Physical Sciences and Mathematics Commons^™

Foreword Of Kentucky Alfalfa And Stored Forages Conference [2017], S. Ray Smith, Krista Lea

Kentucky Alfalfa and Stored Forage Conference

This is the front matter of the proceedings.

Mass-Analyzed Threshold Ionization Spectroscopy Of Lanthanum-Hydrocarbon Radicals Formed By C—H Bond Activation Of Propene, Sudesh Kumari, Wenjin Cao, Dilrukshi C. Hewage, Ruchira Silva, Dong-Sheng Yang

Chemistry Faculty Publications

La(C₃H₄) and La(C₃H₆) are observed from the reaction of laser-vaporized La atoms with propene by photoionization time-of-flight mass spectrometry and characterized by mass-analyzed threshold ionization spectroscopy. Two isomers of La(C₃H₄) are identified as methyl-lanthanacyclopropene [La(CHCCH₃)] (C_s) and lanthanacyclobutene [La(CHCHCH₂)] (C₁); La(C₃H₆) is determined to be H—La(η³-allyl) (C_s), a C—H bond inserted species. All three metal-hydrocarbon radicals prefer a doublet ground state with a La 6s-based electron configuration. Ionization of the neutral doublet …

Laser Shock Wave Assisted Patterning On Niti Shape Memory Alloy Surfaces, Dovletgeldi Seyitliyev, Peizhen Li, Khomidkhodza Kholikov, Byron Grant, Haluk E. Karaca, Ali O. Er

Mechanical Engineering Faculty Publications

An advanced direct imprinting method with low cost, quick, and less environmental impact to create thermally controllable surface pattern using the laser pulses is reported. Patterned micro indents were generated on Ni₅₀Ti₅₀ shape memory alloys (SMA) using an Nd:YAG laser operating at 1064 nm combined with suitable transparent overlay, a sacrificial layer of graphite, and copper grid. Laser pulses at different energy densities which generates pressure pulses up to 10 GPa on the surface was focused through the confinement medium, ablating the copper grid to create plasma and transferring the grid pattern onto the NiTi surface. Scanning …

Recoverable Stress Induced Two-Way Shape Memory Effect On Niti Surface Using Laser-Produced Shock Wave, Dovletgeldi Seyitliyev, Peizhen Li, Khomidkhodza Kholikov, Byron Grant, Zachary Thomas, Orhan Alal, Haluk E. Karaca, Ali O. Er

Mechanical Engineering Faculty Publications

The surfaces of Ni50Ti50 shape memory alloys (SMAs) were patterned by laser scribing. This method is more simplistic and efficient than traditional indentation techniques, and has also shown to be an effective method in patterning these materials. Different laser energy densities ranging from 5 mJ/pulse to 56 mJ/pulse were used to observe recovery on SMA surface. The temperature dependent heat profiles of the NiTi surfaces after laser scribing at 56 mJ/pulse show the partially-recovered indents, which indicate a "shape memory effect (SME)" Experimental data is in good agreement with theoretical simulation of laser induced shock wave propagation inside NiTi SMAs. …

Single Molecule-Level Study Of Donor-Acceptor Interactions And Nanoscale Environment In Blends, Nicole Quist, Rebecca Grollman, Jeremy Rath, Alex Robertson, Michael Haley, John E. Anthony, Oksana Ostroverkhova

Chemistry Faculty Publications

Organic semiconductors have attracted considerable attention due to their applications in low-cost (opto)electronic devices. The most successful organic materials for applications that rely on charge carrier generation, such as solar cells, utilize blends of several types of molecules. In blends, the local environment strongly influences exciton and charge carrier dynamics. However, relationship between nanoscale features and photophysics is difficult to establish due to the lack of necessary spatial resolution. We use functionalized fluorinated pentacene (Pn) molecule as single molecule probes of intermolecular interactions and of the nanoscale environment in blends containing donor and acceptor molecules. Single Pn donor (D) molecules …

Q-Stirling Identities Revisited, Yue Cai, Richard Ehrenborg, Margaret Readdy

Mathematics Faculty Publications

We give combinatorial proofs of q-Stirling identities using restricted growth words. This includes a poset theoretic proof of Carlitz's identity, a new proof of the q-Frobenius identity of Garsia and Remmel and of Ehrenborg's Hankel q-Stirling determinantal identity. We also develop a two parameter generalization to unify identities of Mercier and include a symmetric function version.

