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Dr. Siu-Kit Lau
National University of Singapore, Singapore

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0 Acoustics
0 Architectural Acoustics
0 Noise Control
0 Sound
0 Acoustics Applications

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Journal article
Published: 06 June 2021 in Sustainability
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Based on the findings from a recent study by the authors which examined factors affecting diffusion of photovoltaics (PV), while comprehensively considering the local PV and construction industry as well as characteristics of the built environment, this paper proposes a holistic strategy for PV implementation into Singapore’s built environment. It consists of (1) a multilevel mechanism framework, encompassing eleven mechanism categories of instruments and activities and (2) a general design framework including design principles, general project instructions and the main design guidelines. Relying on a survey conducted among PV experts on established mechanisms, the present study suggests that building codes (e.g., fire safety, structural safety, etc.) and initiatives and incentives related to PV/building-integrated photovoltaics (BIPV) should be the highest priority for authorities, followed by assessment of BIPV/PV properties, working toward social acceptance, conducting research projects and information exchange, and education and training activities. Considering all three pillars of sustainability, the design framework is based on the following interrelated design principles: (1) compatibility and coherence with the local context, (2) technical soundness, (3) economic viability, (4) user-centered design, (5) connecting with community and socio-cultural context, and (6) adaptability and flexibility. Despite Singapore’s scarcity of land, the established design guidelines cover a wide spectrum of solutions, including PV integration into both buildings and non-building structures. The synthesis of the two interconnected and inseparable frameworks aims to create an environment conducive to long-term widespread PV integration and stimulate the deployment of BIPV, which should help Singapore and other cities reduce their dependency on imported fossil fuels, while also making them more livable and enjoyable.

ACS Style

Vesna Kosorić; Siu-Kit Lau; Abel Tablada; Monika Bieri; André M. Nobre. A Holistic Strategy for Successful Photovoltaic (PV) Implementation into Singapore’s Built Environment. Sustainability 2021, 13, 6452 .

AMA Style

Vesna Kosorić, Siu-Kit Lau, Abel Tablada, Monika Bieri, André M. Nobre. A Holistic Strategy for Successful Photovoltaic (PV) Implementation into Singapore’s Built Environment. Sustainability. 2021; 13 (11):6452.

Chicago/Turabian Style

Vesna Kosorić; Siu-Kit Lau; Abel Tablada; Monika Bieri; André M. Nobre. 2021. "A Holistic Strategy for Successful Photovoltaic (PV) Implementation into Singapore’s Built Environment." Sustainability 13, no. 11: 6452.

Research article
Published: 29 April 2021 in Interactive Learning Environments
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Extensive research on process-oriented guided inquiry learning (POGIL) has addressed its impact on student performance but little attention has been devoted to approaches to learning and performance on delayed tests. The use of POGIL in online education must also be explored. This research concerns changes in students’ approaches to learning and their performance on delayed tests after the implementation of POGIL and demonstrates the challenges faced in implementing POGIL online. Various changes that could be made to adapt this methodology to online learning are also outlined. In this quasi-experimental exploratory mixed-method study, two cohorts in an undergraduate architecture program formed the control (n=79) and treatment (n=91) groups. The results of surveys, performance tests, and interviews showed that student performance on delayed tasks was significantly better (t=3.719, p=0.000, d=0.50) following the implementation of POGIL and that there was a higher increase in deep approaches and a lower increase in surface approaches to learning in the treatment group after its application. We also provide recommendations for overcoming these challenges using a POGIL framework with some modifications to its eight typical characteristics.

ACS Style

Noopur Joshi; Siu-Kit Lau. Effects of process-oriented guided inquiry learning on approaches to learning, long-term performance, and online learning outcomes. Interactive Learning Environments 2021, 1 -16.

AMA Style

Noopur Joshi, Siu-Kit Lau. Effects of process-oriented guided inquiry learning on approaches to learning, long-term performance, and online learning outcomes. Interactive Learning Environments. 2021; ():1-16.

Chicago/Turabian Style

Noopur Joshi; Siu-Kit Lau. 2021. "Effects of process-oriented guided inquiry learning on approaches to learning, long-term performance, and online learning outcomes." Interactive Learning Environments , no. : 1-16.

