scholarly journals Selective collection of iron-rich dust particles by natural Trichodesmium colonies

2019 ◽  
Vol 14 (1) ◽  
pp. 91-103 ◽  
Author(s):  
Nivi Kessler ◽  
Rachel Armoza-Zvuloni ◽  
Siyuan Wang ◽  
Subhajit Basu ◽  
Peter K. Weber ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Strong Preference ◽  
Dust Particles ◽  
Gulf Of Aqaba ◽  
Particle Collection ◽  
Free Particles ◽  
Selective Collection ◽  
Number Of Particles

Abstract Dust is an important iron (Fe) source to the ocean, but its utilization by phytoplankton is constrained by rapid sinking and slow dissolution dust-bound iron (dust-Fe). Colonies of the globally important cyanobacterium, Trichodesmium, overcome these constraints by efficient dust capturing and active dust-Fe dissolution. In this study we examined the ability of Trichodesmium colonies to maximize their Fe supply from dust by selectively collecting Fe-rich particles. Testing for selectivity in particle collection, we supplied ~600 individual colonies, collected on multiple days from the Gulf of Aqaba, with natural dust and silica minerals that were either cleaned of or coated with Fe. Using a stereoscope, we counted the number of particles retained by each colony shortly after addition and following 24 h incubation with particles, and documented translocation of particles to the colony core. We observed a strong preference for Fe-rich particles over Fe-free particles in all tested parameters. Moreover, some colonies discarded the Fe-free particles they initially collected. The preferred collection of Fe-rich particles and disposal of Fe-free particles suggest that Trichodesmium can sense Fe and selectively choose Fe-rich dust particles. This ability assists Trichodesmium obtain Fe from dust and facilitate its growth and subsequent contribution to nutrient cycling and productivity in the ocean.

scholarly journals Quantitative analysis of fine dust particles on moss surfaces under laboratory conditions using the example of Brachythecium rutabulum

2021 ◽  
Author(s):  
Bilitis Désirée Vanicela ◽  
Martin Nebel ◽  
Marielle Stephan ◽  
Christoph Riethmüller ◽  
Götz Theo Gresser
Keyword(s):  
Fine Fraction ◽  
Model Organism ◽  
Dust Particles ◽  
Quantitative Detection ◽  
Suitable Model ◽  
Fine Dust ◽  
Sem Images ◽  
Moss Species ◽  
Laboratory Conditions ◽  
Number Of Particles

AbstractThe identification of a model organism for investigations of fine dust deposits on moss leaflets was presented. An optical method with SEM enabled the quantitative detection of fine dust particles in two orders of magnitude. Selection criteria were developed with which further moss species can be identified in order to quantify the number of fine dust particles on moss surfaces using the presented method. Among the five moss species examined, B. rutabulum had proven to be the most suitable model organism for the method presented here. The number of fine dust particles on the moss surface of B. rutabulum was documented during 4 weeks of cultivation in the laboratory using SEM images and a counting method. The fine dust particles were recorded in the order of 10 μm–0.3 μm, divided into two size classes and counted. Under laboratory conditions, the number of particles of the fine fraction 2.4 μm–0.3 μm decreased significantly.

scholarly journals THE MEASUREMENT AND DISTRIBUTION OF WOOD DUST

2010 ◽  
Vol 41 (1) ◽  
pp. 25 ◽  
Author(s):  
Andrea Rosario Proto ◽  
Giuseppe Zimbalatti ◽  
Martino Negri
Keyword(s):  
Health And Safety ◽  
Qualitative Assessment ◽  
Dust Particles ◽  
Wood Dust ◽  
High Concentration ◽  
Dust Emissions ◽  
Carcinogenic Agents ◽  
Prevention Model ◽  
Number Of Particles

In Italy, the woodworking industry presents many issues in terms of occupational health and safety. This study on exposure to wood dust could contribute to the realization of a prevention model in order to limit exposure to carcinogenic agents to the worker. The sampling methodology illustrated the analysis of dust emissions from the woodworking machinery in operation throughout the various processing cycles. The quantitative and qualitative assessment of exposure was performed using two different methodologies. The levels of wood dust were determined according to EN indications and sampling was conducted using IOM and Cyclon personal samplers. The qualitative research of wood dust was performed using an advanced laser air particle counter. This allowed the number of particles present to be counted in real time. The results obtained allowed for an accurate assessment of the quality of the dust emitted inside the workplace during the various processing phases. The study highlighted the distribution of air particles within the different size classes, the exact number of both thin and ultra-thin dusts, and confirmed the high concentration of thin dust particles which can be very harmful to humans.

