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Full-Text Articles in Engineering

Fast Super-Resolution With Affine Motion Using An Adaptive Wiener Filter And Its Application To Airborne Imaging, Russell C. Hardie, Kenneth J. Barnard, Raúl Ordóñez May 2015

Fast Super-Resolution With Affine Motion Using An Adaptive Wiener Filter And Its Application To Airborne Imaging, Russell C. Hardie, Kenneth J. Barnard, Raúl Ordóñez

Raúl Ordóñez

Fast nonuniform interpolation based super-resolution (SR) has traditionally been limited to applications with translational interframe motion. This is in part because such methods are based on an underlying assumption that the warping and blurring components in the observation model commute. For translational motion this is the case, but it is not true in general. This presents a problem for applications such as airborne imaging where translation may be insufficient. Here we present a new Fourier domain analysis to show that, for many image systems, an affine warping model with limited zoom and shear approximately commutes with the point spread function …


Impact Of Engineering Ambassador Programs On Student Development, Thalia Anagnos, Alicia Lyman-Holt, Claudia Marin-Artieda, Ellen Momsen Jan 2014

Impact Of Engineering Ambassador Programs On Student Development, Thalia Anagnos, Alicia Lyman-Holt, Claudia Marin-Artieda, Ellen Momsen

Thalia Anagnos

This study highlights the positive impact of participation in an engineering ambassador program on students from two universities: Oregon State University which is a large public university in a college town with a 13% minority student body, and Howard University, a medium sized private university with a relatively small engineering program in an urban setting enrolling a primarily minority population. Although these ambassador programs have a major goal of service to the university and engineering program, they serve an equally important goal of developing the skills and attitudes of the ambassadors themselves. Ambassadors from both universities were surveyed, and though …


An Interactive Exploration Of Gender And Engineering: Unpacking The Experience, Debbie Chachra, Lynn Stein, Alisha Sarang-Sieminski, Caitrin Lynch, Yevgeniya Zastavker Sep 2013

An Interactive Exploration Of Gender And Engineering: Unpacking The Experience, Debbie Chachra, Lynn Stein, Alisha Sarang-Sieminski, Caitrin Lynch, Yevgeniya Zastavker

Alisha L. Sarang-Sieminski

The engineering student experience is understood to differ for male and female students; gendered interactions affect the development of academic and professional role confidence, as well as engineering identity. The purpose of this session is twofold. First, we aim to introduce participants to concepts of gender schemas, privilege, and identity using a range of interactive activities, including brainstorming and structured discussion. Second, we intend to share information about and obtain feedback on a Gender Discussion Exploration Kit, which the participants will be encouraged to review, use, and share at their home institutions.


Developing A Small-Footprint Bioengineering Program, Alisha Sarang-Sieminski, Debbie Chachra Sep 2013

Developing A Small-Footprint Bioengineering Program, Alisha Sarang-Sieminski, Debbie Chachra

Alisha L. Sarang-Sieminski

The field of bioengineering is rapidly changing and expanding to include not only more traditional bioengineering applications (e.g. device-focused areas such as prosthetics, imaging) but also more recent sub-fields and technologies(e.g. more biologically-focused areas such as those enabled by tissue engineering and microfluidics). This rapid change, coupled with the intrinsically interdisciplinary nature of bioengineering, presents a unique challenge to the developers of academic programs, as they need to both select relevant content and strike a balance between depth and breadth. We, the architects of the bioengineering program at the undergraduate-only Franklin W. Olin College of Engineering, which enrolled its first …


Parallel Recording Of Neurotransmitters Release From Chromaffin Cells Using A 10 X 10 Cmos Ic Potentiostat Array With On-Chip Working Electrodes, Brian Kim, Adam Herbst, Sung Kim, Bradley Minch, Manfred Lindau Feb 2013

