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A Partial Equilibrium Theory for Drops and Capillary Liquids

Description: The two-century old theory of Young and Laplace retains apowerful influence on surface and interface studies because itquantitatively predicts the height of rise of capillary liquids from thecontact angles of drops. But the classical theory does not acknowledgethat equilibrium requires separate minimization of partial free energiesof one-component liquids bonded to immiscible solids. We generalize atheorem of Gibbs and Curie to obtain a partial equilibrium (PE) theorythat does so and that also predicts the height of capillary rise fromcontact angles of drops. Published observations and our own measurementsof contact angles of water bonded to glass and Teflon surfaces supportthe conclusion of PE theory that contact angles of meniscuses and ofdrops are different dependent variables. PE theory provides thermodynamicand kinetic guidance to nanoscale processes that the classical theoryobscures, as illustrated by examples in our concludingsection.
Date: October 26, 2006
Creator: Searcy, Alan W.; Beruto, Dario T. & Barberis, Fabrizio
Partner: UNT Libraries Government Documents Department


Description: Dynamic loading experiments were performed on inert Teflon (Polytetrafluoroethylene) samples, initially heated to the temperature of 200 C, to test its behavior under these conditions for its use in other heated experiments. Tests were performed in the 100 mm diameter bore propellant driven gas gun with piezo-resistive manganin pressure gauges imbedded into the samples to measure loading pressures. Experimental data provided new information on the shock velocity - particle velocity relationship for the heated material and showed no adverse effect of temperature on the insulating properties of the material.
Date: June 13, 2007
Creator: Urtiew, P A; Forbes, J W; Tarver, C M; Vandersall, K S & Garcia, F
Partner: UNT Libraries Government Documents Department

Size-Resolved Particle Number and Volume Emission Factors for On-Road Gasoline and Diesel Motor Vehicles

Description: Average particle number concentrations and size distributions from {approx}61,000 light-duty (LD) vehicles and {approx}2500 medium-duty (MD) and heavy-duty (HD) trucks were measured during the summer of 2006 in a San Francisco Bay area traffic tunnel. One of the traffic bores contained only LD vehicles, and the other contained mixed traffic, allowing pollutants to be apportioned between LD vehicles and diesel trucks. Particle number emission factors (particle diameter D{sub p} > 3 nm) were found to be (3.9 {+-} 1.4) x 10{sup 14} and (3.3 {+-} 1.3) x 10{sup 15} kg{sup -1} fuel burned for LD vehicles and diesel trucks, respectively. Size distribution measurements showed that diesel trucks emitted at least an order of magnitude more particles for all measured sizes (10 < D{sub p} < 290 nm) per unit mass of fuel burned. The relative importance of LD vehicles as a source of particles increased as D{sub p} decreased. Comparing the results from this study to previous measurements at the same site showed that particle number emission factors have decreased for both LD vehicles and diesel trucks since 1997. Integrating size distributions with a volume weighting showed that diesel trucks emitted 28 {+-} 11 times more particles by volume than LD vehicles, consistent with the diesel/gasoline emission factor ratio for PM{sub 2.5} mass measured using gravimetric analysis of Teflon filters, reported in a companion paper.
Date: April 10, 2009
Creator: Ban-Weiss, George A.; Lunden, Melissa M.; Kirchstetter, Thomas W. & Harley, Robert A.
Partner: UNT Libraries Government Documents Department

Mass spectrometer vacuum-lock carriages coated with Teflon-S

Description: Seizing of the metal-to-metal, piston-like carriages of a thermal ionization mass spectrometer vacuum lock was eliminated by replacing 0.0015 in. of the carriage surface with Teflon-S. The vacuum lock has been operated 1600 times in the 3.5 years since the carriages were coated. Both the plastic surface and the mass spectrometer vacuum remain satisfactory. (auth)
Date: November 26, 1973
Creator: Howard, O.H. & Langdon, A.
Partner: UNT Libraries Government Documents Department

