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1

Laboratory investigations  

International Nuclear Information System (INIS)

Our task is to design mined-repository systems that will adequately secure high-level nuclear waste for at least 10,000 yr and that will be mechanically stable for 50 to 100-yr periods of retrievability during which mistakes could be corrected and a valuable source of energy could be reclaimed, should national policy on the reprocessing of spent fuel ever change. The only credible path for the escape of radionuclides from the repository to the biosphere is through ground-water, and in hard rock, bulk permeability is largely governed by natural and artificial fracture systems. Catastrophic failure of an excavation in hard rock is likely to occur at the weakest links - the discontinuities in the rock mass that is perturbed first by mining and then by radiogenic heating. The laboratory can contribute precise measurements of the pertinent thermomechanical, hydrological and chemical properties and improve our understanding of the fundamental processes through careful experiments under well controlled conditions that simulate the prototype environment. Thus laboratory investigations are necessary, but they are not sufficient, for conventional sample sizes are small relative to natural defects like joints - i.e., the rock mass is not a continuum - and test durations are short compared to those that predictive modeling must take into account. Laboratory investigators can contribute substantially more useful data if they are provided facilities for testing large specimens(say one cubic meter) and for creep testing of all candidate host rocks. Even so, extrapolations of laboratory data to the field in neither space nor time are valid without the firm theoretical foundations yet to be built. Meanwhile in-situ measurements of structure-sensitive physical properties and access to direct observations of rock-mass character will be absolutely necessary

1980-11-01

2

Experimental Investigation of Multibunch, Multipass Beam Breakup in the Jefferson Laboratory Free Electron Laser Upgrade Driver  

Energy Technology Data Exchange (ETDEWEB)

In recirculating accelerators, and in particular energy recovery linacs (ERLs), the maximum current can be limited by multipass, multibunch beam breakup (BBU), which occurs when the electron beam interacts with the higher-order modes (HOMs) of an accelerating cavity on the accelerating pass and again on the energy recovering pass. This effect is of particular concern in the design of modern high average current energy recovery accelerators utilizing superconducting RF technology. Experimental characterization and observations of the instability at the Jefferson Laboratory 10 kW Free Electron Laser (FEL) are presented. Measurements of the threshold current for the instability are made under a variety of beam conditions and compared to the predictions of several BBU simulation codes. This represents the first time in which the codes have been experimentally benchmarked. With BBU posing a threat to high current beam operation in the FEL Driver, several suppression schemes were developed.

Christopher Tennant; David Douglas; Kevin Jordan; Nikolitsa Merminga; Eduard Pozdeyev; Haipeng Wang; Todd I. Smith; Stefan Simrock; Ivan Bazarov; Georg Hoffstaetter

2006-03-24

3

Laboratory Experimentation in Economics  

Directory of Open Access Journals (Sweden)

Full Text Available Experimental economics is the application of experimental methods to study economic questions. Data collected in experiments are used to estimate effect size, test the validity of economic theories, and illuminate market mechanisms. Economic experiments usually use cash to motivate subjects, in order to mimic real-world incentives. Experiments are used to help understand how and why markets and other exchange systems function as they do. A fundamental aspect of the subject is design of experiments. Experiments may be conducted in the field or in laboratory settings, whether of individual or group behavior. Variants of the subject outside such formal confines include natural and quasi-natural experiments.

Dimitrios Koumparoulis

2013-02-01

4

Experimental investigation of the formation and propagation of plasma jets created by a power laser: application to laboratory astrophysics  

International Nuclear Information System (INIS)

Plasma jets are often observed in the polar regions of Young Stellar Objects (YSO). For a better understanding of the whole processes at the origin of their formation and evolution, this research thesis aims at demonstrating the feasibility of a plasma jet generation by a power laser, and at investigating its characteristics. After a detailed description of Young Stellar Objects jets and an overview of theoretical models, the author describes some experiments performed with gas guns, pulsed machines and power lasers. He describes means of generation of a jet by laser interaction via strong shock propagation. He reports experimental work, describing the target, laser operating conditions and the determination of jet parameters: speed, temperature, density. Then, he introduces results obtained for plasma jet propagation in vacuum, describes their evolution with respect to initial conditions (target type, laser operating conditions), and identifies optimal conditions for generating a jet similar to that in astrophysical conditions. He considers their propagation in ambient medium like for YSO jets in interstellar medium. Two distinct cases are investigated: collision of two successive shocks in a gaseous medium, and propagation of a plasma jet in a gas jet

2008-01-01

5

Theoretical investigations of experimental gravitation  

International Nuclear Information System (INIS)

This thesis has two basic themes: the investigation of new experiments which can be used to test relativistic gravity, and the investigation of new technologies and new experimental techniques which can be applied to make gravitational wave astronomy a reality. Advancing technology will soon make possible a new class of gravitation experiments: pure laboratory experiments with laboratory sources of non-Newtonian gravity and laboratory detectors. The key advance in technology is the development of resonant sensing systems with very low levels of dissipation. Chapter 1 considers three such systems (torque balances, dielectric monocrystals, and superconducting microwave resonators), and it proposes eight laboratory experiments which use these systems as detectors. The coupled electro-mechanical system consisting of a microwave cavity and its walls can serve as a gravitational radiation detector. A gravitational wave interacts with the walls, and the resulting motion induces transitions from a highly excited cavity mode to a nearly unexcited mode. Chapter 2 describes briefly a formalism for analyzing such a detector, and it proposes a particular design. The monitoring of a quantum mechanical harmonic oscillator on which a classical force acts is important in a variety of high-precision experiments, such as the attempt to detect gravitational radiation. Chapter 3 reviews the standard techniques for monitoring the oscillator; and it introduces a new technique which, in principle, can determine the details of the force with arbitrary accuracy, despite the quantum properties of the oscillator

1979-01-01

6

Lindhurst Laboratory of Experimental Geophysics  

Science.gov (United States)

This Web site illustrates the California Institute of Technology's Lindhurst Laboratory of Experimental Geophysics research in dynamic compressions of minerals. The site describes how seismologists became interested in the physical properties of minerals within the high pressure and high temperature environment of the Earth's interior. With a series of images and figures of the shock wave equipment and the schematic of the VISAR setup, students and educators can learn about their current research in shock loading and impact. The site also provides links to the staff's research where scientists can find out about studies in thermodynamical models of impact-induced vaporization, laser ablation-ionization, Time-of-Flight Mass Spectrometry (TOFMS), and more.

7

Experimental Investigations of the Existence of a Local-Time Effect on the Laboratory Scale and the Heterogeneity of Space-Time  

Directory of Open Access Journals (Sweden)

Full Text Available The main subject of this work is an experimental investigation of the existence of a local-time effect on the laboratory scale, i.e. longitudinal distances between locations of measurements from one metre to tens of metres. A short review of our investigations of the existence of a local-time effect for longitudinal distances from 500 m to 15 km is also presented. Besides investigations of the minimal spatial scale for a local-time effect, the paper presents investigations of the effect in the time domain. In this relation the structure of intervals distribution in the neighbourhood of local-time peaks was studied and splitting of the peaks was revealed. Further investigations revealed second order splitting of local-time peaks. From this result it is concluded that space-time heterogeneity, which follows from the local-time effect, probably has fractal character. The results lead to the conclusion of sharp anisotropy of space-time.

Shnoll S.E.

2007-01-01

8

Experimental investigations on desiccant wheels  

International Nuclear Information System (INIS)

Experimental investigations on several commercially available and newly fabricated rotors are conducted in two different laboratories to evaluate performance trends. Experimental uncertainties are analysed and the parameters determining the rotor performance are investigated. It is found that the optimal rotation speed is lower for lithium chloride or compound rotors than for silica gel rotors. Higher regeneration air temperatures lead to higher dehumidification potentials at almost equal dehumidification efficiencies, but with increasing regeneration specific heat input and enthalpy changes of the process air. The influence of the regeneration air humidity was also notable and low relative humidities increase the dehumidification potential. Finally, the measurements show that rising water content in the ambient air causes the dehumidification capacity to rise, while the dehumidification efficiency is not much affected and both specific regeneration heat input and latent heat change of the process air decrease. For desiccant cooling applications in humid climates this is a positive trend. - Highlights: ? New experimental results on a range of desiccant wheels. ? High dehumidification capacities and low enthalpy changes for process air high water content. ? Higher regeneration temperature increases capacity, but lowers energy efficiency.

2012-09-01

9

Experimental investigation of horizontal shaft wind turbine  

International Nuclear Information System (INIS)

Presented are the results of experimental studies of wind engine with a horizontal axis. Investigations are carried out on the test stand in Laboratory of hydropower and hydraulic turbomachinery of the Technical University of Sofia. Shown are the performance characteristics of the wind engine for several patterns of work characterised by different values of the speed of the wind. A comparison was made with passport features. (authors)

2010-09-16

10

Investigation of the effects of fractured porous media on hydraulic tests—an experimental study at laboratory scale using single well methods  

Science.gov (United States)

In this paper, a study of detailed pneumatic tests at laboratory scale is presented. The study comprises two different test methods, which were conducted on an unsaturated fractured sandstone block of about 1 m 3 volume. First, a steady-state flow field with constant gas injection pressure and consequently constant gas flow rates was applied to the fractured sandstone block via a vertical borehole. The discharge of the injected gas was measured at the block surface. Second, a constant gas pressure was injected over the borehole and the transient pressure buildup was recorded at the block surface. It was the objective of the study to investigate the effects of the fractured porous system on pneumatic measurements and to provide an insight into processes occurring during flow and pressure buildup in fractured porous media. This is an essential prerequisite for a reliable validation of different modeling approaches, and it can further assist to improve techniques for the determination of the heterogeneity of hydraulic parameters in fractured porous media. The analysis of the distribution of the flow field and the temporal and spatial evolution of pressure buildup during the hydraulic tests shows that the direction and contribution of the flow field is highly depending on the spatial distribution and the characteristics of the fracture network as well as on the position of the observation points with respect to highly conductive structures. Finally, the introduced test methods are suitable tools for the characterization of the heterogeneous nature of fractured porous media and for the interpretation of the effects of the heterogeneous system on hydraulic tests.

Leven, C.; Sauter, M.; Teutsch, G.; Dietrich, P.

2004-09-01

11

Emissions from waste combustion. An application of statistical experimental design in a laboratory-scale boiler and an investigation from large-scale incineration plants  

Energy Technology Data Exchange (ETDEWEB)

The aim of this thesis is a study of the emissions from the combustion of household refuse. The experiments were both on a laboratory-scale boiler and on full-scale incineration plants. In the laboratory, an artificial household refuse with known composition was fed into a pilot boiler with a stationary grate. Combustion was under non-optimum conditions. Direct sampling with a Tenax adsorbent was used to measure a range of VOCs. Measurements were also made of incompletely burnt hydrocarbons, carbon monoxide, carbon dioxide, oxygen and flue gas temperature. Combustion and emission parameters were recorded continuously by a multi-point data logger. VOCs were analysed by gas chromatography and mass spectrometry (GC/MS). The full-scale tests were on seven Swedish incineration plants. The data were used to evaluate the emissions from large-scale incineration plants with various type of fuels and incinerators, and were also compared with the laboratory results. The response surface model developed from the laboratory experiments was also validated. This thesis also includes studies on the gasification of household refuse pellets, estimations of particulate and soot emissions, and a thermodynamic analysis of PAHs from combustion flue gas. For pellet gasification, experiments were performed on single, well characterised refuse pellets under carefully controlled conditions. The aim was to see if the effects of pellets were different from those of untreated household refuse. The results from both laboratory and full-scale tests showed that the main contributions to emissions from household refuse are plastics and moisture. 142 refs, 82 figs, 51 tabs

Zhang Xiaojing

1997-05-01

12

Laboratory investigation of tyre sliding grip coefficient  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper presents the results of a laboratory investigation on the variation of the tyre sliding grip coefficient depending on the tyre construction, the air pressure, the vertical load and the wheel camber. Eight different models of tyres are tested. A significant reduction of the tyre sliding grip coefficient on a hard ground was registered, when the tyre pressure is low and the wheel camber is bigger. The analysis of results and explanation of causes are done.

Ivanov, Rosen; Rusev, Rusi; Ilchev, Plamen

2006-01-01

13

Experimental investigations of ICRF effects  

International Nuclear Information System (INIS)

The goal of the Phaedrus program is to establish the relative efficiency of helicity and momentum current drive for rf near and below omegaci and compare to theory. This paper discusses major accomplishments in the rf program; extension of operating parameters; facility improvements; and additional experimental activities

1991-01-01

14

Experimental investigations of ICRF effects  

Energy Technology Data Exchange (ETDEWEB)

The goal of the Phaedrus program is to establish the relative efficiency of helicity and momentum current drive for rf near and below omega{sub ci} and compare to theory. This paper discusses major accomplishments in the rf program; extension of operating parameters; facility improvements; and additional experimental activities. (LSP)

1991-01-01

15

Experimental investigation of wave boundary layer  

DEFF Research Database (Denmark)

A review is presented of experimental investigation of wave boundary layer. The review is organized in six main sections. The first section describes the wave boundary layer in a real-life environment and its simulation in the laboratory in an oscillating water tunnel and in a water tank with an oscillating seabed. A brief account is given of measured quantities, measurement techniques (LDA, PIV, flow visualization) and limitations/constraints in the experimental investigation of the wave boundary layer in the laboratory. The second section concentrates on uniform oscillating boundary layers with a smooth bed. The boundary layer process is described over the entire range of the Reynolds number (Re from practically nil to Re = O(107)), from the laminar regime to the transitional regime and to the fully developed turbulent regime. The third section focuses on the effect of the boundary roughness. Results of recent research on wave boundary layers over a bed with large roughness (such as a/ks = O(1)) are also included in the review. The fourth section describes the effect of superimposed current on the wave boundary layer. The entire ¿spectrum¿, namely from the wave-dominated regime to the current-dominated regime, is covered. Processes such as turbulence reduction/re-laminarization, and increase/decrease in the bed shear stress are presented. The fifth section considers various effects on the wave boundary layer such as the non-uniformity (that due to change in the boundary roughness and that due to change in the flow geometry, i.e., the divergent/convergent environment); irregular waves, the angle of attack of waves; the effect of an externally generated field of turbulence; the suction and injection at the boundary (the ventilated boundary layers); and the vegetation. Also a brief account is given of the steady streaming (in a progressive wave and in a standing wave). The final section summarizes the results of recent research on coherent structures in wave boundary layers.

Sumer, B. Mutlu

2003-01-01

16

Experimental Investigations on Market Behavior  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Esta tesis consta de tres ensayos sobre las expectativas de inflación, la incertidumbre de la predicción, y la importancia de la incertidumbre en subastas secuenciales. Todos ellos utilizan un método experimental. El capítulo 1 estudia cómo los individuos predicen la inflación en la economía ficticia y analiza el efecto de las reglas de política monetaria en sus decisiones. Los resultados revelan la heterogeneidad en las reglas de predicción de la inflación y demuestran la importanc...

2012-01-01

17

Laboratory investigation of constitutive property scaling behavior  

International Nuclear Information System (INIS)

Because many constitutive rock properties must be measured at one scale but applied at another, scaling behavior is an issue facing many applied disciplines, including the petroleum industry. A research program has been established to investigate and a quantify scaling behavior through systematic physical experimentation, with the aim of developing and testing models that describe scaling behavior in a quantitative manner. Scaling of constitutive rock properties is investigated through physical experimentation involving the collection of gas-permeability data measured over a range of discrete scales. The approach is to systematically isolate those factors that influence property scaling and investigate their relative contributions to overall scaling behavior. Two blocks of rock, each exhibiting differing heterogeneity structure. have recently been examined. The two samples were found to yield different scaling behavior, as exhibited by changes in the distribution functions and semi-variograms. Simple models have been fit to the measured scaling behavior that are of similar functional form but of different magnitude

1994-09-25

18

Experimental Investigation of Microstructured Evaporators  

International Nuclear Information System (INIS)

Microfluidic devices have become more and more popular over the last decades. Cooling is a topic where microstructures offer significant advantages compared to conventional techniques due the much higher possible surface to volume ratios and short heat transfer lengths. By evaporating of a fluid in microchannels, compact, fast and powerful cooling devices become possible. Experimental results for different designs of microstructured evaporators are presented here. They have been obtained either using water as evaporating coolant or the refrigerant R134a (Tetrafluoroethane). A new microstructured evaporator design consisting of bended microchannels instead of straight channels for a better performance is shown and compared to previous results for the evaporation of R134a in straight microchannels.

2012-11-26

19

Rhodium Carbonyl Hydride Species. A Theoretical and Experimental Investigation.  

Science.gov (United States)

A theoretical investigation (ab initio) and experimental data have been combined in an attempt to characterize the rhodium carbonyl hydride species which has been shown previously in these laboratories and in those of Solymosi to be a long-lived surface s...

M. L. McKee C. H. Dai S. D. Worley

1987-01-01

20

Laboratory Investigations of Lava Flow Heat Transfer  

Science.gov (United States)

To investigate the effectiveness with which lava can heat substrates of different types, we conducted a suite of experiments in which molten basalt was poured onto solid or particulate materials, and the downward propagation of the heat pulse was measured. The motivation for this work lies in seeking to understand how lava flows on the Moon would have heated the underlying regolith, and thus to determine the depths at which solar wind particles implanted in the regolith would have been protected from the heat of the overlying flow. Extraction and analysis of ancient solar wind samples would provide a wealth of information on the evolution and fate of the Sun. Our experimental device consists of a box constructed from 1"-thick calcium silicate sheeting with interior dimensions of 20 x 20 x 25 cm. The substrate material (a particulate lunar regolith simulant or solid basalt) occupies the lower 15 cm of the box, which is embedded with an array of 8 thermocouples. Up to 6 kg of crushed basalt collected from the 2010 Kilauea lava flows is heated to supraliquidus temperatures and poured directly onto the substrate. The evolution of the temperature profile within the lava flow and substrate is recorded as the basalt cools, and the surface temperature distribution is recorded using a Forward Looking Infrared Radiometer (FLIR) video camera. We have been using the experimental data sets to validate a numerical model of substrate heating. If the physics is appropriately formulated, the model will accurately predict both surface and internal temperature distribution as a function of time. A key issue has been incorporation of valid temperature-dependent thermophysical properties, because particulate materials are not well characterized at elevated temperatures. Regolith thermal conductivity in particular exerts a strong control over the depth of penetration of the thermal wave, so its accurate description is essential for a robust model. Comparison of experimental vs. modeled temperature distributions has allowed for refinement of thermophysical properties. The numerical simulations closely approximate the temperature profile within the regolith simulant and confirm an elevated thermal conductivity that varies with temperature. Full validation of the model under a range of conditions will permit its application to the lunar environment to determine conditions favorable for the preservation of ancient solar wind deposits.

Fagents, S. A.; Rumpf, M. E.; Hamilton, C. W.

2011-12-01

 
 
 
 
21

The Experimental and Electronics Laboratories of the British Hovercraft Corporation.  

Science.gov (United States)

The facilities and kind of work undertaken by the Experimental and Electronics Laboratories of the British Hovercraft Corporation are described. In addition to hydrodynamic, aerodynamic and structural work, EEL also manufactures electronic instrumentation...

P. Mandel

1970-01-01

22

Preliminary Rock Mechanics Laboratory: Investigation Plan.  

Science.gov (United States)

This document presents the rationale for rock mechanics laboratory testing (including the supporting analysis and numerical modeling) planned for the site characterization of a nuclear waste repository in salt. This plan first identifies what information ...

K. P. Oschman R. G. Hummeldorf H. R. Hume M. Karakouzian J. E. Vakili

1987-01-01

23

Preliminary rock mechanics laboratory: Investigation plan  

Energy Technology Data Exchange (ETDEWEB)

This document presents the rationale for rock mechanics laboratory testing (including the supporting analysis and numerical modeling) planned for the site characterization of a nuclear waste repository in salt. This plan first identifies what information is required for regulatory and design purposes, and then presents the rationale for the testing that satisfies the required information needs. A preliminary estimate of the minimum sampling requirements for rock laboratory testing during site characterization is also presented. Periodic revision of this document is planned.

Oschman, K.P.; Hummeldorf, R.G.; Hume, H.R.; Karakouzian, M.; Vakili, J.E.

1987-01-01

24

Preliminary rock mechanics laboratory: Investigation plan  

International Nuclear Information System (INIS)

This document presents the rationale for rock mechanics laboratory testing (including the supporting analysis and numerical modeling) planned for the site characterization of a nuclear waste repository in salt. This plan first identifies what information is required for regulatory and design purposes, and then presents the rationale for the testing that satisfies the required information needs. A preliminary estimate of the minimum sampling requirements for rock laboratory testing during site characterization is also presented. Periodic revision of this document is planned

1987-01-01

25

The Laboratory-Investigative Approach to Science Instruction.  

Science.gov (United States)

Compares two grade 12 science classes, one receiving instruction using the Laboratory-Investigative Approach, and the other using the Lecture-Laboratory Approach, in terms of certain cognitive factors and associated attitudes. (GA)

Raghubir, Karran P.

1979-01-01

26

Experimental investigation of thermal barriers. Final report  

International Nuclear Information System (INIS)

During this contract period, we completed the following small scale laboratory experiments: (a) plasma confinement by picket fence cusp magnetic fields. (b) Electrostatic plugging of picket fence cusps. (c) Investigations of sheath phenomena including: characteristics of probe sheaths, secondary electrons in a plasma-wall sheath, and end wall characteristics in TMX. (d) Suppression of secondary electron emission by permanent magnet produced multidipole magnetic field. (e) Electron thermal insulation by double layers and multiple double layers. Many of these investigations have already had important consequences in the development of improvement for neutral beam sources

1984-01-01

27

Numerical and Experimental Investigation of Tidal Current Energy Extraction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Numerical and experimental investigations of tidal current energy extraction have been conducted in this study. A laboratory-scale water flume was simulated using commercial computational fluid dynamics (CFD) code FLUENT. In the numerical model, the tidal current turbine is represented with an actuator disk, which produces a pressure drop associated with energy loss. The free water surface is considered in the model using a volume of fluid method and is allowed to deform fre...

Sun, Xiaojing

2008-01-01

28

The European Network of Analytical and Experimental Laboratories for Geosciences  

Science.gov (United States)

Integrating Earth Sciences infrastructures in Europe is the mission of the European Plate Observing System (EPOS).The integration of European analytical, experimental, and analogue laboratories plays a key role in this context and is the task of the EPOS Working Group 6 (WG6). Despite the presence in Europe of high performance infrastructures dedicated to geosciences, there is still limited collaboration in sharing facilities and best practices. The EPOS WG6 aims to overcome this limitation by pushing towards national and trans-national coordination, efficient use of current laboratory infrastructures, and future aggregation of facilities not yet included. This will be attained through the creation of common access and interoperability policies to foster and simplify personnel mobility. The EPOS ambition is to orchestrate European laboratory infrastructures with diverse, complementary tasks and competences into a single, but geographically distributed, infrastructure for rock physics, palaeomagnetism, analytical and experimental petrology and volcanology, and tectonic modeling. The WG6 is presently organizing its thematic core services within the EPOS distributed research infrastructure with the goal of joining the other EPOS communities (geologists, seismologists, volcanologists, etc...) and stakeholders (engineers, risk managers and other geosciences investigators) to: 1) develop tools and services to enhance visitor programs that will mutually benefit visitors and hosts (transnational access); 2) improve support and training activities to make facilities equally accessible to students, young researchers, and experienced users (training and dissemination); 3) collaborate in sharing technological and scientific know-how (transfer of knowledge); 4) optimize interoperability of distributed instrumentation by standardizing data collection, archive, and quality control standards (data preservation and interoperability); 5) implement a unified e-Infrastructure for data analysis, numerical modelling, and joint development and standardization of numerical tools (e-science implementation); 6) collect and store data in a flexible inventory database accessible within and beyond the Earth Sciences community(open access and outreach); 7) connect to environmental and hazard protection agencies, stakeholders, and public to raise consciousness of geo-hazards and geo-resources (innovation for society). We will inform scientists and industrial stakeholders on the most recent WG6 achievements in EPOS and we will show how our community is proceeding to design the thematic core services.

Freda, Carmela; Funiciello, Francesca; Meredith, Phil; Sagnotti, Leonardo; Scarlato, Piergiorgio; Troll, Valentin R.; Willingshofer, Ernst

2013-04-01

29

Leptospirosis in Ceylon - Epidemiological and Laboratory Investigation.  

Science.gov (United States)

Investigations are being carried out to establish the vectors for leptospira in Ceylon. For this purpose domestic and wild animals are trapped alive and, (1) their blood is examined for evidence of leptospiral antibodies, (2) their kidney tissue is cultur...

K. Nityananda

1969-01-01

30

Experimental investigation of the temperature transducers reliability  

International Nuclear Information System (INIS)

The purpose of the paper is to investigate experimentally the reliability characteristics of chromel-alumel thermal converters (TC). Experimental facility enabling to conduct multifactor reliability tests was developed and constructed. Computer was used for experiment programming; experiment procedure was randomized. After completing the experiment and treating its results, the nonlinear regression equation was obtained; it describes the deviations of TC readings from the real temperature, depending on temperature, vibration frequency and the period of TC operation. Characteristics of parametric reliability of TC under investigation were obtained by probability methods. The obtained equation of relationship between the deviations of TC readings from the real temperature and prevailing factors enables to determine the degree of transducer operation capacity in 600-750 deg C temperature range and 10-50 Hz vibration frequency range

1983-01-01

31

Experimental investigation of NIRS spatial sensitivity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Near infrared spectroscopy (NIRS) is regarded as a potential medical diagnostic technique for investigation of hemodynamic changes. However, uncertainties pertaining to the origin of NIRS signals have hampered its clinical interpretation. The uncertainities in NIRS measurements especially in case of living tissues are due to lack of rigorous combined theoretical-experimental studies resulting in clear understanding of the origin of NIRS signals. For their reliable interpretation it is importa...

Patil, Amol V.; Safaie, Javad; Moghaddam, Hamid Abrishami; Wallois, Fabrice; Grebe, Reinhard

2011-01-01

32

Reputation or Reciprocity? An Experimental Investigation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent evidence highlights the importance of social norms in many economic relations. However, many of these relationships are long-term and provide repeated game incentives for performance. We experimentally investigate interaction effects of reciprocity and repeated game incentives in two treatments (one-shot and repeated) of a gift-exchange game. In both treatments we observe reciprocity, which is strengthened in the repeated game. A detailed analysis shows that in the repeated game some s...

2001-01-01

33

Failure investigations in the nuclear materials laboratory  

International Nuclear Information System (INIS)

A report is given of damage to hydrostatic floating seals (with a single-stage pressure drop of 155 bar) from pressurized water reactors. The seals were manufactured from the steel X 22 CrNi 17 and plasmacoated with a layer of Cr_2O_3. The types of damage occurring (green discoloration and hump formation) are discussed in terms of their mechanistic causes. A further investigation involved metallographic examination with optical and scanning electron microscopes of seven specimens from thin-walled piping made of the finegrained, structural steel 17 MnMoV 6,4 in which cracking had occurred in weld regions, in particular, crack growth and the form of cracking at the weld root were investigated. (orig.)

1982-01-01

34

Mars Science Laboratory Mission and Science Investigation  

Science.gov (United States)

Scheduled to land in August of 2012, the Mars Science Laboratory (MSL) Mission was initiated to explore the habitability of Mars. This includes both modern environments as well as ancient environments recorded by the stratigraphic rock record preserved at the Gale crater landing site. The Curiosity rover has a designed lifetime of at least one Mars year (˜23 months), and drive capability of at least 20 km. Curiosity's science payload was specifically assembled to assess habitability and includes a gas chromatograph-mass spectrometer and gas analyzer that will search for organic carbon in rocks, regolith fines, and the atmosphere (SAM instrument); an x-ray diffractometer that will determine mineralogical diversity (CheMin instrument); focusable cameras that can image landscapes and rock/regolith textures in natural color (MAHLI, MARDI, and Mastcam instruments); an alpha-particle x-ray spectrometer for in situ determination of rock and soil chemistry (APXS instrument); a laser-induced breakdown spectrometer to remotely sense the chemical composition of rocks and minerals (ChemCam instrument); an active neutron spectrometer designed to search for water in rocks/regolith (DAN instrument); a weather station to measure modern-day environmental variables (REMS instrument); and a sensor designed for continuous monitoring of background solar and cosmic radiation (RAD instrument). The various payload elements will work together to detect and study potential sampling targets with remote and in situ measurements; to acquire samples of rock, soil, and atmosphere and analyze them in onboard analytical instruments; and to observe the environment around the rover. The 155-km diameter Gale crater was chosen as Curiosity's field site based on several attributes: an interior mountain of ancient flat-lying strata extending almost 5 km above the elevation of the landing site; the lower few hundred meters of the mountain show a progression with relative age from clay-bearing to sulfate-bearing strata, separated by an unconformity from overlying likely anhydrous strata; the landing ellipse is characterized by a mixture of alluvial fan and high thermal inertia/high albedo stratified deposits; and a number of stratigraphically/geomorphically distinct fluvial features. Samples of the crater wall and rim rock, and more recent to currently active surface materials also may be studied. Gale has a well-defined regional context and strong evidence for a progression through multiple potentially habitable environments. These environments are represented by a stratigraphic record of extraordinary extent, and insure preservation of a rich record of the environmental history of early Mars. The interior mountain of Gale Crater has been informally designated at Mount Sharp, in honor of the pioneering planetary scientist Robert Sharp. The major subsystems of the MSL Project consist of a single rover (with science payload), a Multi-Mission Radioisotope Thermoelectric Generator, an Earth-Mars cruise stage, an entry, descent, and landing system, a launch vehicle, and the mission operations and ground data systems. The primary communication path for downlink is relay through the Mars Reconnaissance Orbiter. The primary path for uplink to the rover is Direct-from-Earth. The secondary paths for downlink are Direct-to-Earth and relay through the Mars Odyssey orbiter. Curiosity is a scaled version of the 6-wheel drive, 4-wheel steering, rocker bogie system from the Mars Exploration Rovers (MER) Spirit and Opportunity and the Mars Pathfinder Sojourner. Like Spirit and Opportunity, Curiosity offers three primary modes of navigation: blind-drive, visual odometry, and visual odometry with hazard avoidance. Creation of terrain maps based on HiRISE (High Resolution Imaging Science Experiment) and other remote sensing data were used to conduct simulated driving with Curiosity in these various modes, and allowed selection of the Gale crater landing site which requires climbing the base of a mountain to achieve its primary science goals. The Sample Acquisition, Processing, a

Grotzinger, John P.; Crisp, Joy; Vasavada, Ashwin R.; Anderson, Robert C.; Baker, Charles J.; Barry, Robert; Blake, David F.; Conrad, Pamela; Edgett, Kenneth S.; Ferdowski, Bobak; Gellert, Ralf; Gilbert, John B.; Golombek, Matt; Gómez-Elvira, Javier; Hassler, Donald M.; Jandura, Louise; Litvak, Maxim; Mahaffy, Paul; Maki, Justin; Meyer, Michael; Malin, Michael C.; Mitrofanov, Igor; Simmonds, John J.; Vaniman, David; Welch, Richard V.; Wiens, Roger C.

2012-09-01

35

Downward two-phase flow experimental investigation  

International Nuclear Information System (INIS)

The results of an experimental investigation concerning the determination of some characteristics of two-component (air-water), two-phase mixtures in vertical downward flow are presented in this article. The experiments were carried out on two pipes, 44 and 90 mm in diameter. Measurements were particularly concerned with void fraction, obtained by the manometric method, in bubble flow regime and for the above mentioned configurations. Firstly, the results were compared with those obtained by other researchers under analogous conditions. Then, the differences in void fraction values from those calculated by means of some well-known correlations for pressure drop by friction were estimated. Experimental data were also dealt with by means of other usual significant correlations for characteristic velocities of the phases, void fraction, slip ratio, in upward flow. Specifically, the models of Wallis, Zuber and Findlay, and Sokolov were considered, and a satisfactory agreement was found

1976-01-01

36

Experimental investigation of the H- shape resonance  

International Nuclear Information System (INIS)

Calculating scattering cross sections for the system electron-hydrogen atom Macek and Burke find an unusually narrow shape resonance at 10.222 eV, just above the n=2 state of hydrogen. An experimental confirmation of this resonance is very desirable, but it seems to be difficult to observe it in scattering experiments. However, the electronic transition of this 1s2p state into the (1s)2 ground state of the H- ion should result in a spectral line at 1129.5 A with a width of 1.5 A, and according to oscillator strength calculations by Macek this line should be observable in a thermal hydrogen plasma. The present paper reports on the experimental investigation of a hydrogen arc plasma in the pertinent spectral range. (Auth.)

1975-08-18

37

Intergranular attack of alloy 600: laboratory investigations  

International Nuclear Information System (INIS)

In some steam generators, intergranular attack (IGA) has occurred on Alloy 600 tubes in the tube-tubesheet crevice region. In order to evaluate the physico-chemical parameters which influence this type of corrosion, electrochemical tests and pressurized capsule tests were implemented on Alloy 600. Electrochemical tests consisted of polarizing Alloy 600 C-rings at various potential values during 120 hours in 10% caustic solutions eventually additioned with carbonate, sulfate, phosphate or silicate. In capsule tests, concentration of the sodium hydroxide was also investigated. In these cases, redox potential was changed by addition of various metallic oxides. Test durations were up to 2600 hours at 320 and 350 deg C. IGA is observed in caustic media and is a stress assisted phenomenon; on mill annealed Alloy 600 it occurs in a potential range around the reversible hydrogen potential. If the potential is increased by few tens of mV, only SCC is observed. Intergranular corrosion is often more important with addition of carbonate or sulfate but is not strongly affected by the caustic concentration; silicate has an inhibiting effect. The corrosion depth along the grain boundaries increases with test temperature. After thermal treatment at 700 deg C, with or without chromium depletion, Alloy 600 is more resistant to IGA but not immune. (author)

1983-01-01

38

Experimental Emulsified Diesel and Benzen Investigation  

Directory of Open Access Journals (Sweden)

Full Text Available This study presents an experimental investigation of emulsified fuels as an operating material for vehicle engines. Water in fuel blends is still relatively unknown and unaccepted by the majority of people. Introducing water into the combustion chamber has been around for more than one time, through water injection systems and emulsification of water into fuel. Adding water to fules will reduce bad emissions of the vehicles. It is found that brake power, engine power and also the engine torque have been improved with the emulsified fuels for both diesel and benzen till 25% water percentage addition.

Suleiman Abu-Ein

2010-05-01

39

Experimental investigation of pneumatic soil vapor extraction  

Science.gov (United States)

Soil Vapor Extraction (SVE) is a common remediation technique for removing volatile organic compounds from unsaturated contaminated soils. Soil heterogeneities can however cause serious limitations to the applicability of SVE due to air bypassing low permeable areas of the soil, leading to diffusion limitation of the remediation. To enhance removal from areas subject to diffusion limitation a new remediation technique, pneumatic soil vapor extraction, is proposed. In contrast to traditional SVE, in which soil vapor is extracted continuously by a vacuum pump, pneumatic SVE is based on enforcing a sequence of large pressure drops on the system to enhance the recovery from the low-permeable areas. The pneumatic SVE technique was investigated in the laboratory using TCE as a model contaminant. 2D-laboratory tank experiments were performed on homogeneous and heterogeneous sand packs. The heterogeneous packs consisted of a fine sand lens surrounded by a coarser sand matrix. As expected when using traditional SVE, the removal of TCE from the low permeable lens was extremely slow and subject to diffusion limitation. In contrast when pneumatic venting was used removal rates increased by up to 77%. The enhanced removal was hypothesized to be attributed to mixing of the contaminated air inside the lens and generation of net advective transport out of the lens due to air expansion.

Høier, C. K.; Sonnenborg, T. O.; Jensen, K. H.; Kortegaard, C.; Nasser, M. M.

2007-01-01

40

Experimental Investigation of Shock Wave Surfing  

CERN Multimedia

Shock wave surfing is investigated experimentally in GALCIT's Mach 4.0 Ludwieg Tube. Shock wave surfing occurs when a secondary free-body follows the bow shock formed by a primary free-body; an example of shock wave surfing occurs during meteorite breakup. The free-bodies in the current investigation are nylon spheres. During each run in the Ludwieg tube a high speed camera is used to capture a series of schlieren images; edge tracking software is used to measure the position of each sphere. Velocity and acceleration are had from processing the position data. The radius ratio and initial orientation of the two spheres are varied in the test matrix. The variation of sphere radius ratio and initial angle between the centers of gravity are shown to have a significant effect on the dynamics of the system.

Parziale, N J; Hornung, H G; Shepherd, J E

2010-01-01

 
 
 
 
41

Experimental Investigation of Shock Wave Surfing  

Science.gov (United States)

Shock wave surfing is investigated experimentally in GALCIT's Mach 4.0 Ludwieg Tube. Shock wave surfing occurs when a secondary free-body follows the bow shock formed by a primary free-body; an example of shock wave surfing occurs during meteorite breakup. The free-bodies in the current investigation are nylon spheres. During each run in the Ludwieg tube a high speed camera is used to capture a series of schlieren images; edge tracking software is used to measure the position of each sphere. Velocity and acceleration are had from processing the position data. The radius ratio and initial orientation of the two spheres are varied in the test matrix. The variation of sphere radius ratio and initial angle between the centers of gravity are shown to have a significant effect on the dynamics of the system.

Parziale, N. J.; Hornung, H. G.; Shepherd, J. E.; Laurence, S. J.

2010-11-01

42

Experimental investigation of hydrogen cryogenic distillation  

International Nuclear Information System (INIS)

Research conducted in the last fifty years has shown that one of the most efficient techniques of tritium removing from the heavy water used as moderator and coolant in CANDU reactors (as those operated at Cernavoda NPP in Romania) is the hydrogen cryogenic distillation. Designing and implementing the concept of cryogenic distillation columns require experiments to be conducted as well as computer simulations. Particularly, computer simulations are of great importance in designing and evaluating the performances of a column or a series of columns. Experimental data obtained from laboratory work will be used as input for computer simulations run at larger scale (within the Pilot Plant for tritium and deuterium separations) in order to increase the confidence in the simulated results. The studies carried out so far were focused on the following: - Quantitative analyses of important parameters such as the number of theoretical plates, inlet areas, reflux flow, flow-rates extraction, working pressure, etc; - Column in-series connecting to fulfil the separation requirements. Bench-scale experiments were carried out to assess the performances of contact elements with continuous packing prepared in our institute. (authors)

2007-01-01

43

Experimental investigations of MFCI in Russia  

International Nuclear Information System (INIS)

This report contains a review of the experimental investigations of MFCI which are carried out as applied to the safety problems of LMFBR, mainly in IPPE. Until the present time these investigations have been performed in out of pile conditions, using different substances for molten fuel simulation. A brief description of the experimental installations and results obtained in the course of experimental program realization is given. In particular the results are presented on the study of MFCI phenomenology with regards to the influence on the interaction energy release of such factors as: type of molten fuel-coolant contact, temperature conditions, ratio of interacted masses, scale factor. Simulation experiments have been effectuated using the following pairs of interaction media: low-melting metals (Lead, Tin, Bismuth, Aluminium)/water; molten Titan and Stainless steel/water; molten Titan and Stainless steel/sodium, eutectic alloy potassium-sodium; alumina/sodium; thermite mixture (Zr + Fe_2O_3)/water, sodium. The experiments were carried out mainly with the melts masses below 1 kg, except for some series of the experiments on molten Lead-water interaction, where the melt masses as big as 40 kg were used. Initial temperatures of low-melting metals have not exceeded 800 deg. C, while for the Stainless steel, Titan melts and alumina they were equal to 2200 deg. and 2500 deg. C respectively. The temperature of the melt, obtained by combustion of the thermite mixture Zr + Fe_2O_3, was about 3000 deg. C. The first part of the MFCI investigation program has been completed for the present time. A set of the data on the dynamical characteristics of interactions (time delays, amplitudes and shape of interaction pressure pulses, duration of interaction stage) and conversion coefficients of melt thermal energy into mechanical one was obtained. Analysis of these results has shown an essentially milder interaction energetics in the case of alkali metals coolants as compared with water. Some review is given on the further program of the MFCI study. (author)

1994-06-06

44

Drainage Characteristics of Base Course Materials Laboratory Investigation.  

Science.gov (United States)

A laboratory investigation of the effects of high degrees of compaction on the drainage characteristics (i.e., permeability and effective porosity) of coarse-grained base course materials was made to provide data for improving subsurface drainage design c...

E. H. Nettles C. C. Calhoun

1967-01-01

45

Experimental investigation of Reykjavik city footbridge  

DEFF Research Database (Denmark)

This study describes experimental investigation of a 160 m long footbridge in Reykjavik. The bridge is a continuous post tensioned concrete beam spanning eight spans, the longest being 27.1 m. In plan, the structure has eye-catching spiral shape. Modal testing of the structure was conducted to identify its dynamic properties. As many as seven modes of vibration were identified in the low-frequency region up to 5 Hz. After this a series of controlled tests involving up to 38 test subjects were performed. These were designed to test vibration performance of the footbridge under various loading scenarios such as: single person either walking or jumping, group of people walking, jogging or jumping and stream of pedestrians. The severity of vibration responses of the bridge for different scenarios was then evaluated against vibration serviceability criteria defined in a guideline. It was found that the vibration performance of the bridge is quite satisfactory for wide range of loading conditions. ©2010 Society forExperimental Mechanics Inc.

Zivanovic, Stana; Ingólfsson, Einar Thór

2011-01-01

46

Experimental investigation of tube-shock-absorbers  

International Nuclear Information System (INIS)

The experimental simulation of the tube form shock-absorbers for dampering the shock experienced by the falling down cask with spent nuclear fuel at Ignalina NPP is carried out. The possibilities of reducing the maximum initial stresses in the shock-absorbers were found out. Dynamic tests of the shock-absorbers' models showed that the maximum initial compression stresses are close to the yield limit of the material. The average overall internal compression stresses depends on the location and position at the fall, and are 1.7-2.5 times lower than the initial maximum compression stress. It was shown that upright cuts and holes in the upper circumference of the tube were to be the effective means to reduce the maximum initial compression stress, and at the same time to improve the effectiveness of the shock-absorbers. Using in the work the cuts and perforations with different geometrical characteristics the maximum initial compression stress was reduced from 1.3 to 2.3 times. The experimental investigations proved the validity and correctness of the methodic of shock-absorbers calculations carried out in the work. (author)

1997-01-01

47

Experimental investigation of crater growth dynamics  

Science.gov (United States)

This work is a continuation of an ongoing program whose objective is to perform experiments and to develop scaling relationships for large-body impacts onto planetary surfaces. The centrifuge technique is used to provide experimental data for actual target materials of interest. With both power and gas guns mounted on the rotor arm, it is possible to match various dimensionless similarity parameters, which have been shown to govern the behavior of large-scale impacts. The development of the centrifuge technique has been poineered by the present investigators and is documented by numerous publications, the most recent of which are listed below. Understanding the dependence of crater size upon gravity has been shown to be key to the complete determination of the dynamic and kinematic behavior of crater formation as well as ejecta phenomena. Three unique time regimes in the formation of an impact crater have been identified.

Schmidt, R. M.; Housen, K. R.; Bjorkman, M. D.; Holsapple, K. A.

1985-01-01

48

Investigation of an Experimental Supersonic Axial-Flow Compressor  

Science.gov (United States)

An investigation is in progress at the Langley Laboratory of the NACA to explore the possibilities of axial-flow compressors operating with supersonic velocities relative to the blade rows. The first phase of this investigation, a study of supersonic diffusers, has been reported. The second phase, an analysis of supersonic compressors, has also been reported. Preliminary calculations have shown that very high pressure ratios across a stage, together with somewhat increased mass flows, are possible with compressors which decelerate air through the speed of sound in their rotor blading. These performance characteristics are desirable in compressors for aircraft jet propulsion units, gas turbines, or superchargers. The third phase, presented here, is a preliminary experimental investigation of a supersonic compressor designed to produce a high pressure ratio in a single stage.

Erwin, John R.; Wright, Linwood C.; Kantrowitz, Arthur

1947-01-01

49

Propane hydrate nucleation: Experimental investigation and correlation  

DEFF Research Database (Denmark)

In this work the nucleation kinetics of propane gas hydrate has been investigated experimentally using a stirred batch reactor. The experiments have been performed isothermally recording the pressure as a function of time. Experiments were conducted at different stirring rates, but in the same supersaturation region. The experiments showed that the gas dissolution rate rather than the induction time of propane hydrate is influenced by a change in agitation. This was especially valid at high stirring rates when the water surface was severely disturbed.Addition of polyvinylpyrrolidone (PVP) to the aqueous phase was found to reduce the gas dissolution rate slightly. However the induction times were prolonged quite substantially upon addition of PVP.The induction time data were correlated using a newly developed induction time model based on crystallization theory also capable of taking into account the presence of additives. In most cases reasonable agreement between the data and the model could be obtained. Theresults revealed that especially the effective surface energy between propane hydrate and water is likely to change when the stirring rate varies from very high to low. The prolongation of induction times according to the model is likely to be due to a change in the nuclei-substrate contact angle.

Jensen, Lars; Thomsen, Kaj

2008-01-01

50

Experimental Investigation of Transient Sublimator Performance  

Science.gov (United States)

Sublimators have been used as heat rejection devices for a variety of space applications including the Apollo Lunar Module and the Extravehicular Mobility Unit (EMU). Sublimators typically operate with steady-state feedwater utilization at or near 100%. However, sublimators are currently being considered for operations in a cyclical topping mode, which represents a new mode of operation for sublimators. Sublimators can be used as a supplemental heat rejection device during mission phases where the environmental temperature or heat rejection requirement changes rapidly. This scenario may occur during low lunar orbit, low earth orbit, or other planetary orbits. In these mission phases, the need for supplemental heat rejection will vary between zero and some fraction of the overall heat load. In particular, supplemental heat rejection is required for the portion of the orbit where the radiative sink temperature exceeds the system setpoint temperature. This paper will describe the effects of these transient starts and stops on the feedwater utilization during various feedwater timing scenarios. Experimental data from various scenarios is analyzed to investigate feedwater consumption efficiency under the cyclical conditions. Start up utilization tests were conducted to better understand the transient performance. This paper also provides recommendations for future sublimator design and transient operation.

Sheth, Rubik B.; Stephan, Ryan A.; Leimkuehler, Thomas O.

2012-01-01

51

Experimental investigations of image quality in xeroradiotomography  

International Nuclear Information System (INIS)

The xeroradiographic image quality of tomograms of structures within and outside the image plane is experimentally investigated using pictures of lead line screens and a dead skull. The lead line screens were inclined with respect to the image plane, so that the imaging quality of details of the image plane and blurring shadows could be quantitatively determined on the basis of the modulation transfer function. The xerotomogram was found to be richer in contrast, sharper, and easier to interpret than conventional screen tomograms. The contrast behaviour in xerotomograms is strongly dependent on the exposure. In a tomogram with optimum exposure, there should be maximum contrast between the structures within the image plane and minimum contrast between structures in the blurred area. The author has found that a compromise must be made between these two demands. For maximum difference between the two types of contrast in xeroradiotomography, images must be slightly underexposed. The blurring effect in xerotomograms is best demonstrated on isolated blurred pictures of slices of the skull phantom. A comparison with screen tomograms shows that the edge enhancement effect, which is a typical characteristic of xeroradiography, is also seen in the blurring shadows so that these get sharper and are less well distinguished from the structures within the image plane. (orig./MG)

1980-01-01

52

Experimental investigation of wingtip aerodynamic loading  

Science.gov (United States)

An experimental investigation was performed to obtain the aerodynamic loading of a series of wingtips. The wingtips varied in taper ratio (1.0, 0.6, and 0.3) and in sweep angle (0, 20, 30, 35, and 45 deg). The wingtips were tested separately (wingtip only configuration) and while mounted on a semi-span wing. The quarter-chord sweep angle of the wing was varied from 30 deg forward sweep, to unswept, to 30 deg. aft sweep. Wingtip loading was obtained from a six component strainguage balance mounted in the wingtip. The effect of wing sweep and wingtip taper and wingtip sweep on the wingtip lift curve slope, drag polar, and pitching moment behavior is discussed. The obtained wingtip data was used to define blade tip platforms, suitable for use in the Free-Tip Rotor configuration. The Free-Tip Rotor has blade tips, which are allowed to weathervane into the blade tip's relative wind. A passive control moment is applied to the blade tip's pitch axis so as to cause blade tip motion around a prescribed null point providing a finite blade tip lift.

Van Aken, Johannes M.

