Value Of Vertical Displacement Research Articles

Determination of parameters of low-frequency internal waves in the coastal zone of a fringing sea using field measurements and basing on the nonlinear theory

A method is presented to determine the quadratic nonlinearity parameter and amplitude of low-frequency internal gravity waves in the coastal zone of a fringing sea, based upon their propagation rate dependence on local value of pycnocline vertical displacement produced by the waves. To test the method, the internal wave field observations in the coastal zone of the Sea of Japan are used. The testing results show that the internal wave parameters calculated using the proposed method and the experimental data are in a good agreement with those calculated from theoretical formulas.

Sea level change in the Gulf of Thailand from GPS-corrected tide gauge data and multi-satellite altimetry

Investigation of long-term tidal data and short-term altimetry measurements reveals that sea level in the Gulf of Thailand is rising significantly faster than global average rates. Upward land motion detected from repeated precise GPS campaign measurements is used to correct the apparent sea level change from tide gauge, yielding absolute long-term trends as follows: Sattahip (1942–2004) 5.0 ± 1.3 mm/yr, Ko Sichang (1940–1999) 4.5 ± 1.3 mm/yr and Ko Mattaphon (1964–2004) 4.4 ± 1.1 mm/yr. Dual-crossover minimization of multi-mission altimetry data covering the 1993–2009 period reveals the following absolute sea level rates: Sattahip 4.8 ± 0.7 mm/yr, Ko Sichang 5.8 ± 0.8 mm/yr, Ko Lak 3.6 ± 0.7 mm/yr and Ko Mattaphon 3.2 ± 0.7 mm/yr. In other parts of the Gulf, the 1993–2009 rising rates are also in the range of 3 to 5.5 mm/yr. In the entire Gulf we don't find any evidence of sea level falling. At Ko Lak where the collocation of Topex-class altimetry ground track and the tidal station is extremely good, vertical land motion derived from the difference of sea level change rates detected by altimetry and tidal data is used to correct the apparent rate, yielding an absolute long-term (1940–2004) rate of 3.0 ± 1.5 mm/yr. The differences between the altimetry-based rates and the absolute tide gauge sea level trends can be explained by interannual variations like ENSO and decadal variations due to solar activity and lunar nutation. Post-2004 tidal data have been treated separately in our study because reliable values of region-wide vertical co-seismic displacements and post-seismic velocities caused by the 2004 Mw9.2 Sumatra-Andaman earthquake are still not accurately known. Exclusion of these data will not significantly change the determined long-term absolute sea level change rates because of the relatively short time span of post-earthquake sea level data compared to the complete tidal record. The impact of fast rising sea level combined with high rates of post-seismic downward crustal motions as indicated by GPS data makes coastal areas and river estuaries along the Gulf of Thailand highly vulnerable to flooding, particularly the low-lying city of Bangkok.

Optimization of flexible beams

We consider the optimal design problem for cantilever beams of variable rigidity loaded at the free end by an arbitrary transverse force. The value of the cantilever free end vertical displacement serves as the optimality criterion, and the distribution of the cantilever thicknesses (cross-sections) is usually used as the design variable. We present results of an asymptotic analysis and a numerical solution of the optimization problem and discuss specific features of the formation of optimal solutions under nonlinear bending.

Structural Line Shape and Stress Analysis in the Construction of Kaziwan Bridge

Cantilever installation is a construction method of which is often used in the construction of Concrete Oblique-pulling truss bridge. For ensuring the safety of construction process, the structural line shape and stress under different construction phases of the bridge were tested. Contrastive analysis between the testing results and the calculating results was carried on in different construction phases. The results showed the testing values of vertical displacement is smaller than the calculating values because the actual stiffness of the structure is bigger than the theory stiffness. But the stress of key section’s stress of the truss bridge in the whole construction phases agreed pretty well between the testing results and the calculating results. The maximal cantilever length phase to entire bridge closure phase is the most disadvantageous state in the whole construction process.

