UK PubMed Central (United Kingdom)

BackgroundThe expression of human virus surface proteins, as well as other mammalian glycoproteins, is much more efficient in cells of higher eukaryotes rather than yeasts. The limitations...Full Text Available

UK PubMed Central (United Kingdom)

A DNA sequence encoding the A chain of ricin toxin (RTA) from the castor bean plant, Ricinus communis, was placed under GAL1 promoter control and transformed into Saccharomyces cerevisiae. Induction...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundIn Saccharomyces cerevisiae galactose is initially metabolized through the Leloir pathway after which glucose 6-phosphate enters glycolysis. Galactose...Full Text Available

UK PubMed Central (United Kingdom)

The number of nuclear pore complexes (NPCs) in individual nuclei of the yeast Saccharomyces cerevisiae was determined by computer-aided reconstruction of entire nuclei from electron...Full Text Available

UK PubMed Central (United Kingdom)

Baker's yeast (Saccharomyces cerevisiae) has been genetically engineered to ferment the pentose sugar xylose present in lignocellulose biomass. One of the reactions controlling the...Full Text Available

UK PubMed Central (United Kingdom)

Little is known about the conservation of determinants for the identities of tRNAs between organisms. We showed previously that Escherichia coli tyrosine tRNA synthetase can charge the Saccharomyces...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The principle aim of the program was to produce a novel, non-leaching antimicrobial surface for commercial development and future use in the liquid food packaging industry. Antimicrobial surfaces which exist presently have been produced to combat the growth of prokaryotic organisms and usually function as slow release systems. A system which could inhibit eukaryotic growth without contaminating the surrounding 'environment' with the inhibitor was considered of great commercial importance. The remit of this study was concerned with creating a surface which could control the growth of eukaryotic organisms found in fruit juice with particular interest in the yeast, Saccharomyces cerevisiae. Putative antimicrobial surfaces were created by the chemical modification of the test substrate polymers; nylon and ethylvinyl alcohol (EVOH). ...

UK PubMed Central (United Kingdom)

Many of the gene products that participate in nitrogen metabolism are sensitive to nitrogen catabolite repression (NCR), i.e., their expression is decreased to low levels when readily used nitrogen...Full Text Available

UK PubMed Central (United Kingdom)

Efficiency of translation termination relies on the specific recognition of the three stop codons by the eukaryotic translation termination factor eRF1. To date only a few proteins are known to be involved...Full Text Available

UK PubMed Central (United Kingdom)

The electrokinetic patterns of four bacterial species (Bacillus subtilis, Bacillus megaterium, Pseudomonas aeruginosa, and Agrobacterium radiobacter), two yeasts (Saccharomyces cerevisiae and Candida...Full Text Available

UK PubMed Central (United Kingdom)

The delivery of proteins and organelles to the vacuole by autophagy involves membrane rearrangements that result in the formation of large vesicles called autophagosomes. The mechanism underlying autophagosome...Full Text Available

UK PubMed Central (United Kingdom)

CDC7 is an essential gene required for DNA replication in Saccharomyces cerevisiae. Cdc7p homologs have recently been identified in vertebrates, but their role in DNA...Full Text Available

UK PubMed Central (United Kingdom)

Genetic test systems involving microorganisms and liver enzyme preparations may be insufficient to detect compounds that require breakdown by enzymes provided by the microbial flora of the intestinal...Full Text Available

UK PubMed Central (United Kingdom)

In the yeast Saccharomyces cerevisiae, a and α mating-type information is stored in transcriptionally silenced cassettes called HML and HMR....Full Text Available

International Nuclear Information System (INIS)

As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high radiation toxicity and long half-life. In this experiment, the biosorption of "2"4"1Am from solution by a fungus, Saccharomyces cerevisiae (S. cerevisiae), and the effects of various experimental conditions on the biosorption and the mechanism were explored. The preliminary results showed that S. cerevisiae is a very efficient biosorbent. An average of more than 99% of the total "2"4"1Am could be removed by S. cerevisiae of 2.1g/L (dry weight) from "2"4"1Am solutions of 2.22MBq/L -555 MBq/L (Co). The adsorption equilibrium was achieved within 1 hour and the optimum pH ranged 1-3. The culture times of more than 16 hours were suitable and the efficient adsorption of 241Am by the S. cerevisiae could be noted. The ...

UK PubMed Central (United Kingdom)

BackgroundWhen eukaryotic cells are deprived of amino acids, uncharged tRNAs accumulate and activate the conserved GCN2 protein kinase. Activated Gcn2p up-regulates the general amino...Full Text Available

UK PubMed Central (United Kingdom)

We demonstrate that expression of the UGA1, CAN1, GAP1, PUT1, PUT2, PUT4, and DAL4 genes is sensitive to nitrogen catabolite repression. The expression of all these genes, with the exception of UGA1...Full Text Available

UK PubMed Central (United Kingdom)

Toxin-secreting “killer” yeasts were initially identified >40 years ago in Saccharomyces cerevisiae strains infected with a double-stranded RNA “killer”...Full Text Available

UK PubMed Central (United Kingdom)

Transcriptional silencing in Saccharomyces cerevisiae occurs at several genetic loci, including the ribosomal DNA (rDNA). Silencing at telomeres (telomere position effect [TPE])...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The role of intermediate products of dioxygen reduction in cytotoxic effects ascribed to oxygen molecules was studied in vivo using various yeast mutants with changed response to oxygen stress. It has been documented that superoxide radical exerts its deleterious effects on yeast cells directly and the role of other oxygen species derived from it is hardly detectable. Yeast Saccharomyces cerevisiae, however, cannot be considered as a typical eukaryotic organism due to its inability of synthesizing polyunsaturated fatty acids (pufa). These fatty acids are known as main target molecules during oxidative stress and their peroxidation leads to cytotoxic effects. As fatty acid content could be easily manipulated in yeast, this organism was used to evaluate the contribution of pufa peroxidation process to the cytotoxic effects of oxygen. Results obtained show, that yeast cells containing linolenic acid as the main constituent of phospholipids are ...

British Library Electronic Table of Contents (United Kingdom)

Over the decades, basic research in life sciences has profited greatly from the study of the small unicellular fungal species Saccharomyces cerevisiae. This yeast turned out to be key for the identification and understanding of molecular mechanisms that underlay the basic functions of all eukaryotic cells. These include, but are not limited to, the regulatory mechanisms behind cellular reproduction (cell cycle control), cellular morphogenesis (cell polarity, cytoskeleton and membrane trafficking) and the management of cellular information (chromosome biology, transcription and translation). Rapid access to genomic information of many yeast species, combined with bioinformatics analyses, provide information on the evolutionary history of yeasts and the molecular ancestry of their constituen...

Science.gov (United States)

Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) are tryptophan-degrading enzymes. Mammalian IDO expression is induced by cytokines and has antimicrobial and immunomodulatory effects. A major role of mammalian TDO is to supply nicotinamide adenine dinucleotide (NAD(+)). In fungi, the IDO homologue is thought to be expressed constitutively and supply NAD(+), as TDO is absent from their genomes. Here, we reveal the distribution of IDO genes among fungal species and characterize their enzymatic activity. The yeast, Saccharomyces cerevisiae has only one IDO gene, whereas the koji-mold, Aspergillus oryzae has two genes, IDO? and IDO?. The A. oryzae IDO? showed more similar enzymatic properties to those of S. cerevisiae IDO than IDO?, suggesting that the A. oryzae IDO? is a functional homologue of the S. cerevisiae IDO. From the IDO? gene, two isoforms, IDO? and IDO?(+) could be ...

International Nuclear Information System (INIS)

Chorismate mutase, a branch-point enzyme in the aromatic amino acid pathway of Saccharomyces cerevisiae, and also a mutant chorismate mutase with a single amino acid substitution in the C-terminal part of the protein have been purified approximately 20-fold and 64-fold from overproducing strains, respectively. The wild-type enzyme is activated by tryptophan and subject to feedback inhibition by tyrosine, whereas the mutant enzyme does not respond to activation by tryptophan nor inhibition by tyrosine. Both enzymes are dimers consisting of two identical subunits of M_r 30,000, each one capable of binding one substrate and one activator molecule. Each subunit of the wild-type enzyme also binds one inhibitor molecule, whereas the mutant enzyme lost this ability. The enzyme reaction was observed by "1H NMR and shows a direct and irreversible conversion of chorismate to prephenate without the accumulation of any enzyme-free intermediates. The ...

Energy Technology Data Exchange (ETDEWEB)

We report an analysis of four strains of baker's yeast (Saccharomyces cerevisiae) using biocavity laser spectroscopy. The four strains are grouped in two pairs (wild type and altered), in which one strain differs genetically at a single locus, affecting mitochondrial function. In one pair, the wild-type rho+ and a rho0 strain differ by complete removal of mitochondrial DNA (mtDNA). In the second pair, the wild-type rho+ and a rho- strain differ by knock-out of the nuclear gene encoding Cox4, an essential subunit of cytochrome c oxidase. The biocavity laser is used to measure the biophysical optic parameter Deltalambda, a laser wavelength shift relating to the optical density of cell or mitochondria that uniquely reflects its size and biomolecular composition. As such, Deltalambda is a powerful parameter that rapidly interrogates the biomolecular state of single cells and mitochondria. Wild-type cells and mitochondria produce ...

