UScholar Works
 
Filters: Collection: "ir_uspace"
51 - 75 of 967
Number of results to display per page
CreatorTitleDescriptionSubjectDate
51 Voth, Gregory AlanElectronic structure calculation of the structures and energies of the three pure polymorphic forms of crystalline HMXThe molecular structures and energetic stabilities of the three pure polymorphic forms of crystalline HMX were calculated using a first-principles electronic-structure method. The computations were performed using the local density approximation in conjunction with localized "fireball" orbitals and ...HMX; Crystalline HMX; Molecular geometry2000
52 Gerig, GuidoParticle based shape regression of open surfaces with applications to developmental neuroimagingShape regression promises to be an important tool to study the relationship between anatomy and underlying clinical or biological parameters, such as age. In this paper we propose a new method to building shape models that incorporates regression analysis in the process of optimizing correspondences...2009-01-01
53 Gerig, GuidoQuantification of measurement error in DTI: theoretical predictions and validationThe presence of Rician noise in magnetic resonance imaging (MRI) introduces systematic errors in diffusion tensor imaging (DTI) measurements. This paper evaluates gradient direction schemes and tensor estimation routines to determine how to achieve the maximum accuracy and precision of tensor derive...2007-01-01
54 Wight, Charles AlbertThermal dissociation kinetics of solid and liquid ammonium nitrateThermogravimetry has been used to study the kinetics of the thermal dissociation of solid and liquid ammonium nitrate. Model-fitting and model-free kinetic methods have been applied to the sets of isothermal and nonisothermal measurements to derive kinetic characteristics of the processes. The appli...Thermal dissociation kinetics2001
55 Gerig, GuidoUnbiased atlas formation via large deformations metric mappingThe construction of population atlases is a key issue in medical image analysis, and particularly in brain mapping. Large sets of images are mapped into a common coordinate system to study intrapopulation variability and inter-population differences, to provide voxelwise mapping of functional sites,...Computational anatomy; Brain atlases; Image metric space2005-01-01
56 Hawkes, KristenAffluent hunters? Some comments in light of the Alyawara caseOur recent analysis (O'Connell and Hawkes in press) of plant food collecting among the Alyawara, a central Australian hunting group, shows that the cost of subsistence is sometimes quite high, far higher than the current conven. tional wisdom regarding hunters would suggest. We infer from available ...1981-01-01
57 Gerig, GuidoBrain lesion segmentation through physical model estimationSegmentations of brain lesions from Magnetic Resonance (MR) images is crucial for quantitative analysis of lesion populations in neuroimaging of neurological disorders. We propose a new method for segmenting lesions in brain MRI by inferring the underlying physical models for pathology. We use the r...Magnetic resonance (MR) images; Neurological disorders; Diffusion tensor imaging (DTI).2008-01-01
58 Wight, Charles AlbertCompetitive vaporization and decomposition of liquid RDXThe thermal decomposition of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Activation energies as a function of the extent of conversion, ?, have been determined by model-free isoconversional analysis o...Liquid RDX; Competitive vaporization; Thermal decomposition; Differential scanning calorimetry2000
59 Hawkes, KristenEvaluating grandmother effectsWomen who have outlived child-bearing have long been described as post-reproductive. But contributions they make to the survival or fertility of their descendants enhance the reproduction of their genes. Consequently natural selection affects this characteristic stage of human life history. Grandmot...Human life history; Historical demography; Human longevity2009-01-01
60 Sorensen, Justin BruceGeoreferenced Logan, 1930: sheet 35 (.kmz file)This .kmz file contains a georeferenced sheet overlay from the Sanborn Fire Insurance Maps for Logan, 1930. The downloaded .kmz file is accessible for viewing in Google Earth and other GIS software systems. Multiple .kmz files can be loaded into a GIS software system in order to view a continuous s...data modeling; GIS; ArcGIS; Google Earth; historic GIS2013
61 Sorensen, Justin BruceGeoreferenced Ogden, 1950: sheet 12 (.kmz file)This .kmz file contains a georeferenced sheet overlay from the Sanborn Fire Insurance Maps for Ogden, 1950. The downloaded .kmz file is accessible for viewing in Google Earth and other GIS software systems. Multiple .kmz files can be loaded into a GIS software system in order to view a continuous se...data modeling; GIS; ArcGIS; Google Earth; historic GIS2013
62 Pugmire, Ronald J.Investigation of the structural conformation of biphenyl by solid state 13C NMR and quantum chemical NMR shift calculationsThe principal values of the 13C chemical-shift tensor (CST) for biphenyl have been determined with the FIREMAT experiment. The internal dihedral angle between the benzene rings in biphenyl is estimated to fall between 10 and 20° on the basis of quantum mechanical calculations of the CST principal v...Carbon-13; Chemical-shift tensor; biphenyl; FIREMAT2001
