Berg's effect

A Neumann problem for the Laplace equation is considered outside a three dimensional straight cylinder. The value of a solution O" at space infinity is prescribed. The Neumann data aO" / an ( n is the outer normal of the cylinder) is assumed to be independent of the spatial variables on the top and the bottom and also on the lateral part of the boundary of the cylinder. The behavior of the value of O" on the boundary is studied. In particular, it is shown that O" is an increasing function of the distance from the center of the top ( respectively, the bottom) if a(J" / an > o on the lateral part and a(J" / an is the same constant on the top and (respectively, the bottom). An analogous statement is shown for O" on the lateral part. In the theory of crystal growth O" is interpreted as a supersaturation and cylinder is a crystal. The value aO" / an is the growth speed. The main contribution of this paper is considered as the first rigorous proof of Berg's effect when the crystal shape is a cylinder

Effect of rotors on the parameters of hop drying in belt dryers

ArticleThis article contains a design and verification for a technical solution aimed at optimising the hop drying process in belt dryer and at increasing the quality of the final product. Above the first belt of our belt dryer two evenly distributed double-arm rotors were installed and tested in operation to improve the permeability of the drying air through a flattened hop layer, as well as to improve the speed of drying. The measurements carried out in operation and comparing the drying process with the rotors switched on and off concluded that by inclusion of rotors the hop layer becomes more permeable, and when switched on, the rotors have a positive effect on faster reduction of the relative humidity and on increase of the drying air temperature. With rotors switched on, the percentage drop in the drying air relative humidity at the third inspection window of the first belt, compared to the first inspection window, was 41% on average (values obtained from data loggers and fixed sensors), the drying air temperature increased by 29%, and the hop moisture content decreased by 12%. Whereas with rotors switched off, the drop in the drying air relative humidity was only by 26% on average, the drying air temperature increased only by 14%, and the hop moisture content decreased by 12%. Based on long-term monitoring of fuel consumption during the whole harvesting season starting 2011 until 2017 inclusive, the average annual consumption of LFO (2011–2014) results in 494 L t -1 operating without rotors, and 431 L t -1 when operating with rotors (2015–2017). This implies that due to the implementation of rotors, the fuel saving being 13% is significant

Determination of moisture ratio in parts of the hop cone during the drying process in belt dryer

ArticleThe paper deals with monitoring the moisture content of hop cones and their parts (strigs and bracts) in PCHB 750 hop belt dryer. When drying hop cones, the critical point is the sufficient drying of the strig. These are therefore dried to a moisture content o f 6 to 8%. This exact moisture provides a sufficient guarantee ensuring that the strig is dried up. On the other hand, bracts are dried up to such a level which makes pressing the hops impossible. Therefore, after drying, the bracts are remoistened. This i s called hops conditioning. After conditioning the moisture content of hops is optimal, ranging between 8 and 11%. There is no doubt that drying or any further moistening does not benefit the hop cone. During the experiment, the moisture content was determ ined regarding the whole hop cones as well as the bracts and strigs separately, the samples of which had been taken from the hops prior to entering the dryer, from different parts of belts in the dryer and subsequently before and after the conditioning. Th e moisture content was determined by means of Mettler HE53 moisture analyzer. After the bracts and strigs had been dried, we calculated their weight ratio which was approx. 90% of bracts and 10% of strigs. Based on this ratio the weighted average was calcu lated which corresponds to the moisture content of the whole hop cone. The measured values indicate that the average moisture content of hops below 10% was already at the beginning of the third belt of the dryer. The hops had been unnecessarily overdried a long the whole third belt. Another output refers to the moisture ratio of hop cones, bracts and strigs in different parts of the dryer. The obtained values will serve as a basis for the follow - up design of a device for monitoring the dryer parameters and i ts visualisation

Analysis of hop drying in chamber dryer

ArticleThis article is aimed at the analysis of the hop drying process that has been carried out in the chamber dryer of Rakochmel Co. Ltd. in Kolešovice with the Saaz hop variety. The values measured by means of dataloggers as well as fixed sensors show an identical trend. When the hops fall over from one slat box onto another, the drying air temperature declines and the relative humidity rises. A sharp increase in the relative humidity gradually decreases starting with the first slat box and finishing with the emptying conveyor, which points to a gradual levelling of the relative humidity and hop moisture. The hop moisture content, determined from laboratory samples, logically decreases depending on the measurement time. In comparison to belt dryers, chamber dryers clearly ensure continuous and more gentle drying during which the hops are not overdried and a moisture content of 10% is achieved practically only at the outlet of the dryer prior to conditioning

Kinematics of Tycho-2 Red Giant Clump Stars

Based on the Ogorodnikov-Milne model, we analyze the proper motions of 95 633 red giant clump (RGC) stars from the Tycho-2 Catalogue. The following Oort constants have been found: A = 15.9+-0.2 km/s/kpc and B = -12.0+-0.2 km/s/kpc. Using 3632 RGC stars with known proper motions, radial velocities, and photometric distances, we show that, apart from the star centroid velocity components relative to the Sun, only the model parameters that describe the stellar motions in the XY plane differ significantly from zero. We have studied the contraction (a negative K-effect) of the system of RGC stars as a function of their heliocentric distance and elevation above the Galactic plane. For a sample of distant (500--1000 pc) RGC stars located near the Galactic plane (|Z|<200 pc) with an average distance of d=0.7 kpc, the contraction velocity is shown to be Kd= -3.5+-0.9 km/s; a noticeable vertex deviation, lxy = 9.1+-0.5 degrees, is also observed for them. For stars located well above the Galactic plane (|Z|>=200 pc), these effects are less pronounced, Kd = -1.7+-0.5 km/s and lxy = 4.9+-0.6 degrees. Using RGC stars, we have found a rotation around the Galactic X axis directed toward the Galactic center with an angular velocity of -2.5+-0.3 km/s/kpc, which we associate with the warp of the Galactic stellar-gaseous disk.Comment: 23 pages, 7 figures, 4 table

A caricature of a singular curvature flow in the plane

We study a singular parabolic equation of the total variation type in one dimension. The problem is a simplification of the singular curvature flow. We show existence and uniqueness of weak solutions. We also prove existence of weak solutions to the semi-discretization of the problem as well as convergence of the approximating sequences. The semi-discretization shows that facets must form. For a class of initial data we are able to study in details the facet formation and interactions and their asymptotic behavior. We notice that our qualitative results may be interpreted with the help of a special composition of multivalued operators

Elaboração de barra de cereal sabor maracujá-do-mato.

Este trabalho apresenta uma metodologia para a elaboração de barra de cereal sabor maracujá-do-mato, os ingredientes necessários, proporções e formulação a ser seguida.bitstream/item/140473/1/COT163.pd

Quasi-static evolution of 3-D crystals grown from supersaturated vapor

Gonda and Gorni (T.Gonda, H.Gomi, Ann. Glaciology, 6 (1985), 222 224) have grown large elongated ice crystals from supersaturated vapor. Theoretrically this problem may be recast in a framework similar to that used by Seeger (A.Seeger, Philos. Mag., ser. 7, 44, no 348, (1953) 1-13) for studies of planar crystals. The resulting set of equations is of Stefan type. We also include the Gibbs­Thomson relation on the crystal surface. In order to make this system tractable mathematically we assume that the \\\1lff crystal is a fixed cylinder. Subsequently we study a weak form of our system. We show local in time existence of solutions assuming that the initial shape is an arbitrary cylinder. We comment on properties of weak solutions