scholarly journals Hydrostatic differential meter of local density of natural waters

2021 ◽  
pp. 50-58
Author(s):  
V.A. Gaisky ◽  
Keyword(s):  
Natural Waters ◽  
Local Density ◽  
Pressure Sensors ◽  
External Pressure ◽  
Vertical Tube ◽  
Weighted Sum ◽  
The Third ◽  
Density Of Water ◽  
Measured Density ◽  
Reference Liquid

Variants of constructing meters of local density of natural waters in deep-water instruments are proposed. In the first variant, the density of water is determined as the sum of the density of the reference liquid in a vertical tube with access in the middle of the tube of external pressure and the weighted sum of the readings of differential pressure sensors at the ends of the tube. The second version contains two identical basic or simplified meters with different densities of the reference liquid. In the third variant, n primary meters are used, from which n sub-bands or 2 С n results of pairwise measurements are formed. In the fourth version, one or more primary or simplified meters are used, which are adjusted to the measured density by changing the temperature.

scholarly journals Principles of construction of a hydrostatic differential meter of local density of natural waters

2021 ◽  
Author(s):  
V.A. Gaisky ◽  
Keyword(s):  
Deep Sea ◽  
Natural Waters ◽  
Local Density ◽  
Density Of Water

A number of variants of devices for measuring the local density of water in deep-sea devices are proposed.

scholarly journals Simulating the Impact of the Internal Structure of Phytoplankton on the Bulk Particulate Backscattering Ratio using a Two-Layered Spherical Geometry for Cells

2018 ◽  
Author(s):  
Lucile Duforêt-Gaurier ◽  
David Dessailly ◽  
William Moutier ◽  
Hubert Loisel
Keyword(s):  
Coastal Waters ◽  
Natural Waters ◽  
Heterotrophic Bacteria ◽  
Relative Concentration ◽  
Spherical Geometry ◽  
The Third ◽  
Study Case ◽  
Coated Spheres ◽  
The Impact ◽  
Phytoplankton Cells

The bulk backscattering ratio ($\tilde{b_{bp}}$) is commonly used as a descriptor of the bulk real refractive index of the particulate assemblage in natural waters. Based on numerical simulations, we analyze the impact of heterogeneity of phytoplankton cells on $\tilde{b_{bp}}$. $\tilde{b_{bp}}$ is modeled considering viruses, heterotrophic bacteria, phytoplankton, detritus, and minerals. Three study cases are defined according to the relative abundance of these different components. Two study cases represent typical situations in open ocean, outside (No-B/No-M) and inside bloom (B/No-M). The third study case is typical of coastal waters with the presence of minerals. Phytoplankton cells are modeled by a two-layered spherical geometry representing a chloroplast surrounding the cytoplasm. The $\tilde{b_{bp}}$ values are higher when heterogeneity is considered because the contribution of coated spheres to backscattering is higher than homogeneous spheres. The impact of heterogeneity is however strongly conditioned by the hyperbolic slope $\xi$ of the particle size distribution. Even if the relative concentration of phytoplankton is small (<1%), $\tilde{b_{bp}}$ increases by about 60% (for $\xi=4.3$ and for the No-B/No-M water body), when the heterogeneity is taken into account, in comparison with a particulate population only composed by homogeneous spheres. As expected, heterogeneity has a much smaller impact (about 5$\%$ for $\xi=4.3$) on $\tilde{b_{bp}}$ when minerals are added.

A broad spectrum analytical scheme for the screening of endocrine disruptors (EDs), pharmaceuticals and personal care products in wastewaters and natural waters

2002 ◽  
Vol 46 (3) ◽  
pp. 97-104 ◽  
Author(s):  
A. Bruchet ◽  
C. Prompsy ◽  
G. Filippi ◽  
A. Souali
Keyword(s):  
Broad Spectrum ◽  
Natural Waters ◽  
Personal Care Products ◽  
Pharmaceutical Compounds ◽  
Personal Care ◽  
Organic Micropollutants ◽  
Glycol Ethers ◽  
The Third ◽  
Analytical Scheme ◽  
Pharmaceutical Industries

This paper describes the implementation of a broad-spectrum analytical scheme which was used at three wastewater plants for the screening of organic micropollutants. The more than 200 compounds identified comprised a variety of endocrine disrupters, pharmaceutical compounds and personal care products. Glycol ethers which have well established effects on the development of the embryo were outstanding in all plants investigated. The first plant, which was investigated at various stages of treatment, was quite efficient at removing undesirable compounds. The second plant, which received 50% of effluents from pharmaceutical industries, released low but significant levels of drugs. An antibiotic, cyclamidomycine, was identified in the effluent from the third plant.

