Water denitrification by displacement biofiltration

This work was aimed creating a simple and reliable submersed biofilter for the decentralized treatment of nitrate-contaminated water. Denitrification of water was studied by the method of displacement (piston) bio-filtration in specially designed devices intended for home application. At certain sizes of grains of bio-filtration bed and filtration flow directions in it, the change in operating mode of denitrifying biofilter from direct flow to displacement mode offers the following advantages. There is no need to maintain a continuous and slow flow of water through the biofilter. The consumers have the opportunity to feed big portions of water into the bio-filter in one gulp (pulse) and nevertheless get the same quantity of denitrified water. The design of created biofilters is simple. Assembling these bio-filters implies the use of materials with a minimum carbon footprint.

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Water denitrification by displacement biofiltration: transition of designed biofilter to the stationary mode

Voprosy Khimii i Khimicheskoi Tekhnologii ◽

10.32434/0321-4095-2021-137-4-21-26 ◽

2021 ◽

pp. 21-26

Author(s):

V.S. Gevod ◽

◽

A.S. Chernova

Keyword(s):

Carbon Footprint ◽

Contaminated Water ◽

Stationary Mode ◽

Decentralized Treatment ◽

Continuous Service ◽

Residential Use ◽

Simple Materials

This work was aimed at creating a simple and reliable submersed biofilter for the decentralized treatment of nitrate-contaminated water. Denitrification of water was performed by the method of displacement (piston) biofiltration in specially designed U-shaped devices intended for residential use. The efficiency of biofiltration in these devices was evaluated under the conditions of their continuous service. The biofilter exhibited an essential increase in the rate of denitrification when transferring to the stationary mode. Hence, the consumer will have the opportunity of supplying big portions of nitrate-contaminated water into the biofilter in one gulp (pulse) and simultaneously getting the same amount of deeply denitrified water. This mode of biofilters exploitation prevents the clogging of the filtration bed and the channeling in it. The design of the created biofilters is rather simple. Materials with a minimum carbon footprint can be used to fabricate these devices.

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Retaining Relative Height Information: An Enhanced Technique for Depression Treatment in Digital Elevation Models

Water ◽

10.3390/w13233347 ◽

2021 ◽

Vol 13 (23) ◽

pp. 3347

Author(s):

Bo Chen ◽

Chunying Ma ◽

Yao Xiao ◽

Hanxin Gao ◽

Peijun Shi ◽

...

Keyword(s):

Complex Terrain ◽

Digital Elevation Models ◽

Treatment Algorithm ◽

Depression Treatment ◽

Direct Flow ◽

Original Algorithm ◽

Drainage Networks ◽

Digital Elevation ◽

Flow Directions ◽

The Difference

This study presents an enhanced variant of the priority-flood based algorithm proposed by Wang and Liu for treating depressions in digital elevation models (DEMs). The enhanced variant redefines spill elevation, the key concept of the original algorithm, as the lowest elevation that a pixel needs to have to ensure a non-ascending path toward the border of the DEM, plus the larger of a small number (~0.001) and the difference between the unaltered elevation values of the focal pixel and its immediate downhill neighbor. This redefinition is adopted to obtain an intermediate elevation surface to direct flow and ultimately to carve the original DEM. Each carving starts from a depression bottom and propagates downstream until a downhill cell is guaranteed in the original DEM. Tests of these algorithms on a complex terrain of the 260,000 km2 Sichuan structural basin in China shows that the enhanced algorithm maximally preserves the original flow directions and extracts realistic drainage networks. Retaining the relative heights, and therefore flow directions, of cells within depressions allows the new algorithm to offer a depressionless DEM with small modification of its origin for further hydrologic applications. The enhanced depression treatment algorithm is provided as the freely available tool BNUSinkRemv.

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The Peculiarities of Oil Displacement in the Process of Oscillating Injection of Polymer Solution into the Bed with Layered Heterogeneity

Prospecting and Development of Oil and Gas Fields ◽

10.31471/1993-9973-2019-3(72)-42-50 ◽

2019 ◽

pp. 42-50

Author(s):

V. G. Pogrebnyak ◽

І. V. Perkun

Keyword(s):

Polymer Solution ◽

Polymer Solutions ◽

Dissipative Function ◽

Filtration Flow ◽

Elastic Deformations ◽

Porous Bed ◽

Water Solutions ◽

Oil Displacement ◽

Displacement Mode ◽

Hydrodynamic Field

The authors study the filtration flow of polyethylene oxide (PEO) water solutions of molecular weights 4∙106 and 6∙106 within the concentration range from 0 to 0.05% when exposed to an oscillating hydrodynamic field. Photographs characterizing the displacement of oil (with a viscosity of 10 to 50 mPa. s) with PEO water solutions from model porous formations with layered heterogeneity have been obtained. They have made it possible to specify the effectiveness of different oil displacement modes. It is shown that pumping a polymer solution into porous heterogeneous strata, while exposing it to oscillating hydrodynamic field, proved to yield a higher oil displacement ratio, as compared with a stationary oil displacement mode. The authors find out the conditions providing the positive influence on elastic deformations effects in the process of enhanced oil recovery by using polymer solutions. If elastic deformations take place, the filtration flow of polymer solutions should be carried out in the oscillating mode, whereas the frequency of the oscillating effect on the filtration flow should correspond to the dissipative function maximum. The stated results of the polymer solution flow research, under model conditions of a porous bed, have confirmed the nonlinearity mechanism of the polymer solutions filtration flow. In essence, the molecular and macromolecular non-linearity mechanism of the polymer solutions filtration flow means that in a porous medium under the influence of quasi-regular longitudinal velocity gradients, there arise self-sustained oscillations of reversible macromolecular deployment; the deployed macromolecules, in turn, influence the structure of the filtration flow, both on the molecular and macromolecular levels. Deformation oscillations of macromolecules and dissolubility of dynamic macromolecular structures formed under the influence of tensile currents result in the energy dissipation increase and the filtration flow nonlinearity. The nonlinearity of polymer solutions filtration flow ensures the alignment of the frontal advance of the polymer solutions within a porous bed with a layered heterogeneity and, consequently, higher oil displacement efficiency.

