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Proton

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Full-Text Articles in Physical Sciences and Mathematics

Quark Spin-Orbit Correlations In The Proton, M. Engelhardt, J. Green, N. Hasan, T. Izubuchi, C. Kallidonis, S. Krieg, S. Liuti, S. Meinel, J. Negele, A. Pochinsky, A. Rajan, G. Silvi, S. Syritsyn Jan 2022

Quark Spin-Orbit Correlations In The Proton, M. Engelhardt, J. Green, N. Hasan, T. Izubuchi, C. Kallidonis, S. Krieg, S. Liuti, S. Meinel, J. Negele, A. Pochinsky, A. Rajan, G. Silvi, S. Syritsyn

Physics Faculty Publications

Generalized transverse momentum-dependent parton distributions (GTMDs) provide a comprehensive framework for imaging the internal structure of the proton. In particular, by encoding the simultaneous distribution of quark transverse positions and momenta, they allow one to directly access longitudinal quark orbital angular momentum, and, moreover, to correlate it with the quark helicity. The relevant GTMD is evaluated through a lattice calculation of a proton matrix element of a quark bilocal operator (the separation in which is Fourier conjugate to the quark momentum) featuring a momentum transfer (which is Fourier conjugate to the quark position), as well as the Dirac structure appropriate …


Cooling Performance In A Dual Energy Storage Ring Cooler, B. Dhital, Y. S. Derbenev, D. Douglas, G. A. Krafft, H. Zhang, F. Lin, V. S. Morozov, Y. Zhang Jan 2022

Cooling Performance In A Dual Energy Storage Ring Cooler, B. Dhital, Y. S. Derbenev, D. Douglas, G. A. Krafft, H. Zhang, F. Lin, V. S. Morozov, Y. Zhang

Physics Faculty Publications

The longitudinal and transverse emittance growth in hadron beams due to intra-beam scattering (IBS) and other heating sources deteriorate the luminosity in a collider. Hence, a strong hadron beam cooling is required to reduce and preserve the emittance. The cooling of high energy hadron beam is challenging. We propose a dual energy storage ring-based electron cooler that uses an electron beam to extract heat away from hadron beam in the cooler ring while the electron beam is cooled by synchrotron radiation damping in the high energy damping ring. In this paper, we present a design of a dual energy storage …


High Frequency Percussive Ventilation For Tumor Motion Immobilization, Ina Marina Sala Jan 2019

High Frequency Percussive Ventilation For Tumor Motion Immobilization, Ina Marina Sala

Wayne State University Dissertations

This work investigates the use of High Frequency Percussive Ventilation as a technique for respiratory motion mitigation in radiotherapy. This technique was extensively investigated in several prospective and retrospective studies.

In an initial prospective study, we evaluated the feasibility of HFPV and chest-wall motion reduction, by recruiting 15 healthy volunteers to undergo HFPV with three commercially available interfaces. For direct tumor motion immobilization, a second prospective study was performed in which with ten lung cancer patients underwent HFPV while imaged with high frame rate fluoroscopy. Diaphragm motion and image artifacts were quantified in a prospective study of a healthy volunteer …


The Us Electron Ion Collider Accelerator Designs, A. Seryi, S.V. Benson, S.A. Bogacz, P.D. Brindza, M.W. Brucker, A. Camsonne, E. Daly, P.V. Degtiarenko, Y.S. Derbenev, M. Diefenthaler, J. Dolbeck, R. Ent, R. Fair, D. Fazenbaker, Y. Furletova, B.R. Gamage, D. Gaskell, R.L. Geng, P. Ghoshal, R.C. York, Et Al. Jan 2019

The Us Electron Ion Collider Accelerator Designs, A. Seryi, S.V. Benson, S.A. Bogacz, P.D. Brindza, M.W. Brucker, A. Camsonne, E. Daly, P.V. Degtiarenko, Y.S. Derbenev, M. Diefenthaler, J. Dolbeck, R. Ent, R. Fair, D. Fazenbaker, Y. Furletova, B.R. Gamage, D. Gaskell, R.L. Geng, P. Ghoshal, R.C. York, Et Al.

