Science.gov (United States)

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Science.gov (United States)

... within an accuracy of +5 psig. 2. Starting Pressure and Diffuser Geometra Preliminary, tests indicated that the geometry suggested by Ref. ...

Science.gov (United States)

... turbine blade heat-transfer and study the heat-transfer augmentation in idealized geometry and its ... responsible for heat transfer augmentation. ...

Energy Technology Data Exchange (ETDEWEB)

The high-speed direct-injection diesel engine for passenger cars has been a resounding success in the marketplace in the last few years. This was due to an intensive development process as a result of which the direct-injection diesel engine for passenger cars is currently setting new standards with regard to performance and fuel consumption in spite of the constant tightening of emission regulations. Of particular importance in this context is exhaust gas recirculation (EGR). This technology permits a considerable reduction in nitrogen oxide emissions, which are especially critical in the case of the direct-injection diesel engine. In addition, continuing development of supercharging technology, in particular the turbocharger with variable turbine geometry, have allowed further improvement of the full-load behaviour and the engine response and a considerable reduction in the fuel consumption of direct-injection diesel ...

British Library Electronic Table of Contents (United Kingdom)

In this study, the effects of channel surface wettability, cross-sectional geometry and orientation on the two-phase flow in parallel gas channels of proton exchange membrane fuel cells (PEMFCs) are investigated. Ex situ experiments were conducted in flow channels with three different surface wettability (hydrophilically coated, uncoated, and hydrophobically coated), three cross-sectional geometries (rectangular, sinusoidal and trapezoidal), and two orientations (vertical and horizontal). Flow pattern map, individual channel flow variation due to maldistribution, pressure drop and flow visualization images were used to analyze the two-phase flow characteristics. It is found that hydrophilically coated gas channels are advantageous over uncoated or slightly hydrophobic channels regarding un...

International Nuclear Information System (INIS)

A nodal integral method is derived for the monoenergetic, steady-state, fixed source neutron diffusion equation in hexagonal geometry based on a coordinate transformation that maps a parallelogram into a rectangle. The new hexagonal nodal diffusion method is implemented in the computer code HND where the discrete-variable equations are solved via an iterative scheme. Because the new method's equations are derived for a rhombus, they can be solved on a sequence of embedded meshes to study the method's error order. Indeed a preliminary numerical error analysis reveals a second-order error in the mesh size, and comparison with finite difference results obtained with the finite difference based BOLD-VENTURE code indicate the superior accuracy of our new nodal method.

Energy Technology Data Exchange (ETDEWEB)

The Department of Energy has proposed a rulemaking process to set minimum standards for the efficiency of gas ranges under the National Appliance Energy Conservation Act (NAECA). The Gas Research Institute is compiling information on annual household range gas usage in order to prepare a response to the proposed rulemaking. The data base from the Northern Illinois Gas residential load study provides recent information (data taken from 1990 through 1992) over a comprehensive study of household types and appliance and user characteristics (150 variables noted for each household). The stated Objective is to study the Northern Illinois Gas residential load study data base and to evaluate its effectiveness in predicting annual household gas usage.

International Nuclear Information System (INIS)

Results of ongoing research project at the McMaster Nuclear Reactor Facility on real-time neutron radiography for the visualization of interfacial geometry, movements and phase distributions in gas-liquid and gas-liquid-metal multi-phase flows are presented. Experiments were conducted with bubble column tubes with boiling liquid nitrogen, air-water and air-mercury mixtures. Discussions are also focused on air-water flowing within a tube containing a CANDU type 37 rod fuel bundle assembly positioned both horizontally and vertically. Computer processing using a digital image format to enhance the real-time images was used. Imaging techniques include frame averaging, background substraction, edge enhancement (spatial filtering), contrast enhancement and video densitometry. (orig.).

Science.gov (United States)

The report gives results of a pilot-plant study of the ammonia absorption/ammonium bisulfate regeneration process for removing SO2 from the stack gas of coal-fired power plants. Data were developed on the effects of such operating variable in the absorption of SO2 by ammoniacal l...

Energy Technology Data Exchange (ETDEWEB)

Experimental investigations have been conducted to determine two-phase natural circulation interfacial parameters by real-time neutron radiography. The natural circulation loop used in the present experiments consists of a vertical two-phase section, a gas liquid separator, and a gas injection/heating section. Experiments were performed in a neutron beam for visualization using realtime neutron radiography system. The natural circulation was initiated by injection of known gas flow rate in the heated section. Two-phase flow interfacial parameters including interfacial geometry and phase velocities etc. for bubbly flow and slug flow patterns observed in the experiments will be given in detail. The results indicate that while the natural circulation is largely as expected and that steady stable flows are possible, there are some local phenomena that introduce instabilities due to the interfacial phenomena ...

International Nuclear Information System (INIS)

With the help of heat balance equation and high temperature thermodynamic function, the calibration relation of jet temperature with discharge power, gas flow rate was obtained for nitrogen thermal plasma. It was shown that the results were agreed with the principle of similarity. The jet temperature was a function of Peff/f, instead of a general two variables function of Peff and f, which were effective discharge power and working gas flow rate, respectively. A related discussion has been given; it will be referable to thermal plasma applications. (authors)

International Nuclear Information System (INIS)

A numerical investigation of the mixing of gaseous uranium and hydrogen inside an open-cycle gas core nuclear rocket engine (spherical geometry) is presented. The gaseous uranium fuel is injected near the centerline of the spherical engine cavity at a constant mass flow rate, and the hydrogen propellant is injected around the periphery of the engine at a five degree angle to the wall, at a constant mass flow rate. The main objective is to seek ways to minimize the mixing of uranium and hydrogen by choosing a suitable injector geometry for the mixing of light and heavy gas streams. Three different uranium inlet areas are presented, and also three different turbulent models (k-var-epsilon model, RNG k-var-epsilon model, and RSM model) are investigated. The commercial CFD code, FLUENT, is used to model the flow field. Uranium mole fraction, axial mass flux, and radial mass flux contours are obtained. ...

Energy Technology Data Exchange (ETDEWEB)

The shrinking core model is examined for gas-solid noncatalytic reactions with a self-inhibited rate form and it is shown that multiple reaction pathways are possible for solid particles reacted under identical conditions. The observed reaction rate can have up to two discontinuities (jumps) during reaction for particles of spherical and cylindrical shape. The geometric instability analysis reveals that the reaction interface is stable under a very limited set of conditions only for solid particles of slab geometry. For a sphere or cylinder at large Biot numbers the reaction interface is always potentially unstable. This model provides a plausible explanation for gas-solid reactions which exhibit erratic shrinking core behavior.

Energy Technology Data Exchange (ETDEWEB)

Grout has been evaluated as a means of containing low-level radioactive waste for long-term disposal. Concerns about hydrogen and reactive gas generation in the Hanford Site grout disposal facility lead to the development of the G3 model, which has predicted buildup of radiolytically formed gases in the grout region and their migration to air-filled regions. The G3 model is a one-dimensional code that couples models of gas diffusion with two-phase gas and liquid flow. It was coupled to a compartment diffusion model and these models predicted the concentrations of hydrogen I nitrous oxide, and other gases in air-filled regions of the grout disposal facility. The results have served as the technical basis for safety studies. A unique finding of the G3 model was that a liquid return, or expulsion of unbound liquid from the grout region, could occur. This liquid return is driven by displacement caused by ...

Energy Technology Data Exchange (ETDEWEB)

The influence of engine operating variables on the performance, emissions and heat release in a compression ignition engine operating in normal diesel and dual-fuel modes (with natural gas fuelling) was investigated. Substantial reductions in NO{sub x} emissions were obtained with dual-fuel engine operation. There was a corresponding increase in unburned hydrocarbon emissions as the substitution of natural gas was increased. Brake specific energy consumption decreased with natural gas substitution at high loads but increased at low loads. Experimental results at fixed pilot injection timing have also established the importance of intake manifold pressure and temperature in improving dual-fuel performance and emissions at part load. (Author)

Energy Technology Data Exchange (ETDEWEB)

This paper describes the derivation of a new equation that can be used to model the permeability behavior of a fractured, sorptive-elastic media, such as coal, under variable stress conditions commonly used during measurement of permeability data in the laboratory. The model is derived for cubic geometry under biaxial or hydrostatic confining pressures. The model is also designed to handle changes in permeability caused by adsorption and desorption of gases from the matrix blocks. The model equations can be used to calculate permeability changes caused by the production of methane from coal as well as the injection of gases, such as carbon dioxide, for sequestration in coal. Sensitivity analysis of the model found that each of the input variables can have a significant impact on the outcome of the permeability forecast as a function of changing pore pressure; thus, accurate input data are essential. The permeability model ...

Energy Technology Data Exchange (ETDEWEB)

This article describes the state-of-the-art HVAC system at the Philadelphia Marriott Hotel. Thermal comfort and indoor air quality are emphasized. The system uses a hybrid gas absorption/electric centrifugal chilled water plant, variable flow pumping, water-side economizers to provide free cooling, central air handling units with air-side economizers and flow monitoring equipment.

British Library Electronic Table of Contents (United Kingdom)

The adsorption of benzyl alcohol and 1-phenylethanol on graphitized thermal carbon black at 300 K is investigated. Thermodynamic characteristics of the adsorption of conformers stable in the gas phase and in the adsorbed state are determined by a molecular statistics method. The geometry of the molecules is optimized using the MP2 and B3LYP methods with a 6-311++G(d,p) basis set. Using the PBE0/6-31G(d) method, it is established that, in the adsorption of benzyl alcohol, two types of interactions, CH?O and OH??GTCB, occur. It is shown that, in 1-phenylethanol, intramolecular interactions are maintained.

International Nuclear Information System (INIS)

Engineering details of a high voltage driven corona-plasma ozone generator are described. The plasma diode of generator has coaxial cylindrical geometry with cathode located inside anode. Cathode is made of a large number of radial gas nozzles arranged on central tubular mast which admits oxygen gas. The sharp endings of the nozzles along with a set of corona rings create the high electric field at the cathode required for formation of dense corona plume responsible for O_3 evolution. A model of coronal plasma generation and ozone production is presented. The plasma formation is strongly dependent on the electric field and temperature in side diode where a high electron density in a low temperature negative corona is suited for high ozone yields. These are established by suitable regulation of A-K gap, voltage, oxygen pressure, and cathode-nozzle population.

Energy Technology Data Exchange (ETDEWEB)

This report introduces a microprocessor system composed of a Z-80 single-board computer controlling a gas-carburizing process. The system has 7 analogical input and output signals 24 switch signal-input and 12 switch signal-output signals, which are applicable for temperature, carbon potential, and mechanical-movement control of multipurpose sealed furnaces, or for mutiple-zone temperature, carbon potential, and mechanical-movement control of continuous gas carburizing furnaces; or for distributed control of pit-type carburizing furnaces. The setpoints of variables, such as treating time, temperature, carbon potential of carburizing period, carbon potential of diffusion period, depth of carburizing layer, P.I.D. etc., are entered by keyboard and stored into memories, and actual values are displayed by digital tubes. Furthermore, the fault of thermocouple, oxygen probe, or infrared CO/sub 2/ analyzer; carbon potential, or ...

Energy Technology Data Exchange (ETDEWEB)

Flame lengths inside circular tubes, using an (in-shot) atmospheric burner design commonly found in gas-fired residential furnaces were visually observed for natural gas and air under various operating conditions. The flame length data were reduced into dimensionless flame lengths, which were shown to be linearly proportional to the Peclet number of the fuel and air mixture. The dimensionless flame length dependence reported does not scale according to the classical flame models: pre-mixed (laminar) flame or diffusion flame. Instead, the flame length dependence was found to scale with the fuel burn speed, gas/mixture properties (evaluated at the adiabatic flame temperature), and flow parameters. Currently, this is the only flame length study available for the standard atmospheric burner designs commonly used in residential heating products. The results and data reduction provide an easy method to compute flame length ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

British Library Electronic Table of Contents (United Kingdom)

A dense Pd-Ag membrane reactor (MR) with 100% hydrogen selectivity packed with either Rh/La2O3 or Rh/La2O3-SiO2 as catalysts was used to carry out the dry reforming of methane. The membrane reactor simulation was performed using a well-known reactor model. For this purpose, we employed the equations derived from complete kinetic studies of the dry reforming of methane reaction in connection with both catalysts. In addition, we developed the kinetic equation for the reverse water gas shift reaction (RWGS). The combination of detailed kinetic studies with the measured permeation flux for the Pd-Ag membrane allowed a complete comparison between experimental and simulated operation variables. The variables studied for both catalysts were methane conversion and hydrogen permeation as a function...

