Preliminary results on a near-real-time rock slope damage monitoring system based on relative velocity changes following the September 5,2022 M_(S) 6.8 Luding,China earthquake

Relative seismic velocity change(dv/v)is important for monitoring changes in subsurface material properties and evaluating earthquake-induced rock slope damage in a geological disaster-prone region.In this paper,we present a rapid damage assessment on three slow-moving rock slopes by measuring dv/v decrease caused by the 2022 M_(S) 6.8 Luding earthquake in Southwest China.By applying the stretching method to the cross-correlated seismic wavefields between sensors installed on each slope,we obtain earthquake-induced dv/v decreases of~2.1%,~0.5%,and~0.2%on three slopes at distances ranging from~86 to~370 km to the epicenter,respectively.Moreover,based on seismic data recorded by 16 sensors deployed on the rock slope at a distance of~370 km away from the epicenter,a localized dv/v decease region was observed at the crest of the slope by calculating the spatial dv/v images before and after the earthquake.We also derive an empirical in situ stress sensitivity of -7.29×10^(-8)/Pa by relating the dv/v change to the measured peak dynamic stresses.Our results indicate that a rapid dv/v assessment not only can help facilitate on-site emergency response to earthquakeinduced secondary geological disasters but also can provide a better understanding of the subsurface geological risks under diverse seismic loadings.

The Effect of the Relative Velocity on Traffic Flow

The optimal velocity model of traffc is extended to take the relative velocity into account. The traffcbehavior is investigated numerically and analytically with this model. It is shown that the car interaction with therelative velocity can effect the stability of the traffic flow and raise critical density. The jamming transition between thefreely moving and jamming phases is investigated with the linear stability analysis and nonlinear perturbation methods.The traffic jam is described by the kink solution of the modified Korteweg-de Vries equation. The theoretical result isin good agreement with the simulation.

Estimation of peak relative velocity and peak absolute acceleration of linear SDOF systems

We have found some mistakes in the article by Jianwei Song et al. （2007）. The revisions are given below：

Rolling velocity and relative motion of particle detector in local granular flow

The velocity of a particle detector in granular flow can be regarded as the combination of rolling and sliding velocities.The study of the contribution of rolling velocity and sliding velocity provides a new explanation to the relative motion between the detector and the local granular flow.In this study,a spherical detector using embedded inertial navigation technology is placed in the chute granular flow to study the movement of the detector relative to the granular flow.It is shown by particle image velocimetry(PIV)that the velocity of chute granular flow conforms to Silbert’s formula.And the velocity of the detector is greater than that of the granular flow around it.By decomposing the velocity into sliding and rolling velocity,it is indicated that the movement of the detector relative to the granular flow is mainly caused by rolling.The rolling detail shown by DEM simulation leads to two potential mechanisms based on the position and drive of the detector.

RELATIVE NONSYMMETRY EFFECTS OF THE SUPER (GENERALIZED) NONLINEAR VELOCITY,TIME OF A PARTICLE AND ITS KINETIC FORMULAE FOR FOLLOWED BODY

In the paper, it has been described the relative nonsymmetry effects of the super (generalized) nonlinear velocity, time of a particle and its kinetic formulae far the followed body when it moves with high velocity. The nonsymmetry effects can explain the problem appearing in the extention of the life time for the secondary cosmic ray, mu mesons; they also can explain the controversial problem who is more young in the famous twin paradox. Finally, the followed body kinetic formulae for the particle have been founded.

