We studied the migration of nonmagnetic, submicrometer polystyrene beads submerged in a magnetic fluid in the presence of nonuniform magnetic fields as a potential method for size-based separation of submicrometer, nonmagnetic species. Since the polystyrene beads are much larger than the magnetic fluid nanoparticles, the magnetic fluid was treated as a one-component continuum with respect to the beads. We found that the polystyrene beads will migrate in the direction of decreasing magnetic fields and will focus over a region where the magnetic field or its gradient vanishes, as predicted by our model. The concentration profiles predicted by our model, which has no adjustable or fitted parameters, agree reasonably well with the experimental data both qualitatively and quantitatively. / Singapore-MIT Alliance (SMA)

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Prior research suggests that the use of accounting information differs substantially by investor class. My analysis extends this line of research to the area of SEC Form 8-K filings. Prior research also provides mixed evidence on the informativeness of these filings. I hypothesize that the method of the disclosure is an important factor in evaluating 8-K usefulness to varying types of investors. Specifically, the timing, venue, and packaging of these accounting disclosures affect their use by investors. Regulation Fair Disclosure (2000) considers both press releases and 8-K filings as broad-based disclosures that do not favor any investor class. I, however, identify five unique informational settings in which 8-K filings occur. The five settings are: a concurrent 8-K event and filing (with or without a press release), a filing which precedes the press release, a press release that precedes the filing, an 8-K event that precedes a filing and/or press release, and the 8-K event alone. I examine the similarities and differences in trading by small and large investors across these settings. The identification of these empirical regularities with respect to disclosure form should be particularly useful to policy makers seeking to implement level playing field objectives with respect to public disclosures. My findings show that the relative trading activity to 8-K filings is different by the type of disclosure. Differential trading activity was found to be more pronounced in disclosure settings that contained a public announcement. In addition, the type of Form 8-K disclosure also had an effect on the differential trading activity. Form 8-K filings of acquisition or disposition of assets were associated with the most pronounced responses. My findings show the differential trading activity to these filings differs from other accounting events such as earnings announcements and annual report filings.

The purpose of this study is to get an understanding of how teachers in electricity and electronics use teamwork in school. The study was carried out in two upper secondary schools in the middle of Sweden. The method I use is qualitative interviews. The analysis method I selected is an ad hoc method. Teachers regard the use of teamwork in school today as valuable because society and several occupations today demand co-operation and teamwork. Teachers see the advantages when pupils can exchange ideas with each other and get other opinions. Other aspects to why teachers choose teamwork in school is that poor pupils can get support from others. A problem teachers discover is that good students can be prevented to move forward at a higher pace as result of the teamwork. The importance of group size for teamwork and other positive effects due to the presence of others is also discussed. / Syftet med undersökningen är få en insikt i hur ellärare på gymnasiet jobbar med grupparbete i skolan. Metoden som undersökningen bygger på är kvalitativa intervjuer som gjordes på två olika gymnasieskolor i Mellansverige. Valet av analys metod blev den vanliga ad hoc. Resultatet visar att lärarna ser vikten av grupparbeten och samarbetsträning i skolan idag beroende på att det krävs samarbete inom flera yrkesområden och verksamhetsfält ute i samhället. Lärarna ser också behovet att elever får byta idéer och får andra elevers åsikter i undervisningen. Andra aspekter som lärarna tar upp är att svaga elever får stöttning i grupparbetet, men också att starka elever ibland ser grupparbetet som ett hinder för att gå snabbare fram. Gruppstorlekens betydelse för grupparbetet och de positiva effekter som kan uppstå vid enbart social närvaro mellan personer belyses.

Innovation and commercialization are crucial for the competitiveness and economic well-being of countries. Despite the importance of innovation, recent studies have showed that Canada is lagging behind other countries in terms of its innovation and commercialization performance. The claim is often made that Canada performs well in generating the knowledge needed for innovation; however, the problem lies in transforming this knowledge into commercial success. Thus, a major preoccupation is how to turnaround this weak commercialization performance. Despite the wide range of programs, policies and regulations implemented by the Canadian Government along with its provincial counterparts to engender a turnaround, little has changed in Canada’s commercialization performance. Therefore, the search for solutions continues. Given that commercialization takes place at the firm-level, this study will explore the relationship between firm-size and commercialization. Several existing studies have examined the link between innovation and firm size, but few have examined the link between commercialization and firm size. Despite the arguments supporting medium-sized firms’ ability to commercialize innovations, there is a weak empirical base that explores the position of Canadian medium-sized firms and their innovation and commercialization capabilities. This study will contribute to the existing knowledge by covering the gap in the literature concerning the role of medium-sized firms in commercialization, compared to small and large firms. This study provides evidence suggesting that small and medium-sized firms should be considered differently.

