scholarly journals Estimation of ship emission rates at a major shipping lane by long path DOAS measurements

2021 ◽  
Author(s):  
Kai Krause ◽  
Folkard Wittrock ◽  
Andreas Richter ◽  
Stefan Schmitt ◽  
Denis Pöhler ◽  
...  
Keyword(s):  
Emission Factors ◽  
Emission Rates ◽  
River Elbe ◽  
Gaussian Plume ◽  
Remote Sensing Techniques ◽  
One Year ◽  
First Time ◽  
Good Agreement ◽  
Ship Emission

Abstract. Ships are an important source of SO2 and NOx, which are key parameters of air quality. Monitoring of ship emissions is usually carried out using in situ instruments on land, which depend on favourable wind conditions to transport the emitted substances to the measurement site. Remote sensing techniques such as long path DOAS (LP-DOAS) measurements can supplement those measurements, especially in unfavourable meteorological conditions. In this study one year of LP-DOAS measurements made across the river Elbe close to Hamburg (Germany) have been evaluated. Peaks (i.e. elevated concentrations) in the NO2 and SO2 time series were assigned to passing ships and a method to derive emission rates of SO2, NO2 and NOx from those measurements using a Gaussian plume model is presented. 7402 individual ship passages have been monitored and their respective NOx, SO2 and NO2 emission rates have been derived. The emission rates, coupled with the knowledge of the ship type, ship size and ship speed have been analysed. Emission rates are compared to emission factors from previous studies and show good agreement. In contrast to emission factors (in gram per kilogram fuel) the derived emission rates (in gram per second) do not need further knowledge about the fuel consumption of the ship. To our knowledge this is the first time emission rates of air pollutants from individual ships have been derived from LP-DOAS measurements.

scholarly journals Estimation of ship emission rates at a major shipping lane by long-path DOAS measurements

2021 ◽  
Vol 14 (8) ◽  
pp. 5791-5807
Author(s):  
Kai Krause ◽  
Folkard Wittrock ◽  
Andreas Richter ◽  
Stefan Schmitt ◽  
Denis Pöhler ◽  
...  
Keyword(s):  
Emission Factors ◽  
Optical Absorption Spectroscopy ◽  
Emission Rates ◽  
River Elbe ◽  
Gaussian Plume ◽  
Remote Sensing Techniques ◽  
First Time ◽  
Good Agreement ◽  
Ship Emission

Abstract. Ships are an important source of SO2 and NOx, which are key parameters of air quality. Monitoring of ship emissions is usually carried out using in situ instruments on land, which depend on favourable wind conditions to transport the emitted substances to the measurement site. Remote sensing techniques such as long-path differential optical absorption spectroscopy (LP-DOAS) measurements can supplement those measurements, especially in unfavourable meteorological conditions. In this study 1 year of LP-DOAS measurements made across the river Elbe close to Hamburg (Germany) have been evaluated. Peaks (i.e. elevated concentrations) in the NO2 and SO2 time series were assigned to passing ships, and a method to derive emission rates of SO2, NO2 and NOx from those measurements using a Gaussian plume model is presented. A total of 7402 individual ship passages have been monitored, and their respective NOx, SO2 and NO2 emission rates have been derived. The emission rates, coupled with the knowledge of the ship type, ship size and ship speed, have been analysed. Emission rates are compared to emission factors from previous studies and show good agreement. In contrast to emission factors (in grams per kilogram fuel), the derived emission rates (in grams per second) do not need further knowledge about the fuel consumption of the ship. To our knowledge this is the first time emission rates of air pollutants from individual ships have been derived from LP-DOAS measurements.

