cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Experimental observation of a chaos-to-chaos transition in laser droplet generation
Creators: name: Krese, Blaz
name: Perc, Matjaz
name: Govekar, Edvard
Publisher: name: arXiv
Year: 2010
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Dynamical Systems (math.DS)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We examine the dynamics of laser droplet generation in dependence on the detachment pulse power. In the absence of the detachment pulse, undulating pendant droplets are formed at the end of a properly fed metal wire due to the impact of the primary laser pulse that induces melting. Eventually, these droplets detach, i.e. overcome the surface tension, because of their increasing mass. We show that this spontaneous dripping is deterministically chaotic by means of a positive largest Lyapunov exponent and a negative divergence. In the presence of the detachment pulse, however, the generation of droplets is fastened depending on the pulse power. At high powers, the spontaneity of dripping is completely overshadowed by the impact of the detachment pulse. Still, amplitude chaos can be detected, which similarly as the spontaneous dripping, is characterized by a positive largest Lyapunov exponent and a negative divergence, thus indicating that the observed dynamics is deterministically chaotic with an attractor as solution in the phase space. In the intermediate regime, i.e. for low and medium detachment pulse powers, the two chaotic states compete for supremacy, yielding an intermittent period-doubling to amplitude chaos transition, which we characterize by means of recurrence plots and their properties. Altogether, the transition from spontaneous to triggered laser droplet generation is characterized by a chaos-to-chaos transition with an intermediate dynamically nonstationary phase in-between. Since metal droplets can be used in various industrial applications, we hope that the accurate determination of the dynamical properties underlying their formation will facilitate their use and guide future attempts at mathematical modeling.
description: 13 pages, 8 figures; accepted for publication in International Journal of Bifurcation and Chaos [related work available at http://arxiv.org/abs/1003.0473 and http://www.matjazperc.com/chaos/laser.html]
Frequency- and time-domain investigation of the dynamic properties of interlayer-exchange-coupled Ni81Fe19/Ru/Ni81Fe19 thin films
Creators: name: Belmeguenai, M.
name: Martin, T.
name: Woltersdorf, Georg
name: Maier, M.
name: Bayreuther, Günther
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik
subject: 75.40.Gb, 76.50.+g
subject: 75.70.−i
subject: 75.30.Et

description: Pulsed inductive microwave magnetometer (PIMM), conventional ferromagnetic resonance (FMR), and vector network analyzer FMR (VNA-FMR) have been used for complementary studies of the various excited modes in exchange-coupled NiFe(30 nm)/Ru(d(Ru))/NiFe(30 nm) films with variable Ru thicknesses d(Ru). For antiferromagnetically coupled layers, two modes, which vary in their relative intensity as a function of the bias field, are detected. These two modes, which are observable simultaneously over a limited range of the bias field with PIMM, are identified as optic and acoustic modes. The mode frequencies and the interlayer exchange coupling are found to oscillate as a function of the Ru layer thickness with a period of 8.5 A. The frequency oscillations of the optic mode are coupling dependent, while those of the acoustic mode are indirectly related to coupling via the canting angle of the layer magnetizations below the saturation. Comparison between PIMM and VNA-FMR in terms of frequency of modes shows good agreement, but the optic mode is observed over a wider field range with VNA-FMR. Furthermore, we clearly observed different behaviors of the FMR linewidths as a function of the spacer thickness for the optic and acoustic modes. In addition, perpendicular standing spin waves have been studied as a function of coupling. The FMR linewidth of the different modes increases with the microwave frequency and typical damping constants of alpha=0.0073 have been measured. The effect of the pulse field amplitudes on the properties of the various excited modes has been simulated and studied experimentally.
What's the point of documentation?
Creators: name: Pryor, Louise
Publisher: name: arXiv
Year: 2010
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: We give a brief characterisation of the purposes and forms of documentation in and of spreadsheets.
description: 4 Pages, 1 Colour Figure. Referenced by GJC in Nov 2010; ISBN:1-905617-08-9
Rural Young Adults' PerceptTioITnLsEof Cannabis: A Survey Study
Creators: name: Chen, Li
name: Xie, Ming
Publisher: name: Maryland Shared Open Access Repository
Year: 2024

description: This project examines rural young adults’ perceptions of cannabis (marijuana). The results of a paper-and-pencil and an online survey yielded four major findings. The research findings show the associations between exposure to social media messages about cannabis, moral foundations, perceived risks of cannabis, attitudes toward cannabis legalization, and word of mouth intentions to talk about cannabis in person and online. Data analysis suggests that young adults’ attitudes toward recreational cannabis and cannabis legalization are not predicted by time spent on social media, but are associated with specific moral foundations. The research findings show that health educators may consider embedding latent moral values in their drug-prevention campaigns that target rural young adults.
On neutrino-atom scattering in searches for neutrino magnetic moments
Creators: name: Kouzakov, Konstantin A.
name: Studenikin, Alexander I.
name: Voloshin, Mikhail B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: In the experimental searches for neutrino magnetic moments using germanium detectors one studies the ionization channel in the neutrino-atom scattering. We find that the so-called stepping approximation to the neutrino-impact ionization is exact in the semiclassical limit, and that the deviations from this approximation are very small.
description: 1 page, to appear in Nuclear Physics B Proceedings Supplement 2011 (Proceedings of the XXIV International Conference on Neutrino Physics and Astrophysics, Athens, June 14-19, 2010)
West Texas A&M University experts talk on preparation for emergency situations
Creators: name: Frazier, KyLeah
name: Xie, Ming
Publisher: name: Maryland Shared Open Access Repository
Year: 2023
Subjects: UMBC Emergency and Distaster Health Systems
Ming Xie