Analysis of polymerization time on abrasive wear of dental resins

An evaluation was made of the abrasive wear of six composite thermofixed dental resins subjected to different polymerization times. The method of evaluation was based on sharpness measurements to quantify the abrasive wear resistance of the resins. To this end, a test bench was built, consisting of a rotating porcelain cylinder that wears out a resin-coated cylinder placed above it, thus causing vertical displacement of the contact as the wear progresses. The values of vertical displacement, i.e., the input variables, were read and recorded by means of a computer program to obtain the sharpness values. These data indicated that the resins displayed different behaviors as a function of the polymerization times applied, reinforcing the importance of using a practical and rapid method of analysis in order to ensure that the behavior of new materials is fully understood before they are launched on the market.

The Muzaffarabad, Pakistan, earthquake of 8 October 2005: surface faulting, environmental effects and macroseismic intensity

Abstract The Mw 7.6 Muzaffarabad earthquake of 8 October 2005, occurred on a lateral equivalent of the main ramp of the Hymalaia frontal thrust, and is the result of the collision tectonics between the Indian and Eurasian plates. The epicentre was located near the town of Basantkot (Muzaffarabad), and the focal depth was about 13 km. The Muzaffarabad earthquake provides unequivocal evidence about the localization of severe damage, intense ground shaking and secondary environmental effects near the surface expression of the source fault. We analyse its nature, and impact on man-made structures and the physical environment, on the basis of a detailed survey and macroseismic study of the affected areas conducted by the Micro Seismic Studies Programme (MSSP) Team (Ishfaq Ahmad Research Laboratories, Pakistan Atomic Energy Commission) immediately after the mainshock, assisted by a careful review of the subsequent data and literature. In the course of the field survey, the displacement and surface expression of the causative fault, and accompanying secondary environmental effects were observed at a number of places along a capable thrust fault structure. We refer to this structure as the Kashmir Thrust (KT) capable fault following the terminology of local research geologists in Pakistan; the seismological evidence of this structure is already known in the literature as the Indus–Kohistan Seismic Zone. A complex, clearly segmented, at least 112-km-long surface rupture was mapped along the KT. The maximum values of vertical displacement (on the order of 4 to 7 m) were observed mainly between Muzaffarabad and Balakot, along the central segment of the rupture (52 km) associated with maximum slip at depth and a major portion of the energy release. Both the NW Alai segment (38 km) and SE Bagh segment (22 km) are characterized by scattered minor surface ruptures with a few centimetres of displacement, accompanied by extensive surface cracking, landslides and severe damage, concentrated in a narrow belt along the fault trace. A maximum intensity of XI on the Modified Mercalli Intensity (MMI) scale and on the Environmental Seismic Intensity scale (ESI 2007) was recorded in the epicentral area between Muzaffarabad and Balakot. Extremely severe damage and very important secondary environmental effects in the hanging wall adjacent to the trace of the causative fault plane are mainly due to near-fault strong motion and rupture directivity effects. To our knowledge, this is the first study to present field observations over the whole near-field of the earthquake, and to include the intensity map of the entire meizoseismal region.

Damage Identification in 2D Structures Through Static Response

The local stiffness reduction produced by cracks change the static and dynamic behavior of the structural ele- ments and, by examining this change, crack position and magnitude can be identified. This paper presents a methodology which aim is the detection, location and quantification of the damage through the values of vertical displacements, pro- duced by static loads. With the purpose of establishing the precision of the results obtained in planar structures, numerical simulations were made, analyzing them with the Finite Element Method. Furthermore, two techniques for the detection and damage location are presented. The first one is related to the displacement variation in a damaged structure in relation to the same structure without damage. The second technique is based on the elastic curvature which is computed by means of the Finite Differences Method. The techniques presented are versatile tools, of easy application at work, for structural damage identification.

