Use of Simulated Thermal Cues for Material Discrimination and Identification with a Multi-Fingered Display

2008 ◽  
Vol 17 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Gi-Hun Yang ◽  
Lynette A. Jones ◽  
Dong-Soo Kwon
Keyword(s):  
Thermal Properties ◽  
Virtual Environments ◽  
Thermal Contact ◽  
Spatial Summation ◽  
Blood Perfusion ◽  
Infinite Body ◽  
Real Material ◽  
Present Information ◽  
Material Discrimination ◽  
Simulated Material

Thermal cues provide information about the thermal properties of an object held in the hand. These cues can be simulated in a thermal display and used to assist in identifying the object. Two experiments were conducted using a thermal display that simulated the cues associated with contact with different materials. The thermal contact model was based on a semi-infinite body model that included thermal contact resistance and blood perfusion. Its performance was evaluated in two experiments, the first of which involved discriminating between simulated materials, and in the second, subjects were required to identify simulated materials based on the thermal cues presented to one, three, or five fingers. The results from the first experiment indicated that when the temperature profile associated with contact with a real material is presented to the finger, subjects can use this cue to discriminate between simulated materials. Their performance on this task is comparable to that achieved with real materials with similar thermal properties. In the second experiment, the accuracy with which subjects identified a simulated material based on thermal cues improved as the number of fingers stimulated increased, suggesting that spatial summation of cold occurs when the area stimulated is noncontiguous. However, most of the improvement in identifying materials occurred when the display presented thermal cues to three as compared to one finger, with little further enhancement in performance when five fingers were stimulated. These results indicate that thermal displays can be used effectively to present information about the material composition of objects in virtual environments.

scholarly journals Scanning Thermal Microscopy of Ultrathin Films: Numerical Studies Regarding Cantilever Displacement, Thermal Contact Areas, Heat Fluxes, and Heat Distribution

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 491
Author(s):  
Christoph Metzke ◽  
Fabian Kühnel ◽  
Jonas Weber ◽  
Günther Benstetter
Keyword(s):  
Thermal Properties ◽  
Ultrathin Films ◽  
Hexagonal Boron Nitride ◽  
Thermal Contact ◽  
Heat Transfer Process ◽  
Heat Propagation ◽  
Heat Fluxes ◽  
Detailed Knowledge ◽  
Scanning Thermal Microscopy ◽  
Thermal Microscopy

New micro- and nanoscale devices require electrically isolating materials with specific thermal properties. One option to characterize these thermal properties is the atomic force microscopy (AFM)-based scanning thermal microscopy (SThM) technique. It enables qualitative mapping of local thermal conductivities of ultrathin films. To fully understand and correctly interpret the results of practical SThM measurements, it is essential to have detailed knowledge about the heat transfer process between the probe and the sample. However, little can be found in the literature so far. Therefore, this work focuses on theoretical SThM studies of ultrathin films with anisotropic thermal properties such as hexagonal boron nitride (h-BN) and compares the results with a bulk silicon (Si) sample. Energy fluxes from the probe to the sample between 0.6 µW and 126.8 µW are found for different cases with a tip radius of approximately 300 nm. A present thermal interface resistance (TIR) between bulk Si and ultrathin h-BN on top can fully suppress a further heat penetration. The time until heat propagation within the sample is stationary is found to be below 1 µs, which may justify higher tip velocities in practical SThM investigations of up to 20 µms−1. It is also demonstrated that there is almost no influence of convection and radiation, whereas a possible TIR between probe and sample must be considered.

scholarly journals Multi-Layer Transient Heat Conduction Involving Perfectly-Conducting Solids

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6484
Author(s):  
Giampaolo D’Alessandro ◽  
Filippo de Monte
Keyword(s):  
Heat Conduction ◽  
Thin Layer ◽  
Layer Structure ◽  
Thermal Contact ◽  
Internal Heat ◽  
Transient Heat Conduction ◽  
Back Side ◽  
Infinite Body ◽  
Imperfect Contact ◽  
Finite Body

Boundary conditions of high kinds (fourth and sixth kind) as defined by Carslaw and Jaeger are used in this work to model the thermal behavior of perfect conductors when involved in multi-layer transient heat conduction problems. In detail, two- and three-layer configurations are analyzed. In the former, a thin layer modeled as a lumped body is subject to a surface heat flux on the front side while it is in perfect (fourth kind) or in imperfect (sixth kind) thermal contact with a semi-infinite or finite body on the back side. When dealing with a semi-infinite body in imperfect contact, the temperature solution is derived by means of the Laplace transform method. Green’s function approach is also used but for solving the companion case of a finite body in perfect contact with the thin film. In the latter, a thin layer with internal heat generation is located between two semi-infinite or finite bodies in perfect/imperfect contact. For the sake of thermal symmetry, such a three-layer structure reduces to a two-layer configuration. Results are given in both tabular and graphical forms and show the effect of heat capacity and thermal resistance on the temperature distribution of conductive layers.

