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Content available remote Thermosolutal instability of Walters' rotating fluid (Model B') in porous medium
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The thermosolutal instability of Walters' (Model B') fluid in porous medium is considered in the presence of uniform vertical rotation. For the case of stationary convection, the stable solute gradient and rotation have stabilizing effects on the system, whereas the medium permeability has a destabilizing (or stabilizing) effect on the system under certain conditions. The dispersion relation is also analysed numerically. It has also been shown that as rotation parameter increases, the stabilizing range of medium also increases. The kinematic viscoelasticity has no effect on the stationary convection. The stable solute gradient, rotation, porosity and kinematic viscoelasticity introduce oscillatory modes in the system, which did not occur in their absence. The sufficient conditions for the non-existance of overstability are also obtained.
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Introduction: Mobility of spine in persons with different types of idiopathic scoliosis hasn’t been estimate. The aim of this study was to state the influence of scoliosis on a range of rotation of trunk and pelvis in adolescent girls with idiopathic scoliosis (AIS). Methods: 59 AIS girls at the age of 10-18 participated in the study. Right thoracic curve or left lumbar curve at spine radiography were the criteria for further measurements. Four groups including girls with different types of scoliosis were formed. Measurements were made in upright standing position The special designed prototype axial rotation tester with flip computer system was used to assess the range of rotation. The shoulder girdle with upper p of the trunk or the pelvis were fixed during tested rotation motions. The number and order motions were precisely determined in the study. 30 healthy girls without scoliosis were test as the control group. ANOVA test and T-test were used for statistical analyzes. Results: There are significant differences between the girls with double curve scoliosis with dominant right thoracic curve, the girls with single or double curve scoliosis with dominant left lumbar curve and the control group. Limited rotation of trunk and pelvis in horizontal plane were observed in the girls with double curve scoliosis with the dominant right thoracic curve. Increased rotation of pelvis in girls with single or double curve scoliosis with dominant left lumbar curve was found. Conclusions: A range of rotation of trunk and pelvis in girls with idiopathic scoliosis depends on a type of scoliosis, especially on location of dominant curve of scoliosis. A dominant right thoracic curve causes limitation of a range of rotation of trunk or pelvis and provokes asymmetries between a range of left and right rotation. A dominant left lumbar curve is conductive to increase a range of rotation of pelvis and provokes asymmetries between a range of left and right rotation.
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Temperature H NMR spectra of the title compound were measured and inter-preted in terms of slow rotation about the bond between piperidine ring and benzoyl sub-stituent. Barrier to this rotation was calculated to be Ea = 59 kJ/mol and log(A) = - 14.2.
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Lately, Biometrics has employed the use of fingerprints to identify individuals. Out of the commonly used techniques, fingerprint authentication till date, remains the most reliable. The bulk of research that has focused on fingerprint authentication, has however, neglected the issues that arise with fingerprints resulting to incorrect orientation identification. This is because it is assumed and often times wrongly, that the direction of the fingerprint will align with the stored fingerprint image. This singular issue poses tension in fingerprint matching, which only a negligible number of techniques have considered. As computers and mobile devices adopt fingerprint recognition as a way to authenticate user, this apparent tension gains more popularity, becoming an integral research area which must be addressed.
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The aim of this study was to compare muscle strength at 90° hip and knee flexion as measured in three different positions and to investigate whether an internal or external deficit in the range of rotation in the hip joint affects flexor muscle strength. Methods: We measured the peak muscle torque of rotation in the hip joint, using isometric torquemeter, and hip ROM in healthy participants N = 40, aged 21.6 ± 1.9, in three different measurement positions. We tested for differences between the positions, and for the potential influence of participant’s sex and ROM asymmetry. Results: The measured peak muscle torque was affected not only by sex and the value of hip flexion affect, but also by the position in which it is measured. Subjects with restricted external rotation of the hip joint (CERD) had significantly higher flexor peak muscle torque compared to subjects with restricted internal rotation (CIRD), in all but the supine position. For CERD, the results were: Supine (SuP) 1.02 ± 0.26; Sitting (StP) 1.32 ± 0.58; Standing (SP) 1.53 ± 0.47; and for CIRD, the results were: Supine (SuP) 1.05 ± 0.17; Sitting (StP) 1.05 ± 0.40; Standing (SP) 1.47 ± 0.53. Conclusions: Overall, measurement position and passive ROM significantly influence the peak muscle torque in isometric conditions. Moreover, an imbalance in thigh rotation movement significantly determines the magnitude of muscle torque of the hip flexion movement. Individuals with increased internal-toexternal rotation achieved significantly higher values for flexor muscle torque force moments. Overall, these findings are of importance for interpreting or comparing any reported values for muscle torque force moments.
