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Longitudinal Direction (longitudinal + direction)
Selected AbstractsThe eigenvalues of isolated bridges with transverse restraints at the end abutmentsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2010Nicos Makris Abstract This paper examines the eigenvalues of multi-span seismically isolated bridges in which the transverse displacement of the deck at the end abutments is restricted. With this constraint the deck is fully isolated along the longitudinal direction, whereas along the transverse direction the deck is a simple-supported beam at the end abutments which enjoys concentrated restoring forces from the isolation bearings at the center piers. For moderate long bridges, the first natural period of the bridge is the first longitudinal period, while the first transverse period is the second period, given that the flexural rigidity of the deck along the transverse direction shortens the isolation period offered by the bearings in that direction. This paper shows that for isolated bridges longer than a certain critical length, the first transverse period becomes longer than the first longitudinal period despite the presence of the flexural rigidity of the deck. This critical length depends on whether the bridge is isolated on elastomeric bearings or on spherical sliding bearings. This result is also predicted with established commercially available numerical codes only when several additional nodes are added along the beam elements which are modeling the deck in-between the bridge piers. On the other hand, this result cannot be captured with the limiting idealization of a beam on continuous distributed springs (beam on Wrinkler foundation),a finding that has practical significance in design and system identification studies. Finally, the paper shows that the normalized transverse eigenperiods of any finite-span deck are self-similar solutions that can be represented by a single master curve and are independent of the longitudinal isolation period or on whether the deck is supported on elastomeric or spherical sliding bearings. Copyright © 2009 John Wiley & Sons, Ltd. [source] Seismic performance evaluation of steel arch bridges against major earthquakes.EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 14 2004Part 2: simplified verification procedure Abstract The performance-based philosophy has been accepted as a more reasonable design concept for engineering structures. For this purpose, capacity evaluation and demand prediction procedures for civil engineering structures under earthquake excitations are of great significance. This work presents a displacement-based seismic performance verification procedure including capacity and seismic demand predictions for steel arch bridges and investigates its applicability. Pushover analyses is employed as a basis in this method to investigate the structure's behaviors. A failure criterion for steel members accounting for the effect of local buckling is involved and an equivalent single-degree-of-freedom (ESDOF) system with a simplified bilinear hysteretic model formulated using pushover analyses results is introduced to estimate the displacement capacity and maximum demand of steel arch bridges under major earthquakes. To check the accuracy of the proposed method, seismic capacities and demands from multi-degree-of-freedom (MDOF) time-history analyses with Level-II design earthquake record inputs modeling major earthquakes are used as benchmarks for comparison. By a case study, it is clarified that the proposed prediction procedure can give accurate estimations of displacement capacities and demands of the steel arch bridge in the transverse direction, while insufficient for the longitudinal direction, which confirms the conclusion drawn in other structure types about the applicability of pushover analyses. Copyright © 2004 John Wiley & Sons, Ltd. [source] Effect of Angular Error on Tissue Doppler Velocities and StrainECHOCARDIOGRAPHY, Issue 7 2003Camilla Storaa M.S. One of the major criticisms of ultrasound Doppler is its angle dependency, that is its ability to measure velocity components directly to or from the transducer only. The present article aims to investigate the impact of this angular error in a clinical setting. Apical two- and four-chamber views were recorded in 43 individuals, and the myocardium was marked by hand in each image. We assume that the main direction of the myocardial velocities is longitudinal and correct for the angular error by backprojecting measured velocities onto the longitudinal direction drawn. Strain was calculated from both corrected and uncorrected velocities in 12 segments for each individual. The results indicate that the difference between strain values calculated from corrected and uncorrected velocities is insignificant in 5 segments and within a decimal range in 11 segments. The biggest difference between measured and