School of Natural Sciences and Mathematics

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Synthesis and Characterization of a Novel Fluorinated Bismaleimide via a Nucleophilic Addition-Elimination Reaction and its Polymeric Networks
(Royal Society of Chemistry, 1905-07-07) Wu, Jingbo; Xi, Yang; McCandless, Gregory T.; Kulikov, Oleg V.; Menon, Remya; Novak, Bruce M.; Wu, Jingbo; Xi, Yang; McCandless, Gregory T.; Kulikov, Oleg V.; Menon, Remya; Novak, Bruce M.
The commercially available octafluorocyclopentene (OFCP) as both a fluorinated building block and a linker has been successfully utilized to prepare a new fluorinated bismaleimide monomer OFCP-BMIvia a nucleophilic addition-elimination reaction. The resulting OFCP-BMI is characterized by 1H, 13C, 19F nuclear magnetic resonance (NMR) spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and high resolution mass spectrometry. The monomer OFCP-BMI reacts with a free radical initiator or self-cures to prepare its resins. No obvious glass transition temperature (Tg) below 260°C was observed for the self-curing resin suggesting that a highly cross-linked polymeric network was formed. The self-curing resin exhibits excellent thermal stability with the on-set weight loss temperature (Ton-setd) of 445°C and a 50% char yield at 800°C under a nitrogen atmosphere. The resin obtained by a free radical polymerization process exhibits less thermal stability and a lower char yield than the self-curing resin due to its lower cross-linking density. The self-curing resin exhibits a low dielectric constant (Dk = 2.5).
Search for New Phenomena in Final States with an Energetic Jet and Large Missing Transverse Momentum in pp Collisions at √s=8 TeV with the ATLAS Detector
(Springer New York LLC, 1905-07-07) Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Izen, Joseph M.; Leyton, Michael; Meirose, Bernhard; Namasivayam, Harisankar; Reeves, Kendall; ATLAS Collaboration; 250674117 (Izen, JM); 250674117 (Izen, JM); Izen, Joseph M.; Leyton, Michael; Meirose, Bernhard; Namasivayam, Harisankar; Reeves, Kendall
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb-1 of √S=8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with PT>120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between (Formula presened.)>150 GeV and (Formula presened.)>700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presented.
The 4-D Microgravity Method for Waterflood Surveillance: A Model Study for the Prudhoe Bay Reservoir, Alaska
(Society of Exploration Geophysicists, 1999-01) Hare, J. L.; Ferguson, John F.; Aiken, Carlos L. V.; Brady, J. L.; 67724342 (Aiken, CLV); Ferguson, J. F.; Aiken, Carlos L. V.
Forward and inverse gravity modeling is carried out on a suite of reservoir simulations of a proposed water injection on the Prudhoe Bay reservoir, Alaska. A novel surveillance technique is developed in which surface gravity observations are used to monitor the progress of a gas cap waterflood in the reservoir at 8200-ft depth. The results of the modeling showed that the inversion of time-lapse gravity data is a viable technique for monitoring reservoir gas cap waterfloods. Forward and inverse gravity modeling is carried out on a suite of reservoir simulations of a proposed water injection in the Prudhoe Bay reservoir, Alaska. A novel surveillance technique is developed in which surface gravity observations are used to monitor the progress of a gas cap waterflood in the reservoir at 8200-ft (2500-m) depth. This cost-effective method requires that high-precision gravity surveys be repeated over periods of years. Differences in the gravity field with time reflect changes in the reservoir fluid densities. Preliminary field tests at Prudhoe Bay indicates survey accuracy of 5-10 μGal can be achieved for gravity data using a modified Lacoste and Romberg 'G' type meter or Scintrex CG-3M combined with the NAVSTAR Global Positioning System (GPS). Forward gravity modeling predicts variations in surface measurements of 100 μGal after 5 years of water injection, and 180-250 μGal after 15 years. We use a constrained least-squares method to invert synthetic gravity data for subsurface density distributions. The modeling procedure has been formulated and coded to allow testing of the models for sensitivity to gravity sampling patterns, noise types, and various constraints on model parameters such as density, total mass, and moment of inertia. Horizontal-feature resolution of the waterflood is about 5000 ft (1520 m) for constrained inverse models from synthetic gravity with 5 μGal standard deviation (SD) noise. The inversion method can account for total mass of injected water to within a few percent. Worst-case scenarios result from inversion of gravity data which are contaminated by high levels (greater than 10-15 μGal SD) of spatially correlated noise, in which case the total mass estimate from inverse models may over or underestimate the mass by 10-20%. The results of the modeling indicate that inversion of time-lapse gravity data is a viable technique for the monitoring of reservoir gas cap waterfloods.