description: The recent disaster in Maui coupled with an approaching dry winter season here in the Panhandle highlights the dangers of wildfires and how being prepared makes a big difference.
Acoustic, thermal and flow processes in a water filled nanoporous glasses by time-resolved optical spectroscopy
Creators: name: Cucini, R.
name: Taschin, A.
name: Bartolini, P.
name: Torre, R.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We present heterodyne detected transient grating measurements on water filled Vycor 7930 in the range of temperature 20 - 90 degrees C. This experimental investigation enables to measure the acoustic propagation, the average density variation due the liquid flow and the thermal diffusion in this water filled nano-porous material. The data have been analyzed with the model of Pecker and Deresiewicz which is an extension of Biot model to account for the thermal effects. In the whole temperature range the data are qualitatively described by this hydrodynamic model that enables a meaningful insight of the different dynamic phenomena. The data analysis proves that the signal in the intermediate and long time-scale can be mainly addressed to the water dynamics inside the pores. We proved the existence of a peculiar interplay between the mass and the heat transport that produces a flow and back-flow process inside the nano-pores. During this process the solid and liquid dynamics have opposite phase as predicted by the Biot theory for the slow diffusive wave. Nevertheless, our experimental results confirm that transport of elastic energy (i.e. acoustic propagation), heat (i.e. thermal diffusion) and mass (i.e. liquid flow) in a liquid filled porous glass can be described according to hydrodynamic laws in spite of nanometric dimension of the pores. The data fitting, based on the hydrodynamic model, enables the extraction of several parameters of the water-Vycor system, even if some discrepancies appear when they are compared with values reported in the literature.
description: 32 pages, 11 figures
Spin dynamics in ultrathin film structures with a network of misfit dislocations
Creators: name: Woltersdorf, Georg
name: Heinrich, B.
name: Woltersdorf, J.
name: Scholz, R.
Publisher: name: Universität Regensburg
Year: 2004
Subjects: subject: gold, iron, palladium, magnetic multilayers, ferromagnetic materials, spin dynamics, magnons, ferromagnetic resonance, transmission electron microscopy, dislocations
subject: 530 Physik
subject: 75.70.Cn
subject: 75.50.Bb
subject: 76.50.+g
subject: 68.37.Lp
subject: 61.72.Ff

description: Using ferromagnetic resonance (FMR) and transmission electron microscopy we studied the structural and magnetic properties of lattice mismatched magnetic ultrathin multilayers of the system Au/Fe/Au/Pd/Fe(001) prepared on GaAs(001). We observed a correlation between the periodic lattice irregularities due to the misfit accommodation processes and the resulting magnetic properties of the multilayer system: In samples with a network of misfit dislocations the FMR measurements have shown that a significant part of the damping is extrinsic and caused by two magnon scattering. The angular dependence of the FMR linewidth reflects the in-plane symmetry of the dislocation arrangement. (C) 2004 American Institute of Physics.
title: Make Hay While the Sun Shines: How Community Organizations Help Refugees in Preparation for Disasters
title: Make Hay While the Sun Shines: How Community-Based Nonprofit Organizations Cultivate Refugees' Social Capital and Disaster Resilience
titleType: AlternativeTitle
Creators: name: Xie, Ming
name: Chen, Li
Publisher: name: Maryland Shared Open Access Repository
Year: 2023

description: This article examines community-based nonprofit organizations' (CBOs') perspectives and practices regarding cultivating refugees' disaster resilience. Adopting the theoretical framework of structural and cognitive social capital, we conducted in-depth interviews with leaders, staff members, and volunteers from refugee-serving organizations. The research findings offer new insights into how CBOs help refugees obtain multiple forms of social capital and develop disaster resilience through education and training, resource mobilization, planning, and coordination. The research findings also reveal the flow of social capital exchange during the disaster resilience cultivation process. Similar CBOs can rely on our research findings to develop evidence-based programs and interventions to help culturally and linguistically diverse groups gain social capital and improve disaster resilience.
Vortex Core Switching by Coherent Excitation with Single In-Plane Magnetic Field Pulses
Creators: name: Weigand, Markus
name: Van Waeyenberge, Bartel
name: Vansteenkiste, Arne
name: Curcic, Michael
name: Sackmann, Vitalij
name: Stoll, Hermann
name: Tyliszczak, Tolek
name: Kaznatcheev, Konstantine
name: Bertwistle, Drew
name: Woltersdorf, Georg
name: Back, Christian H.
name: Schuetz, Gisela
Publisher: name: Universität Regensburg
Year: 2009
Subjects: subject: 530 Physik
subject: 75.40.Gb
subject: 75.60.Jk
subject: 75.75.+a

