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1
Content available remote Zarządzanie zasobami magazynowymi – stanem magazynu
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PL
Sztuka zarządzania magazynem to z jednej strony dążenie do maksymalizacji wykorzystania fizycznej struktury magazynu, a z drugiej – optymalizacja składowanego tam zapasu. W artykule opublikowanym w numerze 3/2013 czasopisma TWiM nasza uwaga skupiała się na tym, jak do danego nam magazynu „wcisnąć” jak najwięcej towaru, tak by najefektywniej wykorzystać jego fizyczną wielkość/strukturę.
EN
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.
PL
Niniejsza praca dotyczy działania podwodnych tam poprzecznych usytuowanych pod ostrym kątem w stosunku do nurtu rzeki. Za taką konstrukcją powstaje spiralny nurt ze spiralną strukturą, co z powodu wysokich wartości prędkości chwilowej wzdłuż konstrukcji i rotacji przyczynia się do znaczącego wzrostu przepływu masy w cieku, podmywania strefy brze-gowej, przypuszczalnie dodatkowego przyciągania tlenu atmosferycznego do cieku oraz prawie całkowitego mieszania ścieków zrzucanych za tamą z nurtem rzeki.
EN
This paper considers the operation of low submerged (flooded) groins oriented by the sharp angle relatively to the incoming flow. Helical flow with a spiral structure arise behind such construction which, due to high values of transitional velocity directed along the construction and rotating, providing a significant enhancement of mass transfer in the stream, washing of the riverside zone, and supposing additional attraction of atmospheric oxygen into the stream and also almost complete initial mixing of wastewater discharged behind the groin with the river flow.
EN
The effect of magnetic field dependent viscosity on ferrofluid flow due to a rotating disk is studied in the presence of a stationary magnetic field. The results for velocity profiles for various values of MFD viscosity parameter are shown graphically. These results are compared with the ordinary case when the applied magnetic field is absent. Besides, the shear stress on the wall of the disk and its surface is calculated numerically.
EN
In this paper, a two-dimensional problem of thermoviscoelasticity with two relaxation times when the entire medium rotates with a uniform angular velocity is studied. The normal mode analysis is used to obtain the exact expressions for the temperature, displacement and thermal stress components. The resulting formulation is applied to the case of a thick plate subjected to a time-dependent heat source on each face. Numerical results are given and illustrated graphically. Comparisons are made with the results predicted by the coupled theory and with the theory of generalized thermoelasticity with two relaxation times in the absence of rotation and for different values of time.
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Content available remote Algorytmy do analizy składowych wektora prędkości
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W artykule przedstawiono algorytmy komputerowe zaprojektowane w celu analizy składowych płaskiego pola prędkości. Informacje o składowych wektora prędkości pochodzą z programu Dantec Dynamic Studio lub programu powstałego w Instytucie. Analizowane są wszystkie pliki z wybranego katalogu. Programy te generują płaskie pola prędkości wyznaczane przy pomocy anemometrii cyfrowej (Particle Image Velocimetry – PIV). W programie możemy analizować składowe wektora prędkości wzdłuż linie poziomej i pionowej. Możemy zapisać pliki w celu narysowania trójwymiarowego pola wybranej składowej wektora prędkości lub zmiany składowych w czasie. Istnieje możliwość wyznaczenia sumy, wartości średniej, odchylenia standardowego, czy rotacji wektora prędkości.
EN
Algorithms used to analyze velocity of vector components are presented in the paper. Information about velocity components come from Dantec Dynamic Studio Program or program designed by the authors. All of the files from the selected catalogue are analyzed. As a result 2D velocity fields are generated from the PIV data. The authored computer program allows to analyze velocity vector components along horizontal and vertical lines. Files saved are used to draw a three dimensional velocity fields or to visualize variations of the components of velocity vectors in time. Statistical parameters such as: sum, mean, standard deviation or rotation of the velocity vector are routinely computed.
