Research

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  • Transient response of laminar premixed flame to a radially diverging/converging flow
    Transient response of laminar premixed flame to a radially diverging/converging flow
    Laminar flamelets are often used to model premixed turbulent combustion. The libraries of rates of conversion from chemical to thermal enthalpies used for flamelets are typically based on counter-flow, stained laminar planar flames under steady conditions. The current research seeks further understanding of the effect of stretch on premixed flames by considering laminar flame dynamics in a cylindrically-symmetric outward radial flow geometry (i.e., inwardly propagating flame). This numerical model was designed to study the flame response when the flow and scalar fields align (i.e., no tangential strain on the flame) while the flame either expands (positive stretch) or contracts (negative stretch, which is a case that has been seldom explored) radially. The transient response of a laminar premixed flame has been investigated by applying a sinusoidal variation of mass flow rate at the inlet boundary with different frequencies to compare key characteristics of a steady unstretched flame to the dynamics of an unsteady stretched flame. An energy index (EI), which is the integration of the source term in the energy equation over all control volumes in the computational domain, was selected for the comparison. The transient response of laminar premixed flames, when subjected to positive and negative stretch, results in amplitude decrease and phase shift increase with increasing frequency. Other characteristics, such as the deviation of the EI at the mean mass flow rate between when the flame is expanding and contracting, are nonmonotonic with frequency. Also, the response of fuel lean flames is more sensitive to the frequency of the periodic stretching compared to a stoichiometric flame. An analysis to seek universality of transient flame responses across lean methane-air flames of different equivalence ratios (i.e., 1.0 to 0.7) using Damköhler Numbers (i.e., the ratio of a flow to chemical time scales) had limited success., Sahafzadeh, M., Kostiuk, L. W., & Dworkin, S. B. (2017). Transient response of a laminar premixed flame to a radially diverging/converging flow. Combustion and Flame, 179, 51-62. https://doi.org/10.1016/j.combustflame.2017.01.015
    Transmission Ultrasound to guide Minimally Invasive Thermal Therapy
    Transmission Ultrasound to guide Minimally Invasive Thermal Therapy
    Online version of a conference paper originally published as: Transmission Ultrasound to guide Minimally Invasive Thermal Therapy, E. Soleimankhani and M.C.Kolios (2007), In Proceedings of the 2007 IEEE International Ultrasonics Symposium, pp.2481-2484 Publisher URL: http://ieeexplore.ieee.org/iel5/4409572/4409573/04410029.pdf?arnumber=4410029
    Transnational, Multi-Local Motherhood: Experiences of Separation and Reunification among Latin American Families in Canada
    Transnational, Multi-Local Motherhood: Experiences of Separation and Reunification among Latin American Families in Canada
    Originally published as: Bernhard, J. K., Landolt, P., & Goldring, L. (2005). Transnational, multi-local motherhood: Experiences of separation and reunification among Latin American families in Canada. CERIS Working Paper No. 40.
    Transnationalizing Families: Canadian Immigration Policy and the Spatial Fragmentation of Care-giving among Latin American Newcomers
    Transnationalizing Families: Canadian Immigration Policy and the Spatial Fragmentation of Care-giving among Latin American Newcomers
    Preprint of an article later published as: Bernhard, Judith K.; Landolt, Patricia; Goldring, Luin. Transnationalizing Families: Canadian Immigration Policy and the Spatial Fragmentation of Care-giving among Latin American Newcomers . International Migration, Volume 47, Number 2, June 2009, pp. 3-31(29).
