Physical Sciences and Mathematics Commons^™

Cooperation Targets: From Industry To Energy Services, Stephanie Ohshita, A Meier, S Wiel, G Heggelund

Environmental Science

Our research has identified three key trends in existing energy efficiency cooperation. The first, discussed in Chapter 3, is the growing role of independent, international cooperation networks in facilitating large-scale energy efficiency improvements. The second, explored in Chapter 4, is the increasing importance of policy development cooperation as an effective mechanism for promoting significant energy savings and greenhouse gas reductions. In Chapter 5, we examine cooperation activity sector by sector and note increasing activity in certain economic sectors with numerous, diverse actors, most notably in appliances, transportation and buildings. In the industrial sector, there is a trend from “hard” technology …

Effects Of Economic And Environmental Reform On The Diffusion Of Cleaner Coal Technology In China, Stephanie Ohshita, L Ortolano

Environmental Science

Coal is both the major fuel for China's economic development and the major source of its severe air pollution. China's reliance on coal for nearly three-quarters of its primary energy has contributed to local air pollution, regional acid rain and global climate change. At the same time, the country's coal consumption has electrified its growing cities and helped Chinese steel and chemical industries to become international powerhouses.

This contribution considers how the intertwined issues of environmental reform and economic reform have affected efforts to reduce coal-related air pollution in China. Our analysis focuses on government efforts to promote the diffusion …

Spectroscopic Characterization Of The Ground And Low-Lying Electronic States Of Ga2n Via Anion Photoelectron Spectroscopy., S M. Sheehan, Giovanni Meloni, B F. Parsons, N Wehres, D M. Neumark

Chemistry Faculty Publications

Anion photoelectron spectra of Ga2N− were measured at photodetachment wavelengths of 416nm(2.978eV), 355nm(3.493eV), and 266nm(4.661eV). Both field-free time-of-flight and velocity-map imaging methods were used to collect the data. The field-free time-of-flight data provided better resolution of the features, while the velocity-map-imaging data provided more accurate anisotropy parameters for the peaks. Transitions from the ground electronic state of the anion to two electronic states of the neutral were observed and analyzed with the aid of electronic structure calculations and Franck-Condon simulations. The ground-state band was assigned to a transition between linear ground states of Ga2N−(XΣg+1) and Ga2N(XΣu+2), yielding the electron affinity …

Optical Decoherence And Spectral Diffusion At 1.5 Μm In Er3+: Y2 Sio5 Versus Magnetic Field, Temperature, And Er3+ Concentration, Thomas Böttger, C W. Thiel, Y Sun, R L. Cone

Physics and Astronomy

The mechanisms and effects of spectral diffusion for optical transitions of paramagnetic ions have been explored using the inhomogeneously broadened 1536 nm I15∕24→I13∕24 transition in Er3+:Y2SiO5. Using photon echo spectroscopy, spectral diffusion was measured by observing the evolution of the effective coherence lifetimes over time scales from 1μs to 20 ms for magnetic-field strengths from 0.3 to 6.0 T, temperatures from 1.6 to 6.5 K, and nominal Er3+ concentrations of 0.0015%, 0.005%, and 0.02%. To understand the effect of spectral diffusion on material decoherence for different environmental conditions and material compositions, data and models were compared to identify spectral diffusion …

Spectroscopy And Dynamics Of Er3+: Y2 Si O5 At 1.5 Μm, Thomas Böttger, Y Sun, C W. Thiel, R L. Cone

Physics and Astronomy

We present the results of detailed site-selective spectroscopy performed on the I15∕24↔I13∕24 transition of Er3+:Y2SiO5 at 1.5μm. New determinations of the I13∕24 and I15∕24 crystal-field-level structure for the two crystallographically inequivalent Er3+ sites have been made. The fluorescence dynamics of the metastable I13∕24:Y1 excited state was investigated, showing exponential decays for Er3+ at both crystallographic sites with fluorescence lifetimes of 11.4ms for site 1 and 9.2ms for site 2. Exceptionally sharp inhomogeneous absorption lines of 180, 390, and 510MHz were observed in 0.0015% Er3+:Y2SiO5, 0.005% Er3+:Y2SiO5, and 0.02% Er3+:Y2SiO5 crystals, respectively. The g-values for the lowest energy I15∕24 (Z1) and …

A Cosmic Milestone: Constraints From Metal-Poor Halo Stars On The Cosmological Reionization Epoch, Aparna Venkatesan

Physics and Astronomy

Theoretical studies and current observations of the high-redshift intergalactic medium (IGM) indicate that at least two cosmic transitions occur by the time the universe reaches gas metallicities of about 10^-3 Z_☉. One is the cosmological reionization of the IGM, and the second is the transition from a primordial to present-day mode of star formation. We quantify this relation through new calculations of the ionizing radiation produced in association with the elements carbon, oxygen, and silicon observed in Galactic metal-poor halo stars, which are likely second-generation objects formed in the wake of primordial supernovae. We demonstrate that sufficient …

