Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fluid leakage in metallic seals   Metallic seals are crucial machine elements in many important applications,
e.g., in ultrahigh vacuum systems. Due to the high elastic modulus of metals,
and the surface roughness which exists on all solid surfaces, if no plastic
deformation would occur one expects in most cases large fluid flow channels
between the contacting metallic bodies, and large fluid leakage. However, in
most applications plastic deformation occurs, at least at the asperity level,
which allows the surfaces to approach each other to such an extent that fluid
leakage often can be neglected. In this study, we present an experimental
set-up for studying the fluid leakage in metallic seals. We study the water
leakage between a steel sphere and a steel body (seat) with a conical surface.
The experimental results are found to be in good quantitative agreement with a
(fitting-parameter-free) theoretical model. The theory predicts that the
plastic deformations reduce the leak-rate by a factor $\approx 8$

12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an