 1.2...II induction linear accelerator for intense ion beam pulses at Berkeley Lab. Figure 3. Helium current and integrated charge versus time at the...under contracts DE-AC02-205CH11231 and DE-AC52-07NA27344. JOURNAL OF RADIATION EFFECTS, Research and Engineering Vol. 35, No. 1, April 2017 158 INTENSE

  2. Do compulsory secondary science courses change students’ attitude towards studying science?

    DEFF Research Database (Denmark)

    Kristensen, Lærke Elisabeth; Petersen, Morten Rask

    2015-01-01

    recruitment to STEM education has been a compulsory course in the Gymnasium called Natural Science Subject (NSS). This is an interdisciplinary, introductory course with the intention that students shall “ … realize the importance of knowing and understanding natural science thinking” (Authors translation...... science and science careers. In this approach we ended up with the following research question: “Does a compulsory introductory sciences course have an impact on students’ attitude towards studying sciences in secondary school?” In this approach we chose to use parameters as motivation (Deci & Ryan, 2002...... Subject course. The distribution included all levels (K10-K12) and all study lines. Student answers were analyzed using Mann-Whitney U-test using SPSS statistics 22 as analytical tool. Comparisons for this study were made across study lines (natural science vs. human science & social science...

  3. When Science Studies Religion: Six Philosophy Lessons for Science Classes

    Science.gov (United States)

    Pigliucci, Massimo

    2013-01-01

    It is an unfortunate fact of academic life that there is a sharp divide between science and philosophy, with scientists often being openly dismissive of philosophy, and philosophers being equally contemptuous of the naivete of scientists when it comes to the philosophical underpinnings of their own discipline. In this paper I explore the…

  4. A critical review of radiation effects on borosilicate glasses

    International Nuclear Information System (INIS)

    Lanza, F.; Manara, A.; Rutten, F. van

    1981-01-01

    Most of the experimental values have been obtained by loading the glass with alpha emitters like Cm 244 and Pu 238. The data existing in literature on stored energy, and density variation are presented and discussed. Attention is given to the variation of the leaching rate due to the radiation effect. Samples loaded with alpha emitters have given data up to 0.17 dpa and such bombarded with heavy ions show large effects due to dose rate effects. A study on defect formation has shown that under electrons irradiation, formation of bubbles is possible. (DG)

  5. Late radiation effects in animals surviving lethal irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrov, L A

    1974-01-01

    Animals (rats, mice, dogs) survived lethal irradiation by means of prophylactic-therapeutic treatments or previously irradiated, were studied for late radiation effects: life span, cachexia and fat growing of hypophysical type, tissue or organ hypoplasia manifested by disturbed hemopoiesis, suppressed function of adrenal gland, etc., suppressed immune reactivity of the irradiated organism, atypical biochemical changes in DNA and protein metabolism, epilation, chronic dermatitis, ulcerations, reduced reproductivity or full sterility, damage of kidneys leading to nephrosclerosis, dishormonal states, cataracts, diffuse sclerotic processes, various kinds of malignant and non-malignant tumors. In these cases hemopoiesis compensated for a definite time peripheral blood composition, but during the late period it showed features of incompleteness: shorter life survival of erythrocytes and thrombocytes manifested by a decreased binding of labelled methionine in these blood elements, anemia and relative thrombocytopenia sometimes with an increased number of polychromatic erythrocytes in peripheral blood and a decreased number of reticulocytes at the same time; lymphopenia and relative leucopenia with an increased number of hypersegmented neutrophils. Decreased reproductivity and atypical biochemical changes available in the first generation of the irradiated animals showed the probable role of mutagenic factors in the emergency of some late radiation effects. A significant part of late radiation sequences were due to neuro-endocrine disintegrations. Some of the described late radiation effects were also observed in biological controls as features of ageing. After application of radioprotectors (AET, cysteamine, serotonin) a more marked protective effect is demonstrated in the early reactions (time survival till 30th day, DNA and protein metabolism, immune reactions) of the lethally irradiated animals.

  6. Studying Students' Science Literacy: Non-Scientific Beliefs and Science Literacy Measures

    Science.gov (United States)

    Impey, C.; Buxner, S.

    2015-11-01

    We have been conducting a study of university students' science literacy for the past 24 years. Based on the work of the National Science Board's ongoing national survey of the US public, we have administered the same survey to undergraduate science students at the University of Arizona almost every year since 1989. Results have shown relatively little change in students' overall science literacy, descriptions of science, and knowledge of basic science topics for almost a quarter of a century despite an increase in education interventions, the rise of the internet, and increased access to knowledge. Several trends do exist in students' science literacy and descriptions of science. Students who exhibit beliefs in non-scientific phenomenon (e.g., lucky numbers, creationism) consistently have lower science literacy scores and less correct descriptions of scientific phenomenon. Although not surprising, our results support ongoing efforts to help students generate evidence based thinking.

  7. Simulation of first-wall radiation effects

    International Nuclear Information System (INIS)

    Logan, C.M.; Anderson, J.D.; Hansen, L.F.

    1975-01-01

    Many of the effects induced in metals as a result of exposure to a radiation environment are intimately associated with the energy of primary recoil atoms (PKAs). Protons with an energy of 16 MeV closely reproduce the PKA energy spectrum which will be present at the first wall in a D--T fusion reactor and should therefore closely reproduce the radiation effects induced by PKAs in the first wall. A preliminary experiment with protons was conducted to measure the sputtering rate and to look for the phenomenon of chunk emission recently observed by Kaminsky and co-workers in samples exposed to 14-MeV neutrons. We are also able to observe the average projected transport range of activated PKAs. (U.S.)

  8. Radiation effects on cultured human lymphoid cells

    International Nuclear Information System (INIS)

    Johansson, L.; Nilsson, K.; Carlsson, J.; Larsson, B.; Jakobsson, P.

    1981-01-01

    The cloning efficiency of human normal and malignant lymphoid cells is usually low. Radiation effects in vitro on such cells can therefore not be analysed with conventional cloning. However, this problem can be circumscribed by using the growth extrapolation method. A panel of human leukemia-lymphoma cell-lines representing Epstein-Barr virus carrying lymphoblastoid cells of presumed non-neoplastic derivation and neoplastic T- and B-lymphocytes was used to test the efficiency of this method. The sensitivity to radiation could be determined for all these cell types. The growth extrapolation method gave generally the same result as conventional cloning demonstrated by comparison with one exceptional cell-line with capacity for cloning in agar. The sensitivity varied largely between the different cell types. A common feature was that none of the cell lines had a good capacity to accumulate sublethal radiation injury. (Auth.)

  9. Ceramics radiation effects issues for ITER

    International Nuclear Information System (INIS)

    Zinkle, S.J.

    1993-01-01

    The key radiation effects issues associated with the successful operation of ceramic materials in components of the planned International Thermonuclear Experimental Reactor (ITER) are discussed. Radiation-induced volume changes and degradation of the mechanical properties should not be a serious issue for the fluences planned for ITER. On the other hand, radiation-induced electrical degradation effects may severely limit the allowable exposure of ceramic insulators. Degradation of the loss tangent and thermal conductivity may also restrict the location of some components such as ICRH feedthrough insulators to positions far away from the first wall. In-situ measurements suggest that the degradation of physical properties in ceramics during irradiation is greater than that measured in postirradiation tests. Additional in-situ data during neutron irradiation are needed before engineering designs for ITER can be finalized

  10. Radiation effects on structural ceramics in fusion

    International Nuclear Information System (INIS)

    Hopkins, G.R.; Price, R.J.; Trester, P.W.

    1986-01-01

    Ceramics are required to serve in a conventional role as electrical and thermal insulators and dielectrics in fusion power reactors. In addition, certain ceramic materials can play a unique structural role in fusion power reactors by virtue of their very low induced radioactivity from fusion neutron capture. The aspects of safety, long-term radioactive waste management, and personnel access for maintenance and repair can all be significantly improved by applying the low-activation ceramics to the structural materials of the first-wall and blanket regions of a fusion reactor. Achievement of long service life at high structural loads and thermal stresses on the materials exposed to high-radiation doses presents a critical challenge for fusion. In this paper, we discuss radiation effects on structural ceramics for fusion application

  11. Radiation effects on active pixel sensors (APS)

    International Nuclear Information System (INIS)

    Cohen, M.; David, J.P.

    1999-01-01

    Active pixel sensor (APS) is a new generation of image sensors which presents several advantages relatively to charge coupled devices (CCDs) particularly for space applications (APS requires only 1 voltage to operate which reduces considerably current consumption). Irradiation was performed using 60 Co gamma radiation at room temperature and at a dose rate of 150 Gy(Si)/h. 2 types of APS have been tested: photodiode-APS and photoMOS-APS. The results show that photoMOS-APS is more sensitive to radiation effects than photodiode-APS. Important parameters of image sensors like dark currents increase sharply with dose levels. Nevertheless photodiode-APS sensitivity is one hundred time lower than photoMOS-APS sensitivity

  12. Reliability and radiation effects in compound semiconductors

    CERN Document Server

    Johnston, Allan

    2010-01-01

    This book discusses reliability and radiation effects in compound semiconductors, which have evolved rapidly during the last 15 years. Johnston's perspective in the book focuses on high-reliability applications in space, but his discussion of reliability is applicable to high reliability terrestrial applications as well. The book is important because there are new reliability mechanisms present in compound semiconductors that have produced a great deal of confusion. They are complex, and appear to be major stumbling blocks in the application of these types of devices. Many of the reliability problems that were prominent research topics five to ten years ago have been solved, and the reliability of many of these devices has been improved to the level where they can be used for ten years or more with low failure rates. There is also considerable confusion about the way that space radiation affects compound semiconductors. Some optoelectronic devices are so sensitive to damage in space that they are very difficu...

  13. African Journal of Educational Studies in Mathematics and Sciences ...

    African Journals Online (AJOL)

    African Journal of Educational Studies in Mathematics and Sciences: Advanced Search. Journal Home > African Journal of Educational Studies in Mathematics and Sciences: Advanced Search. Log in or Register to get access to full text downloads.

  14. Science Fiction: Better than Delphi Studies.

    Science.gov (United States)

    Wolf, Milton T.

    1994-01-01

    Considers science fiction as a literary genre and as a predictor of technological advances, particularly in the information industry. An annotated bibliography is included of 11 science fiction titles and 1 nonfiction book that suggest possible information futures. (LRW)

  15. Reel Science: An Ethnographic Study of Girls' Science Identity Development in and through Film

    Science.gov (United States)

    Chaffee, Rachel L.

    2016-01-01

    This dissertation study contributes to the research on filmmaking and identity development by exploring the ways that film production provided unique opportunities for a team of four girls to engage in science, to develop identities in science, and to see and understand science differently. Using social practice, identity, and feminist theory and…

  16. Reel Science: An Ethnographic Study of Girls' Science Identity Development In and Through Film

    Science.gov (United States)

    Chaffee, Rachel L.

    This dissertation study contributes to the research on filmmaking and identity development by exploring the ways that film production provided unique opportunities for a team of four girls to engage in science, to develop identities in science, and to see and understand science differently. Using social practice, identity, and feminist theory and New Literacies Studies as a theoretical lens and grounded theory and multimodality as analytic frameworks, I present findings that suggest that girls in this study authored identities and communicated and represented science in and through film in ways that drew on their social, cultural, and embodied resources and the material resources of the after-school science club. Findings from this study highlight the affordances of filmmaking as a venue for engaging in the disciplinary practices of science and for accessing and authoring identities in science.

  17. 78 FR 33074 - Army Science Board Summer Study Session

    Science.gov (United States)

    2013-06-03

    ...--This study evaluates what science and technology competencies the Army must maintain and/or develop as... DEPARTMENT OF DEFENSE Department of the Army Army Science Board Summer Study Session AGENCY... the Army announces the following committee meeting: 1. Name of Committee: Army Science Board (ASB). 2...

  18. Potential pre-cataractous markers induced by low-dose radiation effects in cultured human lens cells

    Science.gov (United States)

    Blakely, E.; McNamara, M.; Bjornstad, K.; Chang, P.

    The human lens is one of the most radiosensitive organs of the body. Cataract, the opacification of the lens, is a late-appearing response to radiation damage. Recent evidence indicates that exposure to relatively low doses of space radiation are associated with an increased incidence and early appearance of human cataracts (Cucinotta et al., Radiat. Res. 156:460-466, 2001). Basic research in this area is needed to integrate the early responses of various late-responding tissues into our understanding and estimation of radiation risk for space travel. In addition, these studies may contribute to the development of countermeasures for the early lenticular changes, in order to prevent the late sequelae. Radiation damage to the lens is not life threatening but, if severe, can affect vision unless surgically corrected with synthetic lens replacement. The lens, however, may be a sensitive detector of radiation effects for other cells of ectodermal origin in the body for which there are not currently clear endpoints of low-dose radiation effects. We have investigated the dose-dependent expression of several radiation-responsive endpoints using our in vitro model of differentiating human lens epithelial cells (Blakely et al., Investigative Ophthalmology &Visual Sciences, 41(12):3898-3907, 2000). We have investigated radiation effects on several gene families that include, or relate to, DNA damage, cytokines, cell-cycle regulators, cell adhesion molecules, cell cytoskeletal function and apoptotic cell death. In this paper we will summarize some of our dose-dependent data from several radiation types, and describe the model of molecular and cellular events that we believe may be associated with precataractous events in the human lens after radiation exposure. This work was supported by NASA Grant #T-965W.

  19. Science comics as tools for science education and communication: a brief, exploratory study

    Directory of Open Access Journals (Sweden)

    M. Tatalovic

    2009-11-01

    Full Text Available Comics are a popular art form especially among children and as such provide a potential medium for science education and communication. In an attempt to present science comics in a museum exhibit I found many science themed comics and graphic books. Here I attempt to provide an overview of already available comics that communicate science, the genre of ‘science comics’. I also provide a quick literature review for evidence that comics can indeed be efficiently used for promoting scientific literacy via education and communication. I address the issue of lack of studies about science comics and their readers and suggest some possible reasons for this as well as some questions that could be addressed in future studies on the effect these comics may have on science communication.

  20. Radiation effects on superconducting fusion magnet components

    International Nuclear Information System (INIS)

    Weber, H.W.

    2011-01-01

    Nuclear fusion devices based on the magnetic confinement principle heavily rely on the existence and performance of superconducting magnets and have always significantly contributed to advancing superconductor and magnet technology to their limits. In view of the presently ongoing construction of the tokamak device ITER and the stellerator device Wendelstein 7X and their record breaking parameters concerning size, complexity of design, stored energy, amperage, mechanical and magnetic forces, critical current densities and stability requirements, it is deemed timely to review another critical parameter that is practically unique to these devices, namely the radiation response of all magnet components to the lifetime fluence of fast neutrons and gamma rays produced by the fusion reactions of deuterium and tritium. I will review these radiation effects in turn for the currently employed standard "technical" low temperature superconductors NbTi and Nb 3 Sn, the stabilizing material (Cu) as well as the magnet insulation materials and conclude by discussing the potential of high temperature superconducting materials for future generations of fusion devices, such as DEMO. (author)

  1. Radiative effects of global MODIS cloud regimes

    Science.gov (United States)

    Oreopoulos, Lazaros; Cho, Nayeong; Lee, Dongmin; Kato, Seiji

    2018-01-01

    We update previously published MODIS global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 dataset. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux datasets. Our results clearly show the CRs are radiatively distinct in terms of shortwave, longwave and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance datasets suffering from imperfect spatiotemporal matching depend on CR, and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations. PMID:29619289

  2. The Radiation Effect on Peripheral Blood Cell

    International Nuclear Information System (INIS)

    Lee, Tae June; Kwon, Hyoung Cheol; Kim, Jung Soo; Im, Sun Kyun; Choi, Ki Chul

    1988-01-01

    To evaluate radiation effect on the hematopoietic system, we analyzed 44 patients who were treated with conventionally fractionated radiation therapy (RT) at Chonbuk National University Hospital. According to the treatment sites, we classified them into three groups: group I as head and neck, group II as thorax, and group III as pelvis. White blood cell, lymphocyte, platelet and hemoglobin were checked before and during RT The results were as follow; 1. White blood cell (WBC) and lymphocyte count were declined from the first week of RT to the third week, and then slightly recovered after the third or fourth week. There was prominent decrease in lymphocyte counts than WBC. 2. Platelet counts were declined until the second week of the RT, showed slight recovery at fourth week in all groups. Hemoglobin values were slightly decreased in the first week and then recovered the level of pretreatment value, gradually. 3. Lymphocyte count were declined significantly on group III(p<0.01), WBC and platelet counts were decreased on group II but statistically not significant

  3. Radiative Effects of Global MODIS Cloud Regimes

    Science.gov (United States)

    Oraiopoulos, Lazaros; Cho, Nayeong; Lee, Dong Min; Kato, Seiji

    2016-01-01

    We update previously published MODIS global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 dataset. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux datasets. Our results clearly show the CRs are radiatively distinct in terms of shortwave, longwave and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance datasets suffering from imperfect spatiotemporal matching depend on CR, and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations.

  4. Radiation effects in IRAS extrinsic infrared detectors

    Science.gov (United States)

    Varnell, L.; Langford, D. E.

    1982-01-01

    During the calibration and testing of the Infrared Astronomy Satellite (IRAS) focal plane, it was observed that the extrinsic photoconductor detectors were affected by gamma radiation at dose levels of the order of one rad. Since the flight environment will subject the focal plane to dose levels of this order from protons in single pass through the South Atlantic Anomaly, an extensive program of radiation tests was carried out to measure the radiation effects and to devise a method to counteract these effects. The effects observed after irradiation are increased responsivity, noise, and rate of spiking of the detectors after gamma-ray doses of less than 0.1 rad. The detectors can be returned almost to pre-irradiation performance by increasing the detector bias to breakdown and allowing a large current to flow for several minutes. No adverse effects on the detectors have been observed from this bias boost, and this technique will be used for IRAS with frequent calibration to ensure the accuracy of observations made with the instrument.

  5. Radiation effects in uranium-niobium titanates

    International Nuclear Information System (INIS)

    Lian, J.; Wang, S.X.; Wang, L.M.; Ewing, R.C.

    2000-01-01

    Pyrochlore is an important actinide host phase proposed for the immobilization of high level nuclear wastes and excess weapon plutonium.[1] Synthetic pyrochlore has a great variety of chemical compositions due to the possibility of extensive substitutions in the pyrochlore structure.[2] During the synthesis of pyrochlore, additional complex titanate phases may form in small quantities. The response of these phases to radiation damage must be evaluated because volume expansion of minor phases may cause micro-fracturing. In this work, two complex uranium-niobium titanates, U 3 NbO 9.8 (U-rich titanate) and Nb 3 UO 10 (Nb-rich titanate) were synthesized by the alkoxide/nitrate route at 1300 deg. C under an argon atmosphere. The phase composition and structure were analyzed by EDS, BSE, XRD, EMPA and TEM techniques. An 800 KeVKr 2+ irradiation was performed using the IVEM-Tandem Facility at Argonne National Laboratory in a temperature range from 30 K to 973 K. The radiation effects were observed by in situ TEM

  6. Direct radiative effect due to brownness in organic carbon aerosols generated from biomass combustion

    International Nuclear Information System (INIS)

    Rathod, T.D.; Sahu, S.K.; Tiwari, M.; Pandit, G.G.

    2016-01-01

    We report the enhancement in the direct radiative effect due the presence of Brown carbon (BrC) as a part of organic carbon aerosols. The optical properties of organic carbon aerosols generated from pyrolytic combustion of mango tree wood (Magnifera Indica) and dung cake at different temperatures were considered. Mie codes were used to calculate absorption and scattering coefficients coupled with experimentally derived imaginary complex refractive index. The direct radiative effect (DRE) for sampled organic carbon aerosols was estimated using a wavelength dependent radiative transfer equation. The BrC DRE was estimated taking virtually non absorbing organic aerosols as reference. The BrC DRE from wood and dung cake was compared at different combustion temperatures and conditions. The BrC contributed positively to the direct top of the atmosphere radiative effect. Dung cake generated BrC aerosols were found to be strongly light absorbing as compared to BrC from wood combustion. It was noted that radiative effects of BrC from wood depended on its generation temperature and conditions. For BrC aerosols from dung cake such strong dependence was not observed. The average BrC aerosol DRE values were 1.53±0.76 W g"−"1 and 17.84±6.45 W g"−"1 for wood and dung cake respectively. The DRE contribution of BrC aerosols came mainly (67–90%) from visible light absorption though they exhibited strong absorption in shorter wavelengths of the UV–visible spectrum. - Highlights: • Biomass fuels (wood and dung cake) were studied for brown carbon direct radiative effects. • Model calculations predicted positive contribution of Brown carbon aerosols to organic carbon direct radiative effect. • Average direct radiative values for brown carbon from dung cake were higher compare to wood. • The visible light absorption played major role in brown carbon contribution (67–90 %) to total direct radiative effect.

  7. Negotiating science and engineering: an exploratory case study of a reform-minded science teacher

    Science.gov (United States)

    Guzey, S. Selcen; Ring-Whalen, Elizabeth A.

    2018-05-01

    Engineering has been slowly integrated into K-12 science classrooms in the United States as the result of recent science education reforms. Such changes in science teaching require that a science teacher is confident with and committed to content, practices, language, and cultures related to both science and engineering. However, from the perspective of the science teacher, this would require not only the development of knowledge and pedagogies associated with engineering, but also the construction of new identities operating within the reforms and within the context of their school. In this study, a middle school science teacher was observed and interviewed over a period of nine months to explore his experiences as he adopted new values, discourses, and practices and constructed his identity as a reform-minded science teacher. Our findings revealed that, as the teacher attempted to become a reform-minded science teacher, he constantly negotiated his professional identities - a dynamic process that created conflicts in his classroom practices. Several differences were observed between the teacher's science and engineering instruction: hands-on activities, depth and detail of content, language use, and the way the teacher positioned himself and his students with respect to science and engineering. Implications for science teacher professional development are discussed.

  8. New concepts of science and medicine in science and technology studies and their relevance to science education.

    Science.gov (United States)

    Wang, Hsiu-Yun; Stocker, Joel F; Fu, Daiwie

    2012-02-01

    Science education often adopts a narrow view of science that assumes the lay public is ignorant, which seemingly justifies a science education limited to a promotional narrative of progress in the form of scientific knowledge void of meaningful social context. We propose that to prepare students as future concerned citizens of a technoscientific society, science education should be informed by science, technology, and society (STS) perspectives. An STS-informed science education, in our view, will include the following curricular elements: science controversy education, gender issues, historical perspective, and a move away from a Eurocentric view by looking into the distinctive patterns of other regional (in this case of Taiwan, East Asian) approaches to science, technology, and medicine. This article outlines the significance of some major STS studies as a means of illustrating the ways in which STS perspectives can, if incorporated into science education, enhance our understanding of science and technology and their relationships with society. Copyright © 2011. Published by Elsevier B.V.

  9. Radiation effects in glass waste forms for high-level waste and plutonium disposal

    International Nuclear Information System (INIS)

    Weber, W.J.; Ewing, R.C.

    1997-01-01

    A key challenge in the permanent disposal of high-level waste (HLW), plutonium residues/scraps, and excess weapons plutonium in glass waste forms is the development of predictive models of long-term performance that are based on a sound scientific understanding of relevant phenomena. Radiation effects from β-decay and α-decay can impact the performance of glasses for HLW and Pu disposition through the interactions of the α-particles, β-particles, recoil nuclei, and γ-rays with the atoms in the glass. Recently, a scientific panel convened under the auspices of the DOE Council on Materials Science to assess the current state of understanding, identify important scientific issues, and recommend directions for research in the area of radiation effects in glasses for HLW and Pu disposition. The overall finding of the panel was that there is a critical lack of systematic understanding on radiation effects in glasses at the atomic, microscopic, and macroscopic levels. The current state of understanding on radiation effects in glass waste forms and critical scientific issues are presented

  10. Initial processes of radiation effects on genomic stability

    International Nuclear Information System (INIS)

    Herve du Penhoat, Marie-Anne; Touati, Alain; Sage, Evelyne; Houee-Levin, Chantal; Lacombe, Sandrine; Politis, Marie-Françoise; Gaigeot, Marie-Pierre; Spezia, Riccardo; Vuilleumier, Rodolphe; Wien, Frank; Fujii, Kentaro; Yokoya, Akinari; Shikazono, Naoya

    2014-01-01

    We describe the progresses and current status of the REIMEI study on 'Initial processes of radiation effects on genomic stability', which is a new collaborative project between France and Japan. The theoretical study on the fragmentation pattern of doubly ionized deoxyribose has reached a new stage focusing on the effect of water molecules surrounding the deoxyribose molecule. In order to substantiate the theoretical predictions, new devices have been installed in a SPring-8 beamline. To explore the origin of signal transduction of DNA repair processes, a preliminary CD measurement in the far UV region was performed to study histone conformation changes. Based on these results, we will propose a new experimental subject in SOLEIL synchrotron to investigate the conformational changes of phosphorylated histone. Preliminary experiments using mammalian cell free extract have also been performed focusing on the role of DNA polymerases on the mutagenic potential of clustered DNA lesions. (author)

  11. Radiation-effects state of the art 1965-1966

    Energy Technology Data Exchange (ETDEWEB)

    Hamman, D.J.; Drennan, J.E.; Veazie, W.H.; Shober, F.R.; Leach, E.R.

    1966-06-30

    Developments in the field of radiation effects on electronic components including semiconductors, polymetric materials, lubricants, flotation fluids, hydraulic fluids, structural metals and alloys, ceramics, space radiation environment, dosimetry, and ceramic and metallic fuel materials are reviewed. Programs currently being conducted in radiation effects are briefly given for each section of the report.

  12. Radiation effects in wild terrestrial vertebrates - the EPIC collection.

    Science.gov (United States)

    Sazykina, Tatiana; Kryshev, Ivan I

    2006-01-01

    The paper presents data on radiation effects in populations of wild vertebrate animals inhabiting contaminated terrestrial ecosystems. The data were extracted from the database "Radiation effects on biota", compiled within the framework of the EC Project EPIC (2000-2003). The data collection, based on publications in Russian, demonstrates radiation effects in the areas characterized with high levels of radionuclides (Kyshtym radioactive trace; "spots" of enhanced natural radioactivity in the Komi region of Russia; territories contaminated from the Chernobyl fallout). The data covers a wide range of exposures from acute accidental irradiation to lifetime exposures at relatively low dose rates. Radiation effects include mortality, changes in reproduction, decrease of health, ecological effects, cytogenetic effects, adaptation to radiation, and others. Peculiarities of radiation effects caused by different radionuclides are described, also the severity of effects as they appear in different organisms (e.g. mice, frogs, birds, etc.).

  13. Radiation effects in wild terrestrial vertebrates - the EPIC collection

    International Nuclear Information System (INIS)

    Sazykina, Tatiana; Kryshev, Ivan I.

    2006-01-01

    The paper presents data on radiation effects in populations of wild vertebrate animals inhabiting contaminated terrestrial ecosystems. The data were extracted from the database 'Radiation effects on biota', compiled within the framework of the EC Project EPIC (2000-2003). The data collection, based on publications in Russian, demonstrates radiation effects in the areas characterized with high levels of radionuclides (Kyshtym radioactive trace; 'spots' of enhanced natural radioactivity in the Komi region of Russia; territories contaminated from the Chernobyl fallout). The data covers a wide range of exposures from acute accidental irradiation to lifetime exposures at relatively low dose rates. Radiation effects include mortality, changes in reproduction, decrease of health, ecological effects, cytogenetic effects, adaptation to radiation, and others. Peculiarities of radiation effects caused by different radionuclides are described, also the severity of effects as they appear in different organisms (e.g. mice, frogs, birds, etc.)

  14. Physics of intense, high energy radiation effects.

    Energy Technology Data Exchange (ETDEWEB)

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-02-01

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic

  15. Physics of intense, high energy radiation effects

    International Nuclear Information System (INIS)

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-01-01

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic calculations, the

  16. Metals and Ceramics Division Materials Science Program. Annual progress report for period ending December 31, 1982

    International Nuclear Information System (INIS)

    McHargue, C.J.

    1983-05-01

    This report summarizes the activities of the Materials Sciences Program in the Metals and Ceramics Division. These activities constitute about one-fourth of the research and development conducted by the division. The major elements of the Materials Sciences Program can be grouped under the areas of (1) structural characterization, (2) high-temperature alloy studies, (3) structural ceramics, and (4) radiation effects

  17. Radiation effects for high-energy protons and X-ray in integrated circuits

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, M.A.G.; Santos, R.B.B. [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil); Medina, N.H.; Added, N.; Tabacniks, M.H. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Lima, J.A. de [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Cirne, K.H. [Empresa Brasileira de Aeronautica S.A. (EMBRAER), Sao Jose dos Campos, SP (Brazil)

    2012-07-01

    Full text: Electronic circuits are strongly influenced by ionizing radiation. The necessity to develop integrated circuits (IC's) featuring radiation hardness is largely growing to meet the stringent environment in space electronics [1]. This work aims to development a test platform to qualify electronic devices under the influence of high radiation dose, for aerospace applications. To understand the physical phenomena responsible for changes in devices exposed to ionizing radiation several kinds of radiation should then be considered, among them heavy ions, alpha particles, protons, gamma and X-rays. Radiation effects on the ICs are usually divided into three categories: Total Ionizing Dose (TID), a cumulative dose that shifts the threshold voltage and increases transistor's off-state current; Single Events Effects (SEE), a transient effect which can deposit charge directly into the device and disturb the properties of electronic circuits and Displacement Damage (DD) which can change the arrangement of the atoms in the lattice [2]. In this study we are investigating the radiation effects in rectangular-gate and circular-gate MOSFETs, manufactured with standard CMOS fabrication process, using particle beams produced in electrostatic tandem accelerators and X-rays. Initial tests for TID effects were performed using the 1.7 MV 5SDH tandem Pelletron accelerator of the Instituto de Fisica da USP with a proton beam of 2.6 MeV. The devices were exposed to different doses, varying the beam current, and irradiation time with the accumulated dose reaching up to Grad. To study the effect of X-rays on the electronic devices, an XRD-7000 (Shimadzu) X-ray setup was used as a primary X-ray source. The devices were irradiated with a total dose from krad to Grad using different dose rates. The results indicate that changes of the I-V characteristic curve are strongly dependents on the geometry of the devices. [1] Duzellier, S., Aerospace Science and Technology 9, p. 93

  18. The Influence of Disciplines on the Knowledge of Science: A Study of the Nature of Science

    Directory of Open Access Journals (Sweden)

    B. Akarsu

    2010-06-01

    Full Text Available At least four factors affect pupils’ understanding of the nature of science: teachers’ specialization in different science areas (physics, chemistry, and biology, gender issues, teaching experience in elementary school environments, and the perspectives of acquiring necessary knowledge. This study is the introduction part of a research project which will be initiated soon. Four elementary science teachers participated in the study. The results reveal that participants’ views of the aspects of nature of science are not solely diverged, based on their major disciplines, but there exist significant distinctions according to gender differences.

  19. Using ISCCP Weather States to Decompose Cloud Radiative Effects

    Science.gov (United States)

    Oreopoulos, L.; Rossow, W. B.