Vertebrate brain size is remarkably variable at all taxonomic levels. Brains of mammals forexample, range from 0.1 gram in small bats (Chiroptera) to about 8-9 kilos in Sperm whales(Physeter macrocephalus). But what does this variation in size really mean? The link between brainsize and cognition is debated due to, for instance the difficulties of comparing cognitive ability indifferent species. A large number of comparative studies continue to provide information aboutcorrelations found both within and between species. The relative size of the brain is an example of apopular measurement that correlates with cognitive ability. But to date, no experimental studieshave yielded any proof causality between relative brain size and cognitive ability. Here I usedguppies selected for either large or small relative brain size to investigate differences in cognitiveperformance of a quantity discrimination task. The results from this experiment provideexperimental evidence that relative brain size is important for cognitive ability, and that a differencein cognitive ability could be obtained already after two generations of selection experiments onrelative brain size in a vertebrate. / Artificial Selection on Relative Brain Size in the Guppy Reveals Costs and benefits of Evolving a Larger Brain

<p>In this thesis, a study of the rational design and fabrication of microfluidic systems for microsphere generation is presented. The required function of microfluidic systems is to produce microspheres with the following attributes: (i) the microsphere size being around one micron or less, (ii) the size uniformity (in particular coefficient of variation (CV)) being less than 5%, and (iii) the size range being adjustable as widely as possible.</p> <p>Micro-electro-mechanical system (MEMS) technology, largely referring to various micro-fabrication techniques in the context of this thesis, has been applied for decades to develop microfluidic systems that can fulfill the foregoing required function of microsphere generation; however, this goal has yet to be achieved. To change this situation was a motivation of the study presented in this thesis.</p> <p>The philosophy behind this study stands on combining an effective design theory and methodology called Axiomatic Design Theory (ADT) with advanced micro-fabrication techniques for the microfluidic systems development. Both theoretical developments and experimental validations were carried out in this study. Consequently, the study has led to the following conclusions: (i) Existing micro-fluidic systems are coupled designs according to ADT, which is responsible for a limited achievement of the required function; (ii) Existing micro-fabrication techniques, especially for pattern transfer, have difficulty in producing a typical feature of micro-fluidic systems - that is, a large overall size (~ mm) of the device but a small channel size (~nm); and (iii) Contemporary micro-fabrication techniques to the silicon-based microfluidic system may have reached a size limit for microspheres, i.e., ~1 micron.</p> <p>Through this study, the following contributions to the field of the microfluidic system technology have been made: (i) Producing three rational designs of microfluidic systems, device 1 (perforated silicon membrane), device 2 (integration of hydrodynamic flow focusing and crossflow principles), and device 3 (liquid chopper using a piezoelectric actuator), with each having a distinct advantage over the others and together having achieved the requirements, size uniformity (CV ⤠5%) and size controllability (1-186 &#x00B5;m); (ii) Proposing a new pattern transfer technique which combines a photolithography process with a direct writing lithography process (e.g., focused ion beam process); (iii) Proposing a decoupled design principle for micro-fluidic systems, which is effective in improving microfluidic systems for microsphere generation and is likely applicable to microfluidic systems for other applications; and (iv) Developing the mathematical models for the foregoing three devices, which can be used to further optimize the design and the microsphere generation process.</p>

