scholarly journals Testing of Ceramic Stator Vanes to 2500 F (1371 C)

1975 ◽  
Author(s):  
A. N. Holden ◽  
S. E. Mumford ◽  
C. R. Booher
Keyword(s):  
Power Generation ◽  
Cyclic Tests ◽  
Full Size ◽  
Test Conditions ◽  
Edge Loading ◽  
End Caps ◽  
Complete Failure

Ceramic inlet vanes were tested in a full-size, eight-vane cascade rig to simulate power generation operation at 2200 and 2500 F (1204 and 1371 C). The 2200 F (1204 C) test, using only Si3N2 vanes, successfully completed over 100 start/stop cycles, except for some out-of-tolerance parts that caused edge loading. Initial 2500 F (1371 C) tests resulted in complete failure of the four carbide parts, while the four nitride parts remained funtional. Ramps up and down were somewhat more severe than for normal turbine operation, and all parts received debris impaction from an imploded combustor. Minor cracking occurred in only one nitride airfoil and two different nitride end caps. All LAS CERVIT C-140 insulator material was badly cracked after both test conditions. New insulator materials are being evaluated and cyclic tests are continuing.

A discussion on advanced methods of energy conversion- Magnetohydrodynamic power generation - First results of the Électricité de France 8 MW m.h.d. experimental rig at Centre de Recherches et d’Essais des Renardieres

1967 ◽  
Vol 261 (1123) ◽  
pp. 401-428 ◽  
Keyword(s):  
Power Generation ◽  
First Year ◽  
Experimental Plant ◽  
Correct Interpretation ◽  
Paper Briefly ◽  
Research Teams ◽  
Full Size ◽  
Physical Conditions ◽  
First Results ◽  
Experimental Rig

During its first year of service the m.h.d. experimental rig at Renardieres has been used for various studies on the performance of different sized m.h.d. generators and of the technology of electrodes and insulating walls. However, these experiments are not yet finished, and this report aims only at describing the present state of the most interesting studies and at comparing the results with those published by other research teams. The paper briefly describes the characteristics of the experimental plant and the conditions under which m.h.d. experiments have been carried out. Changes in the electrical and physical conditions of ionized gases during their passage through the test section have been studied, as a knowledge of these conditions is necessary for the correct interpretation of conditions in full size m.h.d. generators. Studies on m.h.d. generator materials have included insulating walls, ‘hot’ electrodes and ‘ cold ’ electrodes. However, only the studies on ‘ cold ’ electrodes are reported in detail as they are the most advanced to date; the studies on ‘ hot ’ electrodes have not progressed far, and for insulating walls, the use of cold ' peg walls ’ developed by Avco has been adopted. Finally some results of studies on generator operation are discussed.

Wheel-Rail Contact Characteristics on a Tangent Track Vs a Roller Rig

2012 ◽  
Author(s):  
Alexander Keylin ◽  
Mehdi Ahmadian ◽  
Mehdi Taheri ◽  
Ali Tajaddini
Keyword(s):  
Contact Mechanics ◽  
Surface Condition ◽  
Field Testing ◽  
Test Results ◽  
Full Size ◽  
Test Conditions ◽  
Roller Rig ◽  
Analytical Expressions ◽  
Roller Radius ◽  
Track Irregularities

This study derives explicit analytical expressions for comparing contact patch dimensions and Kalker’s coefficients for a wheel moving on a roller and compares the results with a tangent track arrangement. The expressions suggest that full size roller rig will underpredict Kalker’s traction coefficients (creepage forces per unit creepage) by a factor that depends on the roller radius. Studying rail-wheel contact mechanics and dynamics in the field conditions can prove to be challenging due to the difficulties in adequately controlling the test conditions that can significantly affect the results, such as track irregularities, rail surface condition, etc. Roller rigs can prove to be a useful tool for such studies. One, however, must be careful when interpreting roller rig test results because of the differences in wheel-rail contact mechanics and dynamics between the track and the roller. The findings of this study, which are consistent with other studies’ conclusions, will allow researchers to relate results with field testing.

THE EXPERIMENTAL THERMAL BEHAVIOR OF AN ANNULAR STRUCTURE

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4589-4594
Author(s):  
JEONG-KI HWANG ◽  
CHANG-MIN SUH ◽  
CHAE-HO KIM
Keyword(s):  
Structural Model ◽  
Cyclic Loads ◽  
Temperature Profiles ◽  
Model Design ◽  
Penetration Test ◽  
Cyclic Tests ◽  
Crack Initiation And Propagation ◽  
Test Conditions ◽  
Annular Structure ◽  
Initiation And Propagation

A half-scaled large structural model for an annular structure was built, and its behaviors were tested and obtained by thermal cyclic loads. The model design and test conditions were determined to take into consideration the thermal and mechanical loads acting on the annular structure by numerical methods. Temperature profiles and strains of the flexure were measured during the test. After completion of the thermal cyclic tests, no evidence of crack initiation and propagation were identified by a dye penetration test.

