Surface Refraction
Surface Refraction - Related Videos
13:59
Reflection and Refraction
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2023
Source: Derek Wilson, Asantha Cooray, PhD, Department of Physics & Astronomy, School of Physical Sciences, University of California, Irvine, CA Light travels at different speeds depending on the material through which it is propagating. When light travels from one material to another, it will either slow down or speed up. In order to conserve energy and momentum, the light must change the direction in which it propagates. This bending of light is known as refraction. Some fraction of the...
09:54
Fabrication of Refractive-index-matched Devices for Biomedical Microfluidics
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Cited by 6 •
2018
This protocol describes the fabrication of microfluidic devices from MY133-V2000 to eliminate artifacts that often arise in microchannels due to the mismatching refractive indices between microchannel structures and an aqueous solution. This protocol uses an acrylic holder to compress the encapsulated device, improving adhesion both chemically and mechanically.
05:36
Subjective Refraction Test Using a Smartphone for Vision Screening
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Cited by 1 •
2024
This paper presents the protocols and clinical validation data for using a smartphone app to subjectively measure refractive error.
01:26
Influence of Earth's Curvature and Atmospheric Refraction on Leveling
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2025
During leveling, the Earth's curvature and atmospheric refraction introduce deviations in the line of sight from a true horizontal reference. When the line of sight is leveled, it remains perpendicular to the plumb line only at a single point. Beyond this, it deviates due to the Earth’s curvature, represented by the correction C. For a sight distance D, the deviation can be derived using the relationship:This relationship shows that the deviation increases quadratically with distance. Over a...
10:21
Evanescent Field Based Photoacoustics: Optical Property Evaluation at Surfaces
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Cited by 2 •
2016
Here we present a protocol to estimate material and surface optical properties using the photoacoustic effect combined with total internal reflection. This technique evanescent field-based photoacoustics can be used to create a photoacoustic metrology system to estimate materials' thicknesses, bulk and thin film refractive indices, and explore their optical properties.
FAQs
The velocity contrast between subsurface layers controls whether a refracted arrival can be interpreted as traveling along a deeper boundary. When the lower layer is faster, the seismic pulse can propagate along that interface and return upward toward the surface. This relationship lets travel-time changes reflect both material velocity and the geometry of the layer boundary.
Critically refracted waves provide information from deeper material while measurements are made at the ground surface. After reaching a boundary with a faster layer, these waves travel along that layer before returning upward. Their arrival times therefore help distinguish changes in subsurface seismic velocity and identify the position of boundaries between engineering layers.
First arrival times show when seismic energy from a surface pulse reaches each geophone. Comparing these times across the survey line reveals how quickly energy traveled through different parts of the subsurface. Engineers use the resulting travel-time pattern to estimate seismic velocities, layer thicknesses, and bedrock depth rather than relying only on isolated observations.
A basic survey generates a seismic pulse at the ground surface and places geophones to detect the returning seismic energy. The recorded first arrival times are then organized for analysis. Engineers interpret these measurements in relation to wave travel through different layers, producing estimates of subsurface velocities, layer thicknesses, and the depth to bedrock.
Analysis of the recorded travel times can provide estimates of seismic velocity for subsurface layers, the thickness of those layers, and bedrock depth. These results convert surface measurements into a model of conditions relevant to engineering decisions. The information is especially useful when designers need subsurface characterization across an area rather than a single point.
Surface Refraction supports engineering site characterization for foundation design, construction planning, and assessment of subsurface conditions. Its surface-based measurements offer a noninvasive way to investigate an area, complementing information from widely spaced boreholes. Engineers can use the interpreted velocity and depth estimates to improve their understanding of ground conditions before or during project planning.