22—FACTORS AFFECTING THE THICKNESS AND COMPRESSIBILITY OF WORSTED-SPUN YARNS

In this paper, the impact of short fiber content, yarn count and yarn delivery speed on the structure and properties of fine count cotton vortex yarns were investigated. The factors affecting the fine count yarn spinning on a vortex spinning system were determined on the basis of yarn structure and properties by using the linear regression technique. Moreover, the spinning limits of combed cotton vortex spun yarns were investigated. The results of the experiments revealed that the short fiber content in the cotton sliver is an important parameter in spinning fine count vortex spun yarns. The lower short fiber content in the sliver allows finer counts to be spun in the vortex spinning system. It was also observed that yarn delivery speed influences the yarn structure, and hence the yarn properties significantly, since it determines the residence time of the fibers in the yarn formation zone, and also affects the fiber control due to the air flow caused by the surface speed of the delivery rollers. In addition, the structure and properties of vortex spun yarns change significantly with regard to yarn count.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078614 ◽

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.

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Factors affecting microstructural scale in liquid crystalline polymers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100174230 ◽

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.

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Factors affecting dentist participation in a state Medicaid program

Journal of Dental Education ◽

10.1002/j.0022-0337.1990.54.11.tb02476.x ◽

1990 ◽

Vol 54 (11) ◽

pp. 638-643 ◽

Cited By ~ 20

Author(s):

PC Damiano ◽

ER Brown ◽

JD Johnson ◽

JP Scheetz

Keyword(s):

Medicaid Program ◽

Factors Affecting

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