Characterization of a Coalesced, Collapsed Paleocave Reservoir Analog Using GPR and Well-Core Data
(Society of Exploration Geophysicists, 2002-07) McMechan, George A.; Loucks, R. G.; Mescher, P.; Zeng, Xiaoxian; McMechan, George A.; Zeng, Xiaoxian
The three-dimensional architecture, spatial complexity, and pore-type distribution are mapped in a near-surface analog of a coalesced, collapsed paleocave system in the Lower Ordovician Ellenburger Group near the city of Marble Falls in central Texas. The surface area of the site has dimensions of about 350 × 1000 m. The data collected include about 12 km of 50-MHz ground-penetrating radar (GPR) data arranged in a grid of orthogonal lines, 29 cores of about 15-m length, and detailed facies maps of an adjacent quarry face. Electrical property measurements along with detailed core descriptions were the basis of integrated interpretation of the GPR data. Three main GPR facies are defined on the basis of degree of brecciation in the corresponding cores: undisturbed host rock, disturbed host rock, and paleocave breccia. This GPR facies division defined the major paleocave trends and the distribution of porosity types, which correlate with reservoir quality. Highly brecciated zones are separated by disturbed and undisturbed host rock. The breccia bodies that outline the trend of collapsed cave passages are up to 300 m wide: the intervening intact areas between breccias are up to 200 m wide. Understanding the breccia distribution in a reservoir analog will help in defining strategies for efficient development of coalesced, collapsed paleocave reservoirs.
Photograph
(2009-02-18T21:13:06Z) Fraser, Barry J.
Comparison of methods for modeling phase variation with angle
(2011-09) Zhu, Xinfa; McMechan, George
In another paper (Zhu and McMechan, 2011, hereinafter paper I), we show that least squares phase variation with angle (PVA) is capable of being reliably inverted for elastic parameters. A requirement for convergence to the correct solutions is consistency of the forward modeling methods for the synthetic observed data, and the predicted data. This indicates we have to look for a modeling method which can handle realistic geologic structures and produce synthetic (predicted) PVA as close as possible to the field (observed) PVA. This paper is a first step toward this goal. Three methods of measuring phase of a local wavelet are proposed and tested. Three kinds of methods for PVA modeling are discussed, including reflected spherical wave (RSW), reflectivity, and high-order finite difference (FD). Full-wave methods (reflectivity and FD) are preferred over the RSW. For laterally inhomogeneous structures, the differential solution (FD) is preferred over the integral solutions (RSW and reflecivity).