Gas Phase and Surface Reactions in Mocvd of GaAs from Triethylgallium, Trimethylgallium, and Organometallic Arsenic Precursors

1988 ◽  
Vol 131 ◽  
Author(s):  
Thomas R. Omstead ◽  
Penny M. Van Sickle ◽  
Klavs F. Jensen
Keyword(s):  
Gas Phase ◽  
Low Temperatures ◽  
Surface Reactions ◽  
Rate Data ◽  
Gas Phase Reactions ◽  
Heated Zone ◽  
Model Predictions ◽  
First Time ◽  
Good Agreement

ABSTRACTThe growth of GaAs from triethylgallium (TEG) and trimethylgallium (TMG) with tertiarybutylarsine (tBAs), triethylarsenic (TEAs), and trimethylarsenic (TMAs), has been investigated by using a reactor equipped with a recording microbalance for in situ rate measurements. Rate data show that the growth with these precursors is dominated by the formation of adduct compounds in the gas lines, by adduct related parasitic gas phase reactions in the heated zone, and by the surface reactions. A model is proposed for the competition between deposition reactions and the parasitic gas phase reactions. Model predictions are in very good agreement with experimental data for all combinations of precursors except for TEG/TMAs where extensive gallium droplet formation is observed at low temperatures. Growth of reasonable quality GaAs with Hall mobilities of 7600 cm2/Vs at 77 K using TEG and tBAs is reported for the first time.

scholarly journals A method for monitoring hydrological conditions beneath herbaceous wetlands using multi-temporal ALOS PALSAR coherence data

2015 ◽  
Vol XL-7/W4 ◽  
pp. 221-226 ◽  
Author(s):  
M. Zhang ◽  
Z. Li ◽  
B. Tian ◽  
J. Zhou ◽  
J. Zeng
Keyword(s):  
Effective Area ◽  
Interferometric Synthetic Aperture Radar ◽  
Alos Palsar ◽  
Hydrological Conditions ◽  
In Situ Data ◽  
Key Indicator ◽  
Multi Temporal ◽  
First Time ◽  
Good Agreement

Reed marshes, the world’s most widespread type of wetland vegetation, are undergoing major changes as a result of climate changes and human activities. The presence or absence of water in reed marshes has a significant impact on the whole ecosystem and remains a key indicator to identify the effective area of a wetland and help estimate the degree of degeneration. Past studies have demonstrated the use of interferometric synthetic aperture radar (InSAR) to map water-level changes for flooded reeds. However, the identification of the different hydrological states of reed marshes is often poorly understood. The analysis given in this paper shows that L-band interferometric coherence is very sensitive to the water surface conditions beneath reed marshes and so can be used as classifier. A method based on a statistical analysis of the coherence distributions for wet and dry reeds using InSAR pairs was, therefore, investigated in this study. The experimental results were validated by in-situ data and showed very good agreement. This is the first time that information about the water cover under herbaceous wetlands has been derived using interferometric coherence values. This method can also effectively and easily be applied to monitor the hydrological conditions beneath other herbaceous wetlands.

Towards operational monitoring of ship emissions using Long Path Differential Optical Absorption Spectroscopy

2020 ◽  
Author(s):  
Stefan Schmitt ◽  
Denis Pöhler ◽  
Andreas Weigelt ◽  
Folkard Wittrock ◽  
André Seyler ◽  
...  
Keyword(s):  
Air Pollution ◽  
Broad Band ◽  
Optical Absorption Spectroscopy ◽  
Traffic Density ◽  
Ship Emissions ◽  
Sulphur Compounds ◽  
River Elbe ◽  
Set Up ◽  
Ship Emission