Energy Technology Data Exchange (ETDEWEB)

A brief description of a method for producing relatively intense molecular negative ion beams for the difficult Group IIA elements is given which offers considerable improvement in terms of source operation and beam intensity stability over other methods conventionally utilized. It is particularly suited for use in cesium plasma sources such as the Aarhus geometry and axial geometry versions of the source. The method utilizes H/sub 2/ source feed gas for the production of a hydrogen-rich plasma discharge which sputters a negatively biased probe made of elemental or copper alloy material. Negative ion beams of MgH/sub 3//sup -/>=12 ..mu.. A have been realized during routine operation of the 25 MV tandem accelerator. Negative ion beam intensity data, typical source operational parameters, and examples of mass spectra associated with their production are given. Interesting intermetallic molecular negative ion beams ...

Energy Technology Data Exchange (ETDEWEB)

Density is useful in deducing the spatial structure of coals. In this paper, nitrogen has been used instead of the commonly employed helium, for the gas displacement pycnometer based density determination of a number of coals of Indian origin. The results show that the nitrogen-based densities are always higher than the helium-based ones. Also, empirical relationships between the helium-based and nitrogen-based coal densities have been developed by two modeling methods, namely, multi-variable regression and artificial neural networks. Although the two models have fared well, the neural network model exhibits a relatively better prediction accuracy and generalization performance than the regression model. This study thus demonstrates that nitrogen, which is cheaper and easily available, can be used gainfully as the probe gas for estimating the true density of coals. 23 refs., 1 fig., 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

In the present work, the process of carbon dioxide absorption is analyzed at high partial pressures, in aqueous solutions of 1-amino-2-propanol (monoisopropanolamine (MIPA)), in relation to the thermal effects involved. All experiments were made in a stirred-tank reactor with a plane unbroken gas-liquid interface. The variables considered were the MIPA concentration within the range 0.1--2.0 M and the temperature within the interval 288--308 K. From the results, the authors deduce that the absorption process takes place in the nonisothermal instantaneous regime and propose an equation which not only relates the experimental results of flow density with the initial concentration of amine but at the same time enables the evaluation of the rise in temperature in the gas-liquid interface.

International Nuclear Information System (INIS)

A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the plasma source are measured using absorption spectroscopy and electro-chemical NO-detector at ...

Science.gov (United States)

Shape optimization of heat transfer augmentation device employed in turbine blade internal cooling passage has been performed numerically using single as well as multi-objective optimization procedures. Polynomial response surface approximation method and multi-objective genetic algorithm are used for single and multi-objective optimizations, respectively. Problem to enhance heat transfer rate considering staggered dimples on single surface of cooling passage has been formulated, and Reynolds-averaged Navier-Stokes equations are solved to analyze the flow field and the heat transfer. Three design variables defining channel and dimple dimensions, and two objective functions related to Nusselt number and friction drag are employed. Latin hypercube sampling is used to generate sampling points in design space, and the evaluated objectives are used to generate a set of optimal designs. Optimal shapes show higher heat transfer rates in the case of lower channel height, ...

International Nuclear Information System (INIS)

This paper describes a series of tests investigating two-phase flow regimes in a transparent model of a PWR hot leg. Test conditions were selected to cover a wide range of gas and liquid superficial velocities (.01 m/s 2 m/s) were also performed for comparison with semi-analytical predictions. Results include average void fractions, flow rates, and visual characterizations of the two-phase flow phenomena. Results show generally good agreement with Taitel and Duckler flow regime map and Zuber-Findlay correlation for average void fraction in vertical pipes. Results also indicate that flow regimes and collapsed liquid level (void fraction) are more strongly dependent on air flow rate (air superficial velocity) than water flow rate (water superficial velocity).

Energy Technology Data Exchange (ETDEWEB)

The three tasks were completed during this reporting period. During this quarter, work focused on a local structural analysis of the Table Rock field, greater Green River basin (GGRB) in southwestern Wyoming. The ultimate objective of the local analysis is to apply the techniques developed and demonstrated during earlier phases of the project in the Rulison Field area of the Piceance basin for sweet-spot delineation. The primary goal of this work is to focus in on the Table Rock field area in the northern Washakie basin of the Greater Green River basin in support of Union Pacific Resources and DOE planned horizontal drilling efforts. The work plan for the quarter of April 1, 1998--June 30, 1998 consisted of three tasks: (1) Acquire necessary seismic data and depth-convert, (2) Map major fault geometry and analyze displacement vectors, (3) Develop and initiate a natural fracture prediction study.

Energy Technology Data Exchange (ETDEWEB)

The influence of common welding defects such as internal under-cut, incomplete penetration of the root bead, internal concavity and hollow bead have been evaluated in a sour environment. Tests were performed on samples cut from actual pipeline welds. The individual defects were subjected to slow strain rate testing. The samples were then examined by metallography, scanning electron microscopy, and hardness testing. It was established that a threshold stress intensity exists for sulphide stress cracking. The test results were compared to those obtained from samples of the weld and pipe which did not contain any defects. This comparison indicated that the metallurgical variations associated with the presence of a weld are the main factor for sulphide stress cracking rather than any specific defects or geometry. 5 tabs., 9 figs.

International Nuclear Information System (INIS)

To develop the advanced subchannel analysis code, the dominant factors that influence the boiling transitional process must be taken into account in the mechanistic constitutive equations based on the flow geometries and the fluid properties. The dominant factors that influence the boiling transitional processes are (1) the gas-liquid re-distribution by cross flow, (2) the liquid film dryout, (3) the two-phase flow regime transition, (4) the droplet deposition, and (5) the spacer-droplet interaction. At first, we indicated the strategy for the development of the constitutive equations for the five dominant factors based on the experimental database by the latest measurement technique and the latest computational fluid dynamics method. Then, the problems of the present constitutive equations and the improvement plan of the constitutive equations were indicated. Finally, the layered structure for the two-phase/three-field subchannel code ...

International Nuclear Information System (INIS)

Precise measurements of alpha particle counting efficiencies have been made using isotropic, infinitely thin alpha emitting sources placed in direct contact with a thin, end-window, gas flow proportional detector. Except for alpha particle absorption in the window material, this geometry approaches 2#pi#, such that the only other variation in the response of the counter is from the random decay of the source. The data are fitted to the expected linear function of count rate versus window thickness and the resulting fitting parameters are used to calculate the counting efficiencies for a given thickness of window material. Counting efficiencies for 5.31, 6.06, and 8,78 MeV alpha particles have been determined from sources of "2"1"0Po and the progeny of "2"1"2Pb. For the particular counter used, the counting efficiencies in counts per alpha and their respective relative standard deviations were 0.401 #+-# 0.12%, 0.418 #+-# 0.41%, and 0.455 #+-# ...

Energy Technology Data Exchange (ETDEWEB)

The Sperchios Basin is an active asymmetric graben, bounded to the south by a major border fault system with major fault segments typically 20-30 km long. The basin is dominated by a major axial fluvio-deltaic system which enters the partially enclosed Maliakos Gulf to the east. Lateral sourced depositional systems within the basin comprise hanging-wall and footwall-derived alluvial fans and a narrow coastal plain along the footwall scarp bordering the Maliakos Gulf. High resolution seismic data from the Maliakos Gulf reveals three late Quaternary progradational parasequences sourced from axial and lateral depositional systems, with a regional late-Pleistocene transgressive surface dated at circa. 10 ka BP within the Maliakos Gulf. Differential subsidence of the late Pleistocene transgressive surface indicates marked variation in subsidence from 2.4 m ka{sup -1} at fault segment centers to 0.8 m ka{sup -1} at segment boundaries. The geometry and internal ...

International Nuclear Information System (INIS)

The chemical composition and evolution of produced waters associated with gas production in the Palm Valley gas field, Northern Territory, has important implications for issues such as gas reserve calculations, reservoir management and saline water disposal. The occurrence of saline formation water in the Palm Valley field has been the subject of considerable debate. There were no occurrences of mobile water early in the development of the field and only after gas production had reduced the reservoir pressure, was saline formation water produced. Initially this was in small quantities but has increased dramatically with time, particularly after the initiation of compression in November 1996. The produced waters range from highly saline (up to 300,000 mg/L TDS), with unusual enrichments in Ca, Ba and Sr, to low salinity fluids that may represent condensate waters. The Sr isotopic compositions of the ...

CERN Document Server

Spatially resolved studies of star forming regions show that the assumption of spherical geometry is not realistic in most cases, with a major complication posed by the gas being ionised by multiple non-centrally located stars or star clusters. We try to isolate the effects of multiple non-centrally located stars on the temperature and ionisation structure of HII regions, via the construction of 3D photoionisation models using the 3D Monte Carlo photoionisation code MOCASSIN. We find that the true temperature fluctuations due to the stellar distribution (as opposed to the large-scale temperature gradients due to other gas properties) are small in all cases and not a significant cause of error in metallicity studies. Strong emission lines from HII regions are often used to study the metallicity of star-forming regions. We compare integrated emission line spectra from our models and quantify any systematic errors caused by ...

Energy Technology Data Exchange (ETDEWEB)

In order to study the two-phase natural circulation and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed. Based on the two-phase flow scaling criteria developed under this program, an adiabatic hot leg U-bend simulation loop using nitrogen gas and water and a Freon 113 boiling and condensation loop were built. The nitrogen-water system has been used to isolate key hydrodynamic phenomena from heat transfer problems, whereas the Freon loop has been used to study the effect of phase changes and fluid properties. Various tests were carried out to establish the basic mechanism of the flow termination and reestablishment as well as to obtain essential information on scale effects of parameters such as the loop frictional resistance, thermal center, U-bend curvature and inlet geometry. In addition to the above experimental study, a preliminary modeling study has been carried out for ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes the development of a computational multiphase fluid dynamics (CMFD) model of the Fischer Tropsch (FT) process in a Slurry Bubble Column Reactor (SBCR). The CMFD model is fundamentally based which allows it to be applied to different industrial processes and reactor geometries. The NPHASE CMFD solver [1] is used as the robust computational platform. Results from the CMFD model include gas distribution, species concentration profiles, and local temperatures within the SBCR. This type of model can provide valuable information for process design, operations and troubleshooting of FT plants. An ensemble-averaged, turbulent, multi-fluid solution algorithm for the multiphase, reacting flow with heat transfer was employed. Mechanistic models applicable to churn turbulent flow have been developed to provide a fundamentally based closure set for the equations. In this four-field model formulation, two of the fields are used to track ...

Energy Technology Data Exchange (ETDEWEB)

To carry out studies on the radon behavior under controlled and stable conditions it was designed and constructed a system that consists of two parts: a container of mineral rich in Uranium and an experimentation chamber with radon united one to the other one by a step valve. The container of uranium mineral approximately contains 800 gr of uranium with a law of 0.28%; the radon gas emanated by the mineral is contained tightly by the container. When the valve opens up the radon gas it spreads to the radon experimental chamber; this contains 3 accesses that allow to install different types of detectors. The versatility of the system is exemplified with two experiments: 1. With the radon experimental chamber and an associated spectroscopic system, the radon and two of its decay products are identified. 2. The design of the system allows to couple the mineral container to other experimental geometries to demonstrate this fact ...

Science.gov (United States)

High performance sorbents for flue gas desulfurization can be synthesized by hydration of coal fly ash, calcium sulfate, and calcium oxide. In general, higher desulfurization activity correlates with higher sorbent surface area. Consequently, a major aim in sorbent synthesis is to maximize the sorbent surface area by optimizing the hydration conditions. This work presents an integrated modeling and optimization approach to sorbent synthesis based on statistical experimental design and two artificial intelligence techniques: neural network and genetic algorithm. In the first step of the approach, the main and interactive effects of three hydration variables on sorbent surface area were evaluated using a full factorial design. The hydration variables of interest to this study were hydration time, amount of coal fly ash, and amount of calcium sulfate and the levels investigated were 4-32 h, 5-15 g, and 0-12 g, respectively. In ...

Energy Technology Data Exchange (ETDEWEB)

Inverted annular flow can be visualized as a liquid jet-like core surrounded by a vapor annulus. While many analytical and experimental studies of heat transfer in this regime have been performed, there is very little understanding of the basic hydrodynamics of the post-CHF flow field. However, a recent experimental study was done that was able to successfully investigate the effects of various steady-state inlet flow parameters on the post-CHF hydrodynamics of the film boiling of a single phase liquid jet. This study was carried out by means of a visual photographic analysis of an idealized single phase core inverted annular flow initial geometry (single phase liquid jet core surrounded by a coaxial annulus of gas). In order to extend this study, a subsequent flow visualization of an idealized two-phase core inverted annular flow geometry (two-phase central jet core, surrounded by a coaxial annulus of ...

Energy Technology Data Exchange (ETDEWEB)

The core bypass flow in a prismatic very high temperature gas-cooled reactor (VHTR) is one of the important design considerations which impacts considerably on the integrity of reactor core internals including operating fuels. The interstitial gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The occurrence of hot spots in the core and lower plenum and hot streaking in the lower plenum (regions of very hot gas flow) will be affected by the bypass flow. In the present study, three-dimensional computational fluid dynamic (CFD) calculations of a typical prismatic VHTR are conducted to understand better the bypass flow phenomenon and establish the evaluation method in the reactor core using ...