A COMPREHENSIVE TISSUE PROPERTIES DATABASE PROVIDED FOR THE THERMAL ASSESSMENT OF A HUMAN AT REST

2010 ◽  
Vol 05 (03) ◽  
pp. 129-151 ◽  
Author(s):  
ROBERT L. MCINTOSH ◽  
VITAS ANDERSON
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Thermal Modeling ◽  
Blood Perfusion ◽  
Human Tissues ◽  
Tissue Properties ◽  
Future Studies ◽  
Average Value ◽  
Metabolic Heat

Accurate numerical calculation of the thermal profile in humans requires reliable estimates of the following five tissue properties: specific heat capacity (c), thermal conductivity (k), blood perfusion rates (m), metabolic heat production (A0), and density (ρ). A sixth property, water content (w, as a %), can also be used to estimate c and k. To date, researchers have used various and inconsistent estimates of these parameters, which hinders comparison of the corresponding results. In an effort to standardize and improve the accuracy of these parameters for future studies, we have documented over 150 key papers and books and developed a database of the six thermal properties listed above for 43 human tissues. For each tissue and each property the following were obtained: the average value, the number of source values, the minimum and maximum of source values, and the reference for each source value. A key premise for the development of the database was to only use references that provided the original measurements. This database is offered for use by the biological thermal modeling community to help improve the accuracy and consistency of thermal modeling results.

Thermal Properties of Thin Metallic Layer Deposited on Insulators: Effect of the Interface on the Independent Determination of the Thermal Diffusivity and Conductivity of the Layer

2008 ◽  
Author(s):  
Danie`le Fournier ◽  
Jean Paul Roger ◽  
Christian Fretigny
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Thermal Resistance ◽  
Thermal Contact ◽  
Heat Diffusion ◽  
Metallic Layer ◽  
Good Thermal Contact ◽  
Lateral Heat

Lateral heat diffusion thermoreflectance is a very powerful tool for determining directly the thermal diffusivity of layered structures. To do that, experimental data are fitted with the help of a heat diffusion model in which the ratio between the thermal conductivity k and the thermal diffusivity D of each layer is fixed, and the thermal properties of the substrate are known. We have shown in a previous work that it is possible to determine independently the thermal diffusivity and the thermal conductivity of a metallic layer deposited on an insulator, by taking into consideration all the data obtained at different modulation frequencies. Moreover, it is well known that to prevent a lack of adhesion of a gold film deposited on substrates like silica, an intermediate very thin (Cr or Ti) layer is deposited to assure a good thermal contact. We extend our previous work: the asymptotic behaviour determination of the surface temperature wave at large distances from the modulated point heat source for one layer deposited on the substrate to the two layers model. In this case (very thin adhesion coating whose thermal properties and thickness are known), it can be establish that the thermal diffusivity and the thermal conductivity of the top layer can still be determined independently. It is interesting to underline that the calculus can also be extended to the case of a thermal contact resistance which has often to be taken into account between two solids. We call thermal resistance a very thin layer exhibiting a very low thermal conductivity. In this case, the three parameters we have to determine are the thermal conductivity and the thermal diffusivity of the layer and the thermal resistance. We will show that, in this case, the thermal conductivity of the layer is always obtained independently of a bound of the couple thermal resistance – thermal diffusivity, the thermal diffusivity being under bounded and the thermal resistance lower bounded. Experimental results on thin gold layers deposited on silica with and without adhesion layers are presented to illustrate the method. Discussions on the accuracy will also be presented.

Visual cues enhance user performance in virtual environments

2018 ◽  
Vol 46 (1) ◽  
pp. 11-24 ◽  
Author(s):  
Yongsuk Hwang ◽  
Donghee Shin
Keyword(s):  
Cognitive Load ◽  
Virtual Environments ◽  
Learning Outcomes ◽  
Visual Cues ◽  
Design Strategy ◽  
User Performance ◽  
3 Dimensional ◽  
Visual Cueing ◽  
Present Information ◽  
Static Images

We examined the effects of visual cueing in an effort to identify the optimal way to present information in a 3-dimensional (3D) virtual environment. To strategically compensate for the lack of permanency, we combined dynamic and static visualizations into 1 medium by adding transparent static images (visual cueing) to an animation. A between-subjects experiment (N = 100) was conducted to examine the effects of visual cueing on cognitive load and learning outcomes. Results showed that combining dynamic and static visualizations was beneficial for reducing cognitive load, although it did not improve learning outcomes. On the basis of our findings, we suggest a design strategy for improving the effectiveness of 3D instructional animations that is broadly applicable to numerous learning contexts, such as virtual or augmented reality.

scholarly journals Thermal contact resistance across a linear heterojunction within a hybrid graphene/hexagonal boron nitride sheet

2016 ◽  
Vol 18 (35) ◽  
pp. 24164-24170 ◽  
Author(s):  
Yang Hong ◽  
Jingchao Zhang ◽  
Xiao Cheng Zeng
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Boron Nitride ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Hexagonal Boron Nitride ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Vital Role ◽  
Interfacial Thermal Conductance

Interfacial thermal conductance plays a vital role in defining the thermal properties of nanostructured materials in which heat transfer is predominantly phonon mediated.

