Science.gov

Sample records for adequate experimental conditions

  1. Anatomical features for the adequate choice of experimental animal models in biomedicine: I. Fishes.

    PubMed

    D'Angelo, Livia; Lossi, Laura; Merighi, Adalberto; de Girolamo, Paolo

    2016-05-01

    Fish constitute the oldest and most diverse class of vertebrates, and are widely used in basic research due to a number of advantages (e.g., rapid development ex-utero, large-scale genetic screening of human disease). They represent excellent experimental models for addressing studies on development, morphology, physiology and behavior function in other related species, as well as informative analysis of conservation and diversity. Although less complex, fish share many anatomical and physiological features with mammals, including humans, which make them an important complement to research in mammalian models. In this review we describe and compare the most relevant anatomical features of the most used teleostean species in research, to be taken into consideration when selecting an animal model: zebrafish (Danio rerio), medaka (Oryzias latypes), the turquoise killifish (Nothobranchius furzeri), and goldfish (Carassius auratus). Zebrafish and medaka are the mainstream models for genetic manipulability and studies on developmental biology; the turquoise killifish is an excellent model for aging research; goldfish has been largely employed for neuroendocrine studies.

  2. Experimental database of E110 claddings exposed to accident conditions

    NASA Astrophysics Data System (ADS)

    Perez-Feró, Erzsébet; Győri, Csaba; Matus, Lajos; Vasáros, László; Hózer, Zoltán; Windberg, Péter; Maróti, László; Horváth, Márta; Nagy, Imre; Pintér-Csordás, Anna; Novotny, Tamás

    2010-02-01

    An experimental database of E110 alloy has been developed on the basis of about 600 separate and combined effect tests of the Hungarian Academy of Sciences KFKI Atomic Energy Research Institute. It contains the data of oxidation, ballooning, tensile and compression tests, the results of post-test investigations, photos, figures, information concerning the test conditions and the corresponding English-language publications. The aim of this database is to give adequate information on the E110 cladding behaviour (oxidation, hydrogen uptake, mechanical performance) under accident conditions and to provide valuable experimental data for model development and code validation. This database is a part of the International Fuel Performance Experimental Database. It is accessible on-line, via the internet. This paper gives an overview of the experiments, the test facilities and conditions involved in the database. It presents the most important results and consequences and introduces the directory structure of the database.

  3. Influence of high and low protein intakes on age-related bone loss in rats submitted to adequate or restricted energy conditions.

    PubMed

    Mardon, Julie; Habauzit, Véronique; Trzeciakiewicz, Anna; Davicco, Marie-Jeanne; Lebecque, Patrice; Mercier, Sylvie; Tressol, Jean-Claude; Horcajada, Marie-Noëlle; Demigné, Christian; Coxam, Véronique

    2008-05-01

    Low energy and protein intake has been suggested to contribute to the increased incidence of osteoporosis in the elderly. The impact of dietary protein on bone health is still a matter of debate. Therefore, we examined the effect of the modulation of protein intake under adequate or deficient energy conditions on bone status in 16-month-old male rats. The animals were randomly allocated to six groups (n = 10/group). Control animals were fed a diet providing either a normal-protein content (13%, C-NP) or a high-protein content (26%) (C-HP). The other groups received a 40% protein/energy-restricted diet (PER-NP and PER-HP) or a normal protein/energy-restricted diet (ER-NP and ER-HP). After 5 months of the experiment, protein intake (13% or 26%) did not modulate calcium retention or bone status in those rats, although a low-grade metabolic acidosis was induced with the HP diet. Both restrictions (PER and ER) decreased femoral bone mineral density and fracture load. Plasma osteocalcin and urinary deoxypyridinoline levels were lowered, suggesting a decrease in bone turnover in the PER and ER groups. Circulating insulin-like growth factor-I levels were also lowered by dietary restrictions, together with calcium retention. Adequate protein intake in the ER condition did not elicit any bone-sparing effect compared to PER rats. In conclusion, both energy and protein deficiencies may contribute to age-related bone loss. This study highlights the importance of sustaining adequate energy and protein provision to preserve skeletal integrity in the elderly.

  4. Development for Thermophoresis Experimental Under Microgravity Condition

    NASA Astrophysics Data System (ADS)

    Suardi, Mirnah Binti; Razali, Mohd Azahari bin; Khalid, Amir bin; Salleh, Hamidon bin; Sapit, Azwan; Mohammed, Akmal Nizam bin; Hushim, Mohd Faisal bin

    2016-11-01

    In the temperature field, a small particle will move towards the lower temperature side. This phenomenon is called thermophoresis, which influences the movement of soot particles in exhaust gas from combustors. It is important to understand the behavior of soot particles in the combustion field for emission control. The main problem for measuring the thermophoretic velocity is the natural convection. The velocity of such natural convection is usually comparable to the thermophoretic velocity and cannot be measured directly. To avoid this problem, experiments should be conducted under microgravity conditions. . In the present work, device has been developed for conducting experiments repeatedly under a microgravity environment in a very short period time, i.e. 0.3 s, by means of the free-fall method, to accumulate data of the thermophoretic velocity. Experiments have been conducted to measure the movement of particles in the microgravity environment with and without temperature gradient. For the former experiment, it is seen that the particles has almost no movement in the horizontal and the vertical directions. Results confirmed that there is negligible effect of blowing and gravitational on the particles movement. For the later one, experiments have been done in a surrounding of a pure gas of argon. The thermophoretic velocity is measured at 313±2 K for various pressure conditions from 20 kPa to 100 kPa. The thermophoretic velocity for each particle is individually measured, and the mean value and its 95% confidence interval for each experimental condition are statistically obtained. Result from experiments are compared with the theory and satisfactorily agreement is found for tested gas.

  5. Experimental airfoil characterization under tailored turbulent conditions

    NASA Astrophysics Data System (ADS)

    Heißelmann, Hendrik; Peinke, Joachim; Hölling, Michael

    2016-09-01

    Studies of the impact of turbulent inflow conditions on the airfoil characteristics were performed within the EU FP7 project AVATAR. The aim of this study is to provide data for the validation of simulations and the improvement of engineering tools. Chord-wise pressure distributions and highly-resolved force data of the wind turbine dedicated DU 00-W-212 profile were measured in the wind tunnel in two tailored turbulent inflow conditions generated with an active grid. A sinusoidal and an intermittent pattern with customized inflow angle fluctuations were generated providing two significantly different distributions of reduced frequencies. The obtained pressure distributions and polars from the unsteady patterns are compared to the laminar baseline case.

  6. Undernutrition among children under 5 years of age in Yemen: Role of adequate childcare provided by adults under conditions of food insecurity

    PubMed Central

    Al-Sobaihi, Saber; Nakamura, Keiko; Kizuki, Masashi

    2016-01-01

    Objective: This study examined the associations between the adequacy of childcare provided by adult caretakers and childhood undernutrition in rural Yemen, independent of household wealth and food consumption. Methods: We analyzed data of 3,549 children under the age of 5 years living in rural areas of Yemen based on the 2013 Yemen Baseline Survey of Mother and Child Health. Nutritional status was evaluated by the presence of underweight, stunting, and wasting according to the World Health Organization child growth standards. The impact of childcare including leaving children alone, putting older children into labor force, and the use of antenatal care while pregnant on child undernutrition was assessed and adjusted for food consumption by children, household composition, demographic and educational background of caretakers, and household wealth. Results: The prevalence of underweight, stunting, and wasting was 46.2%, 62.6%, and 11.1%, respectively. Not leaving children alone, keeping children out of the labor force, and use of antenatal care were associated with a lower risk of underweight (odds ratio [OR] = 0.84, P = 0.016; OR = 0.84, P = 0.036; and OR = 0.85, P = 0.042) and stunting (OR = 0.80, P = 0.004; OR = 0.82, P = 0.024; and OR = 0.78, P = 0.003). After further adjustment for food consumption, the associations between adequate childcare indicators and lower odds of stunting remained significant (OR = 0.73, P = 0.025; OR = 0.72, P = 0.046; and OR = 0.76, P = 0.038). Conclusions: A marked prevalence of stunting among rural children in Yemen was observed. Adequate childcare by adult caretakers in families is associated with a lower incidence of underweight and stunting among children under 5 years of age. Promoting adequate childcare by adult household members is a feasible option for reducing undernutrition among children in rural Yemen. PMID:27928456

  7. Undernutrition among children under 5 years of age in Yemen: Role of adequate childcare provided by adults under conditions of food insecurity.

    PubMed

    Al-Sobaihi, Saber; Nakamura, Keiko; Kizuki, Masashi

    2016-01-01

    Objective: This study examined the associations between the adequacy of childcare provided by adult caretakers and childhood undernutrition in rural Yemen, independent of household wealth and food consumption. Methods: We analyzed data of 3,549 children under the age of 5 years living in rural areas of Yemen based on the 2013 Yemen Baseline Survey of Mother and Child Health. Nutritional status was evaluated by the presence of underweight, stunting, and wasting according to the World Health Organization child growth standards. The impact of childcare including leaving children alone, putting older children into labor force, and the use of antenatal care while pregnant on child undernutrition was assessed and adjusted for food consumption by children, household composition, demographic and educational background of caretakers, and household wealth. Results: The prevalence of underweight, stunting, and wasting was 46.2%, 62.6%, and 11.1%, respectively. Not leaving children alone, keeping children out of the labor force, and use of antenatal care were associated with a lower risk of underweight (odds ratio [OR] = 0.84, P = 0.016; OR = 0.84, P = 0.036; and OR = 0.85, P = 0.042) and stunting (OR = 0.80, P = 0.004; OR = 0.82, P = 0.024; and OR = 0.78, P = 0.003). After further adjustment for food consumption, the associations between adequate childcare indicators and lower odds of stunting remained significant (OR = 0.73, P = 0.025; OR = 0.72, P = 0.046; and OR = 0.76, P = 0.038). Conclusions: A marked prevalence of stunting among rural children in Yemen was observed. Adequate childcare by adult caretakers in families is associated with a lower incidence of underweight and stunting among children under 5 years of age. Promoting adequate childcare by adult household members is a feasible option for reducing undernutrition among children in rural Yemen.

  8. The mycotoxin distribution in maize milling fractions under experimental conditions.

    PubMed

    Burger, H-M; Shephard, G S; Louw, W; Rheeder, J P; Gelderblom, W C A

    2013-07-01

    Mycotoxin contamination of maize and maize-based food and feed products poses a health risk to humans and animals if not adequately controlled and managed. The current study investigates the effect of dry milling on the reduction of fumonisins (FB), deoxynivalenol (DON) and zearalenone (ZEA) in maize. Five composite samples, constructed to represent different mycotoxin contamination levels were degermed yielding degermed maize and the germ. The degermed maize was milled under laboratory conditions and four major milling fractions (SPECIAL, SUPER, semolina (SEM) and milling hominy feed) collected. The whole maize, degermed maize and total hominy feed (germ+milling hominy feed) were reconstructed to ensure homogenous samples for mycotoxin analyses. For comparison, commercial dry milling fractions (whole maize, SPECIAL, SUPER and total hominy feed), collected from three South African industrial mills, were analysed for the same mycotoxins and hence a more accurate assessment of the distribution between the different milling fractions. The distribution of the mycotoxins during the experimental dry milling of the degermed maize differs, with FB mainly concentrated in the SPECIAL, DON in the SEM whereas ZEA was equally distributed between the two milling fractions. Distribution of mycotoxins between the fractions obtained during commercial dry milling generally provided similar results with the total hominy feed containing the highest and the SUPER milling fractions the lowest mycotoxin levels although variations existed. Although milling is an effective way to reduce mycotoxins in maize, kernel characteristics and resultant fungal colonisation may impact on the distribution of specific mycotoxins among the different milling fractions. Differences in industrial dry milling practices and problems encountered in sampling bulk maize remain a large problem in assessing mycotoxin contamination in milling fractions intended for human consumption.

  9. Counterbalancing for Serial Order Carryover Effects in Experimental Condition Orders

    ERIC Educational Resources Information Center

    Brooks, Joseph L.

    2012-01-01

    Reactions of neural, psychological, and social systems are rarely, if ever, independent of previous inputs and states. The potential for serial order carryover effects from one condition to the next in a sequence of experimental trials makes counterbalancing of condition order an essential part of experimental design. Here, a method is proposed…

  10. Vaccination of Elk (Cervus canadensis) with Brucella abortus Strain RB51 Overexpressing Superoxide Dismutase and Glycosyltransferase Genes Does Not Induce Adequate Protection against Experimental Brucella abortus Challenge

    PubMed Central

    Nol, Pauline; Olsen, Steven C.; Rhyan, Jack C.; Sriranganathan, Nammalwar; McCollum, Matthew P.; Hennager, Steven G.; Pavuk, Alana A.; Sprino, Phillip J.; Boyle, Stephen M.; Berrier, Randall J.; Salman, Mo D.

    2016-01-01

    In recent years, elk (Cervus canadensis) have been implicated as the source of Brucella abortus infection for numerous cattle herds in the Greater Yellowstone Area. In the face of environmental and ecological changes on the landscape, the range of infected elk is expanding. Consequently, the development of effective disease management strategies for wild elk herds is of utmost importance, not only for the prevention of reintroduction of brucellosis to cattle, but also for the overall health of the Greater Yellowstone Area elk populations. In two studies, we evaluated the efficacy of B. abortus strain RB51 over-expressing superoxide dismutase and glycosyltransferase for protecting elk from infection and disease caused by B. abortus after experimental infection with a virulent B. abortus strain. Our data indicate that the recombinant vaccine does not protect elk against brucellosis. Further, work is needed for development of an effective brucellosis vaccine for use in elk. PMID:26904509

  11. Vaccination of Elk (Cervus canadensis) with Brucella abortus Strain RB51 Overexpressing Superoxide Dismutase and Glycosyltransferase Genes Does Not Induce Adequate Protection against Experimental Brucella abortus Challenge.

    PubMed

    Nol, Pauline; Olsen, Steven C; Rhyan, Jack C; Sriranganathan, Nammalwar; McCollum, Matthew P; Hennager, Steven G; Pavuk, Alana A; Sprino, Phillip J; Boyle, Stephen M; Berrier, Randall J; Salman, Mo D

    2016-01-01

    In recent years, elk (Cervus canadensis) have been implicated as the source of Brucella abortus infection for numerous cattle herds in the Greater Yellowstone Area. In the face of environmental and ecological changes on the landscape, the range of infected elk is expanding. Consequently, the development of effective disease management strategies for wild elk herds is of utmost importance, not only for the prevention of reintroduction of brucellosis to cattle, but also for the overall health of the Greater Yellowstone Area elk populations. In two studies, we evaluated the efficacy of B. abortus strain RB51 over-expressing superoxide dismutase and glycosyltransferase for protecting elk from infection and disease caused by B. abortus after experimental infection with a virulent B. abortus strain. Our data indicate that the recombinant vaccine does not protect elk against brucellosis. Further, work is needed for development of an effective brucellosis vaccine for use in elk.

  12. Micromorphology of neurohypophysis of rats under experimental conditions

    NASA Technical Reports Server (NTRS)

    Meitner, E. R.; Proksova, E.

    1979-01-01

    The changes of the quantity of neurosecretory substance in neurohypophysis of rats under various experimental conditions are investigated. Comparing to the norm the quantity of neurosecretion after a long stay in the dark was larger. In animals subjected to immobilization stress the picture of neurohypophysis remained unchanged. It changed only in correlation with the administered water. Results indicate that the immobilization stress, in contradistinction to dolorose stress, has no substantial influence upon the quantity of neurosecretion in neurohypophysis.

  13. [Experimental Conditions and Reliability Analysis of Results of COD components].

    PubMed

    Li, Zhi-hua; Zhang, Yin; Han, Xing; Yu, Ke; Li, Ru-jia

    2015-10-01

    The present study attempts to use SF( OUR(max)/OUR(en)) instead of S(0)/X(0) as an index of optimal initial conditions for determination of COD components by means of respirometry, thereby simplifying the measuring process and the operation can be automated. Further, the ratio of COD consumed by the growth of biomass can be used for the reliability assessment of results. Experimental results show that, experimental conditions for obtaining good results as follows: (1) for samples that composed of a large amount of easily biodegradable components (e. g., synthetic wastewater made by sodium acetate), SF should be in the range of 2.8 to 5.3, and the ratio of COD consumed by growth of biomass should be less than 30%; (2) for samples that composed of both readily biodegradable and slowly biodegradable components (i. e., typical domestic wastewater), SF should be in the range of 5.8 to 6.4, and the ratio of COD consumed by growth of biomass should be less than 30%; (3) and for samples that composed of a large amount of slowly biodegradable industrial wastewater (i. e., landfill leachate), SF should be 15 or less, and the ratio of COD consumed by growth of biomass should be approximately 40%. Therefore, when respirometry is used for the determination of COD components, the optimal conditions in terms of SF increase with the complexity of carbon source.

  14. Experimental study of elliptical jet from sub to supercritical conditions

    SciTech Connect

    Muthukumaran, C. K.; Vaidyanathan, Aravind

    2014-04-15

    The jet mixing at supercritical conditions involves fluid dynamics as well as thermodynamic phenomena. All the jet mixing studies at critical conditions to the present date have focused only on axisymmetric jets. When the liquid jet is injected into supercritical environment, the thermodynamic transition could be well understood by considering one of the important fluid properties such as surface tension since it decides the existence of distinct boundary between the liquid and gaseous phase. It is well known that an elliptical liquid jet undergoes axis-switching phenomena under atmospheric conditions due to the presence of surface tension. The experimental investigations were carried out with low speed elliptical jet under supercritical condition. Investigation of the binary component system with fluoroketone jet and N{sub 2} gas as environment shows that the surface tension force dominates for a large downstream distance, indicating delayed thermodynamic transition. The increase in pressure to critical state at supercritical temperature is found to expedite the thermodynamic transition. The ligament like structures has been observed rather than droplets for supercritical pressures. However, for the single component system with fluoroketone jet and fluoroketone environment shows that the jet disintegrates into droplets as it is subjected to the chamber conditions even for the subcritical pressures and no axis switching phenomenon is observed. For a single component system, as the pressure is increased to critical state, the liquid jet exhibits gas-gas like mixing behavior and that too without exhibiting axis-switching behavior.

  15. New housing conditions: improving the welfare of experimental animals.

    PubMed

    Ottesen, Jan L; Weber, Anett; Gürtler, Hanne; Mikkelsen, Lars Friis

    2004-06-01

    As animal experiments and testing are still a necessary part of the discovery and development of new drugs and do not seem likely to be totally replaced in the foreseeable future, it is important that the care and use of these animals are continuously refined. Since the housing facilities are where most experimental animals spend the major part of their lives, this area should be given special attention to ensure optimal welfare for the animals. In a unique collaboration between a pharmaceutical company and an animal welfare organisation, the housing conditions of mice, rats, guinea-pigs, rabbits and dogs, respectively, were reviewed with focus on the basic needs of the animals. Prototypes for new housing systems satisfying the most important of these basic needs of the animals were developed, with valuable input from international experts with special knowledge of the behaviour of experimental animals. These new housing systems and species-specific, newly introduced socialisation programmes contribute to improved animal welfare and a better occupational health of the animal caretakers. Since these new housing systems are more pleasant and appealing, they may also have the added benefit that they contribute to a broader public acceptance of the use of experimental animals.

  16. Reinforcement learning accounts for moody conditional cooperation behavior: experimental results

    PubMed Central

    Horita, Yutaka; Takezawa, Masanori; Inukai, Keigo; Kita, Toshimasa; Masuda, Naoki

    2017-01-01

    In social dilemma games, human participants often show conditional cooperation (CC) behavior or its variant called moody conditional cooperation (MCC), with which they basically tend to cooperate when many other peers have previously cooperated. Recent computational studies showed that CC and MCC behavioral patterns could be explained by reinforcement learning. In the present study, we use a repeated multiplayer prisoner’s dilemma game and the repeated public goods game played by human participants to examine whether MCC is observed across different types of game and the possibility that reinforcement learning explains observed behavior. We observed MCC behavior in both games, but the MCC that we observed was different from that observed in the past experiments. In the present study, whether or not a focal participant cooperated previously affected the overall level of cooperation, instead of changing the tendency of cooperation in response to cooperation of other participants in the previous time step. We found that, across different conditions, reinforcement learning models were approximately as accurate as a MCC model in describing the experimental results. Consistent with the previous computational studies, the present results suggest that reinforcement learning may be a major proximate mechanism governing MCC behavior. PMID:28071646

  17. Reinforcement learning accounts for moody conditional cooperation behavior: experimental results.

    PubMed

    Horita, Yutaka; Takezawa, Masanori; Inukai, Keigo; Kita, Toshimasa; Masuda, Naoki

    2017-01-10

    In social dilemma games, human participants often show conditional cooperation (CC) behavior or its variant called moody conditional cooperation (MCC), with which they basically tend to cooperate when many other peers have previously cooperated. Recent computational studies showed that CC and MCC behavioral patterns could be explained by reinforcement learning. In the present study, we use a repeated multiplayer prisoner's dilemma game and the repeated public goods game played by human participants to examine whether MCC is observed across different types of game and the possibility that reinforcement learning explains observed behavior. We observed MCC behavior in both games, but the MCC that we observed was different from that observed in the past experiments. In the present study, whether or not a focal participant cooperated previously affected the overall level of cooperation, instead of changing the tendency of cooperation in response to cooperation of other participants in the previous time step. We found that, across different conditions, reinforcement learning models were approximately as accurate as a MCC model in describing the experimental results. Consistent with the previous computational studies, the present results suggest that reinforcement learning may be a major proximate mechanism governing MCC behavior.

  18. Experimental FSO network availability estimation using interactive fog condition monitoring

    NASA Astrophysics Data System (ADS)

    Turán, Ján.; Ovseník, Łuboš

    2016-12-01

    Free Space Optics (FSO) is a license free Line of Sight (LOS) telecommunication technology which offers full duplex connectivity. FSO uses infrared beams of light to provide optical broadband connection and it can be installed literally in a few hours. Data rates go through from several hundreds of Mb/s to several Gb/s and range is from several 100 m up to several km. FSO link advantages: Easy connection establishment, License free communication, No excavation are needed, Highly secure and safe, Allows through window connectivity and single customer service and Compliments fiber by accelerating the first and last mile. FSO link disadvantages: Transmission media is air, Weather and climate dependence, Attenuation due to rain, snow and fog, Scattering of laser beam, Absorption of laser beam, Building motion and Air pollution. In this paper FSO availability evaluation is based on long term measured data from Fog sensor developed and installed at TUKE experimental FSO network in TUKE campus, Košice, Slovakia. Our FSO experimental network has three links with different physical distances between each FSO heads. Weather conditions have a tremendous impact on FSO operation in terms of FSO availability. FSO link availability is the percentage of time over a year that the FSO link will be operational. It is necessary to evaluate the climate and weather at the actual geographical location where FSO link is going to be mounted. It is important to determine the impact of a light scattering, absorption, turbulence and receiving optical power at the particular FSO link. Visibility has one of the most critical influences on the quality of an FSO optical transmission channel. FSO link availability is usually estimated using visibility information collected from nearby airport weather stations. Raw data from fog sensor (Fog Density, Relative Humidity, Temperature measured at each ms) are collected and processed by FSO Simulator software package developed at our Department. Based

  19. Experimental Investigation of Process Conditions in Injection Stretch Blow Moulding

    NASA Astrophysics Data System (ADS)

    Salomeia, Y.; Menary, G.; Armstrong, C. G.

    2007-04-01

    Various processing parameters influence the final product properties in the stretch blow moulding process. These properties are highly dependent on the balance between the stretching of the polymer and blowing times as well as the level of the pressure inside the bottle. A data acquisition system capable of accurately measuring the process conditions within an industrial environment is discussed. Experimental work has been conducted on an industrial stretch blow moulding machine by means of replacing the original stretch rod with one that contains a force cell and a pressure transducer. Correlation between the stretching force, displacement of the rod and the pressure inside the bottle give a better understanding of the process and should allow a more precise final element simulation of the process to be developed.

  20. Experimental Verification of Steel Pipe Collapse under Vacuum Pressure Conditions

    NASA Astrophysics Data System (ADS)

    Autrique, R.; Rodal, E.

    2016-11-01

    Steel pipes are used widely in hydroelectric systems and in pumping systems. Both systems are subject to hydraulic transient effects caused by changes in boundary conditions, such as sudden valve closures, pump failures, or accidents. Water column separation, and its associated vaporization pressure inside the pipe, can cause the collapse of thin walled steel pipes subject to atmospheric pressure, as happened during the well known Oigawa Power Plant accident in Japan, in 1950. The conditions under which thin walled pipes subject to external pressure can collapse have been studied mathematically since the second half of the XIX century, with classical authors Southwell and Von Mises obtaining definitive equations for long and short pipes in the second decade of the XX century, in which the fundamental variables are the diameter to thickness ratio D/t and the length to diameter ratio L/D. In this paper, the predicted critical D/t ratio for steel pipe collapse is verified experimentally, in a physical model able to reproduce hydraulic transients, generating vacuum pressures through rapid upstream valve closures.

  1. Experimental study on the regenerator under actual operating conditions

    NASA Astrophysics Data System (ADS)

    Nam, Kwanwoo; Jeong, Sangkwon

    2002-05-01

    An experimental apparatus was prepared to investigate thermal and hydrodynamic characteristics of the regenerator under its actual operating conditions. The apparatus included a compressor to pressurize and depressurize regenerator with various operating frequencies. Cold end of the regenerator was maintained around 100 K by means of liquid nitrogen container and heat exchanger. Instantaneous gas temperature and mass flow rate were measured at both ends of the regenerator during the whole pressure cycle. Pulsating pressure and pressure drop across the regenerator were also measured. The operating frequency of the pressure cycle was varied between 3 and 60 Hz, which are typical operating frequencies of Gifford-McMahon, pulse tube, and Stirling cryocoolers. First, friction factor for the wire screen mesh was directly determined from room temperature experiments. When the operating frequency was less than 9 Hz, the oscillating flow friction factor was nearly same as the steady flow friction factor for Reynolds number up to 100. For 60 Hz operations, the ratio of oscillating flow friction factor to steady flow one was increased as hydraulic Reynolds number became high. When the Reynolds number was 100, this ratio was about 1.6. Second, ineffectiveness of the regenerator was obtained when the cold-end was maintained around 100 K and the warm-end at 300 K to simulate the actual operating condition of the regenerator in cryocooler. Effect of the operating frequency on ineffectiveness of regenerator was discussed at low frequency range.

  2. Experimental study of choking flow of water at supercritical conditions

    NASA Astrophysics Data System (ADS)

    Muftuoglu, Altan

    Future nuclear reactors will operate at a coolant pressure close to 25 MPa and at outlet temperatures ranging from 500°C to 625°C. As a result, the outlet flow enthalpy in future Supercritical Water-Cooled Reactors (SCWR) will be much higher than those of actual ones which can increase overall nuclear plant efficiencies up to 48%. However, under such flow conditions, the thermal-hydraulic behavior of supercritical water is not fully known, e.g., pressure drop, forced convection and heat transfer deterioration, critical and blowdown flow rate, etc. Up to now, only a very limited number of studies have been performed under supercritical conditions. Moreover, these studies are conducted at conditions that are not representative of future SCWRs. In addition, existing choked flow data have been collected from experiments at atmospheric discharge pressure conditions and in most cases by using working fluids different than water which constrain researchers to analyze the data correctly. In particular, the knowledge of critical (choked) discharge of supercritical fluids is mandatory to perform nuclear reactor safety analyses and to design key mechanical components (e.g., control and safety relief valves, etc.). Hence, an experimental supercritical water facility has been built at Ecole Polytechnique de Montreal which allows researchers to perform choking flow experiments under supercritical conditions. The facility can also be used to carry out heat transfer and pressure drop experiments under supercritical conditions. In this thesis, we present the results obtained at this facility using a test section that contains a 1 mm inside diameter, 3.17 mm long orifice plate with sharp edges. Thus, 545 choking flow of water data points are obtained under supercritical conditions for flow pressures ranging from 22.1 MPa to 32.1 MPa, flow temperatures ranging from 50°C to 502°C and for discharge pressures from 0.1 MPa to 3.6 MPa. Obtained data are compared with the data given in

  3. Experimental study of infrared filaments under different initial conditions

    NASA Astrophysics Data System (ADS)

    Mirell, Daniel Joseph

    field that gives birth to multiphoton and avalanche ionization), (b) conical emission/supercontinuum generation, and (c) emitted THz radiation. The aim of all of this research is to gain a better understanding of filamentation so that we may learn how to control them for the applications of: (a) laser-induced lightning, (b) laser-induced breakdown spectroscopy, (c) LIDAR, (d) medical imaging and many more. In this dissertation we will focus on an experimental study of filamentation in air produced by 780 nm radiation, pulsewidths of 200 fs, and energies pulse of 9 mJ/pulse. We have used an aerodynamic window + vacuum system to study the difference between focusing filament forming pulses down initially in vacuum conditions to that where it is allowed to focus in atmosphere. Described herein is a new way to use an off-the-shelf, inexpensive and robust 1064 nm mirror to observe the beam profile and its evolution in the filament as well as the filaments spectral properties. In addition, experiments to test for the plasma have been conducted. The results of these experiments indicate filament sizes of 200mum, in contrast to the commonly reported value of 100pm. Filaments of this size exist over a length of approximately a meter which is 8 times longer than the associated Rayleigh range for such a spot size with a clear enhancement in filament persistence with the use of the aerodynamic window. In addition the appearance of newly generated "bluer" frequencies that is present under atmospheric focusing is ail but eliminated through an initial focusing of the beam in vacuum conditions. Plasma densities of 1016 e -/cm3 were measured using plasma interferometry.

  4. Transmission rate of African swine fever virus under experimental conditions.

    PubMed

    de Carvalho Ferreira, H C; Backer, J A; Weesendorp, E; Klinkenberg, D; Stegeman, J A; Loeffen, W L A

    2013-08-30

    African swine fever (ASF) is a highly lethal, viral disease of swine. No vaccine is available, so controlling an ASF outbreak is highly dependent on zoosanitary measures, such as stamping out infected herds and quarantining of affected areas. Information on ASF transmission parameters could allow for more efficient application of outbreak control measures. Three transmission experiments were carried out to estimate the transmission parameters of two ASF virus isolates: Malta'78 (in two doses) and Netherlands'86. Different criteria were used for onset of infectiousness of infected pigs and moment of infection of contact pigs. The transmission rate (β), estimated by a Generalized Linear Model, ranged from 0.45 to 3.63 per day. For the infectious period, a minimum as well as a maximum infectious period was determined, to account for uncertainties regarding infectiousness of persistently infected pigs. While the minimum infectious period ranged from 6 to 7 days, the average maximum infectious period ranged from approximately 20 to nearly 40 days. Estimates of the reproduction ratio (R) for the first generation of transmission ranged from 4.9 to 24.2 for the minimum infectious period and from 9.8 to 66.3 for the maximum infectious period, depending on the isolate. A first approximation of the basic reproduction ratio (R0) resulted in an estimate of 18.0 (6.90-46.9) for the Malta'78 isolate. This is the first R0 estimate of an ASFV isolate under experimental conditions. The estimates of the transmission parameters provide a quantitative insight into ASFV epidemiology and can be used for the design and evaluation of more efficient control measures.

  5. Experimental Constraints on He, Ne, Ar Behavior at Mantle Conditions

    NASA Astrophysics Data System (ADS)

    Jackson, C.; Kelley, S. P.; Parman, S. W.; Cooper, R. F.

    2010-12-01

    We have experimentally constrained He, Ne and Ar mineral-melt partitioning for olivine, enstatite and spinel under mantle P-T conditions. The experiments were run in a piston cylinder apparatus. Run products were analyzed by UV laser ablation microprobe (UVLAMP). Our data (Ol, Opx, Sp), along with literature data (Cpx), suggest He, Ne and Ar are incompatible during mantle melting. Gem quality crystals of En100, Sp and Fo90 were polished using colloidal silica and loaded along with a MgO rich, synthetic MORB powder into a graphite inner and Pt outer capsule. Within the inner capsule, crystals were faced against graphite, an identical crystal or polished glassy carbon. Equal pressures (40-60 total bars) of He, Ne and Ar were loaded into the outer capsule before it was welded closed. The run conditions were 1450C and 1-2 GPa for 10 hrs (Brown University). Depth profiles of the mineral faces were obtained using a 193 nm excimer laser (Open University). The large crystal area and short wavelength laser allows for measurements with high depth resolution and concentration precision: a 400 um aperture with 150 nm ablation depth can provide a detection limit (3 sigma > blank) of ~500 ppb He, ~1 ppm Ne and ~500 ppb Ar. Three mineral ablation pits were imaged using a white light interferometer at Tufts University and indicate an ablation rate of ~25 nm/pulse. Glass ablation rates are estimated using previous measurements. The melts were generally understaturated with respect to He, Ne and Ar (1-10, 3-200 and 4-1000 PPM, respectively). Concentrations in the minerals were mostly below detection limits. Where detectable, near surface gas concentrations visually correlate with the amount of adhering graphite. This could be due to trapped/adsorbed gas in the graphite or to surface deformation produced by the graphite. The surface with the least adhering graphite and smoothest surface (faced against glassy carbon) shows no observable near surface enrichment of He, Ne or Ar. Given

  6. Phase Distribution Phenomena for Simulated Microgravity Conditions: Experimental Work

    NASA Technical Reports Server (NTRS)

    Singhal, Maneesh; Bonetto, Fabian J.; Lahey, R. T., Jr.

    1996-01-01

    This report summarizes the work accomplished at Rensselaer to study phase distribution phenomenon under simulated microgravity conditions. Our group at Rensselaer has been able to develop sophisticated analytical models to predict phase distribution in two-phase flows under a variety of conditions. These models are based on physics and data obtained from carefully controlled experiments that are being conducted here. These experiments also serve to verify the models developed.

  7. Phase Distribution Phenomena for Simulated Microgravity Conditions: Experimental Work

    NASA Technical Reports Server (NTRS)

    Singhal, Maneesh; Bonetto, Fabian J.; Lahey, R. T., Jr.

    1996-01-01

    This report summarizes the work accomplished at Rensselaer to study phase distribution phenomenon under simulated microgravity conditions. Our group at Rensselaer has been able to develop sophisticated analytical models to predict phase distribution in two-phase flows under variety of conditions. These models are based on physics and data obtained from carefully controlled experiments that are being conducted here. These experiments also serve to verify the models developed.

  8. Analysis of transcriptional responses of normalizing genes on Crassostrea brasiliana under different experimental conditions.

    PubMed

    Müller, Gabrielle do Amaral E Silva; de Lima, Daína; Zacchi, Flávia Lucena; Piazza, Rômi Sharon; Lüchmann, Karim Hahn; Mattos, Jacó Joaquim; Schlenk, Daniel; Bainy, Afonso Celso Dias

    2017-02-04

    Bivalves show remarkable plasticity to environmental changes and have been proposed as sentinel organisms in biomonitoring. Studies related to transcriptional analysis using quantitative real-time PCR (qRT-PCR) in these organisms have notably increased, imposing a need to identify and validate adequate reference genes for an accurate and reliable analysis. In the present study, nine reference genes were selected from transcriptome data of Crassostrea brasiliana in order to identify their suitability as qRT-PCR normalizer genes. The transcriptional patterns were analyzed in gills of oysters under three different conditions: different temperatures (18°C, 24°C or 32°C) and phenanthrene (PHE) (100 µg.L(-1) ) combined exposure; different salinities (10, 25 or 35 ‰) and PHE combined exposure and 10% of diesel fuel water-accommodated fraction (diesel-WAF) exposure. Reference gene stability was calculated using five algorithms (geNorm, NormFinder, BestKeeper, ΔCt, RefFinder). Transcripts of ankyrin-like (ANK), GAPDH-like and α tubulin-like (TUBA) genes showed minor changes in different temperature/PHE treatment. Transcripts of ANK, β actin-like and β tubulin-like genes showed better stability at salinity/PHE treatment, and ANK, TUBA and 28S ribosomal protein-like genes showed the most stable transcription pattern in oysters exposed to diesel-WAF exposure. This study constitutes the first systematic analysis on reference gene selection for qRT-PCR normalization in C. brasiliana. These genes could be employed in studies using qRT-PCR analysis under similar experimental conditions. This article is protected by copyright. All rights reserved.

  9. Experimental characterization of hohlraum conditions by X-ray spectroscopy

    SciTech Connect

    Back, C.A.; Hsieh, E.J.; Kauffman, R.L.

    1996-06-01

    Spectroscopy is a powerful technique used to measure the plasma parameters relevant to Inertial Confinement Fusion (ICF) plasmas. For instance, the onset of spectral signals from multilayer targets have been used to determine ablation rate scalings. Temperature and density measurements in coronal plasmas have enabled the study of laser coupling efficiency as a function of the laser wavelengths. More recently, dopants have been successfully used to determine capsule conditions of ICF targets. However, few spectroscopic studies have been performed to diagnose plasma conditions of the hohlraum itself. Several laboratories have studied enclosed cavities, previously concentrating on measurements of the radiative heat wave, the x-ray conversion efficiency, and temporal evolution of Au x rays. Measurements of electron temperature T{sub e} and electron densities n{sub e} are difficult because many physical processes occur and each diagnostic`s line-of-sight is restricted by the hohlraum wall. However, they are worth pursuing because they can provide critical information on the target energetics and the evolution of plasma parameters important to achieving fusion. Here the authors discuss spectroscopic tracers to diagnose plasma conditions in the hohlraum, using time- and space-resolved measurements. The tracers are typically mid-Z elements which are placed on the hohlraum wall or supended in the hohlraum volume. To demonstrate the breadth of measurements that can be performed, three types of experiments are presented.

  10. Experimental characterization of materials subjected to combined loading conditions

    NASA Astrophysics Data System (ADS)

    Andrusca, L.; Goanta, V.; Barsanescu, P. D.; Savin, A.

    2016-08-01

    In real life experience, machine and structure elements are subjected to complex loading history. Combined loading testes facilitate the understanding of materials behavior subjected to multiaxial stress state. In this paper are presented experimental investigations used to evaluate the influence of an initial type of loading on material properties which will be subsequently tested through another load type. Initial tests are tension tests, by different elongations, and subsequent tests are torsion tests, until break. Circular cross section specimens will be used in these tests. Tension tests have been performed on a universal testing machine. Subsequently torsion tests have been conducted through an attachable device. It was found that the energy associated with plastic deformation obtained by subsequent torsional tests has the dominant influence on the material total plastic energy, although initial test was tension.

  11. Podocyte hypertrophy precedes apoptosis under experimental diabetic conditions.

    PubMed

    Lee, Sun Ha; Moon, Sung Jin; Paeng, Jisun; Kang, Hye-Young; Nam, Bo Young; Kim, Seonghun; Kim, Chan Ho; Lee, Mi Jung; Oh, Hyung Jung; Park, Jung Tak; Han, Seung Hyeok; Yoo, Tae-Hyun; Kang, Shin-Wook

    2015-08-01

    Podocyte hypertrophy and apoptosis are two hallmarks of diabetic glomeruli, but the sequence in which these processes occur remains a matter of debate. Here we investigated the effects of inhibiting hypertrophy on apoptosis, and vice versa, in both podocytes and glomeruli, under diabetic conditions. Hypertrophy and apoptosis were inhibited using an epidermal growth factor receptor inhibitor (PKI 166) and a pan-caspase inhibitor (zAsp-DCB), respectively. We observed significant increases in the protein expression of p27, p21, phospho-eukaryotic elongation factor 4E-binding protein 1, and phospho-p70 S6 ribosomal protein kinase, in both cultured podocytes exposed to high-glucose (HG) medium, and streptozotocin-induced diabetes mellitus (DM) rat glomeruli. These increases were significantly inhibited by PKI 166, but not by zAsp-DCB. In addition, the amount of protein per cell, the relative cell size, and the glomerular volume were all significantly increased under diabetic conditions, and these changes were also blocked by treatment with PKI 166, but not zAsp-DCB. Increased protein expression of cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase, together with increased Bax/Bcl-2 ratios, were also observed in HG-stimulated podocytes and DM glomeruli. Treatment with either zAsp-DCB or PKI 166 resulted in a significant attenuation of these effects. Both PKI 166 and zAsp-DCB also inhibited the increase in number of apoptotic cells, as assessed by Hoechst 33342 staining and TUNEL assay. Under diabetic conditions, inhibition of podocyte hypertrophy results in attenuated apoptosis, whereas blocking apoptosis has no effect on podocyte hypertrophy, suggesting that podocyte hypertrophy precedes apoptosis.

  12. Uncontrollable atmospheric conditions which can affect animal experimentation.

    PubMed

    Sanz, P; Rodriguez-Vicente, M C; Villar, P; Repetto, M

    1988-10-01

    In our programs of investigation into mechanisms of molecular action of toxic substances, we have had occasion to observe the appearance of anomalous values in biochemical parameters, which we put down to cyclic rhythms or coincidences with the following phenomena: meteorological (storms), geological (earthquakes), and astronomical or phenological (eclipse and lunar phases). This work reviews such observations, which suggest that besides the environmental conditions of the animal room (illumination, humidity, temperature, noise) it is necessary to consider all the external circumstances which occur at the moment of the experiment.

  13. Suitability of MEMS Accelerometers for Condition Monitoring: An experimental study

    PubMed Central

    Albarbar, Alhussein; Mekid, Samir; Starr, Andrew; Pietruszkiewicz, Robert

    2008-01-01

    With increasing demands for wireless sensing nodes for assets control and condition monitoring; needs for alternatives to expensive conventional accelerometers in vibration measurements have been arisen. Micro-Electro Mechanical Systems (MEMS) accelerometer is one of the available options. The performances of three of the MEMS accelerometers from different manufacturers are investigated in this paper and compared to a well calibrated commercial accelerometer used as a reference for MEMS sensors performance evaluation. Tests were performed on a real CNC machine in a typical industrial environmental workshop and the achieved results are presented. PMID:27879734

  14. Suitability of MEMS Accelerometers for Condition Monitoring: An experimental study.

    PubMed

    Albarbar, Alhussein; Mekid, Samir; Starr, Andrew; Pietruszkiewicz, Robert

    2008-02-06

    With increasing demands for wireless sensing nodes for assets control and condition monitoring; needs for alternatives to expensive conventional accelerometers in vibration measurements have been arisen. Micro-Electro Mechanical Systems (MEMS) accelerometer is one of the available options. The performances of three of the MEMS accelerometers from different manufacturers are investigated in this paper and compared to a well calibrated commercial accelerometer used as a reference for MEMS sensors performance evaluation. Tests were performed on a real CNC machine in a typical industrial environmental workshop and the achieved results are presented.

  15. Experimental study on neptunium migration under in situ geochemical conditions

    NASA Astrophysics Data System (ADS)

    Kumata, M.; Vandergraaf, T. T.

    1998-12-01

    Results are reported for migration experiments performed with Np under in situ geochemical conditions over a range of groundwater flow rates in columns of crushed rock in a specially designed facility at the 240-level of the Underground Research Laboratory (URL) near Pinawa, Manitoba, Canada. This laboratory is situated in an intrusive granitic rock formation, the Lac du Bonnet batholith. Highly altered granitic rock and groundwater were obtained from a major subhorizontal fracture zone at a depth of 250 m in the URL. The granite was wet-crushed and wet-sieved with groundwater from this fracture zone. The 180-850-μm size fraction was selected and packed in 20-cm long, 2.54-cm in diameter Teflon™-lined stainless steel columns. Approximately 30-ml vols of groundwater containing 3HHO and 237Np were injected into the columns at flow rates of 0.3, 1, and 3 ml/h, followed by elution with groundwater, obtained from the subhorizontal fracture, at the same flow rates, for a period of 95 days. Elution profiles for 3HHO were obtained, but no 237Np was detected in the eluted groundwater. After terminating the migration experiments, the columns were frozen, the column material was removed and cut into twenty 1-cm thick sections and each section was analyzed by gamma spectrometry. Profiles of 237Np were obtained for the three columns. A one-dimensional transport model was fitted to the 3HHO breakthrough curves to obtain flow parameters for this experiment. These flow parameters were in turn applied to the 237Np concentration profiles in the columns to produce sorption and dispersion coefficients for Np. The results show a strong dependence of retardation factors ( Rf) on flow rate. The decrease in the retarded velocity of the neptunium ( Vn) varied over one order of magnitude under the geochemical conditions for these experiments.

  16. Heterogeneous photocatalytic degradation of gallic acid under different experimental conditions.

    PubMed

    Quici, Natalia; Litter, Marta I

    2009-07-01

    UV/TiO(2)-heterogeneous photocatalysis was tested as a process to degrade gallic acid (Gal) in oxygenated solutions at pH 3. In the absence of oxidants other than oxygen, decay followed a zero order rate at different concentrations and was slow at concentrations higher than 0.5 mM. Addition of Fe(3+), H(2)O(2) and the combination Fe(3+)/H(2)O(2) improved Gal degradation. In the absence of H(2)O(2), an optimal Fe : Gal molar ratio of 0.33 : 1 was found for the photocatalytic decay, beyond which addition of Fe(3+) was detrimental and even worse in comparison with the system in the absence of Fe(3+). TiO(2) addition was beneficial compared with the same system in the absence of the photocatalyst if Fe(3+) was added at low concentration (0.33 : 1 Fe : Gal molar ratio), while at high concentration (1 : 1 Fe : Gal molar ratio) TiO(2) did not exert any significant effect. H(2)O(2) addition (1 : 0.33 Gal : H(2)O(2) molar ratio, absence of Fe(iii)) also enhanced the heterogeneous photocatalytic reaction. Simultaneous addition of Fe(3+) and H(2)O(2) was more effective than the addition of the separate oxidants. This system was compared with Fenton and photo-Fenton systems. At low H(2)O(2) concentration (0.33 : 1 : 0.2 Fe : Gal : H(2)O(2) molar ratio), the presence of TiO(2) also enhanced the reaction. The influence of the thermal charge transfer reaction between Gal and Fe(iii), which leads to an important Gal depletion in the dark with formation of quinones, was analysed. The mechanisms taking place in these complex systems are proposed, paying particular attention to the important charge transfer reaction of the Fe(iii)-Gal complex operative in dark conditions.

  17. 21 CFR 1404.900 - Adequate evidence.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Adequate evidence. 1404.900 Section 1404.900 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 1404.900 Adequate evidence. Adequate evidence means information sufficient...

  18. 21 CFR 1404.900 - Adequate evidence.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Adequate evidence. 1404.900 Section 1404.900 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 1404.900 Adequate evidence. Adequate evidence means information sufficient...

  19. Sip-sizing behaviors in natural drinking conditions compared to instructed experimental conditions.

    PubMed

    Bennett, Janice W; Van Lieshout, Pascal H H M; Pelletier, Cathy A; Steele, Catriona M

    2009-06-01

    To understand disordered physiology, it is first necessary to determine what constitutes normal function. Liquid sip size during swallowing in healthy individuals has been investigated with varied results. Bolus size is a variable that is manipulated in both research studies and clinical swallowing assessments, so defining normal sip size has relevance in both domains. This study looked at sip size under instruction in experimental tasks and compared it to sip size in free drinking while participants were unaware that drinking was being observed. A statistically significant difference was found in water sip volume between natural drinking (mean = 16 ml) and instructed experimental drinking tasks (mean = 6.6-6.8 ml). This difference far exceeded the magnitude of sip-size variation observed between instructed drinking tasks using different stimuli and as a function of participant's gender or age group.

  20. Differences in Active Avoidance Conditioning in Male and Female Rats with Experimental Anxiety-Depressive Disorder.

    PubMed

    Khlebnikova, N N; Krupina, N A; Kushnareva, E Yu; Orlova, I N

    2015-07-01

    Using rat model of experimental anxiety-depressive disorder caused by postnatal administration of methionyl-2(S)-cyanopyrrolidine, an inhibitor of dipeptidyl peptidase IV, we compared conditioned active avoidance response and memory retention in males and females. In experimental males and females, conditioning was impaired in comparison with the control. In experimental groups, females were worse learners than males, while in control groups, females were better learners than males. Memory retention in experimental animals did not differ from that in controls 24 h after learning. Two months after learning, control females demonstrated better retention than control males.

  1. 14 CFR 437.13 - Additional experimental permit terms and conditions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Additional experimental permit terms and conditions. 437.13 Section 437.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING EXPERIMENTAL PERMITS General Information §...

  2. 14 CFR 437.13 - Additional experimental permit terms and conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Additional experimental permit terms and conditions. 437.13 Section 437.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING EXPERIMENTAL PERMITS General Information §...

  3. 14 CFR 437.13 - Additional experimental permit terms and conditions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Additional experimental permit terms and conditions. 437.13 Section 437.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING EXPERIMENTAL PERMITS General Information §...

  4. 14 CFR 437.13 - Additional experimental permit terms and conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Additional experimental permit terms and conditions. 437.13 Section 437.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING EXPERIMENTAL PERMITS General Information §...

  5. 14 CFR 437.13 - Additional experimental permit terms and conditions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Additional experimental permit terms and conditions. 437.13 Section 437.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING EXPERIMENTAL PERMITS General Information §...

  6. 5 CFR 919.900 - Adequate evidence.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Adequate evidence. 919.900 Section 919.900 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 919.900 Adequate...

  7. Conditions for the validity of Faraday's law of induction and their experimental confirmation

    NASA Astrophysics Data System (ADS)

    López-Ramos, A.; Menéndez, J. R.; Piqué, C.

    2008-09-01

    This paper, as its main didactic objective, shows the conditions needed for the validity of Faraday's law of induction. Inadequate comprehension of these conditions has given rise to several paradoxes about the issue; some are analysed and solved in this paper in the light of the theoretical deduction of the induction law. Furthermore, an experimental set-up, in which such conditions are experimentally tested, is included. The experiment is not complicated and the method we use, and similar methods used elsewhere, is widely considered as suitable laboratory practice for students of first university courses in physics and engineering.

  8. Doppler-broadened NICE-OHMS beyond the cavity-limited weak absorption condition - II: Experimental verification

    NASA Astrophysics Data System (ADS)

    Hausmaninger, Thomas; Silander, Isak; Ma, Weiguang; Axner, Ove

    2016-01-01

    Doppler-broadened (Db) noise-immune cavity-enhanced optical heterodyne molecular spectrometry (NICE-OHMS) is normally described by an expression, here termed the conventional (CONV) description, that is restricted to the conventional cavity-limited weak absorption condition (CCLWA), i.e. when the single pass absorbance is significantly smaller than the empty cavity losses, i.e. when α0 L < < π / F. To describe NICE-OHMS signals beyond this limit two simplified extended descriptions (termed the extended locking and extended transmission description, ELET, and the extended locking and full transmission description, ELFT), which are assumed to be valid under the relaxed cavity-limited weak absorption condition (RCLWA), i.e. when α0 L < π / F, and a full description (denoted FULL), presumed to be valid also when the α0 L < π / F condition does not hold, have recently been derived in an accompanying work (Ma W, et al. Doppler-broadened NICE-OHMS beyond the cavity-limited weak absorption condition - I. Theoretical Description. J Quant Spectrosc Radiat Transfer, 2015, http://dx.doi.org/10.1016/j.jqsrt.2015.09.007). The present work constitutes an experimental verification and assessment of the validity of these, performed in the Doppler limit for a set of Fα0 L / π values (up to 3.5); it is shown under which conditions the various descriptions are valid. It is concluded that for samples with Fα0 L / π up to 0.01, all descriptions replicate the data well. It is shown that the CONV description is adequate and provides accurate assessments of the signal strength (and thereby the analyte concentration) up to Fα0 L / π of around 0.1, while the ELET is accurate for Fα0 L / π up to around 0.3. The ELFT description mimics the Db NICE-OHMS signal well for Fα0 L / π up to around unity, while the FULL description is adequate for all Fα0 L / π values investigated. Access to these descriptions both increases considerably the dynamic range of the technique and

  9. Detectors for Linear Colliders: Physics Requirements and Experimental Conditions (1/4)

    ScienceCinema

    None

    2016-07-12

    How is the anticipated physics program of a future e+e- collider shaping the R&D; for new detectors in collider particle physics ? This presentation will review the main physics requirements and experimental conditions comparing to LHC and LEP. In particular, I shall discuss how e+e- experimentation is expected to change moving from LEP-2 up to multi-TeV energies.

  10. Experimental observation of dynamic ductile damage development of Cu under various triaxiality conditions

    NASA Astrophysics Data System (ADS)

    Pillon, Laurianne; Adolf, Lise-Marie

    2017-01-01

    Assuming it is controlled by its plastic behavior, the Gurson model aims at describing damage development in a porous ductile material. It has been extended by Perrin to describe damage evolution in ductile viscoplastic porous materials. The so-called Gurson-Perrin model (GPm) allows representing damage development with respect to stress triaxiality and strain-rate conditions. We propose a new experimental design able to test and validate the GPm under various dynamic conditions and for different triaxiality levels. The principle of this experimental project will be detailed in this paper. An analysis of its results and a comparison with numerical simulations will be presented.

  11. Measurement of acoustic dissipation in an experimental combustor under representative conditions

    NASA Astrophysics Data System (ADS)

    Webster, Samuel; Hardi, Justin; Oschwald, Michael

    2017-03-01

    The present paper is concerned with experimental estimation of acoustic dissipation under conditions representative of those in a rocket engine combustion chamber. Specifically, the influence of operating and injection conditions on acoustic dissipation is considered. Two experimental and analytical techniques are applied to measure and then compare dissipation rates of the first longitudinal and transverse acoustic modes in an experimental combustion chamber. Comparison between non-combustion and combustion tests showed that combustion chamber damping for the first transverse mode is far greater under combustion conditions. A lesser difference between non-combustion and combustion tests for the first longitudinal mode was found although the damping rates during combustion tests were still higher. A strong relationship between primary injection velocity and dissipation rate was observed, with lower injection velocities leading to decreased damping rates of the first transverse mode. Furthermore, increased film cooling injection rate decreased dissipation rate. The significant influence of representative conditions, specifically injection conditions, on dissipation rate has strong implications for both combustor design and experimental approaches aimed at quantifying dissipation in rocket combustion chambers.

  12. A new experimental method for in situ corrosion monitoring under alternate wet-dry conditions.

    PubMed

    Fu, Xinxin; Dong, Junhua; Han, Enhou; Ke, Wei

    2009-01-01

    A new experimental method was applied in in situ corrosion monitoring of mild steel Q235 under alternate wet-dry conditions. The thickness of the electrolyte film during the wet cycle was monitored by a high-precision balance with a sensibility of 0.1 mg. At the same time, an electrochemical impedance technique was employed to study the effect of film thickness on corrosion rates. Experimental results showed that there was a critical electrolyte film condition for which the corrosion rate reached a maximum during wet-dry cycles. For the substrate, the critical condition could be described by a film thickness of about 17 μm. For the rusted specimen, the critical condition could be described by an electrolyte amount of about 0.038 g, which is equivalent to a film thickness of 38 μm. This monitoring system was very useful for studying atmospheric corrosion of metals covered by corrosion products.

  13. Regulatory requirements for providing adequate veterinary care to research animals.

    PubMed

    Pinson, David M

    2013-09-01

    Provision of adequate veterinary care is a required component of animal care and use programs in the United States. Program participants other than veterinarians, including non-medically trained research personnel and technicians, also provide veterinary care to animals, and administrators are responsible for assuring compliance with federal mandates regarding adequate veterinary care. All program participants therefore should understand the regulatory requirements for providing such care. The author provides a training primer on the US regulatory requirements for the provision of veterinary care to research animals. Understanding the legal basis and conditions of a program of veterinary care will help program participants to meet the requirements advanced in the laws and policies.

  14. QEEG Spectral and Coherence Assessment of Autistic Children in Three Different Experimental Conditions

    ERIC Educational Resources Information Center

    Machado, Calixto; Estévez, Mario; Leisman, Gerry; Melillo, Robert; Rodríguez, Rafael; DeFina, Phillip; Hernández, Adrián; Pérez-Nellar, Jesús; Naranjo, Rolando; Chinchilla, Mauricio; Garófalo, Nicolás; Vargas, José; Beltrán, Carlos

    2015-01-01

    We studied autistics by quantitative EEG spectral and coherence analysis during three experimental conditions: basal, watching a cartoon with audio (V-A), and with muted audio band (VwA). Significant reductions were found for the absolute power spectral density (PSD) in the central region for delta and theta, and in the posterior region for sigma…

  15. [Effect of phenibut on the behavior of experimental animals under conditions of voluntary chronic alcoholism].

    PubMed

    Tiurenkov, I N; Voronkov, A V; Borodkina, L E

    2005-01-01

    The effect of phenibut on the locomotor and orientation-research activity, as well as on the alcohol and food motivation, was studied on experimental animals under conditions of voluntary chronic alcoholism. Phenibut decreased the manifestations of alcohol-induced behavioral disorders and reduced alcohol motivation.

  16. Experimental and Theoretical Determination of Heavy Oil Viscosity Under Reservoir Conditions

    SciTech Connect

    Gabitto, Jorge; Barrufet, Maria

    2002-03-11

    The main objective of this research was to propose a simple procedure to predict heavy oil viscosity at reservoir conditions as a function of easily determined physical properties. This procedure will avoid costly experimental testing and reduce uncertainty in designing thermal recovery processes.

  17. Uncertain boundary condition Bayesian identification from experimental data: A case study on a cantilever beam

    NASA Astrophysics Data System (ADS)

    Ritto, T. G.; Sampaio, R.; Aguiar, R. R.

    2016-02-01

    In many mechanical applications (wind turbine tower, substructure joints, etc.), the stiffness of the boundary conditions is uncertain and might decrease with time, due to wear and/or looseness. In this paper, a torsional stiffness parameter is used to model the clamped side of a Timoshenko beam. The goal is to perform the identification with experimental data. To represent the decreasing stiffness of the clamped side, an experimental test rig is constructed, where several rubber layers are added to the clamped side, making it softer. Increasing the number of layers decreases the stiffness, thus representing a loss in the stiffness. The Bayesian approach is applied to update the probabilistic model related to the boundary condition (torsional stiffness parameter). The proposed Bayesian strategy worked well for the problem analyzed, where the experimental natural frequencies were within the 95% confidence limits of the computed natural frequencies probability density functions.

  18. Asbestos/NESHAP adequately wet guidance

    SciTech Connect

    Shafer, R.; Throwe, S.; Salgado, O.; Garlow, C.; Hoerath, E.

    1990-12-01

    The Asbestos NESHAP requires facility owners and/or operators involved in demolition and renovation activities to control emissions of particulate asbestos to the outside air because no safe concentration of airborne asbestos has ever been established. The primary method used to control asbestos emissions is to adequately wet the Asbestos Containing Material (ACM) with a wetting agent prior to, during and after demolition/renovation activities. The purpose of the document is to provide guidance to asbestos inspectors and the regulated community on how to determine if friable ACM is adequately wet as required by the Asbestos NESHAP.

  19. Failure of the Ingard-Myers boundary condition for a lined duct: an experimental investigation.

    PubMed

    Renou, Ygaäl; Aurégan, Yves

    2011-07-01

    This paper deals with experimental investigation of the lined wall boundary condition in flow duct applications such as aircraft engine systems or automobile mufflers. A first experiment, based on a microphone array located in the liner test section, is carried out in order to extract the axial wavenumbers with the help of an "high-accurate" singular value decomposition Prony-like algorithm. The experimental axial wavenumbers are then used to provide the lined wall impedance for both downstream and upstream acoustic propagation by means of a straightforward impedance education method involving the classical Ingard-Myers boundary condition. The results show that the Ingard-Myers boundary condition fails to predict with accuracy the acoustic behavior in a lined duct with flow. An effective lined wall impedance, valid whatever the direction of acoustic propagation, can be suitably found from experimental axial wavenumbers and a modified version of the Ingard-Myers condition with the form inspired from a previous theoretical study [Aurégan et al., J. Acoust. Soc. Am. 109, 59-64 (2001)]. In a second experiment, the scattering matrix of the liner test section is measured and is then compared to the predicted scattering matrix using the multimodal approach and the lined wall impedances previously deduced. A large discrepancy is observed between the measured and the predicted scattering coefficients that confirms the poor accuracy provided from the Ingard-Myers boundary condition widely used in lined duct applications.

  20. Experimental investigation on performance of ice storage air-conditioning system with separate heat pipe

    SciTech Connect

    Fang, Guiyin; Liu, Xu; Wu, Shuangmao

    2009-11-15

    An experimental study on operation performance of ice storage air-conditioning system with separate helical heat pipe is conducted in this paper. The experimental system of ice storage air-conditioning system with separate heat pipe is set up. The performance parameters such as the evaporation pressure and the condensation pressure of refrigeration system, the refrigeration capacity and the COP (coefficient of performance) of the system, the IPF (ice packing factor) and the cool storage capacity in the cool storage tank during charging period, and the cool discharge rate and the cool discharge capacity in the cool storage tank, the outlet water temperature in the cool storage tank and the outlet air temperature in room unit during discharging period are investigated. The experimental results show that the ice storage air-conditioning system with separate helical heat pipe can stably work during charging and discharging period. This indicates that the ice storage air-conditioning system with separate helical heat pipe is well adapted to cool storage air-conditioning systems in building. (author)

  1. Anatomic and Functional Connectivity Relationship in Autistic Children During Three Different Experimental Conditions.

    PubMed

    Machado, Calixto; Rodríguez, Rafael; Estévez, Mario; Leisman, Gerry; Melillo, Robert; Chinchilla, Mauricio; Portela, Liana

    2015-10-01

    A group of 21 autistic children were studied for determining the relationship between the anatomic (AC) versus functional (FC) connectivity, considering short-range and long-range brain networks. AC was assessed by the DW-MRI technique and FC by EEG coherence calculation, in three experimental conditions: basal, watching a popular cartoon with audio (V-A), and with muted audio track (VwA). For short-range connections, basal records, statistical significant correlations were found for all EEG bands in the left hemisphere, but no significant correlations were found for fast EEG frequencies in the right hemisphere. For the V-A condition, significant correlations were mainly diminished for the left hemisphere; for the right hemisphere, no significant correlations were found for the fast EEG frequency bands. For the VwA condition, significant correlations for the rapid EEG frequencies mainly disappeared for the right hemisphere. For long-range connections, basal records showed similar correlations for both hemispheres. For the right hemisphere, significant correlations incremented to all EEG bands for the V-A condition, but these significant correlations disappeared for the fast EEG frequencies in the VwA condition. It appears that in a resting-state condition, AC is better associated with functional connectivity for short-range connections in the left hemisphere. The V-A experimental condition enriches the AC and FC association for long-range connections in the right hemisphere. This might be related to an effective connectivity improvement due to full video stimulation (visual and auditory). An impaired audiovisual interaction in the right hemisphere might explain why significant correlations disappeared for the fast EEG frequencies in the VwA experimental condition.

  2. Adequate mathematical modelling of environmental processes

    NASA Astrophysics Data System (ADS)

    Chashechkin, Yu. D.

    2012-04-01

    In environmental observations and laboratory visualization both large scale flow components like currents, jets, vortices, waves and a fine structure are registered (different examples are given). The conventional mathematical modeling both analytical and numerical is directed mostly on description of energetically important flow components. The role of a fine structures is still remains obscured. A variety of existing models makes it difficult to choose the most adequate and to estimate mutual assessment of their degree of correspondence. The goal of the talk is to give scrutiny analysis of kinematics and dynamics of flows. A difference between the concept of "motion" as transformation of vector space into itself with a distance conservation and the concept of "flow" as displacement and rotation of deformable "fluid particles" is underlined. Basic physical quantities of the flow that are density, momentum, energy (entropy) and admixture concentration are selected as physical parameters defined by the fundamental set which includes differential D'Alembert, Navier-Stokes, Fourier's and/or Fick's equations and closing equation of state. All of them are observable and independent. Calculations of continuous Lie groups shown that only the fundamental set is characterized by the ten-parametric Galilelian groups reflecting based principles of mechanics. Presented analysis demonstrates that conventionally used approximations dramatically change the symmetries of the governing equations sets which leads to their incompatibility or even degeneration. The fundamental set is analyzed taking into account condition of compatibility. A high order of the set indicated on complex structure of complete solutions corresponding to physical structure of real flows. Analytical solutions of a number problems including flows induced by diffusion on topography, generation of the periodic internal waves a compact sources in week-dissipative media as well as numerical solutions of the same

  3. Experimental results for improving the matrix condition using a hybrid optical system.

    PubMed

    Klapp, Iftach; Mendlovic, David

    2012-03-01

    We present preliminary experimental results for implementing the "blurred trajectories" method on three parallel optics (PO) systems. The "main" system and "auxiliary" optics were simple laboratory graded lenses attached to an iris diaphragm. When applying the blurred trajectories method we first show an improvement in the matrix condition, as the matrix condition number decreased in a range of factors of 3 to 418 relative to the main system. Following that, image restoration by weak regularization was performed so that the system matrix condition dominated the restoration process. It was shown that the restoration results of the PO are better than those of the main system and the auxiliary optics separately. In addition, the quality of the restoration follows the system's matrix condition. The improvement in the matrix condition achieved by the PO system improved the immunity to detection noise. Finally, a comparison to Wiener filtering restoration shows that it is also generally inferior to the proposed method.

  4. Funding the Formula Adequately in Oklahoma

    ERIC Educational Resources Information Center

    Hancock, Kenneth

    2015-01-01

    This report is a longevity, simulational study that looks at how the ratio of state support to local support effects the number of school districts that breaks the common school's funding formula which in turns effects the equity of distribution to the common schools. After nearly two decades of adequately supporting the funding formula, Oklahoma…

  5. The effect of nasal speaking valve on the speech under experimental velopharyngeal incompetence condition.

    PubMed

    Suwaki, M; Nanba, K; Ito, E; Kumakura, I; Minagi, S

    2008-05-01

    Velopharyngeal incompetence (VPI) is a contributing factor to speech disorders, frequently accompanying disorders, such as cleft palate, congenital paralysis of the soft palate, and cerebrovascular disease. For the treatment of these types of dysarthria, a Nasal Speaking Valve (NSV), which regulates nasal emission utilizing one-way valve, has been reported to be effective. As the unpleasantness while wearing the NSV was less than that with the conventional Palatal Lift Prosthesis, the NSV could be worn for a longer period of time. As NSV is inserted into the nostrils, this device could easily be provided for edentulous patients. This study aimed to evaluate the effect of NSV on experimentally induced VPI condition. Intelligibility of monosyllabic speech, intelligibility of conversational speech, nasalance score and acoustic analysis were used to evaluate the effect of NSV. Local infiltration anaesthesia was achieved to the area of levator veli palatini muscle and tensor veli palatine muscle of seven adult male subjects. In all subjects, remarkable suppression of the soft palate movement could be observed after the local infiltration anesthesia. Although the utterance supported by NSV under the experimentally induced VPI condition was less natural than the normal utterance, the intelligibility was markedly improved by the device. From the results of this study, the acoustic properties of NSV on the pure VPI condition, which was enabled by the newly established experimental induction, were revealed. This experimental model was also proved to provide a basis for the improvement in the treatment modalities for VPI.

  6. Influence of body condition on influenza a virus infection in mallard ducks: Experimental infection data

    USGS Publications Warehouse

    Arsnoe, D.M.; Ip, H.S.; Owen, J.C.

    2011-01-01

    Migrating waterfowl are implicated in the global spread of influenza A viruses (IAVs), and mallards (Anas platyrhynchos) are considered a particularly important IAV reservoir. Prevalence of IAV infection in waterfowl peaks during autumn pre-migration staging and then declines as birds reach wintering areas. Migration is energetically costly and birds often experience declines in body condition that may suppress immune function. We assessed how body condition affects susceptibility to infection, viral shedding and antibody production in wild-caught and captive-bred juvenile mallards challenged with low pathogenic avian influenza virus (LPAIV) H5N9. Wild mallards (n = 30) were separated into three experimental groups; each manipulated through food availability to a different condition level (-20%, -10%, and normal ??5% original body condition), and captive-bred mallards (n = 10) were maintained at normal condition. We found that wild mallards in normal condition were more susceptible to LPAIV infection, shed higher peak viral loads and shed viral RNA more frequently compared to birds in poor condition. Antibody production did not differ according to condition. We found that wild mallards did not differ from captive-bred mallards in viral intensity and duration of infection, but they did exhibit lower antibody titers and greater variation in viral load. Our findings suggest that reduced body condition negatively influences waterfowl host competence to LPAIV infection. This observation is contradictory to the recently proposed condition-dependent hypothesis, according to which birds in reduced condition would be more susceptible to IAV infection. The mechanisms responsible for reducing host competency among birds in poor condition remain unknown. Our research indicates body condition may influence the maintenance and spread of LPAIV by migrating waterfowl. ?? 2011 Arsnoe et al.

  7. Influence of body condition on influenza A virus infection in mallard ducks: Experimental infection data

    USGS Publications Warehouse

    Arsnoe, Dustin M.; Ip, Hon S.; Owen, Jennifer C.

    2011-01-01

    Migrating waterfowl are implicated in the global spread of influenza A viruses (IAVs), and mallards (Anas platyrhynchos) are considered a particularly important IAV reservoir. Prevalence of IAV infection in waterfowl peaks during autumn pre-migration staging and then declines as birds reach wintering areas. Migration is energetically costly and birds often experience declines in body condition that may suppress immune function. We assessed how body condition affects susceptibility to infection, viral shedding and antibody production in wild-caught and captive-bred juvenile mallards challenged with low pathogenic avian influenza virus (LPAIV) H5N9. Wild mallards (n = 30) were separated into three experimental groups; each manipulated through food availability to a different condition level (-20%, -10%, and normal ±5% original body condition), and captive-bred mallards (n = 10) were maintained at normal condition. We found that wild mallards in normal condition were more susceptible to LPAIV infection, shed higher peak viral loads and shed viral RNA more frequently compared to birds in poor condition. Antibody production did not differ according to condition. We found that wild mallards did not differ from captive-bred mallards in viral intensity and duration of infection, but they did exhibit lower antibody titers and greater variation in viral load. Our findings suggest that reduced body condition negatively influences waterfowl host competence to LPAIV infection. This observation is contradictory to the recently proposed condition-dependent hypothesis, according to which birds in reduced condition would be more susceptible to IAV infection. The mechanisms responsible for reducing host competency among birds in poor condition remain unknown. Our research indicates body condition may influence the maintenance and spread of LPAIV by migrating waterfowl.

  8. Experimental study of ice lens formation using fine granular materials under terrestrial and martian conditions

    NASA Astrophysics Data System (ADS)

    Saruya, T.; Rempel, A. W.; Kurita, K.

