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Sample records for thermosyphon effect

  1. The geyser effect in a two-phase thermosyphon

    NASA Astrophysics Data System (ADS)

    Casarosa, C.; Latrofa, E.; Shelginskii, A.

    1983-06-01

    The geyser effect in a two-phase thermosyphon using water as the working fluid is investigated experimentally in order to provide a foundation for future theoretical work. It is shown that boiling in a two-phase syphon is a rather complex process and that at low pressures it involves the formation of bubbles of large diameter. The nucleation of individual bubbles occurs at large time intervals which, however, decrease when the specific thermal flux increases. An important conclusion is that the cyclic phenomenon observed in the thermosyphon can be studied in the evaporator using special methods for boiling-related phenomena.

  2. Titanium-Water Thermosyphon Gamma Radiation Effects and Results

    NASA Technical Reports Server (NTRS)

    Sanzi, James L.; Jaworske, Donald A.; Goodenow, Debra A.

    2012-01-01

    Titanium-water thermosyphons are being considered for use in heat rejection systems for fission power systems. Their proximity to the nuclear reactor will result in some exposure to gamma irradiation. Non-condensable gas formation from radiation may breakdown water over time and render a portion of the thermosyphon condenser inoperable. A series of developmental thermosyphons were operated at nominal operating temperature with accelerated gamma irradiation exposures on the same order of magnitude that is expected in eight years of heat rejection system operation. Temperature data were obtained during exposure at three locations on each thermosyphon; evaporator, condenser, and condenser end cap. Some non-condensable gas was evident, however thermosyphon performance was not affected because the non-condensable gas was compressed into the fill tube region at the top of the thermosyphon, away from the heat rejecting fin. The trend appeared to be an increasing amount of non-condensable gas formation with increasing gamma irradiation dose. Hydrogen is thought to be the most likely candidate for the non-condensable gas and hydrogen is known to diffuse through grain boundaries. Post-exposure evaluation of selected thermosyphons at temperature and in a vacuum chamber revealed that the non-condensable gas likely diffused out of the thermosyphons over a relatively short period of time. Further research shows a number of experimental and theoretical examples of radiolysis occurring through gamma radiation alone in pure water.

  3. The effect of geometry on the performance of the closed tube thermosyphon at low Rayleigh numbers

    NASA Astrophysics Data System (ADS)

    Lock, G. S. H.; Liu, Y.

    1989-06-01

    The results of an experimental investigation of heat transfer in the closed tube thermosyphon under laminar conditions are presented. Attention is focused on the effect of tube geometry when the Rayleigh number is low enough to create boundary layer, transitional and impeded flows. The data show that the length-diameter ratio and heated-cooled length ratio both have a monotonic effect on the heat transfer rate, the former being the greater. Results are presented for both air and water, with the latter tests including the effect of cooled wall temperatures low enough to produce an inverted flow in the cooled section.

  4. The Effect of Subcooling on the Flow and Heat Transfer Characteristics in a Two-Phase Loop Thermosyphon

    NASA Astrophysics Data System (ADS)

    Imura, Hideaki; Takeshita, Kazuhiro; Doi, Kyoji; Noda, Ken-Ichi

    A two-phase loop thermosyphon is used as a heat transfer device in an energy-saving heat transportation system and so forth, because it transports thermal energy without any external power supply such as a pump under a body force field. We previously performed a fundamental study on the flow and heat transfer characteristics in a two-phase loop thermosyphon installed with a single heated tube evaporator both experimentally and theoretically which was made under the condition of near saturation temperature of liquid in a reservoir. In the present study, the effects of liquid subcooling and the heat input on the circulation mass flow rates, pressure and temperature distributions, and heat transfer coefficients in the evaporator were examined experimentally using water, ethanol, benzene and Freon 113 as the working fluids. On the other hand, the circulation mass flow rates, pressure and temperature distributions were theoretically calculated and compared with the experimental results.

  5. Majorana Thermosyphon Prototype Experimental Setup

    SciTech Connect

    Reid, Douglas J.; Guzman, Anthony D.; Munley, John T.

    2011-08-01

    This report presents the experimental setup of Pacific Northwest National Laboratory’s MAJORANA DEMONSTRATOR thermosyphon prototype cooling system. A nitrogen thermosyphon prototype of such a system has been built and tested at PNNL. This document presents the experimental setup of the prototype that successfully demonstrated the heat transfer performance of the system.

  6. Thermosyphon Flooding Limits in Reduced Gravity Environments

    NASA Technical Reports Server (NTRS)

    Gibson, Marc A.; Jaworske, Donald A.; Sanzi, James L.; Ljubanovic, Damir

    2012-01-01

    Fission Power Systems have long been recognized as potential multi-kilowatt power solutions for lunar, Martian, and extended planetary surface missions. Current heat rejection technology associated with fission surface power systems has focused on titanium water thermosyphons embedded in carbon composite radiator panels. The thermosyphons, or wickless heat pipes, are used as a redundant and efficient way to spread the waste heat from the power conversion unit(s) over the radiator surface area where it can be rejected to space. It is well known that thermosyphon performance is reliant on gravitational forces to keep the evaporator wetted with the working fluid. One of the performance limits that can be encountered, if not understood, is the phenomenon of condenser flooding, otherwise known as evaporator dry out. This occurs when the gravity forces acting on the condensed fluid cannot overcome the shear forces created by the vapor escaping the evaporator throat. When this occurs, the heat transfer process is stalled and may not re-stabilize to effective levels without corrective control actions. The flooding limit in earth's gravity environment is well understood as experimentation is readily accessible, but when the environment and gravity change relative to other planetary bodies, experimentation becomes difficult. An innovative experiment was designed and flown on a parabolic flight campaign to achieve the Reduced Gravity Environments (RGE) needed to obtain empirical data for analysis. The test data is compared to current correlation models for validation and accuracy.

  7. Application of functionalized nanofluid in thermosyphon.

    PubMed

    Yang, Xue-Fei; Liu, Zhen-Hua

    2011-01-01

    A water-based functionalized nanofluid was made by surface functionalizing the ordinary silica nanoparticles. The functionalized nanofluid can keep long-term stability. and no sedimentation was observed. The functionalized nanofluid as the working fluid is applied in a thermosyphon to understand the effect of this special nanofluid on the thermal performance of the thermosyphon. The experiment was carried out under steady operating pressures. The same work was also explored for traditional nanofluid (consisting of water and the same silica nanoparticles without functionalization) for comparison. Results indicate that a porous deposition layer exists on the heated surface of the evaporator during the operating process using traditional nanofluid; however, no coating layer exists for functionalized nanofluid. Functionalized nanofluid can enhance the evaporating heat transfer coefficient, while it has generally no effect on the maximum heat flux. Traditional nanofluid deteriorates the evaporating heat transfer coefficient but enhances the maximum heat flux. The existence of the deposition layer affects mainly the thermal performance, and no meaningful nanofluid effect is found in the present study. PMID:21846362

  8. Application of functionalized nanofluid in thermosyphon

    PubMed Central

    2011-01-01

    A water-based functionalized nanofluid was made by surface functionalizing the ordinary silica nanoparticles. The functionalized nanofluid can keep long-term stability. and no sedimentation was observed. The functionalized nanofluid as the working fluid is applied in a thermosyphon to understand the effect of this special nanofluid on the thermal performance of the thermosyphon. The experiment was carried out under steady operating pressures. The same work was also explored for traditional nanofluid (consisting of water and the same silica nanoparticles without functionalization) for comparison. Results indicate that a porous deposition layer exists on the heated surface of the evaporator during the operating process using traditional nanofluid; however, no coating layer exists for functionalized nanofluid. Functionalized nanofluid can enhance the evaporating heat transfer coefficient, while it has generally no effect on the maximum heat flux. Traditional nanofluid deteriorates the evaporating heat transfer coefficient but enhances the maximum heat flux. The existence of the deposition layer affects mainly the thermal performance, and no meaningful nanofluid effect is found in the present study. PMID:21846362

  9. Heat transfer performance of two-phase closed thermosyphon with oxidized CNT/water nanofluids

    NASA Astrophysics Data System (ADS)

    Zeinali Heris, Saeed; Fallahi, Marjan; Shanbedi, Mehdi; Amiri, Ahmad

    2016-01-01

    In this paper, the effects of different acids on the thermal performance of oxidized carbon nanotubes (CNT)/water nanofluids in a two-phase closed thermosyphon were studied. The structures morphology and functionalization degree were studied concurrently. The results indicated that strong oxidants increased dispersivity of CNT in the nanofluids. In other words, as the number of COOH groups increased in the nanofluids, an upward trend was also observed in the thermal efficiency of the thermosyphon.

  10. Majorana Thermosyphon Prototype Experimental Results

    SciTech Connect

    Fast, James E.; Reid, Douglas J.; Aguayo Navarrete, Estanislao

    2010-12-17

    Objective The Majorana demonstrator will operate at liquid Nitrogen temperatures to ensure optimal spectrometric performance of its High Purity Germanium (HPGe) detector modules. In order to transfer the heat load of the detector module, the Majorana demonstrator requires a cooling system that will maintain a stable liquid nitrogen temperature. This cooling system is required to transport the heat from the detector chamber outside the shield. One approach is to use the two phase liquid-gas equilibrium to ensure constant temperature. This cooling technique is used in a thermosyphon. The thermosyphon can be designed so the vaporization/condensing process transfers heat through the shield while maintaining a stable operating temperature. A prototype of such system has been built at PNNL. This document presents the experimental results of the prototype and evaluates the heat transfer performance of the system. The cool down time, temperature gradient in the thermosyphon, and heat transfer analysis are studied in this document with different heat load applied to the prototype.

  11. Heat Transfer Characteristics in a Two-Phase Crank-Shape Closed Thermosyphon

    NASA Astrophysics Data System (ADS)

    Imura, Hideaki; Koito, Yasuhi

    This paper describes the heat transfer characteristics in a two-phase crank-shape closed thermosyphon. Usually, the thermosyphon is composed of an evaporator, an adiabatic section and a condenser arranged on a straight tube. However, a bent geometry of the thermosyphon is sometimes needed to use because of the limited space for the straight thermosyphon to be installed. Therefore, in the present study, the crank-shape thermosyphon is investigated on the heat transfer coefficients and the critical heat fluxes. The evaporator and the condenser are positioned vertically and the adiabatic section horizontally. The inside diameter of thermosyphon is 16 mm and each length of the evaporator and condenser is 500 mm. As a working fluid, water is used. The inside temperature (the adiabatic wall temperature) is varied from 40 to 80 °C. The distance between the centers of the vertical evaporator and condenser, i. e. , the offset length is varied from 220 to 620 mm, and the effect of the offset length on the heat transfer characteristics is presented.

  12. Natural convection in C-shaped thermosyphon

    SciTech Connect

    Mohamad, A.A.; Sezai, I.

    1997-08-29

    The present work is concerned with the numerical analysis of natural convection from a C-shaped thermosyphon. The system can be considered as a model for a Trombe wall in passive solar collectors as well as electronic cooling arrangements and it has geophysical applications. The effect of Rayleigh number (1 {times} 10{sup 3} to 1 {times} 10{sup 7}) and aspect ratios of 2.0, 4.0, 6.0, and 10.0 is investigated for a fixed Prandtl number (0.7). Local and average Nusselt numbers for heated and cold walls are discussed. Mass advected by the buoyancy force is calculated and presented for the range of investigated parameters. The flow pattern and isotherm distribution in the gap between the wall and cover plate are presented and discussed.

  13. Thermosyphon Flooding in Reduced Gravity Environments

    NASA Technical Reports Server (NTRS)

    Gibson, Marc Andrew

    2013-01-01

    An innovative experiment to study the thermosyphon flooding limits was designed and flown on aparabolic flight campaign to achieve the Reduced Gravity Environments (RGE) needed to obtainempirical data for analysis. Current correlation models of Faghri and Tien and Chung do not agreewith the data. A new model is presented that predicts the flooding limits for thermosyphons inearths gravity and lunar gravity with a 95 confidence level of +- 5W.

  14. Experiments and simulations on a thermosyphon solar collector with integrated storage

    NASA Astrophysics Data System (ADS)

    Toninelli, P.; Mariani, A.; Del, D., Col

    2015-11-01

    This paper deals with the thermal behaviour of a new type of flat solar collector that integrates the fluid storage tank. Often the main limitation of the solar thermosyphon installations is the prohibition to adopt external storage tanks due to their impact, especially for historical centres of particular architectural significance. To avoid this issue, a new system, that includes the collector and the storage, has been developed. This new apparatus works as a thermosyphon: it is possible to take advantage of the natural convection to avoid using a pump. Experimental tests have been conducted in such a collector with and without the absorbing plate. Furthermore, CFD simulations are reported to analyze in detail the dynamic thermal performance of the innovative solar collector and a good-agreement with the experimental tests has been found. Finally, both in numerical simulations and in experimental data the thermosyphon effect has been verified, obtaining the desired water temperature for domestic applications.

  15. Critical heat flux in a closed two-phase thermosyphon

    NASA Astrophysics Data System (ADS)

    Imura, H.; Sasaguchi, K.; Kozai, H.; Numata, S.

    1983-08-01

    An experimental study was made of critical heat flux in a closed two-phase thermosyphon. The effects of inside diameter, heated length, working liquid, fill charge and inside temperature on the critical heat flux were investigated. The present and previously-published experimental data were correlated with expressions already proposed by other investigators but the agreements were not good. Accordingly, a new correlating expression was derived. This expression agrees with the experimental data within + or - 30 percent accuracy. Also, discussion of the adequate fill charge is made.

  16. A passive thermosyphon heat exchanger for residential solar installations

    NASA Technical Reports Server (NTRS)

    Franklin, J. L.; Saaski, E. W.; Hankins, J. D.

    1977-01-01

    The paper details the development of a thermosyphon water-to-air heat exchanger for residential solar applications. Modeling techniques used in the analysis of thermosyphon performance are included, as well as test results from laboratory-scale experiments. In addition, a description of the initial full-scale prototype is presented, along with experimental test results. Present areas of development are discussed, with an economic comparison of thermosyphon and forced convection heating systems also being included.

  17. The Design of an Ultra-Low Background Thermosyphon for the Majorana Demonstrator

    SciTech Connect

    Aguayo Navarrete, Estanislao; Busch, Matthew; Daniels, Randy; Fast, James E.; Green, Matthew P.; Reid, Douglas J.

    2013-05-01

    The MAJORANA DEMONSTRATOR (MJD) is an ultra-low background neutrinoless double-beta decay (0???) experiment that will deploy up to 40 kg of high purity germanium detectors (HPGe). The goal of this experiment is to demonstrate the feasibility of building a detector array with less than 1 event/ton-year in a 4 keV region of interest around the 0??? signal. HPGe diodes, when used as ionizing radiation detectors, need to be maintained at a temperature close to that of liquid nitrogen (77 K). This work describes the R&D results of a cryogenic system capable of meeting the requirements of low background and the cooling capacity required to successfully operate such a detector system. The MJD germanium detector modules will operate at liquid nitrogen temperature to provide adequate cooling for a full range of HPGe impurity concentrations. This paper shows the experimental results obtained using a two-phase horizontal thermosyphon using liquid nitrogen as the MJD’s cooling system. The cold test shows that the proposed thermosyphon has sufficient cooling power to handle the heat load of an MJD module. Results for the temperature gradient across the thermosyphon, cooling capacity, and design considerations demonstrate that the thermosyphon can effectively remove the calculated heat load of each module of the experiment. The thermosyphon will be bolted to a cold plate from which detector strings will hang. The thermal conductivity of a mockup of the MJD bolted thermal joint is experimentally determined to be below 0.1 K/W.

  18. Titanium-Water Thermosyphon Gamma Radiation Exposure and Results

    NASA Technical Reports Server (NTRS)

    Sanzi, James, L.A; Jaworske, Donald, A.; Goodenow, Debra, A.

    2012-01-01

    Titanium-water thermosyphons are being considered for use in heat rejection systems for fission power systems. Their proximity to the nuclear reactor will result in some gamma irradiation. Noncondensable gas formation from radiation-induced breakdown of water over time may render portions of the thermosyphon condenser inoperable. A series of developmental thermosyphons were operated at nominal operating temperature under accelerated gamma irradiation, with exposures on the same order of magnitude as that expected in 8 years of heat rejection system operation. Temperature data were obtained during exposure at three locations on each thermosyphon: evaporator, condenser, and condenser end cap. Some noncondensable gas was evident; however, thermosyphon performance was not affected because the noncondensable gas was compressed into the fill tube region at the top of the thermosyphon, away from the heat rejecting fin. The trend appeared to be an increasing amount of noncondensable gas formation with increasing gamma irradiation dose. Hydrogen is thought to be the most likely candidate for the noncondensable gas and hydrogen is known to diffuse through grain boundaries. Post-exposure evaluation of one thermosyphon in a vacuum chamber and at temperature revealed that the noncondensable gas diffused out of the thermosyphon over a relatively short period of time. Further research shows a number of experimental and theoretical examples of radiolysis occurring through gamma radiation alone in pure water.

  19. Heat Transfer Characteristics in Crank-Shape Thermosyphons

    NASA Astrophysics Data System (ADS)

    Imura, Hedeaki; Koito, Yasushi

    A two-phase closed thermosyphon is applied to gas-to-gas heat exchangers, the cooling of heat generation devices, the melting of snow, the prevention from icing of water on roads and so on. Generally, straight tubes are used as the thermosyphon. However, because of the limited space for the straight thermosyphon to be installed, it is considered that a bent thermosyphon is enforced to employ. In response to this, fundamental experiments are conducted on the heat transfer characteristics in a two-phase crank shape closed thermosyphon, in which an evaporator and a condenser are vertically positioned, and a connecting adiabatic section is horizontal. Ethylene glycol aqueous solutions which have lower freezing points and hydrofluoroether 7100 and 7200 which do not contain chloride are used as the working fluids Heat transfer coefficients and critical heat fluxes in the thermosyphon are measured by changing the amount of charged working fluid (0.30,0.40,0.50 and 0.60 of the evaporator volume),the temperature of the adiabatic section (40,50,60,70 and 80°C) and heat flux (from 4.0 kW /m2 to critical). The experimental results are shown and compared with those taken using water as the working fluid.

  20. Convective heat transfer in a closed two-phase thermosyphon

    NASA Astrophysics Data System (ADS)

    Al-Ani, M. A.

    2014-08-01

    A numerical analysis of heat transfer processes and hydrodynamics in a two-phase closed thermosyphon in a fairly wide range of variation of governing parameters has been investigated. A mathematical model is formulated based on the laws of mass conservation, momentum and energy in dimensionless variables "stream function - vorticity vector velocity - temperature". The analysis of the modes of forced and mixed convection for different values of Reynolds number and heat flows in the evaporation zone, the possibility of using two-phase thermosyphon for cooling gas turbine blades, when the heat is coming from the turbine blades to the thermosyphon is recycled a secondary refrigerant has been studied with different values of the centrifugal velocity. Nusselet Number, streamlines, velocity, temperature fields and temperature profile has been calculated during the investigation.

  1. A thermosyphon heat pipe cooler for high power LEDs cooling

    NASA Astrophysics Data System (ADS)

    Li, Ji; Tian, Wenkai; Lv, Lucang

    2015-09-01

    Light emitting diode (LED) cooling is facing the challenge of high heat flux more seriously with the increase of input power and diode density. The proposed unique thermosyphon heat pipe heat sink is particularly suitable for cooling of high power density LED chips and other electronics, which has a heat dissipation potential of up to 280 W within an area of 20 mm Ă— 22 mm (>60 W/cm2) under natural air convection. Meanwhile, a thorough visualization investigation was carried out to explore the two phase flow characteristics in the proposed thermosyphon heat pipe. Implementing this novel thermosyphon heat pipe heat sink in the cooling of a commercial 100 W LED integrated chip, a very low apparent thermal resistance of 0.34 K/W was obtained under natural air convection with the aid of the enhanced boiling heat transfer at the evaporation side and the enhanced natural air convection at the condensation side.

  2. Thermosyphon Flooding in Reduced Gravity Environments Test Results

    NASA Technical Reports Server (NTRS)

    Gibson, Marc A.; Jaworske, Donald A.; Sanzi, Jim; Ljubanovic, Damir

    2013-01-01

    The condenser flooding phenomenon associated with gravity aided two-phase thermosyphons was studied using parabolic flights to obtain the desired reduced gravity environment (RGE). The experiment was designed and built to test a total of twelve titanium water thermosyphons in multiple gravity environments with the goal of developing a model that would accurately explain the correlation between gravitational forces and the maximum axial heat transfer limit associated with condenser flooding. Results from laboratory testing and parabolic flights are included in this report as part I of a two part series. The data analysis and correlations are included in a follow on paper.

  3. Investigation and Construction of a Thermosyphoning Solar Hot Water System

    ERIC Educational Resources Information Center

    Johnson, Harvey

    1978-01-01

    Describes how a thermosyphoning solar water heater capable of heating 110 kilogram of water to 80 degree Celsius and maintaining this temperature for 24 hours was constructed by four students in the fifth form of Sekolah Date Abdul Razak, Seremban, Malaysia in 1976. (HM)

  4. Application of silver nanofluid containing oleic acid surfactant in a thermosyphon economizer.

    PubMed

    Parametthanuwat, Thanya; Rittidech, Sampan; Pattiya, Adisak; Ding, Yulong; Witharana, Sanjeeva

    2011-01-01

    This article reports a recent study on the application of a two-phase closed thermosyphon (TPCT) in a thermosyphon for economizer (TPEC). The TPEC had three sections of equal size; the evaporator, the adiabatic section, and the condenser, of 250 mm × 250 mm × 250 mm (W × L × H). The TPCT was a steel tube of 12.7-mm ID. The filling ratios chosen to study were 30, 50, and 80% with respect to the evaporator length. The volumetric flow rates for the coolant (in the condenser) were 1, 2.5, and 5 l/min. Five working fluids investigated were: water, water-based silver nanofluid with silver concentration 0.5 w/v%, and the nanofluid (NF) mixed with 0.5, 1, and 1.5 w/v% of oleic acid (OA). The operating temperatures were 60, 70, and 80°C. Experimental data showed that the TPEC gave the highest heat flux of about 25 kW/m2 and the highest effectiveness of about 0.3 at a filling ratio of 50%, with the nanofluid containing 1 w/v% of OA. It was further found that the effectiveness of nanofluid and the OA containing nanofluids were superior in effectiveness over water in all experimental conditions came under this study. Moreover, the presence of OA had clearly contributed to raise the effectiveness of the nanofluid. PMID:21711856

  5. Application of silver nanofluid containing oleic acid surfactant in a thermosyphon economizer

    PubMed Central

    2011-01-01

    This article reports a recent study on the application of a two-phase closed thermosyphon (TPCT) in a thermosyphon for economizer (TPEC). The TPEC had three sections of equal size; the evaporator, the adiabatic section, and the condenser, of 250 mm × 250 mm × 250 mm (W × L × H). The TPCT was a steel tube of 12.7-mm ID. The filling ratios chosen to study were 30, 50, and 80% with respect to the evaporator length. The volumetric flow rates for the coolant (in the condenser) were 1, 2.5, and 5 l/min. Five working fluids investigated were: water, water-based silver nanofluid with silver concentration 0.5 w/v%, and the nanofluid (NF) mixed with 0.5, 1, and 1.5 w/v% of oleic acid (OA). The operating temperatures were 60, 70, and 80°C. Experimental data showed that the TPEC gave the highest heat flux of about 25 kW/m2 and the highest effectiveness of about 0.3 at a filling ratio of 50%, with the nanofluid containing 1 w/v% of OA. It was further found that the effectiveness of nanofluid and the OA containing nanofluids were superior in effectiveness over water in all experimental conditions came under this study. Moreover, the presence of OA had clearly contributed to raise the effectiveness of the nanofluid. PMID:21711856

  6. Theoretical Design of a Thermosyphon for Efficient Process Heat Removal from Next Generation Nuclear Plant (NGNP) for Production of Hydrogen

    SciTech Connect

    Piyush Sabharwall; Fred Gunnerson; Akira Tokuhiro; Vivek Utgiker; Kevan Weaver; Steven Sherman

    2007-10-01

    The work reported here is the preliminary analysis of two-phase Thermosyphon heat transfer performance with various alkali metals. Thermosyphon is a device for transporting heat from one point to another with quite extraordinary properties. Heat transport occurs via evaporation and condensation, and the heat transport fluid is re-circulated by gravitational force. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. For process heat, intermediate heat exchangers (IHX) are required to transfer heat from the NGNP to the hydrogen plant in the most efficient way possible. The production of power at higher efficiency using Brayton Cycle, and hydrogen production requires both heat at higher temperatures (up to 1000oC) and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. The purpose for selecting a compact heat exchanger is to maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. The IHX design requirements are governed by the allowable temperature drop between the outlet of the NGNP (900oC, based on the current capabilities of NGNP), and the temperatures in the hydrogen production plant. Spiral Heat Exchangers (SHE’s) have superior heat transfer characteristics, and are less susceptible to fouling. Further, heat losses to surroundings are minimized because of its compact configuration. SHEs have never been examined for phase-change heat transfer applications. The research presented provides useful information for thermosyphon design and Spiral Heat Exchanger.

  7. Thermosyphon coil arrangement for heat pump outdoor unit

    DOEpatents

    Draper, R.

    1984-05-22

    For a heat pump, the outdoor unit is provided with a coil and a refrigerant flow arrangement there for which is such that in the heating mode of operation of the heat pump they operate in a thermosyphon fashion. The coil has a feed portion and an exit portion leading to a separator drum from which liquid refrigerant is returned through downcomer line for recirculation to the feed portion. The coil is tilted upwardly from entry to exit by the angle alpha to enhance the clearance of the two phases of refrigerant from each other in the heating mode of operation. There is no thermosyphon function in the cooling mode of operation. 9 figs.

  8. Thermosyphon coil arrangement for heat pump outdoor unit

    DOEpatents

    Draper, Robert (Churchill, PA)

    1984-01-01

    For a heat pump, the outdoor unit is provided with a coil and a refrigerant flow arrangement therefor which is such that in the heating mode of operation of the heat pump they operate in a thermosyphon fashion. The coil 32 has a feed portion 30 and an exit portion 34 leading to a separator drum 36 from which liquid refrigerant is returned through downcomer line 42 for recirculation to the feed portion. The coil is tilted upwardly from entry to exit by the angle alpha to enhance the clearance of the two phases of refrigerant from each other in the heating mode of operation. There is no thermosyphon function in the cooling mode of operation.

  9. The measured performance of an air thermosyphon system

    NASA Astrophysics Data System (ADS)

    Marshall, L. S.; Burns, P. J.; Winn, C. B.

    A simulation scheme was developed to evaluate a passive air thermosyphon system consisting of a double glazed collector, ducting, backdraft dampers to prevent reverse circulation of the air, and a rock box in the north wall for thermal storage. A test cell been constructed in order to obtain actual data. Temperature measurements and flow visualization in the air ducts are studied. The thermal performance of the system is evaluated by using measured data as input for the simulation model.

  10. Flow and Heat Transfer Characteristics in a Closed-Type Two-Phase Loop Thermosyphon

    NASA Astrophysics Data System (ADS)

    Imura, Hideaki; Saito, Yuji; Fujimoto, Hiromitsu

    A closed-loop two-phase thermosyphon can transport a large amount of thermal energy with small temperature differences without any external power supply. A fundamental investigation of flow and heat transfer characteristics was performed experimentally and theoretically using water, ethanol and R113 as the working liquids. Heat transfer coefficients in an evaporator and a condenser, and circulation flow rates were measured experimentally. The effects of liquid fill charge, rotation angle, pressure in the loop and heat flux on the heat transfer coefficients were examined. The heat transfer coefficients in the evaporator and the condenser were correlated by the expressions for pool boiling and film condensation respectively. As a result, the heat transfer coefficients in the evaporator were correlated by the Stephan-Abdelsalam equations within a±40% error. Theoretically, the circulation flow rate was predicted by calculating pressure, temperature, quality and void fraction along the loop. And, the comparison between the calculated and experimental results was made.

  11. Analysis of thermosyphoning in a steam generator model

    SciTech Connect

    Martinez, M.J.; Martinez, G.M.

    1991-10-01

    An analysis of thermosyphoning in a stream generator model is presented. The model considers the transient development of buoyancy-driven steam flow in the steam generator tubing, secondary side heat transfer and an inlet plenum mixing model. Numerical solutions are obtained for conditions intended to simulate the natural circulation phenomena in a 3-Loop pressurized water reactor in a loss-of-coolant accident scenario. The relation between the circulation rate and the heating rate is determined. The sensitivity of the model to various key parameters is examined. 16 refs.

  12. The liquid helium thermosyphon for the GEM detector magnet

    SciTech Connect

    Warren, R.P.

    1993-05-04

    The GEM detector magnet, a horizontal solenoid 19.5 m in diameter and wound with a niobium-titanium cable in conduit, will be located with it`s axis 19.5 m below grade. The conductor is wound on the inside of an aluminum bobbin which is cooled by liquid helium which flows by natural convection in a thermosyphon loop from a large storage dewar located at the ground surface. The function of the thermosyphon system is to absorb the environmental heat load as well as any internally generated heat. In the first category is included that heat which is transfered to the magnet by way of the mechanical supports, the insulation and the current leads. The internally generated heat includes the resistive heating within the normally conducting conductor splices and the inductive heating of the bobbin during current transients. Though similar systems have been employed elsewhere, there are some unique aspects to the present design. By taking advantage of the large vertical head available, the parallel heat exchanger passes within the magnet remain sub-cooled, thus insuring single phase coolant within the magnet. It is believed that this will be the first instance of such a large vertical head being used to this advantage in a helium system.

  13. A parametric study of heat transfer within a planar thermosyphon

    SciTech Connect

    Clarksean, R.; Phillips, G.

    1993-08-01

    The results of a parametric study for a planar thermosyphon are presented. The thermosyphon consists of a ``U-shaped`` geometry, with the center portion of the ``U`` being a solid. The outer legs of the ``U`` are the flow channels. One of the outer surfaces of a channel was held at a constant temperature. The remaining outer surfaces were considered adiabatic. The configuration described is characteristic of passive systems for radioactive waste storage and reactor safety systems. Parameters which were varied included the channel geometry, the thermal conductivity of the solid, and the Ra number. The average Nu number for the constant temperature surface decreased as the inlet channel width decreased, and as the thermal conductivity of the solid increased. A modified Ra number, defined as the Ra number divided by the length to gap ratio for the outer channel, is used in the paper. At low values of the modified Ra number, there is over an order of magnitude decrease in the average Vu number for a change in the inlet channel width from 1.0 to 0.25. But as the value of the modified Ra number increases for any inlet channel width, the average Vu number results approached those of vertical parallel plates, independent of the inlet channel width and the thermal conductivity of the solid. The vertical parallel plate data is approached because the boundary layer flow near the heated plate is unaffected by the surface of the intervening solid.

  14. Experimental investigation of natural convection in U-shaped thermosyphon

    SciTech Connect

    Al-Khawajah, M.F.; Mohamad, A.A.

    1995-12-31

    An experimental apparatus is designed to investigate the thermal performance of U-shaped thermosyphon. The test rig mainly consists of a deep cavity (77 cm in height) with opening at the top. An air baffle is inserted at the middle of the cavity. One of the vertical walls of the cavity is maintained at constant heat flux, while the other vertical wall is exposed to the ambient condition. Connecting walls are insulated thermally. The objective of the work is to gain a fundamental understanding of the natural flow and heat transfer from the mentioned system. Temperature distribution along the heated plate and thermal boundary layer are measured at different locations along the thermosyphon for certain range of parameters (Rayleigh number, geometrical parameters). Experimentally obtained data are compared with data of free convection along isolated flat plate. It is found that the rate of heat transfer at the beginning of the heated plate is higher than the heat transfer from flat plate, but at certain height the rate of heat transfer becomes lower than the rate of heat transfer from isolated flat plate.

  15. Experimental analysis of natural convection within a thermosyphon

    SciTech Connect

    Clarksean, R.

    1993-09-01

    The heat transfer characteristics of a thermosyphon designed to passively cool cylindrical heat sources are experimentally studied. The analysis is based on recognizing the physics of the flow within different regions of the thermosyphon to develop empirical heat transfer correlations. The basic system consists of three concentric cylinders, with an outer channel between the outer two cylinders, and an inner channel between the inner two cylinders. Tests were conducted. with two different process material container diameters, representing the inner cylinder, and several different power levels. The experimentally determined local and average Nu numbers for the inner channel are in good agreement with previous work for natural convection between vertical parallel plates, one uniformly heated and the other thermally insulated. The implication is that the heat transfer off of each surface is independent of the adjacent surface for sufficiently high Ra numbers. The heat transfer is independent because of limited interaction between the boundary layers at sufficiently high Ra numbers. As a result of the limited interaction, the maximum temperature within the system remained constant, or decreased slightly when the radii of the inner cylinders increased for the same amount of heat removal.

  16. Thermosyphon Method for Cooling the Rotor Blades of High-Temperature Steam Turbines

    NASA Astrophysics Data System (ADS)

    Bogomolov, Alexander R.; Temnikova, Elena Yu.

    2016-02-01

    The design scheme of closed two-phase thermosyphon were suggested that can provide standard thermal operation of blades of high-temperature steam turbine. The method for thermosyphon calculation is developed. The example of thermal calculation was implemented, it showed that to cool the steam turbine blades at their heating by high-temperature steam, the heat can be removed in the rear part of the blades by air with the temperature of about 440°C.

  17. Theoretical Design of Thermosyphon for Process Heat Transfer from NGNP to Hydrogen Plant

    SciTech Connect

    Piyush Sabharwall; Mike Patterson; Fred Gunnerson

    2008-09-01

    The Next Generation Nuclear Plant (NGNP) will most likely produce electricity and process heat, with both being considered for hydrogen production. To capture nuclear process heat, and transport it to a distant industrial facility requires a high temperature system of heat exchangers, pumps and/or compressors. The heat transfer system is particularly challenging not only due to the elevated temperatures (up to ~ 1300K) and industrial scale power transport (=50 MW), but also due to a potentially large separation distance between the nuclear and industrial plants (100+m) dictated by safety and licensing mandates. The work reported here is the preliminary analysis of two-phase thermosyphon heat transfer performance with alkali metals. A thermosyphon is a device for transporting heat from one point to another with quite extraordinary properties. In contrast to single-phased forced convective heat transfer via ‘pumping a fluid’, a thermosyphon (also called a wickless heat pipe) transfers heat through the vaporization / condensing process. The condensate is further returned to the hot source by gravity, i.e. without any requirement of pumps or compressors. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. Two-phase heat transfer by a thermosyphon has the advantage of high enthalpy transport that includes the sensible heat of the liquid, the latent heat of vaporization, and vapor superheat. In contrast, single-phase forced convection transports only the sensible heat of the fluid. Additionally, vapor-phase velocities within a thermosyphon are much greater than single-phase liquid velocities within a forced convective loop. Thermosyphon performance can be limited by the sonic limit (choking) or vapor flow and/or by condensate entrainment. Proper thermosyphon requires analysis of both.

  18. Mathematical Modeling of Hydrodynamic and Heat Transfer in a Two-Phase Thermosyphon

    NASA Astrophysics Data System (ADS)

    Nee, Alexander; Nurpeiis, Atlant

    2016-02-01

    This paper presents the solution results of conjugate forced convection boundary value problem in a typical rectangular cross-section thermosyphon. The influence of convective heat exchange at the external top horizontal boundary on the heat transfer intensity in such energy removing device is shown. It is found that temperature distributions in thermosyphon steam channel to the Y direction obtain monotonous character with increasing heat exchange coefficient to the environment.

  19. Cooling of electronics by heat pipes and thermosyphons -- A review of methods and possibilities

    SciTech Connect

    Palm, B.; Tengblad, N.

    1996-12-31

    In this paper, passive techniques for cooling of electronic components by boiling and condensation are reviewed. Heat pipes, thermosyphon pipes, as well as simple and advanced thermosyphon loops are treated. Performance limitations for each type are discussed, as well as benefits and disadvantages with immersion boiling compared to indirect cooling. Numerous examples of designs from the literature are shown and their performance characteristics are cited.

  20. Thermal performance analysis of nanofluids in a thermosyphon heat pipe using CFD modeling

    NASA Astrophysics Data System (ADS)

    Asmaie, L.; Haghshenasfard, M.; Mehrabani-Zeinabad, A.; Nasr Esfahany, M.

    2013-05-01

    A computational fluid dynamics model for simulation of a thermosyphon with two-phase flow including phase change heat transfer was developed. De-ionized water and CuO/Water nanofluid were used as working fluids in the thermosyphon. Results show that, maximum heat flux of the nanofluid is about 46 % higher than that of water. Also by increasing the nanofluid concentration, the wall temperature decreases, and the concentration of 1 wt% is the optimum concentration.

  1. Fuzzy model representation of thermosyphon solar water heating system

    SciTech Connect

    Kishor, Nand; Narain, Anirudha; Prakash Ranjan, Vibhaw; Das, Mihir Kr.

    2010-06-15

    The aim of this paper is to focus on improvement in prediction accuracy of model for thermosyphon solar water heating (SWH) system. The work employs grey-box modeling approach based on fuzzy system to predict the outlet water temperature of the said system. The prediction performance results are compared with neural network technique, which has been suggested by various researchers in the last one decade. The outlet water temperature prediction by fuzzy modeling technique is analyzed by using 3 models, one with three inputs (inlet water temperature, ambient temperature, solar irradiance), next with two inputs (inlet water temperature, solar irradiance) and last one with single input (solar irradiance/inlet water temperature). An improved prediction performance is observed with three inputs fuzzy model. (author)

  2. Observations on an evaporative, elbow thermosyphon

    SciTech Connect

    Lock, G.S.H.; Fu, J. )

    1993-05-01

    The performance of the evaporative elbow system was found to be superior to that of the nonevaporative system, but comparable to the performance of the linear system. The parametric role of the evaporator wall temperature, the condenser wall temperature, and the vapor saturation temperature was demonstrated, each revealing a similar monotonic effect. With the evaporator upright, the data were found to be similar to, but displaced from, the upright condenser data. The upright evaporator gave the better performance, but not overwhelmingly so. The limit of performance with the condenser upright was found to be dictated by evaporator dryout. In the upright evaporator configuration, the limit may be attributed to flooding in the poorly draining condenser; this limit was indistinguishable from geyser behavior at low vapor pressures. 16 refs., 3 figs.

  3. Operating manual for hybrid thermosyphons at the Gakona Power Plant, Alaska. Special report

    SciTech Connect

    Haynes, F.D.; Crory, F.C.; Knuth, K.V.; Quinn, W.F.

    1994-03-01

    A power plant building was constructed in 1990 at an over-the-horizon radar site in Gakona, Alaska. Since it was built on permafrost, thermal protection between the building and the underlying permafrost was included in the design, which included rigid board insulation and hybrid thermosyphons placed in the gravel fill under the building. Soil temperature is monitored with eight thermistor strings placed under and at the building perimeter. This manual describes the steps that must be taken to ensure foundation stability, including directions on when to use the thermosyphons in the active, mechanical refrigeration mode. A data acquisition system using a computer-controlled datalogger is described.

  4. Experimental investigation of natural convection heat transfer in an open thermosyphon

    NASA Astrophysics Data System (ADS)

    Imura, H.; Kozai, H.

    1986-04-01

    An experimental investigation of natural convection heat transfer has been performed under the condition of uniform heat flux in an open thermosyphon. Water, ethyl alcohol and ethylene glycol were used as working liquids. The length-to-radius ratio, expressing the thermosyphon tube geometry, was changed in the range from 14.3 to 92.8 by using seven tubes with different dimensions. Expressions correlating the experimental data on heat transfer coefficients were derived for both laminar and turbulent flow regimes. Axial temperature distributions of the heated wall and working liquid were measured and discussed in relation to the flow regimes.

  5. Investigation of the overall transient performance of the industrial two-phase closed loop thermosyphon

    NASA Astrophysics Data System (ADS)

    Vincent, Charles C. J.; Kok, Jim B. W.

    1992-06-01

    The two-phase closed loop thermosyphon is investigated with emphasis on the overall performance in transient operation. The control volume approach is the base of a global analysis describing the motion of vapor and liquid phases of the thermosyphon system in one-dimensional equations. Interfacial shear forces are neglected as only co-current flows are present. Heat transfer coefficients are based on empirical correlations. It is found that the density ratio vapor-liquid, dimensionless friction coefficient, and water column length determine respectively the overall dynamic behavior characteristics such as response time, damping, and oscillation frequency.

  6. Heat transfer performance of an inclined two-phase closed thermosyphon

    NASA Astrophysics Data System (ADS)

    Negishi, K.; Sawada, T.

    1983-08-01

    An experimental study on the heat transfer performance of an inclined two-phase closed thermosyphon is described. Water and ethanol have been used as the working fluids. The amount of working fluid and the inclination angle have been used as the experimental parameters. A visualization of the movement of liquid with boiling, the scattering of liquid drops and the condensation of vapor has made clear the heat transfer mechanism in the thermosyphon. In addition, the overall heat transfer coefficients and the thermal diode characteristics have been obtained.

  7. Engineering design elements of a two-phase thermosyphon to transfer nuclear thermal energy to a hydrogen plant

    NASA Astrophysics Data System (ADS)

    Sabharwall, Piyush

    Two hydrogen production processes, both powered by Next Generation Nuclear Plant (NGNP), are currently under investigation at the Idaho National Laboratory. The first is high-temperature steam electrolysis utilizing both heat and electricity and the second is thermo-chemical production through the sulfur-iodine process primarily utilizing heat. Both processes require high temperature (>850°C) for enhanced efficiency; temperatures indicative of NGNP. Safety and licensing mandates prudently dictate that the NGNP and the hydrogen production facility be physically isolated, perhaps requiring separation of over 100m. There are several options to transferring multi-megawatt thermal power over such a distance. One option is simply to produce only electricity, transfer by wire to the hydrogen plant, and then reconvert the electric energy to heat via Joule or induction heating. Electrical transport, however, suffers energy losses of 60-70% due to the thermal to electric conversion inherent in the Brayton cycle. A second option is thermal energy transport via a single-phase forced convection loop where a fluid is mechanically pumped between heat exchangers at the nuclear and hydrogen plants. High temperatures, however, present unique materials and pumping challenges. Single phase, low pressure helium is an attractive option for NGNP, but is not suitable for a single purpose facility dictated to hydrogen production because low pressure helium requires higher pumping power and makes the process very inefficient. A third option is two-phase heat transfer utilizing a high temperature thermosyphon. Heat transport occurs via evaporation and condensation, and the heat transport fluid is re-circulated by gravitational force. Thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. For process heat, intermediate heat exchangers (IHX) are desired to transfer heat from the NGNP to the hydrogen plant in the most efficient way possible. The production of power at higher efficiency using Brayton Cycle, and hydrogen production requires both heat at higher temperatures (up to 1000°C) and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. The purpose in selecting a compact heat exchanger is to maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. The IHX design requirements are governed by the allowable temperature drop between the outlet of the NGNP (900°C, based on the current capabilities of NGNP), and the temperatures in the hydrogen production plant. Spiral Heat Exchangers (SHEs) have superior heat transfer characteristics, and are less susceptible to fouling. Further, heat losses to surroundings are minimized because of its compact configuration. SHEs have never been examined for phase-change heat transfer applications. The research presented provides useful information for thermosyphon design and Spiral Heat Exchanger. This research provides useful insight in making decisions regarding the thermosyphon heat transfer system between the nuclear reactor and chemical plant. Development of very high-temperature reactor technologies for the production of electricity, hydrogen and other energy products is a high priority for a successful national energy future.

  8. Development, testing and certification of the sigma research, maxi-therm-S-101 thermosyphon heat exchanger

    NASA Technical Reports Server (NTRS)

    Hankins, J. D.

    1979-01-01

    A thermosyphon liquid-to-air heat exchanger developed for use in heating systems in residential single family dwellings and small commercial applications is described. The cabinet design, rationale for the horizontal positioning of the exchanger, and design of the shut-off valve are discussed. The performance of the heating module is given in tabular form.

  9. Passively operated spool valve for drain-down freeze protection of thermosyphon water heaters. Final technical report

    SciTech Connect

    1982-04-30

    The work done to extend the existing drain-down valve technology to provide passive drain-down freeze protection for thermosyphon-based solar water heaters is described. The basic design of the existing valve model is that of a spool valve, employing a cylindrical spool which moves axially in a mating cartridge to open and close o-rings at the two operating extremes (drain and operate) to perform the valving function. Three passive actuators to drive the basic valving mechanism were designed, fabricated, and tested. Two piping configurations used to integrate the spool valve with the thermosyphon system are described, as are the passive actuators. The three actuator designs are: photovoltaic driven, refrigerant-based bellows, and heat motor cable-drive designs. Costs are compared for the alternative actuator designs, and operating characteristics were examined for the thermosyphon system, including field tests. The market for the valve for thermosyphon systems is then assessed. (LEW)

  10. Thermal Interface Evaluation of Heat Transfer from a Pumped Loop to Titanium-Water Thermosyphons

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Sanzi, James L.; Gibson, Marc A.; Sechkar, Edward A.

    2009-01-01

    Titanium-water thermosyphons are being considered for use in the heat rejection system for lunar outpost fission surface power. Key to their use is heat transfer between a closed loop heat source and the heat pipe evaporators. This work describes laboratory testing of several interfaces that were evaluated for their thermal performance characteristics, in the temperature range of 350 to 400 K, utilizing a water closed loop heat source and multiple thermosyphon evaporator geometries. A gas gap calorimeter was used to measure heat flow at steady state. Thermocouples in the closed loop heat source and on the evaporator were used to measure thermal conductance. The interfaces were in two generic categories, those immersed in the water closed loop heat source and those clamped to the water closed loop heat source with differing thermal conductive agents. In general, immersed evaporators showed better overall performance than their clamped counterparts. Selected clamped evaporator geometries offered promise.

  11. Development of a flexible thermosyphon for cooling a concentrated heat source

    SciTech Connect

    McKee, R.S.; Hobbs, F.D.

    1995-05-01

    A flexible tubular thermosyphon was developed for the purpose of cooling a concentrated heat source. Designed to fold 180{degrees} for storage and unfold for operation, the thermosyphon is made of copper and uses water as the working fluid. Its integral flex-joint has several advantages over conventional flexible joints. A unique boiling enhancement improved the liquid-to-vapor phase change while minimizing the conduction-temperature drop from the tube wall to the fluid, and was found to perform better than a screen wick in the evaporator. A study of the power limits and of other working fluids was conducted with the HTPIPE computer code (Los Alamos). Power limits were calculated to be far in excess of what was needed, but experiments revealed that the limits were significantly lower. Water was predicted to be the best working fluid at the operational temperature range but this was not experimentally verified.

