1980-1999

Permanent URI for this collection

https://hdl.handle.net/10217/100536

Browse

Now showing 1 - 20 of 339

Open Access
5000 years at Crow's Roost in eastern Colorado
(Colorado State University. Libraries, 1992) McDonald, Robert A., author; Jennings, Calvin H., advisor; Leyendecker, Liston, committee member; Zier, Christian, committee member; Theodoratus, Robert, committee member
Many areas on the high Plains of eastern Colorado have had little prehistoric research conducted on them. One of the areas where there is insufficient information about local prehistory is the area between the two major river drainages, the Arkansas and the Platte. Crow's Roost, a large sandstone cliff, located east of Colorado Springs, Colorado, is situated near this dividing line, known as the Palmer Divide. A series of prehistoric sites at Crow's Roost has been investigated over a period of five years by the Anthropology Department, University of Colorado at Colorado Springs. These investigations indicate that there has been prehistoric occupation at this locality dating back at least 5400 years. This study presents an interpretation of the culture history, and of recent paleoclimatic fluctuations for this locality.
Open Access
A characterization of foodborne illness data, Denver Metropolitan Area, Colorado, 1986-1989
(Colorado State University. Libraries, 1994) Higgins, Charles L., author; Salman, Mowafak Dauod, advisor; Savage, Eldon P., committee member; Reif, John S., committee member
A records search was conducted for foodborne illness complaints to local health departments in the Denver, Colorado Metropolitan Area, defined as Adams, Arapahoe, Boulder, Denver, Douglas, and Jefferson counties. Records for the four-year period beginning with 1986 through 1989 were searched for reports in which two or more persons were alleged to have become ill, experienced similar symptoms and had a common food exposure. Program administrators were interviewed about the procedures used to investigate these complaint reports. The documented cases of foodborne illness in the Denver Metropolitan Area are not sufficient to justify regulatory activities or to target prevention. The assistance of the public, academic and medical community appears to be needed in order to increase the percentage of complaints that can be properly investigated.
Open Access
A cross-cultural comparison of visual landscape preferences for the natural environment
(Colorado State University. Libraries, 1994) Mohd-Shariff, Mustafa Kamal Bin, author; Haas, Glenn E., 1951-, advisor; Wallace, George E., committee member; Lakey, Jeff, committee member; Taylor, Jonathan G., committee member
The purpose of this study was (1) to identify significant differences in the landscape preferences for the natural environments of Caucasian, Hispanic, Black, Native, and Asian American students at Colorado State University, (2) to identify and compare the underlying perceptual dimensions of their preferences, and (3) to compare the effectiveness of the Kaplans' Informational Processing Model of Environmental Preferences predictors on the landscape preferences of each group. The study found that all groups rated the mountain category highest and the grassland category lowest. However, within categories, Native Americans and Caucasians rated mountain and grassland categories significantly higher than Blacks or Asians. Though there were no statistically significant differences, Blacks and Asians rated the city park category relatively higher than Native Americans and Caucasians. Hispanics did not show significant differences from any other group in this study, in mean preference ratings for any of the three environment types depicted. Four perceptual dimensions were found in the mountain category. These were labelled (1) Partially Screened Views, (2) Rock Formations, (3) Enclosed Views, and (4) Exposed Rocks. In the grassland category, there were only two perceptual dimensions - (1) Pathways and (2) Buttes/ Escarpments. Some significant group differences were noted among these dimensions. In utilizing the Kaplans' Informational Processing Model of Environmental Preference, it was found that Complexity and Mystery correlated highly with the landscape preferences of all groups. A multiple regression analysis of the predictors found that they have significant effects on the preferences of all groups and predicted the preferences of all groups, except for Blacks, in similar manner.
