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Horizontal Plane (horizontal + plane)
Selected AbstractsSolar UV Geometric Conversion Factors: Horizontal Plane to Cylinder Model,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2010Stanley J. Pope Most solar UV measurements are relative to the horizontal plane. However, problems arise when one uses those UV measurements to perform risk or benefit assessments because they do not yield the actual doses people get while they are outdoors. To better estimate the UV doses people actually get while outdoors, scientists need geometric conversion factors (GCF) that change horizontal plane irradiances to average irradiances on the human body. Here we describe a simple geometric method that changes unweighted, erythemally weighted and previtamin D3 -weighted UV irradiances on the horizontal plane to full cylinder and semicylinder irradiances. Scientists can use the full cylinder model to represent the complete human body, while they can use the semicylinder model to represent the face, shoulders, tops of hands and feet. We present daily, monthly and seasonally calculated averages of the GCF for these cylinder models every 5° from 20 to 70°N so that scientists can now get realistic UV doses for people who are outdoors doing a variety of different activities. The GCF show that people actually get less than half their annual erythemally weighted, and consequently half their previtamin D3 -weighted, UV doses relative to the horizontal plane. Thus, scientists can now perform realistic UV risk and benefit assessments. [source] Effectiveness of limited cone-beam computed tomography in the detection of horizontal root fractureDENTAL TRAUMATOLOGY, Issue 3 2009vanç Kamburo Root fractures were created in the horizontal plane in 18 teeth by a mechanical force and fragments were relocated. Another 18 intact teeth with no horizontal root fracture served as a control group. Thirty-six teeth were placed in the respective empty maxillary anterior sockets of a human dry skull in groups three by three. Intraoral radiographs were obtained in three different vertical views by utilizing Eastman Kodak E-speed film, CCD sensor, RVG 5.0 Trophy and a PSP sensor Digora, Optime. Cone beam CT images were taken with a unit (3D Accuitomo; J Morita MFG. Corp, Kyoto, Japan). Three dental radiologists separately examined the intraoral film, PSP, CCD and cone beam CT images for the presence of horizontal root fracture. Specificity and sensitivity for each radiographic technique were calculated. Kappa statistics was used for assessing the agreement between observers. Chi-square statistics was used to determine whether there were differences between the systems. Results were considered significant at P < 0.05. Cone beam CT images revealed significantly higher sensitivities (P < 0.05) than the intraoral systems between which no significant differences were found. Specificities did not show any statistically significant differences between any of the four systems. The kappa values for inter-observer agreement between observers (four pairs) ranged between 0.82,0.90 for the 3DX evaluations and between 0.63,0.71 for the different types of intraoral images. Limited cone beam CT, outperformed the two-dimensional intraoral, conventional as well as digital, radiographic methods in detecting simulated horizontal root fracture. [source] Response of a double-wedge base-isolation deviceEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 13 2004J. Enrique Luco Abstract A novel base-isolation device is described and its performance is compared with that of a friction pendulum bearing. In its simplest form, the device consists of two wedges sliding on a horizontal plane in opposite directions and constrained from retreating by ratchets or bilinear dampers. The superstructure rests at the intersection of the two wedges. For a sufficiently large horizontal acceleration of the base, the structure starts to move up the inclined plane of one of the wedges, which remains fixed while the second wedge is slaved to follow the structure. As the direction of the base acceleration reverses, the process is reversed and the structure starts to climb on the second inclined plane while the first wedge follows. The overall result is that the horizontal acceleration of the structure is reduced with respect to that of the base and that kinetic energy associated with horizontal velocities is systematically transformed into potential energy. In the case of motion in a vertical plane, the device has the following advantages over a friction pendulum: (i) the sliding surface is linear instead of curved, (ii) kinetic energy is systematically transformed into potential energy during the strong ground motion, and (iii) the device is slowly self-centering. Copyright © 2004 John Wiley & Sons, Ltd. [source] Evidence from proprioception of fusimotor coactivation during voluntary contractions in humansEXPERIMENTAL PHYSIOLOGY, Issue 3 2008Trevor J. Allen In experiments on position sense at the elbow joint in the horizontal plane, blindfolded subjects were required