scholarly journals STATE OF WATER BIOLOGICAL STOCK RESOURCES IN THE IVANKOVSKOE AND UGLICHCHSKOE RESERVOIRS

2021 ◽  
Vol 22 (1) ◽  
pp. 25-37
Author(s):  
D.V. Goryachev ◽  
◽  
A.I. Nikitenko ◽  
N.N. Klets ◽  
D.A. Gvozdarev ◽  
...  
Keyword(s):  
2018 ◽  
Vol 77 (12) ◽  
pp. 1103-1112
Author(s):  
Ch. Liu ◽  
I. N. Bondarenko ◽  
A. Yu. Panchenko ◽  
N. I. Slipchenko

2019 ◽  
Vol 78 (9) ◽  
pp. 801-811
Author(s):  
Ch. Liu ◽  
I. N. Bondarenko ◽  
A. Yu. Panchenko ◽  
N. I. Slipchenko

2019 ◽  
Vol 13 (2) ◽  
pp. 52-58
Author(s):  
V. B. Korobov ◽  
I. V. Miskevich ◽  
A. S. Lokhov ◽  
K. A. Seredkin

Abstract: pH is one of the most important parameters characterizing the state of water systems. The arithmetic mean values of samples are often used when averaging serial pH measurements in water bodies, as is usually done for other characteristics of the state of the natural environment (temperature, salinity, oxygen concentrations, suspended solids, etc.). However, in this case such an operation is illegal, since the addition of logarithms, which by definition are pH, is non-additive. The authors conducted a study to determine the extent to which pH variability in natural objects such an operation would not distort the results. For this, several samples of the pH index were generated in various ranges of its theoretically possible and natural variability. It was established that with pH variability of less than a unit characteristic of marine pH values, the statistical characteristics of the indicator and [H+ ] concentrations differ slightly, and the medians of the samples coincide. It is concluded that with such ranges characteristic of the waters of the oceans, there is no need to recalculate previously obtained results. However, for the estuaries of rivers flowing into tidal seas, as shown by field measurements, the pH variability in the mixing zone of sea and river waters is several times higher. Similar situations may occur when heavy precipitation falls on the water surface, as well as during floods. In these cases, a simple averaging of the pH values will no longer be correct. In such cases, the use of other averaging algorithms and the choice of stable statistical characteristics are required.


Author(s):  
Igor Mekhantiev

The article provides an overview of regional studies addressing the hygienic safety of recreational and drinking water use of the population of the Upper Don basin, conducted on the territory of the Voronezh region. The results of dissertation research for 1997–2019 and materials of modern scientific publications on the studied problem for 2015–2019, showing priority regional problems of water use of the population of the Upper Don Basin are considered. The data of scientific and practical work and state monitoring on the inconsistency of water quality with current standards in places of recreation at water bodies and drinking water of centralized water supply systems for sanitary and chemical indicators and microbiological safety indicators are presented. A description of the current system for monitoring the state of water resources is presented and attention is drawn to the need for its improvement.


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 590
Author(s):  
Lihua Wan ◽  
Xiaoya Zang ◽  
Juan Fu ◽  
Xuebing Zhou ◽  
Jingsheng Lu ◽  
...  

The large amounts of natural gas in a dense solid phase stored in the confined environment of porous materials have become a new, potential method for storing and transporting natural gas. However, there is no experimental evidence to accurately determine the phase state of water during nanoscale gas hydrate dissociation. The results on the dissociation behavior of methane hydrates confined in a nanosilica gel and the contained water phase state during hydrate dissociation at temperatures below the ice point and under atmospheric pressure are presented. Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD) were used to trace the dissociation of confined methane hydrate synthesized from pore water confined inside the nanosilica gel. The characterization of the confined methane hydrate was also analyzed by PXRD. It was found that the confined methane hydrates dissociated into ultra viscous low-density liquid water (LDL) and methane gas. The results showed that the mechanism of confined methane hydrate dissociation at temperatures below the ice point depended on the phase state of water during hydrate dissociation.


2021 ◽  
Vol 6 (5) ◽  
pp. 054401
Author(s):  
Z. Chen ◽  
X. Na ◽  
C. B. Curry ◽  
S. Liang ◽  
M. French ◽  
...  

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