An efficient method for computing the absorption of solar radiation by water vapor

Science.gov (United States)

Chou, M.-D.; Arking, A.

1981-01-01

Chou and Arking (1980) have developed a fast but accurate method for computing the IR cooling rate due to water vapor. Using a similar approach, the considered investigation develops a method for computing the heating rates due to the absorption of solar radiation by water vapor in the wavelength range from 4 to 8.3 micrometers. The validity of the method is verified by comparison with line-by-line calculations. An outline is provided of an efficient method for transmittance and flux computations based upon actual line parameters. High speed is achieved by employing a one-parameter scaling approximation to convert an inhomogeneous path into an equivalent homogeneous path at suitably chosen reference conditions.

The role of fragmentation mechanism in large-scale vapor explosions

International Nuclear Information System (INIS)

Liu, Jie

2003-01-01

A non-equilibrium, multi-phase, multi-component code PROVER-I is developed for propagation phase of vapor explosion. Two fragmentation models are used. The hydrodynamic fragmentation model is the same as Fletcher's one. A new thermal fragmentation model is proposed with three kinds of time scale for modeling instant fragmentation, spontaneous nucleation fragmentation and normal boiling fragmentation. The role of fragmentation mechanisms is investigated by the simulations of the pressure wave propagation and energy conversion ratio of ex-vessel vapor explosion. The spontaneous nucleation fragmentation results in a much higher pressure peak and a larger energy conversion ratio than hydrodynamic fragmentation. The instant fragmentation gives a slightly larger energy conversion ratio than spontaneous nucleation fragmentation, and the normal boiling fragmentation results in a smaller energy conversion ratio. The detailed analysis of the structure of pressure wave makes it clear that thermal detonation exists only under the thermal fragmentation circumstance. The high energy conversion ratio is obtained in a small vapor volume fraction. However, in larger vapor volume fraction conditions, the vapor explosion is weak. In a large-scale vapor explosion, the hydrodynamic fragmentation is essential when the pressure wave becomes strong, so a small energy conversion ratio is expected. (author)

Graphene-Based Flexible Micrometer-Sized Microbial Fuel Cell

KAUST Repository

Mink, Justine E.; Qaisi, Ramy M.; Hussain, Muhammad Mustafa

2013-01-01

Microbial fuel cells harvest electrical energy produced by bacteria during the natural decomposition of organic matter. We report a micrometer-sized microbial fuel cell that is able to generate nanowatt-scale power from microliters of liquids

Apparatus and method for removing mercury vapor from a gas stream

Science.gov (United States)

Ganesan, Kumar [Butte, MT

2008-01-01

A metallic filter effectively removes mercury vapor from gas streams. The filter captures the mercury which then can be released and collected as product. The metallic filter is a copper mesh sponge plated with a six micrometer thickness of gold. The filter removes up to 90% of mercury vapor from a mercury contaminated gas stream.

Communication: Surface-facilitated softening of ordinary and vapor-deposited glasses

Science.gov (United States)

Cubeta, Ulyana; Bhattacharya, Deepanjan; Sadtchenko, Vlad

2017-08-01

A common distinction between the ordinary glasses formed by melt cooling and the stable amorphous films formed by vapor deposition is the apparent mechanism of their devitrification. Using quasi-adiabatic, fast scanning calorimetry that is capable of heating rates in excess of 105 K s-1, we have investigated the softening kinetics of micrometer-scale, ordinary glass films of methylbenzene and 2-propanol. At the limit of high heating rates, the transformation mechanism of ordinary glasses is identical to that of their stable vapor-deposited counterparts. In both cases, softening is likely to begin at the sample surface and progress into its bulk via a transformation front. Furthermore, such a surface-facilitated mechanism complies with zero-order, Arrhenius rate law. The activation energy barriers for the softening transformation imply that the kinetics must be defined, at least in part, by the initial thermodynamic and structural state of the samples.

Hygroscopic growth of sub-micrometer and one-micrometer aerosol particles measured during ACE-Asia

Directory of Open Access Journals (Sweden)

A. Massling

2007-06-01

Full Text Available Hygroscopic properties of aerosol particles in the sub-micrometer and one-micrometer size ranges were measured during the ACE-Asia study (Aerosol Characterization Experiment-Asia in spring 2001. The measurements took place off the coasts of Japan, Korea, and China. All instruments contributing to this study were deployed in a container on the forward deck of the NOAA Research Vessel Ronald H. Brown. Air masses with primarily marine influence and air masses from the Asian continent affected by both anthropogenic sources and by the transport of desert dust aerosol were encountered during the cruise.

Results showed very different hygroscopic behavior in the sub-micrometer size range compared to the one-micrometer size range. In general, for all continentally influenced air masses, the one-micrometer particle population was characterized by two different particle groups – a nearly hydrophobic fraction with growth factors around 1.0 representative of dust particles and a sea salt fraction with hygroscopic growth factors around 2.0. The number fraction of dust particles was generally about 60% independent of long-range air mass origin.

For sub-micrometer particles, a dominant, more hygroscopic particle fraction with growth factors between 1.5 and 1.9 (depending on dry particle size consistent with ammonium sulfate or non-neutralized sulfates as major component was always found. In marine air masses and for larger sizes within the sub-micrometer range (Dp=250 and 350 nm, a sea salt fraction with growth factors between 2.0 and 2.1 was also observed. For all other air masses, the more hygroscopic particle fraction in the sub-micrometer size range was mostly accompanied by a less hygroscopic particle fraction with growth factors between 1.20 and 1.55 depending on both the continental sources and the dry particle size. Number fractions of this particle group varied between 4 and 39% depending on dry particle size and air mass

Temperature/pressure and water vapor sounding with microwave spectroscopy

Science.gov (United States)

Muhleman, D. O.; Janssen, M. A.; Clancy, R. T.; Gulkis, S.; Mccleese, D. J.; Zurek, R.; Haberle, R. M.; Frerking, M.

1992-01-01

Two intense microwave spectra lines exist in the martian atmosphere that allow unique sounding capabilities: water vapor at 183 GHz and the (2-1) rotational line of CO at 230 GHz. Microwave spectra line sounding is a well-developed technique for the Earth's atmosphere for sounding from above from spacecraft and airplanes, and from below from fixed surface sites. Two simple instruments for temperature sounding on Mars (the CO line) and water vapor measurements are described. The surface sounder proposed for the MESUR sites is designed to study the boundary layer water vapor distribution and the temperature/pressure profiles with vertical resolution of 0.25 km up to 1 km with reduced resolution above approaching a scale height. The water channel will be sensitive to a few tenths of a micrometer of water and the temperature profile will be retrieved to an accuracy between 1 and 2 K. The latter is routinely done on the Earth using oxygen lines near 60 GHz. The measurements are done with a single-channel heterodyne receiver looking into a 10-cm mirror that is canned through a range of elevation angles plus a target load. The frequency of the receiver is sweep across the water and CO lines generating the two spectra at about 1-hr intervals throughout the mission. The mass and power for the proposed instrument are 2 kg and 5-8 W continuously. The measurements are completely immune to the atmospheric dust and ice particle loads. It was felt that these measurements are the ultimate ones to properly study the martian boundary layer from the surface to a few kilometers. Sounding from above requires an orbiting spacecraft with multichannel microwave spectrometers such as the instrument proposed for MO by a subset of the authors, a putative MESUR orbiter, and a proposed Discovery mission called MOES. Such an instrument can be built with less than 10 kg and use less than 15 W. The obvious advantage of this approach is that the entire atmosphere can be sounded for temperature and

The Annual Cycle of Water Vapor on Mars as Observed by the Thermal Emission Spectrometer

Science.gov (United States)

Smith, Michael D.; Vondrak, Richard R. (Technical Monitor)

2001-01-01

Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water vapor for over one full Martian year (March 1999-March 2001). A maximum in water vapor abundance is observed at high latitudes during mid-summer in both hemispheres, reaching a maximum value of approximately 100 pr-micrometer in the north and approximately 50 pr-micrometer in the south. Low water vapor abundance (water vapor. The latitudinal and seasonal dependence of the decay of the northern summer water vapor maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually-averaged water vapor (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface pressure. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments shows some similar features, but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD and the large latitudinal gradient in annually-averaged water vapor observed by MAWD does not appear in the TES results.

Observation of Mountain Lee Waves with MODIS NIR Column Water Vapor

Science.gov (United States)

Lyapustin, A.; Alexander, M. J.; Ott, L.; Molod, A.; Holben, B.; Susskind, J.; Wang, Y.

2014-01-01

Mountain lee waves have been previously observed in data from the Moderate Resolution Imaging Spectroradiometer (MODIS) "water vapor" 6.7 micrometers channel which has a typical peak sensitivity at 550 hPa in the free troposphere. This paper reports the first observation of mountain waves generated by the Appalachian Mountains in the MODIS total column water vapor (CWV) product derived from near-infrared (NIR) (0.94 micrometers) measurements, which indicate perturbations very close to the surface. The CWV waves are usually observed during spring and late fall or some summer days with low to moderate CWV (below is approx. 2 cm). The observed lee waves display wavelengths from3-4 to 15kmwith an amplitude of variation often comparable to is approx. 50-70% of the total CWV. Since the bulk of atmospheric water vapor is confined to the boundary layer, this indicates that the impact of thesewaves extends deep into the boundary layer, and these may be the lowest level signatures of mountain lee waves presently detected by remote sensing over the land.

Scaling of water vapor in the meso-gamma (2-20km) and lower meso-beta (20-50km) scales from tall tower time series

Science.gov (United States)

Pressel, K. G.; Collins, W.; Desai, A. R.

2011-12-01

Deficiencies in the parameterization of boundary layer clouds in global climate models (GCMs) remains one of the greatest sources of uncertainty in climate change predictions. Many GCM cloud parameterizations, which seek to include some representation of subgrid-scale cloud variability, do so by making assumptions regarding the subgrid-scale spatial probability density function (PDF) of total water content. Properly specifying the form and parameters of the total water PDF is an essential step in the formulation of PDF based cloud parameterizations. In the cloud free boundary layer, the PDF of total water mixing ratio is equivalent to the PDF of water vapor mixing ratio. Understanding the PDF of water vapor mixing ratio in the cloud free atmosphere is a necessary step towards understanding the PDF of water vapor in the cloudy atmosphere. A primary challenge in empirically constraining the PDF of water vapor mixing ratio is a distinct lack of a spatially distributed observational dataset at or near cloud scale. However, at meso-beta (20-50km) and larger scales, there is a wealth of information on the spatial distribution of water vapor contained in the physically retrieved water vapor profiles from the Atmospheric Infrared Sounder onboard NASA`s Aqua satellite. The scaling (scale-invariance) of the observed water vapor field has been suggested as means of using observations at satellite observed (meso-beta) scales to derive information about cloud scale PDFs. However, doing so requires the derivation of a robust climatology of water vapor scaling from in-situ observations across the meso- gamma (2-20km) and meso-beta scales. In this work, we present the results of the scaling of high frequency (10Hz) time series of water vapor mixing ratio as observed from the 447m WLEF tower located near Park Falls, Wisconsin. Observations from a tall tower offer an ideal set of observations with which to investigate scaling at meso-gamma and meso-beta scales requiring only the

Temperature and saturation dependence in the vapor sensing of butterfly wing scales

Energy Technology Data Exchange (ETDEWEB)

Kertész, K., E-mail: kertesz.krisztian@ttk.mta.hu [Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, 1525 Budapest, PO Box 49 (Hungary); Piszter, G. [Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, 1525 Budapest, PO Box 49 (Hungary); Jakab, E. [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, H-1525 Budapest, P O Box 17 (Hungary); Bálint, Zs. [Hungarian Natural History Museum, H-1088, Budapest, Baross utca 13 (Hungary); Vértesy, Z.; Biró, L.P. [Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, 1525 Budapest, PO Box 49 (Hungary)

2014-06-01

The sensing of gasses/vapors in the ambient air is the focus of attention due to the need to monitor our everyday environment. Photonic crystals are sensing materials of the future because of their strong light-manipulating properties. Natural photonic structures are well-suited materials for testing detection principles because they are significantly cheaper than artificial photonic structures and are available in larger sizes. Additionally, natural photonic structures may provide new ideas for developing novel artificial photonic nanoarchitectures with improved properties. In the present paper, we discuss the effects arising from the sensor temperature and the vapor concentration in air during measurements with a photonic crystal-type optical gas sensor. Our results shed light on the sources of discrepancy between simulated and experimental sensing behaviors of photonic crystal-type structures. Through capillary condensation, the vapors will condensate to a liquid state inside the nanocavities. Due to the temperature and radius of curvature dependence of capillary condensation, the measured signals are affected by the sensor temperature as well as by the presence of a nanocavity size distribution. The sensing materials used are natural photonic nanoarchitectures present in the wing scales of blue butterflies. - Highlights: • We report optical gas sensing on blue butterfly wing scale nanostructures. • The sample temperature decrease effects a reversible break-down in the measured spectra. • The break-down is connected with the vapor condensation in the scales and wing surface. • Capillary condensation occurs in the wing scales.

Temperature and saturation dependence in the vapor sensing of butterfly wing scales

International Nuclear Information System (INIS)

Kertész, K.; Piszter, G.; Jakab, E.; Bálint, Zs.; Vértesy, Z.; Biró, L.P.

2014-01-01

The sensing of gasses/vapors in the ambient air is the focus of attention due to the need to monitor our everyday environment. Photonic crystals are sensing materials of the future because of their strong light-manipulating properties. Natural photonic structures are well-suited materials for testing detection principles because they are significantly cheaper than artificial photonic structures and are available in larger sizes. Additionally, natural photonic structures may provide new ideas for developing novel artificial photonic nanoarchitectures with improved properties. In the present paper, we discuss the effects arising from the sensor temperature and the vapor concentration in air during measurements with a photonic crystal-type optical gas sensor. Our results shed light on the sources of discrepancy between simulated and experimental sensing behaviors of photonic crystal-type structures. Through capillary condensation, the vapors will condensate to a liquid state inside the nanocavities. Due to the temperature and radius of curvature dependence of capillary condensation, the measured signals are affected by the sensor temperature as well as by the presence of a nanocavity size distribution. The sensing materials used are natural photonic nanoarchitectures present in the wing scales of blue butterflies. - Highlights: • We report optical gas sensing on blue butterfly wing scale nanostructures. • The sample temperature decrease effects a reversible break-down in the measured spectra. • The break-down is connected with the vapor condensation in the scales and wing surface. • Capillary condensation occurs in the wing scales

Method for Hot Real-Time Analysis of Pyrolysis Vapors at Pilot Scale

Energy Technology Data Exchange (ETDEWEB)

Pomeroy, Marc D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-09-29

Pyrolysis oils contain more than 400 compounds, up to 60% of which do not re-volatilize for subsequent chemical analysis. Vapor chemical composition is also complicated as additional condensation reactions occur during quenching and collection of the product. Due to the complexity of the pyrolysis oil, and a desire to catalytically upgrade the vapor composition before condensation, online real-time analytical techniques such as Molecular Beam Mass Spectrometry (MBMS) are of great use. However, in order to properly sample hot pyrolysis vapors at the pilot scale, many challenges must be overcome.

Detonation and fragmentation modeling for the description of large scale vapor explosions

International Nuclear Information System (INIS)

Buerger, M.; Carachalios, C.; Unger, H.

1985-01-01

The thermal detonation modeling of large-scale vapor explosions is shown to be indispensable for realistic safety evaluations. A steady-state as well as transient detonation model have been developed including detailed descriptions of the dynamics as well as the fragmentation processes inside a detonation wave. Strong restrictions for large-scale vapor explosions are obtained from this modeling and they indicate that the reactor pressure vessel would even withstand explosions with unrealistically high masses of corium involved. The modeling is supported by comparisons with a detonation experiment and - concerning its key part - hydronamic fragmentation experiments. (orig.) [de

Nano-scale topography of bearing surface in advanced alumina/zirconia hip joint before and after severe exposure in water vapor environment.

Science.gov (United States)

Pezzotti, Giuseppe; Saito, Takuma; Padeletti, Giuseppina; Cossari, Pierluigi; Yamamoto, Kengo

2010-06-01

The aim of this study was to perform a surface morphology assessment with nanometer scale resolution on femoral heads made of an advanced zirconia toughened alumina (ZTA) composite. Femoral heads were characterized to a degree of statistical accuracy in the as-received state and after exposures up to 100 h in severe vapor-moist environment. Surface screening was made using an atomic force microscope (AFM). Scanning was systematically repeated on portions of surface as large as several tens of micrometers, randomly selected on the head surface, to achieve sufficient statistical reliability without lowering the nanometer-scale spatial resolution of the roughness measurement. No significant difference was found in the recorded values of surface roughness after environmental exposure (at 134 degrees C, under 2 bar), which was always comparable to that of the as-received head. Surface roughness safely lay <10 nm after environmental exposures up to 100 h, which corresponded to an exposure time in vivo of several human lifetimes (i.e., according to an experimentally derived thermal activation energy). In addition, the roughness results were significantly (about one order of magnitude) lower as compared to those recorded on femoral heads made of monolithic zirconia tested under the same conditions. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Sub-micrometer-scale patterning on Zr-based metallic glass using focused ion beam irradiation and chemical etching

Energy Technology Data Exchange (ETDEWEB)

Kawasegi, Noritaka [Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Morita, Noboru [Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Yamada, Shigeru [Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Takano, Noboru [Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Oyama, Tatsuo [Department of Mechanical and Intellectual Systems Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Ashida, Kiwamu [Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan); Momota, Sadao [Department of Intelligent Mechanical Systems Engineering, Kochi University of Technology, 185 Tosayamada, Kochi 782-8502 (Japan); Taniguchi, Jun [Department of Applied Electronics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Miyamoto, Iwao [Department of Applied Electronics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Ofune, Hitoshi [YKK Corporation, 200 Yoshida, Kurobe, Toyama 938-8601 (Japan)

2007-09-19

This report describes a method of sub-micrometer-scale rapid patterning on a Zr-based metallic glass surface using a combination of focused ion beam irradiation and wet chemical etching. We found that a Zr-based metallic glass surface irradiated with Ga{sup +} ions could be selectively etched; a concave structure with a width and depth of several tens to hundreds of nanometers rapidly formed in the irradiated area. Moreover, we determined that the etching was enhanced by the presence of Ga{sup +} ions rather than a change in the crystal structure, and the structure could be fabricated while the substrate remained amorphous. The shape of the structure was principally a function of the dose and the etch time.

DNA damage on nano- and micrometer scales impacts dicentric induction: computer modelling of ion microbeam experiments

Science.gov (United States)

Friedland, Werner; Kundrat, Pavel; Schmitt, Elke

2016-07-01

Detailed understanding of the enhanced relative biological effectiveness (RBE) of ions, in particular at high linear energy transfer (LET) values, is needed to fully explore the radiation risk of manned space missions. It is generally accepted that the enhanced RBE of high-LET particles results from the DNA lesion patterns, in particular DNA double-strand breaks (DSB), due to the spatial clustering of energy deposits around their trajectories. In conventional experiments on biological effects of radiation types of diverse quality, however, clustering of energy deposition events on nanometer scale that is relevant for the induction and local complexity of DSB is inherently interlinked with regional (sub-)micrometer-scale DSB clustering along the particle tracks. Due to this limitation, the role of both (nano- and micrometer) scales on the induction of diverse biological endpoints cannot be frankly separated. To address this issue in a unique way, experiments at the ion microbeam SNAKE [1] and corresponding track-structure based model calculations of DSB induction and subsequent repair with the biophysical code PARTRAC [2] have been performed. In the experiments, hybrid human-hamster A_{L} cells were irradiated with 20 MeV (2.6 keV/μm) protons, 45 MeV (60 keV/μm) lithium ions or 55 MeV (310 keV/μm) carbon ions. The ions were either quasi-homogeneously distributed or focused to 0.5 x 1 μm^{2} spots on regular matrix patterns of 5.4 μm, 7.6 μm and 10.6 μm grid size, with pre-defined particle numbers per spot so as to deposit a mean dose of 1.7 Gy for all irradiation patterns. As expected, the induction of dicentrics by homogeneous irradiation increased with LET: lithium and carbon ions induced about two- and four-fold higher yields of dicentrics than protons. The induction of dicentrics is, however, affected by µm-scale, too: focusing 20 lithium ions or 451 protons per spot on a 10.6 μm grid induced two or three times more dicentrics, respectively, than a

Moulding of Sub-micrometer Surface Structures

DEFF Research Database (Denmark)

Pranov, Henrik; Rasmussen, Henrik K.; Larsen, Niels Bent

2006-01-01

The experiments strongly suggest that the possibility to injection mould sub-micrometer surface structures in polymers mainly relates to the forces originating from the adhesive energy between polymer and shim.......The experiments strongly suggest that the possibility to injection mould sub-micrometer surface structures in polymers mainly relates to the forces originating from the adhesive energy between polymer and shim....

Continuous Water Vapor Mass Flux and Temperature Measurements in a Model Scramjet Combustor Using a Diode Laser Sensor

National Research Council Canada - National Science Library

Upschulte, B. L; Miller, M. F; Allen, M. G; Jackson, K; Gruber, M; Mathur, T

1998-01-01

A sensor for simultaneous measurements of water vapor density, temperature and velocity has been developed based on absorption techniques using room temperature diode lasers (InGaAsP) operating at 1.31 micrometers...

Vapor Grown Carbon Fiber/Polydicyclopentadiene Composites: Shapeable Pastes to Make Composite Tooling and Plasma Erosion-Resistant Parts

National Research Council Canada - National Science Library

Pittman, Charles

2002-01-01

Vapor grown carbon nanofibers (VGCF) with 60-250nm diameters and 10 to 80 micrometers lengths were blended with the nonpolar organic monomer, dicyclopentadiene, to create liquid dispersions or pastes (based on the wt% fiber used...

Effect of the small accessary laser spots on the harmonic emission stimulated by self-focusing of a 10-micrometer scale laser spot

International Nuclear Information System (INIS)

Lin Zunqi; Zhang Huihuang; He Xingfa

1992-01-01

A novel group of experiments has shown that single 10-micrometer-radius-scale laser spot is not able to produce the 90 deg side emitted three half harmonic efficiently in a preformed laser plasmas. However, with the help of one or two accessory laser spots with the size similar to the main one, the side emitted three half can easily built up when some position and angle conditions for the accessory spots are fulfilled. The origin of these phenomena have been analyzed in terms of the two plasmon decay theory and dynamic self-focusing model

Laser pulse propagation in a meter scale rubidium vapor/plasma cell in AWAKE experiment

Energy Technology Data Exchange (ETDEWEB)

Joulaei, A. [Max-Planck Institute for Physics, Munich (Germany); University of Mazandaran (Iran, Islamic Republic of); Moody, J. [Max-Planck Institute for Physics, Munich (Germany); Berti, N.; Kasparian, J. [University of Geneva (Switzerland); Mirzanejhad, S. [University of Mazandaran (Iran, Islamic Republic of); Muggli, P. [Max-Planck Institute for Physics, Munich (Germany)

2016-09-01

We present the results of numerical studies of laser pulse propagating in a 3.5 cm Rb vapor cell in the linear dispersion regime by using a 1D model and a 2D code that has been modified for our special case. The 2D simulation finally aimed at finding laser beam parameters suitable to make the Rb vapor fully ionized to obtain a uniform, 10 m-long, at least 1 mm in radius plasma in the next step for the AWAKE experiment. - Highlights: • Discussion the AWAKE plasma source based on photoionization of rubidium vapor with a TW/cm^2 Intensity laser with a spectrum across valence ground state transition resonances. • Examines the propagation of the AWAKE ionization laser through rubidium vapor at design density on a small scale and reduced intensity with a linear numerical model compared to experimental results. • Discusses physics of pulse propagation through the vapor at high intensity regime where strong ionization occurs within the laser pulse.

Large Scale Water Vapor Sources Relative to the October 2000 Piedmont Flood

Science.gov (United States)

Turato, Barbara; Reale, Oreste; Siccardi, Franco

2003-01-01

Very intense mesoscale or synoptic-scale rainfall events can occasionally be observed in the Mediterranean region without any deep cyclone developing over the areas affected by precipitation. In these perplexing cases the synoptic situation can superficially look similar to cases in which very little precipitation occurs. These situations could possibly baffle the operational weather forecasters. In this article, the major precipitation event that affected Piedmont (Italy) between 13 and 16 October 2000 is investigated. This is one of the cases in which no intense cyclone was observed within the Mediterranean region at any time, only a moderate system was present, and yet exceptional rainfall and flooding occurred. The emphasis of this study is on the moisture origin and transport. Moisture and energy balances are computed on different space- and time-scales, revealing that precipitation exceeds evaporation over an area inclusive of Piedmont and the northwestern Mediterranean region, on a time-scale encompassing the event and about two weeks preceding it. This is suggestive of an important moisture contribution originating from outside the region. A synoptic and dynamic analysis is then performed to outline the potential mechanisms that could have contributed to the large-scale moisture transport. The central part of the work uses a quasi-isentropic water-vapor back trajectory technique. The moisture sources obtained by this technique are compared with the results of the balances and with the synoptic situation, to unveil possible dynamic mechanisms and physical processes involved. It is found that moisture sources on a variety of atmospheric scales contribute to this event. First, an important contribution is caused by the extratropical remnants of former tropical storm Leslie. The large-scale environment related to this system allows a significant amount of moisture to be carried towards Europe. This happens on a time- scale of about 5-15 days preceding the

Development of Kossel micro-diffraction for strain and stress analysis at the micrometer scale: applications to crystalline materials

International Nuclear Information System (INIS)

Bouscaud, D.

2012-01-01

X-ray diffraction is a non-destructive method frequently used in materials science to analyse the stress state at a macroscopic scale. Due to the growing complexity of new materials and their applications, it is necessary to know the strain and stress state at a lower scale. Thus, a Kossel micro-diffraction experimental set-up was developed inside a scanning electron microscope. It allows to obtain the crystallographic orientation as well as the strains and stresses within a volume of a few cubic micrometers. Some experiments were also performed using a synchrotron radiation. An experimental procedure was developed to optimize the acquisition of Kossel line patterns and their post-processing. The stress calculation from Kossel patterns was validated by comparing the stress state of single crystals during in situ mechanical loading, obtained by Kossel micro-diffraction and with classical diffraction methods. Then Kossel micro-diffraction was applied to polycrystalline samples by gradually decreasing the grain size. Intergranular stress heterogeneities were for example measured in an interstitial-free steel. Experiments were finally carried out in thin layer samples representative of microelectronic components. (author)

The Design of Phase-Locked-Loop Circuit for Precision Capacitance Micrometer

Directory of Open Access Journals (Sweden)

Li Shujie

2016-01-01

Full Text Available High precision non-contact micrometer is normally divided into three categories: inductance micrometer, capacitance micrometer and optical interferometer micrometer. The capacitance micrometer is widely used because it has high performance to price ratio. With the improvement of automation level, precision of capacitance micrometer is required higher and higher. Generally, capacitance micrometer consists of the capacitance sensor, capacitance/voltage conversion circuit, and modulation and demodulation circuits. However, due to the existing of resistors, capacitors and other components in the circuit, the phase shift of the carrier signal and the modulated signal might occur. In this case, the specific value of phase shift cannot be determined. Therefore, error caused by the phase shift cannot be eliminated. This will reduce the accuracy of micrometer. In this design, in order to eliminate the impact of the phase shift, the phase-locked-loop (PLL circuit is employed. Through the experiment, the function of tracking the input signal phase and frequency is achieved by the phase-locked-loop circuit. This signal processing method can also be applied to tuber electrical resistance tomography system and other precision measurement circuit.

Wafer-scale synthesis of monolayer and few-layer MoS2 via thermal vapor sulfurization

Science.gov (United States)

Robertson, John; Liu, Xue; Yue, Chunlei; Escarra, Matthew; Wei, Jiang

2017-12-01

Monolayer molybdenum disulfide (MoS2) is an atomically thin, direct bandgap semiconductor crystal potentially capable of miniaturizing optoelectronic devices to an atomic scale. However, the development of 2D MoS2-based optoelectronic devices depends upon the existence of a high optical quality and large-area monolayer MoS2 synthesis technique. To address this need, we present a thermal vapor sulfurization (TVS) technique that uses powder MoS2 as a sulfur vapor source. The technique reduces and stabilizes the flow of sulfur vapor, enabling monolayer wafer-scale MoS2 growth. MoS2 thickness is also controlled with great precision; we demonstrate the ability to synthesize MoS2 sheets between 1 and 4 layers thick, while also showing the ability to create films with average thickness intermediate between integer layer numbers. The films exhibit wafer-scale coverage and uniformity, with electrical quality varying depending on the final thickness of the grown MoS2. The direct bandgap of grown monolayer MoS2 is analyzed using internal and external photoluminescence quantum efficiency. The photoluminescence quantum efficiency is shown to be competitive with untreated exfoliated MoS2 monolayer crystals. The ability to consistently grow wafer-scale monolayer MoS2 with high optical quality makes this technique a valuable tool for the development of 2D optoelectronic devices such as photovoltaics, detectors, and light emitters.

Fabrication of Micrometer- and Nanometer-Scale Polymer Structures by Visible Light Induced Dielectrophoresis (DEP Force

Directory of Open Access Journals (Sweden)

Wen J. Li

2011-12-01

Full Text Available We report in this paper a novel, inexpensive and flexible method for fabricating micrometer- and nanometer-scale three-dimensional (3D polymer structures using visible light sources instead of ultra-violet (UV light sources or lasers. This method also does not require the conventional micro-photolithographic technique (i.e., photolithographic masks for patterning and fabricating polymer structures such as hydrogels. The major materials and methods required for this novel fabrication technology are: (1 any cross-linked network of photoactive polymers (examples of fabricated poly(ethylene glycol (PEG-diacrylate hydrogel structures are shown in this paper; (2 an Optically-induced Dielectrophoresis (ODEP System which includes an “ODEP chip” (i.e., any chip that changes its surface conductivity when exposed to visible light, an optical microscope, a projector, and a computer; and (3 an animator software hosted on a computer that can generate virtual or dynamic patterns which can be projected onto the “ODEP chip” through the use of a projector and a condenser lens. Essentially, by placing a photosensitive polymer solution inside the microfluidic platform formed by the “ODEP chip” bonded to another substrate, and applying an alternating current (a.c. electrical potential across the polymer solution (typically ~20 Vp-p at 10 kHz, solid polymer micro/nano structures can then be formed on the “ODEP chip” surface when visible-light is projected onto the chip. The 2D lateral geometry (x and y dimensions and the thickness (height of the micro/nano structures are dictated by the image geometry of the visible light projected onto the “ODEP chip” and also the time duration of projection. Typically, after an image projection with intensity ranging from ~0.2 to 0.4 mW/cm2 for 10 s, ~200 nm high structures can be formed. In our current system, the thickness of these polymer structures can be controlled to form from ~200 nanometers to ~3

Atmospheric-water absorption features near 2.2 micrometers and their importance in high spectral resolution remote sensing

Science.gov (United States)

Kruse, F. A.; Clark, R. N.

1986-01-01

Selective absorption of electromagnetic radiation by atmospheric gases and water vapor is an accepted fact in terrestrial remote sensing. Until recently, only a general knowledge of atmospheric effects was required for analysis of remote sensing data; however, with the advent of high spectral resolution imaging devices, detailed knowledge of atmospheric absorption bands has become increasingly important for accurate analysis. Detailed study of high spectral resolution aircraft data at the U.S. Geological Survey has disclosed narrow absorption features centered at approximately 2.17 and 2.20 micrometers not caused by surface mineralogy. Published atmospheric transmission spectra and atmospheric spectra derived using the LOWTRAN-5 computer model indicate that these absorption features are probably water vapor. Spectral modeling indicates that the effects of atmospheric absorption in this region are most pronounced in spectrally flat materials with only weak absorption bands. Without correction and detailed knowledge of the atmospheric effects, accurate mapping of surface mineralogy (particularly at low mineral concentrations) is not possible.

Fabrication of yttrium-doped barium zirconate thin films with sub-micrometer thickness by a sol–gel spin coating method

Energy Technology Data Exchange (ETDEWEB)

Xie, Hanlin; Su, Pei-Chen, E-mail: peichensu@ntu.edu.sg

2015-06-01

A modified sol–gel process was developed for the fabrication of sub-micrometer scale yttrium-doped barium zirconate (BZY) thin film at much lower processing temperatures. The film was fabricated by direct spin-coating of the sol on a Si{sub 3}N{sub 4} passivated Si substrate, followed by low temperature thermal annealing at 1000 °C, and single BZY phase without barium carbonate residue was obtained. A 200 nm-thick thin film without obvious through-film cracks was fabricated with optimized process parameters of sol concentration and heating rate. The stoichiometry of the BZY thin film was well-controlled and no Ba evaporation was observed due to the low processing temperature. The combination of sol–gel and spin coating method can be a promising alternative to vacuum-based thin film deposition techniques for the fabrication of sub-micrometer scale BZY thin film. - Highlights: • A sol–gel spin coating method was developed for the fabrication of BZY thin films. • The processing temperature was much lower compared to powder-based sintering. • Sub-micrometer scale BZY thin film with well-controlled stoichiometry was obtained.

Growth behavior of LiMn2O4 particles formed by solid-state reactions in air and water vapor

International Nuclear Information System (INIS)

Kozawa, Takahiro; Yanagisawa, Kazumichi; Murakami, Takeshi; Naito, Makio

2016-01-01

Morphology control of particles formed during conventional solid-state reactions without any additives is a challenging task. Here, we propose a new strategy to control the morphology of LiMn 2 O 4 particles based on water vapor-induced growth of particles during solid-state reactions. We have investigated the synthesis and microstructural evolution of LiMn 2 O 4 particles in air and water vapor atmospheres as model reactions; LiMn 2 O 4 is used as a low-cost cathode material for lithium-ion batteries. By using spherical MnCO 3 precursor impregnated with LiOH, LiMn 2 O 4 spheres with a hollow structure were obtained in air, while angulated particles with micrometer sizes were formed in water vapor. The pore structure of the particles synthesized in water vapor was found to be affected at temperatures below 700 °C. We also show that the solid-state reaction in water vapor is a simple and valuable method for the large-scale production of particles, where the shape, size, and microstructure can be controlled. - Graphical abstract: This study has demonstrated a new strategy towards achieving morphology control without the use of additives during conventional solid-state reactions by exploiting water vapor-induced particle growth. - Highlights: • A new strategy to control the morphology of LiMn 2 O 4 particles is proposed. • Water vapor-induced particle growth is exploited in solid-state reactions. • The microstructural evolution of LiMn 2 O 4 particles is investigated. • The shape, size and microstructure can be controlled by solid-state reactions.

Effect of water vapor on annealing scale formation on 316 SS

International Nuclear Information System (INIS)

Cheng, S.-Y.; Kuan, S.-L.; Tsai, W.-T.

2006-01-01

The oxidation behavior of 316 stainless steel (SS) annealed in air containing 0.1 atm water vapor at temperatures ranging from 800 to 1030 deg. C was investigated. A kinetic study of the oxidation was made by employing thermal-gravimetric analysis (TGA). The morphology, composition and structure of the scale were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental results showed that significant breakaway oxidation occurred, resulting in substantial weight increase, as the steel was annealed in moist air at temperatures above 950 deg. C. The scaling behavior of 316 SS in wet air at 1030 deg. C could be divided into two stages based on the alteration of the oxidation rate. In each stage, the scale on 316 SS exhibited a different structure and morphology. The complex process of the formation of scale in wet air was discussed and proposed

Large-scale, rapid synthesis and application in surface-enhanced Raman spectroscopy of sub-micrometer polyhedral gold nanocrystals

International Nuclear Information System (INIS)

Guo Shaojun; Wang Yuling; Wang Erkang

2007-01-01

Macromolecule-protected sub-micrometer polyhedral gold nanocrystals have been facilely prepared by heating an aqueous solution containing poly (N-vinyl-2-pyrrolidone) (PVP) and HAuCl 4 without adding other reducing agents. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), ultraviolet-visible-near-infrared spectroscopy (UV-vis-NIR), and x-ray diffraction (XRD) were employed to characterize the obtained polyhedral gold nanocrystals. It is found that the 10:1 molar ratio of PVP to gold is a key factor for obtaining quasi-monodisperse polyhedral gold nanocrystals. Furthermore, the application of polyhedral gold nanocrystals in surface-enhanced Raman scattering (SERS) was investigated by using 4-aminothiophenol (4-ATP) as a probe molecule. The results indicated that the sub-micrometer polyhedral gold nanocrystals modified on the ITO substrate exhibited higher SERS activity compared to the traditional gold nanoparticle modified film. The enhancement factor (EF) on polyhedral gold nanocrystals was about six times larger than that obtained on aggregated gold nanoparticles (∼25 nm)

Microspectroscopic imaging of solution plasma: How do its physical properties and chemical species evolve in atmospheric-pressure water vapor bubbles?

Science.gov (United States)

Yui, Hiroharu; Banno, Motohiro

2018-01-01

In this article, we review the development of scientific instruments for obtaining information on the evolution of physical properties and chemical species of solution plasma (SP). When a pulsed high voltage is applied between electrodes immersed in an aqueous solution, SP is formed in water vapor bubbles transiently generated in the solution under atmospheric pressure. To clarify how SP emerges in water vapor bubbles and is sustained in solutions, an instrument with micrometer spatial resolution and nanosecond temporal resolution is required. To meet these requirements, a microscopic system with a custom-made optical discharge cell was newly developed, where the working distance between the SP and the microscopic objective lens was minimized. A hollow electrode equipped in the discharge cell also enabled us to control the chemical composition in water vapor bubbles. To study the spatial and temporal evolutions of chemical species in micrometer and nano- to microsecond regions, a streak camera with a spectrometer and a CCD detector with a time-gated electronic device were combined with the microscope system. The developed instrument is expected to contribute to providing a new means of developing new schemes for chemical reactions and material syntheses.

Modeling Transport of Cesium in Grimsel Granodiorite With Micrometer Scale Heterogeneities and Dynamic Update of Kd

Science.gov (United States)

Voutilainen, Mikko; Kekäläinen, Pekka; Siitari-Kauppi, Marja; Sardini, Paul; Muuri, Eveliina; Timonen, Jussi; Martin, Andrew

2017-11-01

Transport and retardation of cesium in Grimsel granodiorite taking into account heterogeneity of mineral and pore structure was studied using rock samples overcored from an in situ diffusion test at the Grimsel Test Site. The field test was part of the Long-Term Diffusion (LTD) project designed to characterize retardation properties (diffusion and distribution coefficients) under in situ conditions. Results of the LTD experiment for cesium showed that in-diffusion profiles and spatial concentration distributions were strongly influenced by the heterogeneous pore structure and mineral distribution. In order to study the effect of heterogeneity on the in-diffusion profile and spatial concentration distribution, a Time Domain Random Walk (TDRW) method was applied along with a feature for modeling chemical sorption in geological materials. A heterogeneous mineral structure of Grimsel granodiorite was constructed using X-ray microcomputed tomography (X-μCT) and the map was linked to previous results for mineral specific porosities and distribution coefficients (Kd) that were determined using C-14-PMMA autoradiography and batch sorption experiments, respectively. After this the heterogeneous structure contains information on local porosity and Kd in 3-D. It was found that the heterogeneity of the mineral structure on the micrometer scale affects significantly the diffusion and sorption of cesium in Grimsel granodiorite at the centimeter scale. Furthermore, the modeled in-diffusion profiles and spatial concentration distributions show similar shape and pattern to those from the LTD experiment. It was concluded that the use of detailed structure characterization and quantitative data on heterogeneity can significantly improve the interpretation and evaluation of transport experiments.

Comparison of the 3.36 micrometer feature to the ISM

International Nuclear Information System (INIS)

Tokunaga, A.T.; Brooke, T.Y.

1988-01-01

It has been noted that the 3.36 micrometer emission feature is not the same as that of any ISM band at 3.4 micrometer. This is documented herein. There is no convincing analog to the cometary 3.36 micrometer emission feature seen in the Interstellar Matter band. This fact suggests that if the carbonaceous material in comets came from the ISM, it was either further processed in the solar nebula or has a different appearance because of the different excitation environment of the sun and ISM

Comparison of the 3.36 micrometer feature to the ISM

Science.gov (United States)

Tokunaga, Alan T.; Brooke, Timothy Y.

1988-01-01

It has been noted that the 3.36 micrometer emission feature is not the same as that of any ISM band at 3.4 micrometer. This is documented herein. There is no convincing analog to the cometary 3.36 micrometer emission feature seen in the Interstellar Matter band. This fact suggests that if the carbonaceous material in comets came from the ISM, it was either further processed in the solar nebula or has a different appearance because of the different excitation environment of the sun and ISM.

Lab-scale tests on ISV vapor transport phenomena

International Nuclear Information System (INIS)

Farnsworth, R.K.; Gardner, B.M.

1996-01-01

In situ vitrification (ISV) is a promising technology for remediating buried waste sites and contaminated soil sites. However, concerns exist that low soil permeabilities may limit vapor transport away from the advancing melt front and cause a melt expulsion that breaches ISV containment. As a result, two ISV lab tests were conducted at the Idaho National Engineering Laboratory (INEL) using INEL soil (permeability: 10 -6 cm/s) and a low permeability (10 -10 cm/s) clay material. The clay test also had a ceramic tube inserted vertically through the center of the area being melted to provide one-dimensional data on vapor transport. Results confirm that low soil permeabilities can limit vapor transport away from the advancing ISV melt front. In addition, peak pressures inside the ceramic tube were significantly greater than those outside the tube, indicating the importance of horizontal vapor transport around the advancing ISV melt front

Small-scale experimental study of vaporization flux of liquid nitrogen released on water.

Science.gov (United States)

Gopalaswami, Nirupama; Olewski, Tomasz; Véchot, Luc N; Mannan, M Sam

2015-10-30

A small-scale experimental study was conducted using liquid nitrogen to investigate the convective heat transfer behavior of cryogenic liquids released on water. The experiment was performed by spilling five different amounts of liquid nitrogen at different release rates and initial water temperatures. The vaporization mass fluxes of liquid nitrogen were determined directly from the mass loss measured during the experiment. A variation of initial vaporization fluxes and a subsequent shift in heat transfer mechanism were observed with changes in initial water temperature. The initial vaporization fluxes were directly dependent on the liquid nitrogen spill rate. The heat flux from water to liquid nitrogen determined from experimental data was validated with two theoretical correlations for convective boiling. It was also observed from validation with correlations that liquid nitrogen was found to be predominantly in the film boiling regime. The substantial results provide a suitable procedure for predicting the heat flux from water to cryogenic liquids that is required for source term modeling. Copyright © 2015 Elsevier B.V. All rights reserved.

Growth behavior of LiMn{sub 2}O{sub 4} particles formed by solid-state reactions in air and water vapor

Energy Technology Data Exchange (ETDEWEB)

Kozawa, Takahiro, E-mail: t-kozawa@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11–1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Yanagisawa, Kazumichi [Research Laboratory of Hydrothermal Chemistry, Faculty of Science, Kochi University, 2–5-1 Akebono-cho, Kochi 780-8520 (Japan); Murakami, Takeshi; Naito, Makio [Joining and Welding Research Institute, Osaka University, 11–1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

2016-11-15

Morphology control of particles formed during conventional solid-state reactions without any additives is a challenging task. Here, we propose a new strategy to control the morphology of LiMn{sub 2}O{sub 4} particles based on water vapor-induced growth of particles during solid-state reactions. We have investigated the synthesis and microstructural evolution of LiMn{sub 2}O{sub 4} particles in air and water vapor atmospheres as model reactions; LiMn{sub 2}O{sub 4} is used as a low-cost cathode material for lithium-ion batteries. By using spherical MnCO{sub 3} precursor impregnated with LiOH, LiMn{sub 2}O{sub 4} spheres with a hollow structure were obtained in air, while angulated particles with micrometer sizes were formed in water vapor. The pore structure of the particles synthesized in water vapor was found to be affected at temperatures below 700 °C. We also show that the solid-state reaction in water vapor is a simple and valuable method for the large-scale production of particles, where the shape, size, and microstructure can be controlled. - Graphical abstract: This study has demonstrated a new strategy towards achieving morphology control without the use of additives during conventional solid-state reactions by exploiting water vapor-induced particle growth. - Highlights: • A new strategy to control the morphology of LiMn{sub 2}O{sub 4} particles is proposed. • Water vapor-induced particle growth is exploited in solid-state reactions. • The microstructural evolution of LiMn{sub 2}O{sub 4} particles is investigated. • The shape, size and microstructure can be controlled by solid-state reactions.

Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD

Energy Technology Data Exchange (ETDEWEB)

Soria, José, E-mail: jose.soria@probien.gob.ar [Institute for Research and Development in Process Engineering, Biotechnology and Alternative Energies (PROBIEN, CONICET – UNCo), 1400 Buenos Aires St., 8300 Neuquén (Argentina); Gauthier, Daniel; Flamant, Gilles [Processes, Materials and Solar Energy Laboratory (PROMES-CNRS, UPR 8521), 7 Four Solaire Street, Odeillo, 66120 Font-Romeu (France); Rodriguez, Rosa [Chemical Engineering Institute, National University of San Juan, 1109 Libertador (O) Avenue, 5400 San Juan (Argentina); Mazza, Germán [Institute for Research and Development in Process Engineering, Biotechnology and Alternative Energies (PROBIEN, CONICET – UNCo), 1400 Buenos Aires St., 8300 Neuquén (Argentina)

2015-09-15

Highlights: • A CFD two-scale model is formulated to simulate heavy metal vaporization from waste incineration in fluidized beds. • MSW particle is modelled with the macroscopic particle model. • Influence of bed dynamics on HM vaporization is included. • CFD predicted results agree well with experimental data reported in literature. • This approach may be helpful for fluidized bed reactor modelling purposes. - Abstract: Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073 K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator.

Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD

International Nuclear Information System (INIS)

Soria, José; Gauthier, Daniel; Flamant, Gilles; Rodriguez, Rosa; Mazza, Germán

2015-01-01

Highlights: • A CFD two-scale model is formulated to simulate heavy metal vaporization from waste incineration in fluidized beds. • MSW particle is modelled with the macroscopic particle model. • Influence of bed dynamics on HM vaporization is included. • CFD predicted results agree well with experimental data reported in literature. • This approach may be helpful for fluidized bed reactor modelling purposes. - Abstract: Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073 K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator

Sub-micrometer waveguide for nano-optics

DEFF Research Database (Denmark)

Rottwitt, Karsten; Dyndgaard, Morten Glarborg; Andersen, Karin Nordström

2003-01-01

With the recent progress within the field of processing nano structures, there is an increasing interest in coupling light into such structures both for characterization of optical properties and new optical components. In this work we propose the use of a sub-micrometer planar waveguide for prob......With the recent progress within the field of processing nano structures, there is an increasing interest in coupling light into such structures both for characterization of optical properties and new optical components. In this work we propose the use of a sub-micrometer planar waveguide...... for probing the reflection of light against a nano structure. The planar waveguide is based on a silicon nitride core layer, surrounded by a silica cladding region. In our design we utilize this waveguide to couple light into a nano-structure....

Multi-scale organization of water vapor over low and mid-tropical Africa

CSIR Research Space (South Africa)

Botai, OJ

2009-01-01

Full Text Available stream_source_info Botai_2009.pdf.txt stream_content_type text/plain stream_size 23192 Content-Encoding UTF-8 stream_name Botai_2009.pdf.txt Content-Type text/plain; charset=UTF-8 1 MULTI-SCALE ORGANIZATION OF WATER.... Integrated water vapor field and multiscale variations over China from GPS measurements. J. appl., Meteo., Climatol., 47, pp. 3008-3015 8. Johnsen K. P., 2003. GPS atmosphere sounding project- An innovative approach for the recovery of atmospheric...

Synthesis and characterization of micrometer Cu/PVP architectures

International Nuclear Information System (INIS)

Luo, Huajuan; Zhao, Yanbao; Sun, Lei

2011-01-01

Graphical abstract: A simple method for the synthesis of novel micrometer flower-like Cu/PVP architectures was introduced. Highlights: → Micrometer flower-like copper/polyvinylpyrrolidone architectures were obtained by a simple chemical route. → The amount of N 2 H 4 ·H 2 O, the reaction temperature, the molar ratio of CuCl 2 to PVP and different molecular weights of PVP play an important role in the controlling the morphology of the Cu/PVP architectures. → A possible mechanism of the formation of Cu/PVP architectures was discussed. -- Abstract: Micrometer-sized flower-like Cu/polyvinylpyrrolidone (PVP) architectures are synthesized by the reduction of copper (II) salt with hydrazine hydrate in aqueous solution in the presence of PVP capping agent. The resulting Cu/PVP architectures are investigated by UV-vis spectroscopy, transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The Cu/PVP flowers have uniform morphologies with an average diameter of 10 μm, made of several intercrossing plates. The formation of Cu/PVP flowers is a new kinetic control process, and the factors such as the amount of N 2 H 4 ·H 2 O, reaction temperature, molar ratio of CuCl 2 to PVP and molecular weight of PVP have significant effect on the morphology of Cu/PVP architectures. A possible mechanism of the formation of micrometer Cu/PVP architectures was discussed.

Focusing of sub-micrometer particles and bacteria enabled by two-dimensional acoustophoresis

DEFF Research Database (Denmark)

Antfolk, M.; Muller, Peter Barkholt; Augustsson, P.

2014-01-01

Handling of sub-micrometer bioparticles such as bacteria are becoming increasingly important in the biomedical field and in environmental and food analysis. As a result, there is an increased need for less labor-intensive and time-consuming handling methods. Here, an acoustophoresis-based microfl......Handling of sub-micrometer bioparticles such as bacteria are becoming increasingly important in the biomedical field and in environmental and food analysis. As a result, there is an increased need for less labor-intensive and time-consuming handling methods. Here, an acoustophoresis......-based microfluidic chip that uses ultrasound to focus sub-micrometer particles and bacteria, is presented. The ability to focus sub-micrometer bioparticles in a standing one-dimensional acoustic wave is generally limited by the acoustic-streaming-induced drag force, which becomes increasingly significant the smaller...... particles as small as 0.5 μm in diameter in microchannels of square or rectangular cross sections, is demonstrated. Numerical analysis was used to determine generic transverse particle trajectories in the channels, which revealed spiral-shaped trajectories of the sub-micrometer particles towards the center...

Final report on the small-scale vapor-explosion experiments using a molten NaCl--H2O system

International Nuclear Information System (INIS)

Anderson, R.P.; Bova, L.

1976-04-01

Vapor explosions were produced by injecting small quantities of water into a container filled with molten NaCl. Minimum explosion efficiencies, as evaluated from reaction-impulse measurements, were relatively large. Subsurface movies showed that the explosions resulted from a two-step sequence: an initial bulk-mixing phase in which the two liquids intermix on a large scale, but remain locally separated by an insulating gas-vapor layer; and a second step, immediately following breakdown of the gas layer, during which the two liquids locally fragment, intermix, and pressurize very rapidly. The experimental results were compared with various mechanistic models that had been proposed to explain vapor explosions. Early models seemed inconsistent with the results. More recent theories suggest that vapor explosions may be caused by a nucleation limit or by dynamic mixing combined with high surface-heat-transfer rates. Both types of models are consistent with the results

Large scale graphene/hexagonal boron nitride heterostructure for tunable plasmonics

KAUST Repository

Zhang, Kai

2013-09-01

Vertical integration of hexagonal boron nitride (h-BN) and graphene for the fabrication of vertical field-effect transistors or tunneling diodes has stimulated intense interest recently due to the enhanced performance offered by combining an ultrathin dielectric with a semi-metallic system. Wafer scale fabrication and processing of these heterostructures is needed to make large scale integrated circuitry. In this work, by using remote discharged, radio-frequency plasma chemical vapor deposition, wafer scale, high quality few layer h-BN films are successfully grown. By using few layer h-BN films as top gate dielectric material, the plasmon energy of graphene can be tuned by electrostatic doping. An array of graphene/h-BN vertically stacked micrometer-sized disks is fabricated by lithography and transfer techniques, and infrared spectroscopy is used to observe the modes of tunable graphene plasmonic absorption as a function of the repeating (G/h-BN)n units in the vertical stack. Interestingly, the plasmonic resonances can be tuned to higher frequencies with increasing layer thickness of the disks, showing that such vertical stacking provides a viable strategy to provide wide window tuning of the plasmons beyond the limitation of the monolayer. An array of graphene/h-BN vertically stacked micrometer-sized disks is fabricated by lithography and transfer techniques, and infrared spectroscopy is used to observe the modes of tunable graphene plasmonic absorption as a function of the repeating (G/h-BN)n units in the vertical stack. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Agonist-induced PIP(2) hydrolysis inhibits cortical actin dynamics: regulation at a global but not at a micrometer scale.

Science.gov (United States)

van Rheenen, Jacco; Jalink, Kees

2002-09-01

Phosphatidylinositol 4, 5-bisphosphate (PIP(2)) at the inner leaflet of the plasma membrane has been proposed to locally regulate the actin cytoskeleton. Indeed, recent studies that use GFP-tagged pleckstrin homology domains (GFP-PH) as fluorescent PIP(2) sensors suggest that this lipid is enriched in membrane microdomains. Here we report that this concept needs revision. Using three distinct fluorescent GFP-tagged pleckstrin homology domains, we show that highly mobile GFP-PH patches colocalize perfectly with various lipophilic membrane dyes and, hence, represent increased lipid content rather than PIP(2)-enriched microdomains. We show that bright patches are caused by submicroscopical folds and ruffles in the membrane that can be directly visualized at approximately 15 nm axial resolution with a novel numerically enhanced imaging method. F-actin motility is inhibited significantly by agonist-induced PIP(2) breakdown, and it resumes as soon as PIP(2) levels are back to normal. Thus, our data support a role for PIP(2) in the regulation of cortical actin, but they challenge a model in which spatial differences in PIP(2) regulation of the cytoskeleton exist at a micrometer scale.

Experimental study of detonation of large-scale powder-droplet-vapor mixtures

Science.gov (United States)

Bai, C.-H.; Wang, Y.; Xue, K.; Wang, L.-F.

2018-05-01

Large-scale experiments were carried out to investigate the detonation performance of a 1600-m3 ternary cloud consisting of aluminum powder, fuel droplets, and vapor, which were dispersed by a central explosive in a cylindrically stratified configuration. High-frame-rate video cameras and pressure gauges were used to analyze the large-scale explosive dispersal of the mixture and the ensuing blast wave generated by the detonation of the cloud. Special attention was focused on the effect of the descending motion of the charge on the detonation performance of the dispersed ternary cloud. The charge was parachuted by an ensemble of apparatus from the designated height in order to achieve the required terminal velocity when the central explosive was detonated. A descending charge with a terminal velocity of 32 m/s produced a cloud with discernably increased concentration compared with that dispersed from a stationary charge, the detonation of which hence generates a significantly enhanced blast wave beyond the scaled distance of 6 m/kg^{1/3}. The results also show the influence of the descending motion of the charge on the jetting phenomenon and the distorted shock front.

Superhydrophobic multi-scale ZnO nanostructures fabricated by chemical vapor deposition method.

Science.gov (United States)

Zhou, Ming; Feng, Chengheng; Wu, Chunxia; Ma, Weiwei; Cai, Lan

2009-07-01

The ZnO nanostructures were synthesized on Si(100) substrates by chemical vapor deposition (CVD) method. Different Morphologies of ZnO nanostructures, such as nanoparticle film, micro-pillar and micro-nano multi-structure, were obtained with different conditions. The results of XRD and TEM showed the good quality of ZnO crystal growth. Selected area electron diffraction analysis indicates the individual nano-wire is single crystal. The wettability of ZnO was studied by contact angle admeasuring apparatus. We found that the wettability can be changed from hydrophobic to super-hydrophobic when the structure changed from smooth particle film to single micro-pillar, nano-wire and micro-nano multi-scale structure. Compared with the particle film with contact angle (CA) of 90.7 degrees, the CA of single scale microstructure and sparse micro-nano multi-scale structure is 130-140 degrees, 140-150 degrees respectively. But when the surface is dense micro-nano multi-scale structure such as nano-lawn, the CA can reach to 168.2 degrees . The results indicate that microstructure of surface is very important to the surface wettability. The wettability on the micro-nano multi-structure is better than single-scale structure, and that of dense micro-nano multi-structure is better than sparse multi-structure.

Color change of Blue butterfly wing scales in an air - Vapor ambient

Science.gov (United States)

Kertész, Krisztián; Piszter, Gábor; Jakab, Emma; Bálint, Zsolt; Vértesy, Zofia; Biró, László Péter

2013-09-01

Photonic crystals are periodic dielectric nanocomposites, which have photonic band gaps that forbid the propagation of light within certain frequency ranges. The optical response of such nanoarchitectures on chemical changes in the environment is determined by the spectral change of the reflected light, and depends on the composition of the ambient atmosphere and on the nanostructure characteristics. We carried out reflectance measurements on closely related Blue lycaenid butterfly males possessing so-called "pepper-pot" type photonic nanoarchitecture in their scales covering their dorsal wing surfaces. Experiments were carried out changing the concentration and nature of test vapors while monitoring the spectral variations in time. All the tests were done with the sample temperature set at, and below the room temperature. The spectral changes were found to be linear with the increasing of concentration and the signal amplitude is higher at lower temperatures. The mechanism of reflectance spectra modification is based on capillary condensation of the vapors penetrating in the nanostructure. These structures of natural origin may serve as cheap, environmentally free and biodegradable sensor elements. The study of these nanoarchitectures of biologic origin could be the source of various new bioinspired systems.

Non-destructive identification of micrometer-scale minerals and their position within a bulk sample

DEFF Research Database (Denmark)

Sørensen, Henning O.; Hakim, Sepide S.; Pedersen, Stefan

2012-01-01

. Crushing or disintegrating a sample annihilates any possibility for gathering information from the texture of the porous media or the mineral assemblage close to the grains in question. A new method using three-dimensional X-ray diffraction (3DXRD) microscopy can be successfully applied to natural...... materials. We combined X-ray microtomography (XMT) and 3DXRD to investigate a sample of very fine-grained chalk containing fracture minerals. The XMT technique provides three-dimensional images of the particles and pore structure at very high resolution (350 nm voxel dimension) on samples less than 500 μm......Using the conventional techniques of mineralogy, it has been a challenge to determine mineral identity, crystal orientation and spatial position of micrometer-sized crystals that are embedded in a rock, sediment or soil. Traditionally, the individual grains must be extracted and analyzed separately...

A scanning tunneling microscope with a scanning range from hundreds of micrometers down to nanometer resolution.

Science.gov (United States)

Kalkan, Fatih; Zaum, Christopher; Morgenstern, Karina

2012-10-01

A beetle type stage and a flexure scanning stage are combined to form a two stages scanning tunneling microscope (STM). It operates at room temperature in ultrahigh vacuum and is capable of scanning areas up to 300 μm × 450 μm down to resolution on the nanometer scale. This multi-scale STM has been designed and constructed in order to investigate prestructured metallic or semiconducting micro- and nano-structures in real space from atomic-sized structures up to the large-scale environment. The principle of the instrument is demonstrated on two different systems. Gallium nitride based micropillars demonstrate scan areas up to hundreds of micrometers; a Au(111) surface demonstrates nanometer resolution.

Geophysical Modelling and Multi-Scale Studies in the Arctic Seiland Igneous Province: Millimeter to Micrometer Scale Mapping of the Magnetic Sources by High Resolution Magnetic Microscopy

Science.gov (United States)

Pastore, Z.; Church, N. S.; McEnroe, S. A.; Oda, H.; ter Maat, G. W.