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Content available remote Ellipse Invariant Algorithm for Texture Classification
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The classification of texture images, especially those with spatial rotation and region shift, is a challenge and important problem in image analysis and classification. This paper proposes a novel algorithm design, an ellipse invariant algorithm, to improve the capability of texture classification for spatial rotation and region shift. The principle of an ellipse invariant algorithm is to use a minimum ellipse to enclose specific representative pixels extracted by the subtracting clustering method. After translating the coordinates, the ellipse in the rotated texture would be formulated as the ellipse in original texture. Also in this paper a hybrid texture filter is proposed. In the hybrid texture filter the scheme of texture feature extraction include Gabor wavelet, neighboring grey level dependence matrix and the ellipse invariant algorithm. Support vector machines (SVMs) are introduced as the classifier. The proposed hybrid texture filter can classify both the stochastic textures and structural textures. Experimental results reveal that this proposed algorithm outperforms existing design algorithms.
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A layer of a couple-stress fluid heated from below in a porous medium is considered to include the effect of uniform rotation. For the case of stationary convection, the couple stress may hasten the onset of convection in the presence of rotation while in the absence of rotation, it always postpones the onset of convection. For the case of stationary convection, rotation postpones the onset of convection. Graphs have been plotted by giving numerical values to the parameters, to depict the stability characteristics. Rotation is found to introduce oscillatory modes in the system, which were non-existent in its absence. A sufficient condition for the non-existence of overstability is obtained.
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The thermosolutal instability of Walters' (model B') elastico-viscous rotating fluid in a porous medium is considered in the presence of a uniform rotation, suspended particles and variable gravity field. the stable solute gradient, rotation, gravity field, suspended particles and viscoelasticity introduce oscillatory modes. For the stationary convection, the stable gradient and rotation have stabilizing effects and suspended particles are found to have destabilizing effect on the system, whereas the medium permeability has destabilizing or stabilizing efect on the system under certain conditions. The effects of stable solute gradient, rotation, suspended particles, medium permeability have also been shown graphically.
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The paper deals with modelling problems of periodic stratified composites with micropolar elastic components. By using the linear theory of micropolar elasticity and the homogenization method with microlocal parameters, a homogenized model accounting certain local effects of stresses and coupled stresses is derived. From the obtained model, systems of equations for the "first" and the "second" plane state of strain of the layered composites are presented.
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Praca dotyczy zagadnień modelowania periodycznych warstwowych kompozytów o składnikach mikropolarnych. Wykorzystując liniową teorię mikopolarnej sprężystości i metodę homogenizacji z parametrami mikrolokalnymi wyprowadzono model homogenizowany uwzględniający pewne efekty lokalne w naprężeniach i naprężeniach momentowych. Z otrzymanego modelu otrzymano układy równań dla" pierwszego" i "drugiego" płaskiego stanu odkształcenia dla periodycznie warstwowych kompozytów mikropolarnych.
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This work investigates rotational effects on propagation and reflection of waves at the free surface of a micropolar fibre-reinforced medium with voids under magnetic fields. When the P-wave is incident on the free surface, there exist four coupled reflected plane waves traveling in the medium; quasi-longitudinal displacement (qLD) wave, quasi-transverse displacement (qTD) wave, quasi-transverse microrotational (qTM) wave and a wave due to voids. Normal mode analysis is adopted in concomitant with Snell’s laws, and appropriate boundary conditions in determination of the solution. Amplitude ratios which correspond to reflected waves in vertical and horizontal components are presented analytically and graphically.