Particle Physics Model For The 17 Mev Anomaly In Beryllium Nuclear Decays, Jonathan L. Feng, Bartosz Fornal, Iftah Galon, Susan Gardner, Jordan Smolinsky, Tim M. P. Tait, Philip Tanedo

Physics and Astronomy Faculty Publications

The 6.8σ anomaly in excited ⁸Be nuclear decays via internal pair creation is fit well by a new particle interpretation. In a previous analysis, we showed that a 17 MeV protophobic gauge boson provides a particle physics explanation of the anomaly consistent with all existing constraints. Here we begin with a review of the physics of internal pair creation in ⁸Be decays and the characteristics of the observed anomaly. To develop its particle interpretation, we provide an effective operator analysis for excited ⁸Be decays to particles with a variety of spins and parities and show that …

Nitrate Radicals And Biogenic Volatile Organic Compounds: Oxidation, Mechanisms And Organic Aerosol, Nga Lee Ng, Steven S. Brown, Alexander T. Archibald, Elliot Atlas, Ronald C. Cohen, John N. Crowley, Douglas A. Day, Neil M. Donahue, Juliane L. Fry, Hendrik Fuchs, Robert J. Griffin, Marcelo I. Guzman, Hartmut Hermann, Alma Hodzic, Yoshiteru Iinuma, José L. Jimenez, Astrid Kiendler-Scharr, Ben H. Lee, Deborah J. Luecken, Jingqiu Mao, Robert Mclaren, Anke Mutzel, Hans D. Osthoff, Bin Ouyang, Benedicte Picquet-Varrault, Ulrich Platt, Havala O. T. Pye, Yinon Rudich, Rebecca H. Schwantes, Manabu Shiraiwa, Jochen Stutz, Joel A. Thornton, Andreas Tilgner, Brent J. Williams, Rahul A. Zaveri

Chemistry Faculty Publications

Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO₃) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO₃-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number …

Dual-Functional-Tag-Facilitated Protein Labeling And Immobilization, Xinyi Zhang, Wei Lu, Kevin Kwan, Dibakar Bhattacharyya, Yinan Wei

Chemistry Faculty Publications

An important strategy in the construction of biomimetic membranes and devices is to use natural proteins as the functional components for incorporation in a polymeric or nanocomposite matrix. Toward this goal, an important step is to immobilize proteins with high efficiency and precision without disrupting the protein function. Here, we developed a dual-functional tag containing histidine and the non-natural amino acid azidohomoalanine (AHA). AHA is metabolically incorporated into the protein, taking advantage of the Met-tRNA and Met-tRNA synthetase. Histidine in the tag can facilitate metal-affinity purification, whereas AHA can react with an alkyne-functionalized probe or surface via well-established click chemistry. …

Contemporary And Future Characteristics Of Precipitation Indices In The Kentucky River Basin, Somsubhra Chattopadhyay, Dwayne R. Edwards, Yao Yu

Biosystems and Agricultural Engineering Faculty Publications

Climatic variability can lead to large-scale alterations in the hydrologic cycle, some of which can be characterized in terms of indices involving precipitation depth, duration and frequency. This study evaluated the spatiotemporal behavior of precipitation indices over the Kentucky River watershed for both the baseline period of 1986–2015 and late-century time frame of 2070–2099. Historical precipitation data were collected from 16 weather stations in the watershed, while future rainfall time-series were obtained from an ensemble of 10 Coupled Model Intercomparison Project Phase 5 (CMIP5) global circulation models under two future emission pathways: Representative Concentration Pathways (RCP) 4.5 and 8.5. Annual …

