Spatially and Temporally Resolved Temperature Measurements for Slow Evaporating Sessile Drops Heated by a Microfabricated Heater Array

2006 ◽  
Vol 129 (8) ◽  
pp. 966-976 ◽  
Author(s):  
S. W. Paik ◽  
K. D. Kihm ◽  
S. P. Lee ◽  
D. M. Pratt
Keyword(s):  
Contact Surface ◽  
Temperature Sensor ◽  
Water Droplet ◽  
Linear Array ◽  
Temperature History ◽  
Initial Contact ◽  
Constant Voltage ◽  
Radial Temperature ◽  
Spatially Resolved ◽  
History Of

The spatially and temporally resolved evaporation phenomena of a slowly evaporating water droplet are investigated using a microfabricated gold heater array consisting of 32 linear heater elements (100 μm wide and 15 mm long, each). Each of the gold microheater elements works both as a temperature sensor and as a heater. The experiment is performed under a constant voltage mode to examine the spatially resolved temperature history of the droplet contact surface for a period starting at initial contact with the heater and lasting to the point of complete dryout. The raw data obtained from the linear array have been tomographically deconvolved so that the radial temperature profile can be determined assuming a circular droplet contact surface.

A Three-Dimensional Finite Difference Solution for the Thermal Stresses in Railcar Wheels

1969 ◽  
Vol 91 (3) ◽  
pp. 891-896 ◽  
Author(s):  
G. E. Novak ◽  
B. J. Eck
Keyword(s):  
Computer Program ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Transient Temperature ◽  
Shear Stresses ◽  
Radial Temperature ◽  
Closed Form Solutions ◽  
Brake Application ◽  
History Of ◽  
Thin Disks

A numerical solution is presented for both the transient temperature and three-dimensional stress distribution in a railcar wheel resulting from a simulated emergency brake application. A computer program has been written for generating thermoelastic solutions applicable to wheels of arbitrary contour with temperature variations in both axial and radial directions. The results include the effect of shear stresses caused by the axial-radial temperature gradients and the high degree of boundary irregularity associated with this type of problem. The program has been validated by computing thermoelastic solutions for thin disks and long cylinders; the computed values being in good agreement with the closed form solutions. Currently, the computer program is being extended to general stress solutions corresponding to the transient temperature distributions obtained by simulated drag brake applications. When this work is completed, it will be possible to synthesize the thermal history of a railcar wheel and investigate the effects of wheel geometry in relation to thermal fatigue.

scholarly journals Spatially Resolved Stellar Populations and Kinematics with KCWI: Probing the Assembly History of the Massive Early-type Galaxy NGC 1407

2019 ◽  
Vol 878 (2) ◽  
pp. 129 ◽  
Author(s):  
Anna Ferré-Mateu ◽  
Duncan A. Forbes ◽  
Richard M. McDermid ◽  
Aaron J. Romanowsky ◽  
Jean P. Brodie
Keyword(s):  
Stellar Populations ◽  
Early Type ◽  
Spatially Resolved ◽  
History Of ◽  
Early Type Galaxy

Optimization of Laser Hardening Processes for Industrial Parts With Complex Geometry via Predictive Modeling

2009 ◽  
Author(s):  
Neil S. Bailey ◽  
Yung C. Shin
Keyword(s):  
Phase Transformation ◽  
Thermal Model ◽  
Complex Geometry ◽  
Solid Phase ◽  
Three Dimensional ◽  
Laser Hardening ◽  
Temperature History ◽  
Temperature Phase ◽  
Laser Systems ◽  
History Of

A predictive laser hardening model for industrial parts with complex geometric features has been developed and used for optimization of hardening processes. A transient three-dimensional thermal model is combined with a three-dimensional kinetic model for steel phase transformation and solved in order to predict the temperature history and solid phase history of the workpiece while considering latent heat of phase transformation. Further, back-tempering is also added to the model to determine the phase transformation during multitrack laser hardening. The integrated model is designed to accurately predict temperature, phase distributions and hardness inside complex geometric domains. The laser hardening parameters for two industrial workpieces are optimized for two different industrial laser systems using this model. Experimental results confirm the validity of predicted results.