    2012-01-01

    The presentation will examine the shortwave (SW) and longwave (LW) cloud radiative effect CRE (aka "cloud radiative forcing") at the top-of-the-atmosphere and surface of ISCCP weather states (aka "cloud regimes") in three distinct geographical zones, one tropical and two mid-latitude. Our goal is to understand and quantify the contribution of the different cloud regimes to the planetary radiation budget. In the tropics we find that the three most convectively active states are the ones with largest SW, LW and net TOA CRE contributions to the overall daytime tropical CRE budget. They account for 59%, 71% and 55% of the total CRE, respectively. The boundary layer-dominated weather states account for only 34% of the total SW CRE and 41% of the total net CRE, so to focus only on them in cloud feedback studies may be imprudent. We also find that in both the northern and southern midlatitude zones only two weather states, the first and third most convectively active with large amounts of nimbostratus-type clouds, contribute ",40% to both the SW and net TOA CRE budgets, highlighting the fact that cloud regimes associated with frontal systems are not only important for weather (precipitation) but also for climate (radiation budget). While all cloud regimes in all geographical zones have a slightly larger SFC than TOA SW CRE, implying cooling of the surface and slight warming of the atmosphere, their LW radiative effects are more subtle: in the tropics the weather states with plentiful high clouds warm the atmosphere while those with copious amounts of low clouds cool the atmosphere. In both midlatitude zones only the weather states with peak cloud fractions at levels above 440 mbar warm the atmosphere while all the rest cool it. These results make the connection of the contrasting CRE effects to the atmospheric dynamics more explicit - "storms" tend to warm the atmosphere whereas fair weather clouds cool it, suggesting a positive feedback of clouds on weather systems. The

  20. Radiation effect of gate controlled lateral PNP BJTs

    International Nuclear Information System (INIS)

    Xi Shanbin; Zhou Dong; Lu Wu; Ren Diyuan; Wen Lin; Sun Jing; Wang Zhikuan

    2012-01-01

    Design and fabricate a new test structure of bipolar device: the gate controlled later PNP bipolar transistor (GCLPNP BJT), then sealed it together with the normal lateral PNP bipolar transistor which is made under the same manufacture process. Then 60 Co-γ radiation effects and annealing behaviors of these two structures are investigated. The results show that the response about base current, collector current, access base current and normalized current gain of GCLPNP bipolar transistor are almost identical to the normal one. Radiation induced defects in the GCLPNP bipolar transistor is separated quantitatively. Studying on the quantitative change of radiation induced defects in the domestic gate controlled bipolar transistor should be a useful way to research the change of radiation induced charges of normal PNP bipolar transistor. (authors)

  1. Oxidation-reduction enzymes of myocardium under ionizing radiation effect

    International Nuclear Information System (INIS)

    Uteshev, A.B.

    1988-01-01

    Tissue respiration proceses under radiation effect were investigated which allowed one to reveal slight biochemical disturbances in a cell which make up the base of functional changes of different organs and tissues and to get to know the essence of tissue respiration processes. An attempt to explain significant value of oxidation enzyme system radiosensitivity in the course of cell respiration process altogether is made when studying the state of separate links of oxidation-reduction chain. It is shown that at early periods of radiation injury activity of catalase, dehydrogenases (isocitric, α-ketoglutaric, malic, succinic acids) is suppressed, concentration of a number of cytochromes is reduced and general ferrum content is increased which is connected with conformation changes of ultrastructure of mitochondrial membranes

  2. Microstructural characterization of radiation effects in nuclear materials

    CERN Document Server

    2017-01-01

    Microstructural Characterization of Radiation Effects in Nuclear Materials provides an overview into experimental techniques that can be used to examine those effects (both neutron and charged particle) and can be used by researchers, technicians or students as a tool to introduce them to the various techniques. The need to examine the effect of radiation on materials is becoming increasingly important as nuclear energy is emerging as a growing source of renewable energy. The book opens with a discussion of why it is important to study the effects of radiation on materials and looks at current and future reactor designs and the various constraints faced by materials as a result of those designs. The book also includes an overview of the radiation damage mechanisms. The next section explores the various methods for characterizing damage including transmission electron microscopy, scanning transmission electron microscopy, analytical electron microscopy, electron backscatter diffraction, atom probe tomography,...

  3. Experimental research on transient ionizing radiation effects of CMOS microcontroller

    International Nuclear Information System (INIS)

    Jin Xiaoming; Fan Ruyu; Chen Wei; Wang Guizhen; Lin Dongsheng; Yang Shanchao; Bai Xiaoyan

    2010-01-01

    This paper presents an experimental test system of CMOS microcontroller EE80C196KC20. Based on this system, the transient ionizing radiation effects on microcontroller were investigated using 'Qiangguang-I' accelerator. The gamma pulse width was 20 ns and the dose rate (for the Si atom) was in the range of 6.7 x 10 6 to 2.0 x 10 8 Gy/s in the experimental study. The disturbance and latchup effects were observed at different dose rate levels. Latchup threshold of the microcontroller was obtained. Disturbance interval and the system power supply current have a relationship with the dose rate level. The transient ionizing radiation induces photocurrent in the PN junctions that are inherent in CMOS circuits. The photocurrent is responsible for the electrical and functional degradation. (authors)

  4. Shortwave radiative effects of unactivated aerosol particles in clouds

    International Nuclear Information System (INIS)

    Ackerman, T.; Baker, M.B.

    1977-01-01

    Clouds in some polluted areas may contain high concentrations of anthropogenic aerosol particles. The possible role of these particles in perturbing the optical and dynamical properties of the clouds is an important question for climate studies. The direct radiative effects of unactivated aerosol particles in stable stratus clouds have been calculated at lambda=0.5μm. Several simplifying asumptions have been made relating the behavior of such particles in the high humidity enviornment within the cloud to their physicochemical make-up. It is shown that the energy absorbed by particles within the clouds may be, for realistic concentrations, comparable to the latent heat released and thus may play a significant role in cloud dynamics in some areas. These results are shown to be relatively insensitive to the assumptions about the particle properties within the cloud

  5. Radiation effects on epoxy composites at cryogenic temperatures

    International Nuclear Information System (INIS)

    Yamaoka, H.; Miyata, K.; Nishijima, S.; Okada, T.

    1995-01-01

    Radiation effects on glass-fiber reinforced epoxy composites at cryogenic temperatures has been studied by measuring the changes in interlaminar shear strength of the specimens. The scanning electron microscope observation has also been performed on fracture surface of the specimens. At 8.5 MGy of absorbed dose, only 10 % decrease of the strength was observed in the case of gamma irradiation, whereas over 80 % decrease of the strength was found on the reactor irradiated specimen. The difference of degradation behavior between gamma and reactor irradiations is attributed to the additional absorbed dose in the latter from the nuclear reaction due to boron-10 contained in the glass fibers by capture of thermal neutrons. (author)

  6. Case study of science teaching in an elementary school: Characteristics of an exemplary science teacher

    Science.gov (United States)

    Kao, Huey-Lien

    Improving the quality of science teaching is one of the greatest concerns in recent science education reform efforts. Many science educators suggest that case studies of exemplary science teachers may provide guidance for these reform efforts. For this reason, the characteristics of exemplary science teaching practices have been identified in recent years. However, the literature lacks research exploring exemplary teacher beliefs about the nature of science and science pedagogy, the relationships between their beliefs and practices, or how outstanding teachers overcome difficulties in order to facilitate their students' science learning. In this study, Sam-Yu, an identified exemplary science teacher who teaches in an elementary school in Pintung, Taiwan, was the subject. An interpretative research design (Erickson, 1986) based on principles of naturalistic inquiry (Lincoln & Guba, 1985) was used. Both qualitative and quantitative methods were employed in this case study. The qualitative method involved conducting interviews with the teacher and students, observing classroom activities and analyzing the structure of the learning materials. The quantitative methods involved using the Learning Climate Inventory (LCI) (Lin, 1997) instrument to assess the learning environment of the exemplary science classroom. This study found that Sam-Yu had a blend of views on the nature of science and a varied knowledge about science pedagogy. Personal preferences, past experiences, and the national science curriculum all played important roles in the development and refinement of Sam-Yu's beliefs about science and pedagogy. Regarding his teaching practices, Sam-Yu provided the best learning experiences, as evidenced in both classroom observations and the survey results, for his students by using a variety of strategies. In addition, his classroom behaviors were highly associated with his beliefs about science and pedagogy. However, due to school-based and socio-cultural constraints

  7. Environment, Science and Innovation. Analysis from the Perspective of Science Studies

    International Nuclear Information System (INIS)

    Muñoz, A.; Lopera, E.; Cornejo, M.

    2015-01-01

    )Humankind is facing important challenges. Environmental degradation, of which climate change is the main exponent, is one of them. Science and innovation are key factors to address this challenge, in a context in which is becoming more evident the lack of commitment of society with scientific and technological development. Taking this into consideration, this paper analyzes the interaction among environment, science and innovation from the perspective of science studies.

  8. Perspectives and opportunities for research in radiation effects on materials in the 1990's

    International Nuclear Information System (INIS)

    Mansur, L.K.

    1992-01-01

    Needs for research in radiation effects on materials span a broad range, from investigations of fundamental mechanisms to requirements on irradiation parameters suitable for technological studies in no less than a dozen reactor systems and subsystems. In the 1970's, 1980's and again in 1990, workshops were convened to refocus attention on progress and needs in these areas. Critical review papers and smaller meetings have also considered more specialized questions and identified important needs. In the present report, one author's view of current status and desirable avenues for radiation effects research are presented. Issues are discussed covering point defect production and availability, considerations peculiar to widely different classes of materials and radiation effects phenomena, and irradiation conditions needed for current and planned reactor systems. Research recommendations cannot be made independently of the availability of experimental facilities. Needs in the latter area are reflected in the paper

  9. Girls Doing Science: A Case Study of Science Literacy in All-Female Middle Grade Classrooms

    Science.gov (United States)

    Faller, Susan Elisabeth

    In the face of low adolescent literacy rates (NCES, 2012), concerns about the nation's prospects of remaining competitive in science and technology (Hill, Corbett, & St. Rose, 2010), a persistent gender gap in science (NCES, 2012; Reilly, 2012), and the continued rollout of college- and career-ready standards, there is a need to focus on adolescent girls' science literacy. Such science literacy involves not only general knowledge about science, but also the ability to engage in the advanced reading and writing practices fundamental to doing science (Norris & Phillips, 2003). In this thesis, I present three articles with findings that respond to this need. They are the results of a multiple-case embedded (Yin, 2009) study that I conducted over the course of 7 months in four science classrooms (grades 5 through 8; 50 students) taught by a single teacher in a small all-female middle school. I collected in-depth data focused on science literacy from multiple sources, including (a) fieldnotes (Emerson, Fretz & Shaw, 2011), (b) videorecorded classroom observations (102 classes, 113 hours, recorded on 29 days), (c) a survey of all students, (d) semi-structured interviews with the subsample of 12 focal students (ranging from 18 to 37 minutes) and (e) photographs of classroom artifacts and student work. In the first article, I provide a window into standard literacy practices in science classrooms by examining the reading and writing genres to which students are exposed. In the second article, I examine how a teacher's language and instructional practices within her classrooms, and popular images of science from the world beyond their classrooms might shape adolescent girls' science identities. Finally, in the third article, I explore different aspects of science identity using the words of three case study students. Taken together, these studies fill gaps in the literature by investigating science literacy in an understudied context, all-female classrooms. In addition

  10. Aerosol microphysical and radiative effects on continental cloud ensembles

    Science.gov (United States)

    Wang, Yuan; Vogel, Jonathan M.; Lin, Yun; Pan, Bowen; Hu, Jiaxi; Liu, Yangang; Dong, Xiquan; Jiang, Jonathan H.; Yung, Yuk L.; Zhang, Renyi

    2018-02-01

    Aerosol-cloud-radiation interactions represent one of the largest uncertainties in the current climate assessment. Much of the complexity arises from the non-monotonic responses of clouds, precipitation and radiative fluxes to aerosol perturbations under various meteorological conditions. In this study, an aerosol-aware WRF model is used to investigate the microphysical and radiative effects of aerosols in three weather systems during the March 2000 Cloud Intensive Observational Period campaign at the US Southern Great Plains. Three simulated cloud ensembles include a low-pressure deep convective cloud system, a collection of less-precipitating stratus and shallow cumulus, and a cold frontal passage. The WRF simulations are evaluated by several ground-based measurements. The microphysical properties of cloud hydrometeors, such as their mass and number concentrations, generally show monotonic trends as a function of cloud condensation nuclei concentrations. Aerosol radiative effects do not influence the trends of cloud microphysics, except for the stratus and shallow cumulus cases where aerosol semi-direct effects are identified. The precipitation changes by aerosols vary with the cloud types and their evolving stages, with a prominent aerosol invigoration effect and associated enhanced precipitation from the convective sources. The simulated aerosol direct effect suppresses precipitation in all three cases but does not overturn the aerosol indirect effect. Cloud fraction exhibits much smaller sensitivity (typically less than 2%) to aerosol perturbations, and the responses vary with aerosol concentrations and cloud regimes. The surface shortwave radiation shows a monotonic decrease by increasing aerosols, while the magnitude of the decrease depends on the cloud type.

  11. A fruitful encounter between Cognitive Science and Science & Technology Studies

    Directory of Open Access Journals (Sweden)

    Aleksandra Derra

    2013-06-01

    Full Text Available Scholars deriving from different schools of thought, especially if these grow out of different traditions, do not meet too frequently, and it is even more rare for these meeting to result in creating theories or research practices that would be cognitively surprising or rich in refreshing ideas. Therefore, the material we present in the current issue of Avant (1/2013 is exceptional. In the following part you can read articles by representatives of the so-called Toruń (postconstructivist school, “(Postconstructivism on the subject of techno-science” by Ewa Bińczyk and “A-socio-logy of a condition. A study of controversies surrounding etiology, diagnosis and therapy of ADHD” by Łukasz Afeltowicz and Michał Wróblewski.

  12. Climate change studies and the human sciences

    Science.gov (United States)

    Holm, Poul; Winiwarter, Verena

    2017-09-01

    Policy makers have made repeated calls for integration of human and natural sciences in the field of climate change. Serious multidisciplinary attempts began already in the 1950s. Progress has certainly been made in understanding the role of humans in the planetary system. New perspectives have clarified policy advice, and three insights are singled out in the paper: the critique of historicism, the distinction between benign and wicked problems, and the cultural critique of the 'myths of nature'. Nevertheless, analysis of the IPCC Assessment Reports indicates that integration is skewed towards a particular dimension of human sciences (economics) and major insights from cultural theory and historical analysis have not made it into climate science. A number of relevant disciplines are almost absent in the composition of authorship. Nevertheless, selective assumptions and arguments are made about e.g. historical findings in key documents. In conclusion, we suggest to seek remedies for the lack of historical scholarship in the IPCC reports. More effort at science-policy exchange is needed, and an Integrated Platform to channel humanities and social science expertise for climate change research might be one promising way.

  13. Radiative effects of interannually varying vs. interannually invariant aerosol emissions from fires

    Directory of Open Access Journals (Sweden)

    B. S. Grandey

    2016-11-01

    Full Text Available Open-burning fires play an important role in the earth's climate system. In addition to contributing a substantial fraction of global emissions of carbon dioxide, they are a major source of atmospheric aerosols containing organic carbon, black carbon, and sulfate. These “fire aerosols” can influence the climate via direct and indirect radiative effects. In this study, we investigate these radiative effects and the hydrological fast response using the Community Atmosphere Model version 5 (CAM5. Emissions of fire aerosols exert a global mean net radiative effect of −1.0 W m−2, dominated by the cloud shortwave response to organic carbon aerosol. The net radiative effect is particularly strong over boreal regions. Conventionally, many climate modelling studies have used an interannually invariant monthly climatology of emissions of fire aerosols. However, by comparing simulations using interannually varying emissions vs. interannually invariant emissions, we find that ignoring the interannual variability of the emissions can lead to systematic overestimation of the strength of the net radiative effect of the fire aerosols. Globally, the overestimation is +23 % (−0.2 W m−2. Regionally, the overestimation can be substantially larger. For example, over Australia and New Zealand the overestimation is +58 % (−1.2 W m−2, while over Boreal Asia the overestimation is +43 % (−1.9 W m−2. The systematic overestimation of the net radiative effect of the fire aerosols is likely due to the non-linear influence of aerosols on clouds. However, ignoring interannual variability in the emissions does not appear to significantly impact the hydrological fast response. In order to improve understanding of the climate system, we need to take into account the interannual variability of aerosol emissions.

  14. Investigation of the factors disguising radiation effects on the human body

    International Nuclear Information System (INIS)

    Korzeneva, I.B.; Styazhkina, T.V.; Dubrova, Y.E.; Malinina, T.V.; Prokhorovskaya, V.D.; Kholod, O.N.

    1998-01-01

    Herein we have studied the effects of some hereditary and environmental factors on children's states of health. The factors under investigation, along with radiation, also impact the immunological status and human adaptivity, thus disguising hazardous radiation effects. The state-of-health criterion we have chosen are children's liability to a wide range of intrinsic diseases through the first three years of life. The analysis involved 626 children (326 male and 300 female) who's parents and grandparents lived in the vicinity of the Russian Federal Nuclear Centre (RFNC), a large-scale nuclear facility. Our results should preferably be taken into consideration when projecting radiation effects on the human body. (author)

  15. Radiation effects of energetic thorium ions in monocrystalline Mg O and Si O2

    International Nuclear Information System (INIS)

    Abuassy, M.K.

    1995-01-01

    Radiation effects of energetic thorium ions in the energy range ∼ (100-1200) eV in both Mg O and Si O 2 single crystal have been investigated with program MARLOWE which simulate the collision cascades using the binary collision approximation. The effect of binding parameters on the radiation effects have been studied. The calculations covered the range, energy loss and Frenkel pair production. The results of MARLOWE have been compared with results of program TRIM and with the energy-partition theory of lindhard

  16. Modification of carcinogenic and antitumor radiation effects (biomedical aspects)

    International Nuclear Information System (INIS)

    Vilenchik, M.M.

    1985-01-01

    In the book the data on modification of carcinogenic radiation effects by physiologicaly active compounds (caffeine, hormones, promoters and others) as well as on potentiation of antitumor radiation effects by means of hyperthermia are systematized. It is shown that as a basis of synergetic (superadditive) carcinogenic or antitumor radiation effects combined with other factor can be the inhibiting effects of the latter on the reparation process of radiation-induced DNA injuries. The results of experimental investigations and the data on quantitative analysis can be used as a theoretical basis for improvement of the ways and means of the prophylaxis of tumor diseases as well as for increasing the efficiency of radiotherapy

  17. Study Skills of Arts and Science College Students

    Science.gov (United States)

    Sekar, J. Master Arul; Rajendran, K. K.

    2015-01-01

    The main objective of this study is to find out the level of study skills of arts and science college students. Study Skills Check List developed and standardized by Virginia University, Australia (2006) is used to collect the relevant data. The sample consists of 216 Government arts and science college students of Tiruchirappalli district, Tamil…

  18. An Empirical Study about China: Gender Equity in Science Education.

    Science.gov (United States)

    Wang, Jianjun; Staver, John R.

    A data base representing a random sample of more than 10,000 grade 9 students in an SISS (Second IEA Science Study) Extended Study (SES), a key project supported by the China State Commission of Education in the late 1980s, was employed in this study to investigate gender equity in student science achievement in China. This empirical data analysis…

  19. Scientists' attitudes on science and values: Case studies and survey methods in philosophy of science.

    Science.gov (United States)

    Steel, Daniel; Gonnerman, Chad; O'Rourke, Michael

    2017-06-01

    This article examines the relevance of survey data of scientists' attitudes about science and values to case studies in philosophy of science. We describe two methodological challenges confronting such case studies: 1) small samples, and 2) potential for bias in selection, emphasis, and interpretation. Examples are given to illustrate that these challenges can arise for case studies in the science and values literature. We propose that these challenges can be mitigated through an approach in which case studies and survey methods are viewed as complementary, and use data from the Toolbox Dialogue Initiative to illustrate this claim. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. New Approaches to the Study of Students' Response to Science

    DEFF Research Database (Denmark)

    Krogh, Lars

    2011-01-01

    of science and school science. In this chapter I describe two new approaches to the study of students’ responses to school science, both pragmatic by nature, and combining perspectives from cultural research with a quantitative or a Mixed Methods methodology. The approaches have been applied to studies......’Students’ responses’ to science include their attitudes and internalization of science (e.g. valueing, identifying) as well as their choices and actions related to science. This broader conception has advantages over attitudes alone, when it comes to understanding students’ paths in and out...... of Physics in Danish upper secondary school, and though these targeted different aspects of students’ responses and applied highly different methods the results were found to complement each other. A study using the first approach related students’ attitudes towards physics to various types of Cultural...

  1. Interpretive Media Study and Interpretive Social Science.

    Science.gov (United States)

    Carragee, Kevin M.

    1990-01-01

    Defines the major theoretical influences on interpretive approaches in mass communication, examines the central concepts of these perspectives, and provides a critique of these approaches. States that the adoption of interpretive approaches in mass communication has ignored varied critiques of interpretive social science. Suggests that critical…

  2. FCC study in Science Agora 2017

    CERN Multimedia

    Tomihisa, Kaoru

    2017-01-01

    Photos from European Union's participation in Science Agora 2017 in Tokyo. A number of events highlighted the strong collaborative efforts between Europe and Japan at frontier research. The global effort to design a Future Circular Collider was one of the projects presented as it highlights the international nature of modern research and how it transcends boundaries.

  3. Scientists Reflect on Why They Chose to Study Science

    Science.gov (United States)

    Venville, Grady; Rennie, Léonie; Hanbury, Colin; Longnecker, Nancy

    2013-12-01

    A concern commonly raised in literature and in media relates to the declining proportions of students who enter and remain in the `science pipeline', and whether many countries, including Australia and New Zealand, have enough budding scientists to fill research and industry positions in the coming years. In addition, there is concern that insufficient numbers of students continue in science to ensure an informed, scientifically literate citizenry. The aim of the research presented in this paper was to survey current Australian and New Zealand scientists to explore their reasons for choosing to study science. An online survey was conducted via a link to SurveyGizmo. The data presented are from 726 respondents who answered 22 forced-choice items and an open-ended question about the reasons they chose to study science. The quantitative data were analysed using t tests and analyses of variance followed by Duncan's multiple range tests, and the qualitative data were analysed thematically. The quantitative data showed that the main reasons scientists reported choosing to study science were because they were interested in science and because they were good at science. Secondary school science classes and one particular science teacher also were found to be important factors. Of much less importance were the prestige of science and financial considerations. The qualitative data expanded on these findings and showed that passion for science and/or curiosity about the world were important factors and also highlighted the importance of recreational pursuits, such as camping when a child. In the words of one respondent, `People don't go into science for the money and glory. It's passion for knowledge and science that always attracted me to the field'.

  4. Third International Mathematics and Science Study 1999 Video Study Technical Report: Volume 2--Science. Technical Report. NCES 2011-049

    Science.gov (United States)

    Garnier, Helen E.; Lemmens, Meike; Druker, Stephen L.; Roth, Kathleen J.

    2011-01-01

    This second volume of the Third International Mathematics and Science Study (TIMSS) 1999 Video Study Technical Report focuses on every aspect of the planning, implementation, processing, analysis, and reporting of the science components of the TIMSS 1999 Video Study. The report is intended to serve as a record of the actions and documentation of…

  5. Fusion-relevant basic radiation effects: theory and experiment

    International Nuclear Information System (INIS)

    Mansur, L.K.; Coghlan, W.A.; Farrell, K.; Horton, L.L.; Lee, E.H.; Lewis, M.B.; Packan, N.H.

    1983-01-01

    A summary is given of results of the basic radiation effects program at Oak Ridge National Laboratory, which are relevant to fusion reactor materials applications. The basic radiation effects program at ORNL is a large effort with the dual objectives of understanding the atomic and microstructural defect mechanisms underlying radiation effects and of determining principles for the design of radiation resistant materials. A strength of this effort is the parallel and integrated experimental and theoretical approaches in each major research area. The experimental effort is active in electron microscopy, ion irradiations and ion-beam techniques, neutron irradiations, surface analysis and in other areas. The theoretical effort is active in developing the theory of radiation effects for a broad range of phenomena and in applying it to the design and interpretation of experiments and to alloy design

  6. Radiation effects after low dose chronic long-term exposure

    International Nuclear Information System (INIS)

    Fliedner, T.M.; Friesecke, I.

    1997-01-01

    This document approaches the radiation effects after low dose chronic long-term exposure, presenting examples occurred, the pathophysiologic mechanisms for cell system tolerance in elevated radiation fields, and the diagnostic and therapeutic possibilities

  7. History, Philosophy and Sociology of Science in Science Education: Results from the Third International Mathematics and Science Study

    Science.gov (United States)

    Wang, Hsingchi A.; Sshmidt, William H.

    Throughout the history of enhancing the public scientific literacy, researchers have postulated that since every citizen is expected to have informal opinions on the relationships among government, education, and issues of scientific research and development, it is imperative that appreciation of the past complexities of science and society and the nature of scientific knowledge be a part of the education of both scientists and non-scientists. HPSS inclusion has been found to be an effective way to reach the goal of enhancing science literacy for all citizens. Although reports stated that HPSS inclusion is not a new educational practice in other part of the world, nevertheless, no large scale study has ever been attempted to report the HPSS educational conditions around the world. This study utilizes the rich data collected by TIMSS to unveil the current conditions of HPSS in the science education of about forty TIMSS countries. Based on the analysis results, recommendations to science educators of the world are provided.

  8. Directory of Research in Social Studies/Social Sciences.

    Science.gov (United States)

    Barret, Anna R.; Carnett, George S.

    Described are current trends in the social and behavioral sciences intended to meet the needs of the educational community. The projects listed include studies in anthropology, sociology, political science, history, geography, foreign area studies, economics, international relations, and environmental education. Part I of the directory lists…

  9. Case Studies in Science Education, Booklet X: Vortex as Harbinger.

    Science.gov (United States)

    Hoke, Gordon

    This booklet is the eleventh of a series of 16 booklets that together describe and present findings for a study which involved field observations and a survey of science teaching and learning in American public schools during the school year 1976-77. The study was undertaken to provide the National Science Foundation with a portrayal of current…

  10. Life science students' attitudes, interest, and performance in introductory physics for life sciences: An exploratory study

    Science.gov (United States)

    Crouch, Catherine H.; Wisittanawat, Panchompoo; Cai, Ming; Renninger, K. Ann

    2018-06-01

    In response to national calls for improved physical sciences education for students pursuing careers in the life sciences and medicine, reformed introductory physics for life sciences (IPLS) courses are being developed. This exploratory study is among the first to assess the effect of an IPLS course on students' attitudes, interest, and performance. The IPLS course studied was the second semester of introductory physics, following a standard first semester course, allowing the outcomes of the same students in a standard course and in an IPLS course to be compared. In the IPLS course, each physics topic was introduced and elaborated in the context of a life science example, and developing students' skills in applying physics to life science situations was an explicitly stated course goal. Items from the Colorado Learning about Science Survey were used to assess change in students' attitudes toward and their interest in physics. Whereas the same students' attitudes declined during the standard first semester course, we found that students' attitudes toward physics hold steady or improve in the IPLS course. In particular, students with low initial interest in physics displayed greater increases in both attitudes and interest during the IPLS course than in the preceding standard course. We also find that in the IPLS course, students' interest in the life science examples is a better predictor of their performance than their pre-IPLS interest in physics. Our work suggests that the life science examples in the IPLS course can support the development of student interest in physics and positively influence their performance.

  11. Family science: An ethnographic case study of the ordinary science and literacy experiences of one family

    Science.gov (United States)

    McCarty, Glenda M.

    Despite the copious research available on science learning, little is known about ways in which the public engages in free-choice science learning and even fewer studies have focused on how families engage in science to learn about the world around them. The same was true about studies of literacy development in the home until the 1980s when researchers (e.g. Bissex, 1980; Heath, 1983; Taylor, 1983) began documenting the literacy happenings and practices of young children in natural settings. Findings from intensive emergent literacy research studies have challenged traditional approaches to the teaching and learning of literacy, especially drawing attention to the active role children take in their own learning. Drawing upon those early literacy studies, this research project uses ethnographic case study methods along with a naturalistic inquiry approach, to document the daily explorations of one science-oriented family. Over a three year span, I have followed my own family, in our natural setting, through our day-to-day experiences with science and literacy as we seek to mediate and understand the world around us. In doing so, I have explored the ways we have shared knowledge and constructed learning through science books and read alouds, self-initiated inquiry learning, and communication. Throughout the three year research period, I have collected data and documented my own young children's understanding of the nature of science by observing their engagement with world around them.

  12. Gamma-radiation effect on diamond and steel during their irradiation in WWER type reactors

    International Nuclear Information System (INIS)

    Nikolaenko, V.A.; Karpukhin, V.I.; Amaev, A.D.; Vikhrov, V.I.; Korolev, Yu.N.; Krasikov, E.A.

    1996-01-01

    A study is made into the influence of reactor gamma radiation on expansion of crystal lattice in diamond. The data obtained are compared to those on radiation embrittlement of reactor vessel steels. The necessity of taking into consideration gamma radiation effects on WWER reactor vessel radiation resistance during long-term operation is shown [ru

  13. Radiation effects and hardness of semiconductor electronic devices for nuclear industry

    International Nuclear Information System (INIS)

    Payat, R.; Friant, A.

    1988-01-01

    After a brief review of industrial and nuclear specificity and radiation effects in electronics components (semiconductors) the need for a specific test methodology of semiconductor devices is emphasized. Some studies appropriate for nuclear industry at D. LETI/DEIN/CEN-SACLAY are related [fr

  14. Gamma radiation effect on the anatomical structure of soybean (Glycine max. Merr)

    International Nuclear Information System (INIS)

    Bhikuningputra, W.

    1976-01-01

    Gamma radiation effects on soybean plant (Glycine max. Merr) have been studied by using radiation doses of 0, 20, 25, 30, and 35 Krad. Investigation is carried out after each treatment. It proves that each treatment causes different morphological changes on leaves, stems, roots, and fibres of the treated plants. (SMN)

  15. Direct Radiative Effect of Mineral Dust on the Middle East and North Africa Climate

    KAUST Repository

    Bangalath, Hamza Kunhu

    2016-01-01

    Dust-climate interaction over the Middle East and North Africa (MENA) has long been studied, as it is the "dustiest" region on earth. However, the quantitative and qualitative understanding of the role of dust direct radiative effect on MENA climate

  16. Gamma radiation effects on rice, substrate for Sitophilus oryzae (L.) rearing

    International Nuclear Information System (INIS)

    Wiendl, F.M.; Arthur, V.; Walder, J.M.M.; Domarco, R.E.

    1987-01-01

    The gamma radiation effects (800 Krad, 60 Co) on rice are studied. Degraded substances by the radiation and how this degradation affects the biology of Sitophilus oryzae (L.) are searched. The vitamins, proteins and stard of the rice are affected by the radiation. (M.A.C.) [pt

  17. Influence of field study on learning and attitudes toward science

    Science.gov (United States)

    Brackney, David L.

    In an effort to improve attitudes toward science and academic achievement among college students who are non-science majors, an informal science educational experience in the form of a natural science field study course was created. The purpose of this study was to investigate the impact of a field study experience on student science attitudes and achievement. Outcomes from the field study groups were compared to students who enrolled in a traditional lecture/lab course. Academic achievement was measured via pre and posttest measures of geologic knowledge. Attitudes toward science were measured with a Science Attitudes Survey that utilized Likert-scale type items in the instrument. To explore student impressions and reactions to participating in the field study experience, interviews were conducted with open-ended questions. Patterns of responses were identified to explore common themes. Field study participants were found to have significantly higher gains from pre to posttest scores compared with the gains made by students who participated in a formal Earth Science course. There was no significant difference found in overall attitudes toward science and technology as measured with this attitudes survey between students who participated in the two formats of courses over the last five years. However, comments shared by participants in the field study through interviews suggest that their attitudes toward science had in fact been affected in positive ways. Other patterns of responses indicate positive impacts made on students on a number of fronts including affective, cognitive, and social interactions. All students interviewed rated the field study experience as valuable educationally or extremely valuable educationally.

