scholarly journals Summertime total OH reactivity measurements from boreal forest during HUMPPA-COPEC 2010

2012 ◽  
Vol 12 (17) ◽  
pp. 8257-8270 ◽  
Author(s):  
A. C. Nölscher ◽  
J. Williams ◽  
V. Sinha ◽  
T. Custer ◽  
W. Song ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Canopy ◽  
Marked Change ◽  
Reactive Species ◽  
Organic Precursor ◽  
The Impact ◽  
First Time ◽  
Comparative Reactivity

Abstract. Ambient total OH reactivity was measured at the Finnish boreal forest station SMEAR II in Hyytiälä (Latitude 61°51' N; Longitude 24°17' E) in July and August 2010 using the Comparative Reactivity Method (CRM). The CRM – total OH reactivity method – is a direct, in-situ determination of the total loss rate of hydroxyl radicals (OH) caused by all reactive species in air. During the intensive field campaign HUMPPA-COPEC 2010 (Hyytiälä United Measurements of Photochemistry and Particles in Air – Comprehensive Organic Precursor Emission and Concentration study) the total OH reactivity was monitored both inside (18 m) and directly above the forest canopy (24 m) for the first time. The comparison between these two total OH reactivity measurements, absolute values and the temporal variation have been analyzed here. Stable boundary layer conditions during night and turbulent mixing in the daytime induced low and high short-term variability, respectively. The impact on total OH reactivity from biogenic emissions and associated photochemical products was measured under "normal" and "stressed" (i.e. prolonged high temperature) conditions. The advection of biomass burning emissions to the site caused a marked change in the total OH reactivity vertical profile. By comparing the OH reactivity contribution from individually measured compounds and the directly measured total OH reactivity, the size of any unaccounted for or "missing" sink can be deduced for various atmospheric influences. For "normal" boreal conditions a missing OH reactivity of 58%, whereas for "stressed" boreal conditions a missing OH reactivity of 89% was determined. Various sources of not quantified OH reactive species are proposed as possible explanation for the high missing OH reactivity.

scholarly journals Summertime total OH reactivity measurements from boreal forest during HUMPPA-COPEC 2010

2012 ◽  
Vol 12 (3) ◽  
pp. 7419-7452 ◽  
Author(s):  
A. C. Nölscher ◽  
J. Williams ◽  
V. Sinha ◽  
T. Custer ◽  
W. Song ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Canopy ◽  
Marked Change ◽  
Reactive Species ◽  
Organic Precursor ◽  
The Impact ◽  
First Time ◽  
Comparative Reactivity

Abstract. Ambient total OH reactivity was measured at the Finnish boreal forest station SMEAR II in Hyytiälä (Latitude 61°51' N; Longitude 24°17' E) in July and August 2010 using the Comparative Reactivity Method (CRM). The CRM – total OH reactivity method – is a direct, in-situ determination of the total loss rate of hydroxyl radicals (OH) caused by all reactive species in air. During the intensive field campaign HUMPPA-COPEC 2010 (Hyytiälä United Measurements of Photochemistry and Particles in Air – Comprehensive Organic Precursor Emission and Concentration study) the total OH reactivity was monitored both inside (18 m) and directly above the forest canopy (24 m) for the first time. The comparison between these two total OH reactivity measurements, absolute values and the temporal variation have been analyzed here. Stable boundary layer conditions during night and turbulent mixing in the daytime induced low and high short-term variability, respectively. The impact on total OH reactivity from biogenic emissions and associated photochemical products was measured under "normal" and "stressed" (i.e. prolonged high temperature) conditions. The advection of biomass burning emissions to the site caused a marked change in the total OH reactivity vertical profile. By comparing the OH reactivity contribution from individually measured compounds and the directly measured total OH reactivity, the size of any unaccounted for or "missing" sink can be deduced for various atmospheric influences. For "normal" boreal conditions a missing OH reactivity of 58%, whereas for "stressed" boreal conditions a missing OH reactivity of 89% was determined. Various sources of not quantified OH reactive species are proposed as possible explanation for the high missing OH reactivity.

scholarly journals Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM

2019 ◽  
Vol 12 (10) ◽  
pp. 5503-5517 ◽  
Author(s):  
Pascal Hedelt ◽  
Dmitry S. Efremenko ◽  
Diego G. Loyola ◽  
Robert Spurr ◽  
Lieven Clarisse
Keyword(s):  
Sulfur Dioxide ◽  
Accurate Determination ◽  
Volcanic Eruptions ◽  
Critical Parameters ◽  
Layer Height ◽  
Learning Machine ◽  
The Impact ◽  
First Time ◽  
Better Than