2017-12-01

Rocks samples can have wide range of magnetic properties depending on composition, amount of ferromagnetic minerals, grain sizes and microstructures. These influence the magnetic anomalies from the micro to the global scale making the study of the magnetic properties of interest for multiple applications. Later geological processes such as serpentinization can significantly influence these properties and change the nature of the magnetic anomalies. Particularly, magnetic properties such as remanent magnetization and magnetic susceptibility are directly linked to the magnetic mineralogy composition and grain size and can provide useful information about the geological history of the source. Scanning magnetic microscopy is a highly sensitive and high-resolution magnetometric technique for mapping the magnetic field over a planar surface of a rock sample. The device measures the vertical component of the field above the thin sections and the technique offers a spatial resolution down to tens of micrometers and thus can be used to investigate discrete magnetic mineral grains or magnetic textures and structures, and the magnetic history of the sample. This technique allows a direct correlation between the mineral chemistry (through both electron and optical microscopy) and the magnetic properties. We present as case-study three thin section magnetic scans of two dunite samples from the Reinfjord Ultramafic complex, in northern Norway. The selected thin sections show different magnetic properties which reflect the magnetic petrology. One of the thin sections is from a pristine dunite sample; the other two are highly serpentinized with newly formed magnetite found in multiple, few micrometer thick, veins. We present the preliminary results obtained applying a forward modelling approach on the magnetic anomaly maps acquired over the thin sections. Modelling consists of uniformly-magnetized polygonal bodies whose geometry is constrained by the thickness of the thin section

Distribution of tropical tropospheric water vapor

Science.gov (United States)

Sun, De-Zheng; Lindzen, Richard S.

1993-01-01

Utilizing a conceptual model for tropical convection and observational data for water vapor, the maintenance of the vertical distribution of the tropical tropospheric water vapor is discussed. While deep convection induces large-scale subsidence that constrains the turbulent downgradient mixing to within the convective boundary layer and effectively dries the troposphere through downward advection, it also pumps hydrometeors into the upper troposphere, whose subsequent evaporation appears to be the major source of moisture for the large-scale subsiding motion. The development of upper-level clouds and precipitation from these clouds may also act to dry the outflow, thus explaining the low relative humidity near the tropopause. A one-dimensional model is developed to simulate the mean vertical structure of water vapor in the tropical troposphere. It is also shown that the horizontal variation of water vapor in the tropical troposphere above the trade-wind boundary layer can be explained by the variation of a moisture source that is proportional to the amount of upper-level clouds. Implications for the nature of water vapor feedback in global warming are discussed.

Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD.

Science.gov (United States)

Soria, José; Gauthier, Daniel; Flamant, Gilles; Rodriguez, Rosa; Mazza, Germán

2015-09-01

Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling the fine fragmentation following the triggering stage of a vapor explosion

International Nuclear Information System (INIS)

Darbord, I.

1997-01-01

In the frame of PWR severe accidents, where the core melt, this thesis studies one of the stages of an FCI (fuel coolant interaction) or vapor explosion. An FCI is a rapid evaporation of a coolant when it comes into contact with a hot liquid. More precisely, the subject of this study is the triggering stage of the FCI, when a fuel drop of diameter around one centimeter breaks up into many fragments, diameter of which is around a hundred micrometers. The model describes the cyclic collapse and growth of a vapor bubble around the fuel droplet and its fragmentation. The main features of the model are: - the destabilization of the film or the vapor bubble due to the growth of Rayleigh-Taylor instabilities (those form coolant jets that contact the fuel surface); - The mechanisms of fragmentation, following the contacts (in the case of entrapment of a certain amount of coolant in the fuel, the entrapped coolant evaporates violently after it has been heated to the homogeneous nucleation temperature); - the transient heat transfer from the fragments to the coolant and the elevated vapor production, which leads to an important expansion of the bubble (about this point, the cooling of the fragments has been described by a transient heat transfer coefficient linked to nucleate boiling). The results of the model show good agreement with experimental data. (Author)

Epitaxial Integration of Nanowires in Microsystems by Local Micrometer Scale Vapor Phase Epitaxy

DEFF Research Database (Denmark)

Mølhave, Kristian; Wacaser, Brent A.; Petersen, Dirch Hjorth

2008-01-01

deposition (CVD) or metal organic VPE (MOVPE). However, VPE of semiconducting nanowires is not compatible with several microfabrication processes due to the high synthesis temperatures and issues such as cross-contamination interfering with the intended microsystem or the VPE process. By selectively heating...... a small microfabricated heater, growth of nanowires can be achieved locally without heating the entire microsystem, thereby reducing the compatibility problems. The first demonstration of epitaxial growth of silicon nanowires by this method is presented and shows that the microsystem can be used for rapid...

Phase Composition Maps integrate mineral compositions with rock textures from the micro-meter to the thin section scale

Science.gov (United States)

Willis, Kyle V.; Srogi, LeeAnn; Lutz, Tim; Monson, Frederick C.; Pollock, Meagen

2017-12-01

Textures and compositions are critical information for interpreting rock formation. Existing methods to integrate both types of information favor high-resolution images of mineral compositions over small areas or low-resolution images of larger areas for phase identification. The method in this paper produces images of individual phases in which textural and compositional details are resolved over three orders of magnitude, from tens of micrometers to tens of millimeters. To construct these images, called Phase Composition Maps (PCMs), we make use of the resolution in backscattered electron (BSE) images and calibrate the gray scale values with mineral analyses by energy-dispersive X-ray spectrometry (EDS). The resulting images show the area of a standard thin section (roughly 40 mm × 20 mm) with spatial resolution as good as 3.5 μm/pixel, or more than 81 000 pixels/mm2, comparable to the resolution of X-ray element maps produced by wavelength-dispersive spectrometry (WDS). Procedures to create PCMs for mafic igneous rocks with multivariate linear regression models for minerals with solid solution (olivine, plagioclase feldspar, and pyroxenes) are presented and are applicable to other rock types. PCMs are processed using threshold functions based on the regression models to image specific composition ranges of minerals. PCMs are constructed using widely-available instrumentation: a scanning-electron microscope (SEM) with BSE and EDS X-ray detectors and standard image processing software such as ImageJ and Adobe Photoshop. Three brief applications illustrate the use of PCMs as petrologic tools: to reveal mineral composition patterns at multiple scales; to generate crystal size distributions for intracrystalline compositional zones and compare growth over time; and to image spatial distributions of minerals at different stages of magma crystallization by integrating textures and compositions with thermodynamic modeling.

A Meteorological Distribution System for High Resolution Terrestrial Modeling (MicroMet)

Science.gov (United States)

Liston, G. E.; Elder, K.

2004-12-01

Spatially distributed terrestrial models generally require atmospheric forcing data on horizontal grids that are of higher resolution than available meteorological data. Furthermore, the meteorological data collected may not necessarily represent the area of interest's meteorological variability. To address these deficiencies, computationally efficient and physically realistic methods must be developed to take available meteorological data sets (e.g., meteorological tower observations) and generate high-resolution atmospheric-forcing distributions. This poster describes MicroMet, a quasi-physically-based, but simple meteorological distribution model designed to produce high-resolution (e.g., 5-m to 1-km horizontal grid increments) meteorological data distributions required to run spatially distributed terrestrial models over a wide variety of landscapes. The model produces distributions of the seven fundamental atmospheric forcing variables required to run most terrestrial models: air temperature, relative humidity, wind speed, wind direction, incoming solar radiation, incoming longwave radiation, and precipitation. MicroMet includes a preprocessor that analyzes meteorological station data and identifies and repairs potential data deficiencies. The model uses known relationships between meteorological variables and the surrounding area (primarily topography) to distribute those variables over any given landscape. MicroMet performs two kinds of adjustments to available meteorological data: 1) when there are data at more than one location, at a given time, the data are spatially interpolated over the domain using a Barnes objective analysis scheme, and 2) physical sub-models are applied to each MicroMet variable to improve its realism at a given point in space and time with respect to the terrain. The three, 25-km by 25-km, Cold Land Processes Experiment (CLPX) mesoscale study areas (MSAs: Fraser, North Park, and Rabbit Ears) will be used as example MicroMet

Color change of Blue butterfly wing scales in an air – Vapor ambient

Energy Technology Data Exchange (ETDEWEB)

Kertész, Krisztián, E-mail: kertesz.krisztian@ttk.mta.hu [Institute of Technical Physics and Materials Science, Centre for Natural Sciences, H-1525 Budapest, PO Box 49, Hungary(http://www.nanotechnology.hu) (Hungary); Piszter, Gábor [Institute of Technical Physics and Materials Science, Centre for Natural Sciences, H-1525 Budapest, PO Box 49, Hungary(http://www.nanotechnology.hu) (Hungary); Jakab, Emma [Institute of Materials and Environmental Chemistry, Centre for Natural Sciences, H-1525 Budapest, PO Box 17 (Hungary); Bálint, Zsolt [Hungarian Natural History Museum, Baross utca 13, H-1088 Budapest (Hungary); Vértesy, Zofia; Biró, László Péter [Institute of Technical Physics and Materials Science, Centre for Natural Sciences, H-1525 Budapest, PO Box 49, Hungary(http://www.nanotechnology.hu) (Hungary)

2013-09-15

Photonic crystals are periodic dielectric nanocomposites, which have photonic band gaps that forbid the propagation of light within certain frequency ranges. The optical response of such nanoarchitectures on chemical changes in the environment is determined by the spectral change of the reflected light, and depends on the composition of the ambient atmosphere and on the nanostructure characteristics. We carried out reflectance measurements on closely related Blue lycaenid butterfly males possessing so-called “pepper-pot” type photonic nanoarchitecture in their scales covering their dorsal wing surfaces. Experiments were carried out changing the concentration and nature of test vapors while monitoring the spectral variations in time. All the tests were done with the sample temperature set at, and below the room temperature. The spectral changes were found to be linear with the increasing of concentration and the signal amplitude is higher at lower temperatures. The mechanism of reflectance spectra modification is based on capillary condensation of the vapors penetrating in the nanostructure. These structures of natural origin may serve as cheap, environmentally free and biodegradable sensor elements. The study of these nanoarchitectures of biologic origin could be the source of various new bioinspired systems.

Color change of Blue butterfly wing scales in an air – Vapor ambient

International Nuclear Information System (INIS)

Kertész, Krisztián; Piszter, Gábor; Jakab, Emma; Bálint, Zsolt; Vértesy, Zofia; Biró, László Péter

2013-01-01

Photonic crystals are periodic dielectric nanocomposites, which have photonic band gaps that forbid the propagation of light within certain frequency ranges. The optical response of such nanoarchitectures on chemical changes in the environment is determined by the spectral change of the reflected light, and depends on the composition of the ambient atmosphere and on the nanostructure characteristics. We carried out reflectance measurements on closely related Blue lycaenid butterfly males possessing so-called “pepper-pot” type photonic nanoarchitecture in their scales covering their dorsal wing surfaces. Experiments were carried out changing the concentration and nature of test vapors while monitoring the spectral variations in time. All the tests were done with the sample temperature set at, and below the room temperature. The spectral changes were found to be linear with the increasing of concentration and the signal amplitude is higher at lower temperatures. The mechanism of reflectance spectra modification is based on capillary condensation of the vapors penetrating in the nanostructure. These structures of natural origin may serve as cheap, environmentally free and biodegradable sensor elements. The study of these nanoarchitectures of biologic origin could be the source of various new bioinspired systems.

R-22 vapor explosions

International Nuclear Information System (INIS)

Anderson, R.P.; Armstrong, D.R.

1977-01-01

Previous experimental and theoretical studies of R-22 vapor explosions are reviewed. Results from two experimental investigations of vapor explosions in a medium scale R-22/water system are reported. Measurements following the drop of an unrestrained mass of R-22 into a water tank demonstrated the existence of two types of interaction behavior. Release of a constrained mass of R-22 beneath the surface of a water tank improved the visual resolution of the system thus allowing identification of two interaction mechansims: at low water temperatures, R-22/water contact would produce immediate violent boiling; at high water temperatures a vapor film formed around its R-22 as it was released, explosions were generated by a surface wave which initiated at a single location and propagated along the vapor film as a shock wave. A new vapor explosion model is proposed, it suggests explosions are the result of a sequence of three independent steps: an initial mixing phase, a trigger and growth phase, and a mature phase where a propagating shock wave accelerates the two liquids into a collapsing vapor layer causing a high velocity impact which finely fragments and intermixes the two liquids

Micrometer and nanometer scale photopatterning of proteins on glass surfaces by photo-degradation of films formed from oligo(ethylene glycol) terminated silanes.

Science.gov (United States)

Tizazu, Getachew; el Zubir, Osama; Patole, Samson; McLaren, Anna; Vasilev, Cvetelin; Mothersole, David J; Adawi, Ali; Hunter, C Neil; Lidzey, David G; Lopez, Gabriel P; Leggett, Graham J

2012-12-01

Exposure of films formed by the adsorption of oligo(ethylene glycol) (OEG) functionalized trichlorosilanes on glass to UV light from a frequency-doubled argon ion laser (244 nm) causes photodegradation of the OEG chain. Although the rate of degradation is substantially slower than for monolayers of OEG terminated thiolates on gold, it is nevertheless possible to form micrometer-scale patterns by elective adsorption of streptavidin to exposed regions. A low density of aldehyde functional groups is produced, and this enables derivatization with nitrilotriacetic acid via an amine linker. Complexation with nickel enables the site-specific immobilization of histidine-tagged yellow and green fluorescent proteins. Nanometer-scale patterns may be fabricated using a Lloyd's mirror interferometer, with a sample and mirror set at right angles to each other. At low exposures, partial degradation of the OEG chains does not remove the protein-resistance of the surface, even though friction force microscopy reveals the formation of patterns. At an exposure of ca. 18 J cm(-2), the modified regions became adhesive to proteins in a narrow region ca. 30 nm (λ/8) wide. As the exposure is increased further the lines quickly broaden to ca. 90 nm. Adjustment of the angle between the sample and mirror enables the fabrication of lines of His-tagged green fluorescent protein at a period of 340 nm that could be resolved using a confocal microscope.

Vapor Transport Through Fractures and Other High-Permeability Paths: Its Role in the Drift Scale Test at Yucca Mountain, Nevada

Science.gov (United States)

Mukhopadhyay, S.; Tsang, Y. W.

2001-12-01

Heating unsaturated fractured tuff sets off a series of complicated thermal-hydrological (TH) processes, which result in large-scale redistribution of moisture in the host rock. Moisture redistribution arises from boiling of water near heat sources, transport of vapor away from those heat sources, condensation of that vapor in cooler rock, and subsequent gravity drainage of condensate through fractures. Vapor transport through high-permeability paths, which include both the fractures in the rock and other conduits, contributes to the evolution of these TH processes in two ways. First, the highly permeable natural fractures provide easy passage for vapor away from the heat sources. Second, these fractures and other highly permeable conduits allow vapor (and the associated energy) to escape the rock through open boundaries of the test domain. The overall impact of vapor transport on the evolution of the TH processes can be more easily understood in the context of the Drift Scale Test (DST), the largest ever in situ heater test in unsaturated fractured tuff. The DST, in which a large volume of rock has been heated for four years now, is located in the middle nonlithophysal (Tptpmn) stratigraphic unit of Yucca Mountain, Nevada. The fractured tuff in Tptpmn contains many well-connected fractures. In the DST, heating is provided by nine cannister heaters placed in a five-meter-diameter Heated Drift (HD) and fifty wing heaters installed orthogonal to the axis of the HD. The test has many instrumentation boreholes, some of which are not sealed by packers or grout and may provide passage for vapor and energy. Of these conduits, the boreholes housing the wing heaters are most important for vapor transport because of their proximity to heat sources. While part of the vapor generated by heating moves away from the heat sources through the fractures and condenses elsewhere in the rock, the rest of the vapor, under gas-pressure difference, enters the HD by way of the high

Large-scale Fabrication of 2D Materials by Chemical Vapor Deposition

DEFF Research Database (Denmark)

Shivayogimath, Abhay

. This thesis aims to address some of the challenges associated with materials fabrication in order to lay the groundwork for commercial implementation of 2D materials. To improve graphene implementation in electronic applications, copper catalyst foils were engineered to reduce surface roughness, wrinkles...... this vast range of materials - without the lattice mismatch constraints of conventional 3D materials - into atomically engineered, artificial 3D crystals that pave the way for new physics, and subsequently, for new applications. 2D materials are expected to disrupt a number of industries in the future......, such as electronics, displays, energy, and catalysis. The key bottleneck for commercial implementation is in large-scale synthesis and subsequent fabrication of high quality devices. Chemical vapor deposition is considered to be the most economically feasible synthesis method to this end. In the case of graphene...

Effects of water vapor on protectiveness of Cr2O3 scale at 1073 K

Science.gov (United States)

Arifin, S. K.; Hamid, M.; Berahim, A. N.; Ani, M. H.

2018-01-01

Fe-Cr alloy is commonly being used as boiler tube’s material. It is subjected to prolonged exposure to water vapor oxidation. The ability to withstand high temperature corrosion can normally be attributed to the formation of a dense and slow growing Cr-rich-oxide scale known as chromia, Cr2O3 scale. However, oxidation may limit the alloy’s service lifetime due to decreasing of its protectiveness capability. This paper is to presents an experimental study of thermo gravimetric and Fourier transform infrared analysis of Cr2O3 at 1073 K in dry and humid environment. Samples were used from commercially available Cr2O3 powder. It was cold-pressed into pellet shape of 12 mm diameter and 3 mm thick with hydraulic press for 40 min at 48 MPa. It then sintered at 1173 K in inert gas environment for 8 h. The samples are cooled and placed in 5 mm diameter platinum pan. It is subjected to reaction in dry and wet environment at 1073 K by applying 100%-Ar and Ar-5%H2 gas. Each reaction period is 48 h utilizing Thermo Gravimetric Analyzer, TGA to quantify the mass changes. After the reaction, the samples then characterized with Fourier Transform Infrared Spectroscopy, FT-IR and Field Emission Electron Scanning Microscopy, FE-SEM. The TGA result shows mass decreasing ratio of Cr2O3 in wet (PH2O = 9.5x105Pa) and dry environment is at a factor of 1.2 while parabolic rate at 1.4. FT-IR results confirmed that water vapor significantly broaden the peaks, thus promotes the volatilization of Cr2O3 in wet sample. FESEM shows mostly packed and intact in dry while in wet sample, slightly porous particle arrangement compare to dry. It is concluded that water vapor species decreased Cr2O3 protectiveness capability.

Forsterite Shock Temperatures and Entropy: New Scaling Laws for Impact Melting and Vaporization

Science.gov (United States)

Davies, E.; Root, S.; Kraus, R. G.; Townsend, J. P.; Spaulding, D.; Stewart, S. T.; Jacobsen, S. B.; Fratanduono, D.; Millot, M. A.; Mattsson, T. R.; Hanshaw, H. L.

2017-12-01

The observed masses, radii and temperatures of thousands of extra-solar planets have challenged our theoretical understanding of planet formation and planetary structures. Planetary materials are subject to extreme pressures and temperatures during formation and within the present-day interiors of large bodies. Here, we focus on improving understanding of the physical properties of rocky planets for calculations of internal structure and the outcomes of giant impacts. We performed flyer plate impact experiments on forsterite [Mg2SiO4] on the Z-Machine at Sandia National Laboratory and decaying shock temperature measurements at the Omega EP laser at U. Rochester. At Z, planar, supported shock waves are generated in single crystal samples, permitting observation of both compressed and released states. Using available static and dynamic thermodynamic data, we calculate absolute entropy and heat capacity along the forsterite shock Hugoniot. Entropy and heat capacity on the Hugoniot are larger than previous estimates. Our data constrain the thermodynamic properties of forsterite liquid at high pressures and temperatures and the amount of melt and vapor produced during impact events. For an ambient pressure of 1 bar, shock-vaporization begins upon reaching the liquid region on the forsterite Hugoniot (about 200 GPa). Using hydrocode simulations of giant impacts between rocky planets with forsterite mantles and iron cores and the new experimentally-constrained forsterite shock entropy, we present a new scaling law for the fraction of mantle that is melted or vaporized by the initial shock wave. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525. Prepared by LLNL under Contract DE-AC52-07NA27344. Prepared by the Center

Pretreated Butterfly Wings for Tuning the Selective Vapor Sensing.

Science.gov (United States)

Piszter, Gábor; Kertész, Krisztián; Bálint, Zsolt; Biró, László Péter

2016-09-07

Photonic nanoarchitectures occurring in the scales of Blue butterflies are responsible for their vivid blue wing coloration. These nanoarchitectures are quasi-ordered nanocomposites which are constituted from a chitin matrix with embedded air holes. Therefore, they can act as chemically selective sensors due to their color changes when mixing volatile vapors in the surrounding atmosphere which condensate into the nanoarchitecture through capillary condensation. Using a home-built vapor-mixing setup, the spectral changes caused by the different air + vapor mixtures were efficiently characterized. It was found that the spectral shift is vapor-specific and proportional with the vapor concentration. We showed that the conformal modification of the scale surface by atomic layer deposition and by ethanol pretreatment can significantly alter the optical response and chemical selectivity, which points the way to the efficient production of sensor arrays based on the knowledge obtained through the investigation of modified butterfly wings.

On-tip sub-micrometer Hall probes for magnetic microscopy prepared by AFM lithography

International Nuclear Information System (INIS)

Gregusova, D.; Martaus, J.; Fedor, J.; Kudela, R.; Kostic, I.; Cambel, V.

2009-01-01

We developed a technology of sub-micrometer Hall probes for future application in scanning hall probe microscopy (SHPM) and magnetic force microscopy (MFM). First, the Hall probes of ∼9-μm dimensions are prepared on the top of high-aspect-ratio GaAs pyramids with an InGaP/AlGaAs/GaAs active layer using wet-chemical etching and non-planar lithography. Then we show that the active area of planar Hall probes can be downsized to sub-micrometer dimensions by local anodic oxidation technique using an atomic force microscope. Such planar probes are tested and their noise and magnetic field sensitivity are evaluated. Finally, the two technologies are combined to fabricate sub-micrometer Hall probes on the top of high-aspect ratio mesa for future SHPM and MFM techniques.

Non-equilibrium phenomena near vapor-liquid interfaces

CERN Document Server

Kryukov, Alexei; Puzina, Yulia

2013-01-01

This book presents information on the development of a non-equilibrium approach to the study of heat and mass transfer problems using vapor-liquid interfaces, and demonstrates its application to a broad range of problems. In the process, the following peculiarities become apparent: 1. At vapor condensation on the interface from gas-vapor mixture, non-condensable components can lock up the interface surface and condensation stops completely. 2. At the evolution of vapor film on the heater in superfluid helium (He-II), the boiling mass flux density from the vapor-liquid interface is effectively zero at the macroscopic scale. 3. In problems concerning the motion of He-II bridges inside capillaries filled by vapor, in the presence of axial heat flux the He-II bridge cannot move from the heater as would a traditional liquid, but in the opposite direction instead. Thus the heater attracts the superfluid helium bridge. 4. The shape of liquid-vapor interface at film boiling on the axis-symmetric heaters immersed in l...

Pretreated Butterfly Wings for Tuning the Selective Vapor Sensing

Directory of Open Access Journals (Sweden)

Gábor Piszter

2016-09-01

Full Text Available Photonic nanoarchitectures occurring in the scales of Blue butterflies are responsible for their vivid blue wing coloration. These nanoarchitectures are quasi-ordered nanocomposites which are constituted from a chitin matrix with embedded air holes. Therefore, they can act as chemically selective sensors due to their color changes when mixing volatile vapors in the surrounding atmosphere which condensate into the nanoarchitecture through capillary condensation. Using a home-built vapor-mixing setup, the spectral changes caused by the different air + vapor mixtures were efficiently characterized. It was found that the spectral shift is vapor-specific and proportional with the vapor concentration. We showed that the conformal modification of the scale surface by atomic layer deposition and by ethanol pretreatment can significantly alter the optical response and chemical selectivity, which points the way to the efficient production of sensor arrays based on the knowledge obtained through the investigation of modified butterfly wings.

Mobile vapor recovery and vapor scavenging unit

International Nuclear Information System (INIS)

Stokes, C.A.; Steppe, D.E.

1991-01-01

This patent describes a mobile anti- pollution apparatus, for the recovery of hydrocarbon emissions. It comprises a mobile platform upon which is mounted a vapor recovery unit for recovering vapors including light hydrocarbons, the vapor recovery unit having an inlet and an outlet end, the inlet end adapted for coupling to an external source of hydrocarbon vapor emissions to recover a portion of the vapors including light hydrocarbons emitted therefrom, and the outlet end adapted for connection to a means for conveying unrecovered vapors to a vapor scavenging unit, the vapor scavenging unit comprising an internal combustion engine adapted for utilizing light hydrocarbon in the unrecovered vapors exiting from the vapor recovery unit as supplemental fuel

Effect of impact angle on vaporization

Science.gov (United States)

Schultz, Peter H.

1996-09-01

Impacts into easily vaporized targets such as dry ice and carbonates generate a rapidly expanding vapor cloud. Laboratory experiments performed in a tenuous atmosphere allow deriving the internal energy of this cloud through well-established and tested theoretical descriptions. A second set of experiments under near-vacuum conditions provides a second measure of energy as the internal energy converts to kinetic energy of expansion. The resulting data allow deriving the vaporized mass as a function of impact angle and velocity. Although peak shock pressures decrease with decreasing impact angle (referenced to horizontal), the amount of impact-generated vapor is found to increase and is derived from the upper surface. Moreover, the temperature of the vapor cloud appears to decrease with decreasing angle. These unexpected results are proposed to reflect the increasing roles of shear heating and downrange hypervelocity ricochet impacts created during oblique impacts. The shallow provenance, low temperature, and trajectory of such vapor have implications for larger-scale events, including enhancement of atmospheric and biospheric stress by oblique terrestrial impacts and impact recycling of the early atmosphere of Mars.

Nanometer-resolution electron microscopy through micrometers-thick water layers

Energy Technology Data Exchange (ETDEWEB)

Jonge, Niels de, E-mail: niels.de.jonge@vanderbilt.edu [Vanderbilt University Medical Center, Department of Molecular Physiology and Biophysics, Nashville, TN 37232-0615 (United States); Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831-6064 (United States); Poirier-Demers, Nicolas; Demers, Hendrix [Universite de Sherbrooke, Electrical and Computer Engineering, Sherbrooke, Quebec J1K 2R1 (Canada); Peckys, Diana B. [Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831-6064 (United States); University of Tennessee, Center for Environmental Biotechnology, Knoxville, TN 37996-1605 (United States); Drouin, Dominique [Universite de Sherbrooke, Electrical and Computer Engineering, Sherbrooke, Quebec J1K 2R1 (Canada)

2010-08-15

Scanning transmission electron microscopy (STEM) was used to image gold nanoparticles on top of and below saline water layers of several micrometers thickness. The smallest gold nanoparticles studied had diameters of 1.4 nm and were visible for a liquid thickness of up to 3.3 {mu}m. The imaging of gold nanoparticles below several micrometers of liquid was limited by broadening of the electron probe caused by scattering of the electron beam in the liquid. The experimental data corresponded to analytical models of the resolution and of the electron probe broadening as function of the liquid thickness. The results were also compared with Monte Carlo simulations of the STEM imaging on modeled specimens of similar geometry and composition as used for the experiments. Applications of STEM imaging in liquid can be found in cell biology, e.g., to study tagged proteins in whole eukaryotic cells in liquid and in materials science to study the interaction of solid:liquid interfaces at the nanoscale.

DSMC simulations of vapor transport toward development of the lithium vapor box divertor concept

Science.gov (United States)

Jagoe, Christopher; Schwartz, Jacob; Goldston, Robert

2016-10-01

The lithium vapor divertor box concept attempts to achieve volumetric dissipation of the high heat efflux from a fusion power system. The vapor extracts the heat of the incoming plasma by ionization and radiation, while remaining localized in the vapor box due to differential pumping based on rapid condensation. Preliminary calculations with lithium vapor at densities appropriate for an NSTX-U-scale machine give Knudsen numbers between 0.01 and 1, outside both the range of continuum fluid dynamics and of collisionless Monte Carlo. The direct-simulation Monte Carlo (DSMC) method, however, can simulate rarefied gas flows in this regime. Using the solver contained in the OpenFOAM package, pressure-driven flows of water vapor will be analyzed. The use of water vapor in the relevant range of Knudsen number allows for a flexible similarity experiment to verify the reliability of the code before moving to tests with lithium. The simulation geometry consists of chains of boxes on a temperature gradient, connected by slots with widths that are a representative fraction of the dimensions of the box. We expect choked flow, sonic shocks, and order-of-magnitude pressure and density drops from box to box, but this expectation will be tested in the simulation and then experiment. This work is supported by the Princeton Environmental Institute.

Vapor-phase biofiltration: Laboratory and field experience

International Nuclear Information System (INIS)

Evans, P.J.; Bourbonais, K.A.; Peterson, L.E.; Lee, J.H.; Laakso, G.L.

1995-01-01

Application of vapor-phase bioreactors (VPBs) to petroleum hydrocarbons is complicated by the different mass transfer characteristics of aliphatics and aromatics. Laboratory- and pilot-scale VPB studies were conducted to evaluate treatment of soil vapor extraction (SVE) off-gas. A mixture of compost, perlite, and activated carbon was the selected medium based on pressure drop, microbial colonization, and adsorption properties. Two different pilot-scale reactors were built with a difference of 70:1 in scale. The smaller VPB's maximum effective elimination capacity (EC) was determined to be 7.2 g m -3 h -1 ; the larger unit's EC was 70% to 80% of this value. Low EC values may be attributable to a combination of mass-transfer and kinetic limitations

The liquid to vapor phase transition in excited nuclei

Energy Technology Data Exchange (ETDEWEB)

Elliott, J.B.; Moretto, L.G.; Phair, L.; Wozniak, G.J.; Beaulieu, L.; Breuer, H.; Korteling, R.G.; Kwiatkowski, K.; Lefort, T.; Pienkowski, L.; Ruangma, A.; Viola, V.E.; Yennello, S.J.

2001-05-08

For many years it has been speculated that excited nuclei would undergo a liquid to vapor phase transition. For even longer, it has been known that clusterization in a vapor carries direct information on the liquid-vapor equilibrium according to Fisher's droplet model. Now the thermal component of the 8 GeV/c pion + 197 Au multifragmentation data of the ISiS Collaboration is shown to follow the scaling predicted by Fisher's model, thus providing the strongest evidence yet of the liquid to vapor phase transition.

THE PHYSICS OF PROTOPLANETESIMAL DUST AGGLOMERATES. VI. EROSION OF LARGE AGGREGATES AS A SOURCE OF MICROMETER-SIZED PARTICLES

International Nuclear Information System (INIS)

Schraepler, Rainer; Blum, Juergen

2011-01-01

Observed protoplanetary disks consist of a large amount of micrometer-sized particles. Dullemond and Dominik pointed out for the first time the difficulty in explaining the strong mid-infrared excess of classical T Tauri stars without any dust-retention mechanisms. Because high relative velocities in between micrometer-sized and macroscopic particles exist in protoplanetary disks, we present experimental results on the erosion of macroscopic agglomerates consisting of micrometer-sized spherical particles via the impact of micrometer-sized particles. We find that after an initial phase, in which an impacting particle erodes up to 10 particles of an agglomerate, the impacting particles compress the agglomerate's surface, which partly passivates the agglomerates against erosion. Due to this effect, the erosion halts for impact velocities up to ∼30 m s -1 within our error bars. For higher velocities, the erosion is reduced by an order of magnitude. This outcome is explained and confirmed by a numerical model. In a next step, we build an analytical disk model and implement the experimentally found erosive effect. The model shows that erosion is a strong source of micrometer-sized particles in a protoplanetary disk. Finally, we use the stationary solution of this model to explain the amount of micrometer-sized particles in the observational infrared data of Furlan et al.

A Local Propagation for Vapor Explosions

International Nuclear Information System (INIS)

Ochiai, M.; Bankoff, S.G.

1976-01-01

Explosive boiling, defined as energy transfer leading to formation of vapor rapidly enough to produce large shock waves, has been widely studied in a number of contexts. Depending upon the nature and temperatures of the liquids and mode of contacting, large-scale mixing and explosive vaporization may occur, or alternatively, only relatively non-energetic, film-type boiling may exist. The key difference is whether a mechanism is operative for increasing the liquid-liquid interfacial area in a time scale consistent with the formation of a detonation wave. Small drops of a cold volatile liquid were dropped onto a free surface of a hot, non-volatile liquid. The critical Weber number for coalescence is obtained from the envelope of the film boiling region. Markedly different behavior for the two hot liquids is observed. A 'splash' theory for local propagation of vapor explosions in spontaneously nucleating liquid-liquid systems is now formulated. After a random contact is made, explosive growth and coalescence of the vapor bubbles occurs as soon as the surrounding pressure is relieved, resulting in a high-pressure vapor layer at the liquid-liquid contact area. This amounts to an impact pressure applied to the free surface, with a resulting velocity distribution obtained from potential flow theory. The peak pressure predictions are. consistent with data for Freon-oil mixing, but further evaluation will await additional experimental data. Nevertheless, the current inference is that a UO 2 -Na vapor explosion in a reactor environment cannot be visualized. In conclusion: The propagation model presented here differs in some details from that of Henry and Fauske, although both are consistent with some peak pressure data obtained by Henry, et al. Clearly, additional experimental information is needed for further evaluation of these theories. Nevertheless, it should be emphasized that even at this time a number of important observations concerning the requirements for a vapor

Auxiliary Electrodes for Chromium Vapor Sensors

Energy Technology Data Exchange (ETDEWEB)

Fergus, Jeffrey; Shahzad, Moaiz; Britt, Tommy

2018-05-15

Measurement of chromia-containing vapors in solid oxide fuel cell systems is useful for monitoring and addressing cell degradation caused by oxidation of the chomia scale formed on alloys for interconnects and balance-of-plant components. One approach to measuring chromium is to use a solid electrolyte with an auxiliary electrode that relates the partial pressure of the chromium containing species to the mobile species in the electrolyte. One example is YCrO3 which can equilibrate with the chromium containing vapor and yttrium in yttria stabilized zirconia to establish an oxygen activity. Another is Na2CrO4 which can equilibrate with the chromium-containing vapor to establish a sodium activity.

Luminescence property and large-scale production of ZnO nanowires by current heating deposition

International Nuclear Information System (INIS)

Singjai, P.; Jintakosol, T.; Singkarat, S.; Choopun, S.

2007-01-01

Large-scale production for ZnO nanowires has been demonstrated by current heating deposition. Based on the use of a solid-vapor phase carbothermal sublimation technique, a ZnO-graphite mixed rod was placed between two copper bars and gradually heated by passing current through it under constant flowing of argon gas at atmospheric pressure. The product seen as white films deposited on the rod surface was separated for further characterizations. The results have shown mainly comb-like structures of ZnO nanowires in diameter ranging from 50 to 200 nm and length up to several tens micrometers. From optical testing, ionoluminescence spectra of as-grown and annealed samples have shown high green emission intensities centered at 510 nm. In contrast, the small UV peak centered at 390 nm was observed clearly in the as-grown sample which almost disappeared after the annealing treatment

Interfacial Dynamics of Condensing Vapor Bubbles in an Ultrasonic Acoustic Field

Science.gov (United States)

Boziuk, Thomas; Smith, Marc; Glezer, Ari

2016-11-01

Enhancement of vapor condensation in quiescent subcooled liquid using ultrasonic actuation is investigated experimentally. The vapor bubbles are formed by direct injection from a pressurized steam reservoir through nozzles of varying characteristic diameters, and are advected within an acoustic field of programmable intensity. While kHz-range acoustic actuation typically couples to capillary instability of the vapor-liquid interface, ultrasonic (MHz-range) actuation leads to the formation of a liquid spout that penetrates into the vapor bubble and significantly increases its surface area and therefore condensation rate. Focusing of the ultrasonic beam along the spout leads to ejection of small-scale droplets from that are propelled towards the vapor liquid interface and result in localized acceleration of the condensation. High-speed video of Schlieren images is used to investigate the effects of the ultrasonic actuation on the thermal boundary layer on the liquid side of the vapor-liquid interface and its effect on the condensation rate, and the liquid motion during condensation is investigated using high-magnification PIV measurements. High-speed image processing is used to assess the effect of the actuation on the dynamics and temporal variation in characteristic scale (and condensation rate) of the vapor bubbles.

Physical vapor deposited thin films of lignins extracted from sugar cane bagasse: morphology, electrical properties, and sensing applications.

Science.gov (United States)

Volpati, Diogo; Machado, Aislan D; Olivati, Clarissa A; Alves, Neri; Curvelo, Antonio A S; Pasquini, Daniel; Constantino, Carlos J L

2011-09-12

The concern related to the environmental degradation and to the exhaustion of natural resources has induced the research on biodegradable materials obtained from renewable sources, which involves fundamental properties and general application. In this context, we have fabricated thin films of lignins, which were extracted from sugar cane bagasse via modified organosolv process using ethanol as organic solvent. The films were made using the vacuum thermal evaporation technique (PVD, physical vapor deposition) grown up to 120 nm. The main objective was to explore basic properties such as electrical and surface morphology and the sensing performance of these lignins as transducers. The PVD film growth was monitored via ultraviolet-visible (UV-vis) absorption spectroscopy and quartz crystal microbalance, revealing a linear relationship between absorbance and film thickness. The 120 nm lignin PVD film morphology presented small aggregates spread all over the film surface on the nanometer scale (atomic force microscopy, AFM) and homogeneous on the micrometer scale (optical microscopy). The PVD films were deposited onto Au interdigitated electrode (IDE) for both electrical characterization and sensing experiments. In the case of electrical characterization, current versus voltage (I vs V) dc measurements were carried out for the Au IDE coated with 120 nm lignin PVD film, leading to a conductivity of 3.6 × 10(-10) S/m. Using impedance spectroscopy, also for the Au IDE coated with the 120 nm lignin PVD film, dielectric constant of 8.0, tan δ of 3.9 × 10(-3), and conductivity of 1.75 × 10(-9) S/m were calculated at 1 kHz. As a proof-of-principle, the application of these lignins as transducers in sensing devices was monitored by both impedance spectroscopy (capacitance vs frequency) and I versus time dc measurements toward aniline vapor (saturated atmosphere). The electrical responses showed that the sensing units are sensible to aniline vapor with the process being

Sub-50 nm Scale to Micrometer Scale Soft Lithographic Patterning of Functional Materials

NARCIS (Netherlands)

George, A.

2011-01-01

This PhD thesis addresses two major issues: 1) Fabricating nanometer-scale patterns of functional materials, 2) Extending the applicability of soft lithographic processes to a wide range of functional materials on conventional silicon substrates and flexible plastic substrates. This thesis describes

Review on mechanism of directly fabricating wafer-scale graphene on dielectric substrates by chemical vapor deposition

Science.gov (United States)

Ning, Jing; Wang, Dong; Chai, Yang; Feng, Xin; Mu, Meishan; Guo, Lixin; Zhang, Jincheng; Hao, Yue

2017-07-01

To date, chemical vapor deposition on transition metal catalysts is a potential way to achieve low cost, high quality and uniform wafer-scale graphene. However, the removal and transfer process of the annoying catalytic metals underneath can bring large amounts of uncertain factors causing the performance deterioration of graphene, such as the pollution of surface polymeric residues, unmentioned doping and structural damages. Thus, to develop a technique of directly fabricating graphene on dielectric substrates is quite meaningful. In this review, we will present specific methods of catalyst- or transfer-free techniques for graphene growth and discuss the diversity of growth mechanisms.

Covering sources of toxic vapors with foam

International Nuclear Information System (INIS)

Aue, W. P.; Guidetti, F.

2009-01-01

In a case of chemical terrorism, first responders might well be confronted with a liquid source of toxic vapor which keeps spreading out its hazardous contents. With foam as an efficient and simple means, such a source could be covered up in seconds and the spread of vapors mitigated drastically. Once covered, the source could then wait for a longer time to be removed carefully and professionally by a decontamination team. In order to find foams useful for covering up toxic vapor sources, a large set of measurements has been performed in order to answer the following questions: - Which foams could be used for this purpose? - How thick should the foam cover be? - For how long would such a foam cover be effective? - Could the practical application of foam cause a spread of the toxic chemical? The toxic vapors sources included GB, GD and HD. Among the foams were 10 fire fighter foams (e.g. AFFF, protein) and the aqueous decontamination foam CASCAD. Small scale experiments showed that CASCAD is best suited for covering a toxic source; a 10 cm layer of it covers and decontaminates GB. The large scale experiments confirmed that any fire fighter foam is a suitable cover for a longer or shorter period.(author)

Absorption by airborne and deposited particles in the 8-13 micrometer range

Energy Technology Data Exchange (ETDEWEB)

Fischer, K; Grassl, H

1975-01-01

The absorption of radiation by natural aerosol particles was measured in the 8 to 13 micrometer wavelength interval. A comparison was made between an in situ method and measurements of particles of deposited form. The results are in agreement to about 30 percent. The main feature of aerosol absorption within the infrared window is a strong absorption peak near 9 micrometers caused by sulfate or quartz particles present in all continental aerosol types. Consequences for the atmospheric heat balance are clear sky cooling rates growing from about 2 per cent in the tropics to about 20 per cent of the total cooling in arctic regions under normal conditions, additionally increasing with increasing relative humidity.

The Synergistic Effect of Leukocyte Platelet-Rich Fibrin and Micrometer/Nanometer Surface Texturing on Bone Healing around Immediately Placed Implants: An Experimental Study in Dogs

Science.gov (United States)

Neiva, Rodrigo F.; Gil, Luiz Fernando; Tovar, Nick; Janal, Malvin N.; Marao, Heloisa Fonseca; Pinto, Nelson; Coelho, Paulo G.

2016-01-01

Aims. This study evaluated the effects of L-PRF presence and implant surface texture on bone healing around immediately placed implants. Methods. The first mandibular molars of 8 beagle dogs were bilaterally extracted, and implants (Blossom™, Intra-Lock International, Boca Raton, FL) were placed in the mesial or distal extraction sockets in an interpolated fashion per animal. Two implant surfaces were distributed per sockets: (1) dual acid-etched (DAE, micrometer scale textured) and (2) micrometer/nanometer scale textured (Ossean™ surface). L-PRF (Intraspin system, Intra-Lock International) was placed in a split-mouth design to fill the macrogap between implant and socket walls on one side of the mandible. The contralateral side received implants without L-PRF. A mixed-model ANOVA (at α = 0.05) evaluated the effect of implant surface, presence of L-PRF, and socket position (mesial or distal), individually or in combination on bone area fraction occupancy (BAFO). Results. BAFO values were significantly higher for the Ossean relative to the DAE surface on the larger mesial socket. The presence of L-PRF resulted in higher BAFO. The Ossean surface and L-PRF presence resulted in significantly higher BAFO. Conclusion. L-PRF and the micro-/nanometer scale textured surface resulted in increased bone formation around immediately placed implants. PMID:28042577

The Synergistic Effect of Leukocyte Platelet-Rich Fibrin and Micrometer/Nanometer Surface Texturing on Bone Healing around Immediately Placed Implants: An Experimental Study in Dogs

Directory of Open Access Journals (Sweden)

Rodrigo F. Neiva

2016-01-01

Full Text Available Aims. This study evaluated the effects of L-PRF presence and implant surface texture on bone healing around immediately placed implants. Methods. The first mandibular molars of 8 beagle dogs were bilaterally extracted, and implants (Blossom™, Intra-Lock International, Boca Raton, FL were placed in the mesial or distal extraction sockets in an interpolated fashion per animal. Two implant surfaces were distributed per sockets: (1 dual acid-etched (DAE, micrometer scale textured and (2 micrometer/nanometer scale textured (Ossean™ surface. L-PRF (Intraspin system, Intra-Lock International was placed in a split-mouth design to fill the macrogap between implant and socket walls on one side of the mandible. The contralateral side received implants without L-PRF. A mixed-model ANOVA (at α=0.05 evaluated the effect of implant surface, presence of L-PRF, and socket position (mesial or distal, individually or in combination on bone area fraction occupancy (BAFO. Results. BAFO values were significantly higher for the Ossean relative to the DAE surface on the larger mesial socket. The presence of L-PRF resulted in higher BAFO. The Ossean surface and L-PRF presence resulted in significantly higher BAFO. Conclusion. L-PRF and the micro-/nanometer scale textured surface resulted in increased bone formation around immediately placed implants.

Micrometer-sized isolated patterns of conductive ZnO derived by micromoulding

Energy Technology Data Exchange (ETDEWEB)

Goebel, Ole F.; Elshof, Johan E. ten; Blank, Dave A.H. [Inorganic Materials Science, Institute for Nanotechnology, University of Twente, Enschede (Netherlands)

2009-07-01

We succeeded in the fabrication of large-area patterns with micrometer-sized, isolated features of a simple oxide by a technically simple patterning method. By micromoulding a polymeric precursor solution for ZnO with an elastomeric (PDMS) mould, and a subsequent heat treatment, patterned ZnO films could be obtained. The features of the various patterns, including parallel or crossed lines and arrangements of dots, were several micrometers in diameter, and so were the spaces between them. The features were nearly isolated from each other, as the micromoulding process left behind a thin residual layer of ZnO of only about 15 nm thickness. By applying a tempering step, the transparent films could be rendered conductive. The process was applied successfully also to other oxide materials such as Bi2212 or CoFe2O4.

Infrared spectroscopic ellipsometry of micrometer-sized SiO2 line gratings

Science.gov (United States)

Walder, Cordula; Zellmeier, Matthias; Rappich, Jörg; Ketelsen, Helge; Hinrichs, Karsten

2017-09-01

For the design and process control of periodic nano-structured surfaces spectroscopic ellipsometry is already established in the UV-VIS spectral regime. The objective of this work is to show the feasibility of spectroscopic ellipsometry in the infrared, exemplarily, on micrometer-sized SiO2 line gratings grown on silicon wafers. The grating period ranges from 10 to about 34 μm. The IR-ellipsometric spectra of the gratings exhibit complex changes with structure variations. Especially in the spectral range of the oxide stretching modes, the presence of a Rayleigh singularity can lead to pronounced changes of the spectrum with the sample geometry. The IR-ellipsometric spectra of the gratings are well reproducible by calculations with the RCWA method (Rigorous Coupled Wave Analysis). Therefore, infrared spectroscopic ellipsometry allows the quantitative characterization and process control of micrometer-sized structures.

Vapor pressures and enthalpies of vaporization of azides

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Emel'yanenko, Vladimir N.; Algarra, Manuel; Manuel Lopez-Romero, J.; Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G.

2011-01-01

Highlights: → We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. → We examined consistency of new and available in the literature data. → Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization Δ l g H m of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

Application of ferrofluid density separation to particles in the micrometer-size range

International Nuclear Information System (INIS)

Strebin, R.S. Jr.; Johnson, J.W.; Robertson, D.M.

1976-02-01

A device designed and described by AVCO* as a ''Ferrofluid Density Separator''/sup (1)/ develops an apparent fluid density from nominally 2 to 20 g/cm 3 dependent on the magnitude of an imposed magnetic field gradient. The ferrofluid retains other normal properties of a liquid. One of these devices and a concentration series of ferrofluids were obtained in order to determine the practicality of separating groups of micrometer-size particles into density fractions. Such separations would be of enormous value in the study of various particle burdens because particles of interest are almost always diluted with overwhelming amounts of other particles. The results of a study of separations of micrometer-size particles with the ferrofluid density separator are presented

Low-cost, high-precision micro-lensed optical fiber providing deep-micrometer to deep-nanometer-level light focusing.

Science.gov (United States)

Wen, Sy-Bor; Sundaram, Vijay M; McBride, Daniel; Yang, Yu

2016-04-15

A new type of micro-lensed optical fiber through stacking appropriate high-refractive microspheres at designed locations with respect to the cleaved end of an optical fiber is numerically and experimentally demonstrated. This new type of micro-lensed optical fiber can be precisely constructed with low cost and high speed. Deep micrometer-scale and submicrometer-scale far-field light spots can be achieved when the optical fibers are multimode and single mode, respectively. By placing an appropriate teardrop dielectric nanoscale scatterer at the far-field spot of this new type of micro-lensed optical fiber, a deep-nanometer near-field spot can also be generated with high intensity and minimum joule heating, which is valuable in high-speed, high-resolution, and high-power nanoscale detection compared with traditional near-field optical fibers containing a significant portion of metallic material.

High-aspect-ratio and high-flatness Cu3(SiGe) nanoplatelets prepared by chemical vapor deposition.

Science.gov (United States)

Klementová, Mariana; Palatinus, Lukás; Novotný, Filip; Fajgar, Radek; Subrt, Jan; Drínek, Vladislav

2013-06-01

Cu3(SiGe) nanoplatelets were synthesized by low-pressure chemical vapor deposition of a SiH3C2H5/Ge2(CH3)6 mixture on a Cu-substrate at 500 degrees C, total pressure of 110-115 Pa, and Ge/Si molar ratio of 22. The nanoplatelets with composition Cu76Si15Ge12 are formed by the 4'-phase, and they are flattened perpendicular to the [001] direction. Their lateral dimensions reach several tens of micrometers in size, but they are only about 50 nm thick. Their surface is extremely flat, with measured root mean square roughness R(q) below 0.2 nm. The nanoplatelets grow via the non-catalytic vapor-solid mechanism and surface growth. In addition, nanowires and nanorods of various Cu-Si-Ge alloys were also obtained depending on the experimental conditions. Morphology of the resulting Cu-Si-Ge nanoobjects is very sensitive to the experimental parameters. The formation of nanoplatelets is associated with increased amount of Ge in the alloy.

The Oxidation Rate of SiC in High Pressure Water Vapor Environments

Science.gov (United States)

Opila, Elizabeth J.; Robinson, R. Craig

1999-01-01

CVD SiC and sintered alpha-SiC samples were exposed at 1316 C in a high pressure burner rig at total pressures of 5.7, 15, and 25 atm for times up to 100h. Variations in sample emittance for the first nine hours of exposure were used to determine the thickness of the silica scale as a function of time. After accounting for volatility of silica in water vapor, the parabolic rate constants for Sic in water vapor pressures of 0.7, 1.8 and 3.1 atm were determined. The dependence of the parabolic rate constant on the water vapor pressure yielded a power law exponent of one. Silica growth on Sic is therefore limited by transport of molecular water vapor through the silica scale.

Indirect heating of natural gas using vapor chambers; Aquecimento indireto de gas natural com uso de camaras de vapor

Energy Technology Data Exchange (ETDEWEB)

Milanez, Fernando H; Mantellil, Marcia H.B.; Borges, Thomaz P.F. [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica; Landa, Henrique G. de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

2005-07-01

Operation safety and reliability are major guidelines in the design of city-gate units. Conventional natural gas heaters operate by a indirect mechanism, where liquid water is used to transfer heat by natural convection between the combustion chamber and the natural gas coil. In this work, the concept of vapor chamber is evaluated as an indirect gas heater. In a vapor chamber, liquid water is in contact with the heat source, and vaporizes. The vapor condenses in contact with the heat sink. A reduced scale model was built and tested in order to compare these two heating concepts where the combustion chamber was replaced by electrical cartridge heaters. This engineering model can operate either as a conventional heater or as a vapor chamber. The comparison between the concepts was done by inducing a controlled power to the cartridges and by measuring the resulting temperature distributions. In the novel design, the heat exchanger efficiency increases, and the thermal inertia decreases, compared to the conventional system. The new sealed concept of the chamber prevents water evaporation losses. (author)

Pilot-scale studies of soil vapor extraction and bioventing for remediation of a gasoline spill at Cameron Station, Alexandria, Virginia

Energy Technology Data Exchange (ETDEWEB)

Harrison, W.; Joss, C.J.; Martino, L.E. [and others

1994-07-01

Approximately 10,000 gal of spilled gasoline and unknown amounts Of trichloroethylene and benzene were discovered at the US Army`s Cameron Station facility. Because the base is to be closed and turned over to the city of Alexandria in 1995, the Army sought the most rapid and cost-effective means of spill remediation. At the request of the Baltimore District of the US Army Corps of Engineers, Argonne conducted a pilot-scale study to determine the feasibility of vapor extraction and bioventing for resolving remediation problems and to critique a private firm`s vapor-extraction design. Argonne staff, working with academic and private-sector participants, designed and implemented a new systems approach to sampling, analysis and risk assessment. The US Geological Survey`s AIRFLOW model was adapted for the study to simulate the performance of possible remediation designs. A commercial vapor-extraction machine was used to remove nearly 500 gal of gasoline from Argonne-installed horizontal wells. By incorporating numerous design comments from the Argonne project team, field personnel improved the system`s performance. Argonne staff also determined that bioventing stimulated indigenous bacteria to bioremediate the gasoline spin. The Corps of Engineers will use Argonne`s pilot-study approach to evaluate remediation systems at field operation sites in several states.

Micrometer-sized Isolated Patterns of Conductive ZnO derived by Micromoulding

NARCIS (Netherlands)

Göbel, Ole F.; ten Elshof, Johan E.; Blank, David A.H.

2009-01-01

We succeeded in the fabrication of large-area patterns with micrometer-sized, isolated features of a simple oxide by a technically simple patterning method. By micromoulding a polymeric precursor solution for ZnO with an elastomeric (PDMS) mould, and a subsequent heat treatment, patterned ZnO films

Porous micrometer-sized MnO cubes as anode of lithium ion battery

International Nuclear Information System (INIS)

Fan, Xiaoyong; Li, Siheng; Lu, Li

2016-01-01

In this study, porous micrometer-sized MnO cubes have been designed and synthesized by hydrothermal treatment followed by high temperature annealing. The pore size is controlled by changing annealing temperature in order to achieve good electrochemical performance. The cube edge length is about 10 μm and the pore size changes from mesoporous to macroporous. The presence of pores in the MnO cubes is able to accommodate the volumetric changes during electrochemical cycling, and enables electrolyte easy penetration so that to improve the electrochemical performance. The porous micrometer-sized MnO cubes prepared by hydrothermal treatment at 100 °C followed by annealing at 700 °C delivers the best long-term and rate cyclability owing to its stable porous structure serving as lithium ion rapid transfer channels and enough pore volume to accommodate volumetric changes during electrochemical cycling. The reversible capacity in the first cycle is 615.9 mAh g"−"1at 0.2 A g"−"1, slightly decreases to 404.6 mAh g"−"1 at 1.0 A g"−"1in the 6"t"h cycle and remains at 425.5 mAh g"−"1 at 1.0 A g"−"1 even after 495 cycles. The same porous micrometer-sized MnO cube electrode delivers high rate reversible specific capacities of 201.8 and 50.4 mAh g"−"1 at 5.0 and 10.0 A g"−"1 respectively.

A Plant-Based Proxy for the Oxygen Isotope Ratio of Atmospheric Water Vapor

Science.gov (United States)

Helliker, B.

2007-12-01

Atmospheric water vapor is a major component of the global hydrological cycle, but the isotopic balance of vapor is largely unknown. It is shown here that the oxygen isotope ratio of leaf water in the epiphytic Crassulacean acid metabolism (CAM) plant Tillandsia usneoides (Spanish Moss) is controlled by the oxygen isotope ratio of atmospheric water vapor in both field and lab studies. Assuming that the leaf-water isotopic signature (and hence the atmospheric water vapor signature) is recorded in plant organic material, the atmospheric water vapor oxygen isotope ratios for Miami, Florida (USA) were reconstructed for several years from 1878 to 2005 using contemporary and herbarium specimens. T. usneoides ranges from Virginia, USA southwards through the tropics to Argentina, and the CAM epiphytic lifeform is widespread in other species. Therefore, epiphytes may be used to reconstruct the isotope ratio of atmospheric water for spatial scales that span over 60° of latitude and temporal scales that cover the last century of global temperature increase.

High Throughput Nanofabrication of Silicon Nanowire and Carbon Nanotube Tips on AFM Probes by Stencil-Deposited Catalysts

DEFF Research Database (Denmark)

Engstrøm, Daniel Southcott; Savu, Veronica; Zhu, Xueni

2011-01-01

scale nanostencil lithography. Individual vertical SiNWs were grown epitaxially by a catalytic vapor−liquid−solid (VLS) process and MWNTs were grown by a plasma-enhanced chemical vapor (PECVD) process on the AFM probes. The AFM probes were tested for imaging micrometers-deep trenches, where...... they demonstrated a significantly better performance than commercial high aspect ratio tips. Our method demonstrates a reliable and cost-efficient route toward wafer scale manufacturing of SiNW and MWNT AFM probes....

Macroscopic modeling for heat and water vapor transfer in dry snow by homogenization.

Science.gov (United States)

Calonne, Neige; Geindreau, Christian; Flin, Frédéric

2014-11-26

Dry snow metamorphism, involved in several topics related to cryospheric sciences, is mainly linked to heat and water vapor transfers through snow including sublimation and deposition at the ice-pore interface. In this paper, the macroscopic equivalent modeling of heat and water vapor transfers through a snow layer was derived from the physics at the pore scale using the homogenization of multiple scale expansions. The microscopic phenomena under consideration are heat conduction, vapor diffusion, sublimation, and deposition. The obtained macroscopic equivalent model is described by two coupled transient diffusion equations including a source term arising from phase change at the pore scale. By dimensional analysis, it was shown that the influence of such source terms on the overall transfers can generally not be neglected, except typically under small temperature gradients. The precision and the robustness of the proposed macroscopic modeling were illustrated through 2D numerical simulations. Finally, the effective vapor diffusion tensor arising in the macroscopic modeling was computed on 3D images of snow. The self-consistent formula offers a good estimate of the effective diffusion coefficient with respect to the snow density, within an average relative error of 10%. Our results confirm recent work that the effective vapor diffusion is not enhanced in snow.

A meteorological distribution system for high-resolution terrestrial modeling (MicroMet)

Science.gov (United States)

Glen E. Liston; Kelly Elder

2006-01-01

An intermediate-complexity, quasi-physically based, meteorological model (MicroMet) has been developed to produce high-resolution (e.g., 30-m to 1-km horizontal grid increment) atmospheric forcings required to run spatially distributed terrestrial models over a wide variety of landscapes. The following eight variables, required to run most terrestrial models, are...

Performance of a pilot-scale compost biofilter treating gasoline vapor

International Nuclear Information System (INIS)

Wright, W.F.; Schroeder, E.D.; Chang, D.P.Y.

1997-01-01

A pilot-scale compost biofiltration system was operated as gasoline soil vapor extraction site in Hayward, California for one year. The media was composed of equal volumes of compost and perlite, a bulking agent. Supplements added included nitrogen (as KNO 3 ), a gasoline degrading microbial inoculum, buffer (crushed oyster shell), and water. The biofiltration system was composed of four identical units with outside dimensions of 1.2 x 1.2 x 1.2 m (4 x 4 x 4 ft) operated in an up-flow mode. The units were configured in parallel during the first eight months and then reconfigured to two parallel systems of two units in series. Air flux values ranged from 0.29 to 1.0 m 3 /m 2 per min. Inlet total petroleum hydrogen hydrocarbon (TPH gas ) concentrations ranged from 310 to 2,700 mg/m 3 . The average empty bed contact time was 2.2 min. Following start-up, performance of the individual biofilters varied considerably for a seven-month period. The principal factor affecting performance appeared to be bed moisture content. Overall TPH gas removals reached 90% for short periods in one unit, and BTEX removals were typically above 90%. Drying resulted in channeling and loss of bed activity. Management of bed moisture content improved over the study period, and recovery of system performance was achieved without replacement of bed media. Overall TPH gas removals exceeded 90% during the final 50 days of the study

The reaction kinetics of lithium salt with water vapor

International Nuclear Information System (INIS)

Balooch, M.; Dinh, L.N.; Calef, D.F.

