In this work, in situ measurements of the radio frequency electromagnetic field exposure have been conducted for an indoor massive MIMO 5G base station operating at 26–28 GHz. Measurements were performed at six different positions (at distances between 9.94 and 14.32 m from the base station), of which four were in line-of-sight and two were in non-line-of-sight. A comparison was performed between the measurements conducted with an omnidirectional probe and with a horn antenna, for scenarios with and without a user equipment used to actively create an antenna traffic beam from the base station towards the measurement location. A maximum exposure of 171.9 mW/m2 was measured at a distance of 9.94 m from the base station. This is below 2% of the ICNIRP reference level. Moreover, the feasibility to measure the power per resource element of the Synchronization Signal Block - which can be used to extrapolate the maximum exposure level - with a conventional spectrum analyzer was shown by comparison with a network decoder.
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Floating urbanization is a promising solution to reduce the vulnerability of cities against climate change, population growth or land scarcity. Although this type of construction introduces changes to aquatic systems, there is a lack of research studies addressing potential impacts. Water quality data collected under/near floating structures were compared with the corresponding parameters measured at the same depth at open water locations by (i) performing scans with underwater drones equipped with in situ sensors and video cameras and (ii) fixing two sets of continuous measuring in situ sensors for a period of several days/months at both positions. A total of 18 locations with different types of floating structures were considered in this study. Results show small differences in the measured parameters, such as lower dissolved oxygen concentrations or higher temperature measured underneath the floating structures. The magnitudes of these differences seem to be linked with the characteristics and type of water system. Given the wide variety and types of water bodies considered in this study, results suggest that water quality is not critically affected by the presence of the floating houses. Underwater images of biofouling and filter feeders illustrate the lively ecosystems that can emerge shortly after the construction of floating buildings.
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Stormwater runoff can contain high amounts of Potential Toxic Elements (PTE) as heavy metals. PTE can have negative and direct impact on the quality of surface waters and groundwater. The European Water Framework Directive (WFD) demands enhanced protection of the aquatic environment. As a consequence, the WFD requires municipalities and water authorities to address the emissions from drainage systems adequately and to take action when these emissions affect the quality of receiving waters together with mitigating the quantity challenges in a changing climate (floodings and drought). NBS is the most widely used method for storing stormwater and infiltrating in the Netherlands. However, there is still too little knowledge about the long-term functioning of the soil of these facilities. The research results are of great importance for all stakeholders in (inter)national cities that are involved in climate adaptation. Applying Nature-Based Solutions (NBS), Sustainable Urban Drainage Systems (SuDS) or Water Sensitive Urban Design (WSUD) are known to improve the water quality in the urban water cycle. The efficiency of NBS, such as the capability of bio swales to trap PTE, highly depends on the dimensions of the facility and on its implementation in the field [Woods Ballard, B et al, 2015]. For the determination of the removal efficiency of NBS information about stormwater quality and characteristics is essential. Acquiring the following information is strongly advised [Boogaard et al. 2014]:1. stormwater quality levels (method: stormwater quality database);2. location of NBS (method: mapping NBS in international database);3. behaviour of pollutants (method: cost effective mapping pollutants in the field). Stormwater quality contains pollutants as heavy metal in higher concentrations than water quality standards dictate. Over 500 locations with bio swales are mapped in the Netherlands which is a fraction of stormwater infiltration locations implemented in 20 years’ time. Monitoring of all these NBS would acquire high capacity and budget from the Dutch resources. This quick scan XRF mapping methodology of topsoil will indicate if the topsoil is polluted and whether the concentrations exceed national or international standards. This was only the case in one of the youngest pilots in Utrecht indicating that there are multiple factors other than age (traffic intensity, use of materials, storage volume, maintenance, run off quality, etc.). Several locations show unacceptable levels, above the national thresholds for pollutants where further research on the prediction of these levels in relation to multiple factors will be the subject of future research.The results of study are shared in 2 national workshops and valued as of great importance for all stakeholders in (inter)national cities that are involved in implementation of NBS for climate adaptation. The Dutch research results will be used to update (inter-)national guidelines for design, construction and maintenance of infiltration facilities this year. Stormwater managers are strongly advised to use this quick scan method within the first 10 years after implementation of swales to map possible pollution of the top soil and prevent pollution to spread to the groundwater in urban areas.
