Numerical Modelling and Development of New Technical Solutions in Metallurgy and Material Processing

2020 ◽  
Vol 304 ◽  
pp. 113-119
Author(s):  
Alexander Pesin ◽  
Puneet Tandon ◽  
Denis Pustovoytov ◽  
Alexey Korchunov ◽  
Ilya Pesin ◽  
...  
Keyword(s):  
New York ◽  
High Strength ◽  
Theoretical Models ◽  
Experimental Investigations ◽  
Asymmetrical Rolling ◽  
Steel Making ◽  
Plate Rolling ◽  
Rapid Changes ◽  
Almost All ◽  
Technical Solutions

There have been no breakthroughs in ferrous metallurgy for the last 80 years. Automation and digitalization arrived, while the actual steel making processes saw almost no changes. Today, almost all industries experience rapid changes. In 2018 we will see a launch of trains that can travel as fast as1,200 km/h. In 2022 we will see aircrafts capable of flying from London to New York in 1 hour. They already know how to grow human arms and legs. And driverless taxis have become extremely popular. Should we be expecting to see a major breakthrough in metallurgy any time soon? In this paper you will learn about this and other problems, as well as possible ways to solve them. Also, the paper focuses on the results of the development of theory, mathematical models and novel processes, which were helpful in the forming of the ultra-high strength materials by combining the conventional methods of forming such as stamping, plate rolling, plastic bending and asymmetrical rolling. The ultimate aim was to manufacture parts having complex geometries of ultra-high strength sheets. Metalworking techniques like asymmetrical rolling gave rise to very high shear strains and it was used for increasing the strength of the materials. The addition of the incremental sheet forming to the varied combinations of conventional forming processes was used for increasing in the flexibility of the manufacturing process for ultra-high strength. The results of the research project were also encompassing numerical simulation and experimental investigations of the combined process accompanied by the development of the theoretical models for the same.

The Modeling of Flow Concentration in Two-Phase Materials

1976 ◽  
Vol 98 (2) ◽  
pp. 180-189 ◽  
Author(s):  
T. S. Cook ◽  
C. A. Rau ◽  
E. Smith
Keyword(s):  
Development Program ◽  
High Strength ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Micromechanical Modeling ◽  
High Yield ◽  
Experimental Investigations ◽  
Two Phase ◽  
Wide Range ◽  
Materials Research

Many high strength alloys that are developed for arduous operating conditions have essentially a two-phase microstructure that is produced by a precipitation-hardening procedure. However, alloys that are heat-treated to have maximum hardness, often have poor monotonic and poor fatigue fracture characteristics when these are assessed in relation to their high yield strengths, and this imposes limits to their use for service applications. Experimental investigations covering a wide range of precipitation-hardened alloys have shown that the inferior fracture properties are due to plastic deformation being concentrated within narrow zones. Against this background, Pratt & Whitney Aircraft is undertaking a comprehensive theoretical investigation based on the representation of flow concentration by appropriate theoretical models. The general objective is to provide a quantitative understanding of flow concentration, both with respect to its causes and consequences, in terms of both material and externally imposed parameters such as, for example, the state of loading. The aim of the present paper is not to survey the complete problem of flow concentration in the light of the research undertaken to date, but to provide a limited number of examples that illustrate how specific aspects of the problem have been considered using appropriate models to describe the operative physical processes. With the Conference’s objectives in mind, the paper’s general intention is therefore to provide further evidence that micromechanical modeling can be successfully used to relate mechanical behavior with metallurgical parameters, and thereby add further support for the view that such work forms an integral part of any balanced materials research and development program.

scholarly journals Experimental Investigations of Motion of Slide of Selected Pistol Types

2016 ◽  
Vol 7 (4) ◽  
pp. 23-32
Author(s):  
Bartosz FIKUS ◽  
Wojciech KOPERSKI ◽  
Paweł PŁATEK ◽  
Zbigniew SURMA ◽  
Radosław TRĘBIŃSKI
Keyword(s):  
High Speed ◽  
Theoretical Models ◽  
Interaction Force ◽  
Experimental Investigations ◽  
Velocity Versus ◽  
High Speed Camera ◽  
Intensive Phase ◽  
Average Value ◽  
Technical Solutions ◽  
Slide Velocity