Effects of the Reynolds number on a scale-similarity model of Lagrangian velocity correlations in isotropic turbulent flows

A scale-similarity model of a two-point two-time Lagrangian velocity correlation(LVC) was originally developed for the relative dispersion of tracer particles in isotropic turbulent flows(HE, G. W., JIN, G. D., and ZHAO, X. Scale-similarity model for Lagrangian velocity correlations in isotropic and stationary turbulence. Physical Review E, 80, 066313(2009)). The model can be expressed as a two-point Eulerian space correlation and the dispersion velocity V. The dispersion velocity denotes the rate at which one moving particle departs from another fixed particle. This paper numerically validates the robustness of the scale-similarity model at high Taylor micro-scale Reynolds numbers up to 373, which are much higher than the original values(R_λ = 66, 102). The effect of the Reynolds number on the dispersion velocity in the scale-similarity model is carefully investigated. The results show that the scale-similarity model is more accurate at higher Reynolds numbers because the two-point Lagrangian velocity correlations with different initial spatial separations collapse into a universal form compared with a combination of the initial separation and the temporal separation via the dispersion velocity.Moreover, the dispersion velocity V normalized by the Kolmogorov velocity V_η ≡ η/τ_η in which η and τ_η are the Kolmogorov space and time scales, respectively, scales with the Reynolds number R_λ as V/V_η ∝ R_λ^(1.39) obtained from the numerical data.

A Neo Explanation of the"Mass-Velocity Relation

A reinterpretation of the well-known formula of the 'mass-velocity relation' is exactlyderived from a new viewpoint with new concepts, such as the finiteness of the transmitting velocityof force (TVF), effective action, and the coupled effect of the TVF for two EM fields, etc. Then, atrue meaning hidden in the Lorentz factor is exploited : i.e., when a charged particle is moving at aspeed v under an EM field, the effective action exerted on it by the field varies inversely with thespeed ratio β= v / U, where U is the TVF, which probably is equal to the propagation velocity ofEM field. The actual reduction of the effective action gives a false impression of mass gain.Accordingly, it is a major mistake in orientation to ascribe the (genuine) electrodynamics of movingbodies to any observation, or to any motion of an observer, while disregarding the facts of mutualaction.

The Statistical Relation of Shear Velocity with Soil Properties

Shear velocity is an important index for evaluating soil dynamic properties of the site. In this paper, the statistical relation of shear velocity with soil properties is set up by statistical analysis of shear velocities and relevant soil properties measured in Tianjin and Shanghai. The obtained formula has some referential value for the evaluation and classification of the site in offshore areas of China.

Relative energy zero ratio-based approach for identifying pulse-like ground motions

Pulse-like ground motions are capable of inflicting significant damage to structures. Efficient classification of pulse-like ground motion is of great importance when performing the seismic assessment in near-fault regions. In this study, a new method for identifying the velocity pulses is proposed, based on different trends of two parameters: the short-time energy and the short-time zero crossing rate of a ground motion record. A new pulse indicator, the relative energy zero ratio(REZR), is defined to qualitatively identify pulse-like features. The threshold for pulse-like ground motions is derived and compared with two other identification methods through statistical analysis. The proposed procedure not only shows good accuracy and efficiency when identifying pulse-like ground motions but also exhibits good performance for classifying records with high-frequency noise and discontinuous pulses. The REZR method does not require a waveform formula to express and fit the potential velocity pulses;it is a purely signal-based classification method. Finally, the proposed procedure is used to evaluate the contribution of pulse-like motions to the total input energy of a seismic record, which dramatically increases the seismic damage potential.

A WEAKLY NONLINEAR WATER WAVE MODEL TAKING INTO ACCOUNT DISPERSION OF WAVE PHASE VELOCITY

This paper presents a weakly nonlinear water wave model using a mild slope equation and a new explicit formulation which takes into account dispersion of wave phase velocity, approximates Hedges’ (1987) nonlinear dispersion relationship, and accords well with the original empirical formula. Comparison of the calculating results with those obtained from the experimental data and those obtained from linear wave theory showed that the present water wave model considering the dispersion of phase velocity is rational and in good agreement with experiment data.

Gravity, Not Mass Increases with Velocity

There are controversies and misunderstandings with the term “relativistic mass”. So, alternative concepts must be considered. It is postulated herewith that the stronger force required to accelerate an object moving at a faster speed is due to the increase of its inertia. That ensues in a rise in the gravitational force required to pull that object, and thereby brings to an increase in the gravitational constant. In this paper a formula is derived to calculate these variations in the gravitational constant, which is: . This makes the use of the term “relativistic mass” unnecessary.

