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Cross-linked polymers of phenylacetylene and 1,3-diethynylbenzene: new polymer precursors for nanoporous carbon materials for supercapacitors and gas storage
Get PDFThe increasing threats of global warming, rapid depletion of fossil fuels, and
increasing energy demands are driving an enormous amount of research into clean
renewable sources of energy, flue gas capture technologies, and environmentally friendly
energy storage devices, to name a few. Activated carbons present a multipurpose
material commonly used in many of these increasingly popular green technologies.
A wide range of cross-linked acetylenic polymers of phenylacetylene and 1,3-
diethynylbenzene were synthesized and investigated in this thesis to generate materials
for electrochemical double layer capacitors, CO2 capture, and hydrogen storage.
Chemical activation of the copolymers in the presence of KOH was shown to produce
highly microporous carbons with various textural properties. The specific cross-linking
densities of the polymer precursors prior to carbonization were shown to greatly affect the
carbon yield, surface area, pore volumes and pore sizes of the carbons produced.
Electrochemical measurements of the activated carbons showed their impressive
performances as capacitor materials, with high specific capacitances (up to 446 F g−1 at
0.5 A g−1 in 3-electrode cell) and long cycle life. Gas sorption studies also demonstrated
impressive H2 and CO2 adsorption capacities (up to 2.66 wt% or 13.3 mmol g−1 for H2
adsorption at 77 K and 1 atm, and up to 30.6 wt% or 6.95 mmol g−1 for CO2 adsorption at
273 K and 1 atm).
Owing to the high content of pendent alkyne groups in these polymers,
complexation reactions with metallic carbonyl ligands are able to provide an effective
iv
way of dispersing metallic and metal oxide nanoparticles within the synthesized
copolymers, which could provide additional pseudocapacitive properties. An appropriate
copolymer with high alkyne content was subjected to complexation with Co2(CO)8, and
subsequently carbonized and oxidized to yield carbon-supported CoxOy/Co nanoparticles
(CoxOy@C-CPD76%). In addition to pseudocapacitive contributions, the cobalt species
also effectively catalyzed the production of graphitic networks within the carbon support,
improving their conductive properties. Electrochemical measurements demonstrated
impressive specific capacitance (310 F g−1 at 0.1 A g−1) compared with non-activated
carbons (160 – 177 F g−1 at 0.1 A g−1) synthesized at identical conditions, and provided a
large stable potential window (1.4 V) in an aqueous KOH solution. The combined
electrochemical double layer capacitance and pseudocapactiance behaviour of the carbon
and CoxOy/Co also provided improved energy densities (21 W h kg−1), and
uncompromised power densities (2017 W kg−1) compared with the pristine carbons
(~2034 W kg−1)
Introduction to special section: Mining and minerals exploration interpretation
No full textMineral deposits are found in a variety of geologic settings and ore-forming minerals can have a vast range of physical properties. The search for these deposits is also relatively near-surface thus far. These factors allow for a large number of possible airborne and ground-based techniques to be used in geophysical exploration. Deciding on the proper geophysical technique and survey layout requires an understanding of the target, its associated alteration, the variations in physical properties and the geologic and structural setting. Knowing the exploration history is important, particularly in exploration programs that are more mature. Interpretation of the data requires the integration of the myriad of information ranging from physical property models constructed from inversions or forward modeling, physical property data, geochemical data, mineral deposit model, and host geology.
We envisioned a special section on mining geophysics to highlight the integrative nature of mining geophysics through a collection of papers using multiple geophysical data to provide geology and exploration rationale along with the interpretations. So in collaboration with the editor of Interpretation, we issued a call for papers that discussed geophysics as applied to mining, discussed all relevant geophysical data and provided geologic information and the exploration rationale along with the interpretations. The following papers provide insight into the importance of geophysics in mineral exploration from the belt or camp scale to exploration focused on a specific orebody.
Wright and Koehler combine controlled-source audio magnetotelluric and gravity data in a previously explored terrain of the Carlin trend. The authors demonstrate that successive geophysical surveys, combined with geologic understanding and target model development were key to a significant gold discovery.
Martinez and Li demonstrate that lithological interpretation techniques based on inversion of airborne gravity gradiometry and aeromagnetic data can be used to characterize an iron-ore formation in Minas Gerais. The authors show that lithology differentiation using either generic physical property constraints or geologic constraints can contribute to a geologic understanding at the deposit scale.
Olaniyan et al. study the 3D geologic and structural setting of the Sudbury structure using an integration of geologic data with airborne gravity and magnetic data. Using standard 2.5D modeling and 3D Geomodeller software, they generate continuous surfaces in three dimensions for each geologic interface, which leads them to suggest a possible deformation history of the Sudbury structure.