In the presented paper, kinematic characteristics of movable parts of investigated pistols have been experimentally determined with application of high speed camera and appropriate software TEMA motion. Results of measurements can be useful in validation of various theoretical models and can reveal the influence of some technical solutions on parameters of motion of selected parts. Obtained curves presenting dependence of slide velocity versus time, allowed for rough estimation of average value of interaction force between slide and frame of the investigated construction. The results of study highlights advantage of HK USP pistol design. The achieved results are from reduction of the value of the mentioned interaction force (approximately 50%) due to elongation of the most intensive phase of slide motion damping process.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

scholarly journals Effectiveness of Face Masks in Reducing the Spread of COVID-19: A Model-Based Analysis

2021 ◽  
pp. 0272989X2110190
Author(s):  
Isabelle J. Rao ◽  
Jacqueline J. Vallon ◽  
Margaret L. Brandeau
Keyword(s):  
New York ◽  
Infected Individual ◽  
Disease Model ◽  
World Health ◽  
Sensitivity Analyses ◽  
Reproductive Number ◽  
Social Distancing ◽  
Health Organization ◽  
Almost All ◽  
Mask Effectiveness

Background The World Health Organization and US Centers for Disease Control and Prevention recommend that both infected and susceptible people wear face masks to protect against COVID-19. Methods We develop a dynamic disease model to assess the effectiveness of face masks in reducing the spread of COVID-19, during an initial outbreak and a later resurgence, as a function of mask effectiveness, coverage, intervention timing, and time horizon. We instantiate the model for the COVID-19 outbreak in New York, with sensitivity analyses on key natural history parameters. Results During the initial epidemic outbreak, with no social distancing, only 100% coverage of masks with high effectiveness can reduce the effective reproductive number [Formula: see text] below 1. During a resurgence, with lowered transmission rates due to social distancing measures, masks with medium effectiveness at 80% coverage can reduce [Formula: see text] below 1 but cannot do so if individuals relax social distancing efforts. Full mask coverage could significantly improve outcomes during a resurgence: with social distancing, masks with at least medium effectiveness could reduce [Formula: see text] below 1 and avert almost all infections, even with intervention fatigue. For coverage levels below 100%, prioritizing masks that reduce the risk of an infected individual from spreading the infection rather than the risk of a susceptible individual from getting infected yields the greatest benefit. Limitations Data regarding COVID-19 transmission are uncertain, and empirical evidence on mask effectiveness is limited. Our analyses assume homogeneous mixing, providing an upper bound on mask effectiveness. Conclusions Even moderately effective face masks can play a role in reducing the spread of COVID-19, particularly with full coverage, but should be combined with social distancing measures to reduce [Formula: see text] below 1. [Box: see text]

PROBING AWAY SIDE JET MODIFICATION WITH THREE PARTICLE CORRELATIONS

2007 ◽  
Vol 16 (07n08) ◽  
pp. 1982-1987
Author(s):  
◽  
N. N. AJITANAND
Keyword(s):  
Spatial Distribution ◽  
Correlation Functions ◽  
Theoretical Models ◽  
The Other ◽  
Experimental Investigations ◽  
Powerful Method ◽  
Particle Correlation ◽  
Low Viscosity ◽  
Jet Modification ◽  
Rhic Data

Recent experimental investigations have focussed on the abnormal spatial distribution of away side jet fragments as signals of significant medium induced effects. A variety of theoretical models including recent string-theory based efforts have supported the notion of Mach Cone like effects in the low viscosity QGP fluid. However, the presence of significant flow fields may deflect the fragmentation direction producing a significantly differing type of jet topology from that of the Mach cone. Three particle correlation functions constitute a powerful method whereby the predominance of one or the other type of mechanism can be differentiated. In this work the use of such an approach will be demonstrated via simulations and the results of its application to RHIC data will be presented.

