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1. Difference in the behavior of oxygen deficient defects in Ge-doped silica optical fiber preforms under ArF and KrF excimer laser irradiation

Resource Type:: Article
Creator:: Essid, Mourad, Brebner, J.L., Awazu, K., and Albert, Jacques
Abstract:: Photobleaching of optical absorption bands in the 5 eV region and the creation of others at higher and lower energy have been examined in the case of ArF (6.4 eV) and KrF (5 eV) excimer laserirradiation of 3GeO2:97SiO2glasses. We report a difference in the transformation process of the neutral oxygen monovacancy and also of the germanium lone pair center (GLPC) into electron trap centers associated with fourfold coordinated Ge ions and Ge-E′ centers when we use one or the other laser. Correlations between absorption bands and electron spin resonance signals were made after different steps of laser irradiation. It was found that the KrF laser generates twice as many Ge-E′ centers as the ArF laser for the same dose of energy delivered. The main reason for this difference is found to be the more efficient bleaching of the GLPC (5.14 eV) by the KrF laser compared to that by the ArF laser.
Date Created:: 1998-10-15

2. Simultaneous corona poling of multiple glass layers for enhanced effective second-order optical nonlinearities

Resource Type:: Article
Creator:: Blanchetiere, C., Jacob, S., Callender, C. L., Albert, Jacques, Yadav, Ksenia, and Smelser, Christopher W.
Abstract:: Silica-based thin-film multilayers are investigated as a means to enhance the effective second-order nonlinearity induced in silica glass structures by corona poling. Structures consisting of phosphorus-doped and undoped silica glass layers exhibit second harmonic generation (SHG) that is higher by an order of magnitude compared to the SHG in bulk silica glass poled under the same conditions. When the poled structure consists of two multilayered stacks separated in space, the stacks exhibit comparable poling-induced nonlinearities. This result suggests that the poling voltage is divided between the two stacks such that simultaneous poling of multiple regions within the sample is realized.
Date Created:: 2011-07-18

3. Si ion implantation-induced damage in fused silica probed by variable-energy positrons

Resource Type:: Article
Creator:: Simpson, P.J., Ilard, L.B., Brebner, J.L., Knights, A.P., and Albert, Jacques
Abstract:: Samples of synthetic fused silica have been implanted at room temperature with silicon ions of energy 1.5 MeV. Fluences ranged from 1011 to 1013 cm−2. Samples were probed using variable‐energy positron annihilation spectroscopy. The Doppler‐broadening S parameter corresponding to the implanted region decreased with increasing fluence and saturated at a fluence of 1013 cm−2. It is shown that the decrease in the S parameter is due to the suppression of positronium (Ps) which is formed in the preimplanted material, due to the competing process of implantation‐induced trapping of positrons. In order to satisfactorily model the positron data it was necessary to account for positron trapping due to defects created by both electronic and nuclear stopping of the implanted ions. Annealing of the 1013 cm−2 sample resulted in measurable recovery of the preimplanted S parameter spectrum at 350 °C and complete recovery to the preimplanted condition at 600 °C. Volume compaction was also observed afterimplantation. Upon annealing, the compaction was seen to decrease by 75%.
Date Created:: 1996-06-16

4. Photosensitivity in phosphorus-doped silica glass and optical waveguides

Resource Type:: Article
Creator:: Hibino, Y., Hattori, K., Johnson, D. C., Hill, K. O., Kitagawa, T., Albert, Jacques, Bilodeau, F., Malo, B., and Gujrathi, S.
Date Created:: 1994-12-01

5. 1 W tunable dual-wavelength emission from cascaded distributed feedback fiber lasers

Resource Type:: Article
Creator:: Zhu, X., Peyghambarian, N., Albert, Jacques, Li, L., Moloney, J. V., and Schülzgen, A.
Date Created:: 2008-02-15

6. A thin metal sheath lifts the EH to HE degeneracy in the cladding mode refractometric sensitivity of optical fiber sensors

Resource Type:: Article
Creator:: Albert, Jacques, Berini, P., Chen, Chengkun, Caucheteur, C., and Voisin, V.
Abstract:: The effective indices of the cladding modes of optical fibers depend on the refractive index of the medium surrounding the fiber. We show experimentally and theoretically that while cladding modes with similar effective indices normally have similar refractometric sensitivities, the addition of a 50 nm thick gold sheath enhances the sensitivity of some EH modes by more than one order of magnitude while nearly completely suppressing the sensitivity of neighbouring HE modes (by three orders of magnitude, down to insignificant levels). A differential sensitivity of ∼1000 nm/(refractive index unit) is experimentally reported between adjacent EH and HE grating resonances.
Date Created:: 2011-07-25

7. Comparison of one-photon and two-photon effects in the photosensitivity of germanium-doped silica optical fibers exposed to intense ArF excimer laser pulses

Resource Type:: Article
Creator:: Johnson, D. C., Malo, B., Hill, K. O., Thériault, S., Bilodeau, F., and Albert, Jacques
Date Created:: 1995-12-01

8. Bragg gratings fabricated in monomode photosensitive optical fiber by UV exposure through a phase mask

Resource Type:: Article
Creator:: Albert, Jacques, Bilodeau, F., Malo, B., Hill, K. O., and Johnson, D. C.
Abstract:: A photolithographic method is described for fabricating refractive index Bragg gratings in photosensitive optical fiber by using a special phase mask grating made of silica glass. A KrF excimer laser beam (249 nm) at normal incidence is modulated spatially by the phase mask grating. The diffracted light, which forms a periodic, high-contrast intensity pattern with half the phase mask grating pitch, photoimprints a refractive index modulation into the core of photosensitive fiber placed behind, in proximity, and parallel, to the mask; the phase mask grating striations are oriented normal to the fiber axis. This method of fabricating in-fiber Bragg gratings is flexible, simple to use, results in reduced mechanical sensitivity of the grating writing apparatus and is functional even with low spatial and temporal coherence laser sources.
Date Created:: 1993-12-01

