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• 1. [Article] Reversible Logic Synthesis Using a Non-blocking Order Search

  Reversible logic is an emerging area of research. With the rapid growth of markets such as mobile computing, power dissipation has become an increasing concern for designers (temperature range limitations, ...

  Citation × Citation Citation Abstract Copy Title: Reversible Logic Synthesis Using a Non-blocking Order Search Author: Patino, Alberto Year: 2010 Reversible logic is an emerging area of research. With the rapid growth of markets such as mobile computing, power dissipation has become an increasing concern for designers (temperature range limitations, generating smaller transistors) as well as customers (battery life, overheating). The main benefit of utilizing reversible logic is that there exists, theoretically, zero power dissipation. The synthesis of circuits is an important part of any design cycle. The circuit used to realize any specification must meet detailed requirements for both layout and manufacturing. Quantum cost is the main metric used in reversible logic. Many algorithms have been proposed thus far which result in both low gate count and quantum cost. In this thesis the AP algorithm is introduced. The goal of the algorithm is to drive quantum cost down by using multiple non-blocking orders, a breadth first search, and a quantum cost reduction transformation. The results shown by the AP algorithm demonstrate that the resulting quantum cost for well-known benchmarks are improved by at least 9% and up to 49%. Title: Reversible Logic Synthesis Using a Non-blocking Order Search Author: Patino, Alberto Year: 2010 Reversible logic is an emerging area of research. With the rapid growth of markets such as mobile computing, power dissipation has become an increasing concern for designers (temperature range limitations, generating smaller transistors) as well as customers (battery life, overheating). The main benefit of utilizing reversible logic is that there exists, theoretically, zero power dissipation. The synthesis of circuits is an important part of any design cycle. The circuit used to realize any specification must meet detailed requirements for both layout and manufacturing. Quantum cost is the main metric used in reversible logic. Many algorithms have been proposed thus far which result in both low gate count and quantum cost. In this thesis the AP algorithm is introduced. The goal of the algorithm is to drive quantum cost down by using multiple non-blocking orders, a breadth first search, and a quantum cost reduction transformation. The results shown by the AP algorithm demonstrate that the resulting quantum cost for well-known benchmarks are improved by at least 9% and up to 49%. Close

• 2. [Article] Design and Prototyping of an Antenna-Coupled Cryotron

  Grid-scale integration of renewable energy sources and smart grid devices has created new demands in flexible power conversion. State-of-the-art semiconductor power switches present limitations in power ...

