Fluid Mechanics of Slot Coating in Layered Manufacturing

2001 ◽  
Author(s):  
M. Haberer ◽  
G. Zak ◽  
C. B. Park ◽  
M. Paraschivoiu ◽  
B. Benhabib
Keyword(s):  
Fluid Mechanics ◽  
Cross Sections ◽  
Manufacturing System ◽  
Layered Composite ◽  
Layered Manufacturing ◽  
Thin Layers ◽  
Prototype System ◽  
Slot Coating ◽  
Parts Manufacturing ◽  
The Relationship

Abstract This paper addresses the fluid mechanics of the slot-coating process within the context of the layered manufacturing system. The investigation was carried out to assist with the design of a novel slot-coating-based liquid-layer-formation subsystem. This subsystem, when used as a part of a lithography-based Rapid Layered Composite parts Manufacturing (RLCM) system, successfully solves some of the difficulties encountered in the formation of thin layers from a highly viscous fibre-photopolymer composite liquid. In addition to an analytical model, the paper presents a numerical model based on a volume of fluid (VOF) algorithm. The algorithm allows (1) solution of non-steady-state problems, (2) tracking of the free surface of the fluid undergoing large deformations, and (3) easy modification of model’s domain to facilitate experimentation with coater geometry. Results from a set of simulated experiments are reported which show the relationship between the liquid coat height and several design and process parameters. Examination of cross-sections of test parts built on an RLCM prototype system confirmed the ability of the new coater design to form solid layers of good quality.

Fluid mechanics of slot-coating in photopolymer-based rapid composites manufacturing

2003 ◽  
Vol 217 (1) ◽  
pp. 65-79 ◽  
Author(s):  
M Haberer ◽  
G Zak ◽  
C B Park ◽  
M Paraschivoiu ◽  
B Benhabib
Keyword(s):  
Fluid Mechanics ◽  
Cross Sections ◽  
Large Deformations ◽  
Layered Composite ◽  
Thin Layers ◽  
Prototype System ◽  
Analysis Tool ◽  
Composites Manufacturing ◽  
Slot Coating ◽  
Parts Manufacturing

This paper describes the fluid mechanics of the slot-coating process in the context of rapid layered manufacturing. It has been conjectured that slot-coating would successfully address a number of common difficulties encountered in the formation of thin layers from a highly viscous fibre—photopolymer composite liquid. The objective of the present study was therefore the development of an engineering analysis tool to assist with the design of a slot-coating-based liquid layer formation mechanism for use as an integral part of a lithography-based rapid layered composite parts manufacturing (RLCM) system. In addition to an analytical model, the paper presents a numerical model based on a volume-of-fluid (VOF) algorithm. This algorithm allows (a) solution of non-steady-state problems, (b) tracking of the free surface of the fluid undergoing large deformations and (c) easy modification of the model's domain to facilitate experimentation with coater geometry. Results from a set of simulated experiments establish a relationship between the liquid-coat height and several design and process parameters. Physical examination of cross-sections of several test parts built on an RLCM prototype system in the authors’ laboratory confirmed the ability of the new coater design to form solid layers of good quality, as predicted by the numerical simulations.

Design of a Slot-Coater-Based Layered-Composites Manufacturing System

2003 ◽  
Vol 125 (3) ◽  
pp. 564-576 ◽  
Author(s):  
M. Haberer ◽  
G. Zak ◽  
C. B. Park ◽  
B. Benhabib
Keyword(s):  
Liquid Layer ◽  
Design Theory ◽  
Glass Fibers ◽  
Layered Composite ◽  
Fiber Content ◽  
Thin Layers ◽  
Layer Formation ◽  
High Fiber ◽  
Axiomatic Design Theory ◽  
Parts Manufacturing

This paper addresses the reinforcement of photopolymers, through the addition of short glass fibers, for Rapid Layered Composite parts Manufacturing (RLCM). Novel designs for an (external) fiber-resin-mixing subsystem and a (slot-coating-based) liquid-layer-formation subsystem are presented. These subsystems, when used as integral parts of a lithography-based RLCM system, successfully cope with typical difficulties encountered in the formation of thin layers from a highly viscous fiber-photopolymer composite liquid. Axiomatic Design theory was utilized for the analysis of both subsystem designs. Verification experiments run on an RLCM system confirmed (i) the ability of the fiber-resin-mixing subsystem to supply liquid composite with specified fiber content and to avoid fiber degradation through breakage, as well as (ii) the ability of the liquid-layer-formation subsystem to form solid layers with high fiber content and of uniform thickness.

