Study of the stability of the geometric dimensions of wax models of GTE blades using rapid prototyping technology

2020 ◽  
Vol 919 ◽  
pp. 022052
Author(s):  
R A Vdovin
Keyword(s):  
Rapid Prototyping ◽  
The Stability ◽  
Wax Models

Novel antimicrobial materials designed for the 3D printing of medical devices used during the COVID-19 crisis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Samuel Furka ◽  
Daniel Furka ◽  
Nitin Chandra Teja Chandra Teja Dadi ◽  
Patrik Palacka ◽  
Dominika Hromníková ◽  
...  
Keyword(s):  
3D Printing ◽  
Rapid Prototyping ◽  
Medical Devices ◽  
Hybrid Material ◽  
Weight Ratio ◽  
Layered Silicate ◽  
Content Type ◽  
Antimicrobial Materials ◽  
The Stability ◽  
Designed Materials

Purpose This study aims to describe the preparation of antimicrobial material usable in 3D printing of medical devices. Despite the wealth of technological progress at the time of the crisis caused by SARS-CoV-2 virus: Virus that causes current Pandemic situation (COVID-19), the global population had long been exposed beforehand to an acute absence of essential medical devices. As a response, a new type of composite materials intended for rapid prototyping, based on layered silicate saponite (Sap), antimicrobial dye phloxine B (PhB) and thermoplastics, has been recently developed. Design/methodology/approach Sap was modified with a cationic surfactant and subsequently functionalized with PhB. The hybrid material in powder form was then grounded with polyethylene terephthalate-glycol (PETG) or polylactic acid (PLA) in a precisely defined weight ratio and extruded into printing filaments. The stability and level of cytotoxicity of these materials in various physiological environments simulating the human body have been studied. The applicability of these materials in bacteria and a yeast-infected environment was evaluated. Findings Ideal content of the hybrid material, with respect to thermoplastic, was 15 weight %. Optimal printing temperature and speed, with respect to maintaining antimicrobial activity of the prepared materials, were T = 215°C at 50 mm/s for PETG/SapPhB and T = 230°C at 40 mm/s for PLA/SapPhB. 3 D-printed air filters made of these materials could keep inner air flow at 63.5% and 76.8% of the original value for the PLA/SapPhB and PETG/SapPhB, respectively, whereas the same components made without PhB had a 100% reduction of airflow. Practical implications The designed materials can be used for rapid prototyping of medical devices. Originality/value The new materials have been immediately used in the construction of an emergency lung ventilator, Q-vent, which has been used in different countries during the COVID-19 crisis.

Developing a methodology for analysis and manufacturing of proximal interphalangeal (PIP) joint using rapid prototyping technique

2015 ◽  
Vol 21 (4) ◽  
pp. 449-460 ◽  
Author(s):  
Emad Abouel Nasr ◽  
Abdurahman Mushabab Al-Ahmari ◽  
Hazem Alkhawashki ◽  
Abdulsalam Altamimi ◽  
Mohammed Alkhuraisi
Keyword(s):  
Rapid Prototyping ◽  
Range Of Motion ◽  
Relative Motion ◽  
Equivalent Stress ◽  
Proximal Interphalangeal Joint ◽  
Interphalangeal Joint ◽  
Implant Design ◽  
Content Type ◽  
Stress And Deformation ◽  
The Stability

Purpose – The purpose of this paper is to design and analyze four proximal interphalangeal joint (PIP) prosthesis thorough finite element analysis (FEA) and fabricate them using rapid prototyping (RP) technique. Arthritis of the finger joints is an important pathology of the hand. Major complaints in arthritis are stiffness, deformity and severe pain. The pain is due to the inflammatory process that occurs due to pathology, which involves joint degeneration, synovial swelling and ligament and muscle stiffness. Among the surgical treatment of arthritis is Arthroplasty which involves replacing the diseased joint with an artificial joint. Design/methodology/approach – In this paper, four proximal interphalangeal joint (PIP) prostheses are designed, analyzed using FEA and fabricated using rapid prototyping technique. Four different prostheses “BM”, “IMP”, “IMP2” and “FINS” are designed using CATIA software and tested by normal daily functions such as grasp, key pinch and tip pinch tests using FEA to analyze the results based on their stress and deformation. Finally, the prostheses are fabricated using electron beam melting technology. Findings – This paper examined and analyzed the relative motion of PIP designs using FEA by applying varying loads to check the stability and range of motion of the PIP implant. The ANSYS summary results were analyzed depending on the minimal results of equivalent stress and deformation from the taken tests that have happened on the designed prosthesis. The results conclude that, in the grasp test, the minimal equivalent stress and deformation have happened on the “BM” and “IMP2” implants. Furthermore, in the key pinch test, minimal equivalent stress and deformation occurred on the “FINS” implant, and finally, in the tip pinch, minimal equivalent stress occurred on the “FINS” and minimal deformation has happened on the “IMP2” implant. Research limitations/implications – These results conclude that both “IMP2” and “FINS” share the minimum results in the taken tests, and this shows that these implants may be further studied brainstormed upon to aid innovation of a better implant design that shares both of these implants’ features and shape. Nevertheless, testing in an in vivo or in vitro model to prove more of the effectiveness of these implants should be taken into consideration, and to test how the prostheses will function in an actual environment, a simulated hand can be designed and made to discover the true forces and mechanics of the fingers and the hands with the prosthesis that is implanted, as well as to know if the hand works properly. Originality/value – This paper examined and analyzed the relative motion of PIP designs using FEA by applying varying loads to check the stability and range of motion of the PIP implant.