description: The response of magnetic vortex cores to subnanosecond in-plane magnetic field pulses was studied by time-resolved x-ray microscopy. Vortex core reversal was observed and the switching events were located in space and time. This revealed a mechanism of coherent excitation by the leading and trailing edges of the pulse, lowering the field amplitude required for switching. The mechanism was confirmed by micromagnetic simulations and can be understood in terms of gyration around the vortex equilibrium positions, displaced by the applied field.
Microwave spectroscopy with vector network analyzer for interlayer exchange-coupled symmetrical and asymmetrical NiFe/Ru/NiFe
Creators: name: Belmeguenai, M.
name: Martin, T.
name: Woltersdorf, Georg
name: Bayreuther, Günther
name: Baltz, V.
name: Suszka, A. K.
name: Hickey, B. J.
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: 530 Physik

description: Vector network analyzer ferromagnetic resonance spectroscopy (VNA-FMR) is used here to study the different excited modes of sputtered asymmetrical NiFe(13.6 nm)/Ru(d(Ru))/NiFe(27.2 nm) exchange-coupled films with variable Ru thicknesses. The obtained results have been compared to those of the symmetrical NiFe( 30 nm)/Ru( dRu)/NiFe( 30 nm). In both cases, the measurements show the existence of an optic and an acoustic precessional mode. The optic mode was only observed over limited field ranges, especially in the symmetrical trilayers. To overcome such a limitation, we developed a new technique similar to the longitudinal FMR, where the bias and the rf field are parallel to each other and perpendicular to the pinning field. Interestingly, and in contrast to the symmetrical trilayers, we observed a mode anti-crossing in the dispersion relation of the asymmetrical layers that we attributed to the thickness difference between the two NiFe layers. Our experimental results on the effect of the biquadratic coupling on the mode frequency variations are in good agreement with the theory.
Time resolved magnetization dynamics of ultrathin Fe(001) films: Spin-pumping and two-magnon scattering
Creators: name: Woltersdorf, Georg
name: Buess, Matthias
name: Heinrich, B.
name: Back, Christian
Publisher: name: Universität Regensburg
Year: 2005
Subjects: subject: 530 Physik
subject: 78.20.Ls
subject: 75.30.−m

description: The time-resolved magnetic response of ultrathin epitaxial Fe(001) films grown on GaAs(001) and covered by Au, Pd, and Cr capping layers was investigated by time and spatially resolved Kerr effect measurements. The magnetization was excited by an in-plane magnetic field pulse using the transient internal field generated at a Schottky barrier while the wavelength of the excitation (resonant mode) was roughly 4 mu m. Each of the three cap layers affected the spin relaxation in a unique way. Au cap layers resulted in the bulk Gilbert damping of the Fe film. Pd cap layers caused an additional Gilbert damping due to spin-pump or spin-sink effects. Cr cap layers lead to a strong extrinsic damping which can be described by two-magnon scattering. In this case the strength of the extrinsic damping can be controlled by a field induced shift of the spin wave manifold with respect to the excited k vector.
Building the Fire Energetics and Emissions Research (FEER) Smoke Emissions Inventory Version 1.0
Creators: name: Ellison, Luke
name: Ichoku, Charles
name: Zhang, Feng
name: Wang, Jun
Publisher: name: Maryland Shared Open Access Repository
Year: 2014
Subjects: Environment Pollution
Computer Programming And Software

description: 2014 MODIS Science Team Meeting, Columbia, MD, United States, 29 April 2014 - 1 May 2014
description: The Fire Energetics and Emissions Research (FEER) group's new coefficient of emission global gridded product at 1x1 resolution that directly relates fire readiative energy (FRE) to smoke aerosol release, FEERv1.0 Ce, made its public debut in August 2013. Since then, steps have been taken to generate corresponding maps and totals of total particulate matter (PM) emissions using different sources of FRE, and subsequently to simulate the resulting PM₂.₅ in the WRF-Chem 3.5 model using emission rates from FEERv1.0 as well as other standard biomass burning emission inventories. An flowchart of the FEER algorithm to calculate Ce is outlined here along with a display of the resulting emissions of total PM globally and also regionally. The modeling results from the WRF-Chem3.5 simulations are also shown.
How 5G will impact on Vertical Industries Paper - 5G Network Slicing enabling Smart Energy-as-a-Service
Creators: name: Fiorentino, G.
name: A. Corsi
Publisher: name: Zenodo
Year: 2019
Subjects: 5G
SDN
NFV
VNF
Smart Grid
5G-PPP
eMBB
xMBB
mMTC

