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Letteratura scientifica selezionata sul tema "Ultra high purity oxygen"

Autore: Grafiati

Pubblicato: 27 settembre 2024

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Articoli di riviste sul tema "Ultra high purity oxygen"

1

Ma, Ce, e Nishith Verma. "Moisture Drydown in Ultra-High-Purity Oxygen Systems". Journal of the IEST 41, n. 1 (14 gennaio 1998): 13–15. http://dx.doi.org/10.17764/jiet.41.1.ym44t93qn5467505.

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Semiconductor manufacturing fabs use ultra-high-purity (UHP) oxygen for various process applications such as oxide growth, plasma etch, and chemical vapor deposition. Moisture is identified as one of the key impurities that can affect device production. Moisture drydown in inert gas delivery systems was studied extensively. However, moisture drydown or outgassing characteristics in oxygen were found to be different from those of inert gas systems. Moisture adsorption and desorption in UHP oxygen systems were studied using advanced APIMS techniques for trace-level moisture analysis. To understand moisture reaction pathways, isotopic water was used as an adsorbate on 316L electropolished stainless steel (EPSS) surfaces. Experimental results from moisture drydown in the EPSS tubing were used to validate a theoretical model developed to predict the moisture drydown performance of large-scale, oxygen distribution systems. Both experimental and model results were shown to be useful in UHP oxygen system design, cost control, metrology, and contamination control.

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2

Yoshioka, Takayuki, Haruno Okochi e Ryosuke Hasegawa. "Determination of Ultra Low Contents of Oxygen in High Purity Iron". Materials Transactions, JIM 34, n. 6 (1993): 504–10. http://dx.doi.org/10.2320/matertrans1989.34.504.

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3

Suprihanto, Agus. "HIGH TEMPERATURE GAS NITRIDING TREATMENT OF AISI 430 USING LOW AND HIGH PURITY NITROGEN GAS". ROTASI 18, n. 3 (1 luglio 2016): 65. http://dx.doi.org/10.14710/rotasi.18.3.65-68.

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The properties of stainless steels can be improved by high temperature gas nitriding (HTGN) treatment. The improving of their properties are obtained from nitrogen atom which diffuse into stainless steel. Nitrogen gas is the main source of nitrogen atom on the HTGN treatment. Generally, these treatment use high purity of nitrogen gas. The aim of this research is to investigate the effect of nitrogen gas purity on the HTGN treatment for AISI 430. Stainless steel AISI 430 plate 2 mm thick was processed by HTGN treatment. The specimens was exposed at nitrogen gas atmosphere at temperature 1200oC and held for 2 hours prior quenching in water. The treatment used industrial/welding grade (99.5%) as low nitrogen gas purity and ultra high purity (UHP) grade (99.999%) as high nitrogen gas purity. The vickers micro-hardness test was conducted to evaluate the hardness distribution from surface into middle section of the specimens before and after treatment. Light optical microscope was applied to examine the microstructure of specimens after treatment. Metallographic examination shows both treatments using low and high purity gas have the same grain size. However HTGN treatment using low purity of nitrogen gas produces hardness slightly lower than the high purity. This is due the high content of impurity of the low purity gas that reduces the partial pressure of nitrogen gas. Another effect of impurity is the reaction between nitrogen gas and its impurity especially oxygen gas. These reactions reduce the amount of free nitrogen atom which diffuses on the stainless steel.

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4

Ma, Xiao Xuan, Zeng He Li, Tij Je Cai e Ya Zhen Liu. "Thermal Decomposition Dew Point Method for Determining the Trace Moisture in Ultra-Purity Ammonia". Advanced Materials Research 718-720 (luglio 2013): 571–75. http://dx.doi.org/10.4028/www.scientific.net/amr.718-720.571.

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This article introduced a fast and stable method on measuring the batches of trace moisture in ultra-purity ammonia gas .This method is based on ammonia decomposited reaction ,which occurs completely and irreversibly when ammonia is passed over nickel catalyst at high temperatures. While the trace water wapor passes though the catalyst unchanged. And the moisture of ammonia may be determined by measuring the dew point of the steam of hydrogen and nitrogen produced by decomposition of ammonia,combined with the trace oxygen content measured by GC,the content of trace moisture in ultra-purity ammonia gas can be got. Contrasted with Cavity Ring-down Spectroscopy (CRDS) and Infrared Absorption Spectroscopy (IR),Thermal Decomposition Dew Point method (TDDP) has high accuracy,good repeatability, stability and environmentally friendly.

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Shive, Larry W., Hai He Liang, Alexis Grabbe e Sasha Kweskin. "Indirect Ultra-Pure Water Metals Analysis by Extended Ion Exchange on a Silica Surface". Solid State Phenomena 187 (aprile 2012): 275–78. http://dx.doi.org/10.4028/www.scientific.net/ssp.187.275.

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Water purity is not taken for granted in the Semiconductor Industry. Ultra high purity water (UPW) is analyzed continuously in-line for particles and resistivity. Routine samples are automatically taken for total organic carbon (TOC), boron, silica and dissolved oxygen. Less routine analyses, such as metals, are done off-line. Metal content of UPW water is well below the detection limits of ICP-MS even with a pre-concentration step. As a result, metals content may vary in the water without being detected. These variations may affect device performance and yield while the root cause may go undetected.

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Lee, Seong Hee, Seung Zeon Han e Cha Yong Lim. "Nano-Structured High Purity Copper Processed by Accumulative Roll-Bonding". Key Engineering Materials 317-318 (agosto 2006): 239–42. http://dx.doi.org/10.4028/www.scientific.net/kem.317-318.239.

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Accumulative roll-bonding (ARB) process was applied to an oxygen free copper for improvement of the mechanical properties via ultra grain refinement to nanometer order level. Two copper sheets 1mm thick, 30mm wide and 300mm long are degreased and wire-brushed for sound bonding. The sheets are then stacked to each other, and cold-roll-bonded by 50% reduction rolling. The sheet is then cut to the two pieces of same length and the same procedure was repeated to the sheets. The ARB process up to eight cycles (an equivalent thickness strain of 6.4) is successfully performed at ambient temperature. TEM observation reveals that ultrafine grains, hardly containing the dislocation interior, begin to develop at the third cycle, and after the sixth cycle they cover most of regions of samples. The morphology of ultrafine grains formed is different from that of aluminum alloys. Tensile strength of the ARB-processed copper increases with the equivalent strain up to a strain of ~3.2, in which it reached 390 MPa, ~2.1 times higher than the initial value. However, the strength hardly changed at the strain above ~3.2.

