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[en] The regularities of the formation of carbon adsorbent from charcoal coke under the influences of ionizing radiation and heat have been studied. In both stages of obtaining active adsorbent, i.e. in coking and activation processes, the stimulating effect of radiation is observed. Thus, a temperature decline by 200-450 degrees Celsius compared with thermal processes, and an increase in sorption capacity and mechanical strength of the obtained product were observed. The sorption capacity of the activated carbon by radiation-thermal methods 2,3 times more the adsorbent produced by thermal methods. As a result of polycondensation processes occurring under the effect of radiation on the carbon material, the mechanical strength of the product increases by 11.3%. The mechanism of the investigated processes is discussed, and it is shown that the occurring processes are due to the high penetrating ability and chemical effects of ionizing radiation. The technico-economical evaluation has been conducted and it has been found that using the electron accelerator having the beam power of 5,0 kW, allows producing 28,800 tons' highquality carbon adsorbents per year.
[en] The process claimed includes the steps of transferring radon gas produced by a sample to a charcoal trap, cooled to a temperature whereby the radon is absorbed by the charcoal, heating the charcoal trap to a sufficient temperature to release the radon, and transferring the radon to a counting device where the gas particles are counted
[en] Radon measurements, as do any measurements, include errors in their readings. The relative values of such errors depend principally on the measurement methods used, the radon concentration to be measured and the duration of the measurements. Typical exposure times for radon surveys using passive detectors [nuclear track detectors, activated charcoal, electrostatic (E-perm), etc.)] may extend from a few days to months, whereas, in the case of screening methods utilising active radon monitors (AlphaGUARD, RAD7, EQF, etc.), the measurements may be completed quickly within a few hours to a few days. Thus, the latter may have relatively large error values, which affect the measurement accuracy significantly compared with the former measurements made over long time periods. The method presented in this paper examines the uncertainty of a short term radon measurement as an estimate of the long-term mean and suggests a minimum measurement time to achieve a given margin of uncertainty of that estimate. (authors)
[en] A method for radioimmunoassay of serum progesterone is described which does not require extraction. A chromatographic step is not necessary because of the high specifity of the antibody. The intraassay coefficient of variation was 6.1 % and the interassay coefficient of variation was 8.4%. The detection limit was 10 pg/tube that means 1 ng/ml serum. The test on parallelity was correct up to 10 μl serum. The results compared with results of a radioimmunoassay with extraction were identical. High concentrations of hormone in serum and an antibody of high specifity are required for the direct radioimmunoassay of steroids. Using the dextran-charcoal-system for separation of free from antibody-bound steroid the relationship of the quantity of serum to the quantity of charcoal is of great importance. These problems are discussed. (orig.)
[de]Es wird eine radioimmunologische Methode fuer die Messung von Progesteron im Serum beschrieben, die ein direktes Einsetzen des Serums ohne vorherige Extraktion des Steroids erlaubt. Ein chromatographischer Trennungsschritt entfaellt auf Grund der hohen Spezifitaet des Antikoerpers. Der Intraassay-Variationskoeffizient betrug 6,1%, der Interassay-Variationskoeffizient 8,4%. Die Wiederfindungsgrenze lag bei 10 pg/Ansatz bzw. 1ng/ml Serum. Die Kontrolle auf Parallelitaet ergab ein korrektes Verhalten bis 10μl Serum. Ermittelte Serumwerte wurden mit einem Extraktionsradioimmunoassay verglichen und ergaben identische Ergebnisse. Die Voraussetzungen fuer einen direkten Steroidradioimmunoassay sind eine hohe Serumkonzentration des Hormons und ein hochspezifischer Antikoerper. Bei Verwendung des Dextran-Aktivkohlesystems zur Trennung von freiem und gebundenem Steroid ist das Verhaeltnis von eingesetzter Serummenge zur Aktivkohlemenge von entscheidender Bedeutung. Diese Problematik wird diskutiert. (orig.)
