WorldWideScience

Sample records for vapor lubricant equilibrium

  1. Fundamentals of Friction and Vapor Phase Lubrication

    National Research Council Canada - National Science Library

    Gellman, Andrew

    2004-01-01

    This is the final report for the three year research program on "Fundamentals of Friction and Vapor Phase Lubrication" conducted at Carnegie Mellon with support from AFOSR grant number F49630-01-1-0069...

  2. Evaporation rate and vapor pressure of selected polymeric lubricating oils.

    Science.gov (United States)

    Gardos, M. N.

    1973-01-01

    A recently developed ultrahigh-vacuum quartz spring mass sorption microbalance has been utilized to measure the evaporation rates of several low-volatility polymeric lubricating oils at various temperatures. The evaporation rates are used to calculate the vapor pressures by the Langmuir equation. A method is presented to accurately estimate extended temperature range evaporation rate and vapor pressure data for polymeric oils, incorporating appropriate corrections for the increases in molecular weight and the change in volatility of the progressively evaporating polymer fractions. The logarithms of the calculated data appear to follow linear relationships within the test temperature ranges, when plotted versus 1000/T. These functions and the observed effusion characteristics of the fluids on progressive volatilization are useful in estimating evaporation rate and vapor pressure changes on evaporative depletion.

  3. MEMS Lubrication by In-Situ Tribochemical Reactions From the Vapor Phase.

    Energy Technology Data Exchange (ETDEWEB)

    Dugger, Michael Thomas; Asay, David B.; Kim, Seong H.

    2008-01-01

    Vapor Phase Lubrication (VPL) of silicon surfaces with pentanol has been demonstrated. Two potential show stoppers with respect to application of this approach to real MEMS devices have been investigated. Water vapor was found to reduce the effectiveness of VPL with alcohol for a given alcohol concentration, but the basic reaction mechanism observed in water-free environments is still active, and devices operated much longer in mixed alcohol and water vapor environments than with chemisorbed monolayer lubricants alone. Complex MEMS gear trains were successfully lubricated with alcohol vapors, resulting in a factor of 104 improvement in operating life without failure. Complex devices could be made to fail if operated at much higher frequencies than previously used, and there is some evidence that the observed failure is due to accumulation of reaction products at deeply buried interfaces. However, if hypothetical reaction mechanisms involving heated surfaces are valid, then the failures observed at high frequency may not be relevant to operation at normal frequencies. Therefore, this work demonstrates that VPL is a viable approach for complex MEMS devices in conventional packages. Further study of the VPL reaction mechanisms are recommended so that the vapor composition may be optimized for low friction and for different substrate materials with potential application to conventionally fabricated, metal alloy parts in weapons systems. Reaction kinetics should be studied to define effective lubrication regimes as a function of the partial pressure of the vapor phase constituent, interfacial shear rate, substrate composition, and temperature.

  4. Isotope effects in the equilibrium and non-equilibrium vaporization of tritiated water and ice

    International Nuclear Information System (INIS)

    Baumgaertner, F.; Kim, M.-A.

    1990-01-01

    The vaporization isotope effect of the HTO/H 2 O system has been measured at various temperatures and pressures under equilibrium as well as non-equilibrium conditions. The isotope effect values measured in equilibrium sublimation or distillation are in good agreement with the theoretical values based on the harmonic oscillator model. In non-equilibrium vaporization at low temperatures ( 0 C), the isotope effect decreases rapidly with decreasing system pressure and becomes negligible when the system pressure is lowered more than one tenth of the equilibrium vapor pressure. At higher temperatures, the isotope effect decreases very slowly with decreasing system pressure. Discussion is extended for the application of the present results to the study of biological enrichment of tritium. (author)

  5. Student Understanding of Liquid-Vapor Phase Equilibrium

    Science.gov (United States)

    Boudreaux, Andrew; Campbell, Craig

    2012-01-01

    Student understanding of the equilibrium coexistence of a liquid and its vapor was the subject of an extended investigation. Written assessment questions were administered to undergraduates enrolled in introductory physics and chemistry courses. Responses have been analyzed to document conceptual and reasoning difficulties in sufficient detail to…

  6. Non-equilibrium phenomena near vapor-liquid interfaces

    CERN Document Server

    Kryukov, Alexei; Puzina, Yulia

    2013-01-01

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

  7. On the vapor-liquid equilibrium in hydroprocessing reactors

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-01

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

  8. Non-equilibrium responses of PFPE lubricants with various atomistic/molecular architecture at elevated temperature

    Science.gov (United States)

    Chung, Pil Seung; Song, Wonyup; Biegler, Lorenz T.; Jhon, Myung S.

    2017-05-01

    During the operation of hard disk drive (HDD), the perfluoropolyether (PFPE) lubricant experiences elastic or viscous shear/elongation deformations, which affect the performance and reliability of the HDD. Therefore, the viscoelastic responses of PFPE could provide a finger print analysis in designing optimal molecular architecture of lubricants to control the tribological phenomena. In this paper, we examine the rheological responses of PFPEs including storage (elastic) and loss (viscous) moduli (G' and G″) by monitoring the time-dependent-stress-strain relationship via non-equilibrium molecular dynamics simulations. We analyzed the rheological responses by using Cox-Merz rule, and investigated the molecular structural and thermal effects on the solid-like and liquid-like behaviors of PFPEs. The temperature dependence of the endgroup agglomeration phenomena was examined, where the functional endgroups are decoupled as the temperature increases. By analyzing the relaxation processes, the molecular rheological studies will provide the optimal lubricant selection criteria to enhance the HDD performance and reliability for the heat-assisted magnetic recording applications.

  9. Non-equilibrium responses of PFPE lubricants with various atomistic/molecular architecture at elevated temperature

    Directory of Open Access Journals (Sweden)

    Pil Seung Chung

    2017-05-01

    Full Text Available During the operation of hard disk drive (HDD, the perfluoropolyether (PFPE lubricant experiences elastic or viscous shear/elongation deformations, which affect the performance and reliability of the HDD. Therefore, the viscoelastic responses of PFPE could provide a finger print analysis in designing optimal molecular architecture of lubricants to control the tribological phenomena. In this paper, we examine the rheological responses of PFPEs including storage (elastic and loss (viscous moduli (G′ and G″ by monitoring the time-dependent-stress-strain relationship via non-equilibrium molecular dynamics simulations. We analyzed the rheological responses by using Cox-Merz rule, and investigated the molecular structural and thermal effects on the solid-like and liquid-like behaviors of PFPEs. The temperature dependence of the endgroup agglomeration phenomena was examined, where the functional endgroups are decoupled as the temperature increases. By analyzing the relaxation processes, the molecular rheological studies will provide the optimal lubricant selection criteria to enhance the HDD performance and reliability for the heat-assisted magnetic recording applications.

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  11. Vapor pressures and vapor compositions in equilibrium with hypostoichiometric uranium-plutonium dioxide at high temperatures

    International Nuclear Information System (INIS)

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

    1982-01-01

    Vapor pressures and vapor compositions in equilibrium with a hypostoichiometric uranium-plutonium dioxide condensed phase (U/sub 1-y/Pu/sub y/)O/sub 2-x/, as functions of T, x, and y, have been calculated for 0.0 less than or equal to x less than or equal to 0.1, 0.0 less than or equal to y less than or equal to 0.3, and for the temperature range 2500 less than or equal to T less than or equal to 6000 K. The range of compositions and temperatures was limited to the region of interest to reactor safety analysis. Thermodynamic functions for the condensed phase and for each of the gaseous species were combined with an oxygen potential model to obtain partial pressures of O, O 2 , Pu, PuO, PuO 2 , U, UO, UO 2 , and UO 3 as functions of T, x, and y

  12. Ammonia IR Absorbance Measurements with an Equilibrium Vapor Cell

    National Research Council Canada - National Science Library

    Field, Paul

    2004-01-01

    Infrared (IR) absorbance spectra were acquired for 18 ammonia vapor pressures. The vapor pressures were generated with 15 gravimetrically prepared aqueous solutions and three commercial aqueous solutions using a dynamic method I.E...

  13. Vapor-Liquid Equilibrium of Methane with Water and Methanol. Measurements and Modeling

    DEFF Research Database (Denmark)

    Frost, Michael Grynnerup; Karakatsani, Eirini; von Solms, Nicolas

    2014-01-01

    that rely on phase equilibrium data for optimization. The objective of this work is to provide experimental data for hydrocarbon systems with polar chemicals such as alcohols, glycols, and water. New vapor-liquid equilibrium data are reported for methane + water, methane + methanol, and methane + methanol...

  14. Prediction of the liquid-vapor equilibrium pressure using the quasi-Gaussian entropy theory

    NARCIS (Netherlands)

    Amadei, A; Roccatano, D; Apol, M.E F; Berendsen, H.J.C.; Di Nola, A.

    1996-01-01

    We derived a method to evaluate the liquid-vapor equilibrium pressure, with high accuracy over a large range of temperature, using the quasi-Gaussian entropy theory. The final expression that we obtain for the equilibrium pressure as a function of the temperature can be considered as a very accurate

  15. Vapor-liquid equilibrium thermodynamics of N2 + CH4 - Model and Titan applications

    Science.gov (United States)

    Thompson, W. R.; Zollweg, John A.; Gabis, David H.

    1992-01-01

    A thermodynamic model is presented for vapor-liquid equilibrium in the N2 + CH4 system, which is implicated in calculations of the Titan tropospheric clouds' vapor-liquid equilibrium thermodynamics. This model imposes constraints on the consistency of experimental equilibrium data, and embodies temperature effects by encompassing enthalpy data; it readily calculates the saturation criteria, condensate composition, and latent heat for a given pressure-temperature profile of the Titan atmosphere. The N2 content of condensate is about half of that computed from Raoult's law, and about 30 percent greater than that computed from Henry's law.

  16. Stability limit of liquid water in metastable equilibrium with subsaturated vapors.

    Science.gov (United States)

    Wheeler, Tobias D; Stroock, Abraham D

    2009-07-07

    A pure liquid can reach metastable equilibrium with its subsaturated vapor across an appropriate membrane. This situation is analogous to osmotic equilibrium: the reduced chemical potential of the dilute phase (the subsaturated vapor) is compensated by a difference in pressure between the phases. To equilibrate with subsaturated vapor, the liquid phase assumes a pressure that is lower than its standard vapor pressure, such that the liquid phase is metastable with respect to the vapor phase. For sufficiently subsaturated vapors, the liquid phase can even assume negative pressures. The appropriate membrane for this metastable equilibrium must provide the necessary mechanical support to sustain the difference in pressure between the two phases, limit nonhomogeneous mechanisms of cavitation, and resist the entry of the dilutant (gases) into the pure phase (liquid). In this article, we present a study of the limit of stability of liquid water--the degree of subsaturation at which the liquid cavitates--in this metastable state within microscale voids embedded in hydrogel membranes. We refer to these structures as vapor-coupled voids (VCVs). In these VCVs, we observed that liquid water cavitated when placed in equilibrium with vapors of activity aw,vapairhumiditynucleation theory or molecular simulations (Pcav=-140 to -180 MPa). To determine the cause of the disparity between the observed and predicted stability limit, we examine experimentally the likelihood of several nonhomogeneous mechanisms of nucleation: (i) heterogeneous nucleation caused by hydrophobic patches on void walls, (ii) nucleation caused by the presence of dissolved solute, (iii) nucleation caused by the presence of pre-existing vapor nuclei, and (iv) invasion of air through the hydrogel membrane into the voids. We conclude that, of these possibilities, (i) and (ii) cannot be discounted, whereas (iii) and (iv) are unlikely to play a role in determining the stability limit.

  17. Quaternary isobaric (vapor + liquid + liquid) equilibrium and (vapor + liquid) equilibrium for the system (water + ethanol + cyclohexane + heptane) at 101.3 kPa

    International Nuclear Information System (INIS)

    Pequenin, Ana; Asensi, Juan Carlos; Gomis, Vicente

    2011-01-01

    Highlights: → Water-ethanol-cyclohexane-heptane and water-cyclohexane-heptane isobaric VLLE. → Isobaric experimental data were determined at 101.3 kPa. → A dynamic recirculating still with an ultrasonic homogenizer was used. → The quaternary system does not present quaternary azeotropes. - Abstract: Experimental isobaric (vapor + liquid + liquid) and (vapor + liquid) equilibrium data for the ternary system {water (1) + cyclohexane (2) + heptane (3)} and the quaternary system {water (1) + ethanol (2) + cyclohexane (3) + heptane (4)} were measured at 101.3 kPa. An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer was used to determine the VLLE. The results obtained show that the system does not present quaternary azeotropes. The point-by-point method by Wisniak for testing the thermodynamic consistency of isobaric measurements was used to test the equilibrium data.

  18. Removal of cobalt from lubricant oil by the use of bentonite: equilibrium, kinetic and adsorption preliminary studies

    Energy Technology Data Exchange (ETDEWEB)

    Cuccia, Valeria; Seles, Sandro R.N.; Ladeira, Ana Cláudia Queiroz, E-mail: vc@cdtn.br, E-mail: seless@cdtn.br, E-mail: acql@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-11-01

    Radionuclides may contaminate lubricant oils in nuclear power plants. In Brazil, this kind of waste has been stored in the generator's facilities, awaiting treatment alternatives. This work intends to investigate a process to treat it for final deposition, using bentonite as sorbent material. This process will result in decontaminated oil, free from radiological control, and radioactive loaded sorbent, with considerable volume reduction of the radioactive waste. The study focuses in cobalt removal from a simulated oil waste (non-active). The production of the simulated waste is described. Bentonite was used for equilibrium time determination, kinetic and adsorption studies. Cobalt adsorption equilibrium was rapidly attained after 30 minutes. The data was used for modelling the system's kinetic, applying the pseudo first and pseudo second order equation models. Experimental data fitted to pseudo second order model, supporting the assumption that the adsorption is due to chemisorption. Batch sorption tests were conducted and the results fitted to Langmuir and Freundlich sorption models. Both isotherm models chosen for this work did not fit to the experimental data. Thus, these are preliminary results and the studies must be repeated to evaluate data variability and better statistical inference. Other isotherm models must be evaluated to choose the best fitted one and describe the sorption of cobalt on bentonite in oil matrix. Even though, bentonite has considerable potential as sorbent for the removal of cobalt from lubricant oil. Finally, the results might be extended to other kinds of radioactive oils and radioactive organic wastes. (author)

  19. Correlation of vapor - liquid equilibrium data for acetic acid - isopropanol - water - isopropyl acetate mixtures

    Directory of Open Access Journals (Sweden)

    B. A. Mandagarán

    2006-03-01

    Full Text Available A correlation procedure for the prediction of vapor - liquid equilibrium of acetic acid - isopropanol - water - isopropyl acetate mixtures has been developed. It is based on the NRTL model for predicting liquid activity coefficients, and on the Hayden-O'Connell second virial coefficients for predicting the vapor phase of systems containing association components. When compared with experimental data the correlation shows a good agreement for binary and ternary data. The correlation also shows good prediction for reactive quaternary data.

  20. Comparison of a model vapor deposited glass films to equilibrium glass films

    Science.gov (United States)

    Flenner, Elijah; Berthier, Ludovic; Charbonneau, Patrick; Zamponi, Francesco

    Vapor deposition of particles onto a substrate held at around 85% of the glass transition temperature can create glasses with increased density, enthalpy, kinetic stability, and mechanical stability compared to an ordinary glass created by cooling. It is estimated that an ordinary glass would need to age thousands of years to reach the kinetic stability of a vapor deposited glass, and a natural question is how close to the equilibrium is the vapor deposited glass. To understand the process, algorithms akin to vapor deposition are used to create simulated glasses that have a higher kinetic stability than their annealed counterpart, although these glasses may not be well equilibrated either. Here we use novel models optimized for a swap Monte Carlo algorithm in order to create equilibrium glass films and compare their properties with those of glasses obtained from vapor deposition algorithms. This approach allows us to directly assess the non-equilibrium nature of vapor-deposited ultrastable glasses. Simons Collaboration on Cracking the Glass Problem and NSF Grant No. DMR 1608086.

  1. Thermodynamic and structure-property study of liquid-vapor equilibrium for aroma compounds.

    Science.gov (United States)

    Tromelin, Anne; Andriot, Isabelle; Kopjar, Mirela; Guichard, Elisabeth

    2010-04-14

    Thermodynamic parameters (T, DeltaH degrees , DeltaS degrees , K) were collected from the literature and/or calculated for five esters, four ketones, two aldehydes, and three alcohols, pure compounds and compounds in aqueous solution. Examination of correlations between these parameters and the range values of DeltaH degrees and DeltaS degrees puts forward the key roles of enthalpy for vaporization of pure compounds and of entropy in liquid-vapor equilibrium of compounds in aqueous solution. A structure-property relationship (SPR) study was performed using molecular descriptors on aroma compounds to better understand their vaporization behavior. In addition to the role of polarity for vapor-liquid equilibrium of compounds in aqueous solution, the structure-property study points out the role of chain length and branching, illustrated by the correlation between the connectivity index CHI-V-1 and the difference between T and log K for vaporization of pure compounds and compounds in aqueous solution. Moreover, examination of the esters' enthalpy values allowed a probable conformation adopted by ethyl octanoate in aqueous solution to be proposed.

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

    Science.gov (United States)

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

    2013-12-01

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

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  4. The performance of simulated annealing in parameter estimation for vapor-liquid equilibrium modeling

    Directory of Open Access Journals (Sweden)

    A. Bonilla-Petriciolet

    2007-03-01

    Full Text Available In this paper we report the application and evaluation of the simulated annealing (SA optimization method in parameter estimation for vapor-liquid equilibrium (VLE modeling. We tested this optimization method using the classical least squares and error-in-variable approaches. The reliability and efficiency of the data-fitting procedure are also considered using different values for algorithm parameters of the SA method. Our results indicate that this method, when properly implemented, is a robust procedure for nonlinear parameter estimation in thermodynamic models. However, in difficult problems it still can converge to local optimums of the objective function.

  5. Equilibrium vapor-liquid-crystal in Sn-In-P system

    International Nuclear Information System (INIS)

    Ermilin, V.N.; Selin, A.A.; Khukhryanskij, Yu.P.

    1991-01-01

    Using flow method the dependence of phosphorus vapor pressure was investigated on the composition of equilibrium with indium phosphide crystal of Sn-In-P system melt (x P l ≤x In l ) and temperature (in the range 918 to 978 K). Its multiplicative character conditioned by change in phosphorus solubility in liquid phase and reconstruction of internal structure of the melt was established. It is revealed that in the considered melts phosphorus is in atomic form (possible as In n P complexes)

  6. A kinetic and equilibrium analysis of silicon carbide chemical vapor deposition on monofilaments

    Science.gov (United States)

    Gokoglu, S. A.; Kuczmarski, M. A.

    1993-01-01

    Chemical kinetics of atmospheric pressure silicon carbide (SiC) chemical vapor deposition (CVD) from dilute silane and propane source gases in hydrogen is numerically analyzed in a cylindrical upflow reactor designed for CVD on monofilaments. The chemical composition of the SiC deposit is assessed both from the calculated total fluxes of carbon and silicon and from chemical equilibrium considerations for the prevailing temperatures and species concentrations at and along the filament surface. The effects of gas and surface chemistry on the evolution of major gas phase species are considered in the analysis.

  7. Equilibrium chemical vapor deposition growth of Bernal-stacked bilayer graphene.

    Science.gov (United States)

    Zhao, Pei; Kim, Sungjin; Chen, Xiao; Einarsson, Erik; Wang, Miao; Song, Yenan; Wang, Hongtao; Chiashi, Shohei; Xiang, Rong; Maruyama, Shigeo

    2014-11-25

    Using ethanol as the carbon source, self-limiting growth of AB-stacked bilayer graphene (BLG) has been achieved on Cu via an equilibrium chemical vapor deposition (CVD) process. We found that during this alcohol catalytic CVD (ACCVD) a source-gas pressure range exists to break the self-limitation of monolayer graphene on Cu, and at a certain equilibrium state it prefers to form uniform BLG with a high surface coverage of ∼94% and AB-stacking ratio of nearly 100%. More importantly, once the BLG is completed, this growth shows a self-limiting manner, and an extended ethanol flow time does not result in additional layers. We investigate the mechanism of this equilibrium BLG growth using isotopically labeled (13)C-ethanol and selective surface aryl functionalization, and results reveal that during the equilibrium ACCVD process a continuous substitution of graphene flakes occurs to the as-formed graphene and the BLG growth follows a layer-by-layer epitaxy mechanism. These phenomena are significantly in contrast to those observed for previously reported BLG growth using methane as precursor.

  8. Vaporization of the prototypical ionic liquid BMImNTf₂ under equilibrium conditions: a multitechnique study.

    Science.gov (United States)

    Brunetti, Bruno; Ciccioli, Andrea; Gigli, Guido; Lapi, Andrea; Misceo, Nicolaemanuele; Tanzi, Luana; Vecchio Ciprioti, Stefano

    2014-08-07

    The vaporization behaviour and thermodynamics of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide (BMImNTf2) were studied by combining the Knudsen Effusion Mass Loss (KEML) and Knudsen Effusion Mass Spectrometry (KEMS) techniques. KEML studies were carried out in a large temperature range (398-567) K by using effusion orifices with 0.3, 1, and 3 mm diameters. The vapor pressures so measured revealed no kinetically hindered vaporization effects and provided second-law vaporization enthalpies at the mean experimental temperatures in close agreement with literature. By exploiting the large temperature range covered, the heat capacity change associated with vaporization was estimated, resulting in a value of -66.8 J K(-1) mol(-1), much lower than that predicted from calorimetric measurements on the liquid phase and theoretical calculations on the gas phase. The conversion of the high temperature vaporization enthalpy to 298 K was discussed and the value Δ(l)(g)H(m)(298 K) = (128.6 ± 1.3) kJ mol(-1) assessed on the basis of data from literature and present work. Vapor pressure data were also processed by the third-law procedure using different estimations for the auxiliary thermal functions, and a Δ(l)(g)H(m)(298 K) consistent with the assessed value was obtained, although the overall agreement is sensitive to the accuracy of heat capacity data. KEMS measurements were carried out in the lower temperature range (393-467) K and showed that the largely prevailing ion species is BMIm(+), supporting the common view of BMImNTf2 vaporizing as individual, neutral ion pairs also under equilibrium conditions. By monitoring the mass spectrometric signal of this ion as a function of temperature, a second-law Δ(l)(g)H(m)(298 K) of 129.4 ± 7.3 kJ mol(-1) was obtained, well consistent with KEML and literature results. Finally, by combining KEML and KEMS measurements, the electron impact ionization cross section of BMIm(+) was estimated.

  9. Vapor-liquid equilibrium of ethanol/ethyl acetate mixture in ultrasonic intensified environment

    Energy Technology Data Exchange (ETDEWEB)

    Mahdi, Taha; Ahmad, Arshad; Ripin, Adnan Nasef; Mohamed, Mahmoud [Universiti Teknologi Malaysia, Johor Bahru (Malaysia)

    2014-05-15

    A vapor-liquid equilibrium (VLE) study was conducted on ethanol/ethylacetate mixture as a preliminary step towards developing an ultrasonic-assisted distillation process for separating azeotropic mixtures. The influence of ultrasonic intensity and frequency on the vapor-liquid equilibrium (VLE) of the mixture was examined using a combination of four ultrasonic intensities in range of 100-400W/cm{sup 2} and three frequencies ranging from 25-68 kHz. The sonication was found to have significant impacts on the VLE of the system as it alters both the relative volatility and azeotrope point, with preference to lower frequency operation. A maximum relative volatility of 2.32 was obtained at an intensity of 300 W/cm{sup 2} and a frequency of 25 kHz coupled with complete elimination of ethanol-ethyl acetate azeotrope. Results from this work were also congruent with some experimental and theoretical works presented in the literature. These findings set a good beginning towards the development of an ultrasonic assisted distillation that is currently in progress.

  10. High Pressure Vapor-Liquid Equilibrium of Supercritical Carbon Dioxide + n-Hexane System

    Institute of Scientific and Technical Information of China (English)

    YU Jinglin; TIAN Yiling; ZHU Rongjiao; LIU Zhihua

    2006-01-01

    Vapor-liquid equilibrium data of supercritical carbon dioxide + n-hexane system were measured at 313.15 K,333.15 K,353.15 K,and 373.15 K and their molar volumes and densities were measured both in the subcritical and supercritical regions ranging from 2.15 to 12.63 MPa using a variable-volume autoclave.The thermodynamic properties including mole fractions,densities,and molar volumes of the system were calculated with an equation of state by Heilig and Franck,in which a repulsion term and a square-well potential attraction term for intermolecular interaction was used.The pairwise combination rule was used to calculate the square-well molecular interaction potential and three adjustable parameters (ω,kε,kσ) were obtained.The Heilig-Franck equation of state is found to have good correlation with binary vapor-liquid equilibrium data of the carbon dioxide + n-hexane system.

  11. Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing

    DEFF Research Database (Denmark)

    Sepe, Alessandro; Zhang, Jianqi; Perlich, Jan

    2016-01-01

    Solvent vapor annealing (SVA) is frequently used to improve the ordering in diblock copolymer thin films. An important question is which SVA protocol should be chosen to ensure thermodynamic equilibrium. Here, we investigate two thin films from a low molar-mass, lamellae-forming polystyrene....... SVA cycles were carried out with cyclohexane, and the structural changes were followed in-situ using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). Before and after SVA, Dlam,par is significantly lower than in the bulk, i.e. the equi-librium value of Dlam,par in thin film...... glassy again, affinely. During the second SVA cycle on the thin film, the scaling behavior of the lamellar thickness is identical to the one during the first drying and to the drying behavior of the thicker film. We conclude that one cycle of solvent vapor treatment with a degree of swelling of ca. 1...

  12. Vapor-liquid equilibrium of ethanol/ethyl acetate mixture in ultrasonic intensified environment

    International Nuclear Information System (INIS)

    Mahdi, Taha; Ahmad, Arshad; Ripin, Adnan Nasef; Mohamed, Mahmoud

    2014-01-01

    A vapor-liquid equilibrium (VLE) study was conducted on ethanol/ethylacetate mixture as a preliminary step towards developing an ultrasonic-assisted distillation process for separating azeotropic mixtures. The influence of ultrasonic intensity and frequency on the vapor-liquid equilibrium (VLE) of the mixture was examined using a combination of four ultrasonic intensities in range of 100-400W/cm 2 and three frequencies ranging from 25-68 kHz. The sonication was found to have significant impacts on the VLE of the system as it alters both the relative volatility and azeotrope point, with preference to lower frequency operation. A maximum relative volatility of 2.32 was obtained at an intensity of 300 W/cm 2 and a frequency of 25 kHz coupled with complete elimination of ethanol-ethyl acetate azeotrope. Results from this work were also congruent with some experimental and theoretical works presented in the literature. These findings set a good beginning towards the development of an ultrasonic assisted distillation that is currently in progress

  13. Lubrication fundamentals

    CERN Document Server

    Pirro, DM

    2001-01-01

    This work discusses product basics, machine elements that require lubrication, methods of application, lubricant storage and handling, and lubricant conservation. This edition emphasizes the need for lubrication and careful lubricant selection.

  14. Phase Equilibrium of TiO2 Nanocrystals in Flame-Assisted Chemical Vapor Deposition.

    Science.gov (United States)

    Liu, Changran; Camacho, Joaquin; Wang, Hai

    2018-01-19

    Nano-scale titanium oxide (TiO 2 ) is a material useful for a wide range of applications. In a previous study, we showed that TiO 2 nanoparticles of both rutile and anatase crystal phases could be synthesized over the size range of 5 to 20 nm in flame-assisted chemical vapor deposition. Rutile was unexpectedly dominant in oxygen-lean synthesis conditions, whereas anatase is the preferred phase in oxygen-rich gases. The observation is in contrast to the 14 nm rutile-anatase crossover size derived from the existing crystal-phase equilibrium model. In the present work, we made additional measurements over a wider range of synthesis conditions; the results confirm the earlier observations. We propose an improved model for the surface energy that considers the role of oxygen desorption at high temperatures. The model successfully explains the observations made in the current and previous work. The current results provide a useful path to designing flame-assisted chemical vapor deposition of TiO 2 nanocrystals with controllable crystal phases. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Isothermal Vapor-Liquid Equilibrium in the Quaternary Water + 2-Propanol + Acetic Acid + Isopropyl Acetate System with Chemical Reaction

    Czech Academy of Sciences Publication Activity Database

    Teodorescu, M.; Aim, Karel; Wichterle, Ivan

    2001-01-01

    Roč. 46, č. 2 (2001), s. 261-266 ISSN 0021-9568 R&D Projects: GA ČR GA203/98/1446 Institutional research plan: CEZ:AV0Z4072921 Keywords : vapor-liquid equilibrium * quaternary water Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.960, year: 2001

  16. Vapor-liquid equilibrium prediction with pseudo-cubic equation of state for binary mixtures containing hydrogen, helium, or neon

    Energy Technology Data Exchange (ETDEWEB)

    Kato, M.; Tanaka, H. (Nihon Univ.,Fukushima, (Japan). Faculty of Enineering)

    1990-03-01

    As an equation of state of vapor-liquid equilibrium, an original pseudo-cubic equation of state was previously proposed by the authors of this report and its study is continued. In the present study, new effective critical values of hydrogen, helium and neon were determined empirically from vapor-liquid equilibrium data of literature values against their critical temperatures, critical pressures and critical volumes. The vapor-liquid equilibrium relations of binary system quantum gas mixtures were predicted combining the conventinal pseudo-cubic equation of state and the new effective critical values, and without using binary heteromolecular interaction parameter. The predicted values of hydrogen-ethylene, helium-propane and neon-oxygen systems were compared with literature values. As a result, it was indicated that the vapor-liquid relations of binary system mixtures containing hydrogen, helium and neon can be predicted with favorable accuracy combining the effective critical values and the three parameter pseudo-cubic equation of state. 37 refs., 3 figs., 4 tabs.

  17. The study of water + HCl + ethanol vapor-liquid equilibrium at 78 kPa

    International Nuclear Information System (INIS)

    Ojeda Toro, Juan Carlos; Dobrosz-Gómez, Izabela; Gómez García, Miguel Ángel

    2017-01-01

    Graphical abstract: Comparison between experimental and calculated saturation temperature of water + HCl + ethanol system using two rigorous electrolyte models. - Highlights: • Data for the water + HCl + ethanol VLE is reported at 78 kPa. • The VLE for the system water + HCl + ethanol was determined. • A new set of parameters for extended UNIQUAC model were correlated. • A new set of parameters for LIQUAC model were correlated. - Abstract: In this work, the isobaric vapor-liquid equilibrium (VLE) data obtained for the ternary system water + HCl + ethanol at 78 kPa, using an Ellis still, were studied. Two rigorous electrolyte models (extended UNIQUAC and LIQUAC) were fitted to the experimental data. Ethanol-H + , water-H + , ethanol-Cl − , water-Cl − , and Cl − -H + interaction parameters were determined. Likewise, Henry’s law constants for the volatile electrolyte were defined. A high goodness of fit was obtained for both electrolyte models; however, the extended UNIQUAC one showed better performance (AAD = 0.1326%). Two azeotropes observed in the system were accurately predicted (ethanol + water: x EtOH = 0.86 at 344.6 K; and HCl + water: x HCl = 0.11 at 375.5 K).

  18. Lubrication fundamentals

    International Nuclear Information System (INIS)

    Wills, J.G.

    1990-01-01

    This book is organized under the following headings: lubricating oils; lubricating greases; synthetic lubricants; machine elements; lubricant application; internal combustion engines; stationary gas turbines; steam turbines; hydraulic turbines; nuclear power plants; automotive chassis components; automotive power transmissions; compressors; handling, storing, and dispensing lubricants, in-plant handling for lubricant conservation

  19. Equilibrium water vapor pressures over polyvanadates M2V12O30.7·nH2O

    International Nuclear Information System (INIS)

    Volkov, V.L.; Zakharova, G.S.; Ivakin, A.A.

    1986-01-01

    Equilibrium pressures of water vapors over polyvanadates M 2 V 12 O 30.7 xnH 2 O where M=Li, Na, K are determined in the 293-343 K temperature range. Changes in Gibbs free energy and enthalpy of compound dehydration depending on water content in the final product are calculated on the basis of these data. Molar enthalpy of water is shown to reduce from lithium to potassium, while equilibrium pressure of water vapors over the compounds grows from lithium to potassium. Good correlation of thermodynamic properties of crystallization water of polyvanadates with energy characteristics of hydrated M + ions of the solutions confirms the conclusion that they cannot be attributed to ordinary crystallohydrates

  20. Near-equilibrium chemical vapor deposition of high-quality single-crystal graphene directly on various dielectric substrates.

    Science.gov (United States)

    Chen, Jianyi; Guo, Yunlong; Jiang, Lili; Xu, Zhiping; Huang, Liping; Xue, Yunzhou; Geng, Dechao; Wu, Bin; Hu, Wenping; Yu, Gui; Liu, Yunqi

    2014-03-05

    By using near-equilibrium chemical vapor deposition, it is demonstrated that high-quality single-crystal graphene can be grown on dielectric substrates. The maximum size is about 11 μm. The carrier mobility can reach about 5650 cm(2) V(-1) s(-1) , which is comparable to those of some metal-catalyzed graphene crystals, reflecting the good quality of the graphene lattice. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Distillation Separation of Hydrofluoric Acid and Nitric Acid from Acid Waste Using the Salt Effect on Vapor-Liquid Equilibrium

    Science.gov (United States)

    Yamamoto, Hideki; Sumoge, Iwao

    2011-03-01

    This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor-liquid equilibrium for acid aqueous solutions and acid mixtures. The vapor-liquid equilibrium of hydrofluoric acid + salt systems (fluorite, potassium nitrate, cesium nitrate) was measured using an apparatus made of perfluoro alkylvinylether. Cesium nitrate showed a salting-out effect on the vapor-liquid equilibrium of the hydrofluoric acid-water system. Fluorite and potassium nitrate showed a salting-in effect on the hydrofluoric acid-water system. Separation of hydrofluoric acid from an acid mixture containing nitric acid and hydrofluoric acid was tested by the simple distillation treatment using the salt effect of cesium nitrate (45 mass%). An acid mixture of nitric acid (5.0 mol · dm-3) and hydrofluoric acid (5.0 mol · dm-3) was prepared as a sample solution for distillation tests. The concentration of nitric acid in the first distillate decreased from 5.0 mol · dm-3 to 1.13 mol · dm-3, and the concentration of hydrofluoric acid increased to 5.41 mol · dm-3. This first distillate was further distilled without the addition of salt. The concentrations of hydrofluoric acid and nitric acid in the second distillate were 7.21 mol · dm-3 and 0.46 mol · dm-3, respectively. It was thus found that the salt effect on vapor-liquid equilibrium of acid mixtures was effective for the recycling of acids from acid mixture wastes.

  2. Pulsed Plasma Lubrication Device and Method

    Science.gov (United States)

    Hofer, Richard R. (Inventor); Bickler, Donald B. (Inventor); D'Agostino, Saverio A. (Inventor)

    2016-01-01

    Disclosed herein is a lubrication device comprising a solid lubricant disposed between and in contact with a first electrode and a second electrode dimensioned and arranged such that application of an electric potential between the first electrode and the second electrode sufficient to produce an electric arc between the first electrode and the second electrode to produce a plasma in an ambient atmosphere at an ambient pressure which vaporizes at least a portion of the solid lubricant to produce a vapor stream comprising the solid lubricant. Methods to lubricate a surface utilizing the lubrication device in-situ are also disclosed.

  3. Vapor-liquid equilibrium of the Mg(NO3)2-HNO3-H2O system

    International Nuclear Information System (INIS)

    Thompson, B.E.; Derby, J.J.; Stalzer, E.H.

    1983-06-01

    The vapor-liquid equilibrium of the Mg(NO 3 ) 2 -HNO 3 -H 2 O system in concentrations of 0 to 70 wt % Mg(NO 3 ) 2 and 0 to 75 wt % HNO 3 at atmospheric pressure was correlated by two approaches. One was based on a dissociation equilibrium expression in which the activities of the reacting species (HNO 3 , NO 3 - , and H + ) were approximated with mole fractions. The activity coefficients of the undissociated HNO 3 and H 2 O were correlated as functions of the concentrations of magnesium nitrate and nitric acid by second-order polynomials. The average absolute difference between predicted and experimental values was 8% for the mole fraction of acid in the vapor and 8 0 K for the bubble-point temperature. The second approach was to correlate the mean ionic rational activity coefficient of water with a form of the excess Gibbs energy composed of two terms. One term, a function of the ionic strength, accounts for the coulombic (ionic) interactions; the other term accounts for the non-coulombic (molecular) interactions. The average absolute difference between predicted and experimental values was 9% for the mole fraction of acid in the vapor, and 10 0 K for the bubble-point temperature

  4. A non-equilibrium model for soil heating and moisture transport during extreme surface heating: The soil (heat-moisture-vapor) HMV-Model Version

    Science.gov (United States)

    William Massman

    2015-01-01

    Increased use of prescribed fire by land managers and the increasing likelihood of wildfires due to climate change require an improved modeling capability of extreme heating of soils during fires. This issue is addressed here by developing and testing the soil (heat-moisture-vapor) HMVmodel, a 1-D (one-dimensional) non-equilibrium (liquid- vapor phase change)...

  5. Vapor-liquid equilibrium for the system ethyl alcohol + ester; Equilibrio liquido-vapor para o sistema alcool etilico+ester

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Humberto Neves Maia de; Nascimento, Yuri Corsino do; Chiavone-Filho, Osvaldo [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2004-07-01

    This work consists of the experimental determination of a series of vapor-liquid equilibrium (VLE) data, for mixtures of ethyl alcohol + ester (ethyl acetate), prepared synthetically, that may be present in the production of biodiesel. The separation of the ethyl alcohol from esters by distillation is an important stage of this process, and therefore it demands accurate data for an appropriate modelling, and later optimization via simulators. FISCHER'S ebulliometer, with digital control (Model 602), was used for measurement of VLE data for the system ethyl alcohol + ester. It consists of a recirculation cell of the both vapor and liquid phases, providing complete data, i.e., pressure, temperature and compositions of the liquid and vapor phases that were obtained by gaseous chromatography (PTxy). This apparatus is coupled to a thermostatic bath with cooling (TE-184 TECNAL) that aims to condense the coming steams of the ebullition in order to return to the mixture camera. The VLE data obtained experimentally were submitted to the test of thermodynamic consistence of the deviations, where the equation of Gibbs-Duhem is used, through the model UNIQUAC. The parameters obtained from the experimental data can be applied in the simulators of processes with the purpose of optimizing the separation of the ethyl alcohol of Ester. (author)

  6. Measurement of vapor-liquid-liquid phase equilibrium-Equipment and results

    DEFF Research Database (Denmark)

    Frost, Michael Grynnerup; von Solms, Nicolas; Richon, Dominique

    2015-01-01

    There exists a need for new accurate and reliable experimental data, preferably with full characterization of all the phases present in equilibrium. The need for high-quality experimental phase equilibrium data is the case for the chemical industry in general. All areas deal with processes whose ...

  7. Thermodynamics of the multicomponent vapor-liquid equilibrium under capillary pressure difference

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2001-01-01

    We discuss the two-phase multicomponent equilibrium, provided that the phase pressures are different due to the action of capillary forces. We prove the two general properties of such an equilibrium, which have previously been known for a single-component case, however, to the best of our knowledge......, not for the multicomponent mixtures. The importance is emphasized on the space of the intensive variables P, T and mu (i), where the laws of capillary equilibrium have a simple geometrical interpretation. We formulate thermodynamic problems specific to such an equilibrium, and outline changes to be introduced to common...... algorithms of flash calculations in order to solve these problems. Sample calculations show large variation of the capillary properties of the mixture in the very neighborhood of the phase envelope and the restrictive role of the spinodal surface as a boundary for possible equilibrium states with different...

  8. Calculation of vapor pressures of oxide fuels up to 5,000 K for equilibrium and nonequilibrium evaporation

    International Nuclear Information System (INIS)

    Breitung, W.

    1975-06-01

    In the first part of this work the evaporation kinetics of multicomponent systems is studied with UO 2 as the example. The evaporation, which is generally incongruent, implies that two opposing types of steady-state evaporation must be distinguished: equilibrium evaporation and 'forced congruent' evaporation. The two types of evaporation indicated entail different vapor pressures. In some prompt critical reactor incidents forced congruent evaporation must be anticipated. The second part of this work contains the calculation of the vapor pressures of UOsub(2+-x) and (U,Pu)Osub(2+-x) for both types of evaporation up to temperature of 5,000 K. The calculating procedures are based on the method of Rand and Markin (1967) incorporating the recent thermodynamic data. The agreement between the measured and calculated total pressures is good for the ranges of temperature and stoichiometry for which experimental results are available. This supports the results calculated for higher temperature ranges. (orig./UA) [de

  9. Vapor-Liquid Equilibrium in the Mixture 1,1-Difluoroethane C2H4F2 + C4H8 2-Methylpropene (EVLM1131, LB5730_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture 1,1-Difluoroethane C2H4F2 + C4H8 2-Methylpropene (EVLM1131, LB5730_E)' providing data from direct measurement of pressure and mole fraction in vapor phase at variable mole fraction in liquid phase and constant temperature.

  10. MOLECULAR SIMULATION OF THE VAPOR-LIQUID EQUILIBRIUM OF N2-NC5 MIXTURE BY MONTE CARLO SIMULATIONS

    Directory of Open Access Journals (Sweden)

    Florianne Castillo-Borja

    2013-12-01

    Full Text Available ABSTRACT This study used Monte Carlo simulations in the Gibbs ensemble to describe the liquid-vapor phase equilibrium of nitrogen-n-pentane system for three isotherms. The study analyzed a wide range of pressures ranging up to 25 MPa. The system was modeled using the intermolecular potential Galassi-Tildesley for nitrogen and SKS for n-pentane. Results were compared against experimental data. Far from the critical point region, analyzed models reproduce favorably shape of the curve of phase equilibrium and in the vicinity of the critical point, results tend to move away from the experimental behavior. Critical points were determined (pressure, density and composition for the three isotherms using an extrapolation method based on scaling laws, with satisfactory results. Calculated coexistence curves are adequate even if the models analyzed do not contain optimized binary interaction parameters .

  11. Liquid-vapor equilibrium and interfacial properties of square wells in two dimensions

    Science.gov (United States)

    Armas-Pérez, Julio C.; Quintana-H, Jacqueline; Chapela, Gustavo A.

    2013-01-01

    Liquid-vapor coexistence and interfacial properties of square wells in two dimensions are calculated. Orthobaric densities, vapor pressures, surface tensions, and interfacial thicknesses are reported. Results are presented for a series of potential widths λ* = 1.4, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5, where λ* is given in units of the hard core diameter σ. Critical and triple points are explored. No critical point was found for λ* Armas-Pérez et al. [unpublished] as a hexatic phase transition. It is located at reduced temperatures T* = 0.47 and 0.35 for λ* = 1.4 and 1.5, respectively. Properties such as the surface tension, vapor pressure, and interfacial thickness do not present any discontinuity at these points. This amorphous solid branch does not follow the corresponding state principle, which is only applied to liquids and gases.

  12. Oil and natural gas technology review-lubrication and lubricants

    Energy Technology Data Exchange (ETDEWEB)

    Moos, J

    1966-01-01

    A summary is presented of the advances made during 1967 in the following areas: production and transmission of natural gas; geosciences; drilling and production technology; secondary recovery; transportation by tanker, pipelines, and tank cars; storage; planning of refineries; control and automation; cracking and gasification of crude oil; separation and hydrogenation processes; petrochemicals; combustion technology; fuels and additives; air and water pollution control; production of lubricants; lubrication with mist, gas, and vapors; hydraulic fluids; lubricant additives; oxidation and aging of oils; greases; solid lubricants; bearings; machining; friction and wear; and changes in materials of construction. (220 refs.)

  13. Modeling of vapor-liquid-solid equilibrium in gas - aqueous electrolyte systems

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Rasmussen, Peter

    1999-01-01

    A thermodynamic model for the description of vapor-liquid-solid equilibria is introduced. This model is a combination of the extended UNIQUAC model for electrolytes and the Soave-Redlich-Kwong cubic equation of state. The model has been applied to aqueous systems containing ammonia and/or carbon ...

  14. High-pressure vapor-liquid equilibrium data for CO2-orange peel oil

    Directory of Open Access Journals (Sweden)

    G.R. Stuart

    2000-06-01

    Full Text Available Recently, there has been a growing interest in fractionating orange peel oil by the use of supercritical carbon dioxide (SCCO2. However, progress in this area has been hindered by the lack of more comprehensive work concerning the phase equilibrium behavior of the SCCO2-orange peel oil system. In this context, the aim of this work is to provide new phase equilibrium data for this system over a wide range of temperatures and pressures, permitting the construction of coexistence PT-xy curves as well as the P-T diagram. The experiments were performed in a high-pressure variable-volume view cell in the temperature range of 50-70ºC from 70 to 135 atm and in the CO2 mass fraction composition range of 0.35-0.98. Based on the experimental phase equilibrium results, appropriate operating conditions can be set for high-pressure fractionation purposes.

  15. Physical property, phase equilibrium, distillation. Measurement and prediction of vapor-liquid and liquid-liquid equilibria; Bussei / heiko / joryu. Kieki, ekieki heiko no sokutei to suisan

    Energy Technology Data Exchange (ETDEWEB)

    Tochigi, K. [Nihon Univ., Tokyo (Japan)

    1998-08-05

    The data on vapor-liquid equilibrium are basic data indispensable to the designing of a distillation process. The stage required for separation depends greatly upon the x-y curve, and the existence/nonexistence of an azeotropic point is also an important item to be checked. This paper describes the measurement of vapor-liquid equilibrium and liquid-liquid equilibrium, and then introduces reliable data on vapor-liquid equilibrium and parameters of an activity coefficient formula. For the prediction of vapor-liquid equilibrium, the ASOG, UNIFAC, and modified NIFAC, all being group contributive methods are utilized. The differences between these group contributive methods are based on the differences between the contributive items based on the differences in size of molecules influencing the activity coefficients and the expression of the group activity coefficient formula. The applicable number of groups of the ASOG is 43, while that of groups of the UNIFAC is 50. The modified UNIFAC covers 43 groups. The prediction of liquid-liquid equilibrium by using a group contributive method has little progressed since the of the results of the study of Magnussen et al. using the UNIFAC. 12 refs., 8 figs., 1 tab.

  16. Vapor-Liquid Equilibrium Measurements and Modeling of the Propyl Mercaptan plus Methane plus Water System

    DEFF Research Database (Denmark)

    Awan, Javeed; Thomsen, Kaj; Coquelet, Christophe

    2010-01-01

    In this work, vapor−liquid equilibrium (VLE) measurements of propyl mercaptan (PM) in pure water were performed at three different temperatures, (303, 323, and 365) K, with a pressure variation from (1 to 8) MPa. The total system pressure was maintained by CH4. The inlet mole fraction of propyl...

  17. Study of the liquid vapor equilibrium in the bromine-hydrobromic acid-water system

    Science.gov (United States)

    Benizri, R.; Lessart, P.; Courvoisier, P.

    1984-01-01

    A glass ebullioscope was built and at atmospheric pressure, liquid-vapor equilibria relative to the Br2-HBr-H2O system, in the concentration range of interest for evaluation of the Mark 13 cycle was studied. Measurements were performed for the brome-azeotrope (HBr-H2O) pseudo-binary system and for the ternary system at temperatures lower than 125 C and in the bromine concentration range up to 13% wt.

  18. Ice-vapor equilibrium fractionation factor of hydrogen and oxygen isotopes

    DEFF Research Database (Denmark)

    Ellehøj, Mads Dam; Steen-Larsen, Hans Christian; Johnsen, Sigfus Johann

    2013-01-01

    RATIONALE: The equilibrium fractionation factors govern the relative change in the isotopic composition during phase transitions of water. The commonly used results, which were published more than 40 years ago, are limited to a minimum temperature of -33 degrees C. This limits the reliability...... values, with a temperature dependency in accordance with theory for equilibrium fractionation. We obtain the following expressions for the temperature dependency of the fractionation coefficients: ln(alpha(delta 2H)) = 0.2133 - 203.10/T + 48888/T-2 ln(alpha(delta 18O)) = 0.0831 - 49.192/T + 8312.5/T2...... Compared with previous experimental work, a significantly larger for H-2 is obtained while, for O-18, is larger for temperatures below -20 degrees C and slightly lower for temperatures above this. CONCLUSIONS: Using the new values for alpha, a Rayleigh distillation model shows significant changes in both...