corrected strain values was found in the apical segments. Strain is also found to be more robust against angular error than velocities because the difference between corrected and uncorrected values is smaller for strain. Considering that there are multiple sources of noise in ultrasound Doppler measurements, the authors conclude that the angular error has so little impact on longitudinal strain that correction for this error can safely be omitted. (ECHOCARDIOGRAPHY, Volume 20, October 2003) [source] Thermal Shock Damage of a 3D-SiC/SiC Composite,ADVANCED ENGINEERING MATERIALS, Issue 11 2005S. Wu Thermal shock of a three-dimensional (3D) SiC/SiC composite prepared by chemical vapor infiltration (CVI) process was conducted using water quenched method. Thermal shock damage of the composite was assessed by SEM characterization and measurement mechanical properties using three-point flexure after quenching. After quenched from 1200°C to 25°C water for 100 cycles, the composite retained 80% of the original flexural strength in the longitudinal direction while cracked through the width direction. Thermal shock damage of the composite was analyzed by thermal stress analysis based on the braiding structure of the composite as well as the distribution and shape of flaws referred to residual pores in the matrix. The braided structure and the dimension difference resulted in the anisotropy of mechanical properties and the matrix pores configuration of the composite, which led to the thermal shock damage anisotropy of the composite. [source] A spline strip kernel particle method and its application to two-dimensional elasticity problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2003K. M. Liew Abstract In this paper we present a novel spline strip kernel particle method (SSKPM) that has been developed for solving a class of two-dimensional (2D) elasticity problems. This new approach combines the concepts of the mesh-free methods and the spline strip method. For the interpolation of the assumed displacement field, we employed the kernel particle shape functions in the transverse direction, and the B3 -spline function in the longitudinal direction. The formulation is validated on several beam and semi-infinite plate problems. The numerical results of these test problems are then compared with the existing solutions obtained by the exact or numerical methods. From this study we conclude that the SSKPM is a potential alternative to the classical finite strip method (FSM). Copyright © 2003 John Wiley & Sons, Ltd. [source] Unequally spaced non-periodic B-spline finite strip methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 1 2003Chang-Koon Choi Abstract The unequally spaced non-periodic B-spline finite strip method (FSM) is presented. The motivation to investigate the irregularly spaced interior nodes in the longitudinal direction of strip is to generalize the concept of non-periodic B-spline FSM and to improve the general accuracy of the stress evaluation in the region of high stress gradients. In the present paper, the unequally spaced non-periodic B3-spline series with multiple knots at the boundary are introduced for the interpolation of displacement and description of geometry in the formulation of isoparametric spline FSM. The use of multiple knots at the boundary makes the shape function satisfy the Kronecker delta properties at the boundary. The unequally spaced B-spline FSM is applied to the stress-reduced shell problem with six degrees of freedom per node. The main purpose of this study is to find a way of ensuring that the geometry of strip is appropriately approximated when the interior nodes of the strip are not regularly spaced along the longitudinal direction. Some numerical results have been compared with those of the previous studies to evaluate the accuracy and efficiency of this method. Copyright © 2003 John Wiley & Sons, Ltd. [source] Acrylonitrile,butadiene rubber/reclaimed rubber,nylon fiber compositeADVANCES IN POLYMER TECHNOLOGY, Issue 4 2001T. D. Sreeja The effect of diphenylmethane diisocyanate (MDI),polyethyleneglycol (PEG) resin on the cure characteristics and mechanical properties of nitrile rubber/whole tyre reclaim,short nylon fiber composite,was studied. At a constant loading of 5 phr, the resin composition was varied. The minimum torque and (maximum , minimum) torque increased with isocyanate concentration. Scorch time and cure time showed a reduction on introduction of bonding agent. Properties like tensile strength, tear strength, and abrasion resistance increased with increase in MDI/PEG ratio, and these properties are higher in the longitudinal direction of fiber orientation. Compression set increased with isocyanate concentration and the resilience remain unchanged. © 2001 John Wiley & Sons, Inc. Adv Polym Techn 20: 281,288, 2001 [source] Effects of curing systems and polysulfonamide pulp on the curing characteristics, mechanical