to match the position of one forearm (reference) by placement of their other arm (indicator). Position errors were measured after conditioning elbow muscles of the reference arm with an isometric contraction while the arm was held either flexed or extended. The difference in errors after the two forms of conditioning was large when the conditioned muscles remained relaxed during the matching process and it became less when elbow muscles were required to lift a load during the match (10 and 25% of maximal voluntary contraction, respectively). Errors from muscle conditioning were attributed to signals arising in muscle spindles and were hypothesized to result from the thixotropic property of passive intrafusal fibres. Active muscle does not exhibit thixotropy. It is proposed that during a voluntary contraction the errors after conditioning are less, because the spindles become coactivated through the fusimotor system. The distribution of errors is therefore seen to be a reflection of fusimotor recruitment thresholds. For elbow flexors most, but not all, fusimotor fibres appear to be recruited by 10% of a maximal contraction. [source] Bumble bee preference for flowers arranged on a horizontal plane versus inclined planesFUNCTIONAL ECOLOGY, Issue 6 2008T. T. Makino Summary 1Determining factors affecting pollinator visitation is the key to understanding the reproductive success of animal-pollinated plants. The inclination of the ground where plants grow, which has been little studied, could be one such factor. There may be differences in foraging performance when visiting flowers on horizontal planes compared with flowers on inclines planes. And if this is the case, pollinators may have a preference for horizontal or inclined planes. To test these possibilities, a series of laboratory experiments with bumble bees and arrays of artificial flowers were conducted. 2In the first experiment, bees were presented with a pair of floral arrays, one on a horizontal plane and one sloping. The bees preferred visiting flowers on the horizontal array. 3In the second experiment, bees were allowed to forage on a flower array tilted at various angles ranging from 0° (horizontal) to 90° (vertical). It was found that their foraging performance decreased with increasing angles, showing a 9·1% reduction from 0° to 90° arrays. This reduction was caused by an increased travel time between flowers, when moving upslope or downslope. 4These results suggest that plants growing on steep slopes may be less preferred by pollinators. Future studies are needed to clarify how slopes affect pollinator behaviour in field conditions and the ecological influences on plant reproduction. [source] Scattering behaviour at Merapi volcano (Java) revealed from an active seismic experimentGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2001Ulrich Wegler SUMMARY The seismic structure of the stratovolcano Merapi (Java, Indonesia) was studied using an active seismic experiment. Three 3 km long seismic profiles each consisting of up to 30 three-component seismometers with an interstation distance of 100 m were built up in an altitude range between 1000 and 2000 m above sea level. The detailed study of the seismic properties of the propagation media in active volcanic regions is important to understand the natural seismic signals used for eruption forecasting. The seismic experiment at Merapi therefore concentrates on the heterogeneous structure within a radius of 5 km from the active dome, where the sources of most of the natural volcanic seismic events are located. The cone of Merapi volcano consists of different materials changing on a small scale due to the layering of eruptive material. Additionally, the topography of the erosion valleys leads to an irregular deposition, which cannot be described by a simple 1-D layering. These inhomogeneities have a strong influence on seismic signals. The direct P and S waves are attenuated quickly and show only small amplitudes on seismograms. The energy lost from the direct waves, however, is not changed into heat but scattered and can be observed as seismic coda following the direct waves. The observed seismograms show a spindle-like amplitude increase after the direct P phase. This shape of the envelope can be explained by the diffusion model. According to this model there are so many strong inhomogeneities that the direct wave can be neglected and all energy is concentrated in multiple scattered waves. Besides the envelope, the coherence and polarization properties of the wavefield also indicate strong scattering. Only the first onset shows coherence over a station spacing of 100 m, whereas the late phases carrying the major part of the energy are mainly incoherent. The horizontal components of the seismograms have larger amplitudes than the vertical component, but within the horizontal plane the polarization is almost arbitrary, corresponding to waves arriving from scatterers located arbitrarily in space. As a result of the inversion using the diffusion model we obtain values of the S -wave scattering attenuation coefficient, ,s, and