Self-Calibration Technique for Three-Point Intrinsic Alignment Correlations in Weak Lensing Surveys
(2011-11-15) Troxel, Michael A.; Ishak-Boushaki, Mustapha; 0000 0001 2874 3832 (Ishak-Boushaki, M); Troxel, Michael A.; Ishak-Boushaki, Mustapha
The intrinsic alignment (IA) of galaxies has been shown to be a significant barrier to precision cosmic shear measurements. Recently, Zhang proposed a self-calibration technique for the power spectrum to calculate the induced gravitational shear-galaxy intrinsic ellipticity correlation (GI) in weak lensing surveys with photo-z measurements, which is expected to reduce the IA contamination by at least a factor of 10 for currently proposed surveys. We confirm this using an independent analysis and propose an expansion to the self-calibration technique for the bispectrum in order to calculate the dominant IA gravitational shear-gravitational shear-intrinsic ellipticity correlation (GGI) contamination. We first establish an estimator to extract the galaxy density-density-intrinsic ellipticity (ggI) correlation from the galaxy ellipticity-density-density measurement for a photo-z galaxy sample. We then develop a relation between the GGI and ggI bispectra, which allows for the estimation and removal of the GGI correlation from the cosmic shear signal. We explore the performance of these two methods, compare to other possible sources of error, and show that the GGI self-calibration technique can potentially reduce the IA contamination by up to a factor of 5-10 for all but a few bin choices, thus reducing the contamination to the per cent level. The self-calibration is less accurate for adjacent bins, but still allows for a factor of 3 reduction in the IA contamination. The self-calibration thus promises to be an efficient technique to isolate both the two-point and three-point intrinsic alignment signals from weak lensing measurements. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.
Grignard Metathesis (GRIM) Polymerization for the Synthesis of Conjugated Block Copolymers Containing Regioregular Poly(3-Hexylthiophene)
(2011-11-28) Stefan, Mihaela C.; Bhatt, Mahesh P.; Sista, P.; Magurudeniya, H. D.; Stern, Robert J.
The synthesis of various conjugated block copolymers of regioregular poly(3-hexylthiophene) by Grignard metathesis (GRIM) polymerization is described. © 2012 The Royal Society of Chemistry
Preparation and Characterization of Hybrid Conducting Polymer–Carbon Nanotube Yarn
(2011-12-16) Foroughi, Javad; Spinks, Geoffrey M.; Ghorbani, Shaban R.; Kozlov, Mikhail E.; Safaei, Farzad; Peleckis, Germanas; Wallace, Gordon G.; Baughman, Ray H.; 0000 0003 5232 4253 (Baughman, RH)
Hybrid polypyrrole (PPy)-multi walled carbon nanotube(MWNT) yarns were obtained by chemical and electrochemical polymerization of pyrrole on the surface and within the porous interior of twisted MWNT yarns. The material was characterized by scanning electron microscopy, electrochemical, mechanical and electrical measurements. It was found that the hybrid PPy-MWNT yarns possessed significantly higher mechanical strength (over 740 MPa) and Young's modulus (over 54 GPa) than the pristine MWNT yarn. The hybrid yarns also exhibited substantially higher electrical conductivity (over 235 S cm(-1)) and their specific capacitance was found to be in excess of 60 F g(-1). Measurements of temperature dependence of electrical conductivity revealed semiconducting behaviour, with a large increase of band gap near 100 K. The collected low temperature data are in good agreement with a three-dimensional variable range hopping model (3D-VRH). The improved durability of the yarns is important for electrical applications. The composite yarns can be produced in commercial quantities and used for applications where the electrical conductivity and good mechanical properties are of primary importance.
An Assay of DNA by Resonance Light Scattering Technique and its Application in Screening Anticancer Drugs
(2011-12-22) Chen, Xi.; Liu, G.; Liang, S.; Qian, S.; Liu, Jinbin; Chen, Z.
In this contribution, a novel assay has been developed to detect the interaction between DNA and drugs using ethidium bromide (EB) as a probe based on the decreased resonance light scattering (RLS) technique. It was found that, in pH 2.0 Britton-Robinson buffer solution, EB underwent dramatic enhancement of RLS signal when binding to DNA. Additionally, the strong RLS signal of the EB-DNA system was remarkably decreased after the addition of DNA-targeted anticancer drugs. The results showed a linear relationship between the enhanced RLS intensity of the EB-DNA system and concentration of DNA in the range of 0.015-40.8 μg mL -1. The linear regression equation is represented as follows: ΔI RLS = 4.15 + 21.14c with regression coefficient r = 0.9970 (n = 10). The detection limit was 0.3 ng mL -1. Only 2.0 × 10 -8 mol L -1 was selected as the optimum EB concentration in this assay. Further study demonstrated that the anticancer efficacy of anticancer drugs varied inversely with RLS intensity of the EB-DNA-drug system. So, it is intuitive to see the sequence of antitumor efficiency of anticancer drugs without data processing by RLS screening spectra. Compared with the traditional cell-based screening methods, the proposed method was more convenient, rapid and intuitive. The reaction mechanism is discussed. © 2012 The Royal Society of Chemistry.