Wave-impact characteristics of plunging breakers acting on gravel beaches

This paper presents observations of pressure impulses from wave impacts of breaking waves on steep coarse-grained beaches. It builds upon recent investigations on gravel beaches which suggest the wave impact of a plunging breaker is an important process that shapes the morphology of these beaches and that is not taken into account under many modelling frameworks (Pedrozo-Acuña, A., Simmonds, D.J., Chadwick, A.J. and Silva, R., 2007. A numerical–empirical approach for evaluating morphodynamic processes on mixed and gravel beaches. Mar. Geol., 241(1–2): 1–18). Full scale laboratory measurements of induced pressures by plunging breakers acting on gravel beaches are reported showing that these are more significant than those reported for sandy beaches under the forcing of similar wave conditions. Additionally, four different types of pressure-curves are identified and classified in terms of the type of forcing behind its generation. It is shown that measured impact pressures within the gravel beach are a consequence of plunging breakers propagating over the beach profile, with maximum pressure values being up to 4.5 times the quasi-hydrostatic induced pressure for a given wave height. It is demonstrated that the largest measured impacts are not only related to larger values of wave height and vertical displacement of the free surface but also to the wave steepness of the incident wave. Results suggest that between two plunging breakers of the same height, the steeper will produce a stronger wave impact. The plunging of breakers onto a gravel beachface and the ensuing pressure gradients are suggested as a key mechanism for understanding sediment transport and the resulting morphology of gravel beaches.

Mechanical analysis of glulam beams exposed to changing humidity

This study deals with the mechanical analysis of glulam beams during changing relative humidity of the surrounding air. The computational part of the article includes two separate numerical procedures. First, the diffusion equation is solved to determine the temporal and spatial distribution of water content in the cross-section of the beam. The results of the first computational stage are used as the input data for the numerical analysis of mechanical response of the beam. The displacements and stress distribution at some characteristic cross-sections are presented. In the article some experimentally determined values of vertical displacements in the middle of span are shown and compared to the results of numerical analysis.

Evolution of a fault surface from 3D attribute analysis and displacement measurements

A large fault surface evolves by growth and coalescence of numerous segments through time, which results in strong undulations of the principal fault surface. We interpreted a strongly segmented, 13 km long fault using 3D seismic data, and studied the morphology in terms of fault linkage, using curvature, azimuth, and dip attributes. Displacement profiles of two horizons were measured to analyse the different displacement relations and to quantify their variation and dependence on fault morphology. We identified four orders of fault segments over a scale range from a few hundred metres to several kilometres, which evolved during fault growth. The strong changes in orientation of the several segments might result in a heterogeneous small-scale fracture distribution and different fault drag geometries. Displacement measurements on the undulated fault surface indicate a strong variation between real, vertical, and horizontal displacement values. However, the commonly used throw values lead to a smoothing of the real displacement curves and to an underrepresentation of their values, and therefore cannot show a triangular shape that is typically identified from ruptures fault surfaces of earthquake processes. Therefore, for any kind of fault analysis care should be taken when using throw as approximation for the real displacement.

Impact of flow distortion corrections on turbulent fluxes estimated by the inertial dissipation method during the FETCH experiment on R/V L'Atalante

The FETCH campaign was for a large part devoted to the measurement and analysis of turbulent fluxes in fetch‐limited conditions. Turbulent measurements were performed on board the R/V L'Atalante, on an ASIS spar buoy and on aircraft. On the R/V L'Atalante, turbulent data were obtained from a sonic anemometer and from a microwave refractometer. The main focus of this paper is to present results of momentum and heat fluxes obtained from the R/V L'Atalante, using the inertial‐dissipation method and taking into account flow distortion effects. Numerical simulations of airflow distortion caused by the ship structure have been performed to correct the wind measurements on the R/V L'Atalante during the FETCH experiment. These simulations include different configurations of inlet velocities and six relative wind directions. The impact of airflow distortion on turbulent flux parameterizations is presented in detail. The results show a very large dependence on azimuth angle. When the ship is heading into the wind (relative wind direction within ±38° of the bow), the airflow distortion leads to an overestimation of the drag coefficient, associated with a wind speed reduction at the sensor location. For relative wind directions of more than ±38° from the bow, flow distortion causes the wind to accelerate at the sensor location, which leads to an underestimate of the drag coefficient. The vertical displacement of the flow streamlines could not be fully established by numerical simulation, but the results are in qualitative agreement with those inferred from the data by prescribing the consistency of momentum flux as a function of azimuth angle. Both show that the vertical elevation of the flow can be considered as constant (1.21 m from numerical simulations) only within about ±20° from bow axis. Values of vertical displacements up to 5 m are found from the data for high wind speeds and beam‐on flows. Our study also shows that the relative contributions of the streamline vertical displacement and the mean wind speed underestimate or overestimate vary significantly with relative wind direction. The relative contribution due to vertical streamline displacement is higher for heat flux than for momentum flux. The consistency of our correction for airflow distortion is assessed by the fact that the correction reduces the standard deviation of the drag coefficient: only if this correction is taken into account, do the curves of the drag coefficient versus wind speed become similar for data corresponding to wind in the bow direction and from the side. When the complete numerical airflow correction is applied to the data set limited to relative wind directions at ±30° from the bow axis, the drag coefficient formula is CD10N × 1000 = 0.56 + 0.063 U10N, for U10N > 6 m s−1. This formula provides CD10N values comparable to the ones found from the ASIS buoy data for wind speeds of about 13 m s−1. They are however smaller by 9% at higher winds (>15 m s−1). This formula is also similar, within a few percent, to the parameterizations of Smith [1980], Anderson [1993], and Yelland et al. [1998]. The exchange coefficient for evaporation is found to be 1.00 × 10−3 on average with a small standard deviation of 0.31 × 10−3. A slight increase of CE10N value with wind speed is, however, observed with a variation of about 20% (0.2 × 10−3) for wind speeds between 6 and 17 m s−1, following CE10N × 1000 = 0.82 + 0.02 U10n, for U10n > 6 m s−1.

