Influence of Operating Condition and Geometry on the Oil Film Thickness in Aeroengine Bearing Chambers

2004 ◽  
Vol 128 (1) ◽  
pp. 103-110 ◽  
Author(s):  
P. Gorse ◽  
S. Busam ◽  
K. Dullenkopf
Keyword(s):  
Film Thickness ◽  
Film Flow ◽  
Jet Engines ◽  
Gravity Forces ◽  
Wide Range ◽  
Secondary Air ◽  
Oil Films ◽  
Analytical Approaches ◽  
Complex Film

Increasing the efficiency of modern jet engines does not only imply to the mainstream but also to the secondary air and oil system. Within the oil system the bearing chamber is one of the most challenging components. Oil films on the chamber walls are generated from oil droplets, ligaments, or film fragments, which emerge from bearings, seal plates and shafts, and enter the bearing chamber with an angular momentum. Furthermore, shear forces at its surface, gravity forces, and the design of scavenge and vent ports strongly impact the behavior of the liquid film. The present paper focuses on the experimental determination of the film thickness in various geometries of bearing chambers for a wide range of engine relevant conditions. Therefore, each configuration was equipped with five capacitive probes positioned at different circumferential locations. Two analytical approaches are used for a comprehensive discussion of the complex film flow.

Influence of Operating Condition and Geometry on the Oil Film Thickness in Aero-Engine Bearing Chambers

2004 ◽  
Author(s):  
P. Gorse ◽  
S. Busam ◽  
K. Dullenkopf
Keyword(s):  
Film Thickness ◽  
Jet Engines ◽  
Gravity Forces ◽  
Wide Range ◽  
Secondary Air ◽  
Oil Films ◽  
Analytical Approaches ◽  
Complex Film ◽  
Engine Bearing

Increasing the efficiency of modern jet engines do not only imply to the mainstream but also to the secondary air and oil system. Within the oil system the bearing chamber is one of the most challenging component. Oil films on the chamber walls are generated from oil droplets, ligaments, or film fragments, which emerge from bearings, seal plates and shafts, and enter the bearing chamber with an angular momentum. Furthermore, shear forces at its surface, gravity forces, and the design of scavenge and vent ports strongly impact the behavior of the liquid film. The present paper focuses on the experimental determination of the film thickness is various geometries of bearing chambers for a wide range of engine relevant conditions. Therefore, each configuration was equipped with five capacitive probes positioned at different circumferential locations. Two analytical approaches are used for a comprehensive discussion of the complex film flow.

The determination of the pressure—viscosity coefficient of a lubricant through an accurate film thickness formula and accurate film thickness measurements

2009 ◽  
Vol 223 (8) ◽  
pp. 1143-1163 ◽  
Author(s):  
H van Leeuwen
Keyword(s):  
Film Thickness ◽  
Viscosity Coefficient ◽  
Test Fluid ◽  
Limited Data ◽  
Ehd Lubrication ◽  
Spacer Layer ◽  
Wide Range ◽  
Approximation Formulas ◽  
Thickness Measurements

The pressure—viscosity coefficient is an indispensable property in the elastohydrodynamic (EHD) lubrication of hard contacts, but often not known. A guess will easily lead to enormous errors in the film thickness. This article describes a method to deduct this coefficient by adapting the value of the pressure—viscosity coefficient until the differences between accurate film thickness approxi-mation values and accurate film thickness measurements over a wide range of values are at a minimum. Eleven film thickness approximation formulas are compared in describing the film thickness of a test fluid with known value of the pressure—viscosity coefficient. The measurement method is based on spacer layer interferometry. It is concluded that for circular contacts the newer more versatile expressions are not better than some older approximations, which are limited to a smaller region of conditions, and that the older fits are as least as appropriate to find the pressure—viscosity coefficient of fluids, in spite of the limited data where they have been based on.

Optimized External IR Reflection Spectroscopy for Quantitative Determination of Borophosphosilicate Glass Parameters

1997 ◽  
Vol 51 (2) ◽  
pp. 259-264 ◽  
Author(s):  
Lizhong Zhang ◽  
James E. Franke ◽  
Thomas M. Niemczyk ◽  
David M. Haaland
Keyword(s):  
Film Thickness ◽  
Quantitative Determination ◽  
Least Squares ◽  
Partial Least Squares ◽  
Reflection Spectroscopy ◽  
Ir Radiation ◽  
Ir Reflection ◽  
Wide Range ◽  
Borophosphosilicate Glass

