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John H. Seinfeld – One of the best experts on this subject based on the ideXlab platform.

  • Unified Theory of vapor wall mass transport in teflon walled environmental chambers
    Environmental Science & Technology, 2018
    Co-Authors: Yuanlong Huang, R. Zhao, Sophia M Charan, Christopher M Kenseth, Xuan Zhang, John H. Seinfeld
    Abstract:

    Secondary organic aerosol (SOA) formation is studied in laboratory chambers, in which volatile organic compounds (VOCs) are oxidized to produce low-volatility compounds that condense into the aerosol phase. It has been established that such oxidized low-volatility compounds can partition into the chamber walls, which traditionally consist of Teflon film. Several studies exist in which the rates of uptake of individual vapor compounds to the chamber walls have been measured, but a Unified Theory capable of describing the range of experimental measurements has been lacking. Here, a two-layer model of observed short and long vapor–wall interaction time scales in Teflon-walled environmental chambers is presented and shown to be consistent with experimental data on the rate of wall deposition of more than 90 compounds. Semiempirical relationships between key parameters in the model and vapor molecular properties are derived, which can be used to predict the fate of gas-phase vapor in the chamber under dry cond…

  • Unified Theory of Vapor–Wall Mass Transport in Teflon-Walled Environmental Chambers
    Environmental Science & Technology, 2018
    Co-Authors: Yuanlong Huang, R. Zhao, Sophia M Charan, Christopher M Kenseth, Xuan Zhang, John H. Seinfeld
    Abstract:

    Secondary organic aerosol (SOA) formation is studied in laboratory chambers, in which volatile organic compounds (VOCs) are oxidized to produce low-volatility compounds that condense into the aerosol phase. It has been established that such oxidized low-volatility compounds can partition into the chamber walls, which traditionally consist of Teflon film. Several studies exist in which the rates of uptake of individual vapor compounds to the chamber walls have been measured, but a Unified Theory capable of describing the range of experimental measurements has been lacking. Here, a two-layer model of observed short and long vapor–wall interaction time scales in Teflon-walled environmental chambers is presented and shown to be consistent with experimental data on the rate of wall deposition of more than 90 compounds. Semiempirical relationships between key parameters in the model and vapor molecular properties are derived, which can be used to predict the fate of gas-phase vapor in the chamber under dry cond…

Yuanlong Huang – One of the best experts on this subject based on the ideXlab platform.

  • Unified Theory of vapor wall mass transport in teflon walled environmental chambers
    Environmental Science & Technology, 2018
    Co-Authors: Yuanlong Huang, R. Zhao, Sophia M Charan, Christopher M Kenseth, Xuan Zhang, John H. Seinfeld
    Abstract:

    Secondary organic aerosol (SOA) formation is studied in laboratory chambers, in which volatile organic compounds (VOCs) are oxidized to produce low-volatility compounds that condense into the aerosol phase. It has been established that such oxidized low-volatility compounds can partition into the chamber walls, which traditionally consist of Teflon film. Several studies exist in which the rates of uptake of individual vapor compounds to the chamber walls have been measured, but a Unified Theory capable of describing the range of experimental measurements has been lacking. Here, a two-layer model of observed short and long vapor–wall interaction time scales in Teflon-walled environmental chambers is presented and shown to be consistent with experimental data on the rate of wall deposition of more than 90 compounds. Semiempirical relationships between key parameters in the model and vapor molecular properties are derived, which can be used to predict the fate of gas-phase vapor in the chamber under dry cond…

  • Unified Theory of Vapor–Wall Mass Transport in Teflon-Walled Environmental Chambers
    Environmental Science & Technology, 2018
    Co-Authors: Yuanlong Huang, R. Zhao, Sophia M Charan, Christopher M Kenseth, Xuan Zhang, John H. Seinfeld
    Abstract:

    Secondary organic aerosol (SOA) formation is studied in laboratory chambers, in which volatile organic compounds (VOCs) are oxidized to produce low-volatility compounds that condense into the aerosol phase. It has been established that such oxidized low-volatility compounds can partition into the chamber walls, which traditionally consist of Teflon film. Several studies exist in which the rates of uptake of individual vapor compounds to the chamber walls have been measured, but a Unified Theory capable of describing the range of experimental measurements has been lacking. Here, a two-layer model of observed short and long vapor–wall interaction time scales in Teflon-walled environmental chambers is presented and shown to be consistent with experimental data on the rate of wall deposition of more than 90 compounds. Semiempirical relationships between key parameters in the model and vapor molecular properties are derived, which can be used to predict the fate of gas-phase vapor in the chamber under dry cond…

Yogesh K Dwivedi – One of the best experts on this subject based on the ideXlab platform.