Effect Of Seed Position On Parental Plant On Proportion Of Seeds Produced With Nondeep And Intermediate Physiological Dormancy, Juan J. Lu, Dun Y. Tan, Carol C. Baskin, Jerry M. Baskin

Biology Faculty Publications

The position in which seeds develop on the parental plant can have an effect on dormancy-break and germination. We tested the hypothesis that the proportion of seeds with intermediate physiological dormancy (PD) produced in the proximal position on a raceme of Isatis violascens plants is higher than that produced in the distal position, and further that this difference is related to temperature during seed development. Plants were watered at 3-day intervals, and silicles and seeds from the proximal (early) and distal (late) positions of racemes on the same plants were collected separately and tested for germination. After 0 and 6 …

Predicted Electronic Markers For Polytypes Of Laobis2 Examined Via Angle-Resolved Photoemission Spectroscopy, Xiaoqing Zhou, Qihang Liu, J. A. Waugh, T. Nummy, Xiuwen Zhang, Xiangde Zhu, Gang Cao, Alex Zunger, D. S. Dessau

Physics and Astronomy Faculty Publications

The natural periodic stacking of symmetry-inequivalent planes in layered compounds can lead to the formation of natural superlattices; albeit close in total energy, (thus in their thermodynamic stability), such polytype superlattices can exhibit different structural symmetries, thus have markedly different electronic properties which can in turn be used as “structural markers”. We illustrate this general principle on the layered LaOBiS₂ compound where density-functional theory (DFT) calculations on the (BiS₂)/(LaO)/(BiS₂) polytype superlattices reveal both qualitatively and quantitatively distinct electronic structure markers associated with the Rashba physics, yet the total energies are only ∼ 0.1 meV apart. …

The Jcmt Nearby Galaxies Legacy Survey – Xi. Environmental Variations In The Atomic And Molecular Gas Radial Profiles Of Nearby Galaxies, Angus Mok, C. D. Wilson, J. H. Knapen, José R. Sánchez-Gallego, E. Brinks, E. Rosolowsky

Physics and Astronomy Faculty Publications

We present an analysis of the radial profiles of a sample of 43 H I-flux selected spiral galaxies from the Nearby Galaxies Legacy Survey (NGLS) with resolved James Clerk Maxwell Telescope (JCMT) CO J = 3 − 2 and/or Very Large Array (VLA) H I maps. Comparing the Virgo and non-Virgo populations, we confirm that the H i discs are truncated in the Virgo sample, even for these relatively H i-rich galaxies. On the other hand, the H₂ distribution is enhanced for the Virgo galaxies near their centres, resulting in higher H₂ to H I ratios and steeper …

The Dusty Tori Of Nearby Qsos As Constrained By High-Resolution Mid-Ir Observations, M. Martínez-Paredes, I. Aretxaga, A. Alonso-Herrero, O. González-Martín, E. Lopéz-Rodríguez, C. Ramos Almeida, A. Asensio Ramos, T. Diaz Santos, Moshe Elitzur, P. Esquej, A. Hernán-Caballero, K. Ichikawa, R. Nikutta, C. Packham, M. Pereira-Santaella, C. Telesco

Physics and Astronomy Faculty Publications

We present mid-infrared (MIR; 7.5–13.5 μm) imaging and spectroscopy observations obtained with the CanariCam (CC) instrument on the 10.4-m Gran Telescopio CANARIAS for a sample of 20 nearby, MIR bright and X-ray luminous quasi-stellar objects (QSOs). We find that for the majority of QSOs the MIR emission is unresolved at angular scales ∼0.3 arcsec, corresponding to physical scales ≲ 600 pc. We find that the higher-spatial resolution CC spectra have similar shapes to those obtained with Spitzer/IRS, and hence we can assume that the spectra are not heavily contaminated by extended emission in the host galaxy. We thus take …

