CERN Document Server

The emission of the plerion G21.5-0.9 appears more extended in X rays than in radio. This is an unexpected result because it would imply that short-lived X-ray electrons may reach distances even larger than radio electrons. Applying an empirical relationship between dust scattering optical depth and photoelectric column density, the measured column density leads to a large optical depth at 1 keV, of about 1. Therefore we investigate the hypothesis that the detected halo be an effect of dust scattering, re-analyzing an Cal/PV XMM-Newton observation of G21.5-0.9 and critically examining it in terms of a dust scattering model. We also present a spectral analysis of a prominent extended feature in the northern sector of the halo.

Energy Technology Data Exchange (ETDEWEB)

In order to clarify a mechanism of melt-jet breakup and fragmentation entirely different from the mechanism of stripping, a series of experiments were carried out by using molten tin jets of 100 grams with initial temperatures from 250degC to 900degC. Molten tin jets with a small kinematic viscosity and a large thermal diffusivity were used to observe breakup and fragmentation of melt jets enhanced thermally and hydrodynamically. We observed jet columns with second-stage large-scale structures generated by the coalescence of large-scale structures recognized in the field of fluid mechanics. At a greater depth, the segmentation of jet columns between second-stage large-scale structures and the fragmentation of the segmented jet columns were observed. It is reasonable to consider that the segmentation and the fragmentation of jet columns are caused by the boiling of water ...

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The performance of five well-known photosynthesis-light equations is compared by presenting a wide range of solutions in the form of dimensionless nomographs for the case where photosynthetically available radiation (PAR) reduces exponentially down the water column and is distributed sinusoidally through the photoperiod. These provide a simple means of calculating daily photosynthesis at any depth (e.g. at a benthic layer), or through a water column, avoiding the need to perform complex integrations. An examination is made of the accuracy of common approximate methods for calculating daily photosynthesis, assuming constant PAR. For optically deep water a modification is proposed to Talling's planimetric solution, to enable daily photosynthesis to be calculated more accurately, yet simply, over the whole range of possible PAR values. The errors induced by approximating the daily PAR distribution as a half-sinusoid ...

Energy Technology Data Exchange (ETDEWEB)

Concentrations of {sup 239+240} Pu and {sup 137} Cs were measured for vertical direction and horizontal direction in seawater collected at 21 locations on the 8 directions near Wolsung nuclear power plant. The inventories of {sup 239+240} Pu and {sup 137} Cs were calculated in seawater column. The concentrations of {sup 239+240} Pu and {sup 137} Cs were in seawater in the range of 8-36 {mu}Bq/L, 2.4-4.5 mBq/L, respectively. The {sup 239+240} Pu concentration increased with depth, however, the {sup 137} Cs concentrations not greatly changed with depth above thermocline.

International Nuclear Information System (INIS)

We have synthesized ozone by irradiating thin solid films of oxygen and oxygen-water mixtures with 100 keV protons, motivated by recent reports of condensed O_3 on icy satellites in the outer Solar system. We measured the depth of the Hartley absorption band in the ultraviolet by reflectance spectroscopy and used it to quantify the column density of ozone. We analyzed the results using a three-component (O, O_2 and O_3) model that successfully explains the fluence dependence of ozone production.

KoreaScience (Korea)

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Science.gov (United States)

... TANK GUNS, GUNS, CHAMBERS, IGNITERS, INTERIOR BALLISTICS, INTERNAL PRESSURE, COMBUSTIBLE CARTRIDGE CASES, METALS. ...

Energy Technology Data Exchange (ETDEWEB)

A micronized de-ashed coal-water slurry (CWS) fuel of approximately 50% coal loading has been successfully ignited and burned in one GE 7FDL engine cylinder at 1050 rpm. For this study, only about one-third of the full load fuel energy was supplied due to limitations of the fuel injection equipment used. Three types of ignition methods have been investigated. They were: Compression ignition with no ignition aid; Separate deisel pilot fuel injection to ignite the CWS fuel; Combined CWS and pilot diesel fuel injection (stratified pilot ignition). Conditions of ignition and the burning characteristics that immediately followed using the above three ignition methods are described.

Energy Technology Data Exchange (ETDEWEB)

The impact of a mixture of oxytetracycline, chlortetracycline, tetracycline and doxycycline on Myriophyllum sibiricum and Lemna gibba was investigated using fifteen 12,000-L microcosms (k = 5, n = 3). Significant concentration-response relationships were only found for M. sibiricum, where dry mass was 69, 47, 30, and 7% of controls at respective treatment concentrations of 0.080, 0.218, 0.668, and 2.289 {mu}mol/L. Somatic endpoints were strongly and negatively correlated with percent light transmission, except plant length, which was positively correlated. Treated microcosms experienced a reduction in the percent of surface irradiance penetrating the water column as high as 99.8% at a depth of 70 cm, relative to controls. Position relative to the water column was likely responsible for the differential effects observed between floating (L. gibba) and submerged (M. sibiricum) species of macrophytes. A hazard quotient ...

British Library Electronic Table of Contents (United Kingdom)

A microcosm laboratory experiment was conducted to determine the impact of biological reworking by the ragworm Nereis diversicolor on the redistribution of particle-bound radionuclides deposited at the sediment-water interface. Over the course of the 40-day experiment, as much as 35% of a 137Cs-labelled particulate tracer deposited on the sediment surface was redistributed to depths of up to 11 cm by the polychaete. Three different reworking models were employed to model the profiles and quantify the biodiffusion and biotransport coefficients: a gallery-diffuser model, a continuous sub-surface egestion model and a biodiffusion model. Although the biodiffusion coefficients obtained for each model were quite similar, the continuous sub-surface egestion model provided the best fit to the data...

Energy Technology Data Exchange (ETDEWEB)

The plasma plume generated by a new type of high energy Janitor known as the railplug, is examined. The railplug is a miniaturized railgun that has the potential for improving ignition characteristics of combustible mixtures in engines. The objective of the study is to gain an uderstanding of the characteristics of the plasma created by a transparent railplug, and to validate a multidimensional computer simulation of the plasma and shock fronts. The nature of the plume emitted by the railplug was examined for three levels of electrical energy while firing into air at a pressure of 1 atm. The computer model is to be used to predict trends in railplug performance for various railplug designs, energies, and ambient conditions. The velocity of the plasma movement inside a transparent railplug was measured, as well as the velocity of the plume ejected from the cavity. A shock is produced at the initiation point of the arc and propagates down the cavity, eventually ...

Science.gov (United States)

Dissolved organic substances derived from forest litter are believed to influence the retention and movement of SO{sub 4}{sup 2{minus}} in forest soils. A column study was conducted in which {sup 35}SO{sub 4} was surface applied to a soil and leached with either low-molecular-weight aliphatic acids (AA) or a forest-litter extract. Oxalic, malonic, and succinic acids were used in the concentration range 8.0 {times} 10{sup {minus}3} to 1.0 {times} 10{sup {minus}5} mol L{sup {minus}1}. Movement of {sup 35}SO{sub 4} was determined with column depth, as was the {sup 35}SO{sub 4} activity in the collected leachates. Labeled SO{sub 4} soil movement was found to increase with increasing AA concentration. Leachate {sup 35}SO{sub 4} activity was observed to increase in the order malonic > succinic > oxalic for acid treatments > 1.0 {times} 10{sup {minus}4} mol L{sup {minus}1}. The 1.0 {times} 10{sup {minus}5} mol L{sup ...

Science.gov (United States)

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Norwegian Open Research Archives (NORA)

Full Text Available

Science.gov (United States)

... TEMPERATURE, PRESSURE MEASUREMENT, GUN CHAMBERS, COMPACTING, COMBUSTIBLE CARTRIDGE CASES, FLASH RADIOGRAPHY ...

Energy Technology Data Exchange (ETDEWEB)

X-ray ablation of material from the first wall and other components of an ICF (Inertial Confinement Fusion) chamber is a major threat to the laser final optics. Material condensing on these optics after a shot may cause damage with subsequent laser shots. To ensure the successful operation of the ICF facility, removal rates must be predicted accurately. The goal for this dissertation is to develop an experimentally validated x-ray response model, with particular application to the National Ignition Facility (NIF). Accurate knowledge of the x-ray and debris emissions from ICF targets is a critical first step in the process of predicting the performance of the target chamber system. A number of 1-D numerical simulations of NIF targets have been run to characterize target output in terms of energy, angular distribution, spectrum, and pulse shape. Scaling of output characteristics with variations of both target yield and hohlraum wall thickness are also described. ...

CERN Document Server

The problem of model selection arises in a number of contexts, such as subset selection in linear regression, estimation of structures in graphical models, and signal denoising. This paper generalizes the notion of "incoherence" in the existing literature on model selection and introduces two fundamental measures of coherence---termed as the worst-case coherence and the average coherence---among the columns of a design matrix. It utilizes these two measures of coherence to provide an in-depth analysis of two variants of a simple one-step thresholding (OST) algorithm for model selection and proves that OST is feasible for model selection as long as the design matrix obeys an easily verifiable property. One of the key insights offered by the ensuing analysis in this regard is that if the design matrix has reasonably small worst-case and average coherence then OST performs near-optimally when either (i) the energy of any nonzero entry of the ...

International Nuclear Information System (INIS)

Several configurations of moderating and shielding materials have been designed and measured on the LVR-15 reactor for boron neutron capture therapy (BNCT) purposes. To determine the neutron and gamma ray space-energy distributions in the cylindrical geometry, the two-dimensional code DOT with the coupled neutron-gamma data library DLC-36 was used. The experimental verification of the beam parameters was performed in the LVR-15 reactor thermal column empty space with layers of graphite, aluminium, alumina, lead and bismuth. Attention was paid to establishing techniques and instrumentation for monitoring the neutron and gamma ray dose and beam quality. The thermal and epithermal flux densities were measured by activation foils, the neutron spectrum was determined with a Bonner spectrometer and gamma ray background with a scintillation spectrometer. The distribution of thermal neutrons in the human head phantom was mapped with a small semiconductor detector (Si"6Li). ...

Science.gov (United States)

... CHANNELS, TWO PHASE FLOW, WAVES, IGNITERS, GAS FLOW, HOWITZERS, CARTRIDGE CASES, COMBUSTIBLE CARTRIDGE CASES. ...

Energy Technology Data Exchange (ETDEWEB)

The idle speed of an internal combustion engine is controlled in response to a variable ignition timing control signal from a microcomputer. The microcomputer derives this control signal as a function of the magnitude of engine speed variation which occurs during engine idle periods to cause the ignition timing to vary quickly in response to a transitory engine load variation. An auxiliary air delivery system may be advantageously incorporated in the idle speed control system to cooperate with the ignition timing control in response to the engine speed variation.

Energy Technology Data Exchange (ETDEWEB)

Tests have been conducted on a special compression ignition research engine to investigate the effects of gaseous fuels on the ignition delay in dual fuel engines. Diesel oil, n-heptane, or cetane were used as pilot fuels, and hydrogen, carbon monoxide, or methane were inducted in the intake manifold. Induction of nitrogen was used as a reference to eliminate the influence of changes in oxygen concentration and specific heats. Helium was inducted in additional tests. From the results of a number of parameter variations, the cylinder charge temperature (determined by intake temperature and compression ratio), the pilot fuel amount, and the flow of combustible gas were found to have the most significant influence on the ignition delay.

Science.gov (United States)

... COMPUTERIZED SIMULATION, MOLDINGS, PROPELLANT GRAINS, IGNITION, COMBUSTIBLE CARTRIDGE CASES, COMBUSTION, HEAT ...

Energy Technology Data Exchange (ETDEWEB)

This paper introduces in detail the compression performance of biogas, the application of compressed biogas to the compression-ignition engine and the possibility as well as the necessity of using compressed biogas. Moreover, the paper also goes further into some problems about the power increasing, efficiency raising and their social, economic and ecological beneficial results, when the compressed biogas is used in the compression ignition-dual fuel engine.

KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

The Ames autotracking airborne sun photometer was used to investigate the spectral depth between 380

International Nuclear Information System (INIS)

A microcosm laboratory experiment was conducted to determine the impact of biological reworking by the ragworm Nereis diversicolor on the redistribution of particle-bound radionuclides deposited at the sediment-water interface. Over the course of the 40-day experiment, as much as 35% of a "1"3"7Cs-labelled particulate tracer deposited on the sediment surface was redistributed to depths of up to 11 cm by the polychaete. Three different reworking models were employed to model the profiles and quantify the biodiffusion and biotransport coefficients: a gallery-diffuser model, a continuous sub-surface egestion model and a biodiffusion model. Although the biodiffusion coefficients obtained for each model were quite similar, the continuous sub-surface egestion model provided the best fit to the data. The average biodiffusion coefficient, at 1.8 #+-# 0.9 cm"2 y"-"1, is in good agreement with the values quoted by other workers on the bioturbation effects of this polychaete ...

Energy Technology Data Exchange (ETDEWEB)

A start safety apparatus of an engine adapted for a multipurpose power tool is described which consists of: an engine, an exciter coil generating alternate electromotive force in synchronism with rotation of the engine; an ignition coil having primary and secondary windings; a spark plug connected to the secondary winding of the ignition coil; a capacitor connected to the primary winding of the ignition coil the capacitor being charged with a positive half-cycle of the electromotive force; ignition timing control means for controlling discharge of the capacitor; a throttle control latch for setting a throttle valve of the engine in a predetermined throttle angle; a tool driven by the engine; and a centrifugal clutch transferring engine power to the tool when an engine speed exceeds a clutch-in speed.

Science.gov (United States)

familiarity fire triangle (i.e., fuel, oxidant, and ignition source) are excluded. It Is obvious that for the baseline safety goal for spacecraft this ...

Energy Technology Data Exchange (ETDEWEB)

Three-dimensional seismic wavefields may be extrapolated in depth, one frequency at a time, by two-dimensional convolution with a circularly symmetric, frequency- and velocity-dependent filter. This depth extrapolation, performed for each frequency independently, lies at the heart of 3-D finite-difference depth migration. The computational efficiency of 3-D depth migration depends directly on the efficiency of this depth extrapolation. McClellan transformations provide an efficient method for both designing and implementing two-dimensional digital filters that have a particular form of symmetry, such as the circularly symmetric depth extrapolation filters used in 3-D depth migration. Given the coefficients of one-dimensional, frequency- and velocity-dependent filters used to accomplish 2-D depth migration, McClellan ...