Analysis of shear lag and shear deformation effects in laminated composite box beams under bending loads

A method for analyzing the shear lag and shear deformation effects on symmetrically laminated thin-walled composite box beams under bending load is presented. The method is based on the theory of composite laminated plates and is deduced by means of the principle of minimum potential energy, which makes the procedure simple and practical. The formulas given by this method not only satisfy the equilibrium conditions on the cross-section of the thin-walled composite box beams but can be simplified to the known formulas of thin-walled box beams with isotropic materials as well. Finally, an example is given and its numerical results are analyzed and discussed. The values of vertical displacements and ply normal stresses obtained by this paper are compared with those obtained by the finite element method (FEM) or previously published experimental and numerical results, respectively. A comprehensive analysis on the effects of shear lag and shear deformation is given for a simply supported thin-walled composite box beam subjected to a centralized load at mid-span.

GPS positioning as applied to investigation of recent crustal movements

The general goal of the paper is to discuss methodological problems appearing nowadays when geodetic measurements used for geodynamic studies are switched from terrestrial to satellite GPS methods. Assuming that both terrestrial measurements on local geodynamical test fields and GPS positioning will have to be intensively applied during this decade as complementary methods for investigation of recent crustal movements, the paper is aimed at discussion of some aspects of compatibilities and inconsistencies appearing while combining the results of both methods. A serious problem arises while comparing gravity-dependent height differences obtained by precise spirit levelling with those derived from GPS. Considering that terrestrial levelling networks used traditionally for studies of vertical crustal movements will no longer be maintained, a procedure of flexible transition from the old terrestrial levelling to the new GPS-based method is proposed in a form of so called ‘ tailored approach’. A transformation proposal of repeated GPS measurements to the values of horizontal and vertical displacements of the Earth's surface is presented. The method is supported by the results of a GPS field experiment.

Selected Sports Bras: Comparisons of Comfort and Support

This study compared seven sports bras on quantitative and subjective measures of support and comfort for small, medium, and large breasted women during exercise. Fifty-nine subjects representing A, B, C, and D cup sizes were filmed while jogging on a treadmill at 6 mph in each bra style and in the nude condition. The average vertical displacement of the breast relative to the body was calculated for each condition. Subsequently, subjects completed questionnaires after engaging in vigorous exercise in each bra to assess subjectively comfort and support for each of the seven sports bras. Two-way repeated measures ANOVA's and subsequent pairwise comparisons indicated significant differences by bra style in subjective mean comfort scores and a significant interaction between subjects' cup sizes and subjective mean support scores. Pearson product moment correlation coefficients among vertical displacement values, subjective measures of support, and subjective measures of comfort indicated that bras that effectively controlled breast displacement tended to score lower on comfort. There were, however, exceptions to this trend, and no single bra rated well on all three measures of performance.