Parallel Recording Of Neurotransmitters Release From Chromaffin Cells Using A 10 X 10 Cmos Ic Potentiostat Array With On-Chip Working Electrodes, Brian Kim, Adam Herbst, Sung Kim, Bradley Minch, Manfred Lindau

Bradley Minch

Neurotransmitter release is modulated by many drugs and molecular manipulations. We present an active CMOS-based electrochemical biosensor array with high throughput capability (100 electrodes) for on-chip amperometric measurement of neurotransmitter release. The high-throughput of the biosensor array will accelerate the data collection needed to determine statistical significance of changes produced under varying conditions, from several weeks to a few hours. The biosensor is designed and fabricated using a combination of CMOS integrated circuit (IC) technology and a photolithography process to incorporate platinum working electrodes on-chip. We demonstrate the operation of an electrode array with integrated high-gain potentiostats and output time-division …


Settling And Bioflocculation Of Two Species Of Algae Used In Wastewater Treatment And Algae Biomass Production, Derek Manheim, Yarrow M. Nelson Jan 2013

Settling And Bioflocculation Of Two Species Of Algae Used In Wastewater Treatment And Algae Biomass Production, Derek Manheim, Yarrow M. Nelson

Yarrow Nelson

The settling and bioflocculation of two strains of algae were investigated in the laboratory to provide insights to help improve algae settling in large-scale, algae-based wastewater treatment systems with simultaneous algae biofuel production. Energyefficient algae harvesting is a requirement for cost effective production of biofuels from algae, but algae harvesting usually requires energy-intensive methods such as centrifugation, filtration or dissolved air flotation. Bioflocculation using bacteriallyderived exudates is promising, but its use in high-rate algae pond (HRAP) wastewater systems has not yielded consistently reliable settling. To improve our understanding of the complex interactions between mixed cultures of algae and bacteria, the …


Spectral-Efficiency Of Multi-Antenna Links In Ad-Hoc Networks With Limited Tx Csi, Siddhartan Govindasamy, Daniel Bliss, David Staelin Dec 2012

Spectral-Efficiency Of Multi-Antenna Links In Ad-Hoc Networks With Limited Tx Csi, Siddhartan Govindasamy, Daniel Bliss, David Staelin

Siddhartan Govindasamy

An asymptotic expression is derived for the mean spectral efficiency of multi-antenna links randomly distributed on a plane in a uniform manner where transmitters (Tx) have Channel-State-Information (CSI) of the channels between themselves and their target receivers while receivers (Rx) have CSI between themselves and all transmitters. The mean per-link spectral efficiency in the network is found to increase if nodes transmit using a subset of their strongest channel modes instead of the link-optimal strategy of water-filling on all channel modes (Farrokhi et al.). For reasonable parameters, this system which requires limited Tx CSI, has approximately double the mean spectral …


Spectral Efficiency In Single-Hop Ad-Hoc Wireless Networks With Interference Using Adaptive Antenna Arrays, Siddhartan Govindasamy, Daniel Bliss, David Staelin Dec 2012

Spectral Efficiency In Single-Hop Ad-Hoc Wireless Networks With Interference Using Adaptive Antenna Arrays, Siddhartan Govindasamy, Daniel Bliss, David Staelin

Siddhartan Govindasamy

Receivers with N antennas in single-hop, ad-hoc wireless networks with nodes randomly distributed on an infinite plane with uniform area density are studied. Transmitting nodes have single antennas and transmit simultaneously in the same frequency band with power P that decays with distance via the commonly-used inverse-polynomial model with path-loss-exponent (PLE) greater than 2. This model applies to shared spectrum systems where multiple links share the same frequency band. In the interference-limited regime, the average spectral efficiency of a representative link E[C] (b/s/Hz/link) is found to grow as log(N) and linearly with PLE, and its variance decays as 1/N. The …


Cdf Of The Spectral-Efficiency Of A Simple Distributed Channel Assignment Algorithm In Spatially Distributed Wireless Networks, Siddhartan Govindasamy, Raghu Rangan, Elena Koukina, Ashley Lloyd Dec 2012