Energy Technology Data Exchange (ETDEWEB)

Ethanol has excellent fuel properties, such as high octane, high heat of vaporization and low photochemical reactivity in the atmosphere. It is less volatile than gasoline and there is lower smog formation from evaporative emissions of pure ethanol compared to gasoline. As such, ethanol has emerged as an important alternative energy source that is sustainable, efficient, cost effective, convenient and safe. In 2006, global production of ethanol reached 13.5 billion gallons, up from 12.1 billion gallons in 2005. However, in light of the current debate of food versus fuel, the industry must shift to non-food feedstocks. This paper described an emerging technology to cost-effectively produce ethanol from sweet sorghum stalks, the most promising alternative feedstock to corn, via solid state fermentation (SSF). Experiments of advanced solid state fermentation (ASSF) for ethanol production from sweet sorghum by Saccharomyces cerevisiae were ...

UK PubMed Central (United Kingdom)

We have isolated a second gene (MLS1), which in addition to DAL7, encodes malate synthase from S. cerevisiae. Expression of the two genes is specific for their physiological roles in carbon and nitrogen...Full Text Available

UK PubMed Central (United Kingdom)

cdc18+ of Schizosaccharomyces pombe is a periodically expressed gene that is required for entry into S phase and for the coordination of S phase with mitosis. cdc18+ is related to the Saccharomyces...Full Text Available

Environmental Research Database

DescriptionThis project is part of the BBSRCs special initiative on plant and microbial metabolomics. The project will primarily focus on the trichothecene mycotoxin producing Ascomycete fungus Fusarium graminearum (Fg) which causes ear blight disease of small grain cereals. The project aims to explore the metabolome of various wild-type and single gene deletion Fg strains and to compare some of these with the identical gene mutation in the budding yeast, S. cerevisiae (Sc) and the saprophytic filamentous [continued...

International Science & Technology Center (ISTC)

Development of Technology for Metal Surface Decontamination in Aqueous Solutions

Energy Technology Data Exchange (ETDEWEB)

Eight culture-collection yeast strains of various species and five newly isolated stains were tested for both growth in olive oil extraction effluents and fermentation of the sugars in the same media. The culture-collection yeast strains did not grow in an effluent containing 2.86% sugar (w/v), 8 g/litre phenolic substances, 4.58 g/litre titratable acidity and pH 4.96, whereas the newly isolated strains of Torulopsis sp. MK-1, Saccharomyces norbensis MC-1, S. oleaceus MC-2 and S. oleaginosus grew well and fermented the sugars. In the medium mentioned above, they produced alcohol in amounts of 1.63 to 1.38%, respectively. None of the yeasts grew in an olive oil extraction effluent vacuum-concentrated to over 13-14% of dry matter. The strain of T. sp. MK-1 showed a higher stability.

Science.gov (United States)

... spatially defined fashion. Many surface modification techniques require a sequential chemical treatment of the surface.6 ...

Science.gov (United States)

Surface crystallization and surface-to-bulk ratio in high-level waste glasses.

Energy Technology Data Exchange (ETDEWEB)

A fuzzy-decision-making procedure is applied to find the optimal feed policy of a fed-batch fermentation process for fuel ethanol production using a genetically engineered Saccharomyces yeast 1400 (pLNH33). The policy consisted of feed flow rate, feed concentration, and fermentation time. The recombinant yeast 1400 (pLNH33) can utilize glucose and xylose simultaneously to produce ethanol. However, the parent yeast utilizes glucose only. A partially selective model is used to describe the kinetic behavior of the process. In this study, this partially selective fermentation process is formulated as a general multiple-objective optimal control problem. By using an assigned membership function for each of the objectives, the general multiple-objective optimization problem can be converted into a maximizing decision problem. In order to obtain a global solution, a hybrid method of differential evolution is introduced to solve the maximizing decision problem. A simple ...

International Science & Technology Center (ISTC)

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

Energy Technology Data Exchange (ETDEWEB)

Work continued on the correlations of catalytic activity of metals and surface structure. Work is described in the following areas: CO oxidation on a Cu/Rh(100) Bimetallic catalysts; electronic properties of bimetallic surfaces; and reflection absorption spectroscopy of bimetallic surfaces. 5 figs. (CBS)

Wastenet

...Surface Aerators Products and Equipment Find and compare a variety of surface aerators products and equipment on the world's largest environmental industry portal. ...

International Nuclear Information System (INIS)

The paper presents experimental investigations of main features of plasma surface interaction and energy transfer to the material surface in dependence on plasma heat loads. The experiments were performed with QSPA repetitive plasma pulses of the duration of 0.25 ms and the energy density up to 2.5 MJ/m2. Surface morphology of the targets exposed to QSPA plasma screams is analyzed. Relative contribution of the Lorentz force and plasma pressure gradient to the resulting surface profile is discussed. development of cracking on the tungsten surface and swelling of the surface are found to be in strong dependence on initial temperature of the target.

Science.gov (United States)

In this paper we investigate the effects of surface mediation on the adsorption behavior of argon at different temperatures on homogeneous graphitized thermal carbon black and on heterogeneous nongraphitized carbon black surface. The grand canonical Monte Carlo (GCMC) simulation is used to study the adsorption, and its performance is tested against a number of experimental data on graphitized thermal carbon black (which is known to be highly homogeneous) that are available in the literature. The surface-mediation effect is shown to be essential in the correct description of the adsorption isotherm because without accounting for that effect the GCMC simulation results are always greater than the experimental data in the region where the monolayer is being completed. This is due to the overestimation of the fluid-fluid interaction between particles in the first layer close to the solid surface. It is the ...

Science.gov (United States)

A compact heat exchanger pedestal array for augmenting heat transfer in a machine is disclosed. The compact heat exchanger pedestal array includes a wall having first and second surfaces. The first surface faces a heated flow path and the second surface p...

Energy Technology Data Exchange (ETDEWEB)

In the present work, we describe application of binary pseudo-random gratings (BPRG) and arrays (BPRA) as effective 1D and 2D test surfaces suitable for calibration of different surface profilometers, including a number of interferometric microscopes and scatterometers.

Science.gov (United States)

Engine flow simulation was provided by four separately mounted air ejectors connected to a high-pressure air supply. The engine nacelle center lines were ...

International Nuclear Information System (INIS)

The variation of surface composition and sintering of the binary Pd_7Ag_3 nanoparticles prepared by chemical reduction were studied. The composition of the as-prepared Pd_7Ag_3 nanoparticles across the diameter is inhomogeneous due to different reduction potentials of Pd and Ag. Upon heating, Ag will migrate to the surface because of its lower surface energy. Surface modification results in variation of surface composition during the sintering process. Stearic acid acts as a grain growth inhibitor. The migration of Ag to the surface is suppressed and the sintering is retarded. Modification by polyethylene glycol leads to more migration of Ag atoms from the core to the surface. This makes the nanoparticles easier to sinter.

Science.gov (United States)

... GRIT-BLAST/SILANE (GBS) ... GRIT-BLAST/SILANE (GBS) ALUMINUM SURFACE PREPARATION FOR STRUCTURAL ADHESIVE BONDING 5b. ...

Science.gov (United States)

Infrared Thermometer: Ground surface temperature averaged 60-sec at 10-meter height

KoreaScience (Korea)

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KoreaScience (Korea)

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International Nuclear Information System (INIS)

Short communication.

Science.gov (United States)

... Other Sources Toxics Intranet Subsurface Injection of Liquid Waste -- Florida Surface features of a typical...

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a {gamma}-ray detector. It comprises: a dislocation-free single crystal having an input surface and a transmission surface at opposite ends thereof; an active shield surrounding the crystal and functioning as an anticoincidence counter; and {gamma}-ray detector means disposed adjacent the transmission surface of the crystal for receiving and detecting {gamma}-rays of a predetermined wavelength incident on the input surface of the crystal at a specific Bragg angle and transmitted through the crystal.

KoreaScience (Korea)

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

This report measured the rate of isothermal deposition of sub-micron particles of magnetite onto the surface of Alloy 800 at pH of 4.2-9.3 at Re=10,000 and a fluid temperature of 25C. Deposition is modelled as a two-step process, the transport of particles to the surface region followed by attachment to the surface.

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Not Available

International Nuclear Information System (INIS)

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

KoreaScience (Korea)

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British Library Electronic Table of Contents (United Kingdom)

Comparative patterns of equilibrium adsorption of argon on the surface of graphitized thermal carbon black (GCB) and the inhomogeneous surfaces of nongraphitized carbon black and silica at 77 and 87.3 K were considered. It was shown that argon acquires the properties of a special phase with a layered structure and exhibits two-dimensional phase transitions with the formation of crystal-like layers near the homogeneous surface of GCB even at a temperature exceeding the triple point. However, already at a distance of three-four molecular diameters from the surface, adsorbed argon behaves as a bulk phase in a weak external field. The defect surface of nongraphitized carbon black and the amorphous surface structure of silica destroy the longrange order of adsorbed argon and lower its solidific...