Use of Referential Coordinates in Deforming Soils

AbstractAnalysis of hydrological processes in deforming soils generally involves use of some form of a referential, or material, coordinate transformation. In the most commonly used of these relationships, there appear two macroscopic soil mass density factors, that associated with the configuration of the soil at a reference time t = 0, and that associated with its configuration at a later (arbitrary) time. In some previous work, the assumption was made that these bulk densities could be evaluated at the same space‐fixed point. In an illustrative application to dual‐energy gamma‐ray data on the swelling of a clay loam during infiltration, this approximation is shown here to predict vertical displacement values that are as much as 7 mm in excess of values obtained without the approximation. Moreover, the approximation fails to satisfy macroscopic mass balance. It is also shown that the direction, downward or upward, of the vertical displacement of macroscopic body‐points depends on the boundary condition used in the integration of the referential coordinate transformation; i.e., depends on whether the integration begins at the soil surface or at a point below the wetting front. Since these two integration pathways are mathematically equivalent, it is argued that a systematic comparison between results obtained using them can serve a useful purpose in detecting occurrences of lateral expansion or systematic errors in the experimental data.

Forecasting of Ekofisk Reservoir Compaction and Subsidence by Numerical Simulation

A finite-element computational procedure for simulating the reservoir compaction and subsidence processes at Ekofisk is described. Data input requirements are considered, and results are presented for selected reservoir management options. Field measurements of subsidence, subsidence rates, and subsidence-bowl profiles are shown to be in good agreement with calculated results.

A finite element model for the analysis of wave induced stresses, displacements and pore pressures in an unsaturated seabed I: theory

This paper presents the theoretical development of the differential equations governing wave induced stresses, displacements and pore pressures in an unsaturated seabed. These governing coupled flow and deformation equations are presented for plane strain conditions subject to a sinusoidal wave loading on the seabed. The finite element formulation of the resulting equations is also presented. The governing flow and deformation equations, reduced by assuming that all variables behave in simple harmonic form, are discretized in one-dimensional vertical space using the Galerkin finite element method. Simple linear two-noded elements are used to which closed form solutions of the element stiffness matrices and load vectors are presented. Solution algorithms for the flow and deformation equations are described. Nodal values of horizontal displacement, vertical displacement and pore water pressure are output in simple harmonic form, as are the total and effective components of stress at the element centroids.

Numerical modelling of a centrifuged embankment on soft clay

Biot coupled consolidation numerical analyses have been applied to a stage-constructed embankment on soft clay in the centrifuge. In the test, the sand embankment was constructed during flight on a clay foundation consisting of an overconsolidated crust overlying a normally consolidated layer. Measurements were taken of pore pressures, dissipation rates, and displacements in the foundation clay. Predictions of these were made using a simple Cam-clay model for the clay and the Cambridge CRISP computer program. A linear elastic idealization was used for the embankment. With some exceptions, pore pressures and dissipation rates were very well predicted, as were maximum values of both horizontal and vertical displacements. However, displacement profiles with depth were not so well predicted. Particular attention is given in the paper to the determination of relevant values of shear modulus G and the difference in behaviour resulting from using constant permeability and permeability varying with void ratio. Key words: embankments, soft clay, centrifuge test, numerical analysis, Biot consolidation, Cam-clay model.

Observation of the lateral fluctuation of the laser beam passing through the atmosphere

Lateral fluctuation of the laser spot formed after passing through a distance of 2.26 km above the sea surface was observed together with the air, the surface water temperatures, and the relative humidity. Our main phenomenalistic findings were as follows: (1) a maximum value of the vertical displacement of the beam spot and that of its time rate were 2.1 m and 0.5 m/min, respectively; (2) the ‘large fluctuation,’ the displacement larger than 10 cm, was likely to occur just before the sunrise and, more remarkably, just after the sunset; (3) in each run of observation the frequency of such a large fluctuation seemed to be correlated with the changes in the air temperature and the relative humidity, and (4) an increment of the temperature gradient corresponding to the maximum displacement of 2.1 m was estimated to be 0.77 deg/m.

Dynamic response of laminated plates to random loading

The subject of this paper is the response of laminated plates in cylindrical bending to random dynamic loading. A random loading is characterized by a weakly stationary stochastic process. The formulae for correlation function (and variance) of vertical displacement of a plate are obtained and the numerical results are provided for the assumed form of the correlation function of a random loading. The effect of the fiber orientation and the correlation parameter of the external loading on the mean-square value of vertical displacement are shown graphically. The results are compared with those obtained using the classical Kirchhoff and Mindlin theory for homogeneous plates.