Cdf Of The Spectral-Efficiency Of A Simple Distributed Channel Assignment Algorithm In Spatially Distributed Wireless Networks, Siddhartan Govindasamy, Raghu Rangan, Elena Koukina, Ashley Lloyd

Siddhartan Govindasamy

The Cumulative-Distribution-Function (CDF) of the spectral efficiency of links in spatially distributed networks with orthogonal channels and a simple channel assignment algorithm is presented for constant link-lengths and nearest-neighbor links. Transmitters are randomly distributed on the plane with uniform probability, and receivers are either randomly distributed or at hexagonal lattice sites. This result includes random channel assignments as a special case. The CDF is used to find the spectral efficiency for a given, small outage probability which is used to optimize the number of channels to maximize the spectral efficiency. The optimum number of channels represents the best trade off …


On The Spectral Efficiency Of Links With Multi-Antenna Receivers In Non-Homogenous Wireless Networks, Siddhartan Govindasamy, Daniel Bliss Dec 2012

On The Spectral Efficiency Of Links With Multi-Antenna Receivers In Non-Homogenous Wireless Networks, Siddhartan Govindasamy, Daniel Bliss

Siddhartan Govindasamy

An asymptotic technique is developed to find the Signal-to-Interference-plus-Noise-Ratio (SINR) and spectral efficiency of a link with N receiver antennas in wireless networks with non-homogeneous distributions of nodes. It is found that with appropriate normalization, the SINR and spectral efficiency converge with probability 1 to asymptotic limits as N increases. This technique is applied to networks with power-law node intensities, which includes homogeneous networks as a special case, to find a simple approximation for the spectral efficiency. It is found that for receivers in dense clusters, the SINR grows with N at rates higher than that of homogeneous networks and …


The Performance Of Linear Multiple-Antenna Receivers With Interferes Distributed On A Plane, Siddhartan Govindasamy, Filip Antic, Daniel Bliss, David Staelin Dec 2012

The Performance Of Linear Multiple-Antenna Receivers With Interferes Distributed On A Plane, Siddhartan Govindasamy, Filip Antic, Daniel Bliss, David Staelin

Siddhartan Govindasamy

We find an asymptotic expression for the average signal to interference ratio (SIR) between a transmitter with a single isotropic antenna and a multi-antenna linear receiver in the presence of interferers with single isotropic transmit antennas distributed uniformly on an infinite plane. The channels are modeled as complex Gaussian random variables with average received power dependent on the distance separating nodes. We find that in large networks, the average SIR for a representative link depends primarily on the ratio of the number of receive antenna elements to the area density of interferers. Furthermore for our network model, the SIR grows …


Minimizing Hidden-Node Network Interference By Optimizing Siso And Mimo Spectral Efficiency, Daniel Bliss, Siddhartan Govindasamy Dec 2012

Minimizing Hidden-Node Network Interference By Optimizing Siso And Mimo Spectral Efficiency, Daniel Bliss, Siddhartan Govindasamy

Siddhartan Govindasamy

In this paper, the optimal spectral efficiency (data rate divided by the message bandwidth) that minimizes the probability of causing disruptive interference for ad hoc wireless networks or cognitive radios is investigated. Two basic problem constraints are considered: a given message size, or fixed data rate. Implicitly, the trade being optimized is between longer transmit duration and wider bandwidth versus higher transmit power. Both single-input single-output (SISO) and multiple-input multiple-output (MIMO) links are considered. Here, a link optimizes its spectral efficiency to be a “good neighbor.” The probability of interference is characterized by the probability that the signal power received …


Linear Mmse Receivers For Random Cdma In Wireless Networks With Equal Transmit Powers, Siddhartan Govindasamy, David Staelin Dec 2012

Linear Mmse Receivers For Random Cdma In Wireless Networks With Equal Transmit Powers, Siddhartan Govindasamy, David Staelin