description: The 5G plays an enabler role by making some vertical industries smarter, faster and efficient harnessing Ultrahigh bandwidth, Ultra-low latency, and an Ultra large number of connections which will change the operating and working modes of core services in vertical industries. In this respect, the 5G is to able to guarantee optimal communications of the energy grid deploying, operating and managing existing and new 5G communications techniques and energy infrastructures (in the context of the Smart Energy-as-a-Service) easier, safer, more secure and resilient from an operational and financial point of view.
description: This work is part of the NRG-5 project which has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 762013.
Structural and magnetic properties of NiMnSb/InGaAs/InP(001)
Creators: name: Koveshnikov, A.
name: Woltersdorf, Georg
name: Liu, J. Q.
name: Kardasz, B.
name: Mosendz, O.
name: Heinrich, B.
name: Kavanagh, K. L.
name: Bach, P.
name: Bader, A. S.
name: Schumacher, C.
name: Ruster, C.
name: Gould, C.
name: Schmidt, G.
name: Molenkamp, L. W.
name: Kumpf, C.
Publisher: name: Universität Regensburg
Year: 2005
Subjects: subject: 530 Physik

description: The structural and magnetic properties of NiMnSb films, 5-120 nm thick, grown on InGaAs/InP(001) substrates by molecular-beam epitaxy, were studied by x-ray diffraction, transmission electron microscopy (TEM), and ferromagnetic resonance (FMR) techniques. X-ray diffraction and TEM studies show that the NiMnSb films had the expected half-Heusler structure, and films up to 120 nm were pseudomorphically strained at the interface, greater than the critical thickness for this system, about 70 nm (0.6% mismatch to InP). No interfacial misfit dislocations were detected up to 85 nm, however, relaxation in the surface regions of films thicker than 40 nm was evident in x-ray reciprocal space maps. TEM investigations show that bulk, planar defects are present beginning in the thinnest film (10 nm). Their density remains constant but they gradually increase in size with increasing film thickness. By 40 nm these defects have overlapped to form a quasicontinuous network aligned closely with < 100 > in-plane directions. The associated strain fields and or compositional ordering from these defects introduced a reduction in crystal symmetry that influenced the magnetic properties. The in-plane and perpendicular FMR anisotropies are not well described by bulk and interface contributions. In thick films, the in-plane uniaxial and fourfold anisotropies increased with increasing film thickness. The lattice defects resulted in a large extrinsic magnetic damping caused by two-magnon scattering, an increase in the coersive field with increasing film thickness, and a lower magnetic moment (3.6 Bohr magnetons) compared to the expected value for the bulk crystals (4 Bohr magnetons). (C) 2005 American Institute of Physics.
Quantum Geometry of Refined Topological Strings
Creators: name: Aganagic, Mina
name: Cheng, Miranda C. N.
name: Dijkgraaf, Robbert
name: Krefl, Daniel
name: Vafa, Cumrun
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We consider branes in refined topological strings. We argue that their wave-functions satisfy a Schrödinger equation depending on multiple times and prove this in the case where the topological string has a dual matrix model description. Furthermore, in the limit where one of the equivariant rotations approaches zero, the brane partition function satisfies a time-independent Schroedinger equation. We use this observation, as well as the back reaction of the brane on the closed string geometry, to offer an explanation of the connection between integrable systems and N=2 gauge systems in four dimensions observed by Nekrasov and Shatashvili.
description: 64 pages, 2 figures
Comparison of frequency, field, and time domain ferromagnetic resonance methods
Creators: name: Neudecker, I.
name: Woltersdorf, Georg
name: Heinrich, B.
name: Okuno, T.
name: Gubbiotti, G.
name: Back, Christian
Publisher: name: Universität Regensburg
Year: 2006
Subjects: subject: Ferromagnetic resonance; VNA-FMR; Ultrathin films; Permalloy disks
subject: 530 Physik

description: We present vector network analyzer ferromagnetic resonance measurements of epitaxial Fe films having a thickness of 16 monolayers. Our objective is to test the reliability of this novel frequency domain technique with respect to frequency and damping. For this purpose we compare vector network analyzer ferromagnetic resonance to pulsed inductive microwave magnetometry, time resolved magnetooptic Kerr effect (both methods in the time domain), and conventional ferromagnetic resonance (measured in the field domain) in terms of position and width of the ferromagnetic resonance. In addition, we compare the various techniques with respect to the signal to noise ratio of the raw data. All data is obtained using the same well characterized ultrathin magnetic Fe/GaAs (0 0 1) film. Finally, we demonstrate the potential of the vector network analyzer ferromagnetic resonance technique for the investigation of nano-structured magnetic elements having nonuniform magnetization configuration. The absorption spectrum of Permalloy disks with a diameter of 200 nm and a thickness of 15 nm shows up to eight distinct resonance peaks. The spatial structure of the corresponding modes was derived from numerical calculations and reveals that azimuthal modes up to the fifth order have been observed inductively. (c) 2006 Elsevier B.V. All rights reserved.
Dialogue about Syllabus for Education of Research Methods in Journalism and Communication: A Contract, a Plan, a Cognitive Map, or a Communication Device?
Creators: name: Xie, Ming
name: Chao, Chin-Chung
Publisher: name: AEJMC
Year: 2023

