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Algorithms and implementations of APT resonant control system

Description: A digital signal processor is implemented to control resonant frequency of the RFQ prototype in APT/LEDA. Two schemes are implemented to calculate the resonant frequency of RFQ. One uses the measurement of the forward and reflected fields. The other uses the measurement of the forward and transmitted fields. The former is sensitive and accurate when the operation frequency is relatively far from the resonant frequency. The latter gives accurate results when the operation frequency is close to the resonant frequency. Linearized algorithms are derived to calculate the resonant frequency of the RFQ efficiently using a fixed-point DSP. The control frequency range is about 100kHz for 350MHz operation frequency. A frequency agile scheme is employed using a dual direct digital synthesizer to drive klystron at the cavity`s resonant frequency (not necessarily the required beam resonant frequency) in power-up mode to quickly the cavity to the desired resonant frequency. This paper will address the algorithm implementation, error analysis, as well as related hardware design issues.
Date: August 1, 1997
Creator: Wang, Yi-Ming & Regan, A.
Partner: UNT Libraries Government Documents Department

A Selected List of Music for Solo Clarinet and Clarinet with Piano by Taiwanese Female Composers Composed between 1986 and 2015: The Investigation of a Neglected Repertory with an Annotated Bibliography

Description: Clarinet works by Taiwanese female composers are not well researched or catalogued, and to date, and no comprehensive research codifies this subcategory in Taiwan or elsewhere. A comprehensive research and bibliography is necessary to the international community. It is hoped that through this annotated bibliography, readers will gain a deeper understanding of this genre. This study contains a brief history of Taiwan's Western music history, the female composers' history in Taiwan, and literature review. A total of twenty compositions by eighteen different Taiwanese female composers are discussed in the annotated bibliography, including thirteen for unaccompanied clarinet and seven for clarinet and piano. Information includes a brief biography of the composer, the date of composition, duration, premiere, dedication, commission, location of the score, difficulty and commentary on the piece.
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Date: May 2017
Creator: Wang, Yi-Wen
Partner: UNT Libraries

Life History of Mayatrichia ponta Ross (Trichoptera: Hydroptilidae) in Honey Creek, Turner Falls Park, Oklahoma

Description: The life history and ontogenetic microhabitat change of Mayatrichia ponta Ross were investigated in Honey Creek, Turner Falls Park, Murray Co., Oklahoma, U.S.A. from August 1994 to August 1995. The shape of larval cases changed from a small cone to a cylinder. M. ponta had an asynchronous multivoltine life history with considerable cohort and generation overlap; five generations were estimated. The development rate was reduced in winter. The winter generations of M. ponta had wider head capsule widths (136-165 μm) than summer generations (121-145 μm). The sex ratio of adults was 1.43 ♂ : 1 ♀. Fecundity ranged from 46 to 150 eggs/female. Fifth instar larvae and pupae aggregated on the bottom side of substrates. Early instars were distributed evenly on all sides of substrates. General patterns of ontogenetic microhabitat shift in aquatic insects are categorized as flow mediated, flow independent, and population interactions and other resources mediated.
Date: December 1997
Creator: Wang, Yi-Kuang
Partner: UNT Libraries

EXCESS RF POWER REQUIRED FOR RF CONTROL OF THE SPALLATION NEUTRON SOURCE (SNS) LINAC, A PULSED HIGH-INTENSITY SUPERCONDUCTING PROTON ACCELERATOR

Description: A high-intensity proton linac, such as that being planned for the SNS, requires accurate RF control of cavity fields for the entire pulse in order to avoid beam spill. The current design requirement for the SNS is RF field stability within {+-}0.5% and {+-}0.5{sup o} [1]. This RF control capability is achieved by the control electronics using the excess RF power to correct disturbances. To minimize the initial capital costs, the RF system is designed with 'just enough' RF power. All the usual disturbances exist, such as beam noise, klystron/HVPS noise, coupler imperfections, transport losses, turn-on and turn-off transients, etc. As a superconducting linac, there are added disturbances of large magnitude, including Lorentz detuning and microphonics. The effects of these disturbances and the power required to correct them are estimated, and the result shows that the highest power systems in the SNS have just enough margin, with little or no excess margin.
Date: June 1, 2001
Creator: Lynch, Michael; Kwon, Sung-Il; Regan, Amy & Wang, Yi-Ming
Partner: UNT Libraries Government Documents Department

The Impact of Genetics, Socioeconomic Status, and Lifestyle Factors on Visual Health in an Adult Population

Description: The purpose of this dissertation was to understand how genetics, socioeconomic status (SES), and lifestyle factors influence the development of age-related macular degeneration (AMD), glaucoma, and diabetic retinopathy in an adult population in Dallas County. Two hundred fifty-three older adults participated in this study as the sample. Crosstabulation and binary logistic regression were utilized to analyze the data. Results indicated a disparity among participants' test scores, visual health status, and perceptions of their visual impairment and highlighted the fact that many seniors are not educated about age-related retinal disorders. Furthermore, variables reaching statistical significance were consistent with the literature included race/ethnicity, age, having a family history of both AMD and diabetes, frequency of eye exams, and level of education. The results not consistent with the literature as affecting visual health included health insurance, access to health care, body weight, and smoking status. Recommendations for future study included applied research focusing on determining risk factors, raising awareness, educating, and providing early detection of these diseases among low to middle income Caucasian, African American, and Hispanic older adults.
Date: December 2010
Creator: Mitzel, Gina Marie
Partner: UNT Libraries

Detecting vegetation-precipitation feedbacks in mid-Holocene North Africa from two climate models

Description: Using two climate-vegetation model simulations from the Fast Ocean Atmosphere Model (FOAM) and the Community Climate System Model (CCSM, version 2), we investigate vegetation-precipitation feedbacks across North Africa during the mid-Holocene. From mid-Holocene snapshot runs of FOAM and CCSM2, we detect a negative feedback at the annual timescale with our statistical analysis. Using the Monte- Carlo bootstrap method, the annual negative feedback is further confirmed to be significant in both simulations. Additional analysis shows that this negative interaction is partially caused by the competition between evaporation and transpiration in North African grasslands. Furthermore, we find the feedbacks decrease with increasing timescales, and change signs from positive to negative at increasing timescales in FOAM. The proposed mechanism for this sign switch is associated with the different persistent timescales of upper and lower soil water contents, and their interactions with vegetation and atmospheric precipitation.
Date: March 31, 2008
Creator: Wang, Yi; Notaro, Michael; Liu, Zhengyu; Gallimore, Robert; Levis, Samuel & Kutzbach, John E.
Partner: UNT Libraries Government Documents Department