9. Four-wave mixing in carbon nanotube-coated optical fiber gratings

Resource Type:: Article
Creator:: Shao, Li-Yang, Simard, Benoit, Albert, Jacques, Sun, Tingting, and Jakubinek, Michael B.
Abstract:: The observation of four-wave mixing (FWM) in single-walled carbon nanotubes (SWCNTs) deposited around a tilted fiber Bragg grating (TFBG) has been demonstrated. A thin, floating SWCNT film is manually wrapped around the outer cladding of the fiber and FWM occurs between two core-guided laser signals by TFBG-induced interaction of the core mode and cladding modes. The effective nonlinear coefficient is calculated to be 1.8 10 3W -1Km -1. The wavelength of generated idlers is tunable with a range of 7.8 nm.
Date Created:: 2012-02-13

10. Fabrication of electron beam generated, chirped, phase mask (1070 . 11 – 1070 . 66 nm) for fiber Bragg grating dispersion compensator

Resource Type:: Article
Creator:: Hill, K.O., Johnson, D.C., Mihailov, S.J., McClelland, A.W., Stryckman, D., Bilodeau, F., Albert, Jacques, Carr, D.W., Hugues, B.J., Tiberio, R.C., and Rooks, M.J.
Abstract:: We report on the fabrication of a chirped, phase mask that was used to create a fiber Bragg grating(FBG)device for the compensation of chromatic dispersion in longhaul optical transmission networks.Electron beamlithography was used to expose the grating onto a resist-coated quartz plate. After etching, this phase mask was used to holographically expose an index grating into the fiber core [K. O. Hill, F. Bilodeau, D. C. Johnson, and J. Albert, Appl. Phys. Lett.62, 1035 (1993)]. The linear increase in the grating period, “chirp,” is only 0.55 nm over the 10 cm grating. This is too small to be defined by computer aided design and a digital deflection system. Instead, the chirp was incorporated by repeatedly rescaling the analog electronics used for field size calibration. Special attention must be paid to minimize any field stitching and exposure artifacts. This was done by using overlapping fields in a “voting” method. As a result, each grating line is exposed by the accumulation of three overlapping exposures at 1/3 dose. This translates any abrupt stitching error into a small but uniform change in the line-to-space ratio of the grating. The phase mask was used with the double-exposure photoprinting technique [K. O. Hill, F. Bilodeau, B. Malo, T. Kitagawa, S. Thériault, D. C. Johnson, J. Albert, and K. Takiguchi, Opt. Lett. 19, 1314 (1994)]: a KrF excimer laser holographically imprints an apodized chirped Bragg grating in a hydrogen loaded SMF-28 optical fiber. Our experiments have demonstrated a spectral delay of −1311 ps/nm with a linearity of +/−10 ps over the 3 dB bandwidth of the resonant wavelength of the FBG. The reflectance, centered on 1550 nm, shows a side-lobe suppression of −25 dB. Fabrication processes and optical characterization will be discussed.
Date Created:: 1998-09-16

11. Formation and bleaching of strong ultraviolet absorption bands in germanium implanted synthetic fused silica

Resource Type:: Article
Creator:: Trudeau, Y. B., Brebner, J. L., Hill, K. O., Kajrys, G., Albert, Jacques, Johnson, D. C., and Malo, B.
Abstract:: Germanium ions have been implanted in fused silica using ion beams having energies of 3 and 5 MeV and doses ranging from 1×1012 to 5×1014 ions/cm2. For wavelengths shorter than 400 nm, the optical absorption increases strongly with two absorption bands appearing at 244 and 212 nm. The ion-induced optical absorption can be bleached almost completely by irradiation with 249 nm excimer laser light. Ion implantation also increases the refractive index of silica near the substrate surface. At 632.8 nm a refractive index increase of more than 10-2 has been measured. This decreases by 4×10-3 upon bleaching with 249 nm light.
Date Created:: 1992-12-01

12. Ion implantation-induced strong photosensitivity in high-purity fused silica: Correlation of index changes with VUV color centers

Resource Type:: Article
Creator:: Brebner, J. L., Albert, Jacques, Allard, L. B., and Verhaegen, M.
Abstract:: We have studied optical changes induced by ArF (6.4 eV/193 nm) excimer laser light illumination of high purity SiO2 implanted with Si2+ (5 MeV) at a fluence of 1015 ions/cm2. Optical absorption was measured from 3 eV (400 nm) to 8 eV (155 nm) and showed evidence of several well-defined absorption bands. A correlation in the bleaching behavior appears to exist between the so-called D band (located at 7.15 eV) and the well-known B2α band which is attributed to oxygen vacancies. Changes in the refractive index as a function of ArF illumination were measured and found to be in good quantitative agreement with a Kramers-Kronig analysis of the optical absorption data.
Date Created:: 1996-12-01

13. Potassium and silver ion-exchanged dual-core glass waveguides with gratings

Resource Type:: Article
Creator:: Leonelli, R., Albert, Jacques, Li, M. J., Najafi, S. I., Honkanen, S., and Wang, W. J.
Abstract:: A two-step double ion-exchange process is employed to produce dual-core waveguides in glass. First, potassium ion exchange is carried out at 400°C. Then, silver ion exchange is performed at 300°C. The fabricated waveguides have low losses, large single-mode regions, and more symmetrical profiles than single ion-exchanged waveguides. Etched gratings are also made in dual-core waveguides. Very high efficiencies are demonstrated in these waveguides.
Date Created:: 1991-12-01

14. Maskless writing of submicrometer gratings in fused silica by focused ion beam implantation and differential wet etching

Resource Type:: Article
Creator:: Brebner, J. L., Bilodeau, F., Hill, K. O., Malo, B., Albert, Jacques, Templeton, I. M., and Johnson, D. C.
Date Created:: 1993-12-01

15. Au-coated tilted fiber Bragg grating twist sensor based on surface plasmon resonance

Resource Type:: Article
Creator:: Zhou, Wenjun, Albert, Jacques, Zhang, Yang, and Shen, Changyu
Abstract:: A fiber twist sensor based on the surface plasmon resonance (SPR) effect of an Au-coated tilted fiber Bragg grating (TFBG) is proposed. The SPR response to the twist effect on an Au-coated TFBG (immersing in distilled water) is studied theoretically and experimentally. The results show that the transmission power around the wavelength of SPR changes with the twist angle. For the twist ranging from 0° to 180° in clockwise or anti-clockwise directions, the proposed sensor shows sensitivities of 0.037 dBm/° (S-polarized) and 0.039 dBm/° (P-polarized), which are almost 7.5 times higher than that of the current similar existing twist sensor.
Date Created:: 2014-01-01