<p>In contrast to land-based sources of air pollution, which have been regulated and reduced since several decades, NO<sub>x</sub> and SO<sub>x</sub> emissions from ships were only recently identified as significant sources of air pollution. As one consequence the sulphur content of ship fuel used within the so-called Sulphur Emission Control Areas (SECA) was recently regulated to a maximum of 0.1% (m/m) (MARPOL Annex VI). Therefore, especially monitoring the emission of sulphur compounds is of particular interest.</p><p>Within a 6-week measurement campaign in July and August of 2016, ship emissions were measured at the river Elbe in Germany, near Hamburg using the Long Path (LP)-DOAS technique. The measurements were carried out within the framework of the project MeSMarT (MEasurements of Shipping emissions in the MARine Troposphere), which investigates the influence of ship emissions on chemical processes in the atmosphere. Currently, monitoring of ship emission plumes is typically achieved by a combination of in situ trace gas monitors and meteorological sensors. In contrast to that the LP-DOAS technique is capable of simultaneously measuring signatures of multiple trace gases along an absorption path across a well-frequented waterway close to the ship exhaust-pipes and thus directly in the emission plume at a time resolution of a few seconds.</p><p>For our study, a LP-DOAS instrument was set up side by side to an in situ MeSMarT measurement station at the river Elbe at Wedel (15 km downriver of Hamburg harbour) where NO<sub>2</sub> and SO<sub>2</sub> emission signatures of a total of 5037 ship passes (of 1044 individual ships) were monitored. While the in situ method detected 16% of the ships, the LP-DOAS was able to assign emission plumes to 41% of all passing ships. With meteorology mainly limiting the in situ detection yield, the major limitation for the LP-DOAS was found to be due to the high traffic density and thus the difficulty to unambiguously assign recorded plumes to particular vessels, rather than to the sensitivity to the emission plume itself.</p><p>Based on the results of this feasibility study, we present a newly designed LP-DOAS system fulfilling the requirements for operational ship emission monitoring (robust mechanical setup, broad-band long-lifetime light source, compact sealed housing, automized alignment and data acquisition). This new system is now operated continuously to measure the ship emissions on the river Elbe.</p>

scholarly journals Expression of an acidic isoform of calponin in rat brain: western blots on one- or two-dimensional gels and immunolocalization in cultured cells

1995 ◽  
Vol 306 (1) ◽  
pp. 211-215 ◽  
Author(s):  
H Trabelsi-Terzidis ◽  
A Fattoum ◽  
A Represa ◽  
F Dessi ◽  
Y Ben-Ari ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Rat Brain ◽  
Cultured Cells ◽  
Two Dimensional ◽  
Brain Protein ◽  
Western Blots ◽  
Calmodulin Binding ◽  
First Time ◽  
Good Agreement

Calponin, an actin- and Ca(2+)-calmodulin-binding protein characterized as an inhibitory factor of the smooth-muscle actomyosin activity, has also been shown to be present in some non-muscle cells. However, there is a controversy as to whether calponin is present or not in brain. Several laboratories indicate that this protein is absent in chicken or bovine brains, while Applegate et al. [Applegate, Feng, Green and Taubman (1994) J. Biol. Chem. 269, 10683-10690] have recently reported the identification of an mRNA specific for a 36 kDa non-muscle calponin analogue in homogenates of rat brains. For the first time we demonstrate, by Western blots and in situ immunofluorescence localization using monoclonal as well as affinity-purified polyclonal antibody to gizzard calponin, that a 36-37 kDa and a 35-36 kDa calponin-like proteins are expressed respectively in pig and rat brains and in rat cerebellar cultured cells. The acidic pI (5.2-5.4) of the rat brain protein revealed by isoelectric focusing is in good agreement with that of the protein coded for by the calponin isoform mRNA described by Applegate et al. and is different from that of the protein from chicken gizzard (pI 9.9). Brain calponin-like protein is different from two other Ca(2+)-calmodulin-binding proteins previously identified in brain, namely caldesmon and adducin, and from tropomyosin.

scholarly journals On the potential of hand-held GPS tracking of fjord ice features for remote-sensing validation

2017 ◽  
Vol 59 (76pt2) ◽  
pp. 173-180 ◽  
Author(s):  
Jean Negrel ◽  
Sebastian Gerland ◽  
Anthony P. Doulgeris ◽  
Tom Rune Lauknes ◽  
Line Rouyet
Keyword(s):  
Remote Sensing ◽  
The Arctic ◽  
Gps Tracking ◽  
Good Opportunity ◽  
Satellite Radar ◽  
Gps Tracks ◽  
Remote Sensing Techniques ◽  
Gps Devices ◽  
Good Agreement

