WorldWideScience
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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

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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

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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

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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

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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

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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.

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Laboratory Investigations on Percussive Drilling  

Science.gov (United States)

The laboratory investigation was carried out on ten rock samples using pneumatic drill with drill bits of different diameters. In general, the process of drilling always produces sound. Sound is generated from the bit-rock interface regardless of the material of the bit used in drilling. The predicted sound level and penetration rate are a product of the drill power and the physical properties of the rocks penetrated. Rock samples were collected from the field and physical properties of the rocks were determined in the laboratory. The sound level and penetration rates were correlated with the rock properties. The compressive strength and abrasivity exhibit strong correlations with the sound level and penetration rate. It was concluded that, among the rock properties included in this study, the compressive strength and abrasivity values are the dominant ones affecting the penetration rate and sound level of percussive drills. Though ten rock samples have been covered in this study, detailed analysis of only one of them is presented.

Kivade, S. B.; Murthy, Ch. S. N.; Vardhan, Harsha

2013-10-01

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Experimental investigations of long-term interactions of molten UO2 with MgO and concrete at Argonne National Laboratory  

International Nuclear Information System (INIS)

Experimental work at Argonne is being performed to investigate the long-term molten-core-debris retention capability of the ex-vessel cavity following a postulated meltdown accident. The eventual objective of the work is to determine if normal structural material (concrete) or a specifically selected sacrificial material (MgO) located in the ex-vessel cavity region can effectively contain molten core debris. The materials under investigation at ANL are various types of concrete (limestone, basalt and magnetite) and commercially-available MgO brick. Results are presented of the status of real material experimental investigation at ANL into (1) molten UO2 pool heat transfer, (2) long-term molten UO2 penetration into concrete and (3) long-term molten UO2 penetration into refractory substrates. The decay heating in the fuel has been simulated by direct electrical heating permitting the study of the long-term interaction

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Experimental investigation of soil filtration using geotextiles  

OpenAIRE

The doctoral research is a study of soil filtration by geotextile fabrics, with the ultimate objective of improving design and long-term performance of underdrain systems in highways.^ The experimental investigation was conducted in the laboratory using the best available techniques, the Flexible Wall Gradient Ratio Test and the Rapid Retention Test, in order to assess soil-filter compatibility and monitor geotextile clogging, for a range of materials and testing conditions. Field informati...

Lee, Sang-ho

2006-01-01

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Laboratory investigation of Acanthamoeba keratitis.  

OpenAIRE

Following the diagnosis of Acanthamoeba keratitis in a contact lens wearer, the antimicrobial susceptibility of the clinical isolate and the environmental source of the infection were investigated. Contrary to previous reports, in vitro antimicrobial testing showed that the infecting strain was inherently resistant to propamidine isethionate. Restriction endonuclease digestion analysis of Acanthamoeba whole-cell DNA of strains isolated from the patient's cornea, contact lens storage container...

Kilvington, S.; Larkin, D. F.; White, D. G.; Beeching, J. R.

1990-01-01

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Experimental investigation of cavity flows  

Energy Technology Data Exchange (ETDEWEB)

This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

Loeland, Tore

1998-12-31

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Evaluating students’ learning from laboratory investigations  

OpenAIRE

The concept of investigation is a central concept in science. Throughout the centuries, both the meaning of the concept and the characteristics of the processes associated with a scientific investigation have been strongly dependent on the dominant views of science. Nowadays, scientific investigation should be conceptualized as a problem-solving activity. Within the context of Science Education, laboratory investigations have had no clear meaning and been often non-differentiated ...

Leite, Laurinda

2005-01-01

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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

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Biomedical investigations on experimental neutron capture therapy with cold neutrons in the laboratory ELLA on the research reactor Dido in Juelich  

International Nuclear Information System (INIS)

Neutron capture therapy (NCT) with thermal neutrons and suitable 10B compounds permits the successful treatment of brain tumours via the reaction 10B(n,?)7Li. In the past the effects of new organic 10B amino acid analogues have been analysed by irradiation of solid tumours (EO 771) transplanted on the hind legs of mice (C57 B1/6j) at the reactor Merlin in Juelich. Recently the new external neutron laboratory ELLA at the reactor Dido, with a cold source and 58Ni coated neutron guide tubes came into operation and a universal irradiation facility (EKN) may also be used for biological and bioanalytical experiments. The measurement of neutron flux density and gamma dosimetry has demonstrated the high quality of this cold neutron beam. This facility was used for the analysis of 10B tumour slices and in blood samples from mice after the injection of 10B Hatanaka SS compound using the solid state detector Kodak-Pathe LR-115. (author)

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Laboratory models for the investigation of lymphangiomatosis.  

Science.gov (United States)

Lymphangiomatosis is an uncommon proliferative disorder of the lymphatic vasculature whose etiology remains poorly understood. The lymphangiomatosis spectrum encompasses a remarkable heterogeneity in its potential presentation, including micro- and macrocystic isolated lymphatic malformations, thoracic and intraabdominal diffuse lymphangiomatosis, and osseous and soft-tissue presentations known as Gorham-Stout disease. Recent therapeutic advances are empirical in nature or, at best, inferential, reflecting the scanty availability of laboratory-based model systems for the mechanistic study of this disease. Several promising model systems are reviewed here. The laboratory investigation of lymphangiomatosis will likely continue to benefit from the remarkable growth of insights into the mechanisms of lymphangiogenesis and vascular development. PMID:25173588

Rockson, Stanley G

2014-11-01

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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

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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

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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.

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Laboratory Investigations of Stratospheric Halogen Chemistry  

Science.gov (United States)

A final report for the NASA-supported project on laboratory investigations of stratospheric halogen chemistry is presented. In recent years, this project has focused on three areas of research: (1) kinetic, mechanistic, and thermochemical studies of reactions which produce weakly bound chemical species of atmospheric interest; (2) development of flash photolysis schemes for studying radical-radical reactions of stratospheric interest; and (3) photochemistry studies of interest for understanding stratospheric chemistry. The first section of this paper contains a discussion of work which has not yet been published. All subsequent chapters contain reprints of published papers that acknowledge support from this grant.

Wine, Paul H.; Nicovich, J. Michael; Stickel, Robert E.; Hynes, Anthony J.

1997-01-01

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Experimental investigation of new neutron moderator materials  

Energy Technology Data Exchange (ETDEWEB)

In this study we present experimental investigation of thermal neutron energy spectra produced by lead and bismuth hydroxides (Pb(OH){sub 2}, and Bi(OH){sub 3}). The experimental energy spectra are compared with a thermal neutron energy spectrum of water measured in the same geometry. We present an MCNPX geometry model used to help with the experimental data interpretation. We demonstrate a very good reproduction of the experimental thermal neutron energy spectrum produced by the water moderator. We show a sensitivity study with the Pb(OH){sub 2}, and Bi(OH){sub 3} materials on different combinations of thermal neutron scattering kernels.

Mocko, Michal [Los Alamos National Laboratory; Daemen, Luke L [Los Alamos National Laboratory; Hartl, Monika [Los Alamos National Laboratory; Huegle, Thomas [Los Alamos National Laboratory; Muhrer, Guenter [Los Alamos National Laboratory

2010-01-01

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Experimental investigation of new neutron moderator materials  

International Nuclear Information System (INIS)

In this study we present experimental investigation of thermal neutron energy spectra produced by lead and bismuth hydroxides (Pb(OH)2, and Bi(OH)3). The experimental energy spectra are compared with a thermal neutron energy spectrum of water measured in the same geometry. We present an MCNPX geometry model used to help with the experimental data interpretation. We demonstrate a very good reproduction of the experimental thermal neutron energy spectrum produced by the water moderator. We show a sensitivity study with the Pb(OH)2, and Bi(OH)3 materials on different combinations of thermal neutron scattering kernels.

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EXPERIMENTAL INVESTIGATIONS OF COARSE AGGREGATE RECYCLED CONCRETE  

Directory of Open Access Journals (Sweden)

Full Text Available In India, a huge quantity of construction and demolition wastes is produced every year. These waste materials need a large place to dump and hence the disposal of wastes has become a problem. And the continuous use of natural resources for making conventional concrete leads to the reduction in their availability and results in the increase of the cost of the coarse aggregate and fine aggregate. The possible use of recycling demolition waste as coarse aggregate in the construction industry is thus increasing importance. In addition to the environmental benefits in reducing the demand of land for disposing the waste, the recycling of demolition wastes can also help to conserve the natural resources. When recycled coarse aggregate is used in structural concrete, the assessment of physical, mechanical and durable characteristics of recycled coarse aggregate is very important. The physical and mechanical properties of concrete with the recycled coarse aggregate (RCA are to be evaluated to assess its application as structural concrete. The present work is directed towards the evaluation of concrete using full replacement of natural coarse aggregate (NCA with RCA. The experimental results of mechanical and durability properties are also evaluated and compared with NCA concrete. Recycled coarse aggregate used in the concrete preparation was obtained from the tested laboratory concrete specimens. Tests were carried out to obtain the mechanical properties of RCA such as compressive strength and durability of concrete using rapid chloride permeability test (RCPT. The main problem with RCA concrete is high percentage of water absorption. RCA has high compressive strength comparable to the natural coarse aggregate concrete. This is mainly due to high amount of attached mortar on the surface of the recycled coarse aggregate and highly angular nature of RCA leads to poor quality of coarse aggregate. In RCPT, the chloride penetrating rate is “Moderate” for all grades of concrete with NCA and “High” for all grades of concrete using RCA. Based on the results of the experimental investigation, the RCA can be recommended as structural concrete in limited applications due to its high percentage of water absorption property of RCA.

D.V. Prasada Rao

2014-11-01

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Laboratory Investigation of Lower Hybrid and Whistler Wave Characteristics*  

Science.gov (United States)

Many interesting in situ and laboratory observations of whistler and lower hybrid waves have been made over the past few decades. Observations such as these have prompted NRL Space Physics Simulation Chamber investigations of nonlinear whistler wave dynamics and lower hybrid solitary structures. For the initial experiments, we have fabricated and tested transmitting and receiving magnetic loop antennas and crossed electric field dipole receiving antennas. Electromagnetic modes launched in the Space Chamber plasma have been identified as whistler waves. Propagation characteristics of both whistler and lower hybrid waves have been investigated in homogeneous plasma conditions. Experiments into the interaction of whistler/lower hybrid waves with pre-existing plasma density structures have begun. In addition, preliminary investigations into the nonlinear properties of whistlers have provided indication of whistler wave ducting. Experimental results related to the propagation characteristics of whistler/lower hybrid waves under these conditions will be presented. *Work supported by the Office of Naval Research and NASA.

Amatucci, W. E.; Blackwell, D.; Walker, D. N.; Ganguli, G. I.; Gatling, G.; Schuck, P. W.; Compton, C.

2006-12-01

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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

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Laboratory investigation of deaths due to anaphylaxis.  

Science.gov (United States)

To establish a useful laboratory protocol to investigate possible cases of fatal anaphylaxis, we measured mast-cell-derived tryptase levels and allergen-specific immunoglobulin E (IgE) antibody levels in sera obtained prior to or within 24 h after death from 19 anaphylaxis victims. Elevated serum tryptase levels (range = 12 ng/mL to 150 micrograms/mL) were found in nine of nine Hymenoptera sting fatalities, six of eight food-induced fatalities, and two of two reactions to diagnostic therapeutic agents. Tryptase levels were normal (less than 10 ng/mL) in 57 sequential sera obtained postmortem from six control patients. Tryptase could not be measured in pleural or pericardial fluids for technical reasons. Serum IgE antibodies were elevated in five of the nine Hymenoptera sting fatalities and in eight of the eight fatal food reactions; assays were unavailable for the two diagnostic/therapeutic agents. If elevated, the victim's serum IgE antibodies to food could be used to identify allergens in uneaten portions of foods consumed shortly before the anaphylactic event. IgE antibodies were moderately stable during storage in a variety of anticoagulants at room temperature for up to 11 weeks. Elevated mast-cell-derived tryptase levels in postmortem sera reflect antemortem mast cell activation and may be used as a marker for fatal anaphylaxis. If assays are available for IgE antibodies to relevant allergens, such assays provide evidence for antemortem sensitization; these assays may be modified to identify allergens in foods consumed by victims of food-induced anaphylaxis. PMID:1856650

Yunginger, J W; Nelson, D R; Squillace, D L; Jones, R T; Holley, K E; Hyma, B A; Biedrzycki, L; Sweeney, K G; Sturner, W Q; Schwartz, L B

1991-05-01

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An Interdisciplinary Laboratory to Teach Experimentation. Final Report.  

Science.gov (United States)

The author views the primary purpose of the modern engineering laboratory as teaching the student how to experiment. An attempt is made to update the engineering laboratory and make it generally meaningful for all students, whether headed for graduate school or an industrial job. The intent is to broaden the experimental picture so that students…

Schenck, Hilbert, Jr.

27

Experimental investigation of quadrupole virtual photon spectrum  

International Nuclear Information System (INIS)

To test experimentally the quadrupole virtual photon spectrum calculation, the (e,?) excitation function of an isolated 2+ level at 20.14 MeV in 24Mg was measured. The most recent calculations in DWBA, including nuclear size effects, are compared to this experimental curve. The differential cross section d2?/d?dE was measured 480, 900, 1320 in the laboratory system, for total electron energies of 20.0, 20.8, 21.5, 24.0, 26.0, 28.0, 30.0, 32.0, 36.0, and 40.0 MeV. The reduced matrix element B(E2) of the 20,14 MeV level is extracted as a secondary product of this work. (author)

28

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

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Experimental investigation of use of horizontal wells in waterflooding  

Energy Technology Data Exchange (ETDEWEB)

The present experimental study is conducted to investigate the effect of horizontal production well in waterflooding when conventional vertical production well stops oil production. Laboratory experiments have been performed on three-dimensional sand pack models. In the waterflooding experiments, the horizontal production well is turned on after the complete extraction of oil from the vertical production well. The experimental results show that horizontal well increases the ultimate recovery by waterflooding significantly when oil production stops from the conventional vertical production well. Moreover, the position of the horizontal well either at top or bottom of the sand pack has negligible effect on ultimate oil recovery for the sand packs used. (author)

Hadia, N.; Chaudhari, L.; Mitra, Sushanta K. [Department of Mechanical Engineering, IITB-ONGC Joint Research Centre, Indian Institute of Technology Bombay, Mumbai, 400 076 (India); Vinjamur, M. [Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, 400 076 (India); Singh, R. [Institute of Reservoir Studies, ONGC, Ahmedabad (India)

2007-04-15

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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

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Experimental investigation of NIRS spatial sensitivity  

OpenAIRE

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

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Experimental Emulsified Diesel and Benzen Investigation  

OpenAIRE

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 torqu...

Suleiman Abu-Ein

2010-01-01

33

Submillimeter Laboratory Investigations: Spectroscopy and Collisions  

Science.gov (United States)

Currently, millimeter-wave and submillimeter-wave spectroscopy is conducted in our laboratory on several different types of spectrometers. Our standard spectrometer utilizes the output of a phase-locked klystron operating in the 40-60 GHz region, which is sent into a crossed-waveguide harmonic generator, or "multiplier". The high frequency millimeter-and submillimeter-wave radiation is transmitted via quasi-optical techniques through an absorption cell and then onto a detector, which is either an InSb hot electron bolometer cooled to 1.4 K or a Si bolometer cooled to 0.3 K. The detector response is sent to a computer for measurement and analysis. The frequency range produced and detected in this manner goes from 80 GHz to upwards of 1 THz. Spectra are normally taken with source modulation, with line frequencies typically measured to an accuracy of 50-100 kHz. Higher accuracy is available when needed. Recently, we developed a new, broad-band spectrometer in our laboratory based on a free-running backward wave oscillator (BWO) of Russian manufacture as the primary source of radiation. The so-called FASSST (fast-scan submillimeter spectroscopic technique) system uses fast-scan and optical calibration methods rather than the traditional locking techniques. The output power from the BWO is split such that 90% goes into the absorption cell while 10% is coupled to a 40-meter Fabry-Perot cavity, which yields fringe? for frequency measurement. Results from this spectrometer on the spectrum of nitric acid (HNO3) show that 100 GHz of spectral data can be obtained in 5 seconds with a measurement accuracy of 50 kHz. Currently, the frequency range of the FASSST system in our laboratory is roughly 100-700 GHz.

Herbst, Eric; DeLucia, Frank C.

2002-01-01

34

Laboratory investigation on super-Earths atmospheres  

Science.gov (United States)

In the framework of Atmosphere in a Test Tube, at the Astronomical Observatory of Padova (INAF) we are going to perform experiments aimed to understand the possible modification of the atmosphere by photosynthetic biota present on the planet surface. This goal can be achieved simulating M star planetary environmental conditions. The bacteria that are being studied are Acaryochloris marina, Chroococcidiopsis spp. and Halomicronema hingdechloris. Tests will be performed with LISA or MINI-LISA ambient simulator in the laboratory of the Padova Astronomic Observatory. In this paper we describe the whole road map to follow in order to perform experiments and to obtain useful data to be compared with the real ones that will be obtained by the future space missions. Starting by a fiducial experiment we will modify either environmental and thermodynamical properties in order to simulate both real irradiation by an M star and gas mixture mimicing super earths atmospheres. These laboratory tests could be used as a guideline in order to understand whether chemical disequilibrium of O2, CO2 and CH4 could be ascribed to biotic life forms.

Erculiani, M. S.; Claudi, R. U.; Lessio, L.; Farisato, G.; Giro, E.; Cocola, L.; Billi, D.; D'alessandro, M.; Pace, E.; Schierano, D.; Benatti, S.; Bonavita, M.; Galletta, G.

2014-04-01

35

Laboratory investigation of visible shuttle glow mechanisms  

Science.gov (United States)

Laboratory experiments designed to uncover mechanistic information about the spectral and spatial characteristics of shuttle glow were conducted. The luminescence was created when a pulse of O atoms traveling at orbital velocities was directed toward NO molecules previously adsorbed to aluminum, nickel, and Z306 Chemglaz (a common baffle black) coated surfaces held at various temperatures. Spectral and spatial measurements were made using a CCD imaging spectrometer. Corroborative spectral information was recorded in separate measurements using a scanning monochromator and gated photomultiplier arrangement. The e-folding distance at several temperatures was calculated from images of the surface glow using the photometrics image processing capability of the imaging spectrometer. The e-folding distance was not altered as a function of incoming O beam velocity. The results are presented and the observations provide direct evidence that the visible shuttle glow results from recombination of oxygen atoms and surface bound NO.

Leone, A.; Swenson, G. R.; Caledonia, G. E.; Holtzclaw, K. W.

1991-01-01

36

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

37

Experimental and numerical investigations of plasma turbulence  

International Nuclear Information System (INIS)

Turbulence in plasmas has been investigated experimentally and numerically. The work described here is divided into four parts: - experiments on edge turbulence in a single-ended Q-machine. Convective cells are investigated in detail together with the anomalous transport caused by them. - Numerical simulation of the edge turbulence in the Q-machine. This simulation uses spectral methods to solve Euler's equation in a cylindrical geometry. - Measurements on wave propagation and the ion beam instability in an unmagnetized plasma with an ion beam with a finite diameter. - Development of software for the automated acquisition of data. This program can control an experiment as well as make measurements. It also include a graphics part. (author) 66 ills., 47 refs

38

Experimental Investigations of Magnetic Phase Transitions  

Science.gov (United States)

Our understanding of magnetic phase transitions has progressed rapidly in recent years, and one material that is currently of theoretical interest is the metamagnet, dysprosium aluminum garnet (DAG). This is a well understood, model system that can be used to test theories of tricritical behavior. However, the experimental investigation of this material requires high resolution measurements and in this thesis several experimental methods were developed for this purpose. Methods of measuring magnetic properties using optical techniques were investigated as they allow small regions of the sample to be measured and thereby reduce the rounding effects produced by nonuniform samples. An apparatus for measuring the Faraday rotation was developed to measure the magnetization of samples in the shape of thin plates and spheres. In addition, a method of measuring the light scattered from domains in spherical samples was developed to locate the first-order phase boundaries. The shape of the sample was important as effects due to inhomogeneous demagnetizing fields were observed for nonellipsoidal samples. A computer model using finite elements investigated this effect and general predictions were made of the size of these effects in materials with different equations of state and sample shapes. This method was also used to investigate the effects of imperfections (pores, surface pits) on magnetic measurements. A method of measurement using mutual inductance coils was constructed to measure the a.c. susceptibility. In addition to measurements of the susceptibility at various frequencies, the out-of-phase component of the susceptibility was found to give a sensitive measurement of the location of the phase transition. The above methods were used to investigate the behavior of DAG near its tricritical point. The general behavior that was measured was consistent with previous investigations. However, close to the tricritical point, previously unreported domain-like states and very long relaxation times (>0.1 seconds) were observed and these precluded simple analysis of the results. Current models of tricritical behavior do not take into account these processes and, therefore, the measurements of this thesis indicate the need for new theoretical developements.

Brug, James Alexander

39

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 + Fe2O3)/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 + Fe2O3, 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)

40

Laboratory Methods For The Investigation of Gas Hydrates  

Science.gov (United States)

Sediments in gas hydrate zones are complex composites of solid material and fluids. They may consist of unconsolidated sediments, gas hydrate, water or ice, and gas, depending on hydrostatic pressure and temperature, the sediment type, and genesis. Therefore, petrophysical properties as ultrasonic velocities and electrical resistivity, as well as porosity and permeability may vary within a broad range, and estimates of the gas content and models of gas hydrate deposits are very problematic. Evaluation methods for logging and geophysical field data in gas hydrate deposits are not yet available. This is due to the lack of laboratory measurements of physical pa- rameters in relation to the gas content and the sediment type. Standard interpretation methods have been applied with questionable success. Thus a transportable laboratory system (FLECAS: field laboratory experimental core analysis system) has been developed at the GFZ for the investigation of hydrate bear- ing cores. It consists of a thermostatted vessel (-10C to 60C) with pressure control (max. 70 MPa) and measurement setups for pore volume, sample volume, permeabil- ity, electrical resistivity, ultrasonic compressional and shear wave velocity. Measurements were done on synthetic gas hydrate bearing sands: During the temper- ature increase at first the frozen water melts, resulting in a decrease of resistivity and velocity. A further decrease in pressure causes the hydrate to dissociate, which tem- porarily decreases the temperature, and then again resistivity and velocity decrease, because water is released. At last the material looses its mechanical strength. Presently the system is used for core analysis of naturally occurring gas hydrates in the permafrost region at the Mallik gas hydrate production test well in Canada.

Kulenkampff, J.; Spangenberg, E.

41

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

42

Experimental investigations of a liquid desiccant absorber  

Energy Technology Data Exchange (ETDEWEB)

A cross-flow internally-cooled plate-type heat and mass exchanger is developed and examined experimentally as a dehumidifier in a liquid desiccant system. The sorbent used is lithium chloride (LiCl). The dehumidifier utilizes novel components and ideas in order to overcome the present obstacles such as the carryover of the sorbent into the air stream and the flow mal distribution of the sorbent over the exposed surfaces. The moisture removal rate was evaluated. The effects of the dehumidifier inlet parameters, including desiccant and water flow rates, air inlet temperature and humidity ratio were investigated. The air outlet temperature and humidity ratio were studied as a function of cooling water flow rate. The experimental results of the supply air adiabatic dehumidification show a consistent reduction in the air humidity ratio {Delta}{omega} in the range of 1.5 to 4.8 g/kg, an increase in the air temperature {Delta}T in the range of 3 to 7 K and a reduction in the LiCl solution mass fraction {Delta}{xi} in the range of 0.01 to 0.05 kg/kg. The experimental results of non-adiabatic dehumidification with internal cooling show a reduction in the air humidity ratio {Delta}{omega} of about 6 g/kg, a decrease in the air temperature {Delta}T in the range of 0.5 to 3.5 K and a reduction in the LiCl solution mass fraction {Delta}{xi} of about 0.06 kg/kg. (orig.)

Jaradat, Mustafa; Muetzel, Martin; Schiemann, Lars; Vajen, Klaus; Jordan, Ulrike [Kassel Univ. (Germany). Fachgebiet Solar- und Anlagentechnik

2012-07-01

43

Experimental investigation on lithium borohydride hydrolysis  

Energy Technology Data Exchange (ETDEWEB)

Lithium borohydride, one of the highest energy density chemical energy carriers, is considered as an attractive potential hydrogen storage material due to its high gravimetric hydrogen density (19.6%). Belonging to borohydride compounds, it presents a real issue to overcome aims fixed by the U.S. Department of Energy in the field of energy, and so crystallizes currently attention and effort to use this material for large scale civil and military applications. However, due to its important hygroscopicity, lithium borohydride is a hazardous material which requires specific handling conditions for industrial aspects. In order to understand much more the reaction mechanism involved between LiBH{sub 4} and the water vapor which leads to the native material dehydrogenation, several experimental techniques such as X-ray Photoelectrons Spectroscopy (XPS), Raman spectroscopy, X-Ray Diffraction (XRD) or thermal analysis (TGA/DTA) were investigated. Indeed, depending on water stoichiometric coefficient, several reactions are suggested in literature but the lithium borohydride hydrolysis way reaction scheme is still uncertain. Investigations exhibited interesting results and, highlighted the formation of lithium metaborate dihydrate LiBO{sub 2},2H{sub 2}O as hydrolysis product via such a solid-gas reaction. (author)

Goudon, J.P. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); SNPE Materiaux Energetiques, Centre de Recherches du Bouchet, Laboratoire BCFB, 9 rue Lavoisier, 91710 Vert-le-Petit (France); Bernard, F. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Renouard, J.; Yvart, P. [SNPE Materiaux Energetiques, Centre de Recherches du Bouchet, Laboratoire BCFB, 9 rue Lavoisier, 91710 Vert-le-Petit (France)

2010-10-15

44

Experimental investigation of creep behavior of reactor vessel lower head  

International Nuclear Information System (INIS)

The objective of the USNRC supported Lower Head Failure (LHF) Experiment Program at Sandia National Laboratories is to experimentally investigate and characterize the failure of the reactor pressure vessel (RPV) lower head due to the thermal and pressure loads of a severe accident. The experimental program is complemented by a modeling program focused on the development of a constitutive formulation for use in standard finite element structure mechanics codes. The problem is of importance because: lower head failure defines the initial conditions of all ex-vessel events; the inability of state-of-the-art models to simulate the result of the TMI-II accident (Stickler, et al. 1993); and TMI-II results suggest the possibility of in-vessel cooling, and creep deformation may be a precursor to water ingression leading to in-vessel cooling

45

Experimental investigation on granite emplacement during shortening  

Science.gov (United States)

We present analogue experiments performed to investigate the emplacement of granitic plutons in a shortening upper crust. The models were made of quartz-sand to simulate the brittle crust and a low-viscosity mixture of silicone and oleic acid to reproduce granitic magmas. Shortening of the models was obtained by a moving wall while a special injection apparatus allowed syn-kinematic magma intrusion from the base of the models. Experimental results show that: (1) space for intrusions is achieved during the movement along thrust faults and mostly coincides with low-pressure areas developed into the thrust-anticlines; (2) intrusion shapes are strictly dependent upon the competition between shortening rate (Sh) and injection rate (Inj). For high Sh/Inj values, plutons were elongated with the long axis parallel to the thrust surfaces; (3) magma migrates horizontally away from the injection point and towards the external sector in the direction of tectonic transport a longer distance for high Sh/Inj values; (4) syn-kinematic emplacement is also controlled by model thickness; an increase in this parameter results in an increase in the pluton plan-view aspect ratio. These results support that the final shape of orogenic plutons emplaced at shallow crustal levels may be strongly controlled by deformational features.

Montanari, Domenico; Corti, Giacomo; Sani, Federico; Del Ventisette, Chiara; Bonini, Marco; Moratti, Giovanna

2010-03-01

46

EXPERIMENTAL MODEL TO INVESTIGATE DRUGS FOR EPILEPSY  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction.Epilepsy is one of the most common neurological disorders characterized by seizures. Epileptic seizures result from excessive, abnormal, or hyper synchronous neuronal activity in the brain. It is a public health problem that is not yet curable but which can be controlled. A high percentage of patients who suffer from epilepsy do not have seizures control even when using the existing treatments. Therefore, an experimental study was conducted with the objective of determining the effect of the Bufo-toxin in rats belonging to the BALB/c and the Wistar strainsin order to diagnose the group of symptoms that confer lethality to this toxin and which can work as a treatment to such disease.Methodology the bufo-toxin was obtained from toads, then it was placedin alcoholic solution and it was applied to the rats in doses of 5 by 5 for up to 20 Units with an insulin syringe though the intramuscular via. Observations were registered and when the rats died a post-mortem examination was conducted in order to describe the effect of the toxin in the internal organs. Results. The rats that were inoculated within 20 units of the toxin showed epileptic seizures and finally cerebral spill or heart attack. Discussion and conclusion. This model can be used to investigate on useful drugs against epilepsy and even heart diseases, such as, hypertension andheart attacks.

Jesús Carlos Ruvalcaba Ledezma

2013-09-01

47

Experimental investigation of ram accelerator propulsion modes  

Science.gov (United States)

Experimental investigations on the propulsive modes of the ram accelerator are reviewed in this paper. The ram accelerator is a ramjet-in-tube projectile accelerator whose principle of operation is similar to that of a supersonic air-breathing ramjet. The projectile resembles the centerbody of a ramjet and travels through a stationary tube filled with a premixed gaseous fuel and oxidizer mixture. The combustion process travels with the projectile, generating a pressure distribution which produces forward thrust on the projectile. Several modes of ram accelerator operation are possible which are distinguished by their operating velocity range and the manner in which the combustion process is initiated and stabilized. Propulsive cycles utilizing subsonic, thermally choked combustion theoretically allow projectiles to be accelerated to the Chapman-Jouguet(C-J) detonation speed of a gaseous propellant mixture. In the superdetonative velocity range, the projectile is accelerated while always traveling faster than the C-J speed, and in the transdetonative regime (85 115 % of C-J speed) the projectile makes a smooth transition from a subdetonative to a superdetonative propulsive mode. This paper examines operation in these three regimes of flow using methane and ethylene based propellant mixtures in a 16 m long, 38 mm bore ram accelerator using 45 90 g projectiles at velocities up to 2500 m/s.

Hertzberg, A.; Bruckner, A. P.; Knowlen, C.

1991-03-01

48

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)

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 Ejecta Emplacement on Mars  

Science.gov (United States)

We present new laboratory data on ejecta emplacement using the JHU/APL ejecta simulator (EEsim). The EEsim is a large apparatus, capable of throwing sheets of debris with velocity and mass distributions analogous to ejecta from impacts.

Barnouin, O. S.; Ernst, C. M.; Wada, K.

2011-03-01

51

An Investigative, Cooperative Learning Approach to the General Microbiology Laboratory  

Science.gov (United States)

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…

Seifert, Kyle; Fenster, Amy; Dilts, Judith A.; Temple, Louise

2009-01-01

52

Laboratory investigation of steam adsorption in geothermal reservoir rocks  

Energy Technology Data Exchange (ETDEWEB)

Some vapor-dominated geothermal reservoirs and low-permeability gas reservoirs exhibit anomalous behavior that may be caused by surface adsorption. For example, geothermal reservoirs in the Larderello are of Italy and reservoirs in the Geysers Geothermal Field, California produce little, if any, liquid. Yet to satisfy material balance constraints, another phase besides steam must be present. If steam adsorption occurring in significant amounts is not accounted for, the reserves will be grossly under-estimated. In addition, well tests may be misinterpreted because the pressure response is delayed owing to be adsorbed material leaving or entering the gaseous phase. In the present research the role of adsorption in geothermal reservoirs in investigated. Two sets of laboratory equipment were constructed to measure adsorption isotherms of cores from Berea sandstone, Larderello, and The Geysers. Seven experimental runs were completed using nitrogen on the low temperature apparatus at -196/sup 0/C. Eight runs were conducted using steam on the high temperature apparatus at temperatures ranging from 150 C to 207/sup 0/C. The largest specific surface area and the greatest nitrogen adsorption isotherm were measured on the Berea sandstone, followed by a core from Larderello and then The Geysers. Difficulties in determining whether a system had reached equilibrium at the end of each step lead to questions regarding the magnitude of adsorption measured by the steam runs. Nevertheless, adsorption was observed and the difficulties themselves were useful indicators of needed future research.

Luetkehans, J.

1988-02-01

53

Laboratory investigation of novel oil recovery method for carbonate reservoirs  

Energy Technology Data Exchange (ETDEWEB)

This paper described a core flooding laboratory study conducted using composite rock samples from a carbonate reservoir. The aim of the study was to investigate the impact of salinity and ionic composition on oil, brine and rock interactions. Experimental parameters and procedures were designed to replicate reservoir conditions and current field injection practices. Results of the study demonstrated that alterations in the salinity and ionic composition of injected water can have a significant impact on the wettability of the rock surface. Nuclear magnetic resonance (NMR) studies confirmed that injecting different salinity slugs of seawater in carbonate core samples can cause a significant alteration in the surface charges of the rock, and lead to increased interactions with water molecules. The constant reduction of pressure drop across the composite cores with the injection of different diluted versions of water also provided proof of brine, oil and rock alterations. Results of the study indicated that the driving mechanism for waterflooding recovery processes is wettability alteration, which can be triggered by alterations in carbonate rock surface charges, and improvements in the connectivity between rock pore systems that coexist in carbonate rock samples. 41 refs., 8 tabs., 16 figs.

Yousef, A.A.; Al-Saleh, S.; Al-Kaabi, A.; Al-Jawfi, M. [Saudi Aramco, Riyadh (Saudi Arabia)

2010-07-01

54

Investigation of Appropriate Refractory Material for Laboratory Electritic Resistrance Furnance  

OpenAIRE

There have been numerous efforts to increase the local content of furnaces; hence the choice of appropriate refractory material for lining of locally manufactured furnaces has remained a major concern. This research work investigates the choice of appropriate local refractory material for the lining of laboratory electric resistance furnace.Electric resistance furnaces are extensively used in the laboratory for heat treatment of metals and alloys. Refractory binders such as silicon carbide w...

Agboola, J. B.; Abubakre, O. K.

2009-01-01

55

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, 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)

56

An experimental investigation of screech noise generation  

Science.gov (United States)

The screech noise generation process from supersonic underexpanded jets, issuing from a sonic nozzle at pressure ratios of 2.4 and 3.3 (fully expanded Mach number, Mj=1.19 and 1.42), was investigated experimentally. The extremely detailed data provide a fresh, new look at the screech generation mechanism. Spark schlieren visualization at different phases of the screech cycle clearly shows the convection of the organized turbulent structures over a train of shock waves. The potential pressure field (hydrodynamic fluctuations) associated with the organized structures is fairly intense and extends outside the shear layer. The time evolution of the near-field pressure fluctuations was obtained from phase-averaged microphone measurements. Phase-matched combined views of schlieren photographs and pressure fluctuations show the sound generation process. The individual compression and rarefaction parts of the sound waves are found to be generated from similar hydrodynamic fluctuations. A partial interference between the upstream-propagating sound waves and the downstream-propagating hydrodynamic waves is found to be present along the jet boundary. The partial interference manifests itself as a standing wave in the root-mean-square pressure fluctuation data. The standing wavelength is found to be close to, but somewhat different from, the shock spacing. An outcome of the interference is a curious ‘pause and go’ motion of the sound waves along the jet periphery. Interestingly, a length scale identical to the standing wavelength is found to be present inside the jet shear layer. The coherent fluctuations and the convective velocity of the organized vortices are found to be modulated periodically, and the periodicity is found to match with the standing wavelength distance rather than the shock spacing. The reason for the appearance of this additional length scale, different from the shock spacing, could not be explained. Nevertheless, it is demonstrated that an exact screech frequency formula can be derived from the simple standing wave relationship. The exact relationship shows that the correct spacing between the sources, for a point source model similar to that of Powell (1953), should be a standing wavelength (not the shock spacing).

Panda, J.

