2,173 research outputs found
Characterization of porous materials in compressed and uncompressed conditions using a three-microphones method
No full textConventional methods to evaluate the absorption coefficient of materials use either a large reverberation room or wave guides such as standing-wave tubes or impedance tubes. These last methods have recently been extended so that other material properties such as airflow resistivity can also be evaluated using the same tubes. An advantage of the impedance tubes is that they can also be used to measure the acoustical and non-acoustical properties when the materials are under compression. The current study investigates the differences between two-microphone systems and three-microphone systems, and assess both the absorption coefficient and the flow resistivity of porous materials such as rock wool and fibreglass in both compressed and uncompressed conditions. Finally, the results of the study are discussed
The acoustic research in the Department of Architectural Science Ryerson University
No full textThe building science laboratory in the Department of Architectural Science has capabilities to conduct research activities in the field of room acoustics and noise control. Four impedance tubes, with both two-microphone and three-microphone systems, are available to evaluate the absorption coefficient as well as a number of other material properties. A scale model wind tunnel is also available for source localization experiments. Detailed finite element modelling, through COMSOL, are used to predict acoustic performance of passive silencers, Helmholtz resonators as well as sound propagation in the available wind tunnels. Similarly, aero-acoustic simulations are also possible by using the software ACTRAN. Finally, auditorium and room acoustic researches are conducted through simulations as well as through in field measurements
Special issue: Canadian acoustics cities = Édition spéciale : Acoustique canadienne des villes
No full text
Serial coalescent simulations suggest a weak genealogical relationship between Etruscans and modern Tuscans
No full textThe Etruscans, the only preclassical European population that has been genetically characterized so far, share only two haplotypes with their modern geographic counterparts, the Tuscans, who, nonetheless, appear to be their closest relatives. We modeled 10 demographic scenarios spanning the last 2,500 years and tested by
serial coalescent simulation whether any are consistent with the patterns of genetic diversity observed within and between the Etruscan and the modern Tuscan populations. Models in which the Etruscans are the direct ancestors of modern Tuscans appear compatible with the observed data only when they also include a very high mutation rate and an ancient founder effect. A better fit
was obtained when the ancient and the modern samples were extracted from two independently evolving populations, connected by little migration. Simulated and observed parameters were also similar for a scenario in which the ancient samples came from a subset, e.g., a social elite, genetically differentiated from the bulk of the Etruscan population. In principle, these results may be biased by factors such as gross and systematic errors in the ancient DNA sequences and failure to sample suitable modern individuals. If neither proves to be the case, this study strongly suggests that either the mitochondrial mutation rate is much higher than currently believed or the Etruscans left very few modern mitochondrial descendants
Three-dimensional finite element analysis of the stress distribution pattern in the design modifications of U-shaped palatal major connector
No full textBackground: The U-shaped maxillary major connector is considered to be the least-desirable design by many prosthodontists as it lacks rigidity, which is a primary requisite for a major connector. Aims and Objectives: Design modifications in the U-shaped palatal major connector are desired because it lacks rigidity. The study also aimed to determine the best design when a U-shaped palatal major connector is indicated for clinical use. Materials and Methods: The normal design and the design-modified models (modification 1, 2, 3, 4) were loaded at the functional cusps of the premolars and the molars with a magnitude of 200 N, 250 N and 300 N at angulations of 60 o and 90 o on both sides of the maxillary arch. Results for each loading were obtained as stress distribution colored images and numerical values were recorded. A three-dimensional finite element analysis study of the design-modified models was performed using two finite element softwares, namely PRO-E and IDEAS. Results: The least stress value of 7.86 Megapascals (MPa) at 200 N, 60 o was recorded for the double-thickness design, followed by design 1, which was 8.03 MPa. The least stress value for the palatal mucosa and ligament was provided by design modification 1 (0.5 mm-thick U-shaped connector, 9 mm anteroposteiorly, 14.6 mm laterally), which was 9.78 MPa and 2.98 MPa, respectively. Conclusion: The double-thickness group exhibited the least internal stress for the U-shaped major connector. However, it delivered the greatest stress to the palatal mucosa and the periodontal ligaments
Influence of tandem axle on pavement responses and weight limit equivalency
