Vogel-tammann-fulcher
Vogel-tammann-fulcher - Related Videos
05:56
Phase-Resolved Functional Lung MRI for Pulmonary Ventilation and Perfusion (V/Q) Assessment
0 Views •
Cited by 8 •
2024
Here, we describe the implementation of phase-resolved functional lung MRI as a contrast-agent-free proton MR technique for the assessment of pulmonary ventilation and perfusion dynamics. Validated and applicable across different field strengths and age groups, it could enhance clinical decision-making in the future by aiding in disease quantification and therapy monitoring.
08:39
Live-cell Imaging of Fungal Cells to Investigate Modes of Entry and Subcellular Localization of Antifungal Plant Defensins
0 Views •
Cited by 6 •
2017
Plant defensins play an important role in plant defense against pathogens. For effective use of these antifungal peptides as antifungal agents, understanding their modes of action (MOA) is critical. Here, a live-cell imaging method is described to study critical aspects of the MOA of these peptides.
10:44
Three-Dimensional Phase Resolved Functional Lung Magnetic Resonance Imaging
0 Views •
Cited by 4 •
2024
Three-dimensional (3D) phase-resolved functional lung (PREFUL) is a functional magnetic resonance imaging (MRI) technique that allows for quantification of regional ventilation of the whole human lung volume, using tidal breathing and contrast-agent free acquisition for 8 min. Here, we present an MR protocol to collect and analyze 3D PREFUL imaging data.
07:10
Quantification of Global Histone Post Translational Modifications Using Intranuclear Flow Cytometry in Isolated Mouse Brain Microglia
0 Views •
2023
This work describes a protocol for the quantification of global histone modifications using intranuclear flow cytometry in isolated brain microglia. The work also contains the microglia isolation protocol that was used for data collection.
08:42
Determination of Zeta Potential via Nanoparticle Translocation Velocities through a Tunable Nanopore: Using DNA-modified Particles as an Example
0 Views •
Cited by 7 •
2016
Here we use a polyurethane tunable nanopore integrated into a resistive pulse sensing technique to characterize nanoparticles surface chemistry via the measurement of particle translocation velocities, which can be used to determine the zeta potential of individual nanoparticles.
FAQs
The VTF relation uses a reciprocal temperature term, 1/(T − T₀), rather than a simple dependence on 1/T. As temperature approaches the extrapolated reference temperature T₀, this term changes rapidly, representing increasingly strong slowing of molecular motion. This behavior makes the model suitable for glass-forming materials whose transport properties depart markedly from Arrhenius behavior.
T₀ serves as an extrapolated reference temperature in the VTF expression, not simply as the ordinary glass-transition temperature. Its presence controls how sharply viscosity or relaxation time changes as temperature decreases. In engineering analysis, the fitted value helps represent the low-temperature trend and supports interpretation of behavior near the glass-transition region.
The same temperature-dependent framework can represent relaxation time and diffusion in addition to viscosity. These properties reflect different aspects of molecular mobility, so applying the relation helps engineers examine how a material’s movement, structural relaxation, or flow resistance changes together across temperature. This broader use is valuable for characterizing polymers, glasses, and other amorphous materials.
Predictions become especially sensitive as the material approaches the glass-transition region because small temperature changes can correspond to large changes in the reciprocal term involving T₀. Consequently, viscosity and relaxation estimates may shift rapidly over a narrow processing range. Engineers can use this sensitivity to identify where material handling or forming conditions may change substantially.
A typical workflow begins by measuring a temperature-dependent property, such as viscosity or relaxation behavior, for the material of interest. Engineers then represent the measurements with the VTF form and determine parameters, including the reference temperature T₀, that describe the observed trend. The fitted relation can subsequently estimate behavior at other temperatures within the relevant range.
VTF-based estimates show how viscosity or relaxation behavior changes across candidate processing temperatures. Engineers can use those trends to locate a practical range in which an amorphous material has suitable flow or molecular mobility, while recognizing that behavior may change quickly near the glass-transition region. This supports process planning for polymers, glasses, and related materials.
A VTF analysis provides a temperature-dependent description of transport and relaxation behavior that can be compared across amorphous materials. The resulting trends help connect molecular-motion changes with engineering requirements such as processing behavior and thermal operating conditions. For polymers, glasses, and other glass-forming systems, this information supports selection and design decisions near the glass-transition region.
Amorphous materials often require engineering decisions based on how rapidly their flow, diffusion, or relaxation properties change with temperature. The VTF relation supplies a model for that strongly non-Arrhenius behavior, allowing these responses to be characterized in a common framework. Its use therefore connects material characterization with manufacturing analysis and design near glass-transition conditions.