1999-01-01

57

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

58

Experimental investigation of smoothing by spectral dispersion  

International Nuclear Information System (INIS)

Measurements of smoothing rates for smoothing by spectral dispersion (SSD) of high-power, solid-state laser beams used for inertial confinement fusion (ICF) research are reported. Smoothing rates were obtained from the intensity distributions of equivalent target plane images for laser pulses of varying duration. Simulations of the experimental data with the known properties of the phase plates and the frequency modulators are in good agreement with the experimental data. These results inspire confidence in extrapolating to higher bandwidths and other SSD configurations that may be suitable for ICF experiments and ultimately for direct-drive laser-fusion ignition. (c) 2000 Optical Society of America

59

RESULTS OF AUTOMOBILE BIOGAS ENGINE EXPERIMENTAL INVESTIGATION  

OpenAIRE

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.; Kabanov, O.; Prikhodkin, O.; Druzyanova, V.; Petrov, N.

2013-01-01

60

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

61

An Investigative, Cooperative Learning Approach to the General Microbiology Laboratory  

OpenAIRE

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...

Seifert, Kyle; Fenster, Amy; Dilts, Judith A.; Temple, Louise

2009-01-01

62

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

OpenAIRE

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...

Metian, Marc; Bustamante, Paco; Cosson, Richard; He?douin, Laetitia; Warnau, Michel

2008-01-01

63

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.

64

Experimental investigation of planar ion traps  

OpenAIRE

Chiaverini et al. [Quant. Inf. Comput. 5, 419 (2005)] recently suggested a linear Paul trap geometry for ion trap quantum computation that places all of the electrodes in a plane. Such planar ion traps are compatible with modern semiconductor fabrication techniques and can be scaled to make compact, many zone traps. In this paper we present an experimental realization of planar ion traps using electrodes on a printed circuit board to trap linear chains of tens of 0.44 micron...

Pearson, C. E.; Leibrandt, D. R.; Bakr, W. S.; Mallard, W. J.; Brown, K. R.; Chuang, I. L.

2005-01-01

65

An Experimental Investigation of XML Compression Tools  

OpenAIRE

This paper presents an extensive experimental study of the state-of-the-art of XML compression tools. The study reports the behavior of nine XML compressors using a large corpus of XML documents which covers the different natures and scales of XML documents. In addition to assessing and comparing the performance characteristics of the evaluated XML compression tools, the study tries to assess the effectiveness and practicality of using these tools in the real world. Finally,...

Sakr, Sherif

2008-01-01

66

Experimental Investigation of Cooling of Electronic Equipment  

OpenAIRE

Electronic systems cooling is an attractive research area in engineering. The aim of this research is to design vortex promoters for cooling of electronic equipment. Different shapes of vortex promoters are used in the experimental study for turbulent flow and the results are used to validate the results of a previous computational work performed by the authors. Another aim is to choose an appropriate promoter and promoter location which provides best turbulence effects and most effective coo...

Ece Ayli; Caner Turk; Selin Aradag

2013-01-01

67

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–? turbulencous 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.

68

High range electromagnetic fields. Experimental investigations  

International Nuclear Information System (INIS)

It has been often discussed on the health effects from the electromagnetic fields, and nowadays this theme is particularly controlled and studied by the research-workers. It needs to know what is the risk connected to the exposure to the electromagnetism during a short or a long quantity of time and what are the health pathologies caused by the continue exposure. On one hand the results from epidemiological research can not still define the effect of the dose, on the other hand the legislative frame is variously fragmented and based on cautious concepts. But in this work, under the collaboration of Energy Resources Laboratory in Lausanne and the Geo resources and Territory Department in Turin University, are presented the early results on the experiments got out on high frequency (950 MHZ) in order to give a contribution to the debate between the scientific community and the public opinion

69

Experimental and Theoretical Investigation of Correlating TOF-Camera Systems  

OpenAIRE

This thesis investigates Time-of-Flight (TOF) 3D imaging systems. A mathematical model is developed to predict the systematic errors and statistical uncertainties of such cameras. In order to determine the errors experimentally and to test the model, a custom experimental setup has been built for this work. Chapter 2 provides a detailed discussion of this experimental setup. Three camera systems are investigated experimentally: the PMD[vision] 19k, the SwissRanger SR-3000) and the Effector ...

Rapp, Holger

2007-01-01

70

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)

71

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

72

Experimental Investigation of Thrust Faults in Homalite  

Science.gov (United States)

A sound interplay between experimental observations and numerical simulations can reveal a much greater insight into a scientific problem than either methodology alone, where numerics may direct the next experiment or vise-versa. With this motivation, experiments are designed to study the ground motion of thrust faults near the fault trace and to compare with true-to-life numerical simulation results. Through the application of an external load with a press to a thin sheet of Homalite, a high-density polymer, and discharging a capacitor across a wire, slip is initiated along a carefully treated interface. Several key parameters such as the angle of the interface and the applied load may be varied to achieve fundamentally different wave phenomenon, namely a super shear or sub-Rayleigh event. Laser vibrometers are used to record the velocity normal to the free surface on the hanging wall and the footwall. With high-speed cameras, photoelastic fringes are obtained in transmission through the Homalite slab, outputting information about the stress state in the material. Discoveries on the material response to the applied wave field are possible with the information from the photoelastic images in conjunction with the velocity traces, especially in the differences between a super shear and a sub Rayleigh event. Experimental results validate the salient features of the numerical simulations in 2D and even more closely in 3D.

Gabuchian, V.; Rosakis, A.; Lapusta, N.; Oglesby, D. D.

2010-12-01

73

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

74

Investigation of Appropriate Refractory Material for Laboratory Electritic Resistrance Furnance  

Directory of Open Access Journals (Sweden)

Full Text Available There have been numerous efforts to increase the local content of furnaces; hence the choice of appropriate refractory material for lining of locally manufactured furnaces has remained a major concern. This research work investigates the choice of appropriate local refractory material for the lining of laboratory electric resistance furnace.Electric resistance furnaces are extensively used in the laboratory for heat treatment of metals and alloys. Refractory binders such as silicon carbide were experimented upon for strength and resistance to high temperature.The results obtained showed that Kankara fireclay containing 15% SiC ( 5.70 % linear shrinkage , 46.2% apparent porosity, 1.77gkm³ Bulk density, 18 cycles of spalling tests at 1300°C, 5.253KN/m² of cold strength has appropriate properties for producing grooved bricks for lining of laboratory electric resistance Furnace.

J.B Agboola

2009-07-01

75

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

76

On-site laboratory support of the Oak Ridge National Laboratory remedial investigation/feasibility study  

International Nuclear Information System (INIS)

In 1987, a remedial investigation/feasibility study (RI/FS) was begun at Oak Ridge National Laboratory (ORNL). ORNL had established a number of waste area groupings (WAGs), each of which was to be studied and characterized separately. Although the nature and extent of contamination at the WAGs vary widely, samples from each WAG might be radiologically and/or chemically contaminated. To comply with Department of Transportation (DOT) regulations regarding the shipment of hazardous and radioactive materials, all samples are screened for radioactivity before shipment to independent laboratories for further analysis. In 1989 a Close Support Laboratory (CSL) was established at the RI/FS Field Operations Facility at ORNL. The CSL began as a screening facility and has evolved into a laboratory where high-quality analytical results on a number of different parameters are usually available within 24 hours of sampling. CSL capabilities include three basic areas: radiochemistry, volatile organic analysis (VOA), and wet chemistry

77

Experimental and Theoretical Investigations of Wet Flue Gas Desulphurisation  

DEFF Research Database (Denmark)

This thesis describes experimental and theoretical investigations of wet flue gas desulphurisa-tion (FGD). A review of the current knowledge of the various rate determining steps in wet FGD plants is presented. The experimental work covers laboratory studies as well as pilot- and full-scale experiments. In the theoretical part of the work, the laboratory and pilot plant observations are investigated using mathematical modelling.The mechanism underlying the rate of dissolution of finely grinded limestone particles was examined in a laboratory batch apparatus using acid titration. Three Danish limestones of dif-ferent origin were tested. A transient, mass transport controlled, mathematical model was de-veloped to describe the dissolution process. Model predictions were found to be qualitatively in good agreement with experimental data. Deviations between measurements and simulations were attributed primarily to the particle size distribution (PSD) measurements of the limestone particles, which were used as model inputs. The measured PSD was probably not representa-tive of a given limestone sample because of agglomeration phenomena taking place in the dis-perser, preventing a stable and accurate measurement. Other factors, such as convective mass transfer, porosity and porosity changes, and perhaps surface reaction, may also influence the rate of dissolution. However, those effects could not, due to the uncertainty of the PSD, be confirmed. Empirical correlations for the dimensionless mass transfer coefficients in a pilot plant (falling- film column) were determined. The correlations are valid at gas phase Reynolds numbers from 7500 to 18,300 and liquid phase Reynolds numbers from 4000 to 12,000, conditions of industrial relevance. The presence of inert particles in the liquid phase was found to decrease the rate of gas phase mass transport with up to 15 %, though the effect could not be correlated.A detailed model for a wet FGD pilot plant, based on the falling film principle, was devel-oped. All important rate determining steps, absorption of SO2, oxidation of HSO3-, dissolution of limestone, and crystallisation of gypsum were included. Model predictions were compared to experimental data such as gas phase concentration profiles of SO2, slurry pH-profiles, sol-ids contents of the slurry, liquid phase concentrations, and residual limestone in the gypsum. Simulations were found to match experimental data for the two Danish limestone types (Faxe Bryozo and a chalk, Mikrovit) investigated. Gas phase mass transport was found to be the dominating rate determining step, though the liquid phase mass transport resistance could not be neglected. Simulations and experimental data both showed the same degree of desulphuri-sation and absorber pH profile for the two limestone types using a holding tank pH of 5.5, but the residual limestone in the gypsum was significantly lower for the chalk. Furthermore, simulations showed that between 10 and 30 % of the limestone dissolves in the absorber de-pending on the process conditions. A typical holding tank pH of 5-5.5 (also used in full-scale wet FGD packed towers) was found to be a reasonable compromise between residual lime-stone in the gypsum and the degree of desulphurisation. Simulations were only slightly sensi-tive to the temperature in the interval 313 - 333 K, pertinent for full-scale wet FGD packed towers. The possibility of co-firing straw and coal was investigated in a full-scale power plant. No ef-fects on the overall performance of the wet FGD plant were observed, though laboratory ex-periments with fine dust and fly ash from the full-scale experiments showed a decrease in limestone reactivity. However, the test period was only about one week, probably not allowing the FGD plant to reach steady state operation. Pilot-scale experiments were initiated to investigate the possibility of oxidising spray dry scrubber by-products (TASP) to gypsum in wet FGD plants. The investigations showed that it was possible to oxidise the TASP at concentrations of up to 300 g/litre (feed tank basis

Kiil, SØren

1998-01-01

78

[Experimental model of orthotopic uterus transplantation in the laboratory rat].  

Science.gov (United States)

This study develops and standardizes an experimental model of uterus transplantation in the laboratory rat. Twelve orthotropic uterus transplantation were done. Animals were randomized in three groups. Postoperative survival was 100% and 75% at 72 hours. Recipients were euthanased at 24 hours, 48 hours and 72 hours and the grafts were harvested. Patency of the microsurgical anastomoses was 100% at 24 hours, 63% at 48 hours and 0% at 72 hours. The explanted uterine grafts were fixed in formalize and analyzed under light microscopy. The acute allograft rejection starts during the second day after transplantation. In additional dissection, anatomy of the pelvic region with regard to the topography of the uterus, tube and ovarian vessels was studied. This model of uterus transplantation in rats proposes a standardized tool for further research regarding cellular mechanisms of the acute allograft rejection and, for future, pregnancy of the transplanted uterus. PMID:12731229

Ionac, M; Jiga, L; Motoc, A; Lupu, C; Bordo?, D

2002-01-01

79

An experimental investigation of wind turbine wakes  

OpenAIRE

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...

Blomhoff, Hedda Paulsen

2012-01-01

80

Experimental Investigation of Centrifugal Compressor Stabilization Techniques  

Science.gov (United States)

Results from a series of experiments to investigate techniques for extending the stable flow range of a centrifugal compressor are reported. The research was conducted in a high-speed centrifugal compressor at the NASA Glenn Research Center. The stabilizing effect of steadily flowing air-streams injected into the vaneless region of a vane-island diffuser through the shroud surface is described. Parametric variations of injection angle, injection flow rate, number of injectors, injector spacing, and injection versus bleed were investigated for a range of impeller speeds and tip clearances. Both the compressor discharge and an external source were used for the injection air supply. The stabilizing effect of flow obstructions created by tubes that were inserted into the diffuser vaneless space through the shroud was also investigated. Tube immersion into the vaneless space was varied in the flow obstruction experiments. Results from testing done at impeller design speed and tip clearance are presented. Surge margin improved by 1.7 points using injection air that was supplied from within the compressor. Externally supplied injection air was used to return the compressor to stable operation after being throttled into surge. The tubes, which were capped to prevent mass flux, provided 9.3 points of additional surge margin over the baseline surge margin of 11.7 points.

Skoch, Gary J.

2003-01-01

81

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; Morosi, Stefano

2012-01-01

82

Flood Water Crossing: Laboratory Model Investigations for Water Velocity Reductions  

Directory of Open Access Journals (Sweden)

Full Text Available The occurrence of floods may give a negative impact towards road traffic in terms of difficulties in mobilizing traffic as well as causing damage to the vehicles, which later cause them to be stuck in the traffic and trigger traffic problems. The high velocity of water flows occur when there is no existence of objects capable of diffusing the water velocity on the road surface. The shape, orientation and size of the object to be placed beside the road as a diffuser are important for the effective flow attenuation of water. In order to investigate the water flow, a laboratory experiment was set up and models were constructed to study the flow velocity reduction. The velocity of water before and after passing through the diffuser objects was investigated. This paper focuses on laboratory experiments to determine the flow velocity of the water using sensors before and after passing through two best diffuser objects chosen from a previous flow pattern experiment.

Kasnon N.

2014-01-01

83

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

84

Experimental Investigation of Using Fuel Additives - Alcohol  

OpenAIRE

This research presents an investigation of the effects of ethanol addition to low octane numbergasoline, on the fuel octane number and on the performance of the engine. In this study, the tested gasoline(octane number = 90) is blended with five different percentages of ethanol, namely 3, 6, 9, 12 and 15% onvolume basis. Then these fuel blends, as well as the base gasoline fuel, w ere burnt in the tested engine. It isfound that the octane number of gasoline increases continuously and linearly ...

Fayyad, S. M.

2010-01-01

85

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

86

Experimental investigation of planar ion traps  

CERN Document Server

Chiaverini et al. [Quant. Inf. Comput. 5, 419 (2005)] recently suggested a linear Paul trap geometry for ion trap quantum computation that places all of the electrodes in a plane. Such planar ion traps are compatible with modern semiconductor fabrication techniques and can be scaled to make compact, many zone traps. In this paper we present an experimental realization of planar ion traps using electrodes on a printed circuit board to trap linear chains of tens of 0.44 micron diameter charged particles in a vacuum of 15 Pa (0.1 torr). With these traps we address concerns about the low trap depth of planar ion traps and develop control electrode layouts for moving ions between trap zones without facing some of the technical difficulties involved in an atomic ion trap experiment. Specifically, we use a trap with 36 zones (77 electrodes) arranged in a cross to demonstrate loading from a traditional four rod linear Paul trap, linear ion movement, splitting and joining of ion chains, and movement of ions through in...

Pearson, C E; Brown, K R; Chuang, I L; Leibrandt, D R; Mallard, W J

2005-01-01

87

Experimental investigation of the role of ions in aerosol nucleation  

DEFF Research Database (Denmark)

The role of ions in producing aerosols in Earth’s atmosphere is an area of very active research. Atmospheric (Clarke et al. 1998) and experimental (Berndt et al. 2005) observations have shown that the nucleation of aerosol particles can occur under conditions that cannot be explained by classical nucleation theory. Several ideas have been put forward to solve this nucleation problem, e.g. Ion-Induced Nucleation (Raes & Janssens 1985) and Ternary Nucleation (Kulmala et al. 2000). Experimental investigations exploring the role of ions in particle production are scarce, and often at conditions far removed from those relevant for the lower part of the atmosphere (Bricard et al. 1968). Recent experimental work (Svensmark et al. 2007) demonstrated that ions, produced by cosmic rays in the atmosphere, are likely to play an important role in the production of new aerosol particles. The mechanism whereby energetic cosmic rays can promote the production of cloud condensation nuclei at low altitudes constitutes a linkbetween cosmic rays and Earth's climate and there is thus a need to corroborate the results in a different experiment The present results are obtained in the same laboratory, but using a new setup The experiments were conducted in a 50 L cylindrical reaction chamber made of electropolished stainless steel. Aerosols were grown using photochemically produced sulphuric acid and ionization levels were controlled with a Cs-137 gamma-source. An increase in nucleation was observed when the chamber was exposed to the radioactive source. The results were analyzed using a model based on the General Dynamic Equation and the analysis revealed that Ion Induced Nucleation is the most likely mechanism for the observed nucleation increases and thus confirm the previous results.

Enghoff, Martin Andreas BØdker

88

The experimental investigation of concrete carbonation depth  

International Nuclear Information System (INIS)

Phenolphthalein indicator has traditionally been used to determine the depth of carbonation in concrete. This investigation uses the thermalgravimetric analysis (TGA) method, which tests the concentration distribution of Ca(OH)2 and CaCO3, while the X-ray diffraction analysis (XRDA) tests the intensity distribution of Ca(OH)2 and CaCO3. The Fourier transformation infrared spectroscopy (FTIR) test method detects the presence of C-O in concrete samples as a basis for determining the presence of CaCO3. Concrete specimens were prepared and subjected to accelerated carbonation under conditions of 23 deg. C temperature, 70% RH and 20% concentration of CO2. The test results of TGA and XRDA indicate that there exist a sharp carbonation front. Three zones of carbonation were identified according to the degree of carbonation and pH in the pore solutions. The TGA, XRDA and FTIR results showed the depth of carbonation front is twice of that determined from phenolphthalein indicator

89

Laboratory Investigation of Whistler and Lower Hybrid Wave Propagation  

Science.gov (United States)

An experimental investigation of the generation and propagation of waves on the whistler/lower hybrid branch is underway in the NRL Space Physics Simulation Chamber. The plasma conditions have been scaled to the inner magnetosphere. These studies are carried out in both homogeneous plasma and plasma containing density structuring. In homogeneous plasma, resonance cone propagation of the waves is observed, consistent with theoretical predictions. In plasma containing a density depletion layer, wave ducting within the layer has been observed. Experimental results on the observed whistler/lower hybrid wave propagation characteristics will be presented.

Amatucci, B.; Blackwell, D.; Ganguli, G.; Gatling, G.; Cothran, C. D.; Walker, D.

2009-11-01

90

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 deformatiling 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

91

Laboratory and numerical investigations of air sparging using MTBE as a tracer  

OpenAIRE

Air sparging experiments were conducted in a laboratory column to investigate air now and mass transfer behavior in different types of sand at different air injection rates. Methyl tertiary butyl ether (MTBE) was applied as a tracer, and by measuring the volatilization and the mean air content during the experiments, the air flow pattern and its influence on mass transfer were assessed. The experimental results showed large differences among the sand types. In fine sand, the mean air content ...

Mortensen, A. P.; Jensen, Karsten Høgh; Sonnenborg, T. O.; Arvin, E.

2006-01-01

92

Experimental and numerical investigation of the stability of overhanging riverbanks  

Science.gov (United States)

Although different types of riverbank mass failure have been studied by many researchers, many uncertainties remain in predicting cantilever failures, in part because of a lack of detailed observations of this type of bank collapse. In this study, a laboratory study of cantilever failure was carried out using two types of materials to form overhanging banks with three different densities. The laboratory results show that the occurrence of toppling failures is more probable than the simple shear-type mechanism that has been analyzed most frequently by prior researchers. We go on to model these toppling failures numerically. Specifically, a Mohr-Coulomb model, within the framework of SIGMA/W software (ver. 7.17), was used to simulate the stress-strain behavior of the experimental banks. The numerical results for loess materials are in good agreement with the laboratory observations, but the simulations do not replicate experimental failures observed in higher density, more cohesive soils.

Samadi, A.; Amiri-Tokaldany, E.; Davoudi, M. H.; Darby, S. E.

2013-02-01

93

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

94

Reduction of friction in fluid transport: experimental investigation  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish 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 mas efectiva (es posible obtener reducciones de hasta un factor de 8 en los coeficientes de fricción en segm [...] entos 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 propositos 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 fluidos no-Newtonianos, reología, y transferencia de calor en la UCSB. Abstract in english Drag reduction (DR) by the use of polymer and surfactant solutions is by far the most effective drag-reducing technique for turbulent flows (up to 8-fold reduction in friction coefficients is possible on straight pipes). From a fundamental point of view, the study of the DR phenomenon offers an oppo [...] rtunity for a better understanding of turbulence in general; from a practical point of view, DR can be used to save pumping power. Commercial implementation of drag-reducing fluids has proved successful for oil pipeline transportation, and looks promising for many other applications that are still under investigation, e.g. district heating or cooling systems, hydronic systems in buildings, sewers, irrigation, industrial processes, etc. Our efforts have focused on two main areas: (A) experimental research on momentum and heat transfer of turbulent flows of drag-reducing solutions, and (B) implementation of these solutions in hydronic cooling systems in buildings for energy conservation purposes. This paper describes an overview of the typical experimental research that we conduct in our non-Newtonian fluid mechanics, rheology, and heat transfer laboratory at UCSB.

G., Aguilar; K., Gasljevic; E.F., Matthys.

2006-10-01

95

Laboratory investigation of whistler and lower hybrid wave characteristics  

Science.gov (United States)

An experimental investigation of the generation and propagation of whistler and lower hybrid waves is underway in the NRL Space Physics Simulation Chamber. Wave propagation is being investigated in conditions simulating the Earth's radiation belt environment. These studies are carried out in both homogeneous plasma and plasma containing density structures. In homogeneous plasma, resonance cone propagation of the waves is observed, consistent with theoretical predictions. In plasma containing a density depletion layer, wave ducting within the layer has been observed. For these experiments, we have fabricated and tested transmitting and receiving magnetic loop antennas and electric field dipole receiving antennas. Preliminary comparisons of the two antenna styles indicate that loop antennas couple significantly more wave power into the plasma. Efforts are currently underway to further quantify these observations. Experimental results related to the propagation characteristics of whistler/lower hybrid waves under these conditions will be presented.

Amatucci, William; Blackwell, David; Ganguli, Gurudas; Gatling, George; Walker, David; Compton, Chris

2007-11-01

96

Experimental model of heterotopic uterus transplantation in the laboratory rat.  

Science.gov (United States)

The present study describes a standardized experimental model of whole-uterus-and-ovaries heterotopic allotransplantation in the laboratory rat. Fifteen transplantation procedures were done. The anatomy of the pelvic region was studied with an additional 20 dissections, noting the topographical and vascular anatomy of the uterus, fallopian tubes, and ovarian vessels. Recipients were randomized into three groups. The average operative time was 150 min. The postoperative survival rate was 100%. Postoperative vascular anastomosis patency was 100%, and 26% at 72 hr. Recipients were euthanized at 24 hr (group I), 48 hr (group II), and 72 hr (group III); grafts were harvested and examined macroscopically, and fixed in formaline for histopathological and immunocytochemical analysis. Failure in 74% of the grafts at 72 hr was due to early thrombosis, starting from the capillary bed and progressing towards the main feeding pedicles. More studies must be undertaken to further understand the rejection mechanisms in transplanted reproductive organs. The efficiency, feasibility, and safety for such an operation in humans remain to be proven. We consider the present model a suitable tool to study all the above-mentioned goals. PMID:12833326

Jiga, Lucian P; Lupu, C?t?lin M; Zoica, Bogdana S; Ionac, Mihai

2003-01-01

97

Diagnostic Protocol Used in Central Disease Investigation Laboratory Dhaka, Bangladesh  

OpenAIRE

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

98

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

99

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

OpenAIRE

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...

Tor Ivar Eikaas; Christian Schmid; Foss, Bjarne A.; Denis Gillet

2003-01-01

100

Laboratory Investigation of Relaxation Pathways for Vibrationally Excited OH  

Science.gov (United States)

The hydroxyl radical is a key species in the energy budget of the terrestrial atmospheres. In the Earth's upper atmosphere, vibrationally excited OH radicals (v ? 9) are formed by the H + O3 reaction. The non-thermal vibrational energy is either emitted as an infrared (IR) or visible photon, or converted into translational and internal energy via collisions with ambient gases. OH emission was recently reported for the first time in the nightglow of Venus [1]. Model calculations of the Mars airglow have also shown that the predicted intensity of the OH emission is extremely sensitive to the pathway of vibrational relaxation [2]. Accurate rate constant and mechanistic pathway information for the deactivation of the OH(v) states is essential in the modeling of both the atmospheric OH emission and the heating efficiency of the H + O3 reaction, as exemplified in our studies of vibrational relaxation for OH(v = 7, 9) by O, O2, N2, and CO2 [3,4]. We have initiated a research program to investigate the key pathways involved in OH(v) vibrational relaxation and their dependence on the collider species and temperature. In the laboratory experiments, we probe the fraction of collisions that lead to single-quantum relaxation of OH(v = 8) to OH(v = 7) for different atmospheric colliders. We developed a three-laser approach using the following steps: (1) generation of OH(v ? 4) by the O(1D) + H2 reaction following ozone photolysis at 248 nm by an KrF excimer laser in a mixture containing nitrogen and hydrogen; (2) infrared overtone excitation of the OH(v = 4) radicals to v = 7 at 938 nm using a pulsed optical parametric oscillator system triggered when the v = 4 population is near maximum and; (3) detection of the OH(v = 7) population by laser-induced fluorescence using the B - X (0,7) band at 213 nm with a pulsed tunable dye laser timed in order to scan the delay with respect to the IR pump laser. We will present the experimental methodology and measurements on the relaxation of OH(v = 8) to OH(v = 7) by O atoms and CO2. Our measurements to date indicate that different collider gases favor distinct relaxation pathways: the single-quantum cascade branching ratio for collisions with CO2 is approximately 3 times larger than that for collisions with O atoms. We will also discuss the atmospheric implications of our results based on the most current modeling calculations. Research supported by NASA Geospace Science grants NNX08AM47G and NNX12AD09G. [1] Piccioni, G. et al., Astron. Astrophys. 483, L29-L33 (2008). [2] García Muñoz, A. et al., Icarus 176, 75-95 (2005). [3] Thiebaud, J., Kalogerakis, K.S., and Copeland, R.A., Fall AGU Meeting, Abstract SA43A-1752 (2010). [4] Kalogerakis, K.S., G.P. Smith, and R.A. Copeland, J. Geophys. Res. 116, D20307, 2011JD015734 (2011).

Kalogerakis, K. S.; Thiebaud, J.; Matsiev, D.; Copeland, R. A.

2012-04-01

101

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

102

Experimental and analytical investigation of Paks NPP building structures  

International Nuclear Information System (INIS)

The dynamic characteristics of WWER-440 NPP building structures were experimentally investigated using explosive techniques. The same characteristics were calculated analytically. The comparison of experimental and analytical results show the adequacy of the modeling of the structures and soil-structure interaction. (author)

103

An experimental investigation of untriggered film boiling collapse  

International Nuclear Information System (INIS)

Film boiling has been investigated in a stagnant pool, using polished brass or anodised aluminium alloy rods in water. Experimental boiling curves were obtained, and pronounced ripples on the vapour/liquid interface were photographed. A criterion for untriggered film boiling collapse is proposed, consistent with experimental results. Application of the results to molten fuel coolant interaction studies is discussed. (U.K.)

104

Experimental Investigation of High Frequency Plasma Oscillations Within Hall Thrusters  

OpenAIRE

An experimental setup has been developed to measure high frequency plasma oscillations within the acceleration channel of a laboratory Hall thruster. The plasma oscillations are measured with three Langmuir probes separated by small axial and azimuthal offsets. This configuration permits the oscillations to be correlated with direction and wave number. This work is motivated by the anomalous electron transport phenomena, as plasma instabilities may play a crucial role in this transport proces...

Knoll, Ak; Thomas, N.; Gascon, N.; Cappelli, M.

2006-01-01

105

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

106

Experimental investigation of atoms in crossed electric and magnetic fields  

International Nuclear Information System (INIS)

We report recent progress in our experimental investigation of high-lying Rydberg states of barium in crossed electric and magnetic fields. Through analysis of the nearest-neighbour level spacing statistics, we investigate the evolution of the electron dynamics as the electric field strength is increased

107

Experimental investigation of atoms in crossed electric and magnetic fields  

Energy Technology Data Exchange (ETDEWEB)

We report recent progress in our experimental investigation of high-lying Rydberg states of barium in crossed electric and magnetic fields. Through analysis of the nearest-neighbour level spacing statistics, we investigate the evolution of the electron dynamics as the electric field strength is increased.

Connerade, J-P; Hogan, S D; Abdulla, A M [Quantum Optics and Laser Science Group, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom)

2005-01-28

108

Theoretical and experimental investigation of n-butanol combustion  

OpenAIRE

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

109

Experimental investigation of polarisation rotation in semiconductor optical amplifiers  

OpenAIRE

An experimental study of polarisation rotation in a semiconductor optical amplifier is presented. Two techniques are used to investigate the gain and birefringence along the two eigenmodes of the component waveguide, with and without injection. The first investigation is based on the residual reflectivity of the facet mirrors. From the modulation depth of polarisation resolved spectra, the gain and the refractive indices of these modes are determined. The second investigation takes into accou...

Bradley, Louise; Kennedy, B. F.; Philippe, S.; Landais, P.; Soto, H.

2004-01-01

110

EXPERIMENTAL INVESTIGATION ON HIGH PERFORMANCE CONCRETE USING SILICAFUME AND FLYASH  

OpenAIRE

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

111

Investigation into stutter ratio variability between different laboratories.  

Science.gov (United States)

The determination of parameters such as stutter ratio is important to inform a laboratory's forensic DNA profile interpretation strategy. As part of a large data analysis project to implement a continuous model of DNA profile interpretation we analysed stutter ratio data from eight different forensic laboratories for the Promega PowerPlex(®) 21 multiplex. This allowed a comparison of inter laboratory variation. The maximum difference for any one laboratory from the average of the best fit determined by the model was 0.31%. These results indicate that stutter ratios calculated from samples analysed using the same profiling kit are not expected to differ between laboratories, even those using different capillary electrophoresis platforms. A common set of laboratory parameters are able to be generated and used for profile interpretation at all laboratories using the same multiplex and cycle number, potentially reducing the need for individual laboratories to determine stutter ratios. PMID:25082139

Bright, Jo-Anne; Curran, James M

2014-11-01

112

Investigation of Sulfate Attack by Experimental and Thermodynamic Means  

OpenAIRE

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...

Kunther, Wolfgang

2012-01-01

113

Experimental Investigation into Electrical Discharge Machining of Stainless Steel 304  

OpenAIRE

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

114

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

115

Russian fast research reactor BOR-60 reactor: Experimental investigations  

International Nuclear Information System (INIS)

Experimental fast reactor BOR-60 is one of the leading experimental facilities in Russia used to test a large of number fuel pins, fuel assemblies, and control rods of different designs, fuel compositions and structural materials. It is also widely used for trying out the elements of closed fuel cycle, transmutation of actinides and plutonium utilization. BOR-60 reactor and high-capacity experimental base available at RIAR allow various experimental investigations to be performed. Since the BOR-60 startup (in 1969), a large scope of experiments have been done at RIAR practically in all directions that are of interest for the nuclear power engineering and related areas of science and engineering. In addition, a wide experience has been gained in calculation support of experimental investigations. During its 40-year operation, the BOR-60 core underwent multiple changes. There were more than 120 micro-runs, each micro-run being a reactor state different from others. The experimental investigations performed in different periods of time may be of interest for a researcher. Results obtained at this reactor contributed greatly to the development of the nuclear power engineering and made a basis for a successful startup and operation of reactors BN-350 and BN-600 as well as for long and safe operation of BOR-60 itself. At present, both the reactor and experiment gained at it are widely used for justification of promising fast reactorss

116

Experimental investigation on thermal-barrier performance of ceramic coatings  

Energy Technology Data Exchange (ETDEWEB)

Thermal-barrier performance of composite air-cooled vanes with ceramic coatings in a highly-loaded transonic turbine has been experimentally investigated. Experimental results show that the average net thermal-barrier effectiveness on the middle section of the coated vane is 167K, but the net thermal-barrier effectiveness at some points are measured at 145-206K. The effects of gas temperature on thermal-barrier performance of ceramic coatings are also investigated. It is found that the performance is even better at a higher temperature or higher heat flux condition.

Deng, Huayu; Luo, Mingjun; Liu, Cunlu (Gas Turbine Establishment (China))

1989-10-01

117

Experimental investigations of overvoltages in neutral isolated networks  

Energy Technology Data Exchange (ETDEWEB)

For more than a decade, the Nikola Tesla Institute has worked intensively on experimental investigations of transient voltages and currents in neutral isolated networks, usually at 6 kV. The paper presents the results of investigations of overvoltages at the instant of appearance of an earth fault and during its interruption, the earth-fault currents and overvoltages during ferroresonance. Investigations were performed on cable station service networks in hydro- and thermal-power plants, industrial and similar installations in Yugoslavia. On the basis of these investigations, some measures are suggested for improving the reliability of operation of neutral isolated networks. (author)

Vukelja, P.I.; Naumov, R.M.; Vucinic, M.M.; Budisin, P.B. (Electrotechnicki Inst. ' Nikola Tesla' , Belgrade (Yugoslavia))

1993-09-01

118

An Inquiry-Based Density Laboratory for Teaching Experimental Error  

Science.gov (United States)

An inquiry-based laboratory exercise is described in which introductory chemistry students measure the density of water five times using either a beaker, a graduated cylinder, or a volumetric pipet. Students are also assigned to use one of two analytical balances, one of which is purposefully miscalibrated by 5%. Each group collects data using…

Prilliman, Stephen G.

2012-01-01

119

PLACE: An Open-Source Python Package for Laboratory Automation, Control, and Experimentation.  

Science.gov (United States)

In modern laboratories, software can drive the full experimental process from data acquisition to storage, processing, and analysis. The automation of laboratory data acquisition is an important consideration for every laboratory. When implementing a laboratory automation scheme, important parameters include its reliability, time to implement, adaptability, and compatibility with software used at other stages of experimentation. In this article, we present an open-source, flexible, and extensible Python package for Laboratory Automation, Control, and Experimentation (PLACE). The package uses modular organization and clear design principles; therefore, it can be easily customized or expanded to meet the needs of diverse laboratories. We discuss the organization of PLACE, data-handling considerations, and then present an example using PLACE for laser-ultrasound experiments. Finally, we demonstrate the seamless transition to post-processing and analysis with Python through the development of an analysis module for data produced by PLACE automation. PMID:25304874

Johnson, Jami L; Tom Wörden, Henrik; van Wijk, Kasper

2014-10-10

120

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

121

Laboratory investigations of arcing on W-coated graphite components  

Energy Technology Data Exchange (ETDEWEB)

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., E-mail: michael.laux@ipp.mpg.de [Teilinstitut Greifswald, Wendelsteinstr. 1, D-17491 Greifswald (Germany); Siemroth, P.; Marx, M. [Arc Precision Sources, Coatings and Analysis GmbH, Bahnhofstr. 1, D-15745 Wildau (Germany); Neu, R.; Rohde, V.; Balden, M.; Endstrasser, N. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)

2013-07-15

122

Experimental astrochemistry: from ground-based to space-borne laboratories (Foreword)  

Science.gov (United States)

The investigation of the origin and evolution of molecules in space environments, either in interstellar or interplanetary conditions, constitutes a topic of high importance in modern space sciences. The presence of diversified and complex molecules motivates astrochemists to explore their formation mechanisms along with the physical conditions ruling these physico-chemical processes. Beside theoretical approaches aiming at simulating these processes, experimental techniques are nowadays frequently applied. Both laboratory and space experiment projects allow to reproduce to some extent the adequate conditions to understand some of these processes. The most recent results based on these techniques, and the prospects for future investigations, including the use of space platforms, were the scientific motivation of this workshop. These proceedings summarize a part of the content of this workshop, including abundant references to the relevant bibliography.