16. Strong Bragg gratings in phosphate glass single mode fiber

Resource Type:: Article
Creator:: Temyanko, V. L., Honkanen, S., Schülzgen, A., Albert, Jacques, and Peyghambarian, N.
Date Created:: 2006-09-15

17. Field-assisted patterned dissolution of silver nanoparticles in phosphate glass

Resource Type:: Article
Creator:: Albert, Jacques and Andreyuk, Alexander
Abstract:: Phosphate glass samples doped with silver ions through a Na+-Ag+ ion-exchange process were treated in a hydrogen atmosphere at temperatures near 430 °C for durations ranging from 4 to 5 h. Such treatment causes metallic silver precipitation at the surface as well as nanoclustering of silver atoms under the surface under conditions very similar to those used for silicate glasses. The presence of silver clusters resulted in a characteristic coloring of the glass and was verified by the observation of a plasmon resonance peak near 410-420 nm in the absorption spectra. Applying a DC voltage between 1.4 and 2 kV at temperatures between 120 and 130 °C led to dissolution of the clusters in the area under the positive electrode, thereby bleaching the glass color. The use of a patterned doped-silicon electrode further led to the formation of a 300 nm thick surface relief on the glass surface and of a volume complex permittivity grating extending at least 4 μm under the surface. Such volume complex refractive index gratings may find applications in passive or active (laser) photonic devices in rare-earth doped phosphate glasses, where conventional bulk grating formation techniques have limited applicability.
Date Created:: 2014-01-01

18. Analysis of Piezoelectric Ice Protection Systems Combined with Ice-Phobic Coatings

Resource Type:: Article
Creator:: Pommier-Budinger, Valerie, Tepylo, Nicolas, Budinger, Marc, and Huang, Xiao
Abstract:: The aeronautics industry is looking for ice protection systems consuming less energy. Electromechanical and especially piezoelectric solutions are a promising area of research for reducing average consumptions. This article provides an analytical model of a simple structure to assess the power and voltage required to obtain the delamination of the accumulated layer of ice at the support/ice interface. This model also allows analyzing the impact of the resonance frequencies used for supplying piezoelectric actuators on the tensile stress into PZT materials. Finally, this article assesses the effect of different ice - phobic coatings combined with piezoelectric ice protection systems. Experimental measurements of ice adhesion for different ice - phobic coatings allow evaluating the shear stress at which ice is detached from the surface. These results are then used to estimate - thanks to the proposed analytical model - the additional gain of power that would be provided by the use of such coatings.
Date Created:: 2016-06-10

19. Fabrication of a variable diffraction efficiency phase mask by multiple dose ion implantation

Resource Type:: Article
Creator:: Johnson, D. C., Champion, H. G., Erickson, L. E., Hill, K. O., Malo, B., Theriault, S., Bilodeau, F., and Albert, Jacques
Abstract:: A variable diffraction efficiency phase mask is produced by focused ion beam, implanting a grating pattern into a fused SiO 2 substrate with a 100-nm-diam, 200keV Si beam. The substrate is prepared by cleaning and coating with a 20-nm-thick film of Al to dissipate the ion charge. The pattern consists of 930 lines, each 80μm long, at a pitch of 1.075μm, to obtain a 1-mm-long grating. The substrate is wet etched in a 1M% HF solution for about 45min to produce a phase mask with the desired diffraction efficiency. This phase mask is used to photoimprint Bragg gratings into standard hydrogenated single-mode telecommunication fibers using 193nm light from an ArF laser.
Date Created:: 1995-11-01

20. Environmental controls of frost cracking revealed through in situ acoustic emission measurements in steep bedrock

Resource Type:: Article
Creator:: Girard, Lucas, Gruber, Stephan, Weber, Samuel, and Beutel, Jan
Abstract:: Frost cracking, the breakdown of rock by freezing, is one of the most important mechanical weathering processes acting on Earth's surface. Insights on the mechanisms driving frost cracking stem mainly from laboratory and theoretical studies. Transferring insights from such studies to natural conditions, involving jointed bedrock and heterogeneous thermal and hydrological properties, is a major challenge. We address this problem with simultaneous in situ measurements of acoustic emissions, used as proxy of rock damage, and rock temperature/moisture content. The 1 year data set acquired in an Alpine rock wall shows that (1) liquid water content has an important impact on freezing-induced rock damage, (2) sustained freezing can yield much stronger damage than repeated freeze-thaw cycling, and (3) that frost cracking occurs over the full range of temperatures measured extending from 0 down to -15°C. These new measurements yield a slightly different picture than previous field studies where ice segregation appears to play an important role. Key PointsRock liquid water content has an important impact on the freezing-induced damageSustained freezing can yield stronger damage than repeated freeze-thaw cyclingFrost cracking occurs on a wide range of temperatures extending from 0 to -15C
Date Created:: 2013-05-16

21. Low temperature plasma etching for Si3 N4 waveguide applications

Resource Type:: Article
Creator:: Vandusen, R., Tarr, Gary, Waldron, P. D., Celo, Dritan, Smy, Tom, and Albert, Jacques
Date Created:: 2008-03-10

22. Non enim ab hiis que sensus est iudicare sensum. Sensation and Thought in Theaetetus, Plotinus and Proclus

Resource Type:: Article
Creator:: MacIsaac, Gregory
Abstract:: I examine the relation between sensation and discursive thought (dianoia) in Plato, Plotinus, and Proclus. In Theaetetus, a soul whose highest faculty was sensation would have no unified experience of the sensible world, lacking universal ideas to give order to the sensible flux. It is implied that such universals are grasped by the soul's thinking. In Plotinus the soul is not passive when it senses the world, but as the logos of all things it thinks the world through its own forms. Proclus argues against the derivation of universal logoi from the senses, which alone can't make the sensible world comprehensible. At most they give a record of the original sense-impression in its particularity. The soul's own projected logoi give the sensible world stability. For Proclus, bare sensation does not depend on thought, but a unified experience of the sense-world depends on its paradigmatic logoi in our souls.
Date Created:: 2014-01-01