    2012-12-01

    Detailed exploration of Mars has yielded a range of direct and indirect evidence for the distribution of ice. Significantly, direct observations of segregated ice (i.e. sediment free) were obtained by Phoenix lander. This segregated ice most likely originated as an ice lens, which formed by the migration and solidification of unfrozen water. Unfrozen water that is adsorbed to particle surfaces and confined to capillary regions remains in the liquid state below the normal melting temperature. This water is known to migrate in frozen materials and form ice lenses. Zent et al. (2012) developed a numerical model for ice lens formation (Rempel et al. 2004) and demonstrated that the nucleation of ice lenses at the Phoenix landing site was possible in the recent past. However, many questions remain regarding the detailed conditions of ice lens nucleation and growth, even in the terrestrial environment. Further experimental checks of numerical models are especially needed. Here, we describe laboratory investigations of ice lens behavior under both terrestrial conditions and with experimental conditions approaching those in the martian environment. We have performed a series of step-freezing experiments in fine, granular materials to observe the initiation and growth of ice lenses. Our experiments reveal clear and systematic relationships between ice-lens behavior and the imposed cooling temperature and host particle size. We compared our experimental results to numerical predictions from a model of ice lens formation (Rempel et al. 2004) that was applied to our experimental conditions. We find that the trend is consistent between the experiment and model, however, there are important quantitative differences. Most notably, modeled ice-lens nucleation occurred more quickly and enabled ice lenses to grow larger than occurred during our experiments. We infer that some additional mechanisms must be responsible for restricting the formation and growth of ice lenses. Further

  9. Do conditional cash transfers influence migration? A study using experimental data from the Mexican PROGRESA program.

    PubMed

    Stecklov, Guy; Winters, Paul; Stampini, Marco; Davis, Benjamin

    2005-11-01

    Prior research on Mexican migration has shown that social networks and economic incentives play an important role in determining migration outcomes. We use experimental data from PROGRESA, Mexico's primary poverty-reduction program, to evaluate the effects of conditional cash transfers on migration both domestically and to the United States. Our study complements a growing body of literature aimed at overcoming longstanding hurdles to the establishment of causal validity in empirical studies of migration. Analysis based on the data collected before and after the program's onset shows that conditional transfers reduce U.S. migration but not domestic migration. The data also enable us to explore the role of existing family and community migration networks. The results show that migration networks strongly influence migration, but that the effect of conditional transfers on migration is apparently not mediated by existing migration network structures. Our results suggest that conditional transfers may be helpful in managing rural out-migration, particularly to the United States.

  10. Experimental investigation of panel radiator heat output enhancement for efficient thermal use under actual operating conditions

    NASA Astrophysics Data System (ADS)

    Calisir, Tamer; Baskaya, Senol; Onur Yazar, Hakan; Yucedag, Sinan

    2015-05-01

    In this study the heat output of a panel-convector-convector-panel radiator (PCCP) under controlled laboratory conditions under Turkish household and especially Ankara conditions was investigated experimentally. In this sense, investigations were performed for different heating water mass flow rates, water inlet temperatures and radiator inlet and outlet connection positions, which are most commonly used in Turkey. An experimental setup was built for this purpose in a test room where temperature was controlled and held constant during the experiments. Inlet and outlet water temperatures and mass flow rates were measured and heat output of the radiator was calculated. Infrared thermal camera visualizations of the steel panel radiator front surface were also performed.

  11. Remodeling of chick embryonic ventricular myoarchitecture under experimentally changed loading conditions.

    PubMed

    Sedmera, D; Pexieder, T; Rychterova, V; Hu, N; Clark, E B

    1999-02-01

    Adult myocardium adapts to changing functional demands by hyper- or hypotrophy while the developing heart reacts by hyper- or hypoplasia. How embryonic myocardial architecture adjusts to experimentally altered loading is not known. We subjected the chick embryonic hearts to mechanically altered loading to study its influence upon ventricular myoarchitecture. Chick embryonic hearts were subjected to conotruncal banding (increased afterload model), or left atrial ligation or clipping, creating a combined model of increased preload in right ventricle and decreased preload in left ventricle. Modifications of myocardial architecture were studied by scanning electron microscopy and histology with morphometry. In the conotruncal banded group, there was a mild to moderate ventricular dilatation, thickening of the compact myocardium and trabeculae, and spiraling of trabecular course in the left ventricle. Right atrioventricular valve morphology was altered from normal muscular flap towards a bicuspid structure. Left atrial ligation or clipping resulted in hypoplasia of the left heart structures with compensatory overdevelopment on the right side. Hypoplastic left ventricle had decreased myocardial volume and showed accelerated trabecular compaction. Increased volume load in the right ventricle was compensated primarily by chamber dilatation with altered trabecular pattern, and by trabecular proliferation and thickening of the compact myocardium at the later stages. A ventricular septal defect was noted in all conotruncal banded, and 25% of left atrial ligated hearts. Increasing pressure load is a main stimulus for embryonic myocardial growth, while increased volume load is compensated primarily by dilatation. Adequate loading is important for normal cardiac morphogenesis and the development of typical myocardial patterns.

  12. [Emoxipin pharmacokinetics in normal conditions and in models of experimental pathology].

    PubMed

    Mishina, E V; Filippenko, N G; Pichugin, V V; Zherdev, V P; Lebedev, A V; Kameneva, N V; Shvedova, A A

    1990-10-01

    The experimentally induced infarct and postoperative stress were shown to alter the kinetics of emoxipine consumption revealed in the increase of drug level in the blood. Elimination rate declines resulting in the increase of emoxipine bioavailability. This tendency is especially appreciable during elimination. The high emoxipine concentration appears to be the result of feedback regulation of its delivery from depot. Therefore pathological conditions have a significant effect on pharmacokinetics of emoxipine; this phenomenon seems to intensify the pharmacological action of this drug.

  13. Experimental Investigation of the Effects of Surface Conditions on Natural Convection-Driven Evaporation

    NASA Astrophysics Data System (ADS)

    Bower, S. M.; Saylor, J. R.

    2009-11-01

    Presented are the results from an experimental investigation of the effects of surface conditions at an air/water interface on transport phenomena within the context of natural convection-driven evaporation. Experiments were conducted using tanks of heated water under several different surface conditions: 1) contamination with an oleyl alcohol monolayer, 2) contamination with a stearic acid monolayer, and 3) ``clean'' or surfactant-free. These surface conditions create the following hydrodynamic boundary conditions: 1) constant elasticity, 2) no-slip, and 3) shear-free. The effect of these boundary conditions on evaporation and air-side natural convection heat transfer is presented via the power law relationships between the Sherwood and Rayleigh numbers (for evaporation) and the Nusselt and Rayleigh numbers (for natural convection heat transfer). Additionally, infrared imagery of the water surface was collected during these experiments, yielding qualitative information on the effect of these boundary conditions on the flow near the interface. Few studies exist in which the effects of surface conditions on interfacial heat and mass transfer are investigated, making this work particularly relevant.

  14. Computational modeling and experimental validation of odor detection behaviors of classically conditioned parasitic wasp, Microplitis croceipes.

    PubMed

    Zhou, Zhongkun; Kulasiri, Don; Samarasinghe, Sandhya; Rains, Glen; Olson, Dawn M

    2015-01-01

    A prototype chemical sensor named Wasp hound® that utilizes five classically conditioned parasitoid wasps, Microplitis croceipes (Cresson) (Hymenoptera: Braconidae), to detect volatile odors was successfully implemented in a previous study. To improve the odor-detecting ability of Wasp Hound®, searching behaviors of an individual wasp in a confined area are studied and modeled through stochastic differential equations in this paper. The wasps are conditioned to 20 mg of coffee when associated with food and subsequently, tested to 5, 10, 20, and 40 mg of coffee. A stochastic model is developed and validated based on three positive behavioral responses (walking, rotation around odor source, and self-rotation) from conditioned wasps at four different test dosages. The model is capable to reproducing the behaviors of conditioned wasps, and can be used to improve the ability of Wasp Hound® to assess changes in odor concentration. The model simulation results show the behaviors of conditioned wasps are significantly different when tested at different coffee dosages. We conjecture that the searching behaviors of conditioned wasps are based on the temporal and spatial neuron activity of olfactory receptor neurons and glomeruli, which are strongly correlated to the training dosages. The overall results demonstrate the utility of mathematical models for interpreting experimental observations, gaining novel insights into the dynamic behavior of classically conditioned wasps, as well as broadening the practical uses of Wasp Hound.

  15. Toltrazuril treatment of cystoisosporosis in dogs under experimental and field conditions.

    PubMed

    Daugschies, A; Mundt, H C; Letkova, V

    2000-10-01

    Coccidia of the genus Cystoisospora cause mild to severe diarrhoea in dogs. The effects of toltrazuril treatment on cystoisosporosis were studied under experimental and field conditions. Twenty-four puppies were experimentally infected each with 4 x 10(4) oocysts of the Cystoisospora ohioensis group. Three groups of six puppies were treated 3 dpi with 10, 20 or 30 mg/kg body weight of toltrazuril suspension (5%); the remaining six puppies served as non-treated controls. Toltrazuril suspension or microgranulate were given once in a dose of 10 or 20 mg/kg body weight, respectively, to naturally infected puppies in conventional dog breeding facilities, depending on the coproscopical evidence of infection. Oocyst excretion and clinical data were recorded. Under experimental conditions, the non-treated puppies excreted oocysts beginning at 6 dpi and suffered from catarrhalic to haemorrhagic diarrhoea. On 12 dpi, four of six non-treated puppies died. Irrespective of the dose, toltrazuril treatment totally suppressed oocyst excretion and no diarrhoea or other signs of disease were observed in the treated groups. Natural Cystoisospora infections were regularly found during the 3rd or 4th week of age in dog breeding facilities although not always associated with diarrhoea. A single oral application of toltrazuril abrogated oocyst shedding and the treated puppies remained generally coproscopically negative during the following 2-4 weeks. Cystoisospora is pathogenic for puppies and can induce severe disease. Natural infections are common in conventional dog breeding facilities. Toltrazuril treatment is suitable for controlling cystoisosporosis under experimental and field conditions. A single oral treatment for puppies in the 3rd or 4th week of age is recommended.

  16. Quantum versus classical foundation of statistical mechanics under experimentally realistic conditions.

    PubMed

    Reimann, Peter; Evstigneev, Mykhaylo

    2013-11-01

    Focusing on isolated macroscopic systems, described in terms of either a quantum mechanical or a classical model, our two key questions are how far does an initial ensemble (usually far from equilibrium and largely unknown in detail) evolve towards a stationary long-time behavior (equilibration) and how far is this steady state in agreement with the microcanonical ensemble as predicted by statistical mechanics (thermalization). A recently developed quantum mechanical treatment of the problem is briefly summarized, putting particular emphasis on the realistic modeling of experimental measurements and nonequilibrium initial conditions. Within this framework, equilibration can be proven under very weak assumptions about those measurements and initial conditions, while thermalization still requires quite strong additional hypotheses. An analogous approach within the framework of classical mechanics is developed and compared with the quantum case. In particular, the assumptions to guarantee classical equilibration are now rather strong, while thermalization then follows under relatively weak additional conditions.

  17. Experimental challenges to theories of classical conditioning: application of an attentional model of storage and retrieval.

    PubMed

    Schmajuk, Nestor A; Larrauri, José A

    2006-01-01

    Several studies have recently challenged the accuracy of traditional models of classical conditioning that account for some experimental data in terms of a storage deficit. Among other results, it has been reported that extinction of the blocking or overshadowing stimulus results in the recovery of the response to the blocked or overshadowed stimulus, backward blocking shows spontaneous recovery, extinction of the training context results in the recovery from latent inhibition, interposing a delay between conditioning and testing in latent inhibition increases latent inhibition, and latent inhibition antagonizes overshadowing. An existing neural network model of classical conditioning (N. A. Schmajuk, Y. Lam, & J. A. Gray, 1996), which includes an attentional mechanism controlling both storage and retrieval of associations, is able to quantitatively describe these results.

  18. Experimental and numerical investigation of centrifugal pumps with asymmetric inflow conditions

    NASA Astrophysics Data System (ADS)

    Mittag, Sten; Gabi, Martin

    2015-11-01

    Most of the times pumps operate off best point states. Reasons are changes of operating conditions, modifications, pollution and wearout or erosion. As consequences non-rotational symmetric flows, transient operational conditions, increased risk of cavitation, decrease of efficiency and unpredictable wearout can appear. Especially construction components of centrifugal pumps, in particular intake elbows, contribute to this matter. Intake elbows causes additional losses and secondary flows, hence non-rotational velocity distributions as intake profile to the centrifugal pump. As a result the impeller vanes experience permanent changes of the intake flow angle and with it transient flow conditions in the blade channels. This paper presents the first results of a project, experimentally and numerically investigating the consequences of non-rotational inflow to leading edge flow conditions of a centrifugal pump. Therefore two pumpintake- elbow systems are compared, by only altering the intake elbow geometry: a common single bended 90° elbow and a numerically optimized elbow (improved regarding rotational symmetric inflow conditions and friction coefficient). The experiments are carried out, using time resolved stereoscopic PIV on a full acrylic pump with refractions index matched (RIM) working fluid. This allows transient investigations of the flow field simultaneously for all blade leading edges. Additional CFD results are validated and used to further support the investigation i.e. for comparing an analog pump system with ideal inflow conditions.

  19. Experimental investigation on dependency of Terfenol-D transducers performance on working conditions

    NASA Astrophysics Data System (ADS)

    Sheykholeslami, M.; Hojjat, Y.; Cinquemani, S.; Tarabini, M.; Ghodsi, M.

    2016-04-01

    Performance and efficiency of magnetostrictive transducer are highly dependent on working conditions. Magnetic bias field and pre-stress of the magnetostrictive rod are two of the main factors affecting the transducer behavior. Unexpected changes may cause unpredictable behavior of the transducer and a dramatic loss of performances. This paper experimentally investigates the effect of different working conditions on quality factor, bandwidth, resonance of a Terfenol-D resonance transducer that works in its first mode of vibration. For this purpose, an experimental setup consisting of laser Doppler, power amplifier and current transducer has been used. A Terfenol-D resonance transducer that is capable of changing magnetic bias field and mechanical pre-stress has been designed and fabricated. Working frequency of the transducer is between 5000 Hz to 7000 Hz. Output parameters of the transducer are experimentally calculated using an equivalent electrical circuit model. Results of the study improves the knowledge in the field and gives suggestions to the design of resonance transducers.

  20. Effectiveness of emergency procedures under BDBA-conditions -- Experimental investigations in an integral test facility (PKL)

    SciTech Connect

    Umminger, K.; Kastner, W.; Weber, P.

    1996-07-01

    As part of the German reactor safety program, experimental investigations into the thermal hydraulic behavior of pressurized water reactors (PWRs) under accident conditions have been performed in the PKL test facility by Siemens/KWU. PKL is a mockup of a typical 4-loop 1,300 MWe KWU-PWR, based on a volumetric scale of 1:145 and full-scale component heights. The topic of beyond-design-basis accidents (BDBAs), such as total loss of feedwater, including experimental verification of relevant accident management procedures, was the main subject of interest in the test program PKL III C, which was completed in June 1995. The test results demonstrated that even under extreme boundary conditions, core damage can be prevented by performing accident management procedures. Especially the high efficiency of the secondary side bleed-and-feed, which is the preferred measure according to the accident management concept of German PWR plants, was clearly shown. This paper summarizes the fundamental findings of the PKL III C program, focusing on experimental results concerning the efficiency of secondary side bleed-and-feed procedures during loss of feedwater transients. For completeness additional results regarding this topic from the preceding program 3 B and the first results from the current program III D will be included.

  1. Experimental study of a mixed refrigerant Joule-Thomson cryocooler using a commercial air-conditioning scroll compressor

    NASA Astrophysics Data System (ADS)

    Lee, Jisung; Lee, Kyungsoo; Jeong, Sangkwon

    2013-05-01

    Mixed refrigerant Joule-Thomson (MR J-T) cryocoolers have been used to create cryogenic temperatures and are simple, efficient, cheap, and durable. However, compressors for MR J-T cryocoolers still require optimization. As the MR J-T cryocooler uses a commercial scroll compressor developed for air-conditioning systems, compressor overheating due to the use of less optimized refrigerants may not be negligible, and could cause compressor malfunction due to burn-out of scroll tip seals. Therefore, in the present study, the authors propose procedures to optimize compressor operation to avoid the overheating issue when the MR J-T cryocooler is used with a commercial oil lubricated scroll compressor, and the present experimental results obtained for a MR J-T cryocooler. A single stage 1.49 kW (2 HP) scroll compressor designed for R22 utilizing a mixture of nitrogen and hydrocarbons was used in the present study. As was expected, compressor overheating and irreversible high temperatures at a compressor discharge port were found at the beginning of compressor operation, which is critical, and hence, the authors used a water injection cooling system for the compressor to alleviate temperature overshooting. In addition, a portion of refrigerant in the high-pressure stream was by-passed into the compressor suction port. This allowed an adequate compression ratio, prevented excessive temperature increases at the compressor discharge, and eventually enabled the MR J-T cryocooler to operate stably at 121 K. The study shows that commercial oil lubricated scroll compressors can be used for MR J-T cryocooling systems if care is exercised to avoid compressor overheating.

  2. Application of Response Surface Methodology to Evaluation of Bioconversion Experimental Conditions

    PubMed Central

    Cheynier, Véronique; Feinberg, Max; Chararas, Constantin; Ducauze, Christian

    1983-01-01

    Using Candida tenuis, a yeast isolated from the digestive tube of the larva of Phoracantha semipunctata (Cerambycidae, Coleoptera), we were able to demonstrate the bioconversion of citronellal to citronellol. Response surface methodology was used to achieve the optimization of the experimental conditions for that bioconversion process. To study the proposed second-order polynomial model, we used a central composite experimental design with multiple linear regression to estimate the model coefficients of the five selected factors believed to influence the bioconversion process. Only four were demonstrated to be predominant: the incubation pH, temperature, time, and the amount of substrate. The best reduction yields (close to 90%) were obtained with alkaline pH conditions (pH 7.5), a low temperature (25°C), a small amount of substrate (15 μl), and short incubation time (16 h). This methodology was very efficient: only 36 experiments were necessary to assess these conditions, and model adequacy was very satisfactory as the coefficient of determination was 0.9411. PMID:16346211

  3. Pliocene Model Intercomparison Project (PlioMIP): Experimental Design and Boundary Conditions (Experiment 2)

    NASA Technical Reports Server (NTRS)

    Haywood, A. M.; Dowsett, H. J.; Robinson, M. M.; Stoll, D. K.; Dolan, A. M.; Lunt, D. J.; Otto-Bliesner, B.; Chandler, M. A.

    2011-01-01

    The Palaeoclimate Modelling Intercomparison Project has expanded to include a model intercomparison for the mid-Pliocene warm period (3.29 to 2.97 million yr ago). This project is referred to as PlioMIP (the Pliocene Model Intercomparison Project). Two experiments have been agreed upon and together compose the initial phase of PlioMIP. The first (Experiment 1) is being performed with atmosphere only climate models. The second (Experiment 2) utilizes fully coupled ocean-atmosphere climate models. Following on from the publication of the experimental design and boundary conditions for Experiment 1 in Geoscientific Model Development, this paper provides the necessary description of differences and/or additions to the experimental design for Experiment 2.

  4. Forming Limits in Sheet Metal Forming for Non-Proportional Loading Conditions - Experimental and Theoretical Approach

    SciTech Connect

    Ofenheimer, Aldo; Buchmayr, Bruno; Kolleck, Ralf

    2005-08-05

    The influence of strain paths (loading history) on material formability is well known in sheet forming processes. Sophisticated experimental methods are used to determine the entire shape of strain paths of forming limits for aluminum AA6016-T4 alloy. Forming limits for sheet metal in as-received condition as well as for different pre-deformation are presented. A theoretical approach based on Arrieux's intrinsic Forming Limit Stress Curve (FLSC) concept is employed to numerically predict the influence of loading history on forming severity. The detailed experimental strain paths are used in the theoretical study instead of any linear or bilinear simplified loading histories to demonstrate the predictive quality of forming limits in the state of stress.

  5. Quantitative study on propagation and healing of Airy beams under experimental conditions.

    PubMed

    Zhuang, Fei; Zhu, Ziyi; Margiewicz, Jessica; Shi, Zhimin

    2015-03-01

    We investigate the propagation and healing of Airy beams in two dimensions that are obtainable under practical experimental conditions. We introduce an intensity similarity factor to quantitatively describe how an Airy beam retains its original shape. Based on such a figure of merit, we define a shape-retaining distance to quantify how far an Airy beam can keep the shape of its main lobe upon propagation and a healing distance to quantify how soon an initially partially blocked Airy beam can restore its main lobe profile. We perform an analysis on how these two distances scale with experimental parameters. We further use an interference picture to interpret the healing phenomenon of an Airy beam. Our work can serve as a guideline for quantitative performance analysis for applications of Airy beams and can be extended to other special beams in a straightforward fashion.

  6. Experimental Adiabatic Quantum Factorization under Ambient Conditions Based on a Solid-State Single Spin System.

    PubMed

    Xu, Kebiao; Xie, Tianyu; Li, Zhaokai; Xu, Xiangkun; Wang, Mengqi; Ye, Xiangyu; Kong, Fei; Geng, Jianpei; Duan, Changkui; Shi, Fazhan; Du, Jiangfeng

    2017-03-31

    The adiabatic quantum computation is a universal and robust method of quantum computing. In this architecture, the problem can be solved by adiabatically evolving the quantum processor from the ground state of a simple initial Hamiltonian to that of a final one, which encodes the solution of the problem. Adiabatic quantum computation has been proved to be a compatible candidate for scalable quantum computation. In this Letter, we report on the experimental realization of an adiabatic quantum algorithm on a single solid spin system under ambient conditions. All elements of adiabatic quantum computation, including initial state preparation, adiabatic evolution (simulated by optimal control), and final state read-out, are realized experimentally. As an example, we found the ground state of the problem Hamiltonian S_{z}I_{z} on our adiabatic quantum processor, which can be mapped to the factorization of 35 into its prime factors 5 and 7.

  7. Pliocene Model Intercomparison Project (PlioMIP): experimental design and boundary conditions (Experiment 2)

    USGS Publications Warehouse

    Haywood, A.M.; Dowsett, H.J.; Robinson, M.M.; Stoll, D.K.; Dolan, A.M.; Lunt, D.J.; Otto-Bliesner, B.; Chandler, M.A.

    2011-01-01

    The Palaeoclimate Modelling Intercomparison Project has expanded to include a model intercomparison for the mid-Pliocene warm period (3.29 to 2.97 million yr ago). This project is referred to as PlioMIP (the Pliocene Model Intercomparison Project). Two experiments have been agreed upon and together compose the initial phase of PlioMIP. The first (Experiment 1) is being performed with atmosphere-only climate models. The second (Experiment 2) utilises fully coupled ocean-atmosphere climate models. Following on from the publication of the experimental design and boundary conditions for Experiment 1 in Geoscientific Model Development, this paper provides the necessary description of differences and/or additions to the experimental design for Experiment 2.

  8. Experimental Evidence of Classical Conditioning and Microscopic Engrams in an Electroconductive Material

    PubMed Central

    Karbowski, Lukasz M.; Persinger, Michael A.

    2016-01-01

    Synthetic experimental substrates are indispensable tools which can allow researchers to model biological processes non-invasively in three-dimensional space. In this study, we investigated the capacities of an electroconductive material whose properties converge upon those of the brain. An electrically conductive material composed of carbohydrates, proteins, fats, ions, water, and trace amounts of other organic compounds and minerals was classically conditioned as inferred by electrophysiological measurements. Spectral densities evoked during the display of a conditioned stimulus (CS) probe were strongly congruent with those displayed during the conditioned-unconditioned stimulus pairing (CS-UCS). The neutral stimulus consisted of the pulsed light from a LED. The unconditioned stimulus was an alternating current. Interstimulus intervals >130 ms did not result in conditioned responses. Microscopic analysis of the chemically-fixed substratum revealed 10–200 μm wide ‘vessel structures’ within samples exposed to a stimulus. Greater complexity (increased fractal dimensions) was clearly discernable by light microscopy for stained sections of fixed samples that had been conditioned compared to various controls. The denser pixels indicated greater concentration of stain and increased canalization. Implications for learning and memory formation are discussed. PMID:27764215

  9. Degradation of caffeine by photo-Fenton process: optimization of treatment conditions using experimental design.

    PubMed

    Trovó, Alam G; Silva, Tatiane F S; Gomes, Oswaldo; Machado, Antonio E H; Neto, Waldomiro Borges; Muller, Paulo S; Daniel, Daniela

    2013-01-01

    The degradation of caffeine in different kind of effluents, via photo-Fenton process, was investigated in lab-scale and in a solar pilot plant. The treatment conditions (caffeine, Fe(2+) and H(2)O(2) concentrations) were defined by experimental design. The optimized conditions for each variable, obtained using the response factor (% mineralization), were: 52.0 mg L(-1)caffeine, 10.0 mg L(-1)Fe(2+) and 42.0 mg L(-1)H(2)O(2) (replaced in kinetic experiments). Under these conditions, in ultrapure water (UW), the caffeine concentration reached the quantitation limit (0.76 mg L(-1)) after 20 min, and 78% of mineralization was obtained respectively after 120 min of reaction. Using the same conditions, the matrix influence (surface water - SW and sewage treatment plant effluent - STP) on caffeine degradation was also evaluated. The total removal of caffeine in SW was reached at the same time in UW (after 20 min), while 40 min were necessary in STP. Although lower mineralization rates were verified for high organic load, under the same operational conditions, less H(2)O(2) was necessary to mineralize the dissolved organic carbon as the initial organic load increases. A high efficiency of the photo-Fenton process was also observed in caffeine degradation by solar photocatalysis using a CPC reactor, as well as intermediates of low toxicity, demonstrating that photo-Fenton process can be a viable alternative for caffeine removal in wastewater.

  10. Effect of experimental conditions on surface hardness measurements of calcified tissues via LIBS

    NASA Astrophysics Data System (ADS)

    Abdel-Salam, Z. A.; Nanjing, Z.; Anglos, D.; Harith, M. A.

    2009-01-01

    This paper reports on the effects of LIBS experimental conditions on the measurement of the surface hardness of calcified tissues. The technique mainly depends on a previously demonstrated correlation between the intensity ratio of ionic to atomic spectral lines and the hardness of the target material. Three types of calcified tissues have been examined, namely enamel of human teeth, shells, and eggshells. Laser-induced breakdown spectra were obtained under two different experimental conditions. In the first nano and picoseconds, laser pulses were used in a single-pulse arrangement, while in the second, single- and double-pulse regimes with nanosecond laser excitation were utilized. The results show that the ionic to atomic spectral line intensity ratios are higher in the case of picosecond laser pulse for both Ca and Mg spectral lines. This effect has been justified in view of the repulsive force of the laser-induced shock waves which depends clearly on the target surface hardness and on the laser irradiance. The electron densities ratio (pico/nano) is shown to be strongly depending on the laser irradiance too. In the case of calcium, single-pulse ratios are higher than the double-pulse ratios, while there is no appreciable difference between both in the case of magnesium. The results obtained herein suggest that double-pulse nanosecond arrangement and the choice of a minor element such as Mg furnishes the best experimental conditions for estimating the surface hardness via LIBS spectra. To validate this method, it has been applied on two previously measured groups of teeth enamel, the first is of ancient Egyptians, and the second from Nubians and Ugandans. The results support the usefulness of this method for similar real-life applications.

  11. Deep Boreholes Seals Subjected to High P,T conditions - Proposed Experimental Studies

    NASA Astrophysics Data System (ADS)

    Caporuscio, F.

    2015-12-01

    Deep borehole experimental work will constrain the P,T conditions which "seal" material will experience in deep borehole crystalline rock repositories. The rocks of interest to this study include mafic (amphibolites) and silicic (granitic gneiss) end members. The experiments will systematically add components to capture discrete changes in both water and EBS component chemistries. Experiments in the system wall rock-clay-concrete-groundwater will evaluate interactions among components, including: mineral phase stability, metal corrosion rates and thermal limits. Based on engineered barrier studies, experimental investigations will move forward with three focusses. First, evaluation of interaction between "seal" materials and repository wall rock (crystalline) under fluid-saturated conditions over long-term (i.e., six-month) experiments; which reproduces the thermal pulse event of a repository. Second, perform experiments to determine the stability of zeolite minerals (analcime-wairakitess) under repository conditions. Both sets of experiments are critically important for understanding mineral paragenesis (zeolites and/or clay transformations) associated with "seals" in contact with wall rock at elevated temperatures. Third, mineral growth at the metal interface is a principal control on the survivability (i.e. corrosion) of waste canisters in a repository. The objective of this planned experimental work is to evaluate physio-chemical processes for 'seal' components and materials relevant to deep borehole disposal. These evaluations will encompass multi-laboratory efforts for the development of seals concepts and application of Thermal-Mechanical-Chemical (TMC) modeling work to assess barrier material interactions with subsurface fluids and other barrier materials, their stability at high temperatures, and the implications of these processes to the evaluation of thermal limits.

  12. Method of experimental determination of the kinetic constants in fast polymerization reactions in nonisothermal diffusion conditions

    SciTech Connect

    Prochukhan, Yu.A.; Berlin, A.A.; Enikolopyan, N.S.

    1986-09-01

    A new method for the experimental determination of the kinetic constants k/sub p/ and k/sub t/ in fast polymerization reactions on the example of cationic (under the effect of AlCl/sub 3/, BF/sub 3/, and other catalysts) liquid phase polymerization of isobutylene in a flow was suggested. The study of the macrokinetic features of low-temperature polymerization of isobutylene revealed the specific conditions of the occurrence of the process (quasi-ideal displacement) which are characterized by the relative constancy and uniformity of the distribution of the concentrations of the reacting substances along the flow section.

  13. Experimental investigation of the noise emission of axial fans under distorted inflow conditions

    NASA Astrophysics Data System (ADS)

    Zenger, Florian J.; Renz, Andreas; Becher, Marcus; Becker, Stefan

    2016-11-01

    An experimental investigation on the noise emission of axial fans under distorted inflow conditions was conducted. Three fans with forward-skewed fan blades and three fans with backward-skewed fan blades and a common operating point were designed with a 2D element blade method. Two approaches were adopted to modify the inflow conditions: first, the inflow turbulence intensity was increased by two different rectangular grids and second, the inflow velocity profile was changed to an asymmetric characteristic by two grids with a distinct bar stacking. An increase in the inflow turbulence intensity affects both tonal and broadband noise, whereas a non-uniform velocity profile at the inlet influences mainly tonal components. The magnitude of this effect is not the same for all fans but is dependent on the blade skew. The impact is greater for the forward-skewed fans than for the backward-skewed and thus directly linked to the fan blade geometry.

  14. Mechanical Behaviour of Conventional Materials at Experimental Conditions of Deep Drawing Technological Process

    NASA Astrophysics Data System (ADS)

    Nikolov, N.; Pashkouleva, D.; Kavardzhikov, V.

    2012-09-01

    The paper deals with experimental investigations on the mechanical behaviour of body-centred-cubic (BCC) and face-centred-cubic (FCC)-conventionally structured sheet metalic-metalic materials under stress-strain conditions of a deep drawing process determined by a coefficient close to the limiting one for Steel 08 and punch diameter of 50 mm. The mechanical characteristics of the investigated materials are identified by one-dimensional tension tests. The materials' responses, as results of identical loading conditions, are described by the change of blank sizes and characteristics of the forming processes. The chosen deformation path ensures obtaining a qualitative steel piece and leads to failures of aluminium and brass blanks. The reported results could be useful for investigations and predictions of the mechanical responses of such type metallic structures applying microscopic instrumented observations and numerical simulations.

  15. Influence of Experimental Conditions on Electronic Tongue Results—Case of Valsartan Minitablets Dissolution

    PubMed Central

    Wesoły, Małgorzata; Kluk, Anna; Sznitowska, Małgorzata; Ciosek, Patrycja; Wróblewski, Wojciech

    2016-01-01

    A potentiometric electronic tongue was applied to study the release of valsartan from pharmaceutical formulations, i.e., minitablets uncoated and coated with Eudragit E. Special attention was paid to evaluate the influence of medium temperature and composition, as well as to compare the performances of the sensor arrays working in various hydrodynamic conditions. The drug dissolution profiles registered with the ion-sensitive electrodes were compared with standard dissolution tests performed with USP Apparatus 2 (paddle). Moreover, the signal changes of all sensors were processed by principal component analysis to visualize the release modifications, related to the presence of the coating agent. Finally, the importance and influence of the experimental conditions on the results obtained using potentiometric sensor arrays were discussed. PMID:27563904

  16. Experimental investigation on statistical properties of wave heights and crests in crossing sea conditions

    NASA Astrophysics Data System (ADS)

    Sabatino, Alessandro D.; Serio, Marina

    2015-05-01

    Some theoretical and numerical studies highlighted that the occurrence of rogue waves could increase in the presence of crossing sea. This sea state is characterized by the coexistence of two wave systems with different directions of propagations and is considered one of the most common causes of ship accidents in bad weather conditions. In particular, the angle between the two interacting wavetrains, Δθ, was found to be an important parameter that could lead to an enhanced probability of extreme events. We present an experimental investigation on wave heights and crest for surface elevation mechanically generated in different crossing sea conditions (10° < Δθ < 40°). The results of statistical analysis confirm that the probability of extreme events increases with the angle between the two systems, but does not exceed the values of the unidirectional case, which also presents waves with greater heights. Moreover, the correlation between the heights, crests, and troughs of consecutive waves assumes higher values for the case of 40°, when compared to the unidirectional case: this could mean that it is easier to find waves of the same height within a packet in the conditions Δθ = 40° with respect to the unidirectional or other Δθ conditions considered.

  17. Simulation of VSPT Experimental Cascade Under High and Low Free-Stream Turbulence Conditions

    NASA Technical Reports Server (NTRS)

    Ameri, Ali A.; Giel, Paul W.; Flegel, Ashlie B.

    2014-01-01

    Variable-Speed Power Turbines (VSPT) for rotorcraft applications operate at low Reynolds number and over a wide range in incidence associated with shaft speed change. A comprehensive linear cascade data set obtained includes the effects of Reynolds number, free-stream turbulence and incidence is available and this paper concerns itself with the presentation and numerical simulation of conditions resulting in a selected set of those data. As such, post-dictions of blade pressure loading, total-pressure loss and exit flow angles under conditions of high and low turbulence intensity for a single Reynolds number are presented. Analyses are performed with the three-equation turbulence models of Walters-Leylek and Walters and Cokljat. Transition, loading, total-pressure loss and exit angle variations are presented and comparisons are made with experimental data as available. It is concluded that at the low freestream turbulence conditions the Walters-Cokljat model is better suited to predictions while for high freestream conditions the two models generate similar predications that are generally satisfactory.

  18. Simulation of VSPT Experimental Cascade Under High and Low Free-Stream Turbulence Conditions

    NASA Technical Reports Server (NTRS)

    Ameri, Ali A.; Giel, Paul W.; Flegel, Ashlie B.

    2015-01-01

    Variable-Speed Power Turbines (VSPT) for rotorcraft applications operate at low Reynolds number and over a wide range in incidence associated with shaft speed change. A comprehensive linear cascade data set obtained includes the effects of Reynolds number, free-stream turbulence and incidence is available and this paper concerns itself with the presentation and numerical simulation of conditions resulting in a selected set of those data. As such, post-dictions of blade pressure loading, total-pressure loss and exit flow angles under conditions of high and low turbulence intensity for a single Reynolds number are presented. Analyses are performed with the three-equation turbulence models of Walters- Leylek and Walters and Cokljat. Transition, loading, total-pressure loss and exit angle variations are presented and comparisons are made with experimental data as available. It is concluded that at the low freestream turbulence conditions the Walters-Cokljat model is better suited to predictions while for high freestream conditions the two models generate similar predications that are generally satisfactory.

  19. Experimental evaluation of automotive air-conditioning using HFC-134a and HC-134a

    NASA Astrophysics Data System (ADS)

    Nasution, Henry; Zainudin, Muhammad Amir; Aziz, Azhar Abdul; Latiff, Zulkarnain Abdul; Perang, Mohd Rozi Mohd; Rahman, Abd Halim Abdul

    2012-06-01

    An experimental study to evaluate the energy consumption of an automotive air conditioning is presented. In this study, these refrigerants will be tested using the experimental rig which simulated the actual cars as a cabin complete with a cooling system component of the actual car that is as the blower, evaporator, condenser, radiators, electric motor, which acts as a vehicle engine, and then the electric motor will operate the compressor using a belt and pulley system, as well as to the alternator will recharge the battery. The compressor working with the fluids HFC-134a and HC-134a and has been tested varying the speed in the range 1000, 1500, 2000 and 2500 rpm. The measurements taken during the one hour experimental periods at 2-minutes interval times for temperature setpoint of 20°C with internal heat loads 0, 500, 700 and 1000 W. The final results of this study show an overall better energy consumption of the HFC-134a compared with the HC-134a.

  20. Experimental evidence for the conditions necessary to sustain meandering in coarse-bedded rivers.

    PubMed

    Braudrick, Christian A; Dietrich, William E; Leverich, Glen T; Sklar, Leonard S

    2009-10-06

    Meandering rivers are common on Earth and other planetary surfaces, yet the conditions necessary to maintain meandering channels are unclear. As a consequence, self-maintaining meandering channels with cutoffs have not been reproduced in the laboratory. Such experimental channels are needed to explore mechanisms controlling migration rate, sinuosity, floodplain formation, and planform morphodynamics and to test theories for wavelength and bend propagation. Here we report an experiment in which meandering with near-constant width was maintained during repeated cutoff and regeneration of meander bends. We found that elevated bank strength (provided by alfalfa sprouts) relative to the cohesionless bed material and the blocking of troughs (chutes) in the lee of point bars via suspended sediment deposition were the necessary ingredients to successful meandering. Varying flood discharge was not necessary. Scaling analysis shows that the experimental meander migration was fast compared to most natural channels. This high migration rate caused nearly all of the bedload sediment to exchange laterally, such that bar growth was primarily dependent on bank sediment supplied from upstream lateral migration. The high migration rate may have contributed to the relatively low sinuosity of 1.19, and this suggests that to obtain much higher sinuosity experiments at this scale may have to be conducted for several years. Although patience is required to evolve them, these experimental channels offer the opportunity to explore several fundamental issues about river morphodynamics. Our results also suggest that sand supply may be an essential control in restoring self-maintaining, actively shifting gravel-bedded meanders.

  1. EXPERIMENTAL AND THEORETICAL DETERMINATION OF HEAVY OIL VISCOSITY UNDER RESERVOIR CONDITIONS

    SciTech Connect

    Dr. Jorge Gabitto; Maria Barrufet

    2003-05-01

    The USA deposits of heavy oils and tar sands contain significant energy reserves. Thermal methods, particularly steam drive and steam soak, are used to recover heavy oils and bitumen. Thermal methods rely on several displacement mechanisms to recover oil, but the most important is the reduction of crude viscosity with increasing temperature. The main objective of this research is to propose a simple procedure to predict heavy oil viscosity at reservoir conditions as a function of easily determined physical properties. This procedure will avoid costly experimental testing and reduce uncertainty in designing thermal recovery processes. First, we reviewed critically the existing literature choosing the most promising models for viscosity determination. Then, we modified an existing viscosity correlation, based on the corresponding states principle in order to fit more than two thousand commercial viscosity data. We collected data for compositional and black oil samples (absence of compositional data). The data were screened for inconsistencies resulting from experimental error. A procedure based on the monotonic increase or decrease of key variables was implemented to carry out the screening process. The modified equation was used to calculate the viscosity of several oil samples where compositional data were available. Finally, a simple procedure was proposed to calculate black oil viscosity from common experimental information such as, boiling point, API gravity and molecular weight.

  2. An experimental study of incongruent dissolution of CaCO3 under analogue glacial conditions

    NASA Astrophysics Data System (ADS)

    McGillen, Max R.; Fairchild, Ian J.

    This paper addresses the nature of incongruent dissolution of calcite in glacial settings using an experimental approach. Various CaCO3 samples were comminuted using two contrasting techniques (dry machine-milling, and hand-grinding of an ice water mixture) and dissolved to calcite saturation in both high-pCO2 (10-2 atm) and low-pCO2 (10-3.5 = atmospheric) conditions. Ion yields of Ca, Mg and Sr were determined at the end of the experiments. Leachates displayed enhancement of Mg/Ca and Sr/Ca by a factor of 1.3 8.3 compared with bulk solid carbonate. Lower Mg/Ca and Sr/Ca ratios under higher-pCO2 conditions reflect the percentage dissolution of the carbonate, not the pCO2 per se. The experimental results imply that reported natural incongruent dissolution is readily reproducible in the laboratory and is primarily dependent on the water/rock ratio. Quantitative analysis of new and previous results suggests that the effect relates to the most reactive 0.15 0.25% of the sample, equating volumetrically to the outer few lattice layers, and it is interpreted as an anomalous leaching behaviour of calcite surfaces freshly exposed by crushing. This phenomenon could serve as an index of the relative efficiencies of fragmenting and dissolutional processes in glacial environments.

  3. Development of an Experimental Setup for the Measurement of the Coefficient of Restitution under Vacuum Conditions.

    PubMed

    Drücker, Sven; Krautstrunk, Isabell; Paulick, Maria; Saleh, Khashayar; Morgeneyer, Martin; Kwade, Arno

    2016-03-29

    The Discrete Element Method is used for the simulation of particulate systems to describe and analyze them, to predict and afterwards optimize their behavior for single stages of a process or even an entire process. For the simulation with occurring particle-particle and particle-wall contacts, the value of the coefficient of restitution is required. It can be determined experimentally. The coefficient of restitution depends on several parameters like the impact velocity. Especially for fine particles the impact velocity depends on the air pressure and under atmospheric pressure high impact velocities cannot be reached. For this, a new experimental setup for free-fall tests under vacuum conditions is developed. The coefficient of restitution is determined with the impact and rebound velocity which are detected by a high-speed camera. To not hinder the view, the vacuum chamber is made of glass. Also a new release mechanism to drop one single particle under vacuum conditions is constructed. Due to that, all properties of the particle can be characterized beforehand.

  4. Experimental study of temporal evolution of waves under transient wind conditions

    NASA Astrophysics Data System (ADS)

    Zavadsky, Andrey; Shemer, Lev

    2016-11-01

    Temporal variation of the waves excited by nearly sudden wind forcing over an initially still water surface is studied in a small wind-wave flume at Tel Aviv University for variety of fetches and wind velocities. Simultaneous measurements of the surface elevation using a conventional capacitance wave-gauge and of the surface slope in along-wind and cross-wind directions by a laser slope gauge were performed. Variation with time of two components of instantaneous surface velocity was measured by particle tracking velocimetry. The size of the experimental facility and thus relatively short characteristic time scales of the phenomena under investigation, as well as an automated experimental procedure controlling the experiments made it possible to record a large amount of independent realizations for each wind-fetch condition. Sufficient data were accumulated to compute reliable ensemble averaged temporal variation of governing wave parameters. The essentially three-dimensional structure of wind-waves at all stages of evolution is demonstrated. The results obtained at each wind-fetch condition allowed to characterize the major stages of the evolution of the wind-wave field and to suggest a plausible scenario for the initial growth of the wind-waves.

  5. Experimental verification of boundary conditions for numerical simulation of airflow in a benchmark ventilation channel

    NASA Astrophysics Data System (ADS)

    Lizal, Frantisek; Niedoba, Pavel; Seda, Libor; Jedelsky, Jan; Jicha, Miroslav

    2016-03-01

    Correct definition of boundary conditions is crucial for the appropriate simulation of a flow. It is a common practice that simulation of sufficiently long upstream entrance section is performed instead of experimental investigation of the actual conditions at the boundary of the examined area, in the case that the measurement is either impossible or extremely demanding. We focused on the case of a benchmark channel with ventilation outlet, which models a regular automotive ventilation system. At first, measurements of air velocity and turbulence intensity were performed at the boundary of the examined area, i.e. in the rectangular channel 272.5 mm upstream the ventilation outlet. Then, the experimentally acquired results were compared with results obtained by numerical simulation of further upstream entrance section defined according to generally approved theoretical suggestions. The comparison showed that despite the simple geometry and general agreement of average axial velocity, certain difference was found in the shape of the velocity profile. The difference was attributed to the simplifications of the numerical model and the isotropic turbulence assumption of the used turbulence model. The appropriate recommendations were stated for the future work.

  6. Concept of relative variability of cardiac action potential duration and its test under various experimental conditions.

    PubMed

    Magyar, János; Kistamás, Kornél; Váczi, Krisztina; Hegyi, Bence; Horváth, Balázs; Bányász, Tamás; Nánási, Péter P; Szentandrássy, Norbert

    2016-01-01

    Beat-to-beat variability of action potential duration (short-term variability, SV) is an intrinsic property of mammalian myocardium. Since the majority of agents and interventions affecting SV may modify also action potential duration (APD), we propose here the concept of relative SV (RSV), where changes in SV are normalized to changes in APD and these data are compared to the control SV-APD relationship obtained by lengthening or shortening of action potentials by inward and outward current injections. Based on this concept the influence of the several experimental conditions like stimulation frequency, temperature, pH, redox-state and osmolarity were examined on RSV in canine ventricular myocytes using sharp microelectrodes. RSV was increased by high stimulation frequency (cycle lengths <0.7 s), high temperature (above 37ºC), oxidative agents (H2O2), while it was decreased by reductive environment. RSV was not affected by changes in pH (within the range of 6.4-8.4) and osmolarity of the solution (between 250-350 mOsm). The results indicate that changes in beat-to-beat variability of APD must be evaluated exclusively in terms of RSV; furthermore, some experimental conditions, including the stimulation frequency, redox-state and temperature have to be controlled strictly when analyzing alterations in the short-term variability of APD.

  7. Experimental investigation of transient thermal behavior of an airship under different solar radiation and airflow conditions

    NASA Astrophysics Data System (ADS)

    Li, De-Fu; Xia, Xin-Lin; Sun, Chuang

    2014-03-01

    Knowledge of the thermal behavior of airships is crucial to the development of airship technology. An experiment apparatus is constructed to investigate the thermal response characteristics of airships, and the transient temperature distributions of both hull and inner gas are obtained under the irradiation of a solar simulator and various airflow conditions. In the course of the research, the transient temperature change of the experimental airship is measured for four airflow speeds of 0 m/s (natural convection), 3.26 m/s, 5.5 m/s and 7.0 m/s, and two incident solar radiation values of 842.4 W/m2 and 972.0 W/m2. The results show that solar irradiation has significant influence on the airship hull and inner gas temperatures even if the airship stays in a ground airflow environment where the heat transfer is dominated by radiation and convection. The airflow around the airship is conducive to reduce the hull temperature and temperature nonuniformity. Transient thermal response of airships rapidly varies with time under solar radiation conditions and the hull temperature remains approximately constant in ˜5-10 min. Finally, a transient thermal model of airship is developed and the model is validated through comparison with the experimental data.

  8. Computational ecotoxicology: simultaneous prediction of ecotoxic effects of nanoparticles under different experimental conditions.

    PubMed

    Kleandrova, Valeria V; Luan, Feng; González-Díaz, Humberto; Ruso, Juan M; Melo, André; Speck-Planche, Alejandro; Cordeiro, M Natália D S

    2014-12-01

    Nanotechnology has brought great advances to many fields of modern science. A manifold of applications of nanoparticles have been found due to their interesting optical, electrical, and biological/chemical properties. However, the potential toxic effects of nanoparticles to different ecosystems are of special concern nowadays. Despite the efforts of the scientific community, the mechanisms of toxicity of nanoparticles are still poorly understood. Quantitative-structure activity/toxicity relationships (QSAR/QSTR) models have just started being useful computational tools for the assessment of toxic effects of nanomaterials. But most QSAR/QSTR models have been applied so far to predict ecotoxicity against only one organism/bio-indicator such as Daphnia magna. This prevents having a deeper knowledge about the real ecotoxic effects of nanoparticles, and consequently, there is no possibility to establish an efficient risk assessment of nanomaterials in the environment. In this work, a perturbation model for nano-QSAR problems is introduced with the aim of simultaneously predicting the ecotoxicity of different nanoparticles against several assay organisms (bio-indicators), by considering also multiple measures of ecotoxicity, as well as the chemical compositions, sizes, conditions under which the sizes were measured, shapes, and the time during which the diverse assay organisms were exposed to nanoparticles. The QSAR-perturbation model was derived from a database containing 5520 cases (nanoparticle-nanoparticle pairs), and it was shown to exhibit accuracies of ca. 99% in both training and prediction sets. In order to demonstrate the practical applicability of our model, three different nickel-based nanoparticles (Ni) with experimental values reported in the literature were predicted. The predictions were found to be in very good agreement with the experimental evidences, confirming that Ni-nanoparticles are not ecotoxic when compared with other nanoparticles. The results

  9. Establishment and performance of an experimental green roof under extreme climatic conditions.

    PubMed

    Klein, Petra M; Coffman, Reid

    2015-04-15

    Green roofs alter the surface energy balance and can help in mitigating urban heat islands. However, the cooling of green roofs due to evapotranspiration strongly depends on the climatic conditions, and vegetation type and density. In the Southern Central Plains of the United States, extreme weather events, such as high winds, heat waves and drought conditions pose challenges for successful implementation of green roofs, and likely alter their standard performance. The National Weather Center Experimental Green Roof, an interdisciplinary research site established in 2010 in Norman, OK, aimed to investigate the ecological performance and surface energy balance of green roof systems. Starting in May 2010, 26 months of vegetation studies were conducted and the radiation balance, air temperature, relative humidity, and buoyancy fluxes were monitored at two meteorological stations during April-October 2011. The establishment of a vegetative community trended towards prairie plant dominance. High mortality of succulents and low germination of grasses and herbaceous plants contributed to low vegetative coverage. In this condition succulent diversity declined. Bouteloua gracilis and Delosperma cooperi showed typological dominance in harsh climatic conditions, while Sedum species experienced high mortality. The plant community diversified through volunteers such as Euphorbia maculate and Portulaca maculate. Net radiation measured at a green-roof meteorological station was higher than at a control station over the original, light-colored roofing material. These findings indicate that the albedo of the green roof was lower than the albedo of the original roofing material. The low vegetative coverage during the heat and drought conditions in 2011, which resulted in the dark substrate used in the green roof containers being exposed, likely contributed to the low albedo values. Nevertheless, air temperatures and buoyancy fluxes were often lower over the green roof indicating

  10. Serum thyroglobulin reference intervals in regions with adequate and more than adequate iodine intake.

    PubMed

    Wang, Zhaojun; Zhang, Hanyi; Zhang, Xiaowen; Sun, Jie; Han, Cheng; Li, Chenyan; Li, Yongze; Teng, Xiaochun; Fan, Chenling; Liu, Aihua; Shan, Zhongyan; Liu, Chao; Weng, Jianping; Teng, Weiping

    2016-11-01

    The purpose of this study was to establish normal thyroglobulin (Tg) reference intervals (RIs) in regions with adequate and more than adequate iodine intake according to the National Academy of Clinical Biochemistry (NACB) guidelines and to investigate the relationships between Tg and other factors.A total of 1317 thyroid disease-free adult subjects (578 men, 739 nonpregnant women) from 2 cities (Guangzhou and Nanjing) were enrolled in this retrospective, observational study. Each subject completed a questionnaire and underwent physical and ultrasonic examination. Serum Tg, thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), Tg antibody (TgAb), and urinary iodine concentration (UIC) were measured. Reference groups were established on the basis of TSH levels: 0.5 to 2.0 and 0.27 to 4.2 mIU/L.The Tg RIs for Guangzhou and Nanjing were 1.6 to 30.0 and 1.9 to 25.8 ng/mL, respectively. No significant differences in Tg were found between genders or among different reference groups. Stepwise linear regression analyses showed that TgAb, thyroid volume, goiter, gender, age, and TSH levels were correlated with Tg.In adults from regions with adequate and more than adequate iodine intake, we found that Tg may be a suitable marker of iodine status; gender-specific Tg RI was unnecessary; there was no difference between Tg RIs in regions with adequate and more than adequate iodine intake; and the TSH criterion for selecting the Tg reference population could follow the local TSH reference rather than 0.5 to 2.0 mIU/L.

  11. Serum thyroglobulin reference intervals in regions with adequate and more than adequate iodine intake

    PubMed Central

    Wang, Zhaojun; Zhang, Hanyi; Zhang, Xiaowen; Sun, Jie; Han, Cheng; Li, Chenyan; Li, Yongze; Teng, Xiaochun; Fan, Chenling; Liu, Aihua; Shan, Zhongyan; Liu, Chao; Weng, Jianping; Teng, Weiping

    2016-01-01

    Abstract The purpose of this study was to establish normal thyroglobulin (Tg) reference intervals (RIs) in regions with adequate and more than adequate iodine intake according to the National Academy of Clinical Biochemistry (NACB) guidelines and to investigate the relationships between Tg and other factors. A total of 1317 thyroid disease-free adult subjects (578 men, 739 nonpregnant women) from 2 cities (Guangzhou and Nanjing) were enrolled in this retrospective, observational study. Each subject completed a questionnaire and underwent physical and ultrasonic examination. Serum Tg, thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), Tg antibody (TgAb), and urinary iodine concentration (UIC) were measured. Reference groups were established on the basis of TSH levels: 0.5 to 2.0 and 0.27 to 4.2 mIU/L. The Tg RIs for Guangzhou and Nanjing were 1.6 to 30.0 and 1.9 to 25.8 ng/mL, respectively. No significant differences in Tg were found between genders or among different reference groups. Stepwise linear regression analyses showed that TgAb, thyroid volume, goiter, gender, age, and TSH levels were correlated with Tg. In adults from regions with adequate and more than adequate iodine intake, we found that Tg may be a suitable marker of iodine status; gender-specific Tg RI was unnecessary; there was no difference between Tg RIs in regions with adequate and more than adequate iodine intake; and the TSH criterion for selecting the Tg reference population could follow the local TSH reference rather than 0.5 to 2.0 mIU/L. PMID:27902589

  12. A thermodynamic and experimental study of the conditions of thaumasite formation

    SciTech Connect

    Schmidt, Thomas Lothenbach, Barbara; Romer, Michael; Scrivener, Karen; Rentsch, Daniel; Figi, Renato

    2008-03-15

    The formation of thaumasite was investigated with the progressive equilibrium approach (PEA). This approach experimentally simulates the conditions of various levels of sulfate addition in hardened cement pastes. The influence of limestone, time, C{sub 3}A content, temperature and leaching on thaumasite formation was investigated. The results show that thaumasite formation is favoured at lower temperatures (8 deg. C) independently of the type of cement clinker (high or low C{sub 3}A content) used. Thaumasite was found to form only in systems where limestone was present and where sufficient sulfate had been added. Thaumasite precipitated only in systems where the Al present has already been consumed to form ettringite and the molar SO{sub 3}/Al{sub 2}O{sub 3} ratio exceeded 3. In leached samples (reduction of portlandite and alkalis) slightly less thaumasite was formed whereas gypsum and ettringite are favoured under these conditions. The PEA, used to investigate the chemical aspects of sulfate attack was found to be a good tool for simulating external sulfate attack. Generally, thaumasite was detected were it was modelled to be stable in significant amounts. However, in this study equilibrium conditions were not reached after 9 months.

  13. Simulations of the Richtmyer-Meshkov Instability with experimentally measured volumetric initial conditions

    NASA Astrophysics Data System (ADS)

    Ferguson, Kevin; Sewell, Everest; Krivets, Vitaliy; Greenough, Jeffrey; Jacobs, Jeffrey

    2016-11-01

    Initial conditions for the Richtmyer-Meshkov instability (RMI) are measured in three dimensions in the University of Arizona Vertical Shock Tube using a moving magnet galvanometer system. The resulting volumetric data is used as initial conditions for the simulation of the RMI using ARES at Lawrence-Livermore National Laboratory (LLNL). The heavy gas is sulfur hexafluoride (SF6), and the light gas is air. The perturbations are generated by harmonically oscillating the gasses vertically using two loudspeakers mounted to the shock tube which cause Faraday resonance, producing a random short wavelength perturbation on the interface. Planar Mie scattering is used to illuminate the flow field through the addition of propylene glycol particles seeded in the heavy gas. An M=1.2 shock impulsively accelerates the interface, initiating instability growth. Images of the initial condition and instability growth are captured at a rate of 6 kHz using high speed cameras. Comparisons between experimental and simulation results, mixing diagnostics, and mixing zone growth are presented.

  14. Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

    SciTech Connect

    Muthukumaran, C. K.; Vaidyanathan, Aravind

    2015-03-15

    The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed.

  15. Comparison of Pavlovian serial conditional discrimination in rats and hamsters in the same experimental situation.

    PubMed

    Bueno, J L; Figueiredo, T H; Mello, F M

    2001-12-01

    The present study compares behavioral changes between two distinct rodent groups, hamsters (Mesocricetus auratus) and Wistar rats, when submitted in the same homogeneous experimental situations to a serial conditional discrimination procedure which involves water deprivation and the processing of temporal variables. Both hamsters and rats acquired serial positive conditional discrimination as indicated by higher frequencies of magazine-oriented behavior during the tone followed by reinforcement (T+) and preceded by the feature stimulus light (L) and during the empty interval, than during the tone alone not followed by reinforcement (T-). Rats' frequencies of magazine-oriented behavior were high during T+ and T-, initially during training, and decreased during T- as the training progressed. However, the hamsters' frequencies of magazine-oriented behavior started very low and increased only during T+ as the training progressed. Comparison of the frequencies of magazine-oriented behavior during the empty interval in relation to the frequencies during the preceding L period showed that rats' frequencies remained very high and hamsters' frequencies increased during training. These results suggest that rats and hamsters have different behavioral strategies for the acquisition of a conditional discrimination. The results of the comparisons made in these experiments support the view of the importance of an ecological psychology approach to the understanding of complex learning in animals.

  16. Experimental Validation of Modeled Fe Opacities at Conditions Approaching the Base of the Solar Convection Zone

    NASA Astrophysics Data System (ADS)

    Nagayama, Taisuke

    2013-10-01

    Knowledge of the Sun is a foundation for other stars. However, after the solar abundance revision in 2005, standard solar models disagree with helioseismic measurements particularly at the solar convection zone base (CZB, r ~ 0 . 7 ×RSun) [Basu, et al., Physics Reports 457, 217 (2008)]. One possible explanation is an underestimate in the Fe opacity at the CZB [Bailey et al., Phys. Plasmas 16, 058101 (2009)]. Modeled opacities are important physics inputs for plasma simulations (e.g. standard solar models). However, modeled opacities are not experimentally validated at high temperatures because of three challenging criteria required for reliable opacity measurements: 1) smooth and strong backlighter, 2) plasma condition uniformity, and 3) simultaneous measurements of plasma condition and transmission. Fe opacity experiments are performed at the Sandia National Laboratories (SNL) Z-machine aiming at conditions close to those at the CZB (i.e. Te = 190 eV, ne = 1 ×1023 cm-3). To verify the quality of the experiments, it is critical to investigate how well the three requirements are satisfied. The smooth and strong backlighter is provided by the SNL Z-pinch dynamic hohlraum. Fe plasma condition is measured by mixing Mg into the Fe sample and employing Mg K-shell line transmission spectroscopy. Also, an experiment is designed and performed to measure the level of non-uniformity in the Fe plasma by mixing Al and Mg dopants on the opposite side of the Fe sample and analyzing their spectra. We will present quantitative results on these investigations as well as the comparison of the measured opacity to modeled opacities. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

  17. Experimental Investigation of Pressure-volume-Temperature Mass Gauging Method Under Microgravity Condition by Parabolic Flight

    NASA Astrophysics Data System (ADS)

    Seo, Mansu; Park, Hana; Yoo, DonGyu; Jung, Youngsuk; Jeong, Sangkwon

    Gauging the volume or mass of liquid propellant of a rocket vehicle in space is an important issue for its economic feasibility and optimized design of loading mass. Pressure-volume-temperature (PVT) gauging method is one of the most suitable measuring techniques in space due to its simplicity and reliability. This paper presents unique experimental results and analyses of PVT gauging method using liquid nitrogen under microgravity condition by parabolic flight. A vacuum-insulated and cylindrical-shaped liquid nitrogen storage tank with 9.2 L volume is manufactured by observing regulation of parabolic flight. PVT gauging experiments are conducted under low liquid fraction condition from 26% to 32%. Pressure, temperature, and the injected helium mass into the storage tank are measured to obtain the ullage volume by gas state equation. Liquid volume is finally derived by the measured ullage volume and the known total tank volume. Two sets of parabolic flights are conducted and each set is composed of approximately 10 parabolic flights. In the first set of flights, the short initial waiting time (3 ∼ 5 seconds) cannot achieve sufficient thermal equilibrium condition at the beginning. It causes inaccurate gauging results due to insufficient information of the initial helium partial pressure in the tank. The helium injection after 12 second waiting time at microgravity condition with high mass flow rate in the second set of flights achieves successful initial thermal equilibrium states and accurate measurement results of initial helium partial pressure. Liquid volume measurement errors in the second set are within 11%.

  18. Deformation mechanisms of antigorite serpentinite at subduction zone conditions determined from experimentally and naturally deformed rocks

    NASA Astrophysics Data System (ADS)

    Auzende, Anne-Line; Escartin, Javier; Walte, Nicolas P.; Guillot, Stéphane; Hirth, Greg; Frost, Daniel J.

    2015-02-01

    We performed deformation-DIA experiments on antigorite serpentinite at pressures of 1-3.5 GPa and temperatures of between 400 and 650 °C, bracketing the stability of antigorite under subduction zone conditions. For each set of pressure-temperature (P-T) conditions, we conducted two runs at strain rates of 5 ×10-5 and 1 ×10-4 s-1. We complemented our study with a sample deformed in a Griggs-type apparatus at 1 GPa and 400 °C (Chernak and Hirth, 2010), and with natural samples from Cuba and the Alps deformed under blueschist/eclogitic conditions. Optical and transmission electron microscopies were used for microstructural characterization and determination of deformation mechanisms. Our observations on experimentally deformed antigorite prior to breakdown show that deformation is dominated by cataclastic flow with observable but minor contribution of plastic deformation (microkinking and (001) gliding mainly expressed by stacking disorder mainly). In contrast, in naturally deformed samples, plastic deformation structures are dominant (stacking disorder, kinking, pressure solution), with minor but also perceptible contribution of brittle deformation. When dehydration occurs in experiments, plasticity increases and is coupled to local embrittlement that we attribute to antigorite dehydration. In dehydrating samples collected in the Alps, embrittlement is also observed suggesting that dehydration may contribute to intermediate-depth seismicity. Our results thus show that semibrittle deformation operates within and above the stability field of antigorite. However, the plastic deformation recorded by naturally deformed samples was likely acquired at low strain rates. We also document that the corrugated structure of antigorite controls the strain accommodation mechanisms under subduction conditions, with preferred inter- and intra-grain cracking along (001) and gliding along both a and b. We also show that antigorite rheology in subduction zones is partly controlled

  19. Experimental Observations of Localization Phenomena in Sands: Plane Strain Versus Triaxial Compression Conditions

    NASA Technical Reports Server (NTRS)

    Alshibli, Khalid A.; Batiste, Susan N.; Sture, Stein; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    A comprehensive experimental investigation was conducted to investigate the effects of loading condition and confining pressure on strength properties and instability phenomena in sands. A uniform sub-rounded to rounded natural silica sand known as F-75 Ottawa sand was used in the investigation. The results of a series on Conventional Triaxial Compression (CTC) experiments tested under very low confining pressures (0.05 - 1.30) kPa tested in a Microgravity environment abroad the NASA Space Shuttle are presented in addition to the results similar specimens tested in terrestrial laboratory to investigate the effect of confining pressure on the constitutive behavior of sands. The behavior of the CTC experiments is compared with the results of Plane Strain (PS) experiments. Computed tomography and other digital imaging techniques were used to study the development and evolution of shear bands.

  20. Non-verbal mother-child communication in conditions of maternal HIV in an experimental environment.

    PubMed

    de Sousa Paiva, Simone; Galvão, Marli Teresinha Gimeniz; Pagliuca, Lorita Marlena Freitag; de Almeida, Paulo César

    2010-01-01

    Non-verbal communication is predominant in the mother-child relation. This study aimed to analyze non-verbal mother-child communication in conditions of maternal HIV. In an experimental environment, five HIV-positive mothers were evaluated during care delivery to their babies of up to six months old. Recordings of the care were analyzed by experts, observing aspects of non-verbal communication, such as: paralanguage, kinesics, distance, visual contact, tone of voice, maternal and infant tactile behavior. In total, 344 scenes were obtained. After statistical analysis, these permitted inferring that mothers use non-verbal communication to demonstrate their close attachment to their children and to perceive possible abnormalities. It is suggested that the mothers infection can be a determining factor for the formation of mothers strong attachment to their children after birth.

  1. Experimental study on ignition characteristics of pulverized coal under high-temperature oxygen condition

    NASA Astrophysics Data System (ADS)

    Liu, G. W.; Liu, Y. H.; Dong, P.

    2016-08-01

    The high-temperature oxygen ignition technology of pulverized coal, which can replace the oil gun and achieve oil-free pulverized coal ignition by mixing the high- temperature oxygen and the pulverized coal stream directly, was proposed and a relevant ignition experimental system was built. The ignition characteristics of pulverized coal under high-temperature oxygen condition were investigated: the ignition process was described and analyzed, the influence of relevant parameters on the pulverized coal stream ignition were obtained and analyzed. The results showed: when the oxygen heating temperature is over 750 °C, the pulverized coal stream could be ignited successfully by high-temperature oxygen; increasing the pulverized coal concentration, primary air temperature and oxygen volume flow rate or decreasing the primary air velocity is helpful for the ignition and combustion of the pulverized coal stream.

  2. Universal limiting shape of worn profile under multiple-mode fretting conditions: theory and experimental evidence

    NASA Astrophysics Data System (ADS)

    Dmitriev, Andrey I.; Voll, Lars B.; Psakhie, Sergey G.; Popov, Valentin L.

    2016-03-01

    We consider multiple-mode fretting wear in a frictional contact of elastic bodies subjected to a small-amplitude oscillation, which may include in-plane and out-of-plane translation, torsion and tilting (“periodic rolling”). While the detailed kinetics of wear depends on the particular loading history and wear mechanism, the final worn shape, under some additional conditions, occurs to be universal for all types and loading and wear mechanisms. This universal form is determined solely by the radius of the permanent stick region and the maximum indentation depth during the loading cycle. We provide experimental evidence for the correctness of the theoretically predicted limiting shape. The existence of the universal limiting shape can be used for designing joints which are resistant to fretting wear.

  3. Universal limiting shape of worn profile under multiple-mode fretting conditions: theory and experimental evidence

    PubMed Central

    Dmitriev, Andrey I.; Voll, Lars B.; Psakhie, Sergey G.; Popov, Valentin L.

    2016-01-01

    We consider multiple-mode fretting wear in a frictional contact of elastic bodies subjected to a small-amplitude oscillation, which may include in-plane and out-of-plane translation, torsion and tilting (“periodic rolling”). While the detailed kinetics of wear depends on the particular loading history and wear mechanism, the final worn shape, under some additional conditions, occurs to be universal for all types and loading and wear mechanisms. This universal form is determined solely by the radius of the permanent stick region and the maximum indentation depth during the loading cycle. We provide experimental evidence for the correctness of the theoretically predicted limiting shape. The existence of the universal limiting shape can be used for designing joints which are resistant to fretting wear. PMID:26979092

  4. Relationship between nine haloacetic acids with total organic halogens in different experimental conditions.

    PubMed

    Pourmoghadas, Hossein; Kinman, Riley N

    2013-04-03

    The effects of pH and bromide ion concentration on the formation of nine haloacetic acids (HAAs) and total organic halogens (TOX) in chlorinated drinking water have been evaluated. In an extensive study, the relationships of nine HAAs with TOX have been investigated. Honesty Significant Differences test (HSD) and ANOVA tests were used for the statistical analyses. The study determined the concentration range of nine HAAs as of a percentage of TOX at varying experimental conditions. Statistical analyses showed that the parameters pH and Br had significant effects on the formation of nine HAAs and TOX. This study also showed that brominated and mixed species of HAAs would be dominant in the presence of high bromide ion concentration which contributes a high percentage of the TOX. The results of this study could be used to set up a maximum contaminant level of TOX as a water quality standard for chlorination by-products.

  5. Experimental Study and Modeling of the Photocatalytic Oxidation of No in Indoor Conditions

    NASA Astrophysics Data System (ADS)

    Yu, Q. L.; Brouwers, H. J. H.; Ballari, M. M.

    Heterogeneous photocatalytic oxidation (PCO) has shown to be a promising air purifying technology. Nitrogen monoxide (NO) is one common indoor air pollutant. The present paper addresses the PCO reaction in indoor conditions using NO as target pollutant with the gypsum plasterboard as a special substrate and carbon-doped TiO2 as photocatalyst. A photocatalytic reaction setup is introduced for the assessment of the indoor air quality. The PCO effect of the carbon-doped TiO2 is evaluated using different light wavelengths. Furthermore, the influence of the reactor volume on the PCO rate is studied. The Langmuir-Hinshelwood model is applied to describe the photocatalytic reaction mechanism. Experimental results show the validity of the L-H model in the present research. Using this model, a mathematical expression is proposed to describe the concentration change in the reactor.

  6. Experimental simulations of oxidizing conditions and organic decomposition on the surface of Mars

    NASA Technical Reports Server (NTRS)

    Stoker, C. R.; Mancinelli, Rocco L.; Mckay, Christopher P.

    1988-01-01

    One important scientific objective of a Mars Rover Sample Return mission would be to look for traces of living and extinct life on Mars. An instrument to search for organic carbon may be the simplest instrument that could screen samples which are interesting from a biological point of view. An experimental program is described which would help to understand the nature of the oxidizing soil on Mars and the mechanism responsible for organic degradation on the Martian surface. This is approached by lab simulations of the actual conditions that occur on Mars, particularly the oxidant production by atmospheric photochemistry, and the combined effects of UV light and oxidants in decomposing organic compounds. The results will be used to formulate models of the photochemistry of the atmospheric, the atmosphere-soil interaction, and the diffusion of reactive compounds into the soils. This information will provide insights and constraints on the design of a sampling strategy to search for organic compounds on Mars.

  7. Experimental study of horizontal annular channels under non-developed conditions

    SciTech Connect

    Delgadino, G.; Balino, J.; Carrica, P.

    1995-09-01

    In this work an experimental study of the two-phase air-water flow in a horizontal annular channel under non-developed conditions is presented. A conductive local probe was placed at the end of the channel to measure the local phase indication function under a wide range of gas and water flow rates. The signal was processed to obtain the void fraction and statistical distributions of liquid and gas residence times. From these data the topology of the flow could be inferred. A laser intermittence detector was also located close to the channel exit, in order to measure statistical parameters for intermittent flows by means of a two-probe method.

  8. Exergo-Economic Analysis of an Experimental Aircraft Turboprop Engine Under Low Torque Condition

    NASA Astrophysics Data System (ADS)

    Atilgan, Ramazan; Turan, Onder; Aydin, Hakan

    Exergo-economic analysis is an unique combination of exergy analysis and cost analysis conducted at the component level. In exergo-economic analysis, cost of each exergy stream is determined. Inlet and outlet exergy streams of the each component are associated to a monetary cost. This is essential to detect cost-ineffective processes and identify technical options which could improve the cost effectiveness of the overall energy system. In this study, exergo-economic analysis is applied to an aircraft turboprop engine. Analysis is based on experimental values at low torque condition (240 N m). Main components of investigated turboprop engine are the compressor, the combustor, the gas generator turbine, the free power turbine and the exhaust. Cost balance equations have been formed for all components individually and exergo-economic parameters including cost rates and unit exergy costs have been calculated for each component.

  9. A qualitative study of internal wave ship wakes: Dependence on environmental conditions and experimental parameters

    SciTech Connect

    Mullenhoff, C.J.; Brase, J.M.

