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Dive into the research topics where E. E. Marotta is active.

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Featured researches published by E. E. Marotta.


Journal of Thermophysics and Heat Transfer | 1996

Thermal contact conductance of selected polymeric materials

E. E. Marotta; L. S. Fletcher

The thermal conductivity and thermal contact conductance of several thermoplastic and thermosetting polymers have been studied over a range of interface pressures and temperatures. The temperature range for the thermal conductivity study varied from 10 to 100°C (50 to 212°F). The study showed that ultra high molecular weight (UHMW) polyethylene had the highest thermal conductivity through the range of temperatures and also had the highest thermal conductance values at an interface temperature of 20°C (68°F). The thermal contact conductance study was conducted over a pressure range of 510-2760 kPa (75-400 psi) and a temperature range of 20-40°C (68-104°F). The conductance values for UHMW polyethylene ranged from 1095.3 to 1659.4 W/m2 K (192.9 to 292.2 Btu/h ft2 °F), whereas the thermal conductivity remained constant at 0.45 W/m K (0.26 Btu/h ft °F) throughout the range of temperatures. Polycarbonate and Teflon® had the next highest thermal conductance values at the same interface temperature. The thermal contact conductance values for polyethylene, Teflon, and phenolic polymers were measured at an elevated temperature of 40°C (104°F). The thermal contact conductance values for both Teflon and phenolic increased with increasing temperature, whereas the values for UHMW polyethylene decreased due to their unique chain structure at the higher temperature. The polymers were chosen because of their widespread engineering interest applications.


Journal of Thermophysics and Heat Transfer | 2001

Thermal Contact Conductance of Metal/Polymer Joints: An Analytical and Experimental Investigation

J. J. Fuller; E. E. Marotta

The heat e ow across a metal/polymer interface is a very important problem in many modern engineering applications. A thermal joint conductance model that employs the surface mechanics of a contact interface in conjunction with an existing elastic thermal contact conductance model was developed. In developing the model, an elastic contact hardness term was derived to predict the actual contact area of a metal/polymer interface under loading. The model predicts a microscopic resistance region where the interface resistance is dominant and a bulk resistance region where the thermal conductivity of the polymer is dominant. An experimental apparatus was fabricated, and a successful experimental program was conducted. New experimental data were gathered on different polymeric specimens over a pressure range of 138 ‐2758 kPa (20‐400 psi). The experimental data were compared to the proposed thermal joint conductance model. It was found that the proposed model predicted the data quite well. The data followed the predicted trends for both the microscopic and bulk resistance regions.


Journal of Thermophysics and Heat Transfer | 1997

Thermal Contact Conductance of Adhesives for Microelectronic Systems

S. R. Mirmira; E. E. Marotta; L. S. Fletcher

Adhesives, which are often used to attach a silicon device to a heat spreader or ceramic substrate, generally increase the heat transfer across the material junction and improve the thermal contact conductance. This investigation evaluated the effect of RTV and epoxy adhesives and high-temperature cements on the thermal contact conductance between aluminum 6106-T6 and aluminum 356-T61. The thermal contact conductance was evaluated at mean interface temperatures of 25 and 60°C (77 and 140°F) and at pressures ranging from 345 to 2756 kPa (50 to 400 psi). The thermal contact conductance values of these adhesives were not significantly affected by variations in specified interface temperature or pressure, however, adhesive thickness and thermal conductivity were influential in the measured conductance.


Journal of Thermophysics and Heat Transfer | 1998

Thermal Contact Conductance for Aluminum and Stainless-Steel Contacts

E. E. Marotta; L. S. Fletcher

In the present study, existing analytical models developed to predict the thermal contact conductance for both aluminum/aluminum and aluminum/stainless steel surfaces in contact have been evaluated. The prediction of thermal contact conductance for these contacting pairs is difficult since a thin native oxide film generally occurs naturally on the aluminum materials. Therefore, one of the objectives of this study was to determine whether elastic or plastic thermal contact models could successfully predict both published and present experimental data for these commercially important alloys. A rigorous analytical analysis was conducted to check the validity of existing models (assuming either elastic or plastic deformation a priori) to predict the thermal contact conductance for nominally flat uncoated aluminum surfaces in contact under vacuum conditions. Both elastic and plastic deformation models were compared with new unpublished experimental data for nominally flat, roughened surfaces. NOMENCLATURE A Fraction of area in real contact Aa Apparent area a Contact spot radius (m) BJH Microscopic gap number b Flux tube radius (m) Cjn Microscopic constriction number E Youngs Modulus (N/m2)


Journal of Electronic Packaging | 1998

Thermal Enhancement Coatings for Microelectronic Systems

L. S. Fletcher; M. A. Lambert; E. E. Marotta

The power densities and heat generation in microelectronic systems have increased dramatically as individual electronic components have been miniaturized. As a result of the growing number of thermally-induced failures in these systems, their thermal performance has become the focus of increasing concern. The use of thermally conducting interstitial coatings within and between electronic components has proven to be one technique suitable for thermal enhancement. This review will address both metallic and non-metallic coatings suitable for thermal enhancement and discuss some of the major areas of application.


ASME 2004 International Mechanical Engineering Congress and Exposition | 2004

Modeling of Thermal Joint Resistance of Polymer-Metal Rough Interfaces

Majid Bahrami; M. M. Yovanovich; E. E. Marotta

A compact analytical model is developed for predicting thermal joint resistance of rough polymer-metal interfaces in a vacuum. The joint resistance includes two components: i) bulk resistance of the polymer and ii) micro, constriction/spreading resistance of the microcontacts at the interface. Performing a deformation analysis, it is shown that the deformation mode of the polymer asperities is plastic. The required input parameters of the model can be measured in the laboratory and/or found in the open literature. It is observed that the thermophysical properties of the polymer control the thermal joint resistance and the metallic body properties have a second order effect on the thermal joint resistance. A non-dimensional parameter, i.e., ratio of microcontacts over bulk thermal resistances, is proposed as a criterion to specify the relative importance of the microcontacts thermal resistance. The present model is compared with more than 140 experimental data points collected for a selected number of polymers and showed good agreement.


Journal of Thermophysics and Heat Transfer | 1999

Thermal Contact Conductance of Metal/Polymer Joints

J. J. Fuller; E. E. Marotta


35th Aerospace Sciences Meeting and Exhibit | 1997

Thermal contact conductance of elastomeric gaskets

S. R. Mirmira; E. E. Marotta; L. S. Fletcher


AIAA Aerospace Sciences Meeting and Exhibit | 1996

Thermal contact conductance of diamond-like films

E. E. Marotta; D. G. Blanchard; L. S. Fletcher


33rd Aerospace Sciences Meeting and Exhibit | 1995

Thermal contact conductance of polymeric materials

E. E. Marotta; L. S. Fletcher

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