scholarly journals Physical model of fluid flows in spacecraft tank

2021 ◽  
Vol 5 (2) ◽  
pp. 212-217
Author(s):  
Vasyl Kovalev ◽  
Volodumur Kalyuzhny ◽  
Vadum Gornostay
Keyword(s):  
Experimental Data ◽  
Liquid Fuel ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Fluid Flows ◽  
High Quality ◽  
Spherical Tank ◽  
Measurement Results ◽  
Spherical Reservoir

The results of an experimental study of liquid fuel flows in the tanks of a spacecraft during its rotation are presented. The analysis of structure and character of flows development on time is carried out, variants of graphic dependences approximation are offered. Graphical diagrams are presented, according to which it is convenient to present a three-dimensional nonlinear picture of non-stationary axisymmetric flow in a spherical reservoir, as well as methods of influencing flows with the help of internal baffles. Estimation of the obtained experimental data probability testifies to the rather high quality of the measurement results and the constructed picture of the currents in the spherical tank with internal baffles.

Thermal Laser Separation – A Novel Dicing Technology Fulfilling the Demands of Volume Manufacturing of 4H-SiC Devices

2015 ◽  
Vol 821-823 ◽  
pp. 528-532 ◽  
Author(s):  
Dirk Lewke ◽  
Karl Otto Dohnke ◽  
Hans Ulrich Zühlke ◽  
Mercedes Cerezuela Barret ◽  
Martin Schellenberger ◽  
...  
Keyword(s):  
Experimental Data ◽  
Process Control ◽  
Tool Wear ◽  
Large Scale ◽  
State Of The Art ◽  
Scale Production ◽  
High Quality ◽  
Large Scale Production ◽  
Laser Separation

One challenge for volume manufacturing of 4H-SiC devices is the state-of-the-art wafer dicing technology – the mechanical blade dicing which suffers from high tool wear and low feed rates. In this paper we discuss Thermal Laser Separation (TLS) as a novel dicing technology for large scale production of SiC devices. We compare the latest TLS experimental data resulting from fully processed 4H-SiC wafers with results obtained by mechanical dicing technology. Especially typical product relevant features like process control monitoring (PCM) structures and backside metallization, quality of diced SiC-devices as well as productivity are considered. It could be shown that with feed rates up to two orders of magnitude higher than state-of-the-art, no tool wear and high quality of diced chips, TLS has a very promising potential to fulfill the demands of volume manufacturing of 4H-SiC devices.

The Experimental Study and Numerical Simulation of Turbulent Flow in Pumping Forebay

2009 ◽  
Author(s):  
Chao Liu ◽  
Jiren Zhou ◽  
Li Cheng
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Turbulent Flow ◽  
Three Dimensional ◽  
Computational Results ◽  
Experiment Study ◽  
Study Results ◽  
Measurement Results ◽  
Good Agreement ◽  
Made In

The experiment study was made to optimize the design of a pumping forebay. The Combined-sills were made in the forebay to eliminate the circulation and vortices of the diffusing flow successfully. The Numerical simulation of three-dimensional turbulent flow is applied on the complicate fore-and-aft flow of sills. The computational results are compared with the measurement results of physical model. The calculated results are in good agreement with the experimental data. The flow pattern is obviously improved. The study results have been applied in the project which gives a uniform approach flow to the pumping sump.

scholarly journals Preparation of Flax Roving for Spinning in Electro-Chemical Activated Solutions

2019 ◽  
Vol 27 (6(138)) ◽  
pp. 34-38
Author(s):  
Pavel Hikolayevich Rudovsky ◽  
Mahammadali Nuraddin Nuriyev ◽  
Ilqar Saleh Recebov
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Hazardous Substances ◽  
High Quality ◽  
Wastewater Pollution ◽  
Treatment Procedures ◽  
Selection Of

A number of environmentally hazardous substances are used in the process of flax roving preparation for spinning. An alternative to them can be the use of electrochemical activated aqueous solutions. However, the metastability of such solutions requires time tracking of their properties’ relaxation. This article pre-sents experimental data on the relaxation of relevant solutions that can be used for a well-founded selection of flax roving treatment procedures to ensure a re-quired quality of flax yarn. It has been experimentally proven that the use of ECA solutions for preparing rovings for spinning allows to obtain high quality yarn as well as significantly reduce wastewater pollution and improve the envi-ronmental situation in the places of their emissions.