the S -wave intrinsic absorption coefficient, ,i. In the frequency range of 4,20 Hz used in this study the scattering attenuation is at least one order of magnitude larger than the intrinsic absorption (,s,,i). The mean free path of S waves is as low as 100 m (,s,1,100 m). The scattering coefficient is independent of frequency (,s,f0.0), whereas the coefficient of intrinsic attenuation increases with increasing frequency (,i,f1.6). The natural seismic signals at Merapi volcano show similar characteristics to the artificial shots. The first onsets have only small amplitudes and the energy maximum arrives delayed compared to the direct waves. Therefore, these signals appear to be strongly affected by multiple scattering also. [source] Enhancement of natural convection heat transfer from a vertical heated plate using inclined finsHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2007Masao Fujii Abstract An enhancement technique is developed for natural convection heat transfer from a vertical heated plate with inclined fins, attached on the vertical heated plate to isolate a hot air flow from a cold air flow. Experiments are performed in air for inclination angles of the inclined fins in the range of 30° to 90° as measured from a horizontal plane, with a height of 25 to 50 mm, and a fin pitch of 20 to 60 mm. The convective heat transfer rate for the vertical heated plate with inclined fins at an inclination angle of 60° is found to be 19% higher than that for a vertical heated plate with vertical fins. A dimensionless equation on the natural convection heat transfer of a vertical heated plate with inclined fins is presented. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(6): 334,344, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20168 [source] Localization of root canal orifices in mandibular second molars in relation to occlusal dimensionINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2009O. Gorduysus Abstract Aim, To evaluate the localization and distribution of canal orifices of mandibular second molar teeth in relation to the mesio-distal and bucco-lingual dimensions of coronal tissue. Methodology, Fifty extracted mandibular second molar teeth were embedded into plaster blocks with their vertical axes aligned perpendicular to the horizontal plane. The teeth were photographed digitally from the occlusal aspect under 12 × magnification. Thereafter, the occlusal halves of crowns were sectioned off to expose the root canal orifices. The teeth were than photographed under the same magnification, after which the pre- and post-sectioning images of each specimen were stacked into a single file. To plot the coordinate of each canal orifice, a 0.5-mm grid analytical plane was mounted digitally on the stack so that the x - and y -axes of the plane were superimposed on the mesiodistal and buccolingual axes (bisectors) of the tooth crowns. Localization and distribution of the coordinates of the canal orifices were evaluated using the chi-square test (P = 0.05). Results, Only one tooth displayed a single root canal orifice, located in the mesiobuccal-distolingual ,centre' of the occlusal surface. The majority of mandibular second molars had three orifices (72%), followed by those with two (16%) and four (10%). The distal canal was located lingual to the centre of the occlusal plane. Conclusion, The distal canal was located lingual to the centre of the occlusal plane of mandibular second molars. The possibility of observing more divergent localizations and orifice numbers should not be overlooked in clinical practice. [source] Non-hydrostatic 3D free surface layer-structured finite volume model for short wave propagationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2009L. Cea Abstract In this paper a layer-structured finite volume model for non-hydrostatic 3D environmental free surface flow is presented and applied to several test cases, which involve the computation of gravity waves. The 3D unsteady momentum and mass conservation equations are solved in a collocated grid made of polyhedrons, which are built from a 2D horizontal unstructured mesh, by just adding several horizontal layers. The mesh built in such a way is unstructured in the horizontal plane, but structured in the vertical direction. This procedure simplifies the mesh generation and at the same time it produces a well-oriented mesh for stratified flows, which are common in environmental problems. The model reduces to a 2D depth-averaged shallow water model when one single layer is defined in the mesh. Pressure,velocity coupling is achieved by the Semi-Implicit Method for Pressure-Linked Equations algorithm, using Rhie,Chow interpolation to stabilize the pressure field. An attractive property of the model proposed is the ability to compute the propagation of short waves with a rather coarse vertical discretization. Several test cases are solved in order to show the capabilities and numerical stability of the model, including a rectangular free oscillating basin, a radially symmetric wave, short wave propagation over a 1D bar, solitary wave