198,917 research outputs found
Crooks
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/427935Surname: Crooks. Given Name(s) or Initials: . Military Service Number or Last Known Location: [No Service Number]. Prisoner of War Enquiry Card Index Number: M/764. Division Enquiry: [No Division recorded]. Rank: Warrant Officer. Unit: Malaya326692
Item: [2016.0049.60197] "Crooks
Crooks, Stella M.
No full textObituary of Stella Marie Crooks born Aug. 26, 1906 in Canada. Resided in Newport, Michigan
Preliminary studies of the influence of forces and kinetics on interfacial colloidal assembly
No full textIn this research we illustrate how particle-particle and particle-substrate interactions affect structure in interfacial colloidal systems. A number of tools are used to quantify characteristics of deposited structures. These results help understand the effects of colloidal system interactions and deposition kinetics on the degree of ordering in interfacial colloidal structures.
The first set of experiments involve 2.34 ?m silica colloids interacting with silica substrates in 0mM, 5mM, 10mM, and 100mM NaCl solutions. Only the 100mM NaCl solution resulted in rapid deposition driven by van der Waals attraction, while residual electrostatic repulsion produced levitation at lower ionic strengths. This allowed direct observation of the effects of varying magnitudes of attractive interactions on interfacial colloidal structures. Rapid deposition of positively charged 1?m latex colloids on negatively charged silica substrates driven by Coulombic and van der Waals attraction produced surface structures similar to those obtained with only van der Waals attraction. Experiments on 2.34 ?m silica colloids interacting with silica substrates in 10mM NaCl/pH 5.5 and 10mM NaCl/pH 10 conditions resulted in slower deposition rates. It was also found that slower deposition rates produced more compact structures displaying a higher degree of order.
Another set of experiments was aimed at understanding interactions and structures formed in systems of polymerically levitated particles. Total internal reflection microscopy (TIRM) experiments revealed the influence of underlying substrate chemistry on interaction profiles in these systems. Basic experiments were also performed on the effects of varying amounts of specific ions on the dispersion stability in these systems. At conditions producing instability in polymeric systems, a similar degree of order was observed in comparison to experiments involving rapid deposition via salt addition in electrostatically stabilized systems.
The results of this research clearly indicate that particle-particle and particle-substrate interactions are critical in determining structure formation by deposition. While the principal focus of this research is to study structures formed in various kinetic regimes, it also provides a basis for future studies aimed at tuning attractive interactions to produce equilibrium colloidal crystals on substrates
The synthesis and characterisation of complex metal oxide materials
No full textA new palladate analogue, Ba11Pd11O20(CO3)2, of the complex copper oxide carbonate, Ba44Cu48O87.9(CO3)6, has been synthesised by reaction of PdO and BaCO3 at 810oC. The structure of this phase and that of the isostructural nickelate have been refined from high resolution powder neutron diffraction data. The structure consists of M18O24 cages and M6O12 rings (M = Pd, Ni), previously unknown for these metals, separated by barium ions and carbonate groups. A section of the structure separating two of M18O24 units exhibits a high degree of disorder and has been refined as containing either carbonate groups or isolated MO4 square planes. The presence and symmetry of the carbonate groups in these structures has been investigated by infrared and Raman spectroscopy.Three solid solutions containing copper and palladium in square planar coordination have been synthesised and characterised. The 'BaCuxPd1-xO2' system adopts the barium palladium oxide carbonate structure, described above, over the entire range of x(0 ≤ x ≤ 1). CuxPd2-x O2 (0 ≤ x ≤ 11/2) has also been studied, crystallising with the PdO structure type, although the purely copper containing material, CuO, could not be synthesised with this structure. Sr2CuxPd1-xO3 (0 < x < 1) was found to be isostructural with the end members of the series. Attempts to introduce palladium into the double chains of copper oxygen square planes in YBa2Cu4O8+δ were unsuccessful.Complete structural characterisation of Pb2Ba2Cu2MO8Cl (M = Nb, Ta) via the combined refinement of powder x-ray and neutron diffraction data, has been achieved, confirming the previous x-ray refinement. Structural analogues of this material have been synthesised giving the series of compounds, PbyBa4-yCu2MO8X (y = 2, 3; M = Nb, Ta, Sb; X = Cl, Br) of which seven new products have been isolated. Structural characterisation of these materials has been performed using the Rietveld refinement of powder x-ray diffraction data, indicating that all of these materials adopt the PB2Ba2Cu2TaO8Cl structure type where Pb2Cl layers separate triple layers formed from two CuO5 square pyramids sandwiching a distorted TaO6 octahedron.</p
