5,792 research outputs found
Benchmarking for process control with applications in the hot strip finishing steel mill
This paper describes how new benchmarking concepts can be applied to different aspects of process control performance assessment
Multi-variable LQG optimal control - restricted structure control for benchmarking and tuning
The paper introduces the benchmarking of multivarialbe systems using an offline optimal LQG approach
Quantitative foraminiferal and palynomorph biostratigraphy of the Paleogene in the southwestern Barents Sea
The stratigraphic distribution of both foraminifera and dinoflagellate cysts is recorded from the
Paleocene to Eocene Torsk Formation in 12 petroleum exploration wells drilled in the southwestern
Barents Sea. The foraminiferal assemblages are wholly agglutinated, and are referred to outer shelf to
middle bathyal environments. A quantitative analysis of biostratigraphic events, mainly last
occurrences (first downhole occurrences), is performed by means of the Ranking and Scaling (RASC)
program. This procedure combined with conventional stratigraphic treatment has enabled us to
establish the most likely order of microfossil events, and to propose a new quantitative zonal scheme
for the southwestern Barents Sea.
In the studied wells the following six zones and subzones are distinguished (in ascending order):
BSP 1, Psmmosphaera fusca â Hyperammina rugosa, late early to early late Paleocene; BSP 2,
Spiroplectammina spectabilis early late Paleocene; BSP 3A, Reticulophragmium pauperum, middle late
Paleocene; BSP 3B, Haplophragmoides aff. eggeri, latest Paleocene; BSP 4, Spiroplectammina navarroana,
earliest Eocene; BSP 5, Reticulophragmium amplectens, early to middle Eocene. Owing to the
occurrence of cosmopolitan deep-water agglutinated foraminifera, the new zonal scheme compares
well with previous zonations developed for the Paleogene of the mid-Norwegian shelf, the North Sea
and Labrador Shelf
Convergence of Hill's method for nonselfadjoint operators
By the introduction of a generalized Evans function defined by an appropriate 2- modified Fredholm determinant, we give a simple proof of convergence in location and multiplicity of Hill's method for numerical approximation of spectra of periodic-coefficient ordinary differential operators. Our results apply to operators of nondegenerate type under the condition that the principal coefficient matrix be symmetric positive definite (automatically satisfied in the scalar case). Notably, this includes a large class of non-self-adjoint operators which previously had not been treated in a simple way. The case of general coefficients depends on an interesting operator-theoretic question regarding properties of Toeplitz matrice
Group a streptococcal serotypes isolated from healthy schoolchildren in iran
Serotypes of group A streptococci are still a major cause of pharyngitis and some post-infectious sequelae such as rheumatic fever. As part of the worldwide effort to clarify the epidemiological pattern of group A streptococci in different countries, the present study was conducted to assess the prevalence of Streptococcus pyogenes serotypes in Iran. A total of 1588 throat swabs were taken from healthy school children in the city of Gorgan during February and March 1999. Of those isolates, 175 resulted positive for group A streptococci. The distribution pattern was similar for girls and boys, with 10.8 and 11.2, respectively. Urban school children showed a higher rate of colonization compared to those in rural areas. Serotyping was performed on 65 of the positive isolates using standard techniques, and only 21 (32) were M-type isolates. Their profiles fell into four types with M1 predominating, which could reflect the presence of rheumatic fever in the region. However, when isolates were challenged for T-antigen types, nearly all were positive (94). The pattern of T types was diverse (18 types), with the most common T types being T1 (26), TB3264 (15), TB\1-19 & B\25\1-19 (9.2) and T2 & 2\28 (7.7). When isolates were tested for opacity factor, only 23 (35) were positive while 34 (52) responded to the serum opacity reaction test. Although the number of isolates in this study was not sufficient to make any epidemiological conclusions, the scarcity of serotyping studies in Iran could render these data useful for future attempts to develop a streptococcal vaccine
Modulational Instability in Equations of KdV Type
It is a matter of experience that nonlinear waves in dispersive media,
propagating primarily in one direction, may appear periodic in small space and
time scales, but their characteristics --- amplitude, phase, wave number, etc.
--- slowly vary in large space and time scales. In the 1970's, Whitham
developed an asymptotic (WKB) method to study the effects of small
"modulations" on nonlinear periodic wave trains. Since then, there has been a
great deal of work aiming at rigorously justifying the predictions from
Whitham's formal theory. We discuss recent advances in the mathematical
understanding of the dynamics, in particular, the instability of slowly
modulated wave trains for nonlinear dispersive equations of KdV type.Comment: 40 pages. To appear in upcoming title in Lecture Notes in Physic
On homomorphism of fuzzy multigroups
In this paper, the homomorphism of fuzzy multigroups is briefly delineated following [2] and their corresponding isomorphism theorems are considered
The Underwater Photic Environment of a Small Arctic Lake
The underwater light field in a small arctic lake on Victoria Island, Northwest Territories, was examined. Downward radiance was found to be bimodal, with transmission peaks at 480 and 640 nanometres (nm, or .000000001 m). Upward radiance was similar near the surface, with peaks at 480 and 620 nm, but became unimodal with depth and shifted to 580 nm near the bottom. Diurnal variation in the underwater downward and upward irradiance of PAR (photosynthetically active radiation) was approximately two orders of magnitude. The spectral quality of light transmission also changed over this 24 hour period. Unimodal transmission of red light occurred in the early morning (1:00 and 5:00) and late evening (22:00), while bimodal transmission of blue-green and red light was observed during the day (9:00-17:30). Kd(Zm), the vertical attenuation coefficient for downward irradiance at the midpoint of the euphotic zone, was relatively insensitive to changes in solar elevation. Diurnal variation in the reflectance of PAR differed from the predicted by previous simulation models, while the inverse relationship between reflectance and the absorption coefficient was in agreement with these same models. Gilvin, humic material-dissolved iron complexes, algal fucoxanthin, chlorophyll a and tripton all contribute to the attenuation of light and are responsible for the unique underwater spectral transmission in Keyhole Lake.
Heterogeneity of wheat endosperm proteolipids (CM proteins)
Proteins extracted with CHCl3-MeOH from wheat endosperm have been fractionated by Sephadex G-100 and the 15 000â20 000 MW range fraction, designated CM protein, has been examined by combined electrofocusing (pH range 5â8) and electrophoresis (pH 3.2) and the heterogeneity of the electrophoretic components has been ascertained. It has been shown by joint mapping and by sequential extraction that CM proteins are extracted by 70% EtOH but not by H2O, although they can be made water-soluble after dialysis against an acid buffer, pH 3.2, 3 M urea, without losing their solubility in CHCl3-MeOH mixtures. It is concluded that CM proteins fit the definition of a FolchâLees proteolipid. The Triticum aestivum (genomes ABD) map can be reconstructed by mixing T. durum (AB) and Aegilops squarrosa (D). The low intragenomic variability of CM protein is confirmed
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