63 Eddings, Eric G.; Sarofim, Adel F.Journey from n-heptane to liquid transportation fuels. 1. The role of the allylic radicals and its related species in aromatic precursor chemistryThe Utah normal heptane mechanism compiled from submechanisms in the literature was extended into a detailed normal decane combustion mechanism, which is a subset of the Utah surrogate mechanisms. Few species have greater impact on the concentrations of other species than the allyl radical CH2CHCH2....Utah Surrogate Mechanisms; Heptane mechanism; Decane combustion mechanism; Allyl radical; Aromatic precursors2008
64 Wight, Charles AlbertKinetic study of stabilizing effect of oxygen on thermal degradation of poly(methyl methacrylate)The thermal degradation of poly(methyl methacrylate) (PMMA) has been studied in both pure nitrogen and oxygen-containing atmospheres. The presence of oxygen increases the initial decomposition temperature by 70 °C. The stabilizing effect of oxygen may be explained by forming thermally stable radica...Poly(methyl methacrylate); PMMA; Thermal degradation; Isoconversional method1999
65 Page 2
66 Borodin, Oleg; Smith, Grant D.; Bedrov, DmitroPolarizable and nonpolarizable force fields for alkyl nitratesQuantum-chemistry-based many-body polarizable and two-body nonpolarizable atomic force fields were developed for alkyl nitrate liquids and pentaerythritol tetranitrate (PETN) crystal. Bonding, bending, and torsional parameters, partial charges, and atomic polarizabilities for the polarizable force f...Alkyl nitrate; Pentaerythritol tetranitrate; PETN; Polarizable atomic force fields; Nonpolarizable atomic force fields2007
67 Gerig, GuidoProbabilistic fiber tracking using particle filteringThis paper presents a novel and fast probabilistic method for white matter fiber tracking from diffusion weighted MRI (DWI). We formulate fiber tracking on a nonlinear state space model which is able to capture both smoothness regularity of fibers and uncertainties of the local fiber orientations du...2007-01-01
68 Wu, Yong-ShiRenormalization of the statistics parameter in three-dimensional electrodynamicsWe argue that the p function for the statistics parameter in (2+1)-dimensional electrodynamics is zero to all orders in perturbation theory beyond one loop. We show that there can be finite radiative corrections from massless charged scalar fields.Renormalization1989-02
69 Mattis, Daniel C.Phase transition of model interacting chainsThe partition function of n interacting chains having a phase transition at Tc(n) is reduced, by the transfer-matrix formalism, to the determination of an w-body bound state in one dimension. Subject to mild restrictions on the potentials, this w-body problem can be analyzed in terms of a two-body p...Phase transition; Interacting chains1981-12
70 Voth, Gregory AlanAb initio calculations of reactive pathways for ?-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (?-HMX)Using the BLYP and B3LYP level of density functional theory, four possible decomposition reaction pathways of HMX in the gas phase were investigated: N?NO2 bond dissociation, HONO elimination, C?N bond scission of the ring, and the concerted ring fission. The energetics of each of these four mechan...Ab initio calculations; Reactive pathways; HMX2000
71 Hawkes, KristenAge-related decline in ovarian follicle stocks differ between chimpanzee (Pan troglodytes) and humansSimilarity in oldest parturitions in humans and great apes suggests that we maintain ancestral rates of ovarian aging. Consistent with that hypothesis, previous counts of primordial follicles in postmortem ovarian sections from chimpanzees (Pan troglodytes) showed follicle stock decline at the same ...2015-01-01
72 Truong, ThanhBranching ratio and pressure dependent rate constants of multichannel unimolecular decomposition of gas-phase ?-HMX: an ab initio dynamics studyThe dynamics of the initial thermal decomposition step of gas-phase ?-HMX is investigated using the master equation method. Both the NO2 fission and HONO elimination channels were considered. The structures, energies, and Hessian information along the minimum energy paths (MEP) of these two channels...Thermal decomposition; HMX2001
73 Truong, ThanhDirect ab initio dynamics studies of the hydrogen abstraction reactions of hydrogen atom with fluoromethanesA direct ab initio dynamics study on the gas-phase reactions of atomic hydrogen with different fluoromethanes has been carried out. The thermal rate constants were calculated using canonical variational transition state (CVT) theory augmented by multidimensional semiclassical zero and small curvatur...Hydrogen abstraction reactions; Gas-phase reactions; Fluoromethanes; Thermal rate constants; Moller?Plesset perturbation theory; Hybrid density functional theory1999
74 Gerig, GuidoEvaluation of brain MRI alignment with the Robust Hausdorff Distance MeasuresWe present a novel automated method for assessment of image alignment, applied to non-rigid registration of brain Magnetic Resonance Imaging data (MRI) for image-guided neurosurgery. We propose a number of robust modifications to the Hausdorff distance (HD) metric, and apply it to the edges recovere...Magnetic resonance imaging (MRI)2008-01-01
75 Gerig, GuidoFiber tract-oriented statistics for quantitative diffusion tensor MRI analysisDiffusion tensor imaging (DTI) has become the major modality to study properties of white matter and the geometry of fiber tracts of the human brain. Clinical studies mostly focus on regional statistics of fractional anisotropy (FA) and mean diffusivity (MD) derived from tensors. Existing analysis t...Diffusion tensor interpolation, Diffusion tensor statistics, DTI analysis, Fiber tract modeling2006-01-01
51 - 75 of 967