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Denitrification is a key process in wastewater treatment since it is responsible for the effective nutrient removal. It requires anoxic conditions, where only chemically bound nitrogen is used as an oxygen source, and no aeration is applied. In suspended biomass systems the growth and homogenization of biomass is essential, high degree of mixing is required, which is achieved only by using mechanical mixers. Mechanical mixing performance relies on the mixing power determined by the equipment dimensions and rotational speed. In this paper the effect of three different rotational speed (rpm: 100, 400, 900 min-1) on flow field and mixing conditions are evaluated. As a result of the simulations, the acceptable flow field was achieved at 400 rpm. The outcome of this research is that the high degree of energy transfer from mixers to fluid flow deteriorated mixing efficiency.

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Abstract  

Pulse nanosecond fluorescence anisotropy decay has been used to study the mobility of tryptophan residues within fungal lipase fromHumicola lanuginosa. The decay of emission anisotropy of protein in native, inhibited and mutated form has been investigated in buffered water and 50% v/v glycerol solutions. The rotational motions of the lipase were analyzed in terms of two different kinetic models. It was found that the fluorescence emission anisotropy decay can best be desribed with two rotational correlation times: 0.63 and 5.45 ns in water and 0.98 and 10.70 ns and in 50% v/v glycerol solution. Using the same experimental conditions the decay of inhibited and mutatedH. lanuginosa lipase showed a similar biexponential character. These results are interpreted in terms of local or segmental motion arising from a mass of about 1083 daltons which corresponds to the ‘lid’-helix fragment of the enzyme.

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Natural compounds possess multiple biological properties, among others antioxidant activity. Phenolic compounds which exhibit excellent antiradical activity may act as scavengers of free radicals or prevent their formation. The main objective of the present research was the examination of the free radical scavenging activity of instant corn gruels with 0%, 1%, 3%, 5%, and 10% addition of dried cranberry fruits. The extrusion of gruels was carried out at varying rotational speeds of the plasticising system (80, 100, and 120 rpm). The study was developed using two methods: thin-layer chromatography–2,2-diphenyl-1-picrylhydrazyl (DPPH) test and spectrophotometric analysis. The findings confirm that the use of higher screw rotations during the extrusion entailed a higher antioxidant activity of the obtained extrudates. Also, a high activity was reported for the extruded corn gruels without additives. This, in turn, demonstrates an insignificant influence of the extrusion process on the biological value of the obtained products.

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Abstract  

In this paper, Hardy’s theorem and rotations characterized by complex Gaussians in the complex plane due to Hogan and Lakey are extended to complex spaces of several variables. We point out that conditions under which a function on the n-dimensional real Euclidean space has an analytic extension to the complex space. Moreover, we prove that the function is a rotation of a multiple of real Gaussians through some angle if the extension satisfies certain assumptions.

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The paper is an overview of issues related to the space creation of a building, possibilities of developing frame structure and connections of force distribution in the construction. In plane the force distribution can be compression, bending and tension. In space “enclosing” a geometric solid means space creation. In space as it is to be expected, the force distribution must be compression, bending and tension in two different directions at the same time. This can be really variant but in the case of surface or surface-like constructions generated by translations (and/or rotations) on one hand, there are some other surfaces, which cannot be generated by translations (and/or rotations), on the other hand, the dimension of the inside “forces” is not two but three (independent components of a two-by-two tensor either in the case of compression tension, or in the case of bending). By this, force distribution is more complicated in space than in plane.

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The theoretical and practical background of the similarity transformation together with the simultaneous estimation of local geoid undulations is presented.The mean features of the traditional network adjustment on the local ellipsoids are summarized and the different Hungarian networks and known geoid solutions are shortly described as the basic data of the test computations.The eigenvalue and eigenvector decomposition revealed that the seven parameter similarity transformation cannot be applied together with the simultaneous local geoid estimation because the rotations about the X and Y axes significantly destroy the condition of the normal equations.However, the replacement of the rotations about the X, Y and Z axes by the rotation about the ellipsoidal normal of the datum point can provide a very well conditioned solution, which takes into account the special role of the datum point of the astro-geodetic network adjustment.Based on the unit weights of the input data an optimal adjustment strategy is demonstrated from a computational point of view, where the five transformation parameters can be estimated together with a very large number of local geoid undulations. The geoid has to be known in the global reference system. The geoid unknowns describe only the relative position of this known geoid with respect to the local reference system.The application of the available and the simultaneously estimated local geoid solutions proved that neglecting local geoid heights has a most significant impact on the scale parameter, while it has no significant effects on the horizontal residuals from the statistical point of view.The small scale difference (1 ppm) and the small rotation (-0.5 arc sec) about the datum point and its ellipsoidal normal of the Hungarian local system with respect to the global GPS system demonstrate the high quality of the traditional measurements as well.