  Citation × Citation Citation Abstract Copy Title: Design and Prototyping of an Antenna-Coupled Cryotron Author: Jensen, Shauna Year: 2014 Grid-scale integration of renewable energy sources and smart grid devices has created new demands in flexible power conversion. State-of-the-art semiconductor power switches present limitations in power handling capability, as well as forward and reverse breakdown voltages. Superconducting materials are a viable alternative due to their robustness against high ampacities, large electric fields and abrupt changes in power flow. This work pays focus to material testing and apparatus design for an antenna-coupled cryotron (ACC), which is a superconducting power switch.Design, fabrication and testing are examined for a longitudinal resonant cavity, paired with monopole transmit and modified slot receive antennae. These couple radio frequency (RF) energy into superconducting thin film niobium (Nb) carrying high current densities (∼105A/cm2), thereby creating an antenna-coupled cryotron.Induced electromagnetic field effects at the receive antenna alter superconductive fluid dynamics. The theorized quality in manipulating this mechanism is a rapid normal-conductivity transition (µs), which affects a switch "off" state. Functional evaluation of the device as a waveguide revealed evanescent mode resonance at frequencies below the waveguide cut-off of ∼18GHz. The thin film Nb was deposited on a quartz dielectric, which penetrated the waveguide and supported evanescent resonances within the structure.Altered resistivity and critical transition-point properties emerged from device testing at applied RF. When the Nb film temperature-dependent coherence length was comparable to its thickness, perpendicular magnetic field application generated an Abrikosov vortex state, energetically favoring a mixed domain condensate. Interaction of the magnetically-induced flux vortex lattice with Lorentz current forces gave rise to resistive changes within the metal. Three resistive transition mechanisms developed: a latch to normal state resistance, attributed to cooper-pair destruction avalanche induced near critical transition points; a small reversible increase in resistance (∼mV), arising from flux-flow within an intermediate state at peak resonance; as well as temporal alterations in superfluid dynamics from disequilibrium in the quasi-particle population. The RF induced superfluid effects were observable in separate terms of electric and thermodynamic fluctuations.Motivation for this work is the eventual design of a high voltage, high current and low cost power switch, able to function where existing semiconductor technology fails. Concentration is paid to the fundamental theory, physics and methodology in conceptual testing and design of prototype ACCs. Assessment focuses on preliminary findings and concludes with next stage design requirements. Title: Design and Prototyping of an Antenna-Coupled Cryotron Author: Jensen, Shauna Year: 2014 Grid-scale integration of renewable energy sources and smart grid devices has created new demands in flexible power conversion. State-of-the-art semiconductor power switches present limitations in power handling capability, as well as forward and reverse breakdown voltages. Superconducting materials are a viable alternative due to their robustness against high ampacities, large electric fields and abrupt changes in power flow. This work pays focus to material testing and apparatus design for an antenna-coupled cryotron (ACC), which is a superconducting power switch.Design, fabrication and testing are examined for a longitudinal resonant cavity, paired with monopole transmit and modified slot receive antennae. These couple radio frequency (RF) energy into superconducting thin film niobium (Nb) carrying high current densities (∼105A/cm2), thereby creating an antenna-coupled cryotron.Induced electromagnetic field effects at the receive antenna alter superconductive fluid dynamics. The theorized quality in manipulating this mechanism is a rapid normal-conductivity transition (µs), which affects a switch "off" state. Functional evaluation of the device as a waveguide revealed evanescent mode resonance at frequencies below the waveguide cut-off of ∼18GHz. The thin film Nb was deposited on a quartz dielectric, which penetrated the waveguide and supported evanescent resonances within the structure.Altered resistivity and critical transition-point properties emerged from device testing at applied RF. When the Nb film temperature-dependent coherence length was comparable to its thickness, perpendicular magnetic field application generated an Abrikosov vortex state, energetically favoring a mixed domain condensate. Interaction of the magnetically-induced flux vortex lattice with Lorentz current forces gave rise to resistive changes within the metal. Three resistive transition mechanisms developed: a latch to normal state resistance, attributed to cooper-pair destruction avalanche induced near critical transition points; a small reversible increase in resistance (∼mV), arising from flux-flow within an intermediate state at peak resonance; as well as temporal alterations in superfluid dynamics from disequilibrium in the quasi-particle population. The RF induced superfluid effects were observable in separate terms of electric and thermodynamic fluctuations.Motivation for this work is the eventual design of a high voltage, high current and low cost power switch, able to function where existing semiconductor technology fails. Concentration is paid to the fundamental theory, physics and methodology in conceptual testing and design of prototype ACCs. Assessment focuses on preliminary findings and concludes with next stage design requirements. Close

• 3. [Article] Stream-Associated Amphibian Habitat Assessment in the Portland-Vancouver Metropolitan Region

  This study assessed the influence of landscape development on stream-associated amphibians in forested riparian areas within the Portland-Vancouver metropolitan region. Human alteration of landscapes may ...

