Saturated Hydrocarbon Liquids Research Articles

The Fatigue Wear Process of Rubber-Metal Shock Absorbers.

Rubber and rubber-metal vibration isolators are widely used vibration isolation systems in marine applications. For naval application, shock absorber mounting systems must fulfil two functions. The first one supports the suspended mass in the absence of waving or detonation while providing isolation from vibrations and shock impact. In the second case, during the machine operation, it reduces the force of movement to an acceptable value. Moreover, it returns the insulated mass to the position output without plastic deformation or residual buckling after removing shock stresses or harmonic vibrations. The environment in which marine vibration isolators are to be used strongly influences the selection of a shock absorber. The main environmental problem is the temperature range in marine power plants, which ranges from 20 °C to 55 °C. Temperature fluctuations may cause changes in the physical properties of typical vibration/shock insulators. Both rubbers and elastomers used for shock absorbers tend to stiffen, gain low-temperature damping, and soften and lose damping at elevated temperatures. Factors such as moisture, ozone and changes in atmospheric pressure are usually ignored in shipbuilding. The main environmental factors influencing the ageing of insulators are liquid saturated hydrocarbons, i.e., oils, fuels, coolants, etc., which may come into contact with the surface of the insulators. This work presents the results of the research carried out to determine the effect of overload and the impact of petroleum products on the materials of metal-rubber shock absorbers made of three different rubbers and one polyurethane mixture. For each of the materials, shock absorbers with three different degrees of hardness were tested.

Evolution and organic geochemical significance of bicyclic sesquiterpanes in pyrolysis simulation experiments on immature organic-rich mudstone

Sesquiterpanes are ubiquitous components of crude oils and ancient sediments. Liquid saturated hydrocarbons from simulated pyrolysis experiments on immature organic-rich mudstone collected from the Lower Cretaceous Hesigewula Sag were analyzed by gas chromatography–mass spectrometry (GC–MS). C14 bicyclic sesquiterpanes, namely, 8β(H)-drimane, 8β(H)-homodrimane, and 8α(H)-homodrimane were detected and identified on basis of their diagnostic fragment ions (m/z 123, 179, 193, and 207), and previously published mass spectra data, and these bicyclic sesquiterpanes presented relatively regular characteristics in their thermal evolution. The ratios 8β(H)-drimane/8β(H)-homodrimane, 8β(H)-homodrimane/8α(H)-homodrimane, and 8β(H)-drimane/8α(H)-homodrimane all show a clear upward trend with increasing temperature below the temperature turning point. Thus, all these ratios can be used as evolution indexes of source rocks in the immature–low-maturity stage. However, the last two ratios may be more suitable than the first ratio as valid parameters for measuring the extent of thermal evolution of organic matter in the immature–low-maturity stage because their change amplitude with increasing temperature is more obvious.

A more eco-friendly synthesis of flocculants to treat wastewaters using health-friendly solvents

The main objective of this work was to investigate the possibility of producing new polyelectrolytes (flocculants) synthesized using health-friendly ingredients. A well-known copolymer used in water treatment, poly(acrylamide-co-2-(acryloyloxy)ethyltrimethyl ammonium chloride), was prepared by inverse-emulsion polymerization using new alternative organic phases. Specifically, three different purified oils of liquid saturated hydrocarbons with high boiling point and high purity were tested as synthesis media in the development of copolymers with different charge densities. In all of these oils, the toxic polycyclic aromatics and the heavy metals were not present. The polyelectrolytes were characterized in terms of shear viscosity, hydrodynamic diameter, molecular weight, zeta potential, intrinsic viscosity, and chemical composition (13C NMR and FTIR). Final results revealed the success of the application of the new health-friendly formulation in the polymerization to produce polyelectrolytes and, additionally, the polymers produced had good flocculation efficiency in two different real industrial effluents.

