Research

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  • Water-in-water droplets by passive microfluidic flow focusing
    Water-in-water droplets by passive microfluidic flow focusing
    We present a simple microfluidic system that generates water-in-water, aqueous two phase system (ATPS) droplets, by passive flow focusing. ATPS droplet formation is achieved by applying weak hydrostatic pressures, with liquid-filled pipette tips as fluid columns at the inlets, to introduce low speed flows to the flow focusing junction. To control the size of the droplets, we systematically vary the interfacial tension and viscosity of the ATPS fluids, and adjust the fluid column height at the fluid inlets. The size of the droplets scales with a power-law of the ratio of viscous stresses in the two ATPS phases. Overall, we find a drop size coefficient of variation (CV; i.e. polydispersity) of about 10 %. We also find that when drops form very close to the flow focusing junction, the drops have CV of less than 1 %. Our droplet generation method is easily scalable: we demonstrate a parallel system that generates droplets simultaneously, and improves the droplet production rate by up to one order-of-magnitude. Finally, we show the potential application of our system for encapsulating cells in water-in-water emulsions, by encapsulating microparticles and cells. To the best of our knowledge, our microfluidic technique is the first that forms low interfacial tension ATPS droplets without applying external perturbations. We anticipate that this simple approach will find utility in drug and cell delivery applications because of the all-biocompatible nature of the water-in-water ATPS environment., Moon, B., Abbasi, N., Jones, S. G., Hwang, D. K., & Tsai, S. S. (n.d.). Water-in-water droplets by passive microfluidic flow focusing (pp. 1-25, Publication). Toronto, Ontario: Department of Mechanical and Industrial Engineering, Ryerson University., E-mail: dkhwang@ryerson.ca; scott.tsai@ryerson.ca
    Wavelength-Switchable Dissipative Soliton Fiber Laser With a Chirped Fiber Grating Stop-Band Filter
    Wavelength-Switchable Dissipative Soliton Fiber Laser With a Chirped Fiber Grating Stop-Band Filter
    We report a wavelength-switchable single-polarization dissipative soliton (DS) mode-locked fiber laser using a chirped fiber Bragg grating (FBG) for spectral filtering. The chirped FBG, when inserted into the ring cavity, provides a stopband from 1045 nm to 1057 nm, which is used for spectral filtering in this all-normal-dispersion mode-locked Yb-doped fiber laser. The combination of the chirped FBG and the Yb gain profile help the formation of the DS. The laser delivers wavelength-switchable and polarized (28 dB) DS of 6.1 nJ and 29 ps at 1032 nm, and 4.3 nJ and 24 ps at 1068 nm, respectively. To the best of our knowledge, this is the direct proof that a bandpass filter is not indispensible to achieve stable DS in ps fiber lasers., Zhang, L., Feng, Y., & Gu, X. (2013). Wavelength-switchable dissipative soliton fiber laser with a chirped fiber grating stop-band filter. IEEE Photonics Journal, 5(2), 1500506-1500506. doi:10.1109/JPHOT.2013.2252608
    Wealth effects in a cash-in-advance economy
    Wealth effects in a cash-in-advance economy
    Also available for download here: https://ideas.repec.org/a/ebl/ecbull/eb-03e00001.html
    Wearable Hardware Design for the Internet of Medical Things (IoMT)
    Wearable Hardware Design for the Internet of Medical Things (IoMT)
    As the life expectancy of individuals increases with recent advancements in medicine and quality of living, it is important to monitor the health of patients and healthy individuals on a daily basis. This is not possible with the current health care system in North America, and thus there is a need for wireless devices that can be used from home. These devices are called biomedical wearables, and they have become popular in the last decade. There are several reasons for that, but the main ones are: expensive health care, longer wait times, and an increase in public awareness about improving quality of life. With this, it is vital for anyone working on wearables to have an overall understanding of how they function, how they were designed, their significance, and what factors were considered when the hardware was designed. Therefore, this study attempts to investigate the hardware components that are required to design wearable devices that are used in the emerging context of the Internet of Medical Things (IoMT). This means that they can be used, to an extent, for disease monitoring through biosignal capture. In particular, this review study covers the basic components that are required for the front-end of any biomedical wearable, and the limitations that these wearable devices have. Furthermore, there is a discussion of the opportunities that they create, and the direction that the wearable industry is heading in., Qureshi, F., & Krishnan, S. (2018). Wearable hardware design for the internet of medical things (IoMT). Sensors, 18(11), 3812., (This article belongs to the Special Issue Wireless Body Area Networks and Connected Health)
    Web-based Spatial Decision Support: Status and Research Directions
    Web-based Spatial Decision Support: Status and Research Directions
    https://www.semanticscholar.org/paper/Web-based-Spatial-Decision-Support%3A-Status-and-Rinner/e72fce147fb768143101e7cf7c20f314f5855e40, This paper summarizes research on Web-based spatial decision support systems (WebSDSS). The review distinguishes early server-side from more recent client-side applications. A third category of WebSDSS focusing on spatial decision support in public participation is typically implemented as a mixed client/server-based system. Conclusions drawn from previous work include the need for systematic user studies of WebSDSS, and the adoption of interoperable architectures for distributed spatial decision support. Furthermore, a conceptual framework is proposed to facilitate further studies of WebSDSS methods.