  Citation × Citation Citation Abstract Copy Title: Stream-Associated Amphibian Habitat Assessment in the Portland-Vancouver Metropolitan Region Author: Dietrich, Andrew Evans Year: 2012 This study assessed the influence of landscape development on stream-associated amphibians in forested riparian areas within the Portland-Vancouver metropolitan region. Human alteration of landscapes may dramatically affect the ecology of neighboring aquatic systems. It was hypothesized that lotic amphibians would be negatively associated with greater amounts of landscape development and positively associated with forested area within the surrounding watershed. Thirty-seven 1st-3rd order streams were sampled between June 21st and September 21st in 2011. Streams potentially providing adequate habitat for stream-obligate amphibians were randomly selected. Amphibians were surveyed along 30-meter stream transects using an active-cover search (ACS). Environmental variables associated with development in surrounding landscapes were measured in situ. GIS delineation was conducted to define landscape-scale variables at stratified distances from riparian networks up-stream of each site via the utilization of the 2006 NLCD dataset and a finer-scale, regional dataset compiled by the Institute for Natural Resources (INR). Amphibians were detected at seventeen of the thirty-seven sampled streams. The most commonly detected species were Dicamptadon tenebrosus, Plethadon vehiculum and Plethadon dunni. Streams where amphibians were observed had lower average water temperature and conductivity, coarser stream substrate and were located on public property more often than streams where no amphibians were detected. Landscape variables were most significant to amphibians within 100 and 200 meters of the upstream stream network. Occupancy of a site by facultative species was best explained by the proportion of mixed forest in the surrounding watershed (R2=0.343, p<0.001). Occupancy of a stream by obligate species was best predicted by measurements of water quality and in-stream cover (Water Temperature: R2=0.275, p<0.001; Water Conductivity: R2=0.248, p<0.001; Cover: R2=0.323, p<0.001). Occupancy of stream refugia by all observed amphibians was positively influenced by higher percentages of forest cover and lower percentages of urban development and herbaceous vegetation in the surrounding watershed. Results of this study indicate that urban refugia must contain adequate riparian forest area, coarse stream substrate and clean, cool water to sustain stream-amphibian communities. Protection of remnant forested headwater stream networks is essential to the conservation of lotic amphibians in this urbanized region. Title: Stream-Associated Amphibian Habitat Assessment in the Portland-Vancouver Metropolitan Region Author: Dietrich, Andrew Evans Year: 2012 This study assessed the influence of landscape development on stream-associated amphibians in forested riparian areas within the Portland-Vancouver metropolitan region. Human alteration of landscapes may dramatically affect the ecology of neighboring aquatic systems. It was hypothesized that lotic amphibians would be negatively associated with greater amounts of landscape development and positively associated with forested area within the surrounding watershed. Thirty-seven 1st-3rd order streams were sampled between June 21st and September 21st in 2011. Streams potentially providing adequate habitat for stream-obligate amphibians were randomly selected. Amphibians were surveyed along 30-meter stream transects using an active-cover search (ACS). Environmental variables associated with development in surrounding landscapes were measured in situ. GIS delineation was conducted to define landscape-scale variables at stratified distances from riparian networks up-stream of each site via the utilization of the 2006 NLCD dataset and a finer-scale, regional dataset compiled by the Institute for Natural Resources (INR). Amphibians were detected at seventeen of the thirty-seven sampled streams. The most commonly detected species were Dicamptadon tenebrosus, Plethadon vehiculum and Plethadon dunni. Streams where amphibians were observed had lower average water temperature and conductivity, coarser stream substrate and were located on public property more often than streams where no amphibians were detected. Landscape variables were most significant to amphibians within 100 and 200 meters of the upstream stream network. Occupancy of a site by facultative species was best explained by the proportion of mixed forest in the surrounding watershed (R2=0.343, p<0.001). Occupancy of a stream by obligate species was best predicted by measurements of water quality and in-stream cover (Water Temperature: R2=0.275, p<0.001; Water Conductivity: R2=0.248, p<0.001; Cover: R2=0.323, p<0.001). Occupancy of stream refugia by all observed amphibians was positively influenced by higher percentages of forest cover and lower percentages of urban development and herbaceous vegetation in the surrounding watershed. Results of this study indicate that urban refugia must contain adequate riparian forest area, coarse stream substrate and clean, cool water to sustain stream-amphibian communities. Protection of remnant forested headwater stream networks is essential to the conservation of lotic amphibians in this urbanized region. Close

• 4. [Article] Biostratigraphy of the Type Yamhill Formation, Polk County, Oregon

  One hundred and seventy-four species and varieties of fossil Foraminifera are recorded from thirty-eight localities in the Siletz River Volcanics, Yamhill and Nestucca Formations exposed along Mill and ...

  Citation × Citation Citation Abstract Copy Title: Biostratigraphy of the Type Yamhill Formation, Polk County, Oregon Author: Gaston, Larry R. Year: 1974 One hundred and seventy-four species and varieties of fossil Foraminifera are recorded from thirty-eight localities in the Siletz River Volcanics, Yamhill and Nestucca Formations exposed along Mill and Gooseneck Creeks, in the Northern Coast Range of Oregon. Marginulina holmesi is described as new. The Foraminifera indicate that this sequence was deposited during late Ulatisian and Narizian time, in marine waters at bathyal or lower neritic depths, with cool surface temperatures. The Yamhill Formation can be correlated with Moody Shale member of the Toledo Formation and the Coaledo Formation of Oregon; the McIntosh and Aldwell Formations of Washington; and the upper part of the Canoas siltstone member of the Kreyenhagen Formation and the Alhambra Formation of California. It is proposed to modify, in part, the type section of the Yamhill Formation. Approximately 2.2 miles of the section, south of the Yamhill River Fault, are excluded from the original type area. Biostratigraphic studies of foraminiferal faunae from adjacent sides of the Yamhill River Fault suggest only minor vertical displacement. Title: Biostratigraphy of the Type Yamhill Formation, Polk County, Oregon Author: Gaston, Larry R. Year: 1974 One hundred and seventy-four species and varieties of fossil Foraminifera are recorded from thirty-eight localities in the Siletz River Volcanics, Yamhill and Nestucca Formations exposed along Mill and Gooseneck Creeks, in the Northern Coast Range of Oregon. Marginulina holmesi is described as new. The Foraminifera indicate that this sequence was deposited during late Ulatisian and Narizian time, in marine waters at bathyal or lower neritic depths, with cool surface temperatures. The Yamhill Formation can be correlated with Moody Shale member of the Toledo Formation and the Coaledo Formation of Oregon; the McIntosh and Aldwell Formations of Washington; and the upper part of the Canoas siltstone member of the Kreyenhagen Formation and the Alhambra Formation of California. It is proposed to modify, in part, the type section of the Yamhill Formation. Approximately 2.2 miles of the section, south of the Yamhill River Fault, are excluded from the original type area. Biostratigraphic studies of foraminiferal faunae from adjacent sides of the Yamhill River Fault suggest only minor vertical displacement. Close

• 5. [Article] Constant Interface Temperature Reliability Assessment Method: An Alternative Method for Testing Thermal Interface Material in Products

  As electronic packages and their thermal solutions become more complex the reliability margins in the thermal solutions diminish and become less tolerant to errors in reliability predictions. The current ...