properties, and swelling behavior of ethylene,propylene,diene elastomer compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2010Xiaolong Jia Abstract The effects of three curing systems and polysulfonamide (PSA) pulp on the curing characteristics, mechanical properties, and swelling behavior of ethylene,propylene,diene elastomer (EPDM) composites were investigated. The maximum torque value and the optimum curing time were highest for EPDM composites cured with a peroxide system, and they were closely followed by those cured with a sulfur system. In comparison with those cured with peroxide and phenolic resin systems, EPDM composites cured with the sulfur system showed higher mechanical properties and dimensional stability. With increasing PSA pulp content, the maximum torque value of the EPDM composites increased, whereas the optimum curing time of the composites decreased. The orientation percentage of the PSA pulp in the EPDM composites was maximum at 30 phr pulp, as determined from green strength measurements. In the longitudinal direction along which the pulp was oriented, the EPDM composites showed higher tensile strength as well as lower elongation and swelling ratios. Also, with increasing PSA pulp content, the tensile strength of the EPDM composites decreased up to 10 phr pulp and subsequently increased, whereas the elongation and swelling ratio of the EPDM composites decreased linearly. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Quantity and Quality of Trabecular Bone in the Femur Are Enhanced by a Strongly Anabolic, Noninvasive Mechanical InterventionJOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2002Clinton Rubin Ph.D. Abstract The skeleton's sensitivity to mechanical stimuli represents a critical determinant of bone mass and morphology. We have proposed that the extremely low level (<10 microstrain), high frequency (20-50 Hz) mechanical strains, continually present during even subtle activities such as standing are as important to defining the skeleton as the larger strains typically associated with vigorous activity (>2000 microstrain). If these low-level strains are indeed anabolic, then this sensitivity could serve as the basis for a biomechanically based intervention for osteoporosis. To evaluate this hypothesis, the hindlimbs of adult female sheep were stimulated for 20 minutes/day using a noninvasive 0.3g vertical oscillation sufficient to induce approximately 5 microstrain on the cortex of the tibia. After 1 year of stimulation, the physical properties of 10-mm cubes of trabecular bone from the distal femoral condyle of experimental animals (n = 8) were compared with controls (n = 9), as evaluated using microcomputed tomography (,CT) scanning and materials testing. Bone mineral content (BMC) was 10.6% greater (p < 0.05), and the trabecular number (Tb.N) was 8.3% higher in the experimental animals (p < 0.01), and trabecular spacing decreased by 11.3% (p < 0.01), indicating that bone quantity was increased both by the creation of new trabeculae and the thickening of existing trabeculae. The trabecular bone pattern factor (TBPf) decreased 24.2% (p < 0.03), indicating trabecular morphology adapting from rod shape to plate shape. Significant increases in stiffness and strength were observed in the longitudinal direction (12.1% and 26.7%, respectively; both, p < 0.05), indicating that the adaptation occurred primarily in the plane of weightbearing. These results show that extremely low level mechanical stimuli improve both the quantity and the quality of trabecular bone. That these deformations are several orders of magnitude below those peak strains which arise during vigorous activity indicates that this biomechanically based signal may serve as an effective intervention for osteoporosis. [source] Effect of lateral target motion on image registration accuracy in CT-guided helical tomotherapy: A phantom studyJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 3 2010J Medwig Summary Optimisation of imaging modes for kilovoltage CT (kVCT) used for treatment planning and megavoltage CT (MVCT) image guidance used in ungated helical tomotherapy was investigated for laterally moving targets. Computed tomography images of the QUASARÔ Respiratory Motion Phantom were acquired without target motion and for lateral motion of the target, with 2-cm peak-to-peak amplitude and a period of 4 s. Reference kVCT images were obtained using a 16-slice CT scanner in standard fast helical CT mode, untagged average CT mode and various post-processed 4D-CT modes (0% phase, average and maximum intensity projection). Three sets of MVCT images with different inter-slice spacings of were obtained on a Hi-Art tomotherapy system with the phantom displaced by a known offset position. Eight radiation therapists performed co-registration of MVCT obtained with 2-, 4- and 6-mm slice spacing and kVCT studies independently for all 15 CT imaging combinations. In the investigated