Microjets and coated wheels: versatile tools for exploring collisions and reactions at gas-liquid interfaces.

PubMed

Faust, Jennifer A; Nathanson, Gilbert M

2016-07-07

This tutorial review describes experimental aspects of two techniques for investigating collisions and reactions at the surfaces of liquids in vacuum. These gas-liquid scattering experiments provide insights into the dynamics of interfacial processes while minimizing interference from vapor-phase collisions. We begin with a historical survey and then compare attributes of the microjet and coated-wheel techniques, developed by Manfred Faubel and John Fenn, respectively, for studies of high- and low-vapor pressure liquids in vacuum. Our objective is to highlight the strengths and shortcomings of each technique and summarize lessons we have learned in using them for scattering and evaporation experiments. We conclude by describing recent microjet studies of energy transfer between O2 and liquid hydrocarbons, HCl dissociation in salty water, and super-Maxwellian helium evaporation.

Thermo-Rheometric Studies of New Class Ionic Liquid Lubricants

NASA Astrophysics Data System (ADS)

Bakhtiyarov, Sayavur; Street, Kenneth; Scheiman, Daniel; van Dyke, Alan

2010-11-01

Due to their specific properties, such as small volatility, nonflammability, extreme thermal stability, low melting point, wide liquid range, and good miscibility with organic materials, ionic liquids attracted particular interest in various industrial processes. Recently, the unique properties of ionic liquids caught the attention of space tribologists. The traditional lubricating materials used in space have limited lifetimes in vacuum due to the catalytic degradation on metal surfaces, high vaporization at high temperatures, dewetting, and other disadvantages. The lubricants for the space applications must have vacuum stability, high viscosity index, low creep tendency, good elastohydrodynamic and boundary lubrication properties, radiation atomic oxygen resistance, optical or infrared transparency. Unfortunately, the properties such as heat flow, heat capacity, thermogravimetric weight loss, and non-linearity in the rheological behavior of the lubricants are not studied well for newly developed systems. These properties are crucial to analyzing thermodynamic and energy dissipative aspects of the lubrication process. In this paper we will present the rheological and heat and mass transfer measurements for the ionic liquid lubricants, their mixtures with and without additive.

Systems and methods for analyzing liquids under vacuum

DOEpatents

Yu, Xiao-Ying; Yang, Li; Cowin, James P.; Iedema, Martin J.; Zhu, Zihua

2013-10-15

Systems and methods for supporting a liquid against a vacuum pressure in a chamber can enable analysis of the liquid surface using vacuum-based chemical analysis instruments. No electrical or fluid connections are required to pass through the chamber walls. The systems can include a reservoir, a pump, and a liquid flow path. The reservoir contains a liquid-phase sample. The pump drives flow of the sample from the reservoir, through the liquid flow path, and back to the reservoir. The flow of the sample is not substantially driven by a differential between pressures inside and outside of the liquid flow path. An aperture in the liquid flow path exposes a stable portion of the liquid-phase sample to the vacuum pressure within the chamber. The radius, or size, of the aperture is less than or equal to a critical value required to support a meniscus of the liquid-phase sample by surface tension.

Resin impregnation process for producing a resin-fiber composite

NASA Technical Reports Server (NTRS)

Palmer, Raymond J. (Inventor); Moore, William E. (Inventor)

1994-01-01

Process for vacuum impregnation of a dry fiber reinforcement with a curable resin to produce a resin-fiber composite, by drawing a vacuum to permit flow of curable liquid resin into and through a fiber reinforcement to impregnate same and curing the resin-impregnated fiber reinforcement at a sufficient temperature and pressure to effect final curing. Both vacuum and positive pressure, e.g. autoclave pressure, are applied to the dry fiber reinforcement prior to application of heat and prior to any resin flow to compact the dry fiber reinforcement, and produce a resin-fiber composite of reduced weight, thickness and resin content, and improved mechanical properties. Preferably both a vacuum and positive pressure, e.g. autoclave pressure, are also applied during final curing.

Patterned Liquid Metal Contacts for Printed Carbon Nanotube Transistors.

PubMed

Andrews, Joseph B; Mondal, Kunal; Neumann, Taylor V; Cardenas, Jorge A; Wang, Justin; Parekh, Dishit P; Lin, Yiliang; Ballentine, Peter; Dickey, Michael D; Franklin, Aaron D

2018-05-14

Flexible and stretchable electronics are poised to enable many applications that cannot be realized with traditional, rigid devices. One of the most promising options for low-cost stretchable transistors are printed carbon nanotubes (CNTs). However, a major limiting factor in stretchable CNT devices is the lack of a stable and versatile contact material that forms both the interconnects and contact electrodes. In this work, we introduce the use of eutectic gallium-indium (EGaIn) liquid metal for electrical contacts to printed CNT channels. We analyze thin-film transistors (TFTs) fabricated using two different liquid metal deposition techniques-vacuum-filling polydimethylsiloxane (PDMS) microchannel structures and direct-writing liquid metals on the CNTs. The highest performing CNT-TFT was realized using vacuum-filled microchannel deposition with an in situ annealing temperature of 150 °C. This device exhibited an on/off ratio of more than 10 4 and on-currents as high as 150 μA/mm-metrics that are on par with other printed CNT-TFTs. Additionally, we observed that at room temperature the contact resistances of the vacuum-filled microchannel structures were 50% lower than those of the direct-write structures, likely due to the poor adhesion between the materials observed during the direct-writing process. The insights gained in this study show that stretchable electronics can be realized using low-cost and solely solution processing techniques. Furthermore, we demonstrate methods that can be used to electrically characterize semiconducting materials as transistors without requiring elevated temperatures or cleanroom processes.

Application of ionic liquids in vacuum microwave-assisted extraction followed by macroporous resin isolation of three flavonoids rutin, hyperoside and hesperidin from Sorbus tianschanica leaves.

PubMed

Gu, Huiyan; Chen, Fengli; Zhang, Qiang; Zang, Jing

2016-03-01

Rutin, hyperoside and hesperidin were effectively extracted from Sorbus tianschanica leaves by an ionic liquid vacuum microwave-assisted method. A series of ionic liquids with various anions and alkyl chain length of the cations were studied and the extraction was performed in [C6mim][BF4] aqueous solution. After optimization by a factorial design and response surface methodology, total extraction yield of 2.37mg/g with an error of 0.12mg/g (0.71±0.04mg/g, 1.18±0.06mg/g and 0.48±0.02 for rutin, hyperoside and hesperidin, respectively) was achieved under -0.08MPa for vacuum, 19min and 420W for microwave irradiation time and power, and 15mL/g for liquid-solid ratio. The proposed method here is more efficient and needs a shorter extraction time for rutin, hyperoside and hesperidin from S. tianschanica leaves than reference extraction techniques. In stability studies performed with standard rutin, hyperoside and hesperidin, the target analytes were stable under the optimum conditions. The proposed method had a high reproducibility and precision. In addition, separation of rutin, hyperoside and hesperidin from [C6mim][BF4] extraction solution was completed effectively by AB-8 macroporous resin adsorption and desorption process. Ionic liquid vacuum microwave-assisted extraction is a simple, rapid and efficient sample extraction technique. Copyright © 2016 Elsevier B.V. All rights reserved.

Modeling study on the flow patterns of gas-liquid flow for fast decarburization during the RH process

NASA Astrophysics Data System (ADS)

Li, Yi-hong; Bao, Yan-ping; Wang, Rui; Ma, Li-feng; Liu, Jian-sheng

2018-02-01

A water model and a high-speed video camera were utilized in the 300-t RH equipment to study the effect of steel flow patterns in a vacuum chamber on fast decarburization and a superior flow-pattern map was obtained during the practical RH process. There are three flow patterns with different bubbling characteristics and steel surface states in the vacuum chamber: boiling pattern (BP), transition pattern (TP), and wave pattern (WP). The effect of the liquid-steel level and the residence time of the steel in the chamber on flow patterns and decarburization reaction were investigated, respectively. The liquid-steel level significantly affected the flow-pattern transition from BP to WP, and the residence time and reaction area were crucial to evaluate the whole decarburization process rather than the circulation flow rate and mixing time. A superior flow-pattern map during the practical RH process showed that the steel flow pattern changed from BP to TP quickly, and then remained as TP until the end of decarburization.

Investigation of low cost material processes for liquid rocket engines

NASA Technical Reports Server (NTRS)

Nguyentat, Thinh; Kawashige, Chester M.; Scala, James G.; Horn, Ronald M.

1993-01-01

The development of low cost material processes is essential to the achievement of economical liquid rocket propulsion systems in the next century. This paper will present the results of the evaluation of some promising material processes including powder metallurgy, vacuum plasma spray, metal spray forming, and bulge forming. The physical and mechanical test results from the samples and subscale hardware fabricated from high strength copper alloys and superalloys will be discussed.

Molecular Beam Studies of Volatile Liquids and Fuel Surrogates Using Liquid MICR

DTIC Science & Technology

2014-12-23

Detailed discussions of the microjet technique are carried out in the following publications. Nozzle Liquid Jet Chopper Wheel Cold Collector Cold...process is shown in the picture below; heating and evaporation occur within 1 ms of fuel leaving the fuel injector . This atomization proves is often...liquid jet. This analysis leads to criteria for selecting the temperature and nozzle radius for producing stable jets in vacuum. Figure 4 depicts the

Cyclic membrane separation process

DOEpatents

Nemser, Stuart M.

2005-05-03

A cyclic process for controlling environmental emissions of volatile organic compounds (VOC) from vapor recovery in storage and dispensing operations of liquids maintains a vacuum in the storage tank ullage. In the first part of a two-part cyclic process ullage vapor is discharged through a vapor recovery system in which VOC are stripped from vented gas with a selectively gas permeable membrane. In the second part, the membrane is inoperative while gas pressure rises in the ullage. In one aspect of this invention, a vacuum is drawn in the membrane separation unit thus reducing overall VOC emissions.

Wireless Integrated Microelectronic Vacuum Sensor System

NASA Technical Reports Server (NTRS)

Krug, Eric; Philpot, Brian; Trott, Aaron; Lawrence, Shaun

2013-01-01

NASA Stennis Space Center's (SSC's) large rocket engine test facility requires the use of liquid propellants, including the use of cryogenic fluids like liquid hydrogen as fuel, and liquid oxygen as an oxidizer (gases which have been liquefied at very low temperatures). These fluids require special handling, storage, and transfer technology. The biggest problem associated with transferring cryogenic liquids is product loss due to heat transfer. Vacuum jacketed piping is specifically designed to maintain high thermal efficiency so that cryogenic liquids can be transferred with minimal heat transfer. A vacuum jacketed pipe is essentially two pipes in one. There is an inner carrier pipe, in which the cryogenic liquid is actually transferred, and an outer jacket pipe that supports and seals the vacuum insulation, forming the "vacuum jacket." The integrity of the vacuum jacketed transmission lines that transfer the cryogenic fluid from delivery barges to the test stand must be maintained prior to and during engine testing. To monitor the vacuum in these vacuum jacketed transmission lines, vacuum gauge readings are used. At SSC, vacuum gauge measurements are done on a manual rotation basis with two technicians, each using a handheld instrument. Manual collection of vacuum data is labor intensive and uses valuable personnel time. Additionally, there are times when personnel cannot collect the data in a timely fashion (i.e., when a leak is detected, measurements must be taken more often). Additionally, distribution of this data to all interested parties can be cumbersome. To simplify the vacuum-gauge data collection process, automate the data collection, and decrease the labor costs associated with acquiring these measurements, an automated system that monitors the existing gauges was developed by Invocon, Inc. For this project, Invocon developed a Wireless Integrated Microelectronic Vacuum Sensor System (WIMVSS) that provides the ability to gather vacuum-gauge measurements automatically and wirelessly, in near-real time - using a low-maintenance, lowpower sensor mesh network. The WIMVSS operates by using a self-configuring mesh network of wireless sensor units. Mesh networking is a type of networking where each sensor or node can capture and disseminate its own data, but also serve as a relay to receive and transmit data from other sensors. Each sensor node can synchronize with adjacent sensors, and propagate data from one sensor to the next, until the destination is reached. In this case, the destination is a Network Interface Unit (NIU). The WIMVSS sensors are mounted on the existing vacuum gauges. Information gathered by the sensors is sent to the NIU. Because of the mesh networking, if a sensor cannot directly send the data to the NIU, it can be propagated through the network of sensors. The NIU requires antenna access to the sensor units, AC power, and an Ethernet connection. The NIU bridges the sensor network to a WIMVSS server via an Ethernet connection. The server is configured with a database, a Web server, and proprietary interface software that makes it possible for the vacuum measurements from vacuum jacketed fluid lines to be saved, retrieved, and then displayed from any Web-enabled PC that has access to the Internet. Authorized users can then simply access the data from any PC with Internet connection. Commands can also be sent directly from the Web interface for control and maintenance of the sensor network. The technology enabled by the WIMVSS decreases labor required for gathering vacuum measurements, increases access to vacuum data by making it available on any computer with access to the Internet, increases the frequency with which data points can be acquired for evaluating the system, and decreases the recurring cost of the sensors by using off-the-shelf components and integrating these with heritage vacuum gauges.

Microfluidic electrochemical device and process for chemical imaging and electrochemical analysis at the electrode-liquid interface in-situ

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Xiao-Ying; Liu, Bingwen; Yang, Li

2016-03-01

A microfluidic electrochemical device and process are detailed that provide chemical imaging and electrochemical analysis under vacuum at the surface of the electrode-sample or electrode-liquid interface in-situ. The electrochemical device allows investigation of various surface layers including diffuse layers at selected depths populated with, e.g., adsorbed molecules in which chemical transformation in electrolyte solutions occurs.

Effect of vacuum and of strong adsorbed water films on micropore formation in aluminum hydroxide xerogel powders.

PubMed

Beruto, Dario T; Botter, Rodolfo; Converti, Attilio

2009-02-01

Aluminum hydroxide gels were washed with water, ethanol, methanol and isopropanol to obtain new gels with different liquid phases that were dried either in air at 120 degrees C or under vacuum at 80 degrees C. Drying in air leads to alcoholic xerogels with BET surface areas larger than the aqueous ones. The effect of the alcoholic groups as substitutes of the hydroxyl ones has been discussed to account for the final size of xerogel crystallites. Drying under vacuum decreases the BET surface of the methanol xerogels, but no micropores are formed in all the alcoholic xerogel matrixes. On the contrary, the vacuum drying process changes significantly the microstructure of the aqueous xerogels. Their BET surface increases by 34 m(2)/g, and micropores are formed within their crystallite aggregates. It has been experimentally shown that these changes are due to a shear transformation that occurs in the boehmite xerogels obtained under vacuum. To discuss these data, the existence of chemical compounds such as AlOOHnH(2)O was postulated. On this ground, a neat analogy between vacuum drying process and vacuum interfacial decomposition reactions of inorganic salts can be drawn. This analogy explains how a state of stresses forms in aqueous xerogel matrix during vacuum drying process.

On-line comprehensive two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography for preparative isolation of toad venom.

PubMed

Li, Jia-Fu; Fang, Hua; Yan, Xia; Chang, Fang-Rong; Wu, Zhen; Wu, Yun-Long; Qiu, Ying-Kun

2016-07-22

An on-line comprehensive preparative two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography (2D NPLC×RPLC) system was constructed with a newly developed vacuum evaporation assisted adsorption (VEAA) interface, allowing fast removal of NPLC solvent in the vacuum condition and successfully solving the solvent incompatibility problem between NPLC and RPLC. The system achieved on-line solvent exchange within the two dimensions and its performance was illustrated by gram-scale isolation of crude extract from the venom of Bufo bufo gargarizans. Within separation time of ∼20h, 19 compounds were obtained with high purity in a single run. With the VEAA interface, the 2D system exhibited apparent advantages in separation efficiency and automation compared with conventional methods, indicating its promising application in the routine separation process for complicated natural products. Copyright © 2016 Elsevier B.V. All rights reserved.

Sensor-model prediction, monitoring and in-situ control of liquid RTM advanced fiber architecture composite processing

NASA Technical Reports Server (NTRS)

Kranbuehl, D.; Kingsley, P.; Hart, S.; Loos, A.; Hasko, G.; Dexter, B.

1992-01-01

In-situ frequency dependent electromagnetic sensors (FDEMS) and the Loos resin transfer model have been used to select and control the processing properties of an epoxy resin during liquid pressure RTM impregnation and cure. Once correlated with viscosity and degree of cure the FDEMS sensor monitors and the RTM processing model predicts the reaction advancement of the resin, viscosity and the impregnation of the fabric. This provides a direct means for predicting, monitoring, and controlling the liquid RTM process in-situ in the mold throughout the fabrication process and the effects of time, temperature, vacuum and pressure. Most importantly, the FDEMS-sensor model system has been developed to make intelligent decisions, thereby automating the liquid RTM process and removing the need for operator direction.

Molecular Beam Studies of Volatile Liquids and Fuel Surrogates Using Liquid Microjets

DTIC Science & Technology

2014-12-18

themselves. Detailed discussions of the microjet technique are carried out in the following publications. Nozzle Liquid Jet Chopper Wheel...heating and evaporation occur within 1 ms of fuel leaving the fuel injector . This atomization proves is often the limiting process in combustion...This analysis leads to criteria for selecting the temperature and nozzle radius for producing stable jets in vacuum. Figure 4 depicts the

Coal liquefaction process

DOEpatents

Wright, Charles H.

1986-01-01

A process for the liquefaction of coal wherein raw feed coal is dissolved in recycle solvent with a slurry containing recycle coal minerals in the presence of added hydrogen at elevated temperature and pressure. The highest boiling distillable dissolved liquid fraction is obtained from a vacuum distillation zone and is entirely recycled to extinction. Lower boiling distillable dissolved liquid is removed in vapor phase from the dissolver zone and passed without purification and essentially without reduction in pressure to a catalytic hydrogenation zone where it is converted to an essentially colorless liquid product boiling in the transportation fuel range.

A study of LC-39 cryogenic systems. Part 1: A study of the vacuum insulated transfer lines at Kennedy Space Center. Part 2: Cooldown pressure surges

NASA Technical Reports Server (NTRS)

Ludtke, P. R.; Voth, R. O.

1971-01-01

The vacuum liquid hydrogen and liquid oxygen transfer lines at Kennedy Space Center were studied to evaluate the feasibility of using a condensing gas such as CO2 inside the vacuum spaces to achieve a condensing-vacuum. The study indicates that at ambient temperature, a maximum vacuum hyphen space pressure of 4000 microns is acceptable for the LH2 transfer lines. In addition, the cooldown procedures for the 14-inch cross-country liquid oxygen line was studied using a simplified mathematical model. Preliminary cooldown times are presented for various heat leak rates to the line and for two vent configurations.

46 CFR 32.55-30 - Venting of cargo tanks of tank vessels constructed between November 10, 1936, and July 1, 1951-TB...

Code of Federal Regulations, 2011 CFR

2011-10-01

... carrying Grade A liquids, separate discharge pipes may be fitted to each pressure-vacuum relief valve, or... which Grade B or C liquids are to be transported shall be fitted with individual pressure-vacuum relief... arrester or a pressure-vacuum relief valve. (d) Grade D or E liquids. Cargo tanks in which Grade D or E...

46 CFR 32.55-30 - Venting of cargo tanks of tank vessels constructed between November 10, 1936, and July 1, 1951-TB...

Code of Federal Regulations, 2012 CFR

2012-10-01

... carrying Grade A liquids, separate discharge pipes may be fitted to each pressure-vacuum relief valve, or... which Grade B or C liquids are to be transported shall be fitted with individual pressure-vacuum relief... arrester or a pressure-vacuum relief valve. (d) Grade D or E liquids. Cargo tanks in which Grade D or E...

46 CFR 32.55-30 - Venting of cargo tanks of tank vessels constructed between November 10, 1936, and July 1, 1951-TB...

Code of Federal Regulations, 2010 CFR

2010-10-01

... carrying Grade A liquids, separate discharge pipes may be fitted to each pressure-vacuum relief valve, or... which Grade B or C liquids are to be transported shall be fitted with individual pressure-vacuum relief... arrester or a pressure-vacuum relief valve. (d) Grade D or E liquids. Cargo tanks in which Grade D or E...

46 CFR 32.55-30 - Venting of cargo tanks of tank vessels constructed between November 10, 1936, and July 1, 1951-TB...

Code of Federal Regulations, 2014 CFR

2014-10-01

... carrying Grade A liquids, separate discharge pipes may be fitted to each pressure-vacuum relief valve, or... which Grade B or C liquids are to be transported shall be fitted with individual pressure-vacuum relief... arrester or a pressure-vacuum relief valve. (d) Grade D or E liquids. Cargo tanks in which Grade D or E...

46 CFR 32.55-30 - Venting of cargo tanks of tank vessels constructed between November 10, 1936, and July 1, 1951-TB...

Code of Federal Regulations, 2013 CFR

2013-10-01

... carrying Grade A liquids, separate discharge pipes may be fitted to each pressure-vacuum relief valve, or... which Grade B or C liquids are to be transported shall be fitted with individual pressure-vacuum relief... arrester or a pressure-vacuum relief valve. (d) Grade D or E liquids. Cargo tanks in which Grade D or E...

Process-time Optimization of Vacuum Degassing Using a Genetic Alloy Design Approach

PubMed Central

Dilner, David; Lu, Qi; Mao, Huahai; Xu, Wei; van der Zwaag, Sybrand; Selleby, Malin

2014-01-01

This paper demonstrates the use of a new model consisting of a genetic algorithm in combination with thermodynamic calculations and analytical process models to minimize the processing time during a vacuum degassing treatment of liquid steel. The model sets multiple simultaneous targets for final S, N, O, Si and Al levels and uses the total slag mass, the slag composition, the steel composition and the start temperature as optimization variables. The predicted optimal conditions agree well with industrial practice. For those conditions leading to the shortest process time the target compositions for S, N and O are reached almost simultaneously. PMID:28788286

Radioactive scrap metal decontamination technology assessment report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buckentin, J.M.; Damkroger, B.K.; Schlienger, M.E.

1996-04-01

Within the DOE complex there exists a tremendous quantity of radioactive scrap metal. As an example, it is estimated that within the gaseous diffusion plants there exists in excess of 700,000 tons of contaminated stainless steel. At present, valuable material is being disposed of when it could be converted into a high quality product. Liquid metal processing represents a true recycling opportunity for this material. By applying the primary production processes towards the material`s decontamination and re-use, the value of the strategic resource is maintained while drastically reducing the volume of material in need of burial. Potential processes for themore » liquid metal decontamination of radioactively contaminated metal are discussed and contrasted. Opportunities and technology development issues are identified and discussed. The processes compared are: surface decontamination; size reduction, packaging and burial; melting technologies; electric arc melting; plasma arc centrifugal treatment; air induction melting; vacuum induction melting; and vacuum induction melting and electroslag remelting.« less

Degradation kinetics of cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside during hot air and vacuum drying in mulberry (Morus alba L.) fruit: A comparative study based on solid food system.

PubMed

Zhou, Mo; Chen, Qinqin; Bi, Jinfeng; Wang, Yixiu; Wu, Xinye

2017-08-15

The aim of this study is to ascertain the degradation kinetic of anthocyanin in dehydration process of solid food system. Mulberry fruit was treated by hot air and vacuum drying at 60 and 75°C. The contents of cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside were determined by using high performance liquid chromatography. Kinetic and thermodynamic parameters were calculated for analysing the degradation characteristics. Model fitting results showed monomeric anthocyanin degradations were followed the second-order kinetic. Vacuum drying presented high kinetic rate constants and low t 1/2 values. Thermodynamic parameters including the activation energy, enthalpy change and entropy change appeared significant differences between hot air and vacuum drying. Both heating techniques showed similar effects on polyphenol oxidase activities. These results indicate the anthocyanin degradation kinetic in solid food system is different from that in liquid and the oxygen can be regarded as a catalyst to accelerate the degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

A review of the use of Al-alloy vacuum components for operation at 10-13 Torr

NASA Astrophysics Data System (ADS)

Ishimaru, Hajime

1990-02-01

An extremely high vacuum (XHV) chamber was fabricated and tested. The vacuum chamber was made of special surface finished (EX-process) aluminum alloy in oxygen and argon atmosphere. The chamber was assembled using TIG welding in an argon atmosphere and by electron beam welding. The system was evacuated with a turbo-backed 300 l/s turbomolecular pump separated from the main chamber using a right angle valve. The liquid nitrogen shroud is installed inside the main vacuum chamber. The XHV is maintained by two 300 l/s sputter ion pumps and a titanium sublimation pump with a liquid nitrogen shroud. These pumps are also made of aluminum alloys. An ultimate pressure of 3×10-13 Torr was measured with a point collector gauge with a spherical anode mounted on an Al-flange. Residual gas analysis in the order 10-13 Torr was performed by a newly developed Q-mass filter. To suppress outgassing from the quadrupole electrode, the ion source is mounted on an Al-flange separated from the quadrupole electrode.

Coal liquefaction process

DOEpatents

Wright, C.H.

1986-02-11

A process is described for the liquefaction of coal wherein raw feed coal is dissolved in recycle solvent with a slurry containing recycle coal minerals in the presence of added hydrogen at elevated temperature and pressure. The highest boiling distillable dissolved liquid fraction is obtained from a vacuum distillation zone and is entirely recycled to extinction. Lower boiling distillable dissolved liquid is removed in vapor phase from the dissolver zone and passed without purification and essentially without reduction in pressure to a catalytic hydrogenation zone where it is converted to an essentially colorless liquid product boiling in the transportation fuel range. 1 fig.

Cooling and solidification of heavy hydrocarbon liquid streams

DOEpatents

Antieri, Salvatore J.; Comolli, Alfred G.

1983-01-01

A process and apparatus for cooling and solidifying a stream of heavy hydrocarbon material normally boiling above about 850.degree. F., such as vacuum bottoms material from a coal liquefaction process. The hydrocarbon stream is dropped into a liquid bath, preferably water, which contains a screw conveyor device and the stream is rapidly cooled, solidified and broken therein to form discrete elongated particles. The solid extrudates or prills are then dried separately to remove substantially all surface moisture, and passed to further usage.

Micrometer-thickness liquid sheet jets flowing in vacuum

NASA Astrophysics Data System (ADS)

Galinis, Gediminas; Strucka, Jergus; Barnard, Jonathan C. T.; Braun, Avi; Smith, Roland A.; Marangos, Jon P.

2017-08-01

Thin liquid sheet jet flows in vacuum provide a new platform for performing experiments in the liquid phase, for example X-ray spectroscopy. Micrometer thickness, high stability, and optical flatness are the key characteristics required for successful exploitation of these targets. A novel strategy for generating sheet jets in vacuum is presented in this article. Precision nozzles were designed and fabricated using high resolution (0.2 μm) 2-photon 3D printing and generated 1.49 ± 0.04 μm thickness, stable, and <λ /20-flat jets in isopropanol under normal atmosphere and under vacuum at 5 × 10-1 mbar. The thin sheet technology also holds great promise for advancing the fields of high harmonic generation in liquids, laser acceleration of ions as well as other fields requiring precision and high repetition rate targets.

Denitrogenation model for vacuum tank degasser

NASA Astrophysics Data System (ADS)

Gobinath, R.; Vetrivel Murugan, R.

2018-02-01

Nitrogen in steel is both beneficial and detrimental depending on grade of steel and its application. To get desired low nitrogen during vacuum degassing process, VD parameters namely vacuum level, argon flow rate and holding time has to optimized depending upon initial nitrogen level. In this work a mathematical model to simulate nitrogen removal in tank degasser is developed and how various VD parameters affects nitrogen removal is studied. Ladle water model studies with bottom purging have shown two distinct flow regions, namely the plume region and the outside plume region. The two regions are treated as two separate reactors exchanging mass between them and complete mixing is assumed in both the reactors. In the plume region, transfer of nitrogen to single bubble is simulated. At the gas-liquid metal interface (bubble interface) thermodynamic equilibrium is assumed and the transfer of nitrogen from bulk liquid metal in the plume region to the gas-metal interface is obtained using mass transport principles. The model predicts variation of Nitrogen content in both the reactors with time. The model is validated with industrial process and the predicted results were found to have fair agreement with the measured results.

The Safe and Efficient Evaporation of a Solvent from Solution

NASA Astrophysics Data System (ADS)

Mahon, Andrew R.

1997-02-01

The process of evaporating a solvent from a solution can cause problems for many students. By using a water-vacuum aspirator, backflashes of water can flood the sample tube and be detrimental to the experiment. This type of apparatus can also cause problems by drawing the solution it is evaporating back into the vacuum hose, causing the student to lose part or all of the products of their experiment. Macroscale and Microscale Organic Experiments, 2nd edition (1), suggested two techniques to dissolve solvents from a mixture. It suggested blowing a stream of air over the solution from a Pasteur pipet, or attaching a Pasteur pipet to an aspirator and drawing air over the surface of the liquid. Again, the danger of blowing air over the solution leaves the risk of splattering the solution, and drawing air over the surface of the liquid as described further endangers the products of the experiment through the risk of sucking the products up into the pipet aspirator. In an effort to eliminate these problems, a new technique has been developed. By inverting an ordinary 200-mL vacuum flask and pulling a steady current of air from the vacuum apparatus through it, any type of small container can be placed under it, allowing the solvent to be evaporated in a steady, mistake-free manner . By evaporating the solvent from the container that the products will be submitted in, no sample is lost through the process of transferring it from a vacuum flask or beaker to the final container.

Quantitative study of sniffer leak rate and pressure drop leak rate of liquid nitrogen panels of SST-1 tokamak

NASA Astrophysics Data System (ADS)

Pathan, F. S.; Khan, Z.; Semwal, P.; Raval, D. C.; Joshi, K. S.; Thankey, P. L.; Dhanani, K. R.

2008-05-01

Steady State Super-conducting (SST-1) Tokamak is in commissioning stage at Institute for Plasma Research. Vacuum chamber of SST-1 Tokamak consists of 1) Vacuum vessel, an ultra high vacuum (UHV) chamber, 2) Cryostat, a high vacuum (HV) chamber. Cryostat encloses the liquid helium cooled super-conducting magnets (TF and PF), which require the thermal radiation protection against room temperature. Liquid nitrogen (LN2) cooled panels are used to provide thermal shield around super-conducting magnets. During operation, LN2 panels will be under pressurized condition and its surrounding (cryostat) will be at high vacuum. Hence, LN2 panels must have very low leak rate. This paper describes an experiment to study the behaviour of the leaks in LN2 panels during sniffer test and pressure drop test using helium gas.

49 CFR 173.318 - Cryogenic liquids in cargo tanks.

Code of Federal Regulations, 2012 CFR

2012-10-01

....338-15). (3) The jacket covering the insulation on a tank used to transport a cryogenic liquid must be... devices for piping hose and vacuum-insulated jackets. (i) Each portion of connected liquid piping or hose... tank, piping, or operating personnel. (ii) On a vacuum-insulated cargo tank the jacket must be...

Fine tuning the ionic liquid-vacuum outer atomic surface using ion mixtures.

PubMed

Villar-Garcia, Ignacio J; Fearn, Sarah; Ismail, Nur L; McIntosh, Alastair J S; Lovelock, Kevin R J

2015-03-28

Ionic liquid-vacuum outer atomic surfaces can be created that are remarkably different from the bulk composition. In this communication we demonstrate, using low-energy ion scattering (LEIS), that for ionic liquid mixtures the outer atomic surface shows significantly more atoms from anions with weaker cation-anion interactions (and vice versa).

Vacuum Plasma Spray Forming of Copper Alloy Liners for Regeneratively Cooled Liquid Rocket Combustion Chambers

NASA Technical Reports Server (NTRS)

Zimmerman, Frank

2003-01-01

Vacuum plasma spray (VPS) has been demonstrated as a method to form combustion chambers from copper alloys NARloy-Z and GRCop-84. Vacuum plasma spray forming is of particular interest in the forming of CuCrNb alloys such as GRCop-84, developed by NASA s Glenn Research Center, because the alloy cannot be formed using conventional casting and forging methods. This limitation is related to the levels of chromium and niobium in the alloy, which exceed the solubility limit in copper. Until recently, the only forming process that maintained the required microstructure of CrNb intermetallics was powder metallurgy formation of a billet from powder stock, followed by extrusion. This severely limits its usefulness in structural applications, particularly the complex shapes required for combustion chamber liners. This paper discusses the techniques used to form combustion chambers from CuCrNb and NARloy-Z, which will be used in regeneratively cooled liquid rocket combustion chambers.

Open loop, auto reversing liquid nitrogen circulation thermal system for thermo vacuum chamber

NASA Astrophysics Data System (ADS)

Naidu, M. C. A.; Nolakha, Dinesh; Saharkar, B. S.; Kavani, K. M.; Patel, D. R.

2012-11-01

In a thermo vacuum chamber, attaining and controlling low and high temperatures (-100 Deg. C to +120 Deg. C) is a very important task. This paper describes the development of "Open loop, auto reversing liquid nitrogen based thermal system". System specifications, features, open loop auto reversing system, liquid nitrogen flow paths etc. are discussed in this paper. This thermal system consists of solenoid operated cryogenic valves, double embossed thermal plate (shroud), heating elements, temperature sensors and PLC. Bulky items like blowers, heating chambers, liquid nitrogen injection chambers, huge pipe lines and valves were not used. This entire thermal system is very simple to operate and PLC based, fully auto system with auto tuned to given set temperatures. This system requires a very nominal amount of liquid nitrogen (approx. 80 liters / hour) while conducting thermo vacuum tests. This system was integrated to 1.2m dia thermo vacuum chamber, as a part of its augmentation, to conduct extreme temperature cycling tests on passive antenna reflectors of satellites.

Short communication: Effects of vacuum freeze-drying on inactivation of Cronobacter sakazakii ATCC29544 in liquid media with different initial inoculum levels.

PubMed

Jiao, Rui; Gao, Jina; Zhang, Xiyan; Zhang, Maofeng; Chen, Jiren; Wu, Qingping; Zhang, Jumei; Ye, Yingwang

2017-03-01

Vacuum freeze-drying is an important food-processing technology for valid retention of nutrients and bioactive compounds. Cronobacter sakazakii has been reported to be associated with severe infections in neonates through consumption of contaminated powdered infant formula. In this study, effects of vacuum freeze-drying treatment for 12, 24, and 36 h on inactivation of C. sakazakii with different initial inoculum levels in sterile water, tryptic soy broth (TSB), skim milk, and whole milk were determined. Results indicated that the lethality rate of C. sakazakii in each sample increased with the extension of vacuum freeze-drying time. With initial inoculum levels of 10 2 and 10 3 cfu/mL, the survival of C. sakazakii in different liquid media was significantly affected by vacuum freeze-drying for 12, 24, and 36 h. In addition, the lethality rates of C. sakazakii in whole milk, skim milk, and TSB was significantly reduced compared with those in sterile water. Furthermore, whole milk showed the strongest protective role for C. sakazakii cells, followed by skim milk and TSB medium. Using the scanning electron microscope, the intracellular damage and obvious distortion of C. sakazakii cells were observed after vacuum freeze-drying for 24 and 36 h compared with the untreated sample, and the injured cells increased with the extension of vacuum-drying time. We concluded that inactivation of vacuum freeze-drying on C. sakazakii cells is related to the food matrix, and a combination with other methods for inactivating C. sakazakii is required for ensuring microbial safety of powdered infant formula. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Triggering vacuum capillaries for pneumatic pumping and metering liquids in point-of-care immunoassays.

PubMed

Weng, Kuo-Yao; Chou, Nien-Jen; Cheng, Jya-Wei

2008-07-01

An innovative vacuum capillary pneumatic actuation concept that can be used for point-of-care testing has been investigated. The vacuum glass capillaries are encapsulated within a laminated pouch and incorporated into the fluidic card. Vacuum glass capillaries broken by external force such as finger pressure, generate the pneumatic forces to induce liquid flow in the fluidic system. The sizes of vacuum capillary play a vital role in the pumping and metering functions of the system. The luteinizing hormone (LH) chromatographic immunoassay performances in the fluidic cards show consistency comparable to that obtained by manual micropipetting. The vacuum capillary pneumatic actuation will be applied in other complex handling step bioassays and lab-on-a-chip devices.

Kinetic and Mechanistic Study of Vapor-Phase Free Radical Polymerization onto Liquid Surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Malancha

The primary objective of this proposal was to study vapor deposition of polymers onto liquid surfaces. Deposition onto liquid surfaces is a relatively new area of research because the past few decades have focused on deposition onto solid materials. We used initiated chemical vapor deposition to deposit polymers onto the liquid surfaces. The process is a one-step, solventless, free-radical polymerization process in which monomer and initiator molecules are flowed into a vacuum chamber. We found that the surface tension interaction between the polymer and the liquid determines whether a film or nanoparticles are formed. We also found that we couldmore » form gels by using soluble monomers. We found that we could tune the size of the nanoparticles by varying the viscosity of the liquid and the process parameters including pressure and time. These insights allow scalable synthesis of polymer materials for a variety of separation and catalysis applications.« less

Composite aerogel insulation for cryogenic liquid storage

NASA Astrophysics Data System (ADS)

Kyeongho, Kim; Hyungmook, Kang; Soojin, Shin; In Hwan, Oh; Changhee, Son; Hyung, Cho Yun; Yongchan, Kim; Sarng Woo, Karng

2017-02-01

High porosity materials such as aerogel known as a good insulator in a vacuum range (10-3 ∼ 1 Torr) was widely used to storage and to transport cryogenic fluids. It is necessary to be investigated the performance of aerogel insulations for cryogenic liquid storage in soft vacuum range to atmospheric pressure. A one-dimensional insulating experimental apparatus was designed and fabricated to consist of a cold mass tank, a heat absorber and an annular vacuum space with 5-layer (each 10 mm thickness) of the aerogel insulation materials. Aerogel blanket for cryogenic (used maximum temperature is 400K), aerogel blanket for normal temperature (used maximum temperature is 923K), and combination of the two kinds of aerogel blankets were 5-layer laminated between the cryogenic liquid wall and the ambient wall in vacuum space. Also, 1-D effective thermal conductivities of the insulation materials were evaluated by measuring boil-off rate from liquid nitrogen and liquid argon. In this study, the effective thermal conductivities and the temperature-thickness profiles of the two kinds of insulators and the layered combination of the two different aerogel blankets were presented.

Deformation of contact surfaces in a vacuum interrupter after high-current interruptions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Haoran; Wang, Zhenxing, E-mail: zxwang@xjtu.edu.cn; Zhou, Zhipeng

2016-08-07

In a high-current interruption, the contact surface in a vacuum interrupter might be severely damaged by constricted vacuum arcs causing a molten area on it. As a result, a protrusion will be initiated by a transient recovery voltage after current zero, enhancing the local electric field and making breakdowns occur easier. The objective of this paper is to simulate the deformation process on the molten area under a high electric field by adopting the finite element method. A time-dependent Electrohydrodynamic model was established, and the liquid-gas interface was tracked by the level-set method. From the results, the liquid metal canmore » be deformed to a Taylor cone if the applied electric field is above a critical value. This value is correlated to the initial geometry of the liquid metal, which increases as the size of the liquid metal decreases. Moreover, the buildup time of a Taylor cone obeys the power law t = k × E{sup −3}, where E is the initial electric field and k is a coefficient related to the material property, indicating a temporal self-similar characteristic. In addition, the influence of temperature has little impact on the deformation but has great impact on electron emission. Finally, the possible reason to initiate a delayed breakdown is associated with the deformation. The breakdown does not occur immediately when the voltage is just applied upon the gap but is postponed to several milliseconds later when the tip is formed on the liquid metal.« less

Kinetics of scrap tyre pyrolysis under vacuum conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez, Gartzen; Aguado, Roberto; Olazar, Martin

2009-10-15

Scrap tyre pyrolysis under vacuum is attractive because it allows easier product condensation and control of composition (gas, liquid and solid). With the aim of determining the effect of vacuum on the pyrolysis kinetics, a study has been carried out in thermobalance. Two data analysis methods have been used in the kinetic study: (i) the treatment of experimental data of weight loss and (ii) the deconvolution of DTG (differential thermogravimetry) curve. The former allows for distinguishing the pyrolysis of the three main components (volatile components, natural rubber and styrene-butadiene rubber) according to three successive steps. The latter method identifies themore » kinetics for the pyrolysis of individual components by means of DTG curve deconvolution. The effect of vacuum in the process is significant. The values of activation energy for the pyrolysis of individual components of easier devolatilization (volatiles and NR) are lower for pyrolysis under vacuum with a reduction of 12 K in the reaction starting temperature. The kinetic constant at 503 K for devolatilization of volatile additives at 0.25 atm is 1.7 times higher than that at 1 atm, and that corresponding to styrene-butadiene rubber at 723 K is 2.8 times higher. Vacuum enhances the volatilization and internal diffusion of products in the pyrolysis process, which contributes to attenuating the secondary reactions of the repolymerization and carbonization of these products on the surface of the char (carbon black). The higher quality of carbon black is interesting for process viability. The large-scale implementation of this process in continuous mode requires a comparison to be made between the economic advantages of using a vacuum and the energy costs, which will be lower when the technologies used for pyrolysis require a lower ratio between reactor volume and scrap tyre flow rate.« less

Kinetics of scrap tyre pyrolysis under vacuum conditions.

PubMed

Lopez, Gartzen; Aguado, Roberto; Olazar, Martín; Arabiourrutia, Miriam; Bilbao, Javier

2009-10-01

Scrap tyre pyrolysis under vacuum is attractive because it allows easier product condensation and control of composition (gas, liquid and solid). With the aim of determining the effect of vacuum on the pyrolysis kinetics, a study has been carried out in thermobalance. Two data analysis methods have been used in the kinetic study: (i) the treatment of experimental data of weight loss and (ii) the deconvolution of DTG (differential thermogravimetry) curve. The former allows for distinguishing the pyrolysis of the three main components (volatile components, natural rubber and styrene-butadiene rubber) according to three successive steps. The latter method identifies the kinetics for the pyrolysis of individual components by means of DTG curve deconvolution. The effect of vacuum in the process is significant. The values of activation energy for the pyrolysis of individual components of easier devolatilization (volatiles and NR) are lower for pyrolysis under vacuum with a reduction of 12K in the reaction starting temperature. The kinetic constant at 503K for devolatilization of volatile additives at 0.25atm is 1.7 times higher than that at 1atm, and that corresponding to styrene-butadiene rubber at 723K is 2.8 times higher. Vacuum enhances the volatilization and internal diffusion of products in the pyrolysis process, which contributes to attenuating the secondary reactions of the repolymerization and carbonization of these products on the surface of the char (carbon black). The higher quality of carbon black is interesting for process viability. The large-scale implementation of this process in continuous mode requires a comparison to be made between the economic advantages of using a vacuum and the energy costs, which will be lower when the technologies used for pyrolysis require a lower ratio between reactor volume and scrap tyre flow rate.

Solid and Liquid Waste Drying Bag

NASA Technical Reports Server (NTRS)

Litwiller, Eric (Inventor); Hogan, John A. (Inventor); Fisher, John W. (Inventor)

2009-01-01

Method and system for processing waste from human activities, including solids, liquids and vapors. A fluid-impermeable bag, lined with a liquid-impermeable but vapor-permeable membrane, defining an inner bag, is provided. A vacuum force is provided to extract vapors so that the waste is moved toward a selected region in the inner bag, extracted vapors, including the waste vapors and vaporized portions of the waste liquids are transported across the membrane, and most or all of the solids remain within the liner. Extracted vapors are filtered, and sanitized components thereof are isolated and optionally stored. The solids remaining within the liner are optionally dried and isolated for ultimate disposal.

In Situ Characterization of Boehmite Particles in Water Using Liquid SEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Juan; Arey, Bruce W.; Yang, Li

In situ imaging and elemental analysis of boehmite (AlOOH) particles in water is realized using the System for Analysis at the Liquid Vacuum Interface (SALVI) and Scanning Electron Microscopy (SEM). This paper describes the method and key steps in integrating the vacuum compatible SAVLI to SEM and obtaining secondary electron (SE) images of particles in liquid in high vacuum. Energy dispersive x-ray spectroscopy (EDX) is used to obtain elemental analysis of particles in liquid. A synthesized AlOOH particle is used as a model in the liquid SEM illustration. Our results demonstrate that particles can be imaged in the SE modemore » with good resolution. The AlOOH EDX spectrum shows significant signal from the Al compared with deionized water and the empty channel control. In situ liquid SEM is a powerful technique to study particles in liquid with many exciting applications. This procedure aims to provide technical details in how to conduct liquid SEM imaging and EDX analysis using SALVI and reduce potential pitfalls using this approach for other researchers.« less

Modelling of crater formation on anode surface by high-current vacuum arcs

NASA Astrophysics Data System (ADS)

Tian, Yunbo; Wang, Zhenxing; Jiang, Yanjun; Ma, Hui; Liu, Zhiyuan; Geng, Yingsan; Wang, Jianhua; Nordlund, Kai; Djurabekova, Flyura

2016-11-01

Anode melting and crater formation significantly affect interruption of high-current vacuum arcs. The primary objective of this paper is to theoretically investigate the mechanism of anode surface crater formation, caused by the combined effect of surface heating during the vacuum arc and pressure exerted on the molten surface by ions and electrons from the arc plasma. A model of fluid flow and heat transfer in the arc anode is developed and combined with a magnetohydrodynamics model of the vacuum arc plasma. Crater formation is observed in simulation for a peak arcing current higher than 15 kA on 40 mm diam. Cu electrodes spaced 10 mm apart. The flow of liquid metal starts after 4 or 5 ms of arcing, and the maximum velocities are 0.95 m/s and 1.39 m/s for 20 kA and 25 kA arcs, respectively. This flow redistributes thermal energy, and the maximum temperature of the anode surface does not remain in the center. Moreover, the condition for the liquid droplet formation on the anode surfaces is developed. The solidification process after current zero is also analyzed. The solidification time has been found to be more than 3 ms after 25 kA arcing. The long solidification time and sharp features on crater rims induce Taylor cone formation.

Pneumatic conveyance apparatus and process

DOEpatents

Heckendorn, Frank M.; Matzolf, Athneal D.; Hera, Kevin R.

2010-05-04

A pneumatic nozzle capable of removing dry solid debris, liquids, and mixtures of solid and liquid waste is provided. The pneumatic nozzle uses a pressurized gas stream to push materials through the nozzle. The force of a pressurized gas stream provides a partial vacuum to allow material to be introduced into an opening of a nozzle via a slight suction force. Thereafter, individual particles and materials introduced into the pneumatic nozzle are pushed by a stream of pressurized gas through the nozzle.

Vacuum plasma coatings for turbine blades

NASA Technical Reports Server (NTRS)

Holmes, R. R.

1985-01-01

Turbine blades, vacuum plasma spray coated with NiCrAlY, CoCrAlY or NiCrAlY/Cr2O3, were evaluated and rated superior to standard space shuttle main engine (SSME) coated blades. Ratings were based primarily on 25 thermal cycles in the MSFC Burner Rig Tester, cycling between 1700 F (gaseous H2) and -423 F (liquid H2). These tests showed no spalling on blades with improved vacuum plasma coatings, while standard blades spalled. Thermal barrier coatings of ZrO2, while superior to standard coatings, lacked the overall performance desired. Fatigue and tensile specimens, machined from MAR-M-246(Hf) test bars identical to the blades were vacuum plasma spray coated, diffusion bond treated, and tested to qualify the vacuum plasma spray process for flight hardware testing and application. While NiCrAlY/Cr2O3 offers significant improvement over standard coatings in durability and thermal protection, studies continue with an objective to develop coatings offering even greater improvements.

In Situ Characterization of Boehmite Particles in Water Using Liquid SEM.

PubMed

Yao, Juan; Arey, Bruce W; Yang, Li; Zhang, Fei; Komorek, Rachel; Chun, Jaehun; Yu, Xiao-Ying

2017-09-27

In situ imaging and elemental analysis of boehmite (AlOOH) particles in water is realized using the System for Analysis at the Liquid Vacuum Interface (SALVI) and Scanning Electron Microscopy (SEM). This paper describes the method and key steps in integrating the vacuum compatible SAVLI to SEM and obtaining secondary electron (SE) images of particles in liquid in high vacuum. Energy dispersive x-ray spectroscopy (EDX) is used to obtain elemental analysis of particles in liquid and control samples including deionized (DI) water only and an empty channel as well. Synthesized boehmite (AlOOH) particles suspended in liquid are used as a model in the liquid SEM illustration. The results demonstrate that the particles can be imaged in the SE mode with good resolution (i.e., 400 nm). The AlOOH EDX spectrum shows significant signal from the aluminum (Al) when compared with the DI water and the empty channel control. In situ liquid SEM is a powerful technique to study particles in liquid with many exciting applications. This procedure aims to provide technical know-how in order to conduct liquid SEM imaging and EDX analysis using SALVI and to reduce potential pitfalls when using this approach.

Improving the Molecular Ion Signal Intensity for In Situ Liquid SIMS Analysis.

PubMed

Zhou, Yufan; Yao, Juan; Ding, Yuanzhao; Yu, Jiachao; Hua, Xin; Evans, James E; Yu, Xiaofei; Lao, David B; Heldebrant, David J; Nune, Satish K; Cao, Bin; Bowden, Mark E; Yu, Xiao-Ying; Wang, Xue-Lin; Zhu, Zihua

2016-12-01

In situ liquid secondary ion mass spectrometry (SIMS) enabled by system for analysis at the liquid vacuum interface (SALVI) has proven to be a promising new tool to provide molecular information at solid-liquid and liquid-vacuum interfaces. However, the initial data showed that useful signals in positive ion spectra are too weak to be meaningful in most cases. In addition, it is difficult to obtain strong negative molecular ion signals when m/z>200. These two drawbacks have been the biggest obstacle towards practical use of this new analytical approach. In this study, we report that strong and reliable positive and negative molecular signals are achievable after optimizing the SIMS experimental conditions. Four model systems, including a 1,8-diazabicycloundec-7-ene (DBU)-base switchable ionic liquid, a live Shewanella oneidensis biofilm, a hydrated mammalian epithelia cell, and an electrolyte popularly used in Li ion batteries were studied. A signal enhancement of about two orders of magnitude was obtained in comparison with non-optimized conditions. Therefore, molecular ion signal intensity has become very acceptable for use of in situ liquid SIMS to study solid-liquid and liquid-vacuum interfaces. Graphical Abstract ᅟ.

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2011-10-01 2011-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2014-10-01 2014-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2012-10-01 2012-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2013-10-01 2013-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

Diesel production from lignocellulosic feed: the bioCRACK process

PubMed Central

Ritzberger, J.; Schwaiger, N.; Pucher, P.; Siebenhofer, M.

2017-01-01

The bioCRACK process is a promising technology for the production of second generation biofuels. During this process, biomass is pyrolized in vacuum gas oil and converted into gaseous, liquid and solid products. In cooperation with the Graz University of Technology, the liquid phase pyrolysis process was investigated by BDI – BioEnergy International AG at an industrial pilot plant, fully integrated in the OMV refinery in Vienna/Schwechat. The influence of various biogenous feedstocks and the influence of the temperature on the product distribution in the temperature range of 350°C to 390°C was studied. It was shown that the temperature has a major impact on the product formation. With rising temperature, the fraction of liquid products, namely liquid CHO-products, reaction water and hydrocarbons, increases and the fraction of biochar decreases. At 390°C, 39.8 wt% of biogenous carbon was transferred into a crude hydrocarbon fractions. The type of lignocellulosic feedstock has a minor impact on the process. The biomass liquefaction concept of the bioCRACK process was in pilot scale compatible with oil refinery processes. PMID:29291098

Ionic Liquids with Symmetric Diether Tails: Bulk and Vacuum-Liquid Interfacial Structures.

PubMed

Hettige, Jeevapani J; Amith, Weththasinghage D; Castner, Edward W; Margulis, Claudio J

2017-01-12

The behavior in the bulk and at interfaces of biphilic ionic liquids in which either the cation or anion possesses moderately long alkyl tails is to a significant degree well understood. Less clear is what happens when both the cation and anion possess tails that are not apolar, such as in the case of ether functionalities. The current article discusses the structural characteristics of C2OC2OC2-mim + /C2OC2OC2-OSO 3 - in the bulk and at the vacuum interface. We find that the vacuum interface affects only the nanometer length scale. This is in contrast to what we have recently found in ( J. Phys. Chem. Lett. , 2016 , 7 ( 19 ), 3785 - -3790 ) for isoelectronic C[8]-mim + /C[8]-OSO 3 - , where the interface effect is long ranged. Interestingly, ions with the diether tail functionality still favor the tail-outward orientation at the vacuum interface and the bulk phase preserves the alternation between charged networks and tails that is commonly observed for biphilic ionic liquids. However, such alternation is less well-defined and results in a significantly diminished first sharp diffraction peak in the bulk liquid structure function.

Nitrogen gas propagation in a liquid helium cooled vacuum tube following a sudden vacuum loss

NASA Astrophysics Data System (ADS)

Dhuley, R. C.; Van Sciver, S. W.

2017-02-01

We present experimental measurements and analysis of propagation of the nitrogen gas that was vented to a high vacuum tube immersed in liquid helium (LHe). The scenario resembles accidental venting of atmospheric air to a SRF beam-line and was investigated to understand how the in-flowing air would propagate in such geometry. The gas front propagation speed in the tube was measured using pressure probes and thermometers installed at regular intervals over the tube length. The experimental data show the front speed to decrease along the vacuum tube. The empirical and analytical models developed to characterize the front deceleration are summarized.

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

Reconfigurable liquid metal circuits by Laplace pressure shaping

NASA Astrophysics Data System (ADS)

Cumby, Brad L.; Hayes, Gerard J.; Dickey, Michael D.; Justice, Ryan S.; Tabor, Christopher E.; Heikenfeld, Jason C.

2012-10-01

We report reconfigurable circuits formed by liquid metal shaping with <10 pounds per square inch (psi) Laplace and vacuum pressures. Laplace pressure drives liquid metals into microreplicated trenches, and upon release of vacuum, the liquid metal dewets into droplets that are compacted to 10-100× less area than when in the channel. Experimental validation includes measurements of actuation speeds exceeding 30 cm/s, simple erasable resistive networks, and switchable 4.5 GHz antennas. Such capability may be of value for next generation of simple electronic switches, tunable antennas, adaptive reflectors, and switchable metamaterials.

Advanced performance of small diaphragm vacuum pumps through the use of mechatronics

NASA Astrophysics Data System (ADS)

Lachenmann, R.; Dirscherl, J.

Oil-free diaphragm vacuum pumps have proven to be the best way in vacuum generation for the chemical laboratory and they also find increasing use as backing pumps for modern wide-range turbo molecular pumps. The majority of vacuum pumps in practical use pump only a rather small percentage of their lifetime at full gas load. A pump backing a turbo molecular pump does not have to pump a significant gas load when the high-vacuum pump is running at ultimate vacuum pressure. Also, for a vacuum distillation the vacuum pump has to operate at full speed only at the beginning to lower the pressure inside the system to a vacuum level where evaporation starts. In a rather leak-tight system the distillation process continues by evaporating from the hot liquid and condensing at the cold condenser without the need of a mechanical vacuum pump. Rotational speed controlled diaphragm pumps are now available through progress in mechatronics and offer high pumping speed capability for fast pump-down cycles and precise pressure control for distillations. At low gas load the rotational speed can be reduced, improving maintenance intervals, power consumption, noise, vibration and - surprisingly - also ultimate pressure. The different behaviour in pumping speed and ultimate pressure of rotational speed controlled diaphragm pumps in comparison to constant-speed pumps is related to the mechanical properties of the valves and gas dynamics .

Catalytic cracking of a Wilmington vacuum oil gas and selected hydrotreated products: Topical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wells, J.W.; Zagula, E.J.

1987-05-01

The catalytic cracking of a Wilmington vacuum gas oil and the products from mild hydrotreating and severe hydrotreating of this gas oil was evaluated over a low metal equilibrium catalyst in a microconfined bed unit (MCBU). Two levels of catalytic cracking severity were evaluated for these three samples. The performance and product analysis showed that hydrotreating improves the quality of catalytic cracker feedstock and the resultant products. The results also indicated that a level of hydrotreating exists above which the quality of the liquid products and the yields of coke and heavy oil are not affected significantly by the severitymore » of the catalytic cracking process. As expected, the sulfur and nitrogen content of the liquid products (gasolines, light cycle oil, and heavy cycle oil) were found to decrease as the severity of the feed hydrotreating increased. The distribution of sulfur and nitrogen in the liquid products was found to be independent of cracking conditions or product yields for a given level of hydrogenation. Analysis of the gas products shows that the degree of hydrogen transfer increases with the severity of hydrogenation. As cracking severity increases, the apparent degree of hydrogen transfer decreases, and the concentration of olefinic compounds increases relative to the saturated compounds. In the future, these results will be compared to similar results from a Mayan vacuum gas oil. 10 refs., 17 figs., 10 tabs.« less

Coal liquefaction process with increased naphtha yields

DOEpatents

Ryan, Daniel F.

1986-01-01

An improved process for liquefying solid carbonaceous materials wherein the solid carbonaceous material is slurried with a suitable solvent and then subjected to liquefaction at elevated temperature and pressure to produce a normally gaseous product, a normally liquid product and a normally solid product. The normally liquid product is further separated into a naphtha boiling range product, a solvent boiling range product and a vacuum gas-oil boiling range product. At least a portion of the solvent boiling-range product and the vacuum gas-oil boiling range product are then combined and passed to a hydrotreater where the mixture is hydrotreated at relatively severe hydrotreating conditions and the liquid product from the hydrotreater then passed to a catalytic cracker. In the catalytic cracker, the hydrotreater effluent is converted partially to a naphtha boiling range product and to a solvent boiling range product. The naphtha boiling range product is added to the naphtha boiling range product from coal liquefaction to thereby significantly increase the production of naphtha boiling range materials. At least a portion of the solvent boiling range product, on the other hand, is separately hydrogenated and used as solvent for the liquefaction. Use of this material as at least a portion of the solvent significantly reduces the amount of saturated materials in said solvent.