  12. Performance evaluation of a refrigerant-charged thermosyphon solar DHW system

    SciTech Connect

    Farrington, R.; DeAngelis, M.; Morrison, L.; Dougherty, D.

    1981-04-01

    Refrigerant-charged passive solar domestic hot water (SDHW) systems, which have recently become commercially available, are generating great interest in the solar community. These systems, which can be installed even in freezing climates, may achieve the high performance and reliability of direct thermosyphon systems. The Solar Energy Research Institute (SERI) is testing and analyzing a promixing prototype refrigerant-charged thermosyphon system; SERI also plans to evaluate a commercially available system. The prototype was installed in a single-family residence using a stabilized R-11 as the heat transfer fluid. A system analysis was performed based on measured data. The analysis method and preliminary results, which indicate that there is reason to be optimistic about this type of system are discussed.

  13. Computer cooling using a two phase minichannel thermosyphon loop heated from horizontal and vertical sides and cooled from vertical side

    NASA Astrophysics Data System (ADS)

    Bieli?ski, Henryk; Mikielewicz, Jaros?aw

    2010-10-01

    In the present paper it is proposed to consider the computer cooling capacity using the thermosyphon loop. A closed thermosyphon loop consists of combined two heaters and a cooler connected to each other by tubes. The first heater may be a CPU processor located on the motherboard of the personal computer. The second heater may be a chip of a graphic card placed perpendicular to the motherboard of personal computer. The cooler can be placed above the heaters on the computer chassis. The thermosyphon cooling system on the use of computer can be modeled using the rectangular thermosyphon loop with minichannels heated at the bottom horizontal side and the bottom vertical side and cooled at the upper vertical side. The riser and a downcomer connect these parts. A one-dimensional model of two-phase flow and heat transfer in a closed thermosyphon loop is based on mass, momentum, and energy balances in the evaporators, rising tube, condenser and the falling tube. The separate two-phase flow model is used in calculations. A numerical investigation for the analysis of the mass flux rate and heat transfer coefficient in the steady state has been accomplished.

  14. RELAP5 Model of a Two-phase ThermoSyphon Experimental Facility for Fuels and Materials Irradiation

    SciTech Connect

    Carbajo, Juan J; McDuffee, Joel Lee

    2013-01-01

    The High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) does not have a separate materials-irradiation flow loop and requires most materials and all fuel experiments to be placed inside a containment. This is necessary to ensure that internal contaminants such as fission products cannot be released into the primary coolant. As part of the safety basis justification, HFIR also requires that all experiments be able to withstand various accident conditions (e.g., loss of coolant) without generating vapor bubbles on the surface of the experiment in the primary coolant. As with any parallel flow system, HFIR is vulnerable to flow excursion events when vapor is generated in one of those flow paths. The effects of these requirements are to artificially increase experiment temperatures by introducing a barrier between the experimental materials and the HFIR coolant and to reduce experiment heat loads to ensure boiling doesn t occur. A new experimental facility for materials irradiation and testing in the HFIR is currently being developed to overcome these limitations. The new facility is unique in that it will have its own internal cooling flow totally independent of the reactor primary coolant and boiling is permitted. The reactor primary coolant will cool the outside of this facility without contacting the materials inside. The ThermoSyphon Test Loop (TSTL), a full scale prototype of the proposed irradiation facility to be tested outside the reactor, is being designed and fabricated (Ref. 1). The TSTL is a closed system working as a two-phase thermosyphon. A schematic is shown in Fig. 1. The bottom central part is the boiler/evaporator and contains three electric heaters. The vapor generated by the heaters will rise and be condensed in the upper condenser, the condensate will drain down the side walls and be circulated via a downcomer back into the bottom of the boiler. An external flow system provides coolant that simulates the HFIR primary coolant. The two-phase flow code RELAP5-3D (Ref. 2) is the main tool employed in this design. The model has multiple challenges: boiling, condensation and natural convection flows need to be modeled accurately.

  15. A Thermosyphon Titanium-Water Heat Pipe Design for a Lunar Surface Power System

    SciTech Connect

    Thayer, John; Semenov, Sergey

    2009-03-16

    A long titanium-water thermosyphon heat pipe was designed and tested in support of NASA's lunar surface power system. With a {delta}T of 11.6 C, a prototype has been shown to meet the temperature drop specification of 15 C at 400 W and 400 K. The heat pipe is designed to be embedded in a composite radiator panel to spread waste heat delivered by a circulating pumped loop. The major challenge was managing the fluid inventory to balance the conflicting requirements of power capacity and freeze-thaw tolerance. A unique hybrid wick was designed to achieve the required thermal performance and yet store all the working fluid during idle periods in a freeze-thaw tolerant fashion. A non-condensable gas charge was used to boost power capacity at lower operating temperatures. Eighteen prototypes will be built and tested.

  16. Experimental study on the performance characteristics of an enhanced two-phase loop thermosyphon

    NASA Astrophysics Data System (ADS)

    Ziapour, Behrooz M.; Baygan, Majid; Mohammadnia, Ali

    2015-10-01

    A two-phase loop thermosyphon (TPLT) is an apparatus for heat transmission from the hot section of system (evaporator) to the cold part (condenser), with relatively small temperature differences. The setup used in this study consists of a TPLT, including evaporator, riser, an advanced condenser and downcomer. The condenser inlet has a nozzle. The steam rises from evaporator, flows through the nozzle and sprays on a vertical copper surface inside the condenser. To cool the copper sheet, then a cooler system was installed rear of it. The experimental tests were performed for presence of the nozzle and without it. The results showed that the TPLT efficiency increases for the modified condenser using nozzle. Also, the overall heat transfer coefficient of TPLT is enhanced by the nozzle. In the case of the nozzle with distance of 13 mm from copper sheet, and T e, sat > 55 °C, the value of suddenly increased.

  17. Non-Isothermal Experimental Study of the Constrained Vapor Bubble Thermosyphon

    NASA Technical Reports Server (NTRS)

    Karthikeyan, Muthu; Huang, Jianming; Plawsky, Joel; Wayner, Peter, Jr.

    1996-01-01

    Experimental and theoretical techniques to study non-isothermal transport processes in the constrained vapor bubble thermosyphon (CVBT) were developed using a pentane/quartz system. The transport processes can be evaluated by measuring the liquid film profile, which gives the pressure field, and the temperature field. The axial variation in the capillary pressure was measured using an image-analyzing interferometer that is based on computer-enhanced video microscopy of the naturally occurring interference fringes. Thermoelectric coolers were used to control the temperature level in the condensation region and, therefore, the length of the approximately 'adiabatic' surface region which is a function of the temperature difference between the CVBT surface and the surroundings. High values for the axial thermal conductance in the 'adiabatic' surface region were demonstrated under certain conditions.

  18. Thermal characteristics of two phase thermosyphon cooling module for multi-chip device

    SciTech Connect

    Choi, S.B.; Nam, S.S.; Kim, J.H.; Kwak, H.Y.

    1996-12-31

    A thermosyphonic cooling module (TSCM) has been designed, fabricated and tested to cool the multi-chip plugged into a planar packaging system. The cooling module consists of a cold plate and an integrated condenser. With an allowable temperature rise of 56 C on the surface of the heater, the cooling module TSCM can handle a heat flux about 2.7 W/cm{sup 2}. The transient characteristics of the cooling module have proved to be excellent; that is, when a heat load is applied to the system, steady state can be achieved within 10--15 minutes. It has been found that the length of the vapor channel between the cold plate and the condenser and ambient as well as the condenser temperatures affect the system performance.

  19. Heat transfer characteristics of two-phase thermosyphon heat pipe. I - Boiling heat transfer correlation in heating section

    NASA Astrophysics Data System (ADS)

    Kaminaga, Fumito; Okamoto, Yoshizo

    1992-08-01

    A correlation for the boiling heat transfer coefficient in the heating section of a two-phase thermosyphon heat pipe is developed in comparison with experimental data. The experiments are conducted for a vertically oriented thermosyphon pipe using three kinds of working fluid, water, Feron R 113, and ethanol, at a wide pressure range of 0.1 to 20 bar and a fill charge rate of 0.3 to 0.9. The correlation is obtained by modification of Kutateladze's nucleate boiling correlation in terms of an additional two parameters, the density ratio of liquid and vapor and the surface roughness. The correlation is shown to be in good agreement with the experimental data at a system pressure above 1 bar. The experiments also indicate that the adiabatic wall temperature is less than the saturation temperature corresponding to the system pressure in the pipe.

  20. Interfacial Force Field Characterization in a Constrained Vapor Bubble Thermosyphon

    NASA Technical Reports Server (NTRS)

    DasGupta, Sunando; Plawsky, Joel L.; Wayner, Peter C., Jr.

    1995-01-01

    Isothermal profiles of the extended meniscus in a quartz cuvette were measured in the earth's gravitational field using an image-analyzing interferometer that is based on computer-enhanced video microscopy of the naturally occurring interference fringes. These profiles are a function of the stress field. Experimentally, the augmented Young-Laplace equation is an excellent model for the force field at the solid-liquid-vapor interfaces for heptane and pentane menisci on quartz and tetradecane on SFL6. The effects of refractive indices of the solid and liquid on the measurement techniques were demonstrated. Experimentally obtained values of the disjoining pressure and dispersion constants were compared to those predicted from the Dzyaloshinskii - Lifshitz - Pilaevskii theory for an ideal surface and reasonable agreements were obtained. A parameter introduced gives a quantitative measurement of the closeness of the system to equilibrium. The nonequilibrium behavior of this parameter is also presented

  1. A Study of the Constrained Vapor Bubble Thermosyphon

    NASA Technical Reports Server (NTRS)

    Wayner, Peter C., Jr.; Plawsky, J. L.

    2000-01-01

    The objective of this effort is to better understand the physics of evaporation, condensation, and fluid flow as they affect the heat transfer processes in a constrained vapor bubble heat exchanger (CVBHX). This CVBHX consists of a small enclosed container with a square cross section (inside dimensions. 3 x 3 x 40 mm) partially filled with a liquid. The major portion of the liquid is in the corners, which act as arteries. When a temperature difference is applied to the ends of the CVBHX, evaporation occurs at the hot end and condensation at the cold end resulting in a very effective heat transfer device with great potential in space applications. Liquid is returned by capillary flow in the corners. A complete description of the system and the results obtained to date are given in the papers listed.

  2. Determination of the dispersion constant in a constrained vapor bubble thermosyphon

    NASA Technical Reports Server (NTRS)

    Dasgupta, Sunando; Plawsky, Joel L.; Wayner, Peter C., Jr.

    1995-01-01

    The isothermal profiles of the extended meniscus in a quartz cuvette were measured in a gravitational field using an image analyzing interferometer which is based on computer enhanced video microscopy of the naturally occurring interference fringes. The experimental results for heptane and pentane menisci were analyzed using the extended Young Laplace Equation. These isothermal results characterized the interfacial force field in-siru at the start of the heat transfer experiments by quantifying the dispersion constant, which is a function of the liquid-solid system and cleaning procedures. The experimentally obtained values of the disjoining pressure and the dispersion constants were compared to that predicted from the DLP theory and good agreements were obtained. The measurements are critical to the subsequent non-isothermal experiments because one of the major variables in the heat sink capability of the Constrained Vapor Bubble Thermosyphon, CVBT, is the dispersion constant. In all previous studies of micro heat pipes the value of the dispersion constant has been 'estimated'. One of the major advantages of the current glass cell is the ability to view the extended meniscus at all times. Experimentally, we find that the extended Young-Laplace Equation is an excellent model for the force field at the solid-liquid-vapor interfaces.

  3. Experimental measurement and mathematical calculation evaporator temperatures of closed loop thermosyphon

    NASA Astrophysics Data System (ADS)

    Nemec, Patrik; Malcho, Milan; Janda?ka, Jozef

    2013-10-01

    The closed loop thermoshypon is device operate with working fluid phase change principle. It is a simple and reliable device providing heat transfer. This device utilizes the thermodynamic pressure difference and gravitation to circulate working fluid and has extremely high effective thermal conductivity. Usually is used to cooling of electronic components. The paper describes a design and construction of this device. As a working fluid was used fluorinert FC-72. Next the paper deal with dependences measurement of evaporator temperatures on waste heat of the electronic component and their verification by means of a mathematic calculation based on physical phenomena of boiling, condensation and heat transfer.

  4. Analytical and experimental study of steady-state convection in a double-loop thermosyphon

    NASA Astrophysics Data System (ADS)

    Sen, Mihir; Pruzan, D. A.; Torrance, K. E.

    1988-04-01

    Steady-state natural convection in a toroidal loop with a heated diametrical branch and cooled side branches is studied. The loop is rotated to vary the tilt angle of the diametral branch. A one-dimensional analysis provides the fluid velocities and temperature distributions in the loop. The effects of axial conduction are examined. With increasing tilt from the vertical, the fluid in the lower side branch slows down and reverses. The flow through the central branch increases and the main return path is through the upper side branch. For small tilt angles around the horizontal, multiple steady states exist. Comparison experiments on a water-filled glass loop are in qualitative agreement with the analysis and multiple steady states are observed.

  5. Controlling natural convection in a closed thermosyphon using neural networks

    NASA Astrophysics Data System (ADS)

    Cammarata, L.; Fichera, A.; Pagano, A.

    . The aim of this paper is to present a neural network-based approach to identification and control of a rectangular natural circulation loop. The first part of the paper defines a NARMAX model for the prediction of the experimental oscillating behavior characterizing the fluid temperature. The model has been generalized and implemented by means of a Multilayer Perceptron Neural Network that has been trained to simulate the system experimental dynamics. In the second part of the paper, the NARMAX model has been used to simulate the plant during the training of another neural network aiming to suppress the undesired oscillating behavior of the system. In order to define the neural controller, a cascade of several couples of neural networks representing both the system and the controller has been used, the number of couples coinciding with the number of steps in which the control action is exerted.

  6. Black Liquid Solar Collector Demonstrator.

    ERIC Educational Resources Information Center

    Weichman, F. L.; Austen, D. J.

    1979-01-01

    Describes the details of constructing, and use of, a solar collector. Uses a black liquid to absorb the energy, the thermosyphon effect to drive the liquid through the collector, and a floodlamp as a surrogate sun. (GA)

  7. Experimental investigation on the effect of nanofluid on the thermal performance of symmetric sintered U shaped heat pipe

    NASA Astrophysics Data System (ADS)

    Nazarimanesh, Meysam; Yousefi, Tooraj; Ashjaee, Mehdi

    2015-08-01

    In this study, the impact of Entrance Power and Silver nanofluid concentration (with base fluid ethanol and DI-water) on heat pipe thermal performance are considered. In order to reach the aim a U-shaped sintered heat pipe is utilized which causes occupied space to decline. The length of the heat pipe is 135 mm in each branch. On account of recognition the effect of working fluid on heat pipe thermal performance, thermal resistance and overall heat transfer coefficient in base working fluid and nano-colloidal silver are measured in the shape of thermosyphon. The working fluid is with volume percentages of 70 ethanol and 30 distilled water. The average size pertaining to the nanoparticle applied is 40 nm. In addition, the influences of nanofluid concentrations are measured by comparing three concentrations 0.001, 0.005, 0.1 vol%. The range of entrance power is from 10 to 40 W and the temperature of coolant has been changed from 20 to 40 °C. The results of the experiment indicate that by increasing entrance power, the temperatures of the condenser, evaporator and working temperature experience a rise. Furthermore, this causes a decrease of thermal resistance and an increase of overall heat transfer coefficient. A comparison of three concentrations reveals that in concentration of 50 ppm, thermal resistance compared to the base fluid has decreased to 42.26 % and overall heat transfer coefficient has gone up to 1883 (W/m2·°K) . Also, due to unexpected changes in concentration of 1000 ppm, the existence of an optimized concentration for the silver nanofluid in this heat pipe with this geometry has been clear.

  8. Determination of the dispersion constant in a constrained vapor bubble thermosyphon

    NASA Technical Reports Server (NTRS)

    Dasgupta, SUNANDO.; Plawsky, Joel L.; Wayner, Peter C., Jr.

    1993-01-01

    The isothermal profiles of the extended meniscus in a quartz cuvette were measured in a gravitational field using an image analyzing interferometer which is based on computer enhanced video microscopy of the naturally occurring interference fringes. The experimental results for heptane and pentane menisci were analyzed using the extended Young-Laplace equation. These isothermal results characterized the interfacial force field in-situ at the start of the heat transfer experiments by quantifying the dispersion constant, which is a function of the liquid-solid system and cleaning procedures. The experimentally obtained values of the disjoining pressure and the dispersion constants were compared to that predicted from the DLP theory and good agreements were obtained. The measurements are critical to the subsequent non-isothermal experiments because one of the major variables in the heat sink capability of the CVBT is the dispersion constant. In all previous studies of micro heat pipes the value of the dispersion constant has been 'guesstimated'. One of the major advantages of the current glass cell is the ability to view the extended meniscus at all times. Experimentally. we find that the extended Young-Laplace equation is an excellent model for the force field at the solid-liquid-vapor interfaces.

  9. Interfacial force field characterization of a constrained vapor bubble thermosyphon using IAI

    NASA Technical Reports Server (NTRS)

    Dasgupta, Sunando; Plawsky, Joel L.; Wayner, Peter C., Jr.

    1994-01-01

    The isothermal profiles of the extended meniscus in a quartz cuvette were measured in a gravitational field using IAI (image analyzing interferometer) which is based on computer enhanced video microscopy of the naturally occurring interference fringes. The experimental results for heptane and pentane menisci were analyzed using the extended Young-Laplace Equation. These isothermal results characterized the interfacial force field in-situ at the start of the heat transfer experiments by quantifying the dispersion constant for the specific liquid-solid system. The experimentally obtained values of the disjoining pressures and the dispersion constants are compared to the subsequent non-isothermal experiments because one of the major variables in the heat sink capability of the CVBT is the dispersion constant. In all previous studies of micro heat pipes the value of the dispersion constant has been 'guesstimated'. The major advantages of the current glass cell is the ability to view the extended meniscus at all times. Experimentally, we find that the extended Young-Laplace Equation is an excellent model for for the force field at the solid-liquid vapor interfaces.

  10. Predicting Flow Reversals in a Computational Fluid Dynamics Simulated Thermosyphon Using Data Assimilation.

    PubMed

    Reagan, Andrew J; Dubief, Yves; Dodds, Peter Sheridan; Danforth, Christopher M

    2016-01-01

    A thermal convection loop is a annular chamber filled with water, heated on the bottom half and cooled on the top half. With sufficiently large forcing of heat, the direction of fluid flow in the loop oscillates chaotically, dynamics analogous to the Earth's weather. As is the case for state-of-the-art weather models, we only observe the statistics over a small region of state space, making prediction difficult. To overcome this challenge, data assimilation (DA) methods, and specifically ensemble methods, use the computational model itself to estimate the uncertainty of the model to optimally combine these observations into an initial condition for predicting the future state. Here, we build and verify four distinct DA methods, and then, we perform a twin model experiment with the computational fluid dynamics simulation of the loop using the Ensemble Transform Kalman Filter (ETKF) to assimilate observations and predict flow reversals. We show that using adaptively shaped localized covariance outperforms static localized covariance with the ETKF, and allows for the use of less observations in predicting flow reversals. We also show that a Dynamic Mode Decomposition (DMD) of the temperature and velocity fields recovers the low dimensional system underlying reversals, finding specific modes which together are predictive of reversal direction. PMID:26849061

  11. Predicting Flow Reversals in a Computational Fluid Dynamics Simulated Thermosyphon Using Data Assimilation

    PubMed Central

    Reagan, Andrew J.; Dubief, Yves; Dodds, Peter Sheridan; Danforth, Christopher M.

    2016-01-01

    A thermal convection loop is a annular chamber filled with water, heated on the bottom half and cooled on the top half. With sufficiently large forcing of heat, the direction of fluid flow in the loop oscillates chaotically, dynamics analogous to the Earth’s weather. As is the case for state-of-the-art weather models, we only observe the statistics over a small region of state space, making prediction difficult. To overcome this challenge, data assimilation (DA) methods, and specifically ensemble methods, use the computational model itself to estimate the uncertainty of the model to optimally combine these observations into an initial condition for predicting the future state. Here, we build and verify four distinct DA methods, and then, we perform a twin model experiment with the computational fluid dynamics simulation of the loop using the Ensemble Transform Kalman Filter (ETKF) to assimilate observations and predict flow reversals. We show that using adaptively shaped localized covariance outperforms static localized covariance with the ETKF, and allows for the use of less observations in predicting flow reversals. We also show that a Dynamic Mode Decomposition (DMD) of the temperature and velocity fields recovers the low dimensional system underlying reversals, finding specific modes which together are predictive of reversal direction. PMID:26849061

  12. Experimental study of stability and transients in a horizontally heated boiling helium thermosyphon

    NASA Astrophysics Data System (ADS)

    Furci, H.; Four, A.; Baudouy, B.

    2015-12-01

    Experiments were conducted on a liquid helium natural circulation loop with a 4 m long horizontal heated section. Wall temperatures on the heated section, mass flow rate and pressure drop were measured in steady and transient regimes. The stability of the loop has been studied and the power stability limits have been found. Also, different heating configurations were explored and their drawbacks and benefits were observed. The result is that the loop is stable only above a non-zero low power and below a certain upper power limit. The distance from the heating to the vertical riser affects the stability range. It has been found that instabilities at low power or transients following a low power step pulse can produce considerable temperature oscillations, potentially dangerous from the magnet protection point of view.

  13. Use of LHP for cooling power electronic components

    NASA Astrophysics Data System (ADS)

    Smitka, M.; Malcho, M.; Nemec, P.; Kolková, Z.

    2013-04-01

    The paper deals with use of cooling equipment build on basis two phase thermosyphon loop. This device belongs to a group of loop heat pipe (LHP). This LHP is a two-phase device with extremely high effective thermal conductivity that utilizes the thermodynamic pressure difference to circulate fluid. It was invented in Russia in the early 1980´s. Thermosyphon loop is similar as LHP but it doesn't contain wick and circulation of the fluid using gravitation force instead of capillary pressure as it is in LHP. The work deals with the cooling insulated gate bipolar transistor with 370 W. The paper describes the course of the heat dissipation using ribbed cooler for natural convection and using fin for forced convection. The results are compared with heat dissipation through thermosyphon loop.

  14. Comparison of six generic solar domestic hot water systems

    SciTech Connect

    Farrington, R.B.; Murphy, L.M.; Noreen, D.L.

    1980-04-01

    The cost effectiveness of residential solar water heating is explored by analyzing six different system types. A figure of merit (that considers both performance and cost) is calculated for each system, providing information for both researchers and industry. Thermosyphon water heaters are determined to be the most cost effective option, and their wider application is recommended once a reliable draindown technique is developed.

  15. Engineering Design Elements of a Two-Phase Thermosyphon to Trannsfer NGNP Nuclear Thermal Energy to a Hydrogen Plant

    SciTech Connect

    Piyush Sabharwal

    2009-07-01

    Two hydrogen production processes, both powered by a Next Generation Nuclear Plant (NGNP), are currently under investigation at Idaho National Laboratory. The first is high-temperature steam electrolysis, which uses both heat and electricity; the second is thermo-chemical production through the sulfur iodine process primarily using heat. Both processes require a high temperature (>850°C) for enhanced efficiency; temperatures indicative of the NGNP. Safety and licensing mandates prudently dictate that the NGNP and the hydrogen production facility be physically isolated, perhaps requiring separation of over 100 m.

  16. Numerical solution of fluid flow and heat tranfer problems with surface radiation

    NASA Technical Reports Server (NTRS)

    Ahuja, S.; Bhatia, K.

    1995-01-01

    This paper presents a numerical scheme, based on the finite element method, to solve strongly coupled fluid flow and heat transfer problems. The surface radiation effect for gray, diffuse and isothermal surfaces is considered. A procedure for obtaining the view factors between the radiating surfaces is discussed. The overall solution strategy is verified by comparing the available results with those obtained using this approach. An analysis of a thermosyphon is undertaken and the effect of considering the surface radiation is clearly explained.

  17. 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

    2015-07-01

    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.

  18. Experimental investigation of passive residual heat removal system with air cooled heat exchanger

    SciTech Connect

    Cha, J.H.; Chung, M.K.; Jun, H.G.

    1996-08-01

    The objective of this work is to obtain the Performance test data for the passive residual heat removal (RHR) heat exchanger in the advanced PWR. The RHR heat exchanger is designed to remove the decay heat with combined effects of the natural circulation of water by means of the thermosyphon at the inside and the natural convection of the air at the outside. Two test models were made to simulate the RHR heat exchanger. The one is the single bundle test model which consisted of a finned tubular heat exchanger unit. The other is the multi-bundle test model which has the finned tubular heat exchanger consisting of ten bundles of tubular units. The Maximum heat removal capabilities of each model were investigated. The cooling water flow rates by the thermosyphon were measured and were in good agreement with the theoretical predictions. The effects of chimney and elevation between the heater and the heat exchanger were investigated.

  19. Simulation of natural convection in a rectangular loop using finite elements

    SciTech Connect

    Pepper, D W; Hamm, L L; Kehoe, A B

    1984-01-01

    A two-dimensional finite-element analysis of natural convection in a rectangular loop is presented. A psi-omega formulation of the Boussinesque approximation to the Navier-Stokes equation is solved by the false transient technique. Streamlines and isotherms at Ra = 10/sup 4/ are shown for three different modes of heating. The results indicate that corner effects should be considered when modeling flow patterns in thermosyphons.

  20. Comparison of natural convection heat exchangers for solar water heating systems

    SciTech Connect

    Davidson, J.; Liu, W.

    1998-09-15

    Thermosyphon heat exchangers are used in indirect solar water heating systems to avoid using a pump to circulate water from the storage tank to the heat exchanger. In this study, the authors consider the effect of heat exchanger design on system performance. They also compare performance of a system with thermosyphon flow to the same system with a 40W pump in the water loop. In the first part of the study, the authors consider the impact of heat exchanger design on the thermal performance of both one- and two-collector solar water heaters. The comparison is based on Solar Rating and Certification Corporation (SRCC) OG300 simulations. The thermosyphon heat exchangers considered are (1) a one-pass, double wall, 0.22 m{sup 2}, four tube-in-shell heat exchanger manufactured by AAA Service and Supply, Inc., (the Quad-Rod); (2) a two-pass, double wall, 0.2 m{sup 2}, tube-in-shell made by Heliodyne, Inc., but not intended for commercial development; (3) a one-pass, single wall, 0.28 m{sup 2}, 31 tube-in-shell heat exchanger from Young Radiator Company, and (4) a one-pass single-wall, 0.61 m{sup 2}, four coil-in-shell heat exchanger made by ThermoDynamics Ltd. The authors compare performance of the systems with thermosyphon heat exchangers to a system with a 40 W pump used with the Quad-Rod heat exchanger. In the second part of the study, the effects of reducing frictional losses through the heat exchanger and/or the pipes connecting the heat exchanger to the storage tank, and increasing heat transfer area are evaluated in terms of OG300 ratings.

  1. Natural convection heat exchangers for solar water heating systems. Technical progress report, September 15, 1996--November 14, 1996

    SciTech Connect

    Davidson, J.H.

    1998-06-01

    The goals of this project are: (1) to develop guidelines for the design and use of thermosyphon side-arm heat exchangers in solar domestic water heating systems, and (2) to establish appropriate modeling and testing criteria for evaluating the performance of systems using this type of heat exchanger. The tasks for the project are as follows: (1) Develop a model of the thermal performance of thermosyphon heat exchangers in solar water heating applications. A test protocol will be developed which minimizes the number of tests required to adequately account for mixed convection effects. The TRNSYS component model will be fully integrated in a system component model and will use data acquired with the specified test protocol. (2) Conduct a fundamental study to establish friction and heat transfer correlations for conditions and geometries typical of thermosyphon heat exchangers in solar systems. Data will be obtained as a function of a buoyancy parameter based on Grashof and Reynolds numbers. The experimental domain will encompass the ranges expected in solar water heating systems.

  2. Are Effective Properties Effective?

    SciTech Connect

    Han, Ru; Ingber, Marc S.; Hsiao, S.-C.

    2008-02-15

    The effective moduli (effective Young's modulus, effective Poisson's ratio, effective shear modulus, and effective bulk modulus) of dispersed-phase-reinforced composite materials are determined at the mesoscopic level using three-dimensional parallel boundary element simulations. By comparing the mesoscopic BEM results and the macroscopic results based on effective properties, limitations in the effective property approach have been examined.

  3. Research and development of long heat pipes and their applications

    NASA Astrophysics Data System (ADS)

    Takaoka, M.; Mohtai, T.; Mochizuki, M.; Mashiko, K.

    1984-03-01

    A 40 m thermosyphon type flexible corrugated heat pipe was constructed and its heat transfer characteristics were measured. The flooding phenomenon was quantitatively observed using electronic stethoscopes, and its influence to the heat transfer characteristics was determined. The particular features of the road heating system using long heat pipes are: (1) there is no possibility of water leaking and their maintenance is easy; (2) they endure heavy loads, thermal stresses, vibrations and ground subsidence; (3) the heat transfering surface area of the heat pipes is so large that it is particularly effective for heating through small temperature difference; and (4) the installation is easy and inexpensive.

  4. Research and Development for Novel Thermal Energy Storage Systems (TES) for Concentrating Solar Power (CSP)

    SciTech Connect

    Faghri, Amir; Bergman, Theodore L; Pitchumani, Ranga

    2013-09-26

    The overall objective was to develop innovative heat transfer devices and methodologies for novel thermal energy storage systems for concentrating solar power generation involving phase change materials (PCMs). Specific objectives included embedding thermosyphons and/or heat pipes (TS/HPs) within appropriate phase change materials to significantly reduce thermal resistances within the thermal energy storage system of a large-scale concentrating solar power plant and, in turn, improve performance of the plant. Experimental, system level and detailed comprehensive modeling approaches were taken to investigate the effect of adding TS/HPs on the performance of latent heat thermal energy storage (LHTES) systems.

  5. Side Effects

    MedlinePLUS

    ... 2014 Select a Language: Fact Sheet 550 Side Effects WHAT ARE SIDE EFFECTS? WHO GETS SIDE EFFECTS? ... t assume that you will get every side effect that’s listed! Most people have few or only ...

  6. Managerial Effectiveness.

    ERIC Educational Resources Information Center

    Reddin, William J.

    A conceptual framework (3-D theory of managerial effectiveness) which relates the effectiveness of managerial style to specific situations is provided in this book. The six parts of the book are as follows: 1. Key Concepts, 2. Situation, 3. Styles, 4. Flex, 5. Managerial Effectiveness, and 6. Organizational Effectiveness. The book contains many…

  7. Chemotherapy Effects

    MedlinePLUS

    ... saved articles window. My Saved Articles » My ACS » Chemotherapy Side Effects Chemotherapy drugs are powerful medicines that can cause side ... on the side effects most commonly caused by chemotherapy, this is a good place to start. Managing ...

  8. Placebo Effect

    MedlinePLUS

    ... C. Spencer, MD Steven Karceski, MD The placebo effect Joseph H. Friedman, MD Richard Dubinsky, MD WHAT ... placebo: a “dummy” medication that should have no effect on the condition. Placebos are not only drugs. ...

  9. Gravity Scaling of a Power Reactor Water Shield

    NASA Astrophysics Data System (ADS)

    Reid, Robert S.; Pearson, J. Boise

    2008-01-01

    Water based reactor shielding is being considered as an affordable option for potential use on initial lunar surface reactor power systems. Heat dissipation in the shield from nuclear sources must be rejected by an auxillary thermal hydraulic cooling system. The mechanism for transferring heat through the shield is natural convection between the core surface and an array of thermosyphon radiator elements. Natural convection in a 100 kWt lunar surface reactor shield design has been previously evaluated at lower power levels (Pearson, 2006). The current baseline assumes that 5.5 kW are dissipated in the water shield, the preponderance on the core surface, but with some volumetric heating in the naturally circulating water as well. This power is rejected by a radiator located above the shield with a surface temperature of 370 K. A similarity analysis on a water-based reactor shield is presented examining the effect of gravity on free convection between a radiation shield inner vessel and a radiation shield outer vessel boundaries. Two approaches established similarity: 1) direct scaling of Rayleigh number equates gravity-surface heat flux products, 2) temperature difference between the wall and thermal boundary layer held constant on Earth and the Moon. Nussult number for natural convection (laminar and turbulent) is assumed of form Nu = CRan. These combined results estimate similarity conditions under Earth and Lunar gravities. The influence of reduced gravity on the performance of thermosyphon heat pipes is also examined.

  10. Gravity Scaling of a Power Reactor Water Shield

    SciTech Connect

    Reid, Robert S.; Pearson, J. Boise

    2008-01-21

    Water based reactor shielding is being considered as an affordable option for potential use on initial lunar surface reactor power systems. Heat dissipation in the shield from nuclear sources must be rejected by an auxillary thermal hydraulic cooling system. The mechanism for transferring heat through the shield is natural convection between the core surface and an array of thermosyphon radiator elements. Natural convection in a 100 kWt lunar surface reactor shield design has been previously evaluated at lower power levels (Pearson, 2006). The current baseline assumes that 5.5 kW are dissipated in the water shield, the preponderance on the core surface, but with some volumetric heating in the naturally circulating water as well. This power is rejected by a radiator located above the shield with a surface temperature of 370 K. A similarity analysis on a water-based reactor shield is presented examining the effect of gravity on free convection between a radiation shield inner vessel and a radiation shield outer vessel boundaries. Two approaches established similarity: 1) direct scaling of Rayleigh number equates gravity-surface heat flux products, 2) temperature difference between the wall and thermal boundary layer held constant on Earth and the Moon. Nussult number for natural convection (laminar and turbulent) is assumed of form Nu = CRa{sup n}. These combined results estimate similarity conditions under Earth and Lunar gravities. The influence of reduced gravity on the performance of thermosyphon heat pipes is also examined.

  11. Design and Performance of a Hybrid PV/T Solar Water Heater

    NASA Astrophysics Data System (ADS)

    Tripanagnostopoulos, Y.; Souliotis, M.; Makris, Th.; Georgostathis, P.; Sarris, M.

    2010-01-01

    In this paper we present design considerations and experimental results of a thermosyphonic hybrid PV/T solar system that is investigated at the University of Patras. Hybrid PV/T systems can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We tested outdoors PV/T prototypes consisted of pc-Si PV modules and heat exchanger of copper sheet with copper pipes, for two system types (PVT/UNGL and PVT/GL). We used commercial PV modules, which give about 12%-15% efficiency, depending on the operating temperature and the use or not of additional glazing. During the experiments the generated electricity was transmitted to a load, simulating real system operation. Steady state tests of the system were performed outdoors to determine collector thermal efficiency. The glazed PV/T collector presents remarkably higher thermal output than the unglazed PV/T collector, but the electrical output of it is reduced due to additional optical losses. The experimental study of the tested thermosyphonic hybrid PV/T solar device showed that it can perform effectively during all year long, achieving at least 40° C of hot water and producing electricity at a satisfactory level.

  12. Gravity Scaling of a Power Reactor Water Shield

    NASA Technical Reports Server (NTRS)

    Reid, Robert S.; Pearson, J. Boise

    2008-01-01

    Water based reactor shielding is being considered as an affordable option for use on initial lunar surface power systems. Heat dissipation in the shield from nuclear sources must be rejected by an auxiliary thermal hydraulic cooling system. The mechanism for transferring heat through the shield is natural convection between the core surface and an array of thermosyphon radiator elements. Natural convection in a 100 kWt lunar surface reactor shield design has been previously evaluated at lower power levels (Pearson, 2007). The current baseline assumes that 5.5 kW are dissipated in the water shield, the preponderance on the core surface, but with some volumetric heating in the naturally circulating water as well. This power is rejected by a radiator located above the shield with a surface temperature of 370 K. A similarity analysis on a water-based reactor shield is presented examining the effect of gravity on free convection between a radiation shield inner vessel and a radiation shield outer vessel boundaries. Two approaches established similarity: 1) direct scaling of Rayleigh number equates gravity-surface heat flux products, 2) temperature difference between the wall and thermal boundary layer held constant on Earth and the Moon. Nussult number for natural convection (laminar and turbulent) is assumed of form Nu = CRa(sup n). These combined results estimate similarity conditions under Earth and Lunar gravities. The influence of reduced gravity on the performance of thermosyphon heat pipes is also examined.

  13. Thermal Effects.

    ERIC Educational Resources Information Center

    Talmage, Sylvia S.; Coutant, Charles C.

    1978-01-01

    Presents a literature review of the effect of temperature on the biosphere water, covering publications of 1976-77. This review includes the effects of temperature on growth, production, and embryonic and larval development. A list of 401 references is also presented. (HM)

  14. Gauging Effectiveness

    ERIC Educational Resources Information Center

    Foord, Kathleen A.; Haar, Jean M.

    2012-01-01

    Books by education experts and speakers at national professional conferences have inspired many school leaders to initiate professional learning communities (PLCs). Sustaining them effectively to raise student achievement is another matter. How can one know whether a PLC is moving toward a desired outcome? Measuring effectiveness requires an…

  15. Thermal effects

    SciTech Connect

    Harrelson, M.E.; Talmadge, S.S.; Cravens, J.B.

    1984-06-01

    A literature review is presented of recent studies on the role of temperature effects and change in temperature caused by thermal power plants on aquatic life. Several of these studies involve the use of models that allow testing of hypotheses concerning the effects of temperature on fish and insects. 91 references.

  16. Thermal effects

    SciTech Connect

    Cravens, J.B.; Harrelson, M.E.; Talmage, S.S.

    1983-06-01

    A literature review of studies dealing with thermal effects on aquatic systems is presented. Site studies are discussed, along with biochemical reaction studies, the effects of temperature on the growth of organisms, and the interaction of temperature and other stresses. (JMT)

  17. Psychopharmaceuticals: effects and side effects

    PubMed Central

    Kline, Nathan S.

    1959-01-01

    Drugs which affect psychological behaviour are being used in vast amounts nowadays, with, in all too many cases, but scant regard for their exact uses or possible side effects. This article contains a clinical classification of these drugs, followed by an account of their principal side effects and the means of obviating them. PMID:14409889

  18. Effective Schools Require Effective Principals

    ERIC Educational Resources Information Center

    LaPointe, Michelle; Davis, Stephen H.

    2006-01-01

    At long last, scholars and policy makers have come to realize what most school administrators have known for years--that effective schools require both outstanding teachers and strong leaders. Although there is considerable research about the characteristics of effective school leaders and the strategies principals can use to help manage…

  19. Health Effects

    MedlinePLUS

    ... Search The CDC Cancel Submit Search The CDC Climate and Health Note: Javascript is disabled or is ... Guidance and Trainings Webinars Data and Tools Publications Climate Effects on Health Recommend on Facebook Tweet Share ...

  20. Measuring effectiveness.

    PubMed

    Stegenga, Jacob

    2015-12-01

    Measuring the effectiveness of medical interventions faces three epistemological challenges: the choice of good measuring instruments, the use of appropriate analytic measures, and the use of a reliable method of extrapolating measures from an experimental context to a more general context. In practice each of these challenges contributes to overestimating the effectiveness of medical interventions. These challenges suggest the need for corrective normative principles. The instruments employed in clinical research should measure patient-relevant and disease-specific parameters, and should not be sensitive to parameters that are only indirectly relevant. Effectiveness always should be measured and reported in absolute terms (using measures such as 'absolute risk reduction'), and only sometimes should effectiveness also be measured and reported in relative terms (using measures such as 'relative risk reduction')-employment of relative measures promotes an informal fallacy akin to the base-rate fallacy, which can be exploited to exaggerate claims of effectiveness. Finally, extrapolating from research settings to clinical settings should more rigorously take into account possible ways in which the intervention in question can fail to be effective in a target population. PMID:26199055

  1. Evaluating Heat Pipe Performance in 1/6 g Acceleration: Problems and Prospects

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; McCollum, Timothy A.; Gibson, Marc A.; Sanzi, James L.; Sechkar, Edward A.

    2011-01-01

    Heat pipes composed of titanium and water are being considered for use in the heat rejection system of a fission power system option for lunar exploration. Placed vertically on the lunar surface, the heat pipes would operate as thermosyphons in the 1/6 g environment. The design of thermosyphons for such an application is determined, in part, by the flooding limit. Flooding is composed of two components, the thickness of the fluid film on the walls of the thermosyphon and the interaction of the fluid flow with the concurrent vapor counter flow. Both the fluid thickness contribution and interfacial shear contribution are inversely proportional to gravity. Hence, evaluating the performance of a thermosyphon in a 1 g environment on Earth may inadvertently lead to overestimating the performance of the same thermosyphon as experienced in the 1/6 g environment on the moon. Several concepts of varying complexity have been proposed for evaluating thermosyphon performance in reduced gravity, ranging from tilting the thermosyphons on Earth based on a cosine function, to flying heat pipes on a low-g aircraft. This paper summarizes the problems and prospects for evaluating thermosyphon performance in 1/6 g.

  2. Effects and Effectiveness of Telemedicine

    PubMed Central

    Grigsby, Jim; Kaehny, Margaret M.; Sandberg, Elliot J.; Schlenker, Robert E.; Shaughnessy, Peter W.

    1995-01-01

    The use of telemedicine has recently undergone rapid growth and proliferation. Although the feasibility of many applications has been tested for nearly 30 years, data concerning the costs, effects, and effectiveness of telemedicine are limited. Consequently, the development of a strategy for coverage, payment, and utilization policy has been hindered. Telemedicine continues to expand, and pressure for policy development increases in the context of Federal budget cuts and major changes in health service financing. This article reviews the literature on the effects and medical effectiveness of telemedicine. It concludes with several recommendations for research, followed by a discussion of several specific questions, the answers to which might have a bearing on policy development. PMID:10153466

  3. Plasma Effects

    NASA Technical Reports Server (NTRS)

    Armstrong, J. W.

    1983-01-01

    Radio communication with space probes requires sending signals through the Earth's ionosphere and usually the solar wind. During planetary flybys, the signal may also pass through the ionosphere of another planet. These ionized media can perturb the radio signal in a variety of ways. Examples of these perturbations are variations in the electrical length between the spacecraft and the ground station, Faraday rotation of linearly polarized signals, amplitude and phase scintillations, and spectral and angular broadening. These plasma effects can have undesirable influences on telemetry performance and thus need to be understood from a communications engineering viewpoint. The plasma effects are, however, useful from a scientific viewpoint, since the effects on the communications link can often be inverted to estimate the physical conditions in the plasma.

  4. Physiological effects

    SciTech Connect

    Pearcy, R.W.; Bjoerkman, O.

    1983-01-01

    This chapter examines the effects of CO/sub 2/ on plants at the physiological level. The authors examine the potential effects of elevated CO/sub 2/ in concert with water, temperature, light, and salinity. They also examine plant allometric growth as it is affected by CO/sub 2/. The relationships between CO/sub 2/ uptake and temperature are examined in some detail. Stomatal function as it is now known is discussed, along with changes in water use efficiency correlated with increased levels of CO/sub 2/. Future research needs are identified. 71 references, 8 figures.

  5. Sleeper Effects

    ERIC Educational Resources Information Center

    Maurer, Daphne; Mondloch, Catherine J.; Lewis, Terri L.

    2007-01-01

    Early experience preserves and refines many capabilities that emerge prenatally. Here we describe another role that it plays--establishing the neural substrate for capabilities that emerge at a much later point in development. The evidence comes from sleeper effects: permanent deficits when early experience was absent in capabilities that normally…

  6. Effective Evaluation

    ERIC Educational Resources Information Center

    Oliva, Michelle; Mathers, Carrie; Laine, Sabrina

    2009-01-01

    Principals know that effective teachers are the greatest school-based contributors to improved student outcomes. What is not always clear is how principals can help teachers adapt their instructional practices to the increasingly diverse learning styles they find in their classrooms. Teacher evaluation practices are typically not seen as a tool…

  7. Effective Consumerism.

    ERIC Educational Resources Information Center

    Daugherty, Mabel

    This module, consisting of materials for use in conducting a consumer education mini-course, deals with effective consumerism. Covered in the individual lessons are the following topics: being prepared with information (sources of consumer information and subscription forms); evaluating warranties and service contracts; evaluating advertising and…

  8. Communicating Effectively

    Cancer.gov

    The seventh module of the EPEC-O (Education in Palliative and End-of-Life Care for Oncology) Self-Study: Cultural Considerations When Caring for African Americans explores communication issues pertinent to African Americans with cancer and their health care providers, discusses strategies for culturally sensitive communication, and presents the SPIKES protocol, a practical framework for effective communication.

  9. Sleeper Effects

    ERIC Educational Resources Information Center

    Maurer, Daphne; Mondloch, Catherine J.; Lewis, Terri L.

    2007-01-01

    Early experience preserves and refines many capabilities that emerge prenatally. Here we describe another role that it plays--establishing the neural substrate for capabilities that emerge at a much later point in development. The evidence comes from sleeper effects: permanent deficits when early experience was absent in capabilities that normally…

  10. System Effectiveness

    SciTech Connect

    Powell, Danny H; Elwood Jr, Robert H

    2011-01-01

    An effective risk assessment system is needed to address the threat posed by an active or passive insider who, acting alone or in collusion, could attempt diversion or theft of nuclear material. It is critical that a nuclear facility conduct a thorough self-assessment of the material protection, control, and accountability (MPC&A) system to evaluate system effectiveness. Self-assessment involves vulnerability analysis and performance testing of the MPC&A system. The process should lead to confirmation that mitigating features of the system effectively minimize the threat, or it could lead to the conclusion that system improvements or upgrades are necessary to achieve acceptable protection against the threat. Analysis of the MPC&A system is necessary to understand the limits and vulnerabilities of the system to internal threats. Self-assessment helps the facility be prepared to respond to internal threats and reduce the risk of theft or diversion of nuclear material. MSET is a self-assessment or inspection tool utilizing probabilistic risk assessment (PRA) methodology to calculate the system effectiveness of a nuclear facility's MPC&A system. MSET analyzes the effectiveness of an MPC&A system based on defined performance metrics for MPC&A functions based on U.S. and international best practices and regulations. A facility's MC&A system can be evaluated at a point in time and reevaluated after upgrades are implemented or after other system changes occur. The total system or specific subareas within the system can be evaluated. Areas of potential performance improvement or system upgrade can be assessed to determine where the most beneficial and cost-effective improvements should be made. Analyses of risk importance factors show that sustainability is essential for optimal performance. The analyses reveal where performance degradation has the greatest detrimental impact on total system risk and where performance improvements have the greatest reduction in system risk. The risk importance factors show the amount of risk reduction achievable with potential upgrades and the amount of risk reduction actually achieved after upgrades are completed. Applying the risk assessment tool gives support to budget prioritization by showing where budget support levels must be sustained for MC&A functions most important to risk. Results of the risk assessment are also useful in supporting funding justifications for system improvements that significantly reduce system risk.

