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The C-PORCA/HELIOS models have been used at NPP Paks as basic core neutron physics calculation tools for many years. C-PORCA is a node-wise diffusion model for the purpose of 3D core analysis. HELIOS is a well-known neutron transport code. Its utilisation at Paks NPP has a dual use. This code is a basic tool for preparation of homogenised few-group neutron cross sections inside fuel nodes and areas without fuel and the flexibility of HELIOS allows using it for testing. During the last decade some new kind of fuel assemblies were utilised in Paks. In order to ensure the accuracy and performance requirements of the off-line core analysis and in-core monitoring, continuous development and testing of the codes have been performed. In this paper the main characteristics of the diffusion solver applied in the C-PORCA model are described. The accuracy of this solver is also demonstrated on the basis of comparisons with different international references available in hexagonal geometry. The C-PORCA results have been compared against benchmark data produced in the framework of the AER (Atomic Energy Research) community in recent decades. All presented comparisons illustrate that the accuracy of the C-PORCA diffusion solver is excellent.

This paper compares three earlier model projections with the shares of power technologies proposed in the National Renewable Action Plans (NREAPs) of the European Member States (MS). We aim to give deeper insight to the renewable energy policy support and policy formulation processes and interaction between the various MS and the EU. In some MS governments built their plans solidly on model outputs while in other cases they overwrote projections. Analysing their interactions proves to be useful not only for refining further the projections concerning the power portfolios in the European countries, but can provide further information for the different stakeholders in decision making process in the renewable energy context (decision makers, research institutions, lobby organisations). At the same time such analysis can further enhance the interaction between the relevant stakeholders and the feedback can result in increasing the effectiveness of the policy formulation.

AbstractAccording to [2] the capability of providing good bounds for the size of a maximum clique in a graph is a critical ingredient of an efficient clique search algorithm. In order to establish upper bounds of the size of a maximum clique we introduce some new coloring schemes using s-clique free partitioning. A complexity result will show that finding the optimal number of colors is an NP-complete problem. This can be interpreted loosely as a computational limitation. To overcome this difficulty for practical purposes we suggest various greedy coloring procedures.

Barkhausen noise properties of amorphous and nanocrystallized FINEMET type soft magnetic materials are investigated. It is obtained that the amorphous-nanocrystalline tranformation has a well observable effect on both the root main square, RMS, values and the critical exponents of the probability distributions of peak heights and durations.

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Finemet type materials show extremely soft magnetic behavior with excellent and in wide range on-demand variable macroscopic parameters [1]. Requirements for the most important magnetic parameters (e.g. permeability, coercitive force, saturation, loss) are determined by the targeted applications. We report results on the optimization of crystallization treatments and parameter tailoring by magnetic field induced anisotropy. As compared to the most widely used magnetic materials our samples have parameters of real measure of excellence.

We performed indoor competition experiments between algae and Lemna gibba L. in order to unravel mechanisms of competition. To separate effects of shading and physical interference from nutrient competition we grew the two groups physically separated while sharing the same water. A multifactorial design was used with five levels of initial nitrogen concentration (0.1? 50 mg N l?1) and four shade levels mimicking 0 ?100 % duckweed shade on the algal compartment. In the experiments in which algae were not shaded, the growth rate of Lemna was reduced strongly (60 ? 62 %) at moderate initial nitrogen concentrations (0.1?1 mg N l ?1). The impact of algae was less at high N-loading and if algae were shaded. The reduction in the chlorophyll content of the fronds was even more dramatic (72 ? 80 %). Analyses of nutrients and pH indicated that algae inhibited the growth of Lemna by the removal of N, P and Fe, but also by their photosynthetic effect on pH. When algae and duckweeds were grown together, floating algae occurring at high nutrient levels partly covered the duckweeds and reduced the growth further than in the absence of physical contact. Since under those conditions Lemna growth was still marked, it seems likely that on the long run Lemna will always expand sufficiently to outcompete the algae at high nutrient levels.

It has been shown that the chemical nature of electrodeposited rhenium species depends on the H 2SO 4 concentration in the supporting electrolyte from which the deposition takes place. In dilute H 2SO 4, mostly ReO 2 and ReO 3 and traces of Re 2O 5 are deposited. With the increase of H 2SO 4 concentration, Re 2O 5 becomes the principal deposit; in H 2SO 4 solution in higher concentration than 10 M, solely Re 2O 5 is deposited. From highly dilute H 2SO 4 solutions (pH˜0.9), Re 0 is deposited, which oxidizes at 0.7 V. If the current density of deposition is higher than 80 mA/cm 2, thermodynamically two types of Re 0 are deposited and oxidized at 0.7 V and 0.95 V.

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The corrosion accelerating effect of rhenium oxides deposited onto ARMCO iron surface has been studied in aerated 0.5 H2SO4and 1 moldm−3HCl blank solutions and in the presence of 10 and 100 mgdm−3Re2O7. It has been shown that rhenium has a decisive effect on the acceleration of cathodic hydrogen evolution and, consequently, on the corrosion of iron.

