Physics Commons^™

Revisiting Hafemeister’S ‘Science And Society’ Tests, Robert Brecha, Rex Berney, Bruce Craver

Robert J. Brecha

We revisit a series of papers on science and society issues by David Hafemeister in the 1970s and 1980s. The emphasis in the present work is on world oil production limits and some consequences of various possible scenarios for the near future. Some of the data and scenarios used by Hafemeister are updated for U.S. oil production in the past two decades and extended to an analysis of a peak in world oil production in the future. We discuss some simple scenarios for future energy use patterns and look at the consequence of these scenarios as world oil production begins …

Emissions Scenarios In The Face Of Fossil-Fuel Peaking, Robert Brecha

Robert J. Brecha

Emissions scenarios used by the Intergovernmental Panel on Climate Change (IPCC) are based on detailed energy system models in which demographics, technology and economics are used to generate projections of future world energy consumption, and therefore, of greenhouse gas emissions. We propose in this paper that it is useful to look at a qualitative model of the energy system, backed by data from short- and medium-term trends, to gain a sense of carbon emission bounds. Here we look at what may be considered a lower bound for 21st century emissions given two assumptions: first, that extractable fossil-fuel resources follow the …

Bose-Einstein Condensation Of Potassium Atoms By Sympathetic Cooling, Giovanni Modugno, Gabriele Ferrari, Giacomo Roati, Robert Brecha, A. Simoni, Massimo Inguscio

Robert J. Brecha

We report on the Bose-Einstein condensation of potassium atoms, whereby quantum degeneracy is achieved by sympathetic cooling with evaporatively cooled rubidium. Because of the rapid thermalization of the two different atoms, the efficiency of the cooling process is high. The ability to achieve condensation by sympathetic cooling with a different species may provide a route to the production of degenerate systems with a larger choice of components.

Collapse Of A Degenerate Fermi Gas, Giovanni Modugno, Giacomo Roati, Francesco Riboli, Francesca Ferlaino, Robert Brecha, Massimo Inguscio

Robert J. Brecha

A degenerate gas of identical fermions is brought to collapse by the interaction with a Bose-Einstein condensate. We used an atomic mixture of fermionic potassium-40 and bosonic rubidium-87, in which the strong interspecies attraction leads to an instability above a critical number of particles. The observed phenomenon suggests a direction for manipulating fermion-fermion interactions on the route to superfluidity.

Cost Optimization With Solar And Conventional Energy Production, Energy Storage, And Real Time Pricing, Ata Raziei, Kevin Hallinan, Robert Brecha

Robert J. Brecha

Research is presented that investigates the potential for solar power generation with battery energy storage for reducing the effective cost of energy delivered to residential customers if real time pricing is present. A linear optimization approach is developed based upon a two-step process. In step one, given a specified solar array area and battery capacity, the optimal means to meet loads based upon grid power, solar power, and/or battery power is determined. This analysis considers an expected lifespan of the solar panel. With these results established, in the next step, the capital costs for the solar arrays and batteries are …

Dipolar Oscillations In A Quantum Degenerate Fermi–Bose Atomic Mixture, Francesca Ferlaino, Robert Brecha, Peter Hannaford, Francesco Riboli, Giacomo Roati, Giovanni Modugno, Massimo Inguscio

Robert J. Brecha

We study the dynamics of coupled dipolar oscillations in a Fermi–Bose mixture of 40K and 87Rb atoms. This low-energy collective mode is strongly affected by the interspecies interactions. Measurements are performed in the classical and quantum degenerate regimes and reveal the crucial role of the statistical properties of the mixture. At the onset of quantum degeneracy, we investigate the role of Pauli blocking and superfluidity for K and Rb atoms, respectively, resulting in a change in the collisional interactions.

The Carbon Rent Economics Of Climate Policy, Matthias Kalkuhl, Robert Brecha

Robert J. Brecha

By reducing the demand for fossil fuels, climate policy can reduce scarcity rents for fossil resource owners. As mitigation policies ultimately aim to limit emissions, a new scarcity for “space” in the atmosphere to deposit emissions is created. The associated scarcity rent, or climate rent (that is, for example, directly visible in permit prices under an emission trading scheme) can be higher or lower than the original fossil resource rent. In this paper, we analyze analytically and numerically the impact of mitigation targets, resource availability, backstop costs, discount rates and demand parameters on fossil resource rents and the climate rent. …

Analyzing Major Challenges Of Wind And Solar Variability In Power Systems, Falko Ueckerdt, Robert Brecha, Gunnar Luderer

