24 research outputs found
An Analytical Solution for the Total Heat Transfer in the Thin-Film Region of an Evaporating Meniscus
No full textWhen a liquid wets a solid wall, the extended meniscus may be divided into three regions: a non-evaporating region where liquid is adsorbed on the wall; a thin-film region where effects of long-range molecular forces (disjoining pressure) are felt; and an intrinsic meniscus region where capillary forces dominate. Among these, the thin-film region is characterized by high heat transfer rates because its small thickness results in a very low conduction resistance. In this work, a simplified model based on the augmented Young–Laplace equation is developed and an analytical solution is obtained for the total heat transfer in the thin-film region. The results are consistent with previously published numerical solutions. The present work is valid for a much wider range of fluid thermal conductivity than a previous analytical solution by Schonberg and Wayner, which is only applicable for fluids with very low conductivity. Based on the analytical expression developed, the thin-film heat transfer is found to increase with increasing disjoining pressure, and to decrease with increasing liquid viscosity
Media Attention to Science
No full textHow has media attention to science changed over the past decade? Does media attention bring scientific attention too? To answer these questions, we collected media attention statistics from Altmetric.com for over 40,000 papers published in PNAS journal in the last 13 years. Our analysis reveals that (i) Media attention to science has slowly, but steadily increased over time, (ii) Media attention doesn't necessarily translate into scientific attention (citations) and, (iii) It is non-trivial to predict the amount of media attention a paper gets from attributes such as authors, author affiliations, abstract, and title.Peer reviewe
FAULT DETECTION OF AN ELECTRO-HYDRAULIC CYLINDER USING ADAPTIVE ROBUST OBSERVERS
No full textThis paper presents the application of an Adaptive Robust Observer (ARO) to the detection of some common faults that occur in hydraulic cylinder drive units such as the lack of sufficient supply pressure, reduced hydraulic compliance and excessive leakage of the hydraulic fluid. All of these faults could contribute to the reduced performance of the system and eventual complete failure. The inherent nonlinear system dynamics, severe parametric uncertainties and model uncertainties make fault detection in hydraulic systems difficult to implement in practice. To tackle these problems, the Adaptive Robust Observer presented in this paper is designed using the nonlinear system dynamics and robust filter structures which attenuate the effect of model uncertainties to give robust estimates of the states. By using online parameter adaptation the accuracy of the state-estimate is improved. Also, by estimating the parameters only when certain persistence of excitation conditions are satisfied, bounds on parameter estimation errors can be computed which would help in setting better threshold limits on the residual signals which improves the robustness of the fault detection scheme. Simulation and experimental results on the swing-arm of a three-degree of freedom hydraulic robot arm are presented to demonstrate the effectiveness of the proposed fault detection scheme. ∗ Address all correspondence to this author
Creating an Engaging Doctoral Seminar: Ideas for Junior Faculty
No full textJunior faculty members at research universities are periodically tasked with the responsibility of running a research-based doctoral seminar course. Doctoral seminars present exciting opportunities for doctoral students and the faculty member teaching the course. On one hand, junior faculty, having graduated recently, have fresh perspectives on what it takes to successfully write and defend a dissertation that is timely, relevant, and rigorous. Junior faculty are also closely familiar with trends in the job market for academics and can guide students on how to succeed in these markets. On the other hand, junior faculty members, due to less time spent in academia and toward producing scholarly work in their respective fields, may not possess the broad understanding of the history of the discipline and vision for the future, that senior scholars develop from decades of experience. In this TREO talk, I posit that junior scholars can harness their comparative strengths to create engaging and effective doctoral seminar classrooms that complement seminars conducted by senior faculty members. I share several tools and strategies that I have found successful in my experience teaching information systems seminar courses over two different semesters titled “The Economics of Digital Platforms” and “Algorithms in Business and Society”. The core objectives of my seminar courses, irrespective of the topic, are to train students on the critical appreciation of literature in the field, and to help them transition from consumers of research to active creators. As the course progresses, I shift the emphasis from consumption to creation of research. With these objectives in mind, I developed a variety of pedagogical approaches. In a typical doctoral seminar, the instructor assigns papers which the students read during the week, and then present and discuss with other students during class, with the instructor moderating the discussion. In my seminar courses, this reading and discussing of papers is still a core component; but I also include additional components to keep students engaged in an active learning environment. I introduce and elaborate on seven pedagogical approaches. These are (1) viewing the syllabus as a living document partially co-created by students, (2) developing and expanding mind maps for literature synthesis, (3) inviting scholars for a meet-the-author series, where students get behind-the-scenes insights into the research and publication process, (4) encouraging students to pitch research ideas frequently for critical feedback, (5) hosting idea development workshops where each student is matched to a mentor based on their needs, (6) running a research oriented book club and (7) agile-writing exercises to instill discipline and consistency in writing. It is my hope that junior faculty members find some of these approaches in line with their pedagogy. For those who are already implementing versions of these ideas, it is my hope that delineating the approaches as above introduces intentionality in their efforts to create an engaged classroom
IMECE2004-61718 FAULT DETECTION OF AN ELECTRO-HYDRAULIC CYLINDER USING ADAPTIVE ROBUST OBSERVERS
