3,118 research outputs found
Two prehistoric archeological sites in Egyptian Nubia
The Yale University Prehistoric Expedition to Nubia was part of UNESCO\u27S international program to salvage the monuments of Nubia, with the direct aid of the Department of Antiquities of the United Arab RepublicâŠ
Tune Determination of Strongly Coupled Betatron Oscillations in a Fast-Ramping Synchrotron
Tune identification - i.e. attribution of the spectral peak to a particular
normal mode of oscillations - can present a significant difficulty in the
presence of strong transverse coupling when the normal mode with a lower
damping rate dominates spectra of Turn-by-Turn oscillations in both planes. The
introduced earlier phased sum algorithm helped to recover the weaker normal
mode signal from the noise, but by itself proved to be insufficient for
automatic peak identification in the case of close phase advance distribution
in both planes. To resolve this difficulty we modified the algorithm by taking
and analyzing Turn-by-Turn data for two different ramps with the beam
oscillation excited in each plane in turn. Comparison of the relative
amplitudes of Fourier components allows for automatic correct tune
identification. The proposed algorithm was implemented in the Fermilab Booster
B38 console application and successfully used in tune, coupling and
chromaticity measurements.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012, New Orleans, Louisian
Observation of Instabilities of Coherent Transverse Ocillations in the Fermilab Booster
The Fermilab Booster - built more than 40 years ago - operates well above the
design proton beam intensity of 4x10**12 ppp. Still, the Fermilab neutrino
experiments call for even higher intensity of 5.5x10**12 ppp. A multitude of
intensity related effects must be overcome in order to meet this goal including
suppression of coherent dipole instabilities of transverse oscillations which
manifest themselves as a sudden drop in the beam current. In this report we
present the results of observation of these instabilities at different tune,
coupling and chromaticity settings and discuss possible cures.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012, New Orleans, Louisian
Electron heating by sheaths in radio frequency discharges
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Short Musculoskeletal Function Assessment:normative data of the Dutch population
The Short Musculoskeletal Function Assessment (SMFA) is widely used in both research and clinical practice. Despite its frequent use, normative data of the SMFA have remained limited. Aim of this study was to gather normative data for the Dutch SMFA (SMFA-NL). The SMFA-NL consists of two indices (function index and bother index) and four subscales (upper extremity dysfunction, lower extremity dysfunction, mental and emotional problems, and problems with daily activities). A total of 900 patients were invited to fill in the SMFA-NL. Six age groups (18-24, 25-34, 35-44, 45-54, 55-64, and 65-75 years) were constructed. Analysis of variance, t tests, and regression analyses were used to assess age and gender effects. The response rate was 97 %. There was a significant difference between men and women in scores on all indices and subscales (range p <0.001 to p = 0.002), except for the upper extremity dysfunction subscale (p = 0.06). A significant interaction effect was found between gender and age for the upper extremity dysfunction subscale; a larger decrease in score with increasing age was observed for women, compared with men. Significant differences were found between age groups for the bother index (p <0.001), lower extremity dysfunction subscale (p = 0.001), and the problems with daily activities subscale (p = 0.002). Significant differences in SMFA-NL scores were found between men and women and between different age groups. These SMFA-NL normative data provide an opportunity of benchmarking health status of participants with musculoskeletal disorders or injuries against their age- and gender-matched peers in the Dutch population
The future of sovereignty in multilevel governance Europe: a constructivist reading
Multilevel governance presents a depiction of contemporary structures in EU Europe as consisting of overlapping authorities and competing competencies. By focusing on emerging non-anarchical structures in the international system, hence moving beyond the conventional hierarchy/anarchy dichotomy to distinguish domestic and international arenas, this seems a radical transformation of the familiar Westphalian system and to undermine state sovereignty. Paradoxically, however, the principle of sovereignty proves to be resilient despite its alleged empirical decline. This article argues that social constructivism can explain the paradox, by considering sovereign statehood as a process-dependent institutional fact, and by showing that multilevel governance can feed into this process
Resonance ionization spectroscopy of thorium isotopes - towards a laser spectroscopic identification of the low-lying 7.6 eV isomer of Th-229
In-source resonance ionization spectroscopy was used to identify an efficient
and selective three step excitation/ionization scheme of thorium, suitable for
titanium:sapphire (Ti:sa) lasers. The measurements were carried out in
preparation of laser spectroscopic investigations for an identification of the
low-lying Th-229m isomer predicted at 7.6 +- 0.5 eV above the nuclear ground
state. Using a sample of Th-232, a multitude of optical transitions leading to
over 20 previously unknown intermediate states of even parity as well as
numerous high-lying odd parity auto-ionizing states were identified. Level
energies were determined with an accuracy of 0.06 cm-1 for intermediate and
0.15 cm-1 for auto-ionizing states. Using different excitation pathways an
assignment of total angular momenta for several energy levels was possible. One
particularly efficient ionization scheme of thorium, exhibiting saturation in
all three optical transitions, was studied in detail. For all three levels in
this scheme, the isotope shifts of the isotopes Th-228, Th-229, and Th-230
relative to Th-232 were measured. An overall efficiency including ionization,
transport and detection of 0.6 was determined, which was predominantly limited
by the transmission of the mass spectrometer ion optics
Dialkyl and Methyl-Alkyl Zirconocenes: Synthesis and Characterization of Zirconocene-Alkyls That Model the Polymeryl Chain in Alkene Polymerizations
Zirconocene precatalysts with sterically bulky alkyl groups were designed as model systems for the propagating species in zirconocene-catalyzed alkene polymerization. Specialty alkyllithium reagents Li(CH_2CEt_3) and Li(CH_2CMe_2CH_2Ph) were prepared and utilized in the synthesis of dialkyl and methyl-alkyl zirconocenes of the form CpCp^*ZrR_2, Cp_2Zr(CH_3)(R), and CpCp^*Zr(CH_3)(R) (Cp = (η^5-C_5H_5); Cp^* = (η^5-C_5Me_5); R = CH_2CMe_3, CH_2SiMe_3, CH_2CEt_3, CH_2CMe_2CH_2Ph). These new zirconocene alkyls were isolated and fully characterized by NMR spectroscopy and in some cases by X-ray diffraction. The molecular structures determined display the bent-sandwich coordination mode common for zirconocenes. The steric influence of the alkyl group on the observed structural parameters is reflected in slightly expanded CâZrâC or CâZrâCl angles in the equatorial plane and long zirconiumâalkyl bond distances
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