Iron nanocrystallites of ball-milled iron powder, partially crystallized melt quenched amorphous alloys and polycrystalline multilayers were studied. The change in the hyperfine field at iron atoms due to grain boundaries does not exceed the experimental linewidth.

The structure and magnetic properties of soft magnetic nanocrystalline composites crystallised from amorphous ribbons are reviewed. The Fe-Early Transition Metal-Boron (Nanoperm-type) nanostructures are discussed in details and compared to the Si containing (Finemet) alloys. The nanocrystallization process was studied by calorimetry; the spatial dimension, the composition and the relative fraction of the bcc and the residual amorphous phases were investigated by X-ray diffraction and Mössbauer spectroscopy. A small fraction of Fe atoms (about 4%) was found which cannot be assigned either to the residual amorphous or to the bcc phase. It is suggested that the magnetic anisotropy of the bcc phase is decreased due to the dissolved Zr and B impurities. The Curie point and Fe atomic moments in the residual amorphous tissue are determined and compared to that of a macrosized amorphous phase of similar composition. The observed deviations do not scale with the average characteristic size of the amorphous phase and thus cannot be explained in the framework of the existing models. Magnetic dipolar coupling and tensile stresses between the grains of the different phases are suggested for explaining the soft magnetic behaviour of the nanostructures.

Palladium adsorbed on platinum has been shown to decrease the amount of adsorbed hydrogen because the site requirement of Pdadsis about 1.5 times higher than that of adsorbed hydrogen. Metal adsorption via the ionization of adsorbed hydrogen occurs in two steps: the first leading to bulk deposition. This is followed by bulk ionization and repeated reduction, producing the adsorbed metal layer. The electrosorption valency of the adsorbed Pd layer thus formed is about 1.8. The Pdadsdoes not desorb in Cl−‐free media.

A total of 1,230 prisoners convicted of various criminal offenses underwent AB0 blood group testing. Two hundred thirty of them were of Gypsy origin. The blood group distribution in two categories of the prisoners, i.e., that of the aggressive criminals and of those who committed intellectual crime, was also analyzed separately. Regarding the non-Gypsies the following observations were made: (1) The blood group distribution of the prisoners compared with the mean values of the population in general showed no difference. (2) The frequency of the blood group B in the aggressive group was found higher than in the intellectual group. (3) The proportion of the aggressive criminals reached 34.5% whereas that of the intellectuals only 17.0%.

Copper adsorption (underpotential deposition) was used for determination of real surface area of palladium. The method is compared with other electrochemical methods based on hydrogen and oxygen adsorption.

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Pd-Co catalysts on activated graphite support are more active in some liquid phase hydrogenations than any of the unalloyed metals. The bimetallic catalysts consisted of (i) unalloyed Pd phase detected by x-ray diffraction and thermogravimetric measurements, and (ii) alloy phase detected by thermogravimetric measurements.

Isomerization of n-pentane has been studied in a continuous-flow reactor at atmospheric pressure on Pt/Al2O3 catalysts modified by adsorbed bismuth and palladium. Lower activity and higher selectivity have been obtained on a catalyst modified by bismuth. Both activity and selectivity have decreased on a catalyst modified by palladium. After oxygen treatment the Pd−Pt/Al2O3 catalyst showed the most pronounced change in catalytic properties and its stability was lower than that of the unmodified Pt/Al2O3 catalyst.

γ-Al2O3-supported Bi−Pt and Pd−Pt bimetallic catalysts were prepared by electrochemical metal adsorption. Isomerization of n-pentane was studied over these catalysts in a pulse reactor. It can be concluded from the results that the properties of these catalysts differ substantially from the base Pt/γ-Al2O3 catalyst. On the modified catalysts conversion and the yield of i-pentane was found to be lower although selectivity was better. The ratio of cracking reactions was also lower than over the base catalyst.

Rédei's theorem asserts that if a finite abelian group is expressed as a direct product of subsets of prime cardinality, then at least one of the factors must be periodic. (A periodic subset is a direct product of some subset and a nontrivial subgroup.) A. D. Sands proved that if a finite cyclic group is the direct product of subsets each of which has cardinality that is a power of a prime, then at least one of the factors is periodic. We prove that the same conclusion holds if a general finite abelian group is factored as a direct product of cyclic subsets of prime cardinalities and general subsets of cardinalities that are powers of primes provided that the components of the group corresponding to these latter primes are cyclic.

The statement, that in a tiling by translates of ann-dimensional cube there are two cubes having common (n-1)-dimensional faces, is known as Keller's conjecture. We shall prove that there is a counterexample for this conjecture if and only if the following graphsΓn has a 2n size clique. The 4n vertices ofΓn aren-tuples of integers 0, 1, 2, and 3. A pair of thesen-tuples are adjacent if there is a position at which the difference of the corresponding components is 2 modulo 4 and if there is a further position at which the corresponding components are different. We will give the size of the maximal cliques ofΓn forn≤5.

Abstract: Positron lifetime measurements were carried out on pyrophyllite-1 Tc before and after heat treatment, chlorination and HF treatment. The lifetime spectra gave information about the changes of the defect structure of pyrophyllite due to the different treatments.

