1,139 research outputs found
Anaerobic digestion of source segregated domestic food waste: performance assessment by mass and energy balance
No full textAn anaerobic digester receiving food waste collected mainly from domestic kitchens was monitored over a period of 426 days. During this time information was gathered on the waste input material, the biogas production, and the digestate characteristics. A mass balance accounted for over 90% of the material entering the plant leaving as gaseous or digestate products. A comprehensive energy balance for the same period showed that for each tonne of input material the potential recoverable energy was 405 kWh. Biogas production in the digester was stable at 642 m3 tonne?1 VS added with a methane content of around 62%. The nitrogen in the food waste input was on average 8.9 kg tonne?1. This led to a high ammonia concentration in the digester which may have been responsible for the accumulation of volatile fatty acids that was also observed.<br/
Laser-induced fluorescence (LIF) of jet-cooled thorium nitride (ThN)
No full textMade available in DSpace on 2019-07-15T22:16:23Z (GMT). No. of bitstreams: 2
3748.pdf: 17797 bytes, checksum: 12a41df70f81153866a374b422ba47ad (MD5)
license.txt: 4802 bytes, checksum: 58353f9dd6876860dd5221f3d7872a95 (MD5)
Previous issue date: 2019-06-19Made available in DSpace on 2020-01-25T19:29:30Z (GMT). No. of bitstreams: 4
3748.pdf.txt: 1606 bytes, checksum: c4a8383c9a31bea90ce6fa1f213b67ec (MD5)
license.txt: 4802 bytes, checksum: 58353f9dd6876860dd5221f3d7872a95 (MD5)
3748.pdf: 17797 bytes, checksum: 12a41df70f81153866a374b422ba47ad (MD5)
1375516.pptx: 4527734 bytes, checksum: 03b0f650a3549a850c5891c1889f520e (MD5)
Previous issue date: 2019-06-19Due to their higher melting point and metal ion density compared to their oxide counterparts, actinide nitrides are promising candidates for nuclear fission sources in nuclear reactors. While thorium mononitride (ThN) is a possible fission source in thorium-based reactors, few studies on ThN have been conducted. Previous ThN studies have characterized gas-phase rovibronic transitions through resonance-enhanced multiphoton ionization (REMPI) and laser-induced fluorescence (LIF) spectroscopic methods[1]. These uncalibrated low-resolution survey spectra, however, were mostly unanalyzed. A calibrated, higher resolution spectrum was recorded for one vibronic band ([20.9]1.5-X) and spectroscopic constants were reported for the ground state and the electronically excited state[1]. More recently, a second band ([18.0]1.5-X) has been observed at high-resolution and used to examine the fine and hyperfine structure of ThN(X)[2]. In the present study, ThN was jet-cooled to approximately 100K and LIF spectra were recorded over the range 20,000-21,300 cm. A tellurium (Te) cell was heated to 650 C and its absorbance spectrum was used for spectral calibration. Data and analyses of the observed ground state and excited states of ThN will be presented.
[1] M.C. Heaven, B.J. Barker, I.O. Antonov, J. Phys. Chem. A, 118 (2014) 10867-10881.
[2] A. T. Le, S. Nakhate, T. Nguyen, T. C. Steimle, M. C. Heaven, J. Chem. Phys., submitte
The electronic spectrum of the UO2 molecule
No full textThe electronic spectrum of the UO2 Molecule has been determined using multiconfigurational wave functions together with the inclusion spin-orbit coupling. The molecule has been found to have a (5fphi)(7s), (3)Phi(2u), ground state. The lowest state of gerade symmetry, H-3(4g), corresponding to the electronic configuration (5f)(2) was found 3330 cm(-1) above the ground state. The computed energy levels and oscillator strengths were used for the assignment of the experimental spectrum in the energy range 17000-19000 and 27000-32000 cm(-1)
FLUORESCENCE DEPLETION SPECTRA FOR THE CN-Ne VAN DER WAALS COMPLEX.
