An Improved Adaptive Electronic Circulator for Telephone Applications

A previous attempt at realizing an adaptive circulator for telephone applications suffered from limitations due to voice switching problems, resistive part matching only, and some difficulties with adaptive operation for broadband signals. The use of pilot tones enables the circuit to be free from voice switching problems and to accomplish a close impedance match with that of a telephone line. Analysis of the circuit in an adaptive hybrid configuration produces the theoretical bounds on performance. Experimental results display the performance characteristics of the adaptive circuits and various other hybrid circuits on a selection of subscriber lines with a range of terminations.     

A Study on Extraction and Characterization of Keratin Films and Nanofibers from Waste Wool Fiber

ABSTRACT

Fabrication and characterization of keratin films extracted from waste Merino wool fiber using two different methods and three different pH concentrations is the main focus of this study. Also, wool keratin (WK) loaded polymer surfaces were fabricated. The chemical, structural and morphological characteristics of keratin extracted from aqueous solutions were analyzed and compared for both methods. It is concluded that optimized results in this study could contribute in future research studies to select the parameters and methods to extract keratin films from recyclable wool fibers. Also, WK loaded nanofibrous films could be potential in filtration, air purification and tissue engineering.     

Deformation characteristics of age hardened Ti-6Al-4V

A commercial Ti−6Al−4V alloy with an equiaxed grain shape was investigated after solution annealing at 810°C and after aging at 550 and 350°C. Age hardening at both temperatures produced significant increases in Young's modulus and yield strength. Finely dispersed α₂(Ti₃Al) precipitates formed within the α phase upon aging at 550°C, but not when aging at 350°C. However, there is evidence of order, probably of oxygen, in the α grains of specimens which were aged at 350°C. The formation of the ordered Ti₃Al precipitates at 550°C and the occurrence of oxygen ordering at 350°C can account for the increases in Young's modulus and yield strength. since January 1977 with General Electric Co., Lighting Research Division, Nela Park, Cleveland, OH. KANAY GAZIOGLU, formerly with DFVLR, is deceased.     

A study of the modelling and characterisation of compression garments for hypertrophic scarring after burns. Part 2: characterisation of compression garments

Compression therapy is the universally accepted treatment for the management of hypertrophic scarring after severe burns. A review of the type of treatments for burns and type of compression garments commercially available is discussed in Part 1 of this paper (Anand, Kanchi Govarthanam, & Gazioglu, in press). A refined model was also designed to predict the sub-garment pressure more accurately, irrespective of the shape and size of the limb (see Part 1, in press). The thermophysiological properties of the compression garment provide comfort by preserving body temperature and moisture output close to their normal levels. In this study, the dimensional, mechanical and thermophysiological properties of four fabrics procured from different sources were thoroughly studied and compared. The study was aimed at the determination of their suitability to be utilised for the management of hypertrophic scarring. It was established that one of the fabrics investigated possessed superior properties in comparison to the other three fabrics. It was also demonstrated that the characteristics of this particular fabric can be further enhanced for its suitability for use as a compression garment for this specific area of application.     

A study of the modelling and characterisation of compression garments for hypertrophic scarring after burns. Part 1: modelling of compression garments

Skin burns are usually caused by contact with fire, heat, electricity, light, radiation, hazardous chemicals and friction. The degree of the burn is classed based on the extent and depth of the burn. A third-degree burn is classed as a severe burn and compression therapy is universally accepted as the treatment to manage hypertrophic scarring caused after such burns. This paper describes the types of burns and the different types of treatments available and reviews the types of compression garments that are commercially available for the management of hypertrophic scarring after severe burns. The Laplace equation that is used to model a pattern-cutting chart has been refined to predict the sub-garment pressure more accurately, irrespective of the shape and size of the limb. This model’s accuracy was further validated by constructing garments for the arms and legs of a male volunteer and measuring the actual pressures by using a Kikuhime pressure measuring device.     

Development and validation of a HPLC method for the determination of benzo(a)pyrene in human breast milk

A simple analytical procedure was developed for the quantitation of benzo(a)pyrene in human breast milk using solid phase extraction (SPE) combined with high performance liquid chromatography. Before the chromatographic process, SPE, including C18 functional groups in silicagel cartridges, was conducted for sample preparation. A C18 column (100×4.6 mm id, 3 μm particle size) was used with acetonitrile:water (80:20) as the mobile phase at a flow rate 1mL/min at 30°C. Fluorimetric detection was performed for excitation and emission at 290 and 406 nm, respectively. It was observed that the calibration curve was linear over the range of 0.5–80 ng/mL. The limit of detection and limit of quantitation were found to be 0.5 and 1.07 ng/mL, respectively. Intraday and interday relative standard deviation values were less than 5.15%. Moreover, the newly developed method provides a fast, simple, cost effective, and sensitive assay to detect an important carcinogen substance, benzo(a)pyrene, in human breast milk.