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
The goal of this study was to develop an automated monitoring system for the detection of pigs’ bodies, heads and tails. The aim in the first part of the study was to recognize individual pigs (in lying and standing positions) in groups and their body parts (head/ears, and tail) by using machine learning algorithms (feature pyramid network). In the second part of the study, the goal was to improve the detection of tail posture (tail straight and curled) during activity (standing/moving around) by the use of neural network analysis (YOLOv4). Our dataset (n = 583 images, 7579 pig posture) was annotated in Labelbox from 2D video recordings of groups (n = 12–15) of weaned pigs. The model recognized each individual pig’s body with a precision of 96% related to threshold intersection over union (IoU), whilst the precision for tails was 77% and for heads this was 66%, thereby already achieving human-level precision. The precision of pig detection in groups was the highest, while head and tail detection precision were lower. As the first study was relatively time-consuming, in the second part of the study, we performed a YOLOv4 neural network analysis using 30 annotated images of our dataset for detecting straight and curled tails. With this model, we were able to recognize tail postures with a high level of precision (90%)
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Community-dwelling stroke survivors tend to become less physically active over time. There is no ‘gold standard’ to measure walking activity in this population. Assessment of walking activity generally involves subjective or observer-rated instruments. Objective measuring with an activity monitor, however, gives more insight into actual walking activity. Although several activity monitors have been used in stroke patients, none of these include feedback about the actual walking activity. FESTA (FEedback to Stimulate Activity) determines number of steps, number of walking bouts, covered distance and ambulatory activity profiles over time and also provides feedback about the walking activity to the user and the therapist.
De koraalriffen van de Caribisch Nederlandse eilanden St. Eustatius en Saba zijn van groot ecologisch en economisch belang. Door een opeenstapeling van bedreigingen is de hoeveelheid driedimensionale structuur op het rif afgenomen en zijn herbivore sleutelsoorten verdwenen. Het rif wordt overwoekerd met algen, die nieuwe koraalaanwas bemoeilijken. Lokale natuurbeheerorganisaties STENAPA en SCF willen artificiële riffen inzetten, om het ecosysteem door middel van “Building with Nature” te herstellen. Artificiële riffen worden wereldwijd in toenemende mate gebruikt, maar de doeltreffendheid hangt in sterke mate af van hoe er rekening is gehouden met de lokale omstandigheden en doelstellingen. Als de riffen goed functioneren kunnen sleutelsoorten herstellen en kan koraal zich weer vestigen. De natuurbeheerorganisaties willen weten hoe artificiële riffen optimaal bij kunnen dragen aan het herstel van het koraalrif ecosysteem bij St. Eustatius en op de Saba bank. Van Hall Larenstein, STENAPA, SCF, IMARES, CNSI en Golden Rock Dive Centre werken samen in het AROSSTA (Artificial Reefs on Saba and Statia) project om deze vraag te beantwoorden. Hiervoor worden verschillende soorten artificiële riffen gebouwd van lokaal natuursteen en van veelgebruikte “reef balls”. De functionaliteit van de verschillende soorten artificiële riffen wordt bepaald door gedurende 1,5 jaar de vestiging van zee-egels, vissen en koraal te onderzoeken. Na afloop van dit project zal duidelijk zijn welk type artificieel rif het meest geschikt is voor beide onderzoeklocaties. Daarnaast is bekend wat het effect is van het gebruikte materiaal en het aanbrengen van extra schuilplaatsen op de functie van artificiële riffen. Tenslotte wordt inzicht gegeven in hoeverre artificiële riffen een bijdrage leveren aan het herstel van aangrenzende gebieden. Omdat het onderzoek uitgevoerd wordt op twee locaties, met contrasterende omstandigheden, zullen de resultaten van regionaal belang zijn om bestaande en toekomstige artificiële riffen optimaal te laten functioneren.
In a global effort to design better hospital buildings for people and organizations, some design principles are still surrounded by great mystery. The aim of this online study was to compare anxiety in an existing single-bed inpatient hospital room with three redesigns of this room in accordance with the principles of Golden Ratio, Feng Shui, and Evidence-Based Design.