Accuracy of the vertical tube shift method in identifying the relationship between the third molars and the mandibular canal

2014 ◽  
Vol 19 (3) ◽  
pp. 583-588 ◽  
Author(s):  
Sergio Lins de-Azevedo-Vaz ◽  
Anne Caroline Costa Oenning ◽  
Marcela Graciano Felizardo ◽  
Francisco Haiter-Neto ◽  
Deborah Queiroz de Freitas
Keyword(s):  
Mandibular Canal ◽  
Vertical Tube ◽  
Third Molars ◽  
Shift Method ◽  
The Third ◽  
The Relationship

Simulation of three variants of population dynamics with large reproductive potential in a new environment

2021 ◽  
pp. 21-43
Author(s):  
Андрей Юрьевич Переварюха
Keyword(s):  
Insect Pests ◽  
Reproductive Potential ◽  
Stable State ◽  
Reproductive Activity ◽  
External Pressure ◽  
Interspecies Interaction ◽  
Bacterial Colony ◽  
Oscillatory Dynamics ◽  
The Third ◽  
Stable Development

Предложены модели на основе уравнений с запаздывающей регуляцией и отложенным включением противодействия для динамики инвазивных популяций с высоким репродуктивным потенциалом. В новой среде интродуценты с большим r -параметром способны демонстрировать нестационарные и экстремальные режимы изменения численности из-за некомпенсируемой репродуктивной активности. Истощение необходимых им ресурсов делает невозможными орбитально устойчивые циклы. Уравнения в вычислительных сценариях описывают: 1) стабилизацию малочисленной группы после однократной вспышки и коллапса; 2) гибель вселенца при колебательной динамике с запаздывающим внешним давлением; 3) успешное прохождение популяцией с логистическим типом роста предкритического минимума при адаптации к резко усилившемуся противоборству - распространенный сценарий кризиса на подъеме, подтвержденный экспериментами. Третье уравнение отражает актуальное межвидовое взаимодействие с пороговой регуляцией. Развитие моделируемой ситуации заканчивается стабильным состоянием после глубокого кризиса в фазе быстрого роста численности. Сценарий основан на данных экспериментов с интродукцией вируса-бактериофага в колонию бактерий с механизмом защиты CRISPR-Cas. The research addresses mathematical description of three nontrivial avenues for development of population processes. Such events arise after invasions of aggressive species. Invasive processes do not lead to an equilibrium (stable balance) between ecosystems and the environment or regular cyclical changes. The method we have chosen allows simulation of several variants for the reaction of the environment to the appearance of a competitor with a large reproductive potential. We discarded the idea of interpreting the balance capacity of the ecological niche, but used threshold levels for the reaction of the environment instead. We have proposed models based on equations with delayed regulation and delayed activation of counteraction for the dynamics of invasive populations in an environment without mechanisms controlling their reproduction. Some species, when introduced into a new habitat, are able to demonstrate nonstationary and extreme regimes of growths due to uncompensated reproductive activity. The species with a large r -parameter deplete significant resources they need to live, which make stable development impossible, including orbitally stable cycles. We have developed new equations that describe the following scenarios: 1) boom-bust dynamics stabilization at the level of a small group after a single outbreak is the most common scenario for insect pests; 2) the destruction and disappearance of the invader during the oscillatory dynamics and with the regulation with delayed external pressure; 3) scenario for a threshold crisis - successful passage of a population with a logistic increase in the subcritical minimum while adapting to a suddenly intensified confrontation. It is a frequently observed variant that confirmed by experiments with bacterial colonies. The third variant of our modification of the equation describes the most interesting scenario of interspecies interaction with threshold regulation. Development of simulated situation here ends up in stable state after the deep crisis during phase of rapid growth of the population size. We substantiated the model scenario based on experimental data for introduction of the bacteriophage virus into bacterial colony with the CRISPR-Cas mechanism. Our models can be used to study variability of the immune response.