  Citation × Citation Citation Abstract Copy Title: Constant Interface Temperature Reliability Assessment Method: An Alternative Method for Testing Thermal Interface Material in Products Author: Amoah-Kusi, Christian Year: 2015 As electronic packages and their thermal solutions become more complex the reliability margins in the thermal solutions diminish and become less tolerant to errors in reliability predictions. The current method of thermally stress testing thermal solutions can be over or under predicting end of life thermal performance. Benefits of accurate testing and modeling are improved silicon yield in manufacturing, improved performance, lower cost thermal solutions, and shortened test times. The current method of thermally stress testing is to place the entire unit in an elevated isothermal temperature and periodically measure thermal performance. Isothermally aging is not an accurate representation of how the unit will be used by the customer and does not capture the thermal gradients and mechanical stresses due to different coefficients of thermal expansion of the materials used in the thermal solution. A new testing system, CITRAM which is an acronym for Constant Interface Temperature Reliability Method, has been developed that uses an electronic test board. The approach captures the thermal and mechanical stresses accurately and improves test time by 20-30% as a result of automation. Through this study a difference in the two methods has been identified and the new CITRAM method should be adopted as current practice. Title: Constant Interface Temperature Reliability Assessment Method: An Alternative Method for Testing Thermal Interface Material in Products Author: Amoah-Kusi, Christian Year: 2015 As electronic packages and their thermal solutions become more complex the reliability margins in the thermal solutions diminish and become less tolerant to errors in reliability predictions. The current method of thermally stress testing thermal solutions can be over or under predicting end of life thermal performance. Benefits of accurate testing and modeling are improved silicon yield in manufacturing, improved performance, lower cost thermal solutions, and shortened test times. The current method of thermally stress testing is to place the entire unit in an elevated isothermal temperature and periodically measure thermal performance. Isothermally aging is not an accurate representation of how the unit will be used by the customer and does not capture the thermal gradients and mechanical stresses due to different coefficients of thermal expansion of the materials used in the thermal solution. A new testing system, CITRAM which is an acronym for Constant Interface Temperature Reliability Method, has been developed that uses an electronic test board. The approach captures the thermal and mechanical stresses accurately and improves test time by 20-30% as a result of automation. Through this study a difference in the two methods has been identified and the new CITRAM method should be adopted as current practice. Close

• 6. [Article] Biological Treatment of Leachates of Microaerobic Fermentation

  Microaerobic fermentation (MF) is a process of controlled degradation of organic waste material that occurs in enclosed fermentors under micro-aerobic conditions at near-room temperature. MF processing ...

  Citation × Citation Citation Abstract Copy Title: Biological Treatment of Leachates of Microaerobic Fermentation Author: Alattar, Manar Arica Year: 2012 Microaerobic fermentation (MF) is a process of controlled degradation of organic waste material that occurs in enclosed fermentors under micro-aerobic conditions at near-room temperature. MF processing of vegetal materials progresses to endpoints in about 2-5 weeks. During MF processing, an acidic leachate rich in organic acids and alcohols is produced. The research presented in this thesis focuses on the efficiency of MF pre-processing of feedstock containing fibrous lignocellulosic (FLC) materials; efficiency of microbial and insect larvae-based treatments of MF leachate; tolerance of the Black Soldier fly larvae (BSFL) to various biological inhibitors common in leachate; and effectiveness of using MF and BSFL solid and liquid processing products as agricultural fertilizers. Results indicate that MF is unsuitable for pre-processing of FLC materials. Enhanced MF leachate treatment may increase efficiency of FLC processing though. Leachate can be efficiently treated using BSFL which decrease overall leachate toxicity. BSFL are able to tolerate increased levels of many of the biological inhibitors within the leachate including ethanol, acetate, pH extremes and temperature. MF solid residues increased corn plant growth when amended into soil, but residues resulting from BSFL processing of solid organics stunted corn plant growth. Short-term phytotoxicity of MF leachate was eliminated by diluting it 10 - 10,000 times or through BSFL processing. It can be concluded that MF processing of organics is beneficial for producing solid soil amendments from non-FLC materials and that dilution or BSFL treatment of MF leachate leads to a beneficial liquid fertilizer. Title: Biological Treatment of Leachates of Microaerobic Fermentation Author: Alattar, Manar Arica Year: 2012 Microaerobic fermentation (MF) is a process of controlled degradation of organic waste material that occurs in enclosed fermentors under micro-aerobic conditions at near-room temperature. MF processing of vegetal materials progresses to endpoints in about 2-5 weeks. During MF processing, an acidic leachate rich in organic acids and alcohols is produced. The research presented in this thesis focuses on the efficiency of MF pre-processing of feedstock containing fibrous lignocellulosic (FLC) materials; efficiency of microbial and insect larvae-based treatments of MF leachate; tolerance of the Black Soldier fly larvae (BSFL) to various biological inhibitors common in leachate; and effectiveness of using MF and BSFL solid and liquid processing products as agricultural fertilizers. Results indicate that MF is unsuitable for pre-processing of FLC materials. Enhanced MF leachate treatment may increase efficiency of FLC processing though. Leachate can be efficiently treated using BSFL which decrease overall leachate toxicity. BSFL are able to tolerate increased levels of many of the biological inhibitors within the leachate including ethanol, acetate, pH extremes and temperature. MF solid residues increased corn plant growth when amended into soil, but residues resulting from BSFL processing of solid organics stunted corn plant growth. Short-term phytotoxicity of MF leachate was eliminated by diluting it 10 - 10,000 times or through BSFL processing. It can be concluded that MF processing of organics is beneficial for producing solid soil amendments from non-FLC materials and that dilution or BSFL treatment of MF leachate leads to a beneficial liquid fertilizer. Close