    Welcome to Canada? A critical review and assessment of Canada’s fast-changing immigration policies : a literature review
    Welcome to Canada? A critical review and assessment of Canada’s fast-changing immigration policies : a literature review
    Since July 1st, 2012, Canada’s immigration system has been undergoing a significant and rapid transformation. This transformation has created a cloud of uncertainty for many prospective immigrants and unpredictability for policy analysts, non-state actors, scholars, and other stakeholders. While family reunification, economic immigration, and asylum for refugees have, in the past, enabled Canada to step up as a global leader, today concerns are growing that recent policy shifts are making Canada less desirable, are unfair to migrants and their families, and are resulting in destruction of its international reputation and long-held leadership in immigrant integration and settlement. The purpose of this paper is to build upon Alboim and Cohl’s Maytree report and review of both proposed and effective immigration policies from between July 2012 and July 2014. It describes some of the major policy amendments and evaluate their potential impact on all involved parties.
    Welfare effects of preferential trade agreements under optimal tariffs
    Welfare effects of preferential trade agreements under optimal tariffs
    Also available for download here: http://mpra.ub.uni-muenchen.de/17562/
    What If There Is No Killer Application? An Exploration of a User-Centric Perspective on Broadband
    What If There Is No Killer Application? An Exploration of a User-Centric Perspective on Broadband
    This paper explores user and provider experiences with broadband networks. Drawing on data from an early broadband trial and from recent studies of consumer broadband usage, the validity of the commonly held view that widespread adoption of broadband is dependent upon the development of a killer application is challenged. It is argued that access to broadband can be valuable for users without the provision of a killer application and that the dynamics of broadband development are shifting. As more users become content creators and distributors and as it becomes easier for consumers to establish broadband networks without help from traditional providers, the existing relationships within the broadband industry will change. Broadband researchers and stakeholders in the development of broadband networks are encouraged to explore and understand the implications of these changes, recognizing that there is much to be learned about deploying broadband in ways that will create the broad societal benefits promised by its promoters., Preprint of an article later published as: Middleton, C. A. (2003). What If There Is No Killer Application? An Exploration of a User-Centric Perspective on Broadband. Journal of Information Technology, 18(4), 231-246. Publisher URL: http://www.informaworld.com/openurl?genre=article&issn=0268%2d3962&volume=18&issue=4&spage=231
    What Makes Journalism “Excellent”? Criteria Identified by Judges in Two Leading Awards Programs
    What Makes Journalism “Excellent”? Criteria Identified by Judges in Two Leading Awards Programs
    What does “excellence” mean in journalism? The literature reveals no universally agreed set of standards, and awards guidelines are often unclear. We interviewed judges in two leading Canadian print journalism awards programs, using a sequence of open-ended and ranking questions to probe their criteria of excellence in a way calculated to elicit not just the standards they felt should be applied but the standards they actually did apply. Judges mentioned a wide variety of criteria, including the social importance and impact of works of journalism. But only two values were affirmed consistently: writing style and reporting rigour., Shapiro, I., Albanese, P., & Doyle, L. (2006). What Makes Journalism “Excellent”? Criteria Identified by Judges in Two Leading Awards Program, Canadian Journal of Communication, 31(2), 425-445. Retrieved from http://www.cjc-online.ca/index.php/journal/article/view/1743
    What are Chinese immigrant parents' concerns with their children's education?
    What are Chinese immigrant parents' concerns with their children's education?
    This study investigated teachers’ experiences of communicating with Chinese immigrant parents. Twenty teachers were recruited for interviews from local schools that had a large enrollment of Chinese immigrant students. Participating teachers reported that Chinese immigrant parents often expect high marks from their children and want to know their child’s ranking in the class. These parents also place pressure on children to achieve parentally-established goals. Participating teachers view a well-rounded education as the purpose of schooling, rather than high marks. They were frustrated by parents’ concern over children’s class ranking, and the parental focus on children’s perceived weaknesses. Teachers also reported that Chinese parents should ease the pressure they place on children, suggesting that parents should encourage children to participate in extra-curricular activities. They also suggested that Chinese parents should be more sensitive to their children’s preferences. Key words: Chinese immigrant parents, teacher-parent communication, culture, parental involvement