scholarly journals A new multicopter-based unmanned aerial system for pollen and spores collection in the atmospheric boundary layer

2019 ◽  
Vol 12 (3) ◽  
pp. 1581-1598 ◽  
Author(s):  
Claudio Crazzolara ◽  
Martin Ebner ◽  
Andreas Platis ◽  
Tatiana Miranda ◽  
Jens Bange ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
High Efficiency ◽  
Aerosol Particles ◽  
Pollen Grains ◽  
Dust Particles ◽  
Unmanned Aerial System ◽  
Pollen Concentration ◽  
Concentration Data ◽  
Particle Collection

Abstract. The application of a new particle collection system (PCS) developed in-house and operated on board a commercially available multicopter unmanned aerial vehicle (UAV) is presented as a new unmanned aerial system (UAS) approach for in situ measurement of the concentration of aerosol particles such as pollen grains and spores in the atmospheric boundary layer (ABL). A newly developed impactor is used for high-efficiency particle extraction on board the multicopter UAV. An airflow volume of 0.2 m3 min−1 through the impactor is provided by a battery-powered blower and measured with an on-board mass flow sensor. A bell-mouth-shaped air inlet of the PCS is arranged and oriented on the multicopter UAV to provide substantial isokinetic sampling conditions by advantageously using the airflow pattern generated by the propellers of the multicopter UAV. More than 30 aerosol particle collection flights were carried out near Tübingen in March 2017 at altitudes of up to 300 m above ground level (a.g.l.), each with a sampled air volume of 2 m3. Pollen grains and spores of various genera, as well as large (>20 µm) opaque particles and fine dust particles, were collected, and specific concentrations of up to 100 particles per m3 were determined by visual microscopic analysis. The pollen concentration values measured with the new UAS match well with the pollen concentration data published by the Stiftung Deutscher Polleninformationsdienst (PID) and by MeteoSwiss. A major advantage of the new multicopter-based UAS is the possibility of the identification of collected aerosol particles and the measurement of their concentration with high temporal and spatial resolutions, which can be used inter alia to improve the database for modelling the propagation of aerosol particles in the ABL.

scholarly journals A new multicopter based unmanned aerial system for pollen and spores collection in the atmospheric boundary layer

2018 ◽  
Author(s):  
Claudio Crazzolara ◽  
Martin Ebner ◽  
Andreas Platis ◽  
Tatiana Miranda ◽  
Jens Bange ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Aerosol Particles ◽  
Pollen Grains ◽  
Dust Particles ◽  
Unmanned Aerial System ◽  
Pollen Concentration ◽  
Concentration Data ◽  
Particle Collection ◽  
Air Volume

Abstract. The application of a new particle collection system (PCS) onboard a multicopter unmanned aerial vehicle (UAV) is presented as a new unmanned aerial system (UAS) approach for in-situ measurement of the concentration of aerosol particles such as pollen grains and spores in the atmospheric boundary layer (ABL). A newly developed impactor is used for high efficiency particle extraction onboard the multicopter UAV. An air volume flow of 0.2 m3 per minute through the impactor is provided by a battery powered blower and measured with an onboard mass flow sensor. A bell mouth shaped air intake of the PCS is arranged and oriented on the multicopter UAV to provide substantially isokinetic sampling conditions by advantageously using the airflow pattern generated by the propellers of the multicopter UAV. More than thirty aerosol particle collection flights were carried out near Tübingen in March 2017 at altitudes of up to 300 m above ground level (a.g.l.), each with a sampled air volume of 2 m3. Pollen grains and spores of various genera as well as charcoal and fine dust particles were collected and specific concentrations of up to 100 particles per m3 were determined by visual microscopic analysis. The pollen concentration values measured with the new UAS matches well with the pollen concentration data published by the Stiftung Deutscher Polleninformationsdienst (PID) and by MeteoSchweiz. A major advantage of the new multicopter based UAS is the possibility of the identification of collected aerosol particles and the measurement of their concentration with high temporal and spatial resolution, which can be used inter alia to improve the data base for modelling the propagation of aerosol particles in the ABL.

