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A Conductor's Guide to Harrison Birtwistle's "Entr'actes and Sappho Fragments"

Description: Entr'actes and Sappho Fragments (1964) by English Composer Harrison Birtwistle represent extended notation, complex meters, and extended instrumental techniques. After World War II, the style and techniques of musical composition evolved considerably and musical trends began to continuously change. Conducting contemporary compositions requires new approaches in conducting methods. This paper examines a) introduce important elements of Birtwistle's compositions in the 1960, b) include an updated score of Entr'actes and Sappho Fragments (notated by the author), and c) provide a performance guide to the work.
Date: August 2019
Creator: Jang, Hyeyoun
Partner: UNT Libraries

Summary of the Research Progress Meeting

Description: This summary of the research progress meeting on March 18, 1948 covers the following topics: (1) Proton-proton scattering at 7 Mev; (2) Some animal experiments with 90 Mev neutrons; and (3) Yields of spallation products of antimony.
Date: March 18, 1948
Creator: Folden, M.F.
Partner: UNT Libraries Government Documents Department

Progress in recoil spectrometers for separation of fast-nuclear-reaction products

Description: A review is presented of electromagnetic instruments used for detection and separation of heavy nuclear species emitted from or recoiling from targets in fusion, spallation or fission processes. In the case of fusion reactions, the nuclei, called evaporation residues, are emitted in a narrow cone about zero degree and hence have to be separated from the beam. The beam separation process is a major function of the apparatus.
Date: January 1, 1981
Creator: Enge, H A
Partner: UNT Libraries Government Documents Department

Linear Scaling 3D Fragment Method for Large-Scale ElectronicStructure Calculations

Description: We present a linear scaling 3 dimensional fragment (LS3DF)method that uses a novel decomposition and patching scheme to do abinitio density functional theory (DFT) calculations for large systems.This method cancels out the artificial boundary effects that arise fromthe spatial decomposition. As a result, the LS3DF results are essentiallythe same as the original full-system DFT results with errors smaller thanthe errors introduced by other sources of numerical approximations. Inaddition, the resulting computational times are thousands of timessmaller than conventional DFT methods, making calculations with 100,000atom systems possible. The LS3DF method is applicable to insulator andsemiconductor systems, which covers a current gap in the DOE's materialsscience code portfolio for large-scale ab initio simulations.
Date: October 16, 2006
Creator: Wang, Lin-Wang; Zhao, Zhengji & Meza, Juan
Partner: UNT Libraries Government Documents Department

Microscopic Calculation of Fission Fragment Energies for the 239Pu(nth,f) Reaction

Description: We calculate the total kinetic and excitation energies of fragments produced in the thermal-induced fission of {sup 239}Pu. This result is a proof-of-principle demonstration for a microscopic approach to the calculation of fission-fragment observables for applied data needs. In addition, the calculations highlight the application of a fully quantum mechanical description of scission, and the importance of exploring scission configurations as a function of the moments of the fragments, rather than through global constraints on the moments of the fissioning nucleus. Using a static microscopic calculation of configurations at and near scission, we have identified fission fragments for the {sup 239}Pu (n{sub th}, f) reaction and extracted their total kinetic and excitation energies. Comparison with data shows very good overall agreement between theory and experiment. Beyond their success as a proof of principle, these calculations also highlight the importance of local constraints on the fragments themselves in microscopic calculations.
Date: October 3, 2011
Creator: Younes, W & Gogny, D
Partner: UNT Libraries Government Documents Department

Reading the Ruptured Word: Detecting Trauma in Gothic Fiction from 1764-1853

Description: Using trauma theory, I analyze the disjointed narrative structure of gothic works from 1764-1853 as symptomatic of the traumatic experience. Gothic novels contain multiple structural anomalies, including gaps in experience that indicate psychological wounding, use of the supernatural to violate rational thought, and the inability of witnesses to testify to the traumatic event. These structural abnormalities are the result of trauma that characters within these texts then seek to prevent or repair via detection.
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Date: August 2016
Creator: Laredo, Jeanette A.
Partner: UNT Libraries