Interaction of Pipeline Materials with Molten Fluoride Salts

2007 ◽  
Vol 62 (12) ◽  
pp. 769-774
Author(s):  
Tomáš Šimo ◽  
Oldřich Matal ◽  
Lukáś Nesvadba ◽  
Vladimír Dvořák ◽  
Viktor Kanický ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Power Efficiency ◽  
Nuclear Reactor ◽  
Optical Emission ◽  
Theoretical Models ◽  
Emission Spectrometry ◽  
Experimental Investigations ◽  
Salt Melts ◽  
Molten Fluoride ◽  
Fluoride Salts

Molten fluoride salts are very promising carriers for the transport of large amounts of heat for example from a high temperature nuclear reactor to a plant which generates hydrogen by chemical processes or from a nuclear reactor to a heat exchanger being a part of the equipment needed to realize the Brayton cycle with a very high power efficiency. Therefore, in the framework of our project, experimental and theoretical investigations of the interactions of fluoride salts as heat carriers needed as high potential and structural materials for pipelines in order to transport heat at temperatures above 600◦C were started. Experimental investigations of Fe-based and Ni-based materials in molten fluoride salts at high temperatures and with different exposure times were performed. Two components salts (LiF-NaF and NaF-NaBF4) and three components salts (LiF-NaF-ZrF4 and LiF-NaF-RbF) were chosen in the experiments. The salt analysis was focussed on the content of metallic elements before and after the exposure of the samples to the salt melts. It was done by inductively coupled plasma-optical emission spectrometry (ICP-OES) and by titrimetric techniques. The thickness of the material zone affected by the salt melts, characterized by an enriched / reduced content of elements in comparison to the mean original content, and the material attacked zone, characterized by very tiny channels or chains of pores or pits formed preferably at grain boundaries, were the subject of the analysis performed by electron microscopy / microprobe techniques. Theoretical models for the transport of elements in the material samples exposed to salt melts using experimental data were also developed.

Early changes in limb buds of chick embryos after thalidomide treatment

Development ◽  
1966 ◽  
Vol 16 (2) ◽  
pp. 289-300
Author(s):  
A. Jurand
Keyword(s):  
Embryonic Development ◽  
Experimental Investigations ◽  
Experimental Production ◽  
Chick Embryos ◽  
Teratogenic Effects ◽  
Limb Buds ◽  
Experimental Animals ◽  
Almost All ◽  
Thalidomide Treatment

Since the first observations of hypoplastic and aplastic thalidomide deformities in infants (McBride, 1961; Lenz, 1962), the literature on this subject has grown to many hundreds of communications. Experimental investigations in almost all cases have been undertaken to show whether thalidomide and its metabolites have any teratogenic effects in experimental animals. Numerous review papers are available on this subject, e.g. Giroud, Tuchmann-Duplessis & Mercier-Parot (1962), Somers (1963), and Salzgeber & Wolff (1964). Chick embryos did not seem for some time to be suitable for experimental production of typical thalidomide deformities. However, Kemper (1962a, b), Yang, Yang & Liang (1962). Boylen, Home & Johnson (1963) and Leone (1963) have shown that thalidomide can produce a whole range of ectromelian deformities provided that it is introduced into the egg at a particular period of embryonic development.

Vincent Noce, La Collection Egoiste (The Selfish Collector)

2006 ◽  
Vol 13 (1) ◽  
pp. 115-119
Author(s):  
Lyndel V. Prott
Keyword(s):  
New York ◽  
New York Times ◽  
Illicit Trade ◽  
The Family ◽  
Almost All