Hyperthermal Reactions of O and O2 with a Hydrocarbon Surface: Direct C−C Bond Breakage by O and H-Atom Abstraction by O2

A C-C bond-breaking reaction has been observed when a beam containing hyperthermal oxygen was directed at a continuously refreshed saturated hydrocarbon liquid (squalane) surface. The dynamics of this C-C bond-breaking reaction have been investigated by monitoring time-of-flight and angular distributions of the volatile product, OCH3 or H2CO. The primary product is believed to be the methoxy radical, OCH3, but if this radical is highly internally excited, then it may undergo secondary dissociation to form formaldehyde, H2CO. Either the primary or the secondary product may scatter directly into the gas phase before thermal equilibrium with the surface is reached, or they may become trapped on the surface and desorb in thermal equilibrium with the surface. Direct, single-collision scattering events that produce a C-C bond-breaking product are described with a kinematic picture that allows the determination of the effective surface mass encountered by an incident O atom, the atom-surface collision energy in the center-of-mass frame, and the fraction of the center-of-mass collision energy that goes into translation of the scattered gaseous product and the recoiling surface fragment. The dynamical behavior of the C-C bond-breaking reaction is compared with that of the H-atom abstraction reaction, which was the subject of an earlier study. Another reaction, H-atom abstraction by O2 (which is present in the hyperthermal beam), has also been observed, and the dynamics of this reaction are compared with the inelastic scattering dynamics of O2 and the dynamics of H-atom abstraction by O. The dynamics involving direct inelastic and reactive scattering of O2 are also described in terms of a kinematic picture where the incident O2 molecule is viewed as interacting with a local region of the surface.

The Effect of Temperature on the Breakdown Stress in Saturated Hydrocarbon Liquids

The Effect of Temperature on the Breakdown Stress in Saturated Hydrocarbon Liquids

Radiative and Nonradiative Deactivation of the 1 Δ g State of Molecular Oxygen in Solutions of Saturated Hydrocarbons

The luminescence of singlet molecular oxygen (1Δg or 1O2) caused by the 1Δg → 3Σg− transition in liquid saturated hydrocarbons from n-hexane to n-undecane is investigated. A model of quenching of the 1Δg state of the oxygen molecule by the CH oscillations of the molecules of solvents is proposed, in which the rate constant of the nonradiative deactivation (knr) depends strongly on the average distance between the 1O2 and CH groups of the solvent. This experimental dependence can adequately be described by an exponential function with the distance parameter R0 = 0.15 A, which indicates that the acceleration of quenching with the solvent density is a result of larger overlapping of the electron orbitals of oxygen and the CH groups. The detected increase in knr with temperature can also be explained qualitatively well within the framework of the model suggested. It is shown that the radiative rate constant (kr of the 1Δg → 3Σg− transition does not depend on the distance between the 1O2 and CH groups and its change in a number of hydrocarbons is related to macroscopic parameters, in particular, the polarizability of the solvent.

Comparative dynamics of Cl(2P) and O(3P) interactions with a hydrocarbon surface

The dynamics of the interactions of atomic chlorine with the surface of a saturated hydrocarbon liquid, squalane, were investigated and compared to the results of an earlier study on analogous oxygen-atom interactions. Beams of continuous supersonic chlorine atoms were directed onto a squalane surface, and the volatile products, Cl and HCl, were observed by mass spectrometry as a function of incident angle, final angle, and incident Cl-atom energy. Both the Cl and HCl time-of-flight (from the surface to the detector) distributions revealed thermal and hyperthermal interaction channels, in analogy to the dynamical behavior of the O and OH signals observed in the previous study. The thermal HCl product may arise from two mechanisms: (i) desorption of trapped HCl product and (ii) reaction of trapped Cl atoms to form thermal HCl, which subsequently desorbs. In contrast, the reaction of O atoms with squalane led to a thermal OH signal, which could only come from desorption of trapped OH. The hyperthermal HCl signal is the result of an Eley–Rideal direct-abstraction mechanism. An analogous reaction gave rise to hyperthermal OH products in O-atom reactions with squalane. The HCl and OH hyperthermal products were scattered preferentially in the specular direction in the laboratory frame. However, a kinematic analysis showed a propensity for scattering sideways or even backwards (with respect to the direction of the incident atomic beam) in the center-of-mass (c.m.) frame. The kinematic analysis also allowed the determination of the effective mass of the surface collision partner, the c.m. collision energy, and the final c.m. translational energy. Similar c.m. scattering dynamics have been observed in gas-phase reactions of O and Cl atoms with saturated hydrocarbons.