Expansion cooled CO nuclear pumped laser

Description: A series of experiments are proposed to investigate the performance of a fission fragment excited CO laser which utilizes gas dynamic cooling. These experiments will utilize a wall source of fission fragments to provide excitation of CO or CO gas mixtures. A separate investigation will study the effects on the vibrational excitation distribution of CO or CO on gas mixtures with the addition of UF/sub 6/.
Date: January 1, 1978
Creator: Davis, J.F.; Bird, P.F.; Mansfield, C.R. & Helmick, H.H.
Partner: UNT Libraries Government Documents Department

Theory of neutron emission in fission

Description: Neutron emission in fission is usually described in terms of two observables: the energy spectrum of emitted neutrons N(E) and the average number of neutrons emitted per fission, or average neutron multiplicity, /bar v/p. These observables are measured before the residual fission fragments decay toward the valley of ..beta.. stability and are therefore referred to as the prompt neutron spectrum N(E) and the average prompt neutron multiplicity /bar v/p. They are of fundamental importance to the design of macroscopic systems that are driven by the fission reaction, such as thermal or fast reactors. It is the purpose of this paper to describe existing theoretical models for these two observables. Other observables for neutron emission in fission will not be described here due to space limitations. 12 refs., 2 figs.
Date: January 1, 1988
Creator: Madland, D.G.
Partner: UNT Libraries Government Documents Department

Fission fragment angular distributions

Description: Many recent papers have found that calculations with the standard angular distribution formula for fission fragments from compound nuclei do not reproduce the strong anisotropies observed in the decay of high spin systems. They conclude that a noncompound nuclear process must exist for some partial waves and postulate an ad-hoc angular distribution for this process in order to reproduce the strong anisotropies. It is the purpose of this contribtion to demonstrate that much of the data are, in fact, consistent with compound nucleus formation and to emphasize that the standard model is not a generally valid way to calculate fission fragment angular distributions from a compound nucleus.
Date: January 1, 1985
Creator: Bond, P.D.
Partner: UNT Libraries Government Documents Department

The application of position-sensitive phoswich detectors for low-mass fragment detection in an array environment

Description: Large solid angle position-sensitive phoswich detectors have been constructed to replace smaller units in an array for detecting medium mass fragments (Z less than or equal to 15) in nuclear experiments. The position information was obtained from a time analysis method. 5 refs., 9 figs.
Date: September 1, 1988
Creator: Chan, Y.; Chavez, E.; Dacal, A.; Gazes, S.; Harmon, B.A.; Plagnol, E. et al.
Partner: UNT Libraries Government Documents Department

Interpreting multiplicity-gated fragment distributions from heavy-ion collisions

Description: In recent years, multifragmentation of nuclear systems has been extensively studied, and many efforts have been made to clarify the underlying physics. However, no clear consensus exists on the mechanism for multifragmentation. Is the emission of intermediate mass fragments (IMF: 3 {le} Z {le} 20) a dynamical process (brought on by the occurrence of instabilities of one form or another) or a statistical process (i.e. the decay probabilities are proportional to a suitably defined exit channel phase space)? Historically the charge (mass) distribution has played and still plays a very important role in characterizing multifragmentation. Since this subject`s inception, the near power-law shape of the charge and mass distributions was considered an indication of criticality for the hot nuclear fluid produced in light ion and heavy ion collisions. Here, the authors have studied different aspects of the charge distributions. The implications of the experimental evidence presented here are potentially far reaching. On the one hand, the thermal features observed in the n-fragment emission probabilities for the {sup 36}Ar + {sup 197}Au reaction extend consistently to the charge distributions and strengthen the hypothesis of the important role of phase space in describing multifragmentation. On the other hand, they have investigated charge correlation functions of multi-fragment decays to search for the enhanced production of nearly equal-sized fragments predicted in several theoretical works.
Date: February 1, 1997
Creator: Phair, L.; Moretto, L.G.; Rubehn, T.; Wozniak, G.J.; Beaulieu, L.; Tso, K. et al.
Partner: UNT Libraries Government Documents Department

Quantitative determination of {sup 252}Cf.