• 7. [Article] Solid State Pre-Formed Electronics Adhesive (SPEA)

  In mobile and handheld consumer electronic markets, product use conditions drive the requirement for mechanical strength and device durability. The majority of relatively large form factor electronic components ...

  Citation × Citation Citation Abstract Copy Title: Solid State Pre-Formed Electronics Adhesive (SPEA) Author: Cope, Alexander Randon Year: 2013 In mobile and handheld consumer electronic markets, product use conditions drive the requirement for mechanical strength and device durability. The majority of relatively large form factor electronic components in a laptop, mobile internet device, PDA, or mobile phone use an adhesive as a stiffener to help protect the component from physical stresses imposed by daily wear and tear. Described herein is an innovative solution referred to as Solid State Pre-Formed Electronics Adhesive (SPEA), which enables a decrease in circuit board manufacturing throughput time while increasing mechanical durability with a consistent and characterized adhesive application process. Today, many consumer electronic ODM's (Original Design Manufacturers) and CM's (Contract Manufacturers) use a liquid adhesive dispensed after placement of an electronic component within the SMT (Surface Mount Technology) process. On average, this adds up to 60 seconds to the throughput time of a typical motherboard as the material needs to be applied and then cured. In addition, the current adhesive dispense application process is not tightly controlled and is highly variable depending on operator, material type, and circuit board density. Data will demonstrate that the effect of the adhesive deposition profile and consistency in application directly affects repeatable margin increase gains in a dynamic stress event. In partnership with a specialty chemical company, a unique thermoset epoxy compound was designed to provide maximum component to circuit board interconnect strength while maintaining its form at ambient temperatures. When applied to electronics manufacturing, the compound has the following advantages over current solutions: 1. Reduced Manufacturing Processing Time: Enables a solution that can be transitioned transparently into a circuit board manufacturing facility which reduces the average processing time for a typical device motherboard. 2. Improved Application Repeatability: Enables a solution that increases adhesive deposition consistency and placement repeatability, critical in achieving improved dynamic performance. 3. Delivers a Reference, Characterized Solution: Current industry adhesive application techniques and materials vary widely and component manufacturers cannot validate reliability performance with a confident baseline. This is due to the high variability of performance in commercially available adhesives. SPEA provides a characterized adhesive solution with a clear baseline margin increase on which to evaluate dynamically stressed system performance. The need to continually increase the resistance to component damage through dynamic testing is a critical aspect to consider given market trends and device roadmaps. Large component manufacturers have the opportunity to further embed themselves into untapped markets where portability and performance converge and drive the need for more robust packaging solutions. The development and application of SPEA will continue to maintain silicon and packaging reliability as consumer devices continue to shrink, becoming ever more portable. Title: Solid State Pre-Formed Electronics Adhesive (SPEA) Author: Cope, Alexander Randon Year: 2013 In mobile and handheld consumer electronic markets, product use conditions drive the requirement for mechanical strength and device durability. The majority of relatively large form factor electronic components in a laptop, mobile internet device, PDA, or mobile phone use an adhesive as a stiffener to help protect the component from physical stresses imposed by daily wear and tear. Described herein is an innovative solution referred to as Solid State Pre-Formed Electronics Adhesive (SPEA), which enables a decrease in circuit board manufacturing throughput time while increasing mechanical durability with a consistent and characterized adhesive application process. Today, many consumer electronic ODM's (Original Design Manufacturers) and CM's (Contract Manufacturers) use a liquid adhesive dispensed after placement of an electronic component within the SMT (Surface Mount Technology) process. On average, this adds up to 60 seconds to the throughput time of a typical motherboard as the material needs to be applied and then cured. In addition, the current adhesive dispense application process is not tightly controlled and is highly variable depending on operator, material type, and circuit board density. Data will demonstrate that the effect of the adhesive deposition profile and consistency in application directly affects repeatable margin increase gains in a dynamic stress event. In partnership with a specialty chemical company, a unique thermoset epoxy compound was designed to provide maximum component to circuit board interconnect strength while maintaining its form at ambient temperatures. When applied to electronics manufacturing, the compound has the following advantages over current solutions: 1. Reduced Manufacturing Processing Time: Enables a solution that can be transitioned transparently into a circuit board manufacturing facility which reduces the average processing time for a typical device motherboard. 2. Improved Application Repeatability: Enables a solution that increases adhesive deposition consistency and placement repeatability, critical in achieving improved dynamic performance. 3. Delivers a Reference, Characterized Solution: Current industry adhesive application techniques and materials vary widely and component manufacturers cannot validate reliability performance with a confident baseline. This is due to the high variability of performance in commercially available adhesives. SPEA provides a characterized adhesive solution with a clear baseline margin increase on which to evaluate dynamically stressed system performance. The need to continually increase the resistance to component damage through dynamic testing is a critical aspect to consider given market trends and device roadmaps. Large component manufacturers have the opportunity to further embed themselves into untapped markets where portability and performance converge and drive the need for more robust packaging solutions. The development and application of SPEA will continue to maintain silicon and packaging reliability as consumer devices continue to shrink, becoming ever more portable. Close