Us Residential Building Air Exchange Rates: New Perspectives To Improve Decision Making At Vapor Intrusion Sites, Rivka Reichman, Elham Shirazi, Donald G. Colliver, Kelly G. Pennell

Civil Engineering Faculty Publications

Vapor intrusion (VI) is well-known to be difficult to characterize because indoor air (IA) concentrations exhibit considerable temporal and spatial variability in homes throughout impacted communities. To overcome this and other limitations, most VI science has focused on subsurface processes; however there is a need to understand the role of aboveground processes, especially building operation, in the context of VI exposure risks. This tutorial review focuses on building air exchange rates (AERs) and provides a review of literature related building AERs to inform decision making at VI sites. Commonly referenced AER values used by VI regulators and practitioners do not …

Testing Atomic Collision Theory With The Two-Photon Continuum Of Astrophysical Nebulae, Francisco Guzmán, N. R. Badnell, Marios Chatzikos, P. A. M. Van Hoof, R. J. R. Williams, Gary J. Ferland

Physics and Astronomy Faculty Publications

Accurate rates for energy-degenerate l-changing collisions are needed to determine cosmological abundances and recombination. There are now several competing theories for the treatment of this process, and it is not possible to test these experimentally. We show that the H i two-photon continuum produced by astrophysical nebulae is strongly affected by l-changing collisions. We perform an analysis of the different underlying atomic processes and simulate the recombination and two-photon spectrum of a nebula containing H and He. We provide an extended set of effective recombination coefficients and updated l-changing 2s − 2p transition rates using …

Ergot And Loline Alkaloid Concentrations In Endophyte-Infected Tall Fescue Tillers, Rebecca L. Mcculley

Forage Climate Change Experiment Research Data

Approximately 40 tall fescue tillers were randomly collected and frozen from each of the 20 treatment plots.

Tillers were cut at 7.6 cm above ground level and tested for the presence of the Epichloe endophyte using an enzyme-linked immunosorbent assay.

Tillers from each plot were sorted into 'infected' vs 'uninfected' groups, lyophilized, and ground through a 1mm screen using a Cyclotec 1093 mill.

Ground material from the endophyte infected tillers was analyzed for ergot and loline alkaloids in the lab of Lowell Bush at the University of Kentucky, Plant and Soil Sciences Dept.

For details on alkaloid analyses see: McCulley …

Effects Of Litter On Seedling Emergence And Seed Persistence Of Three Common Species On The Loess Plateau In Northwestern China, Rui Zhang, Xiaowen Hu, Jerry M. Baskin, Carol C. Baskin, Yanrong Wang

Biology Faculty Publications

Litter accumulation resulting from land use change (enclosure) is one of the key variables influencing seedling recruitment and consequently the regeneration of plant populations and seed persistence in the soil seed bank. A better understanding of the effects of litter on seed germination and seedling emergence is crucial for developing a new set of indicators for grassland ecosystem health and for grassland management policy. We investigated the effects of seed position in litter and amount of litter covering the seed on seedling emergence and seed persistence of three common species on the Loess Plateau in northwestern China. Seed position beneath …

Structure And Physical Properties Of Srniru5O11 Single Crystals: An R-Type Ferrite Based On Ordered Kagome Nets, L. Shlyk, Lance E. De Long, R. Niewa

Physics and Astronomy Faculty Publications

Single crystals of the R-type ferrite SrNiRu₅O₁₁ were grown from a chloride flux. The hexagonal crystal structure contains ruthenium located on distorted kagome nets. The low-temperature dc magnetic susceptibilities (χ_⊥ and χ_∥, perpendicular and parallel to the c axis, respectively) diverge as T^−0.3, and do not exhibit any indication of long-range magnetic order down to 4.5 K. The electrical resistivity varies as T^1.6 below 40 K, which is typical of non-Fermi liquids, and may originate from a competition between residual magnetic interactions among Ni²⁺ (S = 1) spins …

