The Mössbauer spectrum of ferric oxinate exhibits and asymmetric quadrupole doublet. The modification of the dynamic Mössbauer parameters (to the equal values for each line) following the irradiation, was explained by the internal oxine ligands rotation inside of the octahedral coordination.
Authors:Antonio Greco, Alfonso Maffezzoli, Emanuela Calò, Claudia Massaro, and Roberto Terzi
Sintering of semi-crystalline polymers occurs in those industrial processes, such as rotational molding, where the material is heated in the absence of any external applied pressure [ 1 , 2 ]. Sintering of
Among forced-flow layer chromatographic techniques, the centrifugally-driven variety was first developed, and named centrifugal layer chromatography, in 1947 by Hopf. In the 1980s Nyiredy further developed the technique and renamed it rotation planar chromatography. This paper summarizes the classifications and applicability of versions of this technique.
The ammonium ion in the alkali halide lattice has the hindered rotational state. The rotational potential is expressed as
crystal field, which depends upon only one rotational motion. The tetrahedral ion receives an octahedral field in this system.
Four fundamental types of orientation appear due to the symmetry of ion and that of field. As the barrier height increases,
the rotational levels approach to the librational levels with tunnel splitting. In particular, the tunneling part in the ground
librational level is calculated using both free rotor bases and orientationally localized states. The level structure with
the degeneracy is elucidated, which is peculiar in each type of orientation. Thermal properties are shown as model calculations.
The neutron attenuation coefficient is determined in a double axis rotational system. The difference between a fixed system
and a double axis rotational system is shown and curves for the neutron attenuation coefficient for the last case are drawn.
The attenuated flux inside the sample is also drawn.
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.
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.
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.
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.
Authors:János Lazányi, J. Loch, and I. Jászberényi
Current concerns about
soil and water quality deterioration, limited possibility of fossil fuels, loss
of biodiversity, and in general the viability of rural communities urge to work
out methods of sustainable agriculture in the Nyírség region of Hungary. Sustainable
agriculture seeks solutions for environmental, economic and agricultural
problems at the same time. The aim is to develop new production methods which
provide the protection of nature. In sustainable agricultural systems the
management of organic matters and, more widely, the whole nutrient management
are based on the total self-sufficiency of the farm. The entire cycle of
organic matter production and decomposition takes place within the farm
boundaries and makes the farm an actual biological system. The rate of
metabolism and the organic matter cycle are characteristic features of each
farm and define their activity for a long time. Present investigation
conducted in Westsik's crop rotation experiment has found a highly significant
correlation between organic nitrogen extracted by 0.01
solution and potato yield. It has shown that soil organic nitrogen extracted by
solution is a reliable indicator of nitrogen
available for mineralization during the growing season. When precise nitrogen
fertilizer recommendations are required, the method can supply additional
information for environmentally friendly, sustainable agriculture.