Physics Faculty Publications

With the completion of the National Academies of Sciences Assessment of a US Electron-Ion Collider, the prospects for construction of such a facility have taken a step forward. This paper provides an overview of the two site-specific EIC designs: JLEIC (Jefferson Lab) and eRHIC (BNL) as well as brief overview of ongoing EIC R&D.


Polarized Hyperon Production In Single-Inclusive Electron Positron Annihilation At Next-To-Leading Order, Leonard Gamberg, Zhong-Bo Kang, Daniel Pitonyak, Marc Schlegel, Shinsuke Yoshida Jan 2019

Polarized Hyperon Production In Single-Inclusive Electron Positron Annihilation At Next-To-Leading Order, Leonard Gamberg, Zhong-Bo Kang, Daniel Pitonyak, Marc Schlegel, Shinsuke Yoshida

Physics Faculty Publications

We study the production of polarized A-hyperons in electron-positron annihilation. We are particularly interested in the transverse-spin dependence of the cross section for unpolarized incident electron-positron pairs. At high energies this process may be described in the collinear twist-3 framework, where the hadronization transition of partons into a transversely polarized -hyperon can be written in terms of collinear twist-3 fragmentation matrix elements. We calculate the hard partonic cross sections and interference terms in perturbative QCD to next-to-leading order accuracy. We find that the QCD equation of motion plays a crucial role in our analysis. As a byproduct, assuming the validity …


Photoproduction Of K+ K- Meson Pairs On The Proton, S. Lombardo, M. Battaglieri, A. Celentano, A. D'Angelo, R. De Vita, A. Filippi, D. I. Glazier, M. Khachatryan, A. Klein, Y. Prok, The Clas Collaboration Sep 2018

Photoproduction Of K+ K- Meson Pairs On The Proton, S. Lombardo, M. Battaglieri, A. Celentano, A. D'Angelo, R. De Vita, A. Filippi, D. I. Glazier, M. Khachatryan, A. Klein, Y. Prok, The Clas Collaboration

Physics Faculty Publications

The exclusive reaction γp → pK+K was studied in the photon energy range 3.0–3.8 GeV and momentum transfer range 0.6 < −t< 1.3 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range the integrated luminosity was approximately 20 pb−1. The reaction was isolated by detecting the K+ and the proton in CLAS, and reconstructing the K via the missing-mass technique. Moments of the dikaon decay angular distributions were extracted from the experimental data. Besides the dominant contribution of the ϕ meson in the P wave, …


Asymmetric Relativistic Fermi Gas Model For Quasielastic Lepton-Nucleus Scattering, M. B. Barbaro, A. De Pace, T. W. Donnelly, J. A. Caballero, G. D. Megias, J. W. Van Orden Sep 2018

Asymmetric Relativistic Fermi Gas Model For Quasielastic Lepton-Nucleus Scattering, M. B. Barbaro, A. De Pace, T. W. Donnelly, J. A. Caballero, G. D. Megias, J. W. Van Orden

Physics Faculty Publications

We develop an asymmetric relativistic Fermi gas model for the study of the electroweak nuclear response in the quasielastic region. The model takes into account the differences between neutron and proton densities in asymmetric (N> Z) nuclei, as well as differences in the neutron and proton separation energies. We present numerical results for both neutral and charged-current processes, focusing on nuclei of interest for ongoing and future neutrino oscillation experiments. We point out some important differences with respect to the commonly employed symmetric Fermi gas model.