DOCUMENT
Nano and micro polymeric particles (NMPs) are a point of concern by environmentalists and toxicologist for the past years. Their presence has been detected in many environmental bodies and even in more recently human blood as well. One of the most common paths these particles take to enter living organisms is via water consumption. However, despite the efforts of different academic and other knowledge groups, there is no consensus about standards methods which can be used to qualifying and quantifying these particles, especially the submicrometric ones. Many different techniques have been proposed like field flow fractionation (FFF) followed by multi angle laser scattering (MALS), pyrolysis-GC and scanning electron microscopy (SEM). Additionally, the sampling collection and preparation is also considered a difficult step, as such particles are mostly present in very low concentration. Nanocatcher proposes the use of submerged drones as a sampling collection tool to monitor the presence of submicrometric polymeric particles in water bodies. The sample collections will be done using special membrane systems specially designed for the drone. After collected, the samples will be analysed using FFF+MALS, SEM and Py-GC. If proven successful, the use of submerged drones can strongly facilitate sampling and mapping of submicrometric polymeric particles in water bodies and will provide an extensive and comprehensive map of the presence of these particles in such environment.
Vezelversterkte kunststoffen (composieten) worden in veeleisende toepassingen gebruikt, zoals in tanks voor chemicaliën of als lichtgewicht constructie-delen in vliegtuigen. Voor deze toepassingen zijn de composieten optimaal ontworpen en getest, maar ze worden met het oog op veiligheid gedurende het gebruik ook regelmatig geïnspecteerd, vaak met ultrasone analyse. Het permanent kunnen monitoren van het vervormingsgedrag van het materiaal levert een voordeel op voor zowel de veiligheid als de kosten. Zo kunnen onregelmatigheden die optreden direct worden gesignaleerd. Een intensief inspectieprogramma wordt zo verlaagd in frequentie. Met high-performance rek-sensoren op een composietproduct wordt het vervormingsgedrag gemeten en met datacommunicatie kunnen dan gegevens continue worden doorgestuurd voor beoordeling elders. Zo ontstaat een ‘smart composite structure’ waarbij permanente monitoring van composiet mogelijk is. Echter kennis ontbreekt nog over de correlatie tussen vervormingsgedrag en resultaten van een ultrasone analyse. Verder is nog niet bekend hoe de high-performance rek-sensoren functioneren over een langere tijd bij heersende bedrijfsinvloeden zoals vochtinwerking, temperatuurfluctuaties en lokale belastingen. Het project richt zich op het onderzoeken van de haalbaarheid van rek-sensortechniek die geschikt is voor het langdurig continu monitoren van het vervormingsgedrag van composieten in bedrijfssituaties. Daarbij moet binnen dit project een antwoord komen wat de voorspellende waarde is van deze monitoring t.b.v. optimaliseren van in-situ preventieve inspecties met ultrasone analyses. Daarnaast moet het onderzoek tijdens dit 1-jarige onderzoek een eerste inzicht geven op het functioneren van de high-performance rek-sensoren en de elektronica in de heersende omstandigheden over langere tijd. Het Lectoraat Kunststoftechnologie verzorgt de projectleiding en het onderzoek. Het lectoraat heeft expertise op het gebied van high-performance rek-sensoren voor vervormingsmeting op composieten. De deelnemende partners hebben belang bij de resultaten van het project. Daarnaast brengen zij specifieke expertise in die met de kennis bij het lectoraat kan leiden tot succesvolle resultaten in het onderzoek.