2002-01-01

The interaction of lithium salt (LiH and/or LiD) with water vapor in the partial pressure range of 10 -5 -2657 Pa has been investigated. The reaction probability of water with LiH cleaved in an ultra high vacuum environment was obtained using the modulated molecular beam technique. This probability was 0.11 and independent of LiH surface temperature, suggesting a negligible activation energy for the reaction in agreement with quantum chemical calculations. The value gradually reduced, however, to 0.007 as the surface concentration of oxygen containing product approached full coverage. As the film grew beyond a monolayer, the phase lag of hydrogen product increased from 0 deg. C to 20 deg. C and the reaction probability reduced further until it approached our detection limit (∼10 -4 ). This phase lag was attributed to a diffusion-limited process in this regime. For micrometer thick hydroxide films grown in high moisture concentration environment on LiD and LiH, the reaction probability reduced to ∼4x10 -7 and was independent of exposure time. In this regime of thick hydroxide films (LiOH and/or LiOD), microcracks generated in the films to release stress provided easier pathways for moisture to reach the interface. A modified microscope, capable of both atomic force microscopy and nanoindentation, was also employed to investigate the surface morphology of hydroxide monohydrate (LiOH · H 2 O and/or LiOD · H 2 O) grown on hydroxide at high water vapor partial pressures and the kinetics of this growth

Similarities and differences in vapor explosion criteria

International Nuclear Information System (INIS)

Cronenberg, A.W.

1978-01-01

An overview of recent ideas pertaining to vapor explosion criteria indicates that in general sense, a consensus of opinion is emerging on the conditions applicable to explosive vaporization. Experimental and theoretical work has lead a number of investigators to the formulation of such conditions which are quite similar in many respects, although the quantitative details of the model formulation of such conditions are somewhat different. All model concepts are consistent in that an initial period of stable film boiling, separating molten fuel from coolant, is considered necessary (at least for large-scale interactions and efficient intermixing), with subsequent breakdown of film boiling due to pressure and/or thermal effects, followed by intimate fuel-coolant contact and a rapid vaporization process which is sufficient to cause shock pressurization. Although differences arise as to the conditions for and the energetics associated with film boiling destabilization and the mode and energetics of fragmentation and intermixing. However, the principal area of difference seems to be the question of what constitutes the requisite condition(s) for rapid vapor production to cause shock pressurization

On the vapor-liquid equilibrium in hydroprocessing reactors

Energy Technology Data Exchange (ETDEWEB)

Chen, J.; Munteanu, M.; Farooqi, H. [National Centre for Upgrading Technology, Devon, AB (Canada)

2009-07-01

When petroleum distillates undergo hydrotreating and hydrocracking, the feedstock and hydrogen pass through trickle-bed catalytic reactors at high temperatures and pressures with large hydrogen flow. As such, the oil is partially vaporized and the hydrogen is partially dissolved in liquid to form a vapor-liquid equilibrium (VLE) system with both vapor and liquid phases containing oil and hydrogen. This may result in considerable changes in flow rates, physical properties and chemical compositions of both phases. Flow dynamics, mass transfer, heat transfer and reaction kinetics may also be modified. Experimental observations of VLE behaviours in distillates with different feedstocks under a range of operating conditions were presented. In addition, VLE was predicted along with its effects on distillates in pilot and commercial scale plants. tabs., figs.

Vapor pressure and enthalpy of vaporization of aliphatic propanediamines

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Chernyak, Yury

2012-01-01

Highlights: ► We measured vapor pressure of four aliphatic 1,3-diamines. ► Vaporization enthalpies at 298 K were derived. ► We examined consistency of new and available data in the literature. ► A group-contribution method for prediction was developed. - Abstract: Vapor pressures of four aliphatic propanediamines including N-methyl-1,3-propanediamine (MPDA), N,N-dimethyl-1,3-propanediamine (DMPDA), N,N-diethyl-1,3-propanediamine (DEPDA) and N,N,N′,N′-tetramethyl-1,3-propanediamine (4MPDA) were measured using the transpiration method. The vapor pressures developed in this work and reported in the literature were used to derive molar enthalpy of vaporization values at the reference temperature 298.15 K. An internal consistency check of the enthalpy of vaporization was performed for the aliphatic propanediamines studied in this work. A group-contribution method was developed for the validation and prediction vaporization enthalpies of amines and diamines.

FLUXNET: A new tool to study the temporal and spatial variability of ecosystem-scale carbon dioxide, water vapor, and energy flux densities

DEFF Research Database (Denmark)

Baldocchi, D.; Falge, E.; Gu, L.

2001-01-01

FLUXNET is a global network of micrometeorological flux measurement site's that measure the exchanges of carbon dioxide, water vapor, and energy between the biosphere and atmosphere. At present over 140 sites are operating on a long-term and continuous basis. Vegetation under study includes...... of annual ecosystem carbon and water balances, to quantify the response of stand-scale carbon dioxide and water vapor flux densities to controlling biotic and abiotic factors, and to validate a hierarchy of soil-plant-atmosphere trace gas exchange models. Findings so far include 1) net CO2 exchange......, it provides infrastructure for compiling, archiving, and distributing carbon, water, and energy flux measurement, and meteorological, plant, and soil data to the science community. (Data and site information are available online at the FLUXNET Web site, http://www-eosdis.oml.gov/FLUXNTET/.) Second...

Micrometer sized dust particles in a fr plasma under varying gravity conditions

NARCIS (Netherlands)

Beckers, J.; Stoffels, W.W.; Kroesen, G.M.W.; Ockenga, T.; Wolter, M.; Kersten, H.

2009-01-01

For diagnostic purposes micrometer-sized particles can be used as floating electrostatic probes. Once injected into a complex rf plasma, these particles will become negatively charged and can be trapped in the plasma sheath due to an equilibrium of several forces working on them, e.g. the

Vapor pressure and enthalpy of vaporization of linear aliphatic alkanediamines

International Nuclear Information System (INIS)

Pozdeev, Vasiliy A.; Verevkin, Sergey P.

2011-01-01

Highlights: → We measured vapor pressure of diamines H 2 N-(CH 2 ) n -NH 2 with n = 3 to 12. → Vaporization enthalpies at 298 K were derived. → We examined consistency of new and available in the literature data. → Enthalpies of vaporization show linear dependence on numbers n. → Enthalpies of vaporization correlate linearly with Kovat's indices. - Abstract: Vapor pressures and the molar enthalpies of vaporization of the linear aliphatic alkanediamines H 2 N-(CH 2 ) n -NH 2 with n = (3 to 12) have been determined using the transpiration method. A linear correlation of enthalpies of vaporization (at T = 298.15 K) of the alkanediamines with the number n and with the Kovat's indices has been found, proving the internal consistency of the measured data.

Study mechanism of growth and spallation of oxide scales formed after T91 steel oxidation in water vapor at 550 C

International Nuclear Information System (INIS)

Demizieux, Marie-Christine

2015-01-01

In the framework of the development of Generation IV reactors and specifically in the new Sodium Fast Reactor (SFR) project, Fe-9Cr ferritic-martensitic steels are candidates as structural materials for steam generators. Indeed, Fe-9Cr steels are already widely used in high temperature steam environments - like boilers and steam turbines- for their combination of creep strength and high thermal properties. Many studies have been focused on Fe-9Cr steels oxidation behavior between 550 C-700 C.Depending on the oxidizing environment, formation of a triplex (Fe-Cr spinel/magnetite/hematite) or duplex (Fe-Cr spinel/magnetite) oxide scales are reported.. Besides, for long time exposure in steam, the exfoliation of oxide scales can cause serious problems such as tube obstruction and steam turbine erosion. Consequently, this work has been dedicated to study, on the one hand the oxidation kinetics of T91 steel in water vapor environments, and on the other hand, the mechanisms leading to the spallation of the oxide scale. Oxidation tests have been carried out at 550 C in pure water vapor and in Ar/D_2O/H_2 environments with different hydrogen contents. Based on an analytical resolution, a quantitative modeling has shown that the 'available space model' proposed in the literature for duplex oxide scale formation well reproduces both scales growth kinetics and spinel oxide stoichiometry. Then, oxidized samples have been precisely characterized and it turns out that buckling then spalling of the oxide scale is always located in the magnetite layer. Voids observed in the magnetite layer are major initiation sites of de-cohesion of the outer oxide scale. A mechanism of formation of these voids has been proposed, in accordance with the mechanism of duplex scale formation. The derived model based on the assumption that vacancies accumulate where the iron vacancies flux divergence is maximal gives a good estimation of the location of pores inside the magnetite layer. Then, in order

Growth and characterization of stoichiometric BCN films on highly oriented pyrolytic graphite by radiofrequency plasma enhanced chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Mannan, Md. Abdul, E-mail: amannan75@yahoo.co [Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo, Saga 840-8502 (Japan); Synchrotron Radiation Research Unit, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Noguchi, Hideyuki; Kida, Tetsuya; Nagano, Masamitsu [Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo, Saga 840-8502 (Japan); Hirao, Norie; Baba, Yuji [Synchrotron Radiation Research Unit, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

2010-05-31

Hexagonal boron carbonitride (h-BCN) hybrid films have been synthesized on highly oriented pyrolytic graphite by radiofrequency plasma enhanced chemical vapor deposition using tris-(dimethylamino)borane as a single-source molecular precursor. The films were characterized by X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS) and Raman spectroscopic measurements. XPS measurement showed that the B atoms were bonded to C and N atoms to form the sp{sup 2}-B-C-N atomic hybrid chemical environment. The atomic composition estimated from the XPS of the typical sample was found to be almost B{sub 1}C{sub 1}N{sub 1}. NEXAFS spectra of the B K-edge and the N K-edge had the peaks due to the {pi}* and {sigma}* resonances of sp{sup 2} hybrid orbitals implying the existence of the sp{sup 2} hybrid configurations of h-BCN around the B atoms. The G band at 1592 and D band at 1352 cm{sup -1} in the Raman spectra also suggested the presence of the graphite-like sp{sup 2}-B-C-N atomic hybrid bonds. The films consisted of micrometer scale crystalline structure of around 10 {mu}m thick has been confirmed by the field emission scanning electron microscopy.

From nanometer aggregates to micrometer crystals

DEFF Research Database (Denmark)

Schultz, Logan Nicholas; Dideriksen, Knud; Lakshtanov, Leonid

2014-01-01

Grain size increases when crystals respond to dynamic equilibrium in a saturated solution. The pathway to coarsening is generally thought to be driven by Ostwald ripening, that is, simultaneous dissolution and reprecipitation, but models to describe Ostwald ripening neglect solid-solid interactions...... and crystal shapes. Grain coarsening of calcite, CaCO3, is relevant for biomineralization and commercial products and is an important process in diagenesis of sediments to rock during geological time. We investigated coarsening of pure, synthetic calcite powder of sub-micrometer diameter crystals and aged...... it in saturated solutions at 23, 100, and 200 °C for up to 261 days. Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) surface area analysis showed rapid coarsening at 100 and 200 °C. Evidence of particle growth at 23 °C was not visible by SEM, but high resolution X-ray diffraction (XRD) data...

Monolithic microwave integrated circuit water vapor radiometer

Science.gov (United States)

Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

1991-01-01

A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

Oxidative corrosion of spent UO2 fuel in vapor and dripping groundwater at 900C

International Nuclear Information System (INIS)

Finch, R. J.

1999-01-01

Corrosion of spent UO 2 fuel has been studied in experiments conducted for nearly six years. Oxidative dissolution in vapor and dripping groundwater at 90 C occurs via general corrosion at fuel-fragment surfaces. Dissolution along fuel-grain boundaries is also evident in samples contacted by the largest volumes of groundwater, and corroded grain boundaries extend at least 20 or 30 grains deep (> 200 microm), possibly throughout millimeter-sized fragments. Apparent dissolution of fuel along defects that intersect grain boundaries has created dissolution pits that are 50 to 200 nm in diameter. Dissolution pits penetrate 1-2 microm into each grain, producing a ''worm-like'' texture along fuel-grain-boundaries. Sub-micrometer-sized fuel shards are common between fuel grains and may contribute to the reactive surface area of fuel exposed to groundwater. Outer surfaces of reacted fuel fragments develop a fine-grained layer of corrosion products adjacent to the fuel (5-15 microm thick). A more coarsely crystalline layer of corrosion products commonly covers the fine-grained layer, the thickness of which varies considerably among samples (from less than 5 microm to greater than 40 microm). The thickest and most porous corrosion layers develop on fuel fragments exposed to the largest volumes of groundwater. Corrosion-layer compositions depend strongly on water flux, with uranyl oxy-hydroxides predominating in vapor experiments, and alkali and alkaline earth uranyl silicates predominating in high drip-rate experiments. Low drip-rate experiments exhibit a complex assemblage of corrosion products, including phases identified in vapor and high drip-rate experiments

Influence of Solar-Geomagnetic Disturbances on SABER Measurements of 4.3 Micrometer Emission and the Retrieval of Kinetic Temperature and Carbon Dioxide

Science.gov (United States)

Mertens, Christopher J.; Winick, Jeremy R.; Picard, Richard H.; Evans, David S.; Lopez-Puertas, Manuel; Wintersteiner, Peter P.; Xu, Xiaojing; Mlynczak, Martin G.; Russell, James M., III

2008-01-01

Thermospheric infrared radiance at 4.3 micrometers is susceptible to the influence of solar-geomagnetic disturbances. Ionization processes followed by ion-neutral chemical reactions lead to vibrationally excited NO(+) (i.e., NO(+)(v)) and subsequent 4.3 micrometer emission in the ionospheric E-region. Large enhancements of nighttime 4.3 m emission were observed by the TIMED/SABER instrument during the April 2002 and October-November 2003 solar storms. Global measurements of infrared 4.3 micrometer emission provide an excellent proxy to observe the nighttime E-region response to auroral dosing and to conduct a detailed study of E-region ion-neutral chemistry and energy transfer mechanisms. Furthermore, we find that photoionization processes followed by ion-neutral reactions during quiescent, daytime conditions increase the NO(+) concentration enough to introduce biases in the TIMED/SABER operational processing of kinetic temperature and CO2 data, with the largest effect at summer solstice. In this paper, we discuss solar storm enhancements of 4.3 micrometer emission observed from SABER and assess the impact of NO(+)(v) 4.3 micrometer emission on quiescent, daytime retrievals of Tk/CO2 from the SABER instrument.

Scaling behavior of columnar structure during physical vapor deposition

Science.gov (United States)

Meese, W. J.; Lu, T.-M.

2018-02-01

The statistical effects of different conditions in physical vapor deposition, such as sputter deposition, have on thin film morphology has long been the subject of interest. One notable effect is that of column development due to differential chamber pressure in the well-known empirical model called the Thornton's Structure Zone Model. The model is qualitative in nature and theoretical understanding with quantitative predictions of the morphology is still lacking due, in part, to the absence of a quantitative description of the incident flux distribution on the growth front. In this work, we propose an incident Gaussian flux model developed from a series of binary hard-sphere collisions and simulate its effects using Monte Carlo methods and a solid-on-solid growth scheme. We also propose an approximate cosine-power distribution for faster Monte Carlo sampling. With this model, it is observed that higher chamber pressures widen the average deposition angle, and similarly increase the growth of column diameters (or lateral correlation length) and the column-to-column separation (film surface wavelength). We treat both the column diameter and the surface wavelength as power laws. It is seen that both the column diameter exponent and the wavelength exponent are very sensitive to changes in pressure for low pressures (0.13 Pa to 0.80 Pa); meanwhile, both exponents saturate for higher pressures (0.80 Pa to 6.7 Pa) around a value of 0.6. These predictions will serve as guides to future experiments for quantitative description of the film morphology under a wide range of vapor pressure.

Laser pulse propagation in a meter scale rubidium vapor/plasma cell in AWAKE experiment

CERN Document Server

Joulaei, Atefeh; Berti, Nicolas; Kasparian, Jerome; Mirzanejhad, Saeed; Muggli, Patric

2016-01-01

We present the results of numerical studies of laser pulse propagating in a 3.5 cm Rb vapor cell in the linear dispersion regime by using a 1D model and a 2D code that has been modified for our special case. The 2D simulation finally aimed at finding laser beam parameters suitable to make the Rb vapor fully ionized to obtain a uniform, 10 m-long, at least 1 mm in radius plasma in the next step for the AWAKE experiment.

Experimental study of vapor explosion of molten salt and low boiling point liquid

International Nuclear Information System (INIS)

Iida, Yoshihiro; Takashima, Takeo

1987-01-01

Fundamental study of vapor explosion using small drops of high temperature liquid and low boiling point liquid and a series of small-scale vapor explosion tests are carried out. A single or plural drops of molten LiNO 3 are dropped into ethyl alcohol and the temperature range of two liquids wherein the fragmentation occurs is examined. The propagation phenomenon of vapor explosion between two drops is photographed and the pressure trace is proved to be well consistent with the behavior of the vapor bubble regions. A small amount of molten Flinak and tin which are enclosed in a test tube is dropped into tapped water. The temperature effect of two liquids onto the occurrence of vapor explosion is investigated. Some considerations are made with respect to the upper and lower temperature limits of vapor explosion to occur. A qualitative modeling of vapor explosion mechanism is proposed and discussed. (author)

VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

Energy Technology Data Exchange (ETDEWEB)

Eric M. Suuberg; Vahur Oja

1997-07-01

This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

High-Resolution IR Absorption Spectroscopy of Polycyclic Aromatic Hydrocarbons in the 3-micrometers Region: Role of Periphery

Science.gov (United States)

Maltseva, Elena; Petrignani, Annemieke; Candian, Alessandra; Mackie, Cameron J.; Huang, Xinchuan; Lee, Timothy J.; Tielens, Alexander G. G. M.; Oomens, Jos; Buma, Wybren Jan

2017-01-01

In this work we report on high-resolution IR absorption studies that provide a detailed view on how the peripheral structure of irregular polycyclic aromatic hydrocarbons (PAHs) affects the shape and position of their 3-micrometers absorption band. To this purpose we present mass-selected, high-resolution absorption spectra of cold and isolated phenanthrene, pyrene, benz[a]antracene, chrysene, triphenylene, and perylene molecules in the 2950-3150 per cm range. The experimental spectra are compared with standard harmonic calculations, and anharmonic calculations using a modified version of the SPECTRO program that incorporates a Fermi resonance treatment utilizing intensity redistribution. We show that the 3-micrometers region is dominated by the effects of anharmonicity, resulting in many more bands than would have been expected in a purely harmonic approximation. Importantly, we find that anharmonic spectra as calculated by SPECTRO are in good agreement with the experimental spectra. Together with previously reported high-resolution spectra of linear acenes, the present spectra provide us with an extensive dataset of spectra of PAHs with a varying number of aromatic rings, with geometries that range from open to highly-condensed structures, and featuring CH groups in all possible edge configurations. We discuss the astrophysical implications of the comparison of these spectra on the interpretation of the appearance of the aromatic infrared 3-micrometers band, and on features such as the two-component emission character of this band and the 3-micrometers emission plateau.

Mars atmospheric water vapor abundance: 1996-1997

Science.gov (United States)

Sprague, A. L.; Hunten, D. M.; Doose, L. R.; Hill, R. E.

2003-05-01

Measurements of martian atmospheric water vapor made throughout Ls = 18.0°-146.4° (October 3, 1996-July 12, 1997) show changes in Mars humidity on hourly, daily, and seasonal time scales. Because our observing program during the 1996-1997 Mars apparition did not include concomitant measurement of nearby CO 2 bands, high northern latitude data were corrected for dust and aerosol extinction assuming an optical depth of 0.8, consistent with ground-based and HST imaging of northern dust storms. All other measurements with airmass greater than 3.5 were corrected using a total optical depth of 0.5. Three dominant results from this data set are as follows: (1) pre- and post-opposition measurements made with the slit crossing many hours of local time on Mars' Earth-facing disk show a distinct diurnal pattern with highest abundances around and slightly after noon with low abundances in the late afternoon, (2) measurements of water vapor over the Mars Pathfinder landing site (Carl Sagan Memorial Station) on July 12, 1997, found 21 ppt μm in the spatial sector centered near 19° latitude, 36° longitude while abundances around the site varied from as low as 6 to as high as 28 ppt μm, and (3) water vapor abundance is patchy on hourly and daily time scales but follows the usual seasonal trends.

Structural and electronic properties of InN nanowire network grown by vapor-liquid-solid method

Science.gov (United States)

Barick, B. K.; Rodríguez-Fernández, Carlos; Cantarero, Andres; Dhar, S.

2015-05-01

Growth of InN nanowires have been carried out on quartz substrates at different temperatures by vapor-liquid-solid (VLS) technique using different thicknesses of Au catalyst layer. It has been found that a narrow window of Au layer thickness and growth temperature leads to multi-nucleation, in which each site acts as the origin of several nanowires. In this multi-nucleation regime, several tens of micrometer long wires with diameter as small as 20 nm are found to grow along [ 11 2 ¯ 0 ] direction (a-plane) to form a dense network. Structural and electronic properties of these wires are studied. As grown nanowires show degenerate n-type behavior. Furthermore, x-ray photoemission study reveals an accumulation of electrons on the surface of these nanowires. Interestingly, the wire network shows persistence of photoconductivity for several hours after switching off the photoexcitation.

Structural and electronic properties of InN nanowire network grown by vapor-liquid-solid method

Energy Technology Data Exchange (ETDEWEB)

Barick, B. K., E-mail: bkbarick@gmail.com, E-mail: subho-dh@yahoo.co.in; Dhar, S., E-mail: bkbarick@gmail.com, E-mail: subho-dh@yahoo.co.in [Department of Physics, Indian Institute of Technology, Bombay, Mumbai-400076 (India); Rodríguez-Fernández, Carlos; Cantarero, Andres [Materials Science Institute, University of Valencia, PO Box 22085, 46071 Valencia (Spain)

2015-05-15

Growth of InN nanowires have been carried out on quartz substrates at different temperatures by vapor-liquid-solid (VLS) technique using different thicknesses of Au catalyst layer. It has been found that a narrow window of Au layer thickness and growth temperature leads to multi-nucleation, in which each site acts as the origin of several nanowires. In this multi-nucleation regime, several tens of micrometer long wires with diameter as small as 20 nm are found to grow along [112{sup -}0] direction (a-plane) to form a dense network. Structural and electronic properties of these wires are studied. As grown nanowires show degenerate n-type behavior. Furthermore, x-ray photoemission study reveals an accumulation of electrons on the surface of these nanowires. Interestingly, the wire network shows persistence of photoconductivity for several hours after switching off the photoexcitation.

Recent advances towards a lithium vapor box divertor

Directory of Open Access Journals (Sweden)

R.J. Goldston

2017-08-01

Full Text Available Fusion power plants are likely to require near complete detachment of the divertor plasma from the divertor target plates, in order to have both acceptable heat flux at the target to avoid prompt damage and also acceptable plasma temperature at the target surface, to minimize long-term erosion. However hydrogenic and impurity puffing experiments show that detached operation leads easily to x-point MARFEs, impure plasmas, degradation in confinement, and lower helium pressure at the exhaust. The concept of the Lithium Vapor Box Divertor is to use local evaporation and strong differential pumping through condensation to localize low-Z gas-phase material that absorbs the plasma heat flux and so achieve detachment while avoiding these difficulties. The vapor localization has been confirmed using preliminary Navier–Stokes calculations. We use ADAS calculations of εcool, the plasma energy lost per injected lithium atom, to estimate the lithium vapor pressure, and so temperature, required for detachment, taking into account power balance. We also develop a simple model of detachment to evaluate the required upstream density, based on further taking into account dynamic pressure balance. A remarkable general result is found, not just for lithium-vapor-induced detachment, that the upstream density divided by the Greenwald-limit density scales as nup/nGW ∝ (P5/8/B3/8 Tdet1/2/(εcool+γTdet, with no explicit size scaling. Tdet is the temperature just before strong pressure loss, assumed to be ∼ ½ of the ionization potential of the dominant recycling species, and γ is the sheath heat transmission factor.

Copper-micrometer-sized diamond nanostructured composites

International Nuclear Information System (INIS)

Nunes, D; Livramento, V; Fernandes, H; Silva, C; Carvalho, P A; Shohoji, N; Correia, J B

2011-01-01

Reinforcement of a copper matrix with diamond enables tailoring the properties demanded for thermal management applications at high temperature, such as the ones required for heat sink materials in low activated nuclear fusion reactors. For an optimum compromise between thermal conductivity and mechanical properties, a novel approach based on multiscale diamond dispersions is proposed: a Cu-nanodiamond composite produced by milling is used as a nanostructured matrix for further dispersion of micrometer-sized diamond (μDiamond). A series of Cu-nanodiamond mixtures have been milled to establish a suitable nanodiamond fraction. A refined matrix with homogeneously dispersed nanoparticles was obtained with 4 at.% μDiamond for posterior mixture with microdiamond and subsequent consolidation. Preliminary consolidation by hot extrusion of a mixture of pure copper and μDiamond has been carried out to define optimal processing parameters. The materials produced were characterized by x-ray diffraction, scanning and transmission electron microscopy and microhardness measurements.

Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus

Science.gov (United States)

Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

2007-01-01

A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

Water vapor changes under global warming and the linkage to present-day interannual variabilities in CMIP5 models

Science.gov (United States)

Takahashi, Hanii; Su, Hui; Jiang, Jonathan H.

2016-12-01

The fractional water vapor changes under global warming across 14 Coupled Model Intercomparison Project Phase 5 simulations are analyzed. We show that the mean fractional water vapor changes under global warming in the tropical upper troposphere between 300 and 100 hPa range from 12.4 to 28.0 %/K across all models while the fractional water vapor changes are about 5-8 %/K in other regions and at lower altitudes. The "upper-tropospheric amplification" of the water vapor change is primarily driven by a larger temperature increase in the upper troposphere than in the lower troposphere per degree of surface warming. The relative contributions of atmospheric temperature and relative humidity changes to the water vapor change in each model vary between 71.5 to 131.8 % and 24.8 to -20.1 %, respectively. The inter-model differences in the water vapor change is primarily caused by differences in temperature change, except over the inter-tropical convergence zone within 10°S-10°N where the model differences due to the relative humidity change are significant. Furthermore, we find that there is generally a positive correlation between the rates of water vapor change for long-tem surface warming and those on the interannual time scales. However, the rates of water vapor change under long-term warming have a systematic offset from those on the inter-annual time scales and the dominant contributor to the differences also differs for the two time scales, suggesting caution needs to be taken when inferring long-term water vapor changes from the observed interannual variations.

High frequency nonlinear scattering from a micrometer to submicrometer sized lipid encapsulated contrast agent

NARCIS (Netherlands)

Goertz, David E.; Frijlink, Martijn E.; de Jong, N.; van der Steen, A.F.W.

2006-01-01

An experimental lipid encapsulated contrast agent comprised substantially of micrometer to submicrometer diameter bubbles was evaluated for its capacity to produce nonlinear scattering in response to high transmit frequencies. Agent characterization experiments were conducted at transmit frequencies

Vapor pressures and vaporization enthalpy of codlemone by correlation gas chromatography

International Nuclear Information System (INIS)

Schultz, Shannon M.; Harris, Harold H.; Chickos, James S.

2015-01-01

Highlights: • The vaporization enthalpy of codlemone has been evaluated. • The vapor pressure of codlemone has been evaluated from T = (298.15 to T b ) K. • Vapor pressures for the 1-alkanols standards are available from T = (298.15 to 500) K. - Abstract: The vapor pressure and vaporization enthalpy of codlemone (trans, trans 8,10-dodecadien-1-ol), the female sex hormone of the codling moth is evaluated by correlation gas chromatography using a series of saturated primary alcohols as standards. A vaporization enthalpy of (92.3 ± 2.6) kJ · mol −1 and a vapor pressure, p/Pa = (0.083 ± 0.012) were evaluated at T = 298.15 K. An equation for the evaluation of vapor pressure from ambient temperature to boiling has been derived by correlation for codlemone. The calculated boiling temperature of T B = 389 K at p = 267 Pa is within the temperature range reported in the literature. A normal boiling temperature of T B = (549.1 ± 0.1) K is also estimated by extrapolation

Si Nano wires Produced by Very High Frequency Plasma Enhanced Chemical Vapor Deposition (PECVD) via VLS Mechanism

International Nuclear Information System (INIS)

Yussof Wahab; Yussof Wahab; Habib Hamidinezhad; Habib Hamidinezhad

2013-01-01

Silicon nano wires (SiNWs) with diameter of about a few nanometers and length of 3 μm on silicon wafers were synthesized by very high frequency plasma enhanced chemical vapor deposition. Scanning electron microscopy (SEM) observations showed that the silicon nano wires were grown randomly and energy-dispersive X-ray spectroscopy analysis indicates that the nano wires have the composition of Si, Au and O elements. The SiNWs were characterized by high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. SEM micrographs displayed SiNWs that are needle-like with a diameter ranged from 30 nm at the top to 100 nm at the bottom of the wire and have length a few of micrometers. In addition, HRTEM showed that SiNWs consist of crystalline silicon core and amorphous silica layer. (author)

Petroleum Vapor Intrusion

Science.gov (United States)

One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. Intrusion of contaminant vapors into indoor spaces is of concern.

Laboratory testing of the in-well vapor-stripping system

International Nuclear Information System (INIS)

Gilmore, T.J.; Francois, O.

1996-03-01

The Volatile organic Compounds-Arid Integrated Demonstration (VOC-Arid ID) was implemented by the US Department of Energy's (DOE's) Office of Technology Development to develop and test new technologies for the remediation of organic chemicals in the subsurface. One of the technologies being tested under the VOC-Arid ID is the in-well vapor-stripping system. The in-well vapor-stripping concept was initially proposed by researchers at Stanford University and is currently under development through a collaboration between workers at Stanford University and DOE's Pacific Northwest National Laboratory. The project to demonstrate the in-well vapor-stripping technology is divided into three phases: (1) conceptual model and computer simulation, (2) laboratory testing, and (3) field demonstration. This report provides the methods and results of the laboratory testing in which a full-scale replica was constructed and tested above ground in a test facility located at DOE's Hanford Site, Washington. The system is a remediation technology designed to preferentially extract volatile organic compounds (VOCs) from contaminated groundwater by converting them to a vapor phase

Theoretical approaches and experimental evidence for liquid-vapor phase transitions in nuclei

Energy Technology Data Exchange (ETDEWEB)

Moretto, L.G.; Elliott, J.B.; Phair, L.; Wozniak, G.J.; Mader, C.M.; Chappars, A.

2001-01-01

The leptodermous approximation is applied to nuclear systems for T > 0. The introduction of surface corrections leads to anomalous caloric curves and to negative heat capacities in the liquid-gas coexistence region. Clusterization in the vapor is described by associating surface energy to clusters according to Fisher's formula. The three-dimensional Ising model, a leptodermous system par excellence, does obey rigorously Fisher's scaling up to the critical point. Multifragmentation data from several experiments including the ISiS and EOS Collaborations, as well as compound nucleus fragment emission at much lower energy follow the same scaling, thus providing the strongest evidence yet of liquid-vapor coexistence.

Vapor-fed bio-hybrid fuel cell.

Science.gov (United States)

Benyamin, Marcus S; Jahnke, Justin P; Mackie, David M

2017-01-01

Concentration and purification of ethanol and other biofuels from fermentations are energy-intensive processes, with amplified costs at smaller scales. To circumvent the need for these processes, and to potentially reduce transportation costs as well, we have previously investigated bio-hybrid fuel cells (FCs), in which a fermentation and FC are closely coupled. However, long-term operation requires strictly preventing the fermentation and FC from harming each other. We introduce here the concept of the vapor-fed bio-hybrid FC as a means of continuously extracting power from ongoing fermentations at ambient conditions. By bubbling a carrier gas (N 2 ) through a yeast fermentation and then through a direct ethanol FC, we protect the FC anode from the catalyst poisons in the fermentation (which are non-volatile), and also protect the yeast from harmful FC products (notably acetic acid) and from build-up of ethanol. Since vapor-fed direct ethanol FCs at ambient conditions have never been systematically characterized (in contrast to vapor-fed direct methanol FCs), we first assess the effects on output power and conversion efficiency of ethanol concentration, vapor flow rate, and FC voltage. The results fit a continuous stirred-tank reactor model. Over a wide range of ethanol partial pressures (2-8 mmHg), power densities are comparable to those for liquid-fed direct ethanol FCs at the same temperature, with power densities >2 mW/cm 2 obtained. We then demonstrate the continuous operation of a vapor-fed bio-hybrid FC with fermentation for 5 months, with no indication of performance degradation due to poisoning (of either the FC or the fermentation). It is further shown that the system is stable, recovering quickly from disturbances or from interruptions in maintenance. The vapor-fed bio-hybrid FC enables extraction of power from dilute bio-ethanol streams without costly concentration and purification steps. The concept should be scalable to both large and small

Structural and electronic properties of InN nanowire network grown by vapor-liquid-solid method

Directory of Open Access Journals (Sweden)

B. K. Barick

2015-05-01

Full Text Available Growth of InN nanowires have been carried out on quartz substrates at different temperatures by vapor-liquid-solid (VLS technique using different thicknesses of Au catalyst layer. It has been found that a narrow window of Au layer thickness and growth temperature leads to multi-nucleation, in which each site acts as the origin of several nanowires. In this multi-nucleation regime, several tens of micrometer long wires with diameter as small as 20 nm are found to grow along [ 11 2 ̄ 0 ] direction (a-plane to form a dense network. Structural and electronic properties of these wires are studied. As grown nanowires show degenerate n-type behavior. Furthermore, x-ray photoemission study reveals an accumulation of electrons on the surface of these nanowires. Interestingly, the wire network shows persistence of photoconductivity for several hours after switching off the photoexcitation.

Reduced-Pressure Chemical Vapor Deposition Growth of Isolated Ge Crystals and Suspended Layers on Micrometric Si Pillars.

Science.gov (United States)

Skibitzki, Oliver; Capellini, Giovanni; Yamamoto, Yuji; Zaumseil, Peter; Schubert, Markus Andreas; Schroeder, Thomas; Ballabio, Andrea; Bergamaschini, Roberto; Salvalaglio, Marco; Miglio, Leo; Montalenti, Francesco

2016-10-05

In this work, we demonstrate the growth of Ge crystals and suspended continuous layers on Si(001) substrates deeply patterned in high aspect-ratio pillars. The material deposition was carried out in a commercial reduced-pressure chemical vapor deposition reactor, thus extending the "vertical-heteroepitaxy" technique developed by using the peculiar low-energy plasma-enhanced chemical vapor deposition reactor, to widely available epitaxial tools. The growth process was thoroughly analyzed, from the formation of small initial seeds to the final coalescence into a continuous suspended layer, by means of scanning and transmission electron microscopy, X-ray diffraction, and μ-Raman spectroscopy. The preoxidation of the Si pillar sidewalls and the addition of hydrochloric gas in the reactants proved to be key to achieve highly selective Ge growth on the pillars top only, which, in turn, is needed to promote the formation of a continuous Ge layer. Thanks to continuum growth models, we were able to single out the different roles played by thermodynamics and kinetics in the deposition dynamics. We believe that our findings will open the way to the low-cost realization of tens of micrometers thick heteroepitaxial layer (e.g., Ge, SiC, and GaAs) on Si having high crystal quality.

High-throughput fabrication of micrometer-sized compound parabolic mirror arrays by using parallel laser direct-write processing

International Nuclear Information System (INIS)

Yan, Wensheng; Gu, Min; Cumming, Benjamin P

2015-01-01

Micrometer-sized parabolic mirror arrays have significant applications in both light emitting diodes and solar cells. However, low fabrication throughput has been identified as major obstacle for the mirror arrays towards large-scale applications due to the serial nature of the conventional method. Here, the mirror arrays are fabricated by using a parallel laser direct-write processing, which addresses this barrier. In addition, it is demonstrated that the parallel writing is able to fabricate complex arrays besides simple arrays and thus offers wider applications. Optical measurements show that each single mirror confines the full-width at half-maximum value to as small as 17.8 μm at the height of 150 μm whilst providing a transmittance of up to 68.3% at a wavelength of 633 nm in good agreement with the calculation values. (paper)

Supercurrent and multiple Andreev reflections in micrometer-long ballistic graphene Josephson junctions.

Science.gov (United States)

Zhu, Mengjian; Ben Shalom, Moshe; Mishchsenko, Artem; Fal'ko, Vladimir; Novoselov, Kostya; Geim, Andre

2018-02-08

Ballistic Josephson junctions are predicted to support a number of exotic physics processess, providing an ideal system to inject the supercurrent in the quantum Hall regime. Herein, we demonstrate electrical transport measurements on ballistic superconductor-graphene-superconductor junctions by contacting graphene to niobium with a junction length up to 1.5 μm. Hexagonal boron nitride encapsulation and one-dimensional edge contacts guarantee high-quality graphene Josephson junctions with a mean free path of several micrometers and record-low contact resistance. Transports in normal states including the observation of Fabry-Pérot oscillations and Sharvin resistance conclusively witness the ballistic propagation in the junctions. The critical current density J C is over one order of magnitude larger than that of the previously reported junctions. Away from the charge neutrality point, the I C R N product (I C is the critical current and R N the normal state resistance of junction) is nearly a constant, independent of carrier density n, which agrees well with the theory for ballistic Josephson junctions. Multiple Andreev reflections up to the third order are observed for the first time by measuring the differential resistance in the micrometer-long ballistic graphene Josephson junctions.

A low aspect ratio electrothermal gun for metal plasma vapor discharge and ceramic nanopowder production

International Nuclear Information System (INIS)

Kim, Kyoung Jin; Peterson, Dennis R.

2008-01-01

Traditionally, the electrothermal gun design has the bore of a large aspect ratio: however, a low aspect ratio design with a shorter bore length has been employed for efficient production of metal plasma vapors and synthesis of nanomaterials. In a comparison of the arc resistance-current relationship, a low aspect ratio design is found to exhibit distinctively different characteristics compared to a high aspect ratio design, and this trend is explained by the scaling law of plasma properties including theory of plasma electrical conductivity. A one-dimensional isothermal model has been applied to the present experiments to confirm the scaling laws, and it was found that the present modification of the electrothermal gun is able to produce fully ionized metal plasma vapor, while the plasma vapor produced in a conventional design is partially ionized. Also, by reacting metal plasma vapors with the controlled gases in the reaction chamber, nanoscale materials such as aluminum oxide, aluminum nitride, and titanium oxide were synthesized successfully

Injection molding of nanopatterned surfaces in the sub-micrometer range with induction heating aid

DEFF Research Database (Denmark)

Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano

2014-01-01

. A tool insert having a surface containing functional geometries in the sub-micrometer range was produced using aluminum anodization and nickel electroplating. In order to provide elevated mold temperatures necessary for the complete replica of the pattern, a new mold setup was developed, which allows...

PREVENTION AND CONTROL OF DIMETHYLAMINE VAPORS EMISSION: HERBICIDE PRODUCTION PLANT

Directory of Open Access Journals (Sweden)

Zorana Arsenijević

2008-11-01

Full Text Available The widely used herbicide, dimethylamine salt of 2,4-dichlorophenoxy acetic acid (2,4-D-DMA, is usually prepared by mixing a dimethylamine (DMA aqueous solution with a solid 2,4-dichlorophenoxy acetic acid (2,4-D. The vapors of the both, reactants and products, are potentially hazardous for the environment. The contribution of DMA vapors in overall pollution from this process is most significant, concerning vapor pressures data of these pollutants. Therefore, the control of the air pollution in the manufacture and handling of methylamines is very important. Within this paper, the optimal air pollution control system in preparation of 2,4-D-DMA was developed for the pesticides manufacturing industry. This study employed the simple pollution prevention concept to reduce the emission of DMA vapors at the source. The investigations were performed on the pilot plant scale. To reduce the emission of DMA vapors, the effluent gases from the herbicide preparation zone were passed through the packed bed scrubber (water - scrubbing medium, and the catalytic reactor in sequence. The end result is a substantially improved air quality in the working area, as well as in the urbanized areas located near the chemical plant.

GHz Rabi Flopping to Rydberg States in Hot Atomic Vapor Cells

International Nuclear Information System (INIS)

Huber, B.; Baluktsian, T.; Schlagmueller, M.; Koelle, A.; Kuebler, H.; Loew, R.; Pfau, T.

2011-01-01

We report on the observation of Rabi oscillations to a Rydberg state on a time scale below 1 ns in thermal rubidium vapor. We use a bandwidth-limited pulsed excitation and observe up to 6 full Rabi cycles within a pulse duration of ∼4 ns. We find good agreement between the experiment and numerical simulations based on a surprisingly simple model. This result shows that fully coherent dynamics with Rydberg states can be achieved even in thermal atomic vapor, thus suggesting small vapor cells as a platform for room-temperature quantum devices. Furthermore, the result implies that previous coherent dynamics in single-atom Rydberg gates can be accelerated by 3 orders of magnitude.

Cell visco-elasticity measured with AFM and optical trapping at sub-micrometer deformations.

Directory of Open Access Journals (Sweden)

Schanila Nawaz

Full Text Available The measurement of the elastic properties of cells is widely used as an indicator for cellular changes during differentiation, upon drug treatment, or resulting from the interaction with the supporting matrix. Elasticity is routinely quantified by indenting the cell with a probe of an AFM while applying nano-Newton forces. Because the resulting deformations are in the micrometer range, the measurements will be affected by the finite thickness of the cell, viscous effects and even cell damage induced by the experiment itself. Here, we have analyzed the response of single 3T3 fibroblasts that were indented with a micrometer-sized bead attached to an AFM cantilever at forces from 30-600 pN, resulting in indentations ranging from 0.2 to 1.2 micrometer. To investigate the cellular response at lower forces up to 10 pN, we developed an optical trap to indent the cell in vertical direction, normal to the plane of the coverslip. Deformations of up to two hundred nanometers achieved at forces of up to 30 pN showed a reversible, thus truly elastic response that was independent on the rate of deformation. We found that at such small deformations, the elastic modulus of 100 Pa is largely determined by the presence of the actin cortex. At higher indentations, viscous effects led to an increase of the apparent elastic modulus. This viscous contribution that followed a weak power law, increased at larger cell indentations. Both AFM and optical trapping indentation experiments give consistent results for the cell elasticity. Optical trapping has the benefit of a lower force noise, which allows a more accurate determination of the absolute indentation. The combination of both techniques allows the investigation of single cells at small and large indentations and enables the separation of their viscous and elastic components.

Point of net vapor generation and vapor void fraction in subcooled boiling

International Nuclear Information System (INIS)

Saha, P.; Zuber, N.

1974-01-01

An analysis is presented directed at predicting the point of net vapor generation and vapor void fraction in subcooled boiling. It is shown that the point of net vapor generation depends upon local conditions--thermal and fluid dynamic. Thus, at low mass flow rates the net vapor generation is determined by thermal conditions, whereas at high mass flow rates the phenomenon is hydrodynamically controlled. Simple criteria are derived which can be used to predict these local conditions for net vapor generation. These criteria are used to determine the vapor void fraction is subcooled boiling. Comparison between the results predicted by this analysis and experimental data presently available shows good agreement for wide range of operating conditions, fluids and geometries. (U.S.)

Modeling the fine fragmentation following the triggering stage of a vapor explosion; Modelisation de la fragmentaton fine lors de la phase de declenchement d`une explosion de vapeur

Energy Technology Data Exchange (ETDEWEB)

Darbord, I [CEA Grenoble, 38 (France). Service d` Etudes et de Modelisation Thermohydraulique

1997-06-11

In the frame of PWR severe accidents, where the core melt, this thesis studies one of the stages of an FCI (fuel coolant interaction) or vapor explosion. An FCI is a rapid evaporation of a coolant when it comes into contact with a hot liquid. More precisely, the subject of this study is the triggering stage of the FCI, when a fuel drop of diameter around one centimeter breaks up into many fragments, diameter of which is around a hundred micrometers. The model describes the cyclic collapse and growth of a vapor bubble around the fuel droplet and its fragmentation. The main features of the model are: - the destabilization of the film or the vapor bubble due to the growth of Rayleigh-Taylor instabilities (those form coolant jets that contact the fuel surface); - The mechanisms of fragmentation, following the contacts (in the case of entrapment of a certain amount of coolant in the fuel, the entrapped coolant evaporates violently after it has been heated to the homogeneous nucleation temperature); - the transient heat transfer from the fragments to the coolant and the elevated vapor production, which leads to an important expansion of the bubble (about this point, the cooling of the fragments has been described by a transient heat transfer coefficient linked to nucleate boiling). The results of the model show good agreement with experimental data. (Author) 68 refs.

Nonlinear response of tropical lower-stratospheric temperature and water vapor to ENSO

Directory of Open Access Journals (Sweden)

C. I. Garfinkel

2018-04-01

Full Text Available A series of simulations using the NASA Goddard Earth Observing System Chemistry–Climate Model are analyzed in order to aid in the interpretation of observed interannual and sub-decadal variability in the tropical lower stratosphere over the past 35 years. The impact of El Niño–Southern Oscillation on temperature and water vapor in this region is nonlinear in boreal spring. While moderate El Niño events lead to cooling in this region, strong El Niño events lead to warming, even as the response of the large-scale Brewer–Dobson circulation appears to scale nearly linearly with El Niño. This nonlinearity is shown to arise from the response in the Indo-West Pacific to El Niño: strong El Niño events lead to tropospheric warming extending into the tropical tropopause layer and up to the cold point in this region, where it allows for more water vapor to enter the stratosphere. The net effect is that both strong La Niña and strong El Niño events lead to enhanced entry water vapor and stratospheric moistening in boreal spring and early summer. These results lead to the following interpretation of the contribution of sea surface temperatures to the decline in water vapor in the early 2000s: the very strong El Niño event in 1997/1998, followed by more than 2 consecutive years of La Niña, led to enhanced lower-stratospheric water vapor. As this period ended in early 2001, entry water vapor concentrations declined. This effect accounts for approximately one-quarter of the observed drop.

Nonlinear response of tropical lower-stratospheric temperature and water vapor to ENSO

Science.gov (United States)

Garfinkel, Chaim I.; Gordon, Amit; Oman, Luke D.; Li, Feng; Davis, Sean; Pawson, Steven

2018-04-01

A series of simulations using the NASA Goddard Earth Observing System Chemistry-Climate Model are analyzed in order to aid in the interpretation of observed interannual and sub-decadal variability in the tropical lower stratosphere over the past 35 years. The impact of El Niño-Southern Oscillation on temperature and water vapor in this region is nonlinear in boreal spring. While moderate El Niño events lead to cooling in this region, strong El Niño events lead to warming, even as the response of the large-scale Brewer-Dobson circulation appears to scale nearly linearly with El Niño. This nonlinearity is shown to arise from the response in the Indo-West Pacific to El Niño: strong El Niño events lead to tropospheric warming extending into the tropical tropopause layer and up to the cold point in this region, where it allows for more water vapor to enter the stratosphere. The net effect is that both strong La Niña and strong El Niño events lead to enhanced entry water vapor and stratospheric moistening in boreal spring and early summer. These results lead to the following interpretation of the contribution of sea surface temperatures to the decline in water vapor in the early 2000s: the very strong El Niño event in 1997/1998, followed by more than 2 consecutive years of La Niña, led to enhanced lower-stratospheric water vapor. As this period ended in early 2001, entry water vapor concentrations declined. This effect accounts for approximately one-quarter of the observed drop.

Satellite- and ground-based observations of atmospheric water vapor absorption in the 940 nm region

International Nuclear Information System (INIS)

Albert, P.; Smith, K.M.; Bennartz, R.; Newnham, D.A.; Fischer, J.

2004-01-01

Ground-based measurements of direct absorption of solar radiation between 9000 and 13,000 cm -1 (770-1100 nm) with a spectral resolution of 0.05 cm -1 are compared with line-by-line simulations of atmospheric absorption based on different molecular databases (HITRAN 2000, HITRAN 99, HITRAN 96 and ESA-WVR). Differences between measurements and simulations can be reduced to a great amount by scaling the individual line intensities with spectral and database dependent scaling factors. Scaling factors are calculated for the selected databases using a Marquardt non-linear least-squares fit together with a forward model for 100 cm -1 wide intervals between 10,150 and 11,250 cm -1 as well as for the water vapor absorption channels of the Medium Resolution Imaging Spectrometer (MERIS) onboard the European Space Agency's (ESA) ENVISAT platform and the Modular Optoelectronic Scanner (MOS) on the Indian IRSP-3 platform, developed by the German Aerospace Centre (DLR). For the latter, the scaling coefficients are converted into correction factors for retrieved total columnar water vapor content and used for a comparison of MOS-based retrievals of total columnar atmospheric water vapor above cloud-free land surfaces with radio soundings. The scaling factors determined for 100 cm -1 wide intervals range from 0.85 for the ESA-WVR molecular database to 1.15 for HITRAN 96. The best agreement between measurements and simulations is achieved with HITRAN 99 and HITRAN 2000, respectively, using scaling factors between 0.9 and 1. The effects on the satellite-based retrievals of columnar atmospheric water vapor range from 2% (HITRAN 2000) to 12% (ESA-WVR)

The vapor pressure and enthalpy of vaporization of M-xylene

International Nuclear Information System (INIS)

Rothenberg, S.J.; Seiler, F.A.; Bechtold, W.E.; Eidson, A.F.

1988-01-01

We measured the vapor pressure of m-xylene over the temperature range 273 to 293 deg K with a single-sided capacitance manometer. The enthalpy of vaporization was 42.2 ± 0.1 (SE) kj/ g·mol. Combining our own data with previously published data, we recommend using the values 42.0, 40.6, and 39.1 (± 0.1) (SE) kjg·mol for the enthalpy of vaporization of m-xylene at 300, 340, and 380 deg. K, respectively, and a value for the change in heat capacity on vaporization (ΔCpdeg.) of 35 ± 3 (SE) J/g·mol·K over the temperature range studied. (author)

Vapor vacuum extraction treatability study at the Idaho National Engineering Laboratory

International Nuclear Information System (INIS)

Herd, M.D.; Matthern, G.; Michael, D.L.; Spang, N.; Downs, W.; Weidner, J.; Cleary, P.

1993-01-01

During the 1960s and early 1970s, barreled mixed waste containing volatile organic compounds (VOCS) and radioactive waste was buried at the Subsurface Disposal Area (SDA) at the Idaho National Engineering Laboratory (INEL) Radioactive Waste Management Complex (RWMC). Over time, some of the barrels have deteriorated allowing, VOC vapors to be released into the vadose zone. The primary VOC contaminates of concern are CCl 4 and trichloroethylene; however, chloroform, tetrachloroethylene, and 1,1,1-trichloroethane have also been detected. Vapor Vacuum Extraction (VVE) is one alternative being considered for remediation of the RWMC SDA vadose zone. A proposed pilot-scale treatability study (TS) will provide operation and maintenance costs for the design of the potential scale-up of the system

Surface characteristics, copper release, and toxicity of nano- and micrometer-sized copper and copper(II) oxide particles: a cross-disciplinary study.

OpenAIRE

Midander, Klara; Cronholm, Pontus; Karlsson, Hanna L.; Elihn, Karine; Moller, Lennart; Leygraf, Christofer; Wallinder, Inger Odnevall

2009-01-01

An interdisciplinary and multianalytical research effort is undertaken to assess the toxic aspects of thoroughly characterized nano- and micrometer-sized particles of oxidized metallic copper and copper(II) oxide in contact with cultivated lung cells, as well as copper release in relevant media. All particles, except micrometer-sized Cu, release more copper in serum-containing cell medium (supplemented Dulbecco's minimal essential medium) compared to identical exposures in phosphate-buffered ...

High Temperature Corrosion of Silicon Carbide and Silicon Nitride in Water Vapor

Science.gov (United States)

Opila, E. J.; Robinson, Raymond C.; Cuy, Michael D.; Gray, Hugh R. (Technical Monitor)

2002-01-01

Silicon carbide (SiC) and silicon nitride (Si3N4) are proposed for applications in high temperature combustion environments containing water vapor. Both SiC and Si3N4 react with water vapor to form a silica (SiO2) scale. It is therefore important to understand the durability of SiC, Si3N4 and SiO2 in water vapor. Thermogravimetric analyses, furnace exposures and burner rig results were obtained for these materials in water vapor at temperatures between 1100 and 1450 C and water vapor partial pressures ranging from 0.1 to 3.1 atm. First, the oxidation of SiC and Si3N4 in water vapor is considered. The parabolic kinetic rate law, rate dependence on water vapor partial pressure, and oxidation mechanism are discussed. Second, the volatilization of silica to form Si(OH)4(g) is examined. Mass spectrometric results, the linear kinetic rate law and a volatilization model based on diffusion through a gas boundary layer are discussed. Finally, the combined oxidation and volatilization reactions, which occur when SiC or Si3N4 are exposed in a water vapor-containing environment, are presented. Both experimental evidence and a model for the paralinear kinetic rate law are shown for these simultaneous oxidation and volatilization reactions.

Modeled and Empirical Approaches for Retrieving Columnar Water Vapor from Solar Transmittance Measurements in the 0.72, 0.82, and 0.94 Micrometer Absorption Bands

Science.gov (United States)

Ingold, T.; Schmid, B.; Maetzler, C.; Demoulin, P.; Kaempfer, N.

2000-01-01

A Sun photometer (18 channels between 300 and 1024 nm) has been used for measuring the columnar content of atmospheric water vapor (CWV) by solar transmittance measurements in absorption bands with channels centered at 719, 817, and 946 nm. The observable is the band-weighted transmittance function defined by the spectral absorption of water vapor and the spectral features of solar irradiance and system response. The transmittance function is approximated by a three-parameter model. Its parameters are determined from MODTRAN and LBLRTM simulations or empirical approaches using CWV data of a dual-channel microwave radiometer (MWR) or a Fourier transform spectrometer (FTS). Data acquired over a 2-year period during 1996-1998 at two different sites in Switzerland, Bern (560 m above sea level (asl)) and Jungfraujoch (3580 m asl) were compared to MWR, radiosonde (RS), and FTS retrievals. At the low-altitude station with an average CWV amount of 15 mm the LBLRTM approach (based on recently corrected line intensities) leads to negligible biases at 719 and 946 nm if compared to an average of MWR, RS, and GPS retrievals. However, at 817 nm an overestimate of 2.7 to 4.3 mm (18-29%) remains. At the high-altitude station with an average CWV amount of 1.4 mm the LBLRTM approaches overestimate the CWV by 1.0, 1.4. and 0.1 mm (58, 76, and 3%) at 719, 817, and 946 nm, compared to the ITS instrument. At the low-altitude station, CWV estimates, based on empirical approaches, agree with the MWR within 0.4 mm (2.5% of the mean); at the high-altitude site with a factor of 10 less water vapor the agreement of the sun photometers (SPM) with the ITS is 0.0 to 0.2 mm (1 to 9% of the mean CWV there). Sensitivity analyses show that for the conditions met at the two stations with CWV ranging from 0.2 to 30 mm, the retrieval errors are smallest if the 946 nm channel is used.

The vapor pressure and enthalpy of vaporization of M-xylene

Energy Technology Data Exchange (ETDEWEB)

Rothenberg, S J; Seiler, F A; Bechtold, W E; Eidson, A F

1988-12-01

We measured the vapor pressure of m-xylene over the temperature range 273 to 293 deg K with a single-sided capacitance manometer. The enthalpy of vaporization was 42.2 {+-} 0.1 (SE) kj/ g{center_dot}mol. Combining our own data with previously published data, we recommend using the values 42.0, 40.6, and 39.1 ({+-} 0.1) (SE) kjg{center_dot}mol for the enthalpy of vaporization of m-xylene at 300, 340, and 380 deg. K, respectively, and a value for the change in heat capacity on vaporization ({delta}Cpdeg.) of 35 {+-} 3 (SE) J/g{center_dot}mol{center_dot}K over the temperature range studied. (author)

Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

Energy Technology Data Exchange (ETDEWEB)

Lee, S.H.D.; Teats, F.G.; Swift, W.M. (Argonne National Lab., IL (United States)); Banerjee, D.D. (Illinois Clean Coal Inst., Carterville, IL (United States))

1993-01-01

Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950[degree]C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

Energy Technology Data Exchange (ETDEWEB)

Lee, S.H.D.; Teats, F.G.; Swift, W.M. [Argonne National Lab., IL (United States); Banerjee, D.D. [Illinois Clean Coal Inst., Carterville, IL (United States)

1993-04-01

Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950{degree}C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

Pore-scale modeling of vapor transport in partially saturated capillary tube with variable area using chemical potential

DEFF Research Database (Denmark)

Addassi, Mouadh; Schreyer, Lynn; Johannesson, Björn

2016-01-01

Here we illustrate the usefulness of using the chemical potential as the primary unknown by modeling isothermal vapor transport through a partially saturated cylindrically symmetric capillary tube of variable cross-sectional area using a single equation. There are no fitting parameters and the nu......Here we illustrate the usefulness of using the chemical potential as the primary unknown by modeling isothermal vapor transport through a partially saturated cylindrically symmetric capillary tube of variable cross-sectional area using a single equation. There are no fitting parameters...... and the numerical solutions to the equation are compared with experimental results with excellent agreement. We demonstrate that isothermal vapor transport can be accurately modeled without modeling the details of the contact angle, microscale temperature fluctuations, or pressure fluctuations using a modification...

Heavy metal vaporization and abatement during thermal treatment of modified wastes

International Nuclear Information System (INIS)

Rio, S.; Verwilghen, C.; Ramaroson, J.; Nzihou, A.; Sharrock, P.

2007-01-01

This study examines the vaporization percentage and partitioning of heavy metals Cd, Pb and Zn during thermal treatment of wastes with added PVC, heavy metals or phosphate, and the efficiency of sorbents for removal of these metallic compounds in flue gas of an industrial solid waste incinerator. Firstly, vaporization experiments were carried out to determine the behavior of heavy metals during combustion under various conditions (type of waste, temperature, presence of chloride or phosphate ...). The experimental results show relatively high vaporization percentage of metallic compounds within fly ash and limestone matrix while heavy metals within sediments treated with phosphoric acid are less volatile. Vaporization of metals increases with increasing temperature and with chloride addition. The thermal behavior of the selected heavy metals and their removal by sorbents (sodium bicarbonate, activated carbon) was also studied in an industrial solid waste incinerator. These pilot scale experiments confirm that heavy metals are concentrated in fly ashes and cyclone residues, thus effectively controlling their release to the atmosphere

Atmospheric solar heating rate in the water vapor bands

Science.gov (United States)

Chou, Ming-Dah

1986-01-01

The total absorption of solar radiation by water vapor in clear atmospheres is parameterized as a simple function of the scaled water vapor amount. For applications to cloudy and hazy atmospheres, the flux-weighted k-distribution functions are computed for individual absorption bands and for the total near-infrared region. The parameterization is based upon monochromatic calculations and follows essentially the scaling approximation of Chou and Arking, but the effect of temperature variation with height is taken into account in order to enhance the accuracy. Furthermore, the spectral range is extended to cover the two weak bands centered at 0.72 and 0.82 micron. Comparisons with monochromatic calculations show that the atmospheric heating rate and the surface radiation can be accurately computed from the parameterization. Comparisons are also made with other parameterizations. It is found that the absorption of solar radiation can be computed reasonably well using the Goody band model and the Curtis-Godson approximation.

Removal of gasoline vapors from air streams by biofiltration

Energy Technology Data Exchange (ETDEWEB)

Apel, W.A.; Kant, W.D.; Colwell, F.S.; Singleton, B.; Lee, B.D.; Andrews, G.F.; Espinosa, A.M.; Johnson, E.G.

