Properties and Uses of Common Metals
Copper
It exists in pure form in nature and in minerals such as sulfides and oxides. Copper is an excellent electrical and thermal conductor. It is tough, wear-resistant, very ductile, and malleable.
Alloys:
- Bronze (copper + tin + others)
- Brass (copper + zinc + others)
- Cuproaluminum
- Alpaca (copper + nickel + zinc)
- Copper-nickel
Applications:
- Cables
- Refrigerators
- Radiators
- Tin solder joints
- Naval applications
- Agriculture (fungicides and insecticides)
- Pigments
- Brass (resistant to atmospheric and marine corrosion)
Metal Properties, Structures, and Processing Techniques
Metal Characteristics
- High thermal and electrical conductivity
- Mechanical strength
- Plasticity
- High malleability
- Recyclability
Crystalline Structures
- Crystalline: When atoms are perfectly arranged in space (metals, ceramics).
- Amorphous: Only presents a short-range order (glass, glassy polymers).
Types of Crystallization
- Body-centered cubic
- Face-centered cubic
- Hexagonal close-packed
Solid Solutions
Two solid metals are soluble in one another if, in the lattice of one of them, some of its atoms can be replaced by
Read MoreSharp Force Injuries: Characteristics, Mechanisms, and Medico-Legal Aspects
Sharp Force Injuries: An Overview
Mutilating Injuries
The instrument attacks a salient part of the body. If the weapon is very sharp, it is common to join or traction avulsion mechanisms.
Atypical Incised Wounds
1. Abrasions or Erosions
Caused when the instrument is merely tangentially touching the skin, causing an erosion or partial detachment of the epidermis.
2. Zigzag or Bridging Wounds
These are due to the characteristics of the skin or region. Skin folds in loose areas form easily.
Irregular Wounds
The
Read MoreMetals and Alloys: Properties, Uses, and Applications
Depending on their origin, we distinguish natural materials like silk or quartz, synthetic, such as concrete or glass, and auxiliaries, such as polishes, lubricants, insecticides, and others.
Ferrous Metals
Ferrous materials are those whose main component is iron, associated with other substances, both metallic and non-metallic.
Iron Minerals
- Magnetite: Dark, almost black, and an excellent iron ore, with 60-70% iron.
- Red Hematite: Compact masses of red, containing 40-60% iron.
- Siderite: Yellowing, some
Understanding Electricity Generation and Electric Fields
Methods of Generating Electricity
By Rubbing:
Rubbing a glass rod against a wool cloth causes electrons (e-) to transfer from the glass to the wool. The wool cloth becomes negatively charged, and the glass rod becomes positively charged. This is known as static electricity.
Piezoelectric Effect:
When piezoelectric materials, such as quartz, are subjected to pressure (P) between two opposite sides, electric charges appear on these surfaces. This principle is used in knock sensors. The process is reversible.
Read MoreUnderstanding Physical Quantities and Measurement Principles
Understanding Physical Quantities and Measurement
Define the term ‘physical quantities’.
Physical quantities are all those properties or qualities of matter, energy, and measurable space.
Identify which of the following are physical quantities:
Density, Volume, Length, Temperature, Area, Pressure, Time.
Note: Ira, Patriotism, Beauty, Citizenship, Feeling, and Love are not physical quantities.
What is Measurement?
Measurement is the process of comparing two magnitudes of the same nature, using one as the
Read More