Steel Microstructures: Transformations, Heat Treatments, and Surface Hardening
Steel Microstructures and Transformations
Pearlite: Eutectoid decomposition of austenite into alternating layers of ferrite and cementite. The cooling rate determines the fineness of the pearlite (fine or coarse). Bainite: A mixture of ferrite needles with cementite precipitation at the edges. High cooling rates favor bainite over pearlite. Austenite transforms from FCC to BCC. Shear deformation within the austenite leads to the dissemination and precipitation of supersaturated ferrite. Bainite exhibits
Read MoreMarriage: History, Requirements, and Legal Aspects
Marriage
Marriage is the primary social institution established to create a family. It is recognized and legitimized by society. The primary relationship is governed by interpersonal relations, whether between people of the same or different sexes, and can be religious, civil, or both. It involves a sexual relationship protected and supported by the legal system.
Throughout history, marriage has shown variability, including plural or monogamous forms, and relationships between people of the same or
Read MoreAristotle’s Metaphysics: Substance, Form, and Nature
Substance
Substance refers to an independent entity, that which predicates the attributes. From the Latin substantia, a translation of the Greek ousia. Etymologically, “that which stands below.” It has a complex meaning, designating:
- That which underlies the properties: for example, Socrates, to whom we predicate the traits of being Athenian, being a student of Plato, etc.
- That which remains through accidental change: Socrates remains the same individual, although his appearance may change over time.
Empiricism: Core Principles and Impact on Philosophy
In a broad sense, empiricism describes any philosophical position that considers experience as the source of knowledge or the limit of knowledge (maintained by numerous philosophers, such as Aristotle, Epicurus, the Stoics, Thomas Aquinas, and Ockham). However, in a strict sense, empiricism is a philosophical current that emerged in opposition to rationalism in 17th-century England, developing during the 18th century. Its main representatives are J. Locke, G. Berkeley, and D. Hume. T. Hobbes is
Read MoreRaw Materials and Energy Sources in Spain: An In-Depth Look
Raw Materials and Energy Sources
Raw materials are resources used to make products, either finished or semi-finished. They can be classified into two types:
- Raw materials of organic origin
- Mineral raw materials
Mineral Raw Materials
a) Metallic Minerals: Found in certain areas.
b) Non-metallic Minerals: Found in Paleozoic formations.
Industrial rocks (clay, sand, limestone, etc.) are also important. National production of minerals is insufficient for self-sufficiency, requiring trade, which creates a deficit.
Read MorePulmonary and Plant Respiration: A Detailed Analysis
Pulmonary Respiration
In pulmonary respiration, gas exchange takes place in specialized cavities with highly vascularized, thin walls called lungs. These cavities are connected to the outside through:
- Nostrils: Where air is heated and cleaned of impurities.
- Pharynx: Connects the nasal passages, mouth, and throat.
- Larynx: Reinforced by cartilage and contains the vocal cords.
- Trachea: A tube reinforced with cartilaginous rings, serving as a cleaning area, which bifurcates into the bronchi.
- Bronchi, Bronchioles,