case, the untagged average kVCT and 4-mm slice spacing for the MVCT yielded more accurate registration in the transverse plane. The average residual uncertainty of this combination of imaging procedures was 0.61 ± 0.16 mm in the longitudinal direction, 0.45 ± 0.14 mm in the anterior,posterior direction and insignificant in the lateral direction. Manual registration of MVCT,kVCT study pairs is necessary to account for a target in significant lateral motion with respect to bony structures. [source] Biomechanics of Diabetic BladdersLUTS, Issue 2009Chung Cheng WANG Objectives: Biomechanics is the mechanics applied to biology and we hereby review bladder biomechanics in diabetic bladder dysfunction. Methods: The important mechanical properties of bladder tissue include the stress-strain relationship, viscoelasticity and active contraction. Using biaxial mechanical testing methods, the diabetic bladders exhibited non-linear stress-strain mechanical relationships with increasing stiffness at higher stretches in both circumferential and longitudinal directions. Results: The diabetic bladders showed mechanical anisotropy with a greater compliance in the circumferential direction than in the longitudinal direction. The time-course study suggested that diuresis mainly contributed to the "early" changes of the mechanical properties with "late" changes induced by other diabetic effects. Conclusion: The biomechanical study of the urinary bladder has offered a novel understanding of the pathophysiology of diabetic cystopathy and we believe the collaboration of urology and engineering will contribute greatly to the treatment of diabetic bladder dysfunction in the future. [source] Longitudinal and Radial Gradients of PO2 in the Hamster Cheek Pouch MicrocirculationMICROCIRCULATION, Issue 3 2008Helena Carvalho ABSTRACT Objectives: The aim of this study was to determine longitudinal and radial gradients in oxygen tension (PO2) in microvessels of the hamster cheek pouch. Methods: We measured PO2 using the phosphorescence-quenching method in two orders of arterioles (45.8 ± 5.5 and 19.9 ± 1.8 , m diameter), capillaries, and two orders of venules (50.5 ± 3.4 and 21.4 ± 2.0 , m diameter) in order to determine the longitudinal PO2 gradient. At the arteriolar and venular sites, we also measured PO2 at four different sites for an analysis of radial PO2 gradients: centerline, inside wall (larger arteriole and venule only), outside wall, and interstitium. We used 10 hamsters weighing 115 ± 27 g anesthetized with pentobarbital intraperitoneally and maintained with alpha-chloralose intravenously. The cheek pouch was everted and a single-layered preparation was studied by intravital microscopy. Albumin-bound Pd-porphyrin was infused into the circulation and excited by flash illumination at 10 Hz, with a rectangular diaphragm limiting the excitation field to 5 × 25 , m. Results: In the longitudinal direction, intravascular PO2 decreased significantly (P < 0.01) from large arterioles (39.5 ± 2.3 mmHg) to small arterioles (32.2 ± 0.3 mmHg), then to capillaries (30.2 ± 1.8 mmHg), and on to small venules (27.3 ± 2.1 mmHg) and large venules (25.5 ± 2.2 mmHg). In the radial direction, PO2 decreased significantly (P < 0.01) in and around larger arterioles, and to a lesser extent, around the smaller ones (P < 0.05). There was no significant PO2 gradient, longitudinal or radial, associated with venules. The PO2 difference from the centerline to the outside wall in large arterioles was 8.3 ± 1.4 mmHg, and most of the decline in PO2 in the radial direction was contributed by the intravascular difference (4.7 ± 2.1 mmHg) and only about 1.0 ± 2.7 mmHg by the transmural difference. Conclusions: Our data show that there are large intra-arteriolar radial PO2 gradients, but no large transmural PO2 differences, suggesting that the oxygen consumption of the microvessel wall is not exceptionally high. [source] The effect of angle and oscillation on mucous simulant speed in flexible tubesPHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 3 2005Peter W. van Vliet Abstract Background and Purpose. The aim of this study was to investigate, in a tube model, how the speed of a mucous simulant was influenced by angle and different types of oscillations. Method. Using a repeated-measures study design, the primary outcome measure was the mucous simulant speed calculated from the time taken for the mucous simulant to travel a distance of 10 cm. Ultrasonic gel diluted to a viscosity (113 Poise), approximating human sputum, was introduced into a flexible tube similar in diameter to the human adult trachea. The tube was subjected to discrete angles of 0° and 30°, 60° and 90° downward. Symmetrical oscillation was applied in both the transverse and longitudinal directions with frequencies of 5, 15 and 25 Hz at amplitudes of 1 mm and 2 mm peak-to-peak using a commercially available oscillator. Asymmetrical oscillation was applied