Open Access
A flood frequency derivation technique based on kinematic wave approach
(Colorado State University. Libraries, 1987) Cadavid, Luis Guillermo, author; Obeysekera, J. T. B., advisor; Salas, Jose D., committee member; Schumm, Stanley Alfred, 1927-, committee member
The present study deals with the derivation of a methodology to obtain a flood frequency distribution, for small ungaged watersheds, where the overland flow phase is considered to be an important timing component. In the hydrological literature, this technique comprises three components: a rainfall infiltration model, an effective rainfall-runoff model and the probabilistic component. The study begins with a review of the Geomorphological Instantaneous Unit Hydrograph (GIUH), in order to establish its applicability to the aforementioned type of watersheds. Some effective rainfall-runoff models currently used in the practice of hydrology, like the GIUH and models based on Kinematic Wave approach, lack the required features or do not consider all possible responses within the watershed. Therefore, a new model is developed and calibrated, based on Kinematic Wave approach, for a first order stream with two symmetrical lateral planes. The model is conformed by analytical and approximate solutions, the latter improved via regression analysis. The formulated model is used along with a statistical distribution for the effective rainfall intensity and effective duration, in order to derive the flood frequency distribution technique through the probabilistic component. The structure of the equations considered in the different components imposes a numerical algorithm to compute the flood frequency distribution curve for a given watershed. The derived technique is proved for hypothetical and real watershed configurations, showing its capability to forecast flood frequency curves for ungaged watersheds and to account for the influence of parameters on the physics of flood formation. Actual watersheds are conceived as first order streams with two symmetrical planes.
Open Access
A K-ϵ turbulence model for predicting the three-dimensional velocity field and boundary shear in closed and open channels
(Colorado State University. Libraries, 1995) Hafez, Youssef Ismail, author; Gessler, Johannes, advisor; Thompson, Erik, advisor; Molinas, Albert, committee member; Bienkiewicz, Bogusz, committee member; Georg, Kurt, committee member
To view the abstract, please see the full text of the document.
Open Access
A multi-level code comprehension model for large scale software
(Colorado State University. Libraries, 1996) Vans, A. Marie, author; von Mayrhauser, Anneliese, advisor; Bieman, James, committee member; Olender, Kurt, committee member; Volbrecht, Vicki, committee member
For the past 20 years researchers have studied how programmers understand code they did not write. Most of this research has concentrated on small-scale code understanding. We consider it necessary to design studies that observe programmers working on large-scale code in production environments. We describe the design and implementation of such a study which included 11 maintenance engineers working on various maintenance tasks. The objective is to build a theory based on observations of programmers working on real tasks. Results show that programmers understand code at different levels of abstraction. Expertise in the application domain, amount of prior experience with the code, and task can determine the types of actions taken during maintenance, the level of abstraction at which the programmer works, and the information needed to complete a maintenance task. A better grasp of how programmers understand large scale code and what is most efficient and effective can lead to better tools, better maintenance guidelines, and documentation.
Open Access
A paleohydrologic investigation in the vicinity of Harpers Ferry, West Virginia
(Colorado State University. Libraries, 1992) Fuertsch, Susan Jane, author; Wohl, Ellen E., 1962-, advisor; Salas, J. D. (Jose D.), committee member; Stednick, John, committee member
A paleohydrologic investigation of the Shenandoah River in the vicinity of Harpers Ferry, West Virginia, was conducted in response to the recent periodic floods that devastate the community. The study reach was approximately 7.5 km long and consisted of thirty-two surveyed cross-sections. Gaging stations established in 1895 at Millville, West Virginia and in 1882 at Harpers Ferry, West Virginia record flows ranging from a maximum of 6,509 m³s¯' , to a minimum of 2 m³s¯'. The average annual peak discharge for a seventy-year water record was 1,244 m³s¯'. Botanical flood evidence preserved as adventitious sprouts, tree scars and eccentric rings were documented in thirty-seven trees. A flood chronology established from these data extended from 1896 to 1955 after which no botanical indicators were found. Botanical indicators did not extend the systematic record, but they did provide an accurate, although not complete, flood chronology. The completeness of the botanical flood record is highly Sedimentological flood evidence was limited within the study area due to the influence of a humid-temperate climatic regime, which is not conducive to the stratigraphic preservation of individual flood depositional units. Human habitation of the area began in 1733; therefore, qualitative historical records were plentiful. Various historical records were cross-referenced to yield the most complete flood history. The correlation between the various sources was extremely high, demonstrating the comprehensiveness of the record. The historical flood record extends from 1748 to the beginning of the systematic record in 1896. The ability to determine accurate flood stages from paleoflood indicators varied highly. Botanical indicators were found to yield very inaccurate and inconsistent flood stages, and only minimum values of flood stage could be obtained from these data. Historical data did yield accurate stages; however, these stages did not necessarily yield accurate discharge values, depending upon the stationarity and hydraulic complexity of the area.
