Johns Manville (Slovakia)

Antibiotics in the environment represent a significant pollutant with a great impact on the biota. With the increasing use of these substances, the resistance against them notably grows. The phototrophs, as the key part of microbial communities, often have different responses to antibiotics. Some species could be inhibited; on the other hand, some species show the ability to use antibiotics as a source of necessary nutrients. In our study, we investigated the impact of streptomycin, gentamicin, and sulfacetamide on six strains of cyanobacteria commonly present in water sources. The growth inhibitory effect of the studied antibiotics was measured in sterile 96-well microtiter plates, which contained different concentrations of antibiotics (1024 – 0.5 µg/mL) during 7 days at 23 °C and with 24h illumination (light intensity 48,6 µmol. foton m-2 s-1). Then the results were statistically evaluated, and growth curves were designed for each studied strain. The minimum inhibitory concentration (MIC) of the investigated antibiotics was evaluated using probit analysis. The potential effect of antibiotics on tested strains morphology was also studied. The results show that the antibiotics have an inhibitory effect at higher concentrations (891.76 μg/mL to 1495.10 μg/mL). The highest values of MIC were estimated for Synechocystis sp. (PCC 6803) and Cephalotrix sp. (KL 18). The stimulation of growth was observed in the strains Synechocystis (PCC 6803) and Cephalothrix (KL 18). The most sensitive strains to selected antibiotics were Chlorogleopsis fritschii (CCALA 1005), Lyngbya martensiana (CCALA 930), and Geitlerinema acuminatum (CCALA 141). Strain Cyanobium sp. (LH14) was sensitive to streptomycin sulphate and gentamicin sulphate, but sulfacetamide stimulated its growth. The visible morphological changes were caused by streptomycin in Chlorogloeopsis fritschii (CCALA 1005). After five days of cultivation the bleached cells were present in the cultures of this strain.

The high vitamin A activity of the petroleum ether extract of the annatto seed has been confirmed. It ranges from 1,000 to 2,000 international units of vitamin A per gram of extract. It was found that a standard mixture of 3-percent acetone in petroleum ether did not remove any vitamin A-active material from a magnesium oxide-hyflo supercel column, on which a petroleum ether extract of annatto had been chromatographed. The only solvent among those tried, that effectively removed the material which was left absorbed on the column after elution with acetone-petroleum ether was methanol. The methanol extract exhibited a biological activity of about the same order of magnitude as the original petroleum ether extract, that is, 1,000 to 2,000 international units of vitamin A.

Abstract The purpose of the book is to help practicing engineers learn to y Taguchi experimental design techniques through the use of ry, step-by-step applications of concepts, and an introduction he Qualitek-4. software. Common manufacturing floor language sed to make the book understandable by technicians, engineers, managers. Equations are reduced in the text to further litate understanding. The book accomplishes this task and is a readable book. The reader, however, should be alert for occasional graphical errors in the text and calculations, which are always obvious.

Journal of Vinyl TechnologyVolume 3, Issue 1 p. 56-76 Article PVC processing Glenn Prejean, Glenn Prejean Moderator Dow Chemical U.S.A.Search for more papers by this authorA. S. (Bud) Pazur, A. S. (Bud) Pazur Speaker Diamond ShamrockSearch for more papers by this authorM. Fred Marx, M. Fred Marx Speaker Western ElectricSearch for more papers by this authorPeter Vanderpool, Peter Vanderpool Speaker Ethyl CorporationSearch for more papers by this authorGeorge Pullman, George Pullman Speaker Hooker ChemicalSearch for more papers by this authorHal Stiskin, Hal Stiskin Panel Member R & G Sloane Mfg. Co.Search for more papers by this authorDr. A. William Coaker, Dr. A. William Coaker Panel Member Tenneco ChemicalsSearch for more papers by this authorWarren Mauter, Warren Mauter Panel Member Johns-ManvilleSearch for more papers by this author Glenn Prejean, Glenn Prejean Moderator Dow Chemical U.S.A.Search for more papers by this authorA. S. (Bud) Pazur, A. S. (Bud) Pazur Speaker Diamond ShamrockSearch for more papers by this authorM. Fred Marx, M. Fred Marx Speaker Western ElectricSearch for more papers by this authorPeter Vanderpool, Peter Vanderpool Speaker Ethyl CorporationSearch for more papers by this authorGeorge Pullman, George Pullman Speaker Hooker ChemicalSearch for more papers by this authorHal Stiskin, Hal Stiskin Panel Member R & G Sloane Mfg. Co.Search for more papers by this authorDr. A. William Coaker, Dr. A. William Coaker Panel Member Tenneco ChemicalsSearch for more papers by this authorWarren Mauter, Warren Mauter Panel Member Johns-ManvilleSearch for more papers by this author First published: March 1981 https://doi.org/10.1002/vnl.730030105Citations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume3, Issue1March 1981Pages 56-76 RelatedInformation

A cryogenic thermal-conductivity heat-flow-meter apparatus (cryogenic heat meter), a modification of the apparatus described in a previous ASTM publication, is described. This apparatus enables a rapid determination of thermal conductivity of felt, powder, and block materials to be made at cryogenic temperatures and at atmospheric pressure. The apparatus is particularly suitable for screening a large number of specimens, for obtaining product development information, and for quality control testing. The correlation among results obtained with the cryogenic heat meter and the Wilkes calorimeter and a National Bureau of Standards' cryogenic calorimeter is excellent. Correlation of cryogenic heat-meter results with those obtained at higher temperatures on a heat-flow-meter apparatus and a guarded-hot-plate apparatus is good. A range of temperatures can be applied to the test specimen. Therefore, use conditions can be simulated, if desired.

Abstract Frictional vibrations, such as stick-slip motion and automobile-brake squeal, which occur when two solid bodies are rubbed together, are analyzed mathematically and observed experimentally. The conditions studied are slow uniform motion and relatively rapid simple harmonic motion of brake lining over a cast-iron base. The equations of motion show and the observations confirm that frictional vibrations are caused primarily by an inverse variation of coefficient of friction with sliding velocity, but their form and occurrence are greatly dependent upon the dynamical constants of the mechanical system. With a constant coefficient of friction, the vibration initiated whenever sliding begins is rapidly damped out, not by the friction but by the “natural” damping of all mechanical systems. The coefficient of friction of most brake linings and other organic materials was essentially invariant with velocity, except that the static coefficient was usually greater than the sliding coefficient. Most such materials usually showed a small decrease in coefficient with increasing temperature. The persistent vibrations resulting from the excess static friction were reduced or eliminated by treating the rubbing surfaces with polar organic compounds which produced a rising friction characteristic.

Abstract Improvement in comfort may be realized by lowering the noise level to which the passenger is subjected. The author outlines the scientific approach to the noise problem, giving the analytical formulas essential to its study. These principles are then applied to railroad transportation problems.

Abstract Economic thickness of an insulation is defined as that thickness yielding the smallest sum of cost of heat loss and fixed cost of insulation. The difficulties in determining the economic thickness for intermittent operation are reviewed. By means of the electrical-analogy method, curves have been developed which permit the ready determination of the heat losses in intermittent operation for any temperature, any single-material wall, any intermittency, any length of period, and any film conductance. These curves permit the determination of the economic thickness for intermittent operation. The application of the curves is illustrated by an example. The influence of intermittency on the economic thickness is discussed for one specific case. The limitations of the method and prospect of obtaining results avoiding the limitations are considered.