1993-03-01

Research was performed to develop a biofilter for the biodegradation of gasoline vapors. The overall goal of this effort was to provide information necessary for the design, construction, and operation of a commercial gasoline vapor biofilter. Experimental results indicated that relatively high amounts of gasoline vapor adsorption occur during initial exposure of the biofilter bed medium to gasoline vapors. Biological removal occurs over a 22 to 40{degrees}C temperature range with removal being completely inhibited at 54{degrees}C. The addition of fertilizer to the relatively fresh bed medium used did not increase the rates of gasoline removal in short term experiments. Microbiological analyses indicated that high levels of gasoline degrading microbes are naturally present in the bed medium and that additional inoculation with hydrocarbon degrading cultures does not appreciably increase gasoline removal rates. At lower gasoline concentrations, the vapor removal rates were considerably lower than those at higher gasoline concentrations. This implies that system designs facilitating gasoline transport to the micro-organisms could substantially increase gasoline removal rates at lower gasoline vapor concentrations. Test results from a field scale prototype biofiltration system showed volumetric productivity (i.e., average rate of gasoline degradation per unit bed volume) values that were consistent with those obtained with laboratory column biofilters at similar inlet gasoline concentrations. In addition, total benzene, toluene, ethyl-benzene, and xylene (BTEX) removal over the operating conditions employed was 50 to 55%. Removal of benzene was approximately 10 to 15% and removal of the other members of the BTEX group was much higher, typically >80%.

Removal of gasoline vapors from air streams by biofiltration

Energy Technology Data Exchange (ETDEWEB)

Apel, W.A.; Kant, W.D.; Colwell, F.S.; Singleton, B.; Lee, B.D.; Andrews, G.F.; Espinosa, A.M.; Johnson, E.G.

1993-03-01

Research was performed to develop a biofilter for the biodegradation of gasoline vapors. The overall goal of this effort was to provide information necessary for the design, construction, and operation of a commercial gasoline vapor biofilter. Experimental results indicated that relatively high amounts of gasoline vapor adsorption occur during initial exposure of the biofilter bed medium to gasoline vapors. Biological removal occurs over a 22 to 40[degrees]C temperature range with removal being completely inhibited at 54[degrees]C. The addition of fertilizer to the relatively fresh bed medium used did not increase the rates of gasoline removal in short term experiments. Microbiological analyses indicated that high levels of gasoline degrading microbes are naturally present in the bed medium and that additional inoculation with hydrocarbon degrading cultures does not appreciably increase gasoline removal rates. At lower gasoline concentrations, the vapor removal rates were considerably lower than those at higher gasoline concentrations. This implies that system designs facilitating gasoline transport to the micro-organisms could substantially increase gasoline removal rates at lower gasoline vapor concentrations. Test results from a field scale prototype biofiltration system showed volumetric productivity (i.e., average rate of gasoline degradation per unit bed volume) values that were consistent with those obtained with laboratory column biofilters at similar inlet gasoline concentrations. In addition, total benzene, toluene, ethyl-benzene, and xylene (BTEX) removal over the operating conditions employed was 50 to 55%. Removal of benzene was approximately 10 to 15% and removal of the other members of the BTEX group was much higher, typically >80%.

Tensile test of a silicon microstructure fully coated with submicrometer-thick diamond like carbon film using plasma enhanced chemical vapor deposition method

Science.gov (United States)

Zhang, Wenlei; Uesugi, Akio; Hirai, Yoshikazu; Tsuchiya, Toshiyuki; Tabata, Osamu

2017-06-01

This paper reports the tensile properties of single-crystal silicon (SCS) microstructures fully coated with sub-micrometer thick diamond like carbon (DLC) film using plasma enhanced chemical vapor deposition (PECVD). To minimize the deformations or damages caused by non-uniform coating of DLC, which has high compression residual stress, released SCS specimens with the dimensions of 120 µm long, 4 µm wide, and 5 µm thick were coated from the top and bottom side simultaneously. The thickness of DLC coating is around 150 nm and three different bias voltages were used for deposition. The tensile strength improved from 13.4 to 53.5% with the increasing of negative bias voltage. In addition, the deviation in strength also reduced significantly compared to bare SCS sample.

Atmospheric Pressure Spray Chemical Vapor Deposited CuInS2 Thin Films for Photovoltaic Applications

Science.gov (United States)

Harris, J. D.; Raffaelle, R. P.; Banger, K. K.; Smith, M. A.; Scheiman, D. A.; Hepp, A. F.

2002-01-01

Solar cells have been prepared using atmospheric pressure spray chemical vapor deposited CuInS2 absorbers. The CuInS2 films were deposited at 390 C using the single source precursor (PPh3)2CuIn(SEt)4 in an argon atmosphere. The absorber ranges in thickness from 0.75 - 1.0 micrometers, and exhibits a crystallographic gradient, with the leading edge having a (220) preferred orientation and the trailing edge having a (112) orientation. Schottky diodes prepared by thermal evaporation of aluminum contacts on to the CuInS2 yielded diodes for films that were annealed at 600 C. Solar cells were prepared using annealed films and had the (top down) composition of Al/ZnO/CdS/CuInS2/Mo/Glass. The Jsc, Voc, FF and (eta) were 6.46 mA per square centimeter, 307 mV, 24% and 0.35%, respectively for the best small area cells under simulated AM0 illumination.

Quantifying the Hierarchical Order in Self-Aligned Carbon Nanotubes from Atomic to Micrometer Scale.

Science.gov (United States)

Meshot, Eric R; Zwissler, Darwin W; Bui, Ngoc; Kuykendall, Tevye R; Wang, Cheng; Hexemer, Alexander; Wu, Kuang Jen J; Fornasiero, Francesco

2017-06-27

Fundamental understanding of structure-property relationships in hierarchically organized nanostructures is crucial for the development of new functionality, yet quantifying structure across multiple length scales is challenging. In this work, we used nondestructive X-ray scattering to quantitatively map the multiscale structure of hierarchically self-organized carbon nanotube (CNT) "forests" across 4 orders of magnitude in length scale, from 2.0 Å to 1.5 μm. Fully resolved structural features include the graphitic honeycomb lattice and interlayer walls (atomic), CNT diameter (nano), as well as the greater CNT ensemble (meso) and large corrugations (micro). Correlating orientational order across hierarchical levels revealed a cascading decrease as we probed finer structural feature sizes with enhanced sensitivity to small-scale disorder. Furthermore, we established qualitative relationships for single-, few-, and multiwall CNT forest characteristics, showing that multiscale orientational order is directly correlated with number density spanning 10 9 -10 12 cm -2 , yet order is inversely proportional to CNT diameter, number of walls, and atomic defects. Lastly, we captured and quantified ultralow-q meridional scattering features and built a phenomenological model of the large-scale CNT forest morphology, which predicted and confirmed that these features arise due to microscale corrugations along the vertical forest direction. Providing detailed structural information at multiple length scales is important for design and synthesis of CNT materials as well as other hierarchically organized nanostructures.

Parameterization of water vapor using high-resolution GPS data and empirical models

Science.gov (United States)

Ningombam, Shantikumar S.; Jade, Sridevi; Shrungeshwara, T. S.

2018-03-01

The present work evaluates eleven existing empirical models to estimate Precipitable Water Vapor (PWV) over a high-altitude (4500 m amsl), cold-desert environment. These models are tested extensively and used globally to estimate PWV for low altitude sites (below 1000 m amsl). The moist parameters used in the model are: water vapor scale height (Hc), dew point temperature (Td) and water vapor pressure (Es 0). These moist parameters are derived from surface air temperature and relative humidity measured at high temporal resolution from automated weather station. The performance of these models are examined statistically with observed high-resolution GPS (GPSPWV) data over the region (2005-2012). The correlation coefficient (R) between the observed GPSPWV and Model PWV is 0.98 at daily data and varies diurnally from 0.93 to 0.97. Parameterization of moisture parameters were studied in-depth (i.e., 2 h to monthly time scales) using GPSPWV , Td , and Es 0 . The slope of the linear relationships between GPSPWV and Td varies from 0.073°C-1 to 0.106°C-1 (R: 0.83 to 0.97) while GPSPWV and Es 0 varied from 1.688 to 2.209 (R: 0.95 to 0.99) at daily, monthly and diurnal time scales. In addition, the moist parameters for the cold desert, high-altitude environment are examined in-depth at various time scales during 2005-2012.

Design, development and tests of high-performance silicon vapor chamber

International Nuclear Information System (INIS)

Cai, Qingjun; Chen, Bing-chung; Tsai, Chialun

2012-01-01

This paper presents a novel triple stack process to develop an all-silicon thermal ground plane (TGP) vapor chamber that enables fabrication of compact, large scale, low thermal expansion coefficient mismatch and high-performance heat transfer devices. The TGP vapor chamber is formed through bonding three etched silicon wafers. On both the top and bottom wafers, microscale and high aspect ratio wick structures are etched for liquid transport. The 1.5 mm thick middle layer contains the cavities for vapor flow. To achieve hermetic seal, glass frit with four sealing rings, approximately 300 µm wide and 30 µm thick, is used to bond the edges and supporting posts. For experimental evaluations, 3 mm × 38 mm × 38 mm TGP vapor chambers are developed. The volume density of the heat transfer device is approximately 1.5 × 10 3 kg m −3 . Measurement of mass loss and stability studies of heat transfer indicates that the vapor chamber system is hermetically sealed. Using ethanol as the operating liquid, high heat transfer performance is demonstrated. Effective thermal conductivity reaches over 2500 W m −1  ⋅ K −1 . Under high g environment, experimental results show good liquid transport capabilities of the wick structures. (paper)

Design, development and tests of high-performance silicon vapor chamber

Science.gov (United States)

Cai, Qingjun; Chen, Bing-chung; Tsai, Chialun

2012-03-01

This paper presents a novel triple stack process to develop an all-silicon thermal ground plane (TGP) vapor chamber that enables fabrication of compact, large scale, low thermal expansion coefficient mismatch and high-performance heat transfer devices. The TGP vapor chamber is formed through bonding three etched silicon wafers. On both the top and bottom wafers, microscale and high aspect ratio wick structures are etched for liquid transport. The 1.5 mm thick middle layer contains the cavities for vapor flow. To achieve hermetic seal, glass frit with four sealing rings, approximately 300 µm wide and 30 µm thick, is used to bond the edges and supporting posts. For experimental evaluations, 3 mm × 38 mm × 38 mm TGP vapor chambers are developed. The volume density of the heat transfer device is approximately 1.5 × 103 kg m-3. Measurement of mass loss and stability studies of heat transfer indicates that the vapor chamber system is hermetically sealed. Using ethanol as the operating liquid, high heat transfer performance is demonstrated. Effective thermal conductivity reaches over 2500 W m-1 ṡ K-1. Under high g environment, experimental results show good liquid transport capabilities of the wick structures.

Small-scale variability in tropical tropopause layer humidity

Science.gov (United States)

Jensen, E. J.; Ueyama, R.; Pfister, L.; Karcher, B.; Podglajen, A.; Diskin, G. S.; DiGangi, J. P.; Thornberry, T. D.; Rollins, A. W.; Bui, T. V.; Woods, S.; Lawson, P.

2016-12-01

Recent advances in statistical parameterizations of cirrus cloud processes for use in global models are highlighting the need for information about small-scale fluctuations in upper tropospheric humidity and the physical processes that control the humidity variability. To address these issues, we have analyzed high-resolution airborne water vapor measurements obtained in the Airborne Tropical TRopopause EXperiment over the tropical Pacific between 14 and 20 km. Using accurate and precise 1-Hz water vapor measurements along approximately-level aircraft flight legs, we calculate structure functions spanning horizontal scales ranging from about 0.2 to 50 km, and we compare the water vapor variability in the lower (about 14 km) and upper (16-19 km) Tropical Tropopause Layer (TTL). We also compare the magnitudes and scales of variability inside TTL cirrus versus in clear-sky regions. The measurements show that in the upper TTL, water vapor concentration variance is stronger inside cirrus than in clear-sky regions. Using simulations of TTL cirrus formation, we show that small variability in clear-sky humidity is amplified by the strong sensitivity of ice nucleation rate to supersaturation, which results in highly-structured clouds that subsequently drive variability in the water vapor field. In the lower TTL, humidity variability is correlated with recent detrainment from deep convection. The structure functions indicate approximately power-law scaling with spectral slopes ranging from about -5/3 to -2.

Selective metal-vapor deposition on solvent evaporated polymer surfaces

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Koji; Tsujioka, Tsuyoshi, E-mail: tsujioka@cc.osaka-kyoiku.ac.jp

2015-12-31

We report a selective metal-vapor deposition phenomenon based on solvent printing and evaporation on polymer surfaces and propose a method to prepare fine metal patterns using maskless vacuum deposition. Evaporation of the solvent molecules from the surface caused large free volumes between surface polymer chains and resulted in high mobility of the chains, enhancing metal-vapor atom desorption from the surface. This phenomenon was applied to prepare metal patterns on the polymer surface using solvent printing and maskless metal vacuum deposition. Metal patterns with high resolution of micron scale were obtained for various metal species and semiconductor polymer substrates including poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] and poly(3-hexylthiophene-2,5-diyl). - Highlights: • Selective metal-vapor deposition using solvent evaporation on polymer was attained. • Metal patterns with high resolution were obtained for various metal species. • This method can be applied to achieve fine metal-electrodes for polymer electronics.

Dynamic scaling and kinetic roughening of poly(ethylene) islands grown by vapor phase deposition

Czech Academy of Sciences Publication Activity Database

Choukourov, A.; Melnichuk, I.; Gordeev, I.; Kylián, O.; Hanuš, J.; Kousal, J.; Solař, P.; Hanyková, L.; Brus, Jiří; Slavínská, D.; Biederman, H.

2014-01-01

Roč. 565, 28 August (2014), s. 249-260 ISSN 0040-6090 Institutional support: RVO:61389013 Keywords : poly(ethylene) * physical vapor deposition * island growth Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.759, year: 2014

Enthalpy of vaporization and vapor pressure of whiskey lactone and menthalactone by correlation gas chromatography

International Nuclear Information System (INIS)

Simmons, Daniel; Chickos, James

2017-01-01

Highlights: • The vapor pressure and vaporization enthalpies of cis and trans-whiskey lactone have been evaluated. • Enthalpies of vaporization and vapor pressures of (+)-isomintlactone and (−)-mintlactone were also evaluated. • The sublimation enthalpy and corresponding vapor pressure of (+) -isomintlactone at T = 298.15 K is estimated. - Abstract: Enthalpies of vaporization at T = 298.15 K of cis and trans-whiskey lactone have been evaluated by correlation gas chromatography to be (68.4 ± 1.7) kJ·mol −1 and (67.5 ± 1.7) kJ·mol −1 , respectively. The enthalpies of vaporization of isomintlactone and mintlactone also evaluated by correlation gas chromatography have been found to have vaporization enthalpies of (74.2 ± 1.8) kJ·mol −1 and (73.2 ± 1.8) kJ·mol −1 respectively. The vapor pressures for cis and trans-whiskey lactone at T = 298.15 K have been evaluated as (1.5 ± 0.09) Pa and (2.0 ± 0.1) Pa using vapor pressures of a series of lactones as standards. Vapor pressures for isomintlactone and mintlactone were evaluated as (0.26 ± 0.012) Pa and (0.33 ± 0.02) Pa, respectively. Fusion and sublimation enthalpies for (+)-isomintlactone as well as the vapor pressure of the solid have been estimated.

The preparation and cathodoluminescence of ZnS nanowires grown by chemical vapor deposition

Science.gov (United States)

Huang, Meng-Wen; Cheng, Yin-Wei; Pan, Ko-Ying; Chang, Chen-Chuan; Shieu, F. S.; Shih, Han C.

2012-11-01

Single crystal ZnS nanowires were successfully synthesized in large quantities on Si (1 0 0) substrates by simple thermal chemical vapor deposition without using any catalyst. The morphology, composition, and crystal structure were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and cathodoluminescence (CL) spectroscopy. SEM observations show that the nanowires have diameters about 20-50 nm and lengths up to several tens of micrometers. XRD and TEM results confirmed that the nanowires exhibited both wurtzite and zinc blende structures with growth directions aligned along [0 0 0 2] and [1 1 1], respectively. The CL spectrum revealed emission bands in the UV and blue regions. The blue emissions at 449 and ˜581 nm were attributed to surface states and impurity-related defects of the nanowires, respectively. The perfect crystal structure of the nanowires indicates their potential applications in nanotechnology and in the fabrication of nanodevices.

Controls on water vapor isotopes over Roorkee, India: Impact of convective activities and depression systems

Science.gov (United States)

Saranya, P.; Krishan, Gopal; Rao, M. S.; Kumar, Sudhir; Kumar, Bhishm

2018-02-01

The study evaluates the water vapor isotopic compositions and its controls with special reference to Indian Summer Monsoon (ISM) season at Roorkee, India. Precipitation is usually a discrete event spatially and temporally in this part of the country, therefore, the information provided is limited, while, the vapors have all time availability and have a significant contribution in the hydrological cycle locally or over a regional scale. Hence for understanding the processes altering the various sources, its isotopic signatures were studied. The Isotope Water Vapour Line (Iso Val) was drawn together with the Global Meteoric Water Line (GMWL) and the best fit line was δD = 5.42 * δ18O + 27.86. The precipitation samples were also collected during the study period and were best fitted with δD = 8.20(±0.18) * δ18O + 9.04(±1.16) in the Local Meteoric Water Line (LMWL). From the back trajectory analysis of respective vapor samples, it is unambiguous that three major sources viz; local vapor, western disturbance and monsoon vapor are controlling the fate of moisture over Roorkee. The d-excess in ground-level vapor (GLV) reveals the supply of recycled moisture from continental water bodies and evapo-transpiration as additional moisture sources to the study area. The intensive depletion in isotopic ratios was associated with the large-scale convective activity and low-pressure/cyclonic/depression systems formed over Bay of Bengal.

Experiences of marijuana-vaporizer users.

Science.gov (United States)

Malouff, John M; Rooke, Sally E; Copeland, Jan

2014-01-01

Using a marijuana vaporizer may have potential harm-reduction advantages on smoking marijuana, in that the user does not inhale smoke. Little research has been published on use of vaporizers. In the first study of individuals using a vaporizer on their own initiative, 96 adults anonymously answered questions about their experiences with a vaporizer and their use of marijuana with tobacco. Users identified 4 advantages to using a vaporizer over smoking marijuana: perceived health benefits, better taste, no smoke smell, and more effect from the same amount of marijuana. Users identified 2 disadvantages: inconvenience of setup and cleaning and the time it takes to get the device operating for each use. Only 2 individuals combined tobacco in the vaporizer mix, whereas 15 combined tobacco with marijuana when they smoked marijuana. Almost all participants intended to continue using a vaporizer. Vaporizers seem to have appeal to marijuana users, who perceive them as having harm-reduction and other benefits. Vaporizers are worthy of experimental research evaluating health-related effects of using them.

Biodegradation of vapor-phase toluene in unsaturated porous media: Column experiments

International Nuclear Information System (INIS)

Khan, Ali M.; Wick, Lukas Y.; Harms, Hauke; Thullner, Martin

2016-01-01

Biodegradation of organic chemicals in the vapor phase of soils and vertical flow filters has gained attention as promising approach to clean up volatile organic compounds (VOC). The drivers of VOC biodegradation in unsaturated systems however still remain poorly understood. Here, we analyzed the processes controlling aerobic VOC biodegradation in a laboratory setup mimicking the unsaturated zone above a shallow aquifer. The setup allowed for diffusive vapor-phase transport and biodegradation of three VOC: non-deuterated and deuterated toluene as two compounds of highly differing biodegradability but (nearly) identical physical and chemical properties, and MTBE as (at the applied experimental conditions) non-biodegradable tracer and internal control. Our results showed for toluene an effective microbial degradation within centimeter VOC transport distances despite high gas-phase diffusivity. Degradation rates were controlled by the reactivity of the compounds while oxic conditions were found everywhere in the system. This confirms hypotheses that vadose zone biodegradation rates can be extremely high and are able to prevent the outgassing of VOC to the atmosphere within a centimeter range if compound properties and site conditions allow for sufficiently high degradation rates. - Highlights: • The column setup allows resolving vapor-phase VOC concentration gradients at cm scale resolution. • Vapor-phase and liquid-phase concentrations are measured simultaneously. • Isotopically labelled VOC was used as reference species of low biodegradability. • Biodegradation rates in the unsaturated zone can be very high and act at a cm scale. • Unsaturated material can be an effective bio-barrier avoiding biodegradable VOC emissions. - Microbial degradation activity can be sufficient to remove VOC from unsaturated porous media after a few centimeter of vapor-phase diffusive transport and mayeffectively avoid atmospheric emissions.

Dual vapor extraction on acidic sludge tar at a former refinery

International Nuclear Information System (INIS)

Lear, P.R.; Beall, P.; Townsend, S.

1996-01-01

OHM Remediation Services Corp conducted a pilot-scale demonstration for a novel application of dual vapor extraction technology for the pretreatment of the acid tar sludge material. The acid tar sludge comprised of approximately 60% asphaltene hydrocarbon material, 20% clay, and up to 20% sulfuric acid (H 2 SO 4 ). The liquid layer in the bottom of the pits has a low pH ( 2 ) gas which is released with the sludge material is excavated or handled. The objective of the dual vapor extraction was to remove the SO 2 vapors and liquid layer containing sulfuric acid prior to any further treatment. The dual vapor extraction would reduce the amount of alkaline reagent required for neutralization while eliminating the health and safety concerns. Overall, the DVE pilot demonstration successfully showed that both liquids and vapors could be removed from the acid tar sludge material. The liquid present in the lower portions of the pits will have pH values of 1.0 or less and acidities on the order of 5% H 2 SO 4 . The liquid removed from the acid tar sludge material by a DVE system will have slightly higher pH (∼1.5) and lower alkalinities (∼3% H 2 SO 4 ). The SO 2 concentration in the vapors removed by the DVE system will be variable with initial levels approaching 1,200 ppmv SO 2 . The SO 2 concentration in the vapor phase should decrease with time. A caustic scrubber solution will remove any SO 2 from the vapor phase. After DVE treatment, the acid tar sludge material would have a slightly increased pH and a decreased SO 2 concentration

Rapid Thermal Chemical Vapor Deposition for Dual-Gated Sub-100 nm MOSFET's

National Research Council Canada - National Science Library

Sturm, James

2001-01-01

... (such as microprocessors and memory chips) is based. This project examines the scaling of MOSFET's to very small channel dimensions using a vertical structure which is defined by Rapid Thermal Chemical Vapor Deposition...

Waste Tank Vapor Project: Tank vapor database development

International Nuclear Information System (INIS)

Seesing, P.R.; Birn, M.B.; Manke, K.L.

1994-09-01

The objective of the Tank Vapor Database (TVD) Development task in FY 1994 was to create a database to store, retrieve, and analyze data collected from the vapor phase of Hanford waste tanks. The data needed to be accessible over the Hanford Local Area Network to users at both Westinghouse Hanford Company (WHC) and Pacific Northwest Laboratory (PNL). The data were restricted to results published in cleared reports from the laboratories analyzing vapor samples. Emphasis was placed on ease of access and flexibility of data formatting and reporting mechanisms. Because of time and budget constraints, a Rapid Application Development strategy was adopted by the database development team. An extensive data modeling exercise was conducted to determine the scope of information contained in the database. a A SUN Sparcstation 1000 was procured as the database file server. A multi-user relational database management system, Sybase reg-sign, was chosen to provide the basic data storage and retrieval capabilities. Two packages were chosen for the user interface to the database: DataPrism reg-sign and Business Objects trademark. A prototype database was constructed to provide the Waste Tank Vapor Project's Toxicology task with summarized and detailed information presented at Vapor Conference 4 by WHC, PNL, Oak Ridge National Laboratory, and Oregon Graduate Institute. The prototype was used to develop a list of reported compounds, and the range of values for compounds reported by the analytical laboratories using different sample containers and analysis methodologies. The prototype allowed a panel of toxicology experts to identify carcinogens and compounds whose concentrations were within the reach of regulatory limits. The database and user documentation was made available for general access in September 1994

The vapor pressures of explosives

Energy Technology Data Exchange (ETDEWEB)

Ewing, Robert G.; Waltman, Melanie J.; Atkinson, David A.; Grate, Jay W.; Hotchkiss, Peter

2013-01-05

The vapor pressures of many explosive compounds are extremely low and thus determining accurate values proves difficult. Many researchers, using a variety of methods, have measured and reported the vapor pressures of explosives compounds at single temperatures, or as a function of temperature using vapor pressure equations. There are large variations in reported vapor pressures for many of these compounds, and some errors exist within individual papers. This article provides a review of explosive vapor pressures and describes the methods used to determine them. We have compiled primary vapor pressure relationships traceable to the original citations and include the temperature ranges for which they have been determined. Corrected values are reported as needed and described in the text. In addition, after critically examining the available data, we calculate and tabulate vapor pressures at 25 °C.

Vapor plume oscillation mechanisms in transient keyhole during tandem dual beam fiber laser welding

Science.gov (United States)

Chen, Xin; Zhang, Xiaosi; Pang, Shengyong; Hu, Renzhi; Xiao, Jianzhong

2018-01-01

Vapor plume oscillations are common physical phenomena that have an important influence on the welding process in dual beam laser welding. However, until now, the oscillation mechanisms of vapor plumes remain unclear. This is primarily because mesoscale vapor plume dynamics inside a millimeter-scale, invisible, and time-dependent keyhole are difficult to quantitatively observe. In this paper, based on a developed three-dimensional (3D) comprehensive model, the vapor plume evolutions in a dynamical keyhole are directly simulated in tandem dual beam, short-wavelength laser welding. Combined with the vapor plume behaviors outside the keyhole observed by high-speed imaging, the vapor plume oscillations in dynamical keyholes at different inter-beam distances are the first, to our knowledge, to be quantitatively analyzed. It is found that vapor plume oscillations outside the keyhole mainly result from vapor plume instabilities inside the keyhole. The ejection velocity at the keyhole opening and dynamical behaviors outside the keyhole of a vapor plume both violently oscillate with the same order of magnitude of high frequency (several kHz). Furthermore, the ejection speed at the keyhole opening and ejection area outside the keyhole both decrease as the beam distance increases, while the degree of vapor plume instability first decreases and then increases with increasing beam distance from 0.6 to 1.0 mm. Moreover, the oscillation mechanisms of a vapor plume inside the dynamical keyhole irradiated by dual laser beams are investigated by thoroughly analyzing the vapor plume occurrence and flow process. The vapor plume oscillations in the dynamical keyhole are found to mainly result from violent local evaporations and severe keyhole geometry variations. In short, the quantitative method and these findings can serve as a reference for further understanding of the physical mechanisms in dual beam laser welding and of processing optimizations in industrial applications.

Temperature Sensitivity of an Atomic Vapor Cell-Based Dispersion-Enhanced Optical Cavity

Science.gov (United States)

Myneni, K.; Smith, D. D.; Chang, H.; Luckay, H. A.

2015-01-01

Enhancement of the response of an optical cavity to a change in optical path length, through the use of an intracavity fast-light medium, has previously been demonstrated experimentally and described theoretically for an atomic vapor cell as the intracavity resonant absorber. This phenomenon may be used to enhance both the scale factor and sensitivity of an optical cavity mode to the change in path length, e.g. in gyroscopic applications. We study the temperature sensitivity of the on-resonant scale factor enhancement, S(sub o), due to the thermal sensitivity of the lower-level atom density in an atomic vapor cell, specifically for the case of the Rb-87 D(sub 2) transition. A semi-empirical model of the temperature-dependence of the absorption profile, characterized by two parameters, a(sub o)(T) and gamma(sub a)(T) allows the temperature-dependence of the cavity response, S(sub o)(T) and dS(sub o)/dT to be predicted over a range of temperature. We compare the predictions to experiment. Our model will be useful in determining the useful range for S(sub o), given the practical constraints on temperature stability for an atomic vapor cell.

A Fundamental Study of Gas and Vapor Bubble Dynamics in Micro-Channels

National Research Council Canada - National Science Library

Prosperetti, Andrea

1999-01-01

The aim of this project was to carry out a fundamental study of the basic: Physics underlying the applications of gas and vapor bubbles in heat transfer systems, pumps, actuators, and other small-scale systems...

Oxidation Kinetics of Chemically Vapor-Deposited Silicon Carbide in Wet Oxygen

Science.gov (United States)

Opila, Elizabeth J.

1994-01-01

The oxidation kinetics of chemically vapor-deposited SiC in dry oxygen and wet oxygen (P(sub H2O) = 0.1 atm) at temperatures between 1200 C and 1400 C were monitored using thermogravimetric analysis. It was found that in a clean environment, 10% water vapor enhanced the oxidation kinetics of SiC only very slightly compared to rates found in dry oxygen. Oxidation kinetics were examined in terms of the Deal and Grove model for oxidation of silicon. It was found that in an environment containing even small amounts of impurities, such as high-purity Al2O3 reaction tubes containing 200 ppm Na, water vapor enhanced the transport of these impurities to the oxidation sample. Oxidation rates increased under these conditions presumably because of the formation of less protective sodium alumino-silicate scales.

Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

Science.gov (United States)

McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.; Bender, Steve; Lemmon, Mark; Wiens, Roger C.; Maurice, Sylvestre; Gasnault, Olivier; Lasue, Jeremie; Meslin, Pierre-Yves; Harri, Ari-Matti; Genzer, Maria; Kemppinen, Osku; Martínez, Germán M.; DeFlores, Lauren; Blaney, Diana; Johnson, Jeffrey R.; Bell, James F.

2018-06-01

We derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 Ls = 291° (March 30, 2013) to Mars Year 33 Ls= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model, using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO2 absorptions and the known CO2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large scale circulations and thus

Building blocks for ionic liquids: Vapor pressures and vaporization enthalpies of 1-(n-alkyl)-imidazoles

International Nuclear Information System (INIS)

Emel'yanenko, Vladimir N.; Portnova, Svetlana V.; Verevkin, Sergey P.; Skrzypczak, Andrzej; Schubert, Thomas

2011-01-01

Highlights: → We measured vapor pressures of the 1-(n-alkyl)-imidazoles by transpiration method. → Variations on the alkyl chain length n were C 3 , C 5 -C 7 , and C 9 -C 10 . → Enthalpies of vaporization were derived from (p, T) dependencies. → Enthalpies of vaporization at 298.15 K were linear dependent on the chain length. - Abstract: Vapor pressures of the linear 1-(n-alkyl)-imidazoles with the alkyl chain C 3 , C 5 -C 7 , and C 9 -C 10 have been measured by the transpiration method. The molar enthalpies of vaporization Δ l g H m of these compounds were derived from the temperature dependencies of vapor pressures. A linear correlation of enthalpies of vaporization Δ l g H m (298.15 K) of the 1-(n-alkyl)-imidazoles with the chain length has been found.

Vapor pressure and enthalpy of vaporization of oil of catnip by correlation gas chromatography

International Nuclear Information System (INIS)

Simmons, Daniel; Gobble, Chase; Chickos, James

2016-01-01

Highlights: • Vaporization enthalpies of the nepetalactones from oil of catnip have been evaluated. • Vapor pressures from T = (298.15 to 350) K have been evaluated. • Oil of catnip has a vapor pressure similar to DEET at T = 298.15 K. - Abstract: The vaporization enthalpy and vapor pressure of the two nepetalactones found in Nepeta cataria have been evaluated by correlation gas chromatography. Vaporization enthalpies at T = 298.15 K of {(68.0 ± 1.9) and (69.4 ± 1.9)} kJ ⋅ mol"−"1 have been derived for the minor diastereomer, (4aS,7S,7aS)-nepetalactone, and major one, (4aS,7S,7aR)-nepetalactone, respectively. Vapor pressures also at T = 298.15 K of p = (1.2 ± 0.04) Pa and (0.91 ± 0.03) Pa have been evaluated for the minor and the major stereoisomer. In addition to being of interest because of the remarkable effect it has on various felids, oil of catnip is also quite effective in repelling mosquitoes, comparable to diethyl-m-toluamide (DEET). The vapor pressures evaluated in this work suggest that the two stereoisomers have similar volatility to DEET at ambient temperatures.

Sub-micrometer-thick all-solid-state supercapacitors with high power and energy densities

Energy Technology Data Exchange (ETDEWEB)

Meng, Fanhui [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, and School of Chemistry and Chemical Engineering, Shandong University, Jinan 250061 (China); Ding, Yi [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, and School of Chemistry and Chemical Engineering, Shandong University, Jinan 250061 (China); Shandong Applied Research Center for Gold Technology (Au-SDARC), Yantai 264005 (China)

2011-09-15

A sub-micrometer-thick, flexible, all-solid-state supercapacitor is fabricated. Through simultaneous realization of high dispersity of pseudocapacitance materials and quick electrode response, the hybrid nanostructures show enhanced volumetric capacitance and excellent stability, as well as very high power and energy densities. This suggests their potential as next-generation, high-performance energy conversion and storage devices for wearable electronics. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Dislocation confinement in the growth of Na flux GaN on metalorganic chemical vapor deposition-GaN

International Nuclear Information System (INIS)

Takeuchi, S.; Asazu, H.; Nakamura, Y.; Sakai, A.; Imanishi, M.; Imade, M.; Mori, Y.

2015-01-01

We have demonstrated a GaN growth technique in the Na flux method to confine c-, (a+c)-, and a-type dislocations around the interface between a Na flux GaN crystal and a GaN layer grown by metalorganic chemical vapor deposition (MOCVD) on a (0001) sapphire substrate. Transmission electron microscopy (TEM) clearly revealed detailed interface structures and dislocation behaviors that reduced the density of vertically aligned dislocations threading to the Na flux GaN surface. Submicron-scale voids were formed at the interface above the dislocations with a c component in MOCVD-GaN, while no such voids were formed above the a-type dislocations. The penetration of the dislocations with a c component into Na flux GaN was, in most cases, effectively blocked by the presence of the voids. Although some dislocations with a c component in the MOCVD-GaN penetrated into the Na flux GaN, their propagation direction changed laterally through the voids. On the other hand, the a-type dislocations propagated laterally and collectively near the interface, when these dislocations in the MOCVD-GaN penetrated into the Na flux GaN. These results indicated that the dislocation propagation behavior was highly sensitive to the type of dislocation, but all types of dislocations were confined to within several micrometers region of the Na flux GaN from the interface. The cause of void formation, the role of voids in controlling the dislocation behavior, and the mechanism of lateral and collective dislocation propagation are discussed on the basis of TEM results

Vapor pressures and vaporization enthalpy of (−) α-bisabolol and (dl) menthol by correlation gas chromatography

International Nuclear Information System (INIS)

Keating, Leasa; Harris, Harold H.; Chickos, James S.

2017-01-01

Highlights: • The vaporization enthalpy and vapor pressure of (−) α-bisabolol and (dl)-menthol have been measured as a function of temperature. • Vapor pressures, vaporization enthalpies and boiling temperatures have been compared to available literature data. • Vapor pressures of (l)-menthol are compared to (dl)-menthol. - Abstract: The vapor pressures and vaporization enthalpies of (−) α-bisabolol and (dl)-menthol, two GRAS chemicals (generally recognized as safe) are evaluated by correlation gas chromatography using a series of saturated primary alcohols as standards. Vaporization enthalpies of (96.6 ± 2.4) and (74.2 ± 2.8) kJ mol −1 and vapor pressures of p/Pa = (0.020 ± 0.003) and (4.5 ± 0.44) were evaluated at T = 298.15 K for (−) α-bisabolol and (dl)-menthol, respectively, and compared to literature values. The vapor pressures of both compounds from T = (298.15 to 500) K have been derived from correlations using vapor pressures of a series of 1-alkanols and corresponding gas chromatographic retention times at 10 K intervals. The results were fit to a second order polynomial. Calculated normal boiling temperatures of T B = (574.8 and 492.7) K are calculated for (−) α-bisabolol and (dl)-menthol, respectively. A normal boiling temperature of T B = (485.2, and 489.7) K has previously been reported for (dl)-menthol. Vapor pressures for both (l)-menthol and (dl)-menthol from a previous study and (dl)-menthol from this study are compared with literature values.

Melting temperature, vapor density, and vapor pressure of molybdenum pentafluoride

Energy Technology Data Exchange (ETDEWEB)

Krause, Jr, R F; Douglas, T B [National Bureau of Standards, Washington, D.C. (USA). Inst. for Materials Research

1977-12-01

A sample of MoF/sub 5/ was prepared by reaction of MoF/sub 6/(g) and Mo(c). Melting curves of temperature against time established the melting temperature at zero impurity to be 318.85 K, the enthalpy of fusion to be 6.1 kJ mol/sup -1/ (+ - 5 per cent), and the cryoscopic impurity of the sample to be 0.15 mole per cent. In the presence of MoF/sub 6/(g) which was added to suppress disproportionation, the vapor density of MoF/sub 5/ over the liquid was measured by the transpiration method at 343, 363, and 383 K, the total MoF/sub 5/ that evaporated being determined by permanganate titration. The total vapor pressure of MoF/sub 5/ oligomers over the liquid was measured by a simple static method at 373 and 392 K, while melting temperatures were taken alternately to monitor possible contamination of the sample. Although the vapor pressures were adjusted for disproportionation, solution of MoF/sub 6/ in MoF/sub 5/ (1), and wall adsorption of MoF/sub 6/ their percentage uncertainty is probably several times that of the vapor densities. A combination of the two properties indicates the average extent of association of the saturated vapor to be near 2, which is the value for the dimer species (MoF/sub 5/)/sub 2/.

Investigation on energetics of ex-vessel vapor explosion based on spontaneous nucleation fragmentation

International Nuclear Information System (INIS)

Liu, Jie; Koshizuka, Seiichi; Oka, Yoshiaki

2002-01-01

A computer code PROVER-I is developed for propagation phase of vapor explosion. A new thermal fragmentation model is proposed with three kinds of time scale for modeling instant fragmentation, spontaneous nucleation fragmentation and normal boiling fragmentation. The energetics of ex-vessel vapor explosion is investigated based on different fragmentation models. A higher pressure peak and a larger mechanical energy conversion ratio are obtained by spontaneous nucleation fragmentation. A smaller energy conversion ratio results from normal boiling fragmentation. When the delay time in thermal fragmentation model is near 0.0 ms, the pressure propagation behavior tends to be analogous with that in hydrodynamic fragmentation. If the delay time is longer, pressure attenuation occurs at the shock front. The high energy conversion ratio (>4%) is obtained in a small vapor volume fraction together with spontaneous nucleation fragmentation. These results are consistent with fuel-coolant interaction experiments with alumina melt. However, in larger vapor volume fraction conditions (α υ >0.3), the vapor explosion is weak. For corium melt, a coarse mixture with void fraction of more than 30% can be generated in the pre-mixing process because of its physical properties. In the mixture with such a high void fraction the energetic vapor explosion hardly takes place. (author)

Upper limits to trace constituents in Jupiter's atmosphere from an analysis of its 5 micrometer spectrum

Science.gov (United States)

Treffers, R. R.; Larson, H. P.; Fink, U.; Gautier, T. N.

1978-01-01

A high-resolution spectrum of Jupiter at 5 micrometers recorded at the Kuiper Airborne Observatory is used to determine upper limits to the column density of 19 molecules. The upper limits to the mixing ratios of SiH4, H2S, HCN, and simple hydrocarbons are discussed with respect to current models of Jupiter's atmosphere. These upper limits are compared to expectations based upon the solar abundance of the elements. This analysis permits upper limit measurements (SiH4), or actual detections (GeH4) of molecules with mixing ratios with hydrogen as low as 10 to the minus 9th power. In future observations at 5 micrometers the sensitivity of remote spectroscopic analyses should permit the study of constituents with mixing ratios as low as 10 to the minus 10th power, which would include the hydrides of such elements as Sn and As as well as numerous organic molecules.

Micrometer-scale magnetic imaging of geological samples using a quantum diamond microscope

Science.gov (United States)

Glenn, D. R.; Fu, R. R.; Kehayias, P.; Le Sage, D.; Lima, E. A.; Weiss, B. P.; Walsworth, R. L.

2017-08-01

Remanent magnetization in geological samples may record the past intensity and direction of planetary magnetic fields. Traditionally, this magnetization is analyzed through measurements of the net magnetic moment of bulk millimeter to centimeter sized samples. However, geological samples are often mineralogically and texturally heterogeneous at submillimeter scales, with only a fraction of the ferromagnetic grains carrying the remanent magnetization of interest. Therefore, characterizing this magnetization in such cases requires a technique capable of imaging magnetic fields at fine spatial scales and with high sensitivity. To address this challenge, we developed a new instrument, based on nitrogen-vacancy centers in diamond, which enables direct imaging of magnetic fields due to both remanent and induced magnetization, as well as optical imaging, of room-temperature geological samples with spatial resolution approaching the optical diffraction limit. We describe the operating principles of this device, which we call the quantum diamond microscope (QDM), and report its optimized image-area-normalized magnetic field sensitivity (20 µTṡµm/Hz1/2), spatial resolution (5 µm), and field of view (4 mm), as well as trade-offs between these parameters. We also perform an absolute magnetic field calibration for the device in different modes of operation, including three-axis (vector) and single-axis (projective) magnetic field imaging. Finally, we use the QDM to obtain magnetic images of several terrestrial and meteoritic rock samples, demonstrating its ability to resolve spatially distinct populations of ferromagnetic carriers.

SPADE H2O measurements and the seasonal cycle of statospheric water vapor

Science.gov (United States)

Hintsa, Eric J.; Weinstock, Elliot M.; Dessler, Andrew E.; Anderson, James G.; Loewenstein, Max; Podolske, James R.

1994-01-01

We present measurements of lower statospheric water vapor obtained during the Stratospheric Phototchemistry, Aerosols and Dynamics Expedition (SPADE) mission with a new high precision, fast response, Lyman-alpha hygrometer. The H2O data show a distinct seasonal cycle. For air that recently entered the statosphere, data collected during the fall show much more water vapor than data from the spring. Fast quasi-horizontal mixing causes compact relationships between water and N2O to be established on relatively short time scales. The measurements are consistent with horizontal mixing times of a few months or less. Vertical mixing appears to cause the seasonal variations in water vapor to propagate up to levels corresponding to air that has been in the stratosphere approximately one year.

Plasma-polymerized films providing selective affinity to the polarity of vaporized organic solvents

International Nuclear Information System (INIS)

Akimoto, Takuo; Ikeshita, Yusuke; Terashima, Ryo; Karube, Isao

2009-01-01

Plasma-polymerized films (PPFs) were fabricated as recognition membranes for a vapor-sensing device, and their affinity to vaporized organic solvents was evaluated with surface plasmon resonance. The affinity we intended to create is the selective sorption of the vaporized organic solvents depending on their polarity. For this purpose, acetonitrile, ethylenediamine (EDA), styrene, hexamethyldisiloxane (HMDSO), and hexamethyldisilazane were used to fabricate PPFs. Vaporized methanol, ethanol, and 1-propanol were used as high-polar solvents to be analyzed. Hexane, toluene, and p-xylene were used as low-polar solvents. As a result, the HMDSO-PPF with 97.3 o of contact angle was found to provide affinity to the low-polar solvents. In contrast, the EDA-PPF with 7.1 o of contact angle provided affinity to the high-polar solvents. Observations of the surface morphology of the HMDSO- and EDA-PPFs with a scanning electron microscope revealed that they are composed of nano-scale islands.

Piezoelectric trace vapor calibrator

International Nuclear Information System (INIS)

Verkouteren, R. Michael; Gillen, Greg; Taylor, David W.

2006-01-01

The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10 deg. C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver--on demand--continuous vapor concentrations across more than six orders of magnitude (nominally 290 fg/l to 1.05 μg/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process

Laser chemical vapor deposition of millimeter scale three-dimensional shapes

Science.gov (United States)

Shaarawi, Mohammed Saad

2001-07-01

Laser chemical vapor deposition (LCVD) has been successfully developed as a technique to synthesize millimeter-scale components directly from the gas phase. Material deposition occurs when heat generated by the interaction of a laser beam with a substrate thermally decomposes the gas precursor. Selective illumination or scanning the laser beam over portions of a substrate forms the single thin layer of material that is the building block of this process. Sequential scanning of the laser in a pre-defined pattern on the substrate and subsequent deposit causes the layers to accumulate forming the three-dimensional shape. The primary challenge encountered in LCVD shape forming is the synthesis of uniform layers. Three deposition techniques are studied to address this problem. The most successful technique, Active Surface Deposition, is based on the premise that the most uniform deposits are created by measuring the deposition surface topology and actively varying the deposition rate in response to features at the deposition surface. Defects observed in the other techniques were significantly reduced or completely eliminated using Active Surface Deposition. The second technique, Constant Temperature Deposition, maintains deposit uniformity through the use of closed-loop modulation of the laser power to sustain a constant surface temperature during deposition. The technique was successful in depositing high quality graphite tubes >2 mm tall from an acetylene precursor and partially successful in depositing SiC + C composite tubes from tetramethylsilane (TMS). The final technique, Constant Power Deposition, is based on the premise that maintaining a uniform power output throughout deposition would result in the formation of uniform layers. Constant Power Deposition failed to form coherent shapes. Additionally, LCVD is studied using a combination of analytic and numerical models to gain insight into the deposition process. Thermodynamic modeling is used to predict the

Fuel vapor pressure (FVAPRS)

International Nuclear Information System (INIS)

Mason, R.E.

1979-04-01

A subcode (FVAPRS) is described which calculates fuel vapor pressure. This subcode was developed as part of the fuel rod behavior modeling task performed at EG and G Idaho, Inc. The fuel vapor pressure subcode (FVAPRS), is presented and a discussion of literature data, steady state and transient fuel vapor pressure equations and estimates of the standard error of estimate to be expected with the FVAPRS subcode are included

Large Scale Tests of Vaporous Hydrogen Peroxide (VHP(Register Trademark)) for Chemical and Biological Weapons Decontamination

National Research Council Canada - National Science Library

Wagner, George; Procell, Larry; Sorrick, David; Maclver, Brian; Turetsky, Abe; Pfarr, Jerry; Dutt, Diane; Brickhouse, Mark

2004-01-01

Vaporous Hydrogen Peroxide (VHP) has been used for more than a decade to sterilize clean rooms and pharmaceutical processing equipment and, more recently, to decontaminate anthraxcontaminated buildings...

Contact area of rough spheres: Large scale simulations and simple scaling laws

Energy Technology Data Exchange (ETDEWEB)

Pastewka, Lars, E-mail: lars.pastewka@kit.edu [Institute for Applied Materials & MicroTribology Center muTC, Karlsruhe Institute of Technology, Engelbert-Arnold-Straße 4, 76131 Karlsruhe (Germany); Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218 (United States); Robbins, Mark O., E-mail: mr@pha.jhu.edu [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218 (United States)

2016-05-30

We use molecular simulations to study the nonadhesive and adhesive atomic-scale contact of rough spheres with radii ranging from nanometers to micrometers over more than ten orders of magnitude in applied normal load. At the lowest loads, the interfacial mechanics is governed by the contact mechanics of the first asperity that touches. The dependence of contact area on normal force becomes linear at intermediate loads and crosses over to Hertzian at the largest loads. By combining theories for the limiting cases of nominally flat rough surfaces and smooth spheres, we provide parameter-free analytical expressions for contact area over the whole range of loads. Our results establish a range of validity for common approximations that neglect curvature or roughness in modeling objects on scales from atomic force microscope tips to ball bearings.

Contact area of rough spheres: Large scale simulations and simple scaling laws

Science.gov (United States)

Pastewka, Lars; Robbins, Mark O.

2016-05-01

We use molecular simulations to study the nonadhesive and adhesive atomic-scale contact of rough spheres with radii ranging from nanometers to micrometers over more than ten orders of magnitude in applied normal load. At the lowest loads, the interfacial mechanics is governed by the contact mechanics of the first asperity that touches. The dependence of contact area on normal force becomes linear at intermediate loads and crosses over to Hertzian at the largest loads. By combining theories for the limiting cases of nominally flat rough surfaces and smooth spheres, we provide parameter-free analytical expressions for contact area over the whole range of loads. Our results establish a range of validity for common approximations that neglect curvature or roughness in modeling objects on scales from atomic force microscope tips to ball bearings.

Constraining the 0-20 km Vertical Profile of Water Vapor in the Martian Atmosphere with MGS-TES Limb Sounding

Science.gov (United States)

McConnochie, T. H.; Smith, M. D.; McDonald, G. D.

2016-12-01

The vertical profile of water vapor in the lower atmosphere of Mars is a crucial but poorly-measured detail of the water cycle. Most of our existing water vapor data sets (e.g. Smith, 2002, JGR 107; Smith et al., 2009, JGR 114; Maltagliati et al., 2011, Icarus 213) rely on the traditional assumption of uniform mass mixing from the surface up to a saturation level, but GCM models (Richardson et al., 2002, JGR 107; Navarro et al., 2014, JGR 119) imply that this is not the case in at least some important seasons and locations. For example at the equator during northern summer the water vapor mixing ratio in aforementioned GCMs increases upwards by a factor of two to three in the bottom scale height. This might influence the accuracy of existing precipitable water column (PWC) data sets. Even if not, the correct vertical distribution is critical for determining the extent to which high-altitude cold trapping interferes with inter-hemispheric transport, and its details in the lowest scale heights will be a critical test of the accuracy of modeled water vapor transport. Meanwhile attempts to understand apparent interactions of water vapor with surface soils (e.g. Ojha et al. 2015, Nature Geoscience 8; Savijärvi et al., 2016, Icarus 265) need an estimate for the amount of water vapor in the boundary layer, and existing PWC data sets can't provide this unless the lower atmospheric vertical distribution is known or constrained. Maltagliati et al. (2013, Icarus 223) have obtained vertical profiles of water vapor at higher altitudes with SPICAM on Mars Express, but these are commonly limited to altitudes greater 20 km and they never extend below 10 km. We have previously used Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) limb-sounding to measure the vertical profile of water vapor (e.g. McConnochie and Smith, 2009, Fall AGU #P54B-06), but these preliminary results were clearly not quantitatively accurate in the lower atmosphere. We will present improved TES

Production and Characterisation of SLID Interconnected n-in-p Pixel Modules with 75 Micrometer Thin Silicon Sensors

CERN Document Server

Andricek, L; Macchiolo, A.; Moser, H.-G.; Nisius, R.; Richter, R.H.; Terzo, S.; Weigell, P.

2014-01-01

The performance of pixel modules built from 75 micrometer thin silicon sensors and ATLAS read-out chips employing the Solid Liquid InterDiffusion (SLID) interconnection technology is presented. This technology, developed by the Fraunhofer EMFT, is a possible alternative to the standard bump-bonding. It allows for stacking of different interconnected chip and sensor layers without destroying the already formed bonds. In combination with Inter-Chip-Vias (ICVs) this paves the way for vertical integration. Both technologies are combined in a pixel module concept which is the basis for the modules discussed in this paper. Mechanical and electrical parameters of pixel modules employing both SLID interconnections and sensors of 75 micrometer thickness are covered. The mechanical features discussed include the interconnection efficiency, alignment precision and mechanical strength. The electrical properties comprise the leakage currents, tunability, charge collection, cluster sizes and hit efficiencies. Targeting at ...

NASA Experiment on Tropospheric-Stratospheric Water Vapor Transport in the Intertropical Convergence Zone

Science.gov (United States)

Page, William A.

1982-01-01

The following six papers report preliminary results obtained from a field experiment designed to study the role of tropical cumulo-nimbus clouds in the transfer of water vapor from the troposphere to the stratosphere over the region of Panama. The measurements were made utilizing special NOAA enhanced IR satellite images, radiosonde-ozonesondes and a NASA U-2 aircraft carrying. nine experiments. The experiments were provided by a group of NASA, NOAA, industry, and university scientists. Measurements included atmospheric humidity, air and cloud top temperatures, atmospheric tracer constituents, cloud particle characteristics and cloud morphology. The aircraft made a total of eleven flights from August 30 through September 18, 1980, from Howard Air Force Base, Panama; the pilots obtained horizontal and vertical profiles in and near convectively active regions and flew around and over cumulo-nimbus towers and through the extended anvils in the stratosphere. Cumulo-nimbus clouds in the tropics appear to play an important role in upward water vapor transport and may represent the principal source influencing the stratospheric water vapor budget. The clouds provide strong vertical circulation in the troposphere, mixing surface air and its trace materials (water vapor, CFM's sulfur compounds, etc.) quickly up to the tropopause. It is usually assumed that large scale mean motions or eddy scale motions transport the trace materials through the tropopause and into the stratosphere where they are further dispersed and react with other stratospheric constituents. The important step between the troposphere and stratosphere for water vapor appears to depend upon the processes occurring at or near the tropopause at the tops of the cumulo-nimbus towers. Several processes have been sugested: (1) The highest towers penetrate the tropopause and carry water in the form of small ice particles directly into the stratosphere. (2) Water vapor from the tops of the cumulonimbus clouds is

Vapor generation methods for explosives detection research

Energy Technology Data Exchange (ETDEWEB)

Grate, Jay W.; Ewing, Robert G.; Atkinson, David A.

2012-12-01

The generation of calibrated vapor samples of explosives compounds remains a challenge due to the low vapor pressures of the explosives, adsorption of explosives on container and tubing walls, and the requirement to manage (typically) multiple temperature zones as the vapor is generated, diluted, and delivered. Methods that have been described to generate vapors can be classified as continuous or pulsed flow vapor generators. Vapor sources for continuous flow generators are typically explosives compounds supported on a solid support, or compounds contained in a permeation or diffusion device. Sources are held at elevated isothermal temperatures. Similar sources can be used for pulsed vapor generators; however, pulsed systems may also use injection of solutions onto heated surfaces with generation of both solvent and explosives vapors, transient peaks from a gas chromatograph, or vapors generated by s programmed thermal desorption. This article reviews vapor generator approaches with emphasis on the method of generating the vapors and on practical aspects of vapor dilution and handling. In addition, a gas chromatographic system with two ovens that is configurable with up to four heating ropes is proposed that could serve as a single integrated platform for explosives vapor generation and device testing. Issues related to standards, calibration, and safety are also discussed.

Isotopic equilibrium between precipitation and water vapor: evidence from continental rains in central Kenya

Science.gov (United States)

Soderberg, K.; Gerlein, C.; Kemeny, P. C.; Caylor, K. K.

2013-12-01

An accurate understanding of the relationships between the isotopic composition of liquid water and that of water vapor in the environment can help describe hydrologic processes across many scales. One such relationship is the isotopic equilibrium between falling raindrops and the surrounding vapor. The degree of equilibration is used to model the isotopic composition of precipitation in isotope-enable general circulation models and land-atmosphere exchange models. Although this equilibrium has been a topic of isotope hydrology research for more than four decades, few studies have included vapor measurements to validate modeling efforts. Recent advances in laser technology have allowed for in situ vapor measurements at high temporal resolution (e.g., >1 Hz). Here we present concomitant rain and vapor measurements for a series of 17 rain events during the 'Continental' rainy season (June through August) at Mpala Research Center in central Kenya. Rain samples (n=218) were collected at intervals of 2 to 35 minutes (median of 3 minutes) depending on the rain rate (0.4 to 10.5 mm/hr). The volume-weighted mean rain values for δ18O, δ2H and D-excess (δ2H - 8* δ18O) were 0.1 ‰, 10.7 ‰, and 10.1 ‰. These values are more enriched than the annual weighted means reported for the area (-2.2 ‰, -7.6 ‰, and 11.0 ‰, respectively). Vapor was measured continuously at ~2Hz (DLT-100, Los Gatos Research), with an inverted funnel intake 4m above the ground surface. The mean vapor isotopic composition during the rain events was -10.0 +/- 1.2 ‰ (1 σ) for δ18O and -73.9 +/- 7.0 ‰ for δ2H. The difference between the rain sample isotopic composition and that of liquid in isotopic equilibrium with the corresponding vapor at the ambient temperature was 0.8 +/- 2.2 ‰ for δ18O and 6.2 +/- 7.0 ‰ for δ2H. This disequilibrium was found to correlate with the natural log of rain rate (R2 of 0.26 for δ18O and 0.46 for δ2H), with lower rain rates having larger

The effect of global-scale divergent circulation on the atmospheric water vapor transport and maintenance

Science.gov (United States)

Chen, Tsing-Chang

1988-01-01

The detection, distribution, and dynamics of atmospheric water on Earth was examined. How the high levels of water vapor and precipitation that occur over the tropics during the monsoon season result from the development of a strong divergent atmospheric circulation is discussed.

Synthesis and characterization of magnetic and non-magnetic core-shell polyepoxide micrometer-sized particles of narrow size distribution.

Science.gov (United States)

Omer-Mizrahi, Melany; Margel, Shlomo

2009-01-15

Core polystyrene microspheres of narrow size distribution were prepared by dispersion polymerization of styrene in a mixture of ethanol and 2-methoxy ethanol. Uniform polyglycidyl methacrylate/polystyrene core-shell micrometer-sized particles were prepared by emulsion polymerization at 73 degrees C of glycidyl methacrylate in the presence of the core polystyrene microspheres. Core-shell particles with different properties (size, surface morphology and composition) have been prepared by changing various parameters belonging to the above seeded emulsion polymerization process, e.g., volumes of the monomer glycidyl methacrylate and the crosslinker monomer ethylene glycol dimethacrylate. Magnetic Fe(3)O(4)/polyglycidyl methacrylate/polystyrene micrometer-sized particles were prepared by coating the former core-shell particles with magnetite nanoparticles via a nucleation and growth mechanism. Characterization of the various particles has been accomplished by routine methods such as light microscopy, SEM, FTIR, BET and magnetic measurements.

The vaporization enthalpy and vapor pressure of S (+)-methamphetamine at T = 298.15 K by correlation gas chromatography

International Nuclear Information System (INIS)

Thornton, Melissa; Gobble, Chase; Chickos, James

2014-01-01

Highlights: • The vaporization enthalpy of (d)-methamphetamine was measured. • The vapor pressure of (d)-methamphetamine as a function of temperature was evaluated. • The vapor pressure of 4-benzylpiperidine as a function of temperature was evaluated. - Abstract: The vaporization enthalpy and vapor pressure of S (+)-methamphetamine is evaluated by correlation-gas chromatography. A vaporization enthalpy of (58.7 ± 4.3) kJ · mol −1 and a vapor pressure, p = (38 ± 9) Pa has been obtained using a variety of secondary aliphatic amines as standards. In addition, equations describing the vapor pressure temperature dependence are provided for standards and S (+)-methamphetamine covering the temperature range from T = 298.15 K to the boiling temperature. Boiling temperatures are reproduced within an interval of 8 K or less

Observation and particle simulation of vaporized W, Mo, and Be in PISCES-B plasma for vapor-shielding studies

Directory of Open Access Journals (Sweden)

K. Ibano

2017-08-01

Full Text Available Interactions of Tungsten (W, Molybdenum (Mo, and Beryllium (Be vapors with a steady-state plasma were studied by the PISCES-B liner plasma experiments as well as Particle-In-Cell (PIC simulations for the understanding of vapor-shielding phenomena. Effective cooling of the plasma by laser-generated Be vapor was observed in PISCES-B. On the other hand, no apparent cooling was observed for W and Mo vapors. The PIC simulation explains these experimental observations of the difference between low-Z and high-Z vapors. Decrease of electron temperature due to the vapor ejection was observed in case of a simulation of the Be vapor. As for the W vapor, it was found that the plasma cooling is localized only near the wall at a higher electron density plasma (∼1019m−3. On the other hand, the appreciable plasma cooling can be observed in a lower density plasma (∼1018m−3 for the W vapor.