THERMO-INDUCED SHIFT OF PLASMON ENERGY IN ELECTRON LOSS SPECTRA FOR THE ORDERING Pt80Co20(111) ALLOY SURFACE

2009 ◽  
Vol 16 (02) ◽  
pp. 249-258 ◽  
Author(s):  
V. A. TINKOV ◽  
M. A. VASYLYEV
Keyword(s):  
Energy Loss ◽  
Surface Plasmon ◽  
Energy Shift ◽  
Primary Electron ◽  
Thin Layers ◽  
Plasmon Energy ◽  
Concentration Depth Profile ◽  
Bulk Plasmon ◽  
Electron Energy Loss ◽  
The Relationship

Electron energy loss spectroscopy has been used for the investigation of the surface and bulk plasmon excitations depending on the heating in the ultra-thin layers of ordering Pt 80 Co 20(111) alloy from the primary electron beam energies E0 ranging from 200 to 650 eV. Thermo-induced shift of plasmon energy and damping of intensity line of the surface plasmon relative to the bulk plasmon were observed. With an increase in alloy heating, the energy of surface and bulk plasmons is shifted with lowering energy in the whole range E0 and the higher the temperature the higher the shifts of plasmon energy. The physical processes that can influence on the energy shift of plasmon oscillations in the energy loss spectra at heating are considered. The relationship between the damping of oscillating concentration depth profile and the surface plasmon damping at heating was established.

scholarly journals Investigations on Torsion of the Two-Chords Single Laced Members

2017 ◽  
Vol 25 (2) ◽  
pp. 147-160
Author(s):  
Paweł Lorkowski ◽  
Bronisław Gosowski
Keyword(s):  
Cross Sections ◽  
Experimental Studies ◽  
The Finite Element Method ◽  
Second Moment ◽  
Steel Columns ◽  
Numerical Studies ◽  
Traction Network ◽  
Railway Traction ◽  
Parametric Analyses ◽  
The Relationship

Abstract The paper presents experimental and numerical studies to determine the equivalent second moment of area of the uniform torsion of the two-chord steel single laced members. The members are used as poles of railway traction network gates, and steel columns of framed buildings as well. The stiffness of uniform torsion of this kind of columns allows to the determine the critical loads of the spatial stability. The experimental studies have been realized on a single - span members with rotation arrested at their ends, loaded by a torque applied at the mid-span. The relationship between angle of rotation of the considered cross-section and the torque has been determined. Appropriate numerical model was created in the ABAQUS program, based on the finite element method. A very good compatibility has been observed between experimental and numerical studies. The equivalent second moment of area of the uniform torsion for analysed members has been determined by comparing the experimental and analytical results to those obtained from differential equation of non-uniform torsion, based on Vlasov’s theory. Additionally, the parametric analyses of similar members subjected to the uniform torsion, for the richer range of cross-sections have been carried out by the means of SOFiSTiK program. The purpose of the latter was determining parametrical formulas for calculation of the second moment of area of uniform torsion.

scholarly journals Fluid boundaries shaping using the method of kinetic balance

2006 ◽  
Vol 10 (4) ◽  
pp. 153-162
Author(s):  
Miroslav Benisek ◽  
Svetislav Cantrak ◽  
Milos Nedeljkovic ◽  
Djordje Cantrak ◽  
Dejan Ilic ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Mechanics ◽  
Cross Sections ◽  
Hydraulic Engineering ◽  
Optimum Shape ◽  
Curved Channels ◽  
Unsteady Fluid Flow ◽  
Unsteady Fluid ◽  
Flow Boundaries ◽  
Dead Water

Fluid flow in curved channels with various cross-sections, as a common problem in theoretical and applied fluid mechanics, is a very complex and quite undiscovered phenomenon. Defining the optimum shape of the fluid flow boundaries, which would ensure minimum undesirable phenomena, like "dead water" zones, unsteady fluid flow, etc., is one of the crucial hydraulic engineering?s task. Method of kinetic balance is described and used for this purpose, what is illustrated with few examples. .

Estimating discharge in rivers through the combined use of dimensionless isovels and point velocity measurements

2017 ◽  
Vol 48 (3) ◽  
pp. 616-633 ◽  
Author(s):  
G. Farina ◽  
S. Alvisi ◽  
M. Franchini
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Accurate Estimation ◽  
Velocity Measurements ◽  
Combined Use ◽  
Point Velocity ◽  
New Formulation ◽  
The Relationship ◽  
River Cross Section