using repeated cycles of slow acceleration and fast deceleration in the longitudinal direction at 0° and 30° downward and up a 5° incline using a custom-built apparatus. Results. Each 30° angle increment of the tube from 0° to 90° significantly increased mucous simulant speed (p<0.001). Symmetrical oscillation did not provide an advantage over angle in terms of mucous simulant speed; however, asymmetrical oscillation increased mucous simulant speed beyond that caused by angle for all angles tested (p<0.001) and was able to drive mucous simulant up a small incline (5°) in this tube model. It was found that certain types of longitudinal oscillation elongated the mucous simulant. Conclusions. The present study supports the use of gravity to assist in secretion clearance. Asymmetrical oscillation is a novel technique which warrants further investigation. Copyright © 2005 John Wiley & Sons, Ltd. [source] Micro- and macrorheological properties of polypropylene-polyoxymethylene-copolyamide mixture meltsPOLYMER ENGINEERING & SCIENCE, Issue 6 2001M. V. Tsebrenko The influence of polyoxymethylene (POM) additives on micro- and macrorheological properties of polypropylene-copolyamide (PP/CPA) mixture melts with the PP/CPA ratios of 40/60 and 20/80 wt% was investigated. We have shown that the microrheological processes such as deformation of dispersed polymer droplets and formation of liquid polymer streams, coalescence of these streams along the longitudinal direction, migration, and fracture of the liquid streams into droplets can be controlled by addition of a third component that may interact with CPA in a specific manner. The ternary mixture melt viscosity was greater than that of the binary mixture melt viscosity. The degree of viscosity increase depended upon the composition of the binary mixture, the value of shear stress, and POM content. This dependence may be explained by formation of hydrogen bonds between POM and CPA macromolecules. The addition of POM improved the specific PP fiber formation in the matrix of CPA. The latter is valid even for a composition (PP/CPA ratio is 40/60) close to phase inversion. POM migration toward the walls of the forming die occurred in the flow of the ternary polymer mixture melts. For the purpose of realizing the specific fiber formation during the processing of the above mentioned mixtures we recommend an addition of 5% to 10% of POM. [source] Molecular orientation, crystallinity, and flexural modulus correlations in injection molded polypropylene/talc compositesPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 5 2010Marcia Cristina Branciforti Abstract In order to promote better understanding of the structure-mechanical properties relationships of filled thermoplastic compounds, the molecular orientation and the degree of crystallinity of injection molded talc-filled isotactic polypropylene (PP) composites were investigated by X-ray pole figures and wide-angle X-ray diffraction (WAXD). The usual orientation of the filler particles, where the plate planes of talc particles are oriented parallel to the surface of injection molding and influence the orientation of the , -PP crystallites was observed. The PP crystallites show bimodal orientation in which the c - and a*-axes are mixed oriented to the longitudinal direction (LD) and the b -axis is oriented to the normal direction (ND). It was found that the preferential b -axis orientation of PP crystallites increases significantly in the presence of talc particles up to 20,wt% in the composites and then levels-off at higher filler content. WAXD measurements of the degree of crystallinity through the thickness of injection molded PP/talc composites indicated an increasing gradient of PP matrix crystallinity content from the core to the skin layers of the molded plaques. Also, the bulk PP crystallinity content of the composites, as determined by DSC measurements, increased with talc filler concentration. The bulk crystallinity content of PP matrix and the orientation behavior of the matrix PP crystallites and that of the talc particles in composites are influenced by the presence of the filler content and these three composite's microstructure modification factors influence significantly the flexural moduli and the mechanical stiffness anisotropy data (ELD/ETD) of the analyzed PP/talc composites. Copyright © 2009 John Wiley & Sons, Ltd. [source] Developmental reorientation of transverse cortical microtubules to longitudinal directions: a role for actomyosin-based streaming and partial microtubule-membrane detachmentTHE PLANT JOURNAL, Issue 1 2008Frank Sainsbury Summary Transversely oriented cortical microtubules in elongating cells typically reorient themselves towards longitudinal directions at the end of cell elongation. We have investigated the reorientation mechanism along the outer epidermal wall in maturing leek (Allium porrum L.) leaves using a GFP-MBD microtubule reporter gene and