Siddhartan Govindasamy

The performance of single-hop links in ad-hoc wireless systems using direct-sequence (DS) code-division-multiple-access (CDMA) with random signature sequences and linear minimum-mean-square-error (MMSE) receivers is investigated. Expressions for the average signal-to-interference-plus-noise-ratio (SINR) and spectral efficiency (b s-1 Hz-1 link-1) were derived for a representative link in the presence of interferers distributed randomly on a plane with uniform area density p interferers m-2. Nodes transmit with equal power P, which decays with distance r as r-alpha. An expression for the optimum spreading factor given system parameters is also provided. It is found that for …


Asymptotic Spectral Efficiency Of Multiantenna Links In Wireless Networks With Limited Tx Csi, Siddhartan Govindasamy, Daniel Bliss, David Staelin Dec 2012

Asymptotic Spectral Efficiency Of Multiantenna Links In Wireless Networks With Limited Tx Csi, Siddhartan Govindasamy, Daniel Bliss, David Staelin

Siddhartan Govindasamy

An asymptotic technique is presented for finding the spectral efficiency of multiantenna links in spatially distributed wireless networks where transmitters have channel-state-information (CSI) corresponding to their target receiver. Transmitters are assumed to transmit independent data streams on a limited number of channel modes which limits the rank of transmit covariance matrices. An approximation for the spectral efficiency in the interference-limited regime as a function of link-length, interferer density, number of antennas per receiver and transmitter, number of transmit streams, and path-loss exponent is derived. It is found that targeted-receiver CSI, which can be acquired with low overhead in duplex systems …


Asymptotic Data Rates Of Receive-Diversity Systems With Mmse Estimation And Interferers At Correlated Locations, Siddhartan Govindasamy Dec 2012

Asymptotic Data Rates Of Receive-Diversity Systems With Mmse Estimation And Interferers At Correlated Locations, Siddhartan Govindasamy

Siddhartan Govindasamy

An asymptotic technique is presented to characterize the bits/symbol achievable on a representative wireless link in a spatially distributed network with active interferers at correlated positions, N receive diversity branches, and linear Minimum-Mean-Square-Error (MMSE) receivers. The models analyzed include analogs to Matern type I and type II networks. It is found that for our network models, with large N, the correlation between interferer positions does not significantly influence the bits/symbol resulting in simple approximations for the data rates achievable in such networks with moderately large numbers of diversity branches.


Spectral Efficiency Of Wireless Networks With Multi-Antenna Base Stations And Spatially Distributed Nodes, Siddhartan Govindasamy, Daniel Bliss, David Staelin Dec 2012

Spectral Efficiency Of Wireless Networks With Multi-Antenna Base Stations And Spatially Distributed Nodes, Siddhartan Govindasamy, Daniel Bliss, David Staelin

Siddhartan Govindasamy

We analyze networks with wireless nodes distributed randomly in space, transmitting simultaneously in the same channel to their nearest base-stations using a simple power control algorithm. Base-stations are on a hexagonal grid and have N optimally-phased antennas. We derive the asymptotic mean upstream spectral efficiency(validated by simulation) as a function of N, wireless-node density, base-station separation, and path-loss-exponent which controls signal attenuation with distance. These results indicate that mean per-link spectralefficiency is constant if the number of receive antennas or density of base-stations is increased linearly withwireless node density. They also improve our understanding of systems like city-wide wireless Internet …


Casting A Wider Net, Lynn Stein Nov 2012

Casting A Wider Net, Lynn Stein

Lynn Andrea Stein

This article is a book review of Mung Chiang's book Networked Life: 20 Questions and Answers. In this text intended for both classroom and online learning, Chiang uses questions about our online lives to explore the technology and computer science behind the Internet, wireless, and Web industries.