Phase Velocity and Rest Energy of Schrödinger Equation Seen from Neutrino Oscillations

The phase velocity is discussed using de Broglie relations and Schrödinger equation. We argue that in non-relativistic quantum mechanics the Hamiltonian should be added by a rest-energy term when Schrödinger equation is used to study the interference between particles of different masses. From neutrino oscillation experiments, we find that the phase velocity can be related to a measurable quantity (the flavor transition probability), therefore, the phase factor originated from the rest energy can’t be omitted. Correspondingly, the energy in de Broglie relations should always be total energy rather than kinetic energy, contrary to some textbooks of quantum mechanics.

基于冲刷指数的雨水管渠冲刷淤积分析

流速、雷诺数、充满度等单因素指标虽然与雨水管渠的冲刷和淤积量有一定的关联,但是通过单因素指标不足以全面地判断雨水管道的冲刷和淤积。在起动流速和止动流速的基础上,提出了冲刷指数的概念。结合连续非恒定流不同工况下冲刷和淤积量模拟,计算了流速、雷诺数、充满度、冲刷指数4个因素与冲刷量的灰色关联度,其关联度大小依次为:冲刷指数>雷诺数>充满度>流速。根据不同工况的恒定流模型实验的结果,其关联度大小依次为:冲刷指数>>流速>雷诺数>充满度。可以认为,在恒定流与非恒定流工况下,冲刷量和冲刷指数有显著的强相关性,冲刷指数能代替具体的冲刷量计算实现对冲刷程度和趋势的合理判断。

煤矿井下随掘地震速度分析方法研究

地震波的速度参数贯穿于地震数据的采集、处理和解释的整个过程,速度参数的准确与否决定了最终解释结果的可靠性。煤矿井下随掘地震监测是一种连续采集地震数据的勘探方法,其接收到的数据量巨大,海量的数据量若采用人工处理的方式则无法实现随掘监测的实时性与数据处理的自动化。常规地震数据通过采用交互速度分析的方式得到地震波速度,而随掘地震数据的信噪比较低,没有明显可识别的同相轴。因此,常规地震数据处理采用的交互速度分析方式难以应用于随掘地震数据的处理。介绍了一种煤矿井下随掘地震速度分析方法,以实现随掘速度分析的自动化为目标,探索并研究了速度分析中叠加及相关振幅的不同算法,优选了适用于随掘地震数据的速度分析算法,将不同的叠加及相关振幅算法应用于随掘数据,取得了较好的处理效果,对实际生产中随掘地震数据速度分析提供了一定的借鉴。

Evaluation of gas condensate reservoir behavior using velocity dependent relative permeability during the numerical well test analysis

Gas condensate is one of the most different fluids in reservoir simulation due to retrograde condensation in case of pressure reduction.In this kind of fluids,two phenomena named negative inertia and positive coupling,become significant in the high velocity zone around the wellbore.In this study,a modified black oil simulator is developed that take into account the velocity dependent relative permeability.Against the industrial simulator that assumes linear variation of transmissibilities by pressure,modified black oil nonlinear equations are solved directly without linearization.The developed code is validated by ECLIPSE simulator.The behavior of two real gas condensate fluids,a lean and a rich one,are compared with each other.For each fluid,simulations of PVT experiments are carried out to calculate black oil property applying Coats approach for gas condensate fluids.For both fluids,the proposed models for gas condensate velocity dependent relative permeability show different influence of velocity on relative permeability in the same conditions.Moreover,it is observed that higher flow rate of gas production leads to more condensate production during constant rate well testing.

