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• 271. [Article] Interpreting Activation Energies in Digital Image Sensors

  We present a study demonstrating the dependence of apparent activation energies on signal charge in digital image sensors. The data presented in this paper are for a charge-coupled device imager, but the ...

  Citation × Citation Citation Abstract Copy Title: Interpreting Activation Energies in Digital Image Sensors Author: Dunlap, Justin C., Blouke, Morley M., Bodegom, Erik, Widenhorn, Ralf Year: 2015 We present a study demonstrating the dependence of apparent activation energies on signal charge in digital image sensors. The data presented in this paper are for a charge-coupled device imager, but the analysis can be applied to CMOS sensors or generally to any system that shows nonlinearity with respect to time. Activation energies for some pixels are observed to vary between values at about half the bandgap of silicon, when calculated at low signal-charge levels, to values approaching the bandgap when calculated at high signal-charge levels. As such, the traditional method of calculating activation energies using a single exposure time at varying temperatures will result in different activation energies dependent on the exposure time chosen, making it difficult to draw physically meaningful conclusions from its value. Therefore, a method of calculating activation energies using a single signal-charge level is proposed, making it easier to correlate activation energies with impurities. Further, we demonstrate how a model of a pixel with a fixed location impurity in conjunction with a moving depletion edge, due to a changing depletion region size, can lead to this behavior. Title: Interpreting Activation Energies in Digital Image Sensors Author: Dunlap, Justin C., Blouke, Morley M., Bodegom, Erik, Widenhorn, Ralf Year: 2015 We present a study demonstrating the dependence of apparent activation energies on signal charge in digital image sensors. The data presented in this paper are for a charge-coupled device imager, but the analysis can be applied to CMOS sensors or generally to any system that shows nonlinearity with respect to time. Activation energies for some pixels are observed to vary between values at about half the bandgap of silicon, when calculated at low signal-charge levels, to values approaching the bandgap when calculated at high signal-charge levels. As such, the traditional method of calculating activation energies using a single exposure time at varying temperatures will result in different activation energies dependent on the exposure time chosen, making it difficult to draw physically meaningful conclusions from its value. Therefore, a method of calculating activation energies using a single signal-charge level is proposed, making it easier to correlate activation energies with impurities. Further, we demonstrate how a model of a pixel with a fixed location impurity in conjunction with a moving depletion edge, due to a changing depletion region size, can lead to this behavior. Close

• 272. [Article] Laser as a Tool to Study Radiation Effects in CMOS

  Energetic particles from cosmic ray or terrestrial sources can strike sensitive areas of CMOS devices and cause soft errors. Understanding the effects of such interactions is crucial as the device technology ...

  Citation × Citation Citation Abstract Copy Title: Laser as a Tool to Study Radiation Effects in CMOS Author: Ajdari, Bahar Year: 2017 Energetic particles from cosmic ray or terrestrial sources can strike sensitive areas of CMOS devices and cause soft errors. Understanding the effects of such interactions is crucial as the device technology advances, and chip reliability has become more important than ever. Particle accelerator testing has been the standard method to characterize the sensitivity of chips to single event upsets (SEUs). However, because of their costs and availability limitations, other techniques have been explored. Pulsed laser has been a successful tool for characterization of SEU behavior, but to this day, laser has not been recognized as a comparable method to beam testing. In this thesis, I propose a methodology of correlating laser soft error rate (SER) to particle beam gathered data. Additionally, results are presented showing a temperature dependence of SER and the "neighbor effect" phenomenon where due to the close proximity of devices a "weakening effect" in the ON state can be observed. Title: Laser as a Tool to Study Radiation Effects in CMOS Author: Ajdari, Bahar Year: 2017 Energetic particles from cosmic ray or terrestrial sources can strike sensitive areas of CMOS devices and cause soft errors. Understanding the effects of such interactions is crucial as the device technology advances, and chip reliability has become more important than ever. Particle accelerator testing has been the standard method to characterize the sensitivity of chips to single event upsets (SEUs). However, because of their costs and availability limitations, other techniques have been explored. Pulsed laser has been a successful tool for characterization of SEU behavior, but to this day, laser has not been recognized as a comparable method to beam testing. In this thesis, I propose a methodology of correlating laser soft error rate (SER) to particle beam gathered data. Additionally, results are presented showing a temperature dependence of SER and the "neighbor effect" phenomenon where due to the close proximity of devices a "weakening effect" in the ON state can be observed. Close

• 273. [Article] Development of a parametric analysis microcomputer model for evaluating the thermodynamic performance of a reciprocating Brayton cycle engine

  In this thesis, applicable data from research on IC engines have been adapted to PACE engine designs. Data from studies on heat transfer, friction, and pressure losses, in particular, have been used. Certain ...

