Scale-up of electrospray atomization using linear arrays of Taylor cones

Linear arrays of Taylor cones were established on capillary electrode tubes opposite a slotted flat plate counterelectrode to investigate the feasibility of increasing the liquid throughput rate in electrospray atomizers. It was found that individual Taylor cones could be established on each capillary over a wide range of the capillary radius to spacing ratio R/S. The onset potential Vs required to establish the cones varied directly with R/S, but the liquid flow rate per cone and current per cone were nearly independent of R/S for a given overpotential ratio P=V/Vs. Only six working capillaries were used, but the results per cone are applicable to larger arrays of cones since end effects were minimized

A noncontact measurement technique for the specific heat and total hemispherical emissivity of undercooled refractory materials

A noncontact measurement technique for the constant pressure specific heat (c(pl)) and the total hemispherical emissivity (epsilon(T1)) of undercooled refractory materials is presented. In purely radiative cooling, a simple formula which relates the post-recalescence isotherm duration and the undercooling level to c(pl) is derived. This technique also allows us to measure epsilon(Tl) once C(pl) is known. The experiments were performed using the high-temperature high-vacuum electrostatic levitator at JPL in which 2-3 mm diameter metallic samples can be levitated, melted, and radiatively cooled in vacuum. The averaged specific heats and total hemispherical emissivities of Zr and Ni over the undercooled regions agree well with the results obtained by drop calorimetry: C(pl,av(Zr)=40.8+/-0.9 J/mol K, epsilon(Tl,av) (Zr)=0.28+/-0.01, c(pl,av)(Ni)=42.6+/-0.8 J/mol K, and epsilon(Tl,av)(Ni)=0.16+/-0.01

DEFINING THE ENDMEMBER SYSTEM OF US SOILS AND QUANTIFYING RELATIONSHIPS, AND A HYPERSPECTRAL APPROACH TO THE ALTERATION STRENGTH INDEX

Soils form a complex part of the environment, providing important functions in systems such as food production, groundwater movement, and ecosystem health. There have been numerous studies on soil geochemistry and the origin of elements within soils, but few studies into quantifying the relationships between elements and geographical data on a national scale. Using geochemical data obtained by the USGS, the surficial soils of the US were defined by a 13-endmember system using Polytopic Vector Analysis and mapped in GIS. Correlation matrices provided Pearson’s correlation coefficients for elements in the Top 5 cm soil profile, the A horizon, and the C horizon. The Top 5 cm element concentrations were also correlated with the endmembers, and geographical data for land cover, soil order, and soil pH. The quantification of these relationships supported many of the spatial patterns shown in maps and provided insight into other relationships, especially where correlation is weaker. The high spectral resolution of hyperspectral imagery has provided revolutionary advancements in many fields, including mineral identification. Hyperspectral core data from the company Corescan allowed for quantifiable mineral proportions for core sections from Karaha Telaga-Bodas, in Indonesia, and Lake City Caldera, in Colorado. The Alteration Strength Index (ASI) is a value based on mineral parameters that correlate to rock strength. The incorporation of hyperspectral data in the ASI aimed to improve the accuracy of the mineralogical parameters and provide more reliable strength data which in turn would reduce the need for time-consuming lab testing. Results showed that for the Telaga Bodas and Lake City samples, the ASI was not able to provide rock strength estimates within a reasonable range, and calibration of mineralogical parameters may be needed for samples with low ASI values. Though hyperspectral data may be a valuable tool in this venture, other issues with the current ASI would need to be resolved

Inward electrostatic precipitation of interplanetary particles

An inward precipitator collects particles initially dispersed in a gas throughout either a cylindrical or spherical chamber onto a small central planchet. The instrument is effective for particle diameters greater than about 1 µm. One use is the collection of interplanetary dust particles which are stopped in a noble gas (xenon) by drag and ablation after perforating the wall of a thin-walled spacecraft-mounted chamber. First, the particles are positively charged for several seconds by the corona production of positive xenon ions from inward facing needles placed on the chamber wall. Then an electric field causes the particles to migrate toward the center of the instrument and onto the planchet. The collection time (of the order of hours for a 1 m radius spherical chamber) is greatly reduced by the use of optimally located screens which reapportion the electric field. Some of the electric field lines terminate on the wires of the screens so a fraction of the total number of particles in the chamber is lost. The operation of the instrument is demonstrated by experiments which show the migration of carbon soot particles with radius of approximately 1 µm in a 5-cm-diam cylindrical chamber with a single field enhancing screen toward a 3.2 mm central collection rod