23. Peter the Venerable and Secular Friendships

Resource Type:: Article
Creator:: Saurette, Marc
Date Created:: 2010-02-02

24. Techno-economic assessment of solar assisted heat pump system retrofit in the Canadian housing stock

Resource Type:: Article
Creator:: Beausoleil-Morrison, Ian, Asaee, S. Rasoul, and Ugursal, V. Ismet
Abstract:: The techno-economic feasibility of retrofitting existing Canadian houses with solar assisted heat pump (SAHP) is investigated. The SAHP architecture is adopted from previous studies conducted for the Canadian climate. The system utilizes two thermal storage tanks to store excess solar energy for use later in the day. The control strategy is defined in order to prioritise the use of solar energy for space and domestic hot water heating purposes. Due to economic and technical constraints a series of eligibility criteria are introduced for a house to qualify for the retrofit. A model was built in ESP-r and the retrofit was introduced into all eligible houses in the Canadian Hybrid Residential End-Use Energy and GHG Emissions model. Simulations were conducted for an entire year to estimate the annual energy savings, and GHG emission reductions. Results show that the SAHP system performance is strongly affected by climatic conditions, auxiliary energy sources and fuel mixture for electricity generation. Energy consumption and GHG emission of the Canadian housing stock can be reduced by about 20% if all eligible houses receive the SAHP system retrofit. Economic analysis indicates that the incentive measures will likely be necessary to promote the SAHP system in the Canadian residential market.
Date Created:: 2017-01-01

25. Distributed evolutionary algorithm for co-optimization of building and district systems for early community energy masterplanning

Resource Type:: Article
Creator:: Bucking, Scott and Dermardiros, Vasken
Abstract:: Buildings play a significant role in climate change mitigation. In North America, energy used to construct and operate buildings accounts for some 40% of total energy use, largely originating from fossil fuels. The strategic reduction of these energy demands requires knowledge of potential upgrades prior to a building's construction. Furthermore, renewable energy generation integrated into buildings façades and district systems can improve the resiliency of community infrastructure. However, loads that are non-coincidental with on-site generation can cause load balancing issues. This imbalance is typically due to solar resources peaking at noon, whereas building loads typically peak in the morning and late afternoon or evenings. Ideally, the combination of on-site generation and localized storage could remedy such load balancing issues while reducing the need for fossil fuels. In response to these issues, this paper contributes a methodology that co-optimizes building designs and district technologies as an integrated community energy system. A distributed evolutionary algorithm is proposed that can navigate over 10154 potential community permutations. This is the first time in literature that a methodology demonstrates the co-optimization of buildings and district energy systems to reduce energy use in buildings and balance loads at this scale. The proposed solution is reproducible and scalable for future community masterplanning studies.
Date Created:: 2018-02-01

26. Techno-economic feasibility evaluation of air to water heat pump retrofit in the Canadian housing stock

Resource Type:: Article
Creator:: Beausoleil-Morrison, Ian, Asaee, S. Rasoul, and Ugursal, V. Ismet
Abstract:: This study was conducted to assess the techno-economic feasibility of converting the Canadian housing stock (CHS) into net/near zero energy buildings by introducing and integrating high efficient and renewable/alternative energy technologies in new construction and existing houses. Performance assessment of energy retrofit and renewable/alternative energy technologies in existing houses in regional and national scale is necessary to devise feasible strategies and incentive measures. The Canadian Hybrid Residential End-Use Energy and GHG Emissions model (CHREM) that utilizes a bottom-up modeling approach is used to investigate the techno-economic feasibility of air to water heat pump retrofit in the Canadian housing stock. The proposed energy retrofit includes an air to water heat pump, auxiliary boiler, thermal storage tank, hydronic heat delivery and domestic hot water (DHW) heating. Energy savings, GHG emission changes and economic feasibility of the air source heat pump retrofit are considered in this study. Results show that there is a potential to reduce 36% of energy consumption and 23% of GHG emissions of the CHS if all eligible houses undertake the retrofit. Economic analysis indicates that the feasibility of air to water heat pump systems is strongly affected by the current status of primary energy use for electricity generation and space and DHW heating as well as energy prices and economic conditions. Legislation, economic incentives and education for homeowners are necessary to enhance the penetration level of air to water heat pump retrofits in the CHS.
Date Created:: 2017-01-25

27. Electrical-end-use data from 23 houses sampled each minute for simulating micro-generation systems

Resource Type:: Article
Creator:: Beausoleil-Morrison, Ian and Johnson, Geoffrey
Abstract:: An improved understanding of the consumption patterns, end-uses, and temporal variations of electrical loads in houses is warranted because a significant fraction of a society's total electricity consumption occurs within residential buildings. In general, there is a lack of high-temporal-resolution data describing occupant electrical consumption that are available to researchers in this field. To address this, new measurements were performed and combined with data emanating from an earlier study to provide a database of annual measurements for 23 houses at a 1-min resolution that characterizes whole-house, non-HVAC, air conditioner, and furnace fan electrical draws, as well as the draw patterns of some major appliances. All houses were located in Ottawa, Canada. The non-HVAC measurements of this 23-house sample were shown to be in agreement with published estimates for the housing stock. The furnace fan was found to be the most significant end-use. These high-temporal-resolution data of electrical demands in houses can be used by researchers to increase the fidelity of building performance simulation analyses of different micro-generation technologies in residential buildings.
Date Created:: 2017-03-05

28. Micro-cogeneration versus conventional technologies: Considering model uncertainties in assessing the energy benefits

