The Microbiological Deterioration of Rubber Insulation

1953 ◽  
Vol 26 (4) ◽  
pp. 869-883
Author(s):  
John T. Blake ◽  
Donald W. Kitchin ◽  
Orison S. Pratt
Keyword(s):  
Dielectric Strength ◽  
Insulation Resistance ◽  
Great Care ◽  
Moist Air ◽  
Humid Atmosphere ◽  
Buried Cables ◽  
High Insulation ◽  
Pass Through ◽  
In Transit ◽  
Voltage Breakdown

Abstract Experiments on natural rubber and GR-S insulation in various forms have shown them to be inherently vulnerable to fungus attack unless made sufficiently fungitoxic. Stable fungitoxic GR-S compounds have been developed in this work which have invariably maintained normal high insulation resistance during four years in active soil. Thin Neoprene jackets may be permeable to fungi so that underlying insulation should be fungitoxic or inherently stable. A humid atmosphere as in a wet duct may be a dangerous environment. It has been shown that inoculated wire can fail in moist air due to fungus penetration. Parallel electrical tests on wire and culture tests on agar-filled tubes demonstrated that the electrical failures in soil were caused by fungus penetration. It was possible to detect and identify fungus in transit in thick walls of GR-S insulation. Three types of fungi which can pass through rubber insulation and thin Neoprene jackets have been identified, at least by genus. The most prevalent has been Spicaria violacea Abbott. The presence of fungus in insulation lowers the dielectric strength before the filaments have passed completely through the wall. Impending failure can be detected by voltage breakdown tests. Rubber insulation in buried cables must be sufficiently fungitoxic. Great care is required in formulating stable compounds to insure that other required properties are not harmed.

scholarly journals Investigations on X-rays and β-rays by the cloud method. Part 1.—X-rays

1923 ◽  
Vol 104 (724) ◽  
pp. 1-24 ◽  
Keyword(s):  
Water Vapour ◽  
Royal Society ◽  
Convincing Evidence ◽  
Sudden Expansion ◽  
X Rays ◽  
Moist Air ◽  
Saturated State ◽  
Pass Through ◽  
Instrumental Distortion

The method used in these investigations is that which was described in papers communicated to the Royal Society in 1911 and 1912. The ionising rays are made to pass through moist air, or other gas, in which the water-vapour has been brought into the super-saturated state by sudden expansion of the gas. Each ion liberated becomes at once the nucleus for the condensation of a visible droplet of water; the clouds of drops thus formed are immediately photographed. Very sharply defined pictures of the tracks of ionising particles—α- or β-rays—may be obtained in this way. When the conditions are suitably arranged, the effects of diffusion of the ions before their mobility has been destroyed by condensation of water upon them, as well as that of subsequent disturbance of the cloud tracks by convection currents in the gas, are negligible: photographs of the path of the ionising particles, practically free from distortion, are obtained. The almost perfect straightness of the track of a very fast β-particle, when it occurs among a crowd of tracks of slower β-particles, gives very convincing evidence that the complicated forms of the latter are not due to instrumental distortion.

scholarly journals Refraction in exoplanet atmospheres

2018 ◽  
Vol 609 ◽  
pp. A90 ◽  
Author(s):  
D. Alp ◽  
B.-O. Demory
Keyword(s):  
Signal To Noise Ratio ◽  
Light Curves ◽  
Physical Parameters ◽  
Model Parameters ◽  
Transmission Spectroscopy ◽  
Cool Stars ◽  
Red Dwarfs ◽  
Pass Through ◽  
In Transit ◽  
Ppm Level

Context. Refraction deflects photons that pass through atmospheres, which affects transit light curves. Refraction thus provides an avenue to probe physical properties of exoplanet atmospheres and to constrain the presence of clouds and hazes. In addition, an effective surface can be imposed by refraction, thereby limiting the pressure levels probed by transmission spectroscopy. Aims. The main objective of the paper is to model the effects of refraction on photometric light curves for realistic planets and to explore the dependencies on atmospheric physical parameters. We also explore under which circumstances transmission spectra are significantly affected by refraction. Finally, we search for refraction signatures in photometric residuals in Kepler data. Methods. We use the model of Hui & Seager (2002, ApJ, 572, 540) to compute deflection angles and refraction transit light curves, allowing us to explore the parameter space of atmospheric properties. The observational search is performed by stacking large samples of transit light curves from Kepler. Results. We find that out-of-transit refraction shoulders are the most easily observable features, which can reach peak amplitudes of ~10 parts per million (ppm) for planets around Sun-like stars. More typical amplitudes are a few ppm or less for Jovians and at the sub-ppm level for super-Earths. In-transit, ingress, and egress refraction features are challenging to detect because of the short timescales and degeneracies with other transit model parameters. Interestingly, the signal-to-noise ratio of any refraction residuals for planets orbiting Sun-like hosts are expected to be similar for planets orbiting red dwarfs and ultra-cool stars. We also find that the maximum depth probed by transmission spectroscopy is not limited by refraction for weakly lensing planets, but that the incidence of refraction can vary significantly for strongly lensing planets. We find no signs of refraction features in the stacked Kepler light curves, which is in agreement with our model predictions.

scholarly journals Rapid health evaluation in migrant peoples in transit through Darien, Panama: Protocol for a multi-method qualitative and quantitative study