1990-01-01

53

Characterizing the Experimental Procedure in Science Laboratories: A Preliminary Step towards Students Experimental Design  

Science.gov (United States)

Many studies have stressed students' lack of understanding of experiments in laboratories. Some researchers suggest that if students design all or parts of entire experiment, as part of an inquiry-based approach, it would overcome certain difficulties. It requires that a procedure be written for experimental design. The aim of this paper is to…

Girault, Isabelle; d'Ham, Cedric; Ney, Muriel; Sanchez, Eric; Wajeman, Claire

2012-01-01

54

An experimental investigation of hyperpycnal flow  

Science.gov (United States)

The understanding of river-borne sediment dispersal in the coastal environment is an important problem in coastal/estuarine research. While it remains difficult to quantify how river discharges sediment into the coastal environment, it has been found that there are many qualitative similarities among rivers around the world. Amid these similarities is the formation of freshwater sediment-laden plumes, positively and negatively buoyant, that extend from river mouths into the ocean. Research has been conducted to help understand how sediment is deposited from these plumes for different idealized coastal settings. A series of laboratory experiments were performed to study sediment-laden freshwater plumes within a saltwater tank. Both hyperpycnal and hypopycnal plumes were created by pumping sediment-laden freshwater with a given sediment concentration into a saltwater tank with a constant salinity of 12.5 ppt. Salinity was measured prior to each experiment with the Mannix TDS503 Pocket TDS Meter. Kaolin clay with a primary particle size of D50 = 0.2 ?m was used. Freshwater and sediment were mixed in a 50 gallon barrel with fluorescent dye, which improves the visual distinction between the slurry and the ambient water. The saltwater tank is a 3 meter long, 0.15 meter wide, and 0.5 meter deep flume with an adjustable slope (four different slopes, 50, 30, 20, 10 degrees, were investigated) where the slurry enters. Four different sediment concentrations were used with each slope: 15 g/l, 20 g/l, 25 g/l, and 30 g/l, creating a total of sixteen trials for analysis. A Sony SR11 camcorder was used to capture video of the plumes as they move across the tank. Image analysis was performed using a Matlab code to measure parameters in order to describe the plumes. These include velocity, thickness, liftoff distance, and separation distance. Resultant plumes are found to depend on the initial sediment concentration of the slurry as well as the slope used at the entrance of the tank. . Observations were divided into three regimes: fully buoyant plumes (hypopycnal plume), submerged plumes (hyperpycnal plume) that separated from the slurry discharge, and fully submerged plumes that did not separate. Measured data is used to quantify the lift-off distance as a function of inlet condition and occurrence of divergent plume. For several high concentration trials, the occurrence of convective fingers is observed after plume lift-off. A hyperpycnal plume separtes from the discharge to move along the bottom of the tank, while a hypopycnal plume develops and moves along the surface.

Boland, T. M.; Hsu, T.

2010-12-01

55

Numerical and Experimental Investigation on Root Anchorage  

Science.gov (United States)

In more recent times, the roles played by vegetation in some specific geotechnical processes have been recognized. Vegetation may affect slope stability in many ways. The stability of slopes is governed by the load, which is the driving force that causes failure, and the resistance, which is the strength of the soil-root system. The weight of trees growing on a slope adds to the load but the roots of trees serve as a soil reinforcement and increase the resistance. In order to ensure that the weight of the trees on the slope help to enhance its stability it is required that they are planted down-slope of the neutral point. Maximum contribution is produced if the trees are located at the slope toe. Considering a typical slip circle, at this location the direction of shear force acting on the trees may be considered as close-to-vertical for the purpose of analysis. In this study, 3D numerical simulations of root anchorage have been performed to study the mechanism and the factors influencing the pull out capacity of tree roots. The investigation was performed using ABACUS finite element program. Field pull-out tests were also carried out on Melastoma malabathricum which been shown to be very suitable to be grown on slope, and the results are compared with numerical simulations. Parametric studies were also done to study the effects of factors such as root pattern, angle of inclination as well as soil properties. The results show that the 3D finite element analyses are able to approximately simulate the experimental tests. The results of the field tests, simulations and the parametric studies will be presented and discussed in more details in this paper.

Ali, F.; Osman, N.; Hashim, R.; Khalilnejad, A.

2012-04-01

56

Numerical and experimental investigation of downdraft gasification of wood chips  

International Nuclear Information System (INIS)

Highlights: ? We examined the efficiency of gasifying wood chips in a downdraft reactor using numerical and experimental methods. ? Feedstock density and heating value is important as it controls the flame stability. ? Improvements modeled gasifier include decreasing the heat losses, controlling the system leaks and enhancing the mixing. ? Max. temp. measured at the combustion zone as expected with a cold gas efficiency of 70% (CFD) vs. 89% (equilibrium model). - Abstract: Biomass is widely perceived as a potential renewable energy source. Thermo-chemical conversion technologies including gasification, co-firing, and pyrolysis are of primary interest due to their higher conversion efficiency and throughput when compared with the low temperature digestion and fermentation for lignocellulose and wood-based feedstock. In this paper, a small scale, air blown, downdraft gasification system is operated using wood to investigate its conversion efficiency. Wood chips of 0.5 cm thickness, 1–2 cm width, and 2–2.5 cm length constitute the feedstock to the downdraft gasifier that is assembled and instrumented at Masdar Institute’s Waste-to-Energy laboratory. The experimental investigation of the temperature field inside the gasifier is followed by high fidelity numerical simulation using CFD to model the Lagrangian particle coupled evolution. The numerical simulation is conducted on a high resolution mesh accounting for the solid and gaseous phases, k–? turbulence, and reacting CFD model. The temperature distribution and the evolution of species are computed and compared with the experimental results and with the ideal equilibrium, zero dimensional case.

2013-01-01

57

Investigating properties of white noise in the undergraduate laboratory  

International Nuclear Information System (INIS)

This paper describes a simple noise circuit for the undergraduate physics laboratory. Students use this circuit to study the properties of electrical noise on a personal computer. This is made possible by using a data acquisition system that allows the experimenters to obtain large amounts of data on the computer, suitable for subsequent mathematical computations. Various properties such as mean, noise power, noise power density and the probability distribution of noise voltages are also explored.

2009-09-01

58

Experimental investigation of bubble plume structure instability  

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: The hydrodynamic properties of a 3D bubble plume in a large water pool are investigated experimentally. Bubble plumes are present in various industrial processes, including chemical plants, stirred reactors, and nuclear power plants, e.g. in BWR suppression pools. In these applications, the main issue is to predict the currents induced by the bubbles in the liquid phase, and to determine the consequent mixing. Bubble plumes, especially large and unconfined ones, present strong 3D effects and a superposition of different characteristic length scales. Thus, they represent relevant test cases for assessment and verification of 3D models in thermal-hydraulic codes. Bubble plumes are often unsteady, with fluctuations in size and shape of the bubble swarm, and global movements of the plume. In this case, local time-averaged data are not sufficient to characterize the flow. Additional information regarding changes in plume shape and position is required. The effect of scale on the 3D flow structure and stability being complex, there was a need to conduct studies in a fairly large facility, closer to industrial applications. Air bubble plumes, up to 30 cm in base diameter and 2 m in height were extensively studied in a 2 m diameter water pool. Homogeneously sized bubbles were obtained using a particular injector. The main hydrodynamic parameters. i.e., gas and liquid velocities, void fraction, bubble shape and size, plume shape and position, were determined experimentally. Photographic and image processing techniques were used to characterize the bubble shape, and double-tip optical probes to measure bubble size and void fraction. Electromagnetic probes measured the recirculation velocity in the pool. Simultaneous two-phase flow particle image velocimetry (STPFPIV) in a vertical plane containing the vessel axis provided instantaneous velocity fields for both phases and therefore the relative velocity field. Video recording using two CCD cameras at a right angle provided instantaneous projections of the plume shape on two perpendicular planes. Image processing techniques were applied to determine the plume width and position and their fluctuations in time. Triggering the video recording process with the STPF-PIV system allowed to correlate the measured velocity fields with the plume position with respect to the vessel axis. Then, the velocity fields were ensemble - averaged for a given plume position. The results may significantly differ from the time - averaged velocity fields in a fixed plane, which were used in the past for code assessment. The present results should allow to better discriminate between effective plume spreading, due e.g. to turbulent dispersion, and superimposed, apparent spreading due to plume motion. Beyond this aspect, the achievement of local measurements of most flow parameters in fairly large bubble plumes is a unique tool for model validation. (authors)

Marco Simiano; Robert Zboray; Francois de Cachard [Thermal-Hydraulics Laboratory, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Djamel Lakehal; George Yadigaroglu [Institute of Energy Technology, Swiss Federal Institute of Technology, ETH-Zentrum/CLT, 8092 Zurich (Switzerland)

2005-07-01

59

Experimental investigation of bubble plume structure instability  

International Nuclear Information System (INIS)

Full text of publication follows: The hydrodynamic properties of a 3D bubble plume in a large water pool are investigated experimentally. Bubble plumes are present in various industrial processes, including chemical plants, stirred reactors, and nuclear power plants, e.g. in BWR suppression pools. In these applications, the main issue is to predict the currents induced by the bubbles in the liquid phase, and to determine the consequent mixing. Bubble plumes, especially large and unconfined ones, present strong 3D effects and a superposition of different characteristic length scales. Thus, they represent relevant test cases for assessment and verification of 3D models in thermal-hydraulic codes. Bubble plumes are often unsteady, with fluctuations in size and shape of the bubble swarm, and global movements of the plume. In this case, local time-averaged data are not sufficient to characterize the flow. Additional information regarding changes in plume shape and position is required. The effect of scale on the 3D flow structure and stability being complex, there was a need to conduct studies in a fairly large facility, closer to industrial applications. Air bubble plumes, up to 30 cm in base diameter and 2 m in height were extensively studied in a 2 m diameter water pool. Homogeneously sized bubbles were obtained using a particular injector. The main hydrodynamic parameters. i.e., gas and liquid velocities, void fraction, bubble shape and size, plume shape and position, were determined experimentally. Photographic and image processing techniques were used to characterize the bubble shape, and double-tip optical probes to measure bubble size and void fraction. Electromagnetic probes measured the recirculation velocity in the pool. Simultaneous two-phase flow particle image velocimetry (STPFPIV) in a vertical plane containing the vessel axis provided instantaneous velocity fields for both phases and therefore the relative velocity field. Video recording using two CCD cameras at a right angle provided instantaneous projections of the plume shape on two perpendicular planes. Image processing techniques were applied to determine the plume width and position and their fluctuations in time. Triggering the video recording process with the STPF-PIV system allowed to correlate the measured velocity fields with the plume position with respect to the vessel axis. Then, the velocity fields were ensemble - averaged for a given plume position. The results may significantly differ from the time - averaged velocity fields in a fixed plane, which were used in the past for code assessment. The present results should allow to better discriminate between effective plume spreading, due e.g. to turbulent dispersion, and superimposed, apparent spreading due to plume motion. Beyond this aspect, the achievement of local measurements of most flow parameters in fairly large bubble plumes is a unique tool for model validation. (authors)

2005-10-02

60

Experimental Investigations of Water Quality: The Bioassay.  

Science.gov (United States)

Describes a bioassay laboratory exercise designed to introduce students to both acute and chronic bioassay procedures. Reinforces ecological principles and provides opportunities for students to use knowledge learned in the classroom in a realistic and ecologically-relevant situation. Contains 11 references. (JRH)

Havel, John E.; And Others

1997-01-01

 
 
 
 
61

Application of geophysical methods to laboratory investigation of rock failure at sustained load conditions  

Energy Technology Data Exchange (ETDEWEB)

Experimental laboratory investigations, using several geophysical methods (ultrasonics, seismoacoustics, geoelectricity), were carried out on 3 rock types (pyrophyllite, greisen, bituminous coal). The deformation rate of test specimens during these experiments was 10/sup -6//s at first, then 10/sup -7//s to 10/sup -8//s. Individual measurements lasted 16-67 hours. The results of the measurements on pyrophyllite are discussed.

Dragan, V.

1982-09-01

62

Laboratory investigation of the loading rate effects in sand:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to improve the interpretation of the quasi-static (e.g. Statnamic) pile load tests, a research project has been started to investigate effects of the loading rate on the bearing capacity of a pile in sand. A series of laboratory tests has been carried out. The testing program consists of a series of triaxial tests for sand

Huy, N. Q.; Tol, A. F.; Ho?lscher, P.

2006-01-01

63

Laboratory Investigation of Soil Infiltration Through Pipe Joints.  

Science.gov (United States)

A laboratory investigation was made to develop a system of classifying soils according to the degree that soil infiltration through openings in joints or seams of pipe in storm-drain systems can be expected to occur. The soils tested were a poorly graded,...

E. H. Nettles J. R. Compton

1967-01-01

64

An Investigative, Cooperative Learning Approach to the General Microbiology Laboratory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Investigative- and cooperative-based learning strategies have been used effectively in a variety of classrooms to enhance student learning and engagement. In the General Microbiology laboratory for juniors and seniors at James Madison University, these strategies were combined to make a semester-long, investigative, cooperative learning experience involving culture and identification of microbial isolates that the students obtained from various environments. To assess whether this strategy wa...

2009-01-01

65

Experimental investigation on breaching of embankments:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Breaching of embankments has recently drawn more and more attention due to its importance in the development of early warning systems for embankment failures, in the evacuation plans of people at risk, in the design method of embankments based on a risk-approach, etc. The erosion process observed during embankment breaching tests in the laboratory and the analysis of the results are described in this paper. Five embankments, one constructed with pure sand, four with different sand-silt-clay m...

Zhu, Y.; Visser, P. J.; Vrijling, J. K.; Wang, G. Q.

2011-01-01

66

Experimental investigation of the plasma focus discharge  

International Nuclear Information System (INIS)

One reports the main experimental results obtained on low current level Focus discharges: 200 kA and 50 kA. Neutron and X-ray scaling laws from 50 kA up to 2500 kA have been established by taking into account all the results obtained at the Centre d'Etudes de Limeil. These scaling laws show the great interest of a 10 MA Plasma Focus device. To achieve this high current level, one present the experimental study of an explosive current generator driven plasma Focus

1978-01-01

67

Experimental analysis of nonlinear oscillations in the undergraduate physics laboratory  

Science.gov (United States)

In this paper, we present a simple experiment to introduce the nonlinear behaviour of oscillating systems in the undergraduate physics laboratory. The transverse oscillations of a spring allow reproduction of three totally different scenarios: linear oscillations, nonlinear oscillations reducible to linear for small displacements, and intrinsically nonlinear oscillations. The chosen approach consists of measuring the displacements using video photogrammetry and computing the velocities and the accelerations by means of a numerical differentiation algorithm. In this way, one can directly check the differential equation of the motion without having to integrate it, or perform an experimental study of the potential energy in each of the analysed scenarios. This experiment allows first year students to reflect on the consequences and the limits of the linearity assumption for small displacements that is so often made in technical studies.

Moreno, R.; Page, A.; Riera, J.; Hueso, J. L.

2014-01-01

68

RESULTS OF AUTOMOBILE BIOGAS ENGINE EXPERIMENTAL INVESTIGATION  

Directory of Open Access Journals (Sweden)

Full Text Available The results of experimental study of automotive ICE running using biogas with different volume content of CO2 are presented. Recommendations for choosing the values of air-fuel ratios and ignition timings for different operating modes of the automotive biogas engine depending on fuel chemical composition are given.

Abramchuk, F.

2013-06-01

69

Experimental investigation of the CO{sub 2} refrigeration cycle  

Energy Technology Data Exchange (ETDEWEB)

Worldwide efforts to reduce the environmentally harmful effects of chlorofluorocarbons revived the study of the CO{sub 2} refrigeration cycle. A laboratory prototype of the CO{sub 2} refrigeration cycle was built to experimentally investigate the cycle's performance potential. The performance of CO{sub 2} was compared with that of R-22 for water-chilling applications. Though the ideal cycle coefficient of performance (COP) of CO{sub 2} is only 50% to 60% that of R-22, the actual CO{sub 2} cycle performs similarly to the R-22 cycle. This large deviation between the ideal cycle and the actual cycle is due to the beneficial thermophysical properties of CO{sub 2}.

Hwang, Y.; Radermacher, R.

1999-07-01

70

Role of vegetation on erosion processes: experimental investigation  

Science.gov (United States)

Investigations on soil-system ecology are ever more oriented toward quantitative information based on the study of the linkages between physical processes and ecological response in rivers. As it is known, in presence of vegetation, the hydrodynamics characteristics of flow are principally determined by the mutual interrelation between the flow velocity field and the hydraulic behavior (completely submerged or emergent) of the vegetation elements. Much effort has been made toward identifying the theoretical law to interpret the vertical profile of flow longitudinal velocity in vegetated channels. Many theoretical and experimental studies in laboratory channels have been carried out and especially the case of submerged flexible vegetation has been examined (Termini, 2012). The effects of vegetation on flow velocity are significant and of crucial importance for stabilizing sediments and reducing erosion. Vegetation has a complex effect on walls roughness and the study of the hydrodynamic conditions of flow is difficult. Although most studies based on the "boundary layer" scheme so that the hydrodynamic conditions inside and above the vegetated layer are considered separately, some authors (Ghisalberti and Nepft, 2002; Carollo et al., 2008) claim that the "mixing layer" scheme is more appropriate to define the velocity profile both inside and outside the vegetated layer. Experimental program has been recently carried out in two laboratory flumes constructed at the laboratory of Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali - University of Palermo (Italy) with real and flexible vegetation on the bed. In this paper, attention is paid to the influence of vegetation on the erosion processes both on the bed and on the channel banks. The structure of the detailed flow velocity field is analyzed and compared with that obtained in absence of vegetation. Attention is then devoted to the analysis of soil erosion mechanism. Carollo F.G., Ferro V., Termini D. (2008). Flow velocity profile and turbulence characteristics in a vegetated straight flume. International Congress Riverflow 2008- Cesnme - Izmir (Turkey) 3-5 September Ghisalberti, M. & Nepf, H. M. 2002. Mixing layer and coherent structures in vegetated acquatic flows. Journal of Geophysical Reseach 107(2). Termini D. (2012). Experimental investigation on the role of vegetation on sediment transport mechanism: review of recent results - 9th ISE - International Symposium on Ecohydraulics - 2012, ISSN 0945-358X Vienna - CD proceedings-

Termini, Donatella

2014-05-01

71

Experimental facilities for plate-out investigations and future work  

International Nuclear Information System (INIS)

The safety of HTR under normal operation and accident conditions, the possibility of inspection, maintenance and repair or decontamination of single primary components as well as the safety of maintenance personnel are essentially determined by the transport- and deposition behaviour of the non gaseous fission - and activation products in the primary loop of the reactor. A comprehensive program has been started in 1969 in KFA in collaboration with various industrial firms and foreign institutions to investigate these problems. The program includes in-pile and out-pile experiments, simulating reactor conditions and also different laboratory experiments and extensive theoretical investigations. The aim of these efforts is to test experimentally the models and computercodes, which are used for prediction of transport and deposition behaviour of fission products for HTR's as well under normal as under accident conditions. Further more a verified dataset is to be established. In this paper a survey is given of the experimental facilities carried out by KFA or in cooperation with KFA

1981-05-01

72

Surface hydrological investigation of Horonobe Underground Research Laboratory project  

International Nuclear Information System (INIS)

Horonobe Underground Research Center of Japan Atomic Energy Agency has carried out investigated surface hydrogeological investigation in and around the Horonobe Underground Research Laboratory (URL) area as a part of Horonobe URL project. We continue meteorological observation, observation of river flux and water quality, soil moisture observation and groundwater level observation in order to understand recharge rate and groundwater flow in the shallow part, which are required for the setting of boundary and initial condition of the groundwater flow analysis. This report show current status and results of surface hydrogeological investigation in the Horonobe URL project. (author)

2007-01-01

73

Numerical and experimental investigations on cavitation erosion  

International Nuclear Information System (INIS)

A method is proposed to predict cavitation damage from cavitating flow simulations. For this purpose, a numerical process coupling cavitating flow simulations and erosion models was developed and applied to a two-dimensional (2D) hydrofoil tested at TUD (Darmstadt University of Technology, Germany) [1] and to a NACA 65012 tested at LMH-EPFL (Lausanne Polytechnic School) [2]. Cavitation erosion tests (pitting tests) were carried out and a 3D laser profilometry was used to analyze surfaces damaged by cavitation [3]. The method allows evaluating the pit characteristics, and mainly the volume damage rates. The paper describes the developed erosion model, the technique of cavitation damage measurement and presents some comparisons between experimental results and numerical damage predictions. The extent of cavitation erosion was correctly estimated in both hydrofoil geometries. The simulated qualitative influence of flow velocity, sigma value and gas content on cavitation damage agreed well with experimental observations.

2012-11-26

74

Numerical and experimental investigations on cavitation erosion  

Science.gov (United States)

A method is proposed to predict cavitation damage from cavitating flow simulations. For this purpose, a numerical process coupling cavitating flow simulations and erosion models was developed and applied to a two-dimensional (2D) hydrofoil tested at TUD (Darmstadt University of Technology, Germany) [1] and to a NACA 65012 tested at LMH-EPFL (Lausanne Polytechnic School) [2]. Cavitation erosion tests (pitting tests) were carried out and a 3D laser profilometry was used to analyze surfaces damaged by cavitation [3]. The method allows evaluating the pit characteristics, and mainly the volume damage rates. The paper describes the developed erosion model, the technique of cavitation damage measurement and presents some comparisons between experimental results and numerical damage predictions. The extent of cavitation erosion was correctly estimated in both hydrofoil geometries. The simulated qualitative influence of flow velocity, sigma value and gas content on cavitation damage agreed well with experimental observations.

Fortes Patella, R.; Archer, A.; Flageul, C.

2012-11-01

75

Experimental investigation of the iodine partition coefficient  

International Nuclear Information System (INIS)

Short-term values of the iodine partition coefficient (IPC) were evaluated experimentally by an air/water system over the following ranges of conditions: temperature = 25 to 70"0C, pH = 5 to 9, and iodine concentration = 10"-"9 to 10"-"2 kg iodine/m"3 H_2O. The experimental IPC values are relatively independent of temperature over the indicated range, but show a significant dependence on pH and iodine concentration. In basic solutions the short-term values are several orders of magnitude less than the true equilibrium values; in acid solutions, the differences are much less. These results are useful for predicting the disposition of iodine shortly (i.e., 1 to 10 h) after iodine has been released into an air/water environment

1985-01-01

76

Experimental investigation of radiation temperature in hohlraums  

International Nuclear Information System (INIS)

Radiation temperature in hohlraums is diagnosed by using two soft X-ray spectrometers and a multi-pinhole soft X-ray streak camera. Taking plasma closure effects of the diagnostic hole into consideration, the accuracy has been improved. 2D-images and processes of the hole closure and radiation temperature in the hohlraums vs time have been obtained. A preliminary model of the closure effect of diagnostic hole is proposed based on the experimental data

2001-04-01

77

Incentivised experimental investigations of the affect heuristic  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In recent years there has been increasing interest in using the related concepts of affect and evaluability to understand a wide range of decision behaviours. However, a common feature of studies to date is that they have adopted hypothetical payoff designs. Such an approach is open to criticisms of non-consequentiality. In this paper we address this criticism, presenting a series of incentivised, real payoff, experimental studies examining the roles of affect and, the related concept of eval...

Bateman, Ian J.; Slovic, Paul; Starmer, Chris

2006-01-01

78

Experimental Stage Separation Tool Development in NASA Langley's Aerothermodynamics Laboratory  

Science.gov (United States)

As part of the research effort at NASA in support of the stage separation and ascent aerothermodynamics research program, proximity testing of a generic bimese wing-body configuration was conducted in NASA Langley's Aerothermodynamics Laboratory in the 20-Inch Mach 6 Air Tunnel. The objective of this work is the development of experimental tools and testing methodologies to apply to hypersonic stage separation problems for future multi-stage launch vehicle systems. Aerodynamic force and moment proximity data were generated at a nominal Mach number of 6 over a small range of angles of attack. The generic bimese configuration was tested in a belly-to-belly and back-to-belly orientation at 86 relative proximity locations. Over 800 aerodynamic proximity data points were taken to serve as a database for code validation. Longitudinal aerodynamic data generated in this test program show very good agreement with viscous computational predictions. Thus a framework has been established to study separation problems in the hypersonic regime using coordinated experimental and computational tools.

Murphy, Kelly J.; Scallion, William I.

2005-01-01

79

Experimental investigation of cryogenic oscillating heat pipes.  

Science.gov (United States)

A novel cryogenic heat pipe, oscillating heat pipe (OHP), which consists of an 4 × 18.5 cm evaporator, a 6 × 18.5 cm condenser, and 10 cm length of adiabatic section, has been developed and experimental characterization conducted. Experimental results show that the maximum heat transport capability of the OHP reached 380W with average temperature difference of 49 °C between the evaporator and condenser when the cryogenic OHP was charged with liquid nitrogen at 48% (v/v) and operated in a horizontal direction. The thermal resistance decreased from 0.256 to 0.112 while the heat load increased from 22.5 to 321.8 W. When the OHP was operated at a steady state and an incremental heat load was added to it, the OHP operation changed from a steady state to an unsteady state until a new steady state was reached. This process can be divided into three regions: (I) unsteady state; (II) transient state; and (III) new steady state. In the steady state, the amplitude of temperature change in the evaporator is smaller than that of the condenser while the temperature response keeps the same frequency both in the evaporator and the condenser. The experimental results also showed that the amplitude of temperature difference between the evaporator and the condenser decreased when the heat load increased. PMID:20585410

Jiao, A J; Ma, H B; Critser, J K

2009-07-01

80

Geoengineering characterization of welded tuffs from laboratory and field investigations  

Energy Technology Data Exchange (ETDEWEB)

Welded tuff beneath Yucca Mountain adjacent to the Nevada Test Site (NTS) is being considered for development as a high-level radioactive waste repository by the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. Because access into Yucca Mountain has been limited to borehole explorations, early geoengineering materials characterizations have been derived from laboratory tests on cores from Yucca Mountain and from laboratory and field tests on welded tuffs located in G-Tunnel on the NTS. G-Tunnel contains welded tuffs that have similar properties and stress states to those at Yucca Mountain and has been the location for in situ rock mechanics testing. The purpose of this paper is to summarize the geoengineering material property data obtained to date and to compare appropriate laboratory and field data from G-Tunnel to findings from Yucca Mountain. Geomechanical and thermal data are provided and are augmented by limited geological and hydrological data. A comparison of results of laboratory measurements on tuffs from Yucca Mountain and G-Tunnel indicates good agreement between the bulk densities, saturations, moduli of elasticity, Poisson`s ratios, and P-wave velocities. The G-Tunnel tuff has slightly lower thermal conductivity, tensile strength, compressive strength and slightly higher matrix permeability than does the welded tuff near the proposed repository horizon at Yucca Mountain. From a laboratory-to-field scaling perspective, the modulus of deformation shows the most sensitivity to field conditions because of the presence of joints found in the field. 14 refs., 1 tab.

Zimmerman, R.M.; Nimick, F.B.; Board, M.P.

1984-12-31

 
 
 
 
81

Geoengineering characterization of welded tuffs from laboratory and field investigations  

International Nuclear Information System (INIS)

Welded tuff beneath Yucca Mountain adjacent to the Nevada Test Site (NTS) is being considered for development as a high-level radioactive waste repository by the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. Because access into Yucca Mountain has been limited to borehole explorations, early geoengineering materials characterizations have been derived from laboratory tests on cores from Yucca Mountain and from laboratory and field tests on welded tuffs located in G-Tunnel on the NTS. G-Tunnel contains welded tuffs that have similar properties and stress states to those at Yucca Mountain and has been the location for in situ rock mechanics testing. The purpose of this paper is to summarize the geoengineering material property data obtained to date and to compare appropriate laboratory and field data from G-Tunnel to findings from Yucca Mountain. Geomechanical and thermal data are provided and are augmented by limited geological and hydrological data. A comparison of results of laboratory measurements on tuffs from Yucca Mountain and G-Tunnel indicates good agreement between the bulk densities, saturations, moduli of elasticity, Poisson's ratios, and P-wave velocities. The G-Tunnel tuff has slightly lower thermal conductivity, tensile strength, compressive strength and slightly higher matrix permeability than does the welded tuff near the proposed repository horizon at Yucca Mountain. From a laboratory-to-field scaling perspective, the modulus of deformation shows the most sensitivity to field conditions because of the presence of the joints found in the field. 14 references, 1 table

1984-11-26

82

Geoengineering characterization of welded tuffs from laboratory and field investigations  

Energy Technology Data Exchange (ETDEWEB)

Welded tuff beneath Yucca Mountain adjacent to the Nevada Test Site (NTS) is being considered for development as a high-level radioactive waste repository by the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. Because access into Yucca Mountain has been limited to borehole explorations, early geoengineering materials characterizations have been derived from laboratory tests on cores from Yucca Mountain and from laboratory and field tests on welded tuffs located in G-Tunnel on the NTS. G-Tunnel contains welded tuffs that have similar properties and stress states to those at Yucca Mountain and has been the location for in situ rock mechanics testing. The purpose of this paper is to summarize the geoengineering material property data obtained to date and to compare appropriate laboratory and field data from G-Tunnel to findings from Yucca Mountain. Geomechanical and thermal data are provided and are augmented by limited geological and hydrological data. A comparison of results of laboratory measurements on tuffs from Yucca Mountain and G-Tunnel indicates good agreement between the bulk densities, saturations, moduli of elasticity, Poisson`s ratios, and P-wave velocities. The G-Tunnel tuff has slightly lower thermal conductivity, tensile strength, compressive strength and slightly higher matrix permeability than does the welded tuff near the proposed repository horizon at Yucca Mountain. From a laboratory-to-field scaling perspective, the modulus of deformation shows the most sensitivity to field conditions because of the presence of the joints found in the field. 14 references, 1 table.

Zimmerman, R.M.; Nimick, F.B.; Board, M.P.

1984-12-31

83

Investigation of Ag in the king scallop Pecten maximus using field and laboratory approaches  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The bioaccumulation, tissue and subcellular distributions of Ag were investigated in the king scallop Pecten maximus from the Bay of Seine fishery area (France) in laboratory and in field conditions. Experimental investigations with the radiotracer 110mAg showed that the scallop readily concentrated Ag when exposed via seawater and to a much lower extent when exposed via sediment. Retention of the metal incorporated via all tested contamination pathways was shown to be very strong, but the as...

2008-01-01

84

The experimental investigation of supersymmetry breaking  

International Nuclear Information System (INIS)

If Nature is supersymmetric at the weak interaction scale, what can we hope to learn from experiments on supersymmetric particles? The most mysterious aspect of phenomenological supersymmetry is the mechanism of spontaneous supersymmetry breaking. This mechanism ties the observable pattern of supersymmetric particle masses to aspects of the underlying unified theory at very small distance scales. In this article, I will discuss a systematic experimental program to determine the mechanism of supersymmetry breaking. Both pp and e+e- colliders of the next generation play an essential role

1995-08-21

85

Numerical and experimental investigations on catalytic recombiners  

International Nuclear Information System (INIS)

Numerous containments of European light water reactors (LWR) are equipped with passive auto-catalytic recombiners (PAR). These devices are designed for the removal of hydrogen generated during a severe accident in order to avoid serious damage caused by a detonation. PARs make use of the fact that hydrogen and oxygen react exothermally on catalytic surfaces generating steam and heat even below conventional ignition concentrations and temperatures. Activities at ISR aim at overcoming existing limitations of today's systems. These are e.g. limited conversion capacity or unintended ignition of the gaseous mixture due to overheating of the catalyst elements caused by strong reaction heat generation. Experiments at the REKO facilities are conducted in order to achieve a profound understanding of the processes inside a recombiner, such as reaction kinetics or heat and mass transfer. Innovative PAR designs which may overcome existing limitations can be developed based on the knowledge obtained from these experiments. For the analysis of the processes inside a PAR the numerical code REKO-DIREKT is being developed. The code calculates the local catalyst temperatures and the concentration regression along the catalyst plates. For the validation of the model numerous experiments have been performed with different types of coating and different plate arrangements. The first calculations fit well with the experimental results indicating a proper understanding of the fundamental processes. The paper describes the experiments as well as the numerical model and presents model calculations in comparison with experimental results. (authors)

2005-01-01

86

Improper ferroelectricity: A theoretical and experimental investigation  

Science.gov (United States)

A combined theoretical and experimental study has been made of the origins and properties of the improper ferroelectricity associated with structural modulations of non-zero wavelengths. Two classes of materials have been studied: rare earth molybdates (specifically, gadolinium molybdate: GMO), and potassium selenate and its isomorphs. In the former, the modulation is produced by a zone boundary phonon instability, and in the latter by the instability of a phonon of wave vector approximately two-thirds of the way to the zone-boundary. In the second case the initial result is a modulated structure whose repeat distance is not a rational multiple of the basic lattice repeat distance. This result is a modulated polarization which, when the basic modulation locks in to a rational multiple of the lattice spacing, becomes uniform, and improper ferroelectricity results. The origins of these effects have been elucidated by theoretical studies, initially semi-empirical, but subsequently from first-principles. These complemented the experimental work, which primarily used inelastic light scattering, uniaxial stress, and hydrostatic pressure, to probe the balance between the interionic forces through the effects on the phonons and dielectric properties.

Hardy, J. R.; Ullman, F. G.

1984-02-01

87

An experimental investigation of wind turbine wakes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present study the wake behind a scaled; Horizontal Axis Wind Turbine (HAWT) has been investigated. The experiments were performed at the Department of Energy and Process Engineering, at the Norwegian University of Science and Technology, NTNU. The turbine was installed in the wind tunnel at the department and measurements were performed at several distances behind the turbine to examine the development of the flow. A five-hole pitot probe was applied as measurement instrument. The inst...

2012-01-01

88

An experimental investigation on THF hydrate rystallization  

Energy Technology Data Exchange (ETDEWEB)

The metastable zone of THF hydrate crystallization was investigated. It was found that formation of THF hydrate was possible in between solution concentrations of 9 and 46 percent by weight. Induction time for nucleation was also determined. The results indicate that the lowest induction time for nucleation corresponded to hydrate crystallization from a solution with a THF concentration of 19 percent. This solution concentration matches with the stoichiometric percentage of THF in the crystalline hydrate. (Author)

Ganji, H.; Manteghian, M.; Sadaghiani Zadeh, K.; Torabi, F.

2005-07-01

89

Experimental investigations of active air bearings  

DEFF Research Database (Denmark)

Along with traditional oil lubrication, increasing demand for high-speed applications has renewed attention to gas bearings technology. Traditional aerostatic and aerodynamic gas lubrication has been widely used in a variety of applications, ranging from high-speed spindles to micro and meso-scale turbomachinery. The present paper deals with experimental rotordynamic testing of a flexible rotor supported by hybrid aerostaticaerodynamic gas journal bearing equipped with an electronic radial air injection system. From a rotordynamic point of view there are two phenomena that limit the widespread of traditional gas lubrication: 1) Low damping makes operation across critical speed dangerous, as even low level of unbalance can generate large vibration responses. This is especially problematic for gas bearing applications, which often operate in the supercritical region. Moreover, 2) An upper bound to supercritical operation is determined by the appearance of subsynchronous whirl instability. Due to the sudden increase in amplitude with respect to speed, this most often corresponds to the maximal attainable rotational speed of the system. Postponing the onset speed of instability poses therefore one of the greatest challenges in a high-speed gas bearing design. A great deal of research is devoted to attack such issues, where most propose passive designs such as compliant foil bearings, tilting pad and flexure pivot gas bearings. These solutions proved to be effective in improving static and dynamic properties of the bearings, however issues related to the manufacturing and accuracy of predictions has so far limited their applications. Another drawback is that passive bearings offer a low degree of flexibility, meaning that an accurate optimization is necessary for each application. The developed prototype active bearing offers several promising performance enhancements. Synchronous vibrations can be effectively addressed ensuring safe operation across the critical speeds; whirling instability is suppressed; interveningon the software, rather than the hardware can modify the response of the system. Implementing active lubrication adds however a considerable number of parameters and variables. The performance of a good control system lays most importantly on a good choice of control gains, which in general are different depending on the goal of the controller. Optimum tuning of the control loop is addressed experimentally, showing dependency on the supply pressure and, less prominently, the rotational velocity. Copyright © 2012 by ASME.

Santos, Ilmar

2012-01-01

90

Experimental investigation of offshore wave buoy performance  

DEFF Research Database (Denmark)

The important characteristic of sea waves is their high energy density, which is the highest among renewable energy sources. Having up to 2700 km. of shoreline, Iran has a great potential in construction of offshore wave buoys (hereafter called OWB). In this article a OWB model with the possibility of assembling different buoy configurations is introduced. The system is exposed to regular and irregular waves which are generated using wave maker in a 2D wave tank. Wave energy can be extracted from vertical oscillation of its floating buoy. The device is so designed as to operate in rotational (pitch) mode in addition to vertical (heave) motion. Some experiments are also conducted to demonstrate system performance. Experimental results in different conditions are presented and the effect of different buoy configurations on the system efficiency is studied. Numerical simulations that obtain the hydrodynamic coefficients and dynamic response (the Response Amplitude Operator or simply RAO) of each buoy in waves validate test results that the buoy with highest transfer function obtained in simulations has highest efficiency in power extraction. It is finally shown that the horizontal buoy is the most efficient configuration among other constructed buoys for extracting wave energy. The non-dimensional groups are studied and the output power of a full scale OWB is obtained based on similarity laws.

Chivaee, Hamid Sarlak; Seif, M.S.

2013-01-01

91

Rhodium carbonyl hydride species. A theoretical and experimental investigation  

Energy Technology Data Exchange (ETDEWEB)

A theoretical investigation (ab initio) and experimental data have been combined in an attempt to characterize the rhodium carbonyl hydride species which has been shown previously in these laboratories and in those of Solymosi to be a long-lived surface species for supported rhodium in the catalytic hydrogenation reactions for CO and CO/sub 2/. The calculations have predicted that a bent rhodium carbonyl hydride species is much more stable than a rhodium formyl species. They have also predicted that the Rh-H stretching frequency should be more than 300 cm/sup -1/ lower than the C-O stretching frequency for the rhodium carbonyl hydride species. This prediction is at odds with assigned Rh-H stretching frequencies for Rh organometallic complexes which place Rh-H and C-O stretching frequencies in the same region of the spectrum (2000-2200 cm/sup -1/). The experimental data are not conclusive on this point. The calculations do satisfactorily rationalize the enhanced dissociation of the C-O bond for the rhodium carbonyl hydride species caused by the presence of the hydride moiety.

McKee, M.L.; Dai, C.H.; Worley, S.D.

1988-03-10

92

Computational and experimental investigation of magnetized target fusion  

International Nuclear Information System (INIS)

In Magnetized Target Fusion (MTF), a preheated and magnetized target plasma is hydrodynamically compressed to fusion conditions. Because the magnetic field suppresses losses by electron thermal conduction in the fuel during the target implosion heating process, the compression may be over a much longer time scale than in traditional inertial confinement fusion (ICF). Bigger targets and much lower initial target densities than in ICF can be used, reducing radiative energy losses. Therefore, ''liner-on-plasma'' compressions, driven by relatively inexpensive electrical pulsed power, may be practical. Potential MTF target plasmas must meet minimum temperature, density, and magnetic field starting conditions, and must remain relatively free of high-Z radiation-cooling-enhancing contaminants. At Los Alamos National Laboratory, computational and experimental research is being pursued into MTF target plasmas, such as deuterium-fiber-initiated Z-pinches, and the Russian-originated MAGO plasma. In addition, liner-on-plasma compressions of such target plasmas to fusion conditions are being computationally modeled, and experimental investigation of such heavy liner implosions has begun. The status of the research will be presented

1996-06-16

93

Experimental Investigation of the Loss Coefficients in a Linear Cascade  

Science.gov (United States)

This paper reports results of experimental investigations on a linear cascade of axial compressor blades. Experiments were conducted in an open circuit subsonic wind tunnel of Aerodynamics Research Laboratory of the Iran University of Science and Technology. Different Reynolds numbers based on the blade chord length were examined, ranging from 80,000 to 500,000. Flow incidences were changed between ?8 to +8 degrees with 2 degrees intervals. Freestream turbulence intensity was changed between 1.25 to 4 percent corresponding to different mesh screens mounted upstream of the test model. All the above flow conditions provided to establish various flow regimes, in terms of fully laminar and transitional flows, around the blades. At a specified range of Reynolds numbers laminar separation bubble/bubbles occurred over the blade solid walls. Surface pressure distributions were measured utilizing a computerized data acquisition system. Fluctuating velocities were also measured at various positions around the separation bubble zone, using hot film anemometry. Surface oil flow visualization was carried out for some selected flow conditions. Experimental results were used to study boundary layer characteristics and to determine variations of loss coefficient with each of Reynolds number, flow incidence and turbulence intensity parameters for the test model.

Taghavi-Zenouz, Reza; Etemadi, Majed; Nabati, Mehdi

2014-06-01

94

???????????????? ??????????? ????? ? ???????????? ??????? Experimental investigation of wing with vortex generators ????????????????? ???????????? ????? ? ???????????? ??????  

Directory of Open Access Journals (Sweden)

Full Text Available  ???????? ?????????? ??????????? ? ?????????????? ????? ?????? ??????? ????? ? ????????????? ???????????? ??????? ? ??????? ??????? ?? ??????? ??????.  The idea of research of the organized vortex flow of a wing for the purpose of perfection of aerodynamic characteristics on the big angels of attack develops. The wing with vortex generators in the form of flows on a forward edge in low velocity wind tunnel was with that end in view investigated. It is shown, that the organized vortex flow of a wing with vortex generators on a forward edge practically does not change aerodynamic characteristics at small angels of attack and strongly influences on the big angels of attack, increasing the maximum elevating force and improving momentum characteristics at small change of drag. ??? ????????????????? ???????????????? ????????????? ?? ??????? ????? ????? ??????????? ???????????? ??????????????? ????????? ????????? ?????. ? ???? ????? ??????????? ????? ????????? ??????? ? ???????????? ?????? ? ???? ???????? ?? ???????? ?????? ? ??????????????? ???????????????? ?????. ?????????????? ???????? ????????? ????? ? ???????????? ?????? ?? ???????? ?????? ??????????? ?? ???????? ???????????????? ????????????? ??? ????? ????? ????? ? ?????? ?? ??????? ????? ?????, ?????????? ???????????? ????????? ???? ? ??????? ????????? ?????????????? ??? ????? ????????? ?????????????.

?.?. ???????

2010-01-01

95

Experimental investigation on carbon cluster structure  

International Nuclear Information System (INIS)

Photofragmentation of carbon cluster ions, produced by a pulsed classical laser ablation source, have been investigated by measuring the depletion of the isolated cluster ion packet as a function of the photodissociation laser fluence. The experiment has been performed for C+16 to C+36 irradiated at first by the second harmonic of a YAG laser, and in a second step by the third harmonic. The comparison between the depletion curves obtained from the two experiments leads us to speculate on the presence of at least two or three valence isomers displaying different stabilities. (orig.)

1993-07-02

96

Experimental Investigation of Orthoenstatite Single Crystal Rheology  

Science.gov (United States)

The plasticity of enstatite, upper mantle second most abundant mineral, is still poorly constrained, mostly because of its high-temperature (T) transformation into proto- and clino-enstatite at low pressure (P). Mackwell (1991, GRL, 18, 2027) reports a pioneer study of protoenstatite (Pbcn) single-crystal rheology, but the results do not directly apply to the orthorhombic (Pbca) mantle phase. Ohuchi et al. (2011, Contri. Mineral. Petrol , 161, 961) carried out deformation experiments at P=1.3 GPa on oriented orthoenstatite crystals, investigating the activity of [001](100) and [001](010) dislocation slip systems; they report the first rheological laws for orthoenstatite crystals. However, strain and stress were indirectly constrained in their experiments, which questioned whether steady state conditions of deformation were achieved. Also, data reported for [001](100) slip system were obtained after specimens had transformed by twinning into clinoenstatite. We report here new data from deformation experiments carried out at high T and P ranging from 3.5 to 6.2 GPa on natural Fe-bearing enstatite single crystals, using the Deformation-DIA apparatus (D-DIA) that equipped the X17B2 beamline of the NSLS (NY, USA). The applied stress and specimen strain rates were measured in situ by X-ray diffraction and imaging techniques (e.g., Raterron & Merkel, 2009, J. Sync. Rad., 16, 748; Raterron et al., 2013, Rev. Sci. Instr., 84, 043906). Three specimen orientations were tested: i) with the compression direction along [101]c crystallographic direction, which forms a 45° angle with both [100] and [001] axes, to investigate [001](100) slip-system activity; ii) along [011]c direction to investigate [001](010) system activity; iii) and along enstatite [125] axis, to activate both slip systems together. Crystals were deformed two by two, to compare slip system activities, or against enstatite aggregates or orientated olivine crystals of known rheology for comparison. Run products microstructures were investigated by transmission electron microscopy. Despite a significant hardening with P, enstatite [001](100) slip system is found to be the easiest system at mantle P and T. Furthermore, orthoenstatite crystals exhibit a higher sensitivity to stress than olivine crystals, i.e. a higher n exponent in classical power laws. At the low stress level prevailing in the Earth mantle, enstatite crystals are thus harder than olivine crystals.

fraysse, G.; Girard, J.; Holyoke, C. W.; Raterron, P.

2013-12-01

97

Valence fluctuation : experimental investigations using nuclear techniques  

International Nuclear Information System (INIS)

In the recent years a great deal of research has been carried out on the properties of rare earth systems with particular reference to SmS and certain solid solutions of SmS which exhibit mixed valence states. Three types of nuclear based investigations viz. X-ray induced electron emission spectroscopy, Moessbauer spectroscopy and positron annihilation spectroscopy are carried out on the valence fluctuations and some results obtained on the above mentioned rare earth systems are reported. The approach to connect the positron experiments with the physics of mixed valence systems is outlined. Some basic unresolved questions that arise in this regard are discussed. (A.K.)

1978-12-31

98

The experimental investigation of explosive opening switch  

International Nuclear Information System (INIS)

The explosive opening switch (EOS) used in explosive-driven magnetic-flux compression generator (EMCG) circuits was investigated. It is shown that (1) under certain conditions, the EOS voltage is hardly dependent on the size of the explosive and aluminium foil used in EOS; (2) with the explosive coated by an insulator pipe, the opening effect of EOS is better; (3) by use of EOS, a pulse with 5 kA current, 100 kV voltage and 250 ns risetime has been transferred into a resistance load. (author). 12 figs., 5 refs

1996-06-10

99

Experimental investigation of Hafnium Coulomb excitation  

International Nuclear Information System (INIS)

In this research work measurement and data analysis obtained from coulomb excitation of Hf are reported. Energetic proton beams with 2 to 2.8 MeV produced by Van de graph accelerator was applied. For this investigation 0.5 millimeter thick target of Hf with 2 centimeter square area has been applied. A HPGe detector with energy resolution of 230 eV at 5.9 keV photon energy have been used for photon measurement in the energy region of 3keV to 200keV emitted from coulomb excited nuclei or electrons levels of atom.

2012-08-27

100

Experimental Investigation of Thruster Cathode Physics  

Science.gov (United States)

Advanced ion propulsion technologies are being developed under the Nuclear Electric Xenon Ion System (NEXIS) program for use in outer planet exploration. A revolutionary approach to thruster cathode design is dictated by the very high lifetime and propellant throughput requirements for nuclear electric applications. In conventional dispenser hollow cathodes used in thrusters, processes leading to depletion, inadequate transport, or insufficient production of barium are among those limiting the lifetime. A reservoir hollow cathode is being developed to address each of these failure mechanisms, exploiting four design variables - matrix material, source material, geometry, and thermal design - to essentially eliminate established failure modes. The very long anticipated lifetime necessitates new life validation methods to augment or replace the conventional lifetest approach. One important tool for quickly evaluating design changes is the ability to measure barium density inside a hollow cathode and/or in the plume. The dependence of barium density on temperature and other factors is an extremely important indicator of cathode health, particularly if the ratio Ba:BaO is also obtained. Comparison of barium production for reservoir and conventional cathodes will enable an assessment of the efficacy of reservoir designs and the goal of reducing barium consumption at a given emission current level. This study describes benchmark measurements made on a conventional cathode previously operated in a 20-kW NEXIS laboratory engine. Data on cathode operation and life-limiting processes were obtained through direct, real-time monitoring of atoms and molecules. A high-resolution, tunable laser system was employed to detect absorption of the low-density barium atoms inside the cathode. The plume was monitored also, using a quadrupole mass spectrometer to monitor multiple species and measure ion charge ratios. Data obtained with retarding potential analyzers or other means are available for comparison. Detection of other important species associated with cathode function, including Ba+ and BaO, and oxides of tungsten such as WO3 or WO3-, is of great interest for reasons to be discussed.

Crofton, Mark

2004-11-01

 
 
 
 
101

Experimental Investigation and Fabrication of Pneumatic Punch  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the investigation, design and fabrication of blanking of thin sheet (0.1-2 mm of different sheet material. The blank diameter is considered as 10 mm. The study helped to evaluate the influence of tool clearance, burr formation, sheet thickness, punch/die size and blanking layout on the sheet deformation. The punch load variation with tool travel and stress distribution in the sheet has been obtained. The results indicate that a reduction in the tool clearance increases the blanking load and formation of burr increasing or decreasing at different pressure. The objective of this paper is to study the behaviour of punch and formation of burr.