Open Access
A personal symbolism
(Colorado State University. Libraries, 1984) Ash, Lori Jean, author; Dormer, James T., committee member; Orman, Jack L., committee member; Ellerby, David A., committee member; Lakin, Barbara L., committee member
To view the abstract, please see the full text of the document.
Open Access
A road: poetry in painted landscape
(Colorado State University. Libraries, 1992) Haskins, David, author; Dietemann, David L., advisor; Yust, Dave, 1939-, committee member; Ellerby, David A., committee member; Tremblay, Bill, committee member
Landscapes reflected through the passing of time, light that is real "now", is only a memory a second later. Those memories that catch my mind's eye are what I attempt to hold, to examine, to understand through the painting process. My paintings allow those memories to become real once again and revisited.
Open Access
A search for spiritual integration
(Colorado State University. Libraries, 1997) Keyton, Lisa M., author; Yust, Dave, 1939-, advisor; Dietemann, David L., committee member; Gill, Ann M., committee member; Erskine, Nancy, committee member
My paintings are about a spiritual journey. They act as a visual description as well as a vehicle for the journey itself. For me this journey has included an exploration of utopian visions and a spiritual ideal, as well as the struggle to integrate spirituality into my life. I consider contextual issues and the process of painting as being equally important and integral aspects of these paintings. Contextually this body of work represents an exploration into a "sense of place" and "ambiguous organic forms". This sense of place or environment is not physical, it is a phenomena I perceive while I am in a meditative state. The ambiguous organic forms in my paintings act as metaphors representing myself. Introducing these forms into a sense of place allows me to explore the relationship I have with my spiritual issues and my environment. For me the processes involved with painting helps facilitate the retrieval of memories, emotions and sensations, it soothes, stimulates and mesmerizes, creating a haven for expressing the inner recesses of my soul.
Open Access
A timeless vision
(Colorado State University. Libraries, 1996) Niles, Kathryn M., author; Dormer, James T., advisor; Ellerby, David A., committee member; Mitchell, Carol A., committee member; Simons, Stephen R., committee member
Landscape and figure are timeless, universal, and venerable motifs that compel constant and continued examination. This group of works employs form, movement, and spatial relations that are elements evident in both themes. I approach my subjects with a history of memories, an awareness of my surroundings, and my psychological state at the moment. These portrayals of life as I experience it may, in a sense, all be seen as self-portraits.
Open Access
A uses and gratification study of public radio audiences
(Colorado State University. Libraries, 1982) Bluebond, Scott D., author; Phillips, Dennis D., advisor; Bruner, Howard D., committee member; Pendell, Sue D., committee member
This thesis sought to find out why people listen to public radio. The uses and gratifications data gathering approach was implemented for public radio audiences. Questionnaires were sent out to 389 listener/contributors of public radio in northern Colorado. KCSU-FM in Fort Collins and KUNC-FM in Greeley agreed to provide such lists of listener/contributors. One hundred ninety-two completed questionnaires were returned and provided the sample base for the study. The respondents indicated they used public radio primarily for its news, its special programming, and/or because it is entertaining. Her/his least likely reasons for using public radio are for diversion and/or to transmit culture from one generation to the next. The remaining uses and gratifications categories included in the study indicate moderate reasons for using public radio. Various limitations of the study possibly tempered the results. These included the sample used and the method used to analyze the data. Conducting the research necessary for completion of this study made evident the fact that more research needs to be done to improve the uses and gratifications approach to audience analysis. The identification of the uses and non-uses of public radio have helped lay a foundation for future research in this area.
