Numerical modeling and analysis of the noncontacting impulse gas face seals

2018 ◽  
Vol 233 (8) ◽  
pp. 1139-1153
Author(s):  
Slawomir Blasiak
Keyword(s):  
Computer Software ◽  
Surface Modifications ◽  
Mechanical Seals ◽  
Face Surface ◽  
Modeling And Analysis ◽  
C Language ◽  
Model Studies ◽  
Face Seals ◽  
Radial Gap ◽  
The Impact

Noncontacting mechanical seals with various kinds of face surface modifications have established their position in the sealing technique. Over the last few years, a lot of works dedicated to the impact of various surface modifications on the dynamics of working rings have been created. This paper presents model studies regarding relatively unknown noncontacting impulse gas face seals. Here, a mathematical model of impulse gas face seals is developed including the nonlinear Reynolds equation and stator dynamics equations, which were solved simultaneously using numerical methods. An original computer software written in C + + language was developed. A number of numerical tests were conducted and the phenomena occurring in the radial gap during seal operation were analyzed. Final conclusions were drawn and several features were indicated characterizing impulse face seals. It should be emphasized that numerical research on this type of seals has not been published yet. The literature usually presents simplified models for the noncompressible medium, which can be solved with the use of analytical methods.

scholarly journals The Impact of Dental Implant Surface Modifications on Osseointegration and Biofilm Formation

2021 ◽  
Vol 10 (8) ◽  
pp. 1641
Author(s):  
Stefanie Kligman ◽  
Zhi Ren ◽  
Chun-Hsi Chung ◽  
Michael Angelo Perillo ◽  
Yu-Cheng Chang ◽  
...  
Keyword(s):  
Dental Implant ◽  
Biofilm Formation ◽  
Bacterial Colonization ◽  
Surface Modifications ◽  
Implant Surface ◽  
Oral Rehabilitation ◽  
Surface Design ◽  
Polyether Ether Ketone ◽  
Dental Implant Surface ◽  
The Impact

Implant surface design has evolved to meet oral rehabilitation challenges in both healthy and compromised bone. For example, to conquer the most common dental implant-related complications, peri-implantitis, and subsequent implant loss, implant surfaces have been modified to introduce desired properties to a dental implant and thus increase the implant success rate and expand their indications. Until now, a diversity of implant surface modifications, including different physical, chemical, and biological techniques, have been applied to a broad range of materials, such as titanium, zirconia, and polyether ether ketone, to achieve these goals. Ideal modifications enhance the interaction between the implant’s surface and its surrounding bone which will facilitate osseointegration while minimizing the bacterial colonization to reduce the risk of biofilm formation. This review article aims to comprehensively discuss currently available implant surface modifications commonly used in implantology in terms of their impact on osseointegration and biofilm formation, which is critical for clinicians to choose the most suitable materials to improve the success and survival of implantation.

Study on the Operation Model of Colleges Network Learning Propaganda and Public Opinion Guidance Based on the Internet

2013 ◽  
Vol 380-384 ◽  
pp. 2104-2108
Author(s):  
Chen Liang Li ◽  
Ming Xia Zhu
Keyword(s):  
Public Opinion ◽  
Information Science ◽  
Internet Technology ◽  
The Internet ◽  
C Language ◽  
Network Learning ◽  
Maximum Value ◽  
Network Transmission ◽  
The Impact ◽  
Important Significance

With the development of computer information science and technology, Internet has a large number of network propaganda and public opinion page every day. Through the network micro message and the micro-blog forwarding, network propaganda and public opinion have the impact on the development and stability of colleges, so the study network propaganda and public opinion has important significance for the development of colleges. Under this background, based on the computer Internet technology, the Internet erection of network propaganda guidance mode are analyzed, and compared with the fuzzy minimum production tree theory and the C language software, the network construction is verified. Finally the iterative process of finding the network transmission is relatively stable, after 800 iterative steps, numerical is slowly increasing, in which the maximum value is about 0.0001. The seven school propaganda is been as the minimum spanning of tree main network, its sum of weighted has been up to 1606.

Physical Origin of the Impact of Different Nanocrystal Surface Modifications on the Performance of CdSe/P3HT Hybrid Solar Cells

2011 ◽  
Vol 115 (29) ◽  
pp. 14111-14122 ◽  
Author(s):  
Nikolay Radychev ◽  
Irina Lokteva ◽  
Florian Witt ◽  
Joanna Kolny-Olesiak ◽  
Holger Borchert ◽  
...  
Keyword(s):  
Solar Cells ◽  
Surface Modifications ◽  
Hybrid Solar Cells ◽  
Physical Origin ◽  
The Impact

Design and testing of energy-efficient heat exchangers for Newtonian and non-Newtonian fluids – A review