No full text1. Y. Lin and M. C. Heaven, J. Chem. Phys. 94, 5765 (1991) 2. S. Fei and M. C. Heaven, J. Chem. Phys. 98, 753 (1993) 3. S. Fei and M. C. Heaven, Proc. SPIE. 1858, 286 (1993)Author Institution: Emory University, Atlanta, GA 30322In previous , laser excitation spectra were recorded for the and transitions of CN-Ne. Analysis of the B-X system was straightforward, providing information concerning the anisotropy of the ground and excited state potential energy surfaces. Spectra for the A-X system revealed the presence of the predissociation channels and . The product state distributions resulting from these predissocations were determined, but the partially resolved CN-Ne A-X bands resisted analysis. Double resonance techniques, using depletion of fluorescence from known lines of the B-X system, are being used to simplify and assign the A-X fine structure. Analyses of these spectra, the derivation of potential energy surface parameters, and interpretations of the predissociation dynamics will be presented. Work supported by NSF under grant CHE-932009
ROTATIONALLY RESOLVED SPECTROSCOPY OF THE B1__ X1_+ AND C1_+_ X1_+ ELECTRONIC BANDS OF CaO
No full text"The and transitions of CaO, at energies below 30,000 , were previously investigated by Lagerqvistfootnote{A. Lagerqvist, textit{Arkiv F{\""o}r Fysik} textbf{underline{8}}, 83, 1954}. The arc source used in that work yielded spectra at energies above 30,000 that were too congested for analysis. In the present study we have used jet-cooling of CaO to extend the characterization of the and band systems up to 35,000 . Analyses of these data and spectroscopic constants will be reported. This work is being carried out in support of two-color photoionization studies of the cation, where the higher energy vibronic levels of the B and C states are used as the first excitation step."Made available in DSpace on 2016-01-05T20:02:37Z (GMT). No. of bitstreams: 3
1035.pdf: 20596 bytes, checksum: aff1a8109e4ad74bef3768afdabc72cc (MD5)
379845.pptx: 5478482 bytes, checksum: fdfbcb1624efec0fb87345ef04c61243 (MD5)
license.txt: 4813 bytes, checksum: 715c4321821a960fa1a1e91d2ac7ebce (MD5)
Previous issue date: 2
LASER ABSORPTION AND EMISSION SPECTROSCOPY OF THE YELLOW GREEN BAND SYSTEM OF
No full textL.A Kaledin, A. L. Kaledin, and M. C. Heaven. J.M Spectrosc: 179, 246--252 (1996) W. Y. Fan and P. A. Hamilton, diem. Phys Lett. 230, 555--560 (1994) W. J. Balfour dud K S Chandrasekhar, J Mol Spectrosc. 139, 245-252 (1990) L. A Kaledin, I. P. Parrish. and M. C. Heaven, 51-st International Symposium OD Molecular Spectroscopy, paper ME08 (1996)Author Institution: Department of Chemistry, Emory UniversityThe Yellow-Green band system of has been studied using a dual-beam laser absorption technique in a hollow cathode , and conventional emission spectroscopy. The quartz discharge cell for emission spectroscopy consisted of a 5 cm long, 2 mm internal diameter capillary similar to that used for a velocity modulation emission The discharge was modulated at 25-125 kHz by a power supply which produced a bipolar me wave. Samples of in Ar were flowed slowly through the cell from the center of the capillary and symmetrically pumped out via the electrodes. The Yellow-Green band system was observed previously in the and spectra of . Molecular parameters and internuclear distances for the [17.9] and states of the and isotopomers will be presented. Work supported by AFOSR and the Mission Research Corporation
Ab initio investigations of the excited electronic states of caoca
No full textChemical bonding in alkaline earth hypermetalic oxides is of fundamental interest. Previous Ab initio studies of CaOCa predicted a centrosymmetric linear geometry for both the ground state and the low lying triplet state\footnote{B. Ostojic{\'i}, P.R. Bunker, P. Schwerdtfeger, Artur Gertych, and Per Jensen, Journal of Molecular Structure 1023 (2012) 101–107.}. However, there have been no reports concerning the higher energy singlet and triplet states. The present work is focused on characterization of the potential energy surface (PES) of the excited state (assuming a centrosymmetric linear geometry) and obtaining predictions for the vibronic transitions. We employed the multireference configuration interaction (MRCISD) method with state-averaged, full-valence complete active space self-consistent field (SA-FV-CASSCF) wavefunctions. In these calculations, the active space consisted of ten valence electrons in twelve orbitals, where all the valence electrons were correlated. Contributions of higher excitation and relativistic effects were taken into account using the Davidson correction and the Douglas-Kroll (DK) Hamiltonian, respectively. The correlation-consistent polarized weighed core-valence quadruple zeta basis set (cc-pwCVQZ-DK) was used for all three atoms. The full level of theory is abbreviated as SA-FV-CASSCF (10,12)-MRCISD-Q/cc-pwCVQZ-DK. The calculations were carried out using the MOLPRO2012 suite of programs. For the centrosymmetric linear geometry in all