Open Access
Advective-diffusive gaseous transport in porous media: the molecular diffusion regime
(Colorado State University. Libraries, 1993) Farr, John Merritt, author; McWhorter, David B., advisor; Weeks, Edwin P., 1936-, committee member; Sunada, Daniel K., committee member; Lenz, Terry G., committee member
Traditional mathematical models for advective-diffusive transport in porous media fail to represent important physical processes when fluid density depends on composition. Such is the case for gas mixtures comprised of species with differing molecular masses, such as found in the vadose zone near chlorinated hydrocarbon sources. To address problems of this nature, a more general advection-diffusion (A-D) model is presented, which is valid for porous media with permeabilities exceeding 10-10 cm2 (where Klinkenberg and Knudsen effects are negligible). The new mathematical model is derived by thermodynamic means, based on identifying the meaning of Darcy's advective reference velocity in terms of a weighted average of species drift velocities~ The resulting model has no additional parameters, and introduces no additional complexity or nonlinearity when compared to the traditional A-D model most commonly used in hydrology and environmental science. Because the form of traditional A-D models is retained, the new formulations fit readily into existing numerical simulators for the solution of subsurface transport problems. The new model is equivalent to the Dusty-Gas Model of Mason et al. (1967) for cases where the molecular diffusion regime prevails and pressure, temperature, and forced diffusion are negligible. Further support of the model is provided by hydrodynamic analysis, accounting for the diffusive-slip flux identified by Kramers and Kistemaker (1943). The new model is analytically compared to two existing A-D models, one from the hydrology literature, where Darcy's law is assumed to yield a mass-average velocity, and one from the chemical engineering literature, where Darcy's law is assumed to yield a mole-average velocity. Significant differences are shown to exist between the three transport models. The new model is shown to match closely with the experimental data of Evans et al. (1961a), while the existing A-D models are shown to fail in this regard.
Open Access
African American parental values and perceptions toward children's playfulness
(Colorado State University. Libraries, 1997) Porter, Carolyn A., author; Bundy, Anita C., advisor
Since play is the primary occupation of children, and parents have a significant influence in children's lives, it is important to understand the values, beliefs, and childrearing goals of parents in a multicultural society. This study explored the relationship between African American parents' values and beliefs about playfulness and their children's observed playfulness. Forty-seven African American parents from a middle socioeconomic background and their children participated in this study. Observational assessments, the Test of Playfulness (ToP; Bundy, 1997) and the Children's Playfulness Scale (CPS; Barnett, 1990) were used to measure a child's playful approach. Parents completed questionnaires about their children's playfulness (CPS), and their children were observed during free play (ToP). The findings revealed that African American parents shared similar values about playfulness to parents from other cultures. African American parents valued the social and joyful aspects of playfulness highly, whereas items reflecting humor were valued the least. Also, the CPS and ToP are both valid measures of playfulness with African American parents and their children. The results suggested that mothers may be more accurate in judging children's playfulness than fathers. Cultural influences, parental experience, and parents' developmental goals may be contributing factors. Discussion on the significance of the results, recommendations for future research, and a review of African American theoretical conceptions, family characteristics, parental beliefs, and the relationship of play and culture are highlighted.