Science.gov (United States)

This invention is an improved solar energy cavity receiver for exposing materials and components to high temperatures. The receiver includes a housing having an internal reflective surface defining a cavity and having an inlet for admitting solar radiation thereto. A photothermal absorber is positioned in the cavity to receive radiation from the inlet. A reflective baffle is positioned between the absorber and the inlet to severely restrict the re-radiation of energy through the inlet. The front surface of the baffle defines a narrow annulus with the internal reflective surface of the housing. The front surface of the baffle is contoured to reflect incoming radiation onto the internal surface of the housing, from which it is reflected through the annulus and onto the front surface of the absorber. The back surface of the baffle intercepts ...

Energy Technology Data Exchange (ETDEWEB)

This invention is an improved solar energy cavity receiver for exposing materials and components to high temperatures. The receiver includes a housing having an internal reflective surface defining a cavity and having an inlet for admitting solar radiation thereto. A photothermal absorber is positiond in the cavity to receive radiation from the inlet. A reflective baffle is positioned between the absorber and the inlet to severely restrict the re-radiation of energy through the inlet. The front surface of the baffle defines a narrow annulus with the internal reflective surface of the housing. The front surface of the baffle is contoured to reflect incoming radiation onto the internal surface of the housing, from which it is reflected through the annulus and onto the front surface of the absorber. The back surface of the baffle intercepts ...

Energy Technology Data Exchange (ETDEWEB)

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

Energy Technology Data Exchange (ETDEWEB)

Excimer laser processing enables both thermally-driven transformations and the incorporation of solutes into the surface of materials through melting and diffusional mixing. We have examined the effect of excimer laser processing on the microstructure and surface mechanical properties of titanium alloys. Changes in the surface hardness due to laser processing were studied using a Nanoindenter [trademark]. Alloying experiments using both mixing of evaporated surface layers of boron and laser gas alloying in air and in nitrogen all result in changes in the surface hardness of the material. Alloying with boron results in an amorphous surface which is somewhat harder than the as polished surface. Laser processing in air and pure nitrogen results in incorporation of oxygen and nitrogen and the development of fine ([approximately] 50 nm) ...

British Library Electronic Table of Contents (United Kingdom)

There is investigated the role of polymer layers on the metal surface of a fine filler in the formation of a PVC system with electrophysical properties. It is shown that a physicochemical polymer modification takes place under the surface active center influence. Thus, the surface layer properties (density and geometrical characteristics) differ from the PVC ones. The correlation between the electrophysical properties of the PVC composite and the surface layer in the range of the fine copper fraction of 0?11.3 vol % at E ? 106 V m?1 and a frequency response of 20?2 ? 105 Hz is determined. An explanation of the investigated relation is presented.

Energy Technology Data Exchange (ETDEWEB)

The dispersion curves E(k-bar) have been calculated for bound and resonant (110) surface states of AlSb, AlAs, and AlP. AlSb is predicted to have no surface states within the bulk fundamental band gap, but AlAs and AlP are predicted to have surface state band minima which are very near the conduction band edge, and could lie either within the gap or immediately above the edge.

Energy Technology Data Exchange (ETDEWEB)

For quantitative acquisition of the influence of surface decarburizing phenomena on the failure of construction parts under cyclic stress different surface decarburization stages were generated in the steels 42CrMo4 and 100Cr6. After construction part-specific thermal treatment the generated states of residual stress were then determined and life span-oriented fatigue tests were conducted. The studies showed that already a small decarburization in martensitic material conditions of the steels 42CrMo4 and 100Cr6 led to a reduction of the alternating bending strength. The decrease of alternate strength can be associated with the micro-notch effects caused by the internal oxides formed by surface oxidation and/or the residual tension stress developed during the hardening in sub-surface sample areas. Decarburization degrees of more than 50% cause a noticeable decrease of surface ...

International Nuclear Information System (INIS)

The possibility of Pt-Cr surface alloys formation on Pt(0 0 1) was investigated and their magnetism was calculated by the full-potential linearized augmented plane wave (FLAPW) method with eight different atomic configurations. The most stable structure was calculated to be the Pt-segregated L1_2 ferromagnetic surface alloy. A_3B types (L1_2 or D0_2_2) were more stable compared to AB types (L1_0). It implies that the A_3B type surface alloys may be formed when depositing a monolayer of Cr on Pt(0 0 1). It was found from the total energy calculations that there exists a strong tendency of the Pt segregation. The segregation further stabilizes the surface alloy significantly. The work function of the most stable surface alloy was calculated to be 6.02 eV and the magnetic moment of the surface Cr was much enhanced to 3.3 #mu# _B. It is a quite interesting finding ...

International Nuclear Information System (INIS)

Surface energy of III-V semiconductors ended by (110) clean surface and surface covered by atomic monolayer of aluminium, copper and sulfur has been calculated. We have used the Greens-function technique based on the scheme of linear muffin-tin orbitals in the atomic sphere approximation (LMTO-ASA) for the crystal potential and width the local density approximation (LDA) for electrons. Two types of coverage are considered: full monolayer with two additional atoms per two-dimensional unit cell and half monolayer with one additional atom per unit cell. Full monolayer of metallic atoms increases the surface energy. Cu atoms lead to greater destabilization than Al atoms. Sulfur atoms stabilize (110) surface for all considered compounds. (author)

Energy Technology Data Exchange (ETDEWEB)

This patent describes a method of hydraulically mining a surface of a mining location comprising: a. determining the dimensions of the surface of the mining location from a fixed point at the location; b. constructing at a second location remote from the mining location a visual representation of the surface form the determined dimensions of the mining location with respect to the fixed point; c. jetting water under high pressure against a selected area on the surface of the mining location; d. determining changes in the dimensions of the selected area of the surface of the mining location; e. reconstructing at the second location a new visual representation of the surface from the determined changes of the location during the jetting of the water; and f. redirecting the jetted water under high pressure utilizing data from the reconstructed visual ...

British Library Electronic Table of Contents (United Kingdom)

Carbon black is widely used as an active filler in the rubber industry to improve the physical properties of rubber. The surface energy of carbon black is high compared to that of various elastomers like styrene?butadiene rubber (SBR), butadiene rubber (BR) and ethylene?propylene?diene rubber (EPDM). The work aims at reducing the surface energy of carbon black by modifying its surface for application especially in rubber blends. The present paper looks into the possibility of using plasma polymerisation of acetylene as a surface modification technique for carbon black in comparison with silica. Thermogravimetric analysis, wetting behaviour with various liquids of known surface tension and time of flight secondary ion mass spectrometry (ToF-SIMS) were used to characterise the carbon black b...

International Nuclear Information System (INIS)

Laser surface modification can lead to formation of a novel microstructure on the surface of a material resulting in improved surface properties. During the past one and half decades, a number of investigations have been reported on laser surface modification techniques for improving the corrosion resistance of various materials. This paper reviews various work reported on utilising laser modification techniques for enhancing the aqueous corrosion resistance of materials. The laser surface modification work carried out on materials like stainless steels, C-steels, low alloy steels and non-ferrous materials such as Zr, Zn, Al, Ni, Mg and their alloys has been covered in the review. General features observed in improving the corrosion resistance after laser processing have been discussed and scope for future investigations in this field has been highlighted. (author). 97 refs., 15 ...

British Library Electronic Table of Contents (United Kingdom)

To improve the friction and wear behavior of carbon fabric reinforced polymer composites (CFRP), nano-SiO2 was deposited on the fabric surface. The friction and wear behavior of the resulting composites were investigated on a model ring-on-block test rig. Experimental results revealed that fiber surface treatment contributed to largely improve the tribological properties of the CFRP composites. Scanning electron microscope (SEM) investigation showed that the worn surface of the surface modified CFRP composite was smoother under given load and sliding rate. Field emission scanning electron microscopy (FESEM), FTIR and X-ray photoelectron spectroscopy (XPS) studies of the carbon fiber surface showed that nanostructured Sio2 thin film can be obtained by SiO2 sols deposition, which improved th...

International Nuclear Information System (INIS)

The surface permeability of concrete walls and floors in houses was measured with a specially designed permeameter, based on measuring the air-flow induced by a pressure difference across a temporary test seal applied to a surface. The permeability of bulk concrete is 10"-"1"6 m"2. Areas free of surface defects had permeability ranging from 10"-"1"4 to 10-"1"6 m"2. However, surface defects are common on concrete wall surfaces, which increase the permeability to >10"-"1"2 m"2. This is too high for standard seal designs to be adequate as the only method of soil gas and radon exclusion. Satisfactory seals require either extended contact width or mechanical removal of the surface layer. (orig.). (2 figs., 1 tab.).