Liquid-Saturated Hydrocarbons Resulting from Pyrolysis of the Marine Coccolithophores Emiliania huxleyi and Gephyrocapsa oceanica.

: Two nanoplanktonic marine coccolithophores, Emiliania huxleyi and Gephyrocapsa oceanica, were grown at 23 degrees C with a 16-hour light and 8-hour darkness regimen. The cells were dried at room temperature and then subjected to pyrolysis at 100 degrees to 500 degrees C under anoxygenic conditions to produce hydrocarbons. Temperature-dependent profiles of the liquid-saturated hydrocarbons (saturates) produced during pyrolysis were very similar for the two strains, although the total amount was higher in E. huxleyi than in G. oceanica. The amount of saturates produced was only 0.05% to 0.15% below 200 degrees C, but about 2.1% to 2.8% at 300 degrees C. Their major components were normal alkanes in a series ranging from nC(11) to nC(35) with the predominant peak at nC(15). At 400 degrees and 500 degrees C most of saturates transformed into gaseous compounds. The major saturates identified in all pyrolysates were normal C(31) monounsaturated and diunsaturated alkenes, a series of normal alkanes, phytenes, C(28) sterenes, and steranes. Profiles of saturates in gas chromatography-mass spectroscopy varied with increasing pyrolysis temperature and also differed between E. huxleyi and G. oceanica. The two coccolithophores are useful candidates for the production of renewable liquid fuel through pyrolysis-especially E. huxleyi, which has higher production. The results also provide information for further studies on the characterization, source, and paleogeographic distribution of marine sediment.

Polymer swelling: 22. Molecular structure–affinity correlation studies that involve poly(styrene-co-divinylbenzene) exposed to saturated hydrocarbons

The adsorption parameters (α) for members of four classes of saturated hydrocarbons were compared with those observed for the corresponding ethers. The saturated hydrocarbon liquids exhibit a measurable affinity for polystyrene, as indicated by the linear relationships logαf=logαi−Ds(Nf−Ni), each characteristic of the homologous series being considered. These values increase from the linear series H(CH2)nH (αi=0.10±0.02; Ds=0.00±0.02) to those having the greatest affinity, members of the cyclic series (CH2)n, where αi=0.863 and Ds=0.0875. Even the latter, however, are considerably below the values for the corresponding cyclic ethers (CH2)nO (αi=3.31; Ds=0.0888), demonstrating the superiority of an oxygen atom and a methylene unit in affinity for the polymer's phenyl group.

Effects of chain length on prebreakdown phenomena in straight‐chain saturated hydrocarbon liquids

Prebreakdown light emission, currents, and streamers in straight-chain saturated hydrocarbon liquids, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane, are investigated under nonuniform field conditions. The light inception voltage and the breakdown voltage increase with the chain length and the liquid's density. For a negative point, the breakdown voltage is much higher than the light inception voltage in all liquids but the difference decreases with the chain length. This voltage difference is not observed for a positive point except in n-pentane and n-hexane. The difference between the negative and positive breakdown voltages decreases with the chain length. Regarding the polarity effect, the negative breakdown voltage is much higher than the positive one in n-pentane, but there is no difference in n-decane. A negative density change streamer has a bushlike structure and propagates in stepped manner at an average speed between 70 and 160 m/s, while for a positive one, the structure is treelike having an average speed of a few kilometers per second. Only in n-pentane and in n-hexane, a slow positive bushlike streamer is observed whose average velocity is about 200 m/s, slightly faster than the negative bushlike one. © 1998 Scripta Technica. Electr Eng Jpn, 122(4): 8–16, 1998

Effects of chain length on prebreakdown phenomena in straight-chain saturated hydrocarbon liquids