  11. Comparison of the effects of Al2O3 and CuO nanoparticles on the performance of a solar flat-plate collector

    NASA Astrophysics Data System (ADS)

    Munuswamy, Dinesh Babu; Madhavan, Venkata Ramanan; Mohan, Mukunthan

    2015-12-01

    To improve the efficiency of solar flat-plate collectors further, a study had been carried out wherein the conventional working fluid was replaced by nanofluids. A 25-L/day solar flat-plate water heater with collector area of 0.5 {m}^2 has been designed and fabricated. The thermosyphon system of the solar water heater was monitored at 15 locations using T-type thermocouples. Alumina and CuO nanoparticles were synthesized and characterized using Brunauer-Emmett-Teller and X-ray diffraction techniques and dispersed using ultrasonic mechanism. To stabilize the system at an optimum level, the collector is operated with volume fractions of 0.2% and 0.4% of synthesized Al2O3 and CuO nanoparticles mixed with distilled water and used in the solar flat-plate collector. The temperature profile was compared with different volume fractions of the nanoparticles in the flowing medium. Enhanced heat transfer was observed in the solar flat-plate collector using nanoparticles, and hence, it is inferred that addition of nanoparticles improves the efficiency of the solar water heaters. This paper details the temperature profile observed in the collectors, variation of insolation over the day, and change in efficiency both on the primary side (collector) and on the secondary side (storage tank) of the solar water heater.

  12. Radiation effects

    SciTech Connect

    Holden, N.E.

    1985-01-01

    For the meeting of the Commission on Radiochemistry and Nuclear Techniques our chairman has submitted comments on potential problems that the Commission should consider in Lyon which had been posed by various members. In one of these comments, Prof. Roth has mentioned the problem of radiation effects in solids and in water and water solutions. The radiolysis of water has been of concern for a large number of years, but as Prof. Roth notes, the radiation effects on the first wall of fusion reactors is a problem that has arisen only in recent years and for which no critical data compilation is presently available. This paper has been prepared in response to Prof. Roth's comments and indicates a possible area, which the Commission might conceivably address at this meeting and/or in the near future. 7 refs.

  13. Blazhko Effect

    NASA Technical Reports Server (NTRS)

    Teays, Terry

    1996-01-01

    The cause of the Blazhko effect, the long-term modulation of the light and radial velocity curves of some RR Lyr stars, is still not understood. The observational characteristics of the Blazhko effect are discussed. Some preliminary results are presented from two recent campaigns to observe RR Lyr, using the International Ultraviolet Explorer along with ground-based spectroscopy and photometry, throughout a pulsation cycle, at a variety of Blazhko phases. A set of ultraviolet light curves have been generated from low dispersion IUE spectra. In addition, the (visual) light curves from IUE's Fine Error Sensor are analyzed using the Fourier decomposition technique. The values of the parameters Psi(sub 21) and R(sub 21) at different Blazhko phases of RR Lyr span the range of values found for non-Blazhko variables of similar period.

  14. Effective Presentations

    PubMed Central

    Spooner, H. James; Swanson, Richard W.

    1990-01-01

    Where the purpose of presentations is to inform, effective delivery is important to ensure that audiences receive the educational message. We offer six suggestions: introduce the topic in an interesting way; speak loudly enough; do not read; involve the audience actively; respect the attention span of the audience; and limit the amount of content. We conclude that the skills of live public presentation can be learned, but that the art of presentation is innate. Imagesp2063-ap2064-a PMID:21233951

  15. Erosion Effects

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    The impact crater in this THEMIS image is a model illustration to the effects of erosion on Mars. The degraded crater rim and several landslides observed in crater walls is evidence to the mass wasting of materials. Layering in crater walls also suggests the presence of materials that erode at varying rates.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 31.6, Longitude 44.3 East (315.7 West). 19 meter/pixel resolution.

  16. Side Effects of Chemotherapy

    MedlinePLUS

    ... Men Living with Prostate Cancer Side Effects of Chemotherapy Side Effects Urinary Dysfunction Bowel Dysfunction Erectile Dysfunction ... Side Effects of Hormone Therapy Side Effects of Chemotherapy Side Effects: When to Seek Help PSA Rising ...

  17. Efficiency study of oil cooling of a screw compressor

    SciTech Connect

    Tree, D.R.; McKellar, M.G. . Ray W. Herrick Labs.); Fresco, A. )

    1990-01-01

    One of the major goals of all compressor manufacturers is to design and build as efficient a compressor as possible. In a screw compressor it appears that the way the compressor is cooled can have an effect on the compressor's efficiency. This paper presents experimental data on three different screw compressor cooling methods: Liquid Refrigerant Injection Cooling System; Thermosyphon Cooling System; and Oil Injection System. All tests were conducted on a hot gas bypass system using refrigerant R-22. The data taken shows that the Oil Injection System is slightly better than the other two. These tests should be repeated with a higher oil flow rate and ammonia as the working fluid. 10 figs.

  18. Efficiency study of oil cooling of a screw compressor

    SciTech Connect

    Tree, D.R.; McKellar, M.G.

    1989-04-01

    One of the major goals of all compressor manufacturers is to build as efficient a compressor as possible. Over the last several years improvements to the design of screw compressors has made them efficiently competitive with other types of compressors, especially at large loads. The primary purpose of this research is to investigate four different methods of cooling a 250 horsepower compressor and determine their effects on the efficiency of the compressor. Two conventional methods, liquid injection and thermosyphon cooling, and two new methods, V-PLUS and Fresco oil injection, are investigated. The screw compressor used in the tests was a VRS-500 screw compressor made by the Vilter Manufacturing Corporation. 6 figs.

  19. LUX0.1 Prototype Results: Cryogenics and Circulation

    NASA Astrophysics Data System (ADS)

    Bradley, Adam

    2010-02-01

    LUX is a new dark matter direct detection experiment to be carried out at the Sanford Lab, the renewed underground facility at the Homestake mine in Lead, SD. The detector's large size supports effective internal shielding from natural radioactivity of the surrounding materials and environment. The LUX detector consists of a cylindrical vessel containing 350 kg of liquid xenon (LXe) cooled down using a novel cryogenic system. We tested a small-scale four PMT prototype utilizing over 300 gm of active xenon, installed in the full-sized cryostat. We report the efficiency of a unique internal heat exchanger with standard gas phase purification using a heated getter, which allows for very high flow purification without requiring large cooling power, as well as the efficiency of a thermosyphon-based cooling system. Such systems are required for multi-ton scale up. )

  20. LUX Cryogenics and Circulation

    NASA Astrophysics Data System (ADS)

    Bradley, Adam

    2012-10-01

    LUX is a new dark matter direct detection experiment being carried out at the Sanford Underground Research Facility, at the renewed Homestake mine in Lead, SD. The detector's large size supports effective internal shielding from natural radioactivity of the surrounding materials and environment. The LUX detector consists of a cylindrical vessel containing 350 kg of liquid xenon (LXe) cooled down and maintained at 175-K operating temperature using a novel cryogenic system. We report the efficiency of our thermosyphon-based cooling system, as well as the efficiency of a unique internal heat exchanger with standard gas phase purification using a heated getter, which allows for very high flow purification without requiring large cooling power. Such systems are required for multi-ton scale up.

  1. Effective Teaching/Effective Urban Teaching

    ERIC Educational Resources Information Center

    Watson, Dyan; Charner-Laird, Megin; Kirkpatrick, Cheryl L.; Szczesiul, Stacy Agee; Gordon, Pamela J.

    2006-01-01

    This article considers the ways in which 17 novice teachers define and describe effective urban teaching and the stark contrasts that these teachers draw between effective urban teaching and effective teaching. The authors find that descriptions of students played a considerable role when participants made distinctions between effective teaching…

  2. Lunar Dust Biological Effects

    NASA Astrophysics Data System (ADS)

    Jones, L.; Jacques, S.; Rask, J. C.; Tranfield, E.; Taylor, L.; Kerschmann, R.; Loftus, D. J.

    2008-07-01

    We are investigating the biological effects of lunar dust collected during the Apollo missions to understand potential skin effects, inhalation toxicity, and ocular effects that may result from long duration human habitation of the Moon.

  3. Communicating Effectively PDF

    Cancer.gov

    Effective communication is essential for the delivery of quality cancer palliative care. And yet, healthcare providers often lack the skills to communicate effectively with their patients and families.

  4. Effects of Anesthesia

    MedlinePLUS

    ... Anesthesia Surgery Risks Anesthesia Awareness Obesity and Anesthesia Sleep Apnea and Anesthesia Smoking and Anesthesia Outpatient Surgery Effects of Anesthesia Side effects of anesthesia can occur ...

  5. On Effect Size

    ERIC Educational Resources Information Center

    Kelley, Ken; Preacher, Kristopher J.

    2012-01-01

    The call for researchers to report and interpret effect sizes and their corresponding confidence intervals has never been stronger. However, there is confusion in the literature on the definition of effect size, and consequently the term is used inconsistently. We propose a definition for effect size, discuss 3 facets of effect size (dimension,…

  6. [Adverse effects of marijuana].

    PubMed

    Mallaret, Michel; Dal'Bo-Rohrer, Dominique; Demattéis, Maurice

    2005-01-15

    When admitted in an emergency unit, young patients often present acute neurological effects of smoked marijuana. Other chronic adverse effects of marijuana are probably underestimated: postural syncope, arteritis, chronic bronchitis, amnesia. Marijuana may trigger a myocardial infarction and have a vasospastic effect. Marijuana has impairing effects on driving ability. Smoked marijuana is a potential respiratory tract carcinogen. PMID:15801396

  7. Improving School Effectiveness.

    ERIC Educational Resources Information Center

    MacBeath, John, Ed.; Mortimore, Peter, Ed.

    School effectiveness is an issue that has preoccupied researchers and policymakers for 3 decades. To study how ineffective schools become effective and what constitutes an effective school, the Improving School Effectiveness Project was carried out in Scotland from 1995 to 1997. This project forms the basis of discussion in this book, which has 11…

  8. Water-storage-tube systems. Final report

    SciTech Connect

    Hemker, P.

    1981-12-24

    Passive solar collection/storage/distribution systems were surveyed, designed, fabricated, and mechanically and thermally tested. The types studied were clear and opaque fiberglass tubes, metal tubes with plastic liners, and thermosyphoning tubes. (MHR)

  9. Gravitational Casimir Effect

    NASA Astrophysics Data System (ADS)

    Quach, James Q.

    2015-02-01

    We derive the gravitonic Casimir effect with nonidealized boundary conditions. This allows the quantification of the gravitonic contribution to the Casimir effect from real bodies. We quantify the meagerness of the gravitonic Casimir effect in ordinary matter. We also quantify the enhanced effect produced by the speculated Heisenberg-Couloumb (HC) effect in superconductors, thereby providing a test for the validity of the HC theory, and, consequently, the existence of gravitons.

  10. Gravitational Casimir effect.

    PubMed

    Quach, James Q

    2015-02-27

    We derive the gravitonic Casimir effect with nonidealized boundary conditions. This allows the quantification of the gravitonic contribution to the Casimir effect from real bodies. We quantify the meagerness of the gravitonic Casimir effect in ordinary matter. We also quantify the enhanced effect produced by the speculated Heisenberg-Couloumb (HC) effect in superconductors, thereby providing a test for the validity of the HC theory, and, consequently, the existence of gravitons. PMID:25768749

  11. On effect size.

    PubMed

    Kelley, Ken; Preacher, Kristopher J

    2012-06-01

    The call for researchers to report and interpret effect sizes and their corresponding confidence intervals has never been stronger. However, there is confusion in the literature on the definition of effect size, and consequently the term is used inconsistently. We propose a definition for effect size, discuss 3 facets of effect size (dimension, measure/index, and value), outline 10 corollaries that follow from our definition, and review ideal qualities of effect sizes. Our definition of effect size is general and subsumes many existing definitions of effect size. We define effect size as a quantitative reflection of the magnitude of some phenomenon that is used for the purpose of addressing a question of interest. Our definition of effect size is purposely more inclusive than the way many have defined and conceptualized effect size, and it is unique with regard to linking effect size to a question of interest. Additionally, we review some important developments in the effect size literature and discuss the importance of accompanying an effect size with an interval estimate that acknowledges the uncertainty with which the population value of the effect size has been estimated. We hope that this article will facilitate discussion and improve the practice of reporting and interpreting effect sizes. PMID:22545595

  12. Phase Change Heat Transfer Device for Process Heat Applications

    SciTech Connect

    Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

    2010-10-01

    The next generation nuclear plant (NGNP) will most likely produce electricity and process heat, with both being considered for hydrogen production. To capture nuclear process heat, and transport it to a distant industrial facility requires a high temperature system of heat exchangers, pumps and/or compressors. The heat transfer system is particularly challenging not only due to the elevated temperatures (up to approx.1300 K) and industrial scale power transport (=50MW), but also due to a potentially large separation distance between the nuclear and industrial plants (100+m) dictated by safety and licensing mandates. The work reported here is the preliminary analysis of two-phase thermosyphon heat transfer performance with alkali metals. A thermosyphon is a thermal device for transporting heat from one point to another with quite extraordinary properties. In contrast to single-phased forced convective heat transfer via ‘pumping a fluid’, a thermosyphon (also called a wickless heat pipe) transfers heat through the vaporization/condensing process. The condensate is further returned to the hot source by gravity, i.e., without any requirement of pumps or compressors. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. Two-phase heat transfer by a thermosyphon has the advantage of high enthalpy transport that includes the sensible heat of the liquid, the latent heat of vaporization, and vapor superheat. In contrast, single-phase forced convection transports only the sensible heat of the fluid. Additionally, vapor-phase velocities within a thermosyphon are much greater than single-phase liquid velocities within a forced convective loop. Thermosyphon performance can be limited by the sonic limit (choking) of vapor flow and/or by condensate entrainment. Proper thermosyphon requires analysis of both.

  13. Effects of Drug Abuse

    MedlinePLUS

    ... What To Say if You Were Once Addicted Drug Abuse Prevention Phone Numbers and Websites Search Share You are here Home » Effects of Drugs Effects of Drug Abuse Listen Drug abuse hurts the people who take ...

  14. Excited State Effective Masses

    SciTech Connect

    Lin, Huey-Wen; Cohen, Saul; Fleming, George

    2007-11-01

    The effective mass description of Euclidean time hadron correlation functions is extended to incorporate multiple excited states and multiple correlation functions. In general, the effective masses will be determined by finding the roots of some polynomial.

  15. Medications and Side Effects

    MedlinePLUS

    ... to fully work. You might feel some side effects of your medication before your feel the benefits – ... as sleepiness, anxiety or headache) is a side effect or a symptom of your illness. Many side ...

  16. Side Effects (Management)

    MedlinePLUS

    ... cancer care is relieving side effects, called symptom management, palliative care, or supportive care. It is important ... treat them. To learn about the symptoms and management of the long-term side effects of cancer ...

  17. The Hydrophobic Effect.

    ERIC Educational Resources Information Center

    Huque, Entazul M.

    1989-01-01

    Discusses the physical basis and current understanding of hydrophobic effects. The thermodynamic background of the effects, hydrophobic hydration, and hydrophobic interactions are described. Four existing controversies are outlined. (YP)

  18. Stormwater BMP Effectiveness Toolkit

    EPA Science Inventory

    US EPA has identified the effectiveness of Stormwater Best Management Practices (BMPs) as a priority research need. Effective protection of biotic integrity requires that processes maintaining the diversity of physical habitats be protected. Methods are needed to evaluate the e...

  19. Effective College Teaching.

    ERIC Educational Resources Information Center

    Caraway, James E.

    1978-01-01

    The author discusses other writings on effective college teaching and then presents his list of necessary characteristics for the effective teacher, stressing the interpersonal dimension of the teaching-learning situation. (MF)

  20. Memory effects in turbulence

    NASA Technical Reports Server (NTRS)

    Hinze, J. O.

    1979-01-01

    Experimental investigations of the wake flow of a hemisphere and cylinder show that such memory effects can be substantial and have a significant influence on momentum transport. Memory effects are described in terms of suitable memory functions.

  1. Natural convection heat exchangers for solar water heating systems. Technical progress report, February 1, 1996--March 31, 1996

    SciTech Connect

    Davidson, J.H.

    1998-06-01

    This progress report describes the thermodynamic testing and modeling of a thermosyphon heat exchanger used in solar water heating systems. Testing of a four tube-in-shell thermosyphon heat exchanger was performed in two parts. The first portion of the test increased the collector fluid while the storage tank remained isothermal. After the collector fluid temperature was raised to 95 C, the second part of the test allowed the storage tank to gain heat. The test was performed for two collector flow rates. Measured values included collector side forced flow rate, temperature differences across the heat exchanger, vertical temperature distribution in the storage tank, vertical water temperature profile in the heat exchanger, and pressure drop on the thermosyphon side of the heat exchanger. The overall heat transfer coefficient-area product (UA) values obtained confirmed that models which assume UA depends solely on thermosyphon flow rate do not adequately characterize thermosyphon heat exchangers. This is because heat transfer in thermosyphon exchangers occurs in the mixed convection, rather than forced flow, regime. A linear regression equation was developed to better predict UA using the Prandtl, Reynolds, and Grashof numbers and dimensionless parameters based on fluid properties calculated for the average hot and cold leg temperatures. 9 figs.

  2. Factors hampering program effectiveness.

    PubMed

    Phillips, J F; Zablan, Z C

    1976-01-01

    Findings of the University of the Philippines evaluation research of family planning programs in the Philippines identify 4 major problems which limit effectiveness: 1) acceptance is leveling off; 2) greater proportions of acceptors are choosing the less effective methods; 3) women who switch methods tend to choose a less effective method than the first used and 4) continuation rates for the effective methods are declining. The authors suggest causes and possible remedies for the problems. PMID:12307748

  3. Effects of Nuclear Weapons.

    ERIC Educational Resources Information Center

    Sartori, Leo

    1983-01-01

    Fundamental principles governing nuclear explosions and their effects are discussed, including three components of a nuclear explosion (thermal radiation, shock wave, nuclear radiation). Describes how effects of these components depend on the weapon's yield, its height of burst, and distance of detonation point. Includes effects of three…

  4. Special Effects Activity Guide.

    ERIC Educational Resources Information Center

    Boxer, Jennifer; Valenta, Carol

    This guide accompanies "Special Effects," a 40-minute IMAX film and "Special Effects II", a multimedia, interactive traveling exhibit designed by the California Museum of Science and Industry. The exhibit focuses on the underlying scientific and technical processes of special effects from the earliest motion picture to state-of-the-art digital…

  5. Effects of Nuclear Weapons.

    ERIC Educational Resources Information Center

    Sartori, Leo

    1983-01-01

    Fundamental principles governing nuclear explosions and their effects are discussed, including three components of a nuclear explosion (thermal radiation, shock wave, nuclear radiation). Describes how effects of these components depend on the weapon's yield, its height of burst, and distance of detonation point. Includes effects of three…

  6. Nonlinear Talbot effect.

    PubMed

    Zhang, Yong; Wen, Jianming; Zhu, S N; Xiao, Min

    2010-05-01

    We propose and experimentally demonstrate the nonlinear Talbot effect from nonlinear photonic crystals. The nonlinear Talbot effect results from self-imaging of the generated periodic intensity pattern at the output surface of the crystal. To illustrate the effect, we experimentally observed second-harmonic Talbot self-imaging from 1D and 2D periodically poled LiTaO(3) crystals. Both integer and fractional nonlinear Talbot effects were investigated. The observation not only conceptually extends the conventional Talbot effect, but also opens the door for a variety of new applications in imaging technologies. PMID:20482176

  7. Running effective meetings, running effective groups.

    PubMed

    Ogborn, S E

    1994-12-01

    Meetings are effective if they meet the objectives of each person involved in the least amount of time possible. Different strategies are needed for different types of meetings. Different leadership styles are necessary depending on the members' personality preferences and the stages of the group's development. Good leaders know how to adapt to these preferences and stages. PMID:10139146

  8. Effective Internships for Effective New Administrators.

    ERIC Educational Resources Information Center

    Edmonson, Stacey

    One challenge faced by any educational leadership program is how to develop effective entry-level school administrators. Many administrative interns receive no real administrative practice at all through their internship, and yet upon completion of the internship, they are expected to be competent administrators. The internship at Sam Houston…

  9. Enhanced magnetocaloric effect material

    DOEpatents

    Lewis, Laura J. H.

    2006-07-18

    A magnetocaloric effect heterostructure having a core layer of a magnetostructural material with a giant magnetocaloric effect having a magnetic transition temperature equal to or greater than 150 K, and a constricting material layer coated on at least one surface of the magnetocaloric material core layer. The constricting material layer may enhance the magnetocaloric effect by restriction of volume changes of the core layer during application of a magnetic field to the heterostructure. A magnetocaloric effect heterostructure powder comprising a plurality of core particles of a magnetostructural material with a giant magnetocaloric effect having a magnetic transition temperature equal to or greater than 150 K, wherein each of the core particles is encapsulated within a coating of a constricting material is also disclosed. A method for enhancing the magnetocaloric effect within a giant magnetocaloric material including the step of coating a surface of the magnetocaloric material with a constricting material is disclosed.

  10. Photon Thermal Hall Effect

    NASA Astrophysics Data System (ADS)

    Ben-Abdallah, P.

    2016-02-01

    A near-field thermal Hall effect (i.e., Righi-Leduc effect) in networks of magneto-optical particles placed in a constant magnetic field is predicted. This many-body effect is related to a symmetry breaking in the system induced by the magnetic field, which gives rise to preferential channels for the heat transport by near-field interaction thanks to the particle's anisotropy tuning.

  11. Atomic lighthouse effect

    NASA Astrophysics Data System (ADS)

    Máximo, C. E.; Kaiser, R.; Courteille, Ph. W.; Bachelard, R.

    2014-11-01

    We investigate the deflection of light by a cold atomic cloud when the light-matter interaction is locally tuned via the Zeeman effect using magnetic field gradients. This "lighthouse" effect is strongest in the single-scattering regime, where deviation of the incident field is largest. For optically dense samples, the deviation is reduced by collective effects, as the increase in linewidth leads to a decrease of the magnetic field efficiency.

  12. Dynamic ground effects

    NASA Technical Reports Server (NTRS)

    Paulson, John W., Jr.; Kemmerly, Guy T.; Gilbert, William P.

    1990-01-01

    A research program is underway at the NASA Langley Research Center to study the effect of rate of descent on ground effects. A series of powered models were tested in the Vortex Research Facility under conditions with rate of descent and in the 14 x 22 Foot Subsonic Tunnel under identical conditions but without rate of descent. These results indicate that the rate of descent can have a significant impact on ground effects particularly if vectored or reversed thrust is used.

  13. Atomic lighthouse effect.

    PubMed

    Máximo, C E; Kaiser, R; Courteille, Ph W; Bachelard, R

    2014-11-01

    We investigate the deflection of light by a cold atomic cloud when the light-matter interaction is locally tuned via the Zeeman effect using magnetic field gradients. This "lighthouse" effect is strongest in the single-scattering regime, where deviation of the incident field is largest. For optically dense samples, the deviation is reduced by collective effects, as the increase in linewidth leads to a decrease in magnetic field efficiency. PMID:25401364

  14. Magnetic Casimir effect

    SciTech Connect

    Metalidis, G.; Bruno, P.

    2002-12-01

    The Casimir effect results from alterations of the zero-point electromagnetic energy introduced by boundary conditions. For ferromagnetic layers separated by vacuum (or a dielectric), such boundary conditions are influenced by the magneto-optical Kerr effect. We will show that this gives rise to a long-range magnetic interaction and discuss the effect for two different configurations (magnetization parallel and perpendicular to the layers). Analytical expressions are derived for two models and compared to numerical calculations. Numerical calculations of the effect for Fe are also presented and the possibility of an experimental observation of the Casimir magnetic interaction is discussed.

  15. Rectenna related atmospheric effects

    NASA Technical Reports Server (NTRS)

    Lee, J.

    1980-01-01

    Possible meteorological effects arising from the existence and operations of a solar power satellite (SPS) system rectenna are examined. Analysis and model simulations in some chosen site situations and meteorological conditions indicate that the meteorological effects of the construction and operation of a rectenna are small, particularly outside the boundary of the structure. From weather and climate points of view, installation of an SPS rectenna seems likely to have effects comparable with those due to other nonindustrial land use changes covering the same area. The absorption and scattering of microwave radiation in the troposphere would have negligible atmospheric effects.

  16. Effective medication management.

    PubMed

    Howland, Robert H

    2012-03-01

    The effectiveness of a drug treatment is based on its efficacy, tolerability, safety, and acceptability. Effective medication management implies that the process of selecting and managing prescribed drugs results in an optimal patient outcome. Effectively prescribing medications includes gaining a mastery of drug knowledge, learning the nuts and bolts of treatment using medication, and appreciating the fundamental importance of psychotherapeutic and psychoeducational processes in medication management. Nurses have an essential role in providing effective medication management, given their direct level of patient contact and their collaborative relationship with physicians. PMID:22329622

  17. Volcanic effects on climate

    NASA Technical Reports Server (NTRS)

    Robock, Alan

    1991-01-01

    Volcanic eruptions which inject large amounts of sulfur-rich gas into the stratosphere produce dust veils which last years and cool the earth's surface. At the same time, these dust veils absorb enough solar radiation to warm the stratosphere. Since these temperature changes at the earth's surface and in the stratosphere are both in the opposite direction of hypothesized effects from greenhouse gases, they act to delay and mask the detection of greenhouse effects on the climate system. Tantalizing recent research results have suggested regional effects of volcanic eruptions, including effects on El Nino/Southern Oscillation (ENSO). In addition, a large portion of the global climate change of the past 100 years may be due to the effects of volcanoes, but a definite answer is not yet clear. While effects of several years were demonstrated with both data studies and numerical models, long-term effects, while found in climate model calculations, await confirmation with more realistic models. Extremely large explosive prehistoric eruptions may have produced severe weather and climate effects, sometimes called a 'volcanic winter'. Complete understanding of the above effects of volcanoes is hampered by inadequacies of data sets on volcanic dust veils and on climate change. Space observations can play an increasingly important role in an observing program in the future. The effects of volcanoes are not adequately separated from ENSO events, and climate modeling of the effects of volcanoes is in its infancy. Specific suggestions are made for future work to improve the knowledge of this important component of the climate system.

  18. Institutional Effectiveness Report.

    ERIC Educational Resources Information Center

    College of the Canyons, Santa Clarita, CA.

    This is the first edition of the College of the Canyon's (California) Institutional Effectiveness Report, which is modeled after the statewide report prepared by the Chancellor's Office. The college is measuring 60 effectiveness indicators in four mission areas: student access, student success, staff composition, and fiscal condition. A brief…

  19. Effects on Insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of controlled and modified atmospheres on insects is reviewed and summarized in this chapter. Traditionally, controlled and modified atmospheres are used to store and preserve fresh fruits and vegetables. The effects on insects and the potential of these treatments are secondary to the...

  20. The Pygmalion Effect Lives

    ERIC Educational Resources Information Center

    Rosenthal, Robert

    1973-01-01

    Briefly reviewing his own research, and that of critics of the Pygmalion Effect, the author proposes a four-factor "theory" of the influences that produce the effect: the relationship of teachers to special students differs in climate, input, feedback, and output. (JM)

  1. Presenting Food Science Effectively

    ERIC Educational Resources Information Center

    Winter, Carl K.

    2016-01-01

    While the need to present food science information effectively is viewed as a critical competency for food scientists by the Institute of Food Technologists, most food scientists may not receive adequate training in this area. Effective presentations combine both scientific content and delivery mechanisms that demonstrate presenter enthusiasm for…

  2. The Kaye Effect

    ERIC Educational Resources Information Center

    Binder, J. M.; Landig, A. J.

    2009-01-01

    The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for secondary school students. This is our solution to problem number 10, "The Kaye effect", as presented in the final round of the 21st IYPT in Trogir, Croatia. The Kaye effect occurs when a thin stream of shampoo or a different adequate non-Newtonian liquid…

  3. Effective Appraisal Systems.

    ERIC Educational Resources Information Center

    Winsor, Jerry L.

    An examination of the goals of an effective employee appraisal system of an effective employee evaluation procedure is the focus of this paper.The paper discusses the purposes of the appraisal system and its objectivity (or lack of it), the selection of items to be judged, the standards for judging the performance of an employee, and the person…

  4. The Chelate Effect Redefined.

    ERIC Educational Resources Information Center

    da Silva, J. J. R. Frausto

    1983-01-01

    Discusses ambiguities of the accepted definition of the chelate effect, suggesting that it be defined in terms of experimental observation rather than mathematical abstraction. Indicates that the effect depends on free energy change in reaction, ligand basicity, pH of medium, type of chelates formed, and concentration of ligands in solution. (JN)

  5. Defining Effective Teaching

    ERIC Educational Resources Information Center

    Layne, L.

    2012-01-01

    The author looks at the meaning of specific terminology commonly used in student surveys: "effective teaching." The research seeks to determine if there is a difference in how "effective teaching" is defined by those taking student surveys and those interpreting the results. To investigate this difference, a sample group of professors and students…

  6. Correlational effect size benchmarks.

    PubMed

    Bosco, Frank A; Aguinis, Herman; Singh, Kulraj; Field, James G; Pierce, Charles A

    2015-03-01

    Effect size information is essential for the scientific enterprise and plays an increasingly central role in the scientific process. We extracted 147,328 correlations and developed a hierarchical taxonomy of variables reported in Journal of Applied Psychology and Personnel Psychology from 1980 to 2010 to produce empirical effect size benchmarks at the omnibus level, for 20 common research domains, and for an even finer grained level of generality. Results indicate that the usual interpretation and classification of effect sizes as small, medium, and large bear almost no resemblance to findings in the field, because distributions of effect sizes exhibit tertile partitions at values approximately one-half to one-third those intuited by Cohen (1988). Our results offer information that can be used for research planning and design purposes, such as producing better informed non-nil hypotheses and estimating statistical power and planning sample size accordingly. We also offer information useful for understanding the relative importance of the effect sizes found in a particular study in relationship to others and which research domains have advanced more or less, given that larger effect sizes indicate a better understanding of a phenomenon. Also, our study offers information about research domains for which the investigation of moderating effects may be more fruitful and provide information that is likely to facilitate the implementation of Bayesian analysis. Finally, our study offers information that practitioners can use to evaluate the relative effectiveness of various types of interventions. PMID:25314367

  7. School Effectiveness and Leadership.

    ERIC Educational Resources Information Center

    Dow, I. I.; Oakley, W. F.

    1992-01-01

    Fiedler's contingency theory relates school effectiveness to a combination of principals' leadership style and situational favorability for the principal. Data from teacher questionnaires on school climate and effectiveness and measures of principal's leadership in 176 Canadian elementary schools did not support Fiedler's model. Contains 54…

  8. JPL Radiation Effects Facilities

    NASA Technical Reports Server (NTRS)

    Thorbourn, Dennis

    2013-01-01

    Radiation Effects Group investigates the effects of space radiation on present and future microelectronic and optoelectronic technologies, evaluate the risk of using them in specific space missions, and recommend component and design techniques for JPL and NASA programs to reduce reliability risk from space radiation.

  9. Tomography with mirage effect

    NASA Astrophysics Data System (ADS)

    Jeanneau, P.; Bertrand, L.; Forget, B. C.; Fournier, D.

    1999-03-01

    We have designed an experimental set-up that allows us to obtain thermal images of small samples by associating the mirage effect with the tomographic techniques. Spectroscopic features, surface effects and thermal diffusivity changes have been used to illustrate the feasibility of the method.

  10. Radiation effects in space

    SciTech Connect

    Fry, R.J.M.

    1987-07-01

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

  11. The Kaye Effect

    ERIC Educational Resources Information Center

    Binder, J. M.; Landig, A. J.

    2009-01-01

    The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for secondary school students. This is our solution to problem number 10, "The Kaye effect", as presented in the final round of the 21st IYPT in Trogir, Croatia. The Kaye effect occurs when a thin stream of shampoo or a different adequate non-Newtonian liquid…

  12. Presenting Food Science Effectively

    ERIC Educational Resources Information Center

    Winter, Carl K.

    2016-01-01

    While the need to present food science information effectively is viewed as a critical competency for food scientists by the Institute of Food Technologists, most food scientists may not receive adequate training in this area. Effective presentations combine both scientific content and delivery mechanisms that demonstrate presenter enthusiasm for…

  13. Primacy Effects in Attributions.

    ERIC Educational Resources Information Center

    McAndrew, Francis T.

    Previous research has suggested the existence of a primacy effect in the attribution of ability. To test if the primacy effect occurs in situations where specific cues about the person and nature of the test materials are lacking or greatly reduced, college students corrected a multiple-choice test in which a phantom stimulus person correctly…

  14. Parent Groups: How Effective?

    ERIC Educational Resources Information Center

    Veltkamp, Lane J.; Newman, Keith

    1976-01-01

    The educational approach in parent groups has not demonstrated itself effective, particularly in dysfunctional families. Parent groups, to be effective, must include, (a) an educational component, (b) a therapeutic component, and (c) an eclectic approach that gives parent specific management techniques but also focuses on the marital and family…

  15. A ''Voice Inversion Effect?''

    ERIC Educational Resources Information Center

    Bedard, Catherine; Belin, Pascal

    2004-01-01

    Voice is the carrier of speech but is also an ''auditory face'' rich in information on the speaker's identity and affective state. Three experiments explored the possibility of a ''voice inversion effect,'' by analogy to the classical ''face inversion effect,'' which could support the hypothesis of a voice-specific module. Experiment 1 consisted…

  16. The polarized EMC effect

    SciTech Connect

    W. Bentz; I. C. Cloet; A. W. Thomas

    2007-02-01

    We calculate both the spin independent and spin dependent nuclear structure functions in an effective quark theory. The nucleon is described as a composite quark-diquark state, and the nucleus is treated in the mean field approximation. We predict a sizable polarized EMC effect, which could be confirmed in future experiments.

  17. Bulk Topological Proximity Effect.

    PubMed

    Hsieh, Timothy H; Ishizuka, Hiroaki; Balents, Leon; Hughes, Taylor L

    2016-02-26

    Existing proximity effects stem from systems with a local order parameter, such as a local magnetic moment or a local superconducting pairing amplitude. Here, we demonstrate that despite lacking a local order parameter, topological phases also may give rise to a proximity effect of a distinctively inverted nature. We focus on a general construction in which a topological phase is extensively coupled to a second system, and we argue that, in many cases, the inverse topological order will be induced on the second system. To support our arguments, we rigorously establish this "bulk topological proximity effect" for all gapped free-fermion topological phases and representative integrable models of interacting topological phases. We present a terrace construction which illustrates the phenomenological consequences of this proximity effect. Finally, we discuss generalizations beyond our framework, including how intrinsic topological order may also exhibit this effect. PMID:26967436

  18. Bulk Topological Proximity Effect

    NASA Astrophysics Data System (ADS)

    Hsieh, Timothy H.; Ishizuka, Hiroaki; Balents, Leon; Hughes, Taylor L.

    2016-02-01

    Existing proximity effects stem from systems with a local order parameter, such as a local magnetic moment or a local superconducting pairing amplitude. Here, we demonstrate that despite lacking a local order parameter, topological phases also may give rise to a proximity effect of a distinctively inverted nature. We focus on a general construction in which a topological phase is extensively coupled to a second system, and we argue that, in many cases, the inverse topological order will be induced on the second system. To support our arguments, we rigorously establish this "bulk topological proximity effect" for all gapped free-fermion topological phases and representative integrable models of interacting topological phases. We present a terrace construction which illustrates the phenomenological consequences of this proximity effect. Finally, we discuss generalizations beyond our framework, including how intrinsic topological order may also exhibit this effect.

  19. Nocebo effect in Dermatology.

    PubMed

    Sonthalia, Sidharth; Sahaya, Kinshuk; Arora, Rahul; Singal, Archana; Srivastava, Ankur; Wadhawan, Ritu; Zartab, Hamed; Gupta, Kripa Shankar

    2015-01-01

    Nocebo effect, originally denoting the negative counterpart of the placebo phenomenon, is now better defined as the occurrence of adverse effects to a therapeutic intervention because the patient expects them to develop. More commonly encountered in patients with a past negative experience, this effect stems from highly active processes in the central nervous system, mediated by specific neurotransmitters and modulated by psychological mechanisms such as expectation and conditioning. The magnitude of nocebo effect in clinical medicine is being increasingly appreciated and its relevance encompasses clinical trials as well as clinical practice. Although there is hardly any reference to the term nocebo in dermatology articles, the phenomenon is encountered routinely by dermatologists. Dermatology patients are more susceptible to nocebo responses owing to the psychological concern from visibility of skin lesions and the chronicity, unpredictable course, lack of 'permanent cure' and frequent relapses of skin disorders. While finasteride remains the prototypical drug that displays a prominent nocebo effect in dermatologic therapeutics, other drugs such as isotretinoin are also likely inducers. This peculiar phenomenon has recently been appreciated in the modulation of itch perception and in controlled drug provocation tests in patients with a history of adverse drug reactions. Considering the conflict between patients' right to information about treatment related adverse effects and the likelihood of nocebo effect stemming from information disclosure, the prospect of ethically minimizing nocebo effect remains daunting. In this article, we review the concept of nocebo effect, its postulated mechanism, relevance in clinical dermatology and techniques to prevent it from becoming a barrier to effective patient management. PMID:25900939

  20. Bustling argon: biological effect

    PubMed Central

    2013-01-01

    Argon is a noble gas in group 18 of the periodic table. Certificated to exist in air atmosphere merely one century ago, discovery of argon shows interesting stories of researching and exploring. It was assumed to have no chemical activity. However, argon indeed present its biological effect on mammals. Narcotic effect of argon in diving operation and neur-protective function of argon in cerebral injury demonstrate that argon has crucial effect and be concentrated on is necessary. Furthermore, consider to be harmless to human, argon clinical application in therapy would be another option. PMID:24088583

  1. Improving engineering effectiveness

    NASA Technical Reports Server (NTRS)

    Fiero, J. D.

    1985-01-01

    Methodologies to improve engineering productivity were investigated. The rocky road to improving engineering effectiveness is reviewed utilizing a specific semiconductor engineering organization as a case study. The organization had a performance problem regarding new product introductions. With the help of this consultant as a change agent the engineering team used a systems approach to through variables that were effecting their output significantly. Critical factors for improving this engineering organization's effectiveness and the roles/responsibilities of management, the individual engineers and the internal consultant are discussed.

  2. BSM Primary effects

    NASA Astrophysics Data System (ADS)

    Gupta, R.

    Using the predictive power of the effective field theory approach, we present a physical parametrization of the leading effects beyond the SM (BSM), that give us at present the best way to constrain heavy new-physics at low-energies. We show that other BSM effects are not independent from these ones, and we provide the explicit correlations. This information is useful to know where to primarily look for new physics in future experiments, and to know how this new physics is related to previous measurements, most importantly in electroweak-symmetry breaking processes or Higgs physics.

  3. Effects of New Technologies.

    ERIC Educational Resources Information Center

    Social and Labour Bulletin, 1980

    1980-01-01

    Transnational implications of technological change and innovation in telecommunications are discussed, including impact on jobs and industrial relations, computer security, access to information, and effects of technological innovation on international economic systems. (SK)

  4. Radiation effects in space

    SciTech Connect

    Fry, R.J.M.

    1986-01-01

    The paper discusses the radiation environment in space that astronauts are likely to be exposed to. Emphasis is on proton and HZE particle effects. Recommendations for radiation protection guidelines are presented. (ACR)

  5. Pulmonary effects of firefighting.

    PubMed

    Scannell, C H; Balmes, J R

    1995-01-01

    The authors examine the acute and chronic effects of exposure to smoke among firefighters and look at mortality studies for the risk of death due to nonmalignant respiratory disease and lung cancer. PMID:8903749

  6. [Aminoglycosides, their ototoxic effect].

    PubMed

    de la Rosa-Gálvez, A; Jáuregui-Renaud, K; Hernández-Goribar, M

    1998-01-01

    The aminoglycosides are broad-spectrum antibiotics especially effective against many strains of gramnegative bacteria. Since streptomycin was used for tuberculosis treatment, the toxic side effects of such antibiotics were identified. The kidney and the inner ear are affected. The nephrotoxicity is usually reversible, while the chronic ototoxicity is irreversible. Within the inner ear, it is the cochlear and vestibular sensory epithelium that is damaged. A toxic mechanism in which an interference with mitochondrial protein synthesis is central has been inferred. During the last fifty years, risk factors for aminoglycoside-induced-ototoxicity have been identified, including a genetically transmitted hypersensitivity to the ototoxic effect. Although several strategies to prevent the damage have been proposed, today it is not rare that patients suffer permanent loss of hearing and loss of balance due to aminoglycoside toxicity. This review gives a brief background of aminoglycoside ototoxicity, some strategies to prevent it, and the therapeutic use of the vestibulo-toxic effect. PMID:9927776

  7. Cytogenetic effects of cyclamates

    SciTech Connect

    Jemison, E.W.; Brown, K.; Rivers, B.; Knight, R.

    1984-01-01

    PHA-stimulated human peripheral lymphocytes were used as a model system for assessing the in vitro effects of calcium cyclamate. Techniques of autoradiography, cytological staining, cell counting, liquid scintillation and karyotyping were used to study the cytogenetic damage and biochemical effects of calcium cyclamate when assayed in 24 hour intervals for 96 hours. The cells were exposed to 10(-2) and 10(-3) molar concentrations of calcium cyclamate in TC 199 medium with fetal calf serum and antibiotics. It was noted that the addition of cyclamate increased mitotic rate of lymphocyte cells in cultures. It was determined that calcium cyclamate impaired the synthesis of deoxribonunucleic acid (as depicted by decreased incorporation of tritiated thymidine), reduced grain counts in autoradiographs and increased chromosome aberrations in cyclamate treated PHA stimulated peripheral blood lymphocytes in vitro. Morphological changes and growth rates showed significant effects. These studies indicate that calcium cyclamate has variable significant effects on leucocytes growth and chromosome morphology.

  8. Comparative effectiveness research.

    PubMed

    Hirsch, J A; Schaefer, P W; Romero, J M; Rabinov, J D; Sanelli, P C; Manchikanti, L

    2014-09-01

    The goal of comparative effectiveness research is to improve health care while dealing with the seemingly ever-rising cost. An understanding of comparative effectiveness research as a core topic is important for neuroradiologists. It can be used in a variety of ways. Its goal is to look at alternative methods of interacting with a clinical condition, ideally, while improving delivery of care. While the Patient-Centered Outcome Research initiative is the most mature US-based foray into comparative effectiveness research, it has been used more robustly in decision-making in other countries for quite some time. The National Institute for Health and Clinical Excellence of the United Kingdom is a noteworthy example of comparative effectiveness research in action. PMID:24874531

  9. [Genetic effects of radiation].

    PubMed

    Nakamura, Nori

    2012-03-01

    This paper is a short review of genetic effect of radiation. This includes methods and results of a large-scale genetic study on specific loci in mice and of various studies in the offspring of atomic-bomb survivors. As for the latter, there is no results obtained which suggest the effect of parental exposure to radiation. Further, in recent years, studies are conducted to the offspring born to parents who were survivors of childhood cancers. In several reports, the mean gonad dose is quite large whereas in most instances, the results do not indicate genetic effect following parental exposure to radiation. Possible reasons for the difficulties in detecting genetic effect of radiation are discussed. PMID:22514926

  10. Strategies for Effective Outsourcing.

    ERIC Educational Resources Information Center

    Moneta, Larry; Dillon, William L.

    2001-01-01

    Emphasizes strategies that can be employed for effective outsourcing in higher education settings. Several models of outsourcing are identified and described, and examples of institutions using each model are provided. (GCP)

  11. Cardiovascular Effects of Weightlessness

    NASA Technical Reports Server (NTRS)

    Short, K.

    1985-01-01

    Physiological changes resulting from long term weightlessness are reviewed and activities conducted to study cardiovascular deconditioning at NASA Ames are discussed. Emphasis is on using monkeys in chair rest, water immersion, and tilt table studies to simulate space environment effects.

  12. Coefficients of Effective Length.

    ERIC Educational Resources Information Center

    Edwards, Roger H.

    1981-01-01

    Under certain conditions, a validity Coefficient of Effective Length (CEL) can produce highly misleading results. A modified coefficent is suggested for use when empirical studies indicate that underlying assumptions have been violated. (Author/BW)

  13. Systems effectiveness evaluation program

    NASA Technical Reports Server (NTRS)

    Nicely, H. P., Jr.; Givens, W. D.

    1972-01-01

    Eight integrated computer programs provide needed capability to reduce man-hours needed to perform routine monitoring and assessment of effectiveness, reliability, and maintainability of large electronic equipment systems.

  14. Diuretic Effects of Cannabinoids

    PubMed Central

    Thakur, Ganesh A.; Bajaj, Shama; Nikas, Spyros P.; Vemuri, V. Kiran; Makriyannis, Alexandros; Bergman, Jack

    2013-01-01

    In vivo effects of cannabinoid (CB) agonists are often assessed using four well-established measures: locomotor activity, hypothermia, cataleptic-like effects, and analgesia. The present studies demonstrate that doses of CB agonists that produce these effects also reliably increase diuresis. Diuretic effects of several CB agonists were measured in female rats over 2 hours immediately after drug injection, and results were compared with hypothermic effects. Direct-acting CB1 agonists, including ?9-tetrahydrocannabinol, WIN 55,212 [R-(1)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl)methanone mesylate], AM2389 [9?-hydroxy-3-(1-hexyl-cyclobut-1-yl)-hexahydrocannabinol], and AM4054 [9?-(hydroxymethyl)-3-(1-adamantyl)-hexahydrocannabinol], produced dose-dependent increases in diuresis and decreases in colonic temperature, with slightly lower ED50 values for diuresis than for hypothermia. The highest doses of cannabinoid drugs yielded, on average, 26–32 g/kg urine; comparable effects were obtained with 10 mg/kg furosemide and 3.0 mg/kg trans-(-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]benzeneacetamide (U50-488). Methanandamide (10.0 mg/kg) had lesser effect than other CB agonists, and the CB2 agonist AM1241 [1-(methylpiperidin-2-ylmethyl)-3-(2-iodo-5-nitrobenzoyl)indole], the anandamide transport inhibitor AM404, and the CB antagonist rimonabant did not have diuretic effects. In further studies, the diuretic effects of the CB1 agonist AM4054 were similar in male and female rats, displayed a relatively rapid onset to action, and were dose-dependently antagonized by 30 minutes pretreatment with rimonabant, but not by the vanilloid receptor type I antagonist capsazepine, nor were the effects of WIN 55,212 antagonized by the CB2 antagonist AM630 [(6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl](4-methoxyphenyl) methanone)]. These data indicate that cannabinoids have robust diuretic effects in rats that are mediated via CB1 receptor mechanisms. PMID:23019138

  15. The extraterrestrial Casimir Effect

    NASA Astrophysics Data System (ADS)

    Storti, Riccardo C.

