scholarly journals Monitoring and Data Analysis in Small-Scale Landslide Physical Model

2021 ◽  
Vol 11 (11) ◽  
pp. 5040
Author(s):  
Sara Pajalić ◽  
Josip Peranić ◽  
Sandra Maksimović ◽  
Nina Čeh ◽  
Vedran Jagodnik ◽  
...  
Keyword(s):  
Physical Modeling ◽  
High Speed ◽  
Laser Scanning ◽  
Surface Displacement ◽  
Physical Models ◽  
Small Scale ◽  
Advantages And Disadvantages ◽  
Artificial Rainfall ◽  
Landslide Development ◽  
Fast Flow

Physical modeling of landslides using scaled landslide models began in the 1970s in Japan at scaled natural slope physical models. Laboratory experiments of landslide behavior in scaled physical models (also known as flume or flume test) started in the 1980s and 1990s in Canada, Japan, and Australia under 1 g conditions. The main purpose of the landslide physical modeling in the last 25 years was research of initiation, motion, and accumulation of fast flow-like landslides caused by infiltration of water in a slope. In October 2018, at the Faculty of Civil Engineering University of Rijeka, started a four-year research project “Physical modeling of landslide remediation constructions’ behavior under static and seismic actions” funded by the Croatian Science Foundation. This paper presents an overview of the methods and monitoring equipment used in the physical models of a sandy slope exposed to artificial rainfall. Landslide development was monitored by observation of volumetric water content and acceleration as well as by observations of surface displacement by means of high-speed stereo cameras, terrestrial laser scanning, and structure-from-motion photogrammetry. Some of the preliminary results of the initial series of experiments are presented, and advantages and disadvantages of the used equipment are discussed.

Influence of the Lateral Ventricles and Irregular Skull Base on Brain Kinematics due to Sagittal Plane Head Rotation

2002 ◽  
Vol 124 (4) ◽  
pp. 422-431 ◽  
Author(s):  
J. Ivarsson ◽  
D. C. Viano ◽  
P. Lo¨vsund
Keyword(s):  
Skull Base ◽  
High Speed ◽  
Sagittal Plane ◽  
Liquid Paraffin ◽  
Angular Acceleration ◽  
Surface Displacement ◽  
Human Head ◽  
Physical Models ◽  
Peak Strain ◽  
Lateral Ventricles

Two-dimensional physical models of the human head were used to investigate how the lateral ventricles and irregular skull base influence kinematics in the medial brain during sagittal angular head dynamics. Silicone gel simulated the brain and was separated from the surrounding skull vessel by paraffin that provided a slip interface between the gel and vessel. A humanlike skull base model (HSB) included a surrogate skull base mimicking the irregular geometry of the human. An HSBV model added an elliptical inclusion filled with liquid paraffin simulating the lateral ventricles to the HSB model. A simplified skull base model (SSBV) included ventricle substitute but approximated the anterior and middle cranial fossae by a flat and slightly angled surface. The models were exposed to 7600 rad/s2 peak angular acceleration with 6 ms pulse duration and 5 deg forced rotation. After 90 deg free rotation, the models were decelerated during 30 ms. Rigid body displacement, shear strain and principal strains were determined from high-speed video recorded trajectories of grid markers in the surrogate brains. Peak values of inferior brain surface displacement and strains were up to 10.9X (times) and 3.3X higher in SSBV than in HSBV. Peak strain was up to 2.7X higher in HSB than in HSBV. The results indicate that the irregular skull base protects nerves and vessels passing through the cranial floor by reducing brain displacement and that the intraventricular cerebrospinal fluid relieves strain in regions inferior and superior to the ventricles. The ventricles and irregular skull base are necessary in modeling head impact and understanding brain injury mechanisms.

scholarly journals Application of additive technology for the study of resonance oscillations in structures

2018 ◽  
Vol 251 ◽  
pp. 04001 ◽  
Author(s):  
Konstantin Makarov ◽  
Evgeny Yurchenko ◽  
Elena Yurchenko
Keyword(s):  
Physical Modeling ◽  
Physical Models ◽  
Small Scale ◽  
Additive Technology ◽  
Harmonic Oscillations ◽  
Resonance Frequencies ◽  
Scale Models ◽  
Concrete Building ◽  
Resonance Oscillations

The methodic of studying the vibrations of small-sized physical models using additive technology has been developed. The results of the experimental determination of the resonance frequencies for harmonic oscillations and the calculation of the phase shift for two small-scale models of a three-story reinforced concrete building with a nonrigel frame has been presented. It has been shown that the production of models on a 3-D printer makes it possible to reduce the laboriousness of their manufacture, and also to expand the possibilities for accounting of operational defects in buildings and structures derived from seismic, vibrational and other types of vibrational influences based on physical modeling.