Passive vapor extraction feasibility study

International Nuclear Information System (INIS)

Rohay, V.J.

1994-01-01

Demonstration of a passive vapor extraction remediation system is planned for sites in the 200 West Area used in the past for the disposal of waste liquids containing carbon tetrachloride. The passive vapor extraction units will consist of a 4-in.-diameter pipe, a check valve, a canister filled with granular activated carbon, and a wind turbine. The check valve will prevent inflow of air that otherwise would dilute the soil gas and make its subsequent extraction less efficient. The granular activated carbon is used to adsorb the carbon tetrachloride from the air. The wind turbine enhances extraction rates on windy days. Passive vapor extraction units will be designed and operated to meet all applicable or relevant and appropriate requirements. Based on a cost analysis, passive vapor extraction was found to be a cost-effective method for remediation of soils containing lower concentrations of volatile contaminants. Passive vapor extraction used on wells that average 10-stdft 3 /min air flow rates was found to be more cost effective than active vapor extraction for concentrations below 500 parts per million by volume (ppm) of carbon tetrachloride. For wells that average 5-stdft 3 /min air flow rates, passive vapor extraction is more cost effective below 100 ppm

Absolute distance measurement with micrometer accuracy using a Michelson interferometer and the iterative synthetic wavelength principle.

Science.gov (United States)

Alzahrani, Khaled; Burton, David; Lilley, Francis; Gdeisat, Munther; Bezombes, Frederic; Qudeisat, Mohammad

2012-02-27

We present a novel system that can measure absolute distances of up to 300 mm with an uncertainty of the order of one micrometer, within a timeframe of 40 seconds. The proposed system uses a Michelson interferometer, a tunable laser, a wavelength meter and a computer for analysis. The principle of synthetic wave creation is used in a novel way in that the system employs an initial low precision estimate of the distance, obtained using a triangulation, or time-of-flight, laser system, or similar, and then iterates through a sequence of progressively smaller synthetic wavelengths until it reaches micrometer uncertainties in the determination of the distance. A further novel feature of the system is its use of Fourier transform phase analysis techniques to achieve sub-wavelength accuracy. This method has the major advantages of being relatively simple to realize, offering demonstrated high relative precisions better than 5 × 10(-5). Finally, the fact that this device does not require a continuous line-of-sight to the target as is the case with other configurations offers significant advantages.

A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

Science.gov (United States)

McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

2007-09-01

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium

International Nuclear Information System (INIS)

McCarron, Daniel J.; Hughes, Ifan G.; Tierney, Patrick; Cornish, Simon L.

2007-01-01

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D 2 transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude

High temperature vapors science and technology

CERN Document Server

Hastie, John

2012-01-01

High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

Copper-vapor-catalyzed chemical vapor deposition of graphene on dielectric substrates

Science.gov (United States)

Yang, Chao; Wu, Tianru; Wang, Haomin; Zhang, Xuefu; Shi, Zhiyuan; Xie, Xiaoming

2017-07-01

Direct synthesis of high-quality graphene on dielectric substrates is important for its application in electronics. In this work, we report the process of copper-vapor-catalyzed chemical vapor deposition of high-quality and large graphene domains on various dielectric substrates. The copper vapor plays a vital role on the growth of transfer-free graphene. Both single-crystal domains that are much larger than previous reports and high-coverage graphene films can be obtained by adjusting the growth duration. The quality of the obtained graphene was verified to be comparable with that of graphene grown on Cu foil. The progress reported in this work will aid the development of the application of transfer-free graphene in the future.

Full-scale testing and early production results from horizontal air sparging and soil vapor extraction wells remediating jet fuel in soil and groundwater at JFK International Airport, New York

International Nuclear Information System (INIS)

Roth, R.J.; Bianco, P.; Pressly, N.C.

1996-01-01

Jet fuel contaminated soil and groundwater contaminated at the International Arrivals Building (IAB) of the JFK International Airport in Jamaica, New York, are being remediated using soil vapor extraction (SVE) and air sparging (AS). The areal extent of the contaminated soil is estimated to be 70 acres and the volume of contaminated groundwater is estimated to be 2.3 million gallons. The remediation uses approximately 13,000 feet of horizontal SVE (HSVE) wells and 7,000 feet of horizontal AS (HAS) wells. The design of the HSVE and HAS wells was based on a pilot study followed by a full-scale test. In addition to the horizontal wells, 28 vertical AS wells and 15 vertical SVE wells are used. Three areas are being remediated, thus, three separate treatment systems have been installed. The SVE and AS wells are operated continuously while groundwater will be intermittently extracted at each HAS well, treated by liquid phase activated carbon and discharged into stormwater collection sewerage. Vapors extracted by the SVE wells are treated by vapor phase activated carbon and discharged into ambient air. The duration of the remediation is anticipated to be between two and three years before soil and groundwater are remediated to New York State cleanup criteria for the site. Based on the monitoring data for the first two months of operation, approximately 14,600 lbs. of vapor phase VOCs have been extracted. Analyses show that the majority of the VOCs are branched alkanes, branched alkenes, cyclohexane and methylated cyclohexanes

Estimated vapor pressure for WTP process streams

Energy Technology Data Exchange (ETDEWEB)

Pike, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-01-01

Design assumptions during the vacuum refill phase of the Pulsed Jet Mixers (PJMs) in the Hanford Waste Treatment and Immobilization Plant (WTP) equate the vapor pressure of all process streams to that of water when calculating the temperature at which the vacuum refill is reduced or eliminated. WTP design authority asked the authors to assess this assumption by performing calculations on proposed feed slurries to calculate the vapor pressure as a function of temperature. The vapor pressure was estimated for each WTP waste group. The vapor pressure suppression caused by dissolved solids is much greater than the increase caused by organic components such that the vapor pressure for all of the waste group compositions is less than that of pure water. The vapor pressure for each group at 145°F ranges from 81% to 98% of the vapor pressure of water. If desired, the PJM could be operated at higher temperatures for waste groups with high dissolved solids that suppress vapor pressure. The SO4 group with the highest vapor pressure suppression could be operated up to 153°F before reaching the same vapor pressure of water at 145°F. However, most groups would reach equivalent vapor pressure at 147 to 148°F. If any of these waste streams are diluted, the vapor pressure can exceed the vapor pressure of water at mass dilution ratios greater than 10, but the overall effect is less than 0.5%.

Climatic Analysis of Oceanic Water Vapor Transports Based on Satellite E-P Datasets

Science.gov (United States)

Smith, Eric A.; Sohn, Byung-Ju; Mehta, Vikram

2004-01-01

Understanding the climatically varying properties of water vapor transports from a robust observational perspective is an essential step in calibrating climate models. This is tantamount to measuring year-to-year changes of monthly- or seasonally-averaged, divergent water vapor transport distributions. This cannot be done effectively with conventional radiosonde data over ocean regions where sounding data are generally sparse. This talk describes how a methodology designed to derive atmospheric water vapor transports over the world oceans from satellite-retrieved precipitation (P) and evaporation (E) datasets circumvents the problem of inadequate sampling. Ultimately, the method is intended to take advantage of the relatively complete and consistent coverage, as well as continuity in sampling, associated with E and P datasets obtained from satellite measurements. Independent P and E retrievals from Special Sensor Microwave Imager (SSM/I) measurements, along with P retrievals from Tropical Rainfall Measuring Mission (TRMM) measurements, are used to obtain transports by solving a potential function for the divergence of water vapor transport as balanced by large scale E - P conditions.

A numerical investigation of vapor intrusion--the dynamic response of contaminant vapors to rainfall events.

Science.gov (United States)

Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

2012-10-15

The U.S. government and various agencies have published guidelines for field investigation of vapor intrusion, most of which suggest soil gas sampling as an integral part of the investigation. Contaminant soil gas data are often relatively more stable than indoor air vapor concentration measurements, but meteorological conditions might influence soil gas values. Although a few field and numerical studies have considered some temporal effects on soil gas vapor transport, a full explanation of the contaminant vapor concentration response to rainfall events is not available. This manuscript seeks to demonstrate the effects on soil vapor transport during and after different rainfall events, by applying a coupled numerical model of fluid flow and vapor transport. Both a single rainfall event and seasonal rainfall events were modeled. For the single rainfall event models, the vapor response process could be divided into three steps: namely, infiltration, water redistribution, and establishment of a water lens atop the groundwater source. In the infiltration step, rainfall intensity was found to determine the speed of the wetting front and wash-out effect on the vapor. The passage of the wetting front led to an increase of the vapor concentration in both the infiltration and water redistribution steps and this effect is noted at soil probes located 1m below the ground surface. When the mixing of groundwater with infiltrated water was not allowed, a clean water lens accumulated above the groundwater source and led to a capping effect which can reduce diffusion rates of contaminant from the source. Seasonal rainfall with short time intervals involved superposition of the individual rainfall events. This modeling results indicated that for relatively deeper soil that the infiltration wetting front could not flood, the effects were damped out in less than a month after rain; while in the long term (years), possible formation of a water lens played a larger role in determining

Seasonal variation of aliphatic amines in marine sub-micrometer particles at the Cape Verde islands

Directory of Open Access Journals (Sweden)

H. Herrmann

2009-12-01

Full Text Available Monomethylamine (MA, dimethylamine (DMA and diethylamine (DEA were detected at non-negligible concentrations in sub-micrometer particles at the Cap Verde Atmospheric Observatory (CVAO located on the island of São Vicente in Cape Verde during algal blooms in 2007. The concentrations of these amines in five stage impactor samples ranged from 0–30 pg m⁻³ for MA, 130–360 pg m⁻³ for DMA and 5–110 pg m⁻³ for DEA during the spring bloom in May 2007 and 2–520 pg m⁻³ for MA, 100–1400 pg m⁻³ for DMA and 90–760 pg m⁻³ for DEA during an unexpected winter algal bloom in December 2007. Anomalously high Saharan dust deposition and intensive ocean layer deepening were found at the Atmospheric Observatory and the associated Ocean Observatory during algal bloom periods. The highest amine concentrations in fine particles (impactor stage 2, 0.14–0.42 μm indicate that amines are likely taken up from the gas phase into the acidic sub-micrometer particles. The contribution of amines to the organic carbon (OC content ranged from 0.2–2.5% C in the winter months, indicating the importance of this class of compounds to the carbon cycle in the marine environment. Furthermore, aliphatic amines originating from marine biological sources likely contribute significantly to the nitrogen content in the marine atmosphere. The average contribution of the amines to the detected nitrogen species in sub-micrometer particles can be non-negligible, especially in the winter months (0.1% N–1.5% N in the sum of nitrate, ammonium and amines. This indicates that these smaller aliphatic amines can be important for the carbon and the nitrogen cycles in the remote marine environment.

Attenuation on an Earth-space path measured in the wavelength range of 8 to 14 micrometers.

Science.gov (United States)

Wilson, R W

1970-06-19

A telescope operating over the wavelength range of 8 to 14 micrometers has been added to the Crawford Hill sun tracker for the purpose of measuring attenuation in that atmospheric window. Over a 9-month period the attenuation (typically from clouds) exceeded 10, 20, and 30 decibels for 48, 43, and 34 percent of the time.

Study of film boiling collapse behavior during vapor explosion

International Nuclear Information System (INIS)

Yagi, Masahiro; Yamano, Norihiro; Sugimoto, Jun; Abe, Yutaka; Adachi, Hiromichi; Kobayashi, Tomoyoshi.

1996-06-01

Possible large scale vapor explosions are safety concern in nuclear power plants during severe accident. In order to identify the occurrence of the vapor explosion and to estimate the magnitude of the induced pressure pulse, it is necessary to investigate the triggering condition for the vapor explosion. As a first step of this study, scooping analysis was conducted with a simulation code based on thermal detonation model. It was found that the pressure at the collapse of film boiling much affects the trigger condition of vapor explosion. Based on this analytical results, basic experiments were conducted to clarify the collapse conditions of film boiling on a high temperature solid ball surface. Film boiling condition was established by flooding water onto a high temperature stainless steel ball heated by a high frequency induction heater. After the film boiling was established, the pressure pulse generated by a shock tube was applied to collapse the steam film on the ball surface. As the experimental boundary conditions, materials and size of the balls, magnitude of pressure pulse and initial temperature of the carbon and stainless steel balls were varied. The transients of pressure and surface temperature were measured. It was found that the surface temperature on the balls sharply decreased when the pressure wave passed through the film on balls. Based on the surface temperature behavior, the film boiling collapse pattern was found to be categorized into several types. Especially, the pattern for stainless steel ball was categorized into three types; no collapse, collapse and reestablishment after collapse. It was thus clarified that the film boiling collapse behavior was identified by initial conditions and that the pressure required to collapse film boiling strongly depended on the initial surface temperature. The present results will provide a useful information for the analysis of vapor explosions based on the thermal detonation model. (J.P.N.)

Micro-Scale Thermoacoustics

Science.gov (United States)

Offner, Avshalom; Ramon, Guy Z.

2016-11-01

Thermoacoustic phenomena - conversion of heat to acoustic oscillations - may be harnessed for construction of reliable, practically maintenance-free engines and heat pumps. Specifically, miniaturization of thermoacoustic devices holds great promise for cooling of micro-electronic components. However, as devices size is pushed down to micro-meter scale it is expected that non-negligible slip effects will exist at the solid-fluid interface. Accordingly, new theoretical models for thermoacoustic engines and heat pumps were derived, accounting for a slip boundary condition. These models are essential for the design process of micro-scale thermoacoustic devices that will operate under ultrasonic frequencies. Stability curves for engines - representing the onset of self-sustained oscillations - were calculated with both no-slip and slip boundary conditions, revealing improvement in the performance of engines with slip at the resonance frequency range applicable for micro-scale devices. Maximum achievable temperature differences curves for thermoacoustic heat pumps were calculated, revealing the negative effect of slip on the ability to pump heat up a temperature gradient. The authors acknowledge the support from the Nancy and Stephen Grand Technion Energy Program (GTEP).

Vapor Pressure Data Analysis and Statistics

Science.gov (United States)

2016-12-01

near 8, 2000, and 200, respectively. The A (or a) value is directly related to vapor pressure and will be greater for high vapor pressure materials...1, (10) where n is the number of data points, Yi is the natural logarithm of the i th experimental vapor pressure value, and Xi is the...VAPOR PRESSURE DATA ANALYSIS AND STATISTICS ECBC-TR-1422 Ann Brozena RESEARCH AND TECHNOLOGY DIRECTORATE

The Effects of Scales on Autorotation of Monarch Butterfly Forewings

Science.gov (United States)

Dechello, Nicole; Lang, Amy

2014-11-01

The wings of Monarch butterflies (Danus plexippus) have scales of approximately 100 micrometers that cover their wings in a roof-shingle pattern, and these scales are hypothesized to help improve flight efficiency for their long migration. The aerodynamic effects of the scales, particularly involving the leading edge vortex formation and resulting lift, were investigated by observing the natural autorotation of forewing specimen when dropped in quiescent air. A high-speed camera recorded drop tests of 32 forewings both with scales and after removal of the scales. It was found that the scales, on average, comprised 17% of the forewing mass. Tracking software was used to analyze the videos for several parameters, including descent speed and radius of rotation. NSF ECE Grant #1358991 supported the first author as an research experience for undergraduate (REU) student.

A Simple Experiment for Determining Vapor Pressure and Enthalpy of Vaporization of Water.

Science.gov (United States)

Levinson, Gerald S.

1982-01-01

Laboratory procedures, calculations, and sample results are described for a freshman chemistry experiment in which the Clausius-Clapeyron equation is introduced as a means of describing the variation of vapor pressure with temperature and for determining enthalpy of vaporization. (Author/SK)

MoXy fiber with active cooling cap for bovine prostate vaporization with high power 200W 532 nm laser

Science.gov (United States)

Peng, Steven Y.; Kang, Hyun Wook; Pirzadeh, Homa; Stinson, Douglas

2011-03-01

A novel MoXyTM fiber delivery device with Active Cooling Cap (ACCTM) is designed to transmit up to 180W of 532 nm laser light to treat benign prostatic hyperplasia (BPH). Under such high power tissue ablation, effective cooling is key to maintaining fiber power transmission and ensuring the reliability of the fiber delivery device To handle high power and reduce fiber degradation, the MoXy fiber features a larger core size (750 micrometer) and an internal fluid channel to ensure better cooling of the fiber tip to prevent the cap from burning, detaching, or shattering during the BPH treatment. The internal cooling channel was created with a metal cap and tubing that surrounds the optical fiber. In this study MoXy fibers were used to investigate the effect of power levels of 120 and 200 W on in-vitro bovine prostate ablation using a 532 nm XPSTM laser system. For procedures requiring more than 100 kJ, the MoXy fiber at 200W removed tissue at twice the rate of the current HPS fiber at 120W. The fiber maintained a constant tissue vaporization rate during the entire tissue ablation process. The coagulation at 200W was about 20% thicker than at 120W. In conclusion, the new fibers at 200W doubled the tissue removal rate, maintained vaporization efficiency throughout delivery of 400kJ energy, and induced similar coagulation to the existing HPS fiber at 120W.

Improvements to vapor generators

International Nuclear Information System (INIS)

Keller, Arthur; Monroe, Neil.

1976-01-01

A supporting system is proposed for vapor generators of the 'supported' type. Said supporting system is intended to compensate the disparities of thermal expansion due to the differences in the vertical dimensions of the tubes in the walls of the combustion chamber and their collectors compared to that of the balloon tanks and the connecting tube clusters of vaporization, the first one being longer than the second ones. Said system makes it possible to build said combustion chamber higher than the balloon tanks and the tube clusters of vaporization. The capacity of steam production is thus enhanced [fr

Thermogravimetric measurements of liquid vapor pressure

International Nuclear Information System (INIS)

Rong Yunhong; Gregson, Christopher M.; Parker, Alan

2012-01-01

Highlights: ► Rapid determination of vapor pressure by TGA. ► Demonstration of limitations of currently available approaches in literature. ► New model for vapor pressure assessment of small size samples in TGA. ► New model accounts for vapor diffusion and sample geometry and measures vapor pressure normally within 10%. - Abstract: A method was developed using thermo-gravimetric analysis (TGA) to determine the vapor pressure of volatile liquids. This is achieved by measuring the rate of evaporation (mass loss) of a pure liquid contained within a cylindrical pan. The influence of factors like sample geometry and vapor diffusion on evaporation rate are discussed. The measurement can be performed across a wide range of temperature yielding reasonable results up to 10 kPa. This approach may be useful as a rapid and automatable method for measuring the volatility of flavor and fragrance raw materials.

Petroleum Vapor - Field Technical

Science.gov (United States)

The screening approach being developed by EPA OUST to evaluate petroleum vapor intrusion (PVI) requires information that has not be routinely collected in the past at vapor intrusion sites. What is the best way to collect this data? What are the relevant data quality issues and ...

A Numerical Investigation of Vapor Intrusion — the Dynamic Response of Contaminant Vapors to Rainfall Events

Science.gov (United States)

Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

2013-01-01

The U.S. government and various agencies have published guidelines for field investigation of vapor intrusion, most of which suggest soil gas sampling as an integral part of the investigation. Contaminant soil gas data are often relatively more stable than indoor air vapor concentration measurements, but meteorological conditions might influence soil gas values. Although a few field and numerical studies have considered some temporal effects on soil gas vapor transport, a full explanation of the contaminant vapor concentration response to rainfall events is not available. This manuscript seeks to demonstrate the effects on soil vapor transport during and after different rainfall events, by applying a coupled numerical model of fluid flow and vapor transport. Both a single rainfall event and seasonal rainfall events were modeled. For the single rainfall event models, the vapor response process could be divided into three steps: namely, infiltration, water redistribution, and establishment of a water lens atop the groundwater source. In the infiltration step, rainfall intensity was found to determine the speed of the wetting front and wash-out effect on the vapor. The passage of the wetting front led to an increase of the vapor concentration in both the infiltration and water redistribution steps and this effect is noted at soil probes located 1 m below the ground surface. When the mixing of groundwater with infiltrated water was not allowed, a clean water lens accumulated above the groundwater source and led to a capping effect which can reduce diffusion rates of contaminant from the source. Seasonal rainfall with short time intervals involved superposition of the individual rainfall events. This modeling results indicated that for relatively deeper soil that the infiltration wetting front could not flood, the effects were damped out in less than a month after rain; while in the long term (years), possible formation of a water lens played a larger role in

Rare-Earth Oxide Ion (Tm3+, Ho3+, and U3+) Doped Glasses and Fibres for 1.8 to 4 Micrometer Coherent and Broadband Sources

Science.gov (United States)

2006-07-24

oxide ( TeO2 ) , fluorine- containing silicate (SiOF2) and germanate (GeOF2) glass hosts for each dopant by characterising the spectroscopic properties...Earth Oxide Ion (Tm3+, Ho3+, And U3+) Doped Glasses And Fibres For 1.8 To 4 Micrometer Coherent And Broadband Sources 5c. PROGRAM ELEMENT NUMBER 5d...Rare-earth oxide ion (Tm3+, Ho3+, and U3+) doped glasses and fibres for 1.8 to 4 micrometer coherent and broadband sources Report prepared

An Accurate Method for Computing the Absorption of Solar Radiation by Water Vapor

Science.gov (United States)

Chou, M. D.

1980-01-01

The method is based upon molecular line parameters and makes use of a far wing scaling approximation and k distribution approach previously applied to the computation of the infrared cooling rate due to water vapor. Taking into account the wave number dependence of the incident solar flux, the solar heating rate is computed for the entire water vapor spectrum and for individual absorption bands. The accuracy of the method is tested against line by line calculations. The method introduces a maximum error of 0.06 C/day. The method has the additional advantage over previous methods in that it can be applied to any portion of the spectral region containing the water vapor bands. The integrated absorptances and line intensities computed from the molecular line parameters were compared with laboratory measurements. The comparison reveals that, among the three different sources, absorptance is the largest for the laboratory measurements.

Gas analysis during the chemical vapor deposition of carbon

International Nuclear Information System (INIS)

Lieberman, M.L.; Noles, G.T.

1973-01-01

Gas chromatographic analyses were performed during the chemical vapor deposition of carbon in both isothermal and thermal gradient systems. Such data offer insight into the gas phase processes which occur during deposition and the interrelations which exist between gas composition, deposition rate, and resultant structure of the deposit. The results support a carbon CVD model presented previously. The application of chromatographic analysis to research, development, and full-scale facilities is shown. (U.S.)

The lithium vapor box divertor

International Nuclear Information System (INIS)

Goldston, R J; Schwartz, J; Myers, R

2016-01-01

It has long been recognized that volumetric dissipation of the plasma heat flux from a fusion power system is preferable to its localized impingement on a material surface. Volumetric dissipation mitigates both the anticipated very high heat flux and intense particle-induced damage due to sputtering. Recent projections to a tokamak demonstration power plant suggest an immense upstream parallel heat flux, of order 20 GW m −2 , implying that fully detached operation may be a requirement for the success of fusion power. Building on pioneering work on the use of lithium by Nagayama et al and by Ono et al as well as earlier work on the gas box divertor by Watkins and Rebut, we present here a concept for a lithium vapor box divertor, in which lithium vapor extracts momentum and energy from a fusion-power-plant divertor plasma, using fully volumetric processes. At the high powers and pressures that are projected this requires a high density of lithium vapor, which must be isolated from the main plasma in order to avoid lithium build-up on the chamber walls or in the plasma. Isolation is achieved through a powerful multi-box differential pumping scheme available only for condensable vapors. The preliminary box-wise calculations are encouraging, but much more work is required to demonstrate the practical viability of this scheme, taking into account at least 2D plasma and vapor flows within and between the vapor boxes and out of the vapor boxes to the main plasma. (paper)

Vapor pressures and enthalpies of vaporization of a series of the linear aliphatic aldehydes

Czech Academy of Sciences Publication Activity Database

Verevkin, S. P.; Krasnykh, E. L.; Vasiltsova, T. V.; Koutek, Bohumír; Doubský, Jan; Heintz, A.

2003-01-01

Roč. 206, - (2003), s. 331-339 ISSN 0378-3812 Institutional research plan: CEZ:AV0Z4055905 Keywords : aldehydes * vapor pressure * enthalpy of vaporization Subject RIV: CC - Organic Chemistry Impact factor: 1.165, year: 2003

Vapor pressures and enthalpies of vaporization of a series of γ and δ-lactones by correlation gas chromatography

International Nuclear Information System (INIS)

Kozlovskiy, Mikhail; Gobble, Chase; Chickos, James

2014-01-01

Highlights: • The vaporization enthalpies of γ-octanolactone, γ- and δ-undecanolactone and γ and δ-dodecanolactone are reported. • Equations for predicting the vapor pressures over the temperature range T = (298.15 to 350) K are provided. • Vaporization enthalpies are compared to predicted values. - Abstract: The vaporization enthalpies of γ-octanolactone, γ- and δ-undecanolactone and γ and δ-dodecanolactone used commercially as flavor ingredients are reported as are their vapor pressures over the temperature range T = (298.15 to 350) K. Vaporization enthalpies at T = 298.15 K of: (66.0 ± 3.9), (79.4 ± 4.4), (80.1 ± 4.5), (83.9 ± 4.6), and (84.61 ± 4.7) kJ · mol −1 and vapor pressures also at T = 298.15 K of: (2.8 ± 0.9), (0.12 ± 0.05), (0.09 ± 0.04), (0.04 ± 0.02), and (0.03 ± 0.02) Pa, respectively, have been evaluated by correlation gas chromatography experiments. The vaporization enthalpies of the lactones studied are reproduced within ±0.5 kJ · mol −1 using a group additivity scheme reported previously for γ- and δ-lactones. The vaporization enthalpies of the γ- and δ-lactones are compared to a similar series of ω-lactones

Air blast effects on nuclear power plants from vapor cloud explosions

International Nuclear Information System (INIS)

Wiedermann, A.H.; Eichler, T.V.; Kot, C.A.

1981-01-01

To assess the hazards arising from the explosion of a large flammable vapor cloud a method was developed for estimating the air blast field assuming a detonation wave is established. The actual 'pancake' like geometry typical for negatively buoyant vapor clouds is taken into account. The cloud height and other characteristics are generated by a global cloud dynamics model for negatively buoyant clouds. This model provides the cloud height as a function of fuel vapor concentration and other pertinent variables. A two-dimensional Eulerian shock hydrodynamic computer code is utilized to compute the blast environment in the neighborhood of the end of the cloud. The initial field is taken to be a quasi-steady explosion field calculated by the method of characteristics for a thin Prandtl-Meyer expansion wave, and the upward driven air shock representing the combustion and pressure relief processes inherent in the pancake geometry. This initial fields is established in the 2-D hydrocode at a time corresponding to the arrival of the detonation front at the cloud edge. It is to be noted that the local blast environment scales with respect to the cloud height. The computational results indicate that it is essential to include the influence of cloud geometry for the realistic prediction of the air blast hazard arising from the explosion of a negatively buoyant vapor cloud. (orig./HP)

On the use of GPS tomography to investigate water vapor variability during a Mistral/sea breeze event in southeastern France

Science.gov (United States)

Bastin, Sophie; Champollion, Cédric; Bock, Olivier; Drobinski, Philippe; Masson, Frédéric

2005-03-01

Global Positioning System (GPS) tomography analyses of water vapor, complemented by high-resolution numerical simulations are used to investigate a Mistral/sea breeze event in the region of Marseille, France, during the ESCOMPTE experiment. This is the first time GPS tomography has been used to validate the three-dimensional water vapor concentration from numerical simulation, and to analyze a small-scale meteorological event. The high spatial and temporal resolution of GPS analyses provides a unique insight into the evolution of the vertical and horizontal distribution of water vapor during the Mistral/sea-breeze transition.

Vapor and healing treatment for CH3NH3PbI3-xClx films toward large-area perovskite solar cells

Science.gov (United States)

Gouda, Laxman; Gottesman, Ronen; Tirosh, Shay; Haltzi, Eynav; Hu, Jiangang; Ginsburg, Adam; Keller, David A.; Bouhadana, Yaniv; Zaban, Arie

2016-03-01

Hybrid methyl-ammonium lead trihalide perovskites are promising low-cost materials for use in solar cells and other optoelectronic applications. With a certified photovoltaic conversion efficiency record of 20.1%, scale-up for commercial purposes is already underway. However, preparation of large-area perovskite films remains a challenge, and films of perovskites on large electrodes suffer from non-uniform performance. Thus, production and characterization of the lateral uniformity of large-area films is a crucial step towards scale-up of devices. In this paper, we present a reproducible method for improving the lateral uniformity and performance of large-area perovskite solar cells (32 cm2). The method is based on methyl-ammonium iodide (MAI) vapor treatment as a new step in the sequential deposition of perovskite films. Following the MAI vapor treatment, we used high throughput techniques to map the photovoltaic performance throughout the large-area device. The lateral uniformity and performance of all photovoltaic parameters (Voc, Jsc, Fill Factor, Photo-conversion efficiency) increased, with an overall improved photo-conversion efficiency of ~100% following a vapor treatment at 140 °C. Based on XRD and photoluminescence measurements, We propose that the MAI treatment promotes a ``healing effect'' to the perovskite film which increases the lateral uniformity across the large-area solar cell. Thus, the straightforward MAI vapor treatment is highly beneficial for large scale commercialization of perovskite solar cells, regardless of the specific deposition method.Hybrid methyl-ammonium lead trihalide perovskites are promising low-cost materials for use in solar cells and other optoelectronic applications. With a certified photovoltaic conversion efficiency record of 20.1%, scale-up for commercial purposes is already underway. However, preparation of large-area perovskite films remains a challenge, and films of perovskites on large electrodes suffer from non

A study on vapor explosions

International Nuclear Information System (INIS)

Takagi, N.; Shoji, M.

1979-01-01

An experimental study was carried out for vapor explosions of molten tin falling in water. For various initial metal temperatures and subcooling of water, transient pressure of the explosions, relative frequency of the explosions and the position where the explosions occur were measured in detail. The influence of ambient pressure was also investigated. From the results, it was concluded that the vapor explosion is closely related to the collapse of a vapor film around the molten metal. (author)

Physical model for vaporization

OpenAIRE

Garai, Jozsef

2006-01-01

Based on two assumptions, the surface layer is flexible, and the internal energy of the latent heat of vaporization is completely utilized by the atoms for overcoming on the surface resistance of the liquid, the enthalpy of vaporization was calculated for 45 elements. The theoretical values were tested against experiments with positive result.

Propelling a water drop with the vapor-mediated Marangoni effect

Science.gov (United States)

Kim, Seungho; Kim, Ho-Young

2013-11-01

We show that a water drop on solid surfaces can be propelled just by placing a volatile alcohol drop nearby. It is found to be because the water-air interface near the alcohol drop mixes with alcohol vapor, thereby locally lowering the surface tension. The surface-tension-gradient induces the motion of the water drop, enabling the trajectory control of water drops through the motion of remote alcohol drops. This vapor-mediated Marangoni effect also gives rise to other interesting interfacial flow phenomena, such as nucleation of holes on a water film and ballooning of a water drop hanging from a syringe needle with the approach of an alcohol drop. We visualize such interfacial dynamics with a high-speed camera and rationalize their salient features by scaling analysis. This work was supported by the National Research Foundation of Korea (grant no. 2012-008023).

Quality and Control of Water Vapor Winds

Science.gov (United States)

Jedlovec, Gary J.; Atkinson, Robert J.

1996-01-01

Water vapor imagery from the geostationary satellites such as GOES, Meteosat, and GMS provides synoptic views of dynamical events on a continual basis. Because the imagery represents a non-linear combination of mid- and upper-tropospheric thermodynamic parameters (three-dimensional variations in temperature and humidity), video loops of these image products provide enlightening views of regional flow fields, the movement of tropical and extratropical storm systems, the transfer of moisture between hemispheres and from the tropics to the mid- latitudes, and the dominance of high pressure systems over particular regions of the Earth. Despite the obvious larger scale features, the water vapor imagery contains significant image variability down to the single 8 km GOES pixel. These features can be quantitatively identified and tracked from one time to the next using various image processing techniques. Merrill et al. (1991), Hayden and Schmidt (1992), and Laurent (1993) have documented the operational procedures and capabilities of NOAA and ESOC to produce cloud and water vapor winds. These techniques employ standard correlation and template matching approaches to wind tracking and use qualitative and quantitative procedures to eliminate bad wind vectors from the wind data set. Techniques have also been developed to improve the quality of the operational winds though robust editing procedures (Hayden and Veldon 1991). These quality and control approaches have limitations, are often subjective, and constrain wind variability to be consistent with model derived wind fields. This paper describes research focused on the refinement of objective quality and control parameters for water vapor wind vector data sets. New quality and control measures are developed and employed to provide a more robust wind data set for climate analysis, data assimilation studies, as well as operational weather forecasting. The parameters are applicable to cloud-tracked winds as well with minor

International Space Science Institute Workshop on Shallow Clouds, Water Vapor, Circulation and Climate Sensitivity

CERN Document Server

Winker, David; Bony, Sandrine; Stevens, Bjorn

2018-01-01

This volume presents a series of overview articles arising from a workshop exploring the links among shallow clouds, water vapor, circulation, and climate sensitivity. It provides a state-of-the art synthesis of understanding about the coupling of clouds and water vapor to the large-scale circulation. The emphasis is on two phenomena, namely the self-aggregation of deep convection and interactions between low clouds and the large-scale environment, with direct links to the sensitivity of climate to radiative perturbations. Each subject is approached using simulations, observations, and synthesizing theory; particular attention is paid to opportunities offered by new remote-sensing technologies, some still prospective. The collection provides a thorough grounding in topics representing one of the World Climate Research Program’s Grand Challenges. Previously published in Surveys in Geophysics, Volume 38, Issue 6, 2017 The articles “Observing Convective Aggregation”, “An Observational View of Relationshi...

Structural Color Model Based on Surface Morphology of MORPHO Butterfly Wing Scale

Science.gov (United States)

Huang, Zhongjia; Cai, Congcong; Wang, Gang; Zhang, Hui; Huttula, Marko; Cao, Wei

2016-05-01

Color production through structural coloration is created by micrometer and sub-micrometer surface textures which interfere with visible light. The shiny blue of morpho menelaus is a typical example of structural coloring. Modified from morphology of the morpho scale, a structure of regular windows with two side offsets was constructed on glass substrates. Optical properties of the bioinspired structure were studied through numerical simulations of light scattering. Results show that the structure can generate monochromatic light scattering. Wavelength of scattered light is tunable via changing the spacing between window shelves. Compared to original butterfly model, the modified one possesses larger illumination scopes in azimuthal distributions despite being less in polar directions. Present bionic structure is periodically repeated and is easy to fabricate. It is hoped that the computational materials design work can inspire future experimental realizations of such a structure in photonics applications.

Vaporization of irradiated droplets

International Nuclear Information System (INIS)

Armstrong, R.L.; O'Rourke, P.J.; Zardecki, A.

1986-01-01

The vaporization of a spherically symmetric liquid droplet subject to a high-intensity laser flux is investigated on the basis of a hydrodynamic description of the system composed of the vapor and ambient gas. In the limit of the convective vaporization, the boundary conditions at the fluid--gas interface are formulated by using the notion of a Knudsen layer in which translational equilibrium is established. This leads to approximate jump conditions at the interface. For homogeneous energy deposition, the hydrodynamic equations are solved numerically with the aid of the CON1D computer code (''CON1D: A computer program for calculating spherically symmetric droplet combustion,'' Los Alamos National Laboratory Report No. LA-10269-MS, December, 1984), based on the implict continuous--fluid Eulerian (ICE) [J. Comput. Phys. 8, 197 (1971)] and arbitrary Lagrangian--Eulerian (ALE) [J. Comput. Phys. 14, 1227 (1974)] numerical mehtods. The solutions exhibit the existence of two shock waves propagating in opposite directions with respect to the contact discontinuity surface that separates the ambient gas and vapor

Micromanipulation and pick-up system for X-Ray diffraction characterization of micrometer-sized single particles

International Nuclear Information System (INIS)

Takeichi, Y; Inami, N; Saito, K; Otori, H; Sagayama, R; Kumai, R; Ono, K; Ueno, T

2014-01-01

We describe a micromanipulation and pick-up system for preparing a micrometer-sized single particle for X-ray diffraction characterization. Combining a microgripper based on microelectromechanical systems, piezo-motor-driven linear stages, and a gamepad, the system provides precise and intuitive handling of the object. Single-crystal X-ray diffraction measurements of Sm-Fe-N permanent magnet were performed using this system. We also describe a method to distinguish crystallographically homogeneous particles found in powder-form samples.

Large-scale fabrication of linear low density polyethylene/layered double hydroxides composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties

Energy Technology Data Exchange (ETDEWEB)

Xie, Jiazhuo; Zhang, Kun; Zhao, Qinghua [College of Chemistry and Material Science, Shandong Agricultural University, 61 Daizong Street, Tai' an 271018 (China); Wang, Qingguo, E-mail: wqgyyy@126.com [College of Food Science and Engineering, Shandong Agricultural University, 61 Daizong Street, Tai' an 271018 (China); Xu, Jing, E-mail: jiaxu@sdau.edu.cn [College of Chemistry and Material Science, Shandong Agricultural University, 61 Daizong Street, Tai' an 271018 (China)

2016-11-15

Novel LDH intercalated with organic aliphatic long-chain anion was large-scale synthesized innovatively by high-energy ball milling in one pot. The linear low density polyethylene (LLDPE)/layered double hydroxides (LDH) composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties were fabricated by melt blending and blowing process. FT IR, XRD, SEM results show that LDH particles were dispersed uniformly in the LLDPE composite films. Particularly, LLDPE composite film with 1% LDH exhibited the optimal performance among all the composite films with a 60.36% enhancement in the water vapor barrier property and a 45.73 °C increase in the temperature of maximum mass loss rate compared with pure LLDPE film. Furthermore, the improved infrared absorbance (1180–914 cm{sup −1}) of LLDPE/LDH films revealed the significant enhancement of heat retention. Therefore, this study prompts the application of LLDPE/LDH films as agricultural films with superior heat retention. - Graphical abstract: The fabrication process of LLDPE/LDH composite films. - Highlights: • LDH with basal spacing of 4.07 nm was synthesized by high-energy ball milling. • LLDPE composite films with homogeneous LDH dispersion were fabricated. • The properties of LLDPE/LDH composite films were improved. • LLDPE/LDH composite films show superior heat retention property.

Large-scale fabrication of linear low density polyethylene/layered double hydroxides composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties

International Nuclear Information System (INIS)

Xie, Jiazhuo; Zhang, Kun; Zhao, Qinghua; Wang, Qingguo; Xu, Jing

2016-01-01

Novel LDH intercalated with organic aliphatic long-chain anion was large-scale synthesized innovatively by high-energy ball milling in one pot. The linear low density polyethylene (LLDPE)/layered double hydroxides (LDH) composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties were fabricated by melt blending and blowing process. FT IR, XRD, SEM results show that LDH particles were dispersed uniformly in the LLDPE composite films. Particularly, LLDPE composite film with 1% LDH exhibited the optimal performance among all the composite films with a 60.36% enhancement in the water vapor barrier property and a 45.73 °C increase in the temperature of maximum mass loss rate compared with pure LLDPE film. Furthermore, the improved infrared absorbance (1180–914 cm −1 ) of LLDPE/LDH films revealed the significant enhancement of heat retention. Therefore, this study prompts the application of LLDPE/LDH films as agricultural films with superior heat retention. - Graphical abstract: The fabrication process of LLDPE/LDH composite films. - Highlights: • LDH with basal spacing of 4.07 nm was synthesized by high-energy ball milling. • LLDPE composite films with homogeneous LDH dispersion were fabricated. • The properties of LLDPE/LDH composite films were improved. • LLDPE/LDH composite films show superior heat retention property.

Coupling thermal atomic vapor to an integrated ring resonator

International Nuclear Information System (INIS)

Ritter, R; Kübler, H; Pfau, T; Löw, R; Gruhler, N; Pernice, W H P

2016-01-01

Strongly interacting atom–cavity systems within a network with many nodes constitute a possible realization for a quantum internet which allows for quantum communication and computation on the same platform. To implement such large-scale quantum networks, nanophotonic resonators are promising candidates because they can be scalably fabricated and interconnected with waveguides and optical fibers. By integrating arrays of ring resonators into a vapor cell we show that thermal rubidium atoms above room temperature can be coupled to photonic cavities as building blocks for chip-scale hybrid circuits. Although strong coupling is not yet achieved in this first realization, our approach provides a key step towards miniaturization and scalability of atom–cavity systems. (paper)

A Citizen's Guide to Vapor Intrusion Mitigation

Science.gov (United States)

This guide describes how vapor intrusion is the movement of chemical vapors from contaminated soil and groundwater into nearby buildings.Vapors primarily enter through openings in the building foundation or basement walls.

Condensation of vapor bubble in subcooled pool

Science.gov (United States)

Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.

2017-02-01

We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

Method for Hot Real-Time Sampling of Pyrolysis Vapors

Energy Technology Data Exchange (ETDEWEB)

Pomeroy, Marc D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-09-29

Biomass Pyrolysis has been an increasing topic of research, in particular as a replacement for crude oil. This process utilizes moderate temperatures to thermally deconstruct the biomass which is then condensed into a mixture of liquid oxygenates to be used as fuel precursors. Pyrolysis oils contain more than 400 compounds, up to 60 percent of which do not re-volatilize for subsequent chemical analysis. Vapor chemical composition is also complicated as additional condensation reactions occur during the condensation and collection of the product. Due to the complexity of the pyrolysis oil, and a desire to catalytically upgrade the vapor composition before condensation, online real-time analytical techniques such as Molecular Beam Mass Spectrometry (MBMS) are of great use. However, in order to properly sample hot pyrolysis vapors, many challenges must be overcome. Sampling must occur within a narrow range of temperatures to reduce product composition changes from overheating or partial condensation or plugging of lines from condensed products. Residence times must be kept at a minimum to reduce further reaction chemistries. Pyrolysis vapors also form aerosols that are carried far downstream and can pass through filters resulting in build-up in downstream locations. The co-produced bio-char and ash from the pyrolysis process can lead to plugging of the sample lines, and must be filtered out at temperature, even with the use of cyclonic separators. A practical approach for considerations and sampling system design, as well as lessons learned are integrated into the hot analytical sampling system of the National Renewable Energy Laboratory's (NREL) Thermochemical Process Development Unit (TCPDU) to provide industrially relevant demonstrations of thermochemical transformations of biomass feedstocks at the pilot scale.

Kinetics of excited levels in copper-vapor laser

International Nuclear Information System (INIS)

Smilanski, I.

1981-10-01

A full and representative description of the excited copper level kinetics in a copper-vapor laser is presented. The research was carried out in three stages. The first stage was the development of a representative and reliable measurement cell. A laser tube constructed of refractory materials and an excitation circuit which provides short pulses at a high repetition rate to heat the tube and excite the copper atoms were developed. This stage was also dedicated to characterizing the laser and studying its scaling laws. In the second stage a rapid neasuring system which avoids the problem of spectral line shape was developed. The system is based on the 'hook' method, which utilizes the anomalous dispersion in the vicinity of an atomic line. The light source, a wide band nitrogen-laser-pumped dye laser, ensures a short sampling time, and the recording system, with a television camera face as the recording medium, allows precise data reduction. In the third stage the excited copper level kinetics in a copper vapor laser is measured. The principal conclusions, that only a small part of the energy in the discharge is utilized to populate the upper laser levels and that the lower laser level population is very large at the end of the excitation pulse and cannot be attributed to relaxation of the upper levels, necessitate a new kinetic description of the copper-vapor laser. The laser is not self-terminating; it is activated and terminated by the electrical discharge

Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

Energy Technology Data Exchange (ETDEWEB)

Freud, Roy [Nuclear Research Center - Negev, Beer-Sheva (Israel)], E-mail: freud@bgu.ac.il; Harari, Ronen [Nuclear Research Center - Negev, Beer-Sheva (Israel); Sher, Eran [Pearlstone Center for Aeronautical Studies, Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva (Israel)

2009-04-15

Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux

Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

International Nuclear Information System (INIS)

Freud, Roy; Harari, Ronen; Sher, Eran

2009-01-01

Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux during the cooling

Vaporization studies of plasma interactive materials in simulated plasma disruption events

International Nuclear Information System (INIS)

Stone, C.A. IV; Croessmann, C.D.; Whitley, J.B.

1988-03-01

The melting and vaporization that occur when plasma facing materials are subjected to a plasma disruption will severely limit component lifetime and plasma performance. A series of high heat flux experiments was performed on a group of fusion reactor candidate materials to model material erosion which occurs during plasma disruption events. The Electron Beam Test System was used to simulate single disruption and multiple disruption phenomena. Samples of aluminum, nickel, copper, molybdenum, and 304 stainless steel were subjected to a variety of heat loads, ranging from 100 to 400 msec pulses of 8 to 18 kWcm 2 . It was found that the initial surface temperature of a material strongly influences the vaporization process and that multiple disruptions do not scale linearly with respect to single disruption events. 2 refs., 9 figs., 5 tabs

New target for high-intensity laser-matter interaction: Gravitational flow of micrometer-sized powders

International Nuclear Information System (INIS)

Servol, M.; Quere, F.; Bougeard, M.; Monot, P.; Martin, Ph.; Faenov, A.Ya; Pikuz, T.A.; Audebert, P.; Francucci, M.; Petrocelli, G.

2005-01-01

The design of efficient targets for high-intensity laser-matter interaction is essential to fully exploit the advantages of laser-induced photons or particles sources. We present an advantageous kind of target, consisting in a free gravitational flow of micrometer-sized powder, and describe its main technical characteristics. We demonstrate a laser-induced keV x-ray source using this target, and show that the photon flux obtained for the Kα line of Si by irradiating different silica powders is comparable to the one obtained with a bulk silica target

Vapor deposition of tantalum and tantalum compounds

International Nuclear Information System (INIS)

Trkula, M.

1996-01-01

Tantalum, and many of its compounds, can be deposited as coatings with techniques ranging from pure, thermal chemical vapor deposition to pure physical vapor deposition. This review concentrates on chemical vapor deposition techniques. The paper takes a historical approach. The authors review classical, metal halide-based techniques and current techniques for tantalum chemical vapor deposition. The advantages and limitations of the techniques will be compared. The need for new lower temperature processes and hence new precursor chemicals will be examined and explained. In the last section, they add some speculation as to possible new, low-temperature precursors for tantalum chemical vapor deposition

Surface-immobilized hydrogel patterns on length scales from micrometer to nanometer

Science.gov (United States)

Zeira, Assaf

The present work concentrates on the study of pattern generation and transfer processes of monolayer covered surfaces, deriving from the basic working concept of Constructive Lithography. As an advancement of constructive lithography, we developed a direct, one-step printing (contact electrochemical printing, CEP) and replication (contact electrochemical replication, CER) of hydrophilic organic monolayer patterns surrounded by a hydrophobic monolayer background. In addition, we present a process of transfer of metal between two contacting solid surfaces to predefined monolayer template pattern sites (contact electrochemical transfer, CET). This thesis shows that CEP, CER, and CET may be implemented under a variety of different experimental conditions, regardless of whether the initial "master" pattern was created by a parallel (fast) or serial (slow) patterning process. CEP and CER also posses the unique attractive property that each replica may equally function as master stamp in the fabrication of additional replicas. Moreover, due to a mechanism of selfcorrection patterned surfaces produced these process are often free of defects that the initial "master" stamp may had. We finally show that the electrochemical patterning of OTS monolayers on silicon can be further extended to flexible polymeric substrate materials as well as to a variety of chemical manipulations, allowing the fabrication of tridimensional (3D) composite structures made on the basis of readily available OTS compound. The results obtained suggest that such contact electrochemical processes could be used to rapidly generate multiple copies of surface patterns spanning variable length scales, this basic approach being applicable to rigid as well as flexible substrate materials.

Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex

Science.gov (United States)

The role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampl...

Effect of growth conditions on the biodegradation kinetics of toluene by P. putida 54G in a vapor phase bioreactor

International Nuclear Information System (INIS)

Mirpuri, R.; Jones, W.; Krieger, E.; McFeters, G.

1994-01-01

Biodegradation of volatile organic compounds such as petroleum hydrocarbons and xenobiotic agents in the vapor phase is a promising new concept in well-head and end-of-pipe treatment which may have wide application where in-situ approaches are not feasible. The microbial degradation of the volatile organics can be carried out in vapor phase bioreactors which contain inert packing materials. Scale-up of these reactors from a bench scale to a pilot plant can best be achieved by the use of a predictive model, the success of which depends on accurate estimates of parameters defined in the model such as biodegradation kinetic and stoichiometric coefficients. The phenomena of hydrocarbon stress and injury may also affect performance of a vapor phase bioreactor. Batch kinetic studies on the biodegradation of toluene by P. Putida 54G will be compared to those obtained from continuous culture studies for both suspended and biofilm cultures of the same microorganism. These results will be compared to the activity of the P. putida 54G biofilm in a vapor phase bioreactor to evaluate the impact of hydrocarbon stress and injury on biodegradative processes

Knudsen cell vaporization of rare earth nitrides: enthalpy of vaporization of HoN098

International Nuclear Information System (INIS)

Brown, R.C.; Clark, N.J.

1975-01-01

The enthalpy of vaporization of HoN 0 . 98 was measured by the weight-loss Knudsen cell technique using Motzfeldt-Whitman extrapolations to zero orifice area. A third-law enthalpy of vaporization of HoN 0 . 98 of 155.9 +- 5 kcal mole -1 was obtained compared to a second-law value of 162.0 +- 5 kcal mole -1 . Similar measurements on the nitrides of samarium, erbium, and ytterbium gave third-law enthalpies of vaporization of 126.8 +-- 5 kcal mole -1 ; 159.6 +- 5 kcal mole -1 , and 121.0 +- 5 kcal mole -1 , respectively. 7 tables

Vapor pressures and vapor compositions in equilibrium with hypostoichiometric plutonium dioxide at high temperatures

International Nuclear Information System (INIS)

Green, D.W.; Fink, J.K.; Leibowitz, L.

1982-01-01

Vapor pressures and vapor compositions have been calculated for 1500 less than or equal to T less than or equal to 4000 0 K. Thermodynamic functions for the condensed phase and for each of the gaseous species were combined with an oxygen-potential model extended into the liquid region to obtain the partial pressures of O 2 , O, Pu, PuO and PuO 2 . The calculated oxygen pressures increase very rapidly as stoichiometry is approached. At least part of this increase is a consequence of the exclusion of Pu 6 + from the oxygen-potential model. No reliable method was found to estimate the importance of this ion. As a result of large oxygen potentials at high temperatures, extremely high total pressures that produced unreasonably high vapor densities were calculated. The highest temperature was therefore limited to 400 K, and the range of oxygen-to-metal ratios was limited to 1.994 to 1.70. These calculations show that vapor in equilibrium with hypostoichiometric plutonium dioxide is poorly approximated as PuO 2 for most of the temperture and composition range of interest. The vapor is much more oxygen-rich than the condensed phase. Implications for the (U,Pu)O/sub 2-x/ system are discussed

Vapor pressure measured with inflatable plastic bag

Science.gov (United States)

1965-01-01

Deflated plastic bag in a vacuum chamber measures initial low vapor pressures of materials. The bag captures the test sample vapors and visual observation of the vapor-inflated bag under increasing external pressures yields pertinent data.

Large-Scale Fabrication of Boron Nitride Nanotubes via a Facile Chemical Vapor Reaction Route and Their Cathodoluminescence Properties

Directory of Open Access Journals (Sweden)

Zhong Bo

2011-01-01

Full Text Available Abstract Cylinder- and bamboo-shaped boron nitride nanotubes (BNNTs have been synthesized in large scale via a facile chemical vapor reaction route using ammonia borane as a precursor. The structure and chemical composition of the as-synthesized BNNTs are extensively characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and selected-area electron diffraction. The cylinder-shaped BNNTs have an average diameter of about 100 nm and length of hundreds of microns, while the bamboo-shaped BNNTs are 100–500 nm in diameter with length up to tens of microns. The formation mechanism of the BNNTs has been explored on the basis of our experimental observations and a growth model has been proposed accordingly. Ultraviolet–visible and cathodoluminescence spectroscopic analyses are performed on the BNNTs. Strong ultraviolet emissions are detected on both morphologies of BNNTs. The band gap of the BNNTs are around 5.82 eV and nearly unaffected by tube morphology. There exist two intermediate bands in the band gap of BNNTs, which could be distinguishably assigned to structural defects and chemical impurities. Additional file 1 Click here for file

Multi-scale learning based segmentation of glands in digital colonrectal pathology images.

Science.gov (United States)

Gao, Yi; Liu, William; Arjun, Shipra; Zhu, Liangjia; Ratner, Vadim; Kurc, Tahsin; Saltz, Joel; Tannenbaum, Allen

2016-02-01

Digital histopathological images provide detailed spatial information of the tissue at micrometer resolution. Among the available contents in the pathology images, meso-scale information, such as the gland morphology, texture, and distribution, are useful diagnostic features. In this work, focusing on the colon-rectal cancer tissue samples, we propose a multi-scale learning based segmentation scheme for the glands in the colon-rectal digital pathology slides. The algorithm learns the gland and non-gland textures from a set of training images in various scales through a sparse dictionary representation. After the learning step, the dictionaries are used collectively to perform the classification and segmentation for the new image.

Temperature dependences of saturated vapor pressure and the enthalpy of vaporization of n-pentyl esters of dicarboxylic acids

Science.gov (United States)

Portnova, S. V.; Krasnykh, E. L.; Levanova, S. V.

2016-05-01

The saturated vapor pressures and enthalpies of vaporization of n-pentyl esters of linear C2-C6 dicarboxylic acids are determined by the transpiration method in the temperature range of 309.2-361.2 K. The dependences of enthalpies of vaporization on the number of carbon atoms in the molecule and on the retention indices have been determined. The predictive capabilities of the existing calculation schemes for estimation of enthalpy of vaporization of the studied compounds have been analyzed.

Vapor-droplet flow equations

International Nuclear Information System (INIS)

Crowe, C.T.

1975-01-01

General features of a vapor-droplet flow are discussed and the equations expressing the conservation of mass, momentum, and energy for the vapor, liquid, and mixture using the control volume approach are derived. The phenomenological laws describing the exchange of mass, momentum, and energy between phases are also reviewed. The results have application to development of water-dominated geothermal resources

Significado prognóstico das micrometástases nos linfonodos do carcinoma colorretal: detecção imunoistoquímica com anticorpos anticitoqueratina AE1/AE3

Directory of Open Access Journals (Sweden)

Rogério Tadeu Palma

Full Text Available OBJETIVOS: Identificar por imunoistoquímica eventuais micrometástases nos linfonodos regionais previamente considerados livres pelo exame histopatológico convencional e avaliar a influência do comprometimento destes linfonodos na sobrevivência dos doentes com carcinoma colorretal extirpado com intenção curativa. MÉTODO: Foram estudados 51 doentes portadores de carcinoma colorretal nos estádios A (13 casos e B (38 casos, segundo a classificação de Dukes. Um total de 501 linfonodos previamente considerados livres pelo exame histopatológico convencional foi investigado por meio de técnica imunoistoquímica com anticorpos monoclonais anticitoqueratina AE1/AE3 para identificar células epiteliais. Cada bloco previamente fixado em formalina e embebido em parafina foi seccionado em três partes, obtendo-se de cada uma delas três cortes com espessura de 4 milimícron cada. RESULTADOS: Em seis doentes (11,7% no estádio B de Dukes, células neoplásicas foram identificadas em sete linfonodos do mesocolo (1,4% previamente considerados livres de neoplasia pelo exame histopatológico convencional. Em um enfermo, a micrometástase era representada por aglomerado celular, enquanto que nos outros cinco doentes as micrometástases eram constituídas por células isoladas. A sobrevivência dos enfermos com micrometástases linfonodais foi menor do que a dos doentes com linfonodos não comprometidos, porém sem atingir diferença significativa. CONCLUSÕES: O método imunoistoquímico pode ser empregado com sucesso na detecção de células neoplásicas em linfonodos previamente considerados livres pelo exame histopatológico convencional. O acometimento dos linfonodos regionais por micrometástases não influenciou a sobrevivência dos doentes com carcinoma colorretal extirpado.

Micrometer scale guidance of mesenchymal stem cells to form structurally oriented large-scale tissue engineered cartilage.

Science.gov (United States)

Chou, Chih-Ling; Rivera, Alexander L; Williams, Valencia; Welter, Jean F; Mansour, Joseph M; Drazba, Judith A; Sakai, Takao; Baskaran, Harihara

2017-09-15

Current clinical methods to treat articular cartilage lesions provide temporary relief of the symptoms but fail to permanently restore the damaged tissue. Tissue engineering, using mesenchymal stem cells (MSCs) combined with scaffolds and bioactive factors, is viewed as a promising method for repairing cartilage injuries. However, current tissue engineered constructs display inferior mechanical properties compared to native articular cartilage, which could be attributed to the lack of structural organization of the extracellular matrix (ECM) of these engineered constructs in comparison to the highly oriented structure of articular cartilage ECM. We previously showed that we can guide MSCs undergoing chondrogenesis to align using microscale guidance channels on the surface of a two-dimensional (2-D) collagen scaffold, which resulted in the deposition of aligned ECM within the channels and enhanced mechanical properties of the constructs. In this study, we developed a technique to roll 2-D collagen scaffolds containing MSCs within guidance channels in order to produce a large-scale, three-dimensional (3-D) tissue engineered cartilage constructs with enhanced mechanical properties compared to current constructs. After rolling the MSC-scaffold constructs into a 3-D cylindrical structure, the constructs were cultured for 21days under chondrogenic culture conditions. The microstructure architecture and mechanical properties of the constructs were evaluated using imaging and compressive testing. Histology and immunohistochemistry of the constructs showed extensive glycosaminoglycan (GAG) and collagen type II deposition. Second harmonic generation imaging and Picrosirius red staining indicated alignment of neo-collagen fibers within the guidance channels of the constructs. Mechanical testing indicated that constructs containing the guidance channels displayed enhanced compressive properties compared to control constructs without these channels. In conclusion, using a novel

Underwater electrical wire explosion: Shock wave from melting being overtaken by shock wave from vaporization

Science.gov (United States)

Li, Liuxia; Qian, Dun; Zou, Xiaobing; Wang, Xinxin

2018-05-01

The shock waves generated by an underwater electrical wire explosion were investigated. A microsecond time-scale pulsed current source was used to trigger the electrical explosion of copper wires with a length of 5 cm and a diameter of 200 μm. The energy-storage capacitor was charged to a relatively low energy so that the energy deposited onto the wire was not large enough to fully vaporize the whole wire. Two shock waves were recorded with a piezoelectric gauge that was located at a position of 100 mm from the exploding wire. The first and weak shock wave was confirmed to be the contribution from wire melting, while the second and stronger shock wave was the contribution from wire vaporization. The phenomenon whereby the first shock wave generated by melting being overtaken by the shock wave due to vaporization was observed.

What Good is Raman Water Vapor Lidar?

Science.gov (United States)

Whitman, David

2011-01-01

Raman lidar has been used to quantify water vapor in the atmosphere for various scientific studies including mesoscale meteorology and satellite validation. Now the international networks of NDACC and GRUAN have interest in using Raman water vapor lidar for detecting trends in atmospheric water vapor concentrations. What are the data needs for addressing these very different measurement challenges. We will review briefly the scientific needs for water vapor accuracy for each of these three applications and attempt to translate that into performance specifications for Raman lidar in an effort to address the question in the title of "What good is Raman water vapor Iidar."