Experimental determination of a time–temperature-transformation diagram of the undercooled Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 alloy using the containerless electrostatic levitation processing technique

High temperature high vacuum electrostatic levitation was used to determine the complete time–temperature–transformation (TTT) diagram of the Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 bulk metallic glass forming alloy in the undercooled liquid state. This is the first report of experimental data on the crystallization kinetics of a metallic system covering the entire temperature range of the undercooled melt down to the glass transition temperature. The measured TTT diagram exhibits the expected "C" shape. Existing models that assume polymorphic crystallization cannot satisfactorily explain the experimentally obtained TTT diagram. This originates from the complex crystallization mechanisms that occur in this bulk glass-forming system, involving large composition fluctuations prior to crystallization as well as phase separation in the undercooled liquid state below 800 K

Metallic glass formation in highly undercooled Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 during containerless electrostatic levitation processing

Various sample sizes of Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 with masses up to 80 mg were undercooled below Tg (the glass transition temperature) while electrostatically levitated. The final solidification product of the sample was determined by x-ray diffraction to have an amorphous phase. Differential scanning calorimetry was used to confirm the absence of crystallinity in the processes sample. The amorphous phase could be formed only after heating the samples above the melting temperature for extended periods of time in order to break down and dissolve oxides or other contaminants which would otherwise initiate heterogeneous nucleation of crystals. Noncontact pyrometry was used to monitor the sample temperature throughout processing. The critical cooling rate required to avoid crystallization during solidification of the Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 alloy fell between 0.9 and 1.2 K/s

Hemispherical total emissivity and specific heat capacity of deeply undercooled Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 melts

High-temperature high-vacuum electrostatic levitation (HTHVESL) and differential scanning calorimetry (DSC) were combined to determine the hemispherical total emissivity epsilon T, and the specific heat capacity cp, of the undercooled liquid and throughout the glass transition of the Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 bulk metallic glass forming alloy. The ratio of cp/epsilon T as a function of undercooling was determining from radiative cooling curves measured in the HTHVESL. Using specific heat capacity data obtained by DSC investigations close to the glass transition and above the melting point, epsilon T and cp were separated and the specific heat capacity of the whole undercooled liquid region was determined. Furthermore, the hemispherical total emissivity of the liquid was found to be about 0.22 at 980 K. On undercooling the liquid, the emissivity decreases to approximately 0.18 at about 670 K, where the undercooled liquid starts to freeze to a glass. No significant changes of the emissivity are observed as the alloy undergoes the glass transition

Study of matter current effects in two-body inelastic collisions

At the present time no comprehensive model of high energy hadronic scattering exists. Most of the existing models have a very restricted range of application. The geometrical model of hadronic scattering proposed by Chou and Yang has had great success in predicting high energy scattering phenomena. For example, the dip in pp elastic scattering, and pion and kaon radii were quite accurately predicted by the model. Use of pp differential cross section data also yields an excellent fit of the measured proton form factor in this model. The possible existence of hadronic matter current inside a polarized hadron and an experimental test of this idea were discussed by Chou and Yang in 1973. Subsequently the geometrical model was generalized to include the matter current effect by the same authors in 1976. The proposed experimental test of the matter current idea consists of determining the spin-rotation parameter, R, in polarized elastic meson-proton scatterings. The measurement of R usually requires a second scattering of the recoil proton off a known analyzer such as /sup 12/C. The purpose of this work is to offer another method by which the hadronic matter current effect can be detected. Instead of elastic scattering the two-body inelastic scattering process ..pi../sup -/ p ..-->.. K/sup 0/..lambda.. in which the final state hyperon is unstable against weak decay is considered. By observing the angular distribution of the decay products the rotation parameter, R, may be inferred

The Full Complexity of Being Human: A Study of Science and Art

Thesis advisor: Scott T. CummingsThis Senior Honors Thesis evolved from a personal fascination with the intersection of art and science both in drama and on a grander theoretical scale. It is a three-part investigation with each part written in different voice with a different intention. The first is a short personal introduction offering insight to the genesis of the project. This is followed by a comparative dramaturgical analysis of two science plays, Bertolt Brecht's GALILEO and Michael Frayn's COPENHAGEN, examining the role of science in drama. The final component is a philosophical dialogue on the model of Brecht's MESSINGKAUF DIALOGUES which articulates larger philosophical questions in an examination of the similarities and differences between science and art.Thesis (BA) — Boston College, 2006.Submitted to: Boston College. College of Arts and Sciences.Discipline: Theater.Discipline: College Honors Program