No full textThe student, Aravind Ramakrishnan, submitted this Thesis for approval on 2020-12-08 at 12:33.This Thesis was approved for publication on 2020-12-08 at 17:03.DSpace SAF Submission Ingestion Package generated from Vireo submission #16088 on 2021-03-04 at 16:20:44Currently, pavements are designed using layered elastic theory (LET), which makes it easy to obtain the responses for a given loading configuration. However, LET minimizes the influence of axle loading configurations on pavements. Axle load limits for single (20 kips) and tandem axle (34 kips) are intended to be set so that the damage they produce is the same. In other words, axles at their corresponding weight limits are considered equivalent. Because pavement layers are more complicated than a linear elastic material, LET tends to underpredict loading responses and, hence, the damage. Therefore, to understand the effect of loading configuration on asphalt concrete (AC) behavior, Actual tandem loading and flexible pavement structure were modeled using finite element. The influence a 4.5-ft spaced tandem axle on flexible pavement responses and strain recovery were qualitatively assessed. The results showed that the effect of a tandem axle was highly pronounced for vertical strain on the subgrade, followed by that on the granular base, and then finally the transverse strain at bottom of the AC. Such responses could be approximately 1.5 to 1.75 times that of the single axle model. Stress-pulse analysis suggested that a tandem axle could be simulated accurately in laboratory tests. Although stress-pulse magnitude and shape (when no overlap is observed) are known to be independent of speed, loading-pulse duration can be calculated to identify the rest period. Similarly, domain analysis suggested that damage potential was affected by temperature and speed, which should be considered in platoon designs. Transfer functions from Mechanistic Empirical Pavement Design Guide (MEPDG) were used to compute pavement damage. Tandem axle (34 kips) and single axle (20 kips) were found to be inequivalent, confirming that the damage of the tandem axle was higher than single axle. For the given specific case, tandem axle weight of 30 kips was found to be equivalent to single axle (20 kips). This equivalency might be material, speed, tandem spacing, and structure dependent. Given the national goods movement, national weight limits should be applied after establishing an equivalency factor that consider pavement damage mechanistically.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2022-12-01The student, Aravind Ramakrishnan, accepted the attached license on 2020-12-08 at 12:17.Made available in DSpace on 2021-03-05T21:42:51Z (GMT). No. of bitstreams: 2
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Exploring image recognition: applying convoluted neural networks and learning to recognize safe cyclists
No full text"Today, there is a need to focus on the mobility revolution that is currently taking place. With the advent of more intelligent data gathering, there is also a growing need for using existing technology and infrastructure to achieve this goal, without incorporating expensive, complicated systems. As single-occupancy give way to shared mobility solutions, combined with regular mass transit and pedestrian-aware street infrastructure (traffic lights, crosswalks etc.), there is a large ""networked mobility system'' that has the potential to be tapped. Moreover, autonomous cars will be here soon, to add to the mix.
With statistics showing an increase in bicyclist related crashes over the last decade and an increase in bicycle-borne road users, there is a necessity for cities and autonomous vehicles to build bicycle safety into their adaptation to the ""driverless future"". This paper is an exploration into the use of a Convolutional Neural Network (CNN) based Machine Learning (ML) algorithm to identify bicycle-borne road users, who wear helmets.
We use a pre-made CNN framework-YOLO (You Only Look Once), and built around it further. After a brief proof-of-concept test on a publicly available dataset (including extraction, parsing and detection), the algorithm was modified. Some important features were added, such as identifying license plates, faces and encrypting them. Further, there is also a detailed account of using the ML capabilities that the framework is built with, and training it to identify bicycle-borne road users wearing a helmet."Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-08-01The student, Ramakrishnan Narayanan, accepted the attached license on 2017-07-21 at 13:17.The student, Ramakrishnan Narayanan, submitted this Thesis for approval on 2017-07-21 at 13:34.This Thesis was approved for publication on 2017-07-21 at 13:47.DSpace SAF Submission Ingestion Package generated from Vireo submission #11580 on 2018-03-02 at 13:03:11Made available in DSpace on 2018-03-02T20:02:40Z (GMT). No. of bitstreams: 2
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Scientometric Portrait of Nobel Laureate Venkatraman Ramakrishnan
No full textThe study presents an analysis of 165 research papers by Nobel Laureate Venkatraman Ramakrishnan published during 1977 to 2019 in the diverse field of science such as Biochemistry, Genetics and Molecular Biology, Medicine, Chemistry, Neuroscience, Immunology and Microbiology, Physics and Astronomy, Engineering and Materials Science. The highest number of publications contributed during the 2nd and 4th decade with 49 (29.70%) papers each. His paper entitles “Structure of the 30s ribosomal subunit” got maximum 1560 citations. Kelley, A. C. Was the most collaborative author and Europe was the most dominant continent collaborating with 132 papers whereas the United States was the top collaborated country with 100 (60.61%) papers. In the context of authorship pattern Triple authored papers were dominated with 34 (20.61%) papers. Among the most funding Sponsored body Agouron Institute topped the list with 23 (13.94%) papers, on the other hand, The Medical Research Council Laboratory of Molecular Biology, United Kingdom was the most contributed affiliation with 91 (55.15%) papers. In term of most preferred source and the most preferred subject of publications were Science with 23 (13.94%) and Biochemistry, Genetics and Molecular Biology with 97 (58.79%) papers respectively
Proceedings of the 28th Conference of Cement Microscopy
No full textBruce W. Berdenier (with Dawadi, S., Ramakrishnan, V,) is a contributing author, “Surface Morphology of Reactive Powder Concrete Containing Arsenic , pp. 205-226.
The annual meeting of the International Cement Microscopy Association consistently contributes new and innovative research on a variety of cement and concrete topics. The 2006 event featured 18 papers by international experts from universities, research institutes, and other organizations on topics including petrographic analysis, x-ray diffraction, sulfate investigation, fly ash analysis, and more. Published by ICMA
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