Front speeds in the vanishing diffusion limit for reaction-diffusion-convection equations
No full textTravelling fronts for scalar balance laws with monostable
reaction, possibly non-convex flux, and viscosity ε ≥ 0 exist for all velocities greater than or equal to an ε-dependent minimal value, both in the parabolic case when ε > 0 and in the hyperbolic case when ε = 0. We prove that as ε → 0, the minimal velocity c∗ε converges to c∗, the minimal value when ε = 0, and that c∗ε ≥ c∗ for all ε > 0. The proof uses comparison theorems and the variational characterization of the minimal parabolic front velocity. This convergence also yields a reaction-independent sufficient condition for the minimal velocity of the parabolic problem for small positive ε to be strictly greater than the value predicted by the problem linearized about the unstable equilibrium, that is, for the minimal-velocity travelling front of the viscous equation to be pushed for sufficiently small ε
Crooks Relation in Optical Spectra: Universality in Work Distributions for Weak Local Quenches
No full textWe show that work distributions and nonequilibrium work fluctuation theorems can be measured in optical spectra for a wide class of quantum systems. We consider systems where the absorption or emission of a photon corresponds to the sudden switch on or off of a local perturbation. For the particular case of a weak local perturbation, the Crooks relation establishes a universal relation in absorption as well as in emission spectra. Because of a direct relation between the spectra and work distribution functions this is equivalent to universal relations in work distributions for weak local quenches. As two concrete examples we treat the x-ray edge problem and the Kondo exciton
Land Cover in a Managed Forest Ecosystem: Mexican Shade Coffee
No full textManaged forest ecosystems—agroforestry systems in which crops such as coffee and bananas are planted side-by-side with woody perennials—are being touted as a means of safeguarding forests along with the ecological services they provide. Yet we know little about the determinants of land cover in such systems, information needed to design effective forest conservation policies. This paper presents a spatial regression analysis of land cover in a managed forest ecosystem—a shade coffee region of coastal Mexico. Using high-resolution land cover data derived from aerial photographs along with data on the geophysical and institutional characteristics of the study area, we find that plots in close proximity to urban centers are less likely to be cleared, all other things equal. This result contrasts sharply with the literature on natural forests. In addition, we find that membership in coffee-marketing cooperatives, farm size, and certain soil types are associated with forest cover, while proximity to small town centers is associated with forest clearing.deforestation, managed forest ecosystem, agroforestry, shade-grown coffee, Mexico, spatial econometrics, land cover
Method and apparatus for nanoparticle transport and detection
No full textAccording to one embodiment an apparatus includes a membrane and at least a portion of a nanotube imbedded within the membrane. The portion of the nanotube imbedded within the membrane provides a conduit through the membrane.U
The introduction of palladium into superconducting cuprate materials
No full textA series of doped parent compounds of the form Sr2CuχM1-χO3 (M=Pd, Ni) have been prepared, and successfully fluorinated, forming Sr2CuχM1-χO2F 2+δ. Rietveld refinement of powder x-ray diffraction data indicates expanding cell parameters with dopant level, as expected with the introduction of a larger cation. Investigation into the YBa2Cu4O8 system has shown very little palladium doping can be achieved.</p
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
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