Resource Type:: Article
Creator:: Johnson, Geoffrey, Beausoleil-Morrison, Ian, and Wills, Adam
Abstract:: Fuel cells with nominal outputs of approximately 1kW AC are emerging as a prime-mover of a micro-cogeneration system potentially well-suited to compete, on an energy basis, with conventional methods for satisfying occupant electrical and thermal demands in a residential application. As the energy benefits of these systems can be incremental when compared to efficient conventional methods, it is especially important to consider the uncertainties of the models on which simulation results are based. However, researchers have yet to take this aspect into account.This article makes a contribution by demonstrating how these model uncertainties may be propagated to the simulation results of a micro-cogeneration system for comparison to a reference scenario using a case study. This case study compares the energy performance of a fuel-cell based micro-cogeneration system serving only domestic hot water demands to an efficient reference scenario where the conventional methods for providing electrical and thermal demands are considered to be a central gas-fired combined-cycle plant and a condensing tankless water heater respectively. The simulation results demonstrated that if model uncertainties were ignored, it would have been possible to demonstrate that the considered micro-cogeneration system was more efficient than the reference scenario for average consumption levels of domestic hot water. However, when model uncertainties were considered, the efficiency of the considered micro-cogeneration system could not reliably exceed that of the reference scenario by serving the domestic hot water needs of a single-family home.
Date Created:: 2017-03-05

29. Discussing stories: On how a dialogic reading intervention improves kindergartners' oral narrative construction

Resource Type:: Article
Creator:: Sénéchal, Monique and Lever, Rosemary
Abstract:: Oral narrative skills are assumed to develop through parent-child interactive routines. One such routine is shared reading. A causal link between shared reading and narrative knowledge, however, has not been clearly established. The present research tested whether an 8-week shared-reading intervention enhanced the fictional narrative skills of children entering formal education. Dialogic reading, a shared reading activity that involves elaborative questioning techniques, was used to engage children in oral interaction during reading and to emphasize elements of story knowledge. Forty English-speaking five- and six-year-olds were assigned to either the dialogic-reading or an alternative-treatment group. ANCOVA results found that the dialogic-reading children’s post-test narratives were significantly better on structure and context measures than those for the alternative-treatment children, but results differed for produced or retold narratives. The dialogic-reading children also showed expressive vocabulary gains. Overall, this study concretely determined that aspects of fictional narrative construction knowledge can be learned from interactive book reading.
Date Created:: 2011-01-01

30. Techno-economic assessment of photovoltaic (PV) and building integrated photovoltaic/thermal (BIPV/T) system retrofits in the Canadian housing stock

Resource Type:: Article
Creator:: Ugursal, V. Ismet, Beausoleil-Morrison, Ian, Nikoofard, Sara, and Asaee, S. Rasoul
Abstract:: Techno-economic impact of retrofitting houses in the Canadian housing stock with PV and BIPV/T systems is evaluated using the Canadian Hybrid End-use Energy and Emission Model. Houses with south, south-east and south-west facing roofs are considered eligible for the retrofit since solar irradiation is maximum on south facing surfaces in the northern hemisphere. The PV system is used to produce electricity and supply the electrical demand of the house, with the excess electricity sold to the grid in a net-metering arrangement. The BIPV/T system produces electricity as well as thermal energy to supply the electrical as well as the thermal demands for space and domestic hot water heating. The PV system consists of PV panels installed on the available roof surface while the BIPV/T system adds a heat pump, thermal storage tank, auxiliary heater, domestic hot water heating equipment and hydronic heat delivery system, and replaces the existing heating system in eligible houses. The study predicts the energy savings, GHG emission reductions and tolerable capital costs for regions across Canada. Results indicate that the PV system retrofit yields 3% energy savings and 5% GHG emission reduction, while the BIPV/T system yields 18% energy savings and 17% GHG emission reduction in the Canadian housing stock. While the annual electricity use slightly increases, the fossil fuel use of the eligible houses substantially decreases due to BIPV/T system retrofit.
Date Created:: 2017-10-01

31. Continuous approximate synthesis of planar function-generators minimising the design error

Resource Type:: Article
Creator:: Guigue, Alexis and Hayes, M. John
Abstract:: It has been observed in the literature that as the cardinality of the prescribed discrete input-output data set increases, the corresponding four-bar linkages that minimise the Euclidean norm of the design and structural errors tend to converge to the same linkage. The important implication is that minimising the Euclidean norm, or any p-norm, of the structural error, which leads to a nonlinear least-squares problem requiring iterative solutions, can be accomplished implicitly by minimising that of the design error, which leads to a linear least-squares problem that can be solved directly. Apropos, the goal of this paper is to take the first step towards proving that as the cardinality of the data set tends towards infinity the observation is indeed true. In this paper we will integrate the synthesis equations in the range between minimum and maximum input values, thereby reposing the discrete approximate synthesis problem as a continuous one. Moreover, we will prove that a lower bound of the Euclidean norm, and indeed of any p-norm, of the design error for planar RRRR function-generating linkages exists and is attained with continuous approximate synthesis.
Date Created:: 2016-07-01

32. An information driven hybrid evolutionary algorithm for optimal design of a Net Zero Energy House

Resource Type:: Article
Creator:: Bucking, Scott, Zmeureanu, Radu, and Athienitis, Andreas
Abstract:: Building Performance Simulation (BPS) is a powerful tool to estimate and reduce building energy consumption at the design stage. However, the true potential of BPS remains unrealized if trial and error simulation methods are practiced to identify combinations of parameters to reduce energy use of design alternatives. Optimization algorithms coupled with BPS is a process-orientated tool which identifies optimal building configurations using conflicting performance indicators. However, the application of optimization approaches to building design is not common practice due to time and computation requirements. This paper proposes a hybrid evolutionary algorithm which uses information gained during previous simulations to expedite and improve algorithm convergence using targeted deterministic searches. This technique is applied to a net-zero energy home case study to optimize trade-offs in passive solar gains and active solar generation using a cost constraint.
Date Created:: 2013-08-27

33. Escherian Reflections on the Charter and Human Rights in Canada

Resource Type:: Article
Creator:: Mac Neil, Michael
Date Created:: 2014-01-01

34. Full-scale Atlas motion platform: structure, actuation, and control

Resource Type:: Article
Creator:: Hayes, M.J.D., Jung, B., Langlois, Robert, and Copeland, Z.
Date Created:: 2016-01-01

35. Adaptation and validation of an existing bottom-up model for simulating temporal and inter-dwelling variations of residential appliance and lighting demands