description: This study explores how the teaching of research methods in journalism and communication is embodied through syllabi in U.S. classrooms. Through emails and an online search, this study collects and reviews syllabi from the 102 accredited programs by Accrediting Council on Education in Journalism and Mass Communications. Based on four major distinct purposes of a syllabus —as a contract, a communication device, a plan, and a cognitive map—we examined the current education status of research methods courses and identified strategies of using syllabi as a learner-centered tool which can empower students to be motivated and self-directed learners
Recycling precious metals from mobile phones
Creators: name: Aquino, Sergio
Publisher: name: University of British Columbia
Year: 2018

description: The world population reached 7.5 billion inhabitants in April 2017. The number of mobile phones will reach 4.77 billion by the end of this year. Mobile phones are made of more than 50 elements. Discoveries of economically viable gold mines in the main producing countries have been slowing down significantly since the 1800s. The global surface temperature of the planet is warming at 0.17⁰C per decade relative to pre-industrial levels. The mobile phone was chosen for this thesis because it is a comprehensive unit of hazardous waste and e-waste. Mobile phones are a municipal solid waste and public health concern. The low energy and low barrier to entry recycling business this thesis envisions recycles precious metals from end of life mobile phones close to where the devices are discarded. This thesis uses system dynamics to model the exponential adoption of mobile phones and its impact in mining and CO₂e emissions. The model is the basis to calculate the return of new precious metal recycling businesses. Climate change is one of the hardest problem men has ever faced because it requires many countries to work together to establish climate centric governance and policies. Businesses are reviewing their supply chain and energy sources. This work focuses on disruptive low energy and low barrier to entry technologies to recycle precious metals from mobile phones. Local recycling businesses will create jobs and stimulate the economy in B.C., Canada, and the world.
Vortex dynamics in Permalloy disks with artificial defects: Suppression of the gyrotropic mode
Creators: name: Kuepper, K.
name: Bischoff, L.
name: Akhmadaliev, Ch.
name: Fassbender, J.
name: Stoll, H.
name: Chou, K. W.
name: Puzic, A.
name: Fauth, K.
name: Dolgos, D.
name: Schuetz, G.
name: Van Waeyenberge, B.
name: Tyliszczak, T.
name: Neudecker, I.
name: Woltersdorf, Georg
name: Back, Christian H.
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik

description: The dynamics of magnetic vortices in thin Permalloy disks having artificial defects in the form of small holes at different locations within the disk has been investigated by means of frequency-domain spatially resolved ferromagnetic resonance. It is found that the vortex can be effectively captured by such a defect. Consequently the commonly observed gyrotropic vortex motion in an applied microwave field of 1 mT is suppressed. However, if in addition a static magnetic field of at least 4.3 mT is applied, the vortex core is nucleated from the artificial defect and a modified gyrotropic motion starts again. (c) 2007 American Institute of Physics.
Review of Nancy Yousef's The Aesthetic Commonplace: Eliot, Wittgenstein and the Language of Every Day
Creators: name: Van Den Broek, A. G.
Publisher: name: George Eliot Review Online
Year: 2023
Subjects: Biography

description: Article from the George Eliot Review. Digitized and hosted by the George Eliot Review Online, editor Beverley Park Rilett.
The targum (1879:May)
Creators: name: No Name Supplied
Publisher: name: Targum Association
Year: 1879

description: Some University historians indicate that the Targum was first published as an annual in 1867, but of this we have no extant evidence. In January 1869, the Targum as we now know it, made its appearance as a monthly paper that concerned itself with student “literary contributions” and college news as well as serving as a vehicle for bringing news to alumni and the general public. The newspaper, which originally was for sale, varied in frequency over the years as did its title (The Targum, Rutgers Targum, Rutgers Daily Targum, and Daily Targum). The newspaper has continuously been published since 1869 with the exception of 19 months during the second world war, between February 1944 and October 1945. The Targum was published by the students of Rutgers College, and later Rutgers University—New Brunswick represented through the years as the Targum Association, Rutgers Targum Association, and Rutgers College Targum. As a student organization, the Targum operated under the oversight of the dean of students and student government but in October 1980, the Targum became an independent college paper.
An investigation into the controls and variability of the flowback water inorganic geochemistry of the Montney Formation, Northeastern British Columbia and Northwestern Alberta, Canada
Creators: name: Owen, Jennifer Nicole
Publisher: name: University of British Columbia
Year: 2018