Vincent Noce, La Collection Egoiste (The Selfish Collector) pp. 328. J. C. Lattès, Paris, 2005. ISBN 2-7096-241-9.Few people who follow cases relating to the illicit trade can have missed the celebrated case of Stéfane Breitwieser, the Alsatian misfit who stole, over a period of 8 or so years, hundreds of objects from museums and churches to squirrel away in his attic rooms, or that of his mother Mireille Stengel, who destroyed almost all of it by disposal in the family garbage bin or by throwing it into a canal. This book, however, shows just how much a dedicated investigative journalist can add to the record, details that are not only useful in trying to understand the mentality of Breitwieser (by no means an isolated case as this account shows) and even more useful in showing the loopholes in the investigations, the lack of coordination between countries, and the sheer ineptitude of many institutions in securing their collections. Noce, editor of the cultural section of the French newspaper Libération, has joined the select company of Karl Meyer (articles in the New York Times) and Peter Watson who have added greatly to our knowledge of how the illicit trade works. French journalists, too, are greatly helping expose the unsavory details of these activities (see Noce's previous book Descente aux Enchères and that of Emmanuel de Roux and Roland-Pierre Paringaud, Razzia sur L'art).

Experimental Study of High Temperature Performance of Steel Suspension Bridge Wires

2019 ◽  
Author(s):  
Jumari A. Robinson ◽  
Adrian Brügger ◽  
Raimondo Betti
Keyword(s):  
Elastic Modulus ◽  
High Temperature ◽  
High Strength Steel ◽  
Cold Working ◽  
High Strength ◽  
Suspension Bridge ◽  
Theoretical Models ◽  
Test Results ◽  
Single Wire ◽  
Steel Wires

<p>The performance of suspension bridges exposed to fire hazards is severely under-studied – so much so that no experimental data exists to quantify the safety of a suspension bridge during or after a major fire event. Bridge performance and safety rely on the integrity of the main cable and its constituent high-strength steel wires. Due to the current lack of experimental high temperature data for wires, the theoretical models use properties and coefficients from data for other types of structural steel. No other structural steel undergoes the amount of cold-working that bridge wire does, and plastic strains from cold-working can be relieved at high temperature, drastically weakening the steel. As such, this work determines the elastic modulus, ultimate strength, and general thermo-mechanical profile of the high-strength steel wires in a range of elevated temperature environments. Specifically, these tests are conducted on a bundle of 61-wires (transient), and at the single wire level (steady-state) at a temperature range of approximately 20-700°C. The test results show an alarmingly high reduction in the elastic modulus and ultimate strength with increased temperature. The degradation shown by experiments is higher than predicted by current theoretical models, indicating that use of high-temperature properties of other types of steel is not sufficient. The test results also show scaling agreement between the single wire and the 61-wire bundle, implying that a full material work up at the single- wire level will accurately inform the failure characterization of the full cable.</p>

PRESENT PROBLEMS PERTAINING TO PATENCY OF THE DUCTUS ARTERIOSUS

PEDIATRICS ◽  
1958 ◽  
Vol 21 (1) ◽  
pp. 70-80
Author(s):  
Mary Allen Engle ◽  
George R. Holswade ◽  
Henry P. Goldberg ◽  
Frank Glenn
Keyword(s):  
New York ◽  
Patent Ductus Arteriosus ◽  
Growth Pattern ◽  
Ductus Arteriosus ◽  
Growth Impairment ◽  
York Hospital ◽  
Abnormal Growth ◽  
Almost All ◽  
Postoperative Observation ◽  
Patent Ductus

The incidence of marked retardation of growth in children with patency of the ductus arteriosus was reviewed in an operative series from the New York Hospital and from the literature. Retardation in growth was present in approximately one-third to one-half of the children. Almost all of the patients in the New York Hospital series with serious growth impairment remained retarded following otherwise successful surgery on the ductus at ages 3 to 14 years. Periods of postoperative observation ranged from 1 to 10 years, averaging 4 years. Possible reasons for persistent impairment of growth are considered. This observation is the basis for a recommendation of early operation for patients with patent ductus arteriosus who become retarded in height and weight. It is anticipated that this will afford a better chance of reversibility of the abnormal growth pattern, if the retardation has not persisted too long during the period of most rapid growth.

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