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Number of results: 4
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Abstract

To determine the relationships between operating conditions and tribological properties of Zn-30Al-3Cu alloy, its wear characteristics were investigated at wide ranges of oil flow rate, pressure and sliding velocity using a block-on-disk type test apparatus. The results are compared to those of SAE 660 leaded bearing bronze. Wear loss of these materials increased with sliding distance, pressure and sliding velocity, but decreased slightly with oil flow rate. The relationships between operating conditions and lubricated wear properties of Zn-30Al-3Cu alloy were determined by nonlinear regression analysis of the experimental data. Lubricated wear behavior of the zinc-based alloy was discussed in terms its microstructure and mechanical properties, and test conditions.
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Authors and Affiliations

Temel Savaşkan
1
ORCID: ORCID
Hasan Onur Tan
2
ORCID: ORCID

  1. Haliç University, Department of Mechanical Engineering, 34060 Eyüpsultan, Istanbul, Turkey
  2. Giresun University, Department of Mechanical Engineering, 28200, Giresun, Turkey
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Abstract

A new attack against the Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system is studied with unknown parasitic DC-voltage sources at both Alice’s and Bob’s ends. This paper is the generalization of our earlier investigation with a single-end parasitic source. Under the assumption that Eve does not know the values of the parasitic sources, a new attack, utilizing the current generated by the parasitic dc-voltage sources, is introduced. The attack is mathematically analyzed and demonstrated by computer simulations. Simple defense methods against the attack are shown. The earlier defense method based solely on the comparison of current/voltage data at Alice’s and Bob’s terminals is useless here since the wire currents and voltages are equal at both ends. However, the more expensive version of the earlier defense method, which is based on in-situ system simulation and comparison with measurements, works efficiently.

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Authors and Affiliations

Mutaz Y. Melhem
Laszlo B. Kish
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Abstract

The paper presents a method of structural monitoring using measurement of vertical displacements realized optically by horizontally directed laser beam. A measuring device with an integrated rangefinder and inclinometer sensor was developed. Inclinometer sensor are used to correct measurement results of the rangefinder in order to eliminate errors resulting from spatial position changes of the laser beam. Such a solution was adopted as an alternative to a more complex and demanding method, which is the stabilization of the laser beam orientation. The proposed inclinometric correction method allows in a simple and clear way to eliminate a serious problem of the displacement measurement method with a perpendicularly directed laser beam, which is inevitable in practice the lack of permanent stability of the measuring device position. The developed measuring device is wireless, both in terms of power supply and communication with other elements of the monitoring system. In order to verify the correctness of measurements carried out by the developed device, on site tests were carried out in two industrial-warehouse buildings with functioning monitoring systems using other measurement methods, earlier verified. The tests confirmed compliance with the indications of the existing system at a level completely sufficient for structural monitoring system purposes. The conducted research show that the proposed method of displacements measurement with inclinometric correction of errors, provides accurate and reliable results, allowing also to obtain additional information about the behaviour of the structure in the place of installation of the measuring device.
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Authors and Affiliations

Stanisław Wierzbicki
1
ORCID: ORCID
Zbigniew Pióro
2 3
Marcin Osiniak
3

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
  2. Warsaw University of Technology, Faculty of Electronics and Information Technology, Nowowiejska15/19, 00-665 Warsaw (retired professor)
  3. WiSeNe Sp. z o.o., Taneczna 27, 02-829 Warsaw, Poland
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Abstract

Polymer-based capacitive humidity sensors emerged around 40 years ago; nevertheless, they currently constitute large part of sensors’ market within a range of medium (climatic and industrial) humidity 20−80%RH due to their linearity, stability and cost-effectiveness. However, for low humidity values (0−20%RH) that type of sensor exhibits increasingly nonlinear characteristics with decreasing of humidity values. This paper presents the results of some experimental trials of CMOS polymer-based capacitive humidity sensors, as well as of modelling the behaviour of that type of sensor. A logarithmic functional relationship between the relative humidity and the change of sensor output value at low humidity is suggested.

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Authors and Affiliations

Jacek Majewski

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