British Library Electronic Table of Contents (United Kingdom)

An assessment of the joint shear strength of exterior concrete beam-column joints reinforced internally with Glass Fibre Reinforced Polymer (GFRP) reinforcements under monotonically increasing load on beams keeping constant load on columns is carried out in this study. Totally eighteen numbers of specimens are cast and tested for different parametric conditions like beam longitudinal reinforcement ratio, concrete strength, column reinforcement ratio, joint aspect ratio and influence of the joint stirrups at the joint. Also finite element analysis is performed to simulate the behaviour of the beam-column joints under various parametric conditions. Based on this study, a modified design equation is proposed for assessing the joint shear strength of the GFRP reinforced beam-column specimens b...

Energy Technology Data Exchange (ETDEWEB)

Safety-technical factors related to spontaneous ignition and dust explosions of biomasses were investigated. Parametres of dust explosions and effect of inertisation on the maximum pressure (pmax) and the maximum rate of pressure rise (Kstmax) were studied at elevated initial pressure (1-9 bar). The level of inertisation required to prevent dust explosions totally was determined at different initial pressures. The sensitivity of fuels to spontaneous ignition and the effect of pressure on the sensitivity to and temperature of spontaneous ignition were studied on a pressurised dynamic self-ignition equipment. The effect of inertisation on the self-ignition temperature and alternatives of preventing spontaneous ignition by effective inertisation in the pressure ranges of 1 and 25 bar were investigated. As an example of application, results obtained with the ...

Energy Technology Data Exchange (ETDEWEB)

The gas composition of recent thermal waters is in perfect conformity with their geologic-tectonic positions. The composition of gas-liquid inclusions in the basic-hyperbasic xenoliths of basaltoid lavas depends on the depth from which xenoliths are supplied. (The depth is determined by using the methods of geological thermobarometers). By comparing available data the conclusion was drawn that the gas compositions of thermal waters reflect the depth of generation of deep fluid which heats them and depends on the penetration depth of the fluid-conducting fissure zones.

International Nuclear Information System (INIS)

... chemical radiation effects decomposition extraction columns gamma radiation

International Nuclear Information System (INIS)

... Union (INTAS), Brussels (Belgium) Science and Technology Center in Unkraine,

International Nuclear Information System (INIS)

Full text of publication follows: The hydrogen mitigation system of 20 igniters and 6 PARs is installed to control the hydrogen in the containment during severe accidents and design basis accidents, respectively, in Shin-Wolsung 1 and 2 nuclear power plants. The igniters are primarily installed at the hydrogen source locations, and the PARs are installed in the open spaces. The PARs will maintain the hydrogen concentration within the containment atmosphere below the limit of 4 v/o in accordance with Regulatory Guide 1.7 during design basis accidents. The igniters will maintain the hydrogen concentration within the containment atmosphere below the limit of 10 v/o in accordance with 10CFR50.34(f) during severe accidents. In addition, the PARs can be used as a supplementary means to control the hydrogen concentration during severe accidents because of their inherent passive characteristics. This paper shows the three ...

CERN Document Server

A simple analytical model of the barrier discharge in a long gap between opposing plane electrodes is developed. It is shown that the plasma density becomes uniform over large part of the gap in the course of the discharge development, so that one can speak of a formation of a dynamic positive column. The column completely controls the dynamics of the barrier discharge and determines such characteristics as the discharge current, discharge duration, light output, etc. Using the proposed model, all discharge parameters can be easily evaluated

British Library Electronic Table of Contents (United Kingdom)

An effective rehabilitation strategy is proposed to enhance the strength and stiffness of the beam-column joint in this study. An analytical model is proposed to predict the column shear of the joints strengthened with carbon fiber reinforced polymer (CFRP). Three full scale interior beam-column joints, including two specimens strengthened with CFRP and one prototype specimen, are tested in this study. The specimens are designed to represent the pre-seismic code design construction in which there is no transverse reinforcement. A new optical non-contact technique, digital image correlation (DIC), which can measure the full strain field of specimen, is used to measure and observe the full strain field of the joint. The experimental results show that the beam-column joints strengthened with ...

International Nuclear Information System (INIS)

Tests on the scrubbing column have led to the following results: Use of a scrubbing column with Raschig rings is only meaningful for the sedimentation of particles exceeding diameters of 0.5 #mu#m; drops of diameter size 1.5 #mu#m are formed in the column; more efficient drop precipitators in the column air flow ease the load on subsequent suspended material filters thereby contributing to a longer life of these filters even at higher sodium ion concentrations in the washing water; with distillate of an 8% rather than 0.8% salt solution a decontamination factor greater than 10 can be calculated since larger particles precipitate more readily. This only applies, however, under the condition that the washing water is renewed regularly, if necessary daily where higher aerosol concentrations are present. If not, the decontamination factor will be reduced through the salt-containing secondary aerosols from ...

Energy Technology Data Exchange (ETDEWEB)

Large scale experiments were performed to determine the effectiveness of thermal glow plug igniters to burn hydrogen in a condensing steam environment due to the presence of water sprays. The experiments were designed to determine if a detonation or accelerated flame could occur in a hydrogen-air-steam mixture which was initially nonflammable due to steam dilution but was rendered flammable by rapid steam condensation due to water sprays. Eleven Hydrogen Igniter Tests were conducted in the test vessel. The vessel was instrumented with pressure transducers, thermocouple rakes, gas grab sample bottles, hydrogen microsensors, and cameras. The vessel contained two prototypic engineered systems: (1) a deliberate hydrogen ignition system and (2) a water spray system. Experiments were conducted under conditions scaled to be nearly prototypic of those expected in Advanced Light Water Reactors (such as the Combustion Engineering ...

Energy Technology Data Exchange (ETDEWEB)

Atmospheric pressure tests were performed in which a palladium catalyst ignites and stabilizes the homogeneous combustion of methane. Palladium exhibited a reversible deactivation at temperatures above 750 C, which acted to ``self-regulate`` its operating temperature. A properly treated palladium catalyst could be employed to preheat a methane/air mixture to temperatures required for ignition of gaseous combustion (ca. 800 C) without itself being exposed to the mixture adiabatic flame temperature. The operating temperature of the palladium was found to be relatively insensitive to the methane fuel concentration or catalyst inlet temperature over a wide range of conditions. Thus, palladium is well suited for application in the ignition and stabilization of methane combustion.

Energy Technology Data Exchange (ETDEWEB)

In order to find the solution to the problem of depletion of conventional fuels and environmental pollution caused by them, new design concepts such as low heat rejection engines and alternate fuel vehicles have started to appear. The present study deals with the concept of alternate fuel vehicle using hydrogen as a fuel. Results of analytical study to minimize heat loss during the power stroke of a hydrogen fueled spark ignition engine have been presented. Effect of various design and operating parameters on heat losses using a simulation model developed by the authors have also been presented. The results shall be helpful in designing efficient hydrogen fuelled spark ignition engines. (orig.)

International Science & Technology Center (ISTC)

Highly Precision Method for Nondestructive Analysis of Surfaces in a Subnanometer Depth Range

Science.gov (United States)

Small metallic fragments can be trapped in combustible cartridge cases during manufacture and released into the interior-ballistic flow upon combustion of the case. Such particles may survive the interior-ballistic cycle and pose an ignition threat to the...

Energy Technology Data Exchange (ETDEWEB)

This book contains papers relating to the 1990 Future Transportation Technology Conference and Exposition. Included are the following papers; Examination of rich mixtures operation of a dual fuel engine, A hybrid natural gas vehicles, Performance analysis of a spark ignited engine with ETBE as a blending agent.

Energy Technology Data Exchange (ETDEWEB)

This patent describes in an dual gas-liquid fuel four cycle engine having cylinders and wherein each cylinder is operatively connected thereto and each cylinder has a piston, two inlet valves, two exhaust valves and a first liquid fuel injector. It comprises: at least one fuel torch cell operatively connected to at least one cylinder, the torch cell having a torch cell nozzle at one end thereof and the other end having appropriate means to connect the torch cell to a fuel supply, a second fuel injector mounted in the torch cell at a predetermined angle to an axis of the torch cell, the torch cell defining an auto-ignition chamber, the second fuel injector being in operative communication with the auto-ignition chamber by an injector nozzle passageway, the injector nozzle passageway entering the auto-ignition chamber at a predetermined angle relative to the axis, and a torch nozzle passage connecting the ...

Energy Technology Data Exchange (ETDEWEB)

A method and apparatus for operating a compression ignition engine having a cylinder wall, a piston, and a head defining a combustion chamber. The method and apparatus includes delivering fuel substantially uniformly into the combustion chamber, the fuel being dispersed throughout the combustion chamber and spaced from the cylinder wall, delivering an oxidant into the combustion chamber sufficient to support combustion at a first predetermined combustion duration, and delivering a diluent into the combustion chamber sufficient to change the first predetermined combustion duration to a second predetermined combustion duration different from the first predetermined combustion duration.

Energy Technology Data Exchange (ETDEWEB)

The paper considers the cyclic variations in performance parameters of a dual fuel engine fuelled with methane. It is shown that such an engine does display cyclic variations that are greater than the corresponding diesel operation, yet smaller than comparable spark ignition operation. The extent of cyclic variation in peak cylinder pressure and ignition delay increases, for any power output, as the pilot diesel quantity is reduced and the extent of gas substitution is increased. The use of extremely small pilots in the unmodified engine can lead to erratic engine performance. Greater cyclic variations are associated with low lead rather than high load operation.

Energy Technology Data Exchange (ETDEWEB)

By contrast to the large mass, complexity and recirculating power of conventional drivers for inertial confinement fusion (ICF), antiproton annihilation offers a specific energy of 90MJ/{micro}g and thus a unique form of energy packaging and delivery. In principle, antiproton drivers could provide a profound reduction in system mass for advanced space propulsion by ICF. We examine the physics underlying the use of antiprotons ({bar p}) to drive various classes of high-yield ICF targets by the methods of volumetric ignition, hotspot ignition and fast ignition. The useable fraction of annihilation deposition energy is determined for both {bar p}-driven ablative compression and {bar p}-driven fast ignition, in association with 0-D and 1-D target burn models. Thereby, we deduce scaling laws for the number of injected antiprotons required per capsule, together with timing and focal spot requirements. The ...

British Library Electronic Table of Contents (United Kingdom)

Abstract: [public affairs, ethical currents, Ireland, social research ethics] Liam Frink is contributing editor of Ethical Currents, the AN column of the AAA Committee on Ethics.

UK PubMed Central (United Kingdom)

A rapid and highly reproducible chromatographic technique has been developed for analysis and purification of complex mixtures of oligoribonucleotides. The method utilizes a column of microparticulate...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

In this work, chromatographic separation of niacin and niacinamide using pure water as the sole component in the mobile phase has been investigated. The separation and analysis of niacinamide have been optimized using three columns at different temperatures and various flow rates. Our results clearly demonstrate that separation and analysis of niacinamide from skincare products can be achieved using pure water as the eluent at 60^oC on a Waters XTerra MS C18 column, a Waters XBridge C18 column, or at 80^oC on a Hamilton PRP-1 column. The separation efficiency, quantification quality, and analysis time of this new method are at least comparable with those of the traditional HPLC methods. Compared with traditional HPLC, the major advantage of this newly developed green chromatography techniq...

British Library Electronic Table of Contents (United Kingdom)

Abstract A novel and convenient protocol for the preparation of an open-tubular column coated with chitosan-silica hybrid using chitosan and silane-coupling agent (-glycidoxy-propyltrimethoxysilane) was developed for CEC, in which, chitosan was covalently bonded to the inner wall of a fused-silica capillary using -glycidoxy-propyltrimethoxysilane as a cross-linking agent. The stationary phase was hydrophilic due to the chitosan-silica hybrid with abundant amine and hydroxyl functional groups. The chromatographic characteristics of the column were evaluated by the separation of some organic acids and inorganic anions. The column showed good selectivity for nucleotides, aromatic acids, and inorganic anions. The mechanism for the separation of these compounds was primarily based on the hydrop...

Science.gov (United States)

... applications related to military and intelligence area ... the technology solved yet, but the open issue still ... fields, columns; ie data source, document type ...

Energy Technology Data Exchange (ETDEWEB)

Using the example of perhydrophenanthrene, perhydroanthracene and cyclopentanodecalin isomers a possibility is shown to use packed capillary columns containing graphitized thermal carbon black for a complete separation of high-boiling mixtures of polycyclic saturated hydrocarbon isomers in accordance with the geometric structure of their molecules.

International Nuclear Information System (INIS)

Following a recent refurbishment of the NPL Thermal Neutron Facility, the spectrum of the epithermal and fast neutron component of the beam produced by the thermal column of this facility was measured over the energy range from thermal to 20 MeV using a Bonner sphere spectrometry system. The effect of the presence of epithermal and fast neutrons on the measured response of commonly-used thermal neutron dosemeters was calculated. (author)

Energy Technology Data Exchange (ETDEWEB)

The purpose of this research was to investigate the de-entrainment of boron for evaporators used in nuclear power plants. The forced circulation and semi-continuous type evaporator was used in the experiment. Cyclone and glass-wool packed column which is supposed to provide good decontamination factor as well as easy maintenance, were selected as de-entrainment device to be used in the evaporation of radioactive liquid wastes. The de-entrainment device combined with cyclone and glass-wool column has shown overall DF more than 1000 for boron.

Energy Technology Data Exchange (ETDEWEB)

In order to judge the potential fluorescent lamp applications of various low-pressure positive column discharges it is necessary to measure the absolute power emitted in the ultraviolet region of the spectrum. For rare-gas discharges the principle emission occurs in the vacuum ultraviolet so that it is difficult to measure the radiant emittance (power per unit area) of the resonance radiation by standard methods. Two independent techniques are discussed for measuring the radiant emittance of positive column discharges in the vacuum ultraviolet. These techniques are used to study xenon positive column discharges at the resonance wavelength of 147 nm. The first method relies on the measurement of the resonance level density by absorption techniques. The effective decay rate of the resonance level is then determined by the simulation of resonance radiation transport. These two quantities are combined to yield the radiant ...

