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

2

Experimental Investigation of Beam Breakup in the Jefferson Laboratory 10 kW FEL Upgrade Driver  

Science.gov (United States)

In energy recovery linacs the maximum average current can be limited by the multipass beam breakup (BBU) instability, 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 recovered pass. Experimental characterization and observations of the instability at the Jefferson Laboratory 10 kW Free Electron Laser (FEL) Driver are presented. Methods to measure the threshold current for the instability were developed and the results were used to compare with the predictions of several BBU simulation codes. This represents the first time in which the codes have been definitively benchmarked. With BBU posing a threat to high current beam operation in the FEL Driver, several suppression schemes were successfully developed. These include direct damping of the dangerous HOM and appropriately modifying the electron beam optics so as to reduce the coupling between the beam and mode.

Tennant, Christopher; Douglas, David; Jordan, Kevin; Merminga, Lia; Pozdeyev, Eduard; Wang, Haipeng

2006-04-01

3

Experimental investigation of multibunch, multipass beam breakup in the Jefferson Laboratory Free Electron Laser Upgrade Driver  

Science.gov (United States)

In recirculating accelerators, and, in particular, energy-recovery linacs, 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. These include direct damping of the dangerous HOM using cavity feedback and modifying the electron beam optics so as to reduce the coupling between the beam and mode. Both methods were shown to increase the threshold current for stability. Beam optical suppression techniques, in particular, have proved to be so effective that they are routinely used in the normal operations of the FEL Upgrade Driver.

Douglas, David R.; Jordan, Kevin C.; Merminga, Lia; Pozdeyev, Eduard G.; Tennant, Christopher D.; Wang, Haipeng; Smith, Todd I.; Simrock, Stefan; Bazarov, Ivan V.; Hoffstaetter, Georg H.

2006-06-01

4

A Remote Laboratory Experimentation Network.  

OpenAIRE

This contribution presents a remote laboratory project with a new business model that aims at bringing physical experimentation back into the learning arena, where remotely operable laboratory experiments used in advanced education and training schemes are made available to a global market. This is done via the Internet using a set of e-commerce and advanced information and communication technology solutions. The project will add online remote experimentation to distance learning techniques. ...

Schmid, C.; Eikaas, T. I.; Foss, B.; Gillet, D.

2001-01-01

5

Theoretical investigations of experimental gravitation  

International Nuclear Information System (INIS)

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

6

An Experimental Investigation of the Role of Radiation in Laboratory Bench-Top Experiments in Thermal Physics  

Science.gov (United States)

A simple undergraduate experiment designed to study cooling purely by radiation and cooling by a combination of convection and radiation is described. Results indicate that the contribution from radiative cooling in normal laboratory experiments is more significant than students often realize, even in the case of forced cooling. (Contains 1…

Twomey, Patrick; O'Sullivan, Colm; O'Riordan, John

2009-01-01

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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.

8

Experimental facility of innovative types as the laboratory analog of research reactor experimental device  

International Nuclear Information System (INIS)

The paper analyses capability of creating laboratory analogs of complex experimental facilities at research reactors utilizing power radionuclide neutron sources fabricated in industrial conditions. Some experimental and calculational investigations of neutron-physical characteristics are presented, which have been attained at the RIZ research reactor laboratory analog. Experimental results are supplemented by calculational investigations, fulfilled by means of the BRAND three-dimensional computational complex and the ROZ-6 one-dimensional program. 4 refs.; 3 figs

9

Experimental investigation on a laboratory-scale model of the fluid-pipe interaction on catenary risers for offshore petroleum production  

Energy Technology Data Exchange (ETDEWEB)

A laboratory-scale model was designed to investigate the influence of the internal flow of two-phase oil and gas mixtures on the motion of slender risers hanging in catenary configuration used for offshore petroleum production in deep waters. The internal flow mass and momentum may impose a natural whipping displacement - compounding swinging and bending - adding to the concerns of stress and fatigue. The internal flow may display different two-phase patterns (bubbles, slugs, intermittent, annular or stratified mixtures) possessing completely different characteristics; also, the fluids' dynamic loading depends on the flow rates of both oil and gas phases. This research attempts to discern the effects of the internal flow, discriminating it from the other dynamic phenomena. Accelerometers and video acquisition were employed to verify the phenomenon and to determine the frequency spectrum of the oscillations. (author)

Cavalcante, C.C.P.; Bordalo, S.N.; Morooka, C.K. [Universidade de Campinas (UNICAMP), SP (Brazil). Dept. de Engenharia de Petroleo], E-mail: bordalo@dep.fem.unicamp.br; Matt, C.G.C.; Franciss, R. [Petroleo Brasileiro S.A. (CENPES / PETROBRAS), Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

2007-10-15

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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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Laboratory Investigations into the Extreme Universe  

CERN Document Server

Recent years have seen tremendous progress in our understanding of the extreme universe, which in turn points to even deeper questions to be further addressed. History has shown that the symbiosis between direct observations and laboratory investigations is instrumental in the progress of astrophysics. Current frontier astrophysical phenomena related to particle astrophysics and cosmology typically involve one or more of the following conditions: (1) extremely high energy events;(2) very high density, high temperature processes; (3) super strong field environments. Laboratory experiments using high intensity lasers and particle beams can calibrate astrophysical observation or detection processes, investigate the underlying dynamics of astrophysical phenomena, and probe fundamental physics in extreme limits. We give examples of possible laboratory experiments that investigate into the extreme universe.

Chen, P

2003-01-01

12

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

13

Experimental Investigations on Market Behavior  

OpenAIRE

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

Z?akelj, Blaz?

2012-01-01

14

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)

15

Experimental Investigation of Microstructured Evaporators  

Science.gov (United States)

Microfluidic devices have become more and more popular over the last decades [1]. 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 [2]. 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 [2] for the evaporation of R134a in straight microchannels.

Wibel, W.; Westermann, S.; Maikowske, S.; Brandner, J. J.

2012-11-01

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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 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 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

19

Experimental investigations of the nuclear structure  

International Nuclear Information System (INIS)

The problem of experimental investigation into atomic nucleus structure is discussed. Examples of studying the properties of low-lying nucleus states using cyclotron-type accelerators for their production are presented. The consideration is conducted on the base of the Idisol experimental complex created at the Finland. Results of measuring masses of neutron-redundant rubidium nuclei are presented. Schemes of 160Er and 108In decay are presented. 12 refs.; 6 figs

20

Numerical and Experimental Investigation of Tidal Current Energy Extraction  

OpenAIRE

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

Sun, Xiaojing

2008-01-01

21

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)

22

Black swan protection: an experimental investigation  

OpenAIRE

This experimental study investigates insurance decisions in low-probability, high-loss risk situations. Results indicate that subjects consider the probability of loss (loss size) when they make buying decisions (paying decisions). Most individuals are risk averse with no specific threshold probability.

Morone, Andrea; Ozdemir, Ozlem

2012-01-01

23

Experimental and theoretical investigations of wet flue gas desulphurisation  

Energy Technology Data Exchange (ETDEWEB)

This thesis describes experimental and theoretical investigations of wet flue gas desulphurisation (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 different origin were tested. A transient, mass transport controlled, mathematical model was developed to describe the dissolution process. Model predictions were found to be qualitatively in good agreement with experimental data. Empirical correlations for the dimensionless mass transfer coefficients in a pilot plant (falling-film column) were determined. A detailed model for a wet FGD pilot plant, based on the falling film principle, was developed. All important rate determining steps, absorption of SO{sub 2}, oxidation of HSO{sub 3}{sup -}, dissolution of limestone, and crystallisation of gypsum were included. Pilot-scale experiments were initiated to investigate the possibility of oxidising spray dry scrubber by-products (TASP) to gypsum in wet FGD plants. The results of this work demonstrate that mathematical modelling can be a powerful tool in the process of obtaining a detailed understanding of the complex interactions between chemical reactions and mass transport phenomena in wet FGD plants. (EG) EFP-95. 44 refs.

Kiil, Soeren

1998-12-31

24

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

25

Fusion of Laboratory and Textual Data for Investigative Bioforensics  

Energy Technology Data Exchange (ETDEWEB)

Chemical and biological forensic programs focus on the identification of a threat and acquisition of laboratory measurements to determine how a threat agent may have been produced. However, to generate investigative leads, it might also be useful to identify institutions where the same agent has been produced by the same or a very similar process, since the producer of the agent may have learned methods at a university or similar institution. We have developed a Bayesian network framework that fuses hard and soft data sources to assign probability to production practices. It combines the results of laboratory measurements with an automatic text reader to scan scientific literature and rank institutions that had published papers on the agent of interest in order of the probability that the institution has the capability to generate the sample of interest based on laboratory data. We demonstrate the Bayesian network on an example case from microbial forensics, predicting the methods used to produce Bacillus anthracis spores based on mass spectrometric measurements and identifying institutions that have a history of growing Bacillus spores using the same or highly similar methods. We illustrate that the network model can assign a higher posterior probability than expected by random chance to appropriate institutions when trained using only a small set of manually analyzed documents. This is the first example of an automated methodology to integrate experimental and textual data for the purpose of investigative forensics.

Webb-Robertson, Bobbie-Jo M.; Corley, Courtney D.; McCue, Lee Ann; Wahl, Karen L.; Kreuzer, Helen W.

2013-03-10

26

Fusion of laboratory and textual data for investigative bioforensics.  

Science.gov (United States)

Chemical and biological forensic programs focus on the identification of a threat and acquisition of laboratory measurements to determine how a threat agent may have been produced. However, to generate investigative leads, it might also be useful to identify institutions where the same agent has been produced by the same or a very similar process, since the producer of the agent may have learned methods at a university or similar institution. We have developed a Bayesian network framework that fuses hard and soft data sources to assign probability to production practices. It combines the results of laboratory measurements with an automatic text reader to scan scientific literature and rank institutions that had published papers on the agent of interest in order of the probability that the institution has the capability to generate the sample of interest based on laboratory data. We demonstrate the Bayesian network on an example case from microbial forensics, predicting the methods used to produce Bacillus anthracis spores based on mass spectrometric measurements and identifying institutions that have a history of growing Bacillus spores using the same or highly similar methods. We illustrate that the network model can assign a higher posterior probability than expected by random chance to appropriate institutions when trained using only a small set of manually analyzed documents. This is the first example of an automated methodology to integrate experimental and textual data for the purpose of investigative forensics. PMID:23313599

Webb-Robertson, Bobbie-Jo; Corley, Courtney; McCue, Lee Ann; Wahl, Karen; Kreuzer, Helen

2013-03-10

27

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

28

Experimental investigation of thermosyphon loop thermal performance  

International Nuclear Information System (INIS)

Highlights: • Experimental investigations are conducted on the thermal performance of the passive loop. • The loop fill charge ratio affected the loop start-up and showed an optimal value between 7% and 10%. • The condenser power effect on the loop thermal performance is studied. • The condenser jacket coolant optimal temperature and flow rate are studied. - Abstract: This paper presents the experimental investigation of a two-phase closed loop. The experimental setup consists of an evaporator and a condenser connected by two insulated tubes. Using water as a working fluid, the experiments were conducted to evaluate the performance of a thermosyphon: the effects of fill charge ratio, the condenser jacket coolant inlet temperature and the mass flow rate. Finally, the results show that the optimal fill charge ratio is between 7% and 10%, the cooling system has the optimal performance when controlling the condenser jacket water temperature and flow rate at 5 °C and at 0.7 l/min respectively. System, loop, evaporator, vapor line, condenser, and liquid line thermal resistances analysis is directed additionally to the pressure and temperature evolutions for the better understand of the main parameters affecting the cooling system performance

29

Health Evaluation of Experimental Laboratory Mice  

OpenAIRE

Good science and good animal care go hand in hand. A sick or distressed animal does not produce the reliable results that a healthy and unstressed animal produces. This unit describes the essentials of assessing mouse health, colony health surveillance, common conditions, and determination of appropriate endpoints. Understanding the health and well-being of the mice used in research enables the investigator to optimize research results and animal care.

Burkholder, Tanya; Foltz, Charmaine; Karlsson, Eleanor; Linton, C. Garry; Smith, Joanne M.

2012-01-01

30

The European Network of Analytical and Experimental Laboratories for Geosciences  

Science.gov (United States)

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

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

2013-04-01

31

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.

2002-10-01

32

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

33

Experimental investigation of spiral seam induction bends  

Energy Technology Data Exchange (ETDEWEB)

The induction bend is a connecting piece widely used in the pipeline industry. The stress produced by the welding process is significant. This paper reports the experimental investigation of spiral seam induction bends. Three dimension X52 SSAW pipes were used as mother pipes to manufacture the bends through the induction bending process. The study of the spiral seam induction bend used a destructive test sampling plan, which embraces the typical zones of spiral seam induction bend. The study of the mechanical properties and structure of the spiral seam induction bends was performed using Charpy impact test, tensile tests and design proof test. The results showed that the strength-toughness of a spiral seam induction bend approaches the property of mother pipe when the appropriate process is adopted. The guided weld bend tests results also showed that it is difficult to make induction bends with small diameter SSAW pipes.

Chi, Qiang; Wang, Peng; Liu, Yinglai; Ji, Lingkang; Gong, Shaotao [Tubular Goods Research Center, CNPC, Xi' an, (China)

2010-07-01

34

Experimental investigation of Reykjavik city footbridge  

DEFF Research Database (Denmark)

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

Zivanovic, Stana; Ingólfsson, Einar Thór

2011-01-01

35

Experimental Investigations of the Lunar Photoelectron Sheath  

Science.gov (United States)

Solar ultraviolet radiation incident upon the dayside lunar surface produces a photoelectron gas that dominates the near-surface plasma environment, with a typical density of 60 cm-3 and a characteristic scale-length of ~1 m. It has traditionally been difficult to produce a photoelectron gas with sufficient density in a laboratory settings to study its properties. In our initial experiments, the characterization of the photoelectron density above a Zr surface (work function W=4.4 eV) illuminated by Xe excimer lamps (peak emission at a wavelength of 172 nm) indicated that a sheath with a Debye length on the order of 10 cm formed. We characterize the photoelectron population above the surface by utilizing an emissive probe to map the electric potential distribution above the surface, and a Langmuir probe to determine the number density and temperature of the photoelectrons. A grid is placed 7.5 cm above the Zr surface to repel photoelectrons emitted from the chamber walls. Emissive probe measurements show a potential dip of about 2 V extending ~1 cm above the zirconium surface. The size of this potential well is dependent on the number of lamps illuminating the surface, as the density of photoelectrons above the surface increases with greater illumination. The electrons in the sheath have a Maxwellian distribution with an electron temperature around 1 eV (maximum energies are expected to be approximately 2.8 eV). We will use this experimental apparatus to characterize the photoelectron sheath above other surfaces; powders, such as CeO2 have similar work functions, but different photoelectric yields. Lunar soil simulants are expected to have approximately an order of magnitude smaller yield than metallic surfaces, which will act to increase the characteristic length of the photoelectron sheath above the surface. The experiments and accompanying computer simulations are used to guide the development of new instrument concepts for future in situ plasma measurements on the lunar surface.

Dove, A.; Sternovsky, Z.; Wang, X.; Robertson, S. H.; Lapanse, C.; Horanyi, M.; Collette, A.

2010-12-01

36

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

37

Experimental Investigation of Transient Sublimator Performance  

Science.gov (United States)

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

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

2012-01-01

38

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

39

Experimental investigation of wingtip aerodynamic loading  

Science.gov (United States)

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

Van Aken, Johannes M.

1990-01-01

40

Laboratory investigations in cell biology. Second edition  

Energy Technology Data Exchange (ETDEWEB)

This text contains 18 lab projects that explore the structural, biochemical, and physiological nature of eukaryotic cells. Topics are largely traditional, however, several investigations employ new methodologies. Offers extended coverage of biochemistry. Materials have been selected for availability and ease of handling: e.g. Project 4 - extraction of DNA and RNA done with calf liver, Project 9 - succinate dehydrogenase activity studied in mitochondria isolated from cauliflower. There is more procedural detail than found in most lab manuals, negating the need for constant instructional details. And a variety of methodologies is introduced, such as Cytochemistry, Spectrophotometry, Electrophoresis, Cell Fractionation, silver staining of active sites of RNA transcription, and many more. Pages are perforated for collecting and grading.

Bregman, A.A.

1987-01-01

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 on dry stone masonry walls  

OpenAIRE

Brick unreinforced masonry walls have been widely studied both from experimental and numerical point of view, but scarce experimental information is available for dry stone masonry walls that constitute the material more frequently used in the construction of ancient historical constructions. Therefore, the present work aims at increasing the insight about the behavior of typical ancient masonry walls under cyclic loading. To attain such goal, different experimental approaches are consi...

Vasconcelos, Grac?a; Lourenc?o, Paulo B.; Mouzakis, H.; Karapitta, L.

2006-01-01

43

Hydrochemical laboratory methods for Nagra's investigation programme  

International Nuclear Information System (INIS)

Nagra's geological research program is directed toward determination of the possibilities for depositing high level radioactive waste at depth in Northern Switzerland. The program includes ground water analyses for chemical and biological constituents (analyses by Institut Fresenius) as well as for dissolved gases, uranium, and natural radioactivity (analyses by EIR, Eidgenoessisches Institut fuer Reaktorforschung). Two sources were utilized to obtain formation water chemistry in the study area. A regional program was established to investigate mineral and thermal waters. 17 sites of the regional program are scheduled for long term monitoring of water chemistry. A deep drilling program (12 locations projected) was initiated to obtain and analyze water samples from defined depths and formations under in situ conditions. Chapter 2 presents the analytical programs in detail. General chemistry was determined in all samples. In the regional program, well equipped wells and springs provided representative samples at most locations (cf chapter 3). However, at other locations impairment of sample quality could not be avoided. Given sufficient water flow, samples for the deep drilling program were taken both at the earth's surface under atmospheric pressure conditions (from artesian outflow or after pumping), and under formation pressure at various depths with specialized sample containers (chapter 3.7.3). Chapter 4 gives a listing of all analytical methods used in the study, their accuracy ranges and detection limits. Finally, this paper also presents some special problems encountered during the deep drilling program (cf chapter 5). Preliminary results show that no single method can provide completely satisfactory results for all deep drilling water sampling. A combination of procedures and critical evaluation of their respective data can, however, provide valuable information on the chemistry of waters from certain formations. (author)

44

Computational and experimental investigation of spiral concentrator flows  

Energy Technology Data Exchange (ETDEWEB)

Spiral concentrators are used globally in the fine coal processing industry to segregate particles, by gravitation, on the basis of density and size. Consisting of an open trough that twists vertically downwards about a central axis, a slurry mix of particles and water is fed to the top of the concentrator. Particles are then separated radially as they gravitate downward. Since their introduction to Australia in the 1940`s, the generic design has evolved largely by laboratory trial-and-error investigations of different prototypes. However, this approach has proven expensive and optimal designs have not been necessarily developed. Accordingly, Computational Fluid Dynamics (CFD) analysis has been used recently as an alternative method of investigation, to assume as is envisaged, a role in the design process. To date, CFD models have progressed to simulations of turbulent flow on current production spiral designs, and are continuing to be adapted for inclusion of particles at realistic feed concentrations. To be able to use the models confidently however, laboratory experiments must also be performed to validate the predictions during the development stage. This paper reports the current findings of an ongoing CFD and experimental program applied to one spiral unit. Satisfactory quantitative agreement has been achieved for the fluid and particulate flow characteristics, and although further validations are appropriate, the model already possesses significant potential for use as a reliable predictive design tool. 9 refs., 6 figs.

Matthews, B.W.; Holtham, P.; Fletcher, C.A.J.; Golab, K.; Partridge, A.C. [University of New South Wales, Sydney, NSW (Australia). CANCES

1998-12-31

45

Experimental Investigation of Flow Condensation in Microgravity  

Science.gov (United States)

Future manned missions to Mars are expected to greatly increase the space vehicle's size, weight, and heat dissipation requirements. An effective means to reducing both size and weight is to replace single-phase thermal management systems with two-phase counterparts that capitalize upon both latent and sensible heat of the coolant rather than sensible heat alone. This shift is expected to yield orders of magnitude enhancements in flow boiling and condensation heat transfer coefficients. A major challenge to this shift is a lack of reliable tools for accurate prediction of two-phase pressure drop and heat transfer coefficient in reduced gravity. Developing such tools will require a sophisticated experimental facility to enable investigators to perform both flow boiling and condensation experiments in microgravity in pursuit of reliable databases. This study will discuss the development of the Flow Boiling and Condensation Experiment (FBCE) for the International Space Station (ISS), which was initiated in 2012 in collaboration between Purdue University and NASA Glenn Research Center. This facility was recently tested in parabolic flight to acquire condensation data for FC-72 in microgravity, aided by high-speed video analysis of interfacial structure of the condensation film. The condensation is achieved by rejecting heat to a counter flow of water, and experiments were performed at different mass velocities of FC-72 and water and different FC-72 inlet qualities. It is shown that the film flow varies from smooth-laminar to wavy-laminar and ultimately turbulent with increasing FC-72 mass velocity. The heat transfer coefficient is highest near the inlet of the condensation tube, where the film is thinnest, and decreases monotonically along the tube, except for high FC-72 mass velocities, where the heat transfer coefficient is enhanced downstream. This enhancement is attributed to both turbulence and increased interfacial waviness. One-ge correlations are shown to predict the average condensation heat transfer coefficient with varying degrees of success, and a recent correlation is identified for its superior predictive capability, evidenced by a mean absolute error of 21.7%.

Lee, Hyoungsoon; Park, Ilchung; Konishi, Christopher; Mudawar, Issam; May, Rochelle I.; Juergens, Jeffery R.; Wagner, James D.; Hall, Nancy R.; Nahra, Henry K.; Hasan, Mohammed M.; Mackey, Jeffery R.

2013-01-01

46

Role of vegetation on erosion processes: experimental investigation  

Science.gov (United States)

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

Termini, Donatella

2014-05-01

47

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

48

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

49

An Experimental Investigation of Cognitive Defusion  

Science.gov (United States)

The current study compared cognitive defusion with other strategies in reducing the impact of experimentally induced negative emotional states. Sixty-seven undergraduates were assigned to one of three conditions (cognitive defusion, thought suppression, or control) and instructed in standardized approaches relevant to each condition before viewing…

Pilecki, Brian C.; McKay, Dean

2012-01-01

50

An Open-Ended Investigative Microbial Ecology Laboratory for Introductory Biology  

Science.gov (United States)

In this article we describe a multi-week investigative laboratory in microbial ecology/diversity and nitrogen cycling that we have used in our introductory biology course. This module encourages active student involvement in experimental design, using the scientific literature and quantitative analysis of large data sets. Students analyze soil…

Jones-Held, Susan; Paoletti, Robert; Glick, David; Held, Michael E.

2010-01-01

51

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

Science.gov (United States)

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

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

2012-01-01

52

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.

53

Experimental investigation of consumer price evaluations  

OpenAIRE

We develop a procedure to collect experimental choice data for estimating consumer preferences with a special focus on consumer price evaluations. For this purpose we employ a heteroskedastic mixed logit model that measures the effect of the way prices are specified on the variance of choice. Our procedure is based on optimal design ideas from the statistics literature and on some algorithms for constructing choice designs published in marketing journals. In an empirical application on mobile...

Sa?ndor, Z.; Franses, Ph H. B. F.

2004-01-01

54

Experimental investigation of cryogenic oscillating heat pipes.  

Science.gov (United States)

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

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

2009-07-01

55

Experimental actinomycetoma due to Nocardia transvalensis in laboratory mice.  

Science.gov (United States)

Nocardia transvalensis was investigated for its ability to cause mycetoma in the skin and foot pad of laboratory mice. Freund's incomplete adjuvant appeared to aid the development of mycetoma lesions. The infection manifested itself as palpable nodules under the skin which discharged white to cream coloured pus containing nocardial granules. The lesions in the skin necrotized, while those of foot pad resulted in bone destruction. PMID:2352546

Unaogu, I C; Gugnani, H C; Ikerionwu, S E

1990-02-01

56

Experimental investigation of 6Be cluster decay  

International Nuclear Information System (INIS)

A complete kinematics measurement was performed using the 6Li(3He,t) charge exchange reaction to populate 6Be at Elab = 50 MeV. Decay mode of the ground and first excited states were studied through the analysis of the energy and angular distributions of the break-up particles in the 6Be center of mass frame. Two-body decay is observed above the first excited state but not firmly assigned to a 6Be resonant state. Experimental challenges regarding the identification of true 6Be events in the excitation energy region 5 x < 20 MeV are discussed. (author)

57

Experimental investigation of radioprotective properties of nanodiamonds  

International Nuclear Information System (INIS)

Radioprotective effect of oral administration of water suspension of nanodiamonds before x-ray exposure at a dose of 6.0 Gy was analyzed experimentally on white mongreal female rats weighing 180-210 g. The effects were traced on day 3, 7, 14, 30 using radiobiological, hematological, biochemical and pathoanatomical methods. Owing to radiation protection of the cells of the gastrointestinal tract, water suspension of ultradisperse diamonds of detonation synthesis possesses a marked radioprotective effect on the rats exposed to lethal dose. The state of other inner organs, hemopoietic system and the levels of a number of metabolism parameters in the exposed animals depend less on preliminary administration of ND.