Description: Sealed {sup 252}Cf sources in the microCurie to milliCurie range are routinely used in industry and research. At present, no reliable analytical method is available for precise determination of the activity. Very strong sources can be analyzed by neutron counting but the error is large. The authors propose to use gamma-ray spectroscopy for such analysis. In particular, high-energy gamma rays (above 1 MeV) of fission fragments in equilibrium with the source are very convenient because they have little absorption in materials surrounding the source. They have measured the gamma/alpha ratio for {sup 252}Cf with an uncertainty of better than 5%. The experiment involved the preparation of several thin {sup 252}Cf sources, alpha pulse height analysis, determination of alpha decay rate, and the measurement of gamma singles spectrum with a well shielded germanium spectrometer. The measured ratio and the gamma ray spectroscopy of unknown samples can provide the activity of {sup 252}Cf in these samples.
Date: May 1, 2002
Creator: Ahmad, I.; Moore, E. F.; Greene, J. P.; Porter, C. E. & Felker, L. K.
Partner: UNT Libraries Government Documents Department

Multifragmentation at intermediate energy: Dynamics or statistics

Description: In this report the authors consider two contradictory claims that have been advanced recently: (1) the claim for a predominantly dynamical fragment production mechanism; and (2) the claim for a dominant statistical and thermal process. They present a new analysis in terms of Poissonian reducibility and thermal scaling, which addresses some of the criticisms of the binomial analysis.
Date: January 1, 1998
Creator: Beaulieu, L.; Phair, L.; Moretto, L.G. & Wozniak, G.J.
Partner: UNT Libraries Government Documents Department

Report on Radiation Damage Effects in a Titanium Target Under Photon Irradiation

Description: Following the same approach as with the W-Re targets [l], we have calculated the damage induced by photon irradiation (22.1 MeV average energy) in titanium targets. Stefan Roesler calculated, using FLUKA [2] the spallation products, neutrons and fission products from the interaction of the photons with the titanium target. Using these initial values of energies and positions, we calculated the number of defects produced per incoming photon. It should be noted that the threshold displacement energy for defect production of Titanium as measured experimentally is between 21 and 30 eV [3]. We used a value of 25eV. This is a much lower value than for the case of W-alloys (90 eV) which implies a larger defect production for the same deposited energy in the case of Titanium. The number of defects for different neutron energies was calculated using SPECTER [4] Figure 1(a) shows the number of defects as a function of energy for the case of Ti as compared to W, in Figure 1(b). The number of defects is much larger in the Ti case due to the low threshold displacement energy as explained.
Date: August 30, 2002
Creator: Caturla, M J; Roesler, S; Bharadwaj, V K; Schultz, D C; Sheppard, J C; Marian, J et al.
Partner: UNT Libraries Government Documents Department

The Brookhaven Chemonuclear in-Pile Test Loop

Description: Technical report outlining the plan to develop the Brookhaven chemonuclear in-pile test loop because the interest in utilizing reactor radiation energy (fission-fragment recoil and neutron-gamma) for production of chemicals has developed to the point where a loop to study chemonuclear system in a reactor under dynamic conditions is necessary.
Date: April 23, 1962
Creator: Tucker, Walter D.; Waide, C.; Bezler, P. & Steinberg, Meyer, 1924-
Partner: UNT Libraries Government Documents Department

Spontaneous fission

Description: The spontaneous fission (SF) of the heaviest actinides and the transactinides is of particular interest because of the dramatic changes in properties observed in the region of the heavy fermion isotopes and for still heavier elements. The existing experimental information on SF properties including half-life systematics, fragment kinetic-energy and mass-yield distributions, prompt neutron emission, and gamma emission will be reviewed. Possibility for extending studies of SF properties to other regions are considered and the potential for obtaining additional information about low-energy fission properties is discussed.
Date: September 1, 1993
Creator: Hoffman, D. C.
Partner: UNT Libraries Government Documents Department

