Quantitative estimation of plant characteristics using spectral measurement: A survey of the literature

There are no author-identified significant results in this report

Strain-induced kinetics of intergrain defects as the mechanism of slow dynamics in the nonlinear resonant response of humid sandstone bars

A closed-form description is proposed to explain nonlinear and slow dynamics effects exhibited by sandstone bars in longitudinal resonance experiments. Along with the fast subsystem of longitudinal nonlinear displacements we examine the strain-dependent slow subsystem of broken intergrain and interlamina cohesive bonds. We show that even the simplest but phenomenologically correct modelling of their mutual feedback elucidates the main experimental findings typical for forced longitudinal oscillations of sandstone bars, namely, (i) hysteretic behavior of a resonance curve on both its up- and down-slopes, (ii) linear softening of resonant frequency with increase of driving level, and (iii) gradual recovery (increase) of resonant frequency at low dynamical strains after the sample was conditioned by high strains. In order to reproduce the highly nonlinear elastic features of sandstone grained structure a realistic non-perturbative form of strain potential energy was adopted. In our theory slow dynamics associated with the experimentally observed memory of peak strain history is attributed to strain-induced kinetic changes in concentration of ruptured inter-grain and inter-lamina cohesive bonds causing a net hysteretic effect on the elastic Young's modulus. Finally, we explain how enhancement of hysteretic phenomena originates from an increase in equilibrium concentration of ruptured cohesive bonds that are due to water saturation.Comment: 5 pages, 3 figure

Development and application of a sensitive, high precision weighing lysimeter for use in greenhouses

A high precision weighing lysimeter for measuring evapotranspiration in greenhouses was developed. The instrument has a measurement of sensitivity of one part in 106, that is one order of magnitude better than any other so far described in the literature. With it, evaporation rates in a greenhouse, even at night, can be measured on a one minute time scale. Development and construction of the instrument are described and measurements of the transpiration of a tomato crop in a greenhouse are used to demonstrate its capabilities

Engaging communities, experiential learning and a classroom in the real world

Conference Theme: New Approaches in Teaching and Learning at Tertiary LevelAs part of curriculum reform at The University of Hong Kong, one of the key aspects is the implementation of experiential learning. By taking students out of the classroom into the real world, the traditional construct of problem-based learning, in which each problem proceeds an expected answer, is reversed. Introducing students in undergraduate education to complex situations with uncertain outcomes leads to a shift in educational priorities, a deeper understanding of the nature of inquiry, and the attainment of a wide variety of tools for knowledge acquisition. This paper presents three distinct courses in the Faculty of Architecture, each of which implemented a different aspect of experiential learning. The first course introduced students to an urgent contemporary issue in the local community and allowed them to actively provoke positive change through design research and community engagement. In the second course, students participated in the design and physical renovation of a 300-year old bridge in China. The third course was a multi-disciplinary design studio based upon the rebuilding of a traditional Chinese village. All three courses engaged students in novel situations with ill-defined problems and allowed them to confront the complexities involved in the application of theoretical ideas to make actual impact in the real world. This paper presents the approach and methodologies of the three courses’ in their collaboration with local communities’ to raise their awareness, enable their participation, and improve their lives. It concludes with a reflection on the challenges of achieving and assessing the stated learning outcomes and several lessons for future iterations of this type of curricular approach.postprin

Modeling and simulation of phase-transitions in multicomponent aluminum alloy casting

The casting process of aluminum products involves the spatial distribution of alloying elements. It is essential that these elements are uniformly distributed in order to guarantee reliable and consistent products. This requires a good understanding of the main physical mechanisms that affect the solidification, in particular the thermodynamic description and its coupling to the transport processes of heat and mass that take place. The continuum modeling is reviewed and methods for handling the thermodynamics component of multi-element alloys are proposed. Savings in data-storage and computing costs on the order of 100 or more appear possible, when a combination of data-reduction and data-representation methods is used. To test the new approach a simplified model was proposed and shown to qualitatively capture the evolving solidification front

Translocation of structured polynucleotides through nanopores

We investigate theoretically the translocation of structured RNA/DNA molecules through narrow pores which allow single but not double strands to pass. The unzipping of basepaired regions within the molecules presents significant kinetic barriers for the translocation process. We show that this circumstance may be exploited to determine the full basepairing pattern of polynucleotides, including RNA pseudoknots. The crucial requirement is that the translocation dynamics (i.e., the length of the translocated molecular segment) needs to be recorded as a function of time with a spatial resolution of a few nucleotides. This could be achieved, for instance, by applying a mechanical driving force for translocation and recording force-extension curves (FEC's) with a device such as an atomic force microscope or optical tweezers. Our analysis suggests that with this added spatial resolution, nanopores could be transformed into a powerful experimental tool to study the folding of nucleic acids.Comment: 9 pages, 5 figure

Ons Europaplein : ontwerp voor een nieuw Europaplein in Renkum

Het Europaplein in Renkum ligt er triest bij. Er is veel achterstallig onderhoud en het plein wordt als veel te stenig ervaren. Op basis van een gedegen sociaal ruimtelijke analyse en in nauwe samenspraak met de gebruikers van het plein is een schetsontwerp gemaakt voor een nieuw Europaplein: interessant voor iedereen met fijne plekken om te zitten en te spelen met midden op het plein mogelijkheden voor verschillende activiteiten. Het ontwerp is zo opgebouwd dat een gefaseerde realisatie mogelijk is. Afhankelijk van beschikbare financiering kunnen verschillende opties al dan niet worden uitgevoerd. Het ontwerp hoeft niet in één keer uitgevoerd te worden. De aanleg kan gespreid gerealiseerd worden zonder dat de kwaliteit van de uiteindelijke beoogde verbeteringen in het geding komt