The Hg-, Cd- and UO2-targets bombarded by protons have been treated using the sublimation and evaporation techniques. The Hg and Cd nuclei have
been separated from non-isotopic products by distillation in the hydrogen stream. The separation of the groups of Re, Os,
Ir, Mo, Tc and Ru oxides has been carried out in the air stream. No monotonic temperature dependence of the Tl, Ru, Mo, Tc,
Te, Pb and Po release has been observed in the oxidation of the UO2-ceramics in the air stream. The values of (−ΔH
) of volatile products adsorbed on quartz have been determined from the chromatographic data. The relation between the adsorption
) and the standard sublimation heat (ΔH
subl.) has been found to be linear, i.e. −ΔH
(subl.). As an example of the thermochromatographic generator of isotopes, the separation of99Mo to99mTc has been investigated.
Authors:Cristian Vulcu, Aurel Stratan, and Dan Dubina
Dual-steel structural systems, in which mild carbon steel is used in dissipative members while high strength steel is used in non-dissipative ‘elastic’ members, can be very reliable and cost efficient. Because present seismic design codes do not cover this specific configuration, a research project started with the aim to investigate and evaluate the seismic performance of dual-steel building frames. The frames are considered to be moment resisting frames, dual concentrically braced frames and dual eccentrically braced frames. The paper makes a short description of the research project and the experimental program to be performed at the ‘Politehnica’ University of Timisoara.A number of numerical simulations have been performed for the beam-to-column joints that will be tested with the aim to assess their behavior under monotonic as well as cyclic loading. The material model used in the numerical simulations was calibrated based on the results from tensile tests. The assumptions considered in the modeling of the specimens, the loading procedure, as well as the results from the numerical analysis are finally presented.
To avoid the problems associated with the Euclidean distance for the calculation of plot-to-plot dissimilarity, a variety of alternative measures have been proposed. Among them, the chord and the Hellinger distances are both obtained by first transforming separately the species abundances in each plot vector and then by calculating the Euclidean distance on the chord-transformed or the Hellinger-transformed data. However, although both measures are routinely used by ecologists as substitutes for the Euclidean distance, they have very different properties. In this paper, using a modified version of Dalton's principle of transfers, I will show that, unlike the Euclidean distance, the chord and the Hellinger distances are not monotonic to changes in absolute abundances. Therefore, they are not interchangeable with the Euclidean distance. The moral of this story is that although dissimilarity may appear an intuitively simple concept, the properties of even the best-known indices are not fully understood. Therefore, a clear understanding of old and new coefficients is needed to evaluate their ability to highlight relevant aspects of compositional dissimilarity among plots.
This paper presents a method for measuring indoor radon concentrations using a commercially available air-purifying respirator
filter as a component of the radon monitor. The filter used was Survivair’s NIOSH (National Institute for Occupational Health
and Safety)-approved 100800 model. The method is based on the diffusion of radon gas into the activated carbon of the filter
and the measurement of the radioactive daughters resulting from the radon decay. The photopeaks of the 214Bi daughter gamma rays (0.609 MeV) were analyzed with a Hyper-Pure Germanium (HPGe) detector and a multichannel system. A
monotonically increasing and very close to linear response relation between the integrated area under the 214Bi photopeak and the radon concentration of the activated carbon was found. A well-defined relation held for radon levels
ranging from 15 to 4,700 Bq/m3. This procedure results in highly reproducible and reliable measurements of indoor radon levels. Interesting applications
include the investigation of radiological accidents involving radon and the retrospective measuring of indoor radon concentrations
by analyzing the filters of the respirators worn by personnel working during the relevant period.
The crustal and uppermost mantle structure beneath the Mátra Mountains has been investigated by means of the inversion of teleseismic P-wave receiver functions. Earthquakes recorded at the PSZ station in the period 1995-2000 with epicentral distances of between 20° and 100° and with magnitudes greater than 5.5 have been selected for analysis if their signal-to-noise ratio was sufficiently high. Source equalisation has been carried out to gain the radial and tangential receiver functions. The traces from similar backazimuths and distances were stacked to improve the data quality. The inversion of teleseismic waves coming from the north-east and the west shows that in the upper part of the crust the S-wave velocity has strong positive gradient, the middle crust exhibit almost uniform velocities, while in the lower crust and uppermost mantle the velocity increases monotonically. Velocity profiles for the eastern backazimuths are similar to the previous ones in the case of the upper and middle crust and uppermost mantle, however in the lower crust a low-velocity zone can be observed. The properties of polarity distribution of tangential receiver functions can be associated with WNW-dipping lower crustal interfaces.
The purpose of the study was to assess the effectiveness of meal replacement diets in body weight management and the impact on the body composition of working age people, when the participants purchased the products and followed the weight loss program outside the clinical trial.In weight loss programs (3.98±2.29 months), 79 participants (56 women, 23 men) lost an average of 10.19±6.1 kg of their body weight, 11.47±9.15 cm in the waist circumference, and 5.29±5.46 of the percentage of body fat. Replacing two meals a day was an effective way to loose weight because of its simplicity and convenience of use. The cost of the products and the monotony of the diet were the main causes of abandoning the diet. After the diet subjects were followed for an average of 11.28±8.1 months, and for the entire group of participants an average weight gain of 2.86±3.02 kg was observed compared to the minimum weight (31.5% of weight lost). Long-term maintenance was better in the subjects that replaced one meal a day, but is still a challenge and required further research.
