14 research outputs found
Does Who Am I as a Teacher Matter? Exploring Determinants of Teachers’ Learning Management System Adoption in Education Style
Learning management systems have the potential to revolutionize the way how teachers and students engage and communicate with each other in the education process. Exploring this potential becomes even more relevant in times of social distancing where education takes place at home. While extensive research has been conducted on the ICT- related factors influencing teachers’ technology adoption, factors based on the adopter- centric perspective remain largely unexplored. To fill this research gap, this paper develops a model which investigates the main determinants of teachers learning management system adoption, adding teachers\u27 professional identity as key determinant. Teachers’ professional identity is broken down into three sub-identities: subject matter expert, didactical and pedagogical expert. The study findings reveal a significant impact of all three sub-identities on teachers\u27 general attitudes towards digital media which in turn determines learning management system adoption. The model was validated by using survey data of 151 teachers
Understanding Users’ Perception on the Adoption of Stablecoins - The Libra Case
Stablecoins are cryptocurrencies that are pegged to either a fiat currency or some kind of government-backed security and so may benefit from more stability and reduced volatility in their value. More recently, many market players have been working towards the development of stablecoins for payment transactions on a global scale. However, as stablecoins by their nature represent an innovation within the payment environment, none already existing theory can properly explain users’ perception towards the adoption of stablecoins. This paper explores these perceptions by applying an explorative research approach yielding a seven factor groups conceptual framework model on stablecoins adoption. Based on 32 in-depth interviews this study contributes to the existing cryptocurrencies’ and stablecoins’ research by presenting a detailed outline of factors that enhance and inhibit stablecoins adoption, and by giving propositions for future research of this emerging topic
When Moms Go Online - Exploring Motives Determining Mothers\u27 Participation in Maternal Online Communities
In this study, we apply the general inductive theory approach to explore factors that motivate mothers to participate in online communities (OCs) targeting maternal audience. Forty mothers were recruited to participate in in-depth interviews. We clustered the participants based on their level of OC participation and the age of their last-born child to elaborate on the stages of maternal role attainment process. The study results reveal that mothers who undergo different stages of the maternal role attainment process differ in their maternal behavior and in their motivations to participate online. Factors related to maternal identity were identified as both motivators and inhibitors of mothers’ OCs participation. The motivation-participation-performance framework was used to elaborate and discuss these factors and their utilitarian and hedonic character. Through our consideration of the specific online user group - mothers, this article adds to both: the literature on OCs and motherhood
Application of Large Eddy Simulation to Predict Underwater Noise of Marine Propulsors. Part 1: Cavitation Dynamics
Marine propulsors are identified as the main contributor to a vessel’s underwater radiated noise as a result of tonal propeller noise and broadband emissions caused by its induced cavitation. To reduce a vessel’s signature, spectral limits are set for the propulsion industry, which can be experimentally obtained for a complete vessel at the full-scale; however, the prediction capability of the sound sources is still rudimentary at best. To adhere to the regulatory demands, more accurate numerical methods for combined turbulence and two-phase modeling for a high-quality prediction of acoustic sources of a propeller are required. Several studies have suggested implicit LES as a capable tool for propeller cavitation simulation. In the presented study, the main objective was the evaluation of the tip and hub vortex cavitating flows with implicit LES focusing on probable sound source representation. Cavitation structures for free-running propeller test cases were compared with experimental measurements. To resolve the structure of the tip vortex accurately, a priory mesh refinement was employed during the simulation in regions of high vorticity. Good visual agreement with the experiments and a fundamental investigation of the tip cavity structure confirmed the capability of the implicit LES for resolving detailed turbulent flow and cavitation structures for free-running propellers
