This study used a trait-state-occasion (TSO) model to isolate stable trait variance, occasion-specific state variance, and shared method related variance in a measure for leisure satisfaction in a Dutch nationally representative nine-year panel study. Findings indicate that satisfaction with leisure time is a consistently stronger indicator of overall leisure satisfaction than satisfaction with leisure activities. About half of the variance in leisure satisfaction is stable trait variance, with the remaining variance being mostly occasion-specific and to a lesser extent attributable to shared method variance and error. However, these findings depend on the age group we consider.Several socio-demographic variables relate directly to the trait aspect of leisure satisfaction. Our study underscores the importance of recognizing that over time leisure satisfaction measurements have considerable stable and more volatile elements and that one should control for shared method effects.
In the literature about web survey methodology, significant e orts have been made to understand the role of time-invariant factors (e.g. gender, education and marital status) in (non-)response mechanisms. Time-invariant factors alone, however, cannot account for most variations in (non-)responses, especially fluctuations of response rates over time. This observation inspires us to investigate the counterpart of time-invariant factors, namely time-varying factors and the potential role they play in web survey (non-)response. Specifically, we study the effects of time, weather and societal trends (derived from Google Trends data) on the daily (non-)response patterns of the 2016 and 2017 Dutch Health Surveys. Using discrete-time survival analysis, we find, among others, that weekends, holidays, pleasant weather, disease outbreaks and terrorism salience are associated with fewer responses. Furthermore, we show that using these variables alone achieves satisfactory prediction accuracy of both daily and cumulative response rates when the trained model is applied to future unseen data. This approach has the further benefit of requiring only non-personal contextual information and thus involving no privacy issues. We discuss the implications of the study for survey research and data collection.
Electrification of transportation, communication, working and living continues worldwide. Televisions, telephones, servers are an important part of everyday life. These loads and most sustainable sources as well, have one thing in common: Direct Current. The Dutch research and educational programme ‘DC – road to its full potential’ studies the impact of feeding these appliances from a DC grid. An improvement in energy efficiency is expected, other benefits are unknown and practical considerations are needed to come to a proper comparison with an AC grid. This paper starts with a brief introduction of the programme and its first stages. These stages encompass firstly the commissioning, selection and implementation of a safe and user friendly testing facility, to compare performance of domestic appliances when powered with AC and DC. Secondly, the relationship between the DC-testing facility and existing modeling and simulation assignments is explained. Thirdly, first results are discussed in a broad sense. An improved energy efficiency of 3% to 5% is already demonstrated for domestic appliances. That opens up questions for the performance of a domestic DC system as a whole. The paper then ends with proposed minor changes in the programme and guidelines for future projects. These changes encompass further studying of domestic appliances for product-development purposes, leaving less means for new and costly high-power testing facilities. Possible gains are 1) material and component savings 2) simpler and cheaper exteriors 3) stable and safe in-house infrastructure 4) whilst combined with local sustainable generation. That is the road ahead. 10.1109/DUE.2014.6827758
Water quality is under pressure worldwide and requires urgent attention according to recent reports, calling for technological development and more cost-effective solutions. One such development is the use of nanobubbels (NBs). NBs have been gaining interest in both scientific and industrial fields over the past years due to their broad applicability and unique characteristics opposed to larger bubbles used in traditional applications, e.g. dissolved air flotation and aeration. NBs is promising in water technology applications, especially in aeration, as due to their small size they provide a large air-water interface and are stable (present in the bulk) for many days. Due to that, different companies have been introducing NBs based technology in the market. The start-up company BIMCO Holland is one of them. They have developed three types of Ultra Fine Bubble (UFB)-generators to integrate in various (household) applications: I) a tap connection for water taps, II) a pipe adaptor for household appliances and III) a shower coupling. In order to prove their concept, BIMCO Holland wants to test the UFB-generators together with NHL Stenden. During these tests, the intended formation of NBs in tap water will be determined, as well as possible effects on the water quality. Additionally, potential applications will be (theoretically) explored, such as reduced water- and surfactant usage and prolonged lifetime of materials and appliances. With NanoBGen, the consortium aims to understand better the functioning of the newly developed UFB-generators. The tests are required to prove the system is (or not) related to the presence of NBs. Also, to support the company finding other applications of the UFB-generators and contribute to bringing the technology to a higher TRL.