description: The Montney Formation is the principal unconventional hydrocarbon reservoir currently being developed in Canada. The flowback water from 31 wells located on 9 well pads was sampled over time and analyzed for major ions, key minor ions, and δ¹⁸O and δ²H isotopes. The injected hydraulic fracturing fluids and produced waters, if available, were analyzed for the same parameters. The results of the study are used to compare the flowback water chemistry between wells and investigate the variables that have a significant influence on the chemistry. When comparing the flowback water chemistry between multiple wells, consideration must be given to the length of the flowback period, as the major ion concentrations typically increase over time. The dominant influence on the increasing concentrations is mixing between hydraulic fracturing fluid and formation water. Cl and stable water isotopes were used as conservative tracers to calculate the increasing proportions of formation water. These proportions were used with geochemical models to determine that mixing explains the Na and K concentrations, while mixing with ion exchange is influencing Ca, Mg, and Sr concentrations. Sulfate concentrations are influenced by pyrite oxidation and sulfate reduction. The rate of increase of the major ions varies between wells, although it is often, but not always, similar between wells completed at the same site, due to similarities in reservoir properties and well completion. The inconsistency is due to the many variables that may impact the flowback water chemistry. A multiple regression analysis identified shut-in time as an important variable, with longer shut-in correlating to higher concentrations. The chemistry of hydraulic fracturing fluids and formation waters were found to be important variables for some ions. The minor ions included in the study are Ba, B, and Li. Ba concentrations are likely related to barite dissolution/precipitation and are highest where sulfate concentrations are low. B and Li concentrations are both dominantly influenced by mixing and may vary due to differences in formation water chemistry. Overall, the results are expected to contribute to the growing knowledge on flowback water chemistry and its use in investigating the processes occurring in the reservoir during hydraulic fracturing.
Dual fast-cycling superconducting synchrotron at Fermilab and a possible path to the future of high energy particle physics
Creators: name: Piekarz, H.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: We briefly outline shorter and longer term physics motivation for constructing a dual, fast-cycling superconducting synchrotron accelerator (DSFMR - Dual Super-Ferric Main Ring) in the Tevatron tunnel at Fermilab. We discuss using this accelerator as a high-intensity dual neutrino beam source for the long-baseline neutrino oscillation search experiments, and also as a fast, dual pre-injector accelerator for the VLHC (Very Large Hadron Collider).
Microwave assisted switching of single domain Ni80Fe20 elements
Creators: name: Woltersdorf, Georg
name: Back, Christian H.
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik
subject: 75.60.Jk
subject: 75.30.Ds
subject: 75.75.+a
subject: 78.47.+p

description: We study the switching behavior of thin single domain magnetic elements in the presence of microwave excitation. The application of a microwave field strongly reduces the coercivity of the elements. We show that this effect is most profound at the ferromagnetic resonance frequency of the elements. Observations using time-resolved magneto-optic Kerr microscopy in combination with pulsed microwave excitation further support that the microwave assisted switching process is indeed based on the coherent motion of the magnetization.
Laser-Induced Magnetization Dynamics of Lanthanide-Doped Permalloy Thin Films
Creators: name: Radu, I.
name: Woltersdorf, Georg
name: Kiessling, M.
name: Melnikov, A.
name: Bovensiepen, U.
name: Thiele, J.-U.
name: Back, Christian H.
Publisher: name: Universität Regensburg
Year: 2009
Subjects: subject: 530 Physik
subject: 75.40.Gb
subject: 76.50.+g

description: We investigate the effect of Ho, Dy, Tb, and Gd impurities on the femtosecond laser-induced magnetization dynamics of thin Permalloy films using the time-resolved magneto-optical Kerr effect. Varying the amount of Ho, Dy, Tb content from 0% to 8%, we observe a gradual change of the characteristic demagnetization time constant from approximate to 60 to approximate to 150 fs. In contrast, Gd concentrations up to 15% do not influence the time scale of the initial photoinduced magnetization loss. We propose a demagnetization mechanism that relies on strong magnetic inertia of the rare-earth dopant which stabilizes the ferrimagnetic ordering and thereby delays the demagnetization.
Magnetic anisotropies in ultrathin iron films grown on the surface-reconstructed GaAs substrate
Creators: name: Aktas, B.
name: Heinrich, B.
name: Woltersdorf, G.
name: Urban, R.
name: Tagirov, L. R.
name: Yildiz, F.
name: Oezdogan, K.
name: Oezdemir, M.
name: Yalcin, O.
name: Rameev, B. Z.
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik

description: Magnetic anisotropies of epitaxial ultrathin iron films grown on the surface-reconstructed GaAs substrate were studied. Ferromagnetic resonance technique was exploited to determine magnetic parameters of the films in the temperature range of 4-300 K. Extraordinary angular dependence of the FMR spectra was explained by the presence of fourfold and twofold in-plane anisotropies. A strong in-plane uniaxial anisotropy with magnetic hard axis along the [1 (1) over bar0] crystallographic direction is present at the GaAs/Fe(001) interface while a weak in-plane uniaxial anisotropy for the Fe grown on Au has its easy axis oriented along [1 (1) over bar0]. A linear dependence of the magnetic anisotropies as a function of temperature suggests that the strength of the in-plane uniaxial anisotropy is affected by the magnetoelastic anisotropies and differential thermal expansion of contacting materials. (c) 2007 American Institute of Physics.
Supplementary material from Differences in the biochemical content and radical scavenging activity of propolis from different parts of a Meliponula ferruginea hive
Creators: name: Kegode, Timothy M.
name: Mokaya, Hosea O.
name: Solomon, Chogo
name: Noiset, Pierre
name: Vereecken, Nicolas J.
name: Tamiru, Amanuel
name: Subramanian, Sevgan
name: Kiatoko, Nkoba
Publisher: name: The Royal Society
Year: 2023
Subjects: classificationCode: 310199
subject: Biochemistry and cell biology not elsewhere classified
classificationCode: 340199
subject: Analytical chemistry not elsewhere classified

