Sample records for ebonite
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NASA Technical Reports Server (NTRS)
1985-01-01
Exactatron, an accurate weighing and spotting system in bowling ball manufacture, was developed by Ebonite International engineers with the assistance of a NASA computer search which identified Jet Propulsion Laboratory (JPL) technology. The JPL research concerned a means of determining the center of an object's mass, and an apparatus for measuring liquid viscosity, enabling Ebonite to identify the exact spotting of the drilling point for top weighting.
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An Instrumental Method to Identify Electric Charge Types with a Simple Device
ERIC Educational Resources Information Center
Isik, Hakan
2015-01-01
In this study, an easy and enjoyable activity to determine the type of electric charge is presented, using a readymade electronic test screw. A four-way usage of the tester is explained with an electroscope. In the activity, ebonite and glass rods are negatively and positively charged by rubbing with paper sheets, respectively.
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NASA Astrophysics Data System (ADS)
Babaeva, N. A.; Vas'kovskiĭ, Yu M.; Rovinskiĭ, R. E.; Ryabinkina, V. A.
1991-09-01
Measurements were made of components of the energy balance in the interaction of pulsed CO2 laser radiation with Dural, glass, quartz, ebonite, and Plexiglas in air at atmospheric pressure. At laser energy densities between 1 and 20 J/cm2 and in the spectral range 0.2-7 μm, the re-emission of radiation by the laser plasma was found to be less than 1 %. At energy densities exceeding 10 J/cm2, up to 90% of the laser energy failed to reach the irradiated surface.
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NASA Astrophysics Data System (ADS)
Min'ko, L. Ya; Chumakou, A. N.; Bosak, N. A.
1990-11-01
A study was made of the interaction of a series of periodic laser (λ = 1.06 μm) pulses with a number of materials (aluminum, copper, graphite, ebonite) in air at laser radiation power densities q = 107-109 W/cm2 and repetition frequencies f<=50 kHz. The radiation was concentrated in spots of ~ 10 - 2 cm2 area. Efficient formation of plasma as a result of laser erosion (q > 2 × 108 W/cm2, f>=5 kHz) was observed. A screening layer of an air plasma created by the first pulse of the series was expelled from the interaction zone and this was followed by erosion plasma formation under conditions of slight screening of the target during the action of the subsequent laser pulses.
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Tonpheng, Bounphanh; Yu, Junchun; Andersson, Ove
2011-09-07
The thermal conductivity κ, heat capacity per unit volume ρc(p) and glass transition behaviour under pressure have been established for medium and high vinyl content polybutadiene PB with molecular weights 2600 and 100,000 and their highly cross-linked (ebonite) states obtained purely by high-pressure high-temperature treatments. Cross-linking eliminates the glass transitions and increases κ by as much as 50% at 295 K and 1 atm, and decreases ρc(p) to a limiting level close to that of the glassy state of PB, which is reached before the ultimate cross-link density is achieved. The pressure and temperature behaviours of κ are strongly changed by cross-links, which increases the effect of temperature but decreases the effect of pressure. We attribute these changes to a cross-linked induced permanent densification and consequential increase of phonon velocity simultaneously as conduction along polymer chains is disrupted. The glass transition temperatures for a time scale of 1 s are described to within 0.5 K by: T(g)(p) = 202.5 (1 + 2.94 p)(0.286) and T(g)(p) = 272.3 (1 + 2.57 p)(0.233) (p in GPa and T in K) up to 1 GPa, for PB2600 and PB100000, respectively, and can be estimated for medium and high vinyl content PBs with molecular weights in between by a constant, pressure independent, shift in temperature. This journal is © the Owner Societies 2011
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Moriura, Nobuyuki; Matsuda, Yoshinori; Oichi, Wataru; Nakashima, Shinya; Hirai, Tatsuo; Sameshima, Takeshi; Nonomura, Teruo; Kakutani, Koji; Kusakari, Shin-Ichi; Higashi, Katsuhide; Toyoda, Hideyoshi
2006-01-01
Conidial formation and secession by living conidiophores of Blumeria graminis f. sp. hordei on barley leaves were consecutively monitored using a high-fidelity digital microscopic technique combined with electrostatic micromanipulation to trap the released conidia. Conidial chains formed on conidiophores through a series of septum-mediated division and growth of generative cells. Apical conidial cells on the conidiophores were abstricted after the conidial chains developed ten conidial cells. The conidia were electrically conductive, and a positive charge was induced in the cells by a negatively polarized insulator probe (ebonite). The electrostatic force between the conidia and the insulator was used to attract the abstricted conidia from the conidiophores on leaves. This conidium movement from the targeted conidiophore to the rod was directly viewed under the digital microscope, and the length of the interval between conidial septation and secession, the total number of the conidia produced by a single conidiophore, and the modes of conidiogenesis were clarified. During the stage of conidial secession, the generative cells pushed new conidial cells upwards by repeated division and growth. The successive release of two apical conidia was synchronized with the successive septation and growth of a generative cell. The release ceased after 4-5 conidia were released without division and growth of the generative cell. Thus, the life of an individual conidiophore (from the erection of the conidiophore to the release of the final conidium) was shown to be 107 h and to produce an average of 33 conidia. To our knowledge, this is the first report on the direct estimation of life-long conidial production by a powdery mildew on host leaves.
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Dose assessment to workers in a dicalcium phosphate production plant.
Mulas, D; Garcia-Orellana, J; Casacuberta, N; Hierro, A; Moreno, V; Masqué, P
2016-12-01
The production of dicalcium phosphate (DCP) uses phosphate rock (PR) as a raw material. Sedimentary phosphate rocks are enriched with relevant concentrations of natural radionuclides from the 238 U decay chain (around 10 3 Bq·kg -1 ), leading to the need of controlling potential exposures to radiation of workers and members of the public in accordance with IAEA safety standards. Indeed, phosphate industries are classified as Naturally Occurring Radioactive Material (NORM) industries. Thus, the aim of this work is to assess the radiological risk of the workers in a DCP production plant located in the Iberian Peninsula (South-West Europe), which digests PR with hydrochloric acid. In the present study 238 U, 230 Th, 222 Rn, 210 Pb and 210 Po concentrations in aerosols (indoor and outdoor areas) are reported. Aerosols showed concentrations between 0.42-92 mBq·m -3 for 238 U, 0.24-33 mBq·m -3 for 230 Th, 0.67-147 mBq·m -3 for 210 Pb and 0.09-34 mBq·m -3 for 210 Po. Long-term exposure (four months) of passive 222 Rn detectors provided concentrations that ranged from detection limit (< DL) to 121 Bq·m -3 in outdoor areas and from < DL to 211 Bq·m -3 in indoor areas, similar to concentrations obtained from short-term measurements with active detectors from < DL to 117 Bq·m -3 in outdoor areas and from < DL to 318 Bq·m -3 in indoor places. 226 Ra accumulation in ebonite and pipe scales were the most important contributions to the ambient dose equivalent H*(10), resulting in 0.07 (background)-27 μSv·h -1 with a median value of 1.1 μSv·h -1 . Average 222 Rn air concentrations were lower than the 300 Bq·m -3 limit and therefore, according to European Directive 2013/59/EURATOM, 222 Rn concentration is excluded from the worker operational annual effective dose. Thus, considering the inhalation of aerosols and the external dose sources, the total effective dose determined for plant operators was 0.37 mSv·y -1 . Copyright © 2016 Elsevier Ltd. All rights reserved.