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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Forest Fires in Western Europe in 1987

Le Canut, Philippe 01 January 1993 (has links)
No description available.
2

Application of Pheasant Census Methods in Cache County, Utah

Zorb, Gordon L. 01 May 1951 (has links)
An inventory of the stock on hand is a basic step in management. This is true whether the field be business, land, or wildlife management. It is a marginal business man who ignores the basic step of inventory. In the history of wildlife management, however, it has not been unusual to find the cart before the horse. This is not to say that the wildlife manager is, or has been, marginal. His business was inherited ready-made, but often in a bankrupt condition. The problems were there, but not the background of records, techniques, or methodology to cope with them. Often management, like Topsy, “just growed.”
3

Soil Moisture Recharge in Stands of Quaking Aspen and Gambel Oak in Central Utah

Boynton, James L. 01 May 1968 (has links)
Soil moisture recharge was studied in quaking aspen and Gambel oak forest areas of central Utah. The rate, timing, and duration of the recharge period was observed. Soil moisture readings were taken periodically throughout the winter of 1966 -1967. Soil moisture recharge begins in October and continues until May. The period of most rapid increase in recharge is between February and May. This corresponds to a rapid decrease in the zenith angle of the sun at the surface of the area and also to a decrease in cloud cover over the area. Deep soils and high infiltration capacities prevent surface runoff from the area. Both detention storage and retention storage capacity of the soils are high. Soil freezing was not present during the winter months. Some patchy soil freezing is found in the spring but it is not extensive enough to influence the recharge phenomenon.
4

An Analysis of Counties and Municipalities Which Did Not Participate in the Land and Water Conservation Fund Act of 1965 Utah: 1965-1970

Bair, Lyle A. 01 May 1974 (has links)
Characteristics of nonparticipating Utah counties and municipalities in the Land and Water Conservation Fund Act of 1965 were studied. Specific objectives studied were: (1) program awareness, (2) program understanding, and (3) reasons for nonparticipation from 1965 to 1970. A telephone survey was conducted of all nonparticipating counties, all nonparticipating municipalities larger than 2500 population and a simple random sampling of municipalities smaller than 2500 population. Results were compared on a governmental unit and regional basis. The survey determined that, as a whole, less than 45 percent of nonparticipating Utah counties and municipalities were aware of the program. The greatest awareness was among the large municipalities of region one and the least awareness was among the small municipalities of region two. County awareness was similar in both regions. Significant differences in program awareness occurred only when small municipalities were compared with large municipalities and counties. Generally, the surveyed governmental units aware of the program had a low degree of program understanding, particularly with regards to who administered the program in Utah. Reasons given for nonparticipation were primarily: (1) no need for parks, (2) unable to provide the local matching share of a grant, (3) did not want to become involved with the federal government, and (4) lack of community leadership. As a whole, a significant number of governmental units not aware of the program would seek federal assistance if they had a recreation resource to develop.
5

The Contribution of Summer Tourism to the Utah Economy

Brakel, William D. 01 May 1969 (has links)
The increase in household income attributed to expenditures by Utah motor vehicle tourists from June 15 to September 5, 1969, was estimated using income multipliers from input-output analysis. Tourist expenditures were gathered through the distribution of postage-paid diaries to non-residents entering Utah. Expenditures were also segregated for Cache County, Utah. The income multipliers from state and county input-output models were used to estimate the impact of applying the state model to county data. Approximately 927,250 tourist parties to Utah spent an estimated $37,842,81 increasing household income $65,018,557. Likewise, approximately 67,709 tourist parties spent an estimated $798,966 in Cache County. The income multipliers from the county model indicated a $1,063,728 increase in household income in Cache County, while the state model estimated this increase to be 44 percent greater.
6

The Influence of Atmospheric Dust and Foliar Leachates on the Chemical Quality of Throughfall in Northern Utah