Robert J. Brecha

Ambitious policy targets together with current and projected high growth rates indicate that future power systems will likely show substantially increased generation from renewable energy sources. A large share will come from the variable renewable energy (VRE) sources wind and solar photovoltaics (PV); however, integrating wind and solar causes challenges for existing power systems. In this paper we analyze three major integration challenges related to the structural matching of demand with the supply of wind and solar power: low capacity credit, reduced utilization of dispatchable plants, and over-produced generation. Based on residual load duration curves we define corresponding challenge variables …

Global Fossil Energy Markets And Climate Change Mitigation: An Analysis With Remind, Nico Bauer, Ioanna Mouratiadou, Gunnar Luderer, Lavinia Baumstark, Robert Brecha, Ottmar Edenhofer, Elmar Kriegler

Robert J. Brecha

We analyze the dynamics of global fossil resource markets under different assumptions for the supply of fossil fuel resources, development pathways for energy demand, and climate policy settings. Resource markets, in particular the oil market, are characterized by a large discrepancy between costs of resource extraction and commodity prices on international markets. We explain this observation in terms of (a) the intertemporal scarcity rent, (b) regional price differentials arising from trade and transport costs, (c) heterogeneity and inertia in the extraction sector. These effects are captured by the REMIND model. We use the model to explore economic effects of changes …

Logistic Curves, Extraction Costs And Peak Oil, Robert Brecha

Robert J. Brecha

Debates about the possibility of a near-term maximum in world oil production have become increasingly prominent over the past decade, with the focus often being on the quantification of geologically available and technologically recoverable amounts of oil in the ground. Economically, the important parameter is not a physical limit to resources in the ground, but whether market price signals and costs of extraction will indicate the efficiency of extracting conventional or nonconventional resources as opposed to making substitutions over time for other fuels and technologies. We present a hybrid approach to the peak-oil question with two models in which the …

Economic And Environmental Impacts Of Community-Based Residential Building Energy Efficiency Investment, Jun-Ki Choi, Drew Morrison, Kevin Hallinan, Robert Brecha

Robert J. Brecha

A systematic framework for evaluating the local economic and environmental impacts of investment in building energy efficiency is developed. Historical residential building energy data, community-wide economic input-output data, and emission intensity data are utilized. The aim of this study is to show the comprehensive insights and connection among achieving variable target reductions for a residential building energy use, economic and environmental impacts. Central to this approach for the building energy reduction goal is the creation of individual energy models for each building based upon historical energy data and available building data. From these models, savings estimates and cost implications can …

Cost-Availability Curves For Hierarchical Implementation Of Residential Energy-Efficiency Measures, Roman Villoria-Siegert, Philip Brodrick, Kevin Hallinan, Robert Brecha

Robert J. Brecha

Historical residential electricity data and natural gas consumption data were collected for, respectively, 1,200 and 178 residences in a small town in the USA. These data were merged with local building and weather databases, and energy consumption models were developed for each residence, revealing substantial variation in heating and cooling intensity. After estimating approximate physical building characteristics, energy profiles for each residence were calculated, and savings from adoption of the most cost-effective energy-efficiency measures for each residence were estimated. Effectively, we wish to leverage commonly available data sets to infer characteristics of building envelopes and equipment, without the need for …

Development Without Energy? Assessing Future Scenarios Of Energy Consumption In Developing Countries, Jan Steckel, Robert Brecha, Michael Jakob, Jessica Strefler, Gunnar Luderer

Robert J. Brecha

We analyze the relationship between economic development and energy consumption in the context of greenhouse gas mitigation. The main contribution of this work is to compare estimates of energy thresholds in the form of minimum energy requirements to reach high levels of development with output projections of per capita final energy supply from a group of integrated assessment models (IAMs). Scenarios project that reductions of carbon emissions in developing countries will be achieved not only by means of decreasing the carbon intensity, but also by making a significant break with the historically observed relationship between energy use and economic growth. …

Video Feature — Banned Books And The Stuart Rose Collection, Robert Brecha, Una Cadegan, John Inglis, Paul Morman

Robert J. Brecha

A faculty panel discussion in two sessions:

Session 1:
The Index: Una Cadegan (history) looks at the current scholarship on the Index of Forbidden Books.
Galileo: Robert Brecha (physics) highlights the banning of Galileo and observational science.