description: Research on stingless bee products has increased in recent years, and of particular interest is propolis because of its biological activities such as antioxidant and antimicrobial. However, there is paucity of information regarding intra-hive variations in the biochemical composition and biofunctional properties of this propolis. In this study, we investigated the phytochemicals and radical scavenging activity (RSA) of Meliponula ferruginea propolis from 10 wooden hives (n = 49). The samples were collected from five different locations comprising the entrance, involucrum, pillars, pots and sealant. Principal component analysis (PCA) showed that there is an intra-hive variation in phytochemical content and RSA. Phenolic content constituted the highest phytochemical content in all the locations. The sealant and entrance had the highest amounts of phytochemicals compared to the involucrum, pillars and pots. Further analysis of propolis extracts by gas chromatography-mass spectrometry revealed occurrence of different compounds such as monoterpenoids, hydrocarbons, triterpenoids and alkaloids. Hydrocarbons were common in all parts while monoterpenes and triterpenes were present in the entrance. The findings of our study indicates that there is an intra-hive variation in propolis of M. ferruginea and hence this information will provide further insight into better understanding of stingless bee propolis.
Relativistic accelerating electromagnetic waves
Creators: name: Hacyan, Shahen
Publisher: name: arXiv
Year: 2011
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: An exact solution of the Maxwell equations in Rindler coordinates is obtained. The electromagnetic field represents a wave preserving its shape in a relativistic uniformly accelerated frame. The relation with Airy beams is shown explicitly in the non-relativistic limit.
Open Science Presentation at the 2019 Nanofront Winter Retreat
Creators: name: Steele, Gary
Publisher: name: Zenodo
Year: 2019
Subjects: Open Science

description: An after-dinner presentation I gave about the topic of Open Science to the NanoFront Winter Retreat 2019 in Courchevel, France, with the aim of stimulating awareness, discussion, and dialogue about open science.
Microstrip line ferromagnetic resonance and Brillouin light scattering investigations of magnetic properties of Co2MnGe Heusler thin films
Creators: name: Belmeguenai, M.
name: Zighem, F.
name: Roussigne, Y.
name: Chérif, S.-M.
name: Moch, P.
name: Westerholt, K.
name: Woltersdorf, Georg
name: Bayreuther, Günther
Publisher: name: Universität Regensburg
Year: 2009
Subjects: subject: 530 Physik
subject: 76.50.+g
subject: 78.35.+c
subject: 75.30.Gw
subject: 75.40.Gb

description: Co2MnGe films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at 400 degrees C on single-crystal Al2O3 corundum substrates showing an in-plane c axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and planar anisotropy axes at +/-pi/4 of the c axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the planar anisotropy axes is parallel to c and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.
The targum (1878:Mar.)
Creators: name: No Name Supplied
Publisher: name: Targum Association
Year: 1878

description: Some University historians indicate that the Targum was first published as an annual in 1867, but of this we have no extant evidence. In January 1869, the Targum as we now know it, made its appearance as a monthly paper that concerned itself with student “literary contributions” and college news as well as serving as a vehicle for bringing news to alumni and the general public. The newspaper, which originally was for sale, varied in frequency over the years as did its title (The Targum, Rutgers Targum, Rutgers Daily Targum, and Daily Targum). The newspaper has continuously been published since 1869 with the exception of 19 months during the second world war, between February 1944 and October 1945. The Targum was published by the students of Rutgers College, and later Rutgers University—New Brunswick represented through the years as the Targum Association, Rutgers Targum Association, and Rutgers College Targum. As a student organization, the Targum operated under the oversight of the dean of students and student government but in October 1980, the Targum became an independent college paper.
Magnetic properties of NiMnSb(001) films grown on InGaAs/InP(001)
Creators: name: Heinrich, B.
name: Woltersdorf, Georg
name: Urban, R.
name: Mosendz, O.
name: Schmidt, G.
name: Bach, P.
name: Molenkamp, L.
name: Rozenberg, E.
Publisher: name: Universität Regensburg
Year: 2004
Subjects: subject: manganese alloys, antimony alloys, nickel alloys, molecular beam epitaxial growth, ferromagnetic materials, ferromagnetic resonance, damping, magnetic epitaxial layers, magnetic anisotropy, g-factor, spin-orbit interactions, magnons
subject: 530 Physik
subject: 75.30.Gw
subject: 75.30.Ds
subject: 75.50.Cc
subject: 76.50.+g
subject: 75.70.Ak