This paper presents a procedure for estimating discharge in a river cross-section based on the combined use of dimensionless isovels and point velocity measurements. Specifically, taking the Biot–Savart law on the magnetic field induced by an electric current in a wire as their basis as already done by other researchers, the authors propose a new formulation of the relationship characterizing the effect of the wetted perimeter on the range of velocities in a cross-section in order to take explicit account of roughness, expressed by means of Manning's coefficient. Once appropriately nondimensionalized, the isoeffect contours can be read as dimensionless isovels. Assuming in situ velocity measurements are available, discharge at a cross-section can be computed using two different methods. The proposed procedure was applied to six case studies characterized by river cross-sections which differed greatly from one another. The results show that the two methods proposed for estimating discharge lead to equivalent outcomes, and in all the cases the procedure as a whole enables a sufficiently accurate estimation of discharge, even when it is based on a limited number of velocity measurements or on the measurement of maximum surface-water velocity alone.

scholarly journals Establishing Evaluation Criteria for Digital Dental Simulation Systems and the Differences between Software and Evaluators

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Masaki Morishita
Keyword(s):  
Undergraduate Students ◽  
Cross Sections ◽  
Dental Education ◽  
Evaluation Criteria ◽  
Dental Students ◽  
Software Evaluation ◽  
Digital Devices ◽  
Tooth Preparation ◽  
The Relationship ◽  
Simulation Systems

Purpose: Cavity and tooth preparation are essential curriculum components in dental education for undergraduate students, and faculty staff determine whether the standard of the work is acceptable. However, evaluators are inevitably subject to variability and bias, so quantification of the evaluation is desirable. Therefore, various digital devices have been developed to quantify evaluations, such as SURFLACER, Simodont, and DentSim. In this study, we aimed to investigate the use of evaluation software and to compare human evaluation with software evaluation using a new digital dental education device with a realtime evaluation function. Material and Method: Dental students prepared a full metal crown on an artificial mandibular left first molar, which was evaluated by the software and a human evaluator (a dentist). Results: The results showed that the software evaluation was more suitable with eight cross-sections than with four crosssections. The dentist evaluated the same teeth according to a set of evaluation criteria, but there were no statistically significant differences in any of the evaluation items. Finally, multivariate analysis was conducted to assess the relationship between the software evaluation using eight cross-sections and the human evaluator using dummy variables, and it revealed that the margin form evaluation by the dentist was a significant explanatory variable for the score by the software. Conclusion: This preliminary study is the first to demonstrate that the new digital dental education device has considerable potential as a digital educational tool.

Effect of Position and Flow Waveform on the Fluid Mechanics of a Stenosed Human Right Coronary Artery

2001 ◽  
Author(s):  
K. B. Chandran ◽  
S. D. Ramaswamy ◽  
Y.-G. Lai ◽  
A. Wahle ◽  
M. Sonka
Keyword(s):  
Fluid Mechanics ◽  
Three Dimensional ◽  
Coronary Vessels ◽  
Mechanical Forces ◽  
Flow Waveform ◽  
Human Right ◽  
Plaque Growth ◽  
Oscillatory Shear Stress ◽  
The Relationship

Abstract Complete occlusion in any of the coronary vessels leads to a myocardial infarction. The role of fluid mechanical forces in atheroma development has been widely accepted because of preferential plaque growth at certain locations of the vessel geometry, such as a bifurcation or regions of high degrees of curvature. Areas of low and/or oscillatory shear stress have been correlated with atheroma development [1]. In order to determine the relationship between fluid mechanical stresses and development of lesions in the coronary vessels, it is important to analyze the fluid mechanics in actual three-dimensional geometries, incorporating the time-dependent translation and geometric alterations of these vessels [2,3].

A Method for Controlling Arrival Time to Prevent Late Arrival by Manipulating Vehicle Timetable Information

2020 ◽  
Vol 1 (1) ◽  
pp. 1-17
Author(s):  
Kyosuke Futami ◽  
Tsutomu Terada ◽  
Masahiko Tsukamoto
Keyword(s):  
Public Transportation ◽  
Psychological Factors ◽  
Arrival Time ◽  
Time Interval ◽  
Prototype System ◽  
Time Intervals ◽  
Target Vehicle ◽  
Late Arrival ◽  
Departure Time ◽  
The Relationship

Although it is socially and ethically important not to be late for a specified arrival time, late arrivals sometimes happen to people using public transportation. Although many methods aim to smooth a user's movement by providing useful information, there are few approaches to prevent late arrivals due to psychological factors. In this research, to make a user's arrival time earlier and thus prevent late arrival, we propose a method that manipulates time allowance by presenting information based on a psychological and cognitive tendency. We apply this method to a vehicle timetable system for the purpose of preventing public transit users from arriving after a target vehicle's departure time. Our proposed timetable system manipulates the time intervals between a user's target vehicle and other vehicles by introducing fictional elements such as hidden vehicles and inserted fictional vehicles. This method uses the relationship between the time allowance and the departure time interval, and it can make a user desire and accept arriving at a station earlier. We implemented a prototype system and conducted four experiments. The evaluation results confirmed that our proposed method is effective for changing a user's time allowance and actual arrival time.

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