    1995-04-24

    For the past several years the UK-US Radar Ocean Imaging Program has conducted a series of field experiments with the primary purpose of gathering real aperture radar (RAR) imagery at low grazing angle of ship-generated internal wave (IW) wakes. The first observations with RAR`s were made in the 1989 Loch Linnhe experiment where it was observed that radar images at low grazing angles (LGA) of approximately six degrees had significantly higher modulation levels than SAR images made at higher grazing angles of 35 - 65 degrees. These initial observations have led to several more experiments designed to verify the phenomenon and to test its dependence on experimental and environmental conditions. A parallel effort began to develop theoretical models of the LGA imaging process. Through this series of experiments we have developed an extensive database of radar imagery and supporting environmental data. The objective of this report is twofold: (1) To describe the database and the associated space of parameters. We will look at the coverage of the parameter space within the database and at areas which should be covered. (2) To take an initial look at the dependence of qualitative modulation strength on the experimental and environmental parameters. This first look will indicate the strongest dependencies which can then be studied in more detail. Section 2 describes the experimental database and Section 3 discusses the parameter space, image quality, and their relationships based on the images in the database. In Section 4 we summarize our conclusions and make recommendations for both future analyses and experiments.

  10. Experimental evidence for the conditions necessary to sustain meandering in coarse-bedded rivers

    PubMed Central

    Braudrick, Christian A.; Dietrich, William E.; Leverich, Glen T.; Sklar, Leonard S.

    2009-01-01

    Meandering rivers are common on Earth and other planetary surfaces, yet the conditions necessary to maintain meandering channels are unclear. As a consequence, self-maintaining meandering channels with cutoffs have not been reproduced in the laboratory. Such experimental channels are needed to explore mechanisms controlling migration rate, sinuosity, floodplain formation, and planform morphodynamics and to test theories for wavelength and bend propagation. Here we report an experiment in which meandering with near-constant width was maintained during repeated cutoff and regeneration of meander bends. We found that elevated bank strength (provided by alfalfa sprouts) relative to the cohesionless bed material and the blocking of troughs (chutes) in the lee of point bars via suspended sediment deposition were the necessary ingredients to successful meandering. Varying flood discharge was not necessary. Scaling analysis shows that the experimental meander migration was fast compared to most natural channels. This high migration rate caused nearly all of the bedload sediment to exchange laterally, such that bar growth was primarily dependent on bank sediment supplied from upstream lateral migration. The high migration rate may have contributed to the relatively low sinuosity of 1.19, and this suggests that to obtain much higher sinuosity experiments at this scale may have to be conducted for several years. Although patience is required to evolve them, these experimental channels offer the opportunity to explore several fundamental issues about river morphodynamics. Our results also suggest that sand supply may be an essential control in restoring self-maintaining, actively shifting gravel-bedded meanders. PMID:19805077

  11. COMPUTATIONAL MODELING AND EXPERIMENTAL STUDIES ON NOx REDUCTION UNDER PULVERIZED COAL COMBUSTION CONDITIONS

    SciTech Connect

    Subha K. Kumpaty; Kannikeswaran Subramanian; Victor P. Nokku; Tyrus L. Hodges; Adel Hassouneh; Ansumana Darboe; Sravan K. Kumpati

    1998-06-01

    In this work, both computer simulation and experimental studies were conducted to investigate several strategies for NO{sub x} reduction under pulverized coal combustion conditions with an aim to meet the stringent environmental standards for NO{sub x} control. Both computer predictions and reburning experiments yielded favorable results in terms of NO{sub x} control by reburning with a combination of methane and acetylene as well as non-selective catalytic reduction of NO{sub x} with ammonia following reburning with methane. The greatest reduction was achieved at the reburning stoichiometric ratio of 0.9; the reduction was very significant, as clearly shown in Chapters III and V. Both the experimental and computational results favored mixing gases: methane and acetylene (90% and 10% respectively) and methane and ammonia (98% and 2%) in order to get optimum reduction levels which can not be achieved by individual gases at any amounts. Also, the above gaseous compositions as reburning fuels seemed to have a larger window of stoichiometric ratio (SR2 < 0.9) as opposed to just methane (SR2=0.9) so as to reduce and keep NO{sub x} at low ppm levels. From the various computational runs, it has been observed that although there are several pathways that contribute to NO{sub x} reduction, the key pathway is NO {r_arrow} HCN {r_arrow} NH{sub 3} {r_arrow} N{sub 2} + H{sub 2}. With the trends established in this work, it is possible to scale the experimental results to real time industrial applications using computational calculations.

  12. 5-HT manipulation and dietary choice: variable carbohydrate (Polycose) suppression demonstrated only under specific experimental conditions.

    PubMed

    Lawton, C L; Blundell, J E

    1993-01-01

    The effects of six 5-HT anorectic agents, d-fenfluramine (5-HT releaser and reuptake inhibitor), fluoxetine (5-HT reuptake inhibitor), mCPP (5-HT1B/5-HT1C receptor agonist), RU24969 (5-HT1A/5-HT1B receptor agonist), MK212 (5-HT1C receptor agonist) and DOI (5-HT2/5-HT1C receptor agonist), and two non-5-HT anorectic agents, salbutamol (beta 2-adrenergic agonist) and d-amphetamine (catecholaminergic agonist), were examined in an experimental procedure designed to disclose selective effects on carbohydrate consumption. In this procedure, a revised version of what we have termed "The Classic Sclafani Paradigm", animals are presented with powdered Polycose as an optional carbohydrate supplement to hydrated chow (nutritionally complete diet). All drugs produced significant reductions in total (hydrated chow plus powdered Polycose) intake. However, only the 5-HT drugs DOI and fluoxetine exerted significantly stronger anorectic effects on intake of powdered Polycose than on intake of hydrated chow. d-Fenfluramine also showed a tendency to selectively suppress Polycose intake but this effect marginally failed to reach significance. These results suggest that when experimental conditions are favourable, what appears to be selective carbohydrate (Polycose) suppression can be demonstrated with certain 5-HT drugs. They also suggest that a selective effect on carbohydrate intake is not the most prominent feeding response to 5-HT drugs.

  13. Experimental conditions improving in-solution target enrichment for ancient DNA.

    PubMed

    Cruz-Dávalos, Diana I; Llamas, Bastien; Gaunitz, Charleen; Fages, Antoine; Gamba, Cristina; Soubrier, Julien; Librado, Pablo; Seguin-Orlando, Andaine; Pruvost, Mélanie; Alfarhan, Ahmed H; Alquraishi, Saleh A; Al-Rasheid, Khaled A S; Scheu, Amelie; Beneke, Norbert; Ludwig, Arne; Cooper, Alan; Willerslev, Eske; Orlando, Ludovic

    2016-08-27

    High-throughput sequencing has dramatically fostered ancient DNA research in recent years. Shotgun sequencing, however, does not necessarily appear as the best-suited approach due to the extensive contamination of samples with exogenous environmental microbial DNA. DNA capture-enrichment methods represent cost-effective alternatives that increase the sequencing focus on the endogenous fraction, whether it is from mitochondrial or nuclear genomes, or parts thereof. Here, we explored experimental parameters that could impact the efficacy of MYbaits in-solution capture assays of ~5000 nuclear loci or the whole genome. We found that varying quantities of the starting probes had only moderate effect on capture outcomes. Starting DNA, probe tiling, the hybridization temperature and the proportion of endogenous DNA all affected the assay, however. Additionally, probe features such as their GC content, number of CpG dinucleotides, sequence complexity and entropy and self-annealing properties need to be carefully addressed during the design stage of the capture assay. The experimental conditions and probe molecular features identified in this study will improve the recovery of genetic information extracted from degraded and ancient remains.

  14. Preventative and therapeutic probiotic use in allergic skin conditions: experimental and clinical findings.

    PubMed

    Özdemir, Öner; Erol, Azize Yasemin Göksu

    2013-01-01

    Probiotics are ingested live microbes that can modify intestinal microbial populations in a way that benefits the host. The interest in probiotic preventative/therapeutic potential in allergic diseases stemmed from the fact that probiotics have been shown to improve intestinal dysbiosis and permeability and to reduce inflammatory cytokines in human and murine experimental models. Enhanced presence of probiotic bacteria in the intestinal microbiota is found to correlate with protection against allergy. Therefore, many studies have been recently designed to examine the efficacy of probiotics, but the literature on the allergic skin disorders is still very scarce. Here, our objective is to summarize and evaluate the available knowledge from randomized or nonrandomized controlled trials of probiotic use in allergic skin conditions. Clinical improvement especially in IgE-sensitized eczema and experimental models such as atopic dermatitis-like lesions (trinitrochlorobenzene and picryl chloride sensitizations) and allergic contact dermatitis (dinitrofluorobenzene sensitization) has been reported. Although there is a very promising evidence to recommend the addition of probiotics into foods, probiotics do not have a proven role in the prevention or the therapy of allergic skin disorders. Thus, being aware of possible measures, such as probiotics use, to prevent/heal atopic diseases is essential for the practicing allergy specialist.

  15. Preventative and Therapeutic Probiotic Use in Allergic Skin Conditions: Experimental and Clinical Findings

    PubMed Central

    Özdemir, Öner; Göksu Erol, Azize Yasemin

    2013-01-01

    Probiotics are ingested live microbes that can modify intestinal microbial populations in a way that benefits the host. The interest in probiotic preventative/therapeutic potential in allergic diseases stemmed from the fact that probiotics have been shown to improve intestinal dysbiosis and permeability and to reduce inflammatory cytokines in human and murine experimental models. Enhanced presence of probiotic bacteria in the intestinal microbiota is found to correlate with protection against allergy. Therefore, many studies have been recently designed to examine the efficacy of probiotics, but the literature on the allergic skin disorders is still very scarce. Here, our objective is to summarize and evaluate the available knowledge from randomized or nonrandomized controlled trials of probiotic use in allergic skin conditions. Clinical improvement especially in IgE-sensitized eczema and experimental models such as atopic dermatitis-like lesions (trinitrochlorobenzene and picryl chloride sensitizations) and allergic contact dermatitis (dinitrofluorobenzene sensitization) has been reported. Although there is a very promising evidence to recommend the addition of probiotics into foods, probiotics do not have a proven role in the prevention or the therapy of allergic skin disorders. Thus, being aware of possible measures, such as probiotics use, to prevent/heal atopic diseases is essential for the practicing allergy specialist. PMID:24078929

  16. The Human Right to Adequate Housing: A Tool for Promoting and Protecting Individual and Community Health

    PubMed Central

    Thiele, Bret

    2002-01-01

    The human right to adequate housing is enshrined in international law. The right to adequate housing can be traced to the Universal Declaration of Human Rights, which was unanimously adopted by the world community in 1948. Since that time, the right to adequate housing has been reaffirmed on numerous occasions and further defined and elaborated. A key component of this right is habitability of housing, which should comply with health and safety standards. Therefore, the right to adequate housing provides an additional tool for advocates and others interested in promoting healthful housing and living conditions and thereby protecting individual and community health. PMID:11988432

  17. Experimental performance study of a proposed desiccant based air conditioning system.

    PubMed

    Bassuoni, M M

    2014-01-01

    An experimental investigation on the performance of a proposed hybrid desiccant based air conditioning system referred as HDBAC is introduced in this paper. HDBAC is mainly consisted of a liquid desiccant dehumidification unit integrated with a vapor compression system (VCS). The VCS unit has a cooling capacity of 5.27 kW and uses 134a as refrigerant. Calcium chloride (CaCl2) solution is used as the working desiccant material. HDBAC system is used to serve low sensible heat factor applications. The effect of different parameters such as, process air flow rate, desiccant solution flow rate, evaporator box and condenser box solution temperatures, strong solution concentration and regeneration temperature on the performance of the system is studied. The performance of the system is evaluated using some parameters such as: the coefficient of performance (COPa), specific moisture removal and energy saving percentage. A remarkable increase of about 54% in the coefficient of performance of the proposed system over VCS with reheat is achieved. A maximum overall energy saving of about 46% is observed which emphasizes the use of the proposed system as an energy efficient air conditioning system.

  18. Quantum Hall resistance standard in graphene devices under relaxed experimental conditions

    NASA Astrophysics Data System (ADS)

    Schopfer, F.; Ribeiro-Palau, R.; Lafont, F.; Brun-Picard, J.; Kazazis, D.; Michon, A.; Cheynis, F.; Couturaud, O.; Consejo, C.; Jouault, B.; Poirier, W.

    Large-area and high-quality graphene devices synthesized by CVD on SiC are used to develop reliable electrical resistance standards, based on the quantum Hall effect (QHE), with state-of-the-art accuracy of 1x10-9 and under an extended range of experimental conditions of magnetic field (down to 3.5 T), temperature (up to 10 K) or current (up to 0.5 mA). These conditions are much relaxed as compared to what is required by GaAs/AlGaAs standards and will enable to broaden the use of the primary quantum electrical standards to the benefit of Science and Industry for electrical measurements. Furthermore, by comparison of these graphene devices with GaAs/AlGaAs standards, we demonstrate the universality of the QHE within an ultimate uncertainty of 8.2x10-11. This suggests the exact relation of the quantized Hall resistance with the Planck constant and the electron charge, which is crucial for the new SI to be based on fixing such fundamental constants. These results show that graphene realizes its promises and demonstrates its superiority over other materials for a demanding application. Nature Nanotech. 10, 965-971, 2015, Nature Commun. 6, 6806, 2015

  19. Experimental insights on dissolution and transport of CO2 in marine sediments at hydrate forming conditions.

    NASA Astrophysics Data System (ADS)

    Bigalke, Nikolaus; Savy, Jean Philippe; Pansegrau, Moritz; Aloisi, Giovanni; Kossel, Elke; Haeckel, Matthias

    2010-05-01

    Various strategies are presently being discussed to reduce greenhouse gas emissions into the atmosphere. The idea to inject and store liquefied carbon dioxide in(to) marine sediments is particularly attractive for various reasons. Most convincing is the fact that carbon dioxide can be immobilized within the sediments if it reacts with the pore water to form a solid gas hydrate. However, current understanding of the large-scale technical feasibility of this prospect is still poor and requires accurate knowledge of the physicochemical processes following injection of the liquefied gas. High-pressure experiments designed to simulate the deep marine environment open the possibility to fill this knowledge gap. In this study, laboratory experiments were targeted at quantifying (a) the rate of carbon dioxide transfer across the two-phase interface (dissolution), (b) transport kinetics of dissolved carbon dioxide in a seawater-sediment mixture, and (c) formation of carbon dioxide hydrates within the sediment. Selecting experimental temperatures and pressures to conditions within and outside the carbon dioxide hydrate stability field (HSF) allowed highlighting the effect of hydrate presence on both, dissolution and transport kinetics. Concentration increase and hydrate presence were monitored by Raman spectroscopy. The experiments revealed anomalously fast transport rates of dissolved carbon dioxide at conditions both inside and outside the HSF. These first results could have major significance for safety-related issues in the discussion of carbon storage in the marine environment.

  20. Experimental performance study of a proposed desiccant based air conditioning system

    PubMed Central

    Bassuoni, M.M.

    2013-01-01

    An experimental investigation on the performance of a proposed hybrid desiccant based air conditioning system referred as HDBAC is introduced in this paper. HDBAC is mainly consisted of a liquid desiccant dehumidification unit integrated with a vapor compression system (VCS). The VCS unit has a cooling capacity of 5.27 kW and uses 134a as refrigerant. Calcium chloride (CaCl2) solution is used as the working desiccant material. HDBAC system is used to serve low sensible heat factor applications. The effect of different parameters such as, process air flow rate, desiccant solution flow rate, evaporator box and condenser box solution temperatures, strong solution concentration and regeneration temperature on the performance of the system is studied. The performance of the system is evaluated using some parameters such as: the coefficient of performance (COPa), specific moisture removal and energy saving percentage. A remarkable increase of about 54% in the coefficient of performance of the proposed system over VCS with reheat is achieved. A maximum overall energy saving of about 46% is observed which emphasizes the use of the proposed system as an energy efficient air conditioning system. PMID:25685475

  1. Frequency domain averaging based experimental evaluation of gear fault without tachometer for fluctuating speed conditions

    NASA Astrophysics Data System (ADS)

    Sharma, Vikas; Parey, Anand

    2017-02-01

    In the purview of fluctuating speeds, gear fault diagnosis is challenging due to dynamic behavior of forces. Various industrial applications employing gearbox which operate under fluctuating speed conditions. For diagnostics of a gearbox, various vibrations based signal processing techniques viz FFT, time synchronous averaging and time-frequency based wavelet transform, etc. are majorly employed. Most of the time, theories about data or computational complexity limits the use of these methods. In order to perform fault diagnosis of a gearbox for fluctuating speeds, frequency domain averaging (FDA) of intrinsic mode functions (IMFs) after their dynamic time warping (DTW) has been done in this paper. This will not only attenuate the effect of fluctuating speeds but will also extract the weak fault feature those masked in vibration signal. Experimentally signals were acquired from Drivetrain Diagnostic Simulator for different gear health conditions i.e., healthy pinion, pinion with tooth crack, chipped tooth and missing tooth and were analyzed for the different fluctuating profiles of speed. Kurtosis was calculated for warped IMFs before DTW and after DTW of the acquired vibration signals. Later on, the application of FDA highlights the fault frequencies present in the FFT of faulty gears. The result suggests that proposed approach is more effective towards the fault diagnosing with fluctuating speed.

  2. Determination of free vancomycin, ceftriaxone, cefazolin and ertapenem in plasma by ultrafiltration: impact of experimental conditions.

    PubMed

    Kratzer, Alexander; Liebchen, Uwe; Schleibinger, Michael; Kees, Martin G; Kees, Frieder

    2014-06-15

    Ultrafiltration is a rapid and convenient method to determine the free concentrations of drugs. In the present work, we aimed to develop an ultrafiltration method which is appropriate for routine determination of the free fraction of vancomycin and highly protein bound beta-lactams such as ertapenem, ceftriaxone and cefazolin in plasma from intensive care unit patients. Different filter types and experimental conditions (molecular weight cut-off, centrifugal force and time, pH, temperature) were evaluated and found to have influence on the result. In the final protocol, serum or plasma was buffered to pH 7.4-7.5, ultrafiltered at 1000×g at 37°C for 20min using Nanosep Omega 10K filters and subsequently analysed for the antibiotics by RP-HPLC with UV detection. The data from our investigation suggest to aim physiological conditions, i.e. 37°C and pH 7.4, and low to moderate relative centrifugal forces in order to get reliable results. With regard to the chromatographic separation, modulation of the pH in the range of 2.5-7.0 allows to determine several beta-lactams isocratically and/or to avoid interferences by co-administered drugs.

  3. Experimental fault tolerant universal quantum gates with solid-state spins under ambient conditions

    NASA Astrophysics Data System (ADS)

    Rong, Xing

    Quantum computation provides great speedup over classical counterpart for certain problems, such as quantum simulations, prime factoring and database searching. One of the challenges for realizing quantum computation is to execute precise control of the quantum system in the presence of noise. Recently, high fidelity control of spin-qubits has been achieved in several quantum systems. However, control of the spin-qubits with the accuracy required by the fault tolerant quantum computation under ambient conditions remains exclusive. Here we demonstrate a universal set of logic gates in nitrogen-vacancy centers with an average single-qubit gate fidelity of 0.99995 and two qubit gate fidelity of 0.992. These high control fidelities have been achieved in the C naturally abundant diamonds at room temperature via composite pulses and optimal control method. This experimental implementation of quantum gates with fault tolerant control fidelity sets an important step towards the fault-tolerant quantum computation under ambient conditions. National Key Basic Research Program of China (Grant No. 2013CB921800).

  4. 40 CFR 761.386 - Required experimental conditions for the validation study and subsequent use during decontamination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... experimental conditions apply for any solvent: (a) Temperature and pressure. Conduct the validation study and perform decontamination at room temperature (from ≥15 °C to ≤30 °C) and at atmospheric pressure....

  5. 40 CFR 761.386 - Required experimental conditions for the validation study and subsequent use during decontamination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... experimental conditions apply for any solvent: (a) Temperature and pressure. Conduct the validation study and perform decontamination at room temperature (from ≥15 °C to ≤30 °C) and at atmospheric pressure....

  6. 40 CFR 761.386 - Required experimental conditions for the validation study and subsequent use during decontamination.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... experimental conditions apply for any solvent: (a) Temperature and pressure. Conduct the validation study and perform decontamination at room temperature (from ≥15 °C to ≤30 °C) and at atmospheric pressure....

  7. 40 CFR 761.386 - Required experimental conditions for the validation study and subsequent use during decontamination.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... experimental conditions apply for any solvent: (a) Temperature and pressure. Conduct the validation study and perform decontamination at room temperature (from ≥15 °C to ≤30 °C) and at atmospheric pressure....

  8. 40 CFR 761.386 - Required experimental conditions for the validation study and subsequent use during decontamination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... experimental conditions apply for any solvent: (a) Temperature and pressure. Conduct the validation study and perform decontamination at room temperature (from ≥15 °C to ≤30 °C) and at atmospheric pressure....

  9. Measurement capability of field portable organic vapor monitoring instruments under different experimental conditions.

    PubMed

    Coffey, Christopher C; Pearce, Terri A; Lawrence, Robert B; Hudnall, Judith B; Slaven, James E; Martin, Stephen B

    2009-01-01

    The performance of field portable direct-reading organic vapor monitors (DROVMs) was evaluated under a variety of experimental conditions. Four of the DROVMs had photoionization detectors (ppbRAE, IAQRAE, MultiRAE, and Century Toxic Vapor Analyzer), one had a flame ionization detector (Century Toxic Vapor Analyzer), and one was a single-beam infrared spectrophotometer (SapphIRe). Four of each DROVM (two Century Toxic Vapor Analyzers and SapphIRes) were tested. The DROVMs were evaluated at three temperatures (4 degrees C, 21 degrees C, and 38 degrees C), three relative humidities (30%, 60%, and 90%), and two hexane concentrations (5 ppm and 100 ppm). These conditions were selected to provide a range within the operational parameters of all the instruments. At least four replicate trials were performed across the 18 experimental conditions (3 temperatures x 3 relative humidities x 2 concentrations). To evaluate performance, the 4-hr time-weighted average readings from the DROVMs in a given trial were compared with the average of two charcoal tube concentrations using pairwise comparison. The pairwise comparison criterion was +/-25% measurement agreement between each individual DROVM and the DROVMs as a group and the average charcoal tube concentration. The ppbRAE group performed the best with 40% of all readings meeting the comparison criterion followed by the SapphIRe group at 39%. Among individual DROVMs, the best performer was a SapphIRe, with 57% of its readings meeting the criterion. The data was further analyzed by temperature, humidity, and concentration. The results indicated the performance of some DROVMs may be affected by temperature, humidity, and/or concentration. The ppbRAE group performed best at 21 degrees C with the percentage of readings meeting the criterion increasing to 63%. At the 5 ppm concentration, 44% of the ppbRAE group readings met the criterion, while at 100 ppm, only 35% did. The results indicate that monitors can be used as survey tools

  10. Experimental results from containment piping bellows subjected to severe accident conditions: Results from bellows tested in corroded conditions. Volume 2

    SciTech Connect

    Lambert, L.D.; Parks, M.B.

    1995-10-01

    Bellows are an integral part of the containment pressure boundary in nuclear power plants. They are used at piping penetrations to allow relative movement between piping and the containment wall, while minimizing the load imposed on the piping and wall. Piping bellows are primarily used in steel containments; however, they have received limited use in some concrete (reinforced and prestressed) containments. In a severe accident they may be subjected to pressure and temperature conditions that exceed the design values, along with a combination of axial and lateral deflections. A test program to determine the leak-tight capacity of containment penetration bellows is being conducted at Sandia National Laboratories under the sponsorship of the US Nuclear Regulatory Commission. Several different bellows geometries, representative of actual containment bellows, have been subjected to extreme deflections along with pressure and temperature loads. The bellows geometries and loading conditions are described along with the testing apparatus and procedures. A total of nineteen bellows have been tested. Thirteen bellows were tested in ``like-new`` condition (results reported in Volume 1), and six were tested in a corroded condition. The tests showed that bellows in ``like-new`` condition are capable of withstanding relatively large deformations, up to, or near, the point of full compression or elongation, before developing leakage, while those in a corroded condition did not perform as well, depending on the amount of corrosion. The corroded bellows test program and results are presented in this report.

  11. Flow Control Under Low-Pressure Turbine Conditions Using Pulsed Jets: Experimental Data Archive

    NASA Technical Reports Server (NTRS)

    Volino, Ralph J.; Ibrahim, Mounir B.

    2012-01-01

    This publication is the final report of research performed under an NRA/Cooperative Interagency Agreement, and includes a supplemental CD-ROM with detailed data. It is complemented by NASA/CR-2012-217416 and NASA/CR-2012-217417 which include a Ph.D. Dissertation and an M.S. thesis respectively, performed under this contract. In this study the effects of unsteady wakes and flow control using vortex generator jets (VGJs) were studied experimentally and computationally on the flow over the L1A low pressure turbine (LPT) airfoil. The experimental facility was a six passage linear cascade in a low speed wind tunnel at the U.S. Naval Academy. In parallel, computational work using the commercial code FLUENT (ANSYS, Inc.) was performed at Cleveland State University, using Unsteady Reynolds Averaged Navier Stokes (URANS) and Large Eddy Simulations (LES) methods. In the first phase of the work, the baseline flow was documented under steady inflow conditions without flow control. URANS calculations were done using a variety of turbulence models. In the second phase of the work, flow control was added using steady and pulsed vortex generator jets. The VGJs successfully suppressed separation and reduced aerodynamic losses. Pulsed operation was more effective and mass flow requirements are very low. Numerical simulations of the VGJs cases showed that URANS failed to capture the effect of the jets. LES results were generally better. In the third phase, effects of unsteady wakes were studied. Computations with URANS and LES captured the wake effect and generally predicted separation and reattachment to match the experiments. Quantitatively the results were mixed. In the final phase of the study, wakes and VGJs were combined and synchronized using various timing schemes. The timing of the jets with respect to the wakes had some effect, but in general once the disturbance frequency was high enough to control separation, the timing was not very important. This is the supplemental CD-ROM

  12. Experimental study of the caprock / cement interface under CO2 geological storage conditions

    NASA Astrophysics Data System (ADS)

    Jobard, Emmanuel; Sterpenich, Jérôme; Pironon, Jacques; Randi, Aurélien; Caumon, Marie-Camille

    2013-04-01

    In the framework of CO2 geological storage, one of the critical point leading to possible massive CO2 leakages is the behavior of the interfaces crossed by the injection well. The lack of relevant data on the behavior of these interfaces (rock/well materials) in the presence of CO2 under high pressure and temperature conditions led to the development of a new experimental model called "Sandwich". These batch experiments consisted in putting a caprock (Callovo-Oxfordian claystone of the Paris Basin) in contact with cement (Portland class G) in the presence of supercritical CO2 with or without aqueous solution. The new experimental device was designed in order to follow the evolution of a clayey caprock, a Portland cement and their interface submitted to the acidic attack of carbonic acid through a study of the initial and final states. This model should help to document the behavior of interfaces in the proximal zone at the injection site. After one month of ageing at 80° C under 100 bar of CO2 pressure, the caprock, the cement and the interface between caprock and cement are investigated thanks to SEM, cathodoluminescence and Raman spectrometry. The main results reveal i) the influence of the presence of an aqueous solution since the carbonation mechanisms are quite different under dry and wet atmospheres, ii) the good cohesion of the different interfaces despite the carbonation of the cement, iii) the precipitation of different carbonate phases, which relates the changes in the chemistry of the solution to time, iv) the enrichment of silica in the cement phase submitted to the action of CO2 putting into evidence new mechanisms of in situ silica re-condensation, v) the very good behavior of the caprock despite the alkaline flux from cement and the acidic attack from the dissolved CO2. These experimental results will be compared to those obtained by geochemical simulations performed with PHREEQC. This study was financially supported by the French agency ANR (ANR-08

  13. Citrulline as a Biomarker for Gastrointestinal-Acute Radiation Syndrome: Species Differences and Experimental Condition Effects.

    PubMed

    Bujold, K; Hauer-Jensen, M; Donini, O; Rumage, A; Hartman, D; Hendrickson, H P; Stamatopoulos, J; Naraghi, H; Pouliot, M; Ascah, A; Sebastian, M; Pugsley, M K; Wong, K; Authier, S

    2016-07-01

    Animal models of hematopoietic and gastrointestinal acute radiation syndromes (ARS) have been characterized to develop medical countermeasures. Acute radiation-induced decrease of intestinal absorptive function has been correlated to a decrease in the number of intestinal crypt cells resulting from apoptosis and enterocyte mass reduction. Citrulline, a noncoded amino acid, is produced almost exclusively by the enterocytes of the small intestine. Citrullinemia has been identified as a simple, sensitive and suitable biomarker for radiation-induced injury associated with gastrointestinal ARS (GI-ARS). Here we discuss the effect of radiation on plasma citrulline levels in three different species, C57BL/6 mice, Göttingen minipigs and rhesus nonhuman primates (NHPs), measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). The effects of experimental study conditions such as feeding and anesthesia were also examined on plasma citrulline levels in the NHPs. Both the mice and Göttingen minipigs were partial-body irradiated (PBI) with doses from 13-17 Gy and 8-16 Gy, respectively, whereas NHPs were total-body irradiated (TBI) with doses from 6.72-13 Gy. Blood samples were taken at different time points and plasma citrulline levels were measured in the three species at baseline and after irradiation. Basal plasma citrulline concentrations (mean ± SEM) in mice and minipigs were 57.8 ± 2.8 μM and 63.1 ± 2.1 μM, respectively. NHPs showed a basal plasma citrulline concentration of 32.6 ± 0.7 μM, very similar to that of humans (∼40 μM). Plasma citrulline progressively decreased after irradiation, reaching nadir values between day 3.5 and 7. The onset of citrulline recovery was observed earlier at lower radiation doses, while only partial citrulline recovery was noted at higher radiation doses in minipigs and NHPs, complete recovery was noted in mice at all doses. Plasma citrulline levels in NHPs anesthetized with ketamine and acepromazine significantly

  14. Experimental Study on Fluid Distribution at Ultra-High Metamorphic Conditions

    NASA Astrophysics Data System (ADS)

    Mönicke, K.; Burchard, M.; Duyster, J.; Maresch, W. V.; Röller, K.; Stöckhert, B.

    2001-12-01

    Ultra-high pressure (UHP) metamorphic rocks record deep subduction of continental crust. Insight into their rheological behavior at UHP metamorphic conditions is important for the understanding of the mechanical state and the kinematics within subduction zones. Amazingly, many exhumed UHP metamorphic rocks do not show evidence of significant deformation. Thus, it has been proposed that deformation is localized in low-strength zones controlled by partially wetting interstitial fluids [1]. Experimental results [2] show that at UHP metamorphic conditions only one homogenous fluid phase with variable composition exists, whose density and viscosity should be intermediate between those of conventional aqueous solutions and hydrous melts. Inclusions of such supercritical fluid have been recently described from a natural UHP metamorphic rock [3]. Motivated by these findings, experiments using a piston-cylinder apparatus were performed to study the fluid distribution in various rock types at pressures of 3.5 GPa and temperatures between 900 ° C and 600 ° C. Starting materials were natural UHP metamorphic specimens of (1) S-type granitic biotite-phengite-gneiss and (2) pyrope-quartzite, both from the Dora Maira Massif (Western Alps, Italy) and (3) a diamond-bearing garnet-mica-gneiss with granodioritic bulk composition from the Saxonian Erzgebirge (Germany), all with 2 wt.% water added. The supercritical fluids formed in these experiments can be quenched to form a silicic glass with demixing of an aqueous solution without changing the UHP fluid topology significantly. The shape of the fluid-filled interstices is irregular and complex, resulting in a low volume/interface area ratio and a potential of high stress concentration at the edges of wedge-shaped offshoots. We propose that the distribution of supercritical fluids has a pronounced effect on the strength of cool subducted crust, allowing deformation by grain boundary sliding and dissolution precipitation creep, or

  15. Oligothiol graft-copolymer coatings stabilize gold nanoparticles against harsh experimental conditions.

    PubMed

    Kang, Jun Sung; Taton, T Andrew

    2012-12-11

    We report that poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) copolymers that bear multiple thiol groups on the polymer backbone are exceptional ligands for gold nanoparticles (AuNPs). In general, these graft copolymer ligands stabilize AuNPs against environments that would ordinarily lead to particle aggregation. To characterize the effect of copolymer structure on AuNP stability, we synthesized thiolated PLL-g-PEGs (PLL-g-[PEG:SH]) with different backbone lengths, PEG grafting densities, and number of thiols per polymer chain. AuNPs were then combined with these polymer ligands, and the stabilities of the resulting AuNP@PLL-g-[PEG:SH] particles against high temperature, oxidants, and competing thiol ligands were characterized using dynamic light scattering, visible absorption spectroscopy, and fluorescence spectrophotometry. Our observations indicate that thiolated PLL-g-PEG ligands combine thermodynamic stabilization via multiple Au-S bonds and steric stabilization by PEG grafts, and the best graft copolymer ligands balance these two effects. We hope that this new ligand system enables AuNPs to be applied to biotechnological applications that require harsh experimental conditions.

  16. Evolution of fracture permeability of ultramafic rocks undergoing serpentinization at hydrothermal conditions: An experimental study

    USGS Publications Warehouse

    Farough, Aida; Moore, Diane E.; Lockner, David A.; Lowell, R. P.

    2016-01-01

    We performed flow-through laboratory experiments on five cylindrically cored samples of ultramafic rocks, in which we generated a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at a confining pressure of 50 MPa, pore pressure of 20 MPa, and temperature of 260°C, simulating a depth of 2 km under hydrostatic conditions. A pore pressure difference of up to 2 MPa was imposed across the ends of the sample. Fracture permeability decreased by 1–2 orders of magnitude during the 200–330 h experiments. Electron microprobe and SEM data indicated the formation of needle-shaped crystals of serpentine composition along the walls of the fracture, and chemical analyses of sampled pore fluids were consistent with dissolution of ferro-magnesian minerals. By comparing the difference between fracture permeability and matrix permeability measured on intact samples of the same rock types, we concluded that the contribution of the low matrix permeability to flow is negligible and essentially all of the flow is focused in the tensile fracture. The experimental results suggest that the fracture network in long-lived hydrothermal circulation systems can be sealed rapidly as a result of mineral precipitation, and generation of new permeability resulting from a combination of tectonic and crystallization-induced stresses is required to maintain fluid circulation.

  17. Daily regulation of body temperature rhythm in the camel (Camelus dromedarius) exposed to experimental desert conditions.

    PubMed

    Bouâouda, Hanan; Achâaban, Mohamed R; Ouassat, Mohammed; Oukassou, Mohammed; Piro, Mohamed; Challet, Etienne; El Allali, Khalid; Pévet, Paul

    2014-09-01

    In the present work, we have studied daily rhythmicity of body temperature (Tb) in Arabian camels challenged with daily heat, combined or not with dehydration. We confirm that Arabian camels use heterothermy to reduce heat gain coupled with evaporative heat loss during the day. Here, we also demonstrate that this mechanism is more complex than previously reported, because it is characterized by a daily alternation (probably of circadian origin) of two periods of poikilothermy and homeothermy. We also show that dehydration induced a decrease in food intake plays a role in this process. Together, these findings highlight that adaptive heterothermy in the Arabian camel varies across the diurnal light-dark cycle and is modulated by timing of daily heat and degrees of water restriction and associated reduction of food intake. The changed phase relationship between the light-dark cycle and the Tb rhythm observed during the dehydration process points to a possible mechanism of internal desynchronization during the process of adaptation to desert environment. During these experimental conditions mimicking the desert environment, it will be possible in the future to determine if induced high-amplitude ambient temperature (Ta) rhythms are able to compete with the zeitgeber effect of the light-dark cycle.

  18. An experimental investigation of copper-Zircaloy interactions under possible tuff repository conditions

    SciTech Connect

    Smith, H D

    1990-05-01

    As part of its evaluation of copper and copper alloys for use as a container material for spent fuel, the Nevada Nuclear Waste Storage Investigations Project sponsored this experimental study to determine if the presence of copper would influence the corrosion rate of Zircaloy spent fuel cladding under possible tuff repository conditions. The experiment consisted of exposing copper/Zircaloy clad spent fuel packages to two different environments for up to 9 months. Detailed evaluation of the cladding via metallography, electron probe microanalysis, scanning electron microscopy with microanalysis, and Auger electron spectroscopy/ion milling to chemically profile the surface film failed to provide an evidence of copper-enhanced corrosion of the Zircaloy cladding. The difference in thickness of the oxide films between the 2-month and 5-month experiments, and the 2-month and 9-month experiments as indicated by the time to ion mill through the films, was on the order of 50 {angstrom}, and 100 {angstrom}, respectively, indicating a very low rate of film growth during the experiments. 20 refs., 21 figs., 8 tabs.

  19. Experimental and Computational Assessment of Conditionally Essential Genes in Escherichia coli▿

    PubMed Central

    Joyce, Andrew R.; Reed, Jennifer L.; White, Aprilfawn; Edwards, Robert; Osterman, Andrei; Baba, Tomoya; Mori, Hirotada; Lesely, Scott A.; Palsson, Bernhard Ø.; Agarwalla, Sanjay

    2006-01-01

    Genome-wide gene essentiality data sets are becoming available for Escherichia coli, but these data sets have yet to be analyzed in the context of a genome scale model. Here, we present an integrative model-driven analysis of the Keio E. coli mutant collection screened in this study on glycerol-supplemented minimal medium. Out of 3,888 single-deletion mutants tested, 119 mutants were unable to grow on glycerol minimal medium. These conditionally essential genes were then evaluated using a genome scale metabolic and transcriptional-regulatory model of E. coli, and it was found that the model made the correct prediction in ∼91% of the cases. The discrepancies between model predictions and experimental results were analyzed in detail to indicate where model improvements could be made or where the current literature lacks an explanation for the observed phenotypes. The identified set of essential genes and their model-based analysis indicates that our current understanding of the roles these essential genes play is relatively clear and complete. Furthermore, by analyzing the data set in terms of metabolic subsystems across multiple genomes, we can project which metabolic pathways are likely to play equally important roles in other organisms. Overall, this work establishes a paradigm that will drive model enhancement while simultaneously generating hypotheses that will ultimately lead to a better understanding of the organism. PMID:17012394

  20. Experimental study of tyre/road contact forces in rolling conditions for noise prediction

    NASA Astrophysics Data System (ADS)

    Cesbron, Julien; Anfosso-Lédée, Fabienne; Duhamel, Denis; Ping Yin, Hai; Le Houédec, Donatien

    2009-02-01

    This paper deals with the experimental study of dynamical tyre/road contact for noise prediction. In situ measurements of contact forces and close proximity noise levels were carried out for a slick tyre rolling on six different road surfaces between 30 and 50 km/h. Additional texture profiles of the tested surfaces were taken on the wheel track. Normal contact stresses were measured at a sampling frequency of 10752 Hz using a line of pressure sensitive cells placed both along and perpendicular to the rolling direction. The contact areas obtained during rolling were smaller than in static conditions. This is mainly explained by the dynamical properties of tyre compounds, like the viscoelastic behaviour of the rubber. Additionally the root-mean-square of the resultant contact forces at various speeds was in the same order for a given road surface, while their spectra were quite different. This is certainly due to a spectral influence of bending waves propagating in the tyre during rolling, especially when the wavelength is small in comparison with the size of the contact patch. Finally, the levels of contact forces and close proximity noise measured at 30 km/h were correlated. Additional correlations with texture levels were performed. The results show that the macro-texture generates contact forces linearly around 800 Hz and consequently noise levels between 500 and 1000 Hz via the vibrations transmitted to the tyre.

  1. Experimental demonstration of quantitation errors in MR spectroscopy resulting from saturation corrections under changing conditions

    NASA Astrophysics Data System (ADS)

    Galbán, Craig J.; Ellis, Scott J.; Spencer, Richard G. S.

    2003-04-01

    Metabolite concentration measurements in in vivo NMR are generally performed under partially saturated conditions, with correction for partial saturation performed after data collection using a measured saturation factor. Here, we present an experimental test of the hypothesis that quantitation errors can occur due to application of such saturation factor corrections in changing systems. Thus, this extends our previous theoretical work on quantitation errors due to varying saturation factors. We obtained results for two systems frequently studied by 31P NMR, the ischemic rat heart and the electrically stimulated rat gastrocnemius muscle. The results are interpreted in light of previous theoretical work which defined the degree of saturation occurring in a one-pulse experiment for a system with given spin-lattice relaxation times, T1s, equilibrium magnetizations, M0s, and reaction rates. We found that (i) the assumption of constancy of saturation factors leads to quantitation errors on the order of 40% in inorganic phosphate; (ii) the dominant contributor to the quantitation errors in inorganic phosphate is most likely changes in T1; (iii) T1 and M0 changes between control and intervention periods, and chemical exchange contribute to different extents to quantitation errors in phosphocreatine and γ-ATP; (iv) relatively small increases in interpulse delay substantially decreased quantitation errors for metabolites in ischemic rat hearts; (v) random error due to finite SNR led to approximately 4% error in quantitation, and hence was a substantially smaller contributor than were changes in saturation factors.

  2. An experimental study of the response of the Galesville sandstone to simulated CAES conditions

    SciTech Connect

    Erikson, R L; Stottlemyre, J A; Smith, R P

    1980-07-01

    The objective of this experimental study was to determine how the mineralogical and physical characteristics of host rock formations are affected by environmental conditions anticipated for compressed air energy storage (CAES) in porous, permeable rock. In this study, Galesville sandstone cores were reacted in autoclave pressure vessels supporting one of four environments: dry air; heated, air-water vapor; heated, nitrogen-water vapor mixtures; and heated, compressed, liquid water. The simulated CAES environments were maintained in autoclave pressure vessels by controlling the following independent variables: temperature, pressure, time, oxygen content, carbon dioxide content, nitrogen content, and liquid volume. The dependent variables studied were: apparent porosity, gas permeability, water permeability, and friability. These variables were measured at ambient temperature and pressure before and after each sandstone sample was reacted in one of the CAES environments. The experiments gave the following results: the Galesville sandstone exhibited excellent stability in dry air at all temperatures tested (50/sup 0/ to 300/sup 0/C); and significant physical alterations occurred in sandstone samples exposed to liquid water above 150/sup 0/C. Samples shielded from dripping water exhibited excellent stability to 300/sup 0/C; sandstone may be a suitable storage media for heated, humid air provided elevated temperature zones are relatively free of mobile liquid water; and observed changes in the physical properties of the rock may have been caused, in part, by the lack of confining stress on the sample. The inability to apply confining pressure is a severe limitation of autoclave experiments.

  3. Influence of experimental conditions on data variability in the liver comet assay.

    PubMed

    Guérard, M; Marchand, C; Plappert-Helbig, U

    2014-03-01

    The in vivo comet assay has increasingly been used for regulatory genotoxicity testing in recent years. While it has been demonstrated that the experimental execution of the assay, for example, electrophoresis or scoring, can have a strong impact on the results; little is known on how initial steps, that is, from tissue sampling during necropsy up to slide preparation, can influence the comet assay results. Therefore, we investigated which of the multitude of steps in processing the liver for the comet assay are most critical. All together eight parameters were assessed by using liver samples of untreated animals. In addition, two of those parameters (temperature and storage time of liver before embedding into agarose) were further investigated in animals given a single oral dose of ethyl methanesulfonate at dose levels of 50, 100, and 200 mg/kg, 3 hr prior to necropsy. The results showed that sample cooling emerged as the predominant influence factor, whereas variations in other elements of the procedure (e.g., size of the liver piece sampled, time needed to process the liver tissue post-mortem, agarose temperature, or time of lysis) seem to be of little relevance. Storing of liver samples of up to 6 hr under cooled conditions did not cause an increase in tail intensity. In contrast, storing the tissue at room temperature, resulted in a considerable time-dependent increase in comet parameters.

  4. Experimental study of the reaction of methane with petroleum hydrocarbons in geological conditions

    NASA Astrophysics Data System (ADS)

    Gold, Thomas; Gordon, Benjamin E.; Streett, William; Bilson, Elizabeth; Patnaik, Pradyot

    1986-11-01

    In order to assess the possible role of methane in petroleum formation, we studied the reaction of methane with liquid hydrocarbons representing the three main classes of compounds dominant in crude oil. The experimental reaction conditions simulated those of a geological setting for petroleum formations, at 1000 atm and 150-250°C in the presence of montmorillonite, a natural clay catalyst. Since we expected very slow reaction rates and thus low yields, we used 14C labeled methane to trace the reaction products. We report here the detection of ethylbenzene and ethyltoluene formed by the interaction of methane with benzene and toluene, respectively. Instead of methylation of benzene, predominantly C 2 addition occurred, although very small amounts of products corresponding to C 1 addition were also detected. We propose that catalytic dissociation of methane occurred, forming ethylene which participated in a Friedel-Crafts type alkylation process of the aromatic ring on the catalyst surface. In addition to ring alkylation, side reactions such as polymerization of unsaturates (ethylene, acetylene) appeared to have occurred on the catalyst surface. The nature of these polymers is yet to be determined.

  5. Experimental study of the reaction of methane with petroleum hydrocarbons in geological conditions

    SciTech Connect

    Gold, T.; Gordon, B.E.; Streett, W.; Bilson, E.; Patnaik, P.

    1986-11-01

    In order to assess the possible role of methane in petroleum formation, they studied the reaction of methane with liquid hydrocarbons representing the three main classes of compounds dominant in crude oil. The experimental reaction conditions simulated those of a geological setting for petroleum formations, at 1000 atm and 150-250/sup 0/C in the presence of montmorillonite, a natural clay catalyst. Since they expected very slow reaction rates and thus low yields, we used /sup 14/C labeled methane to trace the reaction products. They report here the detection of ethylbenzene and ethyltoluene formed by the interaction of methane with benzene and toluene, respectively. Instead of methylation of benzene, predominantly C/sub 2/ addition occurred, although very small amounts of products corresponding to C/sub 1/ addition were also detected. They propose that catalytic dissociation of methane occurred, forming ethylene which participated in a Friedel-Crafts type alkylation process of the aromatic ring on the catalyst surface. In addition to ring alkylation, side reactions such as polymerization of unsaturates (ethylene, acetylene) appeared to have occurred on the catalyst surface. The nature of these polymers is yet to be determined.

  6. Daily regulation of body temperature rhythm in the camel (Camelus dromedarius) exposed to experimental desert conditions

    PubMed Central

    Bouâouda, Hanan; Achâaban, Mohamed R.; Ouassat, Mohammed; Oukassou, Mohammed; Piro, Mohamed; Challet, Etienne; El Allali, Khalid; Pévet, Paul

    2014-01-01

    Abstract In the present work, we have studied daily rhythmicity of body temperature (Tb) in Arabian camels challenged with daily heat, combined or not with dehydration. We confirm that Arabian camels use heterothermy to reduce heat gain coupled with evaporative heat loss during the day. Here, we also demonstrate that this mechanism is more complex than previously reported, because it is characterized by a daily alternation (probably of circadian origin) of two periods of poikilothermy and homeothermy. We also show that dehydration induced a decrease in food intake plays a role in this process. Together, these findings highlight that adaptive heterothermy in the Arabian camel varies across the diurnal light–dark cycle and is modulated by timing of daily heat and degrees of water restriction and associated reduction of food intake. The changed phase relationship between the light–dark cycle and the Tb rhythm observed during the dehydration process points to a possible mechanism of internal desynchronization during the process of adaptation to desert environment. During these experimental conditions mimicking the desert environment, it will be possible in the future to determine if induced high‐amplitude ambient temperature (Ta) rhythms are able to compete with the zeitgeber effect of the light–dark cycle. PMID:25263204

  7. Influence of large-scale motion on turbulent transport for confined coaxial jets. Volume 1: Analytical analysis of the experimental data using conditional sampling

    NASA Technical Reports Server (NTRS)

    Brondum, D. C.; Bennett, J. C.

    1986-01-01

    The existence of large scale coherent structures in turbulent shear flows has been well documented. Discrepancies between experimental and computational data suggest a necessity to understand the roles they play in mass and momentum transport. Using conditional sampling and averaging on coincident two component velocity and concentration velocity experimental data for swirling and nonswirling coaxial jets, triggers for identifying the structures were examined. Concentration fluctuation was found to be an adequate trigger or indicator for the concentration-velocity data, but no suitable detector was located for the two component velocity data. The large scale structures are found in the region where the largest discrepancies exist between model and experiment. The traditional gradient transport model does not fit in this region as a result of these structures. The large scale motion was found to be responsible for a large percentage downstream at approximately the mean velocity of the overall flow in the axial direction. The radial mean velocity of the structures was found to be substantially greater than that of the overall flow.

  8. Effect of varying experimental conditions on the viscosity of α-pinene derived secondary organic material

    NASA Astrophysics Data System (ADS)

    Grayson, J. W.; Zhang, Y.; Mutzel, A.; Renbaum-Wolff, L.; Böge, O.; Kamal, S.; Herrmann, H.; Martin, S. T.; Bertram, A. K.

    2015-11-01

    To predict the role of secondary organic material (SOM) particles in climate, visibility, and health, information on the viscosity of particles containing SOM is required. In this study we investigate the viscosity of SOM particles as a function of relative humidity and SOM particle mass concentration during SOM synthesis. The SOM was generated via the ozonolysis of α-pinene at < 5 % relative humidity (RH). Experiments were carried out using the poke-and-flow technique, which measures the experimental flow time (τexp, flow) of SOM after poking the material with a needle. In the first set of experiments, we show that τexp, flow increased by a factor of 3600 as the RH increased from < 0.5 to 50 % RH, for SOM with a production mass concentration of 121 μg m-3. Based on simulations, the viscosities of the particles were between 6 × 105 and 5 × 107 Pa s at < 0.5 % RH and between 3 × 102 and 9 × 103 Pa s at 50 % RH. In the second set of experiments we show that under dry conditions τexp, flow decreased by a factor of 45 as the production mass concentration increased from 121 to 14 000 μg m-3. From simulations of the poke-and-flow experiments, the viscosity of SOM with a production mass concentration of 14 000 μg m-3 was determined to be between 4 × 104 and 1.5 × 106 Pa s compared to between 6 × 105 and 5 × 107 Pa s for SOM with a production mass concentration of 121 μg m-3. The results can be rationalised by a dependence of the chemical composition of SOM on production conditions. These results emphasise the shifting characteristics of SOM, not just with RH and precursor type, but also with the production conditions, and suggest that production mass concentration and the RH at which the viscosity was determined should be considered both when comparing laboratory results and when extrapolating these results to the atmosphere.

  9. Effect of varying experimental conditions on the viscosity of α-pinene derived secondary organic material

    NASA Astrophysics Data System (ADS)

    Grayson, James W.; Zhang, Yue; Mutzel, Anke; Renbaum-Wolff, Lindsay; Boge, Olaf; Kamal, Saeid; Herrmann, Hartmut; Martin, Scot T.; Bertram, Allan K.

    2016-05-01

    Knowledge of the viscosity of particles containing secondary organic material (SOM) is useful for predicting reaction rates and diffusion in SOM particles. In this study we investigate the viscosity of SOM particles as a function of relative humidity and SOM particle mass concentration, during SOM synthesis. The SOM was generated via the ozonolysis of α-pinene at < 5 % relative humidity (RH). Experiments were carried out using the poke-and-flow technique, which measures the experimental flow time (τexp, flow) of SOM after poking the material with a needle. In the first set of experiments, we show that τexp, flow increased by a factor of 3600 as the RH increased from < 0.5 RH to 50 % RH, for SOM with a production mass concentration of 121 μg m-3. Based on simulations, the viscosities of the particles were between 6 x 105 and 5 x 107 Pa s at < 0.5 % RH and between 3 x 102 and 9 x 103 Pa s at 50 % RH. In the second set of experiments we show that under dry conditions τexp, flow decreased by a factor of 45 as the production mass concentration increased from 121 to 14 000 μg m-3. From simulations of the poke-and-flow experiments, the viscosity of SOM with a production mass concentration of 14 000 μg m-3 was determined to be between 4 x 104 and 1.5 x 106 Pa s compared to between 6 x 105 and 5 x 107 Pa s for SOM with a production mass concentration of 121 μg m-3. The results can be rationalized by a dependence of the chemical composition of SOM on production conditions. These results emphasize the shifting characteristics of SOM, not just with RH and precursor type, but also with the production conditions, and suggest that production mass concentration and the RH at which the viscosity was determined should be considered both when comparing laboratory results and when extrapolating these results to the atmosphere.

  10. The National Ignition Facility: an experimental platform for studying behavior of matter under extreme conditions

    NASA Astrophysics Data System (ADS)

    Moses, Edward

    2011-11-01

    The National Ignition Facility (NIF), a 192-beam Nd-glass laser facility capable of producing 1.8 MJ and 500 TW of ultraviolet light, is now operational at Lawrence Livermore National Laboratory (LLNL). As the world's largest and most energetic laser system, NIF serves as the national center for the U.S. Department of Energy (DOE) and National Nuclear Security Administration to achieve thermonuclear burn in the laboratory and to explore the behavior of matter at extreme temperatures and energy densities. By concentrating the energy from all of its 192 extremely energetic laser beams into a mm3-sized target, NIF can reach the conditions required to initiate fusion reactions. NIF can also provide access to extreme scientific environments: temperatures about 100 million K, densities of 1,000 g/cm3, and pressures 100 billion times atmospheric pressure. These conditions have never been created before in a laboratory and exist naturally only in interiors of the planetary and stellar environments as well as in nuclear weapons. Since August 2009, the NIF team has been conducting experiments in support of the National Ignition Campaign (NIC)—a partnership among LLNL, Los Alamos National Laboratory, General Atomics, the University of Rochester, Sandia National Laboratories, as well as a number of universities and international collaborators. The results from these initial experiments show promise for the relatively near-term achievement of ignition. Capsule implosion experiments at energies up to 1.2 MJ have demonstrated laser energetics, radiation temperatures, and symmetry control that scale to ignition conditions. Of particular importance is the demonstration of peak hohlraum temperatures near 300 eV with overall backscatter less than 10%. Cryogenic target capability and additional diagnostics are being installed in preparation for layered target deuterium-tritium implosions to be conducted later in 2010. Important national security and basic science experiments have

  11. Formation of As(II)-pyrite during experimental replacement of magnetite under hydrothermal conditions

    NASA Astrophysics Data System (ADS)

    Qian, Gujie; Brugger, Joël; Testemale, Denis; Skinner, William; Pring, Allan

    2013-01-01

    A 'new' type of arsenian pyrite was formed during experimental replacement of magnetite under hydrothermal conditions (T = 125 and 220 °C; Psat) and in the presence of S(-II) and various As-containing species. The amount of As in pyrite depended on the As-source, with sources containing cationic As (As(II), As(III) and As(V)) resulting in considerably higher amounts of As in the product arsenian pyrite than anionic sources. The highest As content was 23.83 ± 0.20 wt%, corresponding to a S:Fe:As molar ratio of 2:0.58:0.42. Electron probe micro-analyses revealed an inverse correlation between the Fe and As contents in the arsenian pyrite, indicating that As is substituting for Fe. Arsenic concentrations were highly inhomogeneous within the pyrite rim; in general, higher As contents were found within solid pyrite growing on the outer rim, compared to the highly porous and texturally complex pyrite found close to the reaction boundary. This likely reflects different uptake mechanisms for As during the pyrite nucleation and growth stages. X-ray Absorption Near Edge Structure (XANES) analyses showed that the As in the arsenian pyrite was predominantly in the form of As(II). Cross-sectional X-ray photoelectron spectroscopy (XPS) analysis of the arsenian pyrite confirmed the presence of As(II), but also showed evidence for more oxidized species (As(III) and As(V) oxides), as well as small amounts of polymeric As-As bonding. This indicates a large difference between As in the bulk (XANES measurements) and at the pyrite surface (XPS). Ab initio XANES calculations are consistent with As replacing Fe in pyrite in the form of As(II). Our experimental study suggests that the formal oxidation state of As in this type of arsenian pyrite is close to +2, and that in addition to fluid composition and oxidation state, the reaction path leading to pyrite formation plays a significant role in controlling the chemistry of arsenian pyrite.

  12. Experimental and computational investigation of supersonic counterflow jet interaction in atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Ivanchenko, Oleksandr

    The flow field generated by the interaction of a converging-diverging nozzle (exit diameter, D=26 mm M=1.5) flow and a choked flow from a minor jet (exit diameter, d=2.6 mm) in a counterflow configuration was investigated. During the tests both the main C-D nozzle and the minor jet stagnation pressures were varied as well as the region of interaction. Investigations were made in the near field, at most about 2D distance, and in the far field, where the repeated patterns of shock waves were eliminated by turbulence. Both nozzles exhausted to the atmospheric pressure conditions. The flow physics was studied using Schlieren imaging techniques, Pitot-tube, conical Mach number probe, Digital Particle Image Velocimetry (DPIV) and acoustic measurement methods. During the experiments in the far field the jets interaction was observed as the minor jet flow penetrates into the main jet flow. The resulting shock structure caused by the minor jet's presence was dependent on the stagnation pressure ratio between the two jets. The penetration length of the minor jet into the main jet was also dependent on the stagnation pressure ratio. In the far field, increasing the minor jet stagnation pressure moved the bow shock forward, towards the main jet exit. In the near field, the minor jet flow penetrates into the main jet flow, and in some cases modified the flow pattern generated by the main jet, revealing a new effect of jet flow interaction that was previously unknown. A correlation function between the flow modes and the jet stagnation pressure ratios was experimentally determined. Additionally the flow interaction between the main and minor jets was simulated numerically using FLUENT. The optimal mesh geometry was found and the k-epsilon turbulence model was defined as the best fit. The results of the experimental and computational studies were used to describe the shock attenuation effect as self-sustain oscillations in supersonic flow. The effects described here can be used

  13. Investigation of Rayleigh-Taylor turbulence and mixing using direct numerical simulation with experimentally-measured initial conditions. I. Comparison to experimental data

    SciTech Connect

    Mueschke, N; Schilling, O

    2008-07-23

    A 1152 x 760 x 1280 direct numerical simulation (DNS) using initial conditions, geometry, and physical parameters chosen to approximate those of a transitional, small Atwood number Rayleigh-Taylor mixing experiment [Mueschke, Andrews and Schilling, J. Fluid Mech. 567, 27 (2006)] is presented. The density and velocity fluctuations measured just off of the splitter plate in this buoyantly unstable water channel experiment were parameterized to provide physically-realistic, anisotropic initial conditions for the DNS. The methodology for parameterizing the measured data and numerically implementing the resulting perturbation spectra in the simulation is discussed in detail. The DNS model of the experiment is then validated by comparing quantities from the simulation to experimental measurements. In particular, large-scale quantities (such as the bubble front penetration hb and the mixing layer growth parameter {alpha}{sub b}), higher-order statistics (such as velocity variances and the molecular mixing parameter {theta}), and vertical velocity and density variance spectra from the DNS are shown to be in favorable agreement with the experimental data. Differences between the quantities obtained from the DNS and from experimental measurements are related to limitations in the dynamic range of scales resolved in the simulation and other idealizations of the simulation model. This work demonstrates that a parameterization of experimentally-measured initial conditions can yield simulation data that quantitatively agrees well with experimentally-measured low- and higher-order statistics in a Rayleigh-Taylor mixing layer. This study also provides resolution and initial conditions implementation requirements needed to simulate a physical Rayleigh-Taylor mixing experiment. In Part II [Mueschke and Schilling, Phys. Fluids (2008)], other quantities not measured in the experiment are obtained from the DNS and discussed, such as the integral- and Taylor-scale Reynolds numbers

  14. Experimental evaluation of insecticidal paints against Triatoma infestans (Hemiptera: Reduviidae), under natural climatic conditions

    PubMed Central

    Amelotti, Ivana; Catalá, Silvia S; Gorla, David E

    2009-01-01

    Background Triatoma infestans is the main vector of Chagas disease in the Gran Chaco region of South America. The traditional spraying technique used for the application of pyrethroid insecticides has shown low efficiency in the elimination of the vector species populations occupying peridomestic structures of rural houses in the endemic area of Argentina. As part of studies looking for better alternatives, we evaluated the residual effect of insecticidal paints on the mortality of fourth instar nymphs of T. infestans. Results The study was based on an experimental design that included two groups treated with an organophosphate (Inesfly 5A IGR™) and a pyrethroid (Inesfly 5A IGR NG™) formulations of the paint, that were applied on wood, cement blocks and adobe bricks under natural climatic conditions. A third group was an untreated control. Both paint formulations showed very long residual activity, producing mortality of 84% and 98% (pyrethroid and organophosphate formulations, respectively) after 12 months of the paint application. After eight months, nymphs exposed during 6 hours to the painted surfaces with the pyrethroid and organophosphate formulations showed 81.33% and 100% mortality, respectively. Conclusion The organophosphate- and pyrethroid-based insecticidal paints showed a very long residual activity on the mortality of fourth instar nymphs of T infestans, compared with the traditional spraying technique used for the application of pyrethroid insecticides in peridomestic structures of rural houses in the endemic region for Chagas disease in the Gran Chaco of Argentina. The application of the paints by trained personnel of the vector control programmes could be considered as an alternative control tool in areas where the traditional methods have failed or showed low efficacy. PMID:19586532

  15. SU-E-T-178: Experimental Study of Acceptable Movement Conditions for SBRT Lung Treatments

    SciTech Connect

    Carrasco de Fez, P; Ruiz-Martinez, A; Jornet, N; Eudaldo, T; Latorre-Musoll, A; Ribas, Morales M

    2014-06-01

    Purpose: To experimentally study the acceptable movement conditions for SBRT lung treatments we quantified with film dosimetry the change in dose distributions due to periodic movements of 5 different amplitudes and 4 respiratory gating duty cycles on a SBRT treatment plan. Methods: We planned a SBRT treatment plan for the QUASAR™ (Modus Medical) phantom equipped with the respiratory motion device. We placed a 3 mm water-equivalent sphere simulating a tumour inside the lung-equivalent insert. This sphere is divided in two hemispheres that allow placing films in between. We used radiochromic EBT2™ (Ashland) films. We oriented the lung insert in such a way that sagittal dose distributions could be measured. We applied a sinusoidal movement with 3 s period for 5 different amplitudes of 0(static), 5, 7, 10, 15 and 20 mm without gating. For the 20 mm amplitude we studied the gating technique with 4 duty cycles of 20, 40, 60 and 80% of the respiratory cycle. Each situation was irradiated in a Clinac 2100 linac (Varian) equipped with the RPM™ system. FilmQA Pro™ (Ashland) software together with an Expression 10000XL scanner (EPSON) were used to analyze and compare the measured dose distributions with those planned by the Eclipse™ TPS v. 8.9 (Varian) by means of gamma analysis with 6 criteria: 5%/3mm, 5%/2mm, 5%/1mm, 3%/3mm, 3%/2mm and 2%/2mm (threshold of 10%). Results: Movements with amplitude of less than 7mm do not significantly modified the dosimetry. Gating duty cycles of less than 40% yielded also acceptable results for a 2 cm amplitude movement. Conclusion: To safely perform daily accurate SBRT treatments, movements have to be restricted to 7 mm amplitude (±3.5 mm). Otherwise, a gating strategy should be considered.

  16. Aerosol transmission of foot-and-mouth disease virus Asia-1 under experimental conditions.

    PubMed

    Colenutt, C; Gonzales, J L; Paton, D J; Gloster, J; Nelson, N; Sanders, C

    2016-06-30

    Foot-and-mouth disease virus (FMDV) control measures rely on understanding of virus transmission mechanisms. Direct contact between naïve and infected animals or spread by contaminated fomites is prevented by quarantines and rigorous decontamination procedures during outbreaks. Transmission of FMDV by aerosol may not be prevented by these control measures and this route of transmission may allow infection of animals at distance from the infection source. Understanding the potential for aerosol spread of specific FMDV strains is important for informing control strategies in an outbreak. Here, the potential for transmission of an FMDV Asia 1 strain between pigs and cattle by indirect aerosol exposure was evaluated in an experimental setting. Four naïve calves were exposed to aerosols emitted from three infected pigs in an adjacent room for a 10h period. Direct contact between pigs and cattle and fomite transfer between rooms was prevented. Viral titres in aerosols emitted by the infected pigs were measured to estimate the dose that calves were exposed to. One of the calves developed clinical signs of FMD, whilst there was serological evidence for spread to cattle by aerosol transmission in the remaining three calves. This highlights the possibility that this FMDV Asia 1 strain could be spread by aerosol transmission given appropriate environmental conditions should an outbreak occur in pigs. Our estimates suggest the exposure dose required for aerosol transmission was higher than has been previously quantified for other serotypes, implying that aerosols are less likely to play a significant role in transmission and spread of this FMDV strain.

  17. Transcriptomic response of Argopecten purpuratus post-larvae to copper exposure under experimental conditions.

    PubMed

    Zapata, Manuel; Tanguy, Arnaud; David, Elise; Moraga, Dario; Riquelme, Carlos

    2009-08-01

    Few studies have described the molecular response of mollusk larvae to heavy metal exposure. We investigated the response of Chilean scallop Argopecten purpuratus post-larvae to copper exposure under experimental conditions. Post-larvae were maintained with and without copper stress in tanks containing netlon collectors with biofilms that were formed by the bacterium Halomonas sp. and the diatom Amphora sp., known to increase larval settlement. We focused on the analysis of the differential expression patterns of genes associated with copper response. A suppression subtractive hybridization method was used to identify copper-specific up- and down-regulated genes in the post-larvae following 4 days and 8 days exposure to 2.5 and 10 microg/l Cu(+2). This method revealed 145 different sequences corresponding to 10 major physiological functions. The expression of 15 potentially regulated genes was analyzed by real-time PCR in post-larvae at different sampling times during the copper stress. The genes chosen were alpha tubulin, elongation factor 1-alpha (EF1A), tributylin binding protein type 1 (TBT), NADH dehydrogenase subunit 2 (NADH2), cavortin, glutathione peroxidase (GPx), ferritin, heat shock protein 70 (HSP70), Pam highwire rpm1 (Phr1), insulin-like growth factor 1 (IGF1), cellulase, and ribosomal proteins: L18, L44, S3a and S15. This study contributes to the characterization of potential genetic markers that could be used in future environmental monitoring and to explore new mechanisms of stress tolerance in marine mollusk species, especially in early stages of development.

  18. Calibrated simulations of Z opacity experiments that reproduce the experimentally measured plasma conditions

    NASA Astrophysics Data System (ADS)

    Nagayama, T.; Bailey, J. E.; Loisel, G.; Rochau, G. A.; MacFarlane, J. J.; Golovkin, I.

    2016-02-01

    Recently, frequency-resolved iron opacity measurements at electron temperatures of 170-200 eV and electron densities of (0.7 - 4.0 )× 1022cm-3 revealed a 30 - 400 % disagreement with the calculated opacities [J. E. Bailey et al., Nature (London) 517, 56 (2015), 10.1038/nature14048]. The discrepancies have a high impact on astrophysics, atomic physics, and high-energy density physics, and it is important to verify our understanding of the experimental platform with simulations. Reliable simulations are challenging because the temporal and spatial evolution of the source radiation and of the sample plasma are both complex and incompletely diagnosed. In this article, we describe simulations that reproduce the measured temperature and density in recent iron opacity experiments performed at the Sandia National Laboratories Z facility. The time-dependent spectral irradiance at the sample is estimated using the measured time- and space-dependent source radiation distribution, in situ source-to-sample distance measurements, and a three-dimensional (3D) view-factor code. The inferred spectral irradiance is used to drive 1D sample radiation hydrodynamics simulations. The images recorded by slit-imaged space-resolved spectrometers are modeled by solving radiation transport of the source radiation through the sample. We find that the same drive radiation time history successfully reproduces the measured plasma conditions for eight different opacity experiments. These results provide a quantitative physical explanation for the observed dependence of both temperature and density on the sample configuration. Simulated spectral images for the experiments without the FeMg sample show quantitative agreement with the measured spectral images. The agreement in spectral profile, spatial profile, and brightness provides further confidence in our understanding of the backlight-radiation time history and image formation. These simulations bridge the static-uniform picture of the data

  19. Calibrated simulations of Z opacity experiments that reproduce the experimentally measured plasma conditions.

    PubMed

    Nagayama, T; Bailey, J E; Loisel, G; Rochau, G A; MacFarlane, J J; Golovkin, I

    2016-02-01

    Recently, frequency-resolved iron opacity measurements at electron temperatures of 170-200 eV and electron densities of (0.7-4.0)×10(22)cm(-3) revealed a 30-400% disagreement with the calculated opacities [J. E. Bailey et al., Nature (London) 517, 56 (2015)]. The discrepancies have a high impact on astrophysics, atomic physics, and high-energy density physics, and it is important to verify our understanding of the experimental platform with simulations. Reliable simulations are challenging because the temporal and spatial evolution of the source radiation and of the sample plasma are both complex and incompletely diagnosed. In this article, we describe simulations that reproduce the measured temperature and density in recent iron opacity experiments performed at the Sandia National Laboratories Z facility. The time-dependent spectral irradiance at the sample is estimated using the measured time- and space-dependent source radiation distribution, in situ source-to-sample distance measurements, and a three-dimensional (3D) view-factor code. The inferred spectral irradiance is used to drive 1D sample radiation hydrodynamics simulations. The images recorded by slit-imaged space-resolved spectrometers are modeled by solving radiation transport of the source radiation through the sample. We find that the same drive radiation time history successfully reproduces the measured plasma conditions for eight different opacity experiments. These results provide a quantitative physical explanation for the observed dependence of both temperature and density on the sample configuration. Simulated spectral images for the experiments without the FeMg sample show quantitative agreement with the measured spectral images. The agreement in spectral profile, spatial profile, and brightness provides further confidence in our understanding of the backlight-radiation time history and image formation. These simulations bridge the static-uniform picture of the data interpretation and the

  20. Calibrated simulations of Z opacity experiments that reproduce the experimentally measured plasma conditions

    DOE PAGES

    Nagayama, T.; Bailey, J. E.; Loisel, G.; ...

    2016-02-05

    Recently, frequency-resolved iron opacity measurements at electron temperatures of 170–200 eV and electron densities of (0.7 – 4.0) × 1022 cm–3 revealed a 30–400% disagreement with the calculated opacities [J. E. Bailey et al., Nature (London) 517, 56 (2015)]. The discrepancies have a high impact on astrophysics, atomic physics, and high-energy density physics, and it is important to verify our understanding of the experimental platform with simulations. Reliable simulations are challenging because the temporal and spatial evolution of the source radiation and of the sample plasma are both complex and incompletely diagnosed. In this article, we describe simulations that reproducemore » the measured temperature and density in recent iron opacity experiments performed at the Sandia National Laboratories Z facility. The time-dependent spectral irradiance at the sample is estimated using the measured time- and space-dependent source radiation distribution, in situ source-to-sample distance measurements, and a three-dimensional (3D) view-factor code. The inferred spectral irradiance is used to drive 1D sample radiation hydrodynamics simulations. The images recorded by slit-imaged space-resolved spectrometers are modeled by solving radiation transport of the source radiation through the sample. We find that the same drive radiation time history successfully reproduces the measured plasma conditions for eight different opacity experiments. These results provide a quantitative physical explanation for the observed dependence of both temperature and density on the sample configuration. Simulated spectral images for the experiments without the FeMg sample show quantitative agreement with the measured spectral images. The agreement in spectral profile, spatial profile, and brightness provides further confidence in our understanding of the backlight-radiation time history and image formation. Furthermore, these simulations bridge the static-uniform picture of the

  1. Experimental aqueous alteration of the Allende meteorite under oxidizing conditions: Constraints on asteroidal alteration

    NASA Astrophysics Data System (ADS)

    Jones, Catherine L.; Brearley, Adrian J.