A.K.GUPTA

2013-06-01

102

Experimental investigation of corrosion of structural materials  

International Nuclear Information System (INIS)

Conducted was the corrosion test of a recuperative metal-metal heat exchanger made of the stainless austenite 1Kh18M10T steel in a contact with the 1Kh2M steel, with a sodium coolant. A testing unit has operated at maximum temperatures of 600 and 700 deg C for about 3x104 hours. Oxygen content in liquid sodium has been maintained at about (2-5)x103 mas.%. A comparative testing has also been performed of some ferrite-perlite steels (1Kh2MBF, 1Kh2MB, 1KhMT and others) promising for being used in steam generators with a sodium coolant. An effect of chemical composition of austenite steels on dissolution and mass transfer in sodium was studied. The corrosion process of austenite and chromium steels has been investigated in a flow of the sodium-potassium alloy. The specific features of dissolving pure nickel in lithium have been considered as well as kinetics of ?-phase formation in austenite steels upon their corrosion in lithium

1977-01-01

103

Experimental investigation of spark discharge energy  

International Nuclear Information System (INIS)

Minimum ignition energy is one of the important characteristics for electrostatic sensitivity of explosives and determination of the spark discharge energy is necessary for decision making of explosion prevention. In this paper, the real spark discharge energy was determined by the integration of the measured voltage and discharge current in a needle-to-plate configuration. The influence of the charging voltage and polarity, the charging capacitance and the electrode gap on the spark discharge energy was investigated. It is shown that the energy deposited into the discharge system is always smaller than that stored in the charging capacitor, especially at lower voltages that the discharge shows one current pulse and the energy efficiency is less than 30%. The discharge becomes complete at higher voltages when the discharge shows double pulses and the energy efficiency is close to 100%. For given charging capacitance and voltage, the real discharge energy is determined by the discharge mode rather than the electrode gap or the voltage polarity.

2013-03-22

104

Experimental investigation of impeller influence on ventilator characteristics  

Energy Technology Data Exchange (ETDEWEB)

Influences of the radial impellers with different axial slots in the blade on the fluid flow behavior and therefore on the laboratory air model (ventilator) inner and outer characteristics are investigated. Special attention is focused on measurement techniques. (orig.)

Milanez, M.

2001-07-01

105

Seismic and geologic investigations of the Sandia Livermore Laboratory site  

International Nuclear Information System (INIS)

This report describes results of a seismic and geologic investigation in the vicinity of Sandia Laboratories property and Sandia's Tritium Building at Livermore, California. The investigation was done to define any seismically capable faults in the immediate area and to obtain necessary information to support estimates of future possible or probable ground motions. The work included a variety of geophysical measurements, trenching, seismologic studies, geologic examination, and evaluation of possible ground surface rupture at the site. Ground motions due to the maximum potential earthquake are estimated, and probability of exceedance for various levels of peak ground acceleration is calculated. Descriptions of the various calculations and investigative techniques used and the data obtained are presented. Information obtained from other sources relevant to subsurface geology and faulting is also given. Correlation and evaluation of the various lines of evidence and conclusions regarding the seismic hazard to the Tritium Building are included

1978-09-01

106

Experimental investigation of a flapping wing model  

Energy Technology Data Exchange (ETDEWEB)

The main objective of this research study was to investigate the aerodynamic forces of an avian flapping wing model system. The model size and the flow conditions were chosen to approximate the flight of a goose. Direct force measurements, using a three-component balance, and PIV flow field measurements parallel and perpendicular to the oncoming flow, were performed in a wind tunnel at Reynolds numbers between 28,000 and 141,000 (3-15 m/s), throughout a range of reduced frequencies between 0.04 and 0.20. The appropriateness of quasi-steady assumptions used to compare 2D, time-averaged particle image velocimetry (PIV) measurements in the wake with direct force measurements was evaluated. The vertical force coefficient for flapping wings was typically significantly higher than the maximum coefficient of the fixed wing, implying the influence of unsteady effects, such as delayed stall, even at low reduced frequencies. This puts the validity of the quasi-steady assumption into question. The (local) change in circulation over the wing beat cycle and the circulation distribution along the wingspan were obtained from the measurements in the tip and transverse vortex planes. Flow separation could be observed in the distribution of the circulation, and while the circulation derived from the wake measurements failed to agree exactly with the absolute value of the circulation, the change in circulation over the wing beat cycle was in excellent agreement for low and moderate reduced frequencies. The comparison between the PIV measurements in the two perpendicular planes and the direct force balance measurements, show that within certain limitations the wake visualization is a powerful tool to gain insight into force generation and the flow behavior on flapping wings over the wing beat cycle. (orig.)

Hubel, Tatjana Y.; Tropea, Cameron [Technische Universitaet Darmstadt, Fachgebiet Stroemungslehre und Aerodynamik, Darmstadt (Germany)

2009-05-15

107

Experimental study of driven magnetic relaxation in a laboratory plasma  

Science.gov (United States)

The Driven Relaxation Experiment (DRX) has been built at LANL to investigate the possibility of exploiting resonances in the nonlinear force-free equation [1] to optimize magnetic flux amplification and current multiplication for driven-relaxed spheromak-like plasmas, and to explore the application of these ideas to plasma astrophysics problems [2]. It is also our goal to see whether relaxed states with ?> ?1 can be formed and sustained. The experiment uses a planar magnetized coaxial gun (100--180 kA, 1--7 mWb) to generate driven- relaxed plasmas within a cylindrical flux-conserving boundary (0.9 m diameter). Unique features of DRX include high ?gun up to 3?1, and a continuously adjustable boundary elongation. The gun is powered by a 3- stage capacitor bank to form (10 kV, 500 ?F) and sustain (5 kV, 8 mF) the plasma for up to 500 ?s, corresponding to >10 Sweet-Parker times which allows the plasma to reach a quasi-steady-state. The primary diagnostic is a 48- channel 2D magnetic probe array that will map out a poloidal cross-section of the magnetic field configuration at one toroidal position. The full equilibrium magnetic field will be constructed using a combination of the experimental data and a nonlinear force-free equilibrium solver. We will present details of the experimental setup and the first experimental data. Supported by LANL LDRD. [1] Tang & Boozer, PRL 94, 225004 (2005); PRL 98, 175001 (2007) [2] Tang, ApJ 679, 1000 (2008).

Hsu, S. C.; Tang, X. Z.

2008-11-01

108

Experimental and numerical investigation of non-neutral complex plasmas  

Energy Technology Data Exchange (ETDEWEB)

A plasma of particles with the same sign of charge, can be easily confined under ultra-high vacuum conditions in Penning-Malmberg traps, where the time evolution of the system is monitored for very long times by means of electrostatic and optical diagnostic systems. Complex (dusty) plasmas are ionized gases that contain a distribution of micrometer-sized particles with a surface charge of the order of a few thousand electron charges. The interplay between a wide range of scales in time and space gives rise to new characteristic physical phenomena. Laboratory complex plasmas generally satisfy a global (quasi-)neutrality condition. A different concept is represented by a non-neutral complex plasma. To investigate the dynamics of this system, we are currently developing the DuEl (Dust-Electron) device, where negatively charged dust particles will be present together with a population of electrons. The experimental set-up will include a dust injection system and a Penning-Malmberg trap for the confinement of the dust-contaminated electron plasma. We describe here the main physical aims of the project and the present design of the apparatus. To support the experimental project, we have been developing a specifically tailored two-dimensional 'hybrid' Particle-In-Cell code. Using polar cylindrical coordinates, the code aims to investigate the transverse dynamics of a magnetized electron plasma contaminated by a massive, charged species. A mass-less fluid approximation for the electron population is exploited, while the dust component is treated with a kinetic description, also including the gravitational force. The preliminary results of systematic studies on the effects of heavy (magnetized or non-magnetized) dust grains on the equilibrium and stability properties of the electron fluid are presented. The implementation of other characteristic phenomena of interest, e.g. residual gas friction and dust charge fluctuations, is also under development.

Rome, M.; Cavaliere, F.; Maero, G.; Paroli, B.; Pozzoli, R. [INFN Sezione di Milano and Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, I-20133 Milano (Italy); Cavenago, M. [INFN Laboratori Nazionali di Legnaro, Viale dell' Universita 2, I-35020 Legnaro (Italy); Ikram, M. [INFN Sezione di Milano and Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, I-20133 Milano, Italy and Department of Physics, Hazara University, 21300 Mansehra (Pakistan); Lepreti, F. [Dipartimento di Fisica, Universita della Calabria and CNISM Unita di Cosenza, Ponte P. Bucci 31C, I-87036 Rende (Italy)

2013-03-19

109

Diagnostic Protocol Used in Central Disease Investigation Laboratory Dhaka, Bangladesh  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present study was carried out during a period of four months at Central Disease Investigation Laboratory, Dhaka with the primary aim to measure the frequency of Gumboro in poultry based on sample submission and diagnostic protocol they have been using for poultry disease surveillance. The birds >30 days had a more frequency of Gumboro and the mortality was also comparatively higher in these group (15.66 risk ratio and 4.65 rate ratio). BV 300 strain was affected at a relatively higher rat...

Rashid, M. H.; Atikuzzaman, M.; Rahman, M. A.; Hoque, M. A.; Chowdhury, M. Y. E.

2003-01-01

110

Experimental Investigation of the Integral Constant in Steady Flow Conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An elaborate experimental system was designed and built in the Hydraulics Laboratory of Civil Engineering Department of Dokuz Eylul University, in order to study the velocity distribution by means of an Ultrasonic Velocity Profiler (UVP) over rough bed at different flow rates. The UVP which has t...

Gökçen Bombar; ?ükrü Mehmet Güney

2010-01-01

111

A Global Remote Laboratory Experimentation Network and the Experiment Service Provider Business Model and Plans  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents results from the IST KAII Trial project ReLAX - Remote LAboratory eXperimentation trial (IST 1999-20827), and contributes with a framework for a global remote laboratory experimentation network supported by a new business model. The paper presents this new Experiment Service Provider business model that aims at bringing physical experimentation back into the learning arena, where remotely operable laboratory experiments used in advanced education and training schemes are m...

2003-01-01

112

Laboratory Investigations on Estuary Salinity Mixing: Preliminary Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available Estuaries are bodies of water along the coasts that are formed when fresh water from rivers flows into and mixes with salt water from the ocean. The estuaries serve as a habitat to some aquatic lives, including mangroves. Human-induced activities such as dredging of shipping lanes along the bottom estuarine, the disposal of industrial wastes into the water system and shoreline development influence estuarine dynamics which include mixing process. These activities might contribute to salinity changes and further adversely affect the estuarine ecosystem. In order to study at the characteristics of the mixing between salt water (estuary and freshwater (river, a preliminary investigation had been done in the laboratory. Fresh water was released from one end of the flume and overflowing at weir at the other end. Meanwhile, salt water was represented by the red dye tracer released through a weir and intruded upstream as a gravity current. The isohalines are plotted to see the salinity patterns. Besides, to examine the spatial and temporal salinity profiles along the laboratory investigations, the plotted graphs have been made. The results show that the changes in salinity level along the flume due to mixing between fresh water and salt water. This showed typical salt-wedge estuary characteristics.

F. H. Nuryazmeen

2014-05-01

113

Experimental methods for laboratory-scale ensilage of lignocellulosic biomass  

International Nuclear Information System (INIS)

Anaerobic fermentation is a potential storage method for lignocellulosic biomass in biofuel production processes. Since biomass is seasonally harvested, stocks are often dried or frozen at laboratory scale prior to fermentation experiments. Such treatments prior to fermentation studies cause irreversible changes in the plant cells, influencing the initial state of biomass and thereby the progression of the fermentation processes itself. This study investigated the effects of drying, refrigeration, and freezing relative to freshly harvested corn stover in lab-scale ensilage studies. Particle sizes, as well as post-ensilage drying temperatures for compositional analysis, were tested to identify the appropriate sample processing methods. After 21 days of ensilage the lowest pH value (3.73 ± 0.03), lowest dry matter loss (4.28 ± 0.26 g. 100 g-1DM), and highest water soluble carbohydrate (WSC) concentrations (7.73 ± 0.26 g. 100 g-1DM) were observed in control biomass (stover ensiled within 12 h of harvest without any treatments). WSC concentration was significantly reduced in samples refrigerated for 7 days prior to ensilage (3.86 ± 0.49 g. 100 g?1 DM). However, biomass frozen prior to ensilage produced statistically similar results to the fresh biomass control, especially in treatments with cell wall degrading enzymes. Grinding to decrease particle size reduced the variance amongst replicates for pH values of individual reactors to a minor extent. Drying biomass prior to extraction of WSCs resulted in degradation of the carbohydrates and a reduced estimate of their concentrations. The methods developed in this study can be used to improve ensilage experiments and thereby help in developing ensilage as a storage method for biofuel production. -- Highlights: ? Laboratory-scale methods to assess the influence of ensilage biofuel production. ? Drying, freezing, and refrigeration of biomass influenced microbial fermentation. ? Freshly ensiled stover exhibited the most preferable characteristics. ? Frozen biomass was statistically similar to freshly ensiled stover. ? Modified phenol-sulfuric method provides appropriate results and better resolution.

2012-12-01

114

Laboratory investigation of dispensing systems for swormlure-4  

International Nuclear Information System (INIS)

Laboratory investigations of the release of the components of swormlure-4 from open bottles showed that release of dimethyldisulphide was unexpectedly rapid, whereas relative release rates of the other components were in line with their boiling points. Examination of release from sealed polythene sachet dispensers showed relatively rapid release of dimethyldisulphide, release of the carboxylic acids at medium rates and slow release of the other components, including the volatile butyl alcohols. Release rates from the sachets are known to depend upon thickness of the polythene and their surface area, and a system giving release rates for all the components suitable for attraction of screwworm in the field could be designed. This would comprise a thin-walled sachet for all the components except the dimethyldisulphide, and the latter in a commercially-available, thick-walled sachet. 10 figs, 1 tab

1992-02-01

115

Experimental Investigation of the Wind Turbine Blade Root Flow:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several methods from experimental to analytical are used to investigate the aerodynamics of a horizontal axis wind turbine. To understand 3D and rotational effects at the root region of a wind turbine blade, correct modeling of the flow field is essential. Aerodynamic models need to be validated by accurate experimental data. In this paper, the experimental results of the aerodynamic behavior of a model wind turbine blade, by focusing on the blade root flow, are presented. The measurements ar...

Akay, B.; Ferreira, C. S.; Bussel, G. J. W.

2010-01-01

116

CIEMAT's Experimental Activity in the Investigation of Severe Accidents  

International Nuclear Information System (INIS)

The CIEMAT has three medium and small scale experimental plants in the service of research into specific phenomena associated with severe accidents in nuclear power plants. Experimental investigation is supplemented with analytical type work for validating, improving and developing models which accurately estimate the phenomenology expected under severe accident conditions. (Author)

1999-01-01

117

Thermodiffusion in multicomponent hydrocarbon mixtures: Experimental investigations and computational analysis  

Science.gov (United States)

In an unprecedented experimental investigation, a ternary and a four component hydrocarbon mixture at high pressure have been studied in a nearly convection free environment to understand the thermodiffusion process. A binary mixture has also been investigated in this environment. Experimental investigations of the three mixtures have been conducted in space onboard the spacecraft FOTON-M3 thereby isolating the gravity-induced convection that otherwise interferes with thermodiffusion experiments on Earth. The experimental results have also been used to test a thermodiffusion model that has been calibrated based on the results of previous experimental investigations. It was found that with an increase in the number of components in the mixtures, the performance of the thermodiffusion model deteriorated. Computational analysis was also made to estimate the possible sources of errors. Simulations showed that the vibrations of the spacecraft could influence the estimates of thermodiffusion factors. It was also found that they are sensitive to slight variations in the temperature of the mixture.

Vanvaerenbergh, Stefan; Srinivasan, Seshasai; Saghir, M. Ziad

2009-09-01

118

Computer-Guided Experimentation-A New System for Laboratory Instruction.  

Science.gov (United States)

This paper reports the development, operation, and initial performance evaluations of an electrical engineering laboratory station equipped for computer-guided experimentation (CGE). A practical evaluation of the actual instructional value of two programed lessons utilizing this new system for laboratory instruction and experimentation is also…

Neal, J. P.; Meller, D. V.

119

Experimental Investigations of Hydrogen Purification by Purging through Metal Hydride  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In an experimental stand [1] for investigation of properties of hydrogen accumulating the materials investigated a new type of reactor cleaning and storage of hydrogen. The applicability of hydrogen purging through metal hydride beds for the purification from non-poisoning admixtures is studied experimentally. The main characteristics of the process together with the main technical barriers of the proposed technology are defined. Specially designed stainless steel continuous flow reactor fill...

Blinov D.V.; Malyshenko S.P.; Borzenko V.I.; Dunikov D.O.

2012-01-01

120

Experimental and theoretical investigation of pipe riser clamps  

International Nuclear Information System (INIS)

The experimental investigations--photoelastic as well as strain gage--of two types of pipe riser clamps to be used in nuclear and fossil power plants reveal the presence of large normal and shear stresses in the vicinity of the bend in type A. A rigorous finite element analysis is compared with the experimental result. A set of design recommendations is presented based on the investigation. (Author)

1978-04-20

 
 
 
 
121

ATTEMPTS TO ESTABLISH EXPERIMENTAL CYCLOSPORA CAYETANENSIS INFECTION IN LABORATORY ANIMALS  

Science.gov (United States)

Attempts were made to develop an animal model for Cyclospora cayetanensis to identify a practical laboratory host for studying human cyclosporiasis. Oocysts collected from stool of infected humans in the United States, Haiti, Guatemala, Peru and Nepal were held in potassium dich...

122

ATTEMPS TO ESTABLISH EXPERIMENTAL CYCLOSPORA CAYETANENSIS INFECTION IN LABORATORY ANIMALS  

Science.gov (United States)

Attemps were made to develop an animal model for Cyclospora cayetanensis to identify a practical laboratory host for studing human cyclosporiasis. Oocysts collected from stool of infected humans in the United States, Haiti, Guatemala, Peru, and Nepal were held in potassium dichro...

123

Experimental Investigation and Modeling of Integrated Tri-generation Systems  

Science.gov (United States)

Energy demand in the world is increasing with population growth and higher living standards. Today, the need for energy requires a focus on renewable sources without abandoning fossil fuels. Efficient use of energy is one of the most important tasks in modern energy systems to achieve. In addition to the energy need, growing environmental concerns are linked with energy is emerged. Multi-purpose energy generation allows a higher efficiency by generating more outputs with the same input in the same system. Tri-generation systems are expected to provide at least three commodities, such as heating, cooling, desalination, storable fuel production and some other useful outputs, in addition to power generation. In this study, an experimental investigation of gasification is presented and two integrated tri-generation systems are proposed. The first integrated tri-generation system (System 1) utilizes solar energy as input and the outputs are power, fresh water and hot water. It consists of four sub-systems, namely solar power tower system, desalination system, Rankine cycle and organic Rankine cycle (ORC). The second integrated tri-generation system (System 2) utilizes coal and biomass as input and the outputs are power, fuel and hot water. It consists of five sub-systems: gasification plant, Brayton cycle, Rankine cycle, Fischer-Tropsch synthesis plant and an organic Rankine cycle (ORC). Experimental investigation includes coal and biomass gasification, where the experimental results of synthesis gas compositions are utilized in the analysis of the second systems. To maximize efficiency, heat losses from the system should be minimized through a recovery system to make the heat a useful commodity for other systems, such as ORCs which can utilize the low-grade heat. In this respect, ORCs are first analyzed for three different configurations in terms of energy and exergy efficiencies altering working fluids to increase the power output. Among two types of coal and one type biomass tried in the laboratory scale experimental set-up, Tuncbilek-Omerler is found to be superior to Konya-Ilgin coal in terms of the highest amount of hydrogen in the synthesis gas composition. As biomass, wheat straw is gasified, which shows higher exergetic efficiency in comparison to Konya-Ilgin coal. Based on theoretical analysis conducted for the integrated systems, System 2 is found to be more efficient in terms of energy and exergy in comparison with System 1. However, when local needs are taken into account, fresh water can be a desirable useful output where solar irradiation is high. Both systems are compared to conventional and co-generation systems having the same inputs to quantify the improvement in efficiency. System 1 has an energy efficiency of 69% and an exergy efficiency of 58%, whereas System 2 has an energy efficiency of 71% and an exergy efficiency of 73%. When single generation is obtained from the same inputs, it is observed that the energy and exergy efficiencies drop drastically down to 34% and 42% for System 1; 33% and 42% for System 2, respectively.

Cetinkaya, Eda

124

Experimental study of the D-OSKIL mechanism for controlling the stick-slip oscillations in a drilling laboratory testbed  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The presence of harmful stick-slip oscillations in oil well drillstrings has attracted the attention of the control community in recent years. The control law named D-OSKIL mechanism which uses the weight on the bit (WoB) force as an additional control variable to extinguish limit cycles has been investigated. This paper reports experimental implementation of such a mechanism, in a laboratory testbed. We also provide details of the experimental process and the obtained drilling performance. R...

Lu, Haochuan; Dumon, Jonathan; Canudas Wit, Carlos

2009-01-01

125

Experimental Investigations on a Novel Chemical Looping Combustion Configuration  

International Nuclear Information System (INIS)

Chemical Looping Combustion (CLC) is a promising novel combustion technology involving inherent separation of carbon dioxide with minimum energy penalty. An oxygen carrier is employed to continuously transfer oxygen from the air reactor to the fuel reactor where the oxygen is delivered to the fuel. Consequently, direct contact between the air and fuel is prevented. The resulting flue gas is CO2-rich, without N2 dilution. The reduced oxygen carrier is then transported back to the air reactor for re-oxidation purposes, hence forming a chemical loop. Various CLC configurations have already been developed and tested on laboratory scales. However, more investigations are required to achieve feasible CLC processes. Among the different points to address, control of the solid circulation rate between the two reactors is of the highest importance regarding its effect on achievement of an appropriate oxygen transfer rate and solid oxidation degrees. Moreover, minimization of gas leakage between the fuel and air reactors is another important issue to be considered. A novel CLC configuration is proposed where reactions are carried out in two interconnected bubbling fluidized beds. Solid circulation rate control is achieved independently of gas flow rate in the reactors through use of pneumatic non-mechanical valves (L-valves). Moreover, loop-seals are employed to minimize gas leakage while transferring solids. Experimental results from operation of a 10 kWth equivalent cold prototype are presented in this paper. The effect of operating variables on the solid circulation rate, gas leakage between the two beds and the pressure balance on all of the process elements is studied. The results demonstrate stable solid circulation with efficient control of the solid flow rate and effective gas tightness of the system. (authors)

2011-01-01

126

Experimental investigations of hydrogen catalytic combustion plates at KCAST  

Energy Technology Data Exchange (ETDEWEB)

Catalytic combustion of hydrogen is considered to be one of the safest, cleanest and most efficient forms of utilizing hydrogen for heating purposes. At KACST, in order to find a general purpose catalytic combustion module, thorough application-oriented investigations were carried out upon different hydrogen catalytic combustion plates. In this paper, experimental setup, investigation procedures and study results are discussed in detail. (Author)

Al-Garni, M. [King Abdulaziz City for Science and Technology (KCAST), Riyadh (Saudi Arabia). Energy Research Inst.

1997-04-01

127

Physiological Experimentation with the Crayfish Hindgut: A Student Laboratory Exercise  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of the report is to describe dissection techniques for preparing the crayfish hindgut and to demonstrate how to make physiological recordings with a force transducer to monitor the strength of contraction. In addition, we demonstrate how to visually monitor peristaltic activity, which can be used as a bioassay for various peptides, biogenic amines and neurotransmitters. This preparation is amenable to student laboratories in physiology and for demonstrating pharmacological concept...

Cooper, Ann S.; Leksrisawat, Bonnie; Gilberts, Allison B.; Mercier, A. Joffre; Cooper, Robin L.

2011-01-01

128

Software to Enhance Hands-On Laboratory Experimentation  

Science.gov (United States)

This presentation from MATEC explains the transition from using software to getting hands-on experience in a lab. The laboratory setting in technology related courses is an integral part of the learning experience for the student. It takes the theory that is being learned in the lecture and applies that theory. The text books that are used in the lecture include a copy of either Multi Sim or Electronic Workbench. The software gives the student the ability to "build" the circuits that are under study without the hardware that is found in the lab. The students at Grambling State University are not utilizing the software in the beginning level classes. The students must start utilizing the software earlier in the educational career. To accomplish this, the students are starting to complete the lab assignments with software before going to the lab. By doing this, the students will know what to expect before starting lab. This can and hopefully will remove some confusion that the beginner level circuit student has when constructing a circuit. The next step to improving and enhancing the laboratory experience for the student is to add a computer system to each laboratory station. Each system will contain software and hardware that will connect the test instruments to the computer and perform a multitude of analysis functions. The software that has stimulated some interest is MatLab. MatLab includes curriculum for some of the following: digital signal processing, digital image processing, digital filters, signals and systems, speech processing, computer-controlled systems, applied digital signal processing, dynamic modeling of engineering systems, and continuous-time linear systems. In conclusion, the learning invention for this laboratory is to bring together the lecture and lab through the implementation of software and hardware. This was part of the Learning Invention Labs that MATEC held. Visit the MATEC.org homepage for more information.

Flinders, Shirley

2013-01-01

129

Laboratory investigations of arcing on W-coated graphite components  

International Nuclear Information System (INIS)

Results of laboratory experiments of arcing on graphite tiles coated by a W-layer are reported. The samples have been taken from coated tiles manufactured for ASDEX Upgrade (AUG). The motion of the arcs was observed by high-speed cameras. Additionally, sample plates have been exposed to collect macro-particles emitted by the arc. The eroded surfaces of the cathodes were investigated after experiment to characterize surface changes, tracks, and re-deposited particles. On the cathode strongly radiating immobile spots are observed by the cameras acting as sources of numerous macro-particles. At the surface large holes (diameter 17 ?m) are found that perforate the W-layer and extend into the graphite bulk. Subsequent arcs tend to locate at the pre-existing holes. Hence, locally the W-coating is quickly and effectively broken, the W erosion is enhanced as compared to bulk W, and carbon is locally liberated despite the existence of an undamaged W-coating outside the arcing region

2013-07-01

130

Laboratory investigations of arcing on W-coated graphite components  

Science.gov (United States)

Results of laboratory experiments of arcing on graphite tiles coated by a W-layer are reported. The samples have been taken from coated tiles manufactured for ASDEX Upgrade (AUG). The motion of the arcs was observed by high-speed cameras. Additionally, sample plates have been exposed to collect macro-particles emitted by the arc. The eroded surfaces of the cathodes were investigated after experiment to characterize surface changes, tracks, and re-deposited particles. On the cathode strongly radiating immobile spots are observed by the cameras acting as sources of numerous macro-particles. At the surface large holes (diameter 17 ?m) are found that perforate the W-layer and extend into the graphite bulk. Subsequent arcs tend to locate at the pre-existing holes. Hence, locally the W-coating is quickly and effectively broken, the W erosion is enhanced as compared to bulk W, and carbon is locally liberated despite the existence of an undamaged W-coating outside the arcing region.

Laux, M.; Siemroth, P.; Marx, M.; Neu, R.; Rohde, V.; Balden, M.; Endstrasser, N.

2013-07-01

131

Laboratory investigation of Hg release from flue gas desulfurization products.  

Science.gov (United States)

Flue gas desulfurization (FGD) is a process applied to remove acid deposition precursors from the coal combustion air stream. This process also removes mercury (Hg) resulting in accumulation of this element in FGD produced solids. This project investigated Hg release from FGD materials to the air and water. Hg concentrations in the synthetic leaching precipitation procedure extracts, designed to simulate rainwater pH conditions, were in general coal fly ash, which has been found to adsorb Hg from the air, FGD materials were found to release Hg to the air over time with the addition of water a dominant environmental factor promoting release. The chemistry of the atmosphere to which the FGD materials were exposed (i.e., air Hg concentration and presence of oxidants), as well as that of the material (i.e., salts removed), was found to influence the magnitude of emissions. Although this work showed a component of the Hg captured by the FGD process could be released to the air under laboratory conditions, the potential for release under disposal and beneficial use conditions needs to be determined. PMID:20420364

Gustin, Mae; Ladwig, Ken

2010-05-15

132

Photochemistry of Mercury and Organics in Sea Ice - Laboratory Investigations  

Science.gov (United States)

Sea-Ice may trap toxic pollutants such as mercury from the atmosphere and foster their discharge to the aquatic environment during melting periods. Once released to the ocean, the toxics can enter the food web. Here we present experiments on the chemical reactivity of mercury in the ice matrix that result in a re-emission of mercury to the atmosphere. Better knowledge of this process might help to improve global budgets of mercury. We describe a set of laboratory experiments where we quantified the light-driven mercury reduction in ice and its subsequent release from the ice matrix. The experiments focused on the effect of organic matter, such as benzophenone, oxalic acid, and humic acid on the reaction kinetics. The influence of halogen ions, pH and temperature was also investigated. This - to our knowledge- first description of the light-driven mercury reduction in ice showed that organic matter significantly enhances the reactivity. Reaction pathways are proposed to explain the observation. The results also indicate that the photolysis rate is significantly reduced in the presence of halogens at typical concentrations of sea water.

Bartels-Rausch, Thorsten; Krysztofiak, Giséle; Bernhard, Andreas; Schläppi, Manuel; Schwikowski, Margit; Ammann, Markus

2010-05-01

133

EXPERIMENTAL INVESTIGATION ON HIGH PERFORMANCE CONCRETE USING SILICAFUME AND FLYASH  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this experimental investigation is to study the behaviour of High Performance Concrete (HPC). In this investigation HPC was manufactured by usual ingredients such as cement, fine aggregate, coarse aggregate, water and mineral admixtures such as Silica Fume (SF) and Fly ash at various replacement levels and with Super Plasticizer. The water binder ratio (w/b) adopted is 0.30. The concrete used in this investigation was proportioned to target a mean strength of 60 MPa. Specimens ...

Kannan Kannan

2012-01-01

134

Theoretical and experimental investigation of n-butanol combustion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Biofuels, are attracting great interest as an alternative to fossil fuels. n-Butanol has surfaced as a potential biofuel, mainly because it does not suffer from the drawbacks, that the current most widely used biofuel, ethanol, does. In this work a theoretical and experimental investigation of n-butanol combustion is performed, while a baseline investigation of fundamental combustion properties of methane is carried out. The computational work involves the investigation of t...

Katsikadakos, Dimitrios

2013-01-01

135

Requirements for Real-Time Laboratory Experimentation over the Internet.  

Science.gov (United States)

A prototype system based on an inverted pendulum is used to study the Quality of Service and discuss requirements of remote-experimentation systems utilized for carrying out control engineering experiments over the Internet. This class of applications involves the transmission over the network of a variety of data types with their own peculiar…

Salzmann, C.; Latchman, H. A.; Gillet, D.; Crisalle, O. D.

136

Oak Ridge National Laboratory Research Reactor Experimenters' Guide  

Energy Technology Data Exchange (ETDEWEB)

The Oak Ridge National Laboratory has three multipurpose research reactors which accommodate testing loops, target irradiations, and beam-type experiments. Since the experiments must share common or similar facilities and utilities, be designed and fabricated by the same groups, and meet the same safety criteria, certain standards for these have been developed. These standards deal only with those properties from which safety and economy of time and money can be maximized and do not relate to the intent of the experiment or quality of the data obtained. The necessity for, and the limitations of, the standards are discussed; and a compilation of general standards is included.

Cagle, C.D. (comp.)

1982-10-01

137

Possible experimental investigation of the phenomenon of anomalous ionization  

International Nuclear Information System (INIS)

We discuss the possibility of investigating experimentally in the upper ionosphere the critical velocity phenomenon. This occurs when a cloud of neutral gas interacts with plasma in a transverse magnetic field. We determine the region in experimental parameter space (flow rate of the gas, plasma density, etc.) where we might anticipate the occurrence of a self-sustaining beam-plasma discharge. We consider quantitatively the dynamics of the discharge process

1986-11-01

138

Computational and Experimental Investigations of Boundary Layer Tripping  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Supersonic flow over a tapered body of revolution has been investigated both experimentally and numerically. The experimental study consisted of a series of wind tunnel tests on an ogive-cylinder body. Static pressure distributions on the body surfaces at several longitudinal cross sections, as well as the boundary layer profiles at various angles of attack have been measured. Further, the flow around the model was visualized using Schlieren technique. Tests with a natural...

2010-01-01

139

Computational and Experimental Investigations of Boundary Layer Tripping  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Supersonic flow over a tapered body of revolution has been investigated both experimentally and numerically. The experimental study consisted of a series of wind tunnel tests on an ogive-cylinder body. Static pressure distributions on the body surfaces at several longitudinal cross sections, as well as the boundary layer profiles at various angles of attack have been measured. Further, the flow around the model was visualized using Schlieren technique. Tests with a natural development of the ...

2010-01-01

140

Investigation of Sulfate Attack by Experimental and Thermodynamic Means  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work investigates sulfate attack in complex sulfate environments by exposing different binder types to various sulfate solutions and comparing predicted phase and volume changes with experimental data. The most important aspects of this work can be grouped in three topics: The comparison of the predicted volume increase with the experimentally observed length changes. This part of the work shows that volume increase cannot be linked direct...

2012-01-01

 
 
 
 
141

Experimental Investigation into Electrical Discharge Machining of Stainless Steel 304  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study presents the experimental investigation of the machining characteristics of austenitic stainless steel 304 through electric discharge machining. The effectiveness of the EDM process with stainless steel is evaluated in terms of the removal rate (MRR), the Tool Wear Rate (TWR) and the surface roughness of the work-piece produced. The experimental work is conducted utilizing Die Sinking electrical discharge machine of AQ55L model. Cylindrical copper electrode having a size of Ø19x37...

Rahman, M. M.; Khan, M. A. R.; Kadirgama, K.; Noor, M. M.; Bakar, R. A.

2011-01-01

142

Experimental investigation of radiation transmission through a water spray  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Radiation attenuation by a water spray is experimentally investigated. Spectral transmissivity measurements are performed between 1000 and 7000 cm-1 with an experimental device involving a Fourier transform spectrometer. The spray is produced by a so-called Tee-Jet 400067 nozzle for water pressure between 1.5 and 6 bars. Key features like mean attenuation levels due to absorption and scattering by droplets and complex absorption pattern by water vapor are identified. Known effect of attenuati...

Parent, Gilles; Boulet, Pascal; Gauthier, Se?gole?ne; Blaise, Je?ro?me; Collin, Anthony

2006-01-01

143

Experimental investigation of vitiation effects on supersonic combustor performance  

Science.gov (United States)

A significant problem for use of combustion heated facilities in ground laboratory studies of scramjet propulsion is that the resulting high enthalpy test air are seriously vitiated by several species, for example, H2O, CO2, CO, H, OH, O, and NO, which are not of representative or very few in actual atmosphere, so-called vitiation air relative to pure air. Combustion in such vitiation air stream can be influenced by chemical and physical effects due to the different species from actual atmosphere. Therefore, the ground-test results from such vitiated facilities should be properly analyzed and corrected before extrapolated to atmospheric flight condition. The primary goal of the present efforts is to assess the net effects of vitiation air on combustion process in a supersonic combustor. Based on the direct-connected test facility of Northwestern Polytechnical University, an experimental system is developed for comparative investigation of supersonic combustion in vitiation airstream and clean airstream, respectively. Specific species at well-controlled concentration are added to the clean airstream generated from resistance heater to synthesize the vitiation airstream, duplicating the test media in a combustion heated facility. The air total temperature at combustor entrance is about 850 K, typically simulating the Mach 4 flight condition. Details of the experiment system are present in this paper. With the newly constructing system, hydrogen, ethylene and kerosene fueled supersonic combustions with clean air and vitiation air stream are investigated. Individual and combined influences of H2O and CO2 at various concentrations are considered over a range of experiment condition. The combustion characteristics with clean and vitiation air stream are compared, and the influences of H2O and H2O/CO2 on supersonic combustion processes are discussed. Results show that, the combustion induced pressure rise can be significantly inhibited by H2O and/or CO2 vitiation . The direct extrapolation of vitiated test results to flight condition may possibly result in over-fueling combustion, even inlet unstart. The H2O and/or CO2 vitiation also influence the shock waves in the isolator, resulting in the tendency of supersonic combustion mode.

Li, Jianping; Song, Wenyan; Luo, Feiteng; Shi, Deyong

2014-03-01

144

Minimum Experimental Standards in the Laboratory Search for Gravity Effects  

International Nuclear Information System (INIS)

Peer-reviewed reports of experimental modifications of gravity over rotating superconductors (Podkletnov, 1992), or of a weight increase during cool-down of superconductors (Reiss, 2003), have stimulated considerable recent discussion. Precise descriptions of sample composition, ancillary apparatus and balance specifications were not given by Podkletnov. Accordingly, a carefully-designed replication (Hathaway, 2003) could not confirm the experimental findings possibly because detailed information was unavailable. On the other hand Tajmar et al. (Tajmar, 2005) failed to replicate previous results due to lack of serious analysis of weight measurements of solids in atmosphere and subject to buoyancy and wetting forces. Also an acceptable measuring technique and a detailed analysis of the sample's temperature excursions versus time were not performed. Both examples clearly indicate that minimum standards of experimental precision, accounting for boundary conditions, error analysis and thorough reporting of the experiment are necessary to distinguish a true anomaly from prosaic explanations and artefacts. We will discuss some types of errors that can occur and how standards of analysis and reporting should be improved to allow others a thorough physical understanding

2006-01-20

145

El rol de la enfermera en un departamento de Cirugía Experimental (The nurse role in an experimental surgery laboratory  

Directory of Open Access Journals (Sweden)

Full Text Available Los esfuerzos de enfermería en estos últimos años se han centrado en buscar la autonomía y conseguir la independencia de la profesión, tanto en el ejercicio profesional como en el desarrollo científico, lo que ha facilitado su apertura a otros campos del conocimiento, como es la investigativa. La Cirugía experimental constituye una disciplina muy importante de las ciencias biomédicas por las amplias posibilidades que ofrece en el campo de la investigación así como en el adiestramiento de los futuros cirujanos y la enseñanza de pre y postgrado y la dotación de personal en este es vital si se desea mantener esa actividad investigativa que permita resolver problemas de la clínica o susceptibles de la propia investigación, no dejando a un lado la docencia, así como la prestación de servicios a otros departamentos, instituciones, etc., por lo que es imprescindible contar con la presencia de una enfermera, o varias, en dependencia de la cantidad de quirófanos con que cuenta el Dpto. o Laboratorio en cuestión. Tal como en el área clínica, la enfermera en el departamento o laboratorio de cirugía experimental ejerce las tres etapas del perioperatorio, con la ayuda del equipo de trabajo. Estas son: preoperatorio, transoperatorio y postoperatorio. El objetivo de este trabajo es dar a conocer la importancia de la enfermera en el trabajo de un departamento o laboratorio de cirugía experimental. Un centro, departamento o laboratorio de Cirugía experimental que no cuente con una enfermera dentro de su dotación de personal, no podrá realizar un buen trabajo, pues en la atención quirúrgica la enfermera es tan imprescindible como el cirujano, con funciones independientes y a la vez complementarias The nursing efforts during the last few years have been directed specifically in finding autonomy and independence in the profession, not only professionally, but also in the scientific development. It has facilitated its spreading to many fields of knowledge, as it is the case of investigation. Experimental surgery is a very important discipline within the biomedical sciences due to the possibilities it offers in the field of research in training future surgeons and in teaching graduates and non graduates . Personnel working here are quite important to keep the research projects, so as to solve problems related to clinics or associated with investigation. All these aspects should be kept in mind but without letting aside teaching and assistance to other departments, institutions, etc. Having this in mind it is necessary to have a nurse or more than one, if possible, depending on the number of surgeons there exist in the department or laboratory. The aim of this research is to give information on the importance of nurses as collaborators in a department or laboratory of experimental surgery. A department of experimental surgery without a nurse, as part of the staff, will never be able to carry out a good job, because they are as indispensable as surgeons, with independent and complementary functions typical of their profession.

Ileana Macías Hernández

2006-07-01

146

Laboratory investigation of crushed salt consolidation and fracture healing  

International Nuclear Information System (INIS)

A laboratory test program was conducted to investigate the consolidation behavior of crushed salt and fracture healing in natural and artificial salt. Crushed salt is proposed for use as backfill in a nuclear waste repository in salt. Artificial block salt is proposed for use in sealing a repository. Four consolidation tests were conducted in a hydrostatic pressure vessel at a maximum pressure of 2500 psi (17.2 MPa) and at room temperature. Three 1-month tests were conducted on salt obtained from the Waste Isolation Pilot Plant and one 2-month test was conducted on salt from Avery Island. Permeability was obtained using argon and either a steady-state or transient method. Initial porosities ranged from 0.26 to 0.36 and initial permeabilities from 2000 to 50,000 md. Final porosities and permeabilities ranged from 0.05 to 0.19 and from <10"-"5 md to 110 md, respectively. The lowest final porosity (0.05) and permeability (<10"-"5 md) were obtained in a 1-month test in which 2.3% moisture was added to the salt at the beginning of the test. The consolidation rate was much more rapid than in any of the dry salt tests. The fracture healing program included 20 permeability tests conducted on fractured and unfractured samples. The tests were conducted in a Hoek cell at hydrostatic pressures up to 3000 psi (20.6 MPa) with durations up to 8 days. For the natural rock salt tested, permeability was strongly dependent on confining pressure and time. The effect of confining pressure was much weaker in the artificial salt. In most cases the combined effects of time and pressure were to reduce the permeability of fractured samples to the same order of magnitude (or less) as the permeability measured prior to fracturing

1987-01-01

147

Laboratory investigation of crushed salt consolidation and fracture healing  

Energy Technology Data Exchange (ETDEWEB)

A laboratory test program was conducted to investigate the consolidation behavior of crushed salt and fracture healing in natural and artificial salt. Crushed salt is proposed for use as backfill in a nuclear waste repository in salt. Artificial block salt is proposed for use in sealing a repository. Four consolidation tests were conducted in a hydrostatic pressure vessel at a maximum pressure of 2500 psi (17.2 MPa) and at room temperature. Three 1-month tests were conducted on salt obtained from the Waste Isolation Pilot Plant and one 2-month test was conducted on salt from Avery Island. Permeability was obtained using argon and either a steady-state or transient method. Initial porosities ranged from 0.26 to 0.36 and initial permeabilities from 2000 to 50,000 md. Final porosities and permeabilities ranged from 0.05 to 0.19 and from <10/sup -5/ md to 110 md, respectively. The lowest final porosity (0.05) and permeability (<10/sup -5/ md) were obtained in a 1-month test in which 2.3% moisture was added to the salt at the beginning of the test. The consolidation rate was much more rapid than in any of the dry salt tests. The fracture healing program included 20 permeability tests conducted on fractured and unfractured samples. The tests were conducted in a Hoek cell at hydrostatic pressures up to 3000 psi (20.6 MPa) with durations up to 8 days. For the natural rock salt tested, permeability was strongly dependent on confining pressure and time. The effect of confining pressure was much weaker in the artificial salt. In most cases the combined effects of time and pressure were to reduce the permeability of fractured samples to the same order of magnitude (or less) as the permeability measured prior to fracturing.

1987-01-01

148

Laboratory Investigations of the Formation of Superhydrogenated PAHs  

Science.gov (United States)

We present experimental investigations of the formation of superhydrogenated polycyclic aromatic hydrocarbons (PAHs) through exposure of neutral PAHs to atomic hydrogen. Post irradiation thermal desorption measurements demonstrate that it is possible to form superhydrogenated coronene molecules with surprisingly high numbers of additional H atoms. We observe species with in excess of 20 additional H atoms, approaching the fully hydrogenated limit, perhydrocoronene. Scanning tunneling microscopy (STM) measurements provide insight into the changes to the electronic structure of the coronene species as a result of the hydrogenation process. Submolecular structure observed in the STM images indicates that a range of different sites on the coronene molecule are hydrogenated. The formation of PAHs with such high degrees of superhydrogenation may have important implications for molecular hydrogen formation in the ISM. Recent density functional theory calculations1 have indicated the efficient formation of H2 through a combination of hydrogenation and abstraction reactions involving neutral PAHs and their superhydrogenated forms. Although previous measurements by Menella2 have demonstrated the efficiency of both H addition and subsequent abstraction reactions involving a complex aromatic carbon grain mimic, the measurements reported here provide the first direct observation of neutral PAH superhydrogenation by H atom addition. The role played by PAHs in H2 formation is suggested by observations of a correlation between H2 and PAHs abundances in photodissociation regions3. Routes to H2 involving PAH cations have been investigated by several groups4-6 and the role played by anions has also been considered7. The present work demonstrates that neutral PAHs may also provide a formation route for this most important of interstellar molecules.

Thrower, J.; Friis, E.; Jorgensen, B.; Nilsson, L.; Baouche, S.; Balog, R.; Cassidy, A.; Hornekae, L.

2011-05-01

149

Laboratory Investigation of Wave Breaking. Part II. Deep Water Waves.  

Science.gov (United States)

This study represents the first known attempt to examine in some detail the flow dynamics of the terminal growth and breaking of periodic surface waves in deep water, under controlled and reproducible laboratory conditions. This work was considered a nece...

W. G. Van Dorn S. E. Pazan

1975-01-01

150

Critical Mass Laboratory Solutions Precipitation, Calcination, and Moisture Uptake Investigations  

International Nuclear Information System (INIS)

Laboratory work was conducted at Pacific Northwest National Laboratory and the Plutonium Process Support Laboratory of the Plutonium Finishing Plant (PFP) to study flowsheet conditions to selectively precipitate plutonium oxalate from uranium-bearing Critical Mass Laboratory (CML) solutions in the PFP precipitation apparatus and to dry and calcine the resulting filtercake to generate a stable plutonium oxide bearing powder (as judged by loss-on-ignition measurements) in the ambient humidity of the remote mechanical C (RMC) line in the PFP. Based on these studies with simulated and genuine CML solutions and various constituent materials, process conditions were recommended to the PFP under which the product powders can reasonably be expected to pass the DOE-STD-3013 moisture criterion when packaged in the RMC line at relative humidity up to 80%

2002-01-01

151

Critical Mass Laboratory Solutions Precipitation, Calcination, and Moisture Uptake Investigations  

Energy Technology Data Exchange (ETDEWEB)

Laboratory work was conducted at Pacific Northwest National Laboratory and the Plutonium Process Support Laboratory of the Plutonium Finishing Plant (PFP) to study flowsheet conditions to selectively precipitate plutonium oxalate from uranium-bearing Critical Mass Laboratory (CML) solutions in the PFP precipitation apparatus and to dry and calcine the resulting filtercake to generate a stable plutonium oxide bearing powder (as judged by loss-on-ignition measurements) in the ambient humidity of the remote mechanical C (RMC) line in the PFP. Based on these studies with simulated and genuine CML solutions and various constituent materials, process conditions were recommended to the PFP under which the product powders can reasonably be expected to pass the DOE-STD-3013 moisture criterion when packaged in the RMC line at relative humidity up to 80%.

Delegard, Calvin H.; Sinkov, Sergey I.; McNamara, Bruce K.; Jones, Susan A.; Barney, Gary S.; Schmidt, Andrew J.; Sell, Rachel L.

2002-06-03

152

The hot cell laboratories for material investigations of the Institute for Safety Research  

Energy Technology Data Exchange (ETDEWEB)

Special facilities for handling and testing of irradiated specimens are necessary, to perform the investigation of activated material. The Institute for Safety Research has two hot cell laboratories: - the preparation laboratory and - the materials testing laboratory. This report is intended to give an overview of the available facilities and developed techniques in the laboratories. (orig.)

Viehrig, H.W.

1998-10-01

153

Experimental results of tomographic reconstruction on ONERA laboratory MCAO bench  

Science.gov (United States)

Classic Adaptive Optics (AO) is now a proven technique to correct turbulence for earth based astronomical telescopes. But the corrected Field of View (FoV) is however limited by the anisoplanatism effect. Many concepts of wide field AO systems are now under study, especially for ELT's instruments. These systems allow a tomographic reconstruction of the turbulent volume thanks to the use of several WaveFront Sensors (WFS). They can provide for instance a correction in a specific direction (Laser Tomography AO system) with one Deformable Mirror (DM) or in a wide FoV (Multi Conjugate AO system) with several DMs conjugated to different altitudes. The performance optimization of such complex systems raise s inevitably new questions in terms of calibration and control. We present our current developments on perform ance optimization of wide field AO system. We show that performance can be significantly improved with tom ographic control based on Linear Quadratic Gaussian control, compared to more standard methods. The associ ated calibration and system modeling strategy is described. The results presented here are the first experime ntal validations of LQG control in closed-loop MCAO and LTAO configurations. These tests have been performed on H OMER bench, recently developed at ONERA and devoted to MCAO and wide field AO laboratory research. Thi s bench implements two deformable mirrors and a wide field Shack-Hartmann WFS.