Journal article
Published: 01 March 2021 in Sustainability
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Despite the steady growth of grid-connected installed capacity in Singapore in the last decade and intensive government effort towards “solarization”, implementation of photovoltaics (PV) and especially building-integrated photovoltaics (BIPV) into the built environment has not gathered as much momentum as would have been expected given the country’s ample solar energy resource potential, strong economic fundamentals and the robust real estate sector. Based on a conducted web-survey and qualitative interviews among local professionals, this paper examines the obstacles, potentials and drivers that could facilitate and accelerate BIPV and PV façade integration, as well as needs that could encourage wider PV use. In order to define a unified strategy, aligning the stakeholders’ views, the following disputable factors are pointed out and discussed: (1) incomplete understanding of BIPV and building-applied photovoltaics (BAPV) among stakeholders, (2) costs of BIPV systems, (3) low awareness of and confidence in “integrability” of PV modules, (4) incomplete knowledge about and insufficiently investigated PV performance and (5) potential of PV façade and roof integration. Since the costs are the key identified factor for BIPV implementation, life-cycle cost (LCC) assessments of PV façade and roof integrations have been performed, which supported the search for solutions to identified problems. The performed analysis and findings present the basis for the development of a long-term holistic strategy for PV implementation in Singapore that could help the highly-urbanized, tropical resource- and land-constrained island city-state reduce the dependency on fossil fuels and achieve the climate change targets, thus promoting a more sustainable built environment.

ACS Style

Siu-Kit Lau; Vesna Kosorić; Monika Bieri; André.M. Nobre. Identification of Factors Influencing Development of Photovoltaic (PV) Implementation in Singapore. Sustainability 2021, 13, 2630 .

AMA Style

Siu-Kit Lau, Vesna Kosorić, Monika Bieri, André.M. Nobre. Identification of Factors Influencing Development of Photovoltaic (PV) Implementation in Singapore. Sustainability. 2021; 13 (5):2630.

Chicago/Turabian Style

Siu-Kit Lau; Vesna Kosorić; Monika Bieri; André.M. Nobre. 2021. "Identification of Factors Influencing Development of Photovoltaic (PV) Implementation in Singapore." Sustainability 13, no. 5: 2630.

Original article
Published: 04 January 2021 in International Journal of Art & Design Education
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Visual instruction complementing verbal lectures is known to promote learning among students. In this study, the role of visual instruction in engaging learners effectively via the simplification of technical concepts was examined. Different aspects of visualisation, such as order of presenting and dimensionality, were tested to observe their effect on students’ approach to learning and learning outcomes. In this mixed‐method quasi‐non‐experimental explanatory study, visual instruction was applied in one of the undergraduate architecture modules that teaches fundamentals of building systems, which students often find difficult to comprehend. Three key variables, including spatial cognitive ability, approach to learning and learning outcomes, were measured using statistically valid instruments along with students’ feedback and interviews. These factors were also measured for the control group that did not receive visual instruction (n = 32), to assess the effect of the intervention. When taught with visualisation, students (n = 69), showed a significant increase in deep approach to learning (e.g., deep motive: t = 2.584, p = 0.011). In interviews, students expressed a deeper interest in the subject and reported that the topic was engaging in class. Visualisation favours students with a higher spatial ability and, thus, is useful for design students who receive spatial ability training in the course. Two‐dimensional visuals must be followed and preceded by three‐dimensional visuals to provide advanced organisation and the connection of new knowledge with known organisational models to be made.

ACS Style

Siu‐Kit Lau; Noopur Joshi; Ming Fai Pang. Visual Instruction to Enhance Teaching of Technical Subject to Design Students. International Journal of Art & Design Education 2021, 40, 165 -183.

AMA Style

Siu‐Kit Lau, Noopur Joshi, Ming Fai Pang. Visual Instruction to Enhance Teaching of Technical Subject to Design Students. International Journal of Art & Design Education. 2021; 40 (1):165-183.

Chicago/Turabian Style

Siu‐Kit Lau; Noopur Joshi; Ming Fai Pang. 2021. "Visual Instruction to Enhance Teaching of Technical Subject to Design Students." International Journal of Art & Design Education 40, no. 1: 165-183.

Review
Published: 01 January 2021 in Sustainability
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A growing number of soundscape studies involving audiovisual factors have been conducted; however, their bimodal and interactive effects on indoor soundscape evaluations have not yet been thoroughly reviewed. The overarching goal of this systematic review was to develop the framework for designing sustainable indoor soundscapes by focusing on audiovisual factors and relations. A search for individual studies was conducted through three databases and search engines: Scopus, Web of Science, and PubMed. Based on the qualitative reviews of the selected thirty papers, a framework of indoor soundscape evaluation concerning visual and audiovisual indicators was proposed. Overall, the greenery factor was the most important visual variable, followed by the water features and moderating noise annoyance perceived by occupants in given indoor environments. The presence of visual information and sound-source visibility would moderate perceived noise annoyance and influence other audio-related perceptions. Furthermore, sound sources would impact multiple perceptual responses (audio, visual, cognitive, and emotional perceptions) related to the overall soundscape experiences when certain visual factors are interactively involved. The proposed framework highlights the potential use of the bimodality and interactivity of the audiovisual factors for designing indoor sound environments in more effective ways.