• 8. [Article] The Tensile Strength of Liquid Nitrogen

  The tensile strength or the negative pressure required to induce cavitation in a pure liquid has been a puzzling subject. On one hand, the classical nucleation theory has met great success in predicting ...

  Citation × Citation Citation Abstract Copy Title: The Tensile Strength of Liquid Nitrogen Author: Huang, Jian Year: 1992 The tensile strength or the negative pressure required to induce cavitation in a pure liquid has been a puzzling subject. On one hand, the classical nucleation theory has met great success in predicting the nucleation rates of superheated liquids. On the other hand, most of reported experimental values of the tensile strength for different liquids are far below the prediction from the classical nucleation theory. In this study, homogeneous nucleation in liquid nitrogen and its tensile strength have been investigated. In order to carry out the measurement of the tensile strength of liquid nitrogen, different approaches for determining the pressure amplitude were studied carefully. It is shown that Raman-Nath theory, as modified by the introduction of an effective interaction length, can be used to determine the pressure amplitude in the focal plane of a focusing ultrasonic transducer. The results obtained from different diffraction orders are consistent and in good agreement with other approaches including Debye's theory and solving the KZK (Khokhlov-Zabolotskaya-Kuznetsov) equation. The results from experiments in water demonstrated that as long as the nonlinearity is not too large, the experimentally determined pressure follows closely the calculated results using either Debye's theory or the KZK equation. In addition, the light diffraction contains enough information to calculate the second-order harmonic in the sound wave. In principle, it is possible that the contribution to the acoustic wave of the higher than the second-order harmonic can be obtained. The measurement of the tensile strength was carried out in a high pressure stainless steel dewar. A High intensity ultrasonic wave was focused into a small volume of liquid nitrogen in a short time period. A probe laser beam passes through the focal region of a concave spherical transducer with small aperture angle and the transmitted light is detected with a photodiode. When the voltage on the transducer reaches a critical point, nucleation in the focal region occurs and a characteristic signal associated with the nucleation was obtained. At this moment, the pressure amplitude at the focus is calculated based on the acoustic power radiated into the liquid. In the experiment, the electrical signal on the transducer is gated at its resonance frequency with gate widths of 20 ~s to 0.2 ms and temperature range from 77 K to near 100 K. The calculated pressure amplitude is in agreement with the prediction of classical nucleation theory for the nucleation rates from 106 to lOll (bubbles/cm3 sec). This work enhances our understanding of the nucleation process in liquids. It provides the direct experimental support that the validity of the classical nucleation theory can be extended to the region of the negative pressure up to 90 atm. This is only the second cryogenic liquid to reach the tensile strength predicted from the classical nucleation theory. Title: The Tensile Strength of Liquid Nitrogen Author: Huang, Jian Year: 1992 The tensile strength or the negative pressure required to induce cavitation in a pure liquid has been a puzzling subject. On one hand, the classical nucleation theory has met great success in predicting the nucleation rates of superheated liquids. On the other hand, most of reported experimental values of the tensile strength for different liquids are far below the prediction from the classical nucleation theory. In this study, homogeneous nucleation in liquid nitrogen and its tensile strength have been investigated. In order to carry out the measurement of the tensile strength of liquid nitrogen, different approaches for determining the pressure amplitude were studied carefully. It is shown that Raman-Nath theory, as modified by the introduction of an effective interaction length, can be used to determine the pressure amplitude in the focal plane of a focusing ultrasonic transducer. The results obtained from different diffraction orders are consistent and in good agreement with other approaches including Debye's theory and solving the KZK (Khokhlov-Zabolotskaya-Kuznetsov) equation. The results from experiments in water demonstrated that as long as the nonlinearity is not too large, the experimentally determined pressure follows closely the calculated results using either Debye's theory or the KZK equation. In addition, the light diffraction contains enough information to calculate the second-order harmonic in the sound wave. In principle, it is possible that the contribution to the acoustic wave of the higher than the second-order harmonic can be obtained. The measurement of the tensile strength was carried out in a high pressure stainless steel dewar. A High intensity ultrasonic wave was focused into a small volume of liquid nitrogen in a short time period. A probe laser beam passes through the focal region of a concave spherical transducer with small aperture angle and the transmitted light is detected with a photodiode. When the voltage on the transducer reaches a critical point, nucleation in the focal region occurs and a characteristic signal associated with the nucleation was obtained. At this moment, the pressure amplitude at the focus is calculated based on the acoustic power radiated into the liquid. In the experiment, the electrical signal on the transducer is gated at its resonance frequency with gate widths of 20 ~s to 0.2 ms and temperature range from 77 K to near 100 K. The calculated pressure amplitude is in agreement with the prediction of classical nucleation theory for the nucleation rates from 106 to lOll (bubbles/cm3 sec). This work enhances our understanding of the nucleation process in liquids. It provides the direct experimental support that the validity of the classical nucleation theory can be extended to the region of the negative pressure up to 90 atm. This is only the second cryogenic liquid to reach the tensile strength predicted from the classical nucleation theory. Close