  19. Comparison of molecular models of carbon monoxide for calculation of vapor-liquid equilibrium

    Directory of Open Access Journals (Sweden)

    Bibian Alonso Hoyos-Madrigal

    2015-01-01

    Full Text Available Existen varios modelos moleculares para el monóxido de carbono desarrollados a partir de diferentes mediciones experimentales. El objetivo de este trabajo es comparar los resultados que varios de estos modelos producen en el cálculo del equilibrio líquido-vapor en busca de recomendar qué modelo debe ser usado de acuerdo la propiedad y la fase que se desea calcular. Los modelos seleccionados corresponden a cuatro modelos no polares, con uno o dos sitios Lennard-Jones, y cuatro modelos polares, con dipolos o cargas parciales para representar la polaridad del monóxido de carbono. Simulaciones Monte Carlo en la versión Gibbs canónica (NVT-GEMC se emplearon para determinar las densidades de las fases en equilibrio, la presión de vapor y la entalpia de vaporización entre 80 y 130 K con cada uno de los modelos seleccionados. Se encontró que los modelos más complejos SVH, ANC y PGB, son los que mejor describen la densidad del líquido saturado (alrededor de 7% de desviación promedio, pero estos modelos generan desviaciones mayores al 40% para las propiedades del vapor y al 20% para la entalpia de vaporización. Por otro lado, el modelo no- polar BLF generó las menores desviaciones para la presión de saturación y la densidad del vapor (6.8 y 21.5%, respectivamente. Este modelo, al igual que el modelo HCB, produce desviaciones aceptables para la densidad del líquido y la entalpia de vaporización (entre 10 y 12%. Los modelos no polares BLF y HCB, que no requieren el cálculo de las interacciones de largo alcance, se pueden considerar como los modelos moleculares que presentan un balance satisfactorio entre desviaciones en los resultados y complejidad de cálculo.

  20. Predicting the growth of S i3N4 nanowires by phase-equilibrium-dominated vapor-liquid-solid mechanism

    Science.gov (United States)

    Zhang, Yongliang; Cai, Jing; Yang, Lijun; Wu, Qiang; Wang, Xizhang; Hu, Zheng

    2017-09-01

    Nanomaterial synthesis is experiencing a profound evolution from empirical science ("cook-and-look") to prediction and design, which depends on the deep insight into the growth mechanism. Herein, we report a generalized prediction of the growth of S i3N4 nanowires by nitriding F e28S i72 alloy particles across different phase regions based on our finding of the phase-equilibrium-dominated vapor-liquid-solid (PED-VLS) mechanism. All the predictions about the growth of S i3N4 nanowires, and the associated evolutions of lattice parameters and geometries of the coexisting Fe -Si alloy phases, are experimentally confirmed quantitatively. This progress corroborates the general validity of the PED-VLS mechanism, which could be applied to the design and controllable synthesis of various one-dimensional nanomaterials.

  1. Collision cross sections and equilibrium fractions of ions and atoms in metal vapor targets. Project progress report, June 1, 1979-May 31, 1980

    International Nuclear Information System (INIS)

    Morgan, T.J.

    1980-01-01

    The objective of this program is to measure atomic collision cross sections and equilibrium fractions of ions and atoms in metal vapor targets. The goal is to obtain experimental information on atomic collision processes relevant to the Magnetic Fusion Energy Program. In particular, in connection with the development of double charge exchange D - ion sources, we are measuring D - formation cross sections in alkaline-earth metal vapor targets. During the period covered in this report we have measured electron transfer cross sections for 3-40 keV D + ions and D 0 atoms in collision with calcium vapor

  2. Vapor-liquid equilibrium and critical asymmetry of square well and short square well chain fluids.

    Science.gov (United States)

    Li, Liyan; Sun, Fangfang; Chen, Zhitong; Wang, Long; Cai, Jun

    2014-08-07

    The critical behavior of square well fluids with variable interaction ranges and of short square well chain fluids have been investigated by grand canonical ensemble Monte Carlo simulations. The critical temperatures and densities were estimated by a finite-size scaling analysis with the help of histogram reweighting technique. The vapor-liquid coexistence curve in the near-critical region was determined using hyper-parallel tempering Monte Carlo simulations. The simulation results for coexistence diameters show that the contribution of |t|(1-α) to the coexistence diameter dominates the singular behavior in all systems investigated. The contribution of |t|(2β) to the coexistence diameter is larger for the system with a smaller interaction range λ. While for short square well chain fluids, longer the chain length, larger the contribution of |t|(2β). The molecular configuration greatly influences the critical asymmetry: a short soft chain fluid shows weaker critical asymmetry than a stiff chain fluid with same chain length.

  3. Determination of antioxidants in new and used lubricant oils by headspace-programmed temperature vaporization-gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nogal Sanchez, Miguel del; Perez Pavon, Jose Luis; Garcia Pinto, Carmelo; Moreno Cordero, Bernardo [Universidad de Salamanca, Departamento de Quimica Analitica, Nutricion y Bromatologia, Salamanca (Spain); Glanzer, Paul [University of Vienna, Department of Analytical Chemistry, Vienna (Austria)

    2010-12-15

    A sensitive method is presented to determine antioxidants (2-, 3-, and 4-tert-butylphenol, 2,6-di-tert-butylphenol, 3-tert-butyl-4-hydroxyanisol, 2,6-di-tert-butyl-4-methylphenol, 1-naphthol, and diphenylamine) in new and used lubricant oil samples. Research was carried out on a GC device equipped with a headspace sampler, a programmed temperature vaporizer, and an MS detector unit. The proposed method does not require sample treatment prior to analyses, hence eliminating possible errors occurring in this step. Sample preparation is reduced when placing the oil sample (2.0 g) in the vial and adding propyl acetate (20 {mu}L). Solvent vent injection mode permits a pre-concentration of the compounds of interest in the liner filled with Tenax-TA {sup registered}, while venting other species present in the headspace. Thereby, both the life of the liner and the capillary column is prolonged, and unnecessary contamination of the detector unit is avoided. Calibration was performed by adding different concentrations of analytes to a new oil which did not contain any of the studied compounds. Limits of detection as low as 0.57 {mu}g/L (2-tert-butylphenol) with a precision lower or equal to 5.3% were achieved. Prediction of the antioxidants in new oil samples of different viscosities (5W40, 10W40, and 15W40) was accomplished with the previous calibration, and the results were highly satisfactory. To determine antioxidants in used engine oils, standard addition method was used due to the matrix effect. (orig.)

  4. Liquid-vapor equilibrium in VOCl3-Si2OCl6 and VOCl3-CCl3COCl systems

    International Nuclear Information System (INIS)

    Tret'yakova, K.V.

    1976-01-01

    Two methods were used in a study of liquid-vapor equilibrium of VOCl 3 -Si 2 OCl 6 (1) and VOCl 3 -CCl 3 COCl (2) systems. The first, ebulliometric method was used for determining the relationship saturated vapor pressure in the range from 450-500 to 1450-1500 mm Hg and the temperature which is in the range from 100-110 to 150-160 deg C. The data on saturated vapor pressure of pure substances and their mixtures were interpreted by the least squares method according to an equations of the type lgP=A-B/T. For 760 mm Hg isobar the dependence of the b.p. of system 1 on the concentration of its components considerably deviates fron the ideal state. In this case positive azeotrope is formed (b.p. 126.5 deg C) containing 83.5% mole VOCl 3 . The Van Laar euqation was used in calculating the relative volatility. At 760 mm Hg pressure in I, Si 2 OCl 6 is more volatile, the difference between the normal b.p. of VOCl 6 (127.7 deg C) and that of the azeotropic mixture (126.5 deg C) being only 1.2 deg C. The Rayleigh distillation method was used for direct determination of the volatility of this system. The average value for αsub(Si 2 OCl 6 /VOCl 3 ) was found to be 1.44. It accords well with the value of 1.47 obtained from an extrapolation of results for pure VOCl 3 on the basis of the ebulloimetric measurements. In the case of system 2 a considerable positive deviation from the ideal state was observed within the entire range of concentrations. Calculations of the activity coefficients for the components of this system, the composition of the vapor phase and the relative volatility were made with the aid of the Dugem-Margulis equation. The value for the relative volatility αsub(CCl 3 COCl/VOCl 3 ), as extrapolated for pure VOCl 3 , was 1.8. No direct measurements of α were made in this case owing to difficulties in analysis of the two components

  5. Identifying Liquid-Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on Pressure-Temperature Diagrams of a Mixed Gas Involving Liquid-Vapor Equilibrium

    Science.gov (United States)

    Yoshikawa, Masahiro; Koga, Nobuyoshi

    2016-01-01

    This study focuses on students' understandings of a liquid-gas system with liquid-vapor equilibrium in a closed system using a pressure-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…

  6. Multi-component vapor-liquid equilibrium model for LES of high-pressure fuel injection and application to ECN Spray A

    NARCIS (Netherlands)

    Matheis, Jan; Hickel, S.

    2018-01-01

    We present and evaluate a two-phase model for Eulerian large-eddy simulations (LES) of liquid-fuel injection and mixing at high pressure. The model is based on cubic equations of state and vapor-liquid equilibrium calculations and can represent the coexistence of supercritical states and

  7. Vapor-liquid equilibrium ratio of trace furfural in water+1-butanol system; Mizu+1-butanorukei ni okeru biryo no furufuraru no kieki heikohi

    Energy Technology Data Exchange (ETDEWEB)

    Ikari, A.; Hatate, Y.; Aikou, R. [Kagoshima Univ. (Japan). Faculty of Engineering

    1997-11-01

    Vapor-liquid equilibria of a water + 1-butanol system containing a trace amount of furfural were measured at atmospheric pressure by use of a Iino-type still for systems of limited miscibility. Vapor-liquid compositions for the major components (water and 1-butanol) are shown to be nearly coincident with those of the binary system. In the partially miscible region, the vapor-liquid equilibrium ratios of the trace component (furfural) at bubble point were found to be 2.5 and 0.46. Consequently, the partition coefficient of the trace component between the two liquid phases is 5.4. The equilibrium ratio curve of the trace component is presented, in which the calculated curve within the partially miscible region is shown to be coincident with the experimental data. 5 refs., 3 figs., 1 tab.

  8. HIGH-PRESSURE VAPOR-LIQUID EQUILIBRIUM DATA FOR BINARY AND TERNARY SYSTEMS FORMED BY SUPERCRITICAL CO2, LIMONENE AND LINALOOL

    Directory of Open Access Journals (Sweden)

    MELO S. A. B. VIEIRA DE

    1999-01-01

    Full Text Available The feasibility of deterpenating orange peel oil with supercritical CO2 depends on relevant vapor-liquid equilibrium data because the selectivity of this solvent for limonene and linalool (the two key components of the oil is of crucial importance. The vapor-liquid equilibrium data of the CO2-limonene binary system was measured at 50, 60 and 70oC and pressures up to 10 MPa, and of the CO2-linalool binary system at 50oC and pressures up to 85 bar. These results were compared with published data when available in the literature. The unpublished ternary phase equilibrium of CO2-limonene-linalool was studied at 50oC and up to 9 MPa. Selectivities obtained using these ternary data were compared with those calculated using binary data and indicate that a selective separation of limonene and linalool can be achieved.

  9. Experimental determination of the (vapor + liquid) equilibrium data of binary mixtures of fatty acids by differential scanning calorimetry

    International Nuclear Information System (INIS)

    Matricarde Falleiro, Rafael M.; Meirelles, Antonio J.A.; Kraehenbuehl, Maria A.

    2010-01-01

    (Vapor + liquid) equilibrium (VLE) data for three binary mixtures of saturated fatty acids were obtained by differential scanning calorimetry (DSC). However, changes in the calorimeter pressure cell and the use of hermetic pans with holes (φ = 250 mm) in the lids were necessary to make it possible to apply this analytical technique, obtaining accurate results with smaller samples and shorter operational times. The systems evaluated in this study were: myristic acid (C 14:0 ) + palmitic acid (C 16:0 ), myristic acid (C 14:0 ) + stearic acid (C 18:0 ), and palmitic acid (C 16:0 ) + stearic acid (C 18:0 ), all measured at 50 mm Hg and with mole fractions between 0.0 and 1.0 in relation to the most volatile component of each diagram. The fugacity coefficients for the components in the vapor phase were calculated using the Hayden and O'Connell method [J.G. Hayden, J.P. O'Connell, Ind. Eng. Chem. Process Design Develop. 14 (3) (1975) 209-216] and the activity coefficients for the liquid phase were correlated with the traditional g E models (NRTL [H. Renon, J.M. Prausnitz, Aiche J. 14 (1968) 135-144], UNIQUAC [D.S. Abrams, J.M. Prausnitz, Aiche J. 21 (1975) 116-128], and Wilson [J.M. Prausnitz, N.L. Linchtenthaler, E.G. Azevedo, Molecular Thermodynamics of Fluid-phase Equilibria, River-Prentice Hall, Upper Saddle, 1999]). The sets of parameters were then compared in order to determine which adjustments best represented the VLE.

  10. Cross sections and equilibrium fractions of deuterium ions and atoms in metal vapors. Progress report, June 1, 1978-May 31, 1979

    International Nuclear Information System (INIS)

    Morgan, T.J.

    1979-01-01

    The purpose of this program is to measure cross sections and equilibrium fractions of deuterium ions and atoms in metal vapors. In particular, in connection with double charge exchange D - ion sources, there is concern with D - formation in alkaline-earth vapor targets. Also, in connection with possible metal vapor contamination in the system, there is concern with cross sections for high energy D + , D 0 and D - collisions with these metal vapors. Results from this research will fill in a gap in knowledge of single and double charge transfer and multiple collision processes in alkaline-earth targets and provide a better understanding of D - formation mechanisms. A list of publications is included. 6 references

  11. Raman enhancement on ultra-clean graphene quantum dots produced by quasi-equilibrium plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Liu, Donghua; Chen, Xiaosong; Hu, Yibin; Sun, Tai; Song, Zhibo; Zheng, Yujie; Cao, Yongbin; Cai, Zhi; Cao, Min; Peng, Lan; Huang, Yuli; Du, Lei; Yang, Wuli; Chen, Gang; Wei, Dapeng; Wee, Andrew Thye Shen; Wei, Dacheng

    2018-01-15

    Graphene is regarded as a potential surface-enhanced Raman spectroscopy (SERS) substrate. However, the application of graphene quantum dots (GQDs) has had limited success due to material quality. Here, we develop a quasi-equilibrium plasma-enhanced chemical vapor deposition method to produce high-quality ultra-clean GQDs with sizes down to 2 nm directly on SiO 2 /Si, which are used as SERS substrates. The enhancement factor, which depends on the GQD size, is higher than conventional graphene sheets with sensitivity down to 1 × 10 -9  mol L -1 rhodamine. This is attributed to the high-quality GQDs with atomically clean surfaces and large number of edges, as well as the enhanced charge transfer between molecules and GQDs with appropriate diameters due to the existence of Van Hove singularities in the electronic density of states. This work demonstrates a sensitive SERS substrate, and is valuable for applications of GQDs in graphene-based photonics and optoelectronics.

  12. Lubrication a practical guide to lubricant selection

    CERN Document Server

    Lansdown, A R

    1982-01-01

    Lubrication: A Practical Guide to Lubricant Selection provides a guide to modern lubrication practice in industry, with emphasis on practical application, selection of lubricants, and significant factors that determine suitability of a lubricant for a specific application. Organized into 13 chapters, this book begins with a brief theoretical opening chapter on the basic principles of lubrication. A chapter then explains the choice of lubricant type, indicating how to decide whether to use oil, grease, dry lubricant, or gas lubrication. Subsequent chapters deal with detailed selection of lubric

  13. Pleural Lubrication

    Directory of Open Access Journals (Sweden)

    Cristina Porta

    2016-05-01

    Full Text Available During breathing, the pleural surfaces slide against each other continuously without damage. Pleural liquid and lubricating molecules should provide the lubrication of the sliding surfaces, thus protecting the mesothelium from shear-induced abrasion. D’Angelo et al. (Respir. Physiol. Neurobiol. 2004 measured the coefficient of kinetic friction (μ of rabbit parietal pleura sliding against visceral pleura in vitro at physiological velocities and under physiological loads; it was ~0.02 and did not change with sliding velocity, consistent with boundary lubrication. μ in boundary lubrication can be influenced by surface molecules like hyaluronan, sialomucin or surface active phospholipidis. Hyaluronan or sialomucin is able to restore good boundary lubrication in damaged mesothelium. Nevertheless, hyaluronidase and neuraminidase treatment of the mesothelium does not increase μ, though neuraminidase cleaves sialic acid from the mesothelium. Short pronase or phospholipase treatment, so as to affect only the mesothelial glycocalyx, increases μ, and this increase is removed by hyaluronan or sialomucin. On the other hand, addition of phospholipids after phospholipase treatment produces a small effect relative to that of hyaluronan or sialomucin, and this effect is similar with unsaturated or saturated phospholipids. In damaged mesothelium, the lubrication regimen becomes mixed, but addition of hyaluronan or sialomucin restores boundary lubrication.

  14. (Vapor + liquid + liquid) equilibrium measurements and correlation for {1,1,2,2-tetrafluoroethane (R134) + isobutane (R600a)} system

    International Nuclear Information System (INIS)

    Zhao, Yanxing; Gong, Maoqiong; Dong, Xueqiang; Guo, Hao; Wu, Jianfeng

    2014-01-01

    Highlights: • VLLE data for the (R134 + R600a) system at temperatures ranging from (235.311 to 241.720) K was measured. • The experiment was carried out using an apparatus based on the recirculation of vapor into liquid. • Correlation of VLE data was made using PR−HV−NRTL model. • A strong critical opalescence was observed. - Abstract: In this work, a study on the (vapor + liquid + liquid) equilibrium (VLLE) for the (R134 + R600a) system was carried out using an apparatus based on the recirculation of vapor into liquid at temperatures ranging from (235.311 to 241.720) K. The uncertainties of the composition, temperature, and pressure were less than ±0.005, ±5 mK and ±0.5 kPa, respectively. Thirty-eight experimental p–T–x data covering both branches of the binodal boundary and nineteen experimental p–T–y data were presented. Three numerical methods were used to obtain the second liquid phase compositions coexisting in equilibrium, and all the three methods lead to consistent results. Moreover, all of the experimental data were correlated by the Peng–Robinson equation of state (PR EoS) with the Huron–Vidal (HV) mixing rule involving the non-random two-liquid (NRTL) activity coefficient model. Then the vapor phase compositions were calculated. The results show good agreement with the experimental data, and the maximum deviation is less than 0.006

  15. Developments in lubricant technology

    CERN Document Server

    Srivastava, S P

    2014-01-01

    Provides a fundamental understanding of lubricants and lubricant technology including emerging lubricants such as synthetic and environmentally friendly lubricants Teaches the reader to understand the role of technology involved in the manufacture of lubricants Details both major industrial oils and automotive oils for various engines Covers emerging lubricant technology such as synthetic and environmentally friendly lubricants Discusses lubricant blending technology, storage, re-refining and condition monitoring of lubricant in equipment

  16. Determination of vapor-liquid equilibrium data and decontamination factors needed for the development of evaporator technology for use in volume reduction of radioactive waste streams

    International Nuclear Information System (INIS)

    Betts, S.E.

    1993-01-01

    A program is currently in progress at Argonne National Laboratory to evaluate and develop evaporator technology for concentrating radioactive waste streams. By concentrating radioactive waste streams, disposal costs can be significantly reduced. To effectively reduce the volume of waste, the evaporator must achieve high decontamination factors so that the distillate is sufficiently free of radioactive material. One technology that shows a great deal of potential for this application is being developed by LICON, Inc. In this program, Argonne plans to apply LICON's evaporator designs to the processing of radioactive solutions. Concepts that need to be incorporated into the design of the evaporator include, criticality safety, remote operation and maintenance, and materials of construction. To design an effective process for concentrating waste streams, both solubility and vapor-liquid equilibrium data are needed. The key issue, however, is the high decontamination factors that have been demonstrated by this equipment. Two major contributions were made to this project. First, a literature survey was completed to obtain available solubility and vapor-liquid equilibrium data. Some vapor-liquid data necessary for the project but not available in the literature was obtained experimentally. Second, the decontamination factor for the evaporator was determined using neutron activation analysis (NAA)

  17. Inhomogeneous Monte Carlo simulation of the vapor-liquid equilibrium of benzene between 300 K and 530 K

    Directory of Open Access Journals (Sweden)

    J.Janeček

    2007-09-01

    Full Text Available The inhomogeneous Monte Carlo technique is used in studying the vapor-liquid interface of benzene in a broad range of temperatures using the TraPPE potential field. The obtained values of the VLE parameters are in good agreement with the experimental values as well as with the results from GEMC simulations. In contrast to the GEMC, within one simulation box the inhomogeneous MC technique also yields information on the structural properties of the interphase between the two phases. The values of the vaporization enthalpy and the vapor pressure very well satisfy the Clausius-Clapeyron equation.

  18. Experimental measurement of vapor pressures and (vapor + liquid) equilibrium for {1,1,1,2-tetrafluoroethane (R134a) + propane (R290)} by a recirculation apparatus with view windows

    International Nuclear Information System (INIS)

    Dong Xueqiang; Gong Maoqiong; Liu Junsheng; Wu Jianfeng

    2011-01-01

    The saturated vapor pressures of 1,1,1,2-tetrafluoroethane (R134a) and propane (R290), and the (vapor + liquid) equilibrium (VLE) data at (255.000, 265.000, 275.000, and 285.000) K for the (R134a + R290) system were measured by a recirculation apparatus with view windows. The uncertainty of the temperatures, pressures, and compositions are less than ±5 mK, ±0.0005 MPa, and ±0.005, respectively. The saturated vapor pressures data were correlated by a Wagner type equation and compared with the reference data. The binary VLE data were correlated with the Peng-Robinson equation of state (PR EoS) incorporating the Huron-Vidal (HV) mixing rule utilizing the nonrandom two-liquid (NRTL) activity coefficient model. For mixtures, the maximum average absolute relative deviation of pressure is 0.15%, while the maximum average absolute deviation of vapor phase mole fraction is 0.0045. Azeotropic behavior can be found for the (R134a + R290) system at measured temperatures.

  19. Experimental measurement of vapor pressures and (vapor + liquid) equilibrium for {l_brace}1,1,1,2-tetrafluoroethane (R134a) + propane (R290){r_brace} by a recirculation apparatus with view windows

    Energy Technology Data Exchange (ETDEWEB)

    Dong Xueqiang [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Gong Maoqiong, E-mail: gongmq@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Liu Junsheng [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Wu Jianfeng, E-mail: jfwu@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China)

    2011-03-15

    The saturated vapor pressures of 1,1,1,2-tetrafluoroethane (R134a) and propane (R290), and the (vapor + liquid) equilibrium (VLE) data at (255.000, 265.000, 275.000, and 285.000) K for the (R134a + R290) system were measured by a recirculation apparatus with view windows. The uncertainty of the temperatures, pressures, and compositions are less than {+-}5 mK, {+-}0.0005 MPa, and {+-}0.005, respectively. The saturated vapor pressures data were correlated by a Wagner type equation and compared with the reference data. The binary VLE data were correlated with the Peng-Robinson equation of state (PR EoS) incorporating the Huron-Vidal (HV) mixing rule utilizing the nonrandom two-liquid (NRTL) activity coefficient model. For mixtures, the maximum average absolute relative deviation of pressure is 0.15%, while the maximum average absolute deviation of vapor phase mole fraction is 0.0045. Azeotropic behavior can be found for the (R134a + R290) system at measured temperatures.

  20. Hydrodynamic Lubrication

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 9. Hydrodynamic Lubrication Experiment with 'Floating' Drops. Jaywant H Arakeri K R Sreenivas. General Article Volume 1 Issue 9 September 1996 pp 51-58. Fulltext. Click here to view fulltext PDF. Permanent link:

  1. Solución Matricial de Modelos para Cálculo de Equilibrio Líquido-Vapor Matrix Solution of Models to Calculate Liquid-Vapor Equilibrium

    OpenAIRE

    José F Orejel-Pajarito; Raúl González-García

    2008-01-01

    El objetivo de este artículo es demostrar la viabilidad de utilizar modelos termodinámicos de coeficientes de actividad (Wilson, NRTL, UNIQUAC) programados con matrices, en lugar de estar programados con ciclos. Se determina la relación de equilibrio líquido-vapor de las mezclas Metanol-Etanol-Benceno y Acetona-Cloroformo-Metanol representados en mapas de curvas de residuo y en mapas de líneas de destilación. Para obtener resultados más confiables y conclusiones objetivas, el estudio fue apoy...

  2. Measurement and correlation of (vapor + liquid) equilibrium data for {α-pinene + p-cymene + (S)-(−)-limonene} ternary system at atmospheric pressure

    International Nuclear Information System (INIS)

    Sun, Lixia; Liao, Dankui; Yang, Zhengyu; Chen, Xiaopeng; Tong, Zhangfa

    2013-01-01

    Highlights: ► The VLE data of (α-pinene + p-cymene) and (α-pinene + p-cymene + (S)-(−)-limonene) at atmospheric pressure were measured. ► The VLE data of binary system were correlated by four activity coefficient models. ► The ternary VLE data were predicted from binary parameters of the Liebermann–Fried model. ► The constant G 123 E counters plotted on the Roozeboom diagrams. -- Abstract: (Vapor + liquid) equilibrium (VLE) data for binary system of (α-pinene + p-cymene) and ternary system of {α-pinene + p-cymene + (S)-(−)-limonene} were measured at 100.7 kPa using the modified Ellis equilibrium still. The VLE data are thermodynamically consistent. Parameters of the binary system for the four solution models — Liebermann–Fried, Wilson, NRTL, and UNIQUAC — were calculated by referencing least squares method to minimize an objective function based on the total pressure. The ternary system data were predicted with the parameters of Liebermann–Fried model obtained from the pertinent binary systems. The predicted bubble-point temperature and the vapor composition for the ternary system were in good agreement with the experimental results. Smooth representations of the results are used to construct constant excess Gibbs free energy contours on Roozeboom diagrams

  3. High accuracy calibration of a dynamic vapor sorption instrument and determination of the equilibrium humidities using single salts

    DEFF Research Database (Denmark)

    Rörig-Dalgaard, Inge; Svensson, Staffan

    2016-01-01

    We present a procedure for accurately calibrating a dynamic vapor sorption (DVS) instrument using single salts. The procedure accounts for and tailors distinct calibration tests according to the fundamental properties of each salt. Especially relevant properties influencing the calibration are th...

  4. Gibbs Ensemble Simulation on Polarizable Models: Vapor-liquid Equilibrium in Baranyai-Kiss Models of Water

    Czech Academy of Sciences Publication Activity Database

    Moučka, F.; Nezbeda, Ivo

    2013-01-01

    Roč. 360, DEC 25 (2013), s. 472-476 ISSN 0378-3812 Grant - others:GA MŠMT(CZ) LH12019 Institutional support: RVO:67985858 Keywords : multi-particle move monte carlo * Gibbs ensemble * vapor-liquid-equilibria Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.241, year: 2013

  5. A lubricant

    Energy Technology Data Exchange (ETDEWEB)

    Parfenova, V.A.; Belov, P.S.; Guliaev, I.A.; Korenev, K.D.

    1979-07-30

    For the purpose of improving the thermo-oxidation stability of washing and protective properties, dithiophosphate of the metal having the formula ((pi-R-C/sub 6/H/sub 4/OCH/sub 2/-CH/sub 2/O)/sub 2/P(=S)S)/sub 2/M (where R is the alkyl of C/sub 8/--C/sub 12/ isostructure, M is either cadmium, barium, or zinc) (I) is added into the petroleum oil for the lubrication of car engine units and containing polyethylene oxyphenylpolyamine (PEP). The lubricant has the following composition, in %: PEP, 1 to 5; (I), 0.5 to 5; petroleum oil, up to 100. In order to produce a lubricant for petroleum oil, for example MT-16, PEF and (I) are added (R = octyl or dodecyl), it is heated up to 80/sup 0/ and mixed in a nitrogen current for one hour. The combination of the additives in the patented composition has synergistic activities and the oil being patented, according to operative properties, surpasses the oil with industrial dithiophosphate additive MNI-IP-22k.

  6. (Vapor + liquid) equilibrium data for (carbon dioxide + 1,1-difluoroethane) system at temperatures from (258 to 343) K and pressures up to about 8 MPa

    International Nuclear Information System (INIS)

    Madani, Hakim; Valtz, Alain; Coquelet, Christophe; Meniai, Abdeslam Hassen; Richon, Dominique

    2008-01-01

    Accurate thermo-physical data are of utmost interest for the development of new efficient refrigeration systems. Carbon dioxide (R744) and 1,1-difluoroethane (R152a) are addressed here. Isothermal (vapor + liquid) equilibrium data are reported herein for (R744 + R152a) binary system in the (258-343) K temperature range and in the (0.14 to 7.65) MPa pressure range. A reliable 'static-analytic' method taking advantage of two online ROLSI TM micro capillary samplers is used for all thermodynamic measurements. The data are correlated using our in-house ThermoSoft thermodynamic model using the Peng-Robinson equation of state, the Mathias-Copeman alpha function, the Wong-Sandler mixing rules, and the NRTL model

  7. Modeling vapor liquid equilibrium of ionic liquids + gas binary systems at high pressure with cubic equations of state

    Directory of Open Access Journals (Sweden)

    A. C. D. Freitas

    2013-03-01

    Full Text Available Ionic liquids (IL have been described as novel environmentally benign solvents because of their remarkable characteristics. Numerous applications of these solvents continue to grow at an exponential rate. In this work, high pressure vapor liquid equilibria for 17 different IL + gas binary systems were modeled at different temperatures with Peng-Robinson (PR and Soave-Redlich-Kwong (SRK equations of state, combined with the van der Waals mixing rule with two binary interaction parameters (vdW-2. The experimental data were taken from the literature. The optimum binary interaction parameters were estimated by minimization of an objective function based on the average absolute relative deviation of liquid and vapor phases, using the modified Simplex algorithm. The solubilities of all gases studied in this work decrease as the temperature increases and increase with increasing pressure. The correlated results were highly satisfactory, with average absolute relative deviations of 2.10% and 2.25% for PR-vdW-2 and SRK-vdW-2, respectively.

  8. Solid lubricants and surfaces

    CERN Document Server

    Braithwaite, E R

    1964-01-01

    Solid Lubricants and Surfaces deals with the theory and use of solid lubricants, particularly in colloidal form. Portions of this book are devoted to graphite and molybdenum disulfides, which are widely used solid lubricants in colloidal form. An extensive literature on the laboratory examination of hundreds of solids as potential lubricants is also provided in this text. Other topics discussed include the metals and solid lubricants; techniques for examining surfaces; other solid lubricants; metal shaping; and industrial uses of solid-lubricant dispersions. This publication is beneficial to e

  9. Water adsorbate phases on ZnO and impact of vapor pressure on the equilibrium shape of nanoparticles

    Science.gov (United States)

    Kenmoe, Stephane; Biedermann, P. Ulrich

    2018-02-01

    ZnO nanoparticles are used as catalysts and have potential applications in gas-sensing and solar energy conversion. A fundamental understanding of the exposed crystal facets, their surface chemistry, and stability as a function of environmental conditions is essential for rational design and improvement of synthesis and properties. We study the stability of water adsorbate phases on the non-polar low-index (10 1 ¯ 0 ) and (11 2 ¯ 0 ) surfaces from low coverage to multilayers using ab initio thermodynamics. We show that phonon contributions and the entropies due to a 2D lattice gas at low coverage and multiple adsorbate configurations at higher coverage have an important impact on the stability range of water adsorbate phases in the (T,p) phase diagram. Based on this insight, we compute and analyze the possible growth mode of water films for pressures ranging from UHV via ambient conditions to high pressures and the impact of water adsorption on the equilibrium shape of nanoparticles in a humid environment. A 2D variant of the Wulff construction shows that the (10 1 ¯ 0 ) and (11 2 ¯ 0 ) surfaces coexist on 12-faceted prismatic ZnO nanoparticles in dry conditions, while in humid environment, the (10 1 ¯ 0 ) surface is selectively stabilized by water adsorption resulting in hexagonal prisms.

  10. 14 CFR 33.71 - Lubrication system.

    Science.gov (United States)

    2010-01-01

    ... arranged that condensed water vapor that might freeze and obstruct the line cannot accumulate at any point... fireproof. (9) Each unpressurized oil tank may not leak when subjected to a maximum operating temperature... supply becomes depleted due to failure of any part of the lubricating system other than the tank itself...

  11. Soft lubrication

    Science.gov (United States)

    Skotheim, Jan; Mahadevan, Laksminarayanan

    2004-11-01

    We study the lubrication of fluid-immersed soft interfaces and show that elastic deformation couples tangential and normal forces and thus generates lift. We consider materials that deform easily, due to either geometry (e.g a shell) or constitutive properties (e.g. a gel or a rubber), so that the effects of pressure and temperature on the fluid properties may be neglected. Four different system geometries are considered: a rigid cylinder moving tangentially to a soft layer coating a rigid substrate; a soft cylinder moving tangentially to a rigid substrate; a cylindrical shell moving tangentially to a rigid substrate; and finally a journal bearing coated with a thin soft layer, which being a conforming contact allows us to gauge the influence of contact geometry. In addition, for the particular case of a soft layer coating a rigid substrate we consider both elastic and poroelastic material responses. Finally, we consider the role of contact geometry in the context of the journal bearing, a conforming contact. For all these cases we find the same generic behavior: there is an optimal combination of geometric and material parameters that maximizes the dimensionless normal force as a function of the softness.

  12. Elasto-hydrodynamic lubrication

    CERN Document Server

    Dowson, D; Hopkins, D W

    1977-01-01

    Elasto-Hydrodynamic Lubrication deals with the mechanism of elasto-hydrodynamic lubrication, that is, the lubrication regime in operation over the small areas where machine components are in nominal point or line contact. The lubrication of rigid contacts is discussed, along with the effects of high pressure on the lubricant and bounding solids. The governing equations for the solution of elasto-hydrodynamic problems are presented.Comprised of 13 chapters, this volume begins with an overview of elasto-hydrodynamic lubrication and representation of contacts by cylinders, followed by a discussio

  13. Evaluation and Modeling of Vapor-Liquid Equilibrium and CO2 Absorption Enthalpies of Aqueous Designer Diamines for Post Combustion Capture Processes.

    Science.gov (United States)

    Luo, Weiliang; Yang, Qi; Conway, William; Puxty, Graeme; Feron, Paul; Chen, Jian

    2017-06-20

    Novel absorbents with improved characteristics are required to reduce the existing cost and environmental barriers to deployment of large scale CO 2 capture. Recently, bespoke absorbent molecules have been specifically designed for CO 2 capture applications, and their fundamental properties and suitability for CO 2 capture processes evaluated. From the study, two unique diamine molecules, 4-(2-hydroxyethylamino)piperidine (A4) and 1-(2-hydroxyethyl)-4-aminopiperidine (C4), were selected for further evaluation including thermodynamic characterization. The solubilities of CO 2 in two diamine solutions with a mass fraction of 15% and 30% were measured at different temperatures (313.15-393.15 K) and CO 2 partial pressures (up to 400 kPa) by thermostatic vapor-liquid equilibrium (VLE) stirred cell. The absorption enthalpies of reactions between diamines and CO 2 were evaluated at different temperatures (313.15 and 333.15 K) using a CPA201 reaction calorimeter. The amine protonation constants and associated protonation enthalpies were determined by potentiometric titration. The interaction of CO 2 with the diamine solutions was summarized and a simple mathematical model established that could make a preliminary but good prediction of the VLE and thermodynamic properties. Based on the analyses in this work, the two designer diamines A4 and C4 showed superior performance compared to amines typically used for CO 2 capture and further research will be completed at larger scale.

  14. An NPT Monte Carlo Molecular Simulation-Based Approach to Investigate Solid-Vapor Equilibrium: Application to Elemental Sulfur-H2S System

    KAUST Repository

    Kadoura, Ahmad Salim

    2013-06-01

    In this work, a method to estimate solid elemental sulfur solubility in pure and gas mixtures using Monte Carlo (MC) molecular simulation is proposed. This method is based on Isobaric-Isothermal (NPT) ensemble and the Widom insertion technique for the gas phase and a continuum model for the solid phase. This method avoids the difficulty of having to deal with high rejection rates that are usually encountered when simulating using Gibbs ensemble. The application of this method is tested with a system made of pure hydrogen sulfide gas (H2S) and solid elemental sulfur. However, this technique may be used for other solid-vapor systems provided the fugacity of the solid phase is known (e.g., through experimental work). Given solid fugacity at the desired pressure and temperature, the mole fraction of the solid dissolved in gas that would be in chemical equilibrium with the solid phase might be obtained. In other words a set of MC molecular simulation experiments is conducted on a single box given the pressure and temperature and for different mole fractions of the solute. The fugacity of the gas mixture is determined using the Widom insertion method and is compared with that predetermined for the solid phase until one finds the mole fraction which achieves the required fugacity. In this work, several examples of MC have been conducted and compared with experimental data. The Lennard-Jones parameters related to the sulfur molecule model (ɛ, σ) have been optimized to achieve better match with the experimental work.

  15. Measurement of (vapor + liquid) equilibrium for the systems {methanol + dimethyl carbonate} and {methanol + dimethyl carbonate + tetramethylammonium bicarbonate} at p = (34.43, 67.74) kPa

    International Nuclear Information System (INIS)

    Yang Changsheng; Zeng Hao; Yin Xia; Ma Shengyong; Sun Feizhong; Li Yafei; Li Jiao

    2012-01-01

    Highlights: ► VLE data for the binary system and the ternary system were measured. ► Methanol, dimethyl carbonate, and tetramethylammonium bicarbonate were studied. ► Isobaric experimental data were measured at p = (34.43, 67.74) kPa. ► VLE data of binary system were correlated with the Wilson, NRTL, and UNIQUAC models. ► The salt effect of TMAB on the VLE of {methanol + DMC} system was investigated. - Abstract: Isobaric (vapor + liquid) equilibrium (VLE) data for the binary system (methanol + dimethyl carbonate) and the ternary system (methanol + dimethyl carbonate + tetramethylammonium bicarbonate) have been measured at p = (34.43, 67.74) kPa using a modified Rose–Williams still. The experimental data for the binary system were well correlated by Wilson, NRTL, and UNIQUAC activity-coefficient models at the two reduced pressures. All the experimental results of the binary system passed the thermodynamic consistency test by the area test of Redlich–Kister and the point test of Van Ness et al. The experimental results of ternary system show that the salt tetramethylammonium bicarbonate has a salting-in effect on methanol. And this effect enhances when the salt concentration increases.

  16. Applications of the Simple Multi-Fluid Model to Correlations of the Vapor-Liquid Equilibrium of Refrigerant Mixtures Containing Carbon Dioxide

    Science.gov (United States)

    Akasaka, Ryo

    This study presents a simple multi-fluid model for Helmholtz energy equations of state. The model contains only three parameters, whereas rigorous multi-fluid models developed for several industrially important mixtures usually have more than 10 parameters and coefficients. Therefore, the model can be applied to mixtures where experimental data is limited. Vapor-liquid equilibrium (VLE) of the following seven mixtures have been successfully correlated with the model: CO2 + difluoromethane (R-32), CO2 + trifluoromethane (R-23), CO2 + fluoromethane (R-41), CO2 + 1,1,1,2- tetrafluoroethane (R-134a), CO2 + pentafluoroethane (R-125), CO2 + 1,1-difluoroethane (R-152a), and CO2 + dimethyl ether (DME). The best currently available equations of state for the pure refrigerants were used for the correlations. For all mixtures, average deviations in calculated bubble-point pressures from experimental values are within 2%. The simple multi-fluid model will be helpful for design and simulations of heat pumps and refrigeration systems using the mixtures as working fluid.

  17. Biodegradation of lubricant oil

    African Journals Online (AJOL)

    M

    2012-09-25

    Sep 25, 2012 ... lubricating oil, showed high biodegradation efficiency for different used lubricating oils. Capability of ..... amount after biodegradation showed no difference in the .... products polluted sites in Elele, Rivers State, Ngeria.

  18. Used lubricants and ecological problems

    International Nuclear Information System (INIS)

    Evdokimov, A.Yu.; Dzhamalov, A.A.; Lashkhi, V.L.

    1993-01-01

    This planet is undergoing a severe ecological crisis. The consequent problems include not only how to prevent the destruction of contemporary civilization, but also how to preserve mankind as a biological species. In the onset of this crisis, used lubricants (ULs) play a role that is by no means the least important. Every year, the worldwide discharge of petroleum products to the biosphere is approximately 6 million tonnes, of which more than 50% consists of ULs. The ecologically dangerous components of both commercial lubricants and used lubricants are the polycyclic aromatic hydrocarbons (PAHs) that are originally present in crude oil; polyhalobiphenyls, mainly polychlorobiphenyls (PCBs) of anthropogenic origin; sulfur- and chlorine-containing additives; a number of biocides; organic compounds of metals (lead, barium, antimony, zinc); and nitrites. These substances are distributed in the atmosphere, water, and soil, entering the food chain and appearing in foodstuffs. Moreover, hydrocarbons of petroleum and synthetic oils with a low degree of biodegradability (10-30%) accumulate in the environment and may shift the ecological equilibrium (accelerated multiplication and mutation of microorganisms that assimilate petroleum products). 32 refs., 1 fig

  19. Lubricating graphene with a nanometer-thick perfluoropolyether

    International Nuclear Information System (INIS)

    Kozbial, Andrew; Li, Zhiting; Iasella, Steven; Taylor, Alexander T.; Morganstein, Brittni; Wang, Yongjin; Sun, Jianing; Zhou, Bo; Randall, Nicholas X.; Liu, Haitao; Li, Lei

    2013-01-01

    Due to its atomic thickness (thinness), the wear of graphene in nanoscale devices or as a protective coating is a serious concern. It is highly desirable to develop effective methods to reduce the wear of graphene. In the current paper, the effect of a nano-lubricant, perfluoropolyether, on the wear of graphene on different substrates is investigated. Graphene was synthesized by chemical vapor deposition (CVD) and characterized by Raman spectroscopy. The nano-lubricant is applied on the graphene by dip-coating. The friction and wear of graphene samples are characterized by nanotribometer, AFM, optical microscopy and Raman spectroscopy. The results showed that lubricating silicon/graphene with nano-lubricant reduces the friction but increases the wear. However, lubricating nickel/graphene with nano-lubricant has little effect on the friction but reduce the wear significantly. The underlying mechanism has been discussed on the basis of the graphene–substrate adhesion and the roughness. The current study provides guidance to the future design of graphene-containing devices. - Highlights: • The effect of a nano-lubricant on the friction and wear of CVD graphene was studied. • Lubricating Graphene/Si results in lower friction but higher wear. • Lubricating Ggraphene/Ni results in lower wear but unchanged friction. • The mechanisms were discussed based on the roughness and interfacial adhesion

  20. Drag Reduction by Leidenfrost Vapor Layers

    KAUST Repository

    Vakarelski, Ivan Uriev; Marston, Jeremy O.; Chan, Derek Y. C.; Thoroddsen, Sigurdur T

    2011-01-01

    , we show that such vapor layers can reduce the hydrodynamic drag by over 85%. These results appear to approach the ultimate limit of drag reduction possible by different methods based on gas-layer lubrication and can stimulate the development

  1. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  2. Metal forming and lubrication

    DEFF Research Database (Denmark)

    Bay, Niels

    2000-01-01

    Lubrication is essential in most metal forming processes. The lubricant film has two basic functions, [1]: i. to separate the work piece and tool surfaces and ii. to cool the workpiece and the tool. Separation of the two surfaces implies lower friction facilitating deformation and lowering the tool...

  3. Lubrication method and apparatus

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, R.S.

    1988-05-03

    In a combustion turbine engine comprising a bearing member journaling a rotatable component, and compressor means providing pressurized air, the method of providing liquid lubricant to the bearing member is described comprising the steps of: providing the liquid lubricant sealed within a collapsible and penetrable bladder member; enclosing the bladder member and lubricant within a substantially closed housing sealingly cooperating with the bladder member to define a pair of chambers; arranging a penetrating lance member in one of the pair of chambers in confronting relationship with the bladder member; providing communication of the pressurized air with the other of the pair of chambers to force the bladder member into impaled sealing relationship with the lance member; communicating the lubricant to the bearing member via the lance member; and utilizing the pressurized air within the other chamber to collapse the bladder member, simultaneously flowing the lubricant to the bearing member.

  4. (Vapor + liquid) equilibrium for the binary systems {l_brace}water + glycerol{r_brace} and {l_brace}ethanol + glycerol, ethyl stearate, and ethyl palmitate{r_brace} at low pressures

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Renata; Santos, Priscilla G. dos; Mafra, Marcos R. [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil); Cardozo-Filho, Lucio [Department of Chemical Engineering, Maringa State University (UEM), Av. Colombo 5790, 87020-900 Maringa, PR (Brazil); Corazza, Marcos L., E-mail: corazza@ufpr.br [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil)

    2011-12-15

    Highlights: > We measured VLE for the binary system {l_brace}ethyl stearate and palmitate + ethanol{r_brace}. > The boiling temperatures were obtained using Othmer-type ebuliometer. > The experimental data were modeled using NRTL, UNIQUAC, and UNIFAC models. - Abstract: This work reports the experimental measurements {l_brace}(vapor + liquid) equilibrium{r_brace} for the systems {l_brace}water(1) + glycerol(2){r_brace}, {l_brace}ethanol(1) + glycerol(2){r_brace}, {l_brace}ethanol(1) + ethyl stearate(2){r_brace}, and {l_brace}ethanol(1) + ethyl palmitate(2){r_brace}. Boiling temperatures were measured using an Othmer-type ebulliometer over a pressure range of 14 kPa to 96 kPa. The experimental data were well correlated using the NRTL and UNIQUAC models. The performance of the UNIFAC-Dortmund model in relation to predicting the phase equilibrium of the systems was also studied.

  5. Practical lubrication for industrial facilities

    CERN Document Server

    Bloch, Heinz

    2016-01-01

    Now completely revised and updated, this definitive, hands-on reference provides a comprehensive resource on the fundamental principles of lubricant application, what products are available, and which lubricants are most effective for specific applications. It also offers a detailed and highly practical discussion of lubrication delivery systems. You'll gain a clearer understanding of the "why" of relevant industrial lubrication practices, and, importantly, how these practices will facilitate optimized results. Lubricant applications covered include bearings and machine elements in earthbound

  6. Equilibrium thermodynamics

    CERN Document Server

    de Oliveira, Mário J

    2017-01-01

    This textbook provides an exposition of equilibrium thermodynamics and its applications to several areas of physics with particular attention to phase transitions and critical phenomena. The applications include several areas of condensed matter physics and include also a chapter on thermochemistry. Phase transitions and critical phenomena are treated according to the modern development of the field, based on the ideas of universality and on the Widom scaling theory. For each topic, a mean-field or Landau theory is presented to describe qualitatively the phase transitions. These theories include the van der Waals theory of the liquid-vapor transition, the Hildebrand-Heitler theory of regular mixtures, the Griffiths-Landau theory for multicritical points in multicomponent systems, the Bragg-Williams theory of order-disorder in alloys, the Weiss theory of ferromagnetism, the Néel theory of antiferromagnetism, the Devonshire theory for ferroelectrics and Landau-de Gennes theory of liquid crystals. This new edit...

  7. Measurements of isothermal (vapor + liquid) phase equilibrium for {trifluoroiodomethane (R13I1) + 1,1-difluoroethane (R152a)} from T = (258.150 to 283.150) K

    International Nuclear Information System (INIS)

    Gong, Maoqiong; Cheng, Kuiwei; Dong, Xueqiang; Guo, Hao; Zhao, Yanxing; Wu, Jianfeng

    2015-01-01

    Highlights: • VLE data for (R13I1 + R152a) system were measured at four temperatures. • Experiments were based on the vapor-recirculation method. • VLE data were correlated using PR−VdWs and PR−HV−NRTL models. • Azeotropic behavior can be found. - Abstract: In this paper, isothermal (vapor + liquid) equilibrium (VLE) values for {trifluoroiodomethane (R13I1) + 1,1-difluoroethane (R152a)} at T = (258.150 to 283.150) K are presented. The experimental apparatus was based on a vapor-recirculation method. The VLE measurements were regressed by the Peng–Robinson equation of state with two models, the Van der Waals mixing rules and the Huron–Vidal mixing rules using the NRTL activity coefficient model. The newly measured VLE values satisfied the thermodynamic consistency test. The results have led to that the two models selected are both suitable for the description of the binary system. Azeotropic behavior can be found for the system measured

  8. Fuels and Lubricants Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Modern naval aircraft and turbine-powered craft require reliable and high-quality fuels and lubricants to satisfy the demands imposed upon them for top performance...