ACS Style

Yoshimi Hasegawa; Siu-Kit Lau. Audiovisual Bimodal and Interactive Effects for Soundscape Design of the Indoor Environments: A Systematic Review. Sustainability 2021, 13, 339 .

AMA Style

Yoshimi Hasegawa, Siu-Kit Lau. Audiovisual Bimodal and Interactive Effects for Soundscape Design of the Indoor Environments: A Systematic Review. Sustainability. 2021; 13 (1):339.

Chicago/Turabian Style

Yoshimi Hasegawa; Siu-Kit Lau. 2021. "Audiovisual Bimodal and Interactive Effects for Soundscape Design of the Indoor Environments: A Systematic Review." Sustainability 13, no. 1: 339.

Journal article
Published: 25 December 2020 in Applied Acoustics
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The paper predicted the sound reduction indices (SRIs) of plenum windows with various configurations by the surface impedance approach (SIA). Assuming that the glass panes of plenum windows are rigid, two spaces connected through a plenum window can be taken as a three-coupled space. In terms of a multiply connected space, the SIA enables to characterize the acoustical properties of each sub-space by its own descriptors – blocked pressure and surface impedance across the coupling interface surface between any two sub-spaces. With the descriptors identified, the sound radiation in the entire space can be predicted accordingly. The sound radiation due to a point source in an acoustical space consisting of a rectangular space, a plenum window and a semi-free space was successfully predicted by the approach. Providing the diffuse sound field is generated in the rectangular space, the SRIs of plenum windows could be determined with the predicted averaged sound pressure level in the diffuse source space and the predicted sound intensity level across a prescribed measuring surface in the receiver space, i.e., the semi-free space according to the standard ISO 15186–1. The SRIs of five plenum windows were studied by the SIA. The predicted results are in good agreement with the measured ones obtained in the laboratory environment, which indicates the feasibility of the SRI prediction by the SIA.

ACS Style

Liangfen Du; Siu-Kit Lau; Siew Eang Lee. Prediction of sound reduction index of plenum window by the surface impedance approach. Applied Acoustics 2020, 175, 107851 .

AMA Style

Liangfen Du, Siu-Kit Lau, Siew Eang Lee. Prediction of sound reduction index of plenum window by the surface impedance approach. Applied Acoustics. 2020; 175 ():107851.

Chicago/Turabian Style

Liangfen Du; Siu-Kit Lau; Siew Eang Lee. 2020. "Prediction of sound reduction index of plenum window by the surface impedance approach." Applied Acoustics 175, no. : 107851.

Journal article
Published: 23 October 2020 in Sustainability
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Research shows that in most cases occupants are not actively involved in the design process but only informed about the decisions already made. This paper proposes a framework for the early phases of socially sustainable renovation design of multifamily buildings enabling occupants’ active and timely involvement by defining appropriate mechanisms for participation in a structured manner. It further considers the interdependence of the social, environmental and economic aspects of renovation design and underlines the significance of their simultaneous consideration. The presented research shows the existence of significant heterogeneity, complexity and interdependence of a number of factors that need to be considered in order to adequately conceptualize sustainable building renovations. Finally, the paper discusses future directions for the development of the proposed model.

ACS Style

Kosa Golić; Vesna Kosorić; Siu-Kit Lau. A Framework for Early Stages of Socially Sustainable Renovation of Multifamily Buildings with Occupants’ Participation. Sustainability 2020, 12, 8823 .

AMA Style

Kosa Golić, Vesna Kosorić, Siu-Kit Lau. A Framework for Early Stages of Socially Sustainable Renovation of Multifamily Buildings with Occupants’ Participation. Sustainability. 2020; 12 (21):8823.

Chicago/Turabian Style

Kosa Golić; Vesna Kosorić; Siu-Kit Lau. 2020. "A Framework for Early Stages of Socially Sustainable Renovation of Multifamily Buildings with Occupants’ Participation." Sustainability 12, no. 21: 8823.

