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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

Characterization, Simulation, Analysis and Management of Hydraulic Properties of Greenhouse Plant Growth Substrates

Chen Lopez, Jose Choc January 2011 (has links)
The greenhouse industry is facing significant challenges such as the demand for more efficient use of energy and natural resources and prevention of detrimental environmental impacts. Reducing negative environmental impacts can be achieved by utilizing recycled and environmentally friendly products and by optimizing the use of water and root zone substrates. New and advanced root zone substrates are currently tested as substitute for natural soils in greenhouse agriculture. They can be inert non-organic materials such as rockwool and perlite. These are mined products from the earth, and are difficult to dispose after use. Natural substrates such as peat are being consumed faster than being regenerated. A new potential substrate that consists of recycled foamed glass aggregates is considered an alternative, as it is environmentally friendly, non-toxic and disposable. Experiments with foamed glass aggregates and with foamed glass aggregate/coconut coir mixtures indicated that the yield of greenhouse tomatoes was not statistically significant different (α=0.05) when compared to rockwool. To investigate the potential application of recycled glass as a root zone substrate, physical and hydraulic properties were measured. For comparison, the same measurements were completed for rockwool, coconut coir, perlite, and PET/PE fibers as well as for a mixture of coconut coir and recycled glass. The water characteristics (WC) determined for each substrate exhibited distinct air entry potentials, which provided information for irrigation scheduling, water storage and aeration for optimum plant growth conditions. Coconut coir and rockwool exhibited a unimodal shaped water retention curve, while foamed glass aggregates and perlite exhibited bimodal shaped curves. The obtained substrate properties were used as input paramaters for HYDRUS- 2D/3D model to simulate water mass balance and matric potential distributions within a typical growth container of foamed glass aggregates. The simulated matric potential and water content distributions were compared to tensiometer measurements of matric potential in the foamed glass aggregates. The simulations compared favorably with laboratory experiments measured under controlled environmental conditions.
2

Planetárium s kavárnou / Planetarium with coffee

Vlčková, Sabina January 2016 (has links)
Thesis on "Planetarium with coffee" is processed in the form of project documentation for construction. The proposed facility is designed as a two-storeyed without basement with the main ground plan dimensions of 52,8 x 27,47 m and is located near the village Lošov close to Olomouc. The building is operationally divided into a part intended for public entrance and a part for operation and maintenance. Loadbearing structural system is reinforced concrete monolithic skeleton based on monolithic reinforced concrete foundation footings. Ceiling structure consists of reinforced concrete, monolithic, locally supported, cross reinforced floor slab. Vertical external walls are made of ceramic blocks with contact thermal insulation system. Part of the front rounded facade is designed as glass fronted. The building is covered by a warm flat roof. Roof cladding consists of vegetation layers, walkable terrace or non-walkable structure of roof cladding. The planetarium itself is covered by a reinforced concrete dome with a thermal insulation layer of plates of foamed glass. Fillings of doors and windows are made of aluminum profiles with isolating triple glazing. The building meets the requirements for barrier-free use of buildings.

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