    2006-02-01

    We have performed an experimental study of the aqueous alteration of the Allende CV3 carbonaceous chondrite under highly oxidizing conditions, in order to examine the alteration behavior of Allende's anhydrous mineralogy. The experiments were carried out at temperatures of 100, 150, and 200 °C, for time periods between 7 and 180 days, with water/rock ratios ranging from 1:1 to 9:1. Uncrushed cubes of Allende were used so that the spatial relationships between reactant and product phases could be examined in detail. Scanning electron microscope studies show that in all the experiments, even those of short duration (7 days), soluble salts of Ca and Mg (CaSO 4, CaCO 3, and MgSO 4) precipitated on the sample surface, indicating that these elements are rapidly mobilized during alteration. In addition, iron oxides and hydroxides formed on the sample surfaces. The sulfates, carbonates, and the majority of the iron-bearing secondary minerals are randomly distributed over the surface of samples. In some instances the iron oxides and hydroxides are constrained to the boundaries of altering mineral grains. Transmission electron microscope studies show that the FeO-rich olivine in the interior of the samples has altered to form interlayered serpentine/saponite and Fe-oxyhydroxides. The degree of alteration increases significantly with increasing water/rock ratio, and to a lesser extent with increasing duration of heating. The serpentine/saponite forms both by direct replacement of the olivine in crystallographically oriented intergrowths, and by recrystallization of an amorphous Si-rich phase that precipitates in pore space between the olivine grains. The alteration assemblage bears many similarities to those found in altered carbonaceous chondrites, although in detail there are important differences, which we attribute to (a) the relatively high temperatures of our experiments and (b) comparatively short reaction times compared with the natural examples. In terms of mineral

  2. Experimental evaluation of connectivity influence on dispersivity under confined and unconfined radial convergent flow conditions

    NASA Astrophysics Data System (ADS)

    Guzzi, Silvia; Molinari, Antonio; Fallico, Carmine; Pedretti, Daniele

    2014-05-01

    Heterogeneity and connectivity have a significant impact on the fate and transport of contaminants due to the occurrence of formations with largest permeability than the surrounding geological materials, which can originate preferential pathways in groundwater system. These issues are usually addressed by tracer tests and a radial convergent (RC) flow setting is typically selected for convenience but more complicated for model interpretation than uniform flow transport. An experimental investigation was performed using RC tracer tests in a 3D intermediate scale physical model to illustrate the role of connected features on the estimation of dispersivity using the classical Sauty solution and the method of moments, under confined and unconfined aquifer conditions. The physical model consists of 26 piezometers located at difference distances from a constant-discharge central pumping well. The box is filled with gravel channels embedded in a sandy matrix and organized in different layers. Materials have been well characterized before and after the test. For the confined configuration, a silt layer was placed above the previous layers. Tracer tests were performed using potassium iodide solutions with concentration of 3•10-3 M and under a constant pumping flow rate of 0.05 L/s. To mimic a pulse injection in each piezometer we used syringes and pipes, whereas a probe allowed continuous measuring of tracer concentration. Average velocity and longitudinal dispersion coefficient were defined from the first and second central moment of the observed breakthrough curves for each piezometer (integrated over the outflow boundary of the domain) and using the classical curve matching from the Sauty's solution at different Péclet numbers. Results reveal in some cases that estimates of hydrodynamic parameters from the Sauty solution and the method of moments seem to be different. This is related to the different basic assumptions of the two methods applied, and especially because

  3. Experimental Investigation of Soil and Atmospheric Conditions on the Momentum, Mass, and Thermal Boundary Layers Above the Land Atmosphere Interface

    NASA Astrophysics Data System (ADS)

    Trautz, A.; Smits, K. M.; Illangasekare, T. H.; Schulte, P.

    2014-12-01

    The purpose of this study is to investigate the impacts of soil conditions (i.e. soil type, saturation) and atmospheric forcings (i.e. velocity, temperature, relative humidity) on the momentum, mass, and temperature boundary layers. The atmospheric conditions tested represent those typically found in semi-arid and arid climates and the soil conditions simulate the three stages of evaporation. The data generated will help identify the importance of different soil conditions and atmospheric forcings with respect to land-atmospheric interactions which will have direct implications on future numerical studies investigating the effects of turbulent air flow on evaporation. The experimental datasets generated for this study were performed using a unique climate controlled closed-circuit wind tunnel/porous media facility located at the Center for Experimental Study of Subsurface Environmental Processes (CESEP) at the Colorado School of Mines. The test apparatus consisting of a 7.3 m long porous media tank and wind tunnel, were outfitted with a sensor network to carefully measure wind velocity, air and soil temperature, relative humidity, soil moisture, and soil air pressure. Boundary layer measurements were made between the heights of 2 and 500 mm above the soil tank under constant conditions (i.e. wind velocity, temperature, relative humidity). The soil conditions (e.g. soil type, soil moisture) were varied between datasets to analyze their impact on the boundary layers. Experimental results show that the momentum boundary layer is very sensitive to the applied atmospheric conditions and soil conditions to a much less extent. Increases in velocity above porous media leads to momentum boundary layer thinning and closely reflect classical flat plate theory. The mass and thermal boundary layers are directly dependent on both atmospheric and soil conditions. Air pressure within the soil is independent of atmospheric temperature and relative humidity - wind velocity and soil

  4. Experimental investigation on the photovoltaic-thermal solar heat pump air-conditioning system on water-heating mode

    SciTech Connect

    Fang, Guiyin; Hu, Hainan; Liu, Xu

    2010-09-15

    An experimental study on operation performance of photovoltaic-thermal solar heat pump air-conditioning system was conducted in this paper. The experimental system of photovoltaic-thermal solar heat pump air-conditioning system was set up. The performance parameters such as the evaporation pressure, the condensation pressure and the coefficient of performance (COP) of heat pump air-conditioning system, the water temperature and receiving heat capacity in water heater, the photovoltaic (PV) module temperature and the photovoltaic efficiency were investigated. The experimental results show that the mean photovoltaic efficiency of photovoltaic-thermal (PV/T) solar heat pump air-conditioning system reaches 10.4%, and can improve 23.8% in comparison with that of the conventional photovoltaic module, the mean COP of heat pump air-conditioning system may attain 2.88 and the water temperature in water heater can increase to 42 C. These results indicate that the photovoltaic-thermal solar heat pump air-conditioning system has better performances and can stably work. (author)

  5. Experimental study on the optimization of general conditions for a free-flow electrophoresis device with a thermoelectric cooler.

    PubMed

    Yan, Jian; Yang, Cheng-Zhang; Zhang, Qiang; Liu, Xiao-Ping; Kong, Fan-Zhi; Cao, Cheng-Xi; Jin, Xin-Qiao

    2014-12-01

    With a given free-flow electrophoresis device, reasonable conditions (electric field strength, carrier buffer conductivity, and flow rate) are crucial for an optimized separation. However, there has been no experimental study on how to choose reasonable general conditions for a free-flow electrophoresis device with a thermoelectric cooler in view of Joule heat generation. Herein, comparative experiments were carried out to propose the selection procedure of general conditions in this study. The experimental results demonstrated that appropriate conditions were (i) <67 V/cm electric field strength; (ii) lower than 1.3 mS/cm carrier buffer conductivity (Tris-HCl: 20 mM Tris was titrated by HCl to pH 8.0); and (iii) higher than 3.6 mL/min carrier buffer flow rate. Furthermore, under inappropriate conditions (e.g. 400 V voltage and 40 mM Tris-HCl carrier buffer), the free-flow electrophoresis separation would be destroyed by bubbles caused by more Joule heating. Additionally, a series of applications under the appropriate conditions were performed with samples of model dyes, proteins (bovine serum albumin, myoglobin, and cytochrome c), and cells (Escherichia coli, Streptococcus thermophilus, and Saccharomyces cerevisiae). The separation results showed that under the appropriate conditions, separation efficiency was obviously better than that in the previous experiments with randomly or empirically selected conditions.

  6. THE EFFECT OF EXPERIMENTAL ERROR ON THE DETERMINATION OF THE OPTIMUM METAL-CUTTING CONDITIONS.

    DTIC Science & Technology

    the uncertainty in the parameter-estimates of the tool-life equation. The confidence interval for V(min) depends on the magnitude of the cost-time...parameter t sub e; as t sub e increases, the V(min) confidence interval decreases. The confidence interval for V(min) is affected by the experimental...range of feed in tool-life testing; the smallest confidence interval is at the average experimental feed. A decision rule based on the minimax

  7. Validation of reference genes for RT-qPCR studies of gene expression in banana fruit under different experimental conditions.

    PubMed

    Chen, Lei; Zhong, Hai-ying; Kuang, Jian-fei; Li, Jian-guo; Lu, Wang-jin; Chen, Jian-ye

    2011-08-01

    Reverse transcription quantitative real-time PCR (RT-qPCR) is a sensitive technique for quantifying gene expression, but its success depends on the stability of the reference gene(s) used for data normalization. Only a few studies on validation of reference genes have been conducted in fruit trees and none in banana yet. In the present work, 20 candidate reference genes were selected, and their expression stability in 144 banana samples were evaluated and analyzed using two algorithms, geNorm and NormFinder. The samples consisted of eight sample sets collected under different experimental conditions, including various tissues, developmental stages, postharvest ripening, stresses (chilling, high temperature, and pathogen), and hormone treatments. Our results showed that different suitable reference gene(s) or combination of reference genes for normalization should be selected depending on the experimental conditions. The RPS2 and UBQ2 genes were validated as the most suitable reference genes across all tested samples. More importantly, our data further showed that the widely used reference genes, ACT and GAPDH, were not the most suitable reference genes in many banana sample sets. In addition, the expression of MaEBF1, a gene of interest that plays an important role in regulating fruit ripening, under different experimental conditions was used to further confirm the validated reference genes. Taken together, our results provide guidelines for reference gene(s) selection under different experimental conditions and a foundation for more accurate and widespread use of RT-qPCR in banana.

  8. Germination and Growth of a Vegetable Exposed to Very Severe Environmental Conditions Experimentally Induced by High Voltage

    NASA Astrophysics Data System (ADS)

    Aoki, Takashi; Ikezawa, Shunjiro

    1982-09-01

    Ultra-high-voltage (UHV) transmission power lines are required in order to reduce transmission energy losses, and to transfer more power across long distances. However, the ecological and biological influence of UHV lines has not been documented well. Possible influences of UHV lines are: electro-magnetic field, ozone, NOx, and ion shower. The purpose of this study was to obtain information on the germination and growth of Raphanus sativus L.cv. Kaiware-daikon exposed to an experimental environment in which all the above influences at very severe intensity levels were working simultaneously. Several environmental conditions severer than those predicted for future UHV lines were set up, using a high voltage at 60 Hz. The germination and growth of this plant were suppressed under the experimental conditions used, the suppression being greater the severer the conditions. When the electric field is strong, corona discharge occurs at the tip of the plant.

  9. Conditions for the Validity of Faraday's Law of Induction and Their Experimental Confirmation

    ERIC Educational Resources Information Center

    Lopez-Ramos, A.; Menendez, J. R.; Pique, C.

    2008-01-01

    This paper, as its main didactic objective, shows the conditions needed for the validity of Faraday's law of induction. Inadequate comprehension of these conditions has given rise to several paradoxes about the issue; some are analysed and solved in this paper in the light of the theoretical deduction of the induction law. Furthermore, an…

  10. Computational modeling and experimental validation of odor detection behaviours of classically conditioned parasitic wasp, Microplitis croceipes.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To further improve the sensitivity of odor¬ and odor concentration detection of the Wasp Hound, searching behaviors of a food-conditioned wasp in a confined area with the conditioning odor were recorded. The experiments were recorded using a video camera. First, the wasps are individually hand condi...

  11. The effects of scope condition-based participant exclusion on experimental outcomes in expectation states research: A meta-analysis.

    PubMed

    Dippong, Joseph

    2012-03-01

    Expectation states theory employs several scope statements to specify the situational conditions that must be met for any test of the theory to be considered valid (Foschi, 1997). Collective orientation and task orientation are two scope conditions that researchers frequently implement as selection criteria for a participant's inclusion in an analytic sample. Although excluding participants who fail to meet scope conditions is theoretically consistent, researchers have yet to establish how this practice affects experimental outcomes. I employ meta-analysis to compare studies within the expectation states tradition in which participants are excluded for failure to meet scope conditions to studies in which no similar exclusions are made. Results suggest that studies that exclude participants for scope violations demonstrate a decreased baseline tendency to reject influence. I contend that adopting a more universal approach to the measurement and application of scope conditions would be methodologically and theoretically beneficial to expectation states research.

  12. [Experimental evaluation of actoprotective activity of nitrogen-containing heterocyclic compounds derivatives in extreme conditions].

    PubMed

    Tsublova, E G; Ivanova, T G; Ivanova, T N; Iasnetsov, V V

    2013-07-01

    In experiments on nonlinear male mice the ability of new derivatives of nitrogen-containing heterocyclic compounds to increase the physical working capacity in conditions of hyperthermia, hypothermia and acute normobaric hypoxia and hypercapnia has been investigated. It is established, that pyridine derivative IBHF-11 has more expressed positive action in the said conditions. It provided increase of the working capacity of animals at all kinds of extreme influence, and the value of positive action was comparable, and in conditions of acute normobaric hypoxia and hypercapnia exceeded those at the reference products bemitil and bromantan.

  13. New experimental possibilities for measuring radiative opacity under conditions in the Sun's interior

    NASA Astrophysics Data System (ADS)

    Rose, S. J.

    2005-12-01

    Opacity experiments that have been conducted to date using long-pulse (nanosecond) high-power lasers have reached conditions similar in density and temperature to those found in the outer part of the radiative flow region of the Sun. Experiments using short-pulse (picosecond) lasers are beginning to give access to conditions halfway to the Sun's centre. In this paper we describe a preliminary design of an opacity experiment that uses a combination of long and short-pulse laser beams to compress and heat the plasma and thereby access conditions similar to those at the centre of the Sun.

  14. Analytical and experimental studies of ventilation systems subjected to simulated tornado conditions: Verification of the TVENT computer code

    SciTech Connect

    Martin, R.A.; Gregory, W.S.; Ricketts, C.I.; Smith, P.R.; Littleton, P.E.; Talbott, D.V.

    1988-04-01

    Analytical and experimental studies of ventilation systems have been conducted to verify the Los Alamos National Laboratory TVENT accident analysis computer code for simulated tornado conditions. This code was developed to be a user-friendly analysis tool for designers and regulatory personnel and was designed to predict pressure and flow transients in arbitrary ventilation systems. The experimental studies used two relatively simple, yet sensitive, physical systems designed using similitude analysis. These physical models were instrumented end-to-end for pressure and volumetric flow rate and then subjected to the worst credible tornado conditions using a special blowdown apparatus. We verified TVENT by showing that it successfully predicted our experimental results. By comparing experimental results from both physical models with TVENT results, we showed that we have derived the proper similitude relations (governed by compressibility effects) for all sizes of ventilation systems. As a by-product of our studies, we determined the need for fan speed variation modeling in TVENT. This modification was made and resulted in a significant improvement in our comparisons of analytical and experimental results.

  15. Numerical simulation and experimental research on wake field of ships under off-design conditions

    NASA Astrophysics Data System (ADS)

    Guo, Chun-yu; Wu, Tie-cheng; Zhang, Qi; Gong, Jie

    2016-10-01

    Different operating conditions (e.g. design and off-design) may lead to a significant difference in the hydrodynamics performance of a ship, especially in the total resistance and wake field of ships. This work investigated the hydrodynamic performance of the well-known KRISO 3600 TEU Container Ship (KCS) under three different operating conditions by means of Particle Image Velocimetry (PIV) and Computational Fluid Dynamics (CFD). The comparison results show that the use of PIV to measure a ship's nominal wake field is an important method which has the advantages of being contactless and highly accurate. Acceptable agreements between the results obtained by the two different methods are achieved. Results indicate that the total resistances of the KCS model under two off-design conditions are 23.88% and 13.92% larger than that under the designed condition, respectively.

  16. Analytic and experimental evaluation of flowing air test conditions for selected metallics in a shuttle TPS application

    NASA Technical Reports Server (NTRS)

    Schaefer, J. W.; Tong, H.; Clark, K. J.; Suchsland, K. E.; Neuner, G. J.

    1975-01-01

    A detailed experimental and analytical evaluation was performed to define the response of TD nickel chromium alloy (20 percent chromium) and coated columbium (R512E on CB-752 and VH-109 on WC129Y) to shuttle orbiter reentry heating. Flight conditions important to the response of these thermal protection system (TPS) materials were calculated, and test conditions appropriate to simulation of these flight conditions in flowing air ground test facilities were defined. The response characteristics of these metallics were then evaluated for the flight and representative ground test conditions by analytical techniques employing appropriate thermochemical and thermal response computer codes and by experimental techniques employing an arc heater flowing air test facility and flat face stagnation point and wedge test models. These results were analyzed to define the ground test requirements to obtain valid TPS response characteristics for application to flight. For both material types in the range of conditions appropriate to the shuttle application, the surface thermochemical response resulted in a small rate of change of mass and a negligible energy contribution. The thermal response in terms of surface temperature was controlled by the net heat flux to the surface; this net flux was influenced significantly by the surface catalycity and surface emissivity. The surface catalycity must be accounted for in defining simulation test conditions so that proper heat flux levels to, and therefore surface temperatures of, the test samples are achieved.

  17. A new experimental facility for investigating the formation and properties of gas hydrates under simulated seafloor conditions

    SciTech Connect

    Phelps, Tommy J.; Peters, David J.; Marshall, Simon L.; West, Olivia R.; Liang, Liyuan; Blencoe, James G.; Alexiades, Vasilios; Jacobs, Gary K.; Naney, Michael T.; Heck, Jack L.

    2001-02-01

    A seafloor process simulator (SPS) has been developed for experimental investigations of the physical, geochemical, and microbiological processes affecting the formation and stability of methane and carbon dioxide hydrates at temperatures and pressures corresponding to ocean depths of 2 km. The SPS is a corrosion-resistant pressure vessel whose salient characteristics are: (i) an operating range suitable for study of methane and carbon dioxide hydrates; (ii) numerous access and observation ports, and (iii) a large (0.0722 m3) internal volume. Initial experiments have shown that the SPS can be used to produce large amounts of high-purity methane hydrate over a wide range of experimental conditions.

  18. 40 CFR 716.25 - Adequate file search.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Adequate file search. 716.25 Section 716.25 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT HEALTH AND SAFETY DATA REPORTING General Provisions § 716.25 Adequate file search. The scope of...

  19. 40 CFR 716.25 - Adequate file search.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Adequate file search. 716.25 Section 716.25 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT HEALTH AND SAFETY DATA REPORTING General Provisions § 716.25 Adequate file search. The scope of...

  20. "Something Adequate"? In Memoriam Seamus Heaney, Sister Quinlan, Nirbhaya

    ERIC Educational Resources Information Center

    Parker, Jan

    2014-01-01

    Seamus Heaney talked of poetry's responsibility to represent the "bloody miracle", the "terrible beauty" of atrocity; to create "something adequate". This article asks, what is adequate to the burning and eating of a nun and the murderous gang rape and evisceration of a medical student? It considers Njabulo Ndebele's…

  1. 40 CFR 716.25 - Adequate file search.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Adequate file search. 716.25 Section... ACT HEALTH AND SAFETY DATA REPORTING General Provisions § 716.25 Adequate file search. The scope of a person's responsibility to search records is limited to records in the location(s) where the...

  2. 40 CFR 51.354 - Adequate tools and resources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 2 2013-07-01 2013-07-01 false Adequate tools and resources. 51.354... Requirements § 51.354 Adequate tools and resources. (a) Administrative resources. The program shall maintain the administrative resources necessary to perform all of the program functions including...

  3. 40 CFR 51.354 - Adequate tools and resources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 2 2014-07-01 2014-07-01 false Adequate tools and resources. 51.354... Requirements § 51.354 Adequate tools and resources. (a) Administrative resources. The program shall maintain the administrative resources necessary to perform all of the program functions including...

  4. 40 CFR 51.354 - Adequate tools and resources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Adequate tools and resources. 51.354... Requirements § 51.354 Adequate tools and resources. (a) Administrative resources. The program shall maintain the administrative resources necessary to perform all of the program functions including...

  5. 40 CFR 51.354 - Adequate tools and resources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 2 2011-07-01 2011-07-01 false Adequate tools and resources. 51.354... Requirements § 51.354 Adequate tools and resources. (a) Administrative resources. The program shall maintain the administrative resources necessary to perform all of the program functions including...

  6. 40 CFR 51.354 - Adequate tools and resources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 2 2012-07-01 2012-07-01 false Adequate tools and resources. 51.354... Requirements § 51.354 Adequate tools and resources. (a) Administrative resources. The program shall maintain the administrative resources necessary to perform all of the program functions including...

  7. 9 CFR 305.3 - Sanitation and adequate facilities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Sanitation and adequate facilities. 305.3 Section 305.3 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... OF VIOLATION § 305.3 Sanitation and adequate facilities. Inspection shall not be inaugurated if...

  8. 9 CFR 305.3 - Sanitation and adequate facilities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Sanitation and adequate facilities. 305.3 Section 305.3 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... OF VIOLATION § 305.3 Sanitation and adequate facilities. Inspection shall not be inaugurated if...

  9. 9 CFR 305.3 - Sanitation and adequate facilities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Sanitation and adequate facilities. 305.3 Section 305.3 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... OF VIOLATION § 305.3 Sanitation and adequate facilities. Inspection shall not be inaugurated if...

  10. 9 CFR 305.3 - Sanitation and adequate facilities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Sanitation and adequate facilities. 305.3 Section 305.3 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... OF VIOLATION § 305.3 Sanitation and adequate facilities. Inspection shall not be inaugurated if...

  11. 9 CFR 305.3 - Sanitation and adequate facilities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Sanitation and adequate facilities. 305.3 Section 305.3 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... OF VIOLATION § 305.3 Sanitation and adequate facilities. Inspection shall not be inaugurated if...

  12. 21 CFR 201.5 - Drugs; adequate directions for use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 4 2011-04-01 2011-04-01 false Drugs; adequate directions for use. 201.5 Section 201.5 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL LABELING General Labeling Provisions § 201.5 Drugs; adequate directions for use....

  13. An experimental and theoretical study of the ice accretion process during artificial and natural icing conditions

    NASA Technical Reports Server (NTRS)

    Kirby, Mark S.; Hansman, R. John

    1988-01-01

    Real-time measurements of ice growth during artificial and natural icing conditions were conducted using an ultrasonic pulse-echo technique. This technique allows ice thickness to be measured with an accuracy of + or - 0.5 mm; in addition, the ultrasonic signal characteristics may be used to detect the presence of liquid on the ice surface and hence discern wet and dry ice growth behavior. Ice growth was measured on the stagnation line of a cylinder exposed to artificial icing conditions in the NASA Lewis Icing Research Tunnel (IRT), and similarly for a cylinder exposed in flight to natural icing conditions. Ice thickness was observed to increase approximately linearly with exposure time during the initial icing period. The ice accretion rate was found to vary with cloud temperature during wet ice growth, and liquid runback from the stagnation region was inferred. A steady-state energy balance model for the icing surface was used to compare heat transfer characteristics for IRT and natural icing conditions. Ultrasonic measurements of wet and dry ice growth observed in the IRT and in flight were compared with icing regimes predicted by a series of heat transfer coefficients. The heat transfer magnitude was generally inferred to be higher for the IRT than for the natural icing conditions encountered in flight. An apparent variation in the heat transfer magnitude was also observed for flights conducted through different natural icing-cloud formations.

  14. [The concentration of viruses in water using the tangential flow ultrafiltration. Recovery effectiveness in experimental conditions].

    PubMed

    Bigliardi, L; Cesari, C; Zoni, R; Sansebastiano, G E

    2004-01-01

    Poliovirus 1 concentration tests were carried out in artificially contaminated water by tangential flow ultrafiltration with Polisulfone filters 100000 MWCO. The tests were performed in 1 and in 20 liters of waters. The filters were conditioned and eluted respectively with Beef extract 3% and with glicina 1% at pH 7 and pH 9. The recovery mean using Beef extract resulted properly good, about the 83% and comparable to percentages we obtained in previous works with filters in cellulose nitrate and Virosorb filters. The viral recovery was low using the glicina for conditioning and eluting the filters.

  15. Experimental Studies of Hydrogenation and Other Reactions on Surfaces Under Astrophysically Relevant Conditions

    NASA Technical Reports Server (NTRS)

    Vidali, Gianfranco

    1998-01-01

    The goal of our project is to study hydrogen recombination reactions on solid surfaces under conditions that are relevant in astrophysics. Laboratory experiments were conducted using low-flux, cold atomic H and D beams impinging on a sample kept under ultra high vacuum conditions. Realistic analogues of interstellar dust grains were used. Our results show that current models for hydrogen recombination reactions have to be modified to take into account the role of activated diffusion of H on surfaces even at low temperature.

  16. The effect of formulations and experimental conditions on in vitro human skin permeation-Data from updated EDETOX database.

    PubMed

    Samaras, Eleftherios G; Riviere, Jim E; Ghafourian, Taravat

    2012-09-15

    In vitro methods are commonly used in order to estimate the extent of systemic absorption of chemicals through skin. Due to the wide variability of experimental procedures, types of skin and data analytical methods, the resulting permeation measures varies significantly between laboratories and individuals. Inter-laboratory and inter-individual variations with the in vitro measures of skin permeation lead to unreliable extrapolations to in vivo situations. This investigation aimed at a comprehensive assessment of the available data and development of validated models for in vitro skin flux of chemicals under various experimental and vehicle conditions. Following an exhaustive literature review, the human skin flux data were collated and combined with those from EDETOX database resulting in a dataset of a total of 536 flux reports. Quantitative structure-activity relationship techniques combined with data mining tools were used to develop models incorporating the effects of permeant molecular structure, properties of the vehicle, and the experimental conditions including the membrane thickness, finite/infinite exposure, skin pre-hydration and occlusion. The work resulted in statistically valid models for estimation of the skin flux from varying experimental conditions, including relevant real-world mixture exposure scenarios. The models indicated that the most prominent factors influencing flux values were the donor concentration, lipophilicity, size and polarity of the penetrant, and the melting and boiling points of the vehicle, with skin occlusion playing significant role in a non-linear way. The models will aid assessment of the utility of dermal absorption data collected under different conditions with broad implications on transdermal delivery research.

  17. Spontaneous Chronic Pain After Experimental Thoracotomy Revealed by Conditioned Place Preference: Morphine Differentiates Tactile Evoked Pain From Spontaneous Pain.

    PubMed

    Hung, Ching-Hsia; Wang, Jeffrey Chi-Fei; Strichartz, Gary R

    2015-09-01

    Chronic pain after surgery limits social activity, interferes with work, and causes emotional suffering. A major component of such pain is reported as resting or spontaneous pain with no apparent external stimulus. Although experimental animal models can simulate the stimulus-evoked chronic pain that occurs after surgery, there have been no studies of spontaneous chronic pain in such models. Here the conditioned place preference (CPP) paradigm was used to reveal resting pain after experimental thoracotomy. Male Sprague Dawley rats received a thoracotomy with 1-hour rib retraction, resulting in evoked tactile hypersensitivity, previously shown to last for at least 9 weeks. Intraperitoneal injections of morphine (2.5 mg/kg) or gabapentin (40 mg/kg) gave equivalent 2- to 3-hour-long relief of tactile hypersensitivity when tested 12 to 14 days postoperatively. In separate experiments, single trial CPP was conducted 1 week before thoracotomy and then 12 days (gabapentin) or 14 days (morphine) after surgery, followed the next day by 1 conditioning session with morphine or gabapentin, both versus saline. The gabapentin-conditioned but not the morphine-conditioned rats showed a significant preference for the analgesia-paired chamber, despite the equivalent effect of the 2 agents in relieving tactile allodynia. These results show that experimental thoracotomy in rats causes spontaneous pain and that some analgesics, such as morphine, that reduce evoked pain do not also relieve resting pain, suggesting that pathophysiological mechanisms differ between these 2 aspects of long-term postoperative pain. Perspective: Spontaneous pain, a hallmark of chronic postoperative pain, is demonstrated here in a rat model of experimental postthoracotomy pain, further validating the use of this model for the development of analgesics to treat such symptoms. Although stimulus-evoked pain was sensitive to systemic morphine, spontaneous pain was not, suggesting different mechanistic

  18. Experimental Investigation of Muon-catalyzed dt Fusion in Wide Ranges of D/T Mixture Conditions

    SciTech Connect

    Bom, V.R.; Eijk, C.W.E. van; Demin, A.M.; Golubkov, A.N.; Grishechkin, S.K.; Klevtsov, V.G.; Kuryakin, A.V.; Musyaev, R.K.; Perevozchikov, V.V.; Vinogradov, Yu.I.; Yukhimchuk, A.A.; Zlatoustovskii, S.V.; Demin, D.L.; Filchenkov, V.V.; Grafov, N.N.; Gritsaj, K.I.; Konin, A.D.; Medved', S.V.; Rudenko, A.I.; Yukhimchuk, S.A.

    2005-04-01

    A vast program of the experimental investigation of muon-catalyzed dt fusion was performed on the Joint Institute for Nuclear Research phasotron. Parameters of the dt cycle were obtained in a wide range of the D/T mixture conditions: temperatures of 20-800 K, densities of 0.2-1.2 of the liquid hydrogen density (LHD), and tritium concentrations of 15-86%. In this paper, the results obtained are summarized.

  19. Experimental investigation of convective drying kinetics of kiwi under different conditions

    NASA Astrophysics Data System (ADS)

    Darıcı, Selçuk; Şen, Soner

    2015-08-01

    The effects of air temperature, velocity and humidity on drying characteristics of kiwi are experimentally investigated for the temperatures in the range of 50-80 °C, of the velocities 0.5-2.0 m/s, of the relative humidity values of 5-20 % and for two slice thicknesses. It is observed that there is a very close agreement between the model of Midilli et al. (Dry Technol 20:1503-1513, 2002) and the present study with coefficients of correlation R2 of 0.9949-0.9996.

  20. Experimental Study on the Control of the Supersonic Axisymmetric Intake under the Acceleration/Deceleration Conditions

    NASA Astrophysics Data System (ADS)

    Kojima, Takayuki; Sato, Tetsuya; Tanatsugu, Nobuhiro; Enomoto, Yoshinari

    A control system of variable geometry mixed compression axisymmetric intake is experimentally studied at ONERA S3 supersonic wind tunnel. The acceleration/deceleration of the space plane is simulated by changing the free stream velocity. The intake is successfully controlled with 90% of the maximum total pressure recovery and mass capture ratio. In this experiment, two subjects about control of axisymmetric intake are also cleared. First, the effect of the trapping of the terminal shock by bleed holes causes the disturbances in the terminal shock control system. Second, a special compression form change operation is necessary when the intake compression form change from all external compression to mixed compression.

  1. Optimal experimental design for improving the estimation of growth parameters of Lactobacillus viridescens from data under non-isothermal conditions.

    PubMed

    Longhi, Daniel Angelo; Martins, Wiaslan Figueiredo; da Silva, Nathália Buss; Carciofi, Bruno Augusto Mattar; de Aragão, Gláucia Maria Falcão; Laurindo, João Borges

    2017-01-02

    presented smaller confidence intervals and best statistical indexes than those from TSM approach. Besides, less experimental data and time were needed to estimate the model parameters with OED than TSM. Furthermore, the OED model parameters were validated with non-isothermal experimental data with great accuracy. In this way, OED approach is feasible and is a very useful tool to improve the prediction of microbial growth under non-isothermal condition.

  2. An Experimental Concept to Measure Opacities Under Solar-relevant Conditions

    NASA Astrophysics Data System (ADS)

    Keiter, Paul; Mussack, K.; Klein, S.

    2013-06-01

    Recent solar abundance models (Asplund 2009) use a significantly lower abundance for C, N, O compared to models used roughly a decade ago. Although the models used now are much more sophisticated than before, a discrepancy still exists between the abundances in the models and the abundances determined by helioseismic inferences. Agreement can be obtained by ad hoc adjustments to the opacity of high-Z (Z > 2) elements ranging from a few percent in the solar interior to as much as 30% just below the convection zone (CZ). Although many of the opacity models are thought to agree within a few percent, a recent element-by-element study (Blancard 2012) indicates a larger disagreement between models for certain elements. Experimental opacity measurements for these elements in the regimes of interest will provide valuable information to help resolve these discrepancies. We will present an experimental platform designed to measure the opacity of C, N, and O and discuss the achievable parameter regime. We will also briefly discuss how this platform can be extended to include other high-Z elements.

  3. An experimental concept to measure opacities under solar-relevant conditions

    NASA Astrophysics Data System (ADS)

    Keiter, Paul A.; Mussack, Katie; Klein, Sallee R.

    2013-06-01

    Recent solar abundance models (Asplund 2009) use a significantly lower abundance for C, N, O compared to models used roughly a decade ago. Although the models used now are much more sophisticated than before, a discrepancy still exists between the abundances in the models and the abundances determined by helioseismic measurements. Agreement can be obtained by ad hoc adjustments to the opacity of high-Z (Z > 2) elements ranging from a few percent in the solar interior to as much as 30 just below the convection zone (CZ). Although many of the opacity models are thought to agree within a few percent, a recent element-by-element study (Blancard 2012) indicates a larger disagreement between models for certain elements. Experimental opacity measurements for these elements in the regimes of interest will provide valuable information to help resolve these discrepancies. We will present an experimental platform designed to measure the opacity of C, N, and O and discuss the achievable parameter regime. We will also briefly discuss how this platform can be extended to include other high-Z elements.

  4. Simulation of VSPT Experimental Cascade Under High and Low Free-Stream Turbulence Conditions

    NASA Technical Reports Server (NTRS)

    Ameri, Ali A.; Giel, Paul W.; Flegel, Ashlie

    2014-01-01

    Variable-Speed Power Turbines (VSPT) for rotorcraft applications operate in conditions of low Reynolds number and a wide range in incidence resulting from rotational speed variation. A comprehensive data set obtained in a linear cascade which includes the effects of Reynolds number, free-stream turbulence and incidence is now available and this paper concerns itself with the post-diction of boundary layer transitionseparation, blade pressure loading and total pressure loss pertaining to the conditions set for measurements in that data set. The distinction between the state of the measured data presented here and the earlier publications is the addition of high free-stream turbulence intensity. We will, for the purposes of the numerical post-diction, present some of the higher free stream turbulence data in this paper but defer a comprehensive presentation and treatment of the measured data will be done elsewhere.

  5. Experimental models for guided bone regeneration in healthy and medically compromised conditions.

    PubMed

    Donos, Nikolaos; Dereka, Xanthippi; Mardas, Nikos

    2015-06-01

    The increased use of dental implants and related bone-augmentation procedures creates a need for reliable proof-of-principle preclinical models for evaluating different bone-regenerative techniques. The simulation of clinical scenarios by such models is of importance when the experiments are designed in order for the outcomes to provide basic points of clinical relevance. At the same time, the increased proportion of the population with different chronic diseases of ageing necessitates the need to reproduce these conditions in the same proof-of-principle preclinical models to allow evaluation of the effect of the relevant chronic disease on the bone-healing process. This review presents a number of 'proof-of-principle' preclinical models in health and in chronic systemic conditions in which the guided bone regeneration principle was evaluated.

  6. Mineral-catalyzed dehydrogenation of C6 cyclic hydrocarbons: results from experimental studies under hydrothermal conditions

    NASA Astrophysics Data System (ADS)

    Venturi, S.; Tassi, F.; Gould, I.; Shock, E.; Lorance, E. D.; Bockisch, C.; Fecteau, K.

    2015-12-01

    Volatile organic compounds (VOCs) are ubiquitously present in volcanic and hydrothermal gases. Their relative abundances have been demonstrated to be sensitive to physical and chemical parameters, suggesting VOCs as potential tools for evaluating deep reservoir conditions. Nevertheless, reaction pathways for VOC production at hydrothermal conditions are still poorly understood. Reversible catalytic reforming may be responsible for the high abundance of benzene observed in hydrothermal gases relative to saturated hydrocarbons. The dehydrogenation of n-hexane to benzene could proceed with C6 cyclic hydrocarbons as intermediates, as suggested by the relative enrichment in cyclic hydrocarbons observed in gases originating at T <150 °C. In this study, laboratory experiments were carried out to investigate the production of benzene from cyclic hydrocarbons at 300°C and 85 bar. At these conditions in pure water, negligible benzene is produced from cyclohexane after 10 days. The presence of a mineral phase, especially sphalerite, favored the formation of both benzene and cyclohexene. The efficiency of dehydroaromatization reaction increased at increasing mineral/cyclohexane ratio, pointing to a surface catalyzed reaction. The catalytic action of sphalerite on the C-H bonds was confirmed by the large abundance of deuterated cyclohexane resulted in D2O experiments. The same experiment carried out using cyclohexene in pure water mainly produced methyl-cyclopentenes (via isomerization) and cyclohexanol (via oxygenation). In presence of sphalerite, the production of significant amounts of benzene confirmed the critical role of this mineral for the aromatization of cyclic compounds under hydrothermal conditions. Contrarily, products from cyclohexene solution phase oxidation using Cu(II) mainly consisted of oxygenated VOCs.

  7. Theoretical and experimental investigations of thermal conditions of household biogas plant

    NASA Astrophysics Data System (ADS)

    Zhelykh, Vasil; Furdas, Yura; Dzeryn, Oleksandra

    2016-06-01

    The construction of domestic continuous bioreactor is proposed. The modeling of thermal modes of household biogas plant using graph theory was done. The correction factor taking into account with the influence of variables on its value was determined. The system of balance equations for the desired thermal conditions in the bioreactor was presented. The graphical and analytical capabilities were represented that can be applied in the design of domestic biogas plants of organic waste recycling.

  8. Experimental study of the pressure fluctuations in a pump turbine at large partial flow conditions

    NASA Astrophysics Data System (ADS)

    Ran, Hongjuan; Luo, Xianwu; Zhu, Lei; Zhang, Yao; Wang, Xin; Xu, Hongyuan

    2012-11-01

    Frequent shifts of output and operating mode require a pump turbine with excellent stability. Current researches show that large partial flow conditions in pump mode experience positive-slope phenomena with a large head drop. The pressure fluctuation at the positive slope is crucial to the pump turbine unit safety. The operating instabilities at large partial flow conditions for a pump turbine are analyzed. The hydraulic performance of a model pump turbine is tested with the pressure fluctuations measured at unstable operating points near a positive slope in the performance curve. The hydraulic performance tests show that there are two separated positive-slope regions for the pump turbine, with the flow discharge for the first positive slope from 0.85 to 0.91 times that at the maximum efficiency point. The amplitudes of the pressure fluctuations at these unstable large partial flow conditions near the first positive slope are much larger than those at stable operating condtions. A dominant frequency is measured at 0.2 times the impeller rotational frequency in the flow passage near the impeller exit, which is believed to be induced by the rotating stall in the flow passage of the wicket gates. The test results also show hysteresis with pressure fluctuations when the pump turbine is operated near the first positive slope. The hysteresis creates different pressure fluctuations for those operation points even though their flow rates and heads are similar respectively. The pressure fluctuation characteristics at large partial flow conditions obtained by the present study will be helpful for the safe operation of pumped storage units.

  9. Boundary condition identification for a grid model by experimental and numerical dynamic analysis

    NASA Astrophysics Data System (ADS)

    Mao, Qiang; Devitis, John; Mazzotti, Matteo; Bartoli, Ivan; Moon, Franklin; Sjoblom, Kurt; Aktan, Emin

    2015-04-01

    There is a growing need to characterize unknown foundations and assess substructures in existing bridges. It is becoming an important issue for the serviceability and safety of bridges as well as for the possibility of partial reuse of existing infrastructures. Within this broader contest, this paper investigates the possibility of identifying, locating and quantifying changes of boundary conditions, by leveraging a simply supported grid structure with a composite deck. Multi-reference impact tests are operated for the grid model and modification of one supporting bearing is done by replacing a steel cylindrical roller with a roller of compliant material. Impact based modal analysis provide global modal parameters such as damped natural frequencies, mode shapes and flexibility matrix that are used as indicators of boundary condition changes. An updating process combining a hybrid optimization algorithm and the finite element software suit ABAQUS is presented in this paper. The updated ABAQUS model of the grid that simulates the supporting bearing with springs is used to detect and quantify the change of the boundary conditions.

  10. Effect of Clonal Selection on Daphnia Tolerance to Dark Experimental Conditions

    PubMed Central

    Gitzen, Robert A.; Williamson, Craig E.; González, Maria J.

    2016-01-01

    Recent studies have demonstrated substantial effects of environmental stress that vary among clones. Exposure to ultraviolet radiation (UV) is an important abiotic stressor that is highly variable in aquatic ecosystems due to diel and seasonal variations in incident sunlight as well as to differences in the UV transparency of water among water bodies, the depth distribution of organisms, and the ability of organisms to detect and respond to UV. In contrast to the convention that all UV is damaging, evidence is accumulating for the beneficial effects of exposure to low levels of UV radiation. Whereas UV has been frequently observed as the primary light-related stressor, herein we present evidence that dark conditions may be similarly “stressful” (reduction of overall fitness), and stress responses vary among clones of the freshwater crustacean Daphnia parvula. We have identified a significant relationship between survivorship and reduced fecundity of clones maintained in dark conditions, but no correlation between tolerance of the clones to dark and UV radiation. Low tolerance to dark conditions can have negative effects not only on accumulated stresses in organisms (e.g. the repair of UV-induced damage in organisms with photolyase), but potentially on the overall physiology and fitness of organisms. Our results support recent evidence of the beneficial effects of low-level UV exposure for some organisms. PMID:27434210

  11. Observational fear conditioning in the acquisition and extinction of attentional bias for threat: an experimental evaluation.

    PubMed

    Kelly, Megan M; Forsyth, John P

    2007-05-01

    Anxious persons show automatic and strategic attentional biases for threatening information. Yet, the mechanisms and processes that underlie such biases remain unclear. The central aim of the present study was to elucidate the relation between observational threat learning and the acquisition and extinction of biased threat processing by integrating emotional Stroop color naming tasks within an observational differential fear conditioning procedure. Forty-three healthy female participants underwent several consecutive observational fear conditioning phases. During acquisition, participants watched a confederate displaying mock panic attacks (UCS) paired with a verbal stimulus (CS+), but not with a second nonreinforced verbal stimulus (CS-). As expected, participants showed greater magnitude electrodermal and verbal-evaluative (e.g., distress, fear) conditioned responses to the CS+ over the CS- word. Participants also demonstrated slower color-naming latencies to CS+ compared to the CS- word following acquisition and showed attenuation of this preferential processing bias for threat following extinction. Findings are discussed broadly in the context of the interplay between fear learning and processing biases for threat as observed in persons suffering from anxiety disorders.

  12. Transport of spin qubits with donor chains under realistic experimental conditions

    SciTech Connect

    Mohiyaddin, Fahd A.; Kalra, Rachpon; Laucht, Arne; Rahman, Rajib; Klimeck, Gerhard; Morello, Andrea

    2016-07-25

    The ability to transport quantum information across some distance can facilitate the design and operation of a quantum processor. One-dimensional spin chains provide a compact platform to realize scalable spin transport for a solid-state quantum computer. Here, we model odd-sized donor chains in silicon under a range of experimental nonidealities, including variability of donor position within the chain. We show that the tolerance against donor placement inaccuracies is greatly improved by operating the spin chain in a mode where the electrons are confined at the Si-SiO2 interface. We then estimate the required time scales and exchange couplings, and the level of noise that can be tolerated to achieve high-fidelity transport. As a result, we also propose a protocol to calibrate and initialize the chain, thereby providing a complete guideline for realizing a functional donor chain and utilizing it for spin transport.

  13. A frost formation model and its validation under various experimental conditions

    NASA Technical Reports Server (NTRS)

    Dietenberger, M. A.

    1982-01-01

    A numerical model that was used to calculate the frost properties for all regimes of frost growth is described. In the first regime of frost growth, the initial frost density and thickness was modeled from the theories of crystal growth. The 'frost point' temperature was modeled as a linear interpolation between the dew point temperature and the fog point temperature, based upon the nucleating capability of the particular condensing surfaces. For a second regime of frost growth, the diffusion model was adopted with the following enhancements: the generalized correlation of the water frost thermal conductivity was applied to practically all water frost layers being careful to ensure that the calculated heat and mass transfer coefficients agreed with experimental measurements of the same coefficients.

  14. Transport of spin qubits with donor chains under realistic experimental conditions

    DOE PAGES

    Mohiyaddin, Fahd A.; Kalra, Rachpon; Laucht, Arne; ...

    2016-07-25

    The ability to transport quantum information across some distance can facilitate the design and operation of a quantum processor. One-dimensional spin chains provide a compact platform to realize scalable spin transport for a solid-state quantum computer. Here, we model odd-sized donor chains in silicon under a range of experimental nonidealities, including variability of donor position within the chain. We show that the tolerance against donor placement inaccuracies is greatly improved by operating the spin chain in a mode where the electrons are confined at the Si-SiO2 interface. We then estimate the required time scales and exchange couplings, and the levelmore » of noise that can be tolerated to achieve high-fidelity transport. As a result, we also propose a protocol to calibrate and initialize the chain, thereby providing a complete guideline for realizing a functional donor chain and utilizing it for spin transport.« less

  15. Experimental conditions can obscure the second high-affinity site in LeuT.

    PubMed

    Quick, Matthias; Shi, Lei; Zehnpfennig, Britta; Weinstein, Harel; Javitch, Jonathan A

    2012-01-15

    Neurotransmitter:Na(+) symporters (NSSs), the targets of antidepressants and psychostimulants, recapture neurotransmitters from the synapse in a Na(+)-dependent symport mechanism. The crystal structure of the NSS homolog LeuT from Aquifex aeolicus revealed one leucine substrate in an occluded, centrally located (S1) binding site next to two Na(+) ions. Computational studies combined with binding and flux experiments identified a second substrate (S2) site and a molecular mechanism of Na(+)-substrate symport that depends upon the allosteric interaction of substrate molecules in the two high-affinity sites. Here we show that the S2 site, which has not yet been identified by crystallographic approaches, can be blocked during preparation of detergent-solubilized LeuT, thereby obscuring its crucial role in Na(+)-coupled symport. This finding points to the need for caution in selecting experimental environments in which the properties and mechanistic features of membrane proteins can be delineated.

  16. Identification and Evaluation of Reference Genes for Accurate Transcription Normalization in Safflower under Different Experimental Conditions

    PubMed Central

    Li, Dandan; Hu, Bo; Wang, Qing; Liu, Hongchang; Pan, Feng; Wu, Wei

    2015-01-01

    Safflower (Carthamus tinctorius L.) has received a significant amount of attention as a medicinal plant and oilseed crop. Gene expression studies provide a theoretical molecular biology foundation for improving new traits and developing new cultivars. Real-time quantitative PCR (RT-qPCR) has become a crucial approach for gene expression analysis. In addition, appropriate reference genes (RGs) are essential for accurate and rapid relative quantification analysis of gene expression. In this study, fifteen candidate RGs involved in multiple metabolic pathways of plants were finally selected and validated under different experimental treatments, at different seed development stages and in different cultivars and tissues for real-time PCR experiments. These genes were ABCS, 60SRPL10, RANBP1, UBCL, MFC, UBCE2, EIF5A, COA, EF1-β, EF1, GAPDH, ATPS, MBF1, GTPB and GST. The suitability evaluation was executed by the geNorm and NormFinder programs. Overall, EF1, UBCE2, EIF5A, ATPS and 60SRPL10 were the most stable genes, and MBF1, as well as MFC, were the most unstable genes by geNorm and NormFinder software in all experimental samples. To verify the validation of RGs selected by the two programs, the expression analysis of 7 CtFAD2 genes in safflower seeds at different developmental stages under cold stress was executed using different RGs in RT-qPCR experiments for normalization. The results showed similar expression patterns when the most stable RGs selected by geNorm or NormFinder software were used. However, the differences were detected using the most unstable reference genes. The most stable combination of genes selected in this study will help to achieve more accurate and reliable results in a wide variety of samples in safflower. PMID:26457898

  17. Experimental investigation of static ice refrigeration air conditioning system driven by distributed photovoltaic energy system

    NASA Astrophysics Data System (ADS)

    Xu, Y. F.; Li, M.; Luo, X.; Wang, Y. F.; Yu, Q. F.; Hassanien, R. H. E.

    2016-08-01

    The static ice refrigeration air conditioning system (SIRACS) driven by distributed photovoltaic energy system (DPES) was proposed and the test experiment have been investigated in this paper. Results revealed that system energy utilization efficiency is low because energy losses were high in ice making process of ice slide maker. So the immersed evaporator and co-integrated exchanger were suggested in system structure optimization analysis and the system COP was improved nearly 40%. At the same time, we have researched that ice thickness and ice super-cooled temperature changed along with time and the relationship between system COP and ice thickness was obtained.

  18. Region 9: Arizona Adequate Letter (10/14/2003)

    EPA Pesticide Factsheets

    This is a letter from Jack P. Broadben,. Director, to Nancy Wrona and Dennis Smith informing them that Maricopa County's motor vehicle emissions budgets in the 2003 MAGCO Maintenance Plan are adequate for transportation conformity purposes.

  19. Region 6: Texas Adequate Letter (4/16/2010)

    EPA Pesticide Factsheets

    This letter from EPA to Texas Commission on Environmental Quality determined 2021 motor vehicle emission budgets for nitrogen oxides (NOx) and volatile organic compounds (VOCs) for Beaumont/Port Arthur area adequate for transportation conformity purposes

  20. Region 2: New Jersey Adequate Letter (5/23/2002)

    EPA Pesticide Factsheets

    This April 22, 2002 letter from EPA to the New Jersey Department of Environmental Protection determined 2007 and 2014 Carbon Monoxide (CO) Mobile Source Emissions Budgets adequate for transportation conformity purposes and will be announced in the Federal

  1. Region 8: Colorado Adequate Letter (10/29/2001)

    EPA Pesticide Factsheets

    This letter from EPA to Colorado Department of Public Health and Environment determined Denvers' particulate matter (PM10) maintenance plan for Motor Vehicle Emissions Budgets adequate for transportation conformity purposes.

  2. Region 1: New Hampshire Adequate Letter (8/12/2008)

    EPA Pesticide Factsheets

    This July 9, 2008 letter from EPA to the New Hampshire Department of Environmental Services, determined the 2009 Motor Vehicle Emissions Budgets (MVEBs) are adequate for transportation conformity purposes and will be announced in the Federal Register (FR).

  3. Region 8: Colorado Adequate Letter (1/20/2004)

    EPA Pesticide Factsheets

    This letter from EPA to Colorado Department of Public Health and Environment determined Greeleys' Carbon Monoxide (CO) maintenance plan for Motor Vehicle Emissions Budgets adequate for transportation conformity purposes and will be announced in the FR.

  4. Region 8: Utah Adequate Letter (6/10/2005)

    EPA Pesticide Factsheets

    This letter from EPA to Utah Department of Environmental Quality determined Salt Lake Citys' and Ogdens' Carbon Monoxide (CO) maintenance plan for Motor Vehicle Emissions Budgets adequate for transportation conformity purposes.

  5. 15 CFR 970.404 - Adequate exploration plan.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ENVIRONMENTAL DATA SERVICE DEEP SEABED MINING REGULATIONS FOR EXPLORATION LICENSES Certification of Applications § 970.404 Adequate exploration plan. Before he may certify an application, the Administrator must...

  6. 15 CFR 970.404 - Adequate exploration plan.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ENVIRONMENTAL DATA SERVICE DEEP SEABED MINING REGULATIONS FOR EXPLORATION LICENSES Certification of Applications § 970.404 Adequate exploration plan. Before he may certify an application, the Administrator must...

  7. 15 CFR 970.404 - Adequate exploration plan.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ENVIRONMENTAL DATA SERVICE DEEP SEABED MINING REGULATIONS FOR EXPLORATION LICENSES Certification of Applications § 970.404 Adequate exploration plan. Before he may certify an application, the Administrator must...

  8. 15 CFR 970.404 - Adequate exploration plan.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ENVIRONMENTAL DATA SERVICE DEEP SEABED MINING REGULATIONS FOR EXPLORATION LICENSES Certification of Applications § 970.404 Adequate exploration plan. Before he may certify an application, the Administrator must...

  9. 15 CFR 970.404 - Adequate exploration plan.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ENVIRONMENTAL DATA SERVICE DEEP SEABED MINING REGULATIONS FOR EXPLORATION LICENSES Certification of Applications § 970.404 Adequate exploration plan. Before he may certify an application, the Administrator must...

  10. Region 6: New Mexico Adequate Letter (8/21/2003)

    EPA Pesticide Factsheets

    This is a letter from Carl Edlund, Director, to Alfredo Santistevan regarding MVEB's contained in the latest revision to the Albuquerque Carbon Monoxide State Implementation Plan (SIP) are adequate for transportation conformity purposes.

  11. 10 CFR 1304.114 - Responsibility for maintaining adequate safeguards.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... contained in a system of records are adequately trained to protect the security and privacy of such records..., by degaussing or by overwriting with the appropriate security software, in accordance...

  12. 4 CFR 200.14 - Responsibility for maintaining adequate safeguards.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... require access to and use of records contained in a system of records are adequately trained to protect... with the appropriate security software, in accordance with regulations of the Archivist of the...

  13. 10 CFR 1304.114 - Responsibility for maintaining adequate safeguards.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... contained in a system of records are adequately trained to protect the security and privacy of such records..., by degaussing or by overwriting with the appropriate security software, in accordance...

  14. 4 CFR 200.14 - Responsibility for maintaining adequate safeguards.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... require access to and use of records contained in a system of records are adequately trained to protect... with the appropriate security software, in accordance with regulations of the Archivist of the...

  15. 10 CFR 1304.114 - Responsibility for maintaining adequate safeguards.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... contained in a system of records are adequately trained to protect the security and privacy of such records..., by degaussing or by overwriting with the appropriate security software, in accordance...

  16. 10 CFR 1304.114 - Responsibility for maintaining adequate safeguards.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... contained in a system of records are adequately trained to protect the security and privacy of such records..., by degaussing or by overwriting with the appropriate security software, in accordance...

  17. 4 CFR 200.14 - Responsibility for maintaining adequate safeguards.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... require access to and use of records contained in a system of records are adequately trained to protect... with the appropriate security software, in accordance with regulations of the Archivist of the...

  18. Region 9: Nevada Adequate Letter (3/30/2006)

    EPA Pesticide Factsheets

    This is a letter from Deborah Jordan, Director, to Leo M. Drozdoff regarding Nevada's motor vehicle emissions budgets in the 2005 Truckee Meadows CO Redesignation Request and Maintenance Plan are adequate for transportation conformity decisions.

  19. Experimental design approach in recombinant protein expression: determining medium composition and induction conditions for expression of pneumolysin from Streptococcus pneumoniae in Escherichia coli and preliminary purification process

    PubMed Central

    2014-01-01

    Background Streptococcus pneumoniae (S. pneumoniae) causes several serious diseases including pneumonia, septicemia and meningitis. The World Health Organization estimates that streptococcal pneumonia is the cause of approximately 1.9 million deaths of children under five years of age each year. The large number of serotypes underlying the disease spectrum, which would be reflected in the high production cost of a commercial vaccine effective to protect against all of them and the higher level of amino acid sequence conservation as compared to polysaccharide structure, has prompted us to attempt to use conserved proteins for the development of a simpler vaccine. One of the most prominent proteins is pneumolysin (Ply), present in almost all the serotypes known at the moment, which shows an effective protection against S. pneumoniae infections. Results We have cloned the pneumolysin gene from S. pneumoniae serotype 14 and studied the effects of eight variables related to medium composition and induction conditions on the soluble expression of rPly in Escherichia coli (E. coli) and a 28-4 factorial design was applied. Statistical analysis was carried out to compare the conditions used to evaluate the expression of soluble pneumolysin; rPly activity was evaluated by hemolytic activity assay and served as the main response to evaluate the proper protein expression and folding. The optimized conditions, validated by the use of triplicates, include growth until an absorbance of 0.8 (measured at 600 nm) with 0.1 mM IPTG during 4 h at 25°C in a 5 g/L yeast extract, 5 g/L tryptone, 10 g/L NaCl, 1 g/L glucose medium, with addition of 30 μg/mL kanamycin. Conclusions This experimental design methodology allowed the development of an adequate process condition to attain high levels (250 mg/L) of soluble expression of functional rPly in E. coli, which should contribute to reduce operational costs. It was possible to recover the protein in its active form with 75

  20. Experimental characterization of an industrial pulverized coal-fired furnace under deep staging conditions

    SciTech Connect

    Costa, M.; Azevedo, J.L.T.

    2007-07-01

    Measurements have been performed in a 300 MWe, front-wall-fired, pulverized-coal, utility boiler. This boiler was retrofitted with boosted over fire air injectors that allowed the operation of the furnace under deeper staging conditions. New data are reported for local mean gas species concentration of O{sub 2}, CO, CO{sub 2}, NOx, gas temperatures and char burnout measured at several ports in the boiler including those in the main combustion and staged air regions. Comparisons of the present data with our previous measurements in this boiler, prior to the retrofitting with the new over fire system, show lower O{sub 2} and higher CO concentrations for the new situation as a consequence of the lower stoichiometry in the main combustion zone associated with the present boiler operating condition. Consistently, the measured mean NOx concentrations in the main combustion zone are now lower than those obtained previously, yielding emissions below 500 mg/Nm{sup 3}at 6% O{sub 2}. Finally, the measured values of particle burnout at the furnace exit are acceptable being those measured in the main combustion zone comparable with those obtained with the conventional over fire system.

  1. Theoretical and experimental study of the formation conditions of stepped leaders in negative flashes

    SciTech Connect

    Xie, Shijun; Zeng, Rong; Zhuang, Chijie; Li, Jianming

    2015-08-15

    Natural lightning flashes are stochastic and uncontrollable, and thus, it is difficult to observe the formation process of a downward negative stepped leader (NSL) directly and in detail. This situation has led to some dispute over the actual NSL formation mechanism, and thus has hindered improvements in the lightning shielding analysis model. In this paper, on the basis of controllable long air gap discharge experiments, the formation conditions required for NSLs in negative flashes have been studied. First, a series of simulation experiments on varying scales were designed and carried out. The NSL formation processes were observed, and several of the characteristic process parameters, including the scale, the propagation velocity, and the dark period, were obtained. By comparing the acquired formation processes and the characteristic parameters with those in natural lightning flashes, the similarity between the NSLs in the simulation experiments and those in natural flashes was proved. Then, based on the local thermodynamic equation and the space charge estimation method, the required NSL formation conditions were deduced, and the space background electric field (E{sub b}) was proposed as the primary parameter for NSL formation. Finally, the critical value of E{sub b} required for the formation of NSLs in natural flashes was determined to be approximately 75 kV/m by extrapolation of the results of the simulation experiments.

  2. Behavioral response of Corophium volutator relative to experimental conditions, physical and chemical disturbances.

    PubMed

    Hellou, Jocelyne; Cheeseman, Kerri; Jouvenelle, Marie-Laure; Robertson, Sarah

    2005-12-01

    The preference/avoidance behavioral response of a widely used amphipod in toxicity tests, Corophium volutator, was investigated in relation to the presence of anthropogenic physical or chemical materials in sediments. Exposure conditions, including the density of amphipods, the depth of sediments, amount of overlying water, and exposure time, were examined for their influence on amphipods' preference for field sediments and avoidance of coarse sand. It was shown that these variables did not affect the response; thus, conditions similar to published standard toxicity tests were chosen. A gradient of sediments spiked with potential habitat disturbances that can be found on a beach or in contaminated sediments, such as those in harbors, were tested. These substances included sand, seaweed, burned wood, coal, crankcase oil, and diesel oil. To enhance the interpretation of results and decrease the variability observed when tests were conducted at different times over the summer, exposures were performed over a gradient of spike material in reference sediments. We conclude that physical obstacles added to reference sediments lead to less correlation with the behavioral response than observed with chemical interferences. Amphipods' behavior ranked harbor sediments similarly to previous studies concerning the health of intertidal mussels collected in proximity to the sediments sites. For five sites, preference of reference sediments was observed until the level of polycyclic aromatic hydrocarbons in diluted harbor sediments reached the Canadian Council of Ministers of the Environment sediment quality guidelines.

  3. Degradation of textile dyes using immobilized lignin peroxidase-like metalloporphines under mild experimental conditions

    PubMed Central

    2012-01-01

    Background Synthetic dyes represent a broad and heterogeneous class of durable pollutants, that are released in large amounts by the textile industry. The ability of two immobilized metalloporphines (structurally emulating the ligninolytic peroxidases) to bleach six chosen dyes (alizarin red S, phenosafranine, xylenol orange, methylene blue, methyl green, and methyl orange) was compared to enzymatic catalysts. To achieve a green and sustainable process, very mild conditions were chosen. Results IPS/MnTSPP was the most promising biomimetic catalyst as it was able to effectively and quickly bleach all tested dyes. Biomimetic catalysis was fully characterized: maximum activity was centered at neutral pH, in the absence of any organic solvent, using hydrogen peroxide as the oxidant. The immobilized metalloporphine kept a large part of its activity during multi-cycle use; however, well-known redox mediators were not able to increase its catalytic activity. IPS/MnTSPP was also more promising for use in industrial applications than its enzymatic counterparts (lignin peroxidase, laccase, manganese peroxidase, and horseradish peroxidase). Conclusions On the whole, the conditions were very mild (standard pressure, room temperature and neutral pH, using no organic solvents, and the most environmental-friendly oxidant) and a significant bleaching and partial mineralization of the dyes was achieved in approximately 1 h. Therefore, the process was consistent with large-scale applications. The biomimetic catalyst also had more promising features than the enzymatic catalysts. PMID:23256784

  4. Acclimation of microorganisms to harsh soil crust conditions: Experimental and genomic approaches

    NASA Astrophysics Data System (ADS)

    Raanan, Hagai; Kaplan, Aaron

    2015-04-01

    Biological soil crusts (BSC) are formed by the adhesion of sand particles to cyanobacterial exo- polysaccharides and play an important role in stabilizing sandy desert. Its destruction promotes desertification. These organisms cope with extreme temperatures, excess light and frequent hydration/dehydration cycles; the mechanisms involved are largely unknown. With the genome of newly sequenced Leptolyngbya, isolated from Nizzana BSC, we conduct comparative genomics of three desiccation tolerant cyanobacteria. This yield 46 unique genes, some of them similar to genes involve in sporulation of the gram positive bacteria Bacillus. In order to understand the molecular mechanisms taking place during desiccation we built an environmental chamber capable of simulating dynamic changes of environmental conditions in the crust. This chamber allows us to perform repetitive and accurate desiccation/rehydration experiments and follow cyanobacterial physiological and molecular response to such environmental changes. When we compared fast desiccation (less than 5 min) of isolated cyanobacteria to simulation of natural desiccation, we observed a 60% lower fluorescence recovery rate. The extent of damage from desiccation depended on the stress conditions during the dry period. These results suggest that cyanobacteria activated protection mechanisms in response to desiccation stress but which were not activated in 5 min desiccation tests. Gene expression patterns during desiccation are being analyzed in order to provide a better understanding of desiccation stress protection mechanisms.

  5. Experimental measurements of sidebranching in thermal dendrites under terrestrial-gravity and microgravity conditions.

    PubMed

    Corrigan, D P; Koss, M B; LaCombe, J C; de Jager, K D; Tennenhouse, L A; Glicksman, M E

    1999-12-01

    We perform sidebranch measurements on pure succinonitrile dendrites grown in both microgravity and terrestrial-gravity conditions for a set of supercoolings within the range 0.1-1.0 K. Two distinct types of sidebranch regions, uniform and coarsening, exist, and are characterized by the distance from the tip at which the region began, D(i), and the average spacing of sidebranches within that region, lambda(i). There does not appear to be any significant dependence on either gravity level or supercooling when D(i) or lambda(i) are normalized with respect to the radius of curvature of the tip, R. The apparently constant normalized proportionality factor between D(i), lambda(i), and R, regardless of the relative importance of diffusion and convective heat transport, demonstrates self-similarity between dendrites of different length scales propagating under various heat transfer conditions. However, when the form of the sidebranch envelope is defined by a power law relating the amplitude and relative positions of the sidebranches normalized to the radius of the tip, the form is seen to have significant variations with supercooling between the terrestrial gravity and microgravity growth dendrites. Furthermore, both the amplitude coefficient and exponent from the power-law regressions of the microgravity data are statistically different (95% confidence level) than their terrestrial counterparts.

  6. Experimental measurements of sidebranching in thermal dendrites under terrestrial-gravity and microgravity conditions

    NASA Astrophysics Data System (ADS)

    Corrigan, D. P.; Koss, M. B.; Lacombe, J. C.; de Jager, K. D.; Tennenhouse, L. A.; Glicksman, M. E.

    1999-12-01

    We perform sidebranch measurements on pure succinonitrile dendrites grown in both microgravity and terrestrial-gravity conditions for a set of supercoolings within the range 0.1-1.0 K. Two distinct types of sidebranch regions, uniform and coarsening, exist, and are characterized by the distance from the tip at which the region began, Di, and the average spacing of sidebranches within that region, λi. There does not appear to be any significant dependence on either gravity level or supercooling when Di or λi are normalized with respect to the radius of curvature of the tip, R. The apparently constant normalized proportionality factor between Di, λi, and R, regardless of the relative importance of diffusion and convective heat transport, demonstrates self-similarity between dendrites of different length scales propagating under various heat transfer conditions. However, when the form of the sidebranch envelope is defined by a power law relating the amplitude and relative positions of the sidebranches normalized to the radius of the tip, the form is seen to have significant variations with supercooling between the terrestrial gravity and microgravity growth dendrites. Furthermore, both the amplitude coefficient and exponent from the power-law regressions of the microgravity data are statistically different (95% confidence level) than their terrestrial counterparts.

  7. Tethered Chains in Poor Solvent Conditions: An Experimental Study Involving Langmuir Diblock Copolymer Monolayers

    SciTech Connect

    Kent, M.S.; Lee, L.T.; Majewski, J.; Satija, S.; Smith, G.S.

    1998-10-13

    We have employed Langmuir monolayer of highly asymmetric polydimethylsiloxane- polystyrene (PDMS-PS) diblock copolymers on dioctyl phthalate (DOP) at temperatures ranging from 22 "C to -35 `C as a model system for tethered chains in poor solvent conditions. The thicknesses of the tethered PS layers extending into the DOP subphase, measured by neutron reflection, decrease with decreasing temperature (T) over this entire r~ge. However, the v~iation with T becomes weak below -20 "C. At the ]owest T, the layer thicknesses are contracted 55 % -75 `% of their values at the theta condition (T8 = 22 "C), but are still quite swollen compared to the fully collapsed, nonsolvent limit. The contraction of the layer with decreasing T is determined as a function of surface density and molecular weight. These data are compared to universal scaling forms. The PS segments are depleted from the air surface over the entire T range, the thickness of the depletion layer increasing slightly with decreasing T. The free energy of the surface layer is probed by surface tension measurements. Negative surface pressures are observed at low coverages for both PDMS-PS and PDMS monolayer, indicating metastability toward lateral phase separation. Evidence for a trruisition from a dispersed phase to a condensed phase with decreasing T was observed in the reflectivity at very low PDMS-PS coverage.

  8. Effects of experimental conditions on mycorrhizal relationships between Pinus sylvestris and Lactarius deliciosus and unprecedented fruit-body formation of the Saffron milk cap under controlled soilless conditions.

    PubMed

    Guerin-Laguette, A; Plassard, C; Mousain, D

    2000-09-01

    The mycorrhizal relationships between pines and two edible species of Lactarius sect. Dapetes were investigated by optimizing the experimental conditions of mycelial growth and of mycorrhizal colonization of pine seedlings. In vitro mycelial growth of Lactarius deliciosus and L. sanguifluus was improved on a buffered medium containing glucose, amino acids, and vitamins. Two methods of mycorrhization of pines with Lactarius deliciosus were tested. The mycorrhizal colonization was rapid and intense under non-aseptic conditions with a low nutrient supply and without exogenous glucose. A positive influence of mycorrhizal colonization on Pinus sylvestris growth was subsequently observed. Under axenic conditions and with a high nutrient supply, mycorrhization was stimulated at 10 g/L of exogenous glucose, irrespective of the phosphorus concentration. At high phosphorus level (1 mM) and 0.1, 1.0, or 10.0 g/L glucose, growth of Pinus sylvestris was reduced by inoculation. Stability and development of Pinus spp./Lactarius deliciosus symbioses were assayed in a climatic chamber using containers filled with a synthetic substrate. Over a 2-year culture period, the root systems of the pine seedlings were heavily colonized by Lactarius deliciosus. One year following inoculation, Lactarius deliciosus fruit-body primordia appeared associated with Pinus sylvestris seedlings. Six months later, two mature basidiomata were obtained. This is the first report of soilless fruit-body formation of this edible mushroom.

  9. Experimental conditions for determination of the neutrino mass hierarchy with reactor antineutrinos

    NASA Astrophysics Data System (ADS)

    Pac, Myoung Youl

    2016-01-01

    This article reports the optimized experimental requirements to determine neutrino mass hierarchy using electron antineutrinos (νbare) generated in a nuclear reactor. The features of the neutrino mass hierarchy can be extracted from the | Δ m312 | and | Δ m322 | oscillations by applying the Fourier sine and cosine transforms to the L / E spectrum. To determine the neutrino mass hierarchy above 90% probability, the requirements on the energy resolution as a function of the baseline are studied at sin2 ⁡ 2θ13 = 0.1. If the energy resolution of the neutrino detector is less than 0.04 /√{Eν} and the determination probability obtained from Bayes' theorem is above 90%, the detector needs to be located around 48-53 km from the reactor(s) to measure the energy spectrum of νbare. These results will be helpful for setting up an experiment to determine the neutrino mass hierarchy, which is an important problem in neutrino physics.

  10. Hydrogen sulfide gas emission under turbulent conditions - an experimental approach for free-fall drops.

    PubMed

    Matias, N M; Matos, J S; Ferreira, F

    2014-01-01

    Odor nuisance and sulfide corrosion in sewers carrying septic wastewater are accelerated at points of turbulence such as drops in manholes, but accurate methods or empirical expressions to evaluate the gas stripping rate at those particular sites are still missing. With the aim of improving the current knowledge on the influence of free-fall drops on the release of hydrogen sulfide gas, an experimental set-up was built allowing different free-fall drops heights and flows. Three types of experiments were carried out: reaeration tests without sulfide; sulfide oxidation tests; and hydrogen sulfide release tests. With the increase of the free-fall drop height or of the flow, a higher rate of air-to-water mass oxygen transfer was observed. Results regarding sulfide oxidation tests with reaeration through the free-fall have shown that the oxidation rate was correlated with flow. In the hydrogen sulfide release tests, the maximum concentration in the atmosphere reached 500 ppm. Results also showed that increasing the flow rate decreased the time at which the maximum concentrations in the atmosphere were observed.