scholarly journals Effect of Heat Source and Imperfect Contact on Simultaneous Estimation of Thermal Properties of High-Conductivity Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Giampaolo D’Alessandro ◽  
Filippo de Monte ◽  
Donald E. Amos
Keyword(s):  
Heat Capacity ◽  
Thermal Properties ◽  
Heated Surface ◽  
Thermal Contact ◽  
High Conductivity ◽  
Simultaneous Estimation ◽  
Transform Method ◽  
Imperfect Contact ◽  
Experimental Apparatus ◽  
Layer Sample

In the current paper a novel methodology accounting for both the heater heat capacity and the imperfect thermal contact between a thin heater and a specimen is proposed. In particular, the volumetric heat capacity of the heater is considered by modelling it as a lumped capacitance body, while the imperfect thermal contact is considered by means of a contact resistance. Thus, the experimental apparatus consisting of three layers (specimen-heater-specimen) is reduced to a single finite layer (sample) subject to a “nonclassical” boundary condition at the heated surface, known as sixth kind. Once the temperature solution is derived analytically using the Laplace transform method, the scaled sensitivity coefficients are computed analytically at the interface between the heater and the sample (heater side and sample side) and at the sample backside. By applying the proposed methodology to a lab-controlled experiment available in the specialized literature, a reduction of the thermal properties values of about 1.4% is observed for a high-conductivity material (Armco iron).

Numerical Determination of Thermal Contact Resistance for Nonisothermal Forging Processes

2000 ◽  
Vol 122 (4) ◽  
pp. 776-784 ◽  
Author(s):  
A.-S. Marchand ◽  
M. Raynaud
Keyword(s):  
Thermal Properties ◽  
Finite Difference Method ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Numerical Study ◽  
Thermal Contact ◽  
Numerical Determination ◽  
Predictive Capability ◽  
Interface Geometry

A numerical study is conducted to estimate the thermal contact resistance (TCR) between the tool and the workpiece during slow nonisothermal forging processes. A finite difference method is used to determine the TCR from a thermomechanical microscopic model. Correlations of the numerical results are developed for the TCR as a function of the interface geometry and the thermal properties. The method used to introduce these correlations in forging softwares, to account for a time and space-dependent TCR instead of a constant arbitrary value, is given. The predictive capability of the correlations is partially validated by comparing their outputs with TCR results from the literature. [S0022-1481(00)00903-8]

Temperature Profiles During Cryolipolysis

2021 ◽  
Author(s):  
Dillon McClintock ◽  
Neil T. Wright
Keyword(s):  
Adipose Tissue ◽  
Characteristic Length ◽  
Thermal Contact ◽  
Blood Perfusion ◽  
Clinical Procedure ◽  
Good Thermal Contact ◽  
Local Reduction ◽  
Pennes Equation ◽  
Two Parameters ◽  
Subcutaneous Adipose

Abstract Cryolipolysis is a noninvasive clinical procedure for the local reduction of adipose tissue. Paddles as cold as ~10 °C are placed in good thermal contact the epidermis. The goal is to cool the subcutaneous adipose tissue to ~10 °C, which induces apoptosis and an inflammatory response in the adipocytes. The dermis is, of course, cooler than the adipocytes, but the triglyceride in the adipocytes are thought to crystalize, causing apoptosis. The clinical procedure have been developed empirically. A mathematical model could aid in understanding the mechanisms of response and improving the design of the procedure. Here, the Pennes equation is used to model the temperature of the tissue during cooling. The two parameters identified are the thermal diffusivity of the tissue and a blood perfusion parameter, which also gives the characteristic length. Green's functions are used to solve the Pennes equation, which simplifies to a transient fin equation.

scholarly journals Noninvasive Blood Perfusion Measurements of an Isolated Rat Liver and an Anesthetized Rat Kidney

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Ashvinikumar V. Mudaliar ◽  
Brent E. Ellis ◽  
Patricia L. Ricketts ◽  
Otto I. Lanz ◽  
Charles Y. Lee ◽  
...  
Keyword(s):  
Renal Artery ◽  
Rat Liver ◽  
Rat Kidney ◽  
Thermal Contact ◽  
Blood Perfusion ◽  
Cost Effective ◽  
Perfusion System ◽  
Isolated Rat Liver ◽  
Liver Tests ◽  
Isolated Rat

A simple, cost effective, and noninvasive blood perfusion system is tested in animal models. The system uses a small sensor to measure the heat transfer response to a thermal event (convective cooling) imposed on the tissue surface. Heat flux data are compared with a mathematical model of the tissue to estimate both blood perfusion and thermal contact resistance between the tissue and the probe. The perfusion system was evaluated for repeatability and sensitivity using isolated rat liver and exposed rat kidney tests. Perfusion in the isolated liver tests was varied by controlling the flow of the perfusate into the liver, and the perfusion in the exposed kidney tests was varied by temporarily occluding blood flow through the renal artery and vein. The perfusion estimated by the convective perfusion probe was in good agreement with that of the metered flow of the perfusate into the liver model. The liver tests indicated that the probe can be used to detect small changes in perfusion (0.005 ml/ml/s). The probe qualitatively tracked the changes in the perfusion in the kidney model due to occlusion of the renal artery and vein.

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