  18. Non-Determinism: An Abstract Concept in Computer Science Studies

    Science.gov (United States)

    Armoni, Michal; Gal-Ezer, Judith

    2007-01-01

    Non-determinism is one of the most important, yet abstract, recurring concepts of Computer Science. It plays an important role in Computer Science areas such as formal language theory, computability theory, distributed computing, and operating systems. We conducted a series of studies on the perception of non-determinism. In the current research,…

  19. Breathing Life into Engineering: A Lesson Study Life Science Lesson

    Science.gov (United States)

    Lawrence, Maria; Yang, Li-Ling; Briggs, May; Hession, Alicia; Koussa, Anita; Wagoner, Lisa

    2016-01-01

    A fifth grade life science lesson was implemented through a lesson study approach in two fifth grade classrooms. The research lesson was designed by a team of four elementary school teachers with the goal of emphasizing engineering practices consistent with the "Next Generation Science Standards" (NGSS) (Achieve Inc. 2013). The fifth…

  20. Developing "Butterfly Warriors": A Case Study of Science for Citizenship

    Science.gov (United States)

    Chen, Junjun; Cowie, Bronwen

    2013-01-01

    Given worldwide concern about a decline in student engagement in school science and an increasing call for science for citizenship in New Zealand Curriculum, this study focused on a butterfly unit that investigated how students in a year-4 primary classroom learnt about New Zealand butterflies through thinking, talking, and acting as citizen…

  1. Radiation Effects Research Foundation bibliography of published papers, 1987

    International Nuclear Information System (INIS)

    1988-08-01

    The report lists the titles and authors of the reports of studies made under the Radiation Effects Research Foundation. The list include 87 studies, which cover 'immunological diagnosis of lung cancer', 'electrophoretic variants of haptoglobin found in the children of atomic bomb survivors', 'rogue cells in the general human population', 'host variation of X-ray sensitivity among atomic bomb survivors with or without breast cancer', 'disorders in the endocrine gland and gonad of A-bomb survivors', 'incidence of vertebral compression fractures among atomic bomb survivors', 'measurement of the frequency of in vivo somatic mutation in atomic bomb survivors by T-cell cloning', 'mechanism of carcinogenesis in A-bomb survivors', 'effects of aging on blood pressure', 'expediting factors of blood sedimentation of heavily exposed survivors', 'record linkage between local cancer registry and tumor and tissue registries', 'reclassification of diagnosis and types of leukemia in atomic bomb survivors in Hiroshima', 'cytogenetic study in utero exposed individuals', 'estimation of indoor and outdoor A-bomb gamma-ray doses by thermoluminescence measurement', and many other studies. (N.K.) 87 refs

  2. Science Education at Riverside Middle School A Case Study

    Science.gov (United States)

    Smiley, Bettie Ann Pickens

    For more than thirty years the gender gap in science and related careers has been a key concern of researchers, teachers, professional organizations, and policy makers. Despite indicators of progress for women and girls on some measures of achievement, course enrollment patterns, and employment, fewer women than men pursue college degrees and careers in science, technology, engineering, and mathematics. According to the results of national assessments, the gender gap in science achievement begins to be evident in the middle school years. Gender and school science achievement involve a complex set of factors associated with schools and child/family systems that may include school leadership, institutional practices, curriculum content, teacher training programs, teacher expectations, student interests, parental involvement, and cultural values. This ethnographic case study was designed to explore the context for science education reform and the participation of middle school girls. The study analyzed and compared teaching strategies and female student engagement in sixth, seventh, and eighth grade science classrooms. The setting was a middle school situated in a district that was well-known for its achievement in reading, math, and technology. Findings from the study indicated that while classroom instruction was predominantly organized around traditional school science, the girls were more disciplined and outperformed the boys. The size of the classrooms, time to prepare for hands-on activities, and obtaining resources were identified as barriers to teaching science in ways that aligned with recent national science reform initiatives. Parents who participated in the study were very supportive of their daughters' academic progress and career goals. A few of the parents suggested that the school's science program include more hands-on activities; instruction designed for the advanced learner; and information related to future careers. Overall the teachers and

  3. Investigation of Inquiry-based Science Pedagogy among Middle Level Science Teachers: A Qualitative Study

    Science.gov (United States)

    Weiland, Sunny Minelli

    This study implemented a qualitative approach to examine the phenomenon of "inquiry-based science pedagogy or inquiry instruction" as it has been experienced by individuals. Data was collected through online open-ended surveys, focus groups, and teacher reported self-reflections to answer the research questions: 1) How do middle level science teachers conceptualize "inquiry-based instruction?" 2) What are preferred instructional strategies for implementation in middle level science classrooms? And 3) How do middle level science teachers perceive the connection between science instruction and student learning? The participants within this research study represent 33 percent of teachers in grades 5 through 9 within six school districts in northeastern Pennsylvania. Of the 12 consent forms originally obtained, 10 teachers completed all three phases of the data collection, including the online survey, participation in focus groups, and teacher self-reflection. 60 percent of the participants taught only science, and 40 percent taught all content areas. Of the ten participants, 50 percent were certified teachers of science and 50 percent were certified as teachers of elementary education. 70 percent of the research participants reflected having obtained a master's, with 60 percent of these degrees being received in areas of education, and 10 percent in the area of science. The research participants have a total of 85 collective years of experience as professional educators, with the average years of experience being 8.5 years. Analysis of data revealed three themes related to research question #1) How do middle-level science teachers conceptualize inquiry-based instruction? and sub-question #1) How do middle-level science teachers characterize effective instruction? The themes that capture the essence of teachers' formulation of inquiry-based instruction that emerged in this study were student centered, problem solving, and hands-on . Analysis of data revealed one theme

  4. Valeriu Bologa’s studies on the history of science

    Science.gov (United States)

    BÂRSU, CRISTIAN

    2016-01-01

    History of science is a vast and complex domain, comprising many sub-domains, such as: the history of medicine, history of chemistry, history of physics etc. Different specialists in these sub-domains, trying to reach the general and integrative understanding of the history of science, succeeded only after they acquired a rich scientific experience in their fields of activity. One of the scientists who had interesting papers on the history of science was Valeriu Bologa (1892–1971). He was the first Romanian professor of history of medicine. Our paper presents some milestones regarding his preoccupations on the history of science. The aim of our study is to prove that, although he was primarily a historian of medicine, he surpassed this framework, proving to be a skillful historian of science. The topics of his works on the history of science included: the value of the unity of science, the ethical aspects of science during centuries, the interferences between the history of science and the history of medicine etc. PMID:27547069

  5. Valeriu Bologa's studies on the history of science.

    Science.gov (United States)

    Bârsu, Cristian

    2016-01-01

    History of science is a vast and complex domain, comprising many sub-domains, such as: the history of medicine, history of chemistry, history of physics etc. Different specialists in these sub-domains, trying to reach the general and integrative understanding of the history of science, succeeded only after they acquired a rich scientific experience in their fields of activity. One of the scientists who had interesting papers on the history of science was Valeriu Bologa (1892-1971). He was the first Romanian professor of history of medicine. Our paper presents some milestones regarding his preoccupations on the history of science. The aim of our study is to prove that, although he was primarily a historian of medicine, he surpassed this framework, proving to be a skillful historian of science. The topics of his works on the history of science included: the value of the unity of science, the ethical aspects of science during centuries, the interferences between the history of science and the history of medicine etc.

  6. The Impact of Teachers and Their Science Teaching on Students' "Science Interest": A Four-Year Study

    Science.gov (United States)

    Logan, Marianne R.; Skamp, Keith R.

    2013-01-01

    There is a crisis in school science in Australia and this may be related to insufficient students developing an interest in science. This extended study looked at changes in 14 students' interest in science as they moved through junior secondary school into Year 10. Although the majority of these students still had an interest in science in Year…

  7. Studies in Mathematics, Volume 22. Studies in Computer Science.

    Science.gov (United States)

    Pollack, Seymour V., Ed.

    The nine articles in this collection were selected because they represent concerns central to computer science, emphasize topics of particular interest to mathematicians, and underscore the wide range of areas deeply and continually affected by computer science. The contents consist of: "Introduction" (S. V. Pollack), "The…

  8. Undergraduate female science-related career choices: A phenomenological study

    Science.gov (United States)

    Curry, Kathy S.

    This qualitative phenomenological study used a modified Groenewald's five steps method with semi-structured, recorded, and transcribed interviews to focus on the underrepresentation of females in science-related careers. The study explored the lived experiences of a purposive sample of 25 senior female college students attending a college in Macon, Georgia. Ten major themes emerged from the research study that included (a) journey to a science-related career; (b) realization of career interest; (c) family support (d) society's role; (e) professors' treatment of students; (f) lack of mentors and models; (g) gender and career success; (h) females and other disadvantages in science-related careers; (i) rewards of the journey; and (j) advice for the journey. The three minor themes identified were (a) decision-making; (b) career awareness; and (c) guidance. The key findings revealed that females pursuing a science degree or subsequent science-related career, shared their experience with other females interested in science as a career choice, dealt with barriers standing in the way of their personal goals, lack role models, and received little or no support from family and friends. The study findings may offer information to female college students interested in pursuing science-related careers and further foundational research on gender disparities in career choice.

  9. African Journal of Educational Studies in Mathematics and Sciences ...

    African Journals Online (AJOL)

    African Journal of Educational Studies in Mathematics and Sciences. ... on senior high school students' proficiency in solving linear equation word problems ... from parents and teachers' influence on students' mathematics-related self-beliefs ...

  10. African Journal of Educational Studies in Mathematics and Sciences ...

    African Journals Online (AJOL)

    African Journal of Educational Studies in Mathematics and Sciences. ... The level of detail varies; some disciplines produce manuscripts that comprise discrete .... Duplicate publication, sometimes called self-plagiarism, occurs when an author ...

  11. Life science students’ attitudes, interest, and performance in introductory physics for life sciences: An exploratory study

    Directory of Open Access Journals (Sweden)

    Catherine H. Crouch

    2018-03-01

    Full Text Available In response to national calls for improved physical sciences education for students pursuing careers in the life sciences and medicine, reformed introductory physics for life sciences (IPLS courses are being developed. This exploratory study is among the first to assess the effect of an IPLS course on students’ attitudes, interest, and performance. The IPLS course studied was the second semester of introductory physics, following a standard first semester course, allowing the outcomes of the same students in a standard course and in an IPLS course to be compared. In the IPLS course, each physics topic was introduced and elaborated in the context of a life science example, and developing students’ skills in applying physics to life science situations was an explicitly stated course goal. Items from the Colorado Learning about Science Survey were used to assess change in students’ attitudes toward and their interest in physics. Whereas the same students’ attitudes declined during the standard first semester course, we found that students’ attitudes toward physics hold steady or improve in the IPLS course. In particular, students with low initial interest in physics displayed greater increases in both attitudes and interest during the IPLS course than in the preceding standard course. We also find that in the IPLS course, students’ interest in the life science examples is a better predictor of their performance than their pre-IPLS interest in physics. Our work suggests that the life science examples in the IPLS course can support the development of student interest in physics and positively influence their performance.

  12. Pretreatment Predictors of Adverse Radiation Effects After Radiosurgery for Arteriovenous Malformation

    International Nuclear Information System (INIS)

    Hayhurst, Caroline; Monsalves, Eric; Prooijen, Monique van; Cusimano, Michael; Tsao, May; Menard, Cynthia; Kulkarni, Abhaya V.; Schwartz, Michael; Zadeh, Gelareh

    2012-01-01

    Purpose: To identify vascular and dosimetric predictors of symptomatic T2 signal change and adverse radiation effects after radiosurgery for arteriovenous malformation, in order to define and validate preexisting risk models. Methods and Materials: A total of 125 patients with arteriovenous malformations (AVM) were treated at our institution between 2005 and 2009. Eighty-five patients have at least 12 months of clinical and radiological follow-up. Any new-onset headaches, new or worsening seizures, or neurological deficit were considered adverse events. Follow-up magnetic resonance images were assessed for new onset T2 signal change and the volume calculated. Pretreatment characteristics and dosimetric variables were analyzed to identify predictors of adverse radiation effects. Results: There were 19 children and 66 adults in the study cohort, with a mean age of 34 (range 6–74). Twenty-three (27%) patients suffered adverse radiation effects (ARE), 9 patients with permanent neurological deficit (10.6%). Of these, 5 developed fixed visual field deficits. Target volume and 12 Gy volume were the most significant predictors of adverse radiation effects on univariate analysis (p 3 , above which the rate of ARE increased dramatically. Multivariate analysis target volume and the absence of prior hemorrhage are the only significant predictors of ARE. The volume of T2 signal change correlates to ARE, but only target volume is predictive of a higher volume of T2 signal change. Conclusions: Target volume and the absence of prior hemorrhage is the most accurate predictor of adverse radiation effects and complications after radiosurgery for AVMs. A high percentage of permanent visual field defects in this series suggest the optic radiation is a critical radiosensitive structure.

  13. Radiation effect of ethylene/vinyl alcohol copolymer

    International Nuclear Information System (INIS)

    Liu Meihua; Jilin Univ., Changchun; Deng Pengyang; Sun Jiazhen; Dong Lisong; Sun Guoen; Zhang Wanxi

    2006-01-01

    The radiation effect of ethylene-vinyl alcohol copolymer (EVOH), EVOH/glycerin blend was studied by solvent extraction, gel permeation chromatography (GPC) and Fourier transform infrared spectrum (FTIR) methods. Samples were irradiated up to 1800 kGy at room temperature under N 2 . The results show that degradation is the main reaction in pure EVOH. Trace gel content could be found in E151 irradiated to at least 800 kGy, and only 5.9% gel content was found in the sample irradiated to 1200 kGy. While trace gel content could be found in F101 irradiated to at least 1800 kGy, the different gelation doses of E151 and F101 are due to different contents of vinyl alcohol units. Unsaturation structure can be found in the irradiated EVOH. The content increased at first, and then decreased, with the dose. The existence of double bond enhances the radiation efficiency of EVOH. For EVOH/glycerin blend, the gel content was higher than that of pure EVOH when the absorbed dose exceeds 800 kGy, and the gel content increased with the absorbed dose. But it cannot enhance radiation efficiency of EVOH as water. (authors)

  14. The treatment of late radiation effects with hyperbaric oxygenation (HBO)

    International Nuclear Information System (INIS)

    Plafki, C.; Carl, U.M.; Glag, M.; Hartmann, K.A.

    1998-01-01

    Background: Late radiation injuries may impose a negative influence on the quality of life in the affected patients. In several entities, standardized treatment protocols are lacking. Hyperbaric oxygenation (HBO) has been shown to have beneficial effects in the treatment of late radiation sequelae. Material and methods: The basic principles of HBO are reviewed as well as clinical issues. Current study protocols are presented. Results: During HBO-therapy the patient breathes pure oxygen at pressures above 100 kPa. The oxygen solubility within the fluid phase of the blood is largely increased. Biological effects include an increased oxygen diffusibility, improved collagen synthesis and neoangiogenesis as well as an enhancement of antimicrobial defenses. By decreasing the capillary filtration pressure a reduction of edema becomes possible. HBO has been shown to prevent complications following surgery in irradiated tissues. Its efficacy as an adjunct in the treatment of osteonecroses in radiation patients could be demonstrated. In addition, the loss of osseointegrated implants in the maxillofacial bones of these patients could be significantly reduced. Further indications include soft tissue necroses, hemorrhagic cystitis and proctitis in tumor patients that have been treated by radiotherapy as part of a multimodality approach. Conclusions: HBO in the treatment of late radiation effects is still subject of investigation, but remarkable results have been reported. Optimized treatment protocols need to be determined in various entities. The rate of side effects is acceptable low. (orig.) [de

  15. Radiation effects on ion exchange materials used in waste management

    International Nuclear Information System (INIS)

    Pillay, K.K.S.

    1982-01-01

    Radiation damage to process materials used in radioactive waste management has been a topic of little interest in the past. In recent years, as a result of the increasing number of accidents reported in the open literature, there has been some desire to examine the radiation decomposition of ion exchange materials and its consequences to the interim and long-term management of radioactive wastes. Extensive literature surveys and some confirmatory laboratory investigations conducted conclusively demonstrate that radiation damage to ion exchangers has the potential to cause problems of corrosion, elution of adsorbed ionic species, generation of flammable and explosive gaseous products and agglomeration of particulates to form rigid monoliths. This paper is an overview of present knowledge and a presentation of the results of our investigations of this phenomenon. The distinct lack of systematic studies to evaluate the problems of radiation damage to process materials used in the consolidation and isolation of high specific activity radionuclides still leaves considerable gaps in our knowledge of the processes and consequences of radiation effects on ion exchangers used in radioactive waste management

  16. Radiation Effects Research Foundation bibliography of published papers, 1986

    International Nuclear Information System (INIS)

    1987-01-01

    The bibliography lists the titles of a total of 75 papers published by members of the Radiation Effects Research Foundation in 1986 (three of them published in 1985). The papers cover; 'The central nervous system and in utero exposure to ionizing radiation', 'Future directions for biostatistics and cancer epidemiology in Japan', 'Passive smoking and lung cancer among Japanese women', 'Late effects of atomic bomb radiation on human immune response', 'Delayed effects of atomic bomb radiation to human cellular immune competence', 'Characterization of three electrophoretic variants of human erythrocyte triosephosphate isomerase found in Japanese', 'A follow-up study of clonal T-lymphocytes with chromosome aberrations in Hiroshima A-bomb survivors', 'Comments on recent cytogenetic findings at RERF', 'Cytogenetic 'rogue' cells; What is their frequency, origin, and evolutionary sinificance?', 'A parallel analysis of cancer mortality among atomic bomb survivors and patients with ankylosing spondylitis given X-ray therapy', 'Cancer of the thyroid and salivary glands', 'Analysis of peripheral blood lymphocytes of atomic bomb survivors using monoclonal antibodies', 'Celluar immune competence of patients with lung cancer and other lung diseases. I. Analysis of peripheral blood lymphocyte subsets using monoclonal antibodies', etc. (N.K.) 75 refs

  17. The development and purpose of the FREDERICA radiation effects database

    International Nuclear Information System (INIS)

    Copplestone, D.; Hingston, J.; Real, A.

    2008-01-01

    Any system for assessing the impact of a contaminant on the environment requires an analysis of the possible effects on the organisms and ecosystems concerned. To facilitate this, the FREDERICA radiation effects database has been developed to provide an online search of the known effects of ionising radiation on non-human species, taken from papers in the scientific peer reviewed literature. The FREDERICA radiation effects database has been produced by merging the work done on radiation effects under two European funded projects (FASSET and EPIC) and making the database available online. This paper highlights applications for the database, gaps in the available data and explains the use of quality scores to help users of the database determine which papers may benefit their research in terms of techniques and reproducibility

  18. Terrestrial radiation effects in ULSI devices and electronic systems

    CERN Document Server

    Ibe, Eishi H

    2014-01-01

    A practical guide on how mathematical approaches can be used to analyze and control radiation effects in semiconductor devices within various environments Covers faults in ULSI devices to failures in electronic systems caused by a wide variety of radiation fields, including electrons, alpha -rays, muons, gamma rays, neutrons and heavy ions. Readers will learn the environmental radiation features at the ground or avionics altitude. Readers will also learn how to make numerical models from physical insight and what kind of mathematical approaches should be implemented to analyze the radiation effects. A wide variety of mitigation techniques against soft-errors are reviewed and discussed. The author shows how to model sophisticated radiation effects in condensed matter in order to quantify and control them. The book provides the reader with the knowledge on a wide variety of radiation fields and their effects on the electronic devices and systems. It explains how electronic systems including servers and rout...

  19. NSTX Diagnostics for Fusion Plasma Science Studies

    International Nuclear Information System (INIS)

    Kaita, R.; Johnson, D.; Roquemore, L.; Bitter, M.; Levinton, F.; Paoletti, F.; Stutman, D.

    2001-01-01

    This paper will discuss how plasma science issues are addressed by the diagnostics for the National Spherical Torus Experiment (NSTX), the newest large-scale machine in the magnetic confinement fusion (MCF) program. The development of new schemes for plasma confinement involves the interplay of experimental results and theoretical interpretations. A fundamental requirement, for example, is a determination of the equilibria for these configurations. For MCF, this is well established in the solutions of the Grad-Shafranov equation. While it is simple to state its basis in the balance between the kinetic and magnetic pressures, what they are as functions of space and time are often not easy to obtain. Quantities like the plasma pressure and current density are not directly measurable. They are derived from data that are themselves complex products of more basic parameters. The same difficulties apply to the understanding of plasma instabilities. Not only are the needs for spatial and temporal resolution more stringent, but the wave parameters which characterize the instabilities are difficult to resolve. We will show how solutions to the problems of diagnostic design on NSTX, and the physics insight the data analysis provides, benefits both NSTX and the broader scientific community

  20. Radiation effects on the developing human brain

    International Nuclear Information System (INIS)

    1993-01-01

    The developing human brain has been shown to be especially sensitive to ionizing radiation. Mental retardation has been observed in the survivors of the atomic bombings in Japan exposed in utero during sensitive periods, and clinical studies of pelvically irradiated pregnant women have demonstrated damaging effects on the fetus. In this annex the emphasis is on reviewing the results of the study of the survivors of the atomic bombings in Japan, although the results of other human epidemiological investigations and of pertinent experimental studies are also considered. Refs, 3 figs, 10 tabs

  1. Decomposition of radiational effects of model feedbacks

    International Nuclear Information System (INIS)

    Ellsaesser, H.W.; MacCracken, M.C.; Potter, G.L.; Mitchell, C.S.

    1981-08-01

    Three separate doubled CO 2 experiments with the statistical dynamic model are used to illustrate efforts to study the climate dynamics, feedbacks, and interrelationships of meteorological parameters by decomposing and isolating their individual effects on radiation transport

  2. Plasma Science Committee (PLSC) and study on new opportunities in plasma science and technology

    International Nuclear Information System (INIS)

    1992-01-01

    The Plasma Science Committee (PLSC) of the National Research Council (NRC) is charged with monitoring the health of the field of plasma science in the United States. Accordingly, the Committee identifies and examines both broad and specific issues affecting the field. Regular meetings, teleconferences, briefings from agencies and the scientific community, the formation of study panels to prepare reports, and special symposia are among the mechanisms used by the PLSC to meet its charge. This progress report presents a review of PLSC activities from July 15, 1991 to May 31, 1992. The details of prior activities are discussed in earlier reports. This report also includes the status of activities associated with the PLSC study on opportunities in plasma science and technology. During the above period, the PLSC has continued to track and participate in, when requested, discussions on the health of the field. Much of the perspective of the PLSC has been presented in the recently-published report Research Briefing on Contemporary Problems in Plasma Science. That report has served as the basis for briefings to representatives of the federal government as well as the community-at-large. In keeping with its charge to identify and highlight specific areas for scientific and technological opportunities, the PLSC completed publication of the report Plasma Processing of Materials: Scientific and Technological Opportunities and launched a study on new opportunities in plasma science and technology

  3. Exploring inductive risk case studies of values in science

    CERN Document Server

    Richards, Ted

    2017-01-01

    Science is the most reliable means available for understanding the world around us and our place in it. But, since science draws conclusions based on limited empirical evidence, there is always a chance that a scientific inference will be incorrect. That chance, known as inductive risk, is endemic to science. Though inductive risk has always been present in scientific practice, the role of values in responding to it has only recently gained extensive attention from philosophers, scientists, and policy-makers. Exploring Inductive Risk brings together a set of eleven concrete case studies with the goals of illustrating the pervasiveness of inductive risk, assisting scientists and policymakers in responding to it, and moving theoretical discussions of this phenomenon forward. The case studies range over a wide variety of scientific contexts, including the drug approval process, high energy particle physics, dual-use research, climate science, research on gender disparities in employment, clinical trials, and to...

  4. Coherent Synchrotron Radiation effect in damping rings

    International Nuclear Information System (INIS)

    Raubenheimer, T

    2004-01-01

    Coherent Synchrotron Radiation (CSR) can play an important role by not only increasing the energy spread and emittance of a beam, but also leading to a potential instability. Previous studies of the CSR induced longitudinal instability were carried out for the CSR impedance due to dipole magnets. In this paper, the instability due to the CSR impedance from a wiggler is studied assuming a large wiggler parameter K. The primary consideration is a low frequency microwave-like instability in the damping rings of several linear collider projects. The threshold is determined by the instability with the longest possible wavelength

  5. Photonuclear and Radiation Effects Testing with a Refurbished 20 MeV Medical Electron Linac

    CERN Document Server

    Webb, Timothy; Beezhold, Wendland; De Veaux, Linda C; Harmon, Frank; Petrisko, Jill E; Spaulding, Randy

    2005-01-01

    An S-band 20 MeV electron linear accelerator formerly used for medical applications has been recommissioned to provide a wide range of photonuclear activation studies as well as various radiation effects on biological and microelectronic systems. Four radiation effect applications involving the electron/photon beams are described. Photonuclear activation of a stable isotope of oxygen provides an active means of characterizing polymer degradation. Biological irradiations of microorganisms including bacteria were used to study total dose and dose rate effects on survivability and the adaptation of these organisms to repeated exposures. Microelectronic devices including bipolar junction transistors (BJTs) and diodes were irradiated to study photocurrent from these devices as a function of peak dose rate with comparisons to computer modeling results. In addition, the 20 MeV linac may easily be converted to a medium energy neutron source which has been used to study neutron damage effects on transistors.

  6. Science Mission Definition Studies for TROPIX

    Science.gov (United States)

    Fennell, J. F.

    1997-01-01

    This document summarizes the results of mission definition studies for solar electric propulsion missions that have been carried out over the last approximately three years. The major output from the studies has been two proposals which were submitted to NASA in response to Announcements of Opportunity for missions and an ongoing Global Magnetospheric Dynamics mission study. The bulk of this report consists of copies of the proposals and preliminary materials from the GMD study that will be completed in the coming months.

  7. A Case Study Investigating Secondary Science Teachers' Perceptions of Science Literacy Instruction

    Science.gov (United States)

    Blackmon, Phyllis Ann

    This project study addressed the lack of inclusion of discipline literacy pedagogy in secondary classrooms in a rural school district in eastern North Carolina. Discipline literacy practices are recommended in the Common Core Standards for History/Social Studies, Science, and Technical Subjects. The district had implemented content area reading strategies across content areas, yet no significant progress in secondary students' reading abilities had been demonstrated in statewide or national assessments. The conceptual framework that drove this study was disciplinary literacy, founded by the literacy research of Shanahan, Shanahan, and Zygouris-Coe. Within a qualitative case study method, this investigation of 8 secondary science teachers' experiences teaching literacy during content instruction focused on practices of embedding science-specific reading strategies into lessons and factors that influence teachers' decisions to participate in professional development to advance their learning of discipline-specific literacy methods. Data were collected and triangulated using a focus group and 8 individual interviews. Data from both methods were analyzed into codes and categories that developed into emergent themes. Findings from the focus group and individual interviews revealed that the science teachers possessed limited knowledge of science-specific reading strategies; used random, general literacy practices; and had completed inadequate professional development on science-related topics. Positive change may occur if district leaders support teachers in expanding their knowledge and application of discipline literacy strategies through participation in discipline literacy-focused professional development. The study may provide educators and researchers a deeper understanding of disciplinary literacy and increase research on the topic.

  8. Blinded with Science or Informed by Charts? A Replication Study

    OpenAIRE

    Dragicevic , Pierre; Jansen , Yvonne

    2018-01-01

    International audience; We provide a reappraisal of Tal and Wansink's study "Blinded with Science" , where seemingly trivial charts were shown to increase belief in drug efficacy, presumably because charts are associated with science. Through a series of four replications conducted on two crowdsourcing platforms, we investigate an alternative explanation, namely, that the charts allowed participants to better assess the drug's efficacy. Considered together, our experiments suggest that the ch...

  9. Activities and future plans of the radiation effects research foundation

    International Nuclear Information System (INIS)

    Nagataki, Shigenobu

    2000-01-01

    The Radiation Effects Research Foundation (RERF) was established in 1975 as a binational research foundation supported by Japan and the United States. It continues the work of the Atomic Bomb Casualty Commission (ABCC) which was established in 1974. ABCC-RERF studies focus on several fixed cohorts of survivors and their children: the Life Span Study (LSS) cohort (120,000 survivors); the In-Utero cohort (3,300 people born within 9 months of the bombings); the F 1 cohort (88,000 people born between mid-1946 and 1984), and the Adult Health Study (AHS) cohort (an ongoing clinical study of 17,000 LSS survivors and 1,100 people exposed in-utero). Epidemiological data have shown increased risks of leukemia and solid cancers by radiation exposure among the survivors. Excess leukemia risks, especially for children, were markedly elevated 5 to 10 years after exposure and have continued at reduced levels. Excess solid cancer rates became apparent within 10 years after exposure, increasing throughout life in rough proportion to background rates. For doses of interest in radiation protection excess leukemia risks exhibit an upward curving dose response pattern while the solid cancer excess appears to be linear by dose with no apparent threshold. In addition to malignancy, AHS data has shown dose-related increased risk for various non-malignant diseases; radiation cataracts, benign tumors of uterus, thyroid and parathyroid (hyperparathyroidism), and autoimmune thyroid diseases. Persons exposed in-utero exhibit a broad range of dose-related effects including delayed growth and development and higher rates of microcephaly. Studies of birth defects, chromosome aberrations, childhood mortality, and genetic variants of serum or erythrocyte proteins have provided no indication of heritable mutations in the F 1 cohort. Continued follow-up of survivors exposed as children (90% are still alive) is essential to understanding the temporal pattern of excess risks and lifetime risks, and may

  10. Secondary Science Teachers' Implementation of CCSS and NGSS Literacy Practices: A Survey Study

    Science.gov (United States)

    Drew, Sally Valentino; Thomas, Jeffrey

    2018-01-01

    Most middle and high school students struggle with reading and writing in science. This may be because science teachers are reluctant to teach literacy in science class. New standards now require a shift in the way science teachers develop students' literacy in science. This survey study examined the extent to which science teachers report…

  11. Radiation effect on PVC/ENR blends

    International Nuclear Information System (INIS)

    Chantara Thevy Ratnam; Khairul Zaman Mohd Dahlan

    1997-01-01

    The effect of irradiation on the physical properties of Polyvinyl Chloride / Epoxidised Natural Rubber Blends (PVC/ENR blends) were investigated. The enhancement in tensile strength, elongation at break, hardness and aging properties of the blends have confirmed the positive effect of irradiation on the blends. It is evident from gel fraction and infra red spectroscopic studies that the blends of PVC and ENR cross-linked upon irradiation. The results also revealed that at any blend composition, the enhancement in properties depend on irradiation dose which controls the degree of radiation induced cross-linking. In an attempt to maximize the constructive effect of irradiation, the influence of various additives such as stabilizers, radiation sensitizers, fillers and processing aids on the blend properties were studied. The changes in blend properties upon irradiation with the presents of above additives were also presented in this paper

  12. Radiation effects on the integrity of paper

    International Nuclear Information System (INIS)

    Otero D'Almeida, Maria Luiza; Medeiros Barbosa, Patricia de Souza; Boaratti, Marcelo Fernando Guerra; Borrely, Sueli Ivone

    2009-01-01

    Books and documents attacked by fungi and insects have already been treated by radiation for disinfestations purposes. However, there is still need to investigate the influence of radiation on the cellulose paper structure. The aim of this research was to study the effects of radiation on paper properties, especially those related to strength and appearance. Paper sheets for this study were prepared in the laboratory, using bleached eucalyptus pulp as raw material. No additives were used to concentrate the attention only on the effects of irradiation on the pure cellulose matrix. The samples were irradiated at IPEN's 60 Co Gammacell irradiator with six radiation doses, from 3 to 15 kGy at the dose rate 0.817 Gy/s. The properties of paper sheets were tested after irradiation and compared with unirradiated samples according to ISO methods. No significant changes were detected in paper samples irradiated up to 15 kGy.

  13. X-radiation effect on water transport in ascite cells of Ehrlich carcinoma

    International Nuclear Information System (INIS)

    Barnov, V.A.; Ajvazishvili, M.A.; Kartvelishvili, I.I.; Tushishvili, D.I.