Reviewing The American University Law Review On Extraterritoriality: A Critical Response To Viki Economides, Note, Tianrui Group Co. V. Itc: The Dubious Status Of Extraterritoriality And The Domestic Industry Requirement Requirement Of Section 337(Link), Jonathan R. K. Stroud Nov 2012

Reviewing The American University Law Review On Extraterritoriality: A Critical Response To Viki Economides, Note, Tianrui Group Co. V. Itc: The Dubious Status Of Extraterritoriality And The Domestic Industry Requirement Requirement Of Section 337(Link), Jonathan R. K. Stroud

Jonathan R. K. Stroud

Recently, the Federal Circuit upheld the Commission’s decision to exclude goods based on a trade secret violation that largely happened abroad. The American University Law Review critiqued that decision on two grounds: First, that a presumption against extraterritorial application of U.S. law applied; and second, that licensing alone could not establish a domestic industry. The American University Law Review's critique remains incomplete, however, as the Federal Circuit correctly decided the case for at least two reasons. first, the Federal Circuit correctly applied the “extraterritorial presumption” canon of construction; and second, the recent Federal Circuit decision in InterDigital Communications LLC v. …


Developing Regional Building Inventories: Lessons From The Field, Thalia Anagnos, Mary Comerio, Christine Goulet, Peter J. May, Marjorie Greene, David L. Mccormick, David Bonowitz Nov 2012

Developing Regional Building Inventories: Lessons From The Field, Thalia Anagnos, Mary Comerio, Christine Goulet, Peter J. May, Marjorie Greene, David L. Mccormick, David Bonowitz

Thalia Anagnos

Between 2008 and 2011 members of the Concrete Coalition completed numerous building inventories of California cities to assemble a database of California pre-1980 concrete buildings. Inventory collectors used a variety of data sources ranging from county assessors files to Sanborn maps and satellite images. Sidewalk surveys were used to corroborate data collected from multiple sources, and a regression model was developed to extrapolate data to cities where detailed inventory collection was not possible. Lessons drawn from inventories of three cities – Alameda, Los Angeles, and San Francisco – indicate that no single approach can be recommended, but instead the approach …


Effects Of Electrostatic Correlations On Electrokinetic Phenomena, Brian Storey, Martin Bazant Oct 2012

Effects Of Electrostatic Correlations On Electrokinetic Phenomena, Brian Storey, Martin Bazant

Brian Storey

The classical theory of electrokinetic phenomena is based on the mean-field approximation that the electric field acting on an individual ion is self-consistently determined by the local mean charge density. This paper considers situations, such as concentrated electrolytes, multivalent electrolytes, or solvent-free ionic liquids, where the mean-field approximation breaks down. A fourth-order modified Poisson equation is developed that captures the essential features in a simple continuum framework. The model is derived as a gradient approximation for nonlocal electrostatics of interacting effective charges, where the permittivity becomes a differential operator, scaled by a correlation length. The theory is able to capture …


An Interactive Exploration Of Gender And Engineering: Unpacking The Experience, Debbie Chachra, Lynn Stein, Alisha Sarang-Sieminski, Caitrin Lynch, Yevgeniya Zastavker Sep 2012

An Interactive Exploration Of Gender And Engineering: Unpacking The Experience, Debbie Chachra, Lynn Stein, Alisha Sarang-Sieminski, Caitrin Lynch, Yevgeniya Zastavker

Lynn Andrea Stein

The engineering student experience is understood to differ for male and female students; gendered interactions affect the development of academic and professional role confidence, as well as engineering identity. The purpose of this session is twofold. First, we aim to introduce participants to concepts of gender schemas, privilege, and identity using a range of interactive activities, including brainstorming and structured discussion. Second, we intend to share information about and obtain feedback on a Gender Discussion Exploration Kit, which the participants will be encouraged to review, use, and share at their home institutions.


Vacuum Microelectronic Integrated Differential Amplifier, S. Hsu, W. Kang, J. Davidson, J. Huang, David Kerns, Jr. Aug 2012

Vacuum Microelectronic Integrated Differential Amplifier, S. Hsu, W. Kang, J. Davidson, J. Huang, David Kerns, Jr.

