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Design Of Broadband Helmholtz Resonator Arrays Using The Radiation Impedance Method.

Rajendran, Vidhya; Piacsek, Andy; Méndez Echenagucia, Tomás. (2022). Design Of Broadband Helmholtz Resonator Arrays Using The Radiation Impedance Method. Journal Of The Acoustical Society Of America, 151(1), 457 – 466.

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Abstract

This paper describes the design process of a low-frequency sound absorptive panel composed of differently tuned Helmholtz resonators (HRs), considering size and fabrication constraints relevant for applications in the building sector. The paper focuses on cylindrical and spiral resonators with embedded necks that are thin and can achieve high absorption. the mutual interaction between the resonators was modeled based on the radiation impedance method and it plays a key component in enhancing the absorption performance of the array. The differential evolution search algorithm was used to design the resonators and modify their mutual interaction to derive the absorption performance of multiple HR arrays for comparison. Optimizations to the resonator configuration and the neck resistance were implemented to produce a unit panel that has a broadband absorption performance with emphasis on the low to mid frequencies and is thin and light in weight. Unit panels with dimensions of 20 cm x 20 cm , consisting of 29 cylindrical HRs designed to absorb in the 25–900 Hz frequency range, were constructed and tested in a custom-built impedance tube. The measured absorption performance of these panels is consistent with the theoretical predictions. [ABSTRACT FROM AUTHOR]; Copyright of Journal of the Acoustical Society of America is the property of American Institute of Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Keywords

Helmholtz Resonators; Differential Evolution; Search Algorithms; Radiation; Structural Optimization; Resonators; Bandpass Filters

Life-Cycle Cost and Carbon Footprint Analysis for Light-framed Residential Buildings Subjected to Tornado Hazard

Adhikari, Pramodit; Mahmoud, Hussam; Xie, Aiwen; Simonen, Kathrina; Ellingwood, Bruce. (2020). Life-Cycle Cost and Carbon Footprint Analysis for Light-framed Residential Buildings Subjected to Tornado Hazard. Journal Of Building Engineering, 32.

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Abstract

Light-frame wood building construction dominates the single-family residential home market in the United States. Such buildings are susceptible to damage from extreme winds due to hurricanes in coastal areas and tornados in the Midwest. The consequences of extreme winds on the built environment and on social and economic institutions within the community can be severe and are likely to increase in the coming decades as a result of increases in urbanization and economic development and the potential impacts of changing climate in hazard prone areas. Current building practices provide minimum standards for occupant safety and health, including structural integrity, water and sanitation, lighting, ventilation, means of egress and fire protection. However, they generally do not consider building resilience, which includes robustness and an ability to recover following extreme natural hazard events. Nor do they address sustainability, the notion that building design, construction and rehabilitation should not adversely impact the environment. In this paper, we establish a generalized cost and carbon footprint life-cycle analysis methodology for examining the benefits of different building practices for residential light-frame wood construction subjected to tornado hazards. A multiobjective approach is used to reveal tradeoffs between resilient and sustainable practices for typical residential construction. We show that when the life cycle of a typical residence is considered, a balance between resilience, sustainability and cost might be achieved in design and rehabilitation of residential building construction for tornado hazards.

Keywords

Performance; Risk; Fragility; Residential Buildings; Life-cycle Analysis; Resilience; Optimal Decisions; Sustainable Construction; Tornadoes

Evaluation of Sky Spectra and Sky Models in Daylighting Simulations

Inanici, M; Abboushi, B; Safranek, S. (2022). Evaluation of Sky Spectra and Sky Models in Daylighting Simulations. Lighting Research & Technology, 1.

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Abstract

Sky models in daylight simulations represent the luminance variation across the sky-dome for different locations, dates, times and weather conditions, but skies are typically modelled as colourless. Recent studies explore techniques for incorporating the spectral content of daylighting in simulations. This paper provides an evaluation of the existing spectral sky models in lighting simulation software. The comparisons are made between the available mathematical sky models and naturally occurring skies that were recorded using high dynamic range photography and spectrophotometric measurements. The results show that recently developed sky models present progress compared to colourless sky models, but further research is needed to accurately simulate daylight spectra. [ABSTRACT FROM AUTHOR]; Copyright of Lighting Research & Technology is the property of Sage Publications, Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Elizabeth Golden and team at united4design shortlisted for Aga Khan Award in architecture

The Aga Khan Award for Architecture (AKAA) recently announced 20 shortlisted projects for the 2022 Award cycle.  The projects will compete for a share of the US$ 1 million prize, one of the largest in architecture. The 20 shortlisted projects were selected by an independent Master Jury from a pool of 463 projects nominated for the 15th Award Cycle (2020-2022). The Aga Khan Award for Architecture was established by His Highness the Aga Khan in 1977 to identify and encourage…

College of Built Environments’ unique Inspire Fund aims to foster research momentum in underfunded pursuits college-wide. And it’s working.

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Daniel Abramson and collaborators awarded EarthLab Innovation grant for community-based research project on climate change & social justice

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Carbon Leadership Forum awarded ARPA-E grant to develop life cycle assessment tools for carbon negative buildings 

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2022 CBE Inspire Fund awardees announced

In 2021 the College of Built Environments launched the CBE Inspire Fund, designed to support CBE research activities for which a relatively small amount of support can be transformative. The second year of awards have just been announced, supporting five projects across 4 departments within the college as they address topics such as food sovereignty, anti-displacement, affordable housing, and health & wellbeing. This year’s awardees include:  Defining the New Diaspora: Where Seattle’s Black Church Congregants Are Moving and Why Rachel…