Infrared (IR) external reflection spectroscopy has been optimized for the quantitative determination of composition and film thickness of borophosphosilicate glass (BPSG) deposited on silicon wafer substrates. The precision of the partial least-squares calibrations for boron and phosphorus contents and thin-film thickness were measured as the cross-validated standard error of prediction statistic. The results showed that BPSG IR reflection spectra collected over a wide range of incident IR radiation angles (15°, 25°, 45°, and 60°) can be used for the simultaneous quantification of these three BPSG parameters. When high angles of incidence were employed, the measurement was found to be more sensitive to small errors in the angle of incidence. The polarization state of the incident IR radiation did not noticeably affect the prediction of the three calibrated BPSG parameters. The results achieved in this study provide guidelines for at-line process monitoring and quality control of BPSG thin films used in the fabrication of microelectronic devices. Index Headings: IR reflection; Multivariate calibration; Partial least-squares

scholarly journals Analysis of 15N-NO3− Via Anoxic Slurries Coupled to MIMS Analysis: An Application to Estimate Nitrification by Burrowing Macrofauna

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2310
Author(s):  
Carpintero Moraes ◽  
Arroyave Gòmez ◽  
Vincenzi ◽  
Castaldelli ◽  
Fano ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Stable Isotope ◽  
Microbial Reduction ◽  
Ecological Studies ◽  
Anoxic Sediment ◽  
Ecological Processes ◽  
Membrane Inlet Mass Spectrometry ◽  
Wide Range ◽  
Analytical Approaches

The increasing use of the stable isotope 15N-NO3− for the quantification of ecological processes requires analytical approaches able to distinguish between labelled and unlabeled N forms. We present a method coupling anoxic sediment slurries and membrane inlet mass spectrometry to quantify dissolved 15N-NO3− and 14N-NO3−. The approach is based on the microbial reduction of 14N-NO3− and 15N-NO3− mixed pool, the determination of the produced 29N2 and 30N2, and the calculation of the original 15N-NO3− and 14N-NO3− concentrations. The reduction is carried out in 12 mL exetainers containing 2 mL of sediment and 10 mL of water, under anoxia. To validate this approach, we prepared multiple standard solutions containing 15N-NO3− alone or in combinations with 14N-NO3−, with final concentrations varying from 0.5 to 3000 µM. We recovered nearly 90% of the initial 14N-NO3− or 15N-NO3−, over a wide range of concentrations and isotope ratios in the standards. We applied this method to a 15N-NO3− dilution experiment targeting the measurement of nitrification in sediments with and without the burrower Sparganophilus tamesis. The oligochaete did not stimulate nitrification, likely due to limited ventilation and unfavorable conditions for nitrifiers growth. The proposed method is reliable, fast, and could be applied to multiple ecological studies.

Leak Rates of Gasses Through Packing Seals With Different Analytical Approaches

2017 ◽  
Author(s):  
Ali Salah Omar Aweimer ◽  
Abdel-Hakim Bouzid ◽  
Mehdi Kazeminia
Keyword(s):  
Flow Regime ◽  
Stokes Equations ◽  
Soft Materials ◽  
Flow Models ◽  
Micro Channels ◽  
Wide Range ◽  
Packing Rings ◽  
Analytical Approaches

Predicting leakage in packed stuffing boxes is a major engineering challenge to designers and end users. Due to the different working conditions and material products, the determination of the flow regime present in packing rings is not a straightforward task to predict. This paper presents a study on the ability of micro channel flow models to predict leak rates through packing rings made of soft materials such as graphite. A methodology based on the experimental characterization of the porosity parameters is developed to predict leak rates at different compression stress levels. Three different models are compared to predicate the leakage, where the diffusive and second order flow models are derived from Naiver-Stokes equations and incorporate the boundary conditions of an intermediate flow regime to cover the wide range of leak rate levels. The lattice model is based on porous media of packing rings as packing bed (Dp). The flow porosity parameters (Rc,Dp) of the micro channels assumed to simulate the leak paths present in the packing are obtained experimentally. The predicted leak rates from different gasses (He, N2, Ar) are compared to those measured experimentally, in which the set of packing rings is mainly subjected to different gland stresses and pressures.

DINAMIKA POLITIK PERSETUJUAN BERSAMA TENTANG PENETAPAN DESA ADAT DI KABUPATEN ROKAN HULU TAHUN 2014

2017 ◽  
Vol 15 (1) ◽  
pp. 21
Author(s):  
Haryo Suganda ◽  
Raja Muhammad Amin
Keyword(s):  
Regulatory Region ◽  
Field Research ◽  
Analysis Techniques ◽  
Political Dynamics ◽  
Political Interests ◽  
Wide Range ◽  
Information Method ◽  
Qualitative Descriptive ◽  
The Village