    2011-09-01

    Application of the Electro-Gravi-Magnetic (EGM) Photon radiation method to the Casimir Effect (CE), suggests that the experimentally verified (terrestrially) neutrally charged Parallel-Plate configuration force, may differ within extraterrestrial gravitational environments from the gravitationally independent formulation by Casimir. Consequently, the derivation presented herein implies that a gravitationally dependent CE may become an important design factor in nanotechnology for extraterrestrial applications (ignoring finite conductivity + temperature effects and evading the requirement for Casimir Force corrections due to surface roughness).

  16. Centrifugal effects in Skyrmeons

    SciTech Connect

    Braaten, E.

    1984-01-01

    We give a qualitative discussion of centrifugal effects in the Skyrme model and methods for treating these effects. We show that there may be states in the spectrum which would not appear in a semiclassical expansion about the static soliton solution. We consider semiclassical expansions about static solutions and about uniformly-rotating solutions, and discuss the validity and limitations of both approaches. 11 references.

  17. Secondary pool boiling effects

    NASA Astrophysics Data System (ADS)

    Kruse, C.; Tsubaki, A.; Zuhlke, C.; Anderson, T.; Alexander, D.; Gogos, G.; Ndao, S.

    2016-02-01

    A pool boiling phenomenon referred to as secondary boiling effects is discussed. Based on the experimental trends, a mechanism is proposed that identifies the parameters that lead to this phenomenon. Secondary boiling effects refer to a distinct decrease in the wall superheat temperature near the critical heat flux due to a significant increase in the heat transfer coefficient. Recent pool boiling heat transfer experiments using femtosecond laser processed Inconel, stainless steel, and copper multiscale surfaces consistently displayed secondary boiling effects, which were found to be a result of both temperature drop along the microstructures and nucleation characteristic length scales. The temperature drop is a function of microstructure height and thermal conductivity. An increased microstructure height and a decreased thermal conductivity result in a significant temperature drop along the microstructures. This temperature drop becomes more pronounced at higher heat fluxes and along with the right nucleation characteristic length scales results in a change of the boiling dynamics. Nucleation spreads from the bottom of the microstructure valleys to the top of the microstructures, resulting in a decreased surface superheat with an increasing heat flux. This decrease in the wall superheat at higher heat fluxes is reflected by a "hook back" of the traditional boiling curve and is thus referred to as secondary boiling effects. In addition, a boiling hysteresis during increasing and decreasing heat flux develops due to the secondary boiling effects. This hysteresis further validates the existence of secondary boiling effects.

  18. Spin Hall effects

    NASA Astrophysics Data System (ADS)

    Sinova, Jairo; Valenzuela, Sergio O.; Wunderlich, J.; Back, C. H.; Jungwirth, T.

    2015-10-01

    Spin Hall effects are a collection of relativistic spin-orbit coupling phenomena in which electrical currents can generate transverse spin currents and vice versa. Despite being observed only a decade ago, these effects are already ubiquitous within spintronics, as standard spin-current generators and detectors. Here the theoretical and experimental results that have established this subfield of spintronics are reviewed. The focus is on the results that have converged to give us the current understanding of the phenomena, which has evolved from a qualitative to a more quantitative measurement of spin currents and their associated spin accumulation. Within the experimental framework, optical-, transport-, and magnetization-dynamics-based measurements are reviewed and linked to both phenomenological and microscopic theories of the effect. Within the theoretical framework, the basic mechanisms in both the extrinsic and intrinsic regimes are reviewed, which are linked to the mechanisms present in their closely related phenomenon in ferromagnets, the anomalous Hall effect. Also reviewed is the connection to the phenomenological treatment based on spin-diffusion equations applicable to certain regimes, as well as the spin-pumping theory of spin generation used in many measurements of the spin Hall angle. A further connection to the spin-current-generating spin Hall effect to the inverse spin galvanic effect is given, in which an electrical current induces a nonequilibrium spin polarization. This effect often accompanies the spin Hall effect since they share common microscopic origins. Both can exhibit the same symmetries when present in structures comprising ferromagnetic and nonmagnetic layers through their induced current-driven spin torques or induced voltages. Although a short chronological overview of the evolution of the spin Hall effect field and the resolution of some early controversies is given, the main body of this review is structured from a pedagogical point of view, focusing on well-established and accepted physics. In such a young field, there remains much to be understood and explored, hence some of the future challenges and opportunities of this rapidly evolving area of spintronics are outlined.

  19. Barriers to effective teaching.

    PubMed

    DaRosa, Debra A; Skeff, Kelley; Friedland, Joan A; Coburn, Michael; Cox, Susan; Pollart, Susan; O'connell, Mark; Smith, Sandy

    2011-04-01

    Medical school faculty members are charged with the critical responsibility of preparing the future physician and medical scientist workforce. Recent reports suggest that medical school curricula have not kept pace with societal needs and that medical schools are graduating students who lack the knowledge and skills needed to practice effectively in the 21st century. The majority of faculty members want to be effective teachers and graduate well-prepared medical students, but multiple and complex factors-curricular, cultural, environmental, and financial-impede their efforts. Curricular impediments to effective teaching include unclear definitions of and disagreement on learning needs, misunderstood or unstated goals and objectives, and curriculum sequencing challenges. Student and faculty attitudes, too few faculty development opportunities, and the lack of an award system for teaching all are major culture-based barriers. Environmental barriers, such as time limitations, the setting, and the physical space in which medical education takes place, and financial barriers, such as limited education budgets, also pose serious challenges to even the most committed teachers. This article delineates the barriers to effective teaching as noted in the literature and recommends action items, some of which are incremental whereas others represent major change. Physicians-in-training, medical faculty, and society are depending on medical education leaders to address these barriers to effect the changes needed to enhance teaching and learning. PMID:21346500

  20. Temperature effects on electrophoresis.

    PubMed

    Rogacs, Anita; Santiago, Juan G

    2013-05-21

    We present a model capturing the important contributors to the effects of temperature on the observable electrophoretic mobilities of small ions, and on solution conductivity and pH. Our temperature model includes relations for temperature-dependent viscosity, ionic strength corrections, degree of ionization (pK), and ion solvation effects on mobility. We incorporate thermophysical data for water viscosity, temperature-dependence of the Onsager-Fuoss model for finite ionic strength effects on mobility, temperature-dependence of the extended Debye-Huckel theory for correction of ionic activity, the Clarke-Glew approach and tabulated thermodynamic quantities of ionization reaction for acid dissociation constants as a function of temperature, and species-specific, empirically evaluated correction terms for temperature-dependence of Stokes' radii. We incorporated our model into a MATLAB-based simulation tool we named Simulation of Temperature Effects on ElectroPhoresis (STEEP). We validated our model using conductivity and pH measurements across a temperature variation of 25-70 °C for a set of electrolytes routinely used in electrophoresis. The model accurately captures electrolyte solution pH and conductivity, including important effects not captured by simple Walden-type relations. PMID:23627294

  1. Pleiotropic effects of statins.

    PubMed

    Kavalipati, Narasaraju; Shah, Jay; Ramakrishan, Ananthraman; Vasnawala, Hardik

    2015-01-01

    Statins or 3-hydroxy-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors not only prevents the synthesis of cholesterol biosynthesis but also inhibits the synthesis of essential isoprenoid intermediates such as farnesyl pyrophosphate, geranylgeranyl pyrophosphate, isopentanyl adenosine, dolichols and polyisoprenoid side chains of ubiquinone, heme A, and nuclear lamins. These isoprenoid intermediates are required for activation of various intracellular/signaling proteins- small guanosine triphosphate bound protein Ras and Ras-like proteins like Rho, Rab, Rac, Ral, or Rap which plays an indispensible role in multiple cellular processes. Reduction of circulating isoprenoids intermediates as a result of HMG CoA reductase inhibition by statins prevents activation of these signalling proteins. Hence, the multiple effects of statins such as antiinflammatory effects, antioxidant effects, antiproliferative and immunomodulatory effects, plaque stability, normalization of sympathetic outflow, and prevention of platelet aggregation are due to reduction of circulating isoprenoids and hence inactivation of signalling proteins. These multiple lipid-independent effects of statins termed as statin pleiotropy would potentially open floodgates for research in multiple treatment domains catching attentions of researchers and clinician across the globe. PMID:26425463

  2. The real butterfly effect

    NASA Astrophysics Data System (ADS)

    Palmer, T. N.; Döring, A.; Seregin, G.

    2014-09-01

    Historical evidence is reviewed to show that what Ed Lorenz meant by the iconic phrase ‘the butterfly effect’ is not at all captured by the notion of sensitive dependence on initial conditions in low-order chaos. Rather, as presented in his 1969 Tellus paper, Lorenz intended the phrase to describe the existence of an absolute finite-time predicability barrier in certain multi-scale fluid systems, implying a breakdown of continuous dependence on initial conditions for large enough forecast lead times. To distinguish from ‘mere’ sensitive dependence, the effect discussed in Lorenz's Tellus paper is referred to as ‘the real butterfly effect’. Theoretical evidence for such a predictability barrier in a fluid described by the three-dimensional Navier-Stokes equations is discussed. Whilst it is still an open question whether the Navier-Stokes equation has this property, evidence from both idealized atmospheric simulators and analysis of operational weather forecasts suggests that the real butterfly effect exists in an asymptotic sense, i.e. for initial-time atmospheric perturbations that are small in scale and amplitude compared with (weather) scales of interest, but still large in scale and amplitude compared with variability in the viscous subrange. Despite this, the real butterfly effect is an intermittent phenomenon in the atmosphere, and its presence can be signalled a priori, and hence mitigated, by ensemble forecast methods.

  3. Attributing effects to interactions

    PubMed Central

    VanderWeele, Tyler J.; Tchetgen Tchetgen, Eric J.

    2014-01-01

    A framework is presented that allows an investigator to estimate the portion of the effect of one exposure that is attributable to an interaction with a second exposure. We show that when the two exposures are independent, the total effect of one exposure can be decomposed into a conditional effect of that exposure and a component due to interaction. The decomposition applies on difference or ratio scales. We discuss how the components can be estimated using standard regression models, and how these components can be used to evaluate the proportion of the total effect of the primary exposure attributable to the interaction with the second exposure. In the setting in which one of the exposures affects the other, so that the two are no longer independent, alternative decompositions are discussed. The various decompositions are illustrated with an example in genetic epidemiology. If it is not possible to intervene on the primary exposure of interest, the methods described in this paper can help investigators to identify other variables that, if intervened upon, would eliminate the largest proportion of the effect of the primary exposure. PMID:25051310

  4. Aviation noise effects

    NASA Astrophysics Data System (ADS)

    Newman, J. S.; Beattie, K. R.

    1985-03-01

    This report summarizes the effects of aviation noise in many areas, ranging from human annoyance to impact on real estate values. It also synthesizes the findings of literature on several topics. Included in the literature were many original studies carried out under FAA and other Federal funding over the past two decades. Efforts have been made to present the critical findings and conclusions of pertinent research, providing, when possible, a bottom line conclusion, criterion or perspective. Issues related to aviation noise are highlighted, and current policy is presented. Specific topic addressed include: annoyance; Hearing and hearing loss; noise metrics; human response to noise; speech interference; sleep interference; non-auditory health effects of noise; effects of noise on wild and domesticated animals; low frequency acoustical energy; impulsive noise; time of day weightings; noise contours; land use compatibility; and real estate values. This document is designed for a variety of users, from the individual completely unfamiliar with aviation noise to experts in the field.

  5. Effective Documentation Tools

    NASA Technical Reports Server (NTRS)

    Sleboda, Claire

    1997-01-01

    Quality assurance programs provide a very effective means to monitor and evaluate medical care. Quality assurance involves: (1) Identify a problem; (2) Determine the source and nature of the problem; (3) Develop policies and methods to effect improvement; (4) Implement those polices; (5) Monitor the methods applied; and (6) Evaluate their effectiveness. Because this definition of quality assurance so closely resembles the Nursing Process, the health unit staff was able to use their knowledge of the nursing process to develop many forms which improve the quality of patient care. These forms include the NASA DFRC Service Report, the occupational injury form (Incident Report), the patient survey (Pre-hospital Evaluation/Care Report), the Laboratory Log Sheet, the 911 Run Sheet, and the Patient Assessment Stamp. Examples and steps which are followed to generate these reports are described.

  6. The ``Cheerios effect''

    NASA Astrophysics Data System (ADS)

    Vella, Dominic; Mahadevan, L.

    2005-09-01

    Objects that float at the interface between a liquid and a gas interact because of interfacial deformation and the effect of gravity. We highlight the crucial role of buoyancy in this interaction, which, for small particles, prevails over the capillary suction that often is assumed to be the dominant effect. We emphasize this point using a simple classroom demonstration, and then derive the physical conditions leading to mutual attraction or repulsion. We also quantify the force of interaction in particular instances and present a simple dynamical model of this interaction. The results obtained from this model are validated by comparison to experimental results for the mutual attraction of two identical spherical particles. We consider some of the applications of the effect that can be found in nature and the laboratory.

  7. Security effectiveness review (SER)

    SciTech Connect

    Kouprianova, I.; Ek, D.; Showalter, R.; Bergman, M.

    1998-08-01

    As part of the on-going DOE/Russian MPC and A activities at the Institute of Physics and Power Engineering (IPPE) and in order to provide a basis for planning MPC and A enhancements, an expedient method to review the effectiveness of the MPC and A system has been adopted. These reviews involve the identification of appropriate and cost-effective enhancements of facilities at IPPE. This effort requires a process that is thorough but far less intensive than a traditional vulnerability assessment. The SER results in a quick assessment of current and needed enhancements. The process requires preparation and coordination between US and Russian analysts before, during, and after information gathering at the facilities in order that the analysis is accurate, effective, and mutually agreeable. The goal of this paper is to discuss the SER process, including the objectives, time scale, and lessons learned at IPPE.

  8. Disentangling the EMC effect

    NASA Astrophysics Data System (ADS)

    Piasetzky, E.; Hen, O.; Weinstein, L. B.

    2013-10-01

    The deep inelastic scattering cross section for scattering from bound nucleons differs from that of free nucleons. This phenomena, first discovered 30 years ago, is known as the EMC effect and is still not fully understood. Recent analysis of world data showed that the strength of the EMC effect is linearly correlated with the relative amount of Two-Nucleon Short Range Correlated pairs (2N-SRC) in nuclei. The latter are pairs of nucleons whose wave functions overlap, giving them large relative momentum and low center of mass momentum, where high and low is relative to the Fermi momentum of the nucleus. The observed correlation indicates that the EMC effect, like 2N-SRC pairs, is related to high momentum nucleons in the nucleus. This paper reviews previous studies of the EMC-SRC correlation and studies its robustness. It also presents a planned experiment aimed at studying the origin of this EMC-SRC correlation.

  9. Effective Nutritional Supplement Combinations

    NASA Astrophysics Data System (ADS)

    Cooke, Matt; Cribb, Paul J.

    Few supplement combinations that are marketed to athletes are supported by scientific evidence of their effectiveness. Quite often, under the rigor of scientific investigation, the patented combination fails to provide any greater benefit than a group given the active (generic) ingredient. The focus of this chapter is supplement combinations and dosing strategies that are effective at promoting an acute physiological response that may improve/enhance exercise performance or influence chronic adaptations desired from training. In recent years, there has been a particular focus on two nutritional ergogenic aids—creatine monohydrate and protein/amino acids—in combination with specific nutrients in an effort to augment or add to their already established independent ergogenic effects. These combinations and others are discussed in this chapter.

  10. Paramagnetic spin seebeck effect.

    PubMed

    Wu, Stephen M; Pearson, John E; Bhattacharya, Anand

    2015-05-01

    We report the observation of the longitudinal spin Seebeck effect in paramagnetic insulators. By using a microscale on-chip local heater, we generate a large thermal gradient confined to the chip surface without a large increase in the total sample temperature. Using this technique at low temperatures (<20??K), we resolve the paramagnetic spin Seebeck effect in the insulating paramagnets Gd3Ga5O12 (gadolinium gallium garnet) and DyScO3 (DSO), using either W or Pt as the spin detector layer. By taking advantage of the strong magnetocrystalline anisotropy of DSO, we eliminate contributions from the Nernst effect in W or Pt, which produces a phenomenologically similar signal. PMID:26001014

  11. Neuropsychological effects of marijuana

    PubMed Central

    Klonoff, Harry; Low, Morton; Marcus, Anthony

    1973-01-01

    This study assigned 81 non-naďve subjects, divided into low- and high-dose groups, to four experimental conditions (marijuana/marijuana, marijuana/placebo, placebo/marijuana and placebo/placebo) for two sessions separated by about one week. The low dose was 4.8 mg. ?9-THC followed by 2.4 mg. one hour later. The high dose was 9.1 mg. followed by 4.5 mg. one hour later. A battery of neuropsychological tests was administered. The low dose produced generalized impairment of all mental processes (concept formation, memory, tactile form discrimination and motor function) and the effect was generalized to all modalities. The high dose resulted in more extensive impairment, again generalized. The drug effects noted were explained in terms of generalized impairment of central integrative processes. The effects of marijuana on learning as well as memory were explained in terms of impaired output (recall), but the impairment was transient. PMID:4405419

  12. Spin Hall Effect Transistor

    NASA Astrophysics Data System (ADS)

    Wunderlich, Jörg; Park, Byong-Guk; Irvine, Andrew C.; Zârbo, Liviu P.; Rozkotová, Eva; Nemec, Petr; Novák, Vít; Sinova, Jairo; Jungwirth, Tomás

    2010-12-01

    The field of semiconductor spintronics explores spin-related quantum relativistic phenomena in solid-state systems. Spin transistors and spin Hall effects have been two separate leading directions of research in this field. We have combined the two directions by realizing an all-semiconductor spin Hall effect transistor. The device uses diffusive transport and operates without electrical current in the active part of the transistor. We demonstrate a spin AND logic function in a semiconductor channel with two gates. Our study shows the utility of the spin Hall effect in a microelectronic device geometry, realizes the spin transistor with electrical detection directly along the gated semiconductor channel, and provides an experimental tool for exploring spin Hall and spin precession phenomena in an electrically tunable semiconductor layer.

  13. Giving effective presentations.

    PubMed

    Englehart, Nadine

    2004-03-01

    Apprehension about oral communication, or public speaking is rated as the number one fear among most individuals. Developing skill in, and comfort with, public speaking is important whether we are presenting oral reports and proposals, responding to questions, or training co-workers. Effective speakers are able to communicate information in a way that stimulates interest, helps the audience to understand and remember, and influences attitudes and behaviours. Many of us think that effective speakers are born rather than made. In truth most successful speakers work hard and invest a great deal of time and effort in to improving their speaking capabilities. Effective public speaking is a learned skill and activity that requires lots of practice. Like other learned skills, having a strategy with clear action steps can help you achieve your goal. PMID:15116467

  14. Transgenerational genetic effects

    PubMed Central

    Nelson, Vicki R; Nadeau, Joseph H

    2012-01-01

    Since Mendel, studies of phenotypic variation and disease risk have emphasized associations between genotype and phenotype among affected individuals in families and populations. Although this paradigm has led to important insights into the molecular basis for many traits and diseases, most of the genetic variants that control the inheritance of these conditions continue to elude detection. Recent studies suggest an alternative mode of inheritance where genetic variants that are present in one generation affect phenotypes in subsequent generations, thereby decoupling the conventional relations between genotype and phenotype, and perhaps, contributing to ‘missing heritability’. Under some conditions, these transgenerational genetic effects can be as frequent and strong as conventional inheritance, and can persist for multiple generations. Growing evidence suggests that RNA mediates these heritable epigenetic changes. The primary challenge now is to identify the molecular basis for these effects, characterize mechanisms and determine whether transgenerational genetic effects occur in humans. PMID:22122083

  15. Relative age effect: implications for effective practice.

    PubMed

    Andronikos, Georgios; Elumaro, Adeboye Israel; Westbury, Tony; Martindale, Russell J J

    2016-06-01

    Physical and psychological differences related to birthdate amongst athletes of the same selection year have been characterised as the "relative age effects" (RAEs). RAEs have been identified in a variety of sports, both at youth and adult level, and are linked with dropout of athletes and a reduction of the talent pool. This study examined the existence, mechanisms and possible solutions to RAEs using qualitative methodology. Seven experts in the field of talent identification and development were interviewed. Inductive analysis of the data showed that, while there was mixed evidence for the existence of RAEs across sports, the eradication of RAEs was attributed to controllable features of the development environment. The factors reported included the structure of "categories" used to group athletes within the sport (e.g. age, weight, size, skills), recognition and prioritisation of long-term development over "short term win focus." Education of relevant parties (e.g. coaches, scouts, clubs) about RAEs and the nature of "talent" within a long-term context was suggested, along with careful consideration of the structure of the development environment (e.g. delayed selection, provision for late developers, focus on skills not results, use of challenge). Implications for research and practice are discussed. PMID:26417709

  16. Habituation of reinforcer effectiveness

    PubMed Central

    Lloyd, David R.; Medina, Douglas J.; Hawk, Larry W.; Fosco, Whitney D.; Richards, Jerry B.

    2014-01-01

    In this paper we propose an integrative model of habituation of reinforcer effectiveness (HRE) that links behavioral- and neural-based explanations of reinforcement. We argue that HRE is a fundamental property of reinforcing stimuli. Most reinforcement models implicitly suggest that the effectiveness of a reinforcer is stable across repeated presentations. In contrast, an HRE approach predicts decreased effectiveness due to repeated presentation. We argue that repeated presentation of reinforcing stimuli decreases their effectiveness and that these decreases are described by the behavioral characteristics of habituation (McSweeney and Murphy, 2009; Rankin etal., 2009). We describe a neural model that postulates a positive association between dopamine neurotransmission and HRE. We present evidence that stimulant drugs, which artificially increase dopamine neurotransmission, disrupt (slow) normally occurring HRE and also provide evidence that stimulant drugs have differential effects on operant responding maintained by reinforcers with rapid vs. slow HRE rates. We hypothesize that abnormal HRE due to genetic and/or environmental factors may underlie some behavioral disorders. For example, recent research indicates that slow-HRE is predictive of obesity. In contrast ADHD may reflect “accelerated-HRE.” Consideration of HRE is important for the development of effective reinforcement-based treatments. Finally, we point out that most of the reinforcing stimuli that regulate daily behavior are non-consumable environmental/social reinforcers which have rapid-HRE. The almost exclusive use of consumable reinforcers with slow-HRE in pre-clinical studies with animals may have caused the importance of HRE to be overlooked. Further study of reinforcing stimuli with rapid-HRE is needed in order to understand how habituation and reinforcement interact and regulate behavior. PMID:24409128

  17. Aharonov-Bohm effect revisited

    NASA Astrophysics Data System (ADS)

    Eskin, Gregory

    2015-04-01

    Aharonov-Bohm effect is a quantum mechanical phenomenon that attracted the attention of many physicists and mathematicians since the publication of the seminal paper of Aharonov and Bohm [1] in 1959. We consider different types of Aharonov-Bohm effects such as the magnetic AB effect, electric AB effect, combined electromagnetic AB effect, AB effect for the Schrödinger equations with Yang-Mills potentials, and the gravitational analog of AB effect. We shall describe different approaches to prove the AB effect based on the inverse scattering problems, the inverse boundary value problems in the presence of obstacles, spectral asymptotics, and the direct proofs of the AB effect.

  18. An acoustic Casimir effect

    NASA Astrophysics Data System (ADS)

    Larraza, Andrés; Denardo, Bruce

    1998-11-01

    Theoretical and experimental results are presented for the force law between two rigid, parallel plates due to the radiation pressure of band-limited acoustic noise. Excellent agreement is shown between theory and experiment. While these results constitute an acoustic analog for the Casimir effect, an important difference is that band-limited noise can cause the force to be attractive or repulsive as a function of the distance of separation of the plates. Applications of the acoustic Casimir effect to background noise transduction and non-resonant acoustic levitation are suggested.

  19. Nonequilibrium effects in Isoscaling

    SciTech Connect

    Dorso, C. O.; Lopez, J. A.

    2007-02-12

    In this work we study within a simple model different properties of the system that allow us to understand the properties of the isoscaling observable. We first show that isoscaling is a general property of fragmenting systems. We show this by using a simple generalized percolation model. We show that the usual isoscaling property can be obtained in the case of bond percolation in bichromatic lattices with any regular topology. In this case the probabilities of each color (isospin) are independent. We then explore the effect of introducing 'non-equilibrium' effects.

  20. Contamination effects study

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The in-situ optical surface measurement system is a facility designed to study the deleterious effects of particulate materials on the surface reflectivities of optical materials in the vacuum ultraviolet (VUV). This arrangement is designed to simulate the on-orbit effects of contamination and degradation of optical surfaces. This simulation is accomplished through the use of non-coherent VUV sources illuminating optical surfaces located in a high vacuum chamber. Several sources of contamination are employed. The reflectivity is measured both at the specular reflection as well as at two scattered positions, forward and reverse. The system components are described and an operating procedure is given.

  1. Effective Temperature of Mutations

    NASA Astrophysics Data System (ADS)

    Derényi, Imre; Szöll?si, Gergely J.

    2015-02-01

    Biological macromolecules experience two seemingly very different types of noise acting on different time scales: (i) point mutations corresponding to changes in molecular sequence and (ii) thermal fluctuations. Examining the secondary structures of a large number of microRNA precursor sequences and model lattice proteins, we show that the effects of single point mutations are statistically indistinguishable from those of an increase in temperature by a few tens of kelvins. The existence of such an effective mutational temperature establishes a quantitative connection between robustness to genetic (mutational) and environmental (thermal) perturbations.

  2. Vascular effects of flavonoids.

    PubMed

    Almeida Rezende, Bruno; Pereira, Aline Carvalho; Cortes, Steyner F; Lemos, Virginia Soares

    2016-01-01

    Flavonoids are natural plant-derived polyphenolic compounds with various biological properties particularly in the cardiovascular system, including antiatherogenic, antioxidant, vasodilation, antihypertensive, and antiplatelet activities. These biological properties have been evaluated in several experimental and clinical studies. In addition, extensive reviews have discussed the antiatherogenic effect of these polyphenols. However, limited studies have investigated the potential therapeutic vascular effects of these compounds. This review brings together some recent studies, to establish the different signaling pathways involved in the molecular mechanisms that underlie the vasodilation induced by flavonoids. PMID:26555950

  3. Anticancer effects of fucoidan.

    PubMed

    Senthilkumar, Kalimuthu; Kim, Se-Kwon

    2014-01-01

    Recently, there has been an increased interest in the pharmacologically active natural compounds isolated and used for remedies of various kinds of diseases, including cancer. The great deal of interest has been developed to isolate bioactive compounds from marine resources because of their numerous health beneficial effects. Among marine resources, marine algae are valuable sources of structurally diverse bioactive compounds. Fucoidan is a sulfated polysaccharide derived from brown seaweeds and has been used as an ingredient in some dietary supplement products. Fucoidan has various biological activities including antibacterial, antioxidant, anti-inflammatory, anticoagulant, and antitumor activities. So this chapter deals with anticancer effects of fucoidan. PMID:25081084

  4. Creating an Effective Newsletter

    ERIC Educational Resources Information Center

    Shackelford, Ray; Griffis, Kurt

    2006-01-01

    Newsletters are an important resource or form of media. They offer a cost-effective way to keep people informed, as well as to promote events and programs. Production of a newsletter makes an excellent project, relevant to real-world communication, for technology students. This article presents an activity on how to create a short newsletter. The…

  5. Cost effective technology

    NASA Astrophysics Data System (ADS)

    Miller, S. C.

    1989-09-01

    With relation to advanced technology for gas turbines, the overall process of product definition and development, concentrating particularly on the integration of activities between engineering design and manufacturing, is surveyed. The development of new philosophies in each of these spheres of activity is concluded to be cost effective technology and to make a highly significant contribution to the competitiveness and profitability of the industry.

  6. Effective Nonverbal Communication.

    ERIC Educational Resources Information Center

    Parratt, Smitty

    1995-01-01

    Discusses the importance of understanding nonverbal communication in enhancing the personal and work relationships of interpreters and increasing their effectiveness in meeting the needs of customers. Discusses the mystique of body language, cultural variation in the use of gestures, the stages of an encounter, interpreting gesture clusters, and…

  7. Assessing Library Effectiveness.

    ERIC Educational Resources Information Center

    Shaughnessy, Thomas W.

    1990-01-01

    Discusses the current emphasis on assessment of library effectiveness and describes several assessment techniques. It is argued that, by encouraging staff to develop an attitude of self-assessment based on their ability to add value to library services, the assessment phenomenon can be used to improve the overall quality of libraries. (11…

  8. Educator Effectiveness Administrative Manual

    ERIC Educational Resources Information Center

    Pennsylvania Department of Education, 2014

    2014-01-01

    The goal of this manual is to provide guidance in the evaluation of educators, highlight critical components of effectiveness training, and offer opportunities for professional growth. The term "educator" includes teachers, all professional and temporary professional employees, education specialists, and school administrators/principals.…

  9. Effective Team Participation.

    ERIC Educational Resources Information Center

    Male, Mary

    1991-01-01

    The Student Study Team (SST) is described as a California intervention model that encourages effective multidisciplinary team participation. The development, training, operation, and evaluation of such teams are discussed, and implementation recommendations are offered. The article includes a flow chart of the SST process, a meeting competency…

  10. Biasing Effects of Experimenters.

    ERIC Educational Resources Information Center

    Rosenthal, Robert

    1977-01-01

    Explains the types of effects, usually unintentional, that psychologists can have upon the results of their research; describes the "Pygmalion Experiment," in which teachers' expectations for children's behavior proved to be self-fulfilling prophecies; and points to research needs in the area of interpersonal expectations. (GT)

  11. Building Effective Afterschool Programs.

    ERIC Educational Resources Information Center

    Fashola, Olatokunbo S.

    Through a comprehensive review of various afterschool programs across the United States, this resource provides a practical overview of the research and best practices that can be easily adapted and applied in the development of highly effective afterschool programs. chapters focus on: (1) "Why Afterschool Programs?" (benefits, challenges, and…

  12. Microcircuit radiation effects databank

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Radiation test data submitted by many testers is collated to serve as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. Total dose damage information and single event upset cross sections, i.e., the probability of a soft error (bit flip) or of a hard error (latchup) are presented.

  13. Camp's "Disneyland" Effect.

    ERIC Educational Resources Information Center

    Renville, Gary

    1999-01-01

    Describes the positive mental, physical, and social growth impacts that the camping experience had on the author, and urges camp program evaluation to plan and implement such changes. Sidebar lists steps of effective evaluation: program goals and objectives, goals of evaluation, implementation of evaluation, data analysis, and findings and…

  14. Tips for Effective Management

    ERIC Educational Resources Information Center

    Supple, Kevin F.

    2009-01-01

    School business officials' days are filled with numbers and reports--audits, balance sheets, check registers, financial statements, journal entries, vouchers, and warrant reports, just to name a few. Those are all important tools that school business officers use to manage the financial resources of the district effectively. However, they are also…

  15. Are Charter Schools Effective?

    ERIC Educational Resources Information Center

    Garrison, Lawrence F.; Holifield, Mitchell

    2005-01-01

    Within the context of continual dissatisfaction with American public schools, charter school proponents view charter schools as a viable reform mechanism. Here, Garrison and Holifield compare the perceptions of charter school principals regarding the extent to which the effective school correlates have been implemented in their respective schools…

  16. Case 26: Somogyi effect

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This individual has a classic manifestation of the Somogyi effect, which is fasting morning hyperglycemia in response to hypoglycemia in the early morning and late night hours. The danger is that if night-time blood glucose levels are not measured, the physician may interpret the patient as having h...

  17. Institute Effectiveness through Marketing.

    ERIC Educational Resources Information Center

    Cameron, B. J.

    1984-01-01

    An institution with a marketing orientation can (1) recognize shifts in the market and in perceptions of activities of significant markets or competing institutions and (2) respond to them. Institutions with strategic marketing may be better able to predict or influence market shifts and be judged as effective in the areas it prefers. (MSE)

  18. Learning to Effect.

    ERIC Educational Resources Information Center

    Barnett, Ronald, Ed.

    This book presents 14 papers which discuss contemporary issues of curriculum change and instructional effectiveness in higher education primarily from a British perspective. Papers address curriculum purpose, curriculum delivery, and curriculum impact on the wider society. In addition, the book covers experiential learning, skills and training,…

  19. Effective Classroom Management

    ERIC Educational Resources Information Center

    Mansor, Azlin Norhaini; Eng, Wong Kim; Rasul, Mohamad Sattar; Hamzah, Mohd Izham Mohd; Hamid, Aida Hanim A.

    2012-01-01

    This paper attempts to explore and identify the characteristics of an effective teacher who teaches English as a second language to 10 year old students from different ethnics, various social economic background and multi-level language ability, at a private primary school in Malaysia. The study focused on classroom management using a case study…

  20. Alexandrite effect spectropyrometer

    NASA Astrophysics Data System (ADS)

    Liu, Yan

    2006-08-01

    Alexandrite crystal is commonly used for making alexandrite laser, and it also has a less-known phenomenon called the alexandrite effect that refers to the color change between different light sources. A novel spectropyrometer for temperature measurement of a radiating body utilizing the alexandrite effect is introduced. The alexandrite effect method for temperature measurement is based on the relationship between the temperature of blackbody and the hue-angle in the CIELAB color space. The alexandrite effect spectropyrometer consists of an optical probe, a spectrometer, a computer, and an alexandrite filter. It measures the spectral power distribution of a radiating body through the alexandrite filter, calculates the hue-angle, and determines the temperature. The spectropyrometer is suitable for temperature measurement of any radiating body with or without spectral lines in its spectral power distribution from 1000 K to 100000 K. The spectropyrometer is particularly useful for high to ultrahigh temperature measurement of any radiating bodies with spectral line emissions, such as electric arcs and discharges, plasmas, and high temperature flames.

  1. Cost Effective Prototyping

    NASA Technical Reports Server (NTRS)

    Wickman, Jerry L.; Kundu, Nikhil K.

    1996-01-01

    This laboratory exercise seeks to develop a cost effective prototype development. The exercise has the potential of linking part design, CAD, mold development, quality control, metrology, mold flow, materials testing, fixture design, automation, limited parts production and other issues as related to plastics manufacturing.

  2. Explaining Charter School Effectiveness

    ERIC Educational Resources Information Center

    Angrist, Joshua D.; Pathak, Parag A.; Walters, Christopher R.

    2012-01-01

    This study uses entrance lotteries to explore heterogeneity in the achievement effects of charter schools across demographic groups and between urban and non-urban areas in Massachusetts. The authors develop a framework for interpreting this heterogeneity using both student- and school-level explanatory variables. (Contains 4 tables.)

  3. Radiation: Doses, Effects, Risks.

    ERIC Educational Resources Information Center

    Lean, Geoffrey, Ed.

    Few scientific issues arouse as much public controversy as the effects of radiation. This booklet is an attempt to summarize what is known about radiation and provide a basis for further discussion and debate. The first four chapters of the booklet are based on the most recent reports to the United Nations' General Assembly by the United Nations…

  4. Reporting Research Results Effectively

    ERIC Educational Resources Information Center

    Volkwein, J. Fredericks

    2010-01-01

    Assessment research is at its best when it packages research results and data so that they can be digested by multiple audiences. Too many assessment researchers spend all their efforts planning and executing the research project with little attention to closing the loop at the end. If assessment findings are not communicated effectively, the…

  5. Contamination Effects Test Facility

    NASA Astrophysics Data System (ADS)

    Shaw, C. G.; Thornton, M. M.; Mullen, C. R.

    1987-01-01

    A test facility has been developed for in-situ measurement of the thermo-optical and electrical effects of molecular contamination deposited on sensitive spacecraft surfaces. The Contamination Effects Test Facility (CETF) consists of three separate vacuum chambers interconnected by gate valves through which test sample surfaces may be moved as needed by various vacuum manipulators. Deposition of contamination occurs in one chamber, where surface electrical properties can also be measured. In the second chamber, a wide range of thermo-optical properties can be measured by use of a unique ellipsoidal-mirror reflectometer. The third chamber maintains a vacuum environment around the test sample while the chamber is transported to facilities for solar ultraviolet (UV), electron, and proton irradiation of the sample at orbital intensities. By keeping atmosphere away from the contaminated surface at all times during the effects measurement and irradiation stages, the CETF provides a more realistic space simulation that avoids the possible effects of oxygen and water on the thermo-optical or electrical properties of the contaminant deposits. For testing of the volatile species produced by rocket propulsion systems, which are condensible only at cryogenic temperatures, continual vacuum capability precludes rapid icing due to atmospheric water vapor.

  6. EFFECTS ON SALTWATER ORGANISMS

    EPA Science Inventory

    The literature review summarizes current data on the effects of pesticides and metals on marine organisms, aquatic environmental research methods, bioaccumulation of pollutants by estuarine and marine organisms and in water/sediment residues and biota. Results of studies of the e...

  7. FIELD DISPERSANT EFFECTIVENESS TEST

    EPA Science Inventory

    The EPA's OHMSETT facility has developed a rapid field test that includes some of the theoretical aspects and conditions of dispersion at sea. This Field Dispersant Effectiveness Test (FDET) has been used to evaluate the dispersibility of various commonly-transported oils and mak...

  8. Designing "Educationally Effective" Discussion

    ERIC Educational Resources Information Center

    Swann, Joan

    2007-01-01

    This paper analyses data from a curriculum intervention project designed to introduce new forms of discussion, seen as educationally effective, into the primary classroom. While the introduction of talk as an aid to learning is premised on a social approach to learning, such interventions are often evaluated in terms of cognitive benefits and…

  9. Desert Storm environmental effects

    NASA Astrophysics Data System (ADS)

    Kimball, E. W.

    It is noted that after more than six months of operation of the Patriot launch station in the Saudi Arabian desert no problems that were attributed to high temperature occurred. The environmental anomalies that did occur were cosmetic in nature and related to dust and salt fog. It was concluded that the Desert Storm environmental effects were typical of worldwide hot, dry climates.

  10. BIOLOGICAL EFFECTS OF MANGANESE

    EPA Science Inventory

    The biological effects of manganese were studied in a town on the coast of Dalmatia in which a ferromanganese plant has been operating since before World War II. The study focused on the question of whether the exposure to manganese can cause a higher incidence of respiratory dis...

  11. DCPS Effective Schools Framework

    ERIC Educational Resources Information Center

    District of Columbia Public Schools, 2009

    2009-01-01

    DCPS is committed to providing "all" students with the caliber of education they deserve. The goal of the DCPS Effective Schools Framework is to ensure that every child, in every classroom, has access to a high-quality and engaging standards-based instructional program, and that all school supports are aligned to support teaching and learning. The…

  12. What Effective Schools Do

    ERIC Educational Resources Information Center

    West, Martin R.; Gabrieli, Christopher F. O.; Finn, Amy S.; Kraft, Matthew A.; Gabrieli, John D. E.

    2014-01-01

    Research has been showing that the most important development in K-12 education over the past decade has been the emergence of a growing number of urban schools that have been convincingly shown to have dramatic positive effects on the achievement of disadvantaged students. Those with the strongest evidence of success are oversubscribed charter…

  13. Space Environmental Effects Knowledgebase

    NASA Technical Reports Server (NTRS)

    Wood, B. E.

    2007-01-01

    This report describes the results of an NRA funded program entitled Space Environmental Effects Knowledgebase that received funding through a NASA NRA (NRA8-31) and was monitored by personnel in the NASA Space Environmental Effects (SEE) Program. The NASA Project number was 02029. The Satellite Contamination and Materials Outgassing Knowledgebase (SCMOK) was created as a part of the earlier NRA8-20. One of the previous tasks and part of the previously developed Knowledgebase was to accumulate data from facilities using QCMs to measure the outgassing data for satellite materials. The main object of this current program was to increase the number of material outgassing datasets from 250 up to approximately 500. As a part of this effort, a round-robin series of materials outgassing measurements program was also executed that allowed comparison of the results for the same materials tested in 10 different test facilities. Other programs tasks included obtaining datasets or information packages for 1) optical effects of contaminants on optical surfaces, thermal radiators, and sensor systems and 2) space environmental effects data and incorporating these data into the already existing NASA/SEE Knowledgebase.

  14. Facilitating Online Discussions Effectively

    ERIC Educational Resources Information Center

    Rovai, Alfred P.

    2007-01-01

    This article presents a synthesis of the theoretical and research literature on facilitating asynchronous online discussions effectively. Online courses need to be designed so that they provide motivation for students to engage in productive discussions and clearly describe what is expected, perhaps in the form of a discussion rubric.…

  15. The Negative Repetition Effect

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Peterson, Daniel J.

    2013-01-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising "negative repetition effect," in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and…

  16. Effective Staff Development.

    ERIC Educational Resources Information Center

    Bush, Robert N.

    Beginning with the observation that educators are faced with rising public expectations, declining resources, and increased public criticism, this paper describes a six-fold model for determining how staff development is operating and how it can be made to operate more effectively, in a self-renewing manner. The six dimensions consist of the…

  17. Measuring Institutional Effectiveness.

    ERIC Educational Resources Information Center

    Macomb County Community Coll., Warren, MI.

    The measurement of institutional effectiveness involves a systematic comparison of organizational purpose and performance. For community colleges, organizational purpose can be defined in terms of providing access to education, realizing student achievement, promoting student development, or addressing social needs. If all four purposes are…

  18. Enhancing Community Board Effectiveness.

    ERIC Educational Resources Information Center

    Hurley, Daniel J.; Santos, Alan

    The effectiveness of the community board in the mental health system specifically and in human service systems generally depends, to a large extent, on how the board's role and scope are defined and how its organizational structure and staffing procedures are developed. The development of community boards should be based upon the premises that (1)…

  19. Using Your Library Effectively.

    ERIC Educational Resources Information Center

    Hennepin County Library, Minnetonka, MN.

    This collection of materials for a three-hour instructional program for young people and adults in the effective use of the public library includes an introduction to the program, a teaching guide for the librarian, a packet of materials for students, and a summary of 90 evaluations of the program as it was presented at two area libraries and…

  20. What Effective Schools Do

    ERIC Educational Resources Information Center

    West, Martin R.; Gabrieli, Christopher F. O.; Finn, Amy S.; Kraft, Matthew A.; Gabrieli, John D. E.

    2014-01-01

    Research has been showing that the most important development in K-12 education over the past decade has been the emergence of a growing number of urban schools that have been convincingly shown to have dramatic positive effects on the achievement of disadvantaged students. Those with the strongest evidence of success are oversubscribed charter…

  1. Qualities of Effective Principals

    ERIC Educational Resources Information Center

    Stronge, James H.; Richard, Holly B.; Catano, Nancy

    2008-01-01

    You know how important principals are in advancing student achievement and school success, but it's not been exactly clear which components of the principal's job are the highest priority... until now. Following on the results-based approach from the ASCD best-seller "Qualities of Effective Teachers", James Stronge and his coauthors explain how…

  2. Is Effective Teaching Stable?

    ERIC Educational Resources Information Center

    Patrick, Helen; Mantzicopoulos, Panayota

    2016-01-01

    The authors examined the ecological validity of using observation-based scores to evaluate individual teachers' effectiveness, mirroring their use by school administrators. Using the Classroom Assessment Scoring System, the authors asked (a) how similar are teachers' emotional support, classroom organization, and instructional support scores from…

  3. Commentary: Expanding on Effectiveness

    ERIC Educational Resources Information Center

    Pelham, William E., Jr.; Massetti, Greta M.

    2003-01-01

    Atkins, Graczyk, Frazier, and Abdul-Adil (2003) make the point that there have been three limitations of mental health services for children and families in low-income, urban settings: (a) accessibility; (b) effectiveness; and (c) sustainability. Their article focuses extensively on improving access and addressing issues of sustainability in…

  4. Developing Effective Training Programs.

    ERIC Educational Resources Information Center

    Wagonhurst, Carole

    2002-01-01

    Focusing on research administrators, discusses how an effective training program improves employee performance by including comprehensive needs assessment, employing appropriate training methodologies, and anticipating factors beyond the actual training event that influence the transfer of skills from the training environment to the work…

  5. Marijuana: respiratory tract effects.

    PubMed

    Owen, Kelly P; Sutter, Mark E; Albertson, Timothy E

    2014-02-01

    Marijuana is the most commonly used drug of abuse in the USA. It is commonly abused through inhalation and therefore has effects on the lung that are similar to tobacco smoke, including increased cough, sputum production, hyperinflation, and upper lobe emphysematous changes. However, at this time, it does not appear that marijuana smoke contributes to the development of chronic obstructive pulmonary disease. Marijuana can have multiple physiologic effects such as tachycardia, peripheral vasodilatation, behavioral and emotional changes, and possible prolonged cognitive impairment. The carcinogenic effects of marijuana are unclear at this time. Studies are mixed on the ability of marijuana smoke to increase the risk for head and neck squamous cell carcinoma, lung cancer, prostate cancer, and cervical cancer. Some studies show that marijuana is protective for development of malignancy. Marijuana smoke has been shown to have an inhibitory effect on the immune system. Components of cannabis are under investigation as treatment for autoimmune diseases and malignancy. As marijuana becomes legalized in many states for medical and recreational use, other forms of tetrahydrocannabinol (THC) have been developed, such as food products and beverages. As most research on marijuana at this time has been on whole marijuana smoke, rather than THC, it is difficult to determine if the currently available data is applicable to these newer products. PMID:23715638

  6. Making Effective Assignments.

    ERIC Educational Resources Information Center

    McLeod, Alan M., Ed.

    1982-01-01

    Although the focus of this issue of the "Virginia English Bulletin" is on making effective assignments, most of the articles also emphasize the importance and power of writing. Articles deal with the following topics: (1) the use of I-search (as explained by Kenneth Macrorie in "Searching Writing") as a form of research paper that narrates the…

  7. EFFECTIVE USE OF PHEROMONES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective integrated pest management programs are needed for food processing and storage facilities and this requires improvements in our ability to monitor pest populations and use this information to target management tactics in both time and space. The use of pheromone traps to detect pests is i...

  8. Creating an Effective Newsletter

    ERIC Educational Resources Information Center

    Shackelford, Ray; Griffis, Kurt

    2006-01-01

    Newsletters are an important resource or form of media. They offer a cost-effective way to keep people informed, as well as to promote events and programs. Production of a newsletter makes an excellent project, relevant to real-world communication, for technology students. This article presents an activity on how to create a short newsletter. The…

  9. Reporting Research Results Effectively

    ERIC Educational Resources Information Center

    Volkwein, J. Fredericks

    2010-01-01

    Assessment research is at its best when it packages research results and data so that they can be digested by multiple audiences. Too many assessment researchers spend all their efforts planning and executing the research project with little attention to closing the loop at the end. If assessment findings are not communicated effectively, the…

  10. Confirming Testlet Effects

    ERIC Educational Resources Information Center

    DeMars, Christine E.