Open Access
Air and medium temperatures for Alstroemeria 'Atlas' and 'Monika'
(Colorado State University. Libraries, 1987) Keil, Linda Sue, author; Goldsberry, Kenneth L., advisor; Hanan, Joe J., committee member; Ross, Cleon, committee member
Alstroemeria cultivars 'Atlas' and 'Monika' were grown in four 25.4 m2 fiberglass-covered greenhouse compartments at the W.D. Holley Plant Environmental Research Center, Colorado State University. Each compartment contained two raised redwood benches subdivided into four 75 x 105 cm plots with buffer zones at either end of the bench, Individual benches had replicated plots of cooled and noncooled substrate treatments. The cooled plots contained seven loops of .625 cm OD Biotherm tubing buried 15 cm beneath the pea gravel surface. A thermostatically-controlled cooling system supplied cold water, upon demand, in an attempt to maintain a medium temperature of 11°C. Compartments were heated to 10° to 11°C during night periods, and the following daytime temperature regimes were established: Compartment A, 14° to 20°C; Compartment B, 20° to 26°C; Compartment C, 23° to 28°C; and Compartment D, 17° to 23°C. A night break was provided with incandescent lamps when natural daylengths were less than 12 hours. Developing cultivar rhizomes were transferred from 10 cm pots to the bench plots on November 18, 1985. The first flower data were taken on February 10, 1986, then collected every other day and summarized weekly during the next 52 weeks. Parameters measured included: stem length, flower grade, and total production. Data were analyzed as a split-split plot design with media treatments randomized within each pair of plots. Total flower production of 'Atlas' in all compartments was 1.6 times as great as 'Monika'. Significantly larger numbers of flower stems were produced in the cooled substrate of compartments A and D. The results provided evidence that the greatest production of 'Atlas' and 'Monika' occurred with average daytime temperatures of 20°C combined with an average medium temperature of 12°C to 14°C. Consequently, the cooled medium treatment coupled with cooler air temperatures allowed production to continue virtually year-round. The warmer daytime temperatures of compartments B and C increased the flower quality. However, the higher production in compartments A and D far outweighed the advantage that warmer temperatures contributed to quality. The flower quality of 'Monika' was considerably less than that of 'Atlas' in all temperature treatments. Warmer daytime temperatures also contributed to longer stems. 'Atlas' and 'Monika' stems from compartment C averaged a maximum of 13 cm longer than those from the remaining compartments. 'Atlas' stems were significantly longer than those of 'Monika' in all compartments. A five week sub-trial was conducted to determine air temperature effects on Alstroemeria inflorescence characteristics. Parameters measured included: number of cymes per stem, cyme length, stem thickness, and number of buds per cyme. Data were analyzed as a split plot design. No significant differences were observed for number of cymes per stem and stem thickness between compartments, although 'Atlas' had thicker stems than 'Monika'. A significant trend toward increasing cyme length with increasing daytime temperature was evident in both cultivars. Significantly more buds were produced on stems of both cultivars in compartment D (i.e., 20°C average day air temperature) compared to all other compartments.
Open Access
Alkaline/peracetic acid as a pretreatment of lignocellulosic biomass for ethanol fuel production
(Colorado State University. Libraries, 1998) Teixeira, Lincoln Cambraia, author; Crews, Donald L., advisor; Schroeder, Herbert A., committee member; Linden, James C., committee member; Wangaard, Frederick F., committee member
Peracetic add is a lignin oxidation pretreatment with low energy input by which biomass can be treated in a silo type system for improving enzymatic digestibility of lignocellulosic materials for ethanol production. Experimentally, ground hybrid poplar wood and sugar cane bagasse are placed in plastic bags and a peracetic acid solution is added to the biomass in different concentrations based on oven-dry biomass. The ratio of solution to biomass is 6:1; after initial mixing of the resulting paste, a seven-day storage period at about 20 °C is used in this study. As a complementary method, a series of pre-pretreatments using stoichiometric amounts of sodium hydroxide and ammonium hydroxide based on 4-methyl-glucuronic acid and acetyl content in the biomass is been performed before addition of peracetic acid. The alkaline solutions are added to the biomass in a ratio of 14:1 solution to biomass: the slurry is mixed for 24 hours at ambient temperature. The above procedures give high xylan content substrates. Consequently, xylanase/beta- glucosidase combinations are more effective than cellulase preparations in hydrolyzing these materials. The pretreatment effectiveness is evaluated using standard enzymatic hydrolysis and simultaneous saccharification and cofermentation (SSCF) procedures. Hybrid poplar wood pretreated with 15 and 21% peracetic acid based on oven- dry weight of wood gives glucan conversion yields of 76.5 and 98.3%, respectively. Sugar cane bagasse pretreated with the same loadings gives corresponding yields of 85.9 and 93.1%. Raw wood and raw bagasse give corresponding yields of 6.8 and 28.8%, respectively. The combined 6% NaOH/15% peracetic acid pretreatments increase the glucan conversion yields from 76.5 to 100.0% for hybrid poplar wood and from 85.9 to 97.6% for sugar cane bagasse. Respective ethanol yields of 92.8 and 91.9% are obtained from 6% NaOH/15% peracetic acid pretreated materials using recombinant Zymomonas mobilis CP4/pZB5. Peracetic acid pretreatment improves enzymatic digestibility of hybrid poplar wood and sugar cane bagasse. Based on reduction of acetyl groups in the two lignocellulosic materials, alkaline pre-pretreatments are helpful in reducing peracetic acid requirements in the pretreatment and consequently diminishing growth inhibition of the bacteria that was observed using higher peracetic acid loadings.
