Ryan Tanner - Academia.edu (original) (raw)

Papers by Ryan Tanner

As systems in high performance buildings become more complex and manually operable windows and sh... more As systems in high performance buildings become more complex and manually operable windows and shading devices are incorporated into advanced buildings, it is imperative that building engineers understand and account for the impacts that occupant behavior may have on building performance. By coupling building energy simulation models with stochastic occupant behavior models, the magnitude and distribution of impacts that occupants have on building energy consumption are demonstrated via a simulation study. The results show that occupant actions can increase or decrease energy consumption depending on the HVAC control strategy implemented. For a single month during the cooling season, the range of HVAC electricity consumption predicted by a set of simulations that included stochastic models of occupant window, blind, and lighting use varied by approximately 20% for each of 25 different control scenarios.

In an attempt to increase energy efficiency in high-performance mixed-mode buildings, a control o... more In an attempt to increase energy efficiency in high-performance mixed-mode buildings, a control optimization is conducted, yielding a sequence of best-case energy saving and comfort preserving window opening schedules. The optimal sequence and a set of corresponding predictors are used in a classification tree analysis to glean simple control logic from the optimal solution that can be embedded in a building control system. Due to a comfort-heavy weighted objective function, the optimal control sequence is shown to perform worse than a default control sequence for the example building, however the extracted control rule performs as well as, and in some cases better than the default, improving comfort with no added energy cost.

The Astrophysical Journal

Galactic winds are associated with intense star formation and AGNs. Depending on their formation ... more Galactic winds are associated with intense star formation and AGNs. Depending on their formation mechanism and velocity they may remove a significant fraction of gas from their host galaxies, thus suppressing star formation, enriching the intergalactic medium, and shaping the circumgalactic gas. However, the long-term evolution of these winds remains mostly unknown. We report the detection of a wind from NGC 3079 to at least 60 kpc from the galaxy. We detect the wind in FUV line emission to 60 kpc (as inferred from the broad FUV filter in GALEX) and in X-rays to at least 30 kpc. The morphology, luminosities, temperatures, and densities indicate that the emission comes from shocked material, and the O/Fe ratio implies that the X-ray emitting gas is enriched by Type II supernovae. If so, the speed inferred from simple shock models is about 500 km s −1 , which is sufficient to escape the galaxy. However, the inferred kinetic energy in the wind from visible components is substantially smaller than canonical hot superwind models.

The Astrophysical Journal

Alberta Law Review

This essay considers sources of opposition to allowing access to medical assistance in dying for ... more This essay considers sources of opposition to allowing access to medical assistance in dying for individuals with mental illness. It originated with an observation by members of the University of Toronto Joint Centre for Bioethics that in mainstream Canadian culture—as well as in political, academic, and professional circles—such opposition remains widespread (and often reflexive) even in light of broad support for access to assisted dying for individuals with illness manifesting in physical suffering. Most Canadians treat the prospect of assisted dying for those with mental illness with suspicion, and it is worth exploring why this opposition persists, what arguments can be leveled to support it, and whether those arguments can be sustained. To that end, I identify five sources of opposition to assisted dying for the mentally ill that seem to characterize the public debate, and argue that none succeed. They either rely on false premises or otherwise fail to secure the conclusion th...

The Astrophysical Journal

Using synthetic absorption lines generated from 3D hydro-dynamical simulations we explore how the... more Using synthetic absorption lines generated from 3D hydro-dynamical simulations we explore how the velocity of a starburst-driven galactic wind correlates with the star formation rate (SFR) and SFR density. We find strong correlations until the scaling relations flatten abruptly at a point set by the mass loading of the starburst. Below this point the scaling relation depends on the temperature regime being probed by the absorption line, not on the mass loading. The exact scaling relation depends on whether the maximum or mean velocity of the absorption line is used. We find that the outflow velocity of neutral gas is four to five times lower than the average velocity of the hottest gas, the difference increasing with gas ionization. Thus, absorption lines of neutral or low ionized gas will underestimate the outflow velocity of hot gas, severely underestimating outflow energetics.

The Astrophysical Journal, 2016

Our three-dimensional hydro-dynamical simulations of starbursts examine the formation of superbub... more Our three-dimensional hydro-dynamical simulations of starbursts examine the formation of superbubbles over a range of driving luminosities and mass loadings that determine superbubble growth and wind velocity. From this we determine the relationship between the velocity of a galactic wind and the power of the starburst. We find a threshold for the formation of a wind, above which the speed of the wind is not affected by grid resolution or the temperature floor of our radiative cooling. We investigate the effect two different temperature floors in our radiative cooling prescription have on wind kinematics and content. We find that cooling to 10 K instead of to 10 4 K increases the mass fraction of cold neutral and hot X-ray gas in the galactic wind while halving that in warm Hα. Our simulations show the mass of cold gas transported into the lower halo does not depend on the starburst strength. Optically bright filaments form at the edge of merging superbubbles, or where a cold dense cloud has been disrupted by the wind. Filaments formed by merging superbubbles will persist and grow to > 400 pc in length if anchored to a star forming complex. Filaments embedded in the hot galactic wind contain warm and cold gas that moves 300 − 1200 km s −1 slower than the surrounding wind, with the coldest gas hardly moving with respect to the galaxy. Warm and cold matter in the galactic wind show asymmetric absorption profiles consistent with observations, with a thin tail up to the wind velocity.

Aps Four Corners Section Meeting Abstracts, Oct 1, 2007

Recently there has been some interest in relativistic models of galaxies which may give some corr... more Recently there has been some interest in relativistic models of galaxies which may give some correction to estimates of how much dark matter is present in a galaxy. There have been claims that the extent of the correction given by general relativity can remove the need to include ...