2021 ◽  
pp. 095765092110470
Author(s):  
Jayesh P ◽  
Mukkamala Y ◽  
Bibin John
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Internal Surface ◽  
Surface Modifications ◽  
Newtonian Fluids ◽  
Tube Surface ◽  
Pumping Power ◽  
Transfer Enhancement ◽  
The Impact

Heat transfer enhancement, pumping power and weight minimization in enhanced heat exchangers has long been achieved by deploying tubes with internal surface modifications like microgrooves, ribs, fins, knurls, and dimples with and without tube inserts. This article presents a very extensive review of experimental and computational studies on heat transfer enhancement, which covers convectional and unconventional working fluids under different fluid flow conditions. Compound augmentation with tube surface modifications and inserts has yielded enhancements in the overall heat transfer coefficient of over 116% in the fully developed turbulent flow regime. Exotic fluids like nano-coolants deployed in spiral grooved mircofin tubes yielded 196% enhancement in tube side heat transfer rate for concentrations as low as 0.5% by volume, while the thermal efficiency index measuring the overall enhancement in relation to the pumping power was 75%. However, reviews that address the combined effect of unconventional fluids, surface modifications and tube inserts on the overall thermo-hydraulic performance of annular heat exchangers seem to be limited. Further, nano-coolants aren’t frequently used in the process industry. The goal of this study is to document and evaluate the impact of cost-effective and energy-saving passive enhancement techniques such as tube surface modifications, tube inserts, and annular enhancement techniques on annular heat exchangers used in the process industries with Newtonian and non-Newtonian fluids. This review should be useful to engineers, academics and medical professionals working with non-Newtonian fluids and enhanced heat exchangers.

scholarly journals Multi-model study of mercury dispersion in the atmosphere: Vertical distribution of mercury species

2016 ◽  
Author(s):  
Johannes Bieser ◽  
Franz Slemr ◽  
Jesse Ambrose ◽  
Carl Brenninkmeijer ◽  
Steve Brooks ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Atmospheric Chemistry ◽  
Lower Troposphere ◽  
Elemental Mercury ◽  
Mercury Species ◽  
Substantial Impact ◽  
Model Studies ◽  
Model Study ◽  
The Impact ◽  
The Vertical Distribution

Abstract. Atmospheric chemistry and transport of mercury play a key role in the global mercury cycle. However, there are still considerable knowledge gaps concerning the fate of mercury in the atmosphere. This is the second part of a model inter-comparison study investigating the impact of atmospheric chemistry and emissions on mercury in the atmosphere. While the first study focused on ground based observations of mercury concentration and deposition, here we investigate the vertical distribution and speciation of mercury from the planetary boundary layer to the lower stratosphere. So far, there have been few model studies investigating the vertical distribution of mercury, mostly focusing on single aircraft campaigns. Here, we present a first comprehensive analysis based on various aircraft observations in Europe, North America, and on inter-continental flights. The investigated models proved to be able to reproduce the distribution of total and elemental mercury concentrations in the troposphere including inter-hemispheric trends. One key aspect of the study is the investigation of mercury oxidation in the troposphere. We found that different chemistry schemes were better at reproducing observed oxidized mercury (RM) patterns depending on altitude. High RM concentrations in the upper troposphere could be reproduced with oxidation by bromine while elevated concentrations in the lower troposphere were better reproduced by OH and ozone chemistry. However, the results were not always conclusive as the physical and chemical parametrizations in the chemistry transport models also proved to have a substantial impact on model results.

scholarly journals Studying the Impact of Radioactive Charging on the Microphysical Evolution and Transport of Radioactive Aerosols with the TOMAS-RC v1 framework

2017 ◽  
Author(s):  
Petros Vasilakos ◽  
Yong-Ηa Kim ◽  
Jeffrey R. Pierce ◽  
Sotira Yiacoumi ◽  
Costas Tsouris ◽  
...  
Keyword(s):  
Background Radiation ◽  
Atmospheric Transport ◽  
Long Range Transport ◽  
Radioactive Aerosol ◽  
Computationally Efficient ◽  
Radioactive Aerosols ◽  
Model Studies ◽  
Aerosol Mass ◽  
Range Transport ◽  
The Impact

Abstract. Radioactive charging can significantly impact the way radioactive aerosols behave, and as a result their lifetime, but such effects are neglected in predictive model studies of radioactive plumes. The objective of this work is to determine the influence of radioactive charging on the vertical transport of radioactive aerosols in the atmosphere, through its effect on coagulation and deposition, as well as quantifying the impact of this charging on aerosol lifetime. The TwO-Moment Aerosol Sectional (TOMAS) microphysical model was extended to account for radioactive charging effects on coagulation in a computationally efficient way. The expanded model, TOMAS-RC (TOMAS with Radioactive Charging effects), was then used to simulate the microphysical evolution and deposition of radioactive aerosol (containing the isotopes 131I and 137Cs) in a number of idealized atmospheric transport experiments. Results indicate that radioactive charging can facilitate or suppress coagulation of radioactive aerosols, thus influencing the deposition patterns and total amount of radioactive aerosol mass available for long-range transport. Sensitivity simulations to uncertain parameters affirm the potential importance of radioactive charging effects. An important finding is that charging of neutral, coarse mode aerosol from background radiation can reduce coagulation rates and extend its lifetime in the atmosphere by up to a factor of 2.