Parent, Dennis R. 01 May 1972 (has links)
In the summer of 1971 a research project was carried out in an attempt to determine the influence of dust and leachates on rainfall quality . Open precipitation collectors , collectors under polyethylene screens, collectors under Douglas-fir (Pseudotsuga menziesii) and juniper (Juniperus scopulorum) , and leaf analyses were used to determine the relative effects of these two processes by which chemicals are incorporated into the rainwater . All samples were analyzed for sodium (Na+) , calcium (Ca++), magnesium (Mg++), potassium (K+) , and available phosphorus. Under the trees , sodium concentrations increased as much as three times the amount found in the open, calcium was 13 to 16 times greater, magnesium concentrations doubled, and potassium increased as much as 50 times that which occurred in the open rainfall. Calcium was the only cation studied in which the leaching process was important. Increased chemical loads of all other cations were mainly due to dust adhering to the tree canopy as wind passed through it and later being washed off by rainwater.
7

The Influence of Selected Wood Characteristics and Composites Production Parameters on the Sorption Behavior of Wood Materials

Neimsuwan, Trairat 01 December 2007 (has links)
The goal of this research was to investigate the influence of selected wood characteristics and composites production parameters on the sorption behavior of wood materials. A better understanding of the sorption behavior of different wood structures and types could be useful in protecting wood against wood deterioration. The differences among tree ring locations within the stem cross-section have not been explained in terms of sorption behavior. The purpose of the first task was to investigate the effect of differences among earlywood, latewood, and tree ring location within the stem crosssection on the water vapor sorption. A loblolly pine (Pinus taeda) tree was cut into earlywood and latewood from the 2nd to 50th tree rings. A sorption kinetics test was conducted from 11% to 89% RH. Results showed that earlywood had higher sorption rates and diffusion coefficients than latewood, while outer tree rings had higher sorption rates and diffusion coefficients than inner tree rings. An understanding of sorption behavior of individual fibers with varying refiner pressure is necessary to better engineer wood fiber-based composites. The second task was to investigate water vapor sorption of refined fiber as affected by steam pressure using small-scale measurements. Juvenile and mature loblolly pine wood was refined at 2 to 18 bar of steam pressure. Fiber properties were determined by Scanning Electron Microscope (SEM), Dynamic Contact Angle (DCA), X-ray Diffraction (XRD), and a water activity meter. A sorption kinetics test was conducted from 11% to 89% RH. Higher rates of sorption were found in juvenile fiber refined under low steam pressure. Higher water activity and lower cystallinity was found at low-steam-pressure-refined fibers. The volume of oriented strandboard (OSB) produced has significantly increased over the last few decades. Wood, resin, and wax play a key role in manufacture and inservice properties. How resin and wax affect the water vapor sorption behavior of resinated and waxed strands remain unclear. The third task was to investigate the effect of processing parameters on the sorption behavior of wood strands under varying environmental conditions. Loblolly pine strands were created with 2 to 4% and 0.5 to 1.5% for resin and wax loading. The resinated strand was pressed with different platen temperatures (120, 160, and 200°C) and compression rates (1.05 and 1.65). A sorption kinetics test was conducted from 11% to 89% RH. Higher resin and wax loading levels resulted in reduced water vapor sorption in early sorption periods. Higher press platen temperatures and compression rates also decreased the sorption properties of resinated loblolly pine strands. Wax loading had more influence on sorption properties than resin loading. Press platen temperatures had more influence on sorption behavior than compression rate.
8

Wildfire Risk Assessment and Community Wildfire Protection in the Chilhowee Mountain Area of Blount County, East Tennessee

Chimchome, Piyarat 01 May 2008 (has links)
The growing Wildland Urban Interface community in the Chilhowee Mountain area of Blount County, Tennessee, like many other forested areas in the mountains and hills of East Tennessee, was identified by officials of the Tennessee Division of Forestry as being a high risk area for wildfire. The purpose of this research was to help wildfire managers better understand how to facilitate wildfire protection and mitigation in the Chilhowee Mountain area. A mail survey was sent to the 474 property owners in the communities of Campers Paradise, Happy Valley, and Top of the World. The survey contained 33 questions related to wildfire risk, property characteristics, residential status, experience with wildfire, fire risk perception, and preferences for wildfire reduction strategies. A total of 159 property owners participated in the survey with an overall response rate of 35%. The data were weighted to represent the residential status of the property owners (resident, absentee, and lot owners). Homeowners were more likely to perceive higher risk severity and feel more vulnerable than lot owners and they do not see a wildfire affecting them personally as much as their property or possessions. Perceived risk severity and risk vulnerability was positively correlated with fire risk reduction behaviors for all property owners. The reasons given for not implementing protective measures were (in rank order) vacation home/not living there, cost, age/physical ability, lack of fire fighting equipment/water, time, only so much one can do, and neighbors/others pose risks. Two-thirds of the property owners believe there should be no restriction on construction in areas highly susceptible to wildfire, however, almost three out of four indicated it should be required that home buyers be informed when a house they are considering for purchase is in a fire risk zone. There is a considerable need for agencies to work collaboratively in order to develop effective wildfire protection programs in communities. With a multi-agency team, a strong, coordinated message can be delivered to WUI communities. For wildfire risk mitigation to be effective over the long run, a community must be able to sustain involvement in wildfire risk reduction strategies into the future.
9