Spin Textures In Strongly Coupled Electron Spin And Magnetic Or Nuclear Spin Systems In Quantum Dots
(2012) Abolfath, Ramin M.; Korkusinski, M.; Brabec, T.; Hawrylak, P.
Controlling electron spins strongly coupled to magnetic and nuclear spins in solid state systems is an important challenge in the field of spintronics and quantum computation. We show here that electron droplets with no net spin in semiconductor quantum dots strongly coupled with magnetic ion or nuclear spin systems break down at low temperature and form a nontrivial antiferromagnetic spatially ordered spin texture of magnetopolarons. The spatially ordered combined electron-magnetic ion spin texture, associated with spontaneous symmetry breaking in the parity of electronic charge and spin densities and magnetization of magnetic ions, emerges from an ab initio density functional approach to the electronic system coupled with mean-field approximation for the magnetic or nuclear spin system. The predicted phase diagram determines the critical temperature as a function of coupling strength and identifies possible phases of the strongly coupled spin system. The prediction may arrest fluctuations in the spin system and open the way to control, manipulate, and prepare magnetic and nuclear spin ensembles in semiconductor nanostructures.
Measurement of the Semileptonic Branching Fraction of the B_s Meson
(American Physical Society, 2012-01-03) Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D. A.; Izen, Joseph M.; Lou, Xinchou; 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We report a measurement of the inclusive semileptonic branching fraction of the B_s meson using data collected with the BABAR detector in the center-of-mass energy region above the Υ(4S) resonance. We use the inclusive yield of mesons and the yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of B_s mesons relative to all B mesons as a function of center-of-mass energy. The inclusive semileptonic branching fraction of the B_s meson is determined to be ℬ(B_s → ℓνX) = 9.5_{-2.0}^{+2.5}(stat)_{-1.9}^{+1.1}(syst)%, where ℓ indicates the average of e and μ.
Stabilization in a State-Dependent Model of Turning Processes
(SIAM, 2012-01-03) Hu, Qingwen; Krawcewicz, Wieslaw; Turi, Jànos; 0000 0001 1616 0605 (Krawcewicz, W); 0000 0000 4128 774X (Turi, J); 89645792 (Krawcewicz, W); 88656618 (Turi, J); Hu, Qingwen; Krawcewicz, Wieslaw; Turi, Jànos
We consider a two-degree-of-freedom model for turning processes which involves a system of differential equations with state-dependent delay. Depending on process parameters (e.g., spindle speed, depth of cut) the cutting tool can exhibit unwanted vibrations, resulting in a nonsmooth surface of the workpiece. In this paper we propose a feedback law to stabilize the turning process for a large range of system parameters. The feedback law introduces a generic nonhyperbolic stationary point into the model, which generates the main technical challenge of this work. We establish the stability equivalence between the differential equations with state-dependent delay and a corresponding nonlinear system with the delay fixed at its stationary value. Then we show the stability of that nonlinear system with constant delay by computing its normal form. Finally, we obtain conditions on system parameters which guarantee the stability of the state-dependent delay model at the nonhyperbolic stationary point. ©2012 Society for Industrial and Applied Mathematics.
A Highly Efficient and Effective Motif Discovery Method for ChIP-Seq/ChIP-Chip Data using Positional Information
(2012-01-06) Ma, Xiaotu; Kulkarni, Ashwinikumar; Zhang, Zhihua; Xuan, Zhenyu; Serfling, Robert J. (Robert Joseph); Zhang, Michael Q.; 0000 0001 1707 1372 (Zhang, MQ); 99086074‏ ‎(Zhang, MQ); Zhang, Michael Q.