Effects Of Aphid (Homoptera) Abundance And Surrounding Vegetation On The Encounter Rate Of Coccinellidae (Coleoptera), Chrysopidae (Neuroptera) And Nabidae (Hemiptera) In Alfalfa., James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

A Convective Line With Leading Stratiform Precipitation From Bamex, Brandom Storm, Matthew D. Parker, David P. Jorgensen

School of Natural Resources: Faculty Publications

On 31 May 2003, a front-fed convective line with leading stratiform precipitation (FFLS) was observed during the Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX). The high-resolution BAMEX measurements provided one of the first opportunities to thoroughly observe the characteristics of an FFLS system. The 31 May system had an overturning updraft during its early stages, and produced leading stratiform precipitation. As the system matured, a jump updraft developed and the system began to produce trailing stratiform precipitation. It appears that this transition was facilitated by a local decrease in the low-level line-perpendicular vertical wind shear over time, as well …

Severe Convective Wind Environments, Evan L. Kuchera, Matthew D. Parker

School of Natural Resources: Faculty Publications

Nontornadic thunderstorm winds from long-lived, widespread convective windstorms can have a tremendous impact on human lives and property. To examine environments that support damaging wind producing convection, sounding parameters from Rapid Update Cycle model analyses (at 3-hourly intervals) from 2003 were compared with 7055 reports of damaging winds and 377 081 occurrences of lightning. Ground- relative wind velocity was the most effective at discriminating between damaging and nondamaging wind convective environments. Steep surface-based lapse rates (a traditional damaging wind parameter) gener- ally did not discriminate between damaging and nondamaging wind convective environments. Other pa- rameters, such as convective available potential …

Trend Identification In Twentieth-Century U.S. Snowfall: The Challenges, Kenneth E. Kunkel, Michael A. Palecki, Kenneth G. Hubbard, David A. Robinson, Kelly T. Redmond, David R. Easterling

School of Natural Resources: Faculty Publications

There is an increasing interest in examining long-term trends in measures of snow climatology. An examination of the U.S. daily snowfall records for 1900–2004 revealed numerous apparent inconsistencies. For example, long-term snowfall trends among neighboring lake-effect stations differ greatly from insignificant to +100% century -1.

Internal inconsistencies in the snow records, such as a lack of upward trends in maximum seasonal snow depth at stations with large upward trends in snowfall, point to inhomogeneities. Nationwide, the frequency of daily observations with a 10:1 snowfall-to-liquid-equivalent ratio declined from 30% in the 1930s to a current value of around 10%, a change …

A Hybrid, Markov Chain-Based Model For Daily Streamflow Generation At Multiple Catchment Sites, Jozsef Szilagyi, Gabor Balint, Andras Csik

School of Natural Resources: Faculty Publications

No abstract provided.

Assessing Stream-Aquifer Interactions Through Inverse Modeling Of Flow Routing, Jozsef Szilagyi, Marc B. Parlange, Gabor Balint

School of Natural Resources: Faculty Publications

No abstract provided.

Discussion Of "Estimation Of The Water Balance Using Observed Soil Water In The Nebraska Sandhills" By V. Sridhar And K.G. Hubbard, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

Simulation Of The Superimposition Of Floods In The Upper Tisza Region, In "Transboundary Floods: Reducing Risks Through Flood Management", Jozsef Szilagyi, Gabor Balint, Andras Csik, Balazs Gauzer, Margit Horoszne Gulyas

School of Natural Resources: Faculty Publications

No abstract provided.

Ownership Structure, Corporate Governance And Top Management Fraud In Listed Companies: An Empirical Analysis Based On Chinese Cases, H. Zhou, J. Li, T. Liu

School of Natural Resources: Faculty Publications

No abstract provided.

Comment On "Using Numerical Modelling To Evaluate The Capillary Fringe Groundwater Ridging Hypothesis Of Streamflow Generation" By H. L. Cloke, M. G. Anderson, J. J. Mcdonnell, And J. P. Renaud, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

Methodology And Results Of Calculating Central California Surface Temperature Trends: Evidence Of Human-Induced Climate Change?, John R. Christy, William B. Norris, Kelly Redmond, Kevin P. Gallo

School of Natural Resources: Faculty Publications

A procedure is described to construct time series of regional surface temperatures and is then applied to interior central California stations to test the hypothesis that century-scale trend differences between irrigated and non-irrigated regions may be identified. The procedure requires documentation of every point in time at which a discontinuity in a station record may have occurred through (a) the examination of metadata forms (e.g., station moves) and (b) simple statistical tests. From this “homogeneous segments” of temperature records for each station are defined. Biases are determined for each segment relative to all others through a method employing mathematical graph …

