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Full-Text Articles in Engineering

Lead-Free Interconnection For Electronic Devices, Ravi F. Saraf Dec 1998

Lead-Free Interconnection For Electronic Devices, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

An electronic device that is equipped with a plurality of bonding pads positioned on the device for making electrical interconnections and electrically conductive composite bumps adhered to the bonding pads wherein the bumps are formed of a composite material consisting of a thermoplastic polymer and at least about 30 volume percent of conductive metal particles based on the total volume of the metal particles and the thermoplastic polymer. The present invention is also directed to a method of making electrical interconnections to an electronic device by pressing a plurality of composite bumps of a polymeric based material against a substrate …


Optimization Of Temperature-Glycerol -Ph Conditions For Fed-Batch Fermentation Process For Recombinant Hookworm (Ancylostoma Caninurn) Anticoagulant Peptide (Acap-5) Production By Pichia Pastoris, Mehmet Inan, Vijay Chiruvolu, Kent M. Eskridge, George P. Vlasuk, Kenneth Dickerson, Scott Brown, Michael M. Meagher Dec 1998

Optimization Of Temperature-Glycerol -Ph Conditions For Fed-Batch Fermentation Process For Recombinant Hookworm (Ancylostoma Caninurn) Anticoagulant Peptide (Acap-5) Production By Pichia Pastoris, Mehmet Inan, Vijay Chiruvolu, Kent M. Eskridge, George P. Vlasuk, Kenneth Dickerson, Scott Brown, Michael M. Meagher

Papers in Biochemical Engineering

This study was undertaken to determine the optimum pH, temperature and glycerol feed rate for the production of recombinant hookworm (Ancylostoma caninum) anticoagulant peptide (rAcAP-5) by Pichia pastoris using response surface methodology (RSM). A central composite design was used as an experimental design for allocation of treatment combinations in three blocks. The variables selected for study were pH, temperature and glycerol feed rate. pH was the most important variable affecting yield, specific yield and specific activity of rAcAP-5. Glycerol feed rate had a significant effect on the specific activity of rAcAP-5 (% of total secreted protein) while temperature did not …


Entropy Generation In A Rectangular Packed Duct With Wall Heat Flux, Yaşar Demirel, Ramazan Kahraman Sep 1998

Entropy Generation In A Rectangular Packed Duct With Wall Heat Flux, Yaşar Demirel, Ramazan Kahraman

Papers in Thermal Mechanics

The entropy generation due to heat transfer and friction has been calculated for fully developed, forced convection flow in a large rectangular duct, packed with spherical particles, with constant heat fluxes applied to both the top (heated) and bottom (cooled) wall. An approximate analytical expression for the velocity profile developed for packed bed with H/dp > 5 has been used together with the energy equation of fully developed flow to calculate the non isothermal temperature profiles along the flow passage. The velocity profile takes into account the increase in the velocity near the wall due to the higher voidage in this …


Electronic Package Comprising A Substrate And A Semiconductor Device Bonded Thereto, Ravi F. Saraf Jul 1998

Electronic Package Comprising A Substrate And A Semiconductor Device Bonded Thereto, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A composition containing a polymeric matrix and a conductive filler component is provided. The conductive filler component comprises conductive particles and a polymer selected from the group consisting of substituted and unsubstituted polyanilines, substituted and unsubstituted polyparaphenylenevinylenes, substituted and unsubstituted polythiophenes, substituted and unsubstituted polyazines, substituted and unsubstituted polyparaphenylenes, substituted and unsubstituted polyfuranes, substituted and unsubstituted polypyrroles, substituted and unsubstituted polyselenophene, substituted and unsubstituted poly-p-phenylene sulfides and substituted and unsubstituted polyacetylenes, and mixtures thereof, and copolymers thereof. The compositions of the present invention are useful as adhesives for interconnecting a semiconductor chip to a substrate


Electronic Package Comprising A Substrate And A Semiconductor Device Bonded Thereto, Ravi F. Saraf Jul 1998