    1988-01-01

    Effect of local X radiation with doses 0.05 and 0.15 C/kg on water transport in ascitic cells of Erlich carcinoma is studied in rats. To study water transport through cell membranes, tritium mark was used. It is concluded that radiation effect on water transport in cells of Erlich carcinoma may be related to change in ionic permittivity of the membrane, because small changes in transmembrane ion transport affect immediately the osmotic motion of water. 5 refs

  14. Hispanic women overcoming deterrents to computer science: A phenomenological study

    Science.gov (United States)

    Herling, Lourdes

    The products of computer science are important to all aspects of society and are tools in the solution of the world's problems. It is, therefore, troubling that the United States faces a shortage in qualified graduates in computer science. The number of women and minorities in computer science is significantly lower than the percentage of the U.S. population which they represent. The overall enrollment in computer science programs has continued to decline with the enrollment of women declining at a higher rate than that of men. This study addressed three aspects of underrepresentation about which there has been little previous research: addressing computing disciplines specifically rather than embedding them within the STEM disciplines, what attracts women and minorities to computer science, and addressing the issues of race/ethnicity and gender in conjunction rather than in isolation. Since women of underrepresented ethnicities are more severely underrepresented than women in general, it is important to consider whether race and ethnicity play a role in addition to gender as has been suggested by previous research. Therefore, this study examined what attracted Hispanic women to computer science specifically. The study determines whether being subjected to multiple marginalizations---female and Hispanic---played a role in the experiences of Hispanic women currently in computer science. The study found five emergent themes within the experiences of Hispanic women in computer science. Encouragement and role models strongly influenced not only the participants' choice to major in the field, but to persist as well. Most of the participants experienced a negative atmosphere and feelings of not fitting in while in college and industry. The interdisciplinary nature of computer science was the most common aspect that attracted the participants to computer science. The aptitudes participants commonly believed are needed for success in computer science are the Twenty

  15. Ionizing Radiation Effects in Ni Nanotubes

    Science.gov (United States)

    Shlimas, D.; Kozlovsky, A.; Shumskaya, A.; Kaniukov, E.; Ibragimova, M.; Zdorovets, M.; Kadyrzhanov, K.

    2017-01-01

    Polycrystalline nickel nanotubes with diameter of 380 nm and wall thickness 95 nm were synthesized by electrochemical method using PET track-etched membranes with thickness of 12 μm. A comprehensive study of the structural, morphological and electrical characteristics of Ni nanotubes irradiated with C+13 ions with energy 1.75 MeV/nucleon and fluence ranging from 109 to 5 × 1011 cm-2 was carried out. The ability of modification of structural parameters such as lattice parameter and the average size of crystallites and conductivity of Ni nanotubes by irradiation was shown.

  16. Gamma Radiation Effect on Titan Yellow Solutions

    International Nuclear Information System (INIS)

    El-Banna, M.

    2012-01-01

    In the present work, the radiation induced color bleaching of Titan yellow dye (TY) in different solvents has been studied. The color bleaching of the dye solutions upon irradiation was followed spectrophotometrically. The % color bleaching of the dyes in different solvent systems was plotted against different gamma irradiation doses used and was determined and the obtained relationships were found to be linear in most cases. These relationships were used as calibration curves to determine the unknown irradiation dose. The results obtained were reproducible and showed differences from calculated values ranging from 10 % to 15 %

  17. Temperature dependence of radiation effects in polyethylene

    International Nuclear Information System (INIS)

    Wu, G; Katsumura, Y.; Kudoh, H.; Morita, Y.; Seguchi, T.

    2000-01-01

    Temperature dependence of crosslinking and gas evolution under γ-irradiation was studied for high-density and low-density polyethylene samples in the 30-360degC range. It was found that crosslinking was the predominant process up to 300degC and the gel point decreased with increasing temperature. At above 300degC, however, the gel fraction at a given dose decreased rapidly with temperature and the action of radiation turned to enhance polyethylene degradation. Yields of H 2 and hydrocarbon gases increased with temperature and the compositions of hydrocarbons were dose dependent. (author)

  18. Ionizing radiation effects on silicon test structures

    International Nuclear Information System (INIS)

    Kraner, H.W.; Beuttenmuller, R.; Chen, W.; Kierstead, J.A.; Li, Z.; Zhang, Y.; Dou, L.; Fretwurst, E.; Lindstroem, G.

    1993-12-01

    The effects of 60 Co gamma irradiation on MOSCAPS and special junction diode detectors have been studied. The capacitors were used to ellicit the charge accumulation and anneal in two types of thermally grown oxides representative of those used in routine detector processing. Ion implanted, oxide passivated junction detectors having 0.25 and 1 cm 2 areas and perimeter to area ratios of 1 (a square), 2 and 5 were designed and constructed to amplify the ionizing effects expected to largely affect junction edges through changes in fixed oxide charges. Detectors were exposed to over 4 Mrad and showed clear increases in leakage current in proportion to the junction edge length. Annealing schedules were determined to provide a continuous response to incremental irradiations and subsequent room temperature anneals of leakage current. Besides an increase in gate threshold, little effect on the C(V) response was found. PISCES simulation of the edge fields using different fixed oxide charge revealed regions of very high lateral fields near the junction edges for fixed charges in the 2 x 10 12 /cm 2 range expected from the capacitor studies which could be responsible for the observed leakage currents

  19. Direct Radiative Effect of Mineral Dust on the Middle East and North Africa Climate

    KAUST Repository

    Bangalath, Hamza Kunhu

    2016-11-01

    Dust-climate interaction over the Middle East and North Africa (MENA) has long been studied, as it is the "dustiest" region on earth. However, the quantitative and qualitative understanding of the role of dust direct radiative effect on MENA climate is still rudimentary. The present dissertation investigates dust direct radiative effect on MENA climate during summer with a special emphasis on the sensitivity of climate response to dust shortwave absorption, which is one of the most uncertain components of dust direct radiative effect. Simulations are conducted with and without dust radiative effect, to differentiate the effect of dust on climate. To elucidate the sensitivity of climate response to dust shortwave absorption, simulations with dust assume three different cases of dust shortwave absorption, representing dust as a very efficient, standard and inefficient shortwave absorber. The non-uniformly distributed dust perturb circulations at various scales. Therefore, the present study takes advantage of the high spatial resolution capabilities of an Atmospheric General Circulation Model (AGCM), High Resolution Atmospheric Model (HiRAM), which incorporates global and regional circulations. AMIP-style global high-resolution simulations are conducted at a spatial resolution of 25 km. A significant response in the strength and position of the local Hadley circulation is predicted in response to meridionally asymmetric distribution of dust and the corresponding radiative effects. Significant responses are also found in regional circulation features such as African Easterly Jet and West African Monsoon circulation. Consistent with these dynamic responses at various scales, the tropical rainbelt across MENA strengthens and shifts northward. Similarly, the temperature under rainbelt cools and that over subtropical deserts warms. Inter-comparison of various dust shortwave absorption cases shows that the response of the MENA tropical rainbelt is extremely sensitive to the

  20. Indirect radiation effects related to the environmental structure of targets

    International Nuclear Information System (INIS)

    Frankenberg, D.

    1976-01-01

    It is supposed, that in biological systems there are direct as well as indirect radiation effects. Their contributions to lethal effects depend mainly on two different kinds of structures within irradiated systems: the microscopic energy deposition patterns of radiation and the environmental structures of targets. The approach to determine these contributions of the lethal action of ionizing radiation in yeast cells was, to use chemical compounds, which specifically change the radical spectrum of water radiolysis. The efficiency of such chemical compounds in scavenging specifically water radicals was tested in aqueous solutions of thymine molecules, in which indirect radiation effects occur exclusively. The main result is, that the OH'-radical is by far the most effective radical to destroy thymine molecules. The relative contributions of direct and indirect radiation effects to lethal actions of ionizing radiation was investigated in yeast cells. The radical spectrum of water radiolysis was changed by bubbling the cell suspensions with different gases. The main result is, that there are no lethal radiation effects du to the action of water radicals

  1. Radiation Effects Research Foundation bibliography of published papers, 1989

    International Nuclear Information System (INIS)

    1990-01-01

    This issue is the bibliography of the publication by the staffs of the Radiation Effects Research Institute (RERF) in 1989. Titles in original and English language with author names are enumerated. Indexes by research areas and by author name are also attached. (J.P.N.) 62 refs

  2. Radiation effects on and dose enhancement of electronic materials

    International Nuclear Information System (INIS)

    Srour, J.R.; Long, D.M.

    1984-01-01

    This book describes radiation effects on and dose enhancement factors for electronic materials. Alteration of the electrical properties of solid-state devices and integrated circuits by impinging radiation is well-known. Such changes may cause an electronic subsystem to fail, thus there is currently great interest in devising methods for avoiding radiation-induced degradation. The development of radiation-hardened devices and circuits is an exciting approach to solving this problem for many applications, since it could minimize the need for shielding or other system hardening techniques. Part 1 describes the basic mechanisms of radiation effects on electronic materials, devices, and integrated circuits. Radiation effects in bulk silicon and in silicon devices are treated. Ionizing radiation effects in silicon dioxide films and silicon MOS devices are discussed. Single event phenomena are considered. Key literature references and a bibliography are provided. Part II provides tabulations of dose enhancement factors for electronic devices in x-ray and gamma-ray environments. The data are applicable to a wide range of semiconductor devices and selected types of capacitors. Radiation environments discussed find application in system design and in radiation test facilities

  3. Radiation effects on integrated circuits used in high energy research

    International Nuclear Information System (INIS)

    Kanofsky, A.S.; Yost, B.; Farr, W.

    1990-01-01

    The authors report here on radiation effects on two amplifiers used in high energy experiments. These are standard devices that are produced by LeCroy. They describe each of the devices and the experimental techniques. Finally, they present and discuss the results of the measurements. 5 figs

  4. Radiation Effects Research Foundation bibliography of published papers, 1988

    International Nuclear Information System (INIS)

    1989-01-01

    This issue is the bibliography of the publication by the staffs of the Radiation Effects Research Institute (RERF) in 1988. Titles in original and English language with author names are enumerated. Indeces by research areas and by author name are also attached. (J.P.N.) 99 refs

  5. Radiation effects on polyacetylenes having substituents

    International Nuclear Information System (INIS)

    Higashimura, Toshinobu; Tang, Ben-Zhong; Masuda, Toshio; Yamaoka, Hitoshi; Matsuyama, Tomochika.

    1985-01-01

    Effects of γ-ray irradiation on high molecular weight polyacetylenes with various substituents were studied in air and in vacuum. The molecular weights of polymers from aliphatic disubstituted acetylenes (2-octyne and 2-decyne) remarkably reduced with irradiation in air. Their G values for chain scission in air were as high as 3 - 12, whereas no degradation occurred in vacuum. The degraded polymers contain carbonyl and hydroxyl groups, and are soluble in polar solvents such as methyl ethyl ketone and acetone. In contrast, polymers of aromatic disubstituted acetylenes (1-phenyl-1-propyne and 1-chloro-2-phenylacetylene) hardly degraded in air even with irradiation up to 40 Mrad. The degradation behavior of poly(t-butylacetylene) was intermediate between those of the above aliphatic and aromatic polymers. Thus the radiolysis of polyacetylenes was found to be greatly dependent on the kind of substituents. (author)

  6. Thermal radiation effects on hydromagnetic flow

    International Nuclear Information System (INIS)

    Abdelkhalek, M.M.

    2005-01-01

    Numerical results are presented for the effects of thermal radiation, buoyancy and heat generation or absorption on hydromagnetic flow over an accelerating permeable surface. These results are obtained by solving the coupled nonlinear partial differential equations describing the conservation of mass, momentum and energy by a perturbation technique. This qualitatively agrees with the expectations, since the magnetic field exerts a retarding force on the free convection flow. A parametric study is performed to illustrate the influence of the radiation parameter, magnetic parameter, Prandtl number, Grashof number and Schmidt number on the profiles of the velocity components and temperature. The effects of the different parameters on the velocity and temperature profiles as well as the skin friction and wall heat transfer are presented graphically. Favorable comparisons with previously published work confirm the correctness of numerical results

  7. Radiation effect on polystyrene-divinylbenze

    International Nuclear Information System (INIS)

    Xiong Jie

    2008-06-01

    The SDB polymer had better irradiation resistance. The property of SDB was studied by the methods of FT-IR, SEM and GC/MS. With the increasing absorbed dose, the color of SDB turned yellow slowly and the increase of weight was also found to turn to be higher. The oxidation reaction was confirmed by the appearance of C=O and C--O. The SEM images of SDB had unobvious change. From the results of the quantity of the irradiated gas in air, it was found that the CO 2 had the highest content, the H 2 , CO, CH 4 and C 2 H 6 took turns. The phenomenon was explained clearly and the peroxides structures were also confirmed. (authors)

  8. Radiation effect on rocket engine performance

    Science.gov (United States)

    Chiu, Huei-Huang; Kross, K. W.; Krebsbach, A. N.

    1990-01-01

    Critical problem areas involving the effect of radiation on the combustion of bipropellants are addressed by formulating a universal scaling law in combination with a radiation-enhanced vaporization combustion model. Numerical algorithms are developed and data pertaining to the Variable Thrust Engine (VTE) and the Space Shuttle Main Engine (SSME) are used to conduct parametric sensitivity studies to predict the principal intercoupling effects of radiation. The analysis reveals that low-enthalpy engines, such as the VTE, are vulnerable to a substantial performance setback due to radiative loss, whereas the performance of high-enthalpy engines such as the SSME are hardly affected over a broad range of engine operation. Combustion enhancement by radiative heating of the propellant has a significant impact on propellants with high absorptivity.

  9. Ionizing radiation effects on floating gates

    International Nuclear Information System (INIS)

    Cellere, G.; Paccagnella, A.; Visconti, A.; Bonanomi, M.

    2004-01-01

    Floating gate (FG) memories, and in particular Flash, are the dominant among modern nonvolatile memory technologies. Their performance under ionizing radiation was traditionally studied for the use in space, but has become of general interest in recent years. We are showing results on the charge loss from programmed FG arrays after 10 keV x-rays exposure. Exposure to ionizing radiation results in progressive discharge of the FG. More advanced devices, featuring smaller FG, are less sensitive to ionizing radiation that older ones. The reason is identified in the photoemission of electrons from FG, since at high doses it dominates over charge loss deriving from electron/hole pairs generation in the oxides

  10. Gamma radiation effects on liofilized human serum

    International Nuclear Information System (INIS)

    Padron Soler, E.; Romay Penabad, Z.; Chavez Ardanza, A.; Hernandez Gonzalez, C.; Martin Gonzalez, O.; Garcia Gonzalez, I.; Prieto Miranda, E.

    1995-01-01

    Human freeze dried serum was artificially contaminated with Flavobacterium sp. for studying the effects of gamma radiation of it. The radiobiological parameters of the contaminator were determined and the sterilization dose was set. The quality of the product irradiated at both, calculated sterilization dose (8.5 kGy) an another one about 25 kGy was determined. It was made according to: sterility testing, total proteins, pH enzymes (alanina-aminotransferase, aspartato-aminotransferase, alkaline phosphatase), protein electrophoresis, fast performance liquid chromatographic and effect on the cellular growth. From the latter was concluded that the calculated sterilization dose was adequate form keeping the biological properties and viability of the irradiated serum. Nevertheless, the dose of 25 k Gy was not adequate because of its dangerous effects on the cell culture

  11. Radiation effects on lead silicate glass surfaces

    International Nuclear Information System (INIS)

    Wang, P.W.; Zhang, L.P.; Borgen, N.; Pannell, K.

    1996-01-01

    Radiation-induced changes in the microstructure of lead silicate glass were investigated in situ under Mg K α irradiation in an ultra-high vacuum (UHV) environment by X-ray photoelectron spectroscopy (XPS). Lead-oxygen bond breaking resulting in the formation of pure lead was observed. The segregation, growth kinetics and the structural relaxation of the lead, with corresponding changes in the oxygen and silicon on the glass surfaces were studied by measuring the time-dependent changes in concentration, binding energy shifts, and the full width at half maximum. A bimodal distribution of the oxygen XPS signal, caused by bridging and non-bridging oxygens, was found during the relaxation process. All experimental data indicate a reduction of the oxygen concentration, a phase separation of the lead from the glass matrix, and the metallization of the lead occurred during and after the X-ray irradiation. (author)

  12. FALLOUT RADIATION: EFFECTS ON THE SKIN

    Energy Technology Data Exchange (ETDEWEB)

    Conard, R. A.; Cronkite, E. P.; Bond, V. P.

    1963-02-06

    Until recently it has been generally assumed that injury to the skin from ionizing radiation was not a serious hazard associated with the detonation of nuclear dcvices. However, in 1954 the importance of this hazard became apparent when widespread lesions of the skin developed in a large group of people accidentally exposed to fallout radiation in the Marshall Islands following the experimental detonation of a large nuclear device. The accident in the Marshall Islands affords an example of large numbers of lesions of the skin in human beings from the fallout. Studies have been documented and will be referred to frequently in this chapter. The possibility of such accidents must be considered seriously in view of the increasingly widespread use of radioisotopes.

  13. Radiation effect onto biodiversity of spiders

    International Nuclear Information System (INIS)

    Mehrabova, M.A.; Naghiyev, J.A; Huseynov, N.I; Topchiyeva, Sh.A.; Hasanov, N.H.

    2010-01-01

    At present time spiders are one of the considerably diverse groups of living organisms in fauna of Azerbayjan Republic. They play an important in environmental chain, being the main group of wild arthropodas in most biocoenoses. Therefore, it's not surprised that recently an increased interest has being observed to the study of spiders as indicators of environmental conditions. Spiders have been collected in polluted areas, their identification and sampling of soil, water and plants has been conducted. The degree of radionuclides' impact on the number and distribution of spiders and their venom in the observed zones of Azerbaijan has been revealed and preliminarily predicted. The number of the collected spiders equals to 292 which has been determined later at an electronic identifier Spinnen Mitteleuropas. The radionuclides in spiders have been determined at Canberra facility. Different natural radioactive elements were revealed in the investigated samples.

  14. Gamma radiation effects on peanut skin antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Adriano Costa de [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Canniatti-Brazaca, Solange Guidolin; Vieira, Thais Maria Ferreira de Souza; Regitano-d' Arce, Marisa Aparecida Bismara; Calori-Domingues, Maria Antonia, E-mail: sgcbraza@usp.b, E-mail: tvieira@esalq.usp.b, E-mail: mabra@esalq.usp.b, E-mail: macdomin@esalq.usp.b [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Dept. de Agroindustria, Alimentos e Nutricao

    2011-07-01

    Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The viability of using natural sources of antioxidants to replace synthetic antioxidants was assessed. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays at a dose rate of 7.5 kGy/h using a {sup 60}Co source. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached deodorized (RBD) soybean oil that was free from synthetic antioxidants. The oxidative stability of the oil samples was determined using the Rancimat method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. Ethanolic extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Rancimat method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT but lower than THBQ. The present study confirmed that gamma radiation did not affect the peanut skin extracts' antioxidative level when added to soybean oil. The induction period of the control soybean oil was 5.7 h, while soybean oil with added ethanolic peanut skin extract had an induction period of 7.2 h, on average. (author)

  15. Gamma radiation effects on peanut skin antioxidants

    International Nuclear Information System (INIS)

    Camargo, Adriano Costa de; Canniatti-Brazaca, Solange Guidolin; Vieira, Thais Maria Ferreira de Souza; Regitano-d'Arce, Marisa Aparecida Bismara; Calori-Domingues, Maria Antonia

    2011-01-01

    Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The viability of using natural sources of antioxidants to replace synthetic antioxidants was assessed. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays at a dose rate of 7.5 kGy/h using a 60 Co source. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached deodorized (RBD) soybean oil that was free from synthetic antioxidants. The oxidative stability of the oil samples was determined using the Rancimat method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. Ethanolic extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Rancimat method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT but lower than THBQ. The present study confirmed that gamma radiation did not affect the peanut skin extracts' antioxidative level when added to soybean oil. The induction period of the control soybean oil was 5.7 h, while soybean oil with added ethanolic peanut skin extract had an induction period of 7.2 h, on average. (author)

  16. Solar Radiation effect on the bituminous binder

    International Nuclear Information System (INIS)

    Tadeo Rico, A.; Torres Perez, A.

    2010-01-01

    Asphalt, used as binder in road construction, becomes more brittle and harder during working life on the surface of the road pavement, conducting toward their deterioration. This is caused by the oxidation of the molecular functional groups of the asphalt molecular structure. Moreover, it is observed that ultraviolet radiation increases the oxidation process. However, the effect of solar light on the asphalt degradation has been poorly researched. The aim of this work is to study asphalt ageing caused by effect of solar radiation, by using standard test. Four commercial asphalts from different companies were selected: two with penetration number 50/70, and the other two polymer modified asphalts. From each of the asphalts forty samples were taken off and placed in four different aging conditions of temperature and radiation for a period ranging from 40 to 500 days. Ring and Ball test, and Fraass breaking Point test, were used to analyse the changes of asphalt properties after exposition to solar radiation. The results of the four analyzed asphalts showed a distinct behaviour; not only in the test temperature increase but also in the rate. Another experiment was carried out. Samples from a hot mix asphalt batch were placed under solar radiation, and were compacted by the Marshall procedure after increasing periods of time. Density and resistance to plastic flow using Marshall Apparatus were measured. Results showed an increase in the stability of samples under radiation. Both experiments show that the solar radiation is enough to cause changes in the asphalt molecular structure due to oxidation. So that, the study of the effect of the solar radiation on the asphalt properties could be a good tool to asses the performances of asphalt pavement. (Author) 26 refs.

  17. A study of the Teachers` Academy for Mathematics and Science

    Energy Technology Data Exchange (ETDEWEB)

    Brett, B.; Scheirer, M.A.; Raizen, S.

    1994-09-15

    The Teachers` Academy for Mathematics and Science in Chicago (TAMS) is a freestanding institution founded in 1989 by scientists and a variety of other stakeholders, to advance the systemic reform of mathematics and science education in Chicago`s public schools. It focuses on the ``re-tooling`` of its elementary level teachers. The TAMS program, which has been funded in part by the DOE, contributes to strategic goals two through five of the Office of University and Science Education (OUSE). This evaluation of TAMS by the National Center for Improving Science Education is primarily a qualitative study that summarizes the history and current status of the organization and its programs. Data was obtained through extensive interviews, observations, and document review, using a framework of templates to guide data collection and analyses. The findings are organized around a series of lessons learned from the first three years of TAMS and conclusions about its current status.

  18. [Science and society. Guidelines for the Leopoldina Study Center].

    Science.gov (United States)

    Hacker, Jörg

    2014-01-01

    In order to adequately perform its many diverse tasks as a scholars' society and as the German National Academy of Sciences, the Deutsche Akademie der Naturforscher Leopoldina needs to view itself in a historical context. This can only happen as part of a culture of remembrance which fosters the memory of the Leopoldina's past and subjects this to a critical analysis in the context of the history of science and academies. The newly founded Leopoldina Study Center for the History of Science and Science Academies is to be a forum that pursues established forms of historical research at the Leopoldina, organizes new scientific projects, and presents its findings to the public. The aim is to involve as many Leopoldina members as possible from all of its disciplines, as well as to collaborate with national and international partners.

  19. Biological radiation effects of Radon in Drosophila

    International Nuclear Information System (INIS)

    Pimentel P, A.E.

    1995-01-01

    In order to contribute to the knowledge on the effects of radon and its decay products, the aim of this investigation is to study the biological effects of radon using Drosophila melanogaster throught the somatic mutation and recombination test (SMART) and the analysis of some adaptative factors exposing larvaes to controlled radon atmosphers, considering that this insect could be used as biological monitor. Using the somatic mutation test a mutagenic effect was observed proportional to radon concentration, into an interval of 1 ± 0.3 to 111 ± 7.4 KBq/m 3 equivalent to doses under 0.0106 Gy. The correlation analysis gives a linear (r=0.80) relationship with a positive slope of 0.2217. The same happens when gamma rays are used in the interval of 1 to 20 Gy, given a linear dose-dependent effect (r=0.878) is obtained; nevetheless the slop is smaller (m=0.003) than for radon. Analysing the results of adaptative factors of the nine exposed generations, it was found that probably radon exposition induced dominant lethals during gametogenesis or/and a selection of the more component gamets of the treated individuals in larval state. It was reflected in the significant decrease on fecundity of the generation exposed. Nevertheless the laying eggs had an increase in egg-to-adult viability and the develop velocity was higher than in control for 3 KBq/m 3 , this suggest that radon concentrations used were able to induce repair mechanisms. These data agree with the Hormesis hypothesis that says: low doses have positive effects on health. It was not possible to obtain a dose-effect relationship except with the develop velocity where it was found a dose-effect inverse proportion. In conclusion, Drosophila melanogaster could be a good system to obtain in vivo damaged induction concentration dependent of radon and its decay products, as well as to study the effects in an exposed population by the analysis of adaptative factors. (Author)

  20. Students' Preconceptions and Perceptions of Science-Oriented Studies

    NARCIS (Netherlands)

    Korpershoek, Hanke; Kuyper, Hans; Bosker, Roel; van der Werf, Greetje

    2013-01-01

    Do non-science, technology, engineering, and mathematics (STEM) students' views about STEM studies correspond with how STEM students actually perceive these studies? This paper deals with this issue by comparing higher education students' attitudes towards STEM studies between those who actually did

  1. Newspapers in Science Education: A Study Involving Sixth Grade Students

    Science.gov (United States)

    Lai, Ching-San; Wang, Yun-Fei

    2016-01-01

    The purpose of this study was to explore the learning performance of sixth grade elementary school students using newspapers in science teaching. A quasi-experimental design with a single group was used in this study. Thirty-three sixth grade elementary school students participated in this study. The research instruments consisted of three…

  2. An ethnographic study of the construction of science on television

    Science.gov (United States)

    Dhingra, Koshi

    1999-10-01

    The medium of television is an important manifestation of popular culture. Television stories and images frequently represent the position occupied by science and scientists in society. This study focuses on three questions. First, what is the form and content of the science that is constructed on television programs in which high school students see science? Second, how do television practitioners who deal with science approach and think about their work? Third, in what ways do high school students appropriate the science in these programs? Ethnographic methods, which did not include the technique of participant observation, were used to address these questions. Two types of text provided the basis for ethnographic analysis. First, text whose production was beyond the control of the researcher was used in the form of approximately 10 hours of programming, which included both fictional and non-fictional genres. Selection was based upon the results of questionnaires, in which students were asked to list those programs in which they saw the most science together with their reasons for each choice. Second, text whose production was somewhat within my control as researcher was used in the form of transcripts of interviews with television practitioners and students. In addition, written responses to the researcher's questions and transcripts of student discussion groups are texts that fall into this second category. The findings point to the centrality of the notion of the nature of science, which is constructed by a variety of factors. These include, first, story---representing events, people and the process of science on television. Story is shaped by plot, discourse, characters and genre. Second, images work to construct a nature of science and, in turn, constitute choices made about the composition, sequence and duration of shots. Third, who the television practitioners who produce a program are in conjunction with the culture of the institution they work for

  3. Radiation effects on custom MOS devices

    International Nuclear Information System (INIS)

    Harris, R.

    1999-05-01

    This Thesis consists of four chapters: The first is primarily for background information on the effects of radiation on MOS devices and the theory of wafer bonding; the second gives a full discussion of all practical work carried out for manufacture of Field Effect test Capacitors, the third discusses manufacture of vacuum insulator Field Effect Transistors (FET's) and the fourth discusses the testing of these devices. Using a thermally bonded field effect capacitor structure, a vacuum dielectric was studied for use in high radiation environments with a view to manufacturing a CMOS compatible, micro machined transistor. Results are given in the form of high frequency C-V curves before and after a 120 kGy(Si), 12 MRad(Si), dose from a Co 60 source showing a 1 Volt shift. The work is then extended to the design and manufacture of a micro machined, under-etch technique, Field Effect Transistor for use in high radiation areas. Results are shown for Threshold, Subthreshold and Transfer characteristics before and after irradiation up to a total dose of 100kGy or 10MRad. The conclusion from this work is that it should be possible to commercially manufacture practical vacuum dielectric field effect transistors which are radiation hard to at least 120 kGy(Si). (author)

  4. Ionizing radiation effect on enzymes. I

    International Nuclear Information System (INIS)

    Libicky, A.; Chottova, O.; Fidlerova, J.; Urban, J.

    1980-01-01

    The effect was studied of gamma radiation on the proteolytic activity of pancreatin prepared either by separating enzymes from an activated extract of the pancreas, containing 2.15% of lipids, or by drying the not completely activated ground pancreas, containing 6.14% of lipids. A part of the first sample in which the proportion of lipids was additionally increased to 16.55% was also irradiated. The moisture content was practically the same in all three samples. The source of radiation was 60 Co, the dose rate 1.27 kGy/h. The samples of pancreatin in test-tubes were irradiated at 25 degC, doses ranging from 1x10 4 to 12x10 4 Gy. The results were statistically evaluated and are given in tables, and converted to the dried lipid-free substance they are expressed in graphs. The technological procedure of pancreatin preparation and the content of lipids do not influence the decrease in proteolytic activity (Graph 3). (author)

  5. Radiation effects on two-dimensional materials

    Energy Technology Data Exchange (ETDEWEB)

    Walker, R.C. II; Robinson, J.A. [Department of Materials Science, Penn State, University Park, PA (United States); Center for Two-Dimensional Layered Materials, Penn State, University Park, PA (United States); Shi, T. [Department of Mechanical and Nuclear Engineering, Penn State, University Park, PA (United States); Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI (United States); Silva, E.C. [GlobalFoundries, Malta, NY (United States); Jovanovic, I. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI (United States)

    2016-12-15

    The effects of electromagnetic and particle irradiation on two-dimensional materials (2DMs) are discussed in this review. Radiation creates defects that impact the structure and electronic performance of materials. Determining the impact of these defects is important for developing 2DM-based devices for use in high-radiation environments, such as space or nuclear reactors. As such, most experimental studies have been focused on determining total ionizing dose damage to 2DMs and devices. Total dose experiments using X-rays, gamma rays, electrons, protons, and heavy ions are summarized in this review. We briefly discuss the possibility of investigating single event effects in 2DMs based on initial ion beam irradiation experiments and the development of 2DM-based integrated circuits. Additionally, beneficial uses of irradiation such as ion implantation to dope materials or electron-beam and helium-beam etching to shape materials have begun to be used on 2DMs and are reviewed as well. For non-ionizing radiation, such as low-energy photons, we review the literature on 2DM-based photo-detection from terahertz to UV. The majority of photo-detecting devices operate in the visible and UV range, and for this reason they are the focus of this review. However, we review the progress in developing 2DMs for detecting infrared and terahertz radiation. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Ionizing radiation effect on enzymes. IV

    International Nuclear Information System (INIS)

    Libicky, A.; Fidlerova, J.; Husakova, A.; Urban, J.

    1981-01-01

    The effect was studied of 60 Co gamma radiation on the total proteolytic efficacy of pancreatin with gradually differentiated humidity, both in a preparation obtained by separating the active ingredients from an extract from the pancreas destroyed by autolysis, and in a preparation containing the remains of the pancreatic tissue, where the basic operation of manufacture was drying of the ground pancreas. The samples were irradiated with doses of 2.5x10 4 and 12x10 4 , or 14.2x10 4 Gy. The mean values found of the residual proteolytic efficacy expressed in the units of PhBs 3, calculated to the dried substance, are tabulated. At the same time the efficacy of samples before irradiation was tested. The evaluation of results included in the individual tables by variance analysis and Lord's u-test shows that there is no statistically significant difference between the mean values of the efficacy of samples with the initial humidity and the samples with increased humidity (maximally 16.20%). (author)

  7. Ionizing radiation effect on enzymes. III

    International Nuclear Information System (INIS)

    Libicky, A.; Chottova, O.; Fidlerova, J.; Urban, J.; Kubankova, V.

