scholarly journals AN IMPROVED AIR-DRIVEN TYPE OF ULTRACENTRIFUGE FOR MOLECULAR SEDIMENTATION

1937 ◽  
Vol 65 (4) ◽  
pp. 565-586 ◽  
Author(s):  
Johannes H. Bauer ◽  
Edward G. Pickels
Keyword(s):  
High Speed ◽  
Optical Systems ◽  
Centrifugal Field ◽  
Braking System ◽  
Axis Of Rotation ◽  
Protein Molecules ◽  
Transparent Cell ◽  
Definition Of ◽  
Operation Characteristics

1. A description is given of the construction details and operation characteristics of an improved type of air-driven ultracentrifuge operating in vacuum and suitable for the determination of sedimentation constants of protein molecules. 2. The rotor of the centrifuge is made of a forged aluminum alloy; it is oval in shape, measures 185 mm. at its greatest diameter, and weighs 3,430 gm. It carries a transparent cell located at a distance of 65 mm. from the axis of rotation and designed to accommodate a fluid column 15 mm. high. 3. The rotor has been run repeatedly over long periods at a speed of 60,000 R.P.M., which corresponds to a centrifugal force of 260,000 times gravity in the center of the cell. At this speed no deformation of the rotor nor leakage of the cell has been observed. 4. The sharp definition of sedimentation photographs taken at high speed serves to indicate the absence of detectable vibrations in the centrifuge. 5. When a vacuum of less than 1 micron of mercury is maintained in the centrifuge chamber, the rise in the rotor temperature amounts to only 1 or 2°C. after several hours' run at high speed. 6. There has been no evidence of convection currents interfering with normal sedimentation of protein molecules in the centrifugal field. 7. A driving air pressure of about 18 pounds per square inch is sufficient to maintain the centrifuge at a steady speed of 60,000 R.P.M. With a driving pressure of 80 pounds per square inch, it can be accelerated to this speed in less than 20 minutes, and also brought to rest in about the same length of time by the application of the braking system. 8. The adaptation of Svedberg's optical systems to this centrifuge for photographically recording the movement of sedimentation boundaries is described.

Acquisition of 3-D Optical Information

1989 ◽  
Vol 1 (4) ◽  
pp. 255-255
Author(s):  
Masanori Idesawa
Keyword(s):  
Optical Method ◽  
High Speed ◽  
Distance Measurement ◽  
Optical Systems ◽  
Target Point ◽  
Optical Information ◽  
Universal Method ◽  
Distance Information ◽  
Speed Measurement

In order for a machine to have the capacity to operate flexibly in a 3-D environment, it is indispensable for it to be equipped with space information acquisition capability, and tools for distance measurement are in turn indispensable for obtaining space information. Indeed distance measurement is basic and important not only for a robot, but also for science and technology in general. Many methods have been proposed for obtaining distance information, ranging from the mechanical contact type through optical and acoustic to electric and magnetic methods, and many are in practical use. Among them the optical method permits measurement of distance without contact and from a remote position, advantages which have led to it being widely applied. One of the most important principles for measuring distance is the triangulation principle. This permits determination of the position of an object from the distance between two observation points together with the angles in the triangle formed by these two points and a target point on the object. Based on this principle, the detection of one specific point in each of the two images obtained from two sets of image input equipment installed at two observation points permits determination of coordinate values in 3-D space. However, this extraction of the point in the second image corresponding to a specified point in the first image is a very difficult subject of study, and no universal method has been developed. To cope with this, active methods, which evade the problem by applying projection of laser light on the surface of an object to identify a bright point or bright line, are widely used. The special feature articles on obtaining 3-D optical information in this issue present some principles and new trial applications of distance acquisition methods for 3-D information, the optical method in particular. There are three reports on active method optical systems developed for robots. These include (1) a high speed measurement method applying space encoding which employs a liquid crystal lattice to project light in changing lattice patterns onto an object dynamically; (2) realization of high speed measurement through projecting and processing multiple light spots; (3) development of a visual sensor for disaster prevention use which can detect objects in flames and smoke utilizing projection of a CO2 gas laser. These are nearly at the level of operational use and are expected to become visual sensors for robots.

scholarly journals Analysis of the hydraulic conditions of the downhole spillway to possibility of the cavitation

2016 ◽  
Vol 4 ◽  
pp. 9-15
Author(s):  
Zimniukov V.A. ◽  
Zborovskaia M.I. ◽  
Zaitsev A.I.
Keyword(s):  
Working Conditions ◽  
High Speed ◽  
High Water ◽  
Safe Operation ◽  
Hydraulic Conditions ◽  
Definition Of ◽  
Speed Mode ◽  
The Given ◽  
Piezometric Pressure

Studying the work of the deep spillway with segment gate, the presence threshold and asymmetric diffuser outlet part with the determination of possibility appearance of cavitation. As a working case is regarded a pass a high water. Identified the causes of occurrence of cavitation in the offtake spillway tract with the definition of high-speed mode, and the study of piezometric pressure in the calculated alignments, based on data obtained by the model scale 1:50 M spillway. As a result of analysis of the data revealed that under the given working conditions cavitation will occur in the presence of any potential exciter in the pressureless part of the spillway. To ensure safe operation of the spillway is necessary to change the construction of the outlet or change the characteristics of the water flow (for example, use aerators).