  9. Lubrication and cartilage.

    Science.gov (United States)

    Wright, V; Dowson, D

    1976-02-01

    Mechanisms of lubrication of human synovial joints have been analysed in terms of the operating conditions of the joint, the synovial fluid and articular cartilage. In the hip and knee during a walking cycle the load may rise up to four times body weight. In the knee on dropping one metre the load may go up to 25 time body weight. The elastic modulus of cartilage is similar to that of the synthetic rubber of a car tyre. The cartilage surface is rough and in elderly specimens the centre line average is 2-75 mum. The friction force generated in reciprocating tests shows that both cartilage and synovial fluid are important in lubrication. The viscosity-shear rate relationships of normal synovial fluid show that it is non-Newtonian. Osteoarthrosic fluid is less so and rheumatoid fluid is more nearly Newtonian. Experiments with hip joints in a pendulum machine show that fluid film lubrication obtains at some phases of joint action. Boundary lubrication prevails under certain conditions and has been examined with a reciprocating friction machine. Digestion of hyaluronate does not alter the boundary lubrication, but trypsin digestion does. Surface active substances (lauryl sulphate and cetyl 3-ammonium bromide) give a lubricating ability similar to that of synovial fluid. The effectiveness of the two substances varies with pH.

  10. Boundary mode lubrication of articular cartilage by recombinant human lubricin.

    Science.gov (United States)

    Gleghorn, Jason P; Jones, Aled R C; Flannery, Carl R; Bonassar, Lawrence J

    2009-06-01

    Lubrication of cartilage involves a variety of physical and chemical factors, including lubricin, a synovial glycoprotein that has been shown to be a boundary lubricant. It is unclear how lubricin boundary lubricates a wide range of bearings from tissue to artificial surfaces, and if the mechanism is the same for both soluble and bound lubricin. In the current study, experiments were conducted to investigate the hypothesis that recombinant human lubricin (rh-lubricin) lubricates cartilage in a dose-dependent manner and that soluble and bound fractions of rh-lubricin both contribute to the lubrication process. An rh-lubricin dose response was observed with maximal lubrication achieved at concentrations of rh-lubricin greater than 50 microg/mL. A concentration-response variable-slope model was fit to the data, and indicated that rh-lubricin binding to cartilage was not first order. The pattern of decrease in equilibrium friction coefficient indicated that aggregation of rh-lubricin or steric arrangement may regulate boundary lubrication. rh-lubricin localized at the cartilage surface was found to lubricate a cartilage-glass interface in boundary mode, as did soluble rh-lubricin at high concentrations (150 microg/mL); however, the most effective lubrication occurred when both soluble and bound rh-lubricin were present at the interface. These findings point to two distinct mechanisms by which rh-lubricin lubricates, one mechanism involving lubricin bound to the tissue surface and the other involving lubricin in solution. Copyright 2008 Orthopaedic Research Society

  11. Experience with synthetic fluorinated fluid lubricants

    Science.gov (United States)

    Conley, Peter L.; Bohner, John J.

    1990-01-01

    Since the late 1970's, the wet lubricant of choice for space mechanisms has been one of the family of synthetic perfluoro polyalkylether (PFPE) compounds, namely Fomblin Z-25 (Bray-815Z) or DuPont's Krytox 143xx series. While offering the advantages of extremely low vapor pressures and wide temperature ranges, these oils and derived greases have a complex chemistry compared to the more familiar natural and synthetic hydrocarbons. Many aerospace companies have conducted test programs to characterize the behavior of these compounds in a space environment, resulting in a large body of hard knowledge as well as considerable space lore concerning the suitability of the lubricants for particular applications and techniques for successful application. The facts are summarized and a few myths about the compounds are dispelled, and some performance guidelines for the mechanism design engineer are provided.

  12. Towards green lubrication in machining

    CERN Document Server

    Liew Yun Hsien, Willey

    2014-01-01

    The book gives an overview of environmental friendly gaseous and vapour, refrigerated compressed gas, solid lubricant, mist lubrication, minimum quantity lubrication (MQL) and vegetable oils that can be used as lubricants and additives in industrial machining applications. This book introduces vegetable oils as viable and good alternative resources because of their environmental friendly, non-toxic and readily biodegradable nature.  The effectiveness of various types of vegetables oils as lubricants and additives in reducing wear and friction is discussed in this book. Engineers and scientist working in the field of lubrication and machining will find this book useful.

  13. Power system with an integrated lubrication circuit

    Science.gov (United States)

    Hoff, Brian D [East Peoria, IL; Akasam, Sivaprasad [Peoria, IL; Algrain, Marcelo C [Peoria, IL; Johnson, Kris W [Washington, IL; Lane, William H [Chillicothe, IL

    2009-11-10

    A power system includes an engine having a first lubrication circuit and at least one auxiliary power unit having a second lubrication circuit. The first lubrication circuit is in fluid communication with the second lubrication circuit.

  14. Empirical model for calculating vapor-liquid equilibrium and associated phase enthalpy for the CO2--O2--Kr--Xe system for application to the KALC process

    International Nuclear Information System (INIS)

    Glass, R.W.; Gilliam, T.M.; Fowler, V.L.

    1976-01-01

    An empirical model is presented for vapor-liquid equilibria and enthalpy for the CO 2 -O 2 system. In the model, krypton and xenon in very low concentrations are combined with the CO 2 -O 2 system, thereby representing the total system of primary interest in the High-Temperature Gas-Cooled Reactor program for removing krypton from off-gas generated during the reprocessing of spent fuel. Selected properties of the individual and combined components being considered are presented in the form of tables and empirical equations

  15. Glass transitions in lubricants - Its relation to elastohydrodynamic lubrication /EHD/

    Science.gov (United States)

    Alsaad, M.; Bair, S.; Sanborn, D. M.; Winer, W. O.

    1977-01-01

    A preliminary investigation into the possible role of glass transition and glassy state behavior of lubricants in EHD contacts is reported. Measurements of the glass transition of lubricants as a function of pressure by two methods are presented along with a discussion indicating possible implications of the results to EHD lubrication.

  16. The use of stochastic method for the calculation of liquid-vapor multicomponent equilibrium and the contribution of groups theory for the evaluation of fugacity coefficient; Uso de um metodo estocastico para calculo do equilibrio liquido-vapor de sistemas multicomponentes e avaliacao de uma abordagem por contribuicao de grupos para o calculo do coeficiente de fugacidade

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcanti, Rafaelly L.; Oliveira, Jackson A. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Engenharia Quimica; Rojas, Leopoldo O.A. [Centro de Tecnologias do Gas (CTGAS), Natal, RN (Brazil)

    2008-07-01

    This work has the main objective of evaluating the mathematical model developed by Jaubert e Mutelet (2004) in terms of the prediction capacity for the calculation of the vapor-liquid equilibrium (VLE). This model is based on Peng-Robinson equation of state (EOS) and it considers the binary interaction parameters (Kij(T)) estimated by a contribution group method and dependent of the temperature. The model proposed by Jaubert e Mutelet (2004), named PPR78 (Predictive Peng-Robinson), was implemented in this work by using the Fortran language. An optimization approach based on the stochastic algorithm of Particle Swarm Optimization (PSO) was used in order to calculate the vapor-liquid equilibrium. Simulations were accomplished for several binary systems and the results were concordant with some experimental data of the investigated systems. However, for some systems different from those presented by Jaubert and Mutelet (2004), the model presented low prediction capacity. In spite of the great demand of computational performance, the algorithm PSO demonstrated robustness during the calculation of VLE and it assured convergence in most of the cases. (author)

  17. Limits of Lubrication in

    DEFF Research Database (Denmark)

    Olsson, David Dam

    as delivered stainless steel surfaces implying microstructure changes in terms of larger ratio of closed lubricant pockets due to selective grain boundary etching. Strategic surfaces have also been created by macroscopic texturing using spherical indentations having a very small edge slope in order to promote...... by strategic surfaces in comparison to normal stainless steel surfaces implying a larger extent of bi-axial stretching. Numerical simulations have been applied in order to evaluate limits of lubrication in the simulative strip reduction based on predictions of critical parameters appearing in terms......-models corresponds well to experimental results in terms of lubricant film breakdown and subsequently pick-up development. Punching and blanking have been investigated regarding tribological conditions in case of using stainless steel workpiece materials. However, this has called for development of a new test method...

  18. Thermo-Rheometric Studies of New Class Ionic Liquid Lubricants

    Science.gov (United States)

    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.

  19. Mixed Lubricated Line Contacts

    NARCIS (Netherlands)

    Faraon, I.C.

    2005-01-01

    The present work deals with friction in mixed lubricated line contacts. Components in systems are becoming smaller and due to, for instance power transmitted, partial contact may occur. In industrial applications, friction between the moving contacting surfaces cannot be avoided, therefore it is

  20. Liquid-vapor equilibrium in LaCl3-LuCl3 and PrCl3-NdCl3 systems

    International Nuclear Information System (INIS)

    Nisel'son, L.A.; Lyzlov, Yu.N.; Solov'ev, S.I.

    1978-01-01

    The liquid-vapour equilibrium in the systems LaCl 3 -LuCl 3 and PrCl 3 -NdCl 3 was studied by the boiling-point method. It was established that the system LaCl 3 -LuCl 3 is near-ideal. In the PrCl 3 -NdCl 3 system, a considerable positive deviation from the ideal with the formation of an azeotrope was detected. The azeotrope has a ''smeared-out'' minimum, which falls on a mixture containing approximately 65 mol.% neodymium trichloride. The boiling point of this mixture at a pressure of 1 mm Hg is approximately 975 deg C. The relative volatility coefficients in both systems were studied by the Raleigh distillation method. The presence of the azeotrope in the system PrCl 3 -NdCl 3 is confirmed by the nature of the dependence of the relative volatility coefficient on the composition of the mixture

  1. Drag Reduction by Leidenfrost Vapor Layers

    KAUST Repository

    Vakarelski, Ivan Uriev

    2011-05-23

    We demonstrate and quantify a highly effective drag reduction technique that exploits the Leidenfrost effect to create a continuous and robust lubricating vapor layer on the surface of a heated solid sphere moving in a liquid. Using high-speed video, we show that such vapor layers can reduce the hydrodynamic drag by over 85%. These results appear to approach the ultimate limit of drag reduction possible by different methods based on gas-layer lubrication and can stimulate the development of related energy saving technologies.

  2. A preventive maintenance lubricant

    Energy Technology Data Exchange (ETDEWEB)

    Chapaykina, S A; Ol' kov, P L; Pertsev, A N; Rodzevillo, I T; Rogacheva, O I; Zinov' yev, A P

    1980-02-15

    A method is disclosed to lower the adherence of materials by reducing the viscosity of a preventive maintenance lubricant against adhesion of moist, freeflowing materials, containing extract of selective cleaning of oil fractions and asphalt. Gas oil of catalytic cracking is added having a boiling point of 190-300 degrees, with the following ratio of components (%): selective cleaning extract, 43-50; asphalt, 14-16; and gas oil of catalytic cracking, the remainder, Treating a surface with the proposed lubricant lowers the specific resistance to shift of rock compared with the prototype (g/cm/sup 2/): sand (moisture content, 18%) from 3.82 to 1.55; and clay (moisture content 16%), from 5.41 to 3.51.

  3. Turbine lubrication fluid varnish mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Farooq, Khalid [Pall Corporation, Port Washington, NY (United States)

    2010-04-15

    Varnish deposits on internal surfaces in turbine lube systems result in a number of adverse operational issues, especially the restriction and sticking of the moving parts of servo- or directional control valves, resulting in their malfunction. The lubrication fluid has limited solvency for the varnish-forming material, hence a typical turbine will have the majority of this material as deposits and a relatively small portion as suspension in the fluid phase, in quasi-equilibrium with the deposits. The lube system needs to be cleaned by removing the suspended varnish-forming material from the fluid phase, which allows the deposits to re-entrain into the fluid phase, until the majority of the transferable deposits are removed and the fluid carries no significant amount of the material to have any adverse effect. The methods used for the removal of varnish from turbine lube systems include chemical cleaning/flushing, electrostatic charge induced agglomeration/retention, and the adsorption of the varnish suspended in the oil on an adsorbent medium. The paper discusses an absorption-based removal method that utilizes a fibrous medium that has pronounced affinity for the removal and retention of the varnish-forming material from the fluid as well as the deposits from surfaces that are in quasi-equilibrium with the varnish precursors in the fluid. The filtration medium is a composite, made with cellulose bonded by specially formulated, temperature-cured resins. The absorptive medium exhibits high structural and chemical integrity and has been thoroughly tested on operating turbines, showing reduction in varnish levels from the critical range to below normal range in a relatively short time. The experience with the utilization of the absorptive medium in laboratory tests and in two operating turbines is presented. (orig.)

  4. Fault lubrication during earthquakes.

    Science.gov (United States)

    Di Toro, G; Han, R; Hirose, T; De Paola, N; Nielsen, S; Mizoguchi, K; Ferri, F; Cocco, M; Shimamoto, T

    2011-03-24

    The determination of rock friction at seismic slip rates (about 1 m s(-1)) is of paramount importance in earthquake mechanics, as fault friction controls the stress drop, the mechanical work and the frictional heat generated during slip. Given the difficulty in determining friction by seismological methods, elucidating constraints are derived from experimental studies. Here we review a large set of published and unpublished experiments (∼300) performed in rotary shear apparatus at slip rates of 0.1-2.6 m s(-1). The experiments indicate a significant decrease in friction (of up to one order of magnitude), which we term fault lubrication, both for cohesive (silicate-built, quartz-built and carbonate-built) rocks and non-cohesive rocks (clay-rich, anhydrite, gypsum and dolomite gouges) typical of crustal seismogenic sources. The available mechanical work and the associated temperature rise in the slipping zone trigger a number of physicochemical processes (gelification, decarbonation and dehydration reactions, melting and so on) whose products are responsible for fault lubrication. The similarity between (1) experimental and natural fault products and (2) mechanical work measures resulting from these laboratory experiments and seismological estimates suggests that it is reasonable to extrapolate experimental data to conditions typical of earthquake nucleation depths (7-15 km). It seems that faults are lubricated during earthquakes, irrespective of the fault rock composition and of the specific weakening mechanism involved.

  5. Design considerations in mechanical face seals for improved performance. 2: Lubrication

    Science.gov (United States)

    Ludwig, L. P.; Greiner, H. F.

    1977-01-01

    The importance of sealing technology in our industrial, chemical-oriented society in regard to maintenance and environmental contamination is pointed out. It is stated that seal performance (leakage, life) is directly related to seal lubrication. Current thinking in regard to seal lubrication is reviewed; the effect of energy dissipation in the thin lubricating film separating the sealing faces is pointed out, and the results of vaporization due to heating are illustrated. Also, hydrodynamic lubrication is reviewed, and an inherent tendency for the seal to operate with angular misalignment is shown. Recent work on hydrostatic effects is summarized and the conditions for seal instability are discussed. Four different modes of seal lubrication are postulated with the mode type being a strong function of speed and pressure.

  6. Design considerations in mechanical face seals for improved performance. II - Lubrication

    Science.gov (United States)

    Ludwig, L. P.; Greiner, H. F.

    1977-01-01

    The importance of sealing technology in the U.S. industrial chemical-orientated society in regard to maintenance and environmental contamination is pointed out. It is stated that seal performance (leakage, life) is directly related to seal lubrication, which is a mechanism not well understood. Current thinking in regard to seal lubrication is reviewed, the effect of energy dissipation in the thin lubricating film separating the sealing faces is pointed out, and the results of vaporization due to heating are illustrated. Also, hydrodynamic lubrication is reviewed, and an inherent tendency for the seal to operate with angular misalignment is pointed out. Recent work on hydrostatic effects is summarized and the conditions for seal instability are discussed. Four different modes of seal lubrication are postulated with the mode type being a strong function of speed and pressure.

  7. Cooling lubricants; Kuehlschmierstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, W. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Breuer, D. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Blome, H. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Deininger, C. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Hahn, J.U. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Kleine, H. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Nies, E. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Pflaumbaum, W. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Stockmann, R. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Willert, G. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Sonnenschein, G. [Maschinenbau- und Metall-Berufsgenossenschaft, Duesseldorf (Germany)

    1996-08-01

    As a rule, the base substances used are certain liquid hydrocarbons from mineral oils as well as from native and synthetic oils. Through the addition of further substances the cooling lubricant takes on the particular qualities required for the use in question. Employees working with cooling lubricants are exposed to various hazards. The assessment of the concentrations at the work station is carried out on the basis of existing technical rules for contact with hazardous substances. However, the application/implementation of compulsory investigation and supervision in accordance with these rules is made difficult by the fact that cooling lubricants are, as a rule, made up of complicated compound mixtures. In addition to protecting employees from exposure to mists and vapours from the cooling lubricants, protection for the skin is also of particular importance. Cooling lubricants should not, if at all possible, be brought into contact with the skin. Cleansing the skin and skin care is just as important as changing working clothes regularly, and hygiene and cleanliness at the workplace. Unavoidable emissions are to be immediately collected at the point where they arise or are released and safely disposed of. This means taking into account all sources of emissions. The programme presented in this report therefore gives a very detailed account of the individual protective measures and provides recommendations for the design of technical protection facilities. (orig./MG) [Deutsch] Als Basisstoffe dienen in der Regel bestimmte fluessige Kohlenwasserstoffverbindungen aus Mineraloelen sowie aus nativen oder synthetischen Oelen. Durch die Zugabe von weiteren Stoffen erlangt der Kuehlschmierstoff seine fuer den jeweiligen Anwendungsabfall geforderten Eigenschaften. Beschaeftigte, die mit Kuehlschmierstoffen umgehen, sind unterschiedliche Gefahren ausgesetzt. Die Beurteilung der Kuehlschmierstoffkonzentrationen in der Luft am Arbeitsplatz erfolgt auf der Grundlage bestehender

  8. Self lubricating fluid bearings

    International Nuclear Information System (INIS)

    Kapich, D.D.

    1980-01-01

    The invention concerns self lubricating fluid bearings, which are used in a shaft sealed system extending two regions. These regions contain fluids, which have to be isolated. A first seal is fluid tight for the first region between the carter shaft and the shaft. The second seal is fluid tight between the carter and the shaft, it communicates with the second region. The first fluid region is the environment surrounding the shaft carter. The second fluid region is a part of a nuclear reactor which contains the cooling fluid. The shaft is conceived to drive a reactor circulating and cooling fluid [fr

  9. Self-lubricating formula

    Energy Technology Data Exchange (ETDEWEB)

    Borzenko, V.A.; Koltovskiy, L.V.; Koshelyov, Yu.I.; Kuzovlyev, G.F.; Lebedyev, S.I.; Sitnikov, S.A.; Telegin, V.D.

    1979-12-30

    To improve operation of scrubbers that operate in crystallizers for deparaffinization of oil products, a formula is being suggested which contains siliceous fibers, and a type of thermoactive resin - phenol-formaldehyde laquer, with the following component ration (% weight): carbon fiber 20-25, siliceous fibers 20-30, dry lubricant 10-15, phenolformaldehyde laquer up to 100. Phys.-mech. characteristics are flexure, compression, Ak of the suggested and known compositions (kgs/cm/sup 2/) 2150-2450 and 2550-2700, 32-37 and 1750, 2150 and 27 operation resource 2100:2500 and 1400.

  10. Synthetic lubricating oils

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Jurado, J

    1953-01-01

    A yellow solid petroleum paraffin d/sup 60/ 0.808, I number 3.5, average molecular weight 350, chlorinated and condensed with benzene, xylene, or naphthalene by the Friedel and Crafts reaction, in the presence of anhydrous AlCl/sub 3/ or activated Al, gave synthetic lubricating oils. Xylene was the preferred aromatic compound, naphthalene required the use of less completely chlorinated paraffin, benzene produced resins difficult to remove and gave darker oils with excessive green fluorescence. Activated Al rather than anhydrous AlCl/sub 3/ gave darker oils with higher viscosity and Conradson C values. Tar from the low-temperature distillation of lignite, used as a source of a paraffin fraction melting 40/sup 0/ to 48/sup 0/ (chlorinated to 26.5 percent Cl) and an aromatic fraction, 45 percent aromatic compounds by volume (mainly polysubstituted benzenes), I number 10, was converted to a similar synthetic lubricant with the following properties: Kinematic viscosity at 210/sup 0/ F., 50.4 centistokes; viscosity index, 92; Conradson C, 1.5 percent; solidification point, 9/sup 0/; S, 0.41 percent.

  11. Vapor-liquid equilibrium data for five binary systems of methanol, tert-butylalcohol, tert-butylmethylether and water, and quaternary reactive system producing tert-butylmethylether from methanol and tert-butylalcohol; Metanoru, tert-buchiruarukoru, tert-buchirumechirueteru oyobi mizu wo kumiawaseta 5shu no niseibunkei to metanoru to tert-buchiruarukoru ni yoru eteruka hannokei no taikiatsuka ni okeru kieki heiko deta

    Energy Technology Data Exchange (ETDEWEB)

    Komatsu, H.; Nakamura, M.; Yamashita, Y.; Hirai, C. [Toyohashi Univ. of Technology (Japan)

    1997-11-01

    At atmospheric pressure, vapor-liquid equilibrium relationships for five binary systems of methanol-tert-butylalcohol, methanol-tert-butylmethylether, tert-butylalcohol-tert-butylmethylether, water-tert-butylalcohol and water-tert-butylmethylether are observed. The Wilson parameters for the binary systems have been obtained. Comparisons between the Wilson method, The ASOG method and the UNIFAC method are made. Vapor-liquid equilibrium relationships of the quaternary reactive system producing tert-butylmethylether by use of methanol and tert-butylalcohol are also observed, and it is confirmed that the Wilson parameters resulting from the data of binary systems can be used to estimate the vapor-liquid equilibrium data for the quaternary reactive system of methanol-tert-butylalcohol-tert-butylmethylether-water. 6 refs., 7 figs., 5 tabs.

  12. Equilibrium and non equilibrium in fragmentation

    International Nuclear Information System (INIS)

    Dorso, C.O.; Chernomoretz, A.; Lopez, J.A.

    2001-01-01

    Full text: In this communication we present recent results regarding the interplay of equilibrium and non equilibrium in the process of fragmentation of excited finite Lennard Jones drops. Because the general features of such a potential resemble the ones of the nuclear interaction (fact that is reinforced by the similarity between the EOS of both systems) these studies are not only relevant from a fundamental point of view but also shed light on the problem of nuclear multifragmentation. We focus on the microscopic analysis of the state of the fragmenting system at fragmentation time. We show that the Caloric Curve (i e. the functional relationship between the temperature of the system and the excitation energy) is of the type rise plateau with no vapor branch. The usual rise plateau rise pattern is only recovered when equilibrium is artificially imposed. This result puts a serious question on the validity of the freeze out hypothesis. This feature is independent of the dimensionality or excitation mechanism. Moreover we explore the behavior of magnitudes which can help us determine the degree of the assumed phase transition. It is found that no clear cut criteria is presently available. (Author)

  13. Oleoplaning droplets on lubricated surfaces

    Science.gov (United States)

    Daniel, Dan; Timonen, Jaakko V. I.; Li, Ruoping; Velling, Seneca J.; Aizenberg, Joanna

    2017-10-01

    Recently, there has been much interest in using lubricated surfaces to achieve extreme liquid repellency: a foreign droplet immiscible with the underlying lubricant layer was shown to slide off at a small tilt angle behaviour was hypothesized to arise from a thin lubricant overlayer film sandwiched between the droplet and solid substrate, but this has not been observed experimentally. Here, using thin-film interference, we are able to visualize the intercalated film under both static and dynamic conditions. We further demonstrate that for a moving droplet, the film thickness follows the Landau-Levich-Derjaguin law. The droplet is therefore oleoplaning--akin to tyres hydroplaning on a wet road--with minimal dissipative force and no contact line pinning. The techniques and insights presented in this study will inform future work on the fundamentals of wetting for lubricated surfaces and enable their rational design.

  14. High-Performing, Low-Temperature-Operating, Long-Lifetime Aerospace Lubricants

    Science.gov (United States)

    Joshi, Prakash

    2015-01-01

    Long-duration space exploration will require spacecraft systems that can operate effectively over several years with minimal or no maintenance. Aerospace lubricants are key components of spacecraft systems. Physical Sciences Inc., has synthesized and characterized novel ionic liquids for use in aerospace lubricants that contribute to decreased viscosity, friction, and wear in aerospace systems. The resulting formulations offer low vapor pressure and outgassing properties and thermal stability up to 250 C. They are effective for use at temperatures as low as -70 C and provide long-term operational stability in aerospace systems. In Phase II, the company scaled several new ionic liquids and evaluated a novel formulation in a NASA testbed. The resulting lubricant compounds will offer lower volatility, decreased corrosion, and better tribological characteristics than standard liquid lubricants, particularly at lower temperatures.

  15. Tribochemical synthesis of nano-lubricant films from adsorbed molecules at sliding solid interface: Tribo-polymers from α-pinene, pinane, and n-decane

    Science.gov (United States)

    He, Xin; Barthel, Anthony J.; Kim, Seong H.

    2016-06-01

    The mechanochemical reactions of adsorbed molecules at sliding interfaces were studied for α-pinene (C10H16), pinane (C10H18), and n-decane (C10H22) on a stainless steel substrate surface. During vapor phase lubrication, molecules adsorbed at the sliding interface could be activated by mechanical shear. Under the equilibrium adsorption condition of these molecules, the friction coefficient of sliding steel surfaces was about 0.2 and a polymeric film was tribochemically produced. The synthesis yield of α-pinene tribo-polymers was about twice as much as pinane tribo-polymers. In contrast to these strained bicyclic hydrocarbons, n-decane showed much weaker activity for tribo-polymerization at the same mechanical shear condition. These results suggested that the mechanical shear at tribological interfaces could induce the opening of the strained ring structure of α-pinene and pinane, which leads to polymerization of adsorbed molecules at the sliding track. On a stainless steel surface, such polymerization reactions of adsorbed molecules do not occur under typical surface reaction conditions. The mechanical properties and boundary lubrication efficiency of the produced tribo-polymer films are discussed.

  16. Para-equilibrium phase diagrams

    International Nuclear Information System (INIS)

    Pelton, Arthur D.; Koukkari, Pertti; Pajarre, Risto; Eriksson, Gunnar

    2014-01-01

    Highlights: • A rapidly cooled system may attain a state of para-equilibrium. • In this state rapidly diffusing elements reach equilibrium but others are immobile. • Application of the Phase Rule to para-equilibrium phase diagrams is discussed. • A general algorithm to calculate para-equilibrium phase diagrams is described. - Abstract: If an initially homogeneous system at high temperature is rapidly cooled, a temporary para-equilibrium state may result in which rapidly diffusing elements have reached equilibrium but more slowly diffusing elements have remained essentially immobile. The best known example occurs when homogeneous austenite is quenched. A para-equilibrium phase assemblage may be calculated thermodynamically by Gibbs free energy minimization under the constraint that the ratios of the slowly diffusing elements are the same in all phases. Several examples of calculated para-equilibrium phase diagram sections are presented and the application of the Phase Rule is discussed. Although the rules governing the geometry of these diagrams may appear at first to be somewhat different from those for full equilibrium phase diagrams, it is shown that in fact they obey exactly the same rules with the following provision. Since the molar ratios of non-diffusing elements are the same in all phases at para-equilibrium, these ratios act, as far as the geometry of the diagram is concerned, like “potential” variables (such as T, pressure or chemical potentials) rather than like “normal” composition variables which need not be the same in all phases. A general algorithm to calculate para-equilibrium phase diagrams is presented. In the limit, if a para-equilibrium calculation is performed under the constraint that no elements diffuse, then the resultant phase diagram shows the single phase with the minimum Gibbs free energy at any point on the diagram; such calculations are of interest in physical vapor deposition when deposition is so rapid that phase

  17. Ionic Liquids as Novel Lubricants and /or Lubricant Additives

    Energy Technology Data Exchange (ETDEWEB)

    Qu, J. [ORNL; Viola, M. B. [General Motors Company

    2013-10-31

    This ORNL-GM CRADA developed ionic liquids (ILs) as novel lubricants or oil additives for engine lubrication. A new group of oil-miscible ILs have been designed and synthesized with high thermal stability, non-corrosiveness, excellent wettability, and most importantly effective anti-scuffing/anti-wear and friction reduction characteristics. Mechanistic analysis attributes the superior lubricating performance of IL additives to their physical and chemical interactions with metallic surfaces. Working with a leading lubricant formulation company, the team has successfully developed a prototype low-viscosity engine oil using a phosphonium-phosphate IL as an anti-wear additive. Tribological bench tests of the IL-additized formulated oil showed 20-33% lower friction in mixed and elastohydrodynamic lubrication and 38-92% lower wear in boundary lubrication when compared with commercial Mobil 1 and Mobil Clean 5W-30 engine oils. High-temperature, high load (HTHL) full-size engine tests confirmed the excellent anti-wear performance for the IL-additized engine oil. Sequence VID engine dynamometer tests demonstrated an improved fuel economy by >2% for this IL-additized engine oil benchmarked against the Mobil 1 5W-30 oil. In addition, accelerated catalyst aging tests suggest that the IL additive may potentially have less adverse impact on three-way catalysts compared to the conventional ZDDP. Follow-on research is needed for further development and optimization of IL chemistry and oil formulation to fully meet ILSAC GF-5 specifications and further enhance the automotive engine efficiency and durability.

  18. Top-of-Rail lubricant

    Energy Technology Data Exchange (ETDEWEB)

    Alzoubi, M. F.; Fenske, G. R.; Erck, R. A.; Boparai, A. S.

    2000-07-14

    Analysis of the volatile and semivolatile fractions collected after use of the TOR lubricant indicated that other than contaminants in the collection laboratory, no compounds on the EPA's Target Compound Lists (Tables 2 and 5) were detected in these fractions. The data of these qualitative analyses, given in the various tables in the text, indicate only the relative amounts of the tentatively identified compounds. The authors recommend that quantitative analysis be performed on the volatile and semivolatile fractions to allow confirmation of the tentatively identified compounds and to obtain absolute amounts of the detected compounds. Additionally, the semivolatile fraction should be analyzed by liquid chromatography/mass spectrometry to identify compounds that are not chromatographable under the temperature program used for determination of semivolatile compounds. Introducing the top-of-rail (TOR) lubricant into the wheel/rail interface results in a reduction of almost 60% of lateral friction force over the forces encountered under dry conditions. This reveals good potential for energy savings, as well as wear reduction, for railroad companies. In TOR lubrication, an increase in the angle of attack and axle load results in increased lateral friction and rate of lubricant consumption. The most efficient TOR lubricant quantity to be used in the wheel/rail interface must be calculated precisely according to the number of cars, axle loads, train speed, and angle of attack.

  19. Development of lubricant test for punching and blanking

    DEFF Research Database (Denmark)

    Olsson, David Dam

    2001-01-01

    The background for development of new lubricants Requirements to lubricant test for punching Methods of evaluating lubricants Test equipment developed at DTU Conclusion.......The background for development of new lubricants Requirements to lubricant test for punching Methods of evaluating lubricants Test equipment developed at DTU Conclusion....

  20. Tethered Lubricants for Small Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lynden A. Archer

    2006-01-09

    The objective of this research project is two-fold. First, to fundamentally understand friction and relaxation dynamics of polymer chains near surfaces; and second, to develop novel self-lubricated substrates suitable for MEMS devices. During the three-year performance period of this study the PI and his students have shown using theory and experiments that systematic introduction of disorder into tethered lubricant coatings (e.g. by using self-assembled monolayer (SAM) mixtures or SAMs with nonlinear, branched architectures) can be used to significantly reduce the friction coefficient of a surface. They have also developed a simple procedure based on dielectric spectroscopy for quantifying the effect of surface disorder on molecular relaxation in lubricant coatings. Details of research accomplishments in each area of the project are described in the body of the report.

  1. Numerical analysis of all flow state lubrication performance of water-lubricated thrust bearing

    International Nuclear Information System (INIS)

    Deng Xiao; Deng Liping; Huang Wei; Liu Lizhi; Zhao Xuecen; Liu Songya

    2015-01-01

    A model enabling all different flow state lubrication performance simulation and analysis for water-lubricated thrust bearing is presented, considering the temperature influence and elastic deformation. Lubrication state in the model is changed directly from laminar lubrication to turbulent lubrication once Reynolds number exceeds the critical Reynolds number. The model is numerically solved and results show that temperature variation is too little to influence the lubrication performance; the elastic deformation can slightly reduce the load carrying capacity of the thrust bearing; and the turbulent lubrication can remarkably improve the load carrying capacity. (authors)

  2. REFRIGERANT/LUBRICANT MIXTURES: PROBLEMS OF APPLICATION AND PROPERTY RESEARCH

    Directory of Open Access Journals (Sweden)

    Yu. Semenyuk

    2013-10-01

    Full Text Available The results and generalizations of thermophysical property research for the refrigerant/lubricant mixtures are summarized. The methodological aspects of the experimental studies of the thermal properties of real working media for vapor compression refrigeration machines and the general principles of the thermodynamic properties simulation for such solutions are analyzed. It is shown that the admixtures of compressor oil in the refrigerant make the efficiency parameters of compressor systems much lower. The question of a selective solubility of the multicomponent refrigerants in compressor oils is discussed.

  3. Laboratory services series: a lubrication program

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, H.B.; Miller, T.L.

    1976-05-01

    The diversity of equipment and operating conditions at a major national research and development laboratory requires a systematic, effective lubrication program. The various phases of this program and the techniques employed in formulating and administering this program are discussed under the following topics: Equipment Identification, Lubrication Requirements, Assortment of Lubricants, Personnel, and Scheduling.

  4. Laboratory services series: a lubrication program

    International Nuclear Information System (INIS)

    Bowen, H.B.; Miller, T.L.

    1976-05-01

    The diversity of equipment and operating conditions at a major national research and development laboratory requires a systematic, effective lubrication program. The various phases of this program and the techniques employed in formulating and administering this program are discussed under the following topics: Equipment Identification, Lubrication Requirements, Assortment of Lubricants, Personnel, and Scheduling

  5. A new lubricant carrier for metal forming

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Bay, Niels; Tang, Peter Torben

    2009-01-01

    A lubricant carrier for metal forming processes is developed. Surfaces with pores of micrometer size for entrapping lubricant are generated by electrochemical deposition of an alloy, consisting of two immiscible metals, of which one metal subsequently is etched away leaving 5 mu m layers with a s...... extrusion at high reduction and excessive stroke comparing with conventionally lubrication using phosphate coating and soap....

  6. Solid lubricants in the power station

    International Nuclear Information System (INIS)

    Gaensheimer, J.

    1981-01-01

    Example application are first outlined, followed by descriptions of inorganic solid lubricants and plastics. Waxes, soaps and salts are discussed. Notes for usage are given. Solid lubricants in oils and greases are comprehensively described, followed by the sections entitled Solid lubricants for gearboxes . References to samples, tests, standards and bibliography make up the conclusion. (orig.) [de

  7. 21 CFR 880.6375 - Patient lubricant.

    Science.gov (United States)

    2010-04-01

    ... § 880.6375 Patient lubricant. (a) Identification. A patient lubricant is a device intended for medical... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Patient lubricant. 880.6375 Section 880.6375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL...

  8. Tribological Properties of a Pennzane(Registered Trademark)-Based Liquid Lubricant (Disubstituted Alkylated Cyclopentane) for Low Temperature Space Applications

    Science.gov (United States)

    Venier, Clifford; Casserly, Edward W.; Jones, William R., Jr.; Marchetti, Mario; Jansen, Mark J.; Predmore, Roamer E.

    2002-01-01

    The tribological properties of a disubstituted alkylated cyclopentane, Pennzane (registered) Synthesized Hydrocarbon Fluid X-1000, are presented. This compound is a lower molecular weight version of the commonly used multiply alkylated cyclopentane, Pennzane X-2000, currently used in many space mechanisms. New, lower temperature applications will require liquid lubricants with lower viscosities and pour points and acceptable vapor pressures. Properties reported include: friction and wear studies and lubricated lifetime in vacuum; additionally, typical physical properties (i.e., viscosity-temperature, pour point, flash and fire point, specific gravity, refractive index, thermal properties, volatility and vapor pressure) are reported.

  9. Vapor Pressures of Several Commercially Used Alkanolamines

    NARCIS (Netherlands)

    Klepacova, Katarina; Huttenhuis, Patrick J. G.; Derks, Peter W. J.; Versteeg, Geert F.; Klepáčová, Katarína

    For the design of acid gas treating processes, vapor-liquid equilibrium (VLE) data must be available of the solvents to be applied. In this study the vapor pressures of seven frequently industrially used alkanolamines (diethanolamine, N-methylethanolamine, N,N-dimethylethanolamine,

  10. Local equilibrium

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1984-12-15

    From 3-6 September the First International Workshop on Local Equilibrium in Strong Interaction Physics took place in Bad-Honnef at the Physics Centre of the German Physical Society. A number of talks covered the experimental and theoretical investigation of the 'hotspots' effect, both in high energy particle physics and in intermediate energy nuclear physics.

  11. Equilibrium Dialysis

    African Journals Online (AJOL)

    context of antimicrobial therapy in malnutrition. Dialysis has in the past presented technical problems, being complicated and time-consuming. A new dialysis system based on the equilibrium technique has now become available, and it is the principles and practical application of this apparatus (Kontron Diapack; Kontron.

  12. Strategic Equilibrium

    NARCIS (Netherlands)

    van Damme, E.E.C.

    2000-01-01

    An outcome in a noncooperative game is said to be self-enforcing, or a strategic equilibrium, if, whenever it is recommended to the players, no player has an incentive to deviate from it.This paper gives an overview of the concepts that have been proposed as formalizations of this requirement and of

  13. Maximin equilibrium

    NARCIS (Netherlands)

    Ismail, M.S.

    2014-01-01

    We introduce a new concept which extends von Neumann and Morgenstern's maximin strategy solution by incorporating `individual rationality' of the players. Maximin equilibrium, extending Nash's value approach, is based on the evaluation of the strategic uncertainty of the whole game. We show that

  14. A Review to the Laser Cladding of Self-Lubricating Composite Coatings

    Science.gov (United States)

    Quazi, M. M.; Fazal, M. A.; Haseeb, A. S. M. A.; Yusof, Farazila; Masjuki, H. H.; Arslan, A.

    2016-06-01

    Liquid lubricants are extremely viable in reducing wear damage and friction of mating components. However, due to the relentless pressure and the recent trend towards higher operating environments in advanced automotive and aerospace turbo-machineries, these lubricants cease to perform and hence, an alternate system is required for maintaining the self-lubricating environment. From the viewpoint of tribologist, wear is related to near-surface regions and hence, surface coatings are considered suitable for improving the functioning of tribo-pairs. Wear resistant coatings can be fabricated with the addition of various solid lubricants so as to reduce friction drag. In order to protect bulk substrates, self-lubricating wear resistant composite coatings have been fabricated by employing various surface coating techniques such as electrochemical process, physical and chemical vapor depositions, thermal and plasma spraying, laser cladding etc. Studies related to laser-based surface engineering approaches have remained vibrant and are recognized in altering the near surface regions. In this work, the latest developments in laser based self-lubricating composite coatings are highlighted. Furthermore, the effect of additives, laser processing parameters and their corresponding influence on mechanical and tribological performance is briefly reviewed.

  15. Green Lubricants for Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels

    2010-01-01

    The increasing focus on legislation towards diminishing the impact on working environment as well as external environment has driven efforts to develop new, environmentally benign lubricants for metal forming. The present paper gives an overview of these efforts to substitute environmentally...

  16. Self lubrication of bitumen froth in pipelines

    International Nuclear Information System (INIS)

    Joseph, D.D.

    1997-01-01

    In this paper I will review the main properties of water lubricated pipelines and explain some new features which have emerged from studies of self-lubrication of Syncrudes' bitumen froth. When heavy oils are lubricated with water, the water and oil are continuously injected into a pipeline and the water is stable when in a lubricating sheath around the oil core. In the case of bitumen froth obtained from the Alberta tar sands, the water is dispersed in the bitumen and it is liberated at the wall under shear; water injection is not necessary because the froth is self-lubricating

  17. Sweatshop equilibrium

    OpenAIRE

    Chau, Nancy H.

    2009-01-01

    This paper presents a capability-augmented model of on the job search, in which sweatshop conditions stifle the capability of the working poor to search for a job while on the job. The augmented setting unveils a sweatshop equilibrium in an otherwise archetypal Burdett-Mortensen economy, and reconciles a number of oft noted yet perplexing features of sweatshop economies. We demonstrate existence of multiple rational expectation equilibria, graduation pathways out of sweatshops in complete abs...

  18. Vaporization of irradiated droplets

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  19. De-Lubrication Behavior Of Novel EBS Based Admixed Lubricant In Aluminum P/M Alloy

    Directory of Open Access Journals (Sweden)

    Oh M.C.

    2015-06-01

    Full Text Available The objective of the present research is to develop a novel lubricant for Al-Cu-Mg P/M alloy and to address the effects of the lubricant and compaction pressure on sintered properties. A lubricant mixture consisting of Ethylene Bis Stearamide, Zn-Stearate, and fatty acid was newly developed in this study, and the de-lubrication behavior was compared with that of other commercial lubricants, such as Ethylene Bis Stearamide, Zn-Stearate, and Al-Stearate. Density and transverse rupture strength of sintered materials with each lubricant were examined, respectively. The microstructural analysis was conducted using optical microscope.

  20. Identifying lubricant options for compressor bearing designs

    Science.gov (United States)

    Karnaz, J.; Seeton, C.; Dixon, L.

    2017-08-01

    Today’s refrigeration and air conditioning market is not only driven by the environmental aspects of the refrigerants, but also by the energy efficiency and reliability of system operation. Numerous types of compressor designs are used in refrigeration and air conditioning applications which means that different bearings are used; and in some cases, multiple bearing types within a single compressor. Since only one lubricant is used, it is important to try to optimize the lubricant to meet the various demands and requirements for operation. This optimization entails investigating different types of lubricant chemistries, viscosities, and various formulation options. What makes evaluating these options more challenging is the refrigerant which changes the properties of the lubricant delivered to the bearing. Once the lubricant and refrigerant interaction are understood, through various test methods, then work can start on collaborating with compressor engineers on identifying the lubricant chemistry and formulation options. These interaction properties are important to the design engineer to make decisions on the adequacy of the lubricant before compressor tests are started. This paper will discuss the process to evaluate lubricants for various types of compressors and bearing design with focus on what’s needed for current refrigerant trends. In addition, the paper will show how the lubricant chemistry choice can be manipulated through understanding of the bearing design and knowledge of interaction with the refrigerant to maximize performance. Emphasis will be placed on evaluation of synthetic lubricants for both natural and synthetic low GWP refrigerants.

  1. Characterization of used lubricating oil by spectrometric techniques

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Andressa Moreira de, E-mail: andressa@ctaa.embrapa.br [Embrapa Agroindustria de Alimentos, Guaratiba, Rio de Janeiro, RJ (Brazil); Correa, Sergio Machado [Faculdade de Engenharia. Universidade do Estado do Rio de Janeiro (UERJ), Resende, RJ (Brazil); Silva, Glauco Correa da [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Full text: The engine lubricating oil drags all kinds of impurities generated by wear of internal components. Thus, it is necessary to monitor the physical and chemical properties and concentration of metals in lubricants used to determine the appropriate time to replace them. Moreover, one can monitor the wear of the engines through the levels of metals in oils. To achieve these goals, some detection techniques such as Flame atomic absorption spectrometry (FAAS), Inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray fluorescence (XRF), have been widely used to determine metals in lubricating oils and also in other oil derivatives. Thus, some of these techniques were used in this study. Also the technique used was Gas chromatography mass spectrometry (GC / MS) for characterization of chromatographic profile of the engine lubricating oil after use. Through the technique of ICP-OES for method of United States Environmental Protection Agency (USEPA) METHOD 6010B - Inductively coupled plasma optical emission spectrometry was performed to characterize metals in lubricating oil motor, using equipment from ICP-OES Perkin-Elmer{sup R} OPTIMA 3000 ICP-Winlab and software, obtaining the following identification of metals: barium (Ba), calcium (Ca), lead (Pb), copper (Cu), Chromium (Cr), iron (Fe), magnesium (Mg), molybdenum (Mo) and zinc (Zn). Using the XRF technique, through the equipment EDFRX Shimadzu{sup R} model 800HS EDX, Rh tube, applied voltage of 50kV, amperage 100{mu}A, detector Si (Li) cooled with liquid nitrogen and collimator 10mm, we analyzed all the components comprised in the range of Ti to U and Na to SC, identified the following metals: calcium (Ca), zinc (Zn), iron (Fe), copper (Cu), molybdenum (Mo) and nickel (Ni). The characterization was performed by chromatographic methods: USEPA METHOD 5021A - Volatile organic compounds in various sample matrices using equilibrium headspace analysis, USEPA METHOD 8015B - Nonhalogenated Organics

  2. Characterization of used lubricating oil by spectrometric techniques

    International Nuclear Information System (INIS)

    Souza, Andressa Moreira de; Correa, Sergio Machado; Silva, Glauco Correa da

    2011-01-01

    Full text: The engine lubricating oil drags all kinds of impurities generated by wear of internal components. Thus, it is necessary to monitor the physical and chemical properties and concentration of metals in lubricants used to determine the appropriate time to replace them. Moreover, one can monitor the wear of the engines through the levels of metals in oils. To achieve these goals, some detection techniques such as Flame atomic absorption spectrometry (FAAS), Inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray fluorescence (XRF), have been widely used to determine metals in lubricating oils and also in other oil derivatives. Thus, some of these techniques were used in this study. Also the technique used was Gas chromatography mass spectrometry (GC / MS) for characterization of chromatographic profile of the engine lubricating oil after use. Through the technique of ICP-OES for method of United States Environmental Protection Agency (USEPA) METHOD 6010B - Inductively coupled plasma optical emission spectrometry was performed to characterize metals in lubricating oil motor, using equipment from ICP-OES Perkin-Elmer R OPTIMA 3000 ICP-Winlab and software, obtaining the following identification of metals: barium (Ba), calcium (Ca), lead (Pb), copper (Cu), Chromium (Cr), iron (Fe), magnesium (Mg), molybdenum (Mo) and zinc (Zn). Using the XRF technique, through the equipment EDFRX Shimadzu R model 800HS EDX, Rh tube, applied voltage of 50kV, amperage 100μA, detector Si (Li) cooled with liquid nitrogen and collimator 10mm, we analyzed all the components comprised in the range of Ti to U and Na to SC, identified the following metals: calcium (Ca), zinc (Zn), iron (Fe), copper (Cu), molybdenum (Mo) and nickel (Ni). The characterization was performed by chromatographic methods: USEPA METHOD 5021A - Volatile organic compounds in various sample matrices using equilibrium headspace analysis, USEPA METHOD 8015B - Nonhalogenated Organics Using GC

  3. Equilibrium Trust

    OpenAIRE

    Luca Anderlini; Daniele Terlizzese

    2009-01-01

    We build a simple model of trust as an equilibrium phenomenon, departing from standard "selfish" preferences in a minimal way. Agents who are on the receiving end of an other to transact can choose whether to cheat and take away the entire surplus, taking into account a "cost of cheating." The latter has an idiosyncratic component (an agent's type), and a socially determined one. The smaller the mass of agents who cheat, the larger the cost of cheating suffered by those who cheat. Depending o...

  4. Single Common Powertrain Lubricant Development

    Science.gov (United States)

    2012-01-01

    this particular shortcoming of the current MIL specification lubricant lineup . Perameter: Units: Average Std. Dev. Average Std. Dev. Average...variations of each 0.2-second time block of all engagements. Test Number The run number listed on this report is a random number and is not sequential ...is not sequential . Only SwRI® can link this run number to JDQ-96, L0254054, August 3, 2010. Page 2 of3 John Deere JDQ-96 Performed using 1400

  5. Solid Lubricated Rolling Element Bearings

    Science.gov (United States)

    1979-02-15

    lubricant into uneven patches of varnish . This varnish , along with the file-like action of the exposed ball carbides on the relatively softer races, can...its structure. Fluorine , one of the most reactive elements, reacts with graphite without combustion from about 790’F to 1022°F, forming a grey-colored...to allow for molding and machining after molding. 0 Method 2 (Hughes) Impregnating these dense weaves with a Thermid 600 polyimide varnish

  6. Transition to thermohydrodynamic lubrication problem

    Czech Academy of Sciences Publication Activity Database

    Ciuperca, I. S.; Feireisl, Eduard; Jai, M.; Petrov, A.