EN
Rotations are an integral part of various computational techniques and mechanics. The objective in this paper is twofold: first to have a classical insight into the history of quaternions, a problem that Hamilton faced for over a decade and secondly to look at into its applications from computer graphics perspective. Thorough revision of quaternion algebra and its use case as a rotation operator has been presented. A quaternion simulation algorithm has been written and practiced to generate simulation results. Results show that though quaternions supersede Euler angles technically but are tricky to use and control for e.g. when same quaternion is applied on a different vector axis, the particle is not able to reach its initial position and an incomplete rotation effect has been recorded and observed.
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Content available remote Torque of the shank rotating muscles in patients with knee joint injuries
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EN
The aim of the study was to evaluate the torque of the shank rotating muscles in patients with reconstructed anterior cruciate ligament (ACL) and rehabilitation accomplished in comparison with a control group. The study was carried out on the group of 187 males. For the purpose of the study a prototype testing device for the shank rotating muscles' torque under static conditions was used. The study was based on the measurement of maximal torque at selected angles (-30 degree, 0 degree, 45 degree) of the shank rotation as well as on the angle (30 degree, 60 degree, 90 degree) of flexion of the knee joint. The results obtained in the group with reconstructed anterior cruciate ligament (ACL) and rehabilitation accomplished were comparable to those the control group and mostly of no statistical significance. Lack of significant differences between the values of shank rotating muscles' torque achieved in an injured limb compared to an uninjured one may testify to an effective rehabilitation process. The results of the research can serve as a diagnostic tool for the rehabilitation process development.
EN
Thermal Instability (Benard’s Convection) in the presence of uniform rotation and uniform magnetic field (separately) is studied. Using the linearized stability theory and normal mode analyses the dispersion relation is obtained in each case. In the case of rotatory Benard’s stationary convection compressibility and rotation postpone the onset of convection whereas the couple-stress have duel character onset of convection depending on rotation parameter. While in the absence of rotation couple-stress always postpones the onset of convection. On the other hand, magnetic field on thermal instability problem on couple-stress fluid for stationary convection couple-stress parameter and magnetic field postpones the onset of convection. The effect of compressibility also postpones the onset of convection in both cases as rotation and magnetic field. Graphs have been plotted by giving numerical values to the parameters to depict the stationary characteristics. Further, the magnetic field and rotation are found to introduce oscillatory modes which were non-existent in their absence and then the principle of exchange of stability is valid. The sufficient conditions for non-existence of overstability are also obtained.
EN
In this paper, we investigate the effect of a vertical magnetic field on thermal instability of an Oldroydian visco-elastic rotating fluid in a porous medium. By applying the normal mode analysis method, the dispersion relation governing the effects of rotation, magnetic field and medium permeability is derived and solved analytically and numerically. For the case of stationary convection, the Oldroydian viscoelastic fluid behaves like an ordinary Newtonian fluid and it is observed that rotation has a stabilizing effect while the magnetic field and medium permeability have a stabilizing/destabilizing effect under certain conditions on thermal instability of the Oldroydian viscoelastic fluid in a porous medium. The oscillatory modes are introduced due to the presence of rotation, the magnetic field and gravity field. It is also observed that the ‘principle of exchange of stability’ is invalid in the presence of rotation and the magnetic field.
PL
Celem prowadzonych badań było określenie wpływu rotacji herbicydów na liczebność chwastów odpornych w monokulturze kukurydzy. W latach 2000-2004 prowadzono doświadczenie na plantacji kukurydzy, uprawianej od 1992 roku w monokulturze, którą corocznie odchwaszczano herbicydami triazynowymi. Na polu tym zidentyfikowano odporne na atrazynę Amaranthus retroflexus, Chenopodium album i Echinochloa crus-galli. W roku 2000 plantację podzielono na dwie części. Na jednej części nadal, corocznie stosowano herbicydy triazynowe, na drugiej zaś zmieniono dotychczas stosowane herbicydy na środki z grupy sulfonylomocznika. W roku 2004 obie części plantacji poddano ocenie stanu zachwaszczenia, z oznaczonych powierzchni pobrano próbki chwastów i metodą pomiaru fluorescencji określono liczebność osobników odpornych w poszczególnych zbiorowiskach. Uprawa kukurydzy w monokulturze oraz brak zmianowania herbicydów przyczyniły się do wystąpienia i rozwoju odporności biotypów Amaranthus retroflexus, Chenopodium album i Echinochloa crus-galli. Wprowadzenie rotacji herbicydów o różnym mechanizmie działania umożliwiło wzrost skuteczności zwalczania chwastów i ograniczyło liczebność osobników odpornych w populacji o około 8-15% w porównaniu do stanu z roku 2000.