Energy Technology Data Exchange (ETDEWEB)

Gene analysis was used to determined the presence, abundance and phylogenetic affiliation of methanogens that exist in gas-hydrate-bearing sediment samples obtained from 23 drill cores from the JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate research well. Rates of methane production were examined using sediment-inoculated enrichments containing {sup 14}C-labeled carbon substrates, carbon dioxide and acetate. Archaeal 16S rDNA was only detected in 6 of the samples, resulting in 8 sequences with relationships to the Miscellaneous Crenarchaeotic Group (7 clones) and the Subsurface Euryarchaeotic Group (1 clone). The single Euryarchaeota sequence did not appear to be related to methanogens. Subsamples from the cores showed variable results upon DNA extraction and amplification. Methanogenic Coenzyme M (CoM) was detected in 13 of the 20 cores, but methanogenic methyl CoM reductase genes were not amplified from the samples when ...

Energy Technology Data Exchange (ETDEWEB)

The deexcitation of quasi-projectiles (QP) released in binary Au on Au collisions as been studied from 60 to 100 MeV/u. Bimodality between two different decay patterns has been observed for intermediate violence collisions. The main experimental result is that the system jumps from one mode to the other on a narrow range of energy deposit and/or impact parameter. The sorting of the events (according to the violence of the collision) has been provided by the perpendicular energy of the light charged particles emitted on the quasi-target side. Such a sorting prevents spurious autocorrelation effects between the sorting variable and the observed mechanism. The two modes of the QP decay correspond on the one side to residue or fission fragments production, and on the other side to the multifragmentation channel. A detailed study has been performed in order to try to establish the origin of the observed bimodality in disentangling dynamical or geometrical effects from ...

DEFF Research Database (Denmark)

Udgivelsesdato: 1995-Nov

Energy Technology Data Exchange (ETDEWEB)

The design of the first structural wall (FSW) in an inertial confinement fusion (ICF) reactor requires some knowledge of the expected wall loading produced by x-ray and neutron deposition; specifically in the High Yield Lithium Injection Fusion Energy (HYLIFE) reactor, wall loading results from two sources -- gas shock and liquid impact. Gas shock is derived from x-ray deposition in the thin layers of exposed blanket material, producing ionized vapor, which will generate gas shock on the FSW. Liquid impact, on the other hand, results from the acceleration of liquid blanket material by two possible forces -- the drag from vapor expansion through the blanket material and the neutron-induced isochoric disassembly process. Both impacts, however, are coupled by the interaction of hot gas expanding through the liquid blanket. This paper discusses scaling methods for estimating pressure and impulse on the ...

Science.gov (United States)

Not Available

CERN Document Server

Design and Analysis of Vaccine Studies

Energy Technology Data Exchange (ETDEWEB)

A kinetic study of the degradation by ozone of eight phenolic acids present in wastewaters from olive oil mills has been performed by using a competition kinetic method. The selected phenolic acids are: caffeic, p-coumaric, syringic, vanillic, 3,4,5-trimethoxybenzoic, veratric, p-hydroxy-benzoic, and protocatechuic. The influence of the operating variables (temperature, pH, and ozone partial pressure in the gas stream) is established, and the stoichiometric ratios for the individual direct reactions between ozone and each acid are determined. Once the reaction rate constants are evaluated, they are correlated as a function of temperature and pH into kinetic expressions which are provided for every phenolic acid. The global process occurs in the fast and pseudo-first-order kinetic regime of absorption, a condition required by the competition model to be used.

Energy Technology Data Exchange (ETDEWEB)

Excitation of low temperature helium or helium/water plasma and subsequent exposure to air of polyacrylonitrile (PAN) ultrafiltration membranes was used to hydrophilize the surface of these materials. We analyzed the effectiveness of this approach as a function of plasma operating variables including gas phase composition, plasma power, treatment time and system pressure. Following the changes in physical and chemical composition of the PAN surface resulting from these modifications was a major aspect of this work. Techniques such as the captive bubble contact angle method, ellipsometry, ESCA, and FTIR-ATR were all used. In addition, the formation and life-time of peroxides during these processes were determined. At low powers (<25W) and short treatment periods ({<=}30 sec), the main chemical conversion of PAN surfaces was simultaneous hydrophilization and stabilization via PAN cyclization. Relatively small water permeability changes were ...

International Nuclear Information System (INIS)

Throughout the last decades, plasma technology has been established in a series of surface treatment applications, e.g. for semiconductor processing or optical coatings. The majority of plasma assisted technologies is based on low pressure processes. In recent years, however, non-thermal atmospheric pressure discharges have attracted considerable interest because of their simplified technical devices for industrial applications as compared to low pressure processes which require vacuum equipment. Hence, batch processing can be avoided, thus facilitating the implementation of plasma process steps into production lines. Investment costs are cut down significantly. The use of atmospheric pressure plasmas for technical applications dates back to the ozone production with dielectric barrier discharges (DBD) by Siemens in 1857. Lately, the application of atmospheric pressure plasmas for surface treatment has been reported, e.g. for the treatment of foils to improve printability, for surface ...

Energy Technology Data Exchange (ETDEWEB)

The particulate matter of a light-duty diesel engine was characterized in its morphology, sizes, internal microstructures, and fractal geometry. A thermophoretic sampling system was employed to collect particulates directly from the exhaust manifold of a 1.7-liter turbocharged common-rail direct-injection diesel engine. The particulate samples collected at various engine-operating conditions were then analyzed by using a high-resolution transmission electron microscope (TEM) and an image processing/data acquisition system. Results showed that mean primary particle diameters (dp), and radii of gyration (Rg), ranged from 19.4 nm to 32.5 nm and 77.4 nm to 134.1 nm, respectively, through the entire engine-operating conditions of 675 rpm (idling) to 4000 rpm and 0% to 100% loads. It was also revealed that the other important parameters sensitive to the particulate formation, such as exhaust-gas recirculation (EGR) rate, equivalence ratio, and ...

Energy Technology Data Exchange (ETDEWEB)

This study identifies potential applications and design requirements for ceramic materials (CMs) and ceramic composite materials (CCMs) in the NGNP hightemperature gas-cooled reactor (HTGR) primary circuit. Components anticipated for fabrication from non-graphite CMs and CCMs are identified along with recommended normal and off-normal operating conditions. The evaluation defines required dimensions and material properties of the candidate materials for normal operating conditions (NOC), anticipated transients, abnormal events, and design basis events. The report also identifies additional activities required for codifying the selected materials. The activities include ASTM Standard and ASME Code development and other work to support NRC licensing of the plant. Evaluation of the NGNP baseline design indicates components requiring either CMs or CCMs depend upon the reactor operating temperatures. For a reactor outlet temperature of 900 oC, four of the five evaluated ...

International Nuclear Information System (INIS)

The Phebus FP project in an international reactor safety project. Its main objective is to study the release, transport and retention of fission products in a severe accident of a Light Water Reactor (LWR). The FPT4 test was performed with a fuel debris bed geometry, to look at late phase core degradation and the releases of low volatile fission products and actinides. Post Test Analyses results indicate that releases of noble gases (Xe, Kr) and high-volatile fission products (Cs, I) were nearly complete and comparable to those obtained during Phebus tests performed with a fuel bundle geometry (FPT1, FPT2). Volatile fission products such as Mo, Te, Rb, Sb were released significantly as in previous tests. Ba integral release was greater than that observed during FPT1. Release of Ru was comparable to that observed during FPT1 and FPT2. As in other Phebus tests, the Ru distribution suggests Ru volatilization followed by fast redeposition in the ...

Energy Technology Data Exchange (ETDEWEB)

During the past few years, the dual role that ozone plays in climate change has been becoming increasingly obvious. First, continuous thinning of the ozone layer has been evident, even in the high and middle latitudes in the northern hemisphere. Secondly, ozone is also a greenhouse gas, affecting radiative transfer. Increases in tropospheric ozone have a positive forcing, whereas decreases in stratospheric ozone cause a negative forcing. During the last six years, measurements on total ozone and the vertical distribution of ozone have been performed at the Sodankylae Observatory. At Jokioinen Observatory, measurements on total ozone have been performed since 1990 and measurements on the vertical distribution of ozone since 1993. The overall project has focused on extending the national data series on total ozone and the vertical distribution of ozone. At the same time, the study has contributed to the study of interannual variability of the ...

British Library Electronic Table of Contents (United Kingdom)

Headspace solid-phase microextraction (HS-SPME) coupled to comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) was applied for equilibrium headspace analysis of Malaysian soursop (Annona muricata) volatile flavor compounds. A two-level fractional factorial design (25-1) was used to determine the effect of SPME variables, namely, SPME fibers, adsorption temperature, extraction time, amount of salt, sample amount and sample concentration on the extraction efficiency of volatile flavor compounds. A total of 37 volatile compounds were identified, comprising 21 esters, 6 alcohols, 3 terpenes, 2 acids, 2 ketones, 2 aldehydes and an aromatic with different hydrophobicities (log P) ranging between -0.14 and 4.83. Extraction using 10g of diluted (5% w/w) ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes the design and feasibility tests of a 570 mm bore 4 stroke low pressure (L.P.) dual fuel engine rated at 20.9 bar BMEP meant for the propulsion of LNG carriers. The basic design features which are to be in accordance with classification societies safety rules are described: individual electro hydraulic valves located in the air manifold ducts, pilot injection, monitoring system etc. The engine capability to burn variable liquid/gas fuel proportions have been investigated with diesel oil and heavy fuel and possible running zones are defined. This ensures the possibility of the engine to cope with the different boil off gas quantity emanating from the ship`s tank during her loaded - and ballast - journeys. With the very lean setting of this engine, no adverse influence of the high ash lube-oil additives were found during the tests. Further tests are necessary to confirm that possible more significant ...

Energy Technology Data Exchange (ETDEWEB)

Three dimensional computational fluid dynamic (CFD) calculations of a typical prismatic very high temperature gas-cooled reactor (VHTR) were conducted to investigate the influence of gap geometry on flow and temperature distributions in the reactor core using commercial CFD code FLUENT. Parametric calculations changing the gap width in a whole core length model of fuel and reflector columns were performed. The simulations show the effects of core by-pass flows in the heated core region by comparing results for several gap widths including zero gap width. The calculation results underline the importance of considering inter-column gap width for the evaluation of maximum fuel temperatures and temperature gradients in fuel blocks. In addition, it is shown that temperatures of core outlet flow from gaps and channels are strongly affected by the gap width of by-pass flow in the reactor core.

Science.gov (United States)

Measurements of PEM fuel cell device performance were made with different gas inlet temperatures and relative humidity using a newly-designed test fixture. Significant improvement in device performance was observed when the fuel inlet temperature was increased above the operating temperature of the cell. These measurements were then correlated to a model to describe energy and mass transport processes. Proton exchange membrane (PEM), fuel cells--the focus of this study--use an ion conducting polymer, especially polyperfluorosulfonic acid materials. These polymer materials, when imbibed with water, exhibit solution-like properties, but because the anions are chemically bound to the polymeric structure, the electrolyte is contained. Importantly, product water removal is simplified, as electrolyte dilution is not a concern. However, the proton transport rate is a function of the polymer geometry, which is set, in part, by the polymer water ...

Energy Technology Data Exchange (ETDEWEB)

A copyrighted computational fluid dynamics computer code, ICOMFLO, has been developed for the simulation of multiphase reacting flows. The code solves conservation equations for gaseous species and droplets (or solid particles) of various sizes. General conservation laws, expressed by elliptic type partial differential equations, are used in conjunction with rate equations governing the mass, momentum, enthalpy, species, turbulent kinetic energy, and turbulent dissipation. Associated phenomenological submodels of the code include integral combustion, two parameter turbulence, particle evaporation, and interfacial submodels. A newly developed integral combustion submodel replacing an Arrhenius type differential reaction submodel has been implemented to improve numerical convergence and enhance numerical stability. A two parameter turbulence submodel is modified for both gas and solid phases. An evaporation submodel treats not only droplet evaporation but size ...

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This document is a user`s manual for the Rn3D finite element code. Rn3D was developed to simulate gas flow and radon transport in variably saturated, nonisothermal porous media. The Rn3D model is applicable to a wide range of problems involving radon transport in soil because it can simulate either steady-state or transient flow and transport in one-, two- or three-dimensions (including radially symmetric two-dimensional problems). The porous materials may be heterogeneous and anisotropic. This manual describes all pertinent mathematics related to the governing, boundary, and constitutive equations of the model, as well as the development of the finite element equations used in the code. Instructions are given for constructing Rn3D input files and executing the code, as well as a description of all output files generated by the code. Five verification problems are given that test various aspects of code operation, complete with example input ...