David V. Kerns

Reported is a novel vacuum field emission transistor (VFET) differential amplifier (diff-amp) utilising nanocrystalline diamond emitters with self-aligned gate partitions. The integrated VFET diff-amp was fabricated by a dual-mask self-aligned mould transfer method in conjunction with chemical vapour deposited nanodiamond. Identical pairs of devices with well-matched field emission transistor characteristics were obtained, realising a negligible common-mode gain, high differential-mode gain, and large common-mode rejection ratio (CMRR) of 55 dB. The emission current was validated by a modified Fowler-Nordheim equation in transistor configuration, and the CMRR was modelled by an equivalent half-circuit with the calculated result found to agree well with …


Editorial: Social Implications Of Technology- “Il Buono, Il Brutto, Il Cattivo”, Katina Michael Aug 2012

Editorial: Social Implications Of Technology- “Il Buono, Il Brutto, Il Cattivo”, Katina Michael

Professor Katina Michael

Late last year, IEEE SSIT was invited to put together a paper for the centennial edition of Proceedings of the IEEE that was published in May 2012. The paper titled, “Social Implications of Technology: The Past, the Present, and the Future,” brought together five members of SSIT with varying backgrounds, and two intense months of collaboration and exchange of ideas. I personally felt privileged to be working with Karl D. Stephan, Emily Anesta, Laura Jacobs and M.G. Michael on this project.


In-Situ Investigation Of Slurry Flow Fields During Cmp, N. Mueller, Chris Rogers, Vincent Manno, Robert White, M. Moinpour Aug 2012

In-Situ Investigation Of Slurry Flow Fields During Cmp, N. Mueller, Chris Rogers, Vincent Manno, Robert White, M. Moinpour

Vincent P. Manno

The objective of this work is to obtain in situ slurry fluid flow data during the chemical mechanical planarization (CMP) process. Slurry flow affects the material removal processes, the creation of defects, and consumable use during CMP, and therefore impacts the cost and quality of polishing. Wafer-scale flow visualization using seeded slurry was accomplished for a variable applied load ( downforce), wafer rotation speed (0 and ), slurry injection locations, and various pad types (flat, grooved, and AC grooved). In situ pad conditioning was employed in all experiments. The data indicated complex slurry flow fields on the pad surface in …


Thermoelectric Module-Variable Conductance Heat Pipe Assemblies For Reduced Power Temperature Control, Corey Melnick, Marc Hodes, Gennady Ziskind, Martin Cleary, Vincent Manno Aug 2012

Thermoelectric Module-Variable Conductance Heat Pipe Assemblies For Reduced Power Temperature Control, Corey Melnick, Marc Hodes, Gennady Ziskind, Martin Cleary, Vincent Manno

Vincent P. Manno

Thermoelectric modules (TEMs) are used to precisely maintain the setpoint temperature of photonic components generating variable heat loads under varying ambient conditions. The non-component side of TEMs is mounted onto conventional heat sinks (CHSs). At any combination of setpoint temperature, heat load and ambient temperature, there is a unique thermal resistance between the non-component side of a TEM and the ambient corresponding to minimal TEM power consumption. Indeed, a zero thermal resistance heat sink minimizes power consumption when a TEM operates in refrigeration mode, but when it operates in heating mode a relatively high thermal resistance one is optimal. This …


Stick-Slip Transitions In Chemical Mechanical Planarization, J. Vlahakis, Vincent Manno, Chris Rogers, Robert White Aug 2012

Stick-Slip Transitions In Chemical Mechanical Planarization, J. Vlahakis, Vincent Manno, Chris Rogers, Robert White

Vincent P. Manno

As semiconductor device sizes continue to shrink and economic realities drive ever increasing yield targets, achieving wafer scale planarity through the application of chemical mechanical planarization (CMP) has become increasingly challenging. The dynamics of the wafer–pad interface is critical to maintaining this uniformity. Utilizing measured friction coefficients (0.3–0.6), we report on the transitions from a smooth planarization regime to a stick-slip regime and vice versa over a set of two applied vertical loads and three relative velocities during the CMP process. Finally, we note a correlation between time spent in a stick-slip regime and platen velocity.