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7

Fahrenholtz, W. G., G. E. Hilmas e Ruixing Li. "Densification of ultra-refractory transition metal diboride ceramics". Science of Sintering 52, n. 1 (2020): 1–14. http://dx.doi.org/10.2298/sos2001001f.

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The densification behavior of transition metal diboride compounds was reviewed with emphasis on ZrB2 and HfB2. These compounds are considered ultra-high temperature ceramics because they have melting temperatures above 3000?C. Densification of transition metal diborides is difficult due to their strong covalent bonding, which results in extremely high melting temperatures and low self-diffusion coefficients. In addition, oxide impurities present on the surface of powder particles promotes coarsening, which further inhibits densification. Studies prior to the 1990s predominantly used hot pressing for densification. Those reports revealed densification mechanisms and identified that oxygen impurity contents below about 0.5 wt% were required for effective densification. Subsequent studies have employed advanced sintering methods such as spark plasma sintering and reactive hot pressing to produce materials with nearly full density and higher metallic purity. Further studies are needed to identify fundamental densification mechanisms and further improve the elevated temperature properties of transition metal diborides.

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8

Ma, Ce, Eric Shero, Nishith Verma, Stephen Gilbert e Farhang Shadman. "Permeation of Moisture and Oxygen Through Polymeric O-Rings". Journal of the IEST 38, n. 2 (31 marzo 1995): 43–46. http://dx.doi.org/10.17764/jiet.2.38.2.k6491358g0l83691.

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The permeation coefficients of H2O and O2 through polymeric O-rings were obtained in this study. Increases of trace level impurities in an ultra-high purity nitrogen purge gas due to the permeation processes were measured using an atmospheric pressure ionization mass spectrometer (APIMS). In this paper, the experimental results of nine different O-ring samples (Kalrez, Chemraz, Teflon, Vespel, Viton) are reported. The Kalrez "wet" O-ring showed the lowest moisture permeation coefficient of 1.5×-1010 [cm3 gas(STP). cm polymer]/[cm2 polymer · sec · torr] and Vespel displayed the lowest oxygen permeation coefficient of 0.01×-1010 [cm3 gas(STP) · cm polymer]/[cm2 polymer · sec · torr] and room temperature. In addition, permeation coefficients at 50°C and 75°C are presented. The activation energies varied from about 18 to 51 kJ/mole/°K for both H2O and O2.

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Kazemi, Faramarz, e Behzad Nayebi. "A perspective to efficient synthesis of zirconium carbide via novel pyro-vacuum method: lower temperatures and enhanced purity". Synthesis and Sintering 4, n. 3 (30 agosto 2024): 197–202. http://dx.doi.org/10.53063/synsint.2024.43233.

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The use of ultra-high temperature ceramics (UHTCs) as a novel additive in the refractory industry is becoming increasingly popular. However, the synthesis of such materials is associated with some commercial obstacles, mainly high-temperature synthesis methods. In the present study, the pyro-vacuum method is presented as a new method to decrease the final product's synthesis temperature and oxygen content. Some thermodynamic aspects and phase evolution of the materials during the synthesis procedure are described for the synthesis of non-oxide material. Conclusively, it seems that by applying vacuum conditions, the final UHTC phases can be synthesized at significantly lower temperatures (>400 °C lower, for ZrC), if adequate powder mixtures are considered. Also due to phase analysis, it was found that the oxygen content of the final phase is lower than the conventional routes and other references. The process provides promising prospects for the economic synthesis of UHTCs.

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Xiao, Tingting, Qi Yang, Jian Yu, Zhengwei Xiong e Weidong Wu. "Annealing Condition Effects on the Structural Properties of FePt Nanoparticles Embedded in MgO via Pulsed Laser Deposition". Nanomaterials 11, n. 1 (8 gennaio 2021): 131. http://dx.doi.org/10.3390/nano11010131.

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FePt nanoparticles (NPs) were embedded into a single-crystal MgO host by pulsed laser deposition (PLD). It was found that its phase, microstructures and physical properties were strongly dependent on annealing conditions. Annealing induced a remarkable morphology variation in order to decrease its total free energy. H2/Ar (95% Ar + 5% H2) significantly improved the L10 ordering of FePt NPs, making magnetic coercivity reach 37 KOe at room temperature. However, the samples annealing at H2/Ar, O2, and vacuum all showed the presence of iron oxide even with the coverage of MgO. MgO matrix could restrain the particles’ coalescence effectively but can hardly avoid the oxidation of Fe since it is extremely sensitive to oxygen under the high-temperature annealing process. This study demonstrated that it is essential to anneal FePt in a high-purity reducing or ultra-high vacuum atmosphere in order to eliminate the influence of oxygen.

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Più fonti

Tesi sul tema "Ultra high purity oxygen"

1

Liang, Fangyi [Verfasser]. "Investigation and development of novel oxygen permeable membranes for high-purity oxygen production / Fangyi Liang". Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2013. http://d-nb.info/103405323X/34.

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2

Pham, David, e David Pham. "Processing High Purity Zirconium Diboride Ultra-High Temperature Ceramics: Small-to-Large Scale Processing". Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621315.

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Abstract (sommario):

