An experimental realisation of steady spanwise forcing for turbulent drag reduction

We present an experimental realisation of spatial spanwise forcing in a turbulent boundary layer flow, aimed at reducing the frictional drag. The forcing is achieved by a series of spanwise running belts, running in alternating spanwise direction, thereby generating a steady spatial square-wave forcing. Stereoscopic particle image velocimetry is used to investigate the impact of actuation on the flow in terms of turbulence statistics, performance characteristics, and spanwise velocity profiles, for a waveform of $\lambda_x^+ = 401$. An extension of the classical spatial Stokes layer theory is proposed based on the linear superposition of Fourier modes to describe the non-sinusoidal boundary condition. The experimentally obtained spanwise profiles show good agreement with the extended theoretical model. In line with reported numerical studies, we confirm that a significant flow control effect can be realised with this type of forcing. The results reveal a maximum drag reduction of 26% and a maximum net power savings of 8%. In view of the limited spatial extent of the actuation surface in the current setup, the drag reduction is expected to increase further as a result of its streamwise transient. The second-order turbulence statistics are attenuated up to a wall-normal height of $y^+ \approx 100$, with a maximum streamwise stress reduction of 44% and a reduction of integral turbulence kinetic energy production of 39%

Into the light: effects of the presence of cleaning staff on customer experience

Purpose The purpose of this paper is to determine how the presence of cleaning staff affects perceptions and satisfaction of train passengers. Day-time cleaning is becoming increasingly popular in (public) service environments. It is however unknown how the presence of cleaning staff in the service environment affects perceptions and satisfaction of end-users. Design/methodology/approach Two experimental field studies were performed. Data for the first study were collected on the trajectory between the train station of Assen and the station of Groningen (N = 506) in the northern part of the Netherlands. Data for the second study were collected on the trajectory between train station “Amsterdam Amstel” and train station “Utrecht Centraal” (N = 1,113) in the central part of the Netherlands. In the experimental condition, two cleaners collected waste and performed minor cleaning activities (i.e. empty trash bins, cleaning doors and tables) during the journey. After the first study, cleaners received hospitality training and corporate uniforms. Findings The presence of cleaning staff positively influenced train passengers’ perceptions and satisfaction. Effects were stronger in the second study, after the second consecutive intervention (i.e. hospitality training, corporate uniforms). In both studies, the presence of cleaners positively influenced passengers’ perceptions of staff, cleanliness and comfort. The perception of atmosphere was only significant after the intervention. Practical implications The findings of this study allow in-house and corporate facility managers to better understand the possible effects of the presence of their cleaning staff on end-user perceptions and satisfaction. Originality/value The study’s value lies in its human centred approach by demonstrating the importance of day-time cleaning. This area of research has been largely neglected in the field of facilities and (public) services management research

Out of the shadows: influencing train passengers’ perceptions and satisfaction by increasing visibility of cleaning staff

Traditionally, most cleaning activities take place in the evening or during nighttime. In the Netherlands, day-time cleaning is becoming increasingly popular. It is however unknown how day-time cleaning affects perceptions and satisfaction of end-users. An experimental field study was conducted on trains of Netherlands Railways (NS) to determine how the presence of cleaning staff affects perceptions and satisfaction of train passengers

ISHLT consensus document on lung transplantation in patients with connective tissue disease: Part II: Cardiac, surgical, perioperative, operative, and post-operative challenges and management statements

Patients with connective tissue disease (CTD) present unique surgical, perioperative, operative, and postoperative challenges related to the often underlying severe pulmonary hypertension and right ventricular dysfunction. The International Society for Heart and Lung Transplantation-supported consensus document on lung transplantation in patients with CTD standardization addresses the surgical challenges and relevant cardiac involvement in the perioperative, operative, and postoperative management in patients with CTD.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Real-Time Assessment of Fatigue in Patients With Multiple Sclerosis: How Does It Relate to Commonly Used Self-Report Fatigue Questionnaires?

OBJECTIVES: (1) To assess real-time patterns of fatigue; (2) to assess the association between a real-time fatigue score and 3 commonly used questionnaires (Checklist Individual Strength [CIS] fatigue subscale, Modified Fatigue Impact Scale (MFIS), and Fatigue Severity Scale [FSS]); and (3) to establish factors that confound the association between the real-time fatigue score and the conventional fatigue questionnaires in patients with multiple sclerosis (MS). DESIGN: Cross-sectional study. SETTING: MS-specialized outpatient facility. PARTICIPANTS: Ambulant patients with MS (N=165) experiencing severe self-reported fatigue. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: A real-time fatigue score was assessed by sending participants 4 text messages on a particular day (How fatigued do you feel at this moment?; score range, 0-10). Latent class growth mixed modeling was used to determine diurnal patterns of fatigue. Regression analyses were used to assess the association between the mean real-time fatigue score and the CIS fatigue subscale, MFIS, and FSS. Significant associations were tested for candidate confounders (eg, disease severity, work status, sleepiness). RESULTS: Four significantly different fatigue profiles were identified by the real-time fatigue score, namely a stable high (n=79), increasing (n=57), stable low (n=16), and decreasing (n=13). The conventional questionnaires correlated poorly (r<.300) with the real-time fatigue score. The Epworth Sleepiness Scale significantly reduced the regression coefficient between the real-time fatigue score and conventional questionnaires, ranging from 15.4% to 35%. CONCLUSIONS: Perceived fatigue showed 4 different diurnal patterns in patients with MS. Severity of sleepiness is an important confounder to take into account in the assessment of fatigue