Prebreakdown light emission, currents, and streamers in straight-chain saturated hydrocarbon liquids, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane, are investigated under nonuniform field conditions. The light inception voltage and the breakdown voltage increase with the chain length and the liquid's density. For a negative point, the breakdown voltage is much higher than the light inception voltage in all liquids but the difference decreases with the chain length. This voltage difference is not observed for a positive point except in n-pentane and n-hexane. The difference between the negative and positive breakdown voltages decreases with the chain length. Regarding the polarity effect, the negative breakdown voltage is much higher than the positive one in n-pentane, but there is no difference in n-decane. A negative density change streamer has a bushlike structure and propagates in stepped manner at an average speed between 70 and 160 m/s, while for a positive one, the structure is treelike having an average speed of a few kilometers per second. Only in n-pentane and in n-hexane, a slow positive bushlike streamer is observed whose average velocity is about 200 m/s, slightly faster than the negative bushlike one. © 1998 Scripta Technica. Electr Eng Jpn, 122(4): 8–16, 1998

Low Concentration Anomalies in the Electronic Energy Transfer Behavior of Saturated Hydrocarbon Liquids

Low Concentration Anomalies in the Electronic Energy Transfer Behavior of Saturated Hydrocarbon Liquids

Computer Simulation of the Ion Escape from High-Energy Electron Tracks in Nonpolar Liquids

The number of ions escaping from recombination in high-energy electron tracks in saturated hydrocarbon liquids is calculated and compared with experimental results from the literature. The initial ...

直鎖状飽和炭化水素液体の破壊前駆現象に及ぼす直鎖長の影響

直鎖状飽和炭化水素液体の破壊前駆現象に及ぼす直鎖長の影響

Triboemission of Electrons and Ions During Wear of Solids Under Boundary Lubrication with Saturated Hydrocarbon Liquids

The triboemission behavior of charged particles was measured under boundary lubrication of saturated hydrocarbon liquids during scratching of various solids by a diamond stylus. The solids tested were the metals Cu, Al and Fe, ceramics Si, ZrO2, Si3N4, Al2O3, soda lime glass and mica, polymers of 6, 6-nylon and PTFE. Saturated hydrocarbons of n-hexane, n-undecane and n-hexadecane were used as lubricating oils. Triboemission occurred in bursts and ceased abruptly as scratching was started and stopped. The emission intensity of the charged particles depended closely on the kinds of solids, especially on their insulating properties, with an increase of emission intensity in the order of conductor < semiconductor < insulator. The emission intensity decreased as the hardness of the solids increased. These emission characteristics under the boundary lubrication condition are principally the same as in dry friction under ambient conditions.

Triboemission of charged particles from various solids under boundary lubrication conditions

Triboemission under boundary lubrication conditions from various solids has successfully been measured. The dependence of triboemission intensity on time, normal force and sliding velocity was studied for negatively and positively charged particles emitted while scratching various metals, ceramics and polymers with a diamond stylus under boundary lubrication with saturated hydrocarbon liquids. Negatively charged particles were detected more intensely than positively charged particles for all solids tested except PTFE. The emission intensity increased with normal force and sliding velocity, and was high for insulating solids such as ceramics and polymers, while low for metals. The emission intensities under boundary lubrication were lower than under dry friction in room air, although the friction coefficients were comparable. The results are discussed in relation to the emission characteristics under dry sliding in room air.

ChemInform Abstract: The Fluorescence Action Spectra of Some Saturated Hydrocarbon Liquids for Excitation Energies Above and Below Their Ionization Thresholds.

