Contaminants in Used Oils and Their Problems

2006 ◽  
Vol 220 (5) ◽  
pp. 471-478 ◽  
Author(s):  
A Sasaki
Keyword(s):  
Membrane Filter ◽  
The Other ◽  
Oil Contamination ◽  
Gravimetric Analysis ◽  
Contamination Control ◽  
Lubricating Oils ◽  
Particle Count ◽  
Filter Disc ◽  
Particulate Contaminants

Contaminants in hydraulic and lubricating oils are harmful to lubrication. Therefore, contamination control of hydraulic and lubricating oils has been implemented in many factories and oil cleanliness standards of hydraulic and lubricating oils have been established as criteria for oil contamination control. There are two types of oil cleanliness standards: one is based on particle count and the other on gravimetric analysis. NAS 1638, ISO 4406, SAE AS4059, and JISB9930 belong to the former and ASTM D4898 and JISB9931 to the latter. The par tide count defines oil cleanliness by counting the number of particulate contaminants in the certain size ranges, and the gravimetric analysis shows the weight of contaminants remaining, on a membrane filter disc after a certain quantity of oil was filtered under vacuum, the oil was washed out, and the membrane filter disc was completely dried. Recently, there is a ten dency that particle count dominates the technology to judge oil cleanliness. Of course, it is important to quantify the number of particulate contaminants in oils. However, all particles are not contaminants, as particles like graphite and MoS2, which are countable by particle count, are good additives for lubricants. Therefore, it is very important for us not only to judge oil cleanliness by the particle count but also to know without prejudice what they are. This article discusses some methods to separate contaminants, what contaminants are, and how much they are.

scholarly journals The Effect of the Multi-doping Strategy on Stabilization of the Cubic δ-phase in the Bi2O3-based Solid Electrolyte Systems in Terms of the SOFC Applications

2021 ◽  
Author(s):  
Murat BALCI ◽  
Mehmet Arı ◽  
Yasin Polat
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Electrical Conductivity ◽  
The Other ◽  
Gravimetric Analysis ◽  
Sudden Increase ◽  
Dopant Content ◽  
Α Phase ◽  
Δ Phase ◽  
Dta Curve

Abstract In this study, the effects of multi-doping strategy on phase stabilization and electrical conductivity for the doped Bi 2 O 3 system were investigated. All solid mixtures were created by solid state reactions according to a certain stoichiometric ratio in atmospheric conditions. The structural, electrical, thermal and surface characterizations of the created samples were performed by x-ray diffraction method (XRD), four point-probe technique (4-PPT), differential thermal analysis/thermo gravimetric analysis (DTA/TGA) and scanning electron microscope (SEM), respectively. From XRD results, it was seen that the fcc δ-phase could be stabilized by using only 1:1:1:2 or 2:2:2:1 dopant content ratio (in here, “1:” is corresponds to” 5%” mole). The other compounds prepared out of this ratios were mixed phase because of the containing both α-phase peaks and δ-phase peaks on their XRD pattern. When the all samples were compared in terms of electrical conductivity at 750 °C, it was observed that the fcc δ-phase stabilized samples exhibited higher conductivity than that of other compounds as expected. The highest electrical conductivity was for the sample, dopant content ratios of which are 1: 1: 1: 2, with 0.014 S.cm -1 at 750 °C and also it had the lowest activation energy (0.51 eV) among all samples. On the other hand, according to the thermal analysis results, it was concluded that phase transition occurred only on the DTA curve of the sample given with dopant content ratios 1:1:1:1 due to presence of endothermic peak on its DTA curve at 729°C during the heating process. Also, for this sample, it was clearly predicted from the electrical conductivity graphs depending on temperature that the phase transition occurred at just that temperature (729 °C) due to the sudden increase in conductivity by indicating phase transition from the α-phase to the cubic δ-phase. The SEM analysis pointed out that grain size decreased as total dopant ratio increased and also the grain boundary changed sharply with the increase in the total dopant ratio.

A comparison of Centrifugal and Membrane-based Apheresis Formats

1984 ◽  
Vol 7 (1) ◽  
pp. 35-38 ◽  
Author(s):  
H.J. Gurland ◽  
M.J. Lysaght ◽  
W. Samtleben ◽  
B. Schmidt
Keyword(s):  
Free Product ◽  
Whole Blood ◽  
Plasma Proteins ◽  
Membrane Filter ◽  
The Other ◽  
Centrifugal Method ◽  
Protein Clearance ◽  
Continuous Centrifugation ◽  
Membrane Methods ◽  
Physical Principles