  11. Final thermal conditions override the effects of temperature history and dispersal in experimental communities.

    PubMed

    Limberger, Romana; Low-Décarie, Etienne; Fussmann, Gregor F

    2014-10-22

    Predicting the effect of climate change on biodiversity is a multifactorial problem that is complicated by potentially interactive effects with habitat properties and altered species interactions. In a microcosm experiment with communities of microalgae, we analysed whether the effect of rising temperature on diversity depended on the initial or the final temperature of the habitat, on the rate of change, on dispersal and on landscape heterogeneity. We also tested whether the response of species to temperature measured in monoculture allowed prediction of the composition of communities under rising temperature. We found that the final temperature of the habitat was the primary driver of diversity in our experimental communities. Species richness declined faster at higher temperatures. The negative effect of warming was not alleviated by a slower rate of warming or by dispersal among habitats and did not depend on the initial temperature. The response of evenness, however, did depend on the rate of change and on the initial temperature. Community composition was not predictable from monoculture assays, but higher fitness inequality (as seen by larger variance in growth rate among species in monoculture at higher temperatures) explained the faster loss of biodiversity with rising temperature.

  12. Crossing the boundary: experimental investigation of water entry conditions of V-shaped wedges

    NASA Astrophysics Data System (ADS)

    Xiao, Tingben; Yohann, Daniel; Vincent, Lionel; Jung, Sunghwan; Kanso, Eva

    2016-11-01

    Seabirds that plunge-dive at high speeds exhibit remarkable abilities to withstand and mitigate impact forces. To minimize these forces, diving birds streamline their shape at impact, entering water with their sharp beak first. Here, we investigate the impact forces on rigid V-shaped wedges crossing the air-water interface at high Weber numbers. We vary the impact velocity V by adjusting the height from which the wedge is dropped. Both a high-speed camera and a force transducer are used to characterize the impact. We found that the splash base and air cavity show little dependence on the impact velocity when rescaling by inertial time d / V , where d is the breadth of the wedge. The peak impact force occurs at time tp smaller than the submersion time ts such that the ratio tp /ts is almost constant for all wedges and impact velocities V. We also found that the maximum impact force, like drag force, scales as AV2 , where A is the cross-sectional area of the wedge. We then propose analytical models of the impact force and splash dynamics. The theoretical predictions agree well with our experimental results. We conclude by commenting on the relevance of these results to understanding the mechanics of diving seabirds. We acknowledge support from the National Science Foundation.

  13. The influence of the irradiation regime upon mycotoxins production under experimental conditions.

    PubMed

    Uralová, M; Patzeltová, N; Havlík, F

    1987-01-01

    The paper handles the problem of the inactivation of the toxinogenic strain Aspergillus flavus following the application of gamma radiation to wheat. The amount of the applied dose and of the absorbed dose of ionizing radiation upon the inhibition of mycelium growth and toxin production were defined. The aflatoxin B1 was determined by extracting in chloroform and developed on Silufol R within the choroform; aceton system. The applied doses of gamma radiation (3-30 kGy) have show that the absorbed dose does not inhibit aflatoxin production. By combining the action of gamma radiation with humidity of the wheat (humidity 13-15%; 25% irradiation 6 kGy) an inactivation was reached. With the help of toxicologico-genetical tests (the Dominant Lethal Mutations Test, the Three Generations Test) the influence was traced of contaminated, irradiated substrates upon the health of experimental animals. It follows from the results obtained that in long-term feeding with contaminated wheat irradiated by gamma rays no positive mutagenic activity has been recorded. It allows to presume that wheat of humidity of 25% contaminated by a weakly toxigenic strain Aspergillus flavus irradiated by a dose of 6 kGy, and wheat of a humidity of 13-15%, contaminated by a strongly toxinogenic strain of Aspergillus flavus, irradiated by a dose of 6 kGy, are no genetic risk for white rats.

  14. Fracturing of volcanic systems: Experimental insights into pre-eruptive conditions

    NASA Astrophysics Data System (ADS)

    Smith, Rosanna; Sammonds, Peter R.; Kilburn, Christopher R. J.

    2009-04-01

    Conditions for fracturing are a primary control on the behaviour of volcanic systems, especially during the approach to eruption. We here present the results of deformation experiments under simulated volcanic conditions on a porhyritic andesite from ancestral Mount Shasta. Andesite was chosen as a representative material because it is common at subduction-zone volcanoes, among both erupted products and country rock. We deformed the lava in tension and triaxial compression tests at strain rates of 10 - 5 s - 1 , confining pressures from 0 to 50 MPa and temperatures up to 900 °C. We also concurrently recorded acoustic emissions (AE), in order to monitor cracking activity. The results show that deformation behaviour changes significantly in the temperature range 600-750 °C. Thus, as temperatures increased across this interval, the tensile fracture toughness increased from 2.5 ± 0.5 MPa m 1/2 to 3.5 ± 1 MPa m 1/2, the compressive strength decreased from 110 ± 30 MPa to 55 ± 35 MPa (at 900 °C) and the corresponding Young's Modulus decreased from 20 ± 4 GPa to 6 ± 4 GPa. The changes occur when the deformation of the sample changes from elastic-brittle to brittle-ductile behaviour, which we attribute to the blunting of crack tips due to melting of the glass phase and enhanced crystal plasticity at high temperature. AE activity was observed in all experiments, indicating that earthquakes can be generated not only in country rock, but also in hot magma, such as may be found in lava domes and at the margins of magma conduits. In addition, the trends in accelerating AE event rates before sample failure were comparable to those seen in earthquakes before some volcanic eruptions and a minimum in the seismic b-value coincided with sample failure. Applied to volcanic systems, the results suggest that (1) andesite strength and elasticity will not be affected by temperature or pressure beyond ~ 10-100 m from active magma, (2) before eruptions, fractures propagate

  15. Active imaging systems to see through adverse conditions: Light-scattering based models and experimental validation

    NASA Astrophysics Data System (ADS)

    Riviere, Nicolas; Ceolato, Romain; Hespel, Laurent

    2014-10-01

    Onera, the French aerospace lab, develops and models active imaging systems to understand the relevant physical phenomena affecting these systems performance. As a consequence, efforts have been done on the propagation of a pulse through the atmosphere and on target geometries and surface properties. These imaging systems must operate at night in all ambient illumination and weather conditions in order to perform strategic surveillance for various worldwide operations. We have implemented codes for 2D and 3D laser imaging systems. As we aim to image a scene in the presence of rain, snow, fog or haze, we introduce such light-scattering effects in our numerical models and compare simulated images with measurements provided by commercial laser scanners.

  16. Experimental and numerical study of plastic shear instability under high-speed loading conditions

    SciTech Connect

    Sokovikov, Mikhail E-mail: naimark@icmm.ru; Chudinov, Vasiliy E-mail: naimark@icmm.ru; Bilalov, Dmitry E-mail: naimark@icmm.ru; Oborin, Vladimir E-mail: naimark@icmm.ru; Uvarov, Sergey E-mail: naimark@icmm.ru; Plekhov, Oleg E-mail: naimark@icmm.ru; Terekhina, Alena E-mail: naimark@icmm.ru; Naimark, Oleg E-mail: naimark@icmm.ru

    2014-11-14

    The behavior of specimens dynamically loaded during the split Hopkinson (Kolsky) bar tests in a regime close to simple shear conditions was studied. The lateral surface of the specimens was investigated in a real-time mode with the aid of a high-speed infra-red camera CEDIP Silver 450M. The temperature field distribution obtained at different time made it possible to trace the evolution of plastic strain localization. The process of target perforation involving plug formation and ejection was examined using a high-speed infra-red camera and a VISAR velocity measurement system. The microstructure of tested specimens was analyzed using an optical interferometer-profilometer and a scanning electron microscope. The development of plastic shear instability regions has been simulated numerically.

  17. Hyperactivity induced by prenatal BrdU exposure across several experimental conditions.

    PubMed

    Kuwagata, Makiko; Ogawa, Tetsuo; Muneoka, Katsumasa; Shioda, Seiji

    2011-12-01

    Behavioral results are sometimes not reproducible even in the positive controls of developmental neurotoxicity (DNT) tests. Effects of several factors on the results should be considered. In the present paper, we examined the effects of strain-, gender-, and test-condition differences on BrdU-induced hyperactivity. The results showed that BrdU-induced hyperactivity was reproducible in two rat strains (SD and F344 rats), rodent species (rat and mouse), and both sexes. When the level of background sound in a test room was increased, the hyperactivity was persistent, resulting in no effect of background sound on BrdU-induced hyperactivity. Thus, we have demonstrated that the BrdU-animal model is a useful positive control via prenatal exposure to validate the entire DNT test process.

  18. Hydrologic modification to improve habitat in riverine lakes: Management objectives, experimental approach, and initial conditions

    USGS Publications Warehouse

    Johnson, Barry L.; Barko, John W.; Gerasimov, Yuri; James, William F.; Litvinov, Alexander; Naimo, Teresa J.; Wiener, James G.; Gaugush, Robert F.; Rogala, James T.; Rogers, Sara J.; Schoettger, R.A.

    1996-01-01

    The Finger Lakes habitat-rehabilitation project is intended to improve physical and chemical conditions for fish in six connected back water lakes in Navigation Pool 5 of the upper Missouri River. The primary management objective is to improve water temperature, dissolved oxygen concentration and current velocity during winter for bluegills, Lepomis macrochirus, and black crappies, Pomoxis nigromaculatus, two of the primary sport fishes in the lakes. The lakes will be hydrologically altered by Installing culverts to Introduce controlled flows of oxygenated water into four lakes, and an existing unregulated culvert on a fifth lake will be equipped with a control gate to regulate inflow. These habitat modifications constitute a manipulative field experiment that will compare pre-project (1991 to summer 1993) and post-project (fall 1993 to 1996) conditions in the lakes, including hydrology, chemistry, rooted vegetation, and fish and macroinvertebrate communities. Initial data indicate that the Finger Lakes differ in water chemistry, hydrology, and macrophyte abundance. Macroinvertebrate communities also differed among lakes: species diversity was highest in lakes with dense aquatic macrophytes. The system seems to support a single fish community, although some species concentrated in individual lakes at different times. The introduction of similar flows into five of the lakes will probably reduce the existing physical and chemical differences among lakes. However, our ability to predict the effects of hydrologic modification on fish populations is limited by uncertainties concerning both the interactions of temperature, oxygen and current in winter and the biological responses of primary and secondary producers. Results from this study should provide guidance for similar habitat-rehabilitation projects in large rivers.

  19. On the Boundary Conditions at an Oscillating Contact Line: A Physical/Numerical Experimental Program

    NASA Technical Reports Server (NTRS)

    Perlin, Marc; Schultz, William W.

    1996-01-01

    We will pursue an improved physical understanding and mathematical model for the boundary condition at an oscillating contact line at high Reynolds number. We expect that the body force is locally unimportant for earth-based systems, and that the local behavior may dominate the mechanics of partially-filled reservoirs in the microgravity environment. One important space-based application for this contact-line study is for Faraday-waves. Oscillations in the direction of gravity (or acceleration) can dominate the fluid motion during take-off and reentry with large steady-state accelerations and in orbit, where fluctuations on the order of 10(exp -4)g occur about a zero mean. Our experience with Faraday waves has shown them to be 'cleaner' than those produced by vertical or horizontal oscillation of walls. They are easier to model analytically or computationally, and they do not have strong vortex formation at the bottom of the plate. Hence many, if not most, of the experiments will be performed in this manner. The importance of contact lines in the microgravity environment is well established. We will compare high resolution measurements of the velocity field (lO micro-m resolution) using particle-tracking and particle-image velocimetry as the fluid/fluid interface is approached from the lower fluid. The spatial gradients in the deviation provide additional means to determine an improved boundary condition and a measure of the slip region. Dissipation, the size of the eddy near the contact line, and hysteresis will be measured and compare to linear and nonlinear models of viscous and irrotational but dissipative models.

  20. Shear zone nucleation and deformation transient: effect of heterogeneities and loading conditions in experimentally deformed calcite

    NASA Astrophysics Data System (ADS)

    Morales, L. F. G.; Rybacki, E.; Dresen, G. H.; Kilian, R.

    2015-12-01

    In the Earth's middle to lower crust, strain is frequently localized along ductile shear zones, which commonly nucleate at structural and material heterogeneities. To investigate shear zone nucleation and development due to heterogeneities, we performed constant strain-rate (CSR) and constant stress (CS) simple shear (torsion) deformation experiments on Carrara marble samples containing weak (limestone) inclusions. The experiments were conducted in a Paterson-type gas deformation apparatus at 900 °C temperature and 400 MPa confining pressure and maximum bulk shear strains of 3. Peak shear stress was about 20 MPa for all the samples, followed by smooth weakening and steady state behavior. The strain is predominantly localized in the host marble within the process zone in front of the inclusion, defined by a zone of intense grain size reduction due to dynamic recrystallization. In CS tests a narrow shear zone developed in front of the inclusion, whereas in CSR experiments the deformation is more heterogeneously distributed, up to g=3.. In the later, secondary foliations oblique to the process zone and alternating thin, high-strain layers are common. In samples deformed at the same shear strain (g=1), the average recrystallized grain size in the process zone is similar for CS and CSR conditions. Crystallographic preferred orientation (CPO) measurements shows that different grain sizes have slightly different CPO patterns. CPO strength varies for different grain sizes, with a CPO strength peak between 40-50 μm, decreasing progressively within smaller grain size, but with secondary peaks for different coarse-grained sizes. Our observations suggest that the initial formation and transient deformation of shear zones is strongly affected by loading conditions.

  1. A modified device for long term sampling of parotid saliva in various experimental conditions.

    PubMed

    Takayanagi, A; Nomura, T; Yamanaka, S; Takaesu, Y

    1995-05-01

    A parotid cup has been widely used as an intraoral device for the collection of parotid saliva. However, in long duration sampling, the cup tends to disconnect under circumstances such as mastication, sleep or physical exercise. We have designed a modified device of parotid cup for saliva collection to overcome these unfavorable conditions. The parotid cup was modified by fixing it to the bite-plate appliance which was adjusted individually to the occlusal plane in order to avoid disconnection of the cup under varying conditions. Using this device, we could measure salivary flow rate during mastication, sleep or physical exercise. Additional advantages of this device are that it is easy to make with acrylic resin and is inexpensive. The preliminary study using this device showed that flow rates of unstimulated parotid saliva varied from 0.06 +/- 0.04 ml/min. to 0.16 +/- 0.10 ml/min. (mean +/- s.d) from 7 a.m. to 12 p.m. in 7 subjects. In five subjects, the flow rate of parotid saliva during meal (lunch) was much higher than that of resting on a chair, playing table tennis, or sleeping at night for 6-8 hours. This might be considered due to the stimuli of the meal content. Flow rates of saliva were also examined with various stimuli. The results showed that salty pickled plum > sour lemon juice > 10% ascorbic acid > sweet milky candy > 1% ascorbic acid. These data suggest that our modified device is useful for various experiments in salivary research.

  2. An experimental study of Li partitioning between olivine and diopside at mantle conditions

    NASA Astrophysics Data System (ADS)

    Yakob, J. L.; Feineman, M. D.; Penniston-Dorland, S. C.; Eggler, D. H.

    2010-12-01

    Measured 7Li/6Li of mineral separates from mantle xenoliths from diverse localities show unexpectedly large differences between olivines and pyroxenes, often with lighter Li found in the pyroxenes (Jeffcoate et al., 2007; Rudnick and Ionov, 2007; Ionov and Seitz, 2008). Although changes in isotopic fractionation with temperature could explain the differences, a kinetic isotope effect is as likely. Because 6Li diffuses faster than 7Li, bulk lithium exchange between two phases could result in dynamic isotopic fractionation, with the receiving phase becoming lighter and the donating phase becoming heavier. Thus if Li becomes more compatible in cpx upon cooling, that is, if DLiol/cpx is temperature-dependent, the diffusive exchange of Li will generate temporary 6Li enrichment in cpx and depletion in olivine. Experiments were conducted using a piston cylinder apparatus at 1100°C and 1.4 GPa (1-5 days) to determine DLiol/cpx. San Carlos olivine and Dekalb diopside were finely ground for starting materials. A mixture of olivine (52 wt%), diopside (34 wt%), albite (7 wt%), and quartz (7 wt%) powders (0.0145 g) was loaded into a Pt capsule inside of a Ni crucible. Milli-Q water with 100 ppm Li and 500 ppm Ba (obtained through dilution of stock solutions) was added (0.1100 g) to serve as the lithium source. Lithium concentrations in olivine and diopside from experiments held for 1, 3, and 5 days were determined by laser ablation ICP-MS. Partition coefficients DLiol/cpx from runs at 3 and 5 days are, within error, the same, 1.9 (0.3). These fall in the lower portion of the range, D = 2-7, of limited previous measurements (Brenan et al., 1998b, Blundy and Dalton, 2000; Caciagli-Warman 2010). Partitioning experiments at 700 and 900°C are ongoing. References Blundy, J. and Dalton, J. (2000) Experimental comparison of trace element partitioning between clinopyroxene and melt in carbonate and silicate systems, and implications for mantle metasomatism. Contrib. Mineral. Petrol

  3. Molecular alteration of marine dissolved organic matter under experimental hydrothermal conditions

    NASA Astrophysics Data System (ADS)

    Hawkes, Jeffrey A.; Hansen, Christian T.; Goldhammer, Tobias; Bach, Wolfgang; Dittmar, Thorsten

    2016-02-01

    Marine dissolved organic matter (DOM) is a large (660 Pg) pool of reduced carbon that is subject to thermal alteration in hydrothermal systems and sedimentary basins. In natural high-temperature hydrothermal systems, DOM is almost completely removed, but the mechanism and temperature dependence of this removal have not been studied to date. We investigated molecular-level changes to DOM that was solid-phase extracted (SPE-DOM) from the deep ocean of the North Pacific Ocean. This complex molecular mixture was experimentally exposed to temperatures between 100 and 380 °C over the course of two weeks in artificial seawater, and was then characterised on a molecular level via ultrahigh-resolution Fourier-transform ion cyclotron mass spectrometry (FT-ICR-MS). Almost 93% of SPE-DOM was removed by the treatment at 380 °C, and this removal was accompanied by a consistent pattern of SPE-DOM alteration across the temperatures studied. Higher molecular weight and more oxygen rich compounds were preferentially removed, suggesting that decarboxylation and dehydration of carboxylic acid and alcohol groups are the most rapid degradation mechanisms. Nitrogen containing compounds followed the same overall trends as those containing just C, H and O up to 300 °C. Above this temperature, the most highly altered samples contained very little of the original character of marine DOM, instead being mainly composed of very low intensity N- and S- containing molecules with a high H/C ratio (>1.5). Our results suggest that abiotic hydrothermal alteration of SPE-DOM may already occur at temperatures above 68 °C. Our experiments were conducted without a sedimentary or mineral phase, and demonstrate that profound molecular alteration and almost complete removal of marine SPE-DOM requires nothing more than heating in a seawater matrix.

  4. Fungal Diversity in Permafrost and Tallgrass Prairie Soils under Experimental Warming Conditions

    PubMed Central

    StLouis, Derek; Cole, James R.; Luo, Yiqi; Wu, Liyou; Schuur, E. A. G; Zhou, Jizhong; Tiedje, James M.

    2013-01-01

    Soil fungi play a major role in terrestrial ecosystem functioning through interactions with soil structure, plants, micro- and mesofauna, and nutrient cycling through predation, pathogenesis, mutualistic, and saprotrophic roles. The diversity of soil fungi was assessed by sequencing their 28S rRNA gene in Alaskan permafrost and Oklahoma tallgrass prairie soils at experimental sites where the effect of climate warming is under investigation. A total of 226,695 reads were classified into 1,063 genera, covering 62% of the reference data set. Using the Bayesian Classifier offered by the Ribosomal Database Project (RDP) with 50% bootstrapping classification confidence, approximately 70% of sequences were returned as “unclassified” at the genus level, although the majority (∼65%) were classified at the class level, which provided insight into these lesser-known fungal lineages. Those unclassified at the genus level were subjected to BLAST analysis against the ARB-SILVA database, where ∼50% most closely matched nonfungal taxa. Compared to the more abundant sequences, a higher proportion of rare operational taxonomic units (OTU) were successfully classified to genera at 50% bootstrap confidence, indicating that the fungal rare biosphere in these sites is not composed of sequencing artifacts. There was no significant effect after 1 year of warming on the fungal community structure at both sites, except perhaps for a few minor members, but there was a significant effect of sample depth in the permafrost soils. Despite overall significant community structure differences driven by variations in OTU dominance, the prairie and permafrost soils shared 90% and 63% of all fungal sequences, respectively, indicating a fungal “seed bank” common between both sites. PMID:24014534

  5. Velocity and Vorticity Fields of a Turbulent Plume under different experimental conditions

    NASA Astrophysics Data System (ADS)

    Matulka, A. M.; Gonzalez-Nieto, P. L.; Redondo, J. M.; Tarquis, A. M.

    2012-04-01

    The geophysical and practical importance and the applications of turbulent plumes as generators of strong dispersion processes are clearly recognized. In geophysics and astrophysics, it is usual to model as a jet or plume the generation mechanism of turbulent mixing as a part of a dispersion process [1-3]. An interesting geophysical problem is the study of volcanic plumes [2], which are columns of hot volcanic ash and gas emitted into the atmosphere during an explosive volcanic eruption. Another interesting like-plume phenomenon can be observed where a stream, usually a river, empties into a lake, sea or ocean, generating a river plume [3,4]. Turbulent plumes are fluid motions whose primary source of kinetic energy and momentum flux is due to body forces that arise from density inhomogeneities. The plume boundary acts as an interface across which ambient fluid is entrained, and the plume boundary moves at the velocity of the plume fluid. The difference between the plume-fluid radial velocity and the total fluid velocity quantifies in a natural way the purely horizontal entrainment flux of ambient fluid into the plume across the phase boundary at the plume edge [5,6]. We show some results of research on a single turbulent plume as well as on the structure of the interaction between different plumes and jets, We measure and compare velocity and vorticity fields occurring in different experimental configurations (Parametrized by the Atwood number and the initial potential energy as well as the Plume-Jet length scale). This work is based on experiments that have been performed in GFD laboratories (IPD and UPC) using visualizations methods (LIF,PIV) and advanced multiscaling techniques. We calculate velocity and vorticity PDFs and the evolution of the structure of stratified decaying, with DigFlow and Imacalc programs (Matulka 2010)[7], where video sequence processing provides a range of global and local descriptor features designed specifically for analysing fluid

  6. Physiological response of invasive mussel Limnoperna fortunei (Dunker, 1857) (Bivalvia: Mytilidae) submitted to transport and experimental conditions.

    PubMed

    Cordeiro, N I S; Andrade, J T M; Montresor, L C; Luz, D M R; Araújo, J M; Martinez, C B; Pinheiro, J; Vidigal, T H D A

    2017-03-01

    Successful animal rearing under laboratory conditions for commercial processes or laboratory experiments is a complex chain that includes several stressors (e.g., sampling and transport) and incurs, as a consequence, the reduction of natural animal conditions, economic losses and inconsistent and unreliable biological results. Since the invasion of the bivalve Limnoperna fortunei (Dunker, 1857) in South America, several studies have been performed to help control and manage this fouling pest in industrial plants that use raw water. Relatively little attention has been given to the laboratory rearing procedure of L. fortunei, its condition when exposed to a stressor or its acclimation into laboratory conditions. Considering this issue, the aims of this study are to (i) investigate L. fortunei physiological responses when submitted to the depuration process and subsequent air transport (without water/dry condition) at two temperatures, based on glycogen concentrations, and (ii) monitor the glycogen concentrations in different groups when maintained for 28 days under laboratory conditions. Based on the obtained results, depuration did not affect either of the groups when they were submitted to approximately eight hours of transport. The variation in glycogen concentration among the specimens that were obtained from the field under depurated and non-depurated conditions was significant only in the first week of laboratory growth for the non-depurated group and in the second week for the depurated group. In addition, the tested temperature did not affect either of the groups that were submitted to transport. The glycogen concentrations were similar to those of the specimens that were obtained from the field in third week, which suggests that the specimens acclimated to laboratory conditions during this period of time. Thus, the results indicate that the air transport and acclimation time can be successfully incorporated into experimental studies of L. fortunei. Finally

  7. Experimental and theoretical investigations of Cs-Ba vapor tacitron inverter for power conditioning in space power systems

    SciTech Connect

    El-Genk, M.; Murray, C.; Wernsman, B.

    1993-01-01

    The operation characteristics of the Cs-Ba tacitron as a switch are investigated experimentally in three modes: (a) breakdown mode, (b) I-V mode, and (c) current modulation mode. The switching frequency, grid potentials for ignition and extinguishing of discharge, and the Cs pressure and emission conditions (Ba pressure and emitter temperature) for stable current modulation are determined. The experimental data is also used to determine the off-time required for successful ignition, and the effects of the aforementioned operation parameters on the ignition duty cycle threshold for stable modulation. Operation parameters measured include switching frequency up to 20 kHz, hold-off voltage up to 180 V, current densities in excess of 15 A/cm[sup 2], switch power density of 1 kW/cm[sup 2]. and a switching efficiency in excess of 90% at collector C: realer than 30 V. The voltage drop strongly depends on the Cs pressure and to a lesser extent on the emission conditions. Increasing the Cs pressure and/or the emission current lowers the voltage drop, however, for the same initial Cs pressure and emission conditions, the voltage drop in the I-V mode is usually lower than that during current modulation. As long as the discharge current is kept lower that the.emission current, the voltage drop during stable current modulation could be as low as 3 V.

  8. Toward Obtaining the Experimental Constraints on the Role of Water on Melting Under the Lower Mantle Conditions

    NASA Astrophysics Data System (ADS)

    Amulele, G.; Lee, K. K.; Karato, S.

    2012-12-01

    Water and other volatile components (such as carbon dioxide) are known to have important influence on the melting behavior of silicates. The role of these components on the melting under the upper mantle conditions is now reasonably well understood. Recent experimental studies in our lab as well as some of the previous studies do show that water has an important influence on the melting relationship under the lower mantle conditions. The influence of water is not only to reduce the solidus but also to change the composition of the melt to (Mg,Fe)O rich. Quantifying these observations is essential in the understanding of chemical evolution of Earth and other planets. However, there are several challenges in performing these experimental studies. In this presentation, we discuss the issue of quantifying the water effects with special attention to the capability of preserving water content during the high pressure-temperature experiments. The issue of the preservation of water is important firstly because water could escape from a capsule during an experiment, and secondly because the melt is unquenchable in a commonly used processes under the lower mantle conditions. A commonly used practice is to identify the deficit of EPMA measurement from 100% to the water content, but there is no sound basis for this practice. In this presentation, we will show some preliminary results of our new approach to quantify the water content from the high-pressure run products containing melts.

  9. Estimates for ELF effects: noise-based thresholds and the number of experimental conditions required for empirical searches.

    PubMed

    Weaver, J C; Astumian, R D

    1992-01-01

    Interactions between physical fields and biological systems present difficult conceptual problems. Complete biological systems, even isolated cells, are exceedingly complex. This argues against the pursuit of theoretical models, with the possible consequence that only experimental studies should be considered. In contrast, electromagnetic fields are well understood. Further, some subsystems of cells (viz. cell membranes) can be reasonably represented by physical models. This argues for the pursuit of theoretical models which quantitatively describe interactions of electromagnetic fields with that subsystem. Here we consider the hypothesis that electric fields, not magnetic fields, are the source of interactions, From this it follows that the cell membrane is a relevant subsystem, as the membrane is much more resistive than the intra- or extracellular regions. A general class of interactions is considered: electroconformational changes associated with the membrane. Expected results of such as approach include the dependence of the interaction on key parameters (e.g., cell size, field magnitude, frequency, and exposure time), constraints on threshold exposure conditions, and insight into how experiments might be designed. Further, because it is well established that strong and moderate electric fields interact significantly with cells, estimates of the extrapolated interaction for weaker fields can be sought. By employing signal-to-noise (S/N) ratio criteria, theoretical models can also be used to estimate threshold magnitudes. These estimates are particularly relevant to in vitro conditions, for which most biologically generated background fields are absent. Finally, we argue that if theoretical model predictions are unavailable to guide the selection of experimental conditions, an overwhelmingly large number of different conditions will be needed to find, establish, and characterize bioelectromagnetic effects in an empirical search. This is contrasted with well

  10. Experimental investigation of supersonic low pressure air plasma flows obtained with different arc-jet operating conditions

    SciTech Connect

    Lago, Viviana; Ndiaye, Abdoul-Aziz

    2012-11-27

    A stationary arc-jet plasma flow at low pressure is used to simulate some properties of the gas flow surrounding a vehicle during its entry into celestial body's atmospheres. This paper presents an experimental study concerning plasmas simulating a re-entry into our planet. Optical measurements have been carried out for several operating plasma conditions in the free stream, and in the shock layer formed in front of a flat cylindrical plate, placed in the plasma jet. The analysis of the spectral radiation enabled the identification of the emitting species, the determination of the rotational and vibrational temperatures in the free-stream and in the shock layer and the determination of the distance of the shock to the flat plate face. Some plasma fluid parameters like, stagnation pressure, specific enthalpy and heat flux have been determined experimentally along the plasma-jet axis.

  11. Experimental Investigation of the Mechanical Behavior in Unloading Conditions of Sandstone After High-Temperature Treatment

    NASA Astrophysics Data System (ADS)

    Ding, Qi-Le; Ju, Feng; Mao, Xian-Biao; Ma, Dan; Yu, Bang-Yong; Song, Shuai-Bing

    2016-07-01

    A detailed understanding of damage evolution in rock after high-temperature treatment in unloading conditions is extremely important in underground engineering applications, such as the disposal of highly radioactive nuclear waste, underground coal gasification, and post-disaster reconstruction. We have studied the effects of temperature (200, 400, 600 and 800 °C) and confining pressure (20, 30 and 40 MPa) on the mechanical properties of sandstone. Scanning electron microscopy studies revealed that at temperatures exceeding 400 °C, new cracks formed, and original cracks extended substantially. When the confining pressure was 20 MPa, a temperature increase from 400 to 800 °C resulted in a 75.2% increase in peak strain, a decrease in Young's modulus and peak strength of 62.5 and 35.8 %, respectively, and transition of the failure mechanism from brittleness to ductility. In the triaxial compression tests, the specimen deformed in a more obvious ductile failure manner at higher confining pressure, whereas in the unloading confining pressure experiments, brittle failure was more obvious when the initial confining pressure was higher. We focused on the effects of temperature and initial confining pressure on peak effective loading stress and peak ductile deformation during unloading. At temperatures of >400 °C, the peak ductile deformation increased rapidly with increases in the high temperature treatment or initial confining pressure. The peak effective loading stress decreased sharply with increased temperature but barely changed when the initial confining pressure was varied.

  12. Experimental Analysis of a 2-D Lightcraft in Static and Hypersonic Conditions

    NASA Astrophysics Data System (ADS)

    Salvador, Israel I.; Myrabo, Leik N.; Minucci, Marco A. S.; de Oliveira, Antonio C.; Rego, Israel S.; Toro, Paulo G. P.; Channes, José B.

    2010-05-01

    Aiming at the hypersonic phase of the Earth-to-Orbit trajectory for a laser propelled vehicle, a 2-D Lightcraft model was designed to be tested at the T3 Hypersonic Shock Tunnel at the Henry T. Nagamatsu Laboratory for Aerodynamics and Hypersonics. A high energy laser pulse was supplied by a Lumonics TEA 620 laser system operating in unstable resonator cavity mode. The experiments were performed at quiescent (no flow) conditions and at a nominal Mach number of 9.2. A Schlieren visualization apparatus was used in order to access both the cold hypersonic flowfield structure (without laser deposition) and the time dependent flowfield structure, taking place after the laser induced breakdown inside the absorption chamber. The model was fitted with piezoelectric pressure transducers and surface junction thermocouples in an attempt to measure pressure and heat transfer time dependent distributions at the internal surfaces of the model's absorption chamber. The 2-D model followed a modular design for flexibility on the analysis of geometrical features contribution on the expansion of the laser induced blast wave. Finally, future evolution of the experiments being currently pursued is addressed.

  13. Experimental determination of the electrical resistivity of iron at Earth's core conditions.

    PubMed

    Ohta, Kenji; Kuwayama, Yasuhiro; Hirose, Kei; Shimizu, Katsuya; Ohishi, Yasuo

    2016-06-02

    Earth continuously generates a dipole magnetic field in its convecting liquid outer core by a self-sustained dynamo action. Metallic iron is a dominant component of the outer core, so its electrical and thermal conductivity controls the dynamics and thermal evolution of Earth's core. However, in spite of extensive research, the transport properties of iron under core conditions are still controversial. Since free electrons are a primary carrier of both electric current and heat, the electron scattering mechanism in iron under high pressure and temperature holds the key to understanding the transport properties of planetary cores. Here we measure the electrical resistivity (the reciprocal of electrical conductivity) of iron at the high temperatures (up to 4,500 kelvin) and pressures (megabars) of Earth's core in a laser-heated diamond-anvil cell. The value measured for the resistivity of iron is even lower than the value extrapolated from high-pressure, low-temperature data using the Bloch-Grüneisen law, which considers only the electron-phonon scattering. This shows that the iron resistivity is strongly suppressed by the resistivity saturation effect at high temperatures. The low electrical resistivity of iron indicates the high thermal conductivity of Earth's core, suggesting rapid core cooling and a young inner core less than 0.7 billion years old. Therefore, an abrupt increase in palaeomagnetic field intensity around 1.3 billion years ago may not be related to the birth of the inner core.

  14. Experimental determination of the electrical resistivity of iron at Earth’s core conditions

    NASA Astrophysics Data System (ADS)

    Ohta, Kenji; Kuwayama, Yasuhiro; Hirose, Kei; Shimizu, Katsuya; Ohishi, Yasuo

    2016-06-01

    Earth continuously generates a dipole magnetic field in its convecting liquid outer core by a self-sustained dynamo action. Metallic iron is a dominant component of the outer core, so its electrical and thermal conductivity controls the dynamics and thermal evolution of Earth’s core. However, in spite of extensive research, the transport properties of iron under core conditions are still controversial. Since free electrons are a primary carrier of both electric current and heat, the electron scattering mechanism in iron under high pressure and temperature holds the key to understanding the transport properties of planetary cores. Here we measure the electrical resistivity (the reciprocal of electrical conductivity) of iron at the high temperatures (up to 4,500 kelvin) and pressures (megabars) of Earth’s core in a laser-heated diamond-anvil cell. The value measured for the resistivity of iron is even lower than the value extrapolated from high-pressure, low-temperature data using the Bloch-Grüneisen law, which considers only the electron-phonon scattering. This shows that the iron resistivity is strongly suppressed by the resistivity saturation effect at high temperatures. The low electrical resistivity of iron indicates the high thermal conductivity of Earth’s core, suggesting rapid core cooling and a young inner core less than 0.7 billion years old. Therefore, an abrupt increase in palaeomagnetic field intensity around 1.3 billion years ago may not be related to the birth of the inner core.

  15. Experimental investigation on the causes for pellet fragmentation under LOCA conditions

    NASA Astrophysics Data System (ADS)

    Bianco, A.; Vitanza, C.; Seidl, M.; Wensauer, A.; Faber, W.; Macián-Juan, R.

    2015-10-01

    This paper addresses a separate effect experiment performed with irradiated fuel to study fuel fragmentation and fission gas release during a loss of coolant accident (LOCA). The paper presents a qualitative and quantitative investigation of the effects of the removal of the geometrical constraint provided by the cladding and the removal of the constraint given by the rod internal pressure in determining the extent of fuel fragmentation and fission gas release during a LOCA for fuel segments with a burnup of approximately 52 MWd/kgU. A review of previous LOCA tests was the starting point for the identification of these constraints and for the selection of the fuel rod burnup, the experiment's procedure and the boundary conditions. An out-of-pile test was considered representative for the scope, and the experiment was performed at the Halden Reactor Project hot cell in Kjeller (Norway) with heat provided by an electric oven. Three fuel rod segments were studied: 1) a fuel segment that experienced only ballooning without burst, 2) a fuel segment that experienced ballooning and burst and 3) a fuel segment that experienced neither ballooning nor burst. The neutron radiography and fuel fragment sifting showed that both cladding constraint and internal pressure play a role in the formation of fuel cracks and fragmentation, and the study of the fission gas release during the transient showed that removing the cladding constraint or the internal pressure increased the amount of fission gas release.

  16. Experimental Study of the Influence of Surface Conditions on Explosive Electron Emission From a Pin Cathode

    NASA Astrophysics Data System (ADS)

    Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Parkevich, E. V.; Tilikin, I. N.; Mingaleev, A. R.; Agafonov, A. V.

    2016-10-01

    Most theories of Explosive Electron Emission are based on the idea of cathode flares developing after explosion of metal whiskers on the cathode surface. The spatial structure of the flare, its origin and the process of flare development are still a matter of conjecture. In this work we used picosecond duration high resolution laser probing and X-pinch point-projection X-ray radiography to directly observe whisker explosion in a high-current diode. Pin cathodes made from thin 5-25 μm W, Cu or Mo wires were used as the load in return current circuits of hybrid X-pinches on the XP and BIN pulsers. Pin length, pin-anode gap and wire surface conditions were varied over a wide range. The diode current and voltage were measured. In experiments with small wire-anode gap (0.1 - 1 mm) development of the expanded dense core of the wire was observed except with lengths of 100-200 microns. Strong mitigation of the electron emission was observed in experiments with heated pins. Work at Cornell was supported by the NNSA Stewardship Sciences Academic Programs under DOE Cooperative Agreement No. DE-NA0001836. The work in Lebedev Institute was sponsored by the Russian Foundation for Basic Research Project No. 140201206.

  17. Damage of Elastomeric Matrix Composites (EMC-rubbers) Under Static Loading Conditions: Experimental and Numerical Study

    SciTech Connect

    Ayari, F.

    2011-01-17

    Elastomeric matrix composites (EMC-rubbers) are considered as isotropic hyper elastic incompressible materials under static loading conditions. As a rubber material element cannot be extended to an infinite stretch ratio, a damage mechanism at large strain is considered. The phenomenon of cavitation plays an important role in the damage of EMCs and influences the toughening mechanism of rubber-modified plastics. Indeed, cavitation in elastomers is thought to be initiated from flaws, which grow primarily due to a hydrostatic tensile stress and ahead of the crack; there will not only be a high stress perpendicular to the plane of the crack but also significant stress components in the other direction. However, there exists historically much discussion on the evolution of the cavitation in elastomers under monotonic and/or static solicitation. Mainly, cavitation instability occurs when the stress levels are sufficiently high so that the void expansion rate becomes infinitely large. Many research works have been performed to understand the effects of rubber cavitation on toughening of plastics. In fact, the cavitation phenomenon is not well known in detail. The most popular idea states that the cavitation is related to the existence of the gas bubbles trapped in the material during the production stage and the growing of the cavities would then be the result of the growing gas bubbles. Further, instable failure mechanism at the end of the cavitation is not well known too.

  18. Experimental and modeling investigation of CO2 dissociation in Mars entry condition

    NASA Astrophysics Data System (ADS)

    Lin, Xin; Chen, Lianzhong; Peng, Jinlong; Li, Jinping; Li, Fei; Yu, Xilong

    2016-10-01

    Shock tube experiments are carried out to study the physical and chemical processes during a vehicle entry into the Mars atmosphere. The facility to establish a strong shock wave is a shock tube which is driven by combustion of hydrogen and oxygen. Measurements of rotational and vibrational temperature behind the shock wave are realized thanks to optical emission spectroscopy (OES). In parallel, tunable diode laser absorption spectroscopy (TDLAS) is utilized to diagnose one absorption line of CO near 2.33 µm. Combined with these temperature results using OES, CO concentration in the thermal equilibrium region is derived, which is 2.91 × 1017 cm-3, corresponding to equilibrium temperature equals to 7000 ± 400 K. Moreover, a thermochemical code, based on Park's two-temperature theory, for studying chemical and physical processes is developed for Mars entry conditions. Some comparisons between experiments and calculations are presented. Such a two-temperature model fails to reproduce non-equilibrium temperatures and mole fractions but suitable for equilibrium temperature predictions.

  19. Experimental validation of an undersea free space laser network simulator in turbid coastal conditions

    NASA Astrophysics Data System (ADS)

    Rashkin, David; Dalgleish, Fraser; Cardei, Ionut; Ouyang, Bing; Vuorenkoski, Anni; Cardei, Mihaela

    2013-06-01

    Mobile, high throughput mid-range data communications and robust real-time data networking in the subsea environment that can accommodate high bandwidth sensors such as optical imagers have a potentially high impact as enabling technologies for a variety of future subsea operations in the areas of distributed sensing and real-time wireless feedback and control of unmanned undersea vehicles. Although much work has been done recently in the field of undersea optical free space communications and networking, to date there has yet to be an implementation of a complete multi-node undersea wireless optical data communications network. The deployment and testing of optical wireless network equipment in the undersea environment is expensive and time-consuming, and there is a clear need for a network simulation framework that will allow researchers to evaluate the performances of different networking concepts/configurations under realistic operational and environmental constraints. This paper describes a network simulation approach that uses an accurate time dependent Monte Carlo channel model to simulate the networking physical layer, which can be used in conjunction with higher network layer protocols to simulate larger scale network performance and to help determine hardware requirements for overall network system design in a variety of undersea channel conditions.

  20. Damage of Elastomeric Matrix Composites (EMC-rubbers) Under Static Loading Conditions: Experimental and Numerical Study

    NASA Astrophysics Data System (ADS)

    Ayari, F.; Bayraktar, E.; Zghal, A.

    2011-01-01

    Elastomeric matrix composites (EMC-rubbers) are considered as isotropic hyper elastic incompressible materials under static loading conditions. As a rubber material element cannot be extended to an infinite stretch ratio, a damage mechanism at large strain is considered. The phenomenon of cavitation plays an important role in the damage of EMCs and influences the toughening mechanism of rubber-modified plastics. Indeed, cavitation in elastomers is thought to be initiated from flaws, which grow primarily due to a hydrostatic tensile stress and ahead of the crack; there will not only be a high stress perpendicular to the plane of the crack but also significant stress components in the other direction. However, there exists historically much discussion on the evolution of the cavitation in elastomers under monotonic and/or static solicitation. Mainly, cavitation instability occurs when the stress levels are sufficiently high so that the void expansion rate becomes infinitely large. Many research works have been performed to understand the effects of rubber cavitation on toughening of plastics. In fact, the cavitation phenomenon is not well known in detail. The most popular idea states that the cavitation is related to the existence of the gas bubbles trapped in the material during the production stage and the growing of the cavities would then be the result of the growing gas bubbles. Further, instable failure mechanism at the end of the cavitation is not well known too.

  1. Variability of human brain and muscle optical pathlength in different experimental conditions

    NASA Astrophysics Data System (ADS)

    Ferrari, Marco; Wei, Qingnong; De Blasi, Roberto A.; Quaresima, Valentina; Zaccanti, Giovanni

    1993-09-01

    Pathlength can be evaluated by measuring the time taken from a picosecond (psec) near infrared (IR) laser pulse to cross tissue. Differential pathlength factor (DPF) is calculated by dividing the mean pathlength by the inter-fiber distance. Data on DPF variability on humans are scarce. We investigated the forehead and forearm DPF in resting conditions and dynamically during brain hypoxic hypoxia, muscle ischemia and voluntary isometric exercise. At 3 cm inter optode spacing DPF at 800 nm was 4.3 +/- 0.2 (n equals 14, mean +/- SD) on the forearm, and 6.5 +/- 0.5 (n equals 8) on the forehead. Brain, muscle, and breast DPF values were almost constant over the inter optode spacing 2.5 - 4 cm. DPF was roughly constant in the central region of forehead. DPF drastically decreased under the fronto- temporal junction for the presence of muscle in the optical field. DPF decreased 5 - 10% during forearm ischemia with and without maximal voluntary contraction and during brain hypoxic hypoxia.

  2. Arsenic-induced phosphate limitation under experimental Early Proterozoic oceanic conditions

    NASA Astrophysics Data System (ADS)

    Chi Fru, Ernest; Hemmingsson, Christoffer; Holm, Mikaela; Chiu, Beverly; Iñiguez, Enrique

    2016-01-01

    Comparison of phosphorus concentrations associated with modern hydrothermal Fe(III)(oxyhydr)oxides and ancient Fe(III) oxide-rich iron formations, is used to estimate bioavailable Precambrian marine phosphorus (P) concentrations. This led to the proposition of a low dissolved P budget of ∼10-25% of present-day levels, before ∼1.9 billion years ago. Estimates incorporating ancient marine Si levels ≥ 0.67 mM instead suggested global dissolved P levels greater than today. Here we unite current experimental models that have considered NaCl solutions containing elevated dissolved Fe(II), Si, Ca2+ and Mg2+ ions in the incorporation of P in Precambrian marine Fe(III)(oxyhydr)oxides, in addition to arsenic as a hydrothermal proxy. We show that the coprecipitation of dissolved P and Fe(III)(oxyhydr)oxides from arsenic-rich marine waters produces an average P distribution coefficient of ∼0.072 (± 0.01) μM-1. This is comparable to the ∼ 0.07 μM-1 predicted for Fe(III)(oxyhydr)oxides in modern arsenic-rich, submarine hydrothermal settings, from which the lower Early Proterozoic dissolved marine P concentrations were predicted. As/P molar ratios below modern seawater ratios removed the negative feedback effect high Si impose on P scavenging by Fe(III)(oxyhydr)oxides. The binding of As(III) to Fe(III)(oxyhydr)oxides exhibits a lower competitive influence on P fixation. As(V) that likely became prominent in the surficially oxidized Early Proterozoic oceans induced dissolved P limitation because of preferential P sequestration at the expense of dissolved As(V) enrichment. The control of As on P scavenging by the precipitating Fe(III)(oxyhydr)oxides is strong regardless of common seawater cations (Mg2+ and Ca2+). The data suggest that the application of Si and Fe(III)(oxyhydr)oxides as an ancient seawater P proxy should consider chemical variability between depositional basins, taking into account the rather strong role hydrothermal arsenic has on the distribution of P

  3. A Computational and Experimental Study of Ignition Behavior of Gasoline Surrogate Fuels Under Low-Temperature Combustion Conditions

    NASA Astrophysics Data System (ADS)

    Han, J.; Haworth, D. C.; Kalaskar, V. B.; Boehman, A. L.

    2016-11-01

    One strategy for next-generation engines is low-temperature compression ignition of gasoline. Reaction pathways that are not relevant for high-temperature flame propagation are activated under these conditions, and the ignition behavior of these fuels under low-temperature conditions has not been widely explored. Here the ignition behavior of gasoline and two- and three-component surrogates has been studied experimentally and computationally over a range of operating conditions of interest for low-temperature engine combustion. Experiments were performed in a single-cylinder research engine. For each fuel blend, the critical compression ratio (lowest compression ratio at which the main ignition occurs) was determined over a range of operating conditions, by varying one parameter at a time with all other parameters held fixed. A simplified CFD model that considers detailed chemical kinetics was used to simulate the experiment. The focus of the study is to determine which surrogate fuel mixtures and chemical mechanisms are able to capture the ignition behavior of gasoline under these conditions. For example, different ignition behavior is found for different surrogate mixtures that all have the same Research Octane Number, and it is important to capture this behavior in CFD models.

  4. Towards Defining Adequate Lithium Trials for Individuals with Mental Retardation and Mental Illness.

    ERIC Educational Resources Information Center

    Pary, Robert J.

    1991-01-01

    Use of lithium with mentally retarded individuals with psychiatric conditions and/or behavior disturbances is discussed. The paper describes components of an adequate clinical trial and reviews case studies and double-blind cases. The paper concludes that aggression is the best indicator for lithium use, and reviews treatment parameters and…

  5. [Application of operant conditioning techniques to forensic toxicology: experimental studies on alcohol and abusable drugs].

    PubMed

    Hishida, S

    1996-10-01

    This paper describes some experiments that apply the operant conditioning techniques to forensic toxicological research. These techniques may be useful in investigating the mechanisms of action, toxic symptoms, legal competence and drug metabolism associated with substance abuse such as abuse of alcohol, psychotropic drugs, narcotics, stimulants, and organic solvents. 1) Genetic research on alcohol preference in rats. We applied operant conditioning to investigate alcohol preference in rats and constructed an apparatus for the measurement of discriminated operate responses for water or alcohol reinforcement in rat. This apparatus is a modified Skinner box with a one-lever two-liquid system. Fixed ratio-10 (FR-10) schedules of reinforcement are used to increase the work of the rat before it obtains the reinforcement. The voluntary choice of water or 10% ethanol by the rat can be assessed quantitatively by measuring the lever-pushing responses. It is an extremely useful method for measuring the real alcohol preference of rats. A rat was kept in a Skinner box overnight. The numbers of responses and reinforcement for water and ethanol and the volumes of the two liquids consumed were recorded. The ratio of ethanol reinforcement was defined as the number of ethanol reinforcement to the total number of ethanol and water reinforcement. The ratio of ethanol intake was defined as the volume of ethanol consumed to the volume of water and ethanol consumed. Ethanol consumption per g body weight was calculated from the volume of ethanol consumed by the rat. We used this apparatus to investigate alcohol preference of more than 300 Wistar Albino Rats, and divided them into a high alcohol preference (HAP) group and a low alcohol preference (LAP) group. Inbreeding between littermates was conducted in each of the HAP and LAP groups. The liver tissue of each offspring was obtained and the cytosol fraction was collected and subjected to isoelectric focusing using polyacrylamide gel

  6. Molecular dynamics study of nanoconfined water flow driven by rotating electric fields under realistic experimental conditions.

    PubMed

    De Luca, Sergio; Todd, B D; Hansen, J S; Daivis, Peter J

    2014-03-25

    In our recent work, J. Chem. Phys. 2013, 138, 154712, we demonstrated the feasibility of unidirectional pumping of water, exploiting translational-rotational momentum coupling using nonequilibrium molecular dynamics simulations. Flow can be sustained when the fluid is driven out of equilibrium by an external spatially uniform rotating electric field and confined between two planar surfaces exposing different degrees of hydrophobicity. The permanent dipole moment of water follows the rotating field, thus inducing the molecules to spin, and the torque exerted by the field is continuously injected into the fluid, enabling a steady conversion of spin angular momentum into linear momentum. The translational-rotational coupling is a sensitive function of the rotating electric field parameters. In this work, we have found that there exists a small energy dissipation region attainable when the frequency of the rotating electric field matches the inverse of the dielectric relaxation time of water and when its amplitude lies in a range just before dielectric saturation effects take place. In this region, that is, when the frequency lies in a small window of the microwave region around ∼20 GHz and amplitude ∼0.03 V Å(-1), the translational-rotational coupling is most effective, yielding fluid velocities of magnitudes of ∼2 ms(-1) with only moderate fluid heating. In this work, we also confine water to a realistic nanochannel made of graphene giving a hydrophobic surface on one side and β-cristobalite giving a hydrophilic surface on the other, reproducing slip-and-stick velocity boundary conditions, respectively. This enables us to demonstrate that in a realistic environment, the coupling can be effectively exploited to achieve noncontact pumping of water at the nanoscale. A quantitative comparison between nonequilibrium molecular dynamics and analytical solutions of the extended Navier-Stokes equations, including an external rotating electric field has been performed

  7. Experimental investigation and modeling of uranium (VI) transport under variable chemical conditions

    USGS Publications Warehouse

    Kohler, M.; Curtis, G.P.; Kent, D.B.; Davis, J.A.

    1996-01-01

    The transport of adsorbing and complexing metal ions in porous media was investigated with a series of batch and column experiments and with reactive solute transport modeling. Pulses of solutions containing U(VI) were pumped through columns filled with quartz grains, and the breakthrough of U(VI) was studied as a function of variable solution composition (pH, total U(VI) concentration, total fluoride concentration, and pH-buffering capacity). Decreasing p H and the formation of nonadsorbing aqueous complexes with fluoride increased U(VI) mobility. A transport simulation with surface complexation model (SCM) parameters estimated from batch experiments was able to predict U(VI) retardation in the column experiments within 30%. SCM parameters were also estimated directly from transport data, using the results of three column experiments collected at different pH and U(VI) pulse concentrations. SCM formulations of varying complexity (multiple surface types and reaction stoichiometries) were tested to examine the trade-off between model simplicity and goodness of fit to breakthrough. A two-site model (weak- and strong-binding sites) with three surface complexation reactions fit these transport data well. With this reaction set the model was able to predict (1) the effects of fluoride complexation on U(VI) retardation at two different pH values and (2) the effects of temporal variability of pH on U(VI) transport caused by low p H buffering. The results illustrate the utility of the SCM approach in modeling the transport of adsorbing inorganic solutes under variable chemical conditions.

  8. 1990 Volvo Award in experimental studies. The dependence of intervertebral disc mechanical properties on physiologic conditions.

    PubMed

    Keller, T S; Holm, S H; Hansson, T H; Spengler, D M

    1990-08-01

    In vivo creep-recovery and disc pressure measurements were performed on the lumbar spine of immature and mature swine. The creep-recovery measurements were performed using a custom materials testing apparatus designed to apply static or dynamic loads to the spine of anesthetized animals. A series of three separate experiments were performed to assess the effects of: (I) animal death, (II) graded injury to the disc anulus, and (III) respiratory mechanics on the biomechanical response of the porcine L1-L3 vertebral unit (VU). In Experiments I and II, creep rate, modulus, and viscosity parameters were computed using a three-parameter solid rheological analysis of the displacement-time response recorded during the application of a 300-N load. In Experiment III, the effects of respiratory volume and frequency changes on disc pressure were assessed in the unloaded, statically loaded, and immobilized porcine VU. Our results indicated that the adult VU tended to be stiffer, deform or creep more slowly, and had a significantly higher viscosity than the VU of immature pigs. The results of Experiment I demonstrated that the biomechanical response for the VU was significantly altered by the death of the animal; the VU of the living animal (adolescent or mature) was more compliant and deformed at a faster rate than the VU of the same animal after death. Disc injury produced changes in stiffness, viscosity, and creep rate analogous to that of aging, and on the basis of the graded injuries created in this study, it appears that a small defect in the annulus is just as deleterious as removing a large section of anular material. The results of Experiment III indicated that respiration plays an important role in the normal, in vivo mechanical and nutritional behavior of the porcine VU. Altogether, these results demonstrate that, in the absence of normal physiologic conditions, one may not be able to reliably predict the mechanical response of the lumbar spine, and suggest that

  9. Experimental investigation of a forced response condition in a multistage compressor

    NASA Astrophysics Data System (ADS)

    Murray, William Louis, III

    The objective of this research is twofold. Firstly, the design, development, and construction of a test facility for a Honeywell APU-style centrifugal compressor was implemented, as well as the design and construction of an inlet flow experiment. Secondly, the aeromechanical response of an embedded stage in the Purdue 3-Stage axial research compressor was analyzed through a suite of different measurement techniques in the fulfillment of the end of the GUIde IV Consortium contract. The purpose of the first phase of Honeywell work was to comprehensively measure the flow field of an APU-style centrifugal compressor inlet through the use of Laser Doppler Velocimetry (LDV). A portion of a Honeywell supplied inlet was modified to provide optical access to the elbow, and a gas ejector system was designed and constructed to provide the same suction to the inlet that it would see during operation with the compressor. A performance and health monitoring electronics system was designed and purchased to support the testing of the Honeywell inlet ejector system and eventually it will be used for testing with a centrifugal compressor. Additionally, a secondary air and oil system has been designed and is currently being constructed in the test cell in preparation for the arrival of the Honeywell compressor this summer. An embedded rotor stage in the Purdue 3-stage compressor, with a Campbell diagram crossing of the 1T vibratory mode was analyzed with a suite of measurement systems. In addition to steady state compressor performance measurements, other types of measurements were used to characterize the aerodynamic forcing function for this forced response condition including: NSMS, high-frequency pressure transducers mounted in the casing and in a downstream stator, and cross-film thermal anemometry. Rotor geometry was measured by Aerodyne using an in-situ laser scanning technique. Vibrometry testing was performed at WPAFB to characterize safe operating speeds for stator

  10. Experimental study of the hydrogeochemical properties of the Hontomin cap rock under CO2 supercritical conditions

    NASA Astrophysics Data System (ADS)

    Cama, Jordi; Soler, Josep M.; Davila, Gabriela; Luquot, Linda

    2013-04-01

    Gabriela Dávila, Linda Luquot, Jordi Cama and Josep M. Soler Departament de Geociències, Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), CSIC, Barcelona 08034. The main cap rock for CO2 injection at the PDT Hontomin site (Spain) is a marly shale made up of calcite (56 %), quartz (21%), illite (17%) clinochlore (3%) and others (albite, gypsum, anhydrite, pyrite) (~3%). Contact with CO2-rich acid brines may induce the dissolution of these minerals. Since the brine contains sulfate, gypsum (or anhydrite at depth) may precipitate, which may coat the surface of the dissolving calcite grains and cause their passivation. These mineral reactions will also induce changes in porosity and permeability. Percolation laboratory experiments with Hontomin shale rock cores under controlled pCO2 (8 MPa) are being performed to quantify these processes. In mechanically fractured cores (7.5 mm in diameter and 18 mm in length), two synthetic brines (a sulfate-free solution and a version of the Hontomin formation brine (sulfate solution)) were injected into the rock at constant flow rates (0.2, 1 and 60 mL/h) under CO2 supercritical conditions (pCO2 = 8 MPa and T = 60 °C). As the pH of the injecting brines in equilibrium with a pCO2 of 8 MPa is acidic (~3), it was observed that in the case of the sulfate-free brine experiments, the main processes that yield variation in the hydrodynamic behavior of the fractured rock was the dissolution of calcite, Si-bearing minerals, clinochlore and pyrite. In the sulfate-rich brine experiments, the dissolution of calcite and Si-bearing minerals also occurred, together with gypsum precipitation in the experiments run at low flow rates. As a result, initial fracture permeability tends (i) to stabilize or increase when the cap rock interacts with the sulfate-free brine and (ii) to decrease as the rock interacts with the sulfate-rich brine. The interpretation (reactive transport modeling) of the changes in mineralogy and solution

  11. Experimental testing of total knee replacements with UHMW-PE inserts: impact of severe wear test conditions.

    PubMed

    Zietz, Carmen; Reinders, Joern; Schwiesau, Jens; Paulus, Alexander; Kretzer, Jan Philippe; Grupp, Thomas; Utzschneider, Sandra; Bader, Rainer

    2015-03-01

    Aseptic implant loosening due to inflammatory reactions to wear debris is the main reason for the revision of total knee replacements (TKR). Hence, the decrease in polyethylene wear particle generation from the articulating surfaces is aimed at improving implant design and material. For preclinical testing of new TKR systems standardized wear tests are required. However, these wear tests do not reproduce the entire in vivo situation, since the pattern and amount of wear and subsequent implant failure are underestimated. Therefore, daily activity, kinematics, implant aging and position, third-body-wear and surface properties have to be considered to estimate the wear of implant components in vivo. Hence, severe test conditions are in demand for a better reproduction of the in vivo situation of TKR. In the present article an overview of different experimental wear test scenarios considering clinically relevant polyethylene wear situations using severe test conditions is presented.

  12. SPINE: SParse eIgengene NEtwork linking gene expression clusters in Dehalococcoides mccartyi to perturbations in experimental conditions

    DOE PAGES

    Mansfeldt, Cresten B.; Logsdon, Benjamin A.; Debs, Garrett E.; ...

    2015-02-25

    We present a statistical model designed to identify the effect of experimental perturbations on the aggregate behavior of the transcriptome expressed by the bacterium Dehalococcoides mccartyi strain 195. Strains of Dehalococcoides are used in sub-surface bioremediation applications because they organohalorespire tetrachloroethene and trichloroethene (common chlorinated solvents that contaminate the environment) to non-toxic ethene. However, the biochemical mechanism of this process remains incompletely described. Additionally, the response of Dehalococcoides to stress-inducing conditions that may be encountered at field-sites is not well understood. The constructed statistical model captured the aggregate behavior of gene expression phenotypes by modeling the distinct eigengenes of 100more » transcript clusters, determining stable relationships among these clusters of gene transcripts with a sparse network-inference algorithm, and directly modeling the effect of changes in experimental conditions by constructing networks conditioned on the experimental state. Based on the model predictions, we discovered new response mechanisms for DMC, notably when the bacterium is exposed to solvent toxicity. The network identified a cluster containing thirteen gene transcripts directly connected to the solvent toxicity condition. Transcripts in this cluster include an iron-dependent regulator (DET0096-97) and a methylglyoxal synthase (DET0137). To validate these predictions, additional experiments were performed. Continuously fed cultures were exposed to saturating levels of tetrachloethene, thereby causing solvent toxicity, and transcripts that were predicted to be linked to solvent toxicity were monitored by quantitative reverse-transcription polymerase chain reaction. Twelve hours after being shocked with saturating levels of tetrachloroethene, the control transcripts (encoding for a key hydrogenase and the 16S rRNA) did not significantly change. By contrast, transcripts

  13. Brittle ductile transition in experimentally deformed basalt under oceanic crust conditions

    NASA Astrophysics Data System (ADS)

    Violay, M.; Gibert, B.; Mainprice, D.; Evans, B.; Pezard, P. A.; Flovenz, O.

    2009-04-01

    The mid-ocean ridge system is the largest continuous volcanic feature on Earth, with significant interactions between tectonic activity, volcanism and sea-water circulation. Iceland is the biggest landmass straddling a mid-ocean ridge. The associated tectonic and volcanic settings resulting from the active rifting provide in this geodynamic context a major heat source for the geothermal exploitation. High-pressure, high-temperature, conventional triaxial compression experiments have been conducted in a Paterson Press to explore the brittle-ductile transition of oceanic crustal rocks under in situ conditions at depth (3-10 Km). The study provides some insights into the prospect of producing geothermal fluids from deep wells drilled into a reservoir at temperatures and pressures of supercritical water (T>400°C). We present a series of 20 axial compression deformation experiments performed on jacketed basalt cores of 10 mm diameter and 20 mm long. The experiments were performed at 100 and 300 MPa, with temperatures ranging from 400°C to 900°C, and pore pressures ranging from 0 to 100 MPa, a constant strain rate of 1 × 10- 5 s- 1 and up to strains of 15%. Two different types of basalts were selected for their simple compositions, low alteration degree and very low porosity (3%). The two samples differed in their percentage of glass, being zero in one case and 15% in the other. For the vitreous sample at a confining pressure of 100 and 300 MPa, our experiments show that deformation takes place by three deformation modes; (1) brittle fracture at 400°C with a maximal strength of 900 MPa, corresponding to failure by localized rupture, (2) strain-hardening at small strains and followed by slipping on a localized fracture plane at a constant strength around 250 MPa at higher strains, for temperatures ranging from 500°C to 700°C, (3) distributed ductile flow at differential stresses from 50 to 100 MPa and temperature from 800 to 900°C. For the non glassy sample, the

  14. Nondestructive prediction of point source pyroshock response spectra based on experimental conditioning of laser-induced shocks

    NASA Astrophysics Data System (ADS)

    Jang, Jae-Kyeong; Lee, Jung-Ryul

    2014-09-01

    Pyroshock can easily cause failures in electronic and optical components that are sensitive to high-frequency energy. Pyroshock is generated during explosive-based pyrotechnical events, such as the separation of boosters from a space shuttle and the separation of satellites from a space launcher. Therefore, the prediction of high-frequency structural response, particularly the shock response spectrum (SRS), is important for safe operation of pyrotechnical devices. In general, real explosive testing using distributed accelerometers is widely used. This paper proposes a technology to replace the expensive, dangerous, low-repeatability explosive test with a laser-induced shock test based on a laser beam and in-line filter conditioning. This method does not use any special numerical signal processing. Two different experiments based on explosive and laser excitation were performed with a 2-mm thick aluminum plate. The optimum laser-induced shock experimental conditions to predict real pyroshock were investigated while considering the size, energy, and fluence of the laser beam as parameters. The similarity of the SRS of the laser-induced shock to that of the real explosive pyroshock was evaluated based on the mean acceleration difference (MAD, %). The experimentally determined optimal conditions were also applied to four points on the path of a pyroshock propagation. To match the SRS at each point, the laser-induced shock was amplified, for which three different gain concepts are proposed: the initial gain, optimized gain, and constant gain. The proposed technology enables nondestructive pyro SRS prediction by conditioning the laser-induced shock to obtain an SRS with high similarity to the real pyroshock.

  15. Speech auditory brainstem response (speech ABR) characteristics depending on recording conditions, and hearing status: an experimental parametric study.

    PubMed

    Akhoun, Idrick; Moulin, Annie; Jeanvoine, Arnaud; Ménard, Mikael; Buret, François; Vollaire, Christian; Scorretti, Riccardo; Veuillet, Evelyne; Berger-Vachon, Christian; Collet, Lionel; Thai-Van, Hung

    2008-11-15

    Speech elicited auditory brainstem responses (Speech ABR) have been shown to be an objective measurement of speech processing in the brainstem. Given the simultaneous stimulation and recording, and the similarities between the recording and the speech stimulus envelope, there is a great risk of artefactual recordings. This study sought to systematically investigate the source of artefactual contamination in Speech ABR response. In a first part, we measured the sound level thresholds over which artefactual responses were obtained, for different types of transducers and experimental setup parameters. A watermelon model was used to model the human head susceptibility to electromagnetic artefact. It was found that impedances between the electrodes had a great effect on electromagnetic susceptibility and that the most prominent artefact is due to the transducer's electromagnetic leakage. The only artefact-free condition was obtained with insert-earphones shielded in a Faraday cage linked to common ground. In a second part of the study, using the previously defined artefact-free condition, we recorded speech ABR in unilateral deaf subjects and bilateral normal hearing subjects. In an additional control condition, Speech ABR was recorded with the insert-earphones used to deliver the stimulation, unplugged from the ears, so that the subjects did not perceive the stimulus. No responses were obtained from the deaf ear of unilaterally hearing impaired subjects, nor in the insert-out-of-the-ear condition in all the subjects, showing that Speech ABR reflects the functioning of the auditory pathways.

  16. Radionuclide release from spent fuel under geologic disposal conditions: An overview of experimental and theoretical work through 1985

    SciTech Connect

    Reimus, P.W.; Simonson, S.A.

    1988-04-01

    This report presents an overview of experimental and theoretical work on radionuclide release from spent fuel and uranium dioxide (UO/sub 2/) under geologic disposal conditions. The purpose of the report is to provide a source book of information that can be used to develop models that describe radionuclide release from spent fuel waste packages. Modeling activities of this nature will be conducted within the Waste Package Program (WPP) of the Department of Energy's Salt Repository Project (SRP). The topics discussed include experimental methods for investigating radionuclide release, how results have been reported from radionuclide release experiments, theoretical studies of UO/sub 2/ and actinide solubility, results of experimental studies of radionuclide release from spent fuel and UO/sub 2/ (i.e., the effects of different variables on radionuclide release), characteristics of spent fuel pertinent to radionuclide release, and status of modeling of radionuclide release from spent fuel. Appendix A presents tables of data from spent fuel radionuclide release experiments. These data have been digitized from graphs that appear in the literature. An annotated bibliography of literature on spent fuel characterization is provided in Appendix B.

  17. Experimental study on hydrodynamics of L-type podded propulsor in straight-ahead motion and off-design conditions

    NASA Astrophysics Data System (ADS)

    Zhao, Dagang; Guo, Chunyu; Su, Yumin; Dou, Pengfei; Jing, Tao

    2017-03-01

    Experimental tests were conducted to evaluate the hydrodynamic performance of an L-type podded propulsor in straight-ahead motion and off-design conditions using an open-water measuring instrument developed by the authors for podded propulsors, a ship model towing tank, and under water particle image velocimetry (PIV) measurement systems. Under the three types of conditions, the main parameters of an L-type podded propulsor were measured, including the propeller thrust and torque, as well as the thrust, side force, and moment of the whole pod unit. In addition, the flow field on the section between the propeller and the strut was analyzed. Experimental results demonstrate that the dynamic azimuthing rate and direction and the turning direction affect the forces on the propeller and the whole pod unit. Forces are asymmetrically distributed between the left and right azimuthing directions because of the effect of propeller rotation. The findings of this study provide a foundation for further research on L-type podded propulsors.

  18. Experimental study on hydrodynamics of L-type podded propulsor in straight-ahead motion and off-design conditions

    NASA Astrophysics Data System (ADS)

    Zhao, Dagang; Guo, Chunyu; Su, Yumin; Dou, Pengfei; Jing, Tao

    2017-01-01

    Experimental tests were conducted to evaluate the hydrodynamic performance of an L-type podded propulsor in straight-ahead motion and off-design conditions using an open-water measuring instrument developed by the authors for podded propulsors, a ship model towing tank, and under water particle image velocimetry (PIV) measurement systems. Under the three types of conditions, the main parameters of an L-type podded propulsor were measured, including the propeller thrust and torque, as well as the thrust, side force, and moment of the whole pod unit. In addition, the flow field on the section between the propeller and the strut was analyzed. Experimental results demonstrate that the dynamic azimuthing rate and direction and the turning direction affect the forces on the propeller and the whole pod unit. Forces are asymmetrically distributed between the left and right azimuthing directions because of the effect of propeller rotation. The findings of this study provide a foundation for further research on L-type podded propulsors.

  19. Virulence Differences among Melissococcus plutonius Strains with Different Genetic Backgrounds in Apis mellifera Larvae under an Improved Experimental Condition

    PubMed Central

    Nakamura, Keiko; Yamazaki, Yuko; Shiraishi, Akiyo; Kobayashi, Sota; Harada, Mariko; Yoshiyama, Mikio; Osaki, Makoto; Okura, Masatoshi; Takamatsu, Daisuke

    2016-01-01

    European foulbrood (EFB) caused by Melissococcus plutonius is an important bacterial disease of honeybee larvae. M. plutonius strains can be grouped into three genetically distinct groups (CC3, CC12 and CC13). Because EFB could not be reproduced in artificially reared honeybee larvae by fastidious strains of CC3 and CC13 previously, we investigated a method to improve experimental conditions using a CC3 strain and found that infection with a potassium-rich diet enhanced proliferation of the fastidious strain in larvae at the early stage of infection, leading to the appearance of clear clinical symptoms. Further comparison of M. plutonius virulence under the conditions revealed that the representative strain of CC12 was extremely virulent and killed all tested bees before pupation, whereas the CC3 strain was less virulent than the CC12 strain, and a part of the infected larvae pupated. In contrast, the tested CC13 strain was avirulent, and as with the non-infected control group, most of the infected brood became adult bees, suggesting differences in the insect-level virulence among M. plutonius strains with different genetic backgrounds. These strains and the improved experimental infection method to evaluate their virulence will be useful tools for further elucidation of the pathogenic mechanisms of EFB. PMID:27625313

  20. [The application of the method of radiofrequency myringotomy under the experimental conditions and in the clinical practice].