International Nuclear Information System (INIS)

The "6"2Zn-"6"2Cu generator system is one of the few which yield a pure positron emitting daughter. The authors have developed a method for the preparation of this generator system following 32 MeV #alpha# particle bombardment of nickel targets. The chemical processing involves two stages: first a hydrous zirconium oxide column is used at pH 4-5 to separate the zinc and copper activities produced in the target nickel, and secondly, a conventional anion exchange column is used to retain the "6"2Zn and remove all copper activities in 2M HCl. This column serves as the "6"2Cu generator which will yield pure "6"2Cu repeatedly, free from "6"2Zn and other impurities, in a mixture of HCl and NaCl. A method is outlined also to obtain a solution of "6"2Zn using the hydrous zirconium oxide (HZO) column. "6"1Cu can be prepared as a by-product in the above procedure, but a method for the preparation of "6"1Cu alone ...

Energy Technology Data Exchange (ETDEWEB)

In this paper, an amount of confining reinforcement required for the sufficient flexural ductility of reinforced concrete column was investigated. An equation to calculate the required confining reinforcement ratio was deduced from the analytical investigation and examination on the previous experimental data as to the effects of various factors on the required confining reinforcement ratio. The rotation angle required in plastic hinges, the axial force ratio, the material properties such as concrete strength, and the ratio of core area to the whole area of column sections were employed as the factors. From the examination of the equation, it was shown that the ultimate rotation in plastic hinges calculated by the equation was more conservative than the ultimate rotaion angle of members obtained by test column specimens. It was also indicated that the ultimate rotation angle of members of columns failed ...

International Nuclear Information System (INIS)

The penetration depth and concentration distribution for vanadium ions with low energy implanted into the dry peanut seeds is determined by scanning electron microscope and X-ray energy dispersion spectrometer. The results show that the depth-concentration distribution is a Gaussian distribution with a long tail and the maximum penetration depth is about 13.6 #mu#m for V"+ with 200 keV in cotyledon of the peanut. The experimental result of the implanted V"+ range in the peanut seeds is compared with the calculating value of the TRIM95

Science.gov (United States)

... HARDENED CUP AND CARBURIZED AND HARDENED CORES HAVE BEEN PROFILED USING 2 TYPES OF EDDY CURRENT PROBES. ...

Energy Technology Data Exchange (ETDEWEB)

A mathematical model was developed to simulate the combustion process of a direct injection diesel engine. The model considers the key features of such a combustion process; namely fuel droplet evaporation, spray formation, mixing, ignition of heterogeneous burning of the fuel. To model mixing, great emphasis was placed on treating both large and small scale aspects of mixing, the model divides the combustion chamber into three distinct regions of air, fuel spray, and a turbulent plume that is formed once ignition occurs. The fuel spray itself is considered to be composed of multiple zones, which in turn are made of cells of equal mass and of different thermodynamic states. Micromixing of the fuel and air cells, within each zone of the jet and the turbulent plume, is then achieved by utilizing the concept of Monte Carlo stochastic coalescence dispersion technique. The frequency of such cell interactions within each zone is obtained by employing ...

Energy Technology Data Exchange (ETDEWEB)

The report details the results of a series of large-scale experiments where small coal fires were used to ignite conveyor belting at air velocities ranging from 0.76 m/s to 6.1 m/s. In the tests, electrical strip heaters imbedded within a pile of coal were used to heat the coal to a point of flaming ignition. The flaming coal subsequently ignited conveyor belting located approximately 5 to 10 cm above the coal pile. During the tests, temperature, CO, and smoke levels were continuously measured in order to determine both alarm time and level as the fire intensity progressed through the stages of smoldering coal, flame coal, and flaming coal plus flaming belt. Analysis of the data leads to certain conditions of air velocity and sensor alarm levels that are required for early detection of conveyor belt entry fires. Two nomographs are presented which define sensor alarm levels and sensor spacings as a function of belt entry ...

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A natural gas and diesel dual-fuel turbocharged compression ignition (CI) engine is developed to reduce emissions of a heavy-duty diesel engine. The compressed natural gas (CNG) pressure regulator is specially designed to feed back the boost pressure to simplify the fuel metering system. The natural gas bypass improves the engine response to acceleration. The modes of diesel injection are set according to the engine operating conditions. The application of honeycomb mixers changes the flowrate shape of natural gas and reduces hydrocarbon (HC) emission under low-load and lowspeed conditions. The cylinder pressures of a CI engine fuelled with diesel and dual fuel are analysed. The introduction of natural gas makes the ignition delay change with engine load. Under the same operating conditions, the emissions of smoke and NO{sub x} from the dual-fuel engine are both reduced. The HC and CO emissions for the dual-fuel engine remain within the range ...

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The feasibility of using hydrogen as the sole fuel in a direct injection diesel engine was investigated. An air cooled single cylinder Lister ST1 diesel engine was modified to operate as a low-heat-rejection engine for this study. Partially stabilized zirconia ceramic parts were used to shield the combustion space of the engine. Using a compression ratio of 17.9:1 and motoring the test engine at 21000 rpm, a maximum compression temperature of approximately 900 K was achieved. Under these operating conditions, all lubricants tested were found to burn. Lowering the speed to 1450 rpm and the compression ratio to 17.1, lubricant combustion and hot spots were successfully eliminated. The maximum compression temperature, when compression ignition of hydrogen was tried, was in the 800 K range. The corresponding ceramic surface temperature was estimated to reach 600-700 K. Only sporadic compression ignition of hydrogen was achievable. (author).

British Library Electronic Table of Contents (United Kingdom)

The ever increasing fossil fuel usage and cost, environmental concern has forced the world to look for alternatives. Straight vegetable oils in compression ignition engine are a ready solution available, however, with certain limitations and with some advantages as reported by many researchers. A comprehensive and critical review is presented specifically pertaining to straight vegetable oils usage in diesel engine. A detailed record of historical events described. Research carried out specifically under Indian conditions and international research work on the usage of straight vegetable oils in the diesel engine is separately reviewed. Many researchers have reported that straight vegetable oils in small percentage blends with diesel when used lower capacity diesel engines have shown great...

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From 1965 to 1980 ash content in anthracite from the Donbass supplied to power plants increased from 21.9 to 35.5%, moisture content increased from 7.6 to 10.1%, calorific value declined from 23.7 to 18.5 MJ/kg. Combustion of anthracite culm is stabilized by mazout combustion. Heat treatment of anthracite culm by means of plasma generators improves fuel quality. High temperature causes emission of volatile matter from anthracite and partial gasification of coke particles. Combustion of volatile matter from anthracite and coke is a reliable ignition method for anthracite culm. It also stabilizes combustion of pulverized anthracite. Heat treatment of about 20% anthracite by plasma generators reduces nitrogen oxide emission from a furnace by 30-40%. 5 refs.

British Library Electronic Table of Contents (United Kingdom)

LLNL is developing the nuclear fusion based Laser Inertial Fusion Energy (LIFE) power plant concept. The baseline design uses a depleted uranium (DU) fission fuel blanket with a flowing molten salt coolant (flibe) that also breeds the tritium needed to sustain the fusion energy source. Indirect drive targets, similar to those that will be demonstrated on the National Ignition Facility (NIF), are ignited at 13Hz providing a 500MW fusion source. The DU is in the form of a uranium oxycarbide kernel in modified TRISO-like fuel particles distributed in a carbon matrix forming 2-cm-diameter pebbles. The thermal power is held at 2000MW by continuously varying the 6Li enrichment in the coolants. There are many options to be considered in the engine design including target yield, U-to-C ratio in th...

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Multi-kilo-electron-volt x-ray microscopy will be an important laser-produced plasma diagnostic at future megajoule facilities such as the National Ignition Facility (NIF). However, laser energies and plasma characteristics imply that x-ray microscopy will be more challenging at NIF than at existing facilities. We use analytical estimates and numerical ray tracing to investigate several instrumentation options in detail, and we conclude that near-normal-incidence single spherical or toroidal crystals may offer the best general solution for high-energy x-ray microscopy at NIF and similar large facilities. Apertured Kirkpatrick{endash}Baez microscopes using multilayer mirrors may also be good options, particularly for applications requiring one-dimensional imaging over narrow fields of view. {copyright} 1998 Optical Society of America

British Library Electronic Table of Contents (United Kingdom)

A detailed chemical kinetic reaction mechanism is developed for primary reference fuel mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethyl nonane for diesel cetane ratings. The mechanisms are constructed using existing rules for reaction pathways and rate expressions developed previously for the primary reference fuels for gasoline octane ratings, n-heptane and iso-octane. These reaction mechanisms are validated by comparisons between computed and experimental results for shock tube ignition and for oxidation under jet-stirred reactor conditions. The combined kinetic reaction mechanism contains the submechanisms for the primary reference fuels for diesel cetane ratings and submechanisms for the primary reference fuels for gasoline octane ratings, all in one integrated large kinetic reac...

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Single-particle combustion of coal char is analyzed using a generalized shrinking core model. Finite volume method, which was earlier employed by the authors in solving moving boundary problems involving fluid-solid noncatalytic reactions in general, is used to solve fully transient mass and energy equations. The model takes into account convection and diffusion inside the particle as well as in the boundary layer. The computed results are compared with the experimental data of the authors for combustion of coal char in a fluidized bed combustor. The effects of parameters such as bulk temperature and initial particle radius on the combustion dynamics are examined. The phenomena of ignition and extinction are also investigated. Finally, the importance of Stefan flow, originating due to nonequimolar counterdiffusion, on combustion of coal char is analyzed.

International Nuclear Information System (INIS)

Nitric acid leaching from the weak base anion (WBA) exchanger had been evaluated and based on this a 5% mixture of nitric acid loaded weak base anion exchanger with fresh weak base anion exchanger (NLWBA) at the bottom of the ion exchange column has been devised to maintain an outlet pH in the range of 5.0 to 5.5 during Gd removal from the moderator system of TAPP - 3 and 4. A three layered bed had been constituted wherein strong acid cation (SAC) exchanger is placed as the top layer while a mixed bed of SAC and WBA or pure WBA is used as the middle layer and the 5% NLWBA was used as the bottom most layer. This bed configuration would result in an iso-pH regime in the moderator system during the Gd removal along with quantitative removal of Gd. Two three-layer bed columns were prepared at TAPS - 3 and 4 in July 07. The resin was loaded in batches and after preparing the column, the column was deuterated ...

International Nuclear Information System (INIS)

A deep band of #left brace#311#right brace# defects was created 520 nm below the silicon surface with a 350 keV Si implant followed by a cluster-forming rapid thermal anneal (800 C, 1000 s). Chemical etching was used to vary the depth to the surface of the #left brace#311#right brace#-defect band. Afterwards, the defect dissolution was investigated at 750 C for different times. Varying the depth in this fashion assures that only the depth and no other feature of the cluster distribution is changed. The #left brace#311#right brace# defects were analyzed by plan-view, transmission electron microscopy. We show that the dissolution time of the #left brace#311#right brace#-defect band varies linearly with depth, confirming that surface recombination controls the dissolution and is consistent with analogous observations of transient enhanced diffusion.

International Nuclear Information System (INIS)

A method, based on anion exchange chromatography, is presented for the isolation of "1"3"9Ce after production by a proton-induced nuclear reaction on a thick praseodymium target. After bombardment the target is dissolved in nitric acid and "1"3"9Ce oxidised to the Ce(IV) oxidation state with bromic acid. "1"3"9Ce is then separated form the praseodymium by anion exchange chromatography on a Ag MP-1 resin column in a nitric acid - bromic acid mixture. "1"3"9Ce is sorbed onto the resin column and praseodymium eluted with the acid mixture. The bromic acid is washed out of the column with nitric acid and "1"3"9Ce finally eluted with dilute nitric acid containing sulphur dioxide.

British Library Electronic Table of Contents (United Kingdom)

The paper discusses the aspects of repair and retrofitting technique adopted for a damaged reinforced concrete beam-column joint specimen under cyclic loading. A specimen designed based on Indian Standard specifications with consideration of seismic load but without adopting ductile detailing (NonDuctile) was investigated under reverse cyclic loading. Then, the damaged nonductile specimen was repaired with epoxy mortar and grouted using low viscous polymer, and retrofitted using fiber reinforced plastic (FRP) wrapping in beam and column components and steel plate jacketing in joint region. The experimental results showed that the retrofitted specimen not only regained its original strength and stiffness but also has overcome the deficiencies of nonductile detailing. The present study shows...

British Library Electronic Table of Contents (United Kingdom)

We have studied the nature of continuum emitted in the visible spectral range from a noncontracted positive column of discharge in a cesium vapor-xenon mixture at a pressure of 45 Torr and at a degree of ionization below 3 ? 10?6. The main contribution to the continuous emission under such conditions is due to electron-xenon atom bremsstrahlung. The intensity of emission has been experimentally and theoretically studied as a function of the electric field strength and electron density in the positive column. It is established that an increase in the visible emission intensity with the electric field strength is related to an increase in the number of hot electrons in plasma.

British Library Electronic Table of Contents (United Kingdom)

Glass fiber-reinforced polymer (GFRP) reinforcing bars were used recently as main reinforcement for concrete structures. The noncorrodible GFRP material exhibits linear-elastic stress-strain characteristics up to failure with relatively low modulus of elasticity compared to steel. This raises concerns on GFRP performance in structures where energy dissipation, through plastic behavior, is required. The objective of this research project is to assess the seismic behavior of concrete beam-column joints reinforced with GFRP bars and stirrups. Two full-scale exterior T-shaped beam-column joint prototypes are constructed and tested under simulated seismic load conditions. One prototype is totally reinforced with GFRP bars and stirrups, while the other one is reinforced with steel. The experimen...

