Filament diameter

Fiber Density, kg/m Strength, GPa Modulus, GPa Elongation to break, % Filament diameter, mm... 

Another type of experiment involves a fluid filament being drawn upward against gravity from a reservoir of the fluid (101,213,214), a phenomenon often called the tubeless siphon. The maximum height of the siphon is a measure of the spinnabiUty and extensional viscosity of the fluid. Mote quantitative measures of stress, strain, and strain rate can be determined from the pressure difference and filament diameter. A more recent filament stretching device ia which the specimen is held between two disks that move apart allows measurements ia low viscosity Hquids (215). AH of these methods are limited to spinnable fluids under small total strains and strain rates. High strain rates tend to break the column or filament. 

Textile fibers must be flexible to be useful. The flexural rigidity or stiffness of a fiber is defined as the couple required to bend the fiber to unit curvature (3). The stiffness of an ideal cylindrical rod is proportional to the square of the linear density. Because the linear density is proportional to the square of the diameter, stiffness increases in proportion to the fourth power of the filament diameter. In addition, the shape of the filament cross-section must be considered also. For textile purposes and when flexibiUty is requisite, shear and torsional stresses are relatively minor factors compared to tensile stresses. Techniques for measuring flexural rigidity of fibers have been given in the Hterature (67—73). 

Stress in a Cord. Twisting two or more filaments together to form a cord reduces the overall modulus and strength of the constmction. The degree of the reduction depends on the individual filaments (55). If the lay length is significantly higher than the filament diameter, the stress is... 

As the metal particle size decreases the filament diameter should also decrease. It has been shown that the surface energy of thirmer filaments is larger and hence the filaments are less stable (11,17-18). Also the proportion of the Ni(l 11) planes, which readily cause carbon formation, is lower in smaller Ni particles (19). Therefore, even though the reasons are diverse, in practice the carbon filament formation ceases with catalysts containing smaller Ni particles. Consequently, well dispersed Ni catalysts prepared by deposition precipitation of Ni (average metal particle size below 2-3 nm) were stable for 50 hours on stream and exhibited no filamentous coke [16]. 

Poly[5-(alkylamino)borazines] 7-10 exhibited suitable viscoelastic and thermal stabilities to be extruded in the molten state through the monohole spinneret of a lab-scale melt-spinning apparatus. Thus, an extruded filament (diameter, 200 gm) was drawn with a windup unit, that is, a graphite spool. This provided green fibers with a wide range of diameters (16 =s (f> =s 50 gm Table 2), depending on polymer architecture. 

ISO 11567 1995 Carbon fibre - Determination of filament diameter and cross-sectional area ISO 13002 1998 Carbon fibre - Designation system for filament yarns... 

However, the thermal fluctuations are not the only process that could perturb the propagation of ultrashort laser pulses through the atmosphere. Aerosol particles, like water droplets or dust, can have dimensions of several tens of microns, comparable with the filament diameter they could seriously harm the delicate dynamical balance required to propagate filaments. 

Filaments were visible in the beam profile at the exit of the fog as soon as the transmitted pulse energy was greater than 25 mJ (45 GW), corresponding to 15% transmission (extinction coefficient 0.2 m-1). Hence, filamentation can be transmitted in a fog over a distance comparable with the visibility. In this configuration the particle density was 8.6 x 104 cm 3, so that the mean free path for a 100 pm filament was 0.5 mm Each single filament hits on average 2000 droplets per meter propagation. However, since the droplet radius is about 100 times smaller than the filament diameter, the filaments them-... 

Fig. 24. Filament diameter S. ambofaciens with SEM (a) and epifluroescence microscopy (b) T. reesei with optical microscopy at the beginning (c) and the end (d) of a culture...

Filament diameter, pm 4-7 (carbon fiber), 0.01 (hollow graphite fibrils), 10-13 (pitch-based)... 

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