58

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

59

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

60

Investigating properties of white noise in the undergraduate laboratory  

International Nuclear Information System (INIS)

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

61

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

62

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

63

A research-inspired laboratory sequence investigating acquired drug resistance  

OpenAIRE

Here, we present a six-session laboratory exercise designed to introduce students to standard biochemical techniques in the context of investigating a high impact research topic, acquired resistance to the cancer drug Gleevec. Students express a Gleevec-resistant mutant of the Abelson tyrosine kinase domain, the active domain of an oncogenic protein implicated in chronic myelogenous leukemia, and investigate the kinase activity of wild type and mutant enzyme in the presence of two cancer drug...

Taylor, Elizabeth Vogel; Fortune, Jennifer A.; Drennan, Catherine L.

2009-01-01

64

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

65

Theoretical and experimental investigations of Chinese evacuated tubular solar collectors  

DEFF Research Database (Denmark)

Four different marketed Chinese evacuated tubular solar collectors have been investigated both theoretically and experimentally. The advantages of the investigated solar collectors compared to normal flat plate collectors were elucidated.

Qin, Lin; Furbo, Simon

1999-01-01

66

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

67

Experimental Investigation of Orthoenstatite Single Crystal Rheology  

Science.gov (United States)

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

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

2013-12-01

68

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 and experimental 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 and Ternary Nucleation. 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. Recent experimental work 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 link between 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 Technical University of Denmark,

69

Experimental investigation of a flapping wing model  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-05-15

70

Experimental Investigation on Liquid Behaviors in Nanopores  

Science.gov (United States)

Nanoporous materials are involved in many industrial processes such as catalysis, filtration, chromatography, etc. Recently, they are applied to absorb or capture the energy associated with blast, collision, and impact attacks. In such applications, the nanoporous materials are immersed in liquids or gels. The inner surfaces of nanopores are usually modified to increase the degree of hydrophobicity. When an external pressure is applied on the system, the liquid phase can be compressed into the nanoporous space. The liquid infiltration behavior in the nanopores becomes significantly different from that of untreated material. The effective interfacial tension and viscosity of the confined liquid are investigated. While the simple superposition principle can be employed for the analysis of interfacial tension, in a nanopore the effective liquid viscosity is no longer a material constant. It is highly dependent on the pore size and the loading rate, much smaller than its bulk counterpart. In addition, the influence of electrolyte concentration as well as its dependence on temperature are analyzed in detail. As the electrolyte concentration varies, the effective interfacial tension changes rapidly. The testing data show that, the pressure-induced infiltration behavior is not only determined by the cations, but also highly dependent on the anion species. The transport behaviors of solvated ions in nanopores can be field responsive, providing a novel method to develop interactive protection systems. As an external electric field is applied, the observed change in effective solid-liquid interfacial tension is contradictory to the prediction of classic electrochemistry theory. To simplify the materials handling, a polypropylene-matrix composite material is produced. When the temperature is relatively low, the matrix dominates the system behavior. When the temperature is relatively high, with a sufficiently large external pressure the polymer phase can be intruded into the nanopores, providing an energy absorption mechanism.

Lu, Weiyi

71

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

72

Experimental analysis of nonlinear oscillations in the undergraduate physics laboratory  

International Nuclear Information System (INIS)

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

73

Growth of laboratory populations of tsetse flies. Some mathematical investigations  

International Nuclear Information System (INIS)

The growth of laboratory populations of Glossina palpalis is described by a discrete time model. The model parameters are calculated from a life and fertility table derived from records of 85 control groups of Glossina palpalis. Various measures of productivity are discussed together with the problem of how to make predictions of the productivity of a colony when only data for a few age groups are available. Another investigation concerns which life table parameters have the largest influence on the growth rate. (author)

74

Experimental methods in neuroscience: an undergraduate neuroscience laboratory course for teaching ethical issues, laboratory techniques, experimental design, and analysis.  

Science.gov (United States)

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 and 129S1/SvImJ, known to exhibit distinct behavioral traits. The group then employs histological techniques to prepare brain sections for observing neuroanatomical variation between strains (for example, 129S1/SvImJ mice are occasionally acallosal). In the final laboratory exercise, they assay the acetylcholinesterase activity in fore- and hindbrains from each strain. 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. The course concludes with pairs of students conducting self-designed independent projects using the acquired behavioral, histological or neurochemical techniques. Experimental Methods in Neuroscience is proving particularly successful as it is relatively straightforward for students to design interesting experiments, gain experience in neuroscience experimentation without excessive use of animals, gather substantial data sets, and develop skills in scientific report writing and presentation at an early stage in their neuroscience curricula. Furthermore, the course has emerged as a centralizing focus for our neuroscience program and is suitable for transfer to and adaptation by other institutions. PMID:23493933

Hall, Adam C; Harrington, Mary E

2003-01-01

75

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

76

Experimental investigation of the wind turbine blade root flow  

OpenAIRE

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

Akay, B.; Simao Ferreira, Cj; Bussel, Gjw; Tescione, G.

2010-01-01

77

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.)

78

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)

79

Experimental and theoretical investigation of pipe riser clamps  

International Nuclear Information System (INIS)

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

80

Experimental Investigations of Hydrogen Purification by Purging through Metal Hydride  

OpenAIRE

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 nonpoisoning 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 flo...

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

2012-01-01

81

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

OpenAIRE

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 ...

Šafa?ík P.

2013-01-01

82

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

83

Experimental Investigation of the Integral Constant in Steady Flow Conditions  

OpenAIRE

An elaborate experimental system was designed and built in the Hydraulics Laboratory of Civil Engineering Department of Dokuz Eylul University, in order to study the velocity distribution by means of an Ultrasonic Velocity Profiler (UVP) over rough bed at different flow rates. The UVP which has the advantage of providing instantaneous velocity distribution was also used to measure the bed elevations. The shear velocity, u* and the integral constant, Br were calculated from the mean velocity p...

?ükrü Mehmet Güney; Gökçen Bombar

2010-01-01

84

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

85

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

86

EXPERIMENTAL INVESTIGATION OF CRITICAL FUNDAMENTAL ISSUES IN HAZARDOUS WASTE INCINERATION  

Science.gov (United States)

The report gives results of a laboratory-scale program investigating several fundamental issues involved in hazardous waste incineration. The key experiment for each study was the measurement of waste destruction behavior in a sub-scale turbulent spray flame. (1) Atomization Qual...

87

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

88

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

89

Oak Ridge National Laboratory remedial investigation/feasibility study  

International Nuclear Information System (INIS)

The Oak Ridge National Laboratory (ORNL) Remedial Investigation/ Feasibility Study (RI/FS) began in June 1987 to evaluate 13 contaminated waste area groupings (WAGs) to determine the feasibility and benefits of potential remedial action. The RI/FS and any future remedial action at ORNL will be of national significance and will likely lead to developments that will become models for environmental investigations and cleanups. Bechtel National, Inc. and a team of subcontractors will be working with Martin Marietta Energy systems to conduct intensive field investigations to obtain data required to evaluate the WAGs. The RI/F project continued in FY 1988 with project planning and preparation for field activities. Remedial Investigation (RI) Plans were prepared for 10 of the 13 WAGs. These plans were developed with sufficient information to ensure compliance with regulatory requirements, with intensive attention given to environmental, safety, and health protection; waste management; data management; and quality assurance. This paper reports on the progress made during FY 1988 and discusses activities planned for FY 1989

90

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

91

Experimental method for investigating helium effects in irradiated vanadium  

International Nuclear Information System (INIS)

Analyses have been performed which indicate that an effective method for experimentally investigating helium effects in neutron irradiated vanadium base alloys can be developed. The experimental procedure involves only modest modifications to existing procedures currently used for irradiation testing of vanadium-base alloys in the FFTF reactor. Helium is generated in the vanadium alloy by decay of tritium which is either preinjected or generated within the test capsule. Calculations indicate that nearly constant He/dpa ratios of desired magnitude can be attained by proper selection of experimental parameters. The proposed method could have a major impact on the development of vanadium base alloys for fusion reactor applications. 8 refs., 4 figs

92

Experimental methods for laboratory-scale ensilage of lignocellulosic biomass  

International Nuclear Information System (INIS)

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

93

EXPERIMENTAL INVESTIGATION OF AN AIR CHARGED LOW POWERED STIRLING ENGINE  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, an air charged, low powered manufactured ? type Stirling engine was investigated experimentally. Tests were conducted at 800, 900 and 1000 °C hot source temperatures, 1, 1.5, 2, 2.5, 3, 3.5 bars air charge pressure. The variation of engine power depending on the charge pressure and hot source temperature for two different heat transfer area was investigated experimentally. Maximum output power was obtained at 1000 °C and 3 bars charge pressure as 58 W at 441 rpm. Engine speed was reached at 846 rpm without load.

Can ÇINAR

2004-01-01

94

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

95

COMPUTERIZED LABORATORY NOTEBOOK CONCEPT FOR GENETIC TOXICOLOGY EXPERIMENTATION AND TESTING  

Science.gov (United States)

We describe a microcomputer system utilizing the Computerized Laboratory Notebook (CLN) concept developed in our laboratory for the purpose of automating the Battery of Leukocyte Tests (BLT). The BLT was designed to evaluate blood specimens for toxic, immunotoxic, and genotoxic e...

96

Laboratory investigation of dispensing systems for swormlure-4  

International Nuclear Information System (INIS)

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

97

Experimental Investigation of the Integral Constant in Steady Flow Conditions  

Directory of Open Access Journals (Sweden)

Full Text Available An elaborate experimental system was designed and built in the Hydraulics Laboratory of Civil Engineering Department of Dokuz Eylul University, in order to study the velocity distribution by means of an Ultrasonic Velocity Profiler (UVP over rough bed at different flow rates. The UVP which has the advantage of providing instantaneous velocity distribution was also used to measure the bed elevations. The shear velocity, u* and the integral constant, Br were calculated from the mean velocity profiles by applying the Clauser Method and compared with those given in the relevant literature.

?ükrü Mehmet Güney

2010-02-01

98

Theoretical and Experimental Investigation on SMA Superelastic Springs  

Science.gov (United States)

The mechanical behavior of superelastic springs is investigated in this study. The goal is to evaluate the device response and to exploit the material superelastic behavior, main concerns being material and geometrical response nonlinearity. The investigation is made of two parts, i.e., an experimental campaign and a numerical model proposal. Experimental tests have been performed on superelastic SMA coil springs considering load history in tension and compression for three different spring geometrical configurations. Tested specimens experience a maximum elongation larger than the original spring axis length. The response is not symmetric and under compression it is affected by buckling instability. Nevertheless, experimental results show a very good superelastic behavior with no damage and with negligible residual displacements. Numerical analyses have been performed to reproduce the experimental campaign results. A simple finite element model is proposed. Experimental and numerical result agreement is very good. The numerical model turns out to be a powerful design tool even for the very complex geometrical and material nonlinear conditions under investigation. Hence, it is proposed as a useful tool for spring design validation and response prediction.

Attanasi, Gabriele; Auricchio, Ferdinando; Urbano, Marco

2011-07-01

99

Numerical and experimental investigation of bump foil mechanical behaviour  

DEFF Research Database (Denmark)

Corrugated foils are utilized in air foil bearings to introduce compliance and damping thus accurate mathematical predictions are important. A corrugated foil behaviour is investigated experimentally as well as theoretically. The experimental investigation is performed by compressing the foil, between two parallel surfaces, both statically and dynamically to obtain hysteresis curves. The theoretical analysis is based on a two dimensional quasi static FE model, including geometrical non-linearities and Coulomb friction in the contact points and neglects the foil mass. A method for implementing the friction is suggested. Hysteresis curves obtained via the FE model are compared to the experimental results obtained. Good agreement is observed in the low frequency range and discrepancies for higher frequencies are thoroughly discussed.

Larsen, Jon Steffen; Cerda Varela, Alejandro Javier

2014-01-01

100

Emotional Arousal of Beginning Physics Teachers during Extended Experimental Investigations  

Science.gov (United States)

Teachers often have difficulty implementing inquiry-based activities, leading to the arousal of negative emotions. In this multicase study of beginning physics teachers in Australia, we were interested in the extent to which their expectations were realized and how their classroom experiences while implementing extended experimental investigations

Ritchie, Stephen M.; Tobin, Kenneth; Sandhu, Maryam; Sandhu, Satwant; Henderson, Senka; Roth, Wolff-Michael

2013-01-01

101

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

102

Laboratory Investigations With C-Fern(TM) (Ceratopteris richardii)  

Science.gov (United States)

This series of laboratory exercises can be used to enhance existing labs focused on various aspects of plant biology, or to develop new laboratory-based courses at the undergraduate level. It includes a general description of the biology of the model organism used, as well as extensive detailed laboratory exercise instructions for studies in plant development, sex determination in plants, ecology, and genetics.

Thomas R. Warne (University of Tennessee; )

1998-01-01

103

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

104

An experimental investigation of the occupied volume in polymers  

International Nuclear Information System (INIS)

In spite of a great deal of measurements concerning the relative free volume in polymers, the 'occupied volume' remained, up to the present, a concept not subjected to experimental investigations. However, the various theories on the free volume more or less explicitly refer to different, possible definitions of the occupied volume, in particular to its thermal behaviour. In the present work it is shown that it is possible to get information on the occupied volume by coupling positron annihilation lifetime spectroscopy and specific volume measurements; furthermore, some experimental data are discussed and compared to theoretical predictions. (orig.)

105

Experimental Investigation Of Polymeric Compound Cross Section Springs  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents an experimental investigation of the characteristic of the compound cross section springs on models made from polymeric materials (organic glass. Two constructive variants of the compound spring sections were specified with the help of criteria of similarity. The criterion of similarity of natural and model springs was determined by the simulation method at particular spring deflection. The problem of simulation was brought to accurate determination of the magnitudes that characterize the physical and mechanical properties of materials for natural and model springs. It was experimentally proved that the use of the proposed new type of springs significantly increases the spring stiffness.

Mayas Al-Mahasne

2007-01-01

106

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

2015-02-01

107

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.)

108

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

109

Experimental investigation on an inherently actuated passive injection and depressurization system  

International Nuclear Information System (INIS)

ANSALDO has conceived an inherently actuated Passive Injection and Depressurization System (PIDS) to be used in Nuclear Power Plants (NPP). The adoption of the PIDS would allow to enhance the reliability of the Safety Systems, with the additional advantage of a simplification of the NPP current designs. Due to the innovative concept of this system, an experimental investigation has been performed at SIET Laboratory aimed at exploring the physical phenomena governing the behaviour of the system, with the basic goal to demonstrate the concept viability. After a brief description of the PIDS concept, the paper presents the experimental tests matrix and some results. The obtained experimental data confirm the validity of the concept, justifying and encouraging the continuation of the activities and calling for a further development and the execution of related experimental activities. (author). 10 figs, 2 tabs

110

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

111

- 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

112

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

113

Experimental and theoretical investigation of high gradient acceleration  

International Nuclear Information System (INIS)

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

114

Experimental Investigation on Selective Laser Melting of Glass  

Science.gov (United States)

Although laser-based Additive Manufacturing (AM) processes have been investigated extensively for use with different materials, fabrication of 3D glass objects using Selective Laser Melting (SLM) technology is not well developed even though it has many applications. As such an experimental investigation on the process parameters of glass powder using SLM process was conducted and the results are summarized in this paper. Multiple 3D objects were fabricated and analyzed. Lastly Scanning Electron Microcopy (SEM) of the manufactured objects as well as effect of process parameters on dimensional accuracy, surface quality, and the density of the fabricated parts are presented in this paper.

Fateri, Miranda; Gebhardt, Andreas; Thuemmler, Stefan; Thurn, Laura

115

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.)

116

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

117

Experimental and Numerical Investigations of Friction Rings Damping of Blisks  

OpenAIRE

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

Laxalde, Denis; Gibert, Claude; Thouverez, Fabrice

2008-01-01

118

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

119

Experimental investigations of a helical antenna for exciting Alfven waves  

International Nuclear Information System (INIS)

A new coupler for exciting Alfven waves was experimentally investigated. The coupler, which consists of four symmetric helical straps wound around the vacuum vessel, is driven by a four-phase rf source. It has been determined that this coupler excites waves that vary azimuthally as e/sup jm theta/, where m = +-1. The coupler exhibits a strong propagation directionality and is capable of launching waves whose wavelength differs considerably from its own

120

Experimental investigation on the performance of a lithium chloride wheel  

OpenAIRE

This work has investigated the influence of change in operation conditions on the performance of a Lithium Chloride (LiCl) wheel. A rigorous experimental rig that facilitates the measurement of temperature, pressure, pressure drop, relative humidity, airflow rate and rotational speed is used. The measurements covered balanced flow at a wide range of rotational speeds (0 - 9.8 rpm), regeneration temperatures (50-70°C), airflow rates (280-540 kg/h) and relative humidities (30-65%) at amb...

Rabah A.A.

2012-01-01

121

Experimental and Numerical Investigation of 2D Sloshing with Slamming  

OpenAIRE

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

Colagrossi, Andrea; Lugni, Claudio; Greco, Marilena; Faltinsen, Odd

2004-01-01

122

Experimental investigation of the elasticity of the human diaphragm  

OpenAIRE

Abstract Background Traumatic diaphragmatic ruptures affect mainly the left side. In an experimental study in human corpses we examined the stretch behaviour of the left and right diaphragmatic halves. Methods In a total of 8 male and 8 female corpses each diaphragmatic half was divided into 4 different segments. Each segments stretch behaviour was investigated. In steps of 2 N the stretch was increased up to 24 N. Results In the female the left diaphragm showed a stronger elasticity compared...

Kaemmer Daniel; Prescher Andreas; Hohl Christian; Steinau Gerhard; Böhm Gabriele

2010-01-01

123

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

124

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

125

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

126

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

127

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

128

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.

129

Experimental investigation of pebble beds thermal hydraulic characteristics  

International Nuclear Information System (INIS)

The purpose of this paper is to present the results of the experimental investigation of the thermal hydraulic characteristics for two types of test sections-thin annular pebble beds (i.e. spheres dumped in thin annular slots) and pebble beds placed between cylinders. The experimental results of heat transfer from the spheres and from a cylinder, as well as hydraulic drag for both types of test sections are presented in this paper. The results of performed experiments in the case of thin annular pebble beds demonstrated that maximum heat transfer and hydraulic drag is at the relative width of the annular slot K equal to 1.07 and 1.75 of spheres diameter. The heat transfer in internal layers at these values of K is equal to the heat transfer in the internal layers of large (unlimited) rhombic packing. The results of the experimental investigation of pebble beds between cylinders demonstrated that the randomly arranged pebble bed is preferable to the regular rhombic structure from the point of view of design simplicity, heat transfer from the cylinder and drag coefficient

130

Experimental Investigation into Electrical Discharge Machining of Stainless Steel 304  

Directory of Open Access Journals (Sweden)

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

M.M. Rahman

2011-01-01

131

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

132

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.

133

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)

134

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

135

Argumentation and science teaching: an experimental activity in the physics didactical laboratory at high school level  

Directory of Open Access Journals (Sweden)

Full Text Available This paper discuss the high school students´ argumentation. We aim to identify the goal of empirical data for students´ learning when they’re working in small groups in the didactical laboratory. We studied a laboratory in which the students construct arguments to answer questions about the experimental activity. The analysis show that design of the didactical situation and the empirical data are important to make sense in laboratory activity.

Carlos Eduardo Porto Villani

2003-08-01

136

Making controlled experimentation more informative in inquiry investigations  

Science.gov (United States)

This dissertation incorporates three studies that examine how the design of inquiry based science instruction, dynamic visualizations, and guidance for experimentation contribute to physics students' understanding of science. I designed a week-long, technology-enhanced inquiry module on car collisions that logs students' interactions with a visualization. Students studied the module and responded to pretests, posttests, and embedded prompts that assessed students' understanding of motion graphs and collisions. In Study 1, students (N=148) made large, significant overall pretest to posttest gains. Regression models showed that the propensity for students to conduct controlled trials was the strongest predictor of learning when controlling for prior knowledge and other experimentation measures. Successful learners employed a goal-directed experimentation approach that connected their experimentation strategy to content knowledge. Study 2 investigated the effect of limiting students' experimentation on their planning, strategies, and learning outcomes. Students (N=58) made large, significant overall pretest to posttest gains. Students constrained to twelve trials isolated variables in their experiments better than the unconstrained students. However, the constrained students significantly underperformed the unconstrained students on the module assessments, indicating that isolating variables during experimentation did not lead to improved learning outcomes. In Study 3, students (N=166) were assigned to conditions that prompted them either to isolate or compare variables. Both groups made moderate, significant pretest to posttest gains. Students in the compare treatment used more diverse experimentation strategies than students in the isolate treatment. Compare students made nuanced interpretations of collision events based on threshold values. Case studies illustrate how comparing rather than isolating variables helped students use wide-ranging strategies to reach complex insights. The findings illustrate how students can benefit from experimentation strategies that do not isolate variables. Spontaneous exploration can help students test new questions that arise from unexpected results, informing the design of controlled tests that better reveal subtle characteristics of the variables. Guidance that encourages students to compare rather than isolate variables may have important benefits, such as prompting students to search for distinctions among the variables. The findings have important implications for the design of inquiry-based science instruction.

McElhaney, Kevin Wei Hong

137

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

International Nuclear Information System (INIS)

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

138

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

139

Experimental Investigation and Analysis of an Annular Pogo Accumulator  

Science.gov (United States)

An experimental investigation was conducted on a scaled annular pogo accumulator for the Ares I Upper Stage. The test article was representative of the LO2 feedline and preliminary accumulator design, and included multiple designs of a perforated ring connecting the accumulator to the core feedline flow. The system was pulse tested in water over a range of pulse frequency and flow rates. Time dependent measurements of pressure at various locations in the test article were used to extract system compliance, inertance, and resistance. Preliminary results indicated a significant deviation from standard orifice flow theory and suggest a strong dependence on feedline average velocity. In addition, several CFD analyses were conducted to investigate the details of the time variant flow field. Both two-dimensional and three-dimensional simulations were performed with time varying boundary conditions used to represent system pulsing. The CFD results compared well with the sub-scale results and demonstrated the influence of feedline average velocity on the flow into and out of the accumulator. This paper presents updated results of the investigation including a parametric design space for determining resistance characteristics. Using the updated experimental results a new scaling relationship has been defined for shear flow over a cavity. A comparison of sub-scale and full scale CFD simulations provided early verification of the scaling of the fluid flowfield and resistance characteristics.

Peugeot, John; Schwarz, Jordan; Yang, H. Q.; Zoladz, Tom

2011-01-01

140

Exploring dynamic relationships using STELLA (structural thinking experimental learning laboratory with animation)  

Energy Technology Data Exchange (ETDEWEB)

Understanding qualitative and quantitative models is central to much of the activity of a geoscientists. Often such models are portrayed as sticks and boxes in the literature and a verbal description of the mathematics underlying the model is presented to the reader. Such a presentation does not facilitate understanding and does not encourage use of the model to solve a problem or expand an investigation. STELLA (structural thinking experimental learning laboratory with animation) is a software package written for the Macintosh family of microcomputers, that facilitates the construction of dynamic models and encourages playing the what-if game that instructors and managers are fond of promoting. Two examples from the literature are used to illustrate this application.

Butler, J.C. (Univ. of Houston, TX (USA))

1988-11-01

141

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

142

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.)

143

Experimental investigation of effects of external loads on erosive wear  

OpenAIRE

Purpose: The purpose of the paper is to investigate effects of external loads on erosive wear.Design/methodology/approach: In this experimental study, specimens were placed on specially designed a specimen holder and then, external tensile loads corresponding to 0%, 20%, 40% and 60% of the specimen’s yield strength were applied on the specimens. For every load step, the specimens were subjected to 15º, 30º, 45º, 60º, 75º and 90º of erodent impact angles. At the end of the tests, effec...

