scholarly journals Acoustic Journal Bearing With Changeable Geometry and Built-in Flexibility

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
T. A. Stolarski ◽  
M. Miyatake
Keyword(s):  
Performance Assessment ◽  
Journal Bearing ◽  
Squeeze Film ◽  
Film Pressure ◽  
Motion Stability ◽  
Start Up ◽  
Fatigue Endurance ◽  
Better Than

The influence of embodiment flexibility on the performance of an acoustic journal bearing is presented. Two completely different embodiments of the bearing were investigated using three criteria of performance assessment that is torque at the start-up, amount of separation due to squeeze film pressure, and motion stability of the shaft running at speed. The embodiment with built-in flexibility proved to perform far better than the bearing for which overall flexibility was much less. However, considerations pertinent to the easy of machining and fatigue endurance mitigate the ranking of performance of the two embodiments investigated.

scholarly journals Running Characteristics of Aerodynamic Bearing with Self-Lifting Capability at Low Rotational Speed

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Tadeusz Adam Stolarski
Keyword(s):  
Fourier Transform ◽  
Journal Bearing ◽  
Static Model ◽  
The Self ◽  
Experimental Results ◽  
Squeeze Film ◽  
Film Pressure ◽  
Squeeze Film Effect ◽  
Time Marching ◽  
The Stability

An aerodynamic journal bearing that is capable of self-generating squeeze-film pressure is presented and its dynamic characteristics investigated numerically and experimentally. A numerical method based on a time-marching static model was applied to assess the orbit trajectory path of the rotor upon a perturbation. Experimental results were obtained to validate the effect of the self-generated squeeze-film pressure on the stability of the rotor. Analyzing the Fast Fourier Transform (FFT) responses of the rotor orbits enabled identification of self-excited whirling instabilities. Both numerical and experimental results showed that increasing the squeeze-film effect of the bearing could raise the threshold speed of instability.

Contextual Learning Approach and Performance Assessment in Mathematics Learning

2016 ◽  
Vol 3 (3) ◽  
Author(s):  
I Wayan Eka Mahendra
Keyword(s):  
Formative Assessment ◽  
Performance Assessment ◽  
Junior High School ◽  
Mathematics Learning ◽  
Sampling Technique ◽  
Learning Outcome ◽  
Contextual Learning ◽  
Learning Approach ◽  
Better Than ◽  
A Performance

This study aims to determine the effect of formative assessment and learning approach to the mathematics learning outcome after controlling the numerical aptitude. It was a quasi-experiment with a sample of 186 students obtained by using multistage random sampling technique with 2x2 factorial designs. The data were analyzed by ANCOVA. After controlling the numerical aptitude, the results are: the mathematics learning outcome of the students who followed a contextual approach was better than the ones who followed a conventional learning approach, the mathematics learning outcome of the students who were given a performance assessment was better than the ones who were given a conventional assessment, the interaction between the learning approach and formative assessment affected the students learning outcome for mathematics, the students who followed a contextual learning approach were more suitable to be given a performance assessment, whereas the ones who followed a conventional learning approach were more appropriate to be given a conventional assessment. Based on the research findings, junior high school teachers are suggested to improve their students learning outcome for mathematics. Then, teachers need to use a learning approach and formative assessment accurately and correctly. 

Numerical investigation of dynamic and hydrodynamic characteristics of the pad in the fluid pivot journal bearing

2021 ◽  
pp. 135065012110330
Author(s):  
Tuyen Vu Nguyen ◽  
Weiguang Li
Keyword(s):  
Computational Models ◽  
Journal Bearing ◽  
Squeeze Film ◽  
Hydrodynamic Characteristics ◽  
Hydrodynamic Properties ◽  
Squeeze Film Damper ◽  
Lubricant Oil ◽  
Oil Flow ◽  
Flow Through ◽  
Bearing System