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The fluorescence action spectra of some saturated hydrocarbon liquids for excitation energies above and below their ionization thresholds

Fluorescence action spectra have been obtained for the neat liquids, cis-decalin, trans-decalin, bicyclohexyl, cyclohexane, methylcyclohexane, isobutylcyclohexane, 2,3,4-trimethylpentane, 2,3-dimethylbutane, 3-methylhexane, 3-methylpentane, n-decane, n-dodecane, and n-pentadecane at excitation energies, ε, ranging from their absorption onsets (at ca. 7 eV) to 10.3 eV. For all compounds, with the exception of cis-decalin, the fluorescence quantum yield is observed to monotonically decline with increasing ε, reaching a minimum value at an energy, εm (a few tenths of an eV above the liquid phase ionization threshold, εl) followed by a slow increase. In the case of cis-decalin, the fluorescence quantum yield remains constant over the entire range of excitation energies studied, permitting its use as a quantum counter replacing the standard sodium salicylate, at least over a spectral range from 185 to 120 nm. The recovery of the fluorescence quantum yield for ε≳εm is attributed to an increasing probability for electron ejection followed by e−+RH+ geminate recombination, to produce an excited state of RH with energy less than εl. From a simple analysis of the action spectrum, a lower bound estimate of the electron ejection probability, φ±, is obtained as a function of ε. In the case of cyclohexane, where φ± has been obtained by other techniques at ε≂10 eV, the lower bound estimate agrees with the experimental value. From this agreement, arguments are presented to make plausible the conjecture that in all these liquids, the initially produced e−+RH+ geminate ion pair first rapidly internally converts to an ion-pair state ca. 1.6 eV below εl, which then collapses to generate the fluorescent state of RH with an energy close to its absorption threshold value (ca. 7 eV).

Confined geometry effects on reorientational dynamics of molecular liquids in porous silica glasses

This work investigates the relative role of the pure geometrical confinement and the strength of the surface effect on the dynamics of liquids in porous silica glasses prepared by the sol-gel process. The deuteron NMR spin-lattice relaxation times T1 of several molecular liquids in porous silica glasses are reported as function of pore size in the range from 18 to 143 Å over the temperature range from 260 to 310 K. Molecular liquids studied include strongly interacting polar liquids such as pyridine-d5, aniline-d5, and nitrobenzene-d5, whereas the saturated cyclic hydrocarbon liquids of cyclohexane-d12 and cis-decalin-d18 represent the weakly interacting liquids. In a first approximation, toluene-d1 and dioxane-d18 are chosen as examples of liquids with intermediate interactions with the silica surface. The experimental relaxation data are analyzed by using the two-state, fast-exchange model which is found to be valid for the strongly interacting liquids and liquids with intermediate interactions. In terms of this model, the viscosity of the surface layer for pyridine-d5 is about 30 times higher than that for bulk liquid pyridine. The importance of the two-dimensional approach to describe motional dynamics of liquids confined to pores smaller than 30 Å is illustrated in the case of weakly interacting liquid of cyclohexane-d12. Additional information on the relative role of surface interactions and the pure topological effects on the dynamics of liquids in confined geometries was obtained by using surface-modified glasses in which the surface hydroxyl groups were replaced by OSi(CH3)2OC2H5 groups. Indeed, the effects of surface modifications on the 2H T−11 are most pronounced for strongly interacting liquids whereas they are absent for cyclohexane. In agreement with the concept of two-dimensional behavior of liquids in small pores, one finds that the low-frequency relaxation times, namely, the spin–spin relaxation time T2, and the spin-lattice relaxation time in the rotating coordinate frame, T1ρ, remain unchanged by surface modification. In fact, this is a consequence of logarithmic enhancement of the spectral density at low frequencies so that the effect of pure geometrical confinement on the T−12 and T−11ρ relaxation rates is much larger than any relaxation rate changes arising from surface modification. Several selected NMR T1 experiments on pyridine-d5 confined to anopore and zeolites are also presented.

Muonated cyclohexadienyl radicals observed by level crossing resonance in dilute solutions of benzene in hexane subjected to muon-irradiation

Benzene is used here as a scavenger of muonium to produce the muonated cyclohexadienyl radical in dilute solutions in n-hexane. The radical was identified by level crossing resonance spectroscopy (LCR) by observing the proton resonance of the —CHMu group occuring at 2.059T. Its yield is found to equal the sum of the muonium atom yield and the “missing” muon yield in hexane (total 35% of the incident muons). Consequently, the complete dispersement of muons in different chemical associations is now accounted for in a saturated hydrocarbon liquid, and is seen to be similar to that in water.