Next generation aerospace vehicles require thermal protection system (TPS) materials that are capable of withstanding the extreme aerothermal environment during hypersonic flight (>Mach 5 [>1700 m/s]). Ultra-high temperature ceramics (UHTC) such as zirconium diboride (ZrB₂) are candidate TPS materials due to their high-temperature thermal and mechanical properties and are often the basis for advanced composites for enhanced oxidation resistance. However, ZrB₂ matrix impurities in the form of boron trioxide (B₂O₃) and zirconium dioxide (ZrO₂) limit the high-temperature capabilities. Electric based sintering techniques, such as spark plasma sintering (SPS), that use joule heating have become the preferred densification method to process advanced ceramics due to its ability to produce high density parts with reduced densification times and limit grain growth. This study focuses on a combined experimental and thermodynamic assisted processing approach to enhance powder purity through a carbo- and borocarbo-thermal reduction of oxides using carbon (C) and boron carbide (B₄C). The amount of oxides on the powder surface are measured, the amount of additive required to remove oxides is calculated, and processing conditions (temperature, pressure, environment) are controlled to promote favorable thermodynamic reactions both during thermal processing in a tube furnace and SPS. Untreated ZrB₂ contains 0.18 wt%O after SPS. Additions of 0.75 wt%C is found to reduce powder surface oxides to 0.12 wt%O. A preliminary Zr-C-O computational thermodynamic model shows limited efficiency of carbon additions to completely remove oxygen due to the solubility of oxygen in zirconium carbide (ZrC) forming a zirconium oxycarbide (ZrCₓOᵧ). Scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) with atomic scale elemental spectroscopy shows reduced oxygen content with amorphous Zr-B oxides and discreet ZrO₂ particle impurities in the microstructure. Processing ZrB₂ with minimal additions of B₄C (0.25 wt%) produces high purity parts after SPS with only 0.06 wt%O. STEM identifies unique “trash collector” oxides composed of manufacturer powder impurities of calcium, silver, and yttrium. A preliminary Zr-B-C-O thermodynamic model is used to show the potential reaction paths using B₄C that promotes oxide removal to produce high-purity ZrB₂ with fine grains (3.3 𝜇m) and superior mechanical properties (flexural strength of 660MPa) than the current state-of-the-art ZrB₂ ceramics. Due to the desirable properties produced using SPS, there is growing interest to advance processing techniques from lab-scale (20 mm discs) to large-scale (>100 mm). The advancement of SPS technologies has been stunted due to the limited power and load delivery of lab-scale furnaces. We use a large scale direct current sintering furnace (DCS) to address the challenges of producing industrially relevant sized parts. However, current-assisted sintering techniques, like SPS and DCS, are highly dependent on tooling resistances and the electrical conductivity of the sample, which influences the part uniformity through localized heating spots that are strongly dependent on the current flow path. We develop a coupled thermal-electrical finite element analysis model to investigate the development and effects of tooling and current density manipulation on an electrical conductor (ZrB₂) and an electrical insulator, silicon nitride (Si₃N₄), at the steady-state where material properties, temperature gradients and current/voltage input are constant. The model is built based on experimentally measured temperature gradients in the tooling for 20 mm discs and validated by producing 30 mm discs with similar temperature gradients and grain size uniformity across the part. The model aids in developing tooling to manipulate localize current density in specific regions to produce uniform 100 mm discs of ZrB₂ and Si₃N₄.

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Barber, Tyler William. "Superoxygenation : analysis of oxygen transfer design parameters using high purity oxygen and a pressurized aeration column". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/49938.

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Supplying oxygen to water via the physical process of aeration is the most widely used water treatment technology. It supports microbial growth in water and wastewaters by introducing dissolved oxygen to the water, stabilizing organic matter and providing the necessary oxygen for many other aquatic species to survive. There exists the potential for much improvement in aeration techniques, which can account for 60 percent of the energy required for water treatment. This research aimed to analyze one such technique that has limited research of this magnitude, aerating water under high pressures with high-purity oxygen. Increasing the partial pressure of oxygen in the aeration gas, by way of Henry's law, increases the saturation concentration of the water and, thus, several aeration design parameters. The parameters required for aeration design and sought after in this research are: the mass transfer coefficient (KLa), saturation concentration (C*sat), standard oxygen transfer rate (SOTR), standard aeration efficiency (SAE), and the standard oxygen transfer efficiency (SOTE). This research compared the obtained design values under gauge pressures of 0, 50, 100, 150, and 200 kPa using air and Pressure Swing Adsorption (PSA) oxygen in an 18.5 foot (5.6 meter) aeration column, allowing for comparative analysis of the design parameters for aeration. Results show that, with increasing pressure for both air and PSA oxygen: KLa decreases, C*sat increases; however, at a rate other than predicted by Henry's law, the SOTR remains constant, the SAE decreases, and the SOTE increases. Between air and PSA oxygen, PSA was found to have a slightly larger KLa, larger C*sat, larger SOTR, lower SAE, and a higher SOTE.
Applied Science, Faculty of
Civil Engineering, Department of
Graduate

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4

Hagar, Peter David. "Factors affecting the performance of activated sludge in a modified Ludzack Ettinger process fed with high purity oxygen". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1995. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq23328.pdf.

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5

Taher, Mohamed Asaad Asaad. "Model-based evaluation of the integration of solid oxide fuel cells and electrolysis cells for high purity oxygen production". Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/58317.

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Oxygen is used for a wide range of applications, with a globally projected production capacity of 1.8 million tonne per day in 2020. Depending on the economic range and the required purity, various methods are used to extract oxygen. Conventionally, cryogenic air separation is used for the large to medium production scale, characterised by high purity oxygen and relatively low energy consumption, whilst pressure swing adsorption (PSA) is widely used for the small-scale production, with lower oxygen purity and higher energy consumption. A high-efficiency system for high purity oxygen production based on the integration of solid oxide- fuel and electrolysis cells (SOFC and SOEC) was first proposed by Iora and Chiesa in 2009. However, the lack of a detailed methodology and the novelty of such a system necessitated a system-level energy analysis with an emphasis on the SOFC and SOEC to understand the nature of thermal and electrical coupling between them. Here, the initial feasibility of the system has been evaluated considering the lumped-parameter modelling of the SOFC, SOEC and balance of plant. A system energy consumption that is significantly less than that of PSA systems was predicted, and a significant contribution of the stack energy consumption to the overall system energy consumption was observed, suggesting the need for a thorough examination of the electrochemical models. Therefore, the parameter estimation technique has been implemented to validate the electrochemical models based on a 5-cell stack and a single repeating unit SOEC experimental data. A good agreement was obtained between the experimental and model-predicted cell potential across all operating conditions, and key electrochemical parameters were estimated with confidence. The validated electrochemical model has then been integrated into a newly-developed onedimensional model of a planar SOFC-SOEC stack to further improve the predictions of the stack and system performance. Significant contributions of experimental validation and distributed modelling on enhancing the predictions of the stack model were observed. The advantages of the system over PSA systems in terms of energy efficiency and oxygen purity were confirmed. A potential design point of the system was selected via a techno-economic study, revealing an extremely low contribution of the electricity cost to the total cost of production. An adequate thermal integration at both the stack and system levels were demonstrated at the design point.

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6

Dittler, Roy Frank. "Reducing Ultra-High-Purity (UHP) Gas Consumption by Characterization of Trace Contaminant Kinetic and Transport Behavior in UHP Fabrication Environments". Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/321322.