scholarly journals Estimation of absolute deformations by changes in distances between the reference points and deformation marks

2018 ◽  
Vol 245 ◽  
pp. 04013 ◽  
Author(s):  
Olga Tsareva ◽  
Ivan Dmitriev ◽  
Yuriy Kornilov
Keyword(s):  
Cultural Heritage ◽  
Reference Points ◽  
Axis Of Rotation ◽  
Displacement Vectors ◽  
Current Observation ◽  
Joint Deformation ◽  
Direction Cosines ◽  
Definition Of ◽  
Angle Of Rotation

The article considers the definition of absolute types of deformations, such as transfer and rotation of a building, using linear spatial intersection. In particular, knowing the distances between strong points and deformation marks, the coordinates of the marks located on the building in the initial and current observation cycles are obtained. Knowing the coordinates of the marks, calculate the displacement vectors of the marks for a certain period of time. The definition of absolute deformations is based on the estimation of the projections of the displacement vectors on the coordinate axes, as well as the direction cosines of the vectors with the coordinate axes. The determination of the direction of displacement is shown for the transference deformation. And how to determine the axis, the distance to this axis and the angle of rotation is shown for rotation deformation. We show for joint deformation of the transfer and rotation how divide it into components and then determine the direction of displacement and the axis of rotation. The results can be used in assessing of absolute deformations buildings of monuments of cultural heritage.

DEFINITION OF THE THERMAL BOUNDARY CONDITIONS AROUND A HIGH SPEED DIESEL ENGINE PISTON

1998 ◽  
Author(s):  
Serge Ravary ◽  
Franck Simon ◽  
Alain Alexandre ◽  
Jean-Bernard Saulnier ◽  
Dominique Joubert
Keyword(s):  
Diesel Engine ◽  
Boundary Conditions ◽  
High Speed ◽  
Thermal Boundary Conditions ◽  
Engine Piston ◽  
High Speed Diesel ◽  
Definition Of

State Failure and the Political Violence Phenomenon: A Comparative Analysis of Iraq and Syria Cases

2016 ◽  
Vol 4 (2) ◽  
pp. 170 ◽  
Author(s):  
K. Eylem Özkaya Lassalle
Keyword(s):  
Cold War ◽  
Political Violence ◽  
State Failure ◽  
The Political ◽  
Collective Violence ◽  
Short Run ◽  
Definition Of ◽  
The Cold War

The concept of failed state came to the fore with the end of the Cold War, the collapse of the USSR and the disintegration of Yugoslavia. Political violence is central in these discussions on the definition of the concept or the determination of its dimensions (indicators). Specifically, the level of political violence, the type of political violence and intensity of political violence has been broached in the literature. An effective classification of political violence can lead us to a better understanding of state failure phenomenon. By using Tilly’s classification of collective violence which is based on extent of coordination among violent actors and salience of short-run damage, the role played by political violence in state failure can be understood clearly. In order to do this, two recent cases, Iraq and Syria will be examined.

DEFINITION OF TIME SPENT ON REPAIR OF BUS TRANSMISSION UNITS TAKING INTO ACCOUNT TECHNOLOGICAL EQUIPMENT RELIABILITY

2020 ◽  
Vol 2020 (9) ◽  
pp. 29-33
Author(s):  
Sergey Bulatov
Keyword(s):  
Negative Impact ◽  
Probabilistic Method ◽  
Technological Equipment ◽  
Quality And Safety ◽  
Transmission Unit ◽  
Equipment Reliability ◽  
Hours Of Work ◽  
Definition Of ◽  
Time Decrease

The paper purpose is the effectiveness estimation in the technological equipment use, taking into account its reliability and productivity for defective transmission units of buses. The problem consists in the determination of time to be spent on repair of bus transmission units taking into account technological equipment reliability. In the paper there is used a probabilistic method for the prediction bus transmission units, and also a method of the dynamics of averages which allow ensuring minimum of costs for units downtime during repair and equipment cost. The need for repair of transmission units (gear box) arises on an average after 650 hours, the average productivity of the bench makes 4.2 bus / hour. The bench fails on the average after 4600 hours of work, the average time of the bench makes 2 hours. In such a way the solution of the problem specified allows analyzing the necessity of time decrease for transmission unit repair to avoid long downtimes of buses in repair areas without negative impact upon high repair quality and safety during the further operation.

Tests of jackhammers (formation of bench techniques)

2020 ◽  
pp. 28-32
Author(s):  
V.S. Vanaev
Keyword(s):  
Impact Energy ◽  
Bench Tests ◽  
Measuring Complex ◽  
Energy Indicators ◽  
Definition Of ◽  
Determination Of Parameters ◽  
Dynamic Indicators

Development of complex determination of parameters of jackhammers at bench tests is studied. The modern support of tests of jackhammers for the purpose of definition of their energy, vibration and noise indicators is considered. Descriptions of the SORP universal bench and UIPU measuring complex are given. Keywords jackhammer, bench, tests, processing object, energy indicators, impact energy, dynamic indicators [email protected]

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