De Becker, M.; Cottin, H.; Fleury-Frenette, K.; Habraken, S.

2015-01-01

123

Experimental and numerical investigation of one-dimensional waterflood in porous reservoir  

Energy Technology Data Exchange (ETDEWEB)

Experimental and numerical investigation of relative permeability and oil recovery from the porous reservoir are described for short and long core samples. The relative permeability ratios, which are function of water saturation, obtained from laboratory core flooding experiments have been used for prediction of oil recovery through numerical simulation of non-dimensional Buckley-Leverett equation. The simulation results for oil recovery compared well with recovery results obtained from core flooding experiments. (author)

Hadia, N.; Chaudhari, L.; Mitra, Sushanta K. [IITB-ONGC Joint Research Centre, and Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400 076 (India); Aggarwal, A.; Vinjamur, M. [IITB-ONGC Joint Research Centre, and Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400 076 (India); Singh, R. [IITB-ONGC Joint Research Centre, and Institute of Reservoir Studies, ONGC, Ahmedabad (India)

2007-11-15

124

Investigation of high purity beryllium for the International Thermonuclear Experimental Reactor (ITER), Task 002. Final report  

International Nuclear Information System (INIS)

The report includes a description of experimental abilities of Solid Structure Research Laboratory of IAE NNC RK, a results of microstructural characterization of A-4 grade polycrystal Beryllium produced at the Ulba metal plant and a technical project-for irradiation experiments. Technical project contains a detailed description of five proposed experiments, clearing behavior of Beryllium materials under the influence of irradiation, temperature, helium and hydrogen accumulation. Complex irradiation jobs, microstructural investigations and mechanical tests are planned in the framework of these experiments

125

Investigating the Site of Newton's Laboratory in Trinity College, Cambridge  

OpenAIRE

It is not generally known that over the course of some thirty years, Isaac Newton carried out around four hundred chemical experiments in a private laboratory located in the walled garden immediately below his rooms in Trinity College, Cambridge. The exact location of his laboratory has long been a source of conjecture and this article describes a survey undertaken to determine both the possible site of the laboratory as well as that of the rubbish pit in which ...

Spargo, P. E.

2005-01-01

126

Experimental econophysics properties and mechanisms of laboratory markets  

CERN Document Server

Experimental Econophysics describes the method of controlled human experiments, which is developed by physicists to study some problems in economics or finance, namely, stylized facts, fluctuation phenomena, herd behavior, contrarian behavior, hedge behavior, cooperation, business cycles, partial information, risk management, and stock prediction. Experimental econophysics together with empirical econophysics are two branches of the field of econophysics. The latter one has been extensively discussed in the existing books, while the former one has been seldom touched. In this book, the author will focus on the branch of experimental econophysics. Empirical econophysics is based on the analysis of data in real markets by using some statistical tools borrowed from traditional statistical physics. Differently, inspired by the role of controlled experiments and system modelling (for computer simulations and/or analytical theory) in developing modern physics, experimental econophysics specially relies on controlle...

Huang, Ji-Ping

2015-01-01

127

Experimental Investigation in Fluid Mechanics – Its Role, Problems and Tasks  

Directory of Open Access Journals (Sweden)

Full Text Available In this contribution, some problems and tasks of experimental fluid mechanics are presented. Paradoxes, basic laws and contemporary investigation approaches are discussed. Experimental results, together with theoretical knowledge and numerical simulations gradually form basis for solution of topical problems. The author of this contribution focuses his investigations into field of compressible fluid flow. Due to this, some results of high-speed aerodynamic research contributing to design and operation of machines, where flow velocities exceed speed of sound, are shown. Moreover, the author intends to show, that fluid mechanics is open field ready to describe complex interactions at fluid flows. Experimental fluid mechanics takes part in formulation and solution of tasks at flow field modelling, at explanation of phenomena taking place in nature and in technical works.

Šafa?ík P.

2013-04-01

128

Experimental Investigation of Forecasting Methods Based on Universal Measures  

OpenAIRE

We describe and experimentally investigate a method to construct forecasting algorithms for stationary and ergodic processes based on universal measures (or so-called universal data compressors). Using some geophysical and economical time series as examples, we show that the precision of thus obtained predictions is higher than that of known methods.

Ryabko, Boris; Pristavka, Pavel

2011-01-01

129

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

130

- 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.

Lic. Ileana Macías Hernández

2006-07-01

131

Experimental investigation of failure time prediction in landslides  

Science.gov (United States)

Many new landslides often originate in old landslide areas, on pre-existing slip surfaces at residual shear strength condition. Previous laboratory investigations of drained displacement rates with time for pre-sheared surfaces have been very limited. A detailed survey of the literature reveals that all of the laboratory constant load compression tests, and a significant number of slope movement records that have been interpreted, correspond to ground conditions in the range of fully softened to intact shear strength. In fact, a few researchers mentioned stress-controlled direct shear and ring shear devices; however, they didn't present detailed test results and interpretation. A new laboratory normal- and shear-load-controlled direct shear device was designed for observing the deformation-time behaviour of pre-sheared surfaces, under constant normal and shear load. Estimating time to failure of a landslide based on measured creep movements have been suggested by various researchers. Some of the failure forecasting tools suggested in the literature are: relationship between minimum displacement rate before acceleration and time to failure; plot of inverse of velocity with time; and plot of acceleration with time. Based on the laboratory creep deformation tests on pre-existing shear surfaces, it is observed that at any shear stress level, the logarithm of the displacement rate decreases linearly with increase in the logarithm of time (until it reaches a minimum rate and starts increasing). The slope of this relationship is more or less independent of the shear stress level. A plot of minimum displacement rate immediately before acceleration, and time to failure is presented together with Saito and Uezawa (1961) data. It is confirmed that the time to failure is inversely proportional to the minimum displacement rate preceding the acceleration to failure. Inverse of velocity, and acceleration are also used as prediction tools, as was also used by other researchers. In the laboratory tests carried out in this study, a peak is observed in the inverse velocity-time plots (corresponding to the minimum displacement rate before acceleration), and then the inverse velocity values decrease toward zero (linearly or asymptotically) indicating the failure time. Acceleration and time to failure values are presented together with previous researchers' data from landslide case histories. Although the laboratory values of time to failure are very small (in the range of 1 to 100 minutes) and may seem to have limited use for real-life prediction, the lab test results confirm a linear trendline between acceleration and time to failure. This study is an attempt to investigate possible use of such forecasting tools. Although there are limitations in this laboratory study, the results show potential for forecasting tools to be useful with more data.

Huvaj-Sarihan, Nejan

2010-05-01

132

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

International Nuclear Information System (INIS)

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.)

133

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

134

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

135

Numerical and experimental investigation of vortical flow-flame interaction  

Energy Technology Data Exchange (ETDEWEB)

A massively parallel coupled Eulerian-Lagrangian low Mach number reacting flow code is developed and used to study the structure and dynamics of a forced planar buoyant jet flame in two dimensions. The numerical construction uses a finite difference scheme with adaptive mesh refinement for solving the scalar conservation equations, and the vortex method for the momentum equations, with the necessary coupling terms. The numerical model construction is presented, along with computational issues regarding the parallel implementation. An experimental acoustically forced planar jet burner apparatus is also developed and used to study the velocity and scalar fields in this flow, and to provide useful data for validation of the computed jet. Burner design and laser diagnostic details are discussed, along with the measured laboratory jet flame dynamics. The computed reacting jet flow is also presented, with focus on both large-scale outer buoyant structures and the lifted flame stabilization dynamics. A triple flame structure is observed at the flame base in the computed flow, as is theoretically expected, but was not observable with present diagnostic techniques in the laboratory flame. Computed and experimental results are compared, along with implications for model improvements.

Najm, H.N.; Schefer, R.W.; Milne, R.B.; Mueller, C.J. [Sandia National Labs., Livermore, CA (United States); Devine, K.D.; Kempka, S.N. [Sandia National Labs., Albuquerque, NM (United States)

1998-02-01

136

Experimental Investigation of the Effectiveness of Various  Additives in Reducing Wind Erosion from Iron Ore Piles   

OpenAIRE

Background and Objectives: Wind-induced particulate air pollution from iron ore piles can causes environmental and economic problems for steel industries. In this experimental study, the effectiveness of various additives in reducing particulate air pollution from iron ore piles was investigated in a laboratory wind tunnel.Materials and Methods:  The experimental set up consisted of a prismatic pile and a wind tunnel. Four different wind speeds of 4.3, 5, 7 and 11 m/s was used in the study ...

Mohammad Sadegh Hassanvand; Ayoub Torkian; Mohammad Reza Sahebnasagh; Kazem Naddafi; Mohammad Kazem Moayyedi

2012-01-01

137

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 -5 md to 110 md, respectively. The lowest final porosity (0.05) and permeability (-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

138

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

139

Experimental investigation of electron channeling radiation in diamond crystal  

International Nuclear Information System (INIS)

New results on the experimental investigation of the electron in a diamond crystal, obtained at the Tomsk synchrotron, are presented. The experimental data are systematized in such a way that it allows observation of a transition from axial to planar channeling and the variation of a maximum position in the radiation spectrum at planar channeling with the electron energy change. A comparison of the spectra of the coherent bremsstrahlung radiation and radiation at planar and axial channeling is performed, and the radiation losses in angular cone 1/? are obtained. (author)

140

Experimental and analytical investigation of rotor bearing systems  

OpenAIRE

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...

Ashtekar, Ankur

2012-01-01

141

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)

142

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.

143

Experimental Methods in Neuroscience: An Undergraduate Neuroscience Laboratory Course for Teaching Ethical Issues, Laboratory Techniques, Experimental Design, and Analysis  

OpenAIRE

We have developed and recently taught a 200 level undergraduate course entitled, ‘Experimental Methods in Neuroscience’. This is a required course in an increasingly popular Neuroscience major at Smith College. Students are introduced initially to issues of animal ethics and experimentation, and are familiarized with our Animal Care Facility. Using an open field and rotarod apparatus, and the elevated plus and Barnes mazes, they conduct behavioral testing of two strains of mice, C57/BL/6J...

Hall, Adam C.; Harrington, Mary E.

2003-01-01

144

Oak Ridge National Laboratory Research Reactor Experimenters' Guide  

International Nuclear Information System (INIS)

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

145

Experimental investigations of MHD flows in a sudden expansion  

International Nuclear Information System (INIS)

Reliable theories and models concerning MHD flows in manifolds for fusion applications are important, since most of the pressure drop occurs in those parts of the blanket. Abrupt changes of flow direction in feeding and draining lines as well as expansions and contractions cause flow redistribution and additional pressure drop. Numerical and asymptotic models have been developed during the last years, which require validation on the basis of precise experimental data. Since experimental results available in literature cover only the range of moderate magnetic fields, i.e. Ha < 300, and experiments in electrically conducting sudden expansions do not exist, the experimental data base has to be considerably extended in order to cover the fusion relevant range of parameters. For that reason a forced convective MHD experiment in a sudden expansion of rectangular ducts has been designed, manufactured and inserted into the liquid metal NaK-loop of the MEKKA laboratory at the Forschungszentrum Karlsruhe in the frame of the EFDA Technology Work Program TW2-TTBA-006a D1. Experiments have been performed in which the induced electric potential is measured on the surface of the expanding test section by more than 300 surface potential probes. The pressure variation along the duct has been measured at 16 different axial positions. For high interaction parameters the pressure measurements confirm the theoretical results obtained by an asymptotic theory valid for inertialess flows. Lotic theory valid for inertialess flows. Local quantities of the flow, e.g. potential gradients, are inferred with traversable probes at different locations in the ducts. A comparison of experimental and available theoretical results shows quite good agreement and confirms both the validity of the used theoretical tools and the good quality of the measurements. Moreover, due to its valuable contribution to the data base of fundamental MHD flows these experimental results may serve as benchmark basis for future developments of computational MHD tools. (orig.)

146

Experimental investigations of MHD flows in a sudden expansion  

Energy Technology Data Exchange (ETDEWEB)

Reliable theories and models concerning MHD flows in manifolds for fusion applications are important, since most of the pressure drop occurs in those parts of the blanket. Abrupt changes of flow direction in feeding and draining lines as well as expansions and contractions cause flow redistribution and additional pressure drop. Numerical and asymptotic models have been developed during the last years, which require validation on the basis of precise experimental data. Since experimental results available in literature cover only the range of moderate magnetic fields, i.e. Ha < 300, and experiments in electrically conducting sudden expansions do not exist, the experimental data base has to be considerably extended in order to cover the fusion relevant range of parameters. For that reason a forced convective MHD experiment in a sudden expansion of rectangular ducts has been designed, manufactured and inserted into the liquid metal NaK-loop of the MEKKA laboratory at the Forschungszentrum Karlsruhe in the frame of the EFDA Technology Work Program TW2-TTBA-006a D1. Experiments have been performed in which the induced electric potential is measured on the surface of the expanding test section by more than 300 surface potential probes. The pressure variation along the duct has been measured at 16 different axial positions. For high interaction parameters the pressure measurements confirm the theoretical results obtained by an asymptotic theory valid for inertialess flows. Local quantities of the flow, e.g. potential gradients, are inferred with traversable probes at different locations in the ducts. A comparison of experimental and available theoretical results shows quite good agreement and confirms both the validity of the used theoretical tools and the good quality of the measurements. Moreover, due to its valuable contribution to the data base of fundamental MHD flows these experimental results may serve as benchmark basis for future developments of computational MHD tools. (orig.)

Buehler, L.; Horanyi, S.

2006-08-15

147

Combined Numerical and Experimental Investigation of Progressive Failure of Composites  

CERN Document Server

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

148

Experimental techniques for the investigation of coupled phenomena in geomaterials  

Directory of Open Access Journals (Sweden)

Full Text Available The paper describes different experimental setups and techniques used to investigate coupled stress, fluid (water and air and temperature effects on geomaterials. Two temperature controlled cells are described: a a constant volume cell in which thermal pulses can be performed under controlled hydraulic conditions to induce pore pressure build-up during quasi-undrained heating and later dissipation; and b an axisymmetric triaxial cell with controlled suction and temperature to perform drained heating and cooling paths under partially saturated states. The paper also presents an experimental setup to perform controlled flow-rate gas injection experiments on argillaceous rocks using a high-pressure triaxial cell. This cell is used to study gas migration phenomena and the conditions under which gas breakthrough processes occur. Selected test results are presented, which show the capabilities of the different experimental setups described to capture main behavioural features.

Romero E.

2010-06-01

149

Experimental apparatus for tritium permeation studies in tritium process laboratory  

International Nuclear Information System (INIS)

An experimental apparatus has been developed to carry out tritium permeation experiments for candidate first-wall materials subjected to a high flux of low energy tritium ions, and installed in a glovebox. The experimental apparatus consists of five main systems; (1) a tritium ion source with energies variable from 20 to 1400 eV, (2) a main chamber system for direction an ion beam onto a heated target and for measuring various implantation-related experimental parameters by means of SIMS and AES, (3) a downstream system for measuring the permeated tritium through the target specimen by means of QMS, (4) a tritium supply and recovery system and (5) evacuation system. Operational tests with the system have yielded deuterium ion-beam with more than 90% deuterons and intensities from 2 x 1015 D+/cm2s at 200 eV to greater than 3 x 1015 D+/cm2s at 1000 eV. The energy width of the ion beam was about 10% of the beam energy ranging from 100 to 1400 eV. Baseline pressure as low as 9 x 0-9 Torr and 1 x 10-9 Torr have been achieved in the main chamber and downstream system, respectively

150

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

151

Experimental and numerical investigations of superplastic deformation mechanisms  

Energy Technology Data Exchange (ETDEWEB)

Experimental and numerical investigations of superplastic deformation are being carried out in order to understand the underlying mechanisms of deformation in low (conventional) and high strain-rate ranges. The experimental analysis consists of analyzing the microstructure using Backscattered Kikuchi Diffraction (BKD) method and relating it to the various mechanisms of superplastic deformation. The numerical investigation consists of developing a micromechanical model of superplastic deformation from the constituent grain level to the level of the polycrystalline aggregate. This model uses the self-consistent method to evaluate the grain to grain variation of stress during superplastic deformation. It is applied to statically recrystallized 7475 aluminum alloy and dynamically recrystallizing SUPRAL and the influence of temperature on the flow stress vs. strain rate behavior is successfully predicted. (orig.)

Chandra, N. [Dept. of Mechanical Engineering, Florida A and M Univ., Florida State Univ., Tallahassee, FL (United States); Murali, K. [Dept. of Mechanical Engineering, Florida A and M Univ., Florida State Univ., Tallahassee, FL (United States); Garmestani, H. [Dept. of Mechanical Engineering, Florida A and M Univ., Florida State Univ., Tallahassee, FL (United States)

1994-12-31

152

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-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.

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

1993-01-01

153

Experimental and theoretical investigation of film condensation with noncondensable gas  

Energy Technology Data Exchange (ETDEWEB)

Experimental and theoretical investigations were conducted for the film condensation with noncondensable gas in a vertical tube. Condensation experiments were performed for a steam-air mixture in a vertical tube submerged in a water pool where the heat from the condenser tube was removed through a boiling heat transfer. Degradation of the condensation with noncondensable gas was investigated. A heat and mass analogy model for the annular filmwise condensation with noncondensable gas was developed. In the steam-air mixture region, general momentum, heat and mass transport relations derived by analytic method were used with the consideration of surface suction effect. The predictions from the model were compared with the experimental data and the agreement was satisfactory. (author)

Oh, Seungmin; Revankar, Shripad T. [School of Nuclear Engineering, Purdue University West Lafayette, IN 47907 (United States)

2006-07-15

154

Experimental investigation of symmetry properties of second harmonic Lamb waves  

Science.gov (United States)

Recent studies by multiple authors show contradictory results concerning the symmetry properties of second harmonic Lamb waves. This research experimentally investigates this symmetry issue by examining both symmetric (s1-s2) and anti-symmetric (a1-a2 and a2-a4) mode pairs in aluminum plates under the same experimental conditions. The wedge technique is used to generate and detect ultrasonic Lamb wave signals of a specific mode, and the Morlet wavelet is applied to extract the fundamental and second harmonic amplitudes. The measured normalized second harmonic amplitudes of the three different mode pairs all show a linear increase with propagation distance. However, the slopes of the two anti-symmetric mode pairs are smaller by two to three orders of magnitude than that of the symmetric mode pair considered. Further investigations of these two anti-symmetric mode pairs for plates with different levels of material nonlinearity reveal consistently small slopes that are independent of the level of material nonlinearity. Therefore, this research experimentally demonstrates that the second harmonic generation in anti-symmetric Lamb wave modes is extremely inefficient; this result is consistent with some recent theoretical predictions and thus shows that the use of these anti-symmetric modes is not favorable for the experimental characterization of material nonlinearity.

Liu, Yu; Kim, Jin-Yeon; Jacobs, Laurence J.; Qu, Jianmin; Li, Zheng

2012-03-01

155

Experimental and computational investigation into race car mechanics  

OpenAIRE

In this study, experimental tests and Computational Fluid Dynamics are used to investigate the aerodynamic performance of two types of track-based racing cars. After the literature study, where automotive aerodynamics is discussed in very general terms, the air flow beneath a Formula One Grand Prix Racing Car is investigated. This is achieved by fitting the under-tray of a 30% scale model of the Parmalat Forti Ford FGO 1-95 with surface-static pressure ports and testing the model in a rolling...

Penning, Pieter Paulus

2006-01-01

156

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

157

Experimental Investigation On Design Of High Pressure Steam Turbine Blade  

OpenAIRE

The Experimental investigation on design of high pressure steam turbine blade addresses the issue of steam turbine efficiency. A specific focus on aerofoil profile for high pressure turbine blade, and it evaluates the effectiveness of certain Chromium and Nickel in resisting creep and fracture in turbine blades. The capable of thermal and chemical conditions in blade substrate from to prevent the corrosion when exposed to wet steam. The efficiency of the steam turbine is a key factor in both ...

Subramanyam Pavuluri, Dr A. Siva Kumar

2013-01-01

158

Experimental investigation of GTE-115 combustor with premixed burner unit  

Energy Technology Data Exchange (ETDEWEB)

The results of experimental investigation of the basic parameters of one-burner, 1/18 sector of a full-scale annular combustor of the Turboatom'' GTE-115 gas turbine unit are presented. Specifics of fuel burnup and formation of toxic pollutants in premixed combustion using a pilot diffusion burner are presented. Generalized dependences of combustor characteristics versus flow parameters and an optimized algorithm of combustor loading are illustrated.

Sokolov, K.Y.; Tumanovsky, A.G.; Gutnik, M.N.; Mechanikov, A.I. (All-Russian Heat Engineering Inst., Moscow (Russian Federation)); Reshitko, V.P.; Grinshtein, M.I. (Turbineworks Turboatom, Charkov (Ukraine))

1994-07-01

159

Contract design and insurance fraud : an experimental investigation  

OpenAIRE

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...

Lammers, Frauke; Schiller, Jo?rg

2010-01-01

160

Contract design and insurance fraud: An experimental investigation  

OpenAIRE

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...

Lammers, Frauke; Schiller, Jo?rg

2010-01-01

161

Evolution of dynamic fractures in PMMA : experimental and numerical investigations  

OpenAIRE

A combined experimental/numerical study has been conducted to investigate dynamic fractures in poly(methyl methacrylate) (PPMA). The results obtained from single-edge-notched-tensile (SENT) fracture tests support the idea that the evolution of fracture in PMMA is governed by nucleation, growth and coalescence of penny-shaped micro-cracks. The density of the microcracks and therefore the roughness of the fracture surface increase with the crack velocity. Both the surface roughness and the size...

Ivankovic, Alojz; Murphy, Neal; Hillmansen, S.

2004-01-01

162

Experimental and Numerical Investigation of Therapeutic Ultrasound Angioplasty  

OpenAIRE

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...

Gavin, Graham P.; Hashmi, M. S. J.; Mcguinness, Garrett B.

2005-01-01

163

Hydrogen gas explosions in pipelines, modeling and experimental investigations  

OpenAIRE

Gas explosions in closed pipes with a single obstacle have been investigated both numerically and experimentally. Most of the work is related to hydrogen and air mixtures, but other fuels have also been used. At the present time there does not exist a software tool or a numerical method that single-handedly can cover the whole range of phenomena in gas explosions. Computational fluid dynamics is also a developing ?eld, even for fluid flow without chemical reactions. The objective of this wo...

Knudsen, Vegeir

2006-01-01

164

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)

165

Experimental Investigation of a Wing-in-Ground Effect Craft  

OpenAIRE

The aerodynamic characteristics of the wing-in-ground effect (WIG) craft model that has a noble configuration of a compound wing was experimentally investigated and Universiti Teknologi Malaysia (UTM) wind tunnel with and without endplates. Lift and drag forces, pitching moment coefficients, and the centre of pressure were measured with respect to the ground clearance and the wing angle of attack. The ground effect and the existence of the endplates increase the wing lift-to-drag ratio at low...

Mobassher Tofa, M.; Adi Maimun; Ahmed, Yasser M.; Saeed Jamei; Agoes Priyanto; Rahimuddin

2014-01-01

166

Experimental investigation of external explosion in the venting process*  

OpenAIRE

Experimental investigations were conducted on the process of combustion and explosion vent in a 200 mm (diameter)×400 mm (length) vertical cylindrical vessel. When CH4-air mixture gases were used and the vent diameter was 55 mm, conditions of ? (equivalent ratio)=0.8, ?=1.0 and ?=1.3 and two ignition positions (at the cylinder center and bottom) were selected. The venting processes and the correlated factors are discussed in this paper.

Du, Zhi-min; Jin, Xin-qiao; Cui, Dong-ming; Ye, Jing-fang

2005-01-01

167

Assessment of experimental research techniques for the investigation of radionuclide migration in aquifers  

International Nuclear Information System (INIS)

The objectives of this work have been to contribute to a better understanding of the transport behaviour of the actinides using Eu as a homologue and, in addition, to compare the different laboratory techniques used in migration studies - batch, column and diffusion tests. The experimental work was focused on the radioisotopes of (Na), (Ca), Sr, Zr, (Nb), Tc, Eu and (Pu) and investigated the essential influences on the transport behaviour, exerted by redox conditions, the formation of complexes with natural humic acid as well as the formation and/or presence of colloids. Samples from the Gorleben and Drigg sites were investigated

168

Experimental Methods in Neuroscience: An Undergraduate Neuroscience Laboratory Course for Teaching Ethical Issues, Laboratory Techniques, Experimental Design, and Analysis  

Science.gov (United States)

This article describes the development of a course which introduces students to issues of animal ethics, experimentation, and an Animal Care Facility. The experiments enable the students to gain confidence in collecting data, compiling large data sets, handling spreadsheets and graphing, applying appropriate statistics, and writing accurate and concise scientific reports in journal article format.

Adam C. Hall (Smith College; )

2003-11-01

169

Sprite discharges on Venus and Jupiter-like planets: a laboratory investigation  

CERN Document Server

Large sprite discharges at high atmospheric altitudes have been found to be physically similar to small streamer discharges in air at sea level density. Based on this understanding, we investigate possible sprite discharges on Venus or Jupiter-like planets through laboratory experiments on streamers in appropriate CO2-N2 and H2-He mixtures. First, the scaling laws are experimentally confirmed by varying the density of the planetary gasses. Then streamer diameters, velocities and overall morphology are investigated for sprites on Venus and Jupiter; they are quite similar to those on earth, but light emissions in the visible range are fainter by two orders of magnitude. The discharge spectra are measured; they are dominated by the minority species N2 on Venus, while signatures of both species are found on Jupiter-like planets. The spectrum of a fully developed spark on Venus is measured. We show that this spectrum is significantly different from the expected sprite spectrum.

Dubrovin, Daria; van Veldhuizen, Eddie; Ebert, Ute; Yair, Yoav; Price, Colin; 10.1029/2009JA014851

2010-01-01

170

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

171

Mizunami Underground Research Laboratory project (rock mechanical investigations). MIZ-1 borehole investigations  

International Nuclear Information System (INIS)

In order to establish the scientific and technical basis of geological disposal of high level radioactive waste, Japan Atomic Energy Agency (JAEA) is advancing the geo-scientific research at the Mizunami Underground Laboratory (MIU). In this project, the surface-based investigation phase (Phase I) was finished in fiscal year 2004. Rock mechanics investigations were conducted in Phase I using the MIZ-1 borehole in order to understand the rock mechanical conditions deep underground and to construct a rock mechanical model of the MIU construction site. This report describes the results of these investigations. A brief summary is shown as follows. 1) Determining the average rock physical and mechanical properties using core from Toki Granite are: - apparent specific gravity: 2.62; - unconfined compressive strength (U.C.S.): 173Mpa; - tangent modulus at 50% U.C.S: 51.8Gpa; - poisson's ratio: 0.265. These results are consistent with the results of similar investigations in the nearby Shobasama site. 2) Estimation of in situ stress by stress measurements using cores. Four different methods (AE, DRA, ASR, and DSCA) were applied to estimate the in situ stress state. However the results are very low confidence due to very small deformation during drilling, excepting DSCA. 3) Determining of in situ stress by hydraulic fracturing. The horizontal, maximum principal stress is oriented to NW-SE (using north magnetic pole). Above six hundred meters depth, the in situ stress state is reverse fault type (SH > Sh ? Sv overburden pressure ?gh as Sv). But below it, the in situ stress state changed to a wrench or normal fault type (SV ? SH > Sh). 4) Rock mechanical model. In consideration of the investigations and geological model, we proposed a rock mechanical model consisting of two in situ stress states and homogeneous, rock mechanical properties. (author)

172

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

173

Students' Written Arguments in General Chemistry Laboratory Investigations  

Science.gov (United States)

This study aimed to examine the written arguments developed by college freshman students using the Science Writing Heuristic approach in inquiry-based general chemistry laboratory classrooms and its relationships with students' achievement in chemistry courses. Fourteen freshman students participated in the first year of the study while 19…

Choi, Aeran; Hand, Brian; Greenbowe, Thomas

2013-01-01

174

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

175

Experimental and Numerical Investigation of Reactive and Dissipative Mufflers  

Science.gov (United States)

In this research both experimental and numerical investigations are carried out for passive mufflers. These mufflers, both reactive and dissipative, can be used in automotive applications. The reactive mufflers have perforates, baffles, flow plugs and extended inlet/outlet tubes, whereas the dissipative mufflers have sound absorbing materials. A multi-domain boundary element method is used as a numerical technique for modeling such mufflers and predicting their transmission loss. In reactive mufflers, like the concentric resonators and plug flow mufflers, the transfer impedance across the perforate is incorporated in the multi-domain boundary element model. In dissipative mufflers, the sound absorbing material lining is treated both as bulk as well as locally reacting. To successfully incorporate perforates and sound absorbing materials in the boundary element models, experiments are conducted to determine the perforate transfer impedance and the propagation constant, characteristic impedance and surface impedance of the sound absorbing material. To validate the boundary element solution, an analytical one-dimensional solution for a duct with a perforated partition and the transmission loss of a family of reactive and dissipative mufflers are obtained. Various techniques to determine the transmission loss are investigated. One of the techniques, the transfer function method requires the design and fabrication of a perfect anechoic termination of the system, and it is a difficult task. Alternate methods are then investigated, where the transmission loss is computed from the experimentally determined four-pole parameters of the muffler in question. The two-load and the two-source location methods are used to determine the four-pole parameters and then the transmission loss, without the use of an anechoic termination. Excellent agreement is found between the results of the experimental investigation and the boundary element method for the various mufflers.

Mohanty, Amiya Ranjan

176

Experimental investigation of the MSFR molten salt reactor concept  

International Nuclear Information System (INIS)

In the paper experimental modelling and investigation of the MSFR concept will be presented. MSFR is a homogeneous, single region liquid fuelled fast reactor concept. In case of molten salt reactors the core neutron flux and fission distribution is determined by the flow field through distribution and transport of fissile material and delayed neutron precursors. Since the MSFR core is a single region homogeneous volume without internal structures, it is a difficult task to ensure stable flow field, which is strongly coupled to the volumetric heat generation. These considerations suggest that experimental modelling would greatly help to understand the flow phenomena in such geometry. A scaled and segmented experimental mock-up of MSFR was designed and built in order to carry out particle image velocimetry measurements. Basic flow behaviour inside the core region can be investigated and the measurement data can also provide resource for the validation of computational fluid dynamics models. Measurement results of steady state conditions will be presented and discussed.

177

Experimental investigation of the MSFR molten salt reactor concept  

Energy Technology Data Exchange (ETDEWEB)

In the paper experimental modelling and investigation of the MSFR concept will be presented. MSFR is a homogeneous, single region liquid fuelled fast reactor concept. In case of molten salt reactors the core neutron flux and fission distribution is determined by the flow field through distribution and transport of fissile material and delayed neutron precursors. Since the MSFR core is a single region homogeneous volume without internal structures, it is a difficult task to ensure stable flow field, which is strongly coupled to the volumetric heat generation. These considerations suggest that experimental modelling would greatly help to understand the flow phenomena in such geometry. A scaled and segmented experimental mock-up of MSFR was designed and built in order to carry out particle image velocimetry measurements. Basic flow behaviour inside the core region can be investigated and the measurement data can also provide resource for the validation of computational fluid dynamics models. Measurement results of steady state conditions will be presented and discussed.

Yamaji, Bogdan; Aszodi, Attila [Budapest University of Technology and Economics (Hungary). Inst. of Nuclear Techniques

2014-11-15

178

A Computational and Experimental Investigation of Shear Coaxial Jet Atomization  

Science.gov (United States)

The instability and subsequent atomization of a viscous liquid jet emanated into a high-pressure gaseous surrounding is studied both computationally and experimentally. Liquid water issued into nitrogen gas at elevated pressures is used to simulate the flow conditions in a coaxial shear injector element relevant to liquid propellant rocket engines. The theoretical analysis is based on a simplified mathematical formulation of the continuity and momentum equations in their conservative form. Numerical solutions of the governing equations subject to appropriate initial and boundary conditions are obtained via a robust finite difference scheme. The computations yield real-time evolution and subsequent breakup characteristics of the liquid jet. The experimental investigation utilizes a digital imaging technique to measure resultant drop sizes. Data were collected for liquid Reynolds number between 2,500 and 25,000, aerodynamic Weber number range of 50-500 and ambient gas pressures from 150 to 1200 psia. Comparison of the model predictions and experimental data for drop sizes at gas pressures of 150 and 300 psia reveal satisfactory agreement particularly for lower values of investigated Weber number. The present model is intended as a component of a practical tool to facilitate design and optimization of coaxial shear atomizers.

Ibrahim, Essam A.; Kenny, R. Jeremy; Walker, Nathan B.

2006-01-01

179

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)

180

Numerical and experimental investigations of laser forming processes  

Science.gov (United States)

Laser forming is a recently developed and highly flexible metal forming process. It uses laser-induced thermal distortion to shape a metal workpiece without hard tooling or external forces. A number of issues concerning laser forming are not yet fully understood. Understanding these aspects of laser forming is a challenging problem of considerable academic interest and practical applications. Efforts are made to advance knowledge in these areas. Numerical simulation models using finite element analysis are developed. The simulation results are compared to, and are consistent with, the experimental observations under a wide range of conditions. The laser forming process is investigated under the condition of constant line energy. Under this condition, the effects of velocity on temperature, net energy input, strain rate and internal flow stress are studied. Their collective effects on deformation and microstructure are presented. The influence of the strain rate in laser forming is investigated. To isolate and effectively study the strain rate effects, which are temperature dependent, a "constant peak temperature" method is developed with the aid of the numerical modeling and solution. Under the constant peak temperature condition, the effects of strain rate on forming efficiency, residual stress and hardness of the formed parts are studied. A new laser-scanning scheme is postulated to obtain convex forming insensitive to the initial state. This postulate is validated by experimental and numerical results. Effects of the scanning scheme parameters on the certainty of the convex forming, and dependence of the bending angle on the Fourier number, laser power, and velocity are further investigated. Mechanisms of the process of laser bending of tubes are examined to better understand the deformation characteristics such as wall thickness variation, cross-section ovalization, bending radius, and asymmetry. Factors important to these characteristics are experimentally and numerically investigated. Temporal and spatial distributions of temperature and stress/strain obtained from experimentally validated simulation models are also used to better understand additional phenomena accompanying the process, and to help devise ways to improve the process. The process effects on hardness and microstructure variations are also investigated.

Li, Wenchuan

2000-10-01

181

Laboratory and numerical investigations of air sparging using MTBE as a tracer  

DEFF Research Database (Denmark)

Air sparging experiments were conducted in a laboratory column to investigate air now and mass transfer behavior in different types of sand at different air injection rates. Methyl tertiary butyl ether (MTBE) was applied as a tracer, and by measuring the volatilization and the mean air content during the experiments, the air flow pattern and its influence on mass transfer were assessed. The experimental results showed large differences among the sand types. In fine sand, the mean air content was high and the volatilization of MTBE was rapid with total recovery after a few hours. In coarse sand, the mean air content was low and the volatilization of MTBE was limited. The results indicate two different air flow distributions. In fine-grained materials, a uniform air distribution can be expected compared to coarse-grained materials where isolated air channels will limit the mass transfer. Afterwards, the experiments were simulated using the numerical multiphase flow code T2VOC, and the results compared to those obtained in the laboratory. The experiments with fine sand were simulated well, while for coarser sand types the volatilization was highly overestimated. The differences between model and laboratory results were mainly attributed to the nonuniformity of the air saturation and the neglection of kinetics in the mass transfer formulation.