[en] Biochars are anthropogenic carbonaceous sorbent and their influences on the sorption of environmental contaminants need to be characterized. Here we evaluated the effect of Pinus radiata derived biochars on soil sorption and desorption of phenanthrene. Two biochars separately produced at 350 oC and 700 oC and three soils were tested. Biochar amendment generally enhanced the soil sorption of phenanthrene. The biochar produced at 700 oC generally showed a greater ability at enhancing a soil's sorption ability than that prepared at 350 oC. The single-step desorption measurement showed an apparent hysteresis in biochar-amended soils. After 28 d equilibration, the sorptive capacity of biochar-amended soil (with an organic carbon content of 0.16%) significantly decreased. This study clearly suggested that biochar application enhanced soil sorption of hydrophobic organic compounds, but the magnitude of enhancement depended on the preparation of biochars, the indigenous soil organic carbon levels, and the contact time between soil and biochar. - Pinus radiata derived biochars influence soil sorption and desorption of phenanthrene.
[en] The first step in radon concentration measurement is an inexpensive screening measurement to determine whether a house has a potential for causing high exposures to its occupants. If the obtained result is bellow the screening level (200 Bq/m3), follow-up measurements are probably not needed. Short-term measurement of radon in homes and schools with charcoal canister is easy to perform and it has to be based on standardized protocols to ensure accurate and consistent measurements. The method of measurement is based on radon adsorption on coal and measurement of gamma radiation of radon daughters. Charcoal canisters were placed at distance of 1 m from the floor and the walls. Upon closing the canisters, the measurement was carried out after achieving the equilibrium between radon and its daughters (at least 3 hours) using NaI or HPGe detector. Canisters used for the measurement were calibrated by 226Ra standard in the same geometry. Systematic survey of radon concentration in dwellings was performed in Belgrade in 2016. The charcoal canisters were exposed in the homes, kindergartens and schools. The data resulting from this radon survey merely show a preliminary picture of indoor radon concentration, but the results are in agreement with the previous work and we can conclude that situation is satisfactory. (author).
[en] Rice husk and saw dust are attempted as alternate adsorbents to charcoal for the removal of reactive dye, namely remazol brilliant blue from aqueous media. The adsorption of remazol brilliant blue has been studied onto rice husk, saw dust and charcoal at different shaking times, adsorbent dosage, temperatures and pH values and their results are compared. The adsorption data was fitted to Freundlich and Langmuir isotherms and corresponding adsorption parameters for each were calculated. Pseudo first and second order kinetic models were used to calculate the amount adsorbed at equilibrium (qe). The calculated values of qe for pseudo-second order equation were found to be in good agreement with those of experimental values. The monolayer capacity (Vm) for rice husk (0.699 mg g/sup -1/) is greater than that for charcoal (0.074 mg g/sup -1/) and saw dust (0.114 mg g/sup -1/). It is concluded that rice husk is found better adsorbent for the removal of remazol brilliant blue as compared to charcoal and saw dust. (author)
[en] Radon has lately been very closely studied because it is popularly believed that large inhalation of it can cause cancer. Hence radon measurement has assumed great prominence in many institutions, especially in developed countries. This report presents a simple and practical method of measurement of Radon gas by a passive detector using activated charcoal. This method was pioneered by Environmental Measurement Laboratory (EML), New York, which has a very good Radon calibration facility. (author)
[en] The ITER sorption cryopumps will see different regeneration stages, one of them being a high temperature regeneration step to release quantitatively all water-like substances with strong sorption bonding forces to the activated charcoal sorbent used in the pumps. Tests have been made in the TIMO test bed at Forschungszentrum Karlsruhe with a model of the ITER torus cryopump to investigate the conditions needed to meet this requirement. It is shown that 470 K is a 'one for all' temperature level believed to regenerate from all species expected to be seen from the ITER cryopumps, including hydrocarbons. For only water regeneration, which will be the most important case, the establishment of low pressures at up to maximum 400 K is an alternative option.