Children: Thermodynamics
A Temperature–Entropy (T-s) diagram is a graphical representation used in thermodynamics to illustrate the relationship between temperature (T) and entropy (s) of a system. It is particularly useful for analyzing thermodynamic processes and cycles, especially for various fluids, such as steam in power plants and refrigerants in refrigeration systems.
Thermal contact refers to the interaction at the interface between two materials that are in thermal contact with each other. This contact affects the transfer of heat between the materials. When two surfaces are brought together, they do not have perfect contact due to microscopic irregularities, leading to gaps and variations in contact area. These irregularities influence thermal conductivity and the overall thermal resistance at the interface.
Thermal contact conductance refers to the measure of the efficiency of heat transfer across an interface between two materials in contact. When two surfaces are in contact, they do not have perfect thermal connections due to surface roughness, material properties, and the presence of contaminants or insulating layers, which can impede the flow of heat. The thermal contact conductance (often denoted as \( h_c \)) quantifies how effectively heat can be conducted through this interface.
A thermal copper pillar bump is a type of microelectronic interconnect technology used to improve heat dissipation and electrical performance in semiconductor devices, particularly in 3D packaging and flip-chip applications. Here are some key points about thermal copper pillar bumps: 1. **Structure**: A copper pillar bump typically consists of a small vertical column (the pillar) made of copper. It can be formed directly on the chip's surface or on a substrate.
Thermal decomposition is a chemical process in which a compound breaks down into simpler substances or elements when subjected to heat. This reaction typically involves the breaking of chemical bonds within the molecule, leading to the formation of two or more products. Thermal decomposition can occur in various substances, including organic and inorganic compounds. Some common characteristics of thermal decomposition include: 1. **Temperature Dependency**: The rate of decomposition and the exact temperature at which it occurs vary depending on the specific compound and its stability.
A thermal diode is a device that allows heat to flow in one direction more easily than in the opposite direction, analogous to how an electrical diode allows current to flow in one direction while blocking it in the other. Thermal diodes are used in various applications where temperature differences need to be managed. Here are some key points regarding thermal diodes: 1. **Functionality**: Thermal diodes exploit materials with varying thermal conductivities or thermal properties.
Thermal equilibrium refers to a condition in which two or more objects or systems exchanged heat until they reach the same temperature, resulting in no net flow of thermal energy between them. At thermal equilibrium, the temperature of the objects remains constant over time because the energy they exchange is balanced.
Thermal expansion refers to the tendency of matter to change its shape, area, and volume in response to changes in temperature. As the temperature of a substance increases, its particles move more rapidly, leading to an increase in the average distance between them. This results in the expansion of the material. Thermal expansion occurs in all states of matter—solids, liquids, and gases—but the degree of expansion can vary significantly among different materials.
Thermal hydraulics is a branch of engineering that deals with the study of heat transfer and fluid flow, particularly in systems involving liquids and gases. It combines principles from thermodynamics, fluid mechanics, heat transfer, and sometimes chemical processes to analyze and design systems where the interaction between heat and fluid motion is crucial.
Thermal inductance is a concept used in the study of heat transfer in materials and systems, drawing an analogy to electrical inductance in circuits. While electrical inductance pertains to the ability of a component to resist changes in current, thermal inductance measures the ability of a material or system to resist changes in temperature in response to heat flow. In more technical terms, thermal inductance describes how changes in temperature over time relate to heat flow through a medium.
Thermal mass refers to the ability of a material to absorb, store, and release heat. This property is particularly important in the context of building design and architecture, where materials with high thermal mass can help regulate indoor temperatures, improve energy efficiency, and enhance comfort. Materials with high thermal mass, such as concrete, brick, and stone, can absorb heat during the day when temperatures are higher and release it during the night when temperatures drop.
A thermal oscillator is a type of system or device that generates oscillations or vibrations as a result of thermal effects, primarily due to temperature fluctuations and thermal processes. It typically involves the interplay between thermal energy and the mechanical properties of materials. In essence, thermal oscillators can be thought of in terms of how they exploit the relationship between heat and mechanical motion.
Thermal physics is a branch of physics that deals with the concepts of heat and temperature and their relation to energy and work. It encompasses the principles of thermodynamics, statistical mechanics, and kinetic theory, and provides a comprehensive understanding of how thermal energy affects physical systems. Key areas within thermal physics include: 1. **Thermodynamics**: This is the study of the relationships between heat, work, temperature, and energy.
Thermal pressure refers to the pressure exerted by a gas or fluid due to its temperature. It is a manifestation of the kinetic energy of the particles in the substance. As the temperature increases, the molecules move more rapidly, leading to more collisions with the walls of a container and, consequently, an increase in pressure.
A thermal reservoir is a system, typically part of a thermodynamic cycle, that can absorb and release heat without experiencing a significant change in temperature. It acts as a source or sink for thermal energy and is usually conceptualized in discussions of heat engines, refrigerators, and other thermal systems. In essence, thermal reservoirs can be divided into two main categories: 1. **Hot Reservoir**: This is a source of heat at a higher temperature.
Thermal transmittance, often represented by the symbol \( U \), is a measure of how well a building element (such as walls, roofs, windows, or doors) can conduct heat. It quantifies the rate of heat transfer through a unit area of the building element for a temperature difference of one degree (typically measured in watts per square meter per degree Kelvin, W/m²·K or W/m²·°C).
Thermalisation is the process by which a system approaches thermal equilibrium, meaning that the temperature becomes uniform throughout the system and the distribution of energy among the particles becomes constant. In other words, it refers to the way in which energy is redistributed in a system until it reaches a state where all parts of the system have the same temperature and energy distribution, aligning with the principles of thermodynamics.
The thermo-dielectric effect refers to the phenomenon in which the dielectric properties of a material change in response to temperature variations. In simpler terms, dielectric materials, which are insulators that can be polarized by an electric field, can exhibit changes in their ability to store electrical energy (capacitance) or resist electrical conduction based on temperature alterations.
Thermodynamic diagrams are graphical representations used in thermodynamics to illustrate relationships between different thermodynamic properties of substances, such as temperature, pressure, volume, and enthalpy. These diagrams are essential tools for understanding and analyzing thermodynamic cycles, phase changes, and the behavior of different materials under various conditions. Some common types of thermodynamic diagrams include: 1. **Pressure-Temperature (P-T) Diagram**: Shows the relationship between pressure and temperature for a substance.
Thermodynamic instruments are devices used to measure and analyze various thermodynamic properties of substances, such as temperature, pressure, volume, and energy. These instruments help scientists and engineers understand and apply the principles of thermodynamics in various applications, ranging from industrial processes to environmental studies. Here are some common types of thermodynamic instruments: 1. **Thermometers**: Measure temperature. There are several types, including mercury, digital, and resistance thermometers.