The objective of this study was to optimize the cultural and environmental conditions necessary to produce high quality basil in a semi-arid climate during summer. Basil grown in a retractable roof greenhouse (RRGH) and full sun over two years using production systems including rockwool, containers, raised beds, vertical towers, and soil was evaluated based on biomass accumulation, morphological characteristics and quality. Photosynthetic response of basil to temperature and light was tested in a growth chamber to determine the optimum conditions that enhance photosynthesis and increase productivity. Biomass accumulation and quality of basil were affected by environment and cultural practices, with the largest quantities of highest quality basil produced in rockwool or raised beds in the RRGH. The response of basil to light and temperature indicated that highest photosynthesis during summer occurred between temperatures of 25 to 35 °C at a light intensity of 1500 μmol m⁻¹ s⁻¹.

Since Ferrero SpA established a manufacturing plant in Brantford, Ontario, there has been considerable interest in developing a hazelnut industry locally. One of the issues that needs to be overcome is to supply large numbers of suitable plants rapidly. They can be micropropagated, and then grown in the nursery. Usually, it takes two years to grow suitably sized plants in the nursery. This thesis investigated methods to grow suitably sized plants in one year and evaluated the nursery systems from financial aspect. Hazelnut seedlings were planted in ellepots and plastic pots, and then subjected to three treatments: grown in a retractable roof greenhouse, treated with root pruning technology or grown in outdoor environment. Also, two transplant timings were tested: the fall of 2011 and the spring of 2012. The results showed that pot type did not influence the growth of hazelnut seedlings. The retractable roof greenhouse increased growth and the root pruning technology changed the seedlings root structure but not their growth. Transplant timing did not affect the seedlings growth in the first year in the field. The retractable roof greenhouse has the potential to produce two crops of seedlings in one growing season compared to one crop in the outdoor nursery. The estimated cost per seedling under retractable roof greenhouse was $9.31, which was $1.95 cheaper than outdoor. / Ontario Centres of Excellence and Ontario Ministry of Agriculture, Food and Rural Affairs

Yes / The duration of most collar arrangements provided by governments to encourage early investment in infrastructure, renewable energy facilities, or other projects with social objectives are finite, not perpetual. We extend the previous literature on collar-style arrangements by providing an analytical solution for the idle and active values, as well as the investment triggers, for projects where collars are either finite-lived or retractable. What is the difference between these types of arrangements with their perpetual counterpart? Lots, including different vega signs, and substantially different values for different current price levels. Often, finite and retractable collars justify earlier investment timing than perpetual collars. In general, we demonstrate that the finite-lived and retractable versions have a significant impact on optimal behavior, relative to the perpetual case. An important consideration when negotiating the floors, ceilings, and duration (or signalling the expected duration) of a finite or a retractable collar is the current price level of the output and its expected volatility over the life of the contract. / Carried out within the funding with COMPETE reference n. POCI-01-0145-FEDER-006683 (Artur Rodrigues) and POCI-01-0145-FEDER-006890 (Paulo J. Pereira), FCT/MEC’s (Fundação para a Ciência e a Tecnologia, I.P.) financial support through national funding and by ERDF through the Operational Programme on Competitiveness and Internationalization - COMPETE 2020 under the PT2020 Partnership Agreement.