Identification of DNA motifs from ChIP-seq/ChIP-chip [chromatin immunoprecipitation (ChIP)] data is a powerful method for understanding the transcriptional regulatory network. However, most established methods are designed for small sample sizes and are inefficient for ChIP data. Here we propose a new k-mer occurrence model to reflect the fact that functional DNA k-mers often cluster around ChIP peak summits. With this model, we introduced a new measure to discover functional k-mers. Using simulation, we demonstrated that our method is more robust against noises in ChIP data than available methods. A novel word clustering method is also implemented to group similar k-mers into position weight matrices (PWMs). Our method was applied to a diverse set of ChIP experiments to demonstrate its high sensitivity and specificity. Importantly, our method is much faster than several other methods for large sample sizes. Thus, we have developed an efficient and effective motif discovery method for ChIP experiments.
Search for B̄→Λ_c⁺Xℓ⁻ν̅_ℓ decays in Events with a Fully Reconstructed B Meson
(American Physical Society, 2012-01-12) Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D. A.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We present a search for semileptonic B decays to the charmed baryon Λc+ based on 420fb -1 of data collected at the Υ(4S) resonance with the BABAR detector at the PEP-II e +e - storage rings. By fully reconstructing the recoiling B in a hadronic decay mode, we reduce non-B backgrounds and determine the flavor of the signal B. We statistically correct the flavor for the effect of the B0 mixing. We obtain a 90% confidence level upper limit of B(B̄→Λc+X -ν ̄)/B(B̄→Λc+X)<3.5%. © 2012 American Physical Society.
Coherent Emission from a Disordered Organic Semiconductor Induced by Strong Coupling with Surface Plasmons
(American Physical Society, 2012-02) Guebrou, S. Aberra; Symonds, C.; Homeyer, E.; Plenet, J. C.; Gartstein, Yuri N.; Agranovich, Vladimir M.; Bellessa, J.; 0000 0001 0919 7733 (Agranovich, VM); 82001615 (Agranovich, VM)
In this Letter, we show that the strong coupling between a disordered set of molecular emitters and surface plasmons leads to the formation of spatially coherent hybrid states extended on macroscopic distances. Young-type interferometric experiments performed on a system of J-aggregated dyes spread on a silver layer evidence the coherent emission from different molecular emitters separated by several microns. The coherence is absent in systems in the weak-coupling regime demonstrating the key role of the hybridization of the molecules with the plasmon.
Shock Fronts, Electron-Ion Equilibration and Intracluster Medium Transport Processes in the Merging Cluster Abell 2146
(2012-02) Russell, H. R.; Mcnamara, B. R.; Sanders, J. S.; Fabian, A. C.; Nulsen, P. E. J.; Canning, R. E. A.; Baum, S. A.; Donahue, M.; Edge, A. C.; King, Lindsay J.; O'Dea, C. P.; 0000 0001 2437 3571 (King, LJ); King, Lindsay J.
We present a new 400-ks Chandra X-ray observation of the merging galaxy cluster Abell 2146. This deep observation reveals detailed structure associated with the major merger event including theMach numberM =2.3±0.2 bowshock ahead of the dense, ram pressure stripped subcluster core and the first known example of an upstream shock in the intracluster medium (ICM) (M = 1.6 ± 0.1). By measuring the electron temperature profile behind each shock front, we determine the time-scale for the electron population to thermally equilibrate with the shock-heated ions.We find that the temperature profile behind the bow shock is consistent with the time-scale for Coulomb collisional equilibration and the post-shock temperature is lower than expected for instant shock heating of the electrons. Although like the Bullet cluster the electron temperatures behind the upstream shock front are hotter than expected, favouring the instant heating model, the uncertainty on the temperature values is greater here and there is significant substructure complicating the interpretation. We also measured the width of each shock front and the contact discontinuity on the leading edge of the subcluster core to investigate the suppression of transport processes in the ICM. The upstream shock is ∼440 kpc in length but appears remarkably narrow over this distance with a best-fitting width of only 6+5 −3 kpc compared with the mean free path of 23 ± 5 kpc. The leading edge of the subcluster core is also narrow with an upper limit on the width of only 2 kpc separating the cool, multiphase gas at 0.5–2 keV from the shock-heated surrounding ICM at ∼6 keV. The strong suppression of diffusion and conduction across this edge suggests a magnetic draping layer may have formed arou0nd the subcluster core. The deep Chandra observation has also revealed a cool, dense plume of material extending ∼170 kpc perpendicular to the merger axis, which is likely to be the disrupted remnant of the primary cluster core. This asymmetry in the cluster morphology indicates the merger has a non-zero impact parameter. We suggest that this also explains why the south-western edge of the subcluster core is narrow and stable over ∼150 kpc in length, but the north-eastern edge is broad and being stripped of material.
