Digital imaging of the oil permeation mechanism in an oleophobic textile

2021 ◽  
pp. 004051752110069
Author(s):  
Gannian Zhang ◽  
Qinfa Zhang

Resistance of military clothing to oil permeation is important for effective protection against chemical warfare. In this paper, while a military textile is rendered oleophobic (oil contact angle ≈ 120°) through plasma-assisted deposition of perfluorodecyl acrylate (PFAC8), permeation of the textile by silicon oil is observed. Using high-definition digital imaging, we study the oil permeation dynamics, rationalize the permeation with a plausible mechanism and identify the threshold textile pore size for prevention of the permeation. We find that oil permeates defects of PFAC8 textiles. Our data suggests a linear variation for oil permeation volume ΔV with time t and implies a gravity-driving permeation mechanism. The mechanism comprises three stages involving merging and propagation of oil–yarn contact lines. The threshold pore size dm scales with σ/ P, where σ is the oil surface tension and P is the hydrostatic head exerted by the oil drop. The paper indicates the importance of an undamaged textile structure to ‘robust’ oil resistance.

2017 ◽  
pp. 1165-1198
Author(s):  
P. Geetha

Today digital imaging is widely used in every application around us like Internet, High Definition TeleVision (HDTV), satellite communications, fax transmission, and digital storage of movies and more, because it provide superior resolution and quality. Recently, medical imaging has begun to take advantage of digital technology, opening the way for advanced medical imaging and teleradiology. However, medical imaging requires storing, communicating and manipulating large amounts of digital data. Applying image compression reduces the storage requirements, network traffic, and therefore improves efficiency. This chapter provides the need for medical image compression; different approaches to image compression, emerging wavelet based lossy-lossless compression techniques, how the existing recent compression techniques work and also comparison of results. After completing this chapter, the reader should have an idea of how to increase the compression ratio and at the same time maintain the PSNR level compared to the existing techniques, desirable features of standard compression techniques such as embededness and progressive transmission, how these are very useful and much needed in the interactive teleradiology, telemedicine and telebrowsing applications.


Author(s):  
P. Geetha

Today digital imaging is widely used in every application around us like Internet, High Definition TeleVision (HDTV), satellite communications, fax transmission, and digital storage of movies and more, because it provide superior resolution and quality. Recently, medical imaging has begun to take advantage of digital technology, opening the way for advanced medical imaging and teleradiology. However, medical imaging requires storing, communicating and manipulating large amounts of digital data. Applying image compression reduces the storage requirements, network traffic, and therefore improves efficiency. This chapter provides the need for medical image compression; different approaches to image compression, emerging wavelet based lossy-lossless compression techniques, how the existing recent compression techniques work and also comparison of results. After completing this chapter, the reader should have an idea of how to increase the compression ratio and at the same time maintain the PSNR level compared to the existing techniques, desirable features of standard compression techniques such as embededness and progressive transmission, how these are very useful and much needed in the interactive teleradiology, telemedicine and telebrowsing applications.


Author(s):  
K. Tsuno ◽  
T. Honda ◽  
Y. Harada ◽  
M. Naruse

Developement of computer technology provides much improvements on electron microscopy, such as simulation of images, reconstruction of images and automatic controll of microscopes (auto-focussing and auto-correction of astigmatism) and design of electron microscope lenses by using a finite element method (FEM). In this investigation, procedures for simulating the optical properties of objective lenses of HREM and the characteristics of the new lens for HREM at 200 kV are described.The process for designing the objective lens is divided into three stages. Stage 1 is the process for estimating the optical properties of the lens. Firstly, calculation by FEM is made for simulating the axial magnetic field distributions Bzc of the lens. Secondly, electron ray trajectory is numerically calculated by using Bzc. And lastly, using Bzc and ray trajectory, spherical and chromatic aberration coefficients Cs and Cc are numerically calculated. Above calculations are repeated by changing the shape of lens until! to find an optimum aberration coefficients.


Author(s):  
Lawrence W. Ortiz ◽  
Bonnie L. Isom

A procedure is described for the quantitative transfer of fibers and particulates collected on membrane filters to electron microscope (EM) grids. Various Millipore MF filters (Millipore AA, HA, GS, and VM; 0.8, 0.45, 0.22 and 0.05 μm mean pore size) have been used with success. Observed particle losses have not been size dependent and have not exceeded 10%. With fibers (glass or asbestos) as the collected media this observed loss is approximately 3%.


Author(s):  
W. C. Bigelow ◽  
F. B. Drogosz ◽  
S. Nitschke

High vacuum systems with oil diffusion pumps usually have a pressure switch to protect against Insufficient cooling water; however, If left unattended for long periods of time, failure of the mechanical fore pump can occur with equally serious results. The device shown schematically in Fig. 1 has been found to give effective protection against both these failures, yet it is inexpensive and relatively simple to build and operate.With this system, pressure in the fore pump line is measured by thermocouple vacuum gage TVG (CVC G.TC-004) whose output is monitored by meter relay MRy (Weston 1092 Sensitrol) which is set to close if the pressure rises above about 0.2 torr. This energizes control relay CRy (Potter & Brumfield KA5Y 120VAC SPDT) cutting off power to solenoid-operated fore line valve Vf (Cenco 94280-4 Norm. Closed) which closes to prevent further leakage of air into the diffusion pump


Author(s):  
W.A. Carrington ◽  
F.S. Fay ◽  
K.E. Fogarty ◽  
L. Lifshitz

Advances in digital imaging microscopy and in the synthesis of fluorescent dyes allow the determination of 3D distribution of specific proteins, ions, GNA or DNA in single living cells. Effective use of this technology requires a combination of optical and computer hardware and software for image restoration, feature extraction and computer graphics.The digital imaging microscope consists of a conventional epifluorescence microscope with computer controlled focus, excitation and emission wavelength and duration of excitation. Images are recorded with a cooled (-80°C) CCD. 3D images are obtained as a series of optical sections at .25 - .5 μm intervals.A conventional microscope has substantial blurring along its optical axis. Out of focus contributions to a single optical section cause low contrast and flare; details are poorly resolved along the optical axis. We have developed new computer algorithms for reversing these distortions. These image restoration techniques and scanning confocal microscopes yield significantly better images; the results from the two are comparable.


Author(s):  
S. Mahajan

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.


Author(s):  
John F. Mansfield

The current imaging trend in optical microscopy, scanning electron microscopy (SEM) or transmission electron microscopy (TEM) is to record all data digitally. Most manufacturers currently market digital acquisition systems with their microscope packages. The advantages of digital acquisition include: almost instant viewing of the data as a high-quaity positive image (a major benefit when compared to TEM images recorded onto film, where one must wait until after the microscope session to develop the images); the ability to readily quantify features in the images and measure intensities; and extremely compact storage (removable 5.25” storage devices which now can hold up to several gigabytes of data).The problem for many researchers, however, is that they have perfectly serviceable microscopes that they routinely use that have no digital imaging capabilities with little hope of purchasing a new instrument.


Author(s):  
Xiao Zhang

Polymer microscopy involves multiple imaging techniques. Speed, simplicity, and productivity are key factors in running an industrial polymer microscopy lab. In polymer science, the morphology of a multi-phase blend is often the link between process and properties. The extent to which the researcher can quantify the morphology determines the strength of the link. To aid the polymer microscopist in these tasks, digital imaging systems are becoming more prevalent. Advances in computers, digital imaging hardware and software, and network technologies have made it possible to implement digital imaging systems in industrial microscopy labs.


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