  Citation × Citation Citation Abstract Copy Title: Development of a parametric analysis microcomputer model for evaluating the thermodynamic performance of a reciprocating Brayton cycle engine Author: White, Thomas J. Year: 1987 In this thesis, applicable data from research on IC engines have been adapted to PACE engine designs. Data from studies on heat transfer, friction, and pressure losses, in particular, have been used. Certain parameters which define operation and design characteristics appear to influence PACE engine performance very strongly. Some of the more critical parameters, notably friction and heat transfer coefficients, must be determined experimentally if accurate model results are to be expected. Pressure ratio, compressor RPM, and maximum combustor temperature, the independent operating parameters, also have a dramatic effect on engine performance. Other design or operating characteristics and working fluid properties are not controlled independently. These are dictated by the engine physical design configuration and operation, ambient conditions, and choice of fuel. Title: Development of a parametric analysis microcomputer model for evaluating the thermodynamic performance of a reciprocating Brayton cycle engine Author: White, Thomas J. Year: 1987 In this thesis, applicable data from research on IC engines have been adapted to PACE engine designs. Data from studies on heat transfer, friction, and pressure losses, in particular, have been used. Certain parameters which define operation and design characteristics appear to influence PACE engine performance very strongly. Some of the more critical parameters, notably friction and heat transfer coefficients, must be determined experimentally if accurate model results are to be expected. Pressure ratio, compressor RPM, and maximum combustor temperature, the independent operating parameters, also have a dramatic effect on engine performance. Other design or operating characteristics and working fluid properties are not controlled independently. These are dictated by the engine physical design configuration and operation, ambient conditions, and choice of fuel. Close

• 274. [Article] Novel Application of Simple Molybdates: Catalytic Hydrolysis of an Organophosphate Neurotoxin Under Mild Aqueous Conditions

  A novel protocol for hydrolyzing phosphonothioate neurotoxins has been developed that uses a readily available, inexpensive and non-toxic molybdate (MoO42−). The target organophosphate is O,S-diethylphenyl ...

  Citation × Citation Citation Abstract Copy Title: Novel Application of Simple Molybdates: Catalytic Hydrolysis of an Organophosphate Neurotoxin Under Mild Aqueous Conditions Author: Kuo, Louis Y., Dill, Kristina M., Shari'ati, Yusef A., Bright, Emily K., McCormick, Theresa Year: 2017 A novel protocol for hydrolyzing phosphonothioate neurotoxins has been developed that uses a readily available, inexpensive and non-toxic molybdate (MoO42−). The target organophosphate is O,S-diethylphenyl phosphonothioate (1), a model compound that has served as an analog of the chemical warfare agent VX. Molybdate-mediated hydrolysis of 1 proceeds at room temperature (pH ∼ 7.5) and yields a relatively safe phosphonate product through P-S specific scission. This is the first report of utilizing the molybdate, MoO42−, to degrade an organophosphate neurotoxin with turnover. A ΔS‡ of −81.5 J/mol·K (−19.5 cal/mol·K) indicates a bimolecular process, and 18O-labeling studies show no oxygen exchange of 1 throughout the hydrolysis by MoO42−(aq). We hypothesize primarily the monomeric molybdate is the active species at pH 7.5 where a SN2(P) mechanism takes place. Density functional theory methods suggest the molybdate oxoanion serves as the nucleophile to attack phosphonothioate 1 to form a molybdate-phosphonate anhydride that subsequently hydrolyzes to the starting molybdate and phenylethyl phosphonate. Title: Novel Application of Simple Molybdates: Catalytic Hydrolysis of an Organophosphate Neurotoxin Under Mild Aqueous Conditions Author: Kuo, Louis Y., Dill, Kristina M., Shari'ati, Yusef A., Bright, Emily K., McCormick, Theresa Year: 2017 A novel protocol for hydrolyzing phosphonothioate neurotoxins has been developed that uses a readily available, inexpensive and non-toxic molybdate (MoO42−). The target organophosphate is O,S-diethylphenyl phosphonothioate (1), a model compound that has served as an analog of the chemical warfare agent VX. Molybdate-mediated hydrolysis of 1 proceeds at room temperature (pH ∼ 7.5) and yields a relatively safe phosphonate product through P-S specific scission. This is the first report of utilizing the molybdate, MoO42−, to degrade an organophosphate neurotoxin with turnover. A ΔS‡ of −81.5 J/mol·K (−19.5 cal/mol·K) indicates a bimolecular process, and 18O-labeling studies show no oxygen exchange of 1 throughout the hydrolysis by MoO42−(aq). We hypothesize primarily the monomeric molybdate is the active species at pH 7.5 where a SN2(P) mechanism takes place. Density functional theory methods suggest the molybdate oxoanion serves as the nucleophile to attack phosphonothioate 1 to form a molybdate-phosphonate anhydride that subsequently hydrolyzes to the starting molybdate and phenylethyl phosphonate. Close