The addition of suitable cross-linking agents with norbornene-based monomers has significant effects on the thermal properties
of the resulting polymers formed by olefin metathesis. Ethylidene norbornene (ENB) and endo-dicyclopentadiene (endo-DCPD) were mixed separately with various loadings of three different cross-linking agents and then polymerized with the addition
of Grubbs’ catalyst. The polymerization kinetics and resulting glass transition temperature (Tg) of the systems were evaluated by differential scanning calorimetry (DSC).
The addition of the first cross-linking agent, norbornadiene (CL-1), to both endo-DCPD and ENB resulted in decreasing glass transition temperatures with increasing concentrations. In contrast, the addition
of the other two cross-linking agents (CL-2 and CL-3), which were both custom synthesized bifunctional norbornyl systems,
to both endo-DCPD and ENB resulted in a monotonic increases in Tg with cross-linker concentration. By tailoring the loading of these custom cross-linking agents, the properties of these polymer
systems can be controlled for various applications, including self-healing composites.
Authors:Pál Jakusch, Tímea Kocsis, Ilona Kovácsné Székely, and István Gábor Hatvani
The aim of the present study is to extend the applicability of MRI measurements similar to those used in human diagnostics to the examination of water barriers in living plants, thus broadening their use in natural sciences. The cucumber, Cucumis sativus, and Phillyrea angustifolia, or false olive, were chosen as test plants. The MRI measurements were carried out on three samples of each plant in the same position vis-a-vis the MRI apparatus using a Siemens Avanto MRI scanner. Two different relaxation times were employed, T1, capable of histological mapping, and T2, used for the examination of water content. In the course of the analysis, it was found that certain histological formations and branching cause modifications to the intensity detected with relaxation time T2. Furthermore, these positions can also be found in T1 measurements. A monotonic correlation (cucumber: ρ = 0.829; false olive: ρ = –0.84) was observed between the T1 and T2 measurements. In the course of the statistical analysis of the signal intensities of the xylems it was concluded that they cannot be regarded as independent in a statistical sense; these changes rather depend on the anatomic structure of the plant, as the intensity profile is modified by nodes, leaves and branches. This serves as a demonstration of the applicability of MRI to the measurement of well know plant physiological processes. The special parametrization required for this equipment, which is usually used in human diagnostics, is also documented in the present study.
At a given surfactant-surfactant ratio, the enthalpies of transfer ΔH (W→W+S) of pentanol 0.03m from water to sodium dodecylsulfate (NaDS)-dodecyldimethylamine oxide-water mixtures as functions of the surfactants mixture
concentration (mt) were determined. ForXNaDS=0.9, ΔH (W→W+S) increases monotonically withmt such as observed for pure surfactants. ForXNaDS=0.12 and 0.3, ΔH (W→W+S) increases withmt up to 0.12m beyond which it decreases withmt. AtXNaDS=0.6, two monotonic curves can be distinguished in the ΔH (W→W+S)vs. mt trend. Experimental data were fitted through an equation previously reported for additives in pure surfactants derived by
assuming the pseudo-phase transition model for the micellization and a mass action model for the distribution of the additive
between the aqueous and the micellar phases. This method did permit to simultaneously obtain the distribution constant of
the alcohol between the aqueous and the micellar phase (and, then, the standard free energy of transfer) and its enthalpy
of transfer from the aqueous to the micellar phases. By combining these properties the standard entropies of transfer were
calculated. From these results, the excess properties of pentanol in the mixed micelles were calculated as a function of the
mixture composition. The excess enthalpies and entropies are positive and compensate with each other leading to null values
for the excess free energies in the whole range of the mixed micelles composition.
A cardiorespiratoricus fittség (aerob kapacitás, VO2max) mértéke
nagymértékben meghatározza az életkilátásokat, ezért növelése az egészség
helyreállítására a szervezett edzésprogramon alapuló multidiszciplináris
rehabilitáció egyik fő célja – a többi rizikótényező csökkentése
mellett. A (tünetek által behatárolt) egyenletes iramú testmozgások mellett
egyre kiterjedtebb az interval jellegű „edzés”. Ilyenkor a néhány perces
intenzívebb szakaszt hasonló tartamú vagy hosszabb könnyű mozgás vagy passzív
pihenő váltja (mérsékelt intenzitású interval edzés: MICE). Az intenzív szakasz
történhet a tünetküszöb alatti maximális intenzitással is (high-intensity
interval training: HIIT), sőt igen rövid, 10–30 másodperces szupramaximális és
hosszabb pihenőszakaszok váltakozásával is (sprint interval training: SIT). Ezek
előnye a 30–40%-kal rövidebb edzéstartam, emellett sokak számára ezek
elfogadhatóbb edzésformák, változatosabbá teszik a programot, hatásosabban,
extra veszély nélkül. Az interval jellegű rehabilitációs edzésprogramok helyet
kapnak az egyéb kórállapotok kezelésében is, káros mellékhatások nélkül. Orv
Hetil. 2018; 159(33): 1346–1352.