Resource Type:: Article
Creator:: Beausoleil-Morrison, Ian, Wills, A. D., and Ugursal, V. I.
Abstract:: The design and analysis of community-scale energy systems and incentives is a non-trivial task. The challenge of such undertakings is the well-documented uncertainty of building occupant behaviours. This is especially true in the residential sector, where occupants are given more freedom of activity compared to work environments. Further complicating matters is the dearth of available measured data. Building performance simulation tools are one approach to community energy analysis, however such tools often lack realistic models for occupant-driven demands, such as appliance and lighting (AL) loads. For community-scale analysis, such AL models must also be able to capture the temporal and inter-dwelling variation to achieve realistic estimates of aggregate electrical demand. This work adapts the existing Centre for Renewable Energy Systems Technology (CREST) residential energy model to simulate Canadian residential AL demands. The focus of the analysis is to determine if the daily, seasonal, and inter-dwelling variation of AL demands estimated by the CREST model is realistic. An in-sample validation is conducted on the model using 22 high-resolution measured AL demand profiles from dwellings located in Ottawa, Canada. The adapted CREST model is shown to broadly capture the variation of AL demand variations observed in the measured data, however seasonal variation in daily AL demand behaviour was found to be under-estimated by the model. The average and variance of daily load factors was found to be similar between measured and modelled. The model was found to under-predict the daily coincidence factors of aggregated demands, although the variance of coincident factors was shown to be similar between measured and modelled. A stochastic baseload input developed for this work was found to improve estimates of the magnitude and variation of both baseload and peak demands.
Date Created:: 2017-09-05

36. In the Company of my Peers: Implementation of RDA in Canada

Resource Type:: Article
Creator:: Riva, Pat, Cross, Emma, Andrews, Sue, Oliver, Chris, and Grover, Trina
Abstract:: This article describes the progress made toward implementing Resource Description and Access (RDA) in libraries across Canada, as of Fall 2013. Differences in the training experiences in the English-speaking cataloging communities and French-speaking cataloging communities are discussed. Preliminary results of a survey of implementation in English-Canadian libraries are included as well as a summary of the support provided for French-Canadian libraries. Data analysis includes an examination of the rate of adoption in Canada by region and by sector. Challenges in RDA training delivery in a Canadian context are identified, as well as opportunities for improvement and expansion of RDA training in the future.
Date Created:: 2014-01-01

37. Publishing graduate student research in geography: the fundamentals

Resource Type:: Article
Creator:: Ballamingie, Patricia and Tudin, Susan
Date Created:: 2013-05-01

38. The Protean Challenge of Game Collections at Academic Libraries

Resource Type:: Article
Creator:: Cross, Emma, Smith, Robert, and Mould, David
Abstract:: The rise of game development and game studies on university campuses prompts academic libraries to consider how to support teaching and research in this area. This article examines current issues and challenges in the development of game collections at academic libraries. The gaming ecosystem has become more complex and libraries may need to move beyond collections largely based on console video games. This article will advance the discussion by considering emerging issues to support access to the full range of games. The article will use examples from Carleton University Library, Ottawa, which has been developing a game collection since 2008.
Date Created:: 2015-01-01

39. Apodised in-fibre Bragg grating reflectors photoimprinted using a phase mask

Resource Type:: Article
Creator:: Johnson, D. C., Theriault, S., Malo, B., Bilodeau, F., Hill, K. O., and Albert, Jacques
Abstract:: An apodized in-fibre Bragg grating reflector is fabricated using the phase mask photoimprinting technique. The reflector has a centre wavelength of 1550 nm, a bandwidth of 0.22 nm and a peak reflectivity of 90%. At 0.4 nm (50 GHz) from the centre wavelength the reflectivity is 40 dB lower than the peak reflectivity; this is an improvement of more than 20 dB over an unapodized Bragg grating reflector with similar bandwidth and peak reflectivity.
Date Created:: 1995-02-02

40. A Systematic Approach for Variable Selection With Random Forests: Achieving Stable Variable Importance Values

Resource Type:: Article
Creator:: Banks, Sarah N., Millard, Koreen, Behnamian, Amir, White, Lori, Richardson, Murray, and Pasher, Jon
Abstract:: Random Forests variable importance measures are often used to rank variables by their relevance to a classification problem and subsequently reduce the number of model inputs in high-dimensional data sets, thus increasing computational efficiency. However, as a result of the way that training data and predictor variables are randomly selected for use in constructing each tree and splitting each node, it is also well known that if too few trees are generated, variable importance rankings tend to differ between model runs. In this letter, we characterize the effect of the number of trees (ntree) and class separability on the stability of variable importance rankings and develop a systematic approach to define the number of model runs and/or trees required to achieve stability in variable importance measures. Results demonstrate that both a large ntree for a single model run, or averaged values across multiple model runs with fewer trees, are sufficient for achieving stable mean importance values. While the latter is far more computationally efficient, both the methods tend to lead to the same ranking of variables. Moreover, the optimal number of model runs differs depending on the separability of classes. Recommendations are made to users regarding how to determine the number of model runs and/or trees that are required to achieve stable variable importance rankings.
Date Created:: 2017-09-15

41. Chirped in-fibre Bragg grating dispersion compensators: Linearization of dispersion characteristic and demonstration of dispersion compensation in 100km, 10 Gbit/s optical fibre link

Resource Type:: Article
Creator:: Takiguchi, K., Johnson, D. C., Hill, K. O., Hagimoto, K., Kitagawa, T., Malo, B., Bilodeau, F., Theriault, S., Albert, Jacques, and Kataoka, T.
Abstract:: An apodized chirped in-fibre Bragg grating that has a linear dispersion characteristic is reported. The frequency components of an optical pulse (centre wavelength 1551 nm; 10 GHz bandwidth) incident on the grating are reflected with a relative delay that varies linearly from 0 to 130 ps across the spectral width of the pulse. The dispersion compensator is used to correct for the dispersion in a 100 km link (nondispersion shifted fibre) operating at a 10 Gbit/s transmission rate and a wavelength of 1551 nm.
Date Created:: 1994-10-13