description: NiMnSb half Heusler alloy films were prepared by molecular beam epitaxy (MBE) on InP(001). The dc and rf magnetic properties were investigated by ferromagnetic resonance (FMR). The effective uniaxial anisotropy fields increased with increasing film thickness and reached nonzero asymptotic values. FMR linewidths rapidly increased with the film thickness due to the presence of two magnon scattering. Bulklike uniaxial anisotropies and two magnon scattering were caused by a self-assembled network of lattice defects. Gilbert damping parameter and spectroscopic g factor were found to be 3.1x10(7) and 2.03, respectively, indicating a weak role of spin orbit interaction. (C) 2004 American Institute of Physics.
The modes of gold loss in the calcium thiosulfate leaching system
Creators: name: Daenzer, Renaud
Publisher: name: University of British Columbia
Year: 2018

description: The processing of gold is becoming more complicated due to the increasingly complex nature of the remaining gold-bearing ore bodies. This worldwide phenomenon is the driving force for the development of alternative technologies for the leaching and recovery of gold from so-called double refractory ores. Barrick Gold recently commercialized a unique calcium thiosulfate leaching plant to treat these problematic ores after an autoclave pre-treatment with simultaneous recovery of the dissolved gold-thiosulfate complex onto anion exchange resins. Nonetheless, this new process can experience unexpected losses in gold from solution. It is hypothesized that the reagent’s degradation products known as polythionates and various mineral additions could adversely affect soluble gold stability along with their known detrimental effect on gold recovery. This dissertation aims to understand the possible causes of gold losses by means of a thorough investigation of the effects of polythionate and mineral additions into synthetic calcium thiosulfate leaching solutions. A series of batch leaching experiments were subsequently conducted on actual preg-robbing ores to further elucidate the effects of polythionates on the stability soluble gold complexes in the calcium thiosulfate system. A subsequent study on the rates of polythionate species loading on the resin and their competitive loading behaviour was made and extended to include their effects on the displacement of gold from the resin. This was demonstrated in the form of gold loading isotherms tailored to the calcium thiosulfate leaching system. Ultimately, the processes of gold leaching from refractory ores and gold recovery by resin loading in the presence of polythionates were tied together in a last study to quantify their harmful outcomes on overall gold extraction.
Size distribution and waiting times for the avalanches of the Cell Network Model of Fracture
Creators: name: Villalobos, Gabriel
name: Kun, Ferenc
name: Linero, Dorian L.
name: Muñoz, Jose D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computational Physics (physics.comp-ph)
subject: Cell Behavior (q-bio.CB)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: The Cell Network Model is a fracture model recently introduced that resembles the microscopical structure and drying process of the parenchymatous tissue of the Bamboo Guadua angustifolia. The model exhibits a power-law distribution of avalanche sizes, with exponent -3.0 when the breaking thresholds are randomly distributed with uniform probability density. Hereby we show that the same exponent also holds when the breaking thresholds obey a broad set of Weibull distributions, and that the humidity decrements between successive avalanches (the equivalent to waiting times for this model) follow in all cases an exponential distribution. Moreover, the fraction of remaining junctures shows an exponential decay in time. In addition, introducing partial breakings and cumulative damages induces a crossover behavior between two power-laws in the avalanche size histograms. This results support the idea that the Cell Network Model may be in the same universality class as the Random Fuse Model.
Intrinsic spin relaxation processes in metallic magnetic multilayers
Creators: name: Heinrich, B.
name: Woltersdorf, Georg
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik

description: Spin relaxation processes in metallic magnetic nanostructures are reviewed. First a brief review of the phenomenology of magnetic damping is presented using the Landau Lifshitz Gilbert (LLG) equations of motion. It is shown that the Gilbert damping in bulk metallic layers is caused by the spin orbit interaction and itinerant character of 3d and 4s-p electrons. Spin dynamics in magnetic nanostructures acquires an additional nonlocal damping. This means that a part of the magnetic damping is not given by the local Gilbert damping but arises from the proximity to other layers. Spin pumping and spin sink concepts will be introduced and used to describe the interface nonlocal Gilbert damping in magnetic multilayers. The modified LLG equation of motion in magnetic multilayers will be introduced and tested against the ferromagnetic resonance (FMR) data around the accidental crossover of FMR fields. The spin pumping theory will be compared to the early theories introduced in the 1970s for the interpretation of transmission electron spin resonance (TESR) measurements across ferromagnet/normal metal sandwiches.
Magnetization dynamics due to pure spin currents in magnetic double layers
Creators: name: Woltersdorf, Georg
name: Mosendz, O.
name: Heinrich, B.
name: Back, Christian H.
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik
subject: 72.25.−b
subject: 75.40.Gb
subject: 78.47.+p
subject: 78.67.Pt

description: The magnetization dynamics in magnetic double layers is affected by spin-pump and spin-sink effects. So far, only the spin pumping and its effect on the magnetic damping has been studied. However, due to conservation of angular momentum this spin current also leads to magnetic excitation of the layer dissipating this angular momentum. In this Letter we use time resolved magneto-optic Kerr effect to directly show the excitation due to the pure spin current. In particular, we observe magnetization dynamics due to transfer of angular momentum in magnetic double layers. In contrast to other experiments where a spin polarized charge current is passed through a nanomagnet, the effects discussed in this Letter are based on pure spin currents without net transfer of electric charge.