HARMONIC GENERATIONS OF CLUSTER Na2 IN ULTRASHORT INTENSE LASER PULSES

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2687-2692 ◽  
Author(s):  
F. S. ZHANG ◽  
F. WANG ◽  
Y. ABE
Keyword(s):  
Harmonic Generation ◽  
Local Density ◽  
Laser Pulses ◽  
Time Dependent ◽  
Intense Laser ◽  
Density Approximation ◽  
The Third ◽  
Intense Laser Pulses ◽  
Laser Frequencies ◽  
Ponderomotive Potential

In the framework of the time dependent local density approximation the harmonic generation of Na2 in ultrashort intense pulses is investigated. The coupling between harmonics and plasmons of Na 2 is discussed in detail with two laser frequencies 5.266 eV, which is double the resonance of the plasmon, and 1.124 eV, which is half the frequency of plasmons, and with two different peak intensities. One finds appearance of the third and the fifth harmonic generation at high ponderomotive potential.

Density Functional Study of the Structural Properties of Copper Iodide: LDA vs GGA Calculations

2009 ◽  
Vol 5 ◽  
pp. 25-30 ◽  
Author(s):  
Heribert Hernández-Cocoletzi ◽  
Gregorio H. Cocoletzi ◽  
J.F. Rivas-Silva ◽  
A. Flores ◽  
Noboru Takeuchi
Keyword(s):  
Structural Properties ◽  
Ground State ◽  
Density Functional ◽  
Local Density ◽  
Structural Parameters ◽  
External Pressure ◽  
Functional Study ◽  
Full Potential ◽  
Copper Iodide ◽  
Generalized Gradient

We have performed first principles total energy calculations to investigate the structural properties of copper iodide (CuI) in its sodium chloride, cesium chloride, zincblende and wurtzite structures. Calculations are done using the density functional theory. We employ the full potential linearized augmented plane wave method as implemented in the wien2k code. The exchange and correlation potential energies are treated in the generalized gradient approximation (GGA), and the local density approximation (LDA). Optical absorption experiments and x-ray diffraction measurements have shown that zincblende is the ground state of CuI. Our calculations find that in the GGA formalism wurtzite and zincblende have similar total energies, while in the LDA formalism the lowest minimum corresponds to zincblende. Results show that the energy difference between the wurtzite and the zincblende structures, as calculated within the GGA formalism is 2 meV, and within the LDA formalism, is 31 meV. These results may suggest a coexistence of both wurtzite and zincblende structures in the ground state of CuI. Structural parameters are correctly reproduced by the GGA calculations. We obtain that under the application of external pressure the atomic configuration may transform into the NaCl structure. At higher pressures it is possible to have a phase transition to the CsCl geometry.

Evaluating ecological vulnerability over Qinghai-Tibetan Plateau based on remote sensing and geographic information systems

2020 ◽  
Author(s):  
Mu Xia ◽  
Kun Jia
Keyword(s):  
Remote Sensing ◽  
Tibetan Plateau ◽  
Vulnerability Index ◽  
Geographic Information ◽  
Entropy Method ◽  
Weighted Sum ◽  
Spatial And Temporal Patterns ◽  
The Third ◽  
External Pressures ◽  
Ecological Vulnerability

<p>Qinghai-Tibetan Plateau (QTP), known as “the Third Pole”, has one of the most fragile ecosystems in the world. QTP is suffering from external pressures of climate change, human activities, and natural hazards. This study provides a subjective framework in assessing ecological vulnerability (EV) in QTP from 2000 to 2015 based on remote sensing and geographic information system techniques. An ecological vulnerability index (EVI) was established based on 17 indicators mainly acquired from satellite data. Principle component analysis and entropy method were used in determining indicator weights. Annual EVI were calculated based on the weighted sum of all indicators. Five vulnerability levels of potential, light, moderate, heavy and very heavy were graded to describe the spatial and temporal patterns of EVIs. Mann-Kendall trend analysis was performed over QTP during the 16 years. Results indicates QTP is suffering from an overall increasing EVI from eastern to western areas. About 10.43% of QTP has experienced significant EVI decrease, while 7.38% experienced significant increase in EVI.</p><p></p><div> <div> </div> </div><p></p>

Microballoon pressure sensors for particle imaging manometry in liquid and gaseous media

The Analyst ◽  
2016 ◽  
Vol 141 (4) ◽  
pp. 1413-1420 ◽  
Author(s):  
N. Banerjee ◽  
C. H. Mastrangelo
Keyword(s):  
Pressure Sensors ◽  
External Pressure ◽  
Gaseous Media ◽  
Particle Imaging ◽  
Pressure Changes

We present the fabrication and testing of engineered microballoon particles that expand and contract under external pressure changes hence serving as microscopic pressure sensors.

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