Sensitivity of Estimated Elastic Moduli to Completeness of Wave Type, Measurement Type, and Illumination Apertures at a Receiver in Multicomponent VSP Data
(2012-02-01) Rusmanugroho, Herurisa; McMechan, George A.; McMechan, George A.
Inversion of phase slowness and polarization vectors measured from multicomponent vertical seismic profile data can yield estimates of all 21 density-normalized elastic moduli for anisotropic elastic media in the neighborhood of each 3C geophone. Synthetic test data are produced by direct evaluation of the Christoffel equation, and by finite-difference solution of the elastodynamic equations. Incompleteness of the data, with respect to illumination (polar and azimuth angle) apertures (qP and/or qS) wave types, wave-propagation directions, and the amount of data (e.g., with or without horizontal slowness components), produces solutions with variations in quality, as revealed by the distribution of model parameter correlations. In a good solution, with all parameters well constrained by the data, the correlation matrix is diagonally dominant. qP-only and qS-only solutions typically produce complementary distributions in their correlation matrices, as they are orthogonal in their sampling of the medium with respect to polarization. The elastic moduli become less independent as the data apertures decrease. If the other input data are relatively complete, the horizontal components of the slowness vector are not needed as the information they contain is redundant. The main consequence of omitting horizontal slowness components is slower convergence. When modest amounts of random noise are added to the slowness and polarization data, in otherwise adequately sampled apertures, the solution is still very close to the correct model, but with larger residual variance. © 2012 Society of Exploration Geophysicists.
Search for CP Violation in the Decay τ⁻ → π⁻ K_S⁰(0π⁰)ν_τ
(American Physical Society, 2012-02-13) Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D. A.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We report a search for CP violation in the decay τ⁻ → π⁻ K_S⁰ (0π⁰)ν_τ using a data set of 437×106 τ-lepton pairs, corresponding to an integrated luminosity of 476 fb⁻¹, collected with the BABAR detector at the PEP-II asymmetric-energy e⁺e⁻ storage rings. The CP-violating decay-rate asymmetry is determined to be (-0.36 ± 0.23 ± 0.11)% approximately 2.8 standard deviations from the standard model prediction of (0.36 ± 0.01)%.
Refractive Convergent Plasma Lenses Explain Extreme Scattering Events and Pulsar Scintillation
(2012-02-27) Pen, Ue-Li; King, Lindsay J.; 0000 0001 2437 3571 (King, L); King, Lindsay J.
We propose convergent plasma lenses, possibly from current sheets, as a generic solution to strong interstellar scattering. These lenses resolve the overpressure problem by geometric alignment as noted by Goldreich & Shridhar. Our new model further quantitatively explains properties of extreme scattering events and pulsar parabolic arcs. It makes quantitative predictions testable by VLBI on scattering events. It differs conceptually from previous models by occurring through rare, localized underdense sheets. Such sheets are thermally and kinematically stable, and could be consequences of reconnection. The apparent diffractive effects are a result of coherent interference of refractive images. We propose that these lenses can be used for precision distance determination to pulsars, enabling accurate gravity source localization.

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