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.

Modeling and control of automated polishing/deburring process using a dual-purpose compliant toolhead

Abstract: In this paper, a new approach is presented for modeling and control of an automated polishing/ deburring process that utilizes a dual-purpose compliant toolhead. This toolhead has a pneumatic spindle that can be extended and retracted by three pneumatic actuators to provide tool compliance. By integrating a pressure sensor and a linear encoder, this toolhead can be used for polishing and deburring. For the polishing control, the tool pressure is pre-planned based on the given part geometry, and a PID controller is applied for pressure tracking though pressure sensing. For the deburring control, another PID controller is applied to regulate the tool length through tool extension sensing. The two control methods have been tested and implemented on a polishing/deburring robot, and the experiment results demonstrate the effectiveness of the presented methods.

Advanced cell culture platforms: a growing quest for emulating natural tissues

Abstract: In the body, cells inhabit within a complex three-dimensional (3D) extracellular matrix that provides physical and chemical signals to regulate the cell fate. Cultured cells in Petri dishes and tissue culture flasks (2D) receive completely different environmental cues compared to natural tissues, causing radical alterations in cell morphology and function. Three-dimensional culture models have been able to revolutionize biomedical applications by better emulating natural tissues. However, sample handling and high-throughput screening can be challenging with 3D cell culture. Moreover, most 3D matrices are unable to quantify intracellular mechanics due to their structurally undefined surface characteristics. Therefore, highly structured surfaces (2½D) comprising various micro- and nano-patterns were introduced to address these limitations. The topographical substrates have also been shown to retain in vivo cell functionalities, such as proliferative capacity. Here, we review recent advancements in modulation of surface patterns that have been able to control cell adhesion in two or three dimensions, and their impacts on the cell behavior. Finally, we provide a comparison between 2D, 2½D and 3D systems and present several clinical applications of non-planar substrates.

The evolution of construction waste sorting on-site

Abstract: Construction waste comprises inert (e.g., sand, bricks, and concrete) and non-inert materials (e.g., bamboo, plastics, glass, wood, and paper). In Hong Kong, the inert portion can be deposited at public filling areas for land reclamation while the non-inert portion is disposed of at landfills. However, construction waste is usually a mixture of both inert and non-inert materials and thus a segregation of the two portions is of paramount importance for effective waste minimization. Previous studies have revealed that construction contractors in Hong Kong were unwilling to carry out on-site construction waste sorting (CWS) even though it has numerous advantages. After a decade, the situation should have changed, particularly given the promulgation of a waste charging scheme in 2006 imposing levies on different methods of construction waste disposal. This study thus aims at ascertaining the state-of-the-art on-site CWS practices in Hong Kong, with a particular interest in its evolution over the past ten years. Data was collected through case studies of six construction sites where a hybrid research method included a literature review, non-participant observations, and interviews. It was found that construction waste management (CWM) regulations have significantly enhanced on-site CWS in Hong Kong. Site space and project stakeholders’ attitudes are still regarded as the most critical factors but labor and cost are no longer of major concerns in undertaking on-site CWS. Instead, a market for recyclables and an awareness of the profound environmental benefits are now perceived as being of major importance in these practices. Findings from the study can be used to review the effectiveness of current on-site CWS in Hong Kong, and through benchmarking they can also be used to develop good CWS practices in other economies.