    PubMed

    Svistushkin, V M; Zolotova, A V; Smirnova, O D; Nikiforova, G N

    2017-01-01

    Exudative otitis media is a widespread pathological condition in the human population. In the recent years, the treatment with the electric current having the frequency up to 3.8 MHz has found the increasingly frequent application, in addition to shunting and laser myringotomy, for the perforation of the tympanic membrane to facilitate removal of exudate. The objective of the present study was to evaluate the effectiveness of the application of the electric current with the frequency up to 4 MHz for myringotomy in the patients presenting with exudative otitis media under the experimental conditions and in the clinical practice. The experimental studies were carried out with the use of the isolated temporal bones (ex vivo) and laboratory animals (in vivo). The clinical studies included the surgical treatment of 41 patients presenting with exudative otitis media using the electric current with the frequency of 4 MHz and laser irradiation with the subsequent evaluation of the inflammatory manifestations in the tympanic membrane tissues during the early post-operative period. It was shown that the method of myringotomy with the application of the electric current having the frequency of 4 MHz is safe and causes no complications. Moreover, it is accompanied by the development of the minimally active inflammatory processes in the tympanic membrane tissues during the early post-operative period.

  1. The influence of simulator input conditions on the wear of total knee replacements: An experimental and computational study

    PubMed Central

    Brockett, Claire L; Abdelgaied, Abdellatif; Haythornthwaite, Tony; Hardaker, Catherine; Fisher, John; Jennings, Louise M

    2016-01-01

    Advancements in knee replacement design, material and sterilisation processes have provided improved clinical results. However, surface wear of the polyethylene leading to osteolysis is still considered the longer-term risk factor. Experimental wear simulation is an established method for evaluating the wear performance of total joint replacements. The aim of this study was to investigate the influence of simulation input conditions, specifically input kinematic magnitudes, waveforms and directions of motion and position of the femoral centre of rotation, on the wear performance of a fixed-bearing total knee replacement through a combined experimental and computational approach. Studies were completed using conventional and moderately cross-linked polyethylene to determine whether the influence of these simulation input conditions varied with material. The position of the femoral centre of rotation and the input kinematics were shown to have a significant influence on the wear rates. Similar trends were shown for both the conventional and moderately cross-linked polyethylene materials, although lower wear rates were found for the moderately cross-linked polyethylene due to the higher level of cross-linking. The most important factor influencing the wear was the position of the relative contact point at the femoral component and tibial insert interface. This was dependent on the combination of input displacement magnitudes, waveforms, direction of motion and femoral centre of rotation. This study provides further evidence that in order to study variables such as design and material in total knee replacement, it is important to carefully control knee simulation conditions. This can be more effectively achieved through the use of displacement control simulation. PMID:27160561

  2. Comparability and Reliability Considerations of Adequate Yearly Progress

    ERIC Educational Resources Information Center

    Maier, Kimberly S.; Maiti, Tapabrata; Dass, Sarat C.; Lim, Chae Young

    2012-01-01

    The purpose of this study is to develop an estimate of Adequate Yearly Progress (AYP) that will allow for reliable and valid comparisons among student subgroups, schools, and districts. A shrinkage-type estimator of AYP using the Bayesian framework is described. Using simulated data, the performance of the Bayes estimator will be compared to…

  3. 13 CFR 107.200 - Adequate capital for Licensees.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... operate actively in accordance with your Articles and within the context of your business plan, as... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Adequate capital for Licensees. 107.200 Section 107.200 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL...

  4. 13 CFR 107.200 - Adequate capital for Licensees.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... operate actively in accordance with your Articles and within the context of your business plan, as... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Adequate capital for Licensees. 107.200 Section 107.200 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL...

  5. Is the Stock of VET Skills Adequate? Assessment Methodologies.

    ERIC Educational Resources Information Center

    Blandy, Richard; Freeland, Brett

    In Australia and elsewhere, four approaches have been used to determine whether stocks of vocational education and training (VET) skills are adequate to meet industry needs. The four methods are as follows: (1) the manpower requirements approach; (2) the international, national, and industry comparisons approach; (3) the labor market analysis…

  6. Do Beginning Teachers Receive Adequate Support from Their Headteachers?

    ERIC Educational Resources Information Center

    Menon, Maria Eliophotou

    2012-01-01

    The article examines the problems faced by beginning teachers in Cyprus and the extent to which headteachers are considered to provide adequate guidance and support to them. Data were collected through interviews with 25 school teachers in Cyprus, who had recently entered teaching (within 1-5 years) in public primary schools. According to the…

  7. 13 CFR 108.200 - Adequate capital for NMVC Companies.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Companies. 108.200 Section 108.200 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM Qualifications for the NMVC Program Capitalizing A Nmvc Company § 108.200 Adequate capital for NMVC Companies. You must meet the requirements of §§ 108.200-108.230 in order...

  8. 13 CFR 108.200 - Adequate capital for NMVC Companies.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Companies. 108.200 Section 108.200 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM Qualifications for the NMVC Program Capitalizing A Nmvc Company § 108.200 Adequate capital for NMVC Companies. You must meet the requirements of §§ 108.200-108.230 in order...

  9. 13 CFR 108.200 - Adequate capital for NMVC Companies.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Companies. 108.200 Section 108.200 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM Qualifications for the NMVC Program Capitalizing A Nmvc Company § 108.200 Adequate capital for NMVC Companies. You must meet the requirements of §§ 108.200-108.230 in order...

  10. 13 CFR 108.200 - Adequate capital for NMVC Companies.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Companies. 108.200 Section 108.200 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM Qualifications for the NMVC Program Capitalizing A Nmvc Company § 108.200 Adequate capital for NMVC Companies. You must meet the requirements of §§ 108.200-108.230 in order...

  11. 13 CFR 108.200 - Adequate capital for NMVC Companies.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Companies. 108.200 Section 108.200 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM Qualifications for the NMVC Program Capitalizing A Nmvc Company § 108.200 Adequate capital for NMVC Companies. You must meet the requirements of §§ 108.200-108.230 in order...

  12. Understanding Your Adequate Yearly Progress (AYP), 2011-2012

    ERIC Educational Resources Information Center

    Missouri Department of Elementary and Secondary Education, 2011

    2011-01-01

    The "No Child Left Behind Act (NCLB) of 2001" requires all schools, districts/local education agencies (LEAs) and states to show that students are making Adequate Yearly Progress (AYP). NCLB requires states to establish targets in the following ways: (1) Annual Proficiency Target; (2) Attendance/Graduation Rates; and (3) Participation…

  13. 34 CFR 200.13 - Adequate yearly progress in general.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 1 2011-07-01 2011-07-01 false Adequate yearly progress in general. 200.13 Section 200.13 Education Regulations of the Offices of the Department of Education OFFICE OF ELEMENTARY AND SECONDARY EDUCATION, DEPARTMENT OF EDUCATION TITLE I-IMPROVING THE ACADEMIC ACHIEVEMENT OF THE...

  14. 34 CFR 200.13 - Adequate yearly progress in general.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 1 2013-07-01 2013-07-01 false Adequate yearly progress in general. 200.13 Section 200.13 Education Regulations of the Offices of the Department of Education OFFICE OF ELEMENTARY AND SECONDARY EDUCATION, DEPARTMENT OF EDUCATION TITLE I-IMPROVING THE ACADEMIC ACHIEVEMENT OF THE...

  15. Region 9: Arizona Adequate Letter (11/1/2001)

    EPA Pesticide Factsheets

    This is a letter from Jack P. Broadbent, Director, Air Division to Nancy Wrona and James Bourney informing them of the adequacy of Revised MAG 1999 Serious Area Carbon Monoxide Plan and that the MAG CO Plan is adequate for Maricopa County.

  16. Experimental reduction of winter food decreases body condition and delays migration in a long-distance migratory bird.

    PubMed

    Cooper, Nathan W; Sherry, Thomas W; Marra, Peter P

    2015-07-01

    Many tropical habitats experience pronounced dry seasons, during which arthropod food availability declines, potentially limiting resident and migratory animal populations. In response to declines in food, individuals may attempt to alter their space use to enhance access to food resources, but may be socially constrained from doing so by con- and heterospecifics. If social constraints exist, food declines should result in decreased body condition. In migratory birds, correlational evidence suggests a link between body condition and migration timing. Poor body condition and delayed migration may, in turn, impact fitness in subsequent seasons via carry-over effects. To determine if winter food availability affects space use, inter- and intraspecific competition, body composition (i.e., mass, fat, and pectoral muscle), and migration timing, we experimentally decreased food availability on individual American Redstart (Setophaga ruticilla) territories in high-quality mangrove habitat. Redstarts on control territories experienced -40% loss of food due to the seasonal nature of the environment. Redstarts on experimental territories experienced -80% declines in food, which closely mimicked natural declines in nearby, low-quality, scrub habitat. Individuals on food-reduced territories did not expand their territories locally, but instead either became non-territorial "floaters" or remained on territory. Regardless of territorial status, food-reduced American Redstarts all deposited fat compared to control birds. Fat deposits provide insurance against the risk of starvation, but, for American Redstarts, came at the expense of maintaining pectoral muscle. Subsequently, food-reduced American Redstarts experienced, on average, a one-week delay in departure on spring migration, likely due to the loss of pectoral muscle. Thus, our results demonstrate experimentally, for the first time, that declines in winter food availability can result in a fat-muscle trade-off, which, in

  17. Plutonium chemistry under conditions relevant for WIPP performance assessment. Review of experimental results and recommendations for future work

    SciTech Connect

    Oversby, Virginia M.

    2000-09-30

    The Waste Isolation Pilot Plant (WIPP), located at a depth of 650 m in bedded salt at a site approximately 40 km east of Carlsbad, New Mexico, was constructed by the US Department of Energy for the disposal of transuranic wastes arising from defense-related activities. The disposal site is regulated by the US Environmental Protection Agency (EPA). During the process leading to certification of the site for initial emplacement of waste, EEG and their contractors reviewed the DOE Compliance Certification Application (CCA) and raised a number of issues. This report reviews the issues related to the chemistry of plutonium as it will affect the potential for release of radioactivity under WIPP conditions. Emphasis is placed on conditions appropriate for the Human Intrusion scenario(s), since human intrusion has the largest potential for releasing radioactivity to the environment under WIPP conditions. The most significant issues that need to be addressed in relation to plutonium chemistry under WIPP conditions are (1) the effects of heterogeneity in the repository on Pu concentrations in brines introduced under the human intrusion scenario, (2) the redox state of Pu in solution and potential for plutonium in solid phases to have a different redox state from that in the solution phase, (3) the effect of organic ligands on the solubility of Pu in WIPP-relevant brines, and (4) the effects of TRU waste characteristics in determining the solubility of Pu. These issues are reviewed with respect to the treatment they received in the DOE CCA, DOE’s response to EEG’s comments on the CCA, and EPA’s response to those comments as reflected in the final EPA rule that led to the opening of the WIPP. Experimental results obtained in DOE’s Actinide Source-Term Test Program (STTP) during the last two years are reviewed and interpreted in the light of other developments in the field of Pu solution chemistry. This analysis is used as the basis for a conceptual model for Pu

  18. Evaporation from Soils Under Thermal Boundary Conditions: Experimental and Modeling Investigation to Compare Equilibrium and Non-Equilibrium Based Approaches

    NASA Astrophysics Data System (ADS)

    Smits, K. M.; Cihan, A.; Sakaki, T.; Illangasekare, T. H.

    2010-12-01

    experimental data. The non-equilibrium approach yielded good agreement with the experimental results, validating the hypothesis that transport in the gas phase is better suited to be modeled with non-equilibrium liquid/gas phase change for highly transient field conditions where the thermal conditions at the land-atmosphere interface are constantly changing. This knowledge is applicable to many current environmental problems to include the simulation of contaminant transport and volatilization in the shallow subsurface and water content fluctuation in the vadose zone interacting with the atmosphere.

  19. Characteristics of the biological cycle of Lutzomyia evandroi Costa Lima & Antunes, 1936 (Diptera: Psychodidae) under experimental conditions.

    PubMed

    de Melo Ximenes, M de F; Maciel, J C; Jerônimo, S M

    2001-08-01

    Lutzomyia evandroi Costa Lima and Antunes, 1936 is found in Rio Grande do Norte, northeastern Brazil, in areas of visceral and mucocutaneous leishmaniasis and follows the same geographic distribution of L. longipalpis. The biological cycle, oviposition, morphological and behavioral characteristics of the species were studied under experimental conditions. The average number of eggs per wild caught female varied from 21 to 50 eggs along the year, with a peak occurring between January and March and another in August, with oviposition lasting for 4 to 12 days. The mean larval phase was 24 days. Ovipositing rates were influenced by rainfall and temperature indexes, with an increase of eggs per oviposition at the beginning and at the end of the rainy season, and a decrease at the peak of the rainy season.

  20. Experimental evidence for growth advantage and metabolic shift stimulated by photophosphorylation of proteorhodopsin expressed in Escherichia coli at anaerobic condition.

    PubMed

    Wang, Ying; Li, Yan; Xu, Tuan; Shi, Zhenyu; Wu, Qiong

    2015-05-01

    Since solar light energy is the source of all renewable biological energy, the direct usage of light energy by bacterial cell factory has been a very attractive concept, especially using light energy to promote anaerobic fermentation growth and even recycle low-energy carbon source when energy is the limiting factor. Proteorhodopsin(PR), a light-driven proton pump proven to couple with ATP synthesis when expressed heterogeneously, is an interesting and simple option to enable light usage in engineered strains. However, although it was reported to influence fermentation in some cases, heterogeneous proteorhodopsin expression was never shown to support growth advantage or cause metabolic shift by photophosphorylation so far. Hereby, we presented the first experimental evidence that heterogeneously expressed proteorhodopsin can provide growth advantage and cause ATP-dependent metabolism shift of acetate and lactate changes in Escherichia coli at anaerobic condition. Those discoveries suggest further application potential of PR in anaerobic fermentation where energy is a limiting factor.

  1. The performance of charcoal-based radon detection under time-varying radon conditions: Experimental and theoretical results

    SciTech Connect

    Sextro, R.G.; Lee, D.D.

    1988-10-01

    Radon adsorption by charcoal is a widely used technique for measuring indoor radon concentration, particularly when short-term results are desired. There are several different devices available, ranging from permeable envelopes filled with charcoal and open-face charcoal-filled canisters to devices incorporating diffusion limiting features to reduce losses of radon due to desorption. However, the integration characteristics of these samplers are not well understood, particularly under conditions of highly varying radon concentrations. A model for predicting the response of various types of charcoal based detectors to time-variant radon concentrations has been developed; the model predictions compare well with results from chamber experiments. Both the experimental and theoretical results have also been compared with integrated continuous-sampling measurements. The implications of these comparisons for use of charcoal for screening measurements is discussed. 5 refs., 4 figs., 2 tabs.

  2. ExpressionData - A public resource of high quality curated datasets representing gene expression across anatomy, development and experimental conditions

    PubMed Central

    2014-01-01

    Reference datasets are often used to compare, interpret or validate experimental data and analytical methods. In the field of gene expression, several reference datasets have been published. Typically, they consist of individual baseline or spike-in experiments carried out in a single laboratory and representing a particular set of conditions. Here, we describe a new type of standardized datasets representative for the spatial and temporal dimensions of gene expression. They result from integrating expression data from a large number of globally normalized and quality controlled public experiments. Expression data is aggregated by anatomical part or stage of development to yield a representative transcriptome for each category. For example, we created a genome-wide expression dataset representing the FDA tissue panel across 35 tissue types. The proposed datasets were created for human and several model organisms and are publicly available at http://www.expressiondata.org. PMID:25228922

  3. Experimental study of physical and chemical melting conditions of rare-metal granites at the Voznesenka ore cluster, Primorye region

    NASA Astrophysics Data System (ADS)

    Aksyuk, A. M.; Konyshev, A. A.; Korzhinskaya, V. S.; Shapovalov, Yu. B.

    2016-09-01

    The melting of two basic granite varieties in the Voznesenka Complex such as Yaroslavka biotite granite and Voznesenka Li-F granite was subject to experimental studies to analyze and to compare the conditions of their physicochemical formation. The experiments were conducted at 550-700°C and 50-500 MPa in pure water and in 0.1 and 1 m HF aqueous fluorine-bearing solutions. The melting temperature of Voznesenka Li-F granites was 60-70°C lower than that of Yaroslavka biotite granites. The temperature decreased by almost 100°C from the completion of biotite granite crystallization to the completion of Li-F granite crystallization.

  4. The Vienna comparative cognition technology (VCCT): an innovative operant conditioning system for various species and experimental procedures.

    PubMed

    Steurer, Michael Morten; Aust, Ulrike; Huber, Ludwig

    2012-12-01

    This article describes a laboratory system for running learning experiments in operant chambers with various species. It is based on a modern version of a classical learning chamber for operant conditioning, the so-called "Skinner box". Rather than constituting a stand-alone unit, as is usually the case, it is an integrated part of a comprehensive technical solution, thereby eliminating a number of practical problems that are frequently encountered in research on animal learning and behavior. The Vienna comparative cognition technology combines modern computer, stimulus presentation, and reinforcement technology with flexibility and user-friendliness, which allows for efficient, widely automatized across-species experimentation, and thus makes the system appropriate for use in a broad range of learning tasks.

  5. Interfacial kinematics and governing mechanisms under the influence of high strain rate impact conditions: Numerical computations of experimental observations

    NASA Astrophysics Data System (ADS)

    Raoelison, R. N.; Sapanathan, T.; Padayodi, E.; Buiron, N.; Rachik, M.

    2016-11-01

    This paper investigates the complex interfacial kinematics and governing mechanisms during high speed impact conditions. A robust numerical modelling technique using Eulerian simulations are used to explain the material response of the interface subjected to a high strain rate collision during a magnetic pulse welding. The capability of this model is demonstrated using the predictions of interfacial kinematics and revealing the governing mechanical behaviours. Numerical predictions of wave formation resulted with the upward or downward jetting and complex interfacial mixing governed by wake and vortex instabilities corroborate the experimental observations. Moreover, the prediction of the material ejection during the simulation explains the experimentally observed deposited particles outside the welded region. Formations of internal cavities along the interface is also closely resemble the resulted confined heating at the vicinity of the interface appeared from those wake and vortex instabilities. These results are key features of this simulation that also explains the potential mechanisms in the defects formation at the interface. These results indicate that the Eulerian computation not only has the advantage of predicting the governing mechanisms, but also it offers a non-destructive approach to identify the interfacial defects in an impact welded joint.

  6. Experimental characterization of initial conditions and spatio-temporal evolution of a small Atwood number Rayleigh-Taylor mixing layer

    SciTech Connect

    Mueschke, N J; Andrews, M J; Schilling, O

    2005-09-26

    The initial multi-mode interfacial velocity and density perturbations present at the onset of a small Atwood number, incompressible, miscible, Rayleigh-Taylor instability-driven mixing layer have been quantified using a combination of experimental techniques. The streamwise interfacial and spanwise interfacial perturbations were measured using high-resolution thermocouples and planar laser-induced fluorescence (PLIF), respectively. The initial multi-mode streamwise velocity perturbations at the two-fluid density interface were measured using particle-image velocimetry (PIV). It was found that the measured initial conditions describe an initially anisotropic state, in which the perturbations in the streamwise and spanwise directions are independent of one another. The evolution of various fluctuating velocity and density statistics, together with velocity and density variance spectra, were measured using PIV and high-resolution thermocouple data. The evolution of the velocity and density statistics is used to investigate the early-time evolution and the onset of strongly-nonlinear, transitional dynamics within the mixing layer. The early-time evolution of the density and vertical velocity variance spectra indicate that velocity fluctuations are the dominant mechanism driving the instability development. The implications of the present experimental measurements on the initialization of Reynolds-averaged turbulent transport and mixing models and of direct and large-eddy simulations of Rayleigh-Taylor instability-induced turbulence are discussed.

  7. Experimental characterization of initial conditions and spatio-temporal evolution of a small Atwood number Rayleigh-Taylor mixing layer

    SciTech Connect

    Mueschke, N J; Andrews, M J; Schilling, O

    2006-03-24

    The initial multi-mode interfacial velocity and density perturbations present at the onset of a small Atwood number, incompressible, miscible, Rayleigh-Taylor instability-driven mixing layer have been quantified using a combination of experimental techniques. The streamwise interfacial and spanwise interfacial perturbations were measured using high-resolution thermocouples and planar laser-induced fluorescence (PLIF), respectively. The initial multi-mode streamwise velocity perturbations at the two-fluid density interface were measured using particle-image velocimetry (PIV). It was found that the measured initial conditions describe an initially anisotropic state, in which the perturbations in the streamwise and spanwise directions are independent of one another. The evolution of various fluctuating velocity and density statistics, together with velocity and density variance spectra, were measured using PIV and high-resolution thermocouple data. The evolution of the velocity and density statistics is used to investigate the early-time evolution and the onset of strongly-nonlinear, transitional dynamics within the mixing layer. The early-time evolution of the density and vertical velocity variance spectra indicate that velocity fluctuations are the dominant mechanism driving the instability development. The implications of the present experimental measurements on the initialization of Reynolds-averaged turbulent transport and mixing models and of direct and large-eddy simulations of Rayleigh-Taylor instability-induced turbulence are discussed.

  8. Experimental evidence of bulk chemistry constraint on SiO2 solubility in clinopyroxene at high-pressure conditions

    NASA Astrophysics Data System (ADS)

    Kawasaki, Toshisuke; Osanai, Yasuhito

    2015-06-01

    We have experimentally confirmed that the solubility of SiO2 in clinopyroxene at ultrahigh-pressure metamorphic conditions is buffered by coesite and kyanite. The present findings were derived from high-pressure experiments on metapelite glass, powdered andesite and eclogite glass under anhydrous conditions. The metapelite glass and powdered andesite were recrystallised in boron nitride capsules at 8 GPa and 1100-1500 °C. The eclogite glass was heated in an AuPd capsule, both ends of which were welded, at 3 GPa and 1000 °C. Clinopyroxene nucleated from metapelite glass, the bulk composition of which is saturated in both SiO2 and Al2SiO5 components plotting within the Jd (Na,K)(Al,Cr)(Si,Ti)2O6-Qtz (Si,Ti)O2-Grt M3(Al,Cr)2(Si,Ti)3O12-Als (Al,Cr)2(Si,Ti)O5 tetrahedron (M = Fe, Mn, Mg, Ni, Zn, Ca), coexists with garnet, coesite and kyanite. The average excess silica content of the clinopyroxene ranges from 23.4 to 35.4 mol%. In contrast, an andesite experiment saturated in SiO2 but undersaturated in Al2SiO5 within the Jd-Qtz-Aug M(Si,Ti)O3-Grt tetrahedron produced clinopyroxene, garnet and coesite but no kyanite. The average excess silica in the clinopyroxene was 9.7-15.5 mol%, which is comparable to previous experimental data. Experiment on the eclogite glass with similar composition to andesite yielded clinopyroxene, garnet and coesite. An average excess silica content in clinopyroxene counts 6.4 mol%, which is much lower than that obtained from the andesite. The SiO2 content of clinopyroxene coexisting with garnet, coesite and kyanite is much higher than that of clinopyroxene coexisting with garnet and coesite without kyanite. Although the temperature dependence is unclear, the SiO2 solubility increases with pressure and Fe/(Fe+Mg). Clinopyroxene forms the solid solution series Jd-Es □0.5M0.5Al(Si,Ti)2O6 and Aug-Es, rather than Jd-Ts MAl2(Si,Ti)O6 and Es-Ts joins. Our experimental data suggest the probable existence of octahedral Si which may accompany the M2

  9. Army General Fund Adjustments Not Adequately Documented or Supported

    DTIC Science & Technology

    2016-07-26

    statements were unreliable and lacked an adequate audit trail. Furthermore, DoD and Army managers could not rely on the data in their accounting...risk that AGF financial statements will be materially misstated and the Army will not achieve audit readiness by the congressionally mandated...and $6.5 trillion in yearend adjustments made to Army General Fund data during FY 2015 financial statement compilation. We conducted this audit in

  10. Hydrolysis of triacetin catalyzed by immobilized lipases: effect of the immobilization protocol and experimental conditions on diacetin yield.

    PubMed

    Hernandez, Karel; Garcia-Verdugo, Eduardo; Porcar, Raul; Fernandez-Lafuente, Roberto

    2011-05-06

    The effect of the immobilization protocol and some experimental conditions (pH value and presence of acetonitrile) on the regioselective hydrolysis of triacetin to diacetin catalyzed by lipases has been studied. Lipase B from Candida antarctica (CALB) and lipase from Rhizomucor miehei (RML) were immobilized on Sepabeads (commercial available macroporous acrylic supports) activated with glutaraldehyde (covalent immobilization) or octadecyl groups (adsorption via interfacial activation). All the biocatalysts accumulated diacetin. Covalently immobilized RML was more active towards rac-methyl mandelate than the adsorbed RML. However, this covalent RML preparation presented the lowest activity towards triacetin. For this reason, this preparation was discarded as biocatalyst for this reaction. At pH 7, acyl migration occurred giving a mixture of 1,2 and 1,3 diacetin, but at pH 5.5, only 1,2 diacetin was produced. Yields were improved at acidic pH values and in the presence of 20% acetonitrile (to over 95%). RML immobilized on octadecyl Sepabeads was proposed as optimal preparation, mainly due to its higher specific activity. Each enzyme preparation presented very different properties. Moreover, changes in the reaction conditions affected the various immobilized enzymes in a different way.

  11. 2,3-Pyridine dicarboxylic acid functionalized gold nanoparticles: Insight into experimental conditions for Cr(3+) sensing.

    PubMed

    Shaikh, Ruqaya; Memon, Najma; Solangi, Amber R; Shaikh, Huma I; Agheem, Muhammad Hassan; Ali, Syed Abid; Shah, Muhammad Raza; Kandhro, Aftab

    2017-02-15

    Selectivity of gold nanoparticles (AuNPs) depends upon surface functionality; small changes in structure or concentration bring significant changes in the behavior of AuNPs. In this study, citrate-capped AuNPs were functionalized with ortho-dicarboxylate substituted pyridine (2,3-PDCA) and detailed studies on experimental conditions were carried out to check the stability of AuNPs and response for Cr(3+). Stability of PDCA-AuNPs was found sensitive to the pH, ionic strength of buffer and its type. Capping behavior of PDCA on C-AuNPs was examined by FTIR spectroscopy. Surface morphology and size of synthesized AuNPs were confirmed by AFM, XRD, and DLS techniques where particles were found 11nm in size, monodisperse and spherical in shape. Interaction of stabilized AuNPs was tested with various metal ions; where Cr(3+) induced the changes in localized surface plasmon band (LSPR) of PDCA-AuNPs which leads to a color change from wine red to violet blue. The phenomenon is explained as cooperative effect of citrate and pyridine nitrogen on surface of AuNPs in contrary to meta-dicarboxylate substituted pyridine derivatives. Further, under optimized and controlled conditions Cr(3+) shows linear response with decrease in absorbance at LSPR intensity of AuNPs (518nm). Moreover, to demonstrate the applicability of method, Cr(3+) was determined in the presence of Cr (VI) which shows 96% recovery.

  12. 2,3-Pyridine dicarboxylic acid functionalized gold nanoparticles: Insight into experimental conditions for Cr3 + sensing

    NASA Astrophysics Data System (ADS)

    Shaikh, Ruqaya; Memon, Najma; Solangi, Amber R.; Shaikh, Huma I.; Agheem, Muhammad Hassan; Ali, Syed Abid; Shah, Muhammad Raza; Kandhro, Aftab

    2017-02-01

    Selectivity of gold nanoparticles (AuNPs) depends upon surface functionality; small changes in structure or concentration bring significant changes in the behavior of AuNPs. In this study, citrate-capped AuNPs were functionalized with ortho-dicarboxylate substituted pyridine (2,3-PDCA) and detailed studies on experimental conditions were carried out to check the stability of AuNPs and response for Cr3 +. Stability of PDCA-AuNPs was found sensitive to the pH, ionic strength of buffer and its type. Capping behavior of PDCA on C-AuNPs was examined by FTIR spectroscopy. Surface morphology and size of synthesized AuNPs were confirmed by AFM, XRD, and DLS techniques where particles were found 11 nm in size, monodisperse and spherical in shape. Interaction of stabilized AuNPs was tested with various metal ions; where Cr3 + induced the changes in localized surface plasmon band (LSPR) of PDCA-AuNPs which leads to a color change from wine red to violet blue. The phenomenon is explained as cooperative effect of citrate and pyridine nitrogen on surface of AuNPs in contrary to meta-dicarboxylate substituted pyridine derivatives. Further, under optimized and controlled conditions Cr3 + shows linear response with decrease in absorbance at LSPR intensity of AuNPs (518 nm). Moreover, to demonstrate the applicability of method, Cr3 + was determined in the presence of Cr (VI) which shows 96% recovery.

  13. Frost characteristics and heat transfer on a flat plate under freezer operating conditions: Part 1, Experimentation and correlations

    SciTech Connect

    Mao, Y.; Besant, R.W.; Chen, H.

    1999-07-01

    An experimental investigation of frost growth on a flat, cold surface supplied by subfreezing, turbulent, humid, parallel flow of air is presented. The operating conditions are typical of many commercial freezers. A test loop was constructed to perform the tests, and the frost height, frost mass concentration, and cold surface heat flux were measured using specially designed and calibrated instrumentation. Twenty tests were done for steady operating conditions, each starting with no initial frost accumulation, and were run for two to six hours giving 480 data samples. Measured results show that the frost characteristics differ significantly with frost growth data taken previously for room temperature airflow. Depending on the temperature of the cold plate and the relative humidity of the subfreezing supply air, the frost could appear to be either smooth or rough. Smooth frost, which occurred at warmer plate temperatures and lower supply air relative humidities, gave rise to frost growth that was much thinner and denser than that for the rough, thick, low-density frost. Frost growth characteristics are correlated as a function of five independent variables (time, distance from the leading edge, cold plate temperature ratio, humidity ratio, and Reynolds number). These correlations are presented separately for the full data set, the rough frost data, and the smooth frost data.

  14. Experimental Investigations of the Effects of Acid Gas (H2S/CO2) Exposure under Geological Sequestration Conditions

    NASA Astrophysics Data System (ADS)

    Hawthorne, S. B.; Miller, D.; Kutchko, B. G.; Strazisar, B. R.

    2009-12-01

    Acid gas (mixed CO2 and H2S) injection into geological formations is increasingly used as a disposal option. In contrast to pure CO2 injection, there is little understanding of the possible effects of acid gases under geological sequestration conditions on exposed materials ranging from reactions with reservoir minerals to the stability of proppants injected to improve oil recovery to the possible failure of well-bore cements. The number of laboratory studies investigating effects of acid gas has been limited by safety concerns and the difficulty in preparing and maintaining single-phase H2S/CO2 mixtures under the experimental pressures and temperatures required. We have developed approaches using conventional syringe pumps and reactor vessels to prepare and maintain H2S/CO2 mixtures under relevant sequestration conditions of temperature, pressure, and exposure to water and dissolved salts. These methods have been used to investigate and compare the effects of acid gas with those of pure CO2 on several materials including reservoir cores, oil recovery proppants, and well-bore cements, as well as to investigate the rates of model reactions such as the conversion of Fe3O4 to pyrite. The apparatus and methods used to perform acid gas exposures and representative results from the various exposed materials will be presented.

  15. [The effect of rubomycin, mexidol and emoxypine on some metabolic indexes and the proccess of spontaneous metastasis under conditions of experimental neoplasia].

    PubMed

    Zor'kina, A V; Prosvirina, O N

    2007-01-01

    The effects of mexidol and emoxypine on some indexes of endotoxicosis and weighted characteristics of tumor carrier during experimental neoplasia have been studied under the conditions of therapy using antracycline antibiotic rubomycin.

  16. Experimental Study of the Influence of the Structure of Local Energy Sources on the Conditions and Characteristics of the Ignition of Liquid Fuels

    NASA Astrophysics Data System (ADS)

    Zakharevich, A. V.; Zygin, M. S.

    2016-11-01

    Experimental studies have been made of the laws of ignition of a group of typical liquid fuels (kerosene, diesel fuel, mazut) by single particles of metals and porous particles of metal oxides heated to high temperatures. We have established the dependences of numerical values of ignition delay times of liquid fuels on the temperature of porous particles formed by welding and of monolithic steel particles in the form of disks. The experimental results show that the delay times of ignition of the typical distillate fuels — kerosene and diesel fuel — by "hot" particles formed by welding metals are shorter than for the ignition of the same fuels by monolithic steel particles of adequate sizes. The ignition delay times of the highly viscous fuel — mazut — are independent of the particle porosity.

  17. Molecular interactions of SO2 with carbonate minerals under co-sequestration conditions: A combined experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Glezakou, Vassiliki-Alexandra; Peter McGrail, B.; Todd Schaef, H.

    2012-09-01

    We present a combined experimental and theoretical study investigating the reactivity between select and morphologically important surfaces of carbonate minerals with supercritical CO2 and co-existing H2O and SO2. Trace amounts of SO2 cause formation of CaSO3 in the form of hannebachite in the initial stages of SO2 adsorption and transformation. Atomistic simulations based on density functional theory of these initial steps indicate accumulation of water over the magnesium sites, and suggest depletion of Mg over the Ca from the mineral surface. Under co-sequestration conditions with wet scCO2, water is not likely to cause carbonate dissolution of a perfect surface, however, it stabilizes pre-existing low coordination oxygen atoms by creating surface hydroxyl groups on the CO2-defect sites. Formation of bisulfites (surface-SO2OH) occurs with a low barrier of ca 0.5 eV, estimated by the climbing image nudged elastic band method (CI-NEB). Estimates of the effective transformation rates are in the range of 4.0 × 101 to 4.0 × 104 s-1. The sulfur-containing species bind preferentially on surface calcium atoms creating the first nucleation sites. Molecular dynamics simulations also show dynamic tautomerization of the adsorbed bifulfites (s-SO2OH ⇌ s-S(H)O3), which is likely to slow down further oxidation to sulfates in less oxidative environments. From the same simulations, we extract local geometries of the resulting CaSO3H···OH species, similar to the crystallographic structure of hannebachite. Collectively, the experimental results and ab initio molecular dynamics simulations suggest potential of carbonate reservoirs for in situ chemical scrubbing of CO2 captured from fossil fuel sources, which could be stored permanently for sequestration purposes or extracted and utilized for enhanced oil recovery (EOR).

  18. Effects of bilateral and unilateral ophthalmectomy on plasma melatonin in Rana tadpoles and froglets under various experimental conditions.

    PubMed

    Wright, Mary L; Francisco, Lucy L; Scott, Jessica L; Richardson, Shaun E; Carr, James A; King, Amy B; Noyes, Arielle G; Visconti, Rachael F

    2006-06-01

    The effect of ophthalmectomy (enucleation) on plasma melatonin in Rana tadpoles and froglets was studied under various experimental conditions to determine if ocular melatonin is released into the circulation from the eyes and to study the factors which might affect this process. Where operations occurred in early or mid-photophase on a 12 light:12 dark (12L:12D) cycle (light onset at 08:00 h), sampling in mid-light and mid-dark revealed that scotophase plasma melatonin was reduced at all developmental stages, with the more significant effects occurring before metamorphic climax. Experiments sampling prometamorphic tadpoles six times in a 24h period on 18L:6D, 12L:12D, or 6L:18D five days after enucleation also showed a significant lowering of plasma melatonin in the dark, so that the scotophase peak was virtually eliminated on all the LD cycles. These findings indicated that the reduction in plasma melatonin after bilateral eye removal was independent of the LD cycle and the metamorphic stage, and that it abolished the diel melatonin rhythm at the expense of the scotophase peak. Experiments carried out for 5 weeks suggested that compensatory secretion of melatonin by other organs after eye removal might partially restore the plasma melatonin level over time. Unilateral ophthalmectomy tended to reduce, but not eliminate, the night peak of plasma melatonin, and did not result in a compensatory increase in ocular melatonin in the remaining eye. Ophthalmectomized tadpoles exhibited darkening of the skin after the operation, which was not associated with a significant change in pituitary alpha-melanotropin. The findings overall indicate that the eyes in Rana tadpoles and froglets contribute up to somewhat over one-half of the circulating melatonin, particularly during the scotophase, and provide experimental evidence for ocular secretion into the blood for the first time in the Amphibia.

  19. Experimental constraints on the differentiation process and pre-eruptive conditions in the magmatic system of Phlegraean Fields (Naples, Italy)

    NASA Astrophysics Data System (ADS)

    Fabbrizio, Alessandro; Carroll, Michael R.

    2008-03-01

    Phase relations of two samples of the Breccia Museo Eruption (BME), BME is an explosive event that took place (about 20 ky ago) during the caldera-forming phase of the Ignimbrite Campana eruption, have been determined experimentally as a function of temperature (700 to 885 °C), pressure (50 to 200 MPa) and water content of the melt. The crystallization experiments were carried out at fO 2 = NNO + 1 log unit. Melt water content ranged from 3.4 to 8 wt.% (H 2O saturation). The synthetic products are compared to the natural phases to constrain the pre-eruptive conditions of trachytic magma in the presence of an H 2O-rich fluid. The major phases occurring in the BME have been reproduced. The stability of biotite is favoured at pressures higher than 135 MPa. Phase equilibria at 200 MPa reproduce the phase assemblage of the magma only at temperatures below 775 °C. Phase abundances and melt fractions indicate that the eruption tapped a magma body that was at a temperature of 780 °C and a pressure in the range 200-140 MPa. The observed major element variations are fully consistent with a fractional crystallization of a sanidine-dominated assemblage starting from the least differentiated trachytes. The compositions of the experimental products are compatible with the progressive tapping of a shallow magma chamber that was chemically zoned. These results suggest that after an early eruptive phase during which the upper, most differentiated level of the magma chamber was tapped, the sudden collapse of the roof of the reservoir triggered drainage of the less evolved remaining magma.

  20. Reference point indentation is insufficient for detecting alterations in traditional mechanical properties of bone under common experimental conditions.

    PubMed

    Krege, John B; Aref, Mohammad W; McNerny, Erin; Wallace, Joseph M; Organ, Jason M; Allen, Matthew R

    2016-06-01

    Reference point indentation (RPI) was developed as a novel method to assess mechanical properties of bone in vivo, yet it remains unclear what aspects of bone dictate changes/differences in RPI-based parameters. The main RPI parameter, indentation distance increase (IDI), has been proposed to be inversely related to the ability of bone to form/tolerate damage. The goal of this work was to explore the relationshipre-intervention RPI measurebetween RPI parameters and traditional mechanical properties under varying experimental conditions (drying and ashing bones to increase brittleness, demineralizing bones and soaking in raloxifene to decrease brittleness). Beams were machined from cadaveric bone, pre-tested with RPI, subjected to experimental manipulation, post-tested with RPI, and then subjected to four-point bending to failure. Drying and ashing significantly reduced RPI's IDI, as well as ultimate load (UL), and energy absorption measured from bending tests. Demineralization increased IDI with minimal change to bending properties. Ex vivo soaking in raloxifene had no effect on IDI but tended to enhance post-yield behavior at the structural level. These data challenge the paradigm of an inverse relationship between IDI and bone toughness, both through correlation analyses and in the individual experiments where divergent patterns of altered IDI and mechanical properties were noted. Based on these results, we conclude that RPI measurements alone, as compared to bending tests, are insufficient to reach conclusions regarding mechanical properties of bone. This proves problematic for the potential clinical use of RPI measurements in determining fracture risk for a single patient, as it is not currently clear that there is an IDI, or even a trend of IDI, that can determine clinically relevant changes in tissue properties that may contribute to whole bone fracture resistance.

  1. Development of an Experimental Data Base to Validate Compressor-Face Boundary Conditions Used in Unsteady Inlet Flow Computations

    NASA Technical Reports Server (NTRS)

    Sajben, Miklos; Freund, Donald D.

    1998-01-01

    The ability to predict the dynamics of integrated inlet/compressor systems is an important part of designing high-speed propulsion systems. The boundaries of the performance envelope are often defined by undesirable transient phenomena in the inlet (unstart, buzz, etc.) in response to disturbances originated either in the engine or in the atmosphere. Stability margins used to compensate for the inability to accurately predict such processes lead to weight and performance penalties, which translate into a reduction in vehicle range. The prediction of transients in an inlet/compressor system requires either the coupling of two complex, unsteady codes (one for the inlet and one for the engine) or else a reliable characterization of the inlet/compressor interface, by specifying a boundary condition. In the context of engineering development programs, only the second option is viable economically. Computations of unsteady inlet flows invariably rely on simple compressor-face boundary conditions (CFBC's). Currently, customary conditions include choked flow, constant static pressure, constant axial velocity, constant Mach number or constant mass flow per unit area. These conditions are straightforward extensions of practices that are valid for and work well with steady inlet flows. Unfortunately, it is not at all likely that any flow property would stay constant during a complex system transient. At the start of this effort, no experimental observation existed that could be used to formulate of verify any of the CFBC'S. This lack of hard information represented a risk for a development program that has been recognized to be unacceptably large. The goal of the present effort was to generate such data. Disturbances reaching the compressor face in flight may have complex spatial structures and temporal histories. Small amplitude disturbances may be decomposed into acoustic, vorticity and entropy contributions that are uncoupled if the undisturbed flow is uniform. This study

  2. Speciation of High-Pressure Carbon-Saturated COH Fluids at Buffered fO2 Conditions: An Experimental Approach

    NASA Astrophysics Data System (ADS)

    Tumiati, S.; Tiraboschi, C.; Recchia, S.; Poli, S.

    2014-12-01

    The quantitative assessment of species in COH fluids is crucial in modelling mantle processes. For instance, H2O/CO2 ratio in the fluid phase influences the location of the solidus and of carbonation/decarbonation reactions in peridotitic systems . In the scientific literature, the speciation of COH fluids has been generally assumed on the basis of thermodynamic calculations using equations of state of simple H2O-non-polar gas systems (e.g., H2O-CO2-CH4). Only few authors dealt with the experimental determination of high-pressure COH fluid species at different conditions, using diverse experimental and analytical approaches (e.g., piston cylinder+capsule-piercing+gas-chromatography/mass-spectrometry; cold-seal+silica glass capsules+Raman). We performed experiments on COH fluids using a capsule-piercing device coupled with a quadrupole mass spectrometry. This type of analyzer ensures superior performances in terms of selectivity of molecules to be detected, high acquisition rates and extended linear response range. Experiments were carried out in a rocking piston cylinder apparatus at pressure of 1 GPa and temperatures from 800 to 900°C. Carbon-saturated fluids were generated through the addition of oxalic acid dihydrate and graphite. Single/double capsules and different packing materials (BN and MgO) were used to evaluate the divergence from the thermodynamic speciation model. Moreover, to assess the effect of solutes on COH fluid speciation we also performed a set of experiments adding synthetic forsterite to the charge. To determine the speciation we assembled a capsule-piercing device that allows to puncture the capsule in a gas-tight vessel at 80°C. The extraction Teflon vessel is composed of a base part, where the capsule is allocated on a steel support, and a top part where a steel drill is mounted. To release the quenched fluids from the capsule, the base part of vessel is hand-tighten to the top part, allowing the steel pointer to pierce the capsule. The

  3. Evaporation from soils under diurnal boundary conditions: Experimental and modeling investigation to evaluate Non-equilibrium-based approaches

    NASA Astrophysics Data System (ADS)

    Trautz, Andrew; Smits, Kathleen; Cihan, Abdullah; Illangasekare, Tissa

    2013-04-01

    Evaporation from bare soil is a key component of the hydrologic cycle and the process primarily responsible for governing water and energy exchanges between the land and atmosphere. Despite its importance, there is still a great deal of uncertainty associated with our current understanding of this complex multiphase phenomenon. A common approach when modeling the movement of liquid water, water vapor and heat in the soil immediately below the land-atmosphere interface is to assume that water vapor concentration in air is always in equilibrium with liquid water. However, this equilibrium assumption is called into question by experiments about liquid/gas phase change in porous media suggesting that the equilibrium establishment is not instantaneous; a volatilization or condensation time is observed at the macroscopic scale under certain conditions. Introduction of such a non-equilibrium mass transfer relationship is based on the Hertz-Knudsen equation (HKE) derived from the kinetic theory of gases. Multiple formulations have been presented to represent the rate of phase change between water and vapor, many relying on empirical fitting parameters due to limited experimental data. The purpose of this work is to perform an unbiased comparison between various conceptual and mathematical formulations for non-equilibrium phase change on evaporation and develop appropriate numerical models to be used in simulations. The key to such a comparison is the availability of accurate data. As such data at the scale of interest is not possible to obtain in field settings, a unique two-dimensional cell apparatus was developed. The test cell was equipped with a network of sensors for automated and continuous monitoring of soil moisture, soil and air temperature and relative humidity, and wind velocity to generate precision data. A fully-coupled numerical model to solve the governing equations for heat, liquid water and water vapor transport in soil was developed. The code implements a

  4. Genetic modification of preimplantation embryos: toward adequate human research policies.

    PubMed

    Dresser, Rebecca

    2004-01-01

    Citing advances in transgenic animal research and setbacks in human trials of somatic cell genetic interventions, some scientists and others want to begin planning for research involving the genetic modification of human embryos. Because this form of genetic modification could affect later-born children and their offspring, the protection of human subjects should be a priority in decisions about whether to proceed with such research. Yet because of gaps in existing federal policies, embryo modification proposals might not receive adequate scientific and ethical scrutiny. This article describes current policy shortcomings and recommends policy actions designed to ensure that the investigational genetic modification of embryos meets accepted standards for research on human subjects.

  5. Elements for adequate informed consent in the surgical context.

    PubMed

    Abaunza, Hernando; Romero, Klaus

    2014-07-01

    Given a history of atrocities and violations of ethical principles, several documents and regulations have been issued by a wide variety of organizations. They aim at ensuring that health care and clinical research adhere to defined ethical principles. A fundamental component was devised to ensure that the individual has been provided the necessary information to make an informed decision regarding health care or participation in clinical research. This article summarizes the history and regulations for informed consent and discusses suggested components for adequate consent forms for daily clinical practice in surgery as well as clinical research.

  6. Efficacy of a new bivalent vaccine of porcine circovirus type 2 and Mycoplasma hyopneumoniae (Fostera™ PCV MH) under experimental conditions.

    PubMed

    Park, Changhoon; Jeong, Jiwoon; Choi, Kyuhyung; Chae, Chanhee

    2016-01-04

    The objective of this study was to evaluate the efficacy of a new bivalent vaccine (Fostera™ PCV MH, Zoetis) of porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae in growing pigs under experimental conditions. A total of 80 pigs were randomly divided into 8 groups (10 pigs per group). The pigs were administered the bivalent vaccine intramuscularly as a 2.0 mL dose at 21 days of age based on the manufacturer's instructions. Three weeks after vaccination, the pigs were inoculated with either PCV2 (intranasal route) or M. hyopneumoniae (intratracheal route) or both. Regardless of the type of inoculation, vaccinated pigs after challenge exhibited effective reduction of clinical signs, PCV2 viremia levels and mycoplasma nasal shedding, and lung and lymphoid lesion when compared to unvaccinated challenged pigs. Vaccinated challenged pigs had significantly higher (P<0.05) levels of PCV2-specific neutralizing antibodies, and numbers of PCV2-and M. hyopneumoniae-specific interferon-γ secreting cells compared to unvaccinated challenged pigs. This study demonstrates that the bivalent vaccine is able to protect pigs against either PCV2 or M. hyopneumoniae infection or both based on clinical, microbiological, immunological, and pathological evaluation.

  7. An experimental investigation of the effect of moisture on the performance of an air-conditioning system

    SciTech Connect

    Goswami, D.Y.; Mathur, G.D.; Gupta, S.; Stoff, L.; Colacino, F.

    1996-12-31

    Tests were conducted at the University of Florida`s Solar Energy and Energy Conversion Laboratory (SEECL) to determine the effect of the moisture on the performance of a 3 ton residential heat pump system with R-22 as the working fluid. The performance of the heat pump system was tested in accordance with the ARI Standard 210/240 (ARI 1989) and ANSI/ASHRAE-37-1988 for testing unitary equipment. ASHRAE`s Air Enthalpy Method was used to determine the performance of heat pump system and ASHRAE`s condition A [Outside 95 F DBT/75 F WBT; Inside 80 F DBT/67 F WBT] was maintained for the tests. The experimental data reveals that moisture levels of approximately 700 ppm in the refrigerant can decrease the system performance by 10--15%. Approximately 50--60% of the moisture injected into the system remains in the refrigerant and the rest mixes with the compressor oil. Hence, it is possible that over a period of time the moisture in the compressor oil may breakdown at the prevailing temperatures and pressures to form acids which may result in catastrophic failure.

  8. Experimental investigations of single-phase and two-phase flow resistance in narrow rectangular duct under rolling condition

    NASA Astrophysics Data System (ADS)

    Xing, Dianchuan; Yan, Changqi; Sun, Licheng; Wang, Yang

    2013-07-01

    Effects of rolling motion on single-phase and two-phase flow resistance were compared experimentally under ambient temperature and pressure. In the single-phase flow experiments, the different pump head was obtained by a variable speed electromotor, and the flow rate was adjusted combining with a regulating valve. However, for the two-phase pressure drop measurements, the pump delivering water operated with an invariable pressure head of 48m, in order to neglect the effect of pump head on flow fluctuation. The results indicated that effects of rolling motion on single-phase flow resistance depend on the pump head. The fluctuation amplitude of flow rate and frictional pressure drop decreases rapidly as the pump head increases, finally, the flow will tend to be steady if the pump head dramatically exceeds the additional pressure drop. Different from the case of single-phase flow, transient frictional pressure drop of two-phase flow fluctuates synchronously with the rolling motion when liquid Reynolds number is less than 1400, whereas keeps a stable steady state without obvious oscillation for other cases. The fluctuation amplitude is independent of rolling period and amplitude and decreases with the increase of flow rate. The inclination angle and phase interface distribution is taken into account in analyzing the influence of rolling motion on two-phase flow resistance. Comparing with the vertical condition, rolling motion nearly has no effects on time-averaged frictional resistance for both the single-phase and two-phase flow.

  9. Resembling a "natural formation pattern" of chlorinated dibenzo-p-dioxins by varying the experimental conditions of hydrothermal carbonization.

    PubMed

    Tirler, Werner; Basso, Albino

    2013-11-01

    Until several years ago dioxins were considered as just an unwanted by product of anthropogenic activities and stigmatized as the symbol of man-made environmental pollution. Natural processes, such as forest fires, can emit dioxins, but compared to industrial processes, usually very low quantities are emitted. However after a case of food contamination occurred in the United States of America in 1996 caused by kaolinitic clay a discussion on the provenience started. Besides the relatively high concentration also an unusual PCDD/F distribution pattern was found in these ball clay samples. This specific pattern related to none of the known anthropogenic sources for these contaminants and, in relation to a supposed natural formation, later it was named "natural formation pattern". Hydrothermal carbonization (HTC) can transform biomass within hours into a brown coal-like product which resembles naturally occurring coal formation. HTC can also transform an already present PCDD/F contamination in a way to obtain a "natural formation pattern" characterized by an unusual high ratio between 1,2,3,7,8,9-HxCDD and 1,2,3,6,7,8-HxCDD and the absence of almost all chlorinated dibenzofurans. By varying the experimental conditions of the HTC process applied to sewage sludge samples contaminated with PCDD/Fs from anthropogenic sources, beside the "natural formation pattern" at a temperatures of 255 °C, a remarkable increase of the toxicity based on WHO-TEQ was observed.

  10. Simultaneous production of nisin and lactic acid from cheese whey: optimization of fermentation conditions through statistically based experimental designs.

    PubMed

    Liu, Chuanbin; Liu, Yan; Liao, Wei; Wen, Zhiyou; Chen, Shulin

    2004-01-01

    A biorefinery process that utilizes cheese whey as substrate to simultaneously produce nisin, a natural food preservative, and lactic acid, a raw material for biopolymer production, was studied. The conditions for nisin biosynthesis and lactic acid coproduction by Lactococcus lactis subsp. lactis (ATCC 11454) in a whey-based medium were optimized using statistically based experimental designs. A Plackett-Burman design was applied to screen seven parameters for significant factors for the production of nisin and lactic acid. Nutrient supplements, including yeast extract, MgSO4, and KH2PO4, were found to be the significant factors affecting nisin and lactic acid formation. As a follow-up, a central-composite design was applied to optimize these factors. Second-order polynomial models were developed to quantify the relationship between nisin and lactic acid production and the variables. The optimal values of these variables were also determined. Finally, a verification experiment was performed to confirm the optimal values that were predicted by the models. The experimented results agreed well with the model prediction, giving a similar production of 19.3 g/L of lactic acid and 92.9 mg/L of nisin.

  11. Optimization of experimental conditions for composite biodiesel production from transesterification of mixed oils of Jatropha and Pongamia

    NASA Astrophysics Data System (ADS)

    Yogish, H.; Chandrashekara, K.; Pramod Kumar, M. R.

    2012-11-01

    India is looking at the renewable alternative sources of energy to reduce its dependence on import of crude oil. As India imports 70 % of the crude oil, the country has been greatly affected by increasing cost and uncertainty. Biodiesel fuel derived by the two step acid transesterification of mixed non-edible oils from Jatropha curcas and Pongamia (karanja) can meet the requirements of diesel fuel in the coming years. In the present study, different proportions of Methanol, Sodium hydroxide, variation of Reaction time, Sulfuric acid and Reaction Temperature were adopted in order to optimize the experimental conditions for maximum biodiesel yield. The preliminary studies revealed that biodiesel yield varied widely in the range of 75-95 % using the laboratory scale reactor. The average yield of 95 % was obtained. The fuel and chemical properties of biodiesel, namely kinematic viscosity, specific gravity, density, flash point, fire point, calorific value, pH, acid value, iodine value, sulfur content, water content, glycerin content and sulfated ash values were found to be within the limits suggested by Bureau of Indian Standards (BIS 15607: 2005). The optimum combination of Methanol, Sodium hydroxide, Sulfuric acid, Reaction Time and Reaction Temperature are established.

  12. Estimation of the neuromotor system functional state after sciatic nerve neurorrhaphy in experimental conditions of intravenous laser irradiation of blood

    NASA Astrophysics Data System (ADS)

    Nechipurenko, N. I.; Tanin, Leonid V.; Antonov, Ignatii P.; Vasilevskaya, Lyudmila A.; Vlasyuk, P. A.

    1996-12-01

    The speckle-optical methods and the methods of electroneuromyography were used to study the myotonus, the contractional activity of leg muscles and the neuromotor system functional state in intact rabbits and 3 months after the sciatic nerve (SN) neurorrhaphy in conditions of intravenous laser irradiation of blood (ILIB). The blood of animals was exposed to laser radiation with the help of a quartz-polymeric light guide, which has been inserted into the earvein the next day after SN stitching. The radiation power at the light guide output was 2-2.5 mW. Two courses of treatment with a two-week interval have been conducted. It has been established from the speckle-optical study data that ILIB increases the contractional activity of skeletal muscles in animals. The ILIB-therapy after the SN neurorrhaphy normalizes the latent period of M-response and neural cation potential. A tendancy has been revealed to an increase in impulse conduction velocity in motor nerve fibers and in maximal amplitude of the neural action potential. Thus, the ILIB-therapy after SN trauma improves the neuromotor system functional state in experimental animals in the early reinnervation period.

  13. Temporal dynamics of 'HoBi'-like pestivirus quasispecies in persistently infected calves generated under experimental conditions.

    PubMed

    Weber, Matheus N; Bauermann, Fernando V; Canal, Cláudio W; Bayles, Darrell O; Neill, John D; Ridpath, Julia F

    2017-01-02

    'HoBi'-like virus is an atypical group within the Pestivirus genus that is implicated in economic losses for cattle producers due to both acute and persistent infections. Pestivirus strains exist as quasispecies (swarms of individual viruses) in infected animals and the viral populations making up the quasispecies differ widely in size and diversity in each animal. In the present study the viral quasispecies circulating in persistently infected (PI) calves, generated and maintained under experimental conditions using two different 'HoBi'-like strains, was observed over time. An increase in genetic variability and the development of certain mutations was observed over time. Mutations observed included the loss of a putative N-linked glycosylation site in the E2 region and the change of specific residues in E1/E2. It is hypothesized that these changes may be the results on continued adaption of the pestivirus to individual hosts. This is the first study characterizing variation in the viral swarms of animals persistently infected with HoBi-like viruses over time. Studies of the shifts in PI viral swarms will contribute to our understanding of the host and viral mechanisms that function in the maintenance of pestivirus persistent infections.

  14. Combining Experimental Petrology and 3D Imaging to Gain Insight into Syn-eruptive Conditions of the Bishop Tuff, California

    NASA Astrophysics Data System (ADS)

    Chattin, Archer; Pamukcu, Ayla; Gardner, James; Gualda, Guilherme

    2015-04-01

    The Bishop tuff is a rhyolitic ignimbrite deposited by a supereruption 0.76 million years ago that formed the Long Valley Caldera in California, USA. Pamukcu et. al (2012) identifies two distinct crystal populations present in the Bishop Tuff, the first being a long-lived, large phenocryst population that records storage conditions, and the second a rapidly nucleated, quickly staunched microlite population thought to result from eruptive decompression. Laboratory experiments to reproduce this quickly grown population may help constrain the conditions and rates under which decompression took place. Rapid nucleation of microlites is accompanied by just as rapid bubble nucleation when volatiles exsolve during decompression; the size distribution of vesicles in eruptive products may thus provide important information on syn-eruptive processes. In this study we combine information from vesicle size distributions on natural pumice with data on experimentally produced microlite crystals with the goal of better understanding the syn-eruptive evolution of a supereruption-forming magma body. Decompression experiments are run using a natural Bishop tuff pumice clast ground and melted in the presence of water to obtain a melt representative of late-erupted Bishop Tuff (LBT) magmas. Experimental charges were subjected to decompression at varying rates and initial temperatures. At this time five experiments have been completed. All decompression experiments start at 130MPa, consistent with water concentration in LBT glass inclusions, and end at 10 MPa. Initial temperatures are either 710°C or 785°C, while decompression rates are 20 MPa/hr, 5.5MPa/hr, or 1.7MPa/hr Experimental products were compared to natural products using Scanning Electron Microscopy to document eventual crystal rims and microlites. We have been successful in causing limited feldspar crystallization, but have yet to generate quartz microlites. Bubble size distributions are obtained by analyzing x

  15. Quantifying dose to the reconstructed breast: Can we adequately treat?

    SciTech Connect

    Chung, Eugene; Marsh, Robin B.; Griffith, Kent A.; Moran, Jean M.; Pierce, Lori J.

    2013-04-01

    To evaluate how immediate reconstruction (IR) impacts postmastectomy radiotherapy (PMRT) dose distributions to the reconstructed breast (RB), internal mammary nodes (IMN), heart, and lungs using quantifiable dosimetric end points. 3D conformal plans were developed for 20 IR patients, 10 autologous reconstruction (AR), and 10 expander-implant (EI) reconstruction. For each reconstruction type, 5 right- and 5 left-sided reconstructions were selected. Two plans were created for each patient, 1 with RB coverage alone and 1 with RB + IMN coverage. Left-sided EI plans without IMN coverage had higher heart Dmean than left-sided AR plans (2.97 and 0.84 Gy, p = 0.03). Otherwise, results did not vary by reconstruction type and all remaining metrics were evaluated using a combined AR and EI dataset. RB coverage was adequate regardless of laterality or IMN coverage (Dmean 50.61 Gy, D95 45.76 Gy). When included, IMN Dmean and D95 were 49.57 and 40.96 Gy, respectively. Mean heart doses increased with left-sided treatment plans and IMN inclusion. Right-sided treatment plans and IMN inclusion increased mean lung V{sub 20}. Using standard field arrangements and 3D planning, we observed excellent coverage of the RB and IMN, regardless of laterality or reconstruction type. Our results demonstrate that adequate doses can be delivered to the RB with or without IMN coverage.

  16. Experimental Study of Abiotic Organic Synthesis at High Temperature and Pressure Conditions: Carbon Isotope and Mineral Surface Characterizations

    NASA Astrophysics Data System (ADS)

    Fu, Q.; Socki, R. A.; Niles, P. B.

    2010-12-01

    Abiotic organic synthesis processes have been proposed as potential mechanisms for methane generation in subseafloor hydrothermal systems on Earth, and on other planets. To better understand the detailed reaction pathways and carbon isotope fractionations in this process under a wide range of physical and chemical conditions, hydrothermal experiments at high temperature (750 °C) and pressure (0.55 GPa) were performed using piston cylinder apparatus. Formic acid was used as the source of CO2 and H2, and magnetite was the mineral catalyst. The chemical and carbon isotopic compositions of dissolved organic products were determined by GC-C-MS-IRMS, while organic intermediaries on the mineral catalyst were characterized by Pyrolysis-GC-MS. Among experimental products, dissolved CO2 was the dominant carbon species with a relative abundance of 88 mol%. Dissolved CH4 and C2H6 were also identified with a mole ratio of CH4 over C2H6 of 15:1. No dissolved CO was detected in the experiment, which might be attributable to the loss of H2 through the Au capsule used in the experiments at high temperature and pressure conditions and corresponding conversion of CO to CO2 by the water-gas shift reaction. Carbon isotope results showed that the δ13C values of CH4 and C2H6 were -50.3‰ and -39.3‰ (V-PDB), respectively. CO2 derived from decarboxylation of formic acid had a δ13C value of -19.2‰, which was 3.2‰ heavier than its source, formic acid. The δ13C difference between CO2 and CH4 was 31.1‰, which was higher than the value of 9.4‰ calculated from theoretical isotopic equilibrium predictions at experimental conditions, suggesting the presence of a kinetic isotope effect. This number was also higher than the values (4.6 to 27.1‰) observed in similar experiments previously performed at 400 °C and 50 MPa with longer reaction times. CH4 is 11.0‰ less enriched in 13C than C2H6. Alcohols were observed as carbon compounds on magnetite surfaces by Pyrolysis-GC-MS, which

  17. Experimental Study of Abiotic Organic Synthesis at High Temperature and Pressure Conditions: Carbon Isotope and Mineral Surface Characterizations

    NASA Technical Reports Server (NTRS)

    Fu, Qi; Socki, R. A.; Niles, P. B.

    2010-01-01

    Abiotic organic synthesis processes have been proposed as potential mechanisms for methane generation in subseafloor hydrothermal systems on Earth, and on other planets. To better understand the detailed reaction pathways and carbon isotope fractionations in this process under a wide range of physical and chemical conditions, hydrothermal experiments at high temperature (750 C) and pressure (0.55 GPa) were performed using piston cylinder apparatus. Formic acid was used as the source of CO2 and H2, and magnetite was the mineral catalyst. The chemical and carbon isotopic compositions of dissolved organic products were determined by GC-C-MS-IRMS, while organic intermediaries on the mineral catalyst were characterized by Pyrolysis-GC-MS. Among experimental products, dissolved CO2 was the dominant carbon species with a relative abundance of 88 mol%. Dissolved CH4 and C2H6 were also identified with a mole ratio of CH4 over C2H6 of 15:1. No dissolved CO was detected in the experiment, which might be attributable to the loss of H2 through the Au capsule used in the experiments at high temperature and pressure conditions and corresponding conversion of CO to CO2 by the water-gas shift reaction. Carbon isotope results showed that the 13C values of CH4 and C2H6 were -50.3% and -39.3% (V-PDB), respectively. CO2 derived from decarboxylation of formic acid had a (sigma)C-13 value of -19.2%, which was 3.2% heavier than its source, formic acid. The (sigma)C-13 difference between CO2 and CH4 was 31.1%, which was higher than the value of 9.4% calculated from theoretical isotopic equilibrium predictions at experimental conditions, suggesting the presence of a kinetic isotope effect. This number was also higher than the values (4.6 to 27.1%) observed in similar experiments previously performed at 400 C and 50 MPa with longer reaction times. CH4 is 11.0% less enriched in C-13 than C2H6. Alcohols were observed as carbon compounds on magnetite surfaces by Pyrolysis-GC-MS, which confirms

  18. Computer synthesis of human motion as a part of an adequate motion analysis experiment

    NASA Astrophysics Data System (ADS)

    Ivanov, Alexandre A.; Sholukha, Victor A.; Zinkovsky, Anatoly V.

    1999-05-01

    The role of problem of computer synthesis of a human motion for a traditional problem of control generalized and muscular forces determination is discussed. It is emphasized significance of computer model choice for adequate analysis kinematic and dynamic experimental data. On the basis of an imitation computer model influence of model's parameters values is demonstrated. With help of non-stationary constraints we can simulate human motions that satisfy to the most significant parameters of the concerned class of motion. Some results of simulation are discussed. We arrive at a conclusion that for correct interpretation of an experiment mixed problem of bodies system dynamics must be solved.

  19. Prostate cancer between prognosis and adequate/proper therapy

    PubMed Central

    Grozescu, T; Popa, F

    2017-01-01

    Knowing the indolent, non-invasive nature of most types of prostate cancer, as well as the simple fact that the disease seems more likely to be associated with age rather than with other factors (50% of men at the age of 50 and 80% at the age of 80 have it [1], with or without presenting any symptom), the big challenge of this clinical entity was to determine severity indicators (so far insufficient) to guide the physician towards an adequate attitude in the clinical setting. The risk of over-diagnosing and over-treating many prostate cancer cases (indicated by all the major European and American studies) is real and poses many question marks. The present paper was meant to deliver new research data and to reset the clinical approach in prostate cancer cases. PMID:28255369

  20. The cerebellopontine angle: does the translabyrinthine approach give adequate access?

    PubMed

    Fagan, P A; Sheehy, J P; Chang, P; Doust, B D; Coakley, D; Atlas, M D

    1998-05-01

    A long-standing but unfounded criticism of the translabyrinthine approach is the misperception that this approach does not give adequate access to the cerebellopontine angle. Because of what is perceived as limited visualization and operating space within the cerebellopontine angle, some surgeons still believe that the translabyrinthine approach is inappropriate for large acoustic tumors. In this study, the surgical access to the cerebellopontine angle by virtue of the translabyrinthine approach is measured and analyzed. The parameters are compared with those measured for the retrosigmoid approach. This series objectively confirms that the translabyrinthine approach offers the neurotologic surgeon a shorter operative depth to the tumor, via a similar-sized craniotomy. This permits superior visualization by virtue of a wider angle of surgical access. Such access is achieved with the merit of minimal cerebellar retraction.

  1. Barriers to adequate prenatal care utilization in American Samoa

    PubMed Central

    Hawley, Nicola L; Brown, Carolyn; Nu’usolia, Ofeira; Ah-Ching, John; Muasau-Howard, Bethel; McGarvey, Stephen T

    2013-01-01

    Objective To describe the utilization of prenatal care in American Samoan women and to identify socio-demographic predictors of inadequate prenatal care utilization. Methods Using data from prenatal clinic records, women (n=692) were categorized according to the Adequacy of Prenatal Care Utilization Index as having received adequate plus, adequate, intermediate or inadequate prenatal care during their pregnancy. Categorical socio-demographic predictors of the timing of initiation of prenatal care (week of gestation) and the adequacy of received services were identified using one way Analysis of Variance (ANOVA) and independent samples t-tests. Results Between 2001 and 2008 85.4% of women received inadequate prenatal care. Parity (P=0.02), maternal unemployment (P=0.03), and both parents being unemployed (P=0.03) were negatively associated with the timing of prenatal care initation. Giving birth in 2007–2008, after a prenatal care incentive scheme had been introduced in the major hospital, was associated with earlier initiation of prenatal care (20.75 versus 25.12 weeks; P<0.01) and improved adequacy of received services (95.04% versus 83.8%; P=0.02). Conclusion The poor prenatal care utilization in American Samoa is a major concern. Improving healthcare accessibility will be key in encouraging women to attend prenatal care. The significant improvements in the adequacy of prenatal care seen in 2007–2008 suggest that the prenatal care incentive program implemented in 2006 may be a very positive step toward addressing issues of prenatal care utilization in this population. PMID:24045912

  2. Toward calculations of the 129Xe chemical shift in Xe@C60 at experimental conditions: relativity, correlation, and dynamics.

    PubMed

    Straka, Michal; Lantto, Perttu; Vaara, Juha

    2008-03-27

    We calculate the 129Xe chemical shift in endohedral Xe@C60 with systematic inclusion of the contributing physical effects to model the real experimental conditions. These are relativistic effects, electron correlation, the temperature-dependent dynamics, and solvent effects. The ultimate task is to obtain the right result for the right reason and to develop a physically justified methodological model for calculations and simulations of endohedral Xe fullerenes and other confined Xe systems. We use the smaller Xe...C6H6 model to calibrate density functional theory approaches against accurate correlated wave function methods. Relativistic effects as well as the coupling of relativity and electron correlation are evaluated using the leading-order Breit-Pauli perturbation theory. The dynamic effects are treated in two ways. In the first approximation, quantum dynamics of the Xe atom in a rigid cage takes advantage of the centrosymmetric potential for Xe within the thermally accessible distance range from the center of the cage. This reduces the problem of obtaining the solution of a diatomic rovibrational problem. In the second approach, first-principles classical molecular dynamics on the density functional potential energy hypersurface is used to produce the dynamical trajectory for the whole system, including the dynamic cage. Snapshots from the trajectory are used for calculations of the dynamic contribution to the absorption 129Xe chemical shift. The calculated nonrelativistic Xe shift is found to be highly sensitive to the optimized molecular structure and to the choice of the exchange-correlation functional. Relativistic and dynamic effects are significant and represent each about 10% of the nonrelativistic static shift at the minimum structure. While the role of the Xe dynamics inside of the rigid cage is negligible, the cage dynamics turns out to be responsible for most of the dynamical correction to the 129Xe shift. Solvent effects evaluated with a polarized

  3. Experimental Study on the pH of Pore water in Compacted Bentonite under Reducing Conditions with Electromigration

    SciTech Connect

    Nessa, S.A.; Idemitsu, K.; Yamazaki, S.; Ikeuchi, H.; Inagaki, Y.; Arima, T.

    2008-07-01

    Compacted bentonite and carbon steel are considered a good buffer and over-pack materials in the repositories of high-level radioactive waste disposal. Sodium bentonite, Kunipia-F contains approximately 95 wt% of montmorillonite. Bentonites prominent properties of high swelling, sealing ability and cation exchange capacity provide retardation against the transport of radionuclides from the waste into the surrounding rocks in the repository and its properties determine the behavior of bentonite. In this regards, the pH of pore water in compacted bentonite is measured with pH test paper wrapped with semi-permeable membrane of collodion sheet under reducing conditions. On 30 days, the pH test paper in the experimental apparatus indicated that the pH of pore water in compacted bentonite is around 8.0 at saturated state. The carbon steel coupon is connected as the working electrode to the potentiostat and is held at a constant supplied potential between +300 and -300 mV vs. Ag/AgCl electrode for up to 7 days. During applying electromigration the pH of pore water in bentonite decreased and it reached 6.0{approx}6.0 on 7 days. The concentration of iron and sodium showed nearly complementary distribution in the bentonite specimen after electromigration. It is expected that iron could migrate as ferrous ion through the interlayer of montmorillonite replacing exchangeable sodium ions in the interlayer. Semi-permeable membrane of collodion sheet does not affect the color change of pH test paper during the experiment. (authors)

  4. Experimental Results of the First Two Stages of an Advanced Transonic Core Compressor Under Isolated and Multi-Stage Conditions

    NASA Technical Reports Server (NTRS)

    Prahst, Patricia S.; Kulkarni, Sameer; Sohn, Ki H.