Liquid eutectic GaIn as an alternative electrode for PTB7:PCBM organic solar cells

NASA Astrophysics Data System (ADS)

Thanh Hau Pham, Viet; Kieu Trinh, Thanh; Tam Nguyen Truong, Nguyen; Park, Chinho

2017-04-01

Conventional vacuum deposition process of aluminum (Al) is costly, time-consuming and difficult to apply to the large-scale production of organic photovoltaic devices (OPV). This paper reports a vacuum-free fabrication process of poly[[4,8-bis(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b‧]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thienophenediyl]:[6,6]-phenyl C71 butyric acid methyl ester (PTB7:PCBM) bulk heterojunction organic solar cell with liquid eutectic gallium-indium (EGaIn) electrode as an alternative to the common Al electrode. The insertion of a thin poly(ethylene oxide) (PEO) layer after depositing organic photoactive layer could help prevent the diffusion of liquid EGaIn into the active layer and allow the deposition of the EGaIn electrode. The PEO interfacial layer was formed by spin-coating from a mixed solvent of alcohol and water. Among different alcohol+water (methanol, ethanol, ethylene glycol, n-propanol, isopropanol, and isobutanol) mixed solvent tested, the n-propanol+water mixed solvent showed the greatest enhancement to the performance of OPVs. The improved device performance was attributed to the reactivity of mixed solvent n-propanol+water toward the surface of PTB7:PCBM active layer, which could help optimize surface morphology.

Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy.

PubMed

Hermannsdörfer, Justus; de Jonge, Niels

2017-02-05

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline.

Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy

PubMed Central

Hermannsdörfer, Justus; de Jonge, Niels

2017-01-01

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline. PMID:28190028

Comparison of intraocular pressure during the application of a liquid patient interface (FEMTO LDV Z8) for femtosecond laser-assisted cataract surgery using two different vacuum levels.

PubMed

Ebner, Martina; Mariacher, Siegfried; Januschowski, Kai; Boden, Katrin; Seuthe, Anna-Maria; Szurman, Peter; Boden, Karl Thomas

2017-08-01

To evaluate intraocular pressure (IOP) using the application of a novel liquid patient interface for femtosecond laser-assisted cataract surgery with the FEMTO LDV Z8. IOP was evaluated in enucleated porcine eyes prior, during and after the application of the Femto LDV Z8 liquid patient interface (Ziemer Ophthalmic Systems, Switzerland) using intracameral cannulation (n=20), intravitreal cannulation (n=20), rebound tonometry (n=20) and indentation tonometry (n=20). Pressure was assessed prior vacuum, during vacuum (30 s, 1 min, 2 min, 3 min) and after releasing the vacuum (1 min and 2 min). Two groups with different predefined vacuum levels (350 mbar, 420 mbar) were investigated. Mean intracameral pressure (±SD) increased during vacuum application from 20 mm Hg to 52.00 mm Hg (±6.35mm Hg; p=0.005) and 45.18 mmHg (±4.34 mm Hg; p=0.005) for the 420 mbar and the 350 mbar vacuum levels, respectively. Mean intravitreal pressure increased from 20 mm Hg to 25.60 mm Hg (±9.85 mm Hg; p=0.058) and 28.10 mm Hg (±2.54 mm Hg; p=0.059) for the 420 mbar and the 350 mbar vacuum levels, respectively. Pressure values from indentation and rebound tonometry were in between intracameral and intravitreal values. Mean intracameral IOP was 18.1% higher (p=0.019) in the 420 mbar group compared with the 350 mbar group. During vacuum application of the liquid patient interface of the Femto LDV Z8 for femtosecond laser-assisted cataract surgery, IOP values were higher in the anterior chamber compared with the intravitreal pressure measurements. The higher predefined vacuum level (350 mbar vs 420 mbar) resulted in significant higher intracameral IOP. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Fast pyrolysis oil from pinewood chips co-processing with vacuum gas oil in an FCC unit for second generation fuel production

DOE PAGES

Pinho, Andrea de Rezende; de Almeida, Marlon B. B.; Mendes, Fabio Leal; ...

2016-10-15

Raw bio-oil produced from fast pyrolysis of pine woodchips was co-processed with standard Brazilian vacuum gasoil (VGO) and tested in a 200 kg•h -1 fluid catalytic cracking (FCC) demonstration-scale unit using a commercial FCC equilibrium catalyst. Two different bio-oil/VGO weight ratios were used: 5/95 and 10/90. Co-processing of raw bio-oil in FCC was shown to be technically feasible. Bio-oil could be directly co-processed with a regular gasoil FCC feed up to 10 wt%. The bio-oil and the conventional gasoil were cracked into valuable liquid products such as gasoline and diesel range products. Most of the oxygen present in the bio-oilmore » was eliminated as water and carbon monoxide as these yields were always higher than that of carbon dioxide. Product quality analysis shows that trace oxygenates, primarily alkyl phenols, in FCC gasoline and diesel products are present with or without co-processing oxygenated intermediates. The oxygenate concentrations increase with co-processing, but have not resulted in increased concerns with quality of fuel properties. The presence of renewable carbon was confirmed in gasoline and diesel cuts through 14C isotopic analysis, showing that renewable carbon is not only being converted into coke, CO, and CO 2, but also into valuable refining liquid products. Thus, gasoline and diesel could be produced from lignocellulosic raw materials through a conventional refining scheme, which uses the catalytic cracking process. As a result, the bio-oil renewable carbon conversion into liquid products (carbon efficiency) was approximately 30%, well above the efficiency found in literature for FCC bio-oil upgrading.« less

Fast pyrolysis oil from pinewood chips co-processing with vacuum gas oil in an FCC unit for second generation fuel production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pinho, Andrea de Rezende; de Almeida, Marlon B. B.; Mendes, Fabio Leal

Raw bio-oil produced from fast pyrolysis of pine woodchips was co-processed with standard Brazilian vacuum gasoil (VGO) and tested in a 200 kg•h -1 fluid catalytic cracking (FCC) demonstration-scale unit using a commercial FCC equilibrium catalyst. Two different bio-oil/VGO weight ratios were used: 5/95 and 10/90. Co-processing of raw bio-oil in FCC was shown to be technically feasible. Bio-oil could be directly co-processed with a regular gasoil FCC feed up to 10 wt%. The bio-oil and the conventional gasoil were cracked into valuable liquid products such as gasoline and diesel range products. Most of the oxygen present in the bio-oilmore » was eliminated as water and carbon monoxide as these yields were always higher than that of carbon dioxide. Product quality analysis shows that trace oxygenates, primarily alkyl phenols, in FCC gasoline and diesel products are present with or without co-processing oxygenated intermediates. The oxygenate concentrations increase with co-processing, but have not resulted in increased concerns with quality of fuel properties. The presence of renewable carbon was confirmed in gasoline and diesel cuts through 14C isotopic analysis, showing that renewable carbon is not only being converted into coke, CO, and CO 2, but also into valuable refining liquid products. Thus, gasoline and diesel could be produced from lignocellulosic raw materials through a conventional refining scheme, which uses the catalytic cracking process. As a result, the bio-oil renewable carbon conversion into liquid products (carbon efficiency) was approximately 30%, well above the efficiency found in literature for FCC bio-oil upgrading.« less

Using vacuum pyrolysis and mechanical processing for recycling waste printed circuit boards.

PubMed

Long, Laishou; Sun, Shuiyu; Zhong, Sheng; Dai, Wencan; Liu, Jingyong; Song, Weifeng

2010-05-15

The constant growth in generation of waste printed circuit boards (WPCB) poses a huge disposal problem because they consist of a heterogeneous mixture of organic and metallic chemicals as well as glass fiber. Also the presence of heavy metals, such as Pb and Cd turns this scrap into hazardous waste. Therefore, recycling of WPCB is an important subject not only from the recovery of valuable materials but also from the treatment of waste. The aim of this study was to present a recycling process without negative impact to the environment as an alternative for recycling WPCB. In this work, a process technology containing vacuum pyrolysis and mechanical processing was employed to recycle WPCB. At the first stage of this work, the WPCB was pyrolyzed under vacuum in a self-made batch pilot-scale fixed bed reactor to recycle organic resins contained in the WPCB. By vacuum pyrolysis the organic matter was decomposed to gases and liquids which could be used as fuels or chemical material resources, however, the inorganic WPCB matter was left unaltered as solid residues. At the second stage, the residues obtained at the first stage were investigated to separate and recover the copper through mechanical processing such as crushing, screening, and gravity separation. The copper grade of 99.50% with recovery of 99.86% based on the whole WPCB was obtained. And the glass fiber could be obtained by calcinations in a muffle furnace at 600 degrees C for 10 min. This study had demonstrated the feasibility of vacuum pyrolysis and mechanical processing for recycling WPCB. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Novel Approach for in Situ Recovery of Lithium Carbonate from Spent Lithium Ion Batteries Using Vacuum Metallurgy.

PubMed

Xiao, Jiefeng; Li, Jia; Xu, Zhenming

2017-10-17

Lithium is a rare metal because of geographical scarcity and technical barrier. Recycling lithium resource from spent lithium ion batteries (LIBs) is significant for lithium deficiency and environmental protection. A novel approach for recycling lithium element as Li 2 CO 3 from spent LIBs is proposed. First, the electrode materials preobtained by mechanical separation are pyrolyzed under enclosed vacuum condition. During this process the Li is released as Li 2 CO 3 from the crystal structure of lithium transition metal oxides due to the collapse of the oxygen framework. An optimal Li recovery rate of 81.90% is achieved at 973 K for 30 min with a solid-to-liquid ratio of 25 g L -1 , and the purity rate of Li 2 CO 3 is 99.7%. The collapsed mechanism is then presented to explain the release of lithium element during the vacuum pyrolysis. Three types of spent LIBs including LiMn 2 O 4 , LiCoO 2 , and LiCo x Mn y Ni z O 2 are processed to prove the validity of in situ recycling Li 2 CO 3 from spent LIBs under enclosed vacuum condition. Finally, an economic assessment is taken to prove that this recycling process is positive.

Improving the Molecular Ion Signal Intensity for In Situ Liquid SIMS Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yufan; Yao, Juan; Ding, Yuanzhao

In situ liquid secondary ion mass spectrometry (SIMS) enabled by system for analysis at the liquid vacuum interface (SALVI) has proven to be a promising new tool to provide molecular information at solid–liquid and liquid–vacuum interfaces. However, the initial data showed that useful signals in positive ion spectra are too weak to be meaningful in most cases. In addition, it is difficult to obtain strong negative molecular ion signals when m/z>200. These two drawbacks have been the biggest obstacle towards practical use of this new analytical approach. In this study, we report that strong and reliable positive and negative molecularmore » signals are achievable after optimizing the SIMS experimental conditions. Four model systems, including a 1,8-diazabicycloundec-7-ene (DBU)-base switchable ionic liquid, a live Shewanella oneidensis biofilm, a hydrated mammalian epithelia cell, and an electrolyte popularly used in Li ion batteries were studied. A signal enhancement of about two orders of magnitude was obtained in comparison with non-optimized conditions. Therefore, molecular ion signal intensity has become very acceptable to use for in situ liquid SIMS to study solid–liquid and liquid–vacuum interfaces.« less

A Rolling Element Tribometer for the Study of Liquid Lubricants in Vacuum

NASA Technical Reports Server (NTRS)

Pepper, Stephen V.; Ebihara, Ben T.; Kingsbury, Edward

1996-01-01

A tribometer for the evaluation of liquid lubricants in vacuum is described. This tribometer is essentially a thrust bearing with three balls and flat races having contact stresses and ball motions similar to those in an angular contact ball bearing operating in the boundary lubrication regime. The friction coefficient, lubrication lifetime, and species evolved from the liquid lubricant by tribodegradation can be determined. A complete analysis of the contact stresses and energy dissipation together with experimental evidence supporting the analysis are presented.

An effective vacuum assisted extraction method for the optimization of labdane diterpenoids from Andrographis paniculata by response surface methodology.

PubMed

Wang, Ya-Qi; Wu, Zhen-Feng; Ke, Gang; Yang, Ming

2014-12-31

An effective vacuum assisted extraction (VAE) technique was proposed for the first time and applied to extract bioactive components from Andrographis paniculata. The process was carefully optimized by response surface methodology (RSM). Under the optimized experimental conditions, the best results were obtained using a boiling temperature of 65 °C, 50% ethanol concentration, 16 min of extraction time, one extraction cycles and a 12:1 liquid-solid ratio. Compared with conventional ultrasonic assisted extraction and heat reflux extraction, the VAE technique gave shorter extraction times and remarkable higher extraction efficiency, which indicated that a certain degree of vacuum gave the solvent a better penetration of the solvent into the pores and between the matrix particles, and enhanced the process of mass transfer. The present results demonstrated that VAE is an efficient, simple and fast method for extracting bioactive components from A. paniculata, which shows great potential for becoming an alternative technique for industrial scale-up applications.

Safety studies on vacuum insulated liquid helium cryostats

NASA Astrophysics Data System (ADS)

Weber, C.; Henriques, A.; Zoller, C.; Grohmann, S.

2017-12-01

The loss of insulating vacuum is often considered as a reasonable foreseeable accident for the dimensioning of cryogenic safety relief devices (SRD). The cryogenic safety test facility PICARD was designed at KIT to investigate such events. In the course of first experiments, discharge instabilities of the spring loaded safety relief valve (SRV) occurred, the so-called chattering and pumping effects. These instabilities reduce the relief flow capacity, which leads to impermissible over-pressures in the system. The analysis of the process dynamics showed first indications for a smaller heat flux than the commonly assumed 4W/cm2. This results in an oversized discharge area for the reduced relief flow rate, which corresponds to the lower heat flux. This paper presents further experimental investigations on the venting of the insulating vacuum with atmospheric air under variation of the set pressure (p set) of the SRV. Based on dynamic process analysis, the results are discussed with focus on effective heat fluxes and operating characteristics of the spring-loaded SRV.

46 CFR 39.2011 - Vapor overpressure and vacuum protection-TB/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... freely and does not remain in the open position. (c) A liquid filled pressure-vacuum breaker may be used... 46 Shipping 1 2014-10-01 2014-10-01 false Vapor overpressure and vacuum protection-TB/ALL. 39.2011... Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank...

46 CFR 39.2011 - Vapor overpressure and vacuum protection-TB/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... freely and does not remain in the open position. (c) A liquid filled pressure-vacuum breaker may be used... 46 Shipping 1 2013-10-01 2013-10-01 false Vapor overpressure and vacuum protection-TB/ALL. 39.2011... Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank...

Advanced Supported Liquid Membranes for Carbon Dioxide Control in Extravehicular Activity Applications

NASA Technical Reports Server (NTRS)

Gleason, Kevin J. (Inventor); Cowley, Scott W. (Inventor); Wickham, David T. (Inventor)

2015-01-01

There is disclosed a portable life support system with a component for removal of at least one selected gas. In an embodiment, the system includes a supported liquid membrane having a first side and a second side in opposition to one another, the first side configured for disposition toward an astronaut and the second side configured for disposition toward a vacuum atmosphere. The system further includes an ionic liquid disposed between the first side and the second side of the supported liquid membrane, the ionic liquid configured for removal of at least one selected gas from a region housing the astronaut adjacent the first side of the supported liquid membrane to the vacuum atmosphere adjacent the second side of the supported liquid membrane. Other embodiments are also disclosed.

Gas propagation in a liquid helium cooled vacuum tube following a sudden vacuum loss

NASA Astrophysics Data System (ADS)

Dhuley, Ram C.

This dissertation describes the propagation of near atmospheric nitrogen gas that rushes into a liquid helium cooled vacuum tube after the tube suddenly loses vacuum. The loss-of-vacuum scenario resembles accidental venting of atmospheric air to the beam-line of a superconducting radio frequency particle accelerator and is investigated to understand how in the presence of condensation, the in-flowing air will propagate in such geometry. In a series of controlled experiments, room temperature nitrogen gas (a substitute for air) at a variety of mass flow rates was vented to a high vacuum tube immersed in a bath of liquid helium. Pressure probes and thermometers installed on the tube along its length measured respectively the tube pressure and tube wall temperature rise due to gas flooding and condensation. At high mass in-flow rates a gas front propagated down the vacuum tube but with a continuously decreasing speed. Regression analysis of the measured front arrival times indicates that the speed decreases nearly exponentially with the travel length. At low enough mass in-flow rates, no front propagated in the vacuum tube. Instead, the in-flowing gas steadily condensed over a short section of the tube near its entrance and the front appeared to `freeze-out'. An analytical expression is derived for gas front propagation speed in a vacuum tube in the presence of condensation. The analytical model qualitatively explains the front deceleration and flow freeze-out. The model is then simplified and supplemented with condensation heat/mass transfer data to again find the front to decelerate exponentially while going away from the tube entrance. Within the experimental and procedural uncertainty, the exponential decay length-scales obtained from the front arrival time regression and from the simplified model agree.

Research of vacuum polymer film on three-dimension surface (Conference Presentation)

NASA Astrophysics Data System (ADS)

Bau, Yung-Han

2016-09-01

This study focused on UV-curable acrylic hybrid of solute in vacuum-deposited on the surface and make it smooth. On the surface coating of the entire process, including the pre-treatment of organic solutes, vacuum, nozzle pressure, airflow, frequency ratio, the surface of the rotation rate, nozzle angle, UV light irradiation time, waste solute recycling.Organic solutes through a flow meter and precise measured,by high pressure or vibration of a piezoelectric material, spray our organic solute in a certain degree of vacuum,leaving nozzle of tiny micro-mist volatiles in a vacuum to form secondary atomization,deposited our surface,Since no UV light irradiation, the surface is a liquid having fluidity, so the non-planar substrates can have good performance, finally it is irradiated by UV light of sufficient energy solidify to form a solid film.The advantage of this approach is that a smooth surface,Strong adhesion, low-cost equipment, low temperature, a wide range of high deposition rate can be combined with other deposition method,Under vacuum have not waste because excess paint can be recycled.Avoid solute direct contact with human, relative to the environment-friendly.

MStern Blotting-High Throughput Polyvinylidene Fluoride (PVDF) Membrane-Based Proteomic Sample Preparation for 96-Well Plates.

PubMed

Berger, Sebastian T; Ahmed, Saima; Muntel, Jan; Cuevas Polo, Nerea; Bachur, Richard; Kentsis, Alex; Steen, Judith; Steen, Hanno

2015-10-01

We describe a 96-well plate compatible membrane-based proteomic sample processing method, which enables the complete processing of 96 samples (or multiples thereof) within a single workday. This method uses a large-pore hydrophobic PVDF membrane that efficiently adsorbs proteins, resulting in fast liquid transfer through the membrane and significantly reduced sample processing times. Low liquid transfer speeds have prevented the useful 96-well plate implementation of FASP as a widely used membrane-based proteomic sample processing method. We validated our approach on whole-cell lysate and urine and cerebrospinal fluid as clinically relevant body fluids. Without compromising peptide and protein identification, our method uses a vacuum manifold and circumvents the need for digest desalting, making our processing method compatible with standard liquid handling robots. In summary, our new method maintains the strengths of FASP and simultaneously overcomes one of the major limitations of FASP without compromising protein identification and quantification. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

MStern Blotting–High Throughput Polyvinylidene Fluoride (PVDF) Membrane-Based Proteomic Sample Preparation for 96-Well Plates*

PubMed Central

Berger, Sebastian T.; Ahmed, Saima; Muntel, Jan; Cuevas Polo, Nerea; Bachur, Richard; Kentsis, Alex; Steen, Judith; Steen, Hanno

2015-01-01

We describe a 96-well plate compatible membrane-based proteomic sample processing method, which enables the complete processing of 96 samples (or multiples thereof) within a single workday. This method uses a large-pore hydrophobic PVDF membrane that efficiently adsorbs proteins, resulting in fast liquid transfer through the membrane and significantly reduced sample processing times. Low liquid transfer speeds have prevented the useful 96-well plate implementation of FASP as a widely used membrane-based proteomic sample processing method. We validated our approach on whole-cell lysate and urine and cerebrospinal fluid as clinically relevant body fluids. Without compromising peptide and protein identification, our method uses a vacuum manifold and circumvents the need for digest desalting, making our processing method compatible with standard liquid handling robots. In summary, our new method maintains the strengths of FASP and simultaneously overcomes one of the major limitations of FASP without compromising protein identification and quantification. PMID:26223766

Applications of KPFM-Based Approaches for Surface Potential and Electrochemical Measurements in Liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, Liam F.; Weber, Stefan A. L.; Rodriguez, Brian

Kelvin probe force microscopy (KPFM) has been widely used to map nanoscale surface potentials of materials in ambient and ultra-high vacuum environments. However, to study and ultimately understand charge-related processes, e.g., in biological systems or to further improve energy storage devices such as electrochemical batteries, nanoscale surface potential measurements in liquid environments are required. Here, we describe the various implementations of KPFM-based approaches for measuring surface potentials in liquid environments. We provide practical guidelines for surface potential measurements and describe what other information can be obtained. Finally, we discuss potential applications and limitations of existing approaches and present possible solutionsmore » for the successful implementation of liquid KPFM.« less

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 1 2014-10-01 2014-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

Venting and High Vacuum Performance of Low Density Multilayer Insulation

NASA Astrophysics Data System (ADS)

Riesco, M. E.; McLean, C. H.; Mills, G. L.; Buerger, S.; Meyer, M. L.

2010-04-01

The NASA Exploration Program is currently studying the use liquid oxygen, liquid methane and liquid hydrogen for propulsion in future spacecraft for Exploration of the Moon and Mars. This will require the efficient long term, on-orbit storage of these cryogenic propellants. Multilayer Insulation (MLI) will be critical to achieving the required thermal performance since it has much lower heat transfer than any other insulation when used in a vacuum. MLI with a low density (⩽10 layers/cm) has been shown in previous work to be the most mass efficient. The size and mass constraints of these propulsion systems will not allow a structural shell to be used to provide vacuum for the MLI during ground hold and launch. The baseline approach is to purge the MLI during ground hold with an inert gas which is then vented during launch ascent and on-orbit. This paper presents the results on experimental tests and modeling performed by Ball Aerospace on low density, non-perforated MLI used to insulate a cryogenic tank simulating an Exploration cryogenic propellant storage vessel. These include measurements of the rate of venting and of the heat transfer of gas filled insulation, fully evacuated insulation and during the transition in between. Results of transient computer modeling of the MLI venting and heat transfer process are also presented. Previous work by some of the authors performed vent testing using MLI with perforations and slits and a slow pump down rate.

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Pressure and vacuum pulse test... (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and vacuum pulse test. Liquid retention components of the device with manufacturer specified venting...

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Pressure and vacuum pulse test... (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and vacuum pulse test. Liquid retention components of the device with manufacturer specified venting...

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Pressure and vacuum pulse test... (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and vacuum pulse test. Liquid retention components of the device with manufacturer specified venting...

Metabolomics method based on ultra high performance liquid chromatography with time-of-flight mass spectrometry to analyze toxins in fresh and dried toad venom.

PubMed

Ma, Hongyue; Niu, Huixia; Cao, Qin; Zhou, Jing; Gong, Yan; Zhu, Zhenhua; Lv, Xiang; Di, Liuqing; Qian, Dawei; Wu, Qinan; Duan, Jin'ao

2016-12-01

Drying is a critical step to prolong the storage time in natural medicine processing but it changes the chemical characteristics of the product. In this study, research was performed to characterize the metabolomic changes in toad venom induced by vacuum-drying at 60°C and air-drying at room temperature by ultra high performance liquid chromatography coupled with pattern recognition approaches. In total 52 metabolites, down-regulated or up-regulated, were identified as potential chemical markers. Compared with fresh toad venom, vacuum-drying at 60°C succeeded in raising the conjugated-type bufadienolide content significantly, while the content of free-type bufadienolides were slightly reduced. On the other hand, toad venom air-dried at room temperature presented a relatively low amount of bufadienolides compared with fresh venom. For example, the content of several known anti-tumor components (gamabufotalin, bufotalin, cinobufagin, etc.) were significantly reduced. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide bioassay further showed that venom air-dried at room temperature had weaker anti-tumor activity on human hepatocellular carcinoma SMMC-7721 proliferation in vitro than samples vacuum-dried at 60°C. These results showed that the great metabolomic changes of toad venom occurred during the drying process, suggesting that a proper drying procedure is important for sustaining the chemical quality of natural medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid detection circuit

DOEpatents

Regan, Thomas O.

1987-01-01

Herein is a circuit which is capable of detecting the presence of liquids, especially cryogenic liquids, and whose sensor will not overheat in a vacuum. The circuit parameters, however, can be adjusted to work with any liquid over a wide range of temperatures.

NLS propulsion - Government view

NASA Technical Reports Server (NTRS)

Smelser, Jerry W.

1992-01-01

The paper discusses the technology development for the Space Transportation Main Engine (STME). The STME is a liquid oxygen/liquid hydrogen engine with 650,000 pounds of thrust, which may be flown in single-engine or multiple-engine configurations, depending upon the payload and mission requirements. The technological developments completed so far include a vacuum plasma spray process, the liquid interface diffusion bonding, and a thin membrane platelet technology for the combustion chamber fabrication; baseline designs for the hydrogen turbopump and the oxygen pump; and the engine control system. The family of spacecraft for which this engine is being developed includes a 20,000 pound payload to LEO and a 150,000 pound to LEO vehicle.

Effects of Background Pressure on Relativistic Laser-Plasma Interaction Ion Acceleration

NASA Astrophysics Data System (ADS)

Peterson, Andrew; Orban, C.; Feister, S.; Ngirmang, G.; Smith, J. T.; Klim, A.; Frische, K.; Morrison, J.; Chowdhury, E.; Roquemore, W. M.

2016-10-01

Typically, ultra-intense laser-accelerated ion experiments are carried out under high-vacuum conditions and with a repetition rate up to several shots per day. Looking to the future there is a need to perform these experiments with a much larger repetition rate. A continuously flowing liquid target is more suitable than a solid target for this purpose. However liquids vaporize below their vapor pressure, and the experiment cannot be performed under high-vacuum conditions. The effects of this non-negligible high chamber pressure acceleration of charged particles is not yet well understood. We investigate this phenomena using Particle-in-Cell simulations, exploring the effect of the background pressure on the accelerated ion spectrum. Experiments in this regime are being performed at the Air Force Research Laboratory at Wright-Patterson Air Force Base. This research was sponsored by the Quantum and Non-Equilibrium Processes Division of the Air Force Office of Scientific Research, under the management of Dr. Enrique Parra, Program Manager and significant support from the DOD HPCMP Internship Program.

Maximum Expected Wall Heat Flux and Maximum Pressure After Sudden Loss of Vacuum Insulation on the Stratospheric Observatory for Infrared Astronomy (SOFIA) Liquid Helium (LHe) Dewars

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.

2014-01-01

The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared observation experiments. The experiments carry sensors cooled to liquid helium (LHe) temperatures. A question arose regarding the heat input and peak pressure that would result from a sudden loss of the dewar vacuum insulation. Owing to concerns about the adequacy of dewar pressure relief in the event of a sudden loss of the dewar vacuum insulation, the SOFIA Program engaged the NASA Engineering and Safety Center (NESC). This report summarizes and assesses the experiments that have been performed to measure the heat flux into LHe dewars following a sudden vacuum insulation failure, describes the physical limits of heat input to the dewar, and provides an NESC recommendation for the wall heat flux that should be used to assess the sudden loss of vacuum insulation case. This report also assesses the methodology used by the SOFIA Program to predict the maximum pressure that would occur following a loss of vacuum event.

Method for sealing an ultracapacitor, and related articles

DOEpatents

Day, James; Shapiro, Andrew Philip; Jerabek, Elihu Calvin

2000-08-29

An improved process for sealing at least one ultracapacitor which includes a multi-layer structure is disclosed. The process includes the step of applying a substantial vacuum to press together an uppermost layer of the structure and a lowermost layer of the structure and to evacuate ambient gasses, wherein a sealant situated in a peripheral area between the facing surfaces of the layers forms a liquid-impermeable seal for the structure under the vacuum. In some embodiments, a press is used to apply pressure to the peripheral area on which the sealant is disposed. Usually, the ultracapacitor would be situated within an enclosable region of the press, and a collapsible membrane would be fastened over the ultracapacitor to fully enclose the region and transmit the vacuum force to the multi-layer structure. The force applied by the press itself causes the sealant to flow, thereby ensuring a complete seal upon curing of the sealant. This process can be employed to seal one ultracapacitor or a stack of at least two ultracapacitors. Another embodiment of this invention is directed to an apparatus for sealing a multi-layer ultracapacitor, comprising the elements described above.

Experiments on Nucleation in Different Flow Regimes

NASA Technical Reports Server (NTRS)

Bayuzick, R. J.; Hofmeister, W. H.; Morton, C. M.; Robinson, M. B.

1998-01-01

The vast majority of metallic engineering materials are solidified from the liquid phase. Understanding the solidification process is essential to control microstructure, which in turn, determines the properties of materials. The genesis of solidification is nucleation, where the first stable solid forms from the liquid phase. Nucleation kinetics determine the degree of undercooling and phase selection. As such, it is important to understand nucleation phenomena in order to control solidification or glass formation in metals and alloys. Early experiments in nucleation kinetics were accomplished by droplet dispersion methods. Dilitometry was used by Turnbull and others, and more recently differential thermal analysis and differential scanning calorimetry have been used for kinetic studies. These techniques have enjoyed success; however, there are difficulties with these experiments. Since materials are dispersed in a medium, the character of the emulsion/metal interface affects the nucleation behavior. Statistics are derived from the large number of particles observed in a single experiment, but dispersions have a finite size distribution which adds to the uncertainty of the kinetic determinations. Even though temperature can be controlled quite well before the onset of nucleation, the release of the latent heat of fusion during nucleation of particles complicates the assumption of isothermality during these experiments. Containerless processing has enabled another approach to the study of nucleation kinetics. With levitation techniques it is possible to undercool one sample to nucleation repeatedly in a controlled manner, such that the statistics of the nucleation process can be derived from multiple experiments on a single sample. The authors have fully developed the analysis of nucleation experiments on single samples following the suggestions of Skripov. The advantage of these experiments is that the samples are directly observable. The nucleation temperature can be measured by noncontact optical pyrometry, the mass of the sample is known, and post-processing analysis can be conducted on the sample. The disadvantages are that temperature measurement must have exceptionally high precision, and it is not possible to isolate specific heterogeneous sites as in droplet dispersions. Levitation processing of refractory materials in ultra high vacuum provides an avenue to conduct these kinetic studies on single samples. Two experimental methods have been identified where ultra high vacuum experiments are possible; electrostatic levitation in ground-based experiments and electromagnetic processing in low earth orbit on TEMPUS. Such experiments, reported here, were conducted on zirconium. Liquid zirconium is an excellent solvent and has a high solubility for contaminants contained in the bulk material as well as those contaminants found in the vacuum environment. Oxides, nitrides, and carbides do not exist in the melt, and do not form on the surface of molten zirconium, for the materials and vacuum levels used in this study. Ground-based experiments with electrostatic levitation have shown that the statistical nucleation kinetic experiments are viable and yield results which are consistent with classical nucleation theory. The advantage of low earth orbit experiments is the ability to vary the flow conditions in the liquid prior to nucleation. The put-pose of nucleation experiments in TEMPUS was to examine.

On the instability of a liquid sheet moving in vacuum

NASA Astrophysics Data System (ADS)

Sisoev, G. M.; Osiptsov, A. N.; Koroteev, A. A.

2018-03-01

A linear stability analysis of a non-isothermal liquid sheet moving in vacuum is studied taking into account the temperature dependencies of the liquid viscosity, thermal conductivity, and surface tension coefficients. It is found that there are two mechanisms of instability. The short-wave instability is caused by viscosity stratification across the sheet due to nonuniform temperature profiles developed downstream in the cooling sheet. The long-wave thermocapillary instability is caused by the temperature gradient along the sheet surfaces. Computed examples of steady flows and their instabilities demonstrated that the unstable short waves have much larger amplification factors.

Water adsorption on a liquid surface.

PubMed

Lovelock, Kevin R J; Smith, Emily F; Deyko, Alexey; Villar-Garcia, Ignacio J; Licence, Peter; Jones, Robert G

2007-12-14

Monolayer adsorption of water onto an ionic liquid in ultra-high vacuum has been demonstrated, revealing a heat of adsorption which exceeds the heat of absorption into the bulk liquid by approximately 40 kJ mol(-1).

Process for preparing lubricating oil from used waste lubricating oil

DOEpatents

Whisman, Marvin L.; Reynolds, James W.; Goetzinger, John W.; Cotton, Faye O.

1978-01-01

A re-refining process is described by which high-quality finished lubricating oils are prepared from used waste lubricating and crankcase oils. The used oils are stripped of water and low-boiling contaminants by vacuum distillation and then dissolved in a solvent of 1-butanol, 2-propanol and methylethyl ketone, which precipitates a sludge containing most of the solid and liquid contaminants, unspent additives, and oxidation products present in the used oil. After separating the purified oil-solvent mixture from the sludge and recovering the solvent for recycling, the purified oil is preferably fractional vacuum-distilled, forming lubricating oil distillate fractions which are then decolorized and deodorized to prepare blending stocks. The blending stocks are blended to obtain a lubricating oil base of appropriate viscosity before being mixed with an appropriate additive package to form the finished lubricating oil product.

A vacuum four-ball tribometer to evaluate liquid lubricants for space applications

NASA Technical Reports Server (NTRS)

Masuko, Masabumi; Jones, William R., Jr.; Jansen, Ralph; Ebihara, Ben; Pepper, Stephen V.; Helmick, Larry S.

1993-01-01

The design and operation of a vacuum tribometer, based on the four-ball configuration, is described. This tribometer evaluates the tribological characteristics of liquid lubricants for space applications. Operating conditions include: room temperature, loads to approximately 1000N, speeds to approximately 500 rpm, and pressures of approximately 10(exp -6)Pa. Tests can also be run at atmospheric pressure with air or nitrogen. Some typical test results are included.

Electrokinetic electrode system for extraction of soil contaminants from unsaturated soils

DOEpatents

Lindgren, Eric R.; Mattson, Earl D.

1995-01-01

There is presented an electrokinetic electrode assembly for use in extraction of soil contaminants from unsaturated soil in situ. The assembly includes a housing for retaining a liquid comprising an electrolyte solution, pure water, and soil water, the housing being in part of porous material capable of holding a vacuum. An electrode is mounted in the housing. The housing is provided with a vacuum orifice for effecting a vacuum within the housing selectively to control flow of soil water through the housing into the chamber and to control outflow of the liquid from the chamber. The assembly further includes conduit means for removing the liquid from the housing and returning the electrolyte solution to the housing, and a conduit for admitting pure water to the housing. There is further presented an electrode system and method for extraction of soil contaminants, the system and method utilizing at least two electrode assemblies as described above.

Electrokinetic electrode system for extraction of soil contaminants from unsaturated soils

DOEpatents

Lindgren, E.R.; Mattson, E.D.

1995-07-25

An electrokinetic electrode assembly is described for use in extraction of soil contaminants from unsaturated soil in situ. The assembly includes a housing for retaining a liquid comprising an electrolyte solution, pure water, and soil water, the housing being in part of porous material capable of holding a vacuum. An electrode is mounted in the housing. The housing is provided with a vacuum orifice for effecting a vacuum within the housing selectively to control flow of soil water through the housing into the chamber and to control outflow of the liquid from the chamber. The assembly further includes conduit means for removing the liquid from the housing and returning the electrolyte solution to the housing, and a conduit for admitting pure water to the housing. An electrode system and method are also revealed for extraction of soil contaminants. The system and method utilize at least two electrode assemblies as described above. 5 figs.

Insulation Test Cryostat with Lift Mechanism

NASA Technical Reports Server (NTRS)

Dokos, Adam G. (Inventor); Fesmire, James E. (Inventor)

2014-01-01

A multi-purpose, cylindrical thermal insulation test apparatus is used for testing insulation materials and systems of materials using a liquid boil-off calorimeter system for absolute measurement of the effective thermal conductivity (k-value) and heat flux of a specimen material at a fixed environmental condition (cold-side temperature, warm-side temperature, vacuum pressure level, and residual gas composition). The apparatus includes an inner vessel for receiving a liquid with a normal boiling point below ambient temperature, such as liquid nitrogen, enclosed within a vacuum chamber. A cold mass assembly, including the upper and lower guard chambers and a middle test vessel, is suspended from a lid of the vacuum canister. Each of the three chambers is filled and vented through a single feedthrough. All fluid and instrumentation feedthroughs are mounted and suspended from a top domed lid to allow easy removal of the cold mass. A lift mechanism allows manipulation of the cold mass assembly and insulation test article.

Insulation Test Cryostat with Lift Mechanism

NASA Technical Reports Server (NTRS)

Fesmire, James E. (Inventor); Dokos, Adam G. (Inventor)

2016-01-01

A multi-purpose, cylindrical thermal insulation test apparatus is used for testing insulation materials and systems of materials using a liquid boil-off calorimeter system for absolute measurement of the effective thermal conductivity (k-value) and heat flux of a specimen material at a fixed environmental condition (cold-side temperature, warm-side temperature, vacuum pressure level, and residual gas composition). An inner vessel receives liquid with a normal boiling point below ambient temperature, such as liquid nitrogen, enclosed within a vacuum chamber. A cold mass assembly, including upper and lower guard chambers and middle test vessel, is suspended from a lid of the vacuum canister. Each of the three chambers is filled and vented through a single feedthrough. All fluid and instrumentation feedthroughs are mounted and suspended from a top domed lid allowing easy removal of the cold mass. A lift mechanism allows manipulation of the cold mass assembly and insulation test article.

Vapor-Gas Bubble Evolution and Growth in Extremely Viscous Fluids Under Vacuum

NASA Technical Reports Server (NTRS)

Kizito, John; Balasubramaniam, R.; Nahra, Henry; Agui, Juan; Truong, Duc

2008-01-01

Formation of vapor and gas bubbles and voids is normal and expected in flow processes involving extremely viscous fluids in normal gravity. Practical examples of extremely viscous fluids are epoxy-like filler materials before the epoxy fluids cure to their permanent form to create a mechanical bond between two substrates. When these fluids flow with a free liquid interface exposed to vacuum, rapid bubble expansion process may ensue. Bubble expansion might compromise the mechanical bond strength. The potential sources for the origin of the gases might be incomplete out-gassing process prior to filler application; regasification due to seal leakage in the filler applicator; and/or volatiles evolved from cure reaction products formed in the hardening process. We embarked on a study that involved conducting laboratory experiments with imaging diagnostics in order to deduce the seriousness of bubbling caused by entrained air and volatile fluids under space vacuum and low gravity environment. We used clear fluids with the similar physical properties as the epoxy-like filler material to mimic the dynamics of bubbles. Another aspect of the present study was to determine the likelihood of bubbling resulting from dissolved gases nucleating from solution. These experimental studies of the bubble expansion are compared with predictions using a modified Rayleigh- Plesset equation, which models the bubble expansion.

Optimizing Polymer Infusion Process for Thin Ply Textile Composites with Novel Matrix System

PubMed Central

Bhudolia, Somen K.; Perrotey, Pavel; Joshi, Sunil C.

2017-01-01

For mass production of structural composites, use of different textile patterns, custom preforming, room temperature cure high performance polymers and simplistic manufacturing approaches are desired. Woven fabrics are widely used for infusion processes owing to their high permeability but their localised mechanical performance is affected due to inherent associated crimps. The current investigation deals with manufacturing low-weight textile carbon non-crimp fabrics (NCFs) composites with a room temperature cure epoxy and a novel liquid Methyl methacrylate (MMA) thermoplastic matrix, Elium®. Vacuum assisted resin infusion (VARI) process is chosen as a cost effective manufacturing technique. Process parameters optimisation is required for thin NCFs due to intrinsic resistance it offers to the polymer flow. Cycles of repetitive manufacturing studies were carried out to optimise the NCF-thermoset (TS) and NCF with novel reactive thermoplastic (TP) resin. It was noticed that the controlled and optimised usage of flow mesh, vacuum level and flow speed during the resin infusion plays a significant part in deciding the final quality of the fabricated composites. The material selections, the challenges met during the manufacturing and the methods to overcome these are deliberated in this paper. An optimal three stage vacuum technique developed to manufacture the TP and TS composites with high fibre volume and lower void content is established and presented. PMID:28772654

Optimizing Polymer Infusion Process for Thin Ply Textile Composites with Novel Matrix System.

PubMed

Bhudolia, Somen K; Perrotey, Pavel; Joshi, Sunil C

2017-03-15

For mass production of structural composites, use of different textile patterns, custom preforming, room temperature cure high performance polymers and simplistic manufacturing approaches are desired. Woven fabrics are widely used for infusion processes owing to their high permeability but their localised mechanical performance is affected due to inherent associated crimps. The current investigation deals with manufacturing low-weight textile carbon non-crimp fabrics (NCFs) composites with a room temperature cure epoxy and a novel liquid Methyl methacrylate (MMA) thermoplastic matrix, Elium ® . Vacuum assisted resin infusion (VARI) process is chosen as a cost effective manufacturing technique. Process parameters optimisation is required for thin NCFs due to intrinsic resistance it offers to the polymer flow. Cycles of repetitive manufacturing studies were carried out to optimise the NCF-thermoset (TS) and NCF with novel reactive thermoplastic (TP) resin. It was noticed that the controlled and optimised usage of flow mesh, vacuum level and flow speed during the resin infusion plays a significant part in deciding the final quality of the fabricated composites. The material selections, the challenges met during the manufacturing and the methods to overcome these are deliberated in this paper. An optimal three stage vacuum technique developed to manufacture the TP and TS composites with high fibre volume and lower void content is established and presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Juan; Zhou, Yufan; Sui, Xiao

Switchable ionic liquids (SWIL) play an important role in green chemistry. Due to the nature of SWIL chemistry, such as air sensitivity and pressure and temperature dependence, it is difficult to characterize SWIL using vacuum-based surface techniques. The fully CO2 loaded and none-loaded DBU and hexanol mixtures, a SWIL system, were analyzed in situ by time-of-flight secondary ion mass spectrometry (ToF-SIMS) coupled with the System for Analysis at the Liquid Vacuum Interface (SALVI), respectively. The DBU/Hexanol/CO2 SWIL was injected into the microchannel before liquid SIMS analysis. Bi3+ primary ion beam was used. The positive and negative spectra of the SWILmore » chemical components are presented. The characteristic peaks m/z 153 (reduced DBU) in the positive mode and m/z 101 (oxidized hexanol) in negative mode were observed. In addition, ion pair peaks including m/z 253, 319, 305, 451 in the positive mode and m/z 145, 223, 257 in the negative mode are first observed using this approach. These results demonstrate that the SALVI microfluidic reactor enables the vacuum-based surface technique (i.e., ToF-SIMS) for in situ characterization of challenging liquid samples such as ionic liquids.« less

Process for improving the energy density of feedstocks using formate salts

DOEpatents

Wheeler, Marshall Clayton; van Heiningen, Adriaan R.P.; Case, Paige A.

2015-09-01

Methods of forming liquid hydrocarbons through thermal deoxygenation of cellulosic compounds are disclosed. Aspects cover methods including the steps of mixing a levulinic acid salt-containing feedstock with a formic acid salt, exposing the mixture to a high temperature condition to form hydrocarbon vapor, and condensing the hydrocarbon vapor to form liquid hydrocarbons, where both the formic acid salt and the levulinic acid salt-containing feedstock decompose at the high temperature condition and wherein one or more of the mixing, exposing, and condensing steps is carried out a pressure between about vacuum and about 10 bar.

First stage of reaction of molten Al with MgO substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgiel, J., E-mail: j.morgiel@imim.pl; Sobczak, N.; Motor Transport Institute, 80 Jagiellońska St., 03-301 Warsaw

The Al/MgO couple was produced in vacuum (~ 5 × 10{sup −} {sup 4} Pa) by contact heating from RT up to 1000 °C and holding at that temperature for 1 h of a small 4 × 4 × 4 mm aluminium (5 N) sample placed on the [100] MgO single crystal substrate. TEM observations backed with electron diffraction analysis indicated that the interaction between liquid aluminium and MgO starts from a redox reaction producing a continuous layer of MgAl{sub 2}O{sub 4} spinel on the substrate surface. Its growth is controlled by solid state out-diffusion of magnesium and oxygen towardsmore » the surface being in contact with liquid metal. The thickening of spinel layer is accompanied by its cracking and infiltration with aluminium. The above process enables local dissolution of the MgO substrate and formation in it of a thin region of interpenetrating metallic channels walled with spinel. The removal of dissolved magnesium through open aluminium channels towards the drop and to vacuum locally produces areas of aluminium enriched with dissolved oxygen, which results in the nucleation of α-Al{sub 2}O{sub 3} at spinel clad walls. The growth of α-Al{sub 2}O{sub 3} is controlled only by the dissolution rate of MgO by aluminium, liquid state diffusion of Mg to drop/vacuum and oxygen to the front of the of α-Al{sub 2}O{sub 3} crystallites growing into MgO substrate. - Highlights: • New unique evidence of first stages of interaction of liquid Al with MgO substrates • Interaction of liquid Al with MgO starts with the formation of a layer MgAl{sub 2}O{sub 4}. • Growth of MgAl{sub 2}O{sub 4} is slow as controlled by solid state out-diffusion of Mg and O. • MgAl{sub 2}O{sub 4} serves as a nucleation site for Al{sub 2}O{sub 3} and consumed by it soon after. • Growth of Al{sub 2}O{sub 3} is fast as controlled by diffusion in liquid state.« less

A 2.5 Gigawatt Liquid Dielectric Coaxial Pulse Forming Line

DTIC Science & Technology

1987-06-01

operation. The fuses provide protection against long term faults. The 3 phase vacuum contactor is a convenient means of remotely applying or...is electronically sensed and the vacuum contactor opens thereby interrupting the input power. The opening time of the vacuum contactor is less than...less than 5 microseconds and at the same time a trigger signal is sent to the vacuum contactor which opens and interrupts the primary power. The PFL

Treatment of evaporator condensates by pervaporation

DOEpatents

Blume, Ingo; Baker, Richard W.

1990-01-01

A pervaporation process for separating organic contaminants from evaporator condensate streams is disclosed. The process employs a permselective membrane that is selectively permeable to an organic component of the condensate. The process involves contacting the feed side of the membrane with a liquid condensate stream, and withdrawing from the permeate side a vapor enriched in the organic component. The driving force for the process is the in vapor pressure across the membrane. This difference may be provided for instance by maintaining a vacuum on the permeate side, or by condensing the permeate. The process offers a simple, economic alternative to other separation techniques.

Flexible automated approach for quantitative liquid handling of complex biological samples.

PubMed

Palandra, Joe; Weller, David; Hudson, Gary; Li, Jeff; Osgood, Sarah; Hudson, Emily; Zhong, Min; Buchholz, Lisa; Cohen, Lucinda H

2007-11-01

A fully automated protein precipitation technique for biological sample preparation has been developed for the quantitation of drugs in various biological matrixes. All liquid handling during sample preparation was automated using a Hamilton MicroLab Star Robotic workstation, which included the preparation of standards and controls from a Watson laboratory information management system generated work list, shaking of 96-well plates, and vacuum application. Processing time is less than 30 s per sample or approximately 45 min per 96-well plate, which is then immediately ready for injection onto an LC-MS/MS system. An overview of the process workflow is discussed, including the software development. Validation data are also provided, including specific liquid class data as well as comparative data of automated vs manual preparation using both quality controls and actual sample data. The efficiencies gained from this automated approach are described.

Catalytic multi-stage process for hydroconversion and refining hydrocarbon feeds

DOEpatents

Comolli, Alfred G.; Lee, Lap-Keung

2001-01-01

A multi-stage catalytic hydrogenation and hydroconversion process for heavy hydrocarbon feed materials such as coal, heavy petroleum fractions, and plastic waste materials. In the process, the feedstock is reacted in a first-stage, back-mixed catalytic reactor with a highly dispersed iron-based catalyst having a powder, gel or liquid form. The reactor effluent is pressure-reduced, vapors and light distillate fractions are removed overhead, and the heavier liquid fraction is fed to a second stage back-mixed catalytic reactor. The first and second stage catalytic reactors are operated at 700-850.degree. F. temperature, 1000-3500 psig hydrogen partial pressure and 20-80 lb./hr per ft.sup.3 reactor space velocity. The vapor and light distillates liquid fractions removed from both the first and second stage reactor effluent streams are combined and passed to an in-line, fixed-bed catalytic hydrotreater for heteroatom removal and for producing high quality naphtha and mid-distillate or a full-range distillate product. The remaining separator bottoms liquid fractions are distilled at successive atmospheric and vacuum pressures, low and intermediate-boiling hydrocarbon liquid products are withdrawn, and heavier distillate fractions are recycled and further upgraded to provide additional low-boiling hydrocarbon liquid products. This catalytic multistage hydrogenation process provides improved flexibility for hydroprocessing the various carbonaceous feedstocks and adjusting to desired product structures and for improved economy of operations.

Cyclic membrane separation process

DOEpatents

Bowser, John

2004-04-13

A cyclic process for controlling environmental emissions of volatile organic compounds (VOC) from vapor recovery in storage and dispensing operations of liquids maintains a vacuum in the storage tank ullage. In one of a two-part cyclic process ullage vapor is discharged through a vapor recovery system in which VOC are stripped from vented gas with a selectively gas permeable membrane. In the other part, the membrane is inoperative while gas pressure rises in the ullage. Ambient air is charged to the membrane separation unit during the latter part of the cycle.

Composite Structures and Materials Research at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Starnes, James H., Jr.; Dexter, H. Benson; Johnston, Norman J.; Ambur, Damodar R.; Cano, roberto J.

2003-01-01

A summary of recent composite structures and materials research at NASA Langley Research Center is presented. Fabrication research to develop low-cost automated robotic fabrication procedures for thermosetting and thermoplastic composite materials, and low-cost liquid molding processes for preformed textile materials is described. Robotic fabrication procedures discussed include ply-by-ply, cure-on-the-fly heated placement head and out-of-autoclave electron-beam cure methods for tow and tape thermosetting and thermoplastic materials. Liquid molding fabrication processes described include Resin Film Infusion (RFI), Resin Transfer Molding (RTM) and Vacuum-Assisted Resin Transfer Molding (VARTM). Results for a full-scale composite wing box are summarized to identify the performance of materials and structures fabricated with these low-cost fabrication methods.

Composite Structures and Materials Research at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Starnes, James H., Jr.; Dexter, H. Benson; Johnston, Norman J.; Ambur, Damodar R.; Cano, Roberto J.

2001-01-01

A summary of recent composite structures and materials research at NASA Langley Research Center is presented. Fabrication research to develop low-cost automated robotic fabrication procedures for thermosetting and thermoplastic composite materials, and low-cost liquid molding processes for preformed textile materials is described. Robotic fabrication procedures discussed include ply-by-ply, cure-on-the-fly heated placement head and out-of-autoclave electron-beam cure methods for tow and tape thermosetting and thermoplastic materials. Liquid molding fabrication processes described include Resin Film Infusion (RFI) Resin Transfer Molding (RTM) and Vacuum-Assisted Resin Transfer Molding (VARTM). Results for a full-scale composite wing box are summarized to identify the performance of materials and structures fabricated with these low-cost fabrication methods.

Liquid-Crystal Thermosets, a New Generation of High-Performance Liquid-Crystal Polymers

NASA Technical Reports Server (NTRS)

Dingemans, Theo; Weiser, Erik; Hou, Tan; Jensen, Brian; St. Clair, Terry

2004-01-01

One of the major challenges for NASA's next-generation reusable-launch-vehicle (RLV) program is the design of a cryogenic lightweight composite fuel tank. Potential matrix resin systems need to exhibit a low coefficient of thermal expansion (CTE), good mechanical strength, and excellent barrier properties at cryogenic temperatures under load. In addition, the resin system needs to be processable by a variety of non-autoclavable techniques, such as vacuum-bag curing, resin-transfer molding (RTM), vacuum-assisted resin-transfer molding (VaRTM), resin-film infusion (RFI), pultrusion, and advanced tow placement (ATP). To meet these requirements, the Advanced Materials and Processing Branch (AMPB) at NASA Langley Research Center developed a new family of wholly aromatic liquid-crystal oligomers that can be processed and thermally cross-linked while maintaining their liquid-crystal order. All the monomers were polymerized in the presence of a cross-linkable unit by use of an environmentally benign melt-condensation technique. This method does not require hazardous solvents, and the only side product is acetic acid. The final product can be obtained as a powder or granulate and has an infinite shelf life. The obtained oligomers melt into a nematic phase and do not exhibit isotropization temperatures greater than the temperatures of decomposition (Ti > T(sub dec)). Three aromatic formulations were designed and tested and included esters, ester-amides, and ester-imides. One of the major advantages of this invention, named LaRC-LCR or Langley Research Center-Liquid Crystal Resin, is the ability to control a variety of resin characteristics, such as melting temperature, viscosity, and the cross-link density of the final part. Depending on the formulation, oligomers can be prepared with melt viscosities in the range of 10-10,000 poise (100 rad/s), which can easily be melt-processed using a variety of composite-processing techniques. This capability provides NASA with custom-made matrix resins that meet the required processing conditions for the fabrication of textile composites. Once the resin is in place, the temperature is raised to 375 C and the oligomers are cross-linked into a high-glass-transition-temperature (Tg) nematic network without releasing volatiles. The mechanical properties of the fully crosslinked, composite articles are comparable to typical composites based on commercially available epoxy resins.

Thermal Vacuum Integrated System Test at B-2

NASA Technical Reports Server (NTRS)

Kudlac, Maureen T.; Weaver, Harold F.; Cmar, Mark D.

2012-01-01

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) Plum Brook Station (PBS) Space Propulsion Research Facility, commonly referred to as B-2, is NASA s third largest thermal vacuum facility. It is the largest designed to store and transfer large quantities of liquid hydrogen and liquid oxygen, and is perfectly suited to support developmental testing of chemical propulsion systems as well as fully integrated stages. The facility is also capable of providing thermal-vacuum simulation services to support testing of large lightweight structures, Cryogenic Fluid Management (CFM) systems, electric propulsion test programs, and other In-Space propulsion programs. A recently completed integrated system test demonstrated the refurbished thermal vacuum capabilities of the facility. The test used the modernized data acquisition and control system to monitor the facility during pump down of the vacuum chamber, operation of the liquid nitrogen heat sink (or cold wall) and the infrared lamp array. A vacuum level of 1.3x10(exp -4)Pa (1x10(exp -6)torr) was achieved. The heat sink provided a uniform temperature environment of approximately 77 K (140deg R) along the entire inner surface of the vacuum chamber. The recently rebuilt and modernized infrared lamp array produced a nominal heat flux of 1.4 kW/sq m at a chamber diameter of 6.7 m (22 ft) and along 11 m (36 ft) of the chamber s cylindrical vertical interior. With the lamp array and heat sink operating simultaneously, the thermal systems produced a heat flux pattern simulating radiation to space on one surface and solar exposure on the other surface. The data acquired matched pretest predictions and demonstrated system functionality.

Reactions of solvated electrons initiated by sodium atom ionization at the vacuum-liquid interface.

PubMed

Alexander, William A; Wiens, Justin P; Minton, Timothy K; Nathanson, Gilbert M

2012-03-02

Solvated electrons are powerful reagents in the liquid phase that break chemical bonds and thereby create additional reactive species, including hydrogen atoms. We explored the distinct chemistry that ensues when electrons are liberated near the liquid surface rather than within the bulk. Specifically, we detected the products resulting from exposure of liquid glycerol to a beam of sodium atoms. The Na atoms ionized in the surface region, generating electrons that reacted with deuterated glycerol, C(3)D(5)(OD)(3), to produce D atoms, D(2), D(2)O, and glycerol fragments. Surprisingly, 43 ± 4% of the D atoms traversed the interfacial region and desorbed into vacuum before attacking C-D bonds to produce D(2).

1000 X Difference Between Current Displays and Capability of Human Visual System: Payoff Potential for Affordable Defense Systems

DTIC Science & Technology

2000-01-01

second tier technologies: digital micromirror devices (DMD); alternating current gas plasma (ACGP); inorganic electroluminescent (EL, TFEL, AMEL... Micromirror Device (DMD) - Alternating Current Gas Plasma (ACGP) - Electroluminescent (EL, TFEL, AMEL) - Vacuum Fluorescent Display (VFD) - Inorganic Light...Instruments Digital Micromirror Device (DMD) Digital Light Processing technology and another, the Qualcomm/Hughes-JVC CRT/Liquid Crystal Light Valve

Tuning charge carrier transport and optical birefringence in liquid-crystalline thin films: A new design space for organic light-emitting diodes.

PubMed

Keum, Chang-Min; Liu, Shiyi; Al-Shadeedi, Akram; Kaphle, Vikash; Callens, Michiel Koen; Han, Lu; Neyts, Kristiaan; Zhao, Hongping; Gather, Malte C; Bunge, Scott D; Twieg, Robert J; Jakli, Antal; Lüssem, Björn

2018-01-15

Liquid-crystalline organic semiconductors exhibit unique properties that make them highly interesting for organic optoelectronic applications. Their optical and electrical anisotropies and the possibility to control the alignment of the liquid-crystalline semiconductor allow not only to optimize charge carrier transport, but to tune the optical property of organic thin-film devices as well. In this study, the molecular orientation in a liquid-crystalline semiconductor film is tuned by a novel blading process as well as by different annealing protocols. The altered alignment is verified by cross-polarized optical microscopy and spectroscopic ellipsometry. It is shown that a change in alignment of the liquid-crystalline semiconductor improves charge transport in single charge carrier devices profoundly. Comparing the current-voltage characteristics of single charge carrier devices with simulations shows an excellent agreement and from this an in-depth understanding of single charge carrier transport in two-terminal devices is obtained. Finally, p-i-n type organic light-emitting diodes (OLEDs) compatible with vacuum processing techniques used in state-of-the-art OLEDs are demonstrated employing liquid-crystalline host matrix in the emission layer.

High specific surface area aerogel cryoadsorber for vacuum pumping applications

DOEpatents

Hill, Randal M.; Fought, Eric R.; Biltoft, Peter J.

2000-01-01

A cryogenic pumping system is provided, comprising a vacuum environment, an aerogel sorbent formed from a carbon aerogel disposed within the vacuum environment, and cooling means for cooling the aerogel sorbent sufficiently to adsorb molecules from the vacuum environment onto the aerogel sorbent. Embodiments of the invention include a liquid refrigerant cryosorption pump, a compressed helium cryogenic pump, a cryopanel and a Meissner coil, each of which uses carbon aerogel as a sorbent material.

Free Radical Polymerization of Styrene: A Radiotracer Experiment

ERIC Educational Resources Information Center

Mazza, R. J.

1975-01-01

Describes an experiment designed to acquaint the chemistry student with polymerization reactions, vacuum techniques, liquid scintillation counting, gas-liquid chromatography, and the handling of radioactive materials. (MLH)

Wet/Dry Vacuum Cleaner

NASA Technical Reports Server (NTRS)

Reimers, Harold; Andampour, Jay; Kunitser, Craig; Thomas, Ike

1995-01-01

Vacuum cleaner collects and retains dust, wet debris, and liquids. Designed for housekeeping on Space Station Freedom, it functions equally well in normal Earth Gravity or in microgravity. Generates acoustic noise at comfortably low levels and includes circuitry that reduces electromagnetic interference to other electronic equipment. Draws materials into bag made of hydrophobic sheet with layers of hydrophilic super-absorbing pads at downstream end material. Hydrophilic material can gel many times its own weight of liquid. Blower also provides secondary airflow to cool its electronic components.