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Trends show that the fraction of the world's population with electronic devices using modern integrated circuits is increasing at a rapid rate. To meet consumer demands: less expensive, faster, and smaller electronics; while still making a profit, manufacturers must shrink transistor dimensions while increasing the number of transistors per integrated circuit; a trend predicted by Gorden E. Moore more than 44 years prior. As CMOS transistors scale down in size, new techniques such as atomic-layer deposition (ALD) are used to grow features one atomic layer at a time. ALD and other manufacturing processes are requiring increasingly stringent purities of process gases and liquids in order to minimize circuit killing defects which reduces yield and drives up manufacturing cost. Circuit killing defects caused by impurity incursions into UHP gas distribution system can come from a variety of sources and one of the impurity transport mechanisms investigated was back diffusion; the transport of impurities against convective flow. Once impurity incursions transpire, entire production lines are shut down and purging with UHP gas is initiated; a process that can take months thus resulting in tens of millions of dollars in lost revenue and substantial environment, safety, and health (ESH) impacts associated with high purge gas consumption. A combination of experimental investigation and process simulation was used to analyze the effect of various operational parameters on impurity back diffusion into UHP gas distribution systems. Advanced and highly sensitive analytical equipment, such as the Tiger Optics MTO 1000 H2O cavity ring-down spectrometer (CRDS), was used in experiments to measure real time back diffusing moisture concentrations exiting an electro-polished stainless-steel (EPSS) UHP distribution pipe. Design and operating parameters; main and lateral flow rates, system pressure, restrictive flow orifice (RFO) aperture size, and lateral length were changed to impact the extent of back diffusing impurities from a venting lateral. The process model developed in this work was validated by comparing its predictions with data from the experiment test bed. The process model includes convection, molecular diffusion in the bulk, surface diffusion, boundary layer transport, and all modes of dispersion; applicable in both laminar and turbulent flow regimes. Fluid dynamic properties were directly measured or were obtained by solving Navier-Stokes and continuity equations. Surface diffusion as well as convection and dispersion in the bulk fluid played a strong role in the transport of moisture from vents and lateral branches into the main line. In this analysis, a dimensionless number (Peclet Number) was derived and applied as the key indicator of the relative significance of various transport mechanisms in moisture back-diffusion. Guidelines and critical values of Peclet number were identified for assuring the operating conditions meet the purity requirements at the point of use while minimizing UHP gas usage. These guidelines allowed the determination of lateral lengths, lateral diameters, flow rates, and restrictive flow device configurations to minimize contamination and UHP gas consumption. Once a distribution system is contaminated, a significant amount of purge time is required to recover the system background due to the strong interactions between moisture molecules and the inner surfaces of the components in a gas distribution system. Because of the very high cost of UHP gases and factory downtime, it is critical for high-volume semiconductor manufacturers to reduce purge gas usage as well as purge time during the dry-down process. The removal of moisture contamination in UHP gas distribution systems was approached by using a novel technique dubbed pressure cyclic purge (PCP). EPSS piping was contaminated with moisture, from a controlled source, and then purged using a conventional purge technique or a PCP technique. Moisture removal rates and overall moisture removal was determined by measuring gas phase moisture concentration in real time via a CRDS moisture analyzer. When compared to conventional purge, PCP reduced the time required and purge gas needed to clean the UHP gas distribution systems. However, results indicate that indiscriminately initiating PCP can have less than ideal or even detrimental results. An investigation of purge techniques on the removal of gas phase, chemisorbed, and physisorbed moisture, coupled with the model predictions, led to the testing of hybrid PCP. The hybrid PCP approach proved to be the most adaptable purge technique and was used in next phase of testing and modeling. Experiments and modeling progressed to include testing the effectiveness of hybrid PCP in systems with laterals; more specifically, laterals that are "dead volumes" and results show that hybrid PCP becomes more purge time and purge gas efficient in systems with increasing number and size of dead volumes. The process model was used as a dry-down optimization tool requiring inputs of; geometry and size, temperature, starting contamination level, pressure swing limits of inline equipment, target cleanliness, and optimization goals; such as, minimizing pure time, minimizing purge gas usage, or minimizing total dry-down cost.

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7

Wang, Hao. "Characterization and Control of Molecular Contaminants on Oxide Nanoparticles and in Ultra High Purity Gas Delivery Systems for Semiconductor Manufacturing". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/293417.

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Molecular contaminants on the surface of nanoparticles (NPs) are critical in determining the environmental safety and health (ESH) impacts of NPs. In order to characterize the surface properties that relate to adsorption and desorption interactions, a method has been developed for studying the dynamic interactions of adsorbing species on NP samples. The results are analyzed using a process simulator to determine fundamental properties such as capacity, affinity, rate expressions, and activation energies of NP interactions with contaminants. The method is illustrated using moisture as a representative model compound and particles of SiO₂, HfO₂, and CeO₂, which are three oxides used in semiconductor manufacturing. The effect of particle size and temperature on the surface properties of porous oxide NPs was investigated. Infrared spectra peaks corresponding to the stretching vibration of water molecules were monitored by in-site Fourier transform infrared (FTIR) spectroscopy. These are related to the moisture concentration on the surface of NPs. A transient multilayer model was developed to represent the fundamental steps in the process. The thermal stability of adsorbed species and the strength of bonding to the surface were evaluated by determining the activation energies of the various steps. The results indicate that the surface interaction parameters are dependent on species, temperature, and particle size. SiO₂ has the highest adsorption capacity and therefore is most prone to the adsorption of moisture and similar contaminants. However, the affinity of the NPs for H₂O retention is highest for CeO₂ and lowest for SiO₂. As temperature decreases, NPs exhibit a higher saturated moisture concentration and are more prone to the adsorption of moisture and similar contaminants. Furthermore, smaller NPs have a higher saturated surface concentration and a slower response to purging and desorption. Factors contributing to the environmental and health impact of NPs (extent of surface coverage, capacity, and activation energy of retention) have been investigated during this study. The second objective of this study is to develop a method to measure and control the contamination in ultra-high-purity (UHP) gas delivery systems. Modern semiconductor manufacturing plants have very stringent specifications for the moisture content at the point-of-use, usually below several parts per billion (ppb). When the gas delivery system gets contaminated, a significant amount of purge time is required for recovery of the background system. Therefore, it is critical for high-volume semiconductor manufacturers to reduce purge gas usage as well as purge time during the dry-down process. A method consisting of experimental research and process simulations is used to compare steady-state purge (SSP) process of constant pressure and flow rate with the pressure-cycle purge (PCP) process of cyclic pressure and flow rate at a controlled interval. The results show that the PCP process has significant advantages over the SSP process under certain conditions. It can reduce the purge time and gas usage when the gas purity at point-of-use is the major concern. The process model is validated by data congruent with the experimental results under various operating conditions and is useful in conducting parametric studies and optimizing the purge process for industrial applications. The effect of key operational parameters, such as start time of PCP process as well as choice of PCP patterns has been studied.