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Enhancement of Contrast in the CEM and STEM Using Bumpy Specimens and Employing the “Dappled Field” Mode of Operation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052778 ◽

1974 ◽

Vol 32 ◽

pp. 552-553 ◽

Cited By ~ 1

Author(s):

L. Gandolfi ◽

J. Reiffel

Keyword(s):

Operating Mode ◽

Scanning Transmission Electron Microscope ◽

Dark Field ◽

Specimen Preparation ◽

Field Mode ◽

Preparation Methods ◽

Scanning Transmission Electron ◽

Transmission Electron ◽

Mode Of Operation ◽

Scanning Transmission

Calculations have been performed on the contrast obtainable, using the Scanning Transmission Electron Microscope, in the observation of thick specimens. Recent research indicates a revival of an earlier interest in the observation of thin specimens with the view of comparing the attainable contrast using both types of specimens.Potential for biological applications of scanning transmission electron microscopy has led to a proliferation of the literature concerning specimen preparation methods and the controversy over “to stain or not to stain” in combination with the use of the dark field operating mode and the same choice of technique using bright field mode of operation has not yet been resolved.

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Supercontinuum laser-based monochromatic radiant source for detector spectral responsivity characterization in the range 0.9–1.6 μm using absolute cryogenic radiometer

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2020-11-28-33 ◽

2020 ◽

pp. 28-33

Author(s):

A. Yu. Dunaev ◽

A. S. Baturin ◽

V. N. Krutikov ◽

S. P. Morozova

Keyword(s):

Power Distribution ◽

Spectral Power ◽

Feedback System ◽

Operating Mode ◽

Spectral Responsivity ◽

Spectral Power Distribution ◽

Cryogenic Radiometer ◽

Supercontinuum Laser ◽

Radiant Power ◽

Double Monochromator

An improved monochromatic radiant source with spectral bandwidth of 4 nm based on supercontinuum laser and a double monochromator was included in absolute cryogenic radiometer-based facility to improve the accuracy of spectral responsivity measurement in the range 0.9–1.6 μm. The developed feedback system ensures stabilization of monochromatic radiant power with standard deviation up to 0.025 %. Radiant power that proceeds detector under test or absolute cryogenic radiometer varies from 0.1 to 1.5 mW in dependence of wavelength. The spectral power distribution of its monochromatic source for various operating mode is presented.

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Methodology for determining water losses from irrigation canals

Melioration and Water Management ◽

10.32962/0235-2524-2020-5-16-18 ◽

2020 ◽

pp. 16-18

Author(s):

Elena Makarycheva

Keyword(s):

Filtration Rate ◽

Darcy Law ◽

Filtration Flow ◽

Irrigation Canals ◽

Power Functions ◽

Two Phase ◽

Water Losses ◽

Irrigation Channels ◽

Unsteady Filtration ◽

S Curve

The aim of the article is to develop a method for calculating water losses from irrigation channels in determining the permeability of rock in the zone of filtration flow on the basis of the law of infiltration A.N. Kostyakov using the results of studies of free filtration from pits and foundation pits in loess loams. Pressure movement of water in irrigation canals is subject to the laws of two-phase flow, in which – in contrast to the Darcy law for the zone of saturation plays an important role, the volume and its change in time. The filtration rate (VF) increases with increasing rock moisture (θ) along the S-curve, while the pressure gradient (I = dh/dz) decreases. The dependences of these parameters on the pressure are represented by power functions, and their product CDP = VFI does not change in time and can serve as a characteristic of the filtration flow under the channel. When installing paired piezometers near the water chore line in the channel and determining the graph I(t) by the value of the twophase flow constant CDP, it is possible to calculate the filtration rate at a number of times and the water losses during unsteady filtration. Water losses from the channels at equilibrium humidity increases with increasing head according to the formula A.N. Kostyakova, in which the water permeability of rocks is characterized by a steady filtration rate at a head of 1.0 m, and the gradient is the function of pressure. The application of the proposed method of calculating losses in the design of irrigation systems will increase the reliability of the justification of the volume of anti-filtration measures and the forecast of the groundwater level.

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Research and Modelling on Electrical and Thermal Mode of LEDs Operation in the Luminaire

Light & Engineering ◽

10.33383/2017-048 ◽

2018 ◽

pp. 155-162 ◽

Cited By ~ 1

Author(s):

Sergei S. Kapitonov ◽

Anastasia V. Kapitonova ◽

Sergei Yu. Grigorovich ◽

Sergei A. Medvedev ◽

Taher Sobhy

Keyword(s):

Thermal Conditions ◽

Operating Mode ◽

Thermal Processes ◽

Thermal Mode ◽

Crystal Temperature ◽

Premature Failure ◽

Model Based

In the article, the electrical and thermal processes in the LED lamp with varied parameters are investigated. Voltage and current measurements on all LEDs of the luminaire are carried out in the nominal operating mode. The power allocated to each LED is determined. The calculation of the LED crystal temperature was carried out using the developed thermal LED model based on the results of the measurements and by using “Multisim” program. It has been established that the temperature of the crystals of individual LEDs in the luminaire differ significantly, which leads to unfavourable thermal conditions for them and an increased likelihood of premature failure.

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