Studies of complex fragment emission in heavy ion reactions

Description: Our work involves the study of intermediate energy heavy-ion nuclear reactions. This work has two foci. On the one hand, we desire to learn about the properties of nuclear matter under abnormal conditions, in this energy domain, predominately low densities. This purpose runs abreast of the second, which is the study of the relevant reaction mechanisms. The two objectives are inexorably linked because our experimental laboratory for studying nuclear matter properties is a dynamic one. We are forced to ask how nuclear matter properties, such as phase transitions, are reflected in the dynamics of the reactions. It may be that irrefutable information about nuclear matter will not be extracted from the reaction work. Nevertheless, we are compelled to undertake this effort not only because it is the only game in town and as yet we do not know that information cannot be extracted, but also because of our second objective. The process leads to an understanding of the reaction mechanism themselves and therefore to the response characteristics of finite, perhaps non-equilibrium, strongly interacting systems. Our program has been: To study energy, mass, and angular momentum deposition by studying incomplete fusion reactions. To gain confidence that we understand how highly excited systems decompose by studying all emissions from the highly excited systems. To push these kinds of studies into the intermediate energy domain, with excitation function studies. And attempt to learn about the dynamics of the decays using particle-particle correlations. In the last effort, we have decided to focus on simple systems, where we believe, definitive statements are possible. These avenues of research share a common theme, large complex fragment production.
Date: January 1, 1992
Creator: Charity, R.J. & Sobotka, L.G.
Partner: UNT Libraries Government Documents Department

Development of a transition-state treatment of multifragmentation

Description: For the nuclear multifragmentation problem, several statistical models have been developed in recent years, based on excitable fragments within a specified freeze-out volume. Such a scenario is of direct relevance to the study of dilute nuclear matter and the formulation of the associated statistical mechanics is relatively simple. Application of such statistical models to the disassembly of a nuclear ''source'' has usually been made by simply assuming that the yield of a given final channel is proportional to the corresponding statistical weight. A principal problem with these approaches is that there is no inherent way of determining the freeze-out volume, which therefore must be prescribed by some argument external to the model. Moreover, the propagation of the fragmenting system from the freeze-out configuration to asymptotia is dependent on how the potential energy is treated. These problems are particularly serious at relatively moderate excitations and they need to be adequately solved before it is possible to clarify such key questions as the transition from the ordinary sequential-binary type of decay characteristics of low excitation to the nearly simultaneous multifragment breakup apparently occurring at high excitation. This unsatisfactory situation has motivated us to develop a refined treatment of statistical multifragmentation based on a suitable generalization of the transition-state approximation for ordinary binary fission. Thus, we consider the irreversible transition of a very excited compound nucleus into a number of prefragments. These prefragments are still interacting and may in general experience significant change during their dynamical evolution subsequent to the transition. The main objective will be to characterize the ''transition state,'' the family of configurations at which the system irreversibly makes the transition into the specified prefragments.
Date: December 1, 1988
Creator: Randrup, J. & Lopez, J.A.
Partner: UNT Libraries Government Documents Department

Thermal and statistical properties of nuclei and nuclear systems

Description: The term statistical decay, statistical or thermodynamic equilibrium, thermalization, temperature, etc., have been used in nuclear physics since the introduction of the compound nucleus (CN) concept, and they are still used, perhaps even more frequently, in the context of intermediate- and high-energy heavy-ion reactions. Unfortunately, the increased popularity of these terms has not made them any clearer, and more often than not one encounters sweeping statements about the alleged statisticity of a nuclear process where the statistical'' connotation is a more apt description of the state of the speaker's mind than of the nuclear reaction. It is our goal, in this short set of lectures, to set at least some ideas straight on this broad and beautiful subject, on the one hand by clarifying some fundamental concepts, on the other by presenting some interesting applications to actual physical cases. 74 refs., 38 figs.
Date: July 1, 1989
Creator: Moretto, L.G. & Wozniak, G.J.
Partner: UNT Libraries Government Documents Department