Open Access
Allegory and metaphor in tableware
(Colorado State University. Libraries, 1999) Amador, Susan, author; Getty, Nilda C. Fernández, advisor; Dormer, James T., committee member; Fahey, Patrick G., committee member; Valdez, Norberto, committee member
Silver tableware contains the surfaces and familiar cognitive references ripe for story telling with relief, developed by chasing and repousse. The elitist connotations present in the material attract the viewer into close proximity to the work and functionality fosters an intimate relationship. The human tendency towards rituals surrounding ingesting ceremonial food and spiritually elevating drugs devise ingenious accouterments that signal entry into the ritual space, tableware being one of indicators of access. The tableware in this thesis work present allegories with diverse content, from direct, intimate function to paradox. Personal experiences, widespread in their commonality, embody a narrative significance that relates to the holloware form chosen for the particular relief images. As John Keats said "A man's life of any worth is a continual allegory-and very few eyes can see the mystery of his life ... "
Open Access
An exhibition of twenty-three original works of art
(Colorado State University. Libraries, 1980) Benedict, James Michael, author; Dormer, James T., advisor; Dietemann, David L., committee member; Sanford, Kern, committee member
The concern of this thesis is a personal translation of light and form into an interplay of forces that animate the objects or shapes beyond the picture plane. This poetic rhythm of object and space is created by delicate intrusions of geometry on the shapes. These intrusions allow the open space and light to penetrate the image or object but do not dictate its specified shape. The images suggest volume, but they are not hallowed out from space; rather they are projected from space through the interaction of light on form. I have examined these elements in terms of organic forms and also mechanical forms.
Open Access
An implicit method for water wave problems
(Colorado State University. Libraries, 1983) Aston, Martha B., author; Thomas, J. W. (James William), 1941-, advisor; Zachmann, David W., committee member; Schubert, Wayne H., committee member
This paper presents an implicit scheme for numerically simulating fluid flow in the presence of a free surface. The scheme couples numerical generation of a boundary-fitted coordinate system with an efficient solution of the finite difference equations. The method solves the two dimensional Navier-Stokes equations by applying an implicit backward in time difference scheme which is linearized by Taylor series expansion about the known time level to produce a system of linear difference equations. The difference equations are solved by an Alternating-Direction-Implicit procedure which defines a sequence of one dimensional block tridiagonal matrix equations. A standard block elimination scheme solves the one dimensional equations. For each time step, solutions for all equations are calculated simultaneously and noniteratively. Preliminary solutions of free surface fluid flow in an open channel are presented. These solutions are examined to define initial stability criteria for the numerical scheme.
Open Access
An overview of the Fort Collins park system emphasizing City Park as it relates to the development of the community
(Colorado State University. Libraries, 1996) Tunner, Carol, author; Held, R. Burnell, advisor; Aukerman, Robert, committee member; Leyendecker, Liston E., committee member
Through an overview of the history of the early park system of Fort Collins, Colorado, it is shown that City Park has been a cohesive stimulus over the years in helping to define and maintain the character of the growing city. What happened in the past becomes the segue to the present, and ultimately to the future. In order to preserve this family oriented community character and maintain a healthy balance for its citizens, the historical character of City Park should be the basis for its restoration and preservation. A city out of balance demolishes or sacrifices its past for its present with no thought of its future.....the best of the past is irreplaceable.