Mortensen, A. P.; Jensen, Karsten HØgh

2000-01-01

182

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

183

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

184

Experimental investigation of radiation transmission through a water spray  

International Nuclear Information System (INIS)

Radiation attenuation by a water spray is experimentally investigated. Spectral transmissivity measurements are performed between 1000 and 7000cm-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 6bar. 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 attenuation modification when increasing the water pressure is observed. A simulation is also performed to evaluate a numerical code developed in a companion study. The achieved agreement demonstrates the ability of the simulation to describe the radiation attenuation by the spray

185

Experimental investigation of a strongly shocked gas bubble.  

Science.gov (United States)

A free-falling, spherical, soap-film bubble filled with argon is subjected to a planar M=2.88 shock in atmospheric nitrogen; vorticity is deposited on the surface of the bubble during shock interaction, and the Richtmyer-Meshkov instability ensues. The geometrical development of the shocked bubble is diagnosed with laser sheet imaging and a planar slice showing two cross sections of both the major vortex ring and a secondary vortex ring is revealed experimentally for the first time. Quantitative measurements of the experimental data include the vortex velocity defect, and subsequent circulation calculations, along with a new set of relevant length scales. The shock wave strength, leading to a post-shock compressible regime, allows the study of the instability development in a regime between low Mach number shock tube experiments and high Mach number laser driven experiments that has not been investigated previously. PMID:15904378

Ranjan, Devesh; Anderson, Mark; Oakley, Jason; Bonazza, Riccardo

2005-05-13

186

Experimental Investigation for the Attenuation Coefficient of Ultrasonic Guided Wave  

International Nuclear Information System (INIS)

In general, ultrasonic guided wave techniques that used for an evaluation of the internal defect have been applied without considering energy loss. It can be found out that the significant attenuation is observed in the signal of structure with defect by the scattering and absorption. Even in the signal acquired from defect-free structure, this attenuation can be also significant. Therefore, it is very essential to determine the Lamb wave propagation characteristics depending on modes because the dispersibility of Lamb wave can be easily influenced by the attenuation effect with frequency and thickness. For this reason, changing the propagation distance, attenuation coefficient of each Lamb wave mode needs to be investigated by the contact pitch-catch method with PZT(piezoelectric) sensors. In this paper, the experimental attenuation coefficient is measured by choosing the following three different variables; mode, thickness and plate materials. As a result, experimental attenuation coefficient is obtained as the function of variables

187

Experimental Investigation for the Attenuation Coefficient of Ultrasonic Guided Wave  

Energy Technology Data Exchange (ETDEWEB)

In general, ultrasonic guided wave techniques that used for an evaluation of the internal defect have been applied without considering energy loss. It can be found out that the significant attenuation is observed in the signal of structure with defect by the scattering and absorption. Even in the signal acquired from defect-free structure, this attenuation can be also significant. Therefore, it is very essential to determine the Lamb wave propagation characteristics depending on modes because the dispersibility of Lamb wave can be easily influenced by the attenuation effect with frequency and thickness. For this reason, changing the propagation distance, attenuation coefficient of each Lamb wave mode needs to be investigated by the contact pitch-catch method with PZT(piezoelectric) sensors. In this paper, the experimental attenuation coefficient is measured by choosing the following three different variables; mode, thickness and plate materials. As a result, experimental attenuation coefficient is obtained as the function of variables

Lee, Dong Jin; Cho, Youn Ho; Lee, Joon Hyun; Shin, Dong Chul [Pusan National University, Busan (Korea, Republic of)

2009-10-15

188

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

189

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. a practical system.

190

Experimental study of hard-X ray emission from laboratory sparks  

Science.gov (United States)

We present the characterization of hard-X rays produced by meter-long laboratory sparks carried out at the high-voltage laboratory of RSE, Milano, Italy. Sparks are known to emit X-rays when positive and negative streamers connect, before breakdown. Numerical simulations suggest that X-rays are produced by Bremsstrahlung in air by electrons accelerated to the runaway regime in the high electric field at the streamers tip. Positive meter-long discharges are produced by a Marx generator loaded by a meter-long air gap formed by a spherical anode and a conical-shaped cathode. Maximum voltage at breakdown is about 1 MV. We investigate the production of X-rays by means of an array of scintillation detectors deployed around the cathode. Each detector is a 2'' NaI(Tl) scintillating crystal coupled to a photomultiplier tube (PMT). Each detector is battery-powered and enclosed in a metallic housing for EM shielding. Analog signal output is trasmitted to a shielded control room by means of optical fibre tranceivers, and then collected by a fast digitizer. We present the experimental setup and first results concerning detection efficiency, energy spectra, and geometrical distribution of the emission.

Marisaldi, Martino; Rizzi, Rolando; Levi, Giuseppe; Malgesini, Roberto; Villa, Andrea; Mazza, Paolo; Labanti, Claudio; Fuschino, Fabio; Campana, Riccardo; Bianchini, David; Brancaccio, Rossella; Montanari, Alessandro; Patrizii, Laura

2014-05-01

191

[Experimental vaginal dysbiosis on the model of white laboratory mice].  

Science.gov (United States)

Qualitative and quantitative composition of microbiocenosis of urogenital tract (UGT) of mice has been studied. When investigating UGT of mice in norm (n = 8), microorganisms of several genera with following occurrence frequency were detected: Lactobacillus (100%), Streptococcus (100%), Staphylococcus (87.5%), Micrococcus (12.5%), Bacillus (12.5%), Fusobacterium (87.5%), Peptococcus (62.5%), Peptostreptococcus (50%), Bacteroides (100%) and representatives of Enterobacteriaceae f (12.5%) family. A comparative analysis of UGT microflora in norm and under physiologically proceeding pregnancy helped to detect in the group of pregnant animals the increase of occurrence frequency of such conventionally-pathogenous organisms as representatives of Enterobacteriaceae family (6.86) and Peptococcus genus (1.37 times), representatives of Lactobacillus genus were found in 100% of animals. A possibility of UGT dysbiosis under microbialload made by the method of intravaginal introduction of 50 mkl of Staphilococcus aureus culture suspension which contains 1 x 109 cells/ml has been established. It was shown that clinical symptoms of dysbiosis (increase of pH, excretions at UGT outlet) correlate with disturbances in microbiocenosis of mice UGT which are characterized by a decrease of occurrence frequency and titer of saprophyte microorganisms, first of all, Lactobacillus (occurrence frequency decreased 15 times for anaerobic and 1.33 times for microaerophylic, and titers 1.32 times and 2.34 times, respectively), and by an increase of the titer of conventionally pathogenic bacteria, such as representatives of Enterobacteriaceae family (14.5 times) and Staphylococcus (6.17 times). Investigation of the effect of exogenic staphylococcal load on pregnancy has shown that the development of UGT dysbiosis affects the pregnancy result. Thus, it was established that there were three cases of abortion and two cases of natimortality which were registered in the group of female mice (n = 5) which were administered Staphylococcus after they became pregnant. The paper is presented in Russian. PMID:19351049

Voronkova, O S; Sirokvasha, E A; Vinnikov, A I

2008-01-01

192

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.)

193

A review of experimental investigations on thermal phenomena in nanofluids  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Nanoparticle suspensions (nanofluids have been recommended as a promising option for various engineering applications, due to the observed enhancement of thermophysical properties and improvement in the effectiveness of thermal phenomena. A number of investigations have been reported in the recent past, in order to quantify the thermo-fluidic behavior of nanofluids. This review is focused on examining and comparing the measurements of convective heat transfer and phase change in nanofluids, with an emphasis on the experimental techniques employed to measure the effective thermal conductivity, as well as to characterize the thermal performance of systems involving nanofluids.

Thomas Shijo

2011-01-01

194

Preliminary experimental investigation of boundary layer in decelerating flow  

Directory of Open Access Journals (Sweden)

Full Text Available Investigations of characteristics of turbulence inside boundary layer under decelerating flow were studied by means of constant temperature anemometer. The decelerating flow was simulated in the closed circuit wind tunnel 0.9 m × 0.5 m at IT AS CR. The free stream turbulence was either natural o risen up by square mesh plane grid. The details of experimental settings and measurement procedures of the instantaneous longitudinal velocity component are described and the distributions of intensity, skewness and kurtosis of turbulent fluctuations are discussed in the contribution.

P?íhoda J.

2013-04-01

195

Experimental and FE Investigation of Trimming of Aluminum Sheet Materials  

Science.gov (United States)

Aluminum alloy sheet materials AA6111-T4 and AA5754-O were evaluated with experimental and FE methods on the trimming behaviour. Influences of clearance and punch speed were investigated from different tool configurations, in which various combinations of parts were utilized. Load curves of punch force versus displacement and cut edge morphologies were compared at different categories. Optimal configurations of tooling, clearance and speed were analyzed. FE simulations of the trimming process with two-dimensional plane strain models using the element deletion technique were carried out. General agreements were obtained in studied trimming conditions for both materials.

Situ, Quan; Bruhis, Michael; Jain, Mukesh

2004-06-01

196

Experimental investigation on reconstruction guarantees in compressive Fresnel holography  

Science.gov (United States)

Compressive sensing has been successfully applied in digital holography (DH), which formulated holography as a compressive sensing problem, thus the reconstruction of hologram is inverted as the decompress and solving the minimization problem. The original information can be reconstructed accurately when the reconstruction conditions are guaranteed in different physical scheme and optical recording set-up. In this paper, the reconstruction conditions are investigated both theoretically and experimentally in near-field Fresnel propagation regime. The effect of recording distance on the physical properties of Fresnel wave propagation is demonstrated, and then show their effect on reconstructed image quality.

Wu, Fan; Wan, Yuhong; Man, Tianlong; Guo, Xiaole

2014-11-01

197

Experimental Investigation of Continuous-Wave Laser Ionization of Krypton  

Energy Technology Data Exchange (ETDEWEB)

This report describes experimental investigations of a method that uses continuous-wave (CW) lasers to ionize selected isotopes of krypton with high isotopic selectivity. The experiments show that the ionization rate is at least a factor of 100 lower than calculated with our model that has been described in a previous report. This discrepancy may be due to a much smaller excitation cross section that expected based on previous work and/or the aberrations in the ultraviolet beam used for the first step in the excitation. Additional problems with damage to mirrors, alignment instabilities, and manufacturers halting production of key products make this approach not worth further development at this time

Cannon, Bret D.; Shannon, Robert F.

2001-10-30

198

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.)

199

Experimental investigation of fast ion dynamics in TORPEX toroidal plasmas  

OpenAIRE

The goal of the present diploma work is to experimentally investigate the fast ion physics in TORPEX plasmas, in which interchange modes with flute characteristics and intermittent transport events, i.e. blobs, are observed to dominate the plasma dynamics. During the first part of the diploma, the Candidate will test different fast ion emitters on a test bench, which will be then mounted into the BN casing to form the fast ion source. In parallel, the Candidate will design an innovative in-ve...

Roulet, Boris

2010-01-01

200

Experimentally investigate ionospheric depletion chemicals in artificially created ionosphere  

International Nuclear Information System (INIS)

A new approach for investigating ionosphere chemical depletion in the laboratory is introduced. Air glow discharge plasma closely resembling the ionosphere in both composition and chemical reactions is used as the artificially created ionosphere. The ionospheric depletion experiment is accomplished by releasing chemicals such as SF6, CCl2F2, and CO2 into the model discharge. The evolution of the electron density is investigated by varying the plasma pressure and input power. It is found that the negative ion (SF6?, CCl2F2?) intermediary species provide larger reduction of the electron density than the positive ion (CO2+) intermediary species. The negative ion intermediary species are also more efficient in producing ionospheric holes because of their fast reaction rates. Airglow enhancement attributed to SF6 and CO2 releases agrees well with the published data. Compared to the traditional methods, the new scheme is simpler to use, both in the release of chemicals and in the electron density measurements. It is therefore more efficient for investigating the release of chemicals in the ionosphere.

201

Experimentally investigate ionospheric depletion chemicals in artificially created ionosphere  

Energy Technology Data Exchange (ETDEWEB)

A new approach for investigating ionosphere chemical depletion in the laboratory is introduced. Air glow discharge plasma closely resembling the ionosphere in both composition and chemical reactions is used as the artificially created ionosphere. The ionospheric depletion experiment is accomplished by releasing chemicals such as SF{sub 6}, CCl{sub 2}F{sub 2}, and CO{sub 2} into the model discharge. The evolution of the electron density is investigated by varying the plasma pressure and input power. It is found that the negative ion (SF{sub 6}{sup -}, CCl{sub 2}F{sub 2}{sup -}) intermediary species provide larger reduction of the electron density than the positive ion (CO{sub 2}{sup +}) intermediary species. The negative ion intermediary species are also more efficient in producing ionospheric holes because of their fast reaction rates. Airglow enhancement attributed to SF{sub 6} and CO{sub 2} releases agrees well with the published data. Compared to the traditional methods, the new scheme is simpler to use, both in the release of chemicals and in the electron density measurements. It is therefore more efficient for investigating the release of chemicals in the ionosphere.

Liu Yu; Cao Jinxiang; Wang Jian; Zheng Zhe; Xu Liang; Du Yinchang [CAS Key Laboratory of Basic Plasma Physics, Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2012-09-15

202

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.

203

Experimental investigation and performance test of heavy duty torque converter  

International Nuclear Information System (INIS)

The present study is an investigation on the characteristics of heavy load toque converter by experimental process. To get the dynamic performance, the dynamometer was used with a parameters of speed, torque, oil pressure and oil flux, etc. The torque converter was tested for various input speed, output oil pressure and input oil flow rate. All experiments were investigated in case that the speed ratio is increased. The torque ratio and capacity factor was in inverse proportion to speed. Engine revolution had a more effects at region of low speed ratio. But, the opposite phenomena were represented increase of efficiency. In result of this experiments, the characteristics of torque converter were not influenced by oil pressure and oil flux

204

Debye-Scherrer investigations of experimentally shocked silicates.  

Science.gov (United States)

Small ballistic ranges were used to perform controlled laboratory shock experiments on 12 selected silicates. Debye-Scherrer investigations of shocked materials revealed a gradual lattice breakdown of crystalline matter under shock. Individual mineral species behave selectively. Sheet silicates break down very easily, followed by tecto-silicates. Chain-, ino- and ortho-silicates are of considerably higher shock resistance. Depending on the mineral species, the first sign of shock damage is evidenced in the long range order at 20-70 kb. At intermediate pressures (100-200 kb) the long range order is essentially destroyed with the short range order heavily disturbed. At pressures exceeding 300 kb tecto-silicates are completely collapsed.

Hoerz, F.; Quaide, W. L.

1973-01-01

205

Experimental and Numerical Investigations in Single Point Incremental Sheet Forming  

Science.gov (United States)

As recent studies introduced Incremental Sheet Forming (ISF) process as a very promising technology to manufacture sheet metal parts by the CNC controlled movement of a simple generative tool, industrial interests on ISF have increased. Indeed, due to its various advantages, such process has been demonstrated as an alternative to reduce costs resulting from stamping technology when small batches or prototypes have to be manufactured. Nevertheless, the process still needs further developments. A process analysis based on experimental and numerical investigations is required to carefully analyze the capabilities of the process and to consolidate its application in sheet metal industries. Starting from experimental results on standard components to show the interest of ISF, an application is carried out accounting flexibility of the process linked to the fact that the punches or dies are avoided and preliminary results have been obtained through experimental tests to manufacture micro parts. At the same time, a FEM analysis has been carried out in order to get the characteristics of the formed parts. In order to study the control of the process, a first study is carried out to perform an on-line sheet thickness measurement.

Dejardin, S.; Thibaud, S.; Gelin, J. C.

2007-05-01

206

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

207

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.

208

Investigations of Solar Prominence Dynamics Using Laboratory Simulations  

Energy Technology Data Exchange (ETDEWEB)

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.

Paul M Bellan

2008-05-28

209

Experimental and three-dimensional finite element investigation of fatigue  

Science.gov (United States)

Materials often fail at cyclic loads that are lower than their ultimate strength or even their yield strength due to progressive internal material degradation; commonly known as fatigue. Moreover, there is a wide scatter in observed fatigue lives of mechanical components operating under identical loading conditions. The randomness of fatigue failure is considered to be linked to basic microstructural effects such as random microstructure topology and the initiation/growth of cracks along inter/transgranular planes. Several modeling approaches have been previously presented ranging from 2D discrete element to 3D Finite Element methods with explicit representation of microstructure topology and continuum damage mechanics to capture dispersion in rolling contact fatigue life and fatigue spalling. There is, however, a need to compare the modeling approach with experimental fatigue test conditions in order to verify and as required enhance the modeling approach to capture observed fatigue failure. This dissertation presents experimental test results and three-dimensional modeling approach that capture fatigue failure. The three-dimensional modeling approach is enhanced according to the experimental observations to consider inter/trans granular failure, different modes of fatigue initiation and propagation and finally for considering effect of plasticity in fatigue of rolling contacts. The following phenomena have been investigated: (1) Fatigue of microbeams: (a )Results of fatigue life and failure from 3D modeling of intergranular fatigue in microbeams are compared with experimental observations reported in literature (2) Tensile fatigue of thin sheets: (a) A test rig with a new grip and alignment system is developed to address the challenges associated with thin sheet testing and conduct fatigue experiments. (b) The 3D fatigue model is enhanced to capture the dominant transgranular fatigue observed in the experiments. The observed and modeled fatigue life and failure are compared. (3) Torsion fatigue of bearing steel variants: (a) Custom grips are developed and integrated with an MTS torsion test rig to undertake torsion testing of various bearing steel variants. (b) A model for torsional fatigue failure was developed and the experimental and numerical results are compared. (4) Rolling contact fatigue: (a) An improved 3D RCF model is developed which is computationally efficient and accurate compared to a previously published model. (b) The 3D fatigue model is enhanced to investigate the effects of plasticity and fatigue damage due to plastic strain accumulation on rolling contact fatigue.

Bomidi, John A. R.

210

The geoflow-experiment on ISS (part I): Experimental preparation and design of laboratory testing hardware  

Science.gov (United States)

Thermal convection in a spherical shell represents an important model in fluid dynamics and geophysics. Investigations on thermal convective instabilities occuring in the spherical gap flow under terrestrial conditions are of basic importance especially for the understanding of symmetry-breaking bifurcations during the transition to chaos. Microgravity,experiments on thermal convection with a simulated central force field are important for the understanding of large scale geophysical motions as the convective transport phenomena in the Earth's liquid outer core. This report summarizes the concurrent experimental (part I), numerical (part II) and theoretical (part III) studies for the preparation of an International Space Station (ISS) experiment inside the Fluid Science Laboratory (FSL). This special experimental device with respect to geophysical simulations is called GEOFLOW. A central symmetric force field similar to the gravity field acting on planets can be produced using the effect of the dielectrophoretic force field by applying a high voltage potential difference to the inner and outer sphere. Flow visualization, Wollaston Shearing Interferometry and Laser Doppler Velocimetry will be used to determine the expected flow pattern during the space experiments.

Egbers, Christoph; Beyer, Wolfgang; Bonhage, Astrid; Hollerbach, Rainer; Beltrame, Philippe

2003-07-01

211

Experimental investigation of a random repeated impact process  

Science.gov (United States)

A simple random repeated impact process which has previously been investigated theoretically has now been investigated experimentally. The process, which consists of a ball bouncing on a randomly vibrating surface, is analogous to loss of contact situations which can occur in machinery and transportation systems where a hard rolling element separates from the rolling surface. Experimental data was acquired and processed by using a digital data acquisition system and associated software. The results were obtained in the form of histograms which could be directly compared with the predicted probability density functions. The agreement between the predicted behaviour and the measured results was excellent, and confirmed the dependence of the behaviour of the random process on the coefficient of restitution and the excitation level. Also, it was verified that the probability density function of table velocities at impact was distinct from the Gaussian density function of the excitation. Consequently the theoretical analysis previously developed has been validated with sufficient confidence to enable it to be applied to predictions of acoustic noise generated by the impact process.

Wood, L. A.; Byrne, K. P.

1982-11-01

212

Controlling evaporative thermocapillary convection using external heating: An experimental investigation  

Energy Technology Data Exchange (ETDEWEB)

An experimental study has been undertaken to investigate evaporatively driven convection underneath a meniscus (liquid-vapour interface) formed in a vertically oriented capillary tube. The evaporation process is found responsible for inducing a convection pattern in the liquid phase below the meniscus. The convective structure was revealed using a {mu}-PIV technique. When external heating is applied to the system, the convection pattern is altered and can be reversed depending on the relative position of the heating element with respect to the liquid-vapour interface. An IR camera was used to measure temperature gradients generated by the heater along the capillary wall and along the liquid-vapour interface. This allowed the investigation of the relation between the temperature gradients generated along the tube wall and the convection taking place in the liquid under the effect of thermocapillary stress thus generated. The present study has demonstrated that the meniscus interfacial temperature profile is key for the onset of thermocapillary convection which is observed experimentally. (author)

Buffone, C.; Sefiane, K. [School of Engineering and Electronics, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JL, Scotland (United Kingdom)

2008-05-15

213

Experimental investigation of a dual purpose solar heating system  

International Nuclear Information System (INIS)

Highlights: • A dual purpose water and air heating system experimentally investigated. • This system can be used to heat water and air simultaneously. • Water can be used as a PCM material for heating air through the night. • Dual purpose systems achieve greater efficiency and lower heat dissipation. • Average efficiency of dual purpose system is 4% higher than single purpose system. - Abstract: In this study, a dual purpose water and air heating system is experimentally investigated. The system consists of a dual purpose flat solar collector and a vertical water storage tank. Water and air have natural and forced convection in the collector, respectively. The reason why dual purpose systems are used is to achieve greater efficiency and lower heat dissipation. Furthermore, high temperature and high performance can be obtained using this solar collector. These systems can be used to heat water and air simultaneously or separately. The hot water can be utilized for domestic applications or as a PCM material for heating air through the night. Besides, the hot air can be used in air conditioning systems, industrial processes and dryers. Therefore, using these collectors brings high energy savings. Absorber plate temperature variation, storage tank average temperature, system efficiency and air velocity effects are presented. Moreover, hourly efficiency is compared for single purpose and dual purpose systems. The results indicate that the efficiency of the dual purpose system is 3 to 5% higher than a single purpose system

214

Experimental Investigations of Hydrogen Purification by Purging through Metal Hydride  

Directory of Open Access Journals (Sweden)

Full Text Available 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 filled with LaFe0.1Mn0.3Ni4.8 intermetallic compound is tested at variable inlet hydrogen/inert gas composition with measuring mass flow, pressure, temperature and hydrogen content at the outlet both for charging and discharging mode. The estimations of hydrogen losses and purification capacity show certain advantages of the studied technology in comparison with PSA-like mode [1], especially from the point of view of operation regime simplification. The evident process slow-down observed in the experiment is connected with saturation of metal hydride porous bed by hydrogen and with temperature increase due to high thermal effect at sorption (~ 40 kJ/mole ?2. The ways for heat and mass transfer optimization together with the range of applicability of the method for fine hydrogen purification are described and discussed.

Blinov D.V.

2012-08-01

215

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

216

Experimental Investigation of Vent Evolution for High-speed Jets  

Science.gov (United States)

Volcanic eruptions typically involve the emission of high-pressure gas and solid mixtures from the earth. Many of these jets are overpressured, resulting in a complex series of flow compressions and expansions in the gas mixture. In addition, the solid structure erodes due to shear stresses and pressure differences in the flow, potentially changing the geometry of the vent nozzle. The evolving shape subsequently modifies the flow conditions. While this interrelated fluid and solid development has been demonstrated computationally, there currently is only limited experimental measurement of the transient response. Hence, a laboratory-scale apparatus has been assembled to produce overpressured flow of compressed air through erodible nozzles composed of metal and sand. Phase-locked particle image velocimetry (PIV) is used to examine the time-resolved fluid dynamics near the exit, while high-resolution imaging is applied to study the solid contour at specific instants. These data are compared with existing computational simulations to discuss the fluid and solid physics.

Solovitz, S.; Kim, D.; Ogden, D. E.

2012-12-01

217

Experimental investigation of the acceleration of deflagration in wake flow  

International Nuclear Information System (INIS)

In real gas cloud explosions turbulence is produced by the flow field caused by the combustion process. But also turbulence can 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 connected with high pressure levels. The reported laboratory-scale experiments are particularly designed in order to investigate the influence of a flow field present at the moment of ignition inside a partially confined hydrocarbon-air gas cloud. Experiments have been done using a flow channel capable to produce an unsteady flow field of combustible gas independent of the combustion process itself. The parameters which have been varied in these tests are the initial flow velocity, the gas-mixture composition and the geometry. The tests have been carried out mainly with stoichiometric ethylene-air and propane-air mixtures. The measured quantities are: pressure time history inside the test section, CH-radical radiation and also high speed photographs have been taken. The results show that the initial flow speed and the reactivity of the gas mixture investigated have a strong influence on the maximum overpressure and the duration of the positive pressure phase but also quenching effect may become important for high flow velocities and mixtures of low reactivity. (author)

218

Laboratory investigation of fire radiative energy and smoke aerosol emissions  

Science.gov (United States)

Fuel biomass samples from southern Africa and the United States were burned in a laboratory combustion chamber while measuring the biomass consumption rate, the fire radiative energy (FRE) release rate (Rfre), and the smoke concentrations of carbon monoxide (CO), carbon dioxide (CO2), and particulate matter (PM). The PM mass emission rate (RPM) was quantified from aerosol optical thickness (AOT) derived from smoke extinction measurements using a custom-made laser transmissometer. The RPM and Rfre time series for each fire were integrated to total PM mass and FRE, respectively, the ratio of which represents its FRE-based PM emission coefficient (CePM). A strong correlation (r2 = 0.82) was found between the total FRE and total PM mass, from which an average CePM value of 0.03 kg MJ-1 was calculated. This value agrees with those derived similarly from satellite-borne measurements of Rfre and AOT acquired over large-scale wildfires.

Ichoku, Charles; Martins, J. Vanderlei; Kaufman, Yoram J.; Wooster, Martin J.; Freeborn, Patrick H.; Hao, Wei Min; Baker, Stephen; Ryan, Cecily A.; Nordgren, Bryce L.

2008-07-01

219

Neglected impact of routine. Refinement of experimental procedures in laboratory mice  

OpenAIRE

The concept of refinement is one of the major issues in the field of laboratory animal science and aims at reducing the incidence and severity of painful, distressing or discomforting procedures applied to laboratory animals. In this thesis, it was argued that the term refinement should be extended beyond its original meaning: besides the aim to minimise pain and discomfort, refinement should also entail the effort of experimenters to obtain the best possible results from their animal experim...

Meijer, M. K.

2006-01-01

220

Current needs for the experimental investigations of the CHF phenomenon  

International Nuclear Information System (INIS)

Full text of publication follows: The physical modeling of the Critical Heat Flux phenomenon (CHF) relevant to LWR core conditions has been attempted with various degrees of success in the past. The modeling of dryout-type CHF (relevant to BWR) is considered more 'mature' since the two-phase flow pattern is known (annular flow) and the dryout event can be linked (at the macroscopic level) to the liquid film thinning and disappearance. The modeling of DNB-type CHF (relevant to PWR) has always been much more speculative since the most basic information, the two-phase flow pattern, is not well known under high heat flux (near-DNB) conditions. In addition, both CHF types are affected by near-wall small-scale effects. With the advance of numerical tools for two-phase flow simulation, the mechanistic modeling of CHF has recently evolved from 1-D to 3-D simulations where near-wall information, relevant to the CHF phenomena, are expected to be better captured, hence improving the accuracy of the simulations. However, this evolution does not resolve the modeling issues mentioned above and the need for experimental investigations should be a primary focus. In the view of the author, the main current needs for experimental investigations are listed below: In a first step, at the meso-scale, it is necessary to systematically identify (e.g. through direct visualizations) the two-phase flow pattern(s), and the corresponding high resolution wall thermal response, occurring near and wall thermal response, occurring near and during the DNB-type CHF phenomena under PWR conditions. Even though past investigations are numerous, they are often limited to low pressure and restricted to narrow range of conditions. In these experiments, use of the latest technological tools in high time resolution video imaging, void fraction measurement and wall temperature measurement will be beneficial. Investigation of a wide range of condition is necessary since the two-phase flow pattern may change, thereby potentially modifying the mechanism leading to DNB. In a second step, it is equally important to investigate small and micro-scale phenomena, such as the detailed behavior of a boiling wall or of a thin liquid film (in annular flow and underneath a vapor slug or a near-wall vapor clot) under high heat flux convective flow conditions in order to identify the physical events leading to the CHF and investigate innovative and practical solutions to provide margin to both dryout and DNB-type CHF (e.g. by modifying the fluid or wall properties). In addition to the need for experimental investigations, the numerical simulation of the phenomena needs to proceed carefully. Leaping ahead to 3-D numerical simulations without careful considerations of the physics of two-phase flow near CHF is quite hazardous. In some situations, 1-D tool and proper consideration of the phenomena (e.g. through the use of adequate constitutive relations) can be as accurate (and much more practical and computational efficient) as the use of 3-D tool due the high degree of uncertainty in the measurement and modeling of local parameters. (author)

221

Experimental, Theoretical, and Computational Investigation of Separated Nozzle Flows  

Science.gov (United States)

A detailed experimental, theoretical, and computational study of separated nozzle flows has been conducted. Experimental testing was performed at the NASA Langley 16-Foot Transonic Tunnel Complex. As part of a comprehensive static performance investigation, force, moment, and pressure measurements were made and schlieren flow visualization was obtained for a sub-scale, non-axisymmetric, two-dimensional, convergent- divergent nozzle. In addition, two-dimensional numerical simulations were run using the computational fluid dynamics code PAB3D with two-equation turbulence closure and algebraic Reynolds stress modeling. For reference, experimental and computational results were compared with theoretical predictions based on one-dimensional gas dynamics and an approximate integral momentum boundary layer method. Experimental results from this study indicate that off-design overexpanded nozzle flow was dominated by shock induced boundary layer separation, which was divided into two distinct flow regimes; three- dimensional separation with partial reattachment, and fully detached two-dimensional separation. The test nozzle was observed to go through a marked transition in passing from one regime to the other. In all cases, separation provided a significant increase in static thrust efficiency compared to the ideal prediction. Results indicate that with controlled separation, the entire overexpanded range of nozzle performance would be within 10% of the peak thrust efficiency. By offering savings in weight and complexity over a conventional mechanical exhaust system, this may allow a fixed geometry nozzle to cover an entire flight envelope. The computational simulation was in excellent agreement with experimental data over most of the test range, and did a good job of modeling internal flow and thrust performance. An exception occurred at low nozzle pressure ratios, where the two-dimensional computational model was inconsistent with the three-dimensional separation observed in the experiment. In general, the computation captured the physics of the shock boundary layer interaction and shock induced boundary layer separation in the nozzle, though there were some differences in shock structure compared to experiment. Though minor, these differences could be important for studies involving flow control or thrust vectoring of separated nozzles. Combined with other observations, this indicates that more detailed, three-dimensional computational modeling needs to be conducted to more realistically simulate shock-separated nozzle flows.

Hunter, Craig A.

2004-01-01

222

Quality assurance plan for the Close Support Laboratory for the remedial investigation at Oak Ridge National Laboratory, Oak Ridge, Tennessee  

International Nuclear Information System (INIS)

The primary purpose of the Close Support Laboratory (CSL) is to provide rapid radiological screening of investigation-derived samples before they are shipped to off-site laboratories for more detailed analyses. Analyses for volatile organic compounds and miscellaneous water quality parameters are also performed at the CSL. CSL data are also used to select samples for off-site laboratory analysis, for rapid qualitative and quantitative determinations, and for other processes when off-site analysis is not needed and/or is impractical. This plan specifies methods of implementing analytical and radiological protocols and procedures for the documentation, handling, control, and analysis of samples and describes the levels of authority and responsibility for laboratory operation. Specific quality control methods used by the CSL for individual analyses are described in project procedures

223

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

224

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

225

Experimental validation of thermal and pressure models in a laboratory simulator  

Energy Technology Data Exchange (ETDEWEB)

A simulator was developed for a laboratory and its operating HVAC system. The simulator consists of a room, re-heating coil, valve and damper, actuator, sensors, and controller. All of the components of the laboratory simulator, except for the room models, are taken from the literature. The room model includes algorithms to generate both steady and transient pressure and thermal responses under various operating conditions. The room pressure is tied to the lab safety constraints while the thermal response related to occupant comfort. In order to validate both room pressure and thermal models, a series of experimental results were used. The results were obtained from a series of tests conducted in a testing laboratory for building control products. Both pressure and thermal models are tested against measurements. The agreement between the simulated and actual response is good considering that the actual data were collected using commercial-grade sensors and a building automation system. This paper presents the details of the test laboratory, experimental setup, simulation process to validate the models, the test sequences, and the results comparing the actual and simulated data. The simulator is found to be a promising approach to designing and understanding the laboratory environment. The simulator provides insights into the dynamic interaction of the different control systems and the response of the laboratory environment. The simulator may serve as a model for developing the next generation of laboratory controllers.

Ahmed, O. [Landis and Staefa, Buffalo Grove, IL (United States); Mitchell, J.W.; Klein, S.A. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Mechanical Engineering

1998-12-31

226

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

227

Experimental investigations on vessel-hole ablation during severe accidents  

International Nuclear Information System (INIS)

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-B2O3 or the binary eutectic and non-eutectic salts NaNO3-KNO3, 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

228

Numerical and Experimental Investigations of Relaminarizing Plane Channel Flow  

Science.gov (United States)

Dominant disturbances in a relaminarizing plane channel flow were investigated numerically and experimentally. Flow visualization demonstrates that with decreasing the Reynolds number the fully developed turbulent flow becomes more intermittent and forms patches of small-scale turbulent structures. In place of the turbulence, longitudinally elongated streaks appear just above the minimal Reynolds number. A hot wire measurement indicates that the energy of the streamwise velocity fluctuation is maintained for the long streamwise distance for the condition in which the longitudinal streaks are dominate. The numerical simulation result reveals that the longitudinal streaks is characterized as large-scale vortical structure placed in the center region of the channel. It is concluded that the streak disturbance is one of sustainable nonlinear modes in a plane channel flow.

Seki, Daisuke; Numano, Takayuki; Matsubara, Masaharu

229

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 Re4. 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=105 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)

230

Experimental Investigation of Turbulence Specifications of Turbidity Currents  

Directory of Open Access Journals (Sweden)

Full Text Available 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 the distribution of turbulence energy, Reynolds stress and the turbulent intensity. It was concluded that the maximum turbulence intensity happens in both the interface and near the wall. Also, it was observed that the turbulence intensity reaches its minimum where maximum velocity occurs.

B Firoozabadi

2010-01-01

231

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

232

An experimental investigation of glare and restructured fiber metal laminates  

Science.gov (United States)

Fiber Metal Laminates (FMLs) are a group of materials fabricated by bonding glass/epoxy layers within metal layers. This class of materials can provide good mechanical properties, as well as weight savings. An FML known as Glass Laminate Aluminum Reinforced Epoxy (GLARE) was studied. An experimental investigation comprising of microscopy and tensile testing was carried out using different grades of GLARE. Microscopy revealed the construction details of GLARE, while tensile testing provided means of measuring and analyzing its stress-strain responses. Next, different metal surface pretreatment methods were explored. These included sandblasting, Phosphoric Acid Anodizing (PAA), and AC-130 Sol-Gel treatment. Woven S-2 glass, an epoxy adhesive, and aluminum alloy sheet metal were used to fabricate restructured FMLs using time and cost effective procedures. Additional microscopy and tensile testing allowed for comparisons with GLARE and aircraft grade aluminum alloys. The restructured FMLs showed similar behaviors to GLARE with potential significant improvements in fabrication efficiency.