This thesis is based on observations of the physical properties of wheat flour dough using ultrasonic measurements. Three frequency ranges were used in the study, low frequencies (near 40 kHz), intermediate frequencies (1 to 5 MHz, where bubble resonance effects are apparent), and high frequencies (near 20 MHz). Doughs mixed under different head space air pressures, from vacuum to atmospheric pressure, as well as under nitrogen, were studied at low frequency to investigate their relaxation behavior. Subsamples from ambient dough and vacuum dough displayed differences in the dependence of velocity and attenuation on time after compression, but no post mixing relaxation effect was apparent. A critical headspace pressure of approximately 0.16 atmospheres determined whether vacuum-like or ambient-like relaxation was observed. A peak in attenuation and changes in ultrasonic velocity were observed around the bubble resonance frequency, and these ultrasonic parameters changed substantially as a function of time. A bubble resonance model was used to interpret the results around the bubble resonance frequency, and bubble size distributions were estimated for ambient and vacuum dough from the ultrasonic data. For the high frequency range, a molecular relaxation model was used to interpret the results. Different fast relaxation times were observed for ambient dough (5 ns) and vacuum dough (1 ns). This relaxation time may be associated with conformational rearrangements in glutenin inside the dough matrix. These experiments have enabled dough relaxation to be probed over a very wide range of time scales (from ns to hours), and will lead to a better understanding of the role of dough matrix and gas cell effects on the physical properties of wheat flour doughs. / October 2007

Innovation and commercialization are crucial for the competitiveness and economic well-being of countries. Despite the importance of innovation, recent studies have showed that Canada is lagging behind other countries in terms of its innovation and commercialization performance. The claim is often made that Canada performs well in generating the knowledge needed for innovation; however, the problem lies in transforming this knowledge into commercial success. Thus, a major preoccupation is how to turnaround this weak commercialization performance. Despite the wide range of programs, policies and regulations implemented by the Canadian Government along with its provincial counterparts to engender a turnaround, little has changed in Canada’s commercialization performance. Therefore, the search for solutions continues. Given that commercialization takes place at the firm-level, this study will explore the relationship between firm-size and commercialization. Several existing studies have examined the link between innovation and firm size, but few have examined the link between commercialization and firm size. Despite the arguments supporting medium-sized firms’ ability to commercialize innovations, there is a weak empirical base that explores the position of Canadian medium-sized firms and their innovation and commercialization capabilities. This study will contribute to the existing knowledge by covering the gap in the literature concerning the role of medium-sized firms in commercialization, compared to small and large firms. This study provides evidence suggesting that small and medium-sized firms should be considered differently.

<p>In this thesis, a study of the rational design and fabrication of microfluidic systems for microsphere generation is presented. The required function of microfluidic systems is to produce microspheres with the following attributes: (i) the microsphere size being around one micron or less, (ii) the size uniformity (in particular coefficient of variation (CV)) being less than 5%, and (iii) the size range being adjustable as widely as possible.</p> <p>Micro-electro-mechanical system (MEMS) technology, largely referring to various micro-fabrication techniques in the context of this thesis, has been applied for decades to develop microfluidic systems that can fulfill the foregoing required function of microsphere generation; however, this goal has yet to be achieved. To change this situation was a motivation of the study presented in this thesis.</p> <p>The philosophy behind this study stands on combining an effective design theory and methodology called Axiomatic Design Theory (ADT) with advanced micro-fabrication techniques for the microfluidic systems development. Both theoretical developments and experimental validations were carried out in this study. Consequently, the study has led to the following conclusions: (i) Existing micro-fluidic systems are coupled designs according to ADT, which is responsible for a limited achievement of the required function; (ii) Existing micro-fabrication techniques, especially for pattern transfer, have difficulty in producing a typical feature of micro-fluidic systems - that is, a large overall size (~ mm) of the device but a small channel size (~nm); and (iii) Contemporary micro-fabrication techniques to the silicon-based microfluidic system may have reached a size limit for microspheres, i.e., ~1 micron.</p> <p>Through this study, the following contributions to the field of the microfluidic system technology have been made: (i) Producing three rational designs of microfluidic systems, device 1 (perforated silicon membrane), device 2 (integration of hydrodynamic flow focusing and crossflow principles), and device 3 (liquid chopper using a piezoelectric actuator), with each having a distinct advantage over the others and together having achieved the requirements, size uniformity (CV ⤠5%) and size controllability (1-186 &#x00B5;m); (ii) Proposing a new pattern transfer technique which combines a photolithography process with a direct writing lithography process (e.g., focused ion beam process); (iii) Proposing a decoupled design principle for micro-fluidic systems, which is effective in improving microfluidic systems for microsphere generation and is likely applicable to microfluidic systems for other applications; and (iv) Developing the mathematical models for the foregoing three devices, which can be used to further optimize the design and the microsphere generation process.</p>