    2012-01-01

    A testlet is a cluster of items that share a common passage, scenario, or other context. These items might measure something in common beyond the trait measured by the test as a whole; if so, the model for the item responses should allow for this testlet trait. But modeling testlet effects that are negligible makes the model unnecessarily…

  11. The Negative Repetition Effect

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Peterson, Daniel J.

    2013-01-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising "negative repetition effect," in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and…

  12. Adverse effects of cannabis.

    PubMed

    2011-01-01

    Cannabis, Cannabis sativa L., is used to produce a resin that contains high levels of cannabinoids, particularly delta9-tetrahydrocannabinol (THC), which are psychoactive substances. Although cannabis use is illegal in France and in many other countries, it is widely used for its relaxing or euphoric effects, especially by adolescents and young adults. What are the adverse effects of cannabis on health? During consumption? And in the long term? Does cannabis predispose users to the development of psychotic disorders? To answer these questions, we reviewed the available evidence using the standard Prescrire methodology. The long-term adverse effects of cannabis are difficult to evaluate. Since and associated substances, with or without the user's knowledge. Tobacco and alcohol consumption, and particular lifestyles and behaviours are often associated with cannabis use. Some traits predispose individuals to the use of psychoactive substances in general. The effects of cannabis are dosedependent.The most frequently report-ed adverse effects are mental slowness, impaired reaction times, and sometimes accentuation of anxiety. Serious psychological disorders have been reported with high levels of intoxication. The relationship between poor school performance and early, regular, and frequent cannabis use seems to be a vicious circle, in which each sustains the other. Many studies have focused on the long-term effects of cannabis on memory, but their results have been inconclusive. There do not * About fifteen longitudinal cohort studies that examined the influence of cannabis on depressive thoughts or suicidal ideation have yielded conflicting results and are inconclusive. Several longitudinal cohort studies have shown a statistical association between psychotic illness and self-reported cannabis use. However, the results are difficult to interpret due to methodological problems, particularly the unknown reliability of self-reported data. It has not been possible to establish a causal relationship in either direction, because of these methodological limitations. In Australia, the marked increase in cannabis use has not been accompanied by an increased incidence of schizophrenia. On the basis of the available data, we cannot reach firm conclusions on whether or not cannabis use causes psychosis. It seems prudent to inform apparently vulnerable individuals that cannabis may cause acute psychotic decompensation, especially at high doses. Users can feel dependent on cannabis, but this dependence is usually psychological. Withdrawal symptoms tend to occur within 48 hours following cessation of regular cannabis use, and include increased irritability, anxiety, nervousness, restlessness, sleep difficulties and aggression. Symptoms subside within 2 to 12 weeks. Driving under the influence of cannabis doubles the risk of causing a fatal road accident. Alcohol consumption plays an even greater role. A few studies and a number of isolated reports suggest that cannabis has a role in the occurrence of cardiovascular adverse effects, especially in patients with coronary heart disease. Numerous case-control studies have investigated the role of cannabis in the incidence of some types of cancer. Its role has not been ruled out, but it is not possible to determine whether the risk is distinct from that of the tobacco with which it is often smoked. Studies that have examined the influence of cannabis use on the clinical course of hepatitis C are inconclusive. Alcohol remains the main toxic agent that hepatitis C patients should avoid. In practice, the adverse effects of low-level, recreational cannabis use are generally minor, although they can apparently be serious in vulnerable individuals. The adverse effects of cannabis appear overall to be less serious than those of alcohol, in terms of neuropsychological and somatic effects, accidents and violence. PMID:21462790

  13. Effects of Medications on Voice

    MedlinePLUS

    ... Meeting Calendar Find an ENT Doctor Near You Effects of Medications on Voice Effects of Medications on Voice Patient Health Information News ... replacement therapy post-menopause may have a variable effect. An inadequate level of thyroid replacement medication in ...

  14. Health Effects of Air Pollution

    MedlinePLUS

    ... Health effects of air pollution Health effects of air pollution Breathing air that is not clean can hurt ... important to know about the health effects that air pollution can have on you and others. Once you ...

  15. Stormwater BMP Effectiveness Assessment Toolkit

    EPA Science Inventory

    US EPA has identified stormwater BMP effectiveness as a priority research need. Effective protection of biotic integrity requires that processes maintaining the diversity of physical habitats be protected. Methods are needed to evaluate the effectiveness of existing Stormwater ...

  16. Being an effective speaker.

    PubMed

    Davidhizar, R; Cosgray, R

    1991-08-01

    Communication in a group is an essential quality for success in nursing. Despite this, many nurses who must have communication skills to advance have little training in public speaking. Some nurses seek to correct such deficiencies in their education by taking courses in the evenings or on weekends to improve their understanding of the elements of effective speaking. Other nurses learn by self-reflection, study, and ongoing practice. This article has presented guidelines for speaking in a group that can offer assistance in mastering this important nursing skill. Elements of nonverbal communication are crucial for effective communication. However, despite the importance of non-verbal communication to the message, language is what makes communication possible. It is language that allows people to communicate new ideas and thoughts and to solve problems. PMID:1877075

  17. Cerebroprotective effect of flunarizine.

    PubMed

    Nikolov, R; Nikolova, M; Dikova, M; Mirzoyan, R S; Ganshina, T S; Volobueva, T I

    1990-01-01

    The cerebroprotective effect of flunarizine was studied using the following methods: hypobaric hypoxia in mice, complete ischemia by decapitation in mice, anoxic hypoxia in mice, hemic hypoxia in rats, incomplete ischemia by bilateral carotid ligation in rats and asphyxic hypoxia in cats. Piracetam, meclofenoxate, nicergoline, naftidrofuryl, cinnarizine and nifedipine were studied as reference drugs. Flunarizine increased the survival time in all survival models. Its effect was most pronounced in complete ischemia model, and considerably higher than that of reference drugs. In asphyxic hypoxia flunarizine increased cortical resistance and shortened cortical recovery. The EEG frequency-amplitude analysis during asphyxic hypoxia showed a significant decrease of the slow-waves amplitudes of delta and theta range, and an increase of the fast-waves amplitudes of beta-2 range, changes indicating protective action. PMID:2087140

  18. Lightning Physics and Effects

    NASA Astrophysics Data System (ADS)

    Orville, Richard E.

    2004-03-01

    Lightning Physics and Effects is not a lightning book; it is a lightning encyclopedia. Rarely in the history of science has one contribution covered a subject with such depth and thoroughness as to set the enduring standard for years, perhaps even decades, to come. This contribution covers all aspects of lightning, including lightning physics, lightning protection, and the interaction of lightning with a variety of objects and systems as well as the environment. The style of writing is well within the ability of the technical non-expert and anyone interested in lightning and its effects. Potential readers will include physicists; engineers working in the power industry, communications, computer, and aviation industries; atmospheric scientists; geophysicists; meteorologists; atmospheric chemists; foresters; ecologists; physicians working in the area of electrical trauma; and, lastly, architects. This comprehensive reference volume contains over 300 illustrations, 70 tables with quantitative information, and over 6000 reference and bibliography entries.

  19. Developmental effects of dioxins.

    PubMed Central

    Birnbaum, L S

    1995-01-01

    The potent developmental toxicity of dioxin in multiple species has been known for a number of years. However, recent studies have indicated that dioxin also induces functional developmental defects, many of which are delayed. Subtle structural deficits, not detectable at birth, have also been described in multiple species and in both sexes. Certain defects have been reported not only in animals but also in children prenatally exposed to complex mixtures containing dioxinlike compounds. None of the effects can be attributed to modulation of any one endocrine system. For example, dioxin does not bind to the estrogen receptor, but it can cause effects that are both estrogenic and antiestrogenic. However, viewing dioxin and related compounds as endocrine disruptors that may alter multiple pathways sheds some light on the complexities of this potent class of growth dysregulators. PMID:8593882

  20. Leptophilic effective WIMPs

    NASA Astrophysics Data System (ADS)

    Chang, Spencer; Edezhath, Ralph; Hutchinson, Jeffrey; Luty, Markus

    2014-07-01

    Effective weakly interacting massive particle (WIMP) models are minimal extensions of the standard model that explain the relic density of dark matter by the "WIMP miracle." In this paper we consider the phenomenology of effective WIMPs with trilinear couplings to leptons and a new "lepton partner" particle. The observed relic abundance fixes the strength of the cubic coupling, so the parameters of the models are defined by the masses of the WIMP and lepton partner particles. This gives a simple parameter space where collider and direct detection experiments can be compared under well-defined physical minimality assumptions. The most sensitive collider probe is the search for leptons+MET, while the most sensitive direct detection channel is scattering from nuclei arising from loop diagrams. Collider and direct detection searches are highly complementary: colliders give the only meaningful constraint when dark matter is its own antiparticle, while direct detection is generally more sensitive if the dark matter is not its own antiparticle.

  1. Fuel Vaporization Effects

    NASA Technical Reports Server (NTRS)

    Bosque, M. A.

    1983-01-01

    A study of the effects of fuel-air preparation characteristics on combustor performance and emissions at temperature and pressure ranges representative of actual gas turbine combustors is discussed. The effect of flameholding devices on the vaporization process and NOx formation is discussed. Flameholder blockage and geometry are some of the elements that affect the recirculation zone characteristics and subsequently alter combustion stability, emissions and performance. A water cooled combustor is used as the test rig. Preheated air and Jet A fuel are mixed at the entrance of the apparatus. A vaporization probe is used to determine percentage of vaporization and a gas sample probe to determine concentration of emissions in the exhaust gases. The experimental design is presented and experimental expected results are discussed.

  2. Effective Vaccination Policies

    PubMed Central

    Shaw, L.; Spears, W.; Billings, L.; Maxim, P.

    2010-01-01

    We present a framework for modeling the spread of pathogens throughout a population and generating policies that minimize the impact of those pathogens on the population. This framework is used to study the spread of human viruses between cities via airplane travel. It combines agent-based simulation, mathematical analysis, and an Evolutionary Algorithm (EA) optimizer. The goal of this study is to develop tools that determine the optimal distribution of a vaccine supply in the model. Using plausible benchmark vaccine allocation policies of uniform and proportional distribution, we compared their effectiveness to policies found by the EA. We then designed and tested a new, more effective policy which increased the importance of vaccinating smaller cities that are flown to more often. This “importance factor” was validated using U.S. influenza data from the last four years. PMID:21057602

  3. Nonequilibrium effects and baryogenesis

    SciTech Connect

    Charng, Y.-Y.; Ng, K.-W.; Lee, D.-S.; Leung, C.N.

    2005-12-15

    Possible effects due to nonequilibrium dynamics in the Affleck-Dine mechanism of baryogenesis are examined. Using the closed-time-path formalism, the quantum fluctuation and the backreaction of the Affleck-Dine scalar field are incorporated self-consistently into the dynamical equations of the system by invoking a nonperturbative Hartree approximation. It is found that such nonequilibrium effects can significantly affect the amount of baryon asymmetry that can be generated. In particular, it is possible to generate the observed baryon asymmetry with suitable initial conditions. The methodology described in this paper as well as some of the results obtained are quite general, and can be applied to any complex scalar field in a cosmological background.

  4. Effectively managing wound exudate.

    PubMed

    Chamanga, Edwin

    2015-09-01

    The management of wound exudate remains a clinical challenge despite technological advances in products with better exudate-handling capacities. This clinical challenge is occasionally encountered when thick exudate (viscous exudate) is present, and when most modern dressings do not possess the capabilities to manage the viscosity while enabling exudate absorption. Maceration to the peri-wound area poses another challenge, irrespective of the number of topical barrier application products on the market and the innovation of dressing products that lock exudate away or those that encourage vertical wicking. In addition to all the above, in clinical practice, the assessment and documentation of wound exudate remains sporadic, leading to the challenges of effective wound exudate dressing selection and cost-effective dressings. PMID:26322408

  5. Safety Intervention Effectiveness

    SciTech Connect

    ZIMMERMAN, R.O.

    2001-10-16

    Judging safety intervention effectiveness is often left up to the eye of the beholder. Safety and Health Professionals must increase skills and increase their body of knowledge, based on scientific evidence, that can be applied confidently in the workplace. Evidence must be collected and analyzed to separate the interventions of the month with those that stand the test of time. The book Guide to Evaluating the Effectiveness of Strategies for Preventing Work injuries DHHS (NIOSH) Publication No. 2001-119, April 2001, serves as a primary reference. An example study related to biorhythms, popular in the late 1970s, is used to illustrate the separating of scientific evidence and pseudo-science hype. The cited biorhythm study focuses on the relationship of the accident dates and the three biorhythmic cycles (physical, emotional, and intelligence).

  6. Curvature effects in interferometry

    SciTech Connect

    Anandan, J.

    1984-10-15

    The phase shift in interferometry due to the space-time curvature is computed in nonrelativistic and relativistic physics. This treatment is applied to an interferometer analogous to the perfect crystal interferometer used in the Colella-Overhauser-Werner experiment with thermal neutrons, an interferometer consisting of only horizontal mirrors, suitable for ultracold neutrons, and optical interferometry. Experiments are proposed to detect the effect of the tidal forces of the Earth, Moon, and the Sun, for the first time in interferometry. The phase shift in neutron interferometry due to terrestrial objects is considered and an experiment is proposed with superfluid helium as the source of gravity. This would provide, for the first time, direct evidence concerning the gravitational interaction between two quantum-mechanical states. The possibility of detecting purely general-relativistic effects due to curvature, by means of neutron interferometry, is also explored.

  7. Effective plasma inductance computation

    SciTech Connect

    Maslovsky, Dmitry A.; Boozer, Allen H.

    2005-04-15

    The calculation of the resistive wall modes and their feedback stabilization is greatly simplified by splitting the plasma response from that of the external conductors. Existing calculations either consider highly simplified models of the external conductors or assume the plasma response can be approximated by a single rigid mode. The full response of an ideal, nonrotating plasma to perturbations that evolve slowly compared to the Alfven time is contained in the matrix for the effective plasma inductance {lambda}<=>. This matrix can be used in a code that accurately calculates the effects of the external conductors to obtain an essentially complete description of both plasma and the conducting structures. Calculations of {lambda}<=> for a number of tokamak equilibria are given together with an explanation of how the calculations are made and why they are important.

  8. Establishing effective working relationships.

    PubMed

    Houghton, Trish

    2016-02-24

    This article, the second in a series of 11, provides support and offers advice to new and existing mentors and practice teachers to enable them to progress in their role and develop a portfolio of evidence. In particular, the article discusses how to establish effective working relationships and emphasises the importance of the student-mentor or student-practice teacher relationship. It examines the essential qualities, attributes and characteristics of an effective mentor or practice teacher. The article provides learning activities and suggests ways in which mentors and practice teachers can undertake various self-assessments, enabling them to gather relevant evidence to demonstrate how they can meet and maintain the requirements for these roles as stipulated by the Nursing and Midwifery Council. PMID:26907148

  9. Observables in effective gravity

    SciTech Connect

    Giddings, Steven B.; Marolf, Donald; Hartle, James B.

    2006-09-15

    We address the construction and interpretation of diffeomorphism-invariant observables in a low-energy effective theory of quantum gravity. The observables we consider are constructed as integrals over the space of coordinates, in analogy to the construction of gauge-invariant observables in Yang-Mills theory via traces. As such, they are explicitly nonlocal. Nevertheless we describe how, in suitable quantum states and in a suitable limit, the familiar physics of local quantum field theory can be recovered from appropriate such observables, which we term ''pseudolocal.'' We consider measurement of pseudolocal observables, and describe how such measurements are limited by both quantum effects and gravitational interactions. These limitations support suggestions that theories of quantum gravity associated with finite regions of spacetime contain far fewer degrees of freedom than do local field theories.

  10. Polarization effects. Volume 2

    SciTech Connect

    Courant, E.

    1981-01-01

    The use of polarized proton beams in ISABELLE is important for several general reasons: (1) With a single longitudinally polarized proton beam, effects involving parity violation can be identified and hence processes involving weak interactions can be separated from those involving strong and electromagnetic interactions. (2) Spin effects are important in the strong interactions and can be useful for testing QCD. The technique for obtaining polarized proton beams in ISABELLE appears promising, particularly in view of the present development of a polarized proton beam for the AGS. Projections for the luminosity in ISABELLE for collisions of polarized protons - one or both beams polarized with longitudinal or transverse polarization - range from 1/100 to 1 times the luminosity for unpolarized protons.

  11. Latent effects decision analysis

    DOEpatents

    Cooper, J. Arlin; Werner, Paul W.

    2004-08-24

    Latent effects on a system are broken down into components ranging from those far removed in time from the system under study (latent) to those which closely effect changes in the system. Each component is provided with weighted inputs either by a user or from outputs of other components. A non-linear mathematical process known as `soft aggregation` is performed on the inputs to each component to provide information relating to the component. This information is combined in decreasing order of latency to the system to provide a quantifiable measure of an attribute of a system (e.g., safety) or to test hypotheses (e.g., for forensic deduction or decisions about various system design options).

  12. Magnetic effects on thermocouples

    NASA Astrophysics Data System (ADS)

    Beguš, Samo; Bojkovski, Jovan; Drnovšek, Janko; Geršak, Gregor

    2014-03-01

    Thermometers in laboratory environment and industrial applications are often subject to extraneous, usually unwanted and uncontrolled magnetic fields. Magnetic field influence can be minimized, but cannot be fully cancelled out. Even more, in most cases, there is no awareness of the existence of magnetic fields, let alone their effect on measurement instrumentation. In the past, sensitivity to high dc magnetic fields has been investigated in cryogenics and at high temperatures. More recently, the magnetic effect on weak dc magnetic fields was presented. The goal of this paper was to analyse and empirically and experimentally prove the magnetic sensitivity of thermocouples exposed to low magnetic fields: both dc and ac. Precision and uniform alternating and direct magnetic flux densities were generated by means of permanent magnets and power amplifiers with air-cored coils. The magnetic effect on ferromagnetic and non-ferromagnetic thermocouples at liquid-nitrogen-boiling point (-196 °C), ice point (0 °C), in water (17 °C) and at melting point of gallium fixed point cell (29.7646 °C) was investigated. Magnetic-field-dependent temperature errors of up to 700 mK (at 5.3 mT: dc) and up to 1 °C (at 10 mT: ac 50 Hz magnetic fields) were detected. From the results, it can be concluded that, ideally for temperature measurements of the highest accuracy in the above-cryogenic temperature range, magnetic sensitivity should be estimated and taken into account either as the correction of an error and/or as an additional source of measurement uncertainty. Special consideration should be given to thermocouple orientation relative to the magnetic field direction, influence of metal enclosures and magnetization effects on ferromagnetic components of thermocouples.

  13. Ocular effects of adrenomedullin.

    PubMed

    Taniguchi, T; Kawase, K; Gu, Z B; Kimura, M; Okano, Y; Kawakami, H; Tsuji, A; Kitazawa, Y

    1999-11-01

    The purpose of this study was to determine the expression and effects of adrenomedullin (AM), a novel vasodilator peptide, in the eye. Expression of AM mRNA was examined in the rat iris-ciliary body using reverse transcription-polymerase chain reaction (RT-PCR). In rabbits, intraocular pressure (IOP) was measured periodically after intravitreal injection (20 microl) of AM (10(-7)-10(-4)m) into one eye. In separate groups of rabbits, 30 min after intravitreal injection of either AM-(22-52) (10(-3)m), a specific AM receptor antagonist, or CGRP-(8-37) (10(-3)m), a CGRP1 receptor antagonist, into one eye, AM (10(-6)m) was injected into both eyes, and IOP was measured. Using different rabbits, aqueous protein and cAMP concentrations were determined 6 hr after injection of AM. Expression of AM mRNA was detected in the rat iris-ciliary body. In rabbits, intravitreally administered AM (10(-6)-10(-4)m) profoundly lowered IOP, and the maximum effect was observed at 4-8 h. The ocular hypotensive effect of AM was dose-dependent (10(-7)-10(-4)m). Pretreatment with CGRP-(8-37) did not significantly inhibit the ocular hypotensive effect of AM (10(-6)m), whereas pretreatment with AM-(22-52) completely abolished it. AM (10(-6)m) did not significantly affect aqueous protein concentration. The higher dose of AM (10(-5)m) induced a significant increase in aqueous protein, which was not associated with an increase in the aqueous cAMP content and was significantly inhibited by AM-(22-52) and CGRP-(8-37). These results demonstrate that AM is expressed in the iris-ciliary body and decreases IOP mainly via specific AM receptors, and suggest that AM may play a role in controlling IOP. PMID:10548466

  14. Dynamical Casimir effect instabilities

    SciTech Connect

    Srivastava, Y. N.; Widom, A.; Ganesh, M. Pradeep; Sivasubramanian, S.

    2006-09-15

    The dynamic Casimir effect, which concerns two photon radiation processes due to time dependent frequency modulations, is computed in the one photon loop approximation. An instability is signaled by the production of an unphysically large number of photons. We show how it is tamed and a saturation in the number of photons reached through higher order processes. Explicit results are obtained for a recently proposed experiment.

  15. The Kaye effect

    NASA Astrophysics Data System (ADS)

    Binder, J. M.; Landig, A. J.

    2009-11-01

    The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for secondary school students. This is our solution to problem number 10, The Kaye effect, as presented in the final round of the 21st IYPT in Trogir, Croatia. The Kaye effect occurs when a thin stream of shampoo or a different adequate non-Newtonian liquid is poured onto a surface. Suddenly, a jet leaves the heap that is formed by the shampoo and begins to 'dance' around the primary jet like a lasso. The phenomenon ends when the 'dancing' jet hits the primary jet and subsequently collapses. We started our investigations based on available literature (Kaye 1963 Nature 197 1001, Versluis et al 2006 J. Stat. Mech., Collyer and Fischer 1976 Nature 261 682). We made experiments with a similar experimental set-up in which we could determine the velocities of both shampoo streams as well as the angle of the 'dancing' stream. From there on, we developed a theoretical model for the energy loss of the jet in the heap. We discovered that the air layer between the jet and the heap is a necessity for the Kaye effect to occur. At this point, our observations differ from the aforementioned literature. This also accounts for the shampoo beam acting as a light guide. Further experiments concerning the viscoelasticity of the shampoo revealed that the elastic property of the shampoo is necessary for the effect to occur. This article is a written version of the oral contribution of the German team to the 21st IYPT competition, which was awarded first prize by an international jury. The article has been edited by European Journal of Physics.

  16. Antidepressant effects of flupenthixol.

    PubMed

    Gruber, A J; Cole, J O

    1991-01-01

    Strong evidence exists that flupenthixol, not presently distributed in the United States, is an effective antidepressant. Its advantages over available antidepressants include its safety with respect to overdose and in combination with other medications, low dependency risk, rapid onset of action, and availability in depot preparation. Flupenthixol also may be useful as a mood elevator for schizophrenics, an alternative mood stabilizer for patients with bipolar disease, and a facilitator for cocaine withdrawal. PMID:1771144

  17. Cardiovascular Effects of Caffeine

    PubMed Central

    Myers, Martin G.

    1992-01-01

    A review of the literature on the cardiovascular effects of caffeine indicates that moderate caffeine consumption does not cause cardiac arrhythmias, hypertension, or an increased incidence of coronary heart disease. Caffeine use is often associated with atherogenic behavior, such as cigarette smoking. Failure to take into account covariables for cardiovascular disease could be responsible for commonly held misconceptions about caffeine and heart disease. PMID:21221403

  18. Transgenerational effects of NMs.

    PubMed

    Poma, Anna; Colafarina, Sabrina; Fontecchio, Gabriella; Chichiriccò, Giuseppe

    2014-01-01

    Nanomaterials are present in a number of commercially available products but there are uncertainties as to whether the unique properties that support their commercial use may also pose potential health risks. Information is missing concerning the influence of nanomaterials on the overall reproductive outcome and transgenerational effects in animals and plants. To obtain this information, long-term studies would be required using animal models phylogenetically close to humans and exposure conditions that reflect realistic scenarios with regard to dosages and admission. The nanoreprotoxicology literature published to date is largely descriptive in nature regarding the effects of nanoparticles. The mechanisms, which determine particle reproduction compatibility, are mostly elusive at the moment. Thus, it is recommended that future research explore the interactions between nanomaterials and transgenerational matter on a molecular level. It would, for instance, be of major importance to understand the behaviour of nanoparticles inside the cells but also their genotoxic and epigenetic effects. Recent studies have shown that intravenous and/or intra-abdominal administration of nanoparticles to mice results in their accumulation in the cells of many tissues, including the brain and the testis, suggesting that they easily pass through the blood-brain and blood-testis barriers. In parallel embryo development after exposure to nanoparticles should be comparatively investigated. The majority of studies on embryo toxicology have concentrated on piscine embryos, mostly derived from zebrafish. Plants for human food as an important component of the ecosystem need also to be taken into account when evaluating transgenerational effects of engineered nanomaterials in crops. PMID:24683035

  19. Ion propulsion cost effectivity

    NASA Technical Reports Server (NTRS)

    Zafran, S.; Biess, J. J.; Callens, R. A.

    1979-01-01

    Ion propulsion modules employing 8 cm thrusters and 30 cm thrusters were studied for Multimission Modular Spacecraft (MMS) applications. Recurring and non-recurring cost elements were generated for these modules. As a result, ion propulsion cost drivers were identified to be Shuttle charges, solar array, power processing, and thruster costs. Cost effective design approaches included short length module configurations, array power sharing, operation at reduced thruster input power (reduced solar array size), simplified power processing units, and power processor output switching.

  20. Ivabradine: cardiovascular effects.

    PubMed

    Rognoni, Andrea; Bertolazzi, Marzia; Macciň, Sergio; Rognoni, Giorgio

    2009-01-01

    Ivabradine (a compound of the benzocyclobutane) is a highly selective I(f) current inhibitor acting directly on the sino-atrial node, induces a rapid, sustained and dose-dependent reduction of heart rate at rest and during exercise without a significant effect on atrio-ventricular conduction, left ventricular contraction/relaxation or vascular tissues. These properties associated with an improvement in left ventricular loading related to bradycardia resulted in an increase in stroke volume and preservation in cardiac output even during exercise. Various experimental and clinical studies showed the efficacy of ivabradine in patients with chronic stable angina, on heart rate reduction, on ventricular remodelling after acute myocardial infarction and on coronary blood flow. The safety of ivabradine has been documented in several studies and clinical trials, in contrast to beta-blockers, no significant side effects were expressed in the literature. The aim of our review is to describe ivabradine and its cardiovascular effects and outline some recent patents and the results of the most important trials. PMID:19149708

  1. Paradoxical Effect of Aspirin

    PubMed Central

    Doutremepuich, Christian; Aguejouf, Omar; Desplat, Vanessa; Eizayaga, Francisco X.

    2012-01-01

    Low-dose aspirin is an important therapeutic option in the secondary prevention of myocardial infarction (MI) and ischemic stroke, basedon its unique cost-effectiveness and widespread availability. In addition, based on the results of a number of large studies, aspirin is also widely used in the primary prevention of MI. This paper provides an update of the available data to offer greater clarity regarding the risks of aspirin with respect to hemorrhagic stroke. In the secondary prevention of cardiovascular, cerebrovascular, and ischemic events, the evidence supports that the benefits of aspirin treatment significantly outweigh the risk of a major hemorrhage. When considering whether aspirin is appropriate, the absolute therapeutic cardiovascular benefits of aspirin must be balanced with the possible risks associated with its use, being hemorrhagic stroke. Regarding these clinical facts, normal, COX 1 ?/?, and COX 2 ?/? mice were treated with a wide range of doses of aspirin and studied by induced hemorrhagic time. The results outlined three major conclusions: high doses of aspirin induce hemorrhage, while low doses of aspirin do not. In the absence of COX 1, ultra low doses of aspirin produce an antihemorrhagic effect not observed with intermediate doses. The absence of COX 2 induced a hemorrhagic effect that needs further research, probably originated in compensatory phenomena. PMID:22292117

  2. Longitudinal Spin Seebeck Effect

    NASA Astrophysics Data System (ADS)

    Uchida, Ken-Ichi

    2013-03-01

    The spin Seebeck effect (SSE) refers to the generation of a spin voltage as a result of a temperature gradient in magnetic materials. Here, a spin voltage is a potential for electron spins to drive a nonequilibrium spin current; when a conductor is attached to a magnet with a finite spin voltage, it induces a spin injection into the conductor. The SSE is of crucial importance in spintronics and spin caloritronics, since it enables simple and versatile generation of a spin current from heat. The simplest and most straightforward setup of the SSE is the longitudinal configuration, in which a spin current flowing parallel to a temperature gradient is measured via the inverse spin Hall effect (ISHE). The longitudinal SSE device consists of a ferromagnetic or ferrimagnetic insulator (FI, e.g. YIG) covered with a paramagnetic metal (PM, e.g. Pt) film. When a temperature gradient is applied perpendicular to the FI/PM interface, an ISHE-induced voltage is generated in the PM layer. In this talk, we report the observation of the longitudinal SSE in various FI/PM systems and provide evidence that the longitudinal SSE is free from thermoelectric artefact, i.e., the anomalous Nernst effect caused by extrinsic magnetic proximity. Then, we discuss the longitudinal SSE from an application point of view. We thank E. Saitoh, S. Maekawa, G. E. W. Bauer, X.-F. Jin, H. Adachi, D. Hou, D. Tian, T. Kikkawa, A. Kirihara, and M. Ishida for their support and valuable discussions.

  3. Planetary Electrochemical Effects

    NASA Astrophysics Data System (ADS)

    Atreya, S. K.; Mihalka, K. M.; Mahaffy, P. R.; Delory, G. T.; Farrell, W. M.

    2008-12-01

    Lightning on a planet other than the Earth was first discovered by Voyager when it flew past Jupiter in 1979. Since then it has been reported on Saturn by Voyager and Cassini, and on Venus from Pioneer Venus and Venus Express. While lightning involves clouds formed from polar molecules such as water, or vulcanism, dusty environments often create electrostatic fields through triboelectric phenomena. In each instance, changes in local chemistry with profound global impact can occur, such as lightning-induced nitrogen fixation on earth. Perhaps the most dramatic effect occurs on Mars within its global dust storms and dust devils. Enhanced production of oxidants, such as hydrogen peroxide, sulfur and halogen species including perhaps perchlorates from minerals in airborne dust are some of the likely chemical effects. The oxidants may be responsible for the lack of organics on the surface of Mars and rapid destruction of methane in the atmosphere. On Titan, the surface organics may be altered by a different (charged particle) effect, a phenomena that may also operate in the polar regions of Mars and on the Galilean satellites. In this talk, we will discuss possible chemical and astrobiological implications of above electrical processes.

  4. Generalized Effective Radiance Temperature

    NASA Astrophysics Data System (ADS)

    Yuan, Z.

    2015-12-01

    Radiance temperature is one of the most important and widely used concepts in radiation thermometry. The usual definition of radiance temperature does not strictly apply for complex situations, such as when surrounding radiation is non-negligible or when corrections are applied to measurements made using an inappropriate emissivity setting. A novel concept, generalized effective radiance temperature (GERT), that adopts a graybody as the reference radiator is proposed in this study to express and explain the actual measurands that exist extensively in practical radiation thermometry applications; for example, a measurement result by a spectral-band radiation thermometer whose instrumental emissivity setting is less than 1. An effective wavelength approach has been developed to elucidate the relationship between a thermometer-dependent temperature (reading from an actual spectral-band radiation thermometer) and the object-side parameter GERT. The characteristics of GERT and the effective wavelength of a GERT measurement are discussed. Choosing an arbitrary emissivity setting to correct for the emissivity of a real target is equivalent to using this value as the emissivity of the reference graybody of the GERT. The GERT can be used in calibrations of both sources and thermometers.

  5. Immunologic effects of yogurt.

    PubMed

    Meydani, S N; Ha, W K

    2000-04-01

    Many investigators have studied the therapeutic and preventive effects of yogurt and lactic acid bacteria, which are commonly used in yogurt production, on diseases such as cancer, infection, gastrointestinal disorders, and asthma. Because the immune system is an important contributor to all of these diseases, an immunostimulatory effect of yogurt has been proposed and investigated by using mainly animal models and, occasionally, human subjects. Although the results of these studies, in general, support the notion that yogurt has immunostimulatory effects, problems with study design, lack of appropriate controls, inappropriate route of administration, sole use of in vitro indicators of the immune response, and short duration of most of the studies limit the interpretation of the results and the conclusions drawn from them. Nevertheless, these studies in toto provide a strong rationale for the hypothesis that increased yogurt consumption, particularly in immunocompromised populations such as the elderly, may enhance the immune response, which would in turn increase resistance to immune-related diseases. This hypothesis, however, needs to be substantiated by well-designed randomized, double-blind, placebo-controlled human studies of an adequate duration in which several in vivo and in vitro indexes of peripheral and gut-associated immune response are tested. PMID:10731490

  6. Generalized Effective Radiance Temperature

    NASA Astrophysics Data System (ADS)

    Yuan, Z.

    2015-10-01

    Radiance temperature is one of the most important and widely used concepts in radiation thermometry. The usual definition of radiance temperature does not strictly apply for complex situations, such as when surrounding radiation is non-negligible or when corrections are applied to measurements made using an inappropriate emissivity setting. A novel concept, generalized effective radiance temperature (GERT), that adopts a graybody as the reference radiator is proposed in this study to express and explain the actual measurands that exist extensively in practical radiation thermometry applications; for example, a measurement result by a spectral-band radiation thermometer whose instrumental emissivity setting is less than 1. An effective wavelength approach has been developed to elucidate the relationship between a thermometer-dependent temperature (reading from an actual spectral-band radiation thermometer) and the object-side parameter GERT. The characteristics of GERT and the effective wavelength of a GERT measurement are discussed. Choosing an arbitrary emissivity setting to correct for the emissivity of a real target is equivalent to using this value as the emissivity of the reference graybody of the GERT. The GERT can be used in calibrations of both sources and thermometers.

  7. Cascading Effects Following Intervention

    PubMed Central

    Patterson, Gerald R.; Forgatch, Marion S.; DeGarmo, David S.

    2010-01-01

    Four different sources for cascade effects were examined using 9-year process and outcome data from a randomized controlled trial (RCT) of a preventive intervention using Parent Management Training – Oregon Model (PMTO™). The social interaction learning (SIL) model of child antisocial behavior serves as one basis for predicting change. A second source addresses the issue of comorbid relationships among clinical diagnoses. The third source, collateral changes, describes events in which changes in one family member correlate with changes in another. The fourth component is based on the long-term effects of reducing coercion and increasing positive interpersonal processes within the family. New findings from the 9-year follow-up show that mothers experienced benefits as measured by standard of living (i.e., income, occupation, education, and financial stress) and frequency of police arrests. It is assumed that PMTO reduces the level of coercion, which sets the stage for a massive increase in positive social interaction. In effect, PMTO alters the family environment and thereby opens doors to healthy new social environments. PMID:20883592

  8. Unintended Effects of Program Evaluation.

    ERIC Educational Resources Information Center

    Welch, Wayne W.; Sternhagen, Fred

    1991-01-01

    Unintended effects of evaluation are discussed, with reference to the Hawthorne Effect, where unintended effects overshadow the manipulations controlled by researchers. Unintended effects are categorized as (1) affective reactions; (2) political dimensions; (3) importance of individual differences; and (4) expectations concerning evaluation.…

  9. SOLAR EFFECTS ON BUILDING DESIGN.

    ERIC Educational Resources Information Center

    Building Research Inst., Inc., Washington, DC.

    A REPORT OF A PROGRAM HELD AS PART OF THE BUILDING RESEARCH INSTITUTE 1962 SPRING CONFERENCE ON THE SOLAR EFFECTS ON BUILDING DESIGN. TOPICS DISCUSSED ARE--(1) SOLAR ENERGY DATA APPLICABLE TO BUILDING DESIGN, (2) THERMAL EFFECTS OF SOLAR RADIATION ON MAN, (3) SOLAR EFFECTS ON ARCHITECTURE, (4) SOLAR EFFECTS ON BUILDING COSTS, (5) SELECTION OF…

  10. Quantum Effects in Biology

    NASA Astrophysics Data System (ADS)

    Mohseni, Masoud; Omar, Yasser; Engel, Gregory S.; Plenio, Martin B.

    2014-08-01

    List of contributors; Preface; Part I. Introduction: 1. Quantum biology: introduction Graham R. Fleming and Gregory D. Scholes; 2. Open quantum system approaches to biological systems Alireza Shabani, Masoud Mohseni, Seogjoo Jang, Akihito Ishizaki, Martin Plenio, Patrick Rebentrost, Alàn Aspuru-Guzik, Jianshu Cao, Seth Lloyd and Robert Silbey; 3. Generalized Förster resonance energy transfer Seogjoo Jang, Hoda Hossein-Nejad and Gregory D. Scholes; 4. Multidimensional electronic spectroscopy Tomáš Mančal; Part II. Quantum Effects in Bacterial Photosynthetic Energy Transfer: 5. Structure, function, and quantum dynamics of pigment protein complexes Ioan Kosztin and Klaus Schulten; 6. Direct observation of quantum coherence Gregory S. Engel; 7. Environment-assisted quantum transport Masoud Mohseni, Alàn Aspuru-Guzik, Patrick Rebentrost, Alireza Shabani, Seth Lloyd, Susana F. Huelga and Martin B. Plenio; Part III. Quantum Effects in Higher Organisms and Applications: 8. Excitation energy transfer in higher plants Elisabet Romero, Vladimir I. Novoderezhkin and Rienk van Grondelle; 9. Electron transfer in proteins Spiros S. Skourtis; 10. A chemical compass for bird navigation Ilia A. Solov'yov, Thorsten Ritz, Klaus Schulten and Peter J. Hore; 11. Quantum biology of retinal Klaus Schulten and Shigehiko Hayashi; 12. Quantum vibrational effects on sense of smell A. M. Stoneham, L. Turin, J. C. Brookes and A. P. Horsfield; 13. A perspective on possible manifestations of entanglement in biological systems Hans J. Briegel and Sandu Popescu; 14. Design and applications of bio-inspired quantum materials Mohan Sarovar, Dörthe M. Eisele and K. Birgitta Whaley; 15. Coherent excitons in carbon nanotubes Leonas Valkunas and Darius Abramavicius; Glossary; References; Index.

  11. The flash grab effect.

    PubMed

    Cavanagh, Patrick; Anstis, Stuart

    2013-10-18

    When an object moves back and forth, its trajectory appears significantly shorter than it actually is. The object appears to stop and reverse well before its actual reversal point, as if there is some averaging of location within a window of about 100 ms (Sinico et al., 2009). Surprisingly, if a bar is flashed at the physical end point of the trajectory, right on top of the object, just as it reverses direction, the flash is also shifted - grabbed by the object - and is seen at the perceived endpoint of the trajectory rather than the physical endpoint. This can shift the perceived location of the flash by as much as 2 or 3 times its physical size and by up to several degrees of visual angle. We first show that the position shift of the flash is generated by the trajectory shortening, as the same shift is seen with or without the flash. The flash itself is only grabbed if it is presented within a small spatiotemporal attraction zone around the physical end point of the trajectory. Any flash falling in that zone is pulled toward the perceived endpoint. The effect scales linearly with speed, up to a maximum, and is independent of the contrast of the moving stimulus once it is above 5%. Finally, we demonstrate that this position shift requires attention. These results reveal a new "flash grab" effect in the family of motion-induced position shifts. Although it most resembles the flash drag effect, it differs from this in the following ways: (1) it has a different temporal profile, (2) it requires attention, (3) it is about 10 times larger. PMID:23872166

  12. 'The Kesterson effect'

    USGS Publications Warehouse

    Presser, T.S.

    1994-01-01

    Hypothesized to be derived from Cretaceous marine sedimentary rocks, selenium contamination of the Kesterson National Wildlife Refuge is traced through irrigation drainage to the source bedrock of the California Coast Ranges. This biogeochemical pathway of selenium is defined here as the 'Kesterson effect.' At the refuge ponds, this effect culminated in 1983 in a 64% rate of deformity and death of embryos and hatchlings of wild aquatic birds. From the previous companion paper on irrigation drainage, the Kesterson effect has been implicated in nine of 11 reconnaissance areas studied in the western United States. Deformities have resulted in at least five of these sites. Climatic, geologic, hydrologic, and soil conditions in these reconnaissance areas are similar to those in the area surrounding Kesterson National Wildlife Refuge in the west-central San Joaquin Valley of California, in California, selenium as selenate, was ultimately found weathered with sulfur from marine sources in soluble sodium and magnesium sulfate salts, which are concentrated by evaporation on farmland soils. The Se, mobilized by irrigation drainage, is bioaccumulated to toxic levels in refuge wetland ponds that are located mainly in hydrologically closed basins and thus act as concentrating disposal points. The depositional environment of the ponds may be similar to that of the nutrient-rich continental shelf edge and slope in which Cretaceous, Eocene, and Miocene sediments found to be seleniferous in the California Coast Ranges were deposited. Bioaccumulation may be therefore a primary mechanism of selenium enrichment in ancient sediments in addition to that of the formerly suggested Cretaceous volcanic pathway.

  13. Environmental Effects of BPA

    PubMed Central

    Canesi, Laura

    2015-01-01

    Research on bisphenol A (BPA) as an environmental contaminant has now major regulatory implications toward the ecosystem health, and hence it is incumbent on scientists to do their research to the highest standards possible, in order that the most appropriate decisions are made to mitigate the impacts to aquatic wildlife. However, the contribution given so far appears rather fragmented. The present overview aims to collect available information on the effects of BPA on aquatic vertebrates and invertebrates to provide a general scenario and to suggest future developments toward more comprehensive approaches useful for aquatic species protection. PMID:26674307

  14. Hepatoprotective effects of mushrooms.

    PubMed

    Soares, Andréia Assunço; de Sá-Nakanishi, Anacharis Babeto; Bracht, Adelar; da Costa, Sandra Maria Gomes; Koehnlein, Eloá Angélica; de Souza, Cristina Giatti Marques; Peralta, Rosane Marina

    2013-01-01

    The particular characteristics of growth and development of mushrooms in nature result in the accumulation of a variety of secondary metabolites such as phenolic compounds, terpenes and steroids and essential cell wall components such as polysaccharides, b-glucans and proteins, several of them with biological activities. The present article outlines and discusses the available information about the protective effects of mushroom extracts against liver damage induced by exogenous compounds. Among mushrooms, Ganoderma lucidum is indubitably the most widely studied species. In this review, however, emphasis was given to studies using other mushrooms, especially those presenting efforts of attributing hepatoprotective activities to specific chemical components usually present in the mushroom extracts. PMID:23884116

  15. Interfacial effects in multilayers

    SciTech Connect

    Barbee, T.W., Jr.

    1998-04-01

    Interfacial structure and the atomic interactions between atoms at interfaces in multilayers or nano-laminates have significant impact on the physical properties of these materials. A technique for the experimental evaluation of interfacial structure and interfacial structure effects is presented and compared to experiment. In this paper the impact of interfacial structure on the performance of x-ray, soft x-ray and extreme ultra-violet multilayer optic structures is emphasized. The paper is concluded with summary of these results and an assessment of their implications relative to multilayer development and the study of buried interfaces in solids in general.

  16. TEACHING PHYSICS: Capillary effects

    NASA Astrophysics Data System (ADS)

    Ivanov, Dragia; Petrova, Hristina

    2000-07-01

    We examine capillary tubes with a variable cross section, in which there is a column of fully wetting or fully non-wetting liquid. The direction in which the liquid moves when the tubes are placed horizontally is determined by means of Pascal's law. We promote the idea that the conical capillary tube is a hydraulic machine, whose two pistons are the liquid column's free surfaces, which have different radii. We propose a new way of demonstrating the described capillary effects by means of flat models of capillary tubes, constructed from glass plates. The demonstrations are presented in front of a large audience using an overhead projector.

  17. Assessments of astronaut effectiveness

    NASA Technical Reports Server (NTRS)

    Rose, Robert M.; Helmreich, Robert L.; Fogg, Louis; Mcfadden, Terry J.

    1993-01-01

    This study examined the reliability and convergent validity of three methods of peer and supervisory ratings of the effectiveness of individual NASA astronauts and their relationships with flight assignments. These two techniques were found to be reliable and relatively convergent. Seniority and a peer-rated Performance and Competence factor proved to be most closely associated with flight assignments, while supervisor ratings and a peer-rated Group Living and Personality factor were found to be unrelated. Results have implications for the selection and training of astronauts.

  18. Microcircuit radiation effects databank

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This databank is the collation of radiation test data submitted by many testers and serves as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. It contains radiation sensitivity results from ground tests and is divided into two sections. Section A lists total dose damage information, and section B lists single event upset cross sections, I.E., the probability of a soft error (bit flip) or of a hard error (latchup).

  19. Assuring reliability program effectiveness.

    NASA Technical Reports Server (NTRS)

    Ball, L. W.

    1973-01-01

    An attempt is made to provide simple identification and description of techniques that have proved to be most useful either in developing a new product or in improving reliability of an established product. The first reliability task is obtaining and organizing parts failure rate data. Other tasks are parts screening, tabulation of general failure rates, preventive maintenance, prediction of new product reliability, and statistical demonstration of achieved reliability. Five principal tasks for improving reliability involve the physics of failure research, derating of internal stresses, control of external stresses, functional redundancy, and failure effects control. A final task is the training and motivation of reliability specialist engineers.

  20. Substantial evidence of effect.

    PubMed

    Gould, A Lawrence

    2002-02-01

    Pressures for rapid drug development, especially for treatments that may affect public health significantly, drive a need to reconsider what is necessary to establish the "substantial evidence" of efficacy and safety required for regulatory approval. The concept of substantial evidence of effect can be stated fairly simply in principle, but its application to the evaluation of findings from real clinical drug development programs can be quite complicated and depend on circumstances relating to the population studied and the condition being treated. This paper discusses a number of considerations that arise in attempting to address this issue. These include confirmation of efficacy/safety as opposed to replication of results, the use of surrogates for the clinical outcome, ethical considerations, the use of trials aimed at demonstrating equivalence or noninferiority instead of superiority of a new drug, and the balance between benefits and risks. Recent developments such as the International Conference on Harmonization (ICH) guidelines dealing with statistical principles and choice of control group, and Food and Drug Administration (FDA) guidances interpreting the 1998 Modernization Act identify useful alternative definitions of substantial evidence and also identify when a single study can be enough to demonstrate a clinically important effect. The primary difficulty with the use of noninferiority trials is the need to demonstrate assay sensitivity or validity, i.e., that the trial would have demonstrated the superiority of the active control treatment to placebo had the trial included a placebo group. Failure to demonstrate a significant difference between the presumed active treatments and an inactive control precludes a definitive conclusion of assay validity, but external evidence, e.g., from trials demonstrating the activity of the active control, may yet justify concluding that the trial was assay valid. Issues of interpretation of important unexpected findings are illustrated in the recent experience with the alpha- and beta-blocker carvedilol, where there was a significant reduction in mortality among patients on carvedilol relative to placebo, but a treatment effect could not be demonstrated for the primary outcome. Experience with trials of thrombolytic agents illustrates alternative strategies for demonstrating substantial evidence of effect. Finally, meta-analyses can contribute to the substantial evidence by synthesizing the findings from separate trials to provide a perspective on drug performance in a heterogeneous population of patients that no single trial could provide. PMID:12146720

  1. [Cognitive effects of opioids].