This study is motivated the identification of policies issued by the regional Governmentof Rokan Hulu in the form of Regulatory region number 1 by 2015 on the determination of thevillage and Indigenous Village. Political dynamics based on various interests against themanufacture of, and decision-making in the process of formation of the corresponding localregulations determination of Indigenous Villages in the Rokan Hulu is impacted to a verysignificantamount of changes from the initial draft of the number i.e. 21 (twenty one) the villagebecame Customary 89 (eighty-nine) the Indigenous Villages who have passed. Type of thisresearch is a qualitative descriptive data analysis techniques. The research aims to describe theState of the real situation in a systematic and accurate fact analysis unit or related research, aswell as observations of the field based on the data (information). Method of data collectionwas done with interviews, documentation, and observations through fieldwork (field research).The results of the research on the process of discussion of the draft local regulations andmutual agreement about Designation of Indigenous Villages in the Rokan Hulu is, showed thatthe political dynamics that occur due to the presence of various political interests, rejectionorally by Villagers who were judged to have met the requirements of Draft Regulations to beformulated and the area for the set to be Indigenous Villages, and also there is a desire fromsome villages in the yet to Draft local regulations in order to set the Indigenous village , there isa wide range of interests of these aspects influenced the agreement to assign the entire localVillage which is in the Rokan Hulu become Indigenous village, and the village of Transmigrationinto administrative Villages where the initiator of the changes in the number of IndigenousVillages in the Rokan Hulu it is the desire of the local Government of its own.

Advances in the Chromatographic Separation and Determination of Bioactive Compounds for Assessing the Nutrient Profile of Nuts

2020 ◽  
Vol 16 ◽  
Author(s):  
Natasa P. Kalogiouri ◽  
Natalia Manousi ◽  
Erwin Rosenberg ◽  
George A. Zachariadis ◽  
Victoria F. Samanidou
Keyword(s):  
Fatty Acids ◽  
Phenolic Compounds ◽  
Bioactive Compounds ◽  
High Performance ◽  
Unsaturated Fatty Acids ◽  
Nutritional Deficiencies ◽  
Analytical Technique ◽  
High Volatility ◽  
Analytical Approaches

Background:: Nuts have been incorporated into guidelines for healthy eating since they contain considerable amounts of antioxidants and their effects are related to health benefits since they contribute to the prevention of nutritional deficiencies. The micronutrient characterization is based mainly on the determination of phenolics which is the most abundant class of bioactive compounds in nuts. Terpenes constitute another class of bioactive compounds that are present in nuts and show high volatility. The analysis of phenolic compounds and terpenes are very demanding tasks that require optimization of the chromatographic conditions to improve the separation of the components. Moreover, nuts are rich in unsaturated fatty acids and they are therefore considered as cardioprotective. Gas chromatography is the predominant instrumental analytical technique for the determination of derivatized fatty acids and terpenes in food matrices, while high performance liquid chromatography is currently the most popular technique for the determination of phenolic compounds Objective:: This review summarizes all the recent advances in the optimization of the chromatographic conditions for the determination of phenolic compounds, fatty acids and terpenes in nuts Conclusion:: The state-of-the art in the technology available is critically discussed, exploring new analytical approaches to reduce the time of analysis and improve the performance of the chromatographic systems in terms of precision, reproducibility, limits of detection and quantification and overall quality of the results

scholarly journals Characterization and Quantification of Selenoprotein P: Challenges to Mass Spectrometry

2021 ◽  
Vol 22 (12) ◽  
pp. 6283
Author(s):  
Jérémy Lamarche ◽  
Luisa Ronga ◽  
Joanna Szpunar ◽  
Ryszard Lobinski
Keyword(s):  
Mass Spectrometry ◽  
State Of The Art ◽  
Animal Health ◽  
Primary Standard ◽  
Selenoprotein P ◽  
Primary Standards ◽  
Analytical Approaches ◽  
Careful Investigation ◽  
Accurate Quantification

Selenoprotein P (SELENOP) is an emerging marker of the nutritional status of selenium and of various diseases, however, its chemical characteristics still need to be investigated and methods for its accurate quantitation improved. SELENOP is unique among selenoproteins, as it contains multiple genetically encoded SeCys residues, whereas all the other characterized selenoproteins contain just one. SELENOP occurs in the form of multiple isoforms, truncated species and post-translationally modified variants which are relatively poorly characterized. The accurate quantification of SELENOP is contingent on the availability of specific primary standards and reference methods. Before recombinant SELENOP becomes available to be used as a primary standard, careful investigation of the characteristics of the SELENOP measured by electrospray MS and strict control of the recoveries at the various steps of the analytical procedures are strongly recommended. This review critically discusses the state-of-the-art of analytical approaches to the characterization and quantification of SELENOP. While immunoassays remain the standard for the determination of human and animal health status, because of their speed and simplicity, mass spectrometry techniques offer many attractive and complementary features that are highlighted and critically evaluated.

scholarly journals Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

2021 ◽  
Vol 18 (4) ◽  
pp. 1768
Author(s):  
Hernâni Marques ◽  
Pedro Cruz-Vicente ◽  
Tiago Rosado ◽  
Mário Barroso ◽  
Luís A. Passarinha ◽  
...  
Keyword(s):  
Tobacco Smoke ◽  
Solid Phase ◽  
Smoke Exposure ◽  
Tobacco Smoke Exposure ◽  
World Health ◽  
Second Hand Smoke ◽  
Tobacco Exposure ◽  
Wide Range ◽  
Recent Developments

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid–liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

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