British Library Electronic Table of Contents (United Kingdom)

Abstract Remediation of ground water containing anionic contaminants presents a great challenge. Because of its low cost, surfactant-modified zeolite (SMZ) has been studied for >10 years for potential uses as permeable barrier materials to remove anionic contaminants from water. In this study, zeolite aggregates with particle size of 3.4 to 4.8 mm were modified by hexadecyltrimethylammonium (HDTMA) bromide, a cationic surfactant, to a surfactant loading level of 80 mmol/kg and a concurrent counterion bromide loading level of 34 mmol/kg. While no retardation of chromate transport was observed for unmodified columns, a retardation factor of 60 was found for chromate transport through the SMZ columns. Slow but persistent desorption of HDTMA occurred throughout the chromate transport experimen...

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A C{sub 60} {sup +} primary ion source has been coupled to an ion microscope secondary ion mass spectrometry (SIMS) instrument to examine sputtering of silicon with an emphasis on possible application of C{sub 60} {sup +} depth profiling for high depth resolution SIMS analysis of silicon semiconductor materials. Unexpectedly, C{sub 60} {sup +} SIMS depth profiling of silicon was found to be complicated by the deposition of an amorphous carbon layer which buries the silicon substrate. Sputtering of the silicon was observed only at the highest accessible beam energies (14.5 keV impact) or by using oxygen backfilling. C{sub 60} {sup +} SIMS depth profiling of As delta-doped test samples at 14.5 keV demonstrated a substantial (factor of 5) degradation in depth resolution compared to Cs{sup +} SIMS depth profiling. This degradation is thought to result from the ...

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The development and evaluation of a post-column reaction detector sensitive to platinum(II) complexes is presented in which sodium bisulfite is used as the derivatizing agent with potassium dichromate as an activating agent. The influences of mobile phase changes (i.e., pH, organic modifiers, electrolytes), oxygen, metal ions, and order of reagent addition on reaction kinetics and product yield are defined and used in optimization of detector response. Detection at lambda/sub max/ 290 nm results in an on-line post-column sensitivity of 40-60 ng/mL for selected cis-dichloroplatinum complexes and a sensitivity of 300-1200 ng/mL for four (substituted)-malonato-platinum complexes. The reaction detector is used to monitor the kinetics of aquation of cisplatin (CDDP) and to quantitate CDDP degradation in plasma. As the sensitivity for CDDP in plasma is comparable to that achieved from high pressure liquid chromatography (HPLC) effluent ...

UK PubMed Central (United Kingdom)

Proprioceptive sensory signals inform the CNS of the consequences of motor acts, but effective motor planning involves internal neural systems capable of anticipating actual sensory feedback....Full Text Available

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Cross section parameterizations for antiproton production in pp collisions are used to predict the antiproton/proton ratio resulting from a flux of cosmic protons with energy spectral index of 2.6 interacting with a 5 gm/cm/sup 2/ column density of H. (GHT)

Science.gov (United States)

The report gives results of an examination, including mutagenic screening, of the chemical composition of residual fuel oils and their column chromatography pre-fractions. A degree of correlation between composition and mutagenicity has been achieved. Radionuclide data has been o...

UK PubMed Central (United Kingdom)

Neocortical columns are functional and morphological units whose architecture may have been under selective evolutionary pressure in different mammalian lineages in response to encephalization and specializations...Full Text Available

Science.gov (United States)

RISI SQ-80 ignitor is a thermite filled exploding bridgewire ignitor. Eleven shots were fired. Film development time was the major time problem. Other problems also existed. These EBW ignitors should enhance safety in igniting rocket propellant. 11 figs.

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During the first 18 months of this project, four experimental subtasks were to have begun but only one of these was to have been completed. Additionally, five modeling subtasks were scheduled to begin, four of which were to have been completed. We are on schedule for all but one of these subtasks. All four experimental tasks are progressing on schedule. Initial durability tests were completed. The conclusions drawn from this first round of durability tests are being used to design the next set of tests. Initial baseline engine data were acquired and showed that the engine selected for this task behaves as hoped. However, the dyno controller is inadequate. The engine will be moved to another dyno during the near future. The modeling tasks are also progressing well. A model for the dynamic response of the ignition circuit was developed and validated. Two technical papers resulting from this model were submitted for publication. Development of a model for the railplug ...

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An experimental study was performed to provide the combustion and emission characteristics resulting from fuel-reactivity controlled compression ignition (RCCI) combustion mode utilizing dual-fuel approach in a light-duty, multi-cylinder diesel engine. In-cylinder fuel blending using port fuel injection of gasoline before intake valve opening (IVO) and early-cycle, direct injection of diesel fuel was used as the charge preparation and fuel blending strategy. In order to achieve the desired auto-ignition quality through the stratification of the fuel-air equivalence ratio ( ), blends of commercially available gasoline and diesel fuel were used. Engine experiments were performed at an engine speed of 2300rpm and an engine load of 4.3bar brake mean effective pressure (BMEP). It was found that significant reduction in both nitrogen oxide (NOx) and particulate matter (PM) was realized successfully through the RCCI combustion mode even without ...

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Spark ignition internal combustion engines perform satisfactorily when the fueled with biomass producer gas from a fluidized bed gasifier. Although power output is reduced compared to natural gas levels, full power recovery can be achieved with a relatively low level of supercharging. Important considerations are an adequate fuel delivery system and adquate gas cleaning. ref.

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The isotopic enrichment of copper ions in a positive column Cu-Nu discharge using optogalvanic excitation is analyzed with a rate equation model With excitation at 510.6 nm, the fraction of the ions belonging to the 63-amu isotope of copper is enriched relative to the neutral abundance. Enrichment as large as 10% is calculated when the initial abundance of the neutral isotope is small (< or =0.1) and the discharge current density is large (> or =75 mA/cm/sup 2/). The degree of enrichment is examined as a function of the initial abundance, discharge current, the rate of charge exchange, and the diameter of the discharge tube.

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Optimal neutron energy for boron neutron capture therapy (BNCT) has been studied. Epithermal neutron is superior to thermal neutrons in treating deep-seated tumors. Design of the epithermal neutron column for BNCT has been performed by using a two-dimensional transport calculation code. Aluminum and heavy water are used as moderation materials. A thermal neutron column is also designed using heavy water as thermalization material. The configuration of the facility for treatment and research of BNCT and also for basic radio-biological studies of neutrons has been presented.

British Library Electronic Table of Contents (United Kingdom)

The humidification?dehumidification process is an interesting technique that has been adapted for water desalination. Previous works experimentally investigated desalination processes in the shell and tube columns, where the humidification and dehumidification were thermally coupled and simultaneously performed at the tube and shell sides, respectively. In this work, a comprehensive steady-state mathematical model was developed for such a humidification?dehumidification desalination process by taking into account the heat and mass balances on both sides of the desalting column, the mass transfer rate at the humidification side, and the heat transfer rate between the dehumidification side and humidification side. Meanwhile, the mass transfer coefficient at the humidification side and the to...

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The use of aqueous methyldiethanolamine (MDEA) for selective removal of hydrogen sulfide from acid gas streams has been studied in a 2 inch column packed with 1/4 inch ceramic Intalox saddles. The column was operated in a counter-current, steady state fashion. The feed gas composition varied between 1 and 5 mole % hydrogen sulfide and between 0 and 50 mole % carbon dioxide. In order to assist the development of packed column absorption models, the rate at which pure carbon dioxide absorbs into 2 M MDEA was measured as a function of pressure, liquid flow rate and packed bed length. The importance of end effects was carefully evaluated. In addition, draining and tracer methods were used to estimate the amount of static holdup present in the column. Using classical draining methods, as much as 50 % of the total holdup was found to be static. However, according to the step decrease in tracer method, less ...

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Soil dressing on coal ash reclaimed land is a covering to use the land for agriculture. This study was carried out to find out the necessary depth of soil covering the ash layer in order to have normal crop growth. Two kinds of crops, Japanese radish, and rakkyo were planted in cover soil on the fly ash packed in wooden boxe (90 cm x 90 cm x 90 cm). Depths of cover soil were 20 cm, 30 cm, 40 cm and 50 cm. The results were summarized as follows: growth and yield of Japanese radish and rakkyo were increased with increasing depth of cover soil; root development of Japanese radish was inhibited at the lower coal ash layer. Main root length and edible root length of Japanese radish were decreased with decreasing depth of cover soil; boron and molybdenum contents in the plants remarkably increased with decreasing depth of cover soil. This may be due to the absorption of these elements ...

Science.gov (United States)

depth timber industry experience with state-of-the-art ... difficult to find high-value pockets of timber (also known as timber stands ) to supply his ...

Science.gov (United States)

The fields in this dataset are: Date Lake Depth Dissolved Organic Carbon Dissolved carbohydrates and amino acids Inorganic Nutrient Concentrations Primary ...

Science.gov (United States)

The extraction and recovery of cesium from simulated Purex waste solutions was successfully demonstrated in the pilot plant pulse column. Stable volumetric capacities as high as 670 gph/ft/sup 2/ (sum of both phases) were obtained for alkaline supernate-type waste; however, for efficient operation (transfer unit height - HTU -of two feet or less), the maximum throughput rate was limited to about 500 gph/ft/sup 2/. This rate could be achieved with feeds diluted to densities within 0.08 g/cc of the solvent density. Stable feed was prepared from simulated current, denitrated waste by addition of citric acid to complex the iron before neutralization to the desired operating pH of 7 to 8. Capacities of 500 gph/ft/sup 2/ were readily achieved with this feed, together with HTU's of 1.0 to 1.3 feet. Sodium extracted with the cesium was satisfactorily scrubbed from the solvent with a dilute citric acid solution. Scrub section sodium ...

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It is carried out a calculation to determine the energy spectra of secondary {sup 3}He at small atmospheric depths. It is produced in the spallation reaction of primary helium and heavier nuclei in the overlying atmosphere. It is examined the effect of the geomagnetic cut-off on the spectral shape of the secondary {sup 3}He nuclei. The calculations are being carried out for both solar minimum and maximum periods. Results from these calculations will be presented at the Conference.

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The possibilities and problems of PCA in phase separation are shown on Ni, Pd, and Pt silicides. The PCA depth profiles are less influenced by sputter and matrix effects than usual Auger depth profiles. The position of the silicide-Si interface is well defined by the component distribution crossover in PCA profiles. An interface component between Pd and Pt silicides and Si substrate is determined by PCA.

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The method of production of xAl{sub 2}O{sub 3}-yTiO{sub 2} compositions provides for the depth distribution of coating components and specifies its mechanical properties. In case of the composition obtained by cladding, titanium is mainly concentrated at the substrate. In case of mechanical mixture or composition obtained by sintering the oxides, the depth distribution of coating components is random.

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Most algorithms for three-dimensional (3D) reconstruction from electron micrographs assume that images correspond to projections of the 3D structure. This approximation limits the attainable resolution of the reconstruction when the dimensions of the structure exceed the depth of field of the microscope. We have developed two methods to calculate a reconstruction that corrects for the depth of field. Either method applied to synthetic data representing a large virus yields a higher resolution reconstruction than a method lacking this correction.

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Depth dose distributions for protons in the energy range from 2 to 600 MeV have been calculated by Monte Carlo and analytical methods. The dependence on energy of Maximum Dose Equivalent (MDE), quality factor and isotropic factor recommended for practical use are presented. The problems connected with regulation of maximum permissible proton fluxes are discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

The use of deuterium-tritium fuel in the Compact Ignition Tokamak will require applying remote handling technology for ex-vessel maintenance and replacement of machine components. Highly activated and contaminated components of the fusion devices auxiliary systems, such as diagnostics and RF heating, must be replaced using remotely operated maintenance equipment in the test cell. In-vessel remote maintenance included replacement of divertor and first wall hardware, faraday shields, and for an in-vessel inspection system. Provision for remote replacement of a vacuum vessel sector, toroidal field coil or poloidal field ring coil was not included in the project baseline. As a result of recent coil failures experienced at a number of facilities, the CIT project decided to reconsider the question of remote recovery from a coil failure and, in January of 1990, initiated a coil replacement study. This study focused on the technical requirements and impact on fusion ...

International Nuclear Information System (INIS)

LLNL is developing the nuclear fusion based Laser Inertial Fusion Energy (LIFE) power plant concept. The baseline design uses a depleted uranium (DU) fission fuel blanket with a flowing molten salt coolant (flibe) that also breeds the tritium needed to sustain the fusion energy source. Indirect drive targets, similar to those that will be demonstrated on the National Ignition Facility (NIF), are ignited at #approx#13 Hz providing a 500 MW fusion source. The DU is in the form of a uranium oxycarbide kernel in modified TRISO-like fuel particles distributed in a carbon matrix forming 2-cm-diameter pebbles. The thermal power is held at 2000 MW by continuously varying the "6Li enrichment in the coolants. There are many options to be considered in the engine design including target yield, U-to-C ratio in the fuel, fission blanket thickness, etc. Here we report results of design variations and compare them in terms of various figures of merit such as ...

Energy Technology Data Exchange (ETDEWEB)

This guide explained the requirements for Off-Road Compression Ignition Engine Emission Regulations established under the Canadian Environmental Protection Act. The regulations are enforced by Environment Canada, which authorizes and monitors the use of the national emissions mark. The regulations prescribe standards for off-road engines that operate as reciprocating, internal combustion engines, other than those that operate under characteristics similar to the Otto combustion cycle and that use a spark plug or other sparking device. The regulations apply to engines that are typically diesel-fuelled and found in construction, mining, farming and forestry machines such as tractors, excavators and log skidders. Four different types of persons are potentially affected by the regulations: Canadian engine manufacturers; distributors of Canadian engines or machines containing Canadian engines; importers of engines or machines for the purpose of sale; and persons not in ...

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The fuel-injection system of the Niigata 6L 16X-AG dual-fuel engine is structured to steadily supply injected fuel during diesel-engine operation, and to distribute oil at a low rate to all the cylinders during gas-engine operation. The dual-fuel engine is started by the diesel engine operation and is changed over to gas-engine operation when the load increases. This change over is done automatically with a link mechanism. Regarding the gas-supply system, the changing pressure of supply gas is controlled by a pressure control valve which is stable and most adequate for the engine. The dual-fuel engine has the following features: (1) a high compression ratio is adopted, which reduces fuel consumption and thermal efficiently; (2) if the supply of gas decreases or stops, while continuing loaded operations, it can immediately shift to diesel engine operation automatically and continue the operation; (3) ignition is done by the injection of pilot oil, thus eliminating ...