Imrek, H.; Bagci, M.; Khalfan, O. M.

2009-01-01

144

Numerical and experimental investigation into the aerodynamics of dragonfly flight.  

Science.gov (United States)

Dragonflies have a unique feature in that they drive two pairs of wings independently and modulate the phase delay between them during different modes of flight. To investigate the role of fore-hind wing interactions, we developed a computational tool to simulate flows around multiple wings. We also performed an experiment on tethered dragonflies in order to measure the 3D wing motions and vertical forces. In this talk we report on the comparison of the computed and experimental forces, wing inertia and fluid forces, the passive mechanism of wing rotation, and the effect of fore-hind wing interactions.

Russell, David; Wang, Z. Jane

2004-11-01

145

Experimental investigation of system effects in stressed-skin elements  

DEFF Research Database (Denmark)

What kind of behaviour can be expected from stressed-skin elements at failure? To answer this question was a primary objective of the experimental investigation presented in this report. Systems of 3 roof units, each made of 5 parallel beams, have been tested for load-carrying capacity and behaviour at failure. Test results are compared with analytical calculations estimating the load-bearing capacity from predicted bending strength of each beam used in the system. The test results show that failure of one beam does not necessarily lead to failure of the whole system. This is an important issue in studies of system effects.

Dela Stang, B.; Isaksson, T.

2002-01-01

146

Experimental investigation of cyclic thermomechanical deformation in torsion  

Science.gov (United States)

An investigation of thermomechanical testing and deformation behavior of tubular specimens under torsional loading is described. Experimental issues concerning test accuracy and control specific to thermomechanical loadings under a torsional regime are discussed. A series of shear strain-controlled tests involving the nickel-base superalloy Hastelloy X were performed with various temperature excursions and compared to similar thermomechanical uniaxial tests. The concept and use of second invariants of the deviatoric stress and strain tensors as a means of comparing uniaxial and torsional specimens is also briefly presented and discussed in light of previous thermomechanical tests conducted under uniaxial conditions.

Ellis, John R.; Castelli, Michael G.; Bakis, Charles E.

1992-01-01

147

Experimental investigation of long period grating working in transition mode  

Science.gov (United States)

An experimental investigation of the transition modes of long period gratings (LPG) is reported. Coating LPGs with a material of high refractive index causes a reorganization of the cladding modes, leading to a substantial increase in sensitivity to changes in the surrounding refractive index (SRI). The thickness of polystyrene coatings on optical fibers, applied by dip-coating, was measured by scanning electron microscopy. The maximum sensitivity and corresponding SRI of each coating thickness was then determined by analyzing the attenuation bands in the transmission spectrum.

Melo, Luis; Burton, Geoff; Warwick, Stephen; Wild, Peter

2014-05-01

148

A review of published quantitative experimental studies on factors affecting laboratory fume hood performance.  

Science.gov (United States)

This study attempted to identify the important factors that affect the performance of a laboratory fume hood and the relationship between the factors and hood performance under various conditions by analyzing and generalizing the results from other studies that quantitatively investigated fume hood performance. A literature search identified 43 studies that were published from 1966 to 2006. For each of those studies, information on the type of test methods used, the factors investigated, and the findings were recorded and summarized. Among the 43 quantitative experimental studies, 21 comparable studies were selected, and then a meta-analysis of the comparable studies was conducted. The exposure concentration variable from the resulting 617 independent test conditions was dichotomized into acceptable or unacceptable using the control level of 0.1 ppm tracer gas. Regression analysis using Cox proportional hazards models provided hood failure ratios for potential exposure determinants. The variables that were found to be statistically significant were the presence of a mannequin/human subject, the distance between a source and breathing zone, and the height of sash opening. In summary, performance of laboratory fume hoods was affected mainly by the presence of a mannequin/human subject, distance between a source and breathing zone, and height of sash opening. Presence of a mannequin/human subject in front of the hood adversely affects hood performance. Worker exposures to air contaminants can be greatly reduced by increasing the distance between the contaminant source and breathing zone and by reducing the height of sash opening. Many other factors can also affect hood performance. Checking face velocity by itself is unlikely to be sufficient in evaluating hood performance properly. An evaluation of the performance of a laboratory fume hood should be performed with a human subject or a mannequin in front of the hood and should address the effects of the activities performed by a hood user. PMID:18780237

Ahn, Kwangseog; Woskie, Susan; DiBerardinis, Louis; Ellenbecker, Michael

2008-11-01

149

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

150

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.

151

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

152

The Monotonicity Puzzle: An Experimental Investigation of Incentive Structures  

Directory of Open Access Journals (Sweden)

Full Text Available Non-monotone incentive structures, which - according to theory - are able to induce optimal behavior, are often regarded as empirically less relevant for labor relationships. We compare the performance of a theoretically optimal non-monotone contract with a monotone one under controlled laboratory conditions. Implementing some features relevant to real-world employment relationships, our paper demonstrates that, in fact, the frequency of income-maximizing decisions made by agents is higher under the monotone contract. Although this observed behavior does not change the superiority of the non-monotone contract for principals, they do not choose this contract type in a significant way. This is what we call the monotonicity puzzle. Detailed investigations of decisions provide a clue for solving the puzzle and a possible explanation for the popularity of monotone contracts.

Jeannette Brosig

2010-05-01

153

An Experimental Investigation of the Scaling of Columnar Joints  

CERN Document Server

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 joints. This theory explains the order of magnitude difference in scales between jointing in lavas and in starches. We investigated the scaling of average columnar cross-sectional areas due to the evaporation rate, the analog of the cooling rate of igneous columnar joints. We measured column areas in experiments where the evaporation rate depended on lamp height and time, in experiments where the evaporation rate was fixed using feedback methods, and in experiments where gelatin was added to vary the rheology of the starch. Our results suggest...

Goehring, L; Morris, S; Goehring, Lucas; Lin, Zhenqun; Morris, Stephen

2006-01-01

154

Experimental investigation of the permeability for unconsolidated porous media  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-07-01

155

Experimental investigation of a simulated LOX injector flow field  

Science.gov (United States)

Current development of liquid oxidizer injectors for liquid rocket engines is highly dependent upon experimental investigations of the two-phase liquid oxidizer/gaseous fuel injection plume characteristics. This paper describes an effort to increase the applicability of optical diagnostic approaches to such flow fields find includes an innovative approach for interpreting laser-induced fluorescence signals from axisymmetric two-phase flows. The usefulness of both laser-induced fluorescence and surface scattering techniques are explored herein. The flow field selected for this investigation is an oxidizer-swirled, coaxial flow produced using an injector design under consideration for use in the Space Transportation Main Engine (STME). The liquid oxygen (LOX) flow through this injector is simulated using water. Photographs of laser-induced fluorescence and particle scattering and measured profiles of the mass distribution in this flow field are presented and discussed herein.

Hartfield, Roy J., Jr.; Eskridge, Richard

1993-01-01

156

Experimental investigation of effects of external loads on erosive wear  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The purpose of the paper is to investigate effects of external loads on erosive wear.Design/methodology/approach: In this experimental study, specimens were placed on specially designed a specimen holder and then, external tensile loads corresponding to 0%, 20%, 40% and 60% of the specimen’s yield strength were applied on the specimens. For every load step, the specimens were subjected to 15º, 30º, 45º, 60º, 75º and 90º of erodent impact angles. At the end of the tests, effects of external loads and impingement angles on erosive wear were studied. In the experimental set, dry and compressed air was used to impinge erodents onto the test specimens and subsequent wear was investigated. During the tests, the impingement angles were adjusted by turning the specimen holder around its axis. Erodent particles used were SAE G40 having internal uniform martensitic structure and angular geometry. Determination of erodents speed was achieved with the help of the Rotating Double Disc Method. The speed used in the tests was 30 m/s.Findings: At the end of the tests, erosive wear rates were obtained as functions of stresses and impingement angles. Graphs showing variations of erosive wear rates for load values obtained against every impingement angle and yield stress were drawn. Critical impingement angle and load values at which maximum erosion rate was obtained were determined.Research limitations/implications: In researches made on erosive wears so far; there are only few studies dealing with the effects of external loads on the specimens subjected to erosive wear. By considering that stresses may affect the erosive wear, the stress state around contact area as well as material properties, this experimental study has thus, investigated likely effects of stresses on the erosive wear. With the help of the designed special specimen holder, the specimens were subjected to tensile stresses that are lower than the yield strength of the material and then the erosive wear was investigated.Originality/value: The investigations of effects of external loads on erosive wear.

H. Imrek

2009-01-01

157

Experimental Investigation of a High Pressure Ratio Aspirated Fan Stage  

Science.gov (United States)

The experimental investigation of an aspirated fan stage designed to achieve a pressure ratio of 3.4:1 at 1500 ft/sec is presented in this paper. The low-energy viscous flow is aspirated from diffusion-limiting locations on the blades and flowpath surfaces of the stage, enabling a very high pressure ratio to be achieved in a single stage. The fan stage performance was mapped at various operating speeds from choke to stall in a compressor facility at fully simulated engine conditions. The experimentally determined stage performance, in terms of pressure ratio and corresponding inlet mass flow rate, was found to be in good agreement with the three-dimensional viscous computational prediction, and in turn close to the design intent. Stage pressure ratios exceeding 3:1 were achieved at design speed, with an aspiration flow fraction of 3.5 percent of the stage inlet mass flow. The experimental performance of the stage at various operating conditions, including detailed flowfield measurements, are presented and discussed in the context of the computational analyses. The sensitivity of the stage performance and operability to reduced aspiration flow rates at design and off design conditions are also discussed.

Merchant, Ali; Kerrebrock, Jack L.; Adamczyk, John J.; Braunscheidel, Edward

2004-01-01

158

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

159

The Experimental Manpower Laboratory for Corrections: Progress Report on Phase V, March Through June, 1974.  

Science.gov (United States)

The Experimental Manpower Laboratory for Corrections has conducted continuous experimental studies in offender rehabilitation since the lab was created in 1968. The opportunity to incorporate the findings and products from previous studies by developing a behavioral management model was provided in March 1973, when the lab began its Mount Meigs…

Rehabilitation Research Foundation, Montgomery, AL.

160

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

International Nuclear Information System (INIS)

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

161

Experimental investigation of buried tritium in plant and animal tissues  

Energy Technology Data Exchange (ETDEWEB)

Buried exchangeable tritium appears as part of organically bound tritium (OBT) in the traditional experimental determination of OBT. Since buried tritium quickly exchanges with hydrogen atoms in the body following ingestion, assuming that it is part of OBT rather than part of tritiated water (HTO) could result in a significant overestimate of the ingestion dose. This paper documents an experimental investigation into the existence, amount and significance of buried tritium in plant and fish samples. OBT concentrations in the samples were determined in the traditional way and also following denaturing with five chemical solutions that break down large molecules and expose buried tritium to exchange with free hydrogen atoms. A comparison of the OBT concentrations before and after denaturing, together with the concentration of HTO in the supernatant obtained after denaturing, suggests that buried OBT may exist but makes up less than 5% of the OBT concentration in plants and at most 20% of the OBT concentration in fish. The effects of rinse time and rinse water volumes were investigated to optimize the removal of exchangeable OBT from the samples. (authors)

Kim, S. B.; Workman, W. J. G.; Davis, P. A. [AECL, Chalk River Laboratories, Environmental Technologies Branch, Chalk River, ON K0J 1J0 (Canada)

2008-07-15

162

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

163

Optical actuation of silicon cantilevers: modelling and experimental investigation  

Science.gov (United States)

This paper reports on the modeling and experimental investigation of optical excitation of silicon cantilevers. In this work, the silicon cantilevers fabricated have dimensions with width of 15 ?m, thickness of 0.26 ?m, and variable length from 50 to 120 ?m. In order to investigate the effect of the laser modulation frequency and position on the temperature at the anchor edge and displacements at the tip of cantilevers, a transient thermal ANSYS simulation and a steady-state static thermal mechanical ANSYS simulation were undertaken using a structure consisting of silicon device layer, SiO2 sacrificial layer and silicon substrate. The dynamic properties of silicon cantilevers were undertaken by a series of experiments. The period optical driving signal with controlled modulation amplitude was provided by a 405 nm diode laser with a 2.9 ?W/?m2 laser power and variable frequencies. The laser spot was located through the longitude direction of silicon cantilevers. In factor, simulation results well matched with experimental observation, including: 1) for untreated silicon cantilevers, the maximum of displacement is observed when the laser beam was located half a diameter way from the anchor on the silicon suspended cantilever side; 2) for the both cantilevers, maximum displacement occurs when the optical actuation frequency is equal to the resonant frequency of cantilevers. Understanding the optical excitation on silicon cantilevers, as waveguides, can potentially increase sensing detection sensitivity (ratio of transmission to cantilever deflection).

Jiang, Fei; Keating, Adrian; Martyuink, Mariusz; Silva, Dilusha; Faraone, Lorenzo; Dell, John M.

2013-05-01

164

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

165

Experimental investigation of buried tritium in plant and animal tissues  

International Nuclear Information System (INIS)

Buried exchangeable tritium appears as part of organically bound tritium (OBT) in the traditional experimental determination of OBT. Since buried tritium quickly exchanges with hydrogen atoms in the body following ingestion, assuming that it is part of OBT rather than part of tritiated water (HTO) could result in a significant overestimate of the ingestion dose. This paper documents an experimental investigation into the existence, amount and significance of buried tritium in plant and fish samples. OBT concentrations in the samples were determined in the traditional way and also following denaturing with five chemical solutions that break down large molecules and expose buried tritium to exchange with free hydrogen atoms. A comparison of the OBT concentrations before and after denaturing, together with the concentration of HTO in the supernatant obtained after denaturing, suggests that buried OBT may exist but makes up less than 5% of the OBT concentration in plants and at most 20% of the OBT concentration in fish. The effects of rinse time and rinse water volumes were investigated to optimize the removal of exchangeable OBT from the samples. (authors)

166

Experimental investigation of turbulent mixing by Rayleigh-Taylor instability  

International Nuclear Information System (INIS)

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

167

Laboratory experimental studies of seismic scattering from fractures  

Science.gov (United States)

Laboratory acoustic measurements are performed with Lucite fracture models to understand the scattering characteristics of a seismic wave in a fracture zone. The fracture models include single, dual, and multiple fracture zones with varying fracture apertures, height, and spacing. Fractures are created by both very fine saw cuts and laser-etching. A vertical P-wave source is used with vertical (P) and horizontal (S) receivers to measure the reflected and scattered wavefield as a function of offset and azimuth relative to the fracture orientation. The amplitude of the arrival generated from the fracture tips is proportional to the fracture aperture. Comparison of traces from a single fracture and a dual fracture model indicates that multiple scattering is an important component of the scattered wave signal in fracture systems. In the fracture zone models, the PP and PS scattered wave energy varies azimuthally providing multiple methods for fracture orientation estimation. In particular, PS scattering on the transverse component is a maximum at 45°, while the PS inline component shows a systematic increase in amplitude as the azimuth approaches 90°. Total scattered wave energy is also observed to vary with changes in fracture aperture and height providing a possible means to estimate fracture zone flow capacity from seismic data.

Zhu, Zhenya; Burns, Daniel R.; Brown, Steve; Fehler, Michael

2015-04-01

168

Mineralogical-geochemical effects during geological storage of CO2 : experimental investigations and geochemical modeling  

OpenAIRE

In order to analyze mineralogical-geochemical changes occurring in whole rock reservoir samples (Stuttgart Formation) from the Ketzin pilot CO2 storage site, Brandenburg/Germany as well as to investigate single fluid-mineral reactions laboratory experiments and geochemical modeling were performed. The whole rock core samples of the Stuttgart Formation were exposed to synthetic brine and pure CO2 at experimental P-T conditions and run durations of 5.5 MPa/40 °C/40 months for sandstone and 7.5...

Sebastian Fischer

2013-01-01

169

Experimental Investigation of Pool Boiling Heat Transfer Enhancement in Microgravity in the Presence of Electric Fields  

Science.gov (United States)

The research carried out in the Heat Transfer Laboratory of the Johns Hopkins University was motivated by previous studies indicating that in terrestrial applications nucleate boiling heat transfer can be increased by a factor of 50 when compared to values obtained for the same system without electric fields. Imposing an external electric field holds the promise to improve pool boiling heat transfer in low gravity, since a phase separation force other than gravity is introduced. The influence of electric fields on bubble formation has been investigated both experimentally and theoretically.

Herman, C.

2000-01-01

170

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

171

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

172

ASSESSMENT OF BACK PAIN: Part IV - Laboratory Investigations  

OpenAIRE

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

La Harpe, David

1994-01-01

173

Wheat-germ agglutination of Neisseria gonorrhoeae. A laboratory investigation.  

OpenAIRE

Wheat-germ agglutination (WGA) was used to identify 168 strains of Neisseria gonorrhoeae and 105 strains of other Neisseria species in a routine laboratory. About one-third of the meningococci reacted with the lectin and titres with some organisms varied on repeat testing. The technique is regarded as unreliable for the identification of Neisseria species.

Curtis, G. D.; Slack, M. P.

1981-01-01

174

An Adaptable Investigative Graduate Laboratory Course for Teaching Protein Purification  

Science.gov (United States)

This adaptable graduate laboratory course on protein purification offers students the opportunity to explore a wide range of techniques while allowing the instructor the freedom to incorporate their own personal research interests. The course design involves two sequential purification schemes performed in a single semester. The first part…

Carroll, Christopher W.; Keller, Lani C.

2014-01-01

175

Experimental investigation of dispersion phenomenon in a fractured porous medium  

Directory of Open Access Journals (Sweden)

Full Text Available Dispersion of fluids flowing through porous media is an important phenomenon in miscible displacement. Dispersion causes instability of miscible displacement flooding; therefore, to obtain and maintain the miscibility zone, the porous medium dispersivity should be considered in displacing fluid volume calculation. Many works have been carried out to investigate the dispersion phenomenon in porous media in terms of theory, laboratory experiments and modeling. What is still necessary is to study the effects of presence of fracture in a porous medium on dispersion coefficient or dispersivity. In this work dispersion phenomenon in a fractured porous medium has been investigated through a series of miscible displacement tests on homogeneous sandstone core samples. Tests were repeated on the same core samples with induced fracture in the flow direction. The effects of fracture on miscible displacement flooding have been studied by comparison of the results of dispersion tests in the absence and presence of fracture. In the presence of fracture, breakthrough time reduced and the tail of effluent S-shaped curve smeared. Moreover, the slope of S-shaped curve at 1 pore volume of injected fluid was lower than homogeneous case which means dispersion coefficient increased. The results presented in this work provide an insight to the understanding of dispersion phenomenon for modeling of miscible displacement process through naturally fractured reservoirs.

Ali Sanati

2015-02-01

176

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

Science.gov (United States)

Clinical studies have established a strong benefit from adjuvant mild hyperthermia (HT) to radio- and chemotherapy for many tumor sites, including the head and neck (H&N). The recently developed HYPERcollar allows the application of local radiofrequency HT to tumors in the entire H&N. Treatment quality is optimized using electromagnetic and thermal simulators and, whenever placement risk is tolerable, assessed using invasively placed thermometers. To replace the current invasive procedure, we are investigating whether magnetic resonance (MR) thermometry can be exploited for continuous and 3D thermal dose assessment. In this work, we used our simulation tools to design an MR compatible laboratory prototype applicator. By simulations and measurements, we showed that the redesigned patch antennas are well matched to 50 ? (S11<-10 dB). Simulations also show that, using 300 W input power, a maximum specific absorption rate (SAR) of 100 W kg-1 and a temperature increase of 4.5 °C in 6 min is feasible at the center of a cylindrical fat/muscle phantom. Temperature measurements using the MR scanner confirmed the focused heating capabilities and MR compatibility of the setup. We conclude that the laboratory applicator provides the possibility for experimental assessment of the feasibility of hybrid MR-HT in the H&N region. This versatile design allows rigorous analysis of MR thermometry accuracy in increasingly complex phantoms that mimic patients' anatomies and thermodynamic characteristics.

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

2014-05-01

177

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)

178

Experimental investigation of the Richtmyer-Meshkov instability.  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-09-01

179

[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

180

Experimental investigations in turbulent buoyant jets of sodium  

International Nuclear Information System (INIS)

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

181

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

182

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

183

Experimental Investigation of High Temperature Superconducting Imaging Surface Magnetometry  

International Nuclear Information System (INIS)

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 YBa2Cu3O7-? 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

184

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

185

A review of experimental investigations on blast resistance of structures  

International Nuclear Information System (INIS)

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

186

The optical activity of carvone: A theoretical and experimental investigation  

Science.gov (United States)

The optical rotatory dispersion (ORD) and circular dichroism of the conformationally flexible carvone molecule has been investigated in 17 solvents and compared with results from calculations for the "free" (gas phase) molecule. The G3 method was used to determine the relative energies of the six conformers. The optical rotation of (R)-(-)-carvone at 589 nm was calculated using coupled cluster and density functional methods, including temperature-dependent vibrational corrections. Vibrational corrections are significant and are primarily associated with normal modes involving the stereogenic carbon atom and the carbonyl group, whose n ? ?* excitation plays a significant role in the chiroptical response of carvone. Without the inclusion of vibrational corrections the optical rotation calculated with CCSD and DFT has the opposite sign of experimental data. Calculations of optical rotation performed in solution using the polarizable continuum model were also opposite in sign when compared to that of the experiment.

Lambert, Jason; Compton, R. N.; Crawford, T. Daniel

2012-03-01

187

Experimental Investigations on Pool Boiling CHF of Nano-Fluids  

International Nuclear Information System (INIS)

Pool boiling Critical Heat Flux (CHF) of nanofluids with oxide nanoparticles of TiO2 or Al2O3 was experimentally investigated under atmospheric pressure. The results showed that a dispersion of oxide nanoparticles significantly enhances the CHF over that of pure water. Moreover it was found that nanoparticles were seriously deposited on the heater surface during pool boiling of nanofluids. CHF of pure water on a nanoparticle-deposited surface, which is produced during the boiling of nanofluids, was not less than that of nanofluids. The result reveals that the CHF enhancement of nanofluids is absolutely attributed to modification of the heater surface by the nanoparticle deposition. Then, the nanoparticle-deposited surface was characterized with parameters closely related to pool boiling CHF, such as surface roughness, contact angle, and capillary wicking. Finally, reason of the CHF enhancement of nanofluids is discussed based on the changes of the parameters

188

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)

189

Experimental and computational investigation of lateral gauge response in polycarbonate  

Science.gov (United States)

The shock behaviour of polycarbonate is of interest due to its extensive use in defence applications. Interestingly, embedded lateral manganin stress gauges in polycarbonate have shown gradients behind incident shocks, suggestive of increasing shear strength. However, such gauges are commonly embedded in a central epoxy interlayer. This is an inherently invasive approach. Recently, research has suggested that in such systems interlayer/target impedance may contribute to observed gradients in lateral stress. Here, experimental T-gauge (Vishay Micro-Measurements® type J2M-SS-580SF-025) traces from polycarbonate targets are compared to computational simulations. The effects of gauge environment are investigated by looking at the response of lateral gauges with both standard "glued-joint" and a "dry joint" encapsulation, where no encapsulating medium is employed.

Eliot, Jim; Harris, Ernest Joseph; Hazell, Paul; Appleby-Thomas, Gareth James; Winter, Ron; Wood, David Christopher

2012-03-01

190

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

191

An experimental-differential investigation of cognitive complexity  

Directory of Open Access Journals (Sweden)

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

2009-12-01

192

Experimental Investigation of Software Testing and Reliability Assessment Methods (EISTRAM)  

Energy Technology Data Exchange (ETDEWEB)

The Experimental Investigation of Software Testing and Reliability Assessment Methods (EISTRAM) project builds on experiences from the RESTRAM review project, which pinpointed certain reliability assessment methods as particularly interesting. The focus for the EISTRAM project is the PIE-technique, proposed by Jeffrey Voas, a technique to estimate the sensitivity of programs. PIE is a reverse acronym for Execution, Infection and Propagation, the three stages needed for a code error to produce a program failure. This progress report contains a description of the PIE-technique and the statistical fundament of the technique. It presents a classification of the syntactic mutants, and criteria for the selection of mutants to use in the PIE analysis. Issues concerning implementation of the technique are described, as well as results from using the technique on three test programs. (author)

Gran, Bjoern Axel; Thunem, Harald

1996-07-01

193

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

194

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.)