Benedict, Adelina Vanessa

233

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

234

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

235

An experimental method to investigate impact on concrete slabs  

International Nuclear Information System (INIS)

A project is being carried out to investigate the response of bonded prestressed concrete slabs to hard impact. Test slabs are 1.5 m square and the impact is applied by means of a dropped mass. The contact force is measured during impact as well as displacements of the slab and strains in the steel and concrete. Experimental data is converted into digital form and stored in static memory before being processed on a micro-computer or displayed on an oscilloscope. The paper describes the arrangements of the test rig and instrumentation, discusses the reasons for selection of the techniques that have been used and comments on the interpretation of results. (orig.)

236

Experimental Investigation of the Induced Airflow of Corona Discharge  

Science.gov (United States)

In order to improve the acceleration effect of corona discharge acting on air, we present an experimental study on the induced airflow produced by corona discharge between two parallel electrodes. The parameters investigated are the type of electrodes, actuation voltage and the distance in the absence of free airflow. The induced flow velocity is measured directly in the accelerated region using the particle image velocimetry technology. The results show that if corona discharge is not developed into arc discharge, the induced airflow velocity increases nearly linearly with the applied voltage and the maximum induced airflow velocity near the needle electrode reaches 36 m/s. It is expected that in the future, the result can be referred to in the research about effect of active flow control to reach much higher induced airflow speed.

Huang, Yong; Zhang, Xin; Wang, Xun-Nian; Wang, Wan-Bo; Huang, Zong-Bo; Li, Hua-Xing

2013-09-01

237

Experimental investigation into scaling models of methane hydrate reservoir  

International Nuclear Information System (INIS)

Highlights: • The scaling criteria for methane hydrate reservoir are built. • The scaling criteria are verified by the experiments in two 3-D simulators. • The scaling criteria are used for predicting gas production of real hydrate reservoir. • Methane of 1.168 × 106 m3 is produced from the hydrate reservoir after 13.9 days. - Abstract: The Cubic Hydrate Simulator (CHS), a three-dimensional 5.8 L cubic pressure vessel, and the Pilot-Scale Hydrate Simulator (PHS), a three-dimensional 117.8 L pressure vessel, are used for investigating the production processes of hydrate. The gas production behaviors of methane hydrate in the porous media using the thermal stimulation method with a five-spot well system are studied. The experimental conditions are designed by a set of scaling criteria for the gas hydrate reservoir. The experimental results verify that the scaling criteria for gas hydrate production are reliable. The scaling criteria are used for predicting the production behavior of the real-scale hydrate reservoir. In the model of the real-scale hydrate reservoir with the size of 36 m × 36 m × 36 m, methane of 1.168 × 106 m3 (STP) is produced from the hydrate reservoir during 13.9 days of gas production. It is obtained that the gas recovery is 0.73, and the final energy efficiency is 9.5

238

Unsteady Ejector Performance: an Experimental Investigation Using a Pulsejet Driver  

Science.gov (United States)

An experimental investigation is described in which thrust augmentation and mass entrainment were measured for a variety of simple cylindrical ejectors driven by a gasoline-fueled pulsejet. The ejectors were of varying length, diameter, and inlet radius. Measurements were also taken to determine the effect on performance of the distance between pulsejet exit and ejector inlet. Limited tests were also conducted to determine the effect of driver cross-sectional shape. Optimal values were found for all three ejector parameters with respect to thrust augmentation. This was not the case with mass entrainment, which increased monotonically with ejector diameter. Thus, it was found that thrust augmentation is not necessarily directly related to mass entrainment, as is often supposed for ejectors. Peak thrust augmentation values of 1.8 were obtained. Peak mass entrainment values of 30 times the driver mass flow were also observed. Details of the experimental setup and results are presented. Preliminary analysis of the results indicates that the enhanced performance obtained with an unsteady jet (primary source) over comparably sized ejectors driven with steady jets is due primarily to the structure of the starting vortex-type flow associated with the former.

Paxson, Daniel E.; Wilson, Jack; Dougherty, Kevin T.

2002-01-01

239

Experimental investigation of the piano hammer-string interaction.  

Science.gov (United States)

Experimental techniques for investigating the piano hammer-string interaction are described. It is argued that the accuracy, consistency, and scope of conclusions of previous studies can be compromised by limitations of the conventional methods relating to key inputs; physical distortion; numerical distortion, particularly when differentiation or integration of measured signals is used to derive primary response variables; contact identification; and synchronization issues. These problems are discussed, and experimental methods that have been devised to avoid them are described and illustrated by detailed results from a study of the hammer-string interaction in a vertical piano. High resolution displacements are obtained directly by non-contact high-speed imaging and quantitative motion tracking. The attention focused on achieving very accurate and consistent temporal and spatial alignment, including the objective procedure used for contact identification, allows meaningful comparisons of responses from separate tests. String motion at the strike point and on each side of it, as well as hammer motion, is obtained for eight dynamic levels from 1.06 to 2.98 m/s impact velocity. Detailed observations of the force-compression behavior of the hammer interacting with real strings are presented. The direct effects of hammer shank deflection and agraffe string pulses on the interaction are also highlighted. PMID:23556611

Birkett, Stephen

2013-04-01

240

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.)

241

Experimental Investigation of Vortex Ring Evolution at Low Reynolds Number  

Science.gov (United States)

Evolution of low Reynolds number vortex rings in an infinite fluid has been well studied numerically and analytically, but the vortex formation process is typically ignored in these studies. In the present investigation, vortex rings were studied experimentally to determine the effects of formation conditions on vortex ring evolution as Reynolds number is decreased. Vortex rings were generated using a mechanical piston-cylinder vortex ring generator for jet Reynolds numbers in the range 10 to 1000 and piston stroke to jet diameter ratios between 0.5 to 2.0. The vortex rings were imaged using planar laser induced fluorescence and using dye visualization, both recorded with a digital camera. The images were used to obtain the vortex ring velocity and net displacement. The results show increased ring velocity and displacement with higher stroke ratios. Additionally, lower Reynolds numbers resulted in quicker deceleration and decreased maximum displacement. The experimental results will be compared with analytical models of viscous vortex rings traveling in an infinite fluid.

Couch, Lauren; Krueger, Paul

2008-11-01

242

Experimental Investigation of Vortex Ring Interaction with Inclined Surfaces  

Science.gov (United States)

A number of experimental and numerical studies have described the collision of a laminar vortex ring with an inclined surface and noted similarities with hairpin vortices found in turbulent boundary layers. However, the dependence of the observed flow on the vortex ring properties and angles of collision have largely been neglected. In the present investigation, vortex ring interactions with an inclined plate were studied experimentally to determine the effects of plate angle on the flow evolution and draw comparisons with coherent structures in turbulent boundary layers. Vortex rings were generated using a mechanical piston-cylinder vortex ring generator at jet Reynolds numbers ranging from 1000 to 3000 and stroke length-to-piston diameter ratios from 0.5 to 2. The plate angle relative to the initial axis of the vortex ring ranged from 3 to 70 degrees. Flow observations were made using planar laser induced fluorescence, 2D digital particle image velocimetry (DPIV), and 3D defocusing DPIV (DDPIV). Results show deformation and stretching of the vortex ring into a loop-like vortex and the generation of secondary vorticity at the surface of the plate.

Couch, Lauren D.; Krueger, Paul S.

2009-11-01

243

Experimental investigation of mixing-enhanced swirl flows  

International Nuclear Information System (INIS)

The experimental objective was to compare disintegration characteristics from the internal mixing pneumatic nozzles under the different operating conditions in terms of swirl angles. For this investigation, supplied air pressures and nozzle configuration ratios were fixed. This experimental comparison is of fundamental importance to the understanding and modeling of turbulent atomization because the axisymmetric swirling flows involve relatively complex interactions. For the measurement, four internal swirl mixing nozzles with axisymmetric holes at swirl angles of 15 .deg., 30 .deg., 45 .deg., and 60 .deg. to the central axis were employed, which is responsible for the enhancement of mixing in pneumatic jets. To illustrate the swirl phenomena quantitatively, the distributions of mean velocities, turbulence intensities, and SMD (Sauter mean diameter, or D32) variations with different configuration ratio were comparatively analyzed. It indicated that the atomization characteristics are performed well in the case of 30 .deg. of swirl angle, and that turbulence intensities are gradually degenerated with the increase of radial distances, showing a slight increment of SMD at downstream region. In particular, measurements showed that nozzle configuration is one of the significant geometrical parameters affecting the spray trajectories

244

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

245

Experimental and theoretical investigation of column - flat slab joint ductility  

International Nuclear Information System (INIS)

Most modern seismic codes use ductility as one of the basic design parameters. Actually, ductility defines the ability of a structure or its elements to absorb energy by plastic deformations. Until the end of the previous century ductility was defined qualitatively. Most research works related to ductility are focused on structural elements' sections. This study was aimed at complex experimental and theoretical investigation of flat slab-column joints ductility. It is one of the first attempts to obtain quantitative values of joint's ductility for the case of high strength concrete columns and normal strength concrete slabs. It was shown that the flat slab-column joint is a three-dimension (3D) element and its ductility in horizontal and vertical directions are different. This is the main difference between ductility of elements and joint ductility. In case of flat slab-column joints, essential contribution to joint's ductility can be obtained due to the slab's confining effect. Based on experimental data, the authors demonstrate that flat slab-column joint's ductility depends on the joint's confining effect in two horizontal and vertical directions. Furthermore, the influence of slab load intensity and slab reinforcement ratio on the joint's ductility is performed in this study. It is also demonstrated that the effect of the ratio between the slab thickness and the column's section dimension on the ductility parameter is significant. Equations for obtaining a quantitative value of a flat slab-column joint's ductility parameter were developed.

246

Experimental investigation of transient boiling heat transfer in microchannels  

International Nuclear Information System (INIS)

This paper presents an experimental investigation of flow boiling heat transfer in a single 0.3 x 12.7 mm2 rectangular microchannel. Water and ethanol are employed as test fluids. The test section, which is made of the nickel alloy Inconel 600, is electrically heated. The examined parameter ranges are: mass fluxes between 50 and 500 kg/m2s and heat fluxes up to 400 kW/m2 at an outlet pressure of 0.1 MPa. Infrared thermography is employed to register the outer wall temperatures of the channel. This measurement method is especially appropriate for the analysis of the transient behavior of boiling in microchannels, which has been often reported in the literature. Infrared images of the test section are recorded at a frequency of 150 Hz using the half image mode. Data are collected over 25 s and the behavior of the obtained wall temperatures is analyzed. Local heat transfer coefficients are then calculated from the time averaged outer wall temperatures. Finally, the experimental values are compared with widely used correlations

247

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.

248

Laboratory investigations of iceberg capsize dynamics, energy dissipation and tsunamigenesis  

Science.gov (United States)

We present laboratory experiments designed to quantify the stability and energy budget of buoyancy-driven iceberg capsize. Box-shaped icebergs were constructed out of low-density plastic, hydrostatically placed in an acrylic water tank containing freshwater of uniform density, and allowed (or forced, if necessary) to capsize. The maximum kinetic energy (translational plus rotational) of the icebergs was ˜15% of the total energy released during capsize, and radiated surface wave energy was ˜1% of the total energy released. The remaining energy was directly transferred into the water via hydrodynamic coupling, viscous drag, and turbulence. The dependence of iceberg capsize instability on iceberg aspect ratio implied by the tank experiments was found to closely agree with analytical predictions based on a simple, hydrostatic treatment of iceberg capsize. This analytical treatment, along with the high Reynolds numbers for the experiments (and considerably higher values for capsizing icebergs in nature), indicates that turbulence is an important mechanism of energy dissipation during iceberg capsize and can contribute a potentially important source of mixing in the stratified ocean proximal to marine ice margins.

Burton, J. C.; Amundson, J. M.; Abbot, D. S.; Boghosian, A.; Cathles, L. M.; Correa-Legisos, S.; Darnell, K. N.; Guttenberg, N.; Holland, D. M.; MacAyeal, D. R.

2012-01-01

249

Laboratory investigations: Low Earth orbit environment chemistry with spacecraft surfaces  

Science.gov (United States)

Long-term space operations that require exposure of material to the low earth orbit (LEO) environment must take into account the effects of this highly oxidative atmosphere on material properties and the possible contamination of the spacecraft surroundings. Ground-based laboratory experiments at Los Alamos using a newly developed hyperthermal atomic oxygen (AO) source have shown that not only are hydrocarbon based materials effected but that inorganic materials such as MoS2 are also oxidized and that thin protective coatings such as Al2O3 can be breached, producing oxidation of the underlying substrate material. Gas-phase reaction products, such as SO2 from oxidation of MoS2 and CO and CO2 from hydrocarbon materials, have been detected and have consequences in terms of spacecraft contamination. Energy loss through gas-surface collisions causing spacecraft drag has been measured for a few select surfaces and has been found to be highly dependent on the surface reactivity.

Cross, Jon B.

1990-01-01

250

Experimental and theoretical investigation of anaerobic fluidized bed biofilm reactors  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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 syste [...] m 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-active biomass is considered to be particulate material subject to hydrolysis. The model includes the anaerobic conversion for complex substrate degradation and kinetic parameters selected from the literature. The experimental set-up consisted of two mesophilic (36±1ºC) lab-scale AFBRs (R1 and R2) loaded with sand as inert support for biofilm development. The reactor start-up policy was based on gradual increments in the organic loading rate (OLR), over a four month period. Step-type disturbances were applied on the inlet (glucose and acetic acid) substrate concentration (chemical oxygen demand (COD) from 0.85 to 2.66 g L-1) and on the feed flow rate (from 3.2 up to 6.0 L d-1) considering the maximum efficiency as the reactor loading rate switching. The predicted and measured responses of the total and soluble COD, volatile fatty acid (VFA) concentrations, biogas production rate and pH were investigated. Regarding hydrodynamic and fluidization aspects, variations of the bed expansion due to disturbances in the inlet flow rate and the biofilm growth were measured. As rate coefficients for the biofilm detachment model, empirical values of 3.73?10(4) and 0.75?10(4) s² kg-1 m-1 for R1 and R2, respectively, were estimated.

M., Fuentes; M. C., Mussati; P. A., Aguirre; N. J., Scenna.

2009-09-01

251

Experimental and theoretical investigation of anaerobic fluidized bed biofilm reactors  

Directory of Open Access Journals (Sweden)

Full Text Available 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-active biomass is considered to be particulate material subject to hydrolysis. The model includes the anaerobic conversion for complex substrate degradation and kinetic parameters selected from the literature. The experimental set-up consisted of two mesophilic (36±1ºC lab-scale AFBRs (R1 and R2 loaded with sand as inert support for biofilm development. The reactor start-up policy was based on gradual increments in the organic loading rate (OLR, over a four month period. Step-type disturbances were applied on the inlet (glucose and acetic acid substrate concentration (chemical oxygen demand (COD from 0.85 to 2.66 g L-1 and on the feed flow rate (from 3.2 up to 6.0 L d-1 considering the maximum efficiency as the reactor loading rate switching. The predicted and measured responses of the total and soluble COD, volatile fatty acid (VFA concentrations, biogas production rate and pH were investigated. Regarding hydrodynamic and fluidization aspects, variations of the bed expansion due to disturbances in the inlet flow rate and the biofilm growth were measured. As rate coefficients for the biofilm detachment model, empirical values of 3.73?10(4 and 0.75?10(4 s² kg-1 m-1 for R1 and R2, respectively, were estimated.

M. Fuentes

2009-09-01

252

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

253

A novel laboratory set-up for investigating surface and interface reactions during short term annealing cycles at high temperatures.  

Science.gov (United States)

High temperature oxidation is an important research discipline that covers many topics in steel manufacture and modern energy research. To account for the need of adjusting accurate processing conditions, recent developments of the high temperature laboratory setup at the Max-Planck-Institut fu?r Eisenforschung GmbH will be presented. The experimental assembly has been optimized to investigate surface and interface reactions at elevated temperatures in low oxygen activity gases, covering a large field of experimental possibilities. Many efforts have been taken to enable an accurate control and in situ monitoring of process conditions such as gas flow, gas composition, impurity content, and mass change of the sample. PMID:24007108

Auinger, M; Vogel, D; Vogel, A; Spiegel, M; Rohwerder, M

2013-08-01

254

A novel laboratory set-up for investigating surface and interface reactions during short term annealing cycles at high temperatures  

Science.gov (United States)

High temperature oxidation is an important research discipline that covers many topics in steel manufacture and modern energy research. To account for the need of adjusting accurate processing conditions, recent developments of the high temperature laboratory setup at the Max-Planck-Institut für Eisenforschung GmbH will be presented. The experimental assembly has been optimized to investigate surface and interface reactions at elevated temperatures in low oxygen activity gases, covering a large field of experimental possibilities. Many efforts have been taken to enable an accurate control and in situ monitoring of process conditions such as gas flow, gas composition, impurity content, and mass change of the sample.

Auinger, M.; Vogel, D.; Vogel, A.; Spiegel, M.; Rohwerder, M.

2013-08-01

255

Inhibition of carcinogenesis by polyphenols: evidence from laboratory investigations.  

Science.gov (United States)

Many plant polyphenolic compounds have been shown to have cancer-preventing activities in laboratory studies. For example, tea and tea preparations have been shown to inhibit tumorigenesis in a variety of animal models of carcinogenesis, involving organ sites such as the skin, lungs, oral cavity, esophagus, stomach, liver, pancreas, small intestine, colon, and prostate. In some of these models, inhibitory activity was demonstrated when tea was administered during the initiation, promotion, or progression stage of carcinogenesis. The cancer-preventing activities of these and other polyphenols, such as curcumin, genistein, and quercetin, are reviewed. In studies in vitro, many of these compounds have been shown to affect signal transduction pathways, leading to inhibition of cell growth and transformation, enhanced apoptosis, reduced invasive behavior, and slowed angiogenesis. However, the concentrations used in cell culture studies were much higher than those found in vivo. If we propose mechanisms for cancer prevention on the basis of cell line experiments, then these activities must be demonstrated in vivo. The bioavailability, ie, tissue and cellular concentrations, of dietary polyphenols is a determining factor in their cancer-preventing activity in vivo. For example, compounds such as curcumin are effective when applied topically to the skin or administered orally to affect the colon but are not effective in internal organs such as the lungs. More in-depth studies on bioavailability should facilitate correlation of mechanisms determined in vitro with in vivo situations, increase our understanding of dose-response relationships, and facilitate extrapolation of results from animal studies to human situations. PMID:15640492

Lambert, Joshua D; Hong, Jungil; Yang, Guang-Yu; Liao, Jie; Yang, Chung S

2005-01-01

256

"They Sweat for Science": The Harvard Fatigue Laboratory and Self-Experimentation in American Exercise Physiology.  

Science.gov (United States)

In many scientific fields, the practice of self-experimentation waned over the course of the twentieth century. For exercise physiologists working today, however, the practice of self-experimentation is alive and well. This paper considers the role of the Harvard Fatigue Laboratory and its scientific director, D. Bruce Dill, in legitimizing the practice of self-experimentation in exercise physiology. Descriptions of self-experimentation are drawn from papers published by members of the Harvard Fatigue Lab. Attention is paid to the ethical and practical justifications for self-experimentation in both the lab and the field. Born out of the practical, immediate demands of fatigue protocols, self-experimentation performed the long-term, epistemological function of uniting physiological data across time and space, enabling researchers to contribute to a general human biology program. PMID:25139499

Johnson, Andi

2014-08-20

257

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

258

An experimental investigation of loop seal clearings in SBLOCA tests  

International Nuclear Information System (INIS)

Highlights: • An experimental study of the loop seal clearing in the SBLOCAs was performed. • Loop seal behaviors with related parameters were investigated. • The mechanism of initiation of a loop seal clearing was suggested. • The sustaining of a loop seal clearing without refilling was evaluated. - Abstract: An investigation of the loop seal clearing (LSC) in a small-break loss-of-coolant accident (SBLOCA) for direct vessel injection (DVI) line and cold leg (CL) breaks was performed. The behavior of an LSC appears to be closely related to the break location and break size. In the tests of SBLOCAs, a loop seal or cross-over leg (COL) in the broken loop was cleared first, and the number of loop seals cleared was dependent on the break size. The larger the break size was, the more the loop seals or COLs that were cleared. The location of the LSCs appeared to have a consistent behavior under each scenario. In the SBLOCA tests, the downcomer water level just before an LSC was a very important parameter to the peak cladding temperature (PCT). The initiation of an LSC might not be related to the existing flooding condition, but to the magnitude of the pressure difference between the reactor upper head and downcomer, which is sufficient to push the upflow leg of a COL. The sustaining of an LSC without refilling was evaluated using the test data and existing flooding conditions

259

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

260

Experimental investigation of water sprayed finned heat exchanger tube bundles  

International Nuclear Information System (INIS)

Experimental investigations have been made to study the performance of two finned tube-bundle heat exchangers (FORGO type) when wetted by water sprays. The heat exchangers are designed to cool water in a dry cooling tower. The test-elements had a frontal area of 1 m2. The water sprays were created by 20 nozzles, 200 mm in front of the heat exchangers. Air velocities at the inlet of the coolers were in the range 0,8 m/s to 12 m/s and initial temperature differences ITD reached 45 degrees C. The test facility was designed to determine the combined latent and sensible heat fluxes in the wetted heat exchanger, the airside pressure drop and the air humidity and temperature at the exchanger inlet and outlet, and to measure the weight of the water wetting the cooler's surface. The sprayed test elements were investigated in different positions, but most of the experiments were carried out in the position with the fins horizontal

261

Ozone decomposition on Saharan dust: an experimental investigation  

Directory of Open Access Journals (Sweden)

Full Text Available The heterogeneous reaction between O3 and authentic Saharan dust surfaces was investigated in a Knudsen reactor at approx 296 K. O3 was destroyed on the dust surface and O2 was formed with conversion efficiencies of 1.0 and 1.3 molecules O2 per O3 molecule destroyed for unheated and heated samples, respectively. No O3 desorbed from exposed dust samples, showing that the uptake was irreversible. The uptake coefficients for the irreversible destruction of O3 on (unheated Saharan dust surfaces depended on the O3 concentration and varied between 3.5 x 10-4 and 5.5 x 10-6 for the initial uptake coefficient (g0 approx 3 x 10-5 at 30 ppbv O3 STP and between 4.8 x 10-5 and 2.2 x 10-6 for the steady-state uptake coefficient (gss approx 7 x10-6 at 30 ppbv O3 STP. At very high O3 concentrations the surface was deactivated, and O3 uptake ceased after a certain exposure period. Sample re-activation (i.e. de-passivation was found to occur over periods of hours, after exposure to O3 had ceased, suggesting that re-activation processes play a role both in the laboratory and in the atmosphere.

F. Hanisch

2003-01-01

262

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

263

Theoretical and Experimental Investigation of Liquid Metal MHD Power Generation  

International Nuclear Information System (INIS)

Liquid metal magnetohydrodynamic power generation for space is studied. Closed- loop circulation of liquid metal without moving mechanical parts, and generation of electric power from the circulating metal, have been investigated analytically and experimentally, and the attainable cycle efficiencies have been calculated. Recent literature has pointed out the possibility of efficient a.c. generators with liquid metal as the working fluid, and this type of generator is under study. Analysis indicates that efficiencies up to 65% are attainable in a travelling-wave induction generator at the available liquid metal velocities of 100-200 m/sec, provided the generator has a length/gap ratio of no more than 50 for low friction loss, has an electrical length of no more than three wavelengths for low winding loss, and has end-effect compensation for cancelling finite-length effects in the power-generating region. The analysis leading to these conclusions is presented. The type of end-effect correction being studied is the ''compensating-pole'' technique in which an oscillating magnetic field is applied to the fluid entering and leaving the generator to make the flux linkages within the generator the same as those in a rotating or ''infinite'' generator. An experimental one-wavelength generator employing compensating poles has been fabricated, and empty-channel magnetic field measurements have been completed in preparation for tests with NaK. Two types of field measurements were NaK. Two types of field measurements were made: d.c. measurements to determine the field profile as a function of phase angle and a.c. measurements to investigate the synchronization of the compensating poles with the travelling wave. The d.c. results showed that the flux linkages in the power generating region can be held close to those in a rotating machine, and the a.c. results showed that the compensating poles can be accurately synchronized with the travelling wave through transformer coupling. The component efficiencies from the analyses and experiments were combined to predict the cycle efficiencies possible in space applications. The calculations included the different liquid MHD cycles and working fluids that have been proposed in the literature, and these cycles are reviewed and compared. A possible limitation on lifetime at the 1100-1500°K temperatures needed for a space power plant is erosion by the high velocity liquid metal, and this problem is being investigated in a 70 m/sec lithium loop. (author)

264

Laboratory Investigation of Entrainment and Mixing in Oceanic Overflows  

CERN Document Server

We present experimental measurements of a wall-bounded gravity current, motivated by characterizing natural gravity currents such as oceanic overflows. We use particle image velocimetry and planar laser-induced fluorescence to simultaneously measure the velocity and density fields as they evolve downstream of the initial injection from a turbulent channel flow onto a plane inclined at 10$^\\circ$ with respect to horizontal. The turbulence level of the input flow is controlled by injecting velocity fluctuations upstream of the output nozzle. The initial Reynolds number based on Taylor microscale of the flow, R$_\\lambda$, is varied between 40 and 120, and the effects of the initial turbulence level are assessed. The bulk Richardson number $Ri$ for the flow is about 0.3 whereas the gradient Richardson number $Ri_g$ varies between 0.04 and 0.25, indicating that shear dominates the stabilizing effect of stratification. Kelvin-Helmholtz instability results in vigorous vertical transport of mass and momentum. We pres...

Philippe, Odier; Ecke, Robert E

2013-01-01

265

Site characterization investigations at Oak Ridge National Laboratory  

International Nuclear Information System (INIS)

The geologic and geohydrologic characterization and assessment techniques currently used at ORNL are integrated into a systematic approach. The investigations are multi-faceted, and involve investigators with a variety of expertise. Characterization studies are designed to obtain the data requirements of pathways analysis and facility design in addition to the detailed site description. The approach effectively minimizes the redundancy and lack of coordination which often arise when the study is broken down into totally independent tasks. The geologic environment of the Oak Ridge Reservation is one of structural and stratigraphic complexity which requires a comprehensive and systematic approach to characterize. Recent characterization studies have included state-of-the-science techniques in the areas of unsaturated zone testing, geochemical tests to determine attenuation properties of soils, and numerical analyses of site performance. The results of these studies and analyses are changing the technology of shallow land burial by indicating that chemically stable waste forms are required to limit radionuclide migration to acceptable levels. 11 refs., 1 tab

266

The three-spined stickleback-Schistocephalus solidus system: an experimental model for investigating host-parasite interactions in fish.  

Science.gov (United States)

Plerocercoids of the pseudophyllidean cestode Schistocephalus solidus infect the three-spined stickleback Gasterosteus aculeatus, with important consequences for the biology of host fish. Techniques for culturing the parasite in vitro and generating infective stages that can be used to infect sticklebacks experimentally have been developed, and the system is increasingly used as a laboratory model for investigating aspects of host-parasite interactions. Recent experimental laboratory studies have focused on the immune responses of hosts to infection, the consequences of infection for the growth and reproductive development of host fish and the effects of infection on host behaviour. Here we introduce the host and the parasite, review the major findings of these recent experimental infection studies and identify further aspects of host parasite interactions that might be investigated using the system. PMID:19835650

Barber, I; Scharsack, J P

2010-03-01

267

An experimental investigation of wave propagation in fractured brittle material  

Science.gov (United States)

An experimental method for visualizing and analyzing the propagation of plate stress waves in a brittle plate is developed. A procedure has been developed to cast Break-Away glass (a low molecular weight polystyrene material) plate specimens in an open mold. The specimens are loaded with short duration (200 [...]s) stress pulses on one edge by an electromagnetic stress wave generator. The propagating stress waves generate out-of-plane deformations on the specimen surface, which are observed using Twyman-Green interferometry. The fringe patterns created by the propagating stress waves are captured using a high speed camera - pulsing laser combination at 4[...]s intervals.A generalized "Fringe Analysis Procedure" is developed to subtract the reference interferogram from the subsequent interferograms. The "Fringe Analysis Procedure" employs a fringe edge detection algorithm to obtain the sharp edge lines of the fringes in an interferogram. A digitizer is used to extract points on these edge lines and assign them fringe numbers. The "griddata" option in the commercial software "Matlab" is utilized to interpolate the deformation field on to the nodes of a uniform grid. The field values at these nodes in the reference image are then subtracted from corresponding values in the subsequent images to obtain the actual deformation patterns generated by the propagating stress waves. The "Fringe Analysis Procedure" has eliminated the subjective element introduced by human judgment in manual fringe tracing procedures.The developed experimental method and the image analysis technique is used to investigate the propagation of stress waves in Break-Away glass plate specimens.

Patel, Bibhuti Bhusan

268

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)

269

Experimental and numerical investigation of Acoustic streaming (Eckart streaming)  

Science.gov (United States)

The application of sound waves in the bulk of a fluid can generate steady or quasi-steady flows reffered to as Acoustic streaming flows. We can distinguish two kind of acoustic streaming: The Rayleigh Streaming is generated when a standing acoustic waves interfere with solid walls to give birth to an acoustic boundary layer. Steady recirculations are then driven out of the boundary layer and can be used in micro-gravity, where the free convection is too weak or absent, to enhance the convective heat or mass transfer and cooling the electronic devises [1]. The second kind is the Eckart streaming, which is a flow generated far from the solid boundaries, it can be used to mix a chemical solutions [2], and to drive a viscous liquids in channels [3-4], in micro-gravity area. Our study focuses on the Eckart streaming configuration, which is investigated both numerical and experimental means. The experimental configuration is restricted to the case of a cylindrical non-heated cavity full of water or of a water+glycerol mixture. At the middle of one side of the cavity, a plane ultrasonic transducer generates a 2MHz wave; an absorber is set at the opposite side of the cavity to avoid any reflections. The velocity field is measured with a standard PIV system. [1] P. Vainshtein, M. Fichman and C. Gutfinger, "Acoustic enhancement of heat transfer between two parallel plates", International Journal of Heat and Mass Transfert, 1995, 38(10), 1893. [2] C. Suri, K. Tekenaka, H. Yanagida, Y. Kojima and K. Koyama, "Chaotic mixing generated by acoustic streaming", Ultrasonics, 2002, 40, 393 [3] O.V. Rudenko and A.A. Sukhorukov, "Nonstationnary Eckart streaming and pumping of liquid in ultrasonic field", Acoustical Physics, 1998, 44, 653. [4] Kenneth D. Frampton, Shawn E. Martin and Keith Minor, "The scaling of acoustic streaming for application in micro-fluidic devices", Applied Acoustics, 2003, 64,681

Dridi, Walid; Botton, Valery; Henry, Daniel; Ben Hadid, Hamda

270

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, Si3N4, SiB6, BN, Al4C3, Be2C) 3. multi-component systems of non-metallic materials with dominant heteropolar bonding (Al2O3, TiO2, BeO, SiO2, ZrO2). 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)

271

Blood circulation laboratory investigations with video are less investigative than instructional blood circulation laboratories with live organisms  

Science.gov (United States)

Live organisms versus digital video of the organisms were used to challenge students' naive ideas and misconceptions about blood, the heart, and circulatory patterns. Three faculty members taught 259 grade 10 biology students in a California high school with students from diverse ethnolinguistic groups who were divided into 5 classes using microscopes (128 students) and 5 classes using digital video (131 students) to compare blood transport among invertebrates, fish, and humans. The "What Is Happening in this Class?" (WIHIC) questionnaire was used for assessment of microscope and video groups to detect students' perception of their learning environment following these teaching interventions. The use of microscopes had a clear effect on the perception of the investigative aspects of the learning environment that was not detected with the video treatment. Findings suggest that video should not replace investigations with live organisms.

Ms. Mildred A. Hoover (Curtin Univ Technol)

2007-07-26

272

Experimental investigation of high temperature and high pressure coal gasification  

International Nuclear Information System (INIS)

Highlights: ? Gasification kinetics at temperature up to 1600 °C and pressure up to 0.5 MPa. ? Experimental investigation of pyrolysis under realistic conditions. ? Experiments in lab-scale using three different setups. ? Comparison of lab-scale data to experimental results from a pilot-scale gasifier. -- Abstract: Pyrolysis and gasification behavior is analyzed at operation conditions relevant to industrial scale entrained flow gasifiers. A wire mesh reactor and the Pressurized High Temperature Entrained Flow Reactor (PiTER) are used to measure volatile yield of Rhenish lignite, a bituminous coal and German anthracite at high temperature and high pressure. In the wire mesh reactor at 1000 °C a significant influence of pressure on volatile yield is observed. For lignite the volatile yield (daf) decreases from 57 wt% at atmospheric pressure to 53 wt% at 5.0 MPa. In the same pressure interval the volatile yield of the bituminous coal strongly decreases, whereas no significant influence of pressure on the volatile yield of anthracite is detected. In entrained flow experiments (PiTER) at higher temperature and 0.5 MPa an enhanced devolatilization of the lignite is observed. At 1200 °C, the maximum volatile yield is 62 wt% and it increases to 67 wt% at 1400 °C. In entrained flow gasification experiments with Rhenish lignite a high level of conversion is measured at atmospheric pressure and at 0.5 MPa. At both pressures, coal conversion increases with temperature and residence time. The highest conversion of 96 wt% is achieved at a particle residence time of 1.3 s, at a temperature of 1600 °C, and a pressure of 0.5 MPa. The experimental results show a large influence of operation parameters on pyrolysis and gasification behavior of Rhenish lignite. The volatile release in the pyrolysis stage and the high level of conversion after a short residence time indicate that Rhenish lignite is suitable for gasification in an entrained flow reactor. The reactivities of char samples that are collected from the hot reaction zone of the PiTER are measured in a pressurized thermogravimetric analyzer (PTGA) at lower temperature (600–850 °C). The pyrolysis temperature in the entrained flow experiments significantly influences the reaction rate in the PTGA at lower temperature. With increasing pyrolysis temperature (1200–1600 °C) a continuous loss of reactivity is observed.

273

Laboratory scale investigation of uranium melting and casting  

International Nuclear Information System (INIS)

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 14000C 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 12000C 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). (author)

274

An Investigation of Laboratory-Grown "Ice Spikes"  

CERN Document Server

We have investigated the formation of 10-50 mm long ``ice spikes'' that sometimes appear on the free surface of water when it solidifies. By freezing water under different conditions, we measured the probability of ice spike formation as a function of: 1) the air temperature in the freezing chamber, 2) air motion in the freezing chamber (which promotes evaporative cooling), 3) the quantity of dissolved salts in the water, and 4) the size, shape, and composing material of the freezing vessel. We found that the probability of ice spike formation is greatest when the air temperature is near -7 C, the water is pure, and the air in the freezing chamber is moving. Even small quantities of dissolved solids greatly reduce the probability of ice spike formation. Under optimal conditions, approximately half the ice cubes in an ordinary ice cube tray will form ice spikes. Guided by these observations, we have examined the Bally-Dorsey model for the formation of ice spikes. In this model, the density change during solidi...

Libbrecht, K G

2003-01-01

275

A European Network of Analytical and Experimental Laboratories for Geosciences: Challenges and Perspectives  

Science.gov (United States)

The EU policy for scientific research in the third millennium is that of a coordinated approach to support and develop continent-scale research infrastructures. The vision is to integrate the existing research infrastructures in order to increase the accessibility and usability of multidisciplinary data, enhancing worldwide interoperability by establishing a leading integrated European infrastructure and services. Integrating Earth Sciences infrastructures in Europe is the mission of the European Plate Observing System (EPOS), a research infrastructure and e-science for data and observatories on earthquakes, volcanoes, surface dynamics and tectonics. Within the existing core elements to be integrated in the EPOS cyber-infrastructure are: geographical distributed observational infrastructures (seismic and geodetic networks), observatories for multidisciplinary local data acquisition (e.g., volcanoes, active fault-zone, geothermal and deep drilling experiments), and analytical facilities for data repositories and integration. The integration of European analytical, experimental, and analogue laboratories plays a key role in this context and is the task of EPOS Working Group 6 (WG6). The Analytical and Experimental LaboratoriesGroup thus aims to link experimental, analytical, and analogue laboratories into a single, but geographically distributed, infrastructure for rock physics, including palaeomagnetism, analytical and experimental petrology and volcanology, and tectonic modeling.The WG6 has set a short term goal that has now been achieved, being a review of operational laboratory facilities in the community and the creation of a database from that information. Currently 12 countries (Germany, Greece, Ireland, Italy, Portugal, Romania, Slovenia, Spain, Sweden, Switzerland, The Netherlands, United Kingdom) are included in the database. As long-term goals, the WG6 aims to create mechanisms and procedures for easy access to laboratory facilities, turning small-scale infrastructures into a coherent, effective, and collaborative structure for European scientists. This will help increase coherence and efficiency of the European Experimental and Analytical Community and prepare us for the global challenges of the third millennium.

