Materials Technology: Properties, Structures & Testing
1. Introduction
When choosing a material for design, manufacturing, or construction, the primary concern is matching its characteristics to the working conditions of the intended application. We must understand the properties (physical, chemical, technological, or mechanical) of the material, how to identify them, and any limitations or advantages they impose. The advancements in recent years demand materials that can withstand harsh service conditions. This necessitates careful and frequent monitoring
Read MoreElectromagnetism, Light, and Optics: A Comprehensive Overview
Huygens’ Principle
This principle describes a mechanism for constructing wavefronts. A wavefront is a surface passing through points where a wave oscillates with the same phase. Huygens’ principle states:
- Points on a wavefront act as sources of secondary waves.
- The envelope of these secondary waves forms a new primary wavefront.
To apply this principle, small circles (representing secondary waves) are drawn centered at points on the initial wavefront. The new wavefront is the envelope of these circles.
Read MoreLight Propagation, Reflection, and Refraction: A Comprehensive Guide
Propagation of Light
Light emitted from sources travels through various media. Substances are classified as opaque, transparent, or translucent based on their interaction with light. Opaque substances block light, while transparent substances, like water, glass, and air, allow light to pass through in a single direction. Translucent substances, such as vellum or frosted glass, scatter light, preventing clear image formation.
Light in Homogenous Media
In a homogenous, transparent medium, light travels
Read MoreUnderstanding Central Forces and Gravity
Central Forces and Angular Momentum
A central force acts along the position vector of the point where the force is applied. Gravity is a central force. Consider a particle of mass M (reference source) and a particle of mass m moving relative to M under the influence of gravity.
Angular Momentum
Angular momentum is the vector product of the position vector and linear momentum (mass times velocity).
Conservation of Angular Momentum
If the net torque is zero, angular momentum remains constant. Thus, the
Read MoreGreenhouse Climate Control: Light, Temperature, and Humidity Management
Control of Light
Using shaders, mesh, and covers, artificial light contributes to influencing plant growth.
Mesh Shading
- Polypropylene woven raffia: Available in different colors, especially white and black.
- Transparent polyester: High opacity to longwave radiation, preventing heat loss at night during the cold season. Used to retain heat accumulated during the day. Also used to protect from excessive solar radiation.
Whiteners (Covers)
Used to reduce solar radiation and luminosity during periods of excessive
Read MoreGothic Cathedrals: Notre Dame, Chartres, Amiens, Reims & Sainte-Chapelle
Notre Dame Cathedral
Notre Dame is a magnificent Latin cross structure, featuring five naves and a double ambulatory. The platform’s beauty and the dome are striking. Note the graceful arches and slender columns of the platform, serving both structural and decorative purposes. Sexpartite vaults divide the deck into triangular segments. The exterior of Notre Dame is notable for its transept doors with large rose windows. The interplay of flying buttresses, pinnacles, and Gothic windows is also remarkable.
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