Addressing The Proton Radius Puzzle Using Qed-Nrqed Effective Field Theory, Steven Patrick Dye Jan 2018

Addressing The Proton Radius Puzzle Using Qed-Nrqed Effective Field Theory, Steven Patrick Dye

Wayne State University Dissertations

In 2010 the first extraction of the proton charge radius from muonic hydrogen was found to be five standard deviations away from the regular hydrogen value. Seven years later, this proton radius puzzle still persists, and challenges our understanding of the structure of the proton. An effective field theory analysis using Non-Relativistic Quantum Electrody- namics (NRQED) indicates that the muonic hydrogen result can be interpreted as a large, compared to some model estimates, muon-proton spin-independent contact interaction. The muonic hydrogen result can be tested by a muon-proton scattering experiment, MUSE, that is planned at the Paul Scherrer Institute in Switzerland. …


Measurements Of Differential Cross Sections For Associated Production Of A W Boson And Jets In Proton-Proton Collisions At Square Root Of S = 8 Tev, A. M. Sirunyan, A. R. Tumasyan, W. Adam, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva Oct 2017

Measurements Of Differential Cross Sections For Associated Production Of A W Boson And Jets In Proton-Proton Collisions At Square Root Of S = 8 Tev, A. M. Sirunyan, A. R. Tumasyan, W. Adam, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

A measurement of the differential cross sections for a W boson produced in association with jets in the muon decay channel is presented. The measurement is based on 13 TeV proton-proton collision data corresponding to an integrated luminosity of 2.2 fb-1, recorded by the CMS detector at the LHC. The cross sections are reported as functions of jet multiplicity, jet transverse momentum pT, jet rapidity, the scalar pT sum of the jets, and angular correlations between the muon and each jet for different jet multiplicities. The measured cross sections are in agreement with predictions that include multileg leading-order (LO) and …


Studying The Reaction 34ar(Alpha,P)37k And Its Impact On Xrb Nucleosynthesis And Observables, Amber C. Lauer Oct 2017

Studying The Reaction 34ar(Alpha,P)37k And Its Impact On Xrb Nucleosynthesis And Observables, Amber C. Lauer

LSU Doctoral Dissertations

Type I X-Ray bursts (XRB’s) are a site of nucleosynthesis for some proton-rich elements up to A=100. These stellar explosions occur on the surface of a neutron star in a Low- Mass X-ray Binary accreting H- and He-rich material. During accretion nuclear burning occurs through stable processes such as the hot CNO (HCNO) cycles, but at some critical accretion condition the the HCNO cycles are bypassed through a breakout reaction. This triggers the thermonuclear runaway of the XRB. During the burst, nucleosynthesis on certain proton-rich nuclei, called (α, p) waiting points, can stall which could stall the energy generation and …


Radiation Therapy Medical Physics Review – Delivery, Interactions, Safety, Feasibility, And Head To Head Comparisons Of The Leading Radiation Therapy Techniques, Cielle Collins Jan 2017

Radiation Therapy Medical Physics Review – Delivery, Interactions, Safety, Feasibility, And Head To Head Comparisons Of The Leading Radiation Therapy Techniques, Cielle Collins

Honors Theses and Capstones

Radiation therapy uses high energy radiation to kill cancer cells. Radiation therapy for cancer treatment can take the form of photon therapy (using x-rays and gamma rays), or charged particle therapy including proton therapy and electron therapy. Within these categories, numerous methods of delivery have been developed. For example, a certain type of radiation can be administered by a machine outside of the body, called external-beam radiation therapy, or by a “seed” placed inside of the body near cancer cells, called internal radiation therapy or brachytherapy. Approximately half of all cancer patients receive radiation therapy, and the form of radiation …


Measurement Of New Observables From The Π + Π - Electroproduction Off The Proton, Arjun Trivedi Jan 2016

Measurement Of New Observables From The Π + Π - Electroproduction Off The Proton, Arjun Trivedi

Theses and Dissertations

Knowledge of the Universe as constructed by human beings, in order to tackle its complexity, can be thought to be organized at varying scales at which it is observed. Implicit in such an approach is the idea of a smooth evolution of knowledge between scales and, therefore, access to how Nature constructs the visible Universe beginning from its most fundamental constituents. New and, in a sense, fundamental phenomena may typically be emergent as the scale of observation changes. The study of the Strong Interaction, which is responsible for the construction of the bulk of the visible matter in the Universe …


