Microscale Chemistry

The focus of the thesis is on the evaluation of the effect of the implementation of a three-hour per week problem-based learning (PBL) module for 1st year undergraduate students. The research questions are outlined below:
• What approaches to learning are undergraduate students adopting at the initial stage of tertiary education?
• Are student approaches to learning related to age/gender/ time in university/achievement in examinations?
• Can a PBL module in chemistry be developed that can provide an effective teaching and learning environment, which develops students’ understanding in chemistry and engages the students with the context and processes of chemistry?
• Will the introduction of such a PBL module in chemistry have an effect on students’ approaches to learning?
The main evaluation tool for determining student approaches to learning was the learning style inventory – Approaches and Study Skills Inventory for Students. Other evaluation tools employed were student surveys, interviews and assessment data.

Key findings were that students on entry to tertiary level report a preference for deep and strategic approaches to learning over a surface approach. However, with time in university, the profile shifts with students indicating increasing use of a surface approach. Mature students tended to prefer a deep approach in comparison to their younger counterparts and female students were more strategic than males in their approach.

An introductory year-long chemistry PBL laboratory module was developed, implemented and evaluated. Interestingly, students who took part in the PBL module showed a lower preference for a surface approach having successfully completed the PBL module compared to those who followed the traditional approach despite showing similar trends at the start of the study. The effect on a deep approach to learning, after taking the PBL module, one sixth of the 1st year course, was not evident however. Conversely, the PBL students did significantly better in a non-formal exam designed to assess students learning in the first year chemistry laboratory. The students also successfully engaged with the chemistry content, context and processes and reported the benefit of the pre-lab, group work and practical aspects of the PBL approach.

Scleractinian corals are a major source of biogenic calcium carbonate, yet the relationship between their skeletal microstructure and mechanical properties has been scarcely studied. In this work, the skeletons of two coral species: solitary Balanophyllia europaea and colonial Stylophora pistillata , were investigated by nanoindentation. The hardness H IT and Young's modulus E IT were determined from the analysis of several load–depth data on two perpendicular sections of the skeletons: longitudinal (parallel to the main growth axis) and transverse. Within the experimental and statistical uncertainty, the average values of the mechanical parameters are independent on the section's orientation. The hydration state of the skeletons did not affect the mechanical properties. The measured values, E IT in the 76–77 GPa range, and H IT in the 4.9–5.1 GPa range, are close to the ones expected for polycrystalline pure aragonite. Notably, a small difference in H IT is observed between...

Description. In 2005 we published an article in the Journal of Chemical Education describing a microscale ozone generator. 2 The generator is capable of producing 800 nanomole of ozone per minute. At this rate, it would take 18 days of continuous operation to generate one gram of ozone! Nevertheless, enough ozone is generated to detect the odor at a level similar to that produced by a photocopy machine or a Tesla coil. Despite the small amount of ozone generated, there is enough to cause a variety of interesting oxidations. In our original article, we described the oxidation of food coloring over the course of minutes. Here we greatly expand the list! In this article we describe an improvement in design using a framework built of elbow drinking straws on a base consisting of a 96-well plate — in the spirit of Professor Steve Thompson's (Colorado State University) microscale architecture. We also describe a wide variety of other oxidations of foods and other materials. Apparatus. The apparatus used is shown in Figure 1 and a photograph is provided at our website.

Precursory signals, manifestations of microscale damage that precedes dynamic faulting, are key to earthquake forecasting and risk mitigation. Detections of precursors have primarily relied on measurements performed using sensors installed at some distance away from the rupture area in-2-both field and laboratory experiments. Direct observations of continuous microscale damage accumulated during fault nucleation and propagation are scarce. Using an X-ray transparent triaxial deformation apparatus, we show the first quantitative high resolution three-dimensional (3D) information about damage evolution of rocks undergoing brittle failure. The dynamic microtomography images documented a spectrum of damage characteristics and different fault growth patterns. The interplay between various deformation mechanisms can result in either a positive, negative, or constant net volume change. Consequently, changes in rock density and acoustic wave velocities before faulting are expected to vary in different tectonics settings, hence making failure forecasting intrinsically dependent on rock type at depth.

Thin-film-based nanoporous membrane technologies exploit evaporation to efficiently cool microscale and nanoscale electronic devices. At these scales, when domain sizes become comparable to the mean free path in the vapour, traditional macroscopic approaches such as the Navier-Stokes-Fourier (NSF) equations become less accurate, and the use of higher-order moment methods is called for. Two higher-order moment equations are considered; the linearised versions of the Grad 13 and Regularised 13 equations. These are applied to the problem of nanoporous evaporation, and results are compared to the NSF method and the method of direct simulation Monte Carlo (i.e. solutions to the Boltzmann equations). Linear and non-linear versions of the boundary conditions are examined, with the latter providing improved results, at little additional computational expense, compared to the linear form. The outcome is a simultaneously accurate and computationally efficient method, which can provide simulat...

Ice-binding proteins (IBPs), including antifreeze proteins, ice structuring proteins, thermal hysteresis proteins, and ice recrystallization inhibition proteins, are found in cold-adapted organisms and protect them from freeze injuries by interacting with ice crystals. IBPs are found in a variety of organism, including fish 1 , plants 2, 3 , arthropods 4, 5 , fungi 6 , and bacteria 7