Development of an Electrostatic Dust Detector for use in a Tokamak Reactor

Description: Initial results from a novel device to detect dust particles settling on remote surfaces are presented. Dust particle inventories are a concern in next-step fusion devices. The increase in duty cycle will lead to a scale-up in the amount of particles generated by plasma material interactions. These particles will be chemically and radiologically hazardous and it will be important to establish that the in-vessel particle inventory is within regulatory limits. The detection device consists of two interlocking combs of closely spaced conductive traces on a Teflon circuit board. When a DC bias is applied impinging dust creates a transient short circuit between the traces. The increase in bias current generates a signal pulse that is counted by standard nuclear counting electronics. We present data on the response of the device in air and vacuum to carbon particles.
Date: September 10, 2003
Creator: Bader, A.; C.H. Skinner, A.L. Roquemore & Langish, S.
Partner: UNT Libraries Government Documents Department

Air agglomeration of hydrophobic particles

Description: The agglomeration of hydrophobic particles in an aqueous suspension was accomplished by introducing small amounts of air into the suspension while it was agitated vigorously. The extent of aggregation was proportional both to the air to solids ratio and to the hydrophobicity of the solids. For a given air/solids ratio, the extent of aggregation of different materials increased in the following order: graphite, gilsonite, coal coated with heptane, and Teflon. The structure of agglomerates produced from coarse Teflon particles differed noticeably from the structure of bubble-particle aggregates produced from smaller, less hydrophobic particles.
Date: December 31, 1995
Creator: Drzymala, J. & Wheelock, T.D.
Partner: UNT Libraries Government Documents Department

MIL-L-87177 and CLT:X-10 Lubricants Improve Electrical Connector Fretting Corrosion Behavior

Description: We have conducted a fretting research project using MIL-L-87177 and CLT: X-10 lubricants on Nano-miniature connectors. When they were fretted without lubricant, individual connectors first exceeded our 0.5 ohm failure criteria from 2,341 to 45,238 fretting cycles. With additional fretting, their contact resistance increased to more than 100,000 ohms. Unmodified MIL-L-87177 lubricant delayed the onset of first failure to between 430,000 and over 20,000,000 fretting cycles. MIL-L-87177 modified by addition of Teflon powder delayed first failure to beyond 5 million fretting cycles. Best results were obtained when Teflon was used and also when both the straight and modified lubricants were poured into and then out of the connector. CLT: X-10 lubricant delayed the onset of first failure to beyond 55 million cycles in one test where a failure was actually observed and to beyond 20 million cycles in another that was terminated without failure. CLT: X-10 recovered an unlubricated connector driven deeply into failure, with six failed pins recovering immediately and four more recovering during an additional 420 thousand fretting cycles. MIL-L-87177 was not able to recover a connector under similar conditions.
Date: October 12, 1999
Partner: UNT Libraries Government Documents Department

The corrosion effect of ozonated seawater solution on titanium in polymer generated crevice environments

Description: Two different tests were designed to evaluate the reaction of various polymers and grade-2 titanium in ozonated seawater in conjunction with a comparative analysis in an aerated seawater solution. The first was a weight loss test measuring the weight change of Polyvinyl chloride (PVC), Polyethylene and Teflon{trademark} in both ozonated and aerated artificial seawater baths. The second test was designed to induce crevice corrosion on the titanium test samples using various crevice generating materials in both ozonated and aerated solutions. The materials used to create the crevices were grade-2 titanium washers, PVC, Polyethylene, Saran and Teflon{trademark}. The weight loss test showed that all three polymers lost weight in the ozonated bath. The results of the titanium washer crevice test provided no indication of corrosion or surface discoloration in either the ozonated or aerated solutions. Energy dispersive spectrometry (EDS) analysis found no fluorine, chlorine or other corrosion product. The PVC samples in the aerated bath also showed no signs of corrosion, but the PVC samples in the ozonated tank had light brown rings of surface discoloration. One of the ozonated PVC samples did show evidence of chlorine in the corrosion product. The outer circumference of the ozonated PVC washers exhibited the same type bleaching effect as in the weight loss samples, but the whitening of these samples were more pronounced. The polyethylene samples under aeration showed no discoloration or presence of fluorine or chlorine. The polyethylene crevice samples in the ozonated solution all exhibited the distinct brilliant blue color of titanium oxide. Fluorine was found in the corrosion product on only one of the samples. Chlorine was found on the surface of one of the other corrosion coupons. The results of the Teflon{trademark} crevice samples substantiated the previous Rensselaer study.
Date: January 1, 1998
Creator: Leveillee, S.Y.
Partner: UNT Libraries Government Documents Department