ABSTRACTResearch on young thin sea ice is essential to understand the changes in the Arctic. But it is also the most challenging to investigate, both in situ and from satellites. If satellite remote-sensing techniques are developing rapidly, fieldwork remains crucial for the mandatory validation of such data. In April 2016, an Arctic fieldwork campaign was conducted at Kongsfjorden, Svalbard. This campaign provided an opportunity to combine various techniques to record the fjord ice properties ranging from local field sampling to broader ground-based and satellite radar remote sensing of the fjord. Tracking the boat used to access the field sites with hand-held GPS devices offered a good opportunity to map fjord ice and assess the limits of radar identification of small icebergs and thin ice. During 1 week, 17 icebergs and the thin ice edges in two different locations were mapped. The GPS tracks present a good agreement with the Radarsat-2 data analysis for one of the two ice edges. The second ice edge track only partly corresponds to the radar scene. Ice movement, recorded by a ground-based radar, is likely to explain this result. Grounded icebergs could be identified in both Radarsat-2 and ground-based radar.

scholarly journals Contribution to the understanding of the cycle of the protozoan parasite Marteilia refringens

Parasitology ◽  
2013 ◽  
Vol 141 (2) ◽  
pp. 227-240 ◽  
Author(s):  
I. ARZUL ◽  
B. CHOLLET ◽  
S. BOYER ◽  
D. BONNET ◽  
J. GAILLARD ◽  
...  
Keyword(s):  
Mytilus Galloprovincialis ◽  
Protozoan Parasite ◽  
Copepod Species ◽  
Ostrea Edulis ◽  
Positive Signal ◽  
One Year ◽  
Definition Of ◽  
First Time

SUMMARYThe paramyxean parasite Marteilia refringens infects several bivalve species including European flat oysters Ostrea edulis and Mediterranean mussels Mytilus galloprovincialis. Sequence polymorphism allowed definition of three parasite types ‘M’, ‘O’ and ‘C’ preferably detected in oysters, mussels and cockles respectively. Transmission of the infection from infected bivalves to copepods Paracartia grani could be experimentally achieved but assays from copepods to bivalves failed. In order to contribute to the elucidation of the M. refringens life cycle, the dynamics of the infection was investigated in O. edulis, M. galloprovincialis and zooplankton over one year in Diana lagoon, Corsica (France). Flat oysters appeared non-infected while mussels were infected part of the year, showing highest prevalence in summertime. The parasite was detected by PCR in zooplankton particularly after the peak of prevalence in mussels. Several zooplanktonic groups including copepods, Cladocera, Appendicularia, Chaetognatha and Polychaeta appeared PCR positive. However, only the copepod species Paracartia latisetosa showed positive signal by in situ hybridization. Small parasite cells were observed in gonadal tissues of female copepods demonstrating for the first time that a copepod species other than P. grani can be infected with M. refringens. Molecular characterization of the parasite infecting mussels and zooplankton allowed the distinguishing of three Marteilia types in the lagoon.

scholarly journals Exploiting White-Light Observations to Improve Estimates of Magnetic Connectivity

2021 ◽  
Vol 8 ◽  
Author(s):  
Nicolas Poirier ◽  
Alexis P. Rouillard ◽  
Athanasios Kouloumvakos ◽  
Alexis Przybylak ◽  
Naïs Fargette ◽  
...  
Keyword(s):  
White Light ◽  
Solar Wind Plasma ◽  
Magnetic Polarity ◽  
Model Parameters ◽  
The Sun ◽  
Heliospheric Observatory ◽  
Practical Applications ◽  
One Year ◽  
First Time