EN
The aim of investigations was evaluation of herbicides rotation effect on variation of the number of resistant weed biotypes found in maize monoculture. Investigations were conducted on a maize field cultivated since 1992 as monoculture, where triazine herbicides were applied annually. In 2000 this field was divided into two blocks. On the first block application of triazine herbicides continued. On second block triazine herbicides were replaced by sulfonylurea herbicides. Using the fluorescence method on these fields the number of resistant weed biotypes was determined (Amaranthus retroflexus, Chenopodium album and Echinochloa crus-galli). After the four years the number of resistant biotypes was checked again. On the field, where triazine herbicides were applied, the increase of the number of resistant weeds was observed. Rotation of herbicides caused the decrease of the number of resistant weeds by 8-15% in comparison with the situation in 2000.
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Content available The tectonic evolution of Lake Eğirdir, West Turkey
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EN
Lake Eğirdir is one of the most important fresh-water lakes of Turkey. It has a tectonics-related origin. The area formed under a roughly N-S compressional tectonic regime during the Middle Miocene. The stresses caused slip faults west and east of Isparta Angle, and the lake formed at the junction of these faults. The area subsided between normal faults, thus creating the topographic condition required for a lake. The lacustrine sediments have fundamentally different lithologies. After the Late Miocene, central Anatolia started to move westwards, but western Anatolia moved in a SW direction along the South-western Anatolian Fault , which we suggest to have a left lateral slip, which caused that the Hoyran Basin moved t7 km towards the SW and rotated 40º counterclockwise relative to Lake Eğirdir.
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In this study, the steady laminar boundary layer flow of micropolar fluids over a wedge has been examined with the constant heat flux boundary condition on the wedge surface. The similarity variables found by Falkner and Skan are employed to reduce the streamwise-dependence in the coupled nonlinear boundary layer equations. Numerical solutions are presented for the heat transfer characteristics using the fourth-order Runge-Kutta numerical procedure with shooting method. The micro-rotation velocity and temperature distributions across the boundary layer are plotted with different wedge angles and compared with the corresponding flow problems for a Newtonian fluid.
EN
In this paper, the effects of rotation on a Jeffery nanofluid flow in a porous medium which is heated from below is studied. Darcy model is employed for porous medium and the Jeffrey fluid model is used as a base fluid. The Navier-Stokes equations of motion of fluid are modified under the influence of the Jeffrey parameter, naoparticles and rotation. The basic perturbation technique based on normal modes is applied to derive the dispersion relation for a Rayleigh number. The effects of the Taylor number, Jeffrey parameter, Lewis number, modified diffusivity ratio, nanoparticles Rayleigh number and medium porosity on the stationary convection of the physical system have been analyzed analytically and graphically. It is observed that the rotation parameter has a stabilising influence for both bottom/top-heavy configurations.
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Content available remote Human hip joint lubrication for permeable cartilage.
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EN
This paper shows numerical calculations of the friction forces in spherical and other curvilinear orthogonal coordinates for hydrodynamic unsymmetrical synovial non-Newtonian fluid flow with variable viscosity and for random changes of human hip joint gap. According to the author's knowledge the problem of human joint lubrication in unsteady motion has not been hitherto considered in the scientific papers on biotribology.
PL
Praca przedstawia pewien model obliczeń wartości sił tarcia zapisany w ortogonalnych sferycznych i innych krzywoliniowych układach współrzędnych dla hydrodynamicznego, niesymetrycznego przepływu cieczy synowialnej o własnościach nienewtonowskich i zmiennej lepkości w szczelinie stawu biodrowego człowieka z uwzględnieniem zmian losowych. Według informacji autora tak przedstawiony model nie był do tej pory rozpatrywany w pracach naukowych w problemach niestacjonarnego smarowania stawów człowieka. W pracy zostały zastosowane warunki brzegowe Beaversa dla przepływu cieczy synowialnej w szczelinie stawu biodrowego człowieka przy uwzględnieniu miękkiej porowatej chrząstki stawowej. Warunki Beaversa w nowym zastosowaniu pozwalają uwzględnić dodatkową wartość prędkości stycznej na powierzchni chrząstki w trakcie smarowania. Ta wartość prędkości ma istotny wpływ na powstające siły tarcia w trakcie smarowania.