Energy Technology Data Exchange (ETDEWEB)

The thesis relates to an investigation done on greenhouse gases in coniferous forest soils. The production of nitrous oxide (N{sub 2}O) and carbon dioxide (CO{sub 2}), and the consumption of methane (CH{sub 4}) in a temperate forest soil were studied by a rapid and sensitive gas chromatographic (GC) method for analysing all three greenhouse gases at or below ambient levels. Gas fluxes were measured in soil incubation and lysimeter experiments. 15 soil samples were taken at random within a 100 m{sup 2} area in a Norway spruce forest stand (Picea abies). The fluxes of N{sub 2}O, CH{sub 4} and CO{sub 2} were measured under standardized laboratory incubation conditions to investigate spatial variability in relation to other factors such as nitrogen (N) mineralization rate, nitrification rate, organic carbon (OC), total N and pH. The effects of temperature, soil moisture content, and ammonium addition were also studied in an ...

International Nuclear Information System (INIS)

The assessment of greenhouse gas impacts in the US shows that against a baseline gasoline vehicle, the impact of including the full fuel cycle generally reduces the relative advantages of alternative transportation fuels. While a switch to diesel is estimated to save 30% as compared to gasoline, the savings from natural gas/LPG are (around 20%), for ethanol from corn (8%) and for battery electricity vehicles using power from coal (6%) are much smaller. This is largely due to the use of LCA rather than end-use comparisons. However, the results also show that there would be large savings from the use of ethanol from fuel cells using methanol (39%) or natural gas (50%), while ethanol from wood in a conventional engine appears to have the greatest savings (63%). In external costs of motor vehicle use, analysis results were presented for both air pollution and energy security impacts (including SPR, military expenditures, ...

Energy Technology Data Exchange (ETDEWEB)

Computational transport models are described with applications in three problem areas related to unsaturated zone moisture movement beneath Area G. These studies may be used to support the ongoing maintenance of the site Performance Assessment. The three areas include: a 1-D transient analysis with average tuff hydraulic properties in the near surface region with computed results compared to field data; the influence on near surface transient moisture percolation due to realistic distributions in hydraulic properties derived statistically from the observed variance in the field data; and the west to east moisture flow in a 2-D steady geometry approximation of the Pajarito Plateau. Results indicate that a simple transient model for transport of moisture volume fraction fits field data well compared to a moisture pulse observed in the active disposal unit, pit 37. Using realistic infiltration boundary conditions for summer showers and for spring snow melt conditions, ...

Energy Technology Data Exchange (ETDEWEB)

The bobbin probe technique is basically one of the important ECT methods for the steam generator tube integrity assessment that is practiced during each plant outage. The bobbin probe also is the essential component which consists of the whole ECT examination system, and provides a decisive data for the evaluation of tube integrity in compliance with acceptance criteria described in specific procedures. The selection of probe is especially important because the quality of acquired ECT data is determined by the probe design characteristics, such as geometry and operation frequency, and has an important effect on examination results. The Electric Power Research Institute (EPRI) has recently defined the procedures for the qualification of eddy current hardware and technique. These procedures provide two basic methods for qualification. Flawed tube removed from operation, or artificial flaw is required for the original qualification of technique combined with related ...

Energy Technology Data Exchange (ETDEWEB)

In large samples, the {gamma}-ray count rate of a prompt gamma neutron activation analysis system is a multi-variable function of the elemental dry composition, density, water content and thickness of the material. The experimental calibration curves require tremendous laboratory work, using a great number of standards with well-known compositions. Although a Monte Carlo simulation study does not avoid the experimental calibration work, it reduces the number of experimental calibration standards. This paper is part of a feasibility study for a PGNAA system for on-line continuous characterisation of cement raw material conveyed on a belt (Oliveira, C., Salgado, J. and Carvalho, F. G. (1997) Optimisation of PGNAA instrument design for cement raw materials using the MCNP code. J. Radioanal. Nucl. Chem. 216(2), 191-198; Oliveira, C., Salgado, J., Goncalves, I. F., Carvalho, F. G. and Leitao, F. (1997a) A Monte Carlo study of the influence of ...

Energy Technology Data Exchange (ETDEWEB)

For a simplicial manifold we construct the differential geometry structure and use it to investigate linear connections, metric and gravity. We discuss and compare three main approaches and calculate the resulting gravity action functionals. (author)

CERN Document Server

An introduction to recent developments in several active topics at the interface between algebra, geometry, topology and quantum field theory

Science.gov (United States)

An advanced experimental technique has been developed to simulate two-phase flow behavior in a light water reactor (LWR). The technique applies three kinds of methods; (1) use of sulfur-hexafluoride (SF6) gas and ethanol (C2H5OH) liquid at atmospheric temperature and a pressure less than 1.0MPa, where the fluid properties are similar to steam-water ones in the LWR, (2) generation of bubble with a sintering tube, which simulates bubble generation on heated surface in the LWR, (3) measurement of detailed bubble distribution data with a bi-optical probe (BOP), (4) and measurement of liquid velocities with the tracer liquid. This experimental technique provides easy visualization of flows by using a large scale experimental apparatus, which gives three-dimensional flows, and measurement of detailed spatial distributions of two-phase flow. With this technique, we have carried out experiments simulating two-phase flow behavior in a single-channel ...

Energy Technology Data Exchange (ETDEWEB)

The electric power industry can use the carbon dioxide absorption process to capture carbon from high-volume flue gas. However, the current cost of the process is too high due to the approximation method used in process design. The absorption column is typically designed with parameters that are assumed to be constant over the whole length of the column, resulting in an oversized unit. This approximation method is no longer valid given new environmental and economic concerns. In order to develop an accurate column design for high-efficiency carbon dioxide (CO{sub 2}) capture, it is necessary to understand the phenomena taking place in the system. A mechanistic model is presented for a robust absorber design that takes into account mass-transfer and hydrodynamic behaviour within the CO{sub 2} absorption columns. The capture performance of a packed column under a wide range of design and operating conditions was determined using a model based on the kinetics and ...

Science.gov (United States)

The effect of liquefied natural gas on pollutant emissions was evaluated experimentally with used and new appliances in the laboratory and with appliances installed in residences, targeting information gaps from previous studies. Burner selection targeted available technologies that are projected to comprise the majority of installed appliances over the next decade. Experiments were conducted on 13 cooktop sets, 12 ovens, 5 broiler burners, 5 storage water heaters, 4 forced air furnaces, 1 wall furnace, and 6 tankless water heaters. Air-free concentrations and fuel-based emission factors were determined for carbon monoxide, nitrogen oxides, nitrogen dioxide, and the number of (predominantly ultrafine) particles over complete burns?including transient effects (device warm-up and intermittent firing of burners) following ignition--and during more stable end-of-burn conditions. Formaldehyde was measured over multi-burn cycles. The baseline fuel was Northern California ...

Energy Technology Data Exchange (ETDEWEB)

Coupled modeling of subsurface multiphase fluid and heat flow, solute transport and chemical reactions can be used for the assessment of acid mine drainage remediation, mineral deposition, waste disposal sites, hydrothermal convection, contaminant transport, and groundwater quality. Here they present a numerical simulation model, TOUGHREACT, which considers non-isothermal multi-component chemical transport in both liquid and gas phases. A wide range of subsurface thermo-physical-chemical processes is considered. The model can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The model can accommodate any number of chemical species present in liquid, gas and solid phases. A variety of equilibrium chemical reactions is considered, such as aqueous complexation, gas dissolution/exsolution, cation exchange, and surface complexation. Mineral ...

Energy Technology Data Exchange (ETDEWEB)

Sprayforming offers the possibility to produce a variety of preforms in a single step directly from the melt. Numerous processing parameters ensure high flexibility but require detailed knowledge concerning the microstructure of sprayformed material depending on chemical composition and processing parameters. Within the current study fundamental investigations using unalloyed and low alloy steel grades (C15, C105, 100Cr6) for sprayforming of plates and billets have been performed concerning the influence of chromium and carbon content and selected processing parameters. Sprayformed preforms revealed austenite grain sizes up to 500 {mu}m depending on the development of porosity. Different types of porosity have been detected which can be associated with incomplete densification due to high cooling rates, solidification shrinkage and entrapped nitrogen. Atomisation gas pressure and carbon content are parameters of primary importance. (Abstract Copyright [2003], Wiley ...

CERN Document Server

We present first worldline numerical results for the nontrivial interplay between geometry and temperature dependencies of the Casimir effect. We show that the temperature dependence of the Casimir force can be significantly larger for open geometries (e.g., perpendicular plates) than for closed geometries (e.g., parallel plates). For surface separations in the experimentally relevant range, the thermal correction for the perpendicular-plates configuration exhibits a stronger parameter dependence and exceeds that for parallel plates by more than an order of magnitude at room temperature. This effect can be attributed to the fact that the fluctuation spectrum for closed geometries is gapped, inhibiting the thermal excitation of modes at low temperatures. By contrast, open geometries support a thermal excitation of the low-lying modes in the gapless spectrum already at low ...

International Nuclear Information System (INIS)

The formation and evolution of the circumstellar disk in unmagnetized molecular clouds is investigated using three-dimensional hydrodynamic simulations from the prestellar core until the end of the main accretion phase. In collapsing cloud cores, the first (adiabatic) core with a size of #approx#>3 AU forms prior to the formation of the protostar. At its formation, the first core has a thick disk-like structure and is mainly supported by the thermal pressure. After the protostar formation, it decreases the thickness gradually and becomes supported by the centrifugal force. We found that the first core is a precursor of the circumstellar disk with a size of >3 AU. This means that unmagnetized protoplanetary disk smaller than <3 AU does not exist. Reflecting the thermodynamics of the collapsing gas, at the protostar formation epoch, the first core (or the circumstellar disk) has a mass of #approx#0.005-0.1 M_s_u_n, while the protostar has a mass of ...

International Nuclear Information System (INIS)

This work presents a comparative study of low-alloy steel nitriding for different possible techniques. Active screen plasma nitriding (ASPN) is a successful surface modification method that has many advantages over the conventional DC plasma nitriding (CPN). The corrosion behavior of 30CrNiMo8 low-alloy steel has been examined using anodic polarization tests in 3.5% NaCl solution under varying conditions of ASPN and CPN processes. The process variables included active screen setup parameters, treatment temperature (550 and 580 deg. C), gas mixture (25/75 and 75/25 of N_2/H_2) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the compound layer was studied by X-ray diffraction (XRD), microhardness tests, optical microscopy and scanning electron microscopy (SEM). It was observed that ASPN treated samples surface enhanced corrosion resistance while the temperature and/or hole size of screen setup ...

International Nuclear Information System (INIS)

The reactive evaporation process was successfully used to deposit films of the A-15 Nb_3Ge phase. This is the first report, to the best of our knowledge, illustrating the use of such processes for the deposition of A-15 compounds. In this process, niobium vapors from an electron-beam-heated evaporation source react with germane gas introduced into the vacuum chamber at low partial pressures (approximately 10"-"4 Torr) to produce Nb_3Ge deposits. The process variables studied were the deposition temperature, the niobium-to-germanium impingement ratio on the substrate and the plasma-enhanced deposition, in this case the activated reactive evaporation process. At low deposition temperatures (below 450"0C) the deposit is amorphous (or microcrystalline) and can be crystallized to the Nb_3Ge phase by heat treatment, e.g. at 850"0C for 1 h in vacuum. The ratio of niobium to germanium in the deposit can be varied by changing the process parameters. The ...

Energy Technology Data Exchange (ETDEWEB)

A major problem in the maintenance and rehabilitation of pipelines is the removal of the original coating system, particularly in cases where the coating contains sticky components or adhesives. It has been found that such coatings can be removed by use of a cleaning machine with a plurality of counter-rotating carbide-tipped tools mounted to an oscillating head embracing the pipe, and which is operable at the same time to travel along the length of the pipe. Such a machine can be designed to effect a positive, gentle milling operation on the pipe surface to remove the coating efficiently and at relatively low power consumption. A particular advantage of the pipe cleaning machine of the invention is that its design and manner of operation allows it to be used in the field to clean an uncovered section of pipeline, for example a natural gas pipeline, without the requirement of removing the pipeline section from the ditch in which it is seated. The machine of the ...

CERN Document Server

For purposes of designing targeted cataclysmic variable (CV) detection surveys and interpreting results of other projects with many CV detections such as the ChaMPlane Survey, we have created a model of the CV distribution in the Galaxy. It is modeled as a warped, flared exponential disk with a gaussian vertical distribution. Extinction is based on a detailed Galactic dust and gas model. A luminosity function for CVs is also incorporated, based on a smoothed version of published data. We calculate predicted field detection rates as a function of the limiting magnitude expected for the detecting system (i.e. WIYN/Hydra or NOAO 4m/Mosaic). Monte-Carlo techniques are used to assess statistical fluctuations in these rates. We have created maps of the expected CV distribution for the full non-bulge Galactic plane (20

Energy Technology Data Exchange (ETDEWEB)

This technology development plan is designed to provide a clear understanding of the research and development direction necessary for the qualification of nuclear grade graphite for use within the Next Generation Nuclear Plant (NGNP) reactor. The NGNP will be a helium gas cooled Very High Temperature Reactor (VHTR) with a large graphite core. Graphite physically contains the fuel and comprises the majority of the core volume. Considerable effort will be required to ensure that the graphite performance is not compromised during operation. Based upon the perceived requirements the major data needs are outlined and justified from the perspective of reactor design, reatcor performance, or the reactor safety case. The path forward for technology development can then be easily determined for each data need. How the data will be obtained and the inter-relationships between the experimental and modeling activities will define the technology development for graphite ...