    2017-01-01

    Roč. 75, č. 3 (2017), s. 391-414 ISSN 0033-569X EU Projects: European Commission(XE) 320078 - MATHEF Institutional support: RVO:67985840 Keywords : free boundary problems * lubrication * asymptotic approach * Stokes equation Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.788, year: 2016 http://www.ams.org/journals/qam/2017-75-03/S0033-569X-2017-01468-X/

  7. Biofluid lubrication for artificial joints

    Science.gov (United States)

    Pendleton, Alice Mae

    This research investigated biofluid lubrication related to artificial joints using tribological and rheological approaches. Biofluids studied here represent two categories of fluids, base fluids and nanostructured biofluids. Base fluids were studied through comparison of synthetic fluids (simulated body fluid and hyaluronic acid) as well as natural biofluids (from dogs, horses, and humans) in terms of viscosity and fluid shear stress. The nano-structured biofluids were formed using molecules having well-defined shapes. Understanding nano-structured biofluids leads to new ways of design and synthesis of biofluids that are beneficial for artificial joint performance. Experimental approaches were utilized in the present research. This includes basic analysis of biofluids' property, such as viscosity, fluid shear stress, and shear rate using rheological experiments. Tribological investigation and surface characterization were conducted in order to understand effects of molecular and nanostructures on fluid lubrication. Workpiece surface structure and wear mechanisms were investigated using a scanning electron microscope and a transmission electron microscope. The surface topography was examined using a profilometer. The results demonstrated that with the adding of solid additives, such as crown ether or fullerene acted as rough as the other solids in the 3-body wear systems. In addition, the fullerene supplied low friction and low wear, which designates the lubrication purpose of this particular particle system. This dissertation is constructed of six chapters. The first chapter is an introduction to body fluids, as mentioned earlier. After Chapter II, it examines the motivation and approach of the present research, Chapter III discusses the experimental approaches, including materials, experimental setup, and conditions. In Chapter IV, lubrication properties of various fluids are discussed. The tribological properties and performance nanostructured biofluids are

  8. Computation of Phase Equilibrium and Phase Envelopes

    DEFF Research Database (Denmark)

    Ritschel, Tobias Kasper Skovborg; Jørgensen, John Bagterp

    formulate the involved equations in terms of the fugacity coefficients. We present expressions for the first-order derivatives. Such derivatives are necessary in computationally efficient gradient-based methods for solving the vapor-liquid equilibrium equations and for computing phase envelopes. Finally, we......In this technical report, we describe the computation of phase equilibrium and phase envelopes based on expressions for the fugacity coefficients. We derive those expressions from the residual Gibbs energy. We consider 1) ideal gases and liquids modeled with correlations from the DIPPR database...... and 2) nonideal gases and liquids modeled with cubic equations of state. Next, we derive the equilibrium conditions for an isothermal-isobaric (constant temperature, constant pressure) vapor-liquid equilibrium process (PT flash), and we present a method for the computation of phase envelopes. We...

  9. Slippery self-lubricating polymer surfaces

    Science.gov (United States)

    Aizenberg, Joanna; Aizenberg, Michael; Cui, Jiaxi; Dunn, Stuart; Hatton, Benjamin; Howell, Caitlin; Kim, Philseok; Wong, Tak Sing; Yao, Xi

    2018-05-08

    The present disclosure describes a strategy to create self-healing, slippery self-lubricating polymers. Lubricating liquids with affinities to polymers can be utilized to get absorbed within the polymer and form a lubricant layer (of the lubricating liquid) on the polymer. The lubricant layer can repel a wide range of materials, including simple and complex fluids (water, hydrocarbons, crude oil and bodily fluids), restore liquid-repellency after physical damage, and resist ice, microorganisms and insects adhesion. Some exemplary applications where self-lubricating polymers will be useful include energy-efficient, friction-reduction fluid handling and transportation, medical devices, anti-icing, optical sensing, and as self-cleaning, and anti-fouling materials operating in extreme environments.

  10. Measured and Predicted Vapor Liquid Equilibrium of Ethanol-Gasoline Fuels with Insight on the Influence of Azeotrope Interactions on Aromatic Species Enrichment and Particulate Matter Formation in Spark Ignition Engines

    Energy Technology Data Exchange (ETDEWEB)

    Ratcliff, Matthew A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); McCormick, Robert L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Burke, Stephen [Colorado State University; Rhoads, Robert [University of Colorado; Windom, Bret [Colorado State University

    2018-04-03

    A relationship has been observed between increasing ethanol content in gasoline and increased particulate matter (PM) emissions from direct injection spark ignition (DISI) vehicles. The fundamental cause of this observation is not well understood. One potential explanation is that increased evaporative cooling as a result of ethanol's high HOV may slow evaporation and prevent sufficient reactant mixing resulting in the combustion of localized fuel rich regions within the cylinder. In addition, it is well known that ethanol when blended in gasoline forms positive azeotropes which can alter the liquid/vapor composition during the vaporization process. In fact, it was shown recently through a numerical study that these interactions can retain the aromatic species within the liquid phase impeding the in-cylinder mixing of these compounds, which would accentuate PM formation upon combustion. To better understand the role of the azeotrope interactions on the vapor/liquid composition evolution of the fuel, distillations were performed using the Advanced Distillation Curve apparatus on carefully selected samples consisting of gasoline blended with ethanol and heavy aromatic and oxygenated compounds with varying vapor pressures, including cumene, p-cymene, 4-tertbutyl toluene, anisole, and 4-methyl anisole. Samples collected during the distillation indicate an enrichment of the heavy aromatic or oxygenated additive with an increase in initial ethanol concentration from E0 to E30. A recently developed distillation and droplet evaporation model is used to explore the influence of dilution effects versus azeotrope interactions on the aromatic species enrichment. The results suggest that HOV-cooling effects as well as aromatic species enrichment behaviors should be considered in future development of predictive indices to forecast the PM potential of fuels containing oxygenated compounds with comparatively high HOV.

  11. A Review of Ionic Liquid Lubricants

    OpenAIRE

    Anthony E. Somers; Patrick C. Howlett; Douglas R. MacFarlane; Maria Forsyth

    2013-01-01

    Due to ever increasing demands on lubricants, such as increased service intervals, reduced volumes and reduced emissions, there is a need to develop new lubricants and improved wear additives. Ionic liquids (ILs) are room temperature molten salts that have recently been shown to offer many advantages in this area. The application of ILs as lubricants in a diverse range of systems has found that these materials can show remarkable protection against wear and significantly reduce friction in th...

  12. Lubricant test for punching and blanking

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2003-01-01

    Punching/blanking is one of the tribologically wise most severe metal forming processes.Insu $cient lubrication leads to heavy pick-up of work piece material on the punch stem,bad tolerances and eventual breakdown of the punch due to excessive backstroke force,especially in case of tribologically...... of alternative lubricants the present paper describes a new lubricant test for punching....

  13. Lubrication for hot working of titanium alloys

    International Nuclear Information System (INIS)

    Gotlib, B.M.

    1980-01-01

    The isothermal lubrication of the following composition is suggested, wt. %: aluminium powder 4-6, iron scale 15-25, vitreous enamel up to 100. The lubricant improves forming and decreases the danger of the metal fracture when titanium alloys working. It is advisable to use the suggested lubrication when stamping thin-walled products of titanium alloys at the blank temperature from 700 to 1000 deg C [ru

  14. Development of High Temperature Solid Lubricant Coatings

    National Research Council Canada - National Science Library

    Bhattacharya, Rabi

    1999-01-01

    ... environment. To test this approach, UES and Cleveland State University have conducted experiments to form cesium oxythiotungstate, a high temperature lubricant, on Inconel 718 surface from composite coatings...

  15. Ecotoxicological study of used lubricating oil

    International Nuclear Information System (INIS)

    Wong, P.K.; Chan, W.L.; Wang, J.; Wong, C.K.

    1995-01-01

    Used lubricating oil is more toxic than crude oil and fuel oil since it contains comparatively high levels of heavy metals and polycyclic aromatic hydrocarbons (PAHs). No detail toxicological study has been conducted to evaluate the hazards of used lubricating oil to the environment. This study reports a battery of bioassays using bacteria (Microtox test and Mutatox test), algae, amphipod and shrimp larvae to determine the toxicity of water soluble fraction of used lubricating oil. The results will be used to formulate a complete and extensive ecotoxicological assessment of the impacts of used lubricating oil on aquatic environment

  16. On the lubrication mechanism of detonation-synthesis nanodiamond additives in lubricant composites

    Science.gov (United States)

    Shepelevskii, A. A.; Esina, A. V.; Voznyakovskii, A. P.; Fadin, Yu. A.

    2017-09-01

    The lubrication of detonation-synthesis diamond additives in lubricant composites has been discussed. The mechanism of interaction between nanodiamonds and friction surface has been shown to depend on the applied load. Two models of the lubrication of nanodiamonds and the conditions for their validity have also been proposed.

  17. Lubrication from mixture of boric acid with oils and greases

    Science.gov (United States)

    Erdemir, Ali

    1995-01-01

    Lubricating compositions including crystalline boric acid and a base lubricant selected from oils, greases and the like. The lubricity of conventional oils and greases can also be improved by adding concentrates of boric acid.

  18. Strip reduction testing of lubricants developed during ENFORM project

    DEFF Research Database (Denmark)

    Gazvoda, S.; Andreasen, Jan Lasson; Olsson, David Dam

    Strip reduction testing of lubricants developed during ENFORM project. Experiments were conducted with the strip reduction test [1] in order to classify experimental lubricants, developed during concerned project. One reference lubricant was used during testing....

  19. Nuclear fuel handling grapple carriage with self-lubricating bearing

    International Nuclear Information System (INIS)

    Wade, E.E.

    1978-01-01

    Disclosed is a nuclear fuel handling grapple carriage having a bearing with a lubricant reservoir that is capable of being refilled when the bearing and reservoir are submerged in a lubricant pool. The lubricant reservoir supplies lubricant to the bearing while the bearing allows a small amount of lubricant to leak passed appropriately placed seals creating a positive out flow of lubricant thereby preventing foreign material from entering the bearing

  20. Applicability of the theory of thermodynamic similarity to predict the enthalpies of vaporization of aliphatic aldehydes

    Science.gov (United States)

    Esina, Z. N.; Korchuganova, M. R.

    2015-06-01

    The theory of thermodynamic similarity is used to predict the enthalpies of vaporization of aliphatic aldehydes. The predicted data allow us to calculate the phase diagrams of liquid-vapor equilibrium in a binary water-aliphatic aldehyde system.

  1. Improvement of Oil-Vapor Treatment Facility for Wolsong Unit 3,4

    International Nuclear Information System (INIS)

    Kim, Jeong Guk; Kwon, S. W.; Lee, H. S.

    2009-11-01

    With the purpose to minimize an oil-vapor discharge to the atmosphere and to be an environmentally friendly nuclear power plant by an improvement of mist eliminator for turbine lubricant system at Wolsong Nuclear Power Plant Unit 3,4, this project - project name : Improvement of Oil-vapor Treatment Facility for Wolsong Unit 3,4 - was conducted for six months (from Apr. 15, 2009 to Oct. 14, 2009). This Project contains Oil-vapor Source and Environmental Regulation, Analysis on the Present Oil-vapor Treatment Facility, Improvement of Oil-vapor Treatment Facility, Test Facility Design, Fabrication, Installation, Test Operation, Evaluation of the Facility

  2. Improved Ionic Liquids as Space Lubricants, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Ionic liquids are candidate lubricant materials. However for application in low temperature space mechanisms their lubrication performance needs to be enhanced. UES...

  3. Aminodisulfides as additives to lubricants

    Energy Technology Data Exchange (ETDEWEB)

    Balin, A.I.; Tarasevich, V.B.; Veretenova, T.N.

    1980-01-01

    A study was carried out and tehcnology developed for producing sulfur-nitrogen containing additives of the type of aminodisulfide by interaction of beta, beta-dichlordialkyl (aryl) disulfides with diethanolamine in a medium of sulfur-diethanolamine. The 2,2'-bis-(diethanol)-dialkyl(aryl) disulfides obtained do not hydrolyze in aqueous soltuions of alkalis, exhibit rather high antiscoring properties and are recommended for tests as active additives of high pressure to SOZH and technological lubricants of the oil and emulsion types.

  4. Lubrication pressure and fractional viscous damping effects on the spring-block model of earthquakes

    Science.gov (United States)

    Tanekou, G. B.; Fogang, C. F.; Kengne, R.; Pelap, F. B.

    2018-04-01

    We examine the dynamical behaviours of the "single mass-spring" model for earthquakes considering lubrication pressure effects on pre-existing faults and viscous fractional damping. The lubrication pressure supports a part of the load, thereby reducing the normal stress and the associated friction across the gap. During the co-seismic phase, all of the strain accumulated during the inter-seismic duration does not recover; a fraction of this strain remains as a result of viscous relaxation. Viscous damping friction makes it possible to study rocks at depth possessing visco-elastic behaviours. At increasing depths, rock deformation gradually transitions from brittle to ductile. The fractional derivative is based on the properties of rocks, including information about previous deformation events ( i.e., the so-called memory effect). Increasing the fractional derivative can extend or delay the transition from stick-slip oscillation to a stable equilibrium state and even suppress it. For the single block model, the interactions of the introduced lubrication pressure and viscous damping are found to give rise to oscillation death, which corresponds to aseismic fault behaviour. Our result shows that the earthquake occurrence increases with increases in both the damping coefficient and the lubrication pressure. We have also revealed that the accumulation of large stresses can be controlled via artificial lubrication.

  5. The Lubricity of Glycerol and its Solutions

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Jakobsen, J.

    2016-01-01

    Glycerol has been recognised as an excellent diesel fuel and lubricant. It is a liquid that can originate from the transesterification of plant oil that also results in plant oil metyl (or ethyl) ester (biodiesel). Machine elements lubricated by glycerol show very low friction, in fact lower than...

  6. Ionic liquids as lubricant additives: A review

    International Nuclear Information System (INIS)

    Zhou, Yan; Qu, Jun

    2016-01-01

    In pursuit of energy efficiency and durability throughout human history, advances in lubricants have always played important roles. Ionic liquids (ILs) are room-temperature molten salts that possess unique physicochemical properties and have shown great potential in many applications with lubrication as one of the latest. While earlier work (2001–2011) primarily explored the feasibility of using ILs as neat or base lubricants, using ILs as lubricant additives has become the new focal research topic since the breakthrough in ILs’ miscibility in nonpolar hydrocarbon oils in early 2012. This work reviews the recent advances in developing ILs as additives for lubrication with an attempt to correlate among the cationic and anionic structures, oil-solubility, and other relevant physicochemical properties, and lubricating behavior. Effects of the concentration of ILs in lubricants and the compatibility between ILs and other additives in the lubricant formulation on the tribological performance are described followed by a discussion of wear protection mechanism based on tribofilm characterization. As a result, future research directions are suggested at the end.

  7. A Biomimetic Approach to Lubricate Engineering Materials

    DEFF Research Database (Denmark)

    Røn, Troels

    lubrication characteristic is dominant via ‘selfhealing’ mechanism. The glycosylated FpHYD5 revealed a better lubrication than HFBI. Two type II hydrophobins function more favorably compared to synthetic amphiphilic copolymer, PEO-PPO-PEO, with a similar molecular weight. This is ascribed to higher amount...

  8. Lubricity characteristics of marine distillate fuels

    Energy Technology Data Exchange (ETDEWEB)

    Crutchley, Ian [Innospec Fuel Specialties, Ellesmere Port (United Kingdom); Green, Michael [Intertek Lintec ShipCare Services, Darlington (United Kingdom)

    2012-08-15

    This article from Innospec Fuel Specialties, Ellesmere Port, UK, and Intertek Lintec ShipCare Services, Darlington, UK, examines the lubricity characteristics of marine distillate fuels available today in relation to the requirements and limits imposed in ISO8217:2010. It will estimate expected failure rates and also asses the perceived relationship between lubricity, sulphur content and viscosity. (orig.)

  9. Lubricants : the lifeblood of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Tremblay, Y. [Petro-Canada, Calgary, AB (Canada)

    2009-07-01

    With the significant investments in wind turbine equipment, companies need to exercise due diligence when it comes to the types of lubricants and fluids used. Mechanical and equipment issues can often be eliminated with improved maintenance practices and the appropriate selection of lubricants. This presentation discussed lubricants as being the lifeblood of wind turbines. The presentation first provided an overview and discussed wind turbine trends and application trends. The technical aspects of fluid formation were presented. Lubrication maintenance practices and oil monitoring were discussed. Last, key industry tests, and OEM specifications for bearings, gearboxes, and wind turbines were identified. It was concluded that improved maintenance practices in combination with the correct lubricant selection can address several operating problems. figs.

  10. Lubricant Test Methods for Sheet Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson

    2008-01-01

    appearing in different sheet forming operations such as stretch forming, deep drawing, ironing and punching. The laboratory tests have been especially designed to model the conditions in industrial production. Application of the tests for evaluating new lubricants before introducing them in production has......Sheet metal forming of tribologically difficult materials such as stainless steel, Al-alloys and Ti-alloys or forming in tribologically difficult operations like ironing, punching or deep drawing of thick plate requires often use of environmentally hazardous lubricants such as chlorinated paraffin...... oils in order to avoid galling. The present paper describes a systematic research in the development of new, environmentally harmless lubricants focusing on the lubricant testing aspects. A system of laboratory tests has been developed to study the lubricant performance under the very varied conditions...

  11. Semi-empirical correlation for binary interaction parameters of the Peng-Robinson equation of state with the van der Waals mixing rules for the prediction of high-pressure vapor-liquid equilibrium.

    Science.gov (United States)

    Fateen, Seif-Eddeen K; Khalil, Menna M; Elnabawy, Ahmed O

    2013-03-01

    Peng-Robinson equation of state is widely used with the classical van der Waals mixing rules to predict vapor liquid equilibria for systems containing hydrocarbons and related compounds. This model requires good values of the binary interaction parameter kij . In this work, we developed a semi-empirical correlation for kij partly based on the Huron-Vidal mixing rules. We obtained values for the adjustable parameters of the developed formula for over 60 binary systems and over 10 categories of components. The predictions of the new equation system were slightly better than the constant-kij model in most cases, except for 10 systems whose predictions were considerably improved with the new correlation.

  12. Double angle seal forming lubricant film

    Science.gov (United States)

    Ernst, William D.

    1984-01-01

    A lubricated piston rod seal which inhibits gas leaking from a high pressure chamber on one side of the seal to a low pressure chamber on the other side of the seal. A liquid is supplied to the surface of the piston rod on the low pressure side of the seal. This liquid acts as lubricant for the seal and provides cooling for the rod. The seal, which can be a plastic, elastomer or other material with low elastic modulus, is designed to positively pump lubricant through the piston rod/seal interface in both directions when the piston rod is reciprocating. The capacity of the seal to pump lubricant from the low pressure side to the high pressure side is less than its capacity to pump lubricant from the high pressure side to the low pressure side which ensures that there is zero net flow of lubricant to the high pressure side of the seal. The film of lubricant between the seal and the rod minimizes any sliding contact and prevents the leakage of gas. Under static conditions gas leakage is prevented by direct contact between the seal and the rod.

  13. Nanopolishing by colloidal nanodiamond in elastohydrodynamic lubrication

    Energy Technology Data Exchange (ETDEWEB)

    Shirvani, Khosro A., E-mail: Khosro.asgharishir@bison.howard.edu; Mosleh, Mohsen; Smith, Sonya T. [Howard University, Department of Mechanical Engineering (United States)

    2016-08-15

    In this paper, the feasibility of using explosion synthesized diamond nanoparticles with an average particle size (APS) of 3–5 nm with a concentration of 1 % by weight for improving lubrication and friction in elastohydrodynamic lubrication (EHL) was investigated. Owing to the orders of magnitude increase in the viscosity of the lubricant in the EHL contact zone, diamond nanoparticles in the lubricant polish the surfaces at the nanoscale which decreases the composite roughness of contacting surfaces. The reduced composite roughness results in an increased film thickness ratio which yields lower friction. In the numerical analysis, governing equations of lubricant flow in the full elastohydrodynamic lubrication were solved, and the shear stress distribution over the fluid film was calculated. Using an abrasion model and the shear stress distribution profile, the material removal by the nanofluid containing nanoparticles and the resultant surface roughness were determined. The numerical analysis showed that in full EHL regime, the nanolubricant can reduce the composite roughness of moving surfaces. Experimental results from prior studies which exhibited surface polishing by such nanolubricants in boundary, mixed, and full elastohydrodynamic lubrication were used for comparison to the numerical model.

  14. Nanopolishing by colloidal nanodiamond in elastohydrodynamic lubrication

    Science.gov (United States)

    Shirvani, Khosro A.; Mosleh, Mohsen; Smith, Sonya T.

    2016-08-01

    In this paper, the feasibility of using explosion synthesized diamond nanoparticles with an average particle size (APS) of 3-5 nm with a concentration of 1 % by weight for improving lubrication and friction in elastohydrodynamic lubrication (EHL) was investigated. Owing to the orders of magnitude increase in the viscosity of the lubricant in the EHL contact zone, diamond nanoparticles in the lubricant polish the surfaces at the nanoscale which decreases the composite roughness of contacting surfaces. The reduced composite roughness results in an increased film thickness ratio which yields lower friction. In the numerical analysis, governing equations of lubricant flow in the full elastohydrodynamic lubrication were solved, and the shear stress distribution over the fluid film was calculated. Using an abrasion model and the shear stress distribution profile, the material removal by the nanofluid containing nanoparticles and the resultant surface roughness were determined. The numerical analysis showed that in full EHL regime, the nanolubricant can reduce the composite roughness of moving surfaces. Experimental results from prior studies which exhibited surface polishing by such nanolubricants in boundary, mixed, and full elastohydrodynamic lubrication were used for comparison to the numerical model.

  15. Application of a Biodegradable Lubricant in a Diesel Vehicle

    DEFF Research Database (Denmark)

    Schramm, Jesper

    2003-01-01

    , NOx, THC, PM, lubricant-SOF and PAH from one diesel and one gasoline type vehicle using biodegradable lubricants and conventional lubricants. This paper describes the results of the experiments with the diesel type vehicle only. Lubricant consumption and fuel consumption are other important parameters...

  16. A study of mechanisms of liquid lubrication in metal forming

    DEFF Research Database (Denmark)

    Bech, Jakob Ilsted; Bay, Niels; Eriksen, Morten

    1998-01-01

    Applying a transparent tool technique the lubrication in plane strip drawing of aluminium sheet is studied providing the strip with surface pockets for entrapment of lubricant. The compression and eventual escape of trapped lubricant by Micro Plasto HydroDynamic Lubrication (MPHDL) as well as Micro...

  17. Vegetable oil basestocks for lubricants

    Directory of Open Access Journals (Sweden)

    Garcés, Rafael

    2011-03-01

    Full Text Available The use of vegetable biodegradable basestocks for lubricant oils present several advantages over the much more extended mineral bases. These advantages refer to biodegradability, a renewable feedstock of local production, lubricant and viscosity index and lower costs than synthetic lubricant bases. Despite these benefits, their use in industry and motor vehicles is not yet extensive due their lower stability and higher pour points. Vegetable oils are esters of fatty acids and glycerol, and their physicochemical properties rely mainly on the composition of their acyl moieties. Thus, to assure the maximum levels of stability while maintaining acceptable behavior at low temperatures, monounsaturated fatty acids are preferred for this purpose. The presence of natural antioxidants also improves the properties of these vegetable based stocks as lubricants. These oils usually require additives to improve their viscosity value, oxidative stability and properties at low temperatures. In the present work, the different sources of vegetable oils appropriate for biolubricant production were reviewed. Their properties and the future improvement of the oil bases, oil based stock production, uses and additives are discussed.

    El uso de bases vegetales biodegradables para aceites lubricantes presenta varias ventajas sobre las mucho más extendidas bases minerales. Estas ventajas se centran sobre todo en su biodegradabilidad, en ser un recurso renovable de producción local, en su lubricidad y en su índice de viscosidad, presentando además costes más bajos que las bases sintéticas. Sin embargo, estas ventajas no han extendido el uso de bases vegetales ni en industria ni en automoción debido a su menor estabilidad y sus mayores puntos críticos de fluidez. Los aceites vegetales son ésteres de ácidos grasos y glicerol y sus propiedades físico-químicas dependen principalmente de su composición acílica. Así, para asegurar los máximos niveles de

  18. Lubrication of nuclear reactor components

    International Nuclear Information System (INIS)

    Wild, E.; Mack, K.J.

    1978-01-01

    Safe operation of liquid metal cooled nuclear reactors requires a knowledge of the tribological behaviour of contacting components at high temperatures with slow relative movement at high frictional loads in a chemically aggressive environment. Experiments have been performed on various material combinations in liquid sodium and argon. Because of the small sliding movements, hydrodynamic lubrication is not expected and thus surface finish is an important factor. Tests have been performed on brushed, ground and lapped surfaces. Among the material combinations tested a CrC-coating on a 1.4961 stainless steel substrate performed well. Friction coefficients of 0.35-0.5 in argon and 0.1-1.2 in liquid sodium were recorded. (author)

  19. Measurement and analysis of transient vaporization in oxide fuel materials

    International Nuclear Information System (INIS)

    Benson, D.A.; Bergeron, E.G.

    1979-01-01

    This paper describes a series of experiments in which samples are heated to produce high vapor pressure states in times of 10 -6 to 10 -3 seconds. Experimental measurements of vapor pressures over fresh UO 2 from the pulsed electron beam and pulsed reactor heating tests are presented and compared with other high temperature data. The interpretation of the vapor pressure measured in the tests is discussed in detail. Effects of original sample stoichiometry, chemical interactions with the container and non-equilibrium evaporation due to induced temperature gradients are discussed. Special attention is given to dynamic behavior in rapid heating and vaporization of the oxide due to chemical non-equilibrium. Finally, similar projected reactor experiments on irradiated fuel are described and vapor pressure predictions made using available equilibrium models. A discussion of information accessible from such future tests and its importance is presented. (orig.) [de

  20. Mobile vapor recovery and vapor scavenging unit

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  1. Graphite and Hybrid Nanomaterials as Lubricant Additives

    Directory of Open Access Journals (Sweden)

    Zhenyu J. Zhang

    2014-04-01

    Full Text Available Lubricant additives, based on inorganic nanoparticles coated with organic outer layer, can reduce wear and increase load-carrying capacity of base oil remarkably, indicating the great potential of hybrid nanoparticles as anti-wear and extreme-pressure additives with excellent levels of performance. The organic part in the hybrid materials improves their flexibility and stability, while the inorganic part is responsible for hardness. The relationship between the design parameters of the organic coatings, such as molecular architecture and the lubrication performance, however, remains to be fully elucidated. A survey of current understanding of hybrid nanoparticles as lubricant additives is presented in this review.

  2. The role of lubricant analysis in maximizing lubricant and equipment life

    International Nuclear Information System (INIS)

    Janis, J.

    1995-01-01

    Lubricant analysis has always played an important yet somewhat invisible role in equipment health monitoring. At its most primitive, simple observations and field testing alert equipment operators to changing conditions. At its most advanced, data from performance and analytical tests are used to develop or select optimum lubricants for service, stretch drain intervals, predict remaining equipment life and identify potential equipment or system problems at an incipient stage. Coupled with thermography and vibration analysis, lubricant analysis can become a major component of a comprehensive predictive maintenance (PM) program. Ontario Hydro finds itself at a turning point regarding the use and monitoring of lubricants. Increasing emphasis on equipment reliability and plant life extension, coupled with major, recent changes in lubricant composition in response to environmental, energy and safety concerns, forces an upgrading of many aspects of lubricant monitoring so that it may establish itself as a key part of modern PM practices. This paper discusses some of these aspects. (author)

  3. Potential of Palm Olein as Green Lubricant Source: Lubrication Analysis and Chemical Characterisation

    International Nuclear Information System (INIS)

    Darfizzi Derawi; Jumat Salimon

    2014-01-01

    Palm olein (PO o ) is widely used as edible oil in tropical countries. The lubrication properties and chemical compositions of PO o being considered to be used as renewable raw material for bio lubricant synthesis. PO o is suitable to be used directly as bio lubricant for medium temperature industrial applications. Palm olein has good viscosity index, oxidative stability, flash and fire point as a lubricant source. PO o contains unsaturated triacylglycerols (TAG): Palmitin-Olein-Olein, POO (33.3 %), Palmitin-Olein-Palmitin, POP (29.6 %), which are very important to produce good lubricant properties. This unsaturated bond is preferable in chemical modification to produce bio lubricant. The chemical compositions of PO o were tested by using high performance liquid chromatography (HPLC) and gas chromatography (GC) techniques. (author)

  4. Vapor equilibrium data for the systems Ar--N/sub 2/, Kr--Ar, Kr--N/sub 2/, and Xe--Kr, as well as the liquidus lines of solid xenon and of solid krypton in liquid air component mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Mastera, S J

    1977-01-15

    The knowledge of vapor-liquid equilibrium data of real gas mixtures makes possible a precise design of a low temperature distillation system. The noble gas isotopes Kr and Xe are formed as a result of nuclear fission. They reach the off-gas, where they must be separated by cryogenic methods, among others, in order to reduce radiological contamination of the environment. Consequently, an equilibrium apparatus was constructed inhouse, which worked according to a dynamical measurement method. The following low temperature measurements were performed with this apparatus: (1) to test the apparatus with the Ar--N/sub 2/ system, at temperatures of 80, 85, 90, 95, and 100 degrees K; (2) with the Kr--Ar system, at temperatures of 115, 116.5, 120, and 125 degrees K; (3) with the Kr--N/sub 2/ system, at temperatures of 100, 105, at 110 degrees K in the N/sub 2/-rich existence range of the liquid phase above the solubility limit, and at temperatures of 115, 120, and 125 degrees K in the entire concentration range. No data at all were previously known about this important system. (4) In the Xe-Kr system, at temperatures of 150, 155, and 160 degrees K, in the Kr-rich liquid existence range above the solubility limit, and at the temperature steps 165, 166, and 170 degrees in the entire concentration range. The consistency of the equilibrium data thus determined was tested with the computer program SYMFIT. These measurements were completed by determining the solubility limits (= liquidus lines) of solid Kr in a liquid Kr--Ar mixture or in a liquid Kr--N/sub 2/ mixture, as well as the solubility limit of solid Xe in a liquid Xe--Kr mixture. The measurement points for the liquidus lines were associated with the respective pressure and respective temperature over the entire concentration range. The experimentally determined data are displayed on tables and graphs. The utilized measurement equipment, with its glass equilibrium cell, is described.

  5. 49 CFR 396.5 - Lubrication.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS INSPECTION, REPAIR, AND MAINTENANCE § 396.5 Lubrication. Every motor carrier shall ensure that each motor vehicle subject to its control is...

  6. Excellent lubricating behavior of Brasenia schreberi mucilage.

    Science.gov (United States)

    Li, Jinjin; Liu, Yuhong; Luo, Jianbin; Liu, Pengxiao; Zhang, Chenhui

    2012-05-22

    The present work reports an excellent lubrication property of an aquatic plant called Brasenia schreberi (BS). To investigate the lubrication characteristics of the BS mucilage, a novel measuring system is designed, and an ultralow friction coefficient about 0.005 between the mucilage and glass surface has been obtained. It is found that the ultralow friction is closely related to the structure of mucilage and water molecules in the mucilage. The microstructure analysis indicates that the mucilage surrounding BS forms a kind of polysaccharide gel with many nanosheets. A possible lubrication mechanism is proposed that the formation of hydration layers among these polymer nanosheets with plenty of bonded water molecules causes the ultralow friction. The excellent lubrication property has a potential application for reducing the friction between a glossy pill coated with such layer of mucilage and people's throats.

  7. Nanoscale Organic−Inorganic Hybrid Lubricants

    KAUST Repository

    Kim, Daniel; Archer, Lynden A.

    2011-01-01

    Silica (SiO2) nanoparticles densely grafted with amphiphilic organic chains are used to create a family of organic-inorganic hybrid lubricants. Short sulfonate-functionalized alkylaryl chains covalently tethered to the particles form a dense corona

  8. Fuels and Petroleum, Oil & Lubricants (POL) Laboratories

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuels and Lubricants Technology Team operates and maintains the Fuels and POL Labs at TARDEC. Lab experts adhere to standardized American Society for Testing and...

  9. Biodegradable lubricants - ''the solution for future?''

    International Nuclear Information System (INIS)

    Jahan, A.

    1997-01-01

    The environmental impact of lubricants use concern the direct effects from spills but also the indirect effects such as their lifetime and the emissions from thermal engines. The biodegradable performances and the toxicity are the environmental criteria that must be taken into account in the development and application of lubricants together with their technical performances. This paper recalls first the definition of biodegradable properties of hydrocarbons and the standardized tests, in particular the CEC and AFNOR tests. Then, the biodegradable performances of basic oils (mineral, vegetal, synthetic esters, synthetic hydrocarbons etc..), finite lubricants (hydraulic fluids..) and engine oils is analyzed according to these tests. Finally, the definition of future standards would take into account all the environmental characteristics of the lubricant: biodegradable performances, energy balance (CO 2 , NOx and Hx emissions and fuel savings), eco-toxicity and technical performances (wearing and cleanliness). (J.S.)

  10. Determining minimum lubrication film for machine parts

    Science.gov (United States)

    Hamrock, B. J.; Dowson, D.

    1978-01-01

    Formula predicts minimum film thickness required for fully-flooded ball bearings, gears, and cams. Formula is result of study to determine complete theoretical solution of isothermal elasto-hydrodynamic lubrication of fully-flooded elliptical contacts.

  11. Lubrication and cooling for high speed gears

    Science.gov (United States)

    Townsend, D. P.

    1985-01-01

    The problems and failures occurring with the operation of high speed gears are discussed. The gearing losses associated with high speed gearing such as tooth mesh friction, bearing friction, churning, and windage are discussed with various ways shown to help reduce these losses and thereby improve efficiency. Several different methods of oil jet lubrication for high speed gearing are given such as into mesh, out of mesh, and radial jet lubrication. The experiments and analytical results for the various methods of oil jet lubrication are shown with the strengths and weaknesses of each method discussed. The analytical and experimental results of gear lubrication and cooling at various test conditions are presented. These results show the very definite need of improved methods of gear cooling at high speed and high load conditions.

  12. Tribology experiment. [journal bearings and liquid lubricants

    Science.gov (United States)

    Wall, W. A.

    1981-01-01

    A two-dimensional concept for Spacelab rack 7 was developed to study the interaction of liquid lubricants and surfaces under static and dynamic conditions in a low-gravity environment fluid wetting and spreading experiments of a journal bearing experiments, and means to accurately measure and record the low-gravity environment during experimentation are planned. The wetting and spreading process of selected commercial lubricants on representative surface are to the observes in a near-zero gravity environment.

  13. Investigation of lubricants under boundary friction

    Science.gov (United States)

    Heidebroek, E; Pietsch, E

    1942-01-01

    Numerous observations of such lubrication processes within range of boundary friction on journal bearings and gear tooth profiles have strengthened the supposition that it should be possible to study the attendant phenomena with engineering methods and equipment. These considerations formed the basis of the present studies, which have led to the discovery of relations governing the suitability of bearing surfaces and the concept of "lubricating quality."

  14. Noise estimation of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2003-01-01

    Noise estimating procedures of oil lubricated journal bearings are presented. Nonlinear analysis of rotor-bearing system including unbalance mass of the rotor is performed in order to obtain acoustical properties of the bearing. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Noise estimating procedures presented in this paper could aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  15. Advanced lubrication systems and materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, S.

    1998-05-07

    This report described the work conducted at the National Institute of Standards and Technology under an interagency agreement signed in September 1992 between DOE and NIST for 5 years. The interagency agreement envisions continual funding from DOE to support the development of fuel efficient, low emission engine technologies in terms of lubrication, friction, and wear control encountered in the development of advanced transportation technologies. However, in 1994, the DOE office of transportation technologies was reorganized and the tribology program was dissolved. The work at NIST therefore continued at a low level without further funding from DOE. The work continued to support transportation technologies in the development of fuel efficient, low emission engine development. Under this program, significant progress has been made in advancing the state of the art of lubrication technology for advanced engine research and development. Some of the highlights are: (1) developed an advanced high temperature liquid lubricant capable of sustaining high temperatures in a prototype heat engine; (2) developed a novel liquid lubricant which potentially could lower the emission of heavy duty diesel engines; (3) developed lubricant chemistries for ceramics used in the heat engines; (4) developed application maps for ceramic lubricant chemistry combinations for design purpose; and (5) developed novel test methods to screen lubricant chemistries for automotive air-conditioning compressors lubricated by R-134a (Freon substitute). Most of these findings have been reported to the DOE program office through Argonne National Laboratory who manages the overall program. A list of those reports and a copy of the report submitted to the Argonne National Laboratory is attached in Appendix A. Additional reports have also been submitted separately to DOE program managers. These are attached in Appendix B.

  16. New Lubricants Protect Machines and the Environment

    Science.gov (United States)

    2007-01-01

    In 1994, NASA and Lockheed Martin Space Operations commissioned Sun Coast Chemicals of Daytona Inc to develop a new type of lubricant that would be safe for the environment and help "grease the wheels" of the shuttle-bearing launcher platform. Founded in 1989, Sun Coast Chemicals is known amongst the racing circuit for effective lubricants that help overcome engine and transmission problems related to heat and wear damage. In a matter of weeks, Sun Coast Chemical produced the biodegradable, high-performance X-1R Crawler Track Lube. In 1996, Sun Coast Chemical determined there was a market for this new development, and introduced three derivative products, Train Track Lubricant, Penetrating Spray Lubricant, and Biodegradable Hydraulic Fluid, and then quickly followed with a gun lubricant/cleaner and a fishing rod and reel lubricant. Just recently, Sun Coast introduced the X-1R Corporation, which folds the high-performance, environmentally safe benefits into a full line of standard automotive and specially formulated racing products. The entire X-1R automotive product line has stood up to rigorous testing by groups such as the American Society of Mechanical Engineers, the Swedish National Testing and Research Institute, the Department of Mechanical Engineering at Oakland University (Rochester, Michigan), and Morgan-McClure Motorsports (Abingdon, Virginia). The X-1R Corporation also markets "handy packs" for simple jobs around the house, consisting of a multi-purpose, multi-use lubricant and grease. In 2003, The X-1R Corporation teamed up with Philadelphia-based Penn Tackle Manufacturing Co., a leading manufacturer of fishing tackle since 1932, to jointly develop and market a line of advanced lubrication products for saltwater and freshwater anglers

  17. A demonstration experiment for studying the properties of saturated vapor

    Science.gov (United States)

    Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.

    2017-11-01

    The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation vapor, partial pressure, and the dependence of saturated vapor pressure on temperature.

  18. Calculation of vapor pressure of fission product fluorides and oxyfluorides

    International Nuclear Information System (INIS)

    Roux, J.P.

    1976-03-01

    The equilibrium diagrams of the condensed phases - solid and liquid - and vapor phase are collected for the principal fluorides and oxyfluorides of fission product elements (atomic number from 30 to 66). These diagrams are used more particularly in fuel reprocessing by fluoride volatility process. Calculations and curves (vapor pressure in function of temperature) are processed using a computer program given in this report [fr

  19. Determinan Kepuasan Pelanggan Pada Produk Pertamina Lubricants

    Directory of Open Access Journals (Sweden)

    Berto Mulia Wibawa

    2017-02-01

    Full Text Available Determinants of Customer Satisfaction at Pertamina's Lubricants ProductLubricant industry is one of the strategic industries in around the world. The potential of the lubricant industry in Indonesia grows rapidly along with the increasing demand and the number of a vehicle from year to year. This study aims to analyze factors that influencing customer satisfaction Pertamina Lubricants product and measure how far the customer satisfaction level of its product. This study observed eight categories of Pertamina Lubricants product, with quota sampling technique where each category of the product taken 30 samples, so the total number of the sample are 240 respondents. Multiple linear regression and customer satisfaction index were used in this study. The study finds brand popularity has the most significant effect on customer satisfaction, followed by price and durability. Customer satisfaction level stands at 78 percent, which means belongs in the satisfied category. Managerial implications of this study provide strategies for Pertamina Lubricants to improve their business performance and to increase the level of customer satisfactionDOI:  10.15408/ess.v7i1.4309  

  20. Achievement report for fiscal 1998 on area consortium research and development business, 1st year. Area consortium energy research and development (molding material processing eco-system using powder lubricant); 1998 nendo chiiki consortium energy kenkyu kaihatsu bun'ya. Funtai rikei junkatsuzai wo mochiita sokeizai kako eko system no kenkyu kaihatsu (dai 1 nendo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    A material processing technology demanding but low energy and cost and causing low environmental impact was developed using a powder lubricant in a closed metal die system. An inorganic powder excellent in adhesiveness as lubricant was discovered. Powder lubricants for die casting and new carbon lubricants for metal die forging were also developed. In a test in an eco-die casting system, it was found that power was better than water solution in terms of finish and energy efficiency. In the development of a metal forging system using a powder lubricant, existing graphite lubricants and new powder lubricants containing fullerene were subjected to evaluation (ring tests). Two types of graphite solutions now in use and two powder lubricants were evaluated by the ring tests, and this enabled the comprehension of powder lubricant characteristics. For the development of a die casting system requiring no lubricant, a metal die surface treatment method was found that produces a surface excellent in resisting erosion by the application of the aluminizing ion nitriding composite treatment method. In addition, wettability was compared between a PVD (physical vapor deposition)-formed nitride film and the powder lubricant constituents. The report also refers to surveys conducted for commercialization. (NEDO)

  1. Reduced Need of Lubricity Additives in Soybean Oil Blends Under Boundary Lubrication Conditions

    Science.gov (United States)

    Converging prices of vegetable oils and petroleum, along with increased focus on renewable resources, gave more momentum to vegetable oil lubricants. Boundary lubrication properties of four Extreme Pressure (EP) additive blends in conventional Soy Bean Oil (SBO) and Paraffinic Mineral Oil (PMO) of ...

  2. Boundary lubrication of bearing steel in water-based lubricants with functional additives

    NARCIS (Netherlands)

    Wu, Y.

    2017-01-01

    This thesis focuses on the effect of additives on boundary lubrication of bearing steel for water-based lubrication systems. The oil-in-water (O/W) emulsion and the water-glycol based liquid were selected as the base fluids for research. Sulfur compounds, nitrogen heterocycles and graphene

  3. Compatibility of lubricant additives with HFC refrigerants and synthetic lubricants. Final report, Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Cavestri, R.C. [Imagination Resources, Inc., Dublin, OH (United States)

    1997-07-01

    Part one of this research provides manufacturers of components of air-conditioning and refrigeration equipment with a useful list of lubricant additives, sources, functional properties and chemical species. The list in part one is comprised of domestic lubricant additive suppliers and the results of a literature search that was specifically targeted for additives reported to be useful in polyolester chemistry.

  4. Petroleum Vapor Intrusion

    Science.gov (United States)

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

  5. Are Ionic Liquids Good Boundary Lubricants? A Molecular Perspective

    Directory of Open Access Journals (Sweden)

    Romain Lhermerout

    2018-01-01

    Full Text Available The application of ionic liquids as lubricants has attracted substantial interest over the past decade and this has produced a rich literature. The aim of this review is to summarize the main findings about frictional behavior of ionic liquids in the boundary lubrication regime. We first recall why the unusual properties of ionic liquids make them very promising lubricants, and the molecular mechanisms at the origin of their lubricating behavior. We then point out the main challenges to be overcome in order to optimise ionic liquid lubricant performance for common applications. We finally discuss their use in the context of electroactive lubrication.

  6. Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner.

    Science.gov (United States)

    Kim, Chul Jin; Choi, Hyo Hyun; Sohn, Chae Hoon

    2011-01-15

    Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 °C. First, its auto-ignition temperature is measured 365 °C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 °C to 255 °C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chul Jin; Choi, Hyo Hyun [Department of Mechanical Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Sohn, Chae Hoon, E-mail: chsohn@sejong.ac.kr [Department of Mechanical Engineering, Sejong University, Seoul 143-747 (Korea, Republic of)

    2011-01-15

    Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 deg. C. First, its auto-ignition temperature is measured 365 deg. C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 deg. C to 255 deg. C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.

  8. Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner

    International Nuclear Information System (INIS)

    Kim, Chul Jin; Choi, Hyo Hyun; Sohn, Chae Hoon

    2011-01-01

    Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 deg. C. First, its auto-ignition temperature is measured 365 deg. C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 deg. C to 255 deg. C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.

  9. Equilibrium Droplets on Deformable Substrates: Equilibrium Conditions.

    Science.gov (United States)

    Koursari, Nektaria; Ahmed, Gulraiz; Starov, Victor M

    2018-05-15

    Equilibrium conditions of droplets on deformable substrates are investigated, and it is proven using Jacobi's sufficient condition that the obtained solutions really provide equilibrium profiles of both the droplet and the deformed support. At the equilibrium, the excess free energy of the system should have a minimum value, which means that both necessary and sufficient conditions of the minimum should be fulfilled. Only in this case, the obtained profiles provide the minimum of the excess free energy. The necessary condition of the equilibrium means that the first variation of the excess free energy should vanish, and the second variation should be positive. Unfortunately, the mentioned two conditions are not the proof that the obtained profiles correspond to the minimum of the excess free energy and they could not be. It is necessary to check whether the sufficient condition of the equilibrium (Jacobi's condition) is satisfied. To the best of our knowledge Jacobi's condition has never been verified for any already published equilibrium profiles of both the droplet and the deformable substrate. A simple model of the equilibrium droplet on the deformable substrate is considered, and it is shown that the deduced profiles of the equilibrium droplet and deformable substrate satisfy the Jacobi's condition, that is, really provide the minimum to the excess free energy of the system. To simplify calculations, a simplified linear disjoining/conjoining pressure isotherm is adopted for the calculations. It is shown that both necessary and sufficient conditions for equilibrium are satisfied. For the first time, validity of the Jacobi's condition is verified. The latter proves that the developed model really provides (i) the minimum of the excess free energy of the system droplet/deformable substrate and (ii) equilibrium profiles of both the droplet and the deformable substrate.

  10. Tribology of the lubricant quantized sliding state.

    Science.gov (United States)

    Castelli, Ivano Eligio; Capozza, Rosario; Vanossi, Andrea; Santoro, Giuseppe E; Manini, Nicola; Tosatti, Erio

    2009-11-07

    In the framework of Langevin dynamics, we demonstrate clear evidence of the peculiar quantized sliding state, previously found in a simple one-dimensional boundary lubricated model [A. Vanossi et al., Phys. Rev. Lett. 97, 056101 (2006)], for a substantially less idealized two-dimensional description of a confined multilayer solid lubricant under shear. This dynamical state, marked by a nontrivial "quantized" ratio of the averaged lubricant center-of-mass velocity to the externally imposed sliding speed, is recovered, and shown to be robust against the effects of thermal fluctuations, quenched disorder in the confining substrates, and over a wide range of loading forces. The lubricant softness, setting the width of the propagating solitonic structures, is found to play a major role in promoting in-registry commensurate regions beneficial to this quantized sliding. By evaluating the force instantaneously exerted on the top plate, we find that this quantized sliding represents a dynamical "pinned" state, characterized by significantly low values of the kinetic friction. While the quantized sliding occurs due to solitons being driven gently, the transition to ordinary unpinned sliding regimes can involve lubricant melting due to large shear-induced Joule heating, for example at large speed.

  11. Nanoscale Organic−Inorganic Hybrid Lubricants

    KAUST Repository

    Kim, Daniel

    2011-03-15

    Silica (SiO2) nanoparticles densely grafted with amphiphilic organic chains are used to create a family of organic-inorganic hybrid lubricants. Short sulfonate-functionalized alkylaryl chains covalently tethered to the particles form a dense corona brush that stabilizes them against aggregation. When these hybrid particles are dispersed in poly-α-olefin (PAO) oligomers, they form homogeneous nanocomposite fluids at both low and high particle loadings. By varying the volume fraction of the SiO2 nanostructures in the PAO nanocomposites, we show that exceptionally stable hybrid lubricants can be created and that their mechanical properties can be tuned to span the spectrum from simple liquids to complex gels. We further show that these hybrid lubricants simultaneously exhibit lower interfacial friction coefficients, enhanced wear and mechanical properties, and superior thermal stability in comparison with either PAO or its nanocomposites created at low nanoparticle loadings. Profilometry and energy dispersive X-ray spectroscopic analysis of the wear track show that the enhanced wear characteristics in PAO-SiO2 composite lubricants originate from two sources: localization of the SiO2 particles into the wear track and extension of the elastohydrodynamic lubrication regime to Sommerfeld numbers more than an order of magnitude larger than for PAO. © 2011 American Chemical Society.

  12. A strictly hyperbolic equilibrium phase transition model

    International Nuclear Information System (INIS)

    Allaire, G; Faccanoni, G; Kokh, S.

    2007-01-01

    This Note is concerned with the strict hyperbolicity of the compressible Euler equations equipped with an equation of state that describes the thermodynamical equilibrium between the liquid phase and the vapor phase of a fluid. The proof is valid for a very wide class of fluids. The argument only relies on smoothness assumptions and on the classical thermodynamical stability assumptions, that requires a definite negative Hessian matrix for each phase entropy as a function of the specific volume and internal energy. (authors)

  13. Vaporization of Samarium trichloride studied by thermogravimetry

    International Nuclear Information System (INIS)

    Esquivel, Marcelo R.; Pasquevich, Daniel M.