Regular article
Published: 15 July 2020 in The Asia-Pacific Education Researcher
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Unlike design studio, preparatory modules in the undergraduate Architecture course typically have a high student–teacher ratio and are conducted in a traditional lecture setting. By nature, lecture setting hinders engagement and reduces motivation, eventually lowering student learning outcomes. This study aimed to increase engagement with the content, lecturer, and among peers in a traditional lecture and consequently improve higher cognitive learning outcomes. Wi-Fi-enabled devices as clickers were used in all lectures to implement “pause and recall” with ConcepTests to increase participation and interaction. Lectures were paused every 15–20 min, and students were asked questions of higher cognitive order that required them to apply the concepts covered in an online platform that acted as clickers. For this quasi-non-experimental mixed-method study, 79 students’ approach to learning before and after the intervention, perception of using clickers, and learning outcomes were measured for a preparatory module, Environmental Systems in the undergraduate Architecture program. Learning outcomes were measured at various cognitive levels based on Bloom’s taxonomy. Students’ deep approach to learning increased at the end of the semester (Cohan’s d = 0.277 and 0.216 for deep motive and strategy, respectively). Students generally have a positive perception and those who showed a positive attitude towards using clickers achieved better scores at higher cognitive questions in the final test (rs = 0.359, p = 0.001). Students with a deep strategy approach to learning reflected increased self-evaluation (rs = 0.275, p = 0.022) and study behavior (rs = 0.263, p = 0.029) to use clickers. Clickers used to pose ‘ConcepTest’ questions to execute “pause and recall” in a large lecture class had a positive impact on student performance. Semi-structural interviews were performed to further explain the findings. Results were consistent with the generative theory of learning. The timing and design of clicker questions followed by a discussion were particularly beneficial in improving critical thinking among students.

ACS Style

Noopur Joshi; Siu-Kit Lau; Ming Fai Pang; Stephen Siu Yu Lau. Clickers in Class: Fostering Higher Cognitive Thinking Using ConcepTests in a Large Undergraduate Class. The Asia-Pacific Education Researcher 2020, 30, 375 -394.

AMA Style

Noopur Joshi, Siu-Kit Lau, Ming Fai Pang, Stephen Siu Yu Lau. Clickers in Class: Fostering Higher Cognitive Thinking Using ConcepTests in a Large Undergraduate Class. The Asia-Pacific Education Researcher. 2020; 30 (5):375-394.

Chicago/Turabian Style

Noopur Joshi; Siu-Kit Lau; Ming Fai Pang; Stephen Siu Yu Lau. 2020. "Clickers in Class: Fostering Higher Cognitive Thinking Using ConcepTests in a Large Undergraduate Class." The Asia-Pacific Education Researcher 30, no. 5: 375-394.

Short communication
Published: 10 July 2020 in Building and Environment
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The sound-proofed ventilation window (SPVW) is experimentally investigated in the present study for reducing noise transmission and supplying sufficient air for an arbitrary space. The SPVW consists of two layers of glass panes with two staggered vents and a mechanical ventilation system integrated within the cavity between the two glass panes. With the SPVW installed in a bedroom of the test-bedding facility in the NUS-CDL smart green home, the apparent sound reduction index (SRI) and air changes per hour (ACH) performed by the SPVW have been measured, under different conditions including the opened or closed vents and/or the operating or idle ventilation system. The experimental results indicate that the SPVW with the opened vents and the operating ventilation system provides an optimal solution for both noise reduction and ventilation performances among all the cases. The weighted SRI of this case is 13 dB higher than that of a conventional window with a similar open surface area, while the contributed ACH is 4 times higher.

ACS Style

Liangfen Du; Siu-Kit Lau; Siew Eang Lee; Martin Konrad Danzer. Experimental study on noise reduction and ventilation performances of sound-proofed ventilation window. Building and Environment 2020, 181, 107105 .

AMA Style

Liangfen Du, Siu-Kit Lau, Siew Eang Lee, Martin Konrad Danzer. Experimental study on noise reduction and ventilation performances of sound-proofed ventilation window. Building and Environment. 2020; 181 ():107105.

Chicago/Turabian Style

Liangfen Du; Siu-Kit Lau; Siew Eang Lee; Martin Konrad Danzer. 2020. "Experimental study on noise reduction and ventilation performances of sound-proofed ventilation window." Building and Environment 181, no. : 107105.

Review
Published: 16 April 2020 in Applied Acoustics
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The sense of sight or ‘visual’ plays a crucial role in the perception of soundscape. Since the concept of soundscape is put forward, audio-visual interaction has been incorporated in soundscape research, particularly in urban planning and noise control. The study on audio-visual interactions have not only enhanced and expanded the contents of soundscape assessment, but also helped to develop more comprehensive approaches for the recording and reproduction of audio-visual signals. This paper aims to evaluate the effects of audio-visual interactions on soundscape assessment and noise control through an extensive review of existing literatures. Methodologies of in situ surveys and laboratory experiments are summarized and discussed, which allows a classification system and conceptual framework for soundscape study and design with audio-visual interaction to be constructed. Accordingly, this framework can provide a guideline for the methodologies to be used in future audio-visual assessments of soundscapes and blueprint for how an audio-visual experiment should be designed.

ACS Style

Heng Li; Siu-Kit Lau. A review of audio-visual interaction on soundscape assessment in urban built environments. Applied Acoustics 2020, 166, 107372 .

AMA Style

Heng Li, Siu-Kit Lau. A review of audio-visual interaction on soundscape assessment in urban built environments. Applied Acoustics. 2020; 166 ():107372.

