Влияние ультразвукового излучения на время всплытия микропузырьков воздуха

Представлены результаты экспериментального исследования влияния ультразвукового излучения, генерируемого дисковым пьезокерамическим элементом ЦТС-19, на время всплытия микропузырьков, выделяемых из пересыщенного воздухом водного раствора. Показано, что под действием ультразвука происходит объединение пузырьков в комплексы, что увеличивает скорость их всплытия. Зависимость времени всплытия от частоты излучения носит сложный характер, применение ультразвука с частотой 160 кГц может снизить время всплытия с 39,9 до 13,5 с. Результаты работы могут быть использованы для увеличения производительности установок очистки сточных вод методом напорной флотации. The paper presents the results of an experimental study of the effect of ultrasonic radiation generated by a piezoelectric ceramic disk on the ascent time of microbubbles released from an aqueous solution saturated with air. It was shown that being irradiated by ultrasound, the bubbles combine into complexes, which increases the rate of their ascent. Dependency of the ascent time on the frequency of ultrasonic radiation is of a complex nature; however, the use of ultrasound with a frequency of 160 kHz can reduce the ascent time from 39.9 to 13.5 s. The results can be used to increase the productivity of wastewater treatment plants by pressure flotation.

Model Direct Adaptive Control of Buck Converter by using MRAC

DC-DC converters are commonly implemented in effective packages. One of the regular varieties of DC-DC converters is dollar converter. The flexible controller techniques can decorate framework reaction not just like PID controller with steady parameter isn't hearty enough. The temporary reaction of PID controller exhibitions is multiplied depending on versatile issue. That lets in you to determine excellent placing for the control parameters underneath a few circumstance, a bendy element relying on MIT popular is carried out. Direct MRAC has a simple shape and wonderful execution in a few scenario. The proposed framework is regular and geared up to reach on the reaction of model reference superbly. Be that as it is able to, the react of the framework has straight away overshoot and pursue again the reaction of model reference. The ascent time, settling time, overshoot, and unfaltering country for step response are some destinations that decide if the adjustment additions art work as it should be. The confinement of bendy manage is the choice of the adjustment profits. The adjustment additions of the controller parameters are gotten with the aid of experimental increases.

Impact of Radiosonde Balloon Drift on Numerical Weather Prediction and Verification

Radiosonde observations employed in real-time numerical weather prediction (NWP) applications are disseminated through the Global Telecommunication System (GTS) using alphanumeric codes. These codes do not include information about the position and elapsed ascent time of the balloon. Consequently, the horizontal balloon drift has generally been either ignored or estimated in data assimilation systems for NWP. With the increasing resolution of atmospheric models, it is now important to consider the positions and times of radiosonde data in both data assimilation and forecast verification systems. This information is now available in the Binary Universal Form for the Representation of Meteorological Data (BUFR) code for radiosonde data. This latter code will progressively replace the alphanumeric codes for all radiosonde data transmitted on the GTS. As a result, a strategy should be adopted by NWP centers to deal with the various codes for radiosonde data during this transition. In this work, a method for estimating the balloon drift position from reported horizontal wind components and a representative elapsed ascent time profile are developed and tested. This allows for estimating the missing positions and times information of radiosonde data in alphanumeric reports, and then for processing them like those available in BUFR code. The impact of neglecting the balloon position in data assimilation and verification systems is shown to be significant in short-range forecasts in the upper troposphere and stratosphere, especially for the zonal wind field in the Northern Hemisphere winter season. Medium-range forecasts are also improved overall when the horizontal position of radiosonde data is retrieved.

The use of morphometric analysis to predict the swimming efficiency of two Neotropical long-distance migratory species in fish passage

This study investigated the external body morphology (based on morphometric data) and the swimming efficiency in fish passages (based on the ascent time in a fish ladder) of two Neotropical long-distance migratory species. The fish were collected in the fish ladder of the Porto Primavera Hydroelectric Power Plant (known as Engenheiro Sergio Motta), upper Paraná River, Brazil. The species differ in several morphometric ratios related to swimming performance. Prochilodus lineatus exhibited a higher muscle ratio and caudal fin length ratio. However, Leporinus elongatus showed higher values for the fineness ratio, a higher length from snout to pectoral fin base ratio, and a higher caudal peduncle depth factor. Although both species show good swimming performance, the characteristics listed above may enable L. elongatus to apply greater power and propulsion, allowing it to reach a high swimming speed and to exhibit greater efficiency than P. lineatus. Leporinus elongatus moves faster than P. lineatus and has a lower mean ascent time (1.39 hours) than P. lineatus (3.76 hours). Prochilodus lineatus would require a somewhat longer time to pass through the fish ladder.