11 research outputs found
Modern forms of foreign language distance learning in aquaculture
This article is devoted to a rather relevant topic of the 21st century. The subject of the analysis of the article is distance learning. The object of this article is a comparative analysis of distance learning in different countries. In recent years, the use of modern technical means has become a popular phenomenon in education all over the world. Information educational technologies have been intensively developed and increasingly used in the daily educational process along with traditional forms of education in many countries of the world. In this article, we consider the use of distance education in different countries, which helps to expand access to education and training for everyone. The choice of the topic is due to the relevance and the need to study distance education as an innovative form of education from various points of view. The authors analyze the use of distance learning sampled in various countries. The theoretical significance of the study lies in the fact that the data obtained can contribute to the deepened study of distance learning. The practical significance lies in the fact that the data obtained can be used in the course of modern pedagogy and methodology, in special courses on the problems of modern education
Modern forms of foreign language distance learning in aquaculture
This article is devoted to a rather relevant topic of the 21st century. The subject of the analysis of the article is distance learning. The object of this article is a comparative analysis of distance learning in different countries. In recent years, the use of modern technical means has become a popular phenomenon in education all over the world. Information educational technologies have been intensively developed and increasingly used in the daily educational process along with traditional forms of education in many countries of the world. In this article, we consider the use of distance education in different countries, which helps to expand access to education and training for everyone. The choice of the topic is due to the relevance and the need to study distance education as an innovative form of education from various points of view. The authors analyze the use of distance learning sampled in various countries. The theoretical significance of the study lies in the fact that the data obtained can contribute to the deepened study of distance learning. The practical significance lies in the fact that the data obtained can be used in the course of modern pedagogy and methodology, in special courses on the problems of modern education
Infrared Optical Constants of Organic Aerosols: Organic Acids and Model Humic-Like Substances (HULIS)
<div><p>Aerosols are important atmospheric constituents as they impact the Earth's energy balance and climate. An analysis of the impact of aerosols depends on the detailed knowledge of aerosol optical properties. However, there is a lack of refractive index data for atmospherically relevant organic compounds in the infrared (IR) region which complicates the quantitative estimation of the aerosol influence on the radiative balance. In this study, we investigate the optical properties of atmospherically relevant carboxylic acids and HUmic-LIke Substances (HULIS) proxies. Aerosol size distributions are measured simultaneously with Fourier transform infrared (FTIR) extinction spectra to calculate the complex refractive index. Scanning electron microscopy (SEM) images are also collected to investigate particle shape. Analysis of SEM images shows evidence for agglomeration in some cases. The experimentally measured IR resonances do not appear to be highly sensitive to agglomeration effects. However, there is an increase in the scattering efficiency at shorter wavelengths as the result of larger overall particle size of the agglomerates. Refractive indices are retrieved from the IR extinction spectra of organic acids and HULIS proxies. Mie simulation results confirm the quality of the retrieved optical constants. Interestingly, the optical constants determined for the acids are in agreement with the published data for fire smoke plumes.</p><p>Copyright 2014 American Association for Aerosol Research</p></div
Size Matters in the Water Uptake and Hygroscopic Growth of Atmospherically Relevant Multicomponent Aerosol Particles
Understanding the interactions of
water with atmospheric aerosols
is crucial for determining the size, physical state, reactivity, and
climate impacts of this important component of the Earth’s
atmosphere. Here we show that water uptake and hygroscopic growth
of multicomponent, atmospherically relevant particles can be size
dependent when comparing 100 nm versus ca. 6 μm sized particles.
It was determined that particles composed of ammonium sulfate with
succinic acid and of a mixture of chlorides typical of the marine
environment show size-dependent hygroscopic behavior. Microscopic
analysis of the distribution of components within the aerosol particles
show that the size dependence is due to differences in the mixing
state, that is, whether particles are homogeneously mixed or phase
separated, for different sized particles. This morphology-dependent
hygroscopicity has consequences for heterogeneous atmospheric chemistry
as well as aerosol interactions with electromagnetic radiation and
clouds
Linking hygroscopicity and the surface microstructure of model inorganic salts, simple and complex carbohydrates, and authentic sea spray aerosol particles.