195

Numerical and experimental investigation of nonswirling and swirling confined jets  

Science.gov (United States)

An investigation of the influence of large scale structures on the flow development for coaxial jets with sudden expansion (with and without swirl) is presented. Both an experimental study and numerical predictions were performed for a configuration corresponding to that considered by Johnson and Bennett and Roback and Johnson. The effects of large scale structures on the swirling and nonswirling flows are documented, in particular their influence on turbulence modeling and the numerical simulation. The ensemble-averaged, time-dependent Navier-Stokes equations are solved by an LBI procedure to predict the turbulent flow field. Effects of artificial dissipation and placement of the upstream boundary in the numerical computation are also discussed.

Brondum, D. C.; Bennett, J. C.; Weinberg, B. C.; Mcdonald, H.

1986-01-01

196

Experimental investigation of the fragmentation of molten metals in water  

International Nuclear Information System (INIS)

Small amounts of molten tin and bismuth were dropped into water to investigate the fragmentation of molten metals.The major parameter of the experimental program was the initial drop temperature but drop mass and drop material were also varied. The pressure signal of the interaction was recorded, high speed motion pictures of the interaction were made, and the metallic debris was collected. The experiments and analysis were patterned after and were intended to be a continuation of work done by Trond Bjornard. Several important additions were made to the experimental apparatus. Specifically they were a hotter furnace to allow a greater range of initial drop temperature, provision of an argon atmosphere during the melting and dropping of the metal sample to prevent excessive oxidation at high temperatures, and modification of the tape recorder to allow a longer time interval to be recorded. An attempt was made to interpret the dwell time in terms of the cooling of the molten drop. Calculations show that, in the case of tin, drops with an initial temperature greater than 6000C will cool to a temperature in the vicinity of 6000C before fragmenting. (U.S.)

197

Experimental investigations of a chimney-dependent solar crop dryer  

Energy Technology Data Exchange (ETDEWEB)

An experimental investigation into the performance of a solar crop dryer with solar chimney and no air preheating is described. Tests were first performed on the cabinet dryer, using a normal chimney. The trials were repeated with a solar chimney. Still with the solar chimney, further trials were carried out with the roof of the drying chamber inclined further to form a tent dryer. The described tests include no-load tests for airflow rate measurements and drying tests, with cassava as the crop. Air velocities, temperatures, ambient relative humidity and the drop in crop moisture contents at different stages of the drying process are also presented. The effects of the various configurations described above on the drying process are deduced and discussed while comparing the experimental results with one another. In addition, the performance of the dryer in relation to other natural convection dryers is discussed. The results show that the solar chimney can increase the airflow rate of a direct-mode dryer especially when it is well designed with the appropriate angle of drying-chamber roof. However, the increase in flow rate only increases the drying rate when the relative humidity (RH) of the ambient air is below a certain mark (60% for cassava). (author)

Afriyie, J.K.; Nazha, M.A.A.; Rajakaruna, H. [School of Engineering and Technology, De Montfort University, Queens Building, The Gateway, Leicester LE1 9BH (United Kingdom); Forson, F.K. [Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana)

2009-01-15

198

Experimental investigation of pyrolysis process of woody biomass mixture  

Science.gov (United States)

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

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

2014-06-01

199

Experimental investigation of the Mg-Al-Ca system  

International Nuclear Information System (INIS)

This work focuses on the experimental investigation of the ternary Mg-Al-Ca system using differential scanning calorimetry (DSC), X-ray diffraction (XRD) and metallographic techniques. DSC has permitted real time measurement of the temperature and enthalpy of the phase transformations. One of the invariant transformations predicted by thermodynamic modeling was verified experimentally and found to occur at 513 oC with composition close to 10.8 at.% Ca, 79.5 at.% Mg and 9.7 at.% Al. Three binary compounds are found to have an extended solid solubility into the ternary system: (Mg2Ca) where Al substitute Mg in the binary compound Mg2Ca (Al2Ca) and (Al3Ca8) where Mg substitute Al in the binary compounds Al2Ca and Al3Ca8, respectively. Two morphologies of eutectic structure were observed in the micrographs and supported by solidification curves; a coarse and fine eutectic microstructures due to the existence of Al2Ca and Mg2Ca, respectively

200

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

201

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

202

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.

203

An Experimental Investigation of Corium Jet Impingement on Structural Material  

Energy Technology Data Exchange (ETDEWEB)

During a severe accident in a nuclear power plant, the erosion of external structures of a reactor vessel by corium jet impingement owing to the failure of the reactor lower head is an important issue because the containment integrity can be seriously threatened. KAERI has proposed an experimental methodology and set up the VESTA (Verification of Ex-vessel corium STAbilization) facility to investigate the interaction of an oxidic jet with an oxidized steel (Fe{sub 2}O{sub 3}) structure containing a small amount of water and verify the existing ablation models. The oxidic jet impingement experiments on the oxidized steel structure containing a small amount of water content in crystalline hydrates were performed, and the ablation depth and rate were compared with the predictions by the existing models. The ablation of the structural material turned out to be governed by the jet convection, and the experimental results were predicted properly by the models. However, the models need to be improved by considering the transient effect of the heat transfer for better predictions, which is left as a future work.

An, Sang Mo; Ha, Kwang Soon; Min, Beong Tae; Hong, Seong Ho; Kim, Hwan Yeol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-10-15

204

Experimental investigation on the performance of a lithium chloride wheel  

Directory of Open Access Journals (Sweden)

Full Text Available This work has investigated the influence of change in operation conditions on the performance of a Lithium Chloride (LiCl wheel. A rigorous experimental rig that facilitates the measurement of temperature, pressure, pressure drop, relative humidity, airflow rate and rotational speed is used. The measurements covered balanced flow at a wide range of rotational speeds (0 - 9.8 rpm, regeneration temperatures (50-70°C, airflow rates (280-540 kg/h and relative humidities (30-65% at ambient condition. The influence of those operation conditions on the wheel sensible effectiveness and coefficient of performance (COP are analyzed. The result revealed that a maximum COP occurs at a rotational speed of 0.2 rpm (12 rph. The results also concluded that Kays and London correlation is sufficient in the prediction of the effectiveness of the LiCl wheel. It represents the experimental data with an average absolute percent deviation (AAPD of 2.16 and a maximum absolute percent deviation (APDmax of about 6.00.

Rabah A.A.

2012-01-01

205

An Experimental Investigation of Corium Jet Impingement on Structural Material  

International Nuclear Information System (INIS)

During a severe accident in a nuclear power plant, the erosion of external structures of a reactor vessel by corium jet impingement owing to the failure of the reactor lower head is an important issue because the containment integrity can be seriously threatened. KAERI has proposed an experimental methodology and set up the VESTA (Verification of Ex-vessel corium STAbilization) facility to investigate the interaction of an oxidic jet with an oxidized steel (Fe2O3) structure containing a small amount of water and verify the existing ablation models. The oxidic jet impingement experiments on the oxidized steel structure containing a small amount of water content in crystalline hydrates were performed, and the ablation depth and rate were compared with the predictions by the existing models. The ablation of the structural material turned out to be governed by the jet convection, and the experimental results were predicted properly by the models. However, the models need to be improved by considering the transient effect of the heat transfer for better predictions, which is left as a future work

206

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

207

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.)

208

Experimental and theoretical investigation of anaerobic fluidized bed biofilm reactors  

Scientific Electronic Library Online (English)

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 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

209

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

210

An Investigative Laboratory Course in Human Physiology Using Computer Technology and Collaborative Writing  

Science.gov (United States)

Active investigative student-directed experiences in laboratory science are being encouraged by national science organizations. A growing body of evidence from classroom assessment supports their effectiveness. This study describes four years of implementation and assessment of an investigative laboratory course in human physiology for 65…

FitzPatrick, Kathleen A.

2004-01-01

211

Leaving patches: An investigation of a laboratory analogue  

OpenAIRE

Five pigeons were trained on a procedure that has been used as a laboratory analogue to natural patch residence. Trials commenced with two responses available. One of these might provide a reinforcer if the patch was a prey patch; the other ended the residence time in the patch and, after a fixed travel time in blackout, produced another patch that might or might not provide a reinforcer. Patch residence also ended, and was followed by the same travel time, after a reinforcer was obtained or ...

Davison, Michael; Mccarthy, Dianne

1994-01-01

212

An experimental investigation of pump as turbine for micro hydro application  

International Nuclear Information System (INIS)

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

213

An experimental investigation of pump as turbine for micro hydro application  

Science.gov (United States)

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

>N Raman, I Hussein,

2013-06-01

214

Experimental investigation of the acceleration of deflagration in wake flow  

International Nuclear Information System (INIS)

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

215

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

216

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

217

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

218

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)

219

Overview of Experimental Investigations for Ares I Launch Vehicle Development  

Science.gov (United States)

Another concern for the vehicle during its design trajectory was the separation of the first stage solid rocket booster from the upper stage component after it had depleted its solid fuel propellant. There has been some concern about the interstage of the first stage from clearing the nozzle of the J2-X engine. A detailed separation aerodynamic wind tunnel investigation was conducted in the AEDC VKF Tunnel A to help to investigate the interaction aerodynamic effects5. A comparison of the separation plane details between the Ares I architecture and the Ares I-X demonstration flight architecture is shown in figure 12. The Ares I design requires a more complex separation sequence and requires better control in order to avoid contact with the nozzle of the upper stage engine. The interstage, which houses the J2-X engine for the Ares I vehicle, must be able to separate cleanly to avoid contact of the J2-X engine. There is only about approximately 18 inches of buffer inside the interstage on each size of the nozzle so this is a challenging controlled separation event. This complex experimental investigation required two separate Ares I models (upper stage and first stage with interstage attached) with independent strain gauge balances installed in each model. It also required the Captive Trajectory System (CTS) that was needed to precisely locate the components in space relative to each other to fill out the planned test matrix. The model setup in the AEDC VKF Tunnel A is shown in figure 13. The CTS remotely positioned the first stage at the required x, y, and z positions and was able to provide interactions within 0.2" of the upper stage. A sample of the axial force on the first stage booster is shown in figure 14. These results, as a function of separation distance between the two stages, are compared to pre-test CFD results. Since this is a very challenging, highly unsteady flow field for CFD to correctly model, the experimental results have been utilized by GN&C discipline to more accurately represent the interaction aerodynamics. In addition to the integrated forces and moments obtained from the test, flow visualization data was obtained from this test in the form of Schlieren photographs, as shown in figure 15, which show the shock structure and interaction effects after the two stages separate during flight. This separation test was crucial in the successful flight test of the Ares I-X vehicle and provided the GN&C discipline with the unpowered proximity aerodynamic effect for a separation of the Ares I vehicle.

Tomek, William G.; Erickson, Gary E.; Pinier, Jeremy T.; Hanke, Jeremy L.

2011-01-01

220

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

221

Laboratory Experimental System for Examination of Acoustic Emission Generated by Partial Discharges  

Directory of Open Access Journals (Sweden)

Full Text Available One of the major causes of transformer failures is dielectric breakdown. Partial discharges cause gradual insulation degradation thus partial discharge activity monitoring provides transformer state insight. This paper gives an overview of common methods for partial discharges detection and source location in transformers, with a special reference to the acoustic method as an noninvasive and interference resistant method suitable for application. For laboratory testing a laboratory experimental system for partial discharge diagnostics using acoustic emission measurement was developed.

I. M. Salom

2013-11-01

222

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

International Nuclear Information System (INIS)

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

223

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

International Nuclear Information System (INIS)

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

224

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)

225

Theoretical and experimental investigations into intermetallic phases containing aluminium  

International Nuclear Information System (INIS)

This thesis is mainly concerned with the structural chemistry of intermetallic compounds consisting of aluminium and one or more electropositive alkali or alkali earth metals, and is divided into a theoretical and an experimental part. The theoretical part represents an attempt to clarify the situation of chemical bonding in such compounds. Thus, the electron-localisation-function (ELF) was calculated for the following row: Al ?CaAl2?SrAl2?BaAl4?CaAl2Si2?Si. ELF permits one to distinguish between metallic bonds in fcc-Al and CaAl2, localised multi-center bonds in BaAl4, two-center bonds in SrAl2 and BaAl4, as well as polarised bonds in CaAl2Si2. The results of linear-muffin-tin-orbital (LMTO) calculations and semiempirical extended-Hueckel (EH) calculations differ only slightly for these compounds. Furthermore, the topological analysis of the scalar fields electron density ?(x,y,z) and ELF(x,y,z) according to Bader were used to define Dirichlet domains for atoms and electrons in the above mentioned compounds. Integration over the electron density within these domains led to the assignment of electron numbers to such domains. These electron numbers define net charges in the case of atomic Dirichlet domains and can be used for classifying chemical bonding when considering electronic Dirichlet domains. The relative stability of three-dimensitive stability of three-dimensional nets formed by gallium or aluminium in intermetallic phases was investigated within the simple tight-binding (TB) Hueckel model. The experimental part of this work includes the synthesis of ternary compounds consisting of Li, EA, and Al (EA = Ca,Sr,Ba) and their characterisation with X-ray structural analysis on single crystals. (author) figs., tabs., 105 refs

226

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)

227

Experimental investigation of hot electrons inside cavity target  

International Nuclear Information System (INIS)

In the interaction of intense laser-plasma, hot electrons, which can preheat the core of the fuel and lower the compression efficiency, are produced by collective processes such as stimulated Raman Scattering (SRS), resonance absorption (RA), two plasma decay (TPD) and ion acoustic decay (IAD). It is very important to study hot electrons experimentally and theoretically. The spectrum and total energy of hard X-rays outside the cavity targets have been measured for many years. In order to correct theoretical model and improve accuracy of calculating the total energy of hot electrons in cavities, it is urgent to identify the traveling direction of hot electrons and the regions of hard X-rays generation. In the experiment reported, specific cavities was designed to investigate the angular distribution of hot electrons in cavity and the region of hard X-ray generation. Experiments were conduced on Shengguang high power laser facility. The cavity target was irradiated by one beam laser (? = 1.06 ?m, EL = 450?550 J, ?? 0.8 ns, IL ?1015 W·cm-2). A ten channel filter fluorescence spectrometer and an array of separate GaAs photoconductor were used to measure the spectra, angular distribution, and total energy of hard X-rays, and the energy of stimulated Raman scattering light was also measured for comparison. From the specific structure of cavities and the experimental results, the following two main results were inferred: two main results were inferred: (1) Most of the hot electrons in cavity are inclined to travel along the direction of laser wave vector, not isotropically. (2) Hard X-rays were mainly produced by Bremsstrahlung effect of hot electrons' collision with gold cavity wall

228

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.

229

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

230

Experimental investigations of the vertically loaded small scale bored piles  

Directory of Open Access Journals (Sweden)

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

Glazachev Anton Olegovich

2014-04-01

231

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

International Nuclear Information System (INIS)

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

232

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

International Nuclear Information System (INIS)

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

233

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 x10-4 and 5.5 x10-6 for the initial uptake coefficient (g0 approx 3 x10-5 at 30 ppbv O3 STP and between 4.8 x10-5 and 2.2 x10-6 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

2002-11-01

234

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

Science.gov (United States)

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

McNeill, James; Hertzberg, Jean; Zhai, Zhiqiang

2010-11-01

235

Experimental Investigation of the NASA Common Research Model  

Science.gov (United States)

An experimental aerodynamic investigation of the NASA Common Research Model has been conducted in the NASA NTF (National Transonic Facility). Data have been obtained at chord Reynolds numbers of 5, 19.8 and 30 million for the WB and WBT0 configurations. Data have also been obtained at a chord Reynolds number of 5 million for the WBNP, WBT+2 and WBT-2 configurations. Force and moment, surface pressure and surface flow visualization data were obtained but only the force and moment data are presented herein. Model deformation measurements, aeroelastic, nacelle/pylon Reynolds number and tail effects have been assessed. The model deformation measurements showed more twist as you go out the wing span, with a break in the high q(sub infinity) data close to CL = 0.6 which is consistent with separation near the tip. Increases in dynamic pressure give an increase in pitching moment and drag and a decrease in lift for the WB and WBT0 configuration at Mach = 0.7, 0.85 and 0.87. The addition of a nacelle/pylon gave an increase in drag, decrease in lift and a less nose down pitching moment around the design lift condition of 0.5. Increases in chord Reynolds number have been found to follow the normal Reynolds number trends except at the 19.8 million low q(sub infinity) cases. The abnormality of the 19.8 million low q(sub infinity) cases is being investigated. The tail effects also follow the expected trends. All of the data shown fall within the 2-sigma limits for repeatability.

Rivers, Melissa B.; Dittberner, Ashley

2010-01-01

236

Laboratory and Theoretical Investigations of a Ring-Capacitor Sensor  

Science.gov (United States)

Ring-capacitor sensors are used widely for real-time estimation of volumetric soil water content ' from measured resonant frequency fr which is affected by the complex bulk soil permittivity ' = '’ + i'’’. However, the relationship fr(') requires improved investigation in terms of the dependence of ...

237

Experimental investigation and mechanistic modelling of dilute bubbly bulk boiling  

Energy Technology Data Exchange (ETDEWEB)

During evaporation the geometric shape of the vapour is not described using thermodynamics. In bubbly flows the bubble shape is considered spheric with small diameters and changing into various shapes upon growth. The heat and mass transfer happens at the interfacial area. The forces acting on the bubbles depend on the bubble diameter and shape. In this work the prediction of the bubble diameter and/or bubble number density in bulk boiling was considered outside the vicinity of the heat input area. Thus the boiling effects that happened inside the nearly saturated bulk were under investigation. This situation is relevant for nuclear safety analysis concerning a stagnant coolant in the spent fuel pool. In this research project a new experimental set-up to investigate was built. The experimental set-up consists of an instrumented, partly transparent, high and slender boiling container for visual observation. The direct visual observation of the boiling phenomena is necessary for the identification of basic mechanisms, which should be incorporated in the simulation model. The boiling process has been recorded by means of video images and subsequently was evaluated by digital image processing methods, and by that data concerning the characteristics of the boiling process were generated for the model development and validation. Mechanistic modelling is based on the derivation of relevant mechanisms concluded from observation, which is in line with physical knowledge. In this context two mechanisms were identified; the growth/-shrink mechanism (GSM) of the vapour bubbles and sudden increases of the bubble number density. The GSM was implemented into the CFD-Code ANSYS-CFX using the CFX Expression Language (CEL) by calculation of the internal bubble pressure using the Young-Laplace-Equation. This way a hysteresis is realised as smaller bubbles have an increased internal pressure. The sudden increases of the bubble number density are explainable by liquid super-heating. The liquid super-heating is only possible if the heat and mass transfer between the phases is slower than the saturation temperature reduction by hydrostatic pressure decreases along the height of the boiling container or due to bubble growth. By activation of the so far inactive micro-bubbles in the liquid bulk volume the bubble number density quickly increases. This effect is modelled by an algebraic function that uses a constant bubble number density in the vicinity of the saturation temperature and applies an exponentially increased bubble number density depending on the liquid super-heating. Based on modelling a local and variable bubble number density numerical flow simulations were performed. The simulations showed that this approach is a suitable model to describe the mechanisms found in the experiments. Model parameters were determined and verified by correlation with the experimental data.

Kutnjak, Josip

2013-06-27

238

Numerical and experimental investigations on unsteady aerodynamics of flapping wings  

Science.gov (United States)

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

Yu, Meilin

239

Experimental study of the subtalar joint axis: preliminary investigation.  

Science.gov (United States)

An experimental study of the subtalar joint has been conducted with the aim of establishing its axis of movement as well as analysing the associated movement. For description of the axis, CT data for five positions of a single foot were reconstructed using a 3D programme, the 3D data was processed by Patran software. Measures of angular displacements were made from three amputated feet placed in a specially constructed foot frame. Four instantaneous axes of movement could be defined. Calculation of displacements showed an important rolling of the calcaneus (45 degrees). Tacking was evident in inversion, with an opposite displacement between the front and rear part of the calcaneus, whereas during eversion tacking affected only the rear part of the bone: these results were confirmed by 3D reconstructions. Henke's axis was described as that for the talonavicular joint, but acceptable for the subtalar joint. Several authors investigating the coordinates of this axis have reported large differences and described screw-like movements, the latter being incompatible with a fixed axis: instantaneous axes, however are compatible with a screw-like movement. The subtalar joint appears to work as a pivot joint during inversion and as a plane joint during eversion. Although Henke's axis has pedagogical value the subtalar joint has a series of instantaneous axes. PMID:11236321

Zographos, S; Chaminade, B; Hobatho, M C; Utheza, G

2000-01-01

240

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

2013-01-01

241

An experimental investigation of underwater pulsed laser forming  

Science.gov (United States)

Laser forming is a new forming technology, which deforms a metal sheet using laser-induced thermal stresses. This paper presents an experimental investigation of pulsed laser forming of stainless steel in water and air. The effects of cooling conditions on bending angle and morphology of the heat affected zone (HAZ) are studied. It is shown that the case of the top surface in air and the bottom surface immersed in water has the greatest bending angle based on the forming mechanism of TGM. The water layer above the sample decreases the coupling energy, leading to a small bending angle. For a thin water thickness (1 mm), the water effects on the HAZ are limited. As water layer thickness increases (5 mm), the concave shape of the HAZ is more remarkable and irregular because the shock waves by high laser energy heating water are fully developed. However, the area and the depth of the HAZ become less significant when water thickness is 10 mm due to the long pathway that laser undergoes.

Shen, Hong; Ran, Maoli; Hu, Jun; Yao, Zhenqiang

2014-11-01

242

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)

243

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

244

Experimental Investigation of Energy Saving in Referigeration System  

Directory of Open Access Journals (Sweden)

Full Text Available This Research deals with experimental investigation of energy saving in refrigeration system. We have all experienced a sensation of heat when passing behind a functioning refrigerator or air conditioner. The cause of this phenomenon is due to thr air condenser, a heat exchanger made up of tubes with air fins attached to the back of the device. This is where the cooling fluid condenses by releasing its heat into the ambient air. To utilize this heat, a water fine water droplet is project to absorb this ambient hot air to the atmosphere. so by decreasing condenser temperature we obtain the system’s energy consumption, humidification processes were initiated. The principle consists of saturating the ambient air in contact with the exchanger by projecting fine water droplets. Humidification of the air intensifies the heat exchange on the air side and reduces the cooling fluid’s condensation temperature. This lowers the compression rate in the cooling cycle and improves the compressor’s consumption of electrical power. The study is mainly focused on the Condenser to reduce the condenser work to save the electrical power.

Inder Singh Nagar

2014-08-01

245

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

246

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

247

Experimental Investigation On Design Of High Pressure Steam Turbine Blade  

Directory of Open Access Journals (Sweden)

Full Text Available 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 the environmental and economical impact of any coal-fired power station. To increasing the efficiency of a typical 500MW turbine by 1% reduces emissions of CO2 from the turbine station, with corresponding reductions in NOx and SOx. In this connection an attempt is made on steam turbine blade performance is important criterion for retrofit coal fired power plant. Based on the research presented modifications to high pressure high pressure steam turbine blades can be made to increase turbine efficiency of the turbine. The results and conclusions are presented for a study concerning the durability problems experienced with steam turbine blades.

SUBRAMANYAM PAVULURI, DR. A. SIVA KUMAR

2013-05-01

248

Experimental Investigations of Flow Past Spinning Circular Cylinders  

Science.gov (United States)

Experimental investigations of flow past spinning circular cylinders were performed. Understanding and control of such flows are crucial to the design of efficient projectile based munitions. Experiments were conducted in an induction-type low-speed wind tunnel that includes a flow-conditioning section, a contraction with a 10:1 area ratio, a plexiglass test section having a nominal rectangular cross-section of 610 x 305 mm, a diffuser section, and two 7.5 hp fans which can provide a maximum velocity of 45 m/s in the test section. The right circular cylinder is spindle-mounted in the test section with a belt-driven motor. Primary instrumentation for this experiment includes pressure probes for mean-velocity measurements, hot-wire anemometer system for measuring turbulence statistics and a flow visualization system. Measured turbulence statistics include all components of the Reynolds stress tensor. Additionally, surface pressure distribution of the cylinder are mapped using static pressure taps and the pressure contribution to the drag force is computed. Mean velocity profiles and the Reynolds stress componets on the cylinder and the wake region are presented and compared with the available data in the literature. Issues related to the development of efficient and appropirate turbulence models are also addressed.