    1980-01-01

    A decrease in the efficacy of trypsin (determination according to PhBs 3 with the use of L-lysine ethyl ester chloride) was investigated in pancreatin obtained by enzyme precipitation from a pancreas extraction after autolysis, in the identical sample with an additionally increased content of lipids, in pancreatin containing parts of the pancreatic tissue, in crystalline trypsin, and in crystalline salt-free and lyophilized trypsine after irradiation with gamma rays from 60 Co, doses ranging from 1x10 4 Gy to 12x10 4 Gy. The results were statistically evaluated and after the conversion to dried or lipid-free substance expressed in graphs. The dependence of the efficacy on the radiation dose has a linear course in semi-logarithmic arrangement, similarly as it occurred in chymotrypsin and in the total proteolytic efficacy. The decrease in the efficacy of trypsin in the samples of pancreatin in percentage maintains the same sequence in the samples under study as it was in the decrease in the efficacy of chymotrypsin and the total proteolytic efficacy, but it is smaller. The decrease in the efficacy of pure enzyme is, similarly to chymotrypsin, greater than the decrease in the efficacy of the enzyme in pancreatin. The present ballast substances thus significantly influence stability. (author)

  8. Radiation effects on bovine taste bud membranes

    International Nuclear Information System (INIS)

    Shatzman, A.R.; Mossman, K.L.

    1982-01-01

    In order to investigate the mechanisms of radiation-induced taste loss, the effects of radiation on preparations of enriched bovine taste bud membranes were studied. Taste buds containing circumvallate papilae, and surrounding control epithelial tissues devoid of taste buds, were obtained from steers and given radiation doses of 0-7000 cGy (rad). Tissue fractions were isolated into membrane-enriched and heterogeneous components using differential and sucrose gradient centrifugation of tissue homogenates. The yield of membranes, as measured by protein content in the buoyant membrane-enriched fractions, was reduced in quantity with increasing radiation dose. The relation between radiation dose and membrane quantity in membrane-enriched fractions could be fit by a simple exponential model with taste bud-derived membranes twice as radiosensitive as membranes from control epithelial tissue. Binding of sucrose, sodium, and acetate and fluoride stimulation of adenylate cyclase were nearly identical in both irradiated and nonirradiated intact membranes. Radiation had no effect on fractions of heterogeneous components. While it is not clear what changes are occurring in enriched taste cell membranes, damage to membranes may play an important role in the taste loss observed in patients following radiotherapy

  9. Discursive Contextures of Science: Euro/West-Centrism and Science and Technology Studies

    Directory of Open Access Journals (Sweden)

    Amit Prasad

    2016-07-01

    Full Text Available Science and Technology Studies (STS by the very act of showing the multiplicity, contingency, and context-dependence of scientific knowledge and practice, provincialized modern science. Postcolonial interventions within STS have pursued this goal even further. Nevertheless, Euro/West-centrism continues to inflect not only scientific practices and lay imaginaries, but also sociological and historical analyses of sciences. In this article, drawing on my own training within STS – first under J.P.S. Uberoi, who was concerned with structuralist analysis of modernity and science, and thereafter under Andy Pickering, when we focused on material agency and temporal emergence and extensively engaged with Actor Network Theory - I emphasize the continuing role of Euro/West-centric discourses in defining the “self” and the “other” and in impacting epistemological and ontological interventions. More broadly, building on a concept of Michael Lynch’s, I call for excavation and analysis of discursive contextures of sciences. In the second section of the article, through a brief analysis of embryonic stem cell therapy in a clinic in Delhi, I show how with shifting transnational landscape of technoscience certain discursive contextures are being “deterritorialized” and left “stuttering.”

  10. Radiation effects on metals, alloys and cement

    International Nuclear Information System (INIS)

    Lucki, G.; Sciani, V.

    1988-12-01

    High - energy particle irradiation of materials brings as a consequence changes in their atomic structures that alter the electrical, magnetic and mechanical properties which are the most important characteristics for practical applications of metals and alloys. A review is made on experimental results of in-pile (IEA-RI reactor) and CV-28 cyclotron irradiated materials. Resistivity measurements on CuPd and FeNi alloys showed different behaviour during fast neutron irradiation. While CuPd had almost coincidental relaxation curves, FeNi presented a distinguishable short and long-range ordering with the critical order-disorder temperature at 515 0 C. Vacancy supersaturation curves of FeNiSi (49-49-2 at %), FeNiCr (49-95-49, 95-0,1 at. %), FeNiMo (50-50 at.% + 50 ppm) and pure FeNi (50-50 at.%), determined by means of the Magnetic After Effect are presented as an effective pre-selection method of nuclear materials before the destructive stage of void formation and swelling. A displacement of damage peak from 480 to 500 and 570 0 C was detected on pure AISI 321 stainless steel and with 0,05 wt.% and 0,10 wt.% of Nb additions by means of resistivity and micro-hardness. Ultrasound techniques applied to fast neutron irradiated portland cement paste (fluence 7,2 x 10 18 n/cm 2 ) showed a 24% decrease in its dynamic elasticity modulus. Helium diffusion on Au, Ag and Al foils irradiated in cyclotron was studied, suggesting a vacancy mechanism for single He atom diffusion. Embrittlement by Alpha particle implantation in cyclotron to simulate in-pile (n,α) reaction-was measured by high temperature creep on AISI 316 stainles steel. (author) [pt

  11. Biomedical Engineering and Cognitive Science Secondary Science Curriculum Development: A Three Year Study

    Science.gov (United States)

    Klein, Stacy S.; Sherwood, Robert D.

    2005-01-01

    This study reports on a multi-year effort to create and evaluate cognitive-based curricular materials for secondary school science classrooms. A team of secondary teachers, educational researchers, and academic biomedical engineers developed a series of curriculum units that are based in biomedical engineering for secondary level students in…

  12. Performance Enhancement of Power Transistors and Radiation effect

    International Nuclear Information System (INIS)

    Hassn, Th.A.A.

    2012-01-01

    The main objective of this scientific research is studying the characteristic of bipolar junction transistor device and its performance under radiation fields and temperature effect as a control element in many power circuits. In this work we present the results of experimental measurements and analytical simulation of gamma – radiation effects on the electrical characteristics and operation of power transistor types 2N3773, 2N3055(as complementary silicon power transistor are designed for general-purpose switching and amplifier applications), three samples of each type were irradiated by gamma radiation with doses, 1 K rad, 5 K rad, 10 K rad, 30 K rad, and 10 Mrad, the experimental data are utilized to establish an analytical relation between the total absorbed dose of gamma irradiation and corresponding to effective density of generated charge in the internal structure of transistor, the electrical parameters which can be measured to estimate the generated defects in the power transistor are current gain, collector current and collected emitter leakage current , these changes cause the circuit to case proper functioning. Collector current and transconductance of each device are calibrated as a function of irradiated dose. Also the threshold voltage and transistor gain can be affected and also calibrated as a function of dose. A silicon NPN power transistor type 2N3773 intended for general purpose applications, were used in this work. It was designed for medium current and high power circuits. Performance and characteristic were discusses under temperature and gamma radiation doses. Also the internal junction thermal system of the transistor represented in terms of a junction thermal resistance (Rjth). The thermal resistance changed by ΔRjth, due to the external intended, also due to the gamma doses intended. The final result from the model analysis reveals that the emitter-bias configuration is quite stable by resistance ratio RB/RE. Also the current

  13. Annual report of Radiation Effects Research Foundation, April 1, 1988 - March 31, 1989

    International Nuclear Information System (INIS)

    1990-01-01

    This annual report summarizes the research activities of the Radiation Effects Research Foundation in the fiscal year 1988. Outcome of the work is presented, covering the two major workshops for 'immunology' and for 'radiation-induced carcinogenesis' which were held in Hiroshima on November 28-29, 1988, and on March 16-18, 1989, respectively. Study meeting of 'medical radiation research program' and Japan-the U.S. joint meeting of 'DS 86' are reported, as well as the other scientific lectures and campus study seminars. Included are research abstracts published by the Research Foundation staff. The bibliography of papers, published in scientific journals and presented in scientific meetings, is provided. Appendices give the details of the aforementioned workshops, the continuing research issues, and the personnel list of the Radiation Effects Research Foundation. (N.K.)

  14. Implanted muon studies in condensed matter science

    International Nuclear Information System (INIS)

    Cox, S.F.J.

    1986-12-01

    The paper reviews the broad range of applications of implanted muons in condensed matter. Muon spin rotation is discussed, along with the studies in magnetism, muonion, metals and organic radicals. A description of muon spin relaxation is also given, as well as techniques and applications appropriate to pulsed muon sources. (UK)

  15. Impact of Precipitating Ice Hydrometeors on Longwave Radiative Effect Estimated by a Global Cloud-System Resolving Model

    Science.gov (United States)

    Chen, Ying-Wen; Seiki, Tatsuya; Kodama, Chihiro; Satoh, Masaki; Noda, Akira T.

    2018-02-01

    Satellite observation and general circulation model (GCM) studies suggest that precipitating ice makes nonnegligible contributions to the radiation balance of the Earth. However, in most GCMs, precipitating ice is diagnosed and its radiative effects are not taken into account. Here we examine the longwave radiative impact of precipitating ice using a global nonhydrostatic atmospheric model with a double-moment cloud microphysics scheme. An off-line radiation model is employed to determine cloud radiative effects according to the amount and altitude of each type of ice hydrometeor. Results show that the snow radiative effect reaches 2 W m-2 in the tropics, which is about half the value estimated by previous studies. This effect is strongly dependent on the vertical separation of ice categories and is partially generated by differences in terminal velocities, which are not represented in GCMs with diagnostic precipitating ice. Results from sensitivity experiments that artificially change the categories and altitudes of precipitating ice show that the simulated longwave heating profile and longwave radiation field are sensitive to the treatment of precipitating ice in models. This study emphasizes the importance of incorporating appropriate treatments for the radiative effects of precipitating ice in cloud and radiation schemes in GCMs in order to capture the cloud radiative effects of upper level clouds.

  16. Gamma and electron radiation effects on agricultural by-products with high fibre content

    International Nuclear Information System (INIS)

    Leonhardt, J.W.; Baer, M.; Nehring, K.

    1983-01-01

    Gamma and electron radiation effects on wheat straw, oat straw, barley straw, rye straw and dried green fodder are reported. In vitro and in vivo studies show that the digestibility of these agricultural by-products with high fibre content can be increased up to 80% and more at high doses. The increase of the digestibility is connected with a depolymerization of the cellulose and hemicellulose. (author)

  17. Asian Studies/Global Studies: Transcending Area Studies and Social Sciences

    Directory of Open Access Journals (Sweden)

    John Lie

    2012-03-01

    Full Text Available The post–World War II growth of area studies, and Asian studies in particular, posed a serious challenge to the mainstream social sciences. Yet the epistemic and institutional foundations of area studies were never well articulated or justified, and the post–Cold War years brought a pervasive sense of crisis to its intellectual mission and justification. In particular, the author focuses on the tensions, if not contradictions, between social science disciplines and area studies. In advocating a more integrated human science, which depends more on mobile networks of scholars than on fixed fields of discipline-bound professors, the author suggests global studies as a fitting field of inquiry in the age of globalization.

  18. Administrative support of novice science teachers: A multiple case study

    Science.gov (United States)

    Iacuone, Leann

    Novice science teachers leave the confines of colleges and universities to embark on a new adventure in education where they aim to influence young minds, make a difference in the world, and share their love for their content. They have learned their pedagogical skills with the support and assistance of fellow classmates, a supporting professor, and a cooperating teacher. These teachers enter their new place of employment and are met with many unexpected challenges, such as a lack of resources, no one to ask questions of, and a busy staff with already established relationships, causing them to feel an overall lack of support and resulting in many new teachers rethinking their career choice and leaving the field of education within 5 years of entering. This multiple-case study investigated the administrative support 4 novice science teachers received during an academic year and the novice teachers' perceptions of the support they received to answer the following research question: How do novice science teachers who have consistent interactions with administrators develop during their first year? To answer this question, semistructured interviews, reflection journals, observations, resumes, long-range plans, and student discipline referrals were collected. The findings from this study show novice science teachers who had incidents occur in the classroom requiring administrative assistance and guidance felt more confident in enforcing their classroom management policies and procedures as the year progressed to change student behavior. The novice science teachers perceived administrators who provided resources including technology, office supplies, science supplies, and the guidance of a mentor as supportive. Novice science teachers who engaged in dialogue after administrative observations, were provided the opportunity to attend professional development outside the district, and had a mentor who taught the same discipline made more changes to their instructional

  19. Study of material science by neutron scattering

    International Nuclear Information System (INIS)

    Kim, H.J.; Yoon, B.K.; Cheon, B.C.; Lee, C.Y.; Kim, C.S.

    1980-01-01

    To develop accurate methods of texture measurement in metallic materials by neutron diffraction, (100),(200),(111) and (310) pole figures have been measured for the oriented silicon steel sheet, and currently study of correction methods for neutron absorption and extinction effects are in progress. For quantitative analysis of texture of polycrystalline material with a cubic structure, a software has been developed to calculate inverse pole figures for arbitrary direction specified in the speciman as well as pole figures for arbitrary chosen crystallographic planes from three experimental pole figures. This work is to be extended for the calculation of three dimensional orientation distribution function and for the evaluation of errors in the quantitative analysis of texture. Work is also for the study of N-H...O hydrogen bond in amino acid by observing molecular motions using neutron inelastic scattering. Measurement of neutron inelastic scattering spectrum of L-Serine is completed at 100 0 K and over the energy transfer range of 20-150 meV. (KAERI INIS Section)

  20. Postgraduate Studies in Librarianship and Information Science in Spain

    Science.gov (United States)

    Muñoz-Cañavate, Antonio; Larios-Suárez, Verónica

    2017-01-01

    This paper reviews the history and current situation of postgraduate studies in Librarianship and Information Science (LIS) at the university level in Spain before and after the development of the Bologna Process's European Higher Education Area (EHEA). It contextualizes the historical development of these studies, describing how official…

  1. Investigating Science Collaboratively: A Case Study of Group Learning

    Science.gov (United States)

    Zinicola, Debra A.

    2009-01-01

    Discussions of one urban middle school group of students who were investigating scientific phenomena were analyzed; this study was conducted to discern if and how peer interaction contributes to learning. Through a social constructivist lens, case study methodology, we examined conceptual change among group members. Data about science talk was…

  2. Design science research as research approach in doctoral studies

    CSIR Research Space (South Africa)

    Kotzé, P

    2015-08-01

    Full Text Available Since the use of design science research (DSR) gained momentum as a research approach in information systems (IS), the adoption of a DSR approach in postgraduate studies became more acceptable. This paper reflects on a study to investigate how a...

  3. A case study exploring science competence and science confidence of middle school girls from marginalized backgrounds

    Science.gov (United States)

    Garcia, Yeni Violeta

    The inclusion of learners from underrepresented background in biology field research experiences has not been widely explored in the literature. Increased access and equity to experiences for groups historically underrepresented in science, technology, engineering, and mathematics (STEM) has been identified as a priority for many, yet little is known about the components these experiences should have and what types of transformations participants undergo as a result of these experiences. This dissertation explored the systemic creation of an intervention purposely designed to serve middle school girls from underrepresented backgrounds, the implementation of such intervention, and effect on the girls' science competence and science confidence. El Espejo, Spanish for "The Mirror," was an ongoing field ecology research program for middle schools girls founded in 2009 at a local interdisciplinary learning center. Girls from all walks of life had the opportunity to be apprentice researchers and to work with scientists and science educators from the local community. All activities were strategically designed to promote student-led inquiry, career awareness, cultural awareness, and opportunities for research and mentorship for girls from underrepresented backgrounds. An increased understanding of if, how, and why this experience was perceived by the girls to be life changing was of importance to add to the conversations that seek ways to inspire and prepare this generation of students to be the next generation of scientists. The study built on systems theory, and on theories that were embedded in the participants' system: critical race theory, identity theory, and experiential learning theory, grounded in the context of the lived experiences of girls from underrepresented backgrounds. The girls' experiences were captured through journals, observer participant notes, photo-documentation, artifacts (posters, videos) created by the girls, and by using science perception

  4. Impact of Initiatives to Implement Science Inquiry: A Comparative Study of the Turkish, Israeli, Swedish and Czech Science Education Systems

    Science.gov (United States)

    Heinz, Jana; Enghag, Margareta; Stuchlikova, Iva; Cakmakci, Gultekin; Peleg, Ran; Baram-Tsabari, Ayelet

    2017-01-01

    This empirical study investigates factors that influence the implementation of science inquiry in the education systems of Turkey, Israel, Sweden and the Czech Republic. Data was collected by means of recordings of science experts' discussions as part of an EU-funded project called Science-Teacher Education Advanced Methods (2009-2012). Results of…

  5. Nature of Science Lessons, Argumentation and Scientific Discussions among Students in Science Class: A Case Study in a Successful School

    Science.gov (United States)

    Ozturk, Elif; Ucus, Sukran

    2015-01-01

    Argumentation is highlighted as one of the most important activities of science education by many researchers. The main aim of this research is to examine primary school students' nature of science classes and argumentation skills in terms of their academic success in primary science classes. Thus, the main interest of the study is centered on the…

  6. Nature of Science Lessons, Argumentation and Scientific Discussions among Students in Science Classes: A Case Study in a Successful School

    Science.gov (United States)

    Ozturk, Elif; Ucus, Sukran

    2015-01-01

    Argumentation is highlighted as one of the most important activities of science education by many researchers. The main aim of this research is to examine primary school students' nature of science classes and argumentation skills in terms of their academic success in primary science classes. Thus, the main interest of the study is centered on the…

  7. Integrating Science and Technology: Using Technological Pedagogical Content Knowledge as a Framework to Study the Practices of Science Teachers

    Science.gov (United States)

    Pringle, Rose M.; Dawson, Kara; Ritzhaupt, Albert D.

    2015-01-01

    In this study, we examined how teachers involved in a yearlong technology integration initiative planned to enact technological, pedagogical, and content practices in science lessons. These science teachers, engaged in an initiative to integrate educational technology in inquiry-based science lessons, provided a total of 525 lesson plans for this…

  8. Life Science Students' Attitudes, Interest, and Performance in Introductory Physics for Life Sciences: An Exploratory Study

    Science.gov (United States)

    Crouch, Catherine H.; Wisittanawat, Panchompoo; Cai, Ming; Renninger, K. Ann

    2018-01-01

    In response to national calls for improved physical sciences education for students pursuing careers in the life sciences and medicine, reformed introductory physics for life sciences (IPLS) courses are being developed. This exploratory study is among the first to assess the effect of an IPLS course on students' attitudes, interest, and…

  9. Understanding the Influence of Learners' Forethought on Their Use of Science Study Strategies in Postsecondary Science Learning

    Science.gov (United States)

    Dunn, Karee E.; Lo, Wen-Juo

    2015-01-01

    Understanding self-regulation in science learning is important for theorists and practitioners alike. However, very little has been done to explore and understand students' self-regulatory processes in postsecondary science courses. In this study, the influence of science efficacy, learning value, and goal orientation on the perceived use of…

  10. Radiation effects in pigtailed GaAs and GaA1As LEDs

    International Nuclear Information System (INIS)

    Barnes, C.E.

    1981-06-01

    Permanent and transient radiation effects have been studied in Plessey pigtailed, high radiance GaAs and GaAlAs LEDs using neutron, gamma ray and X-ray sources. The radiation-induced source of degradation in these devices was determined by also examining both bare, unpigtailed LEDs and separate samples of the Corning fibers used as pigtails. No transient effects were observed in the unpigtailed LEDs during either pulsed neutron or X-ray exposure. In contrast, the Corning doped silica fibers exhibited strong transient attenuation following pulsed X-ray bombardment. Permanent neutron damage in these pigtailed LEDs consisted essentially of light output degradation in the LED itself. Permanent gamma ray effects due to a Co-60 irradiation of 1 megarad were restricted to a small increase in attenuation in the fiber. The two primary radiation effects were then transient attenuation in the fiber pigtail and permanent neutron-induced degradation of the LED

  11. Annual report of Radiation Effects Research Foundation, April 1, 1989 - March 31, 1990

    International Nuclear Information System (INIS)

    1991-01-01

    This annual report summarizes the research activities of the Radiation Effects Research Foundation in the fiscal year, 1989. Outcome of the work is presented, covering epidemiology, Adult Health Survey Program, cytogenetics, genetic biochemical survey, immunology, cytobiology, and statistics. Symposium entitled 'update information on effects of radiation', held on October 8, 1989, and the final workshop on 'aging', held on March 29-31, 1990, are outlined, accompanied by the other scientific lectures and campus study seminars. The report also includes research abstracts published by the Research Foundation staff. Bibliography of papers, published in scientific journals and presented in scientific meetings, is provided. Appendices give the proceedings of the aforementioned workshop on 'aging', the continuing research issues, and the personal list of the Radiation Effects Research Foundation. (N.K.)

  12. Radiation effects on regeneration and T-cell-inducing function of the thymus

    International Nuclear Information System (INIS)

    Hirokawa, K.; Sado, T.

    1984-01-01

    Radiation effects on regeneration and T-cell-inducing function of the thymus were studied in three sets of experiments. When TXB mice were grafted with 1-week-old thymus which had been previously irradiated at various doses, an exponential decrease was observed in the morphological regeneration of the thymus grafts and in their T-cell-inducing function at doses of 600 R and over, showing about 10% that of the control at 1500 R. When in situ thymus of adult mice was locally irradiated, the radiation effect on T-cell-inducing function was less pronounced as compared with the first experiment; i.e., about 40% of the control at 1797 R. When in situ thymus of 1-day-old newborn mice was locally irradiated, regeneration potential of 1-day-old newborn thymus was highly resistant to radiation exposure and no effect on immunological functions was observed even by local irradiation of 2000 R

  13. Studies in Low-Energy Nuclear Science

    International Nuclear Information System (INIS)

    Brune, Carl R.; Grimes, Steven M.

    2006-01-01

    This report presents a summary of research projects in the area of low energy nuclear reactions and structure, carried out between 1 January 2003 and 31 December 2005 and supported by U.S. DOE grant number DE-FG03-03NA00074. Cross sections measured with high resolution have been subjected to an Ericson theory analysis to infer information about the nuclear level density. Other measurements were made of the spectral shape of particles produced in evaporation processes; these also yield level density information. A major project was the development of a new Hauser-Feshbach code for analyzing such spectra. Other measurements produced information on the spectra of gamma rays emitted in reactions on heavy nuclei and gave a means of refining our understanding of gamma-ray strength functions. Finally,reactions on light nuclei were studied and subjected to an R-matrix analysis. Cross sections fora network of nuclear reactions proceedingthrough a given compound nucleus shouldgreatly constrain the family of allowed parameters. Modifications to the formalism andcomputer code are also discussed.

  14. Studies in Low-Energy Nuclear Science

    International Nuclear Information System (INIS)

    Brune, Carl R.; Grimes, Steven M.

    2010-01-01

    This report presents a summary of research projects in the area of low energy nuclear reactions and structure, carried out between March 1, 2006 and October 31, 2009 which were supported by U.S. DOE grant number DE-FG52-06NA26187. We describe here research into low-energy nuclear reactions and structure. The statistical properties of nuclei have been studied by measuring level densities and also calculating them theoretically. Our approach of measuring level densities via evaporation spectra is able to reach a very wide range of nuclei by using heavy ion beams (we expect to develop experiments using radioactive beams in the near future). Another focus of the program has been on γ-ray strength functions. These clearly impact nuclear reactions, but they are much less understood than corresponding transmission coefficients for nucleons. We have begun investigations of a new approach, using γ-γ coincidences following radiative capture. Finally, we have undertaken several measurements of cross sections involving light nuclei which are important in various applications. The 9 Be(α,n) and B(d,n) reactions have been measured at Ohio University, while neutron-induced reactions have been measured at Los Alamos (LANSCE).

  15. The Science Manager's Guide to Case Studies

    Energy Technology Data Exchange (ETDEWEB)

    Branch, Kristi M.; Peffers, Melissa S.; Ruegg, Rosalie T.; Vallario, Robert W.

    2001-09-24

    This guide takes the science manager through the steps of planning, implementing, validating, communicating, and using case studies. It outlines the major methods of analysis, describing their relative merits and applicability while providing relevant examples and sources of additional information. Well-designed case studies can provide a combination of rich qualitative and quantitative information, offering valuable insights into the nature, outputs, and longer-term impacts of the research. An objective, systematic, and credible approach to the evaluation of U.S. Department of Energy Office of Science programs adds value to the research process and is the subject of this guide.

  16. Negotiating Science and Engineering: An Exploratory Case Study of a Reform-Minded Science Teacher

    Science.gov (United States)

    Guzey, S. Selcen; Ring-Whalen, Elizabeth A.

    2018-01-01

    Engineering has been slowly integrated into K-12 science classrooms in the United States as the result of recent science education reforms. Such changes in science teaching require that a science teacher is confident with and committed to content, practices, language, and cultures related to both science and engineering. However, from the…

  17. What science are you singing? A study of the science image in the mainstream music of Taiwan.

    Science.gov (United States)

    Huang, Chun-Ju; Allgaier, Joachim

    2015-01-01

    Previous research showed that pop music bands in the Western world have sometimes included science imagery in their lyrics. Their songs could potentially be helpful facilitators for science communication and public engagement purposes. However, so far no systematic research has been conducted for investigating science in popular music in Eastern cultures. This study explores whether science has been regarded as an element in the creation of popular mainstream music, and examines the content and quantity of distribution through an analysis of mainstream music lyrics, to reflect on the conditions of the absorption of science into popular culture. The results indicate that expressions related to astronomy and space science feature very prominently. Most of the lyrics are connected to emotional states and mood expressions and they are only very rarely related to actual issues of science. The implications for science communication and further research are discussed in the final section. © The Author(s) 2014.

  18. Review of radiation effects in solid-nuclear-waste forms

    International Nuclear Information System (INIS)

    Weber, W.J.

    1981-09-01

    Radiation effects on the stability of high-level nuclear waste (HLW) forms are an important consideration in the development of technology to immobilize high-level radioactive waste because such effects may significantly affect the containment of the radioactive waste. Since the required containment times are long (10 3 to 10 6 years), an understanding of the long-term cumulative effects of radiation damage on the waste forms is essential. Radiation damage of nuclear waste forms can result in changes in volume, leach rate, stored energy, structure/microstructure, and mechanical properties. Any one or combination of these changes might significantly affect the long-term stability of the nuclear waste forms. This report defines the general radiation damage problem in nuclear waste forms, describes the simulation techniques currently available for accelerated testing of nuclear waste forms, and reviews the available data on radiation effects in both glass and ceramic (primarily crystalline) waste forms. 76 references

  19. Radiation effects in IFMIF Li target diagnostic systems

    International Nuclear Information System (INIS)

    Molla, J.; Vila, R.; Shikama, T.; Horiike, H.; Simakov, S.; Ciotti, M.; Ibarra, A.

    2009-01-01

    Diagnostics for the lithium target will be crucial for the operation of IFMIF. Several parameters as the lithium temperature, target thickness or wave pattern must be monitored during operation. Radiation effects may produce malfunctioning in any of these diagnostics due to the exposure to high radiation fields. The main diagnostic systems proposed for the operation of IFMIF are reviewed in this paper from the point of view of radiation damage. The main tools for the assessment of the performance of these diagnostics are the neutronics calculations by using specialised codes and the information accumulated during the last decades on the radiation effects in functional materials, components and diagnostics for ITER. This analysis allows to conclude that the design of some of the diagnostic systems must be revised to assure the high availability required for the target system.

  20. Collaboration between science teacher educators and science faculty from arts and sciences for the purpose of developing a middle childhood science teacher education program: A case study

    Science.gov (United States)

    Buck, Gayle A.

    1998-12-01

    The science teacher educators at a midwestern university set a goal to establish a collaborative relationship between themselves and representatives from the College of Arts & Sciences for the purpose of developing a middle childhood science education program. The coming together of these two faculties provided a unique opportunity to explore the issues and experiences that emerge as such a collaborative relationship is formed. In order to gain a holistic perspective of the collaboration, a phenomenological case study design and methods were utilized. The study took a qualitative approach to allow the experiences and issues to emerge in a naturalistic manner. The question, 'What are the issues and experiences that emerge as science teacher educators and science faculty attempt to form a collaborative relationship for the purpose of developing a middle childhood science teacher program?' was answered by gathering a wealth of data. These data were collected by means of semi-structured interviews, observations and written document reviews. An overall picture was painted of the case by means of heuristic, phenomenological, and issues analyses. The researcher followed Moustakas' Phases of Heuristic Research to answer the questions 'What does science mean to me?' and 'What are my beliefs about the issues guiding this case?' prior to completing the phenomenological analysis. The phenomenological analysis followed Moustakas' 'Modification of the Van Kaam Methods of Analysis of Phenomenological Data'. This inquiry showed that the participants in this study came to the collaboration for many different reasons and ideas about the purpose for such a relationship. The participants also had very different ideas about how such a relationship should be conducted. These differences combined to create some issues that affected the development of curriculum and instruction. The issues involved the lack of (a) mutual respect for the work of the partners, (b) understanding about the

  1. Radiation effects in vitreous and devitrified simulated waste glass

    International Nuclear Information System (INIS)

    Weber, W.J.; Turcotte, R.P.; Bunnell, L.R.; Roberts, F.P.; Westsik, J.H. Jr.

    1979-01-01

    The long-term radiation stability of vitreous and partially devitrified forms of high-level waste glass was investigated in accelerated experiments by 266 Cm doping. The effects of radiation on microstructure, phase behavior, density, impact strength, stored energy, and leachability are reported to a cumulative radiation dose of 5 x 10 18 α decays/cm 3 . This dose produces saturation of radiation effects in most properties. 4 figures

  2. Radiation effects on thermal decomposition of inorganic solids

    International Nuclear Information System (INIS)

    Dedgaonkar, V.G.

    1985-01-01

    Radiation effects on the thermal decomposition characteristics of inorganic oxyanions like permanganates, nitrates, zeolites and particularly ammonium perchlorate (AP) have been highlighted.The last compound finds wide application as an oxidizer in solid rocket propellents and although several hundred papers have been published on it during the last 30-40 years, most of which from the point of view of understanding and controlling the decomposition behaviour, there are only a few reports available in this area following the radiation treatment. (author)

  3. Basic radiation effects in nuclear power electronics technology

    International Nuclear Information System (INIS)

    Gover, J.E.; Srour, J.R.

    1985-05-01

    An overview is presented of the effects of radiation in microelectronics technology. The approach taken throughout these notes is to review microscopic phenomena associated with radiation effects and to show how these lead to macroscopic effects in semiconductor devices and integrated circuits. Bipolar integrated circuits technology is reviewed in Appendix A. Appendix B gives present and future applications of radiation-tolerant microelectronics in nuclear power applications as well as the radiation tolerance requirements of these applications

  4. Data compilation for radiation effects on ceramic insulators

    International Nuclear Information System (INIS)

    Fukuya, Koji; Terasawa, Mititaka; Nakahigashi, Shigeo; Ozawa, Kunio.

    1986-08-01

    Data of radiation effects on ceramic insulators were compiled from the literatures and summarized from the viewpoint of fast neutron irradiation effects. The data were classified according to the properties and ceramics. The properties are dimensional stability, mechanical property, thermal property and electrical and dielectric properties. The data sheets for each table or graph in the literatures were made. The characteristic feature of the data base was briefly described. (author)

  5. Radiation Effects on Ytterbium-doped Optical Fibers

    Science.gov (United States)

    2014-06-02

    conducted on Er- doped fiber amplifiers (Lezius, et al., 2012; Ahrens, et al., 1999; Ahrens, Jaques , LuValle, DiGiovanni, & Windeler, 2001; Ott, 2004...Ahrens, R. G., Abate, J. A., Jaques , J. J., Presby, H. M., Fields, A. B., DiGiovanni, D. J., LuValle, M. J. (1999). Radiation reliability of rare... Jaques , J. J., LuValle, M. J., DiGiovanni, D. J., & Windeler, R. S. (2001). Radiation effects on optical fibers and amplifiers. Testing, Reliability

  6. CFD simulations and reduced order modeling of a refrigerator compartment including radiation effects

    International Nuclear Information System (INIS)

    Bayer, Ozgur; Oskay, Ruknettin; Paksoy, Akin; Aradag, Selin

    2013-01-01

    Highlights: ► Free convection in a refrigerator is simulated including radiation effects. ► Heat rates are affected drastically when radiation effects are considered. ► 95% of the flow energy can be represented by using one spatial POD mode. - Abstract: Considering the engineering problem of natural convection in domestic refrigerator applications, this study aims to simulate the fluid flow and temperature distribution in a single commercial refrigerator compartment by using the experimentally determined temperature values as the specified constant wall temperature boundary conditions. The free convection in refrigerator applications is evaluated as a three-dimensional (3D), turbulent, transient and coupled non-linear flow problem. Radiation heat transfer mode is also included in the analysis. According to the results, taking radiation effects into consideration does not change the temperature distribution inside the refrigerator significantly; however the heat rates are affected drastically. The flow inside the compartment is further analyzed with a reduced order modeling method called Proper Orthogonal Decomposition (POD) and the energy contents of several spatial and temporal modes that exist in the flow are examined. The results show that approximately 95% of all the flow energy can be represented by only using one spatial mode

  7. "Two Cultures" Topics for General Studies Science Courses.

