Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Camels (1)
- Compounds (1)
- Computer imaging (1)
- Computer programs (1)
- Denitrosation (1)
-
- Diet composition (1)
- Discrete failure (1)
- Disease pests (1)
- Distribution (1)
- Ecological model (1)
- Efficient use of water (1)
- Fertile soil microsites (1)
- Forage quality (1)
- Foraging behavior (1)
- Forest dynamics (1)
- Forest insect (1)
- Groundwater flow systems (1)
- Growth rate (1)
- Herd management (1)
- Igneous plutons (1)
- Irradiation (1)
- N-nitroso (1)
- Optimum soil water usage (1)
- Probability (1)
- Resource allocation (1)
- Root exploitation (1)
- Root proliferation (1)
- Soil temperature regimes. (1)
- Surface topography (1)
- Thermal regimes (1)
Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Groundwater Flow Systems And Thermal Regimes Near Cooling Igneous Plutons: Influence Of Surface Topography, Mark U. Birch
Groundwater Flow Systems And Thermal Regimes Near Cooling Igneous Plutons: Influence Of Surface Topography, Mark U. Birch
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Previous studies of cooling igneous plutons did not consider the possible influence of sloping surface topography. Topographically-driven fluids in high relief terrain, however, are thought to interact with deep buoyancy-driven fluids to produce large lateral-flow systems up to 5 km long and 20 km long in silicic and andesitic volcanic terrain, respectively. In this study, a quantitative investigation of the interaction of topographically-driven and buoyancy-driven fluid flow is conducted through the use of a finite element numerical model to simulate the fluid flow and thermal regimes associated with a cooling igneous pluton in the presence of significant topographic relief. The …
Modeling Forest Dynamics Based On Stand Level Resource Allocation, Geoffrey Candler Poole
Modeling Forest Dynamics Based On Stand Level Resource Allocation, Geoffrey Candler Poole
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
An ecologically based model of forest succession is presented. In the model, trees compete for a share of limited growth resources available from their environment. Competition is reflected by each tree's effect on the resource pool and is not explicitly modeled. Model parameters were fit to field data from subalpine forests of the Rocky Mountains. A technique for estimating model parameters from understory-tolerance rankings and silvical characteristics of each species is also presented. The model's output was consistent with our current understanding of forest dynamics. Emergent properties of the model also mimicked natural processes such as self-thinning, release, and maximum …
Using Computer Imaging To Assess Visual Impacts Of Forest Insect And Disease Pests, Daniel Rabin
Using Computer Imaging To Assess Visual Impacts Of Forest Insect And Disease Pests, Daniel Rabin
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Forest insect and disease pests alter the appearance of trees, thereby impacting visual resources. Because of the complexity of most forest landscapes, the degree of visual impact of pest-infested forest stands is difficult to quantify.
This paper describes a method of measuring visual impacts of pest-infested forest stands. Photographs of healthy Ponderosa pine trees were entered into a computer video-image-processing system. Using this system, images of trees were altered to simulate different degrees of infestation by limb rust, a forest pathogen.
The altered and unaltered images were shown to groups of observers who rated the scenes in terms of "scenic …
Footwall Deformation And Structural Analysis Of The Footwall Of The Willard Thrust Fault, Northern Wasatch Range, Utah, Douglas Scott Neves
Footwall Deformation And Structural Analysis Of The Footwall Of The Willard Thrust Fault, Northern Wasatch Range, Utah, Douglas Scott Neves
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Deformation mechanisms in the footwall of the Willard thrust fault, northern Wasatch Range, Utah, change from dominantly plastic to dominantly cataclastic (both microscopically and macroscopically) in the Ophir Formation and Maxfield Limestone before the thrust begins to ramp laterally upsection southward, just to the north of the North Ogden Canyon field area. This transition in compressional deformation style and mechanism is located within a lateral distance of 3.2-kilometers along the 22-kilometer long trace of the thrust fault.
Between Willard Canyon and North Ogden Canyon penetrative deformation is localized within 200 meters of the thrust surface and is characterized by transposed …
Probability Of Discrete Failures, Weibull Distribution, Mary Jo Hansen
Probability Of Discrete Failures, Weibull Distribution, Mary Jo Hansen
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The intent of this research and these is to describe the development of a series of charts and tables that provide the individual and cumulative probabilities of failure applying to the Weibull statistical distribution. The mathematical relationships are developed and the computer programs are described for deterministic and Monte Carlo models that compute and verify the results. Charts and tables reflecting the probabilities of failure for a selected set of parameters of the Weibull distribution functions are provided.