Energy Technology Data Exchange (ETDEWEB)

A simple model based on surface chemistry is developed, based an simple concepts of contact angle, wetting and spreading. Results of the modeling can be stated by two simplified ``rules of thumb``: (1) A liquid will spread on the surface of a solid if the surface tension of the liquid is lose than the surface free energy of the solid, and (2) The liquid having the surface tension nearest that of the solid will preferentially wet the surface of the solid. These two rules can then be used to define the parameters that constitute a process for formulating a plastic bonded explosive (PBX), which is a crystalline high-explosive material coated with a small amount of plastic polymeric material (the binder). The PBX then can be pressed to a high density, and machined to a specific shape. The pressed and machined explosive material can then be used in a physics ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Surface modification of topography and chemistry in order to achieve a specific water contact angle (CA) has been explored by using a novel combinatorial screening platform. The screening arrays consisted of 507 distinct combinations of micro-topographies and chemical compositions. By performing chemical modifications with 1H, 1H, 2H, 2H perfluoroethyltriethoxy-silane (PFS) and n-octadecyltriethoxysilane (ODS) on standard silicon wafers it was possible to include both superhydrophobic and very hydrophilic pad arrays in the same screening platform. Surfaces modified with PFS were more hydrophobic than surfaces modified with ODS, while the unmodified silicon surfaces were hydrophilic. For the PFS modified surfaces the largest CAs were achieved with a small pillar size of X-=-1-m and...

UK PubMed Central (United Kingdom)

A stiff skin forms on surface areas of a flat polydimethylsiloxane (PDMS) upon exposure to focused ion beam (FIB) leading to ordered surface wrinkles. By controlling the FIB fluence and area of exposure...Full Text Available

Science.gov (United States)

number Fax (501) 228-3600 (501) 228-3601 Surface Water Data Information Requests Bill Baldwin (501) 228-3602 Surface Water General Information Jaysson Funkhouser (501) 228-3663...

Science.gov (United States)

Comparative patterns of equilibrium adsorption of argon on the surface of graphitized thermal carbon black (GCB) and the inhomogeneous surfaces of nongraphitized carbon black and silica at 77 and 87.3 K were considered. It was shown that argon acquires the properties of a special phase with a layered structure and exhibits two-dimensional phase transitions with the formation of crystal-like layers near the homogeneous surface of GCB even at a temperature exceeding the triple point. However, already at a distance of three-four molecular diameters from the surface, adsorbed argon behaves as a bulk phase in a weak external field. The defect surface of nongraphitized carbon black and the amorphous surface structure of silica destroy the longrange order of adsorbed argon and lower its solidification temperature. Therefore, argon adsorbed at a temperature of 77 K, ...

UK PubMed Central (United Kingdom)

BackgroundSurface electromyography (sEMG) signals have been used in numerous studies for the classification of hand gestures and movements and successfully implemented in the position...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A survey is given of the influence of surface deformations on heavy ion reactions. Emphasis is put on the effect of zeropoint fluctuations in the entrance channel and on the effect on grazing collisions in terms of an imaginary part of the scattering potential.

International Nuclear Information System (INIS)

The radiation method has been employed for the modification of the surface of vascular prostheses by means of acrylamide. As a result of the treatment, the tightness of the prosthesis walls was improved as well as an increase of surface hydrophilicity. Upon autoclaving, stable binding of polyacrylamide to prostheses is achieved. (author).

Science.gov (United States)

This report results from a contract tasking Eindhoven University of Technology as follows: The contractor will investigate the plasma treatment of surfaces and plasma enhanced deposition using EUT's cascade arc source as the basis for this effort.

UK PubMed Central (United Kingdom)

We have developed miniature (≈1 μm diameter) microcavity surface-plasmon-resonance sensors (MSPRS), integrated them with microfluidics and tested...Full Text Available

International Nuclear Information System (INIS)

The methods of surface modification of Ti-Zr alloy by laser treatment are considered. Characteristics of laser modification without- and with surface melting and with melting in different gaseous environments and with nickel microalloying are presented. Maximum depth, hardness and corrosion resistance are observed under nickel laser alloying.

UK PubMed Central (United Kingdom)

The interior of 237 nm spherical vinylsilsesquioxane nanoparticles has been covalently modified and their surface functionalized under mild conditions to yield a novel type of hybrid silsesquioxane...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Industrial applications of thermoplastic polymers are often limited by their poor adhesion properties. In this work the effect of surface oxyfluorination on the adhesion properties was investigated for polyethylene (PE), polyoxymethylene (POM), polybutylene terephthalate (PBT) and polyamide 6 (PA6). The adhesive joint strength was quantified using lap-shear tests. These results were correlated with the changes in the chemical composition of the surface, determined by X-ray photoelectron spectroscopy (XPS), in the surface free energy, measured by the contact angle method, and in the topography, using white-light confocal microscopy. The adhesive strength is strongly improved for all four polymers, but the degree of this increase depends on the polymer type. The surface free energy shows a similar trend for all four polymers. A high surface free energy exceeding 50 mN/m was observed ...

UK PubMed Central (United Kingdom)

It has been postulated that thrombin binds to endothelial cells through, at least in part, cell surface glycosaminoglycans such as heparan sulfate, which could serve as antithrombin cofactor on the...Full Text Available

UK PubMed Central (United Kingdom)

Plant surfaces covered with crystalline epicuticular waxes are known to be anti-adhesive, hardly wettable and preventing insect attachment. But there are insects that are capable of gluing their eggs...Full Text Available

UK PubMed Central (United Kingdom)

We study how the microscale topography of a solid surface affects the apparent advancing and receding angles at the contact line of a liquid drop pinned to this surface. Photolithographic methods...Full Text Available

UK PubMed Central (United Kingdom)

The opportunistic pathogenic yeast Candida albicans exhibits growth phase-dependent changes in cell surface hydrophobicity, which has been correlated with adhesion to host tissues....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

In this paper the authors prove a uniqueness theorem for the electric detection of cavities in a three dimensional solid from Cauchy data measured on the surface. The cavities, finite in number, are assumed to be insulating. The surfaces of the cavities are assumed to be smooth on the complement of a set that is, in some sense, negligible. (orig.)

UK PubMed Central (United Kingdom)

Functionalizing of single molecules on surfaces has manifested great potential for bottom-up construction of complex devices on a molecular scale. We discuss the growth mechanism for the initial layers...Full Text Available

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Ultrasonic enhancement of heat transfer on a narrow surface was measured by changing the width of the surface from 8 to 0.1 mm. Ultrasonic power of 600 W with a frequency of 40 kHz was used. Heat transfer on the narrow surface without ultrasonic vibration was correlated by the experimental equation for a thin wire. The cavitation intensity was measured by the cavitation erosion loss of an aluminum foil of 15 [mu]m thickness. The effects of acoustic streaming and cavitation were separated by this measurement. Heat transfer by acoustic streaming was predicted through forced convection. Enhancement by cavitation was explained by the turbulence thermal conductivity of the microjets.

Energy Technology Data Exchange (ETDEWEB)

A high pressure waterjet has been used to study the surface roughening of superalloys as preparation for thermal spraying. Designed experiments for Mar-M 509 and Rene 80 were carried out for the effects of jet pressure and mass of water delivered per unit area. Comparisons were made of several superalloys in terms of erosion, surface roughness and topology. The mechanism of jet erosion of Rene 80 was studied in relation to its metallurgical microstructure. An MCrAlY coating by shrouded plasma spray was made over a waterjet prepared surface with excellent bonding and having an ideally clean interface.

KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

... Abstract : The acousto-optic filter (AOF) is ... for large switch networks. ... FOURIER TRANSFORMATION, OPTICAL SWITCHING, SURFACE ACOUSTIC ...

KoreaScience (Korea)

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Science.gov (United States)

... interactive surfaces and interfaces, and 3) the more complex a ... carbonate or calcium phosphate with a thin interface ... diameter) for nerve prosthesis. ...

KoreaScience (Korea)

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

We present a numerical method for computing diffusive transport on a surface derived from image data. Our underlying discretization method uses a Cartesian grid embedded boundary method for computing the volume transport in region consisting of all points a small distance from the surface. We obtain a representation of this region from image data using a front propagation computation based on level set methods for solving the Hamilton-Jacobi and eikonal equations. We demonstrate that the method is second-order accurate in space and time, and is capable of computing solutions on complex surface geometries obtained from image data of cells.

International Nuclear Information System (INIS)

Nano-materials in which a large fraction of atoms resides within a few atomic layers near the surface can be designed to have novel properties by manipulating their surface parameters. We show that the effective elastic constants of nano-porous/cellular materials can be made to exceed those of the parent materials provided the pore surface elastic parameters satisfy certain conditions. These stiff nano-porous materials herald a radical breakthrough in sandwich-type construction.

KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

The surface composition and composition near the surface and properties of high-silica zeolites of the TsVK-1 type were studied by XPES, IRS, and low-temperature adsorption of N/sub 2/. It was found that changing the sequence of operations during preparation of the H form of the zeolites results in a different set of acid centers on their surface, caused by migration of cations into the bulk of the zeolites. Migration of elements is also observed during the catalytic reaction of conversion of ethanol.

KoreaScience (Korea)

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Science.gov (United States)

... solid particle contamination. Solid particulate impact is a good mechanism for surface heat transfer augmentation. The aug ...

Energy Technology Data Exchange (ETDEWEB)

The state of lithium electrode surface after contact with triethylamine-modified propylene carbonate solutions of lithium perchlorate was studied using the pulse galvanostatic technique as well as methods of SIMS and electron microscopy. It was shown that amine added into the solutions stabilizes the state of lithium and prevents the formation of a secondary porous passive film on the lithium surface. Chemical composition of the primary film remains unchanged. Certain properties of passive films formed in electrolyte solutions studied were evaluated.