    2003-01-01

    In the present work, the vaporization reaction of SmCl 3 (l) obtained from the 'in situ' reaction of Sm 2 O 3 (s) and Cl 2 (g)-C(s) was studied by thermogravimetry under controlled atmosphere. The effects of both the temperature between 825 C degrees and 950 C degrees and the total flow gas on the vaporization rate of the following reaction: SmCl 3 (l) = SmCl 3 (g) were analyzed. The vaporization rate of the process was found to be independent of then total gas flow rate and highly dependent on the temperature. E ap calculation led to a value of 240 ± 10 kJ.mol -1 . A comparison between this value and that of the molar enthalpy of vaporization allow to the conclusion that the reaction occur in conditions near to equilibrium. The SmCl 3 identity was determined by X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). (author)

  14. Biomimetics in materials science self-healing, self-lubricating, and self-cleaning materials

    CERN Document Server

    Nosonovsky, Michael

    2012-01-01

    Biomimetics in Materials Science provides a comprehensive theoretical and practical review of biomimetic materials with self-healing, self-lubricating and self-cleaning properties. These three topics are closely related and constitute rapidly developing areas of study. The field of self-healing materials requires a new conceptual understanding of this biomimetic technology, which is in contrast to traditional  engineering processes such as wear and fatigue.  Biomimetics in Materials Science is the first monograph to be devoted to these materials. A new theoretical framework for these processes is presented based on the concept of multi-scale structure of entropy and non-equilibrium thermodynamics, together with a detailed review of the available technology. The latter includes experimental, modeling, and simulation results obtained on self-healing/lubricating/cleaning materials since their emergence in the past decade. Describes smart, biomimetic materials in the context of nanotechnology, biotechnology, an...

  15. Mechanics of a gaseous film barrier to lubricant wetting of elastohydrodynamically lubricated conjunctions

    Science.gov (United States)

    Prahl, J. M.; Hamrock, B. J.

    1985-01-01

    Two analytical models, one based on simple hydrodynamic lubrication and the other on soft elastohydrodynamic lubrication, are presented and compared to delineate the dominant physical parameters that govern the mechanics of a gaseous film between a small droplet of lubricant and the outer race of a ball bearing. Both models are based on the balance of gravity forces, air drag forces, and air film lubrication forces and incorporate a drag coefficient C sub D and a lubrication coefficient C sub L to be determined from experiment. The soft elastohydrodynamic lubrication (EHL) model considers the effects of droplet deformation and solid-surface geometry; the simpler hydrodynamic lubrication (HL) model assumes that the droplet remains essentially spherical. The droplet's angular position depended primarily on the ratio of gas inertia to droplet gravity forces and on the gas Reynolds number and weakly on the ratio of droplet gravity forces to surface tension forces (Bond number) and geometric ratios for the soft EHL. An experimental configuration in which an oil droplet is supported by an air film on the rotating outer race of a ball bearing within a pressure-controlled chamber produced measurements of droplet angular position as a function of outer-race velocity droplet size and type, and chamber pressure.

  16. Lubricated immersed boundary method in two dimensions

    Science.gov (United States)

    Fai, Thomas G.; Rycroft, Chris H.

    2018-03-01

    Many biological examples of fluid-structure interaction, including the transit of red blood cells through the narrow slits in the spleen and the intracellular trafficking of vesicles into dendritic spines, involve the near-contact of elastic structures separated by thin layers of fluid. Motivated by such problems, we introduce an immersed boundary method that uses elements of lubrication theory to resolve thin fluid layers between immersed boundaries. We demonstrate 2nd-order accurate convergence for simple two-dimensional flows with known exact solutions to showcase the increased accuracy of this method compared to the standard immersed boundary method. Motivated by the phenomenon of wall-induced migration, we apply the lubricated immersed boundary method to simulate an elastic vesicle near a wall in shear flow. We also simulate the dynamics of a vesicle traveling through a narrow channel and observe the ability of the lubricated method to capture the vesicle motion on relatively coarse fluid grids.

  17. Additives for high-temperature liquid lubricants

    Science.gov (United States)

    Lawton, Emil A.; Yavrouian, Andre H.; Repar, John

    1988-01-01

    A preliminary research program was conducted to demonstrate a new concept for additives to liquid lubricants. It was demonstrated that suspensions of o-phthalonitrile and a substituted 1,2-maleonitrile in mineral oil and dilute solutions of o-phthalonitrile and tetrafluoro-o-phthalonitrile extended the lifetime of bearings under boundary lubricating conditions. The solutions exhibited coefficients of friction under high loads of 0.02-0.03. These results were consistent with the hypothesis that these compounds react with the hot metal surface to form a planar lubricating film by means of a metal or metal oxide template reaction. Also, the adherence was very strong due to the chelating action of the planar macrocycles postulated to form under the experimental conditions.

  18. Compatibility of refrigerants and lubricants with elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Hamed, G.R.; Seiple, R.H.

    1993-01-01

    The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on availability of additional R-32. Swell behavior in the fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  19. Measurement and analysis of transient vaporization in oxide fuel materials

    International Nuclear Information System (INIS)

    Gorham-Bergeron, E.; Benson, D.A.

    1978-01-01

    A series of experiments is described in which samples are heated to produce high vapor pressure states in times of 10 -6 to 10 -3 seconds. Experimental measurements of vapor pressures over fresh UO 2 from the pulsed electron beam and pulsed reactor heating tests are presented and compared with other high temperature data. The interpretation of the vapor pressures measured in the tests is discussed in detail. Effects of original sample stoichiometry, chemical interactions with the container and non-equilibrium evaporation due to induced temperature gradients are discussed. Special attention is given to dynamic behavior in rapid heating and vaporization of the oxide due to chemical nonequilibrium. Finally, similar projected reactor experiments on irradiated fuel are described and vapor pressure predictions made using available equilibrium models. A discussion of information accessible from such future tests and its importance is presented

  20. Ion exchange equilibrium constants

    CERN Document Server

    Marcus, Y

    2013-01-01

    Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and

  1. Quantity Constrained General Equilibrium

    NARCIS (Netherlands)

    Babenko, R.; Talman, A.J.J.

    2006-01-01

    In a standard general equilibrium model it is assumed that there are no price restrictions and that prices adjust infinitely fast to their equilibrium values.In case of price restrictions a general equilibrium may not exist and rationing on net demands or supplies is needed to clear the markets.In

  2. Tolerance Optimization for Mechanisms with Lubricated Joints

    International Nuclear Information System (INIS)

    Choi, J.-H.; Lee, S.J.; Choi, D.-H.

    1998-01-01

    This paper addresses an analytical approach to tolerance optimization for planar mechanisms with lubricated joints based on mechanical error analysis. The mobility method is applied to consider the lubrication effects at joints and planar mechanisms are stochastically defined by using the clearance vector model for mechanical error analysis. The uncertainties considered in the analysis are tolerances on link lengths and radial clearances and these are selected as design variables. To show the validity of the proposed method for mechanical error analysis, it is applied to two examples, and the results obtained are compared with those of Monte Carlo simulations. Based on the mechanical error analysis, tolerance optimizations are applied to the examples

  3. The liquid to vapor phase transition in excited nuclei

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-05-08

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

  4. Development and efficiency assessment of process lubrication for hot forging

    Science.gov (United States)

    Kargin, S.; Artyukh, Viktor; Ignatovich, I.; Dikareva, Varvara

    2017-10-01

    The article considers innovative technologies in testing and production of process lubricants for hot bulk forging. There were developed new compositions of eco-friendly water-graphite process lubricants for hot extrusion and forging. New approaches to efficiency assessment of process lubricants are developed and described in the following article. Laboratory and field results are presented.

  5. Deposited Micro Porous Layer as Lubricant Carrier in Metal Forming

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Bay, Niels; Tang, Peter Torben

    2008-01-01

    as lubricant reservoirs. Conventional friction tests for cold forming; ring compression and double cup extrusion tests are carried out with Molykote DX paste and mineral oil as lubricant. Both lubricants act as intended for the ring compressions test whereas only the low viscosity oil perform successfully...... in the cup extrusion test. For all specimens without the porous coating, high friction conditions are identified....

  6. FY2014 Fuel & Lubricant Technologies Annual Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Stork, Kevin [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2016-02-01

    Annual progress report for Fuel & Lubricant Technologies. The Fuel & Lubricant Technologies Program supports fuels and lubricants research and development (R&D) to provide vehicle manufacturers and users with cost-competitive options that enable high fuel economy with low emissions, and contribute to petroleum displacement.

  7. Developments of New Lubricants for Cold Forging of Stainless Steel

    DEFF Research Database (Denmark)

    Steenberg, Thomas; Christensen, Erik; Olesen, P.

    1997-01-01

    Two new lubricant systems for cold forging of stainless steel have been developed. The main component of these systems are FeCl3 and ZnCa2(PO4)2, respectively. Both lubricant systems have been tested using a backward extrusion test. The results show excellent lubricating properties with respect...

  8. Dimers in nucleating vapors

    Science.gov (United States)

    Lushnikov, A. A.; Kulmala, M.

    1998-09-01

    The dimer stage of nucleation may affect considerably the rate of the nucleation process at high supersaturation of the nucleating vapor. Assuming that the dimer formation limits the nucleation rate, the kinetics of the particle formation-growth process is studied starting with the definition of dimers as bound states of two associating molecules. The partition function of dimer states is calculated by summing the Boltzmann factor over all classical bound states, and the equilibrium population of dimers is found for two types of intermolecular forces: the Lennard-Jones (LJ) and rectangular well+hard core (RW) potentials. The principle of detailed balance is used for calculating the evaporation rate of dimers. The kinetics of the particle formation-growth process is then investigated under the assumption that the trimers are stable with respect to evaporation and that the condensation rate is a power function of the particle mass. If the power exponent λ=n/(n+1) (n is a non-negative integer), the kinetics of the process is described by a finite set of moments of particle mass distribution. When the characteristic time of the particle formation by nucleation is much shorter than that of the condensational growth, n+2 universal functions of a nondimensional time define the kinetic process. These functions are calculated for λ=2/3 (gas-to-particle conversion in the free molecular regime) and λ=1/2 (formation of islands on surfaces).

  9. Tribology: Friction, lubrication, and wear technology

    Science.gov (United States)

    Blau, Peter J.

    1993-01-01

    The topics are presented in viewgraph form and include the following: introduction and definitions of terms; friction concepts; lubrication technology concepts; wear technology concepts; and tribological transitions. This document is designed for educators who seek to teach these concepts to their students.

  10. Physicochemical properties and lubricant potentials of Blighia ...

    African Journals Online (AJOL)

    Fatty acid methyl ester analysis (FAME) revealed 96.89 % of monounsaturated fatty acids and esters in the range ... uniformity, hardness, disintegration and dissolution characteristics. Conclusion: Blighia sapida seed oil is a potentially useful low-cost tablet lubricant. However ... Products derived from plants sources can be ...

  11. A Review of Ionic Liquid Lubricants

    Directory of Open Access Journals (Sweden)

    Anthony E. Somers

    2013-01-01

    Full Text Available Due to ever increasing demands on lubricants, such as increased service intervals, reduced volumes and reduced emissions, there is a need to develop new lubricants and improved wear additives. Ionic liquids (ILs are room temperature molten salts that have recently been shown to offer many advantages in this area. The application of ILs as lubricants in a diverse range of systems has found that these materials can show remarkable protection against wear and significantly reduce friction in the neat state. Recently, some researchers have shown that a small family of ILs can also be incorporated into non-polar base oils, replacing traditional anti-wear additives, with excellent performance of the neat IL being maintained. ILs consist of large asymmetrical ions that may readily adsorb onto a metal surface and produce a thin, protective film under boundary lubrication conditions. Under extreme pressure conditions, certain IL compounds can also react to form a protective tribofilm, in particular when fluorine, phosphorus or boron atoms are present in the constituent ions.

  12. On the lubrication of mechanical face seals

    NARCIS (Netherlands)

    Lubbinge, H.

    1999-01-01

    Hence, in this thesis, a model is presented which is able to calculate a complete Stribeck curve for a mechanical face seal and, as a consequence, the transition from full film to mixed lubrication as a function of the operational conditions. This model is based on a combination of a contact model

  13. Self-lubricating fluid bearing assembly

    International Nuclear Information System (INIS)

    Kapich, D.D.

    1981-01-01

    A sealed self-lubricating fluid bearing assembly is described for circulating fluid in the form of a gas coolant in a nuclear reactor, the power for the circulator being provided by a shaft located within the primary containment vessel. In such a system the reactor coolant is isolated from the fluid region at the far end of the drive shaft. (U.K.)

  14. A quantitative lubricant test for deep drawing

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan L.

    2010-01-01

    A tribological test for deep drawing has been developed by which the performance of lubricants may be evaluated quantitatively measuring the maximum backstroke force on the punch owing to friction between tool and workpiece surface. The forming force is found not to give useful information...

  15. Thermo-hydrodynamic lubrication in hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the thermo-hydrodynamic and the thermo-elasto-hydrodynamic lubrication. The algorithms are methodically detailed and each section is thoroughly illustrated.

  16. Self-lubricating fluorine shaft seal material

    Science.gov (United States)

    Munk, W. R.

    1970-01-01

    Lubricating film is produced by a reaction of fluorine with a composite of aluminum oxide and nickel powder. The rate of nickel fluoride generation is proportional to the rate at which the fluoride is rubbed off the surface, allowing the seal to operate with the lowest possible heating.

  17. Formulation of lubricating grease using Beeswax thickener

    Science.gov (United States)

    Suhaila, N.; Japar, A.; Aizudin, M.; Aziz, A.; Najib Razali, Mohd

    2018-04-01

    The issues on environmental pollution has brought the industries to seek the alternative green solutions for lubricating grease formulation. The significant challenges in producing modified grease are in which considering the chosen thickener as one of the environmental friendly material. The main purposes of the current research were to formulate lubricant grease using different types of base oils and to study the effect of thickener on the formulated lubricant grease. Used oil and motor oil were used as the base oils for the grease preparation. Beeswax and Damar were used as thickener and additive. The grease is tested based on its consistency, stability and oil bleeding. The prepared greases achieved grease consistency of grade 2 and 3 except for grease with unfiltered used oil. Grease formulated with used oil and synthetic oil tend to harden and loss its lubricating ability under high temperature compared to motor oil’ grease. Grease modification using environmental friendly thickener were successfully formulated but it is considered as a low temperature grease as the beeswax have low melting point of 62°C-65°C.

  18. Exploring Low Emission Lubricants for Diesel Engines

    Energy Technology Data Exchange (ETDEWEB)

    Perez, J. M.

    2000-07-06

    A workshop to explore the technological issues involved with the removal of sulfur from lubricants and the development of low emission diesel engine oils was held in Scottsdale, Arizona, January 30 through February 1, 2000. It presented an overview of the current technology by means of panel discussions and technical presentations from industry, government, and academia.

  19. The Lubrication Qualities of Dimethyl Ether (DME)

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Sorenson, Spencer C; Jakobsen, J.

    2002-01-01

    by mixing the DME with reasonable amounts of additives. The main conclusion drawn from these measurements is that a combination of lubricity and viscosity comparable to one of diesel oil cannot be reached in the case of DME unless a huge amount of additive is used. This is not an attractive solution...

  20. The use of screening tests in spacecraft lubricant evaluation

    Science.gov (United States)

    Kalogeras, Chris; Hilton, Mike; Carre, David; Didziulis, Stephen; Fleischauer, Paul

    1993-01-01

    A lubricant screening test fixture has been devised in order to satisfy the need to obtain lubricant performance data in a timely manner. This fixture has been used to perform short-term tests on potential lubricants for several spacecraft applications. The results of these tests have saved time by producing qualitative performance rankings of lubricant selections prior to life testing. To date, this test fixture has been used to test lubricants for 3 particular applications. The qualitative results from these tests have been verified by life test results and have provided insight into the function of various anti-wear additives.

  1. Study of PrP - I heterogeneous equilibrium

    International Nuclear Information System (INIS)

    Vasil'eva, I.G.; Mironov, K.E.; Tarasenko, A.D.

    1976-01-01

    Using static methods the authors have measured the equilibrium vapor pressure in the system PrP+I 2 at different temperatures and different initial iodine concentrations. The equilibrium reactions in the system have been determined. The reaction of PrP with iodine is irreversible. The content of PrI 3 and I 2 in the gas phase is negligible. The pressure in the system is determined by the partial pressure of phosphorus

  2. Vapor-liquid equilibrium in the In-P system

    International Nuclear Information System (INIS)

    Khukhryanskij, Yu.P.; Ermilin, V.N.

    1977-01-01

    The functional dependence of the pressure of the vapour phase over indium solutions of phosphorus in the range from 1023 to 1123 K was analyzed to elucidate the nature of these solutions. It was established that in dilute solutions the phosphorus is in the monatomic form and enters into the composition of ''associated complexes'' with the indium. Each complex is a space group of a variable number of In atoms surrounding the phosphorus atom. These complexes, taken together, ensure disordered distribution of the phosphorus in solution. The binding energy of the phosphorus in the complex is 62.56+-1.30 kcal/g-atom. The composition of the vapour phase over the solutions is considered

  3. Vapor-Liquid Equilibrium in Diluted Polymer plus Solvent Systems

    Czech Academy of Sciences Publication Activity Database

    Bogdanić, Grozdana; Wichterle, Ivan

    2011-01-01

    Roč. 56, č. 4 (2011), s. 1080-1083 ISSN 0021-9568 R&D Projects: GA ČR GA104/07/0444 Grant - others:MZOŠ(HR) 061-0000000-3029 Institutional research plan: CEZ:AV0Z40720504 Keywords : polymer * prediction * total pressure Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.693, year: 2011

  4. Phase equilibrium engineering

    CERN Document Server

    Brignole, Esteban Alberto

    2013-01-01

    Traditionally, the teaching of phase equilibria emphasizes the relationships between the thermodynamic variables of each phase in equilibrium rather than its engineering applications. This book changes the focus from the use of thermodynamics relationships to compute phase equilibria to the design and control of the phase conditions that a process needs. Phase Equilibrium Engineering presents a systematic study and application of phase equilibrium tools to the development of chemical processes. The thermodynamic modeling of mixtures for process development, synthesis, simulation, design and

  5. Equilibrium and generators

    International Nuclear Information System (INIS)

    Balter, H.S.

    1994-01-01

    This work studies the behaviour of radionuclides when it produce a desintegration activity,decay and the isotopes stable creation. It gives definitions about the equilibrium between activity of parent and activity of the daughter, radioactive decay,isotope stable and transient equilibrium and maxim activity time. Some considerations had been given to generators that permit a disgregation of two radioisotopes in equilibrium and its good performance. Tabs

  6. Hybrid Vapor Stripping-Vapor Permeation Process for Recovery and Dehydration of 1-Butanol and Acetone/Butanol/Ethanol from Dilute Aqueous Solutions. Part 1. Process Simulations

    Science.gov (United States)

    BACKGROUND: Fermentative production of butanol is limited to low concentrations, typically less than 2 wt% solvent, due to product inhibition. The result is high separation energy demand by conventional distillation approaches, despite favorable vapor-liquid equilibrium and parti...

  7. Importance Profiles for Water Vapor

    Science.gov (United States)

    Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita

    2017-11-01

    Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or "kernel" depends on whether specific humidity S, relative humidity R, or ln( R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

  8. USDOE Top-of-Rail Lubricant Project; FINAL

    International Nuclear Information System (INIS)

    Mohumad F. Alzoubi; George R. Fenske; Robert A. Erck; Amrit S. Boparai

    2002-01-01

    Lubrication of wheel/rail systems has been recognized for the last two decades as a very important issue for railroads. Energy savings and less friction and wear can be realized if a lubricant can be used at the wheel/rail interface. On the other hand, adverse influences are seen in operating and wear conditions if improper or excessive lubrication is used. Also, inefficiencies in lubrication need to be avoided for economic and environmental reasons. The top-of-rail (TOR) lubricant concept was developed by Texaco Corporation to lubricate wheels and rails effectively and efficiently. Tranergy Corporation has been developing its SENTRAEN 2000(trademark) lubrication system for the last ten years, and this revolutionary new high-tech on-board rail lubrication system promises to dramatically improve the energy efficiency, performance, safety, and track environment of railroads. The system is fully computer-controlled and ensures that all of the lubricant is consumed as the end of the train passes. Lubricant quantity dispensed is a function of grade, speed, curve, and axle load. Tranergy also has its LA4000(trademark) wheel and rail simulator, a lubrication and traction testing apparatus. The primary task of this project was collecting and analyzing the volatile and semivolatile compounds produced as the lubricant was used. The volatile organic compounds were collected by Carbotrap cartridges and analyzed by adsorption and gas chromatography/mass spectrometry (GC/MS). The semivolatile fraction was obtained by collecting liquid that dripped from the test wheel. The collected material was also analyzed by GC/MS. Both of these analyses were qualitative. The results indicated that in the volatile fraction, the only compounds on the Environmental Protection Agency's (EPA) Superfund List of Analytes detected were contaminants either in the room air or from other potential contamination sources in the laboratory. Similarly, in the semivolatile fraction none of the detected

  9. Lubricant effects on low Dk and silicone hydrogel lens comfort.

    Science.gov (United States)

    Ozkan, Jerome; Papas, Eric

    2008-08-01

    To investigate the influence of three lubricants of varying viscosity, on postinsertion and 6 h comfort with contact lens wear. Comfort and associated symptoms of dryness were assessed in 15 experienced contact lens wearers. Subjects wore a low Dk lens in one eye and a silicone hydrogel in the other and participated in four separate trials involving no lubricant (baseline), saline, and two commercially available lubricants of differing viscosity. The in-eye lubricants were used immediately following lens insertion and every 2 h postinsertion for a 6 h wear period. Postlens insertion comfort was significantly better for both lens types when lubricants or saline were used compared with no lubricant use. After 6 h lens wear, comfort was influenced by lens type and not by in-eye lubricant or saline use. Also after 6 h lens wear, less dryness sensation was reported for silicone hydrogel lenses when using lubricants but not saline. Although lubricant use does help reduce dryness symptoms with silicone hydrogel lens wear, there appears to be minimal longer-term benefit to comfort. Furthermore, increased lubricant viscosity did not lead to improved longer-term comfort.

  10. Fall Back Equilibrium

    NARCIS (Netherlands)

    Kleppe, J.; Borm, P.E.M.; Hendrickx, R.L.P.

    2008-01-01

    Fall back equilibrium is a refinement of the Nash equilibrium concept. In the underly- ing thought experiment each player faces the possibility that, after all players decided on their action, his chosen action turns out to be blocked. Therefore, each player has to decide beforehand on a back-up

  11. Noise of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2002-01-01

    The purpose of the paper is to provide a procedure to calculate the noise of oil lubricated journal bearings. To do this, the nonlinear transient analysis of rotor-bearing system including rotor imbalance is performed. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Furthermore, a transmission theory of plane waves on a boundary of the outer surface of the bearing is used to obtain the sound pressure level of the bearing. Results show that the sound pressure level of the bearing can be increased with the rotational speed of the rotor although the whirl amplitude of the rotor is decreased at high speed. Noise estimating procedures presented in this paper could be an aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  12. Electrotunable lubricity with ionic liquids: the influence of nanoscale roughness.

    Science.gov (United States)

    David, Alessio; Fajardo, Oscar Y; Kornyshev, Alexei A; Urbakh, Michael; Bresme, Fernando

    2017-07-01

    The properties of ionic liquids can be modified by applying an external electrostatic potential, providing a route to control their performance in nanolubrication applications. Most computational studies to date have focused on the investigation of smooth surfaces. Real surfaces are generally inhomogeneous and feature roughness of different length scales. We report here a study of the possible effects that surface roughness may have on electrotunable lubricity with ionic liquids, performed here by means of non-equilibrium molecular dynamics simulations. In order to advance our understanding of the interplay of friction and substrate structure we investigate coarse grained models of ionic liquids confined in model surfaces with nanometer roughness. The friction is shown to depend on the roughness of the substrate and the direction of shear. For the investigated systems, the friction coefficient is found to increase with roughness. These results are in contrast with previous studies, where roughness induced reduction of friction was reported, and they highlight the strong sensitivity of the friction process to the structure of the surfaces. The friction force features a maximum at a specific surface charge density. This behaviour is reminiscent of the one reported in ionic liquids confined by flat surfaces, showing the generality of this physical effect in confined ionic liquids. We find that an increase of the substrate-liquid dispersion interactions shifts the maximum to lower surface charges. This effect opens a route to control electrotunable friction phenomena by tuning both the electrostatic potential and the composition of the confining surfaces.

  13. Technology development for indigenous water lubricated bearings

    International Nuclear Information System (INIS)

    Limaye, P.K.; Soni, N.L.; Agrawal, R.G.

    2010-01-01

    Water Lubricated Bearings (WLB) are used in various mechanisms of fuel handling systems of PHWRs and AHWR. Availability and random failures of these bearings was a major factor in refuelling operations. Indigenous development of these bearings was taken up and 7 types of antifriction bearings in various sizes (totaling 37 variants) for PHWR, AHWR and Dhruva applications were successfully developed. This paper deals with various aspects of WLB development. (author)

  14. Universal water-dilutable inhibited protective lubricants

    International Nuclear Information System (INIS)

    Mamtseva, M.V.; Kardash, N.V.; Latynina, M.B.

    1993-01-01

    In the interest of environmental protection, improvement of working conditions, and reduced fire hazard in production operations, water-based protective lubricants are now available in a wide assortment, and the production volume has increased greatly. The term water-dilutable inhibited protective lubricants (WDIPL) means water-soluble, water-emulsifiable, or water-dispersible products with the dual function of reducing friction and wear and protecting metal surfaces against corrosion for specified periods of time. According to the standard Unified System of Protection Against Corrosion and Aging (COST 9.103-78), WDIPLs are classed as products for the temporary corrosion protection of metals and end-items. In the general class of WDIPLs one can identify water-dilutable combination corrosion inhibitors, film-forming inhibited petroleum compositions (FIPC-d), detergent-preservative fluids, operational-preservative lubricating-cooling process compounds (ICPC), and, finally, universal multifunctional products. Combined corrosion inhibitors may consist of water-soluble organic and inorganic compounds; water/oil and oil-soluble surfactants - corrosion inhibitors of the chemisorption type or donor and/or acceptor types; shielding inhibitors of the adsorption type; and fast-acting water-displacing components. 23 refs

  15. Adsorption of radon and water vapor on commercial activated carbons

    International Nuclear Information System (INIS)

    Hassan, N.M.; Ghosh, T.K.; Hines, A.L.; Loyalka, S.K.

    1995-01-01

    Equilibrium adsorption isotherms are reported for radon and water vapor on two commercial activated carbons: coconut shell Type PCB and hardwood Type BD. The isotherms of the water vapor were measured gravimetrically at 298 K. The isotherms of radon from dry nitrogen were obtained at 293, 298, and 308 K while the data for the mixture of radon and water vapor were measured at 298 K. The concentrations of radon in the gas and solid phases were measured simultaneously, once the adsorption equilibrium and the radioactive equilibrium between the radon and its daughter products were established. The shape of the isotherms was of Type III for the radon and Type V for the water vapor, according to Brunauer's classification. The adsorption mechanism was similar for both the radon and the water vapor, being physical adsorption on the macropore surface area in the low pressure region and micropore filling near saturation pressure. The uptake capacity of radon decreased both with increasing temperature and relative humidity. The heat of adsorption data indicated that the PCB- and the BD-activated carbons provided a heterogeneous surface for radon adsorption. The equilibrium data for radon were correlated with a modified Freundlich equation

  16. Development of a device to valuate the effect of ethanol on the vapor pressure and vaporization enthalpy of fuel gasolines

    OpenAIRE

    Cataluña, Renato; Silva, Rosângela

    2006-01-01

    The quality of the gasoline utilized for fueling internal combustion engines with spark ignition is directly affected by the gasoline's properties. Thus, the fuel's properties must be in perfect equilibrium to allow the engine to perform optimally, not only insofar as fuel consumption is concerned, but also in order to reduce the emission of pollutants. Vapor pressure and vaporization enthalpy are important properties of a gasoline determining the fuel's behavior under different operating con...

  17. Molecular dynamics simulations of elasto-hydrodynamic lubrication and boundary lubrication for automotive tribology

    International Nuclear Information System (INIS)

    Washizu, Hitoshi; Sanda, Shuzo; Hyodo, Shi-aki; Ohmori, Toshihide; Nishino, Noriaki; Suzuki, Atsushi

    2007-01-01

    Friction control of machine elements on a molecular level is a challenging subject in vehicle technology. We describe the molecular dynamics studies of friction in two significant lubrication regimes. As a case of elastohydrodynamic lubrication, we introduce the mechanism of momentum transfer related to the molecular structure of the hydrocarbon fluids, phase transition of the fluids under high pressure, and a submicron thickness simulation of the oil film using a tera-flops computer. For boundary lubrication, the dynamic behavior of water molecules on hydrophilic and hydrophobic silicon surfaces under a shear condition is studied. The dynamic structure of the hydrogen bond network on the hydrophilic surface is related to the low friction of the diamond-like carbon containing silicon (DLC-Si) coating

  18. Lubricant flow analysis for effective lubrication of tractor forward/reverse clutch

    Directory of Open Access Journals (Sweden)

    Daekyung Noh

    2017-04-01

    Full Text Available Owing to the high power requirements of tractors, their low-power transmission gears often experience durability problems such as burning of the clutch. The operation of tractors under high load conditions also causes clutch slip, with the consequent longer operation duration exacerbating the burning of the friction plate. Solving this problem requires effective lubricant distribution. This was achieved in the present study by the development of an analysis model for predicting the lubricant flow rate. The reliability of the model was verified by comparing its predictions for various operation conditions with experimental measurements. Using the model, it was determined that effective distribution of the lubricant could be achieved without significant modification of the system, by only adjusting the gaps between the clutch piston and the housing, and between the separation plates and the case. Keywords: Mechanical engineering

  19. Chemical Principles Revisited: Chemical Equilibrium.

    Science.gov (United States)

    Mickey, Charles D.

    1980-01-01

    Describes: (1) Law of Mass Action; (2) equilibrium constant and ideal behavior; (3) general form of the equilibrium constant; (4) forward and reverse reactions; (5) factors influencing equilibrium; (6) Le Chatelier's principle; (7) effects of temperature, changing concentration, and pressure on equilibrium; and (8) catalysts and equilibrium. (JN)

  20. Some Examples of Formation of Shells and Their Role in Establishment of Equilibrium

    Science.gov (United States)

    Koutandos, Spyridon

    2012-01-01

    In this article we discuss the concept of equilibrium establishment in four most usual instances as is electrostriction and vaporization as related to the concept of equilibrium shell formation. Two more cases are then studied which are of relevance. One is the Brownian movement, the study of which is essential for pedagogical reasons as to…

  1. Equilibrium and non-equilibrium phenomena in arcs and torches

    NARCIS (Netherlands)

    Mullen, van der J.J.A.M.

    2000-01-01

    A general treatment of non-equilibrium plasma aspects is obtained by relating transport fluxes to equilibrium restoring processes in so-called disturbed Bilateral Relations. The (non) equilibrium stage of a small microwave induced plasma serves as case study.

  2. Hot nuclear matter and thermodynamical equilibrium

    International Nuclear Information System (INIS)

    Borderie, B.; Bacri, C.O.; Dore, D.; Frankland, J.D.; Plagnol, E.; Rivet, M.F.; Tassan-Got, L.

    1999-01-01

    Quasi-complete events from collisions between 36 Ar and 58 Ni corresponding to vaporized sources have been detected with the multidetector INDRA over the excitation energy range 10 - 28 AMeV. For the first time complete information concerning kinematical properties of emitted particles and chemical composition (mean values but also variances) are derived. Despite the very extreme conditions in which such sources are produced (binary collisions with short reaction times and source life-times), their properties are in agreement with the results of a statistical model including a final state excluded volume interaction and describing a gas of fermions and bosons in thermodynamical equilibrium. (authors)

  3. Molecular dynamics study of lubricant depletion by pulsed laser heating

    Science.gov (United States)

    Seo, Young Woo; Rosenkranz, Andreas; Talke, Frank E.

    2018-05-01

    In this study, molecular dynamics simulations were performed to numerically investigate the effect of pulsed laser heating on lubricant depletion. The maximum temperature, the lubricant depletion width, the number of evaporated lubricant beads and the number of fragmented lubricant chains were studied as a function of laser peak power, pulse duration and repetition rate. A continuous-wave laser and a square pulse laser were simulated and compared to a Gaussian pulse laser. With increasing repetition rate, pulsed laser heating was found to approach continuous-wave laser heating.

  4. Effect of gamma radiation on graphite - PTFE dry lubrication system

    Science.gov (United States)

    Singh, Sachin; Tyagi, Mukti; Seshadri, Geetha; Tyagi, Ajay Kumar; Varshney, Lalit

    2017-12-01

    An effect of gamma radiation on lubrication behavior of graphite -PTFE dry lubrication system has been studied using (TR-TW-30L) tribometer with thrust washer attachment in plane contact. Different compositions of graphite and PTFE were prepared and irradiated by gamma rays. Gamma radiation exposure significantly improves the tribological properties indicated by decrease in coefficient of friction and wear properties of graphite -PTFE dry lubrication system. SEM and XRD analysis confirm the physico-chemical modification of graphite-PTFE on gamma radiation exposure leading to a novel dry lubrication system with good slip and anti friction properties.

  5. Vapor pressure and thermodynamics of beryllium carbide

    International Nuclear Information System (INIS)

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

    1980-01-01

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

  6. Non-equilibrium Economics

    Directory of Open Access Journals (Sweden)

    Katalin Martinás

    2007-02-01

    Full Text Available A microeconomic, agent based framework to dynamic economics is formulated in a materialist approach. An axiomatic foundation of a non-equilibrium microeconomics is outlined. Economic activity is modelled as transformation and transport of commodities (materials owned by the agents. Rate of transformations (production intensity, and the rate of transport (trade are defined by the agents. Economic decision rules are derived from the observed economic behaviour. The non-linear equations are solved numerically for a model economy. Numerical solutions for simple model economies suggest that the some of the results of general equilibrium economics are consequences only of the equilibrium hypothesis. We show that perfect competition of selfish agents does not guarantee the stability of economic equilibrium, but cooperativity is needed, too.

  7. DIAGNOSIS OF FINANCIAL EQUILIBRIUM

    Directory of Open Access Journals (Sweden)

    SUCIU GHEORGHE

    2013-04-01

    Full Text Available The analysis based on the balance sheet tries to identify the state of equilibrium (disequilibrium that exists in a company. The easiest way to determine the state of equilibrium is by looking at the balance sheet and at the information it offers. Because in the balance sheet there are elements that do not reflect their real value, the one established on the market, they must be readjusted, and those elements which are not related to the ordinary operating activities must be eliminated. The diagnosis of financial equilibrium takes into account 2 components: financing sources (ownership equity, loaned, temporarily attracted. An efficient financial equilibrium must respect 2 fundamental requirements: permanent sources represented by ownership equity and loans for more than 1 year should finance permanent needs, and temporary resources should finance the operating cycle.

  8. Toxicity of vapor phase petroleum contaminants to microbial degrader communities

    International Nuclear Information System (INIS)

    Long, S.C.; Davey, C.A.

    1994-01-01

    Petroleum products constitute the largest quantity of synthetic organic chemical products produced in the US. They are comprised of mostly hydrocarbon constituents from many different chemical classes including alkenes, cycloalkanes, aromatic compounds, and polyaromatic hydrocarbons. Many petroleum constituents are classified as volatile organic compounds or VOCs. Petroleum products also constitute a major portion of environmental pollution. One emerging technology, with promise for applications to VOCs in subsurface soil environments, is bioventing coupled with soil vapor extraction. These technologies involve volatilization of contaminants into the soil gas phase by injection and withdrawal of air. This air movement causes enhancement of the aerobic microbial degradation of the mobilized vapors by the indigenous populations. This study investigated the effects of exposure of mixed, subsurface microbial communities to vapor phase petroleum constituents or vapors of petroleum mixtures. Soil slurries were prepared and plated onto mineral salts agar plates and exposed to vapor phase contaminants at equilibrium with pure product. Representative n-alkane, branched alkane, cycloalkane, and aromatic compounds were tested as well as petroleum product mixtures. Vapor exposure altered the numbers and morphologies of the colonies enumerated when compared to controls. However, even at high, equilibrium vapor concentrations, microbial degrader populations were not completely inhibited

  9. Full Life Wind Turbine Gearbox Lubricating Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, Glenn A.; Jungk, Manfred; Bryant, Jonathan J.; Lauer, Rebecca S.; Chobot, Anthony; Mayer, Tyler; Palmer, Shane; Kauffman, Robert E.

    2012-02-28

    Industrial gear box lubricants typically are hydrocarbon based mineral oils with considerable amounts of additives to overcome the lack of base fluid properties like wear protection, oxidation stability, load carrying capacity, low temperature solidification and drop of viscosity at higher temperatures. For today's wind turbine gearboxes, the requirements are more severe and synthetic hydrocarbon oils are used to improve on this, but all such hydrocarbon based lubricants require significant amounts of Extreme Pressure (EP) additives to meet performance requirements. Perfluoropolyether (PFPE) fluids provide load carrying capacity as an inherent property. During the course of the project with the main tasks of 'Establish a Benchmark', 'Lubricant Evaluation', 'Full Scale Gearbox Trial' and 'Economic Evaluation', the PAO Reference oil exhibited significant changes after laboratory gear testing, in service operation in the field and full scale gearbox trial. Four hydrocarbon base oils were selected for comparison in the benchmarking exercise and showed variation with respect to meeting the requirements for the laboratory micro-pitting tests, while the PFPE fluid exceeded the requirements even with the material taken after the full scale gear box trial. This is remarkable for a lubricant without EP additives. Laboratory bearing tests performed on the PFPE fluids before and after the full scale gear box trial showed the results met requirements for the industry standard. The PFPE fluid successfully completed the full scale gear box test program which included baseline and progressive staged load testing. The evaluation of gears showed no micro-pitting or objectionable wear. By the final stage, lubricant film thickness had been reduced to just 21% of its original value, this was by design and resulted in a lambda ratio of well below 1. This test design scenario of a low lambda ratio is a very undesirable lubrication condition

  10. Equilibrium statistical mechanics

    CERN Document Server

    Mayer, J E

    1968-01-01

    The International Encyclopedia of Physical Chemistry and Chemical Physics, Volume 1: Equilibrium Statistical Mechanics covers the fundamental principles and the development of theoretical aspects of equilibrium statistical mechanics. Statistical mechanical is the study of the connection between the macroscopic behavior of bulk matter and the microscopic properties of its constituent atoms and molecules. This book contains eight chapters, and begins with a presentation of the master equation used for the calculation of the fundamental thermodynamic functions. The succeeding chapters highlight t

  11. Computing Equilibrium Chemical Compositions

    Science.gov (United States)

    Mcbride, Bonnie J.; Gordon, Sanford

    1995-01-01

    Chemical Equilibrium With Transport Properties, 1993 (CET93) computer program provides data on chemical-equilibrium compositions. Aids calculation of thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93/PC is version of CET93 specifically designed to run within 640K memory limit of MS-DOS operating system. CET93/PC written in FORTRAN.

  12. Influences of lubricant pocket geometry and working conditions upon micro lubrication mechanisms in upsetting and strip drawing

    DEFF Research Database (Denmark)

    Shimizu, Ichiro; Martins, P. A. F.; Bay, Niels

    2010-01-01

    , during upsetting and strip drawing, by means of a rigid-viscoplastic finite-element formulation. Special emphasis is placed on the effect of pocket geometry on the build-up of hydrostatic pressure, which is responsible for the onset of micro-lubrication mechanisms. A good agreement is found between......Micro-lubricant pockets located in the surface of plastically deforming workpieces are recognised to improve the performance of fluid lubrication in a metal-forming process. This work investigates the joint influence of pocket geometry and process working conditions on micro-lubrication mechanisms...

  13. Ultralow Friction Self-Lubricating Nanocomposites with Mesoporous Metal-Organic Frameworks as Smart Nanocontainers for Lubricants.

    Science.gov (United States)

    Zhang, Guoliang; Xie, Guoxin; Si, Lina; Wen, Shizhu; Guo, Dan

    2017-11-01

    Smart nanocontainers with stimuli-responsive property can be used to fabricate a new kind of self-lubricating nanocomposite, while the practical potential of the metal-organic frameworks (MOFs) as nanocontainers for lubricants has not been realized. In this work, mesoporous Cu-BTC MOFs storing oleylamine nanocomposites were explored from synthesis and microstructure to self-lubricating characterization. The stress stimuli-responsiveness behavior of the Cu-BTC storing oleylamine (Cu-BTCO) for lubrication has been investigated by subjecting it to macroscopic ball-on-disc friction tests. The steady-state coefficients of friction (COFs) of the Cu-BTC nanocomposites without lubricants were ca. 0.5. In contrast, after oleylamine as the lubricant was incorporated into the Cu-BTC container in the nanocomposite, ultralow friction (COF, ca. 0.03) was achieved. It has been demonstrated that the improved lubricating performance was associated with the lubricating film which was in situ produced by the chemical reaction between the oleylamine released from the nanocontainer and the friction pairs. Therefore, the nanocomposite with smart Cu-BTC container holds the promise of realizing extraordinary self-lubricating properties under stress stimuli.

  14. Fuel vapor pressure (FVAPRS)

    International Nuclear Information System (INIS)

    Mason, R.E.

    1979-04-01

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

  15. Two methodologies for optical analysis of contaminated engine lubricants

    International Nuclear Information System (INIS)

    Aghayan, Hamid; Yang, Jun; Bordatchev, Evgueni

    2012-01-01

    The performance, efficiency and lifetime of modern combustion engines significantly depend on the quality of the engine lubricants. However, contaminants, such as gasoline, moisture, coolant and wear particles, reduce the life of engine mechanical components and lubricant quality. Therefore, direct and indirect measurements of engine lubricant properties, such as physical-mechanical, electro-magnetic, chemical and optical properties, are intensively utilized in engine condition monitoring systems and sensors developed within the last decade. Such sensors for the measurement of engine lubricant properties can be used to detect a functional limit of the in-use lubricant, increase drain interval and reduce the environmental impact. This paper proposes two new methodologies for the quantitative and qualitative analysis of the presence of contaminants in the engine lubricants. The methodologies are based on optical analysis of the distortion effect when an object image is obtained through a thin random optical medium (e.g. engine lubricant). The novelty of the proposed methodologies is in the introduction of an object with a known periodic shape behind a thin film of the contaminated lubricant. In this case, an acquired image represents a combined lubricant–object optical appearance, where an a priori known periodic structure of the object is distorted by a contaminated lubricant. In the object shape-based optical analysis, several parameters of an acquired optical image, such as the gray scale intensity of lubricant and object, shape width at object and lubricant levels, object relative intensity and width non-uniformity coefficient are newly proposed. Variations in the contaminant concentration and use of different contaminants lead to the changes of these parameters measured on-line. In the statistical optical analysis methodology, statistical auto- and cross-characteristics (e.g. auto- and cross-correlation functions, auto- and cross-spectrums, transfer function

  16. Role of water lubricated bearings in Candu reactors

    International Nuclear Information System (INIS)

    Kumar, Ashok N.

    1999-01-01

    During the twentieth century a great emphasis was placed in understanding and defining the operating regime of oil and grease lubricated components. Major advances have been made through elastohydrodynamic lubrication theory in the quantifying the design life of heavily loaded components such as rolling element bearings and gears. Detailed guidelines for the design of oil and grease lubricated components are widely available and are being applied to the successful design of these components. However similar guidelines for water lubricated components are either not available or not well documented. It is often forgotten that the water was used as a lubricant in several components as far back as 1884 B.C. During the twentieth century the water lubricated components continued to play a major role in some high technology industries such as in the power generation plants. In CANDU nuclear reactors water lubrication of several critical components always occupied a pride place and in most cases the only practical mode of lubrication of several critical components always occupied a pride place and in most cases the only practical mode of lubrication. This paper presents some examples of the major water lubricated components in a CANDU reactors. Major part of the paper is focused on presenting an example of successful operating history of water lubricated bearings used in the HT pumps are presented. Both types of bearings have been qualified by tests for operation under normal as well as under more severe postulated condition of loss-of-coolant-accident (LOCA). These bearings have been designed to operate for the 30 years in the existing CANDU 6 (600 MW) reactors. However for the next generation of CANDU 6 reactors which go into service in the year 2003, the HT pump bearing life has been extended to 40 years. (author)

  17. Influence of Lubricant Pocket Geometry upon Lubrication Mechanisms on Tool-Workpiece Interfaces in Metal Forming

    DEFF Research Database (Denmark)

    Shimizu, I; Martins, P.A.F.; Bay, Niels

    2004-01-01

    mechanisms, during upsetting and strip drawing, by means of a rigid viscoplastic finite element formulation. Special emphasis is placed on the effect of pocket geometry on the build up of hydrostatic pressure, which is responsible for the onset of micro lubrication mechanisms. A good agreement is found...... between the numerically predicted and the experimentally measured distributions of hydrostatic stress....

  18. Numerical analysis of capillary compensated micropolar fluid lubricated hole-entry journal bearings

    Directory of Open Access Journals (Sweden)

    Nathi Ram

    2016-06-01

    Full Text Available The micropolar lubricated symmetric/asymmetric hole-entry bearings using capillary restrictor have been analyzed in the present work. Reynolds equation for micropolar lubricant has been derived and solved by FEM. The results have been computed using selected parameters of micropolar lubricant for hole-entry hydrostatic/hybrid journal bearings. A significant increase in damping and stiffness coefficients is observed for bearings having micropolar parameter N2=0.9, lm=10 than similar bearings under Newtonian lubricant. The threshold speed gets increased when symmetric bearing lubricated under micropolar fluid than Newtonian lubricant. The threshold speed gets increased when symmetric bearing lubricated under micropolar fluid than Newtonian lubricant.

  19. Modified Ionic Liquid-Based High-Performance Lubricants for Robotic Operations, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA needs an advanced lubrication solution for its future robotic systems and planetary surface assets. The required lubrication technology must offer...

  20. Enhanced lubricant film formation through micro-dimpled hard-on-hard artificial hip joint: An in-situ observation of dimple shape effects.

    Science.gov (United States)

    Choudhury, Dipankar; Rebenda, David; Sasaki, Shinya; Hekrle, Pavel; Vrbka, Martin; Zou, Min

    2018-05-01

    This study evaluates the impact of dimple shapes on lubricant film formation in artificial hip joints. Micro-dimples with 20-50 µm lateral size and 1 ± 0.2 µm depths were fabricated on CrCoMo hip joint femoral heads using a picosecond laser. Tribological studies were performed using a pendulum hip joint simulator to apply continuous swing flexion-extension motions. The results revealed a significantly enhanced lubricant film thickness (≥ 500 nm) with micro-dimpled prosthesis heads at equilibrium position after the lubricant film has fully developed. The average lubricant film thickness of dimpled prostheses with square- and triangular-shaped dimple arrays over time is about 3.5 that of the non-dimpled prosthesis (204 nm). Remarkably, the prosthesis with square-shaped dimple arrays showed a very fast lubricant film formation reaching their peak values within 0.5 s of pendulum movement, followed by prosthesis with triangular-shaped dimple arrays with a transition period of 42.4 s. The fully developed lubricant film thicknesses (≥ 700 nm) are significantly higher than the surface roughness (≈ 25 nm) demonstrating a hydrodynamic lubrication. Hardly any scratches appeared on the post-experimental prosthesis with square-shaped dimple array and only a few scratches were found on the post-experimental prosthesis with triangular-shaped dimple arrays. Thus, prostheses with square-shaped dimple arrays could be a potential solution for durable artificial hip joints. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Borax as a lubricant in powder metallurgy

    Directory of Open Access Journals (Sweden)

    Héctor Geovanny Ariza-Suarez

    2014-12-01

    were compacted at 700 MPa in a uniaxial press of 15 tons. DSC-TGA analysis of the mixture with borax was realized. The specimens were sintered in a plasma reactor at 1000 for 30 minutes, with a combined atmosphere of hydrogen and argon. Microhardness and density of the sintered samples was haracterized. XRD analysis was realized to detect possible compounds formation by interaction of borax. This paper shows that borax can be used as a lubricant in powder metallurgy.

  2. Nanotribology of Symmetric and Asymmetric Liquid Lubricants

    Directory of Open Access Journals (Sweden)

    Shinji Yamada

    2010-03-01

    Full Text Available When liquid molecules are confined in a narrow gap between smooth surfaces, their dynamic properties are completely different from those of the bulk. The molecular motions are highly restricted and the system exhibits solid-like responses when sheared slowly. This solidification behavior is very dependent on the molecular geometry (shape of liquids because the solidification is induced by the packing of molecules into ordered structures in confinement. This paper reviews the measurements of confined structures and friction of symmetric and asymmetric liquid lubricants using the surface forces apparatus. The results show subtle and complex friction mechanisms at the molecular scale.

  3. Process for the preparation of lubricants

    Energy Technology Data Exchange (ETDEWEB)

    Pier, M

    1927-06-04

    A process is described for preparation of lubricants from mixtures of hydrocarbons or hydrocarbon derivatives of mean molecular weight and nonaromatic nature, which is characterized by halogenating the raw oil by the action of halogens or halogen-exchanging compounds and submitting the obtained product to a condensation in presence of aluminum chloride, tin chloride, iron chloride, or other condensing metal chloride or boron fluoride or activated metals, such as activated aluminum, whereby it is worked up in two steps at a temperature below 150 and preferably below 100/sup 0/C.