Industrial Scale Synthesis of Carbon Nanotubes Via Fluidized Bed Chemical Vapor Deposition: A Senior Design Project

Science.gov (United States)

Smith, York R.; Fuchs, Alan; Meyyappan, M.

2010-01-01

Senior year chemical engineering students designed a process to produce 10 000 tonnes per annum of single wall carbon nanotubes (SWNT) and also conducted bench-top experiments to synthesize SWNTs via fluidized bed chemical vapor deposition techniques. This was an excellent pedagogical experience because it related to the type of real world design…

Ion vapor deposition and its application

International Nuclear Information System (INIS)

Bollinger, H.; Schulze, D.; Wilberg, R.

1981-01-01

Proceeding from the fundamentals of ion vapor deposition the characteristic properties of ion-plated coatings are briefly discussed. Examples are presented of successful applications of ion-plated coatings such as coatings with special electrical and dielectric properties, coatings for corrosion prevention, and coatings for improving the surface properties. It is concluded that ion vapor deposition is an advantageous procedure in addition to vapor deposition. (author)

Discovery of natural gain amplification in the 10-micrometer carbon dioxide laser bands on Mars - A natural laser

Science.gov (United States)

Mumma, M. J.; Buhl, D.; Chin, G.; Deming, D.; Espenak, F.; Kostiuk, T.; Zipoy, D.

1981-01-01

Fully resolved intensity profiles of various lines in the carbon dioxide band at 10.4 micrometers have been measured on Mars with an infrared heterodyne spectrometer. Analysis of the line shapes shows that the Mars atmosphere exhibits positive gain in these lines. The detection of natural optical gain amplification enables identification of these lines as a definite natural laser.

A Lithium Vapor Box Divertor Similarity Experiment

Science.gov (United States)

Cohen, Robert A.; Emdee, Eric D.; Goldston, Robert J.; Jaworski, Michael A.; Schwartz, Jacob A.

2017-10-01

A lithium vapor box divertor offers an alternate means of managing the extreme power density of divertor plasmas by leveraging gaseous lithium to volumetrically extract power. The vapor box divertor is a baffled slot with liquid lithium coated walls held at temperatures which increase toward the divertor floor. The resulting vapor pressure differential drives gaseous lithium from hotter chambers into cooler ones, where the lithium condenses and returns. A similarity experiment was devised to investigate the advantages offered by a vapor box divertor design. We discuss the design, construction, and early findings of the vapor box divertor experiment including vapor can construction, power transfer calculations, joint integrity tests, and thermocouple data logging. Heat redistribution of an incident plasma-based heat flux from a typical linear plasma device is also presented. This work supported by DOE Contract No. DE-AC02-09CH11466 and The Princeton Environmental Institute.

Beeswax–chitosan emulsion coated paper with enhanced water vapor barrier efficiency

International Nuclear Information System (INIS)

Zhang, Weiwei; Xiao, Huining; Qian, Liying

2014-01-01

Graphical abstract: - Highlights: • The water vapor barrier efficiency of paper was enhanced via green-based emulsion coating. • Extremely high lipid content in the emulsion coating layer was firstly utilized to reduce WVTR in emulsion-based film. • A controlled WVTR of beeswax–chitosan emulsion coating could be obtained by dying at specific temperature. - Abstract: For lipid–hydrocolloid emulsion based film, the increase of lipid amount would improve its water vapor barrier property, but also reduce the mechanical strength of the film in the meantime thus leading to a compromised lipid content in the film. However, when the emulsion is coated on paper surface, more lipid could be used for emulsion preparation to enhance the moisture resistance without considering the weakened strength of the film induced by lipid, because the mechanical properties of emulsion coated paper is mainly governed by the strength of base paper instead of the coating layer. In this study, beeswax–chitosan emulsion was first prepared and then coated on paper surface to improve paper's water vapor barrier and water resistance properties. The range and variance analysis of orthogonal test design showed that the order of priorities of the factors accordingly was beeswax solid content, drying temperature and chitosan concentration. The effect of drying temperature on water vapor transmission rate (WVTR) and water contact angle of coated paper was further investigated using 1.2 wt% chitosan and 96% beeswax solid content in the coating layer. The results indicated that water vapor barrier property was in accordance with the density of the coating layer. Atomic force microscope (AFM) was also used to characterize the surface morphology and explain the hydrophobicity of beeswax–chitosan coated paper. It was found that surface beeswax particles melted to wrinkle at high drying temperatures, while roughness values maintained at micro-scale over the temperature range investigated

A Regional-Scale Assessment of Satellite Derived Precipitable Water Vapor Across The Amazon Basin

Science.gov (United States)

DeLiberty, Tracy; Callahan, John; Guillory, Anthony R.; Jedlovec, Gary

2000-01-01

Atmospheric water vapor is widely recognized as a key climate variable, linking an assortment of poorly understood and complex processes. It is a major element of the hydrological cycle and provides a mechanism for energy exchange among many of the Earth system components. Reducing uncertainty in our current knowledge of water vapor and its role in the climate system requires accurate measurement, improved modeling techniques, and long-term prediction. Satellites have the potential to satisfy these criteria, as well as provide high resolution measurements that are not available from conventional sources. The focus of this paper is to examine the temporal and mesoscale variations of satellite derived precipitable water vapor (PW) across the Amazon Basin. This region is pivotal in the functioning of the global climate system through its abundant release of latent heat associated with heavy precipitation events. In addition, anthropogenic deforestation and biomass burning activities in recent decades are altering the conditions of the atmosphere, especially in the planetary boundary layer. A physical split-window (PSW) algorithm estimates PW using images from the GOES satellites along with the NCEP/NCAR Reanalysis data that provides the first guess information. Retrievals are made at a three-hourly time step during daylight hours in the Amazon Basin and surrounding areas for the months of June and October in 1988 (dry year) and 1995 (wet year). Spatially continuous fields are generated 5 times daily at 12Z, 15Z, 18Z, 21Z, and 00Z. These fields are then averaged to create monthly and 3 hourly monthly grids. Overall, the PSW estimates PW reasonable well in the Amazon with MAE ranging from 3.0 - 9.0 mm and MAE/observed mean around 20% in comparison to radiosonde observations. The distribution of PW generally mimics that of precipitation. Maximum values (42 - 52 mm) are located in the Northwest whereas minimum values (18 - 27 mm) are found along Brazil's East coast. Aside

Hanford soil partitioning and vapor extraction study

International Nuclear Information System (INIS)

Yonge, D.; Hossain, A.; Cameron, R.; Ford, H.; Storey, C.

1996-07-01

This report describes the testing and results of laboratory experiments conducted to assist the carbon tetrachloride soil vapor extraction project operating in the 200 West Area of the Hanford Site in Richland, Washington. Vapor-phase adsorption and desorption testing was performed using carbon tetrachloride and Hanford Site soils to estimate vapor-soil partitioning and reasonably achievable carbon tetrachloride soil concentrations during active vapor extractions efforts at the 200 West Area. (CCl 4 is used in Pu recovery from aqueous streams.)

Vapor trap for liquid metal

Energy Technology Data Exchange (ETDEWEB)

Watanabe, T

1968-05-22

In a pipe system which transfers liquid metal, inert gas (cover gas) is packed above the surface of the liquid metal to prevent oxidization of the liquid. If the metal vapor is contained in such cover gas, the circulating system of the cover gas is blocked due to condensation of liquid metal inside the system. The present invention relates to an improvement in vapor trap to remove the metal vapor from the cover gas. The trap consists of a cylindrical outer body, an inlet nozzle which is deeply inserted inside the outer body and has a number of holes to inject the cove gas into the body, metal mesh or steel wool which covers the exterior of the nozzle and on which the condensation of the metal gas takes place, and a heater wire hich is wound around the nozzle to prevent condensation of the metal vapor at the inner peripheral side of the mesh.

Vapor Extraction/Bioventing Sequential Treatment of Soil Contaminated with Volatile and SemiVolatile Hydrocarbon Mixtures

NARCIS (Netherlands)

Malina, G.; Grotenhuis, J.T.C.; Rulkens, W.H.

2002-01-01

A cost-effective removal strategy was studied in bench-scale columns that involved vapor extraction and bioventing sequential treatment of toluene- and decane-contaminated soil. The effect of operating mode on treatment performance was examined at a continuous air flow and consecutively at two

Low-dose vaporized cannabis significantly improves neuropathic pain.

Science.gov (United States)

Wilsey, Barth; Marcotte, Thomas; Deutsch, Reena; Gouaux, Ben; Sakai, Staci; Donaghe, Haylee

2013-02-01

We conducted a double-blind, placebo-controlled, crossover study evaluating the analgesic efficacy of vaporized cannabis in subjects, the majority of whom were experiencing neuropathic pain despite traditional treatment. Thirty-nine patients with central and peripheral neuropathic pain underwent a standardized procedure for inhaling medium-dose (3.53%), low-dose (1.29%), or placebo cannabis with the primary outcome being visual analog scale pain intensity. Psychoactive side effects and neuropsychological performance were also evaluated. Mixed-effects regression models demonstrated an analgesic response to vaporized cannabis. There was no significant difference between the 2 active dose groups' results (P > .7). The number needed to treat (NNT) to achieve 30% pain reduction was 3.2 for placebo versus low-dose, 2.9 for placebo versus medium-dose, and 25 for medium- versus low-dose. As these NNTs are comparable to those of traditional neuropathic pain medications, cannabis has analgesic efficacy with the low dose being as effective a pain reliever as the medium dose. Psychoactive effects were minimal and well tolerated, and neuropsychological effects were of limited duration and readily reversible within 1 to 2 hours. Vaporized cannabis, even at low doses, may present an effective option for patients with treatment-resistant neuropathic pain. The analgesia obtained from a low dose of delta-9-tetrahydrocannabinol (1.29%) in patients, most of whom were experiencing neuropathic pain despite conventional treatments, is a clinically significant outcome. In general, the effect sizes on cognitive testing were consistent with this minimal dose. As a result, one might not anticipate a significant impact on daily functioning. Published by Elsevier Inc.

Finite Element Analysis Modeling of Chemical Vapor Deposition of Silicon Carbide

Science.gov (United States)

2014-06-19

concentrations. This is the method by which species adsorb to the surface of the substrate. The movement resulting from diffusion is governed by...itself. This can be treacherous, however. The mesh is what the entire finite element method is built upon. If the movement of the backbone has... Brownian Motion Algorithm for Tow Scale Modeling of Chemical Vapor Infiltration. Computational Materials Science, 1871-1878. !178 23. Wang, C. & D

Aerodynamic Factors Responsible for the Deaggregation of Carrier-Free Drug Powders to form Micrometer and Submicrometer Aerosols

Science.gov (United States)

Longest, P. Worth; Son, Yoen-Ju; Holbrook, Landon; Hindle, Michael

2013-01-01

Purpose The objective of this study was to employ in vitro experiments combined with computational fluid dynamics (CFD) analysis to determine which aerodynamic factors were most responsible for deaggregating carrier-free powders to form micrometer and submicrometer aerosols from a capsule-based platform. Methods Eight airflow passages were evaluated for deaggregation of the aerosol including a standard constricted tube, impaction surface, 2D mesh, inward radial jets, and newly proposed 3D grids and rod arrays. CFD simulations were implemented to evaluate existing and new aerodynamic factors for deaggregation and in vitro experiments were used to evaluate performance of each inhaler. Results For the carrier-free formulation considered, turbulence was determined to be the primary deaggregation mechanism. A strong quantitative correlation was established between the mass median diameter (MMD) and newly proposed non-dimensional specific dissipation (NDSD) factor, which accounts for turbulent energy, inverse of the turbulent length scale, and exposure time. A 3D rod array design with unidirectional elements maximized NDSD and produced the best deaggregation with MMD<1μm. Conclusions The new NDSD parameter can be used to develop highly effective dry powder inhalers like the 3D rod array that can efficiently produce submicrometer aerosols for next-generation respiratory drug delivery applications. PMID:23471640

Mechanics of gas-vapor bubbles

NARCIS (Netherlands)

Hao, Yue; Zhang, Yuhang; Prosperetti, Andrea

2017-01-01

Most bubbles contain a mixture of vapor and incondensible gases. While the limit cases of pure vapor and pure gas bubbles are well studied, much less is known about the more realistic case of a mixture. The bubble contents continuously change due to the combined effects of evaporation and

Vapor pressures and thermophysical properties of selected hexenols and recommended vapor pressure for hexan-1-ol

Czech Academy of Sciences Publication Activity Database

Štejfa, V.; Fulem, Michal; Růžička, K.; Matějka, P.

2015-01-01

Roč. 402, Sep (2015), 18-29 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : alcohols * vapor pressure * heat capacity * ideal - gas thermodynamic properties * vaporization enthalpy Subject RIV: BJ - Thermodynamics Impact factor: 1.846, year: 2015

Water vapor profiling using microwave radiometry

Science.gov (United States)

Wang, J. R.; Wilheit, T. T.

1988-01-01

Water vapor is one of the most important constituents in the Earth's atmosphere. Its spatial and temporal variations affect a wide spectrum of meteorological phenomena ranging from the formation of clouds to the development of severe storms. The passive microwave technique offers an excellent means for water vapor measurements. It can provide both day and night coverage under most cloud conditions. Two water vapor absorption features, at 22 and 183 GHz, were explored in the past years. The line strengths of these features differ by nearly two orders of magnitude. As a consequence, the techniques and the final products of water vapor measurements are also quite different. The research effort in the past few years was to improve and extend the retrieval algorithm to the measurements of water vapor profiles under cloudy conditions. In addition, the retrieval of total precipitable water using 183 GHz measurements, but in a manner analogous to the use of 22 GHz measurements, to increase measurement sensitivity for atmospheres of very low moisture content was also explored.

Effect of precursor supply on structural and morphological characteristics of fe nanomaterials synthesized via chemical vapor condensation method.

Science.gov (United States)

Ha, Jong-Keun; Ahn, Hyo-Jun; Kim, Ki-Won; Nam, Tae-Hyun; Cho, Kwon-Koo

2012-01-01

Various physical, chemical and mechanical methods, such as inert gas condensation, chemical vapor condensation, sol-gel, pulsed wire evaporation, evaporation technique, and mechanical alloying, have been used to synthesize nanoparticles. Among them, chemical vapor condensation (CVC) has the benefit of its applicability to almost all materials because a wide range of precursors are available for large-scale production with a non-agglomerated state. In this work, Fe nanoparticles and nanowires were synthesized by chemical vapor condensation method using iron pentacarbonyl (Fe(CO)5) as the precursor. The effect of processing parameters on the microstructure, size and morphology of Fe nanoparticles and nanowires were studied. In particular, we investigated close correlation of size and morphology of Fe nanoparticles and nanowires with atomic quantity of inflow precursor into the electric furnace as the quantitative analysis. The atomic quantity was calculated by Boyle's ideal gas law. The Fe nanoparticles and nanowires with various diameter and morphology have successfully been synthesized by the chemical vapor condensation method.

HANFORD CHEMICAL VAPORS WORKER CONCERNS and EXPOSURE EVALUATION

International Nuclear Information System (INIS)

ANDERSON, T.J.

2006-01-01

Chemical vapor emissions from underground hazardous waste storage tanks on the Hanford site in eastern Washington State are a potential concern because workers enter the tank farms on a regular basis for waste retrievals, equipment maintenance, and surveillance. Tank farm contractors are in the process of retrieving all remaining waste from aging single-shell tanks, some of which date to World War II, and transferring it to newer double-shell tanks. During the waste retrieval process, tank farm workers are potentially exposed to fugitive chemical vapors that can escape from tank headspaces and other emission points. The tanks are known to hold more than 1,500 different species of chemicals, in addition to radionuclides. Exposure assessments have fully characterized the hazards from chemical vapors in half of the tank farms. Extensive sampling and analysis has been done to characterize the chemical properties of hazardous waste and to evaluate potential health hazards of vapors at the ground surface, where workers perform maintenance and waste transfer activities. Worker concerns. risk communication, and exposure assessment are discussed, including evaluation of the potential hazards of complex mixtures of chemical vapors. Concentrations of vapors above occupational exposure limits-(OEL) were detected only at exhaust stacks and passive breather filter outlets. Beyond five feet from the sources, vapors disperse rapidly. No vapors have been measured above 50% of their OELs more than five feet from the source. Vapor controls are focused on limited hazard zones around sources. Further evaluations of vapors include analysis of routes of exposure and thorough analysis of nuisance odors

The nuclear liquid-vapor phase transition: Equilibrium between phases or free decay in vacuum?

International Nuclear Information System (INIS)

Phair, L.; Moretto, L.G.; Elliott, J.B.; Wozniak, G.J.

2002-01-01

Recent analyses of multifragmentation in terms of Fisher's model and the related construction of a phase diagram brings forth the problem of the true existence of the vapor phase and the meaning of its associated pressure. Our analysis shows that a thermal emission picture is equivalent to a Fisher-like equilibrium description which avoids the problem of the vapor and explains the recently observed Boltzmann-like distribution of the emission times. In this picture a simple Fermi gas thermometric relation is naturally justified. Low energy compound nucleus emission of intermediate mass fragments is shown to scale according to Fisher's formula and can be simultaneously fit with the much higher energy ISiS multifragmentation data

Vapor and gas sampling of single-shell tank 241-B-102 using the in situ vapor sampling system

International Nuclear Information System (INIS)

Lockrem, L.L.

1997-01-01

The Vapor Issue Resolution Program tasked the Vapor Team (the team) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-B-102. This document presents sampling data resulting from the April 18, 1996 sampling of SST 241-B-102. Analytical results will be presented in a separate report issued by Pacific Northwest National Laboratory (PNNL), which supplied and analyzed the sampling media. The team, consisting of Sampling and Mobile Laboratories (SML) and Special Analytical Studies (SAS) personnel, used the vapor sampling system (VSS) to collect representative samples of the air, gases, and vapors from the headspace of SST 241-B-102 with sorbent traps and SUMMA canisters

Atmospheric pressure chemical vapor deposition (APCVD) grown bi-layer graphene transistor characteristics at high temperature

KAUST Repository

Qaisi, Ramy M.; Smith, Casey; Hussain, Muhammad Mustafa

2014-01-01

We report the characteristics of atmospheric chemical vapor deposition grown bilayer graphene transistors fabricated on ultra-scaled (10 nm) high-κ dielectric aluminum oxide (Al2O3) at elevated temperatures. We observed that the drive current increased by >400% as temperature increased from room temperature to 250 °C. Low gate leakage was maintained for prolonged exposure at 100 °C but increased significantly at temperatures >200 °C. These results provide important insights for considering chemical vapor deposition graphene on aluminum oxide for high temperature applications where low power and high frequency operation are required. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Atmospheric pressure chemical vapor deposition (APCVD) grown bi-layer graphene transistor characteristics at high temperature

KAUST Repository

Qaisi, Ramy M.

2014-05-15

We report the characteristics of atmospheric chemical vapor deposition grown bilayer graphene transistors fabricated on ultra-scaled (10 nm) high-κ dielectric aluminum oxide (Al2O3) at elevated temperatures. We observed that the drive current increased by >400% as temperature increased from room temperature to 250 °C. Low gate leakage was maintained for prolonged exposure at 100 °C but increased significantly at temperatures >200 °C. These results provide important insights for considering chemical vapor deposition graphene on aluminum oxide for high temperature applications where low power and high frequency operation are required. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A dispersion safety factor for LNG vapor clouds

Energy Technology Data Exchange (ETDEWEB)

Vílchez, Juan A. [TIPs – Trámites, Informes y Proyectos, SL, Llenguadoc 10, 08030 Barcelona (Spain); Villafañe, Diana [Centre d’Estudis del Risc Tecnològic (CERTEC), Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Catalonia (Spain); Casal, Joaquim, E-mail: joaquim.casal@upc.edu [Centre d’Estudis del Risc Tecnològic (CERTEC), Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Catalonia (Spain)

2013-02-15

Highlights: ► We proposed a new parameter: the dispersion safety factor (DSF). ► DSF is the ratio between the distance reached by the LFL and that reached by the visible cloud. ► The results for the DSF agree well with the evidence from large scale experiments. ► Two expressions have been proposed to calculate DSF as a function of H{sub R}. ► The DSF may help in indicating the danger of ignition of a LNG vapor cloud. -- Abstract: The growing importance of liquefied natural gas (LNG) to global energy demand has increased interest in the possible hazards associated with its storage and transportation. Concerning the event of an LNG spill, a study was performed on the relationship between the distance at which the lower flammability limit (LFL) concentration occurs and that corresponding to the visible contour of LNG vapor clouds. A parameter called the dispersion safety factor (DSF) has been defined as the ratio between these two lengths, and two expressions are proposed to estimate it. During an emergency, the DSF can be a helpful parameter to indicate the danger of cloud ignition and flash fire.

A dispersion safety factor for LNG vapor clouds

International Nuclear Information System (INIS)

Vílchez, Juan A.; Villafañe, Diana; Casal, Joaquim

2013-01-01

Highlights: ► We proposed a new parameter: the dispersion safety factor (DSF). ► DSF is the ratio between the distance reached by the LFL and that reached by the visible cloud. ► The results for the DSF agree well with the evidence from large scale experiments. ► Two expressions have been proposed to calculate DSF as a function of H R . ► The DSF may help in indicating the danger of ignition of a LNG vapor cloud. -- Abstract: The growing importance of liquefied natural gas (LNG) to global energy demand has increased interest in the possible hazards associated with its storage and transportation. Concerning the event of an LNG spill, a study was performed on the relationship between the distance at which the lower flammability limit (LFL) concentration occurs and that corresponding to the visible contour of LNG vapor clouds. A parameter called the dispersion safety factor (DSF) has been defined as the ratio between these two lengths, and two expressions are proposed to estimate it. During an emergency, the DSF can be a helpful parameter to indicate the danger of cloud ignition and flash fire

Analyses on Water Vapor Resource in Chengdu City

Science.gov (United States)

Liu, B.; Xiao, T.; Wang, C.; Chen, D.

2017-12-01

Chengdu is located in the Sichuan basin, and it is the most famous inland city in China. With suitable temperatures and rainfall, Chengdu is the most livable cities in China. With the development of urban economy and society, the population has now risen to 16 million, and it will up to 22 million in 2030. This will cause the city water resources demand, and the carrying capacity of water resources become more and more serious. In order to improve the contradiction between urban waterlogging and water shortage, sponge city planning was proposed by Chengdu government, and this is of great practical significance for promoting the healthy development of the city. Base on the reanalysis data from NCEP during 2007-2016, the characters of Water Vapor Resources was analyzed, and the main contents of this research are summarized as follows: The water vapor resource in Chengdu plain is more than that in Southeast China and less in Northwest China. The annual average water vapor resource is approximately 160 mm -320 mm, and the water vapor resource in summer can reach 3 times in winter. But the annual average precipitation in Chengdu is about 800 mm -1200 mm and it is far greater than the water vapor resource, this is because of the transport of water vapor. Using the formula of water vapor flux, the water vapor in Chengdu is comes from the west and the south, and the value is around 50kg/(ms). Base on the calculation of boundary vapor budget, the water vapor transport under 500hPa accounted for 97% of the total. Consider the water vapor transport, transformation and urban humidification effect, the Water Vapor Resource in Chengdu is 2500mm, and it can be used by artificial precipitation enhancement. Therefore, coordinated development of weather modification and sponge city construction, the shortage of water resources in Chengdu plain can be solved. Key words: Chengdu; Sponge city; Water vapor resource; Precipitation; Artificial precipitation enhancement Acknowledgements

Boiling performance and material robustness of modified surfaces with multi scale structures for fuel cladding development

Energy Technology Data Exchange (ETDEWEB)

Jo, HangJin; Kim, Jin Man [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Yeom, Hwasung [Department of Nuclear Engineering and Engineering physics, UW-Madison, Madison, WI 53706, Unities States (United States); Lee, Gi Cheol [Department of Mechanical Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Park, Hyun Sun, E-mail: hejsunny@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Kiyofumi, Moriyama; Kim, Moo Hwan [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Sridharan, Kumar; Corradini, Michael [Department of Nuclear Engineering and Engineering physics, UW-Madison, Madison, WI 53706, Unities States (United States)

2015-09-15

Highlights: • We improved boiling performance and material robustness using surface modification. • We combined micro/millimeter post structures and nanoparticles with heat treatments. • Compactly-arranged micrometer posts had improved boiling performance. • CHF increased significantly due to capillary pumping by the deposited NP layers. • Sintering procedure increased mechanical strength of the NP coating surface. - Abstract: By regulating the geometrical characteristics of multi-scale structures and by adopting heat treatment for protective layer of nanoparticles (NPs), we improved critical heat flux (CHF), boiling heat transfer (BHT), and mechanical robustness of the modified surface. We fabricated 1-mm and 100-μm post structures and deposited NPs on the structured surface as a nano-scale structured layer and protective layer at the same time, then evaluated the CHF and BHT and material robustness of the modified surfaces. On the structured surfaces without NPs, the surface with compactly-arranged micrometer posts had improved CHF (118%) and BHT (41%). On the surface with structures on which NPs had been deposited, CHF increased significantly (172%) due to capillary pumping by the deposited NP layers. The heat treatment improved robustness of coating layer in comparison to the one of before heat treatment. In particular, low-temperature sintering increased the hardness of the modified surface by 140%. The increased mechanical strength of the NP coating is attributed to reduction in coating porosity during sintering. The combination of micrometer posts structures and sintered NP coating can increase the safety, efficiency and reliability of advanced nuclear fuel cladding.

Boiling performance and material robustness of modified surfaces with multi scale structures for fuel cladding development

International Nuclear Information System (INIS)

Jo, HangJin; Kim, Jin Man; Yeom, Hwasung; Lee, Gi Cheol; Park, Hyun Sun; Kiyofumi, Moriyama; Kim, Moo Hwan; Sridharan, Kumar; Corradini, Michael

2015-01-01

Highlights: • We improved boiling performance and material robustness using surface modification. • We combined micro/millimeter post structures and nanoparticles with heat treatments. • Compactly-arranged micrometer posts had improved boiling performance. • CHF increased significantly due to capillary pumping by the deposited NP layers. • Sintering procedure increased mechanical strength of the NP coating surface. - Abstract: By regulating the geometrical characteristics of multi-scale structures and by adopting heat treatment for protective layer of nanoparticles (NPs), we improved critical heat flux (CHF), boiling heat transfer (BHT), and mechanical robustness of the modified surface. We fabricated 1-mm and 100-μm post structures and deposited NPs on the structured surface as a nano-scale structured layer and protective layer at the same time, then evaluated the CHF and BHT and material robustness of the modified surfaces. On the structured surfaces without NPs, the surface with compactly-arranged micrometer posts had improved CHF (118%) and BHT (41%). On the surface with structures on which NPs had been deposited, CHF increased significantly (172%) due to capillary pumping by the deposited NP layers. The heat treatment improved robustness of coating layer in comparison to the one of before heat treatment. In particular, low-temperature sintering increased the hardness of the modified surface by 140%. The increased mechanical strength of the NP coating is attributed to reduction in coating porosity during sintering. The combination of micrometer posts structures and sintered NP coating can increase the safety, efficiency and reliability of advanced nuclear fuel cladding

A technique to depress desflurane vapor pressure.

Science.gov (United States)

Brosnan, Robert J; Pypendop, Bruno H

2006-09-01

To determine whether the vapor pressure of desflurane could be decreased by using a solvent to reduce the anesthetic molar fraction in a solution (Raoult's Law). We hypothesized that such an anesthetic mixture could produce anesthesia using a nonprecision vaporizer instead of an agent-specific, electronically controlled, temperature and pressure compensated vaporizer currently required for desflurane administration. One healthy adult female dog. Propylene glycol was used as a solvent for desflurane, and the physical characteristics of this mixture were evaluated at various molar concentrations and temperatures. Using a circle system with a breathing bag attached at the patient end and a mechanical ventilator to simulate respiration, an in-circuit, nonprecision vaporizer containing 40% desflurane and 60% propylene glycol achieved an 11.5% +/- 1.0% circuit desflurane concentration with a 5.2 +/- 0.4 (0 = off, 10 = maximum) vaporizer setting. This experiment was repeated with a dog attached to the breathing circuit under spontaneous ventilation with a fresh gas flow of 0.5 L minute(-1). Anesthesia was maintained for over 2 hours at a mean vaporizer setting of 6.2 +/- 0.4, yielding mean inspired and end-tidal desflurane concentrations of 8.7% +/- 0.5% and 7.9% +/- 0.7%, respectively. Rather than alter physical properties of vaporizers to suit a particular anesthetic agent, this study demonstrates that it is also possible to alter physical properties of anesthetic agents to suit a particular vaporizer. However, propylene glycol may not prove an ideal solvent for desflurane because of its instability in solution and substantial-positive deviation from Raoult's Law.

Multi-scale simulation for homogenization of cement media

International Nuclear Information System (INIS)

Abballe, T.

2011-01-01

To solve diffusion problems on cement media, two scales must be taken into account: a fine scale, which describes the micrometers wide microstructures present in the media, and a work scale, which is usually a few meters long. Direct numerical simulations are almost impossible because of the huge computational resources (memory, CPU time) required to assess both scales at the same time. To overcome this problem, we present in this thesis multi-scale resolution methods using both Finite Volumes and Finite Elements, along with their efficient implementations. More precisely, we developed a multi-scale simulation tool which uses the SALOME platform to mesh domains and post-process data, and the parallel calculation code MPCube to solve problems. This SALOME/MPCube tool can solve automatically and efficiently multi-scale simulations. Parallel structure of computer clusters can be use to dispatch the more time-consuming tasks. We optimized most functions to account for cement media specificities. We presents numerical experiments on various cement media samples, e.g. mortar and cement paste. From these results, we manage to compute a numerical effective diffusivity of our cement media and to reconstruct a fine scale solution. (author) [fr

Perspective: Highly stable vapor-deposited glasses

Science.gov (United States)

Ediger, M. D.

2017-12-01

This article describes recent progress in understanding highly stable glasses prepared by physical vapor deposition and provides perspective on further research directions for the field. For a given molecule, vapor-deposited glasses can have higher density and lower enthalpy than any glass that can be prepared by the more traditional route of cooling a liquid, and such glasses also exhibit greatly enhanced kinetic stability. Because vapor-deposited glasses can approach the bottom of the amorphous part of the potential energy landscape, they provide insights into the properties expected for the "ideal glass." Connections between vapor-deposited glasses, liquid-cooled glasses, and deeply supercooled liquids are explored. The generality of stable glass formation for organic molecules is discussed along with the prospects for stable glasses of other types of materials.

Fabrication of fiber-reinforced composites by chemical vapor infiltration

Energy Technology Data Exchange (ETDEWEB)

Besmann, T.M.; McLaughlin, J.C. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Probst, K.J.; Anderson, T.J. [Univ. of Florida, Gainesville, FL (United States). Dept. of Chemical Engineering; Starr, T.L. [Georgia Inst. of Tech., Atlanta, GA (United States). Dept. of Materials Science and Engineering

1997-12-01

Silicon carbide-based heat exchanger tubes are of interest to energy production and conversion systems due to their excellent high temperature properties. Fiber-reinforced SiC is of particular importance for these applications since it is substantially tougher than monolithic SiC, and therefore more damage and thermal shock tolerant. This paper reviews a program to develop a scaled-up system for the chemical vapor infiltration of tubular shapes of fiber-reinforced SiC. The efforts include producing a unique furnace design, extensive process and system modeling, and experimental efforts to demonstrate tube fabrication.

Lab-scale hydrogen peroxide data from ECBC

Data.gov (United States)

U.S. Environmental Protection Agency — Data from small lab scale tests conducted at ECBC. It contains efficacy data as well as data on env conditions such as temperature, RH, and hydrogen peroxide vapor...

Bionanomaterials and Bioinspired Nanostructures for Selective Vapor Sensing

Science.gov (United States)

2013-04-03

agricultural crops. To meet the requirements for these and other demanding applications, new sensing approaches with improved sensor selectivity are required...of these vapors with key side- chain amino acids. DNT-binding peptide receptors were further conjugated to an oligo(ethylene glycol) hydrogel for vapor...coefficient for DNT over TNT vapor. Vapor-phase binding performance was attributed to the ability of the oligo(ethylene glycol) hydrogel to maintain the

Measurement of air and VOC vapor fluxes during gas-driven soil remediation: bench-scale experiments.

Science.gov (United States)

Kim, Heonki; Kim, Taeyun; Shin, Seungyeop; Annable, Michael D

2012-09-04

In this laboratory study, an experimental method was developed for the quantitative analyses of gas fluxes in soil during advective air flow. One-dimensional column and two- and three-dimensional flow chamber models were used in this study. For the air flux measurement, n-octane vapor was used as a tracer, and it was introduced in the air flow entering the physical models. The tracer (n-octane) in the gas effluent from the models was captured for a finite period of time using a pack of activated carbon, which then was analyzed for the mass of n-octane. The air flux was calculated based on the mass of n-octane captured by the activated carbon and the inflow concentration. The measured air fluxes are in good agreement with the actual values for one- and two-dimensional model experiments. Using both the two- and three-dimensional models, the distribution of the air flux at the soil surface was measured. The distribution of the air flux was found to be affected by the depth of the saturated zone. The flux and flux distribution of a volatile contaminant (perchloroethene) was also measured by using the two-dimensional model. Quantitative information of both air and contaminant flux may be very beneficial for analyzing the performance of gas-driven subsurface remediation processes including soil vapor extraction and air sparging.

Vapor and gas sampling of single-shell tank 241-U-104 using the in situ vapor sampling system

International Nuclear Information System (INIS)

Lockrem, L.L.

1997-01-01

The Vapor Issue.Resolution Program tasked the Vapor Team (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-U-104. This document presents In Situ Vapor Sampling System (ISVS) data resulting from the July 16, 1996 sampling of SST 241-U-104. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which supplied and analyzed the sample media

Vapor and gas sampling of single-shell tank 241-S-103 using the in situ vapor sampling system

International Nuclear Information System (INIS)

Lockrem, L.L.

1997-01-01

The Vapor Issue Resolution Program tasked the Vapor Team (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-S-103. This document presents In Situ Vapor Sampling System (ISVS) data resulting from the June 12, 1996 sampling of SST 241-S-103. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which supplied and analyzed the sample media

Vapor and gas sampling of single-shell tank 241-S-106 using the in situ vapor sampling system

International Nuclear Information System (INIS)

Lockrem, L.L.

1997-01-01

The Vapor Issue Resolution Program tasked the Vapor Team (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-S-106. This document presents In Situ vapor Sampling System (ISVS) data resulting from the June 13, 1996 sampling of SST 241-S-106. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which'supplied and analyzed the sample media

Cumulus convection and the terrestrial water-vapor distribution

Science.gov (United States)

Donner, Leo J.

1988-01-01

Cumulus convection plays a significant role in determining the structure of the terrestrial water vapor field. Cumulus convection acts directly on the moisture field by condensing and precipitating water vapor and by redistributing water vapor through cumulus induced eddy circulations. The mechanisms by which cumulus convection influences the terrestrial water vapor distribution is outlined. Calculations using a theory due to Kuo is used to illustrate the mechanisms by which cumulus convection works. Understanding of these processes greatly aids the ability of researchers to interpret the seasonal and spatial distribution of atmospheric water vapor by providing information on the nature of sources and sinks and the global circulation.

Vapor pumps and gas-driven machines

International Nuclear Information System (INIS)

Guillet, R.

1991-01-01

The vapor pump, patented in 1979 by Gaz de France, is an additional mass and heat exchanger which uses the combustion air of fuel-burning machines as an additional cold source. This cold source is preheated and, above all, humidified before reaching the burner, by means of the residual sensible and latent heat in the combustion products of the fuel-burning process. This final exchanger thus makes it possible, in many cases, to recover all the gross calorific value of natural gas, even when the combustion products leave the process at a wet temperature greater than 60 0 C, the maximum dew point of the products of normal combustion. Another significant advantage of the vapor pump being worth highlighting is the selective recycling of water vapor by the vapor pump which reduces the adiabatic combustion temperature and the oxygen concentration in the combustion air, two factors which lead to considerable reductions in nitrogen oxides formation, hence limiting atmospheric pollution. Alongside a wide range of configurations which make advantageous use of the vapor pump in association with gas-driven machines and processes, including gas turbines, a number of boiler plant installations are also presented [fr

Thermodynamics and Kinetics of Silicate Vaporization

Science.gov (United States)

Jacobson, Nathan S.; Costa, Gustavo C. C.

2015-01-01

Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The vaporization behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low vapor pressures. This can be circumvented by using a reducing agent to boost the vapor pressure without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to vaporization. The measurement of these barriers, as encompassed in a vaporization coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.

Modeling UTLS water vapor: Transport/Chemistry interactions

International Nuclear Information System (INIS)

Gulstad, Line

2005-01-01

This thesis was initially meant to be a study on the impact on chemistry and climate from UTLS water vapor. However, the complexity of the UTLS water vapor and its recent changes turned out to be a challenge by it self. In the light of this, the overall motivation for the thesis became to study the processes controlling UTLS water vapor and its changes. Water vapor is the most important greenhouse gas, involved in important climate feedback loops. Thus, a good understanding of the chemical and dynamical behavior of water vapor in the atmosphere is crucial for understanding the climate changes in the last century. Additionally, parts of the work was motivated by the development of a coupled climate chemistry model based on the CAM3 model coupled with the Chemical Transport Model Oslo CTM2. The future work will be concentrated on the UTLS water vapor impact on chemistry and climate. We are currently studying long term trends in UTLS water vapor, focusing on identification of the different processes involved in the determination of such trends. The study is based on natural as well as anthropogenic climate forcings. The ongoing work on the development of a coupled climate chemistry model will continue within our group, in collaboration with Prof. Wei-Chyung Wang at the State University of New York, Albany. Valuable contacts with observational groups are established during the work on this thesis. These collaborations will be continued focusing on continuous model validation, as well as identification of trends and new features in UTLS water vapor, and other tracers in this region. (Author)

Calculating the enthalpy of vaporization for ionic liquid clusters.

Science.gov (United States)

Kelkar, Manish S; Maginn, Edward J

2007-08-16

Classical atomistic simulations are used to compute the enthalpy of vaporization of a series of ionic liquids composed of 1-alkyl-3-methylimidazolium cations paired with the bis(trifluoromethylsulfonyl)imide anion. The calculations show that the enthalpy of vaporization is lowest for neutral ion pairs. The enthalpy of vaporization increases by about 40 kJ/mol with the addition of each ion pair to the vaporizing cluster. Non-neutral clusters have much higher vaporization enthalpies than their neutral counterparts and thus are not expected to make up a significant fraction of volatile species. The enthalpy of vaporization increases slightly as the cation alkyl chain length increases and as temperature decreases. The calculated vaporization enthalpies are consistent with two sets of recent experimental measurements as well as with previous atomistic simulations.

Monatomic chemical-vapor-deposited graphene membranes bridge a half-millimeter-scale gap.

Science.gov (United States)

Lee, Choong-Kwang; Hwangbo, Yun; Kim, Sang-Min; Lee, Seoung-Ki; Lee, Seung-Mo; Kim, Seong-Su; Kim, Kwang-Seop; Lee, Hak-Joo; Choi, Byung-Ik; Song, Chang-Kyu; Ahn, Jong-Hyun; Kim, Jae-Hyun

2014-03-25

One of the main concerns in nanotechnology is the utilization of nanomaterials in macroscopic applications without losing their extreme properties. In an effort to bridge the gap between the nano- and macroscales, we propose a clever fabrication method, the inverted floating method (IFM), for preparing freestanding chemical-vapor-deposited (CVD) graphene membranes. These freestanding membranes were then successfully suspended over a gap a half-millimeter in diameter. To understand the working principle of IFM, high-speed photography and white light interferometry were used to characterize and analyze the deformation behaviors of the freestanding graphene membranes in contact with a liquid during fabrication. Some nanoscale configurations in the macroscopic graphene membranes were able to be characterized by simple optical microscopy. The proposed IFM is a powerful approach to investigating the macroscopic structures of CVD graphene and enables the exploitation of freestanding CVD graphene for device applications.

Prediction of vapor pressure and heats of vaporization of edible oil/fat compounds by group contribution

DEFF Research Database (Denmark)

Ceriani, Roberta; Gani, Rafiqul; Liu, Y.A.

2013-01-01

In the present work, a group contribution method is proposed for the estimation of vapor pressures and heats of vaporization of organic liquids found in edible fat/oil and biofuel industries as a function of temperature. The regression of group contribution parameters was based on an extensive...

Comparative study of the vapor analytes of trinitrotoluene (TNT)

Science.gov (United States)

Edge, Cindy C.; Gibb, Julie; Dugan, Regina E.

1998-12-01

Trinitrotoluene (TNT) is a high explosive used in most antipersonnel and antitank landmines. The Institute for Biological Detection Systems (IBDS) has developed a quantitative vapor delivery system, termed olfactometer, for conducting canine olfactory research. The research is conducted utilizing dynamic conditions, therefore, it is imperative to evaluate the headspace of TNT to ensure consistency with the dynamic generation of vapor. This study quantified the vapor headspace of military- grade TNT utilizing two different vapor generated methodologies, static and dynamic, reflecting differences between field and laboratory environments. Static vapor collection, which closely mimics conditions found during field detection, is defined as vapor collected in an open-air environment at ambient temperature. Dynamic vapor collection incorporates trapping of gases from a high flow vapor generation cell used during olfactometer operation. Analysis of samples collected by the two methodologies was performed by gas chromatography/mass spectrometry and the results provided information with regard to the constituents detected. However, constituent concentration did vary between the sampling methods. This study provides essential information regarding the vapor constituents associated with the TNT sampled using different sampling methods. These differences may be important in determining the detection signature dogs use to recognize TNT.

Micrometer sized immobilization of protein molecules onto quartz, silicium and gold.

Science.gov (United States)

Petersen, Steffen B.; Neves-Petersen, Maria Teresa; Klitgaard, Søren; Duroux, Meg Crookshanks

2006-02-01

We demonstrate that ultraviolet light can be used to make sterically oriented covalent immobilization of a large variety of protein molecules onto either gold or thiolated quartz or silicium. The reaction mechanism behind the reported new technology involves light induced breakage of disulphide bridges in proteins upon UV illumination of nearby aromatic amino acids, resulting in the formation of free, reactive thiol groups that will form covalent bonds with thiol reactive surfaces. The protein molecules in general retain their function. The size of the immobilization spot is determined by the dimension of the UV beam. In principle, the spot size may be as small as 1 micrometer or less. We have developed the necessary technology for preparing large protein arrays of enzymes and fragments of monoclonal antibodies. Dedicated Image Processing Software has been developed for making quality assessment of the protein arrays. A multitude of important application areas such as drug carriers and drug delivery, bioelectronics, carbon nanotubes, nanoparticles as well as protein glue are discussed.

Using Femtosecond Laser Subcellular Surgery as a Tool to Study Cell Biology

Energy Technology Data Exchange (ETDEWEB)

Shen, N; Colvin, M E; Huser, T

2007-02-27

Research on cellular function and regulation would be greatly advanced by new instrumentation using methods to alter cellular processes with spatial discrimination on the nanometer-scale. We present a novel technique for targeting submicrometer sized organelles or other biologically important regions in living cells using femtosecond laser pulses. By tightly focusing these pulses beneath the cell membrane, we can vaporize cellular material inside the cell through nonlinear optical processes. This technique enables non-invasive manipulation of the physical structure of a cell with sub-micrometer resolution. We propose to study the role mitochondria play in cell proliferation and apoptosis. Our technique provides a unique tool for the study of cell biology.

Surface measurements of upper tropospheric water vapor isotopic composition on the Chajnantor Plateau, Chile

Science.gov (United States)

Galewsky, Joseph; Rella, Christopher; Sharp, Zachary; Samuels, Kimberly; Ward, Dylan

2011-09-01

Simultaneous, real-time measurements of atmospheric water vapor mixing ratio and isotopic composition (δD and δ18O) were obtained using cavity ringdown spectroscopy on the arid Chajnantor Plateau in the subtropical Chilean Andes (elevation 5080 m or 550 hPa; latitude 23°S) during July and August 2010. The measurements show surface water vapor mixing ratio as low as 215 ppmv, δD values as low as -540‰, and δ18O values as low as -68‰, which are the lowest atmospheric water vapor δ values reported from Earth's surface. The results are consistent with previous measurements from the base of the tropical tropopause layer (TTL) and suggest large-scale subsidence of air masses from the upper troposphere to the Earth's surface. The range of measurements is consistent with condensation under conditions of ice supersaturation and mixing with moister air from the lower troposphere that has been processed through shallow convection. Diagnostics using reanalysis data show that the extreme aridity of the Chajnantor Plateau is controlled by condensation in the upper tropical troposphere.

Evidence of water vapor in excess of saturation in the atmosphere of Mars.

Science.gov (United States)

Maltagliati, L; Montmessin, F; Fedorova, A; Korablev, O; Forget, F; Bertaux, J-L

2011-09-30

The vertical distribution of water vapor is key to the study of Mars' hydrological cycle. To date, it has been explored mainly through global climate models because of a lack of direct measurements. However, these models assume the absence of supersaturation in the atmosphere of Mars. Here, we report observations made using the SPICAM (Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars) instrument onboard Mars Express that provide evidence of the frequent presence of water vapor in excess of saturation, by an amount far surpassing that encountered in Earth's atmosphere. This result contradicts the widespread assumption that atmospheric water on Mars cannot exist in a supersaturated state, directly affecting our long-term representation of water transport, accumulation, escape, and chemistry on a global scale.

Estimating enthalpy of vaporization from vapor pressure using Trouton's rule.

Science.gov (United States)

MacLeod, Matthew; Scheringer, Martin; Hungerbühler, Konrad

2007-04-15

The enthalpy of vaporization of liquids and subcooled liquids at 298 K (delta H(VAP)) is an important parameter in environmental fate assessments that consider spatial and temporal variability in environmental conditions. It has been shown that delta H(VAP)P for non-hydrogen-bonding substances can be estimated from vapor pressure at 298 K (P(L)) using an empirically derived linear relationship. Here, we demonstrate that the relationship between delta H(VAP)and PL is consistent with Trouton's rule and the ClausiusClapeyron equation under the assumption that delta H(VAP) is linearly dependent on temperature between 298 K and the boiling point temperature. Our interpretation based on Trouton's rule substantiates the empirical relationship between delta H(VAP) degree and P(L) degrees for non-hydrogen-bonding chemicals with subcooled liquid vapor pressures ranging over 15 orders of magnitude. We apply the relationship between delta H(VAP) degrees and P(L) degrees to evaluate data reported in literature reviews for several important classes of semivolatile environmental contaminants, including polycyclic aromatic hydrocarbons, chlorobenzenes, polychlorinated biphenyls and polychlorinated dibenzo-dioxins and -furans and illustrate the temperature dependence of results from a multimedia model presented as a partitioning map. The uncertainty associated with estimating delta H(VAP)degrees from P(L) degrees using this relationship is acceptable for most environmental fate modeling of non-hydrogen-bonding semivolatile organic chemicals.

Recommended Vapor Pressure of Solid Naphthalen

Czech Academy of Sciences Publication Activity Database

Růžička, K.; Fulem, Michal; Růžička, V.

2005-01-01

Roč. 50, - (2005), s. 1956-1970 ISSN 0021-9568 Institutional research plan: CEZ:AV0Z10100521 Keywords : solid naphthalene * vapor pressure * enthalpy of vaporization * enthalpy of fusion Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.610, year: 2005

SOIL VAPOR EXTRACTION TECHNOLOGY: REFERENCE HANDBOOK

Science.gov (United States)

Soil vapor extraction (SVE) systems are being used in Increasing numbers because of the many advantages these systems hold over other soil treatment technologies. SVE systems appear to be simple in design and operation, yet the fundamentals governing subsurface vapor transport ar...

Bionanomaterials and Bioinspired Nanostructures for Selective Vapor Sensing

Science.gov (United States)

Potyrailo, Radislav; Naik, Rajesh R.

2013-07-01

At present, monitoring of air at the workplace, in urban environments, and on battlefields; exhaled air from medical patients; air in packaged food containers; and so forth can be accomplished with different types of analytical instruments. Vapor sensors have their niche in these measurements when an unobtrusive, low-power, and cost-sensitive technical solution is required. Unfortunately, existing vapor sensors often degrade their vapor-quantitation accuracy in the presence of high levels of interferences and cannot quantitate several components in complex gas mixtures. Thus, new sensing approaches with improved sensor selectivity are required. This technological task can be accomplished by the careful design of sensing materials with new performance properties and by coupling these materials with the suitable physical transducers. This review is focused on the assessment of the capabilities of bionanomaterials and bioinspired nanostructures for selective vapor sensing. We demonstrate that these sensing materials can operate with diverse transducers based on electrical, mechanical, and optical readout principles and can provide vapor-response selectivity previously unattainable by using other sensing materials. This ability for selective vapor sensing provides opportunities to significantly impact the major directions in development and application scenarios of vapor sensors.

Continuous and simultaneous measurements of precipitation and vapor isotopes over two monsoon seasons during 2016-2017 in Singapore

Science.gov (United States)

Jackisch, D.; He, S.; Ong, M. R.; Goodkin, N.

2017-12-01

Water isotopes are important tracers of climate dynamics and their measurement can provide valuable insights into the relationship between isotopes and atmospheric parameters and overall convective activities. While most studies provide data on daily or even monthly time scales, high-temporal in-situ stable isotope measurements are scarce, especially in the tropics. In this study, we presented δ18O and δ2H values in precipitation and vapor continuously and simultaneously measured using laser spectroscopy in Singapore during the 2016/2017 Northeast (NE) Asian monsoon and 2017 Southwest (SW) Asian monsoon. We found that δ-values of precipitation and vapor exhibit quite different patterns during individual events, although there is a significant correlation between the δ-values of precipitation and of vapor. δ-values in precipitation during individual precipitation events show a distinct V-shape pattern, with the lowest isotope values observed in the middle of the event. However, isotopes in water vapor mostly show an L-shape and are characterized by a gradual decrease with the onset of rainfall. The difference in δ-values of precipitation and vapor is generally constant during the early stage of the events but gradually increases near the end. It is likely that vapor and precipitation are closer to equilibrium at the early stage of a rain event, but diverge at the later stages. This divergence can be largely attributed to the evaporation of raindrops. We notice a frequent drop in d-excess of precipitation, whereas d-excess in vapor increases. In addition, a significant correlation exists between outgoing longwave radiation (OLR) and isotopes in both precipitation and vapor, suggesting an influence of regional convective activity.

Reaching (sub-)micrometer resolution of photo-immobilized proteins using diffracted light beams

DEFF Research Database (Denmark)

Skovsen, Esben; Neves Petersen, Teresa; Petersen, Steffen B.

2008-01-01

, with dimensions as small as a few micrometers. The ultimate size of the immobilized spots is dependent on the focal area of the UV beam. The technology involves light induced formation of free, reactive thiol groups in molecules containing aromatic residues nearby disulphide bridges. It is not only limited...... to immobilizing molecules according to conventional patterns like microarrays, as any bitmap motif can virtually be used a template for patterning. We now show that molecules (proteins) can be immobilized on a surface with any arbitrary pattern according to diffraction patterns of light. The pattern of photo......-immobilized proteins reproduces the diffraction pattern of light expected with the optical setup. Immobilising biomolecules according to diffraction patterns of light will allow achievement of smaller patterns with higher resolution. The flexibility of this new technology leads to any patterns of photo...

Positioning of the rf potential minimum line of a linear Paul trap with micrometer precision

DEFF Research Database (Denmark)

Herskind, Peter Fønss; Dantan, Aurélien; Albert, Magnus

2009-01-01

We demonstrate a general technique to achieve a precise radial displacement of the nodal line of the radiofrequency (rf) field in a linear Paul trap. The technique relies on the selective adjustment of the load capacitance of the trap electrodes, achieved through the addition of capacitors...... to the basic resonant rf circuit used to drive the trap. Displacements of up to ~100 µm with micrometer precision are measured using a combination of fluorescence images of ion Coulomb crystals and coherent coupling of such crystals to a mode of an optical cavity. The displacements are made without measurable...

Decreased respiratory symptoms in cannabis users who vaporize

Directory of Open Access Journals (Sweden)

Barnwell Sara

2007-04-01

Full Text Available Abstract Cannabis smoking can create respiratory problems. Vaporizers heat cannabis to release active cannabinoids, but remain cool enough to avoid the smoke and toxins associated with combustion. Vaporized cannabis should create fewer respiratory symptoms than smoked cannabis. We examined self-reported respiratory symptoms in participants who ranged in cigarette and cannabis use. Data from a large Internet sample revealed that the use of a vaporizer predicted fewer respiratory symptoms even when age, sex, cigarette smoking, and amount of cannabis used were taken into account. Age, sex, cigarettes, and amount of cannabis also had significant effects. The number of cigarettes smoked and amount of cannabis used interacted to create worse respiratory problems. A significant interaction revealed that the impact of a vaporizer was larger as the amount of cannabis used increased. These data suggest that the safety of cannabis can increase with the use of a vaporizer. Regular users of joints, blunts, pipes, and water pipes might decrease respiratory symptoms by switching to a vaporizer

Optical Sensor for Diverse Organic Vapors at ppm Concentration Ranges

Directory of Open Access Journals (Sweden)

Dora M. Paolucci

2011-03-01

Full Text Available A broadly responsive optical organic vapor sensor is described that responds to low concentrations of organic vapors without significant interference from water vapor. Responses to several classes of organic vapors are highlighted, and trends within classes are presented. The relationship between molecular properties (vapor pressure, boiling point, polarizability, and refractive index and sensor response are discussed.

Vaporization of elemental mercury from pools of molten lead at low concentrations

International Nuclear Information System (INIS)

Greene, G.A.; Finfrock, C.C.

2000-01-01

Should coolant accidentally be lost to the APT (Accelerator Production of Tritium) blanket and target, and the decay heat in the target be deposited in the surrounding blanket by thermal radiation, temperatures in the blanket modules could exceed structural limits and cause a physical collapse of the blanket modules into a non-coolable geometry. Such a sequence of unmitigated events could result in some melting of the APT blanket and create the potential for the release of mercury into the target-blanket cavity air space. Experiments were conducted which simulate such hypothetical accident conditions in order to measure the rate of vaporization of elemental mercury from pools of molten lead to quantify the possible severe accident source term for the APT blanket region. Molten pools of from 0.01% to 0.10% mercury in lead were prepared under inert conditions. Experiments were conducted, which varied in duration from several hours to as long as a month, to measure the mercury vaporization from the lead pools. The melt pools and gas atmospheres were held fixed at 340 C during the tests. Parameters which were varied in the tests included the mercury concentration, gas flow rate over the melt and agitation of the melt, gas atmosphere composition and the addition of aluminum to the melt. The vaporization of mercury was found to scale roughly linearly with the concentration of mercury in the pool. Variations in the gas flow rates were not found to have any effect on the mass transfer, however agitation of the melt by a submerged stirrer did enhance the mercury vaporization rate. The rate of mercury vaporization with an argon (inert) atmosphere was found to exceed that for an air (oxidizing) atmosphere by as much as a factor of from ten to 20; the causal factor in this variation was the formation of an oxide layer over the melt pool with the air atmosphere which served to retard mass transfer across the melt-atmosphere interface. Aluminum was introduced into the melt to

40 CFR 52.787 - Gasoline transfer vapor control.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.787... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer vapor control. (a) Gasoline means any petroleum distillate having a Reid vapor pressure of 4 pounds or greater...

Generalized modeling of multi-component vaporization/condensation phenomena for multi-phase-flow analysis

International Nuclear Information System (INIS)

Morita, K.; Fukuda, K.; Tobita, Y.; Kondo, Sa.; Suzuki, T.; Maschek, W.

2003-01-01

A new multi-component vaporization/condensation (V/C) model was developed to provide a generalized model for safety analysis codes of liquid metal cooled reactors (LMRs). These codes simulate thermal-hydraulic phenomena of multi-phase, multi-component flows, which is essential to investigate core disruptive accidents of LMRs such as fast breeder reactors and accelerator driven systems. The developed model characterizes the V/C processes associated with phase transition by employing heat transfer and mass-diffusion limited models for analyses of relatively short-time-scale multi-phase, multi-component hydraulic problems, among which vaporization and condensation, or simultaneous heat and mass transfer, play an important role. The heat transfer limited model describes the non-equilibrium phase transition processes occurring at interfaces, while the mass-diffusion limited model is employed to represent effects of non-condensable gases and multi-component mixture on V/C processes. Verification of the model and method employed in the multi-component V/C model of a multi-phase flow code was performed successfully by analyzing a series of multi-bubble condensation experiments. The applicability of the model to the accident analysis of LMRs is also discussed by comparison between steam and metallic vapor systems. (orig.)

Estimating evaporative vapor generation from automobiles based on parking activities

International Nuclear Information System (INIS)

Dong, Xinyi; Tschantz, Michael; Fu, Joshua S.

2015-01-01

A new approach is proposed to quantify the evaporative vapor generation based on real parking activity data. As compared to the existing methods, two improvements are applied in this new approach to reduce the uncertainties: First, evaporative vapor generation from diurnal parking events is usually calculated based on estimated average parking duration for the whole fleet, while in this study, vapor generation rate is calculated based on parking activities distribution. Second, rather than using the daily temperature gradient, this study uses hourly temperature observations to derive the hourly incremental vapor generation rates. The parking distribution and hourly incremental vapor generation rates are then adopted with Wade–Reddy's equation to estimate the weighted average evaporative generation. We find that hourly incremental rates can better describe the temporal variations of vapor generation, and the weighted vapor generation rate is 5–8% less than calculation without considering parking activity. - Highlights: • We applied real parking distribution data to estimate evaporative vapor generation. • We applied real hourly temperature data to estimate hourly incremental vapor generation rate. • Evaporative emission for Florence is estimated based on parking distribution and hourly rate. - A new approach is proposed to quantify the weighted evaporative vapor generation based on parking distribution with an hourly incremental vapor generation rate

The non-Newtonian heat and mass transport of He 2 in porous media used for vapor-liquid phase separation. Ph.D. Thesis

Science.gov (United States)

Yuan, S. W. K.

1985-01-01

This investigation of vapor-liquid phase separation (VLPS) of He 2 is related to long-term storage of cryogenic liquid. The VLPS system utilizes porous plugs in order to generate thermomechanical (thermo-osmotic) force which in turn prevents liquid from flowing out of the cryo-vessel (e.g., Infrared Astronomical Satellite). An apparatus was built and VLPS data were collected for a 2 and a 10 micrometer sintered stainless steel plug and a 5 to 15 micrometer sintered bronze plug. The VLPS data obtained at high temperature were in the nonlinear turbulent regime. At low temperature, the Stokes regime was approached. A turbulent flow model was developed, which provides a phenomenological description of the VLPS data. According to the model, most of the phase separation data are in the turbulent regime. The model is based on concepts of the Gorter-Mellink transport involving the mutual friction known from the zero net mass flow (ZNMF) studies. The latter had to be modified to obtain agreement with the present experimental VLPS evidence. In contrast to the well-known ZNMF mode, the VLPS results require a geometry dependent constant (Gorter-Mellink constant). A theoretical interpretation of the phenomenological equation for the VLPS data obtained, is based on modelling of the dynamics of quantized vortices proposed by Vinen. In extending Vinen's model to the VLPS transport of He 2 in porous media, a correlation between the K*(GM) and K(p) was obtained which permits an interpretation of the present findings. As K(p) is crucial, various methods were introduced to measure the permeability of the porous media at low temperatures. Good agreement was found between the room temperature and the low temperature K(p)-value of the plugs.

