Nonwoven fabrics are ideal materials for use as acoustical insulation products because they have high total surface. The surface area of the fabric is directly related to the denier and crosssectional shape of the fibers in the fabric. Smaller deniers yield more fibers per unit weight of the material, higher total fiber surface area and greater possibilities for a sound wave to interact with the fibers in the structure. Another important parameter is the packing density of the fibers in the nonwoven material. More fibers per unit volume at the same fabric thickness yield greater possibilities for sound waves to interact with the fibers. Fabric density also affects the geometry and the volume of the voids in the fabric structure. Acoustical properties of fabric materials are measured by one of two methods: the impedance tube method (ASTM C 384-98) and the acoustical chamber method. The impedance tube method uses very small test samples. Large reverberation rooms and large test samples are used for the acoustic chamber method. A direct comparative acoustical properties measurement device has been developed and fabricated at Clemson University School of Materials Science and Engineering. This paper provides a description of the measurement devices and acoustical measurement data for needlepunched nonwoven fabrics made from three different polyester fiber shapes and two denier levels.

Acoustical insulation and absorption properties of nonwoven fabrics depend on fiber geometry and fiber arrangement within the fabric structure. The different structures of the fibers result in different total surface areas of nonwoven fabrics. Nonwoven fabrics such as vertically lapped fabrics are ideal materials for use as acoustical insulation products, because they have high total surface. Vertically lapped nonwoven technology consists of carding, perpendicular layering of the carded webs, and through-air bonding using synthetic binder fibers. The surface area of the fabric is directly related to the denier and cross-sectional shape of the fibers in the fabric. Smaller deniers yield more fibers per unit weight of the material, higher total fiber surface area, and greater possibilities for a sound wave to interact with the fibers in the fabric structure. The research in the literature uses two methods for measuring acoustical properties of fabric materials: the impedance tube and reverberation room method. Small test samples are in the impedance tube method and sound absorption coefficient is determined at each frequency. Large reverberation rooms and large test samples are used for the reverberation room method. A direct comparative acoustical properties measurement device that was designed and fabricated at Clemson University School of Materials Science & Engineering was used to measure acoustical insulation in this research. This paper provides a description of the measurement devices and acoustical measurement data for vertically lapped nonwoven fabrics made from three different polyester fiber shape and two denier levels.

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Additional index words. skullcap, baicalin, baicalein, flavonoid, polyester fiber, medicinal plant, wogonin Abstract. Three Scutellaria species (Scutellaria lateriflora, S. costaricana, and S. baicalensis) were grown in different in vitro physical environments: agar, liquid culture, and liquid culture with fiber-supported paper (with initial media volumes of 20 mL and 30 mL). During an 8-week time course, tissue growth was assessed for each species by fresh weight (FW), dry weight (DW), percent DW, and multiplication ratio. Water use and hyperhydricity were also compared. Scutellaria lateriflora plantlets grown in liquid were hyperhydric despite the greatest accumulation of dry mass, but multiplication diminished with time as plants became hyperhydric. In contrast, S. costaricana and S. baicalensis plantlets had higher FW and DW on agar. With all Scutellaria species tested, plantlets grown on agar or fiber-supported paper were not hyperhydric, and fiber-supported paper with 20 mL initial volume yielded plants with the greatest percent DW. The lowered hyperhydricity was related to reduced water uptake. The flavonoids baicalin, baicalein, and wogonin were quantified in plants grown on fiber-supported paper culture. The baicalin concentrations in in vitro cultured S. lateriflora shoots was comparable to those of field-grown plants. The in vitro method presented a unique opportunity to enhance baicalein content and produce wogonin-rich roots. S. costaricana plantlets in vitro showed high levels of the three flavonoids compared with S. baicalensis and S. lateriflora. Growing non-hyperhydric tissues on fiber-supported paper, in vitro, allowed the clonal propagation of Scutellaria species with increased flavonoid content to proceed in a simple, controlled environment.

A PVDF polymer has very good strength, toughness and piezoelectric properties and is nowadays used as the film in strain sensors, mechanical actuators, energy harvesters and artificial muscles. Furthermore, PVDF polymer is used as the fiber in hollow fiber membranes for filtration applications. This article introduces the manufacturing of solid PVDF fibers by a wet spinning process and investigates the effects of the process parameters (i.e. drawing temperatures and drawing ratios on the first and second bath) on macroscopic properties (i.e. fiber linear density, fiber shape, density, porosity, strength and elongation) of solid wet-spun PVDF fibers. Increasing the drawing ratio at the first region of the wet spinning of the PVDF fiber increases the porosity. However, if the drawing is performed at the second drawing bath, the porosity of the PVDF fibers remains almost same. The slopes of the strength vs. drawing ratio and elongation vs. drawing ratio curves increase if the drawing is performed at the second drawing bath. The drawing ratio at the first bath does not affect the tensile properties of fibers, such as tensile strength and elongation. Information about the relationships between the process parameters and macro properties of PVDF fibers is very important so that PVDF fibers with the required properties can be produced with a wet spinning process by setting the correct process parameters.