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Updated: Jul 7, 2026
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Biaxial Mechanical Characterizations of Atrioventricular Heart Valves
Published on: April 9, 2019
Design of a cemented, radial gradient-index triplet
Applied Optics
|February 15, 2008
Abstract:
We show the possibility of simultaneously eliminating all third-and fifth-order monochromatic aberrations by using an objectiveconsisting of three cemented lenses with radial distribution ofrefractive indices. We present design procedures for removal ofthese aberrations and reduction of residual higher-orderaberrations.
Related Concept Videos
01:24Design Example: Aggregate Gradation
The right type and quality of aggregates are crucial for concrete as they significantly influence its properties, mix proportions, and cost-effectiveness. If different sources are available for sand, the commonly used fine aggregate in concrete, the selection of sand is primarily based on its gradation.
The grading, or particle-size distribution, of sand is determined using sieve analysis, with standard sizes ranging from 150 μm to 10 mm (ASTM No. 100 sieve to 3⁄8 in. sieve). Sand is sampled...
The grading, or particle-size distribution, of sand is determined using sieve analysis, with standard sizes ranging from 150 μm to 10 mm (ASTM No. 100 sieve to 3⁄8 in. sieve). Sand is sampled...
01:27Gradient Fields
A gradient field is a vector field derived from a scalar field. A scalar field assigns a single numerical value to every point in space, such as temperature, pressure, or electric potential. The gradient field describes how that value changes from point to point. It gives both the direction of the fastest increase and the rate of change in that direction.For a scalar field f(x, y), the gradient is written as\begin{equation*}\nabla f=\left\langle \jfrac{\partial f}{\partial x},\jfrac{\partial...
01:28Triple Integrals in Cylindrical Coordinates
Cylindrical coordinates describe a point in three-dimensional space using three values: radial distance, angle, and height. The height gives the position above the xy-plane, the radial distance measures how far the point is from the z-axis, and the angle describes the point’s direction from the positive x-axis in the xy-plane. This system is especially useful for regions with circular symmetry because it matches the natural geometry of cylinders, disks, and circular tanks.To calculate volume,...
01:21Aggregate Cement Ratio
The Aggregate Cement ratio refers to the weight of aggregate divided by the weight of cement in a concrete mix. Altering this ratio has profound effects on the concrete's properties. This ratio plays a pivotal role in determining the strength, workability, and durability of concrete. When the Aggregate Cement ratio is higher, the mix is leaner, meaning it has less cement paste to lubricate the aggregate, potentially making the concrete less workable. Such mixes, known as lean, enhance the...
01:22Types of Cement II
Portland blast-furnace cement is made by blending Portland cement clinker with granulated blast-furnace slag, which accounts for 25 to 65 percent of the cement's weight. Despite its similarities to ordinary Portland (Type I) cement in terms of fineness and setting times, its early strength is lower, though it achieves comparable strength later on. It's particularly suited for mass concrete structures and marine environments due to its lower heat of hydration and superior sulfate resistance.
01:22Design Example: Distributing Reinforcements in Concrete Sections
The topic explores the practical aspects of adjusting steel reinforcements within a concrete beam section to meet specific design requirements. When designing a reinforced concrete beam, it is essential to distribute the steel reinforcements properly to ensure structural integrity and efficiency. The example provided details a scenario where a beam requires a total steel cross-section of 4 square inches. The engineer identifies that the available steel bars have a nominal diameter of 1.693...