42. Effective index drift from molecular hydrogen diffusion in hydrogen-loaded optical fibres and its effect on Bragg grating fabrication

Resource Type:: Article
Creator:: Johnson, D. C., Malo, B., Albert, Jacques, Bilodeau, F., and Hill, K. O.
Abstract:: When hydrogen loading is used to enhance the photosensitivity of silica-based optical waveguides and fibres, the presence of molecular hydrogen dissolved in the glass matrix changes the effective index of propagation of guided optical modes by as much as 0.05%. Real-time monitoring of the reflectivity spectrum of Bragg gratings written in such conditions shows that the centre wavelength follows the changes in hydrogen concentration due to diffusion and reaction with glass defects.
Date Created:: 1994-01-01

43. Enhanced photosensitivity in lightly doped standard telecommunication fibre exposed to high fluence ArF excimer laser light

Resource Type:: Article
Creator:: Hill, K. O., Albert, Jacques, Bilodeau, F., Johnson, D. C., Malo, B., and Theriault, S.
Abstract:: The core refractive index of Corning SMF-28 optical fibre exposed to ArF laser pulses increases with the square of the fluence per pulse. Bragg gratings with a refractive index modulation amplitude higher than 10 -3 have been obtained. This is an order of magnitude improvement over previously reported values for this type of fibre in the absence of treatment to enhance the photosensitivity.
Date Created:: 1995-05-25

44. Single-frequency Er3+-doped silica-based planar waveguide laser with integrated photo-imprinted Bragg reflectors

Resource Type:: Article
Creator:: Hibino, Y., Kitagawa, T., Hill, K. O., Bilodeau, F., Jihnson, D. C., Malo, B., Theriault, S., Albert, Jacques, and Hattori, K.
Abstract:: Single-longitudinal-mode operation of Er3+-P2O5-codoped silica planar waveguide lasers which are equipped with integrated Bragg grating reflectors is demonstrated, with a polarized output of 340 μW at 1546 nm. The gratings are photo-imprinted using 193 nm light exposure through a phase mask in GeO2-free optical waveguides that have been sensitized by H2 loading.
Date Created:: 1994-08-04

45. Strain-optic coefficients of individual cladding modes of singlemode fibre: Theory and experiment

Resource Type:: Article
Creator:: Albert, Jacques and Chen, Chengkun
Date Created:: 2006-09-05

46. Non-uniform-tilt-modulated fiber Bragg grating for temperature-immune micro-displacement measurement

Resource Type:: Article
Creator:: Chen, Chengkun, Guo, Tuan, and Albert, Jacques
Date Created:: 2009-04-10

47. Cross-section electrical resistance tomography of La Soufrière of Guadeloupe lava dome

Resource Type:: Article
Creator:: Lesparre, Nolwenn, Adler, Andy, Komorowski, Jean-Christophe, Grychtol, Bartłomiej, and Gibert, Dominique
Abstract:: The electrical resistivity distribution at the base of La Soufrière of Guadeloupe lava dome is reconstructed by using transmission electrical resistivity data obtained by injecting an electrical current between two electrodes located on opposite sides of the volcano. Several pairs of injection electrodes are used in order to constitute a data set spanning the whole range of azimuths, and the electrical potential is measured along a cable covering an angular sector of ≈120? along the basis of the dome. The data are inverted to performa slice electrical resistivity tomography (SERT) with specific functions implemented in the EIDORS open source package dedicated to electrical impedance tomography applied to medicine and geophysics. The resulting image shows the presence of highly conductive regions separated by resistive ridges. The conductive regions correspond to unconsolidated material saturated by hydrothermal fluids. Two of them are associated with partial flank collapses and may represent large reservoirs that could have played an important role during past eruptive events. The resistive ridges may represent massive andesite and are expected to constitute hydraulic barriers.
Date Created:: 2014-01-01

48. Plasmon-enhanced refractometry using silver nanowire coatings on tilted fibre Bragg gratings

Resource Type:: Article
Creator:: Bialiayeu, A., Ianoul, Anatoli, Prezgot, Dan, Bottomley, Adam, and Albert, Jacques
Abstract:: A novel technique for increasing the sensitivity of tilted fibre Bragg grating (TFBG) based refractometers is presented. The TFBG sensor was coated with chemically synthesized silver nanowires 100nm in diameter and several micrometres in length. A 3.5-fold increase in sensor sensitivity was obtained relative to the uncoated TFBG sensor. This increase is associated with the excitation of surface plasmons by orthogonally polarized fibre cladding modes at wavelengths near 1.5μm. Refractometric information is extracted from the sensor via the strong polarization dependence of the grating resonances using a Jones matrix analysis of the transmission spectrum of the fibre.
Date Created:: 2012-11-09

49. The differential impact of social defeat on mice living in isolation or groups in an enriched environment: Plasma corticosterone and monoamine variations

Resource Type:: Article
Creator:: Anisman, Hymie, Audet, Marie-Claude, McQuaid, Robyn J., and Jacobson-Pick, Shlomit
Abstract:: Social defeat in mice is a potent stressor that promotes the development of depressive- and anxiety-like behaviours, as well as variations of neuroendocrine and brain neurotransmitter activity. Although environmental enrichment may protect against some of the adverse behavioural and biological effects of social defeat, it seems that, among male group-housed mice maintained in an enriched environment (EE), aggressive behaviours may be more readily instigated, thus promoting distress and exacerbating psychopathological features. Thus, although an EE can potentially have numerous beneficial effects, these may depend on the general conditions in which mice were raised. It was observed in the current investigations that EE group-housed BALB/cByJ mice displayed increased anxiety-like behaviours compared to their counterparts maintained in a standard environment (SE). Furthermore, in response to social defeat, EE group-housed male mice exhibited decreased weight gain, exaggerated corticosterone elevations and altered hippocampal norepinephrine utilization compared to their SE counterparts. These effects were not apparent in the individually housed EE mice and, in fact, enrichment among these mice appeared to buffer against serotonin changes induced by social defeat. It is possible that some potentially beneficial effects of enrichment were precluded among group-housed mice, possibly owing to social disturbances that might occur in these conditions. In fact, even if social interaction is an essential feature of enrichment, it seems that some of the positive effects of this housing condition might be optimal when mice are housed individually, particularly with regard to buffering the effects of social defeat.
Date Created:: 2013-03-01