Carlucci, Donald; Thangam, Siva

1999-11-01

249

Border Collision Route to Quasiperiodicity: Numerical Investigation and Experimental Confirmation  

DEFF Research Database (Denmark)

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

Zhusubaliyev, Zhanybai; Mosekilde, Erik

2006-01-01

250

Laboratory and Theoretical Investigations on Mechanical Behavior of PLFG Mixture  

OpenAIRE

Phosphogypsum-lime-flyash-gravel Mixture (PLFG) is usually used to strengthen road foundation of geotechnical engineering. It is important to correctly understand its mechanical behavior before corresponding design. In this present paper, compaction test, one-dimensional compression test and dry-shrinkage test were conducted to determine optimum mixture ration of PLFG. compression test on PLFG with optimum ration was carried out in order to investigate its ...

Wang Wei; Lu Tinghao; Jin Weimin; Chi Xuchao

2013-01-01

251

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

252

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

253

Experimental investigation of two-dimensional MHD turbulence  

International Nuclear Information System (INIS)

Magnetohydrodynamics (MHD) offers a unique opportunity to study the behavior of two-dimensional turbulent flows. It is generally known that a strong external magnetic field B perpendicular to the direction of the mean flow will suppress any velocity fluctuations in the direction of B. In this case, the equations of fluid motion can be integrated analytically along B in the limit of a high Hartmann number M, leading to the so-called ''quasi two-dimensional'' (Q2D) approximation. An experimental configuration was developed which meets these requirements. It consists of a closed loop channel with electrically insulating walls and a rectangular electric potential probe array located in the top Hartmann wall. This probe contains 6 x 11 measurement pins which can be sampled simultaneously at high frequencies, allowing visualisation and statistical analysis of time-dependent flow structures over the area of the probe array. The present work investigates the flow around a circular cylinder whose symmetry axis is aligned with B. It will be seen that the Q2D method can suppress any three-dimensional instabilities that appear in ordinary hydrodynamics. The following results are presented: Determination of the critical Reynolds number Rc for the onset of time-dependent vortex patterns in the cylinder wake depending on M. For comparison with existing theoretical calculations, this experiment is additionally done for a shear flow in a rectangular channel with an inhomoge in a rectangular channel with an inhomogeneous electrical wall conductivity. Both cases show a general Rc(M)-dependence which is recognized as a typical sign of Q2D stability limits., Visualisation of time-dependent vortex structures using still images and time series at different positions in the cylinder wake. For R > 5000, the periodic vortex street is observed to break up as single vortices and vortex groups are leaving the regular pattern in the spanwise direction., The energy equation is deduced for quasi two-dimensional flows and analyzed experimentally to point out the energy transport mechanisms. The results for the production, convection and dissipation of turbulent kinetic energy explain the development and the decay of the vortex street as well as the observed break-up at R > 5000. Special emphasis is placed on the analysis of different dissipation mechanisms in quasi two-dimensional flows. (orig.)

254

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

Directory of Open Access Journals (Sweden)

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

M. van der Perk

2010-02-01

255

The Experimental Manpower Laboratory for Corrections: Phase II. Final Report (March 1, 1970-August 31, 1971).  

Science.gov (United States)

This report covers these five major projects of the Experimental Manpower Laboratory for Corrections: (1) a manpower training program for Alabama prisoners, (2) an experiment in contingency management, (3) implementation of token economy in Draper Correctional Center, (4) a manpower training project for correctional officers, and (5) a followup…

Rehabilitation Research Foundation, Elmore, AL.

256

Experimental Manpower Laboratory for Corrections: Final Interim Report for Phase IV (March 1973 - February 1974).  

Science.gov (United States)

Reports are presented on three phase four projects being carried out by the Experimental Manpower Laboratory for Corrections (EMLC) using a behavioral approach to the problems of the offender. The Mount Meigs Project is concerned with a behavioral management program, using a token economy, in the academic education division of the Alabama…

Rehabilitation Research Foundation, Montgomery, AL.

257

Biodiesel from soybean oil: experimental procedure of transesterification for organic chemistry laboratories  

International Nuclear Information System (INIS)

The transesterification procedure of triacylglycerides from soybean oil (in natura and waste oil) to give biodiesel was adapted to semi-micro laboratory scale as an additional experimental technique of nucleophilic acyl substitution for undergraduate courses in Chemistry and related areas. (author)

258

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

259

Laboratory investigation of the atmospheric oxidation of dimethyl sulfide  

Science.gov (United States)

On a global scale dimethyl sulfide (DMS, CH3SCH3) is the largest natural source of reduced gas phase sulfur and this compound may play an important role in cloud and aerosol formation processes through its atmospheric oxidation products. Clouds and aerosol constitute a major component of the global climate system via the earth's radiation budget. The work comprising this dissertation entails kinetic, spectroscopic, and mechanistic studies of sulfur containing compounds that are key intermediates in the atmospheric oxidation of DMS. The goal of this dissertation is to improve the quantitative understanding of the DMS atmospheric oxidation mechanism through the determination of rate coefficients and product yields of important elementary gas phase reactions. The experimental approach employed utilized laser flash photolysis (LFP) to initiate free radical chemistry coupled with tune-resolved tunable diode laser spectroscopy (TDLAS) and/or time-resolved UV-VIS long path absorption spectroscopy (LPAS) to monitor the time dependent concentrations of reactants or products. Key reactions examined in this dissertation research include: OH + CH3S(O)CH3, CH3SCH2OO + CH 3SCH2OO, Cl- S(CH3)2+ O2/NO/NO 2. Chemical species monitored in the course of these studies include SO2, CH4, HCL CH2O, and CH3 by TDLAS and CH3OO and Cl-S(CH3)2 using UV-VIS absorption spectroscopy.

Urbanski, Shawn Peter

1999-11-01

260

Air/water oxydesulfurization of coal: laboratory investigation  

Energy Technology Data Exchange (ETDEWEB)

Air/water oxidative desulfurization has been demonstrated in autoclave experiments at the Pittsburgh Energy Technology Center for various coals representative of the major US coal basins. This experimentation has shown that the reaction proceeds effectively for pulverized coals at temperatures of 150 to 200/sup 0/C with air at a total system pressure of 500 to 1500 psig. Above 200/sup 0/C, the loss of coal and product heating value increases due to oxidative consumption of carbon and hydrogen. The pyritic sulfur solubilization reactions are typically complete (95 percent removal) within 15 to 40 minutes at temperature; however, significant apparent organic sulfur removal requires residence times of up to 60 minutes at the higher temperatures. The principal products of the reaction are sulfuric acid, which can be neutralized with limestone, and iron oxide. Under certain conditions, especially for high pyritic sulfur coals, the precipitation of sulfur-containing compounds from the products of the pyrite reaction may cause anomalous variations in the sulfur form data. The influence of various parameters on the efficiency of sulfur removal from coal by air/water oxydesulfurization has been studied.

Warzinski, R. P.; Friedman, S.; Ruether, J. A.; LaCount, R. B.

1980-08-01

261

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

262

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

263

An experimental investigation of flow past a dual step cylinder  

Energy Technology Data Exchange (ETDEWEB)

Flow development in the wake of a dual step cylinder has been investigated experimentally using Laser Doppler Velocimetry and flow visualization. The dual step cylinder model is comprised of a large diameter cylinder (D) mounted at the mid-span of a small diameter cylinder (d). The experiments have been performed for a Reynolds number (Re{sub D}) of 1,050, a diameter ratio (D/d) of 2, and a range of large cylinder aspect ratios (L/D). The results show that the flow development is highly dependent on L/D. The following four distinct flow regimes can be identified based on vortex dynamics in the wake of the large cylinder: (1) for L/D {>=} 15, three vortex shedding cells form in the wake of the large cylinder, one central cell bounded by two cells of lower frequency, (2) for 8< L/D {<=} 14, a single vortex shedding cell forms in the wake of the large cylinder, (3) for 2 < L/D {<=} 6, vortex shedding from the large cylinder is highly three-dimensional. When spanwise vortices are shed, they deform substantially and attain a hairpin shape in the near wake, (4) for 0.2 {<=} L/D {<=} 1, the large cylinder induces vortex dislocations between small cylinder vortices. The results show that for Regimes I to III, on the average, the frequency of vortex shedding in the large cylinder wake decreases with L/D, which is accompanied by a decrease in coherence of the shed vortices. In Regime IV, small cylinder vortices connect across the large cylinder wake, but these connections are interrupted by vortex dislocations. With decreasing L/D, the frequency of dislocations decreases and the dominant frequency in the large cylinder wake increases toward the small cylinder shedding frequency. (orig.)

Morton, Chris; Yarusevych, Serhiy [University of Waterloo, Mechanical and Mechatronics Engineering, Waterloo, ON (Canada)

2012-01-15

264

LABORATORY AND NUMERICAL INVESTIGATIONS OF RESIDENCE TIME DISTRIBUTION OF FLUIDS IN LAMINAR FLOW STIRRED ANNULAR PHOTOREACTOR  

Science.gov (United States)

Laboratory and Numerical Investigations of Residence Time Distribution of Fluids in Laminar Flow Stirred Annular Photoreactor E. Sahle-Demessie1, Siefu Bekele2, U. R. Pillai1 1U.S. EPA, National Risk Management Research Laboratory Sustainable Technology Division,...

265

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

266

Experimental investigations of biomass gasification with carbon-dioxide  

Science.gov (United States)

A sustainable energy cycle may include enhanced utilization of solar energy and atmospheric CO2 to produce biomass and enhanced utilization of exhaust CO2 from power plants for synthetic gas production. The reaction of carbon with CO2 is potentially one of the important processes in a future sustainable carbon cycle. Reactions involving carbon and CO2 are also relevant to the chemical process and metal industries. Biomass char has been recognized as a present and future alternative to fossil-fuels for energy production and fuel synthesis. Therefore, biomass char gasification with CO2 recycling is proposed as a sustainable and carbon-neutral energy technology. Biomass char is a complex porous solid and its gasification involves heat and mass transfer processes within pores of multiple sizes from nanometer to millimeter scales. These processes are coupled with heterogeneous chemistry at the internal and external surfaces. Rates for the heterogeneous carbon gasification reactions are affected by inorganic content of the char. Furthermore, pore structure of the char develops with conversion and influences apparent gasification rates. Effective modeling of the gasification reactions has relied on the best available understanding of diffusion processes and kinetic rate property constants from state of the art experiments. Improvement of the influences of inorganic composition, and process parameters, such as pressure and temperature on the gasification reaction rates has been a continuous process. Economic viability of gasification relies on use of optimum catalysts. These aspects of the current status of gasification technologies have motivated the work reported in this dissertation. The reactions between biomass chars and CO2 are investigated to determine the effects of temperature and pressure on the reaction rates for large char particles of relevance to practical gasification technologies. An experimental apparatus consisting of a high-pressure fixed-bed reactor with product gas sampling for tracking the reaction progress, supported by independent gravimetric measurements of mass loss, is described. The effects of pressure and temperature on the char-CO2 reaction are investigated at elevated pressures up to 10 atm. Measurements of reaction rates at multiple temperatures and pressures for a low-ash pinewood char are presented. Kinetic rate parameters for the char-CO2 reaction are reported with detailed uncertainty calculations and discussed in the context of the structural changes of the char with mass loss. The effects of pressure and temperature on the internal mass transfer processes and the intrinsic reaction rates are assessed using Thiele analysis for non-isothermal particles with the nth order and the Langmuir-Hinshelwood kinetic rate models. The effects of potassium, calcium and iron catalysts on the CO2 gasification rates of an activated coconut char are investigated. A catalyst treatment method for obtaining high catalyst loadings (~12 wt. %) is described. The effects of the catalysts on the surface reaction rates and the activation energies are reported. The results of this study are encouraging in the context of potential future discovery of a viable low-temperature catalytic gasification process for sustainable use of biomass as a renewable energy resource. Utilization of plant based substances such as citric acid to provide higher catalytic activity and the potential for utilizing the high initial activity of iron by using rust proofing compounds for maintaining high reactivity are recommended for further development.

Sircar, Indraneel

267

LABORATORY INVESTIGATIONS OF SILICATE MUD CONTAMINATION WITH CALCIUM  

Directory of Open Access Journals (Sweden)

Full Text Available The silicate-based drilling fluid is a low solids KCl/polymer system with the addition of soluble sodium or potassium silicate to enhance inhibition and wellbore stability. Silicate-based drilling fluids exhibit remarkable shale and chalk stabilizing properties, resulting in gauge hole and the formation of firm cuttings when drilling reactive shales and soft chalks. Silicates protect shales by in-situ gellation when exposed to the neutral pore fluid and precipitation, which occurs on contact with divalent ions present at the surface of the shale. Also, silicates prevent the dispersion and washouts when drilling soft chalk by reacting with the Ca2+ ions present on chalk surfaces of cutting and wellbore to form a protective film. The silicate-based drilling fluid can be used during drilling hole section through shale interbeded anhydrite formations because of its superior shale stabilizing characteristics. However, drilling through the anhydrite can decrease the silicate concentration and change rheological and filtration fluid properties. So, the critical concentration of calcium ions should be investigated by lab tests. This paper details the mechanism of shale inhibition using silicate-based drilling fluid, and presents results of lab tests conducted to ascertain the effect of Ca2+ ions on silicate level in the fluid and the fluid properties.

Nediljka Gaurina-Me?imurec

2004-12-01

268

Laboratory and Theoretical Investigations on Mechanical Behavior of PLFG Mixture  

Directory of Open Access Journals (Sweden)

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

Wang Wei

2013-01-01

269

Site Safety Plan for Lawrence Livermore National Laboratory CERCLA investigations  

Energy Technology Data Exchange (ETDEWEB)

The safety policy of LLNL is to take every reasonable precaution in the performance of work to protect the environment and the health and safety of employees and the public, and to prevent property damage. With respect to hazardous agents, this protection is provided by limiting human exposures, releases to the environment, and contamination of property to levels that are as low as reasonably achievable (ALARA). It is the intent of this Plan to supply the broad outline for completing environmental investigations within ALARA guidelines. It may not be possible to determine actual working conditions in advance of the work; therefore, planning must allow the opportunity to provide a range of protection based upon actual working conditions. Requirements will be the least restrictive possible for a given set of circumstances, such that work can be completed in an efficient and timely fashion. Due to the relatively large size of the LLNL Site and the different types of activities underway, site-specific Operational Safety Procedures (OSPs) will be prepared to supplement activities not covered by this Plan. These site-specific OSPs provide the detailed information for each specific activity and act as an addendum to this Plan, which provides the general plan for LLNL Main Site operation.

Bainer, R.; Duarte, J.

1993-07-01

270

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

International Nuclear Information System (INIS)

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

271

Experimental investigation of Ca isotopic fractionation during abiotic gypsum precipitation  

Science.gov (United States)

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

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

2014-03-01

272

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

273

Experimental and Numerical Investigation of Flows in Expanding Channels  

Energy Technology Data Exchange (ETDEWEB)

We present an experimental realization of the classical Jeffery-Hamel flows inside a wedge-shaped channel. We compare the measured velocity fields with the predictions of Jeffery-Hamel theory. A detailed experimental study of bifurcation diagrams for the solutions reveals the absolute stability of the pure outflow solution and an interesting hysteretic structure for bifurcations. We also observe a multiple vortex flow regime predicted earlier numerically and analytically. Experimental studies of the stability of the flow to perturbations at the channel exit are also conducted.

Vorobieff, Peter; Putkaradze, Vakhtang

2008-10-24

274

Valorization of rehydrated Deglet-Nour dates by an experimental investigation of solar drying processing method  

International Nuclear Information System (INIS)

Highlights: • A laboratory scale direct solar dryer was constructed and investigated. • The solar drying of hard date palm fruits, Deglet-Nour variety, was studied. • Three improvements in the dryer operating modes were proposed and compared. • Combination drying mode has been selected as the most adequate process. • Selected mode ensures a high quality of product and allows short duration of treatment. - Abstract: In objective to valorize hard Deglet-Nour dates, a new postharvest processing method was proposed and investigated using a laboratory scale direct solar dryer. Date samples were soaked in distilled water then dried by solar drying mean. In order to improve the quality and consumer acceptance of this date variety, three proposed drying enhancements: drying under shade (DUS), drying with photovoltaic powered ventilation (DSV) and combination drying mode (DCM) were tested and compared with the basis case of natural ventilation drying (DNV). The obtained experimental results classified the drying with solar ventilation drying mode (DSV) and combination drying mode (DCM) in favorable operating conditions needed for the studied case. Measured air drying temperatures ranged between 41.8 and 56.0 °C and 39.3 and 51.2 °C respectively for the two above techniques. The drying duration to obtain the standard moisture content (0.35 kg/kg DM) was respectively 5.25 and 8 h. Regarding quality criteria and processing time, the combination drying mode was selected as the most adequate process

275

Experimental investigation of low-lying states of pionic atoms  

International Nuclear Information System (INIS)

We propose to study pionic atoms in low-lying states. The pions will be produced with the help of recoil free kinematics at small energies in the laboratory. A dedicated detector will be applied allowing the measurements of the width as well as the energy shift of these states

276

Experimental investigation of low-lying states of pionic atoms  

Energy Technology Data Exchange (ETDEWEB)

We propose to study pionic atoms in low-lying states. The pions will be produced with the help of recoil free kinematics at small energies in the laboratory. A dedicated detector will be applied allowing the measurements of the width as well as the energy shift of these states.

Amian, W.B.; Cloth, P.; Djaloeis, A.; Filges, D.; Gotta, D.; Kilian, K.; Machner, H.; Morsch, H.P.; Protic, D.; Riepe, G.; Roderburg, E.; von Rossen, P.; Turek, P.; Watzlawik, K.H. (Institut fuer Kernphysik, Forschungszentrum Juelich, Germany (DE)); Jarczyk, L.; Smyrski, J.; Stralkowski, A. (Institut of Physics, Jagellonian University, Krakow, Poland (PL)); Budzanowski, A.; Dabrowski, H.; Skwirczynska, I. (Institut of Nuclear Physics, Krakow, Poland (PL)); Plendl, H. (Florida State University, Tallahassee, Florida, (USA)); Konijn, J. (NIKEF K, Amsterdam, Netherlands (NL))

1991-04-10

277

EXPERIMENTAL INVESTIGATION OF DEFROST USING WARM LIQUID REFRIGERANT  

Science.gov (United States)

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

278

Experimental investigation of transverse velocity estimation using cross-correlation  

DEFF Research Database (Denmark)

A technique for estimating the full flow velocity vector has previously been presented by our group. Unlike conventional estimators, that only detect the axial component of the flow, this new method is capable of estimating the transverse velocity component. The method uses focusing along the flow direction to produce signals that are influenced by the shift of the scatterer's position. The signals are then cross-correllated to find the shift in position and thereby the velocity. The performance of the method is investigated using both a flow phantom and in-vivo measurements. A flow phantom capable of producing a parabolic flow profile was measured with a B-K Medical 8804 7.5 MHz linear array transducer. A plastic tube with an entrance length of 130 cm and a diameter of 17 mm. was used with an EcoWatt 1 pump generating a volume flow of 93.4 l/h corresponding to a peak velocity in the tube of 0.23 m/s. The volume flow was determined by a Danfoss MAG 1100 flow meter. The velocity profiles were measured for different beam-to-flow angles of 90, 65, and 45 degrees. A Harming apodized beam focused at the vessel was transmitted using 64 elements and the received signals on all elements were sampled at 40 MHz and 12 bits in parallel using our experimental ultrasound scanner. Three hundred and seventy pulse echo measurements were acquired for each angle at a pulse repetition frequency of 5 kHz. The field in a number of points on lines parallel to the flow was calculated by focusing the 64 channels;of data. A mean parabolic velocity profile was obtained for purely transverse flow with a mean bias to the true profile of -2.5% relative to the peak velocity and a standard deviation of 13.3% relative to the peak velocity. Twenty pulse-echo lines were used for each estimate and 18 profiles were obtained. For a beam-to-flow angles of 45 and 65 degrees the corresponding numbers were a mean relative bias of less than 4.0% and a relative standard deviation of 3.0% or less, when using 10 pulse-echo lines and 36 profiles. In-vivo measurements have also been performed on the carotid artery on a male volunteer and the flow at an angle of 701 was successfully estimated.

Bjerngaard, Rasmus; Jensen, JØrgen Arendt

2001-01-01

279

Experimental Investigation of Ice Accretion Effects on a Swept Wing  

Science.gov (United States)

An experimental investigation was conducted to study the effects of 2-, 5-, 10-, and 22.5-min ice accretions on the aerodynamic performance of a swept finite wing. The ice shapes tested included castings of ice accretions obtained from icing tests at the NASA Glenn Icing Research Tunnel (IRT) and simulated ice shapes obtained with the LEWICE 2.0 ice accretion code. The conditions used for the icing tests were selected to provide five glaze ice shapes with complete and incomplete scallop features and a small rime ice shape. The LEWICE ice shapes were defined for the same conditions as those used in the icing tests. All aerodynamic performance tests were conducted in the 7- x 10-ft Low-Speed Wind Tunnel Facility at Wichita State University. Six component force and moment measurements, aileron hinge moments, and surface pressures were obtained for a Reynolds number of 1.8 million based on mean aerodynamic chord and aileron deflections in the range of -15o to 20o. Tests were performed with the clean wing, six IRT ice shape castings, seven smooth LEWICE ice shapes, and seven rough LEWICE ice shapes. Roughness for the LEWICE ice shapes was simulated with 36-size grit. The experiments conducted showed that the glaze ice castings reduced the maximum lift coefficient of the clean wing by 11.5% to 93.6%, while the 5-min rime ice casting increased maximum lift by 3.4%. Minimum iced wing drag was 133% to 3533% greater with respect to the clean case. The drag of the iced wing near the clean wing stall angle of attack was 17% to 104% higher than that of the clean case. In general, the aileron remained effective in changing the lift of the clean and iced wings for all angles of attack and aileron deflections tested. Aileron hinge moments for the iced wing cases remained within the maximum and minimum limits defined by the clean wing hinge moments. Tests conducted with the LEWICE ice shapes showed that in general the trends in aerodynamic performance degradation of the wing with the simulated ice shapes were similar to those obtained with the IRT ice shape castings. However, in most cases, the ice castings resulted in greater aerodynamic performance losses than those obtained with the LEWICE ice shapes. For the majority of the LEWICE ice shapes, the addition of 36-size grit roughness to the smooth ice shapes increased aerodynamic performance losses.

Papadakis, M.; Yeong, H. W.; Wong, S. C.; Vargas, M.; Potapczuk, M.

2005-01-01

280

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

281

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

282

Experimental investigation on water film behavior falling on vertical plate  

International Nuclear Information System (INIS)

In this paper, experimental studies on falling water film behaviour on vertical flat plat are carried out in WABREC apparatus. The Reynolds number ranges from 50 to 900. Capacitance probes and high speed camera are adopted to measure the water film thickness and wave velocity. The data are compared with the theoretical solutions and other experiments available in the open literature, and good agreement is obtained. Experimental results on film thickness, its probability density function and wave velocity are presented and discussed. (authors)

283

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

284

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

International Nuclear Information System (INIS)

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

285

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

CERN Document Server

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

Shore, Jesse; Lazer, David

2014-01-01

286

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

International Nuclear Information System (INIS)

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

287

Assessment and investigation of science laboratory skills among year 5 students  

Science.gov (United States)

In line with the current interest in alternative and authentic assessment, this study focused on the evaluation of students' performance on science laboratory process skills. A sample of 147 year 5 students from six schools responded to laboratory process skills tests which assess investigating, performing and reasoning in the content areas of biology, chemistry and physics. The data were analysed to provide information about students' overall practical performance and to identify specific preinstructional conceptions and erros. An investigation of predictors of laboratory performance revealed significant associations between performance and amount of homework done and students' perceptions of several aspects of the classroom environment (personalisation, investigation and organisation). The gender differences commonly found in science achievement were absent when laboratory performance was used as the criterion.

Deture, Linda R.; Fraser, Barry J.; Doran, Rodney L.

1995-09-01

288

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

289

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

International Nuclear Information System (INIS)

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

290

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

Energy Technology Data Exchange (ETDEWEB)

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

Fiereder, R; Riemann, S; Schilling, R, E-mail: fiereder@lhm.mw.tum.d [Department of Fluid Mechanics, Technische Universitaet Muenchen Bolzmannstrasse 15, Garching, 85748 (Germany)

2010-08-15

291

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

Science.gov (United States)

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

Fiereder, R.; Riemann, S.; Schilling, R.