A Kinematic Model for Mechanical Seals With Antirotation Locks or Positive Drive Devices

1986 ◽  
Vol 108 (1) ◽  
pp. 42-45 ◽  
Author(s):  
I. Green ◽  
I. Etsion
Keyword(s):  
Simple Form ◽  
Kinematic Model ◽  
Mechanical Seals ◽  
Kinematic Constraint ◽  
Face Seals

A kinematic model of mechanical face seals is presented. Two basic seal arrangements are considered: a flexibly mounted stator with antirotation locks, and a flexibly mounted rotor with positive drive devices. The equation of kinematic constraint is derived and presented in a simple form for all the possible types of antirotation or positive drive mechanisms found in practical seals. This simple form is then used to derive the dynamic moments acting on the flexibly mounted element of the seal.

scholarly journals Modern Solution for Fast and Accurate Inventorization of Open-Pit Mines by the Active Remote Sensing Technique—Case Study of Mikoszów Granite Mine (Lower Silesia, SW Poland)

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6853
Author(s):  
Jaroslaw Wajs ◽  
Paweł Trybała ◽  
Justyna Górniak-Zimroz ◽  
Joanna Krupa-Kurzynowska ◽  
Damian Kasza
Keyword(s):  
Computer Software ◽  
Mining Industry ◽  
Ground Surface ◽  
Open Pit ◽  
Mining Operations ◽  
Buffer Zones ◽  
Sw Poland ◽  
The Impact ◽  
Cloud Of Points ◽  
Lower Silesia

Mining industry faces new technological and economic challenges which need to be overcome in order to raise it to a new technological level in accordance with the ideas of Industry 4.0. Mining companies are searching for new possibilities of optimizing and automating processes, as well as for using digital technology and modern computer software to aid technological processes. Every stage of deposit management requires mining engineers, geologists, surveyors, and environment protection specialists who are involved in acquiring, storing, processing, and sharing data related to the parameters describing the deposit, its exploitation and the environment. These data include inter alia: geometries of the deposit, of the excavations, of the overburden and of the mined mineral, borders of the support pillars and of the buffer zones, mining advancements with respect to the set borders, effects of mining activities on the ground surface, documentation of landslide hazards and of the impact of mining operations on the selected elements of the environment. Therefore, over the life cycle of a deposit, modern digital technological solutions should be implemented in order to automate the processes of acquiring, sharing, processing and analyzing data related to deposit management. In accordance with this idea, the article describes the results of a measurement experiment performed in the Mikoszów open-pit granite mine (Lower Silesia, SW Poland) with the use of mobile LiDAR systems. The technology combines active sensors with automatic and global navigation system synchronized on a mobile platform in order to generate an accurate and precise geospatial 3D cloud of points.

scholarly journals Research on Control Characteristics of Three Axis Paraleel Mechanism Based on PIC16f84A

2018 ◽  
Vol 14 ◽  
pp. 31-37
Author(s):  
Alvaro Ruddy Miranda Torrez ◽  
Xin Ji Gan
Keyword(s):  
Parallel Manipulator ◽  
Computer Software ◽  
C Language

This paper is about a parallel manipulator and how to controll it using a microcontroller and c++ language. Is explained wich devices are necesaries and why are the optimous for this project. Everything is followed by a simulation using a computer software.

scholarly journals MODELING AND ANALYSIS OF POLYPROPYLENE FIBER EXTRUSION PROCESS

2021 ◽  
Vol 5 (12) ◽  
Author(s):  
Yousif A.A ◽  
Seedahmed A.I ◽  
Muhab Hassanien S.S
Keyword(s):  
Polypropylene Fiber ◽  
Computer Software ◽  
Processing Parameters ◽  
Extrusion Process ◽  
Design Parameters ◽  
Tensile Drawing ◽  
Zone Length ◽  
Modeling And Analysis ◽  
Screw Length ◽  
Computer Software System

Extrusion processes are widely used in plastic industries that aim to produce advanced solutions for increasingly sophisticated demands for plastics. Processes are not designed based on professional engineering design process, but on trial and error techniques. These two factors affect the extrusion processing parameters. In this study focus will be concentrated on the parameters incorporated in Polypropylene rope extrusion process such as: screw length, screw diameter, metering zone length and flight depth. A model equations were derived considering the swelling occurs for the extruded fibers and the tensile drawing of fiber. The authenticated design parameters was derived and a model useful to simulate any given process successfully was resulted in a form of computer software system.

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