Ryerson University

About: Ryerson University is a education organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Computer science & Population. The organization has 7671 authors who have published 20164 publications receiving 394976 citations. The organization is also known as: Ryerson Polytechnical Institute & Ryerson Institute of Technology.

Effect of alloying elements on the segregation and dissolution of CuAl2 phase in Al-Si-Cu 319 alloys

Abstract: The hypoeutectic 319 aluminum alloy (Al-7%Si-3.5%Cu) was used in the present study to investigate the effect of diverse alloying elements on the dissolution of the copper phase (CuAl2) during solution heat treatment. Elements such as Sr, Fe and P were added to the base alloy individually and in various combinations. The cooling curves of these alloys were obtained by solidifying the alloy melts in a preheated graphite mold (600°C, cooling rate ∼0.8°C/s). From these the first derivate curves were plotted and used to determine the effect of the additives on the precipitation temperature of the Al-CuAl2 eutectic reaction. Microstructural examination was carried out using optical microscopy, image analysis, and electron probe microanalysis (EPMA), with energy dispersive X-ray (EDX) and wavelength dispersive spectroscopic (WDS) analysis facilities. Samples from different alloys were solution heat treated at 505°C for various times up to 100 hours. The results explicitly reveal that solution heat treatment plays a critical role on the dissolution of the CuAl2 phase. It is found that Sr leads to segregation of the CuAl2 phase away from the Al-Si eutectic regions, which slows down its dissolution during solution heat treatment. The β-Al5FeSi phase platelets act as preferred precipitation sites for the copper phase and hence lessen the degree of segregation. Thus, addition of Fe can accelerate the copper phase dissolution. However, phosphorus addition has a negative effect on CuAl2 dissolution due to (i) its solubility in the CuAl2 phase particles, and (ii) the formation of (Al,P)O2 oxide particles which act as nucleation sites for the precipitation of the block-like CuAl2 phase. It retards the complete dissolution of this copper phase even after 100 hr solution treatment. In the case when phosphorus and iron are added together, the negative effect of phosphorus can be neutralized to some extent.

Chinese Immigrants in Canada: Their Changing Composition and Economic Performance1

Abstract: Using landing records and tax data, this paper examines both the changing composition of the Chinese immigrants in Canada in the past two decades and their levels of economic performance. Our research found that, in addition to a shift in origin, economic immigrants have been on the rise and other classes of immigrants have declined. This has been accompanied by a significant increase in their educational qualifications and proficiency in a Canadian official language. Yet, despite their increased human capital, Chinese immigrants still experience very different economic outcomes in the Canadian labour market compared to members of the general population of Canada. For one thing, they have much lower employment and self-employment income than the general population. Moreover, these earning differentials hold true for all age groups, both genders, and Chinese immigrants from all origins. While their levels of economic performance increases with length of residency in Canada, this study suggests that it would take more than 20 years for Chinese immigrants to close the earning gaps with the general population. Evidence also suggests that Canadian-specific educational credentials are indeed worth more than those acquired in the immigrants' country of origin, and are much better remunerated by Canadian employers. IMMIGRES CHINOIS AU CANADA: EVOLUTION DE LEURS COMMUNAUTES ET DE LEUR REUSSITE ECONOMIQUE En s'appuyant sur les releves d'embarquement et les donnees des services fiscaux, les auteurs examinent a la fois l'evolution de la composition des com-munautes chinoises immigrees au Canada au cours des deux dernieres decennies et le niveau de leur reussite economique. Ils constatent que, outre un glissement au niveau des regions d'origine, les immigres economiques sont de plus en plus nombreux, tandis que d'autres categories d'immigres sont en recul. Cette evolution s'accompagne d'un relevement significatif du niveau d'instruction et de la connaissance des langues officielles du Canada. Cependant, malgre l'accroissement de leur capital humain, les immigres chinois connaissent tou-jours des fortunes tres differentes sur le marche du travail canadien, si on les compare avec la population canadienne en general. D'une part, leurs revenus en qualite de salaries ou d'independants sont nettement inferieurs a ceux de la population generale. D'autre part, les ecarts de revenus se verifient pour toutes les tranches d'âge et pour les deux sexes, et la region d'origine ne change rien a la donne. Alors que le niveau de reussite economique s'ameliore au fil des ans, cette etude montre qu'il faudrait plus de 20 ans aux immigres chinois pour se hisser au niveau de revenu de la population generale. Elle demontre egalement que les diplomes acquis au Canada sont nettement plus valorises que ceux acquis dans le pays d'origine des migrants et que leurs titulaires sont nettement mieux remuneres par les employeurs canadiens. INMIGRANTES CHINOS EN EL CANADA: CAMBIOS EN SU COMPOSICION Y RENDIMIENTO ECONOMICO Gracias a los registros de entrada en el pais y de pago de impuestos a la renta, en este documento se examina la variacion de las ultimas dos decadas en la composicion de los inmigrantes chinos en el Canada y en su rendimiento economico. En este estudio se determina que, ademas de provenir ahora de distintos lugares de origen, los inmigrantes economicos no dejan de aumentar mientras que las demas categorias de inmigrantes disminuyen. Ello se acompana de un considerable incremento en sus calificaciones educativas y del conocimiento de uno de los idiomas oficiales del Canada. Sin embargo, a pesar del creciente capital humano, los inmigrantes chinos siguen experimentando, en general, resultados economicos sumamente diferentes en el mercado laboral canadiense en comparacion al resto de la poblacion del Canada. Por una parte, tienen tasas de ingresos muy inferiores en empleo y autoempleo que el resto de la poblacion. Por otra, la diferencia de ingresos es valida para todos los grupos de edad, para ambos generos, y para los inmigrantes chinos de cualquier parte. Si bien el nivel de rendimiento economico aumenta con la duracion de la residencia en el Canada, este estudio apunta a que los inmigrantes chinos tardarian mas de 20 anos en colmar las brechas salariales con el resto de la poblacion. Tambien se demuestra que las credenciales educativas especificas canadienses valen mucho mas que aquellas adquiridas por los inmigrantes en su pais de origen y, por ende, son mejor remuneradas por los empleadores canadienses.

Resource Allocation Techniques in Cooperative Cognitive Radio Networks

Abstract: In the past decade, cognitive radio and cooperative communication techniques have been proposed in the literature for efficiently utilizing the radio resources. Cognitive radio is an emerging technology intended to enhance the utilization of the radio frequency spectrum. The cooperative communication system, with the same total power and bandwidth of legacy wireless communication systems, can increase the data rate of the future wireless communication system. A combination of cognitive radio with cooperative communication can further improve the future wireless network performance. Efficient resource allocation in cooperative cognitive radio network (CRN) is essential in order to meet the challenges of future wireless networks. In this article, a survey of resource allocation in cooperative CRN is presented. We discuss the taxonomy of objectives and protocols used in the literature for resource allocation in cooperative CRN. This paper also highlights the use of power control, cooperation types, network configurations and decision types used in cooperative CRN. Finally, directions for future research are outlined.

Cultural adaptation and translation of measures: An integrated method

Abstract: Differences in the conceptualization and operationalization of health-related concepts may exist across cultures. Such differences underscore the importance of examining conceptual equivalence when adapting and translating instruments. In this article, we describe an integrated method for exploring conceptual equivalence within the process of adapting and translating measures. The integrated method involves five phases including selection of instruments for cultural adaptation and translation; assessment of conceptual equivalence, leading to the generation of a set of items deemed to be culturally and linguistically appropriate to assess the concept of interest in the target community; forward translation; back translation (optional); and pre-testing of the set of items. Strengths and limitations of the proposed integrated method are discussed.