fluorescence microscopy. Incubating leaf segments for 14,18 h with the anti-actin or anti-actomyosin agents, 20 ,m cytochalasin D or 20 mm 2,3-butanedione monoxime, inhibited the normal developmental reorientation of microtubules to the longitudinal direction. Observation of living cells revealed a small subpopulation of microtubules with their free ends swinging into oblique or longitudinal directions, before continuing to assemble in the new direction. Electron microscopy confirmed that longitudinal microtubules are partly detached from the plasma membrane. Incubating leaf segments with 0.2% 1°-butanol, an activator of phospholipase D, which has been implicated in plasma membrane,microtubule anchoring, promoted the reorientation, presumably by promoting microtubule detachment from the membrane. Stabilizing microtubules with 10 ,m taxol also promoted longitudinal orientation, even in the absence of cytoplasmic streaming. These results were consistent with confocal microscopy of live cells before and after drug treatments, which also revealed that the slow (days) global microtubule reorientation is superimposed over short-term (hours) regional cycling in a clockwise and an anti-clockwise direction. We propose that partial detachment of transverse microtubules from the plasma membrane in maturing cells exposes them to hydrodynamic forces of actomyosin-driven cytoplasmic streaming, which bends or shifts pivoting microtubules into longitudinal directions, and thus provides an impetus to push microtubule dynamics in the new direction. [source] Aircraft type-specific errors in AMDAR weather reports from commercial aircraftTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 630 2008C. Drüe Abstract AMDAR (Aircraft Meteorological DAta Relay) automated weather reports from commercial aircraft provide an increasing amount of input data for numerical weather prediction models. Previous studies have investigated the quality of AMDAR data. Few of these studies, however, have revealed indications of systematic errors dependent upon the aircraft type. Since different airlines use different algorithms to generate AMDAR reports, it has remained unclear whether a dependency on the aircraft type is caused by physical properties of the aircraft or by different data processing algorithms. In the present study, a special AMDAR dataset was used to investigate the physical type-dependent errors of AMDAR reports. This dataset consists of AMDAR measurements by Lufthansa aircraft performing over 300 landings overall at Frankfurt Rhein/Main (EDDF/FRA) on 22 days in 2004. All of this data has been processed by the same software, implying that influences from different processing algorithms should not be expected. From the comparison of single descents to hourly averaged vertical profiles, it is shown that temperature measurements by different aircraft types can have systematic differences of up to 1 K. In contrast, random temperature errors of most types are estimated to be less than 0.3 K. It is demonstrated that systematic deviations in AMDAR wind measurements can be regarded as an error vector, which is fixed to the aircraft reference system. The largest systematic deviations in wind measurements from different aircraft types (more than 0.5 m s,1) were found to exist in the longitudinal direction (i.e. parallel to the flight direction). Copyright © 2008 Royal Meteorological Society [source] Steer stress levels during long distance transport throughout the year in JapanANIMAL SCIENCE JOURNAL, Issue 4 2008Toshie ISHIWATA ABSTRACT The objective of this study was to investigate transportation conditions and behavioral and physiological responses of beef steers to long distance commercial transport throughout the year Japan. Japanese Black × Holstein steers (7.9 ± 0.6 months of age; 320.0 ± 19.0 kg) were transported by truck in spring (n = 8), summer (n = 5), autumn (n = 8) and winter (n = 5). Transport distances (time) were 1020.6 km (25 h including lairage periods): 615.4 km (6.4 h) on expressways, 163.2 km (3.7 h) on arterial roads and 242.0 km (10.5 h) by ferry. The space allowance of the truck was about 1.6 m2/head in all seasons. Internal temperatures of the truck were 14.7 ± 4.7°C in spring, 27.9 ± 2.6°C in summer, 24.4 ± 2.8°C in autumn and 9.2 ± 4.3°C in winter. Although internal noise and airflow velocity of the truck were louder and greater while moving on expressways (101.1 ± 8.3 dB and 1.50 ± 1.50 m/s) than on arterial roads (92.0 ± 15.2 dB and 1.32 ± 1.41 m/s) (both P < 0.05), more steers lay down while moving on expressways (P < 0.001). Blood glucose, plasma cortisol, and serum triiodothyronine (T3) concentrations and ALT activity were higher in spring (all P < 0.05). This could be explained by that vibration acceleration (m/s2) of the truck in the longitudinal direction was greater in spring (,0.19 ± 0.43) than in the other seasons (,0.14 ± 0.09 in summer, ,0.15 ± 0.20 in autumn and ,0.15 ± 0.13 in winter) (all P < 0.05). Heart rate, serum concentrations of T3, total cholesterol, total protein, and AST and ALT activities were higher just after transport than 1 week after transport (all P < 0.05). However, transport stress should be not severe, since no difference between before and after transport was shown on concentrations of plasma cortisol, blood lactate and serum NEFA, serum triglyceride and serum pH and liveweight. [source] Einwirkungen nach DIN-Fachbericht 101BETON- UND STAHLBETONBAU, Issue 8 2004Lothar Weinreich Dipl.