Energy Technology Data Exchange (ETDEWEB)

Although silicosis has been studied extensively, the mechanism is still not fully understood. Experiments do provide evidence that the actions of unique properties of silica surface on the cell membrane are the starting point of silicotic processes. This paper summarizes literature on chemical properties of silica surface, and the effect of particle size on silica toxicity. This paper also discusses the ways in which silica dusts are though to interact with the cell membrane, with emphasis on freshness, hydrogen bonding, and free-radical interactions.

International Nuclear Information System (INIS)

Full text: The surface properties of poly (tetrafluoroethylene) (PTFE) are changed by the exposure to synchrotron radiation (SR). We succeeded in controlling the wettability of the PTFE surface from hydrophobic to hydrophilic by varying the substrate temperature during the SR irradiation and found that the wettability was ascribable to microstructure and chemical composition of surface.In these previous works, oxygen atoms were found to inhabit on the hydrophobic surface of PTFE. In this study, we investigated the surface modification of PTFE from the SR exposure experiment under the O_2 gas atmosphere. The SR exposure to the PTFE sheet was carried out at beamline 6 (BL6) of the New- SUBARU. The PTFE sheet was irradiated to the white beam, ranging 50-1000 eV at BL6 at room temperature. The gas cell was mounted at the irradiation chamber. The O_2 gas pressure in the gas cell can be ...

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Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.

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We propose a generalization of the character formulas of the SU(2) Kac-Moody algebra to higher genus Riemann surfaces. With this construction, we show that the modular invariant partition funciton of the SO(4) k = 1 Wess-Zumino model is equivalent, in arbitrary genus Riemann surfaces, to that of free fermion theory.

Energy Technology Data Exchange (ETDEWEB)

Climates at regional scale are strongly dependent on the interaction between atmosphere and its lower boundary, the oceans and the land surface mosaic. Land surfaces influence climate through their albedo, and the aerodynamic roughness, the processes of the biosphere and many soil hydrological properties; all these factors vary considerably geographically. Land surfaces receive a certain portion of the solar irradiance depending on the cloudiness, atmospheric transparency and surface albedo. Short-wave solar irradiance is the source of the heat energy exchange at the earth`s surface and also regulates many biological processes, e.g. photosynthesis. Methods for estimating solar irradiance, atmospheric transparency and surface albedo were reviewed during the course of this project. The solar energy at earth`s surface is consumed for heating ...

International Nuclear Information System (INIS)

The IGC-30 HPGe detector with MCA 'CANBERRA-10 PLUS' allows to determine surface contamination of areas of any type with a minimum error in radius 8-10 m, at a 'uniform' contamination. A modification of the CANBERRA hardware and software is described allowing determination of both the activity of a possible 'radioactive spot' and the activity of the whole observed surface. (author).

Energy Technology Data Exchange (ETDEWEB)

The fundamental ionisation process of negative surface ionisation is described and two applications are discussed. One is in the so called surface-plasma sources which enable the production of intense negative ion beams. The second application is in the passive diagnosis of the charge exchange of neutrals emitted from hydrogen plasmas.

Energy Technology Data Exchange (ETDEWEB)

A spherical-geometry, self-extraction negative ion source has been designed and fabricated. The source utilizes direct surface ionization to form negative ion beams resulting from interactions between high electron affinity gaseous elemental or molecular materials and a negatively biased, spherical-sector LaB{sub 6} surface ionizer maintained at {similar to}1300 K. The design features of this source and principles upon which the source is based are discussed in this report.

British Library Electronic Table of Contents (United Kingdom)

A mission to the surface of Venus would have high scientific value, but most electronic devices and sensors cannot operate at the 450degreeC ambient surface temperature of Venus. Power and cooling systems were analyzed for Venus surface operation. A radioisotope power and cooling system was designed to provide electrical power for a probe operating on the surface of Venus. For a mission duration of substantial length, the use of thermal mass to maintain an operable temperature range is likely impractical, and active refrigeration may be required to keep components at a temperature below ambient. Due to the high thermal convection of the high-density atmosphere, the heat rejection temperature was assumed to be at a 500degreeC radiator temperature, 50degreeC above ambient. The radioisotope S...

British Library Electronic Table of Contents (United Kingdom)

Plastic injection molds are an important economic sector due to the increasing use of injection molded plastic components. The selection of mold steel material, its processing conditions, and the way it is machined and hardened all have an impact on how it performs during use across its lifecycle for injection molding. For this study, injection molding conditions seen during high volume manufacturing were used to induce wear that would be typical during processing. A 50wt.% glass fiber reinforced Polybutylene Terephthalate (PBT) was used for the research. After 3000 injection operations, surface damage was found only on the steel used for the stationary half of the mold cavity and the corresponding surface of the molded parts. In contrast, the moving half showed no surface damage or increa...

International Nuclear Information System (INIS)

Soil placed over any sealant/barrier system can provide a protective mantle if the soil is not lost by erosion. Vegetation is an attractive choice for controlling erosion because it can provide an economic self-renewing cover that serves to reduce erosion by both wind and water. Vegetation alone, however, may not adequately stabilize the surface in extremely arid areas. In those areas, a properly designed surface treatment of rock cover, perhaps in conjunction with vegetation, may be necessary to stabilize the tailings surfaces. The objective of this program is to establish guidelines for surface stabilization that are compatible with sealant/barrier systems and that are suited to soils and climates at inactive uranium mill tailings sites. These guidelines will provide the means to estimate potential vegetation cover, potential erosion, effects of surface treatments on ...

British Library Electronic Table of Contents (United Kingdom)

We investigated the use of Surface Free Energy (SFE) measurements, describing coherence between surfaces of two solids, in evaluation of affinity between skin surface and foundation, a possible predictor of makeup longevity. We found that the gp values of skin varied significantly among subjects. After discovering that the SFE values of most available conventional foundation products were very different from that of skin, specially formulated experimental foundations with SFE values close to that of the skin surface were prepared using conventional powder ingredients and novel powder ingredients coated with polyethylene glycol. In our usage tests, the SFE-controlled foundations demonstrated superior performance to that of conventional foundations and most of subjects preferred the SFE-cont...

CERN Document Server

The confining effect of a spherical substrate inducing anchoring (normal to the surface) of rod-like liquid crystal molecules contained in a thin film spread over it has been investigated with regard to possible changes in the nature of the isotropic-to-nematic phase transition as the sample is cooled. The focus of these Monte Carlo simulations is to study the competing effects of the homeotropic anchoring due to the surface inducing orientational ordering in the radial direction and the inherent uniaxial order promoted by the intermolecular interactions. By adopting entropic sampling procedure, we could investigate this transition with a high temperature precision, and we studied the effect of the surface anchoring strength on the phase diagram for a specifically chosen geometry. We find that there is a threshold anchoring strength of the surface below which uniaxial nematic phase results, and above ...

International Nuclear Information System (INIS)

A Gross Decontamination Experiment was conducted on various levels and surfaces of the TMI - Unit 2 reactor building in March 1982. The polar crane, D-rings, missile shields, refueling canals, refueling bridges, equipment, and elevations 305' and 347'-6'' were flushed with low pressure water. Additionally, floor surfaces on elevation 305' and floor surfaces and major pieces of equipment on elevation 347'-6'' were sprayed with high pressure water. Selective surfaces were decontaminated with a mechanical scrubber and chemicals. Strippable coating was tested and evaluated on equipment and floor surfaces. The effectiveness, efficiency, and safety of several decontamination techniques were established for the large, complex decontamination effort. Various decontamination equipment was evaluated and its effectiveness was documented. Decontamination training and procedures were documented ...

Energy Technology Data Exchange (ETDEWEB)

The use of dendrimers for preparing chemically sensitive interfaces for detecting volatile organic compounds (VOCs) using surface acoustic wave (SAW) device transducers is described. Specifically, the synthesis of the dendrimers and the means by which they are affixed to SAW devices is discussed, followed by a detailed spectroscopic analysis of the surface-confined dendrimers and a discussion of their interaction with different VOCs. Most of these preliminary experiments focus on dendrimer surface modification using benzoylchloride, which leads to phenyl terminal groups linked to the dendrimer via amide groups. The results of this study lead us to conclude that dendrimers: (1) provide general specificity towards classes of functional groups and are therefore suitable for array-based sensing schemes; (2) are intermediate in structure between monolayers and polymers and exhibit the desirable properties of both; (3) can be ...

International Nuclear Information System (INIS)

Experiments on the depth dependence of transient enhanced diffusion (TED) of boron during rapid thermal annealing of Ge-preamorphized layers reveal a linear decrease in the diffusion enhancement between the end-of-range (EOR) defect band and the surface. This behavior, which indicates a quasi-steady-state distribution of excess interstitials, emitted from the EOR band and absorbed at the surface, is observed for annealing times as short as 1 s at 900 deg. C. Using an etching procedure we vary the distance x_E_O_R from the EOR band to the surface in the range 80-175 nm, and observe how this influences the interstitial supersaturation, s(x). The supersaturations at the EOR band and the surface remain unchanged, while the gradient ds/dx, and thus the flux to the surface, varies inversely with x_E_O_R. This confirms the validity of earlier modelling of EOR defect evolution in terms of ...