runup on a vertical wall, and short wave refraction over a 2D shoal. In all the cases the numerical results are compared either with analytical or with experimental data. Copyright © 2008 John Wiley & Sons, Ltd. [source] Thermal conductivity of wool and wool,hemp insulationINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2006Z. Ye Abstract Measurements have been obtained for the thermal resistance of sheep-wool insulation and wool,hemp mixtures, both in the form of bonded insulation batts, using a calibrated guarded hot-box. The density was 9.6,25.9 kg m,3 for the wool and 9.9,18.1 kg m,3 for the wool,hemp mixtures. The measurements were made at a mean sample temperature of 13.3°C using a calibrated guarded hot-box. The estimated uncertainly in the resistance measurements was of the order of ±7%. The thermal conductivity of the samples, derived from the thermal resistance measurements on the basis of the measured thickness, was well correlated with the density, although the variation with density was larger than that obtained in previous studies. The conductivity of the wool,hemp samples was not significantly different from that of the wool samples at the same density. Moisture uptake produced an increase of less than 5% in the conductivity of the bonded wool insulation for an increase in absorbed moisture content of 20%. The thermal resistance was 1.6% lower on average for samples oriented in the horizontal plane rather than the vertical plane, but this difference is not significant. Copyright © 2005 John Wiley & Sons, Ltd. [source] An application of dynamic positioning control using wave feed forwardINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 13 2001A. B. Aalbers Abstract The paper presents the results of model tests for a large tanker in which wave drift force feed forward was applied in the dynamic positioning control system. The estimation method of the nonlinear (second order) wave drift forces from the measurement of relative water motions at the side of a ship hull is presented. The estimated wave drift forces are used in the DP control system, to enhance the filter process of the extended Kalman filter, and in the required thruster set-points. The EKF uses the nonlinear equations of low-frequency ship motions on the horizontal plane, which are also presented. The results of the model tests show that the use of wave drift force feed forward significantly improves the positioning accuracy in sea states with 3.5 m significant wave height or higher. Copyright © 2001 John Wiley & Sons, Ltd. [source] Leaflet Movement of Robinia pseudoacacia in Response to a Changing Light EnvironmentJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 4 2007Cheng-Cheng Liu Abstract Diurnal and nocturnal leaflet movement of black locust (Robinia pseudoacacia L.) was investigated under three light schemes: 100% natural irradiance, 50% shading, and 90% shading. Changes in leaf mid-vein angle were described by measurements of two planes: (i) ,, the angle formed by the bottom of the petiolule and its relation to the horizontal plane; and (ii) ,, the angle between the petiolule and the main leaflet vein. The two highest light regimens had a significant effect on ,. Variation in , tends to make the leaflet more erect, thereby minimizing any negative impact of high irradiance on leaf lamina. Light-dark rhythms induced variation in , (termed nyctinastic movement). Nyctinastic movement is important during the low light levels experienced by leaflets in early morning and late afternoon. At low light levels, the leaflet stopped nyctinastic movement and , was fixed at an angle that may have enabled the leaf lamina to maximize light interception. After the light-dark cycle was reestablished, nyctinastic movement was restored. Taken together, our results suggest that irradiance induces variation in , leading to diurnal leaflet movement (diaheliotropism), whereas the light-dark cycle influences ,, which results in nocturnal leaflet movement. Both angles are important for describing patterns of leaf movement in R. pseudocacia. [source] Role of various elliptical shapes for efficient microwave processing of materialsAICHE JOURNAL, Issue 6 2007Tanmay Basak Abstract A detailed theoretical analysis has been carried out to assess the role of various elliptical shapes/cross sections on microwave heating of 2-D cylinders for beef and oil samples. Two types of elliptical cross sections are considered as type A (ellipse with major axis along the horizontal plane), and type B (ellipse with minor axis along the horizontal plane.) A preliminary analysis on microwave heating of samples has been shown via average power within a sample vs. sample radius of circular cross section for beef and oil samples. Several regimes (I,III) based on small and large radius for circular cross sections have been selected. The effect of elliptical shapes for type A and B configurations has been studied initially via average power vs. aspect ratio distributions for various regimes. The grayscale images of power absorption have been analyzed further for elliptical cross section