Evaporation at microscopic scale and at high heat flux

International Nuclear Information System (INIS)

Janecek, V.

2012-01-01

This thesis theoretically investigates the transport processes in the vicinity of the triple gas-liquid-solid contact line and its impact on macroscopic evaporation. In the first part of the thesis, the hydrodynamics close to the contact line at partial wetting is studied. Specifically, evaporation into the atmosphere of pure vapor driven by heating of the substrate is considered. The question of singularity relaxation is addressed. The main finding of the thesis is that the Kelvin effect (dependence of saturation temperature on pressure) is sufficient by itself to relax the hydrodynamic contact line singularity. The proposed microregion (the contact line vicinity) model for small interface slopes is solved numerically. Asymptotic solutions are found for some specific cases. The governing length scales of the problem are identified and the multi-scale nature of the phenomenon is addressed. Parametric studies revealing the role of the thermal resistance of vapor-liquid interface, slip length, thermo-capillary term, the vapor recoil and surface forces are also performed. An extension of the lubrication approximation for high slopes of the gas-liquid interface at evaporation is discussed. In the second part of the thesis, the previously established microregion model is coupled to a simplified single vapor bubble growth numerical simulation. The bubble departure from the heater at boiling is also studied. It was proposed in the thesis, that under high heat loads, the increase of the apparent contact angle causes the vapor bubble to spread over the heated substrate. Such a behavior may cause the heater dry-out that occurs during the boiling crisis. (author) [fr

40 CFR 52.255 - Gasoline transfer vapor control.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.255... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.255 Gasoline transfer vapor control. (a) “Gasoline” means any petroleum distillate having a Reid vapor pressure of 4 pounds or greater...

33 CFR 154.826 - Vapor compressors and blowers.

Science.gov (United States)

2010-07-01

...) Excessive shaft bearing temperature. (d) If a centrifugal compressor, fan, or lobe blower handles vapor in... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vapor compressors and blowers....826 Vapor compressors and blowers. (a) Each inlet and outlet to a compressor or blower which handles...

Low temperature fabrication of conductive silver lines and dots via transfer-printing and nanoimprinting lithography techniques

International Nuclear Information System (INIS)

Wu, Chun-Chang; Hsu, Steve Lien-Chung; Chiu, Ching-Wei; Wu, Jung-Tang

2013-01-01

In this work, we have developed novel methods to fabricate conductive silver tracks and dots directly from silver nitrate solution by transfer-printing and nanoimprinting lithography techniques, which are inexpensive and can be scaled down to the nanometer scale. The silver nitrate precursor can be reduced in ethylene glycol vapor to form silver at low temperatures. Energy dispersive spectrometric analysis results indicate that the silver nitrate has been converted to silver completely. In order to obtain smooth and continuous conductive patterned silver features with high resolution, the silver lines with widths of a few tens of micrometers to nanometers were patterned by using a spin-coating approach. Using a 14 M silver nitrate solution, continuous silver conductive lines with a resistivity of 8.45 × 10 −5 Ω cm has been produced. (paper)

Effect of granosan vapors on mitosis

Energy Technology Data Exchange (ETDEWEB)

Lishenko, N P; Lishenko, I D

1974-01-01

Experiments were performed to determine the effects of granosan on the germination of vetch seeds. Vetch seeds were stored from 4-6 days in ethyl mercuric chloride vapors. Results indicated that the vapors caused a sharp decrease in germination and caused chromosomal aberrations during the anaphase.

Vapor-deposited non-crystalline phase vs ordinary glasses and supercooled liquids: Subtle thermodynamic and kinetic differences

International Nuclear Information System (INIS)

Bhattacharya, Deepanjan; Sadtchenko, Vlad

2015-01-01

Vapor deposition of molecules on a substrate often results in glassy materials of high kinetic stability and low enthalpy. The extraordinary properties of such glasses are attributed to high rates of surface diffusion during sample deposition, which makes it possible for constituents to find a configuration of much lower energy on a typical laboratory time scale. However, the exact nature of the resulting phase and the mechanism of its formation are not completely understood. Using fast scanning calorimetry technique, we show that out-of-equilibrium relaxation kinetics and possibly the enthalpy of vapor-deposited films of toluene and ethylbenzene, archetypical fragile glass formers, are distinct from those of ordinary supercooled phase even when the deposition takes place at temperatures above the ordinary glass softening transition temperatures. These observations along with the absolute enthalpy dependences on deposition temperatures support the conjecture that the vapor-deposition may result in formation of non-crystalline phase of unique structural, thermodynamic, and kinetic properties

Soil Vapor Extraction and Bioventing Test Work Plan for the MOGAS Site, Myrtle Beach Air Force Base, South Carolina

National Research Council Canada - National Science Library

1995-01-01

This work plan presents an evaluation of soil vapor extraction (SVE) and bioventing, and describes the SVE pilot scale and bioventing activities to be conducted to extract and treat soil gas at Installation Restoration Program (IRP...

Molecular dynamics study of the vaporization of an ionic drop

Science.gov (United States)

Galamba, N.

2010-09-01

The melting of a microcrystal in vacuum and subsequent vaporization of a drop of NaCl were studied through molecular dynamics simulations with the Born-Mayer-Huggins-Tosi-Fumi rigid-ion effective potential. The vaporization was studied for a single isochor at increasing temperatures until the drop completely vaporized, and gaseous NaCl formed. Examination of the vapor composition shows that the vapor of the ionic drop and gaseous NaCl are composed of neutral species, the most abundant of which, ranging from simple NaCl monomers (ion pairs) to nonlinear polymers, (NanCln)n=2-4. The enthalpies of sublimation, vaporization, and dissociation of the different vapor species are found to be in reasonable agreement with available experimental data. The decrease of the enthalpy of vaporization of the vapor species, with the radius of the drop decrease, accounts for a larger fraction of trimers and tetramers than that inferred from experiments. Further, the rhombic dimer is significantly more abundant than its linear isomer although the latter increases with the temperature. The present results suggest that both trimers and linear dimers may be important to explain the vapor pressure of molten NaCl at temperatures above 1500 K.

21 CFR 888.4220 - Cement monomer vapor evacuator.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement monomer vapor evacuator. 888.4220 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4220 Cement monomer vapor evacuator. (a) Identification. A cement monomer vapor evacuator is a device intended for use during surgery to contain or remove...

Evaluation of water vapor distribution in general circulation models using satellite observations

Science.gov (United States)

Soden, Brian J.; Bretherton, Francis P.

1994-01-01

This paper presents a comparison of the water vapor distribution obtained from two general circulation models, the European Centre for Medium-Range Weather Forecasts (ECMWF) model and the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM), with satellite observations of total precipitable water (TPW) from Special Sensor Microwave/Imager (SSM/I) and upper tropospheric relative humidity (UTH) from GOES. Overall, both models are successful in capturing the primary features of the observed water vapor distribution and its seasonal variation. For the ECMWF model, however, a systematic moist bias in TPW is noted over well-known stratocumulus regions in the eastern subtropical oceans. Comparison with radiosonde profiles suggests that this problem is attributable to difficulties in modeling the shallowness of the boundary layer and large vertical water vapor gradients which characterize these regions. In comparison, the CCM is more successful in capturing the low values of TPW in the stratocumulus regions, although it tends to exhibit a dry bias over the eastern half of the subtropical oceans and a corresponding moist bias in the western half. The CCM also significantly overestimates the daily variability of the moisture fields in convective regions, suggesting a problem in simulating the temporal nature of moisture transport by deep convection. Comparison of the monthly mean UTH distribution indicates generally larger discrepancies than were noted for TPW owing to the greater influence of large-scale dynamical processes in determining the distribution of UTH. In particular, the ECMWF model exhibits a distinct dry bias along the Intertropical Convergence Zone (ITCZ) and a moist bias over the subtropical descending branches of the Hadley cell, suggesting an underprediction in the strength of the Hadley circulation. The CCM, on the other hand, demonstrates greater discrepancies in UTH than are observed for the ECMWF model, but none that are as

Prediction of the vapor pressure and vaporization enthalpy of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids.

Science.gov (United States)

Diedenhofen, Michael; Klamt, Andreas; Marsh, Kenneth; Schäfer, Ansgar

2007-09-07

The vapor pressures and vaporization enthalpies of a series of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids have been predicted with two different approaches using the COSMO-RS method and quantum chemical gas phase calculations. While the calculated enthalpies are in good agreement with the experimental data, COSMO-RS seems to underestimate the vapor pressures by roughly 0.5-4 log units dependent on the IL and approach used.

Ticosonde CFH at Costa Rica: A Seasonal Climatology of Tropical UT-LS Water Vapor and Inter-Comparisons with MLS and CALIPSO

Science.gov (United States)

Selkirk, Henry B.; Voemel, Holger; Avery, Melody; Rosenlof, Karen; Davis, Sean; Hurst, Dale; Schoeberl, Mark; Diaz, Jorge Andres; Morris, Gary

2014-01-01

Balloon sonde measurements of tropical water vapor using the Cryogenic Frostpoint Hygrometer were initiated in Costa Rica in July 2005 and have continued to the present day. Over the nine years through July 2014, the Ticosonde program has launched 174 CFH payloads, representing the longest-running and most extensive single-site balloon dataset for tropical water vapor. In this presentation we present a seasonal climatology for water vapor and ozone at Costa Rica and examine the frequency of upper tropospheric supersaturation with comparisons to cloud fraction and cloud ice water content observations from the Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) on the CALIPSO mission. We then make a critical comparison of these data to water vapor measurements from the MLS instrument on board Aura in light of recently published work for other sites. Finally, we examine time series of 2-km altitude averages in the upper troposphere-lower stratosphere at Costa Rica in light of anomalies and trends seen in various large-scale indices of tropical water vapor.

40 CFR 796.1950 - Vapor pressure.

Science.gov (United States)

2010-07-01

... (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Physical and Chemical Properties § 796.1950 Vapor pressure. (a.... In addition, chemicals that are likely to be gases at ambient temperatures and which have low water... gases until the measured vapor pressure is constant, a process called “degassing.” Impurities more...

Performance of horizontal versus vertical vapor extraction wells

International Nuclear Information System (INIS)

Birdsell, K.H.; Roseberg, N.D.; Edlund, K.M.

1994-06-01

Vapor extraction wells used for site remediation of volatile organic chemicals in the vadose zone are typically vertical wells. Over the past few years, there has been an increased interest in horizontal wells for environmental remediation. Despite the interest and potential benefits of horizontal wells, there has been little study of the relative performance of horizontal and vertical vapor extraction wells. This study uses numerical simulations to investigate the relative performance of horizontal versus vertical vapor extraction wells under a variety of conditions. The most significant conclusion that can be drawn from this study is that in a homogeneous medium, a single, horizontal vapor extraction well outperforms a single, vertical vapor extraction well (with surface capping) only for long, linear plumes. Guidelines are presented regarding the use of horizontal wells

Dynamics of trivalent rare earth molecular vapor lasers

International Nuclear Information System (INIS)

Krupke, W.F.

1976-01-01

Radiative transition probabilities in neodymium bearing vapors are reviewed and calculations are extended to visible laser transitions in terbium bearing vapor. Nonradiative relaxation processes in the pure and complexed halides are treated in greater detail. While precise, quantitative relaxation probabilities cannot be calculated on the basis of information presently available, plausibility arguments can be established which indicate the order of magnitude of relevant nonradiative decay probabilities. Reference to solid and liquid state nonradiative relaxation data for rare earth ions is reviewed to support the plausibility arguments for the vapor state. Having established the likelihood of high fluorescence yields in the vapor phase, various methods of laser pumping are discussed: optical pumping via parity allowed 4f-5d transitions; optical pumping via charge transfer bands of the vapor complex; and direct electron beam pumping

Metrology at the nano scale

International Nuclear Information System (INIS)

Sheridan, B.; Cumpson, P.; Bailey, M.

2006-01-01

Progress in nano technology relies on ever more accurate measurements of quantities such as distance, force and current industry has long depended on accurate measurement. In the 19th century, for example, the performance of steam engines was seriously limited by inaccurately made components, a situation that was transformed by Henry Maudsley's screw micrometer calliper. And early in the 20th century, the development of telegraphy relied on improved standards of electrical resistance. Before this, each country had its own standards and cross border communication was difficult. The same is true today of nano technology if it is to be fully exploited by industry. Principles of measurement that work well at the macroscopic level often become completely unworkable at the nano metre scale - about 100 nm and below. Imaging, for example, is not possible on this scale using optical microscopes, and it is virtually impossible to weigh a nano metre-scale object with any accuracy. In addition to needing more accurate measurements, nano technology also often requires a greater variety of measurements than conventional technology. For example, standard techniques used to make microchips generally need accurate length measurements, but the manufacture of electronics at the molecular scale requires magnetic, electrical, mechanical and chemical measurements as well. (U.K.)

Pose measurement method with six parameters for microassembly based on an optical micrometer

Science.gov (United States)

Ye, Xin; Wang, Qiang; Zhang, Zhi-jing; Sun, Yuan; Zhang, Xiao-feng

2009-07-01

This paper presents a new pose measurement method of microminiature parts that is capable of transforming one dimension (1D) contour size obtained by optical micrometer to three dimension (3D) data with six parameters for microassembly. Pose measurement is one of the most important processes for microminiature parts' alignment and insertion in microassembly. During the past few years, researchers have developed their microassembly systems focusing on visual identification to obtain two or three dimension data with no more than three parameters. Scanning electronic microscope (SEM), optical microscope, and stereomicroscope are applied in their systems. However, as structures of microminiature parts become increasingly complex, six parameters to represent their position and orientation are specifically needed. Firstly, The pose measurement model is established based on the introduction of measuring objects and measuring principle of optical micrometer. The measuring objects are microminiature parts with complex 3D structure. Two groups of two dimension (2D) data are gathered at two different measurement positions. Then part pose with 6 parameters is calculated, including 3 position parameters of feature point of the part and 3 orientation parameters of the part axis. Secondly, pose measurement process for a small shaft, vertical orientation determination, and position parameters obtaining are presented. 2D data is gathered by scanning the generatrix of the part, and valid data is extracted and saved in arrays. A vertical orientation criterion is proposed to determine whether the part is parallel to the Z-axis of the coordinate. If not, 2D data will be fixed into a linear equation using least square algorithm. Then orientation parameters are calculated. Center of Part End (CPE) is selected as feature point of the part, and its position parameters are extracted form two group of 2D data. Finally, a fast pose measurement device is developed and representative

Control of sodium vapor transport in annuli

International Nuclear Information System (INIS)

Meadows, G.E.; Bohringer, A.P.

1983-11-01

The method used to control sodium vapor transport in the annuli of various components at the Fast Flux Test Facility (FFTF) is a downward purge of the annuli with high purity argon. The purge rates for the FFTF were selected by calculating the gas velocity required to overcome thermal convection transport in the annuli. To evaluate the effectiveness of the gas purge, laboratory apparatus was fabricated which simulated selected annuli in the FFTF In-Vessel Handling Machine (IVHM) and the Instrument Tree (IT) annuli. Tests were conducted at temperatures similar to FFTF conditions. Gas purge rates ranged from zero to 130% of FFTF flow rates. Test results show the effectiveness of a high purity gas purge in decreasing the accumulation of sodium vapor deposits in an annulus. The presence of water vapor and oxygen in the purge gas increased the sodium deposition rate by a factor of three over other tests usig high purity argon. The presence of a vapor control collar used in the IT annulus was shown to be beneficial for controlling vapor transport into the upper region of the annulus

Vapor pressure and thermodynamics of beryllium carbide

International Nuclear Information System (INIS)

Rinehart, G.H.; Behrens, R.G.

1980-01-01

The vapor pressure of beryllium carbide has been measured over the temperature range 1388 to 1763 K using Knudsen-effusion mass spectrometry. Vaporization occurs incongruently according to the reaction Be 2 C(s) = 2Be(g) + C(s). The equilibrium vapor pressure above the mixture of Be 2 C and C over the experimental temperature range is (R/J K -1 mol -1 )ln(p/Pa) = -(3.610 +- 0.009) x 10 5 (K/T) + (221.43 +- 1.06). The third-law enthalpy change for the above reaction obtained from the present vapor pressures is ΔH 0 (298.15 K) = (740.5 +- 0.1) kJ mol -1 . The corresponding second-law result is ΔH 0 (298.15 K) = (732.0 +- 1.8) kJ mol -1 . The enthalpy of formation for Be 2 C(s) calculated from the present third-law vaporization enthalpy and the enthalpy of formation of Be(g) is ΔH 0 sub(f)(298.15 K) = -(92.5 +- 15.7) kJ mol -1 . (author)

Vapor-transport of tungsten and its geologic application

Energy Technology Data Exchange (ETDEWEB)

Shibue, Y [Hyogo Univ. of Teacher Education, Hyogo (Japan)

1988-11-10

The volatility of tungsten in a hydrous system at elevated temperatures and pressures was examined, and a tentative model for the enrichment of tungsten in hydrothermal solutions for the deposits related to granitic activities was proposed. To produce vapor-saturated solution, 17 or 15ml of 20wt% NaCl solution was introduced into an autoclave. Ca(OH){sub 2} for tungsten and H{sub 2}WO{sub 4} for base metals were used as vapor-captures, and run products were identified by X-ray powder diffractometry. The results suggested that the ratio of tungsten to base metals was higher in a vapor phase than in a liquid phase, and more enrichment of tungsten in the vapor phase occurred at higher temperature and pressure under the coexistence of the vapor and liquid phase. The tentative model emphasizing the vapor-transport of tungsten could explain the presence of tungsten deposits without large mineralization of base metals. Geological schematic model for the generation of the hydrothermal solution enriched in tungsten compared with base metals was illustrated based on above mentioned results. 21 refs., 3 figs.

Evaporation of Liquid Droplet in Nano and Micro Scales from Statistical Rate Theory.

Science.gov (United States)

Duan, Fei; He, Bin; Wei, Tao

2015-04-01

The statistical rate theory (SRT) is applied to predict the average evaporation flux of liquid droplet after the approach is validated in the sessile droplet experiments of the water and heavy water. The steady-state experiments show a temperature discontinuity at the evaporating interface. The average evaporation flux is evaluated by individually changing the measurement at a liquid-vapor interface, including the interfacial liquid temperature, the interfacial vapor temperature, the vapor-phase pressure, and the droplet size. The parameter study shows that a higher temperature jump would reduce the average evaporation flux. The average evaporation flux can significantly be influenced by the interfacial liquid temperature and the vapor-phase pressure. The variation can switch the evaporation into condensation. The evaporation flux is found to remain relative constant if the droplet is larger than a micro scale, while the smaller diameters in nano scale can produce a much higher evaporation flux. In addition, a smaller diameter of droplets with the same liquid volume has a larger surface area. It is suggested that the evaporation rate increases dramatically as the droplet shrinks into nano size.

Effect of vapor-phase oxygen on chemical vapor deposition growth of graphene

Science.gov (United States)

Terasawa, Tomo-o.; Saiki, Koichiro

2015-03-01

To obtain a large-area single-crystal graphene, chemical vapor deposition (CVD) growth on Cu is considered the most promising. Recently, the surface oxygen on Cu has been found to suppress the nucleation of graphene. However, the effect of oxygen in the vapor phase was not elucidated sufficiently. Here, we investigate the effect of O2 partial pressure (PO2) on the CVD growth of graphene using radiation-mode optical microscopy. The nucleation density of graphene decreases monotonically with PO2, while its growth rate reaches a maximum at a certain pressure. Our results indicate that PO2 is an important parameter to optimize in the CVD growth of graphene.

Growth of GaN layers using Ga2O vapor obtained from Ga and H2O vapor

International Nuclear Information System (INIS)

Sumi, Tomoaki; Taniyama, Yuuki; Takatsu, Hiroaki; Juta, Masami; Kitamoto, Akira; Imade, Mamoru; Yoshimura, Masashi; Mori, Yusuke; Isemura, Masashi

2015-01-01

In this study, we performed growth of GaN layers using Ga 2 O vapor synthesized from Ga and H 2 O vapor. In this process, we employed H 2 O vapor instead of HCl gas in hydride vapor phase epitaxy (HVPE) to synthesize Ga source gas. In the synthesis reaction of Ga 2 O, a Ga 2 O 3 whisker formed and covered Ga, which impeded the synthesis reaction of Ga 2 O. The formation of the Ga 2 O 3 whisker was suppressed in H 2 ambient at high temperatures. Then, we adopted this process to supply a group III precursor and obtained an epitaxial layer. X-ray diffraction (XRD) measurement revealed that the epitaxial layer was single-crystalline GaN. Growth rate increased linearly with Ga 2 O partial pressure and reached 104 µm/h. (author)

GPS Water Vapor Tomography Based on Accurate Estimations of the GPS Tropospheric Parameters

Science.gov (United States)

Champollion, C.; Masson, F.; Bock, O.; Bouin, M.; Walpersdorf, A.; Doerflinger, E.; van Baelen, J.; Brenot, H.

2003-12-01

The Global Positioning System (GPS) is now a common technique for the retrieval of zenithal integrated water vapor (IWV). Further applications in meteorology need also slant integrated water vapor (SIWV) which allow to precisely define the high variability of tropospheric water vapor at different temporal and spatial scales. Only precise estimations of IWV and horizontal gradients allow the estimation of accurate SIWV. We present studies developed to improve the estimation of tropospheric water vapor from GPS data. Results are obtained from several field experiments (MAP, ESCOMPTE, OHM-CV, IHOP, .). First IWV are estimated using different GPS processing strategies and results are compared to radiosondes. The role of the reference frame and the a priori constraints on the coordinates of the fiducial and local stations is generally underestimated. It seems to be of first order in the estimation of the IWV. Second we validate the estimated horizontal gradients comparing zenith delay gradients and single site gradients. IWV, gradients and post-fit residuals are used to construct slant integrated water delays. Validation of the SIWV is under progress comparing GPS SIWV, Lidar measurements and high resolution meteorological models (Meso-NH). A careful analysis of the post-fit residuals is needed to separate tropospheric signal from multipaths. The slant tropospheric delays are used to study the 3D heterogeneity of the troposphere. We develop a tomographic software to model the three-dimensional distribution of the tropospheric water vapor from GPS data. The software is applied to the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers operated in southern France. Three inversions have been successfully compared to three successive radiosonde launches. Good resolution is obtained up to heights of 3000 m.

The separation of hydrocarbons from waste vapor streams

International Nuclear Information System (INIS)

Behling, R.D.; Ohlrogge, K.; Peinemann, K.V.; Kyburz, E.

1989-01-01

Hydrocarbon vapors generated from industrial processes dispersed into air are contributing factors for the creation of photochemical smog. The separation of hydrocarbon vapor by means of membranes is in case of some applications a technically simple and economic process. A membrane vapor separation process with a following treatment of the retentate by catalytic incineration is introduced in this paper

Separation of aromatics by vapor permeation through solvent swollen membrane

Energy Technology Data Exchange (ETDEWEB)

Ito, A.; Adachi, K.; Feng, Y. [Niigata University, Niigata (Japan)

1995-12-20

A vapor permeation process for aromatics separation from a hydrocarbon mixture was studied by means of the simultaneous permeation of dimethylsulfoxide vapor as an agent for membrane swelling and preferential permeation of aromatics. The separation performance of the process was demonstrated by a polyvinylalcohol membrane for mixed vapors of benzene/cyclohexane, xylene/octane and a model gasoline. The aromatic vapors preferentially permeated from these mixed vapor feeds. The separation factor was over 10. The separation mechanism of the process mainly depends on the relative salability of the vapors between aromatics and other hydrocarbons in dimethylsulfoxide. 14 refs., 9 figs., 1 tab.

Molecular dynamics study of the vaporization of an ionic drop.

Science.gov (United States)

Galamba, N

2010-09-28

The melting of a microcrystal in vacuum and subsequent vaporization of a drop of NaCl were studied through molecular dynamics simulations with the Born-Mayer-Huggins-Tosi-Fumi rigid-ion effective potential. The vaporization was studied for a single isochor at increasing temperatures until the drop completely vaporized, and gaseous NaCl formed. Examination of the vapor composition shows that the vapor of the ionic drop and gaseous NaCl are composed of neutral species, the most abundant of which, ranging from simple NaCl monomers (ion pairs) to nonlinear polymers, (Na(n)Cl(n))(n=2-4). The enthalpies of sublimation, vaporization, and dissociation of the different vapor species are found to be in reasonable agreement with available experimental data. The decrease of the enthalpy of vaporization of the vapor species, with the radius of the drop decrease, accounts for a larger fraction of trimers and tetramers than that inferred from experiments. Further, the rhombic dimer is significantly more abundant than its linear isomer although the latter increases with the temperature. The present results suggest that both trimers and linear dimers may be important to explain the vapor pressure of molten NaCl at temperatures above 1500 K.

Vapor condensation device

International Nuclear Information System (INIS)

Sakurai, Manabu; Hirayama, Fumio; Kurosawa, Setsumi; Yoshikawa, Jun; Hosaka, Seiichi.

1992-01-01

The present invention enables to separate and remove 14 C as CO 3 - ions without condensation in a vapor condensation can of a nuclear facility. That is, the vapor condensation device of the nuclear facility comprises (1) a spray pipe for spraying an acidic aqueous solution to the evaporation surface of an evaporation section, (2) a spray pump for sending the acidic aqueous solution to the spray pipe, (3) a tank for storing the acidic aqueous solution, (4) a pH sensor for detecting pH of the evaporation section, (5) a pH control section for controlling the spray pump, depending on the result of the detection of the pH sensor. With such a constitution, the pH of liquid wastes on the vaporization surface is controlled to 7 by spraying an aqueous solution of dilute sulfuric acid to the evaporation surface, thereby enabling to increase the transfer rate of 14 C to condensates to 60 to 70%. If 14 C is separated and removed as a CO 2 gas from the evaporation surface, the pH of the liquid wastes returns to the alkaline range of 9 to 10 and the liquid wastes are returned to a heating section. The amount of spraying the aqueous solution of dilute sulfuric acid can be controlled till the pH is reduced to 5. (I.S.)

Optimization of Charcoal Production Process from Woody Biomass Waste: Effect of Ni-Containing Catalysts on Pyrolysis Vapors

Directory of Open Access Journals (Sweden)

Jon Solar

2018-05-01

Full Text Available Woody biomass waste (Pinus radiata coming from forestry activities has been pyrolyzed with the aim of obtaining charcoal and, at the same time, a hydrogen-rich gas fraction. The pyrolysis has been carried out in a laboratory scale continuous screw reactor, where carbonization takes place, connected to a vapor treatment reactor, at which the carbonization vapors are thermo-catalytically treated. Different peak temperatures have been studied in the carbonization process (500–900 °C, while the presence of different Ni-containing catalysts in the vapor treatment has been analyzed. Low temperature pyrolysis produces high liquid and solid yields, however, increasing the temperature progressively up to 900 °C drastically increases gas yield. The amount of nickel affects the vapors treatment phase, enhancing even further the production of interesting products such as hydrogen and reducing the generated liquids to very low yields. The gases obtained at very high temperatures (700–900 °C in the presence of Ni-containing catalysts are rich in H2 and CO, which makes them valuable for energy production, as hydrogen source, producer gas or reducing agent.

Horizontal Variability of Water and Its Relationship to Cloud Fraction near the Tropical Tropopause: Using Aircraft Observations of Water Vapor to Improve the Representation of Grid-scale Cloud Formation in GEOS-5

Science.gov (United States)

Selkirk, Henry B.; Molod, Andrea M.

2014-01-01

Large-scale models such as GEOS-5 typically calculate grid-scale fractional cloudiness through a PDF parameterization of the sub-gridscale distribution of specific humidity. The GEOS-5 moisture routine uses a simple rectangular PDF varying in height that follows a tanh profile. While below 10 km this profile is informed by moisture information from the AIRS instrument, there is relatively little empirical basis for the profile above that level. ATTREX provides an opportunity to refine the profile using estimates of the horizontal variability of measurements of water vapor, total water and ice particles from the Global Hawk aircraft at or near the tropopause. These measurements will be compared with estimates of large-scale cloud fraction from CALIPSO and lidar retrievals from the CPL on the aircraft. We will use the variability measurements to perform studies of the sensitivity of the GEOS-5 cloud-fraction to various modifications to the PDF shape and to its vertical profile.

Headspace gas and vapor characterization summary for the 43 vapor program suspect tanks

International Nuclear Information System (INIS)

Huckaby, J.L.; Bratzel, D.R.

1995-01-01

During the time period between February 1994 and September 1995, Westinghouse Hanford Company (WHC) sampled the waste tank headspace of 43 single-shell tanks for a variety of gaseous and/or volatile and semi-volatile compounds. This report summarizes the results of analyses of those sampling activities with respect to both the Priority 1 Safety Issues and relative to the detection in the headspace of significant concentrations of target analytes relating to worker breathing space consideration as recommended by the Pacific Northwest Laboratory (PNL) Toxicology Review Panel. The information contained in the data tables was abstracted from the vapor sampling and analysis tank characterization reports. Selected results are tabulated and summarized. Sampling equipment and methods, as well as sample analyses, are briefly described. Vapor sampling of passively ventilated single-shell tanks (tanks C-105, C-106, and SX-106 were sampled and are actively ventilated) has served to highlight or confirm tank headspace conditions associated with both priority 1 safety issues and supports source term analysis associated with protecting worker health and safety from noxious vapors

Fuel conditioning facility electrorefiner cadmium vapor trap operation

International Nuclear Information System (INIS)

Vaden, D. E.

1998-01-01

Processing sodium-bonded spent nuclear fuel at the Fuel Conditioning Facility at Argonne National Laboratory-West involves an electrometallurgical process employing a molten LiCl-KCl salt covering a pool of molten cadmium. Previous research has shown that the cadmium dissolves in the salt as a gas, diffuses through the salt layer and vaporizes at the salt surface. This cadmium vapor condenses on cool surfaces, causing equipment operation and handling problems. Using a cadmium vapor trap to condense the cadmium vapors and reflux them back to the electrorefiner has mitigated equipment problems and improved electrorefiner operations

Water Vapor Remote Sensing Techniques: Radiometry and Solar Spectrometry

Science.gov (United States)

Somieski, A.; Buerki, B.; Cocard, M.; Geiger, A.; Kahle, H.-G.

The high variability of atmospheric water vapor content plays an important role in space geodesy, climatology and meteorology. Water vapor has a strong influence on transatmospheric satellite signals, the Earth's climate and thus the weather forecasting. Several remote sensing techniques have been developed for the determination of inte- grated precipitable water vapor (IPWV). The Geodesy and Geodynamics Lab (GGL) utilizes the methods of Water Vapor Radiometry and Solar Spectrometry to quantify the amount of tropospheric water vapor and its temporal variations. The Water Vapor Radiometer (WVR) measures the radiation intensity of the atmosphere in a frequency band ranging from 20 to 32 GHz. The Solar Atmospheric MOnitoring Spectrome- ter (SAMOS) of GGL is designed for high-resolution measurements of water vapor absorption lines using solar radiation. In the framework of the ESCOMPTE (ExpÊrience sur Site pour COntraindre les Mod- Éles de Pollution atmosphÊrique et de Transport d'Emissions) field campaign these instruments have been operated near Marseille in 2001. They have aquired a long time series of integrated precipitable water vapor content (IPWV). The accuracy of IPWV measured by WVR and SAMOS is 1 kg/m2. Furthermore meteorological data from radiosondes were used to calculate the IPWV in order to provide comparisons with the results of WVR and SAMOS. The methods of Water Vapor Radiometry and So- lar Spectrometry will be discussed and first preliminary results retrieved from WVR, SAMOS and radiosondes during the ESCOMPTE field campaign will be presented.

The preparation and cathodoluminescence of ZnS nanowires grown by chemical vapor deposition

International Nuclear Information System (INIS)

Huang, Meng-Wen; Cheng, Yin-Wei; Pan, Ko-Ying; Chang, Chen-Chuan; Shieu, F.S.; Shih, Han C.

2012-01-01

Highlights: ► ZnS nanowires have been achieved by thermal evaporation. ► The nanowires were 20–50 nm in diameter and up to tens of nanometers in length. ► Single-crystalline wurtzite and sphalerite ZnS phase are coexist in the nanowires. ► The ZnS nanowires showed almost identical blue luminescence at room temperature. ► ZnS nanowires may be appropriate for use in UV/blue LED phosphor materials. - Abstract: Single crystal ZnS nanowires were successfully synthesized in large quantities on Si (1 0 0) substrates by simple thermal chemical vapor deposition without using any catalyst. The morphology, composition, and crystal structure were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and cathodoluminescence (CL) spectroscopy. SEM observations show that the nanowires have diameters about 20–50 nm and lengths up to several tens of micrometers. XRD and TEM results confirmed that the nanowires exhibited both wurtzite and zinc blende structures with growth directions aligned along [0 0 0 2] and [1 1 1], respectively. The CL spectrum revealed emission bands in the UV and blue regions. The blue emissions at 449 and ∼581 nm were attributed to surface states and impurity-related defects of the nanowires, respectively. The perfect crystal structure of the nanowires indicates their potential applications in nanotechnology and in the fabrication of nanodevices.

Investigation of Pore Scale Processes That Affect Soil Vapor Extraction. Final Technical Report EMSP 70045

International Nuclear Information System (INIS)

Valocchi, Albert J.; Werth, Charles W.; Webb, Andrew W.

2004-01-01

Dense nonaqueous phase liquid (DNAPL) contamination in the vadose zone is a significant problem at Department of Energy sites. Soil vapor extraction (SVE) is commonly used to remediate DNAPLs from the vadose zone. In most cases, a period of high recovery has been followed by a sustained period of low recovery. This behavior has been attributed to multiple processes including slow interphase mass transfer, retarded vapor phase transport, and diffusion from unswept zones of low permeability. This research project used a combination of laboratory experimentation and mathematical modeling to determine how these various processes interact to limit the removal of DNAPL components in heterogeneous porous media during SVE. Our results were applied to scenarios typical of the carbon tetrachloride spill zone at the Hanford Site. Our results indicate that: (a) the initial distribution of the spilled DNAPL (i.e., the spill-zone architecture) has a major influence upon the performance of any subsequent SVE operations; (b) while the pattern of higher and lower conductivity soil zones has an important impact upon spill zone architecture, soil moisture distribution plays an even larger role when there are large quantities of co-disposed waste-water (as in the Hanford scenario); (c) depending upon soil moisture dynamics, liquid DNAPL that is trapped by surrounding water is extremely difficult to remove by SVE; (d) natural barometric pumping can remove a large amount of the initial DNAPL mass for spills occurring close to the land surface, and hence the initial spilled inventory will be over-estimated if this process is neglected

Mass spectrometric study of Nd2S3 vaporization

International Nuclear Information System (INIS)

Fenochka, B.V.

1987-01-01

The authors conduct a mass-spectrometric study of neodymium(III) sulfide vaporization. The chemical composition of the samples was stoichiometric and the samples were vaporized from tantalum effusion cells. When the vapor over Nd 2 S 3 is ionized by electrons the mass spectra shows monovalent cations of Nd, S, NdS, and NdO. The enthalpy of vaporization if Nd atoms from Nd 2 S 3 at average experimental temperatures and the standard enthalpy of reaction is shown. Also presented is the enthalpy of vaporization of NdS molecules from Nd 2 S 3 at average experimental temperatures and the standard enthalpy of reaction

The vapor pressure and vaporization enthalpy of R-(+)-menthofuran, a hepatotoxin metabolically derived from the abortifacient terpene, (R)-(+)-pulegone by correlation gas chromatography

International Nuclear Information System (INIS)

Gobble, Chase; Chickos, James S.

2016-01-01

Highlights: • The vaporization enthalpy and vapor pressure of R-(+) menthofuran is evaluated. • The normal boiling temperature is predicted and compared to experimental and predicted values. • A vapor pressure equation as a function of temperature for menthofuran is evaluated. - Abstract: The vapor pressure as a function of temperature and its vaporization enthalpy at T = 298.15 K of R-(+)-menthofuran, a substance metabolically derived from R-(+)-pulegone that is both a flavoring agent at low concentrations and a hepatotoxin at larger ones, is evaluated by correlation-gas chromatography. A vapor pressure p/Pa = (36 ± 12) has been evaluated at T = 298.15 K, and a normal boiling temperature of T_b/K = 482.4 K is predicted. A boiling temperature of T_b/K = 374.3 compares with the literature value of T_b/K = 371.2 at reduced pressure, p/kPa = 2.93. The vaporization enthalpy of (56.5 ± 3.0) kJ·mol"−"1 compares to an estimated value of (57.8 ± 2.9) kJ·mol"−"1.

Vernier Caliper and Micrometer Computer Models Using Easy Java Simulation and Its Pedagogical Design Features--Ideas for Augmenting Learning with Real Instruments

Science.gov (United States)

Wee, Loo Kang; Ning, Hwee Tiang

2014-01-01

This paper presents the customization of Easy Java Simulation models, used with actual laboratory instruments, to create active experiential learning for measurements. The laboratory instruments are the vernier caliper and the micrometer. Three computer model design ideas that complement real equipment are discussed. These ideas involve (1) a…

Vapor generation rate model for dispersed drop flow

International Nuclear Information System (INIS)

Unal, C.; Tuzla, K.; Cokmez-Tuzla, A.F.; Chen, J.C.

1991-01-01

A comparison of predictions of existing nonequilibrium post-CHF heat transfer models with the recently obtained rod bundle data has been performed. The models used the experimental conditions and wall temperatures to predict the heat flux and vapor temperatures at the location of interest. No existing model was able to reasonably predict the vapor superheat and the wall heat flux simultaneously. Most of the models, except Chen-Sundaram-Ozkaynak, failed to predict the wall heat flux, while all of the models could not predict the vapor superheat data or trends. A recently developed two-region heat transfer model, the Webb-Chen two-region model, did not give a reasonable prediction of the vapor generation rate in the far field of the CHF point. A new correlation was formulated to predict the vapor generation rate in convective dispersed droplet flow in terms of thermal-hydraulic parameters and thermodynamic properties. A comparison of predictions of the two-region heat transfer model, with the use of a presently developed correlation, with all the existing post-CHF data, including single-tube and rod bundle, showed significant improvements in predicting the vapor superheat and tube wall heat flux trends. (orig.)

Expansion of a vapor bubble and aerosols transfer

International Nuclear Information System (INIS)

Breton, J.P.; Lapicore, A.; Porrachia, A.; Natta, M.; Amblard, M.; Berthoud, G.

1979-08-01

Experimental results on the expansion and collapse of two phase vapor bubble, and on the aerosols transport outside the tank are presented. Two facilities using small source of hot water (2 cm 3 ) or bigger ones (1000 cm 3 ) were used and are described. Two models are developped to analyze the results on the bubble. They show the heat and mass transfer from the bubble to the surroundings and the following reduction in the mechanical energy delivered by the bubble, and the decrease in this reduction due to noncondensables and to scale effect. The models developed or the aerosol transfer show that most particles are likely transported from the bubble to the cover gas

Tritium-gas/water-vapor monitor. Tests and evaluation

International Nuclear Information System (INIS)

Jalbert, R.A.

1982-07-01

A tritium gas/water-vapor monitor was designed and built by the Health Physics Group at the Los Alamos National Laboratory. In its prototype configuration, the monitor took the shape of two separate instruments: a (total) tritium monitor and a water-vapor monitor. Both instruments were tested and evaluated. The tests of the (total) tritium monitor, basically an improved version of the standard flow-through ion-chamber instrument, are briefly reported here and more completely elsewhere. The tests of the water-vapor monitor indicated that the novel approach used to condense water vapor for scintillation counting has a number of serious drawbacks and that further development of the instrument is unwarranted

Influence of soil properties on vapor-phase sorption of trichloroethylene

International Nuclear Information System (INIS)

Bekele, Dawit N.; Naidu, Ravi; Chadalavada, Sreenivasulu

2016-01-01

Highlights: • Vapor intrusion is a major exposure pathway for volatile hydrocarbons. • Certainty in transport processes enhances vapor intrusion model precision. • Detailed understanding of vadose zone vapor transport processes save resources. • Vapor sorption near-steady-state conditions at sites may take months or years. • Type of clay fractions equitably affects sorption of trichloroethylene vapor. - Abstract: Current practices in health risk assessment from vapor intrusion (VI) using mathematical models are based on assumptions that the subsurface sorption equilibrium is attained. The time required for sorption to reach near-steady-state conditions at sites may take months or years to achieve. This study investigated the vapor phase attenuation of trichloroethylene (TCE) in five soils varying widely in clay and organic matter content using repacked columns. The primary indicators of TCE sorption were vapor retardation rate (R_t), the time required for the TCE vapor to pass through the soil column, and specific volume of retention (V_R), and total volume of TCE retained in soil. Results show TCE vapor retardation is mainly due to the rapid partitioning of the compound to SOM. However, the specific volume of retention of clayey soils with secondary mineral particles was higher. Linear regression analyses of the SOM and clay fraction with V_R show that a unit increase in clay fraction results in higher sorption of TCE (V_R) than the SOM. However, partitioning of TCE vapor was not consistent with the samples' surface areas but was mainly a function of the type of secondary minerals present in soils.

Influence of soil properties on vapor-phase sorption of trichloroethylene

Energy Technology Data Exchange (ETDEWEB)

Bekele, Dawit N. [Global Center for Environmental Remediation, University of Newcastle, Callaghan, NSW 2308 (Australia); CRC for Contamination Assessment & Remediation of the Environment, Building X (Environmental Sciences Building), University of South Australia, Mawson Lakes, SA 5095 (Australia); Naidu, Ravi, E-mail: Ravi.Naidu@newcastle.edu.au [Global Center for Environmental Remediation, University of Newcastle, Callaghan, NSW 2308 (Australia); CRC for Contamination Assessment & Remediation of the Environment, Building X (Environmental Sciences Building), University of South Australia, Mawson Lakes, SA 5095 (Australia); Chadalavada, Sreenivasulu [Global Center for Environmental Remediation, University of Newcastle, Callaghan, NSW 2308 (Australia); CRC for Contamination Assessment & Remediation of the Environment, Building X (Environmental Sciences Building), University of South Australia, Mawson Lakes, SA 5095 (Australia)

2016-04-05

Highlights: • Vapor intrusion is a major exposure pathway for volatile hydrocarbons. • Certainty in transport processes enhances vapor intrusion model precision. • Detailed understanding of vadose zone vapor transport processes save resources. • Vapor sorption near-steady-state conditions at sites may take months or years. • Type of clay fractions equitably affects sorption of trichloroethylene vapor. - Abstract: Current practices in health risk assessment from vapor intrusion (VI) using mathematical models are based on assumptions that the subsurface sorption equilibrium is attained. The time required for sorption to reach near-steady-state conditions at sites may take months or years to achieve. This study investigated the vapor phase attenuation of trichloroethylene (TCE) in five soils varying widely in clay and organic matter content using repacked columns. The primary indicators of TCE sorption were vapor retardation rate (R{sub t}), the time required for the TCE vapor to pass through the soil column, and specific volume of retention (V{sub R}), and total volume of TCE retained in soil. Results show TCE vapor retardation is mainly due to the rapid partitioning of the compound to SOM. However, the specific volume of retention of clayey soils with secondary mineral particles was higher. Linear regression analyses of the SOM and clay fraction with V{sub R} show that a unit increase in clay fraction results in higher sorption of TCE (V{sub R}) than the SOM. However, partitioning of TCE vapor was not consistent with the samples' surface areas but was mainly a function of the type of secondary minerals present in soils.

Fabrication and performance evaluation of a high temperature co-fired ceramic vaporizing liquid microthruster

International Nuclear Information System (INIS)

Cheah, Kean How; Low, Kay-Soon

2015-01-01

This paper presents the study of a microelectromechanical system (MEMS)-scaled microthruster using ceramic as the structural material. A vaporizing liquid microthruster (VLM) has been fabricated using the high temperature co-fired ceramic (HTCC) technology. The developed microthruster consists of five components, i.e. inlet, injector, vaporizing chamber, micronozzle and microheater, all integrated in a chip with a dimension of 30 mm × 26 mm × 8 mm. In the dry test, the newly developed microheater which is deposited on zirconia substrate consumes 21% less electrical power than those deposited on silicon substrate to achieve a temperature of 100 °C. Heating temperature as high as 409.1 °C can be achieved using just 5 W of electrical power. For simplicity and safety, a functional test of the VLM with water as propellant has been conducted in the laboratory. Full vaporization of water propellant feeding at different flow rates has been successfully demonstrated. A maximum thrust of 633.5 µN at 1 µl s −1 propellant consumption rate was measured using a torsional thrust stand. (paper)

Uptake of mercury vapor by wheat. An assimilation model

International Nuclear Information System (INIS)

Browne, C.L.; Fang, S.C.

1978-01-01

Using a whole-plant chamber and 203 Hg-labeled mercury, a quantitative study was made of the effect of environmental parameters on the uptake, by wheat (Triticum aestivum), of metallic mercury vapor, an atmospheric pollutant. Factors were examined in relation to their influence on components of the gas-assimilation model, U(Hg) = (C/sub A' -- C/sub L')/(r/sub L.Hg/ + r/sub M.Hg/) where U(Hg) is the rate of mercury uptake per unit leaf surface, C/sub A'/ is the ambient mercury vapor concentration, C/sub L'/ is the mercury concentration at immobilization sites within the plant (assumed to be zero), r/sub L.Hg/ is the total leaf resistance to mercury vapor exchange, and r/sub M.Hg/ is a residual term to account for unexplained physical and biochemical resistances to mercury vapor uptake. Essentially all mercury vapor uptake was confined to the leaves. r/sub L.Hg/ was particularly influenced by illumination (0 to 12.8 klux), but unaffected by ambient temperature (17 to 33 0 C) and mercury vapor concentration (0 to 40 μg m -3 ). The principal limitation to mercury vapor uptake was r/sub M.Hg/, which was linearly related to leaf temperature, but unaffected by mercury vapor concentration and illumination, except for apparent high values in darkness. Knowing C/sub A'/ and estimating r/sub L.Hg/ and r/sub M.Hg/ from experimental data, mercury vapor uptake by wheat in light was accurately predicted for several durations of exposure using the above model

Sound Propagation in Gas-Vapor-Droplet Suspensions with Evaporation and Nonlinear Particle Relaxation

Science.gov (United States)

Kandula, Max

2012-01-01

The Sound attenuation and dispersion in saturated gas-vapor-droplet mixture in the presence of evaporation has been investigated theoretically. The theory is based on an extension of the work of Davidson to accommodate the effects of nonlinear particle relaxation processes of mass, momentum and energy transfer on sound attenuation and dispersion. The results indicate the existence of a spectral broadening effect in the attenuation coefficient (scaled with respect to the peak value) with a decrease in droplet mass concentration. It is further shown that for large values of the droplet concentration the scaled attenuation coefficient is characterized by a universal spectrum independent of droplet mass concentration.

Rapid growth of diamond-like-carbon films by copper vapor laser ablation

International Nuclear Information System (INIS)

McLean, W.; Warner, B.E.; Havstad, M.A.

1995-04-01

Visible light from a copper vapor laser (CVL) operating with 510 and 578 nm radiation (intensity ratio approximately 2:1), an average power of 100 W, a pulse duration of 50 ns, and a repetition frequency of 4.4 kHz has been shown to produce high quality diamond-like-carbon (DLC) films at fluences between 2x10 8 and 5x10 10 W/cm 2 . Maximum deposition rates of 2000 μm·cm 2 /h were obtained at 5x10 8 W/cm 2 . DLC films with hardness values of approximately 60 GPa were characterized by a variety of techniques to confirm DLC character, hydrogen content, and surface morphology. The presence of C 2 in the vapor plume was confirmed by the presence of the C 2 Swan bands in emission spectra obtained during the process. Economic implications of process scale-up to industrially meaningful component sizes are presented

Volatilization of multicomponent mixtures in soil vapor extraction applications

International Nuclear Information System (INIS)

Bass, D.H.

1995-01-01

In soil vapor extraction (SVE) applications involving multicomponent mixtures, prediction of mass removal by volatilization as a function remediation extent is required to estimate remediation time and to size offgas treatment equipment. SVE is a commonly used remediation technology which volatilizes and enhances aerobic biodegradation of contamination adsorbed to vadose zone soils. SVE is often applied at sites contaminated with petroleum products, which are usually mixtures of many different compounds with vapor pressures spanning several orders of magnitude. The most volatile components are removed first, so the vapor pressure of the remaining contaminant continually decreases over the course of the remediation. A method for assessing how vapor pressure, and hence the rate of volatilization, of a multicomponent mixture changes over the course of a vapor extraction remedy has been developed. Each component is listed, alone, with its mass fraction in the mixture, in decreasing order of pure component vapor pressure (where component analyses are unavailable, model compounds can be used), For most petroleum distillates, the vapor pressure for each component plotted against the cumulative mass fraction of the component in the mixture on semilog coordinates will produce a straight line with a high correlation coefficient. This regression can be integrated to produce an expression for vapor pressure of the overall mixture as a function of extent or remediation

HWCVD of polymers: Commercialization and scale-up

International Nuclear Information System (INIS)

Pryce Lewis, Hilton G.; Bansal, Neeta P.; White, Aleksandr J.; Handy, Erik S.

2009-01-01

GVD Corporation specializes in process development and equipment design for the production of ultra-thin polymer coatings using hot wire chemical vapor deposition (HWCVD, also known as initiated chemical vapor deposition, iCVD). HWCVD allows many coating compositions to be produced, including fluorocarbon and silicone polymers, copolymers, and vinyl hydrocarbon polymers. It is especially valuable for creating ultra-thin layers of insoluble, infusible polymers which are hard to process by conventional means, such as polytetrafluoroethylene (PTFE, Teflon. HWCVD PTFE coatings are chemically robust, comprised of essentially 100% CF 2 , resistant to solvents, conformal to complex surface geometry, and have excellent adhesion to a wide range of substrates. Since the part to be coated remains at room temperature, fragile materials like plastics and fabrics can be coated with ease. GVD has focused on scale-up of the process equipment and has developed several standard coating systems, which will be discussed in this paper. These include laboratory-scale batch coating systems, a medium sized production batch coating system, a large scale custom batch coater, and a pilot scale roll-to-roll web coater. All of GVD's systems are complete with fully automated, computer based control systems and include options for effluent monitors and an exhaust scrubber.

Detección de micrometástasis de carcinoma de colon en ganglios linfáticos

Directory of Open Access Journals (Sweden)

A. Roma

2003-10-01

Full Text Available En el carcinoma colorrectal la diseminación a los ganglios linfáticos es un factor pronóstico reconocido. La presencia de ganglios linfáticos con micrometástasis en muchos casos no puede ser detectada por técnicas rutinarias. Se estudiaron prospectivamente 162 ganglios linfáticos de 30 pacientes con carcinoma de colon, los cuales según los resultados de las técnicas rutinarias fueron clasificados como Dukes A (2, Dukes B (19 y Dukes C (9. Un paciente con enfermedad colónica benigna se uso como control negativo. Todos los ganglios se seccionaron en mitades, una de las cuales se almacenó en nitrógeno líquido para su ulterior estudio por técnicas de biología molecular, mediante la expresión del antígeno carcinoembrionario (CEA. La otra mitad fue fijada en formaldehído e incluida en parafina para su estudio anatomopatológico e inmunohistoquímico. Del total de los casos se detectó un aumento del 50% de la sensibilidad en la detección de micrometástasis mediante la reacción en cadena de la polimerasa con transcriptasa reversa (RT-PCR para los Dukes A-B y se detectó la expresión de dicho antígeno en el total de los casos Dukes C. Estos resultados evidencian una mayor sensibilidad en la detección de micrometástasis utilizando RT-PCR en comparación con las técnicas rutinarias, incluyendo la inmunohistoquímica.Dissemination of lymph nodes is a known prognostic factor in colorectal carcinoma. Micrometastases in lymph nodes can be missed when studied by routine techniques. We analyzed 162 lymph nodes from 30 patients with colonic carcinoma and using routine techniques, they were classified as follows: two Dukes A; nineteen Dukes B; and nine Dukes C. A patient with benign colon disease served as negative control. Lymph nodes were all sectioned in halves, with one of the halves stored in liquid nitrogen for molecular biology examination by carcinoembryonic antigen expression. The other formalin-fixed and paraffin embedded

Vapor Pressures of Several Commercially Used Alkanolamines

NARCIS (Netherlands)

Klepacova, Katarina; Huttenhuis, Patrick J. G.; Derks, Peter W. J.; Versteeg, Geert F.; Klepáčová, Katarína

For the design of acid gas treating processes, vapor-liquid equilibrium (VLE) data must be available of the solvents to be applied. In this study the vapor pressures of seven frequently industrially used alkanolamines (diethanolamine, N-methylethanolamine, N,N-dimethylethanolamine,

Recommended vapor pressures for thiophene, sulfolane, and dimethyl sulfoxide

Czech Academy of Sciences Publication Activity Database

Fulem, Michal; Růžička, K.; Růžička, M.

2011-01-01

Roč. 303, č. 2 (2011), s. 205-216 ISSN 0378-3812 Institutional research plan: CEZ:AV0Z10100521 Keywords : thiophene sulfolane * dimethyl sulfoxide * vapor pressure * heat capacity * vaporization enthalpy * recommended vapor pressure equation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.139, year: 2011

An evaluation of vapor extraction of vadose zone contamination

International Nuclear Information System (INIS)

Crotwell, A.T.; Waehner, M.J.; MacInnis, J.M.; Travis, C.C.; Lyon, B.F.

1992-05-01

An in-depth analysis of vapor extraction for remediation of soils contaminated with volatile organic compounds (VOCS) was conducted at 13 sites. The effectiveness of vapor extraction systems (VES) was evaluated on the basis of soil concentrations of VOCs and soil-gas concentrations of VOC's. The range of effectiveness was found to be 64%--99% effective in removing organic contaminants from soil. At nine of the 13 sites studied in this report, vapor extraction was found to be effective in reducing VOC cooncentrations by at least 90%. At the remaining four sites studied, vapor extraction was found to reduce VOC concentrations by less than 90%. Vapor extraction is ongoing at two of these sites. At a third, the ineffectiveness of the vapor extraction is attributed to the presence of ''hot spots'' of contamination. At the fourth site, where performance was found to be relatively poor, the presence of geological tar deposits at the site is thought to be a major factor in the ineffectiveness

Room-Temperature Single-Photon Emission from Micrometer-Long Air-Suspended Carbon Nanotubes

Science.gov (United States)

Ishii, A.; Uda, T.; Kato, Y. K.

2017-11-01

Statistics of photons emitted by mobile excitons in individual carbon nanotubes are investigated. Photoluminescence spectroscopy is used to identify the chiralities and suspended lengths of air-suspended nanotubes, and photon-correlation measurements are performed at room temperature on telecommunication-wavelength nanotube emission with a Hanbury-Brown-Twiss setup. We obtain zero-delay second-order correlation g(2 )(0 ) less than 0.5, indicating single-photon generation. Excitation power dependence of the photon antibunching characteristics is examined for nanotubes with various chiralities and suspended lengths, where we find that the minimum value of g(2 )(0 ) is obtained at the lowest power. The influence of exciton diffusion and end quenching is studied by Monte Carlo simulations, and we derive an analytical expression for the minimum value of g(2 )(0 ). Our results indicate that mobile excitons in micrometer-long nanotubes can in principle produce high-purity single photons, leading to new design strategies for quantum photon sources.

Probing dielectric ceramics surface at sub-micrometer scale

Energy Technology Data Exchange (ETDEWEB)

Fiorenza, Patrick; Lo Nigro, Raffaella; Raineri, Vito [Istituto per la Microelettronica e Microsistemi, Consiglio Nazionale delle Ricerche, Stradale Primosole 50, 95121 Catania (Italy); Schmidt, Rainer; Sinclair, Derek C, E-mail: patrick.fiorenza@imm.cnr.it [Department of Engineering Materials, Sir Robert Hadfield Building, University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

2010-02-15

Scanning probe microscopy (SPM) with conductive tips has been used to image the dielectric properties of ceramics with giant permittivity. In particular, measurements in impedance mode of local resistivity allowed to image the permittivity map on polycrystalline materials. Such imaging provides correlation between the dielectric properties and the sample structure, in particular focusing on defects inside the single grains. Great attention has been devoted to the possible artefacts due to surface imperfections, such as huge roughness and/or contamination. A reliable surface investigation has been obtained after the definition of both the physical and geometrical criteria to avoid the artefacts due to both the surface or anomalous tip-sample contact area variation (for instance, in grain boundaries, holes and cracks in the ceramic pills). In particular, the power spectral density (PSD) allows to get access to the different periodic components of the surface roughness. The PSD demonstrated to be a sensitive tool to check the surface conditions after the polishing procedures aimed to the progressive decreasing of surface roughness, in order to reach the SPM limits and to avoid artefacts inducing wrong data interpretation.

Risk assessment of metal vapor arcing

Science.gov (United States)

Hill, Monika C. (Inventor); Leidecker, Henning W. (Inventor)

2009-01-01

A method for assessing metal vapor arcing risk for a component is provided. The method comprises acquiring a current variable value associated with an operation of the component; comparing the current variable value with a threshold value for the variable; evaluating compared variable data to determine the metal vapor arcing risk in the component; and generating a risk assessment status for the component.

Transient local heat fluxes during the entire vapor bubble life time

Energy Technology Data Exchange (ETDEWEB)

Stephan, P.; Fuchs, T; Wagner, E.; Schweizer, N. [Technische Universitaet Darmstadt (Germany). Technical Thermodynamics], e-mail: pstephan@ttd.tu-darmstadt.de

2009-07-01

Recent experimental and numerical investigations of the nucleate boiling heat transfer process at a single active nucleation site are presented and used for an evaluation of the local heat fluxes during the entire life time of a vapor bubble from its nucleation to the rise through the thermal boundary layer. In a special boiling cell, vapor bubbles are generated at a single nucleation site on a 20 {mu}m thin stainless steel heating foil. An infrared camera captures the temperature distribution at the wall with high temporal and spatial resolution. The bubble shape is recorded with a high-speed camera. Measurements were conducted with the pure fluids FC-84 and FC-3284 and with its binary mixtures. For pure fluids, up to 50-60% of the latent heat flows through the three-phase-contact line region. For mixtures, this ratio is clearly reduced. These observations are in agreement with the numerical model of the author's group. The fully transient model contains a multi scale approach ranging from the nanometer to the millimeter scale for the detailed description of the relevant local and global phenomena. It describes the transient heat and fluid flow during the entire periodic cycle of a growing, detaching and rising bubble including the waiting time between two successive bubbles from a single nucleation site. The detailed analysis of the computed transient temperature profiles in wall and fluid give accurate information about the heat supply, temporal energy storage and local evaporation rates. (author)

Transient local heat fluxes during the entire vapor bubble life time

International Nuclear Information System (INIS)

Stephan, P.; Fuchs, T; Wagner, E.; Schweizer, N.