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8

Hernández, Hernández Armand. "Ultra-high resolution environmental and climatic reconstruction using oxygen and carbon isotopes of diatom frustules". Doctoral thesis, Universitat de Barcelona, 2010. http://hdl.handle.net/10803/670535.

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Calcareous microfossils are not always present in marine or lacustrine sediments owing to unfavourable ecological or post-depositional conditions. These non-carbonated sediments sometimes contain abundant biogenic silica, rendering them suitable for studies of stable isotopes. For this reason, considerable progress has been made in the study of biogenic silica using isotopes in recent years. Diatom isotopes are increasingly being used for palaeoenvironmental reconstructions in lacustrine sedimentary records. Tropical proxy records offer valuable insights into past climate and environmental changes of the Earth and into possible future climate change scenarios. Research into tropical regions has therefore become a key issue among palaeoclimatologists. Influenced by the tropical circulation in the north, and by the mid-latitude westerlies in the south, the Central Andes are an ideal site to study past variations of atmospheric circulation systems. Thus, the Andean Altiplano has become a key region for the study of late Quaternary climate change in South America. Sedimentary records of high-altitude Andean Altiplano lakes usually preserve an excellent centennial- to millennial-scale record of effective moisture fluctuations and source changes during the Late Glacial and Holocene despite the fact that the interpretation is not always straightforward. Oxygen and carbon isotope analyses in carbonates (δ18Ocarbonate and δ13Ccarbonate) and δ13Cbulk have been successfully used to reconstruct the hydrological responses to climate change in different Andean lacustrine systems to date. No attempt, however, has been made to use δ18Odiatom and δ13Cdiatom despite the fact that they are usually the best preserved fossils in the sedimentary record of the Andean Altiplano lakes. For this reason, the aims of the PhD Thesis are twofold: a) to explore the possibilities that the study of δ18Odiatom and δ13Cdiatom can offer in palaeoenvironmental reconstructions, and b) to carry out high- and ultra-high resolution environmental and climate reconstructions in the Andean Altiplano during the Late Glacial- Early Holocene transition using these stable isotopes. The thesis focuses on new and poorly documented fields where δ18Odiatom and δ13Cdiatom can successfully be applied to lacustrine sediments. It shows how stable isotopes from diatom silica may be used a) to highlight the importance of reconstructing the different evolutionary stages of lake ontogeny given that climate derived palaeohydrological signals can be distorted by changes in lake morphology b) as a main proxy in ultra-high resolution moisture balance reconstructions forced by fluctuations in the intensity of the ENSO and solar activities c) to reveal the major biogeochemical processes that give rise to the formation of rhythmites, and finally d) to reconstruct the regional environmental evolution at centennial-to-millenial time scales.
La tesis está basada en la reconstrucción ambiental y climática a muy alta resolución mediante los sedimentos laminados y ricos en diatomeas de un lago tropical situado en los Andes Centrales. Para la reconstrucción se ha utilizado la novedosa técnica del análisis de isótopos estables (δ18Odiat y δ13Cdiat) de la sílice de las diatomeas. Los principales resultados y conclusiones son: Diversos factores ambientales pueden influir en los valores de δ18Odiat. Los registros de δ18Odiat en sistemas lacustres cerrados no pueden ser simplemente interpretados en términos de seco o húmedo, sino que es imperativo entender la hidrología y geomorfología de cada sistema antes de hacer una interpretación de tipo estrictamente climático como se había hecho hasta la fecha. Por su parte, los análisis de δ13Cdiat han demostrado que esta técnica es una herramienta válida para realizar reconstrucciones del ciclo del carbono en los lagos, así como para dar un mejor punto de vista del ciclo del carbono a nivel global. La unidad sedimentaria laminada del Lago Chungará está formada por ritmitas multianuales compuestas por láminas de color blanco y verde. Estás láminas son ricas en diatomeas y son el resultado de diferentes procesos lacustres. Las láminas de claras se formaron como consecuencia de «blooms» extraordinarios de muy corta duración (días o semanas). Las láminas oscuras se depositaron a lo largo de diversos años bajo diferentes condiciones de la columna de agua y por tanto representan las condiciones de base del lago. Los valores de δ18Odiat muestran que los «blooms» extraordinarios fueron más intensos con condiciones de bajo nivel del lago, mientras que la formación de láminas oscuras se vio especialmente inducida por subidas del nivel. Al mismo tiempo, los valores de δ13Cdiat indican que la disponibilidad de carbono fue superior durante los «blooms» extraordinarios de diatomeas. La combinación de los dos registros ha destacado les complejas relaciones entre los procesos limnológicos, los procesos de la cuenca de drenaje, la hidrología y los forzamientos climáticos. El registro de isotopía expone claramente que, según la escala temporal, un tipo de proceso puede dominar sobre los otros en la interpretación de la isotopía.

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Simone, Daniela. "The Production and Characterisation of High Purity Ozone and Experimental and Modelling Studies of Anomalous Oxygen Isotope Effects in the Formation of Carbon Dioxide from Irradiated Mixtures of Carbon Monoxide and Ozone or Oxygen". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-01023002.

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The ozone formation reaction O+O2+M→O3+M is a unique example of a chemical reaction that leads to an anomalous isotopic composition of the products, most likely due to symmetry - breaking effects. So far, results on other chemical systems that might show similar effects are spurious, even though such claims concerning reactions other than the formation of ozone have been made repeatedly.This applies in particular to the spin forbidden O+CO+M→CO2+M reaction, where two studies report a mass-independent fractionation of about 8%. Nevertheless, the presence of ozone in these experiments raises questions as to the validity of this assertion. We thus make a new attempt to study the O+CO+M reaction in the photoreactor at CCAR (University of Copenhagen) where reagents and contaminants are monitored on-line by FTIR spectroscopy. This study combined with the analysis of the spectral distribution of the employed lamps and isotope kinetic modeling lead to a complete re-interpretation of previous experiments. We conclude that available measurements are more compatible with the hypothesis that there is no mass-independent isotope fractionation in the O+CO reaction. We propose that all observations can be completely explained by an isotope transfer from ozone, involving photolytic production of O(1D) that in turn leads to OH radicals, which then rapidly form CO2 from reaction with CO. We also present a method to produce pure ozone samples and derive an upper limit on nitrogen oxide contaminations based on mass spectrometer measurements. These values will serve as benchmarks values for future studies of ozone absorption cross sections in the IR and UV.

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Gauthiez, Putallaz Laure. "Tracing fluids during medium to ultra-high pressure metamorphism: insights by combined in situ oxygen isotopes and trace element analysis". Phd thesis, Canberra, ACT : The Australian National University, 2017. http://hdl.handle.net/1885/157028.