• 275. [Article] Demand Forcasting: Efficacy of Support Vector Machines

  The purpose of this class was to develop an hourly demand forecast for 2017 based on on the previous demand and temperature data of the ISO NE region. There was no specified method to create the model, ...

  Citation × Citation Citation Abstract Copy Title: Demand Forcasting: Efficacy of Support Vector Machines Author: Slay, Tylor Year: 2017 The purpose of this class was to develop an hourly demand forecast for 2017 based on on the previous demand and temperature data of the ISO NE region. There was no specified method to create the model, and the majority of the work was to be done outside of class. The class was supposed to coincide with the Global Energy Forecasting Competition (GefCOM) to drive innovations and competition. However, the class stated weeks into the competition leaving the students behind in both time and understanding. The forecasting method chosen for this report was a Support Vector Machine (SVM) based on the mean hourly demand that factored in various time-series information such as: day-of-month, weekday, week-of-month, and month. The mean demand was chosen to reduce the error introduced by attempting to predict the weather as well as the demand. While the final results for the SVM model were not extraordinary by any means. It was still shown to be an affective tool for time-series forecasting. This report does deviate from the majority of the class due to an error in the registration for the competition. Since this reports forecasts would not be seen by anyone other than in class. Nearly all of the competition deliverables were chosen to be either the previous years demand or it’s mean hourly demand. It was evident that many of the models developed through the term were not good, therefore it seemed reasonable to simple use the previous years data as a place holder until a better model could be developed. Title: Demand Forcasting: Efficacy of Support Vector Machines Author: Slay, Tylor Year: 2017 The purpose of this class was to develop an hourly demand forecast for 2017 based on on the previous demand and temperature data of the ISO NE region. There was no specified method to create the model, and the majority of the work was to be done outside of class. The class was supposed to coincide with the Global Energy Forecasting Competition (GefCOM) to drive innovations and competition. However, the class stated weeks into the competition leaving the students behind in both time and understanding. The forecasting method chosen for this report was a Support Vector Machine (SVM) based on the mean hourly demand that factored in various time-series information such as: day-of-month, weekday, week-of-month, and month. The mean demand was chosen to reduce the error introduced by attempting to predict the weather as well as the demand. While the final results for the SVM model were not extraordinary by any means. It was still shown to be an affective tool for time-series forecasting. This report does deviate from the majority of the class due to an error in the registration for the competition. Since this reports forecasts would not be seen by anyone other than in class. Nearly all of the competition deliverables were chosen to be either the previous years demand or it’s mean hourly demand. It was evident that many of the models developed through the term were not good, therefore it seemed reasonable to simple use the previous years data as a place holder until a better model could be developed. Close

• 276. [Article] CE-QUAL-W2, Version 3

  CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic code supported by the U.S. Army Engineer Research and Development Center (Cole and Buchak 1995). The model has been widely applied to stratified ...

  Citation × Citation Citation Abstract Copy Title: CE-QUAL-W2, Version 3 Author: Wells, Scott A., Cole, Thomas M. Year: 2000 CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic code supported by the U.S. Army Engineer Research and Development Center (Cole and Buchak 1995). The model has been widely applied to stratified surface water systems such as lakes, reservoirs, and estuaries and computes water levels, horizontal and vertical velocities, temperature, and 21 other water quality parameters (such as dissolved oxygen, nutrients, organic matter, algae, pH, the carbonate cycle, bacteria, and dissolved and suspended solids). A typical model grid is shown in Figure 1 where the vertical axis is aligned with gravity. This technical note documents the development of CE-QUAL-W2, Version 3, which incorporates sloping riverine sections. Version 3 has the capability of modeling entire river basins with rivers and interconnected lakes, reservoirs, and/or estuaries. Four example applications illustrate the use of Version 3. Title: CE-QUAL-W2, Version 3 Author: Wells, Scott A., Cole, Thomas M. Year: 2000 CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic code supported by the U.S. Army Engineer Research and Development Center (Cole and Buchak 1995). The model has been widely applied to stratified surface water systems such as lakes, reservoirs, and estuaries and computes water levels, horizontal and vertical velocities, temperature, and 21 other water quality parameters (such as dissolved oxygen, nutrients, organic matter, algae, pH, the carbonate cycle, bacteria, and dissolved and suspended solids). A typical model grid is shown in Figure 1 where the vertical axis is aligned with gravity. This technical note documents the development of CE-QUAL-W2, Version 3, which incorporates sloping riverine sections. Version 3 has the capability of modeling entire river basins with rivers and interconnected lakes, reservoirs, and/or estuaries. Four example applications illustrate the use of Version 3. Close

