Some factors affecting penetration in laser welding

1984 ◽  
Author(s):  
D. W. Moon
Keyword(s):  
Laser Welding ◽  
Factors Affecting

Rainbow Test of Laser Reconditioned Frame 6 Buckets

2003 ◽  
Author(s):  
M. C. van Beek ◽  
M. G. H. M. Hendriks ◽  
D. C. M. Wilms
Keyword(s):  
Laser Welding ◽  
Gas Turbines ◽  
Filler Metal ◽  
Welding Process ◽  
Maintenance Cost ◽  
Factors Affecting ◽  
The Difference ◽  
Lower Temperature ◽  
Filler Metals ◽  
Laser Welding Process

The procurement and reconditioning of turbine buckets and vanes drive the maintenance cost for gas turbines. The use of advanced repair methods like laser welding can help to reduce these costs. The main advantage of the laser welding process is that high-grade filler metals can be used with the possibility to extend current repair-limits. Before the laser welding process can be applied for industrial repairs the method has to be extensively tested for attained mechanical properties and for the performance during exposure in an actual turbine. This paper discusses the first rainbow test as performed on a frame 6 gas turbine of the Bergum power plant in the Netherlands. For a set of first stage buckets with 12139 operating hours (OH) 6 buckets were reconditioned using conventional TIG repair and 6 buckets using the laser-powder welding process. In both cases In 625 was used as the filler metal. The remaining buckets were not reconditioned. Monitoring of the performance of the reconditioned buckets is done using pyrometry and by boroscopic inspections. The reconditioned buckets are about 17°C cooler than the others. Moreover, it is found that the buckets repaired using laser welding have lower tip temperatures compared to the buckets reconditioned using conventional TIG welding. The overall lower temperature is partly caused by the difference in colour between the reconditioned and non-reconditioned buckets, which affects the emissivity. This difference was found still present during a boroscopic inspection 1776 OH after the overhaul. The other possible factors affecting the temperature difference are identified but are not yet fully understood.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

Factors affecting dentist participation in a state Medicaid program

1990 ◽  
Vol 54 (11) ◽  
pp. 638-643 ◽  
Author(s):  
PC Damiano ◽  
ER Brown ◽  
JD Johnson ◽  
JP Scheetz
Keyword(s):  
Medicaid Program ◽  
Factors Affecting

Speech Therapy Services in a Large School System: A Six-Year Overview

1976 ◽  
Vol 7 (4) ◽  
pp. 207-219 ◽  
Author(s):  
Constance P. DesRoches
Keyword(s):  
School System ◽  
Speech Therapy ◽  
Factors Affecting ◽  
Case Load ◽  
Number Of Children ◽  
School Population ◽  
System A ◽  
Therapy Services ◽  
And Shifts ◽  
Selection Factors

A statistical review provides analysis of four years of speech therapy services of a suburban school system which can be used for comparison with other school system programs. Included are data on the percentages of the school population enrolled in therapy, the categories of disabilities and the number of children in each category, the sex and grade-level distribution of those in therapy, and shifts in case-load selection. Factors affecting changes in case-load profiles are identified and discussed.

Assessing the Link Between Perception and Production in Cantonese Tone Acquisition

2019 ◽  
Vol 62 (5) ◽  
pp. 1243-1257 ◽  
Author(s):  
Peggy Pik Ki Mok ◽  
Holly Sze Ho Fung ◽  
Vivian Guo Li
Keyword(s):  
Language Acquisition ◽  
General Principle ◽  
Choice Task ◽  
Factors Affecting ◽  
Tone Pair ◽  
Tone Production ◽  
Monosyllabic Words ◽  
Early Production ◽  
Forced Choice Task ◽  
Production Accuracy

Purpose Previous studies showed early production precedes late perception in Cantonese tone acquisition, contrary to the general principle that perception precedes production in child language. How tone production and perception are linked in 1st language acquisition remains largely unknown. Our study revisited the acquisition of tone in Cantonese-speaking children, exploring the possible link between production and perception in 1st language acquisition. Method One hundred eleven Cantonese-speaking children aged between 2;0 and 6;0 (years;months) and 10 adolescent reference speakers participated in tone production and perception experiments. Production materials with 30 monosyllabic words were transcribed in filtered and unfiltered conditions by 2 native judges. Perception accuracy was based on a 2-alternative forced-choice task with pictures covering all possible tone pair contrasts. Results Children's accuracy of production and perception of all the 6 Cantonese tones was still not adultlike by age 6;0. Both production and perception accuracies matured with age. A weak positive link was found between the 2 accuracies. Mother's native language contributed to children's production accuracy. Conclusions Our findings show that production and perception abilities are associated in tone acquisition. Further study is needed to explore factors affecting production accuracy in children. Supplemental Material https://doi.org/10.23641/asha.7960826

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