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The relationship between coal properties and liquefaction or gasification characteristics was analyzed by using the analysis and test results and liquefaction characteristics in the coal data base. On liquefaction reaction, the close relation between an oil yield and coal constituent composition or a coal rank is well-known. Various multivariable regression analyses were conducted by using 6 factors as variables such as calorific value, volatile component, O/C and H/C atomic ratios, exinite+vitrinite content and vitrinite reflectance, and liquefaction characteristics as variate. On liquefaction characteristics, the oil yield of dehydrated and deashed coals, asphaltene yield, hydrogen consumption, produced water and gas quantities, and oil+asphaltene yield were predicted. The theoretical gasification efficiency of each specimen was calculated to evaluate the liquefaction reaction obtained. As a result, the oil yield increased with H/C atomic ...

Energy Technology Data Exchange (ETDEWEB)

The atmosphere and the biosphere are inherently coupled to one another. Atmospheric surface state variables such as temperature, winds, water vapor, precipitation, and radiation control biophysical, biogeochemical, and ecological processes at the surface and subsurface. At the same time, surface fluxes of momentum, moisture, heat, and trace gases act as time-dependent boundary conditions providing feedback on atmospheric processes. To understand such phenomena, a coupled set of interactive models is required. Costs are still prohibitive for computing surface/subsurface fluxes directly for medium-resolution atmospheric general circulation models (AGCMs), but a technique has been developed for testing large-scale homogeneity and accessing surface parameterizations and models to reduce this computational cost and maintain accuracy. This modeling system potentially bridges the observed spatial and temporal ranges yet allows the incorporation of necessary details about ...

KoreaScience (Korea)

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KoreaScience (Korea)

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International Nuclear Information System (INIS)

... biological variability body distribution kidneys labelled compounds lead 203

Energy Technology Data Exchange (ETDEWEB)

In order to practice a design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, the immediate concern is improvement in its predictive capability of CHF due in particular to the film dryout (boiling transition phenomena: BT) on the fuel rod surface. Constitutive equations in the subchannel analysis formulation are responsible for the quality of calculated results. The constitutive equations are a result of integration of the local and instantaneous description of two-phase flows over the subchannel control volume. In general, they are expressed in terms of subchannel-control-volume- as well as area-averaged two-phase flow state variables. In principle the information on local and instantaneous physical phenomena taking place inside subchannels must be counted for in the algebraic form of the equations on the basis of a more mechanistic modeling approach. They should include also influences of the ...

International Nuclear Information System (INIS)

In order to practice a design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, the immediate concern is improvement in its predictive capability of CHF due in particular to the film dryout (boiling transition phenomena: BT) on the fuel rod surface. Constitutive equations in the subchannel analysis formulation are responsible for the quality of calculated results. The constitutive equations are a result of integration of the local and instantaneous description of two-phase flows over the subchannel control volume. In general, they are expressed in terms of subchannel-control-volume- as well as area-averaged two-phase flow state variables. In principle the information on local and instantaneous physical phenomena taking place inside subchannels must be counted for in the algebraic form of the equations on the basis of a more mechanistic modeling approach. They should include also influences of the ...

International Nuclear Information System (INIS)

Purpose: Various published reports involving intensity-modulated radiotherapy (IMRT) plans developed using automated optimization (inverse planning) have demonstrated highly conformal plans. These reported conformal IMRT plans involve significant target dose inhomogeneity, including both overdosage and underdosage within the target volume. In this study, we demonstrate the development of optimized beamlet IMRT plans that satisfy rigorous dose homogeneity requirements for all target volumes (e.g., #+-#5%), while also sparing the parotids and other normal structures. Methods and Materials: The treatment plans of 15 patients with oropharyngeal cancer who were previously treated with forward-planned multisegmental IMRT were planned again using an automated optimization system developed in-house. The optimization system allows for variable sized beamlets computed using a three-dimensional convolution/superposition dose calculation and flexible cost functions derived ...

Energy Technology Data Exchange (ETDEWEB)

The theoretical and experimental investigation of the mechanism of SO2 and H2S removal by CaCO3 -based sorbents (limestones and dolomites) in pressurized uidized-bed coal combustors (PFBC) and high pressure gasiers, respectively, is the main objective of this study. It is planned to carry out reactivity evolution experiments under simulated high pressure conditions or in high pressure thermogravimetric and, if needed, uidized- bed reactor (high pressure) arrangements. The pore structure of fresh, heat-treated, and half-calcined solids (dolomites) will be analyzed using a variety of methods. Our work will focus on limestones and dolomites whose reaction with SO2 or H2S under atmospheric conditions has been studied by us or other research groups in past studies. Several theoret- ical tools will be employed to analyze the obtained experimental data including a variable diusivity shrinking-core model and models for diusion, reaction, and structure evolution in ...

Energy Technology Data Exchange (ETDEWEB)

The invention relates to a method for purifying a gas mixture containing at least one undesirable gas compound utilizing certain sulfonamide or sulfamide solvents.

Energy Technology Data Exchange (ETDEWEB)

An optimization of fuel bundle geometry using the subchannel code ASSERT is performed in support of Candu fuel design to enhance the thermohydraulics performance. The new bundle design is based on a reference CANFLEX bundle with changes to the centre and inner-ring element diameters and pitch-circle diameters (PCDs) of various element rings. Different methods of varying the PCDs for reaching the optimized geometry are considered in an attempt to minimize the optimization effort. The optimized geometry in the present analysis is the one that maximizes the dryout power and that has simultaneous CHF (critical heat flux) initiation involving more than one subchannel rings. (authors)

Energy Technology Data Exchange (ETDEWEB)

Average emittance data for ion beams extracted from cesium-sputter negative ion sources equipped with spherical, ellipsoidal, and cylindrical geometry cesium-surface ionizers are presented. The attributes of the respective source geometries are described in terms of their cesium ion optical properties. The results of recent measurement of the emittances of momentum-analyzed beams extracted from the ellipsoidal geometry source are also presented. These measurements indicate the presence of a species-dependent effect. The effect is believed to be attributable to differences in the energy spreads of the respective negative ion beams introduced by the sputter generation process. 11 refs., 8 figs.

International Nuclear Information System (INIS)

Gyrokinetic particle simulation of edge pedestal formation and plasma rotation dynamics will be presented, and compared with experimental observations. Realistic tokamak edge geometry is used which include separatrix/X-point and material wall from EFIT g-eqdsk data. In order to handle adequately the spatially inhomogeneous electric potential in the scrape-off region, the full-f electron technique is used, in addition to the full-f ions. Monte Carlo neutral particles with wall recycling coefficient will be included self-consistently with the plasma kinetics. Ion-ion Coulomb collisions will be particle, momentum and energy conserving. Energy source for the pedestal and scrape-off plasmas is the heat flow from the core plasma, and the particle source is the ionization of the neutral atoms which are either wall recycled and/or gas puffed. The simulation will be self-consistent with the first principles nonlinear neoclassical and (electrostatic so ...

Energy Technology Data Exchange (ETDEWEB)

As the jump from 2D to 3D, seismic exploration lives a new revolution with the use of converted PS waves. Indeed PS converted waves are proving their potential as a tool for imaging through gas; lithology discrimination; structural confirmation; and more. Nevertheless, processing converted shear data and in particular determining accurate P and S velocity models for depth imaging of these data is still a challenging problem, especially when the subsurface is anisotropic. To solve this velocity model determination problem we propose to use reflection travel time tomography. In a first step, we derive a new approximation of the exact phase velocity equation of the SV wave in anisotropic (TI) media. This new approximation is valid for non-weak anisotropy and is mathematically simpler to handle than the exact equation. Then, starting from an isotropic reflection tomography tool developed at Lt-'P, we extend the isotropic bending ray tracing method to the ...

International Nuclear Information System (INIS)

Metal waste generated from domestic nuclear operation for defense and commercial application has led to a growing stockpile of radioactively contaminated scrap metal, much of which is stainless steel. A significant fraction of this material cannot be efficiently surface decontaminated. The burial of this material would be wasteful and expensive, since long term monitoring would be necessary in order to minimize environmental risk. Much of this waste consists of bulky equipment. In many case, this equipment contains valuable material that may be recycled. The piece of equipment considered frequently also has complex geometries, making extremely difficult, time-consuming and expensive to determine the exact location and level of radioactivity on the internal surfaces. After melting, however, the radioactivity may be precisely determined from samples of each ingot. Moreover, an ingot may be released for restricted or unrestricted reuse, or stored for decay to ...

Energy Technology Data Exchange (ETDEWEB)

The object of this work is to develop and optimize a new type of light-emitting diode (LED) with a wire-shaped, cylindrical geometry.

Science.gov (United States)

Geometra'. Scrape Geom- ett_,. Used By: Theoretical. FEM Weight. Apply Linear Delta ...... that the FEM is geometri- cally linear, the differences between ...

Energy Technology Data Exchange (ETDEWEB)

Many solutions of General Relativity appear to allow the possibility of time travel. This was initially a fascinating discovery, but geometries of this type violate causality, a basic physical law which is believed to be fundamental. Although string theory is a proposed fundamental theory of quantum gravity, geometries with closed timelike curves have resurfaced as solutions to its low energy equations of motion. In this paper, we will study the class of solutions to low energy effective supergravity theories related to the BMPV black hole and the rotating wave-D1-D5-brane system. Time travel appears to be possible in these geometries. We will attempt to build the causality violating regions and propose that stringy effects prohibit their construction. The proposed chronology protection agent for these geometries mirrors a mechanism string theory employs to resolve a class of naked singularities. ...

Energy Technology Data Exchange (ETDEWEB)

The primary goal of this project is to increase the availability and ease of access to critical data on the Mesaverde and Dakota tight gas reservoirs of the San Juan Basin. Secondary goals include tuning well log interpretations through integration of core, water chemistry and production analysis data to help identify bypassed pay zones; increased knowledge of permeability ratios and how they affect well drainage and thus infill drilling plans; improved time-depth correlations through regional mapping of sonic logs; and improved understanding of the variability of formation waters within the basin through spatial analysis of water chemistry data. The project will collect, integrate, and analyze a variety of petrophysical and well data concerning the Mesaverde and Dakota reservoirs of the San Juan Basin, with particular emphasis on data available in the areas defined as tight gas areas for purpose of FERC. A relational, ...

Energy Technology Data Exchange (ETDEWEB)

Smoke management in buildings during fire events often uses mechanical ventilation systems to maintain smoke layer elevation above a safe evacuation path. Design of these systems requires accurate correlations for the smoke production rate of the buoyant fire plume. One design issue is the smoke production rate of fire plumes which spill out from a fire compartment, under a balcony and up through an atrium or other large volume. Current engineering correlations for these balcony spill plumes are based on a combination of one-tenth scale test data and theoretical analysis. Questions have arisen over the suitability of these correlations for real-scale designs. A combined program of full-scale experimentation and CFD modeling is being conducted to analyze the accuracy of these correlations. A full-scale experimental facility was constructed with a 5 m by 5 m by 15 m fire compartment connected to a four-story atrium. Propane fires in the compartment produce balcony spill plumes which form ...

UK PubMed Central (United Kingdom)

A common property of aging in all animals is that chronologically and genetically identical individuals age at different rates. To unveil mechanisms that influence aging variability, we identified markers...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundDue to the increased accuracy of Copy Number Variable region (CNV) break point mapping, it is now possible to say with a reasonable degree of confidence whether a gene...Full Text Available

UK PubMed Central (United Kingdom)

Background/AimsTo explore different definitions of intra-individual variability (IIV) to summarize performance on commonly utilized cognitive tests (Mini Mental State Exam; Clock...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundVariable platelet response to clopidogrel has been widely observed. Studies have shown that the mean aggregation response to clopidogrel can be changed...Full Text Available

UK PubMed Central (United Kingdom)

A common approach used to fuse simultaneously recorded EEG and fMRI is to correlate trial-by-trial variability in the EEG, or variability of components derived therefrom, with the blood oxygenation...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Abstract not provided

International Nuclear Information System (INIS)

A theory of the asymptotic functions for the case of many variables is presented. It is shown that the class F(R"N) of these generalized functions is closed in respect to the linear algebraic and analytic operations, multiplication as well as a set of linear and polynomial changes of the variables. The existence in F(R"N) of analogues (consistent with the linear operations) of the Schwartz distributions with point support is proved. In terms of these analogues, some formulae for singular products and changes of variables of the Dirac #delta#-function and its derivatives #delta#"("i")(x), x is an element of R"N, are given. (author). 14 refs.