Thin teflon-like films for eliminating adhesion in released polysilicon microstructures

Description: This paper presents a method for depositing thin Teflon-like films using a commercial plasma reactor to eliminate adhesion or stiction in released polysilicon microstructures. A Lam 384T oxide etch system is used in a remote plasma mode with commercially available trifluoromethane (CHF{sub 3}) to deposit thin hydrophobic films around and under released microstructures. Hard, uniform, Teflon-like films which penetrate into undercuts beneath structures have been produced. Thus far, surfaces beneath gears as large as 1600 micron diameter with a gap of 2.0 microns are hydrophobic after being exposed to plasma treatment. These Teflon-like coatings have been shown to reduce the coefficient of friction from 1.0 to 0.07.
Date: December 31, 1996
Creator: Smith, B.K.; Sniegowski, J.J. & LaVigne, G.
Partner: UNT Libraries Government Documents Department

Development of Equipment to Separate Nonthermal and Thermal Effects of Radio Frequency Energy on Microorganisms

Description: A radio frequency (RF) dielectric heater has been developed for isolating thermal and nonthermal effects of RF energy on microorganisms in liquid foods. The modified heater enables the simultaneous application of RF energy and removal of thermal energy from the liquids. A double-pipe heat exchanger is an integral part of the heater. The outer pipe is made of Teflon. The inner pipe is made of stainless steel that is grounded in the RF circuit. Liquid food flows through the annular region between the two concentric pipes. Cooling water flows through the stainless steel pipe. The food in the annular region absorbs the RF energy. Concurrently, the cooling water flowing in the inner pipe removes the thermal energy from the food, thus controlling the temperature.
Date: November 1, 1999
Creator: Geveke, D.J.; Kozempel, M. & Brunkhorst, C.
Partner: UNT Libraries Government Documents Department

Metallization and Modification of Low-k Dielectric Materials

Description: Aluminum was deposited onto both Teflon AF and Parylene AF surfaces by chemical vapor deposition of trimethylaluminum. This work shows that similar thin film (100 Angstroms) aluminum oxide adlayers form on both polymers at the low temperature dosing conditions used in the studies. Upon anneal to room temperature and above, defluorination of the polymer surfaces increased and resulted in fluorinated aluminum oxide adlayers; the adlayers were thermally stable to the highest temperatures tested (600 K). Angle-resolved spectra showed higher levels of fluorination toward the polymer/adlayer interface region. Copper films were also deposited at low temperature onto Teflon AF using a copper hexafluoroacetylacetonate-cyclooctadiene precursor. Annealing up to 600 K resulted in the loss of precursor ligands and a shift to metallic copper. As with aluminum adlayers, some polymer defluorination and resulting metal (copper) fluoride was detected. Parylene AF and polystyrene films surfaces were modified by directly dosing with water vapor passed across a hot tungsten filament. Oxygen incorporation into polystyrene occurred exclusively at aromatic carbon sites, whereas oxygen incorporation into parylene occurred in both aromatic and aliphatic sites. Oxygen x-ray photoelectron spectra of the modified polymers were comparable, indicating that similar reactions occurred. The surface oxygenation of parylene allowed enhanced reactivity toward aluminum chemical vapor deposition. Silicon-carbon (Si-Cx) films were formed by electron beam bombardment of trimethylvinylsilane films which were adsorbed onto metal substrates at low temperatures in ultra-high vacuum. Oxygen was also added to the films by coadsorbing water before electron beam bombardment; the films were stable to more than 700 K, with increasing silicon-oxygen bond formation at elevated temperatures. Copper metal was sputter deposited in small increments onto non-oxygenated films. X-ray photoelectric spectra show three-dimensional copper growth (rather than layer-by-layer growth), indicating only weak interaction between the copper and underlying films. Annealing at elevated temperatures caused coalescence or growth ...
Date: December 2008
Creator: Martini, David M.
Partner: UNT Libraries