-Ing. Nach der Einführung der DIN-Fachberichte sind alle Bauwerksentwürfe nach dem neuen Regelwerk zu bearbeiten. Der Beitrag beschreibt, in welchen wesentlichen Punkten sich Änderungen bei der Entwurfsbearbeitung gegenüber dem bisherigen Vorgehen ergeben. Für die Vorberechnung von Massivbrücken in Längsrichtung werden die maßgebenden Einwirkungen nach altem und neuem Vorschriftenwerk gegenübergestellt. Es wird außerdem gezeigt, daß die Neuerungen bei den anzusetzenden Einwirkungen in einigen Fällen Änderungen bei den bislang gewählten Bauwerkssystemen und -abmessungen erforderlich machen. Die gegenüber einer Bearbeitung nach DIN-Normen besonders zu beachtenden Punkte werden zusammengestellt. Actions according to DIN-Fachbericht 101: Effects on the Design of Concrete Road Bridges After the introduction of the DIN-Fachberichte all concept designs have to follow the new code of practice. This article describes in which the essential points there are modifications in the concept design compared to the previous actions. For the precalculation of concrete bridges for longitudinal direction the essential actions according to old and new code of practice are compared. It is shown that the innovations of the calculated actions in some cases can make changes in the building structure and the dimension necessary as well. [source] Synthesis of Anatase TiO2 Nanoparticles with ,-Cyclodextrin as a Supramolecular ShellCHEMISTRY - AN ASIAN JOURNAL, Issue 5 2006Landong Li Abstract We report a novel, green hydrothermal-synthesis route to well-dispersed anatase TiO2 nanoparticles with particle sizes of 9,16,nm in the presence of ,-CD (,-cyclodextrin). During the synthesis process, the CD-containing synthesis mixture assembled in both longitudinal and latitudinal directions. Driven by the interaction between molecules, the ,-CDs assembled in the longitudinal direction to form long-chain compounds, whereas in the latitudinal direction, they tended to form regular aggregates through coordination with the Ti species from the hydrolysis of tetrabutyl titanate. In view of the effect of the coordination and the steric hindrance of ,-CDs as a supramolecular shell, homogeneous nuclei and slow growth of TiO2 crystals during the synthesis process was observed, which was responsible for the formation of uniform TiO2 nanoparticles. The low ,-CD dosage and the high product yield (>90,%) demonstrated well the potential of this synthesis route in the large-scale industrial production of anatase nanoparticles. [source] A new non-invasive ultrasonic method for simultaneous measurements of longitudinal and radial arterial wall movements: first in vivo trialCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 5 2003Magnus Persson Summary During recent years, the radial movement of the arterial wall has been extensively studied, and measurements of the radial movement are now an important tool in cardiovascular research for characterizing the mechanical properties of the arterial wall. In contrast, the longitudinal movement of vessels has gained little or no attention as it has been presumed that this movement is negligible. With modern high-resolution ultrasound, it can, however, be seen that the intima-media complex of the arterial wall moves not only in the radial direction, but also in the longitudinal direction during pulse-wave propagation. This paper describes a new non-invasive ultrasonic method that is able to measure simultaneously two dimensionally arterial vessel wall movements. The method is demonstrated in a limited in vivo trial. Results from the in vivo trial show that, apart from the well-known radial movement, there is a distinct longitudinal movement in the human common carotid artery with, in this case, the intima-media complex moving substantially as compared with the region of the tunica adventitia. Two-dimensional evaluation of the vessel-wall movements, taking not only the radial movement, but also the longitudinal movement into account, may provide novel information of importance in the evaluation of vessel-wall function. [source] Biomechanics of Diabetic BladdersLUTS, Issue 2009Chung Cheng WANG Objectives: Biomechanics is the mechanics applied to biology and we hereby review bladder biomechanics in diabetic bladder dysfunction. Methods: The important mechanical properties of bladder tissue include the stress-strain relationship, viscoelasticity