Metallurgical Failure Analysis of an Axial Gas Flow Valve: The Erosion of Valve Cage Closures

2021 ◽  
Author(s):  
Sadegh Pour-Ali ◽  
Mohammadreza Etminanfar
Keyword(s):  
Failure Analysis ◽  
Gas Flow ◽  
Flow Valve

scholarly journals Failure Analysis of a Burner Component

1996 ◽  
Author(s):  
Kenneth L. Saunders ◽  
Brian P. Copley
Keyword(s):  
Temperature Distribution ◽  
Failure Analysis ◽  
Gas Flow ◽  
Operational Stress ◽  
Operational Conditions ◽  
Root Cause ◽  
Creep Region ◽  
Stress Levels ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

The cogeneration facility of interest contains four identical cogeneration units which produce about one half million Kg per hour of steam for an adjacent refinery and 385 megawatts of electricity. To supplement the production of steam, burners are used to heat the gas turbine exhaust. These burners incorporate shields to deflect exhaust gas flow around the flame base. In an effort to improve burner emissions of the units, the burner shield design was modified. This alteration resulted in gross deformation of the shields which interfered with combustion. A failure analysis of these components was conducted to ascertain the root cause of the observed behavior. Loads were estimated based upon operational conditions and material properties were obtained from the open literature. An evaluation was conducted to determine the temperature distribution first. This temperature distribution was then coupled with mechanical loading to obtain total operational stress levels. The stress levels at the observed temperatures clearly placed the material in the high strain rate (creep) region. The computed stress distribution confirmed the observed failure configuration. A new design was proposed to eliminate this failure mechanism. Detailed evaluations revealed that the new design, while a significant improvement, still operated near the creep region for the material.

A stabilized gas flow valve for an ion source

1970 ◽  
Vol 81 (1) ◽  
pp. 201
Author(s):  
J.R.J. Bennett ◽  
H.E. Walford
Keyword(s):  
Gas Flow ◽  
Ion Source ◽  
Flow Valve

A Greaseless Gas Flow Valve

1950 ◽  
Vol 21 (12) ◽  
pp. 1024-1025 ◽  
Author(s):  
R. E. Honig
Keyword(s):  
Gas Flow ◽  
Flow Valve

Five‐Branch Gas Flow Valve

1953 ◽  
Vol 24 (6) ◽  
pp. 464-464
Author(s):  
D. E. Nagle
Keyword(s):  
Gas Flow ◽  
Flow Valve

Failure Analysis With the Scanning Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 482-483
Author(s):  
John R. Devaney
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
High Reliability ◽  
Military Applications ◽  
Small Structure ◽  
Useful Life ◽  
Insight Into ◽  
Scanning Electron

Occasionally in history, an event may occur which has a profound influence on a technology. Such an event occurred when the scanning electron microscope became commercially available to industry in the mid 60's. Semiconductors were being increasingly used in high-reliability space and military applications both because of their small volume but, also, because of their inherent reliability. However, they did fail, both early in life and sometimes in middle or old age. Why they failed and how to prevent failure or prolong “useful life” was a worry which resulted in a blossoming of sophisticated failure analysis laboratories across the country. By 1966, the ability to build small structure integrated circuits was forging well ahead of techniques available to dissect and analyze these same failures. The arrival of the scanning electron microscope gave these analysts a new insight into failure mechanisms.

TEM evaluation of graded SixGe1-x heterolayers

1991 ◽  
Vol 49 ◽  
pp. 894-895
Author(s):  
N. David Theodore ◽  
Mamoru Tomozane ◽  
Ming Liaw
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Gas Flow ◽  
Field Effect Transistors ◽  
Chemical Vapor ◽  
Dark Field ◽  
Bipolar Transistors ◽  
Structural Quality ◽  
Weak Beam ◽  
Transmission Electron ◽  
And Behavior

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.

Using the scanning electron microscope for failure analysis of high density magnetic media

1987 ◽  
Vol 45 ◽  
pp. 392-393
Author(s):  
Evelyn R. Ackerman ◽  
Gary D. Burnett
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Analysis ◽  
High Density ◽  
Magnetic Media ◽  
Specific Data ◽  
Retrieval Systems ◽  
Operating Environments ◽  
The Media ◽  
Scanning Electron

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.

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