763 research outputs found
Some Basic Aspects of the Triple Decomposition of the Relative Motion near a Point
The triple decomposition of the relative motion near a point (TDM) ā based on the extraction of a so-called āeffectiveā pure shearing motion ā has been recently proposed by the present author. The relative motion near a point has been decomposed through the analysis of a āfrozenā flow field at a given instant in time. This approach has been motivated by the fact that vorticity cannot distinguish between pure shearing motions and the actual swirling motion of a vortex. The TDM results in two additive vorticity parts and two additive strainrate parts of distinct nature: the shear component associated with a pure shearing motion and the residual one. Some basic aspects of this novel decomposition technique are treated in the present paper. These aspects include: pure shearing motion and shearing elements in 3D, orbital compactness vs. arbitrary axial strain of a vortex, the interpretation of residual vorticity and the concept of residual circulation (i.e. a surface quadrature of the residual vorticity) for the description of vortex strength, and qualitative comparison of the TDM vorticity outcome with other known vorticity-decomposition techniques
GS-trapezoids in GS-quasigroups
In this paper the concept of a GS-trapezoid in a GS-quasigroup is defined and some characterizations of that are proved and geometrical representation of the properties of the quaternary relation GST in the GS-quasigroup is given
Metrical relationships in a standard triangle in an isotropic plane
Each allowable triangle of an isotropic plane can be set in a
standard position, in which it is possible to prove geometric properties analytically in a simplified and easier way by means of
the algebraic theory developed in this paper
DGS-trapezoids in GS-quasigroups
The concept of the DGS-trapezoid is defined and investigated in any GS-quasigroup and geometrical interpretation in the GS-quasigroup is also given. The connection of this concept with GS-trapezoids in the general GS-quasigroup is obtained
GS-deltoids in GS-quasigroups
A "geometric\u27\u27 concept of the GS-deltoid is introduced and investigated in the general GS-quasigroup and geometrical interpretation in the GS-quasigroup is given. The connection of GS-deltoids with parallelograms, GS-trapezoids, DGS-trapezoids and affine regular pentagons in the general GS-quasigroup is obtained
Stammler\u27s circles, Stammler\u27s triangle and Morley\u27s triangle of a given triangle
By means of complex coordinates shorter proofs of the results of L. Stammler [1], [2] will be given, plus several statements connected with them
Conforming finite element methods for the clamped plate problem
Finite element methods for solving biharmonic boundary value problems are considered. The particular problem discussed is that of a clamped thin plate. This problem is reformulated in a weak, form in the Sobolev space Techniques for setting up conforming trial
Functions are utilized in a Galerkin technique to produce finite element solutions. The shortcomings of various trial function formulations are discussed, and a macroāelement approach to local mesh refinement using rectangular elements is given
The influence of air pollution on the content of 3.4-benzpyrene in nonrefined oil obtained from sunflower seeds grown in differently polluted areas
Postavljena je pretpostavka da je zagaÄenost zraka jedan od bitnih elemenata koji uslovljuju kontaminaciju biljnih ulja. OdreÄivan je sadržaj 3,4-benzpirena u sirovom suncokretovom ulju, ekstrahiranom iz sjemena suncokreta, uzgajanog na razliÄito kontaminiranim podruÄjima, kao i u uzorcima zemlje, uzetih sa zasijanih povrÅ”ina. IskljuÄeni su moguÄe utjecaji u periodu sazrijevanja sjemena (žetva, transport, skladiÅ”tenje) pa do finalne industrijske prerade. Uzorci sjemena su ruÄno sabrani i laboratorijskom tehnikom prireÄeni uzorci ulja. NaÄene koliÄine 3,4-benzpirena u ulju, u koliÄinama od 0,4-40,5 Āµg/kg ulja, pokazuju direktnu ovisnost o intenzitetu zagaÄivanja zraka. Relativno visoki sadržaj 3,4-benzpirena u uzorcima zemlje (29,3-900,0 Āµg/kg zemlje) ukazuju na veliku rezistentnost i moguÄnost akumulacije ove karcinogene supstance.It is supposed that air pollution is one of crucial factors in contamination of vegetable oils. The content of 3,4-benzpyrene was determined in nonrefined oil, obtained from sunflower seeds which were grown in areas with varying degree of pollution, and in the samples of soil taken from the same areas. Possible influences during the ripening of the seed (harvest, transport, storage) until the final industrial processing were excluded. Seed samples were hand collected and oil samples prepared under laboratory conditions. The amount of 3,4-benzpyrene in oil ranges from 0.4-40,5 Āµg/kg oil and shows direct relationship with the intensity of air pollution. A relatively high content of 3,4-benzpyrene in soil samples (29.3-900.0 Āµg/kg soil) points at a high resistance and possibility of accumulation of this carcinogenic substance
Amperometric separation-free immunosensor for real-time environmental monitoring
Immunoanalytical techniques have found widespread use due to the characteristics of specificity and wide applicability for many analytes, from large polymer antigens, to simple haptens, and even single atoms. Electrochemical sensors offer benefits of technical simplicity, speed and convenience via direct transduction to electronic equipment. Together, these two systems offer the possibility of a convenient, ubiquitous assay technique with high selectivity. However, they are still not widely used, mainly due to the complexity of the associated immunoassay methodologies. A separation-free immunoanalytical technique is described here, which has allowed for the analysis of atrazine in real time and in both quasi-equilibrium and stirred batch configurations. It illustrated that determinations as low as 0.13 muM (28 ppb) could be made using equilibrium incubation with an analytical range of 0.1-10 muM. Measurements could be made between 1 and 10 mM within several minutes using a real-time, stirred batch method. This system offers the potential for fast, simple, cost-effective biosensors for the analysis of many substances of environmental, biomedical and pharmaceutical concern. (C) 2001 Elsevier Science B.V. All rights reserved
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