50. Phosphorylation of H,K-ATPase α-subunit in microsomes from rabbit gastric mucosa by cAMP-dependent protein kinase

Resource Type:: Article
Creator:: Rubtsov, Alexander M., Petukhov, Sergei P., Murtazina, Dilyara A., Lopina, Olga D., and Storey, Kenneth B.
Abstract:: A 100-kDa protein that is a main component of the microsomal fraction from rabbit gastric mucosa is phosphorylated by cAMP-dependent protein kinase (PKA) in the presence of 0.2% Triton X-100. Microsomes from rabbit gastric mucosa possess activity of H,K-ATPase but not activity of Na,K-ATPase. Incubation of microsomes with 5 μM fluorescein 5′-isothiocyanate (FITC) results in both an inhibition of H,K-ATPase and labeling of a protein with an electrophoretic mobility corresponding to the mobility of the protein phosphorylated by PKA. The data suggest that the α-subunit of H,K-ATPase can be a potential target for PKA phosphorylation.
Date Created:: 1999-07-27

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1. Difference in the behavior of oxygen deficient defects in Ge-doped silica optical fiber preforms under ArF and KrF excimer laser irradiation

2. Simultaneous corona poling of multiple glass layers for enhanced effective second-order optical nonlinearities

3. Si ion implantation-induced damage in fused silica probed by variable-energy positrons

4. Photosensitivity in phosphorus-doped silica glass and optical waveguides

5. 1 W tunable dual-wavelength emission from cascaded distributed feedback fiber lasers

6. A thin metal sheath lifts the EH to HE degeneracy in the cladding mode refractometric sensitivity of optical fiber sensors

7. Comparison of one-photon and two-photon effects in the photosensitivity of germanium-doped silica optical fibers exposed to intense ArF excimer laser pulses

8. Bragg gratings fabricated in monomode photosensitive optical fiber by UV exposure through a phase mask

9. Four-wave mixing in carbon nanotube-coated optical fiber gratings

10. Fabrication of electron beam generated, chirped, phase mask (1070 . 11 – 1070 . 66 nm) for fiber Bragg grating dispersion compensator

11. Formation and bleaching of strong ultraviolet absorption bands in germanium implanted synthetic fused silica

12. Ion implantation-induced strong photosensitivity in high-purity fused silica: Correlation of index changes with VUV color centers

13. Potassium and silver ion-exchanged dual-core glass waveguides with gratings

14. Maskless writing of submicrometer gratings in fused silica by focused ion beam implantation and differential wet etching

15. Au-coated tilted fiber Bragg grating twist sensor based on surface plasmon resonance

16. Strong Bragg gratings in phosphate glass single mode fiber

17. Field-assisted patterned dissolution of silver nanoparticles in phosphate glass

18. Analysis of Piezoelectric Ice Protection Systems Combined with Ice-Phobic Coatings

19. Fabrication of a variable diffraction efficiency phase mask by multiple dose ion implantation

20. Environmental controls of frost cracking revealed through in situ acoustic emission measurements in steep bedrock

21. Low temperature plasma etching for Si3 N4 waveguide applications

22. Non enim ab hiis que sensus est iudicare sensum. Sensation and Thought in Theaetetus, Plotinus and Proclus

23. Peter the Venerable and Secular Friendships

24. Techno-economic assessment of solar assisted heat pump system retrofit in the Canadian housing stock

25. Distributed evolutionary algorithm for co-optimization of building and district systems for early community energy masterplanning

26. Techno-economic feasibility evaluation of air to water heat pump retrofit in the Canadian housing stock

27. Electrical-end-use data from 23 houses sampled each minute for simulating micro-generation systems

28. Micro-cogeneration versus conventional technologies: Considering model uncertainties in assessing the energy benefits

29. Discussing stories: On how a dialogic reading intervention improves kindergartners' oral narrative construction

30. Techno-economic assessment of photovoltaic (PV) and building integrated photovoltaic/thermal (BIPV/T) system retrofits in the Canadian housing stock

31. Continuous approximate synthesis of planar function-generators minimising the design error

32. An information driven hybrid evolutionary algorithm for optimal design of a Net Zero Energy House

33. Escherian Reflections on the Charter and Human Rights in Canada

34. Full-scale Atlas motion platform: structure, actuation, and control

35. Adaptation and validation of an existing bottom-up model for simulating temporal and inter-dwelling variations of residential appliance and lighting demands

36. In the Company of my Peers: Implementation of RDA in Canada

37. Publishing graduate student research in geography: the fundamentals

38. The Protean Challenge of Game Collections at Academic Libraries

39. Apodised in-fibre Bragg grating reflectors photoimprinted using a phase mask

40. A Systematic Approach for Variable Selection With Random Forests: Achieving Stable Variable Importance Values

41. Chirped in-fibre Bragg grating dispersion compensators: Linearization of dispersion characteristic and demonstration of dispersion compensation in 100km, 10 Gbit/s optical fibre link

42. Effective index drift from molecular hydrogen diffusion in hydrogen-loaded optical fibres and its effect on Bragg grating fabrication

43. Enhanced photosensitivity in lightly doped standard telecommunication fibre exposed to high fluence ArF excimer laser light

44. Single-frequency Er3+-doped silica-based planar waveguide laser with integrated photo-imprinted Bragg reflectors

45. Strain-optic coefficients of individual cladding modes of singlemode fibre: Theory and experiment

46. Non-uniform-tilt-modulated fiber Bragg grating for temperature-immune micro-displacement measurement

47. Cross-section electrical resistance tomography of La Soufrière of Guadeloupe lava dome

48. Plasmon-enhanced refractometry using silver nanowire coatings on tilted fibre Bragg gratings

49. The differential impact of social defeat on mice living in isolation or groups in an enriched environment: Plasma corticosterone and monoamine variations

50. Phosphorylation of H,K-ATPase α-subunit in microsomes from rabbit gastric mucosa by cAMP-dependent protein kinase

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