Abstract. The accurate determination of the location, height, and loading of sulfur dioxide (SO2) plumes emitted by volcanic eruptions is essential for aviation safety. The SO2 layer height is also one of the most critical parameters with respect to determining the impact on the climate. Retrievals of SO2 plume height have been carried out using satellite UV backscatter measurements, but, until now, such algorithms are very time-consuming. We have developed an extremely fast yet accurate SO2 layer height retrieval using the Full-Physics Inverse Learning Machine (FP_ILM) algorithm. This is the first time the algorithm has been applied to measurements from the TROPOMI instrument onboard the Sentinel-5 Precursor platform. In this paper, we demonstrate the ability of the FP_ILM algorithm to retrieve SO2 plume layer heights in near-real-time applications with an accuracy of better than 2 km for SO2 total columns larger than 20 DU. We present SO2 layer height results for the volcanic eruptions of Sinabung in February 2018, Sierra Negra in June 2018, and Raikoke in June 2019, observed by TROPOMI.

Castaing’s Electron Microprobe and Its Impact on Materials Science

2001 ◽  
Vol 7 (2) ◽  
pp. 178-192 ◽  
Author(s):  
Dale E. Newbury
Keyword(s):  
Electron Microprobe ◽  
Materials Science ◽  
Critical Time ◽  
Materials Engineering ◽  
Macro Scale ◽  
Materials Science And Engineering ◽  
Basic Infrastructure ◽  
The Impact ◽  
First Time

Abstract The development of the electron microprobe by Raymond Castaing provided a great stimulus to materials science at a critical time in its history. For the first time, accurate elemental analysis could be performed with a spatial resolution of 1 µm, well within the dimensions of many microstructural features. The impact of the microprobe occurred across the entire spectrum of materials science and engineering. Contributions to the basic infrastructure of materials science included more accurate and efficient determination of phase diagrams and diffusion coefficients. The study of the microstructure of alloys was greatly enhanced by electron microprobe characterization of major, minor, and trace phases, including contamination. Finally, the electron microprobe has proven to be a critical tool for materials engineering, particularly to study failures, which often begin on a micro-scale and then propagate to the macro-scale with catastrophic results.

scholarly journals The Impact of the Quality of Tap Water and the Properties of Installation Materials on the Formation of Biofilms

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1903 ◽  
Author(s):  
Dorota Papciak ◽  
Barbara Tchórzewska-Cieślak ◽  
Andżelika Domoń ◽  
Anna Wojtuś ◽  
Jakub Żywiec ◽  
...  
Keyword(s):  
Tap Water ◽  
Galvanized Steel ◽  
Phosphorus Compounds ◽  
Plate Count ◽  
Nickel Steel ◽  
Quantitative Analyses ◽  
The Impact ◽  
First Time

The article presents changes in the quality of tap water depending on time spent in installation and its impact on the creation of biofilms on various materials (polyethylene (PE), polyvinyl chloride (PVC), chrome-nickel steel and galvanized steel). For the first time, quantitative analyses of biofilm were performed using methods such as: Adenosine 5’-triphosphate (ATP) measurement, flow cytometry, heterotrophic plate count and using fractographical parameters. In the water, after leaving the experimental installation, the increase of turbidity, content of organic compounds, nitrites and nitrates was found, as well as the decrease in the content of chlorine compounds, dissolved oxygen and phosphorus compounds. There was an increase in the number of mesophilic and psychrophilic bacteria. In addition, the presence of Escherichia coli was also found. The analysis of the quantitative determination of microorganisms in a biofilm indicates that galvanized steel is the most susceptible material for the adhesion of microorganisms. These results were also confirmed by the analysis of the biofilm morphology. The roughness profile, the thickness of the biofilm layer can be estimated at about 300 μm on galvanized steel.

scholarly journals Vertical characterization of Highly Oxygenated Molecules (HOMs) below and above a boreal forest canopy

2017 ◽  
Author(s):  
Qiaozhi Zha ◽  
Chao Yan ◽  
Heikki Junninen ◽  
Matthieu Riva ◽  
Juho Aalto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Boreal Forest ◽  
Forest Canopy ◽  
Mixed Boundary ◽  
Ground Level ◽  
Atmospheric Conditions ◽  
Research Attention ◽  
Significant Research ◽  
First Time