Prevalence And Serovars Of Salmonella In The Feces Of Free-Ranging White-Tailed Deer (Odocoileus Virginianus) In Nebraska, David G. Renter, David P. Gnad, Jan M. Sargeant, Scott E. Hygnstrom

School of Natural Resources: Faculty Publications

To determine the prevalence and serovars of Salmonella in free-ranging deer, we cultured feces from white-tailed deer (Odocoileus virginianus) harvested by hunters during a regular firearm season in southeastern Nebraska (USA). We recovered Salmonella from 5 (1%; 95% confidence interval: 0.37– 2.20%) of 500 samples and identified four different Salmonella enterica serovars [Litchfield (1), Dessau (1), Infantis (2), and Enteritidis (1)]. Although the prevalence of Salmonella in free-ranging deer appears to be low, the serovars recovered are known to be pathogenic to humans and animals.

Absorption Properties Of Dissolved And Particulate Matter In Turbid Productive Inland Lakes, Giorgio Dall'olmo, Anatoly A. Gitelson

School of Natural Resources: Faculty Publications

The objective of this study is to extend the knowledge on the absorption properties of turbid productive lakes by describing the spectral characteristics of a_CDOM, a_nap and a_φ spectra measured in an agriculturally dominated region of North America (Nebraska, USA).

Three-Band Model For Noninvasive Estimation Of Chlorophyll Carotenoids And Anthocyanin Contents In Higher Plant Leaves, Anatoly A. Gitelson, Galina P. Keydan, Mark N. Merzlyak

School of Natural Resources: Faculty Publications

Leaf pigment content and composition provide important information about plant physiological status. Reflectance measurements offer a rapid, nondestructive technique to estimate pigment content. This paper describes a recently developed three-band conceptual model capable of remotely estimating total of chlorophylls, carotenoids and anthocyanins contents in leaves from many tree and crop species. We tuned the spectral regions used in the model in accord with pigment of interest and the optical characteristics of the leaves studied, and showed that the developed technique allowed accurate estimation of total chlorophylls, carotenoids and anthocyanins, explaining more than 91%, 70% and 93% of pigment variation, respectively. …

Ecophysiology Of Two Native Invasive Woody Species And Two Dominant Warm-Season Grasses In The Semiarid Grasslands Of The Nebraska Sandhills, Kathleen D. Eggemeyer, Tala Awada, David A. Wedin, F. Edwin Harvey, Xinhua Zhou

School of Natural Resources: Faculty Publications

Populations of Pinus ponderosa and Juniperus virginiana are expanding into semiarid Sandhills grasslands in Nebraska. To evaluate the physiological basis of their success, we measured the seasonal course of leaf gas exchange, plant water status, and carbon isotope discrimination in these two native trees and two native C₄ grasses (Schizachyrium scoparium and Panicum virgatum). Compared to the trees, grasses had higher net photosynthetic rates (A_net) and water use efficiency (WUE) and more negative predawn and midday water potentials (Ψ) in June and July. While leaf Ψ and rates of leaf gas exchange declined for all …

Relationship Between Gross Primary Production And Chlorophyll Content In Crops: Implications For The Synoptic Monitoring Of Vegetation Productivity, Anatoly A. Gitelson, Andrés Viña, Shashi Verma, Donald C. Rundquist, Timothy J. Arkebauer, Galina P. Keydan, Bryan Leavitt, Veronica Ciganda, George G. Burba, Andrew E. Suyker

School of Natural Resources: Faculty Publications

Accurate estimation of spatially distributed CO2 fluxes is of great importance for regional and global studies of carbon balance. We applied a recently developed technique for remote estimation of crop chlorophyll content to assess gross primary production (GPP). The technique is based on reflectance in two spectral channels: the near-infrared and either the green or the red-edge. We have found that in irrigated and rainfed crops (maize and soybean), midday GPP is closely related to total crop chlorophyll content. The technique provided accurate estimations of midday GPP in both crops under rainfed and irrigated conditions with root mean square error …

Call-By-Name Calculus Of Records And Its Basic Properties, Elena Machkasova, Emily Christiansen

Faculty Working Papers

No abstract provided.

Sabbatical Leave Proposal And Report, Ken Urban

Sabbaticals

I plan to use my sabbatical time creating live websites/ databases/ web services for not-for-profit businesses. I plan to create them using the rich variety of different tools I have been teaching. I think it is important that I not only build these sites, but also interact with groups who will be using the sites while building them.