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Abstract  

An approach to the dynamic optimization of the age structure of scientific personnel in an organization is presented. The appropriate mathematical model describing the age rotation of scientific workers is formulated and the criterion for maximizing the integral productivity of available scientific personnel over given time horizon is introduced. The criterion is constructed by using such scientometric instrument as the curves of age productivity. The practical application of suggested approach is demonstrated by means of real example.

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Summary  

Cesium-137 methodology has been successfully used to assess soil erosion. Seven erosion plots were sampled to determine the 137Cs profile and to assess the erosion rates. Cesium-137 profile for native pasture plot showed an exponential decline below 5 cm depth, with little 137Cs activity in the superficial layer (0-5 cm). Cesium-137 profile for wheat-soybean rotation plot in conventional tillage showed a uniform distribution with depth. For this plot, the soil loss occurs more in middle than upper and lower level. Cesium-137 profile for wheat-soybean rotation and wheat-maize rotation plots in no-tillage showed a similar result to the native pasture, with a minimum soil loss in the superficial layer. Cesium-137 profile for bare soil and cultivated pasture plots are similar, with a soil erosion rate of 229 t ha-1 year -1 . In the plots with a conventional tillage a greater soil loss occur in middle than upper and lower level. In no-tillage cultivation plots occurs soil loss in lower level, but no sign of soil loss neither gain in the upper level is observed. Cesium-137 methodology is a good tool to assess soil erosion and the 137Cs profile gives possibility to understand the soil erosion behavior in erosion plots.

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In intensive irrigated farming systems, the way to improve productive efficiency depends on the proper management of resources. With the implementation of the Alqueva global irrigation system in the southern Portugal region of Alentejo, agricultural intensification is a reality that imposes to farmers the challenge of producing more and more efficiently, ensuring the farming systems sustainability. This work resulted from an on-farm demonstration project carried out in two locations in the Alqueva region. Water use and water productivity were studied during 2012/2013 and 2013/2014, in three double cropping systems: a maize monoculture (MM) and two rotations, barley + maize-barley (BM-B) and sunflower-barley + maize (S-BM). Maize yields were influenced by the length of the crop cycle. In the rotation BM-B, with a predominance of autumn-winter crops, water requirements were lower and the total volume of irrigation applied was approximately half of the monoculture (5930 m3/ha and 13,230 m3/ha, respectively). When the potential crop yield was reached, maize had the higher water productivity (the highest value achieved was of 2.7 kg/m3). Overall, as a result of the lower yields achieved, the water productivity values indicate a less balanced performance of the S-BM rotation.

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Progress in Agricultural Engineering Sciences
Authors: Evgeniy Gennadievich Ivanov, Boris Ivanovich Gorbunov, Alexander Valentinovich Pasin, Boris Alexandrovich Aryutov, and Alexei Ivanovich Novozhilov

Abstract

Background: Acoustic cavitation is the creation and collapse of cavitation caverns in liquid in an acoustic field with a frequency of f = 1–3 kHz. The acoustic-cavitation processes manifest themselves during the collapse phase, with high pressure gradient continuum deformation, with a multiple transformation of energy forms. Liquid whistles are widely used to create an acoustic field of high power, but their efficiency only reaches 6–12%. We propose a liquid whistle in the form of a vortex cavitator (analogue of the Ranque vortex tube) with a rotating body in which a reduction in the input power is predicted.

Objective: Verification of feasibility of using a rotating body in a vortex cavitator with a rotation co-directional to the operational pump impeller.

Method: The method for identifying the feasibility of using a rotating body is to exclude body from the prototype and directly connect vortex chamber outlet with the pump inlet, which ensures the most complete preservation of co-directional vortex component of the flux entering the pump impeller.

Results: The results of experimental studies confirmed the validity of the hypothesis to a greater extent, since we achieved an increase in pressure at the outlet of the pump and a decrease in power at the drive relative to the original design.

Conclusions: The feasibility of designing the vortex cavitator body with rotation capability has been established, which will provide a reduction in input power of at least 30% by a rotation of the body, co-directional with the impeller.

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