Joule Per Kelvin
Joule Per Kelvin - Related Videos
01:23
The Joule and Joule–Thomson Experiments
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2026
Consider an adiabatic system composed of two chambers, A and B, designed such that no heat flows into or out of the system. Initially, chamber A is filled with a gas at a fixed temperature T1, pressure p1, and volume V1, while chamber B is evacuated. The gas is then gradually forced through a rigid, porous barrier to chamber B, ultimately reaching temperature T2, pressure p2, and volume V2. A piston on the right side maintains a constant pressure (p2), which is lower than p1. The significant...
01:21
Joule-Thomson Effect
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2025
The Joule-Thomson effect, also known as the Joule-Kelvin effect, describes the temperature change of a fluid when it is forced through a valve or porous plug while keeping it in a thermally insulated environment. This experiment is called a throttling process. This is an important effect widely used in refrigeration and the liquefaction of gases. This experiment forces high-pressure gas through a throttle valve or a porous plug to a lower-pressure region. The gas expands as it passes through to...
01:22
Gas Thermometers and the Kelvin Scale
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2023
The definition of temperature in terms of molecular motion suggests that there should be a lowest possible temperature, where the average kinetic energy of molecules is zero (or the minimum allowed by quantum mechanics). Experiments confirm the existence of such a temperature, called absolute zero. An absolute temperature scale is one whose zero point is absolute zero. Such scales are convenient in science because several physical quantities, such as the volume of an ideal gas, are directly...
10:49
Surface Potential Measurement of Bacteria Using Kelvin Probe Force Microscopy
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Cited by 17 •
2014
Here, we present a protocol explaining the use of Kelvin probe force microscopy as a tool for generating high resolution nano-scale surface potential maps. This tool was applied to assess the role of surface potential on the binding capacity of microorganisms to substrate surfaces.
12:18
Co-localizing Kelvin Probe Force Microscopy with Other Microscopies and Spectroscopies: Selected Applications in Corrosion Characterization of Alloys
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Cited by 3 •
2022
Kelvin probe force microscopy (KPFM) measures surface topography and differences in surface potential, while scanning electron microscopy (SEM) and associated spectroscopies can elucidate surface morphology, composition, crystallinity, and crystallographic orientation. Accordingly, the co-localization of SEM with KPFM can provide insight into the effects of nanoscale composition and surface structure on corrosion.
FAQs
A J/K value does not identify a single thermodynamic quantity by itself. In heat-capacity work, it characterizes the energy-temperature response of a system; in entropy calculations, it characterizes a change obtained from reversible heat divided by absolute temperature. Recognizing the context is essential when interpreting measurements or equations that share the same unit.
Absolute temperature is essential when J/K appears in the entropy relation because reversible heat transfer is divided by T. Using the temperature specified in that relation preserves the intended quantitative connection between transferred energy and entropy change. This makes temperature conditions central when comparing entropy-related results across different thermal systems.
The unit provides a common quantitative bridge between measured thermal behavior and microscopic statistical behavior. At the macroscopic level, physicists can record relationships between energy and temperature; at the microscopic level, the same thermodynamic quantities support statistical descriptions. This shared energy-temperature basis allows both perspectives to be connected in physics.
In calorimetry, determine the energy transferred to or from a system and track the associated temperature change. Expressing their relationship in J/K allows the thermal response to be reported consistently. The resulting quantity can then support heat-capacity analysis and quantitative comparisons among materials studied under thermal conditions.
During material studies, J/K provides the unit framework for reporting thermal quantities used in specific-heat measurements. Researchers can use those measurements for quantitative comparisons of materials, connecting an observed energy-temperature response to differences among samples. This approach turns thermal testing into a consistent basis for comparing material behavior.
In analyses of engines and refrigerators, J/K quantities help connect heat transfer and temperature to thermal-system behavior. Heat-capacity values characterize thermal responses, while entropy changes use reversible heat and absolute temperature. Applying the appropriate interpretation allows researchers to examine these systems quantitatively rather than treating every J/K value as the same physical quantity.