• 277. [Article] Microscopic formulation of the Zimm-Bragg model for the helix-coil transition

  A microscopic spin model is proposed for the phenomenological Zimm-Bragg model for the helix-coil transition in biopolymers. This model is shown to provide the same thermophysical properties of the original ...

  Citation × Citation Citation Abstract Copy Title: Microscopic formulation of the Zimm-Bragg model for the helix-coil transition Author: Badasyan, A. V., Giacometti, A., Mamasakhlisov, Y. S., Morozov, V. F., Benight, Albert S. Year: 2010 A microscopic spin model is proposed for the phenomenological Zimm-Bragg model for the helix-coil transition in biopolymers. This model is shown to provide the same thermophysical properties of the original Zimm-Bragg model and it allows a very convenient framework to compute statistical quantities. Physical origins of this spin model are made transparent by an exact mapping into a one-dimensional Ising model with an external field. However, the dependence on temperature of the reduced external field turns out to differ from the standard one-dimensional Ising model and hence it gives rise to different thermophysical properties, despite the exact mapping connecting them. We discuss how this point has been frequently overlooked in the recent literature. Title: Microscopic formulation of the Zimm-Bragg model for the helix-coil transition Author: Badasyan, A. V., Giacometti, A., Mamasakhlisov, Y. S., Morozov, V. F., Benight, Albert S. Year: 2010 A microscopic spin model is proposed for the phenomenological Zimm-Bragg model for the helix-coil transition in biopolymers. This model is shown to provide the same thermophysical properties of the original Zimm-Bragg model and it allows a very convenient framework to compute statistical quantities. Physical origins of this spin model are made transparent by an exact mapping into a one-dimensional Ising model with an external field. However, the dependence on temperature of the reduced external field turns out to differ from the standard one-dimensional Ising model and hence it gives rise to different thermophysical properties, despite the exact mapping connecting them. We discuss how this point has been frequently overlooked in the recent literature. Close

• 278. [Article] Existence of High-Order Superlattices in Orientationally Ordered C_{60}

  We correlate the presence or absence of high-order modulated structures in solid C60 with the differential scanning calorimetry signature of the orientational ordering transition and other diagnostic data. ...

  Citation × Citation Citation Abstract Copy Title: Existence of High-Order Superlattices in Orientationally Ordered C_{60} Author: Fischer, J. E., Luzzi, D. E., Kniaź, K., McGhie, A. R., Ricketts-Foot, D. A., Romanow, W. R., Vaughan, Gavin B. M., Li, Dayin, Smith, Allan L., Strongin, Robert M., Cichy, M. A., Bard, Laurent, Smith, Amos B., III Year: 1993 We correlate the presence or absence of high-order modulated structures in solid C60 with the differential scanning calorimetry signature of the orientational ordering transition and other diagnostic data. We have searched for, but not observed, the 2a face-centered cubic structure recently observed in low-temperature electron and single-crystal x-ray diffraction. We conclude that the intrinsic ground state is the previously reported simple cubic structure [space groupPa3¯, a(14 K)=14.06 Å], and that other structures may be stabilized by defects or impurities. Title: Existence of High-Order Superlattices in Orientationally Ordered C_{60} Author: Fischer, J. E., Luzzi, D. E., Kniaź, K., McGhie, A. R., Ricketts-Foot, D. A., Romanow, W. R., Vaughan, Gavin B. M., Li, Dayin, Smith, Allan L., Strongin, Robert M., Cichy, M. A., Bard, Laurent, Smith, Amos B., III Year: 1993 We correlate the presence or absence of high-order modulated structures in solid C60 with the differential scanning calorimetry signature of the orientational ordering transition and other diagnostic data. We have searched for, but not observed, the 2a face-centered cubic structure recently observed in low-temperature electron and single-crystal x-ray diffraction. We conclude that the intrinsic ground state is the previously reported simple cubic structure [space groupPa3¯, a(14 K)=14.06 Å], and that other structures may be stabilized by defects or impurities. Close

• 279. [Article] Unusual Thermal Stability of a Site-Ordered MC60 Rocksalt Structure (M=K, Rb, or Cs).