Membrane and centrifugal apheresis operate on different physical principles but are both capable of efficiently fractionating plasma proteins from whole blood. For therapeutic purposes, both formats yield about the same protein clearance per liter of solute exchanged and neither is significantly more rapid than the other. Only continuous centrifugation can be used to pherese cellular elements and only membrane filter can be deployed in ‘spontaneous’ circuits. Hardware for continuous centrifugation is more expensive and disposables less expensive than for the membrane methods; the ‘crossover’ occurs at 200 treatments. To date, only the centrifugal method is employed for donor apheresis; this may change in the future as membranes can yield a truly platelet-free product and appear to offer a much more rapid collection cycle.

scholarly journals Evaluation of methods for water and non-volatile LNAPL content measurement in porous media

2019 ◽  
Vol 14 (No. 1) ◽  
pp. 47-56
Author(s):  
Ayele Teressa Chala ◽  
Svatopluk Matula ◽  
Kamila Báťková ◽  
František Doležal
Keyword(s):  
Porous Media ◽  
Soil Moisture ◽  
Water Content ◽  
High Standard ◽  
The Other ◽  
Gravimetric Analysis ◽  
Analysis Method ◽  
Soil Moisture Sensors ◽  
Phase Liquid ◽  
Proper Estimation

Proper characterization of contaminants in subsurface helps to clean up effectively the contaminated sites. In this study, different methods were used to quantify non-volatile light non-aqueous phase liquid (LNAPL) and water from sample columns subjected to different water to LNAPL ratios. The objective of the study was to evaluate methods for porous media water and LNAPL contents analysis. The liquids were sampled from the sample columns using activated carbon pellets (ACP). Sample columns water content was also measured using soil moisture sensors. Dielectric mixing model (DMM) was evaluated for the estimation of LNAPL content after water and LNAPL contents of the sample columns were determined through gravimetric analysis method. The result shows that it was possible to sample both water and LNAPL using ACP proportionally but with high standard deviations. It also shows that more liquid was sampled from sample columns subjected to only one liquid compared to sample columns subjected to two liquids. On the other hand, analysis of water and LNAPL using gravimetric analysis method gave the best result although the presence of LNAPL resulted in underestimation of water content at higher LNAPL contents. Meanwhile, the presence of LNAPL modified the bulk relative permittivity (ε<sub>a</sub>) of the sample columns and resulted in overestimation of water contents measured using soil moisture sensors at higher LNAPL content. The modification of ε<sub>a</sub> was used for the estimation of LNAPL using DMM. The evaluation of the model with known water and LNAPL contents and in estimating the LNAPL content of the other sample columns shows that the model could be used for the proper estimation of LNAPL in porous media.  

scholarly journals Effect of recombinant erythropoietin in interaction with stromal factors on cord blood hematopoiesis

Blood ◽  
1996 ◽  
Vol 87 (8) ◽  
pp. 3212-3217 ◽  
Author(s):  
T Abe ◽  
Y Takaue ◽  
Y Kawano ◽  
Y Kuroda
Keyword(s):  
Cord Blood ◽  
Progenitor Cells ◽  
Mononuclear Cells ◽  
Membrane Filter ◽  
Culture Conditions ◽  
The Other ◽  
Recombinant Erythropoietin ◽  
Other Hand ◽  
Cd34 Cells

To investigate the effect of recombinant erythropoietin (Epo) on primitive human hematopoietic progenitor cells, we cultured cord blood mononuclear cells (CBMNC) and CB CD34+ cells in a Dexter-type long-term culture system (LTC), to which various concentrations of Epo were added at day 0 or 7, with or without direct contact with irradiated allogeneic human marrow stromal layers. In regular stroma-contact cultures, when CBMNC were inoculated, the addition of Epo at 1 to 10 U/mL induced a significant increase in LTC-initiating cells (LTC-IC), particularly in the myeloid component, compared with the control without Epo. Significantly more LTC-IC were generated by the delayed addition of Epo on day 7 than on day 0. On the other hand, when CD34+ cells were inoculated, physiologic concentrations of Epo (0.1 U/mL) induced a more than twofold increase in LTC-IC, which was attributed equally to both the myeloid and erythroid lineages, only when added on day 0. In stroma-noncontact cultures, which were created using a Transwell 0.4-micron microporous membrane filter, dose-dependent suppression of the myeloid component of LTC-IC was observed with a higher concentration of Epo (1 to 100 U/mL) when CBMNC was inoculated. On the other hand, without Epo, fourfold more LTC-IC was generated from CD34+ cells in stroma-noncontact than in stroma-contact cultures, which was then significantly augmented by the addition of Epo (0.1 or 10 U/mL) on day 0. This increase was due to both the myeloid and erythroid lineages. A higher concentration of Epo (100 U/mL) resulted in a decrease in LTC-IC, mainly in myeloid progeny, in all of the culture conditions. Hence, Epo may play an important physiologic role in the maintenance and proliferation of immature stem/progenitor cells, in close interaction with factors from marrow stromal cells.