Costille, Anne; Petit, Cyril; Conan, Jean-Marc; Kulcsar, Caroline; Raynaud, Henri-Francois

154

Experimental investigation of hydrogen storage in capillary arrays  

Energy Technology Data Exchange (ETDEWEB)

We present the results of the experimental investigation of hydrogen storage in glass capillary arrays. It is demonstrated that quartz-epoxy capillary arrays can have extremely high gravimetric and volumetric capacity, exceeding US DOE 2010 target values. The new method of pressurized hydrogen loading and releasing is developed based on plugging up the capillaries with stoppers in high-pressure environment. (author)

Zhevago, N.K.; Denisov, E.I.; Glebov, V.I. [RRC Kurchatov Institute, Moscow 123182 (Russian Federation)

2010-01-15

155

Experimental Investigation of the Dispersion of Liquids by Ejection Atomizers  

Science.gov (United States)

This paper presents the results of an experimental investigation of the dispersivity of liquid droplets in the spray cone of ejection atomizers. The calculational droplet size distribution function was measured by the method of low angles of the probe laser radiation scattering indicatrix on a pneumohydraulic bench under cold blow conditions. The efficiency of the proposed circuit designs of atomizers has been analyzed.

Arkhipov, V. A.; Bondarchuk, S. S.; Evsevleev, M. Ya.; Zharova, I. K.; Zhukov, A. S.; Zmanovskii, S. V.; Kozlov, E. A.; Konovalenko, A. I.; Trofimov, V. F.

2013-11-01

156

Experimental and numerical investigation on two-phase flow instabilities  

Energy Technology Data Exchange (ETDEWEB)

Two-phase flow instabilities are experimentally and numerically studied within this thesis. In particular, the phenomena called Ledinegg instability, density wave oscillations and pressure drop oscillations are investigated. The most important investigations regarding the occurrence of two-phase flow instabilities are reviewed. An extensive description of the main contributions in the experimental and analytical research is presented. In addition, a critical discussion and recommendations for future investigations are presented. A numerical framework using a hp-adaptive method is developed in order to solve the conservation equations modelling general thermo-hydraulic systems. A natural convection problem is analysed numerically in order to test the numerical solver. Moreover, the description of an adaptive strategy to solve thermo-hydraulic problems is presented. In the second part of this dissertation, a homogeneous model is used to study Ledinegg, density wave and pressure drop oscillations phenomena numerically. The dynamic characteristics of the Ledinegg (flow excursion) phenomenon are analysed through the simulation of several transient examples. In addition, density wave instabilities in boiling and condensing systems are investigated. The effects of several parameters, such as the fluid inertia and compressibility volumes, on the stability limits of Ledinegg and density wave instabilities are studied, showing a strong influence of these parameters. Moreover, the phenomenon called pressure drop oscillations is numerically investigated. A discussion of the physical representation of several models is presented with reference to the obtained numerical results. Finally, the influence of different parameters on these phenomena is analysed. In the last part, an experimental investigation of these phenomena is presented. The designing methodology used for the construction of the experimental facility is described. Several simulations and a non-dimensional similitude analysis are used to support the design, regarding the occurrence of two-phase flow instabilities. Some experimental results are presented in order to validate the current design. A full characterisation of the pressure drop losses in the facility is presented. Both, distributed and local pressure drop losses are investigated and the experimental results are compared with the main correlations used in the literature for the analysis of pressure drop in two-phase flow systems. Finally, pressure drop and density wave oscillations are studied experimentally, with main focus on the interaction of these two oscillation modes. In addition, the influence of compressibility volumes on the stability limits for the density wave phenomenon is analysed.(Author)

Ruspini, Leonardo Carlos

2013-03-01

157

ASSESSMENT OF BACK PAIN: Part IV - Laboratory Investigations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Chiropractors and Osteopaths are routinely involved in the assessment and treatment of patients with back pain. An overview of pertinent laboratory studies is presented to facilitate a better understanding of the use and value of these procedures toward improved patient management and enhanced communication with other health care professionals, in particular medical practitioners, as some patients may benefit from a combined management approach.

1994-01-01

158

Ribose 5-Phosphate Isomerase Investigations for the Undergraduate Biochemistry Laboratory  

Science.gov (United States)

The enzyme ribose 5-phosphate isomerase (RpiA) has many features that make it attractive as a focal point of a semester-long, advanced biochemistry laboratory for undergraduate students. The protein can easily and inexpensively be isolated from spinach using traditional purification techniques. Characterization of RpiA enzyme activity can be…

Jewett, Kathy; Sandwick, Roger K.

2011-01-01

159

Experimental and analytical investigation of rotor bearing systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objectives of this investigation were to design and construct a high speed turbocharger test rig (TTR) to measure dynamics of angular contact ball bearing rotor system, and to develop a coupled dynamic model for the ball bearing rotor system to corroborate the experimental and analytical results. In order to achieve the objectives of the experimental aspect of this study, a test rig was designed and developed to operate at speeds up to 70,000 rpm. The rotating components (i.e. turbine whe...

2012-01-01

160

Experimental aspects of an investigation of macroscopic ductile failure criteria  

Energy Technology Data Exchange (ETDEWEB)

Experimental results for the ductile failure of 7075-T651 aluminum are presented. Four separate shapes were tested to investigate the importance that macroscopic effective shear stress, hydrostatic stress, and plastic strain play in describing ductile failure of materials. The specimens used were: thin wall torsion tubes to create a state of pure shear, uniform hollow tubes to create a state of uniaxial stress; hour-glass shaped hollow tubes to create a state of biaxial stress; and notched round bars to create a state of triaxial stress. Two proposed ductile failure criteria are discussed in conjunction with the experimental results presented.

Soo Hoo, M.S.; Benzley, S.E.; Priddy, T.G.

1981-03-01

 
 
 
 
161

Experimental investigations on dynamic effects in impact notch bending tests  

International Nuclear Information System (INIS)

The dynamic behaviour of three point bending samples under impact stresses is examined experimentally. Various measuring processes, above all the shadow optics etching process are used. A quasi-static analysis is made by a simple spring/mass model to describe the stress behaviour quantitatively. Based on this, the dynamic effects in model experiments are measured quantitatively with dynamic correction functions and are discussed with reference to the wave processes in the sample. A systematic view of the effect of the many system parameters on the dynamic stress behaviour is obtained. Finally, examples show that the results of this model investigation can be transferred to other experimental conditions. (orig./HP)

1985-01-01

162

Laboratory Investigation of Aerosol Formation in Combustion of Biomass  

International Nuclear Information System (INIS)

In this project the formation of aerosol particles and deposits in power plants during combustion of CO2-neutral fuels are investigated. For the experimental work a 173 cm long tubular furnace (diam=25 mm) with laminar flow is used. It is possible to control the temperature up to ? 1200 deg C in nine separate axial sections along the flue gas flow direction. In the first part of the reactor an inner tube is placed. In this inner tube a flow of inert nitrogen passes pellets of inert alumina impregnated with the salt to be volatilized (e.g. NaCl or KCl). The nitrogen gets saturated and by changing the temperature of the pellets it is possible to adjust the salt concentration in the gas. Other reactive gases (SO2, H2O, NO and O2/air) enter the reactor on the outside of the salt-containing alumina pipe. The temperature is kept constant in the first part of the reactor and is then decreased in the flow direction after a given length. The results obtained so far have shown that the homogeneous nucleation rate of pure salts depends on cooling rate, salt concentration and on the vapor pressure of the salt. Examples of results are shown at figure 1a. Here, two identical experiments are performed with two different salts. Since the vapor pressure of KCl is higher than for NaCl at the same temperature, a higher mass concentration of particles is obtained for this salt. Due to a lower salt concentration the number concentration of NaCl particles is higher, but the particles are smaller. The particles are analyzed with a number of instruments, including scanning mobility particle sizer, low pressure cascade impactor and transition electron microscopy. Experiments with introduction of nucleation seeds in the inlet gas have been performed, and it has been found that a suppression of homogeneous nucleation can be observed at rather low number concentrations of seeds. Homogeneous nucleation is favored by rapid cooling and the critical seed concentration for suppression of nucleation is highly dependent on the rate of cooling. Experiments with sulfation of potassium chloride have been performed. By high-temperature filtering it has been found that potassium sulfate is the nucleating agent in aerosol formation during biomass combustion. In the future, the more advanced alkali-sulfur-chloride chemistry will be studied and the mechanisms leading to aerosol formation under biomass combustion conditions in power plants will be studied. The results will be analyzed by model studies including Computational Fluid Dynamics

2004-11-11

163

Combined Numerical and Experimental Investigation of Progressive Failure of Composites  

CERN Multimedia

The combination of Finite Element Method (FEM) simulation and experimental photo-elasticity provides both qualitative and quantitative information about the stress field in a polymer composite and particularly along the fibre-matrix boundary. Investigations were made using model specimens containing up to five parallel glass fibres loaded at angles from 0 to 15 degrees. The material properties of the geometrically equivalent FE models are calibrated using the experimental photoelastic outputs. In contrast to the experimental results, FE simulations provide full 3D stress fields. For verification purposes, the 3D stress fields are reduced to two-dimensional synthetic photoelastic phase images, showing good agreement. Furthermore, detailed studies on the components of the stress tensor, particularly statements concerning the shear transmitted by fibre-matrix boundary, progressive fibre failure and the effect of load angle variation are presented.

Deuschle, H M; Gerhard, H; Busse, G; Kröplin, B H

2004-01-01

164

Investigation of friction hysteresis using a laboratory-scale tribometer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The current paper addresses the characterization of dynamic friction by using a laboratory-scale tribometer. A special post-processing script in MatLab has been developed in order to analyse the data from the experiments. A sine wave signal for the velocity is imposed, with three different frequencies and, consequently, acceleration and deceleration rates. A friction material from brakes, with nominal contact area of 254 mm², was subjected to sliding against a commercially available brake di...

Neis, Patric Daniel; Baets, Patrick; Perez Delgado, Yeczain; Ferreira, Ney Francisco

2011-01-01

165

Numerical and laboratory investigations of transient and steady-state flow in a fractured core  

International Nuclear Information System (INIS)

An improved understanding of the ability of fractures to transmit water at matric potentials less than zero is essential for evaluating the ability of the rocks of Yucca Mountain, Nevada, to safely isolate nuclear waste. Numerical and experimental investigations of this subnuclear waste. Numerical and experimental investigations of this subject will help substantiate flux estimates of both liquid water and water vapor at Yucca Mountain, aid in assessing the effectiveness of capillary barriers at the contact between nonwelded and fractured welded units, and may provide insight as to the manner in which flow may become concentrated along specific pathways through a network of fractures under conditions of partial saturation. This paper summarizes some of the numerical and laboratory investigations that have been conducted at the US Geological Survey in Denver on a core of welded tuff containing a single fracture parallel to the core axis. The objectives of these investigations were to (1) explore the possibility that the unsaturated hydrologic properties of a fracture could be estimated by applying inverse techniques to the results of transient imbibition experiments, and (2) evaluate the accuracy of estimates of unsaturated fracture hydrologic properties derived from transient tests or numerical modeling through direct steady-state measurements. The core examined in these experiments is 0.0699 m long and has a radius of 0.0208 m. It was obtained from the open-quotes columnar zoneclose quotes of the Tiva Canyon member of the Paintbrush Tuff near Wren Wash on Yucca Mountain. 10 refs., 12 figs

1993-06-01

166

Experimental and numerical investigation of orbital atherectomy: absence of cavitation  

Directory of Open Access Journals (Sweden)

Full Text Available A definitive, quantitative investigation has been performed to determine whether orbital atherectomy gives rise to cavitation. The investigation encompassed a synergistic interaction between in vitro experimentation and numerical simulation. The experimentation was performed in two independent fluid environments: 1 a transparent tube having a diameter similar to that of the superficial femoral artery and 2 a large, fluid-filled, open-topped container. All of the experimental and simulation work was based on the geometric model of the Diamondback 360 atherectomy device (Cardiovascular Systems, Inc., St. Paul, MN. Rotational speeds ranged from 80,000 to 214,000 rpm. The presence or absence of cavitation in the experiments was assessed by means of high-speed photography. The photographic images clearly display the fact that there was no cavitation. Flow visualization revealed the presence of fluid flows driven by pressure gradients created by the geometry of the rotating crown. The numerical simulations encompassed the fluid environments and the operating conditions of the experiments. The key result of the numerical simulation is that the minimum fluid pressure due to the rotational motion was approximately 50 times greater than the saturation vapor pressure of the fluid. Since the onset of cavitation requires that the fluid pressure falls below the saturation vapor pressure, the computational outcome strongly supports the experimental findings.

Ephraim M. Sparrow

2010-11-01

167

Experimental investigation of contact resistance across pressed lead and aluminum  

International Nuclear Information System (INIS)

In the proposed production of Accelerator Production of Tritium (APT) blanket module, lead will be encased in aluminum cladding. Energy transfer rate from the lead to the cooling water will be a function of the contact resistance between lead and aluminum. No data for contact resistance for this application exists in the literature. An experimental investigation has been conducted to determine thermal contact resistance between lead and aluminum in vacuum environment and also investigate the effect of pressure, surface roughness, and interface temperature on the contact resistance. The contact resistance decreases with the increase in contact pressure. Interface temperature and surface roughness do not affect the contact resistance significantly. There is slight increase in contact conductance with increasing temperature. The experimental results are generally well within acceptable accuracy and the data should be a good reference for the APT model

2000-01-01

168

Experimental investigation of contact resistance across pressed lead and aluminum  

Energy Technology Data Exchange (ETDEWEB)

In the proposed production of Accelerator Production of Tritium (APT) blanket module, lead will be encased in aluminum cladding. Energy transfer rate from the lead to the cooling water will be a function of the contact resistance between lead and aluminum. No data for contact resistance for this application exists in the literature. An experimental investigation has been conducted to determine thermal contact resistance between lead and aluminum in vacuum environment and also investigate the effect of pressure, surface roughness, and interface temperature on the contact resistance. The contact resistance decreases with the increase in contact pressure. Interface temperature and surface roughness do not affect the contact resistance significantly. There is slight increase in contact conductance with increasing temperature. The experimental results are generally well within acceptable accuracy and the data should be a good reference for the APT model.

Smith, A.C.

2000-03-22

169

Experimental investigation of mass recovery adsorption refrigeration cycle  

Energy Technology Data Exchange (ETDEWEB)

The study investigates the performance of silica gel-water adsorption refrigeration cycle with mass recovery process by experimental prototype machine. In an adsorption refrigeration cycle, the pressures in adsorber and desorber are different. The mass recovery cycle utilizes the pressure difference to enhance the refrigerant mass circulation. Moreover, novel cycle was proposed for improvement of cooling output. In our previous study, simulation analysis shows that mass recovery cycle has the advantage over conventional single-stage. Experiments with prototype machine were conducted to investigate the performance improvement of mass recovery cycle in the present paper. Specific cooling power (SCP) and coefficient of performance (COP) were calculated with experimental data to analyze the influences of operating conditions. The proposed cycle was compared with the single-stage cycle in terms of SCP and COP. The results show that SCP of mass recovery cycle is superior to that of conventional cycle and mass recovery cycle is effective with low temperature heat source. (author)

Akahira, A.; Amanul Alam, K.C.; Hamamoto, Y.; Akisawa, A.; Kashiwagi, T. [Tokyo University of A and T (Japan). Department of Mechanical Systems Engineering

2005-06-01

170

Experimental and theoretical investigation of high gradient acceleration  

International Nuclear Information System (INIS)

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-AC02-91-ER40648, ''Experimental and Theoretical Investigations of High Gradient Acceleration''. This grant supports three research tasks: Task A consists of the design, fabrication and testing of a 17GHz RF photocathode gun, which can produce 2ps electron pulses with up to 1nC of charge at 2MeV energy and at a 1OHz repetition rate. Task B supports the testing of high gradient acceleration at 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tasks and on critical physics issues for the development of high energy linear colliders

1993-01-01

171

Experimental investigations on solar chimney for room ventilation  

Energy Technology Data Exchange (ETDEWEB)

Experimental investigations on a small size solar chimney show that the rate of ventilation increases with increase of the ratio between height of absorber and gap between glass and absorber. This finding is in agreement with results of the steady-state mathematical model developed for analysis of such systems. Nine different combination of absorber height and air gap have been investigated on the experimental set-up. Highest rate of ventilation induced with the help of solar energy was found to be 5.6 air change per hour in a room of 27m{sup 3}, at solar radiation 700W/m{sup 2} on vertical surface with the stack height-air gap ratio of 2.83 for a 1m high chimney. (author)

Mathur, Jyotirmay; Mathur, Sanjay; Jain, Meenakshi; Anupma, [Malaviya National Institute of Technology, Jaipur 302 017 (India); Bansal, N.K. [Center for Energy Studies, Indian Institute of Technology, New Delhi 110 016 (India)

2006-08-15

172

Experimental and theoretical investigation of high gradient acceleration  

International Nuclear Information System (INIS)

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-FG0291ER-40648. ''Experimental and Theoretical Investigations of High Gradient Acceleration.'' This grant supports three research tasks: Task A consists of the design and fabrication of a 17GHz of photocathode gun, Task B supports the testing of high gradient acceleration using a 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tasks and on critical physics issues for the development of high energy linear colliders. This report is organized as follows. The development of an rf gun design and research progress on the picosecond laser system is summarized in Sec. 2, the status of the studies of the LBL/Haimson high gradient structure, using a 50 MW free-electron laser is summarized in Sec. 3, and theoretical research progress is described in Sec. 4. Supporting material is contained in Appendices A-G

1992-01-01

173

Experimental Investigations of Generalized Predictive Control for Tiltrotor Stability Augmentation  

Science.gov (United States)

A team of researchers from the Army Research Laboratory, NASA Langley Research Center (LaRC), and Bell Helicopter-Textron, Inc. have completed hover-cell and wind-tunnel testing of a 1/5-size aeroelastically-scaled tiltrotor model using a new active control system for stability augmentation. The active system is based on a generalized predictive control (GPC) algorithm originally developed at NASA LaRC in 1997 for un-known disturbance rejection. Results of these investigations show that GPC combined with an active swashplate can significantly augment the damping and stability of tiltrotors in both hover and high-speed flight.

Nixon, Mark W.; Langston, Chester W.; Singleton, Jeffrey D.; Piatak, David J.; Kvaternik, Raymond G.; Bennett, Richard L.; Brown, Ross K.

2001-01-01

174

Experimental and Numerical Investigation of Therapeutic Ultrasound Angioplasty  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Therapeutic ultrasound angioplasty is an emerging minimally invasive cardiovascular surgical procedure that involves the delivery of ultrasonic displacements to the distal-tip of small diameter wire waveguides. The ultrasonic distal-tip displacements affect atherosclerotic plaque and thrombus by direct contact ablation, pressure wave components and cavitation, in addition to an acoustic streaming event around the distal-tip. This study uses experimental and numerical methods to investigate ul...

2005-01-01

175

Experimental and numerical investigation of therapeutic ultrasound angioplasty  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Therapeutic ultrasound angioplasty is an emerging minimally invasive cardiovascular surgical procedure that involves the delivery of ultrasonic displacements to the distal-tip of small diameter wire waveguides. The ultrasonic distal-tip displacements affect atherosclerotic plaque and thrombus by direct contact ablation, pressure wave components and cavitation, in addition to an acoustic streaming event around the distal-tip. This study uses experimental and numerical methods to investigate ul...

2005-01-01

176

Contract design and insurance fraud: An experimental investigation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper investigates the impact of insurance contract design on the behavior of filing fraudulent claims in an experimental setup. We test how fraud behavior varies for insurance contracts with full coverage, a straight deductible or variable premiums (bonus-malus contract). In our experiment, filing fraudulent claims is a dominant strategy for selfish participants, with no psychological costs of committing fraud. While some people always commit fraud, a substantial share of people only oc...

2010-01-01

177

Experimental and theoretical investigation of anaerobic fluidized bed biofilm reactors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work presents an experimental and theoretical investigation of anaerobic fluidized bed reactors (AFBRs). The bioreactors are modeled as dynamic three-phase systems. Biochemical transformations are assumed to occur only in the fluidized bed zone. The biofilm process model is coupled to the system hydrodynamic model through the biofilm detachment rate; which is assumed to be a first-order function of the energy dissipation parameter and a second order function of biofilm thickness. Non-act...

2009-01-01

178

Surface plasmon resonance of Ag organosols: Experimental and theoretical investigations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this paper is to investigate and compare the changes in surface plasmon resonance (SPR) of silver (Ag) hydrosol and organosols obtained by experimental and theoretical approaches. Silver nanoparticles (Ag NPs) of 5 ± 1.5 nm in diameter were prepared in water by reduction of silver nitrate with sodium borohydride. Nanoparticles were subsequently transferred into different organic solvents (chloroform, hexane, toluene, 1,2-dichlorobenzene) using oleylamine as a transfer agent....

Vukoje Ivana; Božani? Dušan; Džunuzovi? Jasna; Bogdanovi? Una; Vodnik Vesna

2012-01-01

179

Experimental and Numerical Investigations of Ice-Structure Interaction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ice interacting with offshore structures is of major engineering concern in areas where human activities and (seasonal) sea ice coexist. This thesis deals with experimental as well as numerical investigations of (level) ice-structure interaction and the typical processes associated with it.

 

Ice barriers, for the purpose of protecting offshore drilling units and production structures in shallow ice infested wat...

Gu?rtner, Arne

2009-01-01

180

Experimental Investigation of Turbulence Specifications of Turbidity Currents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present study investigates the turbulence characteristic of turbidity current experimentally. The three-dimensional Acoustic-Doppler Velocimeter (ADV) was used to measure the instantaneous velocity and characteristics of the turbulent flow. The experiments were conducted in a three-dimensional channel for different discharge flows, concentrations, and bed slopes. Results are expressed at various distances from the inlet, for all flow rates, slopes and concentrations as...

Firoozabadi, B.; Afshin, H.; Bagherpour, A.

2010-01-01

 
 
 
 
181

Theoretical and experimental investigations of electron attachment to biomolecules  

International Nuclear Information System (INIS)

In our age, humans are increasingly often exposed to radiation which can damage important biomolecules. Such defects are generated also via slow secondary electrons. In the present thesis basic effects of electron attachment to glycine, valine and proline in gasphase are investigated. Both experimental and theoretical methods are combined to reveal the nature of the underlying processes in gas phase and microsolvation. Also results of electron attachment to musk ketone and 2,4-dinitrotoluene are presented. (author)

2009-01-01

182

Experimental investigation of the serum albumin fascia microstructure  

Science.gov (United States)

The results of theoretical and experimental investigation of biological liquids are reported. Structural effects observed in fascias are considered with account of the molecular features of albumin and the concept of supramolecular organization of polymers. It is revealed that the morphology of human serum albumin fascias depends on the concentration and quality of the solvent. It is shown that the water-salt fascias of albumin are more structured than water solutions with the same concentration.

Buzoverya, M. E.; Shcherbak, Yu. P.; Shishpor, I. V.

2012-09-01

183

Experimental and Numerical Investigation of 2D Sloshing with Slamming  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Partially filled tanks can experience sloshing in several practical circumstances. This is a resonance phenomenon where the free-surface can highly deform. The liquid will move back and forth rising along the side walls, possibly impacting against the roof. Impact on a side tank wall may also occur,e. g. in shallow water conditions. Resulting slamming loads are of main concern. A synergic experimental-numerical investigation of the sloshing flows is currently performed. Here the main focus is...

2004-01-01

184

Experimental and Numerical Investigations of Friction Rings Damping of Blisks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The use of friction ring dampers for integrally bladed disks (blisks) is investigated numerically and experimentally in this paper. A test rig was developed and consists in an industrial HP compressor blisk rotating inside a vacuum chamber. Excitation is produced through piezoelectric actuators and measured data are obtained from strain gauges. Non-linear resonance curves obtained by stepped sine tests are studied. Interesting phenomena on the behaviour of this damping technology are obtained...

2008-01-01

185

Heat transfer crisis on sintered porous surfaces – experimental investigations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

There were presented the results of theoretical analysis of boiling heat transfer on heating surfaces covered with thin-layered capillary porous structures. The paper discussed the results of experimental investigations into intralayer boiling crisis and accompanying phenomena. It was observed that the structural parameters of the porous covering affected the course of the process. Hysteresis phenomenon manifested itself when the heat flux initiating intralayer heat crisis was reached. The cr...

Wojcik Tadeusz Michal

2012-01-01

186

Experimental Investigations of Clustering in Low Density Nuclear Matter  

International Nuclear Information System (INIS)

The formation of clusters in low density matter formed in near Fermi energy heavy ion collisions has been investigated using the NIMROD multi-detector at Texas A and M University. Emphasis is on elucidation of the low density equation of state. Temperature and density dependent symmetry free energies derived from isoscaling analyses of the yields of nuclei with A?4 are far above those obtained in common effective interaction calculations, reflecting the cluster formation. A possible extensionof the experimental techniques to investigations of nuclear Bose condensates is also discussed.

2010-11-24

187

Experimental investigations of DC-SC photoinjector at Peking University  

International Nuclear Information System (INIS)

We report the progress of the DC-SC photoinjector at Peking University. This is a compact electron gun integrating a DC Pierce gun with a 1.3 GHz superconducting cavity. The photoinjector is designed to provide an electron beam having an average current of 1 mA with the energy of 2.61 MeV and normalized rms transverse emittance of 3 mm mrad. The test facility has been completely installed in our laboratory. The photocathode preparation chamber can produce Cs2Te and Cs3Sb cathodes, and the laser system can provide laser pulses with 532 or 266 nm wavelength at an 81.25 MHz repetition rate. The timing jitter of less than 1 ps between the laser and RF power has been achieved by using a timing stabilizer. A new method using 'duo image pattern' of Cherenkov radiation will be commissioned to measure beam emittance. This paper summarizes some of the ongoing experimental activities

2004-08-01

188

Laboratory prototype for experimental validation of MR-guided radiofrequency head and neck hyperthermia  

Science.gov (United States)

Clinical studies have established a strong benefit from adjuvant mild hyperthermia (HT) to radio- and chemotherapy for many tumor sites, including the head and neck (H&N). The recently developed HYPERcollar allows the application of local radiofrequency HT to tumors in the entire H&N. Treatment quality is optimized using electromagnetic and thermal simulators and, whenever placement risk is tolerable, assessed using invasively placed thermometers. To replace the current invasive procedure, we are investigating whether magnetic resonance (MR) thermometry can be exploited for continuous and 3D thermal dose assessment. In this work, we used our simulation tools to design an MR compatible laboratory prototype applicator. By simulations and measurements, we showed that the redesigned patch antennas are well matched to 50 ? (S11compatibility of the setup. We conclude that the laboratory applicator provides the possibility for experimental assessment of the feasibility of hybrid MR-HT in the H&N region. This versatile design allows rigorous analysis of MR thermometry accuracy in increasingly complex phantoms that mimic patients' anatomies and thermodynamic characteristics.

Paulides, M. M.; Bakker, J. F.; Hofstetter, L. W.; Numan, W. C. M.; Pellicer, R.; Fiveland, E. W.; Tarasek, M.; Houston, G. C.; van Rhoon, G. C.; Yeo, D. T. B.; Kotek, G.

2014-05-01

189

Laboratory Investigation of Whistler Wave Resonances and Wave-Particle Interactions*  

Science.gov (United States)

Standing whistler wave patterns have been investigated in the Naval Research Laboratory's Space Physics Simulation Chamber. Partial reflection of the antenna-launched whistler waves from the chamber end boundaries sets up a combination of standing and traveling waves. By controlling the axial magnetic field strength profile, cyclotron absorption of the whistler waves can be induced before reflection occurs, leaving only the forward propagating waves. Under uniform axial magnetic field conditions, the addition of planar conducting grids across the vacuum chamber cross-section at the ends of the plasma column provides improved reflecting surfaces, improving the cavity Q. This experimental configuration is being used to investigate whistler wave-energetic electron interactions and pitch-angle scattering under simulated radiation belt plasma conditions. Electrons beams with controllable energy are produced by a hollow cathode source and introduced into the experimental region with selectable pitch angle. Experimental results from the whistler wave resonance and electron scattering experiments will be presented. *Work sponsored by the Office of Naval Research and the Defense Threat Reduction Agency.

Amatucci, W. E.; Tejero, E. M.; Cothran, C. D.; Blackwell, D.

2011-12-01

190

Promising lines of investigations in the realms of laboratory astrophysics with the aid of powerful lasers  

Science.gov (United States)

The results of work on choosing and substantiating promising lines of research in the realms of laboratory astrophysics with the aid of powerful lasers are presented. These lines of research are determined by the possibility of simulating, under laboratory conditions, problematic processes of presentday astrophysics, such as (i) the generation and evolution of electromagnetic fields in cosmic space and the role of magnetic fields there at various spatial scales; (ii) the mechanisms of formation and evolution of cosmic gamma-ray bursts and relativistic jets; (iii) plasma instabilities in cosmic space and astrophysical objects, plasma jets, and shock waves; (iv) supernova explosions and mechanisms of the explosion of supernovae featuring a collapsing core; (v) nuclear processes in astrophysical objects; (vi) cosmic rays and mechanisms of their production and acceleration to high energies; and (vii) astrophysical sources of x-ray radiation. It is shown that the use of existing powerful lasers characterized by an intensity in the range of 1018-1022 W/cm2 and a pulse duration of 0.1 to 1 ps and high-energy lasers characterized by an energy in excess of 1 kJ and a pulse duration of 1 to 10 ns makes it possible to perform investigations in laboratory astrophysics along all of the chosen promising lines. The results obtained by experimentally investigating laser plasma with the aid of the laser facility created at Central Research Institute of Machine Building (TsNIIMash) and characterized by a power level of 10 TW demonstrate the potential of such facilities for performing a number of experiments in the realms of laboratory astrophysics.

Belyaev, V. S.; Batishchev, P. A.; Bolshakov, V. V.; Elkin, K. S.; Karabadzhak, G. F.; Kovkov, D. V.; Matafonov, A. P.; Raykunov, G. G.; Yakhin, R. A.; Pikuz, S. A.; Skobelev, I. Yu.; Faenov, A. Ya.; Fortov, V. E.; Krainov, V. P.; Rozanov, V. B.

2013-04-01

191

Laboratory and field investigations of the performance of HPCC coatings  

Energy Technology Data Exchange (ETDEWEB)

High performance composite coatings (HPCC) are now being considered for use in commercial Canadian pipeline applications. HPCC is comprised of an inner layer of fusion bonded epoxy (FBE), a polyolefin adhesive layer, and an outer layer of medium density polyethylene. The layers are blended together to minimize interlayer delamination. This paper presented 2 approaches for assessing and predicting the field behaviour of HPCC. Standard CD disbondment tests were extended by subjecting laboratory test panels to a 2-stage degradation process designed to qualitatively simulate field service. An impedance-based technique called EISPlus was then used to measure the impedance and dielectric properties of the laboratory panels as well as HPCC coated pipe with 11 years of field exposure. Field measurements were then compared with earlier data to predict long-term HPCC performance. Results of the studies showed that there was no visual change in the appearance of the HPCC coating following the degradation procedures. Subsequent disbondment tests showed that there was no significant difference in disbondment radius for panels exposed to microbiologically active soils with or without the application of cathodic protection (CP) during soil exposure. The analysis suggested that additional damage was produced by field exposure. Predictions of the long-term condition of the FBE and HPCC pipeline coating were made by extrapolation of laboratory and field data. Results of the study demonstrated that the FBE coating will remain in excellent condition for approximately 30 years, while the HPCC coatings will remain in excellent condition for approximately 50 years. It was concluded that the information obtained using the EISPlus measurements will improve the ability to predict long-term coating performance as well as aid in environmental corrosion or cracking evaluations. 9 refs., 1 tab., 12 figs.

King, F.; Been, J. [NOVA Research and Technology Co., Calgary, AB (Canada); Worthingham, R.; Rubie, G. [TransCanada PipeLines Ltd., Calgary, AB (Canada)

2004-07-01

192

Investigations of Solar Prominence Dynamics Using Laboratory Simulations  

International Nuclear Information System (INIS)

Laboratory experiments simulating many of the dynamical features of solar coronal loops have been carried out. These experiments manifest collimation, kinking, jet flows, and S-shapes. Diagnostics include high-speed photography and x-ray detectors. Two loops having opposite or the same magnetic helicity polarities have been merged and it is found that counter-helicity merging provides much greater x-ray emission. A non-MHD particle orbit instability has been discovered whereby ions going in the opposite direction of the current flow direction can be ejected from a magnetic flux tube.

2008-01-01

193

How important are the dermatophytes? A clinical and laboratory investigation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dermatophyte infections were established in 6.9% of 640 unselected dermatology outpatients attending two district general hospitals in Cumbria over a six-month period. A clinical diagnosis of ringworm was confirmed in the laboratory in 43.1% of hospital and in 21.8% of a smaller series of general practice patients. No result of similar surveys have been published before., Even in a major stock-rearing area such as this, domestic pets appear to be a more important source of infection than the ...

Davies, D. G.; Deighton, J.; Paterson, W. D.

1982-01-01

194

Progress of investigations at the undeground research laboratory  

International Nuclear Information System (INIS)

Atomic Energy of Canada Limited (AECL) is constructing an Underground Research Laboratory (URL) in a previously undisturbed granitic pluton located near Lac du Bonnet, Manitoba as one of the major research projects within the Canadian Nuclear Fuel Waste Management Program. The research activities include site evaluation and underground experiment programs. The site evaluation program began in 1980 and is now in monitoring phase. The rock-mass and grounwater system have been characterized and modelled, and the actual response to URL excavation is being compared with the predictions. Underground experiments were conducted during shaft excavation, and some preliminary results are available

1985-01-01

195

A Laboratory Investigation of Turbulence Detection Using a Laser  

Science.gov (United States)

Calculations and experiments have been undertaken to determine the property of the backscattered laser-return signal that undergoes the most significant change in a turbulent region as compared with a nonturbulent region. If the turbulent region is composed mainly of air molecules, the detection of a shift in the frequency property appears to be the most promising. Therefore at this time the main effort at the Ames Research Center is focused on the implementation and laboratory evaluation of a clear-air turbulence detector utilizing a laser source and observing the frequency change.

Bourquin, Kent; Shigemoto, Fred H.

1965-01-01

196

The colloid investigations conducted at the Aespoe Hard Rock Laboratory during 2000-2004  

International Nuclear Information System (INIS)

In 2000, SKB decided to initiate an international colloid project at the Aespoe Hard Rock Laboratory in Sweden. The objectives of the colloid project are to: (i) study the role of bentonite as a colloid source, (ii) verify the background colloid concentration at Aespoe HRL and, (iii) investigate the potential for colloid formation/transport in natural groundwater concentrations. The experimental concepts for the colloid project are: laboratory experiments with bentonite, background field measurements of natural colloids, borehole specific bentonite colloid stability experiments and a fracture specific transport experiment. The activities concerning the laboratory experiments and background field measurements are described in this work; the other activities are ongoing or planned. The following conclusions were made: The bentonite colloid stability is strongly dependent on the groundwater ionic strength. Natural colloids are organic degradation products such as humic and fulvic acids, inorganic colloids (clay, calcite, iron hydroxide) and microbes. Microbes form few but large particles and their concentration increase with increasing organic carbon concentrations. The small organic colloids are present in very low concentrations in deep granitic groundwater. The concentrations can be rather high in shallow waters. The colloid concentration decreases with depth and salinity, since colloids are less stable in saline waters. The colloid content at Aespoe is less than 300 ppb. The colloid content at repository level is less than 50 ppb. The groundwater variability obtained in the boreholes reflects well the natural groundwater variability along the whole HRL tunnel

2005-01-01

197

The colloid investigations conducted at the Aespoe Hard Rock Laboratory during 2000-2004  

Energy Technology Data Exchange (ETDEWEB)

In 2000, SKB decided to initiate an international colloid project at the Aespoe Hard Rock Laboratory in Sweden. The objectives of the colloid project are to: (i) study the role of bentonite as a colloid source, (ii) verify the background colloid concentration at Aespoe HRL and, (iii) investigate the potential for colloid formation/transport in natural groundwater concentrations. The experimental concepts for the colloid project are: laboratory experiments with bentonite, background field measurements of natural colloids, borehole specific bentonite colloid stability experiments and a fracture specific transport experiment. The activities concerning the laboratory experiments and background field measurements are described in this work; the other activities are ongoing or planned. The following conclusions were made: The bentonite colloid stability is strongly dependent on the groundwater ionic strength. Natural colloids are organic degradation products such as humic and fulvic acids, inorganic colloids (clay, calcite, iron hydroxide) and microbes. Microbes form few but large particles and their concentration increase with increasing organic carbon concentrations. The small organic colloids are present in very low concentrations in deep granitic groundwater. The concentrations can be rather high in shallow waters. The colloid concentration decreases with depth and salinity, since colloids are less stable in saline waters. The colloid content at Aespoe is less than 300 ppb. The colloid content at repository level is less than 50 ppb. The groundwater variability obtained in the boreholes reflects well the natural groundwater variability along the whole HRL tunnel.

Laaksoharju, Marcus [Geopoint AB, Stockholm (Sweden); Wold, Susanna [Royal Inst. of Tech., Stockholm (Sweden). School of Chemical Science and Engineering, Nuclear Chemistry] (eds.)

2005-12-15

198

Environmental epidemiology applied to urban atmospheric pollution: a contribution from the Experimental Air Pollution Laboratory (LPAE  

Directory of Open Access Journals (Sweden)

Full Text Available Systematic investigation on the effects of human exposure to environmental pollution using scientific methodology only began in the 20th century as a consequence of several environmental accidents followed by an unexpected mortality increase above expected mortality and as a result of observational epidemiological and toxicological studies conducted on animals in developed countries. This article reports the experience of the Experimental Air Pollution Laboratory at the School of Medicine, University of São Paulo, concerning the respiratory system and pathophysiological mechanisms involved in responses to exposure to pollution using toxicological and experimental procedures, complemented by observational epidemiological studies conducted in the city of São Paulo. It also describes these epidemiological studies, pointing out that air pollution is harmful to public health, not only among susceptible groups but also in the general population, even when the concentration of pollutants is below the limits set by environmental legislation. The study provides valuable information to support the political and economic decision-making processes aimed at preserving the environment and enhancing quality of life.

André Paulo Afonso de

2000-01-01

199

Experimental investigation of transient thermoelastic effects in dynamic fracture  

International Nuclear Information System (INIS)

Thermoelastic effects in fracture are generally considered to be negligible at the benefit of the conversion of plastic work into heat. For the case of dynamic crack initiation, the experimental and theoretical emphasis has been put on the temperature rise associated with crack-tip plasticity. Nevertheless, earlier experimental work with polymers has shown that thermoelastic cooling precedes the temperature rise at the tip of a propagating crack (Fuller et al., 1975). Transient thermoelastic effects at the tip of a dynamically loaded crack have been theoretically assessed and shown to be significant when thermal conductivity is initially neglected. However, the fundamental question of the relation between crack initiation and thermal fields, both of transient nature, is still open. In this paper, we present an experimental investigation of the thermoelastic effect at the tip of fatigue cracks subjected to mixed-mode (dominant mode 1) dynamic loading. The material is commercial polymethylmethacrylate as an example of 'brittle' material. The applied loads, crack-tip temperatures and fracture time are simultaneously monitored to provide a more complete image of dynamic crack initiation. The corresponding evolution of the stress intensity factors is calculated by a hybrid-experimental numerical model. The results show that substantial crack-tip cooling develops initially to an extent which corroborates theoretical estimates. This effect is followed by a temperature rise. Fracture is shown to initiate during the early cooling phase, thus emphasizing the relevance of the phenomenon to dynamic crack initiation in this material as probably in other materials. (author)

1997-01-01

200

Numerical and experimental investigation of geometric parameters in projection welding  

DEFF Research Database (Denmark)

Resistance projection welding is widely used for joining of workpieces with almost any geometric combination. This makes standardization of projection welding impossible. In order to facilitate industrial applications of projection welding, systematic investigations are carried out on the geometric parameters by numerical modeling and experimental studies. SORPAS, an FEM program for numerical modeling of resistance welding, is developed as a tool to help in the phase of product design and process optimization in both spot and projection welding. A systematic experimental investigation of projection welding a disc to a ring with a triangular ring projection has been carried out to study the influence of the geometric parameters in various metal combinations. In these studies, SORPAS has been used as a supporting tool to understand the relationship of the parameters and the phenomena occurring in projection welding. Thickness of disc and ring, as well as height and angle of projection has been used as geometric parameters to obtain the best weld quality. The experiments have been used to determine the size of the welding lobe and the bond strength, while the numerical investigations have been used to show the temperature distribution using the different geometric parameters. The numerical simulations with SORPAS can explain the differences in the welding lobes and bond strength. This shows SORPAS as a strong tool in the product development of workpieces for resistance projection welding. Based on the numerical and experimental investigations of the geometric parameters in projection welding, guidelines for selection of the geometry and material combinations in product design are proposed. These will be useful and applicable to industry.

Kristensen, Lars; Zhang, Wenqi

2000-01-01

 
 
 
 
201

Experimental Investigation into Electrical Discharge Machining of Stainless Steel 304  

Directory of Open Access Journals (Sweden)

Full Text Available This study presents the experimental investigation of the machining characteristics of austenitic stainless steel 304 through electric discharge machining. The effectiveness of the EDM process with stainless steel is evaluated in terms of the removal rate (MRR, the Tool Wear Rate (TWR and the surface roughness of the work-piece produced. The experimental work is conducted utilizing Die Sinking electrical discharge machine of AQ55L model. Cylindrical copper electrode having a size of Ø19x37 mm and positive polarity for electrode (reverse polarity is used to machine austenitic stainless steel 304 materials. The work material holds tensile strength of 580 and 290 MPa as yield strength. The size of the work-piece was Ø22x30 mm. Investigations indicate that increasing the peak current increases the MRR and the surface roughness. The TWR increases with peak ampere until 150 ? sec pulse-on time. From the experimental results no tool wear condition is noted for copper electrode at long pulse-on time with reverse polarity. The optimal pulse-on time is changed with high ampere.

M.M. Rahman

2011-01-01

202

An experimental investigation of a household size trigeneration  

Energy Technology Data Exchange (ETDEWEB)

A household size trigeneration based on a small-scale diesel engine generator set is designed and realized in laboratory. Experimental tests are carried out to evaluate the performance and emissions of the original single generation (diesel engine generator); and the performances of the whole trigeneration including the diesel generator within the trigeneration system, the heat exchangers which are used to recover heat from engine exhaust, the absorption refrigerator which is driven by the exhaust heat; and the emissions from the whole trigeneration. Comparisons of the test results of two generations are also performed. The test results show that the total thermal efficiency of trigeneration reaches to 67.3% at the engine full load, comparing to that of the original single generation 22.1% only. Within the range of engine loads tested, the total thermal efficiencies of trigeneration are from 205% to 438% higher than that of the thermal efficiency of single generation. The CO{sub 2} emission per unit (kWh) of useful energy output from trigeneration is 0.401kg CO{sub 2}/kWh at the engine full load, compared to that of 1.22kg CO{sub 2}/kWh from single generation at the same engine load. Within the range of engine loads tested, the reductions of CO{sub 2} emission per unit (kWh) of trigeneration output are from 67.2% to 81.4% compared to those of single generation. The experimental results show that the idea of realizing a household size trigeneration is feasible; the design and the set-up of the trigeneration is successful. The experimental results show that the innovative small-scale trigeneration is able to generate electricity, produce heat and drive a refrigeration system, simultaneously from a single fuel (diesel) input. (author)

Lin, Lin [Nanning College for Vocational Technology, Nanning, Guangxi 530003 (China); Wang, Yaodong; Zeng, Shengchuo; Huang, Jincheng; He, Yunxin; Huang, Xiaodong [Mechanical Engineering College, Guangxi University, Nanning, Guangxi 530004 (China); Al-Shemmeri, Tarik; Ruxton, Tom; Turner, Stuart [Faculty of Computing, Engineering and Technology, Staffordshire University, Stafford ST18 0AD (United Kingdom)

2007-02-15

203

Laboratory investigation for estimation of seismic response of the ground  

International Nuclear Information System (INIS)

Laboratory measurements of soil properties can be used to supplement or confirm the results of field measurements. They are necessary to establish values of damping and modulus at strains larger than those that can be obtained in the field or to measure the properties of materials that do not exist in the field, such as soils to be compacted. The Dynamic Deformation Characteristics of the soil are used in order to calculate seismic response of ground, earth structures and structure-ground response. The improved cyclic triaxial equipment installed at CNRRS is used, when the dynamic properties of the soil must be obtained. In this test a cyclic load is applied to a column of soil over a number of cycles slowly enough that inertial effects do not occur. They are also used to express phenomenon that make soil to fail under seismic loading. Comparison of the obtained results with the well known international ones is presented. (authors)

2007-04-26

204

Role of routine laboratory investigations in preoperative evaluation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Traditionally, routine investigations prior to surgery are considered an important element of preanesthetic evaluation to determine the fitness for anesthesia and surgery. During past few decades this practice has been a subject of close scrutiny due to low yield and high aggregate cost. Performing routine screening tests in patients who are otherwise healthy is invariably of little value in detecting diseases and in changing the anesthetic management or outcome. Thorough history and investig...

2011-01-01

205

Laboratory astrophysics: Investigation of planetary and astrophysical maser emission  

Science.gov (United States)

This paper describes a model for cyclotron maser emission applicable to planetary auroral radio emission, the stars UV Ceti and CU Virginus, blazar jets and astrophysical shocks. These emissions may be attributed to energetic electrons moving into convergent magnetic fields that are typically found in association with dipole like planetary magnetospheres or shocks. It is found that magnetic compression leads to the formation of a velocity distribution having a horseshoe shape as a result of conservation of the electron magnetic moment. Under certain plasma conditions where the local electron plasma frequency ? pe is much less than the cyclotron frequency ? ce the distribution is found to be unstable to maser type radiation emission. We have established a laboratory-based facility that has verified many of the details of our original theoretical description and agrees well with numerical simulations. The experiment has demonstrated that the horseshoe distribution produces cyclotron emission at a frequency just below the local electron cyclotron frequency, with polarisation close to X-mode and propagating nearly perpendicularly to the electron beam motion. We discuss recent developments in the theory and simulation of the instability including addressing radiation escape problems, and relate these to the laboratory, space, and astrophysical observations. The experiments showed strong narrow band EM emissions at frequencies just below the cold-plasma cyclotron frequency as predicted by the theory. Measurements of the conversion efficiency, mode and spectral content were in close agreement with the predictions of numerical simulations undertaken using a particle-in-cell code and also with satellite observations confirming the horseshoe maser as an important emission mechanism in geophysical/astrophysical plasmas. In each case we address how the radiation can escape the plasma without suffering strong absorption at the second harmonic layer.

Bingham, R.; Speirs, D. C.; Kellett, B. J.; Vorgul, I.; McConville, S. L.; Cairns, R. A.; Cross, A. W.; Phelps, A. D. R.; Ronald, K.

206

Theoretical and Experimental Investigations of DNA Open States  

CERN Document Server

This research is a review and assay of literature data on the properties of DNA open states. The states result from large fluctuations of a duplex and have a great influence on a wide range of biochemical processes, including electric charge transfer in DNA. A comparative analysis of kinetic and thermodynamic experimental data on DNA open states has been performed for a wide temperature range. Apparent contradictions between the data of different experiments have been explained. Based on differences in thermodynamic properties and other characteristics three different types of DNA open states have been identified; a modern definition of the term "open state" has been given. A brief review of simple mathematical models of DNA has been presented; in most of the models the state of every base pair is defined by one or two variables. The central problems of investigation of heterogeneous DNA within the approaches of the level considered are examined. The roles of every model group in experimental data interpretat...

Shigaev, A S; Lakhno, V D

2014-01-01

207

Experimental and analytical investigation of the fuel rack float system  

International Nuclear Information System (INIS)

The demands for greater reliability and optimization in the design of seismic resisting nuclear components have created a need for better methods to predict the dynamic responses of the fuel storage rack assemblies to a prescribed earthquake motion. Recently it is proposed to reduce floor loading and therefore increase fuel storage capabilities of most existing spent fuel storage pools by displacing the pool water with floats. The main thrust of this paper is to present experimental and analytical investigations of the dynamic response of the fuel rack-float system subjected to seismic excitation. In the analytical model, coulomb friction and hydrodynamic mass effects are included. Experimental and analytical results indicated that the addition of the float to the fuel rack will reduce seismic load by altering hydrodynamic forces

1983-06-19

208

Further laboratory and theoretical investigations of ammonium dinitramide  

Energy Technology Data Exchange (ETDEWEB)

Hydrogen and deuterated ammonium dinitramide have been vaporized under high vacuum and the IR matrix isolation spectra of the decomposition products obtained. Tentative vibration assignments have been made for HN(NO{sub 2}){sub 2} and DN(NO{sub 2}){sub 2} assuming a symmetrical non-planar structure in which the H or D is bonded to the central nitrogen atom. Other structures are also possible. Ab initio calculations have been made for the various structural isomers of hydrogen dinitramide. Vibration frequencies calculated for the hydrogenated and deuterated species are compared with the experimental values with the object of identifying the molecules` structure. (authors) 3 refs.