scholarly journals Features of Use of Rapid Prototyping Technology in the Manufacture of Wax Models of GTE Turbine Blades

2021 ◽  
Vol 346 ◽  
pp. 03106
Author(s):  
R.A. Vdovin
Keyword(s):  
3D Printing ◽  
Rapid Prototyping ◽  
Technological Process ◽  
Turbine Blades ◽  
Statistical Information ◽  
Tolerance Range ◽  
Main Design ◽  
Total Shrinkage ◽  
Wax Models ◽  
Shrinkage Coefficient

The paper presents the main results related to the peculiarities of using 3D printing technology and methods of rapid prototyping in the manufacture of wax models of blades of a GTE turbine. The main design solutions that must be used in the design of a blade blank are presented in detail: the total shrinkage coefficient, equidistant rolling of the airfoil profile, allowance along tract surfaces, radial fillets, and a number of others. The results of control of geometric dimensions of the turbine blade blanks at the corresponding stages of the technological process showed deviations from the nominal value within the tolerance range for the executable dimensions, and the statistical information from the measurement of an experimental batch of wax models of blade blanks showed stability of the silicone tooling and ability to manufacture a series of wax models of the blades in the amount of 100 pieces when using one mold.

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

Symmetric Multistep Methods Revisited: II. Numerical Experiments

1999 ◽  
Vol 173 ◽  
pp. 309-314 ◽  
Author(s):  
T. Fukushima
Keyword(s):  
Multistep Methods ◽  
Computational Time ◽  
Integration Time ◽  
Implicit Methods ◽  
Symmetric Methods ◽  
Celestial Bodies ◽  
The Stability ◽  
Predictor Corrector ◽  
Symmetric Multistep Methods ◽  
Integration Errors

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.

Uniformity of Magnification from Different Electron Microscopes

1967 ◽  
Vol 25 ◽  
pp. 32-33
Author(s):  
Godfrey C. Hoskins ◽  
V. Williams ◽  
V. Allison
Keyword(s):  
Diffraction Grating ◽  
The Other ◽  
Carbon Replica ◽  
Electron Microscopes ◽  
The Stability

The method demonstrated is an adaptation of a proven procedure for accurately determining the magnification of light photomicrographs. Because of the stability of modern electrical lenses, the method is shown to be directly applicable for providing precise reproducibility of magnification in various models of electron microscopes.A readily recognizable area of a carbon replica of a crossed-line diffraction grating is used as a standard. The same area of the standard was photographed in Phillips EM 200, Hitachi HU-11B2, and RCA EMU 3F electron microscopes at taps representative of the range of magnification of each. Negatives from one microscope were selected as guides and printed at convenient magnifications; then negatives from each of the other microscopes were projected to register with these prints. By deferring measurement to the print rather than comparing negatives, correspondence of magnification of the specimen in the three microscopes could be brought to within 2%.

Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength

1970 ◽  
Vol 28 ◽  
pp. 444-445
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
Oxide Particle ◽  
Oxide Phase ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Oxide Particles ◽  
The Stability

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

Formation and Structure of Casein Micelles in Lactating Mammary Tissue

1970 ◽  
Vol 28 ◽  
pp. 150-151
Author(s):  
Robert J. Carroll ◽  
Marvin P. Thompson ◽  
Harold M. Farrell
Keyword(s):  
Size Distribution ◽  
G Protein ◽  
Milk Proteins ◽  
Mammary Tissue ◽  
Colloidal System ◽  
Casein Micelles ◽  
The Stability

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.

TEM Analysis of Long-Period Polytypes in SiC—S

1976 ◽  
Vol 34 ◽  
pp. 630-631
Author(s):  
S. Shinozaki ◽  
J. W. Sprys
Keyword(s):  
Electron Diffraction ◽  
Isothermal Annealing ◽  
Tem Analysis ◽  
Long Period ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Structural Lattice ◽  
The Stability ◽  
Continuous Curves

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.

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