31 research outputs found
Effect of Hydrofoils’ Twist on the Lift-Drag Characteristics Based on Serial Production Sampling
Assessment of the water soluble ionic species of suspended particulate matter, collected at a coastal spot, De Haan, Belgium
Chemical characterisation of suspended particulate matter (SPM) is very useful for broadening the knowledge concerning processes which are active in the atmosphere (e.g. Lin, 2002). Continental air-masses were found to contain high levels of anthropogenic emitted species, while these levels decreased when the influence changed to an oceanic atmosphere. The high levels of NH4 +, NO3 - and non-sea-salt (NSS) SO4 2- in the fine SPM fraction of continental air-masses (0.38, 0.15μg.N.m-3 and 0.59μg.m-3, respectively) stresses the importance of secondary aerosol formation as a source for SPM. The dominant appearances of Na+, Cl-, Mg2+ and Ca2+ in coarse maritime air masses show the presence of sea-salts and soil dust in the atmosphere at the coastal region. Neutralisation ratios higher than unity (1.20-1.59) for the fine SPM fraction suggested an excess of NH4 +, which was most probably present in the form of NH4Cl due neutralisation of HCl. The latter was formed in atmospheric reactions with sea-salt particles (Kadowaki, 1977), during which HCl escapes (0.13 and 0.58% lost sea-salt chloride for winter and summer, respectively). Correlation analysis showed that warm and dry summer conditions eliminated some influence of sea-salts on atmospheric processes, that where found to be active during winter. NSS SO4 2- was the dominant S-contributor in the fine fraction (83%). During winter, a total SOR value of 0.61 was reached, while summer gave a significant lower value (0.24). These values classified the sampling-site at the Belgian coast as a combined receptor-source area, accepting pollution from the continent and its local surroundings (Shaw and Rodhe, 1982)
Composition of PM2.5 and PM1 on high and low pollution event days and its relation to indoor air quality in a home for the elderly
Many studies probing the link between air quality and health have pointed towards associations between particulate matter (PM) exposure and decreased lung function, aggravation of respiratory diseases like asthma, premature death and increased hospitalisation admissions for the elderly and individuals with cardiopulmonary diseases. Of recent, it is believed that the chemical composition and physical properties of PM may contribute significantly to these adverse health effects. As part of a Belgian Science Policy project (“Health effects of particulate matter in relation to physical–chemical characteristics and meteorology”), the chemical composition (elemental and ionic compositions) and physical properties (PM mass concentrations) of PM were investigated, indoors and outdoors of old age homes in Antwerp. The case reported here specifically relates to high versus normal/low pollution event periods. PM mass concentrations for PM1 and PM2.5 fractions were determined gravimetrically after collection via impaction. These same samples were hence analysed by EDXRF spectrometry and IC for their elemental and ionic compositions, respectively. During high pollution event days, PM mass concentrations inside the old age home reached 53 μg m− 3 and 32 μg m− 3 whilst outside concentrations were 101 μg m− 3 and 46 μg m− 3 for PM2.5 and PM1, respectively.
The sum of nss-sulphate, nitrate and ammonium, dominate the composition of PM, and contribute the most towards an increase in the PM during the episode days constituting 64% of ambient PM2.5 (52 μg m− 3) compared to 39% on non-episode days (10 μg m− 3). Other PM components, such as mineral dust, sea salt or heavy metals were found to be considerably higher during PM episodes but relatively less important. Amongst heavy metals Zn and Pb were found at the highest concentrations in both PM2.5 and PM1. Acid–base ionic balance equations were calculated and point to acidic aerosols during event days and acidic to alkaline aerosols during non-event days. No significant sources of indoor pollutants could be identified inside the old-age home as high correlations were found between outdoor and indoor PM, confirming mainly the outdoor origin of indoor air
Określanie chwilowego wzniesienia pokładu statku dla potrzeb sterowania suwnicą podczas operacji ładunkowych w portach morskich
The paper presents a proposal of a method for the computation of ship’s deck elevation at any time and location on-board. The need for such a computation results from an interaction between a ship and cargo being loaded or discharged by a gantry in port, in terms of heeling and rolling of the vessel. The main purpose of such modeling is the need for improvement of gantry control with regard to faster operations thanks to more accurate estimation of level and moment of cargo release from a gantry hook or spreader. The study may be the contribution to the development of gantry control systems in sea ports.W artykule przedstawiono propozycję metody obliczania chwilowego wzniosu pokładu statku podczas operacji ładunkowych w porcie. Potrzeba prowadzenia takich obliczeń wynika ze wzajemnego oddziaływania ładowanego ładunku na statek i odpowiednio – statku na proces załadunku. Statek doznaje bowiem zmiennego w czasie przechyłu wskutek umieszczenia na pokładzie bądź w ładowni dowolnej masy, np. kontenera. Zasadniczym celem opisywanych obliczeń jest poprawa dokładności sterowania suwnicą kontenerową poprzez wyznaczenie chwilowego poziomu pokładu w miejscu przeznaczenia każdego ładowanego kontenera i dalej – precyzyjne określenie wysokości i momentu ustawienia kontenera. Przeprowadzone badania mogą się przyczynić do rozwoju systemu sterowania suwnicami w portach morskich