Electronic Package Comprising A Substrate And A Semiconductor Device Bonded Thereto, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A composition containing a polymeric matrix and a conductive filler component is provided. The conductive filler component comprises conductive particles and a polymer selected from the group consisting of substituted and unsubstituted polyanilines, substituted and unsubstituted polyparaphenylenevinylenes, substituted and unsubstituted polythiophenes, substituted and unsubstituted polyazines, substituted and unsubstituted polyparaphenylenes, substituted and unsubstituted polyfuranes, substituted and unsubstituted polypyrroles, substituted and unsubstituted polyselenophene, substituted and unsubstituted poly-p-phenylene sulfides and substituted and unsubstituted polyacetylenes, and mixtures thereof, and copolymers thereof. The compositions of the present invention are useful as adhesives for interconnecting a semiconductor chip to a substrate


Direct Chip Attachment (Dca) With Electrically Conductive Adhesives, Ravi F. Saraf May 1998

Direct Chip Attachment (Dca) With Electrically Conductive Adhesives, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A simple process for card assembly by Direct Chip Attachment (DCA) uses electrically conductive adhesives. Two methods create the same intermediate wafer product with a layer of insulative thermoplastic and conductive thermoplastic bumps. After sawing or dicing the wafer to form the chips, the chips are adhered to chip carriers with conductive pads which match the conductive thermoplastic bumps, using heat and pressure. Chips may be easily removed and replaced using heat.


Direct Chip Attachment (Dca) With Electrically Conductive Adhesives, Ravi F. Saraf May 1998

Direct Chip Attachment (Dca) With Electrically Conductive Adhesives, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A simple process for card assembly by Direct Chip Attachment (DCA) uses electrically conductive adhesives. Two methods create the same intermediate wafer product with a layer of insulative thermoplastic and conductive thermoplastic bumps. After sawing or dicing the wafer to form the chips, the chips are adhered to chip carriers with conductive pads which match the conductive thermoplastic bumps, using heat and pressure. Chips may be easily removed and replaced using heat.


Direct Chip Attachment (Dca) With Electrically Conductive Adhesives, Ravi F. Saraf May 1998

Direct Chip Attachment (Dca) With Electrically Conductive Adhesives, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A simple process for card assembly by Direct Chip Attachment (DCA) uses electrically conductive adhesives. Two methods create the same intermediate wafer product with a layer of insulative thermoplastic and conductive thermoplastic bumps. After sawing or dicing the wafer to form the chips, the chips are adhered to chip carriers with conductive pads which match the conductive thermoplastic bumps, using heat and pressure. Chips may be easily removed and replaced using heat.


Analysis Of Combustion-Driven Acoustics, L Boshoff-Mostert, Hendrik J. Viljoen May 1998

Analysis Of Combustion-Driven Acoustics, L Boshoff-Mostert, Hendrik J. Viljoen

Papers in Reaction Kinetics

Abstract-Combustion-driven acoustic oscillations are investigated by performing a onedimensional stability analysis of a burner-stabilized premixed flame. In contrast to other investigators, no initial acoustic wave is assumed in the analysis; the downstream acoustic field results from flame instability. Two models are considered: the thermodiffusive model (uncoupled model) and the fully coupled thermodiffusive-hydrodynamic model. The fully coupled problem exhibits instability at a much lower critical Lewis number than the uncoupled problem.


A Study Of Piezoelectric Orthorhombic Ta2O5, B. R. Jooste, Hendrik J. Viljoen Feb 1998

A Study Of Piezoelectric Orthorhombic Ta2O5, B. R. Jooste, Hendrik J. Viljoen

Hendrik J. Viljoen Publications

In 1985 it was first reported that monoclinic Ta2O5 has piezoelectric properties comparable to ZnO. In this work we report on the deposition, characterization, and qualitative assessment of the piezoelectric behavior of orthorhombic Ta2O5. Reactive magnetron sputtering was used to deposit thin films of Ta2O5 onto substrates of 316L stainless steel. Without substrate heating the crystallinity was poor. A rapid thermal anneal improved the crystallinity. The orthorhombic phase was dominantly present on all substrates. The piezoelectric property was qualitatively assessed, including a high temperature test at 650 °C.