Real-time measurement of fibers using an HY-differential mobility analyzer with an optical particle counter (KOFAM)
This study investigated the applicability of an HY-differential mobility analyzer with an optical particle counter (HY-DMA/OPC), named as KOFAM, for counting fibrous matters in real time. Fibers separated from particles by the HY-DMA were counted with an OPC. To assess the KOFAM performance, the proposed method and the conventional gold standard phase contrast microscopy (PCM) method were compared in terms of variables such as recovery, relative difference, coefficient of determination, and conformity. The optimal sheath-to-aerosol (outlet) flow ratio of the internal flow in the HY-DMA was determined to be 1.6:1. In terms of recovery of the HY-DMA, the highest recovery was obtained at a voltage of 500 V regardless of which type of asbestos was tested. The recovery rate for serpentine was 45.5% and that for amphibole was 34.9%. The coefficients of determination of serpentine (R2 = 0.89) and amphibole (R2 = 0.87) were highly correlated. With respect to the coefficient of variation (CV), the KOFAM demonstrated superior performance over the M7400AD and F-1 methods and showed almost no difference from the PCM method (KOFAM: 22.5%, M7400AD: 32.4%, F-1: 88.8%, and PCM: 21.9%). There was no statistically significant difference between concentration measurements of the KOFAM and PCM analyses. Accordingly, it was concluded that the KOFAM can be used as a superior alternative to conventional fiber measurement methods. The preliminary results support the use of the KOFAM for constant measurement of airborne asbestos concentrations in real time.
Airborne Fiber Separation by Electrophoresis and Dielectrophoresis: Theory and Design Considerations
The separation of airborne fibers by length and diameter is essential for evaluating inhalation dosimetry, understanding mechanisms of toxicity, and estimating risk to humans from inhaled fibers. Aerodynamic separation of fibrous aerosols depends strongly on fiber diameter and weakly on fiber length. Theoretical calculations show that thin, long fibers can be separated from particles by using differences in their electric mobilities. Fiber separation by length under the influence of electrophoretic forces and dielectrophoretic forces was calculated in a design model for fibers 20, 10, and 3 μm in length and 1 μm in diameter. Electrophoresis describes the motion of a charged object in an electric field, whereas dielectrophoresis describes the motion of neutral matter in a nonuniform electric field. Based on simulation results, 1-μm-diameter fibers having aspect ratios of 20, 10, and 3 can be separated from each other by electrophoresis if the charge ratio on these fibers is 10:5:1, respectively. Twenty-mic...
Inquiring "Tree of Life" at Home: Persian Classic Literature in English Classes.
The recent decades of English Language Teaching (ELT) appear to be particularly concerned with the marginalisation caused by English linguistic, cultural, and academic colonisation and imperialism. Bold footprints of this academic monopoly can be seen in the wide incorporation of abridged or unabridged British and American literary works in foreign language settings. Such literary products are often legitimised as authentic materials authored by native speakers. Inspired by the idea of incorporating non-native literature and translated first language literature into English classes, the authors of this article sought to explore the possibilities of opening spaces for English translations of Persian classic works of literature in English as foreign language classrooms and tracing the language events that unfolded as a result of incorporating such literature. The participants of this two-semester long action research project were non-English major Iranian female university students, majoring in various fields at Alzahra University, Tehran, Iran. The sense of familiarity the students had with such national literary works led to the emergence of language instances lightened by sparks of virtue, vision, life and art.