Locality And Efficient Evaluation Of Lattice Composite Fields: Overlap-Based Gauge Operators, Andrei Alexandru, Ivan Horváth

Physics and Astronomy Faculty Publications

We propose a novel general approach to locality of lattice composite fields, which in case of QCD involves locality in both quark and gauge degrees of freedom. The method is applied to gauge operators based on the overlap Dirac matrix elements, showing for the first time their local nature on realistic path-integral backgrounds. The framework entails a method for efficient evaluation of such nonultralocal operators, whose computational cost is volume independent at fixed accuracy, and only grows logarithmically as this accuracy approaches zero. This makes computation of useful operators, such as overlap-based topological density, practical. The key notion underlying these …

Strange Quark Magnetic Moment Of The Nucleon At The Physical Point, Raza Sabbir Sufian, Yi-Bo Yang, Andrei Alexandru, Terrence Draper, Jian Liang, Keh-Fei Liu

Physics and Astronomy Faculty Publications

We report a lattice QCD calculation of the strange quark contribution to the nucleon’s magnetic moment and charge radius. This analysis presents the first direct determination of strange electromagnetic form factors including at the physical pion mass. We perform a model-independent extraction of the strange magnetic moment and the strange charge radius from the electromagnetic form factors in the momentum transfer range of 0.051  GeV² ≲ Q² ≲ 1.31  GeV². The finite lattice spacing and finite volume corrections are included in a global fit with 24 valence quark masses on four lattices with different lattice spacings, …

Seed Dormancy-Breaking In A Cold Desert Shrub In Relation To Sand Temperature And Moisture, Huiliang Liu, Buhailiqiemu Abudureheman, Lingwei Zhang, Jerry M. Baskin, Carol C. Baskin, Daoyuan Zhang

Biology Faculty Publications

Seasonal periodicity of seed germination and its relationship to seasonal changes in temperature and soil moisture have been well studied in seeds of species with physiological dormancy. However, relatively little information is available on the role of these environmental factors in controlling germination of seeds with physical dormancy (PY). Our primary aim was to determine if seeds of the cold desert sand dune semi-shrub Eremosparton songoricum exhibits seasonal periodicity of seed germination and the relationship between seed dormancy break and soil temperature and moisture. In the laboratory, seeds incubated on dry, wet, wet-dry and dry-wet sand were exposed to a …

Nuclear Structure Of 76Ge From Inelastic Neutron Scattering Measurements And Shell Model Calculations, Sharmistha Mukhopadhyay, Benjamin P. Crider, B. A. Brown, S. F. Ashley, Anagha Chakraborty, A. Kumar, Marcus T. Mcellistrem, Erin E. Peters, Francisco M. Prados-Estévez, Steven W. Yates

Physics and Astronomy Faculty Publications

The low-lying, low-spin levels of ⁷⁶Ge were studied with the (n,n′γ) reaction. Gamma-ray excitation function measurements were performed at incident neutron energies from 1.6 to 3.7 MeV, and γ-ray angular distributions were measured at neutron energies of 3.0 and 3.5 MeV. From these measurements, level spins, level lifetimes, γ-ray intensities, and multipole mixing ratios were determined. No evidence for a number of previously placed levels was found. Below 3.3 MeV, many new levels were identified, and the level scheme was re-evaluated. The B(E2) values support low-lying band structure. The 2 …

Fischer–Tropsch Synthesis: Effect Of Ammonia On Product Selectivities For A Pt Promoted Co/Alumina Catalyst, Venkat Ramana Rao Pendyala, Wilson D. Shafer, Gary Jacobs, Michela Martinelli, Dennis E. Sparks, Burtron H. Davis