  • re examining the Unified Theory of acceptance and use of technology utaut towards a revised theoretical model
    Information Systems Frontiers, 2019
    Co-Authors: Yogesh K Dwivedi, Nripendra P Rana, Anand Jeyaraj, Marc Clement, Michael D Williams
    Abstract:

    Based on a critical review of the Unified Theory of Acceptance and Use of Technology (UTAUT), this study first formalized an alternative theoretical model for explaining the acceptance and use of information system (IS) and information technology (IT) innovations. The revised theoretical model was then empirically examined using a combination of meta-analysis and structural equation modelling (MASEM) techniques. The meta-analysis was based on 1600 observations on 21 relationships coded from 162 prior studies on IS/IT acceptance and use. The SEM analysis showed that attitude: was central to behavioural intentions and usage behaviours, partially mediated the effects of exogenous constructs on behavioural intentions, and had a direct influence on usage behaviours. A number of implications for Theory and practice are derived based on the findings.

  • the Unified Theory of acceptance and use of technology utaut a literature review
    Journal of Enterprise Information Management, 2015
    Co-Authors: Michael D Williams, Nripendra P Rana, Yogesh K Dwivedi
    Abstract:

    – The purpose of this paper is to perform a systematic review of articles that have used the Unified Theory of acceptance and use of technology (UTAUT). , – The results produced in this research are based on the literature analysis of 174 existing articles on the UTAUT model. This has been performed by collecting data including demographic details, methodological details, limitations, and significance of relationships between the constructs from the available articles based on the UTAUT. , – The findings indicated that general purpose systems and specialized business systems were examined in the majority of the articles using the UTAUT. The analysis also indicated that cross-sectional approach, survey methods, and structural equation modelling analysis techniques were the most explored research methodologies whereas SPSS was found to be the largely used analysis tools. Moreover, the weight analysis of independent variables indicates that variables such as performance expectancy and behavioural intention qualified for the best predictor category. Moreover, the analysis also suggested that single subject or biased sample as the most explored limitation across all studies. , – The search activities were centered on occurrences of keywords to avoid tracing a large number of publications where these keywords might have been used as casual words in the main text. However, we acknowledge that there may be a number of studies, which lack keywords in the title, but still focus upon UTAUT in some form. , – This is the first research of its type which has extensively examined the literature on the UTAUT and provided the researchers with the accumulative knowledge about the model.

Emil Wolf – One of the best experts on this subject based on the ideXlab platform.

  • Some Applications of the Unified Theory of Coherence and Polarization of Light
    Frontiers in Optics 2010 Laser Science XXVI, 2010
    Co-Authors: Emil Wolf
    Abstract:

    The Unified Theory of coherence and polarization of light, formulated in 2003, is finding many useful applications. A review of some of them will be presented.

  • Unified Theory of coherence and polarization of random electromagnetic beams
    Frontiers in Optics, 2003
    Co-Authors: Emil Wolf
    Abstract:

    Unified Theory of coherence and polarization of random electromagnetic beams is presented. It makes it possible to determine changes which the degree of polarization, the degree of coherence and the spectrum of a random electromagnetic beam may undergo as the beam propagates in any linear medium, whether deterministic or random.

  • Unified Theory of coherence and polarization of random electromagnetic beams
    Physics Letters A, 2003
    Co-Authors: Emil Wolf
    Abstract:

    Abstract The usual treatment of polarization of randomly varying electromagnetic waves is based on the well-known Stokes parameter or, equivalently, on 2×2 coherence matrices (also called polarization matrices). Neither of them is adequate to elucidate the recently discovered changes of the state of polarization which a light beam may undergo as the beam propagates. We present a Unified Theory of coherence and polarization of random electromagnetic beams which brings out clearly the intimate relationship which exists between these two phenomena and which makes it possible to predict the changes in the state of polarization of a partially coherent electromagnetic beam on propagation. We illustrate the analysis by showing that a completely unpolarized beam may be spatially fully coherent.