    PubMed

    Grisart, J

    2009-06-17

    This article discusses the potentially deleterious influence of opioids on cognitive functioning in chronic pain patients. Under stable doses of opioids, cognitive performances in patients are not inferior to those observed in healthy controls. During initialisation and/or adaptation of opioid treatment, a transient inferiority of cognitive performances is observed in chronic pain patients. Studies on combined effects of opioids and psychotropics on cognition are scarce. It is emphasized that cognitive dysfunction in chronic pain patients might be due to the attentional cost due to daily pain. Pain reduction by opioids may diminish this cost. Recommendations for driving under opioids are proposed. PMID:19626760

  2. Radiative Effects of Aerosols

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.

    1997-01-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size resolved aerosol microphysics and chemistry. Both profiles included pollution haze layer from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core.

  3. Ion propulsion cost effectivity

    NASA Technical Reports Server (NTRS)

    Zafran, S.; Biess, J. J.

    1978-01-01

    Ion propulsion modules employing 8-cm thrusters and 30-cm thrusters were studied for Multimission Modular Spacecraft (MMS) applications. Recurring and nonrecurring cost elements were generated for these modules. As a result, ion propulsion cost drivers were identified to be Shuttle charges, solar array, power processing, and thruster costs. Cost effective design approaches included short length module configurations, array power sharing, operation at reduced thruster input power, simplified power processing units, and power processor output switching. The MMS mission model employed indicated that nonrecurring costs have to be shared with other programs unless the mission model grows. Extended performance missions exhibited the greatest benefits when compared with monopropellant hydrazine propulsion.

  4. Flexoelectric effect modelling

    NASA Astrophysics Data System (ADS)

    Kapanowski, A.

    2008-12-01

    A statistical theory of dipole flexoelectric (FE) polarization in liquid crystals is used to calculate temperature dependence of order parameters, elastic constants and FE coefficients. Two systems with polar wedge-shaped and banana-shaped molecules are investigated. In both cases, the FE coefficients are proportional to the dipole moment component parallel to the molecule symmetry axis. It results from the symmetries of interactions and of the Mayer function. The origin of the FE effect and microscopic pictures of the distorted phases are discussed.

  5. Earthquake occurrence and effects.

    PubMed

    Adams, R D

    1990-01-01

    Although earthquakes are mainly concentrated in zones close to boundaries of tectonic plates of the Earth's lithosphere, infrequent events away from the main seismic regions can cause major disasters. The major cause of damage and injury following earthquakes is elastic vibration, rather than fault displacement. This vibration at a particular site will depend not only on the size and distance of the earthquake but also on the local soil conditions. Earthquake prediction is not yet generally fruitful in avoiding earthquake disasters, but much useful planning to reduce earthquake effects can be done by studying the general earthquake hazard in an area, and taking some simple precautions. PMID:2347628

  6. Antiferromagnetic Spin Seebeck Effect.

    PubMed

    Wu, Stephen M; Zhang, Wei; Kc, Amit; Borisov, Pavel; Pearson, John E; Jiang, J Samuel; Lederman, David; Hoffmann, Axel; Bhattacharya, Anand

    2016-03-01

    We report on the observation of the spin Seebeck effect in antiferromagnetic MnF_{2}. A device scale on-chip heater is deposited on a bilayer of MnF_{2} (110) (30  nm)/Pt (4 nm) grown by molecular beam epitaxy on a MgF_{2} (110) substrate. Using Pt as a spin detector layer, it is possible to measure the thermally generated spin current from MnF_{2} through the inverse spin Hall effect. The low temperature (2-80 K) and high magnetic field (up to 140 kOe) regime is explored. A clear spin-flop transition corresponding to the sudden rotation of antiferromagnetic spins out of the easy axis is observed in the spin Seebeck signal when large magnetic fields (>9  T) are applied parallel to the easy axis of the MnF_{2} thin film. When the magnetic field is applied perpendicular to the easy axis, the spin-flop transition is absent, as expected. PMID:26991198

  7. An effective Z'

    DOE PAGESBeta

    Fox, Patrick J.; Liu, Jia; Tucker-Smith, David; Weiner, Neal

    2011-12-06

    We describe a method to couple Z' gauge bosons to the standard model (SM), without charging the SM fields under the U(1)', but instead through effective higher-dimension operators. This method allows complete control over the tree-level couplings of the Z' and does not require altering the structure of any of the SM couplings, nor does it contain anomalies or require introduction of fields in nonstandard SM representations. Moreover, such interactions arise from simple renormalizable extensions of the SM—the addition of vectorlike matter that mixes with SM fermions when the U(1)' is broken. We apply effective Z' models as explanations ofmore » various recent anomalies: the D0 same-sign dimuon asymmetry, the CDF W+di-jet excess and the CDF top forward-backward asymmetry. In the case of the W+di-jet excess we also discuss several complementary analyses that may shed light on the nature of the discrepancy. We consider the possibility of non-Abelian groups, and discuss implications for the phenomenology of dark matter as well.« less

  8. Radiation effects on development.

    PubMed

    De Santis, Marco; Cesari, Elena; Nobili, E; Straface, Gianluca; Cavaliere, Anna Franca; Caruso, Alessandro

    2007-09-01

    It has been widely reported that prenatal exposure to ionizing radiation can interfere with embryonic and fetal development, depending on dose and gestational age in which exposure occurs. According to several studies on animal models, different well-defined stages during prenatal life can be distinguished in relation to teratogenic effects. During the preimplantation stage, elevated doses of radiation can result in abortion, while lower doses may produce genomic damage that is usually repaired. On the other hand, during the organogenesis stage in mice (embryonic day 6.5 [E6.5] to E13.5), irradiation is associated with increased incidence of malformation and intrauterine growth restriction (IUGR). Later exposure is linked to brain damage. Doses used in animal studies are generally higher than those used for diagnostic procedures in humans. Usually, radiation exposure to diagnostic range (<0.05 Gy = 5 rads) is not associated with an increased risk of congenital anomalies. In human studies, elevated doses produce adverse outcomes, depending on stage of development, as in animal studies. Blastogenesis (up to two weeks) is associated with failure to implant or no significant health effects. An increased risk of malformation and growth retardation can be observed for two to seven weeks exposure (organogenesis stage), while exposure at later stages (fetogenesis) is mainly associated with brain damage. In this review we focus on the relevance of estimating the cumulative dose of radiation to the fetus and the gestational age in which exposure occurs, to provide appropriate counseling to pregnant women. PMID:17963274

  9. Lake Effect Clouds

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The lake effect is particularly clear in this Sea-viewing Wide field-of-view Sensor (SeaWiFS) true-color image of the North American Great Lakes region, acquired December 5, 2000. Lakes Nipigon, Superior, and Michigan show striking contrasts between clear and cloudy air as the wind blows from the northwest across the lakes. As it flows across the relatively warm lakes, the cold dry air gathers heat and moisture from the surface. The warm moist air rises into the atmosphere and mixes vigorously with the cold dry air above. The layer of warm moist air deepens as it travels across the lake. Some of the evaporated water from the lake condenses into streamers of fog rising from the surface, while much of the moisture condenses to form a stratocumulus cloud in the upper half of the mixed layer. The cloud-forming water droplets may freeze into ice crystals and, due to accumulated water deposition over time, grow into snowflakes. This process can generate snowstorms that produce significant amounts of snowfall downwind. It is not uncommon for lake effect snowstorms to produce as much as two feet of snow within a 24-hour period in northwestern parts of New York and Pennsylvania. Image provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  10. An effective Z'

    SciTech Connect

    Fox, Patrick J.; Liu, Jia; Tucker-Smith, David; Weiner, Neal

    2011-12-06

    We describe a method to couple Z' gauge bosons to the standard model (SM), without charging the SM fields under the U(1)', but instead through effective higher-dimension operators. This method allows complete control over the tree-level couplings of the Z' and does not require altering the structure of any of the SM couplings, nor does it contain anomalies or require introduction of fields in nonstandard SM representations. Moreover, such interactions arise from simple renormalizable extensions of the SM—the addition of vectorlike matter that mixes with SM fermions when the U(1)' is broken. We apply effective Z' models as explanations of various recent anomalies: the D0 same-sign dimuon asymmetry, the CDF W+di-jet excess and the CDF top forward-backward asymmetry. In the case of the W+di-jet excess we also discuss several complementary analyses that may shed light on the nature of the discrepancy. We consider the possibility of non-Abelian groups, and discuss implications for the phenomenology of dark matter as well.

  11. Microwave field effect transistor

    NASA Technical Reports Server (NTRS)

    Huang, Ho-Chung (inventor)

    1989-01-01

    Electrodes of a high power, microwave field effect transistor are substantially matched to external input and output networks. The field effect transistor includes a metal ground plane layer, a dielectric layer on the ground plane layer, a gallium arsenide active region on the dielectric layer, and substantially coplanar spaced source, gate, and drain electrodes having active segments covering the active region. The active segment of the gate electrode is located between edges of the active segments of the source and drain electrodes. The gate and drain electrodes include inactive pads remote from the active segments. The pads are connected directly to the input and output networks. The source electrode is connected to the ground plane layer. The space between the electrodes and the geometry of the electrodes extablish parasitic shunt capacitances and series inductances that provide substantial matches between the input network and the gate electrode and between the output network and the drain electrode. Many of the devices are connected in parallel and share a common active region, so that each pair of adjacent devices shares the same source electrodes and each pair of adjacent devices shares the same drain electrodes. The gate electrodes for the parallel devices are formed by a continuous stripe that extends between adjacent devices and is connected at different points to the common gate pad.

  12. The Effective Equation Method

    NASA Astrophysics Data System (ADS)

    Kuksin, Sergei; Maiocchi, Alberto

    In this chapter we present a general method of constructing the effective equation which describes the behavior of small-amplitude solutions for a nonlinear PDE in finite volume, provided that the linear part of the equation is a hamiltonian system with a pure imaginary discrete spectrum. The effective equation is obtained by retaining only the resonant terms of the nonlinearity (which may be hamiltonian, or may be not); the assertion that it describes the limiting behavior of small-amplitude solutions is a rigorous mathematical theorem. In particular, the method applies to the three- and four-wave systems. We demonstrate that different possible types of energy transport are covered by this method, depending on whether the set of resonances splits into finite clusters (this happens, e.g. in case of the Charney-Hasegawa-Mima equation), or is connected (this happens, e.g. in the case of the NLS equation if the space-dimension is at least two). For equations of the first type the energy transition to high frequencies does not hold, while for equations of the second type it may take place. Our method applies to various weakly nonlinear wave systems, appearing in plasma, meteorology and oceanography.

  13. Adverse effects of colophony.

    PubMed

    Keira, T; Aizawa, Y; Karube, H; Niituya, M; Shinohara, S; Kuwashima, A; Harada, H; Takata, T

    1997-01-01

    Regarding colophony, the use in industries, adverse effects, diagnosis, pathophysiology and control are reviewed. Colophony is an unhomogeneous mixture of resin acids as like abietic acid and neutral substances. Colophony is used everywhere, in industry, daily life and medical supplies. Soldering workers are exposed to the colophony fumes heated up to the temperature of soldering irons. The effects of exposure to colophony are classified into bronchial asthma and contact dermatitis. Colophony fumes cause bronchial asthma by its nonspecific irritation. Inhalation challenge test and repeated spirometry during working day may help the diagnosis of colophony induced asthma. Improvement of working environment for soldering and development of new flux instead of colophony will be necessary. A study on contact dermatitis revealed that colophony and its related compounds are one of major causes for contact dermatitis. Cases of dermatitis by depilatory agents used to remove hair from slaughtered swine, anti-slipping cream for ballet shoes or resin for cello strings have been reported. Patch test may contribute to the diagnosis of dermatitis caused by colophony. PMID:9009495

  14. Antiferromagnetic Spin Seebeck Effect

    NASA Astrophysics Data System (ADS)

    Wu, Stephen M.; Zhang, Wei; KC, Amit; Borisov, Pavel; Pearson, John E.; Jiang, J. Samuel; Lederman, David; Hoffmann, Axel; Bhattacharya, Anand

    2016-03-01

    We report on the observation of the spin Seebeck effect in antiferromagnetic MnF2 . A device scale on-chip heater is deposited on a bilayer of MnF2 (110) (30 nm )/Pt (4 nm) grown by molecular beam epitaxy on a MgF2 (110) substrate. Using Pt as a spin detector layer, it is possible to measure the thermally generated spin current from MnF2 through the inverse spin Hall effect. The low temperature (2-80 K) and high magnetic field (up to 140 kOe) regime is explored. A clear spin-flop transition corresponding to the sudden rotation of antiferromagnetic spins out of the easy axis is observed in the spin Seebeck signal when large magnetic fields (>9 T ) are applied parallel to the easy axis of the MnF2 thin film. When the magnetic field is applied perpendicular to the easy axis, the spin-flop transition is absent, as expected.

  15. Effects of acoustic sources

    NASA Astrophysics Data System (ADS)

    Schoenster, James A.; Jones, Michael G.

    1987-12-01

    An experiment was conducted to determine the effect of acoustics on the laminar flow on the side of a nacelle. A flight test was designed to meet this goal and a brief review of the purpose is given. A nacelle with a significant length of laminar flow was mounted on the wing of NASA OV-1. Two noise sources are also mounted on the wing: one in the center body of the nacelle; the second in a wing mounted pod outboard of the nacelle. These two noise sources allow for a limited study of the effect of source direction in addition to control of the acoustic level and frequency. To determine the range of Tollmien-Schlichting frequencies, a stability analysis using the pressure coefficient distribution along the side of the nacelle was performed. Then by applying these frequencies and varying the acoustic level, a study of the receptivity of the boundary layer to the acoustic signal, as determined by the shortening of the length of laminar flow, was conducted. Results are briefly discussed.

  16. Strategies for effective feedback.

    PubMed

    Kritek, Patricia A

    2015-04-01

    Provision of regular feedback to trainees on clinical performance by supervising providers is increasingly recognized as an essential component of undergraduate and graduate health sciences education; however, many individuals have not been formally trained in this pedagogical skill. At the bedside or in the clinic, effective performance feedback can be accomplished by following four key steps. Begin by setting expectations that incorporate the trainee's personal goals and external objectives. Delineate how and when you will provide feedback to the learner. Next, directly observe the trainee's performance. This can be challenging while engaged on a busy clinical service, but a focus on discrete activities or interactions (e.g., family meeting, intravascular volume assessment using bedside ultrasound, or obtaining informed consent) is helpful. The third step is to plan and prioritize the feedback session. Feedback is most effective when given in a timely fashion and delivered in a safe environment. Limit the issues addressed because learners often disengage if confronted with too many deficiencies. Finally, when delivering feedback, begin by listening to the trainee's self-evaluation and then take a balanced approach. Describe in detail what the trainee does well and discuss opportunities for improvement with emphasis on specific, modifiable behaviors. The feedback loop is completed with a plan for follow-up reassessment. Through the use of these relatively simple practices, both the trainee and teacher can have a more productive learning experience. PMID:25723379

  17. Ecotoxicological effects extrapolation models

    SciTech Connect

    Suter, G.W. II

    1996-09-01

    One of the central problems of ecological risk assessment is modeling the relationship between test endpoints (numerical summaries of the results of toxicity tests) and assessment endpoints (formal expressions of the properties of the environment that are to be protected). For example, one may wish to estimate the reduction in species richness of fishes in a stream reach exposed to an effluent and have only a fathead minnow 96 hr LC50 as an effects metric. The problem is to extrapolate from what is known (the fathead minnow LC50) to what matters to the decision maker, the loss of fish species. Models used for this purpose may be termed Effects Extrapolation Models (EEMs) or Activity-Activity Relationships (AARs), by analogy to Structure-Activity Relationships (SARs). These models have been previously reviewed in Ch. 7 and 9 of and by an OECD workshop. This paper updates those reviews and attempts to further clarify the issues involved in the development and use of EEMs. Although there is some overlap, this paper does not repeat those reviews and the reader is referred to the previous reviews for a more complete historical perspective, and for treatment of additional extrapolation issues.

  18. Antidepressant effect of Stillen.

    PubMed

    Jeong, Hyun-Ja; Kim, Jeong-Hwa; Kim, Na-Rae; Yoou, Myoung-schook; Nam, Sun-Young; Kim, Kyu-Youb; Choi, Youngjin; Jang, Jae-Bum; Kang, In-Cheol; Baek, Nam-In; Kim, Hyung-Min

    2015-06-01

    Stillen has been used to treat patients with gastric mucosal ulcers and has an anti-inflammatory effect. It is well-known that neuro-inflammatory reactions are related to depression. Here we evaluated the antidepressant-like effect of Stillen on mice subjected to the forced swimming test (FST). Stillen and eupatilin (a major component of Stillen) significantly decreased immobility times compared with the FST control group. In the Stillen-administered group, increased levels of 5-hydroxytryptamine (serotonin) and brain-derived neurotrophic factor protein were observed in the hippocampus. Nissl bodies also increased in the hippocampus neuronal cytoplasm of the Stillen-administered group. Stillen decreased levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (at the mRNA and protein levels) in the hippocampus and serum, compared with the control group. In addition, the mRNA expression of estrogen receptor-β increased after Stillen administration in the hippocampus. These findings suggest that Stillen should be viewed as a candidate antidepressant. PMID:25163682

  19. The effective MSSM

    NASA Astrophysics Data System (ADS)

    Kobakhidze, Archil; Talia, Matthew

    2015-12-01

    We suggest an effective field theory framework to discuss deviations from the minimal supersymmetric Standard Model (MSSM) which is based on an alternative arrangement of the gauge-Higgs sector. In this effective MSSM (EffMSSM) nonlinearly realised SU (2) × U (1) gauge sector is described by an SU (2) × U (1)-valued massive vector superfield, which contains a neutral CP-even and charged Higgs fields, while another neutral CP-even Higgs and the neutral CP-odd Higgs fields are residing in an SU (2) × U (1)-singlet chiral superfield. Although the new theory contains the same particle content as the conventional MSSM, the unconventional representation of superfields allows for new type of interactions, which may lead to a significant modification of the phenomenology. As an illustrative example we consider EffMSSM with modified Higgs and electroweak gauge sector augmented by gaugino soft supersymmetry breaking masses, Mi (i = 1 , 2 , 3) and the Standard Higgs soft-breaking masses, mHu =mHd and B?, and point out distinct features in the Higgs and gaugino sectors as compared to MSSM. In particular, we show that the lightest neutral CP-even Higgs boson with mass ? 125GeV can be easily accommodated within EffMSSM.

  20. Behavioral effects of microwaves

    SciTech Connect

    Stern, S.

    1980-01-01

    Microwaves can produce sensations of warmth and sound in humans. In other species, they also can serve as cues, they may be avoided, and they can disrupt ongoing behavior. These actions appear to be due to heat produced by energy absorption. The rate of absorption depends on the microwave parameters and the electrical and geometric properties of the subject. We therefore, cannot predict the human response to microwaves based on data from other animals without appropriate scaling considerations. At low levels of exposure, microwaves can produce changes in behavior without large, or even measureable, changes in body temperature. Thermoregulatory behavior may respond to those low levels of heat, and thereby affect other behavior occurring concurrently. There are no data that demonstrate that behavioral effects of microwaves depend on any mechanism other than reactions to heat. Our interpretation of whether a reported behavioral effect indicates that microwaves may be hazardous depends on our having a complete description of the experiment and on our criteria of behavioral toxicity.

  1. Acrolein health effects.

    PubMed

    Faroon, O; Roney, N; Taylor, J; Ashizawa, A; Lumpkin, M H; Plewak, D J

    2008-08-01

    Acrolein is a chemical used as an intermediate reactive aldehyde in chemical industry. It is used for synthesis of many organic substances, methionine production, and methyl chloride refrigerant. The general population is exposed to acrolein via smoking, second-hand smoke, exposure to wood and plastic smoke. Firefighters and population living or working in areas with heavy automotive traffic may expose to higher level of acrolein via inhalation of smoke or automotive exhaust. Degradation of acrolein in all environmental media occurs rapidly, therefore, environmental accumulation is not expected. Acrolein degrade in 6A days when applied to surface water, and it has not been found as a contaminant in municipal drinking water. Acrolein vapor may cause eye, nasal and respiratory tract irritations in low level exposure. A decrease in breathing rate was reported by volunteers acutely exposed to 0.3A ppm of acrolein. At similar level, mild nasal epithelial dysplasia, necrosis, and focal basal cell metaplasia have been observed in rats. The acrolein effects on gastrointestinal mucosa in the animals include epithelial hyperplasia, ulceration, and hemorrhage. The severity of the effects is dose dependent. Acrolein induces the respiratory, ocular, and gastrointestinal irritations by inducing the release of peptides in nerve terminals innervating these systems. Levels of acrolein between 22 and 249 ppm for 10 min induced a dose-related decrease in substance P (a short-chain polypeptide that functions as a neurotransmitter or neuromodulator). PMID:19028774

  2. The Creative Stereotype Effect

    PubMed Central

    Dumas, Denis; Dunbar, Kevin N.

    2016-01-01

    Because of its fundamental relevance to scientific innovation, artistic expression, and human ingenuity, creativity has long been the subject of systematic psychological investigation. Concomitantly, the far-reaching effects of stereotypes on various cognitive and social processes have been widely researched. Bridging these two literatures, we show in a series of two studies that stereotypes related to creativity can both enhance and diminish individuals’ performance on a divergent thinking task. Specifically, Study 1 demonstrated that participants asked to take on a stereotypically uninhibited perspective performed significantly better on a divergent thinking task than those participants who took on a stereotypically inhibited perspective, and a control group. Relatedly, Study 2 showed that the same effect is found within-subjects, with divergent thinking significantly improving when participants invoke an uninhibited stereotype. Moreover, we demonstrate the efficacy of Latent Semantic Analysis as an objective measure of the originality of ideas, and discuss implications of our findings for the nature of creativity. Namely, that creativity may not be best described as a stable individual trait, but as a malleable product of context and perspective. PMID:26863143

  3. [Is the analgesic effect of acupuncture a placebo effect?].

    PubMed

    Musial, F; Tao, I; Dobos, G

    2009-08-01

    The German acupuncture trials ART and GERAC have shown that acupuncture and sham or minimal acupuncture were equally effective in the reduction of chronic pain symptoms. These results have prompted an ongoing discussion as to whether acupuncture exerts its effects through a placebo response. Increasing knowledge about the neurobiology of pain and its intrinsic control suggests a combination of acupuncture-specific neurophysiologic effects combined with effects that match those of expectation-induced placebo analgesia. PMID:19557440

  4. Effect Sizes, Confidence Intervals, and Confidence Intervals for Effect Sizes

    ERIC Educational Resources Information Center

    Thompson, Bruce

    2007-01-01

    The present article provides a primer on (a) effect sizes, (b) confidence intervals, and (c) confidence intervals for effect sizes. Additionally, various admonitions for reformed statistical practice are presented. For example, a very important implication of the realization that there are dozens of effect size statistics is that "authors must…

  5. TOWARD MORE EFFECTIVE REGULATION

    SciTech Connect

    J. GRAF

    2000-06-01

    This paper proposes a model relationship between the operator engaged in a hazardous activity, the regulator of that activity, and the general public. The roles and responsibilities of each entity are described in a way that allows effective communication flow. The role of the regulator is developed using the steam boiler as an example of a hazard subject to regulation; however, the model applies to any regulated activity. In this model the safety analyst has the extremely important role of communicating sometimes difficult technical information to the regulator in a way that the regulator can provide credible assurance to the general public as to the adequacy of the control of the hazardous activity. The conclusion asserts that acceptance of the model, understanding of the roles and responsibilities and definition of who communicates what information to whom will mitigate frustration on the part of each of the three entities.

  6. Magnetically assisted Sisyphus effect

    NASA Astrophysics Data System (ADS)

    Emile, Olivier; Kaiser, Robin; Gerz, Christoph; Wallis, Hartmut; Aspect, Alain; Cohen-Tannoudji, Claude

    1993-12-01

    This paper presents an experimental and theoretical study of laser cooling in a standing wave in the presence of a small transverse magnetic field (Magnetically Assisted Sisyphus Effect: MASE). The analysis is worked out for a J_g=1 to J_e=1 transition corresponding to the experiment performed on the 23S1longleftrightarrow 23P1 transition of metastable helium. In this situation, MASE has an effect opposed to the usual Doppler cooling effect, i.e. it produces heating for a negative detuning. Depending on the various parameters, the competition between MASE and Doppler cooling, which act on different velocity ranges, leads to interesting new effects, such as a bistable force. The velocity dependence of the total force is calculated, using a semi-classical approach. A second theoretical treatment, where the atomic motion is quantized, is used to study the time evolution of the velocity distribution. The results of these calculations are compared to experimental observations. Cet article présente une étude expérimentale et théorique du refroidissement laser par une onde stationnaire quasi-résonnante en présence d'un champ magnétique transverse faible (Effet Sisyphe Magnétique). Les calculs théoriques ont été développés sur une transition J_g=1to J_e=1 correspondant à la situation expérimentale que nous avons étudiée sur la transition 23S1longleftrightarrow 23P1 de l'hélium métastable. Dans ce cas, l'effet Sisyphe magnétique a une action opposée à celle du refroidissement Doppler habituel : il produit un chauffage pour un accord du laser en dessous de résonance. La compétition entre l'effet Sisyphe magnétique et le refroidissement Doppler, qui agissent sur des gammes de vitesse différentes, débouche sur de nouveaux effets intéressants, et notamment sur une force présentant un caractère bistable. Nous avons calculé la force totale en fonction de la vitesse en utilisant une approche semi-classique. Nous avons aussi utilisé une seconde approche théorique où l'impulsion atomique est quantifiée, et qui permet d'étudier d'évolution temporelle de la distribution en vitesse. Les résultats théoriques sont ensuite confrontés aux résultats expérimentaux.

  7. Biological effects of ozone

    SciTech Connect

    Lippmann, M. )

    1989-09-01

    Tropospheric ozone, a classic anthropogenic air pollutant, is going to remain a troublesome byproduct of contemporary civilization for many decades. We have known for some time that the hydrocarbons and nitrogen oxides from motor vehicles, together with actinic radiation, account for local and regional photochemistry leading to prolonged afternoon ozone peaks. We also now know that agricultural burning and intensive animal husbandry elevate regional and mesoscale concentrations of ozone and its precursors, and that remote background levels of ozone have been rising steadily throughout this century. The changes we will have to make in emission controls to appreciably reduce current tropospheric ozone levels will have profound effects on our transportation systems, consumer products, and lifestyles. As a society, we will have to make difficult choices about the levels of ozone-associated health, welfare, and natural system damage we will tolerate, or conversely, how much we are willing to pay for controls which can minimize the damage.

  8. Hot chocolate effect

    SciTech Connect

    Crawford, F.S.

    1982-05-01

    The ''hot chocolate effect'' was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one-quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the 10% accuracy of the experiments.

  9. THE HOT CHOCOLATE EFFECT

    SciTech Connect

    Crawford, Frank S.

    1980-12-01

    The "hot chocolate effect" was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the ten percent accuracy of the experiments.

  10. Nutritional effects on sleep.

    PubMed

    Lindseth, Glenda; Lindseth, Paul; Thompson, Mark

    2013-04-01

    The purpose of this study was to examine the nutritional effects on sleep using actigraphy measures. A repeated-measures, counterbalanced, crossover study design was used to administer treatment diets to 44 adult participants. Participants served as their own control and consumed high-protein, high-fat, high-carbohydrate, and control diets. The study participants wore Motionlogger Actigraph sleep watches while consuming weighed food intakes for 4 days over four different treatment periods. Demographic and laboratory data were also analyzed. Actigraph results showed that the wake episodes and sleep latencies were significantly different when comparing the macronutrient intakes of the participants. Post hoc test results showed that high-protein diets were associated with significantly fewer (p = .03) wake episodes and high-carbohydrate diets were associated with significantly shorter (p < .01) sleep latencies than control diets. Thus, consumption of specific macronutrient intakes may have a significant influence on sleep. PMID:21816963

  11. Hydrodynamic effects on coalescence.

    SciTech Connect

    Dimiduk, Thomas G.; Bourdon, Christopher Jay; Grillet, Anne Mary; Baer, Thomas A.; de Boer, Maarten Pieter; Loewenberg, Michael; Gorby, Allen D.; Brooks, Carlton, F.

    2006-10-01

    The goal of this project was to design, build and test novel diagnostics to probe the effect of hydrodynamic forces on coalescence dynamics. Our investigation focused on how a drop coalesces onto a flat surface which is analogous to two drops coalescing, but more amenable to precise experimental measurements. We designed and built a flow cell to create an axisymmetric compression flow which brings a drop onto a flat surface. A computer-controlled system manipulates the flow to steer the drop and maintain a symmetric flow. Particle image velocimetry was performed to confirm that the control system was delivering a well conditioned flow. To examine the dynamics of the coalescence, we implemented an interferometry capability to measure the drainage of the thin film between the drop and the surface during the coalescence process. A semi-automated analysis routine was developed which converts the dynamic interferogram series into drop shape evolution data.

  12. The hot chocolate effect

    NASA Astrophysics Data System (ADS)

    Crawford, Frank S.

    1982-05-01

    The ''hot chocolate effect'' was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one-quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the 10% accuracy of the experiments.

  13. [Side effects of caffeine].

    PubMed

    Dworzański, Wojciech; Opielak, Grzegorz; Burdan, Franciszek

    2009-11-01

    Caffeine is one of the most commonly ingested alkaloids worldwide. It is present in coffee, tea, soft and energy drinks, chocolate, etc. Currently published data has been stressed that the metyloxantine consumption increases the risk of coronary heart disease, arterial hypertension, arterial stiffness, and an elevation of cholesterol and homocysteine plasma concentration. The acute high consumption may also modulate insulin sensitivity and glucose blood level. However, the long-term consumption reduces the incidence of the type 2 diabetes mellitus. When administered in high doses the substance may cause various side effects, related to abnormal stimulation of the central nervous system, decrease tonus of the lower esophageal sphincter, as well as increase risk of miscarriage and intrauterine growth retardation. The final manifestation of side reactions is dependent on the genotype, especially polymorphisms of genes associated with caffeine metabolism, i.e., cytochrome P450-CYP1A2 and catechol-O-methyltransferase (COMT). PMID:19999796

  14. Fractional quantized Hall effect

    SciTech Connect

    Tsui, D.C. . Dept. of Electrical Engineering and Computer Science)

    1991-06-01

    This paper gives an overview of experiments on the fractional quantized Hall effect (FQHE). Two recent developments are discussed in some detail. One is the investigation of resistance fluctuations in narrow samples which gives evidence that the charge carried by a quasiparticle/quasihole excitation of the 1/3 FQH liquid is e/3. The other is on the influence of disorder in the two-dimensional electron system on the 1.5 FQH liquid and the re-entrant nature of the insulating state below and above it. The more recent observation, in this re-entrant insulating state, of an electric field induced transition into an {gt} 10 times more conducting state, accompanied by an onset of low frequency noise, is reviewed. It is confirmation that in low disorder samples the insulating and nonlinear transport characteristics around filling factor {nu} = 1.5 are indicative of a transition from the incompressible FQH liquids to a deformable Wigner solid.

  15. Radiation Effects In Space

    SciTech Connect

    Tripathi, Ram K.

    2011-06-01

    Protecting space missions from severe exposures from radiation, in general, and long duration/deep space human missions, in particular, is a critical design driver, and could be a limiting factor. The space radiation environment consists of galactic cosmic rays (GCR), solar particle events (SPE), trapped radiation, and includes ions of all the known elements over a very broad energy range. These ions penetrate spacecraft materials producing nuclear fragments and secondary particles that damage biological tissues and microelectronic devices. One is required to know how every element (and all isotopes of each element) in the periodic table interacts and fragments on every other element in the same table as a function of kinetic energy ranging over many decades. In addition, the accuracy of the input information and database, in general and nuclear data in particular, impacts radiation exposure health assessments and payload penalty. After a brief review of effects of space radiation on materials and electronics, human space missions to Mars is discussed.

  16. Thermosensory reversal effect quantified.

    PubMed

    Bergmann Tiest, Wouter M; Kappers, Astrid M L

    2008-01-01

    At room temperature, some materials feel colder than others due to differences in thermal conductivity, heat capacity and geometry. When the ambient temperature is well above skin temperature, the roles of 'cold' and 'warm' materials are reversed. In this paper, this effect is quantified by measuring discrimination thresholds for subjective coldness at different ambient temperatures using stimuli of different thicknesses. The reversal point was found to be at 34 degrees C, somewhat above skin temperature. At this reversal point, discrimination is quite impossible. At room temperature, subjects were able to discriminate between stimuli of different thickness based on subjective coldness, showing that the sense of touch, unlike vision, can penetrate solid objects. Furthermore, somewhat surprisingly, at ambient temperatures well below normal room temperature, discrimination is worse than at room temperature. PMID:17306203

  17. Action languages: Dimensions, effects

    NASA Technical Reports Server (NTRS)

    Hayes, Daniel G.; Streeter, Gordon

    1989-01-01

    Dimensions of action languages are discussed for communication between humans and machines, and the message handling capabilities of object oriented programming systems are examined. Design of action languages is seen to be very contextual. Economical and effective design will depend on features of situations, the tasks intended to be accomplished, and the nature of the devices themselves. Current object oriented systems turn out to have fairly simple and straightforward message handling facilities, which in themselves do little to buffer action or even in some cases to handle competing messages. Even so, it is possible to program a certain amount of discretion about how they react to messages. Such thoughtfulness and perhaps relative autonomy of program modules seems prerequisite to future systems to handle complex interactions in changing situations.

  18. Radiative Effects of Aerosols

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.

    1996-01-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size-resolved aerosol microphysics and chemistry. Both profiles included a pollution haze from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core. The soot core increased the calculated extinction by about 10% in the most polluted drier layer relative to a pure sulfate aerosol but had significantly less effect at higher humidities. A 3 km descent through a boundary layer air mass dominated by pollutant aerosol with relative humidities (RH) 10-77% yielded a close agreement between the measured and calculated aerosol optical depths (550 nm) of 0.160 (+/- 0.07) and 0. 157 (+/- 0.034) respectively. During descent the aerosol mass scattering coefficient per unit sulfate mass varied from about 5 to 16 m(exp 2)/g and primarily dependent upon ambient RH. However, the total scattering coefficient per total fine mass was far less variable at about 4+/- 0.7 m(exp 2)/g. A subsequent descent through a Saharan dust layer located above the pollution aerosol layer revealed that both layers contributed similarly to aerosol optical depth. The scattering per unit mass of the coarse aged dust was estimated at 1.1 +/- 0.2 m(exp 2)/g. The large difference (50%) in measured and calculated optical depth for the dust layer exceeded measurements.

  19. The EMC effect

    NASA Astrophysics Data System (ADS)

    Barone, V.; Predazzi, E.

    Origin, development and present status of the so-called EMC effect, i.e. the experimental finding that the nucleon structure function is different for bound and free nucleons are reviewed in some detail after a brief introduction to the formalism of deep inelastic scattering appropriate to treat this problem. Some of the theoretical ideas that have been put forward in this context are then presented in an effort to compare them and to show how apparently different views to the same problem can lead to similar results. The compatibility of some of these different approaches is also briefly addressed to in the hope that the EMC effect may provide the key to the code to translate between the language of conventional nuclear physics and the one describing the nucleus in terms of quark degrees of freedom. L'origine, le développement et l'état actuel de l'effet appelé « EMC », c'est-ŕ-dire la découverte que la fonction de structure des nucléons est différente selon que ces nucléons sont liés ou non, sont passés en revue en détail aprčs quelques rappels sur le formalisme de la diffusion profondément inélastique, qui constitue le cadre théorique approprié pour traiter ce problčme. Les principales idées théoriques qui ont été mises en avant dans ce contexte sont présentées d'une façon qui s'attache ŕ les comparer aussi directement que possible, et en dégageant les raisons qui font que des points de vue apparemment trčs différents sur ce problčme peuvent mener ŕ des résultats semblables. La compatibilité de quelques-unes de ces diverses approches est également discutée dans l'espoir que l'effet EMC puisse procurer un code ou un dictionnaire pour passer du langage de la physique nucléaire traditionnelle ŕ celui oů l'on décrit le noyau en termes de degrés de liberté de quarks.

  20. Two impurity Kondo effect

    NASA Astrophysics Data System (ADS)

    Lai, Yu-Ren; Wang, Da-Wei; Lin, Juhn-Jong

    2014-03-01

    We have fabricated a series of Al/AlOx/Y tunnel junctions and measured the differential conductance G(V , T) down to 0 . 25 K. We found that the zero-bias conductance G(0 , T) increases with reducing T below ~ 40 K, i.e., G(0 , T) obeys a - lnT law in a higher T regime (~ 10 - 25 K) and crosses over to a -?{ T} law in an intermediate T regime (~ 5 - 20 K). The unique -?{ T} feature is suggestive of a novel Kondo effect. In particular, in this intermediate T regime, we observed that the finite-bias G(V , T) curves at different T's collapse closely and can be described by [ G(0 , T) - G(V , T) ] / ?{ T} = f(?{ eV /kB T }) , where f is a universal scaling function characteristic of the two-impurity Kondo effect. We have further varied the barrier properties in a series of samples. We found three kinds of T dependence for G(0 , T) at T < 4 K. The first kind, G(0 , T) saturates as T --> 0 K. The second kind, G(0 , T) passes over a maximum and then decreases with reducing T. The third kind, G(0 , T) keeps increasing down to 0.25 K. We ascribe the three kinds of samples to possess distinct ground states: the Kondo screened state, the RKKY singlet state, and the one around the quantum critical point. This work was supported by the Taiwan National Science Council through Grant Nos. NSC 102-2120-M-009-003 and the MOE ATU Program (J.J.L.).

  1. Managing Chemotherapy Side Effects: Infection

    MedlinePLUS

    ... ational C ancer I nstitute Managing Chemotherapy Side Effects Infection “I am extra careful to stay away ... doctor or nurse right away. Managing Chemotherapy Side Effects: Infection Take these steps to lower your chances ...

  2. Managing Chemotherapy Side Effects: Diarrhea

    MedlinePLUS

    ... ational C ancer I nstitute Managing Chemotherapy Side Effects U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES National ... before taking medicine for diarrhea. Managing Chemotherapy Side Effects: Diarrhea These foods and drinks may help if ...

  3. Managing Chemotherapy Side Effects: Anemia

    MedlinePLUS

    ... ational C ancer I nstitute Managing Chemotherapy Side Effects Anemia “I told my doctor that I was ... exercise a little every day. Managing Chemotherapy Side Effects: Anemia Eat and drink well. ● ● Talk with your ...

  4. Hall Effect in a Plasma.

    ERIC Educational Resources Information Center

    Kunkel, W. B.

    1981-01-01

    Describes an apparatus and procedure for conducting an undergraduate laboratory experiment to quantitatively study the Hall effect in a plasma. Includes background information on the Hall effect and rationale for conducting the experiment. (JN)

  5. Union Effects on Teacher Productivity.

    ERIC Educational Resources Information Center

    Eberts, Randall W.

    1984-01-01

    This paper examines the effect of collective bargaining on several factors known to be determinants of student achievement in the public schools, particularly its effect on the teacher's allocation of time among various activities. (Author/SSH)

  6. Flight effects of fan noise

    NASA Technical Reports Server (NTRS)

    Chestnutt, D. (Editor)

    1982-01-01

    Simulation of inflight fan noise and flight effects was discussed. The status of the overall program on the flight effects of fan noise was reviewed, and flight to static noise comparisons with the JT15D engine were displayed.

  7. Side Effects of Hormone Therapy

    MedlinePLUS

    ... Up Care Back to Side Effects English | Español Testosterone is the primary male hormone, and plays an ... the body. The list of potential effects of testosterone loss is long: hot flashes, decreased sexual desire, ...

  8. Dispersant effectiveness: Studies into the causes of effectiveness variations

    SciTech Connect

    Fingas, M.F.; Kyle, D.; Tennyson, E.

    1995-06-01

    Effectiveness, a key issue of using dispersants, is affected by many interrelated factors. The principal factors involved are the oil composition, dispersant formulation, sea surface turbulence and dispersant quantity. Oil composition is a very strong determinant. Current dispersant formulation effectiveness correlates strongly with the amount of saturate component in the oil. The other components of the oil, the asphaltenes, resins or polars and aromatic fractions show a negative correlation with the dispersant effectiveness. Viscosity is also a predictor of dispersant effectiveness and may have an effect because it is in turn determined by oil composition. Dispersant composition is significant and interacts with oil composition. Dispersants show high effectiveness at HLB values near 10. Sea turbulence strongly affects dispersant effectiveness.Effectiveness rises with increasing turbulence to a maximum value. Effectiveness for current commercial dispersants is gaussian around a peak salinity value. Peak effectiveness is achieved at very high dispersant quantities--at a ratio of 1:5, dispersant-to-oil volume. Dispersant effectiveness for those oils tested and under the conditions measured, is approximately logarithmic with dispersant quantity and will reach about 50% of its peak value at a dispersant to oil ratio of about 1:20 and near zero at a ratio of about 1:50.

  9. Radiation effect on implanted pacemakers

    SciTech Connect

    Pourhamidi, A.H.

    1983-10-01

    It was previously thought that diagnostic or therapeutic ionizing radiation did not have an adverse effect on the function of cardiac pacemakers. Recently, however, some authors have reported damaging effect of therapeutic radiation on cardiac pulse generators. An analysis of a recently-extracted pacemaker documented the effect of radiation on the pacemaker pulse generator.

  10. "No Effects" Studies Raising Eyebrows

    ERIC Educational Resources Information Center

    Viadero, Debra

    2009-01-01

    Like a steady drip from a leaky faucet, the experimental studies being released this school year by the federal Institute of Education Sciences are mostly producing the same results: "No effects," "No effects," "No effects." The disappointing yield is prompting researchers, product developers, and other experts to question the design of the…

  11. Cognitive Constraints and Island Effects

    ERIC Educational Resources Information Center

    Hofmeister, Philip; Sag, Ivan A.

    2010-01-01

    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that…

  12. Assessing and Improving Institutional Effectiveness.

    ERIC Educational Resources Information Center

    Cameron, Kim S.

    Information to promote assessment of organizational effectiveness in colleges and universities is presented, along with an exercise to rank the effectiveness of 10 institutions. The exercise uses three types of criteria to indicate effectiveness: subjective ratings, data about students and activities, and institutional capacity and financial…

  13. Cognitive Constraints and Island Effects

    ERIC Educational Resources Information Center

    Hofmeister, Philip; Sag, Ivan A.

    2010-01-01

    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that…

  14. Effective Management of Contract Activities.

    ERIC Educational Resources Information Center

    Clark, Donald L.

    Securing funds to support a project does not necessarily guarantee its success. For any venture to be successful it must be undergirded by an effective management system. Discussed are four basic questions on the topic of effective project management. (1) When should project management start? (2) Who is responsible for the effective management…

  15. Effective Programs for Latino Students.

    ERIC Educational Resources Information Center

    Slavin, Robert E., Ed.; Calderon, Margarita, Ed.

    This collection of papers presents the current state of research on effective instructional programs for Hispanic American students. The 10 chapters are: (1) "Effective Programs for Latino Students in Elementary and Middle Schools" (Olatokunbo S. Fashola, Robert E. Slavin, Margarita Calderon, and Richard Duran); (2) "Effective Dropout Prevention…

  16. PEPNet Effective Practices Criteria Workbook.

    ERIC Educational Resources Information Center

    O'Sullivan, Kate, Ed.

    Designed for youth programs, funders, policymakers, and researchers, this workbook is a tool and a resource on effective practices for youth employment and development. It is a product of the Promising and Effective Practices Network (PEPNet), which offers a knowledge base of effective strategies and approaches, opportunities for professional…

  17. Effects Of Radiation On Elastomers

    NASA Technical Reports Server (NTRS)

    Bouquet, Frank L.

    1988-01-01

    Report provides data on effects of radiation on elastomers. Quantifies effects by giving minimum radiation levels to induce changes of 1 percent and 25 percent in given properties. Electrical, mechanical, and chemical properties included in data. Combined effects of heat and radiation briefly considered. Data summarized in graphic form useful to designers.

  18. Effective Programs for Latino Students.

    ERIC Educational Resources Information Center

    Slavin, Robert E., Ed.; Calderon, Margarita, Ed.

    This collection of papers presents the current state of research on effective instructional programs for Hispanic American students. The 10 chapters are: (1) "Effective Programs for Latino Students in Elementary and Middle Schools" (Olatokunbo S. Fashola, Robert E. Slavin, Margarita Calderon, and Richard Duran); (2) "Effective Dropout Prevention…

  19. HIV Medicines and Side Effects

    MedlinePLUS

    Side Effects of HIV Medicines HIV Medicines and Side Effects (Last updated 1/7/2016; last reviewed 1/7/2016) Key Points HIV medicines help people with ... will depend on a person’s individual needs. Can HIV medicines cause side effects? HIV medicines help people ...

  20. Anomalous Hall effect

    NASA Astrophysics Data System (ADS)

    Nagaosa, Naoto; Sinova, Jairo; Onoda, Shigeki; MacDonald, A. H.; Ong, N. P.

    2010-04-01

    The anomalous Hall effect (AHE) occurs in solids with broken time-reversal symmetry, typically in a ferromagnetic phase, as a consequence of spin-orbit coupling. Experimental and theoretical studies of the AHE are reviewed, focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical works, both playing a crucial role, has been at the heart of these advances. On the theoretical front, the adoption of the Berry-phase concepts has established a link between the AHE and the topological nature of the Hall currents. On the experimental front, new experimental studies of the AHE in transition metals, transition-metal oxides, spinels, pyrochlores, and metallic dilute magnetic semiconductors have established systematic trends. These two developments, in concert with first-principles electronic structure calculations, strongly favor the dominance of an intrinsic Berry-phase-related AHE mechanism in metallic ferromagnets with moderate conductivity. The intrinsic AHE can be expressed in terms of the Berry-phase curvatures and it is therefore an intrinsic quantum-mechanical property of a perfect crystal. An extrinsic mechanism, skew scattering from disorder, tends to dominate the AHE in highly conductive ferromagnets. The full modern semiclassical treatment of the AHE is reviewed which incorporates an anomalous contribution to wave-packet group velocity due to momentum-space Berry curvatures and correctly combines the roles of intrinsic and extrinsic (skew-scattering and side-jump) scattering-related mechanisms. In addition, more rigorous quantum-mechanical treatments based on the Kubo and Keldysh formalisms are reviewed, taking into account multiband effects, and demonstrate the equivalence of all three linear response theories in the metallic regime. Building on results from recent experiment and theory, a tentative global view of the AHE is proposed which summarizes the roles played by intrinsic and extrinsic contributions in the disorder strength versus temperature plane. Finally outstanding issues and avenues for future investigation are discussed.