Chicago/Turabian Style

Heng Li; Siu-Kit Lau. 2020. "A review of audio-visual interaction on soundscape assessment in urban built environments." Applied Acoustics 166, no. : 107372.

Short communication
Published: 06 April 2020 in Applied Acoustics
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Objective acoustical indices and subjective speech perception of students were investigated and compared in two different classrooms before and after an acoustical treatment. The treatment in the present study refers to the installation of sound absorption materials on the ceilings in two primary school classrooms. The results showed that the reverberation time after acoustical treatment was reduced, while the early-to-late sound ratio and the speech transmission index were improved. The subjective speech intelligibility in classrooms was also enhanced. Subjective survey showed that most of the students preferred learning in the classrooms after acoustical treatment. They reported that higher concentration is because the speeches of the teachers were much clear in the treated classroom. However, subjective speech perception of the students has some discrepancies between the two classrooms. The perception of the students in Classroom A was better than that in Classroom B. Sixty-two percent (61.9%) of the students prefer to study in the classroom A after acoustical treatment, but only 46.3% of the students prefer to study in the Classroom B. Results show that exceeding low-frequency reverberation in the classroom may significantly mask speech signals and have effect on the student’s speech perception in classroom, even though the traditional criteria of RT and C50 at mid-frequencies are similar.

ACS Style

Jianxin Peng; Siu-Kit Lau; Yuezhe Zhao. Comparative study of acoustical indices and speech perception of students in two primary school classrooms with an acoustical treatment. Applied Acoustics 2020, 164, 107297 .

AMA Style

Jianxin Peng, Siu-Kit Lau, Yuezhe Zhao. Comparative study of acoustical indices and speech perception of students in two primary school classrooms with an acoustical treatment. Applied Acoustics. 2020; 164 ():107297.

Chicago/Turabian Style

Jianxin Peng; Siu-Kit Lau; Yuezhe Zhao. 2020. "Comparative study of acoustical indices and speech perception of students in two primary school classrooms with an acoustical treatment." Applied Acoustics 164, no. : 107297.

Journal article
Published: 19 March 2020 in Applied Acoustics
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The sound absorption via an absorber constructed by a vegetation layer and a metasurface substrate (MS) is numerically and experimentally investigated. By combining the vegetation and MS, high-efficiency sound absorption (>90%) can be achieved in a broader frequency range (from 0.93 kHz to 1.15 kHz). The MS subunit is composed of two 180°-twisted ellipse-shaped split tubes, which can achieve high absorption at the resonance frequency. According to the applications, the resonance absorption peak can be controlled by adjusting the length of the semi-major axis of the elliptical subunit. The acoustical properties of the vegetation layer can be described as a porous material, and its parameters in the simulation are obtained by fitting the measured sound absorption coefficients. Integrating the vegetation layer into the proposed absorber can further improve the absorptions in a wide frequency range of interest while it does not affect the resonance frequency of the MS subunit. Five different subunits are selected to form a deep-subwavelength MS array which can extend the absorption bandwidth. The broadband sound absorption of the absorber is robust under oblique incidence even at large incident angles. The proposed absorber has potential applications in acoustic engineering such as traffic and building noise control as well as green façades and green walls.

ACS Style

Xing-Feng Zhu; Siu-Kit Lau; Zhenbo Lu; Lai Fern Ow. Enhancement of sound absorption via vegetation with a metasurface substrate. Applied Acoustics 2020, 165, 107309 .

AMA Style

Xing-Feng Zhu, Siu-Kit Lau, Zhenbo Lu, Lai Fern Ow. Enhancement of sound absorption via vegetation with a metasurface substrate. Applied Acoustics. 2020; 165 ():107309.

Chicago/Turabian Style

Xing-Feng Zhu; Siu-Kit Lau; Zhenbo Lu; Lai Fern Ow. 2020. "Enhancement of sound absorption via vegetation with a metasurface substrate." Applied Acoustics 165, no. : 107309.

Journal article
Published: 11 December 2019 in Journal of Applied Physics
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Binary acoustic metasurfaces (AMs) are proposed and demonstrated with the goal of perfect anomalous reflection and refraction. The AMs require only two subunits per period, thereby greatly improving the fabrication accuracy and reducing the design process. Theoretical analysis gives the range of incident and diffracted angles for the case of only two propagating modes, one of which can be suppressed by designing the two subunits to have opposite phases, thereby achieving perfect anomalous reflection/refraction. Moreover, the reflection- and refraction-type binary AMs are realized using two types of space-coiling structures. Finite-element simulations show the realization of anomalous reflection and refraction, the energy efficiencies of which can reach almost 100%. The present work provides a simple and straightforward way to design high-efficiency and practical AMs that enable nearly ideal manipulation of reflected/transmitted waves.Binary acoustic metasurfaces (AMs) are proposed and demonstrated with the goal of perfect anomalous reflection and refraction. The AMs require only two subunits per period, thereby greatly improving the fabrication accuracy and reducing the design process. Theoretical analysis gives the range of incident and diffracted angles for the case of only two propagating modes, one of which can be suppressed by designing the two subunits to have opposite phases, thereby achieving perfect anomalous reflection/refraction. Moreover, the reflection- and refraction-type binary AMs are realized using two types of space-coiling structures. Finite-element simulations show the realization of anomalous reflection and refraction, the energy efficiencies of which can reach almost 100%. The present work provides a simple and straightforward way to design high-efficiency and practical AMs that enable nearly ideal manipulation of reflected/transmitted waves.