Precision Measurement Of The Longitudinal Double-Spin Asymmetry For Inclusive Jet Production In Polarized Proton Collisions At √S=200 Gev, James K. Adkins, Renee H. Fatemi, Suvarna Ramachandran, Grant D. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer Aug 2015

Precision Measurement Of The Longitudinal Double-Spin Asymmetry For Inclusive Jet Production In Polarized Proton Collisions At √S=200 Gev, James K. Adkins, Renee H. Fatemi, Suvarna Ramachandran, Grant D. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer

Physics and Astronomy Faculty Publications

We report a new measurement of the midrapidity inclusive jet longitudinal double-spin asymmetry, ALL, in polarized pp collisions at center-of-mass energy √s=200  GeV. The STAR data place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep-inelastic scattering (DIS), semi-inclusive DIS, and RHIC pp data. The measured asymmetries provide evidence at the 3σ level for positive gluon polarization in the Bjorken-x region x>0.05.


Diol-Mediated Versus Water-Mediated Proton Transfer Reactions, Angela Moses May 2015

Diol-Mediated Versus Water-Mediated Proton Transfer Reactions, Angela Moses

DePaul Discoveries

The triple-proton-transfer reactions of 8H-1,8-naphthyridin-2-one (8H-naph) have been investigated by employing different ab initio quantum mechanical methods. The proton transfer reactions studied were facilitated through an adjacent 1,3-propanediol molecule or two adjacent water molecules. Identical proton transfer reactions were studied using a model system of 8H-naph to investigate the validity of computational approaches that use model systems to study more complex systems. The solvent effects on the structures were investigated for comparison to the initial gas phase calculations. The potential energy, reaction force, and work profiles were studied along the intrinsic reaction coordinate to monitor the developing proton transfer reactions.


Direct Observation Of Quark-Hadron Duality In The Free Neutron F2 Structure Function, I. Niculescu, G. Niculescu, W. Melnitchouk, J. Arrington, M. E. Christy, S. Kuhn Jan 2015

Direct Observation Of Quark-Hadron Duality In The Free Neutron F2 Structure Function, I. Niculescu, G. Niculescu, W. Melnitchouk, J. Arrington, M. E. Christy, S. Kuhn

Physics Faculty Publications

Using the recently published data from the BONuS(Barely Off-shell Nucleon Structure) experiment at Jefferson Lab, which utilized a spectator tagging technique to extract the inclusive electron-free neutron scattering cross section, we obtain the first direct observation of quark-hadron duality in the neutron F2 structure function. The data are used to reconstruct the lowest few (N = 2, 4, and 6) moments of F2 in the three prominent nucleon resonance regions, as well as the moments integrated over the entire resonance region. Comparison with moments computed from global parametrizations of parton distribution functions suggest that quark-hadron duality holds locally …


A Comparative Study Of Gupix And Geopixe Software In The Analysis Of Pixe Spectra Of Aerosol Samples, Sean Collison Jun 2014

A Comparative Study Of Gupix And Geopixe Software In The Analysis Of Pixe Spectra Of Aerosol Samples, Sean Collison

Honors Theses

Proton-induced X-ray emission (PIXE) spectroscopy is a powerful tool used in the Union College Ion-Beam Analysis Laboratory for the elemental analysis of environmental pollution. Samples are bombarded with proton beams from the 1.1‐MV Pelletron accelerator and characteristic X-rays emitted from the samples are detected, resulting in X-ray energy spectra. These spectra are analyzed using software packages that fit the data and calculate the concentrations of elements in the samples. I have performed a comparative study of two of the most popular software packages, GUPIX and GeoPIXE, in the analysis of atmospheric aerosol samples to assess the strengths and weaknesses of …


Single Spin Asymmetries In Charged Kaon Production From Semi-Inclusive Deep Inelastic Scattering On A Transversely Polarized He-3 Target, Y. X. Zhao, Y. Wang, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, M. Canan Jan 2014