Energy Technology Data Exchange (ETDEWEB)

By using a plasma nitriding procedure at the PUPR Mirror Cusp Plasma machine, surface hardness is increased in 302/304-type stainless steel samples by exposing them to high-ion-density plasma at high vacuum. This method successfully dopes the surface of the material with strengthening nitrogen ions, without the use of chemical procedures that sacrifice the resistance to corrosion of the given material. A 500 V negative bias is placed on the sample exposed to the nitrogen plasma, where high-energy ions are therefore attracted and immersed into the metallic matrix microns into the surface of the stainless steel. This potential maintains a constant surface temperature at approximately 800 deg. C. The plasma parameters including ion density and plasma temperature were diagnosed using single Langmuir probes. The stainless steel samples were then tested using scanning electron microscopy (SEM), and Vickers ...

International Nuclear Information System (INIS)

The Gross Decontamination Experiment was conducted on various levels and surfaces of the TMI-2 Reactor Building during February and March 1982 and was designed to investigate the effectiveness of various surface decontamination techniques. The polar crane, D-rings, missile shields, refueling canal, fueling bridge, major equipment, floors and some walls were flushed with low pressure water. Water lances were directed manually and applied water at temperatures between ambient and 60"0C at a flow rate of about 95 liters per minute. In addition, floor surfaces on the 305-ft elevation and floor surfaces and major equipment on the 347-ft elevation were sprayed with high pressure water (floors in the Reactor Building are designated by their elevations above sea level). The water pressure in this case varied between 13.8 and 41.4 mPa and water temperature was at a maximum 60"0C. Certain ...

Energy Technology Data Exchange (ETDEWEB)

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

Science.gov (United States)

Target vessel materials used in spallation neutron source will be exposed to proton and neutron irradiation and mercury immersion environments. In order to evaluate the surface degradation of the vessel candidate materials due to such environment, the triple-ion beam irradiation taking the spallation reaction into account and mercury immersion tests were carried out. Mechanical properties of the gradient surface layer were evaluated by the inverse analysis with multi-layer model that considers distribution of surface characteristic was applied to the load and depth curves measured by using the instrumented indentation machine. Transmission electron microscopic observations were performed to evaluate the changes of microstructure in irradiated surface layer using focused ion-beam cut micro-specimen. The mechanical properties distributions in the surface layer were evaluated ...

International Nuclear Information System (INIS)

The 2-step low temperature plasma processes (the combined carburizing and post-nitriding) were carried out for improving both the surface hardness and corrosion resistance of AISI 316L stainless steel. The effects of processing time and temperature on the surface properties during nitriding step were investigated. The expanded austenite (#gamma#N)was formed on all of the treated surface. The thickness of #gamma#N was increased up to about 20 #mu#m and the thickness of entire hardened layer was determined to be about 40 #mu#m. The surface hardness reached up to 1,200 HV_0_._1 which is about 5 times higher than that of untreated sample (250 HV_0_._1). The thickness of #gamma#N and concentration of N on the surface were increased with increasing processing time and temperature. The corrosion resistance in 2-step low temperature plasma processed austenitic stainless steels was enhanced ...

International Nuclear Information System (INIS)

Sealants for radon-resistant foundation construction must seal the gap between concrete sections. Modern sealants have such low permeability that seal performance depends only on the permeability of the material that contacts the sealant. The surface permeability of concrete walls and floors was measured by a specially designed permeameter, which measures the airflow induced by a pressure difference across a temporary test seal applied to the surface. The permeability of bulk concrete is about 10"-"1"5 m"2. Areas free of surface defects had surface permeability ranging from 10"-"1"4 to 10"-"1"6 m"2. However, surface defects are common on concrete wall surfaces, which increase the permeability to >10"-"1"2 m"2, too high for standard seal designs to be adequate as the only method of soil gas and radon exclusion. Radon-resistant seals require either extended ...

Energy Technology Data Exchange (ETDEWEB)

A number of properties in steel components are detrimentally influenced when exposed to hydrogen environments. Under these conditions, atomic hydrogen is adsorbed on the steel surface, then absorbed and preferentially transported towards tri-dimensional stressed regions in the crystal lattice and into defects such as interfaces or dislocations. The hydrogen embrittlement susceptibility is strongly influenced by various microstructural parameters including the type of inclusions, steel composition and heat treating conditions. One of the alternatives employed in minimizing hydrogen embrittlement is the use of surface barriers for hydrogen permeation. In particular, the presence of surface nitride layers in steels can be considered as an effective barrier. Nitride steel surface layers can be produced by plasma nitriding with the concomitant benefits of improved surface hardness, as ...

Energy Technology Data Exchange (ETDEWEB)

In addition to ceramics, alloys such as tool steel and nickel- and iron-based superalloys are being considered for high temperature applications such as missile bearings and low heat rejection engines. Studies were made to lubricate a nickel-based superalloy at 500{degrees}C, by using a vaporized aryl phosphate ester, at a concentration of 0.1% in air. From deposition and wear studies it was found that it was impossible to form a good polymeric coating on the superalloy surface. Energy dispersive X-ray analyzer (EDXA) analysis showed that this was due to minute quantities of aluminum in the alloy segregating to the surface, upon being heated to 500{degrees}C, forming a passive oxide coating. It was necessary to activate the surface, in order to lubricate the material successfully. A method of activation by electrodepositing the surface with a layer of iron oxide was developed. Once activated, a good ...

Science.gov (United States)

The contents of this report covers: (1) development of optimal geometries for crowned helical gears; (2) a method for their generation; (3) tooth contact analysis (TCA) computer programs for the analysis of meshing and bearing contact of the crowned helical gears; and (4) modelling and simulation of gear shaft deflection. The developed method for synthesis was used to determine the optimal geometry for a crowned helical pinion surface and was directed to localize the bearing contact and guarantee favorable shape and a low level of transmission errors. Two new methods for generation of the crowned helical pinion surface are proposed. One is based on the application of a tool with a surface of revolution that slightly deviates from a regular cone surface. The tool can be used as a grinding wheel or as a shaver. The other is based on a crowning pinion tooth surface with predesigned ...

Energy Technology Data Exchange (ETDEWEB)

The relationship between the gas to melt ratio (GMR) and the surface temperature of an evolving billet surface in spray forming is investigated numerically. The basis for the analysis is an integrated approach for modelling the entire spray forming process. This model includes the droplet atomization taking thermal coupling into consideration and the deposition of material at the surface of the billet taking geometrical aspects such as shading into account. The coupling between these two models is accomplished by ensuring that the total droplet size distribution of the spray is the summation of ''local'' droplet size distributions along the r-axis of the spray cone. The criterion for a successful process has been a predefined process window characterised by a desired fraction solid range at a certain distance from the atomizer. Inside this process window, the gas and melt flows have been ...

Energy Technology Data Exchange (ETDEWEB)

Mechanisms that govern transport, accumulation and toxicity of persistent pollutants at interfaces in aquatic ecosystems were the foci of this thesis. Specific attention was paid to humic substances, their occurrence, composition, and role in exchange processes across interfaces. It was concluded that: The composition of humic substances in aquatic surface microlayers is different from that of the subsurface water and terrestrial humic matter. Levels of dissolved organic carbon (DOC) in the aquatic surface microlayer reflect the DOC levels in the subsurface water. While the levels and enrichment of DOC in the microlayer generally show small variations, the levels and enrichment of particulate organic carbon (POC) vary to a great extent. Similarities exist between aquatic surface films, artificial semi-permeable and biological membranes regarding their structure and functioning. Acidification and liming of freshwater ...

International Nuclear Information System (INIS)

Samples prepared using the focused ion beam (FIB) inevitably contain the surface damage induced by energetic Ga"+ ions. An effective method of removing the surface damage is demonstrated using a plasma cleaner, a device which is widely used to minimize the surface contamination in scanning transmission electron microscopy (STEM). Surface bombardment with low-energy Ar"+ ions was induced by biasing the sample immersed in the plasma source, so as to etch off the surface materials. The etch rates of SiO_2, measured with a bias voltage of 100-300 V, were found to vary linearly with both the time and bias and were able to be controlled from 1.4 to 9 nm/min. The removal of the Ga residue was confirmed using energy dispersive spectroscopy (EDS) after the plasma processing of the FIB-prepared sample. When the FIB-prepared sample was processed via plasma etching for 10 min with a bias of 150 ...

International Nuclear Information System (INIS)

Kinetic Monte Carlo simulations are used to analyze the ripening and dissolution of small Si interstitial clusters and #left brace#113#right brace# defects, and its influence on transient enhanced diffusion of dopants in silicon. The evolution of Si interstitial defects is studied in terms of the probabilities of emitted Si interstitials being recaptured by other defects or in turn being annihilated at the surface. These two probabilities are related to the average distance among defects and their distance to the surface, respectively. During the initial stages of the defect ripening, when the defect concentration is high enough and the distance among them is small, Si interstitials are mostly exchanged among defects with a minimal loss of them to the surface. Only when defects grow to large sizes and their concentration decreases, the loss of Si interstitials through diffusion to the surface prevails, ...

