Two Arabidopsis lines, 10’4 and 3’1, with partial-repression, constitutively of mitochondrial pyruvate dehydrogenase kinase that could alter dark respiration (Rd) were grown on rockwool to reduce off-gassing from peat that interfered with assessment of Rd. At the rosette stage, Rd and photosynthesis (Pn) at high CO2 were greater than at ambient CO2, and Rd was greater for whole-plant than single leaf measurements due to the contribution of non-laminar tissues. However, whole-plant and leaf Rd and Pn were similar on a leaf-area-basis comparing mutants with controls. Whole-plant, analyses during reproductive stage showed that although, the inflorescence contributed as much as 90% of daily C-gain when the rosette leaves senesced, canopy-Pn on a surface-area-basis at each CO2 level remained similar to those at the rosette stage. At each CO2 level, the transgenic and control lines were similar indicating that the mutation resulted in no direct or indirect effect of Rd or Pn. / Ontario Graduate Scholarship, Green Crop Net Work

Thesis (M. P. A.)--Texas State University-San Marcos, 2005. / "Spring 2005." Electronic version dated 2006. Includes bibliographical references (leaves 70-72).

Thesis (M.Arch.)--University of Hong Kong, 1996. / Includes special report study entitled : Building technology for a new prototype. Includes bibliographical references. Also available in print.

No description available.

This study examined the effects of elevated CO2 and its interaction with drought and nitrogen fertilizer on the growth, production and nodulation of the leguminous crop lentil (Lens culinaris Medic) cultivars ILL7979 and ILL6994 (Idlib 3). Plants were grown under ambient and elevated CO2 at full and limited irrigation conditions in both open top chambers, which were later proven to be unreliable because of CO2 leakage, and tightly sealed and ventilated chambers which were reliable. Destructive harvests at anthesis and at maturity were conducted and results from sealed chambers at maturity showed that above ground dry weight was increased by an average of 12% under elevated CO2, but this increase was not statistically significant.

This thesis presents the nonlinear in-plane behaviour of circular fixed arches subjected to thermal loading only. Due to the nonlinear prebuckling behaviour of arches and its effects, classical buckling theory which is founded on geometric prebuckling linearity can not predict the in-plane buckling of arches accurately. Based on a nonlinear formulation of the strain and displacement relationship and considering constant thermal distributions only, virtual work formulations are used to establish the differential equations of in-plane equilibrium and the statical boundary conditions, from which the nonlinear equilibrium equations are derived in closed form and which are suitable to use in design. By considering the adjacent buckled configurations, the differential buckling equilibrium equations are formulated from the principle of virtual work as well, and the analytical solutions for the nonlinear buckling of fixed arches are obtained. It is shown that nonlinear elastic buckling of a fixed in the plane of it curvature can not occur when it is subjected to thermal loading only, except if the arch is as a straight column. By using the algebraic representation of nonlinear in-plane equilibrium derived in this thesis, the elastic response of fixed arches at elevated temperatures and the attainment of first yield are examined in detail. The arch deflects transversely without bound in the elastic range at elevated temperatures, whereas it will yield first at the top extreme fibre of the cross section at the supports when a critical temperature is reached. The influence of several parameters such as the included angle is also considered. Based on the models of stress distributions at cross sections, the spread of yield both through the cross section and along the length of the arch is studied. It is indicated that the progress of yielding causes the first two hinges to form at the supports of the fixed arches, and then moment redistribution leads to the generation of the third hinge at the crown with an increase of temperature. Thus nonlinear plastic hinge analysis can be applied to the arch analysis under thermal loading.

