Characteristic Features of the Thermomechanics of Gas Flows in the Piston Engine Outlet under Various Gas-Dynamical Conditions

2021 ◽  
Author(s):  
L. V. Plotnikov ◽  
B. P. Zhilkin
Keyword(s):  
Gas Flows ◽  
Piston Engine ◽  
Characteristic Features

Operation Regimes of Fluidized Beds

1995 ◽  
Vol 60 (1) ◽  
pp. 1-33 ◽  
Author(s):  
Miloslav Hartman ◽  
Zdeněk Beran ◽  
Karel Svoboda ◽  
Václav Veselý
Keyword(s):  
Fluidized Beds ◽  
State Of The Art ◽  
Particle Density ◽  
Gas Flows ◽  
Pneumatic Conveying ◽  
Operation Conditions ◽  
Characteristic Features ◽  
Bubbling Beds ◽  
Bubble Regime ◽  
Regime Characteristic

The state of the art has been reviewed in the analysis and description of flow or contacting pattern in gas-solid contacting units where a gas flows upwards through a bed of solids. The flow regime or contacting mode varies widely, depending on the particle size, particle density, gas density, gas viscosity, gas velocity and column geometry. The influence of such variables is reflected in the particle classification schemes and regime diagrams to cover the operation regions of common gas-solid reactors and contactors. In general, fluidized beds can be operated in six different regimes: particulate (homogeneous) fluidization, bubbling fluidization, slugging fluidization, turbulent fluidization, fast fluidization and pneumatic conveying. The bubbling beds can be further classified into three different modes of contacting: fast bubble regime, slow bubble regime and rapidly growing bubble regime. Characteristic features of all the regimes as well as the transitions between them are discussed. Current research interests, supported by practical needs, are oriented toward the operation conditions and contactor geometry of high velocity units.

scholarly journals Heat transfer intensity of pulsating gas flows in the exhaust system elements of a piston engine

2019 ◽  
Vol 124 ◽  
pp. 01015
Author(s):  
L. V. Plotnikov ◽  
Y. M. Brodov ◽  
M. O. Misnik
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Experimental Studies ◽  
Exhaust System ◽  
Scale Model ◽  
Gas Flows ◽  
Exhaust Pipe ◽  
Piston Engine ◽  
Gas Dynamic ◽  
Valve Assembly

Internal combustion engines are the most common sources of energy among heat engines. Therefore, the improvement of their design and workflow is an urgent task in the development of world energy. Thermal-mechanical perfection of the exhaust system has a significant impact on the technical and economic performance of piston engines. The article presents the results of experimental studies of gas-dynamics and heat exchange of pulsating gas flows in the exhaust system of a piston engine. Studies were carried out on a full-scale model of a single-cylinder engine. The article describes the instrument-measuring base and methods of experiments. The heat transfer intensity was estimated in different elements of the exhaust system: the exhaust pipe, the channel in the cylinder head, the valve assembly. Heat transfer studies were carried out taking into account the gas-dynamic nonstationarity characteristic of gas exchange processes in engines. The article presents data on the influence of gas-dynamic and regime factors on the heat transfer intensity. It is shown that the restructuring of the gas flow structure in the exhaust system occurs depending on the engine crankshaft speed, this has a significant impact on the local heat transfer coefficient. It has been established that the heat transfer intensity in the valve assembly is 2-3 times lower than in other elements of the exhaust system.

Ultrastructural modification of cellular interactions in cancer tumor

1978 ◽  
Vol 36 (2) ◽  
pp. 318-319
Author(s):  
N. P. Dmitrieva
Keyword(s):  
Cancer Cells ◽  
Human Thyroid ◽  
Adjacent Cell ◽  
Main Role ◽  
Cellular Interactions ◽  
Electron Microscopic ◽  
Cancer Tumor ◽  
Normal Human ◽  
Characteristic Features

One of the most characteristic features of cancer cells is their ability to metastasia. It is suggested that the modifications of the structure and properties of cancer cells surfaces play the main role in this process. The present work was aimed at finding out what ultrastructural features apear in tumor in vivo which removal of individual cancer cells from the cell population can provide. For this purpose the cellular interactions in the normal human thyroid and cancer tumor of this gland electron microscopic were studied. The tissues were fixed in osmium tetroxide and were embedded in Araldite-Epon.In normal human thyroid the most common type of intercellular contacts was represented by simple junction formed by the parallelalignment of adjacent cell membranees leaving in between an intermembranes space 15-20 nm filled with electronlucid material (Fig. 1a). Sometimes in the basal part of cells dilatations of the intercellular space 40-50 nm wide were found (Fig. 1a). Here the cell surfaces may form single short microvilli.