The paper presents an example for the technology level quality control system of house-like components, which was implemented at the University of Miskolc. The system is based on a coordinate measuring machine, a machining centre and a computer providing control. For series-produced components, the system can be used to perform automatic correction after measurement for the continuous assurance of quality.

The union of translates of a closed unit $ n$ $ {{\mathbf{e}}_1}, \ldots ,{{\mathbf{e}}_n}$ $ i{{\mathbf{e}}_j},\left\vert i \right\vert \leq k,1 \leq j \leq n$-cross. A system of translates of a $ (k,n)$-space and the interiors of its elements are disjoint, the translates form a lattice and each translation vector of the lattice has integer (rational) coordinates. In this paper we shall continue the examination of rational cross tilings begun in [2], constructing rational lattice tilings by crosses that have noninteger coordinates on several axes.

A γ-Al2O3 supported Pd−Pt bimetallic catalyst prepared by electrochemical metal adsorption has been tested in n-hexane dehydrocyclization. The Pd−Pt/Al2O3 catalyst, after calcination in oxygen followed by hydrogen treatment, showed higher activities and better selectivities for benzene and iso-hexane formation. The Pd−Pt/Al2O3 catalyst appeared to be less sensitive to the changes in the temperature of hydrogen treatment than the base Pt/Al2O3 catalyst.

Activity and selectivity data obtained in n-hexane dehydrocyclization over Pt/Al2O3 and Pd−Pt/Al2O3 catalysts exposed to different thermal treatment processes are compared. The ageing phenomena were most pronounced on catalysts treated in hydrogen at higher temperatures. The Pd−Pt/Al2O3 catalyst possessed lower cracking activity with a parallel increase of the selectivity for benzene and iso-hexanes.

A γ-Al2O3 supported Re−Pt bimetallic catalyst prepared by electrochemical adsorption has been studied in n-hexane dehydrocyclization, using the slug-pulse method. The activity of the Re−Pt/Al2O3 catalyst treated only in hydrogen was low, but markedly increased by a calcination step before hydrogen treatment. The modified catalyst showed higher activity and increased selectivities for benzene and iso-hexanes than the base Pt/Al2O3 catalyst.

It has been shown that hydrogen determined from the TPD curves of platinum saturated with hydrogen sorbed above room temperature is chiefly absorbed and not adsorbed hydrogen; this absorbed hydrogen has no effect on the charging curve.

A family of translates of a closedn-dimensional cube is called a cube tiling if the union of the cubes is the wholen-space and their interiors are disjoint. According to a famous unsolved conjecture of O. H. Keller, two of the cubes in ann-dimensional cube tiling must share a complete (n - 1)-dimensional face. In this paper we shall prove that to solve Keller's conjecture it is sufficient to examine certain factorizations of direct sum of finitely many cyclic group of order four.

A series of Pd-Pt/alumina catalysts were prepared by consecutive deposition of Pd onto supported Pt particles. Electrochemical model studies indicated that under very mild conditions in aqueous acetic acid the reduction of Pd2+ions occurred partly via the ionization of hydrogen adsorbed on Pt and partly by the slow oxidation of acetic acid. There was only a moderate change in the surface Pd/Pt atomic ratio during heat treatment in flowing hydrogen at 400°C, as determined by XPS analysis. The catalytic performance of the bimetallic catalysts was tested in the enantioselective hydrogenation of ethyl pyruvate and ketopantolactone, in the presence of cinchonidine. Pd was virtually inactive and acted as a site blocker, which decreased the size of Pt ensembles and hindered the formation of the bulky transition complex between the reactant and the chiral modifier. The intrinsically low activity and selectivity of Pd are discussed in the light of H/D exchange studies in deuterated ethanol.

Antibodies against some microorganisms, naturalhaemagglutinins, and organospecific autoantibodies were examined in bronchial secretions of 40 patients suffering from chronic obstructive bronchitis. The determinations were effected in sputa prepared for serological analysis by ultracentrifugation, ultrasonic treatment, and subsequent freeze drying. The lyophilized substance was redissolved in distilled water in a concentration of 100 mg/ml. The results were compared with the values obtained in the blood sera of the same patients.

It has been shown that alumina (or impurities in it) can be reduced under circumstances which are applied in the pretreatment of Pt/Al2O3 catalysts.

Zur Ermittlung des Geschwindigkeitsfeldes in einem rotationssymmetrischen Kanal vom Typ einer Halbaxialmaschine wurde ein entsprechendes Modell mit optischer Zugangsmöglichkeit des Strömungsraumes gefertigt und in eine Wasser-Messstrecke mit stabil einstellbaren Zuständen eingebaut. Im unbeschaufelten Kanal war mittels der Laser-Doppler-Velocimetrie vorerst die meridionale Durchströmung zu untersuchen. Die Ergebnisse sollen dem Vergleich mit Berechnungsergebnissen nach verschiedenen Ansätzen bzw. Turbulenzmodellen dienen. Die räumliche Krümmung der Kanalwände erschwert den Einsatz der Laser-Doppler-Velocimetrie erheblich. Auf die sich ergebenden Verhältnisse in einem solchen Fall und die erforderlichen Korrekturen wird im Beitrag eingegangen.