  4. Piston-Skirt Lubrication System For Compressor

    Science.gov (United States)

    Schroeder, Edgar C.; Burzynski, Marion, Jr.

    1994-01-01

    Piston-skirt lubrication system provides steady supply of oil to piston rings of gas compressor. No need for oil-filled crankcase or external oil pump. Instead, part of each piston acts as its own oil pump circulating oil from reservoir. Annular space at bottom of piston and cylinder constitutes working volume of small oil pump. Depending on application, reservoir open to atmosphere, or sealed and pressurized in bellows to prevent contact between oil and atmosphere. Filter removes particles worn away from piston rings and cylinder wall during normal operation.

  5. Hydrodynamic bearing lubricated with magnetic fluids

    International Nuclear Information System (INIS)

    Urreta, H; Leicht, Z; Sanchez, A; Agirre, A; Kuzhir, P; Magnac, G

    2009-01-01

    This paper summarizes the work carried out in the development of hydrodynamic lubricated journal bearings with magnetic fluids. Two different fluids have been analyzed, one ferrofluid from FERROTEC APG s10n and one magnetorheological fluid from LORD Corp., MRF122-2ED. Theoretical analysis has been carried out with numerical solutions of Reynolds equation, based on apparent viscosity modulation for ferrofluid and Bingham model for MR fluid. To validate this model, one test bench has been designed, manufactured and set up, where preliminary results shown in this paper demonstrate that magnetic fluids can be used to develop active journal bearings.

  6. Lubrication in cold rolling : Numerical simulation using multigrid techniques

    NARCIS (Netherlands)

    Lugt, Pieter Martin

    1992-01-01

    In the cold rolling process a lubricant is applied on the rolls and/or the strip mate­rial. Due to the velocities of the rolls and the strip, part of the lubricant is sheared into the contact causing, amongst others, a reduction of the friction. In this thesis a physical-mathematical model is

  7. Self-lubricating polymer composites : Tribology and interface

    NARCIS (Netherlands)

    Shen, Jintao

    2015-01-01

    In cooperation with SKF, this PhD project focus on the improvement of the tribological performance of self-lubricating composites for dry sliding bearings. Several novel self-lubricating composites with very good performance and low production cost is developed in this research, which perform better

  8. Testing of environmentally friendly lubricants for sheet metal forming

    DEFF Research Database (Denmark)

    Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson

    2005-01-01

    the authors have especially been involved in the development of a system of test methods for sheet metal forming and in testing of friction and limits of lubrication of new, environmentally friendly lubricants. An overview of the developed tests is presented together with selected results....

  9. Prediction of limits of lubrication in strip reduction testing

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2004-01-01

    Pick-up and galling due to lubricant film breakdown is a severe limitation in cold forming of tribologically difficult metals like stainless steel and aluminium. The present paper describes a method of combined experimental and numerical analysis to quantify the limits of lubrication in a dedicated...

  10. Hydrophobins as aqueous lubricant additive for a soft sliding contact

    DEFF Research Database (Denmark)

    Lee, Seunghwan; Røn, Troels; Pakkanen, Kirsi I.

    2015-01-01

    lubrication characteristic is dominant via ‘self-healing’ mechanism. FpHYD5 revealed a better lubrication than HFBI presumably due to the presence of glycans and improved hydration of the sliding interface. Two type II hydrophobins function more favorably compared to a synthetic amphiphilic copolymer, PEO-PPO...

  11. Piston ring lubrication and hydrocarbon emissions from internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Froelund, K.

    1997-11-01

    Is it the intention with this project to improve the existing hydrocarbon emission model at the Institute by combining it with a model for predicting the piston ring lubrication. The piston ring lubrication model should be experimentally verified to ensure the validity of the model. The following items were the objectives of the current study: Develop a piston ring lubrication model. This implies the development of a ring-pack gas flow model; Examine the response of the piston ring lubrication model to changing engineer conditions. Especially, it would be interesting to look at the engine warm-up phase since this is the phase where the engine-out emissions are highest and where the commonly used three way catalyst is not capable of converting the engine-out emissions, thereby leading the engine-out emissions directly out in to the environment with the exhaust gases; In order to verify the piston ring lubrication model the lubricant distribution on the cylinder liner should be investigated experimentally. Here again it would be of great interesting to look at the engine warm-up phase; The piston ring lubrication model should be adjusted for application together with the new hydrocarbon emission model for SI-engines at the Institute in order to increase the accuracy of the latter; The piston ring lubrication model could be used for describing the transport of PAH`s in diesel engines. (EG)

  12. Mild wear modeling in the boundary lubrication regime

    NARCIS (Netherlands)

    Bosman, Rob

    2011-01-01

    Currently, the increasing demand for smaller and more efficient systems is increasing the stress put on interacting components. This forces components to operate in the boundary lubrication regime. In this lubrication regime, the normal load put on the components is no longer carried by the

  13. Temperature dependence on the synthesis of Jatropha bio lubricant

    International Nuclear Information System (INIS)

    Gunam Resul, M.F.M.; Tinia Idaty Mohd Ghazi; Idris, A.

    2009-01-01

    Full text: Jatropha oil has good potential as the renewable energy as well as lubricant feedstock. The synthesis of jatropha bio lubricant was performed by transesterification of jatropha methyl ester (JME) with trimethyl-ol-propane (TMP) with sodium methoxide (NaOCH 3 ) catalyst. The effects of temperature on the synthesis were studied at a range between 120 degree Celsius and 200 degree Celsius with pressure kept at 10 mbar. The conversion of JME to jatropha bio lubricant was found to be the highest (47 %) at 200 degree Celsius. However, it was suggested that the optimum temperature of the reaction is at 150 degree Celsius due to insignificant improvement in bio lubricant production. To maintain forward reaction, the excess amount of JME was maintained at 3.9:1 ratios to TMP. Kinetic study was done and compared. The synthesis was found to follow a second order reaction with overall rate constant of 1.49 x 10 -1 (% wt/ wt.min.degree Celsius) -1 . The estimated activation energy was 3.94 kJ/mol. Pour point for jatropha bio lubricant was at -3 degree Celsius and Viscosity Index (VI) ranged from 178 to 183. The basic properties of jatropha bio lubricant, pour point and viscosities are found comparable to other plant based bio lubricant, namely palm oil and soybean based bio lubricant. (author)

  14. Surface effects in adhesion, friction, wear, and lubrication

    National Research Council Canada - National Science Library

    Buckley, Donald H

    1981-01-01

    ... for carbon bodies to improve their wear resistance in high altitude aircraft generator applications. Basic researchers found that moisture in the carbon was critical t o its lubrication. Therefore, the presence of moisture o n the surface of the carbon was important. With it present, the carbon lubricated very effectively and very low wear was ...

  15. Adaptive system of supplying lubricant to the internal combustion engine

    Science.gov (United States)

    Barylnikova, E. P.; Kulakov, A. T.; Kulakov, O. A.

    2017-09-01

    This paper assesses the impact of reducing the pressure in the lubrication system on the failures of the crankshaft bearings. The method of adapting lubricating system of the diesel engine as the wear in operation and depending on the operation modes.

  16. Lubricant reflow after laser heating in heat assisted magnetic recording

    Science.gov (United States)

    Wu, Haoyu; Mendez, Alejandro Rodriguez; Xiong, Shaomin; Bogy, David B.

    2015-05-01

    In heat assisted magnetic recording (HAMR) technology for hard disk drives, the media will be heated to about 500 °C during the writing process in order to reduce its magnetic coercivity and thus allow data writing with the magnetic head transducers. The traditional lubricants such as Z-dol and Z-tetraol may not be able to perform in such harsh heating conditions due to evaporation, decomposition and thermal depletion. However, some of the lubricant depletion can be recovered due to reflow after a period of time, which can help to reduce the chance of head disk interface failure. In this study, experiments of lubricant thermal depletion and reflow were performed using a HAMR test stage for a Z-tetraol type lubricant. Various lubricant depletion profiles were generated using different laser heating conditions. The lubricant reflow process after thermal depletion was monitored by use of an optical surface analyzer. In addition, a continuum based lubrication model was developed to simulate the lubricant reflow process. Reasonably good agreement between simulations and experiments was achieved.

  17. Application of a Biodegradable Lubricant in a Diesel Vehicle

    DEFF Research Database (Denmark)

    Schramm, Jesper

    2003-01-01

    The IEA Advanced Motor Fuels Agreement has initiated this project concerning the application of biodegradable lubricants to diesel and gasoline type vehicles. Emission measurements on a chassis dynamometer were carried out. The purpose of these measurements was to compare the emissions of CO, CO2......, NOx, THC, PM, lubricant-SOF and PAH from one diesel and one gasoline type vehicle using biodegradable lubricants and conventional lubricants. This paper describes the results of the experiments with the diesel type vehicle only. Lubricant consumption and fuel consumption are other important parameters...... that have been evaluated during the experiments. Both vehicle types were operated on conventional crude oil based fuels and alternative fuels. The diesel vehicle was operated on conventional diesel fuel from a Danish fuel station, low sulfur diesel from Sweden and biodiesel, which was bought at a fuel...

  18. Tribological performance of nanoparticles as lubricating oil additives

    Energy Technology Data Exchange (ETDEWEB)

    Gulzar, M., E-mail: mubashir-nustian@hotmail.com; Masjuki, H. H., E-mail: masjuki@um.edu.my; Kalam, M. A.; Varman, M.; Zulkifli, N. W. M. [University of Malaya, Department of Mechanical Engineering, Faculty of Engineering, Centre for Energy Sciences (Malaysia); Mufti, R. A. [National University of Sciences and Technology (NUST) (Pakistan); Zahid, Rehan [University of Malaya, Department of Mechanical Engineering, Faculty of Engineering, Centre for Energy Sciences (Malaysia)

    2016-08-15

    The prospect of modern tribology has been expanded with the advent of nanomaterial-based lubrication systems, whose development was facilitated by the nanotechnology in recent years. In literature, a variety of nanoparticles have been used as lubricant additives with potentially interesting friction and wear properties. To date, although there has been a great deal of experimental research on nanoparticles as lubricating oil additives, many aspects of their tribological behavior are yet to be fully understood. With growing number of possibilities, the key question is: what types of nanoparticles act as a better lubricating oil additive and why? To answer this question, this paper reviews main types of nanoparticles that have been used as lubricants additives and outlines the mechanisms by which they are currently believed to function. Significant aspects of their tribological behavior such as dispersion stability and morphology are also highlighted.

  19. Compressibilities and viscosities of reference, vegetable, and synthetic gear lubricants

    DEFF Research Database (Denmark)

    Regueira Muñiz, Teresa; Lugo, Luis; Fernández, Josefa

    2014-01-01

    Nowadays, one of the primary choices of base oils for environmentally aware lubricants is vegetable oils. This is due to their good natural biodegradability and very low toxicity in combination with very good lubricity characteristics. The development of new vegetable-based lubricants requires...... values of six gear lubricants, two of them reference mineral oils and the other four developed biodegradable oils based in high oleic sunflower oil or in synthetic esters. It was found that all of the lubricants have both similar compressibilities and similar expansivities. Dowson and Higginson, Zhu.......06%. Dowson and Higginson and Zhu and Wen equations of state do not predict well the isothermal compressibilities, with AAD % being around 45% for both equations. Moreover, the viscosities were measured in the temperature range from 278.15 to 373.15 K at atmospheric pressure for these oils, and the viscosity...

  20. Tribological performance of nanoparticles as lubricating oil additives

    International Nuclear Information System (INIS)

    Gulzar, M.; Masjuki, H. H.; Kalam, M. A.; Varman, M.; Zulkifli, N. W. M.; Mufti, R. A.; Zahid, Rehan

    2016-01-01

    The prospect of modern tribology has been expanded with the advent of nanomaterial-based lubrication systems, whose development was facilitated by the nanotechnology in recent years. In literature, a variety of nanoparticles have been used as lubricant additives with potentially interesting friction and wear properties. To date, although there has been a great deal of experimental research on nanoparticles as lubricating oil additives, many aspects of their tribological behavior are yet to be fully understood. With growing number of possibilities, the key question is: what types of nanoparticles act as a better lubricating oil additive and why? To answer this question, this paper reviews main types of nanoparticles that have been used as lubricants additives and outlines the mechanisms by which they are currently believed to function. Significant aspects of their tribological behavior such as dispersion stability and morphology are also highlighted.

  1. Biodiesel as a lubricity additive for ultra low sulfur diesel

    Directory of Open Access Journals (Sweden)

    Subongkoj Topaiboul1 and 2,*

    2010-05-01

    Full Text Available With the worldwide trend to reduce emission from diesel engines, ultra low sulfur diesel has been introduced with thesulfur concentration of less than 10 ppm. Unfortunately, the desulfurization process inevitably reduces the lubricity of dieselfuel significantly. Alternatively, biodiesel, with almost zero sulfur content, has been added to enhance lubricity in an ultralow sulfur diesel. This work has evaluated the effectiveness of the biodiesel amount, sourced from palm and jatropha oil,and origin in ultra low sulfur diesel locally available in the market. Wear scar from a high-frequency reciprocating rig isbenchmarked to the standard value (460 m of diesel fuel lubricity. It was found that very small amount (less than 1% ofbiodiesel from either source significantly improves the lubricity in ultra low sulfur diesel, and the biodiesel from jatropha oilis a superior lubricity enhancer.

  2. Physical model for vaporization

    OpenAIRE

    Garai, Jozsef

    2006-01-01

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

  3. Petroleum Vapor - Field Technical

    Science.gov (United States)

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

  4. Immunity by equilibrium.

    Science.gov (United States)

    Eberl, Gérard

    2016-08-01

    The classical model of immunity posits that the immune system reacts to pathogens and injury and restores homeostasis. Indeed, a century of research has uncovered the means and mechanisms by which the immune system recognizes danger and regulates its own activity. However, this classical model does not fully explain complex phenomena, such as tolerance, allergy, the increased prevalence of inflammatory pathologies in industrialized nations and immunity to multiple infections. In this Essay, I propose a model of immunity that is based on equilibrium, in which the healthy immune system is always active and in a state of dynamic equilibrium between antagonistic types of response. This equilibrium is regulated both by the internal milieu and by the microbial environment. As a result, alteration of the internal milieu or microbial environment leads to immune disequilibrium, which determines tolerance, protective immunity and inflammatory pathology.

  5. Evaluation of Vapor Pressure and Ultra-High Vacuum Tribological Properties of Ionic Liquids (2) Mixtures and Additives

    Science.gov (United States)

    Morales, Wilfredo; Koch, Victor R.; Street, Kenneth W., Jr.; Richard, Ryan M.

    2008-01-01

    Ionic liquids are salts, many of which are typically viscous fluids at room temperature. The fluids are characterized by negligible vapor pressures under ambient conditions. These properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as space lubricants. In the previous paper we have measured the vapor pressure and some tribological properties of two distinct ionic liquids under simulated space conditions. In this paper we will present vapor pressure measurements for two new ionic liquids and friction coefficient data for boundary lubrication conditions in a spiral orbit tribometer using stainless steel tribocouples. In addition we present the first tribological data on mixed ionic liquids and an ionic liquid additive. Post mortem infrared and Raman analysis of the balls and races indicates the major degradation pathway for these two organic ionic liquids is similar to those of other carbon based lubricants, i.e. deterioration of the organic structure into amorphous graphitic carbon. The coefficients of friction and lifetimes of these lubricants are comparable to or exceed these properties for several commonly used space oils.

  6. Tribological properties and lubrication mechanism of in situ graphene-nickel matrix composite impregnated with lubricating oil

    Science.gov (United States)

    Lei, Yu; Du, Jinfang; Pang, Xianjuan; Wang, Haizhong; Yang, Hua; Jiang, Jinlong

    2018-05-01

    A solid-liquid synergetic lubricating system has been designed to develop a novel self-lubricating nickel matrix composite. The graphene-nickel (G-Ni) matrix composite with porous structure was fabricated by in situ growing graphene in bulk nickel using a powder metallurgy method. The porous structures of the composite were used to store polyalphaolefin (PAO) oil for self-lubricating. It is found that the G-Ni matrix composite under oil lubrication condition exhibited superior tribological properties as compared to pure nickel and the composite under dry sliding condition. The prestored oil was released from pores to the sliding surface forming a lubricating oil film during friction process. This lubricating oil film can protect the worn surface from severe oxidation, and help the formation and transfer of a carbon-based solid tribofilm derived from graphene and lubricating oil. This solid (graphene)-liquid (oil) synergistic lubricating mechanism is responsible for the reduction of friction coefficient and improvement of wear resistance of the in situ fabricated G-Ni matrix composite.

  7. Equilibrium shoreface profiles

    DEFF Research Database (Denmark)

    Aagaard, Troels; Hughes, Michael G

    2017-01-01

    Large-scale coastal behaviour models use the shoreface profile of equilibrium as a fundamental morphological unit that is translated in space to simulate coastal response to, for example, sea level oscillations and variability in sediment supply. Despite a longstanding focus on the shoreface...... profile and its relevance to predicting coastal response to changing environmental conditions, the processes and dynamics involved in shoreface equilibrium are still not fully understood. Here, we apply a process-based empirical sediment transport model, combined with morphodynamic principles to provide......; there is no tuning or calibration and computation times are short. It is therefore easily implemented with repeated iterations to manage uncertainty....

  8. Ball Bearings Equipped for In Situ Lubrication on Demand

    Science.gov (United States)

    Marchetti, Mario; Jones, William R., Jr.; Pepper, Stephen V.; Jansen, Mark; Predmore, Roamer

    2005-01-01

    In situ systems that provide fresh lubricants to ball/race contacts on demand have been developed to prolong the operational lives of ball bearings. These systems were originally intended to be incorporated into ball bearings in mechanisms that are required to operate in outer space for years, in conditions in which lubricants tend to deteriorate and/or evaporate. These systems may also be useful for similarly prolonging bearing lifetimes on Earth. Reservoirs have been among the means used previously to resupply lubricants. Lubricant- resupply reservoirs are bulky and add complexity to bearing assemblies. In addition, such a reservoir cannot be turned on or off as needed: it supplies lubricant continuously, often leading to an excess of lubricant in the bearing. A lubricator of the present type includes a porous ring cartridge attached to the inner or the outer ring of a ball bearing (see Figure 1). Oil is stored in the porous cartridge and is released by heating the cartridge: Because the thermal expansion of the oil exceeds that of the cartridge, heating causes the ejection of some oil. A metal film can be deposited on a face of the cartridge to serve as an electrical-resistance heater. The heater can be activated in response to a measured increase in torque that signals depletion of oil from the bearing/race contacts. Because the oil has low surface tension and readily wets the bearing-ring material, it spreads over the bearing ring and eventually reaches the ball/race contacts. The Marangoni effect (a surface-tension gradient associated with a temperature gradient) is utilized to enhance the desired transfer of lubricant to the ball/race contacts during heating. For a test, a ball bearing designed for use at low speed was assembled without lubricant and equipped with a porous-ring lubricator, the resistance heater of which consumed a power of less than 1 W when triggered on by a torque-measuring device. In the test, a load of 20 lb (.89 N) was applied and the

  9. Adhesion, friction, wear, and lubrication research by modern surface science techniques.

    Science.gov (United States)

    Keller, D. V., Jr.

    1972-01-01

    The field of surface science has undergone intense revitalization with the introduction of low-energy electron diffraction, Auger electron spectroscopy, ellipsometry, and other surface analytical techniques which have been sophisticated within the last decade. These developments have permitted submono- and monolayer structure analysis as well as chemical identification and quantitative analysis. The application of a number of these techniques to the solution of problems in the fields of friction, lubrication, and wear are examined in detail for the particular case of iron; and in general to illustrate how the accumulation of pure data will contribute toward the establishment of physiochemical concepts which are required to understand the mechanisms that are operational in friction systems. In the case of iron, LEED, Auger and microcontact studies have established that hydrogen and light-saturated organic vapors do not establish interfaces which prevent iron from welding, whereas oxygen and some oxygen and sulfur compounds do reduce welding as well as the coefficient of friction. Interpretation of these data suggests a mechanism of sulfur interaction in lubricating systems.

  10. Heat Transfer Enhancement During Water and Hydrocarbon Condensation on Lubricant Infused Surfaces.

    Science.gov (United States)

    Preston, Daniel J; Lu, Zhengmao; Song, Youngsup; Zhao, Yajing; Wilke, Kyle L; Antao, Dion S; Louis, Marcel; Wang, Evelyn N

    2018-01-11

    Vapor condensation is routinely used as an effective means of transferring heat or separating fluids. Dropwise condensation, where discrete droplets form on the condenser surface, offers a potential improvement in heat transfer of up to an order of magnitude compared to filmwise condensation, where a liquid film covers the surface. Low surface tension fluid condensates such as hydrocarbons pose a unique challenge since typical hydrophobic condenser coatings used to promote dropwise condensation of water often do not repel fluids with lower surface tensions. Recent work has shown that lubricant infused surfaces (LIS) can promote droplet formation of hydrocarbons. In this work, we confirm the effectiveness of LIS in promoting dropwise condensation by providing experimental measurements of heat transfer performance during hydrocarbon condensation on a LIS, which enhances heat transfer by ≈450% compared to an uncoated surface. We also explored improvement through removal of noncondensable gases and highlighted a failure mechanism whereby shedding droplets depleted the lubricant over time. Enhanced condensation heat transfer for low surface tension fluids on LIS presents the opportunity for significant energy savings in natural gas processing as well as improvements in thermal management, heating and cooling, and power generation.

  11. Microeconomics : Equilibrium and Efficiency

    NARCIS (Netherlands)

    Ten Raa, T.

    2013-01-01

    Microeconomics: Equilibrium and Efficiency teaches how to apply microeconomic theory in an innovative, intuitive and concise way. Using real-world, empirical examples, this book not only covers the building blocks of the subject, but helps gain a broad understanding of microeconomic theory and

  12. Differential Equation of Equilibrium

    African Journals Online (AJOL)

    user

    ABSTRACT. Analysis of underground circular cylindrical shell is carried out in this work. The forth order differential equation of equilibrium, comparable to that of beam on elastic foundation, was derived from static principles on the assumptions of P. L Pasternak. Laplace transformation was used to solve the governing ...

  13. Piezoelectric trace vapor calibrator

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  14. Comments on equilibrium, transient equilibrium, and secular equilibrium in serial radioactive decay

    International Nuclear Information System (INIS)

    Prince, J.R.

    1979-01-01

    Equations describing serial radioactive decay are reviewed along with published descriptions or transient and secular equilibrium. It is shown that terms describing equilibrium are not used in the same way by various authors. Specific definitions are proposed; they suggest that secular equilibrium is a subset of transient equilibrium

  15. Improvements to vapor generators

    International Nuclear Information System (INIS)

    Keller, Arthur; Monroe, Neil.

    1976-01-01

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

  16. Origins of extreme boundary lubrication by phosphatidylcholine liposomes.

    Science.gov (United States)

    Sorkin, Raya; Kampf, Nir; Dror, Yael; Shimoni, Eyal; Klein, Jacob

    2013-07-01

    Phosphatidylcholine (PC) vesicles have been shown to have remarkable boundary lubricating properties under physiologically-high pressures. Here we carry out a systematic study, using a surface force balance, of the normal and shear (frictional) forces between two opposing surfaces bearing different PC vesicles across water, to elucidate the origin of these properties. Small unilamellar vesicles (SUVs, diameters < 100 nm) of the symmetric saturated diacyl PCs DMPC (C(14)), DPPC (C(16)) and DSPC (C(18)) attached to mica surfaces were studied in their solid-ordered (SO) phase on the surface. Overall liposome lubrication ability improves markedly with increasing acyl chain length, and correlates strongly with the liposomes' structural integrity on the substrate surface: DSPC-SUVs were stable on the surface, and provided extremely efficient lubrication (friction coefficient μ ≈ 10(-4)) at room temperature at pressures up to at least 18 MPa. DMPC-SUVs ruptured following adsorption, providing poor high-pressure lubrication, while DPPC-SUVs behavior was intermediate between the two. These results can be well understood in terms of the hydration-lubrication paradigm, but suggest that an earlier conjecture, that highly-efficient lubrication by PC-SUVs depended simply on their being in the SO rather than in the liquid-disordered phase, should be more nuanced. Our results indicate that the resistance of the SUVs to mechanical deformation and rupture is the dominant factor in determining their overall boundary lubrication efficiency in our system. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Diesel fuel lubricity testing revisited : Tests von Dieselkraftstoffschmierfähigkeit erneut betrachtet

    NARCIS (Netherlands)

    van Leeuwen, H.J.

    2017-01-01

    Fuel is used as a lubricant in several engine components. Diesel fuel is known for its good lubrication properties, better than gasoline. These properties are examined in standard tests, as prescribed by ASTM. Good lubrication properties are designated as a good lubricity. Most commonly, fuel

  18. Enhanced Biodegradability, Lubricity and Corrosiveness of Lubricating Oil by Oleic Acid Diethanolamide Phosphate

    Directory of Open Access Journals (Sweden)

    Fang Jianhua

    2012-09-01

    Full Text Available Impacts of oleic acid diethanolamide phosphate (abbreviated as ODAP as an additive on biodegradability, anti-wear capacity, friction-reducing ability and corrosiveness of an unreadily biodegradable HVI 350 mineral lubricating oil was studied. The biodegradabilities of neat lubricating oil and its formulations with ODAP were evaluated on a biodegradation tester. Furthermore, the anti-wear and friction-reducing abilities and the corrosiveness of neat oil and the formulated oils were determined on a four-ball tribotester and a copper strip corrosion tester, respectively. The results indicated that ODAP markedly enhanced biodegradability as well as anti-wear and friction-reducing abilities of the lubricating oil. On the other hand, excellent color ratings of copper strips for both neat oil and the ODAP-doped oil were obtained in the corrosion tests, demonstrating that the corrosiveness of neat oil and the doped oil was negligible, although the latter seemed to provide slightly better anti-corrosion ability.

  19. Frictional lubricity enhanced by quantum mechanics.

    Science.gov (United States)

    Zanca, Tommaso; Pellegrini, Franco; Santoro, Giuseppe E; Tosatti, Erio

    2018-04-03

    The quantum motion of nuclei, generally ignored in the physics of sliding friction, can affect in an important manner the frictional dissipation of a light particle forced to slide in an optical lattice. The density matrix-calculated evolution of the quantum version of the basic Prandtl-Tomlinson model, describing the dragging by an external force of a point particle in a periodic potential, shows that purely classical friction predictions can be very wrong. The strongest quantum effect occurs not for weak but for strong periodic potentials, where barriers are high but energy levels in each well are discrete, and resonant Rabi or Landau-Zener tunneling to states in the nearest well can preempt classical stick-slip with nonnegligible efficiency, depending on the forcing speed. The resulting permeation of otherwise unsurmountable barriers is predicted to cause quantum lubricity, a phenomenon which we expect should be observable in the recently implemented sliding cold ion experiments.

  20. Tribofilms Forming in Oil-Lubricated Contacts

    Directory of Open Access Journals (Sweden)

    Matthias Scherge

    2016-07-01

    Full Text Available The subject of the present paper is the characterization of third bodies of run-in systems. By means of continuous friction and wear measurement, lubricated steel-steel and steel-aluminum contacts were evaluated. Microstructure, chemical composition and response of the materials to shear were analyzed by XPS/AES and focused ion beam technique. After a proper running-in, both systems developed a third body. The third body differs significantly from the base materials. In addition to adapted microstructure and near-surface chemistry, the third body exhibited a substructure characterized by a near-surface zone that accommodates shear and a second, deeper region that ensures strengthening.

  1. Lubricant distribution determination by neutron radiography

    International Nuclear Information System (INIS)

    Stewart, P.A.E.

    1979-01-01

    Cold neutron radiation of energy less than 0.025 eV having a flux greater than 1 x 10 3 neutrons/square centimeter/second is used to diagnose temporal information about the spatial distribution of hydrocarbon fuel and lubrication oils in internal combustion engines, gas turbine engines and fuel systems. Images of the movement of fuel or oil are recorded by directing a beam of neutrons through an engine and using an image intensifier responsive to low light levels to intensify an image formed by neutrons which have been directed through the engine onto a fluorescent screen. The output image from the intensifier is recorded by a video or cine camera

  2. Lubrication analysis of the thrust bearing in the main coolant pump of SMART

    International Nuclear Information System (INIS)

    Lee, J. S.; Park, J. S.; Kim, J. H.; Hur, H.; Kim, J. I.

    2001-01-01

    Thrust bearing and journal bearings are installed in the main coolant pump for SMART to support the rotating shaft with proper lubrication. The canned motor type main coolant pumps are arranged vertically on the reactor vessel and especially the MCP bearings are lubricated with water without external lubricating oil supply. Because axial load capacity of the thrust bearing can hardly meet requirement to acquire hydrodynamic or fluid film lubrication state, self-lubrication characteristics of silicon graphite meterials would be needed. Lubricational analysis method for thrust bearing for the main coolant pump of SMART is proposed, and lubricational characteristics of the bearing generated by solving the Reynolds equation are examined in this paper

  3. Nanomaterials in Lubricants: An Industrial Perspective on Current Research

    Directory of Open Access Journals (Sweden)

    Boris Zhmud

    2013-11-01

    Full Text Available This paper presents an overview on the use of various classes of nanomaterials in lubricant formulations. The following classes of nanomaterials are considered: fullerenes, nanodiamonds, ultradispersed boric acid and polytetrafluoroethylene (PTFE. Current advances in using nanomaterials in engine oils, industrial lubricants and greases are discussed. Results of numerous studies combined with formulation experience of the authors strongly suggest that nanomaterials do indeed have potential for enhancing certain lubricant properties, yet there is a long way to go before balanced formulations are developed.

  4. Numerical simulation of lubrication mechanisms at mesoscopic scale

    DEFF Research Database (Denmark)

    Hubert, C.; Bay, Niels; Christiansen, Peter

    2011-01-01

    The mechanisms of liquid lubrication in metal forming are studied at a mesoscopic scale, adopting a 2D sequential fluid-solid weak coupling approach earlier developed in the first author's laboratory. This approach involves two computation steps. The first one is a fully coupled fluid-structure F...... of pyramidal indentations. The tests are performed with variable reduction and drawing speed under controlled front and back tension forces. Visual observations through a transparent die of the fluid entrapment and escape from the cavities using a CCD camera show the mechanisms of Micro......PlastoHydroDynamic Lubrication (MPHDL) as well as cavity shrinkage due to lubricant compression and escape and strip deformation....

  5. Numerical methods and computers used in elastohydrodynamic lubrication

    Science.gov (United States)

    Hamrock, B. J.; Tripp, J. H.

    1982-01-01

    Some of the methods of obtaining approximate numerical solutions to boundary value problems that arise in elastohydrodynamic lubrication are reviewed. The highlights of four general approaches (direct, inverse, quasi-inverse, and Newton-Raphson) are sketched. Advantages and disadvantages of these approaches are presented along with a flow chart showing some of the details of each. The basic question of numerical stability of the elastohydrodynamic lubrication solutions, especially in the pressure spike region, is considered. Computers used to solve this important class of lubrication problems are briefly described, with emphasis on supercomputers.

  6. Studies on micro plasto hydrodymic lubrication in metal forming

    DEFF Research Database (Denmark)

    Bay, Niels; Bech, Jakob Ilsted; Andreasen, Jan Lasson

    2002-01-01

    The influence of work piece surface topography on friction and lubrication and final surface quality in metal forming operations is well known and has been pointed out by many researchers, see Schey (1983) and Bay and Wanheim (1990). This is especially the case when liquid lubrication is applied...... characterization models the potential entrapment of a lubricant in closed reservoirs is used as a parameter to predetermine the formability of a sheet metal, Steinhoff et al. (1996), Geiger et al. (1997) and Schmoeckel et al. (1997). In experimental studies on friction in metal forming applying the strip drawing...

  7. Regeneration of used lubricating oil as a source of energy

    Directory of Open Access Journals (Sweden)

    A. T. Abdulrahim

    2001-10-01

    Full Text Available Conservation of natural resources by refining used lubricating oil was attempted in this work. Used lubricating oil was purified and distilled. The distillates obtained were divided into two temperature ranges of 60 - 210°C and 210 - 310°C. Analyses of the physicochemical properties of the two samples revealed that they have similar properties with gasoline and diesel fuels respectively. This result shows that used lubricating oils, which are usually regarded as waste, can be regenerated to obtain useful hydrocarbons that can be used as fuels to power internal combustion engines

  8. Investigation of Lubrication Properties of Petroleum Fuel and Biohydrocarbon Blends

    Directory of Open Access Journals (Sweden)

    Gawron Bartosz

    2016-07-01

    Full Text Available The paper covers issues regarding lubricity of petroleum fuels used in piston and turbine engines, containing hydrocarbon biocomponents. Basing on available literature it can be said that the most prospective fuel components are biohydrocarbons. The paper describes effect of biohydrocarbons included in aviation fuel and diesel fuel on lubricity of such blends. The analysis covers two processes for obtaining biohydrocarbons, the HVO and the Fischer-Tropsch process. Due to problems with actual products acquiring, biohydrocarbons models representing chemically the actual ones from specific process. Lubricity testing was carried out according to standard test methods.

  9. Gasoline Reid Vapor Pressure

    Science.gov (United States)

    EPA regulates the vapor pressure of gasoline sold at retail stations during the summer ozone season to reduce evaporative emissions from gasoline that contribute to ground-level ozone and diminish the effects of ozone-related health problems.

  10. Prediction of refrigerant absorption and onset of natural convection in lubricant oil

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Jader R.; Marcelino Neto, Moises A. [Department of Mechanical Engineering, Federal University of Santa Catarina, Florianopolis, SC 88040900 (Brazil); Thoma, Stefan M. [Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology, Sonneggstrasse 3, 8092 Zurich (Switzerland)

    2008-11-15

    Refrigerant absorption and mixing in lubricant oil are important in the design of refrigeration compressors and refrigeration systems. Experimental work is reported on absorption of R-134a vapour through the top interface of an initially stagnant layer of pure lubricant oil. Since the liquid refrigerant is heavier than the oil, mixing is enhanced due to natural mass convection. In the present paper, the behaviour of the liquid temperature during absorption is described based on measurements carried out in a test rig consisting of a transparent 70 mm ID, 150 mm long, vertical glass tube through which absorption can be directly observed. Transient liquid temperatures were measured at three different heights in the test section (two in the vapour, one in the liquid). The experimental work is complemented by a theoretical analysis of the critical time for the onset of mass transfer induced Rayleigh instability. The model is based on a critical mass transfer Rayleigh number criterion widely reported in the literature and takes into account the variation of physical properties in the liquid layer. The critical time for the onset of natural mass convection increases with decreasing system pressure as a result of a lower equilibrium concentration at the vapour-liquid interface. (author)

  11. Equilibrium and pre-equilibrium emissions in proton-induced ...

    Indian Academy of Sciences (India)

    necessary for the domain of fission-reactor technology for the calculation of nuclear transmutation ... tions occur in three stages: INC, pre-equilibrium and equilibrium (or compound. 344. Pramana ... In the evaporation phase of the reaction, the.

  12. R-22 vapor explosions

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  13. Gated equilibrium bloodpool scintigraphy

    International Nuclear Information System (INIS)

    Reinders Folmer, S.C.C.

    1981-01-01

    This thesis deals with the clinical applications of gated equilibrium bloodpool scintigraphy, performed with either a gamma camera or a portable detector system, the nuclear stethoscope. The main goal has been to define the value and limitations of noninvasive measurements of left ventricular ejection fraction as a parameter of cardiac performance in various disease states, both for diagnostic purposes as well as during follow-up after medical or surgical intervention. Secondly, it was attempted to extend the use of the equilibrium bloodpool techniques beyond the calculation of ejection fraction alone by considering the feasibility to determine ventricular volumes and by including the possibility of quantifying valvular regurgitation. In both cases, it has been tried to broaden the perspective of the observations by comparing them with results of other, invasive and non-invasive, procedures, in particular cardiac catheterization, M-mode echocardiography and myocardial perfusion scintigraphy. (Auth.)

  14. Problems in equilibrium theory

    CERN Document Server

    Aliprantis, Charalambos D

    1996-01-01

    In studying General Equilibrium Theory the student must master first the theory and then apply it to solve problems. At the graduate level there is no book devoted exclusively to teaching problem solving. This book teaches for the first time the basic methods of proof and problem solving in General Equilibrium Theory. The problems cover the entire spectrum of difficulty; some are routine, some require a good grasp of the material involved, and some are exceptionally challenging. The book presents complete solutions to two hundred problems. In searching for the basic required techniques, the student will find a wealth of new material incorporated into the solutions. The student is challenged to produce solutions which are different from the ones presented in the book.

  15. Equilibrium statistical mechanics

    CERN Document Server

    Jackson, E Atlee

    2000-01-01

    Ideal as an elementary introduction to equilibrium statistical mechanics, this volume covers both classical and quantum methodology for open and closed systems. Introductory chapters familiarize readers with probability and microscopic models of systems, while additional chapters describe the general derivation of the fundamental statistical mechanics relationships. The final chapter contains 16 sections, each dealing with a different application, ordered according to complexity, from classical through degenerate quantum statistical mechanics. Key features include an elementary introduction t

  16. Volatility in Equilibrium

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Sizova, Natalia; Tauchen, George

    Stock market volatility clusters in time, carries a risk premium, is fractionally inte- grated, and exhibits asymmetric leverage effects relative to returns. This paper develops a first internally consistent equilibrium based explanation for these longstanding empirical facts. The model is cast i......, and the dynamic cross-correlations of the volatility measures with the returns calculated from actual high-frequency intra-day data on the S&P 500 aggregate market and VIX volatility indexes....

  17. Molecular equilibrium with condensation

    International Nuclear Information System (INIS)

    Sharp, C.M.; Huebner, W.F.

    1990-01-01

    Minimization of the Gibbs energy of formation for species of chemical elements and compounds in their gas and condensed phases determines their relative abundances in a mixture in chemical equilibrium. The procedure is more general and more powerful than previous abundance determinations in multiphase astrophysical mixtures. Some results for astrophysical equations of state are presented, and the effects of condensation on opacity are briefly indicated. 18 refs

  18. Equilibrium calculations, ch. 6

    International Nuclear Information System (INIS)

    Deursen, A.P.J. van

    1976-01-01

    A calculation is presented of dimer intensities obtained in supersonic expansions. There are two possible limiting considerations; the dimers observed are already present in the source, in thermodynamic equilibrium, and are accelerated in the expansion. Destruction during acceleration is neglected, as are processes leading to newly formed dimers. On the other hand one can apply a kinetic approach, where formation and destruction processes are followed throughout the expansion. The difficulty of this approach stems from the fact that the density, temperature and rate constants have to be known at all distances from the nozzle. The simple point of view has been adopted and the measured dimer intensities are compared with the equilibrium concentration in the source. The comparison is performed under the assumption that the detection efficiency for dimers is twice the detection efficiency for monomers. The experimental evidence against the simple point of view that the dimers of the onset region are formed in the source already, under equilibrium conditions, is discussed. (Auth.)

  19. Kinetics approach to modeling of polymer additive degradation in lubricants

    Institute of Scientific and Technical Information of China (English)

    llyaI.KUDISH; RubenG.AIRAPETYAN; Michael; J.; COVITCH

    2001-01-01

    A kinetics problem for a degrading polymer additive dissolved in a base stock is studied.The polymer degradation may be caused by the combination of such lubricant flow parameters aspressure, elongational strain rate, and temperature as well as lubricant viscosity and the polymercharacteristics (dissociation energy, bead radius, bond length, etc.). A fundamental approach tothe problem of modeling mechanically induced polymer degradation is proposed. The polymerdegradation is modeled on the basis of a kinetic equation for the density of the statistical distribu-tion of polymer molecules as a function of their molecular weight. The integrodifferential kineticequation for polymer degradation is solved numerically. The effects of pressure, elongational strainrate, temperature, and lubricant viscosity on the process of lubricant degradation are considered.The increase of pressure promotes fast degradation while the increase of temperature delaysdegradation. A comparison of a numerically calculated molecular weight distribution with an ex-perimental one obtained in bench tests showed that they are in excellent agreement with eachother.

  20. Nuclear fuel handling grapple carriage with self-lubricating bearing

    International Nuclear Information System (INIS)

    1977-01-01

    This invention relates to the provision of a fuel handling grapple carriage for a sodium cooled fast breeder reactor with sodium coolant lubricated bearings in which contamination of the bearings is prevented. (UK)

  1. Friction and Lubrication of Large Tilting-Pad Thrust Bearings

    Directory of Open Access Journals (Sweden)

    Michał Wasilczuk

    2015-04-01

    Full Text Available Fluid film bearings have been extensively used in the industry because of their unbeatable durability and extremely low friction coefficient, despite a very low coefficient of friction dissipation of energy being noticeable, especially in large bearings. Lubricating systems of large tilting pad thrust bearings utilized in large, vertical shaft hydrogenerators are presented in this paper. A large amount of heat is generated due to viscous shearing of the lubricant large tilting pad thrust bearings, and this requires systems for forced cooling of the lubricant. In the dominant bath lubrication systems, cooling is realized by internal coolers or external cooling systems, with the latter showing some important advantages at the cost of complexity and also, potentially, lower reliability. Substantial losses in the bearings, reaching 1 MW in extreme cases, are a good motivation for the research and development aimed at reducing them. Some possible methods and their potential efficiency, along with some effects already documented, are also described in the paper.

  2. Supporting Information Synthesis of fatty monoester lubricant base ...

    Indian Academy of Sciences (India)

    Synthesis of fatty monoester lubricant base oil catalyzed by Fe-Zn ... Physical properties of fatty acid monoesters viz., kinematic viscosity, viscosity index, density ... The analysis method involves titration of the diluted sample with ethanolic alkali ...

  3. Effects of Vaginal Lubricants on In-Vitro Progressive Spermatozoa ...

    African Journals Online (AJOL)

    USER

    African Journal of Reproductive Health September 2017; 21 (3): 96. ORIGINAL ... *For Correspondence: E-mail: Sureshk@dut.ac.za; Phone: +27-31-373-5291 .... marketed around the world. ... of many top selling brands of sexual lubricants to.

  4. Impact of lubrication on the tribological behaviour of PTFE ...

    Indian Academy of Sciences (India)

    bronze and bronze + molybdenum disulfide (MoS2) were considered. These composites were ... the PTFE composites have significantly been reduced in the lubricated condition ... there are no strong bonds between the fillers and the matrix in.

  5. Sexual lubricants in South Africa may potentially disrupt mucosal ...

    African Journals Online (AJOL)

    more likely to result in HIV transmission than unprotected vaginal intercourse due to ... Distribution of condoms and water-based sexual lubricants forms a cornerstone of .... Organisations such as the US Centers for Disease. Control and the ...

  6. On the energy economics of air lubrication drag reduction

    Directory of Open Access Journals (Sweden)

    Simo A. Mäkiharju

    2012-12-01

    Full Text Available Air lubrication techniques for frictional drag reduction on ships have been proposed by numerous researchers since the 19th century. However, these techniques have not been widely adopted as questions persist about their drag reduction performance beyond the laboratory, as well as energy and economic cost-benefit. This paper draws on data from the literature to consider the suitability of air lubrication for large ocean going and U.S. Great Lakes ships, by establishing the basic energy economic calculations and presenting results for a hypothetical air lubricated ship. All the assumptions made in the course of the analysis are clearly stated so that they can be refined when considering application of air lubrication to a specific ship. The analysis suggests that, if successfully implemented, both air layer and partial cavity drag reduction could lead to net energy savings of 10 to 20%, with corresponding reductions in emissions.

  7. Compatibility of refrigerants and lubricants with elastomers. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hamed, G.R.; Seiple, R.H.; Taikum, Orawan

    1994-01-01

    The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. In part I of the program the swell behavior in the test fluids has been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed fro the refrigerant test fluids and 24 hours after removal from the lubricants. Part II of the testing program includes the evaluation of tensile strength, hardness, weight, and dimensional changes after immersion aging in refrigerant/lubricant mixtures of selected elastomer formulations at elevated temperature and pressure.

  8. Noncompact Equilibrium Points and Applications

    Directory of Open Access Journals (Sweden)

    Zahra Al-Rumaih

    2012-01-01

    Full Text Available We prove an equilibrium existence result for vector functions defined on noncompact domain and we give some applications in optimization and Nash equilibrium in noncooperative game.

  9. Equilibrium thermodynamics - Callen's postulational approach

    NARCIS (Netherlands)

    Jongschaap, R.J.J.; Öttinger, Hans Christian

    2001-01-01

    In order to provide the background for nonequilibrium thermodynamics, we outline the fundamentals of equilibrium thermodynamics. Equilibrium thermodynamics must not only be obtained as a special case of any acceptable nonequilibrium generalization but, through its shining example, it also elucidates

  10. MHD equilibrium with toroidal rotation

    International Nuclear Information System (INIS)

    Li, J.

    1987-03-01

    The present work attempts to formulate the equilibrium of axisymmetric plasma with purely toroidal flow within ideal MHD theory. In general, the inertial term Rho(v.Del)v caused by plasma flow is so complicated that the equilibrium equation is completely different from the Grad-Shafranov equation. However, in the case of purely toroidal flow the equilibrium equation can be simplified so that it resembles the Grad-Shafranov equation. Generally one arbitrary two-variable functions and two arbitrary single variable functions, instead of only four single-variable functions, are allowed in the new equilibrium equations. Also, the boundary conditions of the rotating (with purely toroidal fluid flow, static - without any fluid flow) equilibrium are the same as those of the static equilibrium. So numerically one can calculate the rotating equilibrium as a static equilibrium. (author)

  11. Numerical Simulation of Piston Ring Lubrication

    DEFF Research Database (Denmark)

    Felter, Christian Lotz

    2006-01-01

    on solids and the equilibrium of stresses on the free surface. It is assumed that the surrounding gas phase has zero viscosity. Surface tension can be included in the model if necessary. The contact point where the three phases solid, liquid, and gas intersect is updated based on the velocity of the solid...

  12. Engineered Joint Lubrication for OA Prevention and Treatment

    Science.gov (United States)

    2015-09-01

    that work together with liquid lubricants to achieve low-friction systems. Lubrication between tissues is also important to maintain low-friction...movement within a number of biological systems, including the pleural cavity, the surface of the eye, visceral organs, and diarthroidal joints3. In...purified using reverse-phase high-performance liquid chromatography (C18 Grace-Vydac column) on a water/acetonitrile gradient. Purified peptides were

  13. Vapor pressures and enthalpies of vaporization of azides

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  14. Non-equilibrium thermodynamics

    CERN Document Server

    De Groot, Sybren Ruurds

    1984-01-01

    The study of thermodynamics is especially timely today, as its concepts are being applied to problems in biology, biochemistry, electrochemistry, and engineering. This book treats irreversible processes and phenomena - non-equilibrium thermodynamics.S. R. de Groot and P. Mazur, Professors of Theoretical Physics, present a comprehensive and insightful survey of the foundations of the field, providing the only complete discussion of the fluctuating linear theory of irreversible thermodynamics. The application covers a wide range of topics: the theory of diffusion and heat conduction, fluid dyn

  15. From red cells to soft porous lubrication.

    Science.gov (United States)

    Wu, Qianhong; Zhu, Zenghao; Nathan, Rungun

    2017-11-01

    In this paper, we report a novel experimental study to examine the lubrication theory for highly compressible porous media (Feng & Weinbaum, JFM, 422, 282, 2000), which was applied to the frictionless motion of red cells over the endothelial surface layer (ESL). The experimental setup consists of a running conveyer belt covered with a porous sheet, and an upper planar board, i.e. planing surface. The pore pressure generation was captured when the planing surface glides over the porous sheet. If the lateral leakage was eliminated, we found that the overall pore pressure's contribution to the total lift, fair 80%, and the friction coefficient η = 0.0981, when U =5 m/s, L =0.381 m, λ = h2/h0 = 1 and k =h2/h1 = 3, where U is the velocity of the conveyor belt; L is the planing surface length; h0, h1 and h2 are the undeformed, leading and trailing edge porous layer thickness, respectively. fair increases with the increase in U, λ and L, while decreases with the increase in k. η decreases with the increase in fair. If lateral pressure leakage exists, the pore pressure generation is reduced by nearly 90%. All the results agreed well with the theoretical predictions. The study here lays the foundation for applying soft porous media for new type of bearing with significantly reduced friction. This research was supported by the National Science Foundation (NSF CBET) under Award No. 1511096.