Tulis, A.J.; Snelson, A. [IIT Research Institut, Chicago (United States); Heberlein, C.; Patel, D.L. [U.S. Army Cecom RD et E Center, NVESD (United States)

1996-12-31

209

Students' Assessment of Interactive Distance Experimentation in Nuclear Reactor Physics Laboratory Education  

Science.gov (United States)

Laboratory experiments develop students' skills in dealing with laboratory instruments and physical processes with the objective of reinforcing the understanding of the investigated subject. In nuclear engineering, where research reactors play a vital role in the practical education of students, the high cost and long construction time of…

Malkawi, Salaheddin; Al-Araidah, Omar

2013-01-01

210

Counter-Top Thermoacoustic Refrigerator- An Experimental Investigation  

International Nuclear Information System (INIS)

Thermoacoustic phenomenon is a new alternative refrigeration technology. Though design and fabrication is complex for getting the desired effect, it is environmentally friendly and successful system showed that it is relatively easy to run compared to the traditional vapor compression refrigeration system. Currently, theories supporting the thermoacoustic refrigeration systems are yet to be comprehensive to make them commercially viable. Theoretical, experimental, and numerical studies are being done to address the thermodynamics-acoustics interactions. In this study, experimental investigations were completed to test the feasibility of the practical use of a thermoacoustic refrigerator in its counter-top form for future specific application. The system was designed and fabricated based on linear acoustic theory. Acoustic power was given by a loud speaker and thermoacoustic effects were measured in terms of the cooling effects produced at resonanance. Investigations showed that discrepancies between designed and working resonance frequency exist. Thermoacoutic cooling improved at a certain frequency, achieved when the working frequency was varied away from the design frequency. A cooling effect of 4.8 K below the ambient temperature of 23.3 deg. C was obtained from the counter-top thermoacoustic system. This system uses no refrigerants and no compressor to generate the cooling effect, a potential to be further investigated for a practical system.

2010-06-28

211

Experimental and theoretical investigation of pulsed plasma thrusters  

Science.gov (United States)

An experimental and theoretical effort was carried out to investigate and explore various design modifications to improve pulsed plasma thruster (PPT) performance in the energy range between 5 and 60 J. Experimentally, a benchmark PPT was fabricated, and its performance evaluated and found to be comparable to previous flight type PPTs. A thermal management study to determine and elucidate energy loss mechanisms occurring in PPTs was conducted. It was determined that Teflon surface temperatures in excess of 370°K were attained during steady state thruster operation after the current pulse has ended contributing to the "late time ablation" of Teflon molecules. Also, radiation losses from the PPT structure accounted for approximately 50% of the thruster's stored energy. An inductively-driven plasma-actuated PPT was designed and fabricated to evaluate and investigate the effect of changing the discharge current waveform on PPT performance. A 1 muH inductor was used but resulted in reduced discharge current peaks and reduced Teflon ablation; this resulted in low thrust efficiency. In addition, the crowbar electrode placement contributed to the thrust degradation of the thruster since it resulted in a lateral JXB force that was not directed along the thrust axis. Coaxial inverse-pinch PPT configurations were designed, fabricated, and tested in an attempt to achieve efficient mass utilization. Axisymmetric discharge current operation was successfully achieved. Experimental and MACH2 predicted enclosed current contours agreed for 20 and 30 J thruster operation. Comparisons between the experimental and theoretically determined ablation rates indicated good agreement for 20 J but not for 30 J thruster operation. For 20 J, the temperature of the Teflon propellant surface never exceeded 6730K, thus indicating that no "late time ablation" due to Teflon molecule decomposition was occurring. For the 30 J thruster operation the MACH2 predicted ablation rate magnitude was only 40% of the experimentally measured value. Analysis of the temperature profile found that the temperature in the Teflon solid exceeded 673°K; this resulted in additional mass ablation after the current pulse has ended. To account for the difference between the experimental and theoretical ablation rates, it was found that Teflon decomposition occurs for Teflon temperatures above 705°K. Coaxial inverse-pinch PPT thrust efficiency of 5.3% was achieved at a specific impulse of 2420 s for 20 J thruster operation. This 150% improvement in specific impulse over the 20 J benchmark PPT operation is an indication of improved mass utilization.

Kamhawi, Hani

212

Experimental investigation of edge localised modes in JET  

International Nuclear Information System (INIS)

Edge Localised Modes (ELMs) in the JET tokamak have been studied experimentally, using density profile and fluctuation data from a multichannel reflectometer and temperature profile data from an ECE heterodyne radiometer. The following topics have been investigated: The radial extent and localisation of the density and temperature profile perturbations caused by the ELMs. Fluctuations in the density and magnetic field in connection with the ELMs. The correlation between the repetition frequency of the L-H transition ELMs, and the plasma edge temperature and density. Trajectories in n-T space prior to ELMs later in the H-mode. (au) (39 refs.)

1993-01-01

213

Experimental Investigations of Three-Body Systems at KVI  

Science.gov (United States)

Three-body systems have been studied in detail at KVI in the past few years. Two categories of reactions have been chosen to investigate these systems, namely elastic and break-up reactions in proton-deuteron scattering in which only hadrons are involved, and proton-deuteron capture reaction involving real and virtual photons in the final state. Some results from both types of reactions will be presented along with theoretical calculations showing that despite a relatively good understanding of these systems, there are still discrepancies between the experimental results and the theoretical calculations.

Kalantar-Nayestanaki, N.

2007-01-01

214

Heat transfer crisis on sintered porous surfaces – experimental investigations  

Directory of Open Access Journals (Sweden)

Full Text Available There were presented the results of theoretical analysis of boiling heat transfer on heating surfaces covered with thin-layered capillary porous structures. The paper discussed the results of experimental investigations into intralayer boiling crisis and accompanying phenomena. It was observed that the structural parameters of the porous covering affected the course of the process. Hysteresis phenomenon manifested itself when the heat flux initiating intralayer heat crisis was reached. The crisis mechanism hypotheses, the description of which was available in literature, were discussed.

Wojcik Tadeusz Michal

2012-04-01

215

Numerical and experimental investigation of a single ended radiant tube  

Energy Technology Data Exchange (ETDEWEB)

The Single Ended Radiant (SER) tube is an advanced type of the Natural-Gas Fired Radiant (NGFR) tubes which have been widely used in industrial heating processes. The present paper deals with the experimental investigations and numerical simulations of the SER tube with the objective of validating the turbulence models to which the final solutions have been found very sensitive. A RNG-based turbulence model is firstly validated against measurements in relaminarization, chemical reacting flows and then is applied to model the SER tube case. The performance of this RNG model is discussed and the agreement between the predictions and the measurements has been found satisfactory.

Mei, F.; Meunier, H.

1997-07-01

216

Experimental investigation of a photorefractive ring phase modulation amplifier  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present the experimental investigation of a photorefractive ring phase modulation amplifier, that is not resonant and that can work with distorted beams. We show that with this geometry an amplification by a factor 5 of a phase modulation signal is possible. We also show that this strong amplification is alleviated by the presence of losses in the ring. These losses lead to a real gain in signal to noise ratio of a factor 3, that nevertheless expresses that with such a system the photon no...

Delaye, Philippe; Frey, Laurent; Mugnier, Alain; Roosen, Ge?rald

1997-01-01

217

Experimental investigation of processes in primary circuit relief system  

International Nuclear Information System (INIS)

The protective condenser (direct contact condenser) is one of the basic components of the primary circuit relief system of WWER power plants. The steam flowing from the surge tank through relief valves into the subcooled water condensates in the protective condenser vessel. Two simple physical models were designed and constructed for investigation of bubbling through (contact condensation). An experimental program was performed with the aim of determining the distribution of temperatures in the axis of the steam jet and its vicinity, determining the velocity field of water into vicinity of steam jets, observing the geometrical shape of jets and their interaction and determining important values for mathematical model. (orig.)

1989-01-01

218

Experimental investigation of neutron emission mechanism for 252 Cf fission  

International Nuclear Information System (INIS)

The mechanism of prompt neutron emission in 252 Cf fission is investigated basing on the comparison of the measured spectra for neutron escape angles of 0 and 90 deg relative to the fission axis. It is revealed that neutron yield for the angle of 90 deg is 5.2 ± 2.1 % greater than the value predicted by the model of isotropy emission calculated on the base of experimental spectra for the angle of 0 deg. It is shown that this deviation amounts to 2.5 ± 1 % if being re-estimated for total neutron yield

1998-06-01

219

Experimental investigation of the permeability for unconsolidated porous media  

Energy Technology Data Exchange (ETDEWEB)

A device was constructed to investigate the permeability of unconsolidated media at low flow rate and small pressure drop. The stability and reliability of the device have been verified through repeated experiments on a given porous medium. The experimental investigation on the porous media demonstrated that the permeability-porosity relation is unique for a given medium. Experiments with the narrow screened sands show that conventional hydrodynamics theory and dimension analysis can not be applied satisfactorily in the study of the capillary porous media. For screened sand whose particle size ranges from 0.10mm to 0.45mm and size rate is 1:1.25, the permeability can be estimated from formula k = 4.89 x 10{sup {minus}4} d{sup 1.465} {phi}{sup 4.69} where k and d are limited in m{sup 2} and m, respectively.

Lei, S.Y.; Jia, L.Q.; Xia, C.M.; Zheng, G.Y.

1997-07-01

220

Experimental investigation and model development for a harmonic drive transmission  

International Nuclear Information System (INIS)

Harmonic drive transmissions (HDTs) are compact, low-backlash, high-ratio, high-resolution rotary motion transmissions. One application to benefit from these attributes is the revolute joint robot. Engineers at the Advanced Photon Source (APS) are investigating the use of this type of robot for the positioning of an x-ray detector; understanding the properties of the robot components is crucial to modeling positioner behavior. The robot bearing elements had been investigated previously, leaving the transmission as the missing component. While the benefits of HDTs are well known, the disadvantages, including fluctuating dissipation characteristics and nonlinear stiffness, are not understood as well. These characteristics can contribute uncontrolled dynamics to the overall robot performance. A dynamometer has been constructed at the APS to experimentally measure the HDT's response. Empirical torque and position data were recorded for multiple transmission load cases and input conditions. In turn, a computer model of the dynamometer HDT system was constructed to approximate the observed response.

2007-08-26

 
 
 
 
221

Sesame seed allergy: Clinical manifestations and laboratory investigations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background: Plant-origin foods are among the most important sources of food allergic reactions. An increase in the incidence of sesame seed allergy among children and adults has been reported in recent years. The aim of this preliminary study was to investigate the prevalence, importance and clinical manifestations of sesame allergy among Iranian patients.Methods: In a cross-sectional survey, 250 patients with suspected IgE-mediated food allergies completed a questionnaire and underwent skin ...

Fazlollahi MR.; Pourpak Z.; Yeganeh M.; Gh, Kardor; Kazemnejad A.; Movahedi M.; Gharagozlou M.; Farid Hosseini R.; Farhoudi A.

2007-01-01

222

Laboratory Investigation of Noise-Canceling Headphones Utilizing ``Mr. Blockhead''  

Science.gov (United States)

While I was co-teaching an introductory course in musical acoustics a few years ago, our class investigated several pieces of equipment designed for audio purposes. One piece of such equipment was a pair of noise-canceling headphones. Our students were curious as to how these devices were in eliminating background noise and whether they indeed block low-frequency sounds as advertised.

Koser, John

2013-09-01

223

Laboratory investigations on the low pathogenic potential of Plesiomonas shigelloides.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The pathogenic properties of 16 Plesiomonas shigelloides strains recovered from humans with extraintestinal and intestinal illnesses, infected animals, and environmental sources were investigated. Most strains possessed a high cell charge and low surface hydrophobicity analogous to those of Shigella spp.; additionally, serogroup O:17 strains reacted with Shigella group D antisera. However, unlike the shigellae, P. shigelloides strains did not universally bind Congo red, were noninvasive in HE...

Abbott, S. L.; Kokka, R. P.; Janda, J. M.

1991-01-01

224

Analytical and experimental investigation of flutter suppression by piezoelectric actuation  

Science.gov (United States)

The objective of this research was to analytically and experimentally study the capabilities of piezoelectric plate actuators for suppressing flutter. Piezoelectric materials are characterized by their ability to produce voltage when subjected to a mechanical strain. The converse piezoelectric effect can be utilized to actuate a structure by applying a voltage. For this investigation, a two-degree-of-freedom wind tunnel model was designed, analyzed, and tested. The model consisted of a rigid wing and a flexible mount system that permitted a translational and a rotational degree of freedom. The model was designed such that flutter was encountered within the testing envelope of the wind tunnel. Actuators made of piezoelectric material were affixed to leaf springs of the mount system. Command signals, applied to the piezoelectric actuators, exerted control over the damping and stiffness properties. A mathematical aeroservoelastic model was constructed by using finite element methods, laminated plate theory, and aeroelastic analysis tools. Plant characteristics were determined from this model and verified by open loop experimental tests. A flutter suppression control law was designed and implemented on a digital control computer. Closed loop flutter testing was conducted. The experimental results represent the first time that adaptive materials have been used to actively suppress flutter. They demonstrate that small, carefully placed actuating plates can be used effectively to control aeroelastic response.

Heeg, Jennifer

1993-01-01

225

Computational and Experimental Investigations of Boundary Layer Tripping  

Directory of Open Access Journals (Sweden)

Full Text Available Supersonic flow over a tapered body of revolution has been investigated both experimentally and numerically. The experimental study consisted of a series of wind tunnel tests on an ogive-cylinder body. Static pressure distributions on the body surfaces at several longitudinal cross sections, as well as the boundary layer profiles at various angles of attack have been measured. Further, the flow around the model was visualized using Schlieren technique. Tests with a natural development of the boundary layer and with tripping were also carried out. All tests were conducted in the trisonic wind tunnel of Qadr Research Center. Our results show that artificial boundary layer tripping has minor effect on the static surface pressure distribution (depending on its diameter and installation location, while the changes in total pressure around the body were significant. Tripping the boundary layer increased its thickness, changed its profile particularly near the body surface. Two oblique shock waves were formed in the front and behind the trip wire. In this study, using multi-block grid, the thin layer Navier-Stokes (TLNS equations were solved around the above models. Also patched method was used near the interfaces. Good agreements were achieved when the numerical results were compared with the corresponding experimental data.

M.R Heidari

2010-01-01

226

Laboratory investigations on granulation ability of brown coal dust  

Energy Technology Data Exchange (ETDEWEB)

This article presents detailed results of laboratory granulation experiments employing pulverized soft brown coal, carried out with the aim of reducing the strong flow behavior of coal dust. The granulated coal dust (produced by compacting dust on a roller press to sheets of 4 mm thickness and crumbling of the sheet) was briquetted on a briquetting press and then coked in a brown coal high temperature coking furnace. Three variants of granulation were tried; granulation results and the influence of the granulation method on quality of produced coking briquets and coke, in particular compression strength, are evaluated. The first variant was granulating dry brown coal dust with the addition of up to 25% comminuted brown coal in a grain size of 1/0 mm and with 11% moisture content. This measure substantially reduced the flow behavior of the dust but also lowered the compression strength of the resulting coke to some degree (in one test from 35.2 to 34.6 MPa and in another from 40.7 to 32.8 MPa). The second variant was granulating dust with a higher moisture content (25 to 30%) at a pressure of 15 MPa, followed by drying of the granules to 8-11% moisture content. This method largely eliminated coal dust flow and did not reduce coke strength: coke with strength up to 44.4 MPa was produced. The third method consisted of granulating the dust in a steam atmosphere with a coal/steam relation of 150:1. This method only lowered the dust flow to some extent; the compression strength of the resulting coke was lowered after longer steaming intervals. Conclusive results of the methods will require testing on an industrial scale. (10 refs.)

Krug H.; Naundorf, W.; Trommer, D.

1982-01-01

227

Experimental investigation of helical structures in swirling flows  

International Nuclear Information System (INIS)

Highlights: ? A swirl tube with variable exit orifices was experimentally investigated. ? Magnetic resonance velocimetry was applied to measure 3D3C velocity fields. ? One major observation is the occurrence of a three-layered flow structure. ? A new velocity zone of swirl flows was discovered: A fast jet in the core of the flow. ? Excentrical exit orifice trigger the development of helical structures in the flow. - Abstract: In this investigation the flow in a generic swirl tube with a tangential double-inlet swirl generator and variable exit orifices was experimentally investigated. Using magnetic resonance velocimetry (MRV) three-dimensional, three-component velocity fields were measured for two different Reynolds numbers: 10,000 and 15,000, and for three different exit orifices. The swirl generator had a fixed geometry producing an initial swirl number of 1.6 for all cases. One major observation is the occurrence of a three-layered flow structure. An annular main flow was surrounded by a recirculation zone, as reported in previous literature. However, this recirculation zone – also of an annular shape – exhibited a third layer inside: a thin, high speed jet in the center of the tube with the same flow direction as the main flow. Therefore, the conventional classification of swirling flows into ring and recirculation zone, has to be extended by a core zone. This three-layered flow structure develops independently of the exit configuration. Helical structures were observed in the near-wall region for all cases investigated. Applying an eccentric exit orifice results in the occurrence of strong stationary helical structures not only in the near-wall region but also in the center of the tube. The results, deviating significantly from previous results in the literature, underline the need for more detailed research on the topic of cyclone type flows.

2012-10-01

228

Experimental and theoretical investigation of high gradient acceleration  

Energy Technology Data Exchange (ETDEWEB)

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-FG0291ER-40648. Experimental and Theoretical Investigations of High Gradient Acceleration.'' This grant supports three research tasks: Task A consists of the design and fabrication of a 17GHz of photocathode gun, Task B supports the testing of high gradient acceleration using a 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tasks and on critical physics issues for the development of high energy linear colliders. This report is organized as follows. The development of an rf gun design and research progress on the picosecond laser system is summarized in Sec. 2, the status of the studies of the LBL/Haimson high gradient structure, using a 50 MW free-electron laser is summarized in Sec. 3, and theoretical research progress is described in Sec. 4. Supporting material is contained in Appendices A-G.

Bekefi, G.; Chen, C.; Chen, S.; Danly, B.; Temkin, R.J.; Wurtele, J.S.

1992-02-01

229

Experimental and analytical investigation of liquid sheet breakup characteristics  

Energy Technology Data Exchange (ETDEWEB)

The main objective of this research is to study analytically and experimentally the liquid sheet breakup of a flat fan jet nozzle resulting from pressure-swirling. In this study the effects of nozzle shape and spray pressure on the liquid sheet characteristics were investigated for four nozzles with different exit widths (1.0, 1.5, 2.0 and 2.5 mm). The length of liquid sheet breakup, liquid sheet velocity and the size of formed droplets were measured by a digital high speed camera. The breakup characteristics of plane liquid sheets in atmosphere are analytically investigated by means of linear and nonlinear hydrodynamic instability analyses. The liquid sheet breakup process was studied for initial sinuous and also varicose modes of disturbance. The results presented the effect of the nozzle width and the spray pressure on the breakup length and also on the size of the formed droplets. Comparing the experimental results with the theoretical ones for all the four types of nozzles, gives a good agreement with difference ranges from 4% to 12%. Also, the comparison between the obtained results and the results due to others shows a good agreement with difference ranged from 5% to 16%. Empirical correlations have been deduced describing the relation between the liquid sheet breakup characteristics and affecting parameters; liquid sheet Reynolds number, Weber number and the nozzle width.

Negeed, El-Sayed R., E-mail: s.negeed@gmail.co [Reactors Dept., Nuclear Research Center, Atomic Energy Authority, P.O. Box 13759, Cairo (Egypt); Hidaka, S.; Kohno, M. [Department of Mechanical Engineering Science, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); Takata, Y., E-mail: takata@mech.kyushu-u.ac.j [Department of Mechanical Engineering Science, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan)

2011-02-15

230

Experimental investigation of turbulent mixing by Rayleigh-Taylor instability  

International Nuclear Information System (INIS)

A key feature of compressible turbulent mixing is the generation of vorticity via the ?px ?(1/?) term. This source of vorticity is also present in incompressible flows involving the mixing of fluids of different density, for example Rayleigh-Taylor unstable flows. This paper gives a summary of an experimental investigation of turbulent mixing at a plane boundary between two fluids, of densities ?_1, and ?_2. (?_1 > ?_2) due to Rayleigh-Taylor instability. The two fluids are near incompressible and mixing occurs when an approximately constant acceleration, g, is applied normal to the interface with direction from fluid 2 to fluid 1. Full details of the experimental programme are given in a set of three reports. Some of the earlier experiments are also described by Read. Previous experimental work and much of the theoretical research has concentrated on studying the growth of the instability from a single wavelength perturbation rather than turbulent mixing. Notable exceptions are published in the Russian literature. A related process, turbulent mixing induced by the passage of shock waves though an interface between fluids of different density is described by Andronov et al. The major purpose of the experiments described here was to study the evolution of the instability from small random perturbations where it is found that large and larger structures appear as time proceeds. A novel technique was used to provide the desired acceleration. The two fluids were enclosed in a rectangular tank, the lighter fluid 2 initially resting on top of the denser fluid 1. One or more rocket motors were then used to drive the tank vertically downwards. The aim of the experimental programme is to provide data for the calibration of a turbulence model used to predict mixing in real situations

1992-01-01

231

Clinical and laboratory investigation of experimentaly infected broilers with CIAV  

Directory of Open Access Journals (Sweden)

Full Text Available Chicken infectious anemia (CIA is widespread viral disease in countries with the intensive poultry industry. In susceptible birds CIAV causes anemia subcutaneous and intramuscular hemorrhages, lymphoid tissue atrophy immunosuppression, cachexia and increased mortality. Protection of progeny relies not only on age resistance but also on maternally delivered antibodies (Mabs so possessing the information on level and persistence of Mabs is of great significance. In our study experimental infection with CIAV was performed on one and seven days old broiler chickens from naturally infected parent flock during the rearing period. In infected birds, clinical signs hematological findings and humoral immune response were examined. After euthanasia, we looked for specific pathomorphological and histopathological changes that indicate the presence of CIAV infection. In all one and seven days old chickens maternally derived antibodies were established. No clinical signs of CIA were observed, hematological findings showed no deviation from referent values, and there were no specific pathomorphological and histopathological changes at postmortem examination. According to previous knowledge, only serological negative flock if infected in time of laying represent risk for vertical transmission to progeny where typical disease with mortality will appear. The absence of Mabs in one day old chickens is critical point in break of disease. Typical clinical picture in day old chickens rises only when vertical transmission occurs.

Kapetanov Miloš C.

2004-01-01

232

A review of geophysical investigations at the site of Chalk River Nuclear Laboratories, Ontario  

International Nuclear Information System (INIS)

The site of the Chalk River Nuclear Laboratories was one of the first research areas located on crystalline rocks to be extensively investigated under the Canadian Nuclear Fuel Waste Management Program. A large contribution to meeting the geoscientific objectives of the program has been made using a suite of geophysical techniques. Many of them are standard, though sometimes modified in terms of instrumentation and/or experimental and/or analytical procedures, to meet the particular needs of the waste management program. Relatively new techniques have also been employed. Much of the early evaluation and development of the various techniques took place at the Chalk River site. Standard methods such as gravity, magnetics and seismic sounding have been used to investigate bedrock structure, and the seismic method has also been used to estimate overburden thickness. Standard geophysical borehole logging has been used to obtain in situ estimates of physical properties, to locate fracture zones and to make hole to hole correlations that have helped define local structure. Several standard electrical (e.g. resitivity) and electromagnetic (e.g. VLF-EM) techniques have proven successful in identifying water-filled fractures and faults. Relatively new techniques introduced into the geophysics at Chalk River were: ground probing radar; to investigate overburden; borehole TV and acoustic televiewer and VLF-EM, to locate fractures; studies of seismic tube-waves, well tides and temperature logs, to investigate fracture location and permeability. Most of these methods have been successful and are now routinely employed at other research sites

1988-01-01

233

LABEXNET: un Laboratorio de Economía Experimental en Internet. [LABEXNET: Internet-based laboratory for experimental Economics  

Directory of Open Access Journals (Sweden)

Full Text Available Experimental Economists have designed over the years a wide range of scientific experiments that can be usefully employed nowadays as teaching aids. The interactive and participatory nature of such experiments serves as a motivation to students, stimulates their own thinking, and enhances their insights into the forces that drive economic markets: the aggregate interactions of economic agents within a market institution. Economic classroom games have been recognised as useful teaching tools for decades, and they have often produced surprising results and better understanding of market dynamics and institutions. Nowadays the new information technologies can be brought into play to conduct and analyse experimental games in unprecedented ways: using Internet-based tools, the design, execution and analysis of classroom games can be made considerably easier than traditionally. In this paper we introduce LABEXNET, a program designed to conduct Internet-based economic classroom games. LABEXNET is freely available to the academic community.. La Economía Experimental ha desarrollado diferentes experimentos que pueden ser aprovechados como una actividad docente en la enseñanza de la Economía. Su naturaleza activa y participativa motiva a los alumnos y estimula la reflexión y la mejor comprensión de algunos fenómenos económicos como el funcionamiento de los mercados, donde los resultados individuales dependen del conjunto de las decisiones de los agentes y de sus interacciones. Los experimentos económicos tienen ya una larga tradición, y han proporcionado resultados espectaculares y conclusiones ampliamente admitidas sobre la dinámica de mercados y el efecto de las instituciones económicas. Las nuevas tecnologías facilitan la realización y el análisis de estos experimentos. En este artículo presentamos LABEXNET, un programa informático para la realización de experimentos económicos por Internet puesto a libre disposición de la comunidad académica..

Galán Ordax, José Manuel

2007-06-01

234

Subsurface investigation of the Energy Systems Research Laboratory site at Oak Ridge National Laboratory  

International Nuclear Information System (INIS)

Subsurface soil from the site of the proposed Energy Systems Research Laboratory was examined to determine radioactive concentration levels. This study was undertaken because the proposed site is in close proximity to the former Solid Waste Storage Area-2. A total of 25 cores were taken, ranging in depth from 4 to 9 feet, and the soil samples were analyzed for gamma-, beta-, and alpha-emitting isotopes. Water taken from 13 of the core holes was analyzed to determine tritium, gross beta, and gross alpha levels. None of the samples analyzed were found to be significantly higher than background samples collected throughout eastern and central Tennessee. No special health physics precautions are expected to be needed for the excavation at the site, other than using the excavated soil as backfill at burial sites on the reservation

1977-01-01

235

Laboratory and Theoretical Investigations on Mechanical Behavior of PLFG Mixture  

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Full Text Available Phosphogypsum-lime-flyash-gravel Mixture (PLFG is usually used to strengthen road foundation of geotechnical engineering. It is important to correctly understand its mechanical behavior before corresponding design. In this present paper, compaction test, one-dimensional compression test and dry-shrinkage test were conducted to determine optimum mixture ration of PLFG. compression test on PLFG with optimum ration was carried out in order to investigate its stress-strain curve. Experiment data show that PLFG is with high bearing capacity and good stiffness. A new composite-exponent model was established, which is available for both hardening and softening type strain-stress curves of PLFG. Mathematical behavior of the presented model is far better than others to describe PLFG’s structural property. Finally, comparison between PLFG tested data and new model simulation was performed and good agreements have been found. This research is helpful for engineering sustainable utilization of to bring economy and to reduce environmental pollution.

Wang Wei

2013-01-01

236

Laboratory scale investigation of uranium melting and casting  

Energy Technology Data Exchange (ETDEWEB)

In this work, melting and casting experiments were undertaken to produce cast U rods of good quality, using U derbies produced locally. The effect of various melting and casting parameters on the quality of the U rods produced were investigated. These parameters were: melting temperature, holding time at that temperature, and cast rod diameter. The melting temperatures used were: 1200, 1300 and 1400/sup 0/C for holding periods ranging from 10-30 min. Rods of diameter 1 and 2 cm were cast and the length was 5 cm in all cases. Radiographic, X-ray diffraction, metallographic, density and hardness techniques were used for examination of the rods and as well as identification of inclusions. Casting was done in a vacuum resistance furnace using graphite crucibles and moulds coated with magnesia to minimize carbon pick up. Rods of 2 cm diameter melted at 1200/sup 0/C and cast with holding time 10 min. gave lowest inclusion content and the highest density (18.85 g/cc). These conditions also gave the lowest hardness (VHN 236) which is the closest to that of the cast pure U metal (VHN 220).

Abu Zahra, A.A.; Ghoneim, M.M.; Hammad, F.H. (Dept. of Nuclear Metallurgy, Nuclear Research Centre, A.E.A., Cairo (Egypt))

1980-01-01

237

Experimental investigations of silicon tetrafluoride decomposition in ECR discharge plasma  

Science.gov (United States)

The results of first experiments on the investigation of plasma of electron cyclotron resonance (ECR) discharge, sustained by CW radiation of technological gyrotron with frequency 24 GHz are considered. The parameters of nitrogen plasma of ECR discharge in magnetic field up to 1 T were investigated by Langmuir probe in the pressure range 10-4-10-2 mbar under different values of microwave power. Depending on gas pressure and power of microwave radiation, the typical temperature and density of electrons could attain values of 1-5 eV and 1011-1012 cm-3, respectively. The prospects for using of ECR discharge for plasma chemical decomposition of silicon tetrafluoride (SiF4) have been experimentally demonstrated. Plasma was created from SiF4 and hydrogen (H2) gas mixture and heated by microwave radiation in ECR conditions. Using the method of mass-spectrometry analysis of the gas at the outlet from the reactor and the weighting method, the content of the resultants of SiF4 decomposition as a function of process parameters was investigated. It was shown that SiF4 decomposition degree strongly depends on the microwave power, gas pressure in the reactor, gas flow rates, and can attain the value of 50%. The possible applications of PECVD method based on ECR discharge for production of isotopically pure elements with high deposition rate are discussed.

Vodopyanov, A. V.; Golubev, S. V.; Mansfeld, D. A.; Sennikov, P. G.; Drozdov, Yu. N.

2011-06-01

238

EXPERIMENTAL INVESTIGATION ON HIGH PERFORMANCE CONCRETE USING SILICAFUME AND FLYASH  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this experimental investigation is to study the behaviour of High Performance Concrete (HPC. In this investigation HPC was manufactured by usual ingredients such as cement, fine aggregate, coarse aggregate, water and mineral admixtures such as Silica Fume (SF and Fly ash at various replacement levels and with Super Plasticizer. The water binder ratio (w/b adopted is 0.30. The concrete used in this investigation was proportioned to target a mean strength of 60 MPa. Specimens such as cubes, cylinders and prism beams were cast and tested for various mixes viz. Seven mixes M1 to M7 are cast with 0%, 5%, 7.5% and 10% replacement of SF and another set of specimens with 0%, 5%, 7.5% and 10% replacement of SF along with 10% constant replacement of Fly ash to study the mechanical properties such as compressive strength, split tensile strength and flexural strength at different ages of concrete such as 3, 7, 28, 56 and 90 days. The result shows that the optimum replacement of silica fume is 7.5%. Totally The specimens were tested in 1000 kN loading frame at 28 days. The results were tabulated.

Kannan Kannan

2012-09-01

239

Experimental investigations of silicon tetrafluoride decomposition in ECR discharge plasma  

Energy Technology Data Exchange (ETDEWEB)

The results of first experiments on the investigation of plasma of electron cyclotron resonance (ECR) discharge, sustained by CW radiation of technological gyrotron with frequency 24 GHz are considered. The parameters of nitrogen plasma of ECR discharge in magnetic field up to 1 T were investigated by Langmuir probe in the pressure range 10{sup -4}-10{sup -2} mbar under different values of microwave power. Depending on gas pressure and power of microwave radiation, the typical temperature and density of electrons could attain values of 1-5 eV and 10{sup 11}-10{sup 12} cm{sup -3}, respectively. The prospects for using of ECR discharge for plasma chemical decomposition of silicon tetrafluoride (SiF{sub 4}) have been experimentally demonstrated. Plasma was created from SiF{sub 4} and hydrogen (H{sub 2}) gas mixture and heated by microwave radiation in ECR conditions. Using the method of mass-spectrometry analysis of the gas at the outlet from the reactor and the weighting method, the content of the resultants of SiF{sub 4} decomposition as a function of process parameters was investigated. It was shown that SiF{sub 4} decomposition degree strongly depends on the microwave power, gas pressure in the reactor, gas flow rates, and can attain the value of 50%. The possible applications of PECVD method based on ECR discharge for production of isotopically pure elements with high deposition rate are discussed.

Vodopyanov, A. V.; Golubev, S. V.; Mansfeld, D. A.; Sennikov, P. G. [Institute of Applied Physics Russian Academy of Sciences, Uljanova st. 46, Nizhny Novgorod 603950 (Russian Federation); Drozdov, Yu. N. [Institute for Physics of Microstructures Russian Academy of Sciences, GSP-105, Nizhny Novgorod 603950 (Russian Federation)

2011-06-15

240

Experimental Investigation of Ice Phase Change Material Heat Exchangers  

Science.gov (United States)

Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.

Leimkuehler, Thomas O.; Stephan, Ryan A.

2012-01-01

 
 
 
 
241

Experimental investigation of the Richtmyer-Meshkov instability.  

Energy Technology Data Exchange (ETDEWEB)

The Richtmyer-Meshkov instability (RMI) is experimentally investigated using several different initial conditions and with a range of diagnostics. First, a broadband initial condition is created using a shear layer between helium+acetone and argon. The post-shocked turbulent mixing is investigated using planar laser induced fluorescence (PLIF). The signature of turbulent mixing is present in the appearance of an inertial range in the mole fraction energy spectrum and the isotropy of the late-time dissipation structures. The distribution of the mole fraction values does not appear to transition to a homogeneous mixture, and it is possible that this effect may be slow to develop for the RMI. Second, the influence of the RMI on the kinetic energy spectrum is investigated using particle image velocimetry (PIV). The influence of the perturbation is visible relatively far from the interface when compared to the energy spectrum of an initially flat interface. Closer to the perturbation, an increase in the energy spectrum with time is observed and is possibly due to a cascade of energy from the large length scales of the perturbation. Finally, the single mode perturbation growth rate is measured after reshock using a new high speed imaging technique. This technique produced highly time-resolved interface position measurements. Simultaneous measurements at the spike and bubble location are used to compute a perturbation growth rate history. The growth rates from several experiments are compared to a new reshock growth rate model.

Weber, Christopher R. (University of Wisconsin-Madison, Madison, WI)

2011-09-01

242

Sesame seed allergy: Clinical manifestations and laboratory investigations  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Plant-origin foods are among the most important sources of food allergic reactions. An increase in the incidence of sesame seed allergy among children and adults has been reported in recent years. The aim of this preliminary study was to investigate the prevalence, importance and clinical manifestations of sesame allergy among Iranian patients.Methods: In a cross-sectional survey, 250 patients with suspected IgE-mediated food allergies completed a questionnaire and underwent skin prick tests with sesame extract as well as cross-reacting foods (walnut, soya and peanut. Total IgE and sesame-specific IgE levels were measured. Patients with positive skin test reactions and/or IgE specific for sesame without clinical symptoms were considered sensitive to sesame. The patients who also had clinical symptoms with sesame consumption were diagnosed as allergic to sesame.Results: Of the 250 patients enrolled in this study, 129 were male and 121 female, with a mean age of 11.7 years. The most common food allergens were cow's milk, egg, curry, tomato and sesame. Sesame sensitivity was found in 35 patients (14.1%. Only five patients (2% had sesame allergy. Sesame-sensitive patients had a significantly higher frequency of positive prick test to cross-reacting foods when compared to non-sensitized patients (p=0.00. The type of symptom was independent of gender and age of the patients, but urticaria and dermatitis-eczema were significantly more frequent in sensitized patients (p=0.008.Conclusions: This is the first study addressing the prevalence of sesame seed allergy in Iranian population. We found sesame to be a common and important cause of food allergy. The panel of foods recommended for use in diagnostic allergy tests should be adjusted.

Fazlollahi MR.

2007-10-01

243

Geophysical investigation: New Production Reactor Complex, Idaho National Engineering Laboratory  

Energy Technology Data Exchange (ETDEWEB)

Seismic crosshole and downhole velocity measurements were performed for two borehole arrays approximately 300 feet deep in conjunction with verticality measurements and geophysical logging of borehole WO-2 (to a depth of 4,960 feet) at the NPR site of the INEL. Past studies show that the site area is covered by a thin layer of soil which overlies numerous basalt flows interrupted by sandy and clayey interbeds. Compressional and shear wave velocities computed for these arrays revealed low velocity zones at the following elevation ranges for crosshole array No. 1: 4,893 feet to 4,873 feet (basalt rubble zone) and 4,705 feet to 4,686 feet (sediment interbed). Corresponding elevation ranges for crosshole array No. 2 include: 4,830 feet to 4,815 feet (sediment interbed), 4,785 feet to 4,765 feet (highly vesicular and fractured basalt), 4,715 feet to 4,705 feet (basalt rubble zone), and 4,672 feet to 4,667 feet (sediment interbed). In general, crosshole velocity data correlated between arrays with velocity differences possibly explained by localized lithologic changes. Due to scatter in the downhole velocity data, only velocity averages were computed. However, these downhole velocities correlated to the approximate mean crosshole velocity values and therefore independent confirmed the crosshole data. Geophysical logging of well WO-2 included natural gamma, neutron, and compensated density logs to a depth of 4,960 feet at which a viscous borehole fluid inhibited further investigation. Second runs of small sections of these logs were repeated satisfactorily for confirmation of certain anomalous areas.

Filipkowski, F.; Blackey, M.; Davies, D.; Levine, E.N.; Murphy, V. [Weston Geophysical Corp., Westboro, MA (US)

1991-12-01

244

Experimental investigations in turbulent buoyant jets of sodium  

International Nuclear Information System (INIS)

Axisymmetric, turbulent buoyant jets are investigated in the sodium test section TEFLU. The character of the flow is divided into three regimes depending on the densimetric Froude number: the pure jet, the buoyant jet in the transition regime and the pure plume. By means of a temperature compensated Miniature Permanentmagnet Flowmeter Probe the mean velocity, mean temperature and intensity of temperature fluctuations are measured simultaneously at axial distances between 3 and 40 initial jet diameters from the orifice. The functional principle of the Miniature Permanentmagnet Flowmeter Probe which allows velocity measurements to be made in the presence of a temperature gradient is described in detail. For all three regimes both the decay laws of the quantities measured along the axis of the containment pipe and the radial profiles are indicated and discussed. With the help of the radial profiles of the mean quantities the axial development of the half-width radii and the axial development of the momentum, buoyancy and volume fluxes are calculated. In addition, the time history of the temperature fluctuations is recorded at several radial positions. The data are analysed according to characteristic values of statistical signal analysis such as minimum value, maximum value, skewness, flatness and according to characteristic functions such as probability density function, autopower spectrum density and autocorrelation function. The experimental results for the axisymmetric, turbulent buoyant jets of sodium are compared with experimental results from the literature and with fluids of molecular Prandtl numbers greater than or equal to 0.7. The basic differences betwen the experimental results obtained for water and for sodium are outlined. Statements are formulated which allow thermo- and fluiddynamic diffusion processes to be transferred from water to sodium. (orig.)

1993-01-01

245

Experimental investigations on vessel-hole ablation during severe accidents  

Energy Technology Data Exchange (ETDEWEB)

This report presents experimental results, and subsequent analyses, of scaled reactor pressure vessel (RPV) failure site ablation tests conducted at the Royal Institute of Technology, Division of Nuclear Power Safety (RIT/NPS). The goal of the test program is to reduce the uncertainty level associated with the phase-change-ablation process, and, thus, improve the characterization of the melt discharge loading on the containment. In a series of moderate temperature experiments, the corium melt is simulated by the binary oxide CaO-B{sub 2}O{sub 3} or the binary eutectic and non-eutectic salts NaNO{sub 3}-KNO{sub 3}, while the RPV head steel is represented by a Pb, Sn or metal alloys plate. A complementary set of experiments was conducted at lower temperatures, using water as melt and salted ice as plate material. These experiments scale well to the postulated prototypical conditions. The multidimensional code HAMISA, developed at RIT/NPS, is employed to analyze the experiments with good pre- and post-test predictions. The effects of melt viscosity and crust surface roughness, along with failure site entrance and exit frictional losses on the ablation characteristics are investigated. Theoretical concept was proposed to describe physical mechanisms which govern the vessel-hole ablation process during core melt discharge from RPV. Experimental data obtained from hole ablation tests and separate-effect tests performed at RIT/NPS were used to validate component physical models of the HAMISA code. It is believed that the hole ablation phenomenology is quite well understood. Detailed description of experiments and experimental data, as well as results of analyses are provided in the appendixes. 40 refs, 51 figs, 13 tabs.

Sehgal, B.R.; Dinh, T.N.; Green, J.A.; Paladino, D. [Royal Inst. of Tech., Stockholm (Sweden). Div. of Nuclear Power Safety

1997-12-01

246

Experimental Investigation of Turbulent Flow in Transition Duct  

Directory of Open Access Journals (Sweden)

Full Text Available An experimental study was conducted to investigate turbulent flow through from rectangular cross-sectional area to rectangular transition duct. Three kinds of channels with different length, side angle and geometrical dimensions were designed and then flow characteristic of them were all tested. The transition duct have different inlet and outlet cross-sectional areas, outlet section is double than inlet sectional area. Measurements were made at several station along the channel and at various flow-rates, Reynolds numbers ranging from 2.105 to 6.105, in which the two–dimensional mean, local velocity and pressure were measured at the x/l = 0.20, 0.40, 0.60, 0.80, 1.00 ratio, inlet by using hot wire anemometer. Based on experimental results, different flow characteristics were obtained. According to mean and local velocity and pressure drop values, each section point of the transition duct showed various values. Friction coefficient was lowered with increasing pipe length and increasing Reynolds number. Cross flows was shown in the short pipe along length at the low Reynolds.

Hasan GÜL

2012-12-01

247

Experimental and numerical investigation of hydrogen gas auto-ignition  

Energy Technology Data Exchange (ETDEWEB)

This paper describes hydrogen self-ignition as a result of the formation of a shock wave in front of a high-pressure hydrogen gas propagating in the tube and in the semi-confined space, for which the numerical and experimental investigation was done. An increase in the temperature behind the shock wave leads to the ignition on the contact surface of the mixture of combustible gas with air. The required condition of combustible self-ignition is to maintain the high temperature in the mixture for a time long enough for inflammation to take place. Experimental technique was based on a high-pressure chamber inflating with hydrogen, burst disk failure and pressurized hydrogen discharge into tube of round or rectangular cross section filled with air. Two numerical models involving the gas-dynamic transport of a viscous gas, the detailed kinetics of hydrogen oxidation, turbulence model, and heat exchange were used for calculations of the hydrogen self-ignition both in semi-confined space and a tube. (author)

Golub, V.V.; Baklanov, D.I.; Bazhenova, T.V.; Golovastov, S.V.; Ivanov, M.F.; Laskin, I.N.; Semin, N.V.; Volodin, V.V. [Department of Physical Gasdynamics, Joint Institute for High Temperatures RAS, Izhorskaya st. 13, bld. 2, 125412 Moscow (Russian Federation)

2009-07-15

248

Surface plasmon resonance of Ag organosols: Experimental and theoretical investigations  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this paper is to investigate and compare the changes in surface plasmon resonance (SPR of silver (Ag hydrosol and organosols obtained by experimental and theoretical approaches. Silver nanoparticles (Ag NPs of 5 ± 1.5 nm in diameter were prepared in water by reduction of silver nitrate with sodium borohydride. Nanoparticles were subsequently transferred into different organic solvents (chloroform, hexane, toluene, 1,2-dichlorobenzene using oleylamine as a transfer agent. These solvents were chosen because of the differences in their refractive indices. Using UV-Vis absorption spectrophotometry and transmission electron microscopy (TEM, we confirmed that there were no shape and size changes of the nanoparticles upon the transfer to the organic phase. The absorption spectra of the obtained Ag organosols showed only changes in the position of SPR band depending on dielectric property of the used solvent. To analyze these changes, absorption spectra were modelled using Mie theory for small spherical particles. The experimental and theoretical resonance values were compared with those predicted by Drude model and its limitations in the analysis of absorption behavior of Ag NPs in organic solvents were briefly discussed.

Vodnik Vesna

2012-01-01

249

Experimental investigation of reduced-mixing personal ventilation jets  

Energy Technology Data Exchange (ETDEWEB)

This paper presents an investigation of the design and performance characteristics of personalized ventilation (PV) systems that, in combination with general ventilation, deliver high quality air to the breathing zone (BZ) with no more clean air supply than indicated by ANSI/ASHRAE 62.1-2004, while satisfying acceptable ergonomic and aesthetic considerations. Under these conditions, the energy used for conditioning the clean air will not exceed that of a conventional ventilation system. We introduce a novel PV nozzle that achieves high BZ air quality with a small fraction of the clean air indicated by the ANSI/ASHRAE Standard. Tracer gas experimental results presented in this paper demonstrate the advantages of the novel nozzle relative to conventional PV nozzles. The results show that, at a PV clean air supply of only 2.4 l/s, the new nozzle achieves a BZ ventilation effectiveness close to 7 versus less than 2 for a conventional nozzle delivering the same amount of clean air. A companion paper presents a computational analysis of the same concept, validated against the experimental results of the present paper. (author)

Khalifa, H. Ezzat; Janos, Michael I.; Dannenhoffer, John F. III. [Syracuse University, Syracuse, NY (United States)

2009-08-15

250

Experimental investigations of the functional morphology of dragonfly wings  

Science.gov (United States)

Nowadays, the importance of identifying the flight mechanisms of the dragonfly, as an inspiration for designing flapping wing vehicles, is well known. An experimental approach to understanding the complexities of insect wings as organs of flight could provide significant outcomes for design purposes. In this paper, a comprehensive investigation is carried out on the morphological and microstructural features of dragonfly wings. Scanning electron microscopy (SEM) and tensile testing are used to experimentally verify the functional roles of different parts of the wings. A number of SEM images of the elements of the wings, such as the nodus, leading edge, trailing edge, and vein sections, which play dominant roles in strengthening the whole structure, are presented. The results from the tensile tests indicate that the nodus might be the critical region of the wing that is subjected to high tensile stresses. Considering the patterns of the longitudinal corrugations of the wings obtained in this paper, it can be supposed that they increase the load-bearing capacity, giving the wings an ability to tolerate dynamic loading conditions. In addition, it is suggested that the longitudinal veins, along with the leading and trailing edges, are structural mechanisms that further improve fatigue resistance by providing higher fracture toughness, preventing crack propagation, and allowing the wings to sustain a significant amount of damage without loss of strength.

Rajabi, H.; Darvizeh, A.

2013-08-01

251

Experimental investigation of pyrolysis process of woody biomass mixture  

Science.gov (United States)

This paper describes an experimental investigation of pyrolysis of woody biomass mixture. The mixture consists of oak, beech, fir, cherry, walnut and linden wood chips with equal mass fractions. During the experiment, the sample mass inside the reactor was 10 g with a particle diameter of 5-10 mm. The sample in the reactor was heated in the temperature range of 24-650°C. Average sample heating rates in the reactor were 21, 30 and 54 °C/min. The sample mass before, during and after pyrolysis was determined using a digital scale. Experimental results of the sample mass change indicate that the highest yield of pyrolytic gas was achieved at the temperature slightly above 650°C and ranged from 77 to 85%, while char yield ranged from 15 to 23%. Heating rate has significant influence on the pyrolytic gas and char yields. It was determined that higher pyrolysis temperatures and heating rates induce higher yields of pyrolytic gas, while the char mass reduces. Condensation of pyrolytic gas at the end of the pyrolysis process at 650°C produced 2.4-2.72 g of liquid phase. The results obtained represent a starting basis for determining material and heat balance of pyrolysis process as well as woody biomass pyrolysis equipment.

Kosani?, Tijana R.; ?erani?, Mirjana B.; ?uri?, Slavko N.; Grkovi?, Vojin R.; Miloti?, Milan M.; Brankov, Saša D.

2014-06-01

252

Experimental investigation of a two-phase nozzle flow  

International Nuclear Information System (INIS)

Stationary two-phase flow experiments with a convergent nozzle are performed. The experimental results are appropriate to validate advanced computer codes, which are applied to the blowdown-phase of a loss-of-coolant accident (LOCA). The steam-water experiments present a broad variety of initial conditions: the pressure varies between 2 and 13 MPa, the void fraction between 0 (subcooled) and about 80%, a great number of critical as well as subcritical experiments with different flow pattern is investigated. Additional air-water experiments serve for the separation of phase transition effects. The transient acceleration of the fluid in the LOCA-case is simulated by a local acceleration in the experiment. The layout of the nozzle and the applied measurement technique allow for a separate testing of blowdown-relevant, physical models and the determination of empirical model parameters, respectively. The measured quantities are essentially the mass flow rate, quality, axial pressure and temperature profiles as well as axial and radial density/void profiles obtained by a ?-ray absorption device. Moreover, impedance probes and a pitot probe are used. Observed phenomena like a flow contraction, radial pressure and void profiles as well as the appearance of two chocking locations are described, because their examination is rather instructive about the refinement of a program. The experimental facilities as well as the data of 36 characteristic experiments are documented. (orig.)