I plan to write a time-based contract with the entities for whom I will consultant pro bono for. Of the many benefits, this will ensure an end for the work, to prevent this from interfering with my future work at Parkland. This …

Structure And Bonding Of Au5m (M=Na, Mg, Al, Si, P, And S) Clusters, Chiranjib Majumder, Anil K. Kandalam, Puru Jena

Physics Publications

The atomic and electronic structure of Au5M (M=Na, Mg, Al, Si, P, S, and Au) clusters have been investigated using generalized gradient approximation to the density functional theory. Depending on the nature of interaction with different impurity elements a structural transition from planar to nonplanar configuration has been observed in Au5M. With the exception of S, impurities with p electrons (Al, Si, P) yield nonplanar geometries of Au5M clusters, while those with selectrons (Na, Mg) yield planar geometries. The properties of Au5Scluster are anomalous: The cluster not only has a planar geometry, but also is chemically most stable with the …

Effect Of Ti And Metal Vacancies On The Electronic Structure, Stability, And Dehydrogenation Of Na3alh6: Supercell Band-Structure Formalism And Gradient-Corrected Density-Functional Theory, S. Li, Puru Jena

Physics Publications

Electronic and structural properties of sodium-aluminum hexahydride (Na3AlH6) formed during the decomposition reaction of sodium alanate (NaAlH4) and the effects of Ti catalyst are studied using supercell approach and density-functional theory. The preferred site of Ti has been determined by substituting it at both the Na and Al sites and comparing the respective formation energies. The least unfavorable site for Ti is found to be the Al site. To examine the role of Ti substitution on the desorption of hydrogen, the energy cost to remove a H atom from the vicinity of Ti was calculated and compared with that from …

Effect Of Au Coating On The Magnetic And Structural Properties Of Fe Nanoclusters For Use In Biomedical Applications: A Density-Functional Theory Study, Q. Sun, A. K. Kandalam, Q. Wang, Puru Jena, Y. Kawazoe, M. Marquez

Physics Publications

In this paper, we report the first systematic theoretical study of gold-coated iron nanoclusters, aiming at understanding the magnetic properties of this core-shell structure used in biomedical applications. The calculations based on density-functional theory focus on the effect of gold coating on the magnetic and structural properties of iron clusters of various sizes, and the reaction of the bare and coated iron clusters with oxygen. Our results show that the magnetic moment of iron nanocore with gold coating is still significantly higher than that in bulk Fe; the coupling between Fe atoms remained ferromagnetic and is insensitive to the thickness …

Structure And Stability Of Co-N(Pyridine)(M)(-) Clusters: Absence Of Metal Inserted Structures, B. Douglas Edmonds, A. K. Kandalam, S. N. Khanna, X. Li, A. Grubisic, I. Khanna, K. H. Bowen

Physics Publications

A synergistic approach combining the experimental photoelectron spectroscopy and theoretical electronic structure studies is used to probe the geometrical structure and the spin magnetic moment of Con(pyridine)−m clusters. It is predicted that the ground state of Co(pyridine)− is a structure where the Co atom is inserted in a CH bond. However, the insertion is marked by a barrier of 0.33eV that is not overcome under the existing experimental conditions resulting in the formation of a structure where Co occupies a site above the pyridine plane. For Co2(pyridine)−, a ground-state structure is predicted in which the Co2 diametric moiety is inserted …

Hydrogen Storage And The 18-Electron Rule, Boggavarapu Kiran, Anil K. Kandalam, Puru Jena

Physics Publications

We show that the 18-electron rule can be used to design new organometallic systems that can store hydrogen with large gravimetric density. In particular, Ti containing organic molecules such as C4H4, C5H5, and C8H8 can store up to 9wt% hydrogen, which meets the Department of Energy target for the year 2015. More importantly, hydrogen in these materials is stored in molecular form with an average binding energy of about 0.55eV∕H2 molecule, which is ideal for fast kinetics. Using molecular orbitals we have analyzed the maximum number of H2 molecules that can be adsorbed as well as the nature of their …

Gold As Hydrogen: Structural And Electronic Properties And Chemical Bonding In Si3au3+/0/- And Comparisons To Si3h3+/0/-, Boggavarapu Kiran, Xi Li, Hua-Jin Zhai, Lai-Sheng Wang

Physics Publications

A single Au atom has been shown to behave like H in its bonding to Si in several mono- and disilicon gold clusters. In the current work, we investigate the Au∕H analogy in trisilicon gold clusters, Si3Au+∕0∕−3. Photoelectron spectroscopy and density functional calculations are combined to examine the geometric and electronic structure of Si3Au−3. We find that there are three isomers competing for the ground state of Si3Au−3 as is the case for Si3H−3. Extensive structural searches show that the potential energy surfaces of the trisilicon gold clusters (Si3Au−3, Si3Au3, and Si3Au+3) are similar to those of the corresponding silicon …