  16. Tendency of lubricating oil manufacturing process

    Energy Technology Data Exchange (ETDEWEB)

    Seki, Toshio

    1988-09-30

    The manufacturing method of paraffin base oil and the tendency are explained in details. The base oil is distillate of petroleum which is obtained at the high boiling of 400/degree/C or higher. The base oil is made from the distillate which is obtained through solvent deasphalting of the vacuum distillated residual oil. The refining process of those material is classified into the two different process steps such as refining and modifying process step in which the quality of the material is improved while eliminating unstable resin, aromatic compound, and sulfur contained in the material, and dewaxing process step in which the wax contained in the material is removed. The former is combination of the two different process steps such as solvent extraction process and hydrogen finishing process or hydroforming process. The latter is a combination of the two different process steps such as solvent dewaxing and catalytic dewaxing (hydro-dewaxing). Various examples of reactions, features and industrial processes are given in accordance with each of these process steps. Regarding the tendency toward the future, the kinds of materials will be expanded in the way that naphthene base oil will adopted as the material oil along with diversification of the quality of lubricating oil, and the processing technology including two-stage processing, catalytic dewaxing, etc. will be expected to be improved. 18 references, 11 figures, 7 tables.

  17. Thermal equilibrium of goats.

    Science.gov (United States)

    Maia, Alex S C; Nascimento, Sheila T; Nascimento, Carolina C N; Gebremedhin, Kifle G

    2016-05-01

    The effects of air temperature and relative humidity on thermal equilibrium of goats in a tropical region was evaluated. Nine non-pregnant Anglo Nubian nanny goats were used in the study. An indirect calorimeter was designed and developed to measure oxygen consumption, carbon dioxide production, methane production and water vapour pressure of the air exhaled from goats. Physiological parameters: rectal temperature, skin temperature, hair-coat temperature, expired air temperature and respiratory rate and volume as well as environmental parameters: air temperature, relative humidity and mean radiant temperature were measured. The results show that respiratory and volume rates and latent heat loss did not change significantly for air temperature between 22 and 26°C. In this temperature range, metabolic heat was lost mainly by convection and long-wave radiation. For temperature greater than 30°C, the goats maintained thermal equilibrium mainly by evaporative heat loss. At the higher air temperature, the respiratory and ventilation rates as well as body temperatures were significantly elevated. It can be concluded that for Anglo Nubian goats, the upper limit of air temperature for comfort is around 26°C when the goats are protected from direct solar radiation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Understanding Chemical Equilibrium Using Entropy Analysis: The Relationship between [delta]S[subscript tot](sys[superscript o]) and the Equilibrium Constant

    Science.gov (United States)

    Bindel, Thomas H.

    2010-01-01

    Entropy analyses as a function of the extent of reaction are presented for a number of physicochemical processes, including vaporization of a liquid, dimerization of nitrogen dioxide, and the autoionization of water. Graphs of the total entropy change versus the extent of reaction give a visual representation of chemical equilibrium and the second…

  19. Experimental study of vapor bubble dynamics

    International Nuclear Information System (INIS)

    Pasquini, Maria-Elena

    2015-01-01

    The object of this thesis is an experimental study of vapor bubble dynamics in sub-cooled nucleate boiling. The test section is locally heated by focusing a laser beam: heat fluxes from 1 e4 to 1.5 e6 W/m 2 and water temperature between 100 and 88 C have been considered. Three boiling regimes have been observed. Under saturated conditions and with low heat fluxes a developed nucleate boiling regime has been observed. Under higher sub-cooling and still with low heat fluxes an equilibrium regime has been observed in which the liquid flowrate evaporating at the bubble base is compensated by the vapor condensing flowrate at bubble top. A third regime have been observed at high heat fluxes for all water conditions: it is characterized by the formation of a large dry spot on the heated surface that keeps the nucleation site dry after bubble detachment. The condensation phase starts after bubble detachment. Bubble equivalent radius at detachment varies between 1 and 2.5 mm. Bubble properties have been measured and non-dimensional groups have been used to characterize bubble dynamics. Capillary waves have been observed on the bubble surface thanks to high-speed images acquisition. Two main phenomena have been proposed to explain capillary waves effects on bubble condensation: increasing of the phases interface area and decreasing of vapor bubble translation velocity, because of the increased drag force on the deformed bubble. (author) [fr

  20. Influence of Workpiece Surface Topography on the Mechanisms of Liquid Lubrication in Strip Drawing

    DEFF Research Database (Denmark)

    Shimizu, I; Andreasen, Jan Lasson; Bech, Jakob Ilsted

    2001-01-01

    The workpiece surface topography is an important factor controlling the mechanisms of lubrication in metal forming processes. In the present work, the microscopic lubrication mechanisms induced by lubricant trapped in pockets of the surface in strip drawing are studied. The experiments are perfor......The workpiece surface topography is an important factor controlling the mechanisms of lubrication in metal forming processes. In the present work, the microscopic lubrication mechanisms induced by lubricant trapped in pockets of the surface in strip drawing are studied. The experiments...

  1. Tribology and energy efficiency: from molecules to lubricated contacts to complete machines.

    Science.gov (United States)

    Taylor, Robert Ian

    2012-01-01

    The impact of lubricants on energy efficiency is considered. Molecular details of base oils used in lubricants can have a great impact on the lubricant's physical properties which will affect the energy efficiency performance of a lubricant. In addition, molecular details of lubricant additives can result in significant differences in measured friction coefficients for machine elements operating in the mixed/boundary lubrication regime. In single machine elements, these differences will result in lower friction losses, and for complete systems (such as cars, trucks, hydraulic circuits, industrial gearboxes etc.) lower fuel consumption or lower electricity consumption can result.

  2. Method to improve lubricity of low-sulfur diesel and gasoline fuels

    Science.gov (United States)

    Erdemir, Ali

    2004-08-31

    A method for providing lubricity in fuels and lubricants includes adding a boron compound to a fuel or lubricant to provide a boron-containing fuel or lubricant. The fuel or lubricant may contain a boron compound at a concentration between about 30 ppm and about 3,000 ppm and a sulfur concentration of less than about 500 ppm. A method of powering an engine to minimize wear, by burning a fuel containing boron compounds. The boron compounds include compound that provide boric acid and/or BO.sub.3 ions or monomers to the fuel or lubricant.

  3. Vapor liquid fraction determination

    International Nuclear Information System (INIS)

    1980-01-01

    This invention describes a method of measuring liquid and vapor fractions in a non-homogeneous fluid flowing through an elongate conduit, such as may be required with boiling water, non-boiling turbulent flows, fluidized bed experiments, water-gas mixing analysis, and nuclear plant cooling. (UK)

  4. Heat of vaporization spectrometer

    International Nuclear Information System (INIS)

    Edwards, D. Jr.

    1978-01-01

    Multilayer desorption measurements of various substances adsorbed on a stainless steel substrate are found to exhibit desorption profiles consistent with a zeroth order desorption model. The singleness of the desorption transients together with their narrow peak widths makes the technique ideally suited for a heat of vaporization spectrometer for either substance analysis or identification

  5. Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus

    Science.gov (United States)

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

    2007-01-01

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

  6. Observation of vapor pressure enhancement of rare-earth metal-halide salts in the temperature range relevant to metal-halide lamps

    Energy Technology Data Exchange (ETDEWEB)

    Curry, J. J.; Henins, A.; Hardis, J. E. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Estupinan, E. G. [Osram Sylvania Inc., Beverly, Massachusetts 01915 (United States); Lapatovich, W. P. [Independent Consultant, 51 Pye Brook Lane, Boxford, Massachusetts 01921 (United States); Shastri, S. D. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2012-02-20

    Total vapor-phase densities of Dy in equilibrium with a DyI{sub 3}/InI condensate and Tm in equilibrium with a TmI{sub 3}/TlI condensate have been measured for temperatures between 900 K and 1400 K. The measurements show strong enhancements in rare-earth vapor densities compared to vapors in equilibrium with the pure rare-earth metal-halides. The measurements were made with x-ray induced fluorescence on the sector 1-ID beam line at the Advanced Photon Source. The temperature range and salt mixtures are relevant to the operation of metal-halide high-intensity discharge lamps.

  7. Geotribology - Friction, wear, and lubrication of faults

    Science.gov (United States)

    Boneh, Yuval; Reches, Ze'ev

    2018-05-01

    We introduce here the concept of Geotribology as an approach to study friction, wear, and lubrication of geological systems. Methods of geotribology are applied here to characterize the friction and wear associated with slip along experimental faults composed of brittle rocks. The wear in these faults is dominated by brittle fracturing, plucking, scratching and fragmentation at asperities of all scales, including 'effective asperities' that develop and evolve during the slip. We derived a theoretical model for the rate of wear based on the observation that the dynamic strength of brittle materials is proportional to the product of load stress and loading period. In a slipping fault, the loading period of an asperity is inversely proportional to the slip velocity, and our derivations indicate that the wear-rate is proportional to the ratio of [shear-stress/slip-velocity]. By incorporating the rock hardness data into the model, we demonstrate that a single, universal function fits wear data of hundreds of experiments with granitic, carbonate and sandstone faults. In the next step, we demonstrate that the dynamic frictional strength of experimental faults is well explained in terms of the tribological parameter PV factor (= normal-stress · slip-velocity). This factor successfully delineates weakening and strengthening regimes of carbonate and granitic faults. Finally, our analysis revealed a puzzling observation that wear-rate and frictional strength have strikingly different dependencies on the loading conditions of normal-stress and slip-velocity; we discuss sources for this difference. We found that utilization of tribological tools in fault slip analyses leads to effective and insightful results.

  8. Lubrication of Space Shuttle Main Engine Turbopump Bearings

    Science.gov (United States)

    Gibson, Howard; Munafo, Paul (Technical Monitor)

    2001-01-01

    The Space Shuttle has three main engines that are used for propulsion into orbit. These engines are fed propellants by four turbopumps on each engine. A main element in the turbopump is the bearings supporting the rotor that spins the turbine blades and the pump impeller. These bearings are required to spin at very high speeds, support radial and thrust loads, and have high wear resistance without the benefit of lubrication. The liquid hydrogen and oxygen propellants flow through the bearings to cool the surfaces. The volatile nature of the propellants excludes any conventional means of lubrication. Lubrication for these bearings is provided by the ball separator inside the bearing. The separator is a composite material that supplies a transfer film of lubrication to the rings and balls. New separator materials and lubrication schemes have been investigated at Marshall Space Flight Center in a bearing test rig with promising results. Hybrid bearings with silicon nitride balls have also been evaluated. The use of hybrid, silicon nitride ball bearings in conjunction -with better separator materials has shown excellent results. The work that Marshall has done is being utilized in turbopumps flying on the space shuttle fleet and will be utilized in future space travel. This result of this work is valuable for all aerospace and commercial applications where high-speed bearings are used.

  9. Growth and opportunities in the lubricants business in Asia

    International Nuclear Information System (INIS)

    Burke, B.F.

    1995-01-01

    The demand for lubricants is increasing faster in Asia than any other part of the world. This development is being propelled largely by the expansion of the transportation and manufacturing sectors. By the year 2000, lubricant consumption in Asia will exceed that of Western Europe, Africa and the Middle East combined. Aside from this growth, most of the region is shifting from very low quality to higher quality value-added products. In view of these factors, there has been an explosion of activity over the past few years as lubricant blenders and additive suppliers attempt to position themselves within the market. Over the past year, Chem Systems has undertaken an extensive study of the lubricants business in East Asia, focusing on the evolution of this complex market structure and the identification of attractive opportunities. The overview presented in this paper is a product of these efforts. Whether you are a multinational oil company, independent blender, national oil company or multinational additive suppler, the questions are the same when developing a strategy for the region: regional overview of lubricant business structure; outlook for Asian demand; profile of lube/additives businesses; and successful competition--what is required?

  10. Gear Mesh Loss-of-Lubrication Experiments and Analytical Simulation

    Science.gov (United States)

    Handschuh, Robert F.; Polly, Joseph; Morales, Wilfredo

    2011-01-01

    An experimental program to determine the loss-of-lubrication (LOL) characteristics of spur gears in an aerospace simulation test facility has been completed. Tests were conducted using two different emergency lubricant types: (1) an oil mist system (two different misted lubricants) and (2) a grease injection system (two different grease types). Tests were conducted using a NASA Glenn test facility normally used for conducting contact fatigue. Tests were run at rotational speeds up to 10000 rpm using two different gear designs and two different gear materials. For the tests conducted using an air-oil misting system, a minimum lubricant injection rate was determined to permit the gear mesh to operate without failure for at least 1 hr. The tests allowed an elevated steady state temperature to be established. A basic 2-D heat transfer simulation has been developed to investigate temperatures of a simulated gear as a function of frictional behavior. The friction (heat generation source) between the meshing surfaces is related to the position in the meshing cycle, the load applied, and the amount of lubricant in the contact. Experimental conditions will be compared to those from the 2-D simulation.

  11. Equilibrium models and variational inequalities

    CERN Document Server

    Konnov, Igor

    2007-01-01

    The concept of equilibrium plays a central role in various applied sciences, such as physics (especially, mechanics), economics, engineering, transportation, sociology, chemistry, biology and other fields. If one can formulate the equilibrium problem in the form of a mathematical model, solutions of the corresponding problem can be used for forecasting the future behavior of very complex systems and, also, for correcting the the current state of the system under control. This book presents a unifying look on different equilibrium concepts in economics, including several models from related sciences.- Presents a unifying look on different equilibrium concepts and also the present state of investigations in this field- Describes static and dynamic input-output models, Walras, Cassel-Wald, spatial price, auction market, oligopolistic equilibrium models, transportation and migration equilibrium models- Covers the basics of theory and solution methods both for the complementarity and variational inequality probl...

  12. Grinding kinetics and equilibrium states

    Science.gov (United States)

    Opoczky, L.; Farnady, F.

    1984-01-01

    The temporary and permanent equilibrium occurring during the initial stage of cement grinding does not indicate the end of comminution, but rather an increased energy consumption during grinding. The constant dynamic equilibrium occurs after a long grinding period indicating the end of comminution for a given particle size. Grinding equilibrium curves can be constructed to show the stages of comminution and agglomeration for certain particle sizes.

  13. Mental Equilibrium and Rational Emotions

    OpenAIRE

    Eyal Winter; Ignacio Garcia-Jurado; Jose Mendez-Naya; Luciano Mendez-Naya

    2009-01-01

    We introduce emotions into an equilibrium notion. In a mental equilibrium each player "selects" an emotional state which determines the player's preferences over the outcomes of the game. These preferences typically differ from the players' material preferences. The emotional states interact to play a Nash equilibrium and in addition each player's emotional state must be a best response (with respect to material preferences) to the emotional states of the others. We discuss the concept behind...

  14. Effect of the External Lubrication Method for a Rotary Tablet Press on the Adhesion of the Film Coating Layer.

    Science.gov (United States)

    Kondo, Hisami; Toyota, Hiroyasu; Kamiya, Takayuki; Yamashita, Kazunari; Hakomori, Tadashi; Imoto, Junko; Kimura, Shin-Ichiro; Iwao, Yasunori; Itai, Shigeru

    2017-01-01

    External lubrication is a useful method which reduces the adhesion of powder to punches and dies by spraying lubricants during the tableting process. However, no information is available on whether the tablets prepared using an external lubrication system can be applicable for a film coating process. In this study, we evaluated the adhesion force of the film coating layer to the surface of tablets prepared using an external lubrication method, compared with those prepared using internal lubrication method. We also evaluated wettability, roughness and lubricant distribution state on the tablet surface before film coating, and investigated the relationship between peeling of the film coating layer and these tablet surface properties. Increasing lubrication through the external lubrication method decreased wettability of the tablet surface. However, no change was observed in the adhesion force of the film coating layer. On the other hand, increasing lubrication through the internal lubrication method, decreased both wettability of the tablet surface and the adhesion force of the film coating layer. The magnesium stearate distribution state on the tablet surface was assessed using an X-ray fluorescent analyzer and lubricant agglomerates were observed in the case of the internal lubrication method. However, the lubricant was uniformly dispersed in the external lubrication samples. These results indicate that the distribution state of the lubricant affects the adhesion force of the film coating layer, and external lubrication maintained sufficient lubricity and adhesion force of the film coating layer with a small amount of lubricant.

  15. Vapor pressure and enthalpy of vaporization of linear aliphatic alkanediamines

    International Nuclear Information System (INIS)

    Pozdeev, Vasiliy A.; Verevkin, Sergey P.

    2011-01-01

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

  16. Assessment of lubricating oil degradation in small motorcycle engine fueled with gasohol

    Directory of Open Access Journals (Sweden)

    Nakorn Tippayawong

    2010-05-01

    Full Text Available Assessment of the degradation of lubricating oil was performed on the lubricants which had been used in a small motorcycle engine fueled with gasohol in comparison with the lubricants from gasoline-run engine. The lubricant properties examined in the assessment were lubricating capacity, viscosity and stability to oxidation. Lubricating capacity was evaluated by accelerated wear test on the Timken tester. Lubricating oils from gasohol-run engine appeared to produce about 10% greater wear than that made in oils from gasoline-run engine. There was no significant difference between the effect of gasohol and gasoline on the viscosity of the used lubricating oils. Moreover, no oxidation products in any used oil samples could be detected.

  17. WATER-EMULSION LUBRICANTS FOR PRESS-MODES OF CASTING UNDER PRESSURE

    Directory of Open Access Journals (Sweden)

    A. M. Mihaltsov

    2005-01-01

    Full Text Available It is shown that for more successful using of wateremulsion lubricants it is necessary to use new lubricating component. One of such component is complex component on the basis of siloxanes.

  18. Fe-Modeling Of Starved Hydrodynamic Lubrication With Free Surface Effects

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Vølund, Anders; Klit, Peder

    2017-01-01

    This work concerns a new finite-element formulation for solving hydrody-namic lubrication problems that include partially flooded regions, where the lubricant film behavior is governed by free surface flow....

  19. Boundary Lubrication of PEO-PPO-PEO Triblock Copolymer Physisorbed on Polypropylene, Polyethylene, and Cellulose Surfaces

    KAUST Repository

    Li, Yangyang; Rojas, O. J.; Hinestroza, J. P.

    2012-01-01

    to the affinity of the polymer with the substrate. Further experiments were performed to mimic practical operations involving lubricant addition during manufacturing and postprocessing removal. XPS was used to verify the presence of the lubricant on the polymeric

  20. Friction and lubrication modelling in sheet metal forming: Influence of lubrication amount, tool roughness and sheet coating on product quality

    Science.gov (United States)

    Hol, J.; Wiebenga, J. H.; Carleer, B.

    2017-09-01

    In the stamping of automotive parts, friction and lubrication play a key role in achieving high quality products. In the development process of new automotive parts, it is therefore crucial to accurately account for these effects in sheet metal forming simulations. This paper presents a selection of results considering friction and lubrication modelling in sheet metal forming simulations of a front fender product. For varying lubrication conditions, the front fender can either show wrinkling or fractures. The front fender is modelled using different lubrication amounts, tool roughness’s and sheet coatings to show the strong influence of friction on both part quality and the overall production stability. For this purpose, the TriboForm software is used in combination with the AutoForm software. The results demonstrate that the TriboForm software enables the simulation of friction behaviour for varying lubrication conditions, i.e. resulting in a generally applicable approach for friction characterization under industrial sheet metal forming process conditions.

  1. The State of the Art in Cold Forging Lubrication

    DEFF Research Database (Denmark)

    Bay, Niels

    1994-01-01

    The manufature of components in steel, aluminium and copper alloys by cold forging production has increased ever since the 1950's. Typical processes are forward rod extrusion and backward can extrusion, upsetting, ironing, tube extrusion and radial extrusion. The tribological conditions in cold...... forging are extremely severe due to large surface expansion and normal pressure in the tool/workpiece interface combined with elevated tool temperatures. Except for the more simple cold forging operations successful production therefore requires advanced lubrication systems. The present paper gives...... a detailed description of the state of art for lubricant systems for cold forging of C-steels and low alloy steels as well as aluminium alloys including all the basic operations such as cleaning of the slugs, application of eventual conversion coating and lubrication. As regards cold forging of steel...

  2. Coefficient of friction of a starved lubricated spur gear pair

    International Nuclear Information System (INIS)

    Liu, Huaiju; Zhu, Caichao; Sun, Zhangdong; Zhang, Yuanyuan; Song, Chaosheng

    2016-01-01

    The frictional power loss issue of gear pairs becomes an important concern in both industry and academia due to the requirement of the energy saving and the improvement of power density of gear drives. A thermal starved elastohydrodynamic lubrication model is developed to study the tribological performance of a spur gear pair under starved lubrication conditions. The contact pressure, the film thickness, the temperature rise, the frictional power loss, as well as the coefficient of friction are evaluated by considering the variation of the curvature radius, the sliding/rolling motion, and the load distribution of gear tooth within the meshing period. Effects of lubrication starvation condition, load and speed on the coefficient of friction are studied.

  3. Feasibility study of self-lubrication by chlorine implantation

    International Nuclear Information System (INIS)

    Akhajdenung, T.; Aizawa, T.; Yoshitake, M.; Mitsuo, A.

    2003-01-01

    Implantation of chlorine into titanium nitride (TiN) coating on the high-speed steel substrate has succeeded in significant reduction of wear rate and friction coefficient for original TiN under dry wear condition. Through precise investigation on the surface reaction in the wear track, in situ formation of oxygen-deficient titanium oxides was found to play a role as a lubricious oxide. In the present paper, this self-lubrication mechanism is further investigated for various wearing conditions. For wide range of sliding speed and normal load in the wear map, the wear volume of a counter material is actually reduced with comparison to the un-implanted TiN. Effect of the ion implantation dose on this self-lubrication mechanism is also studied for practical use. Some comments are made on further application of this self-lubrication to manufacturing

  4. Controllable sliding bearings and controllable lubrication principles-an overview

    DEFF Research Database (Denmark)

    Santos, Ilmar F.

    2018-01-01

    -mechanical actuators have been coupled to such bearings. Depending on (i) the actuator type; (ii) the actuation principle, i.e., hydraulic, pneumatic, piezoelectric or magnetic among others; and (iii) how such an actuator is coupled to the sliding bearings, different regulation and control actions of fluid film...... bearing gap and its preload via moveable and compliant sliding surfaces; and (d) the control of the lubricant viscosity. All four parameters, i.e., pressure, flow (velocity profiles), gap and viscosity, are explicit parameters in the modified form of Reynolds' equations for active lubrication....... In this framework, this paper gives one main original contribution to the state-of-the-art of radial sliding bearings and controllable lubrication: a comprehensive overview about the different types of controllable sliding bearings and principles used by several authors. The paper ends with some conclusive remarks...

  5. Oils; lubricants; paraffin-wax compositions; hydrocarbon condensation products

    Energy Technology Data Exchange (ETDEWEB)

    1934-04-04

    Petroleum hydrocarbons such as gasoline, kerosene, Diesel fuel oil, lubricating-oil, and paraffin wax, and like hydrocarbons such as are obtainable from shale oil and by the hydrogenation of carbonaceous materials, are improved by addition of products obtained by condensing a cyclic hydrocarbon with a saturated dihalogen derivative of an aliphatic hydrocarbon containing less than five carbon atoms. The addition of the condensation products increases the viscosity of the hydrocarbon oils specified, and is particularly useful in the case of lubricating-oils; addition of the condensation products to paraffin wax increases the transparency and adherent properties of the wax, and is useful in the manufacture of moulded articles such as candles; the products may also be used in solid lubricating-compositions.

  6. Elastic model of the traction behavior of two traction lubricants

    Science.gov (United States)

    Loewenthal, S. H.; Rohn, D. A.

    1984-01-01

    In the analysis of rolling-sliding concentrated contacts, such as gears, bearings and traction drives, the traction characteristics of the lubricant are of prime importance. The elastic shear modulus and limiting shear stress properties of the lubricant dictate the traction/slip characteristics and power loss associated with an EHD contact undergoing slip and/or spin. These properties can be deducted directly from the initial slope m and maximum traction coefficient micron of an experimental traction curve. In this investigation, correlation equations are presented to predict m and micron for two modern traction fluids based on the regression analysis of 334 separate traction disk machine experiments. The effects of contact pressure, temperature, surface velocity, ellipticity ratio are examined. Problems in deducing lubricant shear moduli from disk machine tests are discussed. Previously announced in STAR as N83-20116

  7. An Advanced Microturbine System with Water-Lubricated Bearings

    Directory of Open Access Journals (Sweden)

    Susumu Nakano

    2009-01-01

    Full Text Available A prototype of the next-generation, high-performance microturbine system was developed for laboratory evaluation. Its unique feature is its utilization of water. Water is the lubricant for the bearings in this first reported application of water-lubricated bearings in gas turbines. Bearing losses and limitations under usage conditions were found from component tests done on the bearings and load tests done on the prototype microturbine. The rotor system using the water-lubricated bearings achieved stable rotating conditions at a rated rotational speed of 51,000 rpm. An electrical output of 135 kW with an efficiency of more than 33% was obtained. Water was also utilized to improve electrical output and efficiency through water atomizing inlet air cooling (WAC and a humid air turbine (HAT. The operation test results for the WAC and HAT revealed the WAC and HAT operations had significant effects on both electrical output and electrical efficiency.

  8. IUTAM Symposium on Lubricated Transport of Viscous Materials

    CERN Document Server

    1998-01-01

    The main objective of the First International Symposium on Lubricated Transport of Viscous Materials was to bring together scientists and engineers from academia and industryto discuss current research work and exchange ideas in this newly emerging field. It is an area offluid dynamics devoted to laying bare the principlesofthe lubricated transport of viscous materials such as crude oil, concentrated oil/water emulsion, slurries and capsules. It encompasses several types of problem. Studies of migration of particulates away from walls, Segre-Silverberg effects, lubrication versus lift and shear-induced migration belong to one category. Some of the technological problems are the fluid dynamics ofcore flows emphasizing studies ofstability, problems of start-up, lift-off and eccentric flow where gravity causes the core flow to stratify. Another category of problems deals with the fouling of pipe walls with oil, with undesirable increases in pressure gradients and even blocking. This study involves subjects like ...

  9. Predictive modelling of fatigue failure in concentrated lubricated contacts.

    Science.gov (United States)

    Evans, H P; Snidle, R W; Sharif, K J; Bryant, M J

    2012-01-01

    Reducing frictional losses in response to the energy agenda will require use of less viscous lubricants causing hydrodynamically-lubricated bearings to operate with thinner films leading to "mixed lubrication" conditions in which a degree of direct interaction occurs between surfaces protected only by boundary tribofilms. The paper considers the consequences of thinner films and mixed lubrication for concentrated contacts such as those occurring between the teeth of power transmission gears and in rolling element bearings. Surface fatigue in gears remains a serious problem in demanding applications, and its solution will become more pressing with the tendency towards thinner oils. The particular form of failure examined here is micropitting, which is identified as a fatigue phenomenon occurring at the scale of the surface roughness asperities. It has emerged recently as a systemic difficulty in the operation of large scale wind turbines where it occurs in both power transmission gears and their support bearings. Predictive physical modelling of these contacts requires a transient mixed lubrication analysis for conditions in which the predicted lubricant film thickness is of the same order or significantly less than the height of surface roughness features. Numerical solvers have therefore been developed which are able to deal with situations in which transient solid contacts occur between surface asperity features under realistic engineering conditions. Results of the analysis, which reveal the detailed time-varying behaviour of pressure and film clearance, have been used to predict fatigue and damage accumulation at the scale of surface asperity features with the aim of improving understanding of the micropitting phenomenon. The possible consequences on fatigue of residual stress fields resulting from plastic deformation of surface asperities is also considered.

  10. The effect of inertia force in water lubricated thrust bearings of canned reactor coolant pump

    International Nuclear Information System (INIS)

    Deng Liping

    1994-01-01

    The water lubricated thrust bearings are analyzed. According to characteristic of low viscosity of water the lubricated equation for design and calculation of water lubricated thrust bearings is established. The calculation and analyses show that the effect of inertia force in water lubricated thrust bearings should not be neglected except the conditions of low speed, high angle of inclination and low radius ratio of pad

  11. INVESTIGATION OF FLOW BEHAVIOR IN MINIMUM QUANTITY LUBRICATION NOZZLE FOR END MILLING PROCESSES

    OpenAIRE

    M.S. Najiha; M.M.Rahman; A.R. Yusoff; K. Kadirgama

    2012-01-01

    Minimum quantity lubrication (MQL) is a sustainable manufacturing technique that has replaced conventional flooded lubrication methods and dry machining. In the MQL technique, the lubricant is sprayed onto the friction surfaces through nozzles through small pneumatically-operated pumps. This paper presents an investigation into the flow behavior of the lubricant and air mixture under certain pressures at the tip of a nozzle specially designed for MQL. The nozzle used is an MQL stainless steel...

  12. Constrained Vapor Bubble Experiment

    Science.gov (United States)

    Gokhale, Shripad; Plawsky, Joel; Wayner, Peter C., Jr.; Zheng, Ling; Wang, Ying-Xi

    2002-11-01

    Microgravity experiments on the Constrained Vapor Bubble Heat Exchanger, CVB, are being developed for the International Space Station. In particular, we present results of a precursory experimental and theoretical study of the vertical Constrained Vapor Bubble in the Earth's environment. A novel non-isothermal experimental setup was designed and built to study the transport processes in an ethanol/quartz vertical CVB system. Temperature profiles were measured using an in situ PC (personal computer)-based LabView data acquisition system via thermocouples. Film thickness profiles were measured using interferometry. A theoretical model was developed to predict the curvature profile of the stable film in the evaporator. The concept of the total amount of evaporation, which can be obtained directly by integrating the experimental temperature profile, was introduced. Experimentally measured curvature profiles are in good agreement with modeling results. For microgravity conditions, an analytical expression, which reveals an inherent relation between temperature and curvature profiles, was derived.

  13. Industrial tribology tribosystems, friction, wear and surface engineering, lubrication

    CERN Document Server

    Mang, Theo; Bartels, Thorsten

    2010-01-01

    Integrating very interesting results from the most important R & D project ever made in Germany, this book offers a basic understanding of tribological systems and the latest developments in reduction of wear and energy consumption by tribological measures. This ready reference and handbook provides an analysis of the most important tribosystems using modern test equipment in laboratories and test fields, the latest results in material selection and wear protection by special coatings and surface engineering, as well as with lubrication and lubricants.This result is a quick introductio

  14. Testing of Lubricant Performance in Sheet Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels; Olsson, David Dam; Friis, Kasper Leth

    2008-01-01

    Increasing focus on environmental issues in industrial production has urged a number of sheet metal forming companies to look for new tribo-systems in order to substitute hazardous lubricants such as chlorinated paraffin oils. The problems are especially pronounced, when forming tribologically...... of the lubricant film causing pick-up of work piece material on the tool surface and scoring of subsequent work piece surfaces. The present paper gives an overview of more than 10 years work by the authors’ research group through participation in national as well as international framework programmes on developing...

  15. Mixed Mechanism of Lubrication by Lipid Bilayer Stacks.

    Science.gov (United States)

    Boţan, Alexandru; Joly, Laurent; Fillot, Nicolas; Loison, Claire

    2015-11-10

    Although the key role of lipid bilayer stacks in biological lubrication is generally accepted, the mechanisms underlying their extreme efficiency remain elusive. In this article, we report molecular dynamics simulations of lipid bilayer stacks undergoing load and shear. When the hydration level is reduced, the velocity accommodation mechanism changes from viscous shear in hydration water to interlayer sliding in the bilayers. This enables stacks of hydrated lipid bilayers to act as efficient boundary lubricants for various hydration conditions, structures, and mechanical loads. We also propose an estimation for the friction coefficient; thanks to the strong hydration forces between lipid bilayers, the high local viscosity is not in contradiction with low friction coefficients.

  16. Tribology - friction, lubrication and wear: fifty years on. 2 v

    International Nuclear Information System (INIS)

    1987-01-01

    The paper presents the proceedings of the International Tribology Conference held in London (United Kingdom), 1987, and organised by the Institution of Mechanical Engineers. The aim of the conference was to address the current status and future developments in all aspects of tribology. The conference proceedings contained 121 papers, and the sessions were structured under six headings: hydrodynamic, elastohydrodynamic and mixed lubrication; friction and wear; contact mechanics; materials; design and applications; and lubricants. Four papers were chosen for INIS and indexed separately. (U.K.)

  17. Analysis of a thioether lubricant by infrared Fourier microemission spectrophotometry

    Science.gov (United States)

    Jones, W. R., Jr.; Morales, W.; Lauer, J. L.

    1986-01-01

    An infrared Fourier microemission spectrophotometer is used to obtain spectra (wavenumber range, 630 to 1230 0.1 cm) from microgram quantities of thioether lubricant samples deposited on aluminum foil. Infrared bands in the spectra are reproducible and could be identified as originating from aromatic species (1,3-disubstituted benzenes). Spectra from all samples (neat and formulated, used and unused) are very similar. Additives (an acid and a phosphinate) present in low concentration (0.10 percent) in the formulated fluid are not detected. This instrument appears to be a viable tool in helping to identify lubricant components separated by liquid chromatography.

  18. Light-scattering study of the glass transition in lubricants

    Science.gov (United States)

    Alsaad, M. A.; Winer, W. O.; Medina, F. D.; Oshea, D. C.

    1977-01-01

    The sound velocity of four lubricants has been measured as a function of temperature and pressure using Brillouin scattering. A change in slope of the velocity as a function of temperature or pressure allowed the determination of the glass transition temperature and pressure. The glass transition data were used to construct a phase diagram for each lubricant. The data indicate that the glass transition temperature increased with pressure at a rate which ranged from 120 to 200 C/GPa. The maximum pressure attained was 0.69 GPa and the temperature range was from 25 to 100 C.

  19. Investigation on Capability of Reaming Process using Minimal Quantity Lubrication

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Tosello, Guido; Piska, Miroslav

    2008-01-01

    An investigation on reaming using minimal quantity lubrication (MQL) was carried out with the scope of documenting process capability using a metrological approach. Reaming tests were carried out on austenitic stainless steel, using HSS reamers with different cutting data and lubrication conditions...... depth of cut was employed. The suitability of MQL for reaming was proven under the investigated process conditions, concerning both the quality of the machined holes, in terms of geometrical characteristics and surface finishing, and the process quality, with respect to reaming torque and thrust, along...

  20. Thermodynamic chemical energy transfer mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium chemical reactions

    International Nuclear Information System (INIS)

    Roh, Heui-Seol

    2015-01-01

    Chemical energy transfer mechanisms at finite temperature are explored by a chemical energy transfer theory which is capable of investigating various chemical mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium. Gibbs energy fluxes are obtained as a function of chemical potential, time, and displacement. Diffusion, convection, internal convection, and internal equilibrium chemical energy fluxes are demonstrated. The theory reveals that there are chemical energy flux gaps and broken discrete symmetries at the activation chemical potential, time, and displacement. The statistical, thermodynamic theory is the unification of diffusion and internal convection chemical reactions which reduces to the non-equilibrium generalization beyond the quasi-equilibrium theories of migration and diffusion processes. The relationship between kinetic theories of chemical and electrochemical reactions is also explored. The theory is applied to explore non-equilibrium chemical reactions as an illustration. Three variable separation constants indicate particle number constants and play key roles in describing the distinct chemical reaction mechanisms. The kinetics of chemical energy transfer accounts for the four control mechanisms of chemical reactions such as activation, concentration, transition, and film chemical reactions. - Highlights: • Chemical energy transfer theory is proposed for non-, quasi-, and equilibrium. • Gibbs energy fluxes are expressed by chemical potential, time, and displacement. • Relationship between chemical and electrochemical reactions is discussed. • Theory is applied to explore nonequilibrium energy transfer in chemical reactions. • Kinetics of non-equilibrium chemical reactions shows the four control mechanisms

  1. Vaporization of liquid Pb-Li eutectic alloy from 1000K to 1200K - A high temperature mass spectrometric study

    Science.gov (United States)

    Jain, U.; Mukherjee, A.; Dey, G. K.

    2017-09-01

    Liquid lead-lithium eutectic will be used as a coolant in fusion reactor blanket loop. Vapor pressure of the eutectic is an important parameter to accurately predict its in-loop behavior. Past measurements of vapor pressure of the eutectic relied on indirect methods. In this paper, we report for the first time the in-situ vaporization behavior of the liquid alloy between 1042 and 1176 K by Knudsen effusion mass spectrometry (KEMS). It was seen that the vaporization occurred by independent evaporation of lead and lithium. No complex intermetallic vapor was seen in the mass spectra. The partial pressures and enthalpy of vaporization of Pb and Li were evaluated directly from the measured ion intensities formed from the equilibrium vapor over the alloy. The activity of Li over a temperature range of 1042-1176 K was found to be 4.8 × 10-5 to that of pure Li, indicating its very low activity in the alloy.

  2. Vapor condensation device

    International Nuclear Information System (INIS)

    Sakurai, Manabu; Hirayama, Fumio; Kurosawa, Setsumi; Yoshikawa, Jun; Hosaka, Seiichi.

    1992-01-01

    The present invention enables to separate and remove 14 C as CO 3 - ions without condensation in a vapor condensation can of a nuclear facility. That is, the vapor condensation device of the nuclear facility comprises (1) a spray pipe for spraying an acidic aqueous solution to the evaporation surface of an evaporation section, (2) a spray pump for sending the acidic aqueous solution to the spray pipe, (3) a tank for storing the acidic aqueous solution, (4) a pH sensor for detecting pH of the evaporation section, (5) a pH control section for controlling the spray pump, depending on the result of the detection of the pH sensor. With such a constitution, the pH of liquid wastes on the vaporization surface is controlled to 7 by spraying an aqueous solution of dilute sulfuric acid to the evaporation surface, thereby enabling to increase the transfer rate of 14 C to condensates to 60 to 70%. If 14 C is separated and removed as a CO 2 gas from the evaporation surface, the pH of the liquid wastes returns to the alkaline range of 9 to 10 and the liquid wastes are returned to a heating section. The amount of spraying the aqueous solution of dilute sulfuric acid can be controlled till the pH is reduced to 5. (I.S.)

  3. The vapor pressures of explosives

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-05

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

  4. Solid lubricant mass contact transfer technology usage for vacuum ball bearings longevity increasing

    Science.gov (United States)

    Arzymatov, B.; Deulin, E.

    2016-07-01

    A contact mass transfer technological method of solid lubricant deposition on components of vacuum ball bearings is presented. Physics-mathematical model of process contact mass transfer is being considered. The experimental results of ball bearings covered with solid lubricant longevity in vacuum are presented. It is shown that solid lubricant of contact mass transfer method deposition is prospective for ball bearing longevity increasing.

  5. Micro-Plasto-Hydrodynamic Lubrication a Fundamental Mechanism in Cold Rolling

    DEFF Research Database (Denmark)

    Laugier, Maxime; Boman, Romain; Legrand, Nicolas

    2014-01-01

    This paper presents recent investigations in Micro-Plasto-Hydrodynamic (MPH) lubrication. Industrial evidences of the existence of MPH lubrication mechanism for cold rolling processes are presented. A new lubrication model developed for strip drawing processes is then applied to predict the MPH...

  6. Lubrication of soft and hard interfaces with thermo-responsive F127 hydrogel

    DEFF Research Database (Denmark)

    Røn, Troels; Chronakis, Ioannis S.; Lee, Seunghwan

    2014-01-01

    of F127-20 also displayed varying lubricating properties, both in the lubricating mechanism and efficacy, as a function of temperature, speed and tribopairs. F127-20 was most effective in lubricating a soft interface (PDMSePDMS) based on its gel-forming properties in 22.5-60 °C and feasible formation...

  7. 21 CFR 178.3910 - Surface lubricants used in the manufacture of metallic articles.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Surface lubricants used in the manufacture of... lubricants used in the manufacture of metallic articles. The substances listed in this section may be safely used in surface lubricants employed in the manufacture of metallic articles that contact food, subject...

  8. Fundamental functions in equilibrium thermodynamics

    NARCIS (Netherlands)

    Horst, H.J. ter

    In the standard presentations of the principles of Gibbsian equilibrium thermodynamics one can find several gaps in the logic. For a subject that is as widely used as equilibrium thermodynamics, it is of interest to clear up such questions of mathematical rigor. In this paper it is shown that using

  9. CFD analysis of laboratory scale phase equilibrium cell operation

    Science.gov (United States)

    Jama, Mohamed Ali; Nikiforow, Kaj; Qureshi, Muhammad Saad; Alopaeus, Ville

    2017-10-01

    For the modeling of multiphase chemical reactors or separation processes, it is essential to predict accurately chemical equilibrium data, such as vapor-liquid or liquid-liquid equilibria [M. Šoóš et al., Chem. Eng. Process.: Process Intensif. 42(4), 273-284 (2003)]. The instruments used in these experiments are typically designed based on previous experiences, and their operation verified based on known equilibria of standard components. However, mass transfer limitations with different chemical systems may be very different, potentially falsifying the measured equilibrium compositions. In this work, computational fluid dynamics is utilized to design and analyze laboratory scale experimental gas-liquid equilibrium cell for the first time to augment the traditional analysis based on plug flow assumption. Two-phase dilutor cell, used for measuring limiting activity coefficients at infinite dilution, is used as a test case for the analysis. The Lagrangian discrete model is used to track each bubble and to study the residence time distribution of the carrier gas bubbles in the dilutor cell. This analysis is necessary to assess whether the gas leaving the cell is in equilibrium with the liquid, as required in traditional analysis of such apparatus. Mass transfer for six different bio-oil compounds is calculated to determine the approach equilibrium concentration. Also, residence times assuming plug flow and ideal mixing are used as reference cases to evaluate the influence of mixing on the approach to equilibrium in the dilutor. Results show that the model can be used to predict the dilutor operating conditions for which each of the studied gas-liquid systems reaches equilibrium.

  10. CFD analysis of laboratory scale phase equilibrium cell operation.

    Science.gov (United States)

    Jama, Mohamed Ali; Nikiforow, Kaj; Qureshi, Muhammad Saad; Alopaeus, Ville

    2017-10-01

    For the modeling of multiphase chemical reactors or separation processes, it is essential to predict accurately chemical equilibrium data, such as vapor-liquid or liquid-liquid equilibria [M. Šoóš et al., Chem. Eng. Process Intensif. 42(4), 273-284 (2003)]. The instruments used in these experiments are typically designed based on previous experiences, and their operation verified based on known equilibria of standard components. However, mass transfer limitations with different chemical systems may be very different, potentially falsifying the measured equilibrium compositions. In this work, computational fluid dynamics is utilized to design and analyze laboratory scale experimental gas-liquid equilibrium cell for the first time to augment the traditional analysis based on plug flow assumption. Two-phase dilutor cell, used for measuring limiting activity coefficients at infinite dilution, is used as a test case for the analysis. The Lagrangian discrete model is used to track each bubble and to study the residence time distribution of the carrier gas bubbles in the dilutor cell. This analysis is necessary to assess whether the gas leaving the cell is in equilibrium with the liquid, as required in traditional analysis of such apparatus. Mass transfer for six different bio-oil compounds is calculated to determine the approach equilibrium concentration. Also, residence times assuming plug flow and ideal mixing are used as reference cases to evaluate the influence of mixing on the approach to equilibrium in the dilutor. Results show that the model can be used to predict the dilutor operating conditions for which each of the studied gas-liquid systems reaches equilibrium.

  11. VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

    Energy Technology Data Exchange (ETDEWEB)

    Eric M. Suuberg; Vahur Oja

    1997-07-01

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

  12. Calculation of simultaneous chemical and phase equilibrium by the methodof Lagrange multipliers

    DEFF Research Database (Denmark)

    Tsanas, Christos; Stenby, Erling Halfdan; Yan, Wei

    2017-01-01

    iteration in the inner loop and non-ideality updated in the outer loop, thus giving an overall linear convergence rate. Stability analysis is used to introduce additional phases sequentially so as to obtain the final multiphase solution. The procedure was successfully tested on vapor-liquid equilibrium (VLE...

  13. A Simple System for Observing Dynamic Phase Equilibrium via an Inquiry-Based Laboratory or Demonstration

    Science.gov (United States)

    Cloonan, Carrie A.; Andrew, Julie A.; Nichol, Carolyn A.; Hutchinson, John S.

    2011-01-01

    This article describes an activity that can be used as an inquiry-based laboratory or demonstration for either high school or undergraduate chemistry students to provide a basis for understanding both vapor pressure and the concept of dynamic phase equilibrium. The activity includes a simple setup to create a closed system of only water liquid and…

  14. Phase equilibrium modeling of gas hydrate systems for CO2 capture

    DEFF Research Database (Denmark)

    Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens

    2012-01-01

    to form from vapor phases with initial mole fractions of CO2 at or above 0.15.The two models are validated against mixed hydrate equilibrium data found in literature. Both dissociation pressures and hydrate compositions are considered in the validation process.With the fitted parameters, Model I predicts...

  15. A Multiperiod Equilibrium Pricing Model

    Directory of Open Access Journals (Sweden)

    Minsuk Kwak

    2014-01-01

    Full Text Available We propose an equilibrium pricing model in a dynamic multiperiod stochastic framework with uncertain income. There are one tradable risky asset (stock/commodity, one nontradable underlying (temperature, and also a contingent claim (weather derivative written on the tradable risky asset and the nontradable underlying in the market. The price of the contingent claim is priced in equilibrium by optimal strategies of representative agent and market clearing condition. The risk preferences are of exponential type with a stochastic coefficient of risk aversion. Both subgame perfect strategy and naive strategy are considered and the corresponding equilibrium prices are derived. From the numerical result we examine how the equilibrium prices vary in response to changes in model parameters and highlight the importance of our equilibrium pricing principle.

  16. Non-equilibrium phase transitions

    CERN Document Server

    Henkel, Malte; Lübeck, Sven

    2009-01-01

    This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.

  17. Decomposition of atmospheric water content into cluster contributions based on theoretical association equilibrium constants

    International Nuclear Information System (INIS)

    Slanina, Z.

    1987-01-01

    Water vapor is treated as an equilibrium mixture of water clusters (H 2 O)/sub i/ using quantum-chemical evaluation of the equilibrium constants of water associations. The model is adapted to the conditions of atmospheric humidity, and a decomposition algorithm is suggested using the temperature and mass concentration of water as input information and used for a demonstration of evaluation of the water oligomer populations in the Earth's atmosphere. An upper limit of the populations is set up based on the water content in saturated aqueous vapor. It is proved that the cluster population in the saturated water vapor, as well as in the Earth's atmosphere for a typical temperature/humidity profile, increases with increasing temperatures

  18. Hybrid n-Alkylamine Intercalated Layered Titanates for Solid Lubrication

    NARCIS (Netherlands)

    Gonzalez Rodriguez, P.; Yuan, H.; van den Nieuwenhuijzen, Karin Jacqueline Huberta; Lette, W.; Schipper, Dirk J.; ten Elshof, Johan E.

    2016-01-01

    The intercalation of different primary n-alkylamines in the structure of a layered titanate of the lepidocrocite type (H1.07Ti1.73O4) for application in high-temperature solid lubrication is reported. The intercalation process of the amines was explored by means of in situ small-angle X-ray

  19. Bioinspired lubricating films of cellulose nanofibrils and hyaluronic acid.

    Science.gov (United States)

    Valle-Delgado, Juan José; Johansson, Leena-Sisko; Österberg, Monika

    2016-02-01

    The development of materials that combine the excellent mechanical strength of cellulose nanofibrils (CNF) with the lubricating properties of hyaluronic acid (HA) is a new, promising approach to cartilage implants not explored so far. A simple, solvent-free method to produce a very lubricating, strong cellulosic material by covalently attaching HA to the surface of CNF films is described in this work. A detailed analysis of the tribological properties of the CNF films with and without HA is also presented. Surface and friction forces at micro/nanoscale between model hard surfaces (glass microspheres) and the CNF thin films were measured using an atomic force microscope and the colloid probe technique. The effect of HA attachment, the pH and the ionic strength of the aqueous medium on the forces was examined. Excellent lubrication was observed for CNF films with HA attached in conditions where the HA layer was highly hydrated. These results pave the way for the development of new nanocellulose-based materials with good lubrication properties that could be used in biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. A new Friction and Lubrication Test for Cold Forging

    DEFF Research Database (Denmark)

    Bay, Niels; Wibom, Ole; Aalborg Nielsen, J

    1995-01-01

    This paper presents a new friction and lubrication test for cold forging. The test allows controlled variation of the surface expansion in the range 0-2000%, the tool temperature in the range 20-270°C and the sliding length between 0 and infinite. Friction is decreasing with increasing temperature...

  1. Environmentally Benign Lubricant Systems For Cold, Warm And Hot Forging

    DEFF Research Database (Denmark)

    Bay, Niels

    2010-01-01

    paper gives an overview of these efforts substituting environmentally hazardous lubricants in cold, warm and hot forging. The paper is an extract of the keynote paper [3] written by the author together with eight co-authors referring to collected papers and other information from more than 30 different...

  2. Evaluation of lubricity of methanolic extract of mango (Mangifera ...

    African Journals Online (AJOL)

    Methanolic extract of mango seed oil (Mangifera Indica) was evaluated for suitability as lubricant for machini-ng mild steel at various speeds, feeds and depths of cut. The coefficient of friction between the tool and chip in- dicated that the methanolic extract reduced friction between the tool and work piece. The oil also ...