Physico-chemical characterization of products from vacuum oil under delayed coking process by infrared spectroscopy and chemometrics methods

NASA Astrophysics Data System (ADS)

Meléndez, L. V.; Cabanzo, R.; Mejía-Ospino, E.; Guzmán, A.

2016-02-01

Eight vacuum residues and their delayed coking liquids products from Colombian crude were study by infrared spectroscopy with attenuated total reflectance (FTIR-ATR) and principal component analysis (PCA). For the samples the structural parameters of aromaticity factor (fa), alifaticity (A2500-3100cm-1), aromatic condensation degree (GCA), length of aliphatic chains (LCA) and aliphatic chain length associated with aromatic (LACAR) were determined through the development of a methodology, which includes the previous processing of spectroscopy data, identifying the regions in the IR spectra of greatest variance using PCA and molecules patterns. The parameters were compared with the results obtained from proton magnetic resonance (1H-NMR) and 13C-NMR. The results showed the influence and correlation of structural parameters with some physicochemical properties such as API gravity, weight percent sulphur (% S) and Conradson carbon content (% CCR)

ASME Section VIII Recertification of a 33,000 Gallon Vacuum-jacketed LH2 Storage Vessel for Densified Hydrogen Testing at NASA Kennedy Space Center

NASA Technical Reports Server (NTRS)

Swanger, Adam M.; Notardonato, William U.; Jumper, Kevin M.

2015-01-01

The Ground Operations Demonstration Unit for Liquid Hydrogen (GODU-LH2) has been developed at NASA Kennedy Space Center in Florida. GODU-LH2 has three main objectives: zero-loss storage and transfer, liquefaction, and densification of liquid hydrogen. A cryogenic refrigerator has been integrated into an existing, previously certified, 33,000 gallon vacuum-jacketed storage vessel built by Minnesota Valley Engineering in 1991 for the Titan program. The dewar has an inner diameter of 9.5 and a length of 71.5; original design temperature and pressure ranges are -423 F to 100 F and 0 to 95 psig respectively. During densification operations the liquid temperature will be decreased below the normal boiling point by the refrigerator, and consequently the pressure inside the inner vessel will be sub-atmospheric. These new operational conditions rendered the original certification invalid, so an effort was undertaken to recertify the tank to the new pressure and temperature requirements (-12.7 to 95 psig and -433 F to 100 F respectively) per ASME Boiler and Pressure Vessel Code, Section VIII, Division 1. This paper will discuss the unique design, analysis and implementation issues encountered during the vessel recertification process.

On the origin of the electrostatic potential difference at a liquid-vacuum interface.

PubMed

Harder, Edward; Roux, Benoît

2008-12-21

The microscopic origin of the interface potential calculated from computer simulations is elucidated by considering a simple model of molecules near an interface. The model posits that molecules are isotropically oriented and their charge density is Gaussian distributed. Molecules that have a charge density that is more negative toward their interior tend to give rise to a negative interface potential relative to the gaseous phase, while charge densities more positive toward their interior give rise to a positive interface potential. The interface potential for the model is compared to the interface potential computed from molecular dynamics simulations of the nonpolar vacuum-methane system and the polar vacuum-water interface system. The computed vacuum-methane interface potential from a molecular dynamics simulation (-220 mV) is captured with quantitative precision by the model. For the vacuum-water interface system, the model predicts a potential of -400 mV compared to -510 mV, calculated from a molecular dynamics simulation. The physical implications of this isotropic contribution to the interface potential is examined using the example of ion solvation in liquid methane.

Direct electroplating of copper on tantalum from ionic liquids in high vacuum: origin of the tantalum oxide layer.

PubMed

Schaltin, Stijn; D'Urzo, Lucia; Zhao, Qiang; Vantomme, André; Plank, Harald; Kothleitner, Gerald; Gspan, Christian; Binnemans, Koen; Fransaer, Jan

2012-10-21

In this paper, it is shown that high vacuum conditions are not sufficient to completely remove water and oxygen from the ionic liquid 1-ethyl-3-methylimidazolium chloride. Complete removal of water demands heating above 150 °C under reduced pressure, as proven by Nuclear Reaction Analysis (NRA). Dissolved oxygen gas can only be removed by the use of an oxygen scavenger such as hydroquinone, despite the fact that calculations show that oxygen should be removed completely by the applied vacuum conditions. After applying a strict drying procedure and scavenging of molecular oxygen, it was possible to deposit copper directly on tantalum without the presence of an intervening oxide layer.

Integrated Cryogenic Propulsion Test Article Thermal Vacuum Hotfire Testing

NASA Technical Reports Server (NTRS)

Morehead, Robert L.; Melcher, J. C.; Atwell, Matthew J.; Hurlbert, Eric A.

2017-01-01

In support of a facility characterization test, the Integrated Cryogenic Propulsion Test Article (ICPTA) was hotfire tested at a variety of simulated altitude and thermal conditions in the NASA Glenn Research Center Plum Brook Station In-Space Propulsion Thermal Vacuum Chamber (formerly B2). The ICPTA utilizes liquid oxygen and liquid methane propellants for its main engine and four reaction control engines, and uses a cold helium system for tank pressurization. The hotfire test series included high altitude, high vacuum, ambient temperature, and deep cryogenic environments, and several hundred sensors on the vehicle collected a range of system level data useful to characterize the operation of an integrated LOX/Methane spacecraft in the space environment - a unique data set for this propellant combination.

Printable CIGS thin film solar cells

NASA Astrophysics Data System (ADS)

Fan, Xiaojuan

2014-03-01

Among the various thin film solar cells in the market, CuInGaSe thin film cells have been considered as the most promising alternatives to silicon solar cells because of their high photo-electricity efficiency, reliability, and stability. However, many fabrication of CIGS thin film are based on vacuum processes such as evaporation sputtering techniques which are not cost efficient. This work develops a method using paste or ink liquid spin-coated on glass that would be to conventional ways in terms of cost effective, non-vacuum needed, quick processing. A mixture precursor was prepared by dissolving appropriate amounts of chemicals. After the mixture solution was cooled, a viscous paste prepared and ready for spin-coating process. A slight bluish CIG thin film substrate was then put in a tube furnace with evaporation of metal Se by depositing CdS layer and ZnO nanoparticle thin film coating to a solar cell fabrication. Structure, absorption spectrum, and photo-conversion efficiency for the as-grown CIGS thin film solar cell under study.

Recombination device for storage batteries

DOEpatents

Kraft, H.; Ledjeff, K.

1984-01-01

A recombination device including a gas-tight enclosure connected to receive the discharge gases from a rechargeable storage battery. Catalytic material for the recombination of hydrogen and oxygen to form water is supported within the enclosure. The enclosure is sealed from the atmosphere by a liquid seal including two vertical chambers interconnected with an inverted U-shaped overflow tube. The first chamber is connected at its upper portion to the enclosure and the second chamber communicates at its upper portion with the atmosphere. If the pressure within the enclosure differs as overpressure or vacuum by more than the liquid level, the liquid is forced into one of the two chambers and the overpressure is vented or the vacuum is relieved. The recombination device also includes means for returning recombined liquid to the battery and for absorbing metal hydrides.

Recombination device for storage batteries

DOEpatents

Kraft, Helmut; Ledjeff, Konstantin

1985-01-01

A recombination device including a gas-tight enclosure connected to receive he discharge gases from a rechargeable storage battery. Catalytic material for the recombination of hydrogen and oxygen to form water is supported within the enclosure. The enclosure is sealed from the atmosphere by a liquid seal including two vertical chambers interconnected with an inverted U-shaped overflow tube. The first chamber is connected at its upper portion to the enclosure and the second chamber communicates at its upper portion with the atmosphere. If the pressure within the enclosure differs as overpressure or vacuum by more than the liquid level, the liquid is forced into one of the two chambers and the overpressure is vented or the vacuum is relieved. The recombination device also includes means for returning recombined liquid to the battery and for absorbing metal hydrides.

Breakthrough to Non-Vacuum Deposition of Single-Crystal, Ultra-Thin, Homogeneous Nanoparticle Layers: A Better Alternative to Chemical Bath Deposition and Atomic Layer Deposition

PubMed Central

Liao, Yu-Kuang; Liu, Yung-Tsung; Hsieh, Dan-Hua; Shen, Tien-Lin; Hsieh, Ming-Yang; Tzou, An-Jye; Chen, Shih-Chen; Tsai, Yu-Lin; Lin, Wei-Sheng; Chan, Sheng-Wen; Shen, Yen-Ping; Cheng, Shun-Jen; Chen, Chyong-Hua; Wu, Kaung-Hsiung; Chen, Hao-Ming; Kuo, Shou-Yi; Charlton, Martin D. B.; Hsieh, Tung-Po; Kuo, Hao-Chung

2017-01-01

Most thin-film techniques require a multiple vacuum process, and cannot produce high-coverage continuous thin films with the thickness of a few nanometers on rough surfaces. We present a new ”paradigm shift” non-vacuum process to deposit high-quality, ultra-thin, single-crystal layers of coalesced sulfide nanoparticles (NPs) with controllable thickness down to a few nanometers, based on thermal decomposition. This provides high-coverage, homogeneous thickness, and large-area deposition over a rough surface, with little material loss or liquid chemical waste, and deposition rates of 10 nm/min. This technique can potentially replace conventional thin-film deposition methods, such as atomic layer deposition (ALD) and chemical bath deposition (CBD) as used by the Cu(In,Ga)Se2 (CIGS) thin-film solar cell industry for decades. We demonstrate 32% improvement of CIGS thin-film solar cell efficiency in comparison to reference devices prepared by conventional CBD deposition method by depositing the ZnS NPs buffer layer using the new process. The new ZnS NPs layer allows reduction of an intrinsic ZnO layer, which can lead to severe shunt leakage in case of a CBD buffer layer. This leads to a 65% relative efficiency increase. PMID:28383488

Optimization of pectin extraction and antioxidant activities from Jerusalem artichoke

NASA Astrophysics Data System (ADS)

Liu, Shengyi; Shi, Xuejie; Xu, Lanlan; Yi, Yuetao

2016-03-01

Jerusalem artichoke is an economic crop widely planted in saline-alkaline soil. The use of Jerusalem artichoke is of great significance. In this study, the response surface method was employed to optimize the effects of processing variables (extraction temperature, pH, extraction time, and liquid-to-solid ratio) on the yield of Jerusalem artichoke pectin. Under the optimal extraction conditions: pH 1.52, 63.62 min, 100°C and a liquid-to-solid ratio of 44.4 mL/g, the maximum pectin yield was predicted to be 18.76%. Experiments were conducted under these optimal conditions and a pectin yield of 18.52±0.90% was obtained, which validated the model prediction. The effects of diff erent drying methods (freeze drying, spray drying and vacuum drying) on the properties of Jerusalem artichoke pectin were evaluated and they were compared with apple pectin. FTIR spectral analysis showed no major structural diff erences in Jerusalem artichoke pectin samples produced by various drying treatments. The antioxidant activities of pectin dried by diff erent methods were investigated using in vitro hydroxyl and DPPH radical scavenging systems. The results revealed that the activities of spray dried pectin (SDP) and apple pectin (AP) were stronger than those of vacuum oven dried pectin (ODP) and vacuum freeze dried pectin (FDP). Therefore compared with the other two drying methods, the spray drying method was the best.

Cryopumping of hydrogen in vacuum chambers is aided by catalytic oxidation of hydrogen

NASA Technical Reports Server (NTRS)

Childs, J. H.; Grobman, J.; Rayle, W.

1964-01-01

Vacuum test facilities are required for high speed cryopumping of gaseous hydrogen at low pressures. One method involves the catalytic oxidation of hydrogen and condensation of the resulting water on a liquid nitrogen-cooled surface.

Experiments on microjets of undercooled liquid hydrogen

NASA Astrophysics Data System (ADS)

Fernández, José M.; Kühnel, Matthias; Tejeda, Guzmán; Kalinin, Anton; Grisenti, Robert E.; Montero, Salvador

2012-11-01

Novel experiments on liquid microjets (filaments) of hydrogen and deuterium, carried out at the Laboratory of Molecular Fluid Dynamics of the IEM, are reported. These filaments, less than 10 microns in diameter, are an ideal medium to produce highly undercooled liquid samples and to investigate the homogeneous solidification process, free from wall effects. The filaments exit from cryogenic capillary nozzles into a vacuum chamber, to cool down very fast by surface evaporation. Finite size radius leads to a temperature gradient across the filament, determined by thermal conductivity, and, possibly, to a velocity gradient as well. The filaments are monitored by laser shadowgraphy, and analyzed by means of high performance Raman spectroscopy. Real-time measurements in the rotational and vibrational spectral regions reveal the structure and temperature along the filaments, allowing to track the crystal growth process. The high spatial resolution of Raman spectroscopy allows observing in situ the structural changes of the liquid microjets, with a time resolution of ˜ 10 ns. The filaments of pure para-H2 can be cooled down to 9 K (65% of its melting point at 13.8 K), while staying liquid, before eventually solidifying into a metastable polymorph. Crystallization kinetics revealed a growth rate of 33 cm/s, much higher than expected for a thermally activated process. The time and spatial control attained in these experiments offers new opportunities for investigating the processes of nonequilibrium phase transformations in undercooled fluids, as well as the propagation of liquid jets into a rarefied gas media.

Overview of High Power Vacuum Dry RF Load Designs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krasnykh, Anatoly

2015-08-27

A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is tomore » use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.« less

Radiation-thermometric study of isolated hot molten metal spheres by containerless and contactless measurement techniques

NASA Astrophysics Data System (ADS)

Lee, G. W.; Jeon, S.; Park, C.; Kang, D. H.; Choi, B. I.; Park, S. N.

2013-09-01

An electrostatic levitation (ESL) device is developed to study the radiation-properties of liquid metals at high temperature. The technique provides good advantage, such as fast response of temperature change on a sample, clear features of recalescence and plateau during freezing, no contamination or no reaction with environment, easy control of supercooling deducing hypercooling limit, and relatively simple analysis of thermodynamic quantities because of only radiative cooling process under vacuum. In this study, we could obtain a hypercooling limit (i.e., maximum supercooling) of liquid Ti, 341 K using the ESL. An accurate ratio of the specific heat to total hemispherical emissivity of liquid Ti was obtained by Stefan-Boltzmann law. Then, the specific heat and total hemispherical emissivity of Ti liquid metal can be estimated with the hypercooling limit and known fusion enthalpy values of Ti, which has been rarely reported.

Review and test of chilldown methods for space-based cryogenic tanks

NASA Astrophysics Data System (ADS)

Chato, David J.; Sanabria, Rafael

The literature for tank chilldown methods applicable to cryogenic tankage in the zero gravity environment of earth orbit is reviewed. One method is selected for demonstration in a ground based test. The method selected for investigation was the charge-hold-vent method which uses repeated injection of liquid slugs, followed by a hold to allow complete vaporization of the liquid and a vent of the tank to space vacuum to cool tankage to the desired temperature. The test was conducted on a 175 cubic foot, 2219 aluminum walled tank weighing 329 pounds, which was previously outfitted with spray systems to test nonvented fill technologies. To minimize hardware changes, a simple control-by-pressure scheme was implemented to control injected liquid quantities. The tank cooled from 440 R sufficiently in six charge-hold-vent cycles to allow a complete nonvented fill of the test tank. Liquid hydrogen consumed in the process is estimated at 32 pounds.

Review and test of chilldown methods for space-based cryogenic tanks

NASA Technical Reports Server (NTRS)

Chato, David J.; Sanabria, Rafael

1991-01-01

The literature for tank chilldown methods applicable to cryogenic tankage in the zero gravity environment of earth orbit is reviewed. One method is selected for demonstration in a ground based test. The method selected for investigation was the charge-hold-vent method which uses repeated injection of liquid slugs, followed by a hold to allow complete vaporization of the liquid and a vent of the tank to space vacuum to cool tankage to the desired temperature. The test was conducted on a 175 cubic foot, 2219 aluminum walled tank weighing 329 pounds, which was previously outfitted with spray systems to test nonvented fill technologies. To minimize hardware changes, a simple control-by-pressure scheme was implemented to control injected liquid quantities. The tank cooled from 440 R sufficiently in six charge-hold-vent cycles to allow a complete nonvented fill of the test tank. Liquid hydrogen consumed in the process is estimated at 32 pounds.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Li; Zhu, Zihua; Yu, Xiao-Ying

In this study, we report new results of in situ study of 5 nm goat anti-mouse IgG gold nanoparticles in a novel portable vacuum compatible microfluidic device using scanning electron microscope (SEM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The unique feature of the liquid flow cell is that the detection window is open to the vacuum allowing direct probing of the liquid surface. The flow cell is composed of a silicon nitride (SiN) membrane and polydimethylsiloxane (PDMS), and it is fully compatible with vacuum operations for surface analysis. The aperture can be drilled through the 100 nm SiN membranemore » using a focused ion beam. Characteristic signals of the conjugated gold nanoparticles were successfully observed through the aperture by both energy-dispersive X-ray spectroscopy (EDX) in SEM and ToF-SIMS. Comparison was also made among wet samples, dry samples, and liquid sample in the flow cell using SEM/EDX. Stronger gold signal can be observed in our novel portable device by SEM/EDX compared with the wet or dry samples, respectively. Our results indicate that analyses of the nanoparticle components are better made in their native liquid environment. This is made possible using our unique microfluidic flow cell.« less

46 CFR 162.017-2 - Type.

Code of Federal Regulations, 2013 CFR

2013-10-01

... APPROVAL ENGINEERING EQUIPMENT General Provisions; Valves, Pressure-Vacuum Relief, for Tank Vessels § 162.017-2 Type. This specification covers the design and construction of pressure-vacuum relief valves intended for use in venting systems on all tank vessels transporting inflammable or combustible liquids...

46 CFR 162.017-2 - Type.

Code of Federal Regulations, 2014 CFR

2014-10-01

... APPROVAL ENGINEERING EQUIPMENT General Provisions; Valves, Pressure-Vacuum Relief, for Tank Vessels § 162.017-2 Type. This specification covers the design and construction of pressure-vacuum relief valves intended for use in venting systems on all tank vessels transporting inflammable or combustible liquids...

46 CFR 162.017-2 - Type.

Code of Federal Regulations, 2012 CFR

2012-10-01

... APPROVAL ENGINEERING EQUIPMENT General Provisions; Valves, Pressure-Vacuum Relief, for Tank Vessels § 162.017-2 Type. This specification covers the design and construction of pressure-vacuum relief valves intended for use in venting systems on all tank vessels transporting inflammable or combustible liquids...

A highly modular beamline electrostatic levitation facility, optimized for in situ high-energy x-ray scattering studies of equilibrium and supercooled liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mauro, N.A.; Kelton, K.F.

2011-10-27

High-energy x-ray diffraction studies of metallic liquids provide valuable information about structural evolution on the atomic length scale, leading to insights into the origin of the nucleation barrier and the processes of supercooling and glass formation. The containerless processing of the beamline electrostatic levitation (BESL) facility allows coordinated thermophysical and structural studies of equilibrium and supercooled liquids to be made in a contamination-free, high-vacuum ({approx}10{sup -8} Torr) environment. To date, the incorporation of electrostatic levitation facilities into synchrotron beamlines has been difficult due to the large footprint of the apparatus and the difficulties associated with its transportation and implementation. Here,more » we describe a modular levitation facility that is optimized for diffraction studies of high-temperature liquids at high-energy synchrotron beamlines. The modular approach used in the apparatus design allows it to be easily transported and quickly setup. Unlike most previous electrostatic levitation facilities, BESL can be operated by a single user instead of a user team.« less

Novel Process of Simultaneous Removal of Nitric Oxide and Sulfur Dioxide Using a Vacuum Ultraviolet (VUV)-Activated O2/H2O/H2O2 System in A Wet VUV-Spraying Reactor.

PubMed

Liu, Yangxian; Wang, Qian; Pan, Jianfeng

2016-12-06

A novel process for NO and SO 2 simultaneous removal using a vacuum ultraviolet (VUV, with 185 nm wavelength)-activated O 2 /H 2 O/H 2 O 2 system in a wet VUV-spraying reactor was developed. The influence of different process variables on NO and SO 2 removal was evaluated. Active species (O 3 and ·OH) and liquid products (SO 3 2- , NO 2 - , SO 4 2- , and NO 3 - ) were analyzed. The chemistry and routes of NO and SO 2 removal were investigated. The oxidation removal system exhibits excellent simultaneous removal capacity for NO and SO 2 , and a maximum removal of 96.8% for NO and complete SO 2 removal were obtained under optimized conditions. SO 2 reaches 100% removal efficiency under most of test conditions. NO removal is obviously affected by several process variables. Increasing VUV power, H 2 O 2 concentration, solution pH, liquid-to-gas ratio, and O 2 concentration greatly enhances NO removal. Increasing NO and SO 2 concentration obviously reduces NO removal. Temperature has a dual impact on NO removal, which has an optimal temperature of 318 K. Sulfuric acid and nitric acid are the main removal products of NO and SO 2 . NO removals by oxidation of O 3 , O·, and ·OH are the primary routes. NO removals by H 2 O 2 oxidation and VUV photolysis are the complementary routes. A potential scaled-up removal process was also proposed initially.

Deformation mechanism of the Cryostat in the CADS Injector II

NASA Astrophysics Data System (ADS)

Yuan, Jiandong; Zhang, Bin; Wan, Yuqin; Sun, Guozhen; Bai, Feng; Zhang, Juihui; He, Yuan

2018-01-01

Thermal contraction and expansion of the Cryostat will affect its reliability and stability. To optimize and upgrade the Cryostat, we analyzed the heat transfer in a cryo-vacuum environment from the theoretical point first. The simulation of cryo-vacuum deformation based on a finite element method was implemented respectively. The completed measurement based on a Laser Tracker and a Micro Alignment Telescope was conducted to verify its correctness. The monitored deformations were consistent with the simulated ones. After the predictable deformations in vertical direction have been compensated, the superconducting solenoids and Half Wave Resonator cavities approached the ideal "zero" position under liquid helium conditions. These guaranteed the success of 25 MeV@170 uA continuous wave protons of Chinese accelerator driven subcritical system Injector II. By correlating the vacuum and cryo-deformation, we have demonstrated that the complete deformation was the superposition effect of the atmospheric pressure, gravity and thermal stress during both the process of cooling down and warming up. The results will benefit to an optimization for future Cryostat's design.

Coil-On-Plug Ignition for LOX/Methane Liquid Rocket Engines in Thermal Vacuum Environments

NASA Technical Reports Server (NTRS)

Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

2017-01-01

A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX) / liquid methane rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/methane propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. In order to successfully demonstrate ignition reliability in the vacuum conditions and eliminate corona discharge issues, a coil-on-plug ignition system has been developed. The ICPTA uses spark-plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark-plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp.-2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, Plum Brook testing demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/methane propulsion systems in future spacecraft.

CryoCart Restoration and Vacuum Pipe Construction

NASA Technical Reports Server (NTRS)

Chaidez, Mariana

2016-01-01

Propulsion systems that utilize hypergolic propellants have been used to power space vehicles since the beginning of the space program. Liquid methane and oxygen propulsion systems have emerged as an alternative and have proven to be more environmentally friendly. The incorporation of liquid methane/liquid oxygen (LOX) into the propulsion system has demonstrated an increase in engine performance, as well as a reduction in the volume, size and complexity of the system. Consequently, reducing the total mass of the vehicle which is a crucial aspect that is considered when planning space missions to both the Moon and Mars [1]. Project Morpheus has made significant advancements in liquid oxygen/liquid methane propulsion system technologies by incorporating a LOX/methane propulsion system to a vertical test bed. The vehicle consisted of a 5,000 lb main engine and four 20 lb remote control system (RCS) engines that utilize liquid methane/LOX as its propellant [1]. The vehicle completed successful flight testing at Kennedy Space Center in 2014 which marked the completion of the Morpheus project. Subsequent projects utilizing Morpheus' vertical test bed have been developed to make further advancements. One of the subsequent projects consisted of the addition of a smaller 2,000 lb main engine and a cold helium heat exchanger which would make it possible for a pressurant tank systems to be send to Mars or the Moon by significantly decreasing the overall mass and volume of the pressurant tank. The hot fire tests of the integrated system with the smaller main engine and cold helium heat exchanger were successful at sea level, but further studies are being conducted to better understand how the vertical test bed will behave under thermal-vacuum conditions. For this reason, the integrated vehicle will be taken to Plum Brook to be tested in a chamber capable of simulating these conditions. To ensure that the vehicle will function properly under vacuum conditions, testing will be first completed at the component level. During this process, the igniter of the main engine and the RCS thrusters will be tested under a vacuum. To complete the testing of the components, the test setup first needed to be finalized. The CryoCart is being used to feed the propellants to the test article. The CryoCart is a movable test set-up that was developed in 2009 to provide a mobile platform for testing oxygen/methane systems with hot-fire capability up to 100 lbf. The CryoCart consists of three different systems: Oxygen, Methane, and liquid Nitrogen. The Oxygen and Methane systems are placed into two different carts while the liquid nitrogen system is mainly located in the methane cart. Over the years, the CryoCart has been utilized for different projects and has undergone deterioration. For this reason, a new phase has been developed to rebuild it to working conditions once again. During my internship, I was aiding in the construction and restoration of the CryoCart. In the initial stages of the process, I updated the fluid and electrical schematics for the oxygen, methane, and test article systems. The original CryoCart consisted of an electrical panel that utilized electromechanical relays and a terminal to drive the igniter power and signal, as well as the main fuel and oxygen valves. This electrical panel connected to the CryoCart through various wire harnesses that could be found exiting from the CryoCart. First, it was determined how these harnesses connected to the electromechanical relays so that they worked correctly. Once the electrical system was understood, an alternative for the electromechanical relays and the Molex connectors used throughout the system was sought since these components can often prove to be unreliable. Solid State relays and MIL connectors were purchased to serve as replacements. Upon arrival of the parts, crimping and wiring was completed to install the new solid state relays and MIL connectors. During the replacement of the relays and connectors, system checks of the electrical system were ran to ensure that the system was working correctly. While completing system checks, the pressure transducers that were not functioning properly were also replaced and any issue with the wiring or signal was addressed. Once the electrical components were replaced, the restoration of the fluid system began. Parts of the tubing in the CryoCart had to be rebuild and often consisted of sizing, cutting, bending, filing, and sanding the tubing to prepare it to be flared. Many components had to be proof-tested to bring their certifications up to date, and several components had to be replaced. Various flex hoses, valves, and fittings were send to the Clean Lab because they were new, dirty, or had gone through proof-testing. Once they arrived from the cleaning lab they had to be put back to the system and leak checks and functional tests were conducted. In the Nitrogen system, the copper tubing located in the Oxygen cart was rebuild and Aerogel insulation was added to this section. A new gaseous nitrogen system was added to the CryoCart to purge the vacuum tube which will serve as the test chamber. Once the CryoCart was completed, construction of parts of the vacuum tube began. A flange was manufactured with welded fittings to hold the line of the vacuum pump as well as some extra fittings which will serve as extra inlets used to introduce fluid lines to the vacuum tube. Stress analysis was ran in this flange to ensure that it would not fail under vacuum conditions. The fluid lines leading from the air side of the vacuum to the test article were also constructed and added to the mount that had already been manufactured. Three different sets of tubing were constructed to accommodate the seven different RCS thruster and the main engine igniter that are going to be tested. Full electrical system checks were completed to ensure that all the wire harnesses and valves were functioning. Upon the completion of the CryoCart and the vacuum tube, hot fire testing for the RCS thrusters and the main engine igniter are going to begin. During this time any issues encountered with the engines or igniter will be addressed to ensure that the components function under vacuum conditions. After successful completion of testing, the vertical test bed, Morpheus, will be rebuilt and prepared to be sent to Plum Brook. In Plum Brook, the vehicle will be tested in the thermal-vacuum chamber to demonstrate that integrated lox-methane propulsion system operation in space-like conditions. This internship has allowed me the opportunity to gain valuable hands on experience and to develop skills that will aid in my education as well as in the workforce, while at the same time helping me determine that I would like to further pursue a career in propulsion engineering.

Quantitative force measurements in liquid using frequency modulation atomic force microscopy

NASA Astrophysics Data System (ADS)

Uchihashi, Takayuki; Higgins, Michael J.; Yasuda, Satoshi; Jarvis, Suzanne P.; Akita, Seiji; Nakayama, Yoshikazu; Sader, John E.

2004-10-01

The measurement of short-range forces with the atomic force microscope (AFM) typically requires implementation of dynamic techniques to maintain sensitivity and stability. While frequency modulation atomic force microscopy (FM-AFM) is used widely for high-resolution imaging and quantitative force measurements in vacuum, quantitative force measurements using FM-AFM in liquids have proven elusive. Here we demonstrate that the formalism derived for operation in vacuum can also be used in liquids, provided certain modifications are implemented. To facilitate comparison with previous measurements taken using surface forces apparatus, we choose a model system (octamethylcyclotetrasiloxane) that is known to exhibit short-ranged structural ordering when confined between two surfaces. Force measurements obtained are found to be in excellent agreement with previously reported results. This study therefore establishes FM-AFM as a powerful tool for the quantitative measurement of forces in liquid.

Manufacturing Solid Dosage Forms from Bulk Liquids Using the Fluid-bed Drying Technology.

PubMed

Qi, Jianping; Lu, Y I; Wu, Wei

2015-01-01

Solid dosage forms are better than liquid dosage forms in many ways, such as improved physical and chemical stability, ease of storage and transportation, improved handling properties, and patient compliance. Therefore, it is required to transform dosage forms of liquid origins into solid dosage forms. The functional approaches are to absorb the liquids by solid excipients or through drying. The conventional drying technologies for this purpose include drying by heating, vacuum-, freeze- and spray-drying, etc. Among these drying technologies, fluidbed drying emerges as a new technology that possesses unique advantages. Fluid-bed drying or coating is highly efficient in solvent removal, can be performed at relatively low temperatures, and is a one-step process to manufacture formulations in pellet forms. In this article, the status of the art of manufacturing solid dosage forms from bulk liquids by fluid-bed drying technology was reviewed emphasizing on its application in solid dispersion, inclusion complexes, self-microemulsifying systems, and various nanoscale drug delivery systems.

Site-Specific Preparation of Intact Solid–Liquid Interfaces by Label-Free In Situ Localization and Cryo-Focused Ion Beam Lift-Out

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zachman, Michael J.; Asenath-Smith, Emily; Estroff, Lara A.

Abstract Scanning transmission electron microscopy (STEM) allows atomic scale characterization of solid–solid interfaces, but has seen limited applications to solid–liquid interfaces due to the volatility of liquids in the microscope vacuum. Although cryo-electron microscopy is routinely used to characterize hydrated samples stabilized by rapid freezing, sample thinning is required to access the internal interfaces of thicker specimens. Here, we adapt cryo-focused ion beam (FIB) “lift-out,” a technique recently developed for biological specimens, to prepare intact internal solid–liquid interfaces for high-resolution structural and chemical analysis by cryo-STEM. To guide the milling process we introduce a label-freein situmethod of localizing subsurface structuresmore » in suitable materials by energy dispersive X-ray spectroscopy (EDX). Monte Carlo simulations are performed to evaluate the depth-probing capability of the technique, and show good qualitative agreement with experiment. We also detail procedures to produce homogeneously thin lamellae, which enable nanoscale structural, elemental, and chemical analysis of intact solid–liquid interfaces by analytical cryo-STEM. This work demonstrates the potential of cryo-FIB lift-out and cryo-STEM for understanding physical and chemical processes at solid–liquid interfaces.« less

Process for fabricating articles of tungsten-nickel-iron alloy

DOEpatents

Northcutt, Jr., Walter G.; Snyder, Jr., William B.

1976-01-01

A high density W--Ni--Fe alloy of composition 85-96% by weight W and the remainder Ni and Fe in a wt. ratio of 5:5-8:2 having enhanced mechanical properties is prepared by compacting the mixed powders, sintering the compact in reducing atmosphere to near theoretical density followed by further sintering at a temperature where a liquid phase is present, vacuum annealing, and cold working to achieve high uniform hardness.

Developing a vacuum thermal stripping - acid absorption process for ammonia recovery from anaerobic digester effluent.

PubMed

Ukwuani, Anayo T; Tao, Wendong

2016-12-01

To prevent acetoclastic methanogens from ammonia inhibition in anaerobic digestion of protein-rich substrates, ammonia needs to be removed or recovered from digestate. This paper presents an innovative ammonia recovery process that couples vacuum thermal stripping with acid absorption. Ammonia is stripped out of digestate boiling at a temperature below the normal boiling point due to vacuum. Stripped ammonia is absorbed to a sulfuric acid solution, forming ammonium sulfate crystals as a marketable product. Three common types of digestate were found to have boiling point temperature-vacuum curves similar to water. Seven combinations of boiling temperature and vacuum (50 °C 16.6 kPa, 58 °C 20.0 kPa, 65 °C 25.1 kPa, 70 °C 33.6 kPa, 80 °C 54.0 kPa, 90 °C 74.2 kPa, and 100 °C 101.3 kPa) were tested for batch stripping of ammonia in dairy manure digestate. 93.3-99.9% of ammonia was stripped in 3 h. The Lewis-Whitman model fitted ammonia stripping process well. Ammonia mass transfer coefficient was significantly higher at boiling temperature 65-100 °C and vacuum pressure 25.1-101.3 kPa than 50-58 °C and 16.6-20.0 kPa. The low ammonia saturation concentrations (0-24 mg N/L) suggested a large driving force to strip ammonia. The optimum boiling point temperature - vacuum pressure for ammonia recovery in a recirculation line of a mesophilic digester was 65 °C and 25.1 kPa, at which the ammonia mass transfer coefficient was as high as 37.3 mm/h. Installation of a demister and liquid trap could avoid negative effects of higher stripping temperature and stronger vacuum on formation of ammonium sulfate crystals. Pilot tests demonstrated that high-purity ammonium sulfate crystals could be produced by controlling sulfuric acid content and maintaining acid solution saturated with ammonium sulfate. Although volatile organic compounds such as cyclohexene were found in the final acid solutions, no volatile organic compounds were found in the recovered crystals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Large-capacity pump vaporizer for liquid hydrogen and nitrogen

NASA Technical Reports Server (NTRS)

Hauser, J. A.

1970-01-01

Pump vaporizer system delivers 500 standard cubic feet per minute of hydrogen or nitrogen, one system delivers both gases. Vacuum-jacketed pump discharges liquid hydrogen or liquid nitrogen into vaporizing system heated by ambient air. Principal characteristics of the flow and discharge system, pump, and vaporizer are given.

46 CFR 162.017-2 - Type.

Code of Federal Regulations, 2011 CFR

2011-10-01

... APPROVAL ENGINEERING EQUIPMENT Valves, Pressure-Vacuum Relief, for Tank Vessels § 162.017-2 Type. This specification covers the design and construction of pressure-vacuum relief valves intended for use in venting systems on all tank vessels transporting inflammable or combustible liquids. [56 FR 35827, July 29, 1991] ...

46 CFR 162.017-2 - Type.

Code of Federal Regulations, 2010 CFR

2010-10-01

... APPROVAL ENGINEERING EQUIPMENT Valves, Pressure-Vacuum Relief, for Tank Vessels § 162.017-2 Type. This specification covers the design and construction of pressure-vacuum relief valves intended for use in venting systems on all tank vessels transporting inflammable or combustible liquids. [56 FR 35827, July 29, 1991] ...

Controlled evacuation using the biocompatible and energy efficient microfluidic ejector.

PubMed

Lad, V N; Ralekar, Swati

2016-10-01

Development of controlled vacuum is having many applications in the realm of biotechnology, cell transfer, gene therapy, biomedical engineering and other engineering activities involving separation or chemical reactions. Here we show the controlled vacuum generation through a biocompatible, energy efficient, low-cost and flexible miniature device. We have designed and fabricated microfluidic devices from polydimethylsiloxane which are capable of producing vacuum at a highly controlled rate by using water as a motive fluid. Scrupulous removal of infected fluid/body fluid from the internal hemorrhage affected parts during surgical operations, gene manipulation, cell sorting, and other biomedical activities require complete isolation of the delicate cells or tissues adjacent to the targeted location. We demonstrate the potential of the miniature device to obtain controlled evacuation without the use of highly pressurized motive fluids. Water has been used as a motive liquid to eject vapor and liquid at ambient conditions through the microfluidic devices prepared using a low-cost fabrication method. The proposed miniature device may find applications in vacuum generation especially where the controlled rate of evacuation, and limited vacuum generation are of utmost importance in order to precisely protect the cells in the nearby region of the targeted evacuated area.

Heat transfer in a liquid helium cooled vacuum tube following sudden vacuum loss

NASA Astrophysics Data System (ADS)

Dhuley, R. C.; Van Sciver, S. W.

2015-12-01

Condensation of nitrogen gas rapidly flowing into a liquid helium (LHe) cooled vacuum tube is studied. This study aims to examine the heat transfer in geometries such as the superconducting RF cavity string of a particle accelerator following a sudden loss of vacuum to atmosphere. In a simplified experiment, the flow is generated by quickly venting a large reservoir of nitrogen gas to a straight long vacuum tube immersed in LHe. Normal LHe (LHe I) and superfluid He II are used in separate experiments. The rate of condensation heat transfer is determined from the temperature of the tube measured at several locations along the gas flow. Instantaneous heat deposition rates in excess of 200 kW/m2 result from condensation of the flowing gas. The gas flow is then arrested in its path to pressurize the tube to atmosphere and estimate the heat transfer rate to LHe. A steady LHe I heat load of ≈25 kW/m2 is obtained in this scenario. Observations from the He II experiment are briefly discussed. An upper bound for the LHe I heat load is derived based on the thermodynamics of phase change of nitrogen.

Liquid-phase-deposited siloxane-based capping layers for silicon solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veith-Wolf, Boris; Wang, Jianhui; Hannu-Kuure, Milja

2015-02-02

We apply non-vacuum processing to deposit dielectric capping layers on top of ultrathin atomic-layer-deposited aluminum oxide (AlO{sub x}) films, used for the rear surface passivation of high-efficiency crystalline silicon solar cells. We examine various siloxane-based liquid-phase-deposited (LPD) materials. Our optimized AlO{sub x}/LPD stacks show an excellent thermal and chemical stability against aluminum metal paste, as demonstrated by measured surface recombination velocities below 10 cm/s on 1.3 Ωcm p-type silicon wafers after firing in a belt-line furnace with screen-printed aluminum paste on top. Implementation of the optimized LPD layers into an industrial-type screen-printing solar cell process results in energy conversion efficiencies ofmore » up to 19.8% on p-type Czochralski silicon.« less

Measurements of the Temperature-Dependent Total Hemispherical Emissivity Using an Electrostatic Levitation Facility

NASA Astrophysics Data System (ADS)

Gangopadhyay, A. K.; Kelton, K. F.

2017-01-01

Among the three fundamental processes of heat transfer (conduction, convection, and radiation), radiation is the most dominant at high temperatures. The total hemispherical emissivity is an important property that determines the amount of heat loss by radiation. Unfortunately, the emissivity, especially its temperature dependence (ɛ (T)), is unknown for most materials. Here, we demonstrate the feasibility of measuring ɛ (T) using an electrostatic levitation (ESL) technique that allows such measurements to be made on levitated solid and liquid samples in a contamination-free, high-vacuum environment. The ɛ (T) for solid Ni and liquid Zr_{60}Al_{10}Cu_{18}Ni9Co3 from these measurements is consistent with the existing literature data.

Gas-liquid interface of room-temperature ionic liquids.

PubMed

Santos, Cherry S; Baldelli, Steven

2010-06-01

The organization of ions at the interface of ionic liquids and the vacuum is an ideal system to test new ideas and concepts on the interfacial chemistry of electrolyte systems in the limit of no solvent medium. Whilst electrolyte systems have numerous theoretical and experimental methods used to investigate their properties, the ionic liquids are relatively new and our understanding of the interfacial properties is just beginning to be explored. In this critical review, the gas-liquid interface is reviewed, as this interface does not depend on the preparation of another medium and thus produces a natural interface. The interface has been investigated by sum frequency generation vibrational spectroscopy and ultra-high vacuum techniques. The results provide a detailed molecular-level view of the surface composition and structure. These have been complemented by theoretical studies. The combinations of treatments on this interface are starting to provide a somewhat convergent description of how the ions are organized at this neat interface (108 references).

Vacuum-barrier window for wide-bandwidth high-power microwave transmission

DOEpatents

Caplan, M.; Shang, C.C.

1996-08-20

A vacuum output window comprises a planar dielectric material with identical systems of parallel ridges and valleys formed in opposite surfaces. The valleys in each surface neck together along parallel lines in the bulk of the dielectric. Liquid-coolant conduits are disposed linearly along such lines of necking and have water or even liquid nitrogen pumped through to remove heat. The dielectric material can be alumina, or its crystalline form, sapphire. The electric-field of a broadband incident megawatt millimeter-wave radio frequency energy is oriented perpendicular to the system of ridges and valleys. The ridges, about one wavelength tall and with a period of about one wavelength, focus the incident energy through in ribbons that squeeze between the liquid-coolant conduits without significant losses over very broad bands of the radio spectrum. In an alternative embodiment, the liquid-coolant conduits are encased in metal within the bulk of the dielectric. 4 figs.

Vacuum-barrier window for wide-bandwidth high-power microwave transmission

DOEpatents

Caplan, Malcolm; Shang, Clifford C.

1996-01-01

A vacuum output window comprises a planar dielectric material with identical systems of parallel ridges and valleys formed in opposite surfaces. The valleys in each surface neck together along parallel lines in the bulk of the dielectric. Liquid-coolant conduits are disposed linearly along such lines of necking and have water or even liquid nitrogen pumped through to remove heat. The dielectric material can be alumina, or its crystalline form, sapphire. The electric-field of a broadband incident megawatt millimeter-wave radio frequency energy is oriented perpendicular to the system of ridges and valleys. The ridges, about one wavelength tall and with a period of about one wavelength, focus the incident energy through in ribbons that squeeze between the liquid-coolant conduits without significant losses over very broad bands of the radio spectrum. In an alternative embodiment, the liquid-coolant conduits are encased in metal within the bulk of the dielectric.

Post Retort, Pre Hydro-treat Upgrading of Shale Oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, John

Various oil feedstocks, including oil from oil shale, bitumen from tar sands, heavy oil, and refin- ery streams were reacted with the alkali metals lithium or sodium in the presence of hydrogen or methane at elevated temperature and pressure in a reactor. The products were liquids with sub- stantially reduced metals, sulfur and nitrogen content. The API gravity typically increased. Sodi- um was found to be more effective than lithium in effectiveness. The solids formed when sodium was utilized contained sodium sulfide which could be regenerated electrochemically back to so- dium and a sulfur product using a "Nasicon", sodium ionmore » conducting membrane. In addition, the process was found to be effective reducing total acid number (TAN) to zero, dramatically reduc- ing the asphaltene content and vacuum residual fraction in the product liquid. The process has promise as a means of eliminating sulfur oxide and carbon monoxide emissions. The process al- so opens the possibility of eliminating the coking process from upgrading schemes and upgrad- ing without using hydrogen.« less

Vehicle-Level Oxygen/Methane Propulsion System Hotfire Testing at Thermal Vacuum Conditions

NASA Technical Reports Server (NTRS)

Morehead, Robert L.; Melcher, J. C.; Atwell, Matthew J.; Hurlbert, Eric A.; Desai, Pooja; Werlink, Rudy

2017-01-01

A prototype integrated liquid oxygen/liquid methane propulsion system was hot-fire tested at a variety of simulated altitude and thermal conditions in the NASA Glenn Research Center Plum Brook Station In-Space Propulsion Thermal Vacuum Chamber (formerly B2). This test campaign served two purposes: 1) Characterize the performance of the Plum Brook facility in vacuum accumulator mode and 2) Collect the unique data set of an integrated LOX/Methane propulsion system operating in high altitude and thermal vacuum environments (a first). Data from this propulsion system prototype could inform the design of future spacecraft in-space propulsion systems, including landers. The test vehicle for this campaign was the Integrated Cryogenic Propulsion Test Article (ICPTA), which was constructed for this project using assets from the former Morpheus Project rebuilt and outfitted with additional new hardware. The ICPTA utilizes one 2,800 lbf main engine, two 28 lbf and two 7 lbf reaction control engines mounted in two pods, four 48-inch propellant tanks (two each for liquid oxygen and liquid methane), and a cold helium system for propellant tank pressurization. Several hundred sensors on the ICPTA and many more in the test cell collected data to characterize the operation of the vehicle and facility. Multiple notable experiments were performed during this test campaign, many for the first time, including pressure-fed cryogenic reaction control system characterization over a wide range of conditions, coil-on-plug ignition system demonstration at the vehicle level, integrated main engine/RCS operation, and a non-intrusive propellant mass gauging system. The test data includes water-hammer and thermal heat leak data critical to validating models for use in future vehicle design activities. This successful test campaign demonstrated the performance of the updated Plum Brook In-Space Propulsion thermal vacuum chamber and incrementally advanced the state of LOX/Methane propulsion technology through numerous system-level and subsystem experiments.

Perspective: Chemical reactions in ionic liquids monitored through the gas (vacuum)/liquid interface.

PubMed

Maier, F; Niedermaier, I; Steinrück, H-P

2017-05-07

This perspective analyzes the potential of X-ray photoelectron spectroscopy under ultrahigh vacuum (UHV) conditions to follow chemical reactions in ionic liquids in situ. Traditionally, only reactions occurring on solid surfaces were investigated by X-ray photoelectron spectroscopy (XPS) in situ. This was due to the high vapor pressures of common liquids or solvents, which are not compatible with the required UHV conditions. It was only recently realized that the situation is very different when studying reactions in Ionic Liquids (ILs), which have an inherently low vapor pressure, and first studies have been performed within the last years. Compared to classical spectroscopy techniques used to monitor chemical reactions, the advantage of XPS is that through the analysis of their core levels all relevant elements can be quantified and their chemical state can be analyzed under well-defined (ultraclean) conditions. In this perspective, we cover six very different reactions which occur in the IL, with the IL, or at an IL/support interface, demonstrating the outstanding potential of in situ XPS to gain insights into liquid phase reactions in the near-surface region.

Derivation of Hamaker Dispersion Energy of Amorphous Carbon Surfaces in Contact with Liquids Using Photoelectron Energy-Loss Spectra

NASA Astrophysics Data System (ADS)

Godet, Christian; David, Denis

2017-12-01

Hamaker interaction energies and cutoff distances have been calculated for disordered carbon films, in contact with purely dispersive (diiodomethane) or polar (water) liquids, using their experimental dielectric functions ɛ ( q, ω) obtained over a broad energy range. In contrast with previous works, a q-averaged < ɛ ( q, ω) > q is derived from photoelectron energy-loss spectroscopy (XPS-PEELS) where the energy loss function (ELF) < Im[-1/ ɛ ( q, ω)] > q is a weighted average over allowed transferred wave vector values, q, given by the physics of bulk plasmon excitation. For microcrystalline diamond and amorphous carbon films with a wide range of (sp3/sp2 + sp3) hybridization, non-retarded Hamaker energies, A 132 ( L < 1 nm), were calculated in several configurations, and distance and wavenumber cutoff values were then calculated based on A 132 and the dispersive work of adhesion obtained from contact angles. A geometric average approximation, H 0 CVL = ( H 0 CVC H 0 LVL )1/2, holds for the cutoff separation distances obtained for carbon-vacuum-liquid (CVL), carbon-vacuum-carbon (CVC) and liquid-vacuum-liquid (LVL) equilibrium configurations. The linear dependence found for A CVL, A CLC and A CLV values as a function of A CVC, for each liquid, allows predictive relationships for Hamaker energies (in any configuration) using experimental determination of the dispersive component of the surface tension, {γ}_{CV}^d , and a guess value of the cutoff distance H 0 CVC of the solid. [Figure not available: see fulltext.

Vacuum deposition and curing of liquid monomers

DOEpatents

Affinito, J.D.

1993-11-09

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of standard polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Vacuum deposition and curing of liquid monomers

DOEpatents

Affinito, J.D.

1995-03-07

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of ``standard`` polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Vacuum deposition and curing of liquid monomers

DOEpatents

Affinito, John D.

1993-01-01

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Vacuum deposition and curing of liquid monomers apparatus

DOEpatents

Affinito, John D.

1996-01-01

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Vacuum deposition and curing of liquid monomers

DOEpatents

Affinito, John D.

1995-01-01

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Thermogravimetric determination of the coking kinetics of Arab heavy vacuum residuum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schucker, R.C.

1983-10-01

The progressively heavier nature of available feedstocks has put a premium on efficient, low-cost refinery processes to convert residuum to lighter products. One such process is fluid coking, and the present study was undertaken to provide information on the coking kinetics of Arab Heavy vacuum residuum-a feed of commercial interest. The feed was first separated by solvent deasphalting and liquid-solid absorption techniques into four fractions asphaltenes, polar aromatics, aromatics, and saturates. Each of these fractions and the whole residuum were then subjected to nonisothermal kinetic analysis using thermogravimetry. Both weight loss and its first derivative were monitored as a functionmore » of temperature at heating rates ranging from 1 degree C/min to 20 degrees C/min. Activation energies and frequency factors were obtained at various conversion levels and in all cases were shown to increase with conversion. This strongly suggests the use of an activation energy distribution for future coking kinetic modeling.« less

Lightweight Liquid Helium Dewar for High-Altitude Balloon Payloads

NASA Technical Reports Server (NTRS)

Kogut, Alan; James, Bryan; Fixsen, Dale

2013-01-01

Astrophysical observations at millimeter wavelengths require large (2-to-5- meter diameter) telescopes carried to altitudes above 35 km by scientific research balloons. The scientific performance is greatly enhanced if the telescope is cooled to temperatures below 10 K with no emissive windows between the telescope and the sky. Standard liquid helium bucket dewars can contain a suitable telescope for telescope diameter less than two meters. However, the mass of a dewar large enough to hold a 3-to-5-meter diameter telescope would exceed the balloon lift capacity. The solution is to separate the functions of cryogen storage and in-flight thermal isolation, utilizing the unique physical conditions at balloon altitudes. Conventional dewars are launched cold: the vacuum walls necessary for thermal isolation must also withstand the pressure gradient at sea level and are correspondingly thick and heavy. The pressure at 40 km is less than 0.3% of sea level: a dewar designed for use only at 40 km can use ultra thin walls to achieve significant reductions in mass. This innovation concerns new construction and operational techniques to produce a lightweight liquid helium bucket dewar. The dewar is intended for use on high-altitude balloon payloads. The mass is low enough to allow a large (3-to-5-meter) diameter dewar to fly at altitudes above 35 km on conventional scientific research balloons without exceeding the lift capability of the balloon. The lightweight dewar has thin (250- micron) stainless steel walls. The walls are too thin to support the pressure gradient at sea level: the dewar launches warm with the vacuum space vented continuously during ascent to eliminate any pressure gradient across the walls. A commercial 500-liter storage dewar maintains a reservoir of liquid helium within a minimal (hence low mass) volume. Once a 40-km altitude is reached, the valve venting the vacuum space of the bucket dewar is closed to seal the vacuum space. A vacuum pump then evacuates the dewar vacuum space to provide the necessary thermal isolation. Liquid helium may then be transferred from the storage dewar into the bucket dewar to cool the telescope inside the bucket dewar. By splitting the functions of helium storage and in-flight thermal isolation, the parasitic mass associated with the dewar pressure vessel is eliminated to achieve factor-of-five or better reduction in mass. The lower mass allows flight on conventional scientific research balloons, even for telescopes 3 to 5 meters in diameter.

Liquid gallium rotary electric contract

NASA Technical Reports Server (NTRS)

Przybyszewski, J. S.

1969-01-01

Due to its low vapor pressure, gallium, when substituted for mercury in a liquid slip ring system, transmits substantial amounts of electrical current to rotating components in an ultrahigh vacuum. It features low electrical loss, little or no wear, and long maintenance-free life.

Recovering low-turbidity cutting liquid from silicon slurry waste.

PubMed

Tsai, Tzu-Hsuan; Shih, Yu-Pei

2014-04-30

In order to recover a low-turbidity polyalkylene glycol (PAG) liquid from silicon slurry waste by sedimentation, temperatures were adjusted, and acetone, ethanol or water was used as a diluent. The experimental results show that the particles in the waste would aggregate and settle readily by using water as a diluent. This is because particle surfaces had lower surface potential value and weaker steric stabilization in PAG-water than in PAG-ethanol or PAG-acetone solutions. Therefore, water is the suggested diluent for recovering a low-turbidity PAG (<100 NTU) by sedimentation. After 50 wt.% water-assisted sedimentation for 21 days, the solid content of the upper liquid reduced to 0.122 g/L, and the turbidity decreased to 44 NTU. The obtained upper liquid was then vacuum-distillated to remove water. The final recovered PAG with 0.37 NTU had similar viscosity and density to the unused PAG and could be reused in the cutting process. Copyright © 2014 Elsevier B.V. All rights reserved.

USC/AIAA student get away special project liquid droplet collector experiment

NASA Technical Reports Server (NTRS)

Levesque, Raymond J., II

1987-01-01

This experimental payload was developed in order to observe, in a micro-gravity vacuum environment, the characteristics and stability of a thin fluid film flowing across a slightly curved surface. The test apparatus was designed based upon various ground-based thin film investigations, combined with the constraints imposed by the rigors of launch and the space environment. Testing of the fluid test article at atmospheric pressure and in vacuum verified the design provisions employed concerning ultra-low inlet pressure pump construction, as well as confirming expected pressure losses in the system. During the course of hardware development and construction modifications were required; however, the overall payload configuration remained largely unchanged. This will allow for modification and reflight of the apparatus based upon the findings of the initial flight. The specific applications of this experiment include Liquid Droplet Radiator development and various forms of material transport in vacuum.

A step towards long-wavelength protein crystallography: subjecting protein crystals to a vacuum

PubMed Central

Panjikar, Santosh; Thomsen, Lars; O’Donnell, Kane Michael; Riboldi-Tunnicliffe, Alan

2015-01-01

Using the UHV experimental endstation on the soft X-ray beamline at the Australian Synchrotron, lysozyme and proteinase K crystals have been exposed to a vacuum of 10−5 mbar, prior to flash-cooling in a bath of liquid nitrogen. Subsequent data collection on the MX2 beamline at the Australian Synchrotron demonstrated that, for lysozyme and proteinase K, it is possible to subject these mounted crystals to a vacuum pressure of 10−5 mbar without destroying the crystal lattice. Despite the lower data quality of the vacuum-pumped crystals compared with control crystals, it is demonstrated that the protein crystals can survive in a vacuum under suitable conditions. PMID:26089765

A new approach for performing contamination control bakeouts in JPL thermal vacuum test chambers

NASA Technical Reports Server (NTRS)

Johnson, Kenneth R.; Taylor, Daniel M.; Lane, Robert W.; Cortez, Maximo G.; Anderson, Mark R.

1992-01-01

Contamination control requirements for the Wide Field/Planetary Camera II (WF/PC II) are necessarily stringent to protect against post-launch contamination of the sensitive optical surfaces, particularly the cold charge coupled device (CCD) imaging surfaces. Typically, thermal vacuum test chambers have employed a liquid nitrogen (LN2) cold trap to collect outgassed contaminants. This approach has the disadvantage of risking recontamination of the test article from shroud offgassing during post-test warmup of the chamber or from any shroud warming of even a few degrees during the bakeout process. By using an enclave, essentially a chamber within a chamber, configured concentrically and internally within an LN2 shroud, a method was developed, based on a design concept by Taylor, for preventing recontamination of test articles during bakeouts and subsequent post-test warmup of the vacuum chamber. Enclaves for testing WF/PC II components were designed and fabricated, then installed in three of JPL's Environmental Test Lab chambers. The design concepts, operating procedures, and test results of this development are discussed.

An innovative intermittent-vacuum assisted thermophilic anaerobic digestion process for effective animal manure utilization and treatment.

PubMed

Zhang, Renchuan; Anderson, Erik; Addy, Min; Deng, Xiangyuan; Kabir, Fayal; Lu, Qian; Ma, Yiwei; Cheng, Yanling; Liu, Yuhuan; Chen, Paul; Ruan, Roger

2017-11-01

Intermittent-vacuum stripping (IVS) was developed as a pretreatment for thermophilic anaerobic digestion (TAD) to improve methanogenesis and hydrolysis activity through preventing free ammonia and hydrogen sulfide (H 2 S) inhibition from liquid swine manure (LSM). Over 98% of ammonia and 38% organic nitrogen were removed in 60min from 55°C to 85°C with vacuum pressure (from 100.63±3.79mmHg to 360.91±7.39mmHg) at initial pH 10.0 by IVS. Thermophilic methanogenesis and hydrolysis activity of pretreated LSM increased 52.25% (from 11.56±1.75% to 17.60±0.49%) in 25days and 40% (from 10days to 6days) in bio-methane potential assay. Over 80% H 2 S and total nitrogen were removed by IVS assistance, while around 70% nitrogen was recycled as ammonium sulfate. Therefore, IVS-TAD combination could be an effective strategy to improve TAD efficiency, whose elution is more easily utilized in algae cultivation and/or hydroponic system. Copyright © 2017 Elsevier Ltd. All rights reserved.

46 CFR 32.55-25 - Venting of cargo tanks of tank barges constructed on or after July 1, 1951-B/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... for a particular grade of liquid, the venting system permitted for a higher grade of liquid may be used instead. (b) Grade A, B, or C liquids. Cargo tanks in which Grade A, B, or C liquids are to be transported shall be fitted with either individual pressure-vacuum relief valves which shall extend to a...

46 CFR 32.55-25 - Venting of cargo tanks of tank barges constructed on or after July 1, 1951-B/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... for a particular grade of liquid, the venting system permitted for a higher grade of liquid may be used instead. (b) Grade A, B, or C liquids. Cargo tanks in which Grade A, B, or C liquids are to be transported shall be fitted with either individual pressure-vacuum relief valves which shall extend to a...

46 CFR 32.55-25 - Venting of cargo tanks of tank barges constructed on or after July 1, 1951-B/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for a particular grade of liquid, the venting system permitted for a higher grade of liquid may be used instead. (b) Grade A, B, or C liquids. Cargo tanks in which Grade A, B, or C liquids are to be transported shall be fitted with either individual pressure-vacuum relief valves which shall extend to a...