Single Spin Asymmetries In Charged Kaon Production From Semi-Inclusive Deep Inelastic Scattering On A Transversely Polarized He-3 Target, Y. X. Zhao, Y. Wang, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, M. Canan

Physics Faculty Publications

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized 3He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of0.1 < xbj < 0.4for K+ and K production. While the Collins and Sivers moments for K+ are consistent with zero within the experimental uncertainties, both moments for K favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While …


Employing Twin Crabbing Cavities To Address Variable Transverse Coupling Of Beams In The Meic, A. Castilla, V. S. Morozov, T. Satogata, J. R. Delayen Jan 2014

Employing Twin Crabbing Cavities To Address Variable Transverse Coupling Of Beams In The Meic, A. Castilla, V. S. Morozov, T. Satogata, J. R. Delayen

Physics Faculty Publications

The design strategy of the Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab contemplates both matching of the emittance aspect ratios and a 50 mrad crossing angle along with crab crossing scheme for both electron and ion beams over the energy range (√s=20-70 GeV) to achieve high luminosities at the interaction points (IPs). However, the desired locations for placing the crabbing cavities may include regions where the transverse degrees of freedom of the beams are coupled with variable coupling strength that depends on the collider rings’ magnetic elements (solenoids and skew quadrupoles). In this work we explore the feasibility of …


Detection Of Boronic Acids Through Excited-State Intramolecular Proton-Transfer Fluorescence, Matthew R. Aronoff, Brett Vanveller, Ronald T. Raines Oct 2013

Detection Of Boronic Acids Through Excited-State Intramolecular Proton-Transfer Fluorescence, Matthew R. Aronoff, Brett Vanveller, Ronald T. Raines

Brett VanVeller

Boronic acids are versatile reagents for the chemical synthesis of organic molecules. They and other boron-containing compounds can be detected readily by the interruption of the excited-state intramolecular proton transfer (ESIPT) of 10-hydroxybenzo[h]quinolone. This method is highly sensitive and selective, and useful for monitoring synthetic reactions and detecting boron-containing compounds on a solid support.


Understanding Hard Interaction In Qcd And The Search For The Gluon Spin Contribution To The Spin Of The Proton, Amaresh Datta May 2012

Understanding Hard Interaction In Qcd And The Search For The Gluon Spin Contribution To The Spin Of The Proton, Amaresh Datta

Open Access Dissertations

In the following discourse unpolarized cross sections and double helicity asymmetries of single inclusive positive and negative charged hadrons at mid-rapidity from p + p collisions at p s = 62:4 GeV are presented. Measurements for the transverse momentum range 1:0 < pT < 4:5 GeV/c are done with PHENIX detector at Relativistic Heavy-Ion Collider (RHIC) and are consistent with calculations based on perturbative quantum chromodynamics (pQCD) at next-to-leading order (NLO) in the strong coupling constant, s. Resummed pQCD calculations including terms with next-to-leading log (NLL) accuracy, yielding reduced theoretical uncertainties, also agree with the data. The double helicity asymmetry, sensitive at leading order to the gluon polarization in a momentum fraction range of 0:05


Proton Dose Calculations In Homogeneous Media, John Wesley Chapman, Jr. Jan 2012

Proton Dose Calculations In Homogeneous Media, John Wesley Chapman, Jr.

LSU Master's Theses

In this study, a proton pencil beam dose calculation algorithm was developed for a parallel, monoenergetic beam incident on a homogeneous water phantom. Fermi-Eyges theory (Eyges 1948) was used to transport pencil beams, and the characteristic width of elastic scatter events was modeled using the differential Moliere scattering power (Gottschalk 2010). The incorporation of this scattering power formalism allowed our model to account for multiple Coulomb scattering, single scattering, plural scattering, and rigorously accounted for material effects on scatter. Nonelastic nuclear interactions were incorporated into an additional pencil beam model. The attenuation of primary fluence due to nuclear events was …


Evaluation Of A Proton Pencil Bean Algorithm For Dose Calculations In Heterogenous Media, Nels C. Knutson Jan 2012