  3. Organic-Modified Silver Nanoparticles as Lubricant Additives.

    Science.gov (United States)

    Kumara, Chanaka; Luo, Huimin; Leonard, Donovan N; Meyer, Harry M; Qu, Jun

    2017-10-25

    Advanced lubrication is essential in human life for improving mobility, durability, and efficiency. Here we report the synthesis, characterization, and evaluation of two groups of oil-suspendable silver nanoparticles (NPs) as candidate lubricant additives. Two types of thiolated ligands, 4-(tert-butyl)benzylthiol (TBBT) and dodecanethiol (C12), were used to modify Ag NPs in two size ranges, 1-3 and 3-6 nm. The organic surface layer successfully suspended the Ag NPs in a poly-alpha-olefin (PAO) base oil with concentrations up to 0.19-0.50 wt %, depending on the particle type. Use of the Ag NPs in the base oil reduced friction by up to 35% and wear by up to 85% in boundary lubrication. The two TBBT-modified NPs produced a lower friction coefficient than the C12-modified one, while the two larger NPs (3-6 nm) had better wear protection than the smaller one (1-3 nm). Results suggested that the molecular structure of the organic ligand might have a dominant effect on the friction behavior, while the NP size could be more influential in the wear protection. No mini-ball-bearing or surface smoothening effects were observed in the Stribeck scans. Instead, the wear protection in boundary lubrication was attributed to the formation of a silver-rich 50-100 nm thick tribofilm on the worn surface, as revealed by morphology examination and composition analysis from both the top surface and cross section.

  4. Lubrication of the Human Ankle Joint in Walking

    Czech Academy of Sciences Publication Activity Database

    Hlaváček, Miroslav

    2010-01-01

    Roč. 132, č. 1 (2010), s. 1-8 ISSN 0742-4787 R&D Projects: GA ČR(CZ) GA103/07/0043 Institutional research plan: CEZ:AV0Z20710524 Keywords : articular cartilage * human ankle joint * lubrication * walking Subject RIV: JJ - Other Materials Impact factor: 0.449, year: 2010

  5. Development of a quantitative lubricant test for deep drawing

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2004-01-01

    A tribological test for deep drawing has been developed by which the performance of lubricants may be evaluated quantitatively measuring the maximum backstroke force on the punch due to sliding friction between tool and work piece surface. The forming force is found not to give useful information...

  6. Biodegradability of unused lubricating brake fluids in fresh and ...

    African Journals Online (AJOL)

    The biodegradability of four unused lubricating brake fluids (Total brake fluid, Allied brake fluid, Oando brake fluid and Ate brake fluid) was carried out in fresh and marine water obtained from Isiokpo stream and Bonny river of the Niger Delta, South South Nigeria. Biodegradability, of the brake fluids were obtained after a 56 ...

  7. Numerical analysis of hydrodynamic journal bearings lubricated with ferrofluid

    NARCIS (Netherlands)

    Montazeri, H.

    2008-01-01

    The current work focuses on studying the hydrodynamic characteristics of flow in journal bearings lubricated with ferrofluid. The bearing has an infinite length and operates under incompressible laminar flow and steady conditions. Assuming linear behaviour for the magnetic material of the

  8. Impact of Water on the Rheology of Lubricating Greases

    NARCIS (Netherlands)

    Cyriac, F.; Lugt, Pieter Martin; Bosman, Rob

    2016-01-01

    The operational life of bearings is often determined by the performance of the lubricating grease. The consistency of the grease prevents it from leaking out of the bearing and provides good sealing properties. The possible ingress of water into the bearing will have a considerable impact not only

  9. Base Oil-Extreme Pressure Additive Synergy in Lubricants

    Science.gov (United States)

    Extreme pressure (EP) additives are those containing reactive elements such as sulfur, phosphorus, and chlorine. In lubrication processes that occur under extremely severe conditions (e.g., high pressure and/or slow speed), these elements undergo chemical reactions generating new materials (tribofi...

  10. On the design of lubricant free piston compressors

    NARCIS (Netherlands)

    Owczarek, P.

    2010-01-01

    This thesis describes the development on long lifetime and an efficient piston compressor operating in a clean environment where oil lubrication must be excluded. Particularly in cooling systems including cryocoolers the presence of oil is a well known problem. A growing number of applications of

  11. Analysis of BJ493 diesel engine lubrication system properties

    Science.gov (United States)

    Liu, F.

    2017-12-01

    The BJ493ZLQ4A diesel engine design is based on the primary model of BJ493ZLQ3, of which exhaust level is upgraded to the National GB5 standard due to the improved design of combustion and injection systems. Given the above changes in the diesel lubrication system, its improved properties are analyzed in this paper. According to the structures, technical parameters and indices of the lubrication system, the lubrication system model of BJ493ZLQ4A diesel engine was constructed using the Flowmaster flow simulation software. The properties of the diesel engine lubrication system, such as the oil flow rate and pressure at different rotational speeds were analyzed for the schemes involving large- and small-scale oil filters. The calculated values of the main oil channel pressure are in good agreement with the experimental results, which verifies the proposed model feasibility. The calculation results show that the main oil channel pressure and maximum oil flow rate values for the large-scale oil filter scheme satisfy the design requirements, while the small-scale scheme yields too low main oil channel’s pressure and too high. Therefore, application of small-scale oil filters is hazardous, and the large-scale scheme is recommended.

  12. Re-Refining of Waste Lubricating Oil by Solvent Extraction

    Directory of Open Access Journals (Sweden)

    Hassan Ali Durrani

    2011-04-01

    Full Text Available Re-refining of waste lubricating oil by solvent extraction is one of the potential techniques. The advantages of solvent extraction technique practically offers from environmental and economic points of view have received due attention. In this paper selection of composite solvent and technique to upgrade the used lubricant oil into base oil has been made. The composite solvent 2-propanol, 1-butanol and butanone have two alcohols that make a binary system reasonably effective. This work also attempts to study the performance of the composite solvent in the extraction process for recovering waste lubricating oil. The key parameters considered were vacuum pressure, temperature and the weight ratio of solvent to waste lubricating oil. The performance was investigated on the PSR (Percentage Sludge Removal and POL (Percent Oil Loss. The best results were obtained using composite solvent 25% 2-propanol, 37% 1-butanol and 38% butanone by a solvent to oil ratio of 6:1 at vacuum pressure 600mmHg and distillation temperature 250oC. The vacuum distilled oil pretreated with the composite solvents was matched to the standard base oil 500N and 150N, found in close agreement and could be used for similar purpose.

  13. Direct observation of lubricant additives using tomography techniques

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yunyun [Department of Materials Science and Engineering, Texas A& M University, College Station, Texas 77843 (United States); Sanchez, Carlos [Mechanical Engineering, Texas A& M University, College Station, Texas 77843 (United States); Parkinson, Dilworth Y. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Liang, Hong, E-mail: hliang@tamu.edu [Department of Materials Science and Engineering, Texas A& M University, College Station, Texas 77843 (United States); Mechanical Engineering, Texas A& M University, College Station, Texas 77843 (United States)

    2016-07-25

    Lubricants play important roles in daily activities such as driving, walking, and cooking. The current understanding of mechanisms of lubrication, particularly in mechanical systems, has been limited by the lack of capability in direct observation. Here, we report an in situ approach to directly observe the motion of additive particles in grease under the influence of shear. Using the K-edge tomography technique, it is possible to detect particular additives in a grease and observe their distribution through 3D visualization. A commercial grease as a reference was studied with and without an inorganic additive of Fe{sub 3}O{sub 4} microparticles. The results showed that it was possible to identify these particles and track their movement. Under a shear stress, Fe{sub 3}O{sub 4} particles were found to adhere to the edge of calcium complex thickeners commonly used in grease. Due to sliding, the grease formed a film with increased density. This approach enables in-line monitoring of a lubricant and future investigation in mechanisms of lubrication.

  14. Phase and viscosity behaviour of refrigerant-lubricant mixtures

    DEFF Research Database (Denmark)

    Cisneros, Sergio; Garcia, J.; Fernandez, J.

    2005-01-01

    , mainly as a function of the molecular asymmetry. This also has a profound effect in the mixture transport properties. Thus, in this work the general aspects of phase and viscosity behaviour linked to the type of asymmetry found in refrigerant-lubricant mixtures are discussed in the context of phase...

  15. Microstructural modelling and lubrication study during zirconium alloy hot extrusion

    International Nuclear Information System (INIS)

    Gaudout, B.

    2009-01-01

    Using torsion tests (with strain rate jumps) and an experimental hot mini-extrusion apparatus, several samples zirconium alloy have been deformed: Zircaloy-4 (high α range) and Zr-1Nb (α + β domain). The fragmentation of the microstructure and post-dynamic grain growth have been examined. The main difference between these two alloys is that Zr-1Nb does not show grain growth during a heat treatment within the α + β domain after hot deformation. The recrystallization volume fraction has been measured on extruded samples with or without heat treatment. These rheological and microstructural data have been used to determine the parameters of a microstructural model including: a work-hardening model (Laaasraoui/Jonas), a continuous dynamic recrystallization model (Gourdet/Montheillet) and a grain growth model. This model leads to a good prediction of recrystallization volume fraction for Zircaloy-4 extrusion. However, the Zr-1Nb model cannot be validated because of the difficulty to observe deformed microstructures. Extrusion process is lubricated with a solid film. Trapping tests show that this lubricant is thermoviscoplastic. Friction along the container and several observations show the lubrication is not realized by a continuous film. Indeed, the heterogeneousness of deformation of these alloys causes a rupture of the lubricant film. Experiments and numerical simulations show that the radial gradient of axial displacement is affected by friction but also by stress softening of the alloys. (author)

  16. [Lubricant-free piston compressors for mechanized medical instruments].

    Science.gov (United States)

    Sabitov, V Kh; Repin, V A; Kil'kinov, A A

    1988-01-01

    Piston compressor without lubrication with air blow to packing rings by plunger, disposed in subpiston space, is recommended as the basic scheme of construction of a power supply unit for medical pneumatic tooling. The construction reduces a leak of the compressive medium, increasing the efficiency of a compressor and seal reliability.

  17. Multilayered antifriction nanostraction covering for lubrication in the tribocoupling

    Directory of Open Access Journals (Sweden)

    Vladimir KOLESNIKOV

    2010-01-01

    Full Text Available In article principles of creation of a new way of the lubrication a wheel-rail tribosystem by drawing on a lateral side of a rail head of a multilayered antifriction nanostructurial covering possessing property of blocking negative segregation phenomena in metals of a wheel and a rail are considered.

  18. Making Self-Lubricating Parts By Powder Metallurgy

    Science.gov (United States)

    Sliney, Harold E.; Dellacorte, Christopher

    1990-01-01

    Compositions and parameters of powder-metallurgical fabrication processes determined for new class of low-friction, low-wear, self-lubricating materials. Used in oxidizing or reducing atmospheres in bearings and seals, at temperatures from below 25 degrees C to as high as 900 degrees C. Thick parts made with minimal waste.

  19. Lubrication of the human ankle joint in running

    Czech Academy of Sciences Publication Activity Database

    Hlaváček, Miroslav

    2009-01-01

    Roč. 3, č. 5 (2009), s. 619-626 ISSN 1970-8734 R&D Projects: GA ČR(CZ) GA103/07/0043 Institutional research plan: CEZ:AV0Z20710524 Keywords : human ankle joint * lubrication * running Subject RIV: JJ - Other Materials

  20. Squeezing molecularly thin alkane lubrication films: Layering transistions and wear

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, V. N.; Persson, B. N. J.

    2004-01-01

    The properties of alkane lubricants confined between two approaching solids are investigated by a model that accounts for the curvature and the elastic properties of the solid surfaces. We consider linear alkane molecules of different chain lengths, C(3)H(8); C(4)H(10); C(8)H(18); C(9)H(20); C(10)H...

  1. The Lubricant Properties of LUBRITAB | Onyechi | Journal of ...

    African Journals Online (AJOL)

    The effect of the lubricants on tablet hardness, friability, disintegration and dissolution rate were also determined. Tablets containing LUBRITAB at a concentration level of 3 - 4 (% w/w) gave values of unit ejection force comparable with those of tablets containing 2% magnesium stearate. The tablets containing LUBRITAB ...

  2. Non-equilibrium supramolecular polymerization.

    Science.gov (United States)

    Sorrenti, Alessandro; Leira-Iglesias, Jorge; Markvoort, Albert J; de Greef, Tom F A; Hermans, Thomas M

    2017-09-18

    Supramolecular polymerization has been traditionally focused on the thermodynamic equilibrium state, where one-dimensional assemblies reside at the global minimum of the Gibbs free energy. The pathway and rate to reach the equilibrium state are irrelevant, and the resulting assemblies remain unchanged over time. In the past decade, the focus has shifted to kinetically trapped (non-dissipative non-equilibrium) structures that heavily depend on the method of preparation (i.e., pathway complexity), and where the assembly rates are of key importance. Kinetic models have greatly improved our understanding of competing pathways, and shown how to steer supramolecular polymerization in the desired direction (i.e., pathway selection). The most recent innovation in the field relies on energy or mass input that is dissipated to keep the system away from the thermodynamic equilibrium (or from other non-dissipative states). This tutorial review aims to provide the reader with a set of tools to identify different types of self-assembled states that have been explored so far. In particular, we aim to clarify the often unclear use of the term "non-equilibrium self-assembly" by subdividing systems into dissipative, and non-dissipative non-equilibrium states. Examples are given for each of the states, with a focus on non-dissipative non-equilibrium states found in one-dimensional supramolecular polymerization.

  3. Synthetics, mineral oils, and bio-based lubricants chemistry and technology

    CERN Document Server

    Rudnick, Leslie R

    2005-01-01

    As the field of tribology has evolved, the lubrication industry is also progressing at an extraordinary rate. Updating the author's bestselling publication, Synthetic Lubricants and High-Performance Functional Fluids, this book features the contributions of over 60 specialists, ten new chapters, and a new title to reflect the evolving nature of the field: Synthetics, Mineral Oils, and Bio-Based Lubricants: Chemistry and Technology. The book contains chapters on all major lubricant fluids used in a wide range of applications. For each type of lubricant, the authors discuss the historical develo

  4. Lubrication analysis of the journal bearing in the main coolant pump of SMART

    International Nuclear Information System (INIS)

    Lee, J. S.; Park, J. S.; Kim, J. H.; Kim, J. I.; Jang, M. H.

    2000-01-01

    Special type journal bearings are installed in the main coolant pump for SMART to support the rotating shaft with proper lubrication. The canned motor type main coolant pumps are arranged vertically on the reactor vessel. The MCP bearings are lubricated with water without external lubricating oil supply. Long bearing with vertical grooves is designed with relatively large bearing clearance to accommodate the long shaft. Lubricational analysis method for journal bearing with vertical grooves in the main coolant pump of SMART is proposed, and lubricational characteristics of the bearings are examined in this paper

  5. Spontaneity and Equilibrium: Why "?G Equilibrium" Are Incorrect

    Science.gov (United States)

    Raff, Lionel M.

    2014-01-01

    The fundamental criteria for chemical reactions to be spontaneous in a given direction are generally incorrectly stated as ?G equilibrium are also misstated as being ?G = 0 or ?A = 0. Following a brief review of the…

  6. Development of solid-gas equilibrium propulsion system for small spacecraft

    Science.gov (United States)

    Chujo, Toshihiro; Mori, Osamu; Kubo, Yuki

    2017-11-01

    A phase equilibrium propulsion system is a kind of cold-gas jet in which the phase equilibrium state of the fuel is maintained in a tank and its vapor is ejected when a valve is opened. One such example is a gas-liquid equilibrium propulsion system that uses liquefied gas as fuel. This system was mounted on the IKAROS solar sail and has been demonstrated in orbit. The system has a higher storage efficiency and a lighter configuration than a high-pressure cold-gas jet because the vapor pressure is lower, and is suitable for small spacecraft. However, the system requires a gas-liquid separation device in order to avoid leakage of the liquid, which makes the system complex. As another example of a phase equilibrium propulsion system, we introduce a solid-gas equilibrium propulsion system, which uses a sublimable substance as fuel and ejects its vapor. This system has an even lower vapor pressure and does not require such a separation device, instead requiring only a filter to keep the solid inside the tank. Moreover, the system is much simpler and lighter, making it more suitable for small spacecraft, especially CubeSat-class spacecraft, and the low thrust of the system allows spacecraft motion to be controlled precisely. In addition, the thrust level can be controlled by controlling the temperature of the fuel, which changes the vapor pressure. The present paper introduces the concept of the proposed system, and describes ejection experiments and its evaluation. The basic function of the proposed system is demonstrated in order to verify its usefulness.

  7. Helical axis stellarator equilibrium model

    International Nuclear Information System (INIS)

    Koniges, A.E.; Johnson, J.L.

    1985-02-01

    An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift

  8. A Comparison of the Computation Times of Thermal Equilibrium and Non-equilibrium Models of Droplet Field in a Two-Fluid Three-Field Model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ik Kyu; Cho, Heong Kyu; Kim, Jong Tae; Yoon, Han Young; Jeong, Jae Jun

    2007-12-15

    A computational model for transient, 3 dimensional 2 phase flows was developed by using 'unstructured-FVM-based, non-staggered, semi-implicit numerical scheme' considering the thermally non-equilibrium droplets. The assumption of the thermally equilibrium between liquid and droplets of previous studies was not used any more, and three energy conservation equations for vapor, liquid, liquid droplets were set up. Thus, 9 conservation equations for mass, momentum, and energy were established to simulate 2 phase flows. In this report, the governing equations and a semi-implicit numerical sheme for a transient 1 dimensional 2 phase flows was described considering the thermally non-equilibrium between liquid and liquid droplets. The comparison with the previous model considering the thermally non-equilibrium between liquid and liquid droplets was also reported.

  9. Solid Lubricants and Coatings for Extreme Environments: State-of-the-Art Survey

    Science.gov (United States)

    Miyoshi, Kazuhisa

    2007-01-01

    An investigation was conducted to survey anticipated requirements for solid lubricants in lunar and Martian environments, as well as the effects of these environments on lubricants and their performance and durability. The success of habitats and vehicles on the Moon and Mars, and ultimately, of the human exploration of and permanent human presence on the Moon and Mars, are critically dependent on the correct and reliable operation of many moving mechanical assemblies and tribological components. The coefficient of friction and lifetime of any lubricant generally vary with the environment, and lubricants have very different characteristics under different conditions. It is essential, therefore, to select the right lubrication technique and lubricant for each mechanical and tribological application. Several environmental factors are hazardous to performance integrity on the Moon and Mars. Potential threats common to both the Moon and Mars are low ambient temperatures, wide daily temperature swings (thermal cycling), solar flux, cosmic radiation, and large quantities of dust. The surface of Mars has the additional challenges of dust storms, winds, and a carbon dioxide atmosphere. Solid lubricants and coatings are needed for lunar and Martian applications, where liquid lubricants are ineffective and undesirable, and these lubricants must perform well in the extreme environments of the Moon, Mars, and space, as well as on Earth, where they will be assembled and tested. No solid lubricants and coatings and their systems currently exist or have been validated that meet these requirements, so new solid lubricants must be designed and validated for these applications.

  10. A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery

    Science.gov (United States)

    DellaCorte, Christopher; Zaldana, Antonio R.; Radil, Kevin C.

    2002-01-01

    Foil air bearings are self-acting hydrodynamic bearings which rely upon solid lubricants to reduce friction and minimize wear during sliding which occurs at start-up and shut-down when surface speeds are too low to allow the formation of a hydrodynamic air film. This solid lubrication is typically accomplished by coating the non-moving foil surface with a thin, soft polymeric film. The following paper introduces a systems approach in which the solid lubrication is provided by a combination of self lubricating shaft coatings coupled with various wear resistant and lubricating foil coatings. The use of multiple materials, each providing different functions is modeled after oil-lubricated hydrodynamic sleeve bearing technology which utilizes various coatings and surface treatments in conjunction with oil lubricants to achieve optimum performance. In this study, room temperature load capacity tests are performed on journal foil air bearings operating at 14,000 rpm. Different shaft and foil coating technologies such as plasma sprayed composites, ceramic, polymer and inorganic lubricant coatings are evaluated as foil bearing lubricants. The results indicate that bearing performance is improved through the individual use of the lubricants and treatments tested. Further, combining several solid lubricants together yielded synergistically better results than any material alone.

  11. The annual cycle of stratospheric water vapor in a general circulation model

    Science.gov (United States)

    Mote, Philip W.

    1995-01-01

    The application of general circulation models (GCM's) to stratospheric chemistry and transport both permits and requires a thorough investigation of stratospheric water vapor. The National Center for Atmospheric Research has redesigned its GCM, the Community Climate Model (CCM2), to enable studies of the chemistry and transport of tracers including water vapor; the importance of water vapor to the climate and chemistry of the stratosphere requires that it be better understood in the atmosphere and well represented in the model. In this study, methane is carried as a tracer and converted to water; this simple chemistry provides an adequate representation of the upper stratospheric water vapor source. The cold temperature bias in the winter polar stratosphere, which the CCM2 shares with other GCM's, produces excessive dehydration in the southern hemisphere, but this dry bias can be ameliorated by setting a minimum vapor pressure. The CCM2's water vapor distribution and seasonality compare favorably with observations in many respects, though seasonal variations including the upper stratospheric semiannual oscillation are generally too small. Southern polar dehydration affects midlatitude water vapor mixing ratios by a few tenths of a part per million, mostly after the demise of the vortex. The annual cycle of water vapor in the tropical and northern midlatitude lower stratosphere is dominated by drying at the tropical tropopause. Water vapor has a longer adjustment time than methane and had not reached equilibrium at the end of the 9 years simulated here.

  12. Determination of Lubricants on Ball Bearings by FT-IR using an Integrating Sphere

    Science.gov (United States)

    Street, K. W.; Pepper, S. V.; Wright, A.

    2003-01-01

    The lifetime determination of space lubricants is done at our facility by accelerated testing. Several micrograms of lubricant are deposited on the surface of a ball by syringing tens of micro liters of dilute lubricant solution. The solvent evaporates and the mass of lubricant is determined by twenty weighings near the balance reliability limit. This process is timely but does not produce a good correlation between the mass of lubricant and the volume of solution applied, as would be expected. The amount of lubricant deposited on a ball can be determined directly by Fourier Transform - Infrared Spectroscopy using an integrating sphere. In this paper, we discuss reasons for choosing this methodology, optimization of quantification conditions and potential applications for the technique. The volume of lubricant solution applied to the ball gives better correlation to the IR intensity than does the weight.

  13. A study on vapor explosions

    International Nuclear Information System (INIS)

    Takagi, N.; Shoji, M.

    1979-01-01

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

  14. Revisiting liquid lubrication methods by means of a fully coupled approach combining plastic deformation and liquid lubrication

    DEFF Research Database (Denmark)

    Üstünyagiz, Esmeray; Christiansen, Peter; Nielsen, Chris Valentin

    2017-01-01

    This paper presents a new approach based on a fully coupled procedure in which the lubricant flow and the plasticdeformation of the metallic material in metal forming are solved simultaneously. The proposed method is an alternativeto conventional modelling techniques which allow studying the effect...... andanalytical model, and by variations in drawing speed. Good agreement is found with the experimental observations....

  15. Use of Textured Surfaces to Mitigate Sliding Friction and Wear of Lubricated and Non-Lubricated Contacts

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL

    2012-03-01

    If properly employed, the placement of three-dimensional feature patterns, also referred to as textures, on relatively-moving, load-bearing surfaces can be beneficial to their friction and wear characteristics. For example, geometric patterns can function as lubricant supply channels or depressions in which to trap debris. They can also alter lubricant flow in a manner that produces thicker load-bearing films locally. Considering the area occupied by solid areas and spaces, textures also change the load distribution on surfaces. At least ten different attributes of textures can be specified, and their combinations offer wide latitude in surface engineering. By employing directional machining and grinding procedures, texturing has been used on bearings and seals for well over a half century, and the size scales of texturing vary widely. This report summarizes past work on the texturing of load-bearing surfaces, including past research on laser surface dimpling of ceramics done at ORNL. Textured surfaces generally show most pronounced effects when they are used in conformal or nearly conformal contacts, like that in face seals. Combining textures with other forms of surface modification and lubrication methods can offer additional benefits in surface engineering for tribology. As the literature and past work at ORNL shows, texturing does not always provide benefits. Rather, the selected pattern and arrangement of features must be matched to characteristics of the proposed application, bearing materials, and lubricants.

  16. Nuclear system vaporization

    International Nuclear Information System (INIS)

    Bougault, R.; Brou, R.; Colin, J.; Cussol, D.; Durand, D.; Le Brun, C.; Lecolley, J.F.; Lopez, O.; Louvel, M.; Nakagawa, T.; Peter, J.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Yuasa-Nakagawa, K.; Wieloch, A.

    1998-01-01

    A particular case of the hot nuclei de-excitation is the total nuclear dislocation into light particles (n, p, d, t, 3 He and α). Such events were first observed at bombarding energies lower than 100 MeV/nucleon due to high detection performances of the INDRA multidetector. The light system Ar + Ni was studied at several bombarding energies ranging from 32 to 95 MeV/nucleon. The events associated to a total vaporization of the system occur above the energy threshold of ∼ 50 MeV/nucleon. A study of the form of these events shows that we have essentially two sources. The excitation energy of these sources may be determined by means of the kinematic properties of their de-excitation products. A preliminary study results in excitation energy values of the order 10 - 14 MeV/nucleon. The theoretical calculation based on a statistical model modified to take into account high excitation energies and excited levels in the lightest nuclei predicts that the vaporization of the two partner nuclei in the Ar + Ni system takes place when the excitation energy exceeds 12 MeV/nucleon what is qualitatively in agreement with the values deduced from calorimetric analysis

  17. Numerical Verification Of Equilibrium Chemistry

    International Nuclear Information System (INIS)

    Piro, Markus; Lewis, Brent; Thompson, William T.; Simunovic, Srdjan; Besmann, Theodore M.

    2010-01-01

    A numerical tool is in an advanced state of development to compute the equilibrium compositions of phases and their proportions in multi-component systems of importance to the nuclear industry. The resulting software is being conceived for direct integration into large multi-physics fuel performance codes, particularly for providing boundary conditions in heat and mass transport modules. However, any numerical errors produced in equilibrium chemistry computations will be propagated in subsequent heat and mass transport calculations, thus falsely predicting nuclear fuel behaviour. The necessity for a reliable method to numerically verify chemical equilibrium computations is emphasized by the requirement to handle the very large number of elements necessary to capture the entire fission product inventory. A simple, reliable and comprehensive numerical verification method is presented which can be invoked by any equilibrium chemistry solver for quality assurance purposes.

  18. Equilibrium ignition for ICF capsules

    International Nuclear Information System (INIS)

    Lackner, K.S.; Colgate, S.A.; Johnson, N.L.; Kirkpatrick, R.C.; Menikoff, R.; Petschek, A.G.

    1993-01-01

    There are two fundamentally different approaches to igniting DT fuel in an ICF capsule which can be described as equilibrium and hot spot ignition. In both cases, a capsule which can be thought of as a pusher containing the DT fuel is imploded until the fuel reaches ignition conditions. In comparing high-gain ICF targets using cryogenic DT for a pusher with equilibrium ignition targets using high-Z pushers which contain the radiation. The authors point to the intrinsic advantages of the latter. Equilibrium or volume ignition sacrifices high gain for lower losses, lower ignition temperature, lower implosion velocity and lower sensitivity of the more robust capsule to small fluctuations and asymmetries in the drive system. The reduction in gain is about a factor of 2.5, which is small enough to make the more robust equilibrium ignition an attractive alternative

  19. On the local equilibrium condition

    International Nuclear Information System (INIS)

    Hessling, H.

    1994-11-01

    A physical system is in local equilibrium if it cannot be distinguished from a global equilibrium by ''infinitesimally localized measurements''. This should be a natural characterization of local equilibrium, but the problem is to give a precise meaning to the qualitative phrase ''infinitesimally localized measurements''. A solution is suggested in form of a Local Equilibrium Condition (LEC), which can be applied to linear relativistic quantum field theories but not directly to selfinteracting quantum fields. The concept of local temperature resulting from LEC is compared to an old approach to local temperature based on the principle of maximal entropy. It is shown that the principle of maximal entropy does not always lead to physical states if it is applied to relativistic quantum field theories. (orig.)

  20. Determination of Lubricant Bulk Modulus in Metal Forming by Means of a Simple Laboratory Test and Inverse FEM Analysis

    DEFF Research Database (Denmark)

    Hafis, S. M.; Christiansen, P.; Martins, P. A. F.

    2016-01-01

    The influence of workpiece surface topography on friction, lubrication and final surface equality in metal forming operations is well known and has been pointed out by many researchers.This is especially the case when liquid lubricants are applied in situations, where increased surface roughness ...... couples lubricant flow with plastic deformation of the metal directly. Results show that the proposed procedure allows determining an approximate bulk modulus for the lubricant.......The influence of workpiece surface topography on friction, lubrication and final surface equality in metal forming operations is well known and has been pointed out by many researchers.This is especially the case when liquid lubricants are applied in situations, where increased surface roughness...... facilitates the lubricant entrainment, pressurization and possible escape by micro-plasto-hydrodynamic lubrication. In order to model these mechanisms an important lubricant propertyd esignated as the bulk modulus is needed for characterizing the compressibility of the lubricant. The present paper describes...

  1. A Strategic-Equilibrium Based

    Directory of Open Access Journals (Sweden)

    Gabriel J. Turbay

    2011-03-01

    Full Text Available The strategic equilibrium of an N-person cooperative game with transferable utility is a system composed of a cover collection of subsets of N and a set of extended imputations attainable through such equilibrium cover. The system describes a state of coalitional bargaining stability where every player has a bargaining alternative against any other player to support his corresponding equilibrium claim. Any coalition in the sable system may form and divide the characteristic value function of the coalition as prescribed by the equilibrium payoffs. If syndicates are allowed to form, a formed coalition may become a syndicate using the equilibrium payoffs as disagreement values in bargaining for a part of the complementary coalition incremental value to the grand coalition when formed. The emergent well known-constant sum derived game in partition function is described in terms of parameters that result from incumbent binding agreements. The strategic-equilibrium corresponding to the derived game gives an equal value claim to all players.  This surprising result is alternatively explained in terms of strategic-equilibrium based possible outcomes by a sequence of bargaining stages that when the binding agreements are in the right sequential order, von Neumann and Morgenstern (vN-M non-discriminatory solutions emerge. In these solutions a preferred branch by a sufficient number of players is identified: the weaker players syndicate against the stronger player. This condition is referred to as the stronger player paradox.  A strategic alternative available to the stronger players to overcome the anticipated not desirable results is to voluntarily lower his bargaining equilibrium claim. In doing the original strategic equilibrium is modified and vN-M discriminatory solutions may occur, but also a different stronger player may emerge that has eventually will have to lower his equilibrium claim. A sequence of such measures converges to the equal

  2. Thermodynamic evolution far from equilibrium

    Science.gov (United States)

    Khantuleva, Tatiana A.

    2018-05-01

    The presented model of thermodynamic evolution of an open system far from equilibrium is based on the modern results of nonequilibrium statistical mechanics, the nonlocal theory of nonequilibrium transport developed by the author and the Speed Gradient principle introduced in the theory of adaptive control. Transition to a description of the system internal structure evolution at the mesoscopic level allows a new insight at the stability problem of non-equilibrium processes. The new model is used in a number of specific tasks.

  3. Relevance of equilibrium in multifragmentation

    International Nuclear Information System (INIS)

    Furuta, Takuya; Ono, Akira

    2009-01-01

    The relevance of equilibrium in a multifragmentation reaction of very central 40 Ca + 40 Ca collisions at 35 MeV/nucleon is investigated by using simulations of antisymmetrized molecular dynamics (AMD). Two types of ensembles are compared. One is the reaction ensemble of the states at each reaction time t in collision events simulated by AMD, and the other is the equilibrium ensemble prepared by solving the AMD equation of motion for a many-nucleon system confined in a container for a long time. The comparison of the ensembles is performed for the fragment charge distribution and the excitation energies. Our calculations show that there exists an equilibrium ensemble that well reproduces the reaction ensemble at each reaction time t for the investigated period 80≤t≤300 fm/c. However, there are some other observables that show discrepancies between the reaction and equilibrium ensembles. These may be interpreted as dynamical effects in the reaction. The usual static equilibrium at each instant is not realized since any equilibrium ensemble with the same volume as that of the reaction system cannot reproduce the fragment observables

  4. Shape characteristics of equilibrium and non-equilibrium fractal clusters.

    Science.gov (United States)

    Mansfield, Marc L; Douglas, Jack F

    2013-07-28

    It is often difficult in practice to discriminate between equilibrium and non-equilibrium nanoparticle or colloidal-particle clusters that form through aggregation in gas or solution phases. Scattering studies often permit the determination of an apparent fractal dimension, but both equilibrium and non-equilibrium clusters in three dimensions frequently have fractal dimensions near 2, so that it is often not possible to discriminate on the basis of this geometrical property. A survey of the anisotropy of a wide variety of polymeric structures (linear and ring random and self-avoiding random walks, percolation clusters, lattice animals, diffusion-limited aggregates, and Eden clusters) based on the principal components of both the radius of gyration and electric polarizability tensor indicates, perhaps counter-intuitively, that self-similar equilibrium clusters tend to be intrinsically anisotropic at all sizes, while non-equilibrium processes such as diffusion-limited aggregation or Eden growth tend to be isotropic in the large-mass limit, providing a potential means of discriminating these clusters experimentally if anisotropy could be determined along with the fractal dimension. Equilibrium polymer structures, such as flexible polymer chains, are normally self-similar due to the existence of only a single relevant length scale, and are thus anisotropic at all length scales, while non-equilibrium polymer structures that grow irreversibly in time eventually become isotropic if there is no difference in the average growth rates in different directions. There is apparently no proof of these general trends and little theoretical insight into what controls the universal anisotropy in equilibrium polymer structures of various kinds. This is an obvious topic of theoretical investigation, as well as a matter of practical interest. To address this general problem, we consider two experimentally accessible ratios, one between the hydrodynamic and gyration radii, the other

  5. Rotor Rolling over a Water-Lubricated Bearing

    Science.gov (United States)

    Shatokhin, V. F.

    2018-02-01

    The article presents the results of studying the effect of forces associated with secondary damping coefficients (gyroscopic forces) on the development of asynchronous rolling of the rotor over a water-lubricated bearing. The damping forces act against the background of other exciting forces in the rotor-supports system, in particular, the exciting forces of contact interaction between the rotor and bearing. The article considers a rotor resting on supports rubbing against the bearing and the occurrence of self-excited vibration in the form of asynchronous roll-over. The rotor supports are made in the form of plain-type water-lubricated bearings. The plain-type bearing's lubrication stiffness and damping forces are determined using the wellknown algorithms taking into account the physical properties of water serving as lubrication of the bearing. The bearing sliding pair is composed of refractory materials. The lubrication layer in such bearings is thinner than that used in oil-lubricated bearings with white metal lining, and there is no white metal layer in waterlubricated bearings. In case of possible deviations from normal operation of the installation, the rotating rotor comes into direct contact with the liner's rigid body. Unsteady vibrations are modeled using a specially developed software package for calculating the vibration of rotors that rub against the turbine (pump) stator elements. The stiffness of the bearing liner with the stator support structure is specified by a dependence in the force-deformation coordinate axes. In modeling the effect of damping forces, the time moment corresponding to the onset of asynchronous rolling-over with growing vibration amplitudes is used as the assessment criterion. With a longer period of time taken for the rolling-over to develop, it becomes possible to take the necessary measures in response to actuation of the equipment set safety system, which require certain time for implementing them. It is shown that the

  6. Heterogeneous equilibrium in mplybdenum-iodine system

    International Nuclear Information System (INIS)

    Klinkova, L.A.

    1983-01-01

    Heterogeneous equilibrium in the Mo-J system is studied to reveal regions of existence of molybdenum iodides, is studied. The investigation is performed for atomic ratio I/Mo=0.02-7.5 in the temperature range of 300-1370 K using methods of thermographic, X-ray phase, chemical and optical analyses of phases quenched after isothermal annealing. It is shown that higher molybdenum iodides (Mo1 4 , MoJ 5 , MoJ 6 ) are thermally unstable compounds and exist in the Mo-J system at low temperatures (360-490 K). Above 470 K higher iodides dissociate up to molybdenum triiodide. MoJ 3 under the pressure of iodine vapors is stable up to 970 K. Molybdenum diiodide is the product of triiodide decomposition and forms in the Mo-J system in the 700-1270 K range. At the J/Mo>>3 ratio the product of triiodide decomposition is MoJsub(2.87) which is thermally unstable up to 570 K, while in iodine atmosphere - up to 1170 K

  7. Framework for simulating droplet vaporization in turbulent flows

    Science.gov (United States)

    Palmore, John; Desjardins, Olivier

    2017-11-01

    A framework for performing direct numerical simulations of droplet vaporization is presented. The work is motivated by spray combustion in engines wherein fuel droplets vaporize in a turbulent gas flow. The framework is built into a conservative finite volume code for simulating low Mach number turbulent multiphase flows. Phase tracking is performed using a discretely conservative geometric volume of fluid method, while the transport of mass fraction and temperature is performed using the BQUICK scheme. Special attention is given to the implementation of transport equations near the interface to ensure the consistency between fluxes of mass, momentum, and scalars. The effect of evaporation on the flow appears as a system of coupled source terms which depend on the local thermodynamic equilibrium between the phases. The sources are implemented implicitly using an unconditionally stable, monotone scheme. Two methodologies for resolving the system's thermodynamic equilibrium are compared for their accuracy, robustness, and computational expense. Verification is performed by comparing results to known solutions in one and three dimensions. Finally, simulations of droplets vaporizing in turbulence are demonstrated, and trends for mass fraction and temperature fields are discussed.

  8. Chemical vapor composites (CVC)

    International Nuclear Information System (INIS)

    Reagan, P.

    1993-01-01

    The Chemical Vapor Composite, CVC trademark , process fabricates composite material by simply mixing particles (powders and or fibers) with CVD reactants which are transported and co-deposited on a hot substrate. A key feature of the CVC process is the control provided by varing the density, geometry (aspect ratio) and composition of the entrained particles in the matrix material, during deposition. The process can fabricate composite components to net shape (± 0.013 mm) on a machined substrate in a single step. The microstructure of the deposit is described and several examples of different types of particles in the matrix are illustrated. Mechanical properties of SiC composite material fabricated with SiC powder and fiber will be presented. Several examples of low cost ceramic composite products will be shown. (orig.)

  9. Iron bromide vapor laser

    Science.gov (United States)

    Sukhanov, V. B.; Shiyanov, D. V.; Trigub, M. V.; Dimaki, V. A.; Evtushenko, G. S.

    2016-03-01

    We have studied the characteristics of a pulsed gas-discharge laser on iron bromide vapor generating radiation with a wavelength of 452.9 nm at a pulse repetition frequency (PRF) of 5-30 kHz. The maximum output power amounted to 10 mW at a PRF within 5-15 kHz for a voltage of 20-25 kV applied to electrodes of the discharge tube. Addition of HBr to the medium produced leveling of the radial profile of emission. Initial weak lasing at a wavelength of 868.9 nm was observed for the first time, which ceased with buildup of the main 452.9-nm line.

  10. Vapor-droplet flow equations

    International Nuclear Information System (INIS)

    Crowe, C.T.

    1975-01-01

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

  11. The Stability of Lubricant Oil Acidity of Biogas Fuelled Engine due to Biogas Desulfurization

    Science.gov (United States)

    Gde Tirta Nindhia, Tjokorda; Wayan Surata, I.; Wardana, Ari

    2017-05-01

    This research is established for the purpose of the understanding the stability of the acidity of lubricant oil in biogas fuelled engine due to the absence of hydrogen sulfide (H2S). As was recognized that other than Methane (CH4), there are also other gas impurities in the biogas such as carbon dioxide (CO2), hydrogen sulfide (H2S), moisture (H2O) and ammonia (NH3). Due to H2S contents in the biogas fuel, the engine was found failure. This is caused by corrosion in the combustion chamber due to increase of lubricant acidity. To overcome this problem in practical, the lubricant is increased the pH to basic level with the hope will be decrease to normal value after several time use. Other method is by installing pH measurement sensor in the engine lubricant so that when lubricant is known turn to be acid, then lubricant replacement should be done. In this research, the effect of biogas desulfurization down to zero level to the acidity of lubricant oil in the four stroke engine was carried out with the hope that neutral lubrication oil to be available during running the engine. The result indicates that by eliminating H2S due desulfurization process, effect on stability and neutrality of pH lubricant. By this method the engine safety can be obtained without often replacement the lubricant oil.

  12. Influence of Cooling Lubricants on the Surface Roughness and Energy Efficiency of the Cutting Machine Tools

    Directory of Open Access Journals (Sweden)

    Jersák J.

    2017-08-01

    Full Text Available The Technical University of Liberec and Brandenburg University of Technology Cottbus-Senftenberg investigated the influence of cooling lubricants on the surface roughness and energy efficiency of cutting machine tools. After summarizing the achieved experimental results, the authors conclude that cooling lubricants extensively influence the cutting temperature, cutting forces and energy consumption. Also, it is recognizable that cooling lubricants affect the cutting tools lifetime and the workpiece surface quality as well. Furthermore, costs of these cooling lubricants and the related environmental burden need to be considered. A current trend is to reduce the amount of lubricants that are used, e.g., when the Minimum Quantity Lubrication (MQL technique is applied. The lubricant or process liquid is thereby transported by the compressed air in the form of an aerosol to the contact area between the tool and workpiece. The cutting process was monitored during testing by the three following techniques: lubricant-free cutting, cutting with the use of a lubricant with the MQL technique, and only utilizing finish-turning and finish-face milling. The research allowed the authors to monitor the cutting power and mark the achieved surface quality in relation to the electrical power consumption of the cutting machine. In conclusions, the coherence between energy efficiency of the cutting machine and the workpiece surface quality regarding the used cooling lubricant is described.

  13. Monitoring of lubrication conditions in journal bearing by acoustic emission

    International Nuclear Information System (INIS)

    Yoon, Dong Jin; Kwon, Oh Yang; Jung, Min Hwa

    1993-01-01

    Systems with journal bearings generally operate in large scale and under severe loading conditions such as steam generator turbines and internal combustion engines, in contrast to the machinery using rolling element bearings. Failure of the bearings in these machinery can result in the system breakdown. To avoid the time consuming repair and considerable economic loss, the detection of incipient failure in journal bearings becomes very important. In this experimental approach, acoustic emission monitoring is employed to the detection of incipient failure caused by intervention of foreign particles most probable in the journal bearing systems. It has been known that the intervention of foreign materials, insufficient lubrication and misassembly etc. are principal factors to cause bearing failure and distress. The experiment was conducted under such designed conditions as inserting alumina particles to the lubrication layer in the simulated journal bearing system. The results showed that acoustic emission could be an effective tool to detect the incipient failure in journal bearings.

  14. Film Thickness and Friction Relationship in Grease Lubricated Rough Contacts

    Directory of Open Access Journals (Sweden)

    David Gonçalves

    2017-08-01

    Full Text Available The relationship between the film generation and the coefficient of friction in grease lubricated contacts was investigated. Ball-on-disc tests were performed under different operating conditions: entrainment speed, lubricant temperature and surface roughness. The tests were performed with fully formulated greases and their base oils. The greases were formulated with different thickener types and also different base oils natures and viscosities. Film thickness measurements were performed in ball-on-glass disc tests, and Stribeck curves were measured in ball-on-steel disc tests with discs of different roughness. The role of the thickener and the base oil nature/viscosity on the film thickness and coefficient of friction was addressed and the greases’ performance was compared based on their formulation.

  15. Immobilisation of alpha contaminated lubricating oils in cement matrix

    International Nuclear Information System (INIS)

    Manohar, Smitha; Sathi Sasidharan, N.; Wattal, P.K.; Shah, N.J.; Chander, Mahesh; Bansal, N.K.

    2000-10-01

    Alpha contaminated lubricating oil wastes are generated from the reprocessing plants and other alpha handling facilities. Incineration of these spent lubricating oils requires specially designed facility to handle the aerosols of actinide oxides released to the off-gases. Hence immobilisation of these wastes into cement matrix could be a viable alternative. Work was therefore initiated to examine the possibility of immobilising such waste in cement matrix with the help of suitable additives. This work led to the selection of sodium hydroxide and silica fumes as additives for their distinct role in immobilization of such waste in cement. The selected formulation was tested extensively both on laboratory scale and full scale for acceptable waste form. The leach test on laboratory scale indicated negligible release of alpha and beta gamma activity after 180 days. This report gives a brief on the formulation of the admixture and its effect on the immobilization of waste. (author)

  16. Preliminary Results of Cleaning Process for Lubricant Contamination

    Science.gov (United States)

    Eisenmann, D.; Brasche, L.; Lopez, R.

    2006-03-01

    Fluorescent penetrant inspection (FPI) is widely used for aviation and other components for surface-breaking crack detection. As with all inspection methods, adherence to the process parameters is critical to the successful detection of defects. Prior to FPI, components are cleaned using a variety of cleaning methods which are selected based on the alloy and the soil types which must be removed. It is also important that the cleaning process not adversely affect the FPI process. There are a variety of lubricants and surface coatings used in the aviation industry which must be removed prior to FPI. To assess the effectiveness of typical cleaning processes on removal of these contaminants, a study was initiated at an airline overhaul facility. Initial results of the cleaning study for lubricant contamination in nickel, titanium and aluminum alloys will be presented.

  17. Preliminary Results of Cleaning Process for Lubricant Contamination

    International Nuclear Information System (INIS)

    Eisenmann, D.; Brasche, L.; Lopez, R.

    2006-01-01

    Fluorescent penetrant inspection (FPI) is widely used for aviation and other components for surface-breaking crack detection. As with all inspection methods, adherence to the process parameters is critical to the successful detection of defects. Prior to FPI, components are cleaned using a variety of cleaning methods which are selected based on the alloy and the soil types which must be removed. It is also important that the cleaning process not adversely affect the FPI process. There are a variety of lubricants and surface coatings used in the aviation industry which must be removed prior to FPI. To assess the effectiveness of typical cleaning processes on removal of these contaminants, a study was initiated at an airline overhaul facility. Initial results of the cleaning study for lubricant contamination in nickel, titanium and aluminum alloys will be presented

  18. Carbon microspheres as ball bearings in aqueous-based lubrication.

    Science.gov (United States)

    St Dennis, J E; Jin, Kejia; John, Vijay T; Pesika, Noshir S

    2011-07-01

    We present an exploratory study on a suspension of uniform carbon microspheres as a new class of aqueous-based lubricants. The surfactant-functionalized carbon microspheres (∼0.1 wt %) employ a rolling mechanism similar to ball bearings to provide low friction coefficients (μ ≈ 0.03) and minimize surface wear in shear experiments between various surfaces, even at high loads and high contact pressures. The size range, high monodispersity, and large yield stress of the C(μsphere), as well as the minimal environmental impact, are all desirable characteristics for the use of a C(μsphere)-SDS suspension as an alternative to oil-based lubricants in compatible devices and machinery.

  19. Turbulent lubrication theory considering the surface roughness effects, 2

    International Nuclear Information System (INIS)

    Hashimoto, Hiromu; Wada, Sanae; Kobayashi, Toshinobu.

    1990-01-01

    This second paper describes an application of the generalized turbulent lubrication theory considering the surface roughness effects, which is developed in the previous paper, to the finite-width journal bearings. In the numerical analysis, the nonlinear equations for the modified turbulence coefficients are simplified to save a computation time within a satisfactory accuracy under the assumption that the shear flow is superior to the pressure flow in the turbulent lubrication films. The numerical results of pressure distribution, Sommerfeld number, attitude angle, friction coefficient and flow rate for the Reynolds number of Re=2000, 5000 and 10000 are indicated in graphic form for various values of relative roughness, and the effects of surface roughness on these static performance characteristics are discussed. Moreover, the eccentricity ratio and attitude angle of the journal bearings with homogeneous rough surface are obtained experimentally for a wide range of Sommerfeld number, and the experimental results are compared with theoretical results. (author)

  20. Validity of the modified Reynolds equation for incompressible active lubrication

    DEFF Research Database (Denmark)

    Cerda Varela, Alejandro Javier; Santos, Ilmar

    2016-01-01

    The modified Reynolds equation for active lubrication has been the cornerstone around which the theoretical investigations regarding actively lubricated bearings have evolved over the years. Introduced originally in 1994, it enables to calculate in a simplified manner the bearing pressure field...... as a function of servovalve controlled pressurized oil injection. This article deals with a preliminary critical review of the simplificatory assumptions that are introduced into the modified Reynolds equation in order to model the phenomena taking place in the interface between the injection nozzle...... and the bearing clearance. The analysis is performed by means of direct comparison of the results of the modified Reynolds equation model versus benchmark CFD calculations, applied to a geometry representative of the system analyzed. The results show that the modified Reynolds equation mathematical simplicity...