2021 ◽  
Author(s):  
Amanda Gabster ◽  
Monica Jhanigmal ◽  
Jennifer Toller Erausquin ◽  
Jose Antonio Suarez ◽  
Justo Emilio Pinzon-Espinosa ◽  
...  
Keyword(s):  
Health Status ◽  
Well Being ◽  
Border Region ◽  
Healthcare Provision ◽  
Governmental Organizations ◽  
Healthcare Needs ◽  
Non Governmental Organizations ◽  
Drastic Increase ◽  
Pass Through ◽  
In Transit

Abstract Background: The world is currently unprepared to deal with a the drastic increase in global migration. There is an urgent need to develop programs to protect the well being and health of migrant peoples. Increased population movement is already evident throughout the Americas as exemplified by the rising number of migrant peoples that pass through the Darien neotropical moist broadleaf forest along the border region between Panama and Colombia. The transit of migrant peoples through this area has an increase in the last years. In 2021 an average of 9,400 people entered the region per month compared to 2,000-3,500 people monthly in 2019. Along this trail, there is no access to healthcare, food provision, potable water, or housing. To date, much of what is known about health needs and barriers to healthcare within this population is based on journalistic reports and anecdotes. There is a need for a comprehensive approach to assess the healthcare needs migrant peoples in transit. This study aims to describe demographic characteristics, mental and physical health status and needs, and experiences of host communities, and to identify opportunities to improve healthcare provision to migrant peoples in transit in Panama. Study design and methods: This multi-method study will include qualitative (n=70) and quantitative (n=520) components. The qualitative component includes interviews with migrant peoples in transit, national and international non-governmental organizations and agencies based in Panama. The quantitative component is a rapid epidemiological study which includes a questionnaire and four clinical screenings: mental health, sexual and reproductive health, general and tropical medicine, and nutrition. Conclusion: This study will contribute to a better understanding of the health status and needs of migrant peoples in transit through Darien, Panama. Findings will be used to allocate resources and provide targeted healthcare interventions for migrant peoples in transit through Darien, Panama.

Lost in Transit: Product Replacement Bias and Pricing to Market

2012 ◽  
Vol 102 (7) ◽  
pp. 3277-3316 ◽  
Author(s):  
Emi Nakamura ◽  
Jón Steinsson
Keyword(s):  
Price Change ◽  
Price Adjustment ◽  
Price Changes ◽  
Pricing To Market ◽  
Long Run ◽  
Price Indexes ◽  
Product Replacement ◽  
Pass Through ◽  
Exchange Rate Pass Through ◽  
In Transit

In the microdata underlying US trade price indexes, 40 percent of products are replaced before a single price change is observed and 70 percent are replaced after two price changes or fewer. A price index that focuses on price changes for identical items may, therefore, miss an important component of price adjustment occurring at the time of product replacements. We provide a model of this “product replacement bias” and quantify its importance using US data. Accounting for product replacement bias, long-run exchange rate “pass-through” is substantially higher than conventional estimates suggest, and the terms of trade are substantially more volatile. (JEL F14, F31)

scholarly journals V. On the development of lepas fascicularis and the “archizoëa” of cirripedia

1876 ◽  
Vol 166 ◽  
pp. 131-154 ◽  
Keyword(s):  
Great Care ◽  
In Captivity ◽  
The Subject ◽  
Pass Through

Burmeister’s important discovery that in Lepas the larvæ pass through a Nauplius and a Cypris stage was made on the same Lepas which forms the subject of this paper. Burmeister, however, had evidently only a ball of this Lepas , some specimens of which were young in the Cypris stage, which had just settled; while others were dismissing young Nauplii , which, unless great care is taken, die very soon in captivity. He thus missed the intermediate stages, which, however, were at that time much less important, as the first thing that was wanted then was to establish the general outlines of the Cirriped development. The Nauplius of this Lepas has since been seen by Darwin, to whom Hancock showed it, “calling his attention to a proboscidiform projection on the underside of the larva of Lepas fascicularis when just escaped from the egg.” Neither J. v. Thompson’s nor Pagenstecher’s observations refer, as far as I can find out here, to Lepas fascicularis ; and it seems not to have been taken up again as an object for embryological researches until Claus published his paper on the Cypris -like larva (pupa) of the Cirripeds and its metamorphosis into the fixed animal (Marburg, 1869), a paper of which I have unfortunately only an abstract, as given by Nitsche in his embryological report for the year 1872, and by Claus himself in his ‘ Grundzϋge der Zoologie,’ which, however, affords nearly all the information necessary for my purpose. My object is to give an idea of the whole development of one Lepas as accurately as possible, which seems never yet to have been done, as our whole knowledge of the development of this group consists of fragments, collected mostly in the same way in which Burmeister gained his information.

scholarly journals Development of a dielectric ceramic based on diatomite-titania part two: dielectric properties characterization

Cerâmica ◽  
1998 ◽  
Vol 44 (287-288) ◽  
pp. 136-140
Author(s):  
Jamilson Pinto Medeiros ◽  
Elcio Correia de Souza Tavares ◽  
Uilame Umbelino Gomes ◽  
Wilson Acchar
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Temperature Coefficient ◽  
Sintering Temperature ◽  
Dielectric Strength ◽  
Dissipation Factor ◽  
Insulation Resistance ◽  
Dielectric Ceramic ◽  
Dc Voltage ◽  
Titania Content

Dielectric properties of sintered diatomite-titania ceramics are presented. Specific capacitance, dissipation factor, quality factor and dielectric constant were determined as a function of sintering temperature, titania content and frequency; the temperature coefficient of capacitance was measured as a function of frequency. Besides leakage current, the dependence of the insulation resistance and the dielectric strength on the applied dc voltage were studied. The results show that diatomite-titania compositions can be used as an alternative dielectric.

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