Zoekresultaten

Wind resource characteristics and energy yield for micro wind turbines integrated on noise barriers

This paper assesses wind resource characteristics and energy yield for micro wind turbines integrated on noise barriers. An experimental set-up with sonic anemometers placed on top of the barrier in reference positions is realized. The effect on wind speed magnitude, inflow angle and turbulence intensity is analysed. The annual energy yield of a micro wind turbine is estimated and compared using data from a micro-wind turbine wind tunnel experiment and field data. Electrical energy costs are discussed as well as structural integration cost reduction and the potential energy yield could decrease costs. It was found that instantaneous wind direction towards the barrier and the height of observation play an influential role for the results. Wind speed increases in perpendicular flows while decreases in parallel flow, by +35% down to −20% from the reference. The azimuth of the noise barrier expressed in wind field rotation angles was found to be influential resulted in 50%–130% changes with respect to annual energy yield. A micro wind turbine (0.375 kW) would produce between 100 and 600 kWh annually. Finally, cost analysis with cost reductions due to integration and the energy yield changes due to the barrier, show a LCOE reduction at 60%–90% of the reference value. https://doi.org/10.1016/j.jweia.2020.104206

Performance characteristics of a micro wind turbine integrated on a noise barrier

tract Micro wind turbines can be structurally integrated on top of the solid base of noise barriers near highways. A number of performance factors were assessed with holistic experiments in wind tunnel and in the field. The wind turbines underperformed when exposed in yawed flow conditions. The theoretical cosθ theories for yaw misalignment did not always predict power correctly. Inverter losses turned out to be crucial especially in standby mode. Combination of standby losses with yawed flow losses and low wind speed regime may even result in a net power consuming turbine. The micro wind turbine control system for maintaining optimal power production underperformed in the field when comparing tip speed ratios and performance coefficients with the values recorded in the wind tunnel. The turbine was idling between 20%–30% of time as it was assessed for sites with annual average wind speeds of three to five meters per second without any power production. Finally, the field test analysis showed that inadequate yaw response could potentially lead to 18% of the losses, the inverter related losses to 8%, and control related losses to 33%. The totalized loss led to a 48% efficiency drop when compared with the ideal power production measured before the inverter. Micro wind turbine’s performance has room for optimization for application in turbulent wind conditions on top of noise barriers. https://doi.org/10.3390/en14051288

Psychological barrier and coping strategies in business transfers explored: towards a conceptual model

Letting go of the firm or “my baby” as some entrepreneurs describe their creation, leads to a certain amount of stress (Rahim 1996, Kets de Vries 1999). Dealing with stress in singular events as the transfer of a business, is hardly been subject of research (Uy et al. 2012). Improving coping strategies in business transfers for the incumbent could be of importance as statistics indicate the continued aging of owners in the European Union. Expanding the possibilities of incumbents to sell their business and move on to their next phase in their life would help to offset such negative effects to each national economy. The number of failed business transfers of viable SMEs now threatens innovative driven European economies (European Commission 2003, Van Teeffelen 2010, Stone et al. 2004). A recent study calculated that the Dutch economy suffers 20,000 unnecessary SME liquidations and approximately 10,000 failed successions per annum, with a projected economic damage of 80,000 jobs, a loss of turnover of almost € 4 billion and a destruction of assets of about € 2 billion yearly (Van Teeffelen 2012). Therefore we believe that coping strategies and psychological barriers in business transfers deserve more academic attention. Our aim is to check and add items to the list of psychological barriers and finally to relate barriers to coping styles. Therefore we engaged in a qualitative study that seeks to explain a particular issue and allows the researcher to study issues in depth and produces detailed data on a small number of individuals (Hyde 2000).

Barriers to and solutions for improving physical activity in adults during hospital stay: a mixed-methods study among healthcare professionals

PurposeTo identify healthcare professionals’ perspectives on key barriers to improving physical activity in hospitalized adult patients, and to identify solutions to overcome these barriers. Methods: We used an explanatory sequential mixed-methods study design in a Dutch university hospital. A survey exploring 39 potential barriers was completed by 15 physicians/physician assistants, 106 nurses, four nursing assistants, and four physical therapists working on surgery, internal medicine, and cardiology wards. Next, three in-depth semi-structured focus groups – comprising 30 healthcare professionals – discussed the survey findings to identify key barriers and solutions. Focus group discussions were analyzed using thematic analysis. Results: Five themes were identified that described both the key barriers and the solutions to overcome these barriers. Healthcare professionals proposed several solutions, including clarifying the definition of physical activity, empowering patients to take responsibility for physical activity, giving physical therapists or physicians a prominent role in encouraging physical activity, and changing the hospital ward to entice patients to become physically active. Conclusions: Healthcare professionals need clear guidelines, roles, and responsibilities when it comes to physical activity. They also need personalized interventions that empower patients in physical activity. Finally, hospital wards should be designed and furnished so that patients are encouraged to be active.

Barrier-belief lifestyle counseling in primary care: a randomised controlled trial of efficacy

Language Sample Analysis in Clinical Practice: Speech-Language Pathologists’ Barriers, Facilitators, and Needs

Purpose: Most speech-language pathologists (SLPs) working with children with developmental language disorder (DLD) do not perform language sample analysis (LSA) on a regular basis, although they do regard LSA as highly informative for goal setting and evaluating grammatical therapy. The primary aim of this study was to identify facilitators, barriers, and needs related to performing LSA by Dutch SLPs working with children with DLD. The secondary aim was to investigate whether a training would change the actual performance of LSA. Method: A focus group with 11 SLPs working in Dutch speech-language pathology practices was conducted. Barriers, facilitators, and needs were identified using thematic analysis and categorized using the theoretical domain framework. To address the barriers, a training was developed using software program CLAN. Changes in barriers and use of LSA were evaluated with a survey sent to participants before, directly after, and 3 months posttraining. Results: The barriers reported in the focus group were SLPs’ lack of knowledge and skills, time investment, negative beliefs about their capabilities, differences in beliefs about their professional role, and no reimbursement from health insurance companies. Posttraining survey results revealed that LSA was not performed more often in daily practice. Using CLAN was not the solution according to participating SLPs. Time investment remained a huge barrier. Conclusions: A training in performing LSA did not resolve the time investment barrier experienced by SLPs. User-friendly software, developed in codesign with SLPs might provide a solution. For the short-term, shorter samples, preferably from narrative tasks, should be considered.