CERN Document Server

Radiation protection and the management of radioactive waste in the oil and gas industry

Wastenet

condenser, gas refiner, oil (gas) storage tank and dual fuel engine

Energy Technology Data Exchange (ETDEWEB)

Success in improving hydropower project efficiency has opened more global markets for variable-speed generator technology. Manufacturers continue to test the markets as the technology evolves. The potential of variable-speed application becomes evident considering that more than 150 pumped storage plants, with a combined capacity exceeding 100,000 MW, are in operation globally.

CERN Document Server

In this paper, we derive the moderate deviation principle for stationary sequences of bounded random variables with values in a Hilbert space. The conditions obtained are expressed in terms of martingale-type conditions. The main tools are martingale approximations and a new Hoeffding inequality for non adpated sequences of Hilbert-valued random variables. Applications to Cramer-Von Mises statistics, functions of linear processes and stable Markov chains are given.

International Nuclear Information System (INIS)

In recent years there has been a renewed interest in the treatment of quantum mechanics in terms of joint distribution functions, i.e. functions of momentum and position coordinates p and q. The author considers j.d.f. in the sense of classical probability theory of a stochastic variable. The j.d.f. is then interpreted as the probability that the variables p and q have certain values, the variables being considered as a property possessed by the object system. This formalism is used to provide a unified description of bradyons and tachyons. (Auth.).

Science.gov (United States)

Respiration and related physiologic variables in different tissues of Barytelphusa guerini and the respiration of this freshwater crab as a whole are closely synchronized in phase and in frequency along the circadian scale, in the face of large differences in circadian amplitude. A very close timing of most of the 36 variables examined in 2 separate circadian profiles and a modulation of some of these variables in added profiles as a function of lunar stage are clearly demonstrable, statistically significant and illustrative of time relations at 2 interacting frequencies. PMID:6745009

Science.gov (United States)

Two-wave mixing in sillenite crystals such as bismuth silicon oxide (Bi12SiO20) and bismuth titanium oxide (Bi12TiO20) of (001)- and (221)-cuts for counterpropagating geometry was studied within the frame of slowly varying amplitude approximation. Electrooptic, photoelastic, piezoelectric, self-diffraction effects and optical activity were taken into account.

International Nuclear Information System (INIS)

Two sets of experiments have been performed in sodium with two seven pin electrically heated bundles: the first with a nominal arrangement, the second with one dummy pin enlarged 20% in diameter in peripheral position. In this paper a rapid review of experimental results and theoretical works, related to the temperature distribution in these geometries, is presented together with a short description of the developed test section technology.

CERN Document Server

We discuss three distinct topics of independent interest; one in enumerative combinatorics, one in symmetric function theory, and one in algebraic geometry. The topic in enumerative combinatorics concerns a q-analog of a generalization of the Eulerian polynomials, the one in symmetric function theory deals with a refinement of the chromatic symmetric functions of Stanley, and the one in algebraic geometry deals with Tymoczko's representation of the symmetric group on the cohomology of the regular semisimple Hessenberg variety of type A. Our purpose is to explore some remarkable connections between these topics.

Energy Technology Data Exchange (ETDEWEB)

Ionization counters employing Bragg curve spectroscopy have been constructed for use in a 4{pi} geometry. These detectors compare very favorably in terms of both energy and charge resolution with small solid angle devices. These detectors have a large dynamic range because they are backed by scintillation detectors, and are thus capable of detecting and identifying particles with energies from 1 MeV/nucleon up to 200 MeV/nucleon. (orig.).

CERN Document Server

We consider a simple model of d families of scalar field interacting with geometry in two dimensions. The geometry is locally flat and has only global degrees of freedom. When d0 it collapses to a one dimensional manifold. The model has some, but not all, of the characteristics believed to be features of the full theory of conformal matter interacting with quantum gravity which has local geometric degrees of freedom.

Science.gov (United States)

A methodology and hypothetical case study are presented for incorporation of uncertainty and variability into calculations of human health risk appropriate for regional, or basin-scale, groundwater management problems. Uncertainty in well water concentration is introduced through complex contaminant migration patterns in the subsurface. Variability is considered in parameters related to individual behavior patterns and biological effects and to groundwater extraction and distribution networks. A joint uncertainty and variability (JUV) analysis is used to generate a two-dimensional distribution or risk surface that spans both transport uncertainty as well as individual variability. Cuts in this distributional surface (fractiles of variability and percentiles of uncertainty) are presented and discussed. Comparisons with alternative approaches based upon deterministic transport models ...

Energy Technology Data Exchange (ETDEWEB)

Region Lombardia has carried out a radon gas monitoring survey on its territory to localize radon prone areas as by law 241/00 enacted. To plan the survey, the Lombardia territory has been divided into two different types according to the morphology as well as the presence of a substratum of rock. The area with hills and mountains has been investigated with more attention compared to the plain because we can assume higher variability in radon concentration distribution due to the geological and morphological characteristics. The territory subdivision was based on the standard grid.. of the techniregional cartography (8 x 5 km). To perform radon indoor concentration measurements about 3600 measuring points were selected. They are located at the ground floor of buildings with the characteristics to ensure the tests are representative and comparable. It has also been taken into account evaluations done with previous surveys in accordance with the ...

Science.gov (United States)

Two branches of research are conducted in this thesis. The first deals with nonlinear combustion response as a mechanism for triggering combustion instabilities in solid rocket motors. A nonlinear wave equation is developed to study a wide class of combustion response functions to second-order in fluctuation amplitude. Conditions for triggering are derived from analysis of limit cycles, and regions of triggering are found in parametric space. Introduction of linear cross-coupling and quadratic self-coupling among the acoustic modes appears to be how the nonlinear combustion response produces triggering to a stable limit cycle. Regions of initial conditions corresponding to stable pulses were found, suggesting that stability depends on initial phase angle and harmonic content, as well as the composite amplitude, of the pulse. Also, dependence of nonlinear stability upon system parameters is considered. The second part of this thesis presents research for a controller to improve the ...

International Nuclear Information System (INIS)

In this paper, we report on a comparative study of active screen plasma nitriding (ASPN) and conventional dc plasma nitriding (CPN) behavior of 30CrNiMo8 low-alloy steel that has been examined under various process conditions. The process variables included active screen setup parameters (screen and iron plate top lids placed on the screen setup with 8 mm of hole size), treatment temperature (550 and 580 deg. C), gas mixture (75/25 and 25/75 of N_2/H_2) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the diffusion zone and compound layer were studied by X-ray diffraction (XRD), microhardness tests, light optical microscopy and scanning electron microscopy (SEM). It was observed that treated sample surfaces in both CPN and ASPN methods consist of #gamma#' and #epsilon# phases, and while the nitriding time and/or temperature increases, the intensity of #epsilon# phase in the compound layer will increase ...

International Nuclear Information System (INIS)

The process of infrared multiple photon dissociation (IRMPD) of molecules is of great fundamental importance and has practical significance, such as isotope separation etc. Unfortunately, a clear insight into the process has been hindered by the bewildering array of important variables affecting MPD. The dissociation probability #gamma#(#phi#) i.e. the yield has been found to be a sensitive function of laser fluence #phi# along with numerous other parameters like laser frequency, gas pressure etc. We have shown that in single frequency IRMPD an accurate quantitative characterization of the dissociation probability can be adequately expressed by a 'power law' model with two fitting parameters namely critical fluence, #phi#c and multi photon order, m. This model was exploited in analysing our MPD results on various systems. However, the small isotope shift encountered in heavy elements and the sticking phenomenon observed in small light molecules ...

Energy Technology Data Exchange (ETDEWEB)

The samples comprise the foliage of four pteridosperm-medullosalean plant fossil species of differing preservation states and one of a cordaitean species from two Canadian Maritime sub-basins of Carboniferous age (300 Ma; Sydney and Stellarton coalfields, Nova Scotia, respectively). Included in the sample set were some coal samples from Sydney Coalfield, along with published data for coal macerals for comparison. By applying Schulze's maceration process to the fossil foliage to obtain the cuticles, five sample forms evolved, viz. compressions, cuticles and fossilized cuticles, and acidic and alkaline solutions from Schulze's process, to which was added the Sydney coal samples as the sixth form. Area integration of the absorbance spectra from solid and liquid state Fourier transform infrared (FTIR) spectroscopy, produced functional chemical parameters which were organized into a data matrix of eight variables and 62 samples (8 x 62 matrix). ...

Science.gov (United States)

Ternary copper(II) complexes [Cu(L1)B](ClO4) (1, 2) and [Cu(L2)B](ClO4) (3, 4), where HL1 and HL2 are tridentate NSO- and ONO-donor Schiff bases and B is a heterocyclic base, viz. dipyrido[3,2-d:2',3'-f]quinoxaline (dpq, 1 and 3) or dipyrido[3,2-a:2',3'-c]phenazine (dppz, 2 and 4), were prepared and their DNA binding and photoinduced DNA cleavage activity studied. Complex 1, structurally characterized by single-crystal X-ray crystallography, shows an axially elongated square-pyramidal (4 + 1) coordination geometry in which the monoanionic L1 binds at the equatorial plane. The NN-donor dpq ligand exhibits an axial-equatorial binding mode. The complexes display good binding propensity to calf thymus DNA, giving a relative order 2 (NSO-dppz) > 4 (ONO-dppz) > 1 (NSO-dpq) > 3 (ONO-dpq). They cleave supercoiled pUC19 DNA to its nicked circular form when treated with 3-mercaptopropionic acid (MPA) by formation of hydroxyl radicals as the cleavage active species ...

International Nuclear Information System (INIS)

An overview is given the expected amount of natural gas that can be produced from small gas fields in the Netherlands in the next 20 years.

Energy Technology Data Exchange (ETDEWEB)

The origin of natural gas in the Japanese oil and gas fields are geochemically studied. Samples are taken from structural natural gas, surface gas seepage, water-dissolved natural gas and coal-field gas of the Japan Sea coast area. The origins of primary hydrocarbons are classified into bacteria gas and thermogenic gas, the latter being subclassified into gas in oil production zone with the per million deviation of the carbon isotope (/sup 13/C/sup 1/) of methane less than -35 and those gases with maturity higher than this. Surface gas seepage is subjected to migration and bacterial oxidation. Coal gas is similar to oil gas. The CO/sub 2/ concentration is 0 - 2% and /sup 13/CO/sub 2/ deviations from -30 - +30. The origin can be barely ...

Energy Technology Data Exchange (ETDEWEB)

A numerical package called RESID has been assembled to calculate the residual stresses in VAWT blades induced during cold forming. Using a strength of materials - elementary beam theory approach, RESID models the material response with a bilinear stress-strain curve, and the cross-sectional geometry with an array of area increments. Through an iterative solution procedure residual stresses are predicted for a specified final radius of curvature or applied bending moment. RESID results are compared to theoretical solutions for simple geometries and with MARC Finite element results for VAWT blade geometries. Calculating residual stress levels, determining acceptable residual stress levels, and a method of reducing residual stresses are discussed. A complete listing and sample run are included in the appendicies.

CERN Document Server

{The determination of cluster masses is a complex problem that would be aided by information about the cluster shape and orientation (along the line-of-sight).} {It is in this context, that we have developed a scheme for identifying the intrinsic morphology and inclination of a cluster, by looking for the signature of the true cluster characteristics in the inter-comparison of the different deprojected emissivity profiles (that all project to the same X-ray brightness distribution) and by using SZe data when available.} {We deproject the cluster X-ray surface brightness profile under the assumptions of four different geometry and inclination configurations for the observed system; these 4 configurations correspond to four extreme geometry+inclination scenarios. The deprojection in question is performed by the non-parametric algorithm DOPING. The formalism is tested with model systems and then is applied to a sample of 24 clusters. While the ...

International Nuclear Information System (INIS)

The work presented here demonstrates the ability of proton-transfer-reaction mass spectrometry (PTR-MS) to perform fast-response measurements of volatile organic compounds (VOCs) (including methanol, acetonitrile, acetaldehyde, acetone, PAN-type compounds, alpha- and beta-pinene, nopinone and pinonaldehyde) at the pptv level and its versatile applicability in the field of environmental trace gas analysis. Laboratory and field experiments including various calibration techniques and intercomparisons with other measurement techniques such as gas chromatography, atmospheric pressure chemical ionization and Fourier transformation infrared spectroscopy were performed providing a first characterization of the PTR-MS instrument performance (sensitivity, detection limit, precision, accuracy). Typically a detection limit (S/N=2) of 50 pptv for a 10 s signal integration time, a precision of 5 % and an accuracy in the range between 10 and 25 % were ...

Science.gov (United States)

Not Available

International Nuclear Information System (INIS)

Short communication.

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

... Accession Number : ADD419503. Title : Flue Gas Desulfurization and Low Btu Gasification - A Comparison Appendix G. ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

An exact cosmological solution of Einstein's equations which has time-dependent rotation is presented. The t-constant sections are of Bianchi type II. The source of this geometry is a fluid which has not been thermalized. (Author).