Freda, C.; Funiciello, F.; Meredith, P.; Sagnotti, L.; Scarlato, P.; Troll, V. R.; Willingshofer, E.; EPOS-WG6

2012-04-01

276

Experimental Investigation of a Morphing Nacelle Ducted Fan  

Science.gov (United States)

The application of Circulation Control to the nacelle of a shrouded fan is proposed as a means to enhance off-design performance of the shrouded fan. Typically, a fixed geometry shroud is efficient at a single operating condition. Modifying circulation about the fixed geometry is proposed as a means to virtually morph the shroud without moving surfaces. This approach will enhance off-design-point performance with minimal complexity, weight, and cost. Termed the Morphing Nacelle, this concept provides an attractive propulsion option for Vertical Take-off and Landing (VTOL) aircraft, such conceptual Personal Air Vehicle (PAV) configurations proposed by NASA. An experimental proof of concept investigation of the Morphing Nacelle is detailed in this paper. A powered model shrouded fan model was constructed with Circulation Control (CC) devices integrated in the inlet and exit of the nacelle. Both CC devices consisted of an annular jet slot directing a jet sheet tangent to a curved surface, generally described as a Coanda surface. The model shroud was tailored for axial flight, with a diffusing inlet, but was operated off-design condition as a static lifting fan. Thrust stand experiments were conducted to determine if the CC devices could effectively improve off-design performance of the shrouded fan. Additional tests were conducted to explore the effectiveness of the CC devices a means to reduce peak static pressure on the ground below a lifting fan. Experimental results showed that off-design static thrust performance of the model was improved when the CC devices were employed under certain conditions. The exhaust CC device alone, while effective in diffusing the fan exhaust and improving weight flow into shroud inlet, tended to diminish performance of the fan with increased CC jet momentum. The inlet CC device was effective at reattaching a normally stalled inlet flow condition, proving an effective means of enhancing performance. A more dramatic improvement in static thrust was obtained when the inlet and exit CC devices were operated in unison, but only over a limited range of CC jet momentum. Operating the nacelle inlet and exit CC devices together proved very effective in reducing peak ground plane static pressure, while maintaining static thrust. The Morphing Nacelle concept proved effective at enhancing off-design performance of the model; however, additional investigation is necessary to generalize the results.

Kondor, Shayne A.; Moore, Mark

2005-01-01

277

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

278

Experimental investigations of atmospheric pressure surface wave discharges  

International Nuclear Information System (INIS)

This work deals with microwave atmospheric pressure discharges sustained by surface waves in dielectric tubes. In such type of discharge the wave guiding structure for the traveling wave sustaining the plasma column is created by the wave itself, as the surface wave propagates along the interface between the plasma and the dielectric tube enclosing it. The aim of this work is to present results of experimental investigations of atmospheric pressure discharges in argon and neon, sustained in tubes of small (less than 5 mm) inner diameter. The discharge tubes were located within the cooling bath, and were enclosed in a cylindrical metal shield. Cooling of the discharge tube gives us the possibility of operation with the microwave power level of up to 4 kW. The plasma column length was measured versus absorbed microwave power for different discharge conditions. We also observed plasma column axial structure. This gives us a view on the wave propagation characteristics. Moreover, we present results of spectroscopic investigations of both the electron density and neutral gas temperature. The electron density in the surfaguide plasma was determined using the method based on the Stark broadening of Hb spectral line. The neutral gas temperature in the surfaguide plasma was determined by comparing measured and calculated spectra of the OH radicals. A small amount (about 0.2 % vol.) of water vapour was added to the working gas as a source of H atoms and OH radicals. The spectroscopic results we shall use developing of a model of propagation of surface wave. Propagation characteristics of the wave were calculated using two-temperature model of a microwave discharge. The dependence of the plasma column length on absorbed power is determined. (author)

279

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

280

Experimental investigation of hydraulic criteria in the fishways  

International Nuclear Information System (INIS)

Migratory Fish travel downstream to reach larger body of water where the food is available. When they grows, migrate upstream to the place of their birth to spawn. In areas where fish have a commercial value and to keep alive these species as a part of environment, care must be done not to stop such migration specially by constructing the dams across the rivers. Diversion dams usually built across the river to divert some portion of the river flow for irrigation lands. In such dams, the engineers must provide a passage called 'FISHWAY'; for fish in order that fish can travel from down stream to the upstream of the dam. Of course, if such structure is not considered, the fish can not travel upstream to spawn, therefore in the long term these species will diminish. In this study a hydraulic model was conducted to investigate the hydraulic conditions of a vertical-slot type of fishway which has been considered for Ramhormoz diversion dam in the province of Khouzestan, Iran. The Froudian hydraulic model with the scale of 1:5 was constructed at the hydraulic laboratory of Shahid Chamran University. Tests were performed for the original design and two other alternatives slot-opening angles. Another fishway called Denil, also was tested. From the observation and data obtained from these tests, it was found that 90-degree slot opening provide suitable hydraulic conditions. Denil fishway also was found to satisfy the hydraulic criteria and due its simplicity and rapid construc and due its simplicity and rapid construction was recommended to be used in this diversion dam. (author)

281

Significance of different animal species in experimental models for in vivo investigations of hematopoiesis  

Directory of Open Access Journals (Sweden)

Full Text Available Numerous discoveries in medicine are results of experiments on different animal species. The most frequently used animals in hematopoiesis investigations are laboratory mice and rats, but so-called big animals, such as pigs, sheep, cats, dogs, and monkeys, evolution-wise closer to humans have a place in experimental hematology as well. The specific problematics of a certain animal specie can lead to fundamental knowledge on certain aspects of the process of hematopoiesis end the biology of stem cells in hematopoiesis. Furthermore, comparative investigations of certain phenomena in different species help in the recognition of the general rules in the living world. In the area f preclinicalinvesti- gations, animal models are an inevitable step in studies of transplantation biology of stem cells in hematopoiesis, as well as in studies of biologically active molecules which have an effect on the hematopoietic system. Knowledge acquired on animal models is applied in both human and veterinary medicine.

Kova?evi?-Filipovi? Milica

2004-01-01

282

Results of experimental investigations of cobalt beta decay rate variation  

CERN Document Server

Results of long-term investigations of variation of cobalt beta decay rate from 28.12.2010 till 08.02.2012 are presented. The scintillation spectrometer with two LaBr3 detectors is used to register of gamma-quanta with energy 1.173 and 1.332 MeV accompanying cobalt beta decay. Counting rate of each detector and their gamma-quanta coincidence are collected in successive time intervals 10 s. The statistical Kolmogorov-Smirnov method for data analysis is used. Temperature influence on experimental results is also analyzed. Deviations of beta decay counting rate from constant distribution during the days were detected in those decades: from 11.03 to 21.03 with significance level a = 0.1; from 22.04 to 02.05 with a=0.0125; from 24.06 to 04.07 with a=0.05; from 04.08 to 14.08 with a=0.05.

Baurov, Yu A; Baurov, A Yu; Nikitin, V A; Dunin, V B; Tihomirov, V V; Sergeev, S V; Demchuk, N A

2013-01-01

283

Experimental investigation of statistical models describing distribution of counts  

International Nuclear Information System (INIS)

The binomial, Poisson and modified Poisson models which are used for describing the statistical nature of the distribution of counts are compared theoretically, and conclusions for application are considered. The validity of the Poisson and the modified Poisson statistical distribution for observing k events in a short time interval is investigated experimentally for various measuring times. The experiments to measure the influence of the significant radioactive decay were performed with 89Ym(T1/2=16.06 s), using a multichannel analyser (4096 channels) in the multiscaling mode. According to the results, Poisson statistics describe the counting experiment for short measuring times (up to T=0.5T1/2) and its application is recommended. However, analysis of the data demonstrated, with confidence, that for long measurements (T?T1/2) Poisson distribution is not valid and the modified Poisson function is preferable. The practical implications in calculating uncertainties and in optimizing the measuring time are discussed. Differences between the standard deviations evaluated on the basis of the Poisson and binomial models are especially significant for experiments with long measuring time (T/T1/2?2) and/or large detection efficiency (?>0.30). Optimization of the measuring time for paired observations yields the same solution for either the binomial or the Poisson distribution. (orig.)ibution. (orig.)

284

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

285

The microbiological swab sampler--a quantitative experimental investigation.  

Science.gov (United States)

The aim of the investigation was to give an in vitro experimental account of the commonly used cotton swab as a sampler for quantitative determination of bacteria in operation wounds. The transfer of staphylococci with the swab from an inoculated to a non-inoculated agar culture plate was used as a model, and three different ways of swab handling were tested. A direct transfer of 19 per cent staphlococci from the inoculated to the non-inoculated plate was found. When the swab was rinsed in a small volume of saline and the rinsing fluid was plated, 39 per cent were transfered. When the swab was kept in a Stuart transport medium, as is the usual procedure in clinical practice, only 4 per cent were transfered. Quantitative wound swab cultures depend on a thorough sampling of the wound and an efficient recovery of bacteria from the swab. It is concluded that the use of a Stuart transport medium would appear to hamper quantitative determination, and a rinsing procedure should be preferred. PMID:364927

Nyström, P O

1978-12-01

286

Experimental and theoretical investigations of a 17 GHz RF gun  

CERN Document Server

We report on experimental and theoretical investigations of a 17 GHz RF photocathode electron gun. This is the first photocathode electron gun to operate at a frequency above 2.856 GHz. The 1.5 cell, pi mode, copper cavity was tested with 50 ns pulses from a 17.150 GHz klystron amplifier built by Haimson Research Corp. A Bragg filter was used at the RF gun to reduce the reflection of parasitic modes back into the klystron. Coupling hole theory in conjunction with cold test measurements was used to determine the field profile in the RF gun. The particle in cell code MAGIC as well as coupled envelope equations were used to simulate the beam dynamics in the RF gun. With power levels of 4 MW, the on axis electric field at the cathode exceeds 300 MV/m, corresponding to an average accelerating gradient of 200 MV/m over the first half cell of the gun. Breakdown was observed at power levels above 5 MW. Electron bunches were produced by 20 mu J, 1 ps UV laser pulses impinging on the RF gun copper photocathode and were...

Brown, W J; Kreischer, K E; Pedrozzi, M; Shapiro, M A; Temkin, R J

1999-01-01

287

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.

288

An experimental investigation of high-aspect-ratio cooling passages  

Science.gov (United States)

An experimental investigation was conducted to evaluate the effectiveness of using high-aspect-ratio cooling passages to improve the life and reduce the coolant pressure drop in high-pressure rocket thrust chambers. A plug-nozzle rocket-engine test apparatus was used to test two cylindrical chambers with low-aspect-ratio cooling passages and one with high-aspect-ratio cooling passages. The chambers were cyclically tested and data were taken over a wide range of coolant mass flows. The results showed that for the same coolant pressure drop, the hot-gas-side wall temperature of the high-aspect-ratio chamber was 30 percent lower than the baseline low-aspect-ratio chamber, resulting in no fatigue damage to the wall. The coolant pressure drop for the high-aspect-ratio chamber was reduced in increments to one-half that of the baseline chamber, by reducing the coolant mass flow, and still resulted in a reduction in the hot-gas-side wall temperature when compared to the low-aspect-ratio chambers.

Carlile, Julie A.; Quentmeyer, Richard J.

1992-01-01

289

Experimental investigation of thermocapillary effect on drop evaporation  

Science.gov (United States)

A space experiment is prepared to fly aboard Chinese recoverable satellite in the near future, focusing on the interfacial phenomena and the effect of thermocapillary convection on the heat and mass transfer and, thereby, the evaporating rate in drop evaporation process. Close attention will also be paid to the contact angle behavior, the triple line shifting and their relations The space experiment setup and its functions and our ground-based experiment results are presented in here The interior flow field and the gaseous exterior of evaporating drops were observed. The temperature distributions inside and outside the drop were measured. Both good heat conductor and heat insulating material were used as substrate materials to investigate their influence on the surface temperature distribution Experimental results indicate that for a drop evaporating in ambient temperature without substrate heating, temperature gradient existed on the drop surface which results in a stable thermocapillary convection Cells appeared near the surface throughout entire evaporating process. The thermocapillary convection greatly changed the temperature distribution in the drop and the way energy and mass transfer. Temperature jump or discontinuity was found at drop free surface.

Xie, Jingchang; Lin, Hai

2013-03-01

290

Experimental investigation of the dynamics of spinning tethered bodies  

Science.gov (United States)

Ground based experiments are conducted as a part of the OEDIPUS-C sounding rocket mission, scheduled for launch in the winter of 1995. Here OEDIPUS stands for Observation of Electrified Distribution in Ionospheric Plasma—a Unique Strategy. The OEDIPUS-C configuration consists of two spinning bodies connected by a 1 km long tether (the spin axis is nominally along the tether line). The objective is to assess dynamic behaviour of the tether and the payload. The test configuration consists of an end-body supported by a tether. The test procedure involves slow spin-up of the system and identifying the speeds corresponding to onset of the tether modes or the large amplitude end-body coning. This is referred to as the critical speed and corresponds to the stability boundary of the system. Experimental results are obtained for four different bodies to study the system stability over a wide range of mass and geometric parameters. Effect of offset of the tether attachment from the end-body centre of mass is also investigated. The observed critical speeds are compared with those given by the linear theory. The test results are generally in very good agreement with the theory, however several transient phenomena observed during the test suggest that system nonlinearities cannot be ignored when modelling such a complex system.

Modi, V. J.; Pradhan, S.; Chu, M.; Tyc, G.; Misra, A. K.

1996-10-01

291

Experimental investigation of mixed convective flow over a wavy wall  

International Nuclear Information System (INIS)

An experimental study is carried out to address mixed convection from a heated wavy surface. The channel flow between the sinusoidal surface and a flat top wall is investigated by means of a combined digital particle image velocimetry (DPIV) and planar laser-induced fluorescence (PLIF) technique to examine the spatial variation of the streamwise and wall-normal velocity components, and to assess the concentration field of a tracer dye injected into the fluid. We discuss the influence of mixed convection on turbulence quantities and scalar transport properties. Due to the influence of mixed convection we find asymmetric mean velocity profiles and increased momentum transport in the vicinity of the heated surface. The transport of the tracer dye is characterized by enhanced vertical transport due to buoyancy effects and enhanced spanwise transport due to the presence of longitudinal flow structures induced by the mixed convection. We identify two dominant scalar structures with the most influence on vertical transport. The first one is induced by buoyancy effects, the second one by a combination of buoyancy effects and local wall curvature. Thus the transport properties are additionally enhanced compared to mixed convection from a flat plate by the presence of the wavy surface

292

Experimental investigation of Fast ions transport in TORPEX  

International Nuclear Information System (INIS)

Full text: In fusion machines, fast ions may be introduced by ICRH, NBI and burning plasma sources. Fast ion transport in interchange-dominated plasmas is investigated in the basic toroidal plasma device TORPEX. The experimental setup consists of a miniaturized lithium 6+ ion source, which emits fast ions with energies up to 1 KeV, and a double gridded energy analyzer mounted on a 2D movable system. A toroidally movable system for the fast ions source, allowing the reconstruction of the 3D fast ions profile, is presently under development. The fast ions current profile is measured using synchronous detection by applying a modulated biasing voltage to the source. An analog lock-in amplifier has been developed, which allows removing capacitive noise due to the modulation. In the 2D configuration, we can characterize both vertical and radial transport of the fast ions, influenced by the magnetic field geometry and plasma perturbations from the ideal interchange instability. Preliminary results and future developments will be discussed. (author)

293

Fatigue crack closure under triaxial stress constraint. 1: Experimental investigation  

Science.gov (United States)

Experimental investigation has been done for fatigue crack closure in 7050-T7451 aluminum alloy and 30CrMnSiNi2A high strength steel. CT specimens with thicknesses of 2, 3, 4, and 8 mm are used and four techniques of closure measurement are adopted in the test, namely the COD-load compliance technique, back face strain-load compliance technique, near tip strain gauge technique, and the indirect technique based on fatigue crack propagation rate (FCPR) measurement. The uncertainties associated with different techniques of closure measurement as well as the thickness effects are analyzed. It is shown that the global-compliance based methods cannot reflect the shielding effect of closure upon the crack tip strain intensification sufficiently. The near tip strain gauge method is more sensitive and can give a better result if the gauge lies in an optimum position. For materials in which the striation mechanism is dominant the indirect methods based on FCPR or fatigue striation measurement can predict the closure level very well.

Wanlin, Guo

1994-09-01

294

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

295

Experimental Investigation on Effect of Adhesives on Thermoelectric Generator Performance  

Science.gov (United States)

Thermoelectric generators (TEGs) convert heat energy into electricity. Currently, these devices are attached to heat exchangers by means of mechanical devices such as clamps or fixtures with nuts and bolts. These mechanical devices are not suitable for use in harsh environments due to problems with rusting and maintenance. To eliminate the need for such mechanical devices, various kinds of adhesives used to attach thermoelectric generators to heat exchangers are investigated experimentally in this work. These adhesives have been selected based on their thermal properties and also their stability to work in harsh environments to avoid damage to the integrity of the attachment over long periods of time. Stainless-steel plates were attached to a thermoelectric generator using the adhesives. The introduction of the adhesive as a means of attachment for thermoelectric generators contributes to increase the thermal resistance to heat transfer across the TEG. The adhesive layers increased the thermal resistance of the thermoelectric generator by 16% to 109%. This work examines the effect of the adhesives on the thermal performance and power output of a single thermoelectric generator for various heat inputs.

Singh, Baljit; Remeli, Muhammad Fairuz; Chet, Ding Lai; Oberoi, Amandeep; Date, Abhijit; Akbarzadeh, Aliakbar

2015-01-01

296

Experimental investigation of sound absorbers based on microperforated panels  

Science.gov (United States)

Microperforated panels have been studied as a good, interesting absorbing element. In previous papers the properties of high absorption obtained in a wide frequency band was demonstrated, based on the impedance of the very small perforations. The perforation area ratio, the diameter of the holes, the thickness of the panel, and the density and viscosity of the air are the terms that define the sound absorption provided by the element. The microperforated panels have a simple structure and it is possible to build single or double resonators, in order to obtain a wide band response. An orifice may be considered as a short tube. Many years ago, Rayleigh and Crandall studied the propagation of sound in small tubes, of a very short length compared to wavelength. They found a high acoustics resistance and a very small reactance. So, the microperforated panel can be used as a dissipative element. An experimental investigation was carried out on different samples of microperforated panels, in order to obtain their sound absorption coefficient and so verify the validity of the mathematical models. Microperforated panels have been developed to cover a welding cabin internally, where classical absorbents are useless. (To be presented in Spanish.)

Vechiatti, Nilda S.; Mendez, Antonio M.; Gimenez de Paz, Juan C.

2002-11-01

297

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

298

Numerical and experimental investigation of thermosyphon solar water heater  

International Nuclear Information System (INIS)

Highlights: • We studied a thermosyphon solar water heater composed of high-performance components. • A differential equations solution technique is investigated. • The influences of the collector and storage losses on the system performance were examined. • The storage losses have more influence on the long-term performance. - Abstract: A glassed flat plate collector with selective black chrome coated absorber and a low wall conductance horizontal storage are combined in order to set up a high performance thermosyphon system. Each component is tested separately before testing the complete system in spring days. During the test period, effect of different inlet water temperatures on the collector performance is studied and results have shown that the collector can reach a high efficiency and high outlet water temperature even for elevated inlet water temperatures. Subsequently, long term system performance is estimated by using a developed numerical model. The proposed model, accurate and gave a good agreement with experimental results, allowed to describe the heat transfer in the storage. It has shown also that the long-term performances are strongly influenced by losses from the storage than losses from the collector

299

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

300

Experimental investigation of boundary layer ingestion into diffusing inlets  

Science.gov (United States)

An experimental investigation was carried out to examine the flow inside diffuser inlets ingesting boundary layers with a thickness of the order of 30-40% of the ducts' throat height, with and without passive flow control consisting of vortex generators (vg's). The first of the three ducts tested was a long semi-circular diffusing duct with no offset. It was examined to study vortical. dynamics in internal flows and the effect of various vg design parameters on their performance and impact on the flow structure inside the diffuser. The other two ducts were shorter than the first duct and both had the same length and diffusion ratio. One duct maintained a semi-circular cross-section throughout its length with no offset, and the second one had an S-shaped offset and changed its cross-section from a semi-circle at the throat to a full circle at the fan face. The flow surveys in the two ducts were compared to understand the effect of offset on flow structure, diffuser performance and vg effectiveness. Duct performance was quantified in terms of pressure recovery and total pressure distortion at the fan face (exit) of the duct. The S-duct also yielded results applicable to aircraft engine inlets as its geometry was similar to that expected on the inlets of the NASA/Boeing Blended-Wind-Body (BWB).

Anabtawi, Amer Jamal

301

Experimental investigation of mesoscale crack front triple line  

Science.gov (United States)

The aim of this paper is to investigate the mesoscale behavior and structure of an adhesive near the fracture front of an asymmetric joint consisting of carbon fiber/epoxy resin composites bonded with a relatively soft, epoxy adhesive. A single cantilever beam fracture test at constant separation rate gave steady-state crack propagation, details of which were followed by digital image correlation (DIC). A deformed, triple line region was found between the adhesive, air, and the composite, somewhat resembling a "wetting ridge," as found with a liquid meniscus in contact with a soft solid. Importantly, the partially separated bondline layer took part in (non-unidirectional) load transfer between adherends (and thus energy dissipation), contrary to common assumptions where the separated bondline is assumed no longer to play a structural role. A simple model, based on the Flamant contact mechanics approach, is proposed and compared with both a finite element solution and experimental data extracted from image correlation. The model points out the importance of two length scales: process zone extent and adhesive thickness, both being known to affect global properties of bonded structures.

Budzik, Michal K.; Jumel, Julien; Shanahan, Martin E. R.

2014-02-01

302

Computerised protocols for laboratory investigation and their effect on use of medical time and resources.  

OpenAIRE

AIMS: To devise a computerised management system protocol which not only proposes the laboratory investigations to be performed on each patient but also performs related clinical functions. METHODS: The system was designed by senior members of staff. The protocols defined all laboratory investigations including haematology, biochemistry, immunology and cross-matching, and included static and dynamic rules. Patients can be changed to different or additional protocols, as required; likewise pro...

Mutimer, D.; Mccauley, B.; Nightingale, P.; Ryan, M.; Peters, M.; Neuberger, J.

1992-01-01

303

Flow cytometric investigation on degradation of macro-DNA by common laboratory manipulations  

OpenAIRE

The degree and characteristics of physical degradation of macro-DNA molecules by common laboratory manipulations are reported. With linearized lambda-phage viral DNA as the model DNA, fragmentation of macro-DNA by various indispensable laboratory manipulations were investigated using a high sensitivity flow cytometric setup. Investigated manipulations included pipetting, vortexing, rocking, freeze-thawing, ultrasonication and ultrafiltration. “Exhaustive counting” of the intact lambda DNA...

Sang-Ryoul Park; Hee-Bong Yoo; Hyuk-Min Lim; Inchul Yang; Sook-Kyung Kim

2011-01-01

304

Experimental investigation of reinforced-concrete Category I structures at high load levels  

International Nuclear Information System (INIS)

A US Nuclear Regulatory Commission-funded experimental program designed to obtain information on the structural behavior of reinforced-concrete buildings has been underway at the Los Alamos National Laboratory since 1980. This information will aid the NRC in evaluating the seismic capacities of existing Seismic Category I buildings. Scale models of reinforced-concrete shear walls and buildings were subjected to static and dynamic tests. Simulated seismic tests were conducted on model structures constructed to two scales (1/30 and 1/10), permitting an evaluation of the effect of scale in experimental investigations of reinforced-concrete structures. Monotonic and cyclic quasistatic tests provide information on strength, stiffness, strength and stiffness degradation, ductility, and general load-deflection behavior up to the ultimate load. The dynamic tests yielded information on natural frequencies, equivalent viscous damping values, initial stiffness and stiffness degradation, and general response behavior. These experimental investigations have indicated that sine-sweep tests are not suitable for reinforced-concrete structures and that the initial stiffness of shear wall structures is less than predicted when assuming an uncracked concrete section

305

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

306

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

307

Experimental and Computational Investigations of Strain Localization in Metallic Glasses  

Science.gov (United States)

Metallic glasses are metallic alloy systems with disordered atomic structure. Due to their unique amorphous structure, they exhibit an extraordinary set of properties that are ideal for a wide variety of applications ranging from electrical transformers, armor-piercing projectiles, sporting goods and fuel cells to precision gears for micromotors. In particular, owing to their exceptional mechanical properties like near-theoretical strength (1--3 GPa), large elastic strain range (2--3%), and unusual formability above the glass transition temperature, metallic glasses have tremendous potential in structural applications. Unfortunately, their unique structure also gives rise to significant limitations, such as limited ductility at room temperature due to rapid localization of plastic flow in shear bands. However, when the test volumes approach the size of a shear band nucleus (˜50--500 nm), it is believed that shear band formation and propagation can be constrained, leading to enhanced plasticity and failure strength. This study investigates the phenomenon of strain localization using both experimental and computational techniques. On the experimental front, sample size effects on strength, plasticity and deformation modes were explored in a Zr-based bulk metallic glass via micron- and sub-micron scale compression testing. Specimens with diameters ranging from 200 nm to a few microns were fabricated using Focused Ion Beam technique and were tested under uniaxial compression in a nanoindentation set-up with a flat punch tip. Effect of extrinsic factors like specimen geometry and machine stiffness on deformation behavior was discussed. Shear banding was shown to be more stable at this length scale than in macro-scale testing because of a smaller specimen to load frame stiffness ratio. It was found that as the specimen size is reduced to below 300 nm, the deformation mode changes from being discrete and inhomogeneous to more continuous flow including both localized and non-localized contributions at low strains. Moreover, the magnitude of strain bursts was found to decrease with decrease in specimen size. Furthermore, Weibull statistical analysis was performed to investigate the effect of specimen size on yield strength in this metallic glass. It was revealed that the dispersion in strengths increases dramatically with decrease in sample size, attributed to the size distribution of the defects responsible for shear banding. The findings are crucial in designing systems which promote plasticity in metallic glasses by suppressing the shear-band instability and also in direct application of these materials for structural purposes as small components in micro- and nano-scale systems. On the computational front, Molecular Dynamics (MD) simulations have been employed to generate Zr-Cu metallic glass structures. In order to analyze and better understand and visualize the concepts of "free" volume and flow defects in metallic glasses, an electron density model was developed as an upgrade to the traditional hard sphere approaches. Simple tension and shear modes of deformation were simulated using MD in Zr-Cu system, and role of open volume in deformation was studied using the electron density model. In uniaxial tension simulations, effect of temperature and deformation rate is examined, and the process of accumulation of free volume to the point of catastrophic failure is visualized using the Electron Density model. In shear simulations, we find that the as-quenched glass structures undergo homogeneous deformation and do not exhibit any strain localization. However, it is found that by incorporating a cylindrical void in the glass structure as a source of "free" volume, it is possible to induce strain localization. It was found that a critical void diameter of 8A was required to successfully initialize strain localization in this system.

Bharathula, Ashwini

308

Experimental Investigation on the Melt Pool Configuration with the COSMOS  

Energy Technology Data Exchange (ETDEWEB)

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

Kang, Kyoung Ho; Park, Rae Joon; Park, Hee Dong; Hong, Seong Ho; Hong, Seong Wan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2011-10-15

309

Experimental and theoretical investigations of a 17 GHz RF gun  

International Nuclear Information System (INIS)

We report on experimental and theoretical investigations of a 17 GHz RF photocathode electron gun. This is the first photocathode electron gun to operate at a frequency above 2.856 GHz. The 1.5 cell, ? mode, copper cavity was tested with 50 ns pulses from a 17.150 GHz klystron amplifier built by Haimson Research Corp. A Bragg filter was used at the RF gun to reduce the reflection of parasitic modes back into the klystron. Coupling hole theory in conjunction with cold test measurements was used to determine the field profile in the RF gun. The particle in cell code MAGIC as well as coupled envelope equations were used to simulate the beam dynamics in the RF gun. With power levels of 4 MW, the on axis electric field at the cathode exceeds 300 MV/m, corresponding to an average accelerating gradient of 200 MV/m over the first half cell of the gun. Breakdown was observed at power levels above 5 MW. Electron bunches were produced by 20 ?J, 1 ps UV laser pulses impinging on the RF gun copper photocathode and were measured with a Faraday cup to have up to 0.1 nC of charge. This corresponds to a peak current of about 100 A, and a density at the cathode of 8.8 kA/cm2. Multiple output electron bunches were obtained for multiple laser pulses incident on the cathode. Phase scans of laser-induced electron emission reveal an overall phase stability of better than ±20 deg. , corresponding to ±3 ps synchronization of the laser pulses to the phase of the microwave field.s to the phase of the microwave field. A Browne-Buechner magnetic spectrometer indicated that the RF gun generated 1 MeV electrons with a single shot rms energy spread of less than 2.5%, in good agreement with theoretical predictions

310

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 ofed for the initial melt pool conditions of the major severe accident sequences of the APR1400

311

Experimental investigation of elliptically polarized injection-locked VCSELs  

Science.gov (United States)

Polarization switching (PS) between linear polarizations of a vertical-cavity surface-emitting laser (VCSEL) can appear when this device is subject to orthogonal optical injection. In this type of injection the injected field has a linear polarization orthogonal to that of the free-running VCSEL. In this situation interesting nonlinear dynamics appear, one of which is the existence of an injection-locked solution for which the two linear polarized modes of the VCSEL lock to the master laser frequency. This situation has been theoretically predicted and corresponds to an elliptically polarized injection-locked (EPIL) state. In this paper we report an experimental investigation of the dynamics of a long-wavelength single-transverse mode VCSEL subject to orthogonal optical injection. The free-running VCSEL emits a linearly polarized beam in the so called "parallel" direction. The polarization of the injected light is perpendicular to this state and is termed "orthogonal" polarization. We observe the EPIL state when the frequency of the orthogonal injected light is near the frequency of the parallel polarization. The spectral feature of the EPIL state is verified and the power of each polarization is measured. The EPIL region is measured in the frequency detuning-injected power plane. As current decreases, the frequency detuning range for the EPIL to exist is narrower and shifts toward the negative frequency detuning. Periodic dynamics in which both polarizations oscillate with a frequency very close to the relaxation oscillation frequency is found above the upper boundary of the EPIL region. Below the lower boundary of the EPIL zone, periodic dynamics is found only in the parallel polarization.

Lin, Hong; Pérez, Pablo; Valle, Angel; Pesquera, Luis

2014-05-01

312

Experimental and computational investigation of local scour around bridge piers  

Science.gov (United States)

Experiments and numerical simulations are carried out to study clear-water scour around three bridge piers with cylindrical, square, and diamond cross-sectional shape, respectively. To handle movable-bed channels with embedded hydraulic structures, the fluid-structure interaction curvilinear immersed boundary (FSI-CURVIB) method is employed. The hydrodynamic model solves the unsteady Reynolds-averaged Navier-Stokes (URANS) equations closed with the k-? turbulence model using a second-order accurate fractional step method. Bed erosion is simulated by solving the sediment continuity equation in the bed-load layer using a second-order accurate unstructured, finite-volume formulation with a sand-slide, bed-slope-limiting algorithm. Grid sensitivity studies are carried out to investigate the effect of grid resolution on the predictive capability of the model. Comparisons of the simulations with the experimental data show that for all three cases the agreement is reasonable. A major finding of this work, however, is that the predictive capability of the URANS morphodynamic model improves dramatically for the diamond shape pier for which sediment transport is driven primarily by the shear layers shed from the pier sharp edges. For piers with blunt leading edge, on the other hand, as the circular and square shapes, the URANS model cannot resolve the energetic horseshoe vortex system at the pier/bed junction and thus significantly underpredicts both the scour depth at the nose of the pier and the rate of scour growth. It is also shown that ad hoc empirical corrections that modify the calculated critical bed shear stress to enhance scour rate in the pier leading edge need to be applied with caution as their predictive capabilities are not universal but rather depend on the pier shape and the region of the flow.

Khosronejad, Ali; Kang, Seokkoo; Sotiropoulos, Fotis

2012-03-01

313

Numerical modelling of saltwater up-coning: Comparison with experimental laboratory observations  

Science.gov (United States)

SummaryIn this study, previous interpretations of the density-dependent flow and transport processes induced by pumping freshwater above denser saltwater in four laboratory sand-tank experiments are extended using numerical modelling. The numerical model captured the transition in dispersiveness of up-coning plumes observed in the laboratory (i.e. highly dispersive at early times tending to sharp-interfaces after saltwater reaches the well). This demonstrates the applicability of the velocity-dependent dispersion of the modelling code. In all four experiments, head-dependent flux boundary conditions were used to simulate the sand-tank side boundary conditions. The experimentally derived boundary conductance values indicate non-linear variations in the resistance to flow through side inflow ports between the different experiments. Nonetheless, linear boundary head-inflow relationships adequately reproduced laboratory up-coning. The numerical model was able to reproduce the laboratory results within a reasonable level of accuracy and with minimal calibration of model parameters for three of the four experiments. This serves to validate those particular laboratory observations. The "double-peak" up-coning observed late in the fourth laboratory experiment was not reproduced by the model. Further analysis considering adsorption of the Rhodamine tracer is suggested to explore the cause of this effect. Numerical modelling results were compared to an existing sharp-interface analytical solution, which corresponded well with the numerical modelling results for early stages of the four up-coning experiments, despite the dominant influence of dispersion at early times.

Jakovovic, Danica; Werner, Adrian D.; Simmons, Craig T.

2011-05-01

314

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)

315

Theoretical and experimental investigation of the characteristics of moving melt  

International Nuclear Information System (INIS)

Results of calculations of velocity fields and time characteristics of flow of aluminum melt in a sand-loam casting mold are provided. The experimental data on time characteristics of flowing (moving) melt are obtained. Comparison is made of the experimental and theoretical data

316

ITER (International Thermonuclear Experimental Reactor) magnet development program at LLNL (Lawrence Livermore National Laboratory)  

Energy Technology Data Exchange (ETDEWEB)

The International Thermonuclear Experimental Reactor (ITER) magnet development program at Lawrence Livermore National Laboratory mainly involves developing high-performance, radiation-tolerant magnet concepts. Model coils, full-scale conductors, and insulation systems will be fabricated and tested. This paper briefly describes the program plan. Also included is the description of the Fusion Engineering International Experimental Magnet Facility (FENIX) which is currently under construction for testing full-scale ITER conductors to 40 kA and 14 T. Its design parameters and schedule are reviewed. 2 refs., 2 figs., 1 tab.

Shen, S.S.