46 CFR 32.55-25 - Venting of cargo tanks of tank barges constructed on or after July 1, 1951-B/ALL.

Code of Federal Regulations, 2012 CFR

2012-10-01

... for a particular grade of liquid, the venting system permitted for a higher grade of liquid may be used instead. (b) Grade A, B, or C liquids. Cargo tanks in which Grade A, B, or C liquids are to be transported shall be fitted with either individual pressure-vacuum relief valves which shall extend to a...

46 CFR 32.55-25 - Venting of cargo tanks of tank barges constructed on or after July 1, 1951-B/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

... for a particular grade of liquid, the venting system permitted for a higher grade of liquid may be used instead. (b) Grade A, B, or C liquids. Cargo tanks in which Grade A, B, or C liquids are to be transported shall be fitted with either individual pressure-vacuum relief valves which shall extend to a...

Coil-On-Plug Ignition for Oxygen/Methane Liquid Rocket Engines in Thermal-Vacuum Environments

NASA Technical Reports Server (NTRS)

Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

2017-01-01

A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX)/liquid methane (LCH4) rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/LCH4 propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. A coil-on-plug ignition system has been developed to successfully demonstrate ignition reliability at these conditions while preventing corona discharge issues. The ICPTA uses spark plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp -2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, hot-fire testing at Plum Brook demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/LCH4 propulsion systems in future spacecraft.

Spatial Resolution in Scanning Electron Microscopy and Scanning Transmission Electron Microscopy Without a Specimen Vacuum Chamber.

PubMed

Nguyen, Kayla X; Holtz, Megan E; Richmond-Decker, Justin; Muller, David A

2016-08-01

A long-standing goal of electron microscopy has been the high-resolution characterization of specimens in their native environment. However, electron optics require high vacuum to maintain an unscattered and focused probe, a challenge for specimens requiring atmospheric or liquid environments. Here, we use an electron-transparent window at the base of a scanning electron microscope's objective lens to separate column vacuum from the specimen, enabling imaging under ambient conditions, without a specimen vacuum chamber. We demonstrate in-air imaging of specimens at nanoscale resolution using backscattered scanning electron microscopy (airSEM) and scanning transmission electron microscopy. We explore resolution and contrast using Monte Carlo simulations and analytical models. We find that nanometer-scale resolution can be obtained at gas path lengths up to 400 μm, although contrast drops with increasing gas path length. As the electron-transparent window scatters considerably more than gas at our operating conditions, we observe that the densities and thicknesses of the electron-transparent window are the dominant limiting factors for image contrast at lower operating voltages. By enabling a variety of detector configurations, the airSEM is applicable to a wide range of environmental experiments including the imaging of hydrated biological specimens and in situ chemical and electrochemical processes.

Spatial Resolution in Scanning Electron Microscopy and Scanning Transmission Electron Microscopy Without a Specimen Vacuum Chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Kayla X.; Holtz, Megan E.; Richmond-Decker, Justin

2016-07-25

Abstract A long-standing goal of electron microscopy has been the high-resolution characterization of specimens in their native environment. However, electron optics require high vacuum to maintain an unscattered and focused probe, a challenge for specimens requiring atmospheric or liquid environments. Here, we use an electron-transparent window at the base of a scanning electron microscope’s objective lens to separate column vacuum from the specimen, enabling imaging under ambient conditions, without a specimen vacuum chamber. We demonstrate in-air imaging of specimens at nanoscale resolution using backscattered scanning electron microscopy (airSEM) and scanning transmission electron microscopy. We explore resolution and contrast using Montemore » Carlo simulations and analytical models. We find that nanometer-scale resolution can be obtained at gas path lengths up to 400μm, although contrast drops with increasing gas path length. As the electron-transparent window scatters considerably more than gas at our operating conditions, we observe that the densities and thicknesses of the electron-transparent window are the dominant limiting factors for image contrast at lower operating voltages. By enabling a variety of detector configurations, the airSEM is applicable to a wide range of environmental experiments including the imaging of hydrated biological specimens andin situchemical and electrochemical processes.« less

Vacuum deposition and curing of liquid monomers apparatus

DOEpatents

Affinito, J.D.

1996-08-20

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of ``standard`` polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface. 3 figs.

Liquid-fuel valve with precise throttling control

NASA Technical Reports Server (NTRS)

Mcdougal, A. R.; Porter, R. N.; Riebling, R. W.

1971-01-01

Prototype liquid-fuel valve performs on-off and throttling functions in vacuum without component cold-welding or excessive leakage. Valve design enables simple and rapid disassembly and parts replacement and operates with short working stroke, providing maximum throttling sensitivity commensurate with good control.

The nanoaquarium: A nanofluidic platform for in situ transmission electron microscopy in liquid media

NASA Astrophysics Data System (ADS)

Grogan, Joseph M.

There are many scientifically interesting and technologically relevant nanoscale phenomena that take place in liquid media. Examples include aggregation and assembly of nanoparticles; colloidal crystal formation; liquid phase growth of structures such as nanowires; electrochemical deposition and etching for fabrication processes and battery applications; interfacial phenomena; boiling and cavitation; and biological interactions. Understanding of these fields would benefit greatly from real-time, in situ transmission electron microscope (TEM) imaging with nanoscale resolution. Most liquids cannot be imaged by traditional TEM due to evaporation in the high vacuum environment and the requirement that samples be very thin. Liquid-cell in situ TEM has emerged as an exciting new experimental technique that hermetically seals a thin slice of liquid between two electron transparent membranes to enable TEM imaging of liquid-based processes. This work presents details of the fabrication of a custom-made liquid-cell in situ TEM device, dubbed the nanoaquarium. The nanoaquarium's highlights include an exceptionally thin sample cross section (10s to 100s of nm); wafer scale processing that enables high-yield mass production; robust hermetic sealing that provides leak-free operation without use of glue, epoxy, or any polymers; compatibility with lab-on-chip technology; and on-chip integrated electrodes for sensing and actuation. The fabrication process is described, with an emphasis on direct wafer bonding. Experimental results involving direct observation of colloid aggregation using an aqueous solution of gold nanoparticles are presented. Quantitative analysis of the growth process agrees with prior results and theory, indicating that the experimental technique does not radically alter the observed phenomenon. For the first time, in situ observations of nanoparticles at a contact line and in an evaporating thin film of liquid are reported, with applications for techniques such as dip-coating and drop-casting, commonly used for depositing nanoparticles on a surface via convective-capillary assembly. Theoretical analysis suggests that the observed particle motion and aggregation are caused by gradients in surface tension and disjoining pressure in the thin liquid film.

Extending atomistic simulation timescale in solid/liquid systems: crystal growth from solution by a parallel-replica dynamics and continuum hybrid method.

PubMed

Lu, Chun-Yaung; Voter, Arthur F; Perez, Danny

2014-01-28

Deposition of solid material from solution is ubiquitous in nature. However, due to the inherent complexity of such systems, this process is comparatively much less understood than deposition from a gas or vacuum. Further, the accurate atomistic modeling of such systems is computationally expensive, therefore leaving many intriguing long-timescale phenomena out of reach. We present an atomistic/continuum hybrid method for extending the simulation timescales of dynamics at solid/liquid interfaces. We demonstrate the method by simulating the deposition of Ag on Ag (001) from solution with a significant speedup over standard MD. The results reveal specific features of diffusive deposition dynamics, such as a dramatic increase in the roughness of the film.

Simple synthetic route for hydroxyapatite colloidal nanoparticles via a Nd:YAG laser ablation in liquid medium

NASA Astrophysics Data System (ADS)

Mhin, Sung Wook; Ryu, Jeong Ho; Kim, Kang Min; Park, Gyeong Seon; Ryu, Han Wool; Shim, Kwang Bo; Sasaki, Takeshi; Koshizaki, Naoto

2009-08-01

Pulsed laser ablation (PLA) in liquid medium was successfully employed to synthesize hydroxyapatite (HAp) colloidal nanoparticles. The crystalline phase, particle morphology, size distribution and microstructure of the HAp nanoparticles were investigated in detail. The obtained HAp nanoparticles had spherical shape with sizes ranging from 5 to 20 nm. The laser ablation and the nanoparticle forming process were studied in terms of the explosive ejection mechanism by investigating the change of the surface morphology on target. The stoichiometry and bonding properties were studied by using XPS, FT-IR and Raman spectroscopy. A molar ratio of Ca/P of the prepared HAp nanoparticles was more stoichiometric than the value reported in the case of ablation in vacuum.

Simplified Methodology to Estimate the Maximum Liquid Helium (LHe) Cryostat Pressure from a Vacuum Jacket Failure

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.; Richards, W. Lance

2015-01-01

The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared astronomical observation experiments. These experiments carry sensors cooled to liquid helium temperatures. The liquid helium supply is contained in large (i.e., 10 liters or more) vacuum-insulated dewars. Should the dewar vacuum insulation fail, the inrushing air will condense and freeze on the dewar wall, resulting in a large heat flux on the dewar's contents. The heat flux results in a rise in pressure and the actuation of the dewar pressure relief system. A previous NASA Engineering and Safety Center (NESC) assessment provided recommendations for the wall heat flux that would be expected from a loss of vacuum and detailed an appropriate method to use in calculating the maximum pressure that would occur in a loss of vacuum event. This method involved building a detailed supercritical helium compressible flow thermal/fluid model of the vent stack and exercising the model over the appropriate range of parameters. The experimenters designing science instruments for SOFIA are not experts in compressible supercritical flows and do not generally have access to the thermal/fluid modeling packages that are required to build detailed models of the vent stacks. Therefore, the SOFIA Program engaged the NESC to develop a simplified methodology to estimate the maximum pressure in a liquid helium dewar after the loss of vacuum insulation. The method would allow the university-based science instrument development teams to conservatively determine the cryostat's vent neck sizing during preliminary design of new SOFIA Science Instruments. This report details the development of the simplified method, the method itself, and the limits of its applicability. The simplified methodology provides an estimate of the dewar pressure after a loss of vacuum insulation that can be used for the initial design of the liquid helium dewar vent stacks. However, since it is not an exact tool, final verification of the dewar pressure vessel design requires a complete, detailed real fluid compressible flow model of the vent stack. The wall heat flux resulting from a loss of vacuum insulation increases the dewar pressure, which actuates the pressure relief mechanism and results in high-speed flow through the dewar vent stack. At high pressures, the flow can be choked at the vent stack inlet, at the exit, or at an intermediate transition or restriction. During previous SOFIA analyses, it was observed that there was generally a readily identifiable section of the vent stack that would limit the flow – e.g., a small diameter entrance or an orifice. It was also found that when the supercritical helium was approximated as an ideal gas at the dewar condition, the calculated mass flow rate based on choking at the limiting entrance or transition was less than the mass flow rate calculated using the detailed real fluid model2. Using this lower mass flow rate would yield a conservative prediction of the dewar’s wall heat flux capability. The simplified method of the current work was developed by building on this observation.

Unique orientations and rotational dynamics of a 1-butyl-3-methyl-imidazolium hexafluorophosphate ionic liquid at the gas-liquid interface: the effects of the hydrogen bond and hydrophobic interactions.

PubMed

Yang, Deshuai; Fu, Fangjia; Li, Li; Yang, Zhen; Wan, Zheng; Luo, Yi; Hu, Na; Chen, Xiangshu; Zeng, Guixiang

2018-05-07

Here we report a series of molecular dynamics simulations for the orientations and rotational dynamics of the 1-butyl-3-methyl-imidazoliumhexafluorophosphate ([BMIM][PF 6 ]) ionic liquid (IL) at the gas-liquid interface. Compared to the bulk phase, the [BMIM] + cations at the interface prefer to orientate themselves with their imidazolium rings perpendicular to the gas-IL interface plane and their butyl chains pointing toward the vacuum phase. Such a preferential orientation can be attributed to the combined effect of the hydrophobic interactions and the optimum loss of hydrogen bonds (HBs). More interestingly, our simulation results demonstrate that the butyl chains of cations exhibit a two-stage rotational behavior at the interface, where the butyl chains are always in the vacuum phase at the first stage and the second stage corresponds to the butyl chains migrating from the vacuum phase into the liquid phase. A further detailed analysis reveals that their rotational motions at the first stage are mainly determined by the weakened HB strength at the interface while those at the second stage are dominated by their hydrophobic interactions. Such a unique rotational behavior of the butyl chains is significantly different from those of the anions and the imidazolium rings of cations at the interface due to the lack of existence of hydrophobic interaction in the cases of the latter two. In addition, a new and simple time correlation function (TCF) was constructed here for the first time to quantitatively identify the relevant hydrophobic interaction of alkyl chains. Therefore, our simulation results provide a molecular-level understanding of the effects of HB and hydrophobic interactions on the unique properties of imidazolium-based ILs at the gas-liquid interface.

Studying dynamic processes in liquids by TEM/STEM/DTEM

NASA Astrophysics Data System (ADS)

Abellan, Patricia; Evans, James; Woehl, Taylor; Jungjohann, Katherine; Parent, Lucas; Arslan, Ilke; Ristenpart, William; Browning, Nigel; Mater. Sci. Group Team; Microsc. Group Team; Catal. Sci. Group Collaboration; Ristenpart Res. Group Collaboration

2013-03-01

In order to study dynamic phenomena such as corrosion or catalysis, extreme environmental conditions must be reproduced around the specimen - these include high-temperatures, high-pressures, specific oxidizing/reducing atmospheres or a liquid environment. The use of environmental stages specifically designed to fit in any transmission electron microscope (TEM) allows us to apply the distinct capabilities of each instrument to study dynamic processes. Localized gas/fluid conditions are created around the sample and separated from the high vacuum inside the microscope using hermetically sealed windowed-cells. Advanced capabilities of these techniques include spatial resolutions of ~1 Angstrom or better in aberration corrected instruments or temporal resolutions in the microsecond-nanosecond range in a dynamic TEM (DTEM). Here, unique qualities of the DTEM that benefit the in-situ experiments with gas/fluid environmental cells will be discussed. We also present our results with a liquid stage allowing atomic resolution imaging of nanomaterials in a colloidal suspension, core EEL spectra acquisition, continuous flow, controlled growth of nanocrystals and systematic calibration of the effect of the electron dose on silver nuclei formation.

Cavity optomechanics in a levitated helium drop

NASA Astrophysics Data System (ADS)

Childress, L.; Schmidt, M. P.; Kashkanova, A. D.; Brown, C. D.; Harris, G. I.; Aiello, A.; Marquardt, F.; Harris, J. G. E.

2017-12-01

We describe a proposal for a type of optomechanical system based on a drop of liquid helium that is magnetically levitated in vacuum. In the proposed device, the drop would serve three roles: its optical whispering-gallery modes would provide the optical cavity, its surface vibrations would constitute the mechanical element, and evaporation of He atoms from its surface would provide continuous refrigeration. We analyze the feasibility of such a system in light of previous experimental demonstrations of its essential components: magnetic levitation of mm-scale and cm-scale drops of liquid He , evaporative cooling of He droplets in vacuum, and coupling to high-quality optical whispering-gallery modes in a wide range of liquids. We find that the combination of these features could result in a device that approaches the single-photon strong-coupling regime, due to the high optical quality factors attainable at low temperatures. Moreover, the system offers a unique opportunity to use optical techniques to study the motion of a superfluid that is freely levitating in vacuum (in the case of 4He). Alternatively, for a normal fluid drop of 3He, we propose to exploit the coupling between the drop's rotations and vibrations to perform quantum nondemolition measurements of angular momentum.

Production of needle-type liquid-metal ion sources and their application in a scanning ion muscope

NASA Astrophysics Data System (ADS)

Knapp, Helmut; Rübesame, Detlef; Niedrig, Heinz

1991-07-01

A tungsten wire is electrochemically etched in NaOH to produce tip radii of 4-10 μm for use in liquid-metal ion sources (LMIS). To ensure complete wetting of the needle with the liquid metal (Sn, Ga), the needle has to be annealed at 800-1000°C by electron bombardment in a vacuum. It is then immediately dipped into the liquid metal in the same vacuum chamber. An anode prepared in this way is part of a triode system, followed by an octupole stigmator, an electrostatic einzel lens and the scanning unit. Upon application of a high voltage the liquid metal will form a Taylor cone at the needle tip. In the resulting high electrical field ions are extracted through field evaporation. Typical beam current and spot size values during scanning ion muscope (SIM) operation are 2.5 μA and 10 μm respectively. An Everhart-Thornley detector and a quadrupole mass spectrometer are available to allow analysis of secondary particles emitted from the target.

Vacuum decay container/closure integrity testing technology. Part 1. ASTM F2338-09 precision and bias studies.

PubMed

Wolf, Heinz; Stauffer, Tony; Chen, Shu-Chen Y; Lee, Yoojin; Forster, Ronald; Ludzinski, Miron; Kamat, Madhav; Godorov, Phillip; Guazzo, Dana Morton

2009-01-01

ASTM F2338-09 Standard Test Method for Nondestructive Detection of Leaks in Packages by Vacuum Decay Method is applicable for leak-testing rigid and semi-rigid non-lidded trays; trays or cups sealed with porous barrier lidding materials; rigid, nonporous packages; and flexible, nonporous packages. Part 1 of this series describes the precision and bias studies performed in 2008 to expand this method's scope to include rigid, nonporous packages completely or partially filled with liquid. Round robin tests using three VeriPac 325/LV vacuum decay leak testers (Packaging Technologies & Inspection, LLC, Tuckahoe, NY) were performed at three test sites. Test packages were 1-mL glass syringes. Positive controls had laser-drilled holes in the barrel ranging from about 5 to 15 microm in nominal diameter. Two different leak tests methods were performed at each site: a "gas leak test" performed at 250 mbar (absolute) and a "liquid leak test" performed at about 1 mbar (absolute). The gas leak test was used to test empty, air-filled syringes. All defects with holes > or = 5.0 microm and all no-defect controls were correctly identified. The only false negative result was attributed to a single syringe with a < 5.0-microm hole. Tests performed using a calibrated air leak supported a 0.10-cm3 x min(-1) (ccm) sensitivity limit (99/99 lower tolerance limit). The liquid leak test was used to test both empty, air-filled syringes and water-filled syringes. Test results were 100% accurate for all empty and water-filled syringes, both without holes and with holes (5, 10, and 15 microm). Tests performed using calibrated air flow leaks of 0, 0.05, and 0.10 ccm were also 100% accurate; data supported a 0.10-ccm sensitivity limit (99/99 lower tolerance limit). Quantitative differential pressure results strongly correlated to hole size using either liquid or gas vacuum decay leak tests. The higher vacuum liquid leak test gave noticeably higher pressure readings when water was present in the defect. Both the ASTM F2338-09 test method and the precision and bias study report are available by contacting ASTM International in West Conshohocken, PA, USA (www.astm.org).

Drift study of SU8 cantilevers in liquid and gaseous environments.

PubMed

Tenje, Maria; Keller, Stephan; Dohn, Søren; Davis, Zachary J; Boisen, Anja

2010-05-01

We present a study of the drift, in terms of cantilever deflections without probe/target interactions, of polymeric SU8 cantilevers. The drift is measured in PBS buffer (pH 7.4) and under vacuum (1mbar) conditions. We see that the cantilevers display a large drift in both environments. We believe this is because the polymer matrix absorbs liquid in one situation whereas it is being degassed in the other. An inhomogeneous expansion/contraction of the cantilever is seen because one surface of the cantilever may still have remains of the release layer from the fabrication. To further study the effect, we coat the cantilevers with a hydrophobic coating, perfluorodecyltrichlorosilane (FDTS). Fully encapsulating the SU8 cantilever greatly reduces the drift in liquid whereas a less significant change is seen in vacuum.

Gas propagation following a sudden loss of vacuum in a pipe cooled by He I and He II.

NASA Astrophysics Data System (ADS)

Garceau, N.; Guo, W.; Dodamead, T.

2017-12-01

Many cryogenic systems around the world are concerned with the sudden catastrophic loss of vacuum for cost, preventative damage, safety or other reasons. The experiments in this paper were designed to simulate the sudden vacuum break in the beam-line pipe of a liquid helium cooled superconducting particle accelerator. This paper expands previous research conducted at the National High Magnetic Field Laboratory and evaluates the differences between normal helium (He I) and superfluid helium (He II). For the experiments, a straight pipe and was evacuated and immersed in liquid helium at 4.2 K and below 2.17 K. Vacuum loss was simulated by opening a solenoid valve on a buffer tank filled nitrogen gas. Gas front arrival was observed by a temperature rise of the tube. Preliminary results suggested that the speed of the gas front through the experiment decreased exponentially along the tube for both normal liquid helium and super-fluid helium. The system was modified to a helical pipe system to increase propagation length. Testing and analysis on these two systems revealed there was minor difference between He I and He II despite the difference between the two distinct helium phases heat transfer mechanisms: convection vs thermal counterflow. Furthermore, the results indicated that the temperature of the tube wall above the LHe bath also plays a significant role in the initial front propagation. More systematic measurements are planned in with the helical tube system to further verify the results.

Research on Melt Degassing Processes of High Conductivity Hard Drawn Aluminum Wire

NASA Astrophysics Data System (ADS)

Xu, Xuexia; Feng, Yanting; Wang, Qing; Li, Wenbin; Fan, Hui; Wang, Yong; Li, Guowei; Zhang, Daoqian

2018-03-01

Degassing effects of ultrasonic and vacuum processes on high conductivity hard drawn aluminum melt were studied. Results showed that the degassing efficiency improved with the increase of ultrasonic power within certain range, stabilizing at 70% with 240W. For vacuum degassing process, hydrogen content of aluminum melt decreased with the loading time and was linear with logarithm of vacuum degree. Comparison of degassing effects of ultrasonic, vacuum, vacuum-ultrasonic degassing process showed that vacuum-ultrasonic process presented optimal effect.

Numerical Modeling of Thermofluid Transients During Chilldown of Cryogenic Transfer Lines

NASA Technical Reports Server (NTRS)

Majumdar, Alok; Steadman, Todd

2003-01-01

The chilldown of fluid transfer lines is an important part of using cryogenic systems such as those found in both ground and space based applications. The chilldown process is a complex combination of both thermal and fluid transient phenomena. A cryogenic liquid flows through a transfer line that is initially at a much higher temperature than the cryogen. Transient heat transfer processes between the liquid and transfer line cause vaporization of the liquid, and this phase change can cause transient pressure and flow surges in the liquid. As the transfer line is cooled, these effects diminish until the liquid reaches a steady flow condition in the chilled transfer line. If these transient phenomena are not properly accounted for in the design process of a cryogenic system, it can lead to damage or failure of system components during operation. For such cases, analytical modeling is desirable for ensuring that a cryogenic system transfer line design is adequate for handling the effects of a chilldown process. The purpose of this paper is to present the results of a numerical model developed using Generalized Fluid System Simulation Program (GFSSP)'s new fluid transient capability in combination with its previously developed thermal transient capability to predict pressure and flow surge in cryogenic transfer lines during a chilldown process. An experiment performed by the National Bureau of Standards (NBS) in 1966 has been chosen as the baseline comparison case for this work. NBS s experimental set-up consisted of a 10.59 cubic foot supply dewar, an inlet valve, and a 200 foot long, in Outside Diameter (OD) vacuum jacketed copper transfer line that exhausted to atmosphere. Three different inlet valves, an in-port ball valve, a 1-in-port globe valve and a 1-in-port gate valve, were used in NBS's experiments. Experiments were performed using both liquid hydrogen and liquid nitrogen as the fluids. The proposed paper will include detailed comparisons of GFSSP's predictions with NBS's experimental results.

Dual analyzer system for surface analysis dedicated for angle-resolved photoelectron spectroscopy at liquid surfaces and interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niedermaier, Inga; Kolbeck, Claudia; Steinrück, Hans-Peter

The investigation of liquid surfaces and interfaces with the powerful toolbox of ultra-high vacuum (UHV)-based surface science techniques generally has to overcome the issue of liquid evaporation within the vacuum system. In the last decade, however, new classes of liquids with negligible vapor pressure at room temperature—in particular, ionic liquids (ILs)—have emerged for surface science studies. It has been demonstrated that particularly angle-resolved X-ray Photoelectron Spectroscopy (ARXPS) allows for investigating phenomena that occur at gas-liquid and liquid-solid interfaces on the molecular level. The results are not only relevant for IL systems but also for liquids in general. In all ofmore » these previous ARXPS studies, the sample holder had to be tilted in order to change the polar detection angle of emitted photoelectrons, which restricted the liquid systems to very thin viscous IL films coating a flat solid support. We now report on the concept and realization of a new and unique laboratory “Dual Analyzer System for Surface Analysis (DASSA)” which enables fast ARXPS, UV photoelectron spectroscopy, imaging XPS, and low-energy ion scattering at the horizontal surface plane of macroscopically thick non-volatile liquid samples. It comprises a UHV chamber equipped with two electron analyzers mounted for simultaneous measurements in 0° and 80° emission relative to the surface normal. The performance of DASSA on a first macroscopic liquid system will be demonstrated.« less

Thermodynamic performance of multi-stage gradational lead screw vacuum pump

NASA Astrophysics Data System (ADS)

Zhao, Fan; Zhang, Shiwei; Sun, Kun; Zhang, Zhijun

2018-02-01

As a kind of dry mechanical vacuum pump, the twin-screw vacuum pump has an outstanding pumping performance during operation, widely used in the semiconductor industry. Compared with the constant lead screw (CLS) vacuum pump, the gradational lead screw (GLS) vacuum pump is more popularly applied in recent years. Nevertheless, not many comparative studies on the thermodynamic performance of GLS vacuum pump can be found in the literature. Our study focuses on one type of GLS vacuum pump, the multi-stage gradational lead screw (MGLS) vacuum pump, gives a detailed description of its construction and illustrates it with the drawing. Based on the structural analysis, the thermodynamic procedure is divided into four distinctive processes, including sucking process, transferring (compressing) process, backlashing process and exhausting process. The internal mechanism of each process is qualitatively illustrated and the mathematical expressions of seven thermodynamic parameters are given under the ideal situation. The performance curves of MGLS vacuum pump are plotted by MATLAB software and compared with those of the CLS vacuum pump in the same case. The results can well explain why the MGLS vacuum pump has more favorable pumping performance than the CLS vacuum pump in saving energy, reducing noise and heat dissipation.

Thermal Performance of Biological Substance Systems in Vitro Under Static and Dynamic Conditions at the Cryogenic Test Laboratory, NASA Kennedy Space Center, USA

NASA Technical Reports Server (NTRS)

Augustynowicz, S. D.; Fesmire, James E.; Steinrock, T. (Technical Monitor)

2001-01-01

A unique research program, including a comprehensive study of thermal performance at cryogenic vacuum insulation systems, was performed at the NASA Kennedy Space Center. The main goal was to develop a new soft vacuum system (from 1 torr to 10 torr) that provides an intermediate level of performance (k-value below 4.8 mW/m-K). Liquid nitrogen boil-off methods were used to test conventional materials, novel materials, and certain combinations. The test articles included combinations of aluminum foil, fiberglass paper, polyester fabric, silica aerogel composite blanket, fumed silica, silica aerogel powder, and syntactic foam. A new LCI system was developed at the Cryogenics Test Laboratory. This system performs exceptionally well at soft vacuum levels and nearly as good as an MLI at high vacuum levels. Apparent thermal conductivities for the LCI range from 2 mW/m-K at soft vacuum to 0.1 mW/m-K at high vacuum. Several cryostats were designed, constructed, and calibrated by the Cryogenics Test Laboratory at KSC NASA as part of this research program. The cryostat test apparatus is a liquid nitrogen boil-off calorimeter system for direct measurement of the apparent thermal conductivity at a fixed vacuum level between 5 x 10(exp -5) and 760 torr. The apparatus is also used for transient measurements of temperature profiles. The development of efficient, robust cryogenic insulation systems has been a targeted area of research for a number of years. Improved methods of characterization, testing, and evaluation of complex biological substance systems for cryosurgery and cryobiology are the focus of this paper.

Simplified installation of thrust bearings

NASA Technical Reports Server (NTRS)

Sensenbaugh, N. D.

1980-01-01

Special handling sleeve, key to method of installing thrust bearings, was developed for assembling bearings on shaft of low-pressure oxygen turbo-pump. Method eliminates cooling and vacuum-drying steps which saves time, while also eliminating possibility of corrosion formation. Procedure saves energy because it requires no liquid nitrogen for cooling shaft and no natural gas or electric power for operating vacuum oven.

Multipurpose Thermal Insulation Test Apparatus

NASA Technical Reports Server (NTRS)

Fesmire, James E. (Inventor); Augustynowicz, Stanislaw D. (Inventor)

2002-01-01

A multi-purpose thermal insulation test apparatus is used for testing insulation materials, or other components. The test apparatus is a fluid boil-off calorimeter system for calibrated measurement of the apparent thermal conductivity (k-value) of a specimen material at a fixed vacuum level. The apparatus includes an inner vessel for receiving a fluid with a normal boiling point below ambient temperature, such as liquid nitrogen, enclosed within a vacuum chamber. A cold mass assembly, including the inner vessel and thermal guards, is suspended from the top of the vacuum chamber. Handling tools attach to the cold mass assembly for convenient manipulation of the assembly and for the installation or wrapping of insulation test materials. Liquid nitrogen is typically supplied to the inner vessel using a fill tube with funnel. A single port through the top of the vacuum chamber facilitates both filling and venting. Aerogel composite stacks with reflective films are fastened to the top and the bottom of the inner vessel as thermal guards. The comparative k-value of the insulation material is determined by measuring the boil-off flow rate of gas, the temperature differential across the insulation thickness, and the dimensions (length and diameters) of the test specimen.

Critically safe volume vacuum pickup for use in wet or dry cleanup of radioactive enclosures

DOEpatents

Zeren, J.D.

1993-12-28

A physical compact vacuum pickup device of critically safe volume and geometric shape is provided for use in radioactive enclosures, such as a small glove box, to facilitate manual cleanup of either wet or dry radioactive material. The device is constructed and arranged so as to remain safe when filled to capacity with plutonium-239 oxide. Two fine mesh filter bags are supported on the exterior of a rigid fine mesh stainless steel cup. This assembly is sealed within, and spaced from, the interior walls of a stainless steel canister. An air inlet communicates with the interior of the canister. A modified conventional vacuum head is physically connected to, and associated with, the interior of the mesh cup. The volume of the canister, as defined by the space between the mesh cup and the interior walls of the canister, forms a critically safe volume and geometric shape for dry radioactive particles that are gathered within the canister. A critically safe liquid volume is maintained by operation of a suction terminating float valve, and/or by operation of redundant vacuum check/liquid drain valves and placement of the air inlet. 5 figures.

Critically safe volume vacuum pickup for use in wet or dry cleanup of radioactive enclosures

DOEpatents

Zeren, Joseph D.

1993-12-28

A physical compact vacuum pickup device of critically safe volume and geometric shape is provided for use in radioactive enclosures, such as a small glove box, to facilitate manual cleanup of either wet or dry radioactive material. The device is constructed and arranged so as to remain safe when filled to capacity with plutonium-239 oxide. Two fine mesh filter bags are supported on the exterior of a rigid fine mesh stainless steel cup. This assembly is sealed within, and spaced from, the interior walls of a stainless steel canister. An air inlet communicates with the interior of the canister. A modified conventional vacuum head is physically connected to, and associated with, the interior of the mesh cup. The volume of the canister, as defined by the space between the mesh cup and the interior walls of the canister, forms a critically safe volume and geometric shape for dry radioactive particles that are gathered within the canister. A critically safe liquid volume is maintained by operation of a suction terminating float valve, and/or by operation of redundant vacuum check/liquid drain valves and placement of the air inlet.

NASA Plum Brook's B-2 Test Facility: Thermal Vacuum and Propellant Test Facility

NASA Technical Reports Server (NTRS)

Kudlac, Maureen T.; Weaver, Harold F.; Cmar, Mark D.

2012-01-01

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) Plum Brook Station (PBS) Spacecraft Propulsion Research Facility, commonly referred to as B-2, is NASA's third largest thermal vacuum facility. It is the largest designed to store and transfer large quantities of liquid hydrogen and liquid oxygen, and is perfectly suited to support developmental testing of upper stage chemical propulsion systems as well as fully integrated stages. The facility is also capable of providing thermal-vacuum simulation services to support testing of large lightweight structures, Cryogenic Fluid Management (CFM) systems, electric propulsion test programs, and other In-Space propulsion programs. A recently completed integrated system test demonstrated the refurbished thermal vacuum capabilities of the facility. The test used the modernized data acquisition and control system to monitor the facility. The heat sink provided a uniform temperature environment of approximately 77 K. The modernized infrared lamp array produced a nominal heat flux of 1.4 kW/sq m. With the lamp array and heat sink operating simultaneously, the thermal systems produced a heat flux pattern simulating radiation to space on one surface and solar exposure on the other surface.

Fluorophore-based sensor for oxygen radicals in processing plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhury, Faraz A.; Shohet, J. Leon, E-mail: shohet@engr.wisc.edu; Sabat, Grzegorz

2015-11-15

A high concentration of radicals is present in many processing plasmas, which affects the processing conditions and the properties of materials exposed to the plasma. Determining the types and concentrations of free radicals present in the plasma is critical in order to determine their effects on the materials being processed. Current methods for detecting free radicals in a plasma require multiple expensive and bulky instruments, complex setups, and often, modifications to the plasma reactor. This work presents a simple technique that detects reactive-oxygen radicals incident on a surface from a plasma. The measurements are made using a fluorophore dye thatmore » is commonly used in biological and cellular systems for assay labeling in liquids. Using fluorometric analysis, it was found that the fluorophore reacts with oxygen radicals incident from the plasma, which is indicated by degradation of its fluorescence. As plasma power was increased, the quenching of the fluorescence significantly increased. Both immobilized and nonimmobilized fluorophore dyes were used and the results indicate that both states function effectively under vacuum conditions. The reaction mechanism is very similar to that of the liquid dye.« less

An Efficient, Versatile, and Safe Access to Supported Metallic Nanoparticles on Porous Silicon with Ionic Liquids.

PubMed

Darwich, Walid; Haumesser, Paul-Henri; Santini, Catherine C; Gaillard, Frédéric

2016-06-03

The metallization of porous silicon (PSi) is generally realized through physical vapor deposition (PVD) or electrochemical processes using aqueous solutions. The former uses a strong vacuum and does not allow for a conformal deposition into the pores. In the latter, the water used as solvent causes oxidation of the silicon during the reduction of the salt precursors. Moreover, as PSi is hydrophobic, the metal penetration into the pores is restricted to the near-surface region. Using a solution of organometallic (OM) precursors in ionic liquid (IL), we have developed an easy and efficient way to fully metallize the pores throughout the several-µm-thick porous Si. This process affords supported metallic nanoparticles characterized by a narrow size distribution. This process is demonstrated for different metals (Pt, Pd, Cu, and Ru) and can probably be extended to other metals. Moreover, as no reducing agent is necessary (the decomposition in an argon atmosphere at 50 °C is fostered by surface silicon hydride groups borne by PSi), the safety and the cost of the process are improved.

An Efficient, Versatile, and Safe Access to Supported Metallic Nanoparticles on Porous Silicon with Ionic Liquids

PubMed Central

Darwich, Walid; Haumesser, Paul-Henri; Santini, Catherine C.; Gaillard, Frédéric

2016-01-01

The metallization of porous silicon (PSi) is generally realized through physical vapor deposition (PVD) or electrochemical processes using aqueous solutions. The former uses a strong vacuum and does not allow for a conformal deposition into the pores. In the latter, the water used as solvent causes oxidation of the silicon during the reduction of the salt precursors. Moreover, as PSi is hydrophobic, the metal penetration into the pores is restricted to the near-surface region. Using a solution of organometallic (OM) precursors in ionic liquid (IL), we have developed an easy and efficient way to fully metallize the pores throughout the several-µm-thick porous Si. This process affords supported metallic nanoparticles characterized by a narrow size distribution. This process is demonstrated for different metals (Pt, Pd, Cu, and Ru) and can probably be extended to other metals. Moreover, as no reducing agent is necessary (the decomposition in an argon atmosphere at 50 °C is fostered by surface silicon hydride groups borne by PSi), the safety and the cost of the process are improved. PMID:27271608

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeishi, T.; Kotoh, K.; Kawabata, Y.

The existence of tritium-contaminated oils from vacuum pumps used in tritium facilities, is becoming an important issue since there is no disposal way for tritiated waste oils. On recovery of tritiated water vapor in gas streams, it is well-known that the isotope exchange reaction between the gas phase and the liquid phase occurs effectively at room temperature. We have carried out experiments using bubbles to examine the tritium contamination and decontamination of a volume of rotary-vacuum-pump oil. The contamination of the pump oil was made by bubbling tritiated water vapor and tritiated hydrogen gas into the oil. Subsequently the decontaminationmore » was processed by bubbling pure water vapor and dry argon gas into the tritiated oil. Results show that the water vapor bubbling was more effective than dry argon gas. The experiment also shows that the water vapor bubbling in an oil bottle can remove and transfer tritium efficiently from the tritiated oil into another water-bubbling bottle.« less

Long-Term Cryogenic Propellant Storage on Mars with Hercules Propellant Storage Facility

NASA Technical Reports Server (NTRS)

Liu, Gavin

2017-01-01

This report details the process and results of roughly sizing the steady state, zero boil-off thermal and power parameters of the Hercules Propellant Storage Facility. For power analysis, isothermal and isobaric common bulkhead tank scenarios are considered. An estimated minimum power requirement of 8.3 kW for the Reverse Turbo-Brayton Cryocooler is calculated. Heat rejection concerns in soft vacuum Mars atmosphere are noted and potential solutions are proposed. Choice of coolant for liquid propellant conditioning and issues with current proposed cryocooler cycle are addressed; recommendations are made, e.g. adding a Joule-Thomson expansion valve after the Reverse Turbo-Brayton turbine in order to have two-phase, isothermal heat exchange through the Broad Area Cooling system. Issues with cross-country transfer lines from propellant storage to flight vehicle are briefly discussed: traditional vacuum jacketed lines are implausible, and Mars insulation needs to be developed.

Design and Operation of Equipment to Detect and Remove Water within Used Nuclear Fuel Storage Bottles

DOE Office of Scientific and Technical Information (OSTI.GOV)

C.C. Baker; T.M. Pfeiffer; J.C. Price

2013-09-01

Inspection and drying equipment has been implemented in a hot cell to address the inadvertent ingress of water into used nuclear fuel storage bottles. Operated with telemanipulators, the system holds up to two fuel bottles and allows their threaded openings to be connected to pressure transducers and a vacuum pump. A prescribed pressure rebound test is used to diagnose the presence of moisture. Bottles found to contain moisture are dried by vaporization. The drying process is accelerated by the application of heat and vacuum. These techniques detect and remove virtually all free water (even water contained in a debris bed)more » while leaving behind most, if not all, particulates. The extracted water vapour passes through a thermoelectric cooler where it is condensed back to the liquid phase for collection. Fuel bottles are verified to be dry by passing the pressure rebound test.« less

Vacuum brazing of high volume fraction SiC particles reinforced aluminum matrix composites

NASA Astrophysics Data System (ADS)

Cheng, Dongfeng; Niu, Jitai; Gao, Zeng; Wang, Peng

2015-03-01

This experiment chooses A356 aluminum matrix composites containing 55% SiC particle reinforcing phase as the parent metal and Al-Si-Cu-Zn-Ni alloy metal as the filler metal. The brazing process is carried out in vacuum brazing furnace at the temperature of 550°C and 560°C for 3 min, respectively. The interfacial microstructures and fracture surfaces are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy spectrum analysis (EDS). The result shows that adequacy of element diffusion are superior when brazing at 560°C, because of higher activity and liquidity. Dislocations and twins are observed at the interface between filler and composite due to the different expansion coefficient of the aluminum alloy matrix and SiC particles. The fracture analysis shows that the brittle fracture mainly located at interface of filler and composites.

OTEC gas desorption studies

NASA Astrophysics Data System (ADS)

Chen, F. C.; Golshani, A.

1982-02-01

Experiments on deaeration in packed columns and barometric intake systems, and with hydraulic air compression for open-cycle OTEC systems are reported. A gas desorption test loop consisting of water storage tanks, a vacuum system, a liquid recirculating system, an air supply, a column test section, and two barometric leg test sections was used to perform the tests. The aerated water was directed through columns filled with either ceramic Raschig rings or plastic pall rings, and the system vacuum pressure, which drives the deaeration process, was found to be dependent on water velocity and intake pipe height. The addition of a barometric intake pipe increased the deaeration effect 10%, and further tests were run with lengths of PVC pipe as potential means for noncondensibles disposal through hydraulic air compression. Using the kinetic energy from the effluent flow to condense steam in the noncondensible stream improved the system efficiency.

Direct Analysis of Organic Compounds in Liquid Using a Miniature Photoionization Ion Trap Mass Spectrometer with Pulsed Carrier-Gas Capillary Inlet.

PubMed

Lu, Xinqiong; Yu, Quan; Zhang, Qian; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

2017-08-01

A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity. A limit of detection of 2 ppb could be achieved for 2,4-dimethylaniline in a methanol solution. The sampling system described in the present study is specifically suitable for a miniature photoionization ion trap mass spectrometer that can perform rapid and online analysis for liquid samples. Graphical Abstract ᅟ.

Direct Analysis of Organic Compounds in Liquid Using a Miniature Photoionization Ion Trap Mass Spectrometer with Pulsed Carrier-Gas Capillary Inlet

NASA Astrophysics Data System (ADS)

Lu, Xinqiong; Yu, Quan; Zhang, Qian; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

2017-08-01

A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity. A limit of detection of 2 ppb could be achieved for 2,4-dimethylaniline in a methanol solution. The sampling system described in the present study is specifically suitable for a miniature photoionization ion trap mass spectrometer that can perform rapid and online analysis for liquid samples.

Solar steam generation by heat localization.

PubMed

Ghasemi, Hadi; Ni, George; Marconnet, Amy Marie; Loomis, James; Yerci, Selcuk; Miljkovic, Nenad; Chen, Gang

2014-07-21

Currently, steam generation using solar energy is based on heating bulk liquid to high temperatures. This approach requires either costly high optical concentrations leading to heat loss by the hot bulk liquid and heated surfaces or vacuum. New solar receiver concepts such as porous volumetric receivers or nanofluids have been proposed to decrease these losses. Here we report development of an approach and corresponding material structure for solar steam generation while maintaining low optical concentration and keeping the bulk liquid at low temperature with no vacuum. We achieve solar thermal efficiency up to 85% at only 10 kW m(-2). This high performance results from four structure characteristics: absorbing in the solar spectrum, thermally insulating, hydrophilic and interconnected pores. The structure concentrates thermal energy and fluid flow where needed for phase change and minimizes dissipated energy. This new structure provides a novel approach to harvesting solar energy for a broad range of phase-change applications.

The Preliminary Evaluation of Liquid Lubricants for Space Applications by Vacuum Tribometry

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.; Pepper, S. V.; Herrera-Fierro, P.; Feuchter, D.; Toddy, T. J.; Jayne, D. T.; Wheeler, D. R.; Abel, P. B.; Kingsbury, E.; Morales, W.

1994-01-01

Four different vacuum tribometers for the evaluation of liquid lubricants for space applications are described. These range from simple ball-on-flat sliders with maximum in-situ control and surface characterization to an instrument bearing apparatus having no in-situ characterization. Thus, the former provides an abundance of surface chemical information but is not particularly simulative of most triboelements. On the other hand, the instrument bearing apparatus is completely simulative, but only allows post-mortem surface chemical information. Two other devices, a four-ball apparatus and a ball-on-plate tribometer, provide varying degrees of surface chemical information and tribo-simulation. Examples of data from each device are presented.

Two-dimensional and three-dimensional dynamic imaging of live biofilms in a microchannel by time-of-flight secondary ion mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hua, Xin; Marshall, Matthew J.; Xiong, Yijia

2015-05-01

A vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface) was employed for in situ chemical imaging of live biofilms using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depth profiling by sputtering materials in sequential layers resulted in live biofilm spatial chemical mapping. 2D images were reconstructed to report the first 3D images of hydrated biofilm elucidating spatial and chemical heterogeneity. 2D image principal component analysis (PCA) was conducted among biofilms at different locations in the microchannel. Our approach directly visualized spatial and chemical heterogeneity within the living biofilm by dynamic liquid ToF-SIMS.

A study of thermal hydraulic and kinetic phenomena in HYLIFE-2: An inertial confinement fusion reactor

NASA Astrophysics Data System (ADS)

Chen, Xiang Ming

1993-01-01

Researchers have studied the different aspects of commercial fusion energy for several decades. A variety of inertial confinement fusion (ICF) reactors have been proposed. Different from the magnetic confinement fusion concept, inertial confinement fusion does not need long-term confinement of the fusion fuel but achieves fusion reaction in a short microexplosion under a high density, high temperature condition. The HYLIFE-2 reactor design started in 1987 is based on the study of a previous concept called HYLIFE (High Yield Lithium Injection Fusion Energy). Similar to the old concept, the HYLIFE-2 design uses a vacuum chamber in which D-T fusion pellets are injected and ignited by high energy beams shot into the reactor through different ports. The reactor vessel is protected from explosion radiations by a liquid fall (blanket) that also breeds tritium through the (n, alpha) reaction of lithium and conveys the fusion energy to the power cycle. In addition to some geometric chances, the new design replaces liquid metal lithium with the molten salt Flibe (Li2BeF4) as the protective blanket material. The objective was to remove the possibility of fire hazard. The important thermal hydraulic issues in the design are (1) equation of state of Flibe; (2) liquid relaxation after isochoric (constant volume) heating; (3) ablation and gas dynamics; (4) interaction of the vapor and liquid; and (5) condensation of the vaporized material. The first four issues have to do with the internal relaxation after the fusion microexplosion in the chamber. Vaporized material, as well as liquid, may assert strong impulses on the chamber wall during the process of relaxing after absorbing the energy from the microexplosion. Item (5) is related to the rapid vacuum recovery between the ignitions. Some aspects of the first four issues are studied.

RENEWABLE LIQUID GETTERING PUMP

DOEpatents

Batzer, T.H.

1962-08-21

A method and structure were developed for pumping gases by simple absorption into a liquid gettering material. The invention comprises means ror continuously pumping a liquid getterrng material from a reservoir to the top of a generally vertical surface disposed in a vacuum pumping chamber to receive gaseous and other particles in the liquid gettering material which continuously flows downward over the vertical suiface. Means are provided for continuous removal, degassing, and return of a portion of the liquid gettering material from the reservoir connected with collectrng means at the base of the generally vertical plate. (AEC)

Frequency modulation detection atomic force microscopy in the liquid environment

NASA Astrophysics Data System (ADS)

Jarvis, S. P.; Ishida, T.; Uchihashi, T.; Nakayama, Y.; Tokumoto, H.

True atomic resolution imaging using frequency modulation detection is already well established in ultra-high vacuum. In this paper we demonstrate that it also has great potential in the liquid environment. Using a combination of magnetic activation and high-aspect-ratio carbon nanotube probes, we show that imaging can be readily combined with point spectroscopy, revealing both the tip-sample interaction and the structure of the intermediate liquid.

Geometry of thin liquid sheet flows

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Calfo, Frederick D.; Mcconley, Marc W.; Mcmaster, Matthew S.; Afjeh, Abdollah A.

1994-01-01

Incompresible, thin sheet flows have been of research interest for many years. Those studies were mainly concerned with the stability of the flow in a surrounding gas. Squire was the first to carry out a linear, invicid stability analysis of sheet flow in air and compare the results with experiment. Dombrowski and Fraser did an experimental study of the disintegration of sheet flows using several viscous liquids. They also detected the formulation of holes in their sheet flows. Hagerty and Shea carried out an inviscid stability analysis and calculated growth rates with experimental values. They compared their calculated growth rates with experimental values. Taylor studied extensively the stability of thin liquid sheets both theoretically and experimentally. He showed that thin sheets in a vacuum are stable. Brown experimentally investigated thin liquid sheet flows as a method of application of thin films. Clark and Dumbrowski carried out second-order stability analysis for invicid sheet flows. Lin introduced viscosity into the linear stability analysis of thin sheet flows in a vacuum. Mansour and Chigier conducted an experimental study of the breakup of a sheet flow surrounded by high-speed air. Lin et al. did a linear stability analysis that included viscosity and a surrounding gas. Rangel and Sirignano carried out both a linear and nonlinear invisid stability analysis that applies for any density ratio between the sheet liquid and the surrounding gas. Now there is renewed interest in sheet flows because of their possible application as low mass radiating surfaces. The objective of this study is to investigate the fluid dynamics of sheet flows that are of interest for a space radiator system. Analytical expressions that govern the sheet geometry are compared with experimental results. Since a space radiator will operate in a vacuum, the analysis does not include any drag force on the sheet flow.

Ultrahigh performance heat spreader based on gas-liquid exfoliation boron nitride nanosheets.

PubMed

Ding, Jiheng; Zhao, Hongran; Wang, Qiaolei; Peng, Wanjun; Yu, Haibin

2017-11-24

Due to their high thermal conductivity and insulation performance, boron nitride nanosheets (BNNS) have great promise to fabricate thermal management equipment for application in power electronics. The liquid-phase exfoliation route has been regarded as the most commonly used approach to produce single and few-layered BNNS for many research fields. However, this process takes a long time, and the production yield is extremely low. In this work, an efficient technique to obtain few-layered (mostly < 5 layers), high-yield (∼33%), and plane-defect-free BNNS by the combination of liquid N 2 (L-N 2 ) gasification and liquid exfoliation was developed. The as-obtained BNNS suspensions could be vacuum filtered to make a thermal conductive film named a BNNS heat spreader which possessed a superior thermal conductivity of 61.2 W m -1 K -1 at room temperature. In addition, we also proved that the thermal conductivity of the BNNS heat spreader increased with the increase of density, creating an approach for fine tuning the thermal property of this heat spreader.

Ultrahigh performance heat spreader based on gas-liquid exfoliation boron nitride nanosheets

NASA Astrophysics Data System (ADS)

Ding, Jiheng; Zhao, Hongran; Wang, Qiaolei; Peng, Wanjun; Yu, Haibin

2017-11-01

Due to their high thermal conductivity and insulation performance, boron nitride nanosheets (BNNS) have great promise to fabricate thermal management equipment for application in power electronics. The liquid-phase exfoliation route has been regarded as the most commonly used approach to produce single and few-layered BNNS for many research fields. However, this process takes a long time, and the production yield is extremely low. In this work, an efficient technique to obtain few-layered (mostly < 5 layers), high-yield (˜33%), and plane-defect-free BNNS by the combination of liquid N2 (L-N2) gasification and liquid exfoliation was developed. The as-obtained BNNS suspensions could be vacuum filtered to make a thermal conductive film named a BNNS heat spreader which possessed a superior thermal conductivity of 61.2 W m-1 K-1 at room temperature. In addition, we also proved that the thermal conductivity of the BNNS heat spreader increased with the increase of density, creating an approach for fine tuning the thermal property of this heat spreader.

Methods of Testing Thermal Insulation and Associated Test Apparatus

NASA Technical Reports Server (NTRS)

Fesmire, James E. (Inventor); Augustynowicz, Stanislaw D. (Inventor)

2004-01-01

The system and method for testing thermal insulation uses a cryostatic insulation tester having a vacuum chamber and a cold mass including a test chamber and upper and lower guard chambers adjacent thereto. The thermal insulation is positioned within the vacuum chamber and adjacent the cold mass. Cryogenic liquid is supplied to the test chamber, upper guard and lower guard to create a first gas layer in an upper portion of the lower guard chamber and a second gas layer in an upper portion of the test chamber. Temperature are sensed within the vacuum chamber to test the thermal insulation.

Steam jet ejectors for the process industries. [Glossary included

DOE Office of Scientific and Technical Information (OSTI.GOV)

Power, R.B.

1994-01-01

Steam jet ejectors were for many years the workhorse of the chemical process industries for producing vacuum. With increasing emphasis on stricter pollution control, their use was curtailed. There are still many applications, however, such as those with large capacity requirements, where ejectors are the only equipment that can produce sufficient vacuum. Chapter 1 is a short overview on how to use the text. Chapter 2 discusses what an ejector is and how it works. How ejector stages work is reviewed in Chapter 3. Engineering calculations for ejector stages is thoroughly discussed in Chapter 4. In Chapter 5, contact andmore » surface condensers are reviewed, and calculation procedures are presented. The various types of pressure control are discussed in Chapter 6. Chapter 7 is an excellent review of installation of ejector vacuum systems. The final chapter of Part 2 (Chapters 3--8) thoroughly covers all aspects of operation, testing, troubleshooting and maintenance. Part 3, consisting of two chapters, is devoted to specifying and purchasing steam jet ejectors. Part 4 on other ejector applications and upgrading ejector usage also consists of two chapters. Chapter 11 reviews steam-jet refrigeration, steam-jet and gas-jet compressors, liquid jet eductors, desuperheaters, special design situations, and designing one's own systems. Upgrading of existing ejector procedures and hardware is reviewed in Chapter 12. The 12 appendixes cover: physical properties of common fluids; handy vacuum engineering data and rules of thumb; SI unit conversions; sizing air and steam metering orifices for testing; drill sizes; ejector operating costs and design optimization; forms for ejector calculations, tests, and inspections; instructions for preparing ejector specifications; test kit contents list; ejector manufacturers and suppliers of referenced hardware and information; and failure modes and symptoms.« less

Enabling liquid solvent structure analysis using hard x-ray absorption spectroscopy with a transferrable microfluidic reactor.

PubMed

Zheng, Jian; Zhang, Wei; Wang, Feng; Yu, Xiao-Ying

2018-05-10

In this paper, a vacuum compatible microfluidic device, system for analysis at the liquid vacuum interface, is integrated to hard x-ray absorption spectroscopy to obtain the local structure of K 3 [Fe(CN) 6 ] in aqueous solutions with three concentrations of 0.5 M, 0.05 M, and 0.005 M. The solutions were sealed in a microchannel 500 µm wide and 300 µm deep in a portable microfluidic device. The Fe K-edge x-ray absorption spectra indicate a presence of Fe(III) in the complex in water, with an octahedral geometry coordinated with 6 C atoms in the first shell with a distance of ~1.92 Å and 6 N atoms in the second shell with a distance of ~3.10 Å. Varying the concentration has no observable influence on the structure of K 3 [Fe(CN) 6 ]. Our results demonstrate the feasibility of using microfluidic based liquid cells in large synchrotron facilities. Using portable microfludic reactors provides a viable approach to enable multifaceted measurements of liquids in the future.

Enabling liquid solvent structure analysis using hard x-ray absorption spectroscopy with a transferrable microfluidic reactor

NASA Astrophysics Data System (ADS)

Zheng, Jian; Zhang, Wei; Wang, Feng; Yu, Xiao-Ying

2018-05-01

In this paper, a vacuum compatible microfluidic device, system for analysis at the liquid vacuum interface, is integrated to hard x-ray absorption spectroscopy to obtain the local structure of K3[Fe(CN)6] in aqueous solutions with three concentrations of 0.5 M, 0.05 M, and 0.005 M. The solutions were sealed in a microchannel 500 µm wide and 300 µm deep in a portable microfluidic device. The Fe K-edge x-ray absorption spectra indicate a presence of Fe(III) in the complex in water, with an octahedral geometry coordinated with 6 C atoms in the first shell with a distance of ~1.92 Å and 6 N atoms in the second shell with a distance of ~3.10 Å. Varying the concentration has no observable influence on the structure of K3[Fe(CN)6]. Our results demonstrate the feasibility of using microfluidic based liquid cells in large synchrotron facilities. Using portable microfludic reactors provides a viable approach to enable multifaceted measurements of liquids in the future.

Enabling liquid solvent structure analysis using hard x-ray absorption spectroscopy with a transferrable microfluidic reactor

DOE PAGES

Zheng, Jian; Zhang, Wei; Wang, Feng; ...

2018-04-11

In this study, a vacuum compatible microfluidic device, system for analysis at the liquid vacuum interface, is integrated to hard x-ray absorption spectroscopy to obtain the local structure of K 3[Fe(CN) 6] in aqueous solutions with three concentrations of 0.5 M, 0.05 M, and 0.005 M. The solutions were sealed in a microchannel 500 µm wide and 300 µm deep in a portable microfluidic device. The Fe K-edge x-ray absorption spectra indicate a presence of Fe(III) in the complex in water, with an octahedral geometry coordinated with 6 C atoms in the first shell with a distance of ~1.92 Åmore » and 6 N atoms in the second shell with a distance of ~3.10 Å. Varying the concentration has no observable influence on the structure of K 3[Fe(CN) 6]. Our results demonstrate the feasibility of using microfluidic based liquid cells in large synchrotron facilities. Using portable microfludic reactors provides a viable approach to enable multifaceted measurements of liquids in the future.« less

Enabling liquid solvent structure analysis using hard x-ray absorption spectroscopy with a transferrable microfluidic reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jian; Zhang, Wei; Wang, Feng

In this study, a vacuum compatible microfluidic device, system for analysis at the liquid vacuum interface, is integrated to hard x-ray absorption spectroscopy to obtain the local structure of K 3[Fe(CN) 6] in aqueous solutions with three concentrations of 0.5 M, 0.05 M, and 0.005 M. The solutions were sealed in a microchannel 500 µm wide and 300 µm deep in a portable microfluidic device. The Fe K-edge x-ray absorption spectra indicate a presence of Fe(III) in the complex in water, with an octahedral geometry coordinated with 6 C atoms in the first shell with a distance of ~1.92 Åmore » and 6 N atoms in the second shell with a distance of ~3.10 Å. Varying the concentration has no observable influence on the structure of K 3[Fe(CN) 6]. Our results demonstrate the feasibility of using microfluidic based liquid cells in large synchrotron facilities. Using portable microfludic reactors provides a viable approach to enable multifaceted measurements of liquids in the future.« less

Enabling liquid solvent structure analysis using hard x-ray absorption spectroscopy with a transferrable microfluidic reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jian; Zhang, Wei; Wang, Feng

In this paper, a vacuum compatible microfluidic device, System for Analysis at the Liquid Vacuum Interface (SALVI), is integrated to hard x-ray absorption spectroscopy (XAS) to obtain the local structure of K3[Fe(CN)6] in aqueous solutions with three concentrations of 0.5 M, 0.05 M, and 0.005 M. The solutions were sealed in a microchannel of 500 μm wide and 300 µm deep in a portable microfluidic device. The Fe K-edge x-ray absorption spectra show that the complex in water is Fe(III). The complex is present with octahedral geometry coordinated with 6 C atoms in the first shell with a distance ofmore » ~1.92 Å and 6 N atoms in the second shell with a distance of ~3.10 Å. Varying the concentration has no observable influence on the structure of K3[Fe(CN)6]. Our results demonstrate the feasibility of using microfluidic based liquid cells in large synchrotron facilities and it is a viable approach to enable multifaceted measurements of liquids in the future.« less

Advanced Vacuum Plasma Spray (VPS) for a Robust, Longlife and Safe Space Shuttle Main Engine (SSME)

NASA Technical Reports Server (NTRS)

Holmes, Richard R.; Elam, Sandra K.; McKechnie, Timothy N.; Power, Christopher A.