scholarly journals Research on simulation and test analysis of hydraulic transient process in Jinping II Hydropower Station

2021 ◽  
Vol 248 ◽  
pp. 02068
Author(s):  
Cao Chun-jian ◽  
Fang Jie ◽  
Chen Shun-yi ◽  
Huang Jing-qian
Keyword(s):  
Power Generation ◽  
Simulation Model ◽  
Water Diversion ◽  
Hydropower Station ◽  
Generation System ◽  
Hydraulic Transient ◽  
Test Conditions ◽  
Jinping Ii Hydropower Station ◽  
Power Generation System ◽  
Large Water

The paper takes Jinping II Hydropower Station (8 × 600MW) as an example based on the internal mechanism and operating characteristics of the system, the complete simulation model of the super-long and large water diversion and power generation system has been completed finally.Besides, the method of parameter calibration and correction for the main elements of the system is proposed.By the simulation model, two typical hydraulic transient process test conditions are simulated, here the involved test conditions are as following: double load rejection and primary frequency regulation.At the same time, the calculated results are compared with the test results. The results show that the proposed simulation model can describe the dynamic response characteristic of the super-long and large water diversion and power generation system accurately.

scholarly journals Simulator Study of MOM using Steep-cup Flexion - A Clinically Relevant Incorporation of Intermittent Edge-loading

2017 ◽  
Vol 7 (3) ◽  
Author(s):  
Ian Clarke ◽  
Julia Shelton ◽  
John Bowsher ◽  
Christina Savisaar ◽  
Thomas Donaldson
Keyword(s):  
Loading Test ◽  
Wear Area ◽  
Normal Loading ◽  
Wear Rates ◽  
Test Conditions ◽  
Hip Simulator ◽  
Test Parameters ◽  
Metal On Metal ◽  
Edge Loading

Background: Adverse-wear phenomenon in metal-on-metal (MOM) arthroplasty has been attributed to “edge-loading” of the CoCr cups. Simulator studies of steeply-inclined cups run in the ‘Anatomic-cup’ model represented many variations in design and test parameters with no coherent rationale. We created an algorithm to synthesize MOM test parameters and noted that wear areas typically averaged only 10-15% of cup surface. In contrast, retrievals showed wear areas extending to 60% of cup surface. We hypothesized that MOM wear studies run in the orbital hip simulator with the ‘Inverted-cup’ model would, (i) differentiate normal-loading versus edge-loading, (ii) demonstrate cup wear areas x3.8-times larger than on femoral heads, cover 30% of cup surface, and (iii) double the wear-rates measured in prior Anatomic-cup study.Methods: Edge-loading occurs when the cup rim is allowed to truncate the habitual wear area that provides optimal tribological conditions. A MOM algorithm was developed to synthesize relevant test parameters. The 60mm MOM bearings donated for this study were run in an orbital hip simulator using the Inverted-cup model. Tests #1 and #2 to one million cycles (1-Mc) duration assessed wear at peak cup inclinations 40° and 50°. Test #3 evaluated edge-loading with peak cup inclinations achieving 70° (5-Mc duration).Results: Wear areas in Inverted-cups averaged 1663mm2 in tests #1 and 2, were fully contained within cup rims, and covered 30% of cup surface as predicted by algorithm. Test-3 with 70° cup inclination produced the predicted edge-loading with volumetric wear-rates averaging 2mm3/Mc, approximately 5-fold greater wear than prior Anatomic-cup study.Discussion and Conclusions: Simulator studies of steep-cup mechanisms necessitate production of clinically-relevant wear-patterns such that the biomechanical and tribological functionality is respected. As an aid to steeply-inclined cup analyses, the MOM algorithm allowed integration of confounding test parameters. The algorithm successfully differentiated between “normal” and “edge loaded” cups and the MOM wear areas were as predicted for three cup inclinations. Also as predicted, wear-patterns in Inverted-cup model exactly reversed those of the Anatomic-cup model. Even with only intermittent edge-loading, Test-3 produced 5-fold greater wear than our prior Anatomic study.Clinical Significance: The Inverted-cup simulator model successfully mobilized the cup to produce larger wear areas that were more representative of those in-vivo and therefore reproduced more realistic test conditions for studies of edge-loaded cups.

Micro photosynthetic power cell for power generation from photosynthesis of algae

TECHNOLOGY ◽  
2015 ◽  
Vol 03 (02n03) ◽  
pp. 119-126 ◽  
Author(s):  
Mehdi Shahparnia ◽  
Muthukumaran Packirisamy ◽  
Philippe Juneau ◽  
Valter Zazubovich
Keyword(s):  
Power Generation ◽  
Current Density ◽  
External Load ◽  
Alternative Energy ◽  
Peak Power ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Blue Green Algae ◽  
Power Cell ◽  
Test Conditions

Devices such as solar and fuel cells have been studied for many decades and noticeable improvements have been achieved. This paper proposes a Micro Photosynthetic Power Cell (μPSC) as an alternative energy-harvesting device based on photosynthesis of blue-green algae. The effect of important biodesign parameters on the performance of the device, such as no-load performance and voltage–current (V–I) characteristics, were studied. Open-circuit voltage as high as 993 mV was measured while a peak power of 175.37 μW was obtained under an external load of 850 Ω. The proposed μPSC device could produce a power density of 36.23 μW/cm2, voltage density of 80 mV/cm2 and current density of 93.38 μA/cm2 under test conditions.