1989-09-01

317

ITER [International Thermonuclear Experimental Reactor] magnet development program at LLNL [Lawrence Livermore National Laboratory  

International Nuclear Information System (INIS)

The International Thermonuclear Experimental Reactor (ITER) magnet development program at Lawrence Livermore National Laboratory mainly involves developing high-performance, radiation-tolerant magnet concepts. Model coils, full-scale conductors, and insulation systems will be fabricated and tested. This paper briefly describes the program plan. Also included is the description of the Fusion Engineering International Experimental Magnet Facility (FENIX) which is currently under construction for testing full-scale ITER conductors to 40 kA and 14 T. Its design parameters and schedule are reviewed. 2 refs., 2 figs., 1 tab

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 2009 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 2009 fiscal year (2009/2010). 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 2009 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)

320

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)

321

Laboratory investigations of the hardening of fuel briquettes in fluidized sand beds  

Energy Technology Data Exchange (ETDEWEB)

A laboratory apparatus for investigating hardening of briquettes is described. The hardening of briquettes made from semi-coke and a binder was investigated in the temperatue range 200 - 350 C, with hardening times of 15 to 75 minutes. The characteristics of the briquettes obtained are discussed. (In Polsih)

Dreszer, K.; Plaskura, W.; Wegiel, J.

1978-07-01

322

Experimental investigation of earthquake precursory slip pulses and accelerating creep  

Science.gov (United States)

Earthquake nucleation on pre-existing surfaces is governed by frictional instabilities which can be described by state parameters. These parameters may evolve with cumulative slip and progressive acceleration eventually driving the system to catastrophic failure under a given far-field stress. Studying the transition towards catastrophic failure requires stress-controlled experiments, where the dependent variable is the strain accommodated by the slipping zone, and the experimental setting is sensitive enough to allow and detect strain changes. A majority of previous experiments carried out to investigate stick-slip and stable sliding were conducted under strain-rate controlled conditions with biaxial or triaxial apparatus that have limited total slips (usually torque) is gradually increased on the sliding surface until spontaneous slip occurs, at which point the shear stress is maintained and the strain and strain rate are left to evolve whilst being continuously monitored. Experiments were performed at room temperature under room-humidity and vacuum (10E-3 mbar) conditions on micro-gabbro, granite, and calcite marble imposing a constant normal load of 20 MPa. In micro-gabbro, increasing the torque equivalent to a friction coefficient, ?, of 0.2 resulted in spontaneous slip pulses of 4-12 cm with velocity peaks of 6-60 cm/s. Slip pulses coincided with sample dilation. Once a critical torque threshold (?~0.7) was overcome, slip rates increased to the imposed limiting speed (3m/s), and melt lubrication occurred with friction decaying exponentially to a lower steady-state value (?~0.1). In granite, prior to the onset of the main slip weakening event the spontaneous slip pulses intensified in a regular manner (velocity peaks up to 0.3 mm/s and slips up to 0.1 mm). They accommodated a total slip of 1.8 mm without significant sample dilation. In calcite marble, spontaneous accelerating creep without sample dilation started at ?~0.65. A first creep episode proceeded at 0.3 mm/s and a second slower event at 0.02 mm/s. The second event eventually led to the main slip weakening, when slip rate increased progressively, fault lubrication occurred and friction decayed exponentially to ?~0.03. These results show firstly that slip weakening results in catastrophic failure, and secondly that precursory slip episodes may contain a detectable pattern that is specific to rock composition.

Spagnuolo, E.; Nielsen, S. B.; Smith, S.; Violay, M. E.; Niemeijer, A. R.; Di Toro, G.; Di Felice, F.

2011-12-01

323

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

324

Experimental Investigation on Strength Characteristics of Binary Blended Concrete  

Directory of Open Access Journals (Sweden)

Full Text Available An experimental investigation has been carried out to assess the behavior of concrete beams blended with steel crimped fiber and flyash subjected to combined torsion-bending-shear with longitudinal reinforcement. The concrete is binary blended with 15% of fly ash by weight of cement as partial replacement of cement and addition of 0%, 0.5%, 0.75%, 1% of crimped steel fibers with aspect ratio of 80 are used for the study purpose. Compressive strength of concrete is measured by testing standard cubes (150mm x 150mm x 150mm at the age of 28 days, the combined torsion-bending-shear strength is measured by testing beams of size 100x100mm and length 1200mm with a bracket attached at center of size 100x100x300mm.This bracket is adequately reinforced to avoid any failure at joint. The tests were conducted on 12 beams for varying percentages of steel fibers and studied for their behavior under combined torsion-bending-shear. The study involved the influence of fiber addition on the ultimate torsion-bending-shear strength of beams.Test results indicated that fibrous concrete beams exhibited improved overall performance with respect to corresponding non-fibrous beams. Flyash with steel fiber has shown considerable improvement in the compressive and torsion-bending-shear strength of concrete. From the test results it is observed that the concrete mix with 15% fly ash replacement of cement of M30 grade concrete mixture has shown maximum compressive strength of 47 MPa at 28 days. Concrete mixture with 15% fly ash replacement of cement along with 0.75% of crimped steel fibers has shown significant improvement in various properties at the age 0f 28 days indicated by 38% increase in compressive strength and 58% increase in the combined torsion-bending-shear strength of concrete. Hence binary blended crimped steel fiber reinforced concrete with 15% fly ash with 0.75 % steel fibers is a novel material having superior performance characteristics compared with conventional concrete.

MD. Hashmath

2014-12-01

325

Experimental and Numerical Investigation of Flow under Sluice Gates  

OpenAIRE

The flow characteristics upstream and downstream of sluice gates are studied experimentally and numerically using Reynolds averaged Navier-Stokes two-dimensional simulations with a volume of fluid method. Special attention was brought to large opening and submergence, a frequent situation in distribution canals that is little seldom addressed in the literature. Experimental results obtained by ADV measurements provide mean velocity distributions and turbulence characteristics. The flow is sh...

Cassan, Ludovic; Belaud, Gilles

2012-01-01

326

Experimental investigation of the cyclic behaviour of unreinforced masonry spandrels  

OpenAIRE

In unreinforced masonry (URM) walls the vertical piers are connected by horizontal spandrel elements. Numerical simulations have shown that spandrels influence significantly the global wall behaviour under seismic loading. Despite their importance, experimental data on the cyclic behaviour of these spandrels is very scarce. The lack of experimental data prevented in the past the validation of numerical and mechanical models regarding the cyclic behaviour of masonry spandrels. For this reason ...

Beyer, Katrin; Abo El Ezz, Ahmad; Dazio, Alessandro

2010-01-01

327

Seismic and geologic investigations of the Sandia Livermore Laboratory site and structural investigations of the Tritium Research Facility  

Energy Technology Data Exchange (ETDEWEB)

This report consists of two parts. Part I, Seismic and Geologic Investigations of the Sandia Livermore Laboratory Site, covers the review and investigation of existing data as well as the acquisition and analysis of new data from field explorations and field examinations of the site. Part II, Structural Investigations of the Tritium Research Facility, covers: (a) the structural evaluation of the existing buildings and vital systems of the facility, and (b) concept studies of various schemes to strengthen the buildings and systems. Separate abstracts were prepared for each part.

1978-09-01

328

Experimental investigation of role of steam in entrained flow coal gasification  

Energy Technology Data Exchange (ETDEWEB)

Experimental investigations of the influence of excess oxygen coefficient, H{sub 2}O/coal mass ratio using high-temperature steam, mean mass diameter of pulverized coal and coal size fraction on basic characteristics of coal gasification were performed. Experiments were carried out on a laboratory scale (0.09 m i.d. x 1.5 m high) coal gasification apparatus with lignite type of coal. Influence of steam was realized through comparison of results obtained from experiments with (H{sub 2}O/coal = 0.287 kg kg{sup -1}) and without steam addition (H{sub 2}O/coal = 0.024 kg kg{sup -1}). High values of carbon conversion, obtained both for finely ground and for coarse pulverized coal points to the easiness of lignite gasification, i.e. to its high suitability for gasification. 14 refs., 6 figs., 5 tabs.

Nenad Crnomarkovic; Branislav Repic; Rastko Mladenovic; Olivera Neskovic; Miomir Veljkovic [Institute of Nuclear Sciences - Vinca, Belgrade (Serbia and Montenegro). Laboratory for Thermal Engineering and Energy

2007-01-15

329

A theoretical and experimental investigation of cylindrical electrostatic probes at arbitrary incidence in flowing plasma  

Science.gov (United States)

The theory for calculating the current collected by a negatively biased cylindrical electrostatic probe at an arbitrary angle of attack in a weakley ionized flowing plasma is presented. The theory was constructed by considering both random and directed motion simultaneous with dynamic coupling of the flow properties and of the electric field of the probe. This direct approach yielded a theory that is more general than static plasma theories modified to account for flow. Theoretical calculations are compared with experimental electrostatic probe data obtained in the free stream of an arc-heated hypersonic wind tunnel. The theoretical calculations are based on flow conditions and plasma electron densities measured by an independent microwave interferometer technique. In addition, the theory is compared with laboratory and satellite data previously published by other investigators. In each case the comparison gives good agreement.

Jenkins, R. V.; Jones, W. L., Jr.

1974-01-01

330

Theoretical and experimental investigation of cylindrical electrostatic probes at arbitrary incidence in flowing plasma  

International Nuclear Information System (INIS)

The theory for calculating the current collected by a negatively biased cylindrical electrostatic probe at an arbitrary angle of attack in a weakly ionized flowing plasma is presented. The theory was constructed by considering both random and directed motion simultaneous with dynamic coupling of the flow properties and of the electric field of the probe. This direct approach yielded a theory that is more general than static plasma theories modified to account for flow. Theoretical calculations are compared with experimental electrostatic probe data obtained in the free stream of an arc-heated hypersonic wind tunnel. The theoretical calculations are based on flow conditions and plasma electron densities measured by an independent microwave interferometer technique. In addition, the theory is compared with laboratory and satellite data previously published by other investigators. In each case the comparison gives good agreement. (auth)

331

The driver vigilance telemetric control system (DVTCS): investigating sensitivity to experimentally induced sleep loss and fatigue.  

Science.gov (United States)

Vigilance technologies are used in the Australian rail industry to address the risks associated with driver sleepiness and fatigue. The aim of this study was to investigate whether a new device, designed to detect lowered states of arousal using electrodermal activity (EDA), would be sensitive to experimentally induced sleepiness and fatigue. Fifteen individuals (7 of them female, 9 male; 18-32 years of age) spent 3 consecutive days in the laboratory, which included 1 night of sustained wakefulness (28 h). The participants completed a 10-min psychomotor vigilance task (PVT) and fatigue and sleepiness ratings every 2 h, and a 30-min driving simulator every 4 h. As was expected, simulated driving, PVT, and subjective ratings indicated increasing levels of sleepiness and fatigue during sustained wakefulness. The EDA device output did not coincide with these findings. The results indicated that the EDA indicator was not sensitive to increased sleepiness and fatigue at the levels produced in the present study. PMID:19001392

Dorrian, Jillian; Lamond, Nicole; Kozuchowski, Karolina; Dawson, Drew

2008-11-01

332

Testing geochemical models of bentonite pore water evolution against laboratory experimental data  

International Nuclear Information System (INIS)

The determination of a bentonite pore water composition and understanding its evolution with time underpins many radioactive waste disposal issues, such as buffer erosion, canister corrosion, and radionuclide solubility, sorption, and diffusion, inter alia. Previous modelling approaches have tended to ignore clay dissolution-precipitation reactions, a consequence of which is that montmorillonite is theoretically preserved indefinitely in the repository system. Here, we investigate the applicability of an alternative clay pore fluid evolution model, that incorporates clay dissolution-precipitation reactions as an integral component and test it against well-characterised laboratory experimental data, where key geochemical parameters, Eh and pH, have been measured directly in compacted bentonite. Simulations have been conducted using different computer codes (Geo-chemist's Workbench, PHREEQC, and QPAC) to test the applicability of this model. Thermodynamic data for the Gibb's free energy of formation of MX-80 smectite used in the calculations were estimated using two different methods ('Polymer' and 'Vieillard' Models).Simulations of 'end-point' pH measurements in batch bentonite-water slurry experiments showed different pH values according to the complexity of the system studied. The most complete system investigated revealed pH values were a strong function of partial pressure of carbon dioxide, with pH increasing with decreasing PCO2 (with log PCO22 (with log PCO2 values ranging from -3.5 to -7.5 bars produced pH values ranging from 7.9 to 9.6). A second set of calculations investigated disequilibrium between clay and pore fluid in laboratory squeezing cell tests involving pure water (pH = 9.0) or a 1 M NaOH solution (pH = 12.1). Simulations carried out for 100 days (the same timescale as the experiments) showed that smectite remained far from equilibrium throughout, and that the lowering of pH due to smectite hydrolysis was trivial. However, extending the duration of the simulations to that required for clay-fluid equilibrium, necessitated timescales of 7 and 65. years for pure water and 1 M NaOH, respectively, but again produced relatively minor reduction in pH (in the order of 0.1-0.2 pH units). If the (equilibrium) precipitation of secondary minerals was included in the simulations, then not only was the clay-fluid equilibration period extended dramatically (from 7 to 360 years for pure water, and from 65 to 2600. years for 1 M NaOH), but concomitant changes in pH were significant, decreasing from 9.0 to 8.6 (pure water) and from 12.1 to 9.0 (1 M NaOH). Repetition of these latter calculations using an alternative method for ?Gf0 smectite produced an increase in equilibration time for reaction with 1 M NaOH from 2600 to 5000 years, highlighting the potential effects of the uncertainty in thermodynamic data for smectite. A final set of calculations was carried out to investigate both the time- and space-dependent variations in pore fluid composition in laboratory in-diffusion experiments conducted for over 1200 days, initially with pure water and 'spiked' after 271 days with a Na-Ca-OH-Cl solution (pH = 11.7). Here, the sensitivity of the results to both variations in a number of parameters/conditions (porosity, reaction rate of secondary minerals, the degree of mixing of the external fluid reservoirs in the experiments, the effective diffusion coefficient) and the inclusion/exclusion of key processes (clay hydrolysis, secondary mineral precipitation, ion exchange, clay edge protonation-deprotonation reactions) was investigated. These calculations confirmed that smectite dissolution-precipitation reactions alone have an insignificant impact upon pH buffering over laboratory timescales and that the pH buffering observed is most likely controlled by clay protonation-deprotonation reactions, and kinetic secondary mineral (brucite + tobermorite) precipitation. Ion exchange reactions were found to have little effect on pH. Alternative data for the kinetic dissolution of smectite produced no observable differences, and the

333

An Experimental Investigation of the Scaling of Columnar Joints  

OpenAIRE

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

334

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

335

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

336

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

337

Experimental investigation of thermodynamics and fluid flow dynamics of district heating nuclear power stations at the experimental loop DANTON  

International Nuclear Information System (INIS)

Within the scope of engineering and scientific preparation of district heating nuclear power station application in the GDR, apart from theoretical investigations experimental studies on the performance of such plants are also being carried out. The experimental plant erected for this purpose at the Dresden Technical University is described. Objective and substance of the studies on the thermodynamics and fluid dynamics are outlined. (author)

338

Precise experimental investigation of eigenmodes in a planar ion crystal  

CERN Document Server

The accurate characterization of eigenmodes and eigenfrequencies of two-dimensional ion crystals provides the foundation for the use of such structures for quantum simulation purposes. We present a combined experimental and theoretical study of two-dimensional ion crystals. We demonstrate that standard pseudo-potential theory accurately predicts the positions of the ions and the location of structural transitions between different crystal configurations. However, pseudo-potential theory is insufficient to determine eigenfrequencies of the two-dimensional ion crystals accurately but shows significant deviations from the experimental data obtained from resolved sideband spectroscopy. Agreement at the level of 2.5 x 10^(-3) is found with the full time-dependent Coulomb theory using the Floquet-Lyapunov approach and the effect is understood from the dynamics of two-dimensional ion crystals in the Paul trap.

Kaufmann, H; Jacob, G; Poschinger, U; Landa, H; Retzker, A; Plenio, M B; Schmidt-Kaler, F

2012-01-01

339

Numerical and Experimental Investigation of Circulation in Short Cylinders  

CERN Document Server

In preparation for an experimental study of magnetorotational instability (MRI) in liquid metal, we explore Couette flows having height comparable to the gap between cylinders, centrifugally stable rotation, and high Reynolds number. Experiments in water are compared with numerical simulations. Simulations show that endcaps corotating with the outer cylinder drive a strong poloidal circulation that redistributes angular momentum. Predicted azimuthal flow profiles agree well with experimental measurements. Spin-down times scale with Reynolds number as expected for laminar Ekman circulation; extrapolation from two-dimensional simulations at $Re\\le 3200$ agrees remarkably well with experiment at $Re\\sim 10^6$. This suggests that turbulence does not dominate the effective viscosity. Further detailed numerical studies reveal a strong radially inward flow near both endcaps. After turning vertically along the inner cylinder, these flows converge at the midplane and depart the boundary in a radial jet. To minimize th...

Kageyama, A; Goodman, J; Chen, F; Shoshan, E; Kageyama, Akira; Ji, Hantao; Goodman, Jeremy; Chen, Fei; Shoshan, Ethan

2004-01-01

340

Experimental investigation and modeling of scale effects in jet ejectors  

Science.gov (United States)

Three microscale jet ejectors were designed and tested to induce a suction draft using a supersonic micronozzle. Each axisymmetric nozzle was fabricated using three-dimensional electro-discharge machining to create throat diameters of 64, 187 and 733 µm with design expansion ratios of 2.5:1 and design ejector area ratios of 8. The experimental data using nitrogen gas for the motive fluid indicate that the ejector can produce a sufficient suction draft to enable its substitution for high-speed turbomachinery in micro engine applications. A pumping power density of 308 kW L-1 is observed experimentally, which agrees well with a theoretical model including losses associated with the suction flow inlet and viscous effects in the motive nozzle and mixing regions. The present theoretical model further predicts a maximum achievable power density of 1 MW L-1 for microscale ejectors with a throat diameter of 10 µm and throat Reynolds number of 1300.

Gardner, W. G.; Wang, I.; Jaworski, J. W.; Brikner, N. A.; Protz, J. M.

2010-08-01

341

Experimental investigation of radiative thermal rectifier using vanadium dioxide  

Science.gov (United States)

Vanadium dioxide (VO2) exhibits a phase-change behavior from the insulating state to the metallic state around 340 K. By using this effect, we experimentally demonstrate a radiative thermal rectifier in the far-field regime with a thin film VO2 deposited on the silicon wafer. A rectification contrast ratio as large as two is accurately obtained by utilizing a one-dimensional steady-state heat flux measurement system. We develop a theoretical model of the thermal rectifier with optical responses of the materials retrieved from the measured mid-infrared reflection spectra, which is cross-checked with experimentally measured heat flux. Furthermore, we tune the operating temperatures by doping the VO2 film with tungsten (W). These results open up prospects in the fields of thermal management and thermal information processing.

Ito, Kota; Nishikawa, Kazutaka; Iizuka, Hideo; Toshiyoshi, Hiroshi

2014-12-01

342

Experimental and analytical investigation of a PWR natural circulation loop  

International Nuclear Information System (INIS)

A theoretical and experimental study of a natural circulation loop relevant to PWRs is presented. The analysis is based on a one-dimensional model in which the continuity momentum and energy equations are given and solved. The steady-state and transient flow rates and temperatures are derived. The apparatus consisted of an electrically-heated section and two parallel loops with heat exchangers. Both steady-state and transient experiments were conducted to study the effects of the core flow resistance, the power distribution, and the upper plenum design. Flow oscillations were observed under certain conditions, which were accompained by instabilities and flow reversals. Reasonable agreement (+-30%) is obtained between the analytical and experimental results and with available plant data

343

Experimental investigation of the Debye-Waller factor in hydrogen and deuterium scattering from Cu[111] monocrystalline surfaces  

International Nuclear Information System (INIS)

Starting from the usual mathematical expression for Debye-Waller factor, the surface temperature and momentum transfer dependence of the specular scattering peak intensity, considered as a measure of the elastic part of the interaction process, has been experimentally investigated. In a small molecular beam scattering system, designed and built in our laboratories, hydrogen and deuterium beam scattering experiments from Cu[111] single-crystal surface has been carried out. General considerations about our experimental setup has been made in paper. The experiments for different surface temperatures and different incident angles for hydrogen and deuterium incident beams has been carried out. According to the experimental results, the surface temperature dependence of the specular peak intensity has been plotted and considered as a first base of discussion for our investigation. The deviation from the surface temperature linear dependence of the ln Isp for these angular distributions, in the 120-400 K range has been numerically evaluated, both for hydrogen and deuterium beams. (authors)

344

Investigations in Experimental and Theoretical High Energy Physics  

Energy Technology Data Exchange (ETDEWEB)

We report on the work done under DOE grant DE-FG02-01ER41155. The experimental tasks have ongoing efforts at CERN (ATLAS), the Whipple observatory (VERITAS) and R&D work on dual readout calorimetry and neutrino-less double beta decay. The theoretical task emphasizes the weak interaction and in particular CP violation and neutrino physics. The detailed descriptions of the final report on each project are given under the appropriate task section of this report.

Krennrich, Frank [Iowa State University

2013-07-29

345

Experimental and numerical investigation of an axisymmetric supersonic jet  

OpenAIRE

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

346

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

347

Experimental investigation of unstrained diffusion flames and their instabilities  

OpenAIRE

In this thesis, thermal-diffusive instabilities are studied experimentally in diffusion flames. The novel species injector of a recently developed research burner, consisting of an array of hypodermic needles, which allows to produce quasi one-dimensional unstrained diffusion flames has been improved. It is used in a new symmetric design with fuel and oxidizer injected through needle arrays which allows to independently choose both the magnitude and direction of the bulk flow through the flam...

Robert, Etienne

2009-01-01

348

Theoretical and experimental investigations on incompressible flow through labyrinths  

International Nuclear Information System (INIS)

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 expectedoefficients for this profile were expectedly and experimentally proved to be higher resulting in its appreciably better performance than the square labyrinth profile

349

Theoretical and experimental investigation of thermohydrologic processes in a partially saturated, fractured porous medium  

Energy Technology Data Exchange (ETDEWEB)

The performance of a geologic repository for high-level nuclear waste will be influenced to a large degree by thermohydrologic phenomena created by the emplacement of heat-generating radioactive waste. The importance of these phenomena is manifest in that they can greatly affect the movement of moisture and the resulting transport of radionuclides from the repository. Thus, these phenomena must be well understood prior to a definitive assessment of a potential repository site. An investigation has been undertaken along three separate avenues of analysis: (i) laboratory experiments, (ii) mathematical models, and (iii) similitude analysis. A summary of accomplishments to date is as follows. (1) A review of the literature on the theory of heat and mass transfer in partially saturated porous medium. (2) A development of the governing conservation and constitutive equations. (3) A development of a dimensionless form of the governing equations. (4) A numerical study of the importance and sensitivity of flow to a set of dimensionless groups. (5) A survey and evaluation of experimental measurement techniques. (6) Execution of laboratory experiments of nonisothermal flow in a porous medium with a simulated fracture.

Green, R.T.; Manteufel, R.D. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Regulatory Applications; Dodge, F.T.; Svedeman, S.J. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

1993-07-01

350

Theoretical and experimental investigation of thermohydrologic processes in a partially saturated, fractured porous medium  

International Nuclear Information System (INIS)

The performance of a geologic repository for high-level nuclear waste will be influenced to a large degree by thermohydrologic phenomena created by the emplacement of heat-generating radioactive waste. The importance of these phenomena is manifest in that they can greatly affect the movement of moisture and the resulting transport of radionuclides from the repository. Thus, these phenomena must be well understood prior to a definitive assessment of a potential repository site. An investigation has been undertaken along three separate avenues of analysis: (i) laboratory experiments, (ii) mathematical models, and (iii) similitude analysis. A summary of accomplishments to date is as follows. (1) A review of the literature on the theory of heat and mass transfer in partially saturated porous medium. (2) A development of the governing conservation and constitutive equations. (3) A development of a dimensionless form of the governing equations. (4) A numerical study of the importance and sensitivity of flow to a set of dimensionless groups. (5) A survey and evaluation of experimental measurement techniques. (6) Execution of laboratory experiments of nonisothermal flow in a porous medium with a simulated fracture

351

Experimental program to investigate transonic flow around protuberances  

Science.gov (United States)

Transient and steady state aerodynamic flow of turbulent boundary layers are investigated for generalized cylindrical projections and several specific configurations used on the Saturn 5 launch vehicle. A transonic wind tunnel gave generalized information.

Robertson, J. E.

1969-01-01

352

Experimental and numerical investigation of hydro power generator ventilation  

Science.gov (United States)

Improvements in ventilation and cooling offer means to run hydro power generators at higher power output and at varying operating conditions. The electromagnetic, frictional and windage losses generate heat. The heat is removed by an air flow that is driven by fans and/or the rotor itself. The air flow goes through ventilation channels in the stator, to limit the electrical insulation temperatures. The temperature should be kept limited and uniform in both time and space, avoiding thermal stresses and hot-spots. For that purpose it is important that the flow of cooling air is distributed uniformly, and that flow separation and recirculation are minimized. Improvements of the air flow properties also lead to an improvement of the overall efficiency of the machine. A significant part of the windage losses occurs at the entrance of the stator ventilation channels, where the air flow turns abruptly from tangential to radial. The present work focuses exclusively on the air flow inside a generator model, and in particular on the flow inside the stator channels. The generator model design of the present work is based on a real generator that was previously studied. The model is manufactured taking into consideration the needs of both the experimental and numerical methodologies. Computational Fluid Dynamics (CFD) results have been used in the process of designing the experimental setup. The rotor and stator are manufactured using rapid-prototyping and plexi-glass, yielding a high geometrical accuracy, and optical experimental access. A special inlet section is designed for accurate air flow rate and inlet velocity profile measurements. The experimental measurements include Particle Image Velocimetry (PIV) and total pressure measurements inside the generator. The CFD simulations are performed based on the OpenFOAM CFD toolbox, and the steady-state frozen rotor approach. Specific studies are performed, on the effect of adding "pick-up" to spacers, and the effects of the inlet fan blades on the flow rate through the model. The CFD results capture the experimental flow details to a reasonable level of accuracy.

Jamshidi, H.; Nilsson, H.; Chernoray, V.

2014-12-01

353

Numerical and experimental investigation of a counter flow cooling system for the blown film extrusion  

Science.gov (United States)

Conventional cooling systems for the blown film extrusion govern the cooling airflow only in one direction. In contrast, a counter flow system uses two individual jet flows. One jet flow provides the air in draw up direction like used in conventional systems. The other one guides the airflow towards the die. It is possible to cool the film over a longer film surface intensively. In addition, the interaction of the jet flow and the ambient air can be reduced which is responsible for an unsteady heat transfer. In this paper, such a cooling system is investigated in detail, numerically as well as experimentally. The experimental work is done using a modular system for a laboratory blown film line. For the simulation, a process model is used which is able to compute a realistic blown film behavior depending on the actual cooling condition. Therefore, a CFD-analysis computes the temperature of the film and flow phenomena of the jets. A contour calculation model is used to predict the bubble shape. It is based on the framework from Pearson and Petrie and a modified Phan-Thien Tanner model for the rheological description of the tube formation zone. Both modules interact in a loop until a final quasi-stationary blown film contour is found. The aim of this investigation is to get a better understanding of the film cooling using a counter flow system for several different process states. In addition, this knowledge base can help to develop novel cooling approaches. Therefore, a process space is analyzed using a LDPE. To verify the simulation with the experimental results the film contour and frost line are measured.

Janas, M.; Fehlberg, L.; Wortberg, J.

2014-05-01

354

A novel experimental procedure to investigate the biodegradation of NAPL under unsaturated conditions  

Science.gov (United States)

SummarySoils need to be thoroughly investigated regarding their potential for the natural attenuation of non-aqueous phase liquids (NAPL). Laboratory investigations truly representative of degradation processes in field conditions are difficult to implement for porous media partially saturated with water, NAPL and air. We propose an innovative protocol to investigate degradation processes under steady-state vadose zone conditions. Experiments are carried out in glass columns filled with a sand and, as bacteria source, a soil from a diesel-fuel-polluted site. Water and NAPL ( n-hexadecane diluted in heptamethylnonane (HMN)) are added to the porous medium in a two-step procedure using ceramic membranes placed at the bottom of the column. This procedure results, for appropriate experimental conditions, in a uniform distribution of the two fluids (water and NAPL) throughout the column. In a biodegradation experiment non-biodegradable HMN is used to provide NAPL mass, while keeping biodegradable n-hexadecane small enough to monitor its rapid degradation. Biodegradation is followed as a function of time by measuring oxygen consumption, using a respirometer. Degradative activity is controlled by diffusive transfers in the porous network, of oxygen from the gas phase to the water phase and of n-hexadecane from the NAPL phase to the water phase.

Andre, Laurent; Kedziorek, Monika A. M.; Bourg, Alain C. M.; Haeseler, Frank; Blanchet, Denis

2009-05-01

355

Electromagnetic Investigations and Power Converter Efficiency Studies on a Laboratory Made Induction Heating Prototype  

Science.gov (United States)

In this paper electromagnetic analysis and power converter efficiency has been studied on a laboratory prototype induction heating coil. An electromagnetic field based study was first done for the induction heating coil used in the experimental set-up using available Finite Element Analysis package software (FEMM 4.2). The results of the FEM based study are also used in the choice of the operating frequency depending on the applications. Thereafter verifications are done experimentally on a small-scale laboratory developed setup. The approach to be adopted for choice of induction heating operating frequency and the choice of converter type, based on the efficiency and performance, are also briefly presented here. Oscilloscope traces uphold the accuracy of the practical tests conducted.

Roy, M.; Sengupta, M.

2013-09-01

356

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)

357

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

358

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

OpenAIRE

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...

Horvat, M.; Kocman, D.

2010-01-01

359

Numerical and experimental investigation of thermal louvers for space applications  

Directory of Open Access Journals (Sweden)

Full Text Available 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 spacecraft thermal louver show good agreement with the theoretical values.

Muraoka Issamu

2001-01-01

360

Experimental Investigation of Tesla Turbine and its Underlying Theory  

OpenAIRE

Nikola Tesla is widely known for his outstanding achievements in generation transmission and utilization of power. The object of this paper is to experimentally verify one such method of extracting electrical power from fluid energy; devised by Tesla in his 1913 patent; known as Tesla Turbine. It is to be noted that almost no work has been done using water as the working fluid for the turbine so an attempt to reconstruct the turbine as per Nikola Tesla’s patent has been made with positive r...

Kartikeya Awasthi; Aman Aggarwal

2014-01-01

361

Experimental investigation of magnetic anisotropy in spin vortex discs  

International Nuclear Information System (INIS)

We present experimental 2D vector vibrating sample magnetometer measurements to demonstrate the shape anisotropy effects occurring in micrometer-diameter supermalloy spin vortex discs. Measurements made for different disc sizes and orientations confirm the out-of-plane susceptibility is several orders of magnitude smaller than the in-plane susceptibility. These results validate with a high certitude that spin vortices with high diameter to thickness ratio retain in-plane-only magnetization, even when subjected to fields in the out-of-plane direction. These results contribute to further computational simulations of the dynamics of spin vortex structures in colloidal suspensions where external fields may be applied in any arbitrary direction

362

Experimental investigation of magnetic anisotropy in spin vortex discs  

Energy Technology Data Exchange (ETDEWEB)

We present experimental 2D vector vibrating sample magnetometer measurements to demonstrate the shape anisotropy effects occurring in micrometer-diameter supermalloy spin vortex discs. Measurements made for different disc sizes and orientations confirm the out-of-plane susceptibility is several orders of magnitude smaller than the in-plane susceptibility. These results validate with a high certitude that spin vortices with high diameter to thickness ratio retain in-plane-only magnetization, even when subjected to fields in the out-of-plane direction. These results contribute to further computational simulations of the dynamics of spin vortex structures in colloidal suspensions where external fields may be applied in any arbitrary direction.

Garraud, N., E-mail: ngarraud@ufl.edu; Arnold, D. P. [Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida 32611 (United States)

2014-05-07

363

Numerical and experimental investigation of thermal louvers for space applications  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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 spacecraft thermal louver show good agreement with the theoretical values.

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

364

The experimental investigation of bounce characteristics of ACV responsive skirt  

Science.gov (United States)

This paper presents some experimental results on the bounce characteristics of the bag-finger responsive skirt and on skirt frequency response under cushion pressure excitation obtained in a large-scale box facility. The influence of some parameters on the amplitude and frequency of the skirt bounce motion and the amplitude of the cushion pressure oscillation were explored, and the corresponding bounce boundary curves are given. Some interesting nonlinear phenomena related to the skirt instability in the time domain response are presented. The mechanism for skirt bounce and the important parameters affecting skirt dynamic stability are examined, and some means for eliminating skirt bounce are introduced.

Zhou, W. L.; Ma, T.

365

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)

366

Experimental investigations on the four-loop test facility ROCOM  

International Nuclear Information System (INIS)

For the analysis of the core behaviour during boron dilution transients and main steam line breaks, coupled neutron kinetic/thermal hydraulic codes are necessary. These codes must contain models of the coolant mixing on its way from the inlet nozzles to the core entrance, because the reactivity insertion strongly depends on the distribution of temperature and boron concentration at the core inlet. To model the coolant mixing the ROCOM test facility was built, a fluid dynamic 1:5 scaled model of the Konvoi reactor. The experimental results at steady state flow conditions are presented in a survey form. (orig.)

367

Experimental investigation of engine jet/vortex interaction  

OpenAIRE

Since the 1970s a main topic in vortex research is the problem of wake vortex hazard. This thesis focuses on the aspect of engine jet vortex interaction and discusses experimental results from low speed wind tunnel tests in the wake of a swept wing half model with a model engine that can be span wise moved during wind tunnel operation. The falsifying effect of vortex meandering or unsteady movement on the evaluation of wake vortex measurements using PIV technique is analysed by a numerical me...

Huppertz, G.

2010-01-01

368

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

369

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)

370

Facilities for post-irradiation examination of experimental fuel elements at Chalk River Nuclear Laboratories  

International Nuclear Information System (INIS)

Expansion of post-irradiation facilities at the Chalk River Nuclear Laboratories and steady improvement in hot-cell techniques and equipment are providing more support to Canada's reactor fuel development program. The hot-cell facility primarily used for examination of experimental fuels averages a quarterly throughput of 40 elements and 110 metallographic specimens. New developments in ultrasonic testing, metallographic sample preparation, active storage, active waste filtration, and fissile accountability are coming into use to increase the efficiency and safety of hot-cell operations. (author)

371

Experimental and in situ investigations on americium, curium and plutonium behaviour in marine benthic species: transfer from water or sediments  

International Nuclear Information System (INIS)

The tranfer of transuranic elements -americium, curium and plutonium- from the sediments containing them to some marine benthic species (endofauna and epifauna) was studied with a twofold approach - laboratory and in-situ investigation. The experimental investigations, divided into three parts, made it possible to specify concentration factors (F.C.), transfer factors (F.T.) and to understand the process involved for 5 benthic species. The result were refined by an in-situ study that brought new data on the marine distribution of the transuranic elements released by the La Hague plant. Finally, the localization of americium and plutonium in the tissues and cells of these species was determined by autoradiography

372

Experimental Investigations of Ice Rubble: Shear Box and Pile Testing  

OpenAIRE

The largest part of an ice ridge consists of unconsolidated ice rubble, whose material properties decide the load from ridges on ships and structures. Material resistance is attributed to the initial freeze-bonds and the friction and interlocking between blocks. The objective of the thesis was to investigate rubble behaviour by two tests: shear box test at NTNU and pile test at HSVA. The shear box test was aimed at investigating freeze-bond mechanisms in rubble. The pile test was aimed at sug...

Astrup, Oda Skog

2012-01-01

373

Experimental and numerical investigation of flameless pulverised coal combustion  

OpenAIRE

Aim of this work was to investigate the applicability of flameless combustion technology principles to pulverised coal combustion. Lab-scale experiments showed, that it is highly beneficial in terms of NOx reduction to use N2 as coal carrier instead of air. The finding has been supported by OH* chemiluminescence imaging which revealed a suppression of ignition in the coal jet when N2 is used. With the investigated settings, NOx emissions are always above the legislative limit of 200 mg/m3 (st...