Energy Technology Data Exchange (ETDEWEB)

This report describes results from emissions testing of a prototype diesel engine, developed by Volvo Truck Corporation of Sweden, which uses pilot injection of diesel fuel for compression ignition of alcohol fuel injection for main combustion. In addition to this dual-fuel engine, emission testing was also conducted on a heavy-duty diesel engine of similar design. Both engines were tested over the 1979 13-mode FTP, or shorter versions of this modal test, and over the 1984 Transient FTP as well as an experimental bus cycle. The dual-fuel engine was characterized with methanol, ethanol and ethanol with 30 percent water (wt %). An oxidation catalyst was also used with methanol and ethanol. Emission characterization included regulated emissions (HC, CO, and NOX) along with total particulate, unburned alcohols, individual hydrocarbons, aldehydes, phenols, and odor. The particulate matter was characterized in terms of particle size distribution, sulfate content, C, H, ...

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The effects of compression ratio on the history of the fuel-burning process was investigated in a single-cylinder direct-injection diesel engine. Two compression ratios of 21.4 and 18.5 were studied by using two wide and shallow bowls. The engine was operated at different speeds and overall air-fuel ratios, but with constant start-of-combustion timing at top dead center. The measured cylinder pressure was used to derive fuel-burning rate. At all conditions, the low-compression-ratio bowl had a larger mass of premixed-burned fuel and a higher peak specific fuel-burning rate. The fuel-burning rate in the diffusion-controlled phase of combustion decreased with decreasing compression ratio. The resulting combustion duration became longer at reduced compression ratio, and the difference could be as large as 14 crank-angle degrees. For the engine conditions examined in this study, the mass of fuel present in the combustion chamber at ignition appears to be the dominant ...

Energy Technology Data Exchange (ETDEWEB)

NO[sub x] emission legislation requirements for large-bore internal combustion engines have required engine manufacturers to continue to develop and improve techniques for exhaust emission reduction. This paper describes the development of the Cooper-Bessemer Clean Burn gas-diesel (dual-fuel) engine that results in NO[sub x] reductions of up to 92 percent as compared with an uncontrolled gas-diesel engine. Historically, the gas-diesel and diesel engine combustion systems have not responded to similar techniques of NO[sub x] reduction that have been successful on straight spark-ignited natural gas burning engines. NO[sub x] levels of a nominal 1.0 g/BHP-h, equal to the spark-ignited natural gas fueled engine, have been achieved for the gas-diesel and are described. In addition, the higher opacity exhaust plume characteristic of gas-diesel combustion is significantly reduced or eliminated. This achievement is considered to be a major ...

Energy Technology Data Exchange (ETDEWEB)

The necessary conditions to design the methanol-fueled direct injection diesel engine with a reservoir type glow plug were cleared up from the points of view to prevent the air contamination and to use as an alternative oil for automotives, and as a result the good engine performance and emission characteristics could be obtained under the wide operating condition. The following facts were clarified: It is necessary to arrange the glow plug on the line of atomizing axis near the nozzle hole to ensure the ignitability under a wide operating condition. The reservoir type glow plug which reserves the premixed gas around the glow plug can shorten the ignition delay time and improve the combustion stability and the net thermal efficiency in the light load region. The combustion in the light load region was accelerated, NO{sub x} emission rate was suppressed and moreover, the net thermal efficiency and catalyst conversion rate were improved by ...

Energy Technology Data Exchange (ETDEWEB)

Solid polymer fuel cell (SPFC) systems are compared to spark ignition (SI) engine power systems for utility vehicle applications. Utility vehicles provide crew and payload transport and electrical power at work sites lacking grid supply. The methodology emphasizes comparison on an equal service basis. Using power system component models and numerical analysis, power systems are designed using SI engine and SPFC technologies. The power systems are compared on the basis of fuel energy consumed and life cycle cost (LCC). Gasoline is the fuel for the SI engines, while liquid hydrogen is used for the SPFC. Three types of SPFC power system configurations are studied. The superior SPFC in terms of LCC is a fuel cell/battery hybrid where the fuel cell is sized to provide average driving power. Using today's technology, SPFC power systems have a lower fuel consumption but have higher capital costs and consequently lose to SI engine power systems with regard to LCC. ...

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Pile foundations in several coastal and offshore structures are subjected to significant amounts of lateral loads due to wave action. Usually batter piles are adopted to resist large lateral loads. In this investigation an attempt has been made to study the behavior of batter pile in clayey soils through an experimental program carried out on instrumented model aluminium piles of 26 mm diameter in a test tank of size, 1,200 mm x 800mm x 1,100 mm. The pile was instrumented with electrical resistance type strain gauges to determine the bending moment variations along the depth of embedment of pile. Bending moment vis depth relationships were used to determine the Soil reaction (p) and lateral displacement (y) along the length of the pile for the applied load. From the bending moment vs depth curves it is found that depth of maximum bending moment is greater for negative batter pile than for vertical and ...

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We have investigated tailoring damage effects of explosive devices by addition of unconventional materials, specifically combustible metals. Initial small-scale as well as full-scale testing has been performed. The explosives functioned to disperse and ignite these materials. Incendiary, enhanced-blast, and fragment-damage effect have been identified. These types of effects can be used to extend the damage done to hardened facilities. In other cases it is desirable to disable the target with minimal collateral damage. Use of unconventional materials allows the capability to tailor the damage and effects of explosive devices for these and other applications. Current work includes testing of an incendiary warhead for a penetrator.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a nitrogen oxides decreasing combustion method which comprises: a first step of mixing a fuel and air with each other; a second step of bringing the mixture obtained in the first step into contact with a packed catalyst such that only catalytic combustion occurs; and a third step of adding a fresh supply of the fuel to a stream obtained from the second step to form a mixed gas and causing the mixed gas to undergo non-catalytic thermal combustion. The temperature of the packed catalyst is lower than the ignition temperature of the mixture and the adiabatic flame temperature of the mixed gas is lower than a temperature at which the nitrogen oxides occur.

Energy Technology Data Exchange (ETDEWEB)

Knock limitations are investigated using natural gas, with diesel pilot ignition, as a fuel for the 3406 DI-TA Caterpillar diesel engine. Thermodynamic properties at TDC are generated by computer and compared with experimental results. Exhaust emissions are analyzed. A comparison is made of dual-fuel operation relative to diesel. Observations are made to determine the onset of knock. The onset of knock is characterized as a function of engine speed, load, inlet manifold temperature, and air-fuel ratio (A/F). The conditions at the inset of knock are determined using cylinder pressure data. The most efficient operating range is determined with knock avoidance as a prime parameter.

Energy Technology Data Exchange (ETDEWEB)

The development of detailed chemical kinetic reaction mechanisms for analysis of autoignition and knocking of hydrocarbon fuels is described. In particular, kinetic processes of concern for the oxidation of complex hydrocarbon fuel molecules are emphasized. The wide ranges of temperature and pressure which are encountered by end gases in automobile engine combustion chambers result in extreme demands on reaction mechanisms which are intended to describe knocking conditions and predict rates of combustion and ignition. The reactions and chemical species which are most important in each temperature and pressure regime are discussed, and the validation of these reaction mechanisms through comparison with idealized experimental results is described. 53 refs., 8 figs., 5 tabs.

Energy Technology Data Exchange (ETDEWEB)

The pure xenon dc positive column discharge has been characterized for various xenon pressures, currents, and discharge tube radii. The absolute output at the 147 nm resonance transition has been measured using two independent techniques to yield the radiant emittance at 147 nm (power per unit surface area). The efficiency of 147 nm production is obtained by combining the measured radiant emittance with the measured electrical power per unit length deposited in the gas. The radiant emittance and the efficiency are the two principle figures of merit for characterizing the discharge as a source of VUV radiation. It is observed that the trends in efficiency and radiant emittance change substantially when the discharge transitions from two-step electron impact excitation/ionization at higher pressures to single-step electron impact ionization at lower pressures. Modeling of the xenon positive column discharge yields radiant emittance and efficiency ...

International Nuclear Information System (INIS)

One of the most effective removing processes of iodine species is what is called ''Iodox Process'', which contains oxidation and absorption of iodine species by highly concentrated nitric acid. The result of fundamental test with bubble column in this process had been reported. Present paper describes the fundamental experiment by the use of packed column. This experiment has been carried out to clear the effect of feed gas flow rate, nitric acid flow rate, nitric acid concentration, and methyl iodide concentration on removal efficiency of methyl iodide. The following results were obtained. The decontamination factor of methyl iodide (DF) increases exponentially with nitric acid concentration, which agrees with the result obtained by using the bubble column. The factor is in inverse proportion to feed gas flow rate, and is also almost independent of nitric acid flow rate and methyl iodide concentration. The relation between ...

CERN Document Server

Emission-line abundances have been uncertain for more than a decade due to unexplained discrepancies in the relative intensities of the forbidden lines and weak permitted recombination lines in planetary nebulae (PNe) and H II regions. The observed intensities of forbidden and recombination lines originating from the same parent ion differ from their theoretical values by factors of more than an order of magnitude in some of these nebulae. In this study we observe UV resonance line absorption in the central stars of PNe produced by the nebular gas, and from the same ions that emit optical forbidden lines. We then compare the derived absorption column densities with the emission measures determined from ground-based observations of the nebular forbidden lines. We find for our sample of PNe that the collisionally excited forbidden lines yield column densities that are in basic agreement with the column densities derived for ...

International Nuclear Information System (INIS)

A method was developed for the determination of plutonium in the soil samples by ICP-MS with TOA extraction chromatographic column. The optimized sample loading rate is below 0.2 mL/min (column inner diameter is 3.5 mm). Using hot 0.02 mol/L oxalic acid (H_2C_2O_4) in 0.16 mol/L HNO_3 to elute Pu from the solid phase in the column. The Pu recovery of 87.3%-96.8% in soil samples was obtained. The plutonium is separated with the ion exchange method in this work. Both extraction chroma- tography and ion-exchange methods efficiently remove the uranium and matrix interference from the ICP- MS measurement. The instrumental detection limit for "2"3"9Pu was 0.48 pg/mL, which corresponds to 1, 1 mBq/mL. (authors)

Energy Technology Data Exchange (ETDEWEB)

Acid mine drainage is a serious environmental problem caused by the oxidation of sulfide minerals that releases highly acidic, sulfate, and metals-rich drainage. In this study, alkaline industrial wastes were mixed with acid mine tailings in order to obtain neutral conditions. A series of column leaching tests were performed to evaluate the behavior of reactive mine tailings amended with alkaline-additions under dynamic conditions. Column tests were conducted of oxidized mine tailings combined with cement kiln dust, red mud bauxite, and mixtures of cement kiln dust with red mud bauxite. The pH results show the addition of 10% of alkaline materials permits the maintenance of near neutral conditions. In the presence of 10% alkaline material, the concentration of toxic metals such as Al, Cu, Fe, Zn are significantly reduced as well as the number of viable cells (Thiobacillus ferrooxidans) compared to control samples.

Energy Technology Data Exchange (ETDEWEB)

The Federal Aviation Administration (FAA) identified 17 accidents that may have resulted from fuel tank explosions on commercial aircraft from 1959 to 2001. Seven events involved JP 4 or JP 4/Jet A mixtures that are no longer used for commercial aircraft fuel. The remaining 10 events involved Jet A or Jet A1 fuels that are in current use by the commercial aircraft industry. Four fuel tank explosions occurred in center wing tanks (CWTs) where on-board appliances can potentially transfer heat to the tank. These tanks are designated as ''Heated Center Wing Tanks'' (HCWT). Since 1996, the FAA has significantly increased the rate at which it has mandated airworthiness directives (ADs) directed at elimination of ignition sources. This effort includes the adoption, in 2001, of Special Federal Aviation Regulation 88 of 14 CFR part 21 (SFAR 88 ''Fuel Tank System Fault Tolerance Evaluation ...

Energy Technology Data Exchange (ETDEWEB)

A phenomenological model of turbulent combustion has been developed and validated against data from wide ranging tests on a Ricardo E6 engine. Most tests used iso-octane, with a range of air fuel ratios and ignition timings, for tests at full throttle (with and without knock) and at part throttle. Some full throttle tests were also conducted with methanol and toluene. The engine performance was characterized by mean and coefficient of variation (CoV) of: the peak pressure, the maximum rate of pressure rise, the IMEP, the burn rate and flame speed measurements. The results have been used to argue that the cycle-by-cycle variations in combustion should be characterized by the CoV of IMEP in preference to the CoV of the maximum cylinder pressure. Evidence is also presented to support the observation that the cycle-by-cycle variations in combustion are lower when the early combustion is more rapid. It has also been shown that the CoV of IMEP is a minimum in the region ...

Energy Technology Data Exchange (ETDEWEB)

A simple method is presented for the separation of lead-203 from copper-backed thallium cyclotron targets. The procedure involves cation-exchange chromatography in hydrochloric acid and hydrochloric acid-acetone mixtures. Further purification involves anion-exchange chromatography in nitric acid-hydrobromic acid mixtures. A cation-exchange column containing 3.0 g of resin can handle as much as 15 g of thallium and 160 mg of copper. An anion-exchange column containing 3.0 g of resin can separate lead from up to 200 mg of thallium and 10 mg of copper. Separations are extremely sharp and less than 0.1 ..mu..g of thallium and less than 0.1 ..mu..g of copper remain in the lead-203 fraction.

British Library Electronic Table of Contents (United Kingdom)

This experimental study investigates the effectiveness of crossed inclined bars (X-bars) as joint shear reinforcement in exterior reinforced concrete beam-column connections under cyclic deformations. Test results of 20 joint subassemblages with various reinforcement ratios and arrangements including X-bars in the joint area are presented. The X-type, non-conventional reinforcement is examined as the only joint reinforcement and in combination with common stirrups or vertical bars. The experimental results reported herein include full loading cycle curves, energy dissipation values and a categorization of the observed damage modes. Based on the comparisons between the overall hysteretic responses of the tested specimens, it is deduced that joints with X-bars exhibited enhanced cyclic perfo...