ACS Style

Xing-Feng Zhu; Siu-Kit Lau. Perfect anomalous reflection and refraction with binary acoustic metasurfaces. Journal of Applied Physics 2019, 126, 224504 .

AMA Style

Xing-Feng Zhu, Siu-Kit Lau. Perfect anomalous reflection and refraction with binary acoustic metasurfaces. Journal of Applied Physics. 2019; 126 (22):224504.

Chicago/Turabian Style

Xing-Feng Zhu; Siu-Kit Lau. 2019. "Perfect anomalous reflection and refraction with binary acoustic metasurfaces." Journal of Applied Physics 126, no. 22: 224504.

Letter
Published: 01 December 2019 in The Journal of the Acoustical Society of America
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To investigate the noise reduction mechanism of plenum windows, the paper experimentally studied the influence of the air-gap spacing between two glass panes, the panel thickness, and the opening size on the sound transmission loss (TL). The results show that when the half wavelength of impinged sound is smaller than the air-gap spacing, the TL can be improved by the decrement of the opening sizes and the increment of the glass thickness but varies little with changes in air-gap spacing. When the half wavelength of impinged sound is larger, the modification of the three factors makes little impact on the TL.

ACS Style

Liangfen Du; Siu-Kit Lau; Siew Eang Lee. Experimental study on sound transmission loss of plenum windows. The Journal of the Acoustical Society of America 2019, 146, EL489 -EL495.

AMA Style

Liangfen Du, Siu-Kit Lau, Siew Eang Lee. Experimental study on sound transmission loss of plenum windows. The Journal of the Acoustical Society of America. 2019; 146 (6):EL489-EL495.

Chicago/Turabian Style

Liangfen Du; Siu-Kit Lau; Siew Eang Lee. 2019. "Experimental study on sound transmission loss of plenum windows." The Journal of the Acoustical Society of America 146, no. 6: EL489-EL495.

Research article
Published: 22 August 2019 in Journal of Sound and Vibration
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Broadband absorption of the audible sound wave at low frequency has been achieved by using periodic acoustic metamaterial resonators (AMRs) embedded inside a porous layer. A single AMR embedded in a porous layer could reach perfect absorption (PA) at the resonance frequency, and it can be easily tuned by adjusting the inner radius of AMR. With four AMRs in the porous layer, a high absorption (>80%) is obtained in the frequency range from 180 Hz to 550 Hz, while the thickness of the porous layer is only 1/10 of the relevant wavelength at 300 Hz. The broadband and high absorption performances are due to the interferences of the low-frequency resonances of the AMRs and the energy trapping between the AMRs and the rigid backings. The finite element simulations are experimentally validated. Moreover, the broadband low-frequency absorption is robust under various oblique incidence even at large incident angles. The effects of the acoustic parameters of the porous layer on the absorption properties are also discussed. The absorbers should have high potential for the practical applications in buildings, aircrafts and automobiles due to their ease of fabrication, ultra-thin, and robust high-efficiency.

ACS Style

Xing-Feng Zhu; Siu-Kit Lau; Zhenbo Lu; Wonju Jeon. Broadband low-frequency sound absorption by periodic metamaterial resonators embedded in a porous layer. Journal of Sound and Vibration 2019, 461, 114922 .

AMA Style

Xing-Feng Zhu, Siu-Kit Lau, Zhenbo Lu, Wonju Jeon. Broadband low-frequency sound absorption by periodic metamaterial resonators embedded in a porous layer. Journal of Sound and Vibration. 2019; 461 ():114922.

Chicago/Turabian Style

Xing-Feng Zhu; Siu-Kit Lau; Zhenbo Lu; Wonju Jeon. 2019. "Broadband low-frequency sound absorption by periodic metamaterial resonators embedded in a porous layer." Journal of Sound and Vibration 461, no. : 114922.