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The purpose of this study was to determine whether three different measurement position yield divergent results in ROM using a goniometer, and how is it affected by anthropometrical factors. Methods: We measured the range of rotation in the hip joint in healthy participants aged 21.6 ± 1.88, seeking to determine how the distribution of internal vs. external rotation (RI) within the total range of mobility (TR) was influenced by the measurement position used, the gender of the participant, and the dominant lower limb. Results: We found that not only gender and limb dominance, but also the body position in which hip joint’s range of motion is measured significantly affects the values of TR and RI. We found that TR achieves the highest values in the prone position – PrP (males: 95.35 ± 12.44 and 93.15 ± 12.49; females: 103.75 ± 14.87 and 106.25 ± 15.56) and the lowest values in supine position – SuP (male: 62.65 ± 8.51 and 57.85 ± 9.60; female: 59.5 ± 12.27 and 55.85 ± 8.54). The analysis shows that CERD occurs <0.42 RI in females (PrP) and <0.88 RI in men (PrP and sitting position – StP), and CIRD >1.72 RI in women (StP), and >2.08 RI in men (PrP). Conclusions: Due to the similarities between asymmetry of internal/external rotation in the hip joint and asymmetry in the rotation of the shoulder found in Glenohumeral Internal Rotation Deficit (GIRD), we propose the concepts of Coxal Internal Rotation Deficit (CIRD) and Coxal External Rotation Deficit (CERD) as tools to indicate the possibility for injury to the hip joint, and propose threshold rotation index values serving as indicators of these deficits.
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The study is aimed at analysing thermal convection in a compressible couple stress fluid in a porous medium in the presence of rotation and magnetic field. After linearizing the relevant equations, the perturbation equations are analysed in terms of normal modes. A dispersion relation governing the effects of rotation, magnetic field, couple stress parameter and medium permeability have been examined. For a stationary convection, the rotation postpones the onset of convection in a couple stress fluid heated from below in a porous medium in the presence of a magnetic field. Whereas, the magnetic field and couple stress postpones and hastens the onset of convection in the presence of rotation and the medium permeability hastens and postpones the onset of convection with conditions on Taylor number. Further the oscillatory modes are introduced due to the presence of rotation and the magnetic field which were non-existent in their absence, and hence the principle of exchange stands valid. The sufficient conditions for nonexistence of over stability are also obtained.
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Soil is a solid particle that covers the surface of the earth. Soil can be classified based on its color because the color indicates the nature and condition of the soil. CNN works well for image classification, but it requires large amounts of data. Augmentation is a technique to increase the amount of training data with various transformation techniques to the existing data. Rotation and Gamma Correction can be used simply as an augmentation technique and can reproduce an image with as many image variations as desired from the original image. CNN architecture has a convolution layer and Dense block has dense layers. The addition of Dense blocks to CNN aims to overcome underfitting and overfitting problems. This study proposes a combination of Augmentation and classification. In augmentation, a combination of rotation and Gamma correction techniques is used to reproduce image data. The CNN-Dense block is applied for classification. The soil image classification is grouped based on 5 labels black soil, cinder soil, laterite soil, peat soil, and yellow soil. The performances of the proposed method provide excellent results, where accuracy, precision, recall, and F1-Score performances are above 90%. It can be concluded that the combination of rotation and Gamma Correction as augmentation techniques and CNN-Dense blocks is powerful for use in soil image classification.
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Content available remote Watching steps of a grand tour implementation
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Bartkowiak and Szustalewicz, 1997 (B&Sz), have proposed an implementation of the grand tour algorithm designed specially to detect outliers in multivariate data. The algorithm work by performing a sequence of rotations and projections onto a specific 2D-plane (Π proj). This is equivalent to perform a series of rotations yielding transformed coordinates of the data: X(tr) = XA, with A being the rotation matrix, while X and X,sup>(tr) denote the data matrices before and after the rotation appropriately. A superimposed concentration ellipse indicates the outstanding points. We complement the paper of B&Sz by considering some details and variants of the implementation of the grand tour algorithm. In particular we watch the trajectories of the projected points. Our concern is the denseness of the watched projctions. We look at the trajectories of the projected point visible in the Π proj plane and the frequencies of thier appearing in various sectors of that plane. In the Appendix we present the derivation of the formula for the rotation matrix A employed in each step of the algorithm for obtaining the transformed data coordinates.