  X-ray diffraction and differential scanning calorimetry of MxC60, with x∼1 and M=K, Rb, or Cs, reveal an unusual T-dependent phase sequence. A low-symmetry ground state is found, while the high-T limit ...

  Citation × Citation Citation Abstract Copy Title: Unusual Thermal Stability of a Site-Ordered MC60 Rocksalt Structure (M=K, Rb, or Cs). Author: Zhu, Q., Zhou, O., Fischer, J. E., McGhie, Andrew R., Romanow, W. R., Strongin, Robert M., Cichy, M. A., Smith, Amos B., III Year: 1993 X-ray diffraction and differential scanning calorimetry of MxC60, with x∼1 and M=K, Rb, or Cs, reveal an unusual T-dependent phase sequence. A low-symmetry ground state is found, while the high-T limit is an ordered rocksalt structure in which only the octahedral sites are occupied. The unusual high-T stability of this ordered phase is attributed to the entropy of molecular orientational disorder and/or thermal disorder of the alkali-metal ions within the octahedral sites. Unique to KxC60 with x≥1.4, we find at intermediate temperatures an fcc site-disordered lattice gas phase with random occupancy of tetrahedral and octahedral sites, which is thus isostructural with superconducting K3C60. Title: Unusual Thermal Stability of a Site-Ordered MC60 Rocksalt Structure (M=K, Rb, or Cs). Author: Zhu, Q., Zhou, O., Fischer, J. E., McGhie, Andrew R., Romanow, W. R., Strongin, Robert M., Cichy, M. A., Smith, Amos B., III Year: 1993 X-ray diffraction and differential scanning calorimetry of MxC60, with x∼1 and M=K, Rb, or Cs, reveal an unusual T-dependent phase sequence. A low-symmetry ground state is found, while the high-T limit is an ordered rocksalt structure in which only the octahedral sites are occupied. The unusual high-T stability of this ordered phase is attributed to the entropy of molecular orientational disorder and/or thermal disorder of the alkali-metal ions within the octahedral sites. Unique to KxC60 with x≥1.4, we find at intermediate temperatures an fcc site-disordered lattice gas phase with random occupancy of tetrahedral and octahedral sites, which is thus isostructural with superconducting K3C60. Close

• 280. [Article] Structure and Phase Transition of the 6,5-Annulene Isomer of C_{61}H_{2}

  We have used differential scanning calorimetry and x-ray diffraction to study the crystalline phases of the 6,5-annulene isomer of C61H2. At 308 K the methylenated fullerenes are orientationally disordered ...

  Citation × Citation Citation Abstract Copy Title: Structure and Phase Transition of the 6,5-Annulene Isomer of C_{61}H_{2} Author: Lommen, Andrea N., Heiney, Paul A., Vaughan, Gavin B. M., Stephens, Peter W., Liu, Dengfa, Li, Dayin, Smith, Allan L., McGhie, Andrew R., Strongin, Robert M., Brard, Laurent, Smith, Amos B., III Year: 1994 We have used differential scanning calorimetry and x-ray diffraction to study the crystalline phases of the 6,5-annulene isomer of C61H2. At 308 K the methylenated fullerenes are orientationally disordered in a face-centered cubic lattice with lattice parameter 14.19±0.02 Å. Below Tc=290 K the symmetry is lowered to Pa3¯, a simple-cubic structure. At 20 K the lattice parameter is 14.06±0.02 Å, with substantial statistical disorder remaining. The transition temperature in C61H2 is slightly higher than in C60O and higher still than in C60, but the three compounds exhibit orientationally ordering transitions between qualitatively similar phases. Title: Structure and Phase Transition of the 6,5-Annulene Isomer of C_{61}H_{2} Author: Lommen, Andrea N., Heiney, Paul A., Vaughan, Gavin B. M., Stephens, Peter W., Liu, Dengfa, Li, Dayin, Smith, Allan L., McGhie, Andrew R., Strongin, Robert M., Brard, Laurent, Smith, Amos B., III Year: 1994 We have used differential scanning calorimetry and x-ray diffraction to study the crystalline phases of the 6,5-annulene isomer of C61H2. At 308 K the methylenated fullerenes are orientationally disordered in a face-centered cubic lattice with lattice parameter 14.19±0.02 Å. Below Tc=290 K the symmetry is lowered to Pa3¯, a simple-cubic structure. At 20 K the lattice parameter is 14.06±0.02 Å, with substantial statistical disorder remaining. The transition temperature in C61H2 is slightly higher than in C60O and higher still than in C60, but the three compounds exhibit orientationally ordering transitions between qualitatively similar phases. Close