Optimized Thermoelectric Module-Heat Sink Assemblies For Precision Temperature Control, Rui Zhang, David Brooks, Marc Hodes, Vincent Manno Aug 2012

Optimized Thermoelectric Module-Heat Sink Assemblies For Precision Temperature Control, Rui Zhang, David Brooks, Marc Hodes, Vincent Manno

Vincent P. Manno

Robustprecision temperature control of photonics components is achieved by mountingthem on thermoelectric modules (TEMs) which are in turn mountedon heat sinks. However, the power consumption of TEMs ishigh because high currents are driven through Bi2Te3-based semiconducting materialswith high electrical resistivity and finite thermal conductivity. This problemis exacerbated when the ambient temperature surrounding a TEM variesin the usual configuration where the air-cooled heat sink aTEM is mounted to is of specified thermal resistance. Indeed,heat sinks of negligible and relatively high thermal resistances minimizeTEM power consumption for sufficiently high and low ambient temperatures,respectively. Optimized TEM-heat sink assemblies reduce the severity of thisproblem. …


Measurement Of Microscale Shear Forces During Chemical Mechanical Planarization, Robert White, Andrew Mueller, Minchul Shin, Douglas Gauthier, Vincent Manno, Chris Rogers Aug 2012

Measurement Of Microscale Shear Forces During Chemical Mechanical Planarization, Robert White, Andrew Mueller, Minchul Shin, Douglas Gauthier, Vincent Manno, Chris Rogers

Vincent P. Manno

Polydimethylsiloxane (PDMS) posts with a diameter of 80 mu m were used to measure the shearing forces at the wafer-pad interface during chemical mechanical planarization (CMP). Measurements are made at 10 kHz with measurable forces between 40 and 400 mu N. The structures were polished using a stiff, ungrooved pad and 3 wt % fumed silica slurry at velocities of 0.3 and 0.6 m/s and average wafer-pad normal load of 5.0 and 9.1 kPa. Due to the small fraction of the pad that contacts the wafer, the local microscale forces can be much larger than the global average force might …


Transient Thermomechanical Simulation Of Laser Hammering In Optoelectronic Package Manufacturing, Ben Ting, Vincent Manno Aug 2012

Transient Thermomechanical Simulation Of Laser Hammering In Optoelectronic Package Manufacturing, Ben Ting, Vincent Manno

Vincent P. Manno

Laser hammering (LH) is a process used in the manufacturing of butterfly optoelectronic packages to correct laser-to-fiber misalignment that occurs when the semiconductor lasers are welded in place. High-power, precisely positioned pulsed lasers are used in LH to induce deformation of the fiber support housing to, in turn, induce realignment. A thermomechanical modeling study of LH is reported in this paper, which focuses on the degree to which a steady-state model can predict the asymptotic state of a transient response subjected to a periodic laser excitation. A baseline, two-dimensional fiber mounting/ferrule geometry is employed in a finite element analysis simulation …


Simulated Effects Of Measurement Noise On Contact Measurements Between Rough And Smooth Surfaces, Caprice Gray, Robert White, Vincent Manno, Chris Rogers Aug 2012

Simulated Effects Of Measurement Noise On Contact Measurements Between Rough And Smooth Surfaces, Caprice Gray, Robert White, Vincent Manno, Chris Rogers

Vincent P. Manno

To test the accuracy of optically measuring contact, we examined the height distribution histogram of a simulated rough surface contacting a smooth surface. We qualified the technique sensitivity as a function of the inverse signal-to-noise ratio having values ranging from 0 to 0.3. An explanation of how the analysis technique can be applied to Dual Emission Laser-Induced Fluorescence (DELIF) measurements is provided.