Predicting strength of additively manufactured thermoplastic polymer parts produced using material extrusion

2018 ◽  
Vol 24 (2) ◽  
pp. 321-332 ◽  
Author(s):  
Joseph Bartolai ◽  
Timothy W. Simpson ◽  
Renxuan Xie
Keyword(s):  
Infrared Imaging ◽  
Acrylonitrile Butadiene Styrene ◽  
Temperature History ◽  
Interface Temperature ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Material Extrusion ◽  
Rheological Data ◽  
History Of ◽  
Butadiene Styrene

Purpose The weakest point in additively manufactured polymer parts produced by material extrusion additive manufacturing (MEAM) is the interface between adjacent layers and deposition toolpaths or “roads”. This study aims to predict the mechanical strength of parts by utilizing a novel analytical approach. Strength predictions are made using the temperature history of these interfaces, polymer rheological data, and polymer weld theory. Design/methodology/approach The approach is validated using experimental data for two common 3D-printed polymers: polycarbonate (PC) and acrylonitrile butadiene styrene (ABS). Interface temperature history data are collected in situ using infrared imaging. Rheological data of the polycarbonate and acrylonitrile butadiene styrene used to fabricate the fused filament fabrication parts in this study have been determined experimentally. Findings The strength of the interfaces has been predicted, to within 10% of experimental strength, using polymer weld theory from the literature adapted to the specific properties of the polycarbonate and acrylonitrile butadiene styrene feedstock used in this study. Originality/value This paper introduces a novel approach for predicting the strength of parts produced by MEAM based on the strength of interfaces using polymer weld theory, polymer rheology, temperature history of the interface and the forces applied to the interface. Unlike methods that require experimental strength data as a prediction input, the proposed approach is material and build orientation agnostic once fundamental parameters related to material composition have been determined.

scholarly journals On the Joint Interpretation of Total Gas Contents and Stable Isotope Ratios in Ice Cores

1982 ◽  
Vol 3 ◽  
pp. 152-155 ◽  
Author(s):  
D. Jenssen ◽  
U. Radok
Keyword(s):  
Ice Sheet ◽  
Ice Cores ◽  
Temperature History ◽  
Recent Analysis ◽  
Algebraic Expression ◽  
Linear Relationships ◽  
Ice Sheet Modeling ◽  
History Of ◽  
Joint Interpretation ◽  
Climatic History

Total gas contents of ice cores together with temperature estimates derived from 180/160 and 2D/1H values have been used to separate topographic and climatic changes in the deposition temperature history of the ice (Raynaud 1977, Jenssen 1978). The most recent analysis (Jenssen in press) made use of two linear relationships (one purely empirical, the other established empirically but subsequently justified theoretically) to derive an algebraic expression for the change of surface temperature with ice-sheet elevation. A physical line of reasoning is presented which instead infers the climatic history from changes in the surface topography of the ice sheet. This suggests that a complete interpretation of core data must go hand in hand with ice-sheet modeling.

An X-ray Diffraction Method for the Determination of Temperatures in Coke Reactions

1984 ◽  
Vol 28 ◽  
pp. 383-388 ◽  
Author(s):  
Jack L. Johnson ◽  
Seymour Katz
Keyword(s):  
Diffraction Method ◽  
Temperature History ◽  
Maximum Temperature ◽  
Slag Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Potential Source ◽  
History Of ◽  
Extract Information

Information about the conditions and reactions in a foundry cupola is essential to understand the thermochemistry of a cupola and thus improve its efficiency. A potential source of such information is coke taken from inside an operating cupola. In the region of the cupola that extends from the melt zone to the taphole, coke is directly involved in important chemical processes such as combustion, gasification, slag formation, iron sulfurization, carbon pickup, and oxide reduction. Coke is also suspected of being involved in the transport of silicon to the liquid iron. Each of these processes produces characteristic physical and/or chemical changes in the coke, making it possible to extract information about the processes from an examination of coke pieces taken from within an operating cupola. A program to study such coke samples is in progress. To effectively interpret these data it is necessary to know the temperature history of the coke being examined, especially the maximum temperature attained by the coke piece in the cupola.

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