Article
Published: 09 May 2019 in Applied Physics A
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We present the analytical derivation and numerical simulation for the wavefront manipulation of reflected waves at a lossy surface. It is found that the incident plane wave can be reflected in the desired direction or conversed to the trapped surface mode without parasitic scatterings by introducing acoustic energy loss at the surface. To realize the lossy inhomogeneous surface, holey-structured acoustic metamaterial arrays with decoupled reflection amplitude and phase are used. Anomalous reflection phenomena, including non-specular reflection, negative reflection, and conversion of the propagating wave into the surface wave, are achieved by modulating the decoupled amplitude and phase. Our results provide a practical and straightforward way to manipulate the reflected waves, which can also be extended to the three-dimensional wave propagation.

ACS Style

Xing-Feng Zhu; Siu-Kit Lau. Reflected wave manipulation via acoustic metamaterials with decoupled amplitude and phase. Applied Physics A 2019, 125, 392 .

AMA Style

Xing-Feng Zhu, Siu-Kit Lau. Reflected wave manipulation via acoustic metamaterials with decoupled amplitude and phase. Applied Physics A. 2019; 125 (6):392.

Chicago/Turabian Style

Xing-Feng Zhu; Siu-Kit Lau. 2019. "Reflected wave manipulation via acoustic metamaterials with decoupled amplitude and phase." Applied Physics A 125, no. 6: 392.

Journal article
Published: 01 January 2019 in Journal of Acoustics
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Plenum windows that ensure noise reduction and natural ventilation at the same time have been studied by many researchers. Without sacrificing the window transparency and ventilation, limited acoustical treatments could be implemented in the cavity between two glass panes to enhance noise reduction performance of plenum windows, and accordingly the sound insulation performance by plenum windows hits a bottleneck. Ventilation partition with a similar configuration to plenum windows and consisting of two opaque partition panels with staggered openings is proposed. The paper experimentally studies the sound transmission loss of six ventilation partitions with different acoustical treatments. The measurement results show that their sound transmission class (STC) ratings can be up to 21 STC points higher than that without any acoustical treatment, and the sound transmission losses are even higher than that of a closed single-layered partition at middle and high frequencies with respect to specific designs. The STC of the six ventilation partitions with acoustical treatments investigated in the present study is between STC 22 and STC 32, more than 11 STC points higher than that without any treatment.

ACS Style

Liangfen Du; Siu-Kit Lau; Siew Eang Lee. Experimental Study on Sound Insulation of Ventilation Partitions. Journal of Acoustics 2019, 1, 1 .

AMA Style

Liangfen Du, Siu-Kit Lau, Siew Eang Lee. Experimental Study on Sound Insulation of Ventilation Partitions. Journal of Acoustics. 2019; 1 (1):1.

Chicago/Turabian Style

Liangfen Du; Siu-Kit Lau; Siew Eang Lee. 2019. "Experimental Study on Sound Insulation of Ventilation Partitions." Journal of Acoustics 1, no. 1: 1.

Journal article
Published: 18 October 2018 in Sustainability
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Singapore’s high dependence on imported energy and food resources, and the lack of available land requires an efficient use of the built environment in order to increase energy and food autonomy. This paper proposes the concept of a productive façade (PF) system that integrates photovoltaic (PV) modules as shading devices as well as farming planters. It also outlines the design optimization process for eight PF prototypes comprising two categories of PF systems: Window façade and balcony façade, for four orientations. Five criteria functions describing the potential energy and food production as well as indoor visual and thermal performance were assessed by a parametric modelling tool. Optimal PF prototypes were subsequently obtained through the VIKOR optimization method, which selects the optimal design variants by compromising between the five criteria functions. East and West-facing façades require greater solar protection, and most façades require high-tilt angles on their shading PV panels. The optimal arrangement for vegetable planters involves two planters located relatively low with regard to the railing or window sill. Finally, the optimal façade designs were adjusted according to the availability of resources and the conditions and context of the Tropical Technologies Laboratory (T2 Lab) in Singapore where they are installed.

ACS Style

Abel Tablada; Vesna Kosorić; Huajing Huang; Ian Kevin Chaplin; Siu-Kit Lau; Chao Yuan; Stephen Siu-Yu Lau. Design Optimization of Productive Façades: Integrating Photovoltaic and Farming Systems at the Tropical Technologies Laboratory. Sustainability 2018, 10, 3762 .

AMA Style

Abel Tablada, Vesna Kosorić, Huajing Huang, Ian Kevin Chaplin, Siu-Kit Lau, Chao Yuan, Stephen Siu-Yu Lau. Design Optimization of Productive Façades: Integrating Photovoltaic and Farming Systems at the Tropical Technologies Laboratory. Sustainability. 2018; 10 (10):3762.

Chicago/Turabian Style

Abel Tablada; Vesna Kosorić; Huajing Huang; Ian Kevin Chaplin; Siu-Kit Lau; Chao Yuan; Stephen Siu-Yu Lau. 2018. "Design Optimization of Productive Façades: Integrating Photovoltaic and Farming Systems at the Tropical Technologies Laboratory." Sustainability 10, no. 10: 3762.

