Failure analysis method for enhancing circularity through systems perspective

Recently, a circular economy has attracted global attention as an approach for addressing material security and resource-efficiency issues. As our societies shift toward a circular economy, manufacturers need to not only produce environmentally conscious products but to also realize reliable systems that will ensure the closure of the loops of the products, components, and materials. To do so, early-stage design is crucial to effectively and efficiently detect possible failures and then take adequate countermeasures against them. Although a few methods of failure analysis have been proposed to address environmental issues, these methods have failed to consider the cause–effect relationships among failures. This will hinder manufacturers from identifying core problems that should be addressed in a given system. Therefore, this study extends failure mode and effect analysis, which is an engineering technique used to address potential failures, by addressing the entire system reliability in relation to circularity. As a result of a case study of a manufacturer aiming to increase circularity with their products on the market, we revealed that the proposed method is useful in the early stage of design to (a) identify failure modes where effects are largely given to or received from other failures, (b) develop countermeasures effectively by addressing root causes of failures, and (c) find an opportunity to collaborate with external actors

Student Grade Evaluation, Survey Feedback, and Lessons Learned during the COVID-19 Pandemic: A Comparative Study of Virtual vs. In-Person Offering of a Freshman-Level General Chemistry II Course in Summer at Xavier University of Louisiana

A primary motivation for this study was to compare student perceptions and performance within a virtual learning environment to the traditional in-person learning experience for the General Chemistry II course taught during a 5-week summer session at Xavier University of Louisiana, a minority serving institution. The authors present quantitative and qualitative analyses including the comparison of student performance on exams during the COVID-19 remote learning experience with exam performance over a 3-year period of conventional in-person instruction. In this article, student grades, survey feedback, and learning outcomes are outlined. This study was performed to assist the faculty in improving and enriching the course content and its delivery, as they coped with the transition to a virtual learning environment imposed by the COVID-19 pandemic

Student Grade Evaluation, Survey Feedback, and Lessons Learned during the COVID-19 Pandemic: A Comparative Study of Virtual vs. In-Person Offering of a Freshman-Level General Chemistry II Course in Summer at Xavier University of Louisiana

A primary motivation for this study was to compare student perceptions and performance within a virtual learning environment to the traditional in-person learning experience for the General Chemistry II course taught during a 5-week summer session at Xavier University of Louisiana, a minority serving institution. The authors present quantitative and qualitative analyses including the comparison of student performance on exams during the COVID-19 remote learning experience with exam performance over a 3-year period of conventional in-person instruction. In this article, student grades, survey feedback, and learning outcomes are outlined. This study was performed to assist the faculty in improving and enriching the course content and its delivery, as they coped with the transition to a virtual learning environment imposed by the COVID-19 pandemic

CFD modeling of the building integrated with a novel design of a one-sided wind-catcher with water spray: Focus on thermal comfort

The rising energy demand for buildings has enhanced public awareness of sustainable energy sources and technologies. In particular, natural ventilation systems such as wind-catchers have attracted considerable new attention. A new wind-catcher design with single-stage direct-air evaporative cooling was proposed for indoor air conditioning. An Eulerian-Lagrangian approach employing the Realizable k-ε model was utilized to conduct the CFD simulations. Furthermore, the effects of inclining the bottom surface of the wind-catcher and installing a baffle across the flow path on the air temperature drop, water mass fraction, and air velocity distribution were studied. The inclined bottom surface led to more flow uniformity in the room compared to the conventional geometry. The baffled wind-catcher with β = 0, 30, 45, and 60° and unbaffled wind-catcher showed different flow patterns and thermal comforts. A methodology for evaluating the thermal comfort performance of evaporative cooling systems integrated into natural or passive cooling devices was also proposed based on the generated CFD results. The baffled wind-catcher with β = 60° combined with an evaporative cooling system significantly reduced the air temperature inside the building up to 17.4 °C and improved the occupants’ thermal comfort. The most suitable design for thermal comfort was also determined.</p

CFD modeling of the building integrated with a novel design of a one-sided wind-catcher with water spray: Focus on thermal comfort

The rising energy demand for buildings has enhanced public awareness of sustainable energy sources and technologies. In particular, natural ventilation systems such as wind-catchers have attracted considerable new attention. A new wind-catcher design with single-stage direct-air evaporative cooling was proposed for indoor air conditioning. An Eulerian-Lagrangian approach employing the Realizable k-ε model was utilized to conduct the CFD simulations. Furthermore, the effects of inclining the bottom surface of the wind-catcher and installing a baffle across the flow path on the air temperature drop, water mass fraction, and air velocity distribution were studied. The inclined bottom surface led to more flow uniformity in the room compared to the conventional geometry. The baffled wind-catcher with β = 0, 30, 45, and 60° and unbaffled wind-catcher showed different flow patterns and thermal comforts. A methodology for evaluating the thermal comfort performance of evaporative cooling systems integrated into natural or passive cooling devices was also proposed based on the generated CFD results. The baffled wind-catcher with β = 60° combined with an evaporative cooling system significantly reduced the air temperature inside the building up to 17.4 °C and improved the occupants’ thermal comfort. The most suitable design for thermal comfort was also determined.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Process and Energ