  1. Effects of Security actions

    NASA Astrophysics Data System (ADS)

    Bergman, Ramona; Andersson-Sköld, Yvonne; Nyberg, Lars; Johansson, Magnus

    2010-05-01

    In a project funded by the Swedish Civil Contingencies Agency, the effort and work to reduce different kinds of accidents are being evaluated. The project wants to illuminate the links between actions and outcome, so we can learn from today's performance and in the future select more effective measures and overall deal with accidents more efficiently. The project ESS covers the field of frequent accidents such as sliding accidents at home, in house fires and less common accidents such as chemical and land fill accidents up to even more rare accidents such as natural accidents and hazards. In the ESS project SGI (Swedish geotechnical institute) will evaluate the work and effort concerning various natural hazards limited to landslides, erosion and flooding. The aim is to investigate how municipalities handle, especially prevention, of such natural disasters today. The project includes several aspects such as: • which are the driving forces for risk analysis in a municipality • do one use risk mapping (and what type) in municipal risk analysis • which aspects are most important when selecting preventive measures • in which way do one learn from past accidents • and from previous accidents elsewhere, by for example use existing databases • etc There are many aspects that play a role in a well-functioning safety promotion work. The overall goal is to examine present work and activities, highlight what is well functioning and identify weak points. The aim is to find out where more resources are needed and give suggestions for a more efficient security work. This includes identification of the most efficient "tools" in use or needed. Such tools can be education, directives, funding, more easily available maps and information regarding previous accidents and preventive measures etc. The project will result in recommendations for more effective ways to deal with landslides, erosion and flooding. Since different kinds of problems can occur depending on level of authority the investigation of the security work will be done with authorities on both regional and local scale. At the moment the investigation process are in progress and preliminary results will be presented.

  2. Effective family planning programs.

    PubMed

    Rosenfield, A G

    1973-01-01

    Organizational and content features of various national family planning programs are reviewed. The Thai program is cited as an example of a family planning program organized on a massive unipurpose compaign basis. The Korean and Taiwan programs have utilized special field workers while upgrading the general health care network. 3 major problems with family planning programs are: 1) the lack of experience with such programs; 2) lack of commitment at the highest political levels; and 3) medical conservatism. Utilization of all available contraceptive methods instead of reliance on 1 method would improve most programs. Nursing and auxiliary personnel could be trained to take over the work of physicians in family planning programs. This is already being done with IUD insertion and pill prescription in several programs. The postpartum tubal ligation approach has proven effective and should be extended. There is a place in all national programs for both the private and the commercial sectors. Incentives for clinics, personnel, and acceptors might spread family planning more rapidly. PMID:12309877

  3. (Limiting the greenhouse effect)

    SciTech Connect

    Rayner, S.

    1991-01-07

    Traveler attended the Dahlem Research Conference organized by the Freien Universitat, Berlin. The subject of the conference was Limiting the Greenhouse Effect: Options for Controlling Atmospheric CO{sub 2} Accumulation. Like all Dahlem workshops, this was a meeting of scientific experts, although the disciplines represented were broader than usual, ranging across anthropology, economics, international relations, forestry, engineering, and atmospheric chemistry. Participation by scientists from developing countries was limited. The conference was divided into four multidisciplinary working groups. Traveler acted as moderator for Group 3 which examined the question What knowledge is required to tackle the principal social and institutional barriers to reducing CO{sub 2} emissions'' The working rapporteur was Jesse Ausubel of Rockefeller University. Other working groups examined the economic costs, benefits, and technical feasibility of options to reduce emissions per unit of energy service; the options for reducing energy use per unit of GNP; and the significant of linkage between strategies to reduce CO{sub 2} emissions and other goals. Draft reports of the working groups are appended. Overall, the conference identified a number of important research needs in all four areas. It may prove particularly important in bringing the social and institutional research needs relevant to climate change closer to the forefront of the scientific and policy communities than hitherto.

  4. The Ratchet Effect

    PubMed Central

    Tenneti, Raji; Marsh, Julie; Bolt, Sarah E.; Kemp, Anna; Firth, Laura; Murray, Kevin; Turlach, Berwin; Vickery, Alistair

    2014-01-01

    Objective: To describe the previously unexamined association between admissions to hospital with chronic disease and changes in all-cause health service utilization over time. Research Design: A cohort study examining the population of Western Australia with hospitalizations for chronic disease from 2002 to 2010. A “rolling” clearance period is used to define “cardinal events,” that is, a disease-specific diagnosis upon hospital admission, where such an event has not occurred in the previous 2 years. Changes in the rate of cardinal events associated with diagnoses of heart failure, type 2 diabetes, chronic obstructive pulmonary disease, cataract with diabetes, asthma, and dialysis are examined. Health service utilization (defined as inpatient days or emergency department presentations) 6 years preceding and 4 years following such events is presented. Results: Cardinal events make up 40%–60% of all chronic disease admissions. A previously undescribed ratchet effect following cardinal events specifically associated with type 2 diabetes, heart failure, and chronic obstructive pulmonary disease is observed. This involves a 2- to 3-fold increase in inpatient days and emergency department presentations that are sustained for at least 4 years. Conclusions: Cardinal events represent an important reference point to understand the impact of chronic disease on health service utilization. Events that herald such a marked transition in health service demand have not been previously described. PMID:25054825

  5. The photorefractive effect

    SciTech Connect

    Pepper, D.M. ); Kukhtarev, N.V. )

    1990-10-01

    When Arthur Ashkin and his colleagues at Bell Laboratories first noticed the photorefractive effect some 25 years ago, they considered the phenomenon a curiosity at best and a complete nuisance at worst. Today photorefractive materials are being shaped into components for a new generation of computers that exploit light instead of electricity. During the past 25 years investigators have discovered a wide variety of photorefractive materials, including insulators, semiconductors and organic compounds. Photorefractive materials, like film emulsions, change rapidly when exposed to bright light, respond slowly when subjected to dim light and capture sharp detail when struck by some intricate pattern of light. Unlike film, photorefractive materials are erasable: images can be stored or obliterated at whim or by design. By virtue of their sensitivity, robustness, and unique optical properties, photorefractive materials have the potential to be fashioned into data-processing elements for optical computers. In theory, these devices would allow optical computers to process information at much faster rates than their electronic counterparts. Employing photorefractive materials, workers have already developed the optical analogue to the transistor: if two laser beams interact within a photorefractive material, one beam can control, switch or amplify the second beam. Photorefractive materials also lie at the heart of devices that trace the edges of images, that connect networks of lasers and that store three-dimensional images.

  6. Effective Physics Study Habits

    NASA Astrophysics Data System (ADS)

    Zettili, Nouredine

    2011-04-01

    We discuss the methods of efficient study habits and how they can be used by students to help them improve learning physics. In particular, we deal with ideas pertaining to the most effective techniques needed to help students improve their physics study skills. These ideas were developed as part of Project IMPACTSEED (IMproving Physics And Chemistry Teaching in SEcondary Education), an outreach grant funded by the Alabama Commission on Higher Education. This project is motivated by a major pressing local need: A large number of high school physics teachers teach out of field. In the presentation, focus on topics such as the skills of how to develop long term memory, how to improve concentration power, how to take class notes, how to prepare for and take exams, how to study scientific subjects such as physics. We argue that the student who conscientiously uses the methods of efficient study habits will be able to achieve higher results than the student who does not; moreover, a student equipped with the proper study skills will spend much less time to learn a subject than a student who has no good study habits. The underlying issue here is not the quantity of time allocated to the study efforts by the student, but the efficiency and quality of actions. This work is supported by the Alabama Commission on Higher Education as part of IMPACTSEED grant.

  7. Harmful effects of nicotine.

    PubMed

    Mishra, Aseem; Chaturvedi, Pankaj; Datta, Sourav; Sinukumar, Snita; Joshi, Poonam; Garg, Apurva

    2015-01-01

    With the advent of nicotine replacement therapy, the consumption of the nicotine is on the rise. Nicotine is considered to be a safer alternative of tobacco. The IARC monograph has not included nicotine as a carcinogen. However there are various studies which show otherwise. We undertook this review to specifically evaluate the effects of nicotine on the various organ systems. A computer aided search of the Medline and PubMed database was done using a combination of the keywords. All the animal and human studies investigating only the role of nicotine were included. Nicotine poses several health hazards. There is an increased risk of cardiovascular, respiratory, gastrointestinal disorders. There is decreased immune response and it also poses ill impacts on the reproductive health. It affects the cell proliferation, oxidative stress, apoptosis, DNA mutation by various mechanisms which leads to cancer. It also affects the tumor proliferation and metastasis and causes resistance to chemo and radio therapeutic agents. The use of nicotine needs regulation. The sale of nicotine should be under supervision of trained medical personnel. PMID:25810571

  8. Effectively Rebutting Climate Misinformation

    NASA Astrophysics Data System (ADS)

    Cook, J.

    2011-12-01

    Climate science faces one of the best funded misinformation campaigns in history. The challenge for climate communicators is that misinformation is extremely difficult to dislodge, even after people understand that it's incorrect. Understanding how the human brain processes information is crucial to successful rebuttal. To avoid the danger of reinforcing misinformation (known as the 'backfire effect'), emphasis should be on positive facts, not the myth. Another key to dislodging myths is replacing them with an alternate narrative. In order to provide a narrative about arguments that misrepresent climate science, a broader understanding of how these arguments mislead is required. Movements that deny a scientific consensus have 5 characteristics in common and these also apply to climate denial. The arguments against the scientific consensus involve conspiracy theories, fake experts, cherry picking, logical fallacies and misrepresentation or impossible expectations. Learning to identify these rhetorical techniques is an important tool in the climate communication toolbox. I discuss examples of misrepresentations of climate science and the rhetorical techniques employed. I demonstrate how to respond to these arguments by explaining the facts of climate science while in the process, providing an alternate narrative.

  9. The Second Mössbauer Effect

    NASA Astrophysics Data System (ADS)

    Kienle, Paul

    "The Second Mössbauer Effect" was the headline of the "Spiegel" (a German weekly journal like the "Times") from May 13, 1964 for announcing the foundation of the "Physik-Department" at the Technische Hochschule München (THM), as it was still called at this time. Maier-Leibnitz was irritated by this headline because the article did not mention at all his contribution to the consolidation of the structure of the three physics institutes (Experimental, Technical, and Theoretical Physics) in the beginning of the sixties. Already in the late fifties ML's Institute for Technical Physics was overloaded with students working on their diploma or doctoral theses, because research in the new field of applied nuclear physics was very attractive and ML had for each student who applied an interesting research project. In the average, ML had to supervise between 150-200 diploma students, an impossible task. So, young postdoctoral students had to help him out by taking over the duties of professors. In a letter to the Bavarian Ministry of Education and Arts in 1957 he complained: "The directors of the institutes are hopelessly surcharged and the institutes are overcrowded, the resources for research projects are totally insufficient and lots of time and energy is wasted for finding additional resources."

  10. Neuroprotective effects of ginsenosides.

    PubMed

    Rausch, Wolf-Dieter; Liu, Shu; Gille, Gabriele; Radad, Khaled

    2006-01-01

    Ginseng, the root of the Panax species, is a well-known herbal medicine. Traditionally it has been used in Korea, China and Japan for thousands of years. Nowadays it has become a popular and worldwide known health drug. Current scientific studies demonstrate in vivo and in vitro its beneficial effects in a wide range of pathological conditions such as cardiovascular disease, cancer, immune deficiency and hepatotoxicity. Ginsenosides or ginseng saponins as the active ingredients have antioxidant, anti-inflammatory, anti-apoptotic and immunostimulant properties, which raised speculations that these compounds could positively affect neurodegenerative disorders and delay neuronal aging. Conclusive clinical data in humans are still missing. However, results from animal studies and neuronal cell culture experiments indicate that ginsenosides can counteract and attenuate factors promoting neuronal death as environmental toxins, excitotoxic action of glutamate and rises in intracellular calcium, excessive release of free radicals and apoptotic events. Thus, neuroprotective actions of ginsenosides could come about as a valuable option to slow down neurodegenerative diseases. PMID:17265697

  11. Melatonin anticancer effects: review.

    PubMed

    Di Bella, Giuseppe; Mascia, Fabrizio; Gualano, Luciano; Di Bella, Luigi

    2013-01-01

    Melatonin (N-acetyl-5-methoxytryptamine, MLT), the main hormone produced by the pineal gland, not only regulates circadian rhythm, but also has antioxidant, anti-ageing and immunomodulatory properties. MLT plays an important role in blood composition, medullary dynamics, platelet genesis, vessel endothelia, and in platelet aggregation, leukocyte formula regulation and hemoglobin synthesis. Its significant atoxic, apoptotic, oncostatic, angiogenetic, differentiating and antiproliferative properties against all solid and liquid tumors have also been documented. Thanks, in fact, to its considerable functional versatility, MLT can exert both direct and indirect anticancer effects in factorial synergy with other differentiating, antiproliferative, immunomodulating and trophic molecules that form part of the anticancer treatment formulated by Luigi Di Bella (Di Bella Method, DBM: somatostatin, retinoids, ascorbic acid, vitamin D3, prolactin inhibitors, chondroitin-sulfate). The interaction between MLT and the DBM molecules counters the multiple processes that characterize the neoplastic phenotype (induction, promotion, progression and/or dissemination, tumoral mutation). All these particular characteristics suggest the use of MLT in oncological diseases. PMID:23348932

  12. Perceptual Repetition Blindness Effects

    NASA Technical Reports Server (NTRS)

    Hochhaus, Larry; Johnston, James C.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    The phenomenon of repetition blindness (RB) may reveal a new limitation on human perceptual processing. Recently, however, researchers have attributed RB to post-perceptual processes such as memory retrieval and/or reporting biases. The standard rapid serial visual presentation (RSVP) paradigm used in most RB studies is, indeed, open to such objections. Here we investigate RB using a "single-frame" paradigm introduced by Johnston and Hale (1984) in which memory demands are minimal. Subjects made only a single judgement about whether one masked target word was the same or different than a post-target probe. Confidence ratings permitted use of signal detection methods to assess sensitivity and bias effects. In the critical condition for RB a precue of the post-target word was provided prior to the target stimulus (identity precue), so that the required judgement amounted to whether the target did or did not repeat the precue word. In control treatments, the precue was either an unrelated word or a dummy (XXXX). Results of five experiments show that perceptual sensitivity is strikingly and significantly reduced in the RB condition relative to both baseline control conditions. The data show RB can be obtained under conditions in which memory problems are minimal and where perceptual sensitivity is assessed independently of biases.

  13. Health effects from fallout.

    PubMed

    Gilbert, Ethel S; Land, Charles E; Simon, Steven L

    2002-05-01

    This paper primarily discusses health effects that have resulted from exposures received as a result of above-ground nuclear tests, with emphasis on thyroid disease from exposure to 131I and leukemia and solid cancers from low dose rate external and internal exposure. Results of epidemiological studies of fallout exposures in the Marshall Islands and from the Nevada Test Site are summarized, and studies of persons with exposures similar to those from fallout are briefly reviewed (including patients exposed to 131I for medical reasons and workers exposed externally at low doses and low dose rates). Promising new studies of populations exposed in countries of the former Soviet Union are also discussed and include persons living near the Semipalatinsk Test Site in Kazakhstan, persons exposed as a result of the Chernobyl accident, and persons exposed as a result of operations of the Mayak Nuclear Plant in the Russian Federation. Very preliminary estimates of cancer risks from fallout doses received by the United States population are presented. PMID:12003021

  14. The alpha channeling effect

    NASA Astrophysics Data System (ADS)

    Fisch, N. J.

    2015-12-01

    Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

  15. Melatonin Anticancer Effects: Review

    PubMed Central

    Di Bella, Giuseppe; Mascia, Fabrizio; Gualano, Luciano; Di Bella, Luigi

    2013-01-01

    Melatonin (N-acetyl-5-methoxytryptamine, MLT), the main hormone produced by the pineal gland, not only regulates circadian rhythm, but also has antioxidant, anti-ageing and immunomodulatory properties. MLT plays an important role in blood composition, medullary dynamics, platelet genesis, vessel endothelia, and in platelet aggregation, leukocyte formula regulation and hemoglobin synthesis. Its significant atoxic, apoptotic, oncostatic, angiogenetic, differentiating and antiproliferative properties against all solid and liquid tumors have also been documented. Thanks, in fact, to its considerable functional versatility, MLT can exert both direct and indirect anticancer effects in factorial synergy with other differentiating, antiproliferative, immunomodulating and trophic molecules that form part of the anticancer treatment formulated by Luigi Di Bella (Di Bella Method, DBM: somatostatin, retinoids, ascorbic acid, vitamin D3, prolactin inhibitors, chondroitin-sulfate). The interaction between MLT and the DBM molecules counters the multiple processes that characterize the neoplastic phenotype (induction, promotion, progression and/or dissemination, tumoral mutation). All these particular characteristics suggest the use of MLT in oncological diseases. PMID:23348932

  16. Harmful effects of nicotine

    PubMed Central

    Mishra, Aseem; Chaturvedi, Pankaj; Datta, Sourav; Sinukumar, Snita; Joshi, Poonam; Garg, Apurva

    2015-01-01

    With the advent of nicotine replacement therapy, the consumption of the nicotine is on the rise. Nicotine is considered to be a safer alternative of tobacco. The IARC monograph has not included nicotine as a carcinogen. However there are various studies which show otherwise. We undertook this review to specifically evaluate the effects of nicotine on the various organ systems. A computer aided search of the Medline and PubMed database was done using a combination of the keywords. All the animal and human studies investigating only the role of nicotine were included. Nicotine poses several health hazards. There is an increased risk of cardiovascular, respiratory, gastrointestinal disorders. There is decreased immune response and it also poses ill impacts on the reproductive health. It affects the cell proliferation, oxidative stress, apoptosis, DNA mutation by various mechanisms which leads to cancer. It also affects the tumor proliferation and metastasis and causes resistance to chemo and radio therapeutic agents. The use of nicotine needs regulation. The sale of nicotine should be under supervision of trained medical personnel. PMID:25810571

  17. Public Opinion on Mass Media Effects: Perceived Societal Effects and Perceived Personal Effects.

    ERIC Educational Resources Information Center

    Tiedge, James T.

    The questionnaire in a study of perceived mass media effects included nine statements about the possible negative effects of the mass media, to which respondents could agree, disagree, or indicate "no opinion," and an open-ended question that asked the subjects what effects the mass media had on them personally. Most of the 340 respondents showed…

  18. Natural convection heat exchangers for solar water heating systems. Technical progress report, May 15, 1996--July 14, 1996

    SciTech Connect

    Davidson, J.H.

    1998-06-01

    This progress report very briefly summarizes study results and includes an experimental plan developed for the fundamental study of heat transfer in thermosyphon side-arm heat exchangers. The study will investigate the influence of the Reynolds and Grashof numbers on the thermosyphon flow side of the heat exchanger, and the influence of the flow rate on the forced flow side of the heat exchanger. Detailed temperature, flow rate, and pressure data will be obtained for four, seven, and nine tube-in-shell heat exchanger designs. Correlations will be developed for the heat transfer and friction coefficients, and a semi-empirical model will be developed to predict the performance of thermosyphon heat exchangers in solar water heaters.

  19. Testing the Perey effect

    NASA Astrophysics Data System (ADS)

    Titus, L. J.; Nunes, F. M.

    2014-03-01

    Background: The effects of nonlocal potentials have historically been approximately included by applying a correction factor to the solution of the corresponding equation for the local equivalent interaction. This is usually referred to as the Perey correction factor. Purpose: In this work we investigate the validity of the Perey correction factor for single-channel bound and scattering states, as well as in transfer (p,d) cross sections. Method: We solve the scattering and bound state equations for nonlocal interactions of the Perey-Buck type, through an iterative method. Using the distorted wave Born approximation, we construct the T matrix for (p,d) on 17O, 41Ca, 49Ca, 127Sn, 133Sn, and 209Pb at 20 and 50 MeV. Results: We found that for bound states, the Perey corrected wave function resulting from the local equation agreed well with that from the nonlocal equation in the interior region, but discrepancies were found in the surface and peripheral regions. Overall, the Perey correction factor was adequate for scattering states, with the exception of a few partial waves corresponding to the grazing impact parameters. These differences proved to be important for transfer reactions. Conclusions: If only local optical potentials are used in the analysis of experimental (p,d) cross sections, without any correction factors, as compared to the analysis with nonlocal potentials, the spectroscopic factors could be affected by approximately 20%. The Perey correction factor does offer an improvement over taking a direct local equivalent solution. However, if the desired accuracy is to be better than 10%, the exact solution of the nonlocal equation should be pursued.

  20. Neuroendocrine effects of light

    NASA Astrophysics Data System (ADS)

    Reiter, Russel J.

    1991-09-01

    The light/dark cycle to which animals, and possibly humans, are exposed has a major impact on their physiology. The mechanisms whereby specific tissues respond to the light/dark cycle involve the pineal hormone melatonin. The pineal gland, an end organ of the visual system in mammals, produces the hormone melatonin only at night, at which time it is released into the blood. The duration of elevated nightly melatonin provides every tissue with information about the time of day and time of year (in animals that are kept under naturally changing photoperiods). Besides its release in a circadian mode, melatonin is also discharged in a pulsatile manner; the physiological significance, if any, of pulsatile melatonin release remains unknown. The exposure of animals including man to light at night rapidly depresses pineal melatonin synthesis and, therefore, blood melatonin levels drop precipitously. The brightness of light at night required to depress melatonin production is highly species specific. In general, the pineal gland of nocturnally active mammals, which possess rod-dominated retinas, is more sensitive to inhibition by light than is the pineal gland of diurnally active animals (with cone-dominated retinas). Because of the ability of the light/dark cycle to determine melatonin production, the photoperiod is capable of influencing the function of a variety of endocrine and non-endocrine organs. Indeed, melatonin is a ubiquitously acting pineal hormone with its effects on the neuroendocrine system having been most thoroughly investigated. Thus, in nonhuman photoperiodic mammals melatonin regulates seasonal reproduction; in humans also, the indole has been implicated in the control of reproductive physiology.

  1. Effective potential in the boundary effective theory formalism

    NASA Astrophysics Data System (ADS)

    Bessa, A.; de Carvalho, C. A. A.; Fraga, E. S.; Gelis, F.

    2011-06-01

    We calculate the one-loop effective potential at finite temperature for a system of massless scalar fields with quartic interaction ??4 in the framework of the boundary effective theory formalism. The calculation relies on the solution of the classical equation of motion for the field and Gaussian fluctuations around it. Our result is nonperturbative and differs from the standard one-loop effective potential for field values larger than T/?.

  2. Effect of handling on positive and negative contrast effects.

    PubMed

    Fagen, J W; Rycek, R F

    1980-01-01

    The effects of early handling on the exhibition of positive and negative contrast effects were investigated. Over two 4-day testing sessions, animals were given alternating 1-min access periods to 2 bottles containing either 32 or 4% sucrose solutions. Measures of lick rate and latency to switch bottles revealed that both handled and nonhandled animals exhibited contrast effects of equal magnitudes. The results did not support an emotional interpretation of contrast effects but were interpreted as support for the perceptual theory of this phenomenon. PMID:7353721

  3. Functional mixed effects spectral analysis

    PubMed Central

    KRAFTY, ROBERT T.; HALL, MARTICA; GUO, WENSHENG

    2011-01-01

    SUMMARY In many experiments, time series data can be collected from multiple units and multiple time series segments can be collected from the same unit. This article introduces a mixed effects Cramér spectral representation which can be used to model the effects of design covariates on the second-order power spectrum while accounting for potential correlations among the time series segments collected from the same unit. The transfer function is composed of a deterministic component to account for the population-average effects and a random component to account for the unit-specific deviations. The resulting log-spectrum has a functional mixed effects representation where both the fixed effects and random effects are functions in the frequency domain. It is shown that, when the replicate-specific spectra are smooth, the log-periodograms converge to a functional mixed effects model. A data-driven iterative estimation procedure is offered for the periodic smoothing spline estimation of the fixed effects, penalized estimation of the functional covariance of the random effects, and unit-specific random effects prediction via the best linear unbiased predictor.

  4. Geologic effects of hurricanes

    NASA Astrophysics Data System (ADS)

    Coch, Nicholas K.

    1994-08-01

    Hurricanes are intense low pressure systems of tropical origin. Hurricane damage results from storm surge, wind, and inland flooding from heavy rainfall. Field observations and remote sensing of recent major hurricanes such as Hugo (1989), Andrew (1992) and Iniki (1992) are providing new insights into the mechanisms producing damage in these major storms. Velocities associated with hurricanes include the counterclockwise vortex winds flowing around the eye and the much slower regional winds that steer hurricane and move it forward. Vectorial addition of theseof these two winds on the higher effective wind speed than on the left side. Coast-parallel hurricane tracks keep the weaker left side of the storm against the coast, whereas coast-normal tracks produce a wide swath of destruction as the more powerful right side of the storm cuts a swath of destruction hundreds of kilometers inland. Storm surge is a function of the wind speed, central pressure, shelf slope, shoreline configuration, and anthropogenic alterations to the shoreline. Maximum surge heights are not under the eye of the hurricane, where the pressure is lowest, but on the right side of the eye at the radius of maximum winds, where the winds are strongest. Flood surge occurs as the hurricane approaches land and drives coastal waters, and superimposed waves, across the shore. Ebb surge occurs when impounded surface water flows seaward as the storm moves inland. Flood and ebb surge damage have been greatly increased in recent hurricanes as a result of anthropogenic changes along the shoreline. Hurricane wind damage occurs on three scales — megascale, mesoscale and microscale. Local wind damage is a function of wind speed, exposure and structural resistance to velocity pressure, wind drag and flying debris. Localized extreme damage is caused by gusts that can locally exceed sustained winds by a factor of two in areas where there is strong convective activity. Geologic changes occuring in hurricanes include beach erosion, dune erosion, inlet formation from flood and ebb surge, landscape changes through tree destruction by wind and nearshore channeling and sedimentation resulting from ebb surge. Multi-decadal wet and dry cycles in West Africa seem to be associated with increases (wet periods) and decreases (dry periods) in the frequency of Atlantic Coast landfalling hurricanes. Coastalzone population and development has increased markedly in a time of low hurricane frequency in the 24 year dry cycle from1970 to the present. However, no previous climatic cycle in this century has exceeded 26 years. We may entering a multi-decadal cycle of greater hurricane activity, placing these highly urbanized shorelines in considerable danger.

  5. Magnetocaloric effect in manganites

    SciTech Connect

    Koroleva, L. I. Zashchirinskii, D. M.; Morozov, A. S.; Szymczak, R.

    2012-10-15

    The magnetocaloric effect (MCE) in La{sub 1-x}Sr{sub x}MnO{sub 3}, Sm{sub 0.55}Sr{sub 0.45}MnO{sub 3}, and PrBaMn{sub 2}O{sub 6} compounds is studied. The maximum values of MCE ({Delta}T{sub max}) determined by a direct method in the second and third compositions and in La{sub 0.9}Sr{sub 0.1}MnO{sub 3} are found to be much lower than those calculated from the change of the magnetic part of entropy in the Curie temperature (T{sub C}) and the Neel temperature (T{sub N}) range. The negative contribution of the antiferromagnetic (AFM) part of a sample in the La{sub 1-x}Sr{sub x}MnO{sub 3} system at 0.1 {<=} x {<=} 0.3 decreases {Delta}T{sub max} and changes the {Delta}T(T) curve shape, shifting its maximum 20-40 K above T{sub C}. Lower values of {Delta}T{sub max} are detected in the range T{sub C} = 130-142 K in polycrystalline and single-crystal Sm{sub 0.55}Sr{sub 0.45}MnO{sub 3} samples cooled in air. If such samples were cooled in an oxygen atmosphere (which restores broken Mn-O-Mn bonds and, thus, increases the volume of CE-type AFM clusters), the maximum in the temperature dependence of MCE is located at T{sub N} (243 K) for CE-type AFM clusters. A magnetic field applied to a sample during the MCE measurements transforms these clusters into a ferromagnetic (FM) state, and both types of clusters decompose at T = T{sub N}. The PrBaMn{sub 2}O{sub 6} composition undergoes an AFM-FM transition at 231 K, and the temperature dependence of its MCE has a sharp minimum at T = 234 K, where MCE is negative, and a broad maximum covering T{sub C}. The absolute values of MCE at both extrema are several times lower than those calculated from the change in the magnetic entropy. These phenomena are explained by the presence of a magnetically heterogeneous FM-AFM state in these manganites.

  6. Radiation Effects: Core Project

    NASA Technical Reports Server (NTRS)

    Dicello, John F.

    1999-01-01

    The risks to personnel in space from the naturally occurring radiations are generally considered to be one of the most serious limitations to human space missions, as noted in two recent reports of the National Research Council/National Academy of Sciences. The Core Project of the Radiation Effects Team for the National Space Biomedical Research Institute is the consequences of radiations in space in order to develop countermeasure, both physical and pharmaceutical, to reduce the risks of cancer and other diseases associated with such exposures. During interplanetary missions, personnel in space will be exposed to galactic cosmic rays, including high-energy protons and energetic ions with atomic masses of iron or higher. In addition, solar events will produce radiation fields of high intensity for short but irregular durations. The level of intensity of these radiations is considerably higher than that on Earth's surface, and the biological risks to astronauts is consequently increased, including increased risks of carcinogenesis and other diseases. This group is examining the risk of cancers resulting from low-dose, low-dose rate exposures of model systems to photons, protons, and iron by using ground-based accelerators which are capable of producing beams of protons, iron, and other heavy ions at energies comparable to those encountered in space. They have begun the first series of experiments using a 1-GeV iron beam at the Brookhaven National Laboratory and 250-MeV protons at Loma Linda University Medical Center's proton synchrotron facility. As part of these studies, this group will be investigating the potential for the pharmaceutical, Tamoxifen, to reduce the risk of breast cancer in astronauts exposed to the level of doses and particle types expected in space. Theoretical studies are being carried out in a collaboration between scientists at NASA's Johnson Space Center and Johns Hopkins University in parallel with the experimental program have provided methods and predictions which are being used to assess the levels of risks to be encountered and to evaluate appropriate strategies for countermeasures. Although the work in this project is primarily directed toward problems associated with space travel, the problem of protracted exposures to low-levels of radiation is one of national interest in our energy and defense programs, and the results may suggest new paradigms for addressing such risks.

  7. The wow effect

    NASA Astrophysics Data System (ADS)

    Biondi, Riccardo; Pagnotta, Paola; Trentini, Gabriella; Cirotti, Tiziana; Parrettini, Cinzia

    2015-04-01

    Teaching science at elementary school is a hard work for scientists since we usually use to talk to colleagues by using technical and specific words not understandable by general public and school students. Finding plain language for explaining what is the research and for describing scientific topics was the objective of this work. In collaboration with the school teachers, I organized a series of meetings describing the same subject with different approaches and, at the end of the test-period, we did a survey within the 60 students (10-11 years old) for understanding which was the most attractive approach for them. The survey asked to the students the 3 topics (which could be a sentence, an activity or simply a picture) that they remember at most from all the meetings. Later on we asked why they have chosen those topics. The common topic was atmospheric and space science and it was approached by using, books, videos, frontal lectures with the support of pictures and other material, and with direct hands-on lab such as 3D puzzles for building a satellite. Nobody highlights having read a book. The majority of the students (male and female) really appreciated having built their own satellite (wow, I have done it!) and how's the life into the International Space Station (wow, everything flies there and they drink the pee!). Many female students were fascinated by the stars and by the Italian astronaut Samantha Cristoforetti (wow, an Italian woman is there!) while many boys were attracted by the technology evolution (wow, how a mobile phone could be that big?!). Surprisingly 3 students remember a quick (showed for just a few seconds) and blurred picture showing the glory effect by aircraft (wow, a circular rainbow!). The survey shows how the students mostly appreciate the hands-on labs and being active and creative, their attention decreases but it is still active with frontal lectures or videos showing them real examples or something impacting their day-life.

  8. Reverse coffee-ring effect

    NASA Astrophysics Data System (ADS)

    Mook Weon, Byung; Xu, Lei; Je, Jung Ho; Hwu, Yeukuang; Margaritondo, Giorgio; Weitz, David A.

    2009-03-01

    When a coffee drop dries on a solid surface, it commonly leaves a ring-like deposit along the edge, known as the coffee-ring effect. We present a reverse motion of particles in drying droplets, opposite to the coffee-ring effect. We reveal that the particle motion, initially toward the edge by the typical coffee-ring effect, is reversed to the droplet center owing to the capillary interaction generated by the droplet surface. The reverse coffee-ring effect always occurs whenever the capillary interaction prevails over the net outward force by the coffee- ring effect. The interaction predicts an inverse power-law time growth of moving distance from the edge, depending mostly on particle size and contact angle. The reverse coffee-ring effect may contribute to multiple ring formation by sweeping particles toward the center. We prove the mechanism with real-time optical, confocal, and X-ray microscopic observations of colloidal fluids.

  9. Antigonococcal effects of vaginal tampons.

    PubMed

    Arko, R J; Wong, K H; Smith, S J; Finley-Price, K G

    1983-04-01

    Different brands of vaginal tampons varied significantly (p less than 0.0001) in their anti-bacterial effects when tested with 46 strains of Neisseria gonorrhoeae. Gonococcal strains recovered from patients with disseminated infections were substantially more sensitive to the anti-bacterial effects of tampons than were strains from patients with uncomplicated genital infections. Strains from patients with pelvic inflammatory disease were moderately sensitive. Tampons showing strong in-vitro antigonococcal effects were also generally effective in vivo in eliminating gonococcal infections from subcutaneous chambers in mice. Extracts of the Rely tampon showed no in-vitro antigonococcal effect, however, but did induce antibacterial activity when injected into subcutaneous chambers in mice. These results emphasise the importance of both in-vitro as well as in-vivo testing of tampon materials to elucidate more fully the nature of their antibacterial effects and their potential for affecting vaginal pathogens and disease processes. PMID:6403199

  10. Microstructural effects in shock ignition

    SciTech Connect

    Conley, P.; Benson, D.; Howe, P.M.

    1998-07-01

    The dynamic response of explosive microstructures has been explicitly modeled, with the intention of gaining insight into initiation processes from hotspot formation to transition to detonation. In this paper, the authors focus attention upon the inert material response leading to hotspot ignition. Of interest are particle size and shape effects, constitutive effects of both binder and explosive, and their importance to hotspot formation. Effects of chemical reaction are considered elsewhere.

  11. The Thirring-Lense Effect

    NASA Astrophysics Data System (ADS)

    Embacher, Franz

    The Thirring-Lense effect is the phenomenon that an observer near a rotating mass, being in a state which is non-rotating with respect to the rest of the universe, experiences extra inertial forces, i.e. becomes dizzy. The first anticipation of the effect goes back to Ernst Mach; its first quantitative prediction on the basis of general relativity was given by Hans Thirring and Joseph Lense. Almost ninety years later, the effect seems to be experimentally verified.

  12. Biological Effects of Ionizing Radiation

    DOE R&D Accomplishments Database

    Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

    1952-04-07

    This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

  13. Semiotics and the placebo effect.

    PubMed

    Miller, Franklin G; Colloca, Luana

    2010-01-01

    Despite substantial progress in elucidating its neurobiological mechanisms, theoretical understanding of the placebo effect is poorly developed. Application of the semiotic theory developed by the American philosopher Charles Peirce offers a promising account of placebo effects as involving the apprehension and response to signs. The semiotic approach dovetails with the various psychological mechanisms invoked to account for placebo effects, such as conditioning and expectation, and bridges the biological and cultural dimensions of this fascinating phenomenon. PMID:21037405

  14. Modelling of the YORP effect

    NASA Astrophysics Data System (ADS)

    Golubov, O.

    2015-10-01

    In the talk I will review the recent advances in the theoretical understanding of the YORP effect. I describe the standard mathematical formalism used for the YORP effect, with the special focus on the limitations of the standard theory and its possible genaralizations. I discuss the sensitivity of the YORP effect to small-scale structures and the novel concept of the tangential YORP, a torque that alters even the rotation of symmetric asteroids due to uneven heat conductivity in small stones composing the surface. Finally, I consider the overall evolution of an asteroid experiencing the YORP effect.

  15. TOLUENE DOSE-EFFECT META ANALYSIS AND IMPORTANCE OF EFFECTS

    EPA Science Inventory

    TOLUENE DOSE-EFFECT META ANALYSES AND IMPORTANCE OF EFFECTS
    Benignus, V.A., Research Psychologist, ORD, NHEERL, Human Studies Division,
    919-966-6242, benignus.vernon@epa.gov
    Boyes, W.K., Supervisory Health Scientist, ORD, NHEERL, Neurotoxicology Division
    919-541-...

  16. Effects beyond Effectiveness: Teaching as a Performative Act

    ERIC Educational Resources Information Center

    Liew, Warren Mark

    2013-01-01

    This article develops the familiar metaphor of teaching as performance towards a definition of "teaching as performative act," where words and actions aim to effect cognitive, affective, and behavioral changes in learners. To what extent, however, are the consequences of pedagogical actions commensurate with their intended effects? Can a science…

  17. EFFECTIVE POROSITY IMPLIES EFFECTIVE BULK DENSITY IN SORBING SOLUTE TRANSPORT

    SciTech Connect

    Flach, G.

    2012-02-27

    The concept of an effective porosity is widely used in solute transport modeling to account for the presence of a fraction of the medium that effectively does not influence solute migration, apart from taking up space. This non-participating volume or ineffective porosity plays the same role as the gas phase in single-phase liquid unsaturated transport: it increases pore velocity, which is useful towards reproducing observed solute travel times. The prevalent use of the effective porosity concept is reflected by its prominent inclusion in popular texts, e.g., de Marsily (1986), Fetter (1988, 1993) and Zheng and Bennett (2002). The purpose of this commentary is to point out that proper application of the concept for sorbing solutes requires more than simply reducing porosity while leaving other material properties unchanged. More specifically, effective porosity implies the corresponding need for an effective bulk density in a conventional single-porosity model. The reason is that the designated non-participating volume is composed of both solid and fluid phases, both of which must be neglected for consistency. Said another way, if solute does not enter the ineffective porosity then it also cannot contact the adjoining solid. Conceptually neglecting the fluid portion of the non-participating volume leads to a lower (effective) porosity. Likewise, discarding the solid portion of the non-participating volume inherently leads to a lower or effective bulk density. In the author's experience, practitioners virtually never adjust bulk density when adopting the effective porosity approach.

  18. Costs of antibiotic resistance – separating trait effects and selective effects

    PubMed Central

    Hall, Alex R; Angst, Daniel C; Schiessl, Konstanze T; Ackermann, Martin

    2015-01-01

    Antibiotic resistance can impair bacterial growth or competitive ability in the absence of antibiotics, frequently referred to as a ‘cost’ of resistance. Theory and experiments emphasize the importance of such effects for the distribution of resistance in pathogenic populations. However, recent work shows that costs of resistance are highly variable depending on environmental factors such as nutrient supply and population structure, as well as genetic factors including the mechanism of resistance and genetic background. Here, we suggest that such variation can be better understood by distinguishing between the effects of resistance mechanisms on individual traits such as growth rate or yield (‘trait effects’) and effects on genotype frequencies over time (‘selective effects’). We first give a brief overview of the biological basis of costs of resistance and how trait effects may translate to selective effects in different environmental conditions. We then review empirical evidence of genetic and environmental variation of both types of effects and how such variation may be understood by combining molecular microbiological information with concepts from evolution and ecology. Ultimately, disentangling different types of costs may permit the identification of interventions that maximize the cost of resistance and therefore accelerate its decline. PMID:25861384

  19. Effective Leadership for Effective Schools: A Survey of Principal Attitudes.

    ERIC Educational Resources Information Center

    Arnn, John W., Jr.; Mangieri, John N.

    1988-01-01

    Effective principals agree on what should be occurring in the classrooms in their schools, according to investigators who queried principals in 202 schools identified as "effective." The most important characteristic of teachers, they responded, is to be task-oriented. (CJH)

  20. The Worked Example Effect, the Generation Effect, and Element Interactivity

    ERIC Educational Resources Information Center

    Chen, Ouhao; Kalyuga, Slava; Sweller, John

    2015-01-01

    The worked example effect indicates that examples providing full guidance on how to solve a problem result in better test performance than a problem-solving condition with no guidance. The generation effect occurs when learners generating responses demonstrate better test performance than learners in a presentation condition that provides an…

  1. Effects of Small Oscillations on the Effective Area

    SciTech Connect

    Cotroneo, V.; Conconi, P.; Pareschi, G.; Spiga, D.; Tagliaferri, G.

    2009-05-11

    We analyze the effective area of the Simbol-X mirrors as a function of the off-axis angle for small oscillations. A reduction is expected due to: 1) geometrical effects, because some of the photons miss the secondary mirror surface; 2) reflectivity effects, caused by the variation of the coating reflectivity with the incidence angle. The former are related to the length of the two mirror surfaces, and can be reduced by making the secondary mirror longer. The second ones are energy-dependent, and strongly related to the characteristics of the reflecting coating. These effects are analyzed by means of ray-tracing simulations in order to optimize the mirror and coating design, aiming to improve the effective area stability.

  2. A side effect resource to capture phenotypic effects of drugs

    PubMed Central

    Kuhn, Michael; Campillos, Monica; Letunic, Ivica; Jensen, Lars Juhl; Bork, Peer

    2010-01-01

    The molecular understanding of phenotypes caused by drugs in humans is essential for elucidating mechanisms of action and for developing personalized medicines. Side effects of drugs (also known as adverse drug reactions) are an important source of human phenotypic information, but so far research on this topic has been hampered by insufficient accessibility of data. Consequently, we have developed a public, computer-readable side effect resource (SIDER) that connects 888 drugs to 1450 side effect terms. It contains information on frequency in patients for one-third of the drug–side effect pairs. For 199 drugs, the side effect frequency of placebo administration could also be extracted. We illustrate the potential of SIDER with a number of analyses. The resource is freely available for academic research at http://sideeffects.embl.de. PMID:20087340

  3. Effect of orientation anisotropy on calculating effective electrical conductivities

    NASA Astrophysics Data System (ADS)

    Myles, Timothy D.; Peracchio, Aldo A.; Chiu, Wilson K. S.

    2014-05-01

    This paper develops an analytical effective medium theory (EMT) equation for calculating the effective conductivity of a mixture based on Maxwell's and Maxwell-Garnett's theories, extended to higher volume fractions using Bruggeman's unsymmetrical treatment (BUT), with a long term goal of extending the treatment to mixtures more representative of real materials in order to calculate their effective electrical conductivity. The development accounts for spheroid shaped inclusions of varying degrees of anisotropic orientation. The orientation is described by the introduction of a distribution function. Two methodologies valid for the inclusion dilute limit were used to evaluate the effective conductivity: one based on Maxwell's far field approach, and the other based on the Maxwell-Garnett in the matrix approach. It was found that while the dilute limit equations for the effective conductivity were different, the final EMT equations derived by applying BUT collapsed to the same formula which was generalized for anisotropic orientation based on the distribution function presented.

  4. Cool Pool development. Quarterly technical report No. 3, July 1-September 30, 1980

    SciTech Connect

    Batts, D.

    1980-09-01

    The Cool Pool is a shaded evaporating pool that is connected to thermal mass storage in a thermosyphon configuration. The system requires no moveable insulation. The pool is placed outside a building, and the thermal mass, vertical tubes full of water, are inside the living space. The pool must be elevated so that its water level is as high or higher than the water level in the tubes for thermosyphoning to work properly. The pool is shaded to prevent heating by direct solar radiation. A schematic of the Cool Pool is shown and how it works is described. Tests performed at Living Systems at Winters, California and analytical results are discussed.

  5. Large effective-area fibers

    NASA Astrophysics Data System (ADS)

    Safaai-Jazi, Ahmad; Hattori, H. T.; Baghdadi, J. A.

    1999-04-01

    Refractive-index nonlinearities have negligible effect on the performance of short-haul fiber-optic communication links utilizing electronic repeaters. However, in long optical fiber links, nonlinearities can cause severe signal degradations. To mitigate nonlinear effects, new generation of fibers, referred to as large effective-area fibers, have been introduced in recent years. This paper reviews the latest research and development work on these fibers conducted by several research groups around the world. Attention is focused on a class of large effective-area fibers that are based on a depressed-core multiple-cladding design. Transmission properties, including dispersion, dispersion slope, effective area, mode-field diameter, bending loss, polarization-mode dispersion, and cutoff wavelength are discussed. Dispersion-shifted, non-zero dispersion-shifted, and dispersion-flattened designs are addressed. Design optimization, particularly with regard to effective area, bending loss, and polarization-mode dispersion, is elaborated upon. The trade-off between effective-area and bending loss is emphasized. Results for dispersion-shifted and non-zero dispersion-shifted large effective-area fibers with zero polarization-mode dispersion and low bending loss at 1.55 micrometer wavelength are presented.

  6. Evolution of maternal effect senescence

    PubMed Central

    Moorad, Jacob A.; Nussey, Daniel H.

    2016-01-01

    Increased maternal age at reproduction is often associated with decreased offspring performance in numerous species of plants and animals (including humans). Current evolutionary theory considers such maternal effect senescence as part of a unified process of reproductive senescence, which is under identical age-specific selective pressures to fertility. We offer a novel theoretical perspective by combining William Hamilton’s evolutionary model for aging with a quantitative genetic model of indirect genetic effects. We demonstrate that fertility and maternal effect senescence are likely to experience different patterns of age-specific selection and thus can evolve to take divergent forms. Applied to neonatal survival, we find that selection for maternal effects is the product of age-specific fertility and Hamilton’s age-specific force of selection for fertility. Population genetic models show that senescence for these maternal effects can evolve in the absence of reproductive or actuarial senescence; this implies that maternal effect aging is a fundamentally distinct demographic manifestation of the evolution of aging. However, brief periods of increasingly beneficial maternal effects can evolve when fertility increases with age faster than cumulative survival declines. This is most likely to occur early in life. Our integration of theory provides a general framework with which to model, measure, and compare the evolutionary determinants of the social manifestations of aging. Extension of our maternal effects model to other ecological and social contexts could provide important insights into the drivers of the astonishing diversity of lifespans and aging patterns observed among species. PMID:26715745

  7. Cell cycle effects of drugs

    SciTech Connect

    Dethlefsen, L.A.

    1986-01-01

    This book contains 11 chapters. Some of the chapter titles are: Cell Growth and Division Cycle; Cell Cycle Effects of Alkylating Agents; Biological Effects of Folic Acid Antagonists with Antineoplastic Activity; and Bleomycin-Mode of Action with Particular Reference to the Cell Cycle.

