96 research outputs found
Interaction of an Eulerian flue gas plume with wind turbines
The reduced availability of sites with the requisite wind resource, planning permission and public acceptance for the placement of wind turbines poses a significant challenge to future expansion of the wind energy industry. Developers increasingly wish to site large turbines in close proximity to industrial plants, but there is uncertainty amongst environmental protection agencies on how best to measure and regulate the impact that wind turbines may have on the dispersion of the gases that are often emitted into the atmosphere from such plants. Several simplified wind turbine-flue stack configurations have been simulated using the Vorticity Transport Model. This model provides a high-fidelity representation of the vortical flow structure within both the wind turbine wake and the plume, and is able to capture the re-direction and dispersion of the plume that occurs due to interaction with the wind turbine. The impingement of the plume on the wind turbine is shown to disrupt the wake structure downwind of the wind turbine, and may induce additional unsteady loading on the turbine rotor. The velocity deficit downwind of the wind turbine influences the rate at which the plume propagates downwind, and results in an increase in the concentration of plume material (which may include pollutant gas and particulates) around the wind turbine. This localized increase in plume concentration is shown to be sensitive to the thrust coefficient at which the wind turbine is operated. The results presented in this paper show that environmental protection agencies are justified in their concerns regarding the placement of wind turbines near to industrial plants, and suggests strongly that the interaction between wind turbines and gas plumes should be investigated further
Understanding the Meaning of Concepts Across Domains Through Collocation Analysis
Public administration scholarship is facing a crisis of legitimacy, as academic research is viewed as both increasingly irrelevant for practice and methodologically underdeveloped. In this study, we put forward a so-called collocation analysis approach, which is a useful tool for studying the meaning of key concepts in public administration and (re)focusing academic research agendas to salient societal problems by identifying how concepts are talked about in different domains. To illustrate our approach, we assess the meaning of red tape in academia, policy-making, and the media. Our dataset consists of 255 academic articles, 2,179 US Congressional Records, and 37,207 US newspaper articles mentioning red tape. We find that red tape has specific connotations in each domain, which limits the extent to which these domains are being bridged. Using the insights from our analysis, we develop a red tape research agenda that aims for more relevant and rigorous knowledge generation and conclude by setting out implications and ways forward for public administration research at large
Comorbidity, not patient age, is associated with impaired safety outcomes in vedolizumab- and ustekinumab-treated patients with inflammatory bowel disease-a prospective multicentre cohort study
Background: Few data are available on the effects of age and comorbidity on treatment outcomes of vedolizumab and ustekinumab in inflammatory bowel disease (IBD). Aims: To evaluate the association between age and comorbidity with safety and effectiveness outcomes of vedolizumab and ustekinumab in IBD. Methods: IBD patients initiating vedolizumab or ustekinumab in regular care were enrolled prospectively. Comorbidity prevalence was assessed using the Charlson Comorbidity Index (CCI). Association between age and CCI, both continuously assessed, with safety outcomes (any infection, hospitalisation, adverse events) during treatment, and effectiveness outcomes (clinical response and remission, corticosteroid-free remission, clinical remission combined with biochemical remission) after 52 weeks of treatment were evaluated. Multivariable logistic regression was used to adjust for confounders. Results: We included 203 vedolizumab- and 207 ustekinumab-treated IBD patients, mean age 42.2 (SD 16.0) and 41.6 (SD 14.4). Median treatment duration 54.0 (IQR 19.9-104.0) and 48.4 (IQR 24.4-55.1) weeks, median follow-up time 104.0 (IQR 103.1-104.0) and 52.0 weeks (IQR 49.3-100.4). On vedolizumab, CCI associated independently with any infection (OR 1.387, 95% CI 1.022-1.883, P = 0.036) and hospitalisation (OR 1.586, 95% CI 1.127-2.231, P = 0.008). On ustekinumab, CCI associated independently with hospitalisation (OR 1.621, 95% CI 1.034-2.541, P = 0.035). CCI was not associated with effectiveness, and age was not associated with any outcomes. Conclusions: Comorbidity - but not age - is associated with an increased risk of hospitalisations on either treatment, and with any infection on vedolizumab. This underlines the importance of comorbidity assessment and safety monitoring of IBD patients
Entrepreneurs’ age, institutions, and social value creation goals: a multi-country study
This study explores the relationship between an entrepreneur's age and his/her social value creation goals. Building on the lifespan developmental psychology literature and institutional theory, we hypothesize a U-shaped relationship between entrepreneurs’ age and their choice to create social value through their ventures, such that younger and older entrepreneurs create more social value with their businesses while middle age entrepreneurs are relatively more economically and less socially oriented with their ventures. We further hypothesize that the quality of a country’s formal institutions in terms of economic, social, and political freedom steepen the U-shaped relationship between entrepreneurs’ age and their choice to pursue social value creation as supportive institutional environments allow entrepreneurs to follow their age-based preferences. We confirm our predictions using multilevel mixed-effects linear regressions on a sample of over 15,000 entrepreneurs (aged between 18 and 64 years) in 45 countries from Global Entrepreneurship Monitor data. The findings are robust to several alternative specifications. Based on our findings, we discuss implications for theory and practice, and we propose future research directions
Evaluation of different methods of determining the angle of attack on wind turbine blades under yawed inflow conditions