2009-01-01

Recent experimental and numerical investigations of the nucleate boiling heat transfer process at a single active nucleation site are presented and used for an evaluation of the local heat fluxes during the entire life time of a vapor bubble from its nucleation to the rise through the thermal boundary layer. In a special boiling cell, vapor bubbles are generated at a single nucleation site on a 20 μm thin stainless steel heating foil. An infrared camera captures the temperature distribution at the wall with high temporal and spatial resolution. The bubble shape is recorded with a high-speed camera. Measurements were conducted with the pure fluids FC-84 and FC-3284 and with its binary mixtures. For pure fluids, up to 50-60% of the latent heat flows through the three-phase-contact line region. For mixtures, this ratio is clearly reduced. These observations are in agreement with the numerical model of the author's group. The fully transient model contains a multi scale approach ranging from the nanometer to the millimeter scale for the detailed description of the relevant local and global phenomena. It describes the transient heat and fluid flow during the entire periodic cycle of a growing, detaching and rising bubble including the waiting time between two successive bubbles from a single nucleation site. The detailed analysis of the computed transient temperature profiles in wall and fluid give accurate information about the heat supply, temporal energy storage and local evaporation rates. (author)

Analysis of organic vapors with laser induced breakdown spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Nozari, Hadi; Tavassoli, Seyed Hassan [Laser and Plasma Research Institute, Shahid Beheshti University, G. C, 1983963113 Evin, Tehran (Iran, Islamic Republic of); Rezaei, Fatemeh, E-mail: fatemehrezaei@kntu.ac.ir [Department of Physics, K. N. Toosi University of Technology, 15875-4416 Shariati, Tehran (Iran, Islamic Republic of)

2015-09-15

In this paper, laser induced breakdown spectroscopy (LIBS) is utilized in the study of acetone, ethanol, methanol, cyclohexane, and nonane vapors. Carbon, hydrogen, oxygen, and nitrogen atomic emission spectra have been recorded following laser-induced breakdown of the organic vapors that are mixed with air inside a quartz chamber at atmospheric pressure. The plasma is generated with focused, Q-switched Nd:YAG radiation at the wavelength of 1064 nm. The effects of ignition and vapor pressure are discussed in view of the appearance of the emission spectra. The recorded spectra are proportional to the vapor pressure in air. The hydrogen and oxygen contributions diminish gradually with consecutive laser-plasma events without gas flow. The results show that LIBS can be used to characterize organic vapor.

Analysis of organic vapors with laser induced breakdown spectroscopy

International Nuclear Information System (INIS)

Nozari, Hadi; Tavassoli, Seyed Hassan; Rezaei, Fatemeh

2015-01-01

In this paper, laser induced breakdown spectroscopy (LIBS) is utilized in the study of acetone, ethanol, methanol, cyclohexane, and nonane vapors. Carbon, hydrogen, oxygen, and nitrogen atomic emission spectra have been recorded following laser-induced breakdown of the organic vapors that are mixed with air inside a quartz chamber at atmospheric pressure. The plasma is generated with focused, Q-switched Nd:YAG radiation at the wavelength of 1064 nm. The effects of ignition and vapor pressure are discussed in view of the appearance of the emission spectra. The recorded spectra are proportional to the vapor pressure in air. The hydrogen and oxygen contributions diminish gradually with consecutive laser-plasma events without gas flow. The results show that LIBS can be used to characterize organic vapor

Analysis of the transient compressible vapor flow in heat pipes

Science.gov (United States)

Jang, J. H.; Faghri, A.; Chang, W. S.

1989-01-01

The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method. The model is tested for simulated heat pipe vapor flow and actual vapor flow in cylindrical heat pipes. A good comparison of the present transient results for the simulated heat pipe vapor flow with the previous results of a two-dimensional numerical model is achieved and the steady state results are in agreement with the existing experimental data. The transient behavior of the vapor flow under subsonic, sonic, and supersonic speeds and high mass flow rates are successfully predicted. The one-dimensional model also describes the vapor flow dynamics in cylindrical heat pipes at high temperatures.

Analysis of the transient compressible vapor flow in heat pipe

International Nuclear Information System (INIS)

Jang, J.H.; Faghri, A.; Chang, W.S.

1989-07-01

The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method. The model is tested for simulated heat pipe vapor flow and actual vapor flow in cylindrical heat pipes. A good comparison of the present transient results for the simulated heat pipe vapor flow with the previous results of a two-dimensional numerical model is achieved and the steady state results are in agreement with the existing experimental data. The transient behavior of the vapor flow under subsonic, sonic, and supersonic speeds and high mass flow rates are successfully predicted. The one-dimensional model also describes the vapor flow dynamics in cylindrical heat pipes at high temperatures

Headspace vapor characterization of Hanford Waste Tank SX-102: Results from samples collected on July 19, 1995. Tank Vapor Characterization Project

International Nuclear Information System (INIS)

McVeety, B.D.; Evans, J.C.; Clauss, T.W.; Pool, K.H.

1996-05-01

This report describes the results of vapor samples taken from the headspace of waste storage tank 241-SX-102 (Tank SX-102) at the Hanford Site in Washington State. Pacific Northwest National Laboratory (PNNL) contracted with Westinghouse Hanford Company (WHC) to provide sampling devices and analyze samples for inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The analytical work was performed under the PNNL Vapor Analytical Laboratory (VAL) by the Tank Vapor Characterization Project. Work performed was based on a sample and analysis plan (SAP) prepared by WHC. The SAP provided job-specific instructions for samples, analyses, and reporting. The SAP for this sample job was open-quotes Vapor Sampling and Analysis Planclose quotes, and the sample job was designated S5046. Samples were collected by WHC on July 19, 1995, using the vapor sampling system (VSS), a truck-based sampling method using a heated probe inserted into the tank headspace

Headspace vapor characterization of Hanford Waste Tank AX-103: Results from samples collected on June 21, 1995. Tank Vapor Characterization Project

International Nuclear Information System (INIS)

Ligotke, M.W.; Pool, K.H.; Clauss, T.W.

1996-05-01

This report describes the results of vapor samples taken from the headspace of waste storage tank 241-AX-103 (Tank AX-103) at the Hanford Site in Washington State. Pacific Northwest National Laboratory (PNNL) contracted with Westinghouse Hanford Company (WHC) to provide sampling devices and analyze samples for inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The analytical work was performed by the PNNL Vapor Analytical Laboratory (VAL) by the Tank Vapor Characterization Project. Work performed was based on a sample and analysis plan (SAP) prepared by WHC. The SAP provided job-specific instructions for samples, analyses, and reporting. The SAP for this sample job was open-quotes Vapor Sampling and Analysis Planclose quotes, and the sample job was designated S5029. Samples were collected by WHC on June 21, 1995, using the Vapor Sampling System (VSS), a truck-based sampling method using a heated probe inserted into the tank headspace

Headspace vapor characterization of Hanford Waste Tank AX-101: Results from samples collected on June 15, 1995. Tank Vapor Characterization Project

International Nuclear Information System (INIS)

Pool, K.H.; Clauss, T.W.; Evans, J.C.; McVeety, B.D.

1996-05-01

This report describes the results of vapor samples taken from the headspace of waste storage tank 241-AX-101 (Tank AX-101) at the Hanford Site in Washington State. Pacific Northwest National Laboratory (PNNL) contracted with Westinghouse Hanford Company (WHC) to provide sampling devices and analyze samples for inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The analytical work was performed by the PNNL Vapor Analytical Laboratory (VAL) under the Tank Vapor Characterization Project. Work performed was based on a sample and analysis plan (SAP) prepared by WHC. The SAP provided job-specific instructions for samples, analyses, and reporting. The SAP for this sample job was open-quotes Vapor Sampling and Analysis Planclose quotes, and the sample job was designated S5028. Samples were collected by WHC on June 15, 1995, using the Vapor Sampling System (VSS), a truck-based sampling method using a heated probe inserted into the tank headspace

46 CFR 182.480 - Flammable vapor detection systems.

Science.gov (United States)

2010-10-01

... 100 GROSS TONS) MACHINERY INSTALLATION Specific Machinery Requirements § 182.480 Flammable vapor... permit calibration in a vapor free atmosphere. (g) Electrical connections, wiring, and components for a...

External fuel vaporization study, phase 2

Science.gov (United States)

Szetela, E. J.; Chiappetta, L.

1981-01-01

An analytical study was conducted to evaluate the effect of variations in fuel properties on the design of an external fuel vaporizaton system. The fuel properties that were considered included thermal stability, critical temperature, enthalpy a critical conditions, volatility, and viscosity. The design parameters that were evaluated included vaporizer weight and the impact on engine requirement such as maintenance, transient response, performance, and altitude relight. The baseline fuel properties were those of Jet A. The variation in thermal stability was taken as the thermal stability variation for Experimental Referee Broad Specification (ERBS) fuel. The results of the analysis indicate that a change in thermal stability equivalent to that of ERBS would increase the vaporization system weight by 20 percent, decrease oprating time between cleaning by 40 percent and make altitude relight more difficult. An increase in fuel critical temperature of 39 K would require a 40 percent increase in vaporization system weight. The assumed increase in enthalpy and volatility would also increase vaporizer weight by 40 percent and make altitude relight extremely difficult. The variation in fuel viscosity would have a negligible effect on the design parameters.

Numerical analysis of fragmentation mechanisms in vapor explosions

Energy Technology Data Exchange (ETDEWEB)

Koshizuka, Seiichi; Ikeda, Hirokazu; Oka, Yoshiaki [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

1998-01-01

Fragmentation of molten metal is the key process in vapor explosions. However this process is so rapid that the mechanisms have not been clarified yet in the experimental studies. Besides, numerical simulation is difficult because we have to analyze water, steam and molten metal simultaneously with evaporation and fragmentation. The authors have been developing a new numerical method, the Moving Particle Semi-implicit (MPS) method, based on moving particles and their interactions. Grids are not necessary. Incompressible flows with fragmentation on free surfaces have been calculated successfully using the MPS method. In the present study numerical simulation of the fragmentation processes using the MPS method is carried out to investigate the mechanisms. A numerical model to calculate evaporation from water to steam is developed. In this model, new particles are generated on water-steam interfaces. Effect of evaporation is also investigated. Growth of the filament is not accelerated when the normal evaporation is considered. This is because the normal evaporation needs a longer time than the moment of the jet impingement, though the filament growth is decided in this moment. Next, rapid evaporation based on spontaneous nucleation is considered. The filament growth is markedly accelerated. This result is consistent with the experimental fact that the spontaneous nucleation temperature is a necessary condition of small-scale vapor explosions. (J.P.N.)

In-situ water vaporization improves bitumen production during electrothermal processes

Energy Technology Data Exchange (ETDEWEB)

Wang, J. [Calgary Univ., AB (Canada); McGee, B. [E-T Energy, Calgary, AB (Canada); Kantzas, A. [Calgary Univ., AB (Canada). Tomographic Imaging and Porous Media Laboratory

2008-10-15

Electro-thermal processes are now being considered as an alternative or complementary process to steam injection processes. This study used an in situ vaporized water process to optimize electrothermal processes for steam injection enhanced oil recovery (EOR). A simulation tool was used to model electro-thermal processes in an Athabasca oil sands reservoir. Incremental oil recovery was estimated based on a 3-block conceptual model. A field scale model was then used to investigate the effects of electrode spacing, water injection rates, and electrical heating rates on bitumen recovery. Results of the simulation studies were then analyzed using a statistical tool in order to determine optimal conditions for maximizing bitumen production. Results of the study showed that incremental recovery using the water vaporization technique resulted in oil recovery rates of 25 per cent original oil in place (OOIP). Sensitivity analyses showed that medium electrical heating rates, low water injection rates, and small spacings between electrodes maximized bitumen production rates. It was concluded that the technique can be used alone or combined with other methods to economically produce bitumens. 2 refs., 7 tabs., 9 figs.

Using the SPoRT POES/GOES Hybrid Product in OCONUS Forecasting

Science.gov (United States)

Smith, Matt; Fuell, Kevin; Nelson, Jim

2014-01-01

The SPoRT (Short-term Prediction and Research Transition) Program at the NASA/Marshall Space Flight Center has been providing unique NASA and NOAA data and techniques to partner Weather Forecast Offices (WFOs) for ten years. Data are provided in the Decision Support System used by WFO forecasters: AWIPS. For the last couple of years, SPoRT has been producing the POES/GOES Hybrid. This suite of products combines the strength ofl5- minute animations of GOES imagery - providing temporal continuity, with the higher resolution, relatively random availability, of polar orbiting (POES) imagery data. The product was first introduced with only MODIS data from NASA's Terra and Aqua satellites, but recently the VIIRS instrument onboard the Suomi-NPP satellite was added, providing better high-resolution coverage. These products represent SPoRT's efforts to prepare for higher resolution, higher frequency GOES-R imagery - as well as helping to move VIIRS (JPSS) data into the mainstream of weather forecasting. SPoRT generates 5 products for this dataset: Visible, Longwave Infrared (11 micrometers), Shortwave IR (3.7 micrometers), Water Vapor (6.7 micrometers), and Fog (Difference of 11 micrometer and 3.7 micrometer channels). The Water Vapor hybrid product has a Red-Blue-Green image from MODIS inlaid, since it provides even more qualitative information than water vapor alone. Animated examples of the products will be shown in this presentation. While the resolution at nadir of GOES imagery is nominally Han (4km for IR channels), the inlaid polar orbiter imagery has a resolution of 250m (lkm for IR channels). This has tremendous application in the continental US. However, in high latitudes, since the usefulness of GOES degrades poleward rapidly, the contrast of GOES and POES data is stark. The consistent temporal nature of GOES, even though at a reduced resolution at high latitudes, provides basic situational awareness, but the introduction of polar data is very helpful in seeing

Impact of geographic variations of the convective and dehydration center on stratospheric water vapor over the Asian monsoon region

Directory of Open Access Journals (Sweden)

K. Zhang

2016-06-01

Full Text Available The Asian monsoon region is the most prominent moisture center of water vapor in the lower stratosphere (LS during boreal summer. Previous studies have suggested that the transport of water vapor to the Asian monsoon LS is controlled by dehydration temperatures and convection mainly over the Bay of Bengal and Southeast Asia. However, there is a clear geographic variation of convection associated with the seasonal and intra-seasonal variations of the Asian monsoon circulation, and the relative influence of such a geographic variation of convection vs. the variation of local dehydration temperatures on water vapor transport is still not clear. Using satellite observations from the Aura Microwave Limb Sounder (MLS and a domain-filling forward trajectory model, we show that almost half of the seasonal water vapor increase in the Asian monsoon LS are attributable to geographic variations of convection and resultant variations of the dehydration center, of which the influence is comparable to the influence of the local dehydration temperature increase. In particular, dehydration temperatures are coldest over the southeast and warmest over the northwest Asian monsoon region. Although the convective center is located over Southeast Asia, an anomalous increase of convection over the northwest Asia monsoon region increases local diabatic heating in the tropopause layer and air masses entering the LS are dehydrated at relatively warmer temperatures. Due to warmer dehydration temperatures, anomalously moist air enters the LS and moves eastward along the northern flank of the monsoon anticyclonic flow, leading to wet anomalies in the LS over the Asian monsoon region. Likewise, when convection increases over the Southeast Asia monsoon region, dry anomalies appear in the LS. On a seasonal scale, this feature is associated with the monsoon circulation, convection and diabatic heating marching towards the northwest Asia monsoon region from June to August. The

Mineralogy and Thermal Properties of V-Type Asteroid 956 Elisa: Evidence for Diogenitic Material from the Spitzer IRS (5-35 Micrometers) Spectrum

Science.gov (United States)

Lim, Lucy F.; Emery, Joshua P.; Moskovitz, Nicholas A.

2010-01-01

We present the thermal infrared (5-35 micrometer) spectrum of 956 Elisa as measured by the Spitzer Infrared Spectrograph ("IRS"; Houck,1.R. et .11. [20041. Astrophys, 1. SuppL 154, 18-24) together with new ground-based lightcurve data and near-IR spectra. From the visible lightcurve photometry, we determine a rotation period of 16.494 +/- 0.001 h, identify the rotational phase of the Spitzer observations, and estimate the visible absolute magnitude (Hv) at that rotational phase to be 12.58 +/- 0.04. From radiometric analysis of the thermal flux spectrum, we find that at the time of observation 956 Elisa had a projected radius of 5.3 +/- 0.4 km with a visible albedo pv = 0.142+/- 0.022, significantly lower than that of the prototype V-type asteroid, 4 Vesta. (This corresponds to a radius of 5.2 +/- 0.4 km at lightcurve mean.) Analysis with the standard thermal model (STM) results in a sub-solar temperature of 292.3 +/- 2.8 K and beaming parameter eta = 1.16 +/- 0.05. Thermophysical modeling places a lower limit of 20 J m(exp -2)K(exp -1)s(exp -1/2) on the thermal inertia of the asteroid's surface layer (if the surface is very smooth) but more likely values fall between 30 and 150 J m(exp -2)K(exp -1)s(exp -1/2) depending on the sense of rotation. The emissivity spectrum, calculated by dividing the measured thermal flux spectrum by the modeled thermal continuum, exhibits mineralogically interpretable spectral features within the 9-12 micrometer reststrahlen band, the 15-16.5 micrometer Si-O-Si stretching region, and the 16-25 micrometer reststrahlen region that are consistent with pyroxene of diogenitic composition: extant diogenitic pyroxenes fall within the narrow compositional range W0(sub 2+/-1)En(sub 74+/-2)Fs(sub 24+/-1). Spectral deconvolution of the 9-12 micrometer reststrahlen features indicates that up to approximately 20% olivine may also be present, suggesting an olivine-diogenite-like mineralogy. The mid-IR spectrum is inconsistent with non

GAUGE R&R FOR AN OPTICAL MICROMETER INDUSTRIAL TYPE MACHINE

Directory of Open Access Journals (Sweden)

Georgia A. Louka

2010-12-01

Full Text Available The measurement of the uncertainty of a metric system, as 'Gauge R&R' and the collation of results between the Xbar & R and the ANOVA method, are extended in this essay. In an academic school laboratory we accomplished a sequence of measurements with the use of an Optical Micrometer Industrial Type Machine (MUL 300. This paper analyzes the measurement system that used in the laboratory and checks the reasons of the variability's provocation that observed in the machine, between the theoretical calculations and measurements. In order to find out this problem, we will use the 'Gage Repeatability and Reproducibility' technique of Measurement System Analysis (M.S.A.. This technique uses analysis of variance. In addition, will use Minitab program in order to find out the factors that we have in the whole experiment as enlarge the problem of measurements. In this paper, a statistical method using the correlation between Gage R&R and process capability indices is proposed for evaluating the adequacy of the acceptance criteria of P/T ratio. Finally, a comparative analysis has also been performed for evaluating the accuracy of Gage R&R between two methods (ANOVA and R- Xbar method. Hopefully, the results of this research can provide a useful reference for quality practitioners in various industries.

Vaporization of Samarium trichloride studied by thermogravimetry

International Nuclear Information System (INIS)

Esquivel, Marcelo R.; Pasquevich, Daniel M.

2003-01-01

In the present work, the vaporization reaction of SmCl 3 (l) obtained from the 'in situ' reaction of Sm 2 O 3 (s) and Cl 2 (g)-C(s) was studied by thermogravimetry under controlled atmosphere. The effects of both the temperature between 825 C degrees and 950 C degrees and the total flow gas on the vaporization rate of the following reaction: SmCl 3 (l) = SmCl 3 (g) were analyzed. The vaporization rate of the process was found to be independent of then total gas flow rate and highly dependent on the temperature. E ap calculation led to a value of 240 ± 10 kJ.mol -1 . A comparison between this value and that of the molar enthalpy of vaporization allow to the conclusion that the reaction occur in conditions near to equilibrium. The SmCl 3 identity was determined by X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). (author)

General well function for soil vapor extraction

Science.gov (United States)

Perina, Tomas

2014-04-01

This paper develops a well function applicable to extraction of groundwater or soil vapor from a well under the most common field test conditions. The general well function (Perina and Lee, 2006) [12] is adapted to soil vapor extraction and constant head boundary at the top. For groundwater flow, the general well function now applies to an extraction well of finite diameter with uniform drawdown along the screen, finite-thickness skin, and partially penetrating an unconfined, confined, and leaky aquifer, or an aquifer underneath a reservoir. With a change of arguments, the model applies to soil vapor extraction from a vadose zone with no cover or with leaky cover at the ground surface. The extraction well can operate in specified drawdown (pressure for soil vapor) or specified flowrate mode. Frictional well loss is computed as flow-only dependent component of the drawdown inside the extraction well. In general case, the calculated flow distribution is not proportional to screen length for a multiscreen well.

Solvent vapor annealing of an insoluble molecular semiconductor

KAUST Repository

Amassian, Aram

2010-01-01

Solvent vapor annealing has been proposed as a low-cost, highly versatile, and room-temperature alternative to thermal annealing of organic semiconductors and devices. In this article, we investigate the solvent vapor annealing process of a model insoluble molecular semiconductor thin film - pentacene on SiO 2 exposed to acetone vapor - using a combination of optical reflectance and two-dimensional grazing incidence X-ray diffraction measurements performed in situ, during processing. These measurements provide valuable and new insight into the solvent vapor annealing process; they demonstrate that solvent molecules interact mainly with the surface of the film to induce a solid-solid transition without noticeable swelling, dissolving or melting of the molecular material. © 2010 The Royal Society of Chemistry.

Vaporization of comet nuclei: Light curves and life times

Energy Technology Data Exchange (ETDEWEB)

Cowan, J J [Harvard Univ., Cambridge, MA (USA). Center for Astrophysics; A' Hearn, M F [Maryland Univ., College Park (USA)

1979-10-01

The authors have examined the effects of vaporization from the nucleus of a comet and show that a latitude dependence of vaporization can, in some cases, explain asymmetries in commetary light curves. They also find that a non-uniform distribution of solar radiation over a comet can considerably shorten the vaporization lifetime compared to the results normally obtained by assuming that the nuclear surface is isothermal. Independent of any latitude effects, comets with CO/sub 2/-dominated nuclei and with periherlion distances less than 0.5 AU have vaporization lifetimes less than or comparable to their dynamical ejection times. This may explain the observed deficit of comets with small perihelion distances. Similarly comets with CO/sub 2/-dominated nuclei and perihelia near Jupiter's orbit have vaporization lifetimes that are shorter than the time for capture into short-period orbits. They suggest, therefore, that at least some new comets are composed in large part of CO/sub 2/, while only H/sub 2/O-dominated comets, with lower vaporization rates, can survive to be captured into short-period orbits.

Supramolecular structure of a perylene derivative in thin films made by vacuum thermal evaporation

International Nuclear Information System (INIS)

Fernandes, Jose Diego

2015-01-01

The supramolecular arrangement of organic thin films is a factor that influences both optical and electrical properties of these films and, consequently, the technological applications involving organic electronics. In this dissertation, thin films of a perylene derivative (bis butylimido perylene, acronym BuPTCD) were produced by physical vapor deposition (PVD) using vacuum thermal evaporation. The aim of this work was to investigate the supramolecular arrangement of BuPTCD films, which implies to control the thickness at nanometer scale and to determine the molecular organization, the morphology (at nano and micrometer scales) and the crystallinity, besides the stability of this arrangement as a function of the temperature. Optical properties (such as absorption and emission) and electrical properties (such as conductivity and photoconductivity) were also determined. The UV-Vis absorption spectra revealed a controlled growth (uniform) of the BuPTCD films. Atomic force and optical microscopy images showed a homogeneous surface of the film at nano and micrometer scales, respectively. The X-ray diffraction showed that the BuPTCD powder and PVD film have different crystalline structures, with the BuPTCD molecules head-on oriented in the PVD films, supported on the substrate surface by the side group (FTIR). This structure favors the light emission (photoluminescence) by the formation of excimers. The thermal treatment (200°C for 10 min) does not affect the molecular organization of the PVD films, showing a thermal stability of the BuPTCD supramolecular arrangement under these circumstances. The electrical measurements (DC) showed a linear increase of the current as a function of the tension, which is characteristic of ohmic behavior. Also, the films exhibited an increase of current by 2 orders of magnitude when exposed to light (photoconductive properties). Finally, BuPTCD films were exposed to vapor of trifluoroacetic acid (TFA) to verify the sensitivity of the Bu

46 CFR 39.40-1 - General requirements for vapor balancing-TB/ALL.

Science.gov (United States)

2010-10-01

... Section 39.40-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS VAPOR CONTROL SYSTEMS... to control vapor emissions during a lightering or topping-off operation which does not use vapor... compressor or blower to assist vapor transfer without approval from the Commandant (CG-522). (d) Vapor...

Monitoring tropospheric water vapor changes using radiosonde data

International Nuclear Information System (INIS)

Elliott, W.P.; Smith, M.E.; Angell, J.K.

1990-01-01

Significant increases in the water vapor content of the troposphere are expected to accompany temperature increases due to rising concentrations of the greenhouse gases. Thus it is important to follow changes in water vapor over time. There are a number of difficulties in developing a homogeneous data set, however, because of changes in radiosonde instrumentation and reporting practices. The authors report here on preliminary attempts to establish indices of water vapor which can be monitored. The precipitable water between the surface and 500 mb is the first candidate. They describe their method for calculating this quantity from radiosonde data for a network very similar to the network Angell uses for detecting temperature trends. Preliminary results suggest that the noise level is low enough to detect trends in water vapor at the individual stations. While a slight increase in global water vapor is hinted at in the data, and the data suggest there may have been a net transfer of water from the Southern Hemisphere to the Northern Hemisphere, these conclusions are tentative. The authors also discuss the future course of this investigation

Secondhand Exposure to Vapors From Electronic Cigarettes

Science.gov (United States)

Czogala, Jan; Fidelus, Bartlomiej; Zielinska-Danch, Wioleta; Travers, Mark J.; Sobczak, Andrzej

2014-01-01

Introduction: Electronic cigarettes (e-cigarettes) are designed to generate inhalable nicotine aerosol (vapor). When an e-cigarette user takes a puff, the nicotine solution is heated and the vapor is taken into lungs. Although no sidestream vapor is generated between puffs, some of the mainstream vapor is exhaled by e-cigarette user. The aim of this study was to evaluate the secondhand exposure to nicotine and other tobacco-related toxicants from e-cigarettes. Materials and Methods: We measured selected airborne markers of secondhand exposure: nicotine, aerosol particles (PM2.5), carbon monoxide, and volatile organic compounds (VOCs) in an exposure chamber. We generated e-cigarette vapor from 3 various brands of e-cigarette using a smoking machine and controlled exposure conditions. We also compared secondhand exposure with e-cigarette vapor and tobacco smoke generated by 5 dual users. Results: The study showed that e-cigarettes are a source of secondhand exposure to nicotine but not to combustion toxicants. The air concentrations of nicotine emitted by various brands of e-cigarettes ranged from 0.82 to 6.23 µg/m3. The average concentration of nicotine resulting from smoking tobacco cigarettes was 10 times higher than from e-cigarettes (31.60±6.91 vs. 3.32±2.49 µg/m3, respectively; p = .0081). Conclusions: Using an e-cigarette in indoor environments may involuntarily expose nonusers to nicotine but not to toxic tobacco-specific combustion products. More research is needed to evaluate health consequences of secondhand exposure to nicotine, especially among vulnerable populations, including children, pregnant women, and people with cardiovascular conditions. PMID:24336346

Does mercury vapor exposure increase urinary selenium excretion

Energy Technology Data Exchange (ETDEWEB)

Hongo, T; Suzuki, T; Himeno, S; Watanabe, C; Satoh, H; Shimada, Y

1985-01-01

It has been reported that an increase of urinary selenium excretion may occur as a result of mercury vapor exposure. However, experimental data regarding the interaction between mercury vapor and selenium have yielded ambiguous results about the retention and elimination of selenium due to mercury vapor exposure and the decrease of selenium excretion due to mercury in the form of mercuric mercury (Hg/sup 2 +/). In this study, the authors measured urinary mercury and selenium in workers with or without exposure to mercury vapor to determine whether or not urinary selenium excretion was increased as a result of mercury vapor exposure. Urine samples were collected from 141 workers, 71 men and 70 women, whose extent of exposure to mercury vapor varied according to their job sites. Workers were divided into five groups according to their urinary mercury levels. The mercury level in group I was less than 2.8 nmol/mmol creatinine which means that this group was mostly free from mercury exposure. The average age was almost identical among the groups. For both sexes, group V (with the highest urinary mercury level) had the lowest urinary selenium level, but one-way variance analysis (ANOVA) did not reveal any significant variations of urinary selenium with urinary mercury levels; however, a weak but significant negative correlation between mercury and selenium was found in men.

A novel approach for preparation of micrometer-sized, monodisperse dimple and hemispherical polystyrene particles.

Science.gov (United States)

Tanaka, Takuya; Komatsu, Yoshifumi; Fujibayashi, Teruhisa; Minami, Hideto; Okubo, Masayoshi

2010-03-16

Micrometer-sized, monodisperse dimple and hemispherical polystyrene (PS) particles were successfully prepared by heating (55-70 degrees C) of spherical PS particles dispersed in methanol/water media (40/60 to 80/20, w/w) in the presence of decane droplets, and subsequent cooling down to room temperature. Decane was absorbed by the PS particles during the heating process. Decane-absorbed PS particles phase-separated into PS and decane phases in the inside during the cooling process, and eventually dimple and/or hemispherical particles were formed by removal of the decane phase from phase-separated PS/decane particles by evaporation. The size of the dimple, which is determined by the volume of decane phase-separated from decane-absorbed PS particles during the cooling process, increased with increases in the heating temperature and the methanol content.

Water-vapor pressure control in a volume

Science.gov (United States)

Scialdone, J. J.

1978-01-01

The variation with time of the partial pressure of water in a volume that has openings to the outside environment and includes vapor sources was evaluated as a function of the purging flow and its vapor content. Experimental tests to estimate the diffusion of ambient humidity through openings and to validate calculated results were included. The purging flows required to produce and maintain a certain humidity in shipping containers, storage rooms, and clean rooms can be estimated with the relationship developed here. These purging flows are necessary to prevent the contamination, degradation, and other effects of water vapor on the systems inside these volumes.

Water vapor retrieval over many surface types

Energy Technology Data Exchange (ETDEWEB)

Borel, C.C.; Clodius, W.C.; Johnson, J.

1996-04-01

In this paper we present a study of of the water vapor retrieval for many natural surface types which would be valuable for multi-spectral instruments using the existing Continuum Interpolated Band Ratio (CIBR) for the 940 nm water vapor absorption feature. An atmospheric code (6S) and 562 spectra were used to compute the top of the atmosphere radiance near the 940 nm water vapor absorption feature in steps of 2.5 nm as a function of precipitable water (PW). We derive a novel technique called ``Atmospheric Pre-corrected Differential Absorption`` (APDA) and show that APDA performs better than the CIBR over many surface types.

Fluid-to-fluid scaling for a gravity- and flashing-driven natural circulation loop

International Nuclear Information System (INIS)

Yadigaroglu, G.; Zeller, M.

1994-01-01

In certain natural-circulation reactor systems proposed recently, vapor generation takes place by flashing in an adiabatic riser above the core. A step-by-step facility design procedure was used to define suitable scaling criteria for a refrigerant-113 (R-113) experiment simulating the dynamics and stability of such a loop. The fact that vapor generation does not normally take place in the core allows additional flexibility in designing the model; almost perfect simulation can be achieved, mainly by reducing the height of the facility according to the liquid density ratio and scaling for similar void fraction distributions in the prototype and the model. ((orig.))

Review of enhanced vapor diffusion in porous media

International Nuclear Information System (INIS)

Webb, S.W.; Ho, C.K.

1998-01-01

Vapor diffusion in porous media in the presence of its own liquid has often been treated similar to gas diffusion. The gas diffusion rate in porous media is much lower than in free space due to the presence of the porous medium and any liquid present. However, enhanced vapor diffusion has also been postulated such that the diffusion rate may approach free-space values. Existing data and models for enhanced vapor diffusion, including those in TOUGH2, are reviewed in this paper

Microscale interfacial behavior at vapor film collapse on high-temperature particle surface

International Nuclear Information System (INIS)

Abe, Yutaka; Tochio, Daisuke

2009-01-01

It has been pointed out that vapor film on a premixed high-temperature droplet surface should be collapsed to trigger vapor explosion. Thus, it is important to clarify the micromechanism of vapor film collapse behavior for the occurrence of vapor explosion. In the present study, microscale vapor-liquid interface behavior upon vapor film collapse caused by an external pressure pulse is experimentally observed and qualitatively analyzed. In the analytical investigation, interfacial temperature and interface movement were estimated with heat conduction analysis and visual data processing technique. Results show that condensation can possibly occur at the vapor-liquid interface when the pressure pulse arrived. That is, this result indicates that the vapor film collapse behavior is dominated not by fluid motion but by phase change. (author)

Headspace vapor characterization of Hanford Waste Tank 241-T-110: Results from samples collected on August 31, 1995. Tank Vapor Characterization Project

International Nuclear Information System (INIS)

McVeety, B.D.; Thomas, B.L.; Evans, J.C.

1996-05-01

This report describes the results of vapor samples taken from the headspace of waste storage tank 241-T-110 (Tank T-110) at the Hanford Site in Washington State. Pacific Northwest National Laboratory (PNNL) contracted with Westinghouse Hanford Company (WHC) to provide sampling devices and analyze samples for inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The analytical work was performed by the PNNL Vapor Analytical Laboratory (VAL) by the Tank Vapor Characterization Project. Work performed was based on a sample and analysis plan (SAP) prepared by WHC. The SAP provided job-specific instructions for samples, analyses, and reporting. The SAP for this sample job was open-quotes Vapor Sampling and Analysis Planclose quotes, and the sample job was designated S5056. Samples were collected by WHC on August 31, 1995, using the Vapor Sampling System (VSS), a truck-based sampling method using a heated probe inserted into the tank headspace

Headspace vapor characterization of Hanford Waste Tank 241-TX-111: Results from samples collected on October 12, 1995. Tank Vapor Characterization Project

International Nuclear Information System (INIS)

Pool, K.H.; Clauss, T.W.; Evans, J.C.

1996-06-01

This report describes the results of vapor samples taken from the headspace of waste storage tank 241-TX-111 (Tank TX-111) at the Hanford Site in Washington State. Pacific Northwest National Laboratory (PNNL) contracted with Westinghouse Hanford Company (WHC) to provide sampling devices and analyze samples for inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The analytical work was performed by the PNNL Vapor Analytical Laboratory (VAL) by the Tank Vapor Characterization Project. Work performed was based on a sample and analysis plan (SAP) prepared by WHC. The SAP provided job-specific instructions for samples, analyses, and reporting. The SAP for this sample job was open-quotes Vapor Sampling and Analysis Planclose quotes, and the sample job was designated S5069. Samples were collected by WHC on October 12, 1995, using the Vapor Sampling System (VSS), a truck-based sampling method using a heated probe inserted into the tank headspace

Headspace vapor characterization of Hanford Waste Tank 241-SX-109: Results from samples collected on August 1, 1995. Tank Vapor Characterization Project

International Nuclear Information System (INIS)

Pool, K.H.; Clauss, T.W.; Evans, J.C.

1996-05-01

This report describes the results of vapor samples taken from the headspace of waste storage tank 241-SX-109 (Tank SX-109) at the Hanford Site in Washington State. Pacific Northwest National Laboratory (PNNL) contracted with Westinghouse Hanford Company (WHC) to provide sampling devices and analyze samples for inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The analytical work was performed by the PNNL Vapor Analytical Laboratory (VAL) by the Tank Vapor Characterization Project. Work performed was based on a sample and analysis plan (SAP) prepared by WHC. The SAP provided job-specific instructions for samples, analyses, and reporting. The SAP for this sample job was open-quotes Vapor Sampling and Analysis Planclose quotes, and the sample job was designated S5048. Samples were collected by WHC on August 1, 1995, using the Vapor Sampling System (VSS), a truck-based sampling method using a heated probe inserted into the tank headspace

Headspace vapor characterization of Hanford Waste Tank 241-SX-104: Results from samples collected on July 25, 1995. Tank Vapor Characterization Project

International Nuclear Information System (INIS)

Thomas, B.L.; Clauss, T.W.; Evans, J.C.

1996-05-01

This report describes the results of vapor samples taken from the headspace of waste storage tank 241-SX-104 (Tank SX-104) at the Hanford Site in Washington State. Pacific Northwest National Laboratory (PNNL) contracted with Westinghouse Hanford Company (WHC) to provide sampling devices and analyze samples for inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The analytical work was performed by the PNNL Vapor Analytical Laboratory (VAL) by the Tank Vapor Characterization Project. Work performed was based on a sample and analysis plan (SAP) prepared by WHC. The SAP provided job-specific instructions for samples, analyses, and reporting. The SAP for this sample job was open-quotes Vapor Sampling and Analysis Planclose quotes, and the sample job was designated S5049. Samples were collected by WHC on July 25, 1995, using the Vapor Sampling System (VSS), a truck-based sampling method using a heated probe inserted into the tank headspace

Headspace vapor characterization of Hanford Waste Tank 241-S-112: Results from samples collected on July 11, 1995. Tank Vapor Characterization Project

International Nuclear Information System (INIS)

Clauss, T.W.; Pool, K.H.; Evans, J.C.

1996-05-01

This report describes the results of vapor samples taken from the headspace of waste storage Tank 241-S-112 (Tank S-112) at the Hanford. Pacific Northwest National Laboratory (PNNL) is contracted with Westinghouse Hanford Company (WHC) to provide sampling devices and analyze samples for inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The analytical work was performed by the PNNL Vapor Analytical Laboratory (VAL) by the Tank Vapor Characterization Project. Work performed was based on a sample and analysis plan (SAP) prepared by WHC. The SAP provided job-specific instructions for samples, analyses, and reporting. The SAP for this sample job was open-quotes Vapor Sampling and Analysis Planclose quotes, and the sample job was designated S5044. Samples were collected by WHC on July 11, 1995, using the Vapor Sampling System (VSS), a truck-based sampling method using a heated probe inserted into the tank headspace

Headspace vapor characterization of Hanford Waste Tank 241-SX-105: Results from samples collected on July 26, 1995. Tank Vapor Characterization Project

International Nuclear Information System (INIS)

Pool, K.H.; Clauss, T.W.; Evans, J.C.

1996-05-01

This report describes the results of vapor samples taken from the headspace of waste storage tank 241-SX-105 (Tank SX-105) at the Hanford Site in Washington State. Pacific Northwest National Laboratory (PNNL) contracted with Westinghouse Hanford Company (WHC) to provide sampling devices and analyze samples for inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The analytical work was performed by the PNNL Vapor Analytical Laboratory (VAL) by the Tank Vapor Characterization Project. Work performed was based on a sample and analysis plan (SAP) prepared by WHC. The SAP provided job-specific instructions for samples, analyses, and reporting. The SAP for this sample job was open-quotes Vapor Sampling and Analysis Planclose quotes, and the sample job was designated S5047. Samples were collected by WHC on July 26, 1995, using the Vapor Sampling System (VSS), a truck-based sampling method using a heated probe inserted into the tank headspace

Comparison of vapor sampling system (VSS) and in situ vapor sampling (ISVS) methods on Tanks C-107, BY-108, and S-102. Revision 1

International Nuclear Information System (INIS)

Huckaby, J.L.; Edwards, J.A.; Evans, J.C.

1996-08-01

This report discusses comparison tests for two methods of collecting vapor samples from the Hanford Site high-level radioactive waste tank headspaces. The two sampling methods compared are the truck-mounted vapor sampling system (VSS) and the cart-mounted in-situ vapor sampling (ISVS). Three tanks were sampled by both the VSS and ISVS methods from the same access risers within the same 8-hour period. These tanks have diverse headspace compositions and they represent the highest known level of several key vapor analytes

Evidence for the direct ejection of clusters from non-metallic solids during laser vaporization

International Nuclear Information System (INIS)

Bloomfield, L.A.; Yang, Y.A.; Xia, P.; Junkin, A.L.

1991-01-01

This paper reports on the formation of molecular scale particles or clusters of alkali halides and semiconductors during laser vaporization of solids. By measuring the abundances of cluster ions produced in several different source configurations, the authors have determined that clusters are ejected directly from the source sample and do not need to grow from atomic or molecular vapor. Using samples of mixed alkali halide powders, the authors have found that unalloyed clusters are easily produced in a source that prevents growth from occurring after the clusters leave the sample surface. However, melting the sample or encouraging growth after vaporization lead to the production of alloyed cluster species. The sizes of the ejected clusters are initially random, but the population spectrum quickly becomes structured as hot, unstable-sized clusters decay into smaller particles. In carbon, large clusters with odd number of atoms decay almost immediately. The hot even clusters also decay, but much more slowly. The longest lived clusters are the magic C 50 and C 60 fullerenes. The mass spectrum of large carbon clusters evolves in time from structureless, to only the even clusters, to primarily C 50 and C 60 . If cluster growth is encouraged, the odd clusters reappear and the population spectrum again becomes relatively structureless

Bio-inspired wooden actuators for large scale applications.

Science.gov (United States)

Rüggeberg, Markus; Burgert, Ingo

2015-01-01

Implementing programmable actuation into materials and structures is a major topic in the field of smart materials. In particular the bilayer principle has been employed to develop actuators that respond to various kinds of stimuli. A multitude of small scale applications down to micrometer size have been developed, but up-scaling remains challenging due to either limitations in mechanical stiffness of the material or in the manufacturing processes. Here, we demonstrate the actuation of wooden bilayers in response to changes in relative humidity, making use of the high material stiffness and a good machinability to reach large scale actuation and application. Amplitude and response time of the actuation were measured and can be predicted and controlled by adapting the geometry and the constitution of the bilayers. Field tests in full weathering conditions revealed long-term stability of the actuation. The potential of the concept is shown by a first demonstrator. With the sensor and actuator intrinsically incorporated in the wooden bilayers, the daily change in relative humidity is exploited for an autonomous and solar powered movement of a tracker for solar modules.

In vivo quantification of plant starch reserves at micrometer resolution using X-ray microCT imaging and machine learning.

Science.gov (United States)

Earles, J Mason; Knipfer, Thorsten; Tixier, Aude; Orozco, Jessica; Reyes, Clarissa; Zwieniecki, Maciej A; Brodersen, Craig R; McElrone, Andrew J

2018-03-08

Starch is the primary energy storage molecule used by most terrestrial plants to fuel respiration and growth during periods of limited to no photosynthesis, and its depletion can drive plant mortality. Destructive techniques at coarse spatial scales exist to quantify starch, but these techniques face methodological challenges that can lead to uncertainty about the lability of tissue-specific starch pools and their role in plant survival. Here, we demonstrate how X-ray microcomputed tomography (microCT) and a machine learning algorithm can be coupled to quantify plant starch content in vivo, repeatedly and nondestructively over time in grapevine stems (Vitis spp.). Starch content estimated for xylem axial and ray parenchyma cells from microCT images was correlated strongly with enzymatically measured bulk-tissue starch concentration on the same stems. After validating our machine learning algorithm, we then characterized the spatial distribution of starch concentration in living stems at micrometer resolution, and identified starch depletion in live plants under experimental conditions designed to halt photosynthesis and starch production, initiating the drawdown of stored starch pools. Using X-ray microCT technology for in vivo starch monitoring should enable novel research directed at resolving the spatial and temporal patterns of starch accumulation and depletion in woody plant species. No claim to original US Government works New Phytologist © 2018 New Phytologist Trust.

Metal Vapor Arcing Risk Assessment Tool

Science.gov (United States)

Hill, Monika C.; Leidecker, Henning W.

2010-01-01

The Tin Whisker Metal Vapor Arcing Risk Assessment Tool has been designed to evaluate the risk of metal vapor arcing and to help facilitate a decision toward a researched risk disposition. Users can evaluate a system without having to open up the hardware. This process allows for investigating components at risk rather than spending time and money analyzing every component. The tool points to a risk level and provides direction for appropriate action and documentation.

Excessively High Vapor Pressure of Al-based Amorphous Alloys

Directory of Open Access Journals (Sweden)

Jae Im Jeong

2015-10-01

Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

Droplet size effects on film drainage between droplet and substrate.

Science.gov (United States)

Steinhaus, Benjamin; Spicer, Patrick T; Shen, Amy Q

2006-06-06

When a droplet approaches a solid surface, the thin liquid film between the droplet and the surface drains until an instability forms and then ruptures. In this study, we utilize microfluidics to investigate the effects of film thickness on the time to film rupture for water droplets in a flowing continuous phase of silicone oil deposited on solid poly(dimethylsiloxane) (PDMS) surfaces. The water droplets ranged in size from millimeters to micrometers, resulting in estimated values of the film thickness at rupture ranging from 600 nm down to 6 nm. The Stefan-Reynolds equation is used to model film drainage beneath both millimeter- and micrometer-scale droplets. For millimeter-scale droplets, the experimental and analytical film rupture times agree well, whereas large differences are observed for micrometer-scale droplets. We speculate that the differences in the micrometer-scale data result from the increases in the local thin film viscosity due to confinement-induced molecular structure changes in the silicone oil. A modified Stefan-Reynolds equation is used to account for the increased thin film viscosity of the micrometer-scale droplet drainage case.

Vapor characterization of Tank 241-C-103

International Nuclear Information System (INIS)

Huckaby, J.L.; Story, M.S.

1994-06-01

The Westinghouse Hanford Company Tank Vapor Issue Resolution Program has developed, in cooperation with Northwest Instrument Systems, Inc., Oak Ridge National Laboratory, Oregon Graduate Institute of Science and Technology, Pacific Northwest Laboratory, and Sandia National Laboratory, the equipment and expertise to characterize gases and vapors in the high-level radioactive waste storage tanks at the Hanford Site in south central Washington State. This capability has been demonstrated by the characterization of the tank 241-C-103 headspace. This tank headspace is the first, and for many reasons is expected to be the most problematic, that will be characterized (Osborne 1992). Results from the most recent and comprehensive sampling event, sample job 7B, are presented for the purpose of providing scientific bases for resolution of vapor issues associated with tank 241-C-103. This report is based on the work of Clauss et al. 1994, Jenkins et al. 1994, Ligotke et al. 1994, Mahon et al. 1994, and Rasmussen and Einfeld 1994. No attempt has been made in this report to evaluate the implications of the data presented, such as the potential impact of headspace gases and vapors to tank farm workers health. That and other issues will be addressed elsewhere. Key to the resolution of worker health issues is the quantitation of compounds of toxicological concern. The Toxicology Review Panel, a panel of Pacific Northwest Laboratory experts in various areas, of toxicology, has chosen 19 previously identified compounds as being of potential toxicological concern. During sample job 7B, the sampling and analytical methodology was validated for this preliminary list of compounds of toxicological concern. Validation was performed according to guidance provided by the Tank Vapor Conference Committee, a group of analytical chemists from academic institutions and national laboratories assembled and commissioned by the Tank Vapor Issue Resolution Program

Vapor characterization of Tank 241-C-103

Energy Technology Data Exchange (ETDEWEB)

Huckaby, J.L. [Westinghouse Hanford Co., Richland, WA (United States); Story, M.S. [Northwest Instrument Systems, Inc. Richland, WA (United States)

1994-06-01

The Westinghouse Hanford Company Tank Vapor Issue Resolution Program has developed, in cooperation with Northwest Instrument Systems, Inc., Oak Ridge National Laboratory, Oregon Graduate Institute of Science and Technology, Pacific Northwest Laboratory, and Sandia National Laboratory, the equipment and expertise to characterize gases and vapors in the high-level radioactive waste storage tanks at the Hanford Site in south central Washington State. This capability has been demonstrated by the characterization of the tank 241-C-103 headspace. This tank headspace is the first, and for many reasons is expected to be the most problematic, that will be characterized (Osborne 1992). Results from the most recent and comprehensive sampling event, sample job 7B, are presented for the purpose of providing scientific bases for resolution of vapor issues associated with tank 241-C-103. This report is based on the work of Clauss et al. 1994, Jenkins et al. 1994, Ligotke et al. 1994, Mahon et al. 1994, and Rasmussen and Einfeld 1994. No attempt has been made in this report to evaluate the implications of the data presented, such as the potential impact of headspace gases and vapors to tank farm workers health. That and other issues will be addressed elsewhere. Key to the resolution of worker health issues is the quantitation of compounds of toxicological concern. The Toxicology Review Panel, a panel of Pacific Northwest Laboratory experts in various areas, of toxicology, has chosen 19 previously identified compounds as being of potential toxicological concern. During sample job 7B, the sampling and analytical methodology was validated for this preliminary list of compounds of toxicological concern. Validation was performed according to guidance provided by the Tank Vapor Conference Committee, a group of analytical chemists from academic institutions and national laboratories assembled and commissioned by the Tank Vapor Issue Resolution Program.

Muonium formation and the 'missing fraction' in vapors

International Nuclear Information System (INIS)

Fleming, D.G.; Arseneau, D.J.; Garner, D.M.; Senba, M.; Mikula, R.J.

1983-06-01

The vapor phase fractional polarizations of positive muons thermalizing as the muonium atom (Psub(M)) and in diamagnetic environments (Psub(D)) has been measured in H 2 O, CH 3 OH, C 6 H 14 , C 6 H 12 , CCl 4 , CHCl 3 , CH 2 Cl 2 and TMS, in order to compare with the corresponding fractions measured in the condensed phases. There is a marked contrast in every case, with the vapor phase results being largely understandable in terms of a charge exchange/hot atom model. Unlike the situation in the corresponding liquids, there is no permanent lost fraction in the vapor phase in the limit of even moderately high pressures (approximately 1 atm); at lower pressures, depolarization is due to hyperfine mixing and is believed to be well understood. For vapor phase CH 3 OH, C 6 H 14 , C 6 H 12 , and TMS the relative fractions are found to be pressure dependent, suggesting the importance of termolecular hot atom (or ion) reactions in the slowing-down process. For vapor phase H 2 O and the chloromethanes, the relative fractions are pressure independent. For CCl 4 , Psub(M) = Psub(D) approximately 0.5 in the vapor phase vs. Psub(D) = 1.0 in the liquid phase; fast thermal reactions of Mu likely contribute significantly to this difference in the liquid phase. For H 2 O, Psub(M) approximately 0.9 and Psub(D) approximately 0.1 in the vapor phase vs. Psub(D) approximately 0.6 and Psub(M) approximately 0.2 in the liquid phase. Water appears to be the one unequivocal case where the basic charge exchange/hot atom model is inappropriate in the condensed phase, suggesting, therefore, that radiation-induced 'spur' effects play a major role

A heated vapor cell unit for DAVLL in atomic rubidium

OpenAIRE

McCarron, Daniel J.; Hughes, Ifan G.; Tierney, Patrick; Cornish, Simon L.

2007-01-01

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 transitions in atomic rubidium is described. A 5 cm-long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field...

Vapor pressures and thermophysical properties of selected monoterpenoids

Czech Academy of Sciences Publication Activity Database

Štejfa, V.; Dergal, F.; Mokbel, I.; Fulem, Michal; Jose, J.; Růžička, K.

2015-01-01

Roč. 406, Nov (2015), 124-133 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : monoterpenoids * vapor pressure * heat capacity * ideal - gas thermodynamic properties * vaporization and sublimation enthalpy Subject RIV: BJ - Thermodynamics Impact factor: 1.846, year: 2015

Water vapor estimation using digital terrestrial broadcasting waves

Science.gov (United States)

Kawamura, S.; Ohta, H.; Hanado, H.; Yamamoto, M. K.; Shiga, N.; Kido, K.; Yasuda, S.; Goto, T.; Ichikawa, R.; Amagai, J.; Imamura, K.; Fujieda, M.; Iwai, H.; Sugitani, S.; Iguchi, T.

2017-03-01

A method of estimating water vapor (propagation delay due to water vapor) using digital terrestrial broadcasting waves is proposed. Our target is to improve the accuracy of numerical weather forecast for severe weather phenomena such as localized heavy rainstorms in urban areas through data assimilation. In this method, we estimate water vapor near a ground surface from the propagation delay of digital terrestrial broadcasting waves. A real-time delay measurement system with a software-defined radio technique is developed and tested. The data obtained using digital terrestrial broadcasting waves show good agreement with those obtained by ground-based meteorological observation. The main features of this observation are, no need for transmitters (receiving only), applicable wherever digital terrestrial broadcasting is available and its high time resolution. This study shows a possibility to estimate water vapor using digital terrestrial broadcasting waves. In the future, we will investigate the impact of these data toward numerical weather forecast through data assimilation. Developing a system that monitors water vapor near the ground surface with time and space resolutions of 30 s and several kilometers would improve the accuracy of the numerical weather forecast of localized severe weather phenomena.

Numerical modeling of a vaporizing multicomponent droplet

Science.gov (United States)

Megaridis, C. M.; Sirignano, W. A.

The fundamental processes governing the energy, mass, and momentum exchange between the liquid and gas phases of vaporizing, multicomponent liquid droplets have been investigated. The axisymmetric configuration under consideration consists of an isolated multicomponent droplet vaporizing in a convective environment. The model considers different volatilities of the liquid components, variable liquid properties due to variation of the species concentrations, and non-Fickian multicomponent gaseous diffusion. The bicomponent droplet model was employed to examine the commonly used assumptions of unity Lewis number in the liquid phase and Fickian gaseous diffusion. It is found that the droplet drag coefficients, the vaporization rates, and the related transfer numbers are not influenced by the above assumptions in a significant way.

Vaporization of tungsten-metal in steam at high temperatures

International Nuclear Information System (INIS)

Greene, G.A.; Finfrock, C.C.

2000-01-01

The vaporization of tungsten from the APT spallation target dominates the radiological source term for unmitigated target overheating accidents. Chemical reactions of tungsten with steam which persist to tungsten temperatures as low as 800 C result in the formation of a hydrated tungsten-oxide which has a high vapor pressure and is readily convected in a flowing atmosphere. This low-temperature vaporization reaction essentially removes the oxide film that forms on the tungsten-metal surface as soon as it forms, leaving behind a fresh metallic surface for continued oxidation and vaporization. Experiments were conducted to measure the oxidative vaporization rates of tungsten in steam as part of the effort to quantify the MT radiological source term for severe target accidents. Tests were conducted with tungsten rods (1/8 inch diameter, six inches long) heated to temperatures from approximately 700 C to 1350 C in flowing steam which was superheated to 140 C. A total of 19 experiments was conducted. Fifteen tests were conducted by RF induction heating of single tungsten rods held vertical in a quartz glass retort. Four tests were conducted in a vertically-mounted tube furnace for the low temperature range of the test series. The aerosol which was generated and transported downstream from the tungsten rods was collected by passing the discharged steam through a condenser. This procedure insured total collection of the steam along with the aerosol from the vaporization of the rods. The results of these experiments revealed a threshold temperature for tungsten vaporization in steam. For the two tests at the lowest temperatures which were tested, approximately 700 C, the tungsten rods were observed to oxidize without vaporization. The remainder of the tests was conducted over the temperature range of 800 C to 1350 C. In these tests, the rods were found to have lost weight due to vaporization of the tungsten and the missing weight was collected in the downstream condensate

Using in situ bioventing to minimize soil vapor extraction costs

International Nuclear Information System (INIS)

Downey, D.C.; Frishmuth, R.A.; Archabal, S.R.; Pluhar, C.J.; Blystone, P.G.; Miller, R.N.

1995-01-01

Gasoline-contaminated soils may be difficult to remediate with bioventing because high concentrations of gasoline vapors become mobile when air is injected into the soil. Because outward vapor migration is often unacceptable on small commercial sites, soil vapor extraction (SVE) or innovative bioventing techniques are required to control vapors and to increase soil gas oxygen levels to stimulate hydrocarbon biodegradation. Combinations of SVE, off-gas treatment, and bioventing have been used to reduce the costs normally associated with remediation of gasoline-contaminated sites. At Site 1, low rates of pulsed air injection were used to provide oxygen while minimizing vapor migration. At Site 2, a period of high-rate SVE and off-gas treatment was followed by long-term air injection. Site 3 used an innovative approach that combined regenerative resin for ex situ vapor treatment with in situ bioventing to reduce the overall cost of site remediation. At each of these Air Force sites, bioventing provided cost savings when compared to more traditional SVE methods

Shock wave of vapor-liquid two-phase flow

Institute of Scientific and Technical Information of China (English)

Liangju ZHAO; Fei WANG; Hong GAO; Jingwen TANG; Yuexiang YUAN

2008-01-01

The shock wave of vapor-liquid two-phase flow in a pressure-gain steam injector is studied by build-ing a mathematic model and making calculations. The results show that after the shock, the vapor is nearly com-pletely condensed. The upstream Mach number and the volume ratio of vapor have a great effect on the shock. The pressure and Mach number of two-phase shock con-form to the shock of ideal gas. The analysis of available energy shows that the shock is an irreversible process with entropy increase.

Water vapor movement in freezing aggregate base materials.

Science.gov (United States)

2014-06-01

The objectives of this research were to 1) measure the extent to which water vapor movement results in : water accumulation in freezing base materials; 2) evaluate the effect of soil stabilization on water vapor movement : in freezing base materials;...

High Yield Chemical Vapor Deposition Growth of High Quality Large-Area AB Stacked Bilayer Graphene

Science.gov (United States)

Liu, Lixin; Zhou, Hailong; Cheng, Rui; Yu, Woo Jong; Liu, Yuan; Chen, Yu; Shaw, Jonathan; Zhong, Xing; Huang, Yu; Duan, Xiangfeng

2012-01-01

Bernal stacked (AB stacked) bilayer graphene is of significant interest for functional electronic and photonic devices due to the feasibility to continuously tune its band gap with a vertical electrical field. Mechanical exfoliation can be used to produce AB stacked bilayer graphene flakes but typically with the sizes limited to a few micrometers. Chemical vapor deposition (CVD) has been recently explored for the synthesis of bilayer graphene but usually with limited coverage and a mixture of AB and randomly stacked structures. Herein we report a rational approach to produce large-area high quality AB stacked bilayer graphene. We show that the self-limiting effect of graphene growth on Cu foil can be broken by using a high H2/CH4 ratio in a low pressure CVD process to enable the continued growth of bilayer graphene. A high temperature and low pressure nucleation step is found to be critical for the formation of bilayer graphene nuclei with high AB stacking ratio. A rational design of a two-step CVD process is developed for the growth of bilayer graphene with high AB stacking ratio (up to 90 %) and high coverage (up to 99 %). The electrical transport studies demonstrated that devices made of the as-grown bilayer graphene exhibit typical characteristics of AB stacked bilayer graphene with the highest carrier mobility exceeding 4,000 cm2/V·s at room temperature, comparable to that of the exfoliated bilayer graphene. PMID:22906199

Some empirical rules concerning the vapor pressure curve revisited

International Nuclear Information System (INIS)

Velasco, S.; White, J.A.

2014-01-01

Highlights: • A Claussius–Claperyron equation is obtained in the Pitzer corresponding states scheme. • Some well-known empirical rules for the vapor pressure are rewritten in terms of the Pitzer acentric factor. • The Guggenheim point follows the corresponding state scheme better than the normal boiling point. • The Ambrose–Walton vapor pressure equation yields excellent agreement with NIST data in all considered cases. -- Abstract: A form for the Clausius–Clapeyron vapor-pressure equation is obtained in the Pitzer corresponding states scheme. This equation allows one to rewrite the well-known Trouton, Guldberg, van Laar and Guggenheim rules in terms of the acentric factor ω. The original forms of these empirical rules are recovered for some particular values of ω. The proposed rules are checked by analyzing National Institute of Standards and Technology (NIST) data on the liquid-vapor coexistence curve for 105 fluids. These rules have been also analyzed by using the well-known Ambrose–Walton (AW) vapor pressure equation

Recommended vapor pressure and thermophysical data for ferrocene

Czech Academy of Sciences Publication Activity Database

Fulem, Michal; Růžička, K.; Červinka, C.; Rocha, M.A.A.; Santos, L.M.N.B.F.; Berg, R.F.

2013-01-01

Roč. 57, FEB (2013), 530-540 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : ferrocene * vapor pressure * heat capacity * ideal gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure equation Subject RIV: BJ - Thermodynamics Impact factor: 2.423, year: 2013

Analysis of the transient compressible vapor flow in heat pipe

Science.gov (United States)