Application of Large Eddy Simulation to Predict Underwater Noise of Marine Propulsors. Part 2: Noise Generation
Methods to predict underwater acoustics are gaining increased significance, as the propulsion industry is required to confirm noise spectrum limits, for instance in compliance with classification society rules. Propeller–ship interaction is a main contributing factor to the underwater noise emissions by a vessel, demanding improved methods for both hydrodynamic and high-quality noise prediction. Implicit large eddy simulation applying volume-of-fluid phase modeling with the Schnerr-Sauer cavitation model is confirmed to be a capable tool for propeller cavitation simulation in part 1. In this part, the near field sound pressure of the hydrodynamic solution of the finite volume method is examined. The sound level spectra for free-running propeller test cases and pressure pulses on the hull for propellers under behind ship conditions are compared with the experimental measurements. For a propeller-free running case with priory mesh refinement in regions of high vorticity to improve the tip vortex cavity representation, good agreement is reached with respect to the spectral signature. For behind ship cases without additional refinements, partial agreement was achieved for the incompressible hull pressure fluctuations. Thus, meshing strategies require improvements for this approach to be widely applicable in an industrial environment, especially for non-uniform propeller inflow
Adaptive Mesh Refinement for Trailing Vortices Generated by Propellers in Interaction with Slipstream Obstacles
The investigation of cavitating trailing vortices emerging from marine propellers is of great interest in the industry. With the help of computational fluid dynamics (CFD), studying the cavitating trailing vortices may be facilitated. However, limitations in computational power raise the necessity to execute numerical simulations as efficiently as possible. The time-efficient simulation of cavitating trailing vortices interacting with rigid bodies is especially challenging due to the continuous change of cavity locations. This study investigates the usability, capability, and practicability of automatic adaptive refinement at every calculation time step for transient Reynolds-averaged Navier–Stokes (RANS) and large eddy CFD simulations of the cavitating tip and hub vortices, utilizing the Schnerr–Sauer cavitation model, in the presence of a rudder located in the propeller slipstream and for an isolated propeller, with additional focus on the computational effort necessary for using high frequency updating adaptive mesh refinement (AMR). It is found that AMR is suitable for resolving cavities with relative motion to the propeller and in interaction with slipstream obstacles. However, the computation time is significantly increased, which renders this method useful only if a classic AMR is not possible due to geometrical limitations. Even in the cases that benefit from the automated AMR, numerical instabilities may lead to unphysical pressure fluctuations, which reduce the suitability of the method for the evaluation of underwater radiated noise
Untersuchung zur Wirksamkeit von Desinfektionsmitteln für den Einsatz in biologischen Gefahrenlagen
Evaluation of Sporicidal Disinfectants for the Disinfection of Personal Protective Equipment During Biological Hazards
A fast, effective, and safe disinfection of personal protective equipment (PPE) is vitally important for emergency forces involved in biological hazards. This study aimed to investigate a broad range of disinfectants to improve the established disinfection procedure. We analyzed the efficacy of chlorine-, peracetic acid–, and oxygen-based disinfectants against Bacillus spores on PPE. Therefore, spores of different Bacillus species were exposed to disinfectants on PPE material by using a standardized procedure covering the dried spores with disinfectants and applying mechanical distribution. Efficacy of disinfectants was quantified by determining the reduction factor (log10 levels) and number of viable spores left afterward. The chlorine-based granulate Hypochlorit CA G (2% chlorine) sufficiently inactivated Bacillus spores of risk groups 1 and 2, even with temperatures ranging from −20 to 35°C. Wofasteril® SC super (1.75% peracetic acid) achieved a reliable reduction of risk groups 1 and 2 and even fully virulent Bacillus spores by ≥5 log10 levels on PPE. With this, Hypochlorit-CA G and Wofasteril® SC super proved to be promising alternatives to the previously proven and widely used peracetic acid compound Wofasteril® (2% peracetic acid) for the disinfection of PPE when bacterial spores are known to be the contaminating agent. These results will help to improve the disinfection of PPE during biological hazards by providing new data on promising alternative compounds.Peer Reviewe