2010-08-01

292

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

International Nuclear Information System (INIS)

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

293

Theoretical and experimental investigation of cosmogenic radioisotope production in germanium  

Science.gov (United States)

Rates were calculated for the cosmic-ray-induced production of 3H, 54Mn, 57Ni, 57,58Co, 65,67Ga, 65Zn, and 68Ge in natural germanium using two experimental neutron spectra from the literature. Reaction excitation functions were computed with a nuclear spallation code. Experimental production rates of 54Mn, 57,58Co, 65Zn, 67Ga and 68Ge were derived from background spectra of natural isotopic abundance germanium detectors. The rate for 57Co was also derived from data taken with a detector fabricated from germanium isotopically enriched to 86% 76Ge and ˜14% 74Ge. The calculated and experimental data are in agreement within a factor of two and in many cases within 30%.

Avignone, F. T.; Brodzinski, R. L.; Collar, J. I.; Miley, H. S.; Garcia, E.; Morales, A.; Morales, J.; Nuñez-Lagos, R.; Reeves, J. H.; Saenz, C.; Villar, J. A.

1992-07-01

294

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

295

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

296

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

297

Current experimental investigations on modern masonry at University of Minho  

OpenAIRE

The paper presents and describes the main issues related to two systems on modern masonry currently under development at University of Minho, one based on lightweight concrete blocks and another based on reinforced concrete block masonry. The details of the experimental work being carried out are addressed and preliminary test results obtained for lightweight concrete block masonry are provide

Lourenc?o, Paulo B.; Vasconcelos, Grac?a; Gouveia, Joa?o P.; Haach, V.

2006-01-01

298

Experimental Verification of the Petroelastic Model in the Laboratory - Fluid Substitution and Pressure Effects.  

OpenAIRE

The poroelastic model is a major component in the workflows for the interpretation of time-lapse (or 4D) seismic data in terms of fluid repartition and/or pressure variation during the exploitation of reservoirs. This model must take into account both the fluid substitution effect and the pressure variation effect on the measured seismic parameters (velocities, impedance). This paper describes an experimental verification in the laboratory of this model. Regarding fluid substitution, Biot- Ga...

Rasolofosaon, Patrick; Zinszner, Bernard

2012-01-01

299

Experimental Investigation of Two-Phase Flow in Rock Salt  

Energy Technology Data Exchange (ETDEWEB)

This Test Plan describes procedures for conducting laboratory scale flow tests on intact, damaged, crushed, and consolidated crushed salt to measure the capillary pressure and relative permeability functions. The primary focus of the tests will be on samples of bedded geologic salt from the WIPP underground. However, the tests described herein are directly applicable to domal salt. Samples being tested will be confined by a range of triaxial stress states ranging from atmospheric pressure up to those approximating lithostatic. Initially these tests will be conducted at room temperature, but testing procedures and equipment will be evaluated to determine adaptability to conducting similar tests under elevated temperatures.

Malama, Bwalya; Howard, Clifford L.

2014-07-01

300

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)

301

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

International Nuclear Information System (INIS)

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

302

An experimental investigation into the behavior of glassfiber reinforced polymer elements at elevated temperatures  

Science.gov (United States)

This thesis presents a literature review and results of an experimental study about the effects of high temperatures and cyclic loading on the physical and mechanical properties of pultruded glass fiber reinforced polymer (GFRP) square tubes used in civil engineering structural applications. Most laboratory researches have focused mainly on the effect of elevated temperature on the compressive strength of the GFRP square tubes. Limited research has focused on the tensile strength of GFRP coupons under elevated temperatures. Dynamic Mechanical Analyses (DMA) was performed to assess the viscoelastic behavior including the glass transition temperature of GFRP. Sixteen GFRP coupons were tested under elevated temperatures to investigate the tensile strength and the effect of elevated temperatures to the tensile strength of GFRP. The results of an experimental program performed on fifty GFRP square tubes with different designs in 1.83m at normal temperatures were discussed to investigate compression performance. Another experimental program was performed on 20 GFRP square tubes with different designs in 1.22m under elevated temperatures. The experiments results were discussed and showed that the compressive strength of GFRP material was influenced by several factors including the glass transition v temperature and the connection bolts. Failure modes under 25°C and 75°C were crushing and the failure modes with the temperatures above 75°C were not typical crushing due to the glass transition of GFRP. Sixteen GFRP square tubes with length of 0.61m were tested with the same experimental program under elevated temperatures as the control group. Twelve GFRP square tubes with the same size were subjected to cyclic loading under elevated temperatures to investigate the effect of the cyclic loading to the compression properties of GFRP material. According to the experimental results and the discussion, the stiffness was reduced by the cyclic loading. On the contrary, the influence of the cyclic loading was not obvious compared to the GFRP specimens subjected to normal displacement control loading. The higher temperature made the stiffness of GFRP more sensitive to the cyclic loading.

Qian, Kenny Zongxi

303

Experimental investigation and modeling of scale effects in jet ejectors  

International Nuclear Information System (INIS)

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.

304

Experimental investigation of defect states in amorphous chalcogenide glasses  

International Nuclear Information System (INIS)

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

305

Magnetic resonance investigations of experimental renal vein ligation  

International Nuclear Information System (INIS)

Experimental ligation of the renal veins in rats indicate highly significant and characteristic changes within two hours, consisting of significant prolongation of T2 relaxation time in the cortex and T2 shortening in the medulla. In addition, there is a considerable increase in the size of the kidney, due to swelling of the cortex. T2 prolongation of the cortex is most marked between 30 hours and two to four days after ligation of the vein. In the following weeks there is a return to normal. T2 of the medulla at two to three weeks after ligation shows highly significant reduction compared with the normal side and, at this time, the size of the experimental kidney is significantly less than the opposite kidney. These results indicate that magnetic resonance tomography is a highly sensitive method for the early demonstration of renal vein thrombosis. (orig.)

306

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

307

Cognitive triggers of auditory hallucinations: an experimental investigation.  

OpenAIRE

It has proved difficult to establish the internal process by which mental events are transformed into auditory hallucinations. The earlier stages of the generation of hallucinations may prove more accessible to research. Cognitions have been reported by patients as a trigger of auditory hallucinations, but the role of these preceding thoughts has not been causally determined. Therefore, the role of cognition in triggering auditory hallucinations was tested in an experimental study. Thirty ind...

Stinson, K.; Valmaggia, Lr; Antley, A.; Slater, M.; Freeman, D.

2010-01-01

308

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

309

Experimental and computational investigations of biomass mixing and combustion processes  

OpenAIRE

Biomass is considered to be a promising source of sustainable energy and consequently it is attracting more research attention. The focus of this ongoing study is on the performance of biomass combustion processes. Computational fluid dynamics (CFD) techniques are planned to simulate the combustion process in various models. This is done in parallel with experimental work to understand the mixing and combustion behaviour biomass. For this purpose CFD models based on both Euler-Lag...

Alganash, B. S.; Paul, M. C.; Watson, I. A.

2011-01-01

310

Experimental and numerical investigations of dike-break induced flows  

OpenAIRE

Experimental model data are compared with numerical computations of dike-break induced flows, focusing on the final steady state. An idealised scale model was designed reproducing the specific boundary conditions of dike breaks. Discharges, water levels and depth profiles of horizontal velocities were recorded and validated by numerical modeling. The latter was performed by two different models solving the two-dimensional depth-averaged shallow water equations, namely a total variation dimini...

Roger, Sebastian; Dewals, Benjamin; Erpicum, Se?bastien; Schwanenberg, Dirk; Schu?ttrumpf, Holger; Ko?ngeter, Ju?rgen; Pirotton, Michel

2009-01-01

311

Experimental investigation of the 61?+ ‘shelf' state of KCs  

Science.gov (United States)

We report the first experimental observation of the 61?+ state in the KCs molecule. Polarization labelling spectroscopy technique was applied to determine energies of about 1000 rovibrational levels in this state, most of them strongly perturbed by the neighbouring 43? state levels. The inverted perturbation approach was used to construct the irregular potential energy curve of the 61?+ state. It is compared with the recent theoretical calculations to show that Hund's coupling case (a) is proper for description of this state.

Szczepkowski, J.; Grochola, A.; Jastrzebski, W.; Kowalczyk, P.

2014-10-01

312

Final Report: Experimental Investigation of Nonlinear Plasma Wake-Fields  

Energy Technology Data Exchange (ETDEWEB)

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.

Rosenzweig, J.

1997-10-31

313

Experimental investigation of delayed self-interference for single photons  

OpenAIRE

A photon echo experiment has been performed using accumulated highly attenuated laser pulses. We show experimentally that the photon echo process can be performed with, on the average, less than one photon in each pair of excitation pulses. The results support an interpretation where this non-linear process can be performed with, on the average, less than one photon shared between two of the optical fields involved in the degenerate four-wave mixing process. Further, we argu...

Ohlsson, N.; Nilsson, M.; Kro?ll, Stefan

2003-01-01

314

Experimental Investigation of In Situ Cleanable HEPA Filters  

International Nuclear Information System (INIS)

Savannah River Technology Center (SRTC) located at Westinghouse Savannah River Site (WSRS) is currently conducting research and development experimentation to develop a replacement of the conventional high efficiency particulate air (HEPA) filter system currently used by commercial industry and DOE facilities. It has been determined that a cleanable or regenerable HEPA filter system may be the most cost effective and efficient HEPA filter system to be considered for use in a more safe and reliable work environment

315

Experimental investigation of charged liquid jet efflux from a capillary  

Science.gov (United States)

The shapes and electrical characteristics of charged liquid (water, ethanol, glycerol, castor oil) jets emitted from a metal capillary have been experimentally studied depending on the applied high voltage. A map of efflux regimes in the flow velocity-applied voltage coordinates is constructed for water. The effects of medium viscosity, surface tension, and charge relaxation time on the laws of jet efflux are analyzed.

Zhakin, A. I.; Belov, P. A.; Kuz'ko, A. E.

2013-03-01

316

Experimental and Numerical Investigation of Flows in Expanding Channels  

Energy Technology Data Exchange (ETDEWEB)

This is the first year progress report for our grant starting Feb. 1 2004. It describes experimental and theoretical achievements during the first year, lists the articles published during this period, as well as the progress of the graduate students supported by this grant. The timeline for the future is outlined; the current results convince us that the work will be done on time and within the budget.

Vakhtang Putkaradze Peter Vorobieff

2004-10-28

317

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

318

Theoretical and experimental investigations on incompressible flow through labyrinths  

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-07-01

319

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

320

Experimental and CFD investigation of gas phase freeboard combustion  

DEFF Research Database (Denmark)

Reliable and accurate modeling capabilities for combustion systems are valuable tools for optimization of the combustion process. This work concerns primary precautions for reducing NO emissions, thereby abating the detrimental effects known as “acid rain”, and minimizing cost for flue gas treatment. The aim of this project is to provide validation data for Computational Fluid Dynamic (CFD) models relevant for grate firing combustion conditions. CFD modeling is a mathematical tool capable of predicting fluid flow, mixing and chemical reaction with thermal conversion and transport. Prediction of pollutant formation, which occurs in small concentrations with little impact on the general combustion process is in this work predicted by a post-processing step, making it less computationally expensive. A reactor was constructed to simulate the conditions in the freeboard of a grate fired boiler, but under well-defined conditions. Comprehensive experimental data for velocity field, temperatures, and gas compositionare obtained from a 50 kW axisymmetric non-swirling natural gas fired combustion setup under two different settings. Ammonia is added to the combustion setup in order to simulate fuel-NO formation during grate firing biomass combustion conditions. The experimental results are in this work compared to CFD modeling. The modeling results show, that the CFD model captured the main features of the combustion process and flow patterns. The application of more advanced chemical reaction mechanisms does not improve the prediction of the overall combustion process, but do provide additional formation about species (especially H2 and radicals), which is desirable for post-processing pollutant formation. NO formation is post-processed using various ammonia oxidation schemes and different post-processing techniques. The results in some cases provide a reasonable agreement with the experimental data. In general the application of advanced combustion modeling and more advanced ammonia oxidation mechanisms does not improve the agreement with experimental data compared to the simple eddy dissipation (mixed is burned) approach with post processing of a global combustion mechanism. The experimental setup does however not serve as a perfect validation case. The Reynolds numbers in the system put the flow regime in the transitional region, where turbulence modeling is difficult. Furthermore, the inclined jets show an affinity towards wall attachment, the entire modeling result is very sensitive to the prediction of these jets.

Andersen, Jimmy

2009-01-01

321

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.

2014-03-01

322

Theoretical and experimental investigations of antennas and waves in plasma  

Science.gov (United States)

The near field characteristics of an antenna when it is covered by a plasma sheath were investigated. The areas of investigation were: (1) current distribution, (2) input admittance, and (3) radiation pattern as functions of the electrical length of the antenna. Diagnostic measurements were also made to determine the properties of the plasma. A numerical method was evolved to solve the problem of a finite cylindrical antenna in an infinite plasma column.

1972-01-01

323

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)

324

Experimental Investigation of Use of Microsilica in Self Compacting Concrete  

Directory of Open Access Journals (Sweden)

Full Text Available This paper is described Project in detail and presents laboratory observation. Microsilica is used as a 10% replacement of cement by weight. Various test were conducted on fine aggregate & coarse aggregate, to determine specific gravity, bulk density, fineness modulus of aggregate, concrete mix proportion design using this parameter..For conventional concrete water cement ratio of 0.4 and for microsilica concrete is increased water contain about 20liter/m3. Water demand increases in proportion to the amount of microsilica added. Mixing the concrete and various test are conducted on fresh concrete i.e. Slump flow, V- Funnel, L-Box, U-Box and result are obtained. Using this concrete cube specimen are cast for testing different hardened properties of concrete. i.e. 3 Days, 7 Days, 14 Days, 28 Days Compressive strength of concrete.

Mr.Ashok P. Kalbande

2012-05-01

325

Investigations of the SAD design parameters for optimum experimental performance  

International Nuclear Information System (INIS)

A project of fast experimental accelerator driven system called SAD - Subcritical Assembly in Dubna - containing MOX fuel and driven by 660 MeV proton beam is described and analysed. It is shown by design calculations that the necessity exists for certain modifications, allowing for better reliability of measurements of system time characteristics. Different solutions such as: cadmium separation of the biological concrete shield, admixtures of B2O3 to the concrete and certain slowing down of neutrons were analysed. Experiments on a bare spallation targets were conducted and the production of radionuclides in the lead target were measured and compared with calculations

326

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

327

Numerical and experimental investigation of thermal louvers for space applications  

Scientific Electronic Library Online (English)

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.

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

328

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)

329

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

330

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

331

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

332

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

333

The experimental investigation of the alpha decay of transactinium isotopes  

International Nuclear Information System (INIS)

Current methods and existing experimental facilities to measure the energy spectrum of alpha radiation are described, and a list of recent publication containing compilation on alpha-decay data is given. The review concentrates on the presentation of the current status of alpha decay data of the transactinium isotopes. The values and uncertainties of the absolute energies and the relative intensities of alpha-groups are tabulated. Suggested ''best values'' of decay half-lives of some of the most often used long-lived transactinium isotopes are listed. (author)

334

Power characteristics in GMAW: Experimental and numerical investigation  

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-03-01

335

An experimental investigation of pulse tube refrigeration heat transfer rates  

International Nuclear Information System (INIS)

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

336

Experimental Investigations of the Electron Cloud Key Parameters  

CERN Document Server

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

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

1999-01-01

337

Non-rectangular RC walls: A review of experimental investigations  

OpenAIRE

When compared to tests on reinforced concrete (RC) walls with a rectangular or barbelled cross-section, only very few tests on RC walls with open cross-section exist. Most of these walls were subjected to unidirectional or bidirectional loading along one or both of the principal axes of the wall section. It was rare that tests were done using load paths that did not follow the principal axes. This article presents a review of experimental tests of non-rectangular RC walls with open cross-sect...

Constantin, Raluca; Beyer, Katrin

2014-01-01

338

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

339

Overview of experimental results obtained under the Prestressed Concrete Nuclear Pressure Vessel Development Program at the Oak Ridge National Laboratory  

International Nuclear Information System (INIS)

Under the Prestressed Concrete Nuclear Pressure Vessel Development Program at the Oak Ridge National Laboratory, various aspects of Prestressed Concrete Pressure Vessels (PCPVs) are investigated and evaluated with respect to reliability, structural performance, constructability, and economy. Based upon identified needs, analytical and experimental investigations are conducted. Areas of interest include finite-element analysis development, materials and structural behavior tests, instrumentation evaluation and development, and structural model tests. Studies have been recently completed in the following areas: concrete embedment instrumentation systems for PCPVs, grouted-nongrouted prestressing systems, acoustic emission as a technique for structural integrity monitoring, and model tests of steam-generator cavity closure plugs for a Gas-Cooled Fast Reactor (GCFR). An overview of results is presented

340

An experimental investigation of post dryout heat transfer  

International Nuclear Information System (INIS)

The present report contains the results of post-dryout measurements which have been carried out in the Department of Nuclear Reactor Engineering at the Royal Institute of Technology. More than 15000 heat transfer coefficients were obtained for electrically heated round tubes in the post-dryout regime, covering the following ranges of parameters: Heated length L=7000 mm, Inner diameter d(sub)i=14.90, 10.00 and 24.69 mm, Inlet subcooling ?t(sub)i=10degreeC, Pressure p=30-205 bar, Mass velocity G=500-3000 kg/m2s, Heat flux g/A=9-125 W/cm2, PDO steam quality x(sub)PDO=0.03-1.66. A brief description of the experimental equipment is given as well as a table containing the experimental results. The data have been stored on a tape which is available at the department of Nuclear Reactor Engineering at the Royal Institute of Technology. (author)

341

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

342

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)

343

Investigating climate change and reproduction: experimental tools from evolutionary biology.  

Science.gov (United States)

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. PMID:24832232

Grazer, Vera M; Martin, Oliver Y

2012-01-01

344

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

345

Vibroseismic Investigations of Mud Volcano, Experimental Results and Mathematical Modeling  

Science.gov (United States)

The theoretical and experimental fundamentals of the monitoring system of living volcanoes with the use of powerful vibroseismic sources are presented. A method to calculate Green's function for inhomogeneous models of media with the employment of the reciprocity principle was developed for the numerical modeling of arbitrary structures, in particular, magma chambers. The medium is assumed to be consisting of arbitrary blocks. Some part of the medium can be a layered pack with an arbitrary number of layers. The thickness of the layers and the velocity parameters of the media can be arbitrary quantities in both the layered pack and the block medium. It should be noted that the calculation of Green's function allows simultaneous calculation of the wave fields for an arbitrary number of sources and receivers. This is important also for problems of area seismic prospecting and for solving inverse problems of geophysics by using optimization methods. The results of first experimental works for the Taman mud volcano province are presented. The medium's model in the mud volcano Shugo region obtained on the basis of vibroseismic sounding data was refined by numerical modeling.

Glinsky, B.; Khairetdinov, M.; Fatyanov, A.

2007-12-01

346

Experimental investigations of operation of active-bucket excavators  

Energy Technology Data Exchange (ETDEWEB)

The IGD SO AN SSSR research institute developed and successfully tested experimental units of power shovels with buckets equipped with pneumatic picks. The power shovels are used for mining coal and sedimentary rocks with a medium resistance to digging. The power shovels with pneumatic picks were tested in the Kuzbass. Aleurites and sandstones with a resistance to cutting ranging from 50.0 to 77 MPa as well as black coal with a resistance to cutting from 12.0 to 24.5 MPa were mined by power shovels with buckets equipped with pneumatic picks. Operational experience with experimental units showed that using buckets with pneumatic picks successfully replaced explosive fracturing of strong overburden. Duration of the mining cycle decreased; mining efficiency increased. Dynamic loads on structural elements of power shovel were within permissible limits. Dynamic loads caused by operation of pneumatic picks did not negatively influence service life of the power shovels. Noise and dust pollution were within permissible limits. Grain size distribution of overburden mined by excavators with buckets equipped with pneumatic picks improved. 4 refs.

Mattis, A.R.; Shishaev, S.V. (Institut Gornogo Dela (USSR))

1989-01-01

347

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

348

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

349

Experimental investigation of the reaction at REX-ISOLDE  

CERN Document Server

The particle unbound nucleus $^{10}$Li has been investigated at the newly constructed post-accelerator REX-ISOLDE at CERN via the $^{9}$Li+d to $^{10}$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

350

Experimental investigation of the Fast-SAGD process  

Energy Technology Data Exchange (ETDEWEB)

High pressure and high temperature experiments were conducted to provided insight into the operation of the steam assisted gravity drainage (SAGD) process and its modified Fast-SAGD process. A mechanism for the steam chamber's collapse and recovery was suggested. Steam chamber growth is accelerated sideways in this enhanced recovery method which uses offset wells operated with cyclic steam stimulation (CSS) beside the SAGD well. The enhanced thermal efficiency offered by Fast-SAGD results in better production performance compared to conventional SAGD. The application of the Fast-SAGD process in Alberta's oil sands areas has resulted in higher net present values (NPV) for the low permeability type reservoirs of Cold Lake and Peace River because of lower steam requirements and higher productivity. In this study, the Fast SAGD process was evaluated using an automated process control system for a scaled physical model which represented a bituminous reservoir near Cold Lake being operated at high temperature and high pressure conditions. A suitable permeability of 1.25 Darcy was chosen for the prototype based on numerical simulations. Experimental results revealed that, for the Fast-SAGD process, the overall cumulative oil production is larger and the end-point cumulative steam to oil ratio (CSOR) is higher than for the SAGD process. The authors deduced that for the Fast-SAGD experiment, the steam chamber collapsed because the boiler did not produce a sufficient volume of high quality steam. Numerical simulation results confirmed this assumption. The steam chamber was then restored by modifying the experimental procedure. Best history matches showed the steam quality was 30 per cent during the SAGD and then 15 per cent after starting the CSS. It was concluded that if the same quality of steam were injected into the Fast- SAGD model as in the SAGD case, the experimental results of the Fast-SAGD case would be improved, cumulative production by 70 per cent and the CSOR by 52 per cent. 8 refs., 2 tabs., 24 figs.

Shin, H. [Shell Canada Ltd., Calgary, AB (Canada); Polikar, M. [Alberta Univ., Edmonton, AB (Canada)

2006-07-01

351

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

352

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

353

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

354

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

355

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

356

Experimental Investigation of Supersonic Coplanar Jets within Ejectors  

Science.gov (United States)

This experimental and theoretical work involved reduction of supersonic jet noise using Mach Wave Elimination (MWE), a method that suppresses noise by means of a gaseous layer that envelops the supersonic jet. Also explored was a new method for mixing enhancement in which an axial, secondary flow enhances mixing in a primary flow. The research is relevant to the advent of future supersonic transports that must adhere to the same take-off and landing restrictions as ordinary subsonic aircraft. To reduce noise, one needs to understand the fundamental fluid mechanics of the jet, namely its turbulent structure and mean-flow characteristics, and to perform high-quality noise measurements. The results generated are applicable to free jets as well as to jets within ejectors.

Papamoschou, Dimitri

2001-01-01

357

Experimental Investigation of Dynamic Behavior of Viaducts by Shock Loading  

Directory of Open Access Journals (Sweden)

Full Text Available The viaducts are constructions designed to provide ground communication over different geographical barriers such as examples valleys (depressions. To avoid partial or total destruction that may occur after dynamic stress from road (or railroad or seismic activity, in viaducts structure is placed systems for dynamic isolation. Thus, the viaduct deck is mounted on viscoelastic type systems designed to provide protection from the shock loading. Over time, due to an intensive and varied of dynamic loadings, these isolation systems suffer degradation of viscoelastic links, something that leads to uncontrolled movements of the system. In this work, are established and quantified on experimental way, kinematics parameters of the vibration of the viaduct deck loading by shocks, which will be monitored over time to establish the degree of normality in the functioning of viscoelastic systems.

Adrian Leopa

2011-09-01

358

Experimental Investigation of the Equal Channel Forward Extrusion Process  

Directory of Open Access Journals (Sweden)

Full Text Available Among all recognized severe plastic deformation techniques, a new method, called the equal channel forward extrusion process, has been experimentally studied. It has been shown that this method has similar characteristics to other severe plastic deformation methods, and the potential of this new method was examined on the mechanical properties of commercial pure aluminum. The results indicate that approximate 121%, 56%, and 84% enhancements, at the yield strength, ultimate tensile strength, and Vickers micro-hardness measurement are, respectively, achieved after the fourth pass, in comparison with the annealed condition. The results of drop weight impact test showed that the increment of 26% at the impact force, and also decreases of 32%, 15%, and 4% at the deflection, impulse, and absorbed energy, are respectively attained for the fourth pass when compared to the annealed condition. Furthermore, the electron backscatter diffraction examination revealed that the average grain size of the final pass is about 480 nm.