Center for Applied Energy Research Faculty and Staff Publications

The effects of co-fed ammonia in synthesis gas on the activity and product selectivities of a typical cobalt catalyst (0.5% Pt–25% Co/Al₂O₃) were investigated during the Fischer–Tropsch synthesis using a continuously stirred tank reactor (CSTR). The product selectivities were compared at a similar CO conversion level for various concentrations (10–1000 ppmv) of ammonia, as well as clean (un-poisoned) conditions. The addition of 10–1000 ppmv ammonia (concentration of ammonia with respect to the syngas feed) significantly decreased activity; the percentage of deactivation was similar (∼40%) for the various concentrations of ammonia used. At similar CO conversions, the …

Inelastic Neutron Scattering Cross Section Measurements For 134,136Xe Of Relevance To Neutrinoless Double-Β Decay Searches, Erin E. Peters, T. J. Ross, S. H. Liu, Marcus T. Mcellistrem, Steven W. Yates

Chemistry Faculty Publications

Neutrinoless double-β decay (0νββ) searches typically involve large-scale experiments for which backgrounds can be complex. One possible source of background near the 0νββ signature in the observed spectra is γ rays arising from inelastic neutron scattering from the materials composing or surrounding the detector. In relation to searches for the 0νββ of ¹³⁶Xe to ¹³⁶Ba, such as the EXO-200 and KamLAND-Zen projects, inelastic neutron scattering γ-ray production cross sections for ¹³⁶Xe and ¹³⁴Xe are of importance for characterizing such γ rays that may inhibit the unambiguous identification of this yet-to-be-observed …

Signed Lozenge Tilings, D. Cook Ii, Uwe Nagel

Mathematics Faculty Publications

It is well-known that plane partitions, lozenge tilings of a hexagon, perfect matchings on a honeycomb graph, and families of non-intersecting lattice paths in a hexagon are all in bijection. In this work we consider regions that are more general than hexagons. They are obtained by further removing upward-pointing triangles. We call the resulting shapes triangular regions. We establish signed versions of the latter three bijections for triangular regions. We first investigate the tileability of triangular regions by lozenges. Then we use perfect matchings and families of non-intersecting lattice paths to define two signs of a lozenge tiling. Using a …

Microbial Interactions In The Phyllosphere Increase Plant Performance Under Herbivore Biotic Stress, Muhammad Saleem, Nicole Meckes, Zahida H. Pervaiz, Milton B. Traw

Plant and Soil Sciences Faculty Publications

The phyllosphere supports a tremendous diversity of microbes and other organisms. However, little is known about the colonization and survival of pathogenic and beneficial bacteria alone or together in the phyllosphere across the whole plant life-cycle under herbivory, which hinders our ability to understand the role of phyllosphere bacteria on plant performance. We addressed these questions in experiments using four genetically and biogeographically diverse accessions of Arabidopsis thaliana, three ecologically important bacterial strains (Pseudomonas syringae DC3000, Xanthomonas campestris, both pathogens, and Bacillus cereus, plant beneficial) under common garden conditions that included fungus gnats (Bradysia spp.). …

Moderator Biographies, Heart Of America Grazing Conference

Kentucky Grazing Conference

No abstract provided.

Grazing Panel, Jeff Beasley, Trevor Toland, Ted Krauskopf

Kentucky Grazing Conference

No abstract provided.

Cover Crops/Annuals And Grazing, Roger Staff

Kentucky Grazing Conference

The use of annual forages (cover crops), both summer and winter, have been utilized for several years. When cover crops first were used to extend the grazing season, it began with one to three species in a mixture. That was before the soil health benefits were being observed and discussed as they are now. There have been a wide variety of planting methods used: airplanes, helicopters, conventional and No-till drills. Some seeding methods is simply broadcast on the soils surface and lightly tilled in or just rained in depending upon the weather. Then we discovered the herbicides and amounts used …