    Science.gov (United States)

    Larson, James H.

    1982-01-01

    Theses proposed in C. P. Snow's book "The Two Cultures," including uncommunicative scientific and literary groups, gap between rich and poor, overpopulation, and nuclear war remain viable topics. Discusses the scientific and literary cultural gap and what can be done in general studies science courses to ameliorate the condition.…

  8. Marxism in Vygotskian Approaches to Cultural Studies of Science Education

    Science.gov (United States)

    Lima, Paulo, Jr.; Ostermann, Fernanda; Rezende, Flavia

    2014-01-01

    In this paper we initially address the main categories of Marxism, illustrating how Vygotsky has appropriated them as mediational meta-theoretical tools for building concepts for his psychological approach. In order to investigate the influence of Marxism in cultural studies of science education, we make an account of how current research,…

  9. Consumer Citizenship Curriculum Guides for Social Studies, English, Science, Mathematics.

    Science.gov (United States)

    MacKenzie, Louise; Smith, Alice

    These four consumer citizenship curriculum guides for social studies, English, science, and mathematics incorporate consumer education into these subject matter areas in grades 8-12. Each guide is organized around 10 main component/goals. They are basic economics in the marketplace, credit, consumer law/protection, banking skills, comparison…

  10. Social studies of science and us. Pt. 2

    International Nuclear Information System (INIS)

    Lyon, W.S.

    1984-01-01

    The author discusses some social impacts related with nuclear wastes, nuclear energy, nuclear weapons and radioanalytical chemistry. They are based on the talks delivered at the meeting of the Society for the Social Studies of Science (4S) in November 1983. (The first part of the publication does not contain references to nuclear problems). (A.L.)

  11. A Scale to Assess Science Activity Videos (SASAV): The Study of Validity and Reliability

    Science.gov (United States)

    Kara, Yilmaz; Bakirci, Hasan

    2018-01-01

    The purpose of the study was to develop an assessment scale for science activity videos that can be used to determine qualified science activity videos that can fulfill the objectives of activity based science education, help teachers to evaluate any science activity videos and decide whether to include into science learning process. The subjects…

  12. Signs of taste for science: a methodology for studying the constitution of interest in the science classroom

    Science.gov (United States)

    Anderhag, P.; Wickman, P.-O.; Hamza, K. M.

    2015-06-01

    In this paper we present a methodological approach for analyzing the transformation of interest in science through classroom talk and action. To this end, we use the construct of taste for science as a social and communicative operationalization, or proxy, to the more psychologically oriented construct of interest. To gain a taste for science as part of school science activities means developing habits of performing and valuing certain distinctions about ways to talk, act and be that are jointly construed as belonging in the school science classroom. In this view, to learn science is not only about learning the curriculum content, but also about learning a normative and aesthetic content in terms of habits of distinguishing and valuing. The approach thus complements previous studies on students' interest in science, by making it possible to analyze how taste for science is constituted, moment-by-moment, through talk and action in the science classroom. In developing the method, we supplement theoretical constructs coming from pragmatism and Pierre Bourdieu with empirical data from a lower secondary science classroom. The application of the method to this classroom demonstrates the potential that the approach has for analyzing how conceptual, normative, and aesthetic distinctions within the science classroom interact in the constitution of taste for, and thereby potentially also in the development of interest in science among students.

  13. How consistent are precipitation patterns predicted by GCMs in the absence of cloud radiative effects?

    Science.gov (United States)

    Popke, Dagmar; Bony, Sandrine; Mauritsen, Thorsten; Stevens, Bjorn

    2015-04-01

    Model simulations with state-of-the-art general circulation models reveal a strong disagreement concerning the simulated regional precipitation patterns and their changes with warming. The deviating precipitation response even persists when reducing the model experiment complexity to aquaplanet simulation with forced sea surface temperatures (Stevens and Bony, 2013). To assess feedbacks between clouds and radiation on precipitation responses we analyze data from 5 models performing the aquaplanet simulations of the Clouds On Off Klima Intercomparison Experiment (COOKIE), where the interaction of clouds and radiation is inhibited. Although cloud radiative effects are then disabled, the precipitation patterns among models are as diverse as with cloud radiative effects switched on. Disentangling differing model responses in such simplified experiments thus appears to be key to better understanding the simulated regional precipitation in more standard configurations. By analyzing the local moisture and moist static energy budgets in the COOKIE experiments we investigate likely causes for the disagreement among models. References Stevens, B. & S. Bony: What Are Climate Models Missing?, Science, 2013, 340, 1053-1054

  14. Science and ecological literacy in undergraduate field studies education

    Science.gov (United States)

    Mapp, Kim J.

    There is an ever-increasing number of issues that face our world today; from climate change, water and food scarcity, to pollution and resource extraction. Science and ecology play fundamental roles in these problems, and yet the understanding of these fields is limited in our society (Miller, 2002; McBride, Brewer, Berkowitz, and Borrie, 2013). Across the nation students are finishing their undergraduate degrees and are expected to enter the workforce and society with the skills needed to succeed. The deficit of science and ecological literacy in these students has been recognized and a call for reform begun (D'Avanzo, 2003 and NRC, 2009). This mixed-methods study looked at how a field studies course could fill the gap of science and ecological literacy in undergraduates. Using grounded theory, five key themes were data-derived; definitions, systems thinking, human's role in the environment, impetus for change and transference. These themes where then triangulated for validity and reliability through qualitative and quantitative assessments. A sixth theme was also identified, the learning environment. Due to limited data to support this themes' development and reliability it is discussed in Chapter 5 to provide recommendations for further research. Key findings show that this field studies program influenced students' science and ecological literacy through educational theory and practice.

  15. Marxism in Vygotskian approaches to cultural studies of science education

    Science.gov (United States)

    Lima Junior, Paulo; Ostermann, Fernanda; Rezende, Flavia

    2014-09-01

    In this paper we initially address the main categories of Marxism, illustrating how Vygotsky has appropriated them as mediational meta-theoretical tools for building concepts for his psychological approach. In order to investigate the influence of Marxism in cultural studies of science education, we make an account of how current research, sustained by Vygotsky's original and successor theories, has been appropriating meta-theoretical categories of dialectical materialism. Once we identified Cultural Studies of Science Education as a journal that would probably concentrate papers that follow these perspectives, we decided to take it as the context of this study. In the process of selecting the corpus to be reviewed from the editions published from 2006 to 2011, we have found that 16 % of the articles that matched keywords denoting frameworks related to the Vygotskian tradition developed and appropriated the categories of dialectical materialism. The quality and originality of contemporary development of CHAT denote that this framework has been playing a very important role in recent expansion of Vygotskian approaches to research in science education. Among the papers that we considered to develop and appropriate Vygotskian frameworks, incompletion in the appropriation of meta-theoretical categories of dialectical materialism and the misusage of dialectics intertwined with dialogism were highlighted. Our findings suggest that overcoming these limitations can enhance political analysis of sociocultural phenomena in the context of science education. It also represents a strengthening of the role of dialectical materialism in expanding sociocultural perspectives toward a better articulation between individual and institutional-centered analyses.

  16. Results of the studies of radiation ecology and radiation biology at the Institute of Biology of Komi Science Centre, Ural Division of Russian Academy of Sciences. (On the 40th anniversary of the radiation ecology department)

    International Nuclear Information System (INIS)

    Taskaev, A.I.; Kudyasheva, A.G.; Popova, O.N.; Materij, L.D.; Shuktomova, I.I.; Frolova, N.P.; Kozubov, G.M.; Zajnullin, V.G.; Ermakova, O.V.; Rakin, A.O.; Bashlykova, L.A.

    2000-01-01

    Materials on the history of foundation of the radiation Ecology Department at the Institute of Biology of the Komi Science Centre of the Russian Academy of Sciences on the occasion of its 40-th anniversary are presented. The results of studies on radiation effects in low doses on the plant and animal populations as well as on radionuclide migration in natural biogeocenoses by increased radiation levels are analyzed. The performed complex studies were used as the basis for developing methodological approaches to the solution of a number of problems on the surface radioecology. Multiyear studies on the biogeocenoses of increased radioactivity of different origin made it possible to obtain multiple materials, indicating high diversity and specificity of reaction of living organisms in response to the background low level chronic irradiation. Attention was paid to studies on the Komi contamination by atmospheric radioactive fall-outs as well as to studies on the consequences of radioactive contamination of the Ukrainian Polesje due to the Chernobyl accident [ru

  17. Study of the cell cycle control for human malignant mesothelioma lines. Interferon and radiations effect; Etude de la regulation du cycle cellulaire de lignees de mesotheliome malin humain. Effet de l'interferon et des radiations

    Energy Technology Data Exchange (ETDEWEB)

    Vivo, C

    1999-07-01

    In order to better understand the inhibition mechanisms of the IFN-R-HU on tumoral development, the IFN-R-U effect on MM lines has been studied. Three groups of lines has been distinguished: eight sensitive lines, two intermediate and three resistant. The sensitive lines showed a triple locking of the cell cycle: in phases S, G1 and G2. The study of the cell cycle control points function, realized by the MM lines radiation exposure showed the points function on G1/S and-or on G2/M and the dependence or non dependence of the cycle stop of the protein P53 and P21 W at F1/CIP1. (A.L.B.)

  18. Science/art - art/science: case studies of the development of a professional art product

    Energy Technology Data Exchange (ETDEWEB)

    Sesko, S.C.; Marchant, M.

    1997-02-24

    Objective was to follow the cognitive and creative processes demonstrated by student research participants as they integrated a developing knowledge of ``big`` science, as practiced at LLNL, into a personal and idiosyncratic visual, graphical, or multimedia product. The participants, all non-scientists, involved in this process, attended a series of design classes, sponsored by LLNL at the Art Center College of Design in Pasadena CA. As a result of this study, we have become interested in the possibility of similar characteristics between scientists and artists. We have also become interested in the different processes that can be used to teach science to non-scientists, so that they are able to understand and portray scientific information.

  19. NASA Earth Science Mission Control Center Enterprise Emerging Technology Study Study (MCC Technology Study)

    Science.gov (United States)

    Smith, Dan; Horan, Stephen; Royer, Don; Sullivan, Don; Moe, Karen

    2015-01-01

    This paper reports on the results of the study to identify technologies that could have a significant impact on Earth Science mission operations when looking out at the 5-15 year horizon (through 2025). The potential benefits of the new technologies will be discussed, as well as recommendations for early research and development, prototyping, or analysis for these technologies.

  20. Snowmass 2002: The Fusion Energy Sciences Summer Study

    International Nuclear Information System (INIS)

    Sauthoff, N.; Navratil, G.; Bangerter, R.

    2002-01-01

    The Fusion Summer Study 2002 will be a forum for the critical technical assessment of major next-steps in the fusion energy sciences program, and will provide crucial community input to the long-range planning activities undertaken by the DOE [Department of Energy] and the FESAC [Fusion Energy Sciences Advisory Committee]. It will be an ideal place for a broad community of scientists to examine goals and proposed initiatives in burning plasma science in magnetic fusion energy and integrated research experiments in inertial fusion energy. This meeting is open to every member of the fusion energy science community and significant international participation is encouraged. The objectives of the Fusion Summer Study are three: (1) Review scientific issues in burning plasmas to establish the basis for the following two objectives and to address the relations of burning plasma in tokamaks to innovative magnetic fusion energy (MFE) confinement concepts and of ignition in inertial fusion energy (IFE) to integrated research facilities. (2) Provide a forum for critical discussion and review of proposed MFE burning plasma experiments (e.g., IGNITOR, FIRE, and ITER) and assess the scientific and technological research opportunities and prospective benefits of these approaches to the study of burning plasmas. (3) Provide a forum for the IFE community to present plans for prospective integrated research facilities, assess present status of the technical base for each, and establish a timetable and technical progress necessary to proceed for each. Based on significant preparatory work by the fusion community prior to the July Snowmass meeting, the Snowmass working groups will prepare a draft report that documents the scientific and technological benefits of studies of burning plasmas. The report will also include criteria by which the benefits of each approach to fusion science, fusion engineering/technology, and the fusion development path can be assessed. Finally, the report

  1. Snowmass 2002: The Fusion Energy Sciences Summer Study; TOPICAL

    International Nuclear Information System (INIS)

    N. Sauthoff; G. Navratil; R. Bangerter

    2002-01-01

    The Fusion Summer Study 2002 will be a forum for the critical technical assessment of major next-steps in the fusion energy sciences program, and will provide crucial community input to the long-range planning activities undertaken by the DOE[Department of Energy] and the FESAC[Fusion Energy Sciences Advisory Committee]. It will be an ideal place for a broad community of scientists to examine goals and proposed initiatives in burning plasma science in magnetic fusion energy and integrated research experiments in inertial fusion energy. This meeting is open to every member of the fusion energy science community and significant international participation is encouraged. The objectives of the Fusion Summer Study are three: (1) Review scientific issues in burning plasmas to establish the basis for the following two objectives and to address the relations of burning plasma in tokamaks to innovative magnetic fusion energy (MFE) confinement concepts and of ignition in inertial fusion energy (IFE) to integrated research facilities. (2) Provide a forum for critical discussion and review of proposed MFE burning plasma experiments (e.g., IGNITOR, FIRE, and ITER) and assess the scientific and technological research opportunities and prospective benefits of these approaches to the study of burning plasmas. (3) Provide a forum for the IFE community to present plans for prospective integrated research facilities, assess present status of the technical base for each, and establish a timetable and technical progress necessary to proceed for each. Based on significant preparatory work by the fusion community prior to the July Snowmass meeting, the Snowmass working groups will prepare a draft report that documents the scientific and technological benefits of studies of burning plasmas. The report will also include criteria by which the benefits of each approach to fusion science, fusion engineering/technology, and the fusion development path can be assessed. Finally, the report will

  2. The art and science of selecting graduate students in the biomedical sciences: Performance in doctoral study of the foundational sciences.

    Science.gov (United States)

    Park, Hee-Young; Berkowitz, Oren; Symes, Karen; Dasgupta, Shoumita

    2018-01-01

    The goal of this study was to investigate associations between admissions criteria and performance in Ph.D. programs at Boston University School of Medicine. The initial phase of this project examined student performance in the classroom component of a newly established curriculum named "Foundations in Biomedical Sciences (FiBS)". Quantitative measures including undergraduate grade point average (GPA), graduate record examination (GRE; a standardized, computer-based test) scores for the verbal (assessment of test takers' ability to analyze, evaluate, and synthesize information and concepts provided in writing) and quantitative (assessment of test takers' problem-solving ability) components of the examination, previous research experience, and competitiveness of previous research institution were used in the study. These criteria were compared with competencies in the program defined as students who pass the curriculum as well as students categorized as High Performers. These data indicated that there is a significant positive correlation between FiBS performance and undergraduate GPA, GRE scores, and competitiveness of undergraduate institution. No significant correlations were found between FiBS performance and research background. By taking a data-driven approach to examine admissions and performance, we hope to refine our admissions criteria to facilitate an unbiased approach to recruitment of students in the life sciences and to share our strategy to support similar goals at other institutions.

  3. A Study of Chemically Reactive Species and Thermal Radiation Effects on an Unsteady MHD Free Convection Flow Through a Porous Medium Past a Flat Plate with Ramped Wall Temperature

    Directory of Open Access Journals (Sweden)

    Pandit K. K.

    2017-12-01

    Full Text Available An investigation of the effects of a chemical reaction and thermal radiation on unsteady MHD free convection heat and mass transfer flow of an electrically conducting, viscous, incompressible fluid past a vertical infinite flat plate embedded in a porous medium is carried out. The flow is induced by a general time-dependent movement of the vertical plate, and the cases of ramped temperature and isothermal plates are studied. An exact solution of the governing equations is obtained in closed form by the Laplace Transform technique. Some applications of practical interest for different types of plate motions are discussed. The numerical values of fluid velocity, temperature and species concentration are displayed graphically whereas the numerical values of skin friction, Nusselt number and Sherwood number are presented in a tabular form for various values of pertinent flow parameters for both ramped temperature and isothermal plates.

  4. A Study of Chemically Reactive Species and Thermal Radiation Effects on an Unsteady MHD Free Convection Flow Through a Porous Medium Past a Flat Plate with Ramped Wall Temperature

    Science.gov (United States)

    Pandit, K. K.; Sarma, D.; Singh, S. I.

    2017-12-01

    An investigation of the effects of a chemical reaction and thermal radiation on unsteady MHD free convection heat and mass transfer flow of an electrically conducting, viscous, incompressible fluid past a vertical infinite flat plate embedded in a porous medium is carried out. The flow is induced by a general time-dependent movement of the vertical plate, and the cases of ramped temperature and isothermal plates are studied. An exact solution of the governing equations is obtained in closed form by the Laplace Transform technique. Some applications of practical interest for different types of plate motions are discussed. The numerical values of fluid velocity, temperature and species concentration are displayed graphically whereas the numerical values of skin friction, Nusselt number and Sherwood number are presented in a tabular form for various values of pertinent flow parameters for both ramped temperature and isothermal plates.

  5. An Ongoing Investigation of Science Literacy: Results of a 22-Year Study Probing Students' Knowledge and Attitude Towards Science

    Science.gov (United States)

    Impey, C.; Buxner, S.; Antonellis, J.; CATS

    2013-04-01

    This talk presents findings related to our ongoing work investigating students' knowledge and attitudes towards science and technology. We present an overview of research studies and findings including a comparison of the science literacy measures of University of Arizona students compared to national studies, conceptions related to astrology, views of radiation, and students' pseudoscience and religious beliefs. We discuss implications for instructors and researchers interested in improving students' science literacy scores and diagnosing alternative beliefs.

  6. Treatment of cloud radiative effects in general circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.C.; Dudek, M.P.; Liang, X.Z.; Ding, M. [State Univ. of New York, Albany, NY (United States)] [and others

    1996-04-01

    We participate in the Atmospheric Radiation Measurement (ARM) program with two objectives: (1) to improve the general circulation model (GCM) cloud/radiation treatment with a focus on cloud verticle overlapping and layer cloud optical properties, and (2) to study the effects of cloud/radiation-climate interaction on GCM climate simulations. This report summarizes the project progress since the Fourth ARM Science Team meeting February 28-March 4, 1994, in Charleston, South Carolina.

  7. High school and college introductory science education experiences: A study regarding perceptions of university students persisting in science as a major area of study

    Science.gov (United States)

    Fredrick, L. Denise

    The focus of this study was to investigate college students' perception of high school and college introductory science learning experiences related to persistence in science as a major area of study in college. The study included students' perceptions of the following areas of science education: (1) teacher interpersonal relationship with students, (2) teacher personality styles, (3) teacher knowledge of the content, (4) instructional methods, and (5) science course content. A survey research design was employed in the investigative study to collect and analyze data. One hundred ninety two students participated in the research study. A survey instrument entitled Science Education Perception Survey was used to collect data. The researcher sought to reject or support three null hypotheses as related to participants' perceptions of high school and college introductory science education experiences. Using binomial regression analysis, this study analyzed differences between students persisting in science and students not persisting in science as a major. The quantitative research indicated that significant differences exist between persistence in science as a major and high school science teacher traits and college introductory science instructional methods. Although these variables were found to be significant predictors, the percent variance was low and should be considered closely before concluded these as strong predictors of persistence. Major findings of the qualitative component indicated that students perceived that: (a) interest in high school science course content and high school science teacher personality and interpersonal relationships had the greatest effect on students' choice of major area of study; (b) interest in college introductory science course content had the greatest effect on students' choice of major area of study; (c) students recalled laboratory activities and overall good teaching as most meaningful to their high school science

  8. A study in vitro on radiation effects by Er:YAG laser combined with the fluorine therapy in the acid resistance of the dental enamel submitted to orthodontical brackets

    International Nuclear Information System (INIS)

    Yoshiyasu, Roseli Y.A.

    2001-01-01

    Several researches have been demonstrating an increase in the resistance acid of the enamel surface when irradiated by some lasers types as Nd:YAG, C0 2 , Er:YAG, and others, mainly when combined with the fluoride therapy after the irradiation of the laser. This study in vitro used the laser of Er:YAG which density of energy of 8.1 J/cm 2 on the enamel about of orthodontical brackets of teeth extracted pre-molars. These teeth were then submitted to a rich way in S. mutans for twenty one days. The cases were analyzed: (1) enamel surface without any treatment, (2) enamel surface without any irradiation laser, but with therapy with acidulated phosphate fluoride, (3) enamel surface irradiated with laser of Er:YAG and (4) enamel surface irradiated by laser of Er:YAG and with application of acidulated phosphate fluoride. The results were analyzed through optical microscopy and scanning electron microscopy. The morphologic changes observed to the scanning electron microscopy suggest increase in the acid resistance of the enamel surface. However, to the optical microscopy, it was still possible to visualize undesirable white stains in the surface of the enamel. (author)

  9. Science comics as tools for science education and communication: a brief, exploratory study

    OpenAIRE

    M. Tatalovic

    2009-01-01

    Comics are a popular art form especially among children and as such provide a potential medium for science education and communication. In an attempt to present science comics in a museum exhibit I found many science themed comics and graphic books. Here I attempt to provide an overview of already available comics that communicate science, the genre of ‘science comics’. I also provide a quick literature review for evidence that comics can indeed be efficiently used for promoting scientific li...

  10. Science teachers teaching socioscientific issues (SSI): Four case studies

    Science.gov (United States)

    Lee, Hyunju

    Socioscientific issues (SSI) are a class of issues that represent the social, ethical, and moral aspects of science in society. The need for the inclusion of SSI into science curricula has been generally accepted, but relatively few science teachers have incorporated SSI into their courses. Most science teachers feel that their most important task by far is to teach the principles of science, and any substantive pedagogical changes represent a burden. However, there are some teachers who address SSI out of personal initiatives. This dissertation study investigates four high school science teachers who address SSI out of their own initiative and explores their deeper inspirations, values, philosophies, and personal ideals that lead them to teach SSI. The overall approach is based on essentialist methodology (Witz, Goodwin, Hart, & Thomas, 2001; Witz, 2006a) with its focus on "the participant as ally" and "essentialist portraiture." The primary data source is four to six in-depth interviews with individual teachers (about 40-90 minutes for each interview). The interviews are complemented by extensive classroom observations of individual teachers' teaching SSI and by document analysis (including teaching materials, rubrics, student group projects and journals, etc.). There are two major findings. First, the teachers' deeper values and ideals are a source of larger inspiration that plays a significant role in changing their teaching practice. This inspiration may involve higher aspects (e.g., deep concern for students' development, unselfishness, caring, etc.) and commitment. Their teaching represents an integration of their personal experiences, values, concerns, and worldviews, which forms a larger inspiration for teaching. Teaching SSI is a part of this larger process. Second, the current curriculum reforms (STS, SSI, and NOS) only suggest theoretical ideals and do not effectively touch teachers' deeper values and ideals. Basically, the teachers are doing what they

  11. Introduction. Progress in Earth science and climate studies.

    Science.gov (United States)

    Thompson, J Michael T

    2008-12-28

    In this introductory paper, I review the 'visions of the future' articles prepared by top young scientists for the second of the two Christmas 2008 Triennial Issues of Phil. Trans. R. Soc.A, devoted respectively to astronomy and Earth science. Topics covered in the Earth science issue include: trace gases in the atmosphere; dynamics of the Antarctic circumpolar current; a study of the boundary between the Earth's rocky mantle and its iron core; and two studies of volcanoes and their plumes. A final section devoted to ecology and climate covers: the mathematical modelling of plant-soil interactions; the effects of the boreal forests on the Earth's climate; the role of the past palaeoclimate in testing and calibrating today's numerical climate models; and the evaluation of these models including the quantification of their uncertainties.

  12. Practice Theory and Pragmatism in Science & Technology Studies

    DEFF Research Database (Denmark)

    Buch, Anders

    2015-01-01

    begin by an introduction to some of the proponents of practice theory and of pragmatism. Regarding the latter, I primarily present work by Dewey because this is what I am most familiar with. Although I recognize that practice theory and pragmatism differ on fundamental philosophical issues in relation...... to the normative evaluation of action, I show that the two intellectual traditions have much in common when it comes to what they do to STS studies. After this introduction to practice theory, my paper will proceed in the following steps. Firstly, I will briefly survey practice theoretical and pragmatist......Science & Technology Studies (STS) and social science has made a turn, a ‘practice turn’, and the notion ‘practice theory’ has made its way into the field of STS. But it is notable that proponents of this turn and theory rarely mention American pragmatism as a source of inspiration or refer...

  13. Study on the radiation effect of plastic syringe materials

    International Nuclear Information System (INIS)

    Byun, H.C.; Yun, B.M.; Kim, K.Y.; Kong, Y.K.; Park, H.Y.

    1983-01-01

    From the viewpoint of gammasterilization, the defects of domestic polypropylene as the syringe material are to get worse the mechanical properties and discoloration by irradiation. Therefore, the domestic polystyrene (GPPS 150) were inspected to use as substitute for the polypropylene. The gel point of the polystyrene was about 100Mrad and none momentous change of the mechanical properties were appeared until the dose reached to the point. Above the point, as the crosslinking reaction proceed both strength of tensile and impact were increased with discoloration. No significant problem was also found in the water extract test and chemical resistance test. In addition to the pure polystyrene, the copolymer of butadiene (HIPS 425) and the blend material of polypropylene were also inspected for the purpose and almost same results were obtained in the radiation irradiation. From the above result, it is considered that polystyrene and the copolymer and the blend mentioned above are available for the medical plastics which would be sterilized by gamma-radiation. (Author)

  14. Study on modification of radiation effects in mammalian fetuses

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kiyoto; Kawamata, Akitoshi; Goto, Toshifumi (Asahi Univ., Hozumi, Gifu (Japan). School of Dentistry) (and others)

    1990-10-01

    In searches for the potential application of mouse whole-embryo culture, combined effects of x radiation and cadmium or hyperthermia were examined with cultures of 8-day and 11-day mouse embryos. Combination of x radiation and cadmium had synergistic action on both in vitro and in vivo teratogenesis of mouse embryos. When irradiation was given 30 minutes before and after the administration of cadmium in 11-day mouse embryos, interaction factor values for cleft palate were 8.53 and 9.09, respectively. This revealed that the order of giving radiation and cadmium was independent of synergistic action. When low doses of radiation was combined with non-teratogenic hyperthermia, synergistic action occurred in vitro. This was more noticeable when combined with lower doses of x radiation. Low doses of x radiation are of great concern to human embryos or fetuses who may sustain potential exposures to them. (N.K.) 96 refs.

  15. ESR studies of the radiation effects on polystyrene

    International Nuclear Information System (INIS)

    Garrett, R.W.; O'Donnell, J.H.; Pomery, P.J.

    1976-01-01

    The aim of this work was to investigate the polystyrene system (both pure and commercial samples) to elucidate the type and percentage of each paramagnetic species upon exposure to various irradiation doses. The size of dose plays a vital role in the type of spectra obtained. Upon irradiation in vacuo, polystyrene displays ESR spectra which are basically triplet in character but the line spacing and intensities of components are observed to depend on the magnitude of the irradiation dose. G value for the total radicals present and for the individual species present as a function of dose have been obtained. The relative concentration of each paramagnetic species has been determined through computer simulation of the observed ESR spectra. The relative stability of the different species with respect to temperature is discussed. The results for deuterated polystyrene is used to support those obtained for the unsubstituted polystyrene system. (author)

  16. Experimental studies on radiation effects under high pressure oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Fujimura, E [Osaka Univ. (Japan). School of Dentistry

    1974-06-01

    The effect of oxygen tension on the radiosensitivity of tumor cells is well known, but its clinical application for radiotherapy is not yet established. Rabbits with V x 2 carcinoma in the maxilla were irradiated by /sup 60/Co under high pressure oxygen (experimental group), and compared with those treated in air (control group). For the purpose of examining the clinical effects of high pressure oxygen, an experiment was made in vivo. The following items were compared respectively: a) Tumor regression effect b) Tumor clearance rate c) Survival days d) Half size reduction time e) Inhibition of DNA synthesis in the tumor tissue. Results obtained were as follows: a) 56 per cent of animals showed tumor regression in the experimental group, whereas it occured 26 per cent in the control group. b) 53 per cent of animals showed tumor disappearance in the experimental group, while it was observed only in 13 per cent in the control group. c) Only 2 of 30 rabbits irradiated in air survived over 180 days, whereas 11 of 30 rabbits survived meanwhile in the group irradiated under high pressure oxygen. d) About 11 days were necessary to reduce the tumor size by half after irradiation in the group under high pressure oxygen, while it took 17 days in the group treated in normal air. e) DNA synthesis was inhibited more prominently in the group irradiated under high pressure oxygen in normal air.

  17. Study of the Gamma Radiation Effect on Tannins Samples

    International Nuclear Information System (INIS)

    Coto Hernandez, I.; Barroso Solares, S.; Martinez Luzardo, F.; Guzman Martinez, F.; Diaz Rizo, O.; Arado Lopez, J.O.; Santana Romero, J.L.; Baeza Fonte, A.; Rapado Paneque, M.; Garcia, F.

    2011-01-01

    Vegetable tannins are polyphenolic substances of different chemical mixtures, in correspondence with the characteristics of groups of polyphenols. Taking into consideration its composition, we can find different types of flavonoids, mainly in the so-called condensed tannins. In general, many applications have been explored, including the medical ones, due to their proven biological activity as antiviral, antibacterial and others characteristics derived from their reactions with metal ions and amino acids of the protein components. Therefore it is promising to examine the effects of gamma radiation on the structure of tannin, looking for the possible modification of its biological activity. To this end, samples of tannins are irradiated at different doses (maximum dose 35 kGy) with the use of a Cobalt-60 irradiator. Scanning Electron Microscopy (SEM) permitted to characterize the samples in morphology and composition. The changes were analyzed by using infrared spectroscopy Fourier transform (FT-IR) and High Resolution Liquid Chromatography (HPLC). At the end we discuss the implication of the results for a dosage range above 5 kGy. (Author)

  18. Study of a model for gamma radiation effects on chlorella

    International Nuclear Information System (INIS)

    Delforge, Jacques; Fabre, Henri; CEA Centre d'Etudes Nucleaires de Grenoble, 38

    1977-01-01

    The experimental data obtained by 60 Co γ irradiation of chlorella are especially interesting because they show a dose rate effect (change in the survival curve plotted versus dose as the dose rate varies) and a change in the survival fraction as a function of the time separating the end of irradiation and the starting of culture. The radiobiological models published until now are not able to illustrate all these experimental phenomena. An attempt is made here to find a model within the scope of P. DELATTRE's transformation system theory. The use of this precise theoretical framework enables to propose an experimental procedure which offers no special practical difficulty but leads to much more abundant information than the standard procedures. The model obtained reveals the existence of at least three different states amongst chlorella still able to multiply, and only one state amongst those temporarily deprived of their multiplying capacity. It shows the possibility of internal restorations in the elements still capable of multiplying, but also confirms the existence of non-lethal but irreparable lesions [fr

  19. Study on modification of radiation effects in mammalian fetuses

    International Nuclear Information System (INIS)

    Nakajima, Kiyoto; Kawamata, Akitoshi; Goto, Toshifumi

    1990-01-01

    In searches for the potential application of mouse whole-embryo culture, combined effects of x radiation and cadmium or hyperthermia were examined with cultures of 8-day and 11-day mouse embryos. Combination of x radiation and cadmium had synergistic action on both in vitro and in vivo teratogenesis of mouse embryos. When irradiation was given 30 minutes before and after the administration of cadmium in 11-day mouse embryos, interaction factor values for cleft palate were 8.53 and 9.09, respectively. This revealed that the order of giving radiation and cadmium was independent of synergistic action. When low doses of radiation was combined with non-teratogenic hyperthermia, synergistic action occurred in vitro. This was more noticeable when combined with lower doses of x radiation. Low doses of x radiation are of great concern to human embryos or fetuses who may sustain potential exposures to them. (N.K.) 96 refs

  20. Electron microscopy study of radiation effects in boron carbide

    International Nuclear Information System (INIS)

    Stoto, T.