Pump Outs, General and D0 Considerations

Description: Seal Pump Outs (PO) are provided by specifically designing and providing redundant, or double, seals to create an annular volume that can be '(vacuum) pumped out' to test the integrity of both seals. The value of the technique is most readily apparent in the construction of large piping systems or vessels whose closure is on a different schedule than the nozzle closures, or whose nozzles are serially closed. In the case of D0, for instance, the high voltage boxes were put in place and leak checked before the vessel was closed and independent of the other nozzles. PO use is by no means limited to cryogenics and the supporting vacuum systems, but the discussion here will be limited to cryogenic applications. POs come in two generic service types; installation, and installation and monitor. The above high voltage box is an example of a static installation service application. Once the item is installed the PO can be, and almost universally is, capped, and revisited only on disassembly and reassembly. POs are constantly monitored after installation only when their seals, through cooldown gradient induced motion, vibration, cyclic load bolt seating, or other dynamic phenomena may degrade in performance over time. PO seals come in two general temperature service types; ambient and cryogenic temperatures. 'O' rings are the predominant warm seal. 'C', and other (Conoseal, Conflat, soft copper, etc.) metal seals (of copper, Inconel, indium, lead, stainless steel, alone or in combination) make up the usual field of cold seals. The much smaller class of cold seals made of metal spring activated Teflon or other spring activated seal materials have not been used here and will not be further addressed. In cryogenic work there are four regions that can be interfaced; cryogenic (cold), vacuum, atmosphere, and warm to cold transition nozzles (nozzle). Taken ...
Date: December 25, 1990
Creator: Mulholland, G.T.
Partner: UNT Libraries Government Documents Department

Electrodeposition of Uranium and Plutonium on Thin Carbon and Titanium Substrates

Description: Preparation of Pu and U targets on thin natural C (100 {micro}g/cm{sup 2}) and ti (2 and 3 {micro}m) substrates is described. The Actinide material of interest was first purified using ion exchange chromatography to remove any matrix contaminants or decay products present in the parent stock solution. The actinide solution was prepared in 0.05 M HNO{sub 3} with a final aliquot volume not exceeding 100 {micro}L for the deposition procedure. The electroplating cells were developed in-house and were primarily made of Teflon. The source material deposited ranged from 125 to 400 {micro}g/cm{sup 2}. It was determined that multiple layers of U and Pu were required to produce thicker targets on Ti. Plating efficiency was greatly affected by the cell volume, solution aliquot size, pre-treatment of the foils, solution mixing during palting, and the fit of the electrode contact with the target substrate. The final procedure used for deposition is described in detail.
Date: February 18, 2011
Creator: Henderson, R A; Gostic, J M; Burke, J T; Fisher, S E & Wu, C Y
Partner: UNT Libraries Government Documents Department

LLNL SMP Light Diffuser Fabrication and Preliminary Data

Description: We are developing a cylindrical light diffuser using shape memory polymer (SMP) whose diameter, length, stiffness, and diffusion profile can be tailored to suit a particular application. The cylindrical SMP diffuser is made by casting SMP around the end of a glass optical fiber using a teflon tube as the casting mold, and abrading the cured SMP surface to cause the light to leak radially outward. The inner diameter of the casting tube is slightly larger than the fiber diameter. A smaller teflon tube is positioned over the fiber (between the fiber and the casting tube) to approximately center the fiber tip in the casting tube. As the SMP cures, it bonds with the optical fiber, creating a strong joint without the need for additional adhesives or mechanical fixtures. A close-up of the SMP-fiber joint and the finished SMP diffuser are shown in Fig.1. The SMP formulation (developed in-house) was specifically designed to be optically transparent in the visible and near-infrared regions; the spectral absorption of the SMP is shown in Fig. 2. The low absorption is important because (1) it allows the light to travel the length of the diffuser without suffering excessive loss due to absorption and (2) it permits delivery of up to 7 W (300 {micro}m SMP rod on 100 {micro}m core multimode fiber) of laser power into the diffuser without damaging the diffuser. SMP is a good wave guiding material with a refractive index of approximately 1.5. Also, the SMP stiffness can be tailored from stiff (e.g. acrylic, Ea {approx} 10{sup 9} Pa) to very flexible (e.g. silicon rubber, Ea {approx} 10{sup 6} Pa). Finally, since SMP can self-actuate, the SMP diffuser could be designed to actuate into a shape other than a straight rod (e.g. 2D or 3D coil).
Date: June 2, 2006
Creator: Small IV, W
Partner: UNT Libraries Government Documents Department


