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Advanced technical textile products
Published in T. Matsuo, Textile Progress, 2019
For the long-distance transmission, single-mode quartz fiber whose core diameter is about 10 µm is usually used. For middle-distance transmission, quartz fiber whose core diameter is 200 µm is usually used. Plastic optical fiber is used for short-distance transmission. Its main end uses are expected to be the LANs of automobiles, buildings such as offices, hospitals, universities, and apartments.
Thermoanalytical Instrumentation and Applications
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Kenneth S. Alexander, Alan T. Riga, Peter J. Haines
In the helical spring balance, Hooke’s law is utilized to convert an elongation or contraction of the spring into a record of mass change. The spring material is important. Usually, a quartz fiber is employed, as this avoids anomalous results associated with temperature change and fatigue problems. The method has been used extensively in adsorption studies of gases and vapors on solids (Gregg and Sing, 1982). A balance of this kind was used by Loners (Loners, 1952) for the study of metal oxidation. The Aminco Thermo-Grav unit employed a precision spring that could be selected to give the desired sensitivity and damped magnetically or with a fluid dashpot to reduce oscillations (Daniels, 1973). The cantilevered beam has one end fixed, with the other end, on which the sample is placed, free to undergo deflections. The deflection can be translated into mass loss by methods utilized for beam type balances. In the torsion-wire balance the beam is attached to a taut wire, which acts as the fulcrum. Deflections are proportional to changes in mass and the torsional characteristics of the wire. In all these deflection-type balances various techniques may be used for the measurement and recording of the deflection which, by calibration, can be converted to mass change. An optical lever arrangement can be used, involving measuring the deflections by means of a light beam reflected from a mirror mounted on the balance beam. These deflections can be recorded photographically or measured electronically by means of a shutter attached to the balance beam, to intercept a light beam impinging on a phototube. The light intensity is a measure of the beam deflection and is thus related to mass change. A further method of measuring deflection employs a linear variable differential transformer (LVDT) using an armature freely suspended from the balance beam into the coil of a differential transformer. Strain gauges can also be used to measure beam deflections.
Experimental study of droplet combustion and diesel engine characteristics for Azolla biodiesel
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Saravanan Chidambaram Ganapathy, Thiruvenkatachari Seshadri, Sasikala Jayaraman, Vallinayagam Raman, Vikneswaran Malaiperumal, Manoj Babu Arondoss, Femilda Josephin Joseph Shobana Bai, Edwin Geo Varuvel
The droplet combustion experiments were conducted under ambient temperature and pressure conditions under gravity. Figure 3 shows a top view of the schematic of the droplet combustion experimental setup. The droplet was suspended in a horizontal quartz fiber tube of 500 μm in diameter. The primary concern with fiber tubes is that their thermal conductivity affects the droplet burning process by increasing the internal droplet heating thru heat conduction. This in turn increases the droplet evaporation rate. In addition, the average droplet vaporization rate rises linearly with the cross-sectional area of the fiber. Hence, some of the previous studies (Chandra et al. 2020; Yang and Wu 2017) used microfiber tubes of diameter less than 100 microns to neglect this effect because they exhibit very thermal conductivity (Hoxie, Schoo, and Braden 2014). However, in the present study, the consequence of such an effect may not be negligible. Therefore, this study used the same type of fiber for all three test fuels, believing that the conclusions arrived are not biased. For example, during droplet burning, any additional heat transfer to the liquid through heat conduction from the fiber is expected to be nearly the same in all the cases, such that the variation in combustion characteristics that this study brings out is attributed mainly to the type of fuels used.
On the techniques and standards of particulate matter sampling
Published in Journal of the Air & Waste Management Association, 2022
Prashant Patel, Shankar G. Aggarwal
It is essential to understand the basic structure/setup laid by different nations’ standards and their technical aspects and limitations under certain conditions. Figure 1 describes the basic format of PM measurement and sampling techniques as per NAAQS that is commonly followed in different nations. First, the basic setup is selected based on sampling flow rate, then tagged as LVS or HVS. Most of the PM2.5 sampling is carried out at a low flow rate, while for TSP, SPM, and PM10 sampling flow, much flexibility is given, where LVS, HVS, or MVS (mid-volume sampler) can be used. The basic arrangement is as follows, first the aerosol inlet (PM head) is positioned from where the aerosol is drawn inside the sampler. After that, the inline particle separator segregates the PM into class, i.e. SPM, PM10, and PM2.5. These particle separators are generally called impactors or cyclone separators. These separators allow only the lower fraction of the PM class to move to the filter where it gets deposited or collected. These filters are commonly made up of glass fiber, polytetrafluoroethylene (PTFE), quartz fiber, cellulose ester, etc. The type of filters used varies based on the purpose of sampling.
Development and evaluation of a mobile laboratory for collecting short-duration near-road fine and coarse ambient particle and road dust samples
Published in Journal of the Air & Waste Management Association, 2021
Marco Martins, Joy Lawrence, Stephen Ferguson, Jack M. Wolfson, Petros Koutrakis
After the SSI, the flow was split in half, using a custom-designed Y-divider with a 15° angle to minimize particle losses. From one channel an isokinetic probe was used to collect PM10 on a 47 mm filter at 15 LPM. Another isokinetic probe on the other channel was used with a conventional 30 LPM impactor (with an impaction stage to remove particles above 2.5 µm) to collect PM2.5 at 30 LPM. PM samples were collected on Teflon/or quartz fiber filters. Two photos and a schematic drawing of the RDA are shown in Figures 3a, b, and 4, respectively. For the validation tests, duplicate Teflon filters were used. A five-minute sampling time was sufficient to achieve quantitative filter loadings for gravimetric and trace elemental analysis, and the area vacuumed was approximately 12 m2 or 129 ft2.