Trialism
Trialism generally refers to the theoretical framework or political arrangement that divides power among three distinct entities, groups, or administrative units, rather than the more commonly known dualism (which involves two entities). The term can be applied in various contexts, including political science, sociology, and even philosophy. In a political context, trialism might describe arrangements where power is shared among three different regions, ethnic groups, or governing bodies within a state.
Antoine equation
The Antoine equation is a mathematical expression used to relate the vapor pressure of a pure substance to its temperature. It provides a way to estimate the vapor pressure of a liquid at various temperatures, which is particularly useful in fields such as chemistry, chemical engineering, and thermodynamics.
Pitzer equations
The Pitzer equations, developed by K. S. Pitzer in the 1970s, are used to describe the thermodynamic properties of electrolyte solutions. They provide a way to calculate activity coefficients of ions in solution, which are essential for understanding how ions behave in various concentrations, particularly in solutions with high ionic strength. The Pitzer equations account for interactions between different ions and the resulting deviations from ideal behavior in the solutions.
Bromley equation
The Bromley equation is a mathematical formulation used in the field of geophysics, particularly in studies related to subsurface geology and hydrocarbon reservoirs. It is primarily utilized to estimate the porosity of a rock based on its density and sonic velocity measurements. However, it is essential to note that there might be different contexts for the term "Bromley equation," as it can refer to various equations or models depending on the specific scientific discipline.
Duhem–Margules equation
The Duhem-Margules equation is a thermodynamic relationship that describes the behavior of a binary solution in terms of its components’ chemical potentials and mole fractions. It is particularly important in physical chemistry and chemical engineering for understanding phase equilibria in mixtures.
Eötvös rule
Eötvös rule, named after Hungarian physicist Loránd Eötvös, is an empirical rule in geophysics that describes the relationship between the density of a fluid and the gravitational force acting on it. Specifically, it states that the gravitational attraction of a fluid is proportional to its density when considering the gravitational potential difference over a vertical column of that fluid.
Gibbs–Duhem equation
The Gibbs–Duhem equation is a relationship in thermodynamics that describes the changes in the chemical potential of a system in relation to its temperature, pressure, and composition. It arises from the fundamental thermodynamic definition of the differential change in the Gibbs free energy \( G \).
Gibbs–Thomson equation
The Gibbs–Thomson equation describes the relationship between the curvature of a phase boundary and the thermodynamic properties of that phase. It is particularly important in the fields of materials science, thermodynamics, and physical chemistry, as it relates to the stability of small particles, droplets, and other interfaces.
Maxwell relations
Maxwell's relations are a set of equations in thermodynamics that arise from the equality of mixed second derivatives of thermodynamic potentials. They provide a connection between different thermodynamic properties and facilitate calculations involving changes in state variables. Maxwell's relations are derived from the fundamental thermodynamic potentials: the internal energy \( U \), the Helmholtz free energy \( F \), the Gibbs free energy \( G \), and the enthalpy \( H \).
A table of thermodynamic equations provides a collection of key equations and relationships used in thermodynamics, which is the study of the relationships between heat, work, temperature, and energy. These equations are fundamental for understanding various thermodynamic processes and systems. Below is a summary of some important thermodynamic equations organized by categories: ### 1.
Isochoric process
An isochoric process is a thermodynamic process in which the volume of the system remains constant. Since the volume does not change, the work done by or on the system during this process is zero. This is in contrast to isothermal (constant temperature), adiabatic (no heat exchange), and isobaric (constant pressure) processes.
Terrace ledge kink model
The term "terrace ledge kink model" pertains to a concept in the field of materials science, particularly in the study of crystal growth and surface morphology. This model is used to describe the dynamics of crystal surfaces during growth processes, where the arrangement of atoms or molecules leads to the formation of specific surface features. Here's a brief overview of the key components: 1. **Terraces**: These are flat regions on the crystal surface where atoms are arranged in an orderly, two-dimensional array.
UNIFAC Consortium
The UNIFAC Consortium is a collaborative organization focused on the development and maintenance of the UNIFAC (Universal Functional Activity) model, which is a method used for predicting thermodynamic properties of mixtures, particularly in the fields of chemical engineering and process design. The UNIFAC model is based on group contribution methods, which means it estimates interactions between molecular groups in a mixture to provide information about phase equilibria and other thermodynamic properties.
Nuclear fission
Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into two or more smaller nuclei, along with the release of a significant amount of energy. This process typically occurs in heavy elements such as uranium-235 or plutonium-239. The fission process can be initiated by the absorption of a neutron by the nucleus of the fissile atom. When the nucleus absorbs the neutron, it becomes unstable and splits into two smaller nuclei, known as fission fragments.
Nuclear fusion
Nuclear fusion is a process in which two light atomic nuclei combine to form a heavier nucleus, releasing a significant amount of energy in the process. This is the same reaction that powers the sun and other stars. In fusion, the strong nuclear force overcomes the electrostatic repulsion between the positively charged protons when the nuclei are brought close enough together, allowing them to merge.
Thermodynamic cycles
Thermodynamic cycles are a series of processes that involve the transfer of heat and work in thermodynamic systems, returning to their initial state by the end of the cycle. These cycles are fundamental to the operation of many heat engines, refrigerators, and heat pumps, as they illustrate how energy is converted from one form to another while adhering to the laws of thermodynamics. ### Basic Concepts: 1. **System**: A specified quantity of matter or region in space that is under study.
Endothermic process
An endothermic process is a type of chemical reaction or physical change that absorbs heat energy from its surroundings. This means that during the process, the system takes in thermal energy, leading to a decrease in the temperature of the surrounding environment. Endothermic processes can occur in various contexts, including: 1. **Chemical Reactions**: Many chemical reactions require energy input to break chemical bonds.
In thermodynamics, conjugate variables are pairs of physical quantities that are related to each other in a specific way, typically in the context of work and energy interactions in a thermodynamic system. Conjugate variables often arise in the context of the first and second laws of thermodynamics and are fundamental to understanding the relationships between different forms of energy and the processes that occur in thermodynamic systems.
Cryoscopic constant
The cryoscopic constant, often denoted as \( K_f \), is a property of a solvent that describes how much the freezing point of the solvent decreases when a solute is dissolved in it. It's specifically used in the context of colligative properties, which are properties that depend on the number of solute particles in a given amount of solvent rather than the identity of the solute.
Energy value of coal
The energy value of coal can vary significantly depending on its grade and type. Coal is classified into several categories, including anthracite, bituminous, sub-bituminous, and lignite, with each having different energy content. 1. **Anthracite:** This type of coal has the highest carbon content (around 86–97%) and energy value, typically ranging from about 24 to 30 million British thermal units (BTUs) per ton.