Evaluation Of A Proton Pencil Bean Algorithm For Dose Calculations In Heterogenous Media, Nels C. Knutson

LSU Master's Theses

Purpose: To develop an improved nuclear halo dose model of a pencil beam algorithm (PBA) for dose calculation of proton beams in heterogeneous media. Methods: The proton PBA consisted of a central axis term and an off axis term. The central axis term was determined from a central axis depth dose profile of a Monte Carlo simulated proton beam in water and was scaled by a mass stopping power ratio to account for other materials. The off axis term was determined from Fermi-Eyges scattering theory with material-dependent scattering powers to calculate the lateral spread of the proton beam in heterogeneous …


The Development And Implementation Of An Anthropomorphic Head Phantom For The Assessment Of Proton Therapy Treatment Procedures, Paige A. Summers Aug 2011

The Development And Implementation Of An Anthropomorphic Head Phantom For The Assessment Of Proton Therapy Treatment Procedures, Paige A. Summers

Dissertations & Theses (Open Access)

Proton therapy has become an increasingly more common method of radiation therapy, with the dose sparing to distal tissue making it an appealing option, particularly for treatment of brain tumors. This study sought to develop a head phantom for the Radiological Physics Center (RPC), the first to be used for credentialing of institutions wishing to participate in clinical trials involving brain tumor treatment of proton therapy. It was hypothesized that a head phantom could be created for the evaluation of proton therapy treatment procedures (treatment simulation, planning, and delivery) to assure agreement between the measured dose and calculated dose within …


Contextual Ontology Alignment Of Lod With An Upper Ontology: A Case Study With Proton, Prateek Jain, Peter Z. Yeh, Kunal Verma, Reymonrod G. Vasquez, Mariana Darnorva, Pascal Hitzler, Amit P. Sheth Jan 2011

Contextual Ontology Alignment Of Lod With An Upper Ontology: A Case Study With Proton, Prateek Jain, Peter Z. Yeh, Kunal Verma, Reymonrod G. Vasquez, Mariana Darnorva, Pascal Hitzler, Amit P. Sheth

Kno.e.sis Publications

The Linked Open Data (LOD) is a major milestone towards realizing the Semantic Web vision, and can enable applications such as robust Question Answering (QA) systems that can answer queries requiring multiple, disparate information sources. However, realizing these applications requires relationships at both the schema and instance level, but currently the LOD only provides relationships for the latter. To address this limitation, we present a solution for automatically finding schema-level links between two LOD ontologies – in the sense of ontology alignment. Our solution, called BLOOMS+, extends our previous solution (i.e. BLOOMS) in two significant ways. BLOOMS+ 1) uses a …


Bazr(0.8)Y(0.2)O(3-Delta)-Nio Composite Anodic Powders For Proton-Conducting Sofcs Prepared By A Combustion Method, Lei Bi, Emiliana Fabbri, Ziqi Sun, Enrico Traversa Jan 2011

Bazr(0.8)Y(0.2)O(3-Delta)-Nio Composite Anodic Powders For Proton-Conducting Sofcs Prepared By A Combustion Method, Lei Bi, Emiliana Fabbri, Ziqi Sun, Enrico Traversa

Australian Institute for Innovative Materials - Papers

BaZr0.8Y0.2O3-∂ (BZY)-NiO composite powders with different BZY-NiO weight ratios were prepared by a combustion method as anodes for proton-conducting solid oxide fuel cells (SOFCs). After heating to 1100°C for 6 h, the composite powders were made of a well-dispersed mixture of two phases, BZY and NiO. Chemical stability tests showed that the BZY-NiO anodic powders had good stability against CO2, whereas comparative tests under the same conditions showed degradation for BaCe0.7Zr0.1Y0.2O3-∂- NiO, which is at present the most used anode material for proton-conducting …


Implementation Of The Clas12 Htcc Into Gemc, Nathan A. Harrison Dec 2010

Implementation Of The Clas12 Htcc Into Gemc, Nathan A. Harrison

Master's Theses

No abstract provided.


