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Sirvi Autor "Sander, J." järgi

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  • Pisipilt
    Kirje
    Differential thermal regulation of the growth of the bee colonies in the early spring period
    (2018) Jehlička, T.; Sander, J.
    This paper addresses the issue of the control of activity and growth of the bee colonies (brooding) in the early spring period. The bees are brooding up already in the late winter, and the intensity of brooding in this period is determined by daytime tempe ratures and sunshine hours that increase the temperature of the inner hive space. The objective is to design and verify a technology that would ensure the conditions for the optimal brooding in the early spring period and thus the numerically strong bee co lonies. The experimental part was based on the temperature regulation in the inner hive space. A preset temperature was maintained inside the hive by an electric heating system with regulation. A differential thermal regulation which enabled the optimal gr owth of the bee colonies in accordance with the phenophases was chosen for verification. To verify the proposed method, two groups of the bee colonies were assembled. One group of the bee colonies had a heating system with regulation installed inside the h ive. The second group of the bee colonies was in the hives without the heating system installed. The dependence of the brood area on time was monitored for the evaluation of both groups of the bee colonies. It was proven that the differential thermal regul ation enables the optimal growth of the bee colonies in the early spring period in accordance with the phenophases. The brood area increased evenly for the group of the bee colonies with a regulated temperature of the hive space, reaching a larger area.
  • Pisipilt
    Kirje
    Separation of dust particles in the low-pressure pneumatic conveying system
    (2019) Jehlička, T.; Sander, J.
    This paper focuses on the possibility of separation of dust particle created as a byproduct of technological processing of composite materials. The aim was to design and verify technology for the separation of dust particles from polydisperse granular mixtures, which are created by physical-mechanical processes of materials processing (crushing, sorting, machining or surface treatment of products such as grinding or polishing the surface). Under experimental conditions, a low-pressure pneumatic conveying system was designed and tested in operation, supplemented by a powerful electrostatic dust particles separation system. The entry requirement was to design a system that would be able to work with high separation efficiency using lowpressure suction. The designed separation conveying device consists of three parts: the conveyance section for the grain material suction and conveying, the coarse grain share cyclone separator and the electrostatic precipitator of the dust particles released from the air flow. Operational capacity of the proposed technology was verified by evaluating the separation efficiency of processing the polydisperse granular mixture resulting from the crushing of laser printer toner cartridges. These contain toner powder residues, which are the source of composite dust particles. The separation efficiency of the system was monitored according to the set pressure of the air in front of the electrostatic separator. Evaluation of the results thus obtained confirmed the operational reliability of the system at low-pressure operation and the high separation efficiency of the electrostatic separator under the set operation conditions.