Establishment, Growth, Spread, and Ecological Impacts of <em>Microstegium vimineum</em> in Central Hardwood Forests

Marshall, Jordan M. 01 August 2007 (has links)
Microstegium vimineum is an annual exotic grass common through the Southeastern United States. Adding M. vimineum to native plant communities may alter future forest composition through inhibiting the growth and influencing recruitment of seedlings into larger size classes, as well as significantly altering vertical structure and community richness, which may influence the distribution of insects. The main objectives of these studies were to 1) establish how different mineral soil and litter disturbances, in combination with various forest canopy coverage, influence the establishment, growth, and spread of M. vimineum, 2) quantify effects of competition between M. vimineum and native hardwood seedlings, and 3) identify the influence of M. vimineum on insect community structure and distribution. As percent canopy cover decreased, M. vimineum mean length and mean number of nodes increased. Also, as soil temperature and soil moisture increased, M. vimineum percent cover increased. Individual seedlings spread further from established populations in both the litter removal and the mineral soil disturbance and litter removal treatments than in the control. The apparent connection between soil disturbance and invasion by M. vimineum provides further impetus for careful planning and use of haul road and skid trails. There was a reduction in A. rubrum and L. tulipifera leaf area as a result of competition with M. vimineum, which was likely due to competition for moisture. Quercus rubra did not display any differences in leaf characteristics as a result of M. vimineum competition. As a result of reductions in growth for A. rubrum and L. tulipifera, competitive impacts imposed by M. vimineum may alter the rate at which these species are recruited into larger size classes. This may change future forest composition, and have ecological and economic consequences. In areas with M. vimineum, there were significantly more insects collected than in areas without M. vimineum. These increases in abundance likely resulted from 2.5 times greater plant cover due to the addition of M. vimineum to the plant communities. However, it should be noted that focusing on a single taxonomic group, such as insects, might not provide an adequate measure of exotic species impacts.
10

Characterizing Strength and Fracture of Wood Micropillars Under Uniaxial Compression

Zhang, Xinan 01 August 2008 (has links)
The structure of the actual wood cell wall is very complex and it consists of several layers. Some research has been done to measure the mechanical properties of wood cell wall. For example, the hardness and modulus of wood cell wall was estimated using a nanoindentation test. But the mechanical contribution of wood cell wall is not fully understood and documented in the literature. Understanding the micro mechanical properties of the wood cell wall are paramount because of the potential for applications in cellulose nano-composites research and development. The focus of this research was to investigate the essential of the strength and fracture of wood cell walls by uniaxial micro-compression test. Keranji and loblolly pine were chosen to perform the micro-compression tests. After initial sample preparation by microtoming, a novel method for sample preparation was adopted. The cylindrical shaped micro pillars were milled using a Focused Ion Beam (FIB) while each pillar was milled in a single wood cell wall. The beam voltage of this FIB system was 30 KV. After measuring the dimension of the micropillar through analyzing the SEM images by ImageJ software, the uniaxial compression test on the micro pillar was conducted using a Nano II Indenter system with a 10 micrometers diameter flat tip. The loading rate of 20 nm/s was used to obtain the load-displacement curves. As a result, the yield stress of keranji cell wall was 136.5 MPa and the compression strength was 160 MPa. The yield stress of loblolly pine cell wall was 111.3 MPa and the compression strength was 125 iv MPa. The fracture behavior of wood micropillar confirmed that wood cell wall also is a brittle type of material. KEY WORDS: wood, cell wall, loblolly pine, keranji, focused ion beam (FIB), scanning electron microscopy (SEM), micropillar, uniaxial micro-compression test, fracture behavior.

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