Energy Technology Data Exchange (ETDEWEB)

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

International Nuclear Information System (INIS)

A series of ball-on-disc wear and friction measurements were made for surfaces which have a chemical vapour deposition carbon silicon alloy layer on a carbon substrate (fine grain POCO graphite). Nitrogen ion irradiation was used to improve the wear resistance of the carbon alloy surface. For comparison, measurements were also taken for alumina against alumina. It was found that the lowest friction coefficient and lowest wear occurred for ion irradiated coated samples containing 4% Si in the alloy and that the performance was superior to that of alumina. ((orig.)).

Energy Technology Data Exchange (ETDEWEB)

The properties of a helium film on the surface of solid parahydrogen are investigated. It is shown that wetting of the solid hydrogen by the liquid helium occurs. The transport velocities along the He II film on the solid parahydrogen surface are measured in broad temperature, film height, and level difference ranges. It is shown that the transport velocity in this case has the least value as compared with its value on other substrates. The thickness of the helium-saturated film is determined on the solid hydrogen surface on the basis of the data obtained, and the value is in good agreement with the results of a computation performed within the framework of the Frenkel' theory.

International Nuclear Information System (INIS)

The early work of Stern has been reviewed briefly along with some of our experiments carried out later with similar geometrical arrangements in order to highlight his successes at the time and the future developments of his findings and predictions. The double crystal technique, developed by Stern has been used for energy analysis of He beams and results are shown for scattering from a rough reconstructed (001) InSb surface and Xe adsorbed layers. Surface phonons were not observed in the case of InSb probably as a result of the rough surface. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The chemical properties of alloys in a given environment are to a large extent governed by the surface composition. Changes of the surface composition during passivation are important features in this respect. Previous studies of single crystal Ni-Mo alloys surfaces have been reported. The aim of this work was to obtain quantitative data, for the natural oxide and the passive films formed on Ni-6% Mo(100) and (110) alloys, using Rutherford backscattering spectroscopy and nuclear reaction analysis.

Energy Technology Data Exchange (ETDEWEB)

The applications of neutron reflectometry to study dynamic phenomena at surface and interfaces have been restricted so far. This was mainly due to the low intensity of neutron sources, but now high-intensity spallation neutron sources are under construction in Japan (J-PARC) and US (SNS). We are planning to install a spin-echo option on the J-PARC neutron reflectometer with horizontal sample geometry for studies of dynamics of surfaces and interfaces. This option is based on the resonance spin-echo method and aimed at dynamics up to hundreds of nanoseconds. In this contribution, the plan and status of development are introduced together with the principle and characteristics of this option.

Energy Technology Data Exchange (ETDEWEB)

Preliminary results of studies into penetrant testing at high surface temperature (up to 200 deg.C), are presented. Tests were performed to assess the effectiveness of red dye penetrants using Al and NiCr samples containing artificial as well as natural discontinuities. The test results will be used in due course to formulate a specification for non-destructive testing procedure qualification at non-standard (i.e. outside 16-52 deg.C) temperatures.

Energy Technology Data Exchange (ETDEWEB)

In situ Auger sputter depth profiles of saturation implants of 3 keV N/sub 2//sup +/ in silicon at room temperature exhibit a sharp peak in the nitrogen concentration in the outermost layers, followed by a monotonic decrease. No broad plateau was observed. The energy of the Auger line corresponding to the Si(2p) core electron excitation, monitored throughout the profiling, exhibits a chemical shift of up to 7 eV at the surface peak concentration. Inert gas ion post-bombardment of unsaturated implants significantly modifies the profile, and supports the suggestion that the surface peak arises through radiation enhanced diffusion of implanted atoms.

Energy Technology Data Exchange (ETDEWEB)

Silicon nitride hybrid ball bearings used in high temperature applications undergo mechanical and environmental degradation. To study the surface chemistry of silicon nitride, a CAChe{trademark} Worksystem* has been used to generate the clusters and corresponding transmission vibrational spectra of silicon nitride. In the present study, the effect of surface conditions on the surface chemistry and wear degradation of silicon nitride was evaluated. Infrared reflection spectroscopy (IRRS) used to determine molecular orientations shows a difference in reflectance spectra for fractured and as-received.

International Nuclear Information System (INIS)

Glow discharge plasma nitriding of AISI 304 austenitic stainless steel has been carried out for different processing time under optimum discharge conditions established by spectroscopic analysis. The treated samples were analysed by X-ray diffraction (XRD) to explore the changes induced in the crystallographic structure. The XRD pattern confirmed the formation of an expanded austenite phase (#gamma#_N) owing to incorporation of nitrogen as an interstitial solid solution in the iron lattice. A Vickers microhardness tester was used to evaluate the surface hardness as a function of indentation depth (#mu#m). The results showed clear evidence of surface changes with substantial increase in surface hardness.

Energy Technology Data Exchange (ETDEWEB)

A full scale experiment was carried out to investigate the texture characteristics of the falling water of free falling and slope failing types. According to the increase of Reynolds number, the texture of falling water was classified into three categories for both types: stability of free surface, transition and whole turbulence. In the first category the stability of the free surface was related to the growth of minute disturbance. Surface tension works as a counter, force to the disturbance in free falling water, and gravity in slope falling water. 14 refs., 15 figs., 3 tabs.

International Nuclear Information System (INIS)

Effect of scale on determination of 12Kh18N10T steel tendency to intergranular corrosion (IGC) by rapid electrochemical techniques in solution of 10 % H_2SO_4+0.0025 g/l KCNS was investigated. It is shown that scale presence of steel surface accelerates anode dissolving, activates grain boundaries. All this results to the effect of tendency to IGC in steels, not inclined to it. The scale is not completely removed from the surface, but remains partially along grain boundaries in result of successive pickling of scale and then a surface layer of metal. This also couses the effect of tendency to IGC.

Energy Technology Data Exchange (ETDEWEB)

In an ideal system the surface of the dish is perfectly parabolic (no contour flaws are present), and the sun rays fall on the dish surface parallel to the focal axis (no sun tracking flaws are present). These two conditions are not realizable in practice; in this case, the parabolic dish system is called real system. In this paper a procedure for analysing the flux distribution on the receiver internal surfaces is presented for a cavity receiver with a real parabolic dish collector. First, the theoretical principles are discussed. Then the effect of the inaccuracy in the collector and in the sun tracking on the insolation pattern is described using an example.

Energy Technology Data Exchange (ETDEWEB)

In this work, the chemical transformations induced by 5 keV protons (10{sup 6} ion cm{sup -2}) at the surface of 0.4 {mu}m polyacrylonitrile and polymethacrylonitrile films are analysed by XPS and IRRAS. Spectroscopic changes in both the polymers are globally similar, the most significant feature being a lower relative concentration of nitrogen with respect to carbon closer to the surface. Quantitatively, this change is more marked in the case of polyacrylonitrile which suggests a direct relation with the hydrogen in {alpha} to the nitrile function.

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In modern quality engineering, dual response surface methodology is a powerful tool to model an industrial process by using both the mean and the standard deviation of the measurements as the responses. The least squares method in regression is often used to estimate the coefficients in the mean and standard deviation models, and various decision criteria are proposed by researchers to find the optimal conditions. Based on the inherent hierarchical structure of the dual response problems, we propose a Bayesian hierarchical approach to model dual response surfaces. Such an approach is compared with two frequentist least squares methods by using two real data sets and simulated data.

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How to decide which mine surface tasks may be performed by industrial robots to improve productivity and working conditions is described. Charts are presented of the industrial tasks performed on the surface and how each task may be classified as light, average, difficult or very diffcult according to a defect criteria is explained (defective operations are those which involve, heavy, harmful, stressful or dangerous jobs). The results of these calculations are used to identify which operations are suitable for first introduction of robots since traditional automation methods cannot be used, e.g. various storage, loading and packaging tasks, coal selection, sorting and removal of foreign matter, provision of services such as food preparation, cleaning, etc. Robots may also be used to control automated operations that are monotonous and hazardous for human operators. It is envisaged that in the future computer programmed robots with artificial ...

International Nuclear Information System (INIS)

In this paper, the influence of plasma nitriding at temperature 720 deg. C for 20 h on the surface microstructure and interface microstructure of electroplated chromium coating was investigated. In these conditions, interdiffusion, mixing and reaction phenomena of elements originating from the substrate and coating material are more likely to occur, thus increasing the bonding strength between the coating and carbon steel substrate. The change of the structures from the substrate side to the coating surface, and the effect of the substrate steel on the interface structure were studied by cross-sectional transmission electron microscope observation (XTEM). The nitride layer formed on the surface was analyzed by X-ray diffraction method (XRD). After treatment at above conditions a 6-7 #mu#m thick nitride compound layer was formed in surface region and the same thick carbide compound layer was also formed ...