Mahmoud Ebrahimi

2015-03-01

359

Experimental investigation on an S-band relativistic klystron oscillator  

International Nuclear Information System (INIS)

The modulation mechanism and RF extraction of an S-band relativistic klystron oscillator were studied via experiment. It is found that intense relativistic electron beams(IREBs) can generate intense current modulation when the IREBs drift through three pillboxes with high coupling. After bunching in the downstream the modulated IREBs can excite high power micro- wave in the triaxial cavity. The RKO has properties of short oscillating time, compact geometry and high beam-wave conversion efficiency. Using a 1 MV/13 kA/40 ns electron beam and leading magnetic field of 0.9 T, 3.5 GW radiated power was extracted in 20 ns FWHM pulses at 2.86 GHz. The beam-wave transition efficiency is 29%, and the instantaneous bandwidth is 2%. The radiated power is 3.4 GW with the efficiency of 26% when repetitive pulse frequency of IREBs is 20 Hz. The experimental results agree well with the simulation ones. (authors)

360

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

361

Experimental investigation on the avoidance of self-excited vibrations.  

Science.gov (United States)

Self-excited vibrations are observed in many technical applications. Frictional contacts are often involved in the mechanism which generates vibrations. Reasons for the excitation mechanisms are decreasing friction characteristics depending on the sliding velocity, fluctuating normal loads or different geometrical effects. First, the mechanisms are explained using simple examples. The practical relevance of self-excited, friction-induced vibrations is exemplified with three technical systems: a system with an axial seal; a tread block of a tyre; and a disc brake. The knowledge of the excitation mechanism is necessary to introduce successfully design countermeasures. These measures to avoid self-excited vibrations are important to solve practical problems. They are the main focus of this work. Further, additional passive and active subsystems are described and validated experimentally. Therefore, a large range of design, active and passive solutions are given. PMID:17947204

Kröger, Matthias; Neubauer, Marcus; Popp, Karl

2008-03-13

362

Numerical and experimental investigation of downdraft gasification of woody residues.  

Science.gov (United States)

A pilot scale throated downdraft gasifier was operated with vine prunings as feedstock to assess the effect of biomass loading rate on process performance. A distributed 1D model of mass and heat transfer and reactions was applied to aid the interpretation of experimental evidence. The model takes into account peculiar gasifier design features (air inlets and throat) and it reproduces satisfactorily the temperature profiles and the mass fluxes of gaseous species at different biomass loading rates. The integration of pilot-scale experiments and numerical simulations provides sound indications for the gasifier operation. In particular, simulations performed at different loading rates and feedstock humidity show that steady state operation and stable performance of the gasifier rely on the thermal balance between the enthalpy of cold biomass moving downward and the counter-current radiative heat fluxes moving upward from the oxidation zone. This balance can be destabilized by high loading rate and moisture contents. PMID:23422304

Simone, Marco; Nicolella, Cristiano; Tognotti, Leonardo

2013-04-01

363

EXPERIMENTAL INVESTIGATION & NUMERICAL ANALYSIS OF COMPOSITE LEAF SPRING  

Directory of Open Access Journals (Sweden)

Full Text Available The Automobile Industry has shown keen interest for replacement of steel leaf spring with that of glass fiber composite leaf spring, since the composite material has high strength to weight ratio, good corrosion resistance and tailor-able properties. The objective of present study was to replace material for leaf spring. In present study the material selected was glass fiber reinforced plastic (GFRP and the polyester resin (NETPOL 1011 can be used which was more economical this will reduce total cost of composite leaf spring. A spring with constant width and thickness was fabricated by hand lay-up technique which was very simple and economical. The experiments were conducted on UTM and numerical analysis was done via (FEA using ANSYS software. Stresses and deflection results were verified for analytical and experimental results. Result shows that, the composite spring has stresses much lower than steel leaf spring and weight of composite spring was nearly reduced up to 85%.

K. K. JADHAO,

2011-06-01

364

Experimental investigations of the hydraulics of PFBR steam generator  

International Nuclear Information System (INIS)

The 500 MWe Prototype Fast Breeder Reactor (PFBR) being constructed at Kalpakkam in India, employ liquid sodium as the coolant. Steam generator units are shell and tube heat exchangers with sodium flowing on the shell side and water/steam on the tube side. Liquid sodium enters into the shell side through a side nozzle rises up in the annular space, enters into the window of tube bundle and then flows down along the tubes exchanging heat. The crossflow at tube bundle window has major influence on the flow-induced vibration (FIV) of the tubes and on the temperature profile of the steam exiting from the tubes. A near uniform flow distribution at the inlet of the tube bundle and optimum crossflow velocity are vital for the above mentioned. A scaled down model of the prototype of size 3/5 with velocity similitude was used to conduct hydraulic studies in water to determine the flow distribution and flow distribution devices were employed to achieve flow uniformity. A 60-degree sector of the PFBR SG was tested in water to establish the velocity profile and to monitor the flow induced vibration characteristics. The results of the experiments were compared with the predictions of the analysis arrived using computational tools. From the experimental studies and the theoretical analysis on the sector model an acceptable velocity distribution for the SG tubes against failure due to FIV has been established. This paper discusses the experimental study, the measurements and the anamental study, the measurements and the analysis of the results. (author)

365

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

366

EXPERIMENTAL INVESTIGATIONS OF THE INTERACTION OF SO(2) WITH MGO.  

Energy Technology Data Exchange (ETDEWEB)

High resolution adsorption isotherms, temperature programmed desorption (TPD), x-ray diffraction (XRD) and x-ray absorption near edge spectroscopy (XANES) methods were used to investigate the interaction of SO{sub 2} with high quality MgO powders. The results of these investigations indicate that when SO{sub 2} is deposited on MgO in monolayer quantities at temperatures near 100K both SO{sub 2} and SO{sub 4} species form that are not removed by simply pumping on the pre-dosed samples at room temperature. TPD and XANES studies indicate that heating of pre-dosed MgO samples to temperatures above 350 C is required for full removal of the SO{sub 3}/SO{sub 4} species. XANES measurements made as a function of film thickness indicate for coverages near monolayer completion that the SO{sub 4} species form first.

FREITAG,A.

1999-11-29

367

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

368

Experimental investigations of helium cryotrapping by argon frost  

International Nuclear Information System (INIS)

At the Karlsruhe Nuclear Research Centre (KfK) cryopumping techniques are being investigated by which the gaseous exhausts from the NET/ITER reactor can be pumped out during the burn-and dwell-times. Cryosorption and cryotrapping are techniques which are suitable for this task. It is the target of the investigations to test the techniques under NET/ITER conditions and to determine optimum design data for a prototype. They involve measurement of the pumping speed as a function of the gas composition, gas flow and loading condition of the pump surfaces. The following parameters are subjected to variations: Ar/He ratio, specific helium volume flow rate, cryosurface temperature, process gas composition, impurities in argon trapping gas, three-stage operation and two-stage operation. This paper is a description of the experiments on argon trapping techniques started in 1990. Eleven tests as well as the results derived from them are described

369

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

370

Experimental investigations of helium cryotrapping by argon frost  

Energy Technology Data Exchange (ETDEWEB)

At the Karlsruhe Nuclear Research Centre (KfK) cryopumping techniques are being investigated by which the gaseous exhausts from the NET/ITER reactor can be pumped out during the burn-and dwell-times. Cryosorption and cryotrapping are techniques which are suitable for this task. It is the target of the investigations to test the techniques under NET/ITER conditions and to determine optimum design data for a prototype. They involve measurement of the pumping speed as a function of the gas composition, gas flow and loading condition of the pump surfaces. The following parameters are subjected to variations: Ar/He ratio, specific helium volume flow rate, cryosurface temperature, process gas composition, impurities in argon trapping gas, three-stage operation and two-stage operation. This paper is a description of the experiments on argon trapping techniques started in 1990. Eleven tests as well as the results derived from them are described.

Mack, A.; Perinic, D. (Karlsruhe Nuclear Research Center, P.O. Box 3640, W-7500 Karlsruhe (DE)); Murdoch, D. (NET-Team, W-8046 Garching (DE)); Boissin, J.C. (L' Air Liquide, F-38360 Sassenage (FR))

1992-03-01

371

Experimental investigation of current free double layers in helicon plasmas  

Energy Technology Data Exchange (ETDEWEB)

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??V{sub p})/(k?T{sub e}) 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.

Sahu, B. B. [Department of Applied Sciences and Humanities, Dronacharya College of Engineering, Gurgaon 123506 (India); Tarey, R. D. [Department of Physics, Indian Institute of Technology, New Delhi 110016 (India); Ganguli, A. [Centre for Energy Studies, Indian Institute of Technology, New Delhi 110016 (India)

2014-02-15

372

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

373

An Experimental Investigation of Flow Across Tube Banks  

Science.gov (United States)

Flow across tube banks was investigated by surveys of total dynamic and static pressure by visualization of the flow through the use of titanium tetrachloride smoke, by thermocouple surveys of heated tubes, and by hot-wire surveys of both heated and unheated tubes. It was found that turbulence increased as the depth of the bank increased and that the broad wake behind each tube affected flow over the succeeding tubes.

Brevoort, M.J.; Tifford, A.N.

1942-01-01

374

Experimental investigation of face stability of shallow tunnels in sand  

OpenAIRE

The face stability of shallow tunnels was investigated with small-scale model experiments at single gravity. Aim of the research was to detect the evolution of failure mechanisms in dense and loose soil samples with varying overburden above the tunnel. Moreover, the quality of proposed theoretical/numerical approaches for the determination of a necessary support pressure pf was assessed. The results indicate that pf is independent of overburden and initial density of the soil. The experimenta...

Kirsch, Ansgar

2008-01-01

375

Experimental investigation into the degradation of model superconducting windings  

International Nuclear Information System (INIS)

Results are reported for an investigation into degradation of critical current in model compound-treated windings fabricated from type KETV-2NT superconducting conductors with nonsteady stabilization. It is shown that the way in which the critical current depends on the heat-removal conditions and the rate of entry of current is determined by a mechanism of steady-state heat release occationed by plastic strain of the winding materials under the action of ponderomotive forces

376

Experimental investigation of DC gas breakdown in argon  

International Nuclear Information System (INIS)

In this paper the DC gas breakdown in argon have been investigated at the different interelectrode gaps L and the discharge tube radius R. The modified Paschen law have been obtained Udc = f (pL, L/R), that is the DC breakdown voltage Udc is the function not only product of the gas pressure p and the interelectrode gap L, but also the function of the ratio L/R

377

Flow in a Pelton Turbine Bucket: Numerical and Experimental Investigations  

OpenAIRE

The aim of the paper is to present the results of investigations conducted on the free surface flow in a Pelton turbine model bucket. Unsteady numerical simulations, based on the two-phase homogeneous model, are performed together with wall pressure measurements and flow visualizations. The results obtained allow defining five distinct zones in the bucket from the flow patterns and the pressure signal shapes. The results provided by the numerical simulation are compared for each zone. The flo...

Perrig, A.; Avellan, F.; Kueny, J. -l; Parkinson, E.; Farhat, M.

2006-01-01

378

Experimental Investigation of Turbulent Fluid Flow through a Rectangular Elbow  

OpenAIRE

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 ...

Arindam Mandal; Somnath Bhattecharjee; Rabin Debnath; Debasish Roy,; Snehamoy Majumder

2010-01-01

379

Experimental investigation into the erosion wear of structural materials  

Science.gov (United States)

Results of investigations into erosion wear of Grade 20Kh13 steel with the collision velocity of rotating samples V imp = 250 m/s with the particles of monodispersed erodent d d = 800 ?m are considered. Substantial distinctions in the development of the erosion process of steel of the same brand subjected to the erodent effect with the same characteristics determined by accidental (unknown) circumstances are shown.

Ryzhenkov, V. A.; Seleznev, L. I.; Mednikov, A. F.; Tkhabisimov, A. B.

2014-08-01

380

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

381

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

382

Experimental Investigation of Shrinkage of Nano Hair Reinforced Concrete  

OpenAIRE

Basically most of cement based mixtures are likely shrinking. Use of fibers is not a new idea in this case. Previously, there were some evidences that horse hair, straw and cotton fibers were used in mud and mortars in ancient times. Then, utilizing these fibers in concrete mixture may increase concrete workability and decrease shrinkage cracks. Due to nano cross-section of hair and its proper tensile strength this project investigates its application to reduce the shrinkage of concrete mixtu...

Yadollah Batebi; Alireza Mirzagoltabar; Seyed Mostafa Shabanian; Sara Fateri

2013-01-01

383

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 ( about5m3). The data provided by this facility can be used in the development and assessment of analytical models used to predict hydrogen combustion behavior

384

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

385

Experimental investigation of ion-ion recombination at atmospheric conditions  

Science.gov (United States)

We present the results of laboratory measurements of the ion-ion recombination coefficient at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at CERN, the walls of which are made of conductive material, making it possible to measure small ions. We produced ions in the chamber using a 3.5 GeV c-1 beam of positively-charged pions (?+) from the CERN Proton Synchrotron (PS) and with galactic cosmic rays, when the PS was switched off. The range of the ion production rate varied from 2 to 100 cm-3s-1, covering the typical range of ionization throughout the troposphere. The temperature ranged from -55 to 20 °C, the relative humidity from 0 to 70%, the SO2 concentration from 0 to 40 ppb, and the ozone concentration from 200 to 700 ppb. At 20 °C and 40% RH, the retrieved ion-ion recombination coefficient was (2.3 ± 0.7) × 10-6cm3s-1. We observed no dependency of the ion-ion recombination coefficient on ozone concentration and a weak variation with sulfur dioxide concentration. However, we found a strong dependency of the ion-ion recombination coefficient on temperature. We compared our results with three different models and found an overall agreement for temperatures above 0 °C, but a disagreement at lower temperatures. We observed a strong dependency of the recombination coefficient on relative humidity, which has not been reported previously.

Franchin, A.; Ehrhart, S.; Leppä, J.; Nieminen, T.; Gagné, S.; Schobesberger, S.; Wimmer, D.; Duplissy, J.; Riccobono, F.; Dunne, E.; Rondo, L.; Downard, A.; Bianchi, F.; Kupc, A.; Tsagkogeorgas, G.; Lehtipalo, K.; Manninen, H. E.; Almeida, J.; Amorim, A.; Wagner, P. E.; Hansel, A.; Kirkby, J.; Kürten, A.; Donahue, N. M.; Makhmutov, V.; Mathot, S.; Metzger, A.; Petäjä, T.; Schnitzhofer, R.; Sipilä, M.; Stozhkov, Y.; Tomé, A.; Kerminen, V.-M.; Carslaw, K.; Curtius, J.; Baltensperger, U.; Kulmala, M.

2015-02-01

386

Advances with the Chinese anthelminthic drug tribendimidine in clinical trials and laboratory investigations.  

Science.gov (United States)

The anthelminthic drug tribendimidine has been approved by Chinese authorities for human use in 2004, and a first comprehensive review was published in Acta Tropica in 2005. Here, we summarise further advances made through additional clinical trials and laboratory investigations. Two phase IV trials have been conducted in the People's Republic of China, the first one enrolling 1292 adolescents and adults aged 15-70 years and the second one conducted with 899 children aged 4-14 years who were infected with one or multiple species of soil-transmitted helminths. Oral tribendimidine (single 400mg enteric-coated tablet given to adolescents/adults and 200mg to children) showed high cure rates against Ascaris lumbricoides (90.1-95.0%) and moderate-to-high cure rates against hookworm (82.0-88.4%). Another trial done in school-aged children using a rigorous diagnostic approach found a cure rate against hookworm of 76.5%. A single oral dose of tribendimidine showed only low cure rates against Trichuris trichiura (23.9-36.8%) confirming previous results. Tribendimidine administered to children infected with Enterobius vermicularis (two doses of 200mg each on consecutive days) resulted in a high cure rate (97.1%). Importantly, a series of randomised, exploratory trials revealed that tribendimidine shows interesting activity against the liver flukes Opisthorchis viverrini and Clonorchis sinensis, the tapeworm Taenia spp. and the threadworm Strongyloides stercoralis with respective cure rates of 70.0%, 40.0%, 53.3% and 36.4%. Pharmacokinetic studies in healthy Chinese volunteers indicated that after oral administration of tribendimidine, no parent drug was detected in plasma, but its primary metabolite, p-(1-dimethylamino ethylimino) aniline (aminoamidine, deacylated amidantel) (dADT), was found in plasma. dADT is then further metabolised to acetylated dADT (AdADT). dADT exhibits activity against several species of hookworm and C. sinensis in experimental studies, similar to that of tribendimidine. First studies elucidating the mechanism of action suggested that tribendimidine is an L-type nicotinic acetylcholine receptor agonist. Additional experimental studies revealed that the anti-parasite spectrum of tribendimidine is very broad. Indeed, to date, activity has been documented against 20 different nematode, trematode and cestode species. Taken together, tribendimidine warrants further scientific inquiry, including more comprehensive toxicity appraisals, mechanism of action studies and clinical investigation as it holds promise as a broad spectrum anthelminthics. PMID:23352956

Xiao, Shu-Hua; Utzinger, Jürg; Tanner, Marcel; Keiser, Jennifer; Xue, Jian

2013-05-01

387

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, ...

388

Experimental and numerical investigation of HyperVapotron heat transfer  

International Nuclear Information System (INIS)

The divertor first wall and neutral beam injection (NBI) components of tokamak devices require high heat flux removal up to 20–30 MW m?2 for future fusion reactors. The water cooled HyperVapotron (HV) structure, which relies on internal grooves or fins and boiling heat transfer to maximize the heat transfer capability, is the most promising candidate. The HV devices, that are able to transfer large amounts of heat (1–20 MW m?2) efficiently, have therefore been developed specifically for this application. Until recently, there have been few attempts to observe the detailed bubble characteristics and vortex evolvement of coolant flowing inside their various parts and understand of the internal two-phase complex heat transfer mechanism behind the vapotron effect. This research builds the experimental facilities of HyperVapotron Loop-I (HVL-I) and Pressure Water HyperVapotron Loop-II (PWHL-II) to implement the subcooled boiling principle experiment in terms of typical flow parameters, geometrical parameters of test section and surface heat flux, which are similar to those of the ITER-like first wall and NBI components (EAST and MAST). The multiphase flow and heat transfer phenomena on the surface of grooves and triangular fins when the subcooled water flowed through were observed and measured with the planar laser induced fluorescence (PLIF) and high-speed photography (HSP) techniques. Particle image velocimetry (PIV) was selected to reveal vortex formation, the flow structure that promotes the vapotron effect during subcooled boiling. The coolant flow data for contributing to the understanding of the vapotron phenomenon and the assessment of how the design and operational conditions that might affect the thermal performance of the devices were collected and analysed. The subcooled flow boiling model and methods of HV heat transfer adopted in the considered computational fluid dynamics (CFD) code were evaluated by comparing the calculated wall temperatures with the experimentally measured values. It was discovered that the bubble and vortex characteristics in the HV are clearly heavily dependent on the internal geometry, flow conditions and input heat flux. The evaporation latent heat is the primary heat transfer mechanism of HV flow under the condition of high heat flux, and the heat transfer through convection is very limited. The percentage of wall heat flux going into vapour production is almost 70%. These relationships between the flow phenomena and thermal performance of the HV device are essential to study the mechanisms for the flow structure alterations for design optimization and improvements of the ITER-like devices' water cooling structure and plasma facing components for future fusion reactors. (paper)

389

Experimental investigation of condensation predictions for dust-enriched systems  

Science.gov (United States)

Condensation models describe the equilibrium distribution of elements between coexisting phases (mineral solid solutions, silicate liquid, and vapor) in a closed chemical system, where the vapor phase is always present, using equations of state of the phases involved at a fixed total pressure (CMAS) liquid model at T above the stability field of olivine, and the MELTS thermodynamics algorithm at lower T. Quenched high-T crystal + liquid assemblages are preserved in meteorites as Type B Ca-, Al-rich inclusions (CAIs), and olivine-rich ferromagnesian chondrules. Experimental tests of compositional regions within 100 K of the predicted T of olivine stability may clarify the nature of the phases present, the phase boundaries, and the partition of trace elements among these phases. Twenty-three Pt-loop equilibrium experiments in seven phase fields on twelve bulk compositions at specific T and dust enrichment factors tested the predicted stability fields of forsteritic olivine (Mg2SiO4), enstatite (MgSiO3), Cr-bearing spinel (MgAl2O4), perovskite (CaTiO3), melilite (Ca2Al2SiO7-Ca2Mg2Si2O7) and/or grossite (CaAl4O7) crystallizing from liquid. Experimental results for forsterite, enstatite, and grossite are in very good agreement with predictions, both in chemistry and phase abundances. On the other hand the stability of spinel with olivine, and stability of perovskite and gehlenite are quite different from predictions. Perovskite is absent in all experiments. Even at low oxygen fugacity (IW-3.4), the most TiO2-rich experiments do not crystallize Al-, Ti-bearing calcic pyroxene. The stability of spinel and olivine together is limited to a smaller phase field than is predicted. The melilite stability field is much larger than predicted, indicating a deficiency of current liquid or melilite activity models. In that respect, these experiments contribute to improving the data for calibrating thermodynamic models including MELTS.

Ustunisik, Gokce; Ebel, Denton S.; Walker, David; Boesenberg, Joseph S.

2014-10-01

390

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

Directory of Open Access Journals (Sweden)

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

Savi? Sara

2012-01-01

391

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

Science.gov (United States)

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

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

1994-01-01

392

Interleaved Carbon Minibeams: An experimental Method of Radiosurgery Developed at Brookhaven National Laboratory  

International Nuclear Information System (INIS)

Despite recent major innovations in radiation therapy and radiosurgery, there are limitations in treating certain tumors and neurological targets while assuring acceptable damage to the surrounding tissues. These encompass certain tumors in the brain, spinal cord, spinal column, and head-and-neck. This paper describes an experimental radiosurgery, “Interleaved carbon minibeams”1 being developed at the NASA Space Radiation Laboratory (NSRL), Brookhaven National Laboratory (BNL). The method uses arrays of parallel, thin (?0.3 mm incident beam thickness) planes of carbon ion beams, called carbon minibeams, that “interleave” to produce a solid radiation field at the target . Therefore, the method delivers a solid field of carbon radiation to the target while exposing the surrounding tissues to single arrays of carbon minibeams, which are well tolerated by tissues

393

Experimental investigation of electron beam wave interactions utilising short pulses  

International Nuclear Information System (INIS)

Experiments have investigated the production of ultra-short electromagnetic pulses and their interaction with electrons in various resonant structures. Diagnostic systems used in the measurements included large bandwidth detection systems for capturing the short pulses. Deconvolution techniques have been applied to account for bandwidth limitation of the detection systems and to extract the actual pulse amplitudes and durations from the data. A Martin-Puplett interferometer has been constructed for use as a Fourier transform spectrometer. The growth of superradiant electromagnetic spikes from short duration (0.5-1.0 ns), high current (0.6-2.0 kA) electron pulses has been investigated in a Ka-band Cherenkov maser and Ka- and W-band backward wave oscillators (BWO). In the Cherenkov maser, radiation spikes were produced with a peak power ? 3 MW, a duration ? 70 ps and a bandwidth ? 19 %. It is shown that coherent spontaneous emission from the leading edge of the electron pulse drives these interactions, giving rise to self-amplified coherent spontaneous emission (SACSE). BWO spikes were produced with a peak power ? 63 MW and a pulse duration ? 250 ps in the Ka-band and ? 12 MW and ? 170 ps in the W-band. Evidence of superradiant evolution has been observed in the measurements of scaling laws such as power scaling with the current squared and duration scaling inversely with the fourth root of the power. An X-band free-electron maser amplifier, in which a shoer amplifier, in which a short (1.0ns) injected radiation pulse interacts with a long (? 140 ns) electron beam, has been investigated. The interaction is shown to evolve in the linear regime. The peak output power was 320 kW, which corresponded to a gain, approximately constant across the band, of 42 dB. Changes to the spectrum, that occur when the input radiation pulse is injected into electrons with an energy gradient, have been analysed. (author)

394

Experimental investigation on the preferential erosion of biochar  

Science.gov (United States)

The influence and effect of biochar on soil properties has been intensively investigated, particularly in the context of its potential to sequester carbon and mitigate the effects of anthropogenic climate change. One major question that remains unanswered concerns the erodibility and fate of biochar in the landscape. Since biochar has a lower bulk-density than soil, preferential erosion of biochar is most likely. However, until now, almost no actual data on the enrichment of biochar in in the eroded sediment or the net loss from fields exist. This important gap of knowledge could have profound economic implications for farmers committed to its use, since a high net annual loss of biochar by erosion could exceed any net annual economic gain. Most importantly, any positive gain for the environment largely depends on the amount of biochar that remains within the upper soil matrix. The overall objective of this study was to explicitly investigate the erodibility of biochar, if erosion events occur directly or soon after its application. I this way, the financial value of the eroded biochar and its cost-effectiveness, if applied to whole field scales, could be estimated. The test site is located near Viborg in north Jutland, Denmark. Biochar was applied to the soil surface of three plots on a recently cultivated sandy field at concentrations equivalent to 1.5-2.0 kg m-2 and manually incorporated within the till-zone. Three consecutive 30 min. erosion simulations were conducted on each plot using the 2.2 m-2 Portable Wind and Rainfall Simulator. The preliminary results of this study showed that a fair amount of biochar can be eroded from the fields within the first rainfall events after biochar application to the soil. In order to provide guidelines for its application and post-application management to reduce the erodibility and net discharge of biochar from fields, further investigations are needed.

