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Technical Paper

Further Development of Particulate Sensors for Mobile Use with the Aid of a Circuit Board

2020-10-05
2020-01-1638
In the last decade, pollution by particulate matter and its effect on human health has increasingly become the focus of public attention. In order to monitor and evaluate particulate pollution, expensive measuring stations were placed at traffic hotspots and other selected locations. The measuring devices often precisely record the particle concentration, but have disadvantages in mobility and for measurements in large-area due to their size and investment costs. A measurement with high temporal and spatial resolution is not possible with these stations. This paper presents a new type of mobile particulate sensor based on the Plantower PMS 7003 particle sensor. In addition to the Plantower sensor, a rechargeable battery and newly developed control electronics are also installed in the particulate sensor. Due to the small size and the low manufacturing costs of the measuring system, mobile usage in higher quantity is possible.
Technical Paper

An Experimental Setup for Investigations on the Boundary Layer Dynamics

2020-10-05
2020-01-1617
The frictional behavior of a tribological contact is influenced by the dynamics in the forming boundary layer. Recurring structures, built up through self-organizing effects, were found in various frictional systems. To investigate those phenomena on a macroscopic scale and to better understand dynamical processes such as the formation and decay of contact patches, the first revision of the Wear Debris Investigator (WDI) was introduced in 2017. A friction gap is formed between two coaxial horizontally arranged discs. To mimic the presence of particles, artificial wear dust is fed into the gap. With a camera the formation of the boundary layer is recorded in situ. An implemented normal force and torque sensor enables to recognize correlations between the formed boundary layer and the occurring frictional forces. Numerous measurements revealed an insufficient precision of the previous WDI.
Technical Paper

The Use of a Low Frequency Vibration Signal in Detecting the Misfire of a Cylinder of an Aircraft Piston Engine

2020-09-15
2020-01-2023
The article describes the low frequency vibration analysis of aircraft piston engine Rotax 912 ULS. The results are based on the vibration signal made by the engine in the frequency range up to 400 Hz measured on the engine block in three axes. The aim of the research was to determine the method of detecting the misfire of individual cylinders based on the power spectrum of the selected frequencies analysis. The analysis was based on the frequencies resulting from the cyclicality of engine operation related to the frequency of the operation cycle, rotational speed and ignition frequency. The tests were carried out in one point of operation. The highest levels of changes were recorded in the Y axis - the axis of piston movement. It was shown that the vibration level changes after switching off one of the cylinders.
Technical Paper

Determination of Kinematic Parameters for the Combustion of Jatropha Based Bio-Diesel

2020-09-15
2020-01-2148
Laminar burning velocity of bio-diesel air mixture has been studied in a spherical bomb, using the pressure – time records. I also varied initial pressure, temperature to cover a range from 1.013bar-4bar and 400k-500k respectively. The range of measurements covered the equivalence ratio from 0.8 to 1.2. Pressure-time records have been used to calculate the flame velocity, burned gas fraction, flame position etc., using a simplified, two zone thermodynamic model, assuming equilibrium composition and homogenous mixture for the burned gases. It is also assumed frozen composition and isentropic compression for the unburned mixture. For each experimental run, instantaneous burning velocities were calculated in the range of 1.5P0 to 0.75 P max and the laminar burning velocity values between the burned mass fraction of 0.2 and 0.3 were averaged to get burning velocity value for a particular experimental run.
Standard

Aerospace Rod Scraper Gland Design Standard

2020-07-22
WIP
AS4088F
This SAE Aerospace Standard (AS) defines gland details for scrapers for rod diameters from 1/4 to 15-1/2 inch (6.35 to 393.70 mm) inclusive, corresponding to AS568 O-ring Dash No. sizes -108/-111, -206/-222, -325/-349, and -425/-460. The gland details herein allow the use of more stable, efficient and reliable scraper devices than MS33675 glands. NOTE: Scraper configurations are not specified in this document.
Standard

Cab Sleeper Occupant Restraint System Test

2020-07-07
WIP
J1948
This SAE Recommended Practice provides a standardized test procedure for heavy-duty truck sleeper berth restraints to determine whether they meet the FMCSR 393.76(h) requirements.
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