states, initial investigations of one-dimensional radial cuts provided equilibrium bond distances of 2.034 {\AA}, 2.034 {\AA}, and 1.999 {\AA} for the , , and states, respectively. The vertical excitation frequency of the optical transition was calculated to occur at 14801 \wn . These predictions were followed by spectroscopic searches by Heaven et al. Indeed, rotationally resolved vibronic progressions were recorded in the vicinity of the predicted electronic band origin. Calculation of the three-dimensional PES showed that the potential minimum in the corresponds to a bent equilibrium geometry with a bond angle of (C point group, where the electronic symmetry is ). This result suggests that the Ca-O bonds in CaOCa possess covalent character in the excited state and ionic character in the ground state. The current results, as well as those from ongoing studies will be presented.Made available in DSpace on 2017-01-26T21:38:28Z (GMT). No. of bitstreams: 3
license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5)
1774.pdf: 23760 bytes, checksum: 5333eb5e02b8384734a27e6c38eb92a6 (MD5)
651058.pptx: 358267 bytes, checksum: 16ab27ca63109f670fa1ec3ad8519453 (MD5)
Previous issue date: 2016-06-2
Perturbations Of The A’<sup>1</sup>Π And C<sup>1</sup>Σ<sup>+</sup> States Of Cao
No full textThe electronic structure of CaO is complex due to the large number of low-lying energy states and a multitude of rovibronic interactions among them. Several vibrionic bands of the CaO have been identified in the visible region using laser induced fluorescence. Analysis of these rotationally resolved data provides more accurate band origins and rotational constants for levels that were previously determined indirectly using perturbation data. Fluorescence decay lifetime measurements were used to determine the radiative decay rate for the state.
A previously noted homogeneous perturbation of the state was examined to determine the identity of the perturbing state. Dispersed fluorescence spectra and fluorescence decay rate measurements were used to show that the perturbation results from the interaction with a state of symmetry.Made available in DSpace on 2021-09-24T21:09:36Z (GMT). No. of bitstreams: 2
4806.pdf: 18901 bytes, checksum: bb69bc83af9fd860289e821a2b565e47 (MD5)
license.txt: 4802 bytes, checksum: 58353f9dd6876860dd5221f3d7872a95 (MD5)
Previous issue date: 2021-06-22Made available in DSpace on 2022-01-21T16:09:46Z (GMT). No. of bitstreams: 4
4806.pdf.txt: 1154 bytes, checksum: 29c8b32fac12eda65ca1efea4259df02 (MD5)
license.txt: 4802 bytes, checksum: 58353f9dd6876860dd5221f3d7872a95 (MD5)
4806.pdf: 18901 bytes, checksum: bb69bc83af9fd860289e821a2b565e47 (MD5)
TD01_4806.pdf: 241749 bytes, checksum: cebe5b24ea435a659b997ccd3b61e8a6 (MD5)
Previous issue date: 2021-06-2
Index to Let Us Meet in Heaven: The Civil War Letters of James Michael Barr, 5th South Carolina Infantry
No full textThis is an index created by Dr. George Rable for research
The Son and the other stars: Christology and cosmology in the imagination of C.S. Lewis
No full textThis dissertation treats the theory and practice of C. S. Lewis's theological imagination,
focussing upon the imaginative use he made of his professional expertise in medieval and
renaissance literature. Its approach is principally expository rather than an evaluative.
Chapter One outlines the centrality of the imagination to a proper understanding of Lewis's
works.
Chapter Two examines Lewis's own theory of imagination and surveys how he practised it
as a literary critic. We compare and contrast Lewis's theory and practice of imagination
with that of his friend, the theologian, Austin Faffer.
Chapter Three looks in more detail at Lewis's imaginative practice, in particular his
fascination with the images supplied by the seven planets of the Ptolemaic cosmos, which
he termed 'spiritual symbols of permanent value'. We analyse what he meant by 'sprit'
and 'symbol'.
Chapter Four introduces the main argument of the dissertation namely that these seven
spiritual symbols structure the works for which Lewis is best known, the seven 'Chronicles
of Narnia'. We claim to have uncovered the governing imaginative blueprint of the septet.
We address Lewis's capacity for and interest in secrecy and consider why this planetary
theme has remained hitherto undetected.
In Chapters Five to Eleven we take the seven planets in turn and trace the use Lewis made
of them through out his writings. We analyse the planetary symbolism undergirding each
Chronicle and conclude each chapter with an exegesis of the Christological message of each
book so understood.
Chapter Twelve examines factors which motivated Lewis to focus his imaginative energies
upon Ptolemaic cosmology and suggests one particular occasioning factor behind the
composition of the Chronicles. In addition, we consider theological and pedagogical reasons
why he kept silent about the planetary theme. We conclude by indicating certain
consequences that our argument has for future readings of these seven works
- …