Individual airborne sea spray aerosol (SSA) particles show diversity in their morphologies and water uptake properties that are highly dependent on the biological, chemical, and physical processes within the sea subsurface and the sea surface microlayer. In this study, hygroscopicity data for model systems of organic compounds of marine origin mixed with NaCl are compared to data for authentic SSA samples collected in an ocean-atmosphere facility providing insights into the SSA particle growth, phase transitions and interactions with water vapor in the atmosphere. In particular, we combine single particle morphology analyses using atomic force microscopy (AFM) with hygroscopic growth measurements in order to provide important insights into particle hygroscopicity and the surface microstructure. For model systems, a range of simple and complex carbohydrates were studied including glucose, maltose, sucrose, laminarin, sodium alginate, and lipopolysaccharides. The measured hygroscopic growth was compared with predictions from the Extended-Aerosol Inorganics Model (E-AIM). It is shown here that the E-AIM model describes well the deliquescence transition and hygroscopic growth at low mass ratios but not as well for high ratios, most likely due to a high organic volume fraction. AFM imaging reveals that the equilibrium morphology of these single-component organic particles is amorphous. When NaCl is mixed with the organics, the particles adopt a core-shell morphology with a cubic NaCl core and the organics forming a shell similar to what is observed for the authentic SSA samples. The observation of such core-shell morphologies is found to be highly dependent on the salt to organic ratio and varies depending on the nature and solubility of the organic component. Additionally, single particle organic volume fraction AFM analysis of NaCl : glucose and NaCl : laminarin mixtures shows that the ratio of salt to organics in solution does not correspond exactly for individual particles - showing diversity within the ensemble of particles produced even for a simple two component system
Substrate-Deposited Sea Spray Aerosol Particles: Influence of Analytical Method, Substrate, and Storage Conditions on Particle Size, Phase, and Morphology
Atmospheric
aerosols are often collected on substrates and analyzed
weeks or months after the initial collection. We investigated how
the selection of substrate and microscopy method influence the measured
size, phase, and morphology of sea spray aerosol (SSA) particles and
how sample storage conditions affect individual particles using three
common microscopy techniques: optical microscopy, atomic force microscopy,
and scanning electron microscopy. Micro-Raman spectroscopy was used
to determine changes in the water content of stored particles. The
results show that microscopy techniques operating under ambient conditions
provide the most relevant and robust measurement of particle size.
Samples
stored in a desiccator and at ambient conditions leads to similar
sizes and morphologies, while storage that involves freezing and thawing
leads to irreversible changes due to phase changes and water condensation.
Typically, SSA particles are deposited wet and, if possible, samples
used for single-particle analysis should be stored at or near conditions
at which they were collected in order to avoid dehydration. However,
if samples need to be dry, as is often the case, then this study found
that storing SSA particles at ambient laboratory conditions (17–23%
RH and 19–21 °C) was effective at preserving them and
reducing changes that would alter samples and subsequent data interpretation
Analysis of Organic Anionic Surfactants in Fine and Coarse Fractions of Freshly Emitted Sea Spray Aerosol
The inclusion of organic compounds
in freshly emitted sea spray
aerosol (SSA) has been shown to be size-dependent, with an increasing
organic fraction in smaller particles. Here we have used electrospray
ionization-high resolution mass spectrometry in negative ion mode
to identify organic compounds in nascent sea spray collected throughout
a 25 day mesocosm experiment. Over 280 organic compounds from ten
major homologous series were tentatively identified, including saturated
(C<sub>8</sub>–C<sub>24</sub>) and unsaturated (C<sub>12</sub>–C<sub>22</sub>) fatty acids, fatty acid derivatives (including
saturated oxo-fatty acids (C<sub>5</sub>–C<sub>18</sub>) and
saturated hydroxy-fatty acids (C<sub>5</sub>–C<sub>18</sub>), organosulfates (C<sub>2</sub>–C<sub>7</sub>, C<sub>12</sub>–C<sub>17</sub>) and sulfonates (C<sub>16</sub>–C<sub>22</sub>). During the mesocosm, the distributions of molecules within
some homologous series responded to variations among the levels of
phytoplankton and bacteria in the seawater. The average molecular
weight and carbon preference index of saturated fatty acids significantly
decreased within fine SSA during the progression of the mesocosm,
which was not observed in coarse SSA, sea-surface microlayer or in
fresh seawater. This study helps to define the molecular composition
of nascent SSA and biological processes in the ocean relate to SSA
composition
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Microbial Control of Sea Spray Aerosol Composition: A Tale of Two Blooms.
With the oceans covering 71% of the Earth, sea spray aerosol (SSA) particles profoundly impact climate through their ability to scatter solar radiation and serve as seeds for cloud formation. The climate properties can change when sea salt particles become mixed with insoluble organic material formed in ocean regions with phytoplankton blooms. Currently, the extent to which SSA chemical composition and climate properties are altered by biological processes in the ocean is uncertain. To better understand the factors controlling SSA composition, we carried out a mesocosm study in an isolated ocean-atmosphere facility containing 3,400 gallons of natural seawater. Over the course of the study, two successive phytoplankton blooms resulted in SSA with vastly different composition and properties. During the first bloom, aliphatic-rich organics were enhanced in submicron SSA and tracked the abundance of phytoplankton as indicated by chlorophyll-a concentrations. In contrast, the second bloom showed no enhancement of organic species in submicron particles. A concurrent increase in ice nucleating SSA particles was also observed only during the first bloom. Analysis of the temporal variability in the concentration of aliphatic-rich organic species, using a kinetic model, suggests that the observed enhancement in SSA organic content is set by a delicate balance between the rate of phytoplankton primary production of labile lipids and enzymatic induced degradation. This study establishes a mechanistic framework indicating that biological processes in the ocean and SSA chemical composition are coupled not simply by ocean chlorophyll-a concentrations, but are modulated by microbial degradation processes. This work provides unique insight into the biological, chemical, and physical processes that control SSA chemical composition, that when properly accounted for may explain the observed differences in SSA composition between field studies