Abstract. While the role of highly oxygenated molecules (HOMs) in new particle formation (NPF) and secondary organic aerosol (SOA) formation is not in dispute, the interplay between HOM chemistry and atmospheric conditions continues to draw significant research attention. During the Influence of Biosphere-Atmosphere Interactions on the Reactive Nitrogen budget (IBAIRN) campaign, profile measurements of neutral HOM molecules below and above the forest canopy were performed for the first time in the boreal forest SMEAR II station during September 2016. The HOM concentrations and composition distributions below and above the canopy were similar, supporting a well-mixed boundary layer approximation during daytime. However, much lower HOM concentration were frequently observed at ground level due to the formation of a shallow decoupled layer below the canopy attached to the forest floor. Near ground HOMs were influenced by the changes in the precursors and oxidants, and enhancement of the loss on surfaces in this layer, while the HOMs above the canopy top were not significantly affected. Our findings also illustrate that near-ground HOM measurements conducted in strong stably stratified conditions might only be representative of a small fraction of the entire nocturnal boundary layer. This might, in turn, influence the growth of newly formed particles and SOA formation below the canopy where a large majority of measurements are typically conducted.

scholarly journals The Impact of Geographical Location on the Chemical Compositions of Pimpinella lutea Desf. Growing in Tunisia

2021 ◽  
Vol 11 (16) ◽  
pp. 7739
Author(s):  
Hekmat AL-Hmadi ◽  
Ridha El Mokni ◽  
Rajesh K. Joshi ◽  
Mohamed L. Ashour ◽  
Saoussen Hammami
Keyword(s):  
Essential Oils ◽  
Geographical Location ◽  
Chemical Compositions ◽  
Different Populations ◽  
High Level ◽  
Physical Environmental Factors ◽  
The Impact ◽  
First Time ◽  
North And South

Essential oils are generally produced to confer the protection of medicinal plants against several natural enemies. Variations of chemical and physical environmental factors exert significant influences on plant development. They hence may affect the quality and quantity of volatile organic metabolites of interest and, therefore, the economic applications of essential oils. This research focused on the effects of the harvest region on the production and analytes present in Tunisian Pimpinella lutea Desf. Apiaceae that were collected in three different growing environments (North and South Bizerta and Tabarka). Essential oils extracted from a variety of genotypes were analyzed, for the first time, using gas chromatography and mass spectrometry (GC/FID and GC/MS). The determination of the percentage of essential oil components allowed the recognition of three chemotypes: α-trans-Bergamotene quantified at a percentage of 18.1% in North Bizerta (NBEO), muurola-4,10(14)-dien-1-β-ol identified in South Bizerta (10.1%, SBEO) and acora-3,7(14)-dien present in a high level of 29.1% in Tabarka population (TEO). The richness of different populations in sesquiterpenes (60.2–78.1%) suggests that Pimpinella lutea Desf. may be used in different industrial segments.

scholarly journals Novel Bionanocellulose/κ-Carrageenan Composites for Tissue Engineering

2018 ◽  
Vol 8 (8) ◽  
pp. 1352 ◽  
Author(s):  
Izabela Cielecka ◽  
Marcin Szustak ◽  
Edyta Gendaszewska-Darmach ◽  
Halina Kalinowska ◽  
Małgorzata Ryngajłło ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Chondrogenic Differentiation ◽  
Expression Patterns ◽  
Swelling Properties ◽  
In Situ Method ◽  
Chondrogenic Phenotype ◽  
The Impact ◽  
First Time ◽  
Water Holding

In this work, novel bacterial cellulose/κ-carrageenan (BNC/κ-Car) composites, being potential scaffolds for tissue engineering (TE), and outperforming the two polymers when used as scaffolds separately, were for the first time obtained using an in situ method, based on the stationary culture of bacteria Komagateibacter xylinus E25. The composites were compared with native BNC in terms of the morphology of fibers, chemical composition, crystallinity, tensile and compression strength, water holding capacity, water retention ratio and swelling properties. Murine chondrogenic ATDC5 cells were applied to assess the utility of the BNC/κ-Car composites as potential scaffolds. The impact of the composites on the cells viability, chondrogenic differentiation, and expression patterns of Col1α1, Col2α1, Runx2, and Sox9, which are indicative of ATDC5 chondrogenic differentiation, was determined. None of the composites obtained in this study caused the chondrocyte hypertrophy. All of them supported the differentiation of ATDC5 cells to more chondrogenic phenotype.