with varying aspect ratios for regimes I,III where aspect ratio and types of configuration are shown to influence spatial power absorptions. The detailed temperature profiles have also been shown to illustrate the role of elliptical shapes on uniform heating and thermal runaway. Depending on the material dielectric properties and sample dimension, either type A or B or both configuration has been recommended. © 2007 American Institute of Chemical Engineers AIChE J, 2007 [source] Locomotor skills and balance strategies in children with internal rotations of the lower limbsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2008Sophie Mallau Abstract The purpose of this study was to investigate the functional effects of a structural deformation, internal rotations (IR) of the lower limbs, on upper body balance strategies used during locomotion in 5,6 year-old and 7,10 year-old children. Balance control was examined in terms of rotation around the longitudinal axis in horizontal plane (yaw) and around the sagittal axis in a frontal plane (roll). Kinematics of foot, pelvis, shoulder, and head rotations were measured with an automatic optical TV image processor and used to calculate angular dispersions and segmental stabilizations. Older children with IR showed a lower gait velocity, particularly in difficult balance conditions than typically developing (TD) children. In younger children, the effect of the local biomechanical deficit remained limited to the lower limbs and did not affect upper body coordination. By contrast, in older children with IR, the development of head stabilization in space was affected. This was demonstrated by an "en bloc" instead of an articulated mode of head-trunk unit systematically adopted by the control group. As pelvic stabilization remains the main reference frame to organize balance control in older children with IR, we conclude that the structural deformity of the legs affect and possibly delay the acquisition of the head stabilization in space strategy. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:117,125, 2008 [source] Modelling the spread in space and time of an airborne plant diseaseJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 3 2008Samuel Soubeyrand Summary., A spatiotemporal model is developed to analyse epidemics of airborne plant diseases which are spread by spores. The observations consist of measurements of the severity of disease at different times, different locations in the horizontal plane and different heights in the vegetal cover. The model describes the joint distribution of the occurrence and the severity of the disease. The three-dimensional dispersal of spores is modelled by combining a horizontal and a vertical dispersal function. Maximum likelihood combined with a parametric bootstrap is suggested to estimate the model parameters and the uncertainty that is attached to them. The spatiotemporal model is used to analyse a yellow rust epidemic in a wheatfield. In the analysis we pay particular attention to the selection and the estimation of the dispersal functions. [source] Solar UV Geometric Conversion Factors: Horizontal Plane to Cylinder Model,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2010Stanley J. Pope Most solar UV measurements are relative to the horizontal plane. However, problems arise when one uses those UV measurements to perform risk or benefit assessments because they do not yield the actual doses people get while they are outdoors. To better estimate the UV doses people actually get while outdoors, scientists need geometric conversion factors (GCF) that change horizontal plane irradiances to average irradiances on the human body. Here we describe a simple geometric method that changes unweighted, erythemally weighted and previtamin D3 -weighted UV irradiances on the horizontal plane to full cylinder and semicylinder irradiances. Scientists can use the full cylinder model to represent the complete human body, while they can use the semicylinder model to represent the face, shoulders, tops of hands and feet. We present daily, monthly and seasonally calculated averages of the GCF for these cylinder models every 5° from 20 to 70°N so that scientists can now get realistic UV doses for people who are outdoors doing a variety of different activities. The GCF show that people actually get less than half their annual erythemally weighted, and consequently half their previtamin D3 -weighted, UV doses relative to the horizontal plane. Thus, scientists can now perform realistic UV risk and benefit assessments. [source] Study of UV Radiation Dose Received by the Spanish PopulationPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2007Gonzalo Gurrea Excess exposure to UV radiation can affect our health by causing sunburn, skin cancer, etc. It is therefore useful to determine the UV dosage received by people as a way of protecting them from the possible negative effects that this kind of radiation can cause. In this work, the personal outdoor percentage, which shows the time spent in outdoor activities, as well as personal UV doses, has been