Stadler, Hannes Alexander

2010-01-01

374

Incipient Transient Detection in Reactor Systems: Experimental and Theoretical Investigation  

Energy Technology Data Exchange (ETDEWEB)

The main goal of this research was to develop a method for detecting reactor system transients at the earliest possible time through a comprehensive experimental, testing and benchmarking program. This approach holds strong promise for developing new diagnostic technologies that are non-intrusive, generic and highly portable across different systems. It will help in the design of new generation nuclear power reactors, which utilize passive safety systems with a reliable and non-intrusive multiphase flow diagnostic system to monitor the function of the passive safety systems. The main objective of this research was to develop an improved fuzzy logic based detection method based on a comprehensive experimental testing program to detect reactor transients at the earliest possible time, practically at their birth moment. A fuzzy logic and neural network based transient identification methodology and implemented in a computer code called PROTREN was considered in this research and was compared with SPRT (Sequentially Probability Ratio Testing) decision and Bayesian inference. The project involved experiment, theoretical modeling and a thermal-hydraulic code assessment. It involved graduate and undergraduate students participation providing them with exposure and training in advanced reactor concepts and safety systems. In this final report, main tasks performed during the project period are summarized and the selected results are presented. Detailed descriptions for the tasks and the results are presented in previous yearly reports (Revankar et al 2003 and Revankar et al 2004).

Lefteri H. Tsoukalas; S.T. Revankar; X Wang; R. Sattuluri

2005-09-27

375

Experimental investigation two phase flow in direct methanol fuel cells  

International Nuclear Information System (INIS)

Direct methanol fuel cells (DMFC) have received many attentions specifically for portable electronic applications since it utilize methanol which is in liquid form in atmospheric condition and high energy density of the methanol. Thus it eliminates the storage problem of hydrogen. It also eliminates humidification requirement of polymeric membrane which is a problem in PEM fuel cells. Some electronic companies introduced DMFC prototypes for portable electronic applications. Presence of carbon dioxide gases due to electrochemical reactions in anode makes the problem a two phase problem. A two phase flow may occur at cathode specifically at high current densities due to the excess water. Presence of gas phase in anode region and liquid phase in cathode region prevents diffusion of fuel and oxygen to the reaction sites thus reduces the performance of the system. Uncontrolled pressure buildup in anode region increases methanol crossover through membrane and adversely effect the performance. Two phase flow in both anode and cathode region is very effective in the performance of DMYC system and a detailed understanding of two phase flow for high performance DMFC systems. Although there are many theoretical and experimental studies available on the DMFC systems in the literature, only few studies consider problem as a two-phase flow problem. In this study, an experimental set up is developed and species distributions on system are measured with a gas chromatograph. System performance characteristics (V-I curves) is measured depending on the process parameters (temperature, fuel ad oxidant flow rates, methanol concentration etc)

376

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

377

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

378

Experimental investigation of thermal emittance components of copper photocathode  

Science.gov (United States)

With progress of photoinjector technology, thermal emittance has become the primary limitation of electron beam brightness. Extensive efforts have been devoted to study thermal emittance, but experiment results differ between research groups and few can be well interpreted. Besides the ambiguity of photoemission mechanism, variations of cathode surface conditions during cathode preparation, such as work function, field enhancement factor, and surface roughness, will cause thermal emittance differences. In this paper, we report an experimental study of electric field dependence of copper cathode quantum efficiency (QE) and thermal emittance in a radio frequency (rf) gun, through which in situ cathode surface parameters and thermal emittance contributions from photon energy, Schottky effect, and surface roughness are extracted. It is found the QE of a copper cathode illuminated by a 266 nm UV laser increased substantially to 1.5×10-4 after cathode cleaning during rf conditioning, and a copper work function of 4.16 eV, which is much lower than nominal value (4.65 eV), was measured. Experimental results also show a thermal emittance growth as much as 0.92mmmrad/mm at 50MV/m due to the cathode surface roughness effect, which is consistent with cathode surface morphology measurements.

Qian, H. J.; Li, C.; Du, Y. C.; Yan, L. X.; Hua, J. F.; Huang, W. H.; Tang, C. X.

2012-04-01

379

Control strategies for friction dampers: numerical assessment and experimental investigations.  

Directory of Open Access Journals (Sweden)

Full Text Available The use of friction dampers has been proposed in a wide variety of mechanical systems for which it is not possible to apply viscoelastic materials, fluid based dampers or others viscous dampers. An important example is the application of friction dampers in aircraft engines to reduce the blades vibration amplitudes. In most cases, friction dampers have been studied in a passive way, however, a significant improvement can be achieved by controlling the normal force in the dampers. The aim of this paper is to study three control strategies for friction dampers based on the hysteresis cycle. The first control strategy maximizes the energy removal in each harmonic oscillation cycle, by calculating the optimum normal force based on the last displacement peak. The second control strategy combines the first one with the maximum energy removal strategy used in the smart spring devices. Finally, is presented the strategy which homogenously modulates the friction force. Numerical studies were performed with these three strategies defining the performance metrics. The best control strategy was applied experimentally. The experimental test rig was fully identified and its parameters were used for the numerical simulations. The obtained results show the good performance for the friction damper and the selected strategy.

Coelho H.T.

2014-01-01

380

Experimental investigation of a cavitating backward-facing step flow  

Science.gov (United States)

The present study is the first part of global experimental work which is intended to produce a refined database of liquid and vapor phases and to improve CFD modeling of turbulent cavitating flows which can occur in rocket engine turbo-pump inducers. The purpose of the present experimental study is to get a better understanding of the dynamics of the liquid phase in a cavitating backward facing step flow and provide a refined database for the physical analysis of interaction between turbulence and cavitation. The backward facing step flow provides us a well-known test case to compare vortex dynamics and a realistic industrial configuration such as backflow in turbo machinery. Experiments were conducted in the hydrodynamic tunnel of CREMHyG at Grenoble,which was especially designed to study cavitating shear flows at high Reynolds numbers. To highlight the liquid phase topology and dynamics such as large vortex structures, free shear layer instability, reattachment wall interaction and reverse flow, the flow is characterized by Laser Induced Fluoresence Particles Image Velocimetry (PIV-LIF) measurements techniques and by Laser Doppler Velocimetry (LDV) techniques using spectral analysis to characterize the vortex shedding dynamics. The liquid phase was analyzed at different cavitation levels corresponding to 1% to 45% of void ratio range inside the shear layer, recirculation area and reattachment zone. The mean and fluctuating liquid velocities are clearly modified by the vapor phase and the scale of the vortical structures tends to be smaller inducing a destructuration of turbulence by cavitation.

Maurice, G.; Djeridi, H.; Barre, S.

2014-12-01

381

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

382

Cloning Yeast Actin cDNA Leads to an Investigative Approach for the Molecular Biology Laboratory  

Science.gov (United States)

The emergence of molecular tools in multiple disciplines has elevated the importance of undergraduate laboratory courses that train students in molecular biology techniques. Although it would also be desirable to provide students with opportunities to apply these techniques in an investigative manner, this is generally not possible in the…

Black, Michael W.; Tuan, Alice; Jonasson, Erin

2008-01-01

383

Local and Remote Laboratory User Experimentation Access using Digital Programmable Logic  

Directory of Open Access Journals (Sweden)

Full Text Available This paper will discuss the structure and operation of a programmable logic based experimentation arrangement that is suitable for both local and remote teaching and learning scenarios targeting electronic and microelectronic circuit design and test principles. With this experimentation arrangement, the ability to provide both local and Internet based “remote” access for the student and the teacher can provide a number of advantages where physical laboratory accessibility is limited and/or the learning experience must be undertaken with one or more of the parties remotely based. The paper concentrates on the design and example use of a system developed within the University of Limerick.

Ian A Grout

2005-06-01

384

Experimental investigation of in situ cleanable HEPA filters  

International Nuclear Information System (INIS)

Savannah River Technology Center (SRTC), High Level Waste Division, Tanks Focus Area, and the Federal Energy Technology Center (FETC) have been investigating high efficiency particulate air (HEPA) filters which can be regenerated or cleaned in situ as an alternative to conventional disposable HEPA filters. This technical report documents concerns pertaining to conventional HEPA filters

385

Investigation of the fast neutron induced (n, ?) reaction. (Experimental techniques)  

International Nuclear Information System (INIS)

For investigation of the fast neutron induced (n, ?)-reaction, two grid-type gas-filled twin ionization chambers were developed and tested. Using the ionization chambers, the energy spectra, angular distributions and cross sections of the (n, ?)-reaction were measured around En=5 MeV for 40Ca, 58Ni and 64Zn. 27 refs., 20 figs., 1 tab

386

Experimental investigation of the reaction at REX-ISOLDE  

CERN Document Server

The particle unbound nucleus /sup 10/Li has been investigated at the newly constructed post-accelerator REX-ISOLDE at CERN via the /sup 9 /Li+d to /sup 10/Li+p reaction at 2.36 MeV/u. We present here the preliminary analysis of our first data from REX-ISOLDE.

Jeppesen, H B; Bergmann, U C; García-Borge, M J; Cederkäll, J; Emhofer, S; Fraile-Prieto, L M; Fynbo, H O U; Henry, S; Johansson, H T; Jonson, B; Meister, M; Nilsson, T; Nyman, G H; Pantea, M; Riisager, K; Richter, A; Rudolph, K; Schrieder, G; Siebert, T; Tengblad, O; Tengborn, E; Turrión, M; Von Hahn, R; Wenander, F; Wolf, B

2004-01-01

387

Experimental Investigations of Space Shuttle BX-265 Foam  

Science.gov (United States)

This report presents a variety of experimental studies on the polyurethane foam, BX-265. This foam is used as a close-out foam insulation on the space shuttle external tank. The purpose of this work is to provide a better understanding of the foam s behavior and to support advanced modeling efforts. The following experiments were performed: Thermal expansion was measured for various heating rates. The in situ expansion of foam cells was documented by heating the foam in a scanning electron microscope. Expansion mechanisms are described. Thermogravimetric analysis was performed at various heating rates and for various environments. The glass transition temperature was also measured. The effects of moisture on the foam were studied. Time-dependent effects were measured to give preliminary data on viscoelastoplastic properties.

Lerch, Bradley A.; Sullivan, Roy M.

2009-01-01

388

Experimental, quantum chemical and NBO/NLMO investigations of pantoprazole.  

Science.gov (United States)

The complete vibrational assignment and analysis of the fundamental modes of pantoprazole (PPZ) was carried out using the experimental FT-IR, FT-Raman and UV-Vis data and quantum chemical studies. The observed vibrational data were compared with the wavenumbers derived theoretically for the optimized geometry of the compound from the DFT-B3LYP gradient calculations employing 6-31G (d, p) basis set. Thermodynamic properties like entropy, heat capacity and enthalpy have been calculated for the molecule. HOMO-LUMO energy gap has been calculated. The intramolecular contacts have been interpreted using natural bond orbital (NBO) and natural localized molecular orbital (NLMO) analysis. Important non-linear properties such as electric dipole moment and first hyperpolarizability of PPZ have been computed using B3LYP quantum chemical calculation. Finally, the Mulliken population analysis on atomic charges of the title compound has been calculated. PMID:25315871

Rajesh, P; Gunasekaran, S; Gnanasambandan, T; Seshadri, S

2015-02-01

389

Experimental Investigation of Tesla Turbine and its Underlying Theory  

Directory of Open Access Journals (Sweden)

Full Text Available Nikola Tesla is widely known for his outstanding achievements in generation transmission and utilization of power. The object of this paper is to experimentally verify one such method of extracting electrical power from fluid energy; devised by Tesla in his 1913 patent; known as Tesla Turbine. It is to be noted that almost no work has been done using water as the working fluid for the turbine so an attempt to reconstruct the turbine as per Nikola Tesla’s patent has been made with positive results obtained by generation of useful electrical power using water as the medium which provides a new outlook towards our understanding of the turbines and the ways by which mechanical energy of the motive fluid can be converted into useful electrical output. .

Kartikeya Awasthi

2014-07-01

390

Experimental investigation of universal parametric correlators using a vibrating plate  

CERN Document Server

The parametric variation of the eigenfrequencies of a chaotic plate is measured and compared to random matrix theory using recently calculated universal correlation functions. The sensitivity of the flexural modes of the plate to pressure is used to isolate this symmetry class of modes and simplify the data analysis. The size of the plate is used as the external parameter and the eigenvalues are observed to undergo one or two oscillations in the experimental window. The correlations of the eigenvalues are in good agreement with statistical measures such as the parametric number variance, the velocity autocorrelation, and the intralevel velocity autocorrelation derived for the Gaussian Orthogonal Ensemble of random matrix theory. Our results show that the theory can be also applied to wave systems other than quantum systems.

Schaadt, K

1999-01-01

391

Experimental, quantum chemical and NBO/NLMO investigations of pantoprazole  

Science.gov (United States)

The complete vibrational assignment and analysis of the fundamental modes of pantoprazole (PPZ) was carried out using the experimental FT-IR, FT-Raman and UV-Vis data and quantum chemical studies. The observed vibrational data were compared with the wavenumbers derived theoretically for the optimized geometry of the compound from the DFT-B3LYP gradient calculations employing 6-31G (d, p) basis set. Thermodynamic properties like entropy, heat capacity and enthalpy have been calculated for the molecule. HOMO-LUMO energy gap has been calculated. The intramolecular contacts have been interpreted using natural bond orbital (NBO) and natural localized molecular orbital (NLMO) analysis. Important non-linear properties such as electric dipole moment and first hyperpolarizability of PPZ have been computed using B3LYP quantum chemical calculation. Finally, the Mulliken population analysis on atomic charges of the title compound has been calculated.

Rajesh, P.; Gunasekaran, S.; Gnanasambandan, T.; Seshadri, S.

2015-02-01

392

Aeroacoustics of T-junctions—An experimental investigation  

Science.gov (United States)

An experimental method for determining the aeroacoustic properties of side branch orifices allowing for any combination of grazing and bias flow is presented. The geometry studied, a T-junction, is treated as an active acoustic three-port. The passive properties, describing the reflection and transmission of an incident acoustic wave, are described by a system matrix while the active properties are described by a source vector. Expressions for the acoustic impedance under various mean flow and acoustic incidence configurations are developed. In addition, methods for identifying regions where the system can generate sound, by studying only the passive properties, are discussed. A self-sustained oscillation is triggered at one of the identified regions by coupling a resonant system to the three-port.

Karlsson, Mikael; Åbom, Mats

2010-05-01

393

Performance enhancement of solar module by cooling: An experimental investigation  

Directory of Open Access Journals (Sweden)

Full Text Available The study evaluates the silicone oil cooling of the solar module surface. Solar module with maximum power of 7W was employed for cooling. This paper summarizes the result of an outdoor experiment. The experiments were conducted in batch mode, with the cooling medium spread on the module surface at different thickness from 0mm to 6mm. The performance of the module, throughout the day, for different thickness of the medium is reported. The study also presents a mathematical model, predicting the variation of the maximum power when the module surface is cooled using silicone oil. The results of the equation model are compared and validated with the experimental as well as with results reported in the earlier works. The cooling contributes to appreciable improvement in the module efficiency to above 20%.

P G Nikhil, M Premalatha

2012-01-01

394

An experimental and analytical investigation of a threaded fastener  

Science.gov (United States)

The fatigue strength of a connecting rod consisting of a threaded bar and an integral lug end was analyzed both experimentally and analytically. Different geometries and manufacturing methods were considered. These included cut and rolled threads, lugs which were welded to the threaded bar or machined with the threads from a single piece of material, and rods both with and without a reduced section between the threads and lug end. Fatigue tensile tests showed the reduced section between lug and threads and sometimes the lug itself to be the weakest point of the component. The rods with a welded lug and a reduced section between threads and lug were found to have the highest fatigue strengths. Rolled threads showed higher fatigue strength than did cut threads at the endurance limit. All analytically determined fatigue limits were conservative compared to test results.

Sipilae, Sisko

1993-11-01

395

Experimental investigation of radiation damage in reactor pressure vessel steels  

International Nuclear Information System (INIS)

The results are summarized on experimental study of the effects of neutron dose, irradiation temperature, and chemical composition on radiation embrittlement of some steels of Czechoslovak and of foreign make designed for power reactor pressure vessels. The chemical composition of all tested steels is tabulated; irradiation proceeded on the WWR-S reactor. It was found that radiation embrittlement resistance of Czechoslovak made steels was similar to that of foreign steels. It was found that the life and thus also the safety of pressure vessels can be improved by improved production technology of steels, mainly by vacuum degassing prior to casting, by achieving the finest possible granularity, by the optimal choice of heat treatment parameters and of the content of some elements affecting the magnitude of radiation embrittlement of steels, such as carbon, nickel, and vanadium. (O.K.)

396

Experimental investigation to demonstrate Impact Fast Ignition scheme  

Science.gov (United States)

We have proposed a new ignition scheme of Fast Ignition, called "Impact Fast Ignition (IFI)", in which a compressed fuel is ignited by impact collision of a fragment of separately imploded fuel. We performed integrated experiments on impact ignition, in which a portion of a deuterated polystyrene (CD) shell was accelerated to about 600 km/s and was collided with precompressed CD fuel. The shell was imploded using 9 beams and the impactor was accelerated using 3 beams of the GEKKO XII laser system. The laser energy was 350 J per beam. The kinetic energy of the impactor was efficiently converted into thermal energy generating a temperature of about 1.8 keV., Observed maximum neutron yield was 2×106. This yield was 80 times as large as that without impactor. We will present the experimental details and results, demonstrating the high potential of impact ignition for fusion energy production.

Watari, T.; Azechi, H.; Nakai, M.; Hironaka, Y.; Sakaiya, T.; Nakamura, H.; Shiraga, H.; Shigemori, K.; Hosoda, H.; Arikawa, Y.; Homma, H.; Norimatsu, T.; Murakami, M.; Jhozaki, T.; TMS Group; GOD Group; Karasik, M.; Gardner, J.; Bates, J.; Colombant, D.; Weber, J.; Aglitsky, Y.; Obenschain, S.

2010-08-01

397

Experimental investigation of damping force of twin tube shock absorber  

Directory of Open Access Journals (Sweden)

Full Text Available A shock absorber is a mechanical device to damp shock impulse and convert kinetic energy into thermal energy. The damping effect of shock absorber depends on damping force and damping force is affected by various process parameters. In this analysis three process parameters damping diameter(A, number of holes(B and suspension velocity(C were considered and their effect on damping force of shock absorber was studied and accordingly suitable orthogonal array was selected by taguchi method. Experiment conducted on servo hydraulic testing machine and after conducting experiments damping force was measured and with the help of S/N ratio, ANOVA, Regression analysis optimum parameter values can be obtained and confirmation experiments was carried out. Twin tube shock absorber was used to carry out experimentation.

Sandip K. Kadu

2014-09-01

398

Experimental investigation of nanosecond discharge plasma aerodynamic actuation  

International Nuclear Information System (INIS)

In this paper we report on an experimental study of the characteristics of nanosecond pulsed discharge plasma aerodynamic actuation. The N2 (C3?u) rotational and vibrational temperatures are around 430 K and 0.24 eV, respectively. The emission intensity ratio between the first negative system and the second positive system of N2, as a rough indicator of the temporally and spatially averaged electron energy, has a minor dependence on applied voltage amplitude. The induced flow direction is not parallel, but vertical to the dielectric layer surface, as shown by measurements of body force, velocity, and vorticity. Nanosecond discharge plasma aerodynamic actuation is effective in airfoil flow separation control at freestream speeds up to 100 m/s. (physics of gases, plasmas, and electric discharges)

399

An experimental investigation of double beta decay of 100Mo  

International Nuclear Information System (INIS)

New limits on half-lives for several double beta decay modes of 100Mo were obtained with a novel experimental system which included thin source films interleaved with a coaxial array of windowless silicon detectors. Segmentation and timing information allowed backgrounds originating in the films to be studied in some detail. Dummy films containing 96Mo were used to assess remaining backgrounds. With 0.1 mole years of 100Mo data collected, the lower half-life limits at 90% confidence were 2.7 /times/ 1018 years for decay via the two-neutrino mode, 5.2 /times/1019 years for decay with the emission of a Majoron, and 1.6 /times/ 1020 years and 2.2 /times/ 1021 years for neutrinoless 0+ ? 2+ and 0+ ? 0+ transitions, respectively. 50 refs., 38 figs., 11 tabs

400

Experimental Investigation of Hypersonic Flow and Plasma Aerodynamic Actuation Interaction  

International Nuclear Information System (INIS)

For hypersonic flow, it was found that the most effective plasma actuator is derived from an electromagnetic perturbation. An experimental study was performed between hypersonic flow and plasma aerodynamic actuation interaction in a hypersonic shock tunnel, in which a Mach number of 7 was reached. The plasma discharging characteristic was acquired in static flows. In a hypersonic flow, the flow field can affect the plasma discharging characteristics. DC discharging without magnetic force is unstable, and the discharge channel cannot be maintained. When there is a magnetic field, the energy consumption of the plasma source is approximately three to four times larger than that without a magnetic field, and at the same time plasma discharge can also affect the hypersonic flow field. Through schlieren pictures and pressure measurement, it was found that plasma discharging could induce shockwaves and change the total pressure and wall pressure of the flow field

401

Experimental investigation of different configurations in a flexible heliac  

International Nuclear Information System (INIS)

The effect of varying the magnetic configuration by adding an l = 1 helical winding to a standard heliac has been studied experimentally. Equilibrium plasma configurations are obtained in the range 0.7 ? ?(0) ? 1.86. Analysis of the plasma pressure profiles measured by Langmuir probes in this range all show good agreement between the plasma isobars and the computed vacuum magnetic surfaces; for configuration with ?(0) close to unity it is necessary to take a known error fields into account. The deterioration of the plasma confinement when low-order rational surfaces are present is clearly observed, and the magnetic islands which result from the resonance between the low-order rational surface ?=3/2, and the m=2,n=3 vacuum field harmonics inherent in the geometry are identified with features observed in both the plasma pressure and the floating potential profiles

402

Experimental investigation on laser milling of PMMA sheet  

Science.gov (United States)

In the present paper, laser milling tests were carried out by etching pockets of 10×10 mm2 on the surface of poly-methyl-methacrylate (PMMA) plate, 3 mm in thickness, using a 30 W CO2 laser source, working in continuous or pulsed regime. Aim of the work is to characterize the laser cutting process; or rather, to detect which and how the process parameters affect the depth of machined volume, the removed volume and the surface roughness. The milling tests were carried out changing the released energy, the wave mode (CW or PW), the scan speed, the distance between the linear patterns of two consecutive laser scans (step), the number of repetitions of the geometric pattern. Experimental results have shown that the depth and the machined volume linearly depend on the total amount of released energy. Furthermore, the surface roughness has been evaluated and discussed too.

Genna, S.; Leone, C.; Lopresto, V.; Tagliaferri, V.

2014-05-01

403

Experimental investigation of heat transfer in the transition region  

International Nuclear Information System (INIS)

An experimental study of forced convective boiling heat transfer for upflow of water in a circular tube has been performed using a heat transfer system with temperature-controlled indirect Joule heating. By this way, complete boiling curves from incipience of boiling to fully established film boiling could be measured including the transition boiling regime. The boiling curves were traversed in a quasi-steady mode, usually by increasing the set-point wall temperature average at a constant time rate of 3.5 K/min. The vast majority of results covers the pressure range from 0.1 to 1.0 MPa, mass flux range from 25 to 200 kg/(m2s) and inlet subcooling from 5 to 30 K. The experimental results of transition boiling heat transfer obtained in the centre of the test section were correlated in terms of a heat flux/surface superheat relationship that was normalized by the maximum heat flux (local CHF) and its associated wall superheat, respectively, to anchor the transition boiling curve to its low temperature limit. The upper surface temperature limit of the transition boiling regime was determined by inspection of measured axial distributions of surface heat flux and corresponding wall temperature. The critical heat flux (CHF) and its corresponding wall superheat has been measured, too. These temperature-controlled results were compared also with power-controlled experiments. The data are presented in terms of a table and accurate empirical correlations following Katto's generalized correlation scheme. Taking into account previous CHF data at L/D ? 100 and same range of flow conditions the length effect was found to further depend on pressure and mass flux. The data for the critical wall superheat show a distinct dependence upon pressure, mass flux and inlet quality that has not been observed before with comparable clarity

404

Experimental investigation of current free double layers in helicon plasmas  

International Nuclear Information System (INIS)

The paper presents investigations of current free double layer (CFDL) that forms in helicon plasmas. In contrast to the other work reporting on the same subject, in the present investigations the double layer (DL) forms in a mirror-like magnetic field topology. The RF compensated Langmuir probe measurements show multiple DLs, which are in connection with, the abrupt fall of densities along with potential drop of about 24 V and 18 V. The DLs strengths (e??Vp)/(k?Te) are about 9.5 and 6, and the corresponding widths are about 6 and 5 D lengths. The potential drop is nearly equal to the thermal anisotropies between the two plasma regions forming the DL, which is present in the plateau region of mirror, unlike the earlier studies on the DL formation in the region of strong gradients in the magnetic field. Also, it presents a qualitative discussion on the mechanism of DL formation

405

Experimental investigation of the classical Rayleigh-Taylor instability  

International Nuclear Information System (INIS)

The evolution of the Rayleigh-Taylor (RT) instability in a compressible medium has been investigated at an accelerating embedded interface and at the ablation front in a series of experiments on the Nova laser. The x-ray drive generated in a gold hohlraum ablatively accelerated a planar target consisting of a doped plastic pusher backed by a higher density titanium payload with perturbations placed at the plastic-Ti interface. The targets were diagnosed by face-on and side-on radiography. In previous work focusing on single mode perturbations, wavelengths as short as 10 m have been observed to grow strongly at the embedded interface. Here multimode perturbations consisting of either 2, 10 or 20 modes superposed in phase have been investigated

406

Exploratory experimental investigations on post-tensioned structural glass beams  

DEFF Research Database (Denmark)

This paper discusses two projects on post-tensioned glass beams, performed at EPFL and DTU, respectively. In these projects small scale glass beams (length of 1.5m and 1m) are post-tensioned by means of steel threaded rods tensioned at the beam ends. The purpose of post-tensioning glass beams is to enhance the initial failure stress of the glass and to obtain ductile (post-breakage) performance. From four-point bending tests on the post-tensioned glass beam specimens it is observed that these goals are reached. From the test results it is concluded that post-tensioning glass beams is a feasible and promising concept, which provides enhanced strength and ductile (post-breakage) performance. Since the current investigations are exploratory, the investigated concepts leave unsolved challenges for future research within this field.

Louter, C.; Nielsen, Jens Henrik

2013-01-01

407

EXPERIMENTAL INVESTIGATION OF 2kW HIGH PRESSURE GASIFIER  

OpenAIRE

In a gasifier, the main attractive factors are the design and the operation. An optimized gasification process produces a considerably clean gas without additional energy. So a double walled gasifier combining the features of a closed top and an open top gasifier was developed and the performance behavior was investigated at different operating pressures. The gasifier has a total height of 1500mm, made of stainless steel with internal diameter of 196mm and thickness of 4.2mm. A conical sectio...

Mohanraj, C.; Ezhil, J.

2013-01-01

408

Adhesive bonding of discontinuous carbon fibre composites: an experimental investigation  

OpenAIRE

The excellent specific stiffness and strength of carbon fibre reinforced polymer composites means that the automotive sector has been investigating methods of implementing these materials into structurally demanding applications. The work detailed within this thesis supports ongoing research at the University of Nottingham into the automated manufacture of discontinuous carbon fibre reinforced polymer composite materials. Advances in the automation of composites manufacturing has meant that m...

Nicholls, Tristan Kit

2013-01-01

409

Experimental investigation of unsteadiness in transonic shock boundary layer interaction  

OpenAIRE

Transonic shock wave/boundary layer interaction over a wall-mounted bump was investigated with specific focus on shock wave unsteadiness and identification of its source. A large separation bubble resulted of an interaction driven by a flow characterized by a peak Mach number of 1.365. Overall this particular type of transonic unsteadiness is characterized with low amplitude and relatively high frequency motion. Low frequency shock unsteadiness was optically estimated and matched spectral con...

Benard, Emmanuel; Huang, Jui-che; Raghunathan, Srinivasan

2010-01-01

410

Experimental investigation of the shear capacity of plastic hinges  

OpenAIRE

The influence of plastic strains in the longitudinal reinforcement in presence of high shear forces in beams and slabs without stirrups was investigated performing a series of tests of eight ordinary reinforced concrete beams 8.4 meters long with 0.79% reinforcement ratio. The tests show that the shear capacity of plastic hinges decreases with increasing rotation. The article presents a description of the tests along with the main preliminary results.

Vaz Rodrigues, Rui; Burdet, Olivier; Muttoni, Aurelio

2005-01-01

411

Experimental Investigation of Turbulent Fluid Flow through a Rectangular Elbow  

Directory of Open Access Journals (Sweden)

Full Text Available The analysis of the turbulent fluid flow in a rectangular elbow is important for many engineering applications like heatexchanger, fluid transport piping system, air conditioning devices etc. Present study investigates the flow visualization of turbulentfluid flow through a rectangular elbow and estimation of co-efficient of friction. The working fluid is air and flow taken to be isincompressible, turbulent and non-reacting. The velocity profiles along the elbow duct are observed at Reynolds number of3.8

Arindam Mandal

2010-06-01

412

Experimental investigation of colloidal and microbiological effect for geological disposal  

International Nuclear Information System (INIS)

In order to know the characteristics of nuclide transfer in bentonites, which are taking attraction as a buffering material it seems essential to clarify the structure of compressed bentonites. Since the movements of various colloids and microorganisms in bentonite are greatly influenced by its pore size, the size is thought to be closely related to the transfer of nuclides in it. In this study, the effects of pore size were investigated in respect of the permeabilities for microorganisms and colloids. Gold colloids (grain size; 15 mm) were not transferred in a compressed bentonite with dry density of 1000 kg/m3, whereas those were permeable to the bentonite mixed with silica sand at 50% (w/w) for the dry density of 1000 kg/m3 but not permeable to that for 1800 kg/m3. Microbial resistance of compressed bentonite was studied in a deep geologic environment. The growths of sulfate-reducing bacteria and methane-producing bacteria were investigated in a fermenter, showing that the environment similar to actual conditions for geological disposal is habitable for these bacteria. But, it is assumed these bacteria larger than the gold colloid can not move in the environment. Therefore, it seems necessary in future to investigate bacterial effects outside of the bentonite. (M.N.)

413

EXPERIMENTAL INVESTIGATIONS OF BEARING CAPACITY FOR ECCENTRICALLY LOADED FOOTING  

Directory of Open Access Journals (Sweden)

Full Text Available The present work tries to investigate the bearing capacity of eccentrically loaded footing. Footings of different size and shape are used for testing. Testing for bearing capacity of centrally loaded footing and then for eccentrically loaded footing with different ‘e/B’ ratio is carried out. For every footing bearing capacity and settlement has been found out for central as well as eccentric loading. These results of central and eccentric loading are compared with each other for same footing. The results of different footings are also compared for central and eccentric loading. By comparing these results effect of eccentricity, size and shape of footing on bearing capacity has been investigated. In the present study prefabricated model footings and the metal strips are used on the footing for applying eccentric loading. The load has been applied by using hydraulic jack of 20 KN capacity. Two dial gauges are used for measuring settlement, which are arranged diagonally on footing. The results of the previous investigators are also analyzed and compared with the proposed theory. A reasonable agreement was found between the theory and the test data.

S. M. NAWGHARE

2010-10-01

414

Experimental investigation of H2 combustion in the Sandia VGES intermediate-scale burn tank  

International Nuclear Information System (INIS)

Sandia National Laboratories is presently involved in several NRC-sponsored experimental projects to provide data that will help quantify the threat of hydrogen combustion during LWR accidents. One project, which employs several experimental facilities: is the Variable Geometry Experimental System (VGES). The purpose of this paper is to present the experimental results from one of these facilities; the intermediate-scale burn tank (approx.5m3). The data provided by this facility can be used in the development and assessment of analytical models used to predict hydrogen combustion behavior

415

INVESTIGATION OF NEW TECHNIQUES FOR CONTROL OF SMELTER ARSENIC BEARING WASTES. VOLUME I: EXPERIMENTAL PROGRAM  

Science.gov (United States)

In 1976, the Industrial Environmental Research Laboratory at Cincinnati sponsored a research program at the Mineral Research Center, Montana Tech Alumni Foundation, to investigate a variety of approaches to the fixation of arsenic bearing wastes, particularly smelter flue dusts, ...

416

Inquiry-based laboratory investigations and student performance on standardized tests in biological science  

Science.gov (United States)

Achievement data from the 3rd International Mathematics and Sciences Study and Program for International Student Assessment in science have indicated that Black students from economically disadvantaged families underachieve at alarming rates in comparison to White and economically advantaged peer groups. The study site was a predominately Black, urban school district experiencing underachievement. The purpose of this correlational study was to examine the relationship between students' use of inquiry-based laboratory investigations and their performance on the Biology End of Course Test, as well as to examine the relationship while partialling out the effects of student gender. Constructivist theory formed the theoretical foundation of the study. Students' perceived levels of experience with inquiry-based laboratory investigations were measured using the Laboratory Program Variable Inventory (LPVI) survey. LPVI scores of 256 students were correlated with test scores and were examined by student gender. The Pearson correlation coefficient revealed a small direct correlation between students' experience in inquiry-based laboratory investigation classes and standardized test scores on the Biology EOCT. A partial correlational analysis indicated that the correlation remained after controlling for gender. This study may prompt a change from teacher-centered to student-centered pedagogy at the local site in order to increase academic achievement for all students. The results of this study may also influence administrators and policy makers to initiate local, state, or nationwide curricular development. A change in curriculum may promote social change as students become more competent, and more able, to succeed in life beyond secondary school.

Patke, Usha

417

Experimental investigation of the magnetochiral index in liquids  

International Nuclear Information System (INIS)

We showed through experiments that the magnetochiral index is polarization invariant and reported its wavelength dependence. These properties were investigated with limonene and using a specially-designed Ar+-ring active interferometer. A Fresnel drag-type optical bias inside the discharge tube, combined with two calibrations and the circumvention of systematic errors, allowed us to reach a detection level in the range of 10-12 when measuring the change in the magnetochiral index of intracavity liquid samples. Our results are in agreement with the different predictions made for magnetochiral refraction

418

Experimental investigation of ?-ray attenuation coefficients for granites  

International Nuclear Information System (INIS)

Highlights: ? Radiation shielding properties of granites have been investigated. ? This is done by measuring linear attenuation coefficients. ? Measurement was performed using 137Cs and 60Co sources. - Abstract: The linear attenuation coefficients of ?-rays for some granite samples have been measured at 662, 1773 and 1332 keV. The ?-rays have been obtained from 137Cs and 60Co sources respectively and the measurement have been performed using a gamma spectrometer which contains 3” × 3” NaI(Tl) detector connected to 16384 channel Multi-Channel-Analyser (MCA).

419

Experimental investigation of radionuclide transport in the Arctic Ocean  

International Nuclear Information System (INIS)

The project task is to investigate and quantify the transport of radioactively contaminated sediments from Novaya Zemlya and the Kara Sea to other arctic regions by the transport medium 'Arctic Ocean ice'. It is expected that transport of radioactive environmental materials through the ice masses forming in this region plays a more important role than transport through sea currents, which would involve dilution of dissolved radionuclide concentrations. Also, transport by the ice masses is much faster than water-borne transport, so that the radioactivity could be released much earlier in the area east of Greenland. (orig./CB)

420

Experimental Investigation of Integrated Optical Intensive Impulse Electric Field Sensors  

International Nuclear Information System (INIS)

We design and fabricate an integrated optical electric field sensor with segmented electrode for intensive impulse electric field measurement. The integrated optical sensor is based on a Mach–Zehnder interferometer with segmented electrodes. The output/input character of the sensing system is analysed and measured. The maximal detectable electric field range (?75 kV/m to 245 kV/m) is obtained by analysing the results. As a result, the integrated optics electric field sensing system is suitable for transient intensive electric field measurement investigation