Propagation of Regular HCl Acids in Carbonate Rocks: The Impact of an In Situ Gelled Acid Stage

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Ahmed M. Gomaa ◽  
Hisham A. Nasr-El-Din
Keyword(s):  
Material Balance ◽  
Chemical Species ◽  
Field Studies ◽  
Injection Rate ◽  
The Core ◽  
The Impact ◽  
First Time ◽  
Recent Laboratory ◽  
Injection Rates

Recent laboratory and field studies indicated that polymer-based in situ gelled acids can cause formation damage. Coreflood experiments using single-stage and multistage acids were conducted at 250 °F. 15 wt. % regular HCl and 5 wt. % in situ gelled acid-based on Fe(III) as a crosslinker were the acids that were used in this study. Propagation of acids and crosslinker inside 20 in. long cores was examined for the first time in detail. Stage volume and injection rate, which were the parameters that affect the propagating of various chemical species, were examined. Samples of the core effluent were collected and the concentrations of calcium, crosslinker, and acid were measured. Material balance was conducted to determine the amount of cross-liker that retained in the core. The results show that in situ gelled acid should be pumped at low injection rates. In situ gelled acid at low injection rate instantaneously plugged the tip of the wormhole and did not create additional wormholes inside the core. Therefore, when the final regular acid stage bypassed the gel, it started to propagate from nearly the last point that the first stage ended. In site gelled acid stage volume should not exceed 0.5 PV. No benefits were gained by increasing the volume of in situ gelled acids. Retention of total iron in the core increased in multistage acid treatments, especially at low acid injection rates.

scholarly journals Design and Validation of a Holographic Particle Counter

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4899 ◽  
Author(s):  
Georg Brunnhofer ◽  
Alexander Bergmann ◽  
Andreas Klug ◽  
Martin Kraft
Keyword(s):  
Particle Number ◽  
State Of The Art ◽  
Three Dimensional ◽  
Particle Counter ◽  
Detection And Counting ◽  
Sampling Volume ◽  
Processing Techniques ◽  
The Impact

An in-line holographic particle counter concept is presented and validated where multiple micrometer sized particles are detected in a three dimensional sampling volume, all at once. The proposed PIU is capable of detecting holograms of particles which sizes are in the lower μ m- range. The detection and counting principle is based on common image processing techniques using a customized HT with a result directly relating to the particle number concentration in the recorded sampling volume. The proposed counting unit is mounted ontop of a CNM for comparison with a commercial TSI-3775 CPC. The concept does not only allow for a precise in-situ determination of low particle number concentrations but also enables easy upscaling to higher particle densities (e.g., > 30 . 000 # c c m ) through its linear expandability and option of cascading. The impact of coincidence at higher particle densities is shown and two coincidence correction approaches are presented where, at last, its analogy to the coincidence correction methods used in state-of-the-art CPCs is identified.

scholarly journals The impact of transport across the polar vortex edge on Match ozone loss estimates

2008 ◽  
Vol 8 (3) ◽  
pp. 565-578 ◽  
Author(s):  
J.-U. Grooß ◽  
R. Müller ◽  
P. Konopka ◽  
H.-M. Steinhorst ◽  
A. Engel ◽  
...  
Keyword(s):  
Time Integration ◽  
Polar Vortex ◽  
Lagrangian Model ◽  
Match Method ◽  
Ozone Loss ◽  
Air Sampler ◽  
The Impact ◽  
Loss Rates

Abstract. The Match method for the quantification of polar chemical ozone loss is investigated mainly with respect to the impact of the transport of air masses across the vortex edge. For the winter 2002/03, we show that significant transport across the vortex edge occurred and was simulated by the Chemical Lagrangian Model of the Stratosphere. In-situ observations of inert tracers and ozone from HAGAR on the Geophysica aircraft and balloon-borne sondes, and remote observations from MIPAS on the ENVISAT satellite were reproduced well by CLaMS. The model even reproduced a small vortex remnant that remained a distinct feature until June 2003 and was also observed in-situ by a balloon-borne whole air sampler. We use this CLaMS simulation to quantify the impact of transport across the vortex edge on ozone loss estimates from the Match method. We show that a time integration of the determined vortex average ozone loss rates, as performed in Match, results in a larger ozone loss than the polar vortex average ozone loss in CLaMS. The determination of the Match ozone loss rates is also influenced by the transport of air across the vortex edge. We use the model to investigate how the sampling of the ozone sondes on which Match is based represents the vortex average ozone loss rate. Both the time integration of ozone loss and the determination of ozone loss rates for Match are evaluated using the winter 2002/2003 CLaMS simulation. These impacts can explain the majority of the differences between CLaMS and Match column ozone loss. While the investigated effects somewhat reduce the apparent discrepancy in January ozone loss rates reported earlier, a distinct discrepancy between simulations and Match remains. However, its contribution to the accumulated ozone loss over the winter is not large.

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