In Situ Observation of Catalyzed Gasification of Graphite by Nickel

1981 ◽  
Vol 39 ◽  
pp. 76-77
Author(s):  
R. T. K. Baker ◽  
R. D. Sherwood
Keyword(s):  
Objective Lens ◽  
In Situ Observation ◽  
Gas Flows ◽  
Catalytic Gasification ◽  
Television Camera ◽  
Viewing Screen ◽  
Fuels And Chemicals ◽  
Gasification Of Carbon ◽  
Transmission Microscope

The catalytic gasification of carbon at high temperature by microscopic size metal particles is of fundamental importance to removal of coke deposits and conversion of refractory hydrocarbons into fuels and chemicals. The reaction of metal/carbon/gas systems can be observed by controlled atmosphere electron microscopy (CAEM) in an 100 KV conventional transmission microscope. In the JEOL gas reaction stage model AGl (Fig. 1) the specimen is positioned over a hole, 200μm diameter, in a platinum heater strip, and is interposed between two apertures, 75μm diameter. The control gas flows across the specimen and exits through these apertures into the specimen chamber. The gas is further confined by two apertures, one in the condenser and one in the objective lens pole pieces, and removed by an auxiliary vacuum pump. The reaction zone is <1 mm thick and is maintained at gas pressure up to 400 Torr and temperature up to 1300<C as measured by a Pt-Pt/Rh 13% thermocouple. Reaction events are observed and recorded on videotape by using a Philips phosphor-television camera located below a hole in the center of the viewing screen. The overall resolution is greater than 2.5 nm.

Development of 200kV ultrahigh-resolution analytical electron microscope

1989 ◽  
Vol 47 ◽  
pp. 108-109
Author(s):  
T. Kaneyama ◽  
M. Naruse ◽  
Y. Ishida ◽  
M. Kersker
Keyword(s):  
Electron Microscope ◽  
Optical Constants ◽  
Materials Science ◽  
Objective Lens ◽  
The Finite Element Method ◽  
Ultrahigh Resolution ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Characteristic Features ◽  
Better Than

In the field of materials science, the importance of the ultrahigh resolution analytical electron microscope (UHRAEM) is increasing. A new UHRAEM which provides a resolution of better than 0.2 nm and allows analysis of a few nm areas has been developed. [Fig. 1 shows the external view] The followings are some characteristic features of the UHRAEM.Objective lens (OL)Two types of OL polepieces (URP for ±10' specimen tilt and ARP for ±30' tilt) have been developed. The optical constants shown in the table on the next page are figures calculated by the finite element method. However, Cs was experimentally confirmed by two methods (namely, Beam Tilt method and Krivanek method) as 0.45 ∼ 0.50 mm for URP and as 0.9 ∼ 1.0 mm for ARP, respectively. Fig. 2 shows an optical diffractogram obtained from a micrograph of amorphous carbon with URP under the Scherzer defocus condition. It demonstrates a resolution of 0.19 nm and a Cs smaller than 0.5 mm.

Tolerance is theoretical and practical principles

1996 ◽  
pp. 13-23
Author(s):  
Mykhailo Babiy
Keyword(s):  
Religious Diversity ◽  
The Other ◽  
Nodal Points ◽  
Characteristic Features ◽  
The One ◽  
Ukrainian Society

Political ideological pluralism, religious diversity are characteristic features of modern Ukrainian society. On the one hand, multiculturalism, socio-political, religious differentiation of the latter appear as important characteristics of its democracy, as a practical expression of freedom, on the other - as a factor that led to the deconsocialization of society, gave rise to "nodal points" of tension, confrontational processes, in particular, in political and religious spheres.

Hard and light gamification in education: Which one to choose?

2020 ◽  
Vol 1 (1) ◽  
pp. 20-27
Author(s):  
E. V. Karmanova ◽  
V. A. Shelemetyeva
Keyword(s):  
Computer Games ◽  
Educational Process ◽  
Course Development ◽  
Learning Technology ◽  
Training Course ◽  
Resource Requirements ◽  
E Learning ◽  
Characteristic Features ◽  
Game Elements

The article is devoted to the implementation of gamification methods in the educational process. The characteristic features of light and hard gamification are presented. The appropriateness of using gamification when applying e-learning technology is considered. Classification of courses based on hard gamification taking into account the technological features of development is proposed: courses-presentations, courses — computer games, VR/AR courses. The article also illustrates the use of various game elements of easy gamification using the example of the module “Level up! — Gamification” of the Moodle LMS. The capabilities of this module can be used in an electronic course by any teacher who has the skills of working with the Moodle.The authors present the analysis of the development of a training course in sales techniques using hard and light gamification technologies, where the course development was assessed for its complexity, manufacturability, and resource requirements. The results of the analysis showed that the development of courses using hard gamification requires much more financial and time-consuming than the development of courses using light gamification.The article evaluates the results of the educational intensiveness intense “Island 10–22”, held in July 2019 in Skolkovo, in which 100 university teams, teams of research and educational centers, teams of schoolchildren — winners of competitions, olympiads, hackathons (“Young Talents”) participated. The results of the intense confirmed the effectiveness of the use of light gamification methods in adult training. Thus, the conclusions presented in the article reveal a number of advantages that light gamification has in comparison with hard gamification.

Budget as an Instrument of Reproduction of Bureaucracy in Russia

2006 ◽  
pp. 87-96
Author(s):  
Yu. Shvetsov
Keyword(s):  
The State ◽  
Economic Consequences ◽  
Material Base ◽  
Characteristic Features

The article considers the problem of bureaucratisation of the state and the most important social and economic consequences of this phenomenon. The essence of bureaucracy has been revealed, characteristic features of its functioning in Russia have been analyzed; the material base of bureaucracy and its dominating status in the society have been substantiated. The conclusion has been made that the process of changing the role of the budget to serve the interests of bureaucracy is being accomplished.

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