Science.gov (United States)

Generally the photonic band gap (PBG) is a multi-variable function of several parameters related to the shape and size of the dielectric columns of photonic crystals (PhCs), and a time-consuming step-by-step scanning process for each parameter has to be used to find their best combination yielding maximum PBG. In this letter, the widely used Nelder-Mead simplex algorithm is introduced to optimize these parameters simultaneously to find a larger PBG for a new kind of two-dimensional (2D) hexagonal GaAs-Air PhC. This structure can be conveniently produced by the single-exposure holographic lithography, and the specific holographic design is also systematically investigated. This study reveals that the band gaps of PhCs made by holographic lithography may be widened by introducing irregularity of the columns and lowering the symmetry of the structure.

Energy Technology Data Exchange (ETDEWEB)

Real-time neutron radiography was demonstrated to be a viable and useful tool in studying water flow in unsaturated media. The experiment was designed to test the method for following water flow. The wetting front advance, water-flow patterns, and neutron attenuation density were observed in a 7.7-cm diameter sand column. The advance was fit with a simple i = A t/sup B/ equation yielding an excellent correlation. Theoretical calculations presented estimate the minimum and maximum detectable water content in various sizes of columns. The ability of real-time neutron radiography to allow both qualitative and quantitative spatial and time measurements to be made in an nonintrusive manner was demonstrated.

CERN Document Server

The Nystrom method is an efficient technique to speed up large-scale learning applications by generating low-rank approximations. Crucial to the performance of this technique is the assumption that a matrix can be well approximated by working exclusively with a subset of its columns. In this work we relate this assumption to the concept of matrix coherence and connect matrix coherence to the performance of the Nystrom method. Making use of related work in the compressed sensing and the matrix completion literature, we derive novel coherence-based bounds for the Nystrom method in the low-rank setting. We then present empirical results that corroborate these theoretical bounds. Finally, we present more general empirical results for the full-rank setting that convincingly demonstrate the ability of matrix coherence to measure the degree to which information can be extracted from a subset of columns.

Energy Technology Data Exchange (ETDEWEB)

This report presents the results of an experimental programme to determine the mass transfer and sorptive properties of selected glacial sand and clays from the Drigg Disposal Site operated by British Nuclear Fuels plc. The hydraulic conductivity of both the sand and clay has been determined and the sensitivity of this parameter to changing water chemistry investigated. The hydrodynamic dispersion properties of the glacial sand were measured in order to aid the interpretation of column sorption experiments. The sorption of strontium and uranium from groundwater onto clay and sand samples has been studied using through-diffusion, column and batch techniques. Employing the batch technique, the effect of a series of humic acid concentrations on distribution ratios for uranium and plutonium has also been investigated. Groundwater and trench leachate were used with both clay and sand. (author).

International Nuclear Information System (INIS)

Antibodies to hemoglobin have been studied with a radioimmunoassay which employs ["1"4C]carbamylated (= carbamoylated) hemoglobin S. An antiserum raised against hemoglobin S, which initially discriminated poorly between hemoglobins S and A, was fractionated by absorption to a column of Sepharose to which a synthetic peptide corresponding to the first 13 amino-acid residues of the #beta# chain of sickle hemoglobin had been covalently bound. A subpopulation of the antiserum was eluted from this column with 4 M guanidine . HCl. These antibodies showed binding to hemoglobin S but not to hemoglobin A and this interaction could be inhibited by the synthetic peptide. These antibodies, of demonstrated fine structural specificity, may be useful in the detection of sickle hemoglobin and in the study of its structure in solution.

International Nuclear Information System (INIS)

Twenty-two patients with vertebral primaries were registered in the Intergroup Ewing's Sarcoma Study between 1973 and 1977. The radiation doses to the primary tumors ranged between 3800 and 6200 rad. All patients received intensive combination chemotherapy. After a followup ranging between 14 and 62 months, 14 patients remained disease-free. All patients with primary tumor of the cervical and dorsal spine remained disease-free. Of eight patients with lesions in the distal spine, (sacrococcygeal region) six developed recurrence, in three a local recurrence was observed despite doses of 6000 rad or higher. Doses of 5000 rad or less (in addition to combination chemotherapy as used in the Intergroup Ewing's Study) appear adequate in controlling the primary tumors of the proximal segments of the spinal column.

Scientific Electronic Library Online (English)

Abstract in english A mathematical model has been developed for describing the dynamic operation of the N-formylmorpholine extractive distillation column and the corresponding solvent recovery column in the benzene extraction plant. The NRTL equation was used to calculate the equilibrium and thermodynamic properties of the mixtures. The validity of the model in terms of temperature, pressure and split fraction was examined using actual plant data at steady-state conditions. Comparison betwee (more) n model results and plant data shows good consistency. In order to improve the control of the process and selection of the optimal control strategy, the model was used to find the optimum values of the constants of the controllers with Nelder-Mead algorithm during unsteady-state operation by minimizing the deviation from steady-state conditions. The outcome of this study could be used by operators and engineers to increase the productivity of the ...

British Library Electronic Table of Contents (United Kingdom)

Abstract In the work, a rapid, simple and high-throughput sample preparation method was developed for the determination of sulfonamide (SA) antibiotic residues in chicken breast muscle. The extraction and clean-up were online combined and up to 20 samples can be treated simultaneously in 6-min. The SAs were first extracted with acetonitrile under the action of microwave energy, and then the extract was directly introduced into the SPE column for on-line clean-up and concentration. Subsequently, the SAs eluted from the SPE column were determined by liquid chromatography-tandem mass spectrometry. The precisions of extraction results of 20 samples were in the range of 4.9-7.4%. The limits of detection and quantification obtained were in the range of 2.4-3.6-ng/g and 8.6-11.3-ng/g for SAs, res...

International Nuclear Information System (INIS)

In this letter, the effect of vacancies generated by preirradiated laser on dopant diffusion and activation in preamorphized silicon substrate has been studied. Laser-induced melting in silicon was used to generate excess vacancies near the maximum melt depth before silicon substrate amorphization and subsequent boron implantation. We demonstrate that by matching the preirradiated laser melt depth with the implant amorphize depth, it can effectively reduce the silicon self-interstitials released from the end-of-range defect band. The results show great suppression in boron transient enhanced diffusion and significant removal of end-of-range defects. This is attributed to the recombination of laser-generated excess vacancies with preamorphizing induced free silicon interstitials at the end-of-range region.

International Nuclear Information System (INIS)

The basic relationships of the convolution/superposition dose calculation technique are reviewed, and a modelling technique that can be used for obtaining a satisfactory beam model for a commercially available convolution/superposition-based treatment planning system is described. A fluence energy spectrum for a Co-60 treatment machine obtained from a Monte Carlo simulation was used for modelling the fluence spectrum for a Rokus M machine. In order to achieve this model we measured the depth dose distribution and the dose profiles with a Wellhofer dosimetry system. The primary fluence was iteratively modelled by comparing the computed depth dose curves and beam profiles with the depth dose curves and crossbeam profiles measured in a water phantom. The objective of beam modelling is to build a model of the primary fluence that the patient is exposed to, which can then be used for the calculation of the dose deposited in the ...

Energy Technology Data Exchange (ETDEWEB)

Interest in the tribological properties of plasma nitriding has increased substantially over the past years because plasma nitriding provides a high nitride depth and improved hard facing. The present study examines the tribological properties of AISI H11 plasma nitrided, hot-worked steel. Different nitriding temperatures and durations were considered. Characterization of the composite structures was investigated with wear tests, x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and microhardness tests. The depth profile of the nitrided zone was measured using the nuclear reaction analysis (NRA) technique. Plasma nitriding affected the microhardness, wear properties, and morphology considerably. Increase in process temperature increased the nitride zone depth.

British Library Electronic Table of Contents (United Kingdom)

In this paper, the spatial-temporal dynamics of soil moisture content was investigated in an evergreen broad-leaved forest and a tea tree plantation in Ailao Mountains, which was dominated by Fagaceae (Castanopsis wattii and Lithocarpus xylocarpus). Soil moisture content was studied between January 2005 and December 2006 at different depths (from 0-150 cm) with a neutron probe. The results showed that mean soil moisture content in the evergreen broad-leaved forest was usually higher than in the tea tree plantation in the dry season, whereas it was lower than the tea tree plantation in the rainy season. In addition, mean soil moisture content was depth dependent, and in the 10-50 cm layer the spatial variability was due to the active root zone within this depth area in two types of land use...

British Library Electronic Table of Contents (United Kingdom)

Electrochemical discharge machining (ECDM) is a promising hybrid process for high-performance machining of non-conductive glass. ECDM drilling has been found to have different characteristics and material removal mechanisms in discharge regime (less than 300??m in depth) and hydrodynamic regime (more than 300??m in depth); however, these regimes are never separately modeled in existing ECDM models, which leads to large prediction error, especially at low applied voltages and high machining depths. Until now, no model is particularly designed for discharge regime, where most material is removed. In this paper, a finite element based model for ECDM drilling in discharge regime is presented. Material removal subjected to a single spark was simulated using finite element method. The drilling d...

CERN Document Server

We have conducted a systematic investigation of the origin and underlying physics of the line--line and line--continuum correlations of AGNs, particularly the Baldwin effect. Based on the homogeneous sample of Seyfert 1s and QSOs in the SDSS DR4, we find the origin of all the emission-line regularities is Eddington ratio (L/Ledd). The essential physics is that L/Ledd regulates the distributions of the properties (particularly column density) of the clouds bound in the line-emitting region.

Energy Technology Data Exchange (ETDEWEB)

Research over a three year time span involved the study of multiphase flow useful to understanding the scaleup of coal liquefaction reactors. We attempted to establish the flow patterns and their boundaries in which a direct coal liquefaction, large diameter, bubble column operates. A flow map has been proposed in which coal slurry properties can be input to determine the flow pattern boundaries at reactor operating conditions. Gas holdup and bubble diameters have been measured under different conditions of gas and liquid flow rate. These have been used to determine interfacial area in bubble columns. An equation for the estimation of interfacial area in the bubble-slug flow pattern has been proposed. It has also been established that gas holdup and thus interfacial area depends strongly on the gas distribution in the column. Porous plate gas distributors can yield gas holdups twice as large as sieve plate distributors. ...

Energy Technology Data Exchange (ETDEWEB)

Recognizing the importance of {sup 99m}Tc and {sup 99m}Tc-based radiopharmaceuticals in nuclear medicine, the Philippine Nuclear Research Institute has initiated research on the development of column-type generators for {sup 99m}Tc using {sup 99}Mo in the form of a gel. The use of reactor-produced {sup 99}Mo will reduce the country's dependence on the importation of commercial generators based on fission product molybdenum-99. However, the relatively low specific activity of {sup 99}Mo must be compensated by the high adsorption capacity of the column material for molybdenum. A procedure based on the incorporation of low activity {sup 99}Mo into a zirconium molybdate gel matrix was adopted with reasonable success. Because the properties of the gel vary considerably with conditions of synthesis, the following parameters were carefully controlled: pH, concentration, temperature, order of mixing of the reactant solutions and conditions of ...

Energy Technology Data Exchange (ETDEWEB)

Sewage gas or biogas as a product of anaerobic digestion contains methane and carbon dioxide as its main components. Biogas is scrubbed off carbon dioxide in absorption columns and purified to natural-gas quality. The purified gas then is piped to the gas pressure control station and fed into the public network. Description of process and plant is given.

Energy Technology Data Exchange (ETDEWEB)

The purpose of this invention is to assure operating reliability of a Mandrel head in tubes of various diameters. This goal is achieved in that it is equipped with movable expanding sectors, which are installed on a rigid conical plunger dye. It is also equipped with spring-loaded conical slides blocks which are installed on a shaft. The upper ends of the sectors of the sectorial head are attached by hinges to a rigid cone shaped plunger dye. The lower ends are installed with the possibility of interacting with the slide blocks.

International Nuclear Information System (INIS)

Under the current design philosophy, reactor structures are to be designed to withstand large inelastic deformation caused by strong and severe ground motion. The design of the main structural elements and their connections are to be such that they always fail in ductile mode. This will ensure large energy absorption capacity of the structures under seismic excitation and avoid sudden and brittle failure of the structure. Over the years, a number of experimental investigations have been carried out on RC beam- column joints to study their behaviour and strength. However, these studies mostly pertain to small scale joints of moment resisting frame of residential buildings and commercial complexes. Information on full scale joints existing in NPP structures are scanty. Therefore, experimental programme was planned in the laboratory to construct identical large sized joints with the same reinforcement percentage and detail as that of the existing joints in NPP ...

Science.gov (United States)

Americium 242m and americium 242 were prepared by reactor irradiation of americium 241 as its diphthalocyanine complex. The product atoms were extracted from the parent isotope at an enrichment factor of 10. A Dowex 50 chromatographic column raised the factor to 24.6.

Energy Technology Data Exchange (ETDEWEB)

Different types of generators have been developed for the convenient use of {sup 99m}Tc as the demand for this radioisotope is strong. Currently, the demand for {sup 99m}Tc is more than 80 % of the total demand for medical isotopes in the world. A {sup 99m}Tc generator, in general, is composed of a column packed with ceramic adsorbent, tubing, eluent reservoir or vials, collection vials, and shielding. The key technology to develop a good generator is how to load {sup 99}Mo as much as possible while maintaining the quality of eluted {sup 99}mTc as good as possible. The technology is well developed and already available commercially for the case of the fission {sup 99}Mo/{sup 99}mTc because loading of few curries of {sup 99}Mo on a conventional adsorbent, i.e. alumina is not a serious task in the chemical point of view. However, the current infrastructure of the supply of {sup 99}Mo to the world market is sturdy as the research reactors are getting aged. In this ...

CERN Document Server

In the positive column of a neon glow discharge, two different types of ionization waves occur simultaneously. The low-dimensional chaos arising from the nonlinear interaction between the two waves is controlled by a continuous feedback technique. The control strategy is derived from the time-delayed autosynchronization method. Two spatially displaced points of observation are used to obtain the control information, using the propagation characteristics of the chaotic wave.