Carbon Nanotube Architectures As Catalyst Supports For Proton Exchange Membrane Fuel Cells, Weimin Zhang, Peter Sherrell, Andrew I. Minett, Joselito M. Razal, Jun Chen Jan 2010

Carbon Nanotube Architectures As Catalyst Supports For Proton Exchange Membrane Fuel Cells, Weimin Zhang, Peter Sherrell, Andrew I. Minett, Joselito M. Razal, Jun Chen

Faculty of Science - Papers (Archive)

Catalyst support materials exhibit great influence on the performance and durability of proton exchange membrane (PEM) fuel cells. This minireview article summarises recent developments into carbon nanotube-based support materials for PEM fuel cells, including the membrane electrode assembly (MEA). The advantages of using CNTs to promote catalyst performance and stability, a perspective on research directions and strategies to improve fuel cell performance and durability are discussed. It is hoped that this mini-review will act as a conduit for future developments in catalyst supports and MEA design for PEM fuel cells.


Virtual Compton Scattering And Neutral Pion Electroproduction In The Resonance Region Up To The Deep Inelastic Region At Backward Angles, G. Laveissiere, N. Degrande, S. Jaminion, C. Jutier, L. Todor, G. E. Dodge, C. E. Hyde, K. Mccormick, P. E. Ulmer, L. B. Weinstein, Jefferson Lab Hall A Collaboration Jan 2009

Virtual Compton Scattering And Neutral Pion Electroproduction In The Resonance Region Up To The Deep Inelastic Region At Backward Angles, G. Laveissiere, N. Degrande, S. Jaminion, C. Jutier, L. Todor, G. E. Dodge, C. E. Hyde, K. Mccormick, P. E. Ulmer, L. B. Weinstein, Jefferson Lab Hall A Collaboration

Physics Faculty Publications

We have made the first measurements of the virtual Compton scattering (VCS) process via the H(e, e′p)γ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the W-dependence at fixed Q2=1 GeV2 and for the Q2 dependence at fixed W near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed Q2 dependence is smooth. The measured ratio of H(e, e′p)γ to H(e, e′p)π0 cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared …


Poly(Arylene Ether)S With Truly Pendant Benzene Sulfonic Acid Groups, Mohamed Moustafa Abdellatif Jan 2008

Poly(Arylene Ether)S With Truly Pendant Benzene Sulfonic Acid Groups, Mohamed Moustafa Abdellatif

Browse all Theses and Dissertations

A series of new sulfonated poly(arylene ether)s containing one sulfonic acid group, located on a pendant phenyl sulfonyl moiety, at every repeat unit was synthesized using 3-sulfonated-3', 5'-difluorophenyl Sulfone, 4, and a variety of bisphenols. A conventional nucleophilic aromatic substitution (NAS) was utilized for the homopolymerization and copolymerization reactions. Polymerization reactions of 4 in NMP at 180 °C provided the corresponding linear sulfonated poly(arylene ether)s, s-PAEs, with number average molecular weight, Mn, ranging from 10,000 to 38,000 Daltons. All of the polymers were characterized by 1H and 13C NMR spectroscopy, thermogravimetric analysis (TGA), and differential scanning …


Measurement Of Deeply Virtual Compton Scattering Beam-Spin Asymmetries, Clas Collaboration, H. Bagdasaryan, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde, H. G. Juengst, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, S. Tkachenko, L. B. Weinstein, J. Zhang Jan 2008

Measurement Of Deeply Virtual Compton Scattering Beam-Spin Asymmetries, Clas Collaboration, H. Bagdasaryan, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde, H. G. Juengst, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, S. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The beam-spin asymmetries in the hard exclusive electroproduction of photons on the proton (ep→epγ ) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (xB from 0.11 to 0.58, Q2 from 1 to 4.8  GeV2, −t from 0.09 to 1.8  GeV2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A ≃ asinϕ/(1+ccosϕ). This extensive set of data can thus be used to …