The Solar Orbiter (SolO) and Parker Solar Probe missions have opened up new challenges for the heliospheric scientific community. Their proximity to the Sun and their high quality measurements allow us to investigate, for the first time, potential sources for the solar wind plasma measured in situ. More accurate estimates of magnetic connectivities from spacecraft to the Sun are required to support science and operations for these missions. We present a methodology to systematically compare coronal and heliospheric models against white-light (WL) observations. WL images from the SOlar and Heliospheric Observatory (SoHO) are processed to unveil the faint structures of the K-corona. Images are then concatenated over time and are projected into a Carrington synoptic map. Features of interest such as the Streamer Belt (SB) are reduced to simplified geometric objects. Finally, a metric is defined to rank models according to their performance against WL observations. The method has been exploited to reproduce magnetic sectors from WL observations. We tested our results against one year of in situ magnetic polarity measurements taken at near one AU from the Advanced Composition Explorer (ACE) and the Solar TErrestrial RElations Observatory (STEREO-A). We obtained a good correlation that emphasizes the relevance of using WL observations to infer the shape of the sector structure. We show that WL observations provide additional constraints to better select model parameters such as the input photospheric magnetic map. We highlight the capability of this technique to systematically optimize coronal and heliospheric models using continuous and near-real-time WL observations. Several relevant practical applications are discussed, which should allow us to improve connectivity estimates.

scholarly journals Long-term aerosol optical hygroscopicity study at the ACTRIS SIRTA observatory: synergy between ceilometer and in situ measurements

2019 ◽  
Vol 19 (11) ◽  
pp. 7883-7896 ◽  
Author(s):  
Andrés Esteban Bedoya-Velásquez ◽  
Gloria Titos ◽  
Juan Antonio Bravo-Aranda ◽  
Martial Haeffelin ◽  
Olivier Favez ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Mass Fraction ◽  
In Situ Measurements ◽  
Hygroscopic Growth ◽  
Ambient Aerosols ◽  
Inorganic Species ◽  
Remote Sensing Techniques ◽  
First Time ◽  
Aerosol Hygroscopicity

Abstract. An experimental setup to study aerosol hygroscopicity is proposed based on the temporal evolution of attenuated backscatter coefficients from a ceilometer colocated with an instrumented tower equipped with meteorological sensors at different heights. This setup is used to analyze a 4.5-year database at the ACTRIS SIRTA observatory in Palaiseau (Paris, France, 2.208∘ E, 48.713∘ N; 160 m above sea level). A strict criterion-based procedure has been established to identify hygroscopic growth cases using ancillary information, such as online chemical composition, resulting in 8 hygroscopic growth cases from a total of 107 potential cases. For these eight cases, hygroscopic growth-related properties, such as the attenuated backscatter enhancement factor fβ (RH) and the hygroscopic growth coefficient γ, are evaluated. This study shows that the hygroscopicity parameter γ is negatively correlated with the aerosol organic mass fraction but shows a positive correlation with the aerosol inorganic mass fraction. Among inorganic species, nitrate exhibited the highest correlation. This is the first time that hygroscopic enhancement factors are directly retrieved under ambient aerosols using remote-sensing techniques, which are combined with online chemical composition in situ measurements to evaluate the role of the different aerosol species in aerosol hygroscopicity.

scholarly journals A Theoretical Multifractal Model for Assessing Urea Release from Chitosan Based Formulations

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1264 ◽  
Author(s):  
Manuela Maria Iftime ◽  
Stefan Andrei Irimiciuc ◽  
Maricel Agop ◽  
Marian Angheloiu ◽  
Lacramioara Ochiuz ◽  
...  
Keyword(s):  
Empirical Data ◽  
Polarized Light ◽  
First Order ◽  
Fertilizer Release ◽  
Urea Release ◽  
Release Data ◽  
First Time ◽  
Good Agreement

This paper reports the calibration of a theoretical multifractal model based on empirical data on the urea release from a series of soil conditioner systems. To do this, a series of formulations was prepared by in situ hydrogelation of chitosan with salicylaldehyde in the presence of different urea amounts. The formulations were morphologically characterized by scanning electron microscopy and polarized light microscopy. The in vitro urea release was investigated in an environmentally simulated medium. The release data were fitted on five different mathematical models, Korsmeyer–Peppas, Zero order, First order, Higuchi and Hixson–Crowell, which allowed the establishment of a mechanism of urea release. Furthermore, a multifractal model, used for the fertilizer release for the first time, was calibrated using these empirical data. The resulting fit was in good agreement with the experimental data, validating the multifractal theoretical model.

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