No full textABSTRACT This paper presents the application of an Adaptive Robust Observer (ARO) to the detection of some common faults that occur in hydraulic cylinder drive units such as the lack of sufficient supply pressure, reduced hydraulic compliance and excessive leakage of the hydraulic fluid. All of these faults could contribute to the reduced performance of the system and eventual complete failure. The inherent nonlinear system dynamics, severe parametric uncertainties and model uncertainties make fault detection in hydraulic systems difficult to implement in practice. To tackle these problems, the Adaptive Robust Observer presented in this paper is designed using the nonlinear system dynamics and robust filter structures which attenuate the effect of model uncertainties to give robust estimates of the states. By using online parameter adaptation the accuracy of the state-estimate is improved. Also, by estimating the parameters only when certain persistence of excitation conditions are satisfied, bounds on parameter estimation errors can be computed which would help in setting better threshold limits on the residual signals which improves the robustness of the fault detection scheme. Simulation and experimental results on the swing-arm of a three-degree of freedom hydraulic robot arm are presented to demonstrate the effectiveness of the proposed fault detection scheme. * Address all correspondence to this author. Introduction Hydraulic systems are widely used in industrial applications because of their size-to-power ratio and the ability to apply large forces and torques with fast response times. Some of the application areas of hydraulic systems include electro-hydraulic positioning systems [1, 2], active suspension control Hydraulic systems have a number of characteristics that complicate the design of fault detection systems. These include the highly nonlinear dynamics of the hydraulic systems such as deadband and hysterisis existing in the control valves, nonlinear pressure/flow relations and variation in fluid volumes due to the movement of the actuato
F.R.I.D.A.Y (Female Replacement Intelligent Digital Assistant Youth) — an AI voice assistant: revolutionizing human-computer interaction
No full textF.R.I.D.A.Y. (Female Replacement Intelligent Digital Assistant Youth) is an A.I. voice assistant that revolutionizes human-computer interaction. F.R.I.D.A.Y. is an application that allows users to interact with a large language model like ChatGPT through natural speech, receive responses in a human-sounding voice, and perform custom tasks via prompt engineering.
The system leverages cutting-edge technologies, including OpenAI’s Whisper for speech- to-text conversion, the ChatGPT language model for intelligent response generation, Eleven Labs for text-to-speech with natural voices, and a React frontend. The backend utilizes FastAPI, Python, and middleware to integrate these components and manage conversation context.
F.R.I.D.A.Y. demonstrates the power of combining artificial intelligence, voice inter- faces, and prompt engineering to create a conversational A.I. assistant that can understand queries through speech and provide intelligent spoken responses tailored to user needs. This multimodal interaction opens new possibilities for natural and intuitive human-AI collaboration across diverse use cases.
The thesis details the system architecture, implementation challenges, and workflow. It outlines future extensions towards building an intelligent virtual assistant.M.S.Includes bibliographical reference
Development of an Articulating Cycling Mannequin for Wind Tunnel Testing
No full textGaining aerodynamic advantage is crucial in cycling, wherein drag force can account for 90% of resistance to a cyclist. The interaction of wind with the moving human and cycling equipment also contributes to drag. Testing equipment for aerodynamic properties in a wind tunnel is of interest to manufacturers in the sports industry. However, a protocol that needs to depend on the ability of a human to accurately recreate desired poses and movements multiple times may be cumbersome during testing. Additionally, a stationary mannequin does not accurately represent real-life cycling, where pedaling is a constant. Hence, a moving mannequin is suited for such applications. In this contribution, we demonstrate the development of a 3D printed articulating cycling mannequin. A cyclist was scanned using a structured light 3D scanner. Our goal was to develop an articulating mannequin with pedalling legs and a detachable upper-body to recreate two common cycling poses - time-trial and regular. In this contribution, we describe the full development of the mannequin in time trial pose. This approach outlines a low-cost method to developing mannequins for testing applications in sports.Applied Ergonomics and Desig
Analysis of the total heat transfer in an evaporating thin film
No full textWhen a liquid wets a solid wall, the extended meniscus may be divided into three regions: a non-evaporating region where liquid is adsorbed on the wall; a thin-film region where effects of long-range molecular forces (disjoining pressure) are felt; and an intrinsic meniscus region where capillary forces dominate. In this work, a simplified model based on the augmented Young-Laplace equation is developed and an analytical solution is obtained to more easily evaluate the total heat transfer in the thin-film region. The results are consistent with previously published numerical solutions. The present work is valid for a much wider range of fluid thermal conductivity than a previous analytical solution by Schonberg et al, which is only applicable for fluids with very low conductivity.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255392000143&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Engineering, MechanicalNanoscience & NanotechnologyPhysics, AppliedEICPCI-S(ISTP)
Estimating cycling aerodynamic performance using anthropometric measures
No full textAerodynamic drag force and projected frontal area (A) are commonly used indicators of aerodynamic cycling efficiency. This study investigated the accuracy of estimating these quantities using easy-to-acquire anthropometric and pose measures. In the first part, computational fluid dynamics (CFD) drag force calculations and A (m2) values from photogrammetry methods were compared using predicted 3D cycling models for 10 male amateur cyclists. The shape of the 3D models was predicted using anthropometric measures. Subsequently, the models were reposed from a standing to a cycling pose using joint angle data from an optical motion capture (mocap) system. In the second part, a linear regression analysis was performed to predict A using 26 anthropometric measures combined with joint angle data from two sources (optical and inertial mocap, separately). Drag calculations were strongly correlated with benchmark projected frontal area (coefficient of determination R2 = 0.72). A can accurately be predicted using anthropometric data and joint angles from optical mocap (root mean square error (RMSE) = 0.037 m2) or inertial mocap (RMSE = 0.032 m2). This study showed that aerodynamic efficiency can be predicted using anthropometric and joint angle data from commercially available, inexpensive posture tracking methods. The practical relevance for cyclists is to quantify and train posture during cycling for improving aerodynamic efficiency and hence performance.Applied Ergonomics and Desig
