Random Positioning Machine
Random Positioning Machine - Related Videos
11:19
AC Synchronous Machine Characterization
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2023
Source: Ali Bazzi, Department of Electrical Engineering, University of Connecticut, Storrs, CT. Three-phase wound-rotor synchronous motors are less popular than permanent magnet rotor synchronous motors due to the brushes required for the rotor field. Synchronous generators are much more common and available in most existing power plants, as they have excellent frequency and voltage regulation. Synchronous motors have the advantage of almost 0% speed regulation due to the fact that the rotor...
09:02
AC Synchronous Machine Synchronization
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2023
Source: Ali Bazzi, Department of Electrical Engineering, University of Connecticut, Storrs, CT. Three-phase wound-rotor synchronous generators are the main source of electrical power worldwide. They require a prime mover and an exciter in order to generate power. The prime mover can be a turbine spun by fluid (gas or liquid), thus the sources of the fluid can be water running off a dam through a long nozzle, steam from water evaporated using burned coal, etc. Most power plants including coal,...
02:32
Position-effect Variegation
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2020
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
01:19
Machines
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2023
Machines are complex structures consisting of movable, pin-connected multi-force members that work together to transmit forces. One example of a machine is the cutting plier, which is used to cut wires by applying forces to its handles. When equal and opposite forces are exerted on the handles of the cutting plier, they cause the cutting edges to come together and apply equal and opposite reaction forces on the wire, which are greater than the applied forces. A free-body diagram of the...
12:13
Ex Situ Normothermic Machine Perfusion of Donor Livers
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Cited by 21 •
2015
Here we present a protocol describing oxygenated ex situ machine perfusion of donor liver grafts. This article contains a step by step protocol to procure and prepare the liver graft for machine perfusion, prepare the perfusion fluid, prime the perfusion machine and perform oxygenated normothermic machine perfusion of the liver graft.
FAQs
The device repeatedly changes the sample’s orientation relative to Earth’s gravity, causing the direction of the gravity vector to vary over time. Because no single direction remains dominant, the gravitational stimulus experienced by cells or tissues is averaged rather than eliminated. This allows researchers to examine biological responses associated with reduced effective gravity under controlled ground-based conditions.
Rotation around one or more axes changes the sample’s orientation through different spatial directions. This movement supports temporal averaging of the gravity vector and helps create the intended reduced-gravity exposure for the sample. The selected rotational arrangement is therefore an important part of how the system delivers a changing gravitational stimulus during an experiment.
A Random Positioning Machine reduces the effective gravitational stimulus without removing gravity itself, whereas orbital studies provide a different experimental environment. Its value lies in offering a practical ground-based alternative for investigating gravity-sensitive biology. Results can therefore reveal responses to simulated microgravity while remaining distinct from observations made during actual spaceflight or orbital research.
Studies can focus on cell growth, differentiation, tissue organization, fluid behavior, and mechanobiological responses. Mechanobiological responses describe how cells and tissues react to physical forces or mechanical conditions. Examining these outcomes in three-dimensional culture systems helps bioengineers investigate how altered gravitational stimulation may influence tissue development and organization.
Researchers place a biological sample in the machine, expose it to continuous orientation changes, and evaluate the resulting biological response. Depending on the study, measurements may address cell growth, differentiation, tissue organization, fluid behavior, or mechanobiology. This workflow links a controlled simulated-microgravity condition with observable changes in cells, tissues, or three-dimensional cultures.
The method is useful when researchers need to study how reduced gravitational stimulation affects three-dimensional biological systems without relying exclusively on orbital experiments. In tissue engineering, it can support investigations of organization and development. In drug development, altered cell or tissue behavior under simulated microgravity can provide a research context for evaluating biological responses.