2010-01-01

In 1984, the Vacuum Plasma Spray Lab was built at NASA/Marshall Space Flight Center for applying durable, protective coatings to turbine blades for the space shuttle main engine (SSME) high pressure fuel turbopump. Existing turbine blades were cracking and breaking off after five hot fire tests while VPS coated turbine blades showed no wear or cracking after 40 hot fire tests. Following that, a major manufacturing problem of copper coatings peeling off the SSME Titanium Main Fuel Valve Housing was corrected with a tenacious VPS copper coating. A patented VPS process utilizing Functional Gradient Material (FGM) application was developed to build ceramic lined metallic cartridges for space furnace experiments, safely containing gallium arsenide at 1260 degrees centigrade. The VPS/FGM process was then translated to build robust, long life, liquid rocket combustion chambers for the space shuttle main engine. A 5K (5,000 Lb. thrust) thruster with the VPS/FGM protective coating experienced 220 hot firing tests in pristine condition with no wear compared to the SSME which showed blanching (surface pulverization) and cooling channel cracks in less than 30 of the same hot firing tests. After 35 of the hot firing tests, the injector face plates disintegrated. The VPS/FGM process was then applied to spraying protective thermal barrier coatings on the face plates which showed 50% cooler operating temperature, with no wear after 50 hot fire tests. Cooling channels were closed out in two weeks, compared to one year for the SSME. Working up the TRL (Technology Readiness Level) to establish the VPS/FGM process as viable technology, a 40K thruster was built and is currently being tested. Proposed is to build a J-2X size liquid rocket engine as the final step in establishing the VPS/FGM process TRL for space flight.

Influence of vacuum chamber impurities on the lifetime of organic light-emitting diodes

PubMed Central

Fujimoto, Hiroshi; Suekane, Takashi; Imanishi, Katsuya; Yukiwaki, Satoshi; Wei, Hong; Nagayoshi, Kaori; Yahiro, Masayuki; Adachi, Chihaya

2016-01-01

We evaluated the influence of impurities in the vacuum chamber used for the fabrication of organic light-emitting diodes on the lifetime of the fabricated devices and found a correlation between lifetime and the device fabrication time. The contact angle of the ITO substrates stored the chamber under vacuum were used to evaluate chamber cleanliness. Liquid chromatography-mass spectrometry was performed on Si wafers stored in the vacuum chamber before device fabrication to examine the impurities in the chamber. Surprisingly, despite the chamber and evaporation sources being at room temperature, a variety of materials were detected, including previously deposited materials and plasticizers from the vacuum chamber components. We show that the impurities, and not differences in water content, in the chamber were the source of lifetime variations even when the duration of exposure to impurities only varied before and after deposition of the emitter layer. These results suggest that the impurities floating in the vacuum chamber significantly impact lifetime values and reproducibility. PMID:27958304

Vacuum Radiance-Temperature Standard Facility for Infrared Remote Sensing at NIM

NASA Astrophysics Data System (ADS)

Hao, X. P.; Song, J.; Xu, M.; Sun, J. P.; Gong, L. Y.; Yuan, Z. D.; Lu, X. F.

2018-06-01

As infrared remote sensors are very important parts of Earth observation satellites, they must be calibrated based on the radiance temperature of a blackbody in a vacuum chamber prior to launch. The uncertainty of such temperature is thus an essential component of the sensors' uncertainty. This paper describes the vacuum radiance-temperature standard facility (VRTSF) at the National Institute of Metrology of China, which will serve to calibrate infrared remote sensors on Chinese meteorological satellites. The VRTSF can be used to calibrate vacuum blackbody radiance temperature, including those used to calibrate infrared remote sensors. The components of the VRTSF are described in this paper, including the VMTBB, the LNBB, the FTIR spectrometer, the reduced-background optical system, the vacuum chamber used to calibrate customers' blackbody, the vacuum-pumping system and the liquid-nitrogen-support system. The experimental methods and results are expounded. The uncertainty of the radiance temperature of VMTBB is 0.026 °C at 30 °C over 10 μm.

Influence of vacuum chamber impurities on the lifetime of organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Fujimoto, Hiroshi; Suekane, Takashi; Imanishi, Katsuya; Yukiwaki, Satoshi; Wei, Hong; Nagayoshi, Kaori; Yahiro, Masayuki; Adachi, Chihaya

2016-12-01

We evaluated the influence of impurities in the vacuum chamber used for the fabrication of organic light-emitting diodes on the lifetime of the fabricated devices and found a correlation between lifetime and the device fabrication time. The contact angle of the ITO substrates stored the chamber under vacuum were used to evaluate chamber cleanliness. Liquid chromatography-mass spectrometry was performed on Si wafers stored in the vacuum chamber before device fabrication to examine the impurities in the chamber. Surprisingly, despite the chamber and evaporation sources being at room temperature, a variety of materials were detected, including previously deposited materials and plasticizers from the vacuum chamber components. We show that the impurities, and not differences in water content, in the chamber were the source of lifetime variations even when the duration of exposure to impurities only varied before and after deposition of the emitter layer. These results suggest that the impurities floating in the vacuum chamber significantly impact lifetime values and reproducibility.

Investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non-vacuum or vacuum processes.

PubMed

Winter, S; Smith, A; Lappin, D; McDonagh, G; Kirk, B

2017-12-01

Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam sterilizers were tested: a non-vacuum benchtop sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop sterilizer (Lisa; W&H, Bürmoos, Austria). Each sterilizer cycle was completed with three handpieces and each cycle in triplicate. A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0-150 s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15 s equilibration time). The measurement point at the base of the handpiece failed in all test runs (N = 9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Determination of the Accomodation Coefficient Using Vapor/Gas Bubble Dynamics in an Acoustic Field

NASA Technical Reports Server (NTRS)

Gumerov, Nail A.

1999-01-01

Non-equilibrium liquid/vapor phase transformations can occur in superheated or subcooled liquids in fast processes such as in evaporation in a vacuum, in processing of molten metals, and in vapor explosions. The rate at which such a phase transformation occurs, Xi, can be described by the Hertz-Knudsen-Langmuir formula. More than one century of the history of the accommodation coefficient measurements shows many problems with its determination. This coefficient depends on the temperature, is sensitive to the conditions at the interface, and is influenced by small amounts of impurities. Even recent measurements of the accommodation coefficient for water (Hagen et al, 1989) showed a huge variation in Beta from 1 for 1 micron droplets to 0.006 for 15 micron droplets. Moreover, existing measurement techniques for the accommodation coefficient are complex and expensive. Thus development of a relatively inexpensive and reliable technique for measurement of the accommodation coefficient for a wide range of substances and temperatures is of great practical importance.

Design of a liquid membrane target for high repetition rate neutron generation

NASA Astrophysics Data System (ADS)

Poole, Patrick; Andereck, C. David; Storm, Mike; Schumacher, Douglass

2013-10-01

Ultra-bright, pulsed, spatially-small sources of energetic neutrons have applications in radiography and non-destructive remote sensing. Neutrons can be generated by a process wherein ions accelerated from a laser-irradiated primary target subsequently bombard a converter material, causing neutron-producing nuclear reactions, such as 7Li(d,n)8Be. Deuterons from this process are suppressed by contamination that builds up on the rear of the solid primary target. To eliminate this issue we propose a self-replenishing liquid membrane target consisting of heavy water and deuterated surfactant, formed in-vacuum within a moveable wire frame. In addition to removing issues associated with solid target positioning and collateral damage, this apparatus provides flow rate and target thickness control, and allows for the high repetition rates required to generate desired neutron fluxes with a portable laser-based system. The apparatus design will be presented, as well as a novel interferometric method that measures the membrane thickness using tightly-focused light. This work was performed with support from DARPA.

Fabrication of n-type Si nanostructures by direct nanoimprinting with liquid-Si ink

NASA Astrophysics Data System (ADS)

Takagishi, Hideyuki; Masuda, Takashi; Yamazaki, Ken; Shimoda, Tatsuya

2018-01-01

Nanostructures of n-type amorphous silicon (a-Si) and polycrystalline silicon (poly-Si) with a height of 270 nm and line widths of 110-165 nm were fabricated directly onto a substrate through a simple imprinting process that does not require vacuum conditions or photolithography. The n-type Liquid-Si ink was synthesized via photopolymerization of cyclopentasilane (Si5H10) and white phosphorus (P4). By raising the temperature from 160 °C to 200 °C during the nanoimprinting process, well-defined angular patterns were fabricated without any cracking, peeling, or deflections. After the nanoimprinting process, a-Si was produced by heating the nanostructures at 400°C-700 °C, and poly-Si was produced by heating at 800 °C. The dopant P diffuses uniformly in the Si films, and its concentration can be controlled by varying the concentration of P4 in the ink. The specific resistance of the n-type poly-Si pattern was 7.0 × 10-3Ω ṡ cm, which is comparable to the specific resistance of flat n-type poly-Si films.

Relative Lifetimes of Several Space Liquid Lubricants Using a Vacuum Spiral Orbit Tribometer (SOT)

NASA Technical Reports Server (NTRS)

Jansen, Mark J.; Jones, William R., Jr.; Predmore, Roamer E.; Loewenthal, Stuart L.

2001-01-01

A vacuum spiral orbit rolling contact tribometer (SOT) was used to determine the relative lifetimes of several unformulated space liquid lubricants. The lubricants tested included a synthetic hydrocarbon (Pennzane 2001 A), three perfluoropolyethers (Krytox 143AC, Fomblin Z25, and Brayco 815Z), three silahydrocarbons (a tri, a tetra, and a penta) and a polyalphaolefin (Nye PAO-100). The SOT simulates the ball motions in an angular contact bearing and tribochemically degrades microgram quantities of lubricant. Test failure is determined when a preset friction coefficient is exceeded. Relative lifetime (orbits/micro-g) is defined as the number of ball orbits to failure divided by the amount of lubricant on the ball. Conditions included 10 to 200 rpm rotational speed, approximately 50 micro-g lubricant, an initial vacuum < 1.3x10(exp -6) Pa, room temperature (approximately 23 C), a mean Hertzian stress of 1.5 GPa, and 440 C stainless steel specimens. Lubricated lifetimes from longest to shortest were Pennzane 2001 A, the silahydrocarbons and the PAO-100, 143AC, ZI-5, and then 815Z. Relative lifetimes compare favorably to full-scale vacuum gimbal bearing tests. The effect of varying the mean Hertzian stress on the lifetime of some of the lubricants was examined.

Evaluation of an In-Situ, Liquid Lubrication System for Space Mechanisms Using a Vacuum Spiral Orbit Tribometer

NASA Technical Reports Server (NTRS)

Jansen, Mark J.; Jones, William R., Jr.; Pepper, Stephen V.

2002-01-01

Many moving mechanical assemblies (MMAs) for space applications rely on a small, initial charge of lubricant for the entire mission lifetime, often in excess of five years. In many cases, the premature failure of a lubricated component can result in mission failure. If lubricant could be resupplied to the contact in-situ, the life of the MMA could be extended. A vacuum spiral orbit tribometer (SOT) was modified to accept a device to supply re-lubrication during testing. It was successfully demonstrated that a liquid lubricant (Pennzane (Registered Trademark)/Nye 2001A) could be evaporated into a contact during operation, lowering the friction coefficient and therefore extending the life of the system.

Inverse Coarse-Graining: A New Tool for Molecular Design

DTIC Science & Technology

2010-12-16

simulations. When compared with the more general multiscale coarse-graining (MS-CG) method, the EF-CG method retains the transferable part of the CG...Y.; Yan, T.; Voth, G. A., A Multiscale coarse-graining study of liquid/vacuum interface of room-temperature ionic liquids with alkyl substituents of...Energetic Room Temperature Ionic Liquid 1-Hydroxyethyl-4Amino-1, 2, 4-Triazolium Nitrate (HEATN). J. Phys. Chem. B 2008, 112, 3121-3131. 6. Liu, P

Apparatus and method for carbon fiber surface treatment

DOEpatents

Paulauskas, Felix L; Sherman, Daniel M

2014-06-03

An apparatus and method for enhancing the surface energy and/or surface chemistry of carbon fibers involves exposing the fibers to direct or indirect contact with atmospheric pressure plasma generated using a background gas containing at least some oxygen or other reactive species. The fiber may be exposed directly to the plasma, provided that the plasma is nonfilamentary, or the fiber may be exposed indirectly through contact with gases exhausting from a plasma discharge maintained in a separate volume. In either case, the process is carried out at or near atmospheric pressure, thereby eliminating the need for vacuum equipment. The process may be further modified by moistening the fibers with selected oxygen-containing liquids before exposure to the plasma.

Apparatus and method for carbon fiber surface treatment

DOEpatents

Paulauskas, Felix L [Knoxville, TN; Sherman, Daniel M [Knoxville, TN

2012-07-24

An apparatus and method for enhancing the surface energy and/or surface chemistry of carbon fibers involves exposing the fibers to direct or indirect contact with atmospheric pressure plasma generated using a background gas containing at least some oxygen or other reactive species. The fiber may be exposed directly to the plasma, provided that the plasma is nonfilamentary, or the fiber may be exposed indirectly through contact with gases exhausting from a plasma discharge maintained in a separate volume. In either case, the process is carried out at or near atmospheric pressure, thereby eliminating the need for vacuum equipment. The process may be further modified by moistening the fibers with selected oxygen-containing liquids before exposure to the plasma.

Effect of aging at 1040 C (1900 F) on the ductility and structure of a tantalum alloy, T-111

NASA Technical Reports Server (NTRS)

Watson, G. K.; Stephens, J. R.

1972-01-01

The post-aging embrittlement of T-111 (tantalum - 8-percent tungsten - 2-percent hafnium) following exposure for up to about 10,000 hours at 1040 C in either vacuum or liquid lithium was investigated for sheet and tubing samples. This thermal aging was shown to greatly increase the sensitivity of T-111 to hydrogen embrittlement during subsequent room temperature specimen processing or testing. The hydrogen embrittlement problem can be avoided by preventing exposure to the T-111 to moisture during post-aging processing or testing. Aging at 1040 C also resulted in formation of HfO2 particles at grain boundaries, which may contribute to the observed embrittlement.

A nanosecond pulsed laser heating system for studying liquid and supercooled liquid films in ultrahigh vacuum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Yuntao; Dibble, Collin J.; Petrik, Nikolay G.

2016-04-26

A pulsed laser heating system has been developed that enables investigations of the dynamics and kinetics of nanoscale liquid films and liquid/solid interfaces on the nanosecond timescale in ultrahigh vacuum (UHV). Details of the design, implementation and characterization of a nanosecond pulsed laser system for transiently heating nanoscale films are described. Nanosecond pulses from a Nd:YAG laser are used to rapidly heat thin films of adsorbed water or other volatile materials on a clean, well-characterized Pt(111) crystal in UHV. Heating rates of ~1010 K/s for temperature increases of ~100 – 200 K are obtained. Subsequent rapid cooling (~5 × 109more » K/s) quenches the film, permitting in-situ, post-mortem analysis using a variety of surface science techniques. Lateral variations in the laser pulse energy are ~ ± 3% leading to a temperature uncertainty of ~ ± 5 K for a temperature jump of 200 K. Initial experiments with the apparatus demonstrate that crystalline ice films initially held at 90 K can be rapidly transformed into liquid water films with T > 273 K. No discernable recrystallization occurs during the rapid cooling back to cryogenic temperatures. In contrast, amorphous solid water films heated below the melting point rapidly crystallize. The nanosecond pulsed laser heating system can prepare nanoscale liquid and supercooled liquid films that persist for nanoseconds per heat pulse in an UHV environment, enabling experimental studies of a wide range of phenomena in liquids and at liquid/solid interfaces.« less

A nanosecond pulsed laser heating system for studying liquid and supercooled liquid films in ultrahigh vacuum.

PubMed

Xu, Yuntao; Dibble, Collin J; Petrik, Nikolay G; Smith, R Scott; Joly, Alan G; Tonkyn, Russell G; Kay, Bruce D; Kimmel, Greg A

2016-04-28

A pulsed laser heating system has been developed that enables investigations of the dynamics and kinetics of nanoscale liquid films and liquid/solid interfaces on the nanosecond time scale in ultrahigh vacuum (UHV). Details of the design, implementation, and characterization of a nanosecond pulsed laser system for transiently heating nanoscale films are described. Nanosecond pulses from a Nd:YAG laser are used to rapidly heat thin films of adsorbed water or other volatile materials on a clean, well-characterized Pt(111) crystal in UHV. Heating rates of ∼10(10) K/s for temperature increases of ∼100-200 K are obtained. Subsequent rapid cooling (∼5 × 10(9) K/s) quenches the film, permitting in-situ, post-heating analysis using a variety of surface science techniques. Lateral variations in the laser pulse energy are ∼±2.7% leading to a temperature uncertainty of ∼±4.4 K for a temperature jump of 200 K. Initial experiments with the apparatus demonstrate that crystalline ice films initially held at 90 K can be rapidly transformed into liquid water films with T > 273 K. No discernable recrystallization occurs during the rapid cooling back to cryogenic temperatures. In contrast, amorphous solid water films heated below the melting point rapidly crystallize. The nanosecond pulsed laser heating system can prepare nanoscale liquid and supercooled liquid films that persist for nanoseconds per heat pulse in an UHV environment, enabling experimental studies of a wide range of phenomena in liquids and at liquid/solid interfaces.

Lightweight thermally efficient composite feedlines, preliminary design and evaluation. [for the space tug propulsion system

NASA Technical Reports Server (NTRS)

Spond, D. E.; Holzworth, R. E.; Hall, C. A.

1974-01-01

Six liquid hydrogen feedline design concepts were developed for the cryogenic space tug. The feedlines include composite and all-metal vacuum jacketed and non-vacuum jacketed concepts, and incorporate the latest technology developments in the areas of thermally efficient vacuum jacket end closures and standoffs, radiation shields in the vacuum annulus, thermal coatings, and lightweight dissimilar metal flanged joints. The feedline design concepts were evaluated on the basis of thermal performance, weight, cost, reliability, and reusability. It is shown that composite tubing provides improved thermal performance and reduced weight for each design concept considered. Approximately 12 kg (26 lb.) can be saved by the use of composite tubing for the LH2 feedline and the other propulsion lines in the space tug.

Improving the lateral resolution of quartz tuning fork-based sensors in liquid by integrating commercial AFM tips into the fiber end.

PubMed

Gonzalez, Laura; Martínez-Martín, David; Otero, Jorge; de Pablo, Pedro José; Puig-Vidal, Manel; Gómez-Herrero, Julio

2015-01-14

The use of quartz tuning fork sensors as probes for scanning probe microscopy is growing in popularity. Working in shear mode, some methods achieve a lateral resolution comparable with that obtained with standard cantilevered probes, but only in experiments conducted in air or vacuum. Here, we report a method to produce and use commercial AFM tips in electrically driven quartz tuning fork sensors operating in shear mode in a liquid environment. The process is based on attaching a standard AFM tip to the end of a fiber probe which has previously been sharpened. Only the end of the probe is immersed in the buffer solution during imaging. The lateral resolution achieved is about 6 times higher than that of the etched microfiber on its own.

Effective Porosity Measurements by Wet- and Dry-type Vacuum Saturations using Process-Programmable Vacuum Saturation System

NASA Astrophysics Data System (ADS)

Lee, T. J.; Lee, K. S., , Dr; Lee, S. K.

2017-12-01

One of the most important factors in measuring effective porosity by vacuum saturation method is that the air in the pore space can be fully substituted by water during the vacuum saturation process. International Society of Rock Mechanics (ISRM) suggests vacuuming a rock sample submerged in the water, while American Society of Test and Materials (ASTM) vacuuming the sample and water separately and then pour the water to the sample. In this study, we call the former wet-type vacuum saturation (WVS) method and the latter dry-type vacuum saturation (DVS) method, and compare the effective porosity measured by the two different vacuum saturation processes. For that purpose, a vacuum saturation system has been developed, which can support both WVS and DVS by only changing the process by programming. Comparison of effective porosity has been made for a cement mortar and rock samples. As a result, DVS can substitute more void volume to water than WVS, which in turn insists that DVS can provide more exact value of effective porosity than WVS.

Tribological characteristics of perfluoropolyether liquid lubricants under sliding conditions in high vacuum

NASA Technical Reports Server (NTRS)

Masuko, Masabumi; Jones, William R., Jr.; Helmick, Larry S.

1993-01-01

Tribological characteristics of three PFPE's (Fomblin Z, Demnum, and Krytox) were studied under high vacuum using a four-ball apparatus with 440C steel specimens. Fomblin Z and Demnum exhibited initial scuffing-like high friction whereas Krytox did not. Steady state friction with Fomblin Z was the lowest among the three oils. Frictional values for Demnum and Krytox were almost the same. The lowest wear rate in air was provided by Krytox regardless of load, and low wear rates in vacuum at high load were achieved with Krytox and Demnum. Results are explained by reactivity and pressure-viscosity characteristics of the oils.

A Novel Lithium-ion Laminated Pouch Cell Tested For Performance And Safety

NASA Technical Reports Server (NTRS)

Jeevarajan, Judith A.; Inoue, Takefumi

2006-01-01

A new Li-ion 4.0 Ah pouch cell from GS Yuasa has been tested to determine its performance and safety. The cell is of a laminate pouch design with liquid electrolyte. The rate, thermal and vacuum performance capabilities have been tested to determine the optimum parameters. Under vacuum conditions, the cells were cycled under restrained and unrestrained configurations. The burst pressure of the laminate pouch was also determined. The overcharge, overdischarge into reversal and external short circuit safety tests were also performed to determine the cell s tolerance to abuse. Key Words: Li-ion, safety, vacuum test, abuse, COTS batteries, rate capability

Spiral Orbit Tribometry. 2; Evaluation of Three Liquid Lubricants in Vacuum

NASA Technical Reports Server (NTRS)

Pepper, Stephen V.; Kingsbury, Edward P.; Kiraly, Louis J. (Technical Monitor)

2002-01-01

The coefficients of friction and relative degradation rates of three lubricants run in the boundary regime in vacuum are evaluated in a Spiral Orbit Tribometer. This tribometer subjected the lubricants to rolling contact conditions similar to those found in angular contact ball bearings. A multiply alkylated cyclopentane (MAC) hydrocarbon lubricant suffered degradation at a rate almost two orders of magnitude less than the degradation rate of two perfluoropolyalkylether (PFPE) lubricants.

Analysis of a space emergency ammonia dump using the FLOW-NET two-phase flow program

NASA Technical Reports Server (NTRS)

Navickas, J.; Rivard, W. C.

1992-01-01

Venting of cryogenic and non-cryogenic fluids to a vacuum or a very low pressure will take place in many space-based systems that are currently being designed. This may cause liquid freezing either internally within the flow circuit or on external spacecraft surfaces. Typical ammonia flow circuits were investigated to determine the effect of the geometric configuration and initial temperature, pressure, and void fraction on the freezing characteristics of the system. The analysis was conducted also to investigate the ranges of applicability of the FLOW-NET program. It was shown that a typical system can be vented to very low liquid fractions before freezing occurs. However, very small restrictions in the flow circuit can hasten the inception of freezing. The FLOW-NET program provided solutions over broad ranges of system conditions, such as venting of an ammonia tank, initially completely filled with liquid, through a series of contracting and expanding line cross sections to near-vacuum conditions.

Comparison of a novel distillation method versus a traditional distillation method in a model gin system using liquid/liquid extraction.

PubMed

Greer, Derek; Pfahl, Les; Rieck, Jim; Daniels, Tim; Garza, Oscar

2008-10-08

This research studied a novel form of distillation (high vacuum distillation) as a method for preserving volatile aroma chemicals important to the organoleptic attributes of a four botanical model gin as well as the degradation products generated during the heating required in traditional methods of gin distillation. A 2 (5) factorial experiment was conducted in a partially confounded incomplete block design and analyzed using the PROC MIXED procedure from SAS. A model gin was made of dried juniper berries (Juniperus communis), coriander seed (Coriandrum sativum), angelica root (Angelica archangelica), and dry lemon peel (Citrus limonum). This was distilled on a traditional still utilizing atmospheric pressure and a heating mantel to initiate phase separation as well as a novel still (high vacuum) utilizing high vacuum pressures below 0.1 mmHg and temperatures below -15 degrees C to initiate phase separation. The degradation products (alpha-pinene, alpha-phellandrene, E-caryophyllene, and beta-myrcene) were present at greater levels (approximately 10 times) in the traditional still-made gin as compared to the novel gin.

Design and Development of the Liquid Lithium Limiter (L3) for CDX-U

NASA Astrophysics Data System (ADS)

Seraydarian, R. P.; Chousal, L.; Doerner, R. P.; Luckhardt, S. C.; Lynch, T.

2000-10-01

--- This poster describes experiments with liquid Li that informed the design of a Liquid Lithium Limter (L3) built by UCSD for installation on the CDX-U spherical torus at PPPL. It was necessary to resort to wetting liquid Li to textured structures in order for the limiter to intercept 2-3 density e-folding lengths of the scrape off layer (3 cm) of the CDX-U plasma. Since Li is chemically active and corrodes rapidly in all but the driest air, we carried out wetting experiments in vacuum (10-7 - 10-8 torr) and also in Ar at near atmospheric pressure. Wetting of steel occurred reliably at substrate temperatures near 500 ^oC under all conditions, but this high temperature presented special problems of rapid material loss through evaporation, especially under vacuum. Once the surface is wetted, however, lost Li can be replenished at ~ 200 ^oC (just above the melting temperature) where evaporation is negligible. A wetted limiter can even be cooled to room temperature and then reheated many hours later as long as clean conditions are maintained. Surface textures, heating techniques, effective seal materials for piston-driven liquid Li reservoirs, and other aspects of the limiter system design will be presented. Work supported by US DOE grant DE-FG03-95ER54301

A hybrid liquid-phase precipitation (LPP) process in conjunction with membrane distillation (MD) for the treatment of the INEEL sodium-bearing liquid waste.

PubMed

Bader, M S H

2005-05-20

A novel hybrid system combining liquid-phase precipitation (LPP) and membrane distillation (MD) is integrated for the treatment of the INEEL sodium-bearing liquid waste. The integrated system provides a "full separation" approach that consists of three main processing stages. The first stage is focused on the separation and recovery of nitric acid from the bulk of the waste stream using vacuum membrane distillation (VMD). In the second stage, polyvalent cations (mainly TRU elements and their fission products except cesium along with aluminum and other toxic metals) are separated from the bulk of monovalent anions and cations (dominantly sodium nitrate) by a front-end LPP. In the third stage, MD is used first to concentrate sodium nitrate to near saturation followed by a rear-end LPP to precipitate and separate sodium nitrate along with the remaining minor species from the bulk of the aqueous phase. The LPP-MD hybrid system uses a small amount of an additive and energy to carry out the treatment, addresses multiple critical species, extracts an economic value from some of waste species, generates minimal waste with suitable disposal paths, and offers rapid deployment. As such, the LPP-MD could be a valuable tool for multiple needs across the DOE complex where no effective or economic alternatives are available.

Robot design for a vacuum environment

NASA Technical Reports Server (NTRS)

Belinski, S.; Trento, W.; Imani-Shikhabadi, R.; Hackwood, S.

1987-01-01

The cleanliness requirements for many processing and manufacturing tasks are becoming ever stricter, resulting in a greater interest in the vacuum environment. Researchers discuss the importance of this special environment, and the development of robots which are physically and functionally suited to vacuum processing tasks. Work is in progress at the Center for robotic Systems in Microelectronics (CRSM) to provide a robot for the manufacture of a revolutionary new gyroscope in high vacuum. The need for vacuum in this and other processes is discussed as well as the requirements for a vacuum-compatible robot. Finally, researchers present details on work done at the CRSM to modify an existing clean-room compatible robot for use at high vacuum.

Redesigning the continuous vacuum sealer packaging machine to improve the processing speed

NASA Astrophysics Data System (ADS)

Belo, J. B.; Widyanto, S. A.; Jamari, J.

2017-01-01

Vacuum sealer as a product packaging tool of food products to be able to vacuum air inside the plastic which is filled with food products and it causes the pressure lower. In this condition, the optimal heating temperature is reached in a shorter time, so that damage on plastic sealer of vacuumed food products could be prevented to be more effective and efficient. The purpose of this redesigning is to design a vacuum sealer packaging machine continuously through a conveyor mechanism on the packaging quality, time of processing speed of vacuuming food product in the plastic package. This designing process is conducted through several steps of designing and constructing tools until the products are ready to operate. Data analysis is done through quality test of vacuum and sealer to the plastic thickness of 75 µm, 80 µm, and 100 µm with temperature of 170°C, 180°C, 190°C and vacuum duration of 5 seconds, 8 seconds, and 60 seconds. Results of this designing process indicate that vacuum sealer works practically and more optimally with the time of vacuum processing speed of 0 to 1 minute/s; whereas, the pressure of vacuuming suction is until 1e-5 MPa. The results of tensile strength test are at a maximum of 32,796 (N/mm2) and a minimum of 20,155 (N/mm2) and the analysis of plastic composite with EDX. This result shows that the vacuum pressure and the quality of vacuum sealer are better and more efficient.

Sonoluminescence Explained by the Standpoint of Coherent Quantum Vacuum Dynamics and its Prospects for Energy Production

NASA Astrophysics Data System (ADS)

Maxmilian Caligiuri, Luigi; Musha, Takaaki

Sonoluminescence, or its more frequently studied version known as Single Bubble Sonoluminescence, consisting in the emission of light by a collapsing bubble in water under ultrasounds, represents one of the most challenging and interesting phenomenon in theoretical physics. In fact, despite its relatively easy reproducibility in a simple laboratory, its understanding within the commonly accepted picture of condensed matter remained so far unsatisfactory. On the other hand, the possibility to control the physical process involved in sonoluminescence, representing a sort of nuclear fusion on small scale, could open unthinkable prospects of free energy production from water. Different explanations has been proposed during the past years considering, in various way, the photoemission to be related to electromagnetic Zero Point Field energy dynamics, by considering the bubble surface as a Casimir force boundary. More recently a model invoking Cherenkov radiation emission from superluminal photons generated in quantum vacuum has been successfully proposed. In this paper it will be shown that the same results can be more generally explained and quantitative obtained within a QED coherent dynamics of quantum vacuum, according to which the electromagnetic energy of the emitted photons would be related to the latent heat involved in the phase transition from water's vapor to liquid phase during the bubble collapse. The proposed approach could also suggest an explanation of a possible mechanism of generation of faster than light (FTL) photons required to start Cherenkov radiation as well as possible applications to energy production from quantum vacuum.

Preform Characterization in VARTM Process Model Development

NASA Technical Reports Server (NTRS)

Grimsley, Brian W.; Cano, Roberto J.; Hubert, Pascal; Loos, Alfred C.; Kellen, Charles B.; Jensen, Brian J.

2004-01-01

Vacuum-Assisted Resin Transfer Molding (VARTM) is a Liquid Composite Molding (LCM) process where both resin injection and fiber compaction are achieved under pressures of 101.3 kPa or less. Originally developed over a decade ago for marine composite fabrication, VARTM is now considered a viable process for the fabrication of aerospace composites (1,2). In order to optimize and further improve the process, a finite element analysis (FEA) process model is being developed to include the coupled phenomenon of resin flow, preform compaction and resin cure. The model input parameters are obtained from resin and fiber-preform characterization tests. In this study, the compaction behavior and the Darcy permeability of a commercially available carbon fabric are characterized. The resulting empirical model equations are input to the 3- Dimensional Infiltration, version 5 (3DINFILv.5) process model to simulate infiltration of a composite panel.

Germanium detector vacuum encapsulation

NASA Technical Reports Server (NTRS)

Madden, N. W.; Malone, D. F.; Pehl, R. H.; Cork, C. P.; Luke, P. N.; Landis, D. A.; Pollard, M. J.

1991-01-01

This paper describes an encapsulation technology that should significantly improve the viability of germanium gamma-ray detectors for a number of important applications. A specialized vacuum chamber has been constructed in which the detector and the encapsulating module are processed in high vacuum. Very high vacuum conductance is achieved within the valveless encapsulating module. The detector module is then sealed without breaking the chamber vacuum. The details of the vacuum chamber, valveless module, processing, and sealing method are presented.

Polymerisation processes in expoy resins under influence of free space environment

NASA Astrophysics Data System (ADS)

Kondyurin, A.; Lauke, B.; Kondyurina, I.

A creation of large size constructions in space or on celestial bodies is possible by the way of chemical reactions of liquid viscous components under space environment conditions [1-2]. In particular, a new technology for large-size space module for electronic components, energy and materials production is developed on the basis of polymerisation technique. The factors of free space environment have a significant influence on the polymerisation processes. The polymerisation processes in active liquid components are sensitive to microgravitation, temperature variations (-150{ldots}+1500C), high vacuum (10-3{ldots}10-7 Pa), atomic oxygen flux (on LEO), UV and VUV irradiations, X-ray and γ -irradiations, high energy electron and ion fluxes. Experiments of polymerisation processes under simulated free space conditions were conducted. The influences of high vacuum, high energy ion beam and rf- and mw-plasma on polymerisation of epoxy resins were observed. The effects of low molecular components evaporations, free radical formations, additional chemical reactions and mixing processes during polymerisation were observed. Our results showed, that the space factors can initiate the polymerisation reaction in epoxy matrix of glass and carbon fibre composites. The result can be used for a technology for large size constructions on Earth orbit, in far space and on space bodies as for deployed antennas, solar sail stringers, solar shield stringers, frame for large-size space station, frame for Moon, Mars, asteroids bases, frame for space plant on Earth orbit and on other celestial bodies. The study was partially supported by Alexander von Humboldt Foundation (A. Kondyurin) and European Space Agency, ESTEC (contract 17083/03/NL/Sfe "Space Environmental Effects on the Polymerisation of Composite Structures"). 1. A.Kondyurin, B.Lauke, Polymerisation processes in simulated free space conditions, Proceedings of the 9th International Symposium on Materials in a Space Environment, Noordwijk, The Netherlands, 16-20 June, 2003, ESA SP-540, September 2003, pp.75-80. 2. V.A.Briskman, T.M.Yudina, K.G.Kostarev, A.V.Kondyurin, V.B.Leontyev, M.G.Levkovich, A.L.Mashinsky, G.S.Nechitailo, Polymerization in microgravity as a new process in space technology, Acta Astronautica, vol.48, N2-3, 2001, pp.169-180.

Measurement of actinides and strontium-90 in high activity waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxwell, S.L. III; Nelson, M.R.

1994-08-01

The reliable measurement of trace radionuclides in high activity waste is important to support waste processing activities at SRS (F and H Area Waste Tanks, Extended Sludge Processing (ESP) and In-Tank precipitation (ITP) processing). Separation techniques are needed to remove high levels of gamma activity and alpha/beta interferences prior to analytical measurement. Using new extraction chromatographic resins from EiChrom Industries, Inc., the SRS Central Laboratory has developed new high speed separation methods that enable measurement of neptunium, thorium, uranium, plutonium, americium and strontium-90 in high activity waste solutions. Small particle size resin and applied vacuum are used to reduce analysismore » times and enhance column performance. Extraction chromatographic resins are easy to use and eliminate the generation of contaminated liquid organic waste.« less

Implementation of Leak Test Methods for the International Space Station (ISS) Elements, Systems and Components

NASA Technical Reports Server (NTRS)

Underwood, Steve; Lvovsky, Oleg

2007-01-01

The International Space Station (ISS has Qualification and Acceptance Environmental Test Requirements document, SSP 41172 that includes many environmental tests such as Thermal vacuum & Cycling, Depress/Repress, Sinusoidal, Random, and Acoustic Vibration, Pyro Shock, Acceleration, Humidity, Pressure, Electromatic Interference (EMI)/Electromagnetic Compatibility (EMCO), etc. This document also includes (13) leak test methods for Pressure Integrity Verification of the ISS Elements, Systems, and Components. These leak test methods are well known, however, the test procedure for specific leak test method shall be written and implemented paying attention to the important procedural steps/details that, if omitted or deviated, could impact the quality of the final product and affect the crew safety. Such procedural steps/details for different methods include, but not limited to: - Sequence of testing, f or example, pressurization and submersion steps for Method I (Immersion); - Stabilization of the mass spectrometer leak detector outputs fo r Method II (vacuum Chamber or Bell jar); - Proper data processing an d taking a conservative approach while making predictions for on-orbit leakage rate for Method III(Pressure Change); - Proper Calibration o f the mass spectrometer leak detector for all the tracer gas (mostly Helium) Methods such as Method V (Detector Probe), Method VI (Hood), Method VII (Tracer Probe), Method VIII(Accumulation); - Usage of visibl ility aides for Method I (Immersion), Method IV (Chemical Indicator), Method XII (Foam/Liquid Application), and Method XIII (Hydrostatic/Visual Inspection); While some methods could be used for the total leaka ge (either internal-to-external or external-to-internal) rate requirement verification (Vacuum Chamber, Pressure Decay, Hood, Accumulation), other methods shall be used only as a pass/fail test for individual joints (e.g., welds, fittings, and plugs) or for troubleshooting purposes (Chemical Indicator, Detector Probe, Tracer Probe, Local Vacuum Chamber, Foam/Liquid Application, and Hydrostatic/Visual Inspection). Any isolation of SSP 41172 requirements have led to either retesting of hardware or accepting a risk associated with the potential system or component pressure integrity problem during flight.

Liquid lithium target as a high intensity, high energy neutron source

DOEpatents

Parkin, Don M.; Dudey, Norman D.

1976-01-01

This invention provides a target jet for charged particles. In one embodiment the charged particles are high energy deuterons that bombard the target jet to produce high intensity, high energy neutrons. To this end, deuterons in a vacuum container bombard an endlessly circulating, free-falling, sheet-shaped, copiously flowing, liquid lithium jet that gushes by gravity from a rectangular cross-section vent on the inside of the container means to form a moving web in contact with the inside wall of the vacuum container. The neutrons are produced via break-up of the beam in the target by stripping, spallation and compound nuclear reactions in which the projectiles (deuterons) interact with the target (Li) to produce excited nuclei, which then "boil off" or evaporate a neutron.

ASDA - Advanced Suit Design Analyzer computer program

NASA Technical Reports Server (NTRS)

Bue, Grant C.; Conger, Bruce C.; Iovine, John V.; Chang, Chi-Min

1992-01-01

An ASDA model developed to evaluate the heat and mass transfer characteristics of advanced pressurized suit design concepts for low pressure or vacuum planetary applications is presented. The model is based on a generalized 3-layer suit that uses the Systems Integrated Numerical Differencing Analyzer '85 in conjunction with a 41-node FORTRAN routine. The latter simulates the transient heat transfer and respiratory processes of a human body in a suited environment. The user options for the suit encompass a liquid cooled garment, a removable jacket, a CO2/H2O permeable layer, and a phase change layer.

Shelf-stable food through high dose irradiation

NASA Astrophysics Data System (ADS)

Plaček, V.; Svobodová, V.; Bartoníček, B.; Rosmus, J.; Čamra, M.

2004-09-01

Irradiation of food with high doses (radappertization) is a way, how to prepare shelf-stable ready-to-eat food. The radappertization process requires that the food be heated at first to an internal temperature of at least 75°C to inactivate autolytic enzyme, which could cause the spoilage during storage without refrigeration. In order to prevent radiation induced changes in sensory properties (off flavors, odors, undesirable color change, etc.) the food was vacuum packed and irradiated in frozen state at -30°C or less to a minimum dose of 35 kGy. Such products have characteristics of fresh food prepared for eating even if they are stored for long time under tropical conditions. The wholesomeness (safety for consumption) has been confirmed during 40 years of testing. Within the NRI Řež 10 kinds of shelf-stable meat products have been prepared. The meat was cooked, vacuum packed in SiO x-containing pouch, freezed in liquid nitrogen and irradiated with electron beam accelerator. The microbial, chemical, and organoleptic properties have been tested.

Vacuum distillation: vapor filtered-catalytic oxidation water reclamation system utilizing radioisotopes

NASA Technical Reports Server (NTRS)

Honegger, R. J.; Remus, G. A.; Kurg, E. K.

1971-01-01

The development of a functional model water reclamation system is discussed. The system produces potable water by distillation from the urine and respiration-perspiration condensate at the normal rate generated by four men. Basic processes employed are vacuum distillation, vapor filtration, vapor phase catalytic oxidation, and condensation. The system is designed to use four 75-watt isotope heaters for distillation thermal input, and one 45-watt isotope for the catalytic oxidation unit. The system is capable of collecting and storing urine, and provides for stabilizing the urine by chemical pretreatment. The functional model system is designed for operation in a weightless condition with liquid-vapor phase separators for the evaporator still, and centrifugal separators for urine collection and vapor condensation. The system provides for storing and dispensing reclaimed potable water. The system operates in a batch mode for 40 days, with urine residues accumulating in the evaporator. The evaporator still and residue are removed to storage and replaced with a fresh still for the next 40-day period.

Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point

ERIC Educational Resources Information Center

Tellinghuisen, Joel

2010-01-01

Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

(abstract) Undercooling Studies of the Bulk Metallic Glass Forming Zr(sub 41.2)Ti(sub 13.8)Cu(sub 12.5)Ni(sub 10.0)Be(sub 22.5) Alloy During Containerless Electrostatic Levitation Processing

NASA Technical Reports Server (NTRS)

Kim, Y. J.; Busch, R.; Johnson, W. L.; Rulison, A. J.; Rhim, W. K.

1995-01-01

Bulk glass forming metallic alloys have long been desired for technological applications and for investigation into liquid undercooling, solidification processes, and thermophysical properties. A glass forming alloy Zr(sub 41.2)Ti(sub 13.8)Cu(sub 12.5)Ni(sub 10.0)Be(sub 22.5) was used to investigate the thermal treatments affecting undercooling and vitrification. The experiments were performed using the high temperature high vacuum electrostatic levitator at JPL. A sample approximately 3 mm in diameter was melted, superheated, undercooled, and solidified while levitated in high vacuum. The results show that when the sample was held above its melting temperature for a sufficient period of time to dissolve oxides and then cooled faster than a critical cooling rate, it undercooled to the glass transition temperature, T(sub g), and formed a glassy alloy. The required critical cooling rate for metallic glass formation was obtained to be between 0.9 K per second and 1.2 K per second for the 42.4 mg sample.

Load responsive multilayer insulation performance testing

NASA Astrophysics Data System (ADS)

Dye, S.; Kopelove, A.; Mills, G. L.

2014-01-01

Cryogenic insulation designed to operate at various pressures from one atmosphere to vacuum, with high thermal performance and light weight, is needed for cryogenically fueled space launch vehicles and aircraft. Multilayer insulation (MLI) performs well in a high vacuum, but the required vacuum shell for use in the atmosphere is heavy. Spray-on foam insulation (SOFI) is often used in these systems because of its light weight, but can have a higher heat flux than desired. We report on the continued development of Load Responsive Multilayer Insulation (LRMLI), an advanced thermal insulation system that uses dynamic beam discrete spacers that provide high thermal performance both in atmosphere and vacuum. LRMLI consists of layers of thermal radiation barriers separated and supported by micromolded polymer spacers. The spacers have low thermal conductance, and self-support a thin, lightweight vacuum shell that provides internal high vacuum in the insulation. The dynamic load responsive spacers compress to support the external load of a vacuum shell in one atmosphere, and decompress under reduced atmospheric pressure for lower heat leak. Structural load testing was performed on the spacers with various configurations. LRMLI was installed on a 400 liter tank and boil off testing with liquid nitrogen performed at various chamber pressures from one atmosphere to high vacuum. Testing was also performed with an MLI blanket on the outside of the LRMLI.

Combined liquid chromatography-mass spectrometry for trace analysis of pharmaceuticals

NASA Astrophysics Data System (ADS)

Schmidt, Lothar; Danigel, Harald; Jungclas, Hartmut

1982-07-01

A 252Cf-plasma desorption mass spectrometer (PDMS) for the analysis of thin layers from nonvolatile organic samples has been set up to be combined with a liquid chromatograph. A novel interface performs the direct inlet of the liquid sample through a capillary into the vacuum system of the spectrometer. Samples of drugs are periodically collected, transferred to the ion source and analysed using a rotating disk. This on-line sample preparation has been tested for three antiarrhythmic drugs using various solvents and mixtures.

Fiber Bragg grating sensors for real-time monitoring of evacuation process

NASA Astrophysics Data System (ADS)

Guru Prasad, A. S.; Hegde, Gopalkrishna M.; Asokan, S.

2010-03-01

Fiber bragg grating (FBG) sensors have been widely used for number of sensing applications like temperature, pressure, acousto-ultrasonic, static and dynamic strain, refractive index change measurements and so on. Present work demonstrates the use of FBG sensors in in-situ measurement of vacuum process with simultaneous leak detection capability. Experiments were conducted in a bell jar vacuum chamber facilitated with conventional Pirani gauge for vacuum measurement. Three different experiments have been conducted to validate the performance of FBG sensor in monitoring vacuum creating process and air bleeding. The preliminary results of FBG sensors in vacuum monitoring have been compared with that of commercial Pirani gauge sensor. This novel technique offers a simple alternative to conventional method for real time monitoring of evacuation process. Proposed FBG based vacuum sensor has potential applications in vacuum systems involving hazardous environment such as chemical and gas plants, automobile industries, aeronautical establishments and leak monitoring in process industries, where the electrical or MEMS based sensors are prone to explosion and corrosion.

Development of a camera casing suited for cryogenic and vacuum applications

NASA Astrophysics Data System (ADS)

Delaquis, S. C.; Gornea, R.; Janos, S.; Lüthi, M.; von Rohr, Ch Rudolf; Schenk, M.; Vuilleumier, J.-L.

2013-12-01

We report on the design, construction, and operation of a PID temperature controlled and vacuum tight camera casing. The camera casing contains a commercial digital camera and a lighting system. The design of the camera casing and its components are discussed in detail. Pictures taken by this cryo-camera while immersed in argon vapour and liquid nitrogen are presented. The cryo-camera can provide a live view inside cryogenic set-ups and allows to record video.

Temperature dependence of liquid metal embrittlement susceptibility of a modified 9Cr-1Mo steel under low cycle fatigue in lead-bismuth eutectic at 160-450 °C

NASA Astrophysics Data System (ADS)

Gong, Xing; Marmy, Pierre; Qin, Ling; Verlinden, Bert; Wevers, Martine; Seefeldt, Marc

2016-01-01

Low cycle fatigue properties of a 9Cr-1Mo ferritic-martensitic steel (T91) have been tested in a low oxygen concentration (LOC) lead-bismuth eutectic (LBE) environment and in vacuum at 160-450 °C. The results show a clear fatigue endurance "trough" in LOC LBE, while no such a strong temperature dependence of the fatigue endurance is observed when the steel is tested in vacuum. The fractographic observations by means of scanning electron microscopy (SEM) show that ductile microdimples are prevalent on the fracture surfaces of the specimens tested in vacuum, whereas the fracture surfaces produced in LOC LBE at all the temperatures are characterized by quasi-cleavage. Interestingly, using electron backscatter diffraction (EBSD), martensitic laths close to the fatigue crack walls or to the fracture surfaces of the specimens tested in vacuum are found to have transformed into very fine equiaxed subgrains. Nevertheless, such microstructural modifications do not happen to the specimens tested in LOC LBE at 160-450 °C. These interesting microstructural distinctions indicate that liquid metal embrittlement (LME) is able to occur throughout the fatigue crack propagation phase in the full range of the temperatures investigated, i.e. LME is not very sensitive to temperature during the fatigue crack propagation.

Thermographic Analysis of Composite Cobonds on the X-33

NASA Technical Reports Server (NTRS)

Russell, S. S.; Walker, J. L.; Lansing, M. D.

2001-01-01

During the manufacture of the X-33 liquid hydrogen (LH2) Tank 2, a total of 36 reinforcing caps were inspected thermographically. The cured reinforcing sheets of graphite/epoxy were bonded to the tank using a wet cobond process with vacuum bagging and low temperature curing. A foam filler material wedge separated the reinforcing caps from the outer skin of the tank. Manufacturing difficulties caused by a combination of the size of the reinforcing caps and their complex geometry lead to a potential for trapping air in the bond line. An inspection process was desired to ensure that the bond line was free of voids before it had cured so that measures could be taken to rub out the entrapped air or remove the cap and perform additional surface matching. Infrared thermography was used to perform the procure 'wet bond' inspection as well a to document the final 'cured' condition of the caps. The thermal map of the bond line was acquired by heating the cap with either a flash lamp or a set of high intensity quartz lamps and then viewing it during cool down. The inspections were performed through the vacuum bag and voids were characterized by localized hot spots. In order to ensure that the cap had bonded to the tank properly, a post cure 'flash heating' thermographic investigation was performed with the vacuum bag removed. Any regions that had opened up after the preliminary inspection or that were hidden during the bagging operation were marked and filled by drilling small holes in the cap and injecting resin. This process was repeated until all critical sized voids were filled.

Thermographic Analysis of Composite Cobonds on the X-33

NASA Technical Reports Server (NTRS)

Russell, Samuel S.; Walker, James L.; Lansing, Matthew D.; Whitaker, Ann F. (Technical Monitor)

2000-01-01

During the manufacture of the X-33 liquid hydrogen (LH2) Tank 2, a total of thirty-six reinforcing caps were inspected thermographically. The cured reinforcing sheets of graphite/epoxy were bonded to the tank using a wet cobond process with vacuum bagging and low temperature curing. A foam filler material wedge separated the reinforcing caps from the outer skin of the tank. Manufacturing difficulties caused by a combination of the size of the reinforcing caps and their complex geometry lead to a potential for trapping air in the bond line. An inspection process was desired to ensure that the bond line was free of voids before it had cured so that measures could be taken to rub out the entrapped air or remove the cap and perform additional surface matching. Infrared thermography was used to perform the precure "wet bond" inspection as well as to document the final "cured" condition of the caps. The thermal map of the bond line was acquired by heating the cap with either a flash lamp or a set of high intensity quartz lamps and then viewing it during cool down. The inspections were performed through the vacuum bag and voids were characterized by localized hot spots. In order to ensure that the cap had bonded to the tank properly, a post cure "flash heating" thermographic investigation was performed with the vacuum bag removed. Any regions that had opened up after the preliminary inspection or that were hidden during the bagging operation were marked and filled by drilling small holes in the cap and injecting resin. This process was repeated until all critical sized voids were filled.

Variation of the Phytochemical Constituents and Antioxidant Activities of Zingiber officinale var. rubrum Theilade Associated with Different Drying Methods and Polyphenol Oxidase Activity.

PubMed

Ghasemzadeh, Ali; Jaafar, Hawa Z E; Rahmat, Asmah

2016-06-17

The effects of different drying methods (freeze drying, vacuum oven drying, and shade drying) on the phytochemical constituents associated with the antioxidant activities of Z. officinale var. rubrum Theilade were evaluated to determine the optimal drying process for these rhizomes. Total flavonoid content (TFC), total phenolic content (TPC), and polyphenol oxidase (PPO) activity were measured using the spectrophotometric method. Individual phenolic acids and flavonoids, 6- and 8-gingerol and shogaol were identified by ultra-high performance liquid chromatography method. Ferric reducing antioxidant potential (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used for the evaluation of antioxidant activities. The highest reduction in moisture content was observed after freeze drying (82.97%), followed by vacuum oven drying (80.43%) and shade drying (72.65%). The highest TPC, TFC, and 6- and 8-shogaol contents were observed in samples dried by the vacuum oven drying method compared to other drying methods. The highest content of 6- and 8-gingerol was observed after freeze drying, followed by vacuum oven drying and shade drying methods. Fresh samples had the highest PPO activity and lowest content of flavonoid and phenolic acid compounds compared to dried samples. Rhizomes dried by the vacuum oven drying method represent the highest DPPH (52.9%) and FRAP activities (566.5 μM of Fe (II)/g DM), followed by freeze drying (48.3% and 527.1 μM of Fe (II)/g DM, respectively) and shade drying methods (37.64% and 471.8 μM of Fe (II)/g DM, respectively) with IC50 values of 27.2, 29.1, and 34.8 μg/mL, respectively. Negative and significant correlations were observed between PPO and antioxidant activity of rhizomes. Vacuum oven dried rhizomes can be utilized as an ingredient for the development of value-added food products as they contain high contents of phytochemicals with valuable antioxidant potential.

Ejection of Metal Particles into Superfluid 4He by Laser Ablation.

PubMed

Buelna, Xavier; Freund, Adam; Gonzalez, Daniel; Popov, Evgeny; Eloranta, Jussi

2016-10-05

The dynamics following laser ablation of a metal target immersed in superfluid $^4$He is studied by time-resolved shadowgraph photography. The delayed ejection of hot micrometer-sized particles from the target surface into the liquid was indirectly observed by monitoring the formation and growth of gaseous bubbles around the particles. The experimentally determined particle average velocity distribution appears similar as previously measured in vacuum but exhibits a sharp cutoff at the speed of sound of the liquid. The propagation of the subsonic particles terminates in slightly elongated non-spherical gas bubbles residing near the target whereas faster particles reveal an unusual hydrodynamic response of the liquid. Based on the previously established semi-empirical model developed for macroscopic objects, the ejected transonic particles exhibit supercavitating flow to reduce their hydrodynamic drag. Supersonic particles appear to follow a completely different propagation mechanism as they leave discrete and semi-continuous bubble trails in the liquid. The relatively low number density of the observed non-spherical gas bubbles indicates that only large micron-sized particles are visualized in the experiments. Although the unique properties of superfluid helium allow a detailed characterization of these processes, the developed technique can be used to study the hydrodynamic response of any liquid to fast propagating objects on the micrometer-scale.

Apollo Experiment Report: Lunar-Sample Processing in the Lunar Receiving Laboratory High-Vacuum Complex

NASA Technical Reports Server (NTRS)

White, D. R.

1976-01-01

A high-vacuum complex composed of an atmospheric decontamination system, sample-processing chambers, storage chambers, and a transfer system was built to process and examine lunar material while maintaining quarantine status. Problems identified, equipment modifications, and procedure changes made for Apollo 11 and 12 sample processing are presented. The sample processing experiences indicate that only a few operating personnel are required to process the sample efficiently, safely, and rapidly in the high-vacuum complex. The high-vacuum complex was designed to handle the many contingencies, both quarantine and scientific, associated with handling an unknown entity such as the lunar sample. Lunar sample handling necessitated a complex system that could not respond rapidly to changing scientific requirements as the characteristics of the lunar sample were better defined. Although the complex successfully handled the processing of Apollo 11 and 12 lunar samples, the scientific requirement for vacuum samples was deleted after the Apollo 12 mission just as the vacuum system was reaching its full potential.

Superconducting magnetic energy storage apparatus structural support system

DOEpatents

Withers, Gregory J.; Meier, Stephen W.; Walter, Robert J.; Child, Michael D.; DeGraaf, Douglas W.

1992-01-01

A superconducting magnetic energy storage apparatus comprising a cylindrical superconducting coil; a cylindrical coil containment vessel enclosing the coil and adapted to hold a liquid, such as liquefied helium; and a cylindrical vacuum vessel enclosing the coil containment vessel and located in a restraining structure having inner and outer circumferential walls and a floor; the apparatus being provided with horizontal compression members between (1) the coil and the coil containment vessel and (2) between the coil containment vessel and the vacuum vessel, compression bearing members between the vacuum vessel and the restraining structure inner and outer walls, vertical support members (1) between the coil bottom and the coil containment vessel bottom and (2) between the coil containment vessel bottom and the vacuum vessel bottom, and external supports between the vacuum vessel bottom and the restraining structure floor, whereby the loads developed by thermal and magnetic energy changes in the apparatus can be accommodated and the structural integrity of the apparatus be maintained.

Electron-emission characteristics of tungsten alloys: Mee 492. [No data; plasma anode tube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moon, H.M.

A plasma-anode tube was constructed to investigate the electron-emission characteristics for rhenium, 1% thorium tungsten, and 2% thorium tungsten. The tube consists of cathode, anode, cesium reservoir, and three probes. Inside of tube is a rough vacuum by using a Varian liquid-nitrogen-cooled cryovalve and further vacuum by using a Varian absorption pumpt to 4 X IO/sup -5/ pa. The tube was sealed off from the vacuum pump after the cesium ampoule was broken. The entire plasma-anode tube except the cesiunm reservoir was placed in a Blue M Electric Company furnace whose door had been modified to permit viewing of themore » tube.« less

Development of a large low-cost double-chamber vacuum laminator

NASA Technical Reports Server (NTRS)

Burger, D. R.

1983-01-01

A double-chamber vacuum laminator was required to investigate the processing and control of the fabrication of large terrestrial photovoltaic modules, and economic problems arising therefrom. Major design considerations were low cost, process flexibility and the exploration of novel equipment approaches. Spherical end caps for industrial tanks were used for the vacuum chambers. A stepping programmer and adjustable timers were used for process flexibility. New processing options were obtained by use of vacuum sensors. The upper vacuum chamber was provided with a diaphragm support to reduce diaphragm stress. A counterweight was used for handling ease and safety. Heat was supplied by a large electrical strip heater. Thermal isolation and mechanical support were provided inexpensively by a bed of industrial marbles. Operational testing disclosed the need for a differential vacuum gauge and proportional valve. Reprogramming of the process control system was simple and quick.

Molecular dynamics modeling of periodic nanostructuring of metals with a short UV laser pulse under spatial confinement by a water layer

NASA Astrophysics Data System (ADS)

Ivanov, D. S.; Blumenstein, A.; Ihlemann, J.; Simon, P.; Garcia, M. E.; Rethfeld, B.

2017-12-01

The possibility of material surfaces restructuring on the nanoscale due to ultrashort laser pulses has recently found a number of practical applications. It was found experimentally that under spatial confinement due to a liquid layer atop the surface, one can achieve even finer and cleaner structures as compared to that in air or in vacuum. The mechanism of the materials restructuring under the liquid confinement, however, is not clear and its experimental study is limited by the extreme conditions realized during the intense and localized laser energy deposition that takes place on nanometer spatial and picosecond time-scales. In this theoretical work, we suggest a molecular dynamics-based approach that is capable of simulating the processes of periodic nanostructuring with ultrashort UV laser pulse on metals. The theoretical results of the simulations are directly compared with the experimental data on the same spatial and temporal scales.

