15 research outputs found
Self-Excited Vibration of Statically Unloaded Pads in Tilting-Pad Journal Bearings
load characteristics are satisfactory if ^m«0.66ap, but these pads do not have tendencies to loose their stability
Short review of the CFD activities in Poland
Computational fluid dynamics is being developed at several universities and scientific centres in Poland. These centres are considered and a general description of CFD activities is provided. It should be emphasised that the centres mentioned are only the best known ones. The information provided has been prepared in co-operation with the responsible scientists and is authorised by them. Therefore the form of topics description is not uniform
CFD Analysis of a Simple Orifice-Type Feeding System for Aerostatic Bearings
A numerical analysis on the feeding system of externally pressurised gas bearings, for the correction of the theoretical mass flow rate formula by means of a discharge coefficient, is presented. A flat aerostatic pad with a simple orifice-type feeding system was chosen as case on study, the authors having previously carried out experimental tests on such a prototype. Using the commercial CFD code ANSYS Fluent, preliminary simulations were carried out on a pad's geometry using three different flow models. Having selected the flow model able to give the best prediction of the pad's behaviour in terms of pressure distribution along the air film, additional simulations were carried out on pads with two different diameters of the supply hole, varying the film thickness in a range from 9 to 14 lm. A comparison between numerical and experimental results is presented. In addition, the effect of the flow intake used to perform experimental tests and of the shape of the orifice's external edge on pressure distribution is analyse
Identification, Synthesis, and Characterization of Novel Sulfur-Containing Volatile Compounds from the In-Depth Analysis of Lisbon Lemon Peels (Citrus limon L. Burm. f. cv. Lisbon)
Lemons
(Citrus limon) are a desirable
citrus fruit grown and used globally in a wide range of applications.
The main constituents of this sour-tasting fruit have been well quantitated
and characterized. However, additional research is still necessary
to better understand the trace volatile compounds that may contribute
to the overall aroma of the fruit. In this study, Lisbon lemons (<i>C. limon</i> L. Burm. f. cv. Lisbon) were purchased from a grove
in California, USA, and extracted by liquid–liquid extraction.
Fractionation and multidimensional gas chromatography–mass
spectrometry were utilized to separate, focus, and enhance unidentified
compounds. In addition, these methods were employed to more accurately
assign flavor dilution factors by aroma extract dilution analysis.
Numerous compounds were identified for the first time in lemons, including
a series of branched aliphatic aldehydes and several novel sulfur-containing
structures. Rarely reported in citrus peels, sulfur compounds are
known to contribute significantly to the aroma profile of the fruit
and were found to be aroma-active in this particular study on lemons.
This paper discusses the identification, synthesis, and organoleptic
properties of these novel volatile sulfur compounds