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Content available remote Stability of a Viscoelastic Shaft in Fluid-Film
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An analysis of dynamic stability of a rotating system consisting of a flexible shaft and two hydrodynamic bearings is presented with special attention paid to the interaction of two instability sources - the internal friction in the shaft material and the fluid-film action in the bearings. Stability is determined and the critical speed of rotation is calculated from the eigenvalue analysis of the rotor system locally linearized around a nontrivial speed- and load-dependent static equilibrium. Journals of the bearings are assumed to be lumped-mass elements performing plane motion, so that the shaft and bearing equations are coupled by the shaft end shear force. A single-mode Galerkin's discretization is performed leading to an 8-dimensional problem incorporating 14 geometric and physical system parameters. It is shown that generally shaft and bearing compliances destabilize the system, although it is also possible that a flexible shaft in fluid-film bearings is more stable than in rigid supports. An interesting effect is related to the double Hopf bifurcation which consists in simultaneous loss of stability by two eigenvalues. It appears for certain parameter values and is expected to lead to complicated postcritical behaviour.
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W pracy przedstawiono analizę stateczności dynamicznej układu wirującego złożonego z odkształconego wału i podpierających ten wał łożysk hydrodynamicznych. Celem pracy jest zbadanie interakcji dwóch różnych fizycznych przyczyn niestateczności - tarcia wewnętrznego w wirującym podatnym wale i oddziaływania dynamicznego filmu olejowego w łożyskach. Krytyczną prędkość wirowania układu na granicy obszaru niestateczności typu "flatter" wyznaczono rozwiązując zagadnienie własne początkowe układu wirnika lokalnie zlinearyzowanego wokół nietrywialnego położenia równowagi, zależnego od obciążenia poprzecznego wału. Założono, że czopy łożysk ślizgowych są elementami sztywnymi poruszającymi się ruchem płaskim, co oznacza, że równania wału i czopów są sprzężone poprzez siłę poprzeczną w końcowych przekrojach wału. Zastosowano jednomodalną dyskretryzację Galerkina dla wału, co doprowadziło do układu ośmiu równań zwyczajnych z czternastoma parametrami fizycznymi i geometrycznymi. Pokazano, że podatność wału i łożysk ogólnie destabilizuje układ, chociaż jest również możliwe, że odkształcony wał w łożyskach ślizgowych jest bardziej stateczny niż taki samk wał na podporach sztywnych. Występuje interesujący efekt związany z podwójną bifurkacją Hopfa, która polega na jednoczesnym przekroczeniu granicy stateczności przez dwie różne wartości własne układu. Zjawisko to występuje dla pewnych wartości parametrów i może prowadzić do skomplikowanych pokrytycznych zachowań dynamicznych układu.
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We demonstrate that the idea of symmetropy can be used for quantification of earthquake patterns. The symmetropy can be considered as a measure of asymmetry. A pattern is richer in asymmetry when the symmetropy is smaller. The specific results of its applications are obtained as follows. In a discrete model of a seismic source with self-organized criticality, the spatial patterns of earthquakes during critical states and subcritical states are distinguished by the behaviour of the symmetropy: subcritical patterns show that the symmetropy is approximately a constant but this has various values during critical states. The critical patterns show asymmetric property without any asymmetric force from the outside and without asymmetric intracellular rule. We show that the emergence of asymmetric patterns is a generic feature of dynamic ruptures in our model. Such a generic asymmetry results from the model which is an inherently discrete system consisting of finite -sized cells. These cells may represent geometrical disordered fault zones. We further discuss rotational motions that generate seismic rotational waves. In micro-morphic continuum theory, such rotations are attributed to dynamic ruptures in dis-ordered systems. We note that the concept of disorder in this theory is expressed by a set of finite-sized microstructures and is consistent with the concept of disorder modelled in the present study. Thus, we suggest that the spatially asymmetric patterns of earthquakes might be related to the rotational motions, because both come from dynamic limit.
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Content available remote An Edge-based Image Copy Detection Scheme
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This paper presents a novel scheme to detect copied versions of digital images, particularly in an Internet environment based on edge information of images. The edge information is used to generate the signature set for a corresponding image. The edge-based signature sets are then used to compute the distortions between query images and test images, from among which a user wants to find copies. Experimental results confirm that the proposed scheme not only withstands various modifications of an original image but also offers good detection performance in dealing with various rotations, shifting of 17.5% of the width or height of an image, and cutting out up to 45% of the area of an image, which previous research work has found difficult to detect. Therefore, our proposed scheme could be very helpful in detecting copies of digital images transmitted in an Internet environment.