The current research work investigates the behaviour of steel and composite beams as well as beam-to-column connections at elevated temperatures. Significant attention is needed to identify the main issues, as the behaviour is profoundly different from that at ambient temperature. Local buckling of the beam flange outstands has been found to be highly significant in accelerating the development of catenary action in fire, since this action is reliant on hinges forming which may result from local buckling. Local buckling of the beam web, which experiences a non-uniform temperature variation, is also important because the mechanical properties of the steel are degraded non-uniformly from their ambient values. Current formulations for web buckling at ambient temperature therefore need substantial revision at elevated temperatures. Very large compressive forces are developed within the beams initially and these induce large stresses in the column web; hitherto this has not been considered. Developing a formulation representing the mechanics of this potential failure zone in the column web in the compression region of the connection is a useful and needed addition to research in the topic. Predicting the critical temperature in a connection that causes failure of the bolts, end plate and column flange in the tension zone of the connection is considered in this research work. An elastic analysis of a panel zone in a rigid or semi-rigid joint in a steel frame, which is based on simple equilibrium considerations that takes into account the shear and flexural deformations of the panel zone, is developed at elevated temperatures. In order to model the structural response of a composite beam restrained by cooler members in a steel compartment fire in a frame structure at elevated temperature, recourse is needed to a geometric nonlinear formulation, since the beam transverse deflections are not negligible and the axial compressive force in the member is also substantial at the early stages of the fire. This thesis presents such a formulation, which incorporates partial interaction between the concrete slab and steel component, as well as the degradation of the stiffnesses of the components of the composite beam prior to yield at elevated temperature.

Metals in industrial settings such as power plants are often subjected to high temperature and pressure aqueous environments, where failure to control corrosion compromises worker and environment safety. For instance, zircaloy (1.2-1.7 wt.% Sn) fuel rods are exposed to aqueous 250-310 oC coolant in CANDU reactors. The Pourbaix (EH-pH) diagram is a plot of electrochemical potential versus pH, which shows the domains of various metal species and by inference, corrosion susceptibility. Elevated temperature data for tin +II and tin +IV species were obtained using solid-aqueous phase equilibria with the respective oxides, in a batch vessel with in-situ pH measurement. Solubilities, determined via spectroscopic techniques, were used to calculate equilibrium constants and the Gibbs energies of Sn complexes for E-pH diagram construction. The SnOH3+ and Sn(OH) species were incorporated, for the first time, into the 298.15 K and 358.15 K diagrams, with novel G ͦ values determined at 358.15 K. / UOIT

The fatigue response of mechanical properties and life due to constant stress amplitude tension-tension(T-T)cyclic loading at elevated temperature in nanocomposite APC-2 laminates was investigated. From the basic testing the total amount of 1% by weight of SiO2 spreaded in the interfaces was proved optimally. Related experiments on unidirectional nanocomposite APC-2 laminates were completed, including static tension tests in [0]16¡B[30]16¡B[45]16¡B[60]16 and [90]16 and T-T cyclic tests in [0]16¡B[45]16 and [90]16 specimens at room temperature. After obtaining experimental data, such as ultimate strength and elastic modulus, which were found improved significantly, and then comparing with the basic theory of mechanics of composites, rule of mixtures was adopted to estimate the properties of cross-ply and quasi-isotropic nanocomposite APC-2 laminates and found the largest errors were within 25%. In the consideration of heterogeneous and anisotropic properties of the matrix and the reinforced fibers in nature, the results are reasonably acceptable. On the other hand, the S-N curves according to the experimental data of the fatigue tests were plotted. The vertical axis shows the nondimensional stress level, i.e., the applied maximum stress normalized by ultimate strength at room temperature, and the horizontal axis represents the logarithm of applied cycles. The S-N curves at room and elevated temperatures were also expressed by curve fitting from top to bottom as temperature increasing from RT to 150¢J for both cross-ply and quasi-isotropic nanocomposite laminates. However, when applied maximum stress was normalized by the corresponding ultimate strength, the positions of S-N curves were reverse, i.e., the curves were shown from bottom to top as temperature increasing from RT to 150¢J. That strongly hints us the resistance to fatigue at elevated temperature in both lay-ups of nanocomposite laminates is indeed significantly improved.

Because magnesium alloy tube has good formability at elevated temperature, uniaxial tensile tests were employed to evaluate the warm properties of AZ31 magnesium alloy. After that, this paper has designed and manufactured a hydraulic bulge warm forming machine which can be used to experiment with fixed tube length. Using this testing machine, the experiments of hydraulic bulge forming of AZ31 magnesium alloy and 6061 aluminum alloy tube at elevated temperatures were carried out. According to experimental results, the hydraulic bulge forming properties of tubes at different temperatures are discussed.