Woolrych et al. present data from a range of airborne and ground-based geophysical techniques that have contributed to the discovery of the Kitumba iron oxide copper gold (IOCG) deposit in central Zambia. The interpretation of geophysical data following an exploration criteria of an IOCG-type deposit model has opened up exploration for this style of deposit in Central Zambia.
Lü et al. present a case study that demonstrates the use of integrating seismic, magnetotelluric, gravity, and magnetic data to interpret the 3D structure and deformation at depth in the Lu-Zong ore district of Eastern China. Insights were obtained into the fault systems and crustal architecture that are essential for understanding the Lu-Zong ore district mineral system and for mineral exploration at depth.
Legault et al. present the results of three different airborne electromagnetic (EM) surveys over the Lalor copper-zinc-gold volcanogenic massive sulfide deposit, which is more than 500 m deep and is in the Flin Flon Greenstone Belt of north-central Manitoba. The active and passive source EM surveys span a five year period, which means that the development of EM systems over this period can be assessed
Trajectoire géographique et occupation de l’espace urbain du grand Sudbury par les immigrants francophones
No full textDepuis quelques années l’immigration francophone dans le Grand Sudbury est en constante augmentation. Cette immigration suit une logique d’intégration dont les aspects sociologiques, économiques et culturels ont été beaucoup étudiés. Toutefois, l’étude de la dimension spatiale qui caractérise ce processus migratoire reste embryonnaire. La trajectoire géographique et le processus d’occupation de l’espace définis par les immigrants constituent un outil primordial d’analyse de leur intégration et de leur impact spatial sur la configuration territoriale de la ville du Grand Sudbury. Dès lors, l’objectif de la présente étude est de comprendre si la trajectoire géographique et l’occupation de l’espace actuel aboutissent à la mise en place d’une hétérogénéité spatiale ou à une homogénéité spatiale ? En d’autres termes, la trajectoire et l’occupation spatiale des immigrants francophones permettent-elles d’envisager un processus d’agrégation spatiale ou de désagrégation spatiale? Suite à une enquête terrain, l’étude montre que l’occupation de l’espace par les immigrants francophones n’aboutit pas nécessairement à une ségrégation spatiale ou du moins à une ghettoïsation de l’espace urbain à Sudbury
Cultural differences in perception of desirability of parental style: the role of sex and age of the child
No full textThe present study investigated the perceptions of emerging adults regarding desirable parental styles and sought to gain an understanding of whether cultural background, the age paradigm of the child being reared, and gender (of the respondent and child) were contributing factors. A modified version of the Parental Styles Questionnaire was used to measure the perceptions of desirable parental practices. The current study demonstrated that the democratic style of parenting was perceived as the favoured parental practice by both Chinese and Canadian respondents, that the permissive style of parenting was perceived negatively by both cultures (significantly more so by Canadians), and that authoritarian practices were perceived negatively by Chinese, while they were perceived positively by Canadian (when parenting both genders and significantly more so for boys). There were no significant differences in perceptions according to the age of the child or gender of the respondent
Exploring the impact of kindergarten scheduling on children's physical activity and classroom behaviour.
No full textThe Ontario Ministry of Education implemented the new Early Learning Kindergarten (ELK) program province-wide in September 2014. The ELK program advocates for inquiry- and play-based learning, and the use of the outdoors. Some school boards have implemented a 60-minute outdoor exploration block replacing outdoor recess breaks. These changes have not been
evaluated for their potential impact on both the physical activity levels and classroom behaviour of children while at school. This thesis investigated physical activity levels and classroom behaviour of children in the new ELK schedule, and in the Balanced School Day (BSD) schedule. The results suggest that children following the ELK program exhibit reduced physical activity levels, but greater academic engagement and less disruptive behaviour. Thus, results suggest that the ELK program provides benefits for students, but modifications are needed to
ensure that adequate physical activity is introduced in early-year programming therefore providing a strong foundation for both education and physical activity
Combining spatial components and Hilbert transforms to interpret ground-time-domain-electromagnetic data
No full textThis paper is © 2019 Society of Exploration Geophysicists. The posting is available free of charge and its use is subject to the SEG terms and conditions: https://seg.org/Terms-of-UseWe have developed a method for displaying or imaging data from a ground-time-domain electromagnetic system and for extracting the geometric parameters of a small conductor. The parameters are determined directly from the data using combinations of the spatial components of the secondary fields and their Hilbert transforms. The position of the target coincides with the peaks of the energy envelope (EE) or the -component of the response. Here, the EE is the square root of the sum of the squares of the three spatial components and their Hilbert transforms, whereas the -component response is an analogous quantity that excludes the Hilbert transform terms. Studies on synthetic models indicate that the -component response is sharper than the EE in most possible target orientations. Once the position of a body has been determined using the peak of the -component response, the dip of the target can be quantified using the ratio of the full-width at half-magnitude (FWHM) of the -component response and the -component Hilbert transform response, which is analogous to the EE but excludes the untransformed quantities. Finally, once all other geometric parameters have been determined, the depth of the target can be evaluated using the FWHM of the -component response. The proposed modeling method was tested over an anomaly acquired at the Coulon field site during an InfiniTEM survey in the Abitibi greenstone belt of Quebec. The extracted geometric parameters were consistent with the available geologic information