Energy Technology Data Exchange (ETDEWEB)

The two-phase heat-transfer and pressure-drop characteristics of offset-strip-fin heat-exchanger geometries are examined using both experimental and analytical modeling techniques. Newly-obtained boiling-flow heat-transfer data are presented for two large-scale offset fin geometries at low-to-moderate wall-superheat conditions. Data for which nucleate boiling appeared to be completely suppressed were analyzed together with similar results for other offset fin surfaces to study the effects of channel dimensions on the convective evaporation component of the local heat transfer coefficient. Although these data were found to be well correlated in terms of modified forms of the F and Martinelli parameters used in previous studies of round-tube flows, a single F-factor correlation valid for all combinations of fin and channel dimensions did not appear to exist. The two-phase pressure-drop characteristics of offset-fin surfaces were found to be much ...

UK PubMed Central (United Kingdom)

BackgroundA relevant problem in drug design is the comparison and recognition of protein binding sites. Binding sites recognition is generally based on geometry often combined with...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

This research investigates the impact of national culture and several institutional factors on the safety performance of society and establishes statistically significant relationships between those variables. As expected, the research results reveal that some cultural variables such as uncertainty avoidance, gender orientation and institutional variables such as the degree of law avoidance can directly influence the safety performance of the society. The findings also support the inverted u-curve (Safety Kuznet curve) hypothesis indicating even if we expect a negative trend at the beginning stage of industrialization, we can expect a positive trend in safety performance as their income level continues to improve beyond a certain point.

Energy Technology Data Exchange (ETDEWEB)

Creep properties of modified 9 Cr-1 Mo steel, an alloy significantly improved in elevated-temperature strength over 2 1/4 Cr-1 Mo and other similar alloys, are presented here. Data are primarily on material in the normalized and tempered condition. Effects of variables such as isothermal annealing treatment, cold work, normalizing temperature, tempering temperature, notch, and biaxial stress state have also been examined. Data analysis and comparisons have shown that modified 9 Cr-1 Mo alloy is very insensitive in response to several material variables, heat treatments, and specimen design variables.

Energy Technology Data Exchange (ETDEWEB)

The relationship between short term relative sea-level oscillations and the reef, off-reef deposits geometry of an Upper Devonian third order sequence highstand of the Nisku Formation in west central Alberta was studied through the analysis of high resolution sequence stratigraphy. Hydrocarbon generation was reconstructed by total organic carbon values and migration patterns that were dependent on the geometry of three fourth order sequences. This stratigraphic reconstruction provided the key to recent hydrocarbon discoveries such as in the Brazeau southern reef margin.

Science.gov (United States)

Self-magnetically insulated, high-voltage transmission lines are used in inertial confinement fusion particle accelerators in order to transmit power from the vacuum insulator to the diode. This paper describes a time-dependent 2-D code (MITL) for calculating (for planar or triplate geometries) the motion of test electrons through the tapered input or output convolutes of such lines. MITL results show that the electron canonical momentum in the direction of the flow changes as the electron passes through the convoluted geometry; it is suggested that these electrons lead to losses observed in long self-magnetically insulated lines.

Energy Technology Data Exchange (ETDEWEB)

The concentric circular annular duct is a common geometry in many fluid flow and heat transfer devices. For the purpose of heat transfer augmentation, fins are often employed in the annular region, and such finned ducts find wide application in compact heat exchangers (5, 6). The analysis of flow and heat transfer in this geometry is, therefore, quite important from an engineering standpoint. For fully developed conditions, the problem has already been analyzed (7-10). However, no results are available for the developing flow in the entrance region. It is with this latter problem that the present paper is concerned.

UK PubMed Central (United Kingdom)

Background and ObjectivePulsed dye laser (PDL) treatment of cutaneous vascular lesions is associated with variable and unpredictable efficacy. Thus, alternative treatment...Full Text Available

International Nuclear Information System (INIS)

The fatigue life variability of the #alpha#+#beta# titanium alloy, Ti-6Al-2Sn-4Zr-6Mo increased with decreasing stress level. The variability in life was found to be due to segregation of lives due to two failure mechanisms. A bimodal cumulative distribution model was shown to accurately describe the combined failure modes. The nominal failure processes for the two regimes were similar, with crack nucleation occurring in equiaxed #alpha#p particles, irrespective of life or stress level. However the variability in life was not controlled by the size of the crack-nucleating #alpha#p, but rather by the ability of the material to distribute deformation and avoid early crack nucleation.

Science.gov (United States)

... and operation of marine structures and to estimate coastal sediment transport. While the timely collection and report of high ... ...

UK PubMed Central (United Kingdom)

Brains are usually described as input/output systems: they transform sensory input into motor output. However, the motor output of brains (behavior) is notoriously variable, even under identical sensory...Full Text Available

CERN Document Server

In this paper we present a complete solution to the problem of multifractal analysis of multiple ergodic averages in the case of symbolic dynamics for functions of two variables depending on the first coordinate.

Science.gov (United States)

Jul 25, 2011 ... Koji Mukai's Bibliography. Invited Reviews. Mukai, K. 1994, "ASCA PV Phase Observations of Cataclysmic Variables," in "New Horizon of X-ray ...

UK PubMed Central (United Kingdom)

Background and AimsAnnonaceae are one of the largest families of Magnoliales. This study investigates the comparative floral development of 15 species to understand the basis for...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Knowledge on environmental variability and how it is affected by disturbances is crucial for understanding patterns of biodiversity and determining adequate conservation strategies. The aim of this study is to assess environmental variability in patches undergoing post-fire vegetation recovery, identifying trends of change and their relevant drivers. We particularly evaluate: the value of three spectral indices derived from Landsat satellite data [Normalized Burn Ratio (NBR), Normalized Difference Vegetation Index (NDVI) and Wetness Component of the Tasseled Cap Transformation (TCW)] for describing secondary succession; the effectiveness of three metrics (diversity, evenness and richness) as indicators of patch variability; and how thematic resolution can affect the perception of environme...

British Library Electronic Table of Contents (United Kingdom)

Climate variability greatly affects animals through direct and indirect effects. Animals with slow reproductive adaptation to ecological changes such as large mammals are likely to have evolved mechanisms to anticipate early such impacts of climate variability on the environment. One of the adaptive mechanisms between reproductive costs and benefits in mammals affects parental investment through biases in sex ratio. Deer might be likely to show an early detection of climate variability because conception takes place in early autumn, but the main raising cost in deer concerns lactation, which takes place at the end of the following spring. The aim of this paper is to assess whether there is a relationship between global indices of climate variability such as El Ni?o-Southern Oscillation (EN...

UK PubMed Central (United Kingdom)

The study of genetic variability within natural populations of pathogens may provide insight into their evolution and pathogenesis. We used a Mycobacterium tuberculosis high-density...Full Text Available

Science.gov (United States)

measure meteorological variables and bulk water temper- ature. The locations of the buoys are given in Table 1. TB2 and TB3 were moved slightly farther south ...

Science.gov (United States)

... Direct Search (SMOMADS) and Paciencia's NMADS [45] based on Kim and de Weck's ... Todd Paciencia for his foundational contributions. ...

Energy Technology Data Exchange (ETDEWEB)

The most effective way to generate electricity out of biomass is the gasification and the use of the gas in a gas engine. The conversion of the organic carbon with the gasification of biomass is higher than 95 %. Depending on the gasification concept, the efficiency of gasifiers is found between 70 and 90 %. If the pyrolysis gas is used in a gas engine, an electric efficiency of about 26 % referring to the primary amount of energy can be obtained. With efficient gas cleaning (cleaning for tar and dust), pyrolysis gas is well qualified for engine combustion. Through modern state of engine controlling there are ways to have complete control of the fluctuations in the gas composition. Furthermore, the minor calorific value of offered wood gas poses no problem for turbo charged lean-burn gas engines. ...

Science.gov (United States)

Appendices to this summary consist of twelve individual status reports that will be available through the National Technical Information Service (NTIS) in the United States and of course limited copies will be available through NATO. The twelve report titles which are appendices to the summary are: (A) Status Report on the Limestone/Sludge Flue Gas Desulfurization Process; (B) Status Report on the Lime/Sludge Flue Gas Desulfurization Process; (C) Status Report on the Double Alkali/Sludge Flue Gas Desulfurization Process; (D) Status Report on the Sea Water Scrubbing Flue Gas Desulfurization Process; (E) Status Report on the Limestone/Gypsum Flue Gas Desulfurization Process; (F) Status Report on the Lime/Gypsum Flue Gas Desulfurization Process; (G) Status Report on the Double Alkali/Gypsum Flue Gas Desulfurization Process; (H) Status Report on ...

Energy Technology Data Exchange (ETDEWEB)

This book discusses the progress and problems of current interest in gaseous dielectrics and their use, with special emphasis on insulation in high-voltage transmission lines and substations. Topics covered include: basic physics of gaseous dielectrics; basic mechanisms; gas decomposition, reactions and toxicity; diagnostics and field probes; gases and mixtures for GIS transformers and circuit breakers; gaseous media for discharge chemistry and etching/corona; gas engineering for pulsed power and switching; gas breakdown under steep-fronted voltages; new developments in gas-insulated equipment and gas handling; gas/insulator interface/flashover; and quality control in testing gas-insulated equipment. Contains approximately 85 papers.

Energy Technology Data Exchange (ETDEWEB)

Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. While methane, propane, and other gases can be included in the clathrate structure, methane hydrates appear to be the most common in nature. The amount of methane sequestered in gas hydrates is probably enormous, but estimates are speculative and range over three orders of magnitude from about 100,000 to 270,000,000 trillion cubic feet. The amount of gas in the hydrate reservoirs of the world greedy exceeds the volume of known conventional gas reserves. Gas hydrates also represent a significant drilling and production hazard. A fundamental question ...

Energy Technology Data Exchange (ETDEWEB)

Synthesis of silver nanoparticles based on a polyol process and variable frequency microwave (VFM) was investigated. Comparing to a thermal method, the reaction by VFM radiation was much faster. The effects of silver nitrate concentration, poly(N-vinylpyrrolidone) (PVP) concentration, reaction time and reaction temperature were studied. It was found that the higher concentration of silver nitrate, longer reaction time and higher temperature increased the particle size while the higher concentration of PVP decreased the particle size.

International Nuclear Information System (INIS)

In the case of large capacity steam turbines the conventional nozzle group control is, for mechanical and thermodynamic reasons, diminishing more and more in importance in favour of variable pressure control. A design for constant-pressure operation as an alternative to nozzle group control is described; this demonstrates a series of important advantages compared with the latter. (orig.).

Energy Technology Data Exchange (ETDEWEB)

This book contains the Proceedings of the Conference on Climate and Water under the following groupings: Impacts of climatic variability and change-resulting from the changes in hydrological variables; Aquatic environment; Terrestrial environment; Coastal zones and navigation; Urban and industrial water supply and drainage; Energy production; Intropogenic changes of climate and water management problems; Flood potential; Irrigation and land drainage.

Energy Technology Data Exchange (ETDEWEB)

The effect of fetal distress on the neonatal brain was investigated by neonatal CT brain scan, FHR monitoring and mode of delivery. This study involved 11 cases of full term vertex delivery in which FHR was recorded by fetal direct ECG during the second stage labor. All infants weighed 2,500 g or more. FHR monitoring was evaluated by Hon's classification. Neonatal brain edema was evaluated by cranial CT histgraphic analysis (Nakada's method). 1) Subdural hemorrhage was noted in 6 of 7 infants delivered by vacuum extraction or fundal pressure (Kristeller's method). 2) Intracranial hemorrhage was demonstrated in all of 3 infants with 5-min. Apgar score 7 or less. 3) Two cases with prolonged bradycardia and no variability had intraventricular or intracerebral hemorrhage which resulted in severe central nervous system damage. 4) The degree of neonatal brain edema correlated with 5-min. Apgar score. 5) One case with prolonged bradycardia and ...

Energy Technology Data Exchange (ETDEWEB)

The situation of natural gas in the Federal Republic of Germany is described, with particular emphasis on the advantages and consequences of natural gas supply. The brochure discusses the role of natural gas on the energy market, the reliability of natural gas supply, the environmental impacts, the energy-saving effect of natural gas, natural gas prices, the competitive strength of the German gas industry, and the long-term reliability of natural gas supply. (orig.) [German] Die Situation des Erdgases in der Bundesrepublik Deutschland wird beschrieben, wobei die wichtigsten Vorteile und Auswirkungen der Erdgasversorgung besonders hervorgehoben werden. Es geht um die Stellung des Erdgases im Energiemarkt, die Sicherheit der Energieversorgung, Umweltschutz, Energieeinsparung durch Erdgaseinsatz, Erdgaspreise, ...