International Nuclear Information System (INIS)

We have investigated the characteristics of ion-beam-induced spontaneous etching (IBISE) of GaAs in Cl_2 ambient by using a Ga-focused ion beam (FIB) with an energy ranging from 3 to 15 keV. The etched depth of the irradiated region was more than 20 times greater than that of unirradiated region. When the sputtered depth by FIB irradiation amounted to around 8 A at each ion energy, the etched depth in Cl_2 ambient for 1 hour became saturated. The saturated etched depths were 450, 550, 750 and 800 A at the ion energy of 3, 5, 10 and 15 keV, respectively. The residual damage of the etched surface was also investigated by photoluminescence (PL) measurement. The maximal PL intensity was obtained at around the threshold dose of IBISE and increased with decreasing ion energy. The full recovery of PL intensity was observed at the ion energy of 3 keV after annealing at 400degC. (author).

Energy Technology Data Exchange (ETDEWEB)

Direct current (DC) glow discharge plasma nitriding was carried out on three selected surface-roughened AISI 304 stainless steel samples at 833 K under 4 mbar pressures for 24 h in the presence of N{sub 2}:H{sub 2} gas mixtures of 50 : 50 ratios. After plasma nitriding, the phase formation, case depth, surface roughness, and microhardness of a plasma-nitrided layer were evaluated by glancing angle x-ray diffractogram, optical microscope, stylus profilometer, and Vickers microhardness tester techniques. The case depth, surface hardness, and phase formation variations were observed with a variation in initial surface roughness. The diffraction patterns of the plasma-nitrided samples showed the modified intensities of the {alpha} and {gamma} phases along with those of the CrN, Fe{sub 4}N, and Fe{sub 3}N phases. Hardness and case depth variations were observed with a variation in surface roughness. A maximum hardness of 1058 Hv ...

UK PubMed Central (United Kingdom)

BackgroundRecent research highlights the promise of remotely sensed aerosol optical depth (AOD) as a proxy for ground-level particulate matter with aerodynamic diameter ≤...Full Text Available

Science.gov (United States)

... at depths greater than 29 m. Egmont Deep Seismic Stratigraphy Seismic profile data indicate that both the mouth ... 131. CrossRefDuncan, D. S. 1993. Neogene to Recent Seismic Stratigraphy of the Lower ...

International Nuclear Information System (INIS)

Electron probe microanalysis (EPMA) offers high sensitivity and high accuracy in quantitative measurements of chemical compositions and mass coverages. Owing to the low detection limits of the wavelength-dispersive technique, monolayers with mass coverages of about 0.05 pg cm z can be detected. Assuming a density of 5 g cm--3 this corresponds to a thickness of 0.1 nm. With these advantages in mind, EPMA was extended to depth profile analysis in the sub-micron range using a surface removal technique. The present paper shows how depth profile analysis can be improved by combining EPMA and the focused ion beam (FIB) technique. The focused ion beam system uses a Ga+ ion beam. The ion beam allows the milling of defined geometries on the nanometer scale, so that very shallow bevels with exactly defined angles in relation to the surface can be obtained. Low surface damage is expected due to low sputtering effects. Calibrated WDX measurements along the ...

International Nuclear Information System (INIS)

A quantitative transmission electron microscopy (TEM) study on the depth profile of extended defects, formed after Si implantation, has been carried out. Two different Si"+ implant conditions have been considered. TEM analysis for the highest energy/dose shows that #left brace#1 1 3#right brace# defects evolve into dislocation loops whilst the defect depth distribution remains unchanged as a function of annealing time. For the lowest energy/dose, #left brace#1 1 3#right brace# defects grow and dissolve while the defect band shrinks preferentially on the surface side. At the same time, extraction of boron transient enhanced diffusion (TED) as a function of depth shows a decrease of the supersaturation towards the surface, starting at the location of the defect band. The study clearly shows that in these systems the silicon surface is the principal sink for interstitials. The results provide a critical test of the ability of ...

UK PubMed Central (United Kingdom)

We report on a high resolution, monolithic crystal PET detector design concept that provides depth of interaction (DOI) positioning within the crystal. Our design utilizes a novel sensor on...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The physical properties of polymer blends consisting of one or more crystallizable components are affected by the microstructure of these materials. In particular, the degree of crystallinity can be influenced by processing parameters, and the crystallinity, as well as the phase distribution, may vary as a function of depth through an injection molded part Conventional x-ray diffraction techniques can provide information regarding both phase composition and degree of crystallinity, but, because of the relative transparency of these materials to wavelengths generally available in the laboratory, these techniques provide information representative of only the bulk. By employing parallel beam optics at varying grazing incidence angles, the x-ray sampling depth can be varied without loss of resolution. This technique can be used to vary the effective analysis depth from the top several hundred angstroms for low razing incidence ...

Energy Technology Data Exchange (ETDEWEB)

Three popular imaging methods were used to carry out seismic migration from the Alberta foothills: Kirchhoff integral, reverse-time and explicit finite-difference migration methods. The imaging comparisons of reverse-time, Kirchhoff and f-x post-stack depth migration leads to the following conclusions. All of the three migration methods can provide acceptable and well-imaged intermediate results on the simplest model. Post-stack migration was not very sensitive to the accuracy of the velocity field once a reliable structural stack was available. With respect to the imaging accuracy and calculation cost, the Kirchhoff migration method seemed to be superior to reverse-time and f-x migration algorithms because its results on different kinds of velocity cases were basically kept coherent and consistent with the velocity model given by Mobil. Because of the lack of an accurate velocity field, reverse-time migration was less stable than the other two imaging methods, ...

UK PubMed Central (United Kingdom)

We investigated the deep-sea fossil record of benthic ostracodes during periods of rapid climate and oceanographic change over the past 20,000 years in a core from intermediate depth in the northwestern...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

For a new and practical {sup 99m}Tc generator using not (n, f){sup 99}Mo, but (n, {gamma}){sup 99}Mo, an inorganic polymer adsorbent framed with oxygen-zirconium-chlorine bonds with a high adsorption performance of Mo has been developed; the polymer adsorbent was named PZC. The amounts of {sup 99}Mo (Mo) adsorbed are stably more than 250 mg/g(PZC). But, the current experiments with 0.5 MBq to 1.85 GBq of {sup 99}Mo gave a subject that the breakthrough of {sup 99}Mo in the elution of {sup 99m}Tc from the adsorbent was 0.05-0.5 %, although the breakthrough of Zr was less than the detection limit of 5 x 10{sup -2} mg(Zr) to 1 g of PZC, and {sup 99m}Tc was eluted constantly with 78{+-}4%. To apply the adsorbent as a generator commercially in Japan, the {sup 99}Mo breakthroughed from the generator must be suppressed to less than 0.15 kBp({sup 99}Mo)/MBq({sup 99m}Tc) by law which is equivalent to 0.015 %, and the {sup 99}Mo breakthrough is controlled practically to less than 10{sup -2} of ...

International Nuclear Information System (INIS)

The mine dumps that arise from the gold mining operations in South Africa are a potential source of high concentrations of radon (222"Rn). Studying the diffusion of radon and the emanation from the soil will help to deduce the radon flux from these dumps to identify the problem areas for rehabilitation. This study describes measurements of the emanation coefficient and the modelling of the depth profile of the radon activity concentration, which is compared to a depth profile that was measured on such a mine dump. Emanation coefficients ranging from 0.13 to 0.39 have been obtained.

Energy Technology Data Exchange (ETDEWEB)

The rate of corrosion of hardened cement paste in solutions of nitric, hydrochloric, sulfuric, acetic and formic acids was compared. Corrosion in solutions of acetic and nitric acids with different concentrations was studied in more detail. The results made it possible to obtain the relationships expressing the influence of concentration and the time of action of acid solutions on the depth of corrosion. The rates of corrosion in nitric acid solutions during the first 3 years were about 2 to 4 times that in acetic acid solutions, depending on the concentration.

British Library Electronic Table of Contents (United Kingdom)

Activity concentrations of some anthropogenic radionuclides (90Sr, 137Cs, 238Pu, 239+240Pu and 241Am) have been measured in the surface of marine sediments along the Saudi coast of the Arabian (Persian) Gulf. The samples were collected at different locations and water depths. The spatial distribution of the concentrations of the measured radionuclides showed a heterogeneous pattern and is independent of location or water depth. The obtained results are discussed and some conclusions are drawn.

Science.gov (United States)

The MgF{sub 2} monocrystals were irradiated at room temperature with 390 keV B{sup +} ions up to the fluence of 10{sup 16} cm{sup -2}. The irradiated samples were (isochronally and isothermally) annealed in high vacuum at the temperatures 200 deg. C, 300 deg. C, 400 deg. C, 500 deg. C, 600 deg. C and 700 deg. C for the times ranging from 2-100 hours. After each annealing step, the boron depth distribution was determined using the neutron depth profiling technique. As implanted, the depth distributions of boron exhibited standard Gaussian-like forms, but the evaluated profile parameters, R{sub P} = 960 nm and {delta}R{sub P} = 140 nm, were higher than those calculated using the SRIM code (R{sub P} = 870 nm and {delta}R{sub P} = 115 nm). Annealing at temperatures up to 400 deg. C did not change the depth profiles. Annealing at 600 deg. C, however, led to a one-way gradual transfer of the boron atoms from ...

Energy Technology Data Exchange (ETDEWEB)

The reduced polluting emissions make natural gas a quite interesting alternative fuel for automotive applications. Therefore a car diesel engine has been transformed into a dual fuel engine with pilot injection via the common rail injection system used to ignite the methane-air charge. Standard injection pumps show a certain instability at low flow rates and high engine speed. On the opposite the new common rail system allows to ignite the fuel in all conditions with an amount of gas oil less than 8% of the entire energy required by the engine was enough to ignite the fuel. Furthermore, a power increase has been obtained, with an overall efficiency equal to or even higher than a conventional engine. The article deals with a series of test carried out on 1929 cm{sup 3} direct injection turbo-charged engine and presents the preliminary results. [Italian] La riduzione delle emissioni inquinanti rende il metano un combustibile ...

British Library Electronic Table of Contents (United Kingdom)

In this work, a new sol-gel auto-combustion method has been performed to synthesize single phase nickel ferrite nanocrystalline powders by using n-cetyltrimethylammonium bromide, as a cationic surfactant. The gels were prepared from ferric and nickel nitrates and citric acid. Ammonia was used as pH adjusting agent as well. The effects of the surfactant on the after combustion calcination process and the reduction of the resulting powder crystallite size which affects the magnetic properties of the material were investigated by XRD and DTA/TGA techniques. The results showed that the ignition of the gels in air have a self-propagating behavior. Addition of surfactant to the starting solution affected the crystallite size of the synthesized powders and their phase constitution. The crystallit...

Energy Technology Data Exchange (ETDEWEB)

The experimental survey about the heat transfer between the working fluid and the combustion chamber wall with a direct injection diesel engine has shown the production of a soot layer with increasing loads on the combustion chamber wall. Because the combustion process of methanol occurs without the formation of wall deposits, the same engine spark ignitioned with methanol at the same conditions has shown a higher heat transfer coefficient. Because the heat losses do not only depend on the heat transfer coefficient but also on the driving temperature difference between the working fluid and the combustion chamber wall, the methanol engine with corresponding process management showed lower heat losses than the diesel engine at nearly the same load. (orig./HW)

Energy Technology Data Exchange (ETDEWEB)

The report presents the results of a Gas Research Institute (GRI) program to evaluate the technical and economic aspects of design options proposed by the U.S. Department of Energy (DOE) for reducing the energy consumption of residential ranges and ovens as mandated by the National Appliance Energy Conservation Act (NAECA) of 1987. The study shows that none of the proposed DOE design options are justified except electric ignition for stand-alone cooktops, based on life-cycle costs, loss of consumer utility, safety, technical considerations, or food quality considerations. An individual range uses so little gas during the year (approximately $14/year for a self-cleaning range) that it is difficult to justify any design modification, since the cost of even a simple modification could not be recovered on the basis of gas saved.

British Library Electronic Table of Contents (United Kingdom)

Natural gas is a promising alternative fuel to meet strict engine emission regulations in many countries. Natural gas engines can operate at lean burn and stoichiometric conditions with different combustion and emission characteristics. In this paper, the operating envelope, fuel economy, emissions, cycle-to-cycle variations in indicated mean effective pressure and strategies to achieve stable combustion of lean burn natural gas engines are highlighted. Stoichiometric natural gas engines are briefly reviewed. To keep the output power and torque of natural gas engines comparable to those of their gasoline or Diesel counterparts, high boost pressure should be used. High activity catalyst for methane oxidation and lean deNOx system or three way catalyst with precise air-fuel ratio control str...

Energy Technology Data Exchange (ETDEWEB)

The authors study technological safety of installing a water spray pressure vessel between electrostatic deduster and coal sludge ducts. These sprays are in use elsewhere for steam generator ash removal. Dust ignition and explosion tests were carried out to examine flame and pressure wave propagation through the vessel into ducts. Water jet diameter, amount of water sprayed and coal dust removed were varied. Pressure waves exceeded 250 Pa. Test results show the vessel to be suitable for installation in briquetting plants due to its flame and explosion barrier effect and extermination of smoldering dust fires. The only disadvantage of the vessel is seen as its water and electric power consumption: about 8 m/sup 3//h of water and 1.5 kW/h of power per vessel serving dedusters of a 2,200 m/sup 2/ rotary brown coal dryer. (MOS).

British Library Electronic Table of Contents (United Kingdom)

Abstract: The recent National Academy of Sciences report on forensic sciences states that the study of fire patterns and debris in arson fires is in need of additional work and eventual standardization. We discuss a recently introduced method that can provide predicted evaporation patterns for ignitable liquids as a function of temperature. The method is a complex fluid analysis protocol, the advanced distillation curve approach, featuring a composition explicit data channel for each distillate fraction (for qualitative, quantitative, and trace analysis), low uncertainty temperature measurements that are thermodynamic state points that can be modeled with an equation of state, consistency with a century of historical data, and an assessment of the energy content of each distillate fraction...