A multiple transmitter and receiver electromagnetic system for improved target detection
No full textThis paper is © 2019 Society of Exploration Geophysicists. The posting is available free of charge and its use is subject to the SEG terms and conditions: https://seg.org/Terms-of-UseWe have developed an alternative strategy for the inevitable deeper inductive electromagnetic (EM) exploration, which will be required as shallow deposits are exhausted. Rather than using very large magnetic moment ground loops, measurement stations are repeated using many smaller sized loops with smaller moments. The multiple transmitter data are then weighted and summed into a single high signal-to-noise ratio (S/N) composite transmitter. The composite transmitter can be thought of as a postprocessing method that uses the collected multitransmitter data to construct/simulate a transmitter, which maximizes the coupling to a particular target. The appropriate transmitter weights to use will depend on the target location and geometry, and, as such, different weighting schemes allow for the construction of different composite transmitters, each of which will maximally highlight different targets. We have assumed no prior knowledge of the location and orientation of the exploration targets, and we constructed composite transmitters for each possible location of a discretized subsurface and 324 possible target orientations (dipole embedded within a fully resistive medium). A modified difference of squares and a dipole look-up table was used to assess the fit between each composite transmitter and the suggested target location and orientation. Synthetic studies using conductive plate target(s) embedded within a fully resistive medium found that the target locations and orientations could be accurately determined and that the S/N of the composite transmitter was significantly higher than that of standard fixed-loop ground and airborne surveys. In a ground time-domain EM field test, 23 transmitter positions were used, and a shallow target (conductive dike) could be identified using the developed methodology. The composite transmitter data we produced was considerably easier to interpret and had a larger amplitude than that of any one single transmitter.NSERC, Vale, Sudbury Integrated Nickel Operations, a Glencore Company, Wallbridge Mining, KGHM International, and the Centre for Excellence in Mining Innovation
A pedagogical analysis of critical thinking deployed by health and physical education teachers at the secondary school level
Get PDFBackground: Several pedagogical research studies acknowledge instruction in Health and Physical Education as being conducive to the development of critical thinking skills in students. However, little empirical research has focused on the presence of this form of thinking in Health and Physical Education (HPE) teachers. Yet according to various researchers in the field of pedagogy, the presence of critical thinking skills in the teacher is crucial to promote its development in students during the teaching-learning process. Objective: The present study is a follow-up of previous research examining the manifestations of critical thinking in teachers at the primary school level and is intended to identify expressions of critical thinking and define its role in the professional conduct of three Health and Physical Education (HPE) teachers (two men and one woman) at the secondary school level. Methodology: The theoretical framework for this study is based on the concept of critical thinking developed by Matthew Lipman. The procedure used in this study involved video recording nine health and physical education lessons delivered by the three teachers followed by nine semi-structured interviews with the teachers using the technique of stimulated recall. Result and discussion: The results indicated not only the presence of critical thinking in the teachers, but also that this form of
thinking has multiple facets of expression. In terms of its function, critical thinking is essentially utilized as a genuine tool for teachers to evaluate the pertinence or viability of their instructional approach with students at the secondaryschool level
The design and evaluation of Novel prototypes to visualize web browsing history
Get PDFMainstream Web browsers support users in revisiting Web Pages by providing them with a history tool. Research shows that this history tool is severely underutilized. One possible reason is the manner in which the pages are displayed: a linear list of textual links. This thesis investigates the redesign of the history tool by introducing visualization to display the visited Web pages. Three distinct visual prototypes were designed ranging from a traditional scientific visualization method to a concrete visualization that incorporates a metaphor and knowledge transfer from the real-world. The low-fidelity prototypes were evaluated by participants and the best performing design was implemented as a high-fidelity prototype. Further evaluation with participants was conducted and the results were compared against the performance of participants using the traditional history tool of linear textual links