Origin And Evolution Of Dolostone In The Middle Cambrian Langston Formation, Northern Utah, Mark C. Hall
Origin And Evolution Of Dolostone In The Middle Cambrian Langston Formation, Northern Utah, Mark C. Hall
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Six major generations of dolomite are present within the Cambrian Langston Formation in the Wellsville Mountains and Bear River Range of northern Utah. Identification of dolomite generations and delineation of their relative sequences are based on normal light petrography, cathodoluminescence, staining, chemistry, inferred burial history, and deformation features. The earliest stage is believed to be Middle to Late Cambrian in age. The presence of dolomite rhombs and dolomitized echinoid fragments and peloids suggests that this stage probably formed under sabkha reflux conditions. Extensive nonferroan, polymodal, nonplanar ("xenotopic") dolomite formed next under confined mixing zone conditions. A succeeding generation of pervasive …
Soil Temperature Influence On Water Use And Yield Under Variable Irrigation, Jon M. Wraith
Soil Temperature Influence On Water Use And Yield Under Variable Irrigation, Jon M. Wraith
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The need for efficient use of water resources has increased the importance of optimum soil water usage in agricultural systems. Soil temperature has been shown to be important in influencing the early development of many plant species. Many agricultural regions have suboptimal soil temperature regimes for plant growth, and some cultural practices have been shown to reduce near-surface soil temperatures. The seasonal influence of soil temperature on soil water extraction and aboveground and belowground plant growth under variable irrigation was investigated at the USU Greenville Farm in Logan, UT. Soil surface mulches and buried heat cables were used to modify …
Root Exploitation Of Fertile Soil Microsites, Robert B. Jackson
Root Exploitation Of Fertile Soil Microsites, Robert B. Jackson
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Root exploitation of enriched soil microsites was examined for the tussock grasses Agropyron desertorum and Agropyron spicatum and the shrub Artemisia tridentata. Two mechanisms of exploitation of the microsites were examined: root proliferation and changes in nutrient uptake capacity. One day after nutrient solution was applied to small soil patches, the mean relative growth rate of Agropyron desertorum roots in enriched patches was two to four times greater than for roots of the same plants in soil patches treated with distilled water. This rapid and striking root proliferation occurred in response to N-P-K enrichment as well as to P or …
Management, Foraging Behavior, Diet Composition And Forage Quality Of Free-Ranging But Herded Camels In Ceeldheer District, Central Somalia, Ahmed A. Elmi
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
In Somalia, camel (Camelus dromedarius) survivability and milk production has been higher than for other domestic livestock and contributes substantially to the subsistence of Somali pastoralists. The objective of this research was to study management, foraging behavior and nutrition of camels in their natural habitat to determine how production continues under seasonal nutritional stress.
Management systems of Ceeldheer pastoralists are based on available natural pasture and water. The natural rotation grazing system maintained an ecological equilibrium in the District.
Pastoralists manipulate their herds to suit existing environmental conditions, family needs and labor availability for herding. In herd management, …
A Study Of Denitrosation Of N-Nitroso Compounds By Irradiation With Long-Wavelength Uv Light, Zhenyu J. Wang
A Study Of Denitrosation Of N-Nitroso Compounds By Irradiation With Long-Wavelength Uv Light, Zhenyu J. Wang
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
N-Nitrosamines and N-nitrosamides have been reported to be mutagenic. N-Nitrosamides are direct mutagens that need no activation to be mutagenic, whereas N-nitrosamines need to be enzymatically activated to exert their mutagenicity. Oxidative demethylation of nitrosamines is a commonly accepted activation mechanism. Another pathway of nitroso compounds, denitrosation, has recently been proposed. The mechanism of denitrosation, however, is still unknown.
The purpose of this study was to use a photo -reaction model to explore the possible denitrosation mechanism of N-nitroso compounds. An N-nitrosamine, N-nitrosomorpholi ne (NMOR), and an N-nitrosamide, N-methyl-N'-nitrosoguanidine (MMNG), were irradiated with long-wavelength UV light in the presence of …