On the Particles in Fogs and Clouds

1893 ◽  
Vol 19 ◽  
pp. 260-263
Author(s):  
John Aitken
Keyword(s):  
Vapour Pressure ◽  
Dust Particles ◽  
Strong Wind ◽  
Great Care ◽  
Rapid Cooling ◽  
Particle Counter ◽  
Large Curvature ◽  
Small Water ◽  
Made In ◽  
Number Of Particles

At the beginning of the paper some observations made on the water particles in clouds on the Rigi on the 21st of May last are described. Previous observations with the fog-particle counter had shown that there is a relation between the density of a cloud and the number of water particles observed. On the occasion above referred to the number was very much greater than corresponded with the density. It is pointed out that the number of dust particles in the air which become centres of condensation depends on the rate at which the condensation is taking place, quick condensation causing a large number of particles to become active, slow condensation causing a small number; and that after the condensation has ceased a process of differentiation takes place, the larger particles, robbing the smaller ones of their water, owing to the vapour-pressure at the surface of drops of large curvature being less than at the surface of drops of smaller curvature. The particles in a cloud are by this process reduced in number, those remaining becoming larger and falling quicker, the cloud thus tending to become thinner by the reduction of the number of particles and by the falling of some of them. It is shown that the exceptional readings above referred to, obtained on the Rigi, were owing to the observations then made being taken in a new and rapidly-formed cloud, due to the strong wind blowing at the time causing a quick ascent and rapid cooling and condensation, the result being the formation of a large number of very small water particles. Though the number was very great, the particles were so small they were only just visible with great care with the magnifying power used in the instrument. Previous observations on cloud particles had been made in slowly-formed or in old clouds after the process of differentiation had been in play for some time, and after the drops had been reduced in number and increased in size.

scholarly journals An adhesive surface sampling technique for airborne viruses

1970 ◽  
Vol 68 (2) ◽  
pp. 273-282 ◽  
Author(s):  
G. Thomas
Keyword(s):  
Bovine Serum Albumin ◽  
Collection Efficiency ◽  
Sampling Technique ◽  
Petri Dish ◽  
Surface Sampling ◽  
Particle Collection ◽  
Adhesive Surface ◽  
Airborne Viruses ◽  
Andersen Sampler ◽  
Number Of Particles

SUMMARYA mixture of sucrose, glycerol and bovine serum albumin produces a stable coating in a Petri dish which remains adhesive for up to an hour when exposed in a slit sampler. Virus aerosols can be collected on this surface followed the direct addition of cell cultures to demonstrate the presence of viable virus. The technique is applicable to the Andersen sampler. A modified version of this sampler has been produced with the same particle collection efficiency as the standard Andersen sampler. The plaque counts obtained the adhesive surface sampling technique are believed to give an indication of the number of particles collected bearing viable virus.

scholarly journals On the Disordered, Collective and Patterned Movements of Media. Qualitative Analysis of Movements

2019 ◽  
Author(s):  
Géza Lámer
Keyword(s):  
Collective Motion ◽  
Physical Space ◽  
Rigid Bodies ◽  
The State ◽  
Deformable Solid ◽  
Flow Image ◽  
Free Particles ◽  
Deformable Solid Body ◽  
State Functions ◽  
Number Of Particles

The motion of elements is classified from a topological aspect. We separate three different, disordered, collective and patterned motion forms of media. We will reveal what concrete shapes the different type media take. In case of a limited number of particles, a discrete description is suitable for tracking the mechanic behavior of the medium. In case of the large of a number of particles we apply in some sense continuous mathematical model according to the motion occurring in the medium instead of a discrete description. We postulate a statistical distribution to the disordered motion; we "distribute" the particles for the collective motion in the physical space and apply a differential geometric description. We assign continuous flow lines to the regular patterned motion of the medium with free particles while we assign energy dissipation to the flow image an irregular patterned motion. In the case of deformable solid body built by periodically arranged rigid bodies the state functions with discrete domain of definition are represented by functions with continuous domain of definition. Granular conglomerations seem to be the only such medium, which allow tracking of the state of all granules.Disordered motion leads to thermodynamic - statistical description. The collective motion of free particles leads to the description of the laminar flow of particles, the collective motion of fixed particles leads to the classical continuum. The patterned motion of free particles leads to the description of vortex or turbulent flow, the patterned motion of fixed particles leads to grid continua.