• 9. [Article] Reversible Circuits Synthesis Based on EXOR-sum of Products of EXOR-sums

  Power dissipation in modern technologies is an important matter and overheating is a severe concern for both manufacturer (impossibility of introducing new and smaller scale technologies and limited temperature ...

  Citation × Citation Citation Abstract Copy Title: Reversible Circuits Synthesis Based on EXOR-sum of Products of EXOR-sums Author: Tran, Linh Hoang Year: 2015 Power dissipation in modern technologies is an important matter and overheating is a severe concern for both manufacturer (impossibility of introducing new and smaller scale technologies and limited temperature range for operating the product) and customer (power supply, which is especially important for mobile systems). One of the main profits that reversible circuit carries is theoretically the zero power dissipation in the sense that it is independent of underlying technology; irreversibility means heat generation. In the other words, reversible circuits may offer a feasible solution in the future that will aid certain reduction of the power loss. Reversible circuits are circuits that do not lose information during computation. These circuits can create unique output vector from each input vector, and vice versa, that is, there is a one-to-one mapping between the input and the output vectors. Historically, the reversible circuits have been inspired by theoretical research in low power electronics as well as practical progress of bit-manipulation transforms in cryptography and computer graphics. Interest in reversible circuit is also sparked by its applications in several up-to-date technologies, such as Nanotechnology, Quantum Computing, Optical Computing, Quantum Dot Cellular Automata, and Low Power Adiabatic CMOS. However, the most important application of reversible circuits is in Quantum Computing. Logic synthesis methodologies for reversible circuits are very different from those for classical CMOS and other technologies. The dissertation introduces a new concept of reversible logic circuits synthesis based on EXOR-sum of Products-of-EXOR-sums (EPOE). The motivation for this work is to reduce the number of the multiple-controlled Toffoli gates as well as the numbers of their inputs. To achieve these reductions the research generalizes from the existing 2-level AND-EXOR structures (ESOP) commonly used in reversible logic to a mixture of 3-level EXOR-AND-EXOR structures and ESOPs. The approaches can be applied to reversible and permutative quantum circuits to synthesize both completely and incompletely specified single-output functions as well as multiple-output functions. This dissertation describes the research intended to examine the methods to synthesize reversible circuits based on this new concept. The examinations indicate that the synthesis of reversible logic circuits based on EPOE approach produces circuits with significantly lower quantum costs than the common ESOP approach. Title: Reversible Circuits Synthesis Based on EXOR-sum of Products of EXOR-sums Author: Tran, Linh Hoang Year: 2015 Power dissipation in modern technologies is an important matter and overheating is a severe concern for both manufacturer (impossibility of introducing new and smaller scale technologies and limited temperature range for operating the product) and customer (power supply, which is especially important for mobile systems). One of the main profits that reversible circuit carries is theoretically the zero power dissipation in the sense that it is independent of underlying technology; irreversibility means heat generation. In the other words, reversible circuits may offer a feasible solution in the future that will aid certain reduction of the power loss. Reversible circuits are circuits that do not lose information during computation. These circuits can create unique output vector from each input vector, and vice versa, that is, there is a one-to-one mapping between the input and the output vectors. Historically, the reversible circuits have been inspired by theoretical research in low power electronics as well as practical progress of bit-manipulation transforms in cryptography and computer graphics. Interest in reversible circuit is also sparked by its applications in several up-to-date technologies, such as Nanotechnology, Quantum Computing, Optical Computing, Quantum Dot Cellular Automata, and Low Power Adiabatic CMOS. However, the most important application of reversible circuits is in Quantum Computing. Logic synthesis methodologies for reversible circuits are very different from those for classical CMOS and other technologies. The dissertation introduces a new concept of reversible logic circuits synthesis based on EXOR-sum of Products-of-EXOR-sums (EPOE). The motivation for this work is to reduce the number of the multiple-controlled Toffoli gates as well as the numbers of their inputs. To achieve these reductions the research generalizes from the existing 2-level AND-EXOR structures (ESOP) commonly used in reversible logic to a mixture of 3-level EXOR-AND-EXOR structures and ESOPs. The approaches can be applied to reversible and permutative quantum circuits to synthesize both completely and incompletely specified single-output functions as well as multiple-output functions. This dissertation describes the research intended to examine the methods to synthesize reversible circuits based on this new concept. The examinations indicate that the synthesis of reversible logic circuits based on EPOE approach produces circuits with significantly lower quantum costs than the common ESOP approach. Close