Small-scale physical modeling of seismic-wave propagation using unconsolidated granular media

Geophysics ◽  
2014 ◽  
Vol 79 (6) ◽  
pp. T323-T339 ◽  
Author(s):  
Ludovic Bodet ◽  
Amine Dhemaied ◽  
Roland Martin ◽  
Régis Mourgues ◽  
Fayçal Rejiba ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Seismic Wave ◽  
Physical Modeling ◽  
Granular Media ◽  
Laser Doppler Vibrometer ◽  
Seismic Wave Propagation ◽  
Acoustic Mode ◽  
Physical Models ◽  
Small Scale ◽  
Near Surface

Laboratory physical modeling and laser-based experiments are frequently proposed to tackle theoretical and methodological issues related to seismic prospecting, e.g., when experimental validations of processing or inversion techniques are required. Lasers are mainly used to simulate typical field acquisition setups on homogeneous and consolidated materials assembled into laboratory-scale physical models (PMs) of various earth structures. We suggested the use of granular materials to study seismic-wave propagation in unconsolidated and porous media and target near-surface exploration and hydrogeologic applications. We designed and tested the reproducibility of an experimental procedure to build and probe PMs consisting of micrometric glass beads (GBs). A mechanical source and a laser-Doppler vibrometer were used to record small-scale seismic lines at the surface of three GBs models. When guided surface acoustic mode theory should prevail in such unconsolidated granular packed structure under gravity, we only considered elastic-wave propagation in stratified media to interpret recorded data. Thanks to basic seismic processing and inversion methods (first arrivals and dispersion analyses), we were able to correctly retrieve the gradients of pressure- and shear-wave velocities in our models. A 3D elastic finite difference simulation of the experiment offered, despite significant differences in terms of amplitudes, a supplementary validation of our approximation, as far as elastic properties of the medium were concerned.

scholarly journals Physical modeling applied in evaluation of the safety and efficiency of vessel mooring plans

RBRH ◽  
2018 ◽  
Vol 23 (0) ◽  
Author(s):  
Rafael Esferra ◽  
José Carlos de Melo Bernardino ◽  
Paolo Alfredini
Keyword(s):  
Physical Modeling ◽  
Physical Models ◽  
Scale Model ◽  
Small Scale ◽  
Mooring Lines ◽  
Safe Alternative ◽  
Adverse Conditions ◽  
Cargo Handling ◽  
Favorable Conditions

ABSTRACT For cargo handling to be carried out safely and efficiently, port terminals should provide favorable conditions of shelter, thus avoiding excessive movement of moored vessels and mitigating strengths on mooring lines. However, terminals in which the influence of waves, winds or currents provide adverse conditions to keep a vessel moored need to pay attention to the mooring arrangement of the vessels, through studies that guarantee the effectiveness of the system. In this context, small-scale hydraulic physical models are the most accurate tool for simulation of mooring lines plans of vessels, since they can accurately reproduce all the complexity of the hydrodynamics and its interaction with the vessel. This manuscript presents the technique of physical modeling in vessel mooring studies and its application in a case study made for Ponta da Madeira Port Terminal. In a scale model 1:170 was carried out a comparison of two proposed mooring arrangements for the Valemax class bulk carrier, the results of which allowed to define a safe alternative that made the berthing operation feasible during almost 100% of the time.

scholarly journals Methods for detecting channel bed surface changes in a mountain torrent – experiences from the Dorfbach torrent

2015 ◽  
Vol 70 (4) ◽  
pp. 265-279 ◽  
Author(s):  
C. Willi ◽  
C. Graf ◽  
Y. Deubelbeiss ◽  
M. Keiler
Keyword(s):  
Debris Flow ◽  
Spatial Resolution ◽  
Cross Sections ◽  
Laser Scanning ◽  
Small Scale ◽  
Sources Of Information ◽  
Field Methods ◽  
Geomorphological Mapping ◽  
Flow Monitoring ◽  
Advantages And Disadvantages

Abstract. The erosion of and depositions on channel bed surfaces are instrumental to understanding debris flow processes. We present an overview of existing field methods and highlight their respective advantages and disadvantages. Terrestrial laser scanning (TLS), airborne laser scanning (ALS), erosion sensors, cross sections (CS) and geomorphological mapping are compared. Additionally, two of these approaches (i.e. TLS and CS) are tested and applied in the channel reaches of the torrent catchments. The results of the comparison indicate that the methods are associated with variable temporal and spatial resolution as well as data quality and invested effort. TLS data were able to quantify small-scale variations of erosion and deposition volumes. While the same changes could be detected with CS and geomorphological mapping, it was only possible with lower precision and coarser spatial resolution. The study presents a range of potential methods that can be applied accordingly to address the objectives and to support the analyses of specific applications. The availability of erosion data, acquired mainly by TLS and ALS, in combination with debris-flow monitoring data, provides promising sources of information to further support torrent risk management.