Natural three-dimensional display with high quality of reconstructed images based on dense sampling

Optik ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4605-4607 ◽  
Author(s):  
Xunbo Yu ◽  
Xinzhu Sang ◽  
Duo Chen ◽  
Peng Wang ◽  
Xin Gao ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Quality ◽  
Three Dimensional Display ◽  
Dense Sampling

Torsor Evaluation of the Tooth during the Milling Process

2012 ◽  
Vol 186 ◽  
pp. 194-199 ◽  
Author(s):  
Claudiu Bisu ◽  
Elena Luminița Olteanu ◽  
Constantin Minciu ◽  
Miron Zapciu
Keyword(s):  
Three Dimensional ◽  
Milling Process ◽  
Cutting Process ◽  
High Quality ◽  
Milling Cutter ◽  
Position Determination ◽  
Manufacturing Productivity ◽  
Tool Position

Analysis of the torsor evolution in milling process is very important for optimization of the cutting process to achieve high quality of manufacturing, productivity and cost. Our study is based on the analysis of the Mx, My and Mz moments‘ evolution at the tooth tip of the tool during the milling process. A complex experiemntal setup is designed and realized to obtain a three-dimensional response of the mechanical actions. During the tests, the complete torsor of mechanical actions generated by the cutting process were measured by six components dynamometer (forces and moments according to each direction). In this paper a method for tool position determination in milling process is presented, with purpose to transport and evaluate the moments to the tooth tip of the milling cutter.

On Generating High-Quality Random Numbers

2016 ◽  
Vol 26 (02) ◽  
pp. 1750019
Author(s):  
Nazar Abbas Saqib ◽  
Muhammad Zia ◽  
Hasan Mahmood ◽  
Muazzam A. Khan
Keyword(s):  
Random Sequence ◽  
Three Dimensional ◽  
Random Numbers ◽  
Pseudorandom Number Generator ◽  
Statistical Sampling ◽  
High Quality ◽  
High Entropy ◽  
Cell Structures ◽  
2D And 3D

Random numbers are highly used in applications like computer simulation, gambling, statistical sampling and cryptography. Only a high-entropy random source can produce a better quality of random data. In this paper, we work on the generation of high-quality random numbers based on cellular automata (CA). We propose three-dimensional (3D) CA to generate a random sequence. We also propose various enhancements to CA-based pseudorandom number generator (CA-PRNG) and discuss its five variants by using two-dimensional (2D) and 3D CA. We analyze the switching between 2D and 3D CA for the same sequence to achieve high-quality randomness. We provide the architectures, CA rules and the algorithms for all the proposed variants with respect to 2D and 3D cell structures. We have done a software implementation of all the proposed variants and tested their produced sequences by using the internationally accepted standard for random numbers known as DIEHARD. The analysis of our results is made as per the recommendations of ANSI standards. A very similar criteria are applied to compare all the methods. Based on our results we are able to find the best CA-PRNG for producing high-quality random sequence.

scholarly journals Evaluation of Tunnel Contour Quality Index on the Basis of Terrestrial Laser Scanning Data

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Piotr Dybeł ◽  
Katarzyna Dybeł ◽  
Jerzy Cieślik
Keyword(s):  
Cross Sections ◽  
Quality Index ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Terrestrial Laser Scanning ◽  
Modeling Tools ◽  
Measurement Results ◽  
Three Dimensional Models ◽  
Contour Surface

