CALCULATION OF SCALE EFFECT ON TORQUE AND THRUST OF SCREW PROPELLER OF SHIPS

The values of torque and thrust coefficients of any propeller are different from the corresponding values of its model. This difference is known as scale effect. The significant fraction of this scale effect results from the fact that the friction conditions of the model and those of the propeller are different from each other. Based on this, there is a simple method for calculation of the correction of torque and thrust coefficient of screw propeller

Electron-phonon interaction in the solid form of the smallest fullerene C20_{20}

The electron-phonon coupling of a theoretically devised carbon phase made by assembling the smallest fullerenes C$_{20}$ is calculated from first principles. The structure consists of C$_{20}$ cages in an {\it fcc} lattice interlinked by two bridging carbon atoms in the interstitial tetrahedral sites ({\it fcc}-C$_{22}$). The crystal is insulating but can be made metallic by doping with interstitial alkali atoms. In the compound NaC$_{22}$ the calculated coupling constant $\lambda/N(0)$ is 0.28 eV, a value much larger than in C$_{60}$, as expected from the larger curvature of C$_{20}$. On the basis of the McMillan's formula, the calculated $\lambda$=1.12 and a $\mu^*$ assumed in the range 0.3-0.1 a superconducting T$_c$ in the range 15-55 K is predicted.Comment: 7 page

Detection of heat treatment of honey with near infrared spectroscopy

Heat treatment of honey is usually applied due to crystallized form is not preferred by the consumers and makes handling harder to producers and beekeepers. Our aim is to find a method that can detect heat treatment of honey even at lower levels. In the study honeys were heated at 40°C, 60°C, 80°C, 100°C for one, two, three and four hours. Moisture, pH, electrical conductivity, HMF, color were determined, and spectra of honeys were recorded with NIRS. Results showed that NIRS could distinguish the honeys heated at 40°C while HMF was able to detect higher than 60°C treatment at significant level

Susceptibility of European pear cultivars to Venturia pirina Aderh. infection at a variety collection in Hungary

Field sensitivity of 271 European pear genotypes were evaluated in a large variety collection of pear in Hungary during a nine yearssurvey. Substantial differences were detected in the rate of pear scab infection of leaves and fruits. Some 18 per cent of the inspected genotypesremained completely free of infection even in the years with weather favouring to the disease. On the other hand, 78 % of the inspected genotypeswere infected in some or more extent. The rate of infection was generally higher on leaves than on fruits. 18.6 % of the genotypes inspectedwere tolerant to leaf infection and their majority (81.1 %) were tolerant to fruit infection. Some one fi fth of the genotypes (19.7 %) were highlysusceptible to leaf infection but only minor rate of them (2.2 %) were highly susceptible to fruit infection. There were 44 genotypes that couldbe regarded as tolerant to pear scab leaf and fruit infection under fi eld conditions. Some of these genotypes may be suitable to commercial peargrowing with highly reduced chemical control against pear but their yield capacity and fruit quality should be evaluated