Description: The High Flux Isotope Reactor at the Oak Ridge National Laboratory was upgraded to install a cold source in horizontal beam tube number 4. Calculations were performed and measurements were made to determine heating within the cold source and dose rates within and outside a shield tunnel surrounding the beam tube. This report briefly describes the calculations and presents comparisons of the measured and calculated results. Some calculated dose rates are in fair to good agreement with the measured results while others, particularly those at the shield interfaces, differ greatly from the measured results. Calculated neutron exposure to the Teflon seals in the hydrogen transfer line is about one fourth of the measured value, underpredicting the lifetime by a factor of four. The calculated cold source heating is in good agreement with the measured heating.
Date: March 1, 2009
Creator: Slater, Charles O; Primm, Trent; Pinkston, Daniel; Cook, David Howard; Selby, Douglas L; Ferguson, Phillip D et al.
Partner: UNT Libraries Government Documents Department

Rapid and sensitive gas chromatography ion-trap mass spectrometry method for the determination of tobacco specific N-nitrosamines in secondhand smoke

Description: Tobacco-specific nitrosamines (TSNAs) are some of the most potent carcinogens in tobacco and cigarette smoke. Accurate quantification of these chemicals is needed to help assess public health risks. We developed and validated a specific and sensitive method to measure four TSNAs in both the gas- and particle-phase of secondhand smoke (SHS) using gas chromatography and ion-trap tandem mass spectrometry,. A smoking machine in an 18-m3 room-sized chamber generated relevant concentrations of SHS that were actively sampled on Teflon coated fiber glass (TCFG) filters, and passively sampled on cellulose substrates. A simple solid-liquid extraction protocol using methanol as solvent was successfully applied to both filters with high recoveries ranging from 85 to 115percent. Tandem MS parameters were optimized to obtain the best sensitivity in terms of signal to-noise ratio (S/N) for the target compounds. For each TSNA, the major fragmentation pathways as well as ion structures were elucidated and compared with previously published data. The method showed excellent performances with a linear dynamic range between 2 and 1000 ng mL-1, low detection limits (S/N> 3) of 30-300 pg.ml-1 and precision with experimental errors below 10percent for all compounds. Moreover, no interfering peaks were observed indicating a high selectivity of MS/MS without the need for a sample clean up step. The sampling and analysis method provides a sensitive and accurate tool to detect and quantify traces of TSNA in SHS polluted indoor environments.
Date: July 1, 2009
Creator: SLEIMAN, Mohamad; MADDALENA, Randy L.; GUNDEL, Lara A. & DESTAILLATS, Hugo
Partner: UNT Libraries Government Documents Department

Compatibility of Fluorinert, FC-72, with selected materials.

Description: Removable encapsulants have been developed as replacement materials for electronic encapsulation. They can be removed from an electronic assembly in a fairly benign manner. Encapsulants must satisfy a limited number of criteria to be useful. These include processing ease, certain mechanical, thermal, and electrical properties, adhesion to common clean surfaces, good aging characteristics, and compatibility. This report discusses one aspect of the compatibility of removable blown epoxy foams with electronic components. Of interest is the compatibility of the blowing agent, Fluorinert{trademark} (FC-72) electronic fluid with electronic parts, components, and select materials. Excellent compatibility is found with most of the investigated materials. A few materials, such as Teflon{reg_sign} that are comprised of chemicals very similar to FC-72 show substantial absorption of FC-72. No compatibility issues have yet been identified even for the few materials that show substantial absorption.
Date: February 1, 2006
Creator: Aubert, James Henry & Sawyer, Patricia Sue
Partner: UNT Libraries Government Documents Department