1980-01-01

253

Numerical and experimental investigation of the TRIP strain  

International Nuclear Information System (INIS)

In the first part a comprehensive experimental program is presented involving differential thermo-analyses (DTA) as well as dilatation tests under various non-proportional mechanical as well as thermal loading paths with the objective to measure the additional inelastic strain contribution due to transformation induced plasticity (TRIP). A maraging steel exhibiting complete martensitic transformation in a temperature interval ranging from around 150 oC down to about 70 oC is chosen as an appropriate testing material, since its comparatively low martensite start temperature (MS) facilitates measuring and precludes undesirable creep effects. A concept on how to isolate the TRIP strain contribution from the overall strain monitored by the multiaxial testing device is discussed. Particular attention is paid to the evolution of the martensite fraction during transformation and its dependence on the type and the magnitude of the applied mechanical load. The second part deals with the numerical simulation of the thermo-mechanical material behavior using an elastic predictor - radial return algorithm based on the underlying thermodynamic principles as the starting point. A user supplied subroutine has been developed that provides a commercial finite element solver with the proper material response to a given strain increment. The behavior of a three dimensional unit cell consisting of a regular array of cubic elements, each representing a single, arbitrarily oriented grain of a polycrystal is investigated. The good agreement of the numerical results with the experimental data backs the notion of a transformation related backstress is proposed. Refs. 3 (author)

2002-07-07

254

Experimental Investigation on the Viscosity of Nano fluids  

International Nuclear Information System (INIS)

In this study, the effect of adding SiO2 nanoparticles on the viscosity of base fluid is investigated experimentally. Base fluids are chosen among common heat transfer fluids such as ethylene glycol, transformer oil and water. In addition different volume percentages of ethylene glycol in water are used as ethylene glycol-water solution. In every base fluid different volume fractions of SiO2 nanoparticles is added. It is shown that the viscosity of solution enhance by adding nanoparticles. The effect of cooling and heating process on the viscosity of nano fluid is also discussed. The presented data show that as the temperature increases the viscosity of base fluid and nano fluid decrease. It is also revealed that there are very little differences between the viscosity of nano fluid in a specific temperature at cooling and heating cycles. According to the experimental results new correlations for predicting the viscosity of nano fluids is presented. These correlations relate the viscosity of nano fluid to the particle volume fraction and temperature.

2012-08-01

255

An experimental-differential investigation of cognitive complexity  

Directory of Open Access Journals (Sweden)

Full Text Available Cognitive complexity as defined by differential and experimental traditions was explored to investigate the theoretical advantage and utility of relational complexity (RC theory as a common framework for studying fluid cognitive functions. RC theory provides a domain general account of processing demand as a function of task complexity. In total, 142 participants completed two tasks in which RC was manipulated, and two tasks entailing manipulations of complexity derived from the differential psychology literature. A series of analyses indicated that, as expected, task manipulations influenced item difficulty. However, comparable changes in a psychometric index of complexity were not consistently observed. Active maintenance of information across multiple steps of the problem solving process, which entails strategic coordination of storage and processing that cannot be modelled under the RC framework was found to be an important component of cognitive complexity.

2009-12-01

256

Torsional Performance of Wind Turbine Blades : Part I: Experimental Investigation  

DEFF Research Database (Denmark)

The complete 3D static responses of two different eight meter long wind turbine blade sections were tested. To experimentally investigate the 3D response, an advanced 3D digital optical deformation measuring system (ARAMIS 2M and 4M) was applied in this work. This system measures the full-field displacements (ux, uy and uz) of the blade surface. A least squares algorithm was developed, which fits a plane through each deformed cross section, and defines a single set of displacements and rotations (three displacements and rotations) per cross section. This least squares algorithm was also used to accommodate problems with a flexible boundary condition by determining the displacements and rotations for a cross section near the boundary. These displacements and rotations are subtracted from all other cross sections along the blade and thereby making the blade section fully fixed at the chosen cross section near the boundary.

Berring, Peter; Branner, Kim

2007-01-01

257

A review of experimental investigations on blast resistance of structures  

International Nuclear Information System (INIS)

Investigations on blast resistance of structures received a lot of importance during and after the second world war. In recent years, this has assumed importance, in view of the rise in terrorist attack, accidents and sabotage. Development of computers and sophisticated instrumentation has led to more accurate mathematical modelling of the blast and response phenomena and more accurate validation of the mathematical model by experiments, bringing the analysis of this class of problems within the reach of the theoretical analyst. An attempt is made to review some recent trends in modelling, instrumentation and experimental procedures adopted by researchers working in the area of blast resistance of structures. (author). 32 refs., 8 figs., 1 tab

1994-05-01

258

Experimental investigation on critical heat flux in vertical tubes  

International Nuclear Information System (INIS)

An experimental study on critical heat flux of forced convection boiling in uniformly heated vertical tubes was performed in the KRISTA test facility at the Institute for Applied Thermo-and Fluid dynamics Karlsrule Research Center, using Freon-12 as the working fluid. Critical heat flux qc was measured in a 16 mm and a 2 mm diameter circular tubes. The effect of pressure, steam quality and mass velocity on CHF has been investigated. The results obtained were found to be essentially consistent in trend with the CHF data measured by other author. However, at lower pressure and mass velocity an anomalous phenomenon appeared: CHF decreased with decreasing inlet quality Xin in 2 mm diameter tube. The effect of pressure on CHF was complex. It was coupled with mass velocity and steam quality. At high mass velocity an inversion point was found out

1997-04-14

259

Investigation of tumor tissue alteration after experimental chemotherapy  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the present work was the study of tumor tissue alteration after new antineoplastic substance administration in comparison with widely investigated 5-fluorouracil. White rats bearing Plisse lymphosarcoma, sarcoma 45, Walker carcino-sarcoma, sarcoma 180 were used in the study. Pieces of tumor tissue were fixed in 10% neutral formaldehyde and processed using standard procedure. Histological slides were stained by hematoxylin and eosin method, van Gieson, Mc Manus, Feulgen and Picro-Mallori methods. Apoptotic markers p-53 and bcl-2 were detected using immunohistological method. Apoptotic index, mitotic index, comparative area of necrotic tissue estimation have been carried out. The unidirectional changes of experimental tumor tissue, the significant tumor growth inhibition, alteration, scar tissue formation, blood circulation disturbances due to FP-8 and 5-fluorouracil administration were shown.

Grygorieva E. V.

2009-01-01

260

Experimental investigation of turbulent flows in pipe junctions  

International Nuclear Information System (INIS)

Branching, three-dimensional, incompressible internal flows are examined in detail in circular pipe configurations at an experimental plant for water and at a test bench for air. Laminar and turbulent flows are made visible in water for Re<5x10"4. Typical phenomena are described in detail, e.g. separations, secondary flows and locally non-stationary behavior under stationary inflow conditions and outflow conditions. Wall pressure distributions for turbulent flows up to Re=10"5 measured at the same test bench supply a good explanation for a number of observed effects. A quantitative investigation of turbulent velocity fields of selected flow cases up to outflow lengths of 10D is carried out in air with the aid of hot-wire anemometry. (orig./DG)

1989-01-01

 
 
 
 
261

Experimental investigation of dynamic photo-thermal effect  

Energy Technology Data Exchange (ETDEWEB)

In an optical interferometer, a part of the laser power is absorbed by the mirrors and gives rise to surface displacements through thermal expansion. The position measurement sensitivity is, therefore, limited by the shot noise of the absorbed radiation. This phenomenon is called the photo-thermal effect and its typical frequency dependence and size can span over several orders of magnitude, depending on the mirror material and temperature, hence it is crucial to have an accurate model extending over such a large range. We present an extensive experimental investigation of dynamic photo-thermal effects, covering more than seven decades in frequency and including finite mirror size effects (low frequency) and coating effects (high frequency) and showing the dependence on the beam waist. A specific extension of the basic model is being developed that can well explain the results.

Rosa, M De [INFN, Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Finland) (Italy); INOA, Sezione di Napoli, Via Campi Flegrei 34, I-80078 Pozzuoli (Namibia) (Italy); Marin, F [INFN, Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Finland) (Italy); Dipartimento di Fisica, Universita di Firenze, and LENS, via Sansone 1, I-50019 Sesto Fiorentino (Finland) (Italy); Marino, F [INFN, Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Finland) (Italy); Arcizet, O [Laboratoire Kastler Brossel, CNRS, Ecole Normale Superieure, Univ. P et M Curie, Case 74, 4 place Jussieu, F75252 Paris, Cedex 05 (France); Heidmann, A [Laboratoire Kastler Brossel, CNRS, Ecole Normale Superieure, Univ. P et M Curie, Case 74, 4 place Jussieu, F75252 Paris, Cedex 05 (France); Pinard, M [Laboratoire Kastler Brossel, CNRS, Ecole Normale Superieure, Univ. P et M Curie, Case 74, 4 place Jussieu, F75252 Paris, Cedex 05 (France)

2006-04-21

262

Experimental investigation of dynamic photo-thermal effect  

International Nuclear Information System (INIS)

In an optical interferometer, a part of the laser power is absorbed by the mirrors and gives rise to surface displacements through thermal expansion. The position measurement sensitivity is, therefore, limited by the shot noise of the absorbed radiation. This phenomenon is called the photo-thermal effect and its typical frequency dependence and size can span over several orders of magnitude, depending on the mirror material and temperature, hence it is crucial to have an accurate model extending over such a large range. We present an extensive experimental investigation of dynamic photo-thermal effects, covering more than seven decades in frequency and including finite mirror size effects (low frequency) and coating effects (high frequency) and showing the dependence on the beam waist. A specific extension of the basic model is being developed that can well explain the results

2006-04-21

263

A preliminary experimental investigation into lateral pedestrian-structure interaction  

DEFF Research Database (Denmark)

This paper presents results from a preliminary experimental study on lateral human-structure dynamic interaction on footbridges using an instrumented platform. The platform has a natural frequency within the range of an average pedestrian and consists of a suspended concrete girder. With a length of 17 m and weight of 19.6 ton, the platform provides a realistic comparison to an actual footbridge. Based on experiments with single pedestrians walking across the platform at resonance, the fundamental dynamic load factor is determined using only the recorded acceleration signal. Furthermore, tests were made with small groups of people to investigate their tendency to synchronise their walking to the motion of the platform. By analysing the recorded acceleration response and video data from the tests, the pedestrian pacing rate distribution and correlated pedestrian force have been identified and are presented herewith. Finally, the results from this study are compared to previous full-scale as well as section model measurements.

Ingólfsson, Einar Thór; Georgakis, Christos

2008-01-01

264

Fibre reinforced composite dental bridge. Part I: Experimental investigation.  

Science.gov (United States)

This experimental investigation aims at revealing the mechanical behaviour and failure pattern of direct fibre-reinforced resin-bonded dental bridge with various designs. To evaluate the overall effects of some newly developed dental materials, in the experiment, genuine composite dental bridge specimens are prepared and tested. The ultimate load, stiffness and mode at the failure of the bridges are measured and compared with the design variations. A good agreement between test and some clinical observations is demonstrated. It is verified that the weakest region appears across the pontic-abutment interface in the composite bridges. This study suggests that the composite bridges reinforced by fibres and supported by adjacent teeth could be of a higher structural strength and stiffness; therefore would provide better clinical performances. PMID:15109860

Li, W; Swain, M V; Li, Q; Ironside, J; Steven, G P

2004-09-01

265

Torque scaling in Taylor-Couette flow — an experimental investigation  

International Nuclear Information System (INIS)

Within this work we investigate experimentally the turbulent flow between two independently rotating concentric cylinders with radius ratio ? = 0.5. The angular velocity of the fluid ? across the gap is measured by Particle Image Velocimetry and Laser Doppler Anemometry for different rotation rates of the inner and outer cylinder. The aim is to analyse the angular momentum transport J?. In relation to this we measure, in addition to the optical methods, the torque effecting at the inner cylinder. For the case that only the outer cylinder rotates and the inner cylinder is at rest, we show, that for this linear stable flow, the torque is comparatively high and its dependency a non-trivial problem.

2011-12-22

266

[Experimental investigation on micro-hollow cathode sustained discharge].  

Science.gov (United States)

Based on micro-hollow cathode discharge (MHCD) as a plasma cathode, a second anode was added to the device for obtaining large volume and uniform plasma at high pressure. The discharge producing condition of MCSD was investigated in the experiments. And the rotational structures of the N2 first positive bands were analyzed with traces of nitrogen added in argon for the measurements of the gas temperature in the MCSD plume. The experimental results show that when the current of the plasma cathode exceeds the threshold, the large volume stable plasma is generated. The gas temperature in the plume is increased a little with increasing the current (0.5-4 mA) and is about 500 K at the pressure of 50 Torr. PMID:21428047

Xia, Guang-Qing; Sadeghi, Nader

2011-01-01

267

Experimental investigation of the Ce-Cu phase diagram  

Energy Technology Data Exchange (ETDEWEB)

Highlights: > We re-investigated the Ce-Cu phase diagram by means of experimental measurements. > Seven temperatures for the invariant reactions were confirmed, while two temperatures for the invariant reactions were revised. > The updated Ce-Cu phase diagram was presented in this work. - Abstract: The binary Ce-Cu system has been re-investigated via the selected eighteen key alloys by means of the differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM) with energy dispersive X-ray analysis techniques. Five intermetallic compounds, Cu{sub 6}Ce, Cu{sub 5}Ce, Cu{sub 4}Ce, Cu{sub 2}Ce, and CuCe, have been confirmed. Cu{sub 6}Ce and Cu{sub 2}Ce melt congruently at 947 deg. C and 810 deg. C, respectively. Cu{sub 5}Ce, Cu{sub 4}Ce, and CuCe are formed through peritectic reactions, L + Cu{sub 6}Ce {r_reversible} Cu{sub 5}Ce at 799 deg. C, L + Cu{sub 5}Ce {r_reversible} Cu{sub 4}Ce at 792 deg. C, and L + Cu{sub 2}Ce {r_reversible} CuCe at 492 deg. C, respectively. Three eutectic reactions, L {r_reversible} (Cu) + Cu{sub 6}Ce at 879 deg. C, L {r_reversible} Cu{sub 4}Ce + Cu{sub 2}Ce at 753 deg. C, and L {r_reversible} CuCe + ({gamma}Ce) at 407 deg. C, have been observed. One catatectic reaction, ({delta}Ce) {r_reversible} L + ({gamma}Ce) at 702 deg. C, was determined. According to the present experimental results, the Ce-Cu phase diagram is revised.

Zhou Huaiying [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Tang Chengying, E-mail: csutcy@163.com [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Tong Minmin; Gu Zhengfei; Yao Qingrong; Rao Guangfei [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China)

2012-01-15

268

The gas fluxing of aluminum: Mathematical modeling and experimental investigations  

Science.gov (United States)

Chlorine fluxing is an essential purification step in aluminum refining in which impurities such as Ca, Na, Li, and Mg are removed by bubbling a mixture of chlorine and argon gas through molten aluminum. The gas is injected into the fluxing vessel through a rotating shaft and impeller which simultaneously agitates the melt, while breaking up and dispersing gas bubbles through the liquid phase. The efficiency of impurity removal and control of toxic chlorine and chloride emissions are dependent upon the extent of gas dispersion or mixing, residence time of the bubbles, and surface area of the bubbles. Clearly the gas injection and distribution within the liquid metal cannot be directly observed and such operations are often poorly controlled and not well understood. Problems arise when the injection gas, i.e. chlorine, is not completely consumed by reaction with impurities and the excess is reported as emissions of chlorides such as toxic HCl. The intention is to improve the technology to eliminate this waste (saving on the energy entailed in the chlorine production and reducing pollution) by better dispersion of the injected gas throughout the metal. Previous experimental investigations using a capacitance probe, capable of immersion in liquid aluminum for several hours, have been carried out to detect bubbles in an industrial fluxing unit at the Alcoa Technical Center. Bubble frequency data have shown the bubbles to be fairly well dispersed in the areas of the fluxing unit, decreasing in observed bubble frequency with increasing distance from the impeller (source of gas injection). To gain further insight and add to our experimental findings, two computational models have been developed to simulate the complex two-phase fluid dynamics of a rotary gas injection system. The results of these two modeling approaches are presented and analyzed and compared to experimental bubble measurements gathered using the capacitance probe. Bubble size distributions and residence times from the discrete phase model were incorporated in an external demagging reaction model to predict chlorine utilization efficiency. This simplified model included several assumptions regarding the kinetics and reaction path, however the model showed reasonable agreement to prior experimental magnesium removal data and provides valuable information related to the interplay of reaction progress in a fluxing unit and the fluid dynamics, in terms of bubble size, trajectory and resulting bubble residence time.

Fjeld, Autumn Marie

269

HESS Opinions On the use of laboratory experimentation: "Hydrologists, bring out shovels and garden hoses and hit the dirt"  

Directory of Open Access Journals (Sweden)

Full Text Available From an outsider's perspective, hydrology combines field work with modelling, but mostly ignores the potential for gaining understanding and conceiving new hypotheses from controlled laboratory experiments. Sivapalan (2009 pleaded for a question- and hypothesis-driven hydrology where data analysis and top-down modelling approaches lead to general explanations and understanding of general trends and patterns. We discuss why and how such understanding is gained very effectively from controlled experimentation in comparison to field work and modelling. We argue that many major issues in hydrology are open to experimental investigations. Though experiments may have scale problems, these are of similar gravity as the well-known problems of fieldwork and modelling and have not impeded spectacular progress through experimentation in other geosciences.

M. van der Perk

2010-02-01

270

Experimental investigations on the heat transfer behaviour of near-surface flowed surfaces; Experimentelle Untersuchungen zum Waermetransportverhalten oberflaechennaher durchstroemter Boeden  

Energy Technology Data Exchange (ETDEWEB)

Since May 2010, the research project 'Energy-optimized construction - Experimental investigations to the verification of a finite element multi-phase model for the heat transfer behaviour in the subsurface' was sponsored by the Federal Ministry of Economics and Technology (Berlin, Federal Republic of Germany). This research contains experimental geothermal investigations from the Institute for Materials and Mechanics in the Building Industry at the Technical University of Darmstadt (Federal Republic of Germany). In addition to extensive field testings, a laboratory test rig for the investigation of the geothermal heat flow and heat transfer has been developed in conjunction with the Institute for Applied Geosciences at the Technical University of Darmstadt. Using this test rig, currently thermal conductivity experiments were performed at different filtration rates, thermal load cases and installation configurations. A large portion of the experimental program at the calibrated equipment has been completed. The authors of the contribution under consideration report on the results of laboratory tests.

Huber, Heiko; Arslan, Ulvi [Technische Univ. Darmstadt (Germany). Inst. fuer Werkstoffe und Mechanik im Bauwesen; Stegner, Johannes; Sass, Ingo [Technische Univ. Darmstadt (Germany). Inst. fuer Angewandte Geowissenschaften

2011-10-24

271

A rule-based decision support application for laboratory investigations management.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The appropriate management of clinical laboratory requests in specialised clinical units often requires the adherence to pre-defined protocols. We evaluated the impact of a rule-based expert system for clinical laboratory investigations management in a pediatric liver transplantation unit of our hospital. After one year, we observed an overall reduction in laboratory resources consumption for transplanted patients (-27%) and a decrease in the percentage of "STAT" requested tests (-44%). The p...

Boon-falleur, L.; Sokal, Etienne; Peters, M.; Ketelslegers, Jean-marie

1995-01-01

272

A Global Remote Laboratory Experimentation Network and the Experiment Service Provider Business Model and Plans  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents results from the IST KAII Trial project ReLAX - Remote LAboratory eXperimentation trial (IST 1999-20827, and contributes with a framework for a global remote laboratory experimentation network supported by a new business model. The paper presents this new Experiment Service Provider business model that aims at bringing physical experimentation back into the learning arena, where remotely operable laboratory experiments used in advanced education and training schemes are made available to a global education and training market in industry and academia. The business model is based on an approach where individual experiment owners offer remote access to their high-quality laboratory facilities to users around the world. The usage can be for research, education, on-the-job training etc. The access to these facilities is offered via an independent operating company - the Experiment Service Provider. The Experiment Service Provider offers eCommerce services like booking, access control, invoicing, dispute resolution, quality control, customer evaluation services and a unified Lab Portal.

Tor Ivar Eikaas

2003-07-01

273

Experimental investigation of the acceleration of deflagration in wake flow  

International Nuclear Information System (INIS)

In gas cloud explosions, turbulence is produced by the flow-field induced by the combustion process. But turbulence can also be produced by an initial flow field, due to atmospheric wind or technical devices. This turbulence may lead to an increased rate of chemical reaction, inducing high pressure levels. The influence of an initial flow field must be taken into account, in connection with safety aspects of nuclear power plants. The reported laboratory-scale experiments were designed to investigate the influence of a flow field, present at the moment of ignition inside a partially-confined hydrocarbon-air cloud. These experiments used a flow channel capable of producing an unsteady flow-field of combustible gas independently of the combustion process itself. The parameters which varied in these tests are: initial flow velocity, gas-mixture composition and geometry. The tests were carried out with stochiometric ethylene-air and propane-air mixtures. The measured quantities are: pressure time history inside the test section. CH-radical radiation. High-speed photographs were also taken. The results show that initial flow speed and reactivity of the mixture have a strong influence on the maximum overpressure and duration of the positive pressure phase, but quenching effects may become important for high flow velocities and mixtures of low reactivity

1983-01-01

274

Experimental Investigations on Airborne Gravimetry Based on Compressed Sensing  

Science.gov (United States)

Gravity surveys are an important research topic in geophysics and geodynamics. This paper investigates a method for high accuracy large scale gravity anomaly data reconstruction. Based on the airborne gravimetry technology, a flight test was carried out in China with the strap-down airborne gravimeter (SGA-WZ) developed by the Laboratory of Inertial Technology of the National University of Defense Technology. Taking into account the sparsity of airborne gravimetry by the discrete Fourier transform (DFT), this paper proposes a method for gravity anomaly data reconstruction using the theory of compressed sensing (CS). The gravity anomaly data reconstruction is an ill-posed inverse problem, which can be transformed into a sparse optimization problem. This paper uses the zero-norm as the objective function and presents a greedy algorithm called Orthogonal Matching Pursuit (OMP) to solve the corresponding minimization problem. The test results have revealed that the compressed sampling rate is approximately 14%, the standard deviation of the reconstruction error by OMP is 0.03 mGal and the signal-to-noise ratio (SNR) is 56.48 dB. In contrast, the standard deviation of the reconstruction error by the existing nearest-interpolation method (NIPM) is 0.15 mGal and the SNR is 42.29 dB. These results have shown that the OMP algorithm can reconstruct the gravity anomaly data with higher accuracy and fewer measurements.

Yang, Yapeng; Wu, Meiping; Wang, Jinling; Zhang, Kaidong; Cao, Juliang; Cai, Shaokun

2014-01-01

275

Experimental Investigations on Airborne Gravimetry Based on Compressed Sensing  

Directory of Open Access Journals (Sweden)

Full Text Available Gravity surveys are an important research topic in geophysics and geodynamics. This paper investigates a method for high accuracy large scale gravity anomaly data reconstruction. Based on the airborne gravimetry technology, a flight test was carried out in China with the strap-down airborne gravimeter (SGA-WZ developed by the Laboratory of Inertial Technology of the National University of Defense Technology. Taking into account the sparsity of airborne gravimetry by the discrete Fourier transform (DFT, this paper proposes a method for gravity anomaly data reconstruction using the theory of compressed sensing (CS. The gravity anomaly data reconstruction is an ill-posed inverse problem, which can be transformed into a sparse optimization problem. This paper uses the zero-norm as the objective function and presents a greedy algorithm called Orthogonal Matching Pursuit (OMP to solve the corresponding minimization problem. The test results have revealed that the compressed sampling rate is approximately 14%, the standard deviation of the reconstruction error by OMP is 0.03 mGal and the signal-to-noise ratio (SNR is 56.48 dB. In contrast, the standard deviation of the reconstruction error by the existing nearest-interpolation method (NIPM is 0.15 mGal and the SNR is 42.29 dB. These results have shown that the OMP algorithm can reconstruct the gravity anomaly data with higher accuracy and fewer measurements.

Yapeng Yang

2014-03-01

276

Experimental investigations on airborne gravimetry based on compressed sensing.  

Science.gov (United States)

Gravity surveys are an important research topic in geophysics and geodynamics. This paper investigates a method for high accuracy large scale gravity anomaly data reconstruction. Based on the airborne gravimetry technology, a flight test was carried out in China with the strap-down airborne gravimeter (SGA-WZ) developed by the Laboratory of Inertial Technology of the National University of Defense Technology. Taking into account the sparsity of airborne gravimetry by the discrete Fourier transform (DFT), this paper proposes a method for gravity anomaly data reconstruction using the theory of compressed sensing (CS). The gravity anomaly data reconstruction is an ill-posed inverse problem, which can be transformed into a sparse optimization problem. This paper uses the zero-norm as the objective function and presents a greedy algorithm called Orthogonal Matching Pursuit (OMP) to solve the corresponding minimization problem. The test results have revealed that the compressed sampling rate is approximately 14%, the standard deviation of the reconstruction error by OMP is 0.03 mGal and the signal-to-noise ratio (SNR) is 56.48 dB. In contrast, the standard deviation of the reconstruction error by the existing nearest-interpolation method (NIPM) is 0.15 mGal and the SNR is 42.29 dB. These results have shown that the OMP algorithm can reconstruct the gravity anomaly data with higher accuracy and fewer measurements. PMID:24647125

Yang, Yapeng; Wu, Meiping; Wang, Jinling; Zhang, Kaidong; Cao, Juliang; Cai, Shaokun

2014-01-01

277

An Experimental Investigation on Inclined Negatively Buoyant Jets  

Directory of Open Access Journals (Sweden)

Full Text Available An experimental study was performed to investigate the behavior of inclined negatively buoyant jets. Such jets arise when brine is discharged from desalination plants. A turbulent jet with a specific salinity was discharged through a circular nozzle at an angle to the horizontal into a tank with fresh water and the spatial evolution of the jet was recorded. Four different initial jet parameters were changed, namely the nozzle diameter, the initial jet inclination, the jet density and the flow rate. Five geometric quantities describing the jet trajectory that are useful in the design of brine discharge systems were determined. Dimensional analysis demonstrated that the geometric jet quantities studied, if normalized with the jet exit diameter, could be related to the densimetric Froude number. Analysis of the collected data showed that this was the case for a Froude number less than 100, whereas for larger values of the Froude number the scatter in the data increased significantly. As has been observed in some previous investigations, the slope of the best-fit straight line through the data points was a function of the initial jet angle (?, where the slope increased with ? for the maximum levels (Ym studied, but had a more complex behavior for horizontal distances.

Raed Bashitialshaaer

2012-09-01

278

Theoretical and experimental investigation of multispectral photoacoustic osteoporosis detection method  

Science.gov (United States)

Osteoporosis is a widespread disorder, which has a catastrophic impact on patients lives and overwhelming related to healthcare costs. Recently, we proposed a multispectral photoacoustic technique for early detection of osteoporosis. Such technique has great advantages over pure ultrasonic or optical methods as it allows the deduction of both bone functionality from the bone absorption spectrum and bone resistance to fracture from the characteristics of the ultrasound propagation. We demonstrated the propagation of multiple acoustic modes in animal bones in-vitro. To further investigate the effects of multiple wavelength excitations and of induced osteoporosis on the PA signal a multispectral photoacoustic system is presented. The experimental investigation is based on measuring the interference of multiple acoustic modes. The performance of the system is evaluated and a simple two mode theoretical model is fitted to the measured phase signals. The results show that such PA technique is accurate and repeatable. Then a multiple wavelength excitation is tested. It is shown that the PA response due to different excitation wavelengths revels that absorption by the different bone constitutes has a profound effect on the mode generation. The PA response is measured in single wavelength before and after induced osteoporosis. Results show that induced osteoporosis alters the measured amplitude and phase in a consistent manner which allows the detection of the onset of osteoporosis. These results suggest that a complete characterization of the bone over a region of both acoustic and optical frequencies might be used as a powerful tool for in-vivo bone evaluation.

Steinberg, Idan; Hershkovich, Hadas Sara; Gannot, Israel; Eyal, Avishay

2014-03-01

279

Experimental investigation of flow instabilities in a laminar separation bubble  

Science.gov (United States)

The present paper reports the results of a detailed experimental study aimed at investigating the dynamics of a laminar separation bubble, from the origin of separation up to the breakdown to turbulence of the large scale coherent structures generated as a consequence of the Kelvin-Helmholtz instability process. Measurements have been performed along a flat plate installed within a double contoured test section, designed to produce an adverse pressure gradient typical of Ultra-High-Lift turbine blade profiles, which induces the formation of a laminar separation bubble at low Reynolds number condition. Measurements have been carried out by means of complementary techniques: hot-wire (HW) anemometry, Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV). The high accuracy 2-dimensional LDV results allow investigating reverse flow magnitude and both Reynolds normal and shear stress distributions along the separated flow region, while the high frequency response of the HW anemometer allows analyzing the amplification process of flow oscillations induced by instability mechanisms. PIV results complement the flow field analysis providing information on the generation and evolution of the large scale coherent structures shed as a consequence of the separated shear layer roll-up, through instantaneous velocity vector maps. The simultaneous analysis of the data obtained by means of the different measuring techniques allows an in depth view of the instability mechanisms involved in the transition/reattachment processes of the separated shear layer.

Simoni, D.; Ubaldi, M.; Zunino, P.

2014-06-01

280

Advanced Laboratory at Texas State University: Error Analysis, Experimental Design, and Research Experience for Undergraduates  

Science.gov (United States)

Physics is an experimental science. In other words, all physical laws are based on experimentally observable phenomena. Therefore, it is important that all physics students have an understanding of the limitations of certain experimental techniques and the associated errors associated with a particular measurement. The students in the Advanced Laboratory class at Texas State perform three detailed laboratory experiments during the semester and give an oral presentation at the end of the semester on a scientific topic of their choosing. The laboratory reports are written in the format of a ``Physical Review'' journal article. The experiments are chosen to give the students a detailed background in error analysis and experimental design. For instance, the first experiment performed in the spring 2009 semester is entitled Measurement of the local acceleration due to gravity in the RFM Technology and Physics Building. The goal of this experiment is to design and construct an instrument that is to be used to measure the local gravitational field in the Physics Building to an accuracy of ±0.005 m/s^2. In addition, at least one of the experiments chosen each semester involves the use of the research facilities within the physics department (e.g., microfabrication clean room, surface science lab, thin films lab, etc.), which gives the students experience working in a research environment.

Ventrice, Carl

2009-04-01

 
 
 
 
281

Accelerator laboratories: development centers for experimental physics and technology in Mexico  

International Nuclear Information System (INIS)

Three years ago in this Nuclear Center the author and Professor Graef expounded the inception and development of experimental physics and new techniques centered about laboratories and equipped in our country with positive ion accelerators. Extracted here is the information on the laboratories that have allowed professional training as well as the furtherance of scientific productivity in each group. An additional proposal as to how the technical groups knowledgeable in advanced technology might contribute significantly to adequate preparation of youth at the intermediate level able to generate innocuous micro industries in their own neighbourhood. (Author). 5 refs, 2 figs, 2 tabs

1989-05-25

282

Calculation and experimental investigation of multi-component ceramic systems  

International Nuclear Information System (INIS)

This work shows a way to combine thermodynamic calculations and experiments in order to get useful information on the constitution of metal/non-metal systems. Many data from literature are critically evaluated and used as a basis for experiments and calculations. The following multi-component systems are treated: 1. Multi-component systems of 'ceramic' materials with partially metallic bonding (carbides, nitrides, oxides, borides, carbonitrides, borocarbides, oxinitrides of the 4-8th transition group metals) 2. multi-component systems of non-metallic materials with dominant covalent bonding (SiC, Si_3N_4, SiB_6, BN, Al_4C_3, Be_2C) 3. multi-component systems of non-metallic materials with dominant heteropolar bonding (Al_2O_3, TiO_2, BeO, SiO_2, ZrO_2). The interactions between 1. and 2., 2. and 3., 1. and 3. are also considered. The latest commercially available programmes for the calculation of thermodynamical equilibria and phase diagrams are evaluated and compared considering their facilities and limits. New phase diagrams are presented for many presently unknown multi-component systems; partly known systems are completed on the basis of selected thermodynamic data. The calculations are verified by experimental investigations (metallurgical and powder technology methods). Altogether 690 systems are evaluated, 126 are calculated for the first time and 52 systems are experimentally verified. New data for 60 ternary phases are elaborated by estimating the data limits for the Gibbs energy values. A synthesis of critical evaluation of literature, calculations and experiments leads to new important information about equilibria and reaction behaviour in multi-component systems. This information is necessary to develop new stable and metastable materials. (orig./MM)

1994-01-01

283

Experimental investigation on compaction properties of sandy soils  

International Nuclear Information System (INIS)

In this research, an effort has been made to develop a correlation between standard and modified proctor compaction test parameters, i.e., maximum dry unit weight (gamma dmax) and optimum moisture content (OMC) of sandy soils. Standard and modified proctor along with classification tests were carried out on hundred and twenty sandy soil samples with different grain size distributions. Based on the test results, the soil samples were classified into various groups of medium to fine sand with non-plastic fines up to 45%. Regression analyses were performed on the experimental data and correlations were proposed to express modified Proctor parameters (gamma dmod and OMC mod) in term of standard Proctor test parameters (gamma dstd and OMC std). The validation of the proposed predictive correlations was done by using test results of another set of sandy soil samples not used in the development of the correlations. The results of the analyses showed that variation between experimental and predicted values of gamma dmod is within +- 4 % confidence interval and that of OMC mod is within +- 2.0 %. Further, based on the test results, an effort has been made to investigate the effect of fines (finer than 75 mu m) on compaction characteristics. It was observed that gamma dmax both in case of standard and modified proctor increases with increase in fines content up to 35% and beyond that it decreases. However, the value of OMC in both the cases decreases with increase in fine content. The correlations proposed in this paper may be very useful during the project preliminary/ pre-feasibility stages in the field of Geotechnical Engineering. (author)

2014-01-01

284

Experimental Investigation of White Layer formation in Hard Turning  

Science.gov (United States)

Hard turning with super hard cutting tools, like PCBN or Ceramics inserts, represents an interesting advance in the manufacturing industry, regarding the finishing of hardened steels. This innovative machining technique is considered an attractive alternative to traditional finish grinding operations because of the high flexibility, the ability to achieve higher metal removal rates, the possibility to operate without the use of coolants, and the capability to achieve comparable workpiece quality. However, the surface integrity effects of hard machining need to be taken into account due to their influence on the life of machined components. In particular, the formation of a usually undesirable white layer at the surface needs further investigation. Three different mechanisms have been proposed as main responsible of the white layer genesis: (i) microstructural phase transformation due to a rapid heating and quenching, (ii) severe plastic deformation resulting in a homogenous structure and/or a very fine grain size microstructure; (iii) surface reaction with the environment. In this research, an experimental campaign was carried out and several experimental techniques were used in order to analyzed the machined surface and to understand which of the above mentioned theories is the main cause of the white layer formation when AISI 52100 hardened steel is machined by PCBN inserts. In particular, the topography characterization has obtained by means of optical and scanning electron microscope (SEM) while microstructural phase composition and chemical characterization have been respectively detected using X-ray Diffraction (XRD) and Energy-dispersive X-ray spectroscopy (EDS) techniques. The results prove that the white layer is the result of microstructural alteration, i.e. the generation of a martensitic structure.

Umbrello, D.; Rotella, G.; Crea, F.

2011-05-01

285

Experimental investigation of the stent-artery interaction.  

Science.gov (United States)

It is well acknowledged that stent implantation causes abnormal stretch and strains on the arterial wall, which contribute to the formation and progression of restenosis. However, the experimental characterization of the strain field on the stented vessel is scant. In this work, the balloon-expandable stent implantation inside an artery analogue was captured through two high-speed CCD cameras. The surface strain maps on the stented tube were quantified with a 3-D digital image correlation technique. The strain history at one specific reference point illustrated three stenting phases, including balloon inflation, pressurization and deflation. The surface strain distributions along one axial path were obtained at various time points to demonstrate the stent-vessel interactions. The radial wall thickness reduction history was used to evaluate the pressure-diameter relationship for the balloon. Results indicated that the expansion process of the balloon was significantly altered by the external loadings from both the stent and artery analogue. In addition, the repeatability of the stenting experiments was demonstrated through two tests with a change of 5% in the stent-induced maximum first principal strain. Moreover, a computational model of the stenting procedure was developed to recapture the stenting experiments. Comparison between experiments and simulation showed a difference of 7.17% in the first principal strain averaged over the high strain area. This indicated the validation of the computational framework, which can be used to investigate the strain or stress field throughout the computational domain, a feature that is not affected by experimental techniques. PMID:24044587

Zhao, Shijia; Gu, Linxia; Froemming, Stacey R

2013-10-01

286

Theoretical and experimental investigation of cappillary electrolysis system  

International Nuclear Information System (INIS)

In a fusion reactor environment, it is expected that highly tritiated water will be formed when tritium is extracted from the blanket as well as during the plasma exhaust purification process. As a consequence, the recovery of elemental tritium from its oxides is an essentrial step before recycling the fuel to the reactor. Among different basic processes that can be used for this purpose, electrolysis appears to be very promising. Therefore, SCK/CEN has developed a small dedicated cell designed to decompose 100 ml/day of pure DTO or HTO. At the present project stage, a prototype cell is available and the device has been successfully tested with light water during several thousands of hours. In the orginal concept, the liquid inventory is limited to the vertical porous gas separator. Capillarity is used as a driving force to feed the cell to avoid the use of a pump. This fact turns out to have a considerable influence on the behaviour of the electrolytic system. This particular behaviour has been theorectically investigated with the aim to allow a better basic understanding of the capillary electrolysis. A deterministic model has been developed for its purpose. The mathematical equations show clearly that the electrolyte tends to accumulate at the top of the gas separator. An equilibrium state can be reached only if sufficiently large amounts of electrolyte can flow back towards the bottom of the gas separator. This counter-flow has been taken into account by introducing a single general diffusion coefficient into the model. In a second phase, systematic experimental runs have been carried out with mock-up cells. A statistical treatment based on the maximum likelihood estimation algorithm allowed to compute the best values for the diffusion coefficient and to validate the model. Finally, acceptabel ranges of the independent varialbles have been defined and all the subsequent experimental runs have been performed without stability problems. (author). 12 refs.; 5 figs.; 1 tab

1989-01-01

287

REVIEW OF EXPERIMENTAL STUDIES INVESTIGATING THE RATE OF STRONTIUM AND ACTINIDE ADSORPTION BY MONOSODIUM TITANATE  

Energy Technology Data Exchange (ETDEWEB)

A number of laboratory studies have been conducted to determine the influence of mixing and mixing intensity, solution ionic strength, initial sorbate concentrations, temperature, and monosodium titanate (MST) concentration on the rates of sorbate removal by MST in high-level nuclear waste solutions. Of these parameters, initial sorbate concentrations, ionic strength, and MST concentration have the greater impact on sorbate removal rates. The lack of a significant influence of mixing and mixing intensity on sorbate removal rates indicates that bulk solution transport is not the rate controlling step in the removal of strontium and actinides over the range of conditions and laboratory-scales investigated. However, bulk solution transport may be a significant parameter upon use of MST in a 1.3 million-gallon waste tank such as that planned for the Small Column Ion Exchange (SCIX) program. Thus, Savannah River National Laboratory (SRNL) recommends completing the experiments in progress to determine if mixing intensity influences sorption rates under conditions appropriate for this program. Adsorption models have been developed from these experimental studies that allow prediction of strontium (Sr), plutonium (Pu), neptunium (Np) and uranium (U) concentrations as a function of contact time with MST. Fairly good agreement has been observed between the predicted and measured sorbate concentrations in the laboratory-scale experiments.

Hobbs, D.

2010-10-01

288

An experimental investigation of pump as turbine for micro hydro application  

Science.gov (United States)

This paper presents the results of an experimental investigation of a centrifugal pump working as turbine (PAT). An end suction centrifugal pump was tested in turbine mode at PAT experimental rig installed in the Mechanical Engineering Laboratory of Universiti Tenaga Nasional. The pump with specific speed of 15.36 (m, m3/s) was used in the experiment and the performance characteristic of the PAT was determined. The experiment showed that a centrifugal pump can satisfactorily be operated as turbine without any mechanical problems. As compared to pump operation, the pump was found to operate at higher heads and discharge values in turbine mode. The best efficiency point (BEP) in turbine mode was found to be lower than BEP in pump mode. The results obtained were also compared to the work of some previous researchers.

>N Raman, I Hussein,

2013-06-01

289

An experimental investigation of pump as turbine for micro hydro application  

International Nuclear Information System (INIS)

This paper presents the results of an experimental investigation of a centrifugal pump working as turbine (PAT). An end suction centrifugal pump was tested in turbine mode at PAT experimental rig installed in the Mechanical Engineering Laboratory of Universiti Tenaga Nasional. The pump with specific speed of 15.36 (m, m3/s) was used in the experiment and the performance characteristic of the PAT was determined. The experiment showed that a centrifugal pump can satisfactorily be operated as turbine without any mechanical problems. As compared to pump operation, the pump was found to operate at higher heads and discharge values in turbine mode. The best efficiency point (BEP) in turbine mode was found to be lower than BEP in pump mode. The results obtained were also compared to the work of some previous researchers.

2013-06-17

290

Laboratory investigations of the role of the grain surface in astrochemical models.  

Science.gov (United States)

The rich chemistry often detected in star forming regions is now recognized to be a consequence of solid-state astrochemistry and the thermal desorption of its products. In recent experimental studies, desorption of a range of ices from a gold surface was investigated using temperature programmed desorption (TPD). These data were then used in astrochemical models. In this paper we investigate the sensitivity of these models to the inclusion of TPD data obtained from different surfaces (simulating different dust grains) and different thicknesses of the icy mantles. Detailed laboratory TPD studies of the desorption of ices from a highly oriented pyrolytic graphite (HOPG) surface have been performed. Desorption temperatures and kinetic parameters have been determined directly from the TPD data and have been used to determine the expected desorption temperature for the ices from grain surfaces. The results of these experiments have been incorporated into astrochemical models of high mass star forming regions and have then been compared with the results of previous experiments. From this comparison, we are able to determine whether the nature and composition of the grain surface is important in dictating the chemistry that occurs in star forming regions. PMID:17191445

Brown, Wendy A; Viti, Serena; Wolff, Angela J; Bolina, Amandeep S

2006-01-01

291

Experimental investigations of the vertically loaded small scale bored piles  

Directory of Open Access Journals (Sweden)

Full Text Available At present, while evaluating bored piles load capacity in clay soils by CPT data, the depth of active area below the end face plane, within which the averaging of CPT values takes place, is taken as different in different Codes. Thus, for instance, in native Codes and Recommendations the depth of active area is taken from 2 to 4 pile diameters. In foreign Codes such as Belorussian, the depth of active area is taken up to 4 pile diameters and in European Codes - within 0,8-4 pile diameters. In order to specify the regularities of active area forming at different stages of loading, in-situ experimental investigations of large scale models have been carried out. At the test site, two small scale bored piles with the diameter of 130 mm were penetrated into the soil to the depth of 1100 m. The investigations were carried out in two stages: the first - pile static test with measuring of soil vertical displacements with the help of deep marks; the second - digging out soil around the pile and soil sampling at different depths. According to the results of the investigations carried out, the depth of the active area while reaching the limit state was determined to be about two pile diameters. With significant pile settlements (more than 0,58 d, the dimensions of this area do not exceed three pile diameters below the end face plane, and two diameters to the side from the pile axis. Within the lateral surface the significant variation of soil physical characteristics appears to be at the distance not less than 0,4 pile diameter from the lateral surface. Due to investigations’ results, it can be noted that in case of bored pile load less than the limit one, the depth of the active area is about two pile diameters. When the pile reaches its limit state, that provokes significant settlements, zone of compaction does not exceed three diameters to the depth and two diameters to the side from the pile axis.

Glazachev Anton Olegovich

2014-04-01

292

Experimental investigation of single carbon compounds under hydrothermal conditions  

Science.gov (United States)

The speciation of carbon in subseafloor hydrothermal systems has direct implications for the maintenance of life in present-day vent ecosystems and possibly the origin of life on early Earth. Carbon monoxide is of particular interest because it represents a key reactant during the abiotic synthesis of reduced carbon compounds via Fischer-Tropsch-type processes. Laboratory experiments were conducted to constrain reactions that regulate the speciation of aqueous single carbon species under hydrothermal conditions and determine kinetic parameters for the oxidation of CO according to the water water-gas shift reaction (CO 2 + H 2 = CO + H 2O). Aqueous fluids containing added CO 2, CO, HCOOH, NaHCO 3, NaHCOO, and H 2 were heated at 150, 200, and 300 °C and 350 bar in flexible-cell hydrothermal apparatus, and the abundances of carbon compounds was monitored as a function of time. Variations in fluid chemistry suggest that the reduction of CO 2 to CH 3OH under aqueous conditions occurs via a stepwise process that involves the formation of HCOOH, CO, and possibly CH 2O, as reaction intermediaries. Kinetic barriers that inhibit the reduction of CH 3OH to CH 4 allow the accumulation of reaction intermediaries in solution at high concentrations regulated by metastable thermodynamic equilibrium. Reaction of CO 2 to CO involves a two-step process in which CO 2 initially undergoes a reduction step to HCOOH which subsequently dehydrates to form CO. Both reactions proceed readily in either direction. A preexponential factor of 1.35 × 10 6 s -1 and an activation energy of 102 kJ/mol were retrieved from the experimental results for the oxidation of CO to CO 2. Reaction rates amongst single carbon compounds during the experiments suggest that ?CO 2 (CO 2 + HCO 3- + CO 32-), CO, ?HCOOH (HCOOH + HCOO -), and CH 3OH may reach states of redox-dependent metastable thermodynamic equilibrium in subseafloor and other hydrothermal systems. The abundance of CO under equilibrium conditions is strongly dependent on temperature, the total carbon content of the fluid, and host-rock lithology. If crustal residence times following the mixing of high-temperature hydrothermal fluids with cool seawater are sufficiently long, reequilibration of aqueous carbon can result in the generation of additional reduced carbon species such as HCOOH and CH 3OH, and the consumption of H 2. The present study suggests that abiotic reactions involving aqueous carbon compounds in hydrothermal systems are sufficiently rapid to influence metabolic pathways utilized by organisms that inhabit vent environments.

Seewald, Jeffrey S.; Zolotov, Mikhail Yu.; McCollom, Thomas

2006-01-01

293

Experimental investigation of the turbulent structures that initiate bedload motion  

Science.gov (United States)

Knowledge of the coupling between turbulent structures and the subsequent motion of bed grains is important to formulating sediment transport relations in complex turbulent flows. Previous experiments involving measurements of forces on fixed particles have shown that bed grains experience fluctuations in drag and lift that are several times the mean, and these high drag and lift events are well correlated with positive fluctuations in downstream velocity near the particle. In order to extend these experiments to the initial motion of grains that are not fixed, laboratory flume measurements of the initial motion of glass spheres were conducted using a high-resolution (1280X1024 pixels) and high-speed digital video camera at a rate of 400 frames per second. Six experimental runs were conducted on each of four spheres having diameters of 1.1, 1.6, 2.5, and 3.6 cm. Each of these spheres was placed on a bed pocket formed by three other 2.5cm glass spheres that were glued together to form a known bed-pocket angle. All of the spheres were entrained at approximately the same discharge. A 1.3 mm thick laser light sheet aligned parallel to the flume walls illuminated flow seed particles in a two-dimensional plane that included the center of the test sphere. Two-dimensional velocity fields were calculated for all successive pairs of images in the video sequence using particle imaging velocimetry (PIV) algorithms. Results showed that the downstream velocity immediately upstream of the test sphere at the initiation of motion was generally 2-3 standard deviations greater than the local mean velocity. The vertical extent of the volume of high-speed fluid that caused the sphere to begin motion generally extended less than two median bed-grain diameters above the bed. A volume of relatively slow moving fluid was generally found above this volume of near-bed high-speed fluid. Thus, to observe the turbulent structures that cause particle entrainment in a gravel bed requires measurements within a couple grain diameters of the bed.

Schmeeckle, M. W.; Nelson, J. M.; Shreve, R. L.

2004-12-01

294

An experimental facility to investigate missile impact on small scale concrete elements  

International Nuclear Information System (INIS)

The necessity to design nuclear power plants for extreme load conditions is now well recognised. These load conditions include aircraft and missile impact. The behaviour of structures under such conditions and the extent of influence of various parameters is not yet clearly defined. Research is still in progress in such areas to assess the local and global response of structures subjected to impact. One possible avenue of research is experimental investigation. Scaled testing of the impact problem has also been proved to give sufficiently accurate results. However the fact that velocity of impact cannot be scaled down according to the dynamic scaling laws has confined the investigations to laboratories which have a facility to launch high velocity projectiles. UKAEA in Winfrith, UK, and, Meppen and Foulness in Germany are three of the laboratories where such launching facilities are available. Models scaled to 1/20th to 1/25th of the prototype are reasonably accurate. Impact, being a highly dynamic phenomenon with transient forces lasting only a few milliseconds requires instrumentation with good dynamic response. This paper explains in detail an experimental setup developed to test small scale specimens of slabs and shells under missile impact at a velocity of around 200m/s

1993-08-15

295

Analytical and experimental Mark I boiling water reactor containment safety research at the Lawrence Livermore Laboratory  

International Nuclear Information System (INIS)

An overview of research work is discussed here which adresses both large scale experimental and multidimensional analytical containment studies conducted at the Lawrence Livermore Laboratory since 1976. The Mark I Boiling Reactor (BWR) containment design is the subject of interest. In the experimental program, particular focus is placed on quantification of loss-off-coolant-accident (LOCA) induced loads. The focus of the analytical effort is toward understanding of fluid/structure interaction effects due both to LOCA induced loads and safety relief value (SRV) loads in the Mark I BWR pressure suppression wetwell (a segmented torus). (orig.)