The Atmospheric Scanning Electron Microscope with open sample space observes dynamic phenomena in liquid or gas.

PubMed

Suga, Mitsuo; Nishiyama, Hidetoshi; Konyuba, Yuji; Iwamatsu, Shinnosuke; Watanabe, Yoshiyuki; Yoshiura, Chie; Ueda, Takumi; Sato, Chikara

2011-12-01

Although conventional electron microscopy (EM) requires samples to be in vacuum, most chemical and physical reactions occur in liquid or gas. The Atmospheric Scanning Electron Microscope (ASEM) can observe dynamic phenomena in liquid or gas under atmospheric pressure in real time. An electron-permeable window made of pressure-resistant 100 nm-thick silicon nitride (SiN) film, set into the bottom of the open ASEM sample dish, allows an electron beam to be projected from underneath the sample. A detector positioned below captures backscattered electrons. Using the ASEM, we observed the radiation-induced self-organization process of particles, as well as phenomena accompanying volume change, including evaporation-induced crystallization. Using the electrochemical ASEM dish, we observed tree-like electrochemical depositions on the cathode. In silver nitrate solution, we observed silver depositions near the cathode forming incidental internal voids. The heated ASEM dish allowed observation of patterns of contrast in melting and solidifying solder. Finally, to demonstrate its applicability for monitoring and control of industrial processes, silver paste and solder paste were examined at high throughput. High resolution, imaging speed, flexibility, adaptability, and ease of use facilitate the observation of previously difficult-to-image phenomena, and make the ASEM applicable to various fields. Copyright © 2011 Elsevier B.V. All rights reserved.

Modeling and Analysis of Chill and Fill Processes for the EDU Tank

NASA Technical Reports Server (NTRS)

Hedayat, A.; Cartagena, W.; Majumdar, A. K.; Leclair, A. C.

2015-01-01

NASA's future missions may require long-term storage and transfer of cryogenic propellants. The Engineering Development Unit (EDU), a NASA in-house effort supported by both Marshall Space Flight Center (MSFC) and Glenn Research Center (GRC), is a Cryogenic Fluid Management (CFM) test article that primarily serves as a manufacturing pathfinder and a risk reduction task for a future CFM payload. The EDU test article, comprises a flight like tank, internal components, insulation, and attachment struts. The EDU is designed to perform integrated passive thermal control performance testing with liquid hydrogen in a space-like vacuum environment. A series of tests, with liquid hydrogen as a testing fluid, was conducted at Test Stand 300 at MSFC during summer of 2014. The objective of this effort was to develop a thermal/fluid model for evaluating the thermodynamic behavior of the EDU tank during the chill and fill processes. Generalized Fluid System Simulation Program (GFSSP), an MSFC in-house general-purpose computer program for flow network analysis, was utilized to model and simulate the chill and fill portion of the testing. The model contained the liquid hydrogen supply source, feed system, EDU tank, and vent system. The modeling description and comparison of model predictions with the test data will be presented in the final paper.

Electrostatic levitation facility optimized for neutron diffraction studies of high temperature liquids at a spallation neutron source

DOE PAGES

Mauro, N. A.; Vogt, A. J.; Derendorf, K. S.; ...

2016-01-01

Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. But, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elasticmore » and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. Furthermore, to demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr 64Ni 36 measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample ( 100 mg).« less

Electrostatic levitation facility optimized for neutron diffraction studies of high temperature liquids at a spallation neutron source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mauro, N. A., E-mail: namauro@noctrl.edu; Vogt, A. J.; Derendorf, K. S.

2016-01-15

Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. However, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elasticmore » and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. To demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr{sub 64}Ni{sub 36} measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample (∼100 mg)« less

Extraction of S- and N-compounds from the mixture of hydrocarbons by ionic liquids as selective solvents.

PubMed

Gabrić, Beata; Sander, Aleksandra; Cvjetko Bubalo, Marina; Macut, Dejan

2013-01-01

Liquid-liquid extraction is an alternative method that can be used for desulfurization and denitrification of gasoline and diesel fuels. Recent approaches employ different ionic liquids as selective solvents, due to their general immiscibility with gasoline and diesel, negligible vapor pressure, and high selectivity to sulfur- and nitrogen-containing compounds. For that reason, five imidazolium-based ionic liquids and one pyridinium-based ionic liquid were selected for extraction of thiophene, dibenzothiophene, and pyridine from two model solutions. The influences of hydrodynamic conditions, mass ratio, and number of stages were investigated. Increasing the mass ratio of ionic liquid/model fuel and multistage extraction promotes the desulfurization and denitrification abilities of the examined ionic liquids. All selected ionic liquids can be reused and regenerated by means of vacuum evaporation.

Extraction of S- and N-Compounds from the Mixture of Hydrocarbons by Ionic Liquids as Selective Solvents

PubMed Central

Gabrić, Beata; Sander, Aleksandra; Cvjetko Bubalo, Marina; Macut, Dejan

2013-01-01

Liquid-liquid extraction is an alternative method that can be used for desulfurization and denitrification of gasoline and diesel fuels. Recent approaches employ different ionic liquids as selective solvents, due to their general immiscibility with gasoline and diesel, negligible vapor pressure, and high selectivity to sulfur- and nitrogen-containing compounds. For that reason, five imidazolium-based ionic liquids and one pyridinium-based ionic liquid were selected for extraction of thiophene, dibenzothiophene, and pyridine from two model solutions. The influences of hydrodynamic conditions, mass ratio, and number of stages were investigated. Increasing the mass ratio of ionic liquid/model fuel and multistage extraction promotes the desulfurization and denitrification abilities of the examined ionic liquids. All selected ionic liquids can be reused and regenerated by means of vacuum evaporation. PMID:23843736

Vacuum pump apparatus

DOEpatents

Batzer, Thomas H.; Call, Wayne R.

1985-01-01

An improved cryopumping apparatus which comprises a cryopumping space which may be alternately opened and closed from the surrounding area by moveable panels, trubular cryopanels within said cryopumping space through which a coolant such as liquid helium may be passed, and an apparatus for spraying liquid argon onto said cylindrical cryopanels in order to enhance the cryogenic entrapment of such low-z ions, atoms, and molecules as hydrogen and helium.

Diffusely Reflecting Paints Containing TFE

NASA Technical Reports Server (NTRS)

Shai, M. C.; Schutt, J. B.

1985-01-01

Highly reflective, diffused coatings developed by incorporating polytetrafluoroethylene (TFE) pigment with alcohol-soluble binders. Alcohol and binder mixed together in blender before adding TFE. TFE preferably outgassed in mechanical-pump vacuum for typical interval of 4 hours before adding to liquid. Like wetting agent, vacuum treatment helps to prevent clumping of TFE and eases dispersion throughout mixture. Mixture blended for 3 to 5 minutes before used. Coatings useful on reflectance-standard surfaces for calibrating radiometric instruments in both laboratory and field. Paints washable and usable as optical reference surfaces.

Inexpensive cryogenic insulation replaces vacuum jacketed line

NASA Technical Reports Server (NTRS)

Fuchs, C. E.

1967-01-01

Commercially available aluminized Mylar, cork and fiber glass form a multilayered sealed system and provide rugged and economical field installed insulation for cryogenic /liquid nitrogen or oxygen/ pipe lines in an exposed environment.

Development of a Contingency Capillary Wastewater Management Device

NASA Technical Reports Server (NTRS)

Thomas, Evan A.

2010-01-01

The Personal Body .Attached Liquid Liquidator (PBALL) is conceived as a passive, capillary driven contingency wastewater disposal device. In this contingency scenario, the airflow system on the NASA Crew Exploration Vehicle (CEV) is assumed to have failed, leaving only passive hardware and vacuum vent to dispose of the wastewater. To meet these needs, the PBALL was conceived to rely on capillary action and urine wetting design considerations. The PBALL is designed to accommodate a range of wetting conditions, from 0deg < (theta)adv approx. 90deg, be adaptable for both male and female use, collect and retain up to a liter of urine, minimize splash-back, and allow continuous drain of the wastewater to vacuum while minimizing cabin air loss. A sub-scale PBALL test article was demonstrated on NASA's reduced gravity aircraft in April, 2010.

Drive-amplitude-modulation atomic force microscopy: From vacuum to liquids

PubMed Central

Jaafar, Miriam; Cuenca, Mariano; Melcher, John; Raman, Arvind

2012-01-01

Summary We introduce drive-amplitude-modulation atomic force microscopy as a dynamic mode with outstanding performance in all environments from vacuum to liquids. As with frequency modulation, the new mode follows a feedback scheme with two nested loops: The first keeps the cantilever oscillation amplitude constant by regulating the driving force, and the second uses the driving force as the feedback variable for topography. Additionally, a phase-locked loop can be used as a parallel feedback allowing separation of the conservative and nonconservative interactions. We describe the basis of this mode and present some examples of its performance in three different environments. Drive-amplutide modulation is a very stable, intuitive and easy to use mode that is free of the feedback instability associated with the noncontact-to-contact transition that occurs in the frequency-modulation mode. PMID:22563531

Rapid microfluidic mixing and liquid jets for studying biomolecular chemical dynamics

NASA Astrophysics Data System (ADS)

Langley, Daniel; Abbey, Brian

2018-01-01

X-ray Free-Electron Lasers (XFELs) offer a unique opportunity to study the structural dynamics of proteins on a femtosecond time-scale. To realize the full potential of XFEL sources for studying time-resolved biomolecular processes however, requires the optimization and development of devices that can both act as a trigger and a delivery mechanism for the system of interest. Here we present numerical simulations and actual devices exploring the conditions required for the development of successful mixing and injection devices for tracking the molecular dynamics of proteins in solution on micro to nanosecond timescales using XFELs. The mechanism for combining reagents employs a threefold combination of pico-liter volumes, lamination and serpentine mixing. Focusing and delivering the sample in solution is achieved using the Gas Dynamic Virtual Nozzle (GDVN), which was specifically developed to produce a micrometer diameter, in-vacuum liquid jet. We explore the influence of parameters such as flow rate and gas pressure on the mixing time and jet stability, and explore the formation of rapid homogeneously mixed jets for `mix-and-inject' liquid scattering experiments at Synchrotron and XFEL facilities.

Investigation of Physically and Chemically Ionic Liquid Confinement in Nanoporous Materials by a Combination of SANS, Contrast-Matching SANS, XRD and Nitrogen Adsorption

NASA Astrophysics Data System (ADS)

Romanos, G. E.; Stefanopoulos, K. L.; Vangeli, O. C.; Mergia, K.; Beltsios, K. G.; Kanellopoulos, N. K.; Lairez, D.

2012-02-01

In the present study, [bmim][PF6] ionic liquid (IL) was introduced into the pores of two ordered mesoporous silicas (MCM-41 and SBA-15) having different pore sizes by means of two different processes: a) with physical imbibition from a methanol solution under high vacuum and b) by chemically immobilising the IL with silanisation of the pore surface followed by reaction with butyl-methyl imidazolium chloride and anion exchange with PF6, the process termed as the "grafting to" method. Both the extent of IL entrapment and the structural properties of the IL phase under confinement were investigated by SANS, contrast-matching SANS, XRD and nitrogen adsorption measurements. The results show that the pores of chemically prepared samples are not totally filled by IL and also suggest for ordering of the silylated IL phase. On the other hand, the physically prepared samples are almost or totally filled with IL whereas no evidence for ordering of the confined IL phase was observed.

Effect of vacuum roasting on acrylamide formation and reduction in coffee beans.

PubMed

Anese, Monica; Nicoli, Maria Cristina; Verardo, Giancarlo; Munari, Marina; Mirolo, Giorgio; Bortolomeazzi, Renzo

2014-02-15

Coffea arabica beans were roasted in an oven at 200 °C for increasing lengths of time under vacuum (i.e. 0.15 kPa). The samples were then analysed for colour, weight loss, acrylamide concentration and sensory properties. Data were compared with those obtained from coffee roasted at atmospheric pressure (i.e. conventional roasting), as well as at atmospheric pressure for 10 min followed by vacuum treatment (0.15 kPa; i.e. conventional-vacuum roasting). To compare the different treatments, weight loss, colour and acrylamide changes were expressed as a function of the thermal effect received by the coffee beans during the different roasting processes. Vacuum-processed coffee with medium roast degree had approximately 50% less acrylamide than its conventionally roasted counterpart. It was inferred that the low pressure generated inside the oven during the vacuum process exerted a stripping effect preventing acrylamide from being accumulated. Vacuum-processed coffee showed similar colour and sensory properties to conventionally roasted coffee. Copyright © 2013 Elsevier Ltd. All rights reserved.

High resolution imaging of the dynamics of nanoparticles in/on liquids

NASA Astrophysics Data System (ADS)

Kim, Paul; Ribbe, Alexander; Russell, Thomas; Hoagland, David

Electron microscopy for the study of nanoscale structure and dynamics in solvated soft materials has only recently been proposed, and since this technique requires high vacuum, significant challenges must be confronted. Specimens can be encapsulated in vacuum-sealed devices for TEM but this approach is not without difficulties, including beam damage, cumbersome specimen handling, and propensity for wall artifacts. Here, we report an alternative SEM approach, obviating need for a liquid cell by exploiting the nonvolatility of ionic liquids, which is illustrated by visualizations of nanoscale dynamics for two solvated systems, dispersed nanospheres and nanorods in/on thin, free-standing IL films. The translational and rotational Brownian of these nanoparticles were quantitatively tracked. In ultra-thin films, a striking and unanticipated dynamical pairing of the nanospheres was observed, manifesting a balance of capillary and hydrodynamic interactions. Concentrated nanorods were seen to assemble into finite stacks that could be tracked over their entire lifetimes. Broadly applicable to solvated soft nanoscopic materials, the new imaging protocol offers a breakthrough in the study of their structure and dynamics.

Particle Collection Efficiency of a Lens-Liquid Filtration System

NASA Astrophysics Data System (ADS)

Wong, Ross Y. M.; Ng, Moses L. F.; Chao, Christopher Y. H.; Li, Z. G.

2011-09-01

Clinical and epidemiological studies have shown that indoor air quality has substantial impact on the health of building occupants [1]. Possible sources of indoor air contamination include hazardous gases as well as particulate matters (PMs) [2]. Experimental studies show that the size distribution of PMs in indoor air ranges from tens of nanometers to a few hundreds of micrometers [3]. Vacuum cleaners can be used as a major tool to collect PMs from floor/carpets, which are the main sources of indoor PMs. However, the particle collection efficiency of typical cyclonic filters in the vacuums drops significantly for particles of diameter below 10 μm. In this work, we propose a lens-liquid filtration system (see Figure 1), where the flow channel is formed by a liquid free surface and a planar plate with fin/lens structures. Computational fluid dynamics simulations are performed by using FLUENT to optimize the structure of the proposed system toward high particle collection efficiency and satisfactory pressure drop. Numerical simulations show that the system can collect 250 nm diameter particles with collection efficiency of 50%.

Numerical study on the thermal management system of a liquid metal battery module

NASA Astrophysics Data System (ADS)

Guo, Zhenlin; Xu, Cheng; Li, Wei; Zhu, Fangfang; Li, Haomiao; Wang, Kangli; Cheng, Shijie; Jiang, Kai

2018-07-01

Liquid metal battery (LMB), with three-liquid-layer structure and high operating temperature (300-700 °C), is a newly emerging technology for large scale energy storage applications. A thermal management system is critical to achieve satisfied LMB performance and extend the life of batteries. In this work, an improved coupling model composing of a 3D heat-transfer model and a 1D electrochemical model is developed for the thermal analysis of a Li||Sb-Sn LMBs module (5.5 kWh). Key results including transient values, the contribution ratio of heat sources, temperature homogeneity and distribution, as well as the energy efficiency of the battery module, are presented. Based on the coupling model, the changeable-power-heating mode, sand filling material and vacuum insulation are further proposed to achieve the high energy efficiency and optimal performance of the LMBs module. Moreover, the LMBs module can achieve "self-heating" when operated at 0.2 C charge/discharge, under the vacuum insulation (0.01 W m-1 K-1 thermal conductivity, 100 mm thickness), requiring no external heating to keep the batteries at operating temperature.

Method for sequentially processing a multi-level interconnect circuit in a vacuum chamber

NASA Technical Reports Server (NTRS)

Routh, D. E.; Sharma, G. C. (Inventor)

1984-01-01

An apparatus is disclosed which includes a vacuum system having a vacuum chamber in which wafers are processed on rotating turntables. The vacuum chamber is provided with an RF sputtering system and a dc magnetron sputtering system. A gas inlet introduces various gases to the vacuum chamber and creates various gas plasma during the sputtering steps. The rotating turntables insure that the respective wafers are present under the sputtering guns for an average amount of time such that consistency in sputtering and deposition is achieved. By continuous and sequential processing of the wafers in a common vacuum chamber without removal, the adverse affects of exposure to atmospheric conditions are eliminated providing higher quality circuit contacts and functional device.

Method for sequentially processing a multi-level interconnect circuit in a vacuum chamber

NASA Technical Reports Server (NTRS)

Routh, D. E.; Sharma, G. C. (Inventor)

1982-01-01

The processing of wafer devices to form multilevel interconnects for microelectronic circuits is described. The method is directed to performing the sequential steps of etching the via, removing the photo resist pattern, back sputtering the entire wafer surface and depositing the next layer of interconnect material under common vacuum conditions without exposure to atmospheric conditions. Apparatus for performing the method includes a vacuum system having a vacuum chamber in which wafers are processed on rotating turntables. The vacuum chamber is provided with an RF sputtering system and a DC magnetron sputtering system. A gas inlet is provided in the chamber for the introduction of various gases to the vacuum chamber and the creation of various gas plasma during the sputtering steps.

Load responsive multilayer insulation performance testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dye, S.; Kopelove, A.; Mills, G. L.

Cryogenic insulation designed to operate at various pressures from one atmosphere to vacuum, with high thermal performance and light weight, is needed for cryogenically fueled space launch vehicles and aircraft. Multilayer insulation (MLI) performs well in a high vacuum, but the required vacuum shell for use in the atmosphere is heavy. Spray-on foam insulation (SOFI) is often used in these systems because of its light weight, but can have a higher heat flux than desired. We report on the continued development of Load Responsive Multilayer Insulation (LRMLI), an advanced thermal insulation system that uses dynamic beam discrete spacers that providemore » high thermal performance both in atmosphere and vacuum. LRMLI consists of layers of thermal radiation barriers separated and supported by micromolded polymer spacers. The spacers have low thermal conductance, and self-support a thin, lightweight vacuum shell that provides internal high vacuum in the insulation. The dynamic load responsive spacers compress to support the external load of a vacuum shell in one atmosphere, and decompress under reduced atmospheric pressure for lower heat leak. Structural load testing was performed on the spacers with various configurations. LRMLI was installed on a 400 liter tank and boil off testing with liquid nitrogen performed at various chamber pressures from one atmosphere to high vacuum. Testing was also performed with an MLI blanket on the outside of the LRMLI.« less

Vacuum-driven power-free microfluidics utilizing the gas solubility or permeability of polydimethylsiloxane (PDMS).

PubMed

Xu, Linfeng; Lee, Hun; Jetta, Deekshitha; Oh, Kwang W

2015-10-21

Suitable pumping methods for flow control remain a major technical hurdle in the path of biomedical microfluidic systems for point-of-care (POC) diagnostics. A vacuum-driven power-free micropumping method provides a promising solution to such a challenge. In this review, we focus on vacuum-driven power-free microfluidics based on the gas solubility or permeability of polydimethylsiloxane (PDMS); degassed PDMS can restore air inside itself due to its high gas solubility or gas permeable nature. PDMS allows the transfer of air into a vacuum through it due to its high gas permeability. Therefore, it is possible to store or transfer air into or through the gas soluble or permeable PDMS in order to withdraw liquids into the embedded dead-end microfluidic channels. This article provides a comprehensive look at the physics of the gas solubility and permeability of PDMS, a systematic review of different types of vacuum-driven power-free microfluidics, and guidelines for designing solubility-based or permeability-based PDMS devices, alongside existing applications. Advanced topics and the outlook in using micropumping that utilizes the gas solubility or permeability of PDMS will be also discussed. We strongly recommend that microfluidics and lab-on-chip (LOC) communities harness vacuum energy to develop smart vacuum-driven microfluidic systems.

Structural and phase transformations during ball milling of titanium in medium of liquid hydrocarbons

NASA Astrophysics Data System (ADS)

Dorofeev, G. A.; Lubnin, A. N.; Lad'yanov, V. I.; Mukhgalin, V. V.; Puskkarev, B. E.

2014-02-01

It has been shown using X-ray diffraction, scanning electron microscopy, and chemical analysis that, upon ball milling of α-titanium in liquid organic media (toluene and n-heptane), a nanocrystalline fcc phase is formed that is a metastable carbohydride Ti(C,H) deficient in hydrogen and carbon compared to stable carbohydrides. The dimensions of powder particles after milling in toluene and n-heptane differ substantially (are 5-10 and 20-30 μm, respectively. It has been shown that the kinetics of the formation of Ti(C,H) is independent of the milling medium. The atomic ratios H/C in the products of mechanosynthesis agree well with those corresponding to the employed organic media, i.e., H/C = 1.1 for toluene and 2.3 for n-heptane. A solid-liquid mechanism of mechanosynthesis is suggested, which includes repeated processes of particle fracturing with the formation of fresh surfaces, adsorption of liquid hydrocarbons on these surfaces, and subsequent cold welding of the newly formed particles. It is assumed that the formation of the fcc phase in the process of milling is connected with the generation of stacking faults in α-Ti. Upon annealing at 550°C, the fcc phase decomposes with the formation of stable titanium carbide TiC (annealing in a vacuum) or stable titanium carbohydride and a β-Ti(H) solid solution (annealing in argon) with a partial reverse transformation Ti(C,H) → α-Ti in both cases.

Beamline Electrostatic Levitator (BESL) for in-situ High Energy K-Ray Diffraction Studies of Levitated Solids and Liquids at High Temperature

NASA Technical Reports Server (NTRS)

Gangopadhyay, A. K.; Lee, G. W.; Kelton, K. F.; Rogers, J. R.; Goldman, A. I.; Robinson, D. S.; Rathz, T. J.; Hyers, R. W.

2005-01-01

Determinations of the phase formation sequence, the crystal structures and the thermodynamic properties of materials at high temperatures are difficult because of contamination from the sample container and environment. Containerless processing techniques, such as electrostatic (ESL), electromagnetic (EML), aerodynamic, and acoustic levitation, are most suitable these studies. An adaptation of ESL for in-situ structural studies of a wide range of materials, including metals, semiconductors, insulators using high energy (125 keV) synchrotron x-rays is described here. This beamline ESL (BESL) allows the in-situ determination of the atomic structures of equilibrium solid and liquid phases, including undercooled liquids, as well as real-time studies of solid-solid and liquid-solid phase transformations. The use of image plate (MAR345) or GE-Angio detectors enables fast (30 ms - 1s) acquisition of complete diffraction patterns over a wide q-range (4 - 140/mm). The wide temperature range (300 - 2500 K), containerless processing under high vacuum (10(exp -7) - 10(exp -8) torr), and fast data acquisition, make BESL particularly suitable for phase diagram studies of high temperature materials. An additional, critically important, feature of BESL is the ability to also make simultaneous measurement of a host of thermo-physical properties, including the specific heat, enthalpy of transformation, solidus and liquidus temperatures, density, viscosity, and surface tension; all on the same sample and simultaneous with the structural measurements.

46 CFR 154.804 - Vacuum protection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... suction of cargo liquid or vapor from the cargo tank and secures any refrigeration of that tank at or... return to the cargo tanks; (ii) By operation of the cargo refrigeration system; or (iii) By drawing off...

46 CFR 154.804 - Vacuum protection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... suction of cargo liquid or vapor from the cargo tank and secures any refrigeration of that tank at or... return to the cargo tanks; (ii) By operation of the cargo refrigeration system; or (iii) By drawing off...

Design of a Pilot Plant for Vacuum Infusion of High Lipoidal Liquids into Dried Foods

DTIC Science & Technology

1988-07-01

on a conveyor belt equipped with a chiller hood. /". 20 DISTRIBUTION’AVAILABILITY OF ABSTRACT SUNCLASSlFlEn’VL’V’S:» Q jwj AS RB" U DtiC US...design is an optimization of design criteria, shown in Figure I. In addition to the basic design criteria, the equipment must operate within a...the desired setpoint . 2.2 Lipoidal Liquid Systems; The lipoidal liquid is provided at the proper conditions to the immersion dish from an

Robust Low Cost Liquid Rocket Combustion Chamber by Advanced Vacuum Plasma Process

NASA Technical Reports Server (NTRS)

Holmes, Richard; Elam, Sandra; Ellis, David L.; McKechnie, Timothy; Hickman, Robert; Rose, M. Franklin (Technical Monitor)

2001-01-01

Next-generation, regeneratively cooled rocket engines will require materials that can withstand high temperatures while retaining high thermal conductivity. Fabrication techniques must be cost efficient so that engine components can be manufactured within the constraints of shrinking budgets. Three technologies have been combined to produce an advanced liquid rocket engine combustion chamber at NASA-Marshall Space Flight Center (MSFC) using relatively low-cost, vacuum-plasma-spray (VPS) techniques. Copper alloy NARloy-Z was replaced with a new high performance Cu-8Cr-4Nb alloy developed by NASA-Glenn Research Center (GRC), which possesses excellent high-temperature strength, creep resistance, and low cycle fatigue behavior combined with exceptional thermal stability. Functional gradient technology, developed building composite cartridges for space furnaces was incorporated to add oxidation resistant and thermal barrier coatings as an integral part of the hot wall of the liner during the VPS process. NiCrAlY, utilized to produce durable protective coating for the space shuttle high pressure fuel turbopump (BPFTP) turbine blades, was used as the functional gradient material coating (FGM). The FGM not only serves as a protection from oxidation or blanching, the main cause of engine failure, but also serves as a thermal barrier because of its lower thermal conductivity, reducing the temperature of the combustion liner 200 F, from 1000 F to 800 F producing longer life. The objective of this program was to develop and demonstrate the technology to fabricate high-performance, robust, inexpensive combustion chambers for advanced propulsion systems (such as Lockheed-Martin's VentureStar and NASA's Reusable Launch Vehicle, RLV) using the low-cost VPS process. VPS formed combustion chamber test articles have been formed with the FGM hot wall built in and hot fire tested, demonstrating for the first time a coating that will remain intact through the hot firing test, and with no apparent wear. Material physical properties and the hot firing tests are reviewed.

Applied in situ product recovery in ABE fermentation.

PubMed

Outram, Victoria; Lalander, Carl-Axel; Lee, Jonathan G M; Davies, E Timothy; Harvey, Adam P

2017-05-01

The production of biobutanol is hindered by the product's toxicity to the bacteria, which limits the productivity of the process. In situ product recovery of butanol can improve the productivity by removing the source of inhibition. This paper reviews in situ product recovery techniques applied to the acetone butanol ethanol fermentation in a stirred tank reactor. Methods of in situ recovery include gas stripping, vacuum fermentation, pervaporation, liquid-liquid extraction, perstraction, and adsorption, all of which have been investigated for the acetone, butanol, and ethanol fermentation. All techniques have shown an improvement in substrate utilization, yield, productivity or both. Different fermentation modes favored different techniques. For batch processing gas stripping and pervaporation were most favorable, but in fed-batch fermentations gas stripping and adsorption were most promising. During continuous processing perstraction appeared to offer the best improvement. The use of hybrid techniques can increase the final product concentration beyond that of single-stage techniques. Therefore, the selection of an in situ product recovery technique would require comparable information on the energy demand and economics of the process. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:563-579, 2017. © 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers.

Embossed Teflon AF Laminate Membrane Microfluidic Diaphragm Valves

NASA Technical Reports Server (NTRS)

Willis, Peter; Hunt, Brian; White,Victor; Grunthaner, Frank

2008-01-01

A microfluidic system has been designed to survive spaceflight and to function autonomously on the Martian surface. It manipulates microscopic quantities of liquid water and performs chemical analyses on these samples to assay for the presence of molecules associated with past or present living processes. This technology lies at the core of the Urey Instrument, which is scheduled for inclusion on the Pasteur Payload of the ESA ExoMars rover mission in 2013. Fabrication processes have been developed to make the microfabricated Teflon-AF microfluidic diaphragm pumps capable of surviving extreme temperature excursions before and after exposure to liquid water. Two glass wafers are etched with features and a continuous Teflon membrane is sandwiched between them (see figure). Single valves are constructed using this geometry. The microfabricated devices are then post processed by heating the assembled device while applying pneumatic pressure to force the Teflon diaphragm against the valve seat while it is softened. After cooling the device, the embossed membrane retains this new shape. This solves previous problems with bubble introduction into the fluid flow where deformations of the membrane at the valve seat occurred during device bonding at elevated temperatures (100-150 C). The use of laminated membranes containing commercial Teflon AF 2400 sheet sandwiched between spun Teflon AF 1600 layers performed best, and were less gas permeable than Teflon AF 1600 membranes on their own. Spinning Teflon AF 1600 solution (6 percent in FLOURINERT(Registered TradeMark) FC40 solvent, 3M Company) at 500 rpm for 1.5 seconds, followed by 1,000 rpm for 3 seconds onto Borofloat glass wafers, results in a 10-micron-thick film of extremely smooth Teflon AF. This spinning process is repeated several times on flat, blank, glass wafers in order to gradually build a thick, smooth membrane. After running this process at least five times, the wafer and Teflon coating are heated under vacuum at 220 C for one hour in order to drive off any residual solvent present in the composite film. After this, a second blank, glass wafer is brought down from above and the stack is held under vacuum at 3 atm mechanical pressure for ten 10 hours.

By-products of electrochemical synthesis of suberic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shirobokova, O.I.; Adamov, A.A.; Freidlin, G.N.

By-products of the electrochemical synthesis of dimethyl suberate from glutaric anhydride were studied. This is isolated by thermal dehydration of a mixture of lower dicarboxylic acids that are wastes from the production of adipic acid. To isolate the by-products, they used the methods of vacuum rectification and preparative gas-liquid chromatography, and for their identification, PMR, IR spectroscopy, gas-liquid chromatography, and other known physicochemical methods of investigation.

Solar Simulation for the CREST Preflight Thermal-Vacuum Test at B-2

NASA Technical Reports Server (NTRS)

Ziemke, Robert A.

2013-01-01

In June 2011, the multi-university sponsored Cosmic Ray Electron Synchrotron Telescope (CREST) has undergone thermal-vacuum qualification testing at the NASA Glenn Research Center (GRC), Plum Brook Station, Sandusky, Ohio. The testing was performed in the B- 2 Space Propulsion Facility vacuum chamber. The CREST was later flown over the Antarctic region as the payload of a stratospheric balloon. Solar simulation was provided by a system of planar infrared lamp arrays specifically designed for CREST. The lamp arrays, in conjunction with a liquid-nitrogen-cooled cryoshroud, achieved the required thermal conditions for the qualification tests. This report focuses on the design and analysis of the planar arrays based on first principles. Computational spreadsheets are included in the report.

Novel Kombucha Beverage from Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum, with Antibacterial and Antioxidant Effects.

PubMed

Sknepnek, Aleksandra; Pantić, Milena; Matijašević, Danka; Miletić, Dunja; Lević, Steva; Nedović, Viktor; Niksic, Miomir

2018-01-01

Kombucha is a nonalcoholic beverage traditionally made by fermenting black tea using a combination of yeast and acetic acid bacteria (AAB) cultures. Ganoderma lucidum hot water extract (HWE) was used-to our knowledge for the first time-to prepare a novel, health-promoting kombucha product. During the 11-day fermentation, pH, total acidity, and the numbers of yeasts and AAB were monitored. It was found that sweetened G. lucidum HWE was a good medium for yeast and AAB growth. The desired acidity for the beverage was reached on the second day (3 g/L) of the fermentation process; the maximum established acidity was 22.8 ± 0.42 g/L. Fourier transform infrared analysis revealed that the vacuum-dried beverage is a mixture of various compounds such as polysaccharides, phenols, proteins, and lipids. Total phenolic content of the liquid sample was 4.91 ± 0.2338 mg gallic acid equivalents/g, whereas the vacuum-dried sample had a smaller amount of phenolics (2.107 ± 0.228 mg gallic acid equivalents/g). Established half-maximal effective concentrations for DPPH scavenging activity and reducing power were 22.8 ± 0.17 and 10.61 ± 0.34 mg/mL, respectively. The antibacterial testing revealed that activity does not originate solely from synthesized acetic acid. The liquid G. lucidum beverage was the most effective against the tested bacteria, with the lowest minimum inhibitory concentration (0.04 mg/mL) against Staphylococcus epidermidis and Rhodococcus equi, and a minimum bactericidal concentration (0.16 mg/mL) against Bacillus spizizenii, B. cereus, and R. equi. The vacuum-dried sample was less effective, with the lowest minimum bactericidal concentration against the Gram-positive bacteria R. equi (1.875 mg/mL) and against the Gram-negative bacteria Proteus hauseri (30 mg/mL).

Design study for a liquid metal slip ring solar array orientation mechanism

NASA Technical Reports Server (NTRS)

Clark, R. B.

1972-01-01

The design of a single axis orientation mechanism for solar arrays on high power synchronous satellites is studied primarily with respect to providing 116 liquid metal slip rings for reduced friction and improved electrical characteristics. Designs and tradeoff studies for the slip rings and other components are presented. An assembly containing 33 slip rings of three design approaches was designed, fabricated, and vacuum tested to 30 amperes and 30,000 volts. Containment of the liquid metal gallium in large diameter slip rings was difficult. A design approach is presented which is expected to provide improved retention of the liquid metal.

Waste Management System overview for future spacecraft.

NASA Technical Reports Server (NTRS)

Ingelfinger, A. L.; Murray, R. W.

1973-01-01

Waste Management Systems (WMS) for post Apollo spacecraft will be significantly more sophisticated and earthlike in user procedures. Some of the features of the advanced WMS will be accommodation of both males and females, automatic operation, either tissue wipe or anal wash, measurement and sampling of urine, feces and vomitus for medical analysis, water recovery, and solids disposal. This paper presents an overview of the major problems of and approaches to waste management for future spacecraft. Some of the processes discussed are liquid/gas separation, the Dry-John, the Hydro-John, automated sampling, vapor compression distillation, vacuum distillation-catalytic oxidation, incineration, and the integration of the above into complete systems.

Mechanical properties and production quality of hand-layup and vacuum infusion processed hybrid composite materials for GFRP marine structures

NASA Astrophysics Data System (ADS)

Kim, Sang-Young; Shim, Chun Sik; Sturtevant, Caleb; Kim, Dave (Dae-Wook); Song, Ha Cheol

2014-09-01

Glass Fiber Reinforced Plastic (GFRP) structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties

Method and apparatus for scientific analysis under low temperature vacuum conditions

DOEpatents

Winefordner, James D.; Jones, Bradley T.

1990-01-01

A method and apparatus for scientific analysis of a sample under low temperature vacuum conditions uses a vacuum chamber with a conveyor belt disposed therein. One end of the conveyor belt is a cool end in thermal contact with the cold stage of a refrigerator, whereas the other end of the conveyor belt is a warm end spaced from the refrigerator. A septum allows injection of a sample into the vacuum chamber on top of the conveyor belt for spectroscopic or other analysis. The sample freezes on the conveyor belt at the cold end. One or more windows in the vacuum chamber housing allow spectroscopic analysis of the sample. Following the spectroscopic analysis, the conveyor belt may be moved such that the sample moves toward the warm end of the conveyor belt where upon it evaporates, thereby cleaning the conveyor belt. Instead of injecting the sample by way of a septum and use of a syringe and needle, the present device may be used in series with capillary-column gas chromatography or micro-bore high performance liquid chromatography.

46 CFR 153.602 - Special requirements for cargoes reactive with water.

Code of Federal Regulations, 2012 CFR

2012-10-01

... DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design.... When Table 1 refers to this section, the air inlet to the pressure-vacuum valve for the cargo tank must...

46 CFR 153.602 - Special requirements for cargoes reactive with water.

Code of Federal Regulations, 2011 CFR

2011-10-01

... DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design.... When Table 1 refers to this section, the air inlet to the pressure-vacuum valve for the cargo tank must...

46 CFR 153.1600 - Equipment required for conducting the stripping quantity test.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS... container: (1) A wet vacuum. (2) A positive displacement pump. (3) An eductor with an air/water separator in...

46 CFR 153.602 - Special requirements for cargoes reactive with water.

Code of Federal Regulations, 2013 CFR

2013-10-01

... DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design.... When Table 1 refers to this section, the air inlet to the pressure-vacuum valve for the cargo tank must...

46 CFR 153.1600 - Equipment required for conducting the stripping quantity test.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS... container: (1) A wet vacuum. (2) A positive displacement pump. (3) An eductor with an air/water separator in...

46 CFR 153.1600 - Equipment required for conducting the stripping quantity test.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS... container: (1) A wet vacuum. (2) A positive displacement pump. (3) An eductor with an air/water separator in...

46 CFR 153.1600 - Equipment required for conducting the stripping quantity test.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS... container: (1) A wet vacuum. (2) A positive displacement pump. (3) An eductor with an air/water separator in...

Excavationless Exterior Foundation Insulation Field Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schirber, T.; Mosiman, G.; Ojczyk, C.

Building science research supports installing exterior (soil side) foundation insulation as the optimal method to enhance the hygrothermal performance of new homes. With exterior foundation insulation, water management strategies are maximized while insulating the basement space and ensuring a more even temperature at the foundation wall. However, such an approach can be very costly and disruptive when applied to an existing home, requiring deep excavation around the entire house. The NorthernSTAR Building America Partnership team implemented an innovative, minimally invasive foundation insulation upgrade technique on an existing home. The approach consisted of using hydrovac excavation technology combined with liquid insulatingmore » foam. The team was able to excavate a continuous 4 inches wide by 4 feet to 5 feet deep trench around the entire house, 128 linear feet, except for one small part under the stoop that was obstructed with concrete debris. The combination pressure washer and vacuum extraction technology also enabled the elimination of large trenches and soil stockpiles normally produced by backhoe excavation. The resulting trench was filled with liquid insulating foam, which also served as a water-control layer of the assembly. The insulation was brought above grade using a liquid foam/rigid foam hybrid system and terminated at the top of the rim joist. Cost savings over the traditional excavation process ranged from 23% to 50%. The excavationless process could result in even greater savings since replacement of building structures, exterior features, utility meters, and landscaping would be minimal or non-existent in an excavationless process.« less

Variable-temperature cryogenic trap for the separation of gas mixtures

NASA Technical Reports Server (NTRS)

Des Marais, D. J.

1978-01-01

The paper describes a continuous variable-temperature U-shaped cold trap which can both purify vacuum-line combustion products for subsequent stable isotopic analysis and isolate the methane and ethane constituents of natural gases. The canister containing the trap is submerged in liquid nitrogen, and, as the gas cools, the gas mixture components condense sequentially according to their relative vapor pressures. After the about 12 min required for the bottom of the trap to reach the liquid-nitrogen temperature, passage of electric current through the resistance wire wrapped around the tubing covering the U-trap permits distillation of successive gas components at optimal temperatures. Data on the separation achieved for two mixtures, the first being typical vacuum-line combustion products of geochemical samples such as rocks and the second being natural gas, are presented, and the thermal behavior and power consumption are reported.

High Performance Variable Emittance Devices for Spacecraft Application Based on Conducting Polymers Coupled with Ionic Liquids

NASA Astrophysics Data System (ADS)

Chandrasekhar, Prasanna; Zay, Brian J.; Barbolt, Scott; Werner, Robert; Birur, Gajanana C.; Paris, Anthony

2009-03-01

This contribution describes the fabrication, function and performance of thin-film variable emittance electrochromic skins fabricated using poly(aniline) as the conducting polymer (CP), a long-chain polymeric dopant, and an ionic liquid as electrolyte. The ionic electrolyte allows operation in space vacuum without any seals. A unique, space-durable coating applied to the external surface of the skins drastically lowers the solar absorptance of the skins, such that in their dark (highly emissive) electrochromic state, it is no more than 0.44, whilst in their light electrochromic state, it is ca. 0.3. Data presented show tailorable, variations from 0.19 to 0.90, ∀(s)<0.3, and nearly indefinite cyclability. Extended thermal vacuum, atomic-O, micrometeoroid, VUV and other studies show excellent space durability. Performance of a doughnut-shaped skin designed for a specific micro-spacecraft is also described.

Stabilization of He2(A(sup 3)Sigma(sub u)(+)) molecules in liquid helium by optical pumping for vacuum UV laser

NASA Technical Reports Server (NTRS)

Zmuidzinas, J. S. (Inventor)

1978-01-01

A technique is disclosed for achieving large populations of metastable spin-aligned He2(a 3 Sigma u +) molecules in superfluid helium to obtain lasing in the vacuum ultraviolet wavelength regime around 0.0800 micron m by electronically exciting liquid (superfluid) helium with a comparatively low-current electron beam and spin aligning the metastable molecules by means of optical pumping with a modestly-powered (100mW) circularly-polarized continuous wave laser operating at, for example, 0.9096 or 0.4650 micron m. Once a high concentration of spin-aligned He2 (a 3 Sigma u +) is achieved with lifetimes of a few milliseconds, a strong microwave signal destroys the spin alignment and induces a quick collisional transition of He2 (a 3 Sigma u +) molecules to the a 1 Sigma u + state and thereby a lasing transition to the X 1 Sigma g + state.

Purfication kinetics of beryllium during vacuum induction melting

NASA Technical Reports Server (NTRS)

Mukherjee, J. L.; Gupta, K. P.; Li, C. H.

1972-01-01

The kinetics of evaporation in binary alloys were quantitatively treated. The formalism so developed works well for several systems studied. The kinetics of purification of beryllium was studied through evaporation data actually acquired during vacuum induction melting. Normal evaporation equations are shown to be generally valid and useful for understanding the kinetics of beryllium purification. The normal evaporation analysis has been extended to cover cases of limited liquid diffusion. It was shown that under steady-state evaporation, the solute concentration near the surface may be up to six orders of magnitude different from the bulk concentration. Corrections for limited liquid diffusion are definitely needed for the highly evaporative solute elements, such as Zn, Mg, and Na, for which the computed evaporation times are improved by five orders of magnitude. The commonly observed logarithmic relation between evaporation time and final concentration further supports the validity of the normal evaporation equations.

Transport of liquid state nitrogen through long length service lines during thermal/vacuum testing. [in a Nimbus 6 satellite

NASA Technical Reports Server (NTRS)

Florio, F. A.

1975-01-01

Physical and analytical aspects associated with the transport are presented. Included is a definition of the problems and difficulties imposed by the servicing of a typical solid cryogen system, as well as a discussion of the transport requirements and of the rationale which governed their solution. A successful detailed transport configuration is defined, and the application of established mathematics to the design approach is demonstrated. The significance of head pressure, pressure drop, line friction, heat leak, Reynolds number, and the fundamental equilibrium demands of pressure and temperature were examined as they relate to the achievement of liquid state flow. Performance predictions were made for the transport system, and several analytical quantities are tabulated. These data are analyzed and compared with measured and calculated results obtained while actually servicing a solid cryogen system during thermal/vacuum testing.

Atmospheric cloud physics laboratory project study

NASA Technical Reports Server (NTRS)

Schultz, W. E.; Stephen, L. A.; Usher, L. H.

1976-01-01

Engineering studies were performed for the Zero-G Cloud Physics Experiment liquid cooling and air pressure control systems. A total of four concepts for the liquid cooling system was evaluated, two of which were found to closely approach the systems requirements. Thermal insulation requirements, system hardware, and control sensor locations were established. The reservoir sizes and initial temperatures were defined as well as system power requirements. In the study of the pressure control system, fluid analyses by the Atmospheric Cloud Physics Laboratory were performed to determine flow characteristics of various orifice sizes, vacuum pump adequacy, and control systems performance. System parameters predicted in these analyses as a function of time include the following for various orifice sizes: (1) chamber and vacuum pump mass flow rates, (2) the number of valve openings or closures, (3) the maximum cloud chamber pressure deviation from the allowable, and (4) cloud chamber and accumulator pressure.

Organic oxalate as leachant and precipitant for the recovery of valuable metals from spent lithium-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun Liang; Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Ministry of Education of the People's Republic of China; Qiu Keqiang, E-mail: qiuwhs@sohu.com

2012-08-15

Graphical abstract: Display Omitted Highlights: Black-Right-Pointing-Pointer Vacuum pyrolysis as a pretreatment was used to separate cathode material from aluminum foils. Black-Right-Pointing-Pointer Cobalt and lithium can be leached using oxalate while cobalt can be directly precipitated as cobalt oxalate. Black-Right-Pointing-Pointer Cobalt and lithium can be separated efficiently from each other only in the oxalate leaching process. Black-Right-Pointing-Pointer High reaction efficiency of LiCoO{sub 2} was obtained with oxalate. - Abstract: Spent lithium-ion batteries containing lots of strategic resources such as cobalt and lithium are considered as an attractive secondary resource. In this work, an environmentally compatible process based on vacuum pyrolysis, oxalatemore » leaching and precipitation is applied to recover cobalt and lithium from spent lithium-ion batteries. Oxalate is introduced as leaching reagent meanwhile as precipitant which leaches and precipitates cobalt from LiCoO{sub 2} and CoO directly as CoC{sub 2}O{sub 4}{center_dot}2H{sub 2}O with 1.0 M oxalate solution at 80 Degree-Sign C and solid/liquid ratio of 50 g L{sup -1} for 120 min. The reaction efficiency of more than 98% of LiCoO{sub 2} can be achieved and cobalt and lithium can also be separated efficiently during the hydrometallurgical process. The combined process is simple and adequate for the recovery of valuable metals from spent lithium-ion batteries.« less

Cryogenic Testing of Different Seam Concepts for Multilayer Insulation Systems

NASA Technical Reports Server (NTRS)

Johnson, Wesley L.; Fesmire, J. E.

2009-01-01

Recent testing in a cylindrical, comparative cryostat at the Cryogenics Test Laboratory has focused on various seam concepts for multilayer insulation systems. Three main types of seams were investigated: straight overlap, fold-over, and roll wrapped. Each blanket was comprised of 40 layer pairs of reflector and spacer materials. The total thickness was approximately 12.5-mm, giving an average layer density of 32 layers per centimeter. The blankets were tested at high vacuum, soft vacuum, and no vacuum using liquid nitrogen to maintain the cold boundary temperature at 77 K. Test results show that all three seam concepts are all close in thermal performance; however the fold-over method provides the lowest heat flux. For the first series of tests, seams were located 120 degrees around the circumference of the cryostat from the previous seam. This technique appears to have lessened the degradation of the blanket due to the seams. In a follow-on test, a 20 layer blanket was tested in a roll wrapped configuration and then cut down the side of the cylinder, taped together, and re-tested. This test result shows the thermal performance impact of having the seams all in one location versus having the seams clocked around the vessel. This experimental investigation indicates that the method of joining the seams in multilayer insulation systems is not as critical as the quality of the installation process.

Impact of vacuum cooking process on the texture degradation of selected apple cultivars.

PubMed

Bourles, E; Mehinagic, E; Courthaudon, J L; Jourjon, F

2009-01-01

Thermal treatments are known to affect the textural properties of fruits and vegetables. This study was conducted to evaluate the influence of vacuum cooking process on the mechanical properties of various apple cultivars. A total of 10 apple cultivars were industrially processed by vacuum pasteurization at 95 degrees C for 25 min. The raw material was characterized by penetrometry, uniaxial double compression, soluble solid content, and titrable acidity. Textural properties of processed apples were analyzed by uniaxial double compression. As expected, for all cultivars, fruit resistance was lower after processing than before. Results showed that texture degradation due to vacuum pasteurization was different from one cultivar to another. Indeed, some cultivars, initially considered as the most resistant ones, such as Braeburn, were less suitable for processing, and became softer than others after thermal treatment. Consequently, it is worth noting that the texture classification of the investigated apple cultivars was changed by the vacuum-cooking process.

Space processing of composite materials

NASA Technical Reports Server (NTRS)

Steurer, W. H.; Kaye, S.

1975-01-01

Materials and processes for the testing of aluminum-base fiber and particle composites, and of metal foams under extended-time low-g conditions were investigated. A wetting and dispersion technique was developed, based on the theory that under the absence of a gas phase all solids are wetted by liquids. The process is characterized by a high vacuum environment and a high temperature cycle. Successful wetting and dispersion experiments were carried out with sapphire fibers, whiskers and particles, and with fibers of silicon carbide, pyrolytic graphite and tungsten. The developed process and facilities permit the preparation of a precomposite which serves as sample material for flight experiments. Low-g processing consists then merely in the uniform redistribution of the reinforcements during a melting cycle. For the preparation of metal foams, gas generation by means of a thermally decomposing compound was found most adaptable to flight experiments. For flight experiments, the use of compacted mixture of the component materials limits low-g processing to a simple melt cycle.

Vacuum Pressureless Sintering of Ti-6Al-4V Alloy with Full Densification and Forged-Like Mechanical Properties

NASA Astrophysics Data System (ADS)

Zhang, Ce; Lu, Boxin; Wang, Haiying; Guo, Zhimeng; Paley, Vladislav; Volinsky, Alex A.

2018-01-01

Ti-6Al-4V ingots with a nearly 100% density, fine and homogeneous basket-weave microstructure, and better comprehensive mechanical properties (UTS = 935 MPa, Y.S. = 865 MPa, El. = 15.8%), have been manufactured by vacuum pressureless sintering of blended elemental powders. Coarse TiH2 powder, Al powder (2, 20 μm), V powder, and Al-V master alloy powder were used as raw materials to produce different powder mixtures ( D 50 = 10 μm). Then, the compacts made by cold isostatic pressing were consolidated by different sintering curves. A detailed investigation of different as-sintered samples revealed that a higher density can be obtained by generating transient molten Al in the sintering process. Coarse Al powder and a rapid heating rate under the melting point of Al contribute to molten Al formation. The presence of temporary liquid phase changes the sintering mechanism, accelerating the sintering neck formation, improving sinterability of the powder mixtures. Density of 99.5% was achieved at 1150 °C, which is markedly lower than the sintering temperatures reported for conventional blended elemental powder metallurgy routes. In addition, low interstitial content, especially for oxygen (0.17 wt.%), is obtained by strict process control.

Cold Test and Performance Evaluation of Prototype Cryoline-X

NASA Astrophysics Data System (ADS)

Shah, N.; Choukekar, K.; Kapoor, H.; Muralidhara, S.; Garg, A.; Kumar, U.; Jadon, M.; Dash, B.; Bhattachrya, R.; Badgujar, S.; Billot, V.; Bravais, P.; Cadeau, P.

2017-12-01

The multi-process pipe vacuum jacketed cryolines for the ITER project are probably world’s most complex cryolines in terms of layout, load cases, quality, safety and regulatory requirements. As a risk mitigation plan, design, manufacturing and testing of prototype cryoline (PTCL) was planned before the approval of final design of ITER cryolines. The 29 meter long PTCL consist of 6 process pipes encased by thermal shield inside Outer Vacuum Jacket of DN 600 size and carries cold helium at 4.5 K and 80 K. The global heat load limit was defined as 1.2 W/m at 4.5 K and 4.5 W/m at 80 K. The PTCL-X (PTCL for Group-X cryolines) was specified in detail by ITER-India and designed as well as manufactured by Air Liquide. PTCL-X was installed and tested at cryogenic temperature at ITER-India Cryogenic Laboratory in 2016. The heat load at 4.5 K and 80 K, estimated using enthalpy difference method, was found to be approximately 0.8 W/m at 4.5 K, 4.2 W/m at 80 K, which is well within the defined limits. Thermal shield temperature profile was also found to be satisfactory. Paper summarizes the cold test results of PTCL-X

Quantum-state resolved reactive scattering at the gas-liquid interface: F+squalane (C30H62) dynamics via high-resolution infrared absorption of nascent HF(v,J).

PubMed

Zolot, Alexander M; Dagdigian, Paul J; Nesbitt, David J

2008-11-21

Exothermic chemical reaction dynamics at the gas-liquid interface have been investigated by colliding a supersonic beam of F atoms [E(com)=0.7(3) kcalmol] with a continuously refreshed liquid hydrocarbon (squalane) surface under high vacuum conditions. Absolute HF(v,J) product densities are determined by infrared laser absorption spectroscopy, with velocity distributions along the probe axis derived from high resolution Dopplerimetry. Nascent HF(v

Quantum-state resolved reactive scattering at the gas-liquid interface: F +squalane (C30H62) dynamics via high-resolution infrared absorption of nascent HF(v,J)

NASA Astrophysics Data System (ADS)

Zolot, Alexander M.; Dagdigian, Paul J.; Nesbitt, David J.

2008-11-01

Exothermic chemical reaction dynamics at the gas-liquid interface have been investigated by colliding a supersonic beam of F atoms [Ecom=0.7(3)kcal/mol] with a continuously refreshed liquid hydrocarbon (squalane) surface under high vacuum conditions. Absolute HF(v,J) product densities are determined by infrared laser absorption spectroscopy, with velocity distributions along the probe axis derived from high resolution Dopplerimetry. Nascent HF(v ⩽3) products are formed in a highly nonequilibrium (inverted) vibrational distribution [⟨Evib⟩=13.2(2)kcal/mol], reflecting insufficient time for complete thermal accommodation with the surface prior to desorption. Colder, but still non-Boltzmann, rotational state populations [⟨Erot⟩=1.0(1)kcal/mol] indicate that some fraction of molecules directly scatter into the gas phase without rotationally equilibrating with the surface. Nascent HF also recoils from the liquid surface with excess translational energy, resulting in Doppler broadened linewidths that increase systematically with internal HF excitation. The data are consistent with microscopic branching in HF-surface dynamics following the reactive event, with (i) a direct reactive scattering fraction of newly formed product molecules leaving the surface promptly and (ii) a trapping desorption fraction that accommodates rotationally (though still not vibrationally) with the bulk liquid. Comparison with analogous gas phase F +hydrocarbon processes reveals that the liquid acts as a partial "heat sink" for vibrational energy flow on the time scale of the chemical reaction event.

COLD TRAP

DOEpatents

Milleron, N.

1963-03-12

An improved linear-flow cold trap is designed for highvacuum applications such as mitigating back migration of diffusion pump oil moiecules. A central pot of liquid nitrogen is nested within and supported by a surrounding, vertical, helical coil of metai sheet, all enveloped by a larger, upright, cylindrical, vacuum vessel. The vertical interstices between successive turns of the coil afford lineal, axial, high-vacuum passages between open mouths at top and bottom of said vessel, while the coil, being cold by virtue of thermal contact of its innermost turn with the nitrogen pot, affords expansive proximate condensation surfaces. (AEC)

Compact scanning tunneling microscope for spin polarization measurements.

PubMed

Kim, Seong Heon; de Lozanne, Alex

2012-10-01

We present a design for a scanning tunneling microscope that operates in ultrahigh vacuum down to liquid helium temperatures in magnetic fields up to 8 T. The main design philosophy is to keep everything compact in order to minimize the consumption of cryogens for initial cool-down and for extended operation. In order to achieve this, new ideas were implemented in the design of the microscope body, dewars, vacuum chamber, manipulators, support frame, and vibration isolation. After a brief description of these designs, the results of initial tests are presented.

Experimental evaluation of a 600 lbf spacecraft rocket engine.

NASA Technical Reports Server (NTRS)

Hoehn, F. W.

1972-01-01

Experimental results are presented for a long-duration-capability (1000-sec), space-storable, bipropellant liquid rocket motor burning fluorine/hydrazine or FLOX/monomethylhydrazine. The interrelationship between injected mixture ratio and the per cent film cooling on vacuum specific impulse performance and chamber heat transfer is given. Experimental sea level measurements are used to predict space vacuum performance based upon simplified JANNAF reference procedures. Dynamic combustion stability is demonstrated over a wide range of operating conditions. Analytical results of char penetration, erosion, and ablative wall temperature distributions are presented for prototype chamber designs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Restivo, M.

SRNL Environmental and Chemical Process Technology (E&CPT) was requested to perform testing of vacuum pumps per a verbal request from the Customer, SRNL Hydrogen Processing Technology. Tritium Operations is currently having difficulties procuring the Normetex™® Model 15 m 3/hr (9 CFM) vacuum pump (formerly Normetex Pompes, now Eumeca SARL). One possible solution proposed by Hydrogen Processing Technology personnel is to use two Senior Aerospace Metal Bellows MB-601 vacuum pumps piped with the heads in series, and the pumps in series (Figure 1 below). This memorandum documents the ultimate vacuum testing that was performed to determine if this concept was amore » viable alternate vacuum pump strategy. This testing dovetails with previous pump evaluations documented in references 1 and 2.« less

Characterization of a Pressure-Fed LOX/LCH4 Reaction Control System Under Simulated Altitude and Thermal Vacuum Conditions

NASA Technical Reports Server (NTRS)

Atwell, Matthew J.; Melcher, John C.; Hurlbert, Eric A.; Morehead, Robert L.

2017-01-01

A liquid oxygen, liquid methane (LOX/LCH4) reaction control system (RCS) was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under simulated altitude and thermal vacuum conditions. The RCS is a subsystem of the Integrated Cryogenic Propulsion Test Article (ICPTA) and was initially developed under Project Morpheus. Composed of two 28 lbf-thrust and two 7 lbf-thrust engines, the RCS is fed in parallel with the ICPTA main engine from four propellant tanks. 40 tests consisting of 1,010 individual thruster pulses were performed across 6 different test days. Major test objectives were focused on system dynamics, and included characterization of fluid transients, manifold priming, manifold thermal conditioning, thermodynamic vent system (TVS) performance, and main engine/RCS interaction. Peak surge pressures from valve opening and closing events were examined. It was determined that these events were impacted significantly by vapor cavity formation and collapse. In most cases the valve opening transient was more severe than the valve closing. Under thermal vacuum conditions it was shown that TVS operation is unnecessary to maintain liquid conditions at the thruster inlets. However, under higher heat leak environments the RCS can still be operated in a self-conditioning mode without overboard TVS venting, contingent upon the engines managing a range of potentially severe thermal transients. Lastly, during testing under cold thermal conditions the engines experienced significant ignition problems. Only after warming the thruster bodies with a gaseous nitrogen purge to an intermediate temperature was successful ignition demonstrated.