Fister, Wolfgang; Heckrath, Goswin; Greenwood, Philip; Kuhn, Nikolaus J.

2013-04-01

395

Experimental investigation of the crashworthiness of scaled composite sailplane fuselages  

Science.gov (United States)

The crash dynamics and energy absorption of composite sailplane fuselage segments undergoing nose-down impact were investigated. More than 10 quarter-scale structurally similar test articles, typical of high-performance sailplane designs, were tested. Fuselages segments were fabricated of combinations of fiberglass, graphite, Kevlar, and Spectra fabric materials. Quasistatic and dynamic tests were conducted. The quasistatic tests were found to replicate the strain history and failure modes observed in the dynamic tests. Failure modes of the quarter-scale model were qualitatively compared with full-scale crash evidence and quantitatively compared with current design criteria. By combining material and structural improvements, substantial increases in crashworthiness were demonstrated.

Kampf, Karl-Peter; Crawley, Edward F.; Hansman, R. John, Jr.

1989-01-01

396

Experimental investigation of friction on low-temperature ice  

International Nuclear Information System (INIS)

Using a unique technique, we formed a thin layer of ice on steel surface at temperature as low as 123 K in an ultra-high vacuum. We investigated the frictional behavior of such a thin ice layer in the same UHV using a pin-on-disk friction tester. The sample surfaces were monitored in situ using X-ray Photoelectron Spectroscopy (XPS). Testing data showed that the friction coefficient was a linear function of temperature. This study indicates that the sliding motion is lubricated by a frictionally melted liquid layer

397

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

398

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

Science.gov (United States)

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

Sharon E Lynn (The College of Wooster Biology)

2007-12-01

399

Experimental investigation of sodium bentonite stability in Hanford basalt  

International Nuclear Information System (INIS)

Sodium bentonite is a candidate material for the waste package backfill component in a repository in basalt at the Hanford Site. Preliminary hydrothermal experiments have been conducted under near-field geochemical conditions expected to occur in the reference repository location in Grande Ronde Basalt. Experiments have been conducted in the basalt/groundwater, bentonite/groundwater, and basalt/bentonite/groundwater systems. The experiments have been conducted at 3000C using a simulated Grande Ronde groundwater, reference Umtanum basalt, and sodium bentonite. Key data generated by the experiments include experimental solution analyses as a function of time and preliminary solids analysis by scanning transmission electron microscopy and x-ray diffraction. Solution trends of the major aqueous species were similar in the three systems and are characterized by: (1) the gradual reduction of the pH value from approx.9.75 to a steady-state value of approx.6, (2) an initial rapid increase followed by a gradual decreasein silica concentration, and (3) a slight or negligible increase in sodium, sulfate, and chloride concentrations. In the bentonite/groundwater experiment, small amounts (0C under hydrothermal conditions in basalt>C under hydrothermal conditions in basalt to permit its use as a backfill material

400

Experimental Investigation of Moisture Driven Fracture in Solid Wood  

DEFF Research Database (Denmark)

Solid timber products, containing both heartwood and sapwood, often have a high tendency to crack during the drying process. This can cause severe loss of material for the saw-mills, especially for products with large cross sectional dimensions. The cracks (e.g. end-cracks) arise, in some cases, early in the drying process and close again later in the process. It can be difficult to see the closed cracks with visual grading. This may result in too high grading of the damaged material which may cause problems for customers such as building and furniture industries. Moisture content (MC) in green wood varies within the cross section of a timber log. The MC of heartwood, for example, is considerable lower than the MC of sapwood. Shrinkage starts at different times within different parts of the cross section, which results in a complex state of strains and stresses. The moisture related crack pattern in wood often becomes quite complex because of the annual ring structure and the different MC levels within heartwood and sapwood. The focus of this work represents the cross sectional behaviour of a timber log. The main aim is to accumulate experimental results and data for the development of a finite element model to evaluate the various couplings in the hygro-mechanical problem that govern moisture driven cracking in wood.

Larsen, Finn; Ormarsson, Sigurdur

2010-01-01

401

Experimental investigation on ejecting low-temperature cooling superconducting magnets  

Energy Technology Data Exchange (ETDEWEB)

Highlights: • The cooling temperature of the superconducting materials can be adjusted by the ejecting refrigeration. • The result shows that the temperature of liquid nitrogen can be reduced to 70 K by controlling the inlet water pressure of the ejector. • The refrigeration performance of ejector is affected by the different structure and system pressure. -- Abstract: With the development of the high-temperature superconducting (HTS) materials and refrigeration technologies, using ejecting refrigeration to cool the superconducting materials becomes the direction of HTS applications. In this paper, an experimental study has been carried out on the basis of the theory of analyzing the ejecting low-temperature cooling superconducting magnet. The relationship between area ratios and refrigeration performance at different system pressures was derived. In addition, the working fluid flow and suction chamber pressure of the ejector with different area ratios at various inlet pressures have been examined to obtain the performance of ejectors under different working conditions. The result shows that the temperature of liquid nitrogen can be reduced to 70 K by controlling the inlet water pressure when the pressurized water at 20 °C is used to eject the saturated liquid nitrogen, which can provide the stable operational conditions for the HTS magnets cooling.

Liu, Bin; Zhang, Qiang, E-mail: 6266798@qq.com; Tong, Ming-wei; Hu, Peng; Wu, Shuang-ying; Cai, Qin; Qin, Zeng-hu

2013-10-15

402

Experimental Investigation of Influences of Roughness Receptivity on Protuberance Noise  

Science.gov (United States)

When a two-dimensional protuberance is set in a laminar boundary layer, tonal sound is radiated through a feedback-loop mechanism between sound radiation from the protuberance and generation of Tollmien–Schlichting (T–S) waves in the receptivity region. In this paper, influences of a small-height roughness glued upstream of the protuberance on the feedback mechanism were examined experimentally in a zero-pressure-gradient laminar boundary layer at low Mach numbers. The results showed that depending on the location and height of roughness, competition between leading-edge-generated and roughness-generated T–S waves occurred and consequently governed sound radiation. Even when the roughness height was on the order of one-tenth the displacement thickness, tonal sound due to the feedback-loop between the roughness and protuberance could be more dominant than that between the leading edge and protuberance. It was also shown that the roughness receptivity reduced the critical protuberance height for the occurrence of tonal sound.

Kobayashi, Masashi; Asai, Masahito

2015-01-01

403

Experimental and Computational Investigation of Hypersonic Electric-Arc Airspikes  

Science.gov (United States)

Drag reduction effects of an electric arc airspike in a hypersonic flow are currently being studied in the Rensselaer Polytechnic Institute 24-inch Hypersonic Shock Tunnel (RPI HST). In tandem these results are being modeled computationally, and compared to existing theory. The arc is driven by a high current lead-acid battery array, producing a maximum of 75-kilowatts into the self-sustaining electrical discharge. The test conditions were for Mach 10, 260 psia stagnation pressure, and 560 K stagnation temperature flow - a low enthalpy, ``ideal gas'' condition. Schlieren photographs are taken of the arc apparatus and downstream blunt body, with a variety of arc powers and source/body distances. Fast-response accelerometers are used to measure drag on the hanging blunt body. These tests are conducted with and without the arc to establish the most efficient placement and power of the airspike. The computational effort employs the Euler gasdynamic equations to represent a heat source in flow conditions and geometries identical to those tested in the RPI HST. The objective of the combined experimental/computational parametric study is to enhance understanding of the drag reduction features inherent to the airspike phenomenon.

Bracken, R. M.; Hartley, C. S.; Mann, G.; Myrabo, L. N.; Nagamatsu, H. T.; Shneider, M. N.; Raizer, Y. P.

2003-05-01

404

Experimental investigation of aerosol release behaviour from sodium pool fires  

International Nuclear Information System (INIS)

Accidental spillages of high temperature liquid sodium lead to vaporisation of sodium accompanied with fires and generation of sodium aerosols. Aerosol release rate from pool fires is an important parameter for assessing the aerosol hazard in LMFBR containments and for the design of efficient filters in ventillation systems. In the present study, small scale experiments are conducted with burning pools of liquid sodium to understand the effect of aerosol release rate on various factors such as volume flow rate and moisture content of air, burning duration of fire as well as pool depth. In all the experimental runs, nonisothermal pool conditions are set up and maximum pool temperatures are recorded. Tests related to pools of varying depths are carried out in open atmosphere with different sodium inventory (30 to 400 g.), whereas circulating atmospheres are employed for other tests with fixed mass of sodium (? 16 g). While flow rate of air, burning duration and pool depth show strong correlation towards aerosol release rate, moisture content of air has no noticeable impact on the sodium release phenomena

405

Experimental and modeling investigation on structure H hydrate formation kinetics  

International Nuclear Information System (INIS)

Highlights: • Applying affinity model for the formation kinetics of sH hydrate and two stage kinetics. • Performing the experiments of hydrate formation of sH with MCP. • A unique path for the SH hydrate formation. - Abstract: In this work, the kinetics of crystal H hydrate and two stage kinetics formation is modeled by using the chemical affinity model for the first time. The basic idea is that there is a unique path for each experiment by which the crystallization process decays the affinity. The experiments were performed at constant temperatures of 274.15, 275.15, 275.65, 276.15 and 277.15 K. The initial pressure of each experiment is up to 25 bar above equilibrium pressure of sI. Methylcyclohexane (MCH), methylcyclopentane (MCP) and tert-butyl methyl ether (TBME) are used as sH former and methane is used as a help gas. The parameters of the affinity model (Ar and tk) are determined and the results show that the parameter of (Ar)/(RT) has not a constant value when temperature changes in each group of experiments. The results indicate that this model can predict experimental data very well at several conditions

406

Design and experimental investigation of portable solar thermoelectric refrigerator  

Energy Technology Data Exchange (ETDEWEB)

The main objective of this study is to design and build an affordable solar thermoelectric refrigerator for the Bedouin people (e.g. deserts) living in remote parts of Oman where electricity is still not available. The refrigerator could be used to store perishable items and facilitate the transportation of medications as well as biological material that must be stored at low temperatures to maintain effectiveness. The design of the solar-powered refrigerator is based on the principles of a thermoelectric module (i.e., Peltier effect) to create a hot side and a cold side. The cold side of the thermoelectric module is utilized for refrigeration purposes; provide cooling to the refrigerator space. On the other hand, the heat from the hot side of the module is rejected to ambient surroundings by using heat sinks and fans. The designed solar thermoelectric refrigerator was experimentally tested for the cooling purpose. The results indicated that the temperature of the refrigeration was reduced from 27 C to 5 C in approximately 44 min. The coefficient of performance of the refrigerator (COP{sub R}) was calculated and found to be about 0.16. (author)

Abdul-Wahab, Sabah A.; Al-Habsi, Is' haq A.; Al-Rubai' ey' , Hilal S.; Al-Battashi, Abdulaziz K.; Al-Tamimi, Ali R.; Al-Mamari, Khamis H. [Sultan Qaboos University, College of Engineering, Mechanical and Industrial Engineering Department, P.O. Box 33, Al Khoud P.C. 123, Muscat (Oman); Elkamel, Ali; Chutani, Muhammad U. [Department of Chemical Engineering, University of Waterloo, 200 University Avenue Wes, Waterloo, Ontario (Canada); Al-Damkhi, Ali M. [Department of Environmental Sciences, College of Health Sciences, Public Authority for Applied Education and Training (PAAET) (Kuwait)

2009-01-15

407

Applicability of laboratory experimental data (solubilities and sorption coefficients) to natural aquifier systems, for example, the Gorleben aquifer system  

International Nuclear Information System (INIS)

The main objective of the research project is to elucidate the migration behaviour of long-lived radionuclides, especially actinides and technetium, in natural aquifer systems. Particular emphasis is directed to answer the question whether or not the experimental data obtained in laboratory can be applied without restriction to natural aquifer systems. For this purpose, the Gorleben aquifer system is taken as an example. As the subject encompasses a wide variety of geochemical reactions of long-lived radionuclides of divers elements, experiments have been confined to notable examples selected with regard to chemical nature of each element. Common reactions of geochemical importance, which are not well or poorly understood in the literature, are given priority in the present investigation. Laboratory experiments have been conducted on hydrolysis, carbonate complexation, humate complexation, redox reaction and colloid generation. Column experiments were performed for the elucidation of the migration behaviour of colloid-borne actinides. The applicability of laboratory data has been examined by comparison of thermodynamic speciation with direct spectroscopic speciation for given actinides in natural aquatic solution. Whenever the colloid generation is involved, either formation of 'real' or 'pseudo' colloids, the application of thermodynamic speciation becomes failed. In this case a new approach to appraisal of the actinide migration behaviour appears indispensable. Thistion behaviour appears indispensable. This fact has aspired us to develop a novel method for the quantification of aquatic colloids of nanosize (10-100 nm) in very dilute concentrations (ppt range). (orig.)

408

Experimental investigation of zero phase shift effects for Coriolis flowmeters due to pipe imperfections  

DEFF Research Database (Denmark)

Theoretical investigations of a single, straight, vibrating, fluid-conveying pipe have resulted in simple analytical expressions for the approximate prediction of the spatial shift in vibration phase. The expressions have lead to hypotheses for real Coriolis flowmeters (CFMs). To test these, the flexural vibrations of two bent, parallel, non-fluid-conveying pipes are studied experimentally, employing an industrial CFM. Special attention has been paid on the phase shift in the case of zero mass flow, i.e. the zero shift, caused by various imperfections to the ‘‘perfect’’ CFM, i.e. non-uniform pipe damping and mass, and on ambient temperature changes. Experimental observations confirm the hypothesis that asymmetry in the axial distribution of damping will induce zero shifts similar to the phase shifts due to fluid flow. Axially symmetrically distributed damping was observed to influence phase shift at an order of magnitude smaller than the primary effect of mass flow, while small added mass and ambient temperature changes induced zero shifts two orders of magnitude smaller than the phase shifts due to mass flow. The order of magnitude of the induced zero shifts indicates that non-uniform damping, added mass as well as temperature changes could be causes contributing to a time-varying measured zero shift, as observed with some commercial CFMs. The conducted experimental tests of the theoretically based hypotheses have shown that simple mathematical models and approximate analysis allow general conclusions, that may provide a direct insight, and help increasing the benefit of time consuming numerical simulations and laboratory experiments.

Enz, Stephanie; Thomsen, Jon Juel

2011-01-01

409

Experimental investigation of a box type solar cooker employing a non-tracking concentrator  

Energy Technology Data Exchange (ETDEWEB)

The present work aims at development of a box type solar cooker utilizing non-tracking concentrator optics to enhance the solar energy availability in the box of the cooker for efficient cooking. A laboratory model of a box type solar cooker employing a non-tracking concentrator has been designed and fabricated, and its thermal performance has been investigated experimentally. The concentrator, consisting of two planar reflectors suitably positioned in an east-west configuration on an inclined framework, is mounted on the box of the cooker to reflect incident solar radiation on the base absorber of the cooker. The design angle of inclination of the framework is taken equal to the latitude of the location and it is adjusted seasonally. The thermal performance of the experimental solar cooker has also been compared with that of a conventional box type solar cooker whose dimensions and make are identical to the box used with the former and which was also tested simultaneously under similar solar insolation and ambient conditions. The experimental results obtained show that the concentrator solar cooker provides a stagnation temperature 15-22{sup o}C higher than that of the conventional box type solar cooker using a booster mirror. It is also observed that the boiling point of water with the concentrator cooker is reached faster, by 50-55 min, than with the conventional box type cooker using a booster mirror. Thus, the solar cooker utilizing non-tracking reflectors provides increased heat collection and faster cooking compared to the conventional box type cooker. The results of the tests conducted have been analyzed and discussed. (author)

Negi, B.S. [Government of India, New Delhi (India). Solar Energy Centre; Purohit, I. [Indian Institute of Technology, New Delhi (India). Centre for Energy Studies

2005-03-01

410

EXPERIMENTAL INVESTIGATION OF RELATIVE PERMEABILITY UPSCALING FROM THE MICRO-SCALE TO THE MACRO-SCALE  

Energy Technology Data Exchange (ETDEWEB)

The principal challenge of upscaling techniques for multi-phase fluid dynamics in porous media is to determine which properties on the micro-scale can be used to predict macroscopic flow and spatial distribution of phases at core- and field-scales. The most notable outcome of recent theories is the identification of interfacial areas per volume for multiple phases as a fundamental parameter that determines much of the multi-phase properties of the porous medium. A formal program of experimental research was begun to directly test upscaling theories in fluid flow through porous media by comparing measurements of relative permeability and capillary-saturation with measurements of interfacial area per volume. This project on the experimental investigation of relative permeability upscaling has produced a unique combination of three quite different technical approaches to the upscaling problem of obtaining pore-related microscopic properties and using them to predict macroscopic behavior. Several important ''firsts'' have been achieved during the course of the project. (1) Optical coherence imaging, a laser-based ranging and imaging technique, has produced the first images of grain and pore structure up to 1 mm beneath the surface of the sandstone and in a laboratory borehole. (2) Woods metal injection has connected for the first time microscopic pore-scale geometric measurements with macroscopic saturation in real sandstone cores. (3) The micro-model technique has produced the first invertible relationship between saturation and capillary pressure--showing that interfacial area per volume (IAV) provides the linking parameter. IAV is a key element in upscaling theories, so this experimental finding may represent the most important result of this project, with wide ramifications for predictions of fluid behavior in porous media.

Laura J. Pyrak-Nolte; Nicholas J. Giordano; David D. Nolte

2004-03-01

411

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

412

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

Science.gov (United States)

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

Everhart, Roger

413

Experimental Investigation of Drilling Fluid Performance as Nanoparticles  

Directory of Open Access Journals (Sweden)

Full Text Available In this work, a drilling fluid recipe has been developed by using nanoparticles, to increase the efficiency of drilling operations for maximum accessibility to new & matured oil reserves and suited to various drilling conditions. The solution to severe drilling problems like pipe sticking, lost circulation, formation damage, erosion of borehole, thermal instability of drilling fluids and insufficient gel properties of the drilling fluids, lies in controlling and optimizing the rheology of the drilling fluid. The inefficiency of the drilling fluid in performing certain functions is mainly due to a lack in a particular rheological property. The performance of the clay composites water-based bentonite drilling mud in terms of its rheological behavior in drilling systems was investigated at various pressures and temperatures. It was found that temperature had a detrimental effect on the rheological properties. The behavior was investigated using synthesized nano bentonite water based drilling fluid. The fluid retained all the desired rheological properties at elevated temperatures and pressures, thus enhanced the possibility of its application in deep wells, where elevated temperatures and pressures were quite common.

Jamal Nasser

2013-09-01

414

Experimental investigation on heat transport in gravel-sand materials.  

DEFF Research Database (Denmark)

The project is a basic study on the expected thermal behaviour of gravel storage initiated as a part of a research and demonstration gravel storage for seasonal heat storage.The goal of the investigation is to determine the heat transfer between heat pipes and sand-gravel storage media by carrying out in a small size experiment. The experiment consists of a highly insulated box filled with two kinds of sand material crossed by a plastic heat pipe. Heat transfer is measured under dry and water satured conditions in a cross-section.The conclusions are clear. To obtain necessary heat conduction in sand-gravel material, the storage media is to be water satured. In this case, handling of such material on site is rather complex. The conduction is highly dependent on the thermal properties of the storage media and so is the overall thermal performance of a storage applying such media. For sandy media no convectional heat transport is found. It would be relevant to extend the investigation to media that enables convectional heat transport. A last conclusion is that such experiments, necessary for proper designing of sand-gravel storage types, are a very cheap form of collecting information about the expected behaviour of large storage systems.

Maureschat, Gerald; Heller, Alfred

1997-01-01

415

Experimental investigations on single stage modified Savonius rotor  

Energy Technology Data Exchange (ETDEWEB)

Conventional Savonius or modified forms of the conventional Savonius rotors are being investigated in an effort to improve the coefficient of power and to obtain uniform coefficient of static torque. To achieve these objectives, the rotors are being studied with and without central shaft between the end plates. Tests in a closed jet wind tunnel on modified form of the conventional Savonius rotor with the central shaft is reported to have a coefficient of power of 0.32. In this study, modified Savonius rotor without central shaft between the two end plates is tested in an open jet wind tunnel. Investigation is undertaken to study the effect of geometrical parameters on the performance of the rotors in terms of coefficient of static torque, coefficient of torque and coefficient of power. The parameters studied are overlap ratio, blade arc angle, aspect ratio and Reynolds number. The modified Savonius rotor with an overlap ratio of 0.0, blade arc angle of 124 and an aspect ratio of 0.7 has a maximum coefficient of power of 0.21 at a Reynolds number of 1,50,000, which is higher than that of conventional Savonius rotor (0.19). Correlation is developed for a single stage modified Savonius rotor for a range of Reynolds numbers studied. (author)

Kamoji, M.A.; Kedare, S.B. [Energy Science and Engineering Department, Indian Institute of Technology, Bombay, Powai, Mumbai - 4000 76 (India); Prabhu, S.V. [Department of Mechanical Engineering, Indian Institute of Technology, Bombay, Powai, Mumbai - 4000 76 (India)

2009-07-15

416

Experimental investigation on alteration of bentonite by concrete pore fluids  

International Nuclear Information System (INIS)

As one of application examinations of bentonite for geological disposal, a fundamental study on long term change of its properties due to correlation to concrete was conducted. D. Savage, et.al. investigated on chemical change of bentonite by dividing dissolving reaction due to alkaline solution leached from intervals of the concrete and forming reaction of new minerals due to the dissolved substance. In order to elucidate the changing behavior of bentonite, examination due to the alkaline solution was also important, and then following investigations were conducted as a dissolving test due to the alkaline solution and a test of reaction product minerals in the alkaline solution. The changing behavior of bentonite was conducted by a heated acceleration test using a model solution of an interval solution of concrete. As a result, it was found that solubility of bentonite increased extremely with increase of pH over 11. A dissolving rate constant and activation energy were obtained at each pH. And, a mixed layer mineral, CSH, CAH, and so forth were found as reaction products, which increased with increase of pH and temperature. These results were useful for analysis of long term change of the bentonite, and suggested to necessity to use the concrete with pH as low as possible. (G.K.)

417

Experimental investigation of the IFMIF target mock-up  

International Nuclear Information System (INIS)

The international fusion materials irradiation facility (IFMIF) lithium neutron target mock-ups have been constructed and tested at water and lithium test facilities in the IPPE of Russia. Jet velocity in both mock-ups was up to 20 m/s. Calculations and experiments showed lithium flow instability at conjunction point of straight and concave sections of the mock-up back wall. Water velocity profile across the mock-up width, jet thickness, and wave height were measured. The significant increase of thickness of both water and lithium jets near the mock-up sidewalls was observed. The influence of shape of the nozzle outlet part on jet stability was investigated. Lithium evaporation from the jet free surface was investigated as well as lithium deposition on vacuum pipe walls of the target mock-up. It was shown that these phenomena are not very critical for the target efficiency. The possibility of lithium denitration down to 2 ppm (at 10 ppm requested) by means of aluminium getter was shown. Two types of cold traps and plug indicators of impurities were tested. The results are presented in the paper.

418

Sediment transport during flash flood events on an intermittent river: an experimental laboratory study.  

Science.gov (United States)

Flash floods have a number of impacts on the water quality of river systems because the later is the resultant of pollutant input into the river and its transformation along its course. In the case of intermittent rivers this impact is increased by the long drought periods that usually precede such floods. Indeed, the pollutants are known to accumulate in the dry river sediments during the drought period and are flushed away by the first floods. The Vène, a small experimental catchment (67 km²) located in southern France is a perfect example of this type of behavior. The field data collected on the catchment since 1994 through routine and flood monitoring clearly show an increase in suspended solids and nutr