As systems in high performance buildings become more complex and manually operable windows and sh... more As systems in high performance buildings become more complex and manually operable windows and shading devices are incorporated into advanced buildings, it is imperative that building engineers understand and account for the impacts that occupant behavior may have on building performance. By coupling building energy simulation models with stochastic occupant behavior models, the magnitude and distribution of impacts that occupants have on building energy consumption are demonstrated via a simulation study. The results show that occupant actions can increase or decrease energy consumption depending on the HVAC control strategy implemented. For a single month during the cooling season, the range of HVAC electricity consumption predicted by a set of simulations that included stochastic models of occupant window, blind, and lighting use varied by approximately 20% for each of 25 different control scenarios.

In an attempt to increase energy efficiency in high-performance mixed-mode buildings, a control o... more In an attempt to increase energy efficiency in high-performance mixed-mode buildings, a control optimization is conducted, yielding a sequence of best-case energy saving and comfort preserving window opening schedules. The optimal sequence and a set of corresponding predictors are used in a classification tree analysis to glean simple control logic from the optimal solution that can be embedded in a building control system. Due to a comfort-heavy weighted objective function, the optimal control sequence is shown to perform worse than a default control sequence for the example building, however the extracted control rule performs as well as, and in some cases better than the default, improving comfort with no added energy cost.

The Astrophysical Journal

Galactic winds are associated with intense star formation and AGNs. Depending on their formation ... more Galactic winds are associated with intense star formation and AGNs. Depending on their formation mechanism and velocity they may remove a significant fraction of gas from their host galaxies, thus suppressing star formation, enriching the intergalactic medium, and shaping the circumgalactic gas. However, the long-term evolution of these winds remains mostly unknown. We report the detection of a wind from NGC 3079 to at least 60 kpc from the galaxy. We detect the wind in FUV line emission to 60 kpc (as inferred from the broad FUV filter in GALEX) and in X-rays to at least 30 kpc. The morphology, luminosities, temperatures, and densities indicate that the emission comes from shocked material, and the O/Fe ratio implies that the X-ray emitting gas is enriched by Type II supernovae. If so, the speed inferred from simple shock models is about 500 km s −1 , which is sufficient to escape the galaxy. However, the inferred kinetic energy in the wind from visible components is substantially smaller than canonical hot superwind models.

The Astrophysical Journal

Alberta Law Review

This essay considers sources of opposition to allowing access to medical assistance in dying for ... more This essay considers sources of opposition to allowing access to medical assistance in dying for individuals with mental illness. It originated with an observation by members of the University of Toronto Joint Centre for Bioethics that in mainstream Canadian culture—as well as in political, academic, and professional circles—such opposition remains widespread (and often reflexive) even in light of broad support for access to assisted dying for individuals with illness manifesting in physical suffering. Most Canadians treat the prospect of assisted dying for those with mental illness with suspicion, and it is worth exploring why this opposition persists, what arguments can be leveled to support it, and whether those arguments can be sustained. To that end, I identify five sources of opposition to assisted dying for the mentally ill that seem to characterize the public debate, and argue that none succeed. They either rely on false premises or otherwise fail to secure the conclusion th...

The Astrophysical Journal

Using synthetic absorption lines generated from 3D hydro-dynamical simulations we explore how the... more Using synthetic absorption lines generated from 3D hydro-dynamical simulations we explore how the velocity of a starburst-driven galactic wind correlates with the star formation rate (SFR) and SFR density. We find strong correlations until the scaling relations flatten abruptly at a point set by the mass loading of the starburst. Below this point the scaling relation depends on the temperature regime being probed by the absorption line, not on the mass loading. The exact scaling relation depends on whether the maximum or mean velocity of the absorption line is used. We find that the outflow velocity of neutral gas is four to five times lower than the average velocity of the hottest gas, the difference increasing with gas ionization. Thus, absorption lines of neutral or low ionized gas will underestimate the outflow velocity of hot gas, severely underestimating outflow energetics.

The Astrophysical Journal, 2016

Our three-dimensional hydro-dynamical simulations of starbursts examine the formation of superbub... more Our three-dimensional hydro-dynamical simulations of starbursts examine the formation of superbubbles over a range of driving luminosities and mass loadings that determine superbubble growth and wind velocity. From this we determine the relationship between the velocity of a galactic wind and the power of the starburst. We find a threshold for the formation of a wind, above which the speed of the wind is not affected by grid resolution or the temperature floor of our radiative cooling. We investigate the effect two different temperature floors in our radiative cooling prescription have on wind kinematics and content. We find that cooling to 10 K instead of to 10 4 K increases the mass fraction of cold neutral and hot X-ray gas in the galactic wind while halving that in warm Hα. Our simulations show the mass of cold gas transported into the lower halo does not depend on the starburst strength. Optically bright filaments form at the edge of merging superbubbles, or where a cold dense cloud has been disrupted by the wind. Filaments formed by merging superbubbles will persist and grow to > 400 pc in length if anchored to a star forming complex. Filaments embedded in the hot galactic wind contain warm and cold gas that moves 300 − 1200 km s −1 slower than the surrounding wind, with the coldest gas hardly moving with respect to the galaxy. Warm and cold matter in the galactic wind show asymmetric absorption profiles consistent with observations, with a thin tail up to the wind velocity.

Aps Four Corners Section Meeting Abstracts, Oct 1, 2007

Recently there has been some interest in relativistic models of galaxies which may give some corr... more Recently there has been some interest in relativistic models of galaxies which may give some correction to estimates of how much dark matter is present in a galaxy. There have been claims that the extent of the correction given by general relativity can remove the need to include ...