As part of the AVATAR and Mexnext projects, this study compares several methods used to derive lifting line variables from CFD simulations of the MEXICO rotor in yawed inflow. The results from six partners within the AVATAR/Mexnext consortium using five different methods of extraction were compared. Overall comparison of the induced velocities at the mid and tip parts of blade shows fairly good agreement between the tested methods, where the derived angle of attack differs within 1°, within the linear range this accounts to ˂ 10% uncertainty on the aerodynamic forces. The presented comparison shows inadequate agreement between the methods for application towards the root
User experiences with simulated cyber‑physical attacks on smart home IoT
With the Internet of Things (IoT) becoming increasingly prevalent in people’s homes, new threats to residents are emerging such as the cyber-physical attack, i.e. a cyber-attack with physical consequences. In this study, we aimed to gain insights into how people experience and respond to cyber-physical attacks to their IoT devices. We conducted a naturalistic field experiment and provided 9 Dutch and 7 UK households, totalling 18 and 13 participants respectively, with a number of smart devices for use in their home. After a period of adaptation, simulated attacks were conducted, leading to events of varying noticeability (e.g., the light going on or off once or several times). After informing people simulated attacks had occurred, the attacks were repeated one more time. User experiences were collected through interviews and analysed with thematic analyses. Four relevant themes were identified, namely (1) the awareness of and concern about privacy and security risks was rather low, (2) the simulated attacks made little impression on the participants, (3) the participants had difficulties with correctly recognizing simulated attacks, and (4) when informed about simulated attacks taking place; participants noticed more simulated attacks and presented decision rules for them (but still were not able to identify and distinguish them well—see Theme 3). The findings emphasise the need for training interventions and an intrusion detection system to increase detection of cyber-physical attacks.European Union funding: G0H6416N-FWOOPR201600970;
Engineering and Physical Sciences Research Council (EPSRC): EP/P016448/1;
NWO: 651.002.00
Evaluation of effectiveness of the PlasmaJet surgical device in the treatment of advanced stage ovarian cancer (PlaComOv-study): study protocol of a randomized controlled trial in the Netherlands
Background: The most important goal for survival benefit of advanced stage ovarian cancer is to surgically remove
all visible tumour, because complete cytoreductive surgery (CCS) has been shown to be associated with prolonged
survival.
In a remarkable number of women, CCS is very challenging. Especially in women with many small metastases on
the peritoneum and intestinal surface, conventional CCS with electrosurgery is not able to be “complete” in
removing safely all visible tumour.
In this randomized controlled trail (RCT) we investigate whether the use of the PlasmaJet Surgical Device increases
the rate of CCS, and whether this indeed leads to a longer progression free and overall survival.
The main research question is: does the use of the PlasmaJet Surgical Device in surgery for advanced stage ovarian
cancer result in an increased number of complete cytoreductive surgeries when compared with conventional
surgical techniques. Secondary study objectives are: 30-day morbidity, duration of surgery, blood loss, length of
hospitalisation, Quality of Life, disease-free survival, overall survival, percentage colostomy, cost-effectiveness.
Methods: The study design is a multicentre single-blinded superiority RCT in two university and nine non-university
hospitals in The Netherlands. Three hundred and thirty women undergoing cytoreductive surgery for advanced
stage ovarian carcinoma (FIGO Stage IIIB-IV) will be randomized into two arms: use of the PlasmaJet (intervention
group) versus the use of standard surgical instruments combined with electrocoagulation (control group). The
primary outcome is the rate of complete cytoreductive surgery in both groups.
Secondary study objectives are: 30-day morbidity, duration of surgery, blood loss, length of hospitalisation, Quality of
Life, disease-free survival, overall survival, percentage colostomy, cost-effectiveness. Quality of life will be evaluated
using validated questionnaires at baseline, at 1 and 6 months after surgery and at 1, 2, 3 and 4 years after surgery
Discussion: We hypothesize the additional value of the use of the PlasmaJet in CCS for advanced stage epithelial
ovarian cancer. More knowledge about efficacy, side effects, recurrence rates, cost effectiveness and pathology findings
after using the PlasmaJet Device is advocated. This RCT may aid in this void
Trait phenomenological control predicts experience of mirror synaesthesia and the rubber hand illusion
In hypnotic responding, expectancies arising from imaginative suggestion drive striking experiential changes (e.g., hallucinations) — which are experienced as involuntary — according to a normally distributed and stable trait ability (hypnotisability). Such experiences can be triggered by implicit suggestion and occur outside the hypnotic context. In large sample studies (of 156, 404 and 353 participants), we report substantial relationships between hypnotisability and experimental measures of experiential change in mirror-sensory synaesthesia and the rubber hand illusion comparable to relationships between hypnotisability and individual hypnosis scale items. The control of phenomenology to meet expectancies arising from perceived task requirements can account for experiential change in psychological experiments
Middle-status conformity revisited: The interplay between achieved and ascribed status
Decisions about conforming to or deviating from conventional practices in a
field is an important concern of organization and management theory. The
position that actors occupy in the status hierarchy has been shown to be an
important determinant of these decisions. The dominant hypothesis, known
as middle-status-conformity, posits that middle-status actors are more likely
to conform to conventional practices than high- and low-status actors do. We
challenge this hypothesis by revisiting its fundamental assumptions and
developing a theory where actors’ propensity to conform based on their
achieved status further depends on their ascribed status that actors inherit
from their social group. Specifically, we propose that middle-status
conformity applies only to actors who have a sense of security, based on their
high ascribed status. For actors with low ascribed status, we propose that
high-and low-status actors show greater conformity than middle-status actors.
We test our hypotheses using data from the U.S. symphony orchestras from
1918 to 1969
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