The dynamic and hydrodynamic properties of the pad in the fluid pivot journal bearing are investigated in this paper. Preload coefficients, recess area, and size gap, which were selected as input parameters to investigate, are important parameters of fluid pivot journal bearing. The pad’s pendulum angle, lubricant oil flow through the gap, and recess pressure which characterizes the squeeze film damper were investigated with different preload coefficients, recess area, and gap sizes. The computational models were established and numerical methods were used to determine the equilibrium position of the shaft-bearing system. Since then, the pendulum angle of the pad, liquid flow, and recess pressure were determined by different eccentricities.

scholarly journals PENGARUH IMPLEMENTASI ASESMEN OTENTIK DALAM PEMBELAJARAN TERHADAP HASIL BELAJAR GAMBAR TEKNIK DENGAN PENGENDALIAN BAKAT MEKANIK DI KELAS X TKRO SMK NEGERI 3 SINGARAJA

2019 ◽  
Vol 9 (2) ◽  
pp. 58-69
Author(s):  
Gede Aprianto ◽  
I Made Candiasa ◽  
I Made Gita
Keyword(s):  
Performance Assessment ◽  
Random Sampling ◽  
Sampling Technique ◽  
Authentic Assessment ◽  
Single Factor ◽  
Learning Achievement ◽  
Project Assessment ◽  
Technical Drawing ◽  
Quasi Experimental ◽  
Better Than

AbstrakTujuan utama penelitian ini adalah untuk mengetahui pengaruh implementasi asesmen otentik yang terdiri dari asesmen proyek dan asesmen kinerja terhadap hasil belajar gambar teknik dengan pengendalian bakat mekanik yang dilakukan di kelas X TKRO SMK Negeri 3 Singaraja. Penelitian ini merupakan jenis quasi experiment dengan rancangan single factor independent groups design with use covariate. Sampel penelitian berjumlah 70 orang siswa yang diambil menggunakan teknik random sampling. Pengumpulan data dilakukan dengan metode tes obyektif dan uraian. Hipotesis pada penelitian ini diuji dengan Anakova satu jalur. Hasil penelitian menunjukkan bahwa : Pertama, hasil belajar gambar teknik siswa yang diberi penerapan asesmen proyek lebih baik daripada siswa yang diberi penerapan asesmen kinerja (thit = 2,303; p ≤ 0,05). Kedua, setelah dilakukan pengendalian terhadap bakat mekanik, hasil belajar gambar teknik siswa yang diberi penerapan asesmen proyek lebih baik daripada hasil belajar siswa yang diberi penerapan asesmen kinerja (Fhit = 49,204; p ≤ 0,05). Ketiga, terdapat kontribusi bakat mekanik (86,2%) terhadap hasil belajar gambar teknik (R = 0,929; thit = 20,620; p ≤ 0,05). Atas temuan tersebut, disimpulkan bahwa asesmen proyek dan bakat mekanik mempunyai pengaruh terhadap hasil belajar gambar teknik pada siswa kelas X TKRO SMK Negeri 3 Singaraja. Kata kunci: asesmen otentik, hasil belajar gambar teknik, bakat mekanik AbstractThe main objective of this study was to determine the effect of authentic assessment implementation consisting of project assessment and performance assessment towards the technical drawing learning achievement by controlling mechanical talent in X TKRO class at SMK Negeri 3 Singaraja. The study employed a quasi-experimental type with a single factor design independent groups design with use covariate. There were 70 students as the samples of the study that determined by random sampling technique. The data were obtained through objective test and essay method. The hypothesis in this study was tested by a one-way Ancova. The results showed that: a) the technical drawing learning achievement of the students that applied project assessment were better than the learning achievement of students who were applied performance assessment (thit= 2.303; p ≤ 0.05), b) after controlling for mechanical talent, the technical drawing learning achievement of the students applied project assessment were better than the students who applied performance assessment (Fhit = 49.204; p ≤ 0.05), c) there was a contribution of mechanical talent (86.2%) to the technical drawing learning achievement (R = 0.929; thit = 20.620; p ≤ 0.05). Based on these findings, it was concluded that project assessment and mechanical talent had an influence on the technical drawing learning achievement of X TKRO class at SMK Negeri 3 Singaraja. Keywords: authentic assessment, technical drawing learning achievement, mechanical talent