• 10. [Article] Effects of Reactive Oxygen Species on Life History Traits of Caenorhabditis elegans

  Evolutionary life history theory predicts that tradeoffs among fitness-related phenotypes will occur as a result of resource limitations and/or physiological constraints. Such tradeoffs are defined as ...

  Citation × Citation Citation Abstract Copy Title: Effects of Reactive Oxygen Species on Life History Traits of Caenorhabditis elegans Author: Smith, Samson William Year: 2012 Evolutionary life history theory predicts that tradeoffs among fitness-related phenotypes will occur as a result of resource limitations and/or physiological constraints. Such tradeoffs are defined as the cost(s) incurred on one component of fitness (e.g., reproduction) by the increased expression of another fitness-related trait (e.g., longevity). Only recently have researchers begun to investigate the mechanistic bases of life history tradeoffs. A recent proposal is that reactive oxygen species (ROS) have a central role in shaping life history traits and tradeoffs. Research on disparate animal taxa has highlighted strong correlations between oxidative stress resistance and fitness-related life history traits, for example. Here, I use the model organism Caenorhabditis elegans to test several hypotheses concerning the effects of ROS on life history traits and the manifestation of life history tradeoffs. Additionally, I use heat stress and an alternate food source to explore the responses of life history traits to other forms of physiological stress. Relative fitness and other traits related to reproduction were found to be affected in mostly negative ways by increasing oxidative insult. Lifespan was surprisingly unaffected by oxidative stress, but was modified by temperature. In vivo ROS levels as measured by fluorescent microscopy reveal a tradeoff between antioxidant production and reproduction in this species. Title: Effects of Reactive Oxygen Species on Life History Traits of Caenorhabditis elegans Author: Smith, Samson William Year: 2012 Evolutionary life history theory predicts that tradeoffs among fitness-related phenotypes will occur as a result of resource limitations and/or physiological constraints. Such tradeoffs are defined as the cost(s) incurred on one component of fitness (e.g., reproduction) by the increased expression of another fitness-related trait (e.g., longevity). Only recently have researchers begun to investigate the mechanistic bases of life history tradeoffs. A recent proposal is that reactive oxygen species (ROS) have a central role in shaping life history traits and tradeoffs. Research on disparate animal taxa has highlighted strong correlations between oxidative stress resistance and fitness-related life history traits, for example. Here, I use the model organism Caenorhabditis elegans to test several hypotheses concerning the effects of ROS on life history traits and the manifestation of life history tradeoffs. Additionally, I use heat stress and an alternate food source to explore the responses of life history traits to other forms of physiological stress. Relative fitness and other traits related to reproduction were found to be affected in mostly negative ways by increasing oxidative insult. Lifespan was surprisingly unaffected by oxidative stress, but was modified by temperature. In vivo ROS levels as measured by fluorescent microscopy reveal a tradeoff between antioxidant production and reproduction in this species. Close