Environmentally Friendly Single-Wafer Spin Cleaning Using Ultra-diluted HF/Nitrogen Jet Spray without Causing Structural Damage and Material Loss

Structural health monitoring is an important safety factor in aviation that might benefit from advanced smart systems for damage sensing. This paper presents a new concept for a wireless crack and corrosion detection system for onboard health monitoring of aircraft. The sensor which is use to identify the structural damage and material loss on the surface of the aircraft by Ferrous Fluid under magnetic field. The Ferro fluid shall be applied as an emulsion on the test substrate. When a crack occurs, due to the crack there will a flux leakage. By constantly monitoring the flux on the surface of the substrate, whenever there is a flux leakage we can correlate it to a crack. The Ferro fluid shall be a ferromagnetic material and the particles should be in sub micron or nanometer region. These particles shall be mixed in suitable surfactants to get a uniformly monodispersed emulsion. This emulsion is to be applied on the test substrate and then the flux generated due to the emulsion shall be first measured. This measured flux density shall be taken as the baseline. Any deviation from the baseline shall be considered as flux leakage. It is possible to differentiate between the signals received from a crack and corrosion. One of the advantages of the present set up using Ferrous Fluid Sensor (FFS) for the generation and detection of signals can be easily processed by wireless application. The signal sensed by the FFS is transmitted to the cockpit through the wireless sensor network for monitoring of crack and corrosion on the surface of the aircraft.

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Evaluation of single-electron movies of glutamine synthetase molecules

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075191 ◽

1983 ◽

Vol 41 ◽

pp. 280-281

Author(s):

W. Kunath ◽

E. Zeitler ◽

M. Kessel

Keyword(s):

Electron Microscope ◽

Glutamine Synthetase ◽

Electron Irradiation ◽

Structural Damage ◽

Structural Changes ◽

Single Electron ◽

Continuous Series ◽

Digital Recording ◽

Recording Device ◽

Low Exposure

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.

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Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053188 ◽

1982 ◽

Vol 40 ◽

pp. 78-79

Author(s):

Kenneth H. Downing ◽

Robert M. Glaeser

Keyword(s):

Electron Beam ◽

Fatty Acid ◽

Inelastic Scattering ◽

Temperature Dependence ◽

Structural Damage ◽

Direct Result ◽

Second Step ◽

Strong Temperature Dependence ◽

Electron Dose ◽

Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

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Modification of the Electron Microscope for Investigation of Fully Hydrated Biological Specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064001 ◽

1969 ◽

Vol 27 ◽

pp. 418-419 ◽

Cited By ~ 2

Author(s):

R. C. Moretz ◽

D. F. Parsons

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Structural Damage ◽

Lower Percentage ◽

Vacuum Drying ◽

Total Removal ◽

Total Absence ◽

Biological Studies ◽

Electron Microscopes ◽

Beam Damage

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.

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Slow-scan CCD cameras and low-dose High-Resolution Electron Microscopy: Direct and quantitative

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169791 ◽

1994 ◽

Vol 52 ◽

pp. 412-413

Author(s):

M. Pan

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Structural Damage ◽

Low Dose ◽

Dynamic Range ◽

High Resolution Electron Microscopy ◽

Operating Conditions ◽

Digital Data ◽

Ccd Cameras ◽

Resolution Electron

It has been known for many years that materials such as zeolites, polymers, and biological specimens have crystalline structures that are vulnerable to electron beam irradiation. This radiation damage severely restrains the use of high resolution electron microscopy (HREM). As a result, structural characterization of these materials using HREM techniques becomes difficult and challenging. The emergence of slow-scan CCD cameras in recent years has made it possible to record high resolution (∽2Å) structural images with low beam intensity before any apparent structural damage occurs. Among the many ideal properties of slow-scan CCD cameras, the low readout noise and digital recording allow for low-dose HREM to be carried out in an efficient and quantitative way. For example, the image quality (or resolution) can be readily evaluated on-line at the microscope and this information can then be used to optimize the operating conditions, thus ensuring that high quality images are recorded. Since slow-scan CCD cameras output (undistorted) digital data within the large dynamic range (103-104), they are ideal for quantitative electron diffraction and microscopy.

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