A hydrogen leak-tight, transparent cryogenic sample container for ultracold-neutron transmission measurements

NASA Astrophysics Data System (ADS)

Döge, Stefan; Hingerl, Jürgen

2018-03-01

The improvement of the number of extractable ultracold neutrons (UCNs) from converters based on solid deuterium (sD2) crystals requires a good understanding of the UCN transport and how the crystal's morphology influences its transparency to the UCNs. Measurements of the UCN transmission through cryogenic liquids and solids of interest, such as hydrogen (H2) and deuterium (D2), require sample containers with thin, highly polished and optically transparent windows and a well defined sample thickness. One of the most difficult sealing problems is that of light gases like hydrogen and helium at low temperatures against high vacuum. Here we report on the design of a sample container with two 1 mm thin amorphous silica windows cold-welded to aluminum clamps using indium wire gaskets, in order to form a simple, reusable, and hydrogen-tight cryogenic seal. The container meets the above-mentioned requirements and withstands up to 2 bar hydrogen gas pressure against isolation vacuum in the range of 10-5 to 10-7 mbar at temperatures down to 4.5 K. Additionally, photographs of the crystallization process are shown and discussed.

Vacuum FTIR Observation on the Dynamic Hygroscopicity of Aerosols under Pulsed Relative Humidity.

PubMed

Leng, Chun-Bo; Pang, Shu-Feng; Zhang, Yun; Cai, Chen; Liu, Yong; Zhang, Yun-Hong

2015-08-04

A novel approach based on a combination of a pulse RH controlling system and a rapid scan vacuum FTIR spectrometer (PRHCS-RSVFTIR) was utilized to investigate dynamic hygroscopicity of two atmospheric aerosols: ammonium sulfate ((NH4)2SO4) and magnesium sulfate (MgSO4). In this approach, rapid-scan infrared spectra of water vapor and aerosols were obtained to determine relative humidity (RH) in sample cell and hygroscopic property of aerosols with a subsecond time resolution. Heterogeneous nucleation rates of (NH4)2SO4 were, for the first time, measured under low RH conditions (<35% RH). In addition, studies of MgSO4 aerosols revealed that water mass transport may be limited by different processes depending on RH values (surface limited at 40% < RH < 52% and bulk phase limited at RH < 40%). Furthermore, we are also the first to report water diffusion constants in micron size MgSO4 aerosols at very low RH values. Our results have shown that the PRHCS-RSVFTIR is well-suited for determination of hygroscopicity of atmospheric aerosols and water transport and nucleation kinetics of liquid aerosols.

Soft x-ray spectroscopy of high pressure liquid.

PubMed

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; Macdougall, James; Pepper, John; Armitage, Kevin; Borsos, Jason; Knauss, Kevin G; Lee, Namhey; Allézy, Arnaud; Gilbert, Benjamin; MacDowell, Alastair A; Liu, Yi-Sheng; Glans, Per-Anders; Sun, Xuhui; Chao, Weilun; Guo, Jinghua

2018-01-01

We describe a new experimental technique that allows for soft x-ray spectroscopy studies (∼100-1000 eV) of high pressure liquid (∼100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3 N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3 N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3 N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length of the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3 N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3 N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (∼350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.

Soft x-ray spectroscopy of high pressure liquid

DOE PAGES

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; ...

2018-01-01

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

Soft x-ray spectroscopy of high pressure liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

Advanced liquefaction using coal swelling and catalyst dispersion techniques. Quarterly progress report, July--September 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis, C.W.; Gutterman, C.; Chander, S.

The overall objective of this project is to develop a new approach for the direct liquefaction of coal to produce an all-distillate product slate at a sizable cost reduction over current technology. The approach integrates coal selection, pretreatment, coal swelling with catalyst impregnation, liquefaction, product recovery with characterization, alternate bottoms processing, and carrying out a technical assessment including an economic evaluation. The primary coal of this program, Black Thunder subbituminous coal, can be effectively beneficiated to about 3.5 wt % ash using aqueous sulfurous acid pretreatment. This treated coal can be further beneficiated to about 2 wt % ash usingmore » commercially available procedures. All three coals used in this study (Black Thunder, Burning Star bituminous, and Martin Lake lignite) are effectively swelled by a number of solvents. The most effective solvents are those having hetero-functionality. laboratory- and bench-scale liquefaction experimentation is underway using swelled and catalyst impregnated coal samples. Higher coal conversions were observed for the SO{sub 2}-treated subbituminous coal than the raw coal, regardless of catalyst type. Conversions of swelled coal were highest when Molyvan L, molybdenum naphthenate, and nickel octoate, respectively, were added to the liquefaction solvent. The study of bottoms processing consists of combining the ASCOT process which consists of coupling solvent deasphalting with delayed coking to maximize the production of coal-derived liquids while rejecting solids within the coke drum. The asphalt production phase has been completed; representative product has been evaluated. The solvent system for the deasphalting process has been established. Two ASCOT tests produced overall liquid yields (63.3 wt % and 61.5 wt %) that exceeded the combined liquid yields from the vacuum tower and ROSE process.« less

Thermophysical Property Measurements in the MSFC ESL

NASA Technical Reports Server (NTRS)

Hyers, R. W.; Rogers, J. R.; Robinson, M. B.; Rathz, T. J.; Curreri, Peter A. (Technical Monitor)

2002-01-01

Electrostatic Levitation (ESL) is an advanced technique for containerless processing of metals, ceramics, and semiconductors. Because no container is required, there is no contamination from reaction with a crucible, allowing processing of high temperature, highly reactive melts. The high vacuum processing environment further reduces possible contamination of the samples. Finally, there is no container to provide heterogeneous nucleation sites, so the undercooled range is also accessible for many materials. For these reasons, ESL provides a unique environment for measuring thermophysical properties of liquid materials. The properties that can be measured in ESL include density, surface tension, viscosity, electrical and thermal conductivity, specific heat, phase diagram, TTT- and CCT- curves, and other thermodynamic properties. In this paper, we present data on surface tension and viscosity, measured by the oscillating drop technique, and density, measured by an automated photographic technique, measured in the ESL at NASA Marshall Space Flight Center.

Modification of fast-growing Chinese Fir wood with unsaturated polyester resin: Impregnation technology and efficiency

NASA Astrophysics Data System (ADS)

Ma, Qing; Zhao, Zijian; Yi, Songlin; Wang, Tianlong

In this study, Chinese Fir was impregnated with unsaturated polyester resin to enhance its properties. Samples 20 mm × 20 mm × 20 mm in size were split into different sections with epoxy resin and tinfoil and subjected to an impregnation experiment under various parameters. Vacuum degree was -0.04 MPa, -0.06 MPa or -0.08 MPa and vacuum duration was 15 min, 30 min, or 45 min. The results indicated that impregnation weight percent gain is linearly dependent on curing weight percent gain. Vacuum duration appears to have less influence on the curing weight percent gain than vacuum degree, and impregnation was most successful at the transverse section compared to other sections. The optimal impregnation parameters were 30 min modification under -0.08 MPa vacuum followed by 120 min at atmospheric pressure for samples 200 mm × 100 mm × 20 mm in size. Uneven distribution of weight percent gain and cracking during the curing process suggested that 30 min post-processing at -0.09 MPa vacuum was the most effective way to complete the impregnation process. The sample's bending strength and modulus of elasticity increased after impregnation treatment. Bending strength after impregnation without post-processing reached 112.85%, but reached 71.65% with vacuum-processing; modulus of elasticity improved 67.13% and 58.28% without and with post-processing, respectively.

Cryogenic Thermal Performance Testing of Bulk-Fill and Aerogel Insulation Materials

NASA Astrophysics Data System (ADS)

Scholtens, B. E.; Fesmire, J. E.; Sass, J. P.; Augustynowicz, S. D.; Heckle, K. W.

2008-03-01

Thermal conductivity testing under actual-use conditions is a key to understanding how cryogenic thermal insulation systems perform in regard to engineering, economics, and materials factors. The Cryogenics Test Laboratory at NASA's Kennedy Space Center tested a number of bulk-fill insulation materials, including aerogel beads, glass bubbles, and perlite powder, using a new cylindrical cryostat. Boundary temperatures for the liquid nitrogen boiloff method were 78 K and 293 K. Tests were performed as a function of cold vacuum pressure under conditions ranging from high vacuum to no vacuum. Results were compared with those from complementary test methods in the range of 20 K to 300 K. Various testing techniques are required to completely understand the operating performance of a material and to provide data for answers to design engineering questions.

Task-Specific Ionic Liquids for Mars Exploration (Green Chemistry for a Red Planet)

NASA Technical Reports Server (NTRS)

Karr, L. J.; Curreri, P. A.; Paley, M. S.; Kaukler, W. F.; Marone, M. J.

2012-01-01

Ionic Liquids (ILs) are organic salts with low melting points that are liquid at or near room temperature. The combinations of available ions and task-specific molecular designability make them suitable for a huge variety of tasks. Because of their low flammability, low vapor pressure, and stability in harsh environments (extreme temperatures, hard vacuum) they are generally much safer and "greener" than conventional chemicals and are thus suitable for a wide range of applications that support NASA exploration goals. This presentation describes several of the ongoing applications that are being developed at MSFC.

Recent advances in vacuum sciences and applications

NASA Astrophysics Data System (ADS)

Mozetič, M.; Ostrikov, K.; Ruzic, D. N.; Curreli, D.; Cvelbar, U.; Vesel, A.; Primc, G.; Leisch, M.; Jousten, K.; Malyshev, O. B.; Hendricks, J. H.; Kövér, L.; Tagliaferro, A.; Conde, O.; Silvestre, A. J.; Giapintzakis, J.; Buljan, M.; Radić, N.; Dražić, G.; Bernstorff, S.; Biederman, H.; Kylián, O.; Hanuš, J.; Miloševič, S.; Galtayries, A.; Dietrich, P.; Unger, W.; Lehocky, M.; Sedlarik, V.; Stana-Kleinschek, K.; Drmota-Petrič, A.; Pireaux, J. J.; Rogers, J. W.; Anderle, M.

2014-04-01

Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solid-liquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented.

Solar Simulation for the CREST Preflight Thermal-Vacuum Test at B-2

NASA Technical Reports Server (NTRS)

Ziemke, Robert A.

2012-01-01

In June 2011, the multi-university sponsored Cosmic Ray Electron Synchrotron Telescope (CREST) has undergone thermal-vacuum qualification testing at the NASA Glenn Research Center (GRC), Plum Brook Station, Sandusky, Ohio. The testing was performed in the B-2 Space Propulsion Facility vacuum chamber. The CREST was later flown over the Antarctic region as the payload of a stratospheric balloon. Solar simulation was provided by a system of planar infrared lamp arrays specifically designed for CREST. The lamp arrays, in conjunction with a liquid-nitrogen-cooled cold wall, achieved the required thermal conditions for the qualification tests. The following slides accompanied the presentation of the report entitled Solar Simulation for the CREST Preflight Thermal-Vacuum Test at B-2, at the 27th Aerospace Testing Seminar, October 2012. The presentation described the test article, the test facility capability, the solar simulation requirements, the highlights of the engineering approach, and the results achieved. The presentation was intended to generate interest in the report and in the B-2 test facility.

Synthesis of α-linolenic acid-rich triacylglycerol using a newly prepared immobilized lipase.

PubMed

Kim, Heejin; Choi, Nakyung; Oh, Se-Wook; Kim, Yangha; Hee Kim, Byung; Kim, In-Hwan

2017-12-15

An α-linolenic acid (ALA)-rich triacylglycerol (TAG) was synthesized from an ALA-rich fatty acid (FA) from perilla oil and glycerol, using a newly prepared immobilized lipase under vacuum. The ALA-rich FA (purity >90wt%) used as the substrate was prepared by urea complexation from perilla oil FAs. Liquid Lipozyme TL 100L lipase from Thermomyces lanuginosus was used for immobilization. Nine different hydrophilic and hydrophobic carriers for immobilization were tested, and Duolite A568, which is a hydrophilic resin, was selected as the best carrier. This immobilized lipase was used to synthesize TAG by direct esterification under vacuum. The parameters investigated were temperature, enzyme loading, and vacuum level. The optimum reaction conditions were a temperature of 60°C, an enzyme loading of 15% (based on the total weight of the substrate), and a vacuum of 0.7kPa, respectively. The maximum conversion to TAG of ca. 88wt% was obtained in 12h under the optimum conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

A thin polymer membrane, nano-suit, enhancing survival across the continuum between air and high vacuum

PubMed Central

Takaku, Yasuharu; Suzuki, Hiroshi; Ohta, Isao; Ishii, Daisuke; Muranaka, Yoshinori; Shimomura, Masatsugu; Hariyama, Takahiko

2013-01-01

Most multicellular organisms can only survive under atmospheric pressure. The reduced pressure of a high vacuum usually leads to rapid dehydration and death. Here we show that a simple surface modification can render multicellular organisms strongly tolerant to high vacuum. Animals that collapsed under high vacuum continued to move following exposure of their natural extracellular surface layer (or that of an artificial coat-like polysorbitan monolaurate) to an electron beam or plasma ionization (i.e., conditions known to enhance polymer formation). Transmission electron microscopic observations revealed the existence of a thin polymerized extra layer on the surface of the animal. The layer acts as a flexible “nano-suit” barrier to the passage of gases and liquids and thus protects the organism. Furthermore, the biocompatible molecule, the component of the nano-suit, was fabricated into a “biomimetic” free-standing membrane. This concept will allow biology-related fields especially to use these membranes for several applications. PMID:23589878

25th Space Simulation Conference. Environmental Testing: The Earth-Space Connection

NASA Technical Reports Server (NTRS)

Packard, Edward

2008-01-01

Topics covered include: Methods of Helium Injection and Removal for Heat Transfer Augmentation; The ESA Large Space Simulator Mechanical Ground Support Equipment for Spacecraft Testing; Temperature Stability and Control Requirements for Thermal Vacuum/Thermal Balance Testing of the Aquarius Radiometer; The Liquid Nitrogen System for Chamber A: A Change from Original Forced Flow Design to a Natural Flow (Thermo Siphon) System; Return to Mercury: A Comparison of Solar Simulation and Flight Data for the MESSENGER Spacecraft; Floating Pressure Conversion and Equipment Upgrades of Two 3.5kw, 20k, Helium Refrigerators; Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load; Special ISO Class 6 Cleanroom for the Lunar Reconnaissance Orbiter (LRO) Project; A State-of-the-Art Contamination Effects Research and Test Facility Martian Dust Simulator; Cleanroom Design Practices and Their Influence on Particle Counts; Extra Terrestrial Environmental Chamber Design; Contamination Sources Effects Analysis (CSEA) - A Tool to Balance Cost/Schedule While Managing Facility Availability; SES and Acoustics at GSFC; HST Super Lightweight Interchangeable Carrier (SLIC) Static Test; Virtual Shaker Testing: Simulation Technology Improves Vibration Test Performance; Estimating Shock Spectra: Extensions beyond GEVS; Structural Dynamic Analysis of a Spacecraft Multi-DOF Shaker Table; Direct Field Acoustic Testing; Manufacture of Cryoshroud Surfaces for Space Simulation Chambers; The New LOTIS Test Facility; Thermal Vacuum Control Systems Options for Test Facilities; Extremely High Vacuum Chamber for Low Outgassing Processing at NASA Goddard; Precision Cleaning - Path to Premier; The New Anechoic Shielded Chambers Designed for Space and Commercial Applications at LIT; Extraction of Thermal Performance Values from Samples in the Lunar Dust Adhesion Bell Jar; Thermal (Silicon Diode) Data Acquisition System; Aquarius's Instrument Science Data System (ISDS) Automated to Acquire, Process, Trend Data and Produce Radiometric System Assessment Reports; Exhaustive Thresholds and Resistance Checkpoints; Reconfigurable HIL Testing of Earth Satellites; FPGA Control System for the Automated Test of MicroShutters; Ongoing Capabilities and Developments of Re-Entry Plasma Ground Tests at EADS-ASTRIUM; Operationally Responsive Space Standard Bus Battery Thermal Balance Testing and Heat Dissipation Analysis; Galileo - The Serial-Production AIT Challenge; The Space Systems Environmental Test Facility Database (SSETFD), Website Development Status; Simulated Reentry Heating by Torching; Micro-Vibration Measurements on Thermally Loaded Multi-Layer Insulation Samples in Vacuum; High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suit Gas Processing System (GPS) Carbon Dioxide Scrubber; The Planning and Implementation of Test Facility Improvements; and Development of a Silicon Carbide Molecular Beam Nozzle for Simulation Planetary Flybys and Low-Earth Orbit.

Research of the cold shield in cryogenic liquid storage

NASA Astrophysics Data System (ADS)

Chen, L. B.; Zheng, J. P.; Wu, X. L.; Cui, C.; Zhou, Y.; Wang, J. J.

2017-12-01

To realize zero boil-off storage of cryogenic liquids, a cryocooler that can achieve a temperature below the boiling point temperature of the cryogenic liquid is generally needed. Taking into account that the efficiency of the cryocooler will be higher at a higher operating temperature, a novel thermal insulation system using a sandwich container filled with cryogenic liquid with a higher boiling point as a cold radiation shield between the cryogenic tank and the vacuum shield in room temperature is proposed to reduce the electricity power consumption. A two-stage cryocooler or two separate cryocoolers are adopted to condense the evaporated gas from the cold shield and the cryogenic tank. The calculation result of a 55 liter liquid hydrogen tank with a liquid nitrogen shield shows that only 14.4 W of electrical power is needed to make all the evaporated gas condensation while 121.7 W will be needed without the liquid nitrogen shield.

Description of Liquid Nitrogen Experimental Test Facility

NASA Technical Reports Server (NTRS)

Jurns, John M.; Jacobs, Richard E.; Saiyed, Naseem H.

1991-01-01

The Liquid Nitrogen Test Facility is a unique test facility for ground-based liquid nitrogen experimentation. The test rig consists of an insulated tank of approximately 12.5 cubic ft in volume, which is supplied with liquid nitrogen from a 300 gal dewar via a vacuum jacketed piping system. The test tank is fitted with pressure and temperature measuring instrumentation, and with two view ports which allow visual observation of test conditions. To demonstrate the capabilities of the facility, the initial test program is briefly described. The objective of the test program is to measure the condensation rate by injecting liquid nitrogen as a subcooled spray into the ullage of a tank 50 percent full of liquid nitrogen at saturated conditions. The condensation rate of the nitrogen vapor on the subcooled spray can be analytically modeled, and results validated and corrected by experimentally measuring the vapor condensation on liquid sprays.

Description of liquid nitrogen experimental test facility

NASA Technical Reports Server (NTRS)

Jurns, J. M.; Jacobs, R. E.; Saiyed, N. H.

1992-01-01

The Liquid Nitrogen Test Facility is a unique test facility for ground-based liquid nitrogen experimentation. The test rig consists of an insulated tank of approximately 12.5 cubic ft in volume, which is supplied with liquid nitrogen from a 300 gal dewar via a vacuum jacketed piping system. The test tank is fitted with pressure and temperature measuring instrumentation, and with two view ports which allow visual observation of test conditions. To demonstrate the capabilities of the facility, the initial test program is briefly described. The objective of the test program is to measure the condensation rate by injecting liquid nitrogen as a subcooled spray into the ullage of a tank 50 percent full of liquid nitrogen at saturated conditions. The condensation rate of the nitrogen vapor on the subcooled spray can be analytically modeled, and results validated and corrected by experimentally measuring the vapor condensation on liquid sprays.

A comparison between atmospheric/humidity and vacuum cyanoacrylate fuming of latent fingermarks.

PubMed

Farrugia, Kevin J; Fraser, Joanna; Friel, Lauren; Adams, Duncan; Attard-Montalto, Nicola; Deacon, Paul

2015-12-01

A number of pseudo-operational trials were set up to compare the atmospheric/humidity and vacuum cyanoacrylate fuming processes on plastic carrier bags. The fuming processes were compared using two-step cyanoacrylate fuming with basic yellow 40 (BY40) staining and a one-step fluorescent cyanoacrylate fuming, Lumicyano 4%. Preliminary work using planted fingermarks and split depletions were performed to identify the optimum vacuum fuming conditions. The first pseudo-operational trial compared the different fuming conditions (atmospheric/humidity vs. vacuum) for the two-step process where an additional 50% more marks were detected with the atmospheric/humidity process. None of the marks by the vacuum process could be observed visually; however, a significant number of marks were detected by fluorescence after BY40 staining. The second trial repeated the same work in trial 1 using the one-step cyanoacrylate process, Lumicyano at a concentration of 4%. Trial 2 provided comparable results to trial 1 and all the items were then re-treated with Lumicyano 4% at atmospheric/humidity conditions before dyeing with BY40 to provide the sequences of process A (Lumicyano 4% atmospheric-Lumicyano 4% atmospheric-BY40) and process B (Lumicyano 4% vacuum-Lumicyano 4% atmospheric-BY40). The number of marks (visual and fluorescent) was counted after each treatment with a substantial increase in the number of detected marks in the second and third treatments of the process. The increased detection rate after the double Lumicyano process was unexpected and may have important implications. Trial 3 was performed to investigate whether the amount of cyanoacrylate and/or fuming time had an impact on the results observed in trial 2 whereas trial 4 assessed if the double process using conventional cyanoacrylate, rather than Lumicyano 4%, provided an increased detection rate. Trials 3 and 4 confirmed that doubling the amount of Lumicyano 4% cyanoacrylate and fuming time produced a lower detection rate than the double process with Lumicyano 4%. Furthermore, the double process with conventional cyanoacrylate did not provide any benefit. Scanning electron microscopy was also performed to investigate the morphology of the cyanoacrylate polymer under different conditions. The atmospheric/humidity process appears to be superior to the vacuum process for both the two-step and one-step cyanoacrylate fuming, although the two-step process performed better in comparison to the one-step process under vacuum conditions. Nonetheless, the use of vacuum cyanoacrylate fuming may have certain operational advantages and its use does not adversely affect subsequent cyanoacrylate fuming with atmospheric/humidity conditions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Modification of a liquid hydrogen tank for integrated refrigeration and storage

NASA Astrophysics Data System (ADS)

Swanger, A. M.; Jumper, K. M.; Fesmire, J. E.; Notardonato, W. U.

2015-12-01

The modification and outfitting of a 125,000-liter liquid hydrogen tank was performed to provide integrated refrigeration and storage capability. These functions include zero boil-off, liquefaction, and densification and therefore require provisions for sub-atmospheric tank pressures within the vacuum-jacketed, multilayer insulated tank. The primary structural modification was to add stiffening rings inside the inner vessel. The internal stiffening rings were designed, built, and installed per the ASME Boiler and Pressure Vessel Code, Section VIII, to prevent collapse in the case of vacuum jacket failure in combination with sub-atmospheric pressure within the tank. For the integrated refrigeration loop, a modular, skeleton-type heat exchanger, with refrigerant temperature instrumentation, was constructed using the stiffening rings as supports. To support the system thermal performance testing, three custom temperature rakes were designed and installed along the 21-meter length of the tank, once again using rings as supports. The temperature rakes included a total of 20 silicon diode temperature sensors mounted both vertically and radially to map the bulk liquid temperature within the tank. The tank modifications were successful and the system is now operational for the research and development of integrated refrigeration technology.

Liquid gallium and the eutectic gallium indium (EGaIn) alloy: Dielectric functions from 1.24 to 3.1 eV by electrochemical reduction of surface oxides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morales, Daniel; Yu, Zhiyuan; Dickey, Michael D., E-mail: mddickey@ncsu.edu, E-mail: aspnes@ncsu.edu

Liquid metals based on gallium are promising materials for soft, stretchable, and shape reconfigurable electromagnetic devices. The behavior of these metals relates directly to the thicknesses of their surface oxide layers, which can be determined nondestructively by ellipsometry if their dielectric functions ε are known. This paper reports on the dielectric functions of liquid gallium and the eutectic gallium indium (EGaIn) alloy from 1.24 to 3.1 eV at room temperature, measured by spectroscopic ellipsometry. Overlayer-induced artifacts, a continuing problem in optical measurements of these highly reactive metals, are eliminated by applying an electrochemically reductive potential to the surface of the metalmore » immersed in an electrolyte. This technique enables measurements at ambient conditions while avoiding the complications associated with removing overlayers in a vacuum environment. The dielectric responses of both metals are closely represented by the Drude model. The EGaIn data suggest that in the absence of an oxide the surface is In-enriched, consistent with the previous vacuum-based studies. Possible reasons for discrepancies with previous measurements are discussed.« less

Comparative efficacy of house dust mite extermination products.

PubMed

Schober, G; Kniest, F M; Kort, H S; De Saint Georges Gridelet, D M; Van Bronswijk, J E

1992-06-01

The acaricidal efficacy of nine marketed products, i.e. Acardust, Acarosan (foam and powder), Actelic 50, Artilin 3A (spirit and water base), liquid nitrogen, Paragerm AK, and Tymasil, and of intensive vacuum-cleaning have been compared on four different test surfaces: mattress, tufted carpet, gypsum board and rough wooden board, all covered with artificial house dust. They were inoculated with the house dust mite, Dermatophagoides pteronyssinus or the house-dust fungus Aspergillus repens for evaluation of the fungistatic claims of some products. The acaricidal activity of Tymasil did not surpass that of vacuuming; its fungistatic effect was not apparent. The other products showed complete to almost complete eradication on at least one of the substrates tested. Taking into account the results of acaricidal efficacy as well as the data on safety and practicality acquired earlier, Acarosan powder was considered first choice for carpet treatment. Acarosan and liquid nitrogen, were found to be effective in the treatment of mattress, pillow, upholstered furniture and heavy curtains. On wooden surfaces Acarosan was found to be both effective and safe, while Acardust, Actelic 50, Artilin 3A (both fungistatic as well as acaricidal), liquid nitrogen and Paragerm also passed the efficiency test.

Vacuum mechatronics

NASA Technical Reports Server (NTRS)

Hackwood, Susan; Belinski, Steven E.; Beni, Gerardo

1989-01-01

The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

Automated Cryocooler Monitor and Control System

NASA Technical Reports Server (NTRS)

Britcliffe, Michael J.; Hanscon, Theodore R.; Fowler, Larry E.

2011-01-01

A system was designed to automate cryogenically cooled low-noise amplifier systems used in the NASA Deep Space Network. It automates the entire operation of the system including cool-down, warm-up, and performance monitoring. The system is based on a single-board computer with custom software and hardware to monitor and control the cryogenic operation of the system. The system provides local display and control, and can be operated remotely via a Web interface. The system controller is based on a commercial single-board computer with onboard data acquisition capability. The commercial hardware includes a microprocessor, an LCD (liquid crystal display), seven LED (light emitting diode) displays, a seven-key keypad, an Ethernet interface, 40 digital I/O (input/output) ports, 11 A/D (analog to digital) inputs, four D/A (digital to analog) outputs, and an external relay board to control the high-current devices. The temperature sensors used are commercial silicon diode devices that provide a non-linear voltage output proportional to temperature. The devices are excited with a 10-microamp bias current. The system is capable of monitoring and displaying three temperatures. The vacuum sensors are commercial thermistor devices. The output of the sensors is a non-linear voltage proportional to vacuum pressure in the 1-Torr to 1-millitorr range. Two sensors are used. One measures the vacuum pressure in the cryocooler and the other the pressure at the input to the vacuum pump. The helium pressure sensor is a commercial device that provides a linear voltage output from 1 to 5 volts, corresponding to a gas pressure from 0 to 3.5 MPa (approx. = 500 psig). Control of the vacuum process is accomplished with a commercial electrically operated solenoid valve. A commercial motor starter is used to control the input power of the compressor. The warm-up heaters are commercial power resistors sized to provide the appropriate power for the thermal mass of the particular system, and typically provide 50 watts of heat. There are four basic operating modes. "Cool " mode commands the system to cool to normal operating temperature. "Heat " mode is used to warm the device to a set temperature near room temperature. "Pump " mode is a maintenance function that allows the vacuum system to be operated alone to remove accumulated contaminants from the vacuum area. In "Off " mode, no power is applied to the system.

Vaporizable Scaffolds for Fabricating Thermoelectric Modules

NASA Technical Reports Server (NTRS)

Sakamoto, Jeffrey; Yen, Shiao-pin; Fleurial, Jean-Pierre; Paik, Jong-Ah

2006-01-01

A process for fabricating thermoelectric modules with vacuum gaps separating the thermoelectric legs has been conceived, and the feasibility of some essential parts of the process has been demonstrated. The vacuum gaps are needed to electrically insulate the legs from each other. The process involves the use of scaffolding in the form of sheets of a polymer to temporarily separate the legs by the desired distance, which is typically about 0.5 mm. During a bonding subprocess that would take place in a partial vacuum at an elevated temperature, the polymer would be vaporized, thereby creating the vacuum gaps.

Density of Solids and Liquids

DTIC Science & Technology

1950-03-15

coil, which has a resistance of 10 ohms, is surrounding the return pipe and by the tubular made of Chromel A or Nichrome V ’ibbon, coil, P, connected...stopcock. In filling the picnometer the liquid isplaced in funnel G and drawn in through E by exhausting the air through F. By this procedure much...instead of the original fairly constant by leakage through a screw pinch- vibrator head. This special head consists of a cock, P. If the maximum vacuum is

Volatility and Wear Characteristics of a Variety of Liquid Lubricants for Space Applications

NASA Technical Reports Server (NTRS)

Nguyen, QuynhGiao N.; Jones, William R., Jr.

2001-01-01

The vapor pressures and wear characteristics are critical properties for liquid lubricants to assure long-term reliability and performance in space applications. Vapor pressures, obtained using a Knudsen cell technique, and wear properties, obtained using a vacuum four-ball apparatus, were measured for a series of unformulated liquid lubricants. These included two multiply alkylated cyclopentanes (MACs) (X-1000 and X2000), two linear perfluoropolyalkylethers (PFPAEs) (Z-25 and 815Z), and four silahydrocarbons (a tri, a tetra, and two pentas). Vapor pressures were measured at three elevated temperatures (423, 448, and 498 K) and extrapolated to room temperature 298 K. The lowest 298 K vapor pressure of 5.7 x 10(exp -14) Pa was obtained with the PFPAE fluid (815Z) and the highest value with the low molecular weight MAC (X-1000) at 3.6 x 10(exp -7) Pa. In addition, vacuum wear rates were determined for some of the lubricants. The lowest wear rates (approximately 3 x 10(exp -11) cubic mm/mm) were observed for three of the silahydrocarbons while the highest wear rates (approximately 2 x 10(exp -9) cubic mm/mm) were observed with the two PFPAE fluids (Z-25 and 815Z). The MAC (X-2000) yielded a wear rate of about 10(exp -10) cubic mm/mm. The results indicated that the silahydrocarbon class of liquid lubricants offers the better potential for space applications.

Volatility and Wear Characteristics of a Variety of Liquid Lubricants for Space Applications

NASA Technical Reports Server (NTRS)

Nguyen, Quynhgiao N.; Jones, William R., Jr.

2001-01-01

The vapor pressures and near characteristics are critical properties for liquid lubricants to assure long-term reliability and performance in space applications. Vapor pressures, obtained using a Knudsen cell technique, and near properties, obtained using a vacuum four-ball apparatus, were measured for a series of unformulated liquid lubricants. These include: two multiple alkylated cyclopentanes (MACs) (X-1000 and X-2000), two linear perfluoropolyalkylethers (PFPAEs) (Z-25 and 815Z), and four silahydrocarbons (a tri-, a tetra-, and two pentas). Vapor pressures were measured at three elevated temperatures (423, 448, and 498 K) and extrapolated to room temperature 298 K. The lowest 298 K vapor pressure of 5.7 x 10(exp -14) Pa, was obtained with the PFPAE fluid (815Z) and the highest value with the low molecular weight MAC (X-1000) at 3.6 x 10(exp -7) Pa. In addition, vacuum near rates were determined for some of the lubricants. The lowest wear rates (approximately 3 x 10(exp -11) cubic mm/mm) were observed for three of the silahydrocarbons while the highest wear rate (approximately 2 x 10(exp-9) cubic mm/mm) were observed with the two PFPAE fluids (Z-25 and 815Z). The MAC (X-2000) yielded a wear rate of about 10(exp -10) cubic mm/mm. The results indicated that the silahydrocarbon class of liquid lubricants offers the better potential for space applications.

Structural evaluation of curved stiffened composite panels fabricated using a THERM-Xsm process

NASA Technical Reports Server (NTRS)

Kassapoglou, Christos; Dinicola, Albert J.; Chou, Jack C.; Deaton, Jerry W.

1991-01-01

The use of composites in aircraft structures is often limited by material and manufacturing costs which, for some designs and applications, are prohibitively high. To increase the frequency of application of composites in primary airframe components alternative manufacturing processes are sought that reduce cost and/or enhance structural efficiency. One alternative process involves the use of THERM-Xsm as the pressure transfer medium during autoclave curing. THERM-Xsm, a silicon-based flow able polymer which behaves like a liquid under autoclave presssure, transmits quasi-hydrostatic pressure to all contacting surfaces of the part to be cured. Once the autoclave pressure is relieved, THERM-Xsm reverts back to the powdery solid state and can be reused many times. The THERM-Xsm process to be evaluated is depicted and consists of (1) enclosing the tool and part to be cured by a set of frames that create a box, (2) pouring THERM-Xsm powder onto the part and filling the box, and (3) placing a vacuum bag over the box assembly. In this program, a separating non-porous film (Teflon) was placed between the part to be cured and THERM-Xsm powder to avoid any contamination. The use of THERM-Xsm has two significant advantages over conventional manufacturing procedures. First, it eliminates complicated hard tooling since it guarantees uniform pressure transfer and thus, good compaction at complex structural details (such as frame-stiffener intersections and corners). Second, it greatly simplifies vacuum bagging, since once the part to be cured is covered by THERM-Xsm powder, the vacuum bag need only conform to a relatively flat shape reducing significantly the number of pleats required. A program is on-going at Sikorsky Aircraft to evaluate the structural performance of complex composite fuselage structures made with this THERM-Xsm process and to quantify the impact of THERM-Xsm on manufacturing labor hours and cost. The program involves fuselage panel optimization analysis, a building block test program where structural details representative of the full-scale article are analyzed and tested, and static and fatigue test/analysis of the full-scale test articles. The main results of this program are reported.

Use of ammonia to reduce the viscosity of bottoms streams produced in hydroconversion processes

DOEpatents

Zaczepinski, Sioma; Billimoria, Rustom M.; Tao, Frank; Lington, Christopher G.; Plumlee, Karl W.

1984-01-01

Coal, petroleum residuum and similar carbonaceous feed materials are subjected to hydroconversion in the presence of molecular hydrogen to produce a hydroconversion effluent which is then subjected to one or more separation steps to remove lower molecular weight liquids and produce a heavy bottoms stream containing high molecular weight liquids and unconverted carbonaceous material. The viscosity of the bottoms streams produced in the separation step or steps is prevented from increasing rapidly by treating the feed to the separation step or steps with ammonia gas prior to or during the separation step or steps. The viscosity of the heavy bottoms stream produced in the final separation step is also controlled by treating these bottoms with ammonia gas. In a preferred embodiment of the invention, the effluent from the hydroconversion reactor is subjected to an atmospheric distillation followed by a vacuum distillation and the feeds to these distillations are contacted with ammonia during the distillations.

Example of a Fluid-Phase Change Examined with MD Simulation: Evaporative Cooling of a Nanoscale Droplet.

PubMed

Ao, Takashi; Matsumoto, Mitsuhiro

2017-10-24

We carried out a series of molecular dynamics simulations in order to examine the evaporative cooling of a nanoscale droplet of a Lennard-Jones liquid. After thermally equilibrating a droplet at a temperature T ini /T t ≃ 1.2 (T t is the triple-point temperature), we started the evaporation into vacuum by removing vaporized particles and monitoring the change in droplet size and the temperature inside. As free evaporation proceeds, the droplet reaches a deep supercooled liquid state of T/T t ≃ 0.7. The temperature was found to be uniform in spite of the fast evaporative cooling on the surface. The time evolution of the evaporating droplet properties was satisfactorily explained with a simple one-dimensional phase-change model. After a sufficiently long run, the supercooled droplet was crystallized into a polycrystalline fcc structure. The crystallization is a stochastic nucleation process. The time and the temperature of inception were evaluated over 42 samples, which indicate the existence of a stability limit.

Recent developments of the in situ wet cell technology for transmission electron microscopies.

PubMed

Chen, Xin; Li, Chang; Cao, Hongling

2015-03-21

In situ wet cells for transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) allow studying structures and processes in a liquid environment with high temporal and spatial resolutions, and have been attracting increasing research interests in many fields. In this review, we highlight the structural and functional developments of the wet cells for TEM and STEM. One of the key features of the wet cells is the sealing technique used to isolate the liquid sample from the TEM/STEM vacuum environments, thus the existing in situ wet cells are grouped by different sealing methods. In this study, the advantages and shortcomings of each type of in situ wet cells are discussed, the functional developments of different wet cells are presented, and the future trends of the wet cell technology are addressed. It is suggested that in the future the in situ wet cell TEM/STEM technology will have an increasing impact on frontier nanoscale research.

Infrared absorptivities of transition metals at room and liquid-helium temperatures.

NASA Technical Reports Server (NTRS)

Jones, M. C.; Palmer, D. C.; Tien, C. L.

1972-01-01

Evaluation of experimental data concerning the normal spectral absorptivities of the transition metals, nickel, iron, platinum, and chromium, at both room and liquid-helium temperatures in the wavelength range from 2.5 to 50 microns. The absorptivities were derived from reflectivity measurements made relative to a room-temperature vapor-deposited gold reference mirror. The absorptivity of the gold reference mirror was measured calorimetrically, by use of infrared laser sources. Investigation of various methods of sample-surface preparation resulted in the choice of a vacuum-annealing process as the final stage. The experimental results are discussed on the basis of the anomalous-skin-effect theory modified for multiple conduction bands. As predicted, the results approach a single-band model toward the longer wavelengths. Agreement between theory and experiment is considerably improved by taking into account the modification of the relaxation time due to the photon-electron-phonon interaction proposed by Holstein (1954) and Gurzhi (1958); but, particularly at helium temperatures, the calculated curve is consistently below the experimental results.

Performance of the dark energy camera liquid nitrogen cooling system

NASA Astrophysics Data System (ADS)

Cease, H.; Alvarez, M.; Alvarez, R.; Bonati, M.; Derylo, G.; Estrada, J.; Flaugher, B.; Flores, R.; Lathrop, A.; Munoz, F.; Schmidt, R.; Schmitt, R. L.; Schultz, K.; Kuhlmann, S.; Zhao, A.

2014-01-01

The Dark Energy Camera, the Imager and its cooling system was installed onto the Blanco 4m telescope at the Cerro Tololo Inter-American Observatory in Chile in September 2012. The imager cooling system is a LN2 two-phase closed loop cryogenic cooling system. The cryogenic circulation processing is located off the telescope. Liquid nitrogen vacuum jacketed transfer lines are run up the outside of the telescope truss tubes to the imager inside the prime focus cage. The design of the cooling system along with commissioning experiences and initial cooling system performance is described. The LN2 cooling system with the DES imager was initially operated at Fermilab for testing, then shipped and tested in the Blanco Coudé room. Now the imager is operating inside the prime focus cage. It is shown that the cooling performance sufficiently cools the imager in a closed loop mode, which can operate for extended time periods without maintenance or LN2 fills.

Emergency relief venting of the infrared telescope liquid helium dewar, second edition

NASA Technical Reports Server (NTRS)

Urban, E. W.

1981-01-01

An updated analysis is made of the emergency relief venting of the liquid helium dewar of the Spacelab 2 Infrared Telescope experiment in the event of a massive failure of the dewar guard vacuum. Such a failure, resulting from a major accident, could cause rapid heating and pressurization of the liquid helium in the dewar and lead to relief venting through the emergency relief system. The heat input from an accident is estimated for various fluid conditions in the dewar and the relief process considered as it takes place through one or both of the emergency relief paths. It was previously assumed that the burst diaphragms in the dewar relief paths would rupture at a pressure of 65 psi differential or 4.4 atmospheres. In fact, it has proved necessary to use burst diaphragms in the dewar which rupture at 115 psid or 7.8 atmospheres. An analysis of this case was carried out and shows that when the high pressure diaphragm rupture occurs, the dewar pressure falls within 8 s to below the 4.4 atmospheres for which the original analysis was performed, and thereafter it remains below that level.

Note: control of liquid helium supply to cryopanels of Kolkata superconducting cyclotron.

PubMed

Bhattacharyya, T K; Pal, G

2015-02-01

The Kolkata superconducting cyclotron utilises liquid helium to cool the main magnet niobium-titanium (NbTi) coil and the cryopanels. Three liquid helium cooled cryopanels, placed inside the dees of the radio-frequency system, maintain the high vacuum in the acceleration region of the superconducting cyclotron. The small cryostat placed inside the cryogenic distribution manifold located at the basement of the superconducting cyclotron building supplies liquid helium in parallel branches to three cold heads, used for cooling their associated cryopanels. The level in the cryostat has to be maintained at an optimum value to ensure uninterrupted flow of liquid helium to these three cold heads. This paper describes the transfer function of the overall system, its tuning parameters, and discusses the actual control of cryostat level by using these parameters.

Ionic liquids as solvents for Čerenkov counting and the effect of a wavelength shifter.

PubMed

Mirenda, M; Rodrigues, D; Ferreyra, C; Arenillas, P; Sarmiento, G P; Krimer, N; Japas, M L

2018-04-01

We study the wavelength shift of the Čerenkov light - generated in the ionic liquid (BMIMCl) - caused by the addition of the highly fluorescent ionic liquid (BMIMHPTS). 18 F and 32 P efficiencies increases up to 124% and 14%, respectively, compared with the values obtained with pure BMIMCl. With this improvement, ionic liquid mixtures become a good alternative - when using the TDCR-Cherenkov technique - to standardize radionuclides having electron emissions energies close to the threshold energy in water (∼ 260keV). As an advantage compared with other solvents, the Ionic liquid mixture can be reused, in the case of short-lived radionuclides, by simply removing all water content in a vacuum oven. Copyright © 2017 Elsevier Ltd. All rights reserved.

Taylor Instability of Incompressible Liquids

DOE R&D Accomplishments Database

Fermi, E.; von Neumann, J.

1955-11-01

A discussion is presented in simplified form of the problem of the growth of an initial ripple on the surface of an incompressible liquid in the presence of an acceleration, g, directed from the outside into the liquid. The model is that of a heavy liquid occupying at t = 0 the half space above the plane z = 0, and a rectangular wave profile is assumed. The theory is found to represent correctly one feature of experimental results, namely the fact that the half wave of the heavy liquid into the vacuum becomes rapidly narrower while the half wave pushing into the heavy liquid becomes more and more blunt. The theory fails to account for the experimental results according to which the front of the wave pushing into the heavy liquid moves with constant velocity. The case of instability at the boundary of 2 fluids of different densities is also explored. Similar results are obtained except that the acceleration of the heavy liquid into the light liquid is reduced.

Excitation of vacuum ultraviolet spectra of krypton in a cooled gas discharge

NASA Astrophysics Data System (ADS)

Gerasimov, Gennadii N.; Krylov, Boris E.; Hallin, Reinhold

1995-08-01

Results are presented on the experimental study of VUV spectra of krypton excited by a dc discharge in a capillary tube with the wall cooled to the temperature of liquid nitrogen. We studied the 120-200 nm spectral region corresponding to the transitions between the dimer lowest excited states and the weakly bound ground state, 1u, 0u+ yields 0g+. Electron impact, transferring dimers from the ground state into the excited state, is shown to be an efficient excitation mechanism in the 50-650 Torr and the 10-50 mA pressure and current ranges. The spectra obtained and the calculations made corroborate the high rate of this process.

Thermocapillary convection of melts and its role in laser-plasma synthesis and laser-induced amorphism

NASA Astrophysics Data System (ADS)

Uglov, A. A.; Smurov, I. Iu.; Gus'kov, A. G.; Semakhin, S. A.

1987-06-01

The role of thermocapillary convection in mass transfer processes in melts is investigated analytically and experimentally using vacuum-arc melted Ni63-Ta37 and Cu50-Zr50 alloys. It is shown that thermocapillary convection not only leads to the transfer of alloying components to the deeper layers of the melt but also may produce, in certain cases, a significant temperature redistribution in the liquid phase. Convective transfer dominates over conduction when the product of Re and Pr is greater than 1. In the experiments, the structure of the amorphous and crystalline layers in the solidified alloys is found to be in qualitative agreement with the structure of a thermocapillary vortex.

First Results of the Testing of the Liquid Gallium Jet Limiter Concept for ISTTOK

NASA Astrophysics Data System (ADS)

Gomes, R. B.; Fernandes, H.; Silva, C.; Borba, D.; Carvalho, B.; Varandas, C.; Lielausis, O.; Klyukin, A.; Platacis, E.; Mikelsons, A.; Platnieks, I.

2006-12-01

The use of liquid metals as plasma facing components in tokamaks has recently experienced a renewed interest stimulated by their advantages to the development of a fusion reactor. Liquid metals have been proposed to solve problems related to the erosion and neutronic activation of solid walls submitted to high power loads allowing an efficient heat exhaustion from fusion devices. Presently the most promising materials are Lithium and Gallium. ISTTOK, a small size tokamak, will be used to test the behavior of a liquid Gallium jet in the vacuum chamber and its influence on the plasma. This paper presents a description of the conceived setup as well as experimental results. The liquid Gallium jet is generated by hydrostatic pressure and injected in a radial position close to a moveable stainless steel limiter. Both the jet and the limiter positions are variable allowing for a controlled exposure of the liquid Gallium to the edge plasma. The main components of the Gallium loop are a MHD pump, the liquid metal injector and a filtering system. The MHD pump is of the induction type, based on rotating permanent magnets. The injector is build from a ¼″ stainless steel pipe ended by a shaping nozzle. A setup has been developed to introduce oxide-free Gallium inside the loop's main supply tank. Raw liquid metal is placed inside a chamber heated and degassed under high vacuum while clean Gallium is extracted from the main body of the liquefied metal. Prior to installation on the tokamak, the experimental rig has been implemented using a Pyrex tube as test chamber to investigate the stability of the Gallium jet and its break-up length for several nozzle sizes. Results are presented in this paper. This rig was also useful to assess the behavior of the overall implemented apparatus.

Photoemission and photoionization time delays and rates

PubMed Central

Gallmann, L.; Jordan, I.; Wörner, H. J.; Castiglioni, L.; Hengsberger, M.; Osterwalder, J.; Arrell, C. A.; Chergui, M.; Liberatore, E.; Rothlisberger, U.; Keller, U.

2017-01-01

Ionization and, in particular, ionization through the interaction with light play an important role in fundamental processes in physics, chemistry, and biology. In recent years, we have seen tremendous advances in our ability to measure the dynamics of photo-induced ionization in various systems in the gas, liquid, or solid phase. In this review, we will define the parameters used for quantifying these dynamics. We give a brief overview of some of the most important ionization processes and how to resolve the associated time delays and rates. With regard to time delays, we ask the question: how long does it take to remove an electron from an atom, molecule, or solid? With regard to rates, we ask the question: how many electrons are emitted in a given unit of time? We present state-of-the-art results on ionization and photoemission time delays and rates. Our review starts with the simplest physical systems: the attosecond dynamics of single-photon and tunnel ionization of atoms in the gas phase. We then extend the discussion to molecular gases and ionization of liquid targets. Finally, we present the measurements of ionization delays in femto- and attosecond photoemission from the solid–vacuum interface. PMID:29308414

Study on the Removal of Gases in RH Refining Progress through Experiments Using Vacuum Induction Furnace

NASA Astrophysics Data System (ADS)

Niu, Deliang; Liu, Qingcai; Wang, Zhu; Ren, Shan; Lan, Yuanpei; Xu, Minren

Removal of gas is the major function of RH degasser. To optimize the RH refining craft in Chongqing Iron and Steel Co. Ltd, the degassing effect of RH degasser at different degrees of vacuum was investigated using a vacuum induction furnace. In addition, the effect of processing time on the gas content dissolved in molten steel was also studied. The results showed that degree of vacuum was one of the important factors that determined the degassing efficiency in RH refining process. High vacuum degree is helpful in the removal of gas, especially in the removal of [H] dissolved in molten steel. The processing time could be reduced from 25-30 min to 15 minutes and gas content could also meet the demand of RH refining.

Failure of non-vacuum steam sterilization processes for dental handpieces.

PubMed

Winter, S; Smith, A; Lappin, D; McDonagh, G; Kirk, B

2017-12-01

Dental handpieces are used in critical and semi-critical operative interventions. Although some dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0.8-2.3 mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions. To identify the extent of sterilization failure in dental handpieces using a non-vacuum process. In-vitro and in-vivo investigations were conducted on widely used UK bench-top steam sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM; dataloggers), chemical indicator (CI), and biological indicator (BI) methods. All three methods of assessing achievement of sterility within dental handpieces that had been exposed to non-vacuum sterilization conditions demonstrated a significant number of failures [CI: 8/3024 (fails/no. of tests); BI: 15/3024; TM: 56/56] compared to vacuum sterilization conditions (CI: 2/1944; BI: 0/1944; TM: 0/36). The dental handpiece most likely to fail sterilization in the non-vacuum process was the surgical handpiece. Non-vacuum sterilizers located in general dental practice had a higher rate of sterilization failure (CI: 25/1620; BI: 32/1620; TM: 56/56) with no failures in vacuum process. Non-vacuum downward/gravity displacement, type N steam sterilizers are an unreliable method for sterilization of dental handpieces in general dental practice. The handpiece most likely to fail sterilization is the type most frequently used for surgical interventions. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Particle monitoring and control in vacuum processing equipment

NASA Astrophysics Data System (ADS)

Borden, Peter G., Dr.; Gregg, John

1989-10-01

Particle contamination during vacuum processes has emerged as the largest single source of yield loss in VLSI manufacturing. While a number of tools have been available to help understand the sources and nature of this contamination, only recently has it been possible to monitor free particle levels within vacuum equipment in real-time. As a result, a better picture is available of how particle contamination can affect a variety of processes. This paper reviews some of the work that has been done to monitor particles in vacuum loadlocks and in processes such as etching, sputtering and ion implantation. The aim has been to make free particles in vacuum equipment a measurable process parameter. Achieving this allows particles to be controlled using statistical process control. It will be shown that free particle levels in load locks correlate to wafer surface counts, device yield and process conditions, but that these levels are considerable higher during production than when dummy wafers are run to qualify a system. It will also be shown how real-time free particle monitoring can be used to monitor and control cleaning cycles, how major episodic events can be detected, and how data can be gathered in a format suitable for statistical process control.

Development of HgCdSe for Third Generation Focal Plane Arrays using Molecular Beam Epitaxy

DTIC Science & Technology

2013-08-01

quartz ampoules. Prior to the anneal, the quartz ampoules were etched in HF, pumped out to a vacuum of ~10 -5 Torr with a series of scroll and...and pumped down with a scroll pump to ≤10 -3 Torr. The load-lock was then switched from the scroll pump to a sorption pump cooled with liquid...focused on regions of (a) Ga 2p, (b) Sb 3d, (c) Sb 4d and Ga 3d, and (d) after annealing without atomic hydrogen (under vacuum ) at 400 °C for 30

Cryogenic Vacuum Insulation for Vessels and Piping

NASA Technical Reports Server (NTRS)

Kogan, A.; Fesmire, J.; Johnson, W.; Minnick, J.

2010-01-01

Cryogenic vacuum insulation systems, with proper materials selection and execution, can offer the highest levels of thermal performance. Three areas of consideration are vital to achieve the optimum result: materials, representative test conditions, and engineering approach for the particular application. Deficiency in one of these three areas can prevent optimum performance and lead to severe inefficiency. Materials of interest include micro-fiberglass, multilayer insulation, and composite arrangements. Cylindrical liquid nitrogen boil-off calorimetry methods were used. The need for standard thermal conductivity data is addressed through baseline testing. Engineering analysis and design factors such as layer thickness, density, and practicality are also considered.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masuda, Takuya; PRESTO, Japan Science and Technology Agency; Yoshikawa, Hideki

In situ electrochemical X-ray photoelectron spectroscopy (XPS) apparatus, which allows XPS at solid/liquid interfaces under potential control, was constructed utilizing a microcell with an ultra-thin Si membrane, which separates vacuum and a solution. Hard X-rays from a synchrotron source penetrate into the Si membrane surface exposed to the solution. Electrons emitted at the Si/solution interface can pass through the membrane and be analyzed by an analyzer placed in vacuum. Its operation was demonstrated for potential-induced Si oxide growth in water. Effect of potential and time on the thickness of Si and Si oxide layers was quantitatively determined at sub-nanometer resolution.

Effect of drying methods with the application of vacuum microwaves on the bioactive compounds, color, and antioxidant activity of strawberry fruits.

PubMed

Wojdyło, Aneta; Figiel, Adam; Oszmiański, Jan

2009-02-25

The objective of this study was to evaluate the application of vacuum-microwave drying (240, 360, and 480 W) in the production process of dehydrated strawberry and to compare and contrast the quality of these dehydrated strawberries in terms of their polyphenol compounds, concentration of some heat liable components, and color to that of freeze-dried, convective, and vacuum-dried strawberry. Thus, the effect of vacuum-microwave drying and other drying methods on the antioxidant activity of berries was evaluated. Whole fresh and dried fruits were assessed for phenolics (anthocyanins, flavanols, hydroxycinnamic acids, and flavonols), ascorbic acid, and antioxidant activity (all parameters were calculated on a dry matter basis). Analysis of data shows that ellagic acid and flavanol changes were affected by drying techniques and cultivar. Drying destroyed anthocyanins, flavanols, and ascorbic acid, and there was a significant decrease in antioxidant activity. The most striking result was that conventional and vacuum drying decreased antioxidant activity in both cultivars, whereas contradictory results were found for vacuum-microwave processed strawberry. This study has demonstrated that vacuum-microwave drying, especially at 240 W, can produce high-quality products, with the additional advantage of reduced processing times, compared to other processes such as freeze-drying.

Generation of Subsurface Voids, Incubation Effect, and Formation of Nanoparticles in Short Pulse Laser Interactions with Bulk Metal Targets in Liquid: Molecular Dynamics Study

PubMed Central

2017-01-01

The ability of short pulse laser ablation in liquids to produce clean colloidal nanoparticles and unusual surface morphology has been employed in a broad range of practical applications. In this paper, we report the results of large-scale molecular dynamics simulations aimed at revealing the key processes that control the surface morphology and nanoparticle size distributions by pulsed laser ablation in liquids. The simulations of bulk Ag targets irradiated in water are performed with an advanced computational model combining a coarse-grained representation of liquid environment and an atomistic description of laser interaction with metal targets. For the irradiation conditions that correspond to the spallation regime in vacuum, the simulations predict that the water environment can prevent the complete separation of the spalled layer from the target, leading to the formation of large subsurface voids stabilized by rapid cooling and solidification. The subsequent irradiation of the laser-modified surface is found to result in a more efficient ablation and nanoparticle generation, thus suggesting the possibility of the incubation effect in multipulse laser ablation in liquids. The simulations performed at higher laser fluences that correspond to the phase explosion regime in vacuum reveal the accumulation of the ablation plume at the interface with the water environment and the formation of a hot metal layer. The water in contact with the metal layer is brought to the supercritical state and provides an environment suitable for nucleation and growth of small metal nanoparticles from metal atoms emitted from the hot metal layer. The metal layer itself has limited stability and can readily disintegrate into large (tens of nanometers) nanoparticles. The layer disintegration is facilitated by the Rayleigh–Taylor instability of the interface between the higher density metal layer decelerated by the pressure from the lighter supercritical water. The nanoparticles emerging from the layer disintegration are rapidly cooled and solidified due to the interaction with water environment, with a cooling rate of ∼2 × 1012 K/s observed in the simulations. The computational prediction of two distinct mechanisms of nanoparticle formation yielding nanoparticles with different characteristic sizes provides a plausible explanation for the experimental observations of bimodal nanoparticle size distributions in laser ablation in liquids. The ultrahigh cooling and solidification rates suggest the possibility for generation of nanoparticles featuring metastable phases and highly nonequilibrium structures. PMID:28798858

Vacuum Studies of a Prototype Composite Coil Dewar for HTSC Transformers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwenterly, S W; Zhang, Y.; Pleva, E. F.

Oak Ridge National Laboratory (ORNL) is collaborating with Waukesha Electric Systems (WES) to develop a high-temperature superconducting (HTSC) utility power transformer with primary and secondary coils cooled by liquid nitrogen. Since the vacuum-insulated cryogenic coil dewar surrounds the magnetic core limb and cannot form a shorted turn, non-conductive materials are required. Two test vessels and a small prototype dewar have been fabricated by Scorpius Space Launch Company with epoxy/fiberglass composites, using their proprietary PRESSURMAXX vessel technology. The effects of pumping time, bakeout temperature, and cryogenic vessel temperature on vacuum outgassing rates have been investigated. Outgassing rates of the individual materialsmore » used in vessel construction have also been measured. The results will be scaled up to determine the required pumping capacity for a full-size 25-MVA commercial transformer dewar.« less

Thermal conductivity of aerogel blanket insulation under cryogenic-vacuum conditions in different gas environments

NASA Astrophysics Data System (ADS)

E Fesmire, J.; Ancipink, J. B.; Swanger, A. M.; White, S.; Yarbrough, D.

2017-12-01

Thermal conductivity of low-density materials in thermal insulation systems varies dramatically with the environment: cold vacuum pressure, residual gas composition, and boundary temperatures. Using a reference material of aerogel composite blanket (reinforcement fibers surrounded by silica aerogel), an experimental basis for the physical heat transmission model of aerogel composites and other low-density, porous materials is suggested. Cryogenic-vacuum testing between the boundary temperatures of 78 K and 293 K is performed using a one meter cylindrical, absolute heat flow calorimeter with an aerogel blanket specimen exposed to different gas environments of nitrogen, helium, argon, or CO2. Cold vacuum pressures include the full range from 1×10-5 torr to 760 torr. The soft vacuum region, from about 0.1 torr to 10 torr, is complex and difficult to model because all modes of heat transfer - solid conduction, radiation, gas conduction, and convection - are significant contributors to the total heat flow. Therefore, the soft vacuum tests are emphasized for both heat transfer analysis and practical thermal data. Results for the aerogel composite blanket are analyzed and compared to data for its component materials. With the new thermal conductivity data, future applications of aerogel-based insulation systems are also surveyed. These include Mars exploration and surface systems in the 5 torr CO2 environment, field joints for vacuum-jacketed cryogenic piping systems, common bulkhead panels for cryogenic tanks on space launch vehicles, and liquid hydrogen cryofuel systems with helium purged conduits or enclosures.

Troubleshooting crude vacuum tower overhead ejector systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lines, J.R.; Frens, L.L.