1979-08-21

296

A novel self-excited self-regulated single phase induction generator; Part II: Experimental investigation  

Energy Technology Data Exchange (ETDEWEB)

Part 1 of this paper presents the basic system, theoretical modeling and typical test results of a novel Self-Excited Regulated Induction Generator. In this part the results of a detailed experimental investigation are presented to assess its suitability for practical applications. The steady state performance of the self-excited single phase induction generator (SEIG), maintaining the terminal voltage within a close range is investigated under realistic loading conditions in the laboratory. Detailed experimental results are presented and discussed. Necessary tests to obtain machine parameters for theoretical modeling are also developed and relevant results of the prototype presented. The effects of series and shunt capacitors, prime mover speed, load and load power factor are investigated. It has been shown to exhibit better voltage waveform as compared to commercially available sets. The experimental results confirm that this new generating system can be favorably employed for use as a small portable generator driven by nearly constant speed prime movers such as oil engines or Hydro Turbines.

Murthy, S.S.; Tandon, A.K. (Indian Inst. of Tech., Delhi, New Delhi (India). Dept. of Electrical Engineering); Rai, H.C. (Jamia Millia Islania, New Delhi (India). Dept. of Electrical Engineering)

1993-09-01

297

Experimental investigation of an indirect type natural convection solar dryer  

Energy Technology Data Exchange (ETDEWEB)

An indirect type natural convection solar dryer is designed, constructed and investigated experimentally under Tanta prevailing weather conditions. The system consists of a flat plate solar air heater connected to a cabinet acting as a drying chamber. The air heater is designed to be able to insert various storage materials under the absorber plate in order to improve the drying process. Sand is used as the storage material. Drying experiments have been conducted with and without storage materials for different spherical fruits, such as seedless grapes, figs and apples, as well as vegetables, such as green peas, tomatoes and onions. The solar irradiance, temperature distribution in different parts of the system, ambient temperature and relative humidity of the inlet and outlet drying air have been recorded. The equilibrium moisture content M{sub e} for seedless grapes is reached after 60 and 72 h when the system is used with and without storage material, respectively. Therefore, the storage material reduces the drying process by 12 h. In order to accelerate the drying process, the drying products are divided into pieces and then chemically treated by dipping the samples into boiling water containing 0.4% olive oil and 0.3% NaOH for 60 s. However, the required time to achieve M{sub e} for the chemically treated seedless grapes, when the system is used with sand as a storage material, is drastically reduced to 8 h. Moreover, we found that the storage and chemical pretreatment have caused significant decreases of the drying time for all the investigated crops. The present system is capable of drying 10 kg of chemically treated grapes or green peas during 20 h of sunshine. (author)

El-Sebaii, A.A.; Aboul-Enein, S.; Ramadan, M.R.I.; El-Gohary, H.G. [Tanta Univ. (Egypt). Dept. of Physics

2002-11-01

298

21 CFR 312.160 - Drugs for investigational use in laboratory research animals or in vitro tests.  

Science.gov (United States)

...in laboratory research animals or in vitro tests. 312.160 Section 312...in Laboratory Research Animals or In Vitro Tests § 312.160 Drugs for investigational...in laboratory research animals or in vitro tests. (a) Authorization to...

2009-04-01

299

Numerical and experimental investigations on unsteady aerodynamics of flapping wings  

Science.gov (United States)

The development of a dynamic unstructured grid high-order accurate spectral difference (SD) method for the three dimensional compressible Navier-Stokes (N-S) equations and its applications in flapping-wing aerodynamics are carried out in this work. Grid deformation is achieved via an algebraic blending strategy to save computational cost. The Geometric Conservation Law (GCL) is imposed to ensure that grid deformation will not contaminate the flow physics. A low Mach number preconditioning procedure is conducted in the developed solver to handle the bio-inspired flow. The capability of the low Mach number preconditioned SD solver is demonstrated by a series of two dimensional (2D) and three dimensional (3D) simulations of the unsteady vortex dominated flow. Several topics in the flapping wing aerodynamics are numerically and experimentally investigated in this work. These topics cover some of the cutting-edge issues in flapping wing aerodynamics, including the wake structure analysis, airfoil thickness and kinematics effects on the aerodynamic performances, vortex structure analysis around 3D flapping wings and the kinematics optimization. Wake structures behind a sinusoidally pitching NACA0012 airfoil are studied with both experimental and numerical approaches. The experiments are carried out with Particle Image Velocimetry (PIV) and two types of wake transition processes, namely the transition from a drag-indicative wake to a thrust-indicative wake and that from the symmetric wake to the asymmetric wake are distinguished. The numerical results from the developed SD solver agree well with the experimental results. It is numerically found that the deflective direction of the asymmetric wake is determined by the initial conditions, e.g. initial phase angle. As most insects use thin wings (i. e., wing thickness is only a few percent of the chord length) in flapping flight, the effects of airfoil thickness on thrust generation are numerically investigated by simulating the flow fields around a series of plunging NACA symmetric airfoils with thickness ratio ranging from 4.0% to 20.0% of the airfoil chord length. The contribution of viscous force to flapping propulsion is accessed and it is found that viscous force becomes thrust producing, instead of drag producing, and plays a non-negligible role in thrust generation for thin airfoils. This is closely related to the variations of the dynamics of the unsteady vortex structures around the plunging airfoils. As nature flyers use complex wing kinematics in flapping flight, kinematics effects on the aerodynamic performance with different airfoil thicknesses are numerically studied by using a series of NACA symmetric airfoils. It is found that the combined plunging and pitching motion can outperform the pure plunging or pitching motion by sophisticatedly adjusting the airfoil gestures during the oscillation stroke. The thin airfoil better manipulates leading edge vortices (LEVs) than the thick airfoil (NACA0030) does in studied cases, and there exists an optimal thickness for large thrust generation with reasonable propulsive efficiency. With the present kinematics and dynamic parameters, relatively low reduced frequency is conducive for thrust production and propulsive efficiency for all tested airfoil thicknesses. In order to obtain the optimal kinematics parameters of flapping flight, a kinematics optimization is then performed. A gradient-based optimization algorithm is coupled with a second-order SD Navier-Stokes solver to search for the optimal kinematics of a certain airfoil undergoing a combined plunging and pitching motion. Then a high-order SD scheme is used to verify the optimization results and reveal the detailed vortex structures associated with the optimal kinematics of the flapping flight. It is found that for the case with maximum propulsive efficiency, there exists no leading edge separation during most of the oscillation cycle. In order to provide constructive suggestions to the design of micro-air-vehicles (MAVs), 3D simulations of the flapping wings are carrie

Yu, Meilin

300

Experimental Investigation of High Temperature Superconducting Imaging Surface Magnetometry  

Energy Technology Data Exchange (ETDEWEB)

The behavior of high temperature superconducting quantum interference devices (SQUIDs) in the presence of high temperature superconducting surfaces has been investigated. When current sources are placed close to a superconducting imaging surface (SIS) an image current is produced due to the Meissner effect. When a SQUID magnetometer is placed near such a surface it will perform in a gradiometric fashion provided the SQUID and source distances to the SIS are much less than the size of the SIS. We present the first ever experimental verification of this effect for a high temperature SIS. Results are presented for two SQUID-SIS configurations, using a 100 mm diameter YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} disc as the SIS. These results indicate that when the current source and sensor coil (SQUID) are close to the SIS, the behavior is that of a first-order gradiometer. The results are compared to analytic solutions as well as the theoretical predictions of a finite element model.

Espy, M.A.; Matlachov, A.N.; Kraus, R.H., Jr.

1999-06-21

 
 
 
 
301

Numerical and experimental investigation of a mild combustion burner  

Energy Technology Data Exchange (ETDEWEB)

An industrial burner operating in the MILD combustion regime through internal recirculation of exhaust gases has been characterized numerically. To develop a self-sufficient numerical model of the burner, two subroutines are coupled to the CFD solver to model the air preheater section and heat losses from the burner through radiation. The resulting model is validated against experimental data on species concentration and temperature. A 3-dimensional CFD model of the burner is compared to an axisymmetric model, which allows considerable computational saving, but neglects some important burner features such as the presence of recirculation windows. Errors associated with the axisymmetric model are evaluated and discussed, as well as possible simplified procedures for engineering purposes. Modifications of the burner geometry are investigated numerically and suggested in order to enhance its performances. Such modifications are aimed at improving exhaust gases recirculation which is driven by the inlet air jet momentum. The burner is found to produce only 30 ppm{sub v} of NO when operating in MILD combustion mode. For the same air preheating the NO emissions would be of approximately 1000 ppm{sub v} in flame combustion mode. It is also shown that the burner ensures more homogeneous temperature distribution in the outer surfaces with respect to flame operation, and this is attractive for burners used in furnaces devoted to materials' thermal treatment processes. The effect of air excess on the combustion regime is also discussed. (author)

Galletti, Chiara; Parente, Alessandro; Tognotti, Leonardo [Department of Chemical Engineering, Industrial Chemistry and Materials Science, University of Pisa, via Diotisalvi 2, 56126 Pisa (Italy)

2007-12-15

302

An experimental investigation of iso-octane ignition phenomena  

Energy Technology Data Exchange (ETDEWEB)

High-speed digital imaging has been used in rapid compression facility (RCF) studies to investigate ignition phenomena of iso-octane/air mixtures. Sequential images were captured for each experiment. The results indicate the existence of two ignition regimes. In one domain, ignition is rapid, typically less than 76 {mu}s, and ignition occurs simultaneously throughout the test volume. In the other domain, reaction fronts form and propagate within the test volume prior to volumetric ignition. The data span equivalence ratios from {phi}=0.20 to 1.98, with inert/O{sub 2} gas ratios from 1.38 to 5.89, pressures from 8.7 to 16.6 atm, and temperatures from 903 to 1020 K. The transition between the two regimes is discussed in the context of the mixture composition and experimental conditions. The analysis shows that the fuel mole fraction is a key parameter dictating the boundary between the modes of ignition. Below a critical mole fraction limit, volumetric ignition is observed; above the critical limit, reaction fronts are consistently present prior to volumetric ignition. The ignition delay times for both ignition regimes are well reproduced using a homogeneous simulation with detailed reaction chemistry, when the state conditions are modified to account for the presence of the reaction fronts. The results are discussed in terms of proposed reaction chemistry, ignition theory, and previous studies of iso-octane ignition. (author)

Walton, S.M.; He, X.; Zigler, B.T.; Wooldridge, M.S.; Atreya, A. [Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109-2125 (United States)

2007-08-15

303

Border Collision Route to Quasiperiodicity: Numerical Investigation and Experimental Confirmation  

DEFF Research Database (Denmark)

Numerical studies of higher-dimensional piecewise-smooth systems have recently shown how a torus can arise from a periodic cycle through a special type of border-collision bifurcation. The present article investigates this new route to quasiperiodicity in the two-dimensional piecewise-linear normal form map. We have obtained the chart of the dynamical modes for this map and showed that border-collision bifurcations can lead to the birth of a stable closed invariant curve associated with quasiperiodic or periodic dynamics. In the parameter regions leading to the existence of an invariant closed curve, there may be transitions between an ergodic torus and a resonance torus, but the mechanism of creation for the resonance tongues is distinctly different from that observed in smooth maps. The transition from a stable focus point to a resonance torus may lead directly to a new focus of higher periodicity, e.g., a period-5 focus. This article also contains a discussion of torus destruction via a homoclinic bifurcation in the piecewise-linear normal map. Using a dcâ??dc converter with two-level control as an example, we report the first experimental verification of the direct transition to quasiperiodicity through a border-collision bifurcation. ©2006 American Institute of Physics

Zhusubaliyev, Zhanybai; Mosekilde, Erik

2006-01-01

304

Experimental investigation of the origin of the Ti K?'' satellites  

International Nuclear Information System (INIS)

The Ti K?'' satellite is investigated using a Johann-type spectrometer on the BL15XU undulator beam line of SPring-8 at excitation energies between 4996 and 7000 eV. The intensity of the K?'' satellite relative to that of K?1,2 exhibits an abrupt jump from 0% to ?1% in a range of 10 eV around an excitation energy of 5010 eV. The energy range to reach saturation is ?500 eV. The creation of spectator holes is implicated to be due to shake-up processes, inducing the emergence of the K?'' satellite. The onset energy for the appearance of the satellite is 5011.0 eV±0.8 eV, corresponding to the [1s3p] double-ionization threshold energy by a Z+1 approximation. The experimental results obtained in this work confirm that the K?'' satellite originates from a 3p spectator hole, as predicted theoretically by Scott [ Phys. Rev. A 34, 4438 (1986)

2004-05-01

305

Experimental Investigation on Characteristics of Polythene Waste Incorporated Concrete  

Directory of Open Access Journals (Sweden)

Full Text Available The Disposal of large quantity of plastic cover may cause pollution of land, water bodies and air. The proposed concrete which is made up by adding plastic in concrete may help to reuse the plastic cover as one of the constituent’s material of concrete, to improve the certain properties of concrete. The properties of concrete as varying percentages of plastic will test for compressive strength and Split tensile strength and flexural strength shows that an appreciable improvement in tensile strength of concrete can be achieved by introducing cut pieces of plastic cover. This paper presents the experimental investigation of feasibility of polythene cover post consumer waste used for food packaging. The numbers of samples is prepared in M25 concrete mix with required water/ cement ratio. Plastic waste was converted in to fiber size form and added waste for three aspect ratios, is casted into desire shape and size as per requirement of the tests. Each specimen was cured for 7 days, 14 days, and 28 days. The workability of compression, tension and flexural tests were carried out. The results are compared with normal concrete was observed.

J. Simson Jose

2014-04-01

306

Experimental investigation on laser removal of carbon and tungsten particles  

International Nuclear Information System (INIS)

During the operation of the ITER fusion facility, particles with size from 10 nm to 100 ?m, mainly composed of carbon, beryllium, and tungsten, will be produced. Since dust could lead to safety issues, it must be periodically removed from the facility in order to keep their quantity below the safety limit requirements. In this context, laser cleaning appeared as a very promising technique, and investigations have to be done to understand the physical processes and optimize the procedure. Several experiments were carried out to improve the understanding of the phenomena involved during the laser-induced removal of Carbon particles. The ejection mechanisms have been experimentally studied for different irradiation conditions with nanosecond laser pulses. The removal efficiency and the fluence threshold were determined by optical microscopy. The influence of the substrate was studied for the dry laser cleaning configuration. This study presents scanning electronic microscopy pictures which show that the particle removal leads to a damage of the substrate. These damages give evidences on the ablation mechanism. The laser shock cleaning was also studied. In this configuration, the laser-induced shock wave can be used to push the particles away from the surface. This technique appears to be very useful to clean shadowed areas

2009-03-01

307

Experimental Investigation of Cavitation Induced Feedline Instability from an Orifice  

Science.gov (United States)

This paper details the results of an experimental investigation into the cavitation instabilities created by a circular orifice conducted at the University of Alabama in Huntsville Propulsion Research Center. This experiment was conducted in concert with a computational simulation to serve as a reference point for the simulation. Testing was conducted using liquid nitrogen as a cryogenic propellant simulant. A 1.06 cm diameter thin orifice with a rounded inlet was tested in an approximately 1.25 kg/s flow with inlet pressures ranging from 504.1 kPa to 829.3 kPa. Pressure fluctuations generated by the orifice were measured using a high frequency pressure sensor located 0.64 tube diameters downstream of the orifice. Fast Fourier Transforms were performed on the high frequency data to determine the instability frequency. Shedding resulted in a primary frequency with a cavitation related subharmonic frequency. For this experiment, the cavitation instability ranged from 153 Hz to 275 Hz. Additionally, the strength of the cavitation occur red as a function of cavitation number. At lower cavitation numbers, the strength of the cavitation instability ranged from 2.4 % to 7 % of the inlet pressure. However, at higher cavitation numbers, the strength of the cavitation instability ranged from 0.6 % to 1 % of the inlet pressure.

Hitt, Matthew A.; Lineberry, David M.; Ahuja, Vineet; Frederick, Robert A,

2012-01-01

308

Experimental investigation of supersonic flow over elliptic surface  

Science.gov (United States)

The coherent structures of flow over a compression elliptic surface are experimentally investigated in a supersonic low-noise wind tunnel at Mach Number 3 using nano-tracer planar laser scattering (NPLS) and particle image velocimetry (PIV) techniques. High spacial resolution images and the average velocity profiles of both laminar inflow and turbulent inflow over the testing model were captured. From statistically significant ensembles, spatial correlation analysis of both cases is performed to quantify the mean size and orientation of large structures. The results indicate that the mean structure is elliptical in shape and structure angles in separated region of laminar inflow are slightly smaller than that of turbulent inflow. Moreover, the structure angle of both cases increases with its distance away from from the wall. POD analysis of velocity and vorticity fields is performed for both cases. The energy portion of the first mode for the velocity data is much larger than that for the vorticity field. For vorticity decompositions, the contribution from the first mode for the laminar inflow is slightly larger than that for the turbulent inflow and the cumulative contributions for laminar inflow converges slightly faster than that for turbulent inflow

Zhang, Qinghu; Yi, Shihe; He, Lin; Zhu, Yangzhu; Chen, Zhi

2013-11-01

309

a Theoretical and Experimental Investigation of Annular Sector Microstrip Antennas  

Science.gov (United States)

An investigation from a theoretical and an experimental standpoint of a particular type of microstrip antenna having the shape of an annular sector is presented. The cavity model is used to evaluate the input impedance and radiation patterns of these antennas. Using the cavity model, fields radiated by the antenna are determined from a formulation that accounts for the possibility of surface and leaky waves. The performance of such antennas as a function of dielectric thickness and relative permittivity is examined. A simplified equivalent Resistor Inductor Capacitor (RLC) circuit that models the input impedance of the antennas is presented. The simplified model is shown to provide an extremely accurate representation of the antenna. It is shown that the component values are easily recognized from a measured admittance locus. Several techniques, which can be applied to a patch antenna of any shape, are developed for measuring the antenna's unloaded Q. Measurements are found to closely match theoretically predicted values. Effects of the ground plane on the radiated fields are discussed.

Weiss, Steven John

1995-01-01

310

Experimental investigation of nozzle/plume aerodynamics at hypersonic speeds  

Science.gov (United States)

Much of the work involved the Ames 16-Inch Shock Tunnel facility. The facility was reactivated and upgraded, a data acquisition system was configured and upgraded several times, several facility calibrations were performed and test entries with a wedge model with hydrogen injection and a full scramjet combustor model, with hydrogen injection, were performed. Extensive CFD modeling of the flow in the facility was done. This includes modeling of the unsteady flow in the driver and driven tubes and steady flow modeling of the nozzle flow. Other modeling efforts include simulations of non-equilibrium flows and turbulence, plasmas, light gas guns and the use of non-ideal gas equations of state. New experimental techniques to improve the performance of gas guns, shock tubes and tunnels and scramjet combustors were conceived and studied computationally. Ways to improve scramjet engine performance using steady and pulsed detonation waves were also studied computationally. A number of studies were performed on the operation of the ram accelerator, including investigations of in-tube gasdynamic heating and the use of high explosives to raise the velocity capability of the device.

Bogdanoff, David W.; Cambier, Jean-Luc; Papadopoulos, Perikles

1994-01-01

311

Experimental investigation of hardfaced martensitic steel under slurry abrasion conditions  

International Nuclear Information System (INIS)

Wear by slurry abrasion is a potential problem in engineering components subjected to particulate flow. The life of the components under slurry abrasive wear situations is primarily decided by operating conditions and the materials properties. Martensitic steels are widely used for abrasion resistant applications. The present work reports slurry abrasion response of hardfacing martensitic steel under a wide range of experimental conditions. The response data is generated using systematic and simultaneous variation of test parameters. The experiments were performed using silica sand slurry with different slurry concentration, particle size, sliding distance and load. The results of the investigation suggest that slurry concentration had relatively stronger effect than normal load. The wear volume loss exhibited an increasing trend with increasing severity of test parameters. An empirical equation is proposed to describe the interactive effect of the test parameters, abrasive particle properties and material property. SEM (Scanning Electron Microscope) studies revealed different morphology of the worn surfaces which was attributed to mild to severe slurry abrasion test conditions.

2010-09-01

312

Experimental investigations of the ''Angara-5'' facility module  

International Nuclear Information System (INIS)

The description and results of experimental investigation of the head module of the ''Angara-5'' facility are presented. The module represents and energy storage consisting of the Arkadiev-Marx generator and double shaping line (DSL). The intermediate DSL electrode is conneeted with the generator by two conductors passing through the separating section with four dielectric partitions. In the course of DSL commutation realized by five gass-filled commutators internal electrode charging is performed through the cantilever being isolation induction. Basic DSL characteristics are given. In the process of operation on increasing charge module voltage about 180 pulses with DSL charge voltage-1 MV, 80 pulses with charge voltage 1,6 MV and 10 pulses with 2,1 MV voltage have been performed. In all module operation conditions no break-down in water have been observed. Time spread of commutators switch on not exceeding +- 2,6 ns. Gas discharge channel losses are given. The module power balance under capacitor charging voltage +- 80 kV is presented

1981-06-23

313

Experimental investigation of design parameters on dry powder inhaler performance.  

Science.gov (United States)

The study aims to investigate the impact of various design parameters of a dry powder inhaler on the turbulence intensities generated and the performance of the dry powder inhaler. The flow fields and turbulence intensities in the dry powder inhaler are measured using particle image velocimetry (PIV) techniques. In vitro aerosolization and deposition a blend of budesonide and lactose are measured using an Andersen Cascade Impactor. Design parameters such as inhaler grid hole diameter, grid voidage and chamber length are considered. The experimental results reveal that the hole diameter on the grid has negligible impact on the turbulence intensity generated in the chamber. On the other hand, hole diameters smaller than a critical size can lead to performance degradation due to excessive particle-grid collisions. An increase in grid voidage can improve the inhaler performance but the effect diminishes at high grid voidage. An increase in the chamber length can enhance the turbulence intensity generated but also increases the powder adhesion on the inhaler wall. PMID:24055597

Ngoc, Nguyen Thi Quynh; Chang, Lusi; Jia, Xinli; Lau, Raymond

2013-11-30

314

STUDY OF X-RAY LASER SCHEMES USING NEW EXPERIMENTAL FACILITIES AT THE RUTHERFORD APPLETON LABORATORY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

New experimental facilities have recently been developed at the Rutherford Appleton Laboratory for line focus irradiation using the Vulcan Neodymium glass laser installation and for time-resolved spectroscopy of VUV emission. The system is designed for study of XUV lasers and has been used in a preliminary survey of several schemes. Particular emphasis has been placed on study of the CVI recombination laser using fibre targets of up to 2cm length. Measurements show clear evidence of amplifica...

Key, M.; Boon, J.; Brown, C.; Chenais-popovics, C.; Corbett, R.; Damerell, A.; Gottfeldt, P.; Hooker, C.; Kiehn, G.; Lewis, C.; Pepler, D.; Pert, G.; Reagan, C.; Rose, S.; Ross, I.

1986-01-01

315

Histological changes caused by experimental Riedeliella graciliflora (Leg. Papilionoideae) poisoning in cattle and laboratory animals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tissues from cattle, mice, rats and guinea pigs experimentally intoxicated by Riedeliella graciliflora were studied histologically. Cattle lymph nodes, spleen, Peyer patches and peribronchial lymphoid tissues had diffuse necrosis of lymphocytes, mainly in the germinal centers of the follicles. This lesion was less severe in laboratory animals. All species had severe enteritis with infiltration of the lamina propria by mononuclear cells. Some cells in this infiltrate were necrotic. Degeneratio...

2001-01-01

316

Experimental Investigation of Piston Rings for Internal Combustion Engines  

DEFF Research Database (Denmark)

One of the major prerequisites for calculating piston ring friction is a good description of the tribological situation. A very important condition for describing the frictional behavior of a piston ring correctly is knowledge about the amount of lubricant present. For piston rings the external load may be established by measuring the pressure distribution, i.e. the pressure drop in the piston ring package. Speed and temperature may also be established. The amount and distribution of oil present is, however, not easily determined. It is often assumed that it operates under fully flooded conditions, but this is not the case in real life operation. These problems forms the basis for the experimental investigation. In large two-stroke engines the cylinder oil is supplied to the bearing at discrete locations on the cylinder liner at a specific rate at a certain time. The shifting in lubrication regimes and the non-uniform oil distribution opens for the possibility of starved conditions for the piston ring bearing. Therefore it is important to measure the oil distribution on the liner as a function of the operating conditions. The amount of lubricant available is reflected in the friction absorbed in the bearing. The following properties are measured: Oil film thickness - along liner (axial variation), oil film thickness - along piston ring (circumferential variation), piston tilt, temperature of piston rings and liner, pressure at piston lands and forces on piston rod. Since the frictional forces are small compared to the rest of the acting forces the main design idea is to fix the piston, while the cylinder liner moves. This approach makes it simple to measure the parameters mentioned above by putting the instrumentation in the piston. The aim of this paper is describe the tribological condition between a piston ring and cylinder. A test apparatus is used to study the interaction between a piston ring and a cylinder liner. The piston ring experiences hydrodynamic, mixed and boundary lubrication and the squeeze effect of the piston ring is significant. Experimental results are presented and the influence from speed, number of piston rings, lubrication oil type and supply flow is discussed.

Christiansen, Jens; Klit, Peder

2007-01-01

317

Experimental investigation and mechanical modelling of zircaloy-4 stress corrosion cracking  

International Nuclear Information System (INIS)

In Pressurised Water Reactor fuel assemblies, cladding tubes constitute the first safety barriers against the fission product dissemination. It is therefore essential to ensure their integrity under all the reactor operating conditions. During an important loading, resulting from severe reactor power transients, clad failures can be induced by a Stress Corrosion Cracking phenomenon (SCC) due to the combined action of mechanical loading and gaseous fission products generated by the fuel pellets. The aim of our work is to study the role played by different parameters on the SCC phenomenon of Zircaloy-4 claddings. It is made up of three complementary parts: - the modelling of local mechanical fields applied during laboratory tests; - the design of specific SCC experiments to investigate the influence of several mechanical parameters; - the observation of the damage mechanisms occurring during these different experiments. Coupling mechanical modelling and laboratory tests allowed to obtain some local information which cannot be obtained experimentally. A hierarchical approach was then used to develop accurate constitutive laws of the stress-relieved Zircaloy-4 alloy. The constitutive equations derived from this approach were fitted to the mechanical loading applied during the experiments. The specific SCC tests results and SEM observations proved the existence of a time incubation period, which lasts for an important part of the lifetime measured in the SCC pressurization tests. This incubation period is closely related to the experimental conditions of the laboratory tests. However the incubation period must be distinguished from the actual SCC mechanisms and corresponds to the time required for the metal surface to strip of its oxide layer by mechanical cracking and/or attack of zircon. First results obtained on pre-cracked samples showed that this stage, which introduces an artefact in the experimental test analysis, can be suppressed. Moreover, we have borne out that initiation and propagation of SCC cracks can be very fast when metal is laid bare and when iodine is present. (author)

2001-01-01

318

Inquiry-based Investigation in Biology Laboratories: Does Neem Provide Bioprotection against Bean Beetles?  

Science.gov (United States)

We developed an inquiry-based biology laboratory exercise in which undergraduate students designed experiments addressing whether material from the neem tree ("Azadirachta indica") altered bean beetle ("Callosobruchus maculatus") movements and oviposition. Students were introduced to the bean beetle life cycle, experimental

Pearce, Amy R.; Sale, Amanda Lovelace; Srivatsan, Malathi; Beck, Christopher W.; Blumer, Lawrence S.; Grippo, Anne A.

2013-01-01

319

Horonobe Underground Research Laboratory project. Investigation report for the 2006 fiscal year  

International Nuclear Information System (INIS)

The Horonobe Underground Research Laboratory is planned to extend over a period of 20 years. The investigations will be conducted in three phases, namely 'Phase 1: Surface-based investigations', 'Phase 2: Construction Phase' (investigations during construction of the underground facilities) and 'Phase 3: Operation phase' (research in the underground facilities). This report summarizes the results of the investigations for the 2006 fiscal year (2006/2007), the second year of the Phase 2 investigations. The investigations, which are composed of 'Geoscientific research' and 'R and D on the geological disposal of high-level radioactive waste (HLW)', were carried out according to 'Horonobe Underground Research Laboratory Project Investigation Program for the 2006 Fiscal Year'. The results of these investigations, along with the results which were obtained in other departments of Japan Atomic Energy Agency (JAEA), are properly offered to the implementations and the safety regulations. JAEA proceeded with the project in, collaboration with experts from domestic and overseas research organisation. (author)

2008-01-01

320

Horonobe Underground Research Laboratory project investigation report for the 2008 fiscal year  

International Nuclear Information System (INIS)

The Horonobe Underground Research Laboratory Project is planned to extend over a period 20 years. The investigations will be conducted in three phases, namely 'Phase 1: Surface-based investigations' 'Phase 2: Construction Phase' (investigations during construction of the underground facilities) and 'Phase 3: Operation phase' (research in the underground facilities). This report summarizes the results of the investigations for the 2008 fiscal year (2008/2009), the 4th year of the Phase 2 investigations. The investigations, which are composed of 'Geoscientific research' and 'R and D on geological disposal technology', were carried out according to 'Horonobe Underground Research Laboratory Project Investigation Program for the 2008 Fiscal year'. The results of these investigations, along with the results which were obtained in other departments of Japan Atomic Energy Agency (JAEA), are properly offered to the implementations and the safety regulations. For the sake of this, JAEA has proceeded with the project in collaboration with experts from domestic and overseas research organisations. (author)

2009-01-01

 
 
 
 
321

Combined experimental and computational investigation of sterile air flows in surgical environments  

Science.gov (United States)

Surgical environments in hospitals utilize downward, low-turbulence, sterile air flow across the patient to inhibit transmission of infectious diseases to the surgical site. Full-scale laboratory experiments using particle image velocimetry were conducted to investigate the air distribution above the patient area. Computational fluid dynamics models were developed to further investigate the air distribution within the operating room in order to determine the impact of ventilation design of airborne infectious disease pathways. Both Reynolds-averaged Navier-Stokes equations and large eddy simulation techniques are currently being used in the computational modeling to study the effect of turbulence modeling on the indoor air distribution. CFD models are being calibrated based on the experimental data and will be used to study the probability of infectious particles entering the sterile region of the room.

McNeill, James; Hertzberg, Jean; Zhai, Zhiqiang

2010-11-01

322

Experimental Investigation on the Melt Pool Configuration with the COSMOS  

International Nuclear Information System (INIS)

In general, a two-layer melt pool with a light metallic layer of Fe-Zr on top of oxidic pool was assumed to be a bounding melt configuration in the safety analyses for the severe accidents. The experimental results of the OECD MASCA, however, have shown that when a sufficient amount of non-oxidized zirconium (Zr) is available, then metallic uranium (U) migrates to the metallic layer. The transfer of species between the U, O, Zr melt and the steel can result in a significant density increase of the metallic phase. The density increase of the metallic phase can lead to inverse stratification with an additional heavy metal layer below the oxidic pool. The presence of the metallic layer at the bottom of the lower head is likely to decrease the thickness of the top metallic layer and consequently to increase the risk of the focusing effect. At KAERI, thermodynamic analyses using the GEMINI code were performed to examine the final melt pool configuration during the severe accidents in the APR1400. In this study, based on the thermodynamic analysis results, for an investigation on the molten pool configurations considering the layer inversion of the heavy metallic layer, a series of test, named as the COSMOS (Corium configuration of the molten State in the Most Severe Accidents), are in progress. Since the melt pool configurations were different in the representative accident sequences of the APR1400, a series of test will be performed for the initial melt pool conditions of the major severe accident sequences of the APR1400

2011-10-01

323

Volcanic ash aggregation: experimental, field and theoretical investigations  

Science.gov (United States)

Particle aggregation is considered as a key process that may affect dispersal and sedimentation of volcanic ash, with significant implications for the associated hazards. Most theoretical studies of particle aggregation have been based on the Smoluchowski Coagulation Equation (SCE), which describes the expected time evolution of the total grain-size distribution under the hypothesis that particles can collide and stick together following specific mathematical relations (kernels). Unfortunately these kernels are not very well understood and quantified. In particular, the probability of sticking is almost completely unknown and it can be described theoretically just in a very approximate way. We have carried out a set of experiments to investigate how the sticking efficiency varies as a function of particle size and velocity. Ash particles larger than 100 micron were suspended in a 4-meters high vertical wind tunnel and recorded in time with a high-speed camera. Filming the interactions of small particles and using a dedicated Particle Tracking Velocimetry software, sticking efficiencies were characterized based on the number of particles that formed aggregates in relation to the number of collisions. Experiments were repeated in order to have a good statistical significance and to cover different environmental conditions (temperature and humidity). We have also carried out field experiments during various eruptions at Sakurajima volcano (Japan) for the characterization of aggregates in situ in combination with high speed recordings and SEM studies. Experimental and field results were then merged with the theoretical framework (SCE) to study the time evolution of different initial grain-size distributions for different external conditions.

Rossi, Eduardo; Bagheri, Gholamhossein; Biasse, Sébastien; Bonadonna, Costanza; Falcone, Jean-Luc; Chopard, Bastien; Pontelandolfo, Piero; Haas, Patrick

2014-05-01

324

Experimental Investigation of Organic Synthesis in Hydrothermal Environments  

Science.gov (United States)

Seafloor hydrothermal systems may be the most likely locations on the early Earth for the emergence of life. Because of the disequilibrium inherent in such dynamic, mixing environments, abundant chemical energy would have been available for formation of the building blocks of life. In addition, theoretical studies suggest that organic compounds in these conditions would reach metastable states, due to kinetic barriers to the formation of stable equilibrium products (CO2 and methane). The speciation of organic carbon in metastable states is highly dependent on the oxidation state, pH, temperature, pressure and bulk composition of the system. The goal of our research is to investigate the effects of a number external variables on the formation, transformation, and stability of organic compounds at hydrothermal conditions. We have begun experimental work to attempt to control the oxidation state of simulated hydrothermal systems by using buffers composed of mineral powders and gas mixtures. We are also beginning to test the stability of organic compounds under these conditions. The experiments are being performed using the hydrothermal bomb apparatus at the U.S. Geological Survey in Menlo Park, CA and the supercritical water oxidizer (SCWO) at NASA Ames Research Center in Moffet Field, CA. The amino acids decomposed rapidly. Even after the approximately 15 minutes between addition of the amino acids and the first sampling, no amino acids were detected in the PPM system by GC- MS, while in the FeFeO system the amino acids were present at a level of less than 50% of original. Carboxylic acids, ammonia, and CO2 were the main products, along with some unidentified compounds. The ratios of carboxylic acids and concentrations of other products seem to have remained stable during the experiments, consistent with observations of other metastable systems and theoretical predictions.

Shock, Everett L.

1998-01-01

325

Experimental investigation and modeling of diamond nucleation on silica substrates  

Science.gov (United States)

Thin films created using chemical vapor deposition (CVD) have numerous applications. In order for these films to function effectively it is often necessary to better control their properties. This can be accomplished through a more thorough understanding of the initial stages of a film's growth. At this stage, when nucleation occurs, the microstructure of a film is determined and this has a significant influence on its properties. Two materials which are currently grown using CVD are diamond and silicon nitride. In this research, an investigation of the nucleation of both of these materials is conducted. Deposition of diamond was carried out with a microwave plasma system, while silicon nitride was nucleated using an impinging-jet reactor. Several characterization techniques were employed, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), parallel electron energy loss spectroscopy (PEELS) and optical emission spectroscopy (OES). The primary focus of the work was on diamond nucleation. Deposition was conducted on three different substrates, including silicon, oxidized silicon and silica. Several differences in experimental results were observed between the substrates. In order to explain these variations a kinetic model was developed which considers the influence of the substrate on the local gas phase chemistry. The model reveals that the concentration of oxygen is greater near silica substrates. TEM and PEELS show the presence of amorphous carbon islands on silica substrates after a pretreatment step. It is probable that these serve as nucleation sites for crystalline diamond. An additional kinetic model was developed which considers the islands as mixtures of spsp2 and spsp3 carbon. It was found that the lower surface energy of graphite and higher supersaturation ratio of diamond lead to an enhancement of nucleation. Silicon nitride was deposited on an interlayer that was found to consist of amorphous silicon nitride and crystalline silicon. The structure of the interlayer changed as it was deposited until eventually nucleation of crystalline Sisb3Nsb4 became favorable.

Koritala, Rachel Elizabeth

1997-08-01

326

Experimental Investigations of Cavitation Dynamics and Cavitation Noise.  

Science.gov (United States)

In this paper some of the research and development work on cavitation noise at the Swedish State Shipbuilding Experimental tank (SSPA) is described. This work is at SSPA mainly experimental and here two projects are described in detail. One of these proje...

G. Bark W. B. Van Berlekom

1979-01-01

327

Neutron Elastic Scattering Cross Sections Experimental Data and Optical Model Cross Section Calculations. A Compilation of Neutron Data from the Studsvik Neutron Physics Laboratory  

International Nuclear Information System (INIS)

Neutron elastic scattering cross section measurements have been going on for a long period at the Studsvik Van de Graaff laboratory. The cross sections of a range of elements have been investigated in the energy interval 1.5 to 8 MeV. The experimental data have been compared with cross sections calculated with the optical model when using a local nuclear potential

1969-01-01

328

Neutron Elastic Scattering Cross Sections Experimental Data and Optical Model Cross Section Calculations. A Compilation of Neutron Data from the Studsvik Neutron Physics Laboratory  

Energy Technology Data Exchange (ETDEWEB)

Neutron elastic scattering cross section measurements have been going on for a long period at the Studsvik Van de Graaff laboratory. The cross sections of a range of elements have been investigated in the energy interval 1.5 to 8 MeV. The experimental data have been compared with cross sections calculated with the optical model when using a local nuclear potential.

Holmqvist, B.; Wiedling, T.

1969-06-15

329

Horonobe Underground Research Laboratory project. Investigation report for the 2011 fiscal year  

International Nuclear Information System (INIS)

The Horonobe Underground Research Laboratory Project is planned to extend over a period 20 years. The investigations will be conducted in three phases, namely “Phase 1: Surface-based investigations”, “Phase 2: Construction Phase” (investigations during construction of the underground facilities) and “Phase 3: Operation phase” (research in the underground facilities). This report summarizes the results of the investigations for the 2011 fiscal year (2011/2012). The investigations, which are composed of “Geoscientific research” and “R and D on geological disposal technology”, were carried out according to “Horonobe Underground Research Laboratory Project Investigation Program for the 2011 Fiscal year”. The results of these investigations, along with the results which were obtained in other departments of Japan Atomic Energy Agency (JAEA), are properly offered to the implementations and the safety regulations. For the sake of this, JAEA has proceeded with the project in collaboration with experts from domestic and overseas research organisations. (author)

2012-01-01

330

Horonobe Underground Research Laboratory project. Investigation report for the 2010 fiscal year  

International Nuclear Information System (INIS)

The Horonobe Underground Research Laboratory Project is planned to extend over a period 20 years. The investigations will be conducted in three phases, namely 'Phase 1: Surface-based investigations', 'Phase 2: Construction Phase' (investigations during construction of the underground facilities) and 'Phase 3: Operation phase' (research in the underground facilities). This report summarizes the results of the investigations for the 2010 fiscal year (2010/2011). The investigations, which are composed of 'Geoscientific research' and 'R and D on geological disposal technology', were carried out according to 'Horonobe Underground Research Laboratory Project Investigation Program for the 2010 Fiscal year'. The results of these investigations, along with the results which were obtained in other departments of Japan Atomic Energy Agency (JAEA), are properly offered to the implementations and the safety regulations. For the sake of this, JAEA has proceeded with the project in collaboration with experts from domestic and overseas research organisations. (author)

2011-01-01

331

Aespoe Hard Rock Laboratory. Overview of the investigations 1986-1990  

International Nuclear Information System (INIS)

In order to prepare for the siting and licensing of a spent fuel repository SKB has decided to construct a new underground research laboratory. The pre-investigations for the Aespoe Hard Rock Laboratory started in late 1986. This report gives a comprehensive compilation of the different investigations performed during the pre-investigation phase (1986-1990). The information is mainly compiled in CAD-generated maps and illustrations in which the reader can gather information concerning the scope of work as well as references to more detailed reports for further study. (au)

1991-01-01

332

Experimental investigation of Ca isotopic fractionation during abiotic gypsum precipitation  

Science.gov (United States)

Experiments investigating Ca isotopic fractionation during gypsum precipitation were undertaken in order to elucidate the mechanisms and conditions that govern isotopic fractionation during mineral precipitation. Both stirred and unstirred free drift gypsum precipitation experiments were conducted at constant initial ionic strength (0.6 M) and variable initial saturation states (4.8-1.5) and Ca2+:SO42- ratios (3 and 0.33). Experimental durations varied between 0.5 and 190 h, while temperature (25.9-24.0 °C), pH (5.8-5.4) and ionic strength (0.6-0.5) were relatively constant. In all experiments, 20-80% of the initial dissolved Ca reservoir was precipitated. Isotopically light Ca preferentially partitioned into the precipitated gypsum; the effective isotopic fractionation factor (?44/40Cas-f = ?44/40Casolid - ?44/40Cafluid) of the experimental gypsum ranged from -2.25‰ to -0.82‰. The log weight-averaged, surface area normalized precipitation rates correlated with saturation state and varied between 4.6 and 2.0 ?mol/m2/h. The crystal size and aspect ratios, determined by SEM images, BET surface area, and particle size measurements, co-varied with precipitation rate, such that fast growth produced small (10-20 ?m), tabular crystals and slow growth produced larger (>1000 ?m), needle shaped crystals. Mass balance derived ?44Cas and ?44Cas-f, calculated using the initial fluid ?44Ca and the mass fraction of Ca removed during precipitation (fCa) as constraints, suggest that the precipitate was not always sampled homogeneously due to the need to preserve the sample for SEM, surface area, and particle size analyses. The fractionation factor (?s-f), derived from Rayleigh model fits to the fluid and calculated bulk solid, ranged from 0.9985 to 0.9988 in stirred experiments and 0.9987 to 0.9992 in unstirred experiments. The ?s-f demonstrated no clear dependence on either precipitation rate or initial saturation state in stirred reactors, but exhibited a positive dependence on rate in unstirred experiments. The differences in ?s-f between stirred and unstirred reactors, as well as a general correlation between ?s-f and crystal morphology, led us to hypothesize that growth on different crystal faces controls the isotopic composition of gypsum. We also explore the idea that speciation in solution explains the difference between experiments in which the only major difference was the Ca2+ to SO42- ratio in solution. The importance of understanding the environmental controls on the fractionation factor during mineral precipitation is highlighted in this study. The fractionation factor of gypsum precipitation near chemical equilibrium was found to be ?0.9995, rather than 1, indicating that even at near equilibrium conditions, the ?44Ca of minerals are not likely to record the ?44Ca of the solution directly. However, the measurable isotopic fractionation associated with gypsum formation does suggest that a gypsum-based proxy may be useful in constraining Ca cycling in marginal environments over geologic time scales. Model examples are provided that demonstrate how such a proxy would operate.

Harouaka, Khadouja; Eisenhauer, Anton; Fantle, Matthew S.

2014-03-01

333

EXPERIMENTAL INVESTIGATION OF DEFROST USING WARM LIQUID REFRIGERANT  

Science.gov (United States)

This paper reports the results from laboratory tests of a low-temperature supermarket refrigeration system with two open and two reach-in display cases. Tests were performed at condensing temperatures ranging from 10 to 40 C and at an evaporating temperature of -34 C. The perfo...

334

The experimental investigation of exotic nuclei properties in Dubna  

International Nuclear Information System (INIS)

The present work presents the results of research with radioactive beams carried out at FLNR JINR and in collaboration with other scientific centers. Exotic states of nuclei are being studied at the Flerov Laboratory of Nuclear Reactions with the use of beams of heavy ions in the 5 MeV/A?E?100 MeV/A range

1995-05-29

335

Experimental investigation of gas storage properties of black shales  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In exploration for shale gas, reliable estimations of Gas-In-Place (GIP) and portion of technically recoverable resource pose a challenging task. Improvement of our understanding of gas stogare capacity of carbonaceous shales and its evolution during geological history requires carefully designed experiments to obtain reliable experimental data. Moreover, the experimental conditions have to cover a range representative of the in-situ reservoir conditions. This thesis, which was conducted duri...

Gasparik, Matus

2013-01-01

336

A laboratory for investigating and monitoring the contamination of air with radioactive iodine  

International Nuclear Information System (INIS)

The paper describes a model of an isotope laboratory of 2nd class called ''A laboratory for investigating and monitoring the contamination of the air with radioactive iodine'' based on the laboratory apparatus produced in Poland and electronic apparatus manufactured by ZZUJ POLON. The scope of work and working procedures for "1"3"1I and CH_3"1"3"1I vapour generators are described. The determination of the efficiency of fiber filters and adsorption materials is also presented. The radiation hazard from the "1"3"1I sources during work and during a radiation accident is evaluated. (author)

1978-01-01

337

Experimental Investigation and Analysis of HEC-6 River Morphological Model  

Science.gov (United States)

Only comparatively few experimental studies have been carried out to investigate the performance of the HEC-6 river morphological model. The model was developed by the Hydrologic Engineering Center of the US Army Corps of Engineers. In this study, experiments were carried out in a 20 m long concrete flume 0.6 m wide with varying rectangular cross-sections. The channel bed is paved with uniform sand of D50 = 0.9 mm and D90 = 1.2 mm within the test reach of 12 m. Two types of experiments were carried out with sediment transport, one under steady uniform flow and another under steady non-uniform flow conditions. Nine steady uniform flow experiments were carried out to compare the measured equilibrium relationship of flow and sediment transport rate with two bedload formulae, namely, Du Boys and Meyer-Peter and Muller, and with three total load formulae, namely, Toffaleti, Laursen and Yang. It was found that even though the sediment transport consists of a certain portion of bedload, the total load formulae give satisfactory results and better agreement than the two bedload formulae. Five steady non-uniform flow experiments were carried out under various conditions of varying bed profile and channel width and also with sediment addition and withdrawal. The measured transient water surface and bed profiles are compared with the computed results from the HEC-6 model. It was found that the Toffaleti and Yang total load formulae used in the HEC-6 model give the most satisfactory prediction of actual bed profiles under various conditions of non-uniform flow and sediment transport. The effects of Manning's n, variations of sediment inflow, various sediment transport formulae, sediment grain size and the model numerical parameters, i.e. distance interval x and numerical weighting factor, on the computed water surface and bed profiles were determined. It was found that the selection of the sediment transport formulae has the most significant effect on the computed results. It can be concluded that the HEC-6 model can predict satisfactorily a long-term average pattern of local scour and deposition along a channel with either a small abrupt change in geometry or gradually varying cross-sections. However, the accuracy of the model prediction is reduced in the regions where highly non-uniform flow occurs.

Tingsanchali, Tawatchai; Supharatid, Seree

1996-05-01

338

Numerical and experimental investigation of a rockfall drapery system  

Science.gov (United States)

Rockfalls represent a significant hazard to people and infrastructures in steep terrain, should it be a mountainous region, a quarry, or a mine. Although rockfall occurrences cannot be totally eliminated, it is possible to reduce the risk by deploying effective rockfall protective systems such as metallic wire mesh draperies. This work focuses on the performance of a simple drapery system with a double-twisted hexagonal wire mesh. Numerical modelling and experimental investigations have been performed. The main objective of the work is the residual hazard assessment in conjunction with such a system since blocks can still detach between the installed drapery and the rock surface. First, the numerical model for the drapery mesh and the rock slope is presented. Following the approach by Bertrand et al. [1], a discrete element model of a hexagonal wire mesh has been implemented into the open-source framework YADE [4]. The mesh is discretised by a set of spherical particles which interact remotely (i.e. interactions between the particles exist without direct contact) and are located at the physical nodes of the mesh. The rock slope is represented by triangular elements which have been generated on the basis of a point cloud representation of the rock slope. The slope is assumed to be rigid and energy dissipation on the slope during rock impact is considered via friction and viscous damping. Second, results of field tests carried out at a mine in New South Wales (Australia) are presented [3]. Concrete blocks with shapes according to EOTA [2] were released from the top of a highwall. The tests were carried out on two different sections of the highwall: the first section had a drapery system installed whereas the second section had no protective system installed. In the first section, the blocks were released between the rock surface and the mesh drapery. The 3D block trajectories were recorded by using two stereo pairs of synchronised high speed cameras. The collected data has then been used to calibrate and validate the numerical model. Finally, some remarks on the final residual hazard assessment will be given by showing some capabilities of the developed numerical model. Acknowledgments: The authors gratefully acknowledge the financial support of the Australian Coal Association Research Program (ACARP).

Thoeni, K.; Giacomini, A.; Lambert, C.; Sloan, S. W.

2012-04-01

339

Anaesthesia and post-operative analgesia following experimental surgery in laboratory rodents: are we making progress?  

