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Geometric Challenges in Designing Parts for Machining using Wire-fed DED
Wire-fed DED using MIG welding systems allows for high deposition rates
above 30lbs/hr, enabling much larger parts to be printed than would be possible on
other DED systems. However, a drawback to this high deposition rate is a relatively
low bead resolution on the printed part. Post-processing using machining is usually
required on any mating surfaces printed using wire-fed DED. Problems such as
residual stress in the build plate and printed part, underbuilding, and path
interpolations can all lead to insufficient material deposition and deviation from the
desired shape. These areas where the printed part varies from the model can leave
defects on post-processed surfaces. This paper will cover common geometry issues
that can arise from wire-fed DED and design changes that can be made to ensure that
the printed design contains the required material to achieve the finished part.Mechanical Engineerin
Density Changes in Low Pressure Gas Targets for Electron Scattering Experiments
A system of modular sealed gas target cells has been developed for use in
electron scattering experiments at the Thomas Jefferson National Accelerator
Facility (Jefferson Lab). This system was initially developed to complete the
MARATHON experiment which required, among other species, tritium as a target
material. Thus far, the cells have been loaded with the gas species 3H, 3He,
2H, 1H and 40Ar and operated in nominal beam currents of up to 22.5 uA in
Jefferson Lab's Hall A. While the gas density of the cells at the time of
loading is known, the density of each gas varies uniquely when heated by the
electron beam. To extract experimental cross sections using these cells,
density dependence on beam current of each target fluid must be determined. In
this study, data from measurements with several beam currents within the range
of 2.5 to 22.5 uA on each target fluid are presented. Additionally, expressions
for the beam current dependent fluid density of each target are developed.Comment: 8 pages, 12 figures, 4 table
Vanadium(IV) complexes with methyl-substituted 8-hydroxyquinolines : catalytic potential in the oxidation of hydrocarbons and alcohols with peroxides and biological activity
Methyl-substituted 8-hydroxyquinolines (Hquin) were successfully used to synthetize
five-coordinated oxovanadium(IV) complexes: [VO(2,6-(Me)2-quin)2] (1), [VO(2,5-(Me)2-quin)2] (2)
and [VO(2-Me-quin)2] (3). Complexes 1â3 demonstrated high catalytic activity in the oxidation of
hydrocarbons with H2O2 in acetonitrile at 50 C, in the presence of 2-pyrazinecarboxylic acid (PCA)
as a cocatalyst. The maximum yield of cyclohexane oxidation products attained was 48%, which is
high in the case of the oxidation of saturated hydrocarbons. The reaction leads to the formation of a
mixture of cyclohexyl hydroperoxide, cyclohexanol and cyclohexanone. When triphenylphosphine is
added, cyclohexyl hydroperoxide is completely converted to cyclohexanol. Consideration of the regioand
bond-selectivity in the oxidation of n-heptane and methylcyclohexane, respectively, indicates
that the oxidation proceeds with the participation of free hydroxyl radicals. The complexes show
moderate activity in the oxidation of alcohols. Complexes 1 and 2 reduce the viability of colorectal
(HCT116) and ovarian (A2780) carcinoma cell lines and of normal dermal fibroblasts without showing
a specific selectivity for cancer cell lines. Complex 3 on the other hand, shows a higher cytotoxicity in
a colorectal carcinoma cell line (HCT116), a lower cytotoxicity towards normal dermal fibroblasts
and no effect in an ovarian carcinoma cell line (order of magnitude HCT116 > fibroblasts > A2780)
First Measurement of the Ti (e,eâ˛) X Cross Section at Jefferson Lab
To probe CP violation in the leptonic sector using GeV energy neutrino beams in current and future experiments using argon detectors, precise models of the complex underlying neutrino and antineutrino interactions are needed. The E12-14-012 experiment at Jefferson Lab Hall A was designed to perform a combined analysis of inclusive and exclusive electron scatterings on both argon (N=22) and titanium (Z=22) nuclei using GeV-energy electron beams. The measurement on titanium nucleus provides essential information to understand the neutrino scattering on argon, large contribution to which comes from scattering off neutrons. Here we report the first experimental study of electron-titanium scattering as double-differential cross section at beam energy E=2.222 GeV and electron-scattering angle θ=15.541^{â}, measured over a broad range of energy transfer, spanning the kinematical regions in which quasielastic scattering and delta production are the dominant reaction mechanisms. The data provide valuable new information needed to develop accurate theoretical models of the electromagnetic and weak cross sections of these complex nuclei in the kinematic regime of interest to neutrino experiments.National Science Foundation (U.S.) (CAREER Grant PHY-1352106
First Measurement of the Ti Cross Section at Jefferson Lab
To probe CP violation in the leptonic sector using GeV energy neutrino beams
in current and future experiments using argon detectors, precise models of the
complex underlying neutrino and antineutrino interactions are needed. The