calculated by means of global UV radiation on a horizontal plane. A database of average daily UVB radiation on the horizontal plane given by the National Institute of Meteorology has been used. In this work we evaluate the standard erythema dose of the Spanish population throughout the year. [source] UV Exposure of Elementary School Children in Five Japanese Cities,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Masaji Ono ABSTRACT A 1 week UV-exposure measurement and outdoor-activity pattern survey was conducted for elementary school children for four seasons at five sites in Japan, i.e. Sapporo (43°05,N, altitude 40 m), Tsukuba (36°05,N, 20 m), Tokyo (35°40,N, 45 m), Miyazaki (31°60,N, 40 m) and Naha (26°10,N, 5 m), and UV exposure was measured directly and estimated using outdoor-activity records. The study site with largest UV exposure was Miyazaki, a southern rural area. Comparing the results for boys and girls, UV exposure was larger in boys. UV exposure was large in spring and summer and small in winter. The total amount of UV exposure in spring and summer contributed 57.7,73.4% of total exposure for the year. As a whole, 8.1% and 1.8% of the schoolchildren were exposed to more than 1 minimum erythemal dose (MED) and 2 MED of solar UV in a day, respectively. The estimated yearly UV exposure ranged from 49 207 J/m2 in Miyazaki to 31 520 J/m2 in Tsukuba. The actual UV exposure correlated to potential UV exposure, estimated using outdoor-activity records and ambient UV irradiance, but the ratio differed by season and site. The yearly average of percent UV exposure to ambient UV on a horizontal plane ranged from 9.9% in Tokyo to 4.0% in Naha. In the questionnaire survey on outdoor-activity pattern, a short question "How long did you spend time outdoors between 0900 and 1500 h?" gives the best estimates of UV exposure. [source] UV Index Experimental Values During the Years 2000 and 2001 from the Spanish Broadband UV-B Radiometric Network,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2002José A. Martínez-Lozano ABSTRACT An analysis is made of experimental ultraviolet erythemal solar radiation data measured during the years 2000 and 2001 by the Spanish UV-B radiation evaluation and prediction network. This network consists of 16 Robertson,Berger type pyranometers for evaluating solar erythemal radiation and five Brewer spectroradiometers for evaluating the stratospheric ozone. On the basis of these data the Ultraviolet Index (UVI) was evaluated for the measuring stations that are located either in coastal regions or in the more densely populated regions inland on the Iberian Peninsula. It has been checked that in most cases the maximum irradiance values corresponded to solar noon, although there were exceptions that could be explained by cloudiness. The maximum experimental values of the UVI were around 9 during the summer, though frequently passing this value at the inland measurement stations. The annual accumulated dose of irradiation on a horizontal plane has also been studied, as well as the evolution through the year in units of energy, standard erythemal doses and minimum erythemal doses, according to different phototypes. [source] Novel reconstruction of the orientation of the pectoral girdle in sauropodsTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 1 2007Daniela Schwarz Abstract The orientation of the scapulocoracoid in sauropod dinosaurs is reconstructed based on comparative anatomical investigations of pectoral girdles of extant amniotes. In the reconstruction proposed here, the scapula of sauropods stands at an angle of at least 55° to the horizontal plane in mechanical coherence with the sternal apparatus including the coracoids. The coracoids are oriented cranioventrally to the rib cage and the glenoid is directed mediolaterally, which allows the humerus to swing in a sagittal plane. The inclination of the scapula to the horizontal plane is reconstructed for Diplodocus (60,65°), Camarasaurus (60,65°), and Opisthocoelicaudia (55,65°). The inclination of the scapulocoracoid has consequences for the overall body posture in Camarasaurus and Opisthocoelicaudia, where the dorsal contour would have ventrally declined toward the sacrum. Scapulocoracoid mobility depends on the arrangement of clavicles, the reconstruction of a coracosternal joint, and the reconstructed musculature of the shoulder girdle. In a crocodylian model of the shoulder musculature, m. serratus profundus and superficialis form a muscular sling, which suspends the trunk from the shoulder girdle and would allow a certain mobility of the scapulocoracoid. An avian model of the shoulder musculature would also mean suspension by means of the m. serratus complex, but indicates a closer connection of the scapula to the dorsal ribs, which would lead to more restricted movements of the scapulocoracoid in sauropods. Anat Rec, 290:32,47, 2007. © 2006 Wiley-Liss, Inc. [source] Free Convective Mass Transfer Behaviour of Inclined Cylinders with Active EndsTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2003Inderjit Nirdosh Abstract Rates of