Science.gov (United States)

Current attitudes to the use of animals in biomedical research require that any pain or distress should be minimised. This can often be achieved by the use of appropriate anaesthetic and analgesic regimens. There, is however, little information on the peri-operative regimens used. A literature review was conducted to estimate how commonly analgesics are administered to laboratory rodents, the most widely used species of laboratory animals, and to assess the anaesthetic regimens employed. Studies describing potentially painful experimental procedures involving rodents were identified from peer-reviewed journals published from 1990 to 1992 and from 2000 to 2002. In papers published between 2000 and 2002, if analgesic administration was not specified, the institutional veterinary surgeons or authors of the papers were contacted by e-mail to obtain additional information on analgesic use. From 1992 to 2002, there was an increase in the reported prevalence of analgesic administration to laboratory rodents from 2.7% to 19.8%. Although the use of analgesics has increased over the past ten years, the overall level of post-operative pain relief for laboratory rodents is still low. Anaesthetic methodology changed markedly between the two time-periods sampled. Notably, there was an increase in the use of isoflurane and of injectable anaesthetic combinations such as ketamine/xylazine, whereas the use of ether and methoxyflurane decreased. PMID:16180987

Richardson, Claire A; Flecknell, Paul A

2005-04-01

340

Study on clinical and laboratory diagnostic of Lyme disease in dogs after experimental infection  

Directory of Open Access Journals (Sweden)

Full Text Available Experimental infection was done on 13 dogs, with B. burgdorferi s.l., in the epitzootiological area where Lyme disease in dogs and humans is present. Prior to the experimental infection, dogs in the experiment had no contact with B. burgdorferi, and they were kept in isolation. Serological methods used in the study were complement fixation and ELISA test. Biochemical blood analysis was done, also. The experimental infection of dogs was done with a referent ATCC B. burgdorferi s.l. culture, and with the isolates of B. burgdorferi s.l. previousely gained from Ixodes ricinus ticks collected on selected locations of the observed region in the northern part of Serbia (Vojvodina province. After the experimental infection, clinical symptoms were not seen in dogs and positive serological results were found in 70% of experimentally infected dogs. Immunodiagnostic criteria for the diagnosis of Lyme disease in dogs are established. In dogs without clinical symptoms for Lyme disease, when clarifying the laboratory results, one must have in mind the epizootiological situation of the region and also the possibility of former contact of the dog with B. burgdorferi s.l. For epizootiological surveys, CF can be used as an approximate screening method, with obligatory conformation with ELISA in the case of positive findings.

Savi? Sara

2012-01-01

 
 
 
 
341

Using experimental design modules for process characterization in manufacturing/materials processes laboratories  

Science.gov (United States)

Modules dealing with statistical experimental design (SED), process modeling and improvement, and response surface methods have been developed and tested in two laboratory courses. One course was a manufacturing processes course in Mechanical Engineering and the other course was a materials processing course in Materials Science and Engineering. Each module is used as an 'experiment' in the course with the intent that subsequent course experiments will use SED methods for analysis and interpretation of data. Evaluation of the modules' effectiveness has been done by both survey questionnaires and inclusion of the module methodology in course examination questions. Results of the evaluation have been very positive. Those evaluation results and details of the modules' content and implementation are presented. The modules represent an important component for updating laboratory instruction and to provide training in quality for improved engineering practice.

Ankenman, Bruce; Ermer, Donald; Clum, James A.

1994-01-01

342

Susceptibility of laboratory and domestic animals to experimental infection with Potiskum virus.  

Science.gov (United States)

The biological characteristics of Potiskum virus, a hitherto undescribed virus isolated in Nigeria from the liver of a giant rat (Cricetomys gambianus), were studied by experimental infections of laboratory and domestic animals. The laboratory animal hosts used included mice, rats, rabbits and chicks. Suckling and weaning mice succumbed to fatal infection when infected with Potiskum virus by intracerebral or intraperitoneal routes. Infected mice had high titres of virus and mild histopathological lesions which were confined to the brain. Chicks also developed a fatal disease following subcutaneous or oral infections with Potiskum virus. In contrast, albino rats and rabbits failed to succumb to overt disease by subcutaneous and intraperitoneal routes of inoculation. Albino rats did not develop antibody but rabbits developed haemagglutination inhibiting, neutralising and complement fixing antibodies. PMID:2558278

Omilabu, S A; Fagbami, A H; Olaleye, O D

1989-01-01

343

An Experimental Investigation of the Scaling of Columnar Joints  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Columnar jointing is a fracture pattern common in igneous rocks in which cracks self-organize into a roughly hexagonal arrangement, leaving behind an ordered colonnade. We report observations of columnar jointing in a laboratory analog system, desiccated corn starch slurries. Using measurements of moisture density, evaporation rates, and fracture advance rates as evidence, we suggest an advective-diffusive system is responsible for the rough scaling behavior of columnar join...

Goehring, Lucas; Lin, Zhenquan; Morris, Stephen W.

2006-01-01

344

Experimental investigation of an advanced adsorption refrigeration cycle  

Energy Technology Data Exchange (ETDEWEB)

Experimental measurements are made for a silica gel-water advanced absorption refrigeration chiller (1.2-kW [4,095-Btu/h] cooling capacity) to evaluate its performance under different temperature and adsorption/desorption cycle time conditions. This paper describes the operating principle of the chiller, outlines the experimental hardware, and discusses results obtained by varying the cooling and hot water inlet temperatures and adsorption/desorption cycle times, as well as their agreement with the simulated results given by a lumped parameter model. The chiller performance is analyzed in terms of cooling capacity and coefficient of performance (COP). Excellent qualitative agreement was obtained between the experimental data and simulated results. The results showed the advanced three-stage cycle to be particularly well suited for operation with low-grade-temperature waste heat as the driving source, since it worked with small regenerating temperature lifts (heat source-heat sink temperature) of 10 to 30 K.

Saha, B.B.; Kashiwagi, Takao [Tokyo Univ. of Agriculture and Technology (Japan). Mechanical Systems Engineering Dept.

1997-12-31

345

Confined granular flow in silos experimental and numerical investigations  

CERN Document Server

  During confined flow of bulk solids in silos some characteristic phenomena can be created, such as: —         sudden and significant increase of wall stresses, —         different flow patterns, —         formation and propagation of wall and interior shear zones, —         fluctuation of pressures and, —         strong autogenous dynamic effects. These phenomena have not been described or explained in detail yet. The main intention of the experimental and theoretical research presented in this book is to explain the above mentioned phenomena in granular bulk solids and to describe them with numerical FE models verified by experimental results.

Tejchman, Jacek

2013-01-01

346

Experimental Investigation of Aerodynamic Instability of Iced Bridge Cable Sections  

DEFF Research Database (Denmark)

The accretion of ice on structural bridge cables changes the aerodynamic conditions of the surface and influences hence the acting wind load process. Full-scale monitoring indicates that light precipitation at moderate low temperatures between zero and -5°C may lead to large amplitude vibrations of bridge cables under wind action. This paper describes the experimental simulation of ice accretion on a real bridge cable sheet HDPE tube segment (diameter 160mm) and its effect on the aerodynamic load. Furthermore, aerodynamic instability will be estimated with quasi-steady theory using the determined load coefficients and experimental simulation on a 1DOF elastically suspended cable section.

Koss, Holger; Lund, Mia Schou Møller

2013-01-01

347

A laboratory based experimental study of mercury emission from contaminated soils in the River Idrijca catchment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Results obtained by a laboratory flux measurement system (LFMS) focused on investigating the kinetics of the mercury emission flux (MEF) from contaminated soils of the Idrija Hg-mine region, Slovenia are presented. Representative soil samples with respect to total Hg concentrations (4–417 ?g g?1) and land cover (forest, meadow and alluvial soil) alongside the River Idrijca were analysed to determine the variation in MEF versus distance from the source, regula...

Kocman, D.; Horvat, M.

2010-01-01

348

A laboratory based experimental study of mercury emission from contaminated soils in the River Idrijca catchment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Results obtained by a laboratory flux measurement system (LFMS) focused on investigating the kinetics of the mercury emission flux (MEF) from contaminated soils of the Idrija Hg-mine region, Slovenia are presented. Representative soil samples with respect to total Hg concentrations (4–417 ?g g?1) and land cover (forest, meadow and alluvial soil) alongside the River Idrijca were analysed to determine the variation in MEF versus distance from the source, regulati...

Kocman, D.; Horvat, M.

2009-01-01

349

Experimental investigation of the formation and propagation of plasma jets created by a power laser: application to laboratory astrophysics; Etude experimentale de la formation et de la propagation de jets de plasma crees par un laser de puissance: application a l'astrophysique de laboratoire  

Energy Technology Data Exchange (ETDEWEB)

Plasma jets are often observed in the polar regions of Young Stellar Objects (YSO). For a better understanding of the whole processes at the origin of their formation and evolution, this research thesis aims at demonstrating the feasibility of a plasma jet generation by a power laser, and at investigating its characteristics. After a detailed description of Young Stellar Objects jets and an overview of theoretical models, the author describes some experiments performed with gas guns, pulsed machines and power lasers. He describes means of generation of a jet by laser interaction via strong shock propagation. He reports experimental work, describing the target, laser operating conditions and the determination of jet parameters: speed, temperature, density. Then, he introduces results obtained for plasma jet propagation in vacuum, describes their evolution with respect to initial conditions (target type, laser operating conditions), and identifies optimal conditions for generating a jet similar to that in astrophysical conditions. He considers their propagation in ambient medium like for YSO jets in interstellar medium. Two distinct cases are investigated: collision of two successive shocks in a gaseous medium, and propagation of a plasma jet in a gas jet.

Loupias, B

2008-10-15

350

Experimental investigation of vibroactivity of turbomachinery shaft seals  

Energy Technology Data Exchange (ETDEWEB)

Results of an experimental determination of the boundaries of stability and characteristics of rotor self-oscillations in rigid bearing supports with different types of seals (slot, labyrinth; honeycomb, and screw seals) and media to be sealed (air, mineral oil) are presented.

Bondarenko, G.A.; Pshik, V.R.

1982-04-01

351

An investigation to the Xinjiang experimental infrasonic stations  

International Nuclear Information System (INIS)

It presents the compassion of infrasonic stations for Comprehensive Nuclear-Test-Ban Treaty (CTBT) located in nearby Urumqi and analysis of recorded data. By a preliminary analysis, the experimental infrasonic stations have a fairly good monitoring capability that can detect not only atmospheric signals but also the ground explosive events. (authors)

2010-09-01

352

Making Controlled Experimentation More Informative in Inquiry Investigations  

Science.gov (United States)

This dissertation incorporates three studies that examine how the design of inquiry based science instruction, dynamic visualizations, and guidance for experimentation contribute to physics students' understanding of science. I designed a week-long, technology-enhanced inquiry module on car collisions that logs students' interactions with a…

McElhaney, Kevin Wei Hong

2010-01-01

353

a Theoretical and Experimental Investigation of Enhanced Internal Reflection.  

Science.gov (United States)

Internal reflection from the interface between a transparent incident region and a region with gain is examined theoretically and experimentally. The gain, related to population inversion, is established by optical excitation. A Beer's Law absorption of the pump beam produces a gain which decreases exponentially with distance from the interface. Infinite series solutions to the wave equations are derived in the gain region. The solutions are composed of two parts: one represents a wave traveling toward the interface, the other a wave traveling away from the interface. Theoretical values of the reflectance and incident angle are presented. Reflectances less than unity occur for incident angles near normal incidence. A maximum greater than unity, is reached in the vicinity of critical angle. As the incident angle is increased toward grazing incidence, the reflectance decreases toward unity. Singularities may occur in the amplitude reflectance coefficient for certain combinations of incident angle and gain region thickness. The angular width of the reflectance curve as a singularity is approached is extremely narrow (less than .01(DEGREES)). These singularities are considered non-physical and a consequence of the assumption that the gain coefficient is independent of the amount of energy removed from the gain region by the transmitted wave. This assumption is violated in the rate instances where the reflectance becomes extremely large (greater than 200 for the experimental case described). An experiment designed to observe and measure the reflectance from an optically excited laser dye is described. Experimental parameters are discussed. The method by which the data were acquired is described and the data are interpreted. The theoretical reflectance curves are appropriately averaged to account for incident beam divergence and fluctuations of certain experimental parameters. Experimental data are shown to be in favorable agreement with theory, in particular the angular position of the maximum reflectance and the magnitude of reflectance on either side of the maximum. It is concluded that the exponentially decreasing gain model is a good description for the gain region of the experiment.

Cybulski, Raymond Francis, Jr.

354

Facts and Figuring: An Experimental Investigation of Network Structure and Performance in Information and Solution Spaces  

CERN Document Server

Using data from a large laboratory experiment on problem solving in which we varied the structure of 16-person networks we investigate how an organization's network structure may be constructed to optimize performance in complex problem-solving tasks. Problem solving involves both search for information and search for theories to make sense of that information. We show that the effect of network structure is opposite for these two equally important forms of search. Dense clustering encourages members of a network to generate more diverse information, but it also has the power to discourage the generation of diverse theories: clustering promotes exploration in information space, but decreases exploration in solution space. Previous research, tending to focus on only one of those two spaces, had produced inconsistent conclusions about the value of network clustering. By adopting an experimental platform on which information was measured separately from solutions, we were able to reconcile past contradictions an...

Shore, Jesse; Lazer, David

2014-01-01

355

Experimental methods for investigations on internal fuel rod chemistry of light water reactor fuels  

International Nuclear Information System (INIS)

For studies in fuel rod internal chemistry special experimental procedures are needed in order to obtain results which are of real value for the improvement of knowledge in this field. Some investigation techniques are described which have been developed in KWU radiochemistry and fuel development laboratories. A part of them is directed towards the determination of migration and distribution of fission products (especially Cs and I) in LWR fuel. With heating experiments of mock-up materials radiotracers or short-term irradiations are used and fission product distribution is measured by micro ? scanning. From spent fuels microsamples are taken at definite locations; analysis is performed by ? spectrometry and neutron activation analysis. Fission product escape from defective fuel rods during power reactor operation is studied by radiochemical coolant analysis. Finally, O/M ratio of spent oxide fuel is analyzed by controlled-potential coulometry. (orig.)

1981-03-01

356

A Laboratory-Based Investigation on Biodegradation and Bioremediation of Oil Contaminants in the Environment  

Science.gov (United States)

This instructional material was created at the 2011 ATEEC Fellows Institute, with the theme of bioremediation of contaminants in the environment. The material provides three learning activities for use in the classroom/laboratory. The activities will provide practice in the use of the scientific method, development of laboratory techniques, experimental design, the interpretation of experimental results, and the ability to understand the role of science within our larger society. Activity three can also be used to introduce students to careers in the oil spill response and regulatory fields as well as to help them understand the stakeholders involved when oil spills occur. This resource is free to download. Users must first create a login with ATEEC's website to access the file.

Everhart, Roger; Newmeister, Jeff; Winterbottom, Wesley L.

2013-06-26

357

Numerical and experimental investigation of the 3D free surface flow in a model Pelton turbine  

International Nuclear Information System (INIS)

This investigation focuses on the numerical and experimental analysis of the 3D free surface flow in a Pelton turbine. In particular, two typical flow conditions occurring in a full scale Pelton turbine - a configuration with a straight inlet as well as a configuration with a 90 degree elbow upstream of the nozzle - are considered. Thereby, the effect of secondary flow due to the 90 degree bending of the upstream pipe on the characteristics of the jet is explored. The hybrid flow field consists of pure liquid flow within the conduit and free surface two component flow of the liquid jet emerging out of the nozzle into air. The numerical results are validated against experimental investigations performed in the laboratory of the Institute of Fluid Mechanics (FLM). For the numerical simulation of the flow the in-house unstructured fully parallelized finite volume solver solver3D is utilized. An advanced interface capturing model based on the classic Volume of Fluid method is applied. In order to ensure sharp interface resolution an additional convection term is added to the transport equation of the volume fraction. A collocated variable arrangement is used and the set of non-linear equations, containing fluid conservation equations and model equations for turbulence and volume fraction, are solved in a segregated manner. For pressure-velocity coupling the SIMPLE and PISO algorithms are implemented. Detailed analysis of the observed flow patterns in the jet and of the jet geometry are presented.

2010-08-01

358

Experimental investigation of electric potentials associated with steady conduction currents in closed superconducting coils  

International Nuclear Information System (INIS)

Granting the success of Maxwell's theory and QED, experimental tests of their limits of accuracy and applicability are important. An area of present interest is possible second-order, velocity-dependent electric fields associated with steady, closed electrical conduction currents in coils at rest in the laboratory. An experimental investigation of the potentials that were associated with currents in type-II superconductors is reported. The resolution of the fundamental questions involved required a detailed study of the source of the potentials. The magnitude variation of the potentials, i.e., the proportionality between the mean and the scatter of the data, was established with greater confidence than previously obtained. Since the potentials from only type-II coils had been studied previously, the basic experiments were repeated also with a type-I superconducting coil made of high-purity Pb. In this case, no potentials that followed current-squared behavior were observed. The upper limit on the null Pb result was 1 part in 190 of what would have been expected on the basis of previous results from type-II coils. Although the cause of the potentials from type II superconducting coils has not been identified, the number of questions and alternatives that need to be pursued in future investigations has been reduced

1978-01-01

359

Experimental investigations on the first Townsend coefficient in pure isobutane  

Energy Technology Data Exchange (ETDEWEB)

In this work we present results of the first Townsend coefficient ({alpha}) in pure isobutane by measuring the current growth as a function of the electric field strength in a pulsed irradiation regime. A Resistive Plate Chamber (RPC)-like configuration was used. To validate this method, as well as to crosscheck the experimental apparatus, measurements of the {alpha} parameter were firstly carried out with pure nitrogen and the results compared to the accurate data available in the literature. The data obtained with isobutane in a field range from 145 Td up to 200 Td were well-matched to those calculated with Magboltz versions 2.7.1 and 2.8.6. The experimental consistency of these results with other published data in the range of 550-1300 Td was very good, as demonstrated by the use of the Korff parameterization.

Lima, I.B. [Instituto de Pesquisas Energeticas e Nucleares, 05508-000 Cidade Universitaria, Sao Paulo (Brazil); Mangiarotti, A. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, Departamento de Fisica da Universidade de Coimbra, 3004-516 Coimbra (Portugal); Departamento de Fisica, Faculdade de Ciencias e Tecnologia, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Vivaldini, T.C. [Instituto de Pesquisas Energeticas e Nucleares, 05508-000 Cidade Universitaria, Sao Paulo (Brazil); Goncalves, J.A.C. [Instituto de Pesquisas Energeticas e Nucleares, 05508-000 Cidade Universitaria, Sao Paulo (Brazil); Departamento de Fisica, Pontificia Universidade Catolica de Sao Paulo, 01303-050 Sao Paulo (Brazil); Botelho, S. [Departamento de Fisica, Pontificia Universidade Catolica de Sao Paulo, 01303-050 Sao Paulo (Brazil); and others

2012-04-01

360

Experimental investigations on the first Townsend coefficient in pure isobutane  

International Nuclear Information System (INIS)

In this work we present results of the first Townsend coefficient (?) in pure isobutane by measuring the current growth as a function of the electric field strength in a pulsed irradiation regime. A Resistive Plate Chamber (RPC)-like configuration was used. To validate this method, as well as to crosscheck the experimental apparatus, measurements of the ? parameter were firstly carried out with pure nitrogen and the results compared to the accurate data available in the literature. The data obtained with isobutane in a field range from 145 Td up to 200 Td were well-matched to those calculated with Magboltz versions 2.7.1 and 2.8.6. The experimental consistency of these results with other published data in the range of 550–1300 Td was very good, as demonstrated by the use of the Korff parameterization.

2012-04-01

 
 
 
 
361

Experimental investigation of defect states in amorphous chalcogenide glasses  

International Nuclear Information System (INIS)

We shall describe an experimental characterization of the important defect states in the model binary chalcogenide semiconductor (As2Se3) which has been systematically doped (to levels of 1017-1020 cm-3) with a variety of predominantly metallic impurities (Mn, Fe, Ni, Cu, Zn, Ga, In, Tl, Li, Na, K, I). Several complementary experimental techniques have been employed including transient hole transport, dc conductivity, electron spin resonance and photoluminescence (PL) measurements. Dramatic changes of the hole drift mobility are observed with the addition of low concentrations of most metallic impurities, but the PL and photo-induced ESR results are generally much less sensitive to these dopants. These findings will be discussed in the context of current models of defects which associate transport traps, paramagnetic and recombination centers with bonding anomalies on the major constituent (As or Se) atoms. (orig.)

1980-01-01

362

Experimental investigations of melt spreading and scaling analysis  

International Nuclear Information System (INIS)

This paper presents results of experimental studies conducted at the Royal Institute of Technology, Division of Nuclear Power Safety (RIT/NPS) on melt spreading. A series of low and intermediate temperature experiments were performed, using different pairs of simulant fluids for melt and coolant. Significant results were obtained from three high-temperature experiments conducted with the corium melt simulant, CaO-B2O3, in a 3.5 meter long by 0.2 meter wide channel. The basemat upon which the melt spread was in one case concrete and in the other two cases a 10mm thick steel plate. Roughly 12 liters of the binary oxide melt at ?1200degC was employed. A scaling relationship between dimensionless spread depth and characteristic spreading time was derived. Experimental measurements from simulant material experiments are presented along with comparisons to the scaling analysis. (author)

1998-05-01

363

A numerical and experimental investigation of electrothermal aircraft deicing  

Science.gov (United States)

Experimental data were obtained for the deicing characteristics of a stationary UH-1H helicopter blade which had been fitted with an electrothermal deicer assembly. The tests were run in the NASA Lewis Icing Research Tunnel, and yielded transient temperature responses for the substrate, heater and abrasion shield at selected positions around the blade. The data at the abrasion shield-ice interface clearly documented when melting, shedding or refreezing occurred. Comparisons were made between the experimental data and a one-dimensional numerical model. The agreement was generally very good, with the simulations being shown to be capable of predicting the transient temperature responses along with phase change and ice shedding. At many blade positions, the model was capable of accurately simulating the thermal response of the electrothermal deicer assembly.

Leffel, K.; Masiulaniec, K. C.; Dewitt, K. J.; Keith, T. G., Jr.

1986-01-01

364

Experimental and numerical investigation of an axisymmetric supersonic jet  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A comprehensive study of a steady axisymmetric supersonic jet of CO2, including experiment, theory, and numerical calculation, is presented. The experimental part, based on high-sensitivity Raman spectroscopy mapping, provides absolute density and rotational temperature maps covering the significant regions of the jet: the zone of silence, barrel shock, Mach disk, and subsonic region beyond the Mach disk. The interpretation is based on the quasi-gasdynamic (QGD) system of equations, and its g...

Mate?, Bele?n; Graur, Irina A.; Elizarova, Tatiana G.; Chirocov, I.; Tejeda, Guzma?n; Ferna?ndez Sa?nchez, Jose? Mari?a; Montero, Salvador

2001-01-01

365

Final Report: Experimental Investigation of Nonlinear Plasma Wake-Fields  

International Nuclear Information System (INIS)

We discuss the exploration of the newly proposed blowout regime of the plasma wakefield accelerator and advanced photoinjector technology for linear collider applications. The plasma wakefield experiment at ANL produced several ground-breaking results in the physics of the blowout regime. The photoinjector R and D effort produced breakthroughs in theoretical, computational, and experimental methods in high brightness beam physics. Results have been published

1997-01-01

366

Numerical and experimental investigation of thermal louvers for space applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermal louvers, using movable or rotating shutters over a radiating surface, have gained a wide acceptance as highly efficient devices for controlling the temperature of a spacecraft. This paper presents a detailed analysis of the performance of a rectangular thermal louver with movable blades. The radiative capacity of the louver, determined by its effective emittance, is calculated for different values of the blades opening angle. Experimental results obtained with a prototype of a spacecr...

Issamu Muraoka; Fabiano Luis de Sousa; Fernando Manuel Ramos; Wilson Roberto Parisotto

2001-01-01

367

Small-scale heterogeneity in sediments : experimental and modelling investigations.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis consists of several studies relating to small-scale heterogeneity in sediments. The principal aim was to further our understanding of processes occurring at microniches. The individual studies consist of: 1) a critical review of previous studies of microniches that used probes with high spatial resolution and modelling approaches; 2) an experimental study of analysis of oxyanions in sediment at high resolution that applied a newly developed preparation method for a combined AgI/Fe...

2008-01-01

368

Experimental investigation of the acoustic properties of liquids foams  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Liquid foams are mixtures of gas and liquid, with a liquid volume fraction $ \\phi _{l} {\\leq}0.3 $, stabilized with surfactants. Because of their composition and structure, liquid foams are very complex and unstable media with particular acoustical properties. Experimental studies are not very numerous; they have shown a strong dependence of the velocity and attenuation of sound on parameters such as $ \\phi _{l}$ and the average bubble size [1]. The existent theories explain a part of the aco...

Pierre, Juliette; Elias, Florence; Gay, Cyprien; Derec, Caroline; Leroy, Valentin

2012-01-01

369

Theoretical and experimental investigations on incompressible flow through labyrinths  

Energy Technology Data Exchange (ETDEWEB)

A low, well defined and cavitation free flow has to be achieved for the leakage of coolant sodium in the annular space between the grid plate sleeve and foot of the core subassembly in the Prototype Fast Breeder Reactor (PFBR). The leakage flow is accompanied by a corresponding pressure drop which is a function of several parameters including turbulence quantities. Theoretical pressure drops for simple annular seals which offer the least flow resistance are found to be low and incapable of fully serving the intended purpose of reducing the sodium pressure profoundly. On the contrary, labyrinth seals provide intricate passages, offer higher resistance to flow and hence can lead to enhanced pressure drops. This paper formulates a theoretical model for estimating the pressure drop taking place in a labyrinth seal by considering the Darcy losses and the vortex losses occurring inside the cavity of the labyrinth. The latter is indeterminable since the angular velocity of the vortex is not amenable for analytical estimation. Hence a square grooved labyrinth was fabricated and tested at different simulated flow rates of water. From the experimental results, the values of a parameter named vortex coefficient are evaluated to complete the theoretical model. The experimental pressure drops are compared with the values calculated by other theoretical models. Using the insight gained, a novel profile of labyrinth is designed. The vortex coefficients for this profile were expectedly and experimentally proved to be higher resulting in its appreciably better performance than the square labyrinth profile.

Asok, S. P.; Arulmurugan, S. [MSEC, Madurai (India); Rajesh, K.; Padmakumar, G.; Govindarajan, S. [IGCAR, Kalpakkam, (India); Sundararajan, T. [Indian Istitute of Tech., Chennai (India); Sankaranarayanasamy, K.; Prabhakar, R.; Vaidyanathan, G. [Regional Engineering College, Trichy (India)

2003-07-01

370

Experimental and computational investigation of percolation in complex polymer nanocomposites  

Science.gov (United States)

The continuing development of polymer nanocomposites has led to increasingly complex morphology, such as the mats of composite nanofibers formed from electrospinning. The formation of particle networks within the composite volume that leads to enhanced properties, such as electrical conductivity, may be influenced by this complex sample geometry. In this work, experimental and computational efforts are utilized to understand and predict the percolation threshold (critical volume fraction) for two cases: single ultra-high aspect ratio fibers (where fiber diameter can be similar to the particle dimensions) and these same fibers arranged in a random mat with up to 80% porosity. 2D and 3D Monte Carlo simulations, modeled on the actual parameters of our experimental system [1], are utilized and the results are compared with our experimental findings. In particular, confinement to fibers increases the percolation threshold; however the multi-fiber pathways available in mats partially reduce this constraint [2]. [1] S.S. Ojha, D.R. Stevens, K. Stano, T. Hoffman, L.I. Clarke, R.E. Gorga, Macromolecules 41, 2509 (2008). [2] D.R. Stevens, L.N. Downen, L.I. Clarke, Phys. Rev. B in press (2008).

Stevens, Derrick; Downen, Lori; Gorga, Russell; Clarke, Laura

2009-03-01

371

A Laboratory Course for Teaching Laboratory Techniques, Experimental Design, Statistical Analysis, and Peer Review Process to Undergraduate Science Students  

Science.gov (United States)

This article describes a 13-week laboratory course called Human Toxicology taught at the University of Otago, New Zealand. This course used a guided inquiry based laboratory coupled with formative assessment and collaborative learning to develop in undergraduate students the skills of problem solving/critical thinking, data interpretation and…

Gliddon, C. M.; Rosengren, R. J.

2012-01-01

372

Experimental and climical investigations of a TSH radioimmunoassay  

International Nuclear Information System (INIS)

The system hypothalamus-pitnitary-thyroid was studied in 427 patients by radioimmunological TSH determination prior to i.v. injection of 600 ?g of synthetic TSH and 30 min p.i. Different commercial TSH test kits were used. The RIA was found to be a sensitive indicator of the functional state of the system. Higher accuracy can be achieved by observing certain criteria. The TSH-RIA is a valuable tool for diagnosis and therapy control of thyroid diseases. With some slight methodological modifications, it has become part of the routine programme of the Giessen thyroid laboratory. The RIA is best suited for early detection of disturbances in the pitnitary-thyroid system; it is less efficient in course control of thyroid diseases. It can be carried out within 30 minutes and, except for two withdrawals of blood, imposes no strain on the patient. (orig./MG)

1979-01-01

373

Investigation of a Chaotic Double Pendulum in the Basic Level Physics Teaching Laboratory  

Science.gov (United States)

First-year physics students at the Technical University of Budapest carry out a wide range of measurements in the Basic Level Physics Teaching Laboratory. One of the most exciting experiments is the investigation of a chaotic double pendulum by a V-scope, a powerful three-dimensional motion tracking system. After a brief introduction to the…

Vanko, Peter

2007-01-01

374

Laboratory Investigation of Free and Driven Oscillations Using a RLC Circuit  

Science.gov (United States)

Describes an experiment for the undergraduate electricity and magnetism or mechanics laboratory to investigate free and driven oscillations. The RLC circuit is pulsed with a pulse generator when free oscillation is being studied and is driven with a low-impedance sinusoidal generator when driven oscillation is being studied. (Author/MLH)

Luke, Keung L.

1975-01-01

375

Fish on Prozac: a simple, noninvasive physiology laboratory investigating the mechanisms of aggressive behavior in Betta splendens  

Science.gov (United States)

The neuromodulator serotonin is an important regulator of aggressive behavior in vertebrates. Experimentally increasing synaptic levels of serotonin with fluoxetine, a selective serotonin reuptake inhibitor, has been shown to reliably decrease the expression of aggressive behavior. Here, we describe a method by which fluoxetine can be noninvasively administered to male Betta splendens (an attractive model for the study of aggressive behavior) and describe a simple laboratory exercise that allows students to experimentally investigate the physiological mechanisms of aggressive behavior. We demonstrate that relatively short-term exposure (3 h) of male bettas to as little as 3 õg/ml of fluoxetine-treated aquarium water is sufficient to reduce the expression of specific aggressive behaviors. We emphasize the physiological concepts that can be addressed with this exercise, including the role of the serotonergic system in regulating aggression, and the interplay of environmental contaminants and physiology in regulating the expression of behavior. We also highlight important aspects of experimental design. This exercise can be flexibly altered to accommodate one or several laboratory periods. It is also low cost, is low impact to the animals, and requires minimal preparation time for instructors.

Sharon E Lynn (The College of Wooster Biology); Joseph M Egar (The College of Wooster Biology); Brian G Walker (Fairfield University Biology); Todd S Sperry (University of Washington Biology); Marilyn Ramenofsky (University of Washington Biology)

2007-12-01

376

Laboratory open-quotes proof of principleclose quotes investigation for the acoustically enhanced remediation technology  

International Nuclear Information System (INIS)

This document describes a three phase program of Weiss Associates which investigates the systematics of using acoustic excitation fields (AEFs) to enhance the in-situ remediation of contaminated soil and ground water under both saturated and unsaturated conditions. The focus in this particular paper is a laboratory proof of principle investigation. The field deployment and engineering viability of acoustically enhanced remediation technology is also examined

1995-10-03

377

ACP Broadsheet No 141: September 1993. Role of endocrine biochemistry laboratories in the investigation of infertility.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The staff and services of the endocrine biochemistry laboratory are essential to the efficient investigation of infertility. Each centre should adopt a detailed strategy for the investigation of the infertile couple which specifies the hormone analyses required at each stage. Appropriate first-line hormone tests should be selected after a thorough clinical history and physical examination of both partners. Second-line hormone testing should be determined from the results of the initial invest...

Beastall, G. H.

1993-01-01

378

Experimental investigation on self-leveling behavior in debris beds  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: The first application of the depressurization method on self-leveling study. Introduce the equivalent power density to evaluate the driving effect. The experimental data presented cover a large parameter range. Discuss the dependency of self-leveling on various parameters. - Abstract: During a hypothetical core-disruptive accident in a sodium-cooled fast breeder reactor, degraded core materials can form debris beds on the core-support structure and/or in the lower inlet plenum of the reactor vessel from rapid quenching and fragmentation of core material pool. Coolant boiling may lead ultimately to leveling of the debris bed that is crucial to the relocation of molten core and heat-removal capability of the debris bed. In the present study, we elected to use depressurization boiling to simulate an axially increasing void distribution in the debris bed. Bottom-heating boiling was also chosen to confirm that characteristics of the self-leveling process do not depend on the boiling mode. Particle size (between 0.5 and 6 mm), shape (spherical and non-spherical), bed volume (between 5 and 8 l) and density (namely of alumina, zirconia, lead and stainless steel) along with boiling intensity and total volume were taken as experimental parameters to obtain the general characteristics of the self-leveling process. A series of experiments with simulant materials were conducted and analyzed in detail. The good concordance of the transient processes obtained from the different boiling methods sufficiently demonstrates that the present results obtained using the depressurization boiling method exhibit these general self-leveling characteristics. Detailed comparisons of deduced time variations of the inclination angle provides qualitative tendencies based on the experimental parameters considered influential to self-leveling behavior. The rationale behind the definition introduced for equivalent power density is also presented.

Zhang Bin, E-mail: b_zhang@nucl.kyushu-u.ac.j [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan); Harada, Tetsushi; Hirahara, Daisuke; Matsumoto, Tatsuya; Morita, Koji; Fukuda, Kenji [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan); Yamano, Hidemasa; Suzuki, Tohru; Tobita, Yoshiharu [Advanced Nuclear System R and D Directorate, Japan Atomic Energy Agency, 4002 Narita, O-arai, Ibaraki 311-1393 (Japan)

2011-01-15

379

Experimental investigations of the electron cloud key parameters  

International Nuclear Information System (INIS)

Motivated by a potential electron cloud instability and the possible existence of electron multipacting in the LHC vacuum system, that may result in additional gas desorption and unmanageable heat loads on the cryogenic system, and extensive experimental research program is underway at CERN to quantify the key parameters driving these phenomena. Parameters, such as: photoelectron yield, photon reflectivity, secondary electron yield etc from industrially prepared surfaces have been quantified. In addition to their dependence on photon dose the effect of temperature and presence of external fields has also been studied. (author)

2000-02-01

380

Experimental Investigations of the Electron Cloud Key Parameters  

CERN Document Server

Motivated by a potential electron cloud instability and the possible existence of electron mulitpacting in the LHC vacuum system, that may result in additional gas desorption and unmanageable heat loads on the cryogenic system, an extensive experimental research program is underway at CERN to quantify the key parameters driving these phenomena. Parameters, such as: photoelectron yield, photon reflectivity, secondary electron yield etc. from industrially prepared surfaces have been quantified. In addition to their dependence on photon dose the effect of temperature and presence of external fields has also been studied.

Anashin, V V; Cimino, R; Collins, I R; Dostovalov, R V; Fedorov, N V; Gómez-Goñi, J; Gröbner, Oswald; Henrist, Bernard; Hilleret, Noël; Krasnov, A A; Laurent, Jean Michel; Malyshev, O B; Pyata, E E; Pivi, M

1999-01-01

 
 
 
 
381

An experimental investigation of pulse tube refrigeration heat transfer rates  

International Nuclear Information System (INIS)

Experiments have been performed to show that the heat exchanges between the gas and the walls are more important in the basic pulse tube than in the orifice pulse tube. It is shown that the R/delta ratio well characterizes these heat exchanges. A new concept for describing pulse tube operation is introduced which involves gas-gas heat exchanges. It is shown qualitatively that there must exist heat exchanges elsewhere than in the heat exchangers. An experimental apparatus is described which makes it possible to study these parameters and to obtain good performance. An 85-K temperature limit and a 4-W cold power at 100 K were achieved. 10 refs

1989-07-24

382

Methodic aspects of experimental investigation of optimality of heterogeneous shields  

International Nuclear Information System (INIS)

On the basis of the effective neutron and gamma radiation attenuation constants and the concept of efficiency function the possibility to apply the experimental variational method for optimization of multy-layered biological shields is proved. The dependence of the flux functional and the efficiency function on the interface coordinates is derived. The practical application of the method for analyzing both two- and multy-layered specific shields with and without account for the neutron-induced secondary gamma radiation is discussed. It is concluded that the method proposed provides one with a useful fool for transferring the results of simulating experiments on designed physical facilities

1978-01-01

383

Development and experimental investigation of new seals for cryoalternators  

Energy Technology Data Exchange (ETDEWEB)

One of the vital problems in developing high-speed cryogenically cooled electrical machines with a cryostat common to rotor and stator is availability of reliable shaft seals. Depending on the electric machine design, reliable rotary seals are required both for working media sealing and for maintaining vacuum in rotating cryostats. Newly designed rotary seals employ the principles of radial hydrodynamic sealing. Tentative experimental studies proved the advantages of the new design over the traditional radial hydrodynamic seals. Pressure difference withstood by the new seals with no obvious sealed media leaks is about 1.5 times greater than that provided by a conventional seal.

Ganzhinov, I.S.; Sapozhnikov, V.A.; Tutaev, V.A. [VNIIElectromash, St. Petersburg (Russian Federation)

1996-12-31

384

Shock induced response of structural systems analytical and experimental investigations  

International Nuclear Information System (INIS)

This contribution refers to the behaviour of reinforced concrete structures impacted by deformable missiles. The difference with hard missile impact problems, about which generally more knowledge exists, are point out. Structural response effects beyond the immediate contact face vicinity, beyond the local load introduction zone - i.e. effects of punching shear, of bending, of vibration transmission etc. - are emphasized. Two- and three-dimensional analytical approaches verified by experimental evaluations are discussed, and typical phenomena of the behaviour of reinforced concrete structures subjected to impact loads are demonstrated. (Author)

1984-10-03

385

The Endogenous Evolution of Market Institutions: An Experimental Investigation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study an experimental market in which the structure of the information flows is endogenized. When making an offer, traders choose not only the price at which they are prepared to trade, but also the subset of traders they want to inform about the offer. This design allows for two extreme institutions as special cases. If traders always inform every other trader about each offer, the resulting institution is equivalent to a double auction. If, on the other hand, traders always inform only o...

1998-01-01

386

Experimental investigations of interaction of supercritical electron beams with plasma  

International Nuclear Information System (INIS)

The first section of the collective ions acceleration based on simultaneous temporal and spatial modulation of relativistic electron beam (REB) was studied experimentally. The virtual cathode was originated in the electrodynamic structure consisting of two tubes with different diameters (jump of electrodynamics) by REB, produced in magnetically insulated diode. At plasma assistance the low-frequency oscillations of REB current and the low-frequency microwave radiation were obtained due to the virtual cathode periodical relaxation in the processes of charge compensation by ionized residual gas

2002-01-01

387

Experimental investigation of a novel desiccant cooling system  

Energy Technology Data Exchange (ETDEWEB)

Desiccant based air conditioning systems are a suitable way to improve indoor air quality due to its superior humidity control. In this study, a novel desiccant based air conditioning system is designed and tested experimentally to improve the indoor air quality and reduce energy consumption. In the system studied, a heat exchanger, which is not used in this type of systems, for pre-heating the regeneration air with exhaust air is used. This paper reports results of initial operation and operational procedures. The performance of the system and its components is discussed. (author)

Huerdogan, Ertac; Yilmaz, Tuncay [Department of Mechanical Engineering, Faculty of Engineering and Architecture, Cukurova University, 01330 Balcali, Adana (Turkey); Bueyuekalaca, Orhan [Department of Energy Systems Engineering, Faculty of Engineering, Osmaniye Korkut Ata University, 80000 Osmaniye (Turkey); Hepbasli, Arif [Department of Mechanical Engineering, Faculty of Engineering, Ege University, 35100 Bornova, izmir (Turkey)

2010-11-15

388

Power characteristics in GMAW: Experimental and numerical investigation  

Energy Technology Data Exchange (ETDEWEB)

The voltage and power distributions in gas metal arc welding (GMAW) were studied both experimentally and numerically. The principal voltage drop takes place in the arc, which also constitutes the dominant power contribution. Within the arc, the dominating voltage contributions are from the arc column and the cathode fall, while the anode fall and the electrode regions are less significant. The power input to the arc column increases with both increasing current and increasing arc length. These results indicate that it is critical to control the arc length in order to control the power input to the system.

Joensson, P.G. [MEFOS, Luleaa (Sweden); Szekely, J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering; Madigan, R.B.; Quinn, T.P. [NIST, Boulder, CO (United States). Materials Reliability Div.

1995-03-01

389

Experimental investigation of heat losses at the PACTEL facility  

International Nuclear Information System (INIS)

Some methods are described in the present study for determining heat losses of experimental test facilities. Two different methods were chosen to be applied for the PACTEL. The experiment based on the transient method was performed in June, 1990, while results of earlier natural circulation tests could serve as a comparison between two procedures. Calculated results and plots show that the formation and values of heat losses have come up to the expectations however additional experiment is needed to obtain information about the distribution of heat losses throughout the facility. (orig.). (4 refs., 17 figs., 1 tab.)

1990-01-01

390

Experimental investigation of a filter with natural sorbent charge for runoff cleaning from heavy metals and petroleum products  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An experimental investigation on the removal of heavy metals (HM) and petroleum products (PP) from a solution by natural sorbents zeolite and vermiculite was carried out in a laboratory pilot-scaled test bench. For this purpose a model of a runoff filter which was invented by the authors was used. 25 kg of natural zeolite and 2 kg of vermiculite were used for the filter charge. An experimental solution of 20 l contained 1 g/l of HM Cu, Pb, Zn, Ni and Mn nitrates and 200 ml of PP gasoline and ...

Baltre?nas, Pranas; Brannwall, Evelina

2006-01-01

391

Numerical and experimental investigation of direct injection fuel spray characteristics  

Energy Technology Data Exchange (ETDEWEB)

A liquid sheet model for the prediction of the development of a hollow-cone spray emerging from a pressure-swirl atomiser into quiescent air is examined in the present paper. The model consists of a sheet atomisation model and a model for the subsequent spray development. The sheet atomisation process is modelled by introducing fuel ''blobs'' of size equal to the sheet thickness at a distance equal to the breakup length of the liquid sheet away from the injector, while the subsequent breakup of the blobs is modelled using the Reitz-Diwakar model. The model is implemented within the STAR-CD code. In addition, experimental results were obtained using laser-diffraction and phase-Doppler particle analysis for droplet size measurements, while for the determination of macroscopic spray structure a high-speed rotating drum camera and an Oxford Lasers copper-vapour laser were utilised. The numerical results are compared against experimental data in the form of spray tip penetration and temporal development of arithmetic mean droplet diameter, as well as radial distribution of Sauter mean diameter. The numerical model predicts the early spray tip velocity accurately and the droplet sizes with acceptable deviation. (author)

Stavropoulos, M.; Papadakis, G.; Yianneskis, M. [King' s College, London (United Kingdom). Dept. of Mechanical Engineering; Williams, P.A.; O' Donoghue, S. [University College, London (United Kingdom). Dept. of Mechanical Engineering

2000-07-01

392

Reduction of friction in fluid transport: experimental investigation  

Directory of Open Access Journals (Sweden)

Full Text Available La reducción de fricción o de arrastre (DR mediante el uso de soluciones poliméricas o surfactantes es sin duda alguna la técnica de reducción de fricción para flujos turbulentos en tuberías más efectiva (es posible obtener reducciones de hasta un factor de 8 en los coeficientes de fricción en segmentos de tuberías rectas. Desde el punto de vista fundamental, el estudio del fenómeno de DR ofrece la oportunidad de comprender mejor flujos turbulentos; desde el punto de vista práctico, la DR puede ser usada con propósitos de ahorro en potencia de bombeo. La implementación comercial de estos aditivos se ha llevado a cabo con éxito en el transporte de petróleo, y la investigación necesaria para la implementación de estas soluciones en muchas otras aplicaciones sigue en proceso, p.ej., en sistemas centrales de calefacción y aire acondicionado, sistemas hidrónicos en edificios, desagües, irrigación, procesos industriales, etc. Nuestros esfuerzos se han enfocado en dos áreas principales: (A investigación experimental sobre la transferencia de momentum y calor para soluciones reductoras de fricción, y (B la implementación de estas soluciones en sistemas hidrónicos de enfriamiento en edificios con el propósito de ahorrar energía. Este documento pretende dar una noción general de la investigación experimental que llevamos a cabo en nuestro laboratorio de dinámica de fluídos no-Newtonianos, reología, y transferencia de calor en la UCSB

G. Aguilar

2006-01-01

393

Experimental stand for investigation of electron channeling into crystals  

International Nuclear Information System (INIS)

In the Lab. for Experimental Physics of Almaty State Univ. the works are carrying out for creation of the automated complex (stand) for study electron channeling phenomenon and properties of Kumakhov gamma-radiation. The complex one can be divide on 5 subsystems: 1) electron source on the base of Ehlektronika-type linear accelerator; 2) subsystem for forming and transporting of electron beams up to crystal; 3) goniometer subsystem on the ground of goniometer of high precision with five degrees of freedom; 4) registration beta- and gamma- detectors; 5) control and measuring subsystem. Impulse accelerator EhLU-6 type is the electron source, the energy of electrons is from 4 up to 7 MeV, mean current is equal to 600 ?A, impulse duration is equal to 4 ?s, frequency of following is equal to 200 Hz. Number of unique devices has been created during the design and realization of different units and subsystems of the experimental stand. Its are distributing chamber from monolithic titanium block, collimator of particles with very low angular divergence, precision goniometer of high accuracy with five degrees of freedom, registration system for soft gamma radiation which can be used in different fields of science and engineering

1995-01-01

394

Investigating Climate Change and Reproduction: Experimental Tools from Evolutionary Biology  

Directory of Open Access Journals (Sweden)

Full Text Available It is now generally acknowledged that climate change has wide-ranging biological consequences, potentially leading to impacts on biodiversity. Environmental factors can have diverse and often strong effects on reproduction, with obvious ramifications for population fitness. Nevertheless, reproductive traits are often neglected in conservation considerations. Focusing on animals, recent progress in sexual selection and sexual conflict research suggests that reproductive costs may pose an underestimated hurdle during rapid climate change, potentially lowering adaptive potential and increasing extinction risk of certain populations. Nevertheless, regime shifts may have both negative and positive effects on reproduction, so it is important to acquire detailed experimental data. We hence present an overview of the literature reporting short-term reproductive consequences of exposure to different environmental factors. From the enormous diversity of findings, we conclude that climate change research could benefit greatly from more coordinated efforts incorporating evolutionary approaches in order to obtain cross-comparable data on how individual and population reproductive fitness respond in the long term. Therefore, we propose ideas and methods concerning future efforts dealing with reproductive consequences of climate change, in particular by highlighting the advantages of multi-generational experimental evolution experiments.

Oliver Y. Martin

2012-09-01

395

[Experimental investigation of intergenerational interaction and older adults' generativity].  

Science.gov (United States)

This study examined the effects of the reactions of younger adukts toward older adults on the psychological attributese and behavior of elderly. Participants were 34 older male adults aged 60-82 years. They completed a questionnaire on generativity before and after the experimental condition, and were also observed taking flyers on different topics after the experiment. They were assigned to the younger condition or the same generation condition. In both conditions, the participants were asked to talk to recipients about experiences from their youth and the wisdom they have gained. The recipients responded to the participants in either a positive or a neutral way. The results showed that generativity was promoted most when the younger recipients responded in a positive manner, whereas the neutral reactions of younger recipients led to the inhibition of generativity. Younger persons' positive reactions promoted the participants' helping behaviors, as indicated by the flyers they took. The present study shows increases in the generativity of the elderly following positive reactions from younger recipients not only on questionnaires but also in an experimental setting. PMID:24669505

Tabuchi, Megumi; Miura, Asako

2014-02-01

396

Water Sloshing in Rectangular Tanks – An Experimental Investigation & Numerical Simulation  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the steps involved in designing a test rig to study water sloshing phenomenon in a 560 x 160 x 185 mm PVC rectangular container subjected to sudden (impulsive impact. The design encompasses the construction of the testing facility and the development of a proper data acquisition system capable of capturing the behavior of pre- and post impact water motion inside the tank. Fluid motion was recorded using a video camera for flow visualization purpose. Two water levels of 50 and 75% full as well as two driving weights of 2.5 and 4.5 kg were used. The experimental study was supplemented by a computational fluid dynamics study to mimic the fluid motion inside the tank. Examination of CFD capability to predict the behavior of the free surface of the fluid during the containe