    1987-03-01

    Boron carbide is a disordered non-stoechiometric material with a strongly microtwinned polycristallyne microstructure. This ceramic is among the candidate materials for the first wall coating in fusion reactor and is used as a neutron absorber in the control rods of fast breeder reactors. The present work deals with the nature of radiation damage in this solid. Because of helium internal production, neutron irradiated boron carbide is affected by swelling and by a strong microcracking which can break up a pellet in fine powder. These processes are rather intensitive to the irradiation parameters (temperature, flux and even neutron spectrum). Transmission electron microscopy of samples irradiated by the fast neutrons of a reactor, the electrons of a high voltage electron microscope and of samples implanted with helium ions was used to understand the respective roles of helium and point defects in the processes of swelling and microcracking. The design of an irradiation chamber for helium implantation at controlled temperature from 600 to 1700 0 C was an important technical part of this work [fr

  1. Study of abscopal radiation effects on multicellular organisms

    International Nuclear Information System (INIS)

    Ludwig, F.

    1958-01-01

    Amongst the lesions brought about by total body irradiation, two basically different types can be distinguished: those appearing in the area which has absorbed radiant energy and those emerging in areas remote from the irradiated tissues (abscopal effects). The abscopal effects are produced by toxic tissue breakdown products, which are removed by the bloodstream and interfere with particularly sensitive structures (radiotoxins). The radiotoxins mobilize other biologically active substances, interfering with the same tissues which may display abscopal effects. This is well established for the hormones of the adrenal cortex. Furthermore, important fractions of the radiotoxins are neutralized by the reticuloendothelial system. Temporary blockade of this system enhances the efficiency of radiotoxins and greatly increases mortality of the irradiated animals. One can therefore conclude that the reticuloendothelial system affords a natural defense against an essential reaction of total body irradiation: the effect of the radiotoxins. (author) [fr

  2. Model study of radiation effects on the gastrointestinal cell system

    International Nuclear Information System (INIS)

    Kicherer, G.

    1983-03-01

    Since it is now possible to calculate the radiation fields used for medicinal purposes by means of radiation transport programs it was started to determine with mathematical models of radioeffects not only the physical effects or irradiation, but also the resulting biological radioresponses. This supplementary biologic information is not only of large general importance, but particularly valuable for the medicinal application of the biologically highly effective neutron radiation. With support by the Institute for Medicinal Radiophysics and Radiobiology of Essen University Hospital, and of two biomathematical working groups of Ulm University and Cologne University Hospital, who are experienced in the field of establishing mathematical models of the hematogenic cellular system, we developed out of experimental fundamental findings a cellkinetic, kybernetic model of the intestinal mucosa, which is highly sensitive to radiation. With this newly established model we succeeded for the first time in simulating comprehensively and quantitatively the time-dependent acute radioresponse of such a radiosensitive cellular system. For the first time we successfully used the computer simulation languages DARE-P and GASP, which are principally employed for solving problems in automatic control technology, and set up a radioresponse model. (orig.) [de

  3. Understanding understanding in secondary school science: An interpretive study

    Science.gov (United States)

    O'Neill, Maureen Gail

    This study investigated the teaching of secondary school science with an emphasis on promoting student understanding. In particular, I focused on two research questions: What are the possible meanings of teaching for understanding? And, how might one teach secondary school science for understanding? After semi-structured interviews were conducted with 13 secondary school science teachers, grounded theory methodology was used to interpret the data. As a result of the selective coding process, I was able to identify 14 connected components of teaching for understanding (TfU). The process of TfU involves: puzzle-solving, a specific pedagogy and a conscious decision. The teacher must be a reflective practitioner who has some knowledge of the facets of understanding. The teacher comes to a critical incident or crisis in his or her pedagogy and adopts a mindset which highlights TfU as a personal problematic. Teachers operate with student-centred rather than teacher-centred metaphors. TfU requires a firm belief in and passion for the process, a positive attitude and excellent pedagogical content knowledge. It hinges on a performance view of understanding and demands risk-taking in the science classroom. Abstracting these ideas to a theory led me to the notion of Purposive Teaching . In their purposive-driven role as pedagogues, these teachers have placed TfU at the core of their daily practice. Constraints and challenges facing TfU as well as implications of the findings are discussed. Keywords. science teaching, teaching for understanding, purposive teaching, constructivism, understanding, pedagogy, pedagogical content knowledge, memorization, meaningful learning, reflective practice.

  4. Science Study For A Low Cost Upper Atmosphere Sounder (LOCUS)

    Science.gov (United States)

    Gerber, D.; Swinyard, B. M.; Ellison, B. N.; Siddans, R.; Kerridge, B. J.; Plane, J. M. C.; Feng, W.

    2013-12-01

    We present the findings of an initial science study to define the spectral bands for the proposed Mesosphere / Lower Thermosphere (MLT) sounder LOCUS. The LOCUS mission (Fig 1) uses disruptive technologies to make key MLT species detectable globally by satellite remote sensing for the first time. This presentation summarises the technological and scientific foundation on which the current 4-band Terahertz (THz) and sub- millimetre wave (SMW) instrument configuration was conceived.

  5. Managing change : Case study: HAMK University of Applied Sciences, Valkeakoski

    OpenAIRE

    Chau Thi Tra, Mi

    2012-01-01

    In response to changes imposed by the Finnish government on the Univer-sities of Applied Sciences system in the near future, HAMK has proactive-ly adopted several programmes to prepare for future challenges and rein-force the organization’s competitiveness. However, organizational change has never been an easy, straightforward issue and how to manage change effectively has become an interest to the organization. The study aims at providing suggestions for a more successful change im-pleme...

  6. Radiation effects in x-irradiated hydroxy compounds

    International Nuclear Information System (INIS)

    Budzinski, E.E.; Potter, W.R.; Box, H.C.

    1980-01-01

    Radiation effects are compared in single crystals of xylitol, sorbitol, and dulcitol x-irradiated at 4.2 0 K. In xylitol and dulcitol, but not in sorbitol, a primary oxidation product is identified as an alkoxy radical. ENDOR measurements detected three proton hyperfine couplings associated with the alkoxy ESR absorption, one of which is attributed to a proton three bond lengths removed from the seat of unpaired spin density. Intermolecular trapping of electrons is observed in all three crystals. ENDOR measurements were made of the hyperfine couplings between the trapped electron and the hydroxy protons forming the trap

  7. A preliminary assessment of radiation effects on American Flagfish

    Energy Technology Data Exchange (ETDEWEB)

    Tzivaki, M.; Waller, E., E-mail: margarita.tzivaki@uoit.ca [University of Ontario Institute of Technology, Oshawa, ON (Canada)

    2015-07-01

    In order to add to the knowledge base of radiation effects on non-human biota, it is important to define benchmark values for different species. An experimental set-up was designed to investigate effects from irradiation with Cs-137 to American Flagfish. Preliminary experiments to assess the suitability of the methodology were conducted by exposing Flagfish eggs to 44 h of ionizing radiation. The subsequent observation of the developing fry showed no effect on hatching. However, the mortality and observed vertebral malformations were increased with increasing absorbed dose which is suspected to be a result of developmental defects in the embryonic stage. (author)

  8. Investigation of ionizing radiation effect on albumin aqueous solutions

    International Nuclear Information System (INIS)

    Sizikov, A.M.; Adeeva, L.N.; Ogryzkova, I.F.

    1986-01-01

    Gamma radiation effect on 0.1-0.5%-albumin aqueous solutions has been investigated; variations of viscosity and optical density of solutions at pH medium different values and completeness of protein separation owing to radiation coagulation have been determined. It is shown that due to radiation coagulation it is possible to quantitatively separate albumin from irradiated aqueous solutions. The albumin coagulation is caused by OH radicals the action of which on albumin macromolecules results in destruction of intramolecular bonds and albumin conformation transformations

  9. Radiation Effects in III-V Nanowire Devices

    Science.gov (United States)

    2016-09-01

    fabrication of an in-plane nanowire (NW) GaAs metal-oxide-semiconductor field- effect transistor (MOSFET) by focused -ion beam (FIB) etching and chemical...8725 John J. Kingman Road, MS 6201 Fort Belvoir, VA 22060-6201 T E C H N IC A L R E P O R T DTRA-TR-16-94 Radiation Effects in III-V...5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING / MONITORING AGENCY

  10. Biosynthesis of proteins and radiation effects in cells

    International Nuclear Information System (INIS)

    Kolomiets, K.D.

    1982-01-01

    Critical analysis of nowadays literature and own experimental data on importance of biosynthesis of proteins, their modification and functional activity in forming radiation effects in irradiated cells is given. A special place in the development of radiation injury of cellular structures and in reduction processes is allocated to molecular recognition. The data on the role of protein synthesis and molecular recognition in the reduction of main biological cell chromatin system are presented. The dependence of postradiation changes in the cell on structural and functional chromatin state is considered

  11. Research of pulse gamma ray radiation effect on microcontroller system

    International Nuclear Information System (INIS)

    Yang Shanchao; Ma Qiang; Jin Xiaoming; Li Ruibin; Lin Dongsheng; Chen Wei; Liu Yan

    2012-01-01

    An experimental result of power chip LM7805 and microcontroller EE80C196KC20 based on the EE80C196KC20 testing system was presented. The pulse gamma ray radiation effect was investigated using 'Qiangguang-Ⅰ' accelerator. Latchup threshold of the microcontroller was obtained, and the relationship of supply current and I/O output with the transient dose rate was observed. The result shows that the restrainability of power chip on pulse gamma ray radiation induces microcontroller latchup effect. (authors)

  12. Radiation effects on time-dependent deformation: Creep and growth

    International Nuclear Information System (INIS)

    Simonen, E.P.

    1989-03-01

    Observations of irradiation creep strain as well as irradiation growth strain and related microstructures are reviewed and compared to mechanisms for radiation effects on time-dependent deformation. Composition, microstructure, stress and temperature affect irradiation creep less than thermal creep. Irradiation creep rates can often dominate thermal creep rates, particularly at low temperatures and low stresses. Irradiation creep mechanisms are classified in two general categories: (1) stress-induced preferential absorption and (2) climb-glide. In the former, creep results from dislocation climb, whereas in the latter, creep results from dislocation glide. The effects of irradiation creep on failure modes in nuclear environments are discussed. 53 refs., 18 figs., 1 tab

  13. Transient radiation effects in GaAs semiconductor devices

    International Nuclear Information System (INIS)

    Chang, J.Y.; Stauber, M.; Ezzeddine, A.; Howard, J.W.; Constantine, A.G.; Becker, M.; Block, R.C.

    1988-01-01

    This paper describes an ongoing program to identify the response of GaAs devices to intense pulses of ionizing radiation. The program consists of experimental measurements at the Rensselaer Polytechnic Institute's RPI electron linear accelerator (Linac) on generic GaAs devices built by Grumman Tachonics Corporation and the analysis of these results through computer simulation with the circuit model code SPICE (including radiation effects incorporated in the variations TRISPICE and TRIGSPICE and the device model code PISCES IIB). The objective of this program is the observation of the basic response phenomena and the development of accurate simulation tools so that results of Linac irradiations tests can be understood and predicted

  14. Study of the rice husk ash utilization as filler polypropylene matrix and ionization radiation effect on this composite; Estudos da utilizacao da cinza de casca de arroz como carga em matriz de polipropileno e do efeito da radiacao ionizante sobre este composito

    Energy Technology Data Exchange (ETDEWEB)

    Alfaro, Eduardo de Faria

    2010-07-01

    In the first step of this work, it was evaluated the possibility of using rice husk ash as a filler in polypropylene (PP) making a comparison with talc which is the most used mineral filler in polymers. This comparison was made by using polypropylene with 20% rice husk ash as well as polypropylene with 20% talc measuring their properties. Despite the properties of the PP with 20% rice husk ash decreased compared with the composite of polypropylene with 20% talc it can be said that the rice husk ash can be used as filler for or other utilization less noble of PP . This way it is being given a destination for this residue that it is disposable in the environment contributing to its preservation, moreover reducing the product cost. This work had also as an aim to study the ionizing radiation effect in the properties of these composites. It was used the coupling agent, maleic anhydride , to verify a best sample homogenization. According to the results it can be said that PP is a semicrystalline polymer, and so it has its morphology modified when exposed to the irradiation process. This fact is due to the scission mechanisms of the polymeric chains which it is in compliance to the literature. (author)

  15. The Normality of EU Sport Policy Studies: Disciplinary Locus in Political Science, Sport Science or Elsewhere?

    Directory of Open Access Journals (Sweden)

    Jacob Kornbeck

    2014-05-01

    Full Text Available The Normality of EU Sport Policy Studies: Disciplinary Locus in Political Science, Sport Science or Elsewhere? Mainstream European integration research has shown that research on the EU tends to follow the conjunctures of European integration itself. This realisation has led to some debate on which branch of political science – international relations or government – or indeed other academic disciplines is/are the most appropriate locus for such research. The paper takes these debates one step further by looking at the occurrence of ‘EU & sport’ studies within the wider field of EU studies. The main material used comes from the ECLAS database. Findings lead to a discussion of whether ‘EU & sport’ studies should rather be for EU specialists or for sport specialists and a plea for disciplinary normalisation whereby sport science would need to get more directly involved (without necessarily overwriting political science. Some ideas are added regarding the need for a mapping of Central & Eastern European scholarship. Normalita politických studií EU v oblasti sportu: místo v oborech politologie, sportovních vědách či jinde? Hlavní integrační proudy v evropském výzkumu dokumentují, že výzkum v EU má tendenci zkoumat evropskou integraci jako takovou. Toto poznání vedlo k diskusi, v kterém oboru politologie – mezinárodní vztahy či vláda – nebo i v jiných akademických disciplínách je nejvhodnější místo pro takový výzkum. Stať se pokouší posunout tyto diskuse o krok dále tím, že studie o „EU a sportu“ se posuzují v širším záběru EU studií. Hlavní informační zdroje pocházejí z databáze ECLAS. Naše zjištění vedou k diskusi o problematice „EU a sportu“ v tom smyslu, zda by tyto studie měly být spíše určeny odborníkům EU, nebo sportovním specialistům. Důležitá je otázka disciplinární začlenění této problematiky, s širším zapojením sportovních věd (aniž by

  16. NATURAL SCIENCE AT SCHOOL: MODERN APPROACHES TO THE DIFFERENTIATED STUDY

    Directory of Open Access Journals (Sweden)

    Dechtyarenko S.G.

    2015-08-01

    Full Text Available The article analyzes the possibility of differentiated study natural science at school on the basis of ecological educational process. Natural science is the science about nature as a single unity or totality of the natural sciences, which constituting a single unit. The main aim of the course is to develop student’s natural science competence through integrated mastering system knowledge about nature and man, the basics of environmental knowledge, ways of improving teaching and learning activities, development of value orientations in relation to the nature. There is strong need to review approaches to teaching nature science at schools, taking into account the general trend of greening of the educational process. The aim of the work is to analyze the possibility of practical application of modern approaches to differentiated teaching of the nature science at school greening within the educational process. In our view, the environmental component may be a basis to the formation and differentiated teaching in general. The environmental component of the educational sector has been aimed to the student’s environmental consciousness and compliance with rules of environmentally safe behavior in the environment. The learning of the integrated knowledge about nature and man can be submitted through the prism of action of the environmental factors according classic approach to their classification: abiotic, biotic and anthropogenic factors. In parallel, it is reasonable to raise the issues of practical importance as some natural objects and actions of each of these factors. The new degree of the studying of the environment has been provided by the beginning of the systematization of knowledge about natural objects and structure of the universe, by the formation of primary concepts about the relationship between the world of the living and inanimate nature, between organisms and between human activities and changes that has been occurred in the

  17. Student science publishing: an exploratory study of undergraduate science research journals and popular science magazines in the US and Europe

    Directory of Open Access Journals (Sweden)

    Mico Tatalovic

    2008-09-01

    Full Text Available Science magazines have an important role in disseminating scientific knowledge into the public sphere and in discussing the broader scope affected by scientific research such as technology, ethics and politics. Student-run science magazines afford opportunities for future scientists, communicators, politicians and others to practice communicating science. The ability to translate ‘scientese’ into a jargon-free discussion is rarely easy: it requires practice, and student magazines may provide good practice ground for undergraduate and graduate science students wishing to improve their communication skills.

  18. Life Sciences Division and Center for Human Genome Studies 1994

    Energy Technology Data Exchange (ETDEWEB)

    Cram, L.S.; Stafford, C. [comp.

    1995-09-01

    This report summarizes the research and development activities of the Los Alamos National Laboratory`s Life Sciences Division and the biological aspects of the Center for Human Genome Studies for the calendar year 1994. The technical portion of the report is divided into two parts, (1) selected research highlights and (2) research projects and accomplishments. The research highlights provide a more detailed description of a select set of projects. A technical description of all projects is presented in sufficient detail so that the informed reader will be able to assess the scope and significance of each project. Summaries useful to the casual reader desiring general information have been prepared by the group leaders and appear in each group overview. Investigators on the staff of the Life Sciences Division will be pleased to provide further information.

  19. Central Computer Science Concepts to Research-Based Teacher Training in Computer Science: An Experimental Study

    Science.gov (United States)

    Zendler, Andreas; Klaudt, Dieter

    2012-01-01

    The significance of computer science for economics and society is undisputed. In particular, computer science is acknowledged to play a key role in schools (e.g., by opening multiple career paths). The provision of effective computer science education in schools is dependent on teachers who are able to properly represent the discipline and whose…

  20. Understanding the Influence of Learners' Forethought on Their Use of Science Study Strategies in Postsecondary Science Learning

    Science.gov (United States)

    Dunn, Karee E.; Lo, Wen-Juo

    2015-11-01

    Understanding self-regulation in science learning is important for theorists and practitioners alike. However, very little has been done to explore and understand students' self-regulatory processes in postsecondary science courses. In this study, the influence of science efficacy, learning value, and goal orientation on the perceived use of science study strategies was explored using structural equation modeling. In addition, the study served to validate the first two stages of Zimmerman's cyclical model of self-regulation and to address the common methodological weakness in self-regulation research in which data are all collected at one point after the learning cycle is complete. Thus, data were collected across the learning cycle rather than asking students to reflect upon each construct after the learning cycle was complete. The findings supported the hypothesized model in which it was predicted that self-efficacy would significantly and positively influence students' perceived science strategy use, and the influence of students' valuation of science learning on science study strategies would be mediated by their learning goal orientation. The findings of the study are discussed and implications for undergraduate science instructors are proposed.

  1. Degrading radiation effects on properties of bromobutyl rubber compounds

    Energy Technology Data Exchange (ETDEWEB)

    Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Pozenato, Cristina A.; Lugao, Ademar B., E-mail: srscagliusi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The understanding of chemistry involved in degradation induced radiation is becoming more and more relevant in the re-use of polymeric materials, as well in beneficial radiation uses. Degrading radiation effects have been considered from viewpoint of controlled degradation for isoprene/isobutene in rubbers for recycling purposes. Bromobutyl rubber (BIIR) is an isobutylene/isoprene copolymer comprising 1.9 to 2.1% bromine and has a lot of applications including in tires air-chambers. In this work there were evaluated gamma-irradiation effects for re-use or recycling objectives in elastomeric bromobutyl compositions irradiated at 5, 15, 25, 50, 100,150 and 200 kGy. Mechanical properties, hardness and swelling were assessed in non-vulcanized and vulcanized rubber, non-irradiated and irradiated at different doses. The major gamma radiation effect in butyl rubber is the generation of free radicals along changes in mechanical properties. Irradiation effects in bromobutyl rubber compounds were comprehensively investigated, demonstrated and discussed. (author)

  2. Degrading radiation effects on properties of bromobutyl rubber compounds

    International Nuclear Information System (INIS)

    Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Pozenato, Cristina A.; Lugao, Ademar B.

    2013-01-01

    The understanding of chemistry involved in degradation induced radiation is becoming more and more relevant in the re-use of polymeric materials, as well in beneficial radiation uses. Degrading radiation effects have been considered from viewpoint of controlled degradation for isoprene/isobutene in rubbers for recycling purposes. Bromobutyl rubber (BIIR) is an isobutylene/isoprene copolymer comprising 1.9 to 2.1% bromine and has a lot of applications including in tires air-chambers. In this work there were evaluated gamma-irradiation effects for re-use or recycling objectives in elastomeric bromobutyl compositions irradiated at 5, 15, 25, 50, 100,150 and 200 kGy. Mechanical properties, hardness and swelling were assessed in non-vulcanized and vulcanized rubber, non-irradiated and irradiated at different doses. The major gamma radiation effect in butyl rubber is the generation of free radicals along changes in mechanical properties. Irradiation effects in bromobutyl rubber compounds were comprehensively investigated, demonstrated and discussed. (author)

  3. science

    International Development Research Centre (IDRC) Digital Library (Canada)

    David Spurgeon

    Give us the tools: science and technology for development. Ottawa, ...... altered technical rela- tionships among the factors used in the process of production, and the en- .... to ourselves only the rights of audit and periodic substantive review." If a ...... and destroying scarce water reserves, recreational areas and a generally.

  4. Liberal Studies in Science--A Successful Experiment

    Science.gov (United States)

    Jevons, F. R.

    1970-01-01

    Describes the job placement success experienced by graduates of the Science Greats Course at the University of Manchester. Discusses the course content which centers on the social relations of science. Since nearly half the course involves science content, the author discusses the science background necessary for enrollees. Presents a personal…

  5. Application of AMS radiocarbon in earth system science studies

    International Nuclear Information System (INIS)

    Kang, Dong Jin; Park, Mi Kyung; Kim, Kyung Ryul

    2001-01-01

    Radiocarbon, a cosmic ray-produced isotope, is one of the most important tracers in Earth system sciences. The strong involvement of carbon in the biosphere and its half life of 5720 years are reflected in appropriate applications in archeology, as well as in the Earth system sciences. Radiocarbon dating had an important turning point in 1977 with the discovery that mass spectrometry with tandem acceleration could be used to measure C-14. This new technique, known as AMS or accelerator mass spectrometry reduced the required sample size to the order of mg, three orders of magnitude smaller than for conventional techniques, thus opening the range of applicability of C-14 studies to a much wider range of samples. However, the application has been complicated by two major activities of human beings on a global scale: the extensive usage of fossil fuel since the industrial revolution and nuclear testing in the atmosphere, which have influenced the natural balance of radiocarbon in the atmosphere. However, the separation of bomb-produced carbon from natural background carbon has produced a very fruitful understanding of the global carbon cycle and the conveyor belt system in the ocean, which will be essential for understanding global environmental problems, such as global warming, in the coming century. Carbon cycle studies in Korea have been made since the early 1990s. The studies include monitoring of CO 2 concentrations in the atmosphere, stable isotope studies, and carbon cycle studies in the sea around Korea. The opening of ths AMS facility at Seoul National University (SNU) will enhance carbon studies in Earth system sciences greatly in the future

  6. An Exploratory Case Study of Olympiad Students' Attitudes towards and Passion for Science

    Science.gov (United States)

    Oliver, Mary; Venville, Grady

    2011-01-01

    Much is known about high school students' attitudes towards science but there is almost no research on what passion for science might look like and how it might be manifested. This exploratory case study took advantage of a unique group of highly gifted science students participating in the Australian Science Olympiad (N = 69) to explore their…

  7. Bioinformatics in High School Biology Curricula: A Study of State Science Standards

    Science.gov (United States)

    Wefer, Stephen H.; Sheppard, Keith

    2008-01-01

    The proliferation of bioinformatics in modern biology marks a modern revolution in science that promises to influence science education at all levels. This study analyzed secondary school science standards of 49 U.S. states (Iowa has no science framework) and the District of Columbia for content related to bioinformatics. The bioinformatics…

  8. Case Study: Teaching Nature of Science through Scientific Models--The Geocentric vs. Heliocentric Cosmology

    Science.gov (United States)

    Price, Matthew; Rogers, Michael

    2016-01-01

    In the nonmajor science classroom, case studies--when used as learning tools--should help students build the necessary framework to understand the nature of science. For most students, the nonmajor science course (in this case, Astronomy 101) may be the last time that they interact with science in a formal learning setting. A National Science…

  9. Predicting Nonauditory Adverse Radiation Effects Following Radiosurgery for Vestibular Schwannoma: A Volume and Dosimetric Analysis

    International Nuclear Information System (INIS)

    Hayhurst, Caroline; Monsalves, Eric; Bernstein, Mark; Gentili, Fred; Heydarian, Mostafa; Tsao, May; Schwartz, Michael; Prooijen, Monique van; Millar, Barbara-Ann; Ménard, Cynthia; Kulkarni, Abhaya V.; Laperriere, Norm; Zadeh, Gelareh

    2012-01-01

    Purpose: To define clinical and dosimetric predictors of nonauditory adverse radiation effects after radiosurgery for vestibular schwannoma treated with a 12 Gy prescription dose. Methods: We retrospectively reviewed our experience of vestibular schwannoma patients treated between September 2005 and December 2009. Two hundred patients were treated at a 12 Gy prescription dose; 80 had complete clinical and radiological follow-up for at least 24 months (median, 28.5 months). All treatment plans were reviewed for target volume and dosimetry characteristics; gradient index; homogeneity index, defined as the maximum dose in the treatment volume divided by the prescription dose; conformity index; brainstem; and trigeminal nerve dose. All adverse radiation effects (ARE) were recorded. Because the intent of our study was to focus on the nonauditory adverse effects, hearing outcome was not evaluated in this study. Results: Twenty-seven (33.8%) patients developed ARE, 5 (6%) developed hydrocephalus, 10 (12.5%) reported new ataxia, 17 (21%) developed trigeminal dysfunction, 3 (3.75%) had facial weakness, and 1 patient developed hemifacial spasm. The development of edema within the pons was significantly associated with ARE (p = 0.001). On multivariate analysis, only target volume is a significant predictor of ARE (p = 0.001). There is a target volume threshold of 5 cm3, above which ARE are more likely. The treatment plan dosimetric characteristics are not associated with ARE, although the maximum dose to the 5th nerve is a significant predictor of trigeminal dysfunction, with a threshold of 9 Gy. The overall 2-year tumor control rate was 96%. Conclusions: Target volume is the most important predictor of adverse radiation effects, and we identified the significant treatment volume threshold to be 5 cm3. We also established through our series that the maximum tolerable dose to the 5th nerve is 9 Gy.

  10. Predicting Nonauditory Adverse Radiation Effects Following Radiosurgery for Vestibular Schwannoma: A Volume and Dosimetric Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hayhurst, Caroline; Monsalves, Eric; Bernstein, Mark; Gentili, Fred [Gamma Knife Unit, Division of Neurosurgery, University Health Network, Toronto (Canada); Heydarian, Mostafa; Tsao, May [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); Schwartz, Michael [Radiation Oncology Program and Division of Neurosurgery, Sunnybrook Hospital, Toronto (Canada); Prooijen, Monique van [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); Millar, Barbara-Ann; Menard, Cynthia [Radiation Oncology Program, Princess Margaret Hospital, Toronto (Canada); Kulkarni, Abhaya V. [Division of Neurosurgery, Hospital for Sick Children, University of Toronto (Canada); Laperriere, Norm [Radiation Oncology Program, Princess Margaret Hospital, Toronto (Canada); Zadeh, Gelareh, E-mail: Gelareh.Zadeh@uhn.on.ca [Gamma Knife Unit, Division of Neurosurgery, University Health Network, Toronto (Canada)

    2012-04-01

    Purpose: To define clinical and dosimetric predictors of nonauditory adverse radiation effects after radiosurgery for vestibular schwannoma treated with a 12 Gy prescription dose. Methods: We retrospectively reviewed our experience of vestibular schwannoma patients treated between September 2005 and December 2009. Two hundred patients were treated at a 12 Gy prescription dose; 80 had complete clinical and radiological follow-up for at least 24 months (median, 28.5 months). All treatment plans were reviewed for target volume and dosimetry characteristics; gradient index; homogeneity index, defined as the maximum dose in the treatment volume divided by the prescription dose; conformity index; brainstem; and trigeminal nerve dose. All adverse radiation effects (ARE) were recorded. Because the intent of our study was to focus on the nonauditory adverse effects, hearing outcome was not evaluated in this study. Results: Twenty-seven (33.8%) patients developed ARE, 5 (6%) developed hydrocephalus, 10 (12.5%) reported new ataxia, 17 (21%) developed trigeminal dysfunction, 3 (3.75%) had facial weakness, and 1 patient developed hemifacial spasm. The development of edema within the pons was significantly associated with ARE (p = 0.001). On multivariate analysis, only target volume is a significant predictor of ARE (p = 0.001). There is a target volume threshold of 5 cm3, above which ARE are more likely. The treatment plan dosimetric characteristics are not associated with ARE, although the maximum dose to the 5th nerve is a significant predictor of trigeminal dysfunction, with a threshold of 9 Gy. The overall 2-year tumor control rate was 96%. Conclusions: Target volume is the most important predictor of adverse radiation effects, and we identified the significant treatment volume threshold to be 5 cm3. We also established through our series that the maximum tolerable dose to the 5th nerve is 9 Gy.

  11. How Models Simulate the Radiative Effect in the Transition Zone of the Aerosol-Cloud Continuum

    Science.gov (United States)

    Calbo Angrill, J.; González, J. A.; Long, C. N.; McComiskey, A. C.