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Fluids are an essential component of tectonic and metamorphic processes such as subduction and crustal anatexis. Fluids are elusive to trace as they commonly escape high-pressure rocks. This study uses oxygen isotopes to identify fluid influxes in metamorphic rocks and tie them to geologic events, measuring δ18O in situ by ion microprobe in garnet, zircon, apatite, monazite and lawsonite. New method developments are presented for δ18O analyses by Sensitive High Resolution Ion MicroProbe: (i) in apatite, a precision of 0.2‰ (1σ) is achieved; diffusion modelling shows that apatite is expected to preserve oxygen isotope signatures from 400-450°C and below; (ii) a matrix correction scheme is derived for monazite oxygen isotope measurement, allowing a precision of 0.35‰ (1σ); (iii) rutile oxygen isotope measurements yield major orientation effects. Fluid pulses generated by prograde dehydration reactions are investigated in the ultra-high-pressure Dora Maira whiteschists, Italy. Rare-earth-element abundances indicate prograde monazite and zircon growth (pre-garnet 34.5±0.7 Ma, 6.4‰ and syn-garnet at 34.9±0.4 Ma, 6.2 to 6.7‰), which are linked to dehydration reactions using thermodynamic modelling. This allows drawing a P-T-time-fluid path that implies that (i) prograde subduction from 25 to 45 kbar occurred within a couple of My (minimum burial rate of 2 cm/yr); (ii) high-pressure fluids were of internal origin and metasomatism likely have occurred at a rifting phase before subduction. Four phases of fluid circulations are identified in the high-pressure low-temperature lawsonite eclogites and blueschists of the Tavşanlı zone, Turkey. The Halilbağı unit is an oceanic complex containing various sediments and serpentinite together with 222±5 Ma MORB and 123±3 Ma OIB lithologies (zircon U-Pb, whole-rock major and trace elements). The sequence was thoroughly altered and mechanically mixed at the seafloor and in the accretionary prism, leading to overall high whole-rock δ18O of 11.0-17.0‰ for metabasites. Garnet, apatite and lawsonite are zoned in δ18O in samples across the unit, with contrasts of 7‰ in a MORB eclogite (garnet core: 6.3‰, rim: 13‰) and 3‰ in an impure quartzite (apatite core: 19.5‰, rim: 17‰). Petrographic and trace element evidence allow identifying localised prograde-peak fluid influx, and homogenisation of oxygen isotopes and Sr/Pb at the start of retrogression by pervasive fluid circulation across the unit. Heavy δ18O signatures (WR: 11.8 to 13.6‰) were measured in Eoarchaean metasediments from the Isua supracrustal belt, Greenland. The sources of the sediments were mantle-derived boninites (mafic component) and andesites (felsic component, detrital/volcanic zircons dated at 3709 Ma,δ18O 5.3‰). Three garnet growth zones record high δ18O (9 to 10‰), in equilibrium with the whole-rock. Rare-earth-element and petrographic evidence allow identifying a higher-pressure signature in the high- δ18O garnet, which can be linked to a 3690-3660 Ma tectonic event. The elevated δ18O signature in the metasediments thus originated from surficial processes (e.g. weathering) before 3690Ma. Melting of such heavy-δ18O amphibolite-facies sediments could represent a source for early Archean high-δ18O magmas and zircons. The combination of oxygen isotope and trace element microanalysis in zoned minerals proves a powerful tool for uncovering multistage minor and major fluid infiltration events in metamorphic rocks.

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Libri sul tema "Ultra high purity oxygen"

1

Outlaw, R. A. Permeation of oxygen through high purity, large grain silver. [Washington, D.C.]: National Aeronautics and Space Administration, Scientific and Technical Information Office, 1987.

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2

Waseda, Yoshio, e Minoru Isshiki, a cura di. Purification Process and Characterization of Ultra High Purity Metals. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6.

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3

Neuharth, Clark R. Ultra-high-purity silicon for infrared detectors: A materials perspective. Washington, D.C: U.S. Dept. of the Interior, Bureau of Mines, 1989.

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Neuharth, Clark R. Ultra-high-purity silicon for infrared detectors: A materials perspective. Washington, DC: Dept. of the Interior, 1989.

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5

Waseda, Yoshio. Purification Process and Characterization of Ultra High Purity Metals: Application of Basic Science to Metallurgical Processing. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002.

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6

Yoshio, Waseda, e Isshiki Minoru 1948-, a cura di. Purification process and characterization of ultra high purity metals: Application of basic science to metallurgical processing. Berlin: Springer-Verlag, 2002.

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7

Ultra high purity fluid: Markets, technologies, players, users. Norwalk, CT: Business Communications Co., 1989.

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8

McWhirter, John R. Use of High-Purity Oxygen in the Activated Sludge. Taylor & Francis Group, 2021.

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9

(Editor), Yoshio Waseda, e Minoru Isshiki (Editor), a cura di. Purification Process and Characterization of Ultra High Purity Metals. Springer, 2001.

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10

Purification Process and Characterization of Ultra High Purity Metals. Island Press, 2001.

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Capitoli di libri sul tema "Ultra high purity oxygen"

1

Okabe, T. H., K. T. T. Jacob e Y. Waseda. "The Thermodynamics of Oxygen in Reactive Metals". In Purification Process and Characterization of Ultra High Purity Metals, 3–37. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_1.

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2

Hashimoto, E., e Y. Ueda. "Electrical Properties of Ultra-High-Purity Metals". In Purification Process and Characterization of Ultra High Purity Metals, 249–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_9.

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Kekesi, T., e M. Isshiki. "Principles of Metal Purification and Purity Evaluation". In Purification Process and Characterization of Ultra High Purity Metals, 39–69. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_2.

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4

Seeger, A. "Atomic Defects in High-Purity Metals: Fundamentals and Equilibrium Concentrations". In Purification Process and Characterization of Ultra High Purity Metals, 349–402. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_12.

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5

Suzuki, S. "Surfaces and Interfaces". In Purification Process and Characterization of Ultra High Purity Metals, 277–304. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_10.

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6

Hollang, L. "Mechanical Properties". In Purification Process and Characterization of Ultra High Purity Metals, 305–48. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_11.

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7

Kekesi, T., e M. Isshiki. "The Purification of Base Transition Metals". In Purification Process and Characterization of Ultra High Purity Metals, 71–101. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_3.

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Koethe, A. "Refractory Metals". In Purification Process and Characterization of Ultra High Purity Metals, 103–43. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_4.

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9

Fort, D. "Purification of the Rare Earth Metals". In Purification Process and Characterization of Ultra High Purity Metals, 145–77. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_5.

