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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.
31

Water saving mechanisms, a policy analysis

Stautberg, Edward Berwind 03 February 2014 (has links)
Distributed water conservation provides significant benefits to overall water availability, particularly if adopted at a large scale. Conservation strategies, such as rainwater harvesting, xeriscaping, and permeable pavements are desirable because they conserve water, increase recharge near dwellings, and reduce dangerous stormwater runoff. Though conserving water is an admirable goal, justifying retrofits for water conservation mechanisms to existing structures is difficult because water prices are very low in much of the United States. However, stormwater regulations and the increasing implementation of stormwater utilities by cities enable other avenues of adoption for these practices. This thesis reviews water conservation strategies, examines local and state policies, and presents a “model policy”. The model policy design uses a comparative approach to identify useful incentives and aggregates best management and policy practices from several states to serve as a guide and accelerate implementation. / text
32

Response of the citrus fruit-stem system to fruit removing actions

Rumsey, James Warren, 1943- January 1967 (has links)
No description available.
33

The effect of impact and quasi-static force on the physiological weight loss of potato tubes.

Akonoby, Matthew Okafor. January 1973 (has links)
No description available.
34

Network analysis applied to hay harvesting operations.

Coupland, Gary Albert. January 1969 (has links)
No description available.
35

Gastropod diversity in the boreal mixedwood forest of northern Alberta - variation among forest types and response to partial harvesting

Abele, Suzanne E Unknown Date
No description available.
36

Similitude studies of potato harvester digger.

Ramtahal, George H. January 1971 (has links)
No description available.
37

Development of Electromagnetic Micro-Energy Harvesting Device

Patel, Pratik January 2013 (has links)
The use of energy harvesting devices has generated much research interests in recent years. There are numerous energy harvesters available in the market that are piezoelectric, electromagnetic, electrostatic or combination of piezoelectric and electromagnetic. Many of the harvesters have shown great potential but are either severely limited in power generation since they are actually never optimized to its potential. One of the goals of this thesis is to develop an electromagnetic micro-energy harvester that is capable of working at low frequencies (5-30 Hz) and is capable of producing electrical power for small devices. Generally, batteries have been used to power low voltage electronics, however the need for self-sustaining and reliable power source have always been a major issue. This project aims to make a harvester of size AA battery that can be used as a reliable and continuous source of power for bio-medical as well as industrial applications. Firstly, a linear harvester is developed for applications where there is no set natural frequency. The linear harvester consists of a stator and a mover. The stator includes copper coils, outer iron case and delrin holder for the coils while the mover consists of permanent magnets, iron pole and cylindrical rod. The working principles developed are used to optimize and improve the efficiency of energy harvesting system. The linear harvesting system is tested with the permanent magnet to iron pole ratio of 1.25 and permanent magnet to coil ratio of 0.73. The power density of the linear harvester is determined to be 4.44e-4 W/cm3. Thereafter, optimization is done in comsol to improve the performance of the energy harvesting system. The optimized magnet to iron ratio is determined to be 3.175 and permanent magnet to coil ratio of 0.7938. The optimized ratios are used to develop an inertial type non-linear energy harvesting device. The structure of the non-linear harvester is same as the linear one except two stationary magnets are added at the top and bottom of the harvester that act as a non-linear spring. The non-linear harvesting device is tested and the power density of the system is determined to be 2.738e-2 W/cm3. The non-linear harvester was tested at acceleration level of 1g and it was determined that the harvester worked best at natural frequency of 8.66 Hz. The maximum power produced was 38.1 mW. The non-linear type of harvester is easy to assemble and optimize to match ambient natural frequency of numerous vibrating systems. Two frequency tuning methods are looked at for the non-linear energy harvesting system. One is by changing the magnetic air gap and the second is by changing the thickness of the stationary top and bottom magnets. It is determined that changing magnetic air gap is more effective at tuning for a range of natural frequencies. For applications where the natural frequency of the system doesn't exist, such as buoys and beacons at sea, the linear energy harvester works best. For applications where the system vibrates at a certain natural frequency, the non-linear harvester should be used. Finally, this thesis is concluded with a discussion on the electromagnetic micro-harvester and some suggestions for further research on how to optimize and extend the functionality of the energy harvesting system.
38

Gastropod diversity in the boreal mixedwood forest of northern Alberta - variation among forest types and response to partial harvesting

Abele, Suzanne E 11 1900 (has links)
Terrestrial gastropods are important decomposers, herbivores, and prey items in forest systems and constitute a poorly understood element of forest biodiversity in Canada. I studied gastropod assemblages in relation to forest cover type and in response to variable retention harvesting in the mixedwood boreal forest of northwestern Alberta. Gastropods were sampled using two methods: board traps and collection of litter samples. Gastropod assemblages were influenced by canopy composition, with most gastropods of the mixedwood showing a strong affinity for broadleaf dominated forests. Tree species mixture influenced gastropod distribution; basal tree area of either conifer or broadleaf trees was generally associated with gastropod distribution within a stand. Harvesting was clearly associated with increased abundance of many species 9 years post-harvest, however, abundance declined for other species. Harvesting with retention helps to maintain pre-harvest boreal gastropod assemblages and will likely conserve boreal gastropod assemblages if used as a tool for biodiversity management. / Conservation Biology
39

Physical factors influencing mechanical detachment of apples /

Burkholder, James Richard, January 1965 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute, 1965. / Vita. Abstract. Includes bibliographical references (leaves 52-54). Also available via the Internet.
40

Optimal harvesting of continuous age structured populations /

Smith, Steven J. January 1988 (has links)
Thesis (Ph. D.)--Oregon State University, 1988. / Typescript (photocopy). Includes bibliographical references (leaves 84-85). Also available on the World Wide Web.

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