New concept of power based pole slip protection for dispersed generators in smart grid environment
The paper presents a new pole slipping protection method that combines high efficiency of pole slip detection and sensitivity to many sources of potential pole slipping. To simplify the setup process the adaptive settings are calculated continuously. The new adaptive method utilizes active and reactive power measurements on machine terminals to ascertain that the synchronous machine is committed to pole slips. In doing so, it offers the capability of detecting pole slips even before it occurs (predictive features). During the method investigation the main efforts have been focused on the development of new protection techniques, which should ensure better (faster and more selective than currently known) detection of loss of synchronism in a synchronous machine. In the article a new approach to pole slipping protection and exemplary results are presented. The method has been successfully tested with utilization of data from simulation as well as signals from the laboratory of real synchronous machines
Oil spill damage: a collision scenario and financial liability estimations for the Northern Sea Route area
Elemental concentrations in aerosols at the Belgian coast versus seasons and air mass trajectories
Marine aerosols have extensively been monitored in the framework of a research project to investigate the inorganic and organic nutrient fluxes of the atmospheric nitrogen input into the North Sea. As a part of this project bulk analysis was also performed by energy dispersive X-ray fluorescence (EDXRF) on a total of 366 samples in order to provide detailed elemental composition. Samples have been clustered per campaign and differences were related to backward trajectories. Elements as Cl, Si, and S appeared to be the best tracers for coastal aerosols. Therefore they have been chosen to represent each campaign and to map the seasonal variations. It is clear that Cl is an excellent tracer for oceanic trajectories, while a less clear correlation between the soil dust components and the air mass trajectories is found
Major ionic species in size-segregated aerosols and associated gaseous pollutants at a coastal site on the Belgian North Sea
The chemical composition of airborne particulate matter (PM) was studied at a coastal region near De Haan, Belgium, during a winter–spring and a summer campaign in 2006. The major ionic components of size-segregated PM, i.e. NH4+, Na+, K+, Mg2+, Ca2+, Cl-, NO3-, and SO42-, and related gaseous pollutants (SO2, NO2, NH3, HNO2, and HNO3) were monitored on a daily basis. Air mass backwardtrajectories aided in evaluating the origin of the diurnal pollution load. This was characterised with high levels of fine secondary inorganic aerosols (NH4 +, NO3-, and non-sea-salt SO42-) for continental air masses, and sea-salts as the dominant species in coarse maritime aerosols. Seasonal variations in the level of major ionic species were explained by weather conditions and the release of dimethyl sulfide from marine regions. This species was responsible for an increased sea-salt Cl- depletion during summer (56%), causing elevated levels of HCl. Neutralisation ratios for the coarse fraction (0.6–0.8) suggested a depleted NH4+ level, while that for the fine fraction (1.1–1.3) had definitely an excess of NH4+, formed by the neutralisation of HCl. The results of factor analysis and the extent of SO2 oxidation indicated that the major ionic species originated from both local and remote sources, classifying the Belgian coastal region as a combined source–receptor area of air pollution
Atmospheric nitrogen fluxes at the Belgian coast: 2004-2006
Daily and seasonal variations in dry and wet atmospheric nitrogen fluxes have been studied during four campaigns between 2004 and 2006 at a coastal site of the Southern North Sea at De Haan (Belgium) located at coordinates of 51.1723° N and 3.0369°; E. Concentrations of inorganic N-compounds were determined in the gaseous phase, size-segregated aerosol (coarse, medium, and fine), and rainwater samples. Dissolved organic nitrogen (DON) was quantified in rainwater. The daily variations in N-fluxes of compounds were evaluated with air-mass backward trajectories, classified into the main air-masses arriving at the sampling site (i.e., continental, North Sea, and Atlantic/UK/Channel).The three, non-episodic campaigns showed broadly consistent fluxes, but during the late summer campaign exceptionally high episodic N-deposition was observed. The average dry and wet fluxes for non-episodic campaigns amounted to 2.6 and4.0mg N m-2 d-1, respectively, whereas during the episodic late summer period these fluxes were as high as 5.2 and 6.2mg N m-2 d-1, respectively. Non-episodic seasons/campaigns experienced average aerosol fluxes of 0.9-1.4 mg N m d-1. Generally, the contribution of aerosol NH4+ was more significant in the medium and fine particulate fractions than that of aerosol NO3-, whereas the latter contributed more in the coarse fraction, especially in continental air-masses. During the dry mid-summer campaign, the DON contributed considerably (~15%) to the total N-budget.Exceptionally high episodic aerosol-N inputs have been observed for the late summer campaign, with especially high deposition rates of 3.6 and 2.9 mg N m-2 d-1 for Atlantic/UK/Channel and North Sea-continental (mixed) air-masses, respectively. During this pollution episode, the flux of NH4+ was dominating in each aerosol fraction/air-mass, except for coarse continental aerosols. High deposition of gaseous-N was also observed in this campaign with an average total N-flux of 2-2.5-times higher than in other campaigns