Effects of Fundamental Frequency Contours on Sentence Recognition in Mandarin-Speaking Children With Cochlear Implants

2020 ◽  
Vol 63 (11) ◽  
pp. 3855-3864
Author(s):  
Wanting Huang ◽  
Lena L. N. Wong ◽  
Fei Chen ◽  
Haihong Liu ◽  
Wei Liang
Keyword(s):  
Cochlear Implants ◽  
Fundamental Frequency ◽  
Signal To Noise Ratio ◽  
Lexical Tone ◽  
Signal To Noise ◽  
Sentence Recognition ◽  
Test Conditions ◽  
Age Appropriate ◽  
F0 Contour ◽  
Appropriate Sentences

Purpose Fundamental frequency (F0) is the primary acoustic cue for lexical tone perception in tonal languages but is processed in a limited way in cochlear implant (CI) systems. The aim of this study was to evaluate the importance of F0 contours in sentence recognition in Mandarin-speaking children with CIs and find out whether it is similar to/different from that in age-matched normal-hearing (NH) peers. Method Age-appropriate sentences, with F0 contours manipulated to be either natural or flattened, were randomly presented to preschool children with CIs and their age-matched peers with NH under three test conditions: in quiet, in white noise, and with competing sentences at 0 dB signal-to-noise ratio. Results The neutralization of F0 contours resulted in a significant reduction in sentence recognition. While this was seen only in noise conditions among NH children, it was observed throughout all test conditions among children with CIs. Moreover, the F0 contour-induced accuracy reduction ratios (i.e., the reduction in sentence recognition resulting from the neutralization of F0 contours compared to the normal F0 condition) were significantly greater in children with CIs than in NH children in all test conditions. Conclusions F0 contours play a major role in sentence recognition in both quiet and noise among pediatric implantees, and the contribution of the F0 contour is even more salient than that in age-matched NH children. These results also suggest that there may be differences between children with CIs and NH children in how F0 contours are processed.

Bipolar radiofrequency induced thermotherapy and 1064 nm Nd:Yag laser in endovenous occlusion of insufficient veins: short term follow up results

VASA ◽  
2011 ◽  
Vol 40 (3) ◽  
pp. 235-240 ◽  
Author(s):  
Krnic ◽  
Sucic
Keyword(s):  
Side Effects ◽  
Success Rate ◽  
Nd:Yag Laser ◽  
Main Stem ◽  
Short Term ◽  
Main Trunk ◽  
Bipolar Radiofrequency ◽  
Saphenous Veins ◽  
Skin Redness ◽  
Complete Failure

Background: The aim of this study is to report our results in main stem vein closure using the bipolar radiofrequency induced thermotherapy (RFITT) system and the 1064nm Nd:Yag laser. Patients and methods: 44 incompetent main stem veins (37 great saphenous veins, one lesser saphenous vein, and 6 anterior accessory saphenous veins) in 29 patients were treated using RFITT. 53 incompetent main stem veins (45 great saphenous veins, 4 lesser saphenous veins, and 4 anterior accessory saphenous veins) in 43 patients were treated endovenously with 1064 nm Nd:Yag laser. All patients underwent postoperative duplex scanning within a month after procedure, as well as a short interview regarding postoperative discomfort. Results: In main stem veins treated with RFITT, the success rate within the first month was 86,4 % (38 out of 44 veins). Complete failure rate was 13,6 % (6 out of 44 veins). In 53 main stem veins treated by 1064 nm Nd:Yag laser, the success rate was 100 %, consisting of 98,1 % complete success (52/53 veins), and 1,9 % partial success (1/53 veins). None of the patients treated with RFITT experienced postoperative adverse effects, whereas 13/43 (30,2 %) patients treated with laser had to use oral analgesics after the treatment, and 21/43 (48,8 %) patients reported transient skin changes, such as bruising or skin redness. Conclusions: RFITT system was fairly efficient in the short term for closure of main trunk veins, whereas longer term results are still scarce. Postoperative side effects of RFITT were minimal. 1064nm Nd:Yag laser, according to short term results, proved to be very effective for main stem vein closure. Postoperative side effects related to 1064 nm Nd:Yag endovenous laser treatment proved to be minor, transient, and acceptable.

Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment

2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Line Length ◽  
Perceptual Cues ◽  
Virtual Reality Environment ◽  
Top Down ◽  
Test Conditions ◽  
The Subject ◽  
Processing Mechanisms

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.

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