Abstract The Tunnel Contour Quality Index (TCI) is an index established by Kim and Bruland for an effective management of a tunnel contour quality. It is estimated on a basis of measurements of two contour profiles within a single blasting round, using a laser profiler. However, the representativeness of measurement results obtained that way for the assessment of a contour quality of the entire blasting round is disputable. Terrestrial laser scanning (TLS) technology, combined with available numerical surface modeling tools, enables development of three-dimensional models of a monitored surface. The article reports results of TCI calculations based on TLS data. The presented TLS technique is based not only on selected cross-sections of the tunnel contour but also on the description of the morphology of the tunnel contour surface. The case study concerns measurements of the “Mały Luboń” tunnel niche, located in Naprawa, Poland. The TCI values for three blasting rounds were determined in accordance with Kim and Bruland's guidelines and were compared to TCI values determined with the proposed TLS technique. On a basis of this comparison, it can be concluded that the results obtained with the TLS technique are more reliable and representative for description of the contour quality of the entire blasting round than results obtained with the laser profiling technique.

scholarly journals Reducing Waste in 3D Printing Using a Neural Network Based on an Own Elbow Exoskeleton

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5074
Author(s):  
Izabela Rojek ◽  
Dariusz Mikołajewski ◽  
Jakub Kopowski ◽  
Piotr Kotlarz ◽  
Maciej Piechowiak ◽  
...  
Keyword(s):  
Neural Network ◽  
3D Printing ◽  
Neurological Disorders ◽  
Daily Living ◽  
Three Dimensional ◽  
Cost Savings ◽  
High Quality ◽  
Reliable Assessment ◽  
Injection Simulation

Traditional rehabilitation systems are evolving into advanced systems that enhance and improve rehabilitation techniques and physical exercise. The reliable assessment and robotic support of the upper limb joints provided by the presented elbow exoskeleton are important clinical goals in early rehabilitation after stroke and other neurological disorders. This allows for not only the support of activities of daily living, but also prevention of the progression neuromuscular pathology through proactive physiotherapy toward functional recovery. The prices of plastics are rising very quickly, as is their consumption, so it makes sense to optimize three dimensional (3D) printing procedures through, for example, improved artificial intelligence-based (AI-based) design or injection simulation, which reduces the use of filament, saves material, reduces waste, and reduces environmental impact. The time and cost savings will not reduce the high quality of the products and can provide a competitive advantage, especially in the case of thinly designed mass products. AI-based optimization allows for one free print after every 6.67 prints (i.e., from materials that were previously wasted).

scholarly journals Fabrication Methods of the Polygonal Masonry of Large Tightly Fitted Stone Blocks with Curved Surface Interfaces in Megalithic Structures of Peru

2021 ◽  
Author(s):  
Rostislav Lapshin
Keyword(s):  
Small Area ◽  
18Th Century ◽  
Three Dimensional ◽  
Curved Surfaces ◽  
Large Area ◽  
High Quality ◽  
Three Dimensional Objects ◽  
Large Stone ◽  
Clay Model

The article suggests methods that allow creating the most complicated type of polygonal masonry found in Peru. This masonry consists of large stone blocks weighing from several hundred kilograms to several tons fitted close to each other almost without a gap between complicated curved surfaces of large area. The work provides a description of techniques, which apparently were used by builders who arrived from Europe. The techniques under discussion are based on the use of a reduced clay model, 3D-pantograph and replicas. The use of a reduced clay model and a pantograph provides not only the unique appearance and high quality of masonry with large blocks, but also allows to significantly increase the productivity of the builders. As machines copying three-dimensional objects are known since the 18th century, the stone structures under consideration should be dated by that and later time. The remaining simpler types of polygonal masonry with smaller stones or fitted surfaces are almost flat, or stones contact with each other by a small area, or there are significant gaps between stones, are quite consistent with the well-known methods of stone processing of those and earlier years, and, therefore, they do not require any additional explanations.

scholarly journals On IPTV live video coding rate of explore

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Yuanlin Li
Keyword(s):  
Experimental Data ◽  
New Media ◽  
Video Coding ◽  
Work Experience ◽  
High Quality ◽  
Live Video ◽  
Fully Integrated ◽  
Work And Life

<p>With the network of development new media of application have been fully integrated into to We of work and life. How to national?1.2BillionIPTVUser provide high quality of image service is Radio and Television New Media has been thinking Study of topic. The author through years of work experience and a large number of experimental data summarize and verify the to adapt to in IPTV live video rate of standard.</p>

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