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10

Mimura, K., e M. Isshiki. "Hydrogen Plasma Arc Melting". In Purification Process and Characterization of Ultra High Purity Metals, 181–202. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56255-6_6.

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Atti di convegni sul tema "Ultra high purity oxygen"

1

Dworak, Adam, Piotr Koruba, Jaroslaw Sienicki e Piotr Jurewicz. "Application of Ultra High Speed Laser Cladding Technology for Functional Coatings Deposition". In Vertical Flight Society 74th Annual Forum & Technology Display, 1–6. The Vertical Flight Society, 2018. http://dx.doi.org/10.4050/f-0074-2018-12807.

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The technology of high speed laser deposition is a development of the method of applying functional coatings using a laser beam. It is characterized by high surfacing speeds, allowing high cooling rates, little mixing with the substrate, which leads to a high purity of the padding material and an increase in the properties of the applied layer compared to conventional laser welding. This paper presents a description of the technology of high speed laser deposition in an application for the aviation industry. The prepared stand for the implementation of the process and its verification on the aircraft landing gear component, modified as part of the AMpHOra project, has been presented. The project was carried out as part of the PZL Mielec consortium and with the scientific partner of the Wrocław University of Technology. The results presented in the article show that the coatings obtained by this technology can be competitive with hard chromium electrolytic coatings.

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Ogawa, Yoji, e Takao Morita. "Influence of Oxygen on Electrode Consumption and Penetration in GTA Welding". In ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/omae2004-51244.

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Principle of Gas Tungsten Arc Welding is quite simple. Electron, which is emitted from Tungsten electrode, hits into the metal, and the heat from this impingement produce enough heat for fusion welding. However, actual behaviors are quite complicated. Electron emission is much influenced by physical condition of cathode and ambient circumstance. Considerable electron emits from unbelievable location of the cathode, especially at the ignition stage when the cathode is not enough hot. The anode spot, where main electrons hit into the metal, is also much influenced by surface condition and purity of shielding gas. The anode spot is usually appeared at the center of molten pool where the temperature seems to be maximum value. But, it sometimes moves irregularly or hits on the solid surface. This situation is mainly caused by oxidized layer on the metal or molten pool. Some minor elements on the metal act as a kind of catalytic agent. It sometimes drastically changes weld geometry. An amount of erosion on cathode surface is increased with increased oxygen contents. The penetration depth is also increased with oxygen contents. Plasma condition is also changed, because cathode and anode conditions are closely connected with plasma condition. Dynamic behavior of arc-cathode and arc-anode reactions was observed by ultra-high speed video system in a chamber from vacuum to high pressure, where contents of gas are controlled. Effects of oxygen and minor elements on anode and cathode reactions were considered.

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Kuleshov, Serhii, Olha Medvezhynska, Inessa Novoselova, Anatoliy Omel’chuk e Valerii Bykov. "Electrochemical synthesis of ultra-dispersed tungsten powders in molten salts". In IXth INTERNATIONAL SAMSONOV CONFERENCE “MATERIALS SCIENCE OF REFRACTORY COMPOUNDS”. Frantsevich Ukrainian Materials Research Society, 2024. http://dx.doi.org/10.62564/m4-sk1135.

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The development of energy-efficient and environmentally friendly methods for producing ultrafine tungsten powders and its compounds is an urgent task due to the wide range of their applications. The method of electrochemical reduction of W in molten salts opens up new prospects for obtaining nano-sized tungsten powders and coatings of high purity from various precursors (oxides, sulfides, nitrides) of different morphologies and structures at low temperatures (600–900°C). The article presents the results of electrolysis of tungsten oxygen-containing compounds in molten mixtures of NaCl, KCl, CaCl2 , NaF. Both the traditional reduction of tungsten from precursors (Na2W2O7 , Na3WO3F3) dissolved in the electrolyte and the deoxidation of the solid WO3 and CaWO4 (Cambridge FFC process) were used. Tungsten powders were obtained by potentiostatic electrolysis (potentials range -1 – -3 V) at 750 °C using solid Pt or liquid Ga cathodes and different electrolyte compositions. Detailed information is presented in [1-3]. Depending on the synthesis conditions and the electrolytes composition, dispersed (30–50 nm) tungsten powders with a current yield of 45–70% were obtained. It was established that the current efficiency and final product characteristics are affected by both standard electrolysis conditions (temperature, cathode potential, current density, etc.) and other conditions: tungsten precursors (the morphology of W obtained from Na2W2O7 is characterized by a well-ordered dendritic shape and from CaWO4 by a fibrous structure with spherical inclusions); cathode material (the use of a liquid Ga cathode improves the processes efficiency) and the mechanism of chemical and electrochemical reactions. Thus, the electrochemical synthesis in molten salts can become an alternative to traditional methods of tungsten obtaining. The optimization of the conditions of these processes will make it possible to synthesize of W-Co alloys or powders (coatings) of binary and ternary carbides.

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Canning, J., M. L. von Bibra e A. Roberts. "Mode Profile Modification of H Beam-Implanted Waveguides Using UV Processing". In Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/bgppf.1997.jma.6.

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UV photosensitivity in planar waveguides has primarily concentrated on the generation of sufficient oxygen-deficient centres using germanosilicate glass. There exists a wide range of methods fo fabricating such glasses, all with varying degrees of photosensitivity. Empirically, in planar waveguide at least, the degree of photosensitivity seems to be closely related to the defect induced losses such a increased Rayleigh scattering. For example, waveguides fabricated using flame hydrolysis exhibit very low propagation losses indicating a high level of purity of the glass. Consequently, this material requires sensitisation with hydrogen in order to achieve sizeable index changes with uv irradiation [1]. On the other hand, recent developments have allowed the demonstration of ultra-strong Bragg gratings in unsensitised PECVD-based glass [2], although at the expense of significantly higher propagation losses. A somewhat more impressive demonstration of photosensitivity has been the demonstration of direct waveguide writing with a mercury lamp in organically-derived glass using sol-gel methods [3]. By incorporating organic components into the glass silica polymer matrix, index change is achieved through polymerization of the organic ends which is a substantially different mechanism to that relying upon oxygen deficient centre absorptions. Low propagation losses, whilst maintaining a large photosensitivity, have been achieved this way. In addition to these materials, strong uv photosensitivity has also been observed in ion beam implanted material, mainly with Si2+ and Ge3+ implanted germanosilicate glass [4,5] although some work has been reported on changes in the uv spectra of H+ implanted germanosilicate waveguides [6].