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The factors influencing premixed burning and the importance of premixed burning on the exhaust emissions from a small high-speed direct-injection diesel engine were investigated. The characteristics of premixed and diffusion burning were examined using a single-zone heat-release analysis. The mass of fuel burned in premixed combustion was found to be linearly related to the product of engine speed and ignition-delay time and to be essentially independent of the total amount of fuel injected. Accordingly, the premixed-burned fraction increased with increasing engine speed, with decreasing fuel-air ratio and with retarding injection timing. The hydrocarbon emissions did not correlate well with the premixed-burned fraction. In contrast, the oxides of nitrogen emissions were found to increase with decreasing premixed-burned fraction, indicating that diffusion burning, and not premixed burning, is the primary source of oxides of nitrogen emissions.

International Nuclear Information System (INIS)

In evaluating commercialization prospects for natural gas fuelled vehicles, this paper compares the performance and emission quality of these innovative vehicles with those using conventional fuels - gasoline and diesel fuels. Assessments are made of the state-of-the-art of current technology relative to fuel storage, air/fuel mixture preparation, in cylinder combustion processes and pollution control. The analysis evidences that while natural gas is an excellent fuel for spark ignition engines, in transport applications its use is hampered by large storage volume requirements and weight. Moreover, the air/fuel mixture preparation, combustion process and exhaust-gas cleaning require a greater research and development effort to make this alternative fuel economically and environmentally competitive with conventional fuels.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a low emission duel fuel engine system. It comprises: a dual fuel engine having a combustion chamber; a fuel oil supply connected to the engine; a fuel gas supply connected to the engine; and means connected between the fuel oil supply and the engine for injecting fuel oil into the engine. The means connected between the engine and fuel oil supply limiting the injection of fuel oil to the combustion chamber to pilot ignition quantities only, wherein the limiting means includes means for limiting the injection of fuel oil such that the exhaust emission of NO{sub x} is at an emission rate of less than 1 GM/PH-HR, whereby the exhaust emission performance of the dual fuel engine is enhanced.

Energy Technology Data Exchange (ETDEWEB)

The Bureau of Mines has investigated the hazards of military explosives dispersed as dust clouds in a 20-L test chamber. For purposes of personnel safety, the spark ignitability of the explosives in the form of unconfined dust layers was also studied. The 20-L data show that most of the explosives dusts were capable of sustaining explosions as dust clouds dispersed in air and some dusts were even capable of sustaining explosions when dispersed in nitrogen. The finest sizes of explosives dusts were less reactive than the larger sizes; this is opposite to the particle size effect observed previously for the pure fuel dusts. The data for the explosives dusts were compared to those for pure fuel dusts. 27 refs., 47 figs.

British Library Electronic Table of Contents (United Kingdom)

Flame propagating through zirconium particle cloud in a small-scale vertical rectangle chamber was investigated experimentally. In the experiments, the zirconium quoted 99% purity was used and the diameter of particles was distributed 1?22 ?m. The zirconium dust was dispersed into the chamber by air flow and ignited by an electrode spark. A high-speed video camera was used to record the images of the propagating flame. Micro-thermocouples, schlieren optical system and microscopic lens were used to obtain temperature profiles and flame structure, respectively. Based on the experimental results, flame propagation characteristics and flame structure of zirconium particle cloud were analyzed. The propagation velocity of the flame is quite slow in the initial 14 ms and then accelerates to maxim...

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In seeking ways to reduce emissions from two-stroke locomotive type engines, the Navy has evaluated dual-fuel conversions operating on a compression ignition cycle, using up to 94% natural gas and 6% diesel pilot fuel. The Navy has conducted an evaluation and test program under the direction of Dr. Normnn L. Helgeson, at the Naval Facilities Engineering Service Center in Port Hueneme, California. Of the Navy`s many diesel engines, those installed in its MUSE (mobile utility support equipment) units for temporary electrical power were the first Navy off-road engines to be affected by emissions regulations. Most of the units are powered by the EMD 645 engine, and when burning diesel fuel do not meet the emission requirements in many areas of the country. This paper discusses the changes and results of the conversion and shakedown tests.

Energy Technology Data Exchange (ETDEWEB)

Recently, utilization of natural gas, which is considered to be one of most important alternative fuels for petroleum, has been marked. As thermal efficiency of dual-fuel engine is higher than those of other prime movers with gaseous fuel, i.e., spark-ignited gas engine or gas turbine, it is possible to construct fuel-economical gas power plants with dual-fuel engines. However, its horsepower has been limited to the rather lower range. In 1984, NKK succeeded in developing large-sized dual-fuel engines based on the Pielstick PC4 diesel engine. The horsepower is 1200 HP/cyl, i.e. 21,600 HP for 18-cyclinder engine.

Science.gov (United States)

The feasibility of this procedure was investigated using minerals and ore specimens. The substances were ground then fused using LiBO/sub 2/, quenched with 3% HNO/sub 3/ or mixtures of the acid with 2.5% tartaric acid or 30% H/sub 2/O/sub 2/. The quenched melt was usually completely dissolved within 20 min by placing the beakers in an ultrasonic bath. If any residue was detected, appropriate changes were made in the procedure. Once the procedure has been optimized, any remaining black particles were filtered. If these particles disappeared upon subsequent ignition, they were presumed to have been graphite. Most of the refractory minerals investigated should be expected to be converted to soluble form by this process. 1 table.

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The catalytically stabilised thermal combustion (CST) of lean hydrogen-air mixtures was investigated numerically in a turbulent channel flow configuration using a two-dimensional elliptic model with detailed heterogeneous and homogeneous chemical reactions. Comparison between turbulent and laminar cases having the same incoming mean properties shows that turbulence inhibits homogeneous ignition due to increased heat transport away from the near-wall layer. The peak root-mean-square temperature and species fluctuations are always located outside the extent of the homogeneous reaction zone indicating that thermochemical fluctuations have no significant influence on gaseous combustion. (author) 4 figs., 6 refs.

International Nuclear Information System (INIS)

The modeling methods used to compute the neutron-induced activation of target and near-target materials in the NIF facility are presented. A detailed space and energy description of the neutron environment in the different materials is provided. A new capability has been developed to treat in a general way the activation of debris produced in an operational regime of yield and no-yield experiments. First calculations are addressed to analyze the activity of the debris into the target chamber. The contribution of the different components to activity, interior dose rates, and waste disposal rating (WDR) is determined. The importance of the activation coming from primary irradiation in the target, and from secondary irradiation in debris deposited onto the first wall is assessed. Finally, waste hazards of the activated debris when removed out of the chamber and stored are analyzed. (authors)

International Nuclear Information System (INIS)

Service water, 100 l each, was collected at an intake of a water treatment plant and at a tap after water was left running for five minutes. The carriers of strontium and cesium were added to water immediately after sampling, and the sample was vigorously stirred and filtered. Then it was passed through a cation exchange column at a rate of 80 ml/min. Strontium and cesium were eluted with hydrochloric acid from the cation exchange column, and separated. After the radiochemical separation, the mounted precipitates were counted for activity using low background beta counters normally for 60 min. Net sample counting rates were corrected for counter efficiency, recovery, self absorption and decay to obtain the content of strontium-90 and cesium-137 radioactivity per sample aliquot. From the results, concentrations of these nuclides in the original sample were calculated. The maximum values obtained were 0.29 pCi/l of Sr-90 in Kyoto in August, 1981, ...

Science.gov (United States)

Newly commercialized Fourier transform Raman spectroscopic instrumentation provides a simpler alternative for vibrational spectroscopic analysis. Instrument vendors currently design for laboratory use, but there are many potential process applications of these stable, easy to use instruments. Raman spectroscopy is highly suited to analysis of aqueous samples. Near infrared excitation minimized fluorescence interference and allows for remote operation via fiber optic probes. The Department of Energy has funded research at the Measurement and Control Center to establish the utility of this method for on-line composition analysis in distillation columns. Laboratory evaluation and instrument employs an air-cooled laser and a thermoelectrically cooled detector. The device is mounted on a three by foot cart for convenient location in control rooms. Current fiber optic extension cables allow for analysis in a cell thirty five meters from the instrument. Application of the ...

Energy Technology Data Exchange (ETDEWEB)

A brief comparative review of possible mercury free fluorescent lighting technologies is presented, including rare-gas positive column discharges, molecular discharges, and dielectric barrier discharges. Detailed experimental results on xenon positive column discharges will then be considered. In order to judge whether xenon-based discharges are a viable UV source it is necessary to measure the radiant emittance (power per unit area) for the vacuum ultraviolet (VUV) resonance xenon emission at 147 nm. Two techniques to determine the VUV radiant emittance have been developed and applied to xenon discharges. One method combines the measured resonance level density using absorption spectroscopy and a calculation of the trapped decay rate for the resonance radiation to arrive at the radiant emittance at 147 nm. A second method utilizes a direct measurement of the radiance (power per unit area per unit solid angle) at 147 nm using a calibrated VUV ...

International Nuclear Information System (INIS)

One way to intensify heat and mass transfer processes in column-type equipment is through use of contact devices with directional gas phase injection into a liquid. Making the perforations at an angle to the tray plane permits a rise in the permissible gas velocity in the column, since inertial force adds to gravity during separation. Different arrangements of the jet-forming elements relative to one another and to partitions and baffle-type contacts installed on the trays can improve phase contact conditions and intensify heat and mass transfer. Design of jet-type trays for a specific purpose requires that the influence of jet-forming, element design parameters on at least the fluid dynamic situation on the tray be known. In this work, the authors evaluate the influence of tab bend-up angle on jet tray working characteristics. These investigations demonstrate that the jet inclination angle (the angle of maximum gas velocity in the jet) exceeds ...

British Library Electronic Table of Contents (United Kingdom)

Forty synthetic food colors were determined in drinks and candies by reversed-phase high-performance liquid chromatography with photodiode array detection. The following food colors were analyzed within 19min using a short analytical column (50mmx4.6mm i.d., 1.8mm) at 50degreeC with gradient elution: Ponceau 6R, Tartrazine, Fast yellow AB, Amaranth, Indigotine, Naphthol yellow S, Chrysoine, Ponceau 4R, Sunset yellow FCF, Red 10B, Orange G, Acid violet 7, Brilliant black PN, Allura red AC, Yellow 2G, Red 2G, Uranine, Fast red E, Green S, Ponceau 2R, Azorubine, Orange I, Quinoline yellow, Martius yellow, Ponceau SX, Ponceau 3R, Fast green FCF, Eosine, Brilliant blue FCF, Orange II, Orange RN, Acid blue 1, Erythrosine, Amido black 10B, Acid red 52, Patent blue V, Acid green 9, Phloxine B, Ben...

Energy Technology Data Exchange (ETDEWEB)

Polycyclic aromatic hydrocarbons (PAH`s) are ubiquitous hydrophobic organic pollutants in the marine environment. Many of the PAM`s are classified as possible carcinogens or mutagens, therefore they are of considerable concern to human and environmental health. The highest concentrations are found in coastal regions due to anthropogenic activities including oil spills, tanker operations, incomplete fossil fuel combustion and runoff. The sources and distribution of PAM`s in sediments are fairly well known, while the fate and transport of PAH`s in the marine environment are less known. Desorption is an important factor influencing the fate and transport of hydrophobic molecules at the seawater/sediment interface. The desorption of PAH`s from contaminated marine sediments to the water column/pore water affects the availability of the pollutant to biota. The sorption of PAH`s is determined in part by the organic carbon content of the sediments. The presence of ...

International Nuclear Information System (INIS)

Neutron semiconductor detectors for neutron counting and neutron radiography have an increasing importance. Simple silicon neutron detectors are combination of a planar diode with a layer of an appropriate neutron converter such as 6LiF. These devices have limited detection efficiency of not more than 5%. The detection efficiency can be increased by creating a 3D microstructure of dips, trenches or pores in the detector and filling it with a neutron converter. The first results related to the development of such devices are presented. Silicon detectors were fabricated with pyramidal dips on the surface covered with 6LiF and then irradiated by thermal neutrons. Pulse height spectra of the energy deposited in the sensitive volume were compared with simulations. The detection efficiency of these devices was about 6.3%. Samples with different column sizes were fabricated to study the electrical properties of 3D structures. Charge collection efficiencies in silicon ...

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In a study where the removal of heavy metals from wastewater is the primary aim, the biosorption of heavy metals onto biosolids prepared as Pseudomonas aeruginosa immobilized onto granular activated carbon was investigated in batch and column systems. In the batch system, adsorption equilibriums of heavy metals were reached between 20 and 50 min, and the optimal dosage of biosolids was 0.3 g/L. The biosorption efficiencies were 84, 80, 79, 59 and 42 % for Cr(VI), Ni(II), Cu(II), Zn(II) and Cd(II) ions, respectively. The rate constants of biosorption and pore diffusion of heavy metals were 0.013-0.089 min{sup -1} and 0.026-0.690 min{sup -0.5}. In the column systems, the biosorption efficiencies for all heavy metals increased up to 81-100 %. The affinity of biosorption for various metal ions towards biosolids was decreased in the order: Cr = Ni > Cu > Zn > Cd. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Energy Technology Data Exchange (ETDEWEB)

Wastewater from a food-manufacturing plant with a low concentration of organic matter was treated at 37 centigrade in an anaerobic fluidized-bed reactor or in an upflow anaerobic sludge blanket. As the influent TOC (total organic carbon) concentration decreased, the TOC removal efficiency in these reactors decreased from 85% to 65%. The concentration of suspended solids in the effluent could be reduced to 20 mg/l, which corresponded to 7% of that in the influent. The effluent from both reactors was treated aerobically in a fixed-bed reactor. The TOC concentration and optical density of effluent from the aerobic treatment were reduced to 5 mg/l and 0.005, respectively. When the effluent treated anaerobically or aerobically was passed over an activated carbon column, the effluent TOC concentration was reduced to 2 to 3 mg/l. The conductivity in raw wastewater was remarkably reduced on an ion-exchange resin column. Ultra-pure water for industrial ...