A New Rubber Particle Count in Hevea Latex

1936 ◽  
Vol 9 (4) ◽  
pp. 644-647
Author(s):  
Earle E. Langeland
Keyword(s):  
Original Work ◽  
Rubber Particle ◽  
Fundamental Property ◽  
The Other ◽  
Rubber Content ◽  
Microscopic Method ◽  
Particle Count ◽  
Rubber Particles ◽  
The One

Abstract SO MUCH confusion has grown up in the literature concerning the number of rubber particles in Hevea latex that at the present time there exists a thousandfold error in the currently published reports (1, 3, 8) of the one original determination of this number. Harries (4), Hauser (5), and Noble (8), each reporting the original work of Henri (6), give a count of 50,000,000 particles per cubic centimeter of latex, Harries not specifying the concentration, while Hauser and Noble indicate it to have been 8.7 per cent solids. On the other hand, Dubosc and Luttringer (2), also reporting the work of Henri, record a count of 50,000,000 particles per cubic millimeter in latex of unspecified concentration. The original paper of Henri (6) reported that he had found an average of 50,000,000 particles per cubic millimeter of latex having a specific gravity of 0.973 and containing 8.7 grams of solids per 100 cc. Preliminary counts undertaken by the author with a view to developing a rapid microscopic method for the determination of the dry rubber content of latex indicated that the results of Henri were considerably low. Since the number of microscopically visible particles is a fundamental property of latex, it was felt that a redetermination of this number would be of value.

scholarly journals Field Evaluation of the Membrane Filter-Disc Immunoimmobilization Technique in the Detection of Salmonellae in Egg Products

1981 ◽  
Vol 60 (10) ◽  
pp. 2265-2269 ◽  
Author(s):  
R.N. LaROCHE ◽  
V. DESAI ◽  
BARBARA FRIEDMAN ◽  
B. SWAMINATHAN
Keyword(s):  
Membrane Filter ◽  
Field Evaluation ◽  
Filter Disc ◽  
Egg Products

Cavitation Phenomena in Pure-Sliding Grease EHL Films

2010 ◽  
Author(s):  
Takefumi Otsu ◽  
Yuichiro Nagata ◽  
Joichi Sugimura ◽  
Romeo Glovnea
Keyword(s):  
The Other ◽  
Complex Nature ◽  
Operating Parameters ◽  
Lubricating Grease ◽  
Lubricating Oils ◽  
Lubrication Regime ◽  
Ehd Lubrication ◽  
Machine Elements ◽  
Grease Composition

Grease lubricants are widely used in many machine elements which work in elastohydrodynamic (EHD) lubrication regime. They have advantages over lubricating oils, but are prone to starvation, especially when operating at large speeds. At the same time the complex nature of lubricating grease is little understood and only little knowledge about its chemistry and physics is accessible, which makes the prediction of grease film behavior difficult. In the present paper the relation between lubricating grease composition and operating parameters on one hand and the cavitation length on the other, was evaluated.

Modification in Surface Chemistry of the Polyetrafluoroethylene Through Chemical Graft Copolymerization for Potential Oil Contamination Control

2014 ◽  
Vol 32 (2) ◽  
pp. 158-163 ◽  
Author(s):  
Rishi Dewan ◽  
Neeraj Kumar ◽  
Bhawna Yadav ◽  
Vandana Yadav ◽  
Abhijit Biswas ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Graft Copolymerization ◽  
Oil Contamination ◽  
Contamination Control

scholarly journals Quantifying Crude Oil Contamination in Sand and Soil by EPR Spectroscopy

2021 ◽  
Author(s):  
Bulat Gizatullin ◽  
Eric Papmahl ◽  
Carlos Mattea ◽  
Siegfried Stapf
Keyword(s):  
Crude Oil ◽  
Epr Spectroscopy ◽  
Soil Analysis ◽  
The Other ◽  
Oil Contamination ◽  
Natural Environments ◽  
Oil Spillage ◽  
Stable Radicals ◽  
Iron Manganese ◽  
Metallic Species

AbstractCrude oil frequently contains stable radicals that allow detection by means of EPR spectroscopy. On the other hand, most sands and soils possess significant amounts of iron, manganese or other metallic species that often provide excessively broad EPR signatures combined with well-defined sharp features by quartz defects. In this study, we demonstrate the feasibility to identify oil contamination in natural environments that are subject to oil spillage during production on land, as well as beachside accumulation of marine oil spillage. Straightforward identification of oil is enabled by the radical contributions of asphaltenes, in particular by vanadyl multiplets that are absent from natural soils. This potentially allows for high-throughput soil analysis or the application of mobile EPR scanners.

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