1995-03-01

Routinely surveying tower overhead vacuum systems can improve performance and product quality. These vacuum systems normally provide reliable and consistent operation. However, process conditions, supplied utilities, corrosion, erosion and fouling all have an impact on ejector system performance. Refinery vacuum distillation towers use ejector systems to maintain tower top pressure and remove overhead gases. However, as with virtually all refinery equipment, performance may be affected by a number of variables. These variables may act independently or concurrently. It is important to understand basic operating principles of vacuum systems and how performance is affected by: utilities, corrosion and erosion, fouling, andmore » process conditions. Reputable vacuum-system suppliers have service engineers that will come to a refinery to survey the system and troubleshoot performance or offer suggestions for improvement. A skilled vacuum-system engineer may be needed to diagnose and remedy system problems. The affect of these variables on performance is discussed. A case history is described of a vacuum system on a crude tower in a South American refinery.« less

Clean amine solvents economically and online

DOE Office of Scientific and Technical Information (OSTI.GOV)

Price, J.; Burns, D.

1995-08-01

Using electrodialysis technology to clean amine solvents is economically competitive with traditional change-out or ``bleed and feed`` methods, even for small systems, because a unit shutdown is not necessary to perform the process. Electrodialysis also has advantages over other online cleanup processes like ion exchange and vacuum reclamation. Off gases and olefinic and saturate liquefied petroleum gas (LPG) streams generated during operation of fluid catalytic crackers (FCC), cokers and other refinery processing equipment must be treated to remove undesirable components like hydrogen sulfide and carbon dioxide before they can be sold or used in downstream processes. At an Arkansas City,more » Kansas, refinery, a classic amine-based chemical absorbent system is used for this purpose. It comprises two absorbing contacts for gas and two for liquids. The system is charged with an N-methyldiethanolamine (MDEA)-based product that selectively absorbs contaminants. Amine is regenerated by removing contaminants with steam stripping. Lean amine is then recirculated to the absorbers. This case history demonstrates the effectiveness of electrodialysis technology for contaminant removal.« less

Near-Net-Shape Processing of Sintered Fibrous Ceramics Achieved

NASA Technical Reports Server (NTRS)

Angel, Paul W.

2000-01-01

A variety of sintered fibrous ceramic (SFC) materials have been developed over the last 50 years as thermal barrier materials for reentry applications. SFC materials typically exhibit very low thermal conductivities combined with low densities and good thermal stability up to 2500 F. These materials have flown successfully on the space shuttle orbiters since the 1960's. More recently, the McDonnell Douglas Corporation successfully used SFC tiles as a heat shield on the underside of its DC X test vehicle. For both of these applications, tiles are machined from blocks of a specific type of SFC called an alumina-enhanced thermal barrier (AETB). The sizes of these blocks have been limited by the manufacturing process. In addition, as much as 80 to 90 percent of the material can be lost during the machining of tiles with significant amounts of curvature. To address these problems, the NASA Glenn Research Center at Lewis Field entered a cooperative contract with the Boeing Company to develop a vacuum-assisted forming process that can produce large (approximately 4 square feet), severely contoured panels of AETB while saving costs in comparison to the conventional cast-and-machine billet process. For shuttle use, AETB is slurry cast, drained, and fired to form square billets conforming to the shape of the filtration box. The billets are then cut into tiles of the appropriate size for thermally protecting the space shuttle. Processing techniques have limited the maximum size of AETB billets to 21.5 square inches by 6.5-in. thick, but the space shuttles use discrete heat shield tiles no more than 8 to 12 square inches. However, in other applications, large, complex shapes are needed, and the tiling approach is undesirable. For such applications, vacuum-assisted forming can produce large parts with complex shapes while reducing machining waste and eliminating cemented joints between bonded billets. Because it allows contoured shapes to be formed, material utilization is inherently high. Initial estimates show that the amount of material lost during machining can be reduced by 50 percent or more. In addition, a fiber alignment favorable for minimum heat transfer is maintained for all panel shapes since the fibers are aligned parallel to the contoured surface of the forming tool or mold. The vacuum-assisted forming process can complete the entire forming operation in a matter of minutes and can produce multiple parts whose size is limited only by the size of the forming tool. To date, panels as large as 2 square feet have been demonstrated The vacuum-assisted forming process starts with the fabrication of a permeable forming tool, or mold, with the proper part contour. This reusable tool is mounted over an internal rib support structure, as depicted in the diagram, such that a vacuum can be pulled on the bottom portion of the tool. AETB slurry is then poured over and around the tool, liquid is drawn from the slurry, and the part forms over the tool surface. The part is then dried, fired, and finished machined. Future plans include an evaluation of the need for additional coatings and surface-toughness treatments to extend the durability and performance of this material.

Evaporation of Lennard-Jones fluids.

PubMed

Cheng, Shengfeng; Lechman, Jeremy B; Plimpton, Steven J; Grest, Gary S

2011-06-14

Evaporation and condensation at a liquid/vapor interface are ubiquitous interphase mass and energy transfer phenomena that are still not well understood. We have carried out large scale molecular dynamics simulations of Lennard-Jones (LJ) fluids composed of monomers, dimers, or trimers to investigate these processes with molecular detail. For LJ monomers in contact with a vacuum, the evaporation rate is found to be very high with significant evaporative cooling and an accompanying density gradient in the liquid domain near the liquid/vapor interface. Increasing the chain length to just dimers significantly reduces the evaporation rate. We confirm that mechanical equilibrium plays a key role in determining the evaporation rate and the density and temperature profiles across the liquid/vapor interface. The velocity distributions of evaporated molecules and the evaporation and condensation coefficients are measured and compared to the predictions of an existing model based on kinetic theory of gases. Our results indicate that for both monatomic and polyatomic molecules, the evaporation and condensation coefficients are equal when systems are not far from equilibrium and smaller than one, and decrease with increasing temperature. For the same reduced temperature T/T(c), where T(c) is the critical temperature, these two coefficients are higher for LJ dimers and trimers than for monomers, in contrast to the traditional viewpoint that they are close to unity for monatomic molecules and decrease for polyatomic molecules. Furthermore, data for the two coefficients collapse onto a master curve when plotted against a translational length ratio between the liquid and vapor phase.

Theoretical Performance of Liquid Hydrogen with Liquid Oxygen as a Rocket Propellant

NASA Technical Reports Server (NTRS)

Gordon, Sanford; McBride, Bonnie J.

1959-01-01

Theoretical rocket performance for both equilibrium and frozen composition during expansion was calculated for the propellant combination liquid hydrogen and liquid oxygen at four chamber pressures (60, 150, 300, and 600 lb/sq in. abs) and a wide range of pressure ratios (1 to 4000) and oxidant-fuel ratios (1.190 to 39.683). Data are given to estimate performance parameters at chamber pressures other than those for which data are tabulated. The parameters included are specific impulse, specific impulse in vacuum, combustion-chamber temperature, nozzle-exit temperature, molecular weight, molecular-weight derivatives, characteristic velocity, coefficient of thrust, ratio of nozzle-exit area to throat area, specific heat at constant pressure, isentropic exponent, viscosity, thermal conductivity, Mach number, and equilibrium gas compositions.

Electron microscopy of whole cells in liquid with nanometer resolution

PubMed Central

de Jonge, N.; Peckys, D. B.; Kremers, G. J.; Piston, D. W.

2009-01-01

Single gold-tagged epidermal growth factor (EGF) molecules bound to cellular EGF receptors of fixed fibroblast cells were imaged in liquid with a scanning transmission electron microscope (STEM). The cells were placed in buffer solution in a microfluidic device with electron transparent windows inside the vacuum of the electron microscope. A spatial resolution of 4 nm and a pixel dwell time of 20 μs were obtained. The liquid layer was sufficiently thick to contain the cells with a thickness of 7 ± 1 μm. The experimental findings are consistent with a theoretical calculation. Liquid STEM is a unique approach for imaging single molecules in whole cells with significantly improved resolution and imaging speed over existing methods. PMID:19164524

Reusable crucible for containing corrosive liquids

DOEpatents

de Pruneda, Jean A. H.

1995-01-01

A reusable, non-wetting, corrosion-resistant material suitable for containment of corrosive liquids is formed of a tantalum or tantalum alloy substrate that is permeated with carbon atoms. The substrate is carburized to form surface layers of TaC and Ta.sub.2 C, and then is heated at high temperature under vacuum until the carbon atoms in the carbide layers diffuse throughout the substrate to form a solid solution of carbon atoms randomly interspersed in the tantalum or tantalum alloy lattice.

Reusable crucible for containing corrosive liquids

DOEpatents

Pruneda, J.A.H. de.

1995-01-24

A reusable, non-wetting, corrosion-resistant material suitable for containment of corrosive liquids is formed of a tantalum or tantalum alloy substrate that is permeated with carbon atoms. The substrate is carburized to form surface layers of TaC and Ta[sub 2]C, and then is heated at high temperature under vacuum until the carbon atoms in the carbide layers diffuse throughout the substrate to form a solid solution of carbon atoms randomly interspersed in the tantalum or tantalum alloy lattice. 10 figures.

Test of SensL SiPM coated with NOL-1 wavelength shifter in liquid xenon

NASA Astrophysics Data System (ADS)

Akimov, D. Yu.; Belov, V. A.; Borshchev, O. V.; Burenkov, A. A.; Grishkin, Yu. L.; Karelin, A. K.; Kuchenkov, A. V.; Martemiyanov, A. N.; Ponomarenko, S. A.; Simakov, G. E.; Stekhanov, V. N.; Surin, N. M.; Timoshin, V. S.; Zeldovich, O. Ya.

2017-05-01

A SensL MicroFC-SMT-60035 6×6 mm2 silicon photo-multiplier coated with a NOL-1 wavelength shifter have been tested in the liquid xenon to detect the 175-nm scintillation light. For comparison, a Hamamatsu vacuum ultraviolet sensitive MPPC VUV3 3×3 mm2 was tested under the same conditions. The photodetection efficiency of 13.1 ± 2.5% and 6.0 ± 1.0%, correspondingly, is obtained.

Analysis of the free-fall behavior of liquid-metal drops in a gaseous atmosphere

NASA Technical Reports Server (NTRS)

Mccoy, J. Kevin; Markworth, Alan J.; Collings, E. W.; Brodkey, Robert S.

1987-01-01

The free-fall of a liquid-metal drop and heat transfer from the drop to its environment are described for both a gaseous atmosphere and vacuum. A simple model, in which the drop is assumed to fall rectilinearly with behavior like that of a rigid particle, is developed first, then possible causes of deviation from this behavior are discussed. The model is applied to describe solidification of drops in a drop tube. Possible future developments of the model are suggested.

Electrokinetic detection for X-ray spectra of weakly interacting liquids: n-decane and n-nonane.

PubMed

Lam, Royce K; Shih, Orion; Smith, Jacob W; Sheardy, Alex T; Rizzuto, Anthony M; Prendergast, David; Saykally, Richard J

2014-06-21

The introduction of liquid microjets into soft X-ray absorption spectroscopy enabled the windowless study of liquids by this powerful atom-selective high vacuum methodology. However, weakly interacting liquids produce large vapor backgrounds that strongly perturb the liquid signal. Consequently, solvents (e.g., hydrocarbons, ethers, ketones, etc.) and solutions of central importance in chemistry and biology have been inaccessible by this technology. Here we describe a new detection method, upstream detection, which greatly reduces the vapor phase contribution to the X-ray absorption signal while retaining important advantages of liquid microjet sample introduction (e.g., minimal radiation damage). The effectiveness of the upstream detection method is demonstrated in this first study of room temperature liquid hydrocarbons: n-nonane and n-decane. Good agreement with first principles' calculations indicates that the eXcited electron and Core Hole theory adequately describes the subtle interactions in these liquids that perturb the electronic structure of the unoccupied states probed in core-level experiments.

A novel X-ray diffractometer for studies of liquid-liquid interfaces.

PubMed

Murphy, Bridget M; Greve, Matthais; Runge, Benjamin; Koops, Christian T; Elsen, Annika; Stettner, Jochim; Seeck, Oliver H; Magnussen, Olaf M

2014-01-01

The study of liquid-liquid interfaces with X-ray scattering methods requires special instrumental considerations. A dedicated liquid surface diffractometer employing a tilting double-crystal monochromator in Bragg geometry has been designed. This diffractometer allows reflectivity and grazing-incidence scattering measurements of an immobile mechanically completely decoupled liquid sample, providing high mechanical stability. The available energy range is from 6.4 to 29.4 keV, covering many important absorption edges. The instrument provides access in momentum space out to 2.54 Å(-1) in the surface normal and out to 14.8 Å(-1) in the in-plane direction at 29.4 keV. Owing to its modular design the diffractometer is also suitable for heavy apparatus such as vacuum chambers. The instrument performance is described and examples of X-ray reflectivity studies performed under in situ electrochemical control and on biochemical model systems are given.

Non-toxic liquid scintillators with high light output based on phenyl-substituted siloxanes

NASA Astrophysics Data System (ADS)

Dalla Palma, M.; Carturan, S. M.; Degerlier, M.; Marchi, T.; Cinausero, M.; Gramegna, F.; Quaranta, A.

2015-04-01

The work describes the development of a new class of liquid scintillators based on polysiloxane liquid compounds. These materials are characterized by low toxicity, chemical inertness, very low volatility and low flammability, allowing their use without concerns even at high temperatures in vacuum. In this view different polysiloxane based liquids have been tested, with variable content and distribution of phenyl lateral substituents and added with suitable dyes, namely 2,5-diphenyloxazole (PPO) and Lumogen Violet (LV). Absorption and fluorescence spectroscopy have been used in order to study the emission feature of the various compounds and to investigate the spectral matching between siloxane solvents and dissolved primary dyes. Scintillation efficiency towards 60Co and 137Cs gamma rays, relative to commercial liquid scintillator (EJ-309), has been measured and the results have been related to the energy transfer and energy migration mechanism from monomer and excimer forming sites in liquid siloxanes.

Thermal Performance Comparison of Glass Microsphere and Perlite Insulation Systems for Liquid Hydrogen Storage Tanks

NASA Astrophysics Data System (ADS)

Sass, J. P.; Fesmire, J. E.; Nagy, Z. F.; Sojourner, S. J.; Morris, D. L.; Augustynowicz, S. D.

2008-03-01

A technology demonstration test project was conducted by the Cryogenics Test Laboratory at the Kennedy Space Center (KSC) to provide comparative thermal performance data for glass microspheres, referred to as bubbles, and perlite insulation for liquid hydrogen tank applications. Two identical 1/15th scale versions of the 3,200,000 liter spherical liquid hydrogen tanks at Launch Complex 39 at KSC were custom designed and built to serve as test articles for this test project. Evaporative (boil-off) calorimeter test protocols, including liquid nitrogen and liquid hydrogen, were established to provide tank test conditions characteristic of the large storage tanks that support the Space Shuttle launch operations. This paper provides comparative thermal performance test results for bubbles and perlite for a wide range of conditions. Thermal performance as a function of cryogenic commodity (nitrogen and hydrogen), vacuum pressure, insulation fill level, tank liquid level, and thermal cycles will be presented.

Use of osmotic dehydration to improve fruits and vegetables quality during processing.

PubMed

Maftoonazad, Neda

2010-11-01

Osmotic treatment describes a preparation step to further processing of foods involving simultaneous transient moisture loss and solids gain when immersing in osmotic solutions, resulting in partial drying and improving the overall quality of food products. The different aspects of the osmotic dehydration (OD) technology namely the solutes employed, solutions characteristics used, process variables influence, as well as, the quality characteristics of the osmodehydrated products will be discussed in this review. As the process is carried out at mild temperatures and the moisture is removed by a liquid diffusion process, phase change that would be present in the other drying processes will be avoided, resulting in high quality products and may also lead to substantial energy savings. To optimize this process, modeling of the mass transfer phenomenon can improve high product quality. Several techniques such as microwave heating, vacuum, high pressure, pulsed electric field, etc. may be employed during or after osmotic treatment to enhance performance of the osmotic dehydration. Moreover new technologies used in osmotic dehydration will be discussed. Patents on osmotic dehydration of fruits and vegetables are also discussed in this article.

A NEW, SMALL DRYING FACILITY FOR WET RADIOACTIVE WASTE AND LIQUIDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oldiges, Olaf; Blenski, Hans-Juergen

2003-02-27

Due to the reason, that in Germany every Waste, that is foreseen to be stored in a final disposal facility or in a long time interim storage facility, it is necessary to treat a lot of waste using different drying technologies. In Germany two different drying facilities are in operation. The GNS Company prefers a vacuum-drying-technology and has built and designed PETRA-Drying-Facilities. In a lot of smaller locations, it is not possible to install such a facility because inside the working areas of that location, the available space to install the PETRA-Drying-Facility is too small. For that reason, GNS decidedmore » to design a new, small Drying-Facility using industrial standard components, applying the vacuum-drying-technology. The new, small Drying-Facility for wet radioactive waste and liquids is presented in this paper. The results of some tests with a prototype facility are shown in chapter 4. The main components of that new facility are described in chapter 3.« less

Zero boil-off system testing

NASA Astrophysics Data System (ADS)

Plachta, D. W.; Johnson, W. L.; Feller, J. R.

2016-03-01

Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASA's future space exploration plans due to their high specific impulse for rocket motors of upper stages. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for long duration missions. These losses can be eliminated by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and modulating the cryocooler temperature to control tank pressure. The technology being developed by NASA is the reverse turbo-Brayton cycle cryocooler and its integration to the propellant tank through a distributed cooling tubing network coupled to the tank wall. This configuration was recently tested at NASA Glenn Research Center in a vacuum chamber and cryoshroud that simulated the essential thermal aspects of low Earth orbit, its vacuum and temperature. This test series established that the active cooling system integrated with the propellant tank eliminated boil-off and robustly controlled tank pressure.

Apparatus and method for maintaining an article at a temperature that is less than the temperature of the ambient air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klett, James; Klett, Lynn

An apparatus for maintaining the temperature of an article at a temperature that is below the ambient air temperature includes an enclosure having an outer wall that defines an interior chamber for holding a volume of sealed air. An insert is disposed inside of the chamber and has a body that is made of a porous graphite foam material. A vacuum pump penetrates the outer wall and fluidly connects the sealed air in the interior chamber with the ambient air outside of the enclosure. The temperatures of the insert and article is maintained at temperatures that are below the ambientmore » air temperature when a volume of a liquid is wicked into the pores of the porous insert and the vacuum pump is activated to reduce the pressure of a volume of sealed air within the interior chamber to a pressure that is below the vapor pressure of the liquid.« less

Zero Boil-Off System Testing

NASA Technical Reports Server (NTRS)

Plachta, D. W.; Johnson, W. L.; Feller, J. R.

2015-01-01

Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASA's future space exploration plans due to their high specific impulse for rocket motors of upper stages. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for long duration missions. These losses can be eliminated by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and modulating the cryocooler temperature to control tank pressure. The technology being developed by NASA is the reverse turbo-Brayton cycle cryocooler and its integration to the propellant tank through a distributed cooling tubing network coupled to the tank wall. This configuration was recently tested at NASA Glenn Research Center in a vacuum chamber and cryoshroud that simulated the essential thermal aspects of low Earth orbit, its vacuum and temperature. This test series established that the active cooling system integrated with the propellant tank eliminated boil-off and robustly controlled tank pressure.

Nonadditivity of van der Waals forces on liquid surfaces

NASA Astrophysics Data System (ADS)

Venkataram, Prashanth S.; Whitton, Jeremy D.; Rodriguez, Alejandro W.

2016-09-01

We present an approach for modeling nanoscale wetting and dewetting of textured solid surfaces that exploits recently developed, sophisticated techniques for computing exact long-range dispersive van der Waals (vdW) or (more generally) Casimir forces in arbitrary geometries. We apply these techniques to solve the variational formulation of the Young-Laplace equation and predict the equilibrium shapes of liquid-vacuum interfaces near solid gratings. We show that commonly employed methods of computing vdW interactions based on additive Hamaker or Derjaguin approximations, which neglect important electromagnetic boundary effects, can result in large discrepancies in the shapes and behaviors of liquid surfaces compared to exact methods.

Method of retrieving a liquid sample, a suction lysimeter, a portable suction lysimeter, a lysimeter system, and a deep lysimeter

DOEpatents

Hubbell, Joel M.; Sisson, James B.

2003-08-26

A method of retrieving a liquid sample comprises providing a portable lysimeter including a semi-permeable membrane and a chamber in fluid communication with the semi-permeable membrane; making a hole at a site from which a liquid sample is desired; evacuating the chamber by applying a vacuum to the chamber; lowering the portable lysimeter into the hole; obtaining a sample in the chamber; and retrieving the lysimeter from the bore; wherein it is not necessary to backfill the bore. A portable lysimeter includes a semi-permeable member and a chamber in fluid communication with the semi-permeable membrane.

Vacuum pull down method for an enhanced bonding process

DOEpatents

Davidson, James C.; Balch, Joseph W.

1999-01-01

A process for effectively bonding arbitrary size or shape substrates. The process incorporates vacuum pull down techniques to ensure uniform surface contact during the bonding process. The essence of the process for bonding substrates, such as glass, plastic, or alloys, etc., which have a moderate melting point with a gradual softening point curve, involves the application of an active vacuum source to evacuate interstices between the substrates while at the same time providing a positive force to hold the parts to be bonded in contact. This enables increasing the temperature of the bonding process to ensure that the softening point has been reached and small void areas are filled and come in contact with the opposing substrate. The process is most effective where at least one of the two plates or substrates contain channels or grooves that can be used to apply vacuum between the plates or substrates during the thermal bonding cycle. Also, it is beneficial to provide a vacuum groove or channel near the perimeter of the plates or substrates to ensure bonding of the perimeter of the plates or substrates and reduce the unbonded regions inside the interior region of the plates or substrates.

Vacuum casting of thick polymeric films

NASA Technical Reports Server (NTRS)

Cuddihy, E. F.; Moacanin, J.

1979-01-01

Bubble formation and layering, which often plague vacuum-evaporated films, are prevented by properly regulating process parameters. Vacuum casting may be applicable to forming thick films of other polymer/solvent solutions.

Proceedings of the twenty sixth international symposium on discharges and electrical insulation in vacuum. V. 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2014-07-01

Vacuum science and technology has made vital contributions in high technology areas like space, high energy particle accelerators, plasma devices, pulse power, electronics, vacuum interrupters, thin films, melting and refining of metals/alloys, extraction and processing of advanced materials. Vacuum discharges, vacuum arc physics and technology and various applications towards vacuum interrupters, pulse power and particle accelerator are the main themes for this symposium. Papers relevant to INIS are indexed separately.

Proceedings of the twenty sixth international symposium on discharges and electrical insulation in vacuum. V. 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2014-07-01

Vacuum science and technology has made vital contributions in high technology areas like space, high energy particle accelerators, plasma devices, pulse power, electronics, vacuum interrupters, thin films, melting and refining of metals/alloys, extraction and processing of advanced materials. Vacuum discharges, vacuum arc physics and technology and various applications towards vacuum interrupters, pulse power and particle accelerator are the main themes for this symposium. Papers relevant to INIS are indexed separately.

Enhanced Photocatalytic Activity of Vacuum-activated TiO2 Induced by Oxygen Vacancies.

PubMed

Dong, Guoyan; Wang, Xin; Chen, Zhiwu; Lu, Zhenya

2018-05-01

TiO 2 (Degussa P25) photocatalysts harboring abundant oxygen vacancies (Vacuum P25) were manufactured using a simple and economic Vacuum deoxidation process. Control experiments showed that temperature and time of vacuum deoxidation had a significant effect on Vacuum P25 photocatalytic activity. After 240 min of visible light illumination, the optimal Vacuum P25 photocatalysts (vacuum deoxidation treated at 330 °C for 3 h) reach as high as 94% and 88% of photodegradation efficiency for rhodamine B (RhB) and tetracycline, respectively, which are around 4.5 and 4.9 times as that of pristine P25. The XPS, PL and EPR analyses indicated that the oxygen vacancies were produced in the Vacuum P25 during the vacuum deoxidation process. The oxygen vacancy states can produce vacancy energy level located below the conduction band minimum, which resulting in the bandgap narrowing, thus extending the photoresponse wavelength range of Vacuum P25. The positron annihilation analysis indicated that the concentrations ratio of bulk and surface oxygen vacancies could be adjusted by changing the vacuum deoxidation temperature and time. Decreasing the ratio of bulk and surface oxygen vacancies was shown to improve photogenerated electron-hole pair separation efficiency, which leads to an obvious enhancement of the visible photocatalytic activities of Vacuum P25. © 2017 The American Society of Photobiology.

Note: Control of liquid helium supply to cryopanels of Kolkata superconducting cyclotron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, T. K., E-mail: tamal@vecc.gov.in; Pal, G.

2015-02-15

The Kolkata superconducting cyclotron utilises liquid helium to cool the main magnet niobium-titanium (NbTi) coil and the cryopanels. Three liquid helium cooled cryopanels, placed inside the dees of the radio-frequency system, maintain the high vacuum in the acceleration region of the superconducting cyclotron. The small cryostat placed inside the cryogenic distribution manifold located at the basement of the superconducting cyclotron building supplies liquid helium in parallel branches to three cold heads, used for cooling their associated cryopanels. The level in the cryostat has to be maintained at an optimum value to ensure uninterrupted flow of liquid helium to these threemore » cold heads. This paper describes the transfer function of the overall system, its tuning parameters, and discusses the actual control of cryostat level by using these parameters.« less

Volatile composition and sensory profile of shiitake mushrooms as affected by drying method.

PubMed

Politowicz, Joanna; Lech, Krzysztof; Lipan, Leontina; Figiel, Adam; Carbonell-Barrachina, Ángel A

2018-03-01

One of the best preservation method for long-term storage is drying. In this work, the influence of different drying methods on aroma and sensory profile of shiitake mushroom was evaluated. The drying methods tested were: convective drying (CD), freeze-drying (FD), vacuum-microwave drying (VMD), and a combination of convective pre-drying and vacuum-microwave finish-drying (CPD-VMFD). The volatile composition of fresh and dried shiitake mushrooms was analysed by SPME, GC-MS and GC-FID, and showed the presence of 71 volatile compounds, most of them present in all dried samples but with quantitative variation. The major volatile compounds in fresh shiitake were 1-octen-3-ol (20.2%), 2-octanone (20.7%), 1,2,4-trithiolane (9.8%), and 1,2,3,5,6-pentathiepane (8.2%). Drying of shiitake mushrooms caused significant losses of C8 compounds and cyclic sulfur compounds, such as 1,2,4-trithiolane (V31) and 1,2,4,5-tetrathiane (V57). Samples dried at CD 80 °C implied a relative short drying time (120 min), had the highest contents of total volatiles (1594 μg 100 g -1 ) and cyclic sulfur compounds (e.g. V57 126 μg 100 g -1 ), and the highest intensity of most of the key positive sensory attributes, such as inner colour (7.0), fresh shiitake flavour (6.7), and sponginess (6.2). The best dehydration methods, resulting in the highest total concentrations of volatile compounds and high intensity of key sensory attributes were FD (if vacuum and liquid nitrogen facilities are available) and CD at 80 °C (for companies with vacuum and liquid nitrogen facilities). © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Low Cost Processing of Commingled Thermoplastic Composites

NASA Astrophysics Data System (ADS)

Chiasson, Matthew Lee

A low cost vacuum consolidation process has been investigated for use with commingled thermoplastic matrix composites. In particular, the vacuum consolidation behaviour of commingled polypropylene/glass fibre and commingled nylon/carbon fibre precursors were studied. Laminates were consolidated in a convection oven under vacuum pressure. During processing, the consolidation of the laminate packs was measured by use of non-contact eddy current sensors. The consolidation curves are then used to tune an empirical consolidation model. The overall quality of the resulting laminates is also discussed. Dynamic mechanical analysis, differential scanning calorimetry and mechanical tensile testing were also performed in order to determine the effects of varying processing parameters on the physical and mechanical properties of the laminates. Through this analysis, it was determined that the nylon/carbon fibre blend was not suitable for vacuum consolidation, while the polypropylene/glass fibre blend is a viable option for vacuum consolidation. The ultimate goal of this work is to provide a foundation from which low cost unmanned aerial vehicle (UAV) components can be designed and manufactured from thermoplastic matrix composites using a low cost processing technique as an alternative to traditional thermoset composite materials.

Breakdown Conditioning Chacteristics of Precision-Surface-Treatment-Electrode in Vacuum

NASA Astrophysics Data System (ADS)

Kato, Kastumi; Fukuoka, Yuji; Inagawa, Yukihiko; Saitoh, Hitoshi; Sakaki, Masayuki; Okubo, Hitoshi

Breakdown (BD) characteristics in vacuum are strongly dependent on the electrode surface condition, like the surface roughness etc. Therefore, in order to develop a high voltage vacuum circuit breaker, it is important to optimize the surface treatment process. This paper discusses about the effect of precision-surface-treatment of the electrode on breakdown conditioning characteristics under non-uniform electric field in vacuum. Experimental results reveal that the electrode surface treatment affects the conditioning process, especially the BD voltage and the BD field strength at the initial stage of the conditioning.

Application of Ferrofluids as an Acoustic Transducer Material.

DTIC Science & Technology

1979-12-04

oleic acid . The carrier is typically nonconductive, but efforts are in progress to suspend the particles in conducting liquids such as mercury or...and at lower temperature in high-vacuum applications. It has excellent chemical stability to 120*C. The carrier is bis- (2 ethylhexyl) azelate which

Boiling process modelling peculiarities analysis of the vacuum boiler

NASA Astrophysics Data System (ADS)

Slobodina, E. N.; Mikhailov, A. G.

2017-06-01

The analysis of the low and medium powered boiler equipment development was carried out, boiler units possible development directions with the purpose of energy efficiency improvement were identified. Engineering studies for the vacuum boilers applying are represented. Vacuum boiler heat-exchange processes where boiling water is the working body are considered. Heat-exchange intensification method under boiling at the maximum heat- transfer coefficient is examined. As a result of the conducted calculation studies, heat-transfer coefficients variation curves depending on the pressure, calculated through the analytical and numerical methodologies were obtained. The conclusion about the possibility of numerical computing method application through RPI ANSYS CFX for the boiling process description in boiler vacuum volume was given.

Plates for vacuum thermal fusion

DOEpatents

Davidson, James C.; Balch, Joseph W.

2002-01-01

A process for effectively bonding arbitrary size or shape substrates. The process incorporates vacuum pull down techniques to ensure uniform surface contact during the bonding process. The essence of the process for bonding substrates, such as glass, plastic, or alloys, etc., which have a moderate melting point with a gradual softening point curve, involves the application of an active vacuum source to evacuate interstices between the substrates while at the same time providing a positive force to hold the parts to be bonded in contact. This enables increasing the temperature of the bonding process to ensure that the softening point has been reached and small void areas are filled and come in contact with the opposing substrate. The process is most effective where at least one of the two plates or substrates contain channels or grooves that can be used to apply vacuum between the plates or substrates during the thermal bonding cycle. Also, it is beneficial to provide a vacuum groove or channel near the perimeter of the plates or substrates to ensure bonding of the perimeter of the plates or substrates and reduce the unbonded regions inside the interior region of the plates or substrates.

Formation of protein sub-visible particles during vacuum degassing of etanercept solutions.

PubMed

Wang, Haibin; Zheng, Hong-Jian; Wang, Zhao; Bai, Hua; Carpenter, John F; Chen, Shuqing; Fang, Wei-Jie

2014-05-01

The main purpose of this manuscript is to describe a phenomenon in which vacuum degassing a reconstituted freeze-dried fusion protein etanercept formulation caused a significant amount of protein sub-visible particles (SbVP). Physical stability of etanercept was monitored by micro-flow imaging (MFI), dynamic light scattering (DLS), size-exclusion high pressure liquid chromatography (SE-HPLC) and far- and near-ultraviolet circular dichroism (far- and near-UV CD). One potential explanation of this phenomenon is that bubble collapses when the vacuum is applied, leads to substantial heat formation, and ultimately free radical formation. Subsequently, the effect of a free-radical scavenger (ascorbic acid, AA) on SbVP formation was also evaluated. Degassing of etanercept solution by applying vacuum caused substantial increase of SbVP, as detected by MFI and DLS. However, traditional techniques such as SE-HPLC could not detect any change. The addition of free-radical scavenger had minimal effect on SbVP formation, therefore the formation of free radicals was probably not the main cause for this effect. Copyright © 2014 Elsevier B.V. All rights reserved.

Ultra-high speed visualization of the flashing instability under vacuum conditions

NASA Astrophysics Data System (ADS)

Hernández Sánchez, Jose Federico; Al-Ghamdi, Tariq; Thoroddsen, Sigurdur T.

2017-11-01

We investigated experimentally the flashing instability of a jet of perfluoro-n-hexane (PFnH) released into a low-pressure environment. Using a ultra-high speed camera we observed the jet fragmentation occurring close to the nozzle. Using a fixed total driving pressure, we decreased systematically the vacuum pressure, investigating the transition from a laminar jet to a fully flashing jet. Our high temporal resolution allowed to visualize the detailed dynamics of external flash-boiling for the first time. We identified different mechanisms of jet break-up. At chamber pressures lower than the vapor pressure the laminar jet evolves to a meandering stream. In this stage, bubbles start to nucleate and violently expand upstream the nozzle. At lower vacuum pressures the initially cylindrical jet elongates, forming a liquid sheet that breaks in branches and later in drops. At very low pressures both mechanisms are responsible for the jet breaking. We calculated the size distribution of the ejected droplets, their individual trajectories, velocities as well as the spray angle as a function of the dimensionless vacuum pressure.

Superconducting Vacuum-Gap Crossovers for High Performance Microwave Applications

NASA Technical Reports Server (NTRS)

Denis, Kevin L.; Brown, Ari D.; Chang, Meng-Ping; Hu, Ron; U-Yen, Kongpop; Wollack, Edward J.

2016-01-01

The design and fabrication of low-loss wide-bandwidth superconducting vacuum-gap crossovers for high performance millimeter wave applications are described. In order to reduce ohmic and parasitic losses at millimeter wavelengths a vacuum gap is preferred relative to dielectric spacer. Here, vacuum-gap crossovers were realized by using a sacrificial polymer layer followed by niobium sputter deposition optimized for coating coverage over an underlying niobium signal layer. Both coplanar waveguide and microstrip crossover topologies have been explored in detail. The resulting fabrication process is compatible with a bulk micro-machining process for realizing waveguide coupled detectors, which includes sacrificial wax bonding, and wafer backside deep reactive ion etching for creation of leg isolated silicon membrane structures. Release of the vacuum gap structures along with the wax bonded wafer after DRIE is implemented in the same process step used to complete the detector fabrication. ?

Cryogenic Thermal Performance Testing of Bulk-Fill and Aerogel Insulation Materials

NASA Technical Reports Server (NTRS)

Scholtens, B. E.; Fesmire, J. E.; Sass, J. P.; Augustynowicz, S. D.; Heckle, K. W.

2007-01-01

The research testing and demonstration of new bulk-fill materials for cryogenic thermal insulation systems was performed by the Cryogenics Test Laboratory at NASA Kennedy Space Center. Thermal conductivity testing under actual-use cryogenic conditions is a key to understanding the total system performance encompassing engineering, economics, and materials factors. A number of bulk fill insulation materials, including aerogel beads, glass bubbles, and perlite powder, were tested using a new cylindrical cryostat. Boundary temperatures for the liquid nitrogen boil-off method were 293 K and 78 K. Tests were performed as a function of cold vacuum pressure from high vacuum to no vacuum conditions. Results are compared with other complementary test methods in the range of 300 K to 20 K. Various testing techniques are shown to be required to obtain a complete understanding of the operating performance of a material and to provide data for answers to design engineering questions.

Vacuum injection of hydrogen micro-sphere beams

NASA Astrophysics Data System (ADS)

Trostell, Bertil

1995-02-01

The design, construction and operation of a facility producing hydrogen micro-sphere beams in vacuum are summarized. A scheme is utilized, where a liquid hydrogen jet is broken up into droplets, which are injected into vacuum through a capillary at continuum gas flow conditions. In a typical beam, 40 μm diameter micro-spheres, generated at a frequency of 70 kHz, travel at free flight speeds of 60 m/s. The angular divergence of the beam amounts to ±0.04°. The intention is to use the micro-sphere beams as high luminosity internal targets in the WASA experimental station at the CELSIUS cooler storage ring in Uppsala. A time averaged target density profile, having a FWHM and peak density of 3.5 mm and 5 × 10 16 atoms/cm 2, respectively, is obtained 2.5 m downstream of the capillary exit.

VACUUM SEALING MEANS FOR LOW VACUUM PRESSURES

DOEpatents

Milleron, N.

1962-06-12

S>A vacuum seal is designed in which the surface tension of a thin layer of liquid metal of low vapor pressure cooperates with adjacent surfaces to preclude passages of gases across pressure differentials as low as 10/sup -8/ mm Hg. Mating contiguous surfaces composed of copper, brass, stainless steel, nickel, molybdenum, tungsten, tantalum, glass, quartz, and/or synthetic mica are disposed to provide a maximum tolerance, D, expressed by 2 gamma /P/sub 1/, where gamma is the coefflcient of the surface tension of the metal sealant selected in dynes/cm/sub 2/. Means for heating the surfaces remotely is provided where temperatures drop below about 250 deg C. A sealant consisting of an alloy of gallium, indium, and tin, among other combinations tabulated, is disposed therebetween after treating the surfaces to improve wettability, as by ultrasonic vibrations, the surfaces and sealants being selected according to the anticipated experimental conditions of use. (AEC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffman, A. S.; Debefve, L. M.; Gates, B. C., E-mail: bcgates@ucdavis.edu

X-ray absorption spectroscopy is an element-specific technique for probing the local atomic-scale environment around an absorber atom. It is widely used to investigate the structures of liquids and solids, being especially valuable for characterization of solid-supported catalysts. Reported cell designs are limited in capabilities—to fluorescence or transmission and to static or flowing atmospheres, or to vacuum. Our goal was to design a robust and widely applicable cell for catalyst characterizations under all these conditions—to allow tracking of changes during genesis and during operation, both under vacuum and in reactive atmospheres. Herein, we report the design of such a cell andmore » a demonstration of its operation both with a sample under dynamic vacuum and in the presence of gases flowing at temperatures up to 300 °C, showing data obtained with both fluorescence and transmission detection. The cell allows more flexibility in catalyst characterization than any reported.« less

Vacuum pumps and systems: A review of current practice

NASA Technical Reports Server (NTRS)

Giles, Stuart

1986-01-01

A review of the fundamental characteristics of the many types of vacuum pumps and vacuum pumping systems is given. The optimum pumping range, relative cost, performance limitations, maintenance problems, system operating costs and similar subjects are discussed. Experiences from the thin film deposition, chemical processing, material handling, food processing and other industries, as well as space simulation are used to support conclusions and recommendations.

Development of a modified dry curing process for beef.

PubMed

Hayes, J E; Kenny, T A; Ward, P; Kerry, J P

2007-11-01

The development of a dry curing process using physical treatments to promote the diffusion of the cure ingredients was studied. Vacuum pulsing with and without tumbling, continuous vacuum, and tumbling only treatments were compared with a conventional static dry cure control method on beef M. supraspinatus. Vacuum tumble and tumble only treatments gave highest core salt content after 7 days conditioning (3.3% and 3.1%, respectively). All test treatments resulted in higher colour uniformity and lower % cook loss in comparison to control (P<0.001). The control and vacuum pulsed samples were tougher (P<0.001). Vacuum tumble and tumble only treatments gave higher acceptability (P<0.001). Based on these findings for M. supraspinatus, indicating that the vacuum tumble treatments gave the best results, further testing of this method was conducted using the M. biceps femoris in addition to the M. supraspinatus. Cured beef slices were stored in modified atmosphere packs (MAP) (80%N(2):20%CO(2)) for up to 28 day at 4°C. Redness (a(∗), P<0.001) decreased over storage time in M. biceps femoris. Vacuum tumble treatment increased (P<0.05) redness in M. supraspinatus. Results obtained demonstrate the benefits of vacuum tumbling over the other physical treatments as a method for accelerating the dry curing process, producing dry cured beef products with enhanced organoleptic quality and increased yields.

Vacuum Brazing of Accelerator Components

NASA Astrophysics Data System (ADS)

Singh, Rajvir; Pant, K. K.; Lal, Shankar; Yadav, D. P.; Garg, S. R.; Raghuvanshi, V. K.; Mundra, G.

2012-11-01

Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

Double Vacuum Bag Process for Resin Matrix Composite Manufacturing

NASA Technical Reports Server (NTRS)

Hou, Tan-Hung (Inventor); Jensen, Brian J. (Inventor)

2007-01-01

A double vacuum bag molding assembly with improved void management and laminate net shape control which provides a double vacuum enviromnent for use in fabricating composites from prepregs containing air and/or volatiles such as reactive resin matrix composites or composites from solvent containing prepregs with non-reactive resins matrices. By using two vacuum environments during the curing process, a vacuum can be drawn during a B-stage of a two-step cycle without placing the composite under significant relative pressure. During the final cure stage, a significant pressure can be applied by releasing the vacuum in one of the two environments. Inner and outer bags are useful for creating the two vacuum environments with a perforated tool intermediate the two. The composite is placed intermediate a tool plate and a caul plate in the first environment with the inner bag and tool plate defining the first environment. The second environment is characterized by the outer bag which is placed over the inner bag and the tool plate.

Design of two blackbody sources for millimeter and sub-millimeter wave Fourier transform spectrometry

NASA Astrophysics Data System (ADS)

Colin, Angel

2014-03-01

This paper describes an experimental setup for the spectral calibration of bolometric detectors used in radioastronomy. The system is composed of a Martin-Puplett interferometer with two identical artificial blackbody sources operating in the vacuum mode at 77 K and 300 K simultaneously. One source is integrated into a liquid nitrogen cryostat, and the other one into a vacuum chamber at room temperature. The sources were designed with a combination of conical with cylindrical geometries thus forming an orthogonal configuration to match the internal optics of the interfermometer. With a simple mathematical model we estimated emissivities of ε 0.995 for each source.

Evaluation of tantalum 316 stainless steel transition joints

NASA Technical Reports Server (NTRS)

Stoner, D. R.

1972-01-01

Tubular transition joints providing a metallurgically bonded connection between tantalum and 316 stainless steel pipe sections were comparatively evaluated for durability under thermal cycling conditions approximating the operation of a SNAP-8 mercury boiler. Both coextruded and vacuum brazed transition joints of 50mm (2 inch) diameter were tested by thermal cycling 100 times between 730 C and 120 C(1350 F and 250 F) in a high vacuum environment. The twelve evaluated transition joints survived the full test sequence without developing leaks, although liquid penetrant bond line indications eventually developed in all specimens. The brazed transition joints exhibited the best dimensional stability and bond line durability.

Recent progress of carbon nanotube field emitters and their application.

PubMed

Seelaboyina, Raghunandan; Choi, Wonbong

2007-01-01

The potential of utilizing carbon nanotube field emission properties is an attractive feature for future vacuum electronic devices including: high power microwave, miniature x-ray, backlight for liquid crystal displays and flat panel displays. Their high emission current, nano scale geometry, chemical inertness and low threshold voltage for emission are attractive features for the field emission applications. In this paper we review the recent developments of carbon nanotube field emitters and their device applications. We also discuss the latest results on field emission current amplification achieved with an electron multiplier microchannel plate, and emission performance of multistage field emitter based on oxide nanowire operated in poor vacuum.

Aerogel Beads as Cryogenic Thermal Insulation System

NASA Technical Reports Server (NTRS)

Fesmire, J. E.; Augustynowicz, S. D.; Rouanet, S.; Thompson, Karen (Technical Monitor)

2001-01-01

An investigation of the use of aerogel beads as thermal insulation for cryogenic applications was conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Steady-state liquid nitrogen boiloff methods were used to characterize the thermal performance of aerogel beads in comparison with conventional insulation products such as perlite powder and multilayer insulation (MLI). Aerogel beads produced by Cabot Corporation have a bulk density below 100 kilograms per cubic meter (kg/cubic m) and a mean particle diameter of 1 millimeter (mm). The apparent thermal conductivity values of the bulk material have been determined under steady-state conditions at boundary temperatures of approximately 293 and 77 kelvin (K) and at various cold vacuum pressures (CVP). Vacuum levels ranged from 10(exp -5) torr to 760 torr. All test articles were made in a cylindrical configuration with a typical insulation thickness of 25 mm. Temperature profiles through the thickness of the test specimens were also measured. The results showed the performance of the aerogel beads was significantly better than the conventional materials in both soft-vacuum (1 to 10 torr) and no-vacuum (760 torr) ranges. Opacified aerogel beads performed better than perlite powder under high-vacuum conditions. Further studies for material optimization and system application are in progress.

Heat Flow Measurement and Analysis of Thermal Vacuum Insulation

NASA Astrophysics Data System (ADS)

Laa, C.; Hirschl, C.; Stipsitz, J.

2008-03-01

A new kind of calorimeter has been developed at Austrian Aerospace to measure specific material parameters needed for the analysis of thermal vacuum insulation. A detailed description of the measuring device and the measurement results will be given in this paper. This calorimeter facility allows to measure the heat flow through the insulation under vacuum conditions in a wide temperature range from liquid nitrogen to ambient. Both boundary temperatures can be chosen within this range. Furthermore the insulation can be characterized at high vacuum or under degraded vacuum, the latter is simulated by using helium or nitrogen gas. The mechanisms of heat transfer have been investigated, namely infrared radiation between the reflective layers of the insulation and conduction through the interleaving spacer material. A mathematical description of the heat flow through the insulation has been derived. Based on this, the heat flow for a typical insulation material has been calculated by finite element analysis by use of the sotware tool Ansys®. Such a transient calculation is needed to determine the time to reach thermal equilibrium, which is mandatory for a proper interpretation and evaluation of the measurement. The new insulation measurement results combined with the proposed type of analysis can be applied to better understand the thermal behavior of any kind of cryogenic system.

Evaluation of Double-Vacuum-Bag Process For Composite Fabrication

NASA Technical Reports Server (NTRS)

Hou, T. H.; Jensen, B. J.

2004-01-01

A non-autoclave vacuum bag process using atmospheric pressure alone that eliminates the need for external pressure normally supplied by an autoclave or a press is an attractive method for composite fabrication. This type of process does not require large capital expenditures for tooling and processing equipment. In the molding cycle (temperature/pressure profile) for a given composite system, the vacuum application point has to be carefully selected to achieve the final consolidated laminate net shape and resin content without excessive resin squeeze-out. The traditional single-vacuum- bag (SVB) process is best suited for molding epoxy matrix based composites because of their superior flow and the absence of reaction by-products or other volatiles. Other classes of materials, such as polyimides and phenolics, generate water during cure. In addition, these materials are commonly synthesized as oligomers using solvents to facilitate processability. Volatiles (solvents and reaction byproducts) management therefore becomes a critical issue. SVB molding, without additional pressure, normally fails to yield void-free quality composites for these classes of resin systems. A double-vacuum- bag (DVB) process for volatile management was envisioned, designed and built at the NASA Langley Research Center. This experimental DVB process affords superior volatiles management compared to the traditional SVB process. Void-free composites are consistently fabricated as measured by C-scan and optical photomicroscopy for high performance polyimide and phenolic resins.

Apparatus and method for gelling liquefied gasses

NASA Technical Reports Server (NTRS)

Elliott, Adam (Inventor); DiSalvo, Roberto (Inventor); Shepherd, Phillip (Inventor); Kosier, Ryan (Inventor)

2011-01-01

A method and apparatus for gelling liquid propane and other liquefied gasses includes a temperature controlled churn mixer, vacuum pump, liquefied gas transfer tank, and means for measuring amount of material entering the mixer. The apparatus and method are particularly useful for the production of high quality rocket fuels and propellants.

Environmental Chemistry Compound Identification Using High Resolution Mass Spectrometry Data Integrated to the EPA Chemistry Dashboard (EAS)

EPA Science Inventory

There is a growing need for rapid chemical screening and prioritization to inform regulatory decision-making on thousands of chemicals in the environment. We have previously used high-resolution mass spectrometry to examine household vacuum dust samples using liquid chromatograph...

Distillation device supplies cesium vapor at constant pressure

NASA Technical Reports Server (NTRS)

Basiulis, A.; Shefsiek, P. K.

1968-01-01

Distillation apparatus in the form of a U tube supplies small amounts of pure cesium vapor at constant pressure to a thermionic converter. The upstream leg of the U tube is connected to a vacuum pump to withdraw noncondensable impurities, the bottom portion serves as a reservoir for the liquid cesium.

USE OF A VACUUM FILTRATION TECHNIQUE TO STUDY LEACHING OF INDIGENOUS VIRUSES FROM RAW WASTEWATER SLUDGE

EPA Science Inventory

The relative efficiencies of a buffered beef extract solution, sewage secondary effluent, and distilled water, were compared in a study designed to simulate leaching of indigenous enteric viruses from raw primary sewage sludge. The initial sludge liquid fractions, termed sludge l...

Production of Magnesium by Vacuum Aluminothermic Reduction with Magnesium Aluminate Spinel as a By-Product

NASA Astrophysics Data System (ADS)

Wang, Yaowu; You, Jing; Peng, Jianping; Di, Yuezhong

2016-06-01

The Pidgeon process currently accounts for 85% of the world's magnesium production. Although the Pidgeon process has been greatly improved over the past 10 years, such production still consumes much energy and material and creates much pollution. The present study investigates the process of producing magnesium by employing vacuum aluminothermic reduction and by using magnesite as material and obtaining magnesium aluminate spinel as a by-product. The results show that compared with the Pidgeon process, producing magnesium by vacuum aluminothermic reduction can save materials by as much as 50%, increase productivity up to 100%, and save energy by more than 50%. It can also reduce CO2 emission by up to 60% and realize zero discharge of waste residue. Vacuum aluminothermic reduction is a highly efficient, low-energy-consumption, and environmentally friendly method of producing magnesium.

Modeling and experimental investigation of x-ray spectra from a liquid metal anode x-ray tube

NASA Astrophysics Data System (ADS)

David, Bernd R.; Thran, Axel; Eckart, Rainer

2004-11-01

This paper presents simulated and measured spectra of a novel type of x-ray tube. The bremsstrahlung generating principle of this tube is based on the interaction of high energetic electrons with a turbulently flowing liquid metal separated from the vacuum by a thin window. We simulated the interaction of 50-150 keV electrons with liquid metal targets composed of the elements Ga, In, Sn, as well as the solid elements C, W and Re used for the electron windows. We obtained x-ray spectra and energy loss curves for various liquid metal/window combinations and thicknesses of the window material. In terms of optimum heat transport a thin diamond window in combination with the liquid metal GaInSn is the best suited system. If photon flux is the optimization criteria, thin tungsten/rhenium windows cooled by GaInSn should be preferred.

Linus cycle calculations including plasma transport and resistive flux loss in an incompressible liner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quimby, D.C.; Hoffman, A.L.; Vlases, G.C.

1980-08-01

In the LINUS fusion reactor concept, a rotating liquid metal liner is used for reversible mechanical compression of thermonuclear plasmas, where a vacuum field buffer zone is used between the plasma and wall to reduce transport losses. A one-dimensional plasma transport and burn code, including incompressible liner dynamics with heat transfer and temperature dependent flux diffusion in the liquid metal, is used to model LINUS cycles. The effects of compressibility are treated as a perturbation. Numerical coefficients are derived for simple LINUS scaling laws. The particular case of plasma contact with the liquid metal is studied to determine the effectmore » on LINUS performance.« less

Femtosecond X-ray diffraction from an aerosolized beam of protein nanocrystals

DOE PAGES

Awel, Salah; Kirian, Richard A.; Wiedorn, Max O.; ...

2018-02-01

High-resolution Bragg diffraction from aerosolized single granulovirus nanocrystals using an X-ray free-electron laser is demonstrated. The outer dimensions of the in-vacuum aerosol injector components are identical to conventional liquid-microjet nozzles used in serial diffraction experiments, which allows the injector to be utilized with standard mountings. As compared with liquid-jet injection, the X-ray scattering background is reduced by several orders of magnitude by the use of helium carrier gas rather than liquid. Such reduction is required for diffraction measurements of small macromolecular nanocrystals and single particles. High particle speeds are achieved, making the approach suitable for use at upcoming high-repetition-rate facilities.

Containerless processing of undercooled melts

NASA Technical Reports Server (NTRS)

Shong, D. S.; Graves, J. A.; Ujiie, Y.; Perepezko, J. H.

1987-01-01

Containerless drop tube processing allows for significant levels of liquid undercooling through control of parameters such as sample size, surface coating and cooling rate. A laboratory scale (3 m) drop tube has been developed which allows the undercooling and solidification behavior of powder samples to be evaluated under low gravity free-fall conditions. The level of undercooling obtained in an InSb-Sb eutectic alloy has been evaluated by comparing the eutectic spacing in drop tube samples with a spacing/undercooling relationship established using thermal analysis techniques. Undercoolings of 0.17 and 0.23 T(e) were produced by processing under vacuum and He gas conditions respectively. Alternatively, the formation of an amorphous phase in a Ni-Nb eutectic alloy indicates that undercooling levels of approximately 500 C were obtained by drop tube processing. The influence of droplet size and gas environment on undercooling behavior in the Ni-Nb eutectic was evaluated through their effect on the amorphous/crystalline phase ratio. To supplement the structural analysis, heat flow modeling has been developed to describe the undercooling history during drop tube processing, and the model has been tested experimentally.

Dynamic underground stripping: steam and electric heating for in situ decontamination of soils and groundwater

DOEpatents

Daily, W.D.; Ramirez, A.L.; Newmark, R.L.; Udell, K.; Buetnner, H.M.; Aines, R.D.

1995-09-12

A dynamic underground stripping process removes localized underground volatile organic compounds from heterogeneous soils and rock in a relatively short time. This method uses steam injection and electrical resistance heating to heat the contaminated underground area to increase the vapor pressure of the contaminants, thus speeding the process of contaminant removal and making the removal more complete. The injected steam passes through the more permeable sediments, distilling the organic contaminants, which are pumped to the surface. Large electrical currents are also applied to the contaminated area, which heat the impermeable subsurface layers that the steam has not penetrated. The condensed and vaporized contaminants are withdrawn by liquid pumping and vacuum extraction. The steam injection and electrical heating steps are repeated as necessary. Geophysical imaging methods can be used to map the boundary between the hot, dry, contamination-free underground zone and the cool, damp surrounding areas to help monitor the dynamic stripping process. 4 figs.

Dynamic underground stripping: steam and electric heating for in situ decontamination of soils and groundwater

DOEpatents

Daily, William D.; Ramirez, Abelardo L.; Newmark, Robin L.; Udell, Kent; Buetnner, Harley M.; Aines, Roger D.

1995-01-01

A dynamic underground stripping process removes localized underground volatile organic compounds from heterogeneous soils and rock in a relatively short time. This method uses steam injection and electrical resistance heating to heat the contaminated underground area to increase the vapor pressure of the contaminants, thus speeding the process of contaminant removal and making the removal more complete. The injected steam passes through the more permeable sediments, distilling the organic contaminants, which are pumped to the surface. Large electrical currents are also applied to the contaminated area, which heat the impermeable subsurface layers that the steam has not penetrated. The condensed and vaporized contaminants are withdrawn by liquid pumping and vacuum extraction. The steam injection and electrical heating steps are repeated as necessary. Geophysical imaging methods can be used to map the boundary between the hot, dry, contamination-free underground zone and the cool, damp surrounding areas to help monitor the dynamic stripping process.

An efficient cooling loop for connecting cryocooler to a helium reservoir

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, C.E.; Abbott, C.S.R.; Leitner, D.

2003-09-21

The magnet system of the VENUS ECR Ion Source at LBNL has two 1.5-watt cryocoolers suspended in the cryostat vacuum. Helium vapor from the liquid reservoir is admitted to a finned condenser bolted to the cryocooler 2nd stage and returns as liquid via gravity. Small-diameter flexible tubes allow the cryocoolers to be located remotely from the reservoir. With 3.1 watts load, the helium reservoir is maintained at 4.35 K, 0.05K above the cryocooler temperature. Design, analysis, and performance are presented.

Thin Aerogel as a Spacer in Multilayer Insulation

NASA Technical Reports Server (NTRS)

Moroz, Nancy

2015-01-01

Cryogenic fluid management is a critical technical area that is needed for future space exploration. A key challenge is the storability of liquid hydrogen (LH2), liquid methane (LCH4), and liquid oxygen (LOX) propellants for long-duration missions. The storage tanks must be well-insulated to prevent over-pressurization and venting, which can lead to unacceptable propellant losses for long-duration missions to Mars and beyond. Aspen Aerogels had validated the key process step to enable the fabrication of thin, low-density aerogel materials. The multilayer aerogel insulation (MLAI) system prototypes were prepared using sheets of aerogel materials with superior thermal performance exceeding current state-of-the-art insulation for space applications. The exceptional properties of this system include a new breakthrough in high-vacuum cryogenic thermal insulation, providing a durable material with excellent thermal performance at a reduced cost when compared to longstanding state-of-the-art multilayer insulation systems. During the Phase II project, further refinement and qualification/system-level testing of the MLAI system will be performed for use in cryogenic storage applications. Aspen has been in discussions with United Launch Alliance, LLC; NASA's Kennedy Space Center; and Yetispace, Inc., to test the MLAI system on real-world tanks such as Vibro-Acoustic Test Article (VATA) or the Cryogenic Orbital Testbed (CRYOTE).

Thin Aerogel as a Spacer in Multilayer Insulation

NASA Technical Reports Server (NTRS)

Moroz, Nancy

2015-01-01

Cryogenic fluid management is a critical technical area that is needed for future space exploration. A key challenge is the storability of liquid hydrogen (LH2), liquid methane (LCH4), and liquid oxygen (LOX) propellants for long-duration missions. The storage tanks must be well-insulated to prevent over-pressurization and venting, which can lead to unacceptable propellant losses for long-duration missions to Mars and beyond. Aspen Aerogels had validated the key process step to enable the fabrication of thin, low-density aerogel materials. The multilayer aerogel insulation (MLAI) system prototypes were prepared using sheets of aerogel materials with superior thermal performance exceeding current state-of-the-art insulation for space applications. The exceptional properties of this system include a new breakthrough in high-vacuum cryogenic thermal insulation, providing a durable material with excellent thermal performance at a reduced cost when compared to longstanding state-of-the-art multilayer insulation systems. During the Phase II project, further refinement and qualification/system-level testing of the MLAI system will be performed for use in cryogenic storage applications. Aspen has been in discussions with United Launch Alliance, LLC; NASA's Kennedy Space Center; and Yetispace, Inc., to test the MLAI system on rea-lworld tanks such as Vibro-Acoustic Test Article (VATA) or the Cryogenic Orbital Testbed (CRYOTE).