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Fu, H., F. Dong, D. P. Sekulic, S. Dj Mesarovic e M. Krivilyov. "Surface Tension Driven Kinetics of the Triple Line of a Liquid Metal Free Surface". In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62945.

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Spreading kinetics of molten Al-Si alloy on both alumina and aluminum surfaces, driven by surface tension and retarded by viscosity, with or without significant impact of gravity, has been studied experimentally. Spreading takes place during a transient formation of the free liquid metal surface in a wedge-tee configuration corner between horizontal and vertical metal mating surfaces with a small Bo number. A high temperature optical dynamic contact angle measuring system has been used to monitor in real time in situ the free surface formation. Tests were performed under different oxygen concentration levels and at atmospheric pressure conditions, with a benchmark case involving ultra-high purity Nitrogen. An auxiliary study of the surface tension of the particular molten alloy considered has been performed under conditions of a large Bo number as well. These tests were performed over a flat non-wetting ceramic substrate of pure alumina (96%) using an optical sessile drop method. The former experiments resulted in capturing a 2-D configuration of the observed alloy liquid formation at elevated temperatures during a time evolution of the molten metal free surface spreading. The kinetics of the triple line movement at the vertical mating surface constitutes the main objective of the study. It is established that the triple line kinetics features a sequence of multiple, well defined spreading phases. These phases of the joint formation were identified, and the influential parameters were assessed. The power law spreading kinetics has been established. The experimental results show a good agreement with the hypothesized theoretical model.

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Hornung, Steven. "Spectroscopic Determination of Trace Contaminants in High Purity Oxygen". In 41st International Conference on Environmental Systems. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2011. http://dx.doi.org/10.2514/6.2011-5219.

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7

Jee, Jeong-Geun, Tae-Hoon Kwon e Chang-Ha Lee. "High Purity Oxygen Generation PSA Process by Using Carbon Molecular Sieve". In Proceedings of the Third Pacific Basin Conference. WORLD SCIENTIFIC, 2003. http://dx.doi.org/10.1142/9789812704320_0064.

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Hashimoto, Chisato, Hideo Oikawa e Nakahachiro Honma. "High Quality Ta2O5 Films Using Ultra-High Purity Ta Sputtering Target". In 1986 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 1986. http://dx.doi.org/10.7567/ssdm.1986.a-7-3.

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Velpula, Balaswamy, Harshitha S., Siddharth Ramachandran e V. R. Supradeepa. "High power, ultra-high spectral purity, broadly wavelength tunable cascaded Raman fiber laser". In Fiber Lasers XVI: Technology and Systems, a cura di Liang Dong e Adrian L. Carter. SPIE, 2019. http://dx.doi.org/10.1117/12.2510534.

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Alvarez, Dan, Jeffrey Spiegelman, Keisuke Andachi, Russell Holmes, Mark Raynor e Hank Shimizu. "Enabling low temperature Metal Nitride ALD using ultra-high purity hydrazine". In 2017 40th International Convention on Information and Communication Technology, Electronics and Microelectronics (MIPRO). IEEE, 2017. http://dx.doi.org/10.23919/mipro.2017.7966621.

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Rapporti di organizzazioni sul tema "Ultra high purity oxygen"

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Lucon, Enrico, Kenji Abiko, Marlies Lambrecht e Birgit Rehmer. Tensile Properties of Commercially Pure, High Purity and Ultra High Purity Iron: Results of an International Round-Robin. National Institute of Standards and Technology, aprile 2015. http://dx.doi.org/10.6028/nist.tn.1879.

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Veirs, Douglas, e Joshua Narlesky. Relative humidity threshold for oxygen generation by high-purity plutonium dioxides in 3013 containers. Office of Scientific and Technical Information (OSTI), ottobre 2023. http://dx.doi.org/10.2172/2204160.

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Tkac, P., S. Chemerisov, R. Gromov, T. Brossard, M. Virgo, K. Alford, K. Wesolowski, D. Rotsch e G. F. Vandegrift. Results of the Irradiation and Processing of Ultra-High Purity Sintered Natural Molybdenum Target Disks. Office of Scientific and Technical Information (OSTI), settembre 2017. http://dx.doi.org/10.2172/1433496.

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Tkac, Peter, Roman Gromov, Sergey D. Chemerisov, David A. Rotsch e George F. Vandegrift. Radiochemical purity of Mo and Tc solution obtained after irradiation and dissolution of Mo-100-enriched and ultra-high-purity natural Mo disks. Office of Scientific and Technical Information (OSTI), settembre 2016. http://dx.doi.org/10.2172/1342166.

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5

Li, Shiguang, e Miao Yu. Production of High-Purity O₂ via Membrane Contactor with Oxygen Carrier Solutions (Final Report). Office of Scientific and Technical Information (OSTI), dicembre 2017. http://dx.doi.org/10.2172/1512037.

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6

Simmons. L51814 Survey Of Dry Low NOx Combustor Experience. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), settembre 1999. http://dx.doi.org/10.55274/r0010207.

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Abstract (sommario):

Air pollution has become a major public issue and it is now evident that unburned hydrocarbons, CO, and NOx must meet increasingly restrictive standards. The emissions of nitrogen oxides by gas turbines are of concern because of their high toxicity and their role in the formation of photochemical smog. The formation of NOx occurs in a gas-fired gas turbine when combustion temperatures exceed a critical level for sufficient time to allow atmospheric nitrogen and oxygen to combine. For those gas turbine applications where steam or ultra-pure water are readily available, then steam or water injection are preferable NOx control strategies. Because these attributes are usually not available at pipeline compression stations, the turbine operators in the pipeline industry have chosen to control emissions by a dry combustion process. An alternative would be a catalytic reduction of the NOx generated in the exhaust gas but this requires an investment in SCR hardware and continuous use of ammonia, which adds to operating costs. Historically, dry low emissions (DLE) systems have experienced a greater than expected number of start-up problems as new products were introduced to the marketplace. A need of the gas pipeline industry is to identify the operating problems experienced with DLE systems, to link these problems to their most probable cause, to estimate costs incurred, and to glean strategies for avoiding future problems. A comprehensive PRCI sponsored survey of operators and manufacturers was completed which provides assistance to gas turbine operators in making NOx control procurement decisions and for budgeting operations and maintenance costs. This first ever detailed study provides information on typical operating costs and problems incurred with the currently operating DLE systems and serves as a guide for individual companies in the selection of cost effective low NOx combustion systems from available components offered by the OEM and after-market suppliers. The information developed by this report is intended to guide operators in estimating maintenance and repair costs to establish a lifetime cost of operation.

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