Polymorphic transitions of α-phenylcinnamic acid stereoisomers crystallized from various solvents (CHCl3, ethanol, diethyl
ether), precipitated with different acids (acetic acid or HCl) or sublimed have been studied by differential scanning calorimetry
(DSC). Measurements were also supplemented by powder X-ray diffractometry (XRD). Polymorphic transitions were not found for
any of the E isomer samples irrespective of the method of treatment. However, in heating-cooling cycles reversible transitions
could be detected for the Z isomer. On heating an exothermic peak was registered on samples sublimed, crystallized from ethanol
or diethyl ether before melting, while samples precipitated by HCl or crystallized from chloroform exhibited more complex
transitions. Here, endothermic effects were also observed. Enthalpy values for transformations (either for melting or polymorphic
and other transitions) are also given.
Authors:E. Győri, L. Tóth, Z. Gráczer, and T. Katona
Low velocity surface layers can significantly increase ground accelerations during earthquakes. When saturated sandy sediments are present, because of pore pressure increase, decrease of soil strength or even liquefaction can occur. Some volume change follows the dissipation of excess pore pressure after the earthquake resulting surface settlements. To determine the liquefaction probability and post-liquefaction settlement is very important for critical facilities e.g. for the site of Paks Nuclear Power Plant, Hungary. Pore pressure increase and so the liquefaction and surface settlements depend on the characteristics of seismic loading and soil parameters. To quantify the extent of these phenomena is rather difficult. Uncertainties arise both from the probabilistic nature of the earthquake loading and from the simplifications of soil models as well. In the paper, the most important semi-empirical and dynamical effective stress methods for liquefaction and post-liquefaction settlement assessment are summarized. Most significant contributors to the uncertainties are highlighted, and particular examples through the investigation of Paks NPP site are given. Finally, a probabilistic procedure is proposed where the uncertainties will be taken into account by applying a logic tree methodology. At the same time, the uncertainties are reduced by the use of site-specific UHRS and stress reduction factors.
Authors:T. Katona, B. Kanyár, J. Somlai, and Á. Molnár
The introduced method to determine the individual activities of the short-lived radon daughters in air is based on simultaneous
α- and β-counting of the sampled air collected on a filter. The measured curves of gross-α and gross-β intensities were decomposed
by sum of exponentials and the individual activities of the progenies were assessed. Furthermore, computer simulations were
carried out supplemented with aerosol measurements to describe the physical processes of radon progenies in air during the
experiments and to verify the suitability of the method.
Authors:P. Katona, T. Pilissy, A. Tihanyi, and József Laczkó
The effect of cycling cadence and crank resistance on the activity of hamstrings and quadriceps muscles was investigated during cycling movements of able-bodied subjects on a stationary bike with slow and fast speed against different resistance conditions. The ratio of average EMG amplitudes obtained in the two speed conditions (fast/slow) was computed in each resistance condition. This ratio is higher for both muscles if cycling against higher resistance. This shows that in higher resistance condition muscle activities are not only increased but the change of muscle activities with respect to cadence change varied according to resistance condition. Average EMG amplitudes increased at a higher rate with respect to change of cadence when cycling was performed in higher resistance condition. Besides, when cycling faster, hamstrings activity increased generally at a higher rate than that of quadriceps. The correlation between cadence and EMG amplitudes were also investigated. Considering hamstrings, this correlation was low and decreased as resistance increased. The correlation between the time required to drive one cycle and EMG amplitude is negative but in absolute value it is larger than the correlation of cadence and EMG amplitude.
Authors:M. Tóth, I. Szarukán, A. Nagy, T. Ábri, V. Katona, Sz. Kőrösi, T. Nagy, Á. Szarvas, and S. Koczor
The addition of synthetic 4-methoxy-2-phenethyl alcohol to the known attractant phenylacetaldehyde synergized attraction of the European corn borer Ostrinia nubilalis, the blend invariably catching 3 to 5 times more than phenylacetaldehyde on its own. Highest catches were recorded by the 1:1 blend. Both females and males were attracted, supposedly in the natural sex ratio of the local population. This improved bisex O. nubilalis attractant could be more efficient and more suitable for detection and monitoring purposes than previously know lures, making possible to draw more reliable plant protection decisions.