Authors:Irena Vovk, Breda Simonovska, Samo Andrenšek, Teijo Yrjönen, Pia Vuorela, and Heikki Vuorela
Extraction of onion (
L.) with 80:20 (
) methanol-water in water by rotation planar extraction (RPE) and medium-pressure solid-liquid extraction (MPSLE) has been studied systematically. Rotation planar extraction was studied by use of an ExtraChrom separation instrument prototye. Only rotation planar extraction performed by use of the ExtraChrom enabled efficient extraction of dried onion. The equilibration time proved to be the most important variable in the extraction. The particle size of the sample had a variable effect on extraction efficiency, mainly because of the carbohydrates predominating in the extracts. It was possible to extract oligofructans with a degree of polymerization of up to 12, and these were the main components of the extract. Fructose, glucose, and saccharose, in total, accounted for 10% of the mass of the extract; their mass ratio in the extract was 3:1:6. After mild hydrolysis of the extract with oxalic acid only fructose and glucose were obtained. Although TLC screening of the extract before acid hydrolysis detected no flavonoids, one phenolic acid was observed. After acid hydrolysis with hydrochloric acid, quercetin could be detected.
Soil water balance was studied in a 25-year-old experiment, on chernozem soil, in different crop-rotation systems (mono-, bi- and triculture) in dry (2007) and rainy (2008) seasons, in maize production. Soil water deficit values in maize production were much lower in 2008 than in 2007 in non-irrigated and irrigated plots of three crop rotation systems because of favourable precipitation supply. We found difference between the water deficit values of two irrigation treatments. We measured lower values in irrigated plots of three crop-rotation systems before sowing: non-irrigated plots in monoculture 105 mm, in biculture 101 mm, in triculture 121 mm and irrigated plots in monoculture 90 mm, in biculture 91 mm, in triculture 111 mm. Soil waterstock started to decrease with the rise in average temperature and, despite an increase in precipitation quantity, we calculated higher water deficit values. Precipitation in August and the high average temperature intensified the water deficit. Water deficit showed its highest values in early September. We examined the water balance of the soil profile in 0–2.0 m and we concluded that the water deficit of the 0.8–1.2 m soil layers was most intensive in both non-irrigated and irrigated treatments, because of significant root mass. Our results showed that irrigation had a more important influence on the yield in a dry cropyear (2007 characterized by abiotic, water stress) than in an optimum water supply cropyear (2008).
Thermodynamics of system composed of three possible isomeric dideuteriocyclobutadienes has been studied based on the best available theoretical structural and vibrational parameters. Particular attention is paid to the recently raised question of applicability of the conventional (one term proportional to T3/2) expression for the rotational part of partition functions of the isotopomers at low temperatures T in comparison with more sophisticated approximations viz. containing an additional term proportional to T1/2 or even a correction proportional to T–1/2. Mutual relative stabilities of the isomeric isotopomers are evaluated as well as the isomerism contributions to the system thermodynamics. The three approaches are proved to yield very close results even at very low temperatures. Consequences for structure interplay in isomeric isotopomer sets are discussed.
Suppose that f: ℝ → ℝ is a given measurable function, periodic by 1. For an α ∈ ℝ put Mnαf(x) = 1/n+1 Σk=0nf(x + kα). Let Γf denote the set of those α’s in (0;1) for which Mnαf(x) converges for almost every x ∈ ℝ. We call Γf the rotation set of f. We proved earlier that from |Γf| > 0 it follows that f is integrable on [0; 1], and hence, by Birkhoff’s Ergodic Theorem all α ∈ [0; 1] belongs to Γf. However, Γf\ℚ can be dense (even c-dense) for non-L1 functions as well. In this paper we show that there are non-L1 functions for which Γf is of Hausdorff dimension one.
Authors:V. B. Lazarev, K. S. Gavrichev, and V. E. Gorbunov
Low temperature heat capacity of ammonium, rubidium and cesium perbromates has been studied by method of adiabatic calorimetry. Anomaly of the heat capacity of cesium perbromate has been found, which corresponds to a structural phase transition. The separation of heat capacity into components has been carried out by the additive scheme. The torsion oscillation of BrO4− anions in solid perbromates at low temperatures has been found. Ammonium ions retardedly rotate aroundC2 axes in the crystal lattice of NH4BrO4.
Authors:Danijel Jug, Bojan Stipesevic, Ivan Zugec, Drazen Horvat, and Marko Josipovic
The trial for winter wheat (
Triticum aestivum L.
) or spring barley (
Hordeum vulgaris L.
) in rotation with maize (
Zea mais L.
) on lessive-pseudogley in semiarid to semihumid climate of Eastern Croatia was set up during years 1996–1999 with five soil tillage systems: PL) Conventional tillage based on ploughing; PD) Conventional tillage after diskharrowing for previous crop in preceding season; DP) Diskharrowing after conventional tillage for previous crop in preceding season; DD) Continuous diskharrowing, and CD) Chiselling and diskharrowing. During first and second season (1996/97 and 1997/98), recorded winter wheat grain yields were not different, with PL having the highest and DD the lowest yield. Maize showed next differences in first season: PL=PD>CH=DD=DP, and in second season PD=PL=DP=CH>DD. In 1999, spring barley replaced winter wheat, and yields were: PL>DP>PD>CD>DD. Maize yields recorded were: PL>PD>DP>CH>DD. The grain yield results, together with hectoliter mass and mass of 1000 grains, supported that PL can be replaced with other tillage systems for winter wheat and spring barley, whereas continuous diskharrowing may have substantially lower yields for maize during unfavourable years.
Total nitrogen content in organic explosives and relate materials can be determined by fast neutron activation analysis (FNAA)
to an absolute accuracy comparable to wet chemical or combustion analysis, i.e. to within less than 0.1% N. This is accomplished
by dual-axis rotation of the sample and a carefully selected reference standard during neutron irradiation. The optimum reference
standard is one of similar composition, density, weight and volume to the sample being analyzed. Rapid pneumatic transfer
of organic explosives of low mechanical shock sensitivity poses no special safety problems. For large numbers of individual
samples, a multiple sample irradiation system with single-axis rotation can be used for more rapid analysis. Precision and
accuracy by this method are not as good as compared to a dual-axis rotation technique. Absolute accuracy for total nitrogen
is in the order of 0.2%. This method is useful only for those reactions where the half-life of the product is long enough
to allow for sequential counting of multiple samples for a single irradiation.