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W pracy poszukiwano zależności po między dawką promieniowania mikrofalowego a wytrzymałością bulwy ziemniaka na obciążenia statyczne mierzone siłą przebicia skórki bulwy ziemniaka na granicy wytrzymałości biologicznej. Do badań przyjęto dwie odmiany ziemniaka: Gracja i Ibis. Bulwy ziemniaka podzielono na trzy frakcje wagowe: poniżej 40 g, od 40 do 70 g i od 70 do 110 g. Każda frakcja reprezentowana była przez 5 bulw poddanych stymulacji mikrofalowej oraz 10 bulw stanowiących próbę kontrolną nie poddanych działaniu pola mikrofalowego. W pierwszej części doświadczenia pojedynczą bulwę umieszczano w polu elektromagnetycznym o częstotliwości 2,45 GHz na czas 5 s. Zmianie ulegała moc promieniowania w zakresie od 100 do 1000 W. W drugiej części doświadczenia przy tej samej częstotliwości zmianie ulegał czas oddziaływania promieniowania mikrofalowego w zakresie od 2 do 20 s a wartością stałą była moc promieniowania - 270 W. Następnie bulwy poddane stymulacji mikrofalowej oraz bulwy stanowiące próbę kontrolną obciążano przy użyciu penetrometru statyczno- sprężynowego. Wyniki doświadczenia miały dać odpowiedź na pytanie - czy promieniowanie mikrofalowe w przyjętych czasach ekspozycji i dawkach, mając stymulujący wpływ na procesy fizjologiczne bulwy oddziaływuje na jej strukturę wewnętrzną zmieniając odporność na mechaniczne uszkodzenia? Analiza statystyczna nie wykazała istotnych różnic pomiędzy próbą kontrolną a próbami poddanymi działaniu promieniowania mikrofalowego w zakresie przyjętych do badań czasów ekspozycji i dawek promieniowania. Nie stwierdzono zatem wpływu promieniowania mikrofalowego na odporność bulw ziemniaka na obciążenia statyczne.
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The purpose of the studies was to find the relation between a microwave radiation dose and resistance of potato bulb to static load measured by a force of punching potato bulb skin at the biological resistance limit. The tests were performed using two potato variations: Gracja and Ibis. Potato bulbs were divided into three weight fractions: less than 40 g, from 40 to 70 g and from 70 to 110 g. Each fraction was represented by 5 bulbs put to microwave stimulation and 10 bulbs served as control sample not put to microwave field activity. In the first part of the experiment a single bulb was placed in the electromagnetic field with a frequency of 2,45 GHz for 5 sec. Radiation power was changed from 100 to 1000 W. In the second part of the experiment microwave radiation duration was changed from 2 to 20 sec with the same frequency and radiation power of 270 W was kept unchanged. Then bulbs were put to microwave stimulation and bulb control samples were loaded with a static-spring penetrometer. Results of the experiment were to answer the question - does the microwave radiation within the adopted exposure and dose limits, having a stimulating influence on the physiological processes of the bulb act on its internal structure by changing resistance to mechanical damages? The statistical analysis did not show any significant differences between the control sample and the samples exposed to microwave radiation within the exposure time and radiation dose limits adopted for tests. No influence of microwave radiation on potato bulb resistance to static load was shown.
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The present analysis is made to investigate the effects of Hall current on the free convection flow of an incompressible, viscous fluid through a porous medium in a rotating system past an infinite vertical porous plate in the presence of a heat sink and a transversely applied uniform magnetic field. Solutions of velocity and temperature fields are obtained using the perturbation technique. Expressions for the skin motion and heat transfer are also derived. It is found that the increase in the magnetic parameter (M) decreases both the primary skin friction [...] and secondary skin friction [...] while an increase in the Hall parameter (m) decreases [...] but increases [...].
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Content available remote Rotation of PRODAN in excited state
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Instant spectra and anisotropy kinetics of PRODAN luminescence in different ranges of spectra has been studied upon excitation by picosecond pulses. Instant spectra of luminescence reveal time dependent Stokes shift having intermolecular nature as its characteristic time correlates with dielectric relaxation time of solvent. The mean Brownian rotation time for the curves obtained shows complex character of spectral dependence with maximum ~39 ns near maximum of luminescence intensity and drops down to 15 ns on the edges of the spectrum. An explanation is based on a treatment of intermolecular energy conversion into thermal movement of molecules during relaxation in excited state. Calculations using hydrodynamic model show “stick” boundary conditions for solutes: rotational volumes correspond to solute together with molecules of the first coordinative sphere filled by solvent.
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