Session 2:
Thomas Aquinas: John Inglis (philosophy) speaks on the banning of Thomas Aquinas's Summa Theologica, the most important book in Catholic intellectual tradition.
Descartes and the Index of Forbidden Books: Paul Morman (history, Distinguished Service Professor) highlights the book by Descartes that he was not allowed to study while a student at UD in the 1960s.

Synthesis, Crystal Structure And Thermoelectric Properties Of Β-K2bi8se13 Solid Solutions, Theodora Kyratsi, Duck-Young Chung, Jeff Dyck, Ctirad Uher, Sangeeta Lal, Sim Loo, Tim Hogan, John Ireland, Carl Kannewurf, Evripides Hatzikraniotis, Konstantinos Paraskevopoulos, Mercouri Kanatzidis

Jeffrey Dyck

Solid solution series of the type K2Bi8-xSbxSe13, K2-xRbxBi8Se13 as well as K2Bi8Se13-xSx were prepared and the distribution of the atoms (Bi/Sb, K/Rb and Se/S) on different crystallographic sites, the band gaps and their thermoelectric properties were studied. The distribution Se/S appears to be more uniform than the distribution of the Sb and Rb atoms in the β-K2Bi8Se13 structure that shows preference in specific sites in the lattice. Band gap is mainly affected by Sb and S substitution. Seebeck coefficient measurements showed n-type character for of all Se/S members. In the Bi/Sb series an enhancement of p-type character was observed. The …

Growth Of Oriented Thick Films Of Gallium Nitride From The Melt., Jeffrey Dyck, K. Kash, M. Grossner, C. Hayman, A. Argoitia, N. Yang, M.-H. Hong, M. Kordesch, J. Angus

Jeffrey Dyck

While significant strides have been made in the optimization of GaN-based devices on foreign substrates, a more attractive alternative would be homoepitaxy on GaN substrates. The primary motivation of this work is to explore the growth of thick films of GaN from the melt for the ultimate use as substrate material. We have previously demonstrated the synthesis of polycrystalline, wurtzitic gallium nitride and indium nitride by saturating gallium metal and indium metal with atomic nitrogen from a microwave plasma source. Plasma synthesis avoids the high equilibrium pressures required when molecular nitrogen is used as the nitrogen source. Here we report …

Characteriation Of Bulk, Polycrystalline Indium Nitride Grown Of Subatmospheric Pressures, Jeffrey Dyck, Kathleen Kash, Kwieseon Kim, Walter Lambrecht, Cliff Hayman, Alberto Argoitia, Michael Grossner, Willie Zhou, John Angus

Jeffrey Dyck

Polycrystalline, wurtzitic indium nitride was synthesized by saturating indium metal with atomic nitrogen from a microwave plasma source. Plasma synthesis avoids the high equilibrium pressures required when molecular nitrogen is used as the nitrogen source. Two types of growth were observed: 1) small amounts of indium nitride crystallized from the melt during cooling and 2) hexagonal platelets formed adjacent to the In metal source on the crucible sides. The mechanism of this latter growth is not established, but may involve transport of indium as a liquid film. The crystals were characterized by electron diffraction, X-ray diffraction, elemental analysis, scanning electron …

Synthesis Of Bulk, Polycrystalline Gallium Nitride At Low Pressures, Alberto Argoitia, John Angus, Cliff Hayman, Long Wang, Jeffrey Dyck, Kathleen Kash

Jeffrey Dyck

Bulk, polycrytalline gallium nitride was crystallized from gallium saturated with nitrogen obtained from a microwave electron cyclotron resonance source. The polycrystalline samples are wurtzitic and n-type. Well-faceted crystals give near-band-edge and yellow band photo-luminescence at both 10K and 300K. The results show that atomic nitrogen is an attractive alternative to high pressure molecular nitrogen for saturation of gallium with nitrogen for synthesis of bulk gallium nitride.

Growth Of Bulk, Polycrystalline Gallium And Indium Nitride At Sub-Atmospheric Pressures, John Angus, Alberto Argoitia, Cliff Hayman, Long Wang, Jeffrey Dyck, Kathleen Kash

Jeffrey Dyck

Bulk polycrystalline gallium nitride and indium nitride were crystallized at sub-atmospheric pressures by saturating the pure metals with nitrogen from a microwave electron cyclotron resonance source. Saturation of Ga/In melts with nitrogen led only to the crystallization of gallium nitride. The polycrystralline samples were wurtzitic. The gallium nitride was well faceted, with narrow Raman lineshapes, and showed near-band-edge and yellow band photo-luminescence at both 4K and 300K. The indium nitirde was formed in smaller amounts, was less well faceted, and showed no photoluminescence.