Investigation of rainfall-induced failure processes and characteristics of wedge slopes using physical models

2020 ◽  
Author(s):  
Chia-Ming Lo ◽  
Chen-Han Chu ◽  
Yi-Xiang Su
Keyword(s):  
Physical Modeling ◽  
Slope Failure ◽  
Wedge Angle ◽  
Physical Models ◽  
Small Scale ◽  
Intersection Angle ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Free Falling ◽  
The Impact

<p>In this study, the small-scale physical modeling tests have considered the impact of the infiltration of rainfall in order to investigate the processes involved in wedge slope deformation and failure. We are conducted under controlled conditions of the intersection angle and half wedge angle. Observations obtained during each stage of deformation and failure were used to explain how gravity deformation varies on wedge slopes, and infer how rainfall influence slope failure. The results indicate that half wedge angle is a crucial factor in the deformation failure of slopes. The failure mechanisms of low intersection angle slopes (sliding model) differ considerably from those of high intersection angle slopes (free falling or toppling model). The infiltration of surface water can have a significant influence on rock layer deformation and the speed of failure. Details of the failure characteristics of wedge slope models are discussed in this paper.</p><p><strong>Keywords:</strong> physical modeling, rainfall, wedge slope, the intersection angle, half wedge angle.</p>

Five-Dimensional Microscopy using Widefield-Deconvolution: Practical Considerations and Biological Applications

1996 ◽  
Vol 54 ◽  
pp. 268-269
Author(s):  
W.F. Marshall ◽  
K. Oegema ◽  
J. Nunnari ◽  
A.F. Straight ◽  
D.A. Agard ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
High Speed ◽  
Laser Scanning ◽  
Ccd Camera ◽  
Image Plane ◽  
Time Lapse ◽  
Laser Scanning Confocal Microscopy ◽  
Three Dimensions ◽  
Excitation Light ◽  
Cooled Ccd

The ability to image cells in three dimensions has brought about a revolution in biological microscopy, enabling many questions to be asked which would be inaccessible without this capability. There are currently two major methods of three dimensional microscopy: laser-scanning confocal microscopy and widefield-deconvolution microscopy. The method of widefield-deconvolution uses a cooled CCD to acquire images from a standard widefield microscope, and then computationally removes out of focus blur. Using such a scheme, it is easy to acquire time-lapse 3D images of living cells without killing them, and to do so for multiple wavelengths (using computer-controlled filter wheels). Thus, it is now not only feasible, but routine, to perform five dimensional microscopy (three spatial dimensions, plus time, plus wavelength).Widefield-deconvolution has several advantages over confocal microscopy. The two main advantages are high speed of acquisition (because there is no scanning, a single optical section is acquired at a time by using a cooled CCD camera) and the use of low excitation light levels Excitation intensity can be much lower than in a confocal microscope for three reasons: 1) longer exposures can be taken since the entire 512x512 image plane is acquired in parallel, so that dwell time is not an issue, 2) the higher quantum efficiently of a CCD detect over those typically used in confocal microscopy (although this is expected to change due to advances in confocal detector technology), and 3) because no pinhole is used to reject light, a much larger fraction of the emitted light is collected. Thus we can typically acquire images with thousands of photons per pixel using a mercury lamp, instead of a laser, for illumination. The use of low excitation light is critical for living samples, and also reduces bleaching. The high speed of widefield microscopy is also essential for time-lapse 3D microscopy, since one must acquire images quickly enough to resolve interesting events.

Recent Patents on the Angular Contact Ball Bearing of High-Speed Motorized Spindle

2020 ◽  
Vol 13 ◽  
Author(s):  
Yudong Bao ◽  
Linkai Wu ◽  
Yanling Zhao ◽  
Chengyi Pan
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Rapid Development ◽  
Ceramic Materials ◽  
Development Trend ◽  
Numerical Control ◽  
Angular Contact Ball Bearing ◽  
Practical Applications ◽  
High Speed Cutting ◽  
Advantages And Disadvantages

Background:: Angular contact ball bearings are the most popular bearing type used in the high speed spindle for machining centers, The performance of the bearing directly affects the machining efficiency of the machine tool, Obtaining a higher value is the direction of its research and development. Objective:: By analyzing the research achievements and patents of electric spindle angular contact bearings, summarizing the development trend provides a reference for the development of electric spindle bearings. Methods:: Through the analysis of the relevant technology of the electric spindle angular contact ball bearing, the advantages and disadvantages of the angular contact ball bearing are introduced, and the research results are combined with the patent analysis. Results:: With the rapid development of high-speed cutting and numerical control technology and the needs of practical applications, the spindle requires higher and higher speeds for bearings. In order to meet the requirements of use, it is necessary to improve the bearing performance by optimizing the structure size and improving the lubrication conditions. Meanwhile, reasonable processing and assembly methods will also have a beneficial effect on bearing performance. Conclusion:: With the continuous deepening of bearing technology research and the use of new structures and ceramic materials has made the bearing's limit speed repeatedly reach new highs. The future development trend of high-speed bearings for electric spindles is environmental protection, intelligence, high speed, high precision and long life.

scholarly journals High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiang Lan Fan ◽  
Jose A. Rivera ◽  
Wei Sun ◽  
John Peterson ◽  
Henry Haeberle ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Fluorescence Signal ◽  
Imaging Method ◽  
Spatiotemporal Resolution ◽  
Two Photon

AbstractUnderstanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.

Sign in / Sign up

Export Citation Format

Share Document