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The properties of AlN make this material very attractive for optical, electronic, and tribological application. Also, if the AlN could be formed on the Al surface to enhance its surface properties, Al could be applied for the lightening of machine parts. However, a dense oxide film exists on the surface of Al, which prevents the formation of the Al nitride even during plasma nitriding and plasma coating process. In this study, plasma nitriding has been tried to form an AlN layer on Al after the surface activation processes. During the plasma nitriding, the density of the nitrogen ions was amplified by means of controlling the power of the Al substrates. The film thickness, microstructural features and the mechanical properties such as hardness and wear properties of the AlN layer were examined as a function of the process parameters of pretreatment and plasma nitriding

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This work is focused on effect of various cooling strategies on surface roughness and tool wear during computer aided milling of soft workpiece materials. These milling operations were selected as dry milling, cool air cooling milling and fluid cooling milling. A cool air cooling system was designed and produced to cool end milling tools. Cool air was produced by a vortex tube. Annealed AISI 1050 was used as the workpiece material and cutting tool material was selected as HSS-Co8 DIN 844/BN. Optimal cutting parameters were selected according to workpiece hardness from reference catalog and kept for all tests. Tool wear and surface quality were measured for three different cooling types changing from ten minute machining time to thirty minute machining time. As a result, the surface roughne...

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Low-cost fabrication of PMC composite sandwich panels, including metallic surface preparations for bonding the PMC to titanium honeycomb. ...

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A new technique has been developed for improving corrosion resistance on magnesium alloys. Specimens of AZ31 magnesium alloy were dipped into molten salt of NaBF{sub 4} at 723 K for various times, and then cooled, rinsed with water, and dried in air. Corrosion resistance in the surface treated specimens was evaluated by salt immersion test using 1% NaCl solution as a time for occurring filiform corrosion. On an un-treated AZ31 alloy, the time for starting the filiform corrosion was about 1.2 ks, while on the surface treated specimen, the time was prolonged into about 1300 ks. Moreover, the surface treated specimen showed corrosion resistance in low pH solutions, such as 1% HNO{sub 3} and HCl solutions. (orig.)

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... Sergio Department of Materials, University of Oxford, Oxford (United Kingdom)

International Nuclear Information System (INIS)

2009 p. 200-201 Ukraine Glushkov, AV Odesa State Environmental

UK PubMed Central (United Kingdom)

Conditions were found in which Chlamydomonas reinhardi exhibits a circadian alteration of its cell surface, measured as ability to stick to glass. Under these same conditions the cells...Full Text Available

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We report the simultaneous formation of self-assembled surface ripples in Cd{sub 2}Nb{sub 2}O{sub 7} pyrochlore caused by focused ion beam (FIB) patterning and uniformly distributed metallic nanodots induced by phase decomposition under ion bombardment. The characteristic wavelength of the surface ripples is controllable from the nm to the sub-{micro}m scale. High-density Cd metallic nanoparticles, {approx} 5 nm, formed and the distribution of nanoparticles is consistent with the morphological characteristics of the ripple pattern. This approach provides a means of fabricating surface nanostructure with various patterns and a controllable particle size and distribution by combining ion beam-induced phase decomposition with high-precision FIB patterning.

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The formation of palladium silicides near the interface may decrease hydrogen solubility at the effective metal/semiconductor ...

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The interaction between molecules and solid surfaces plays important roles in various applications, including catalysis, sensors, nanoelectronics, and solar cells. Surprisingly, a full understanding of molecule-surface interaction at the quantum mechanical level has not been achieved even for very simple molecules, such as water. In this mini-review, we report recent progresses and current status of studies on interaction between representative molecules and surfaces. Taking water/metal, DNA bases/carbon nanotube, and organic dye molecule/oxide as examples, we focus on the understanding on the microstructure, electronic property, and electron-ion dynamics involved in these systems obtained from first-principles quantum mechanical calculations. We find that a quantum mechanical description ...

UK PubMed Central (United Kingdom)

The geographical arrangement of people on the surface of the earth is approximated by a mathematical equation of 361 terms. This is a convenient form for comparison with other distributions and for...Full Text Available

UK PubMed Central (United Kingdom)

The binding of iodine-labelled plasminogen to Helicobacter pylori CCUG 17874 was characterized. Inhibition of the binding was observed after preincubation of H. pylori...Full Text Available

International Nuclear Information System (INIS)

The relaxations of the Ti(0001) and Zr(0001) surfaces are studied using the plane-wave-basis pseudopotential method within the local-density approximation. We find that the first interlayer spacings of Ti(0001) and Zr(0001) are contracted with respect to the bulk spacings by 6.8% and 6.1%, respectively. Such large relaxations for the close-packed surfaces of Ti and Zr are in good agreement with recent linear-augmented-plane-wave calculations. In addition, we predict a weak vibrational effect on the surface relaxation of Zr(0001) by considering the free energy in the quasiharmonic approximation. This result can be attributed to a very strong bonding between the first- and second-layer Zr atoms as a consequence of the bond-order endash bond-length correlation. copyright 1997 The American Physical Society.

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A method for calculating flow through an airfoil cascade drawn on a surface of revolution is discussed. The three-dimensional flow was assumed to be represented by part-channels of varying width. The basic equations are the equation of continuity and the ...

UK PubMed Central (United Kingdom)

Exposure of female rats to trichloroethylene (TCE), an environmental toxicant commonly found in ground and surface waters throughout the United States, reduces the fertilizability of oocytes...Full Text Available

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Nomographs that calculate the threshold values of surface fire parameters which lead to crown fire initiation were created by linking two separate fire behavior models: Van Wagner?s crown fire ignition criteria and Byram?s surface fire model. The nomographs were also based on the existing surface (fuel load, fuel heat content) and canopy (foliar moisture content, live crown base height) fuel models of Aleppo (Pinus halepensis Mill.) pine forests of Mediterranean Greece. The most important fire parameters for crown fire initiation that are calculated by the nomographs are the critical flame length and the forward spread rate of the surface fire. These parameters are readily observable in the field during fires. The nomographs provide a judicious way to assess whether a crown fire is likely ...

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The latent heat of evapotranspiration (ET) plays an important role in the assessment of drought severity as one sensitive indicator of land drought status. A simple and accurate method of estimating global ET for the monitoring of global land surface droughts from remote sensing data is essential. The objective of this research is to develop a hybrid ET model by introducing empirical coefficients based on a simple linear two-source land ET model, and to then use this model to calculate the Evaporative Drought Index (EDI) based on the actual estimated ET and the potential ET in order to characterize global surface drought conditions. This is done using the Global Energy and Water Cycle Experiment (GEWEX) Surface Radiation Budget (SRB) products, AVHRR-NDVI products from the Global Inventory ...

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Sulfuric acid hydrogen peroxide mixtures (SPM) are commonly used in the semiconductor industry to remove organic contaminants from wafer surfaces. This viscous solution is very difficult to rinse off wafer surfaces. Various rinsing conditions were tested and the resulting residual contamination on the wafer surface was measured. The addition of small amounts of a chemical base such as ammonium hydroxide to the rinse water has been found to be effective in reducing the surface concentration of sulfur and also mitigates the particle growth that occurs on SPM cleaned wafers. The volume of room temperature water required to rinse these wafers is also significantly reduced.

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The effect of the coated composite surface of particles on the mechanical properties of the powder bed was investigated. Polyethylene-silica surface composite powder was prepared at several coating ratios with Hybridizer. Various tests on mechanical properties of the powder bed were carried out with the prepared powder, and the following results were obtained: The ultimate tensile strength depends only on the cohesive force between particles, and the contact probability model of composite particles led to good agreement between the experimental and calculated values. The coefficient of internal friction and cohesive shear strength were influenced due to the interlocking effect of the surface roughness of composite particles. The effects of coating particles became small with dynamic properties like angle of repose. It is possible to control the mechanical properties in a step wise fashion by changing the coating ratio of ...

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Previous experimental data and theoretical analysis have demonstrated that ... products of a technological process) but also other contaminants. ..... Thorough outgassing of solar array surfaces may result in significant decrease of arc ...

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metric temperatures has been prepared showing the surface water temper- ... occasion, gray levels show different densities for similar water temper- ...

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

International Nuclear Information System (INIS)

The initial growth process and surface structure of thin Pd(silicide) films on clean Si(111)-7x7 surfaces have been studied by low energy ion scattering (ISS) and LEED-Auger techniques. Considerable reaction between Pd and Si at room temperature is observed to extend up to 25 ML thickness of deposited Pd. Heat treatment of the room temperature film produced epitaxial silicide Pd_2Si(0001) films covered with the accumulated elementary Si layers of 1-2 ML thickness. Deposition of 1/3 ML Pd onto a heated substrate gives a Pd-embedded ordered surface of Si(111)-#sq root#3x#sq root#3R30"0, the feature being similar to the cases of Ag, Au/Si(111) systems. (orig.).

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Aug 18, 2004 ... The Arabian Gulf region presents a challenge to meteorologists trying to simulate weather with computer models because sea-surface and land ...

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Means of intensifying heat transfer with nucleate boiling, based on boiling under constrained conditions (in slots, on a capillary-porous surface) are the most promising since a high intensity of heat transfer is ensured. In the present work we attempt to evolve the main assumptions for the physical model of the process of vapour formation under constrained conditions and to extend them to the boiling of cryogenic liquids on surfaces with a capillary-porous deposit; also, the results are given of experimental investigations of heat transfer with the boiling of nitrogen, oxygen and hydrogen at atmospheric perssures and below on capillary-porous surfaces of various metals of different structure produced by an electric arc method of gasothermal spray coating.