mass transfer at inclined cylinders with active ends were determined under natural convection conditions by measuring the limiting current of copper deposition from acidified copper sulphate. Physical properties of the solution, cylinder dimensions and inclination were varied to produce a ScGr range of 1.53 × 109 to 7 × 1010. Under these conditions the data for different orientations were correlated by Sh = 1.075 (ScGr)0.242. The characteristic length used in obtaining Sh and Gr was calculated by dividing the cylinder surface area by the cylinder perimeter projected onto the horizontal plane. At high CuSO4 concentrations a reasonable agreement was found between the experimental rate of mass transfer and that calculated by summing the rate of mass transfer at individual surfaces of the cylinder. Deviations were observed at low CuSO4 concentrations, and the possible causes of the deviations were explained. On a déterminé les taux de transfert de matière dans le cas de cylindres inclinés aux extrémités actives dans des conditions de convection naturelle, en mesurant le courant limite du dépôt de cuivre venant de sulfate de cuivre acidifié. On a fait varier les propriétés physiques de la solution, les dimensions de cylindre et l'inclinaison pour donner une gamme de ScGr de 1.53 × 109 to 7 × 1010. Dans ces conditions, les données pour différentes orientations ont été corrélées par Sh = 1.075 (ScGr)0.242. La longueur caractéristique utilisée pour obtenir Sh et Gr a été calculée en divisant la superficie du cylindre par le périmètre projeté sur un plan horizontal. À de fortes concentrations de CuSO4, un accord raisonnable est trouvé entre le taux de transfert de matière expérimental et celui qui est obtenu en faisant la somme des taux de transfert de matière sur les différentes surfaces du cylindre. Des écarts sont observés à de faibles concentrations de CuSO4, et les causes possibles de ces écarts sont expliquées. [source] Boundary-layer variations due to orographic-wave breaking in the presence of rotationTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 603 2004B. Grisogono Abstract A mesoscale numerical model is used to study the atmospheric boundary-layer (ABL) response to nonlinear orographic forcing with Coriolis effect, f, over a mountain with length (the cross-wind component) comparable to the Rossby radius of deformation, LR. The orographic-wave breaking occurring for Froude number Fr<1, affected by f>0, intensifies on the northern flank for westerly flows, as also found in other recent studies. A cumulative effect occurs as the Coriolis force lifts the northern ABL top and generates a stronger low-level jet (LLJ) than on the southern side. A differential layering also appears, since the specific humidity is higher in the lower southern ABL than in the related northern ABL, and vice versa. By contrast, there are higher values of the turbulent kinetic energy and humidity in the upper northern ABL. The breaking of flow symmetry around the orography due to f changes both the vertical vorticity and horizontal divergence field, (,, D), it modulates eddies and turbulence leading to the differential layering of the ABL. The stronger northern LLJ and its weaker southern counterpart, both meandering, together with the asymmetric wave breaking, induce strong lee-side fluctuations of the (,, D) field in the presence of f. The enhanced (,, D) production due to wave breaking over the distance , LR, the primary atmosphere,orography resonance occurs mainly in the vertical, while the ,f -enhancement' occurs in the horizontal plane. In this way, the initial mesoscale forcing may extend its effects over the synoptic scale. Copyright © 2004 Royal Meteorological Society [source] Stabilization of the inverted spherical pendulum via Lyapunov approach,ASIAN JOURNAL OF CONTROL, Issue 6 2009O. Octavio Gutiérrez F. Abstract In this paper a nonlinear controller is presented for the stabilization of the spherical inverted pendulum system. The control strategy is based on the Lyapunov approach in conjunction with LaSalle's invariance principle. The proposed controller is able to bring the pendulum to the unstable upright equilibrium point with the position of the movable base at the origin. The obtained closed-loop system has a very large domain of attraction, that can be as large as desired, for any initial position of the pendulum which lies above the horizontal plane. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] On the dynamics of a spherical scaffold in rotating bioreactorsBIOTECHNOLOGY & BIOENGINEERING, Issue 3 2003L. E. S. Ramirez Abstract We analyze the dynamics of a spherical scaffold in rotating bioreactors (or clinostats). The idealized clinostat environment consists of a purely rotational flow that is perpendicular to a gravitational field. We confirm through a detailed analytical study that lift effects considerably alter the position of the equilibrium point reached by the scaffolds in the (vertical) direction collinear to the gravitational field. This result holds for small particle and shear Reynolds numbers. Our analysis shows that the inertial lift effect is negligible in the horizontal direction. We show that for all rotations of practical interest, and for the range of particle Reynolds number smaller than unity, the vertical coordinate of the equilibrium point is strongly affected by consideration of lift effects. For light (heavy) particles, inclusion of lift in the formation forces the equilibrium position to be below (above) the horizontal plane that contains the axis of rotation. The equilibrium point for light particles is stable and therefore is observable experimentally. The equilibrium point for heavy particles is unstable. We also estimate the stress level applied to the scaffold and derive an algebraic expression that indicates that the stress level acting on the scaffold decreases with increasing shear Reynolds number. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 382,389, 2003. [source] Bumble bee preference for flowers arranged on a horizontal plane versus inclined planesFUNCTIONAL ECOLOGY, Issue 6 2008T. T. Makino Summary 1Determining factors affecting pollinator visitation is the key to understanding the reproductive success of animal-pollinated plants. The inclination of the ground where plants grow, which has been little studied, could be one such factor. There may be differences in foraging performance when visiting flowers on horizontal planes compared with flowers on inclines planes. And if this is the case, pollinators may have a preference for horizontal or inclined planes. To test these possibilities, a series of laboratory experiments with bumble bees and arrays of artificial flowers were conducted. 2In the first experiment, bees were presented with a pair of floral arrays, one on a horizontal plane and one sloping. The bees preferred visiting flowers on the horizontal array. 3In the second experiment, bees were allowed to forage on a flower array tilted at various angles ranging from 0° (horizontal) to 90° (vertical). It was found that their foraging performance decreased with increasing angles, showing a 9·1% reduction from 0° to 90° arrays. This reduction was caused by an increased travel time between flowers, when moving upslope or downslope. 4These results suggest that plants growing on steep slopes may be less preferred by pollinators. Future studies are needed to clarify how slopes affect pollinator behaviour in field conditions and the ecological influences on plant reproduction. [source] Mechanics of land subsidence due to groundwater pumpingINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 14 2010Muniram Budhu Abstract This paper presents the formulation of the basic mechanics governing the changes in stress states from groundwater pumping and comparisons among predicted land subsidence from this mechanics with existing analyses and field data. Land subsidence is a growing, global problem caused by petroleum and groundwater withdrawal, mining operations, natural settlement, hydro-compaction, settlement of collapsible soils, settlement of organic soils and sinkholes. This paper is concerned with the land subsidence due to groundwater level decline by groundwater pumping. It is shown that the stress state consists of asymmetric stresses that are best simulated by a Cosserat rather than a Cauchy continuum. Land subsidence from groundwater level decline consists of vertical compression (consolidation), shear displacement and macro-rotation. The latter occurs when conditions are favorable (e.g. at a vertical interface) for the micro-rotation imposed by asymmetric stresses to become macro-rotation. When the length of the cone of depression is beyond ,2 times the thickness of the aquifer, simple shear on vertical planes with rotation is the predominant deformation mode. Otherwise, simple shear on horizontal planes is present. The predicted subsidence using the mechanics developed in this paper compares well with data from satellite-borne interferometric synthetic aperture radar. Copyright © 2009 John Wiley & Sons, Ltd. [source] High-resolution study of dynamical diffraction phenomena accompanying the Renninger (222/113) case of three-beam diffraction in siliconACTA CRYSTALLOGRAPHICA SECTION A, Issue 4 2010A. Kazimirov X-ray optical schemes capable of producing a highly monochromatic beam with high angular collimation in both the vertical and horizontal planes have been evaluated and utilized to study high-resolution diffraction phenomena in the Renninger (222/113) case of three-beam diffraction in silicon. The effect of the total reflection of the incident beam into the nearly forbidden reflected beam was observed for the first time with the maximum 222 reflectivity at the 70% level. We have demonstrated that the width of the 222 reflection can be varied many times by tuning the azimuthal angle by only a few µrad in the vicinity of the three-beam diffraction region. This effect, predicted theoretically more than 20 years ago, is explained by the enhancement of the 222 scattering amplitude due to the virtual two-stage 000 113 222 process which depends on the azimuthal angle. [source] | ||||||||||||||||||||||