EN
The propagation of plane waves in a rotating homogeneous, isotropic, thermoelastic solid with double porosity following Lord-Shulman’s theory of thermoelasticity has been investigated. It is assumed that the medium rotates about an axis normal to the surface with a uniform angular velocity. There may exist five coupled waves that evolved due to the longitudinal, transverse disturbance, voids of type-I and type-II, and temperature change in the medium. The secular equation for the model under consideration has been derived with the help of formal solutions and boundary conditions. The amplitude of displacements, temperature change and volume fraction fields for voids of type-I and type-II have also been computed analytically. Finally, numerical computations have been carried out for magnesium crystal material to understand the behavior of amplitude of phase velocity, penetration depth, specific loss, displacement components, temperature change, and volume fraction field due to type-I and type-II voids corresponding to the different rotation rates. Various graphs have been plotted to support the analytical findings. The study may be used in the development of rotation sensors, material design and thermal efficiency.
EN
The effect of throughflow on a layer of a rotating fluid heated from below in porous medium in the presence of vertical magnetic field is considered. For the case of stationary convection, the rotation has always a stabilizing effect. The medium permeability has always a destabilizing effect whereas the magnetic field and the throughflow have always a stabilizing effects in the absence of rotation. But in the presence of rotation, the medium permeability is found to have a destabilizing effect whereas the magnetic field and the throughflow have a stabilizing effects under certain conditions. Graphs have been plotted by giving numerical values to the parameters, to depict the stability characteristics. The magnetic field and rotation introduce oscillatory modes in the system, which were nonexistent in their absence. The sufficient conditions for non-existence of the overstability are also obtained.
EN
In the present problem we study the deformation of a rotating generalized thermoelastic medium with hydrostatic initial stress subjected to three different type of sources. The components of displacement, force stress and temperature distribution are obtained in Laplace and Fourier domain by applying integral transforms. The general solution obtained is applied to a specific problem of a half-space subjected to concentrated force, distributed force and a moving source. These components are then obtained in the physical domain by applying a numerical inversion method. Some particular cases are also discussed in context of the problem. The results are also presented graphically to show the effect of rotation and hydrostatic initial stress.
EN
The aim of the research was to explore the ability of spatial imagery in blind students, particularly their abilities to scan and mentally rotate tactile objects’ shapes. The results demonstrate that the older the blind children are, the easier it is for them to differentiate shapes, but only in case when one of two objects is rotated. It may mean that the ability of mental rotation is developing during the school years, and the spatial scanning ability is achieved at an earlier age. It was also stated that identification of objects’ shapes is more accurate in an aligned condition than in a rotated condition. It suggests that the mental rotation process is more complicated than the scanning process for blind children to perform.
PL
W badaniach zaprezentowanych w artykule podjęto zagadnienie zdolności wyobrażeniowych niewidomych dzieci w zakresie skaningu i rotacji kształtu obiektów percypowanych dotykowo. Stwierdzono, że im starsze jest dziecko, tym lepiej różnicuje ono kształty dotykanych obiektów, ale jedynie w sytuacji, gdy kształty te względem siebie obrócono. Uzyskane wyniki wskazują na to, iż u niewidomych dzieci w okresie szkolnym doskonali się zdolność rotacji, zaś umiejętność skaningu jest osiągnięciem wcześniejszym rozwojowo. Zaobserwowano również, że trafność identyfikacji kształtu obiektów jest większa w sytuacji, gdy są one ustawione względem siebie w tej samej pozycji, niż gdy znajdują się w różnych pozycjach. Rotacja umysłowa stanowi więc dla niewidomych dzieci trudniejszą do wykonania operację wyobrażeniową niż skaning przestrzeni.
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