We study the passage of active and passive granular particles through a bottleneck under gravitational bias. The grains are pharmaceutical capsules with spherocylindrical shapes on a vibrating table. The vibrating ground plate is slightly tilted in order to break the in-plane symmetry and to give particles a motivation to move in a preferential direction. The passage through a narrow gate with openings comparable to the grain length is studied using video imaging. Particle positions and velocities are extracted from the recorded frames. We find striking differences between the behaviour of asymmetric, active capsules and symmetric, passive ones. The active grains show an astonishingly strong dependence of the passage rates on the gate width, while for passive grains, this dependence is linear as expected. The cumulative distributions of delays between subsequent particles passing the outlet, a key parameter in egress studies, also differ substantially between active and passive grains. Tilt angle and excitation parameters have only little influence on the observed dynamic features, they merely rescale time.
Nanobainitic structures were produced in a low alloy carburised steel at temperatures of 200, 250 and 300°C. Scanning electron microscope micrographs indicated bainitic ferrites formed with a thickness range of 30–150 nm. Wear test results revealed that the coefficient of friction for nanobainitic samples was smaller and narrower compared to that of the martensitic sample which showed higher and larger variations indicative of better wear performance for nanobainite samples. The wear mechanism of nanobainitic samples due to their tough matrix was oxidative which resulted in small debris and smaller fluctuations in coefficient of friction. The large variation in the coefficient of friction in the martensitic sample was believed to be because of the detaching of larger fragments from the worn surface.
Background and Aim: Aflatoxin B 1 is a common contaminant of poultry feed and has the highest rate of acute and chronic toxicity among all mycotoxins. Over the past decade, studies have well established the negative effects of aflatoxin B 1 on the health of poultry. Therefore, it is necessary to determine the maximum concentration of aflatoxin B 1 in poultry feed. Materials and Methods: In this study, in order to determine the aflatoxin B 1 concentration in poultry feed, 45 samples were collected via a simple random method during autumn 2018 and winter 2019, and then the concentration of this contaminant was measured by the ELISA method.
Results:The experimental results showed that the contamination range in the positive samples was between 6.44 and 18.34 µg/Kg. Moreover, the mean concentration of aflatoxin in contaminated samples was 10.5 µg/Kg. The concentration of contaminant in 46.66% of the samples exceeded the standard limit. Due to higher temperatures and suitable environmental conditions for the growth of fungi, the samples prepared in autumn were more contaminated than those prepared in winter.
Conclusion:The level of aflatoxin B 1 contamination in poultry feed in Sanandaj is high. In order to prevent the entry of this toxin into the human food cycle regular survey and monitoring of poultry feed by health institutions are necessary.
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