    2015-01-01

    NASA's Environmentally Responsible Aviation (ERA) Program calls for investigation of the technology barriers associated with improved fuel efficiency of large gas turbine engines. Under ERA the task for a High Pressure Ratio Core Technology program calls for a higher overall pressure ratio of 60 to 70. This mean that the HPC would have to almost double in pressure ratio and keep its high level of efficiency. The challenge is how to match the corrected mass flow rate of the front two supersonic high reaction and high corrected tip speed stages with a total pressure ratio of 3.5. NASA and GE teamed to address this challenge by using the initial geometry of an advanced GE compressor design to meet the requirements of the first 2 stages of the very high pressure ratio core compressor. The rig was configured to run as a 2 stage machine, with Strut and IGV, Rotor 1 and Stator 1 run as independent tests which were then followed by adding the second stage. The goal is to fully understand the stage performances under isolated and multi-stage conditions and fully understand any differences and provide a detailed aerodynamic data set for CFD validation. Full use was made of steady and unsteady measurement methods to isolate fluid dynamics loss source mechanisms due to interaction and endwalls. The paper will present the description of the compressor test article, its predicted performance and operability, and the experimental results for both the single stage and two stage configurations. We focus the detailed measurements on 97 and 100 of design speed at 3 vane setting angles.

  5. EIS Behavior of Experimental High-Strength Steel in Near-Neutral pH and Load Conditions

    NASA Astrophysics Data System (ADS)

    Barraza-Fierro, Jesus Israel; Serna-Barquera, Sergio Alonso; Campillo-Illanes, Bernardo Fabian; Castaneda, Homero

    2017-02-01

    Two thermomechanical heat treatments were applied to a high-strength low carbon steel with an experimental chemical composition, and as a result two different microstructures were obtained. Steel A had a ferritic microstructure, and steel B had a bainitic-martensitic one. The corrosion behavior was reviewed at long times in samples without load by means of Electrochemical Impedance Spectroscopy (EIS) in a near-neutral pH (NNpH) environment. The results showed that the quantity and adherence of corrosion products on the sample surface at long times are different. Hence, the impedance was higher for steel B. Slow strain rate testing (SSRT) was applied to tempered samples of the two steels at 473 K, 673 K, and 873 K (200 °C, 400 °C, and 600 °C), and the corrosion behavior was acquired using EIS at the same time as the SSRT in NNpH conditions. This is a novel result because the tension samples were not electrically isolated from the rest of the load frame. The impedance for the ferritic steel was higher than the bainitic-martensitic one, while it slightly decreased for both steel over time. Tempering improved the corrosion resistance for steel A, while it was not modified for steel B. The corrosion behavior could be associated with the susceptibility of these steels to stress corrosion cracking. A transmission line model was proposed to show qualitatively the corrosion behavior of a crack in the steel, if there is a potential profile inside the crack. A hypothetical potential profile was acquired as well as different impedance behaviors based on electrochemical variables.

  6. EIS Behavior of Experimental High-Strength Steel in Near-Neutral pH and Load Conditions

    NASA Astrophysics Data System (ADS)

    Barraza-Fierro, Jesus Israel; Serna-Barquera, Sergio Alonso; Campillo-Illanes, Bernardo Fabian; Castaneda, Homero

    2017-04-01

    Two thermomechanical heat treatments were applied to a high-strength low carbon steel with an experimental chemical composition, and as a result two different microstructures were obtained. Steel A had a ferritic microstructure, and steel B had a bainitic-martensitic one. The corrosion behavior was reviewed at long times in samples without load by means of Electrochemical Impedance Spectroscopy (EIS) in a near-neutral pH (NNpH) environment. The results showed that the quantity and adherence of corrosion products on the sample surface at long times are different. Hence, the impedance was higher for steel B. Slow strain rate testing (SSRT) was applied to tempered samples of the two steels at 473 K, 673 K, and 873 K (200 °C, 400 °C, and 600 °C), and the corrosion behavior was acquired using EIS at the same time as the SSRT in NNpH conditions. This is a novel result because the tension samples were not electrically isolated from the rest of the load frame. The impedance for the ferritic steel was higher than the bainitic-martensitic one, while it slightly decreased for both steel over time. Tempering improved the corrosion resistance for steel A, while it was not modified for steel B. The corrosion behavior could be associated with the susceptibility of these steels to stress corrosion cracking. A transmission line model was proposed to show qualitatively the corrosion behavior of a crack in the steel, if there is a potential profile inside the crack. A hypothetical potential profile was acquired as well as different impedance behaviors based on electrochemical variables.

  7. Healing of periodontal defects treated with enamel matrix proteins and root surface conditioning--an experimental study in dogs.

    PubMed

    Sakallioğlu, Umur; Açikgöz, Gökhan; Ayas, Bülent; Kirtiloğlu, Tuğrul; Sakallioğlu, Eser

    2004-05-01

    Application of enamel matrix proteins has been introduced as an alternative method for periodontal regenerative therapy. It is claimed that this approach provides periodontal regeneration by a biological approach, i.e. creating a matrix on the root surfaces that promotes cementum, periodontal ligament (PDL) and alveolar bone regeneration, thus mimicking the events occurring during tooth development. Although there have been numerous in vitro and in vivo studies demonstrating periodontal regeneration, acellular cementum formation and clinical outcomes via enamel matrix proteins usage, their effects on the healing pattern of soft and hard periodontal tissues are not well-established and compared with root conditioning alone. In the present study, the effects of Emdogain (Biora, Malmö, Sweden), an enamel matrix derivative mainly composed of enamel matrix proteins (test), on periodontal wound healing were evaluated and compared with root surface conditioning (performed with 36% orthophosphoric acid) alone (control) histopathologically and histomorphometrically by means of the soft and hard tissue profile of periodontium. An experimental periodontitis model performed at premolar teeth of four dogs were used in the study and the healing pattern of periodontal tissues was evaluated at days 7, 14, 21, 28 (one dog at each day), respectively. At day 7, soft tissue attachment evaluated by means of connective tissue and/or epithelial attachment to the root surfaces revealed higher connective tissue attachment rate in the test group and the amount of new connective tissue proliferation in the test group was significantly greater than the control group (p<0.01). New bone formation by osteoconduction initiated at day 14 in the test and control group. At day 21, the orientation of supra-alveolar and PDL fibers established, and new cementum formation observed in both groups. At day 28, although regenerated cementum was cellular in all of the roots in the control samples, an

  8. Experimental determination of trace element mobility in UK North Sea sandstones under conditions of geological CO2 storage

    NASA Astrophysics Data System (ADS)

    Carruthers, Kit; Wilkinson, Mark; Butler, Ian B.

    2016-04-01

    . (1979) and Wigley et al. (2013), to suit the North Sea sandstones used previously in the batch experiments. The extraction method targeted water soluble elements, elements leached through desorption from mineral surfaces, and elements released through the dissolution of carbonates, oxides, sulphides and silicates. From this experimental technique, trace element concentrations were classed as 'mobile' or 'immobile' under weak acid conditions of CO2 storage. The majority of elements were classified as largely immobile. Using the batch experiment results we determined that dissolution of carbonate and feldspar minerals was responsible for much of the observed mobilised concentrations, although the abundance of these minerals was not a predictor for absolute or relative concentrations. References: Tessier, A., Campbell, P. G. C., & Bisson, M. (1979). Sequential Extraction Procedure for the Speciation of Particulate Trace Metals. Analytical Chemistry, 51(7), 844-851. Wigley, M., Kampman, N., Chapman, H. J., Dubacq, B., & Bickle, M. J. (2013). In situ redeposition of trace metals mobilized by CO2-charged brines. Geochemistry, Geophysics, Geosystems, 14(5), 1321-1332. doi:10.1002/ggge.20104

  9. Strength variation and deformational behavior in anisotropic granitic mylonites under high-temperature and -pressure conditions - An experimental study

    NASA Astrophysics Data System (ADS)

    Liu, Gui; Zhou, Yongsheng; Shi, Yaolin; Miao, Sheqiang; He, Changrong

    2017-03-01

    We performed deformation experiments on foliated granitic mylonites under high-temperature and -pressure conditions. To investigate the effects of pre-existing fabric properties on the rheology of the rocks, these experiments were carried out at different compression directions 30°, 45°, and 60° relative to the foliation, at temperatures of 600-850 °C, under confining pressures of 800-1200 MPa, within a strain rate range of 1 × 10-4/S - 2.5 × 10-6/S. The results of the experiments show that the deformation of three group samples is in the semi-brittle region at temperatures between 600 and 700 °C, and that the deformation of the samples transforms to plastic deformation by power-law creep with the stress exponent n = 3 ± 0.3 at temperatures between 800 and 850 °C. In the semi-brittle region, the mechanical data show that strength reaches its minimum value at an angle of 30° between the compression direction and the original foliation. In the plastic deformation regime, strength reaches its minimum value at an angle of 45° between the foliation and the orientation of the maximum principal stress. The strength with angles between 30° and 60° is lower than that of the compression direction perpendicular to foliation and the compression direction parallel to foliation. Microstructure analysis based on optical and electron microscopy of the deformation microstructures showed plastic deformation of aggregates of biotite and quartz at 800-850 °C. This deformation was extensive and formed new foliation. Quartz c-axis fabrics analysis by EBSD show that at temperatures of 600-700 °C, the c-axis fabric patterns could have been formed by the dominant activity of basal slip, similar with the starting granitic mylonite samples, but the dominant slip systems have been changed and transformed from basal slip to rhomb slip and prism slip at temperature of 800 °C and 850 °C. Microfractures were developed in hornblende and feldspar grains with local

  10. Calibrated simulations of Z opacity experiments that reproduce the experimentally measured plasma conditions

    SciTech Connect

    Nagayama, T.; Bailey, J. E.; Loisel, G.; Rochau, G. A.; MacFarlane, J. J.; Golovkin, I.

    2016-02-05

    Recently, frequency-resolved iron opacity measurements at electron temperatures of 170–200 eV and electron densities of (0.7 – 4.0) × 1022 cm–3 revealed a 30–400% disagreement with the calculated opacities [J. E. Bailey et al., Nature (London) 517, 56 (2015)]. The discrepancies have a high impact on astrophysics, atomic physics, and high-energy density physics, and it is important to verify our understanding of the experimental platform with simulations. Reliable simulations are challenging because the temporal and spatial evolution of the source radiation and of the sample plasma are both complex and incompletely diagnosed. In this article, we describe simulations that reproduce the measured temperature and density in recent iron opacity experiments performed at the Sandia National Laboratories Z facility. The time-dependent spectral irradiance at the sample is estimated using the measured time- and space-dependent source radiation distribution, in situ source-to-sample distance measurements, and a three-dimensional (3D) view-factor code. The inferred spectral irradiance is used to drive 1D sample radiation hydrodynamics simulations. The images recorded by slit-imaged space-resolved spectrometers are modeled by solving radiation transport of the source radiation through the sample. We find that the same drive radiation time history successfully reproduces the measured plasma conditions for eight different opacity experiments. These results provide a quantitative physical explanation for the observed dependence of both temperature and density on the sample configuration. Simulated spectral images for the experiments without the FeMg sample show quantitative agreement with the measured spectral images. The agreement in spectral profile, spatial profile, and brightness provides further confidence in our understanding of the backlight-radiation time history and image formation. Furthermore, these simulations bridge the static

  11. Systemic Crisis of Civilization: In Search for Adequate Solution

    NASA Astrophysics Data System (ADS)

    Khozin, Grigori

    In December 1972 a jumbo jet crashed in the Florida Everglades with the loss of 101 lives. The pilot, distracted by a minor malfunction, failed to note until too late the warning signal that - correctly - indicated an impending disaster. His sudden, astonished cry of Hey, what happening here? were his last words 1. Three decades after this tragic episode, as the Humankind approaches the threshold of the third Millennium, the problem of adequate reaction to warning signals of different nature and of distinguishing minor malfunctions in everyday life of society, in economy and technology as well as in evolution of biosphere from grave threats to the world community and the phenomenon of life on our planet remains crucial to human survival and the future of Civilization. Rational use of knowledge and technology available to the world community remains in this context the corner stone of discussions on the destiny of the intelligent life both on the planet Earth and in the Universe (the fact of intelligent life in the Universe is to be detected by the Humankind)…

  12. ENSURING ADEQUATE SAFETY WHEN USING HYDROGEN AS A FUEL

    SciTech Connect

    Coutts, D

    2007-01-22

    Demonstration projects using hydrogen as a fuel are becoming very common. Often these projects rely on project-specific risk evaluations to support project safety decisions. This is necessary because regulations, codes, and standards (hereafter referred to as standards) are just being developed. This paper will review some of the approaches being used in these evolving standards, and techniques which demonstration projects can implement to bridge the gap between current requirements and stakeholder desires. Many of the evolving standards for hydrogen-fuel use performance-based language, which establishes minimum performance and safety objectives, as compared with prescriptive-based language that prescribes specific design solutions. This is being done for several reasons including: (1) concern that establishing specific design solutions too early will stifle invention, (2) sparse performance data necessary to support selection of design approaches, and (3) a risk-adverse public which is unwilling to accept losses that were incurred in developing previous prescriptive design standards. The evolving standards often contain words such as: ''The manufacturer shall implement the measures and provide the information necessary to minimize the risk of endangering a person's safety or health''. This typically implies that the manufacturer or project manager must produce and document an acceptable level of risk. If accomplished using comprehensive and systematic process the demonstration project risk assessment can ease the transition to widespread commercialization. An approach to adequately evaluate and document the safety risk will be presented.

  13. DARHT -- an adequate EIS: A NEPA case study

    SciTech Connect

    Webb, M.D.

    1997-08-01

    In April 1996 the US District Court in Albuquerque ruled that the Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility Environmental Impact Statement (EIS), prepared by the Los Alamos Area Office, US Department of Energy (DOE), was adequate. The DARHT EIS had been prepared in the face of a lawsuit in only 10 months, a third of the time usually allotted for a DOE EIS, and for only a small fraction of the cost of a typical DOE EIS, and for only a small fraction of the cost of a typical DOE EIS. It subject was the first major facility to be built in decades for the DOE nuclear weapons stockpile stewardship program. It was the first EIS to be prepared for a proposal at DOE`s Los Alamos National Laboratory since 1979, and the first ever prepared by the Los Alamos Area Office. Much of the subject matter was classified. The facility had been specially designed to minimize impacts to a nearby prehistoric Native American ruin, and extensive consultation with American Indian Pueblos was required. The week that the draft EIS was published Laboratory biologists identified a previously unknown pair of Mexican spotted owls in the immediate vicinity of the project, bringing into play the consultation requirements of the Endangered Species Act. In spite of these obstacles, the resultant DARHT EIS was reviewed by the court and found to meet all statutory and regulatory requirements; the court praised the treatment of the classified material which served as a basis for the environmental analysis.

  14. Dose Limits for Man do not Adequately Protect the Ecosystem

    SciTech Connect

    Higley, Kathryn A.; Alexakhin, Rudolf M.; McDonald, Joseph C.

    2004-08-01

    It has been known for quite some time that different organisms display differing degrees of sensitivity to the effects of ionizing radiations. Some microorganisms such as the bacterium Micrococcus radiodurans, along with many species of invertebrates, are extremely radio-resistant. Humans might be categorized as being relatively sensitive to radiation, and are a bit more resistant than some pine trees. Therefore, it could be argued that maintaining the dose limits necessary to protect humans will also result in the protection of most other species of flora and fauna. This concept is usually referred to as the anthropocentric approach. In other words, if man is protected then the environment is also adequately protected. The ecocentric approach might be stated as; the health of humans is effectively protected only when the environment is not unduly exposed to radiation. The ICRP is working on new recommendations dealing with the protection of the environment, and this debate should help to highlight a number of relevant issues concerning that topic.

  15. Experimental Control of Nodality via Equal Presentations of Conditional Discriminations in Different Equivalence Protocols under Speed and No-Speed Conditions

    ERIC Educational Resources Information Center

    Imam, Abdulrazaq A.

    2006-01-01

    A within-participant comparison of simple-to-complex, complex-to-simple, and simultaneous protocols was conducted establishing different sets of three 7-member equivalence classes for 4 undergraduate students. The protocols were implemented under either accuracy-only or accuracy-plus-speed conditions while keeping number of presentations of…

  16. MRI can determine the adequate area for debridement in the case of Fournier's gangrene.

    PubMed

    Yoneda, Akira; Fujita, Fumihiko; Tokai, Hirotaka; Ito, Yuichiro; Haraguchi, Masashi; Tajima, Yoshitsugu; Kanematsu, Takashi

    2010-01-01

    A 57-year-old man was transferred to our hospital because of gluteal pain. His right buttock had flare and swelling. Complete blood count showed leukocytosis, and renal failure was evident. Pelvic computed tomography (CT) revealed that the abscess, including gas, was widespread into the hypodermal tissue of the right buttock. Fournier's gangrene had been suspected, and immediate drainage was performed on the right buttock. The symptom and the condition improved rapidly, but on the day after the operation, the patient became drowsy and fell into endotoxic shock. Magnetic resonance imaging (MRI) revealed strong inflammation along the entire fascia of the right femur and necrotizing fasciitis. MRI was very useful for identification of the necrotic range. Immediately, an emergency operation was performed; 3 wide incisions were made on the right thigh and crus for drainage. The patient was cared for intensively under a sedated condition, and irrigation and debridement were repeated every day. Culture of the pus revealed mixed infection of Escherichia coli and anaerobic bacteria, and a large quantity of antimicrobial drug was used. The inflammatory reaction decreased, and the patient's general condition tentatively improved. With Fournier's gangrene, initiating adequate surgical and medical treatment is essential. Therefore, MRI should be used in the early exact diagnosis of this disease to obtain knowledge of the extent of necrosis and to determine the adequate area for debridement.

  17. Experimental results from containment piping bellows subjected to severe accident conditions. Volume 1, Results from bellows tested in `like-new` conditions

    SciTech Connect

    Lambert, L.D.; Parks, M.B.

    1994-09-01

    Bellows are an integral part of the containment pressure boundary in nuclear power plants. They are used at piping penetrations to allow relative movement between piping and the containment wall, while minimizing the load imposed on the piping and wall. Piping bellows are primarily used in steel containments; however, they have received limited use in some concrete (reinforced and prestressed) containments. In a severe accident they may be subjected to pressure and temperature conditions that exceed the design values, along with a combination of axial and lateral deflections. A test program to determine the leak-tight capacity of containment penetration bellows is being conducted under the sponsorship of the US Nuclear Regulatory Commission at Sandia National Laboratories. Several different bellows geometries, representative of actual containment bellows, have been subjected to extreme deflections along with pressure and temperature loads. The bellows geometries and loading conditions are described along with the testing apparatus and procedures. A total of thirteen bellows have been tested, all in the `like-new` condition. (Additional tests are planned of bellows that have been subjected to corrosion.) The tests showed that bellows are capable of withstanding relatively large deformations, up to, or near, the point of full compression or elongation, before developing leakage. The test data is presented and discussed.

  18. [Does sleep apnea disappear once acromegaly is adequately treated?].

    PubMed

    Bruyneel, M; Haumont, S; Devuyst, F

    2016-05-01

    Acromegaly is a rare hormonal disease related to excessive growth hormone secretion. It can result in a range of complications, including cardiovascular, respiratory, metabolic, articular and neoplastic disorders. Among patients with the condition, obstructive sleep apnea syndrome occurs frequently and the effect of treatment is inconstant: improvement, statu quo or deterioration can be observed. We here report three clinical cases, which illustrate the unpredictable evolution of this condition.

  19. On Adequate Comparisons of Antenna Phase Center Variations

    NASA Astrophysics Data System (ADS)

    Schoen, S.; Kersten, T.

    2013-12-01

    One important part for ensuring the high quality of the International GNSS Service's (IGS) products is the collection and publication of receiver - and satellite antenna phase center variations (PCV). The PCV are crucial for global and regional networks, since they introduce a global scale factor of up to 16ppb or changes in the height component with an amount of up to 10cm, respectively. Furthermore, antenna phase center variations are also important for precise orbit determination, navigation and positioning of mobile platforms, like e.g. the GOCE and GRACE gravity missions, or for the accurate Precise Point Positioning (PPP) processing. Using the EUREF Permanent Network (EPN), Baire et al. (2012) showed that individual PCV values have a significant impact on the geodetic positioning. The statements are further supported by studies of Steigenberger et al. (2013) where the impact of PCV for local-ties are analysed. Currently, there are five calibration institutions including the Institut für Erdmessung (IfE) contributing to the IGS PCV file. Different approaches like field calibrations and anechoic chamber measurements are in use. Additionally, the computation and parameterization of the PCV are completely different within the methods. Therefore, every new approach has to pass a benchmark test in order to ensure that variations of PCV values of an identical antenna obtained from different methods are as consistent as possible. Since the number of approaches to obtain these PCV values rises with the number of calibration institutions, there is the necessity for an adequate comparison concept, taking into account not only the numerical values but also stochastic information and computational issues of the determined PCVs. This is of special importance, since the majority of calibrated receiver antennas published by the IGS origin from absolute field calibrations based on the Hannover Concept, Wübbena et al. (2000). In this contribution, a concept for the adequate

  20. Are Vancomycin Trough Concentrations Adequate for Optimal Dosing?

    PubMed Central

    Youn, Gilmer; Jones, Brenda; Jelliffe, Roger W.; Drusano, George L.; Rodvold, Keith A.; Lodise, Thomas P.

    2014-01-01

    The current vancomycin therapeutic guidelines recommend the use of only trough concentrations to manage the dosing of adults with Staphylococcus aureus infections. Both vancomycin efficacy and toxicity are likely to be related to the area under the plasma concentration-time curve (AUC). We assembled richly sampled vancomycin pharmacokinetic data from three studies comprising 47 adults with various levels of renal function. With Pmetrics, the nonparametric population modeling package for R, we compared AUCs estimated from models derived from trough-only and peak-trough depleted versions of the full data set and characterized the relationship between the vancomycin trough concentration and AUC. The trough-only and peak-trough depleted data sets underestimated the true AUCs compared to the full model by a mean (95% confidence interval) of 23% (11 to 33%; P = 0.0001) and 14% (7 to 19%; P < 0.0001), respectively. In contrast, using the full model as a Bayesian prior with trough-only data allowed 97% (93 to 102%; P = 0.23) accurate AUC estimation. On the basis of 5,000 profiles simulated from the full model, among adults with normal renal function and a therapeutic AUC of ≥400 mg · h/liter for an organism for which the vancomycin MIC is 1 mg/liter, approximately 60% are expected to have a trough concentration below the suggested minimum target of 15 mg/liter for serious infections, which could result in needlessly increased doses and a risk of toxicity. Our data indicate that adjustment of vancomycin doses on the basis of trough concentrations without a Bayesian tool results in poor achievement of maximally safe and effective drug exposures in plasma and that many adults can have an adequate vancomycin AUC with a trough concentration of <15 mg/liter. PMID:24165176

  1. Is clinical measurement of anatomic axis of the femur adequate?

    PubMed

    Wu, Chi-Chuan

    2017-03-23

    Background and purpose - The accuracy of using clinical measurement from the anterior superior iliac spine (ASIS) to the center of the knee to determine an anatomic axis of the femur has rarely been studied. A radiographic technique with a full-length standing scanogram (FLSS) was used to assess the adequacy of the clinical measurement. Patients and methods - 100 consecutive young adult patients (mean age 34 (20-40) years) with chronic unilateral lower extremity injuries were studied. The pelvis and intact contralateral lower extremity images in the FLSS were selected for study. The angles between the tibial axis and the femoral shaft anatomic axis (S-AA), the piriformis anatomic axis (P-AA), the clinical anatomic axis (C-AA), and the mechanical axis (MA) were compared between sexes. Results - Only the S-AA and C-AA angles were statistically significantly different in the 100 patients (3.6° vs. 2.8°; p = 0.03). There was a strong correlation between S-AA, P-AA, and C-AA angles (r > 0.9). The average intersecting angle between MA and S-AA in the femur in the 100 patients was 5.5°, and it was 4.8° between MA and C-AA. Interpretation - Clinical measurement of an anatomic axis from the ASIS to the center of the knee may be an adequate and acceptable method to determine lower extremity alignment. The optimal inlet for antegrade femoral intramedullary nailing may be the lateral edge of the piriformis fossa.

  2. Theoretical and experimental methods to select aircraft handling qualities

    NASA Astrophysics Data System (ADS)

    Zaichik, L. E.; Yashin, Y. P.; Perebatov, V. S.; Desyatnik, P. A.

    2013-12-01

    A theoretical-experimental method is developed to analyze and adequately select aircraft handling qualities (HQ). A review is presented of the criteria developed by the authors to estimate the role of motion cues in controlling of an aircraft, and criteria to estimate the on-ground simulation fidelity. The method is presented to translate on-ground simulation results into real flight conditions.

  3. An experimental seasonal hydrological forecasting system over the Yellow River basin - Part 1: Understanding the role of initial hydrological conditions

    NASA Astrophysics Data System (ADS)

    Yuan, Xing; Ma, Feng; Wang, Linying; Zheng, Ziyan; Ma, Zhuguo; Ye, Aizhong; Peng, Shaoming

    2016-06-01

    The hydrological cycle over the Yellow River has been altered by the climate change and human interventions greatly during past decades, with a decadal drying trend mixed with a large variation of seasonal hydrological extremes. To provide support for the adaptation to a changing environment, an experimental seasonal hydrological forecasting system is established over the Yellow River basin. The system draws from a legacy of a global hydrological forecasting system that is able to make use of real-time seasonal climate predictions from North American Multimodel Ensemble (NMME) climate models through a statistical downscaling approach but with a higher resolution and a spatially disaggregated calibration procedure that is based on a newly compiled hydrological observation dataset with 5 decades of naturalized streamflow at 12 mainstream gauges and a newly released meteorological observation dataset including 324 meteorological stations over the Yellow River basin. While the evaluation of the NMME-based seasonal hydrological forecasting will be presented in a companion paper to explore the added values from climate forecast models, this paper investigates the role of initial hydrological conditions (ICs) by carrying out 6-month Ensemble Streamflow Prediction (ESP) and reverse ESP-type simulations for each calendar month during 1982-2010 with the hydrological models in the forecasting system, i.e., a large-scale land surface hydrological model and a global routing model that is regionalized over the Yellow River. In terms of streamflow predictability, the ICs outweigh the meteorological forcings up to 2-5 months during the cold and dry seasons, but the latter prevails over the former in the predictability after the first month during the warm and wet seasons. For the streamflow forecasts initialized at the end of the rainy season, the influence of ICs for lower reaches of the Yellow River can be 5 months longer than that for the upper reaches, while such a difference

  4. Experimental and numerical analyses of finned cross flow heat exchangers efficiency under non-uniform gas inlet flow conditions

    NASA Astrophysics Data System (ADS)

    Bury, Tomasz; Składzień, Jan; Widziewicz, Katarzyna

    2010-10-01

    The work deals with experimental and numerical thermodynamic analyses of cross-flow finned tube heat exchangers of the gas-liquid type. The aim of the work is to determine an impact of the gas non-uniform inlet on the heat exchangers performance. The measurements have been carried out on a special testing rig and own numerical code has been used for numerical simulations. Analysis of the experimental and numerical results has shown that the range of the non-uniform air inlet to the considered heat exchangers may be significant and it can significantly affect the heat exchanger efficiency.

  5. 21 CFR 201.5 - Drugs; adequate directions for use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... because, among other reasons, of omission, in whole or in part, or incorrect specification of: (a... graphic advertising, and conditions, purposes, or uses for which the drug is commonly used; except that... only under the supervision of a practitioner licensed by law and for which it is advertised solely...

  6. Open burning of household waste: Effect of experimental condition on combustion quality and emission of PCDD, PCDF and PCB

    EPA Science Inventory

    Open burning for waste disposal is, in many countries, the dominant source of polychlorinated dibenzodioxins/dibenzofurans and polychlorinated biphenyls (PCDD/PCDF/PCB) release to the environment. To generate emission factors for open burning, experimental pile burns of ca 100 k...

  7. Comparison of experimental and theoretical boundary-layer separation for inlets at incidence angle at low-speed conditions

    NASA Technical Reports Server (NTRS)

    Felderman, E. J.; Albers, J. A.

    1975-01-01

    Comparisons between experimental and theoretical Mach number distributions and separation locations are presented for the internal surfaces of four different subsonic inlet geometries with exit diameters of 13.97 centimeters. The free stream Mach number was held constant at 0.127, the one-dimensional throat Mach number ranged from 0.49 to 0.71, and the incidence angle ranged from 0 deg to 50 deg. Generally good agreement was found between the theoretical and experimental surface Mach number distributions as long as no flow separation existed. At high incidence angles, where separation was obvious in the experimental data, the theory predicted separation on the lip. At lower incidence angles, the theoretical results indicated diffuser separation which was not obvious from the experimental surface Mach number distributions. As incidence angle was varied from 0 deg to 50 deg, the predicted separation location shifted from the diffuser region to the inlet highlight. Relatively small total pressure losses were obtained when the predicted separation location was greater than 0.6 of the distance between the highlight and the diffuser exit.

  8. Analysis of a PEMFC durability test under low humidity conditions and stack behaviour modelling using experimental design techniques

    NASA Astrophysics Data System (ADS)

    Wahdame, Bouchra; Candusso, Denis; Harel, Fabien; François, Xavier; Péra, Marie-Cécile; Hissel, Daniel; Kauffmann, Jean-Marie

    A polymer electrolyte membrane fuel cell (PEMFC) stack has been operated under low humidity conditions during 1000 h. The fuel cell characterisation is based both on polarisation curves and electrochemical impedance spectra recorded for various stoichiometry rates, performed regularly throughout the ageing process. Some design of experiment (DoE) techniques, and in particular the response surface methodology (RSM), are employed to analyse the results of the ageing test and to propose some numerical/statistical laws for the modelling of the stack performance degradation. These mathematical relations are used to optimise the fuel cell operating conditions versus ageing time and to get a deeper understanding of the ageing mechanisms. The test results are compared with those obtained from another stack operated in stationary regime at roughly nominal conditions during 1000 h (reference test). The final objective is to ensure for the next fuel cell systems proper operating conditions leading to extended lifetimes.

  9. Experimental Investigation of a High Head Model Francis Turbine During Steady-State Operation at Off-Design Conditions

    NASA Astrophysics Data System (ADS)

    Bergan, Carl; Goyal, Rahul; Cervantes, Michel J.; Dahlhaug, Ole G.

    2016-11-01

    Francis-99 is a set of workshops aiming to determine the state of the art of high head Francis turbine simulations (flow and structure) under steady and transient operating conditions as well as promote their development and knowledge dissemination openly. The first workshop (Trondheim, 2014) focused on steady state conditions. Some concerns were raised regarding uncertainty in the measurements, mainly that there was no clear vortex rope at the Part Load (PL) condition, and that the flow exhibited relatively large asymmetry. The present paper addresses these concerns in order to ensure the quality of the data presented in further workshops. To answer some of these questions, a new set of measurements were performed on the Francis- 99 model at Waterpower Laboratory at the Norwegian University of Science and Technology (NTNU). In addition to PL, two other operating conditions were considered, for further use in transient measurements, Best Efficiency (BEP) and High Load (HL). The experiments were carried out at a head of 12 m, with a runner rotational speed of 333 revolutions per minute (rpm). The guide vane opening angle were 6.72°, 9.84° and 12.43° for PL, BEP and HL, respectively. The part load condition has been changed from the first workshop, to ensure a fully developed Rotating Vortex Rope (RVR). The velocity and pressure measurements were carried out in the draft tube cone using 2D PIV and six pressure sensors, respectively. The new PL condition shows a fully developed rotating vortex rope (RVR) in both the frequency analysis and in the phase resolved data. In addition, the measurements confirm an asymmetric flow leaving the runner, as was a concern in the first Francis-99 workshop. This asymmetry was detected at both design and off-design conditions, with a stronger effect during off design.

  10. Experimental Evaluation of Inlet Distortion on an Ejector Powered Hybrid Wing Body at Take-off and Landing Conditions

    NASA Technical Reports Server (NTRS)

    Carter, Melissa B.; Shea, Patrick R.; Flamm, Jeffrey D.; Schuh, Michael; James, Kevin D.; Sexton, Matthew R.; Tompkins, Daniel M.; Beyar, Michael D.

    2016-01-01

    As part of the NASA Environmentally Responsible Aircraft project, an ultra high bypass ratio engine integration on a hybrid wing body demonstration was planned. The goal was to include engine and airframe integration concepts that reduced fuel consumption by at least 50% while still reducing noise 42 db cumulative on the ground. Since the engines would be mounted on the upper surface of the aft body of the aircraft, the inlets may be susceptible to vortex ingestion from the wing leading edge at high angles of attack and sideslip, and separated wing/body flow. Consequently, experimental and computational studies were conducted to collect flow surveys useful for characterizing engine operability. The wind tunnel tests were conducted at two NASA facilities, the 14- by 22-foot at NASA Langley and the 40- by 80-foot at NASA Ames Research Center. The test results included in this paper show that the distortion and pressure recovery levels were acceptable for engine operability. The CFD studies conducted to compare to experimental data showed excellent agreement for the angle of attacks examined, although failed to match the low speed experimental data at high sideslip angles.

  11. Precocial rodents as new experimental model to study the effects of altered gravitational conditions on fetal development

    NASA Astrophysics Data System (ADS)

    Sekulić, Slobodan; Božić, Ksenija; Bozić, Aleksandar; Borota, Jelena; Ćulić, Milka

    2006-09-01

    So far the experiments in altered gravitational conditions on the prenatal development have used altricial rodent species. The aim of this study is to explore the differences in the intrauterine development of locomotor system in precocial (guinea pig, spiny mouse) and altricial (rat, mouse, and golden hamster) rodent species and to determine which of these mammalian groups represent a better study model to conduct research on the influence of altered gravitational conditions on human fetal development. Findings suggest that the influence of altered gravitational conditions on development of locomotor system significantly vary according to the maturity of mammals. By the characteristics of maturity at birth precocial rodents are more similar to a human than altricial species. Since precocial species have similar maturity of locomotor system to human, the changes caused by altered gravity among them should be similar as opposed to altricial species.

  12. Adaptive robust image registration approach based on adequately sampling polar transform and weighted angular projection function

    NASA Astrophysics Data System (ADS)

    Wei, Zhao; Tao, Feng; Jun, Wang

    2013-10-01

    An efficient, robust, and accurate approach is developed for image registration, which is especially suitable for large-scale change and arbitrary rotation. It is named the adequately sampling polar transform and weighted angular projection function (ASPT-WAPF). The proposed ASPT model overcomes the oversampling problem of conventional log-polar transform. Additionally, the WAPF presented as the feature descriptor is robust to the alteration in the fovea area of an image, and reduces the computational cost of the following registration process. The experimental results show two major advantages of the proposed method. First, it can register images with high accuracy even when the scale factor is up to 10 and the rotation angle is arbitrary. However, the maximum scaling estimated by the state-of-the-art algorithms is 6. Second, our algorithm is more robust to the size of the sampling region while not decreasing the accuracy of the registration.

  13. Theoretical and Experimental Studies of the Transonic Flow Field and Associated Boundary Conditions near a Longitudinally-Slotted Wind-Tunnel Wall. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Everhart, Joel Lee

    1988-01-01

    A theoretical examination of the slotted-wall flow field is conducted to determine the appropriate wall pressure drop (or boundary condition) equation. This analysis improves the understanding of the fluid physics of these types of flow fields and helps in evaluating the uncertainties and limitations existing in previous mathematical developments. It is shown that the resulting slotted-wall boundary condition contains contributions from the airfoil-induced streamline curvature and the non-linear, quadratic, slot crossflow in addition to an often neglected linear term which results from viscous shearing in the slot. Existing and newly acquired experimental data are examined in the light of this formulation and theoretical developments.

  14. Theoretical and experimental internal flow characteristics of a 13.97-centimeter-diameter inlet at STOL takeoff and approach conditions

    NASA Technical Reports Server (NTRS)

    Albers, J. A.

    1973-01-01

    The theoretical and experimental internal flow characteristics of a 13.97-cm-diam inlet with centerbody retracted and extended are presented at STOL takeoff and approach operating conditions. The theoretical results were obtained from incompressible potential flow corrected for compressibility and boundary layer. Comparisons between theoretical internal surface static-pressure distributions and experimental data are presented for free-stream velocities of 0, 24, 32, and 45 m/sec for a range of inlet incidence angles from 0 to 50 deg. Surface static-pressure distributions are illustrated at circumferential locations of 0, 60, 120, and 180 deg. Surface Mach number distributions from the stagnation point to the diffuser exit are presented along with turbulent boundary-layer shape factors. In general, good agreement was found between the theoretical and experimental surface static pressure distributions.

  15. Analysis of Proliferation of Melanoma Cells and Mesenchymal Stem Cells in Co-Culture and Contribution of Experimental Conditions into Interpretation of the Results.

    PubMed

    Kandarakov, O F; Kopantseva, E E; Belyavsky, A V

    2016-11-01

    A series of experiments on co-culturing of Mel IL melanoma cells and mesenhymal stem cells showed that these cells do not influence proliferation of each other, but we observed weaker adhesion of stromal stem cells to plastic in cocultures where with melanoma cells were grown on mesenhymal stem cells feeder. Cell proliferation was also considerably influenced by experimental conditions, which should be taken into account for correct interpretation of obtained results. The principles of experiments on co-culturing of cancer and stromal cells are formulated that take into account the most important factors influencing cell behavior and minimize the probability of artifact results. It was concluded that co-culturing conditions cells significantly affect the experimental results and can be the source of conflicting conclusions on mutual influence of stromal and cancer cells in vitro.

  16. Experimental comparison of the oxygen-assist laser cutting with a fiber and CO2-laser under the condition of minimal roughness

    NASA Astrophysics Data System (ADS)

    Orishich, A. M.; Shulyatyev, V. B.; Malikov, A. G.; Golyshev, A. A.

    2014-02-01

    The conditions of minimal-roughness surface production were studied experimentally in the process of the oxygenassisted laser cutting with the fiber and СО2 lasers. The coefficient of the laser radiation absorption in the cut channel during the cutting process was measured as the sheet thickness varied from 3 to 16 mm. It is demonstrated that the cutting conditions with the minimal roughness can be formulated for the two laser types with the same generalized parameters, i.e. dimensionless absorbed laser power and Peclet number (dimensionless speed). Numerical values of these parameters were found experimentally. The optimum Peclet number is 0.5 for the СО2-laser cutting, and 0.35 when the fiber laser is used.

  17. Effects of Different Forms of Tutor Action in a Conditional Reasoning Task: An Experimental Approach to the Tutorial Dialogue

    ERIC Educational Resources Information Center

    Olry-Louis. Isabelle

    2009-01-01

    This study investigated how different forms of tutor action influenced novice students' performance on the Wason selection task, and how the students perceived the situation. In the control condition, the tutor provided supportive feedback which was minimal in terms of content (CG), in contrast to help in the form of directives (IM) or questions…

  18. Ontology for Life-Cycle Modeling of Heating, Ventilating, and Air Conditioning (HVAC) Systems: Experimental Applications Using Revit

    DTIC Science & Technology

    2012-03-01

    Center, Construction Engineering Research Laboratory (ERDC-CERL) has developed a core life- cycle building information model ( BIM ) based on three...was to promote consistency and quality of content created for Building Information Models ( BIMs ) across various disciplines. The HVAC MVD was...MVD. 15. SUBJECT TERMS building information modeling ( BIM ), ontology, Army facilities, heating, ventilating, and air-conditioning (HVAC) systems

  19. Experimental study on occupant's thermal responses under the non-uniform conditions in vehicle cabin during the heating period

    NASA Astrophysics Data System (ADS)

    Zhang, Wencan; Chen, Jiqing; Lan, Fengchong

    2014-03-01

    The existing investigations on thermal comfort mostly focus on the thermal environment conditions, especially of the air-flow field and the temperature distributions in vehicle cabin. Less attention appears to direct to the thermal comfort or thermal sensation of occupants, even to the relationship between thermal conditions and thermal sensation. In this paper, a series of experiments were designed and conducted for understanding the non-uniform conditions and the occupant's thermal responses in vehicle cabin during the heating period. To accurately assess the transient temperature distribution in cabin in common daily condition, the air temperature at a number of positions is measured in a full size vehicle cabin under natural winter environment in South China by using a discrete thermocouples network. The occupant body is divided into nine segments, the skin temperature at each segment and the occupant's local thermal sensation at the head, body, upper limb and lower limb are monitored continuously. The skin temperature is observed by using a discrete thermocouples network, and the local thermal sensation is evaluated by using a seven-point thermal comfort survey questionnaire proposed by American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc(ASHRAE) Standard. The relationship between the skin temperature and the thermal sensation is discussed and regressed by statistics method. The results show that the interior air temperature is highly non-uniform over the vehicle cabin. The locations where the occupants sit have a significant effect on the occupant's thermal responses, including the skin temperature and the thermal sensation. The skin temperature and thermal sensation are quite different between body segments due to the effect of non-uniform conditions, clothing resistance, and the human thermal regulating system. A quantitative relationship between the thermal sensation and the skin temperature at each body segment of occupant in

  20. Performance enhancement of an experimental air conditioning system by using TiO2/methanol nanofluid in heat pipe heat exchangers

    NASA Astrophysics Data System (ADS)

    Monirimanesh, Negin; Nowee, S. Mostafa; Khayyami, Shideh; Abrishamchi, Iman

    2016-05-01

    The effect of using nanofluid in thermosyphon-type heat pipe heat exchangers on energy conservation of an air-conditioning system was sought in this study. Innovatively, two heat exchangers in-series were deployed using TiO2/methanol nanofluids with 0-4 wt% concentrations as working fluids. The impacts of temperature and relative humidity on the effectiveness of 2 and 4-row heat exchangers were analyzed experimentally and more that 40 % energy saving was obtained.

  1. [Certain results of the investigations into the anti-tumour action of the magnetic field under experimental conditions].

    PubMed

    Ulashchik, V S

    2015-01-01

    This paper summarizes the results of the application of thr magnetic fields for the treatment of experimental tumours, such as sarcoma M-1, alveolar liver cancer PC-1, and Erlich's carcinoma. The evidence of the anti-tumour action of both strong (1200 mTI) and weak (5 to 100 mTI) magnetic fields has been obtained. The author describes the modulating effect of the magnetic fields on the anti-tumour potency of photodynamic therapy and chemotherapy. The data concerning the impact of ferromagnetic hyperthermal therapy on the tumour growth and the survival rate among the tumour-bearing animals are presented.

  2. Experimental Study on the Influence of the Supporting Condition and Rod Motion on the Fuel Fretting Damage

    SciTech Connect

    Kim, Hyung-Kyu; Lee, Young-Ho

    2007-07-01

    Present study focuses on the influence of a supporting condition and a rod motion on a fuel fretting wear through experiments using a self-developed wear simulator, which was presented at the Water Reactor Fuel Performance Meeting, Kyoto Japan in 2005. In the experiment, a fuel rod specimen of two span lengths is vibrated by two perpendicularly aligned electromagnetic actuators. Both ends of the rod specimen are supported with a positive contact force and a variation of the supporting condition is simulated by moving each of the four grid strap specimens constituting a center grid cell. As for the supporting condition, 0.1 mm gap and 10 N force are used; a circular and a diagonal traces are applied for the rod motion. The contact shape of the spring/dimple is concave, to try and increase the contact area. Both the spring/dimple and fuel rod specimens were fabricated from the as-received materials (zirconium alloy) for a commercial fuel assembly. Experiments are carried out under a room temperature and distilled water condition. Experiment of each condition is carried out for 72 hours. Wear volume, area and depth on the cladding tubes are examined. As a result, the present concave shaped spring/dimple causes less wear when the rod moves in a circular manner than a diagonal one if there is a positive contact force (10 N). However, a diagonal motion causes more wear when a gap (0.1 mm) exists. Wear amount at the spring and dimple is influenced by the location of them and the rod motion. It is found that the wear is concentrated at the contact edges between the spring/dimple and rods due to the contact shape. The influence of the rod motion on the worn area and its shape is also discussed. (authors)

  3. In situ cleaning of diagnostic first mirrors: an experimental comparison between plasma and laser cleaning in ITER-relevant conditions

    NASA Astrophysics Data System (ADS)

    Maffini, A.; Moser, L.; Marot, L.; Steiner, R.; Dellasega, D.; Uccello, A.; Meyer, E.; Passoni, M.

    2017-04-01

    This paper presents an experimental comparison between the plasma cleaning and the laser cleaning techniques of diagnostic first mirrors (FMs). The re-deposition of contaminants sputtered from a tokamak first wall onto FMs could dramatically decrease their reflectance in an unacceptable way for the proper functioning of plasma diagnostic systems. Therefore, suitable in situ cleaning solutions will be required to recover the FMs reflectance in ITER. Currently, plasma cleaning and laser cleaning are considered the most promising solutions. In this work, a set of ITER-like rhodium mirrors contaminated with materials tailored to reproduce tokamak redeposits is employed to experimentally compare plasma and laser cleaning against different criteria (reflectance recovery, mirror integrity, time requirement). We show that the two techniques present different complementary features that can be exploited for the cleaning of ITER FMs. In particular, plasma cleaning ensures an excellent reflectance recovery in the case of compact contaminants, while laser cleaning is faster, gentler, and more effective in the case of porous contaminant. In addition, we demonstrate the potential benefits of a synergistic solution which combines plasma and laser cleaning to exploit the best features of each technique.

  4. Experimental study on the effect of temperature and flux conditions on moisture distribution in vadose zone soil.

    PubMed

    Wang, Jinguo; Zheng, Hu

    2017-02-01

    Moisture distribution in vadose zone soil is the most important parameter for land productivity and vegetation status of ecological systems, and is sensitive to temperature variation. In this study, laboratory scale tests were conducted to determine the effect of temperature on variation in moisture distribution in covered and uncovered conditions. The results indicated that soil moisture from 2.65 to 20 cm was positively correlated with temperature and temperature gradient, and the top 2.65 to 5 cm was dramatically influenced by temperature changes in both covered and uncovered conditions. The moisture content when temperature was increasing was higher than that when temperature was decreasing for the same temperature, when the film covered the top of the soil column. In contrast, the moisture content when temperature was increasing was lower than when the temperature was decreasing for the uncovered soil column. The difference between treatments was not maintained as soil depth increased.

  5. [Comparative evaluation of the neuroprotective activity of phenibut and piracetam under experimental cerebral ischemia conditions in rats].

    PubMed

    Tiurenkov, I N; Bagmetov, M N; Epishina, V V; Borodkina, L E; Voronkov, A V

    2006-01-01

    The neuroprotective properties of phenibut and piracetam were studied in rats with cerebral ischemia caused by bilateral irreversible simultaneous occlusion of carotid arteries and gravitational overload in craniocaudal vector. In addition, the effects of both drugs on microcirculation in brain cortex under ischemic injury conditions were studied. Phenibut and (to a lower extent) piracetam reduced a neuralgic deficiency, amnesia, and the degree of cerebral circulation drop, and improved the spontaneous movement and research activity deteriorated by brain ischemia.

  6. Automated valve condition classification of a reciprocating compressor with seeded faults: experimentation and validation of classification strategy

    NASA Astrophysics Data System (ADS)

    Lin, Yih-Hwang; Liu, Huai-Sheng; Wu, Chung-Yung

    2009-09-01

    This paper deals with automatic valve condition classification of a reciprocating processor with seeded faults. The seeded faults are considered based on observation of valve faults in practice. They include the misplacement of valve and spring plates, incorrect tightness of the bolts for valve cover or valve seat, softening of the spring plate, and cracked or broken spring plate or valve plate. The seeded faults represent various stages of machine health condition and it is crucial to be able to correctly classify the conditions so that preventative maintenance can be performed before catastrophic breakdown of the compressor occurs. Considering the non-stationary characteristics of the system, time-frequency analysis techniques are applied to obtain the vibration spectrum as time develops. A data reduction algorithm is subsequently employed to extract the fault features from the formidable amount of time-frequency data and finally the probabilistic neural network is utilized to automate the classification process without the intervention of human experts. This study shows that the use of modification indices, as opposed to the original indices, greatly reduces the classification error, from about 80% down to about 20% misclassification for the 15 fault cases. Correct condition classification can be further enhanced if the use of similar fault cases is avoided. It is shown that 6.67% classification error is achievable when using the short-time Fourier transform and the mean variation method for the case of seven seeded faults with 10 training samples used. A stunning 100% correct classification can even be realized when the neural network is well trained with 30 training samples being used.

  7. Do we teach earth science in situ adequately?

    NASA Astrophysics Data System (ADS)

    Rakhmenkulova, I.; Zhitov, E.; Zhitova, L.

    2006-12-01

    The Russian education system for future earth scientists inherited many good features from ex-Soviet times. Some schools even have unique conditions for teaching earth sciences, both in general, and in situ. For example, at the Department of Geology and Geophysics (DGG) of Novosibirsk State University (NSU) students apart from traditional academic geoscience field excursions are supposed to participate in real scientific expeditions, and the materials they get as the result are actually the basis of their course papers, diploma thesis, and PhD thesis. This is possible because Novosibirsk State University works in close connection with scientific institutions (the Institute of Geology and Mineralogy, the Institute of Oil and Gas Geophysics and others), and most instructors, professors and lecturers are from these institutions. There are five traditional field trips for DGG students of NSU: 1. Geology field trip at the Altay mountain region, a place of unique geological conditions and beautiful nature. 2. Geodesy field work in Academgorodok ( 30km from Novosibirsk). 3. Field trip in structural geology in Khakassia (Shira, the southern part of the Krasnoyarsk region, Siberia) (NSU has its own field camp there). 4. Geophysics field work in Burmistrovo (NSU has its own field camp there). 5. Mineralogy field trip in Tuva (Siberia). Besides the above mentioned field trips (being the academic part DGG education) each student is supposed to participate in at least one real scientific field trip for BsD, in two trips for MsD and much more for PhD. These field trips are chosen by students and the geography of these trips covers Siberia, Far East, Kamchatka, Sahkalin, and even foreign countries (Mongolia, China, etc). The students pay neither for their academic education, not for their later field trips; on the contrary, they get money for their work in real scientific field trips. However, there are many problems the Russian education system and universities face these days

  8. Control of experimental Triatoma infestans populations: effect of pour-on cypermethrin applied to chickens under natural conditions in the Argentinean Chaco region.

    PubMed

    Amelotti, I; Catalá, S S; Gorla, D E

    2014-06-01

    Among peridomestic structures, chicken coops are sites of major importance for the domestic ecology of Triatoma infestans (Hemiptera: Reduviidae). The aim of this study was to evaluate in an experimental context the effects of a cypermethrin pour-on formulation applied to chickens on blood intake, moulting and mortality in T. infestans, under the natural climatic conditions of a region endemic for Chagas' disease. Experimental chicken huts were made of bricks and covered with plastic mosquito nets. Ninety fourth-instar nymphs were maintained in each hut. The study used a completely random design in which chickens in the experimental group were treated with a cypermethrin pour-on formulation. Five replicates (= huts) of the experimental and control groups were conducted. The number of live T. infestans, blood intake and moults to fifth-instar stage were recorded at 1, 5, 20, 35 and 45 days after the application of cypermethrin. Cumulative mortality was higher in nymphs exposed to treated chickens (> 71%) than in control nymphs (< 50%) (P < 0.01). Blood intake and moulting rate were lower in nymphs fed on treated chickens than in control nymphs (P < 0.05). Pour-on cypermethrin was able to cause significant mortality, although it did not eliminate the experimental population of T. infestans.

  9. Communities of different plant diversity respond similarly to drought stress: experimental evidence from field non-weeded and greenhouse conditions.

    PubMed

    Lanta, Vojtěch; Doležal, Jiří; Zemková, Lenka; Lepš, Jan

    2012-06-01

    Accelerating rate of species loss has prompted researchers to study the role of species diversity in processes that control ecosystem functioning. Although negative impact of species loss has been documented, the evidence concerning its impact on ecosystem stability is still limited. Here, we studied the effects of declining species and functional diversity on plant community responses to drought in the field (open to weed colonization) and greenhouse conditions. Both species and functional diversity positively affected the average yields of field communities. However, this pattern was similar in both drought-stressed and control plots. No effect of diversity on community resistance, biomass recovery after drought and resilience was found because drought reduced biomass production similarly at each level of diversity by approximately 30%. The use of dissimilarity (characterized by Euclidean distance) revealed higher variation under changing environments (drought-stressed vs. control) in more diverse communities compared to less species-rich assemblages. In the greenhouse experiment, the effect of species diversity affected community resistance, indicating that more diverse communities suffered more from drought than species-poor ones. We conclude that our study did not support the insurance hypothesis (stability properties of a community should increase with species richness) because species diversity had an equivocal effect on ecosystem resistance and resilience in an environment held under non-weeded practice, regardless of the positive relationship between sown species diversity and community biomass production. More species-rich communities were less resistant against drought-stressed conditions than species-poor ones grown in greenhouse conditions.

  10. Communities of different plant diversity respond similarly to drought stress: experimental evidence from field non-weeded and greenhouse conditions

    NASA Astrophysics Data System (ADS)

    Lanta, Vojtěch; Doležal, Jiří; Zemková, Lenka; Lepš, Jan

    2012-06-01

    Accelerating rate of species loss has prompted researchers to study the role of species diversity in processes that control ecosystem functioning. Although negative impact of species loss has been documented, the evidence concerning its impact on ecosystem stability is still limited. Here, we studied the effects of declining species and functional diversity on plant community responses to drought in the field (open to weed colonization) and greenhouse conditions. Both species and functional diversity positively affected the average yields of field communities. However, this pattern was similar in both drought-stressed and control plots. No effect of diversity on community resistance, biomass recovery after drought and resilience was found because drought reduced biomass production similarly at each level of diversity by approximately 30 %. The use of dissimilarity (characterized by Euclidean distance) revealed higher variation under changing environments (drought-stressed vs. control) in more diverse communities compared to less species-rich assemblages. In the greenhouse experiment, the effect of species diversity affected community resistance, indicating that more diverse communities suffered more from drought than species-poor ones. We conclude that our study did not support the insurance hypothesis (stability properties of a community should increase with species richness) because species diversity had an equivocal effect on ecosystem resistance and resilience in an environment held under non-weeded practice, regardless of the positive relationship between sown species diversity and community biomass production. More species-rich communities were less resistant against drought-stressed conditions than species-poor ones grown in greenhouse conditions.

  11. A new experimental system for irradiating tumors in mice using a linear accelerator under specific pathogen-free conditions.

    PubMed

    Kuroda, M; Inamura, K; Tahara, S; Kurabayashi, Y; Akagi, T; Asaumi, J; Togami, I; Takemoto, M; Honda, O; Morioka, Y; Kawasaki, S; Hiraki, Y

    1999-06-01

    We developed a reliable system for the irradiation of xenografted tumors in mice which allows for accurate local irradiation under specific pathogen-free conditions. The system presented here consists of acrylic supports for mice and an acrylic box connected to a pump through 0.22 microns pore-sized filters. Mice with xenotransplanted tumors growing on their right hind legs were set on the supports and put into the box in a laminar flow hood. The tumors of 7 mice were irradiated simultaneously with X-rays of 6 and 10 MV generated by a linear accelerator at a dose rate of 3.1-4.7 Gy/min. The air was ventilated through filters during irradiation in the closed box. Microorganism tests confirmed that no bacteria entered or left the box. One of the significant characteristics of this setup is that it allows for irradiation under conditions of acute hypoxia, which is obtained using an integrated tourniquet. The dose variation among 7 tumors was less than 1%. The rest of the mouse's body was shielded effectively by a half-field technique and a lead block. As a result, the whole body dose for the mice was 0-4% of the total dose absorbed by the tumor. Due to the high dose rate and the ability to irradiate 7 mice simultaneously under specific pathogen-free conditions, this new system can be considered a time-saving and valuable tool for radiation oncology research.

  12. Routine experimental system for defining conditions used in photodynamic therapy and fluorescence photodetection of (non-) neoplastic epithelia

    NASA Astrophysics Data System (ADS)

    Lange, Norbert; Vaucher, Laurent; Marti, Alexandre; Etter, Anne-Lise; Gerber, Patrick; van den Bergh, Hubert; Jichlinski, Patrice; Kucera, Pavel

    2001-04-01

    A common method to induce enhanced short-term endogenous porphyrin synthesis and accumulation in cell is the topical, systemic application of 5-aminolevulinic acid or one of its derivatives. This circumvents the intravenous administration of photosensitizers normally used for photodynamic therapy (PDT) of fluorescence photodetection. However, in the majority of potential medical indications, optimal conditions with respect to the porphyrin precursor or its pharmaceutical formulation have not yet been found. Due to ethical restrictions and animal right directives, the number of available test objects is limited. Hence, definition and use of nonanimal test methods are needed. Tissue and organ cultures are a promising approach in replacing cost intensive animal models in early stages of drug development. In this paper, we present a tissue culture, which can among others be used routinely to answer specific questions emerging in the field of photodynamic therapy and fluorescence photodetection. This technique uses mucosae excised from sheep paranasal sinuses or pig bladder, which is cultured under controlled conditions. It allows quasiquantative testing of different protoporphyrin IX precursors with respect to dose-response curves and pharmacokinetics, as well as the evaluation of different incubation conditions and/or different drug formulations. Furthermore, this approach, when combined with the use of electron microscopy and fluorescence-based methods, can be used to quantitatively determine the therapeutic outcome following protoporphyrin IX-mediated PDT.

  13. Design of the Experimental Exposure Conditions to Simulate Ionizing Radiation Effects on Candidate Replacement Materials for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Smith, L. Montgomery

    1998-01-01

    In this effort, experimental exposure times for monoenergetic electrons and protons were determined to simulate the space radiation environment effects on Teflon components of the Hubble Space Telescope. Although the energy range of the available laboratory particle accelerators was limited, optimal exposure times for 50 keV, 220 keV, 350 keV, and 500 KeV electrons were calculated that produced a dose-versus-depth profile that approximated the full spectrum profile, and were realizable with existing equipment. For the case of proton exposure, the limited energy range of the laboratory accelerator restricted simulation of the dose to a depth of .5 mil. Also, while optimal exposure times were found for 200 keV, 500 keV and 700 keV protons that simulated the full spectrum dose-versus-depth profile to this depth, they were of such short duration that the existing laboratory could not be controlled to within the required accuracy. In addition to the obvious experimental issues, other areas exist in which the analytical work could be advanced. Improved computer codes for the dose prediction- along with improved methodology for data input and output- would accelerate and make more accurate the calculational aspects. This is particularly true in the case of proton fluxes where a paucity of available predictive software appears to exist. The dated nature of many of the existing Monte Carlo particle/radiation transport codes raises the issue as to whether existing codes are sufficient for this type of analysis. Other areas that would result in greater fidelity of laboratory exposure effects to the space environment is the use of a larger number of monoenergetic particle fluxes and improved optimization algorithms to determine the weighting values.

  14. Experimental evidence of a link between breeding conditions and the decision to breed or to help in a colonial cooperative bird.

    PubMed Central

    Covas, Rita; Doutrelant, Claire; du Plessis, Morné A.

    2004-01-01

    In many species mature individuals delay independent reproduction and may help others to reproduce. This behaviour is often explained through ecological constraints, although recently attention has also been paid to the variation in habitat quality. If the quality of vacant habitat influences the fitness trade-off between delaying reproduction and breeding independently, individuals should delay reproduction when conditions for breeding are poor. Yet, no study has experimentally manipulated habitat quality or the conditions experienced during the breeding period to test this assertion conclusively. We report results from an experiment conducted on a colonial cooperative bird with no territory constraints on reproduction. We artificially improved breeding conditions in several colonies of sociable weavers, Philetairus socius, through the provision of an easily obtainable and unlimited supply of food. We provide experimental evidence showing that under enhanced conditions some individuals reduce their age at first reproduction, a greater proportion of colony members engage in independent breeding and proportionally fewer birds act as helpers. Hence, these results also provide evidence for a direct influence of reproductive costs on life-history decisions such as age at first reproduction and breeding and helping behaviours. PMID:15255101

  15. 21 CFR 801.5 - Medical devices; adequate directions for use.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Medical devices; adequate directions for use. 801... (CONTINUED) MEDICAL DEVICES LABELING General Labeling Provisions § 801.5 Medical devices; adequate directions for use. Adequate directions for use means directions under which the layman can use a device...

  16. 21 CFR 801.5 - Medical devices; adequate directions for use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical devices; adequate directions for use. 801... (CONTINUED) MEDICAL DEVICES LABELING General Labeling Provisions § 801.5 Medical devices; adequate directions for use. Adequate directions for use means directions under which the layman can use a device...

  17. 21 CFR 801.5 - Medical devices; adequate directions for use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Medical devices; adequate directions for use. 801... (CONTINUED) MEDICAL DEVICES LABELING General Labeling Provisions § 801.5 Medical devices; adequate directions for use. Adequate directions for use means directions under which the layman can use a device...

  18. 21 CFR 801.5 - Medical devices; adequate directions for use.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Medical devices; adequate directions for use. 801... (CONTINUED) MEDICAL DEVICES LABELING General Labeling Provisions § 801.5 Medical devices; adequate directions for use. Adequate directions for use means directions under which the layman can use a device...

  19. 21 CFR 801.5 - Medical devices; adequate directions for use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Medical devices; adequate directions for use. 801... (CONTINUED) MEDICAL DEVICES LABELING General Labeling Provisions § 801.5 Medical devices; adequate directions for use. Adequate directions for use means directions under which the layman can use a device...

  20. Degree of cure and fracture properties of experimental acid-resin modified composites under wet and dry conditions

    PubMed Central

    López-Suevos, Francisco; Dickens, Sabine H.

    2008-01-01

    Objective Evaluate the effects of core structure and storage conditions on the mechanical properties of acid-resin modified composites and a control material by three-point bending and conversion measurements 15 min and 24 h after curing. Methods The monomers pyromellitic dimethacrylate (PMDM), biphenyldicarboxylic-acid dimethacrylate (BPDM), (isopropylidene-diphenoxy)bis(phthalic-acid) dimethacrylate (IPDM), oxydiphthalic-acid dimethacrylate (ODPDM), and Bis-GMA were mixed with triethyleneglycol dimethacrylate (TEGDMA) in a 40/60 molar ratio, and photo-activated. Composite bars (Barium-oxide-glass/resin = 3/1 mass ratio, (2 × 2 × 25) mm, n = 5) were light-cured for 1 min per side. Flexural strength (FS), elastic modulus (E), and work-of-fracture (WoF) were determined in three-point bending after 15 min (stored dry); and after 24 h under dry and wet storage conditions at 37 °C. Corresponding degrees of conversion (DC) were evaluated by Fourier transform infrared spectroscopy. Data was statistically analyzed (2-way analysis of variance, ANOVA, Holm-Sidak, p < 0.05). Results Post-curing significantly increased FS, E and DC in nearly all cases. WoF did not change, or even decreased with time. For all properties ANOVA found significant differences and interactions of time and material. Wet storage reduced the moduli and the other properties measured with the exception of FS and WoF of ODPDM; DC only decreased in BPDM and IPDM composites. Significance Differences in core structure resulted in significantly different physical properties of the composites studied with two phenyl rings connected by one ether linkage as in ODPDM having superior FS, WoF and DC especially after 24 h under wet conditions. As expected, post-curing significantly contributed to the final mechanical properties of the composites, while wet storage generally reduced the mechanical properties. PMID:17980422

  1. Conditioned Medium from Early-Outgrowth Bone Marrow Cells Is Retinal Protective in Experimental Model of Diabetes

    PubMed Central

    Duarte, Diego A.; Papadimitriou, Alexandros; Gilbert, Richard E.; Thai, Kerri; Zhang, Yanling; Rosales, Mariana A. B.; Lopes de Faria, José B.; Lopes de Faria, Jacqueline M.

    2016-01-01

    Bone marrow-derived cells were demonstrated to improve organ function, but the lack of cell retention within injured organs suggests that the protective effects are due to factors released by the cells. Herein, we tested cell therapy using early outgrowth cells (EOCs) or their conditioned media (CM) to protect the retina of diabetic animal models (type 1 and type 2) and assessed the mechanisms by in vitro study. Control and diabetic (db/db) mice (8 weeks of age) were randomized to receive a unique intravenous injection of 5×105EOCs or 0.25 ml thrice weekly tail-vein injections of 10x concentrated CM and Wystar Kyoto rats rendered diabetic were randomized to receive 0.50 ml thrice weekly tail-vein injections of 10x concentrated CM. Four weeks later, the animals were euthanized and the eyes were enucleated. Rat retinal Müller cells (rMCs) were exposed for 24 h to high glucose (HG), combined or not with EOC-conditioned medium (EOC-CM) from db/m EOC cultures. Diabetic animals showed increase in diabetic retinopathy (DR) and oxidative damage markers; the treatment with EOCs or CM infusions significantly reduced this damage and re-established the retinal function. In rMCs exposed to diabetic milieu conditions (HG), the presence of EOC-CM reduced reactive oxygen species production by modulating the NADPH-oxidase 4 system, thus upregulating SIRT1 activity and deacetylating Lys-310-p65-NFκB, decreasing GFAP and VEGF expressions. The antioxidant capacity of EOC-CM led to the prevention of carbonylation and nitrosylation posttranslational modifications on the SIRT1 molecule, preserving its activity. The pivotal role of SIRT1 on the mode of action of EOCs or their CM was also demonstrated on diabetic retina. These findings suggest that EOCs are effective as a form of systemic delivery for preventing the early molecular markers of DR and its conditioned medium is equally protective revealing a novel possibility for cell-free therapy for the treatment of DR. PMID:26836609

  2. [Importance, especially in aeronautics, of color perception tests under dynamic conditions. Study of a suitable experimental apparatus].

    PubMed

    Linzi, S; Modugno, G C; Bollini, M

    1977-12-15

    Following a review of the most recent opinion on the physiology of colour vision, a device for examining it in dynamic, i.e. real-life conditions is described. The apparatus consist of two projectors which flash two absolutely identical pictures on to the screen, one of them is upside down. It appears at fixed but adjustable intervals so that the exposure time of the intelligible image can be varied. Subjects were also controlled with Ishihara charts and Nägel anomaloscope. The results are compared and point to the higher sensitivity of the dynamic test to even slight degrees of dyschromatopsia.

  3. Experimental observation of the thermocapillary driven motion of bubbles in a molten glass under low gravity conditions

    NASA Technical Reports Server (NTRS)

    Smith, H. D.; Mattox, D. M.; Wilcox, W. R.; Subramanian, R. S.; Meyyappan, M.

    1982-01-01

    An experiment was carried out on board a Space Processing Applications Rocket with the aim of demonstrating bubble migration in molten glass due to a temperature gradient under low gravity conditions. During the flight, a sample of a sodium borate melt with a specific bubble array, contained in a platinum/fused silica cell, was subjected to a well defined temperature gradient for more than 4 minutes. Photographs taken at one second intervals during the experiment clearly show that the bubbles move toward the hot spot on the platinum heater strip. This result is consistent with the predictions of the theory of thermocapillary driven bubble motion.

  4. An Experimental Investigation of Flow Conditions in the Vicinity of an NACA D(sub S)-type Cowling

    NASA Technical Reports Server (NTRS)

    Bryant, Rosemary P.; Boswinkle, Robert W.

    1946-01-01

    Data are presented of the flow conditions in the vicinity of an NACA D sub S -type cowling. Tests were made of a 1/2 scale-nacelle model at inlet-velocity ratios ranging from 0.23 to 1.02 and angles of attack from 6 deg to 10 deg. The velocity and direction of flow in the vertical plane of symmetry of the cowling were determined from orifices and tufts installed on a board aligned with the flow. Diagrams showing velocity ratio contours and lines of constant flow angles are given.

  5. Validation of Reference Genes for RT-qPCR Studies of Gene Expression in Preharvest and Postharvest Longan Fruits under Different Experimental Conditions

    PubMed Central

    Wu, Jianyang; Zhang, Hongna; Liu, Liqin; Li, Weicai; Wei, Yongzan; Shi, Shengyou

    2016-01-01

    Reverse transcription quantitative PCR (RT-qPCR) as the accurate and sensitive method is use for gene expression analysis, but the veracity and reliability result depends on whether select appropriate reference gene or not. To date, several reliable reference gene validations have been reported in fruits trees, but none have been done on preharvest and postharvest longan fruits. In this study, 12 candidate reference genes, namely, CYP, RPL, GAPDH, TUA, TUB, Fe-SOD, Mn-SOD, Cu/Zn-SOD, 18SrRNA, Actin, Histone H3, and EF-1a, were selected. Expression stability of these genes in 150 longan samples was evaluated and analyzed using geNorm and NormFinder algorithms. Preharvest samples consisted of seven experimental sets, including different developmental stages, organs, hormone stimuli (NAA, 2,4-D, and ethephon) and abiotic stresses (bagging and girdling with defoliation). Postharvest samples consisted of different temperature treatments (4 and 22°C) and varieties. Our findings indicate that appropriate reference gene(s) should be picked for each experimental condition. Our data further showed that the commonly used reference gene Actin does not exhibit stable expression across experimental conditions in longan. Expression levels of the DlACO gene, which is a key gene involved in regulating fruit abscission under girdling with defoliation treatment, was evaluated to validate our findings. In conclusion, our data provide a useful framework for choice of suitable reference genes across different experimental conditions for RT-qPCR analysis of preharvest and postharvest longan fruits. PMID:27375640

  6. Experimental investigation of laser transmission at 1.06μm in horizontal atmosphere under fine and haze-fog conditions of summer

    NASA Astrophysics Data System (ADS)

    Yin, Kaixin; Qiao, Chunhong; Feng, Xiaoxing; Zhang, Pengfei; Fan, Chengyu

    2016-09-01

    With two sets of experimental instruments, laser transmission was investigated through horizontal atmosphere at 1.06 μm under fine and haze-fog events. One set of the instruments is an indirect transmission meter used to measure visibility and the other one is a direct transmission meter used to measure the attenuation of laser power. Results show that the variation of transmittance got from laser power (Tp) and that obtained by visibility (Tvis) are highly correlated. For relative humidity (RH) below 85%, the curve of Tvis fits that of Tp very well. While the RH is above 85%, the Tvis is more likely smaller than Tp under fine meteorological condition, but under haze-fog condition Tvis is larger than Tp on the contrary. For different weather condition, the relation efficient between extinction coefficient and visibility is different. Even for similar visibility, the extinction coefficient of haze-fog event is larger than that of fine event.

  7. [Effects of melaxen and valdoxan on the activity of glutathione antioxidant system and NADPH-producing enzymes in rat heart under experimental hyperthyroidism conditions].

    PubMed

    Gorbenko, M V; Popova, T N; Shul'gin, K K; Popov, S S

    2013-01-01

    The effects of melaxen and valdoxan on the activity of glutathione antioxidant system and some NADPH-producing enzymes have been studied under conditions of experimental hyperthyroidism in rat heart. Under the action of these drugs, reduced glutathione (GSH) content increased as compared to values observed under the conditions of pathology. It has been established that the activities of glutathione reductase (GR), glutathione peroxidase (GP), glucose-6-phosphate dehydrogenase, and NADP isocitrate dehydrogenase (increased under pathological conditions) change toward the intact control values upon the introduction of both drugs. The influence of melaxen and valdoxan, capable of producing antioxidant effect, leads apparently to the inhibition of free-radical oxidation processes and, as a consequence, the reduction of mobilization degree of the glutathione antioxidant system.

  8. Establishing baseline data for an experimental appratus that measures heat transfer under conditions of oscillating pressure and flow

    NASA Astrophysics Data System (ADS)

    Dean, Charles E.