Simulation studies on static thermal behaviour of true elliptical and orthogonally displaced non-circular journal bearing

2016 ◽  
Vol 68 (3) ◽  
pp. 349-360 ◽  
Author(s):  
Amit Singla ◽  
Amit Chauhan
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Current Trend ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Film Pressure ◽  
Content Type ◽  
Oil Film ◽  
Ellipticity Ratio ◽  
Oil Film Pressure

Purpose The current trend of modern industry is to use machineries which rotate at high speed along with the capability of carrying heavy rotor loads. This paper aims at static thermal analysis of two different profiles of non-circular journal bearings – a true elliptical bearing and orthogonal bearing. Design/methodology/approach The Reynolds equation has been solved through finite difference method to compute the oil film pressure. Parabolic temperature profile approximation technique has been used to solve the energy equation and thus used for computation of various bearing performance characteristics such as thermo-hydrodynamic oil film pressure, temperature, load capacity, Sommerfeld number and power loss characteristics across the bearing. The effect of ellipticity ratio on the bearing performance characteristics has also been obtained for both the elliptical and vertical offset bearing using three different commercially available grades of oil (Hydrol 32, 68 and 100). Findings It has been observed that the thermo-hydrodynamic pressure and temperature rise of the oil film is less in orthogonal bearing as compared to the true elliptical bearing for same operating conditions. The effect of ellipticity ratio of non-circularity on bearing performance parameters have been observed to be less in case of elliptical bearing as compared to orthogonal bearing. It has been concluded that though the rise in oil film temperature is high for true elliptical bearing, but still it should be preferred over orthogonal profile under study, as it has comparably good load-carrying capacity. Originality/value The performance parametric analysis will help the designers to select such kind of non-circular journal bearing for various applications.

scholarly journals Fuzzy Logic based Model to Predict Maximum Oil-Film Pressure in Journal Bearing

2013 ◽  
Vol 6 (20) ◽  
pp. 3871-3878 ◽  
Author(s):  
Diyar I. Ahmed ◽  
S. Kasolang ◽  
Basim A. Khidhir ◽  
B.F. Yousif
Keyword(s):  
Fuzzy Logic ◽  
Journal Bearing ◽  
Film Pressure ◽  
Oil Film ◽  
Oil Film Pressure

Development of CMOS Micromachined Capacitive Squeeze-Film Pressure Sensors

2020 ◽  
Vol 20 (17) ◽  
pp. 9698-9705
Author(s):  
Kuan-Yu Hsieh ◽  
Jason Chiu ◽  
Michael S.-C. Lu
Keyword(s):  
Pressure Sensors ◽  
Squeeze Film ◽  
Film Pressure

Dynamic Behavior of Pure Squeeze Films in Narrow Porous Bearings

1974 ◽  
Vol 96 (3) ◽  
pp. 361-364 ◽  
Author(s):  
P. R. K. Murti
Keyword(s):  
Dynamic Behavior ◽  
Cyclic Load ◽  
Journal Bearing ◽  
Load Capacity ◽  
Squeeze Film ◽  
Closed Form Expression ◽  
Cyclic Loads ◽  
Eccentricity Ratio ◽  
Form Expression ◽  
Bearing Material

The dynamic behavior of squeeze film in a narrow porous journal bearing under a cyclic load is analyzed. A thin-walled bearing with a nonrotating journal is considered and a closed form expression for the pressure distribution is derived. The locus of the journal center is found by numerical methods and it is established with an example that actual contact between the journal and bearing can be avoided by appropriate design of the bearing. Consequently, it is proved that pure squeeze films have a load capacity only under cyclic loads. The analysis also reveals that the permeability of the bearing material and the wall thickness of the bearing influence significantly the operating eccentricity ratio.

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