Energy Technology Data Exchange (ETDEWEB)

The genetic type, source and charging history of natural gas in the Yulin gas field in the Ordos Basin have been studied by combining the carbon isotopic composition of natural gas and geochemical characteristics of light hydrocarbons with carbon isotope fractionation model results and fluid inclusion analysis. The carbon isotopic composition of methane and ethane in the Yulin gas field is relatively enriched in {sup 13}C with {delta}{sup 13}C{sub 1} values ranging from - 35.3 permille to - 29.8 permille (average value = - 32.4 permille) and {delta}{sup 13}C{sub 2} ranging from - 26.3 permille to - 23.5 permille (average value = - 24.8 permille). The C{sub 7} light hydrocarbons are predominated by methylcyclohexane, accounting for 65.8% to 80.9% (average value = 71.6%), which is characteristic of coal-derived gas. Furthermore, the gas geochemistry indicates ...

Energy Technology Data Exchange (ETDEWEB)

A combined gas/steam turbine process includes a high-pressure furnace and a high pressure gasification unit with a mounted upstream of a combustion chamber there is a gas turbine with a waste heat system. Combustion heat which is not needed to heat the flue gas to combustion temperature is released from the furnace and transferred to ths combustion air going into the combustion chamber.

Energy Technology Data Exchange (ETDEWEB)

The budding natural gas markets in East Europe attract a great deal of interest from natural gas industries in the Western countries. Dutch companies, institutions and the government, too, are active in this market. So far the results have not been spectacular. An analysis is made of the present situation and the Dutch approach

International Nuclear Information System (INIS)

Natural gas is essential to the world economy. Gas now accounts for almost a quarter of OECD primary energy requirements and is expected to become the second most important fuel in the world in the next decade. Industrial and residential consumers increasingly rely on natural gas to keep their houses warm, their lights on and their factories running. Meanwhile the gas industry itself has entered a new phase. Where gas used to be restricted to regional markets, it is now increasingly traded on a global scale. While gas production and transport requires long-term investment, now it is optimised on a short-term basis. Demand continues to grow, but local gas production has become much more expensive. How should we react? How will demand be satisfied? What changes are required to promote flexibility and trade? What are the implications for ...

Science.gov (United States)

The purpose of this project was to build a long-range, parallel hybrid gas/electric vehicle capable of driving beyond the communter capabilities of series hybrid vehicles. It was envisioned that since the gas engine would be able to independently propel t...

Energy Technology Data Exchange (ETDEWEB)

Lateral and vertical variabilities in the bulk and mechanical properties of silicic volcanic tuff at the potential nuclear waste repository site in Yucca Mountain, NV have been evaluated. Laboratory measurements have been performed on tuff specimens recovered from boreholes located to support the design of the Exploratory Studies Facility/North Ramp. The data include dry and saturated bulk densities, average grain density, porosity, compressional and shear wave velocities, elastic moduli, and compressional and tensional fracture strengths. Data from eight boreholes aligned in a northwest-southeast direction have been collected under the required quality assurance program. Three boreholes have penetrated the potential repository horizon. The information collected provides for an accurate appraisal of the variability of rock properties in the vicinity of the boreholes. As expected, there is substantial variability in the bulk ...

Energy Technology Data Exchange (ETDEWEB)

The sedimentary geometry is determined by several types of stratigraphic surfaces: transgressive surfaces (TS), maximum flooding surfaces (MFS) and downward shift surfaces (DS). They are organized hierarchically into major and minor surfaces from the facies stacking-pattern. These surfaces which are observable on well logs and cores structure the sedimentary architecture and are, therefore, the best candidates to form major seismic reflectors. The well (logs and cores) to seismic (surface seismic) passage involves inherently a change of observation scale. That is from a high resolution sequence stratigraphy (metric to pluri-metric) to a sequence stratigraphy s.l. (decametric to pluri-decametric). This passage is composed of two phases. The first phase consists of the validation of density and sonic logs whose product corresponds to the acoustic impedance. The second phase allows for the modelling of the geological cross section of a field in a synthetic seismic ...

CERN Document Server

In dissipative ordinary differential equation systems different time scales cause anisotropic phase volume contraction along solution trajectories. Model reduction methods exploit this for simplifying chemical kinetics via a time scale separation into fast and slow modes. The aim is to approximate the system dynamics with a dimension-reduced model after eliminating the fast modes by enslaving them to the slow ones via computation of a slow attracting manifold. We present a novel method for computing approximations of such manifolds using trajectory-based optimization. We discuss Riemannian geometry concepts as a basis for suitable optimization criteria characterizing trajectories near slow attracting manifolds and thus provide insight into fundamental geometric properties of multiple time scale chemical kinetics. The optimization criteria correspond to a suitable mathematical formulation of "minimal relaxation" of chemical forces along reaction trajectories under ...

International Nuclear Information System (INIS)

It is very well known that the CANDU reactor has positive Coolant Void Reactivity (CVR), which is most important criticisms about CANDU. The most recent innovations based on using a thin absorbent Hafnium shell in the central bundle element were successfully been applied to the Advanced CANDU Reactor (ACR) project. The paper's objective is to analyze elementary lattice cell effects in applying such methods to reduce the CVR. Three basic fuel designs in their corresponding geometries were chosen to be compared: the ACR-1000TM, the RU-43 (developed in INR Pitesti) and the standard CANDU fuel. The bundle geometry influence on void effect was also evaluated. The WIMS calculations proved the Hafnium absorber suitability (in the latest 'shell design') to achieve the negative CVR target with great accuracy for the ACR-1000 fuel bundle design than for the other two projects. (authors)

International Nuclear Information System (INIS)

As a three-year joint university-industry effort, development of a generalized boiling transition analysis method has been started in 2002 aiming at enhanced capabilities of subchannel analysis for a wide variety of BWR-type fuel bundle geometry from ordinary BWR to tight lattice fuel bundles. For this purpose, five dominant factors affecting boiling transition phenomena have been identified on which our efforts of experimentation and numerical analyses are focused. In this report, as the first-year achievement, we will describe a master plan of the development and contents for experimental approaches to construct thermal-hydraulic databases. The databases will be utilized for the developments of constitutive equations to describe the basic characteristics of the elementary processes. The planned experiments are divided into two groups. One is air-water experiments at atmospheric pressure, and the other is steam-water experiments up to 1 MPa. The former group of ...

Science.gov (United States)

... Accession Number : ADD135818. Title : Performance of Titanium in Flue Gas Desulfurization Scrubber Systems,. Descriptive Note : Journal Article,. ...

Energy Technology Data Exchange (ETDEWEB)

A new surveillance system for Oil-Filled cable, which can provide continuous monitoring, using a newly developed optical gas sensor that can detect the concentration of the gas dissolved in the oil with extremely high sensitivity has been developed. It was proved that the degree of deterioration of the insulating oil can be detected by measuring C{sub 2}H{sub 2} and CH{sub 4} by investigating the relation between the degree of deterioration and amount of combustible gas generated. In order to detect extremely small amounts of gas, a new gas detecting method using absorption line of the gas using a frequency modulated technique has been developed. The gas detection ability was also confirmed by examination using a 66 kV of cable and the possibility of detection at an early stage is expected.

UK PubMed Central (United Kingdom)

The oxygen production of a photosynthetic gas exchanger containing Chlorella pyrenoidosa (1% packed cell volume) was measured when various concentrations of carbon dioxide were present...Full Text Available

Science.gov (United States)

... Accession Number : ADA089146. Title : Flue Gas Desulfurization at Navy Bases, Navy Energy Guidance Study. Phase IV. ...

Energy Technology Data Exchange (ETDEWEB)

Tests to measure the maximum horsepower of commercial vehicles converted for use with natural gas fuel indicate a reduction of approximately 20% in horsepower compared with gasoline-driven vehicles. This reduction in horsepower resulting from the use of gas is due basically to the lower thermal efficiency of the cycle of natural gas compared with that of gasoline and to its lower volumetric efficiency, since natural gas is injected into the combustion chamber in gaseous form, unlike gasoline, in which part of the fuel entering the cylinder is in the liquid phase. Natural gas used as a fuel generates lower quantities of air pollutants, particularly unburned hydrocarbons (HCs) and carbon monoxide (CO). Despite the downside of reduced horsepower, the use of natural gas as a fuel for automotive vehicles equipped with Otto-cycle engines is economically viable owing ...

Science.gov (United States)

... Accession Number : ADA092132. Title : Analysis of Flue Gas Desulfurization (FGD) Processes for Potential Use on Army Coal-Fired Boilers. ...

British Library Electronic Table of Contents (United Kingdom)

Diet overlap and niche breadth are well-known species traits from trophic ecology that can assist in explaining how species interact and coexist as well as the ecological mechanisms that influence biodiversity. In the present study, we analyzed the relationships between these trophic variables and indicators of resource availability with some attributes of fish assemblages (species richness, Shannon diversity index, evenness, density and individual body size). The physical and chemical characteristics of the biotopes (topography, water quality and conservation of slopes) were examined to identify possible patterns. Monthly sampling using electrofishing was conducted in 2003 along five streams located in the Cuiab? River watershed. The relationships between environmental variables and attri...

CERN Document Server

The unavoidable irreversible losses of power in a heat engine are found to be of quantum origin. Following thermodynamic tradition a model quantum heat engine operating by the Otto cycle is analyzed. The working medium of the model is composed of an ensemble of harmonic oscillators. A link is established between the quantum observables and thermodynamical variables based on the concept of canonical invariance. These quantum variables are sufficient to determine the state of the system and with it all thermodynamical variables. Conditions for optimal work, power and entropy production show that maximum power is a compromise between the quasistatic limit of adiabatic following on the compression and expansion branches and a sudden limit of very short time allocation to these branches. At high temperatures and quasistatic operating conditions the efficiency at maximum power coincides with the endoreversible result. The optimal ...

British Library Electronic Table of Contents (United Kingdom)

The primary objective of batch data as trajectory alignment (or synchronization) is to standardize the data sampling per batch according to the evolution of the process, and secondarily to homogenize the samples per run. The use of an indicator variable performs both objectives well. Two examples from the pharmaceutical sector are discussed to illustrate the different ways to deal with uneven samples across batches and across variables in the same batch. Since trajectory alignment requires large time investment, a simple triage approach is proposed to assess the need to analyze the dynamics of a given process and hence perform alignment. The presented examples are representative of a broad variety of batch processes that are operated by recipe in the pharmaceutical sector. In our experienc...

CERN Document Server

An interesting line of research is the investigation of the laws of random variables known as Dirichlet means. However, there is not much information on interrelationships between different Dirichlet means. Here, we introduce two distributional operations, one of which consists of multiplying a mean functional by an independent beta random variable, the other being an operation involving an exponential change of measure. These operations identify relationships between different means and their densities. This allows one to use the often considerable analytic work on obtaining results for one Dirichlet mean to obtain results for an entire family of otherwise seemingly unrelated Dirichlet means. Additionally, it allows one to obtain explicit densities for the related class of random variables that have generalized gamma convolution distributions and the finite-dimensional distribution of their associated L\\'{e}vy processes. ...

CERN Document Server

The central engine of Gamma Ray Bursts is hidden from direct probing with photons mainly due to the high densities involved. Inferences on their properties are thus made from their cosmological setting, energetics, low-energy counterparts and variability. If GRBs are powered by hypercritical accretion onto compact objects, on small spatial scales the flow will exhibit fluctuations, which could in principle be reflected in the power output of the central engine and ultimately in the high energy prompt emission. Here we address this issue by characterizing the variability in neutrino cooled accretion flows through local shearing box simulations with magnetic fields, and then convolving them on a global scale with large scale dynamical simulations of accretion disks. The resulting signature is characteristic, and sensitive to the details of the cooling mechanism, providing in principle a discriminant for GRB central engine properties.

British Library Electronic Table of Contents (United Kingdom)

This paper presents a study on Manasbal lake, which is one of the high altitude lakes in the Kashmir Valley, India. Eighteen water samples were analysed for major ions and trace elements to assess the variability of water quality of the lake for various purposes. Geostatistics, the theory of regionalized variables, was then used to enhance the dataset and estimate some missing spatial values. Results indicated that the concentration of major ions in the water samples in winter was higher than in summer. The scatter diagrams suggested the dominance of alkaline earths over the alkali elements. Three types of water were identified in the lake that are referred to as Ca?HCO3, Mg?HCO3 and hybrid types. The lake water was found to be controlled by rock?water interaction with carbonate lithology ...

International Nuclear Information System (INIS)

A variable gene delivery system has been developed based on conjugating chitosan to biotin through a functionalized poly(ethylene glycol) (PEG) spacer, which can be used to further bind different molecules on the outer layer of a polymer/DNA complex by streptavidin (SA)-biotin linkage. In this study, TAT-conjugated SA was used as the model molecule to prove the conjugation function of the prepared complex. In addition, low-molecular-weight poly(ethyleneimine) (PEI) was added into the polymer/DNA complex to increase the transfection efficiency. The results of the luciferase assay show that the transfection efficiency of the prepared complex was significantly correlated with the amount of PEI and was further enhanced when TAT was conjugated to the complex by SA-biotin linkage. Considered to have negligible cytotoxic effects, the variable gene delivery complex prepared in this study would be of considerable potential as carriers for in vitro ...