Viswanath Venkatesh – One of the best experts on this subject based on the ideXlab platform.

  • going beyond intention integrating behavioral expectation into the Unified Theory of acceptance and use of technology
    Association for Information Science and Technology, 2017
    Co-Authors: Likoebe M Maruping, Viswanath Venkatesh, Hillol Bala, Susan A Brown
    Abstract:

    Research on information technology IT adoption and use, one of the most mature streams of research in the information science and information systems literature, is primarily based on the intentionality framework. Behavioral intention BI to use an IT is considered the sole proximal determinant of IT adoption and use. Recently, researchers have discussed the limitations of BI and argued that behavioral expectation BE would be a better predictor of IT use. However, without a theoretical and empirical understanding of the determinants of BE, we remain limited in our comprehension of what factors promote greater IT use in organizations. Using the Unified Theory of acceptance and use of technology as the theoretical framework, we develop a model that posits 2 determinants i.e., social influence and facilitating conditions of BE and 4 moderators i.e., gender, age, experience, and voluntariness of use of the relationship between BE and its determinants. We argue that the cognitions underlying the formation of BI and BE differ. We found strong support for the proposed model in a longitudinal field study of 321 users of a new IT. We offer theoretical and practical IT implications of our findings.

  • Unified Theory of acceptance and use of technology a synthesis and the road ahead
    , 2016
    Co-Authors: Viswanath Venkatesh, James Y. L. Thong
    Abstract:

    The Unified Theory of acceptance and use of technology (UTAUT) is a little over a decade old and has been used extensively in information systems (IS) and other fields, as the large number of citations to the original paper that introduced the Theory evidences. In this paper, we review and synthesize the IS literature on UTAUT from September 2003 until December 2014, perform a theoretical analysis of UTAUT and its extensions, and chart an agenda for research going forward. Based on Weber’s (2012) framework of Theory evaluation, we examined UTAUT and its extensions along two sets of quality dimensions; namely, the parts of a Theory and the Theory as a whole. While our review identifies many merits to UTAUT, we also found that the progress related to this Theory has hampered further theoretical development in research into technology acceptance and use. To chart an agenda for research that will enable significant future work, we analyze the theoretical contributions of UTAUT using Whetten’s (2009) notion of cross-context theorizing. Our analysis reveals several limitations that lead us to propose a multi-level framework that can serve as the theoretical foundation for future research. Specifically, this framework integrates the notion of research context and cross-context theorizing with the Theory evaluation framework to: (1) synthesize the existing UTAUT extensions across both the dimensions and the levels of the research context and (2) highlight promising research directions. We conclude with recommendations for future UTAUT-related research using the proposed framework.

  • CONSUMER ACCEPTANCE AND USE OF INFORMATION TECHNOLOGY: EXTENDING THE Unified Theory OF ACCEPTANCE AND USE OF TECHNOLOGY
    MIS Quarterly, 2012
    Co-Authors: Viswanath Venkatesh, James Y. L. Thong, Xin Xu
    Abstract:

    This paper extends the Unified Theory of acceptance and use of technology (UTAUT) to study acceptance and\r\nuse of technology in a consumer context. Our proposed UTAUT2 incorporates three constructs into UTAUT:\r\nhedonic motivation, price value, and habit. Individual differences—namely, age, gender, and experience—are\r\nhypothesized to moderate the effects of these constructs on behavioral intention and technology use. Results\r\nfrom a two-stage online survey, with technology use data collected four months after the first survey, of 1,512\r\nmobile Internet consumers supported our model. Compared to UTAUT, the extensions proposed in UTAUT2\r\nproduced a substantial improvement in the variance explained in behavioral intention (56 percent to 74\r\npercent) and technology use (40 percent to 52 percent). The theoretical and managerial implications of these\r\nresults are discussed.