    1993-05-01

    Mathematical correlations for predicting heat transfer under conditions of oscillating pressure and flow are in their developmental infancy. Such heat transfer is commonly found in reciprocating machinery such as internal combustion engines, gas springs, and Stirling cycle engines. In order to understand and improve the thermodynamic performance of reciprocal engines, it is necessary that mathematical correlations be developed that accurately predict heat loss through the walls of the components within these systems. A heat transfer apparatus has been built that models the oscillating flow of a gas in a pipe as found in the regenerator of a Stirling engine. The apparatus is capable of measuring stream temperature and velocity at any point across the diameter of the pipe, the wall temperature, gas pressure, and gas to wall heat flux. This work addresses the collection of baseline heat transfer data for this apparatus under conditions of oscillating flow and pressure by (1) explaining the addition of a laser Doppler velocimeter to measure stream velocities, (2) investigating velocity profiles within the test section as the flow oscillates, and (3) recording and analyzing baseline heat transfer data. Results show a close correlation between the phase angle between the two compressors mounted at each end of the test section and the complex-valued Nusselt number that has been derived.

  9. The relationship between geophysical conditions and ELF amplitude in modulated heating experiments at HAARP: Modeling and experimental results

    NASA Astrophysics Data System (ADS)

    Jin, G.; Spasojevic, M.; Cohen, M. B.; Inan, U. S.; Lehtinen, N. G.

    2011-07-01

    Experiments for generating extremely low frequency (ELF) radio waves using modulated HF heating of the auroral ionosphere have been conducted and refined at the High Frequency Active Auroral Research Program (HAARP) facility at Gakona, Alaska. Because this technique is dependent on strength of the naturally generated electrojet current system, the amplitude of the generated ELF changes with geophysical conditions. Past work has shown that electrojet current strength as measured by magnetometers often correlates with generated ELF amplitude, but there are periods of poor or negative correlation. We attempt to use additional diagnostics from a radar, riometer, ionosonde, and magnetometer chain to understand how ionospheric conditions affect ELF generation. We then present the results of a statistical model that shows that ELF amplitude is roughly proportional to magnetometer measurements for a fixed value of riometer absorption and that the proportionality constant decreases as riometer absorption increases. Theoretical simulations of modulated heating are conducted for a variety of ionospheric density profiles to verify that denser profiles result in smaller gains for ELF generation as a function of electrojet current at a given electric field.

  10. How mobile is iodide in the Callovo-Oxfordian claystones under experimental conditions close to the in situ ones?

    PubMed

    Savoye, Sébastien; Frasca, Benjamin; Grenut, Bernard; Fayette, Agnès

    2012-11-01

    The iodide behaviour towards the Callovo-Oxfordian claystone was studied using batch and diffusion experiments under conditions which limited the artefacts cited in the literature to be responsible for the iodide uptake (i.e. the experiments were carried out under anoxic conditions with N(2)/CO(2) atmosphere with a monitoring of the iodine redox-state). The results show that all the radioactive iodine was (125)I(-), with no measurable activity for (125)IO(3)(-), which is known to have a higher affinity for the rock than iodide. Moreover, the batch experiments revealed no sorption, independently of the initial iodide concentration (from 10(-6) to 10(-3) mol L(-1)) and the contact time (up to 106 days). Conversely, the diffusion experiments indicated a weak but measurable retention. The through-diffusion experiments led to distribution ratio values only significant (R(D)~0.05 mL g(-1)) for initial iodide concentration ≤ 10(-4) mol L(-1). Higher R(D) values were estimated from out-diffusion experiments, ranging from about 0.05 mL g(-1) for an initial concentration of 10(-3) mol L(-1) to 0.14 mL g(-1) for the lowest one. A retention phenomenon that could be reversible and kinetically-controlled was proposed to explain the differences in the extent of the iodide retardation of the two types of diffusion experiments.

  11. [Influence of GABA derivatives on some indices of lipid peroxidation in immunocompetent organs under experimental immunopathology conditions].

    PubMed

    Samotrueva, M A; Magomedov, M M; Khlebtsova, E B; Tiurenkov, I N

    2011-01-01

    The effects of GABA derivatives phenotropil (25 mg/kg), phenibut (25 mg/kg), and baclofen (2 mg/kg) on the process of lipid peroxidation (LPO), as manifested by the initial level of malonic dialdehyde, velocity of spontaneous and ascorbate-dependent LPO, and the catalase activity in the homogenates of thymus and spleen, have been studied on rats of the Wistar line with cyclophosphamide (CPHA) immunodepression and lipopolysacharide (LPS) immune stress. It is established that, under the action of CPHA and LPS, activation of the LPO processes takes place in the immune organs. Under these conditions, changes of the catalase activity exhibited some specific features: in the animals under LPS action, the catalase activity increased in the spleen, while being decreased in the thymus; under the influence of CPHA, the activity of this enzyme decreased in both organs. An analysis of the antioxidant activity of GABA derivatives under the conditions of CPHA-induced immunodepression showed that all substances upon intraperitoneal introduction for 5 days favored the elimination of disturbances by suppressing the LPO processes and increasing the antioxidant protection activity. On the background of LPS-induced immune stress, all the tested substances showed a correcting action with respect to indicated biochemical processes in the thymus, while only phenibut activated the antioxidant system in the spleen.

  12. Experimental investigation of the effects of the acoustical conditions in a simulated classroom on speech recognition and learning in children.

    PubMed

    Valente, Daniel L; Plevinsky, Hallie M; Franco, John M; Heinrichs-Graham, Elizabeth C; Lewis, Dawna E

    2012-01-01

    The potential effects of acoustical environment on speech understanding are especially important as children enter school where students' ability to hear and understand complex verbal information is critical to learning. However, this ability is compromised because of widely varied and unfavorable classroom acoustics. The extent to which unfavorable classroom acoustics affect children's performance on longer learning tasks is largely unknown as most research has focused on testing children using words, syllables, or sentences as stimuli. In the current study, a simulated classroom environment was used to measure comprehension performance of two classroom learning activities: a discussion and lecture. Comprehension performance was measured for groups of elementary-aged students in one of four environments with varied reverberation times and background noise levels. The reverberation time was either 0.6 or 1.5 s, and the signal-to-noise level was either +10 or +7 dB. Performance is compared to adult subjects as well as to sentence-recognition in the same condition. Significant differences were seen in comprehension scores as a function of age and condition; both increasing background noise and reverberation degraded performance in comprehension tasks compared to minimal differences in measures of sentence-recognition.

  13. Experimental Evidence for Fast Lithium Diffusion and Isotope Fractionation in Water-bearing Rhyolitic Melts at Magmatic Conditions

    NASA Astrophysics Data System (ADS)

    Cichy, S. B.; Till, C. B.; Roggensack, K.; Hervig, R. L.; Clarke, A. B.

    2015-12-01

    The aim of this work is to extend the existing database of experimentally-determined lithium diffusion coefficients to more natural cases of water-bearing melts at the pressure-temperature range of the upper crust. In particular, we are investigating Li intra-melt and melt-vapor diffusion and Li isotope fractionation, which have the potential to record short-lived magmatic processes (seconds to hours) in the shallow crust, especially during decompression-induced magma degassing. Hydrated intra-melt Li diffusion-couple experiments on Los Posos rhyolite glass [1] were performed in a piston cylinder at 300 MPa and 1050 °C. The polished interfaces between the diffusion couples were marked by addition of Pt powder for post-run detection. Secondary ion mass spectrometry analyses indicate that lithium diffuses extremely fast in the presence of water. Re-equilibration of a hydrated ~2.5 mm long diffusion-couple experiment was observed during the heating period from room temperature to the final temperature of 1050 °C at a rate of ~32 °C/min. Fractionation of ~40‰ δ7Li was also detected in this zero-time experiment. The 0.5h and 3h runs show progressively higher degrees of re-equilibration, while the isotope fractionation becomes imperceptible. Li contamination was observed in some experiments when flakes filed off Pt tubing were used to mark the diffusion couple boundary, while the use of high purity Pt powder produced better results and allowed easier detection of the diffusion-couple boundary. The preliminary lithium isotope fractionation results (δ7Li vs. distance) support findings from [2] that 6Li diffuses substantially faster than 7Li. Further experimental sets are in progress, including lower run temperatures (e.g. 900 °C), faster heating procedure (~100 °C/min), shorter run durations and the extension to mafic systems. [1] Stanton (1990) Ph.D. thesis, Arizona State Univ., [2] Richter et al. (2003) GCA 67, 3905-3923.

  14. Improving single molecule force spectroscopy through automated real-time data collection and quantification of experimental conditions

    PubMed Central

    Scholl, Zackary N.; Marszalek, Piotr E.

    2013-01-01

    The benefits of single molecule force spectroscopy (SMFS) clearly outweigh the challenges which include small sample sizes, tedious data collection and introduction of human bias during the subjective data selection. These difficulties can be partially eliminated through automation of the experimental data collection process for atomic force microscopy (AFM). Automation can be accomplished using an algorithm that triages usable force-extension recordings quickly with positive and negative selection. We implemented an algorithm based on the windowed fast Fourier transform of force-extension traces that identifies peaks using force-extension regimes to correctly identify usable recordings from proteins composed of repeated domains. This algorithm excels as a real-time diagnostic because it involves <30 ms computational time, has high sensitivity and specificity, and efficiently detects weak unfolding events. We used the statistics provided by the automated procedure to clearly demonstrate the properties of molecular adhesion and how these properties change with differences in the cantilever tip and protein functional groups and protein age. PMID:24001740

  15. [Postnatal development of zinc levels in the epididymis and testis in rats under normal and experimental conditions].

    PubMed

    Delongeas, J L; Hutin, M F; Burnel, D; Grignon, G

    1987-01-01

    Postnatal testicular and epididymal zinc concentration in the rat was investigated by means of differential pulse polarography. The zinc concentration increased gradually from birth to day 90 in the testis and up to day 60-90 in the epididymis with an abrupt increase on day 21. No marked variation in the zinc content was observed all along the epididymal duct. Experimental castration and efferent duct ligation were carried out in order to assess the influence of blood-borne and luminal androgens on epididymal zinc content. In prepubertal rats, unilateral castration and efferent duct ligation did not affect the zinc content of the epididymis. Moreover, zinc concentration was not affected by bilateral castration which induced very low plasma testosterone levels. These results suggested that epididymal zinc content did not depend upon endocrine testicular secretions, especially androgens. On the other hand, in adult rats efferent duct ligation and cryptorchidism resulted in about 50 and 70% reduction, respectively of the testicular and epididymal zinc content. A correlation was found between the absence of testicular fluid and spermatozoa or the alteration of germ cells and the decrease in epididymal and testicular zinc content.

  16. Experimental and theoretical characterization of microbial bioanodes formed in pulp and paper mill effluent in electrochemically controlled conditions.

    PubMed

    Ketep, Stephanie F; Fourest, Eric; Bergel, Alain

    2013-12-01

    Microbial bioanodes were formed in pulp and paper effluent on graphite plate electrodes under constant polarization at -0.3 V/SCE, without any addition of nutriment or substrate. The bioanodes were characterized in 3-electrode set-ups, in continuous mode, with hydraulic retention times from 6 to 48 h and inlet COD from 500 to 5200 mg/L. Current densities around 4A/m(2) were obtained and voltammetry curves indicated that 6A/m(2) could be reached at +0.1 V/SCE. A theoretical model was designed, which allowed the effects of HRT and COD to be distinguished in the complex experimental data obtained with concomitant variations of the two parameters. COD removal due to the electrochemical process was proportional to the hydraulic retention time and obeyed a Michaelis-Menten law with respect to the COD of the outlet flow, with a Michaelis constant KCOD of 400mg/L. An inhibition effect occurred above inlet COD of around 3000 mg/L.

  17. Investigation of As, Mn and Fe fixation inside the aquifer during groundwater exploitation in the experimental system imitated natural conditions.

    PubMed

    Dung, Nguyen Thi Kim; Con, Tran Hong; Cam, Bui Duy; Kang, Yumei

    2012-06-01

    Water-dissolved oxygen was supplied into anaerobic aquifer , which oxidized Fe(II), Mn(II) and trivalent arsenic and changed them into undissolved solid matter through hydrolysis, precipitation, co-precipitation and adsorption processes. The experiment was carried out on the column imitated a bore core of anaerobic aquifer with water phase containing Fe(II), Mn(II), As(III) concentration of 45.12 mg/L, 14.52 mg/L, 219.4 μg/L, respectively and other ions similarly composition in groundwater. After 6 days of air supply, concentration of iron reduced to 0.38 mg/L, manganese to 0.4 mg/L, arsenic to 9.8 μg/L (equivalent 99.16% of iron, 97.25% of manganese and 95.53% of arsenic fixed), and for other ions, the concentration changed almost according to general principles. Ion phosphate and silicate strongly influenced on arsenic removal but supported iron and manganese precipitation from water phase. Based on the experimental results, new model of groundwater exploitation was proposed.

  18. Electrophysiological effects of non-invasive Radio Electric Asymmetric Conveyor (REAC) on thalamocortical neural activities and perturbed experimental conditions

    PubMed Central

    Zippo, Antonio G.; Rinaldi, Salvatore; Pellegata, Giulio; Caramenti, Gian Carlo; Valente, Maurizio; Fontani, Vania; Biella, Gabriele E. M.

    2015-01-01

    The microwave emitting Radio Electric Asymmetric Conveyor (REAC) is a technology able to interact with biological tissues at low emission intensity (2 mW at the emitter and 2.4 or 5.8 GHz) by inducing radiofrequency generated microcurrents. It shows remarkable biological effects at many scales from gene modulations up to functional global remodeling even in human subjects. Previous REAC experiments by functional Magnetic Resonance Imaging (fMRI) on healthy human subjects have shown deep modulations of cortical BOLD signals. In this paper we studied the effects of REAC application on spontaneous and evoked neuronal activities simultaneously recorded by microelectrode matrices from the somatosensory thalamo-cortical axis in control and chronic pain experimental animal models. We analyzed the spontaneous spiking activity and the Local Field Potentials (LFPs) before and after REAC applied with a different protocol. The single neuron spiking activities, the neuronal responses to peripheral light mechanical stimuli, the population discharge synchronies as well as the correlations and the network dynamic connectivity characteristics have been analyzed. Modulations of the neuronal frequency associated with changes of functional correlations and significant LFP temporal realignments have been diffusely observed. Analyses by topological methods have shown changes in functional connectivity with significant modifications of the network features. PMID:26658170

  19. The Effects of Experimental Conditions on the Refractive Index and Density of Low-Temperature Ices: Solid Carbon Dioxide

    NASA Technical Reports Server (NTRS)

    Loeffler, M. J.; Moore, M. H.; Gerakines, P. A.

    2016-01-01

    We present the first study on the effects of the deposition technique on the measurements of the visible refractive index and the density of a low-temperature ice using solid carbon dioxide (CO2) at 14-70 K as an example. While our measurements generally agree with previous studies that show a dependence of index and density on temperature below 50 K, we also find that the measured values depend on the method used to create each sample. Below 50 K, we find that the refractive index varied by as much as 4% and the density by as much as 16% at a single temperature depending on the deposition method. We also show that the Lorentz-Lorenz approximation is valid for solid CO2 across the full 14-70 K temperature range, regardless of the deposition method used. Since the refractive index and density are important in calculations of optical constants and infrared (IR) band strengths of materials, our results suggest that the deposition method must be considered in cases where nvis and ? are not measured in the same experimental setup where the IR spectral measurements are made.

  20. Direct molecular dynamics simulation of Ge deposition on amorphous SiO2 at experimentally relevant conditions

    DOE PAGES

    Chuang, Claire Y.; Zepeda-Ruiz, Luis A.; Han, Sang M.; ...

    2015-06-01

    Molecular dynamics simulations were used to study Ge island nucleation and growth on amorphous SiO2 substrates. This process is relevant in selective epitaxial growth of Ge on Si, for which SiO2 is often used as a template mask. The islanding process was studied over a wide range of temperatures and fluxes, using a recently proposed empirical potential model for the Si–SiO2–Ge system. The simulations provide an excellent quantitative picture of the Ge islanding and compare well with detailed experimental measurements. These quantitative comparisons were enabled by an analytical rate model as a bridge between simulations and experiments despite the factmore » that deposition fluxes accessible in simulations and experiments are necessarily different by many orders of magnitude. In particular, the simulations led to accurate predictions of the critical island size and the scaling of island density as a function of temperature. Lastly, the overall approach used here should be useful not just for future studies in this particular system, but also for molecular simulations of deposition in other materials.« less

  1. Direct molecular dynamics simulation of Ge deposition on amorphous SiO2 at experimentally relevant conditions

    SciTech Connect

    Chuang, Claire Y.; Zepeda-Ruiz, Luis A.; Han, Sang M.; Sinno, Talid

    2015-06-01

    Molecular dynamics simulations were used to study Ge island nucleation and growth on amorphous SiO2 substrates. This process is relevant in selective epitaxial growth of Ge on Si, for which SiO2 is often used as a template mask. The islanding process was studied over a wide range of temperatures and fluxes, using a recently proposed empirical potential model for the Si–SiO2–Ge system. The simulations provide an excellent quantitative picture of the Ge islanding and compare well with detailed experimental measurements. These quantitative comparisons were enabled by an analytical rate model as a bridge between simulations and experiments despite the fact that deposition fluxes accessible in simulations and experiments are necessarily different by many orders of magnitude. In particular, the simulations led to accurate predictions of the critical island size and the scaling of island density as a function of temperature. Lastly, the overall approach used here should be useful not just for future studies in this particular system, but also for molecular simulations of deposition in other materials.

  2. Electrophysiological effects of non-invasive Radio Electric Asymmetric Conveyor (REAC) on thalamocortical neural activities and perturbed experimental conditions.

    PubMed

    Zippo, Antonio G; Rinaldi, Salvatore; Pellegata, Giulio; Caramenti, Gian Carlo; Valente, Maurizio; Fontani, Vania; Biella, Gabriele E M

    2015-12-11

    The microwave emitting Radio Electric Asymmetric Conveyor (REAC) is a technology able to interact with biological tissues at low emission intensity (2 mW at the emitter and 2.4 or 5.8 GHz) by inducing radiofrequency generated microcurrents. It shows remarkable biological effects at many scales from gene modulations up to functional global remodeling even in human subjects. Previous REAC experiments by functional Magnetic Resonance Imaging (fMRI) on healthy human subjects have shown deep modulations of cortical BOLD signals. In this paper we studied the effects of REAC application on spontaneous and evoked neuronal activities simultaneously recorded by microelectrode matrices from the somatosensory thalamo-cortical axis in control and chronic pain experimental animal models. We analyzed the spontaneous spiking activity and the Local Field Potentials (LFPs) before and after REAC applied with a different protocol. The single neuron spiking activities, the neuronal responses to peripheral light mechanical stimuli, the population discharge synchronies as well as the correlations and the network dynamic connectivity characteristics have been analyzed. Modulations of the neuronal frequency associated with changes of functional correlations and significant LFP temporal realignments have been diffusely observed. Analyses by topological methods have shown changes in functional connectivity with significant modifications of the network features.

  3. Rapid and persistent change of microbial community and gross N turnover under experimentally simulated climate change conditions in alpine grassland

    NASA Astrophysics Data System (ADS)

    Wang, Changhui; Chen, Zhe; Unteregelsbacher, Sebastian; Gschwendtner, Silvia; Schloter, Michael; Butterbach-Bahl, Klaus; Dannenmann, Michael

    2013-04-01

    Alpine grasslands of Central Europe are exposed to strong warming and to altered precipitation patterns, suggesting that ecosystem nitrogen (N) cycling may be vulnerable to future climatic conditions. In order to investigate the response of soil microbial community and N transformations to predicted climate change conditions, we conducted an ecosystem manipulation experiment following the "space for time" approach in the TERENO (Terrestrial Environmental Observatories) pre-alpine grassland observatory. For this purpose, we dislocated 200 mini-lysimeters containing intact plant-soil systems down an altitudinal gradient from 860m to 550m above sea level, with corresponding control transfers within the high altitude site. After an equilibration period of 2.5 years, a full annual cycle of gross rates of N turnover as well as microbial biomass- and -community dynamics was monitored based on 15 sampling dates in two soil layers. For the monitored year, simulation of climate change via lysimeter transfer had increased mean annual soil temperature in 5 cm depth on average by 2.4 °C, but on the other hand promoted soil frost in winter due to reduced snow cover. Soil moisture was decreased on average by 20%. Gross N turnover and the abundance of N cycle genes in soil were characterized by pronounced seasonal dynamics, with both summer and winter representing key periods for the annual sum of N turnover. The abundance of ammonia oxidizing archae (AOA) genes exceeded the abundance of ammonia oxidizing bacterial (AOB) genes by approximately three orders of magnitude. Climate change simulation strongly increased the abundance of both AOB and AOA gene copies in soil, consistent with an increase of annual gross nitrification rates by 41%. Gross N mineralization was even increased by 141% in the climate change treatment. The abundance of AOA genes in soil explained 80% of the variability of gross nitrification rates over the full annual course. These results provide strong

  4. River bed armoring in a local scour under no-supply conditions; experimental investigation and numerical model validation

    NASA Astrophysics Data System (ADS)

    Török, Gergerly; Baranya, Sandor; Rüther, Nils

    2016-04-01

    The aim of this study is to present a novel method for numerical modeling of morphological changes. The essence of the method doesn't mean the development of a new sediment transport formula, but the combined application of the existing, conditionally validated sediment transport models. Many bedload transport formulas can be found in the literature, which were developed based on different field and laboratory measurements. Thus, the most reliability of the models usually can be expected only for the given morphological and hydrological conditions connected to the base measurements. However, commonly in the analysed cases the morphological and hydrological features are more variable both in time and in space. Therefore, the hypothesis of this study is that, complex hydromorphological processes can't be modeled by one sediment transport formula. The authors present a solution based on laboratory experiments. Spatio-temporal developments of bed armoring, local scouring and local sediment deposition under no supply condition was monitored and analysed. The sediment transport model of Wilcock and Crowe (2003) was expected to calculate properly the local scouring and bed armoring processes, while the motion and aggradation of the finer materials were supposed to estimate reliably by the van Rijn formula (1984). The main challenge of the combining method is to find an appropriate criterion to decide which transport formula is activated in the given space and in the given time step. The result of the investigation showed that the most reliable criteria is based on the d50 value. As soon as the d50 grain size goes below a certain value, van Rijn is activated, otherwise the Wilcock and Crowe formula calculates the sorting and armoring processes. The results show that the combining method clearly improve the reliability of the morphological calculation. The benefit of the Wilcock and Crowe model is that it estimates quite well the sediment transport in mixed or armored

  5. Experimental constraints on the P/T conditions of high silica andesite storage preceding the 2006 eruption of Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Henton, S.; Larsen, J. F.; Traxler, N.

    2010-12-01

    We present new experimental results to constrain the P/T storage conditions of the high silica andesite (HSA) prior to the 2006 eruption of Augustine Volcano, Alaska. Augustine Volcano forms a small island located in Alaska’s Cook Inlet, approximately 180 miles southwest of Anchorage. The 2006 eruption began January 11, 2006, and evolved from an initial phase of explosive activity, through continuous and effusive phases, ending approximately mid-March 2006. Lithologies erupted indicate pervasive hybridization between high- (HSA; 62.2-63.3 wt. % SiO2) and low-silica andesite (LSA; 56.6-58.7 wt% SiO2). This study focuses on experiments using the HSA as starting material to constrain magma storage conditions, based on amphibole stability. Experiments were conducted between 100-160 MPa and 800-900 °C, utilzing H2O saturated conditions and fO2 of Re-ReO. Both lightly crushed and sintered HSA were used as starting powders, seeded respectively with 5 wt. % amphibole and a mix of 5 wt. % amphibole and 20 wt. % plagioclase. Experiments with sintered starting material tended toward a bimodal distribution of experimental phenocrysts and microlites, whilst experiments of the lightly crushed material are more phenocryst rich. Preliminary results indicate that amphibole is stable at conditions of 120-140 MPa and 820-840 °C. These pressures correspond with depths of approximately 4.6-5.4 km, which are consistent with prior magma storage models for Augustine 1986 and 2006 magmas, as well as amphiboles found in other arc andesites (e.g., Redoubt and Soufriere Hills volcanoes). Experimental amphiboles are magnesio-hornblendes, which is in keeping with the natural HSA amphiboles. Experimental and natural hornblendes are similar in composition, with the main difference being a small FeO enrichment (2-3 wt%) and MgO depletion (1-2wt%) in the experimental grains. Further work will provide a more complete assessment of amphibole stability and composition, and will be applied towards

  6. An Experimental and Modeling Study of Evaporation from Bare Soils Subjected to Natural Boundary Conditions at the Land-Atmospheric Interface

    NASA Astrophysics Data System (ADS)

    Smits, K. M.; Ngo, V. V.; Cihan, A.; Sakaki, T.; Illangasekare, T. H.; kathleen m smits

    2011-12-01

    Bare soil evaporation is a key process for water exchange between the land and the atmosphere and an important component of the water balance in semiarid and arid regions. However, there is no agreement on the best methodology to determine evaporation under different boundary conditions. Because it is difficult to measure evaporation from soil,with the exception of using lysimeters, numerous formulations have been proposed to establish a relationship between the rate of evaporation and soil moisture and/or soil temperature and thermal properties. Different formulations vary in how they partition available energy and include, among others, a classical bulk aerodynamic formulation which requires knowledge of the relative humidity at the soil surface and a more non-traditional heat balance method which requires knowledge of soil temperature and soil thermal properties. A need exists to systematically compare existing methods to experimental data under highly controlled conditions not achievable in the field. The goal of this work is to perform controlled experiments under transient conditions of soil moisture, temperature and wind at the land/atmospheric interface to test different conceptual and mathematical formulations for evaporation rate estimates and to develop appropriate numerical models to be used in simulations. In this study, to better understand the coupled water-vapor-heat flow processes in the shallow subsurface near the land surface, we modified a previously developed theory that allows non-equilibrium liquid/gas phase change with gas phase vapor diffusion to better account for evaporation under dry soil conditions. This theory was used to compare estimates of evaporation based on different formulations of the bulk aerodynamic and heat balance methods. In order to experimentally validate the numerical formulations/code, we performed a series of two-dimensional physical model experiments under varying boundary conditions using test sand for which the

  7. Comparison of 'HoBi'-like viral populations among persistent infected calves generated under experimental conditions and to inoculum virus.

    PubMed

    Weber, M N; Bauermann, F V; Bayles, D O; Canal, C W; Neill, J D; Ridpath, J F

    2016-05-01

    Like other members from the Pestivirus genus, 'HoBi'-like pestiviruses cause economic losses for cattle producers due to both acute and persistent infections. The present study analyzed for the first time PI animals derived from a controlled infection with two different 'HoBi'-like strains where the animals were maintained under conditions where superinfection by other pestiviruses could be excluded. The sequence of the region coding for viral glycoproteins E1/E2 of variants within the swarms of viruses present in the PI calves and two viral inoculums used to generate them were compared. Differences in genetic composition of the viral swarms were observed suggesting that host factors can play a role in genetic variations among PIs. Moreover, PIs generated with the same inoculum showed amino acid substitutions in similar sites of the polyprotein, even in serum from PIs with different quasispecies composition, reinforcing that some specific sites in E2 are important for host adaptation.

  8. Boundary conditions in the vicinity of a dynamic contact line: experimental investigation of viscous drops sliding down an inclined plane.

    PubMed

    Rio, E; Daerr, A; Andreotti, B; Limat, L

    2005-01-21

    To probe the microscopic balance of forces close to a moving contact line, the boundary conditions around viscous drops sliding down an inclined plane are investigated. At first, the variation of the contact angle as a function of the scale of analysis is discussed. The dynamic contact angle is measured at a scale of 6 mum all around sliding drops for different volumes and speeds. We show that it depends only on the capillary number based on the local liquid velocity, measured by particle tracking. This velocity turns out to be normal to the contact line everywhere. It indirectly proves that, in comparison with the divergence involved in the normal direction, the viscous stress is not balanced by intermolecular forces in the direction tangential to the contact line, so that any motion in this last direction gets damped.

  9. Evaluation of experimentally measured and model-calculated pH for rock-brine-CO2 systems under geologic CO2 sequestration conditions

    SciTech Connect

    Shao, Hongbo; Thompson, Christopher J.; Cantrell, Kirk J.

    2013-11-14

    pH is an essential parameter for understanding the geochemical reactions that occur in rock-brine-CO2 systems when CO2 is injected into deep geologic formations for long-term storage. Due to a lack of reliable experimental methods, most laboratory studies conducted under geological CO2 sequestration (GCS) conditions have relied on thermodynamic modeling to estimate pH. The accuracy of these model predictions is typically uncertain. In our previous work, we have developed a method for pH determination by in-situ spectrophotometry. In the present work, we expanded the applicable pH range for this method and measured the pH of several rock-brine-CO2 systems at GCS conditions for five rock samples collected from ongoing GCS demonstration projects. Experimental measurements were compared with pH values calculated using several geochemical modeling approaches. The effect of different thermodynamic databases on the accuracy of model prediction was evaluated. Results indicate that the accuracy of model calculations is rock-dependent. For rocks comprised of carbonate and sandstone, model results generally agreed well with experimentally measured pH; however, for basalt, significant differences were observed. These discrepancies may be due to the models’ failure to fully account for certain reaction occurring between the basalt minerals the CO2-saturated brine solutions.

  10. Removal of cobalt ions from aqueous solutions by polymer assisted ultrafiltration using experimental design approach. part 1: optimization of complexation conditions.

    PubMed

    Cojocaru, Corneliu; Zakrzewska-Trznadel, Grazyna; Jaworska, Agnieszka

    2009-09-30

    The polymer assisted ultrafiltration process combines the selectivity of the chelating agent with the filtration ability of the membrane acting in synergy. Such hybrid process (complexation-ultrafiltration) is influenced by several factors and therefore the application of experimental design for process optimization using a reduced number of experiments is of great importance. The present work deals with the investigation and optimization of cobalt ions removal from aqueous solutions by polymer enhanced ultrafiltration using experimental design and response surface methodological approach. Polyethyleneimine has been used as chelating agent for cobalt complexation and the ultrafiltration experiments were carried out in dead-end operating mode using a flat-sheet membrane made from regenerated cellulose. The aim of this part of experiments was to find optimal conditions for cobalt complexation, i.e. the influence of initial concentration of cobalt in feed solution, polymer/metal ratio and pH of feed solution, on the rejection efficiency and binding capacity of the polymer. In this respect, the central compositional design has been used for planning the experiments and for construction of second-order response surface models applicable for predictions. The analysis of variance has been employed for statistical validation of regression models. The optimum conditions for maximum rejection efficiency of 96.65% has been figured out experimentally by gradient method and was found to be as follows: [Co(2+)](0)=65 mg/L, polymer/metal ratio=5.88 and pH 6.84.

  11. Experimental Investigation of Augmented Spark Ignition of a LO2/LCH4 Reaction Control Engine at Altitude Conditions

    NASA Technical Reports Server (NTRS)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of nontoxic propellants in future exploration vehicles would enable safer, more cost-effective mission scenarios. One promising green alternative to existing hypergols is liquid methane (LCH4) with liquid oxygen (LO2). A 100 lbf LO2/LCH4 engine was developed under the NASA Propulsion and Cryogenic Advanced Development project and tested at the NASA Glenn Research Center Altitude Combustion Stand in a low pressure environment. High ignition energy is a perceived drawback of this propellant combination; so this ignition margin test program examined ignition performance versus delivered spark energy. Sensitivity of ignition to spark timing and repetition rate was also explored. Three different exciter units were used with the engine s augmented (torch) igniter. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks. This suggests that rising pressure and flow rate increase spark impedance and may at some point compromise an exciter s ability to complete each spark. The reduced spark energies of such quenched deliveries resulted in more erratic ignitions, decreasing ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1 to 6 mJ, though multiple, similarly timed sparks of 55 to 75 mJ were required for reliable ignition. Delayed spark application and reduced spark repetition rate both correlated with late and occasional failed ignitions. An optimum time interval for spark application and ignition therefore coincides with propellant introduction to the igniter.

  12. Experimental Demonstration of the Formation of Liquid Brines under Martian Polar Conditions in the Michigan Mars Environmental Chamber

    NASA Astrophysics Data System (ADS)

    Fischer, Erik; Martinez, German; Elliott, Harvey; Borlina, Caue; Renno, Nilton

    2014-05-01

    Liquid water is one of the necessary ingredients for the development of life as we know it. The behavior of various liquid states of H2O such as liquid brine, undercooled liquid interfacial water, subsurface melt water and ground water [1] needs to be understood in order to address the potential habitability of Mars for microbes and future human exploration. It has been shown thermodynamically that liquid brines can exist under Martian polar conditions [2, 3]. We have developed the Michigan Mars Environmental Chamber (MMEC) to simulate the entire range of Martian surface and shallow subsurface conditions with respect to temperature, pressure, relative humidity, solar radiation and soil wetness at equatorial and polar latitudes. Our experiments in the MMEC show that deliquescence of NaClO4, Mg(ClO4)2 and Ca(ClO4)2 occurs diurnally under the environmental conditions of the Phoenix landing site when these salts get in contact with water ice. Since Phoenix detected these salts and water ice at the landing site, including frost formation, it is extremely likely that deliquescence occurs at the Phoenix landing site. By layering NaClO4, Mg(ClO4)2 or Ca(ClO4)2 on top of a pure water ice slab at 800 Pa and 190 K and raising the temperature stepwise across the eutectic temperature of the perchlorate salts, we observe distinct changes in the Raman spectra of the samples when deliquescence occurs. When crossing the eutectic temperatures of NaClO4 (236 K), Mg(ClO4)2 (205 K) and Ca(ClO4)2 (199 K) [4, 5], the perchlorate band of the Raman spectrum shows a clear shift from 953 cm-1 to 936 cm-1. Furthermore, the appearance of a broad O-H vibrational stretching spectrum between 3244 cm-1 and 3580 cm-1 is another indicator of deliquescence. This process of deliquescence occurs on the order of seconds when the perchlorate salt is in contact with water ice. On the contrary, when the perchlorate salt is only subjected to water vapor in the Martian atmosphere, deliquescence was not

  13. Experimental study on propagation of liquid-filled crack in gelatin: Shape and velocity in hydrostatic stress condition

    NASA Astrophysics Data System (ADS)

    Takada, Akira

    1990-06-01

    The three-dimensional shape and velocity of propagating cracks in the hydrostatic stress condition were studied by using gelatin, the physical properties of which were controlled to be constant. Various liquids (with various densities, viscosities, and volumes as the governed parameters) were injected in gelatin to form liquid-filled cracks. The directions of the crack growth and the propagation of an isolated crack are governed by the density difference between injected liquid and gelatin (Δρ), that is, a buoyancy. The propagation of a crack has two critical values: the first is the transition value to brittle fracture; the second is the value where segmentation begins to occur. The condition of a stable isolated crack formation is discussed. The crack shape of an isolated crack in the direction perpendicular to the crack plane is different from that of a growing crack with a fat tear drop form: the former has an elliptical top and a nearly flat bottom. The upper termination of an isolated crack in the vertical cross section has an elliptical shape, and the lower termination has a cusped shape. The lower part of the crack occupies the preexiting fracture which has formed by fracturing at the crack top. The crack thickness (w)/crack height (h) ratio is proportional to Δρ A, if the elastic moduli are constant. The crack length l/h ratio increase with h in the primary fracture, while the l/h ratio decreases with h in the preexisting fracture except for air-filled cracks. The ascending velocity of an isolated crack is proportional to Δρ3 h4, that is, Δρ w2, if the other physical properties are constant. The height and length of a growing penny-shaped crack are approximately proportional to A 3d1/3t4/9, so that the growth rate of height is in proportion to A3d3t-5/9 (A3d is constant injection rale). Some comparisons with the two-dimensional crack theory and applications for magma-filled cracks are discussed on the basis of these results.

  14. Experimental and theoretical investigations of Cs-Ba vapor tacitron inverter for power conditioning in space power systems. Annual report, April 15, 1992--April 14, 1993

    SciTech Connect

    El-Genk, M.; Murray, C.; Wernsman, B.

    1993-01-01

    The operation characteristics of the Cs-Ba tacitron as a switch are investigated experimentally in three modes: (a) breakdown mode, (b) I-V mode, and (c) current modulation mode. The switching frequency, grid potentials for ignition and extinguishing of discharge, and the Cs pressure and emission conditions (Ba pressure and emitter temperature) for stable current modulation are determined. The experimental data is also used to determine the off-time required for successful ignition, and the effects of the aforementioned operation parameters on the ignition duty cycle threshold for stable modulation. Operation parameters measured include switching frequency up to 20 kHz, hold-off voltage up to 180 V, current densities in excess of 15 A/cm{sup 2}, switch power density of 1 kW/cm{sup 2}. and a switching efficiency in excess of 90% at collector C: realer than 30 V. The voltage drop strongly depends on the Cs pressure and to a lesser extent on the emission conditions. Increasing the Cs pressure and/or the emission current lowers the voltage drop, however, for the same initial Cs pressure and emission conditions, the voltage drop in the I-V mode is usually lower than that during current modulation. As long as the discharge current is kept lower that the.emission current, the voltage drop during stable current modulation could be as low as 3 V.

  15. Ozonation of sunflower oils: impact of experimental conditions on the composition and the antibacterial activity of ozonized oils.

    PubMed

    Moureu, Sophie; Violleau, Frédéric; Ali Haimoud-Lekhal, Djamila; Calmon, Anne

    2015-02-01

    Ozone can react with vegetable oils to produce ozonized oils which have antimicrobial properties and can be used in dermatology. The aim of this study was to evaluate the influence of ozonation conditions and of the initial fatty acid composition on iodine index (II), peroxide index (IP), acidity value (AV) of ozonized sunflower oils. The antibacterial activity of these products against the three bacterial strains that are more often involved in mastitis (Staphylococcus aureus, Escherichia coli and Streptococcus uberis) was also evaluated. In that purpose, two different sunflower oils have been studied: a "classical" oil (55% linoleic acid, 35% oleic acid) and a "high oleic" oil (90% oleic acid). Both were ozonized with or without water during different times (from 1 to 7 h). Results show that the addition of water has a direct impact on the increase in IP (up to 2600 meq of active oxygen/kg of oil with water and 430 without) and AV but does not influence the kinetic of the decrease in II. Minimal inhibitory concentrations were ranging from 1.25 to 40 mg/mL and the antibacterial activity of oils ozonized with water was better than the one of oils ozonized alone. These results are an open door to new applications of ozonized oils.

  16. The use of FDTD in establishing in vitro experimentation conditions representative of lifelike cell phone radiation on the spermatozoa.

    PubMed

    Mouradi, Rand; Desai, Nisarg; Erdemir, Ahmet; Agarwal, Ashok

    2012-01-01

    Recent studies have shown that exposing human semen samples to cell phone radiation leads to a significant decline in sperm parameters. In daily living, a cell phone is usually kept in proximity to the groin, such as in a trouser pocket, separated from the testes by multiple layers of tissue. The aim of this study was to calculate the distance between cell phone and semen sample to set up an in vitro experiment that can mimic real life conditions (cell phone in trouser pocket separated by multiple tissue layers). For this reason, a computational model of scrotal tissues was designed by considering these separating layers, the results of which were used in a series of simulations using the Finite Difference Time Domain (FDTD) method. To provide an equivalent effect of multiple tissue layers, these results showed that the distance between a cell phone and semen sample should be 0.8 cm to 1.8 cm greater than the anticipated distance between a cell phone and the testes.

  17. The placental pursuit for an adequate oxidant balance between the mother and the fetus

    PubMed Central

    Herrera, Emilio A.; Krause, Bernardo; Ebensperger, German; Reyes, Roberto V.; Casanello, Paola; Parra-Cordero, Mauro; Llanos, Anibal J.

    2014-01-01

    The placenta is the exchange organ that regulates metabolic processes between the mother and her developing fetus. The adequate function of this organ is clearly vital for a physiologic gestational process and a healthy baby as final outcome. The umbilico-placental vasculature has the capacity to respond to variations in the materno-fetal milieu. Depending on the intensity and the extensity of the insult, these responses may be immediate-, mediate-, and long-lasting, deriving in potential morphostructural and functional changes later in life. These adjustments usually compensate the initial insults, but occasionally may switch to long-lasting remodeling and dysfunctional processes, arising maladaptation. One of the most challenging conditions in modern perinatology is hypoxia and oxidative stress during development, both disorders occurring in high-altitude and in low-altitude placental insufficiency. Hypoxia and oxidative stress may induce endothelial dysfunction and thus, reduction in the perfusion of the placenta and restriction in the fetal growth and development. This Review will focus on placental responses to hypoxic conditions, usually related with high-altitude and placental insufficiency, deriving in oxidative stress and vascular disorders, altering fetal and maternal health. Although day-to-day clinical practice, basic and clinical research are clearly providing evidence of the severe impact of oxygen deficiency and oxidative stress establishment during pregnancy, further research on umbilical and placental vascular function under these conditions is badly needed to clarify the myriad of questions still unsettled. PMID:25009498

  18. Experimental investigation and planetary implications of the stability of clathrate hydrates in aqueous solution at icy satellite conditions

    NASA Astrophysics Data System (ADS)

    Dunham, M.; Choukroun, M.; Barmatz, M.; Hodyss, R. P.; Smythe, W. D.

    2012-12-01

    Clathrate hydrates consist of hydrogen-bonded water molecules forming cages in which gas molecules are trapped individually. They are among the favored volatile reservoirs in solar system bodies, and are expected to play an important role in many processes: accretion of volatiles in planetesimals, outgassing on Titan, Enceladus, and comets. Their insulating thermal properties and high mechanical strength also bear important implications for understanding the evolution of icy satellites like Europa. However, the conditions allowing for their formation and/or their dissociation and the release of volatiles to the atmosphere (Titan) or the plumes (Enceladus) are still poorly understood. This is mainly because of a lack of knowledge on the stability of mixed clathrate hydrates in presence of anti-freeze agents such as ammonia. We have developed a high-pressure cryogenic calorimeter to address this deficiency in the literature. This liquid nitrogen - cooled Setaram BT2.15 calorimeter is located at the JPL Ice Physics Laboratory. The temperature range achievable with this instrument is 77-473 K. This calorimeter uses Calvet elements (3D arrays of thermocouples) to measure the heat flow required to follow a predefined heating rate within a sample and a reference cell with a resolution of 0.1 μW. A gas handling system has been designed and fabricated in house to reach pressures up to 100 bars, corresponding to several km depth in icy satellites. The thermodynamic properties of CO2 and CH4 clathrates with ammonia are under investigation, and the results will be used to constrain a statistical thermodynamic model of clathrates for applications to planetary environments. Preliminary results will be shown at the meeting. This work has been conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. Support from the Minnesota Space Grant Consortium, the NASA Outer Planets Research program, and government sponsorship are gratefully

  19. Effects of ischaemic post-conditioning on the early and late testicular damage after experimental testis ischaemia-reperfusion.

    PubMed

    Minutoli, L; Irrera, N; Squadrito, F; Marini, H; Nicotina, P A; Arena, S; Romeo, C; Antonuccio, P; Altavilla, D

    2014-01-01

    Ischaemic post-conditioning (IPostC) might represent an innovative surgical approach to protect organs from ischaemia and reperfusion (I/R) injury. We investigated the molecular mechanisms underlying the contrasting effects of IPostC on the early and late damage induced by testicular I/R injury. Testis I/R was induced by occluding the right testicular vessels using a clip. Male rats were divided into the following groups: sham, I/R and I/R + IPostC. In the I/R group, the clip was removed after 60 min of ischaemia, and reperfusion was allowed for 30 min, 1 and 30 days. In the I/R + IPostC group, three cycles of 30-sec reperfusion and 30-sec ischaemia were performed after 60 min of ischaemia and then reperfusion followed up for 30 min, 1 and 30 days. Following 30-min reperfusion, there was an increase in mitogen-activated protein kinases (MAPKs) in I/R rats; after 1 day of reperfusion, interleukin-6, tumour necrosis factor-α and nuclear factor-κB (NF-κB) expression were significantly increased; IκB-α expression reduced; and a marked damage in both testes was observed. IPostC inhibited MAPKs, cytokines and NF-κB expression, augmented IκB-α expression and decreased histological damage in testes subjected to I/R. After 30 days of reperfusion, I/R injury activated the apoptosis machinery, caused severe histological damage and reduced spermatogenic activity. By contrast, IPostC did not modify the apoptotic markers, the histological alterations as well as spermatogenic activity following 30 days of reperfusion. Our data demonstrate that IPostC protects the testis from the early damage induced by I/R injury, but it does not protect against the late damage.

  20. Experimental study on evaporation from seasonally frozen soils under various water, solute and groundwater conditions in Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Wu, Mousong; Huang, Jiesheng; Wu, Jingwei; Tan, Xiao; Jansson, Per-Erik

    2016-04-01

    Soil freezing and thawing significantly impact water balance in cold regions. To improve estimations of evaporation from seasonally frozen and saline soils, field experiments representing various water and solute conditions were conducted during a 5-month-period in Inner Mongolia, China. A mass balance method was used to estimate evaporation from frost tubes (5.5 × 300 cm) with treatments combining three solute contents (0.2%, 0.4%, and 0.6% g g-1 dry soil) with three initial groundwater table depth (GWTDs) (2.0, 1.5, and 1.0 m). The dynamics of water, heat and solute transport in the frost tubes and in field plots were also investigated. Seasonal changes in evaporation rates were observed during soil freezing/thawing periods. Low evaporation rates were maintained when the soil was deeply frozen (e.g., in P3), and relatively higher values occurred at the beginning and the end of the experiments (e.g., in P1 and P5). The cumulative evaporation amount increased with an increase in initial solute content and declined with a lowering of the initial GWTDs. Solute accumulation with water in the surface layer during freezing decreased the osmotic potential in soil, resulting in obvious freezing point depressions and higher liquid water contents in the uppermost layer of soil. During the soil thawing periods, no evidence of any control of water availability on evaporation was noticed, although the surface soil contained large amounts of water. This study has led to an improved understanding of the coupled effects of water, heat and solute on evaporation from seasonally frozen saline soils and also has important implications for water and energy balance studies in cold regions.

  1. Conditional cash transfers and the double burden of malnutrition among children in Colombia: a quasi-experimental study.

    PubMed

    Lopez-Arana, Sandra; Avendano, Mauricio; Forde, Ian; van Lenthe, Frank J; Burdorf, Alex

    2016-05-28

    Conditional cash-transfer (CCT) programmes have been shown to improve the nutritional and health status of children from poor families. However, CCT programmes may have unintended and not fully known consequences by increasing the risk of overweight and obesity. We examined the impact of Familias en Acción (FA), a large CCT programme in Colombia, on the double burden of malnutrition among pre-school and school-aged children. Height and weight were measured before programme enrolment and during follow-ups in 1290 children from thirty-one treatment municipalities, being compared with 1584 children from sixty-two matched control municipalities. We used a difference-in-differences approach to evaluate the effect of FA on children's stunting, BMI z-scores, thinness, overweight and obesity, controlling for individual and municipality-level confounders. At baseline, the prevalences of stunting and overweight were 30·3 and 15·4 %, respectively, in treatment municipalities and 27·9 and 17·4 % in control municipalities. FA was associated with reduced odds of thinness (OR 0·26; 95 % CI 0·09, 0·75) and higher BMI-for-age z-scores (BMI z-scores) (β 0·14; 95 % CI 0·00, 0·27; P<0·05), although the latter was of small clinical significance. The prevalence of stunting, overweight and obesity decreased over time, but the effect of FA on these outcomes was not significant. The CCT programme in Colombia reduced the odds of thinness, but had no effect on stunting, a more prevalent outcome. The FA programme had no effect on overweight or obesity, although BMI z-scores were higher for children under treatment, raising the possibility of an increase of small clinical significance on BMI among pre-school and school-aged children.

  2. Determination of free concentration of piroxicam and naproxen in plasma. The influence of experimental conditions in equilibrium dialysis.

    PubMed

    Hundal, O; Rugstad, H E

    1991-01-01

    An equilibrium dialysis method was established in order to investigate possible relationships between free drug concentrations of piroxicam and naproxen and clinical events. Therefore the influence of variations in pH, phosphate concentration and sodium azide concentration of the dialysis buffer on the free concentrations of piroxicam and naproxen was investigated. Piroxicam was found to have a pH-dependent protein binding. Therefore a good control of pH during the dialysis process is necessary. This has been achieved by increasing the buffer capacity of the dialysis buffer, by adding an antibacterial agent to the dialysis buffer and by cleansing the dialysis cells with 70% ethanol before use to prevent bacterial growth. Addition of 0.03% sodium azide as an antibacterial agent and the use of a 0.09 mol/l phosphate buffer gave good pH control. A method to correct for deviations of pH in measurements of free concentrations of piroxicam by a simple mathematical correction has been found. As naproxen was found to have a protein binding independent of pH, a pH-correction is not necessary for this drug. Standardized conditions in determination of protein binding of drugs by equilibrium dialysis are important, as composition of the dialysis buffer and pH of plasma compartment at equilibrium may influence the free concentration measurements. Comparisons of data from experiments using different methods are therefore difficult; the importance of pH-control is stressed. With the methods used in the present investigation, equilibrium dialysis in connection with HPLC, the coefficients of variation for piroxicam and naproxen free concentrations are 5.5% and 7.4%, respectively.

  3. SPINE: SParse eIgengene NEtwork linking gene expression clusters in Dehalococcoides mccartyi to perturbations in experimental conditions

    SciTech Connect

    Mansfeldt, Cresten B.; Logsdon, Benjamin A.; Debs, Garrett E.; Richardson, Ruth E.; Mande, Shekhar C.

    2015-02-25

    We present a statistical model designed to identify the effect of experimental perturbations on the aggregate behavior of the transcriptome expressed by the bacterium Dehalococcoides mccartyi strain 195. Strains of Dehalococcoides are used in sub-surface bioremediation applications because they organohalorespire tetrachloroethene and trichloroethene (common chlorinated solvents that contaminate the environment) to non-toxic ethene. However, the biochemical mechanism of this process remains incompletely described. Additionally, the response of Dehalococcoides to stress-inducing conditions that may be encountered at field-sites is not well understood. The constructed statistical model captured the aggregate behavior of gene expression phenotypes by modeling the distinct eigengenes of 100 transcript clusters, determining stable relationships among these clusters of gene transcripts with a sparse network-inference algorithm, and directly modeling the effect of changes in experimental conditions by constructing networks conditioned on the experimental state. Based on the model predictions, we discovered new response mechanisms for DMC, notably when the bacterium is exposed to solvent toxicity. The network identified a cluster containing thirteen gene transcripts directly connected to the solvent toxicity condition. Transcripts in this cluster include an iron-dependent regulator (DET0096-97) and a methylglyoxal synthase (DET0137). To validate these predictions, additional experiments were performed. Continuously fed cultures were exposed to saturating levels of tetrachloethene, thereby causing solvent toxicity, and transcripts that were predicted to be linked to solvent toxicity were monitored by quantitative reverse-transcription polymerase chain reaction. Twelve hours after being shocked with saturating levels of tetrachloroethene, the control transcripts (encoding for a key hydrogenase and the 16S rRNA) did not significantly change. By contrast

  4. Experimental investigation of effect of surface gravity waves and spray on heat and momentum flux at strong wind conditions

    NASA Astrophysics Data System (ADS)

    Troitskaya, Yuliya; Sergeev, Daniil; Vdovin, Maxim; Kandaurov, Alexander; Ermakova, Olga; Kazakov, Vassily

    2015-04-01

    The most important characteristics that determine the interaction between atmosphere and ocean are fluxes of momentum, heat and moisture. For their parameterization the dimensionless exchange coefficients (the surface drag coefficient CD and the heat transfer coefficient or the Stanton number CT) are used. Numerous field and laboratory experiments show that CD increases with increasing wind speed at moderate and strong wind, and as it was shows recently CD decreases at hurricane wind speed. Waves are known to increase the sea surface resistance due to enhanced form drag, the sea spray is considered as a possible mechanism of the 'drag reduction' at hurricane conditions. The dependence of heat transfer coefficient CD on the wind speed is not so certain and the role of the mechanism associated with the wave disturbances in the mass transfer is not completely understood. Observations and laboratory data show that this dependence is weaker than for the CD, and there are differences in the character of the dependence in different data sets. The purpose of this paper is investigation of the effect of surface waves on the turbulent exchange of momentum and heat within the laboratory experiment, when wind and wave parameters are maintained and controlled. The effect of spray on turbulent exchange at strong winds is also estimated. A series of experiments to study the processes of turbulent exchange of momentum and heat in a stably stratified temperature turbulent boundary layer air flow over waved water surface were carried out at the Wind - wave stratified flume of IAP RAS, the peculiarity of this experiment was the option to change the surface wave parameters regardless of the speed of the wind flow in the channel. For this purpose a polyethylene net with the variable depth (0.25 mm thick and a cell of 1.6 mm × 1.6mm) has been stretched along the channel. The waves were absent when the net was located at the level of the undisturbed water surface, and had maximum

  5. Experimental study of ethylene counterflow diffusion flames perturbed by trace amounts of jet fuel and jet fuel surrogates under incipiently sooting conditions

    SciTech Connect

    Jahangirian, Saeed; Gomez, Alessandro; McEnally, Charles S.

    2009-09-15

    The structure of an ethylene counterflow diffusion flame doped with 2000 ppm on a molar basis of either jet fuel or two jet fuel surrogates is studied under incipient sooting conditions. The doped flames have identical stoichiometric mixture fractions (z{sub f} = 0.18) and strain rates (a = 92 s{sup -1}), resulting in a well-defined and fixed temperature/time history for all of the flames. Gas samples are extracted from the flame with quartz microprobes for subsequent GC/MS analysis. Profiles of critical fuel decomposition products and soot precursors, such as benzene and toluene, are compared. The data for C7-C12 alkanes are consistent with typical decomposition of large alkanes with both surrogates showing good qualitative agreement with jet fuel in their pyrolysis trends. Olefins are formed as the fuel alkanes decompose, with agreement between the surrogates and jet fuel that improves for small alkenes, probably because of an increase in kinetic pathways which makes the specifics of the alkane structure less important. Good agreement between jet fuel and the surrogates is found with respect to critical soot precursors such as benzene and toluene. Although the six-component Utah/Yale surrogate performs better than the Aachen surrogate, the latter performs adequately and retains the advantage of simplicity, since it consists of only two components. The acetylene profiles present a unique multimodal behavior that can be attributed to acetylene's participation in early stages of formation of soot precursors, such as benzene and other large pyrolysis products, as well as in the surface growth of soot particles. (author)

  6. Ultra-high performance fibre-reinforced concrete under impact: experimental analysis of the mechanical response in extreme conditions and modelling using the Pontiroli, Rouquand and Mazars model.

    PubMed

    Erzar, Benjamin; Pontiroli, Christophe; Buzaud, Eric

    2017-01-28

    To evaluate the vulnerability of ultra-high performance fibre-reinforced concrete (UHPFRC) infrastructure to rigid projectile penetration, over the last few years CEA-Gramat has led an experimental and numerical research programme in collaboration with French universities. During the penetration process, concrete is subjected to extreme conditions of pressure and strain rate. Plasticity mechanisms as well as dynamic tensile and/or shear damage are activated during the tunnelling phase and the cratering of the concrete target. Each mechanism has been investigated independently at the laboratory scale and the role of steel fibres especially has been analysed to understand their influence on the macroscopic behaviour. To extend the experimental results to the structural scale, penetration tests on UHPFRC slabs have been conducted by CEA-Gramat. The analysis of this dataset combined with material characterization experiments allows the role of steel fibres to be identified in the different plasticity and damage mechanisms occurring during penetration. In parallel, some improvements have been introduced into the concrete model developed by Pontiroli, Rouquand and Mazars (PRM model), especially to take into account the contribution made by the fibres in the tensile fracture process. After a primary phase of validation, the capabilities of the PRM model are illustrated by performing numerical simulations of projectile penetration into UHPFRC concrete structures.This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  7. Ultra-high performance fibre-reinforced concrete under impact: experimental analysis of the mechanical response in extreme conditions and modelling using the Pontiroli, Rouquand and Mazars model

    NASA Astrophysics Data System (ADS)

    Erzar, Benjamin; Pontiroli, Christophe; Buzaud, Eric

    2017-01-01

    To evaluate the vulnerability of ultra-high performance fibre-reinforced concrete (UHPFRC) infrastructure to rigid projectile penetration, over the last few years CEA-Gramat has led an experimental and numerical research programme in collaboration with French universities. During the penetration process, concrete is subjected to extreme conditions of pressure and strain rate. Plasticity mechanisms as well as dynamic tensile and/or shear damage are activated during the tunnelling phase and the cratering of the concrete target. Each mechanism has been investigated independently at the laboratory scale and the role of steel fibres especially has been analysed to understand their influence on the macroscopic behaviour. To extend the experimental results to the structural scale, penetration tests on UHPFRC slabs have been conducted by CEA-Gramat. The analysis of this dataset combined with material characterization experiments allows the role of steel fibres to be identified in the different plasticity and damage mechanisms occurring during penetration. In parallel, some improvements have been introduced into the concrete model developed by Pontiroli, Rouquand and Mazars (PRM model), especially to take into account the contribution made by the fibres in the tensile fracture process. After a primary phase of validation, the capabilities of the PRM model are illustrated by performing numerical simulations of projectile penetration into UHPFRC concrete structures. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  8. Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode

    NASA Astrophysics Data System (ADS)

    Li, Lee; Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang

    2014-01-01

    Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.

  9. Geochemical Data for Upper Mineral Creek, Colorado, Under Existing Ambient Conditions and During an Experimental pH Modification, August 2005

    USGS Publications Warehouse

    Runkel, Robert L.; Kimball, Briant A.; Steiger, Judy I.; Walton-Day, Katherine

    2009-01-01

    Mineral Creek, an acid mine drainage stream in south-western Colorado, was the subject of a water-quality study that employed a paired synoptic approach. Under the paired synoptic approach, two synoptic sampling campaigns were conducted on the same study reach. The initial synoptic campaign, conducted August 22, 2005, documented stream-water quality under existing ambient conditions. A second synoptic campaign, conducted August 24, 2005, documented stream-water quality during a pH-modification experiment that elevated the pH of Mineral Creek. The experimental pH modification was designed to determine the potential reductions in dissolved constituent concentrations that would result from the implementation of an active treatment system for acid mine drainage. During both synoptic sampling campaigns, a solution containing lithium bromide was injected continuously to allow for the calculation of streamflow using the tracer-dilution method. Synoptic water-quality samples were collected from 30 stream sites and 11 inflow locations along the 2-kilometer study reach. Data from the study provide spatial profiles of pH, concentration, and streamflow under both existing and experimentally-altered conditions. This report presents the data obtained August 21-24, 2005, as well as the methods used for sample collection and data analysis.

  10. Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode

    SciTech Connect

    Li, Lee Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang

    2014-01-14

    Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.

  11. Improved ASTM G72 Test Method for Ensuring Adequate Fuel-to-Oxidizer Ratios

    NASA Technical Reports Server (NTRS)

    Juarez, Alfredo; Harper, Susana Tapia

    2016-01-01

    The ASTM G72/G72M-15 Standard Test Method for Autogenous Ignition Temperature of Liquids and Solids in a High-Pressure Oxygen-Enriched Environment is currently used to evaluate materials for the ignition susceptibility driven by exposure to external heat in an enriched oxygen environment. Testing performed on highly volatile liquids such as cleaning solvents has proven problematic due to inconsistent test results (non-ignitions). Non-ignition results can be misinterpreted as favorable oxygen compatibility, although they are more likely associated with inadequate fuel-to-oxidizer ratios. Forced evaporation during purging and inadequate sample size were identified as two potential causes for inadequate available sample material during testing. In an effort to maintain adequate fuel-to-oxidizer ratios within the reaction vessel during test, several parameters were considered, including sample size, pretest sample chilling, pretest purging, and test pressure. Tests on a variety of solvents exhibiting a range of volatilities are presented in this paper. A proposed improvement to the standard test protocol as a result of this evaluation is also presented. Execution of the final proposed improved test protocol outlines an incremental step method of determining optimal conditions using increased sample sizes while considering test system safety limits. The proposed improved test method increases confidence in results obtained by utilizing the ASTM G72 autogenous ignition temperature test method and can aid in the oxygen compatibility assessment of highly volatile liquids and other conditions that may lead to false non-ignition results.

  12. Effects of direct-fed microbial supplementation on broiler performance, intestinal nutrient transport and integrity under experimental conditions with increased microbial challenge.

    PubMed

    Murugesan, G R; Gabler, N K; Persia, M E

    2014-02-01

    1. The effects of Aspergillus oryzae- and Bacillus subtilis-based direct-fed microbials (DFM) were investigated on the performance, ileal nutrient transport and intestinal integrity of broiler chickens, raised under experimental conditions, with increased intestinal microbial challenge. 2. The first study was a 3 × 2 factorial experiment, with 3 dietary treatments (control (CON), CON + DFM and CON + antibiotic growth promoter) with and without challenge. Chicks were fed experimental diets from 1 to 28 d, while the challenge was provided by vaccinating with 10 times the normal dose of commercial coccidial vaccine on d 9. In a second experiment, two groups of 1 d-old broilers, housed on built-up litter (uncleaned from two previous flocks), were fed the same CON and CON + DFM diets from 1 to 21 d. 3. The challenge in the first experiment reduced performance, but no differences were observed among dietary treatments from 8 to 28 d. The challenge reduced the ileal epithelial flux for D-glucose, L-lysine, DL-methionine and phosphorus on d 21. Epithelial flux for D-glucose, L-lysine and DL-methionine were increased by DFM. Ileal trans-epithelial electrical resistance (TER) was increased in challenged broilers fed DFM, although this was not observed in unchallenged birds as indicated by a significant interaction. 4. Ileal mucin mRNA expression and colon TER were increased, and colon endotoxin permeability was reduced by DFM on d 21 in the second experiment. 5. It was concluded that the addition of DFM in the diet improved the intestinal integrity of broiler chickens raised under experimental conditions designed to provide increased intestinal microbial challenge.

  13. Using a Péclet number for the translocation of a polymer through a nanopore to tune coarse-grained simulations to experimental conditions

    NASA Astrophysics Data System (ADS)

    de Haan, Hendrick W.; Sean, David; Slater, Gary W.

    2015-02-01

    Coarse-grained simulations are often employed to study the translocation of DNA through a nanopore. The majority of these studies investigate the translocation process in a relatively generic sense and do not endeavor to match any particular set of experimental conditions. In this manuscript, we use the concept of a Péclet number for translocation, Pt, to compare the drift-diffusion balance in a typical experiment vs a typical simulation. We find that the standard coarse-grained approach overestimates diffusion effects by anywhere from a factor of 5 to 50 compared to experimental conditions using double stranded DNA (dsDNA). By defining a Péclet control parameter, λ , we are able to correct this and tune the simulations to replicate the experimental Pt (for dsDNA and other scenarios). To show the effect that a particular Pt can have on the dynamics of translocation, we perform simulations across a wide range of Pt values for two different types of driving forces: a force applied in the pore and a pulling force applied to the end of the polymer. As Pt brings the system from a diffusion dominated to a drift dominated regime, a variety of effects are observed including a non-monotonic dependence of the translocation time τ on Pt and a steep rise in the probability of translocating. Comparing the two force cases illustrates the impact of the crowding effects that occur on the trans side: a non-monotonic dependence of the width of the τ distributions is obtained for the in-pore force but not for the pulling force.

  14. Nematode community shifts in response to experimental warming and canopy conditions are associated with plant community changes in the temperate-boreal forest ecotone.

    PubMed

    Thakur, Madhav Prakash; Reich, Peter B; Fisichelli, Nicholas A; Stefanski, Artur; Cesarz, Simone; Dobies, Tomasz; Rich, Roy L; Hobbie, Sarah E; Eisenhauer, Nico

    2014-06-01

    Global climate warming is one of the key forces driving plant community shifts, such as range shifts of temperate species into boreal forests. As plant community shifts are slow to observe, ecotones, boundaries between two ecosystems, are target areas for providing early evidence of ecological responses to warming. The role of soil fauna is poorly explored in ecotones, although their positive and negative effects on plant species can influence plant community structure. We studied nematode communities in response to experimental warming (ambient, +1.7, +3.4 °C) in soils of closed and open canopy forest in the temperate-boreal ecotone of Minnesota, USA and calculated various established nematode indices. We estimated species-specific coverage of understory herbaceous and shrub plant species from the same experimental plots and tested if changes in the nematode community are associated with plant cover and composition. Individual nematode trophic groups did not differ among warming treatments, but the ratio between microbial-feeding and plant-feeding nematodes increased significantly and consistently with warming in both closed and open canopy areas and at both experimental field sites. The increase in this ratio was positively correlated with total cover of understory plant species, perhaps due to increased predation pressure on soil microorganisms causing higher nutrient availability for plants. Multivariate analyses revealed that temperature treatment, canopy conditions and nematode density consistently shaped understory plant communities across experimental sites. Our findings suggest that warming-induced changes in nematode community structure are associated with shifts in plant community composition and productivity in the temperate-boreal forest ecotones.

  15. Adequate antigen availability: a key issue for novel approaches to tumor vaccination and tumor immunotherapy.

    PubMed

    Accolla, Roberto S; Tosi, Giovanna

    2013-03-01

    A crucial parameter for activation of the anti-tumor immune response is an adequate antigen availability (AAA) defined here as the optimal tumor antigen dose and related antigen processing and MHC-II-restricted presentation necessary to efficiently trigger tumor-specific TH cells. We will discuss two distinct experimental systems: a) a preventive anti-tumor vaccination system; b) a therapy-induced anti-tumor vaccination approach. In the first case tumor cells are rendered constitutively MHC-II+ by transfecting them with the MHC-II transcriptional activator CIITA. Here AAA is generated by the function of tumor's newly expressed MHC-II molecules to present tumor-associated antigens to tumor-specific TH cells. In the second case, AAA is generated by treating established tumors with neovasculature-targeted TNFα. In conjuction with Melphalan, targeted TNFα delivery produces extensive areas of tumor necrosis that generate AAA capable of optimally activate tumor-specific TH cells which in turn activate CTL immune effectors. In both experimental systems tumor rejection and persistent and long-lived TH cell anti-tumor memory, responsible of defending the animals from subsequent challenges with tumor cells, are achieved. Based on these and other investigators' results we propose that AAA is a key element for triggering adaptive immune functions resulting in subversion from a pro-tumor to an anti-tumor microenvironment, tumor rejection and acquisition of anti-tumor immune memory. Hypotheses of neuro-immune networks involved in these approaches are discussed. These considerations are important also for the comprehension of how chemotherapy and/or radiation therapies may help to block and/or to eradicate the tumor and for the construction of suitable anti-tumor vaccine strategies.

  16. Experimental definition of microclimatic conditions based on water transfer and porous media properties for the conservation of prehistoric constructions: Cueva Pintada at Galdar, Gran Canaria, Spain

    NASA Astrophysics Data System (ADS)

    Benavente, D.; Cañaveras, J. C.; Cuezva, S.; Laiz, L.; Sanchez-Moral, S.

    2009-02-01

    Microclimatic parameters and natural materials were studied in order to assess conservation of the cave complex at Galdar, Gran Canaria. Based on the microclimatic data, experimental simulations were carried out to quantify water retention capacity and water vapour transport kinetics under continuously changing extreme temperatures and relative humidity values. The behaviour of natural construction materials is greatly influenced by changes in thermo-hygrometric conditions and is linked to pore structure. The host rock has a complex porous media: high porosity and polymodal pore size distribution, where the smallest pores contribute to water condensation, whilst large pores lead to high water absorption rates. The axial compressive strength of the host-rock decreases between 30 and 70% at water saturation. Stuccos covering cave wall paintings are formed by clay minerals, mainly smectites. These clay minerals cover a large specific surface area, which leads to a high capacity for water condensation and retention. It is also shown that neither water condensation nor vapour transport are noticeably modified by the presence of stucco on the host-rock when rapid, highly variable changes occur in environmental conditions if large shrinkage cracks are present. Results show that safe threshold microclimatic conditions can be found below 75% RH in the natural temperature range and that slight variations in temperature and relative humidity do not modify durability properties.

  17. Experimental investigations of uncovered-bundle heat transfer and two-phase mixture-level swell under high-pressure low heat-flux conditions. [PWR

    SciTech Connect

    Anklam, T. M.; Miller, R. J.; White, M. D.

    1982-03-01

    Results are reported from a series of uncovered-bundle heat transfer and mixture-level swell tests. Experimental testing was performed at Oak Ridge National Laboratory in the Thermal Hydraulic Test Facility (THTF). The THTF is an electrically heated bundle test loop configured to produce conditions similar to those in a small-break loss-of-coolant accident. The objective of heat transfer testing was to acquire heat transfer coefficients and fluid conditions in a partially uncovered bundle. Testing was performed in a quasi-steady-state mode with the heated core 30 to 40% uncovered. Linear heat rates varied from 0.32 to 2.22 kW/m.rod (0.1 to 0.68 kW/ft.rod). Under these conditions peak clad temperatures in excess of 1050 K (1430/sup 0/F) were observed, and total heat transfer coefficients ranged from 0.0045 to 0.037 W/cm/sup 2/.K (8 to 65 Btu/h.ft/sup 2/./sup 0/F). Spacer grids were observed to enhance heat transfer at, and downstream of, the grid. Radiation heat transfer was calculated to account for as much as 65% of total heat transfer in low-flow tests.

  18. Experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO{sub 2} lasers under conditions of minimal roughness

    SciTech Connect

    Golyshev, A A; Malikov, A G; Orishich, A M; Shulyatyev, V B

    2014-10-31

    The results of an experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO{sub 2} lasers are generalised. The dependence of roughness of the cut surface on the cutting parameters is investigated, and the conditions under which the surface roughness is minimal are formulated. It is shown that for both types of lasers these conditions can be expressed in the same way in terms of the dimensionless variables – the Péclet number Pe and the output power Q of laser radiation per unit thickness of the cut sheet – and take the form of the similarity laws: Pe = const, Q = const. The optimal values of Pe and Q are found. We have derived empirical expressions that relate the laser power and cutting speed with the thickness of the cut sheet under the condition of minimal roughness in the case of cutting by means of radiation from fibre and CO{sub 2} lasers. (laser technologies)

  19. Receptor-level interrelationships of amino acids and the adequate amino acid type hormones in Tetrahymena: a receptor evolution model.

    PubMed

    Csaba, G; Darvas, Z

    1986-01-01

    Histidine stimulates the phagocytosis of Tetrahymena to the same extent as histamine, and also stimulates its division, which histamine does not. Tyrosine and diiodotyrosine equally stimulate the growth of the Tetrahymena. Both amino acids inhibit the characteristic influence of the adequate amino acid hormone when added to Tetrahymena culture 72 h in advance of it. Primary interaction with diiodotyrosine and tyrosine notably increases the cellular growth rate. Histamine has a similar, although less notable effect than histidine. In the light of these experimental observations there is reason to postulate that the receptors of the amino acid hormones have developed from amino acid receptors.

  20. 9 CFR 2.40 - Attending veterinarian and adequate veterinary care (dealers and exhibitors).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... veterinary care (dealers and exhibitors). 2.40 Section 2.40 Animals and Animal Products ANIMAL AND PLANT... and Adequate Veterinary Care § 2.40 Attending veterinarian and adequate veterinary care (dealers and... veterinary care to its animals in compliance with this section. (1) Each dealer and exhibitor shall employ...