Fibers sample thickness

Figure 12 Average aspect ratio and volume fraction of TLCP fibers as functions of halved relative sample thickness for four processing conditions.

Figure II. Photographs of 0° epoxy-sized E-glass fiber laminates tested in flexure showing the edge ci the specimen. The failure locus extends through the sample thickness as well as by propagating delaminations along the tensile surface of the specimen.

Figure 35. Mechanical properties of carbon-carbon epoxy-resin hybrid composites, compared with the properties of the composite skeletons before resin impregnation (61,62). The composite skeletons were prepared from Sigrafil HM 3 PAN based fiber, rigidized with a phenolic resin, and densified by four cycles with coal-tar pitch plus sulfur the carbonization temperature was 1000 C. (b) Flexural strength. (c) Interlaminar shear stress, measured with two sample thicknesses.

The angular intensity distribution of X-rays refracted by fibers or spherical pores has been approximated by Hentschel et al. [3]. Quantitative X-ray refraction analysis is implemented at a constant scattering angle of about two minutes of arc and at a fixed wavelength. The refraction value C is proportional to the absolute internal surface density S. With dp denoting the sample thickness the relationship can be given by ... 

A fundamental disadvantage of UV absorbers is the fact that they need a certain absorption depth (sample thickness) for good protection of a plastic. Therefore, the protection of thin section articles, such as films and fibers, with UV absorbers alone is only moderate. 

N. Emami, M. Sjodahl, K.J. Soderhohn, How fiber properties, filler fraction, sample thickness and light source affect hght attenuation in particulate filled resin composites. Dent. Mater. 21 (2005) 721-730. 

This method of analysis is suitable for fiber identification, as well as for characterization of any chemical differences between two fibers of the same class. For instance, acrylic and modacrylic fibers containing copolymers of varying constitution and proportion may be identified. Identification depends on matching the additional bands with those in the IR spectrum of a fiber whose identity is already known. Both the wavelength and intensity differences of bands in each spectrum must be taken into account. Fiber samples may be prepared in the form of a pressed disk, where very finely divided particles of the fiber are uniformly distributed in powdered po-tassiiun bromide. The mixture is pressed into a small disk of about 1 mm thickness in a vacuum die vmder... 

Ultraviolet absorbers were among the first organic stabilizers used. They are colorless compounds that strongly, but selectively absorb ultraviolet radiation and harmlessly dissipate it as heat so that it does not lead to photosensitization. They are also characterized by their very good stability to the absorbed radiation. However, based on the UV absorption mechanism alone, they can only provide limited protection to surface layers and thin samples, for example fibers and films. In accordance with the Beer-Lambert absorption law, the amount of radiation reaching any particular layer diminishes exponentially with the distance from the exposed surface. Thus, the effectiveness of protection via screening of the actinic radiation from the polymer by the UV absorber increases with sample thickness. Protection by UV absorbers is most effective when the additive is concentrated on the surface, such as when it is incorporated in a thin film coextruded over the polymer [75]. 

Most of the principles associated with air sampling using SPME fiber sampling also applied to this sampling method. The thickness of the coating affected the sample time required for the polymer and simulant vapor to come into equilibrium, and thicker polymer layers resulted in more simulant vapor... 

Scaffold Solution concentration (%) Solvent Duration of spinning Sample thickness ( im) Fiber diameter (nm)... 

Several samples were fabricated fiom as-received material to not only deteimine the as-received interfacial shear stress but also as an aid in practicing the sample fabrication process. After initial trials of both machining and fiber push out testing, it was decided to settle on a sample thickness of 0.35 mm. In addition to the as-received material, several samples were made available that had been tested at 1204"C with a hold stress of 165.6 MPa in air for periods of4, 250 and 1508 hours. (The test was either a creep or a 2 hour dwell fatigue test [12].) All samples were machined per the procedure outline above. All samples for this effort were the same thickness to eliminate any issue about residual stresses being a factor due to machining. 

Fiber samples were sputtered and placed in for analyzing using scanning electron microscope. Figure (3, 4) reveals the cross section of raw maize fiber. It has a thick layer of protective material and cellular deposits and also presence of lumen... 

Running Fiber Samples. When running fiber samples in constrained mode, the steel plate on which the fiber is wound up should be as thin as possible. With thick steel plates, excessive baseline sloping will occur. 

Oxidation occurs at the surface. Deeper in the polymer mass, the oxygen supply is limited at a certain level by diffusion, therefore the oxygen uptake is dependent on the sample thickness. In articles with higher surface to volume ratios such as films and fibers, the physical properties deteriorate more rapidly upon oxidation. 

Favorable conditions are present, if either the sample is flat and stays broader than the X-ray beam, or if the material is a fiber with a circular cross-section which is crossed in transverse direction by an oblong X-ray beam. The first mentioned case can easily be realized, if the sample is a tensile bai- of sufficient breadth. In this case, only the sample thickness is changing as a function of load. In the second case, to a first approximation, the intersection between fiber and beam profile yields a truncated cylinder, V, and the cylinder diameter is varying upon mechanical loading of the fiber. 

Knitted continuous glass fibers were used to produce reinforced polyester composites by UV curing associated with vacuum bag resin infusion (VBRI) technique [188]. This approach allowed a maximum thickness of 13 mm. It was noticed that flexural strength and modulus decreased with the increasing sample thickness due to the reduced crossUnking density. 

B. Boundary temperatures 300 to 76 K with nitrogen as the interstitial gas. 0.008-in. fiber glass paper, with one-third material removed by punching holes, wrapped spirally with 76 individual 0.00023-in. aluminum foil shields Inserted. Sample thickness 1.45 in., with 52 shields per inch. 

The analytes from a liquid or from the headspace above a sample are concentrated on a fused silica fiber coated with a polymer film, causing an equilibrium distribution of the analytes to be established between the stationary phase (the microfiber) and the aqueous or gas phase (the sample). Once equilibrium has been established between sample and fiber, the concentrated compounds are thermally desorbed in the injector of a gas chromatograph and transferred to the capillary column (Eig. 1). The parameters to be optimized here are the nature of the fiber coating (fiber polarity) and fiber film thickness, as well as the concentra-... 

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