Journal article
Published: 01 September 2018 in Energy Procedia
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To improve the photovoltaic (PV) power generation, the temperature control measures and optimization of BIPV systems are critical, particularly in tropical weather. There are two categories of cooling mechanisms, i.e. passive and active cooling. In the present study, a simplified numerical model is set up to evaluate the effect of passive cooling of BIPV façades with various configurations, including the PV periphery openings (i.e. area ratio), behind air cavity depth, wind velocity and attack angle (0 to 90 degrees) on the cell temperature of BIPV module. A parametric study is performed. Three-dimensional computational fluid dynamics (CFD) simulation is applied to predict the cell temperatures under various BIPV façade configurations and environmental conditions. The results of the CFD model show that in the case where the areas of the top and bottom openings are equal, there is limited air ventilation at the behind air cavity. However, the BIPV surface temperature has a significant drop when the inlet opening at the bottom is enlarged, compared with that of the same area of inlet and outlet. Changing the wind attack angle from 0º to 60º has limited effect on the BIPV cell temperature, which results in a variation of less than 5 ºC. However, a dramatic temperature drop of around 15ºC is observed when the attack angle is larger than 60º. The influence of air cavity depth is studied with the fixed top and bottom opening size ratio. By varying the air cavity depth from 30 to 200 mm, a lower PV cell temperature can be achieved.

ACS Style

Siu-Kit Lau; Yong Zhao; Veronika Shabunko; Yuan Chao; Stephen Siu-Yu Lau; Abel Tablada; Thomas Reindl. Optimization and Evaluation of Naturally Ventilated BIPV Façade Design. Energy Procedia 2018, 150, 87 -93.

AMA Style

Siu-Kit Lau, Yong Zhao, Veronika Shabunko, Yuan Chao, Stephen Siu-Yu Lau, Abel Tablada, Thomas Reindl. Optimization and Evaluation of Naturally Ventilated BIPV Façade Design. Energy Procedia. 2018; 150 ():87-93.

Chicago/Turabian Style

Siu-Kit Lau; Yong Zhao; Veronika Shabunko; Yuan Chao; Stephen Siu-Yu Lau; Abel Tablada; Thomas Reindl. 2018. "Optimization and Evaluation of Naturally Ventilated BIPV Façade Design." Energy Procedia 150, no. : 87-93.

Review
Published: 01 August 2018 in Solar Energy
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Building-integrated photovoltaics (BIPVs) have come to be regarded as a promising technology that reduces the life-cycle costs of building construction and generates energy simultaneously. In this regard, photovoltaic integrated shading devices (PVSDs) constitute an important part of BIPVs and play a role in generating power by transforming the unwanted radiation and in reducing cooling energy consumption. Despite the expansion of the literature in recent years (2016–2017), a comprehensive review exploring the studies on PVSD is still lacking. To fill this research gap, a systematic review of the literature on PVSD was conducted. The current body of knowledge on PVSD is summarized, including aspects such as PVSD types, PV material, orientations, tilt angles, and research approaches. Several noteworthy conclusions are drawn based on the quantitative analysis of 43 journal papers on PVSD. The majority of the studies are South Korea-based (35.9%), followed by China, Greece, and Switzerland. In addition, the focus of the literature has been on the technical approach (76.5%), office building (73.3%), and equator-facing orientation (57.1%). Only 15 types of PVSD have hitherto been studied, with the emphasis on two types: the inclined single panel and horizontal louvres between double layers. Moreover, 21 architectural cases of PVSD in practice are presented and two obstacles to PVSD development are discussed. Suggestions for future study are made, including intensifying the focus on PVSD in countries with the significant solar source, such as Singapore and Australia; diversifying the exploration of multiple PVSD types (instead of only two types); and emphasizing multi-objective optimization studies on PVSD. The review can serve as a quick reference for future research and may find utility in providing an overview of PVSD to both industry practitioners and academicians.

ACS Style

Xiang Zhang; Siu-Kit Lau; Stephen Siu Yu Lau; Yong Zhao. Photovoltaic integrated shading devices (PVSDs): A review. Solar Energy 2018, 170, 947 -968.

AMA Style

Xiang Zhang, Siu-Kit Lau, Stephen Siu Yu Lau, Yong Zhao. Photovoltaic integrated shading devices (PVSDs): A review. Solar Energy. 2018; 170 ():947-968.

Chicago/Turabian Style

Xiang Zhang; Siu-Kit Lau; Stephen Siu Yu Lau; Yong Zhao. 2018. "Photovoltaic integrated shading devices (PVSDs): A review." Solar Energy 170, no. : 947-968.