    2017-12-01

    Several studies have pointed towards dealing with clouds and aerosols as two manifestations of what is essentially the same physical phenomenon: a suspension of tiny particles in the air. Although the two extreme cases (i.e., pure aerosol and well-defined cloud) are easily distinguished, and obviously produce different radiative effects, there are many situations in the transition (or "twilight") zone. In a recent paper [Calbó et al., Atmos. Res. 2017, j.atmosres.2017.06.010], the authors of the current communication estimated that about 10% of time there might be a suspension of particles in the air that is difficult to distinguish as either cloud or aerosol. Radiative transfer models, however, simulate the effect of clouds and aerosols with different modules, routines, or parameterizations. In this study, we apply a sensitivity analysis approach to assess the ability of two radiative transfer models (SBDART and RRTM) in simulating the radiative effect of a suspension of particles with characteristics in the boundary between cloud and aerosol. We simulate this kind of suspension either in "cloud mode" or in "aerosol mode" and setting different values of optical depth, droplet size, water path, aerosol type, cloud height, etc. Irradiances both for solar and infrared bands are studied, both at ground level and at the top of the atmosphere, and all analyses are repeated for different solar zenith angles. We obtain that (a) water clouds and ice clouds have similar radiative effects if they have the same optical depth; (b) the spread of effects regarding different aerosol type/aerosol characteristics is remarkable; (c) radiative effects of an aerosol layer and of a cloud layer are different, even if they have similar optical depth; (d) for a given effect on the diffuse component, the effect on the direct component is usually greater (more extinction of direct beam) by aerosols than by clouds; (e) radiative transfer models are somewhat limited when simulating the

  12. A Comparative Study of the Quality of Teaching Learning Process at Post Graduate Level in the Faculty of Science and Social Science

    Science.gov (United States)

    Shahzadi, Uzma; Shaheen, Gulnaz; Shah, Ashfaque Ahmed

    2012-01-01

    The study was intended to compare the quality of teaching learning process in the faculty of social science and science at University of Sargodha. This study was descriptive and quantitative in nature. The objectives of the study were to compare the quality of teaching learning process in the faculty of social science and science at University of…

  13. Contested Domains of Science and Science Learning in Contemporary Native American Communities: Three Case Studies from a National Science Foundation grant titled, "Archaeology Pathways for Native Learners"

    Science.gov (United States)

    Parent, Nancy Brossard

    This dissertation provides a critical analysis of three informal science education partnerships that resulted from a 2003-2006 National Science Foundation grant titled, "Archaeology Pathways for Native Learners" (ESI-0307858), hosted by the Mashantucket Pequot Museum and Research Center. This dissertation is designed to contribute to understandings of learning processes that occur within and at the intersection of diverse worldviews and knowledge systems, by drawing upon experiences derived from three disparate contexts: 1) The Navajo Nation Museum in Window Rock, Arizona; 2) The A:shiwi A:wan Museum and Heritage Center on the Zuni Reservation in Zuni, New Mexico; and 3) Science learning camps at the Mashantucket Pequot Museum and Research Center for Native youth of southern New England. While informal science education is increasingly moving toward decolonizing and cross-cutting institutional boundaries of learning through critical thinking and real-world applications, the construction of "science" (even within diverse contexts) continues to be framed within a homogenous, predominantly Euro-American perspective. This study analyzes the language of Western science employed in these partnerships, with particular attention to the use of Western/Native binaries that shape perceptions of Native peoples and communities, real or imagined. Connections are drawn to broader nation-state interests in education, science, and the global economy. The role of educational evaluation in these case studies is also critically analyzed, by questioning the ways in which it is constructed, conducted, and evaluated for the purposes of informing future projects and subsequent funding. This study unpacks problems of the dominant language of "expert" knowledge embedded in Western science discourse, and highlights the possibilities of indigenous knowledge systems that can inform Western science frameworks of education and evaluation. Ultimately, this study suggests that research

  14. Global radiative effects of solid fuel cookstove aerosol emissions

    Science.gov (United States)

    Huang, Yaoxian; Unger, Nadine; Storelvmo, Trude; Harper, Kandice; Zheng, Yiqi; Heyes, Chris

    2018-04-01

    We apply the NCAR CAM5-Chem global aerosol-climate model to quantify the net global radiative effects of black and organic carbon aerosols from global and Indian solid fuel cookstove emissions for the year 2010. Our assessment accounts for the direct radiative effects, changes to cloud albedo and lifetime (aerosol indirect effect, AIE), impacts on clouds via the vertical temperature profile (semi-direct effect, SDE) and changes in the surface albedo of snow and ice (surface albedo effect). In addition, we provide the first estimate of household solid fuel black carbon emission effects on ice clouds. Anthropogenic emissions are from the IIASA GAINS ECLIPSE V5a inventory. A global dataset of black carbon (BC) and organic aerosol (OA) measurements from surface sites and aerosol optical depth (AOD) from AERONET is used to evaluate the model skill. Compared with observations, the model successfully reproduces the spatial patterns of atmospheric BC and OA concentrations, and agrees with measurements to within a factor of 2. Globally, the simulated AOD agrees well with observations, with a normalized mean bias close to zero. However, the model tends to underestimate AOD over India and China by ˜ 19 ± 4 % but overestimate it over Africa by ˜ 25 ± 11 % (± represents modeled temporal standard deviations for n = 5 run years). Without BC serving as ice nuclei (IN), global and Indian solid fuel cookstove aerosol emissions have net global cooling radiative effects of -141 ± 4 mW m-2 and -12 ± 4 mW m-2, respectively (± represents modeled temporal standard deviations for n = 5 run years). The net radiative impacts are dominated by the AIE and SDE mechanisms, which originate from enhanced cloud condensation nuclei concentrations for the formation of liquid and mixed-phase clouds, and a suppression of convective transport of water vapor from the lower troposphere to the upper troposphere/lower stratosphere that in turn leads to reduced ice cloud formation. When BC is allowed

  15. Teaching Mathematical Modelling for Earth Sciences via Case Studies

    Science.gov (United States)

    Yang, Xin-She

    2010-05-01

    Mathematical modelling is becoming crucially important for earth sciences because the modelling of complex systems such as geological, geophysical and environmental processes requires mathematical analysis, numerical methods and computer programming. However, a substantial fraction of earth science undergraduates and graduates may not have sufficient skills in mathematical modelling, which is due to either limited mathematical training or lack of appropriate mathematical textbooks for self-study. In this paper, we described a detailed case-study-based approach for teaching mathematical modelling. We illustrate how essential mathematical skills can be developed for students with limited training in secondary mathematics so that they are confident in dealing with real-world mathematical modelling at university level. We have chosen various topics such as Airy isostasy, greenhouse effect, sedimentation and Stokes' flow,free-air and Bouguer gravity, Brownian motion, rain-drop dynamics, impact cratering, heat conduction and cooling of the lithosphere as case studies; and we use these step-by-step case studies to teach exponentials, logarithms, spherical geometry, basic calculus, complex numbers, Fourier transforms, ordinary differential equations, vectors and matrix algebra, partial differential equations, geostatistics and basic numeric methods. Implications for teaching university mathematics for earth scientists for tomorrow's classroom will also be discussed. Refereces 1) D. L. Turcotte and G. Schubert, Geodynamics, 2nd Edition, Cambridge University Press, (2002). 2) X. S. Yang, Introductory Mathematics for Earth Scientists, Dunedin Academic Press, (2009).

  16. Radiation effects on man health, environment, safety, security. Global Chernobyl mapping

    International Nuclear Information System (INIS)

    Bebeshko, V.; Bazyka, D.; Volovik, S.; Loganovsky, K.; Sushko, V.; Siedow, J.; Cohen, H.; Ginsburg, G.; Chao, N.; Chute, J.

    2007-01-01

    Complete text of publication follows. Objectives: Ionizing radiation is a primordial terrestrial and extraterrestrial background and archetypal environmental stress-factor for life origin, evolution, and existence. We all live in radiation world inevitably involving nuclear energy production, nuclear weapon, nuclear navy, radioactive waste, pertinent medical diagnostics and treatment, etc with connected certain probability of relevant accidents and terrorist attack, space and jet travels, high natural background radiation, etc - actual and potential sources of radiation exposures and effects. State-of- the art integral fundamental research on radiation effects on man health, environment, safety, and security (REMHESS) is nowadays paramount necessity and challenge. Methods and results: In given generalized conceptual framework unique 20 years Chernobyl multidimensional research and databases for radiation effects on man's all organism systems represent invaluable original basis and resources for mapping Chernobyl data and REMHESS challenge. Granted by DOE brand new Chernobyl Research and Service Project based on 'Sarcophagus-II' (Object 'Shelter') workers only one in radiation history baseline cohort, corresponding biorepository prospective dynamic data, integrated conceptual database system, and 'state of the art' 'omics' (genomics, proteomics, metabolomics) analysis is designed specifically for coherent addressing global REMHESS problems. In this connection 'Sarcophagus-II' is only one unique universal model. Conclusions: The fundamental goals of novel strategic Project and global Chernobyl mapping are to determine specific 'omics' signatures of radiation for man depending of exposure peculiarity to understand ultimate molecular mechanisms of radiation effects, gene environment interactions, etiology of organisms systems disorders and diseases, and to develop new biomarkers and countermeasures to protect man health in the framework of global REMHESS challenge

  17. Development and evaluation of a skin organ model for the analysis of radiation effects

    International Nuclear Information System (INIS)

    Meineke, V.; Mueller, K.; Ridi, R.; Cordes, N.; Beuningen, D. van; Koehn, F.M.; Ring, J.; Mayerhofer, A.

    2004-01-01

    Background and purpose: the reaction of tissues to ionizing radiation involves alterations in cell-cell and cell-matrix interactions mediated by cellular adhesion molecules. The aim of this study was to develop and evaluate an artificial skin organ model for the analysis of radiation effects. Material and methods: a human co-culture system consisting of the spontaneously immortalized keratinocyte cell line HaCaT and primary HDFa fibroblasts embedded into a collagen sponge was established. This skin organ model has been characterized and evaluated for its suitability for radiobiological investigations. For that purpose, expression of β 1 -integrin following irradiation was compared in the skin organ model and in HaCaT monolayer cells (FACScan and immunohistochemistry). Furthermore, the influence of ionizing radiation on DNA fragmentation was investigated in the skin organ model (TUNEL assay). Results: the novel skin organ model showed characteristics of human skin as demonstrated by cytokeratin and Ki-67 immunoreactivity and by electron microscopy. A single dose of 5 Gy X-irradiation induced an upregulation of β 1 -integrin expression both in the skin organ model and in HaCaT cells. Following irradiation, β 1 -integrin immunoreactivity was intensified in the upper layers of the epidermis equivalent whereas it was almost absent in the deeper layers. Additionally, irradiation of the skin organ model also caused a marked increase of DNA fragmentation. Conclusion: these results demonstrate that the novel skin organ model is suitable to investigate cellular radiation effects under three-dimensional conditions. This allows to investigate radiation effects which cannot be demonstrated in monolayer cell cultures. (orig.)

  18. Radiative budget and cloud radiative effect over the Atlantic from ship-based observations

    Directory of Open Access Journals (Sweden)

    J. Kalisch

    2012-10-01

    Full Text Available The aim of this study is to determine cloud-type resolved cloud radiative budgets and cloud radiative effects from surface measurements of broadband radiative fluxes over the Atlantic Ocean. Furthermore, based on simultaneous observations of the state of the cloudy atmosphere, a radiative closure study has been performed by means of the ECHAM5 single column model in order to identify the model's ability to realistically reproduce the effects of clouds on the climate system.

    An extensive database of radiative and atmospheric measurements has been established along five meridional cruises of the German research icebreaker Polarstern. Besides pyranometer and pyrgeometer for downward broadband solar and thermal radiative fluxes, a sky imager and a microwave radiometer have been utilized to determine cloud fraction and cloud type on the one hand and temperature and humidity profiles as well as liquid water path for warm non-precipitating clouds on the other hand.

    Averaged over all cruise tracks, we obtain a total net (solar + thermal radiative flux of 144 W m−2 that is dominated by the solar component. In general, the solar contribution is large for cirrus clouds and small for stratus clouds. No significant meridional dependencies were found for the surface radiation budgets and cloud effects. The strongest surface longwave cloud effects were shown in the presence of low level clouds. Clouds with a high optical density induce strong negative solar radiative effects under high solar altitudes. The mean surface net cloud radiative effect is −33 W m−2.

    For the purpose of quickly estimating the mean surface longwave, shortwave and net cloud effects in moderate, subtropical and tropical climate regimes, a new parameterisation was created, considering the total cloud amount and the solar zenith angle.

    The ECHAM5 single column model provides a surface net cloud effect that is more

  19. UK Nuclear Science Forum. Progress report: Data studies during 2000

    International Nuclear Information System (INIS)

    Nichols, A.L.

    2001-06-01

    The UK Nuclear Science Forum (UKNSF) now meets once per year to discuss issues of direct relevance to forum members, and to review nuclear data for application in the UK nuclear industry. Links are also maintained through the year, mainly through e-mail and the normal postal system. Work of immediate interest includes the measurement and evaluation of decay data (e.g., half-lives and gamma-ray emission probabilities), fission yields and thermal neutron cross sections; all known UK studies in 2000 are summarised in this document. Specific applications and international links of relevance in the field of nuclear data are also described

  20. Semantic e-Science in Space Physics - A Case Study

    Science.gov (United States)

    Narock, T.; Yoon, V.; Merka, J.; Szabo, A.

    2009-05-01

    Several search and retrieval systems for space physics data are currently under development in NASA's heliophysics data environment. We present a case study of two such systems, and describe our efforts in implementing an ontology to aid in data discovery. In doing so we highlight the various aspects of knowledge representation and show how they led to our ontology design, creation, and implementation. We discuss advantages that scientific reasoning allows, as well as difficulties encountered in current tools and standards. Finally, we present a space physics research project conducted with and without e-Science and contrast the two approaches.

  1. Radiative effects of clouds and cryosphere in the Antarctic

    Directory of Open Access Journals (Sweden)

    Takashi Yamanouchi

    1997-03-01

    Full Text Available Examination of the effects of clouds, ice sheet and sea ice on the radiation budget in the Antarctic using Earth Radiation Budget Experiment (ERBE data were reported. The continental ice sheet affects not only the albedo, but also the surface temperature because of elevation, and hence the OLR. Sea ice, which is a critical climate feedback factor, appears to have less impact on radiation than do clouds. However, these surfaces lie underneath clouds, and it was found that the independent effect of sea ice is as large as that of clouds, and clouds are masking the radiative effect of sea ice by more than half. The radiation budget at the top of the atmosphere from satellite observation and that at the surface from the surface radiation measurements at Syowa and South Pole Stations were compared. Cloud radiative forcing at both stations for the surface, atmosphere and top of the atmosphere was derived.

  2. Radiation effects on organic materials in nuclear plants. Final report

    International Nuclear Information System (INIS)

    Bruce, M.B.; Davis, M.V.

    1981-11-01

    A literature search was conducted to identify information useful in determining the lowest level at which radiation causes damage to nuclear plant equipment. Information was sought concerning synergistic effects of radiation and other environmental stresses. Organic polymers are often identified as the weak elements in equipment. Data on radiation effects are summarized for 50 generic name plastics and 16 elastomers. Coatings, lubricants, and adhesives are treated as separate groups. Inorganics and metallics are considered briefly. With a few noted exceptions, these are more radiation resistant than organic materials. Some semiconductor devices and electronic assemblies are extremely sensitive to radiation. Any damage threshold including these would be too low to be of practical value. With that exception, equipment exposed to less than 10 4 rads should not be significantly affected. Equipment containing no Teflon should not be significantly affected by 10 5 rads. Data concerning synergistic effects and radiation sensitization are discussed. The authors suggest correlations between the two effects

  3. Numerical simulation of long-term radiation effects for MOSFETs

    International Nuclear Information System (INIS)

    Wei Yuan; Xie Honggang; Gong Ding; Zhu Jinhui; Niu Shengli; Huang Liuxing

    2013-01-01

    A coupled algorithm is introduced to simulate the long-term radiation effects of MOSFETs, which combines particle transport with semiconductor governing equations. The former is dealt with Monte-Carlo method, and the latter is solved by finite-volume method. The trapped charge in SiO 2 and the free charge in Si are both described by the drift-diffusion model, and the deposited energy by incident particles can be coupled with the continuous equations of charge, acting as a source item. The discrete form of governing equations is obtained using the finite-volume method, and the numerical solutions of these equations are the long-term radiation response result of MOSFETs. The threshold voltage shift and off-state leakage current of an irradiated MOSFET are simulated with the coupled algorithm respectively, showing a good accordance with results by other calculations. (authors)

  4. Radiation effects testing at the 88-Inch Cyclotron at LBNL

    International Nuclear Information System (INIS)

    McMahan, Margaret A.; Koga, Rokotura

    2002-01-01

    The effects of ionizing particles on sensitive microelectronics is an important component of the design of systems as diverse as satellites and space probes, detectors for high energy physics experiments and even internet server farms. Understanding the effects of radiation on human cells is an equally important endeavor directed towards future manned missions in space and towards cancer therapy. At the 88-Inch Cyclotron at the Berkeley Laboratory, facilities are available for radiation effects testing (RET) with heavy ions and with protons. The techniques for doing these measurements and the advantages of using a cyclotron will be discussed, and the Cyclotron facilities will be compared with other facilities worldwide. RET of the same part at several facilities of varying beam energy can provide tests of the simple models used in this field and elucidate the relative importance of atomic and nuclear effects. The results and implications of such measurements will be discussed

  5. Double-photoionization of helium including quadrupole radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Colgan, James [Los Alamos National Laboratory; Ludlow, J A [AUBURN UNIV; Lee, Teck - Ghee [AUBURN UNIV; Pindzola, M S [AUBURN UNIV; Robicheaux, F [AUBURN UNIV

    2009-01-01

    Non-perturbative time-dependent close-coupling calculations are carried out for the double photoionization of helium including both dipole and quadrupole radiation effects. At a photon energy of 800 eV, accessible at CUlTent synchrotron light sources, the quadrupole interaction contributes around 6% to the total integral double photoionization cross section. The pure quadrupole single energy differential cross section shows a local maxima at equal energy sharing, as opposed to the minimum found in the pure dipole single energy differential cross section. The sum of the pure dipole and pure quadrupole single energy differentials is insensitive to non-dipole effects at 800 eV. However, the triple differential cross section at equal energy sharing of the two ejected electrons shows strong non-dipole effects due to the quadrupole interaction that may be experimentally observable.

  6. Introduction to workshop on radiation effects in nuclear waste materials

    International Nuclear Information System (INIS)

    Matzke, H.

    1988-01-01

    The workshop consisted of an invited lecture for REI-4, treating radiation damage in nuclear fuels as well as giving an introduction to the field of damage in waste matrices, of invited and contributed lectures to the workshop and to REI as well as of discussions and round table meetings. The contributions available as manuscripts are included on the following pages of these proceedings. At the end, a short summary with recommendations for future work has been added. It is hoped that the stimulating discussions of the workshop will help to continue the work in the field of radiation effects in waste matrices in an effective way. The organizer believes that there are good reasons for this hope and he thanks all scientists who contributed to the success of the workshop, as well as members of the organizing committee of REI-4 for their help. (orig.)

  7. Science and Cooking: Motivating the Study of Freshman Physics

    Science.gov (United States)

    Weitz, David

    2011-03-01

    This talk will describe a course offered to Harvard undergraduates as a general education science course, meant to intrduce freshman-level science for non-science majors. The course was a collaboration between world-class chefs and science professors. The chefs introduced concepts of cooking and the professors used these to motivate scientific concepts. The lectures were designed to provide a coherent introduction to freshman physics, primarily through soft matter science. The lectures were supplemented by a lab experiments, designed by a team of very talented graduate students and post docs, that supplemented the science taught in lecture. The course was very successful in motivating non-science students to learn, and even enjoy, basic science concepts. This course depended on contributions from Michael Brenner, Otger Campas, Amy Rowat and a team of talented graduate student teaching fellows.

  8. A Meta-Synthesis of Turkish Studies in Science Process Skills

    Science.gov (United States)

    Yildirim, Murat; Çalik, Muammer; Özmen, Haluk

    2016-01-01

    This study thematically evaluates Turkish studies in science process skills (SPS) from 2000 to 2015. In looking for SPS studies, the authors entered the keywords "process skills, science process skills, science education and Turkey/Turkish" in well-known databases (i.e., Academic Search Complete, Education Research Complete, ERIC, and…

  9. Hispanic Women Overcoming Deterrents to Computer Science: A Phenomenological Study

    Science.gov (United States)

    Herling, Lourdes

    2011-01-01

    The products of computer science are important to all aspects of society and are tools in the solution of the world's problems. It is, therefore, troubling that the United States faces a shortage in qualified graduates in computer science. The number of women and minorities in computer science is significantly lower than the percentage of the…

  10. Achieving equity through critical science agency: An ethnographic study of African American students in a health science career academy

    Science.gov (United States)

    Haun-Frank, Julie

    The purpose of this study was to examine the potential of a High School Health Science Career Academy to support African American students' science career trajectories. I used three key theoretical tools---critical science agency (Basu, 2007; Calabrese Barton & Tan, 2008), power (Nespor, 1994), and cultural production (Carlone, 2004; Eisenhart & Finkel, 1998) to highlight the intersections between the career trajectory implied by the Academy (its curriculum, classroom activities, and clinical experiences) and the students' pursued career trajectories. Data was collected over five months and included individual student interviews, group interviews, parent and administrator interviews, field notes from a culminating medical course and clinical internship, and Academy recruitment documents. The results of this study suggest that participants pursued a health science career for altruistic purposes and the Academy was a resource they drew upon to do so. However, the meanings of science and science person implied by the Academy hindered the possibility for many participants' to advance their science career trajectories. While the Academy promised to expose students to a variety of high-status health care roles, they were funneled into feminine, entry-level positions. This study adds to previous underrepresentation literature by contextualizing how identity-related factors influence African American students' career attainment.

  11. Science for Survival: The Modern Synthesis of Evolution and The Biological Sciences Curriculum Study

    Science.gov (United States)

    Green, Lisa Anne

    In this historical dissertation, I examined the process of curriculum development in the Biological Sciences Curriculum Study (BSCS) in the United States during the period 1959-1963. The presentation of evolution in the high school texts was based on a more robust form of Darwinian evolution which developed during the 1930s and 1940s called "the modern synthesis of evolution." Building primarily on the work of historians Vassiliki Smocovitis and John L. Rudolph, I used the archival papers and published writings of the four architects of the modern synthesis and the four most influential leaders of the BSCS in regards to evolution to investigate how the modern synthetic theory of evolution shaped the BSCS curriculum. The central question was "Why was evolution so important to the BSCS to make it the central theme of the texts?" Important answers to this question had already been offered in the historiography, but it was still not clear why every citizen in the world needed to understand evolution. I found that the emphasis on natural selection in the modern synthesis shifted the focus away from humans as passive participants to the recognition that humans are active agents in their own cultural and biological evolution. This required re-education of the world citizenry, which was accomplished in part by the BSCS textbooks. I also found that BSCS leaders Grobman, Glass, and Muller had serious concerns regarding the effects of nuclear radiation on the human gene pool, and were actively involved in informing th public. Lastly, I found that concerns of 1950s reform eugenicists were addressed in the BSCS textbooks, without mentioning eugenics by name. I suggest that the leaders of the BSCS, especially Bentley Glass and Hermann J. Muller, thought that students needed to understand genetics and evolution to be able to make some of the tough choices they might be called on to make as the dominant species on earth and the next reproductive generation in the nuclear age. This

  12. Science-Relevant Curiosity Expression and Interest in Science: An Exploratory Study

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    Luce, Megan R.; Hsi, Sherry

    2015-01-01

    In efforts to understand and promote long-term interest in science, much work has focused on measuring students' interest in topics of science, typically with surveys. This approach has challenges, as interest in a topic may not necessarily indicate interest in scientific practices and pursuits. An underexplored and perhaps productive way to…

  13. Assessment of the Forensic Sciences Profession: A Legal Study Concerning the Forensic Sciences Personnel. Volume III.

    Science.gov (United States)

    Schroeder, Oliver, Jr.

    The place and function of forensic sciences personnel in American criminal law and court procedure, and the criteria used by criminal trial judges and lawyers to assess the value of forensic sciences personnel were investigated. Federal, state, Virgin Island, and Puerto Rican laws were examined, and a search of the medical and legal literature…

  14. Planetary Science Technology Infusion Study: Findings and Recommendations Status

    Science.gov (United States)

    Anderson, David J.; Sandifer, Carl E., II; Sarver-Verhey, Timothy R.; Vento, Daniel M.; Zakrajsek, June F.

    2014-01-01

    The Planetary Science Division (PSD) within the National Aeronautics and Space Administrations (NASA) Science Mission Directorate (SMD) at NASA Headquarters sought to understand how to better realize a scientific return on spacecraft system technology investments currently being funded. In order to achieve this objective, a team at NASA Glenn Research Center was tasked with surveying the science and mission communities to collect their insight on technology infusion and additionally sought inputs from industry, universities, and other organizations involved with proposing for future PSD missions. This survey was undertaken by issuing a Request for Information (RFI) activity that requested input from the proposing community on present technology infusion efforts. The Technology Infusion Study was initiated in March 2013 with the release of the RFI request. The evaluation team compiled and assessed this input in order to provide PSD with recommendations on how to effectively infuse new spacecraft systems technologies that it develops into future competed missions enabling increased scientific discoveries, lower mission cost, or both. This team is comprised of personnel from the Radioisotope Power Systems (RPS) Program and the In-Space Propulsion Technology (ISPT) Program staff.The RFI survey covered two aspects of technology infusion: 1) General Insight, including: their assessment of barriers to technology infusion as related to infusion approach; technology readiness; information and documentation products; communication; integration considerations; interaction with technology development areas; cost-capped mission areas; risk considerations; system level impacts and implementation; and mission pull. 2) Specific technologies from the most recent PSD Announcements of Opportunities (AOs): The Advanced Stirling Radioisotope Generator (ASRG), aerocapture and aeroshell hardware technologies, the NASA Evolutionary Xenon Thruster (NEXT) ion propulsion system, and the

  15. Influence of cloud radiative effects on tropical circulation and hydrological cycle in the Mid-Holocene

    Science.gov (United States)

    Izumi, Kenji; Kageyama, Masa; Bony, Sandrine; Braconnot, Pascale

    2016-04-01

    Paleoenvironmental data in particular, vegetation and lake-status at mid-Holocene (6,000 years ago) in Sahara shows that African monsoon extended much further north than today. Much of this change results from the changes in insolation driven by precession of the Earth's orbit, but in the state-of-the-art climate models, this factor alone is insufficient to explain the magnitude of the change. Previous studies showed that ocean and vegetation feedbacks affect the mid-Holocene monsoon and that the incorporation of these feedbacks in models improves the simulation of the hydrological cycle. However, it is not sufficient to reduce the discrepancies between simulated and reconstructed surface climates. In this study, we investigate the extent to which the simulation of cloud-radiative effects matters for the simulation of paleo-climatic changes, and past changes in the position and strength of the tropical rain belts in particular. This is done by running a general circulation model with and without clouds-radiation interactions using the IPSL model. The impact of cloud -radiative effects, which prevents the precipitation band to move north, on the tropical circulation and precipitation changes in mid-Holocene experiments will be discussed. Additionally, we will show the simulated effects of land cover change over Sahara.

  16. Analysis of Radiation Effects in Digital Subtraction Angiography of Intracranial Artery Stenosis.

    Science.gov (United States)

    Guo, Chaoqun; Shi, Xiaolei; Ding, Xianhui; Zhou, Zhiming

    2018-04-21

    Intracranial artery stenosis (IAS) is the most common cause for acute cerebral accidents. Digital subtraction angiography (DSA) is the gold standard to detect IAS and usually brings excess radiation exposure to examinees and examiners. The artery pathology might influence the interventional procedure, causing prolonged radiation effects. However, no studies on the association between IAS pathology and operational parameters are available. A retrospective analysis was conducted on 93 patients with first-ever stroke/transient ischemic attack, who received DSA examination within 3 months from onset in this single center. Comparison of baseline characteristics was determined by 2-tailed Student's t-test or the chi-square test between subjects with and without IAS. A binary logistic regression analysis was performed to determine the association between IAS pathology and the items with a P value 42 with IAS and 51 without IAS) in this study. The 2 groups shared no significance of the baseline characteristics (P > 0.05). We found a significantly higher total time, higher kerma area product, greater total dose, and greater DSA dose in the IAS group than in those without IAS (P IAS pathology (P 0.05). IAS pathology would indicate a prolonged total time of DSA procedure in clinical practice. However, the radiation effects would not change with pathologic changes. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Munazza's story: Understanding science teaching and conceptions of the nature of science in Pakistan through a life history study

    Science.gov (United States)

    Halai, Nelofer

    In this study I have described and tried to comprehend how a female science teacher understands her practice. Additionally, I have developed some understanding of her understanding of the nature of science. While teaching science, a teacher projects messages about the nature of science that can be captured by observations and interviews. Furthermore, the manner is which a teacher conceptualizes science for teaching, at least in part, depends on personal life experiences. Hence, I have used the life history method to understand Munazza's practice. Munazza is a young female science teacher working in a private, co-educational school for children from middle income families in Karachi, Pakistan. Her stories are central to the study, and I have represented them using a number of narrative devices. I have woven in my own stories too, to illustrate my perspective as a researcher. The data includes 13 life history interviews and many informal conversations with Munazza, observations of science teaching in classes seven and eight, and interviews with other science teachers and administrative staff of the school. Munazza's personal biography and experiences of school and undergraduate courses has influenced the way she teaches. It has also influenced the way she does not teach. She was not inspired by her science teachers, so she has tried not to teach the way she was taught science. Contextual factors, her conception of preparation for teaching as preparation for subject content and the tension that she faces in balancing care and control in her classroom are some factors that influence her teaching. Munazza believes that science is a stable, superior and value-free way of knowing. In trying to understand the natural world, observations come first, which give reliable information about the world leading inductively to a "theory". Hence, she relies a great deal on demonstrations in the class where students "see" for themselves and abstract the scientific concept from the

  18. How science teachers balance religion and evolution in the science classroom: A case study of science classes in a Florida Public School District

    Science.gov (United States)

    Willems, Pierre Dominique

    The purpose of this case study was to research how science teachers balance both religion and evolution in the science classroom with as little controversy as possible. In this study I attempted to provide some insight on how teachers are currently teaching evolution in their science classes in light of the religious beliefs of the students as well as their own. The case study was conducted in a school district in Florida where I attempted to answer the following questions: (a) How do science teachers in the Florida School District (FSD) approach the religion--evolution issue in preparing students for a career in a field of science? (b) How do science teachers in the FSD reconcile the subject of evolution with the religious views of their students? (c) How do science teachers in the FSD reconcile their own religious views with the teaching of evolution? (d) How do science teachers in the FSD perceive the relationship between religion and science? The data was collected through interviews with two high school teachers, and one middle school teacher, by observing each participant teach, by collecting site documents and by administering an exploratory survey to student volunteers. Analysis was conducted by open coding which produced four themes from which the research questions were answered and the survey answers were counted to produce the percentages displayed in the tables in chapter four. The teachers avoided discussion on religiously oriented questions or statements by the students and did not reveal their own religious orientation. The topic of microevolution appeared to reduce stress in the classroom environment, as opposed to addressing macroevolution.

  19. An interactional ethnographic study of the construction of literate practices of science and writing in a university science classroom

    Science.gov (United States)

    Sena, Nuno Afonso De Freitas Lopes De

    An interactional ethnographic study informed by a sociocultural perspective was conducted to examine how a professor and students discursively and interactionally shaped the basis for engaging in the work of a community of geologists. Specifically, the study examined the role the Question of the Day, an interactive writing activity in the lecture, in affording students opportunities for learning the literate practices of science and how to incorporate them in thinking critically. A writing-intensive, introductory oceanography course given in the Geological Sciences Department was chosen because the professor designed it to emphasize writing in the discipline and science literacy within a science inquiry framework. The study was conducted in two phases: a pilot in 2002 and the current study in the Spring Quarter of 2003. Grounded in the view that members in a classroom construct a culture, this study explored the daily construction of the literate practices of science and writing. This view of classrooms was informed by four bodies of research: interactional ethnography, sociolinguistics sociology of science and Writing In the Disciplines. Through participant observation, data were collected in the lecture and laboratory settings in the form of field notes, video, interviews, and artifacts to explore issues of science literacy in discourse, social action, and writing. Examination of participation in the Question of the Day interactive writing activity revealed that it played a key role in initiating and supporting a view of science and inquiry. As the activity permitted collaboration, it encouraged students to engage in the social process to critically explore a discourse of science and key practices with and through their writing. In daily interaction, participants were shown to take up social positions as scientist and engage in science inquiry to explore theory, examine data, and articulately reformulate knowledge in making oral and written scientific arguments

  20. The Black Cultural Ethos and science teachers' practices: A case study exploring how four high school science teachers meet their African American students' needs in science

    Science.gov (United States)

    Strachan, Samantha L.

    The underachievement of African American students in science has been a persistent problem in science education. The achievement patterns of African American students indicate that researchers must take a closer look at the types of practices that are being used to meet these students' needs in science classrooms. Determining why science teachers decide to employ certain practices in their classrooms begins with a careful examination of teachers' beliefs as well as their instructional approaches. The purpose of this study was to explore four urban high school science teachers' beliefs about their African American students' learning needs and to investigate how these teachers go about addressing students' needs in science classrooms. This research study also explored the extent to which teachers' practices aligned with the nine dimensions of an established cultural instructional theory, namely the Black Cultural Ethos. Qualitative research methods were employed to gather data from the four teachers. Artifact data were collected from the teachers and they were interviewed and observed. Believing that their students had academic-related needs as well as needs tied to their learning preferences, the four science teachers employed a variety of instructional strategies to meet their students where they were in learning. Overall, the instructional strategies that the teachers employed to meet their students' needs aligned with five of the nine tenets of the Black Cultural Ethos theory.