Over the last decade there has been a worldwide increase in the use of retractable roofs for stadia. This increase has been based on the flexibility and better economic performance offered by venues featuring retractable roofs compared to those with traditional fixed roofs. With this increased interest an evolution in retractable roof systems has followed. This dissertation is concerned with the development of concepts for retractable roof systems. A review is carried out to establish the current state-of-the-art of retractable roof design. A second review of deployable structures is used to identify a suitable retractable structure for further development. The structure chosen is formed by a two-dimensional ring of pantographic bar elements interconnected through simple revolute hinges. A concept for retractable roofs is then proposed by covering the bar elements with rigid cover plates. To prevent the cover plates from inhibiting the motion of the structure a theorem governing the shape of these plate elements is developed through a geometrical study of the retractable mechanism. Applying the theorem it is found that retractable structures of any plan shape can be formed from plate elements only. To prove the concept a 1.3 meter diameter model is designed and built. To increase the structural efficiency of the proposed retractable roof concept it is investigated if the original plan shape can be adapted to a spherical surface. The investigation reveals that it is not possible to adapt the mechanism but the shape of the rigid cover plates can be adapted to a spherical surface. Three novel retractable mechanisms are then developed to allow opening and closing of a structure formed by such spherical plate elements. Two mechanisms are based on a spherical motion for the plate elements. It is shown that the spherical structure can be opened and closed by simply rotating the individual plates about fixed points. Hence a simple structure is proposed where each plate is rotated individually in a synchronous motion. To eliminate the need for mechanical synchronisation of the motion, a mechanism based on a reciprocal arrangement of the plates is developed. The plate elements are interconnected through sliding connections allowing them mutually to support each other, hence forming a self-supporting structure in which the motion of all plates is synchronised. To simplify the structure further, an investigation into whether the plate elements can be interconnected solely through simple revolute joints is carried out. This is not found to be possible for a spherical motion. However, a spatial mechanism is developed in which the plate elements are interconnected through bars and spherical joints. Geometrical optimisation of the motion path and connection points is used to eliminate the internal strains that occur in the initial design of this structure so a single degree-of-freedom mechanism is obtained. The research presented in this dissertation has hence led to the development of a series of novel concepts for retractable roof systems.

Scatter and random coincidences are of significant concern in Positron Tomography because they lead to the misrepresentation of the activity distribution in the final image. In this regard, interplane septa have long been used in ring positron tomographs to suppress the acquisition of photons oblique to the scan planes. The septa extend from the face of the detector array to the edge of the field of view. Not only do the septa block photons scattered oblique to the scan planes and singles originating in different planes, but they also result in a decreased count rate sensitivity of the tomograph to true coincidence photons. In this work, the Monte Carlo technique has been employed to study the effect of "septa shadowing" with respect to septa length in order to determine an optimal septa length. Sensitivity parameters have been derived by the use of Noise Equivalent Count (NEC) Rate Analysis, as well as count rate sensitivity analysis in order to balance the counting and imaging performance of the system. In addition, energy spectra, sinogram profiles and scatter fraction results are presented to quantify the effects of septa length on the trues, scatter and randoms contributions of the data collected by the scanner. It is concluded that the highest NEC rate is achieved with positron tomographs with no septa and operating in 3D mode. / Thesis / Master of Science (MS)

Modification of TST-14 MC glider, calculation of flight envelope, distribution of lift on the wing, calculation of loading cases of the wing, strength check of choosen construction nodes, design of the landing gear retraction mechanism, setting up loading of landing gear according to ULKM, strength check of landing gear

This thesis studies the design of an electro-hydraulic landing gear and brakes control system of a trainer aeroplane. In the first part there is a basic draft of the landing gear kinematics and its loads during gear retraction, flight and landing. Braking conditions are also analysed. The thesis then focuses on the design of hydraulic circuits and their control. Simulations for studying the dynamic characteristics of the braking proportional valve and the course of plane braking were created in Simulink. There is also a brief section about reliability of the proposed system.

This diploma thesis deals with design of retractable landing gear for Rapid 600 aircraft. The main purpose of this thesis is to analyze different retraction options for front and main landing gear and resulting selection of suitable variants. The thesis is consequently concerned with design of selected options including proposal of automatic landing gear control system and specifying the features and characteristics of this system. In the thesis there is also included the analysis of critical flight conditions which could be detected by this system.

This diploma thesis describes the design of retractable landing gear for the NG-4 ultralight aircraft. Its main part consists of general principle of gear retraction, kinematics analysis, load calculation and structural analysis, material selection and means of controlling by pilot. The thesis contents marginally the typology of aircraft landing gears and their evolution.

No description available.