  8. Tritrophic Effects in Bt Cotton

    ERIC Educational Resources Information Center

    Gutierrez, Andrew Paul

    2005-01-01

    Transgenic insecticidal Bt crops are being increasingly used worldwide, and concern is increasing about resistance and their effects on nontarget organisms. The toxin acts as a weak pesticide and, hence, the effects are subtler than those of chemical biocides. However, the toxin is ever present, but concentrations vary with age of plant and plant…

  9. Pharmacological effects on sexual function.

    PubMed

    Carey, J Chris

    2006-12-01

    Many drugs may have effects on sexual function. Sexual function is complex and psychological and relationship issues are likely to have greater impacts on sexual function in women than drugs. Although it is important to understand the effects of drugs on sexual function, physicians should use caution in "medicalization" of sexual function in women [106]. PMID:17116504

  10. Gestalt Effect of Self Assessment

    ERIC Educational Resources Information Center

    McDonald, Betty

    2012-01-01

    Defining self assessment as the involvement of students in identifying standards and/or criteria to apply to their work and making judgements about the extent to which they have met these criteria and standards, this paper seeks to highlight the gestalt effect of self assessment. The total effect of self assessment on the learner is greater than…

  11. Teacher Evaluation: Archiving Teaching Effectiveness

    ERIC Educational Resources Information Center

    Nielsen, Lance D.

    2014-01-01

    Teacher evaluation is a current hot topic within music education. This article offers strategies for K-12 music educators on how to promote their effectiveness as teachers through archival documentation in a teacher portfolio. Using the Danielson evaluation model (based on four domains of effective teaching practices), examples of music teaching…

  12. Superconducting Field-Effect Transistors

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Romanofsky, Robert R.; Tabib-Azar, Massood

    1995-01-01

    Devices offer switching speeds greater than semiconducting counterparts. High-Tc superconducting field-effect transistors (SUPEFETs) investigated for use as electronic switches in delay-line-type microwave phase shifters. Resemble semiconductor field-effect transistors in some respects, but their operation based on different principle; namely, electric-field control of transition between superconductivity and normal conductivity.

  13. Cumulative effects analysis (CEA) tools

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective rangeland management requires careful consideration of the possible cumulative effects of different management options prior to making major management decisions. State-and-transition (S/T) models, based on ecological sites, capture our understanding ecosystem functioning and can be used t...

  14. Classroom Composition and Peer Effects

    ERIC Educational Resources Information Center

    Hattie, John A. C.

    2002-01-01

    This chapter examines the extent to which the composition of classes affects learning outcomes. The aim is to explore peer effects when students are organized into classes on the basis of ability, ethnicity, or gender, as well as the effects of multigrade and multi-age classes and class size. The argument is defended that these composition factors…

  15. Tritrophic Effects in Bt Cotton

    ERIC Educational Resources Information Center

    Gutierrez, Andrew Paul

    2005-01-01

    Transgenic insecticidal Bt crops are being increasingly used worldwide, and concern is increasing about resistance and their effects on nontarget organisms. The toxin acts as a weak pesticide and, hence, the effects are subtler than those of chemical biocides. However, the toxin is ever present, but concentrations vary with age of plant and plant…

  16. The Effectiveness of Early Intervention.

    ERIC Educational Resources Information Center

    Guralnick, Michael J., Ed.

    This book reviews research on the effectiveness of early intervention for children with disabilities or who are at risk. Program factors for children at risk and with disabilities, the effects of early intervention on different types of disabilities, and the outcomes of early intervention are explored. Chapters include: "Second-Generation Research…

  17. Teaching the Photoelectric Effect Inductively

    ERIC Educational Resources Information Center

    Sokolowski, Andrzej

    2013-01-01

    Research has shown that students have difficulty understanding the underlying process of the photoelectric effect. Thus, this study sought to utilize an inductively situated lesson for teaching the photoelectric effect, hypothesizing that this type of enquiry would help learners delve deeper into the principles of the phenomenon and provide a…

  18. Spectral effects in radiation embrittlement

    SciTech Connect

    Farrell, K.; Mansur, L.K.

    1991-01-01

    It has long been suspected that radiation effects such as embrittlement might depend not only on the total neutron exposure and temperature but also on the neutron flux and the neutron spectrum. This paper describes two describes effects of neutron spectra.

  19. Spectral effects in radiation embrittlement

    SciTech Connect

    Farrell, K.; Mansur, L.K.

    1991-12-31

    It has long been suspected that radiation effects such as embrittlement might depend not only on the total neutron exposure and temperature but also on the neutron flux and the neutron spectrum. This paper describes two describes effects of neutron spectra.

  20. Teaching the Photoelectric Effect Inductively

    ERIC Educational Resources Information Center

    Sokolowski, Andrzej

    2013-01-01

    Research has shown that students have difficulty understanding the underlying process of the photoelectric effect. Thus, this study sought to utilize an inductively situated lesson for teaching the photoelectric effect, hypothesizing that this type of enquiry would help learners delve deeper into the principles of the phenomenon and provide a…

  1. Counselor Effectiveness Through Radio Communication.

    ERIC Educational Resources Information Center

    Tentoni, Stuart C.

    This study determined the effectiveness of the use of radio as a means of providing immediate feedback on student counselors in a practicum setting. Using a non-equivalent group experimental design, 10 experimental subjects were compared to 10 control subjects with respect to counselor effectiveness. The experimental subjects were given immediate…

  2. Effects of Ritalin on Reading.

    ERIC Educational Resources Information Center

    Cooter, Robert B., Jr.

    1988-01-01

    This article describes the use of "Ritalin" to calm overactive children. The drug's side effects are reported, and research on the effect of "Ritalin" on reading performance in the classroom is reviewed. It is concluded that use of stimulant drugs to help reading underachievers is not supported by research. (Author/JDD)

  3. Student Perceptions of University Effectiveness.

    ERIC Educational Resources Information Center

    Kleemann, Gary L.; Richardson, Richard C., Jr.

    Student perceptions of the effectiveness of three state universities was studied: Arizona State University, University of Arizona, and Northern Arizona University. An operational definition of effectiveness was proposed based on the literature, and a list of organizational activities was validated by administrators, faculty, community…

  4. Evolution of maternal effect senescence.

    PubMed

    Moorad, Jacob A; Nussey, Daniel H

    2016-01-12

    Increased maternal age at reproduction is often associated with decreased offspring performance in numerous species of plants and animals (including humans). Current evolutionary theory considers such maternal effect senescence as part of a unified process of reproductive senescence, which is under identical age-specific selective pressures to fertility. We offer a novel theoretical perspective by combining William Hamilton's evolutionary model for aging with a quantitative genetic model of indirect genetic effects. We demonstrate that fertility and maternal effect senescence are likely to experience different patterns of age-specific selection and thus can evolve to take divergent forms. Applied to neonatal survival, we find that selection for maternal effects is the product of age-specific fertility and Hamilton's age-specific force of selection for fertility. Population genetic models show that senescence for these maternal effects can evolve in the absence of reproductive or actuarial senescence; this implies that maternal effect aging is a fundamentally distinct demographic manifestation of the evolution of aging. However, brief periods of increasingly beneficial maternal effects can evolve when fertility increases with age faster than cumulative survival declines. This is most likely to occur early in life. Our integration of theory provides a general framework with which to model, measure, and compare the evolutionary determinants of the social manifestations of aging. Extension of our maternal effects model to other ecological and social contexts could provide important insights into the drivers of the astonishing diversity of lifespans and aging patterns observed among species. PMID:26715745

  5. Effect Size in Clinical Phonology

    ERIC Educational Resources Information Center

    Gierut, Judith A.; Morrisette, Michele L.

    2011-01-01

    The purpose of this article is to motivate the use of effect size (ES) for single-subject research in clinical phonology, with an eye towards meta-analyses of treatment effects for children with phonological disorders. Standard mean difference (SMD) is introduced and illustrated as one ES well suited to the multiple baseline (MBL) design and…

  6. Effective Vocal Production in Performance.

    ERIC Educational Resources Information Center

    King, Robert G.

    If speech instructors are to teach students to recreate for an audience an author's intellectual and emotional meanings, they must teach them to use human voice effectively. Seven essential elements of effective vocal production that often pose problems for oral interpretation students should be central to any speech training program: (1)…

  7. Alcohol's Effects on the Body

    MedlinePLUS

    ... Your Health » Alcohol's Effects on the Body Alcohol's Effects on the Body Drinking too much – on a single occasion or over time – can take a serious toll on your health. Here’s how alcohol can affect your body: Brain: Alcohol interferes with the brain’s communication pathways, and ...

  8. Hiring Effective Secondary School Counselors

    ERIC Educational Resources Information Center

    McGlothlin, Jason M.; Miller, Lynne Guillot

    2008-01-01

    Today's effective school counselors are integral in education reform, school leadership, and student achievement. It is typically the responsibility of building principals to hire effective school counselors. This article builds on previous literature and provides principals with questions to ask and information to gather that may be helpful in…

  9. Evaluations of the Overjustification Effect

    ERIC Educational Resources Information Center

    Peters, Kerri P.; Vollmer, Timothy R.

    2014-01-01

    The utility of reinforcement-based procedures has been well established in the behavior analysis literature and is commonly used in educational settings. However, the overjustification effect is one commonly cited criticism of programs that use tangible items as reinforcers. In the current studies, we evaluated the effects of tangible rewards…

  10. Effective Schools: Mirror or Mirage?

    ERIC Educational Resources Information Center

    Tomlinson, Tommy M.

    1981-01-01

    Identifies and analyzes characteristics which are frequently mentioned as contributing to effective schools. Among the characteristics are that they improve the effectiveness and efficiency of students' work by organizing material and/or instruction, increase the amount of work students perform per unit of time, reduce distractions, and encourage…

  11. Cost-Effective National Schemes.

    ERIC Educational Resources Information Center

    Lacson, Jose D.

    Facilities and schemes for training and retraining vocational education teachers are needed in developed and developing countries, but such training must be cost-effective. Some characteristics of cost-effective schemes include the following: adaptability, coordination between various providers, good planning, and adequate financial support.…

  12. Space environment effects (M0006)

    NASA Technical Reports Server (NTRS)

    Angelo, J. A., Jr.; Madonna, R. G.; Altadonna, L. P.; Dagostino, M. D.; Chang, J. Y.; Alfano, R. R.; Caplan, V. L.

    1984-01-01

    The effects of long term exposure to the near Earth space environment on advanced electrooptical and radiation sensor components were examined. The effect of long duration spaceflight on the germination rate of selected terrestrial plant seeds is observed in exobiological experiments.

  13. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-08-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  14. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-01-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  15. Teacher Evaluation: Archiving Teaching Effectiveness

    ERIC Educational Resources Information Center

    Nielsen, Lance D.

    2014-01-01

    Teacher evaluation is a current hot topic within music education. This article offers strategies for K-12 music educators on how to promote their effectiveness as teachers through archival documentation in a teacher portfolio. Using the Danielson evaluation model (based on four domains of effective teaching practices), examples of music teaching…

  16. The Effectiveness of Early Intervention.

    ERIC Educational Resources Information Center

    Guralnick, Michael J., Ed.

    This book reviews research on the effectiveness of early intervention for children with disabilities or who are at risk. Program factors for children at risk and with disabilities, the effects of early intervention on different types of disabilities, and the outcomes of early intervention are explored. Chapters include: "Second-Generation Research…

  17. Herbicide Effects on Plant Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of herbicides on plant disease is an important, but generally overlooked, aspect of integrated pest management. Furthermore, these interactions can be crucial contributors to the success or failure of the biocontrol of weeds with microbes. Indirectly, through their strong effects on pla...

  18. Correlation effects and bound states

    SciTech Connect

    Zinovjev, G. M.; Molodtsov, S. V.

    2012-11-15

    Bound states in a simple quark model that are due to correlation effects are analyzed. The confining properties of this model in meson (quark-antiquark and diquark) channels manifest themselves at any quark momenta, and an extra potential field may only enhance the confining effect.

  19. Retrieval Effectiveness on the Web.

    ERIC Educational Resources Information Center

    Savoy, Jacques; Picard, Justin

    2001-01-01

    Discusses the role of search engines in Web usability and analyzes and evaluates the retrieval effectiveness of various indexing and searching strategies on a new Web text collection. Highlights include preprocessing techniques that might improve retrieval effectiveness; and hyperlinks as useful sources of evidence in improving retrieval…

  20. Importance of Effective Listening Infomercial

    ERIC Educational Resources Information Center

    Johnson-Curiskis, Nanette

    2009-01-01

    This article details an activity intended for use in a course with a unit on effective listening, including listening courses, public speaking, and interpersonal communication. Students will explain the importance of effective and active listening for a target audience by producing an infomercial for a product or service which they design.

  1. Switchgrass biochar effects two aridisols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of biochar has received growing attention with regards to improving the physico-chemical properties of highly weathered Ultisols and Oxisols, yet very little research has focused on effects in Aridisols. The objective of this study was to investigate the effect of either low or high tempera...

  2. How Principals Support Teacher Effectiveness

    ERIC Educational Resources Information Center

    Gallagher, Michael

    2012-01-01

    The current standards and accountability regime describes effective teaching as the ability to increase student achievement on standardized tests. This narrow definition of effectiveness can lead principals to create school cultures myopically focused on student achievement data. A "laser-like focus on academic achievement," if employed too…

  3. Clinical side effects during aerosol therapy: cutaneous and ocular effects.

    PubMed

    Geller, David E

    2007-01-01

    Aerosolized medications maximize clinical benefit by targeting the airways and minimize side effects by reducing (though not eliminating) systemic exposure. Aerosolized drugs delivered with a facemask may inadvertently deposit on the face and in the eyes, raising concerns about cutaneous and ocular side effects with these drugs. Cases of anisocoria have been reported from exposure of the eyes to aerosol bronchodilators. Whether inhaled corticosteroids (ICS) can cause skin and eye problems like those seen with systemic or topical steroids is more difficult to answer. Patients who take ICS may have other corticosteroid exposures, or have other conditions that predispose them to side effects, making the analysis of the ICS risk challenging. Also, many studies were not designed to search for cutaneous or ocular effects, or may have been too short to detect these effects. Nevertheless, ICS have been associated with an increased risk of skin thinning, bruising, cataracts and possibly glaucoma in adults, but not in children. The risks increase with advanced age, higher doses, and longer duration of use. In children, the risks of cataracts and glaucoma were negligible with ICS, whether a mouthpiece or a mask interface was used. Side effects like skin rash and conjunctivitis occurred at low frequencies similar to placebo or comparator drugs. We do not know whether exposed children will have increased risks from ICS later in life. Therefore, it is wise to avoid face and eye deposition when possible, and to use the minimally effective dose. PMID:17411401

  4. Nursing education and job effectiveness.

    PubMed

    McCloskey, J C

    1983-01-01

    The purpose of this multiple regression study was to determine whether nurses with different educational preparation differ in job effectiveness. The dependent variable job effectiveness was ascertained by asking head nurses to rate their staff nurses on job effectiveness by comparing them to each other and to ideal best and worst possible nurses. Job effectiveness was not defined; rather, a profile of the effective nurse was constructed from the study data. Questionnaire data were analyzed for 299 staff nurses (75 percent return): 53 practical nurses, 63 associate degree nurses, 134 diploma nurses and 49 baccalaureate nurses. The sample was obtained from 52 units located in 12 Chicago area hospitals chosen randomly from a stratified list. PMID:6549845

  5. Psychological predictors of astronaut effectiveness.

    PubMed

    Rose, R M; Fogg, L F; Helmreich, R L; McFadden, T J

    1994-10-01

    Are the personality characteristics of astronauts related to their professional effectiveness? In order to answer this question, effectiveness and personality data were collected from 65 NASA astronauts. Several findings emerged from these data. Five personality subscales were related to effectiveness in one form or another. They were: high Negative Expressivity and Negative Communion (subordinate and gullible), low Impatience and Irritability, low Openness (to new ideas and experiences), low Negative Instrumentality (egoism) and high Agreeableness. Examining the graphs of these relationships indicated that they were not linear. This examination indicated that high levels on these undesirable personality characteristics (e.g., Impatience/Irritability) were distributed across all levels of effectiveness. Low levels of the undesirable personality characteristics were found only among the most effective astronauts. We concluded that these other-directed personality qualities will assume increasing importance in long-term spaceflight, and consequently, should be the focus of greater attention in future astronaut selection and training. PMID:7832732

  6. Antimicrobial effects of silver nanoparticles.

    PubMed

    Kim, Jun Sung; Kuk, Eunye; Yu, Kyeong Nam; Kim, Jong-Ho; Park, Sung Jin; Lee, Hu Jang; Kim, So Hyun; Park, Young Kyung; Park, Yong Ho; Hwang, Cheol-Yong; Kim, Yong-Kwon; Lee, Yoon-Sik; Jeong, Dae Hong; Cho, Myung-Haing

    2007-03-01

    The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of Ag nanoparticles on microorganisms and antimicrobial mechanism have not been revealed clearly. Stable Ag nanoparticles were prepared and their shape and size distribution characterized by particle characterizer and transmission electron microscopic study. The antimicrobial activity of Ag nanoparticles was investigated against yeast, Escherichia coli, and Staphylococcus aureus. In these tests, Muller Hinton agar plates were used and Ag nanoparticles of various concentrations were supplemented in liquid systems. As results, yeast and E. coli were inhibited at the low concentration of Ag nanoparticles, whereas the growth-inhibitory effects on S. aureus were mild. The free-radical generation effect of Ag nanoparticles on microbial growth inhibition was investigated by electron spin resonance spectroscopy. These results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems. PMID:17379174

  7. Media Effects: Theory and Research.

    PubMed

    Valkenburg, Patti M; Peter, Jochen; Walther, Joseph B

    2016-01-01

    This review analyzes trends and commonalities among prominent theories of media effects. On the basis of exemplary meta-analyses of media effects and bibliometric studies of well-cited theories, we identify and discuss five features of media effects theories as well as their empirical support. Each of these features specifies the conditions under which media may produce effects on certain types of individuals. Our review ends with a discussion of media effects in newer media environments. This includes theories of computer-mediated communication, the development of which appears to share a similar pattern of reformulation from unidirectional, receiver-oriented views, to theories that recognize the transactional nature of communication. We conclude by outlining challenges and promising avenues for future research. PMID:26331344

  8. [Indirect effects of cytomegalovirus infection].

    PubMed

    Castón Osorio, Juan José; Zurbano Gońi, Felipe

    2011-12-01

    Despite improvements in prevention strategies, cytomegalovirus (CMV) continues to be the main cause of infection in solid organ transplant recipients. In these patients, in addition to direct effects, such as viral syndrome or invasive organ disease, CMV can cause indirect effects resulting from the interaction of the virus with the host's immune system. This interaction may increase immunosuppression, with a consequent rise in opportunistic infections and the risk of malignancies (Epstein-Barr virus-associated posttransplantation lymphoproliferative disease) and graft dysfunction. Currently, a direct causal relation between CMV and most of the indirect effects described cannot be established. However, numerous experimental and clinical studies have found an association between the development of these effects and CMV. Moreover, some of these effects, such as the development of opportunistic infections, have been reduced by CMV prophylaxis. PMID:22541915

  9. Synaptic Effects Induced by Alcohol

    PubMed Central

    Roberto, Marisa

    2016-01-01

    Ethanol (EtOH) has effects on numerous cellular molecular targets, and alterations in synaptic function are prominent among these effects. Acute exposure to EtOH activates or inhibits the function of proteins involved in synaptic transmission, while chronic exposure often produces opposing and/or compensatory/homeostatic effects on the expression, localization, and function of these proteins. Interactions between different neurotransmitters (e.g., neuropeptide effects on release of small molecule transmitters) can also influence both acute and chronic EtOH actions. Studies in intact animals indicate that the proteins affected by EtOH also play roles in the neural actions of the drug, including acute intoxication, tolerance, dependence, and the seeking and drinking of EtOH. This chapter reviews the literature describing these acute and chronic synaptic effects of EtOH and their relevance for synaptic transmission, plasticity, and behavior. PMID:21786203

  10. Enhanced Evaporation Strength through Fast Water Permeation in Graphene-Oxide Deposition.

    PubMed

    Tong, Wei Li; Ong, Wee-Jun; Chai, Siang-Piao; Tan, Ming K; Hung, Yew Mun

    2015-01-01

    The unique characteristic of fast water permeation in laminated graphene oxide (GO) sheets has facilitated the development of ultrathin and ultrafast nanofiltration membranes. Here we report the application of fast water permeation property of immersed GO deposition for enhancing the performance of a GO/water nanofluid charged two-phase closed thermosyphon (TPCT). By benchmarking its performance against a silver oxide/water nanofluid charged TPCT, the enhancement of evaporation strength is found to be essentially attributed to the fast water permeation property of GO deposition instead of the enhanced surface wettability of the deposited layer. The expansion of interlayer distance between the graphitic planes of GO deposited layer enables intercalation of bilayer water for fast water permeation. The capillary force attributed to the frictionless interaction between the atomically smooth, hydrophobic carbon structures and the well-ordered hydrogen bonds of water molecules is sufficiently strong to overcome the gravitational force. As a result, a thin water film is formed on the GO deposited layers, inducing filmwise evaporation which is more effective than its interfacial counterpart, appreciably enhanced the overall performance of TPCT. This study paves the way for a promising start of employing the fast water permeation property of GO in thermal applications. PMID:26100977

  11. Enhanced Evaporation Strength through Fast Water Permeation in Graphene-Oxide Deposition

    PubMed Central

    Li Tong, Wei; Ong, Wee-Jun; Chai, Siang-Piao; Tan, Ming K.; Mun Hung, Yew

    2015-01-01

    The unique characteristic of fast water permeation in laminated graphene oxide (GO) sheets has facilitated the development of ultrathin and ultrafast nanofiltration membranes. Here we report the application of fast water permeation property of immersed GO deposition for enhancing the performance of a GO/water nanofluid charged two-phase closed thermosyphon (TPCT). By benchmarking its performance against a silver oxide/water nanofluid charged TPCT, the enhancement of evaporation strength is found to be essentially attributed to the fast water permeation property of GO deposition instead of the enhanced surface wettability of the deposited layer. The expansion of interlayer distance between the graphitic planes of GO deposited layer enables intercalation of bilayer water for fast water permeation. The capillary force attributed to the frictionless interaction between the atomically smooth, hydrophobic carbon structures and the well-ordered hydrogen bonds of water molecules is sufficiently strong to overcome the gravitational force. As a result, a thin water film is formed on the GO deposited layers, inducing filmwise evaporation which is more effective than its interfacial counterpart, appreciably enhanced the overall performance of TPCT. This study paves the way for a promising start of employing the fast water permeation property of GO in thermal applications. PMID:26100977

  12. Heat Pipe-Assisted Thermoelectric Power Generation Technology for Waste Heat Recovery

    NASA Astrophysics Data System (ADS)

    Jang, Ju-Chan; Chi, Ri-Guang; Rhi, Seok-Ho; Lee, Kye-Bock; Hwang, Hyun-Chang; Lee, Ji-Su; Lee, Wook-Hyun

    2015-06-01

    Currently, large amounts of thermal energy dissipated from automobiles are emitted through hot exhaust pipes. This has resulted in the need for a new efficient recycling method to recover energy from waste hot exhaust gas. The present experimental study investigated how to improve the power output of a thermoelectric generator (TEG) system assisted by a wickless loop heat pipe (loop thermosyphon) under the limited space of the exhaust gas pipeline. The present study shows a novel loop-type heat pipe-assisted TEG concept to be applied to hybrid vehicles. The operating temperature of a TEG's hot side surface should be as high as possible to maximize the Seebeck effect. The present study shows a novel TEG concept of transferring heat from the source to the sink. This technology can transfer waste heat to any local place with a loop-type heat pipe. The present TEG system with a heat pipe can transfer heat and generate an electromotive force power of around 1.3 V in the case of 170°C hot exhaust gas. Two thermoelectric modules (TEMs) for a conductive block model and four Bi2Te3 TEMs with a heat pipe-assisted model were installed in the condenser section. Heat flows to the condenser section from the evaporator section connected to the exhaust pipe. This novel TEG system with a heat pipe can be placed in any location on an automobile.

  13. Enhanced Evaporation Strength through Fast Water Permeation in Graphene-Oxide Deposition

    NASA Astrophysics Data System (ADS)

    Li Tong, Wei; Ong, Wee-Jun; Chai, Siang-Piao; Tan, Ming K.; Mun Hung, Yew

    2015-06-01

    The unique characteristic of fast water permeation in laminated graphene oxide (GO) sheets has facilitated the development of ultrathin and ultrafast nanofiltration membranes. Here we report the application of fast water permeation property of immersed GO deposition for enhancing the performance of a GO/water nanofluid charged two-phase closed thermosyphon (TPCT). By benchmarking its performance against a silver oxide/water nanofluid charged TPCT, the enhancement of evaporation strength is found to be essentially attributed to the fast water permeation property of GO deposition instead of the enhanced surface wettability of the deposited layer. The expansion of interlayer distance between the graphitic planes of GO deposited layer enables intercalation of bilayer water for fast water permeation. The capillary force attributed to the frictionless interaction between the atomically smooth, hydrophobic carbon structures and the well-ordered hydrogen bonds of water molecules is sufficiently strong to overcome the gravitational force. As a result, a thin water film is formed on the GO deposited layers, inducing filmwise evaporation which is more effective than its interfacial counterpart, appreciably enhanced the overall performance of TPCT. This study paves the way for a promising start of employing the fast water permeation property of GO in thermal applications.

  14. Pulsating Heat pipe Only for Space (PHOS): results of the REXUS 18 sounding rocket campaign

    NASA Astrophysics Data System (ADS)

    Creatini, F.; Guidi, G. M.; Belfi, F.; Cicero, G.; Fioriti, D.; Di Prizio, D.; Piacquadio, S.; Becatti, G.; Orlandini, G.; Frigerio, A.; Fontanesi, S.; Nannipieri, P.; Rognini, M.; Morganti, N.; Filippeschi, S.; Di Marco, P.; Fanucci, L.; Baronti, F.; Mameli, M.; Manzoni, M.; Marengo, M.

    2015-11-01

    Two Closed Loop Pulsating Heat Pipes (CLPHPs) are tested on board REXUS 18 sounding rocket in order to obtain data over a relatively long microgravity period (approximately 90 s). The CLPHPs are partially filled with FC-72 and have, respectively, an inner tube diameter larger (3 mm) and slightly smaller (1.6 mm) than the critical diameter evaluated in static Earth gravity conditions. On ground, the small diameter CLPHP effectively works as a Pulsating Heat Pipe (PHP): the characteristic slug and plug flow pattern forms inside the tube and the heat exchange is triggered by thermally driven self-sustained oscillations of the working fluid. On the other hand, the large diameter CLPHP works as a two- phase thermosyphon in vertical position and doesn't work in horizontal position: in this particular condition, the working fluid stratifies within the device as the surface tension force is no longer able to balance buoyancy. Then, the idea to test the CLPHPs in reduced gravity conditions: as the gravity reduces the buoyancy forces becomes less intense and it is possible to recreate the typical PHP flow pattern also for larger inner tube diameters. This allows to increase the heat transfer rate and, consequently, to decrease the overall thermal resistance. Even though it was not possible to experience low gravity conditions due to a failure in the yoyo de-spin system, the thermal response to the peculiar acceleration field (hyper-gravity) experienced on board are thoroughly described.

  15. Longitudinal spin Seebeck effect free from the proximity Nernst effect.

    PubMed

    Kikkawa, T; Uchida, K; Shiomi, Y; Qiu, Z; Hou, D; Tian, D; Nakayama, H; Jin, X-F; Saitoh, E

    2013-02-01

    This Letter provides evidence for intrinsic longitudinal spin Seebeck effects (LSSEs) that are free from the anomalous Nernst effect (ANE) caused by an extrinsic proximity effect. We report the observation of LSSEs in Au/Y(3)Fe(5)O(12) (YIG) and Pt/Cu/YIG systems, showing that the LSSE appears even when the mechanism of the proximity ANE is clearly removed. In the conventional Pt/YIG structure, furthermore, we separate the LSSE from the ANE by comparing the voltages in different magnetization and temperature-gradient configurations; the ANE contamination was found to be negligibly small even in the Pt/YIG structure. PMID:23432302

  16. IMPROVING MEASURES OF BIOLOGIC EFFECT: MEASURING EFFECTS IN HUMAN MALES

    EPA Science Inventory

    Animal toxicology studies have demonstrated spermatogenesis and sperm quality effects after exposure to several drinking water disinfection byproducts (DBPs), including DCA, BDCM, chloral hydrate and DBA. Population-based field studies to identify human male reproductive risks o...

  17. Context Effects in Western Herbal Medicine: Fundamental to Effectiveness?

    PubMed

    Snow, James

    2016-01-01

    Western herbal medicine (WHM) is a complex healthcare system that uses traditional plant-based medicines in patient care. Typical preparations are individualized polyherbal formulae that, unlike herbal pills, retain the odor and taste of whole herbs. Qualitative studies in WHM show patient-practitioner relationships to be collaborative. Health narratives are co-constructed, leading to assessments, and treatments with personal significance for participants. It is hypothesized that the distinct characteristics of traditional herbal preparations and patient-herbalist interactions, in conjunction with the WHM physical healthcare environment, evoke context (placebo) effects that are fundamental to the overall effectiveness of herbal treatment. These context effects may need to be minimized to demonstrate pharmacological efficacy of herbal formulae in randomized, placebo-controlled trials, optimized to demonstrate effectiveness of WHM in pragmatic trials, and consciously harnessed to enhance outcomes in clinical practice. PMID:26613625

  18. IMPROVING MEASURES OF BIOLOGIC EFFECT: MEASURING EFFECTS IN HUMAN MALES.

    EPA Science Inventory

    Animal toxicology studies have demonstrated spermatogenesis and sperm quality effects after exposure to DCA, BDCM, chloral hydrate and DBA. Population-based field studies to identify human male reproductive risks of DBPs require preliminary work to develop specific epidemiologi...

  19. Placebo and nocebo effects on itch: effects, mechanisms, and predictors.

    PubMed

    Bartels, Danielle J P; van Laarhoven, Antoinette I M; van de Kerkhof, Peter C M; Evers, Andrea W M

    2016-01-01

    Placebo and nocebo effects have been extensively studied in the field of pain and more recently also on itch. In accordance with placebo research on pain, expectancy learning via verbal suggestion or conditioning has shown to induce placebo and nocebo effects on itch, in which the combination of both procedures seems most promising. Moreover, itch can also be transferred 'contagiously' in which suggestion and social behavioural learning seem to play a role. With regard to predictors of placebo and nocebo responding on itch and contagious itch, preliminary evidence suggests a role for individual psychological characteristics and personality traits regarding negative outcome expectancies. Although findings on placebo and nocebo effects on itch seem comparable to pain, we have only just begun to understand the underlying mechanisms and predictors of placebo and nocebo effects on itch. PMID:26417885

  20. Mitigation of Space Radiation Effects

    NASA Astrophysics Data System (ADS)

    Atwell, William

    2012-02-01

    During low earth orbit and deep space missions, humans and spacecraft systems are exposed to high energy particles emanating from basically three sources: geomagnetically-trapped protons and electrons (Van Allen Belts), extremely high energy galactic cosmic radiation (GCR), and solar proton events (SPEs). The particles can have deleterious effects if not properly shielded. For humans, there can be a multitude of harmful effects depending on the degree of exposure. For spacecraft systems, especially electronics, the effects can range from single event upsets (SEUs) to catastrophic effects such as latchup and burnout. In addition, some materials, radio-sensitive experiments, and scientific payloads are subject to harmful effects. To date, other methods have been proposed such as electrostatic and electromagnetic shielding, but these approaches have not proven feasible due to cost, weight, and safety issues. The only method that has merit and has been effective is bulk or parasitic shielding. In this paper, we discuss in detail the sources of the space radiation environment, spacecraft, human, and onboard systems modeling methodologies, transport of these particles through shielding materials, and the calculation of the dose effects. In addition, a review of the space missions to date and a discussion of the space radiation mitigation challenges for lunar and deep space missions such as lunar outposts and human missions to Mars are presented.

  1. Late effects from hadron therapy

    SciTech Connect

    Blakely, Eleanor A.; Chang, Polly Y.

    2004-06-01

    Successful cancer patient survival and local tumor control from hadron radiotherapy warrant a discussion of potential secondary late effects from the radiation. The study of late-appearing clinical effects from particle beams of protons, carbon, or heavier ions is a relatively new field with few data. However, new clinical information is available from pioneer hadron radiotherapy programs in the USA, Japan, Germany and Switzerland. This paper will review available data on late tissue effects from particle radiation exposures, and discuss its importance to the future of hadron therapy. Potential late radiation effects are associated with irradiated normal tissue volumes at risk that in many cases can be reduced with hadron therapy. However, normal tissues present within hadron treatment volumes can demonstrate enhanced responses compared to conventional modes of therapy. Late endpoints of concern include induction of secondary cancers, cataract, fibrosis, neurodegeneration, vascular damage, and immunological, endocrine and hereditary effects. Low-dose tissue effects at tumor margins need further study, and there is need for more acute molecular studies underlying late effects of hadron therapy.

  2. Maxwell-Garnett effective medium theory: Quantum nonlocal effects

    SciTech Connect

    Moradi, Afshin

    2015-04-15

    We develop the Maxwell-Garnett theory for the effective medium approximation of composite materials with metallic nanoparticles by taking into account the quantum spatial dispersion effects in dielectric response of nanoparticles. We derive a quantum nonlocal generalization of the standard Maxwell-Garnett formula, by means the linearized quantum hydrodynamic theory in conjunction with the Poisson equation as well as the appropriate additional quantum boundary conditions.

  3. The Effective School Process: Alive and Well.

    ERIC Educational Resources Information Center

    Taylor, Barbara O.

    2002-01-01

    Discusses status of effective-school movement, especially the work of the National Alliance for Effective Schools and those who developed the Effective Schools Process. Lists six correlates of effective schools. (PKP)

  4. Paramagnetic Meissner effect in Nb

    SciTech Connect

    Kostic, P.; Veal, B.; Paulikas, A.P.; Welp, U.; Todt, V.R.; Gu, C.; Geiser, U.; Williams, J.M.; Carlson, K.D.; Klemm, R.A.

    1996-01-01

    The paramagnetic Meissner effect (PME), or Wohlleben effect, in which the field-cooled magnetization of superconducting samples is paramagnetic below {ital T}{sub {ital c}}, has been reported to occur in some samples of a variety of high-{ital T}{sub {ital c}} cuprate superconductors. It has been proposed that the effect arose in granular hole-doped cuprates from current loops with {pi} phase shifts of the superconducting order parameter at some grain-boundary junctions. It is argued that such behavior would be expected to occur in a {ital d}-wave superconductor, but not in a conventional {ital s}-wave superconductor. To test this hypothesis, we have searched for the occurrence of the effect in Nb, and have confirmed a recent report by Minhaj {ital et} {ital al}. of its occurrence in some Nb samples. For these studies, the effects of stray fields and field gradients in the measurement volume of the superconducting quantum interference device magnetometer have been carefully considered to rule out the possibility that measurement artifacts might be responsible for the apparent paramagnetic behavior in Nb. The {ital M}({ital T}) and {ital M}({ital H}) curves obtained in Nb samples that show the PME also show remarkably strong resemblance to those curves reported for the cuprate materials exhibiting the PME. Evidence is presented that the effect arises from inhomogeneously trapped flux, and is strongly influenced by sample geometry and surface effects. These results suggest that, for the effect to be observable, {ital T}{sub {ital c}} on the sample surface must be different from the bulk {ital T}{sub {ital c}}. The occurrence of the PME in Nb strongly suggests that the observation of this effect is unrelated to {ital d}-wave superconductivity. {copyright} {ital 1996 The American Physical Society.}

  5. Large Matter Effects in ????? Oscillations

    NASA Astrophysics Data System (ADS)

    Gandhi, Raj; Ghoshal, Pomita; Goswami, Srubabati; Mehta, Poonam; Sankar, S. Uma

    2005-02-01

    We show that matter effects change the ????? oscillation probability by as much as 70% for certain ranges of energies and path lengths. Consequently, the ????? survival probability also undergoes large changes. A proper understanding of ?? survival rates must consider matter effects in P?? as well as P?e. We comment on (a) how these matter effects may be observed and the sign of ?31 determined in atmospheric neutrino measurements and at neutrino factories, and (b) how they lead to heightened sensitivity for small ?13.

  6. Interference effects in potential wells

    NASA Astrophysics Data System (ADS)

    Mullin, W. J.; Laloë, F.

    2015-05-01

    We propose using an array of potential wells as an interferometer in which the beam splitters are provided by tunneling during an appropriate time through the barrier between wells. This arrangement allows demonstration of generalized Hong-Ou-Mandel effects with multiple particles traversing one or several beam splitters. Other interferometer effects can occur, including a violation of the Bell-Clauser-Horne-Shimony-Holt form of the Bell inequality. With interactions, one sees various effects, including so-called fermionization, collective tunneling, and self-trapping.

  7. More on effective composite metrics

    NASA Astrophysics Data System (ADS)

    Heisenberg, Lavinia

    2015-07-01

    In this work we study different classes of effective composite metrics proposed in the context of one-loop quantum corrections in bimetric gravity. For this purpose we consider contributions of the matter loops in the form of cosmological constants and potential terms yielding two types of effective composite metrics. This guarantees a nice behavior at the quantum level. However, the theoretical consistency at the classical level needs to be ensured additionally. It turns out that among all these possible couplings, only one unique effective metric survives these criteria at the classical level.

  8. Environmental effects on spacecraft materials

    NASA Technical Reports Server (NTRS)

    Haffner, J. W.

    1989-01-01

    The effects on the natural space environments on materials are presented, which may be used for SDI applications. The current state-of-the-art knowledge of those effects was studied, and a literature search, a questionnaire mailing, and some visits to NASA and Air Force research facilities were performed. Phase 2 will be a study of what materials may be used for SDI applications and to what natural space environments they may be vulnerable. Deficiencies in knowledge of the effects of the natural space environments on these materials are to be identified and recommendations are to be made to eliminate these knowledge deficiencies.

  9. Pharmacological Effects of Rosa Damascena

    PubMed Central

    Boskabady, Mohammad Hossein; Shafei, Mohammad Naser; Saberi, Zahra; Amini, Somayeh

    2011-01-01

    Rosa damascena mill L., known as Gole Mohammadi in is one of the most important species of Rosaceae family flowers. R. damascena is an ornamental plant and beside perfuming effect, several pharmacological properties including anti-HIV, antibacterial, antioxidant, antitussive, hypnotic, antidiabetic, and relaxant effect on tracheal chains have been reported for this plant. This article is a comprehensive review on pharmacological effects of R. damascena. Online literature searches were performed using Medline, medex, Scopus, and Google Scholar websites backed to 1972 to identify researches about R. damascena. Searches also were done by going through the author's files and the bibliographies of all located papers. PMID:23493250

  10. Repetitive Stern-Gerlach effect

    SciTech Connect

    Hsueh, S.-Y.

    1990-03-13

    I show that two spin rotators 180{degree} apart may be desirable for the repetitive Stern-Gerlach effect. I also calculate the effect of depolarization resonance on the repetitive Stern-Gerlach effect. It is shown that to first order in resonance strength, we can avoid the imperfection resonance if the energy of the beam is at G{gamma} = n + 1/2. The time available for accumulating the Stern-Gerlach kick is then limited by the intrinsic resonance. 5 refs., 1 fig.

  11. Novel effects of nitric oxide

    NASA Technical Reports Server (NTRS)

    Davis, K. L.; Martin, E.; Turko, I. V.; Murad, F.

    2001-01-01

    Nitric oxide (NO), a simple free radical gas, elicits a surprisingly wide range of physiological and pathophysiological effects. NO interacts with soluble guanylate cyclase to evoke many of these effects. However, NO can also interact with molecular oxygen and superoxide radicals to produce reactive nitrogen species that can modify a number of macromolecules including proteins, lipids, and nucleic acids. NO can also interact directly with transition metals. Here, we have reviewed the non--3',5'-cyclic-guanosine-monophosphate-mediated effects of NO including modifications of proteins, lipids, and nucleic acids.

  12. Crowding Effects of Membrane Proteins

    PubMed Central

    Zhou, Huan-Xiang

    2009-01-01

    In cell membranes, membrane proteins occupy ?30% of the total surface area. Crowding effects similar to those in the solution phase are thus to be expected. In addition, there are crowding effects unique to proteins bound to the two-dimensional membranes, such as those exerted on the equilibration of a protein between two membrane orientations and on the redistribution of proteins between different locations in a cell membrane. This article aims to present a theoretical framework for understanding the various crowding effects within membranes. For illustration, the theory is used to analyze previously published experimental and simulation data. It is hoped that the article will encourage quantitative analyses in future experiments and spur systematic investigation of membrane crowding effects. PMID:19323472

  13. Antidepressants and the Placebo Effect

    PubMed Central

    Kirsch, Irving

    2014-01-01

    Antidepressants are supposed to work by fixing a chemical imbalance, specifically, a lack of serotonin in the brain. Indeed, their supposed effectiveness is the primary evidence for the chemical imbalance theory. But analyses of the published data and the unpublished data that were hidden by drug companies reveals that most (if not all) of the benefits are due to the placebo effect. Some antidepressants increase serotonin levels, some decrease it, and some have no effect at all on serotonin. Nevertheless, they all show the same therapeutic benefit. Even the small statistical difference between antidepressants and placebos may be an enhanced placebo effect, due to the fact that most patients and doctors in clinical trials successfully break blind. The serotonin theory is as close as any theory in the history of science to having been proved wrong. Instead of curing depression, popular antidepressants may induce a biological vulnerability making people more likely to become depressed in the future. PMID:25279271

  14. Health effects of smokeless tobacco

    SciTech Connect

    Not Available

    1986-02-28

    Pharmacologic and physiologic effects of snuff and chewing tobacco include the gamut of cardiovascular, endocrinologic, neurologic, and psychological effects that are associated with nicotine. A review of studies appearing in the scientific literature involving various populations and approaches indicates that the use of snuff or chewing tobacco is associated with a variety of serious adverse effects and especially with oral cancer. The studies suggest that snuff and chewing tobacco also may affect reproduction, longevity, the cardiovascular system, and oral health. The Council on Scientific Affairs concludes there is evidence demonstrating that use of snuff or chewing tobacco is associated with adverse health effects such as oral cancer, urges the implementation of well-planned and long-term studies that will further define the risks of using snuff and chewing tobacco, and recommends that the restrictions applying to the advertising of cigarettes also be applied to the advertising of snuff and chewing tobacco.

  15. Medical effects of ionizing radiation

    SciTech Connect

    Mettler, F.A. Jr.; Upton, A.C.

    1995-12-31

    This book provides insights into published data on radiation effects in an informative summary style that will be valuable to the clinician, research scientist and health physicist. Integrating all the issues surrounding medical radiation is challenging, but well met here. Especially noteworthy are the chapters on the direct acute effects of high-dose radiation and on dose-response models for carcinogenesis. References are up to date through 1994, but important research conducted in years past is also well covered. Topics range from basic principles of physics to hormesis. The chapters thus have something for everyone: genetic effects, carcinogenesis, acute high-dose effect, in utero exposure, interaction with other environmental or host factors, probability of causation and risk perception. The coverage of hard-to-find topics coupled with extensive references are unique strengths of this text.

  16. CONTAMINATED SEDIMENTS - ECOLOGICAL EFFECTS RESEARCH

    EPA Science Inventory

    NHEERL's research in this area focuses on ecological effects of bioaccumulative chemicals, such as PCBs. The research is designed with recognition that sites of different size and complexity require bioaccumulation models with correspondingly complex and/or extensive data requir...

  17. Psychological effects of thought acceleration.

    PubMed

    Pronin, Emily; Jacobs, Elana; Wegner, Daniel M

    2008-10-01

    Six experiments found that manipulations that increase thought speed also yield positive affect. These experiments varied in both the methods used for accelerating thought (i.e., instructions to brainstorm freely, exposure to multiple ideas, encouragement to plagiarize others' ideas, performance of easy cognitive tasks, narration of a silent video in fast-forward, and experimentally controlled reading speed) and the contents of the thoughts that were induced (from thoughts about money-making schemes to thoughts of five-letter words). The results suggested that effects of thought speed on mood are partially rooted in the subjective experience of thought speed. The results also suggested that these effects can be attributed to the joy-enhancing effects of fast thinking (rather than only to the joy-killing effects of slow thinking). This work is inspired by observations of a link between "racing thoughts" and euphoria in cases of clinical mania, and potential implications of that observed link are discussed. PMID:18837610

  18. Uterine inhibitory effect of reticuline.

    PubMed

    Martin, M L; Sagredo, J A; Morais, J M; Montero, M J; Sanchez, M T; San Roman, L

    1988-11-01

    Reticuline, the most abundant benzylisoquinoleic alkaloid of Laurobasidium lauri, exerts a uterine inhibitory effect mainly related to a decrease in the concentration of cytosolic calcium available for contraction. PMID:2907562

  19. Magnetic effects in anomalous dispersion

    SciTech Connect

    Blume, M.

    1992-12-31

    Spectacular enhancements of magnetic x-ray scattering have been predicted and observed experimentally. These effects are the result of resonant phenomena closely related to anomalous dispersion, and they are strongest at near-edge resonances. The theory of these resonances will be developed with particular attention to the symmetry properties of the scatterer. While the phenomena to be discussed concern magnetic properties the transitions are electric dipole or electric quadrupole in character and represent a subset of the usual anomalous dispersion phenomena. The polarization dependence of the scattering is also considered, and the polarization dependence for magnetic effects is related to that for charge scattering and to Templeton type anisotropic polarization phenomena. It has been found that the strongest effects occur in rare-earths and in actinides for M shell edges. In addition to the scattering properties the theory is applicable to ``forward scattering`` properties such as the Faraday effect and circular dichroism.

  20. Electromagnetically induced angular Talbot effect

    NASA Astrophysics Data System (ADS)

    Qiu, Tianhui; Yang, Guojian

    2015-12-01

    The discrete angular spectrum (angular Talbot effect) of a periodic grating illuminated by a suitable spherical wave front has been observed recently (Azańa and Chatellus 2104 Phys. Rev. Lett. 112 213902). In this paper we study the possibility of such a phenomenon being realized with a medium that has no macroperiodic structure itself. Tunable electromagnetically induced grating (EIG) could be such a kind of medium. We obtain an EIG based on the periodically modulated strong susceptibility due to the third-order nonlinear effect generated in a double ?-type four-level atomic system, and show the angular Talbot effect of an amplitude EIG, as well as a hybrid EIG, as the condition of the discrete phase-modulation shift of the illumination light front is satisfied. EIG parameters are tunable and the EIG-based angular Talbot effect may have the same potential applications as its periodic grating counterpart has.