    Travel and us: The impact of mode share on sentiment using geo-social media and GIS
    Travel and us: The impact of mode share on sentiment using geo-social media and GIS
    Commute stress is a serious health problem that impacts nearly everyone. Considering that microblogged geo-locational information offers new insight into human attitudes, the present research examined the utility of geo-social media data for understanding how different active and inactive travel modes affect feelings of pleasure, or displeasure, in two major U.S. cities: Chicago, Illinois and Washington D.C. A popular approach was used to derive a sentiment index (pleasure or valence) for each travel Tweet. Methodologically, exploratory spatial data analysis (ESDA) and global and spatial regression models were used to examine the geography of all travel modes and factors affecting their valence. After adjusting for spatial error associated with socioeconomic, environmental, weather, and temporal factors, spatial autoregression models proved superior to the base global model. The results showed that water and pedestrian travel were universally associated with positive valences. Bicycling also favorably influenced valence, albeit only in D.C. A noteworthy finding was the negative influence temperature and humidity had on valence. The outcomes from this research should be considered when additional evidence is needed to elevate commuter sentiment values in practice and policy, especially in regards to active transportation., Greg Rybarczyk, Syagnik Banerjee, Melissa D. Starking-Szymanski & Richard R. Shaker (2018) Travel and us: the impact of mode share on sentiment using geo-social media and GIS, Journal of Location Based Services, 12:1, 40-62, DOI: 10.1080/17489725.2018.1468039
    Trees in Canadian Cities: Indispensable Life Form for Urban Sustainability
    Trees in Canadian Cities: Indispensable Life Form for Urban Sustainability
    We argue that a healthy urban forest contributes immensely to the sustainability of cities. The argument is based on a comprehensive array of values elicited from Canadians in several cities. To begin, we define the urban forest as inclusive of all the trees in the city and thus representing the predominant contributor to a city’s green infrastructure. Then we enumerate and explain the broad diversity of ways in which urban people value trees in the city. We, thus, show the myriad pathways by which trees contribute positively to any city’s social, economic, and ecological sustainability. Following a short summary of the ways in which trees may detract from people’s quality of life, we present promising management directions for urban-forest improvement, as we understand the situation in Canada. We conclude that all cities can enhance their sustainability by improving the urban forest., Duinker, P. N., Ordóñez, C., James W N Steenberg, Miller, K. H., Toni, S. A., & Nitoslawski, S. A. (2015). Trees in canadian cities: Indispensable life form for urban sustainability. Basel: MDPI AG. doi:10.3390/su7067379, (This article belongs to the Special Issue Planning, Development and Management of Sustainable Cities)
    Trends in the Usage of ISI Bibliometric Data: Uses, Abuses, and Implications
    Trends in the Usage of ISI Bibliometric Data: Uses, Abuses, and Implications
    Originally published in: portal: Libraries and the Academy, 5(1): 105-125, 2005. http://muse.jhu.edu/article/177787
    Troubled Relationships in Early Childhood Education: Parent-Teacher Interactions in Ethnoculturally Diverse Child Care Settings
    Troubled Relationships in Early Childhood Education: Parent-Teacher Interactions in Ethnoculturally Diverse Child Care Settings
    Online version of an article originally published as: Bernhard, Judith K., Marie Louise Lefebvre, Kenise Murphy Kilbride, Gyda Chud and Rika Lange. 1998. Troubled Relationships in Early Childhood Education: Parent–Teacher Interactions in Ethnoculturally Diverse Child Care Settings. Early Education & Development. 9(1):5-28. < Publisher URL: http://www.informaworld.com/10.1207/s15566935eed0901_1 >.
