Studies on the degradation of atrazine by bacterial communities enriched from various biotopes

Degradation of 14C-ring labeled atrazine (2-choloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) by bacterial populations from soil, waters and activated sludges was investigated and compared with non-biological decomposition in sterile solutions. Within two weeks, 0.6% Cl-deethyl- and 0.1% Cl-deisopropylatrazine had been formed in sterile 0.02 M phosphate buffer, pH 7.2. In biodegradation studies, bacterial populations were enriched and incubated in media containing atrazine and high or low levels of nutrients. Nutrient supply had a strong effect on the fate of atrazine in bacterial cultures, whereas the origin of bacteria was of minor importance. In 31 of 33 mixed populations investigated, the herbicide was largely converted to unidentified compounds. Incubation with high levels of nutrients resulted in 17% to 57% of these compounds being constant after one and two weeks of incubation. In parallel experiments with low nutrient supply, the compounds were present in amounts of 7% to 57% after one week. The proportions of the unidentified compounds dropped within the second week of incubation, while atrazine reappeared correspondingly. The amounts of dealkylated metabolites generally did not exceed those of sterile solutions. The results indicate that atrazine is not degraded by bacteria but bound, thus simulating biodegradation. Evidence is presented that physicochemical decomposition of the herbicide is more significant than microbial degradation.     

The temperature dependence of the thermal conductivity of narrow fractions of ozeksuat oil

The theory of corresponding states can be used to investigate the thermal conductivity of narrow fractions of oil.     

A Model‐Based Analysis of Secure Video Transmission Based on IPSec and IPv4

A promising solution to protect wired Internet networks is to use the Secure Internet Protocol (IPSec); however, this has some drawbacks, particularly on the quality of service (QoS). This paper aims at evaluating the video traffic QoS in terms of end‐to‐end delay and packet loss rate. Based on some basic assumptions, our analysis shows that the performance with IPSec is rapidly inferior to the IPv4 performance. We thus suggest adding some QoS parameters into IPSec in order to achieve a compromise between QoS and security.     

Hydrodynamics of Shaft Drying of Granulated Poly(Ethylene Terephthalate)

The effect of the poly(ethylene terephthalate) granule size on bed hydrodynamics in blowing with an ascending stream of drying agent was investigated. It was found that the pressure loss of the bed is more dependent on its height and average air speed the smaller the equivalent granule diameter is.     

Hyperbolic equation of heat conduction for dispersed systems

The possible use of a hyperbolic equation to describe heat conduction in dispersed systems is analyzed.     

The relationship of magnitude of shrinkage with internal stress in Lavsan (polyethylene terephthalate) monofilaments

Conclusions With polymers which can crystallise on being stretched, the relationship between shrinkage and internal stress is conditioned not only by orientation of the macro-molecular chains, but also by the ratio of the amorphous and the crystalline zones.All-Union Glass Fibre Research Institute (VNIISV). Translated from Khimicheskie Volokna, No. 3, pp. 47–49, May–June, 1969.