E12-14-012 experiment at Jefferson Lab Hall A was designed to perform a
combined analysis of inclusive and exclusive electron scatterings on both argon
() and titanium () nuclei using GeV energy electron beams. The
measurement on titanium nucleus provides essential information to understand
the neutrino scattering on argon, large contribution to which comes from
scattering off neutrons. Here we report the first experimental study of
electron-titanium scattering as double differential cross section at beam
energy GeV and electron scattering angle deg,
measured over a broad range of energy transfer, spanning the kinematical
regions in which quasielastic scattering and delta production are the dominant
reaction mechanisms. The data provide valuable new information needed to
develop accurate theoretical models of the electromagnetic and weak cross
sections of these complex nuclei in the kinematic regime of interest to
neutrino experiments.Comment: 6 pages, 5 figures. Version published in Physical Review
Measurement of the Generalized Polarizabilities of the Proton in Virtual Compton Scattering
We propose to conduct a measurement of the Virtual Compton Scattering
reaction in Hall C that will allow the precise extraction of the two scalar
Generalized Polarizabilities (GPs) of the proton in the region of
to . The Generalized Polarizabilities
are fundamental properties of the proton, that characterize the system's
response to an external electromagnetic (EM) field. They describe how easily
the charge and magnetization distributions inside the system are distorted by
the EM field, mapping out the resulting deformation of the densities in the
proton. As such, they reveal unique information regarding the underlying system
dynamics and provide a key for decoding the proton structure in terms of the
theory of the strong interaction that binds its elementary quark and gluon
constituents together. Recent measurements of the proton GPs have challenged
the theoretical predictions, particularly in regard to the electric
polarizability. The magnetic GP, on the other hand, can provide valuable
insight to the competing paramagnetic and diamagnetic contributions in the
proton, but it is poorly known within the region where the interplay of these
processes is very dynamic and rapidly changing.The unique capabilities of Hall
C, namely the high resolution of the spectrometers combined with the ability to
place the spectrometers in small angles, will allow to pin down the dynamic
signature of the GPs through high precision measurements combined with a fine
mapping as a function of . The experimental setup utilizes standard Hall C
equipment, as was previously employed in the VCS-I (E12-15-001) experiment,
namely the HMS and SHMS spectrometers and a 10 cm liquid hydrogen target. A
total of 59 days of unpolarized 75 electron beam with energy of 1100
MeV (6 days) and 2200 MeV (53 days) is requested for this experiment
Measurement of the Ar(e,e p) and Ti(e,e p) cross sections in Jefferson Lab Hall A
The E12-14-012 experiment, performed in Jefferson Lab Hall A, has collected
exclusive electron-scattering data (e,ep) in parallel kinematics using
natural argon and natural titanium targets. Here, we report the first results
of the analysis of the data set corresponding to beam energy of 2,222 MeV,
electron scattering angle 21.5 deg, and proton emission angle -50 deg. The
differential cross sections, measured with 4% uncertainty, have been
studied as a function of missing energy and missing momentum, and compared to
the results of Monte Carlo simulations, obtained from a model based on the
Distorted Wave Impulse Approximation.Comment: 14 pages, 8 figures (submitted to PRC
Measurement of the Cross Sections for Inclusive Electron Scattering in the E12-14-012 Experiment at Jefferson Lab
The E12-14-012 experiment performed at Jefferson Lab Hall A has collected inclusive electron-scattering data for different targets at the kinematics corresponding to beam energy 2.222 GeV and scattering angle 15.54°. Here we present a comprehensive analysis of the collected data and compare the double-differential cross sections for inclusive scattering of electrons, extracted using solid targets (aluminum, carbon, and titanium) and a closed argon-gas cell. The data extend over broad range of energy transfer, where quasielastic interaction, Î-resonance excitation, and inelastic scattering yield contributions to the cross section. The double-differential cross sections are reported with high precision (âź3%) for all targets over the covered kinematic range
Determination of the Titanium Spectral Function From (e, e\u27p) Data
The E12-14-012 experiment, performed in Jefferson Lab Hall A, has measured the (e,eâ˛p) cross section in parallel kinematics using a natural titanium target. In this paper, we report the analysis of the dataset obtained in different kinematics for our solid natural titanium target. Data were obtained in a range of missing momentum and missing energy between 15 Ⲡpm Ⲡ250ââMeV/c and 12 ⲠEm Ⲡ80ââMeV, respectively, and using an electron beam energy of 2.2 GeV. We measured the reduced cross section with âź7% accuracy as a function of both missing momentum and missing energy. Our Monte Carlo simulation, including both a model spectral function and the effects of final-state interactions, satisfactorily reproduces the data
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