and active contraction. Using biaxial mechanical testing methods, the diabetic bladders exhibited non-linear stress-strain mechanical relationships with increasing stiffness at higher stretches in both circumferential and longitudinal directions. Results: The diabetic bladders showed mechanical anisotropy with a greater compliance in the circumferential direction than in the longitudinal direction. The time-course study suggested that diuresis mainly contributed to the "early" changes of the mechanical properties with "late" changes induced by other diabetic effects. Conclusion: The biomechanical study of the urinary bladder has offered a novel understanding of the pathophysiology of diabetic cystopathy and we believe the collaboration of urology and engineering will contribute greatly to the treatment of diabetic bladder dysfunction in the future. [source] The effect of angle and oscillation on mucous simulant speed in flexible tubesPHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 3 2005Peter W. van Vliet Abstract Background and Purpose. The aim of this study was to investigate, in a tube model, how the speed of a mucous simulant was influenced by angle and different types of oscillations. Method. Using a repeated-measures study design, the primary outcome measure was the mucous simulant speed calculated from the time taken for the mucous simulant to travel a distance of 10 cm. Ultrasonic gel diluted to a viscosity (113 Poise), approximating human sputum, was introduced into a flexible tube similar in diameter to the human adult trachea. The tube was subjected to discrete angles of 0° and 30°, 60° and 90° downward. Symmetrical oscillation was applied in both the transverse and longitudinal directions with frequencies of 5, 15 and 25 Hz at amplitudes of 1 mm and 2 mm peak-to-peak using a commercially available oscillator. Asymmetrical oscillation was applied using repeated cycles of slow acceleration and fast deceleration in the longitudinal direction at 0° and 30° downward and up a 5° incline using a custom-built apparatus. Results. Each 30° angle increment of the tube from 0° to 90° significantly increased mucous simulant speed (p<0.001). Symmetrical oscillation did not provide an advantage over angle in terms of mucous simulant speed; however, asymmetrical oscillation increased mucous simulant speed beyond that caused by angle for all angles tested (p<0.001) and was able to drive mucous simulant up a small incline (5°) in this tube model. It was found that certain types of longitudinal oscillation elongated the mucous simulant. Conclusions. The present study supports the use of gravity to assist in secretion clearance. Asymmetrical oscillation is a novel technique which warrants further investigation. Copyright © 2005 John Wiley & Sons, Ltd. [source] Developmental reorientation of transverse cortical microtubules to longitudinal directions: a role for actomyosin-based streaming and partial microtubule-membrane detachmentTHE PLANT JOURNAL, Issue 1 2008Frank Sainsbury Summary Transversely oriented cortical microtubules in elongating cells typically reorient themselves towards longitudinal directions at the end of cell elongation. We have investigated the reorientation mechanism along the outer epidermal wall in maturing leek (Allium porrum L.) leaves using a GFP-MBD microtubule reporter gene and fluorescence microscopy. Incubating leaf segments for 14,18 h with the anti-actin or anti-actomyosin agents, 20 ,m cytochalasin D or 20 mm 2,3-butanedione monoxime, inhibited the normal developmental reorientation of microtubules to the longitudinal direction. Observation of living cells revealed a small subpopulation of microtubules with their free ends swinging into oblique or longitudinal directions, before continuing to assemble in the new direction. Electron microscopy confirmed that longitudinal microtubules are partly detached from the plasma membrane. Incubating leaf segments with 0.2% 1°-butanol, an activator of phospholipase D, which has been implicated in plasma membrane,microtubule anchoring, promoted the reorientation, presumably by promoting microtubule detachment from the membrane. Stabilizing microtubules with 10 ,m taxol also promoted longitudinal orientation, even in the absence of cytoplasmic streaming. These results were consistent with confocal microscopy of live cells before and after drug treatments, which also revealed that the slow (days) global microtubule reorientation is superimposed over short-term (hours) regional cycling in a clockwise and an anti-clockwise direction. We propose that partial detachment of transverse microtubules from the plasma membrane in maturing cells exposes them to hydrodynamic forces of actomyosin-driven cytoplasmic streaming, which bends or shifts pivoting microtubules into longitudinal directions, and thus provides an impetus to push microtubule dynamics in the new direction. [source] | ||||||||||||||||||||||