scholarly journals I.—On the Number of Dust Particles in the Atmosphere

1889 ◽  
Vol 35 (1) ◽  
pp. 1-19 ◽  
Author(s):  
John Aitken
Keyword(s):  
Good Deal ◽  
Solid Particles ◽  
Dust Particles ◽  
Solid Matter ◽  
Fundamental Point ◽  
Number Of Particles ◽  
Economy Of Nature

The solid matter floating in our atmosphere is every day becoming of greater and greater interest as we are gradually realising the important part it plays in the economy of nature, whether viewed as to its physical, physiological, or meteorological aspects. One fundamental point on which we have at present very little information of anything like a definite character, is as to the number of solid particles present in our atmosphere. We know that they are very numerous, and it seems probable that the number varies under different conditions of weather; but what number of particles are really present under any conditions, and how the number varies, we have at present very little idea. In this field of research the physiologists are far in advance of the physicists, as they have devised means of counting the number of live germs floating in our atmosphere, and already we have a good deal of information as to how the number varies under different conditions.

scholarly journals XIII.—On the Solid and Liquid Particles in Clouds

1892 ◽  
Vol 36 (2) ◽  
pp. 313-319
Author(s):  
John Aitken
Keyword(s):  
Dust Particles ◽  
Short Intervals ◽  
Low Level ◽  
Previous Communication ◽  
Small Instrument ◽  
Number Of Particles

Towards the end of May of this year I made my third visit to the Rigi Kulm, for the purpose of continuing my observations on the amount of dust in the atmosphere and other meteorological phenomena. It was with a feeling of no little satisfaction that I found myself at that elevated situation during broken weather, and under conditions very different from any previously experienced by me. On this occasion I had come in the hope of finding opportunities for making some observations on the conditions existing in clouds, in addition to the usual dust observations, and had brought with me the small instrument for observing the water particles in a fog, described in a previous communication to this Society. As the weather continued to be variable during the week of my visit, I was fortunate enough to succeed in making a number of interesting observations on the water particles in clouds, and also of comparing the conditions in clouds at this elevated situation with those previously observed in fogs at a low level.Before giving the results of my observations on the water particles, it may be desirable to make a few remarks on the solid or dust particles. When making the ordinary dust observations this year, it was frequently noticed that, when surrounded by clouds, the number of particles varied greatly at short intervals of time.

Relaxation of dusty plasmas in plasma crystals

2000 ◽  
Vol 63 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Yu. I. CHUTOV ◽  
O. Yu. KRAVCHENKO ◽  
R. D. SMIRNOV ◽  
P. P. J. M. SCHRAM
Keyword(s):  
Electric Charge ◽  
Dusty Plasmas ◽  
Distribution Functions ◽  
The Self ◽  
Dust Particles ◽  
Relaxation Phenomena ◽  
Electrons And Ions ◽  
Self Consistent ◽  
Plasma Crystals ◽  
Selective Collection

Relaxation phenomena in two-dimensional (2D) plasma crystals have been investigated, including both the self-consistent electric charge of dust particles and the electron and ion velocity distribution functions, by means of a modified 2D particle-in-cell (PIC) method. The results obtained show that the mutual interaction of dust particles in such crystals leads to special properties of the background electrons and ions due to their selective collection by dust particles during the relaxation. These electrons and ions can behave as non-ideal components of dusty plasmas in plasma crystals even in cases where their numbers in the Debye cube are large. This effect is caused by their intensive charge exchange with dust particles, which provides dusty plasmas with the status of open statistical systems. The selective collection of electrons and ions by dust particles also causes their deviation from the initial equilibrium as well as the non-equilibrium evolution of the self-consistent electric charge of the dust particles. Relaxation phenomena in plasma crystals have to be taken into account in all cases of strong changes of plasma parameters, for example due to strong oscillations and waves in these crystals.

Sign in / Sign up

Export Citation Format

Share Document