    Trunk muscle co-activation using functional electrical stimulation modifies center of pressure fluctuations during quiet sitting by increasing trunk stiffness
    Trunk muscle co-activation using functional electrical stimulation modifies center of pressure fluctuations during quiet sitting by increasing trunk stiffness
    Background The purpose of this study was to examine the impact of functional electrical stimulation (FES) induced co-activation of trunk muscles during quiet sitting. We hypothesized that FES applied to the trunk muscles will increase trunk stiffness. The objectives of this study were to: 1) compare the center of pressure (COP) fluctuations during unsupported and FES-assisted quiet sitting - an experimental study and; 2) investigate how FES influences sitting balance - an analytical (simulation) study. Methods The experimental study involved 15 able-bodied individuals who were seated on an instrumented chair. During the experiment, COP of the body projected on the seating surface was calculated to compare sitting stability of participants during unsupported and FES-assisted quiet sitting. The analytical (simulation) study examined dynamics of quiet sitting using an inverted pendulum model, representing the body, and a proportional-derivative (PD) controller, representing the central nervous system control. This model was used to analyze the relationship between increased trunk stiffness and COP fluctuations. Results In the experimental study, the COP fluctuations showed that: i) the mean velocity, mean frequency and the power frequency were higher during FES-assisted sitting; ii) the frequency dispersion for anterior-posterior fluctuations was smaller during FES-assisted sitting; and iii) the mean distance, range and centroidal frequency did not change during FES-assisted sitting. The analytical (simulation) study showed that increased mechanical stiffness of the trunk had the same effect on COP fluctuations as the FES. Conclusions The results of this study suggest that FES applied to the key trunk muscles increases the speed of the COP fluctuations by increasing the trunk stiffness during quiet sitting., Milosevic, M., Masani, K., Wu, N., McConville, K. M. V., & Popovic, M. R. (2015). Trunk muscle co-activation using functional electrical stimulation modifies center of pressure fluctuations during quiet sitting by increasing trunk stiffness. Journal of Neuroengineering and Rehabilitation, 12, 99.
    Truth, Superassertability, and Conceivability
    Truth, Superassertability, and Conceivability
    The superassertability theory of truth, inspired by Crispin Wright (1992, 2003), holds that a statement is true iff it is superassertable in the following sense: it possesses warrant that cannot be defeated by any improvement of our information. While initially promising, the superassertability theory of truth is vulnerable to a persistent difficulty highlighted by Van Cleve (1996) and Horgan (1995) but not properly fleshed out: it is formally/informally illegitimate in a similar sense that unsophisticated epistemic theories of truth (theories that identify truth with bare warranted assertability) are widely acknowledged to be. Sustained analysis reveals that the unrestricted formal/informal legitimacy argument is firmly grounded in first-person conceivability/possibility evidence.
    Trying to Smart-In-Up and Cleanup Our Act by Linking Regional Growth Planning, Brownfields Remediation, and Urban Infill in Southern Ontario Cities
    Trying to Smart-In-Up and Cleanup Our Act by Linking Regional Growth Planning, Brownfields Remediation, and Urban Infill in Southern Ontario Cities
    The reuse of brownfields as locations for urban intensification has become a core strategy in government sustainability efforts aimed at remediating pollution, curbing sprawl and prioritizing renewal, regeneration, and retrofitting. In Ontario, Canada’s most populous, industrialized, and brownfield-laden province, a suite of progressive policies and programs have been introduced to not only facilitate the assessment and remediation of the brownfields supply, but to also steer development demand away from peripheral greenfields and towards urban brownfields in a manner that considers a wider regional perspective. This article examines the character and extent of brownfields infill development that has taken place in three Ontario cities (Toronto, Waterloo, and Kingston) since the provincial policy shift in the early 2000s. Using property assessment data and cleanup records, the research finds that redevelopment activity has been extensive in both scale and character, particularly in Toronto where the real estate market has been strong. While the results are promising in terms of government efforts to promote smarter growth that builds “in and up” instead of out, they also reveal that government could be doing more to facilitate redevelopment and influence its sustainability character, particularly in weaker markets., Sousa, C. D. (2017). Trying to smart-in-up and cleanup our act by linking regional growth planning, brownfields remediation, and urban infill in southern Ontario cities. Urban Planning, 2(3), 5-17. doi:10.17645/up.v2i3.1026
    Trypan Blue Dye Enters Viable Cells Incubated with the Pore-Forming Toxin HlyII of Bacillus cereus
    Trypan Blue Dye Enters Viable Cells Incubated with the Pore-Forming Toxin HlyII of Bacillus cereus
    Tran S-L, Puhar A, Ngo-Camus M, Ramarao N (2011) Trypan Blue Dye Enters Viable Cells Incubated with the Pore-Forming Toxin HlyII of Bacillus cereus. PLoS ONE 6(9): e22876. doi:10.1371/journal.pone.0022876