Cross-Correlation of Station-to-Station Free Surface Elevation Time Series for Breaking Water Waves

Free surface elevation time series of breaking water waves were measured in a laboratory flume. This was done in order to analyze changes in wave characteristics as the waves propagated from deep water to the shore. A pair of parallel- wire capacitive wave gages was used to simultaneously measure free surface elevations at different positions along the flume. One gage was kept fixed near the wave generator to provide a reference while the other was moved in steps of 0.1 m in the vicinity of the break point. Data from these two wave gages measured at the same time constitute station-to-station free surface elevation time series. Fast Fourier Transform (FFT) based cross-correlation techniques were employed to determine the time lag between each pair of the time series. The time lag was used to compute the phase shift between the reference wave gage and that at various points along the flume. Phase differences between two points spaced 0.1 m apart were used to calculate local mean wave phase velocity for a point that lies in the middle. Results show that moving from deep water to shallow water, the measured mean phase velocity decreases almost linearly from about 1.75 m/s to about 1.50 m/s at the break point. Just after the break point, wave phase velocity abruptly increases to a maximum value of 1.87 m/s observed at a position 30 cm downstream of the break point. Thereafter, the phase velocity decreases, reaching a minimum of about 1.30 m/s.

A STUDY OF THE RELATION BETWEEN RIVER REGULATION AND FLOOD CONTROL

Flood control is closely related to the rising level of the upstream. Thechange of the main current and the inshore current velocity is induced by thecompletion of the regulation work. Yet Flood Control Departments pay muchmore attention to the extent,the range and the law of the inshore current velocity increase,especially in the river reaches which have arduous tasks of floodcontrol. Flood Control Departments object to constructing regulation work sucnas groynes,because they have always thought regulation work may lead to theincrease in the inshore current velocity.This paper intends to expound on theinfluences of regulation work on the extent,range and law of the inshore current velocity through analyzing the data obtained from the scale model tests ofthe Jiepai Reach in the middle of the Yangtze River and also discuss the possi-bility of limiting increase of the inshore current velocity through properly ad-justing regulaton work,thus we can correct evaluation of the influence of theriver regulation

上肢加压治疗在预防无运动能力患者经外周静脉穿刺的中心静脉导管相关血栓形成中的作用

目的观察上肢加压治疗在预防无运动能力患者经外周静脉穿刺的中心静脉导管(PICC)相关血栓形成中的作用。方法选取2020年1月至2022年8月在西安交通大学第二附属医院行上肢PICC置管术并进行导管维护的无运动能力患者84例,采用随机数字表法将其分为对照组和加压组,各42例。对照组采用被动活动干预,加压组使用空气压力波加压干预。应用彩色多普勒超声监测两组干预前和干预30 min后腋静脉和锁骨下静脉血流速度;于置管前、置管2周后,检测两组纤维蛋白原、凝血酶原时间、D-二聚体。记录两组PICC相关血栓发生情况。结果干预30 min后,两组腋静脉和锁骨下静脉血流速度均快于干预前,且加压组快于对照组,差异有统计学意义(P<0.05)。置管2周后,对照组纤维蛋白原、凝血酶原时间、D-二聚体水平高于本组置管前,且高于加压组,差异有统计学意义(P<0.05)。加压组置管前、置管2周后纤维蛋白原、凝血酶原时间、D-二聚体比较,差异无统计学意义(P>0.05)。在2周的观察期内,加压组PICC相关血栓发生率低于对照组,差异有统计学意义(P<0.05)。结论空气压力波治疗仪通过增加置管侧静脉血流速度,能有效预防无运动能力患者上肢PICC相关血栓形成。

理解相对时空观的一个简单例子

绝对时空观正确则伽利略速度变换公式成立.本文从世界观角度分析一个常见的伽利略速度变换不成立的例子,指出其中世界观的冲突,引导重建自洽的包含相对时空观的世界观.

西昌市场地剪切波速与土层深度经验关系

收集了西昌市已有的土层钻孔资料及有关报告,在此基础上踏勘布置了具有一定代表性的钻孔,逐个进行了剪切波速度的测定。对所有的剪切波速资料进行了整理,通过回归分析方法给出西昌市场地不同土类剪切波速与土层深度的关系式,为西昌市防震减灾规划土层地震反应分析提供土层的背景资料和分析依据,同时,也为西昌市以后的地震危险性、建筑工程场地分类以及抗震设防小区划提供有意义的参考资料。