Water Conduits Research Articles

The Borehole Water Intakes Mathematical Models with a Branched and Circular Connection Schemes for Prefabricated Water Conduits

Borehole water intakes of underground water are widely used for water supply of agricultural towns, urban settlements, small and large cities and megacities. The number of consumers in these localities determines the number of water intakes, the number of wells, their productivity, location and connection to the prefabricated water conduits. Due to the increase in the use of underground water, the existing water intakes are being reconstructed and expanded. These works are accompanied by grouting of failed wells, their re-drilling, drilling of additional wells, re-laying of old and laying of new prefabricated water conduits. All this causes the complexity of the configuration of prefabricated water conduits due to the construction of jumpers and rings, the emergence of new wells with connection lines. Under the new conditions, in order to properly develop water intake operating modes which meet the minimum energy consumption for lifting and delivering a required volume of water to the collection-and-control tanks, to accurately choose the appropriate water lifting equipment in wells, to develop measures for intensifying water intake alongside with a forecast of their efficiency and to optimize the operation of the water intake, it is necessary to create its mathematical model that allows performing complex calculations. Water intakes with ramified prefabricated water conduits, as well as with an area scheme of the location of wells and a ring scheme of the connection of prefabricated water conduits are the most difficult object for mathematical modeling. The methods of calculating such water intakes are not sufficiently reflected in the literature, and there are no specific examples of calculation. The present article aims to clarify the methodology for calculating borehole water intakes with ramified prefabricated water conduits and with a ring scheme of their connection.

Experimental and numerical studies of boat waterjets with increased seakeeping performance

Object and purpose of research. The object of the research is a fundamentally new waterjet, intended for installation on ships of increased seakeeping performance with discrete-variable bottom deadrise. The purpose of the research is to develop and test three waterjet designs that can be installed on vessels with large deadrise, operating in severe weather conditions.
 Materials and methods. Experimental data of waterjet tests as a part of self-propelled models obtained in deep-water and cavitation test tanks of KSRC. Numerical simulation of the flow in water conduits of full-scale vessel taking into account the waterjet performance.
 Main results. As a result of the performed experimental and computational studies, the characteristics of three waterjet designs with partial-pressure water inlets were obtained: two waterjets with isolated single-elbow water ducts and inlets on the bottom section with medium deadrise, "II"design; two waterjets with combined water duct and inlets on the bottom section with maximum deadrise and double jet, “X” design; single waterjet with bifurcating two-elbow water duct and a pair of water inlets on the bottom section with maximum deadrise, “Y” design.
 Conclusion. The studies have shown that all the developed innovative waterjet designs are practically equal to conventional ones (or even better than them), and air suction creates a smooth, rather than a sharp force decrease on the impeller. The preference is given to a high-pressure water inlet with a bifurcated water inlet and a combined water conduit, because in intense waves, even if one of the inlets is aerated, the vessel will not abruptly lose speed or run off the course.

Structural details of the enzymatic catalysis of carbonic anhydrase II via a mutation of valine to isoleucine.

Kim and co-workers [IUCrJ (2020). 7, 985-994] advance our understanding of the catalytic mechanism of carbonic anhydrase II by studying a mutant V143I where the change (of one hydrophobic amino acid to another that differs by a single CH2 group) is probably the smallest alteration that can be introduced into a protein. The study was performed at high pressure in a CO2 atmosphere to visualize the bound substrate; it showed the behavior of the entrance conduit waters and the substrate alteration due to the mutation.

Absence of ice-bonded permafrost beneath an Arctic lagoon revealed by electrical geophysics.

Relict permafrost is ubiquitous throughout the Arctic coastal shelf, but little is known about it near shore. The presence and thawing of subsea permafrost are vital information because permafrost stores an atmosphere's worth of carbon and protects against coastal erosion. Through electrical resistivity imaging across a lagoon on the Alaska Beaufort Sea coast in summer, we found that the subsurface is not ice-bonded down to ~20 m continually from within the lagoon, across the beach, and underneath an ice-wedge polygon on the tundra. This contrasts with the broadly held idea of a gently sloping ice-bonded permafrost table extending from land to offshore. The extensive unfrozen zone is a marine talik connected to on-land cryopeg. This zone is a potential source and conduit for water and dissolved organic matter, is vulnerable to physical degradation, and is liable to changes in biogeochemical processes that affect carbon cycling and climate feedbacks.

The Iceland-Faroe Slope Jet: a conduit for dense water toward the Faroe Bank Channel overflow

Dense water from the Nordic Seas passes through the Faroe Bank Channel and supplies the lower limb of the Atlantic Meridional Overturning Circulation, a critical component of the climate system. Yet, the upstream pathways of this water are not fully known. Here we present evidence of a previously unrecognised deep current following the slope from Iceland toward the Faroe Bank Channel using high-resolution, synoptic shipboard observations and long-term measurements north of the Faroe Islands. The bulk of the volume transport of the current, named the Iceland-Faroe Slope Jet (IFSJ), is relatively uniform in hydrographic properties, very similar to the North Icelandic Jet flowing westward along the slope north of Iceland toward Denmark Strait. This suggests a common source for the two major overflows across the Greenland-Scotland Ridge. The IFSJ can account for approximately half of the total overflow transport through the Faroe Bank Channel, thus constituting a significant component of the overturning circulation in the Nordic Seas.

Observed Variability of the North Atlantic Current in the Rockall Trough From 4 Years of Mooring Measurements

AbstractThe Rockall Trough is one of the main conduits for warm Atlantic Water to the Nordic Seas. Ocean heat anomalies, originating from the eastern subpolar gyre, are known to influence Arctic sea ice extent, marine ecosystems, and continental climate. Knowledge of the transport through this basin has previously been limited to estimates from hydrographic sections which cannot characterize the intra‐annual and multiannual variability. As part of the Overturning in the Subpolar North Atlantic Programme (OSNAP), a mooring array was deployed in the Rockall Trough in order to obtain the first continuous measurements of transport. Here, we define the methodology and the errors associated with estimating these transports. Results show a 4‐year mean northward transport of 6.6 Sv (1 Sv = 106 m3/s) by the North Atlantic Current (NAC) in the east and interior of the Rockall Trough (2014–2018). A mean transport of −2.0 Sv (southward) is observed in the west of the basin, which could be part of a recirculation around the Rockall Plateau. The 90‐day low‐pass‐filtered transport shows large subannual and interannual variability (−1.6 to 9.1 Sv), mostly resulting from changes in the midbasin geostrophic transport. Satellite altimetry reveals the periods of low and high transport are associated with significant changes in the Rockall Trough circulation. There is a detectable seasonal signal, with the greatest transport in spring and autumn.

Methods for protecting corrosion of the inner surface of steel vitrified pipes during welding

ABSTRACT In work corrosion problems of welded steel vitrified pipelines and ways of their protection under the action of high mineral water with hydrogen sulphide (water conduits) of oil-compressor stations are considered. It is established that in order to eliminate the harmful effect of microalloying by boron of the welding seam, it is recommended to use the mentioned above welded joints of such pipelines as well as their repair. In view of the presence of a glass coating, it is recommended that extreme safety precautions be taken when installing such pipelines, in order to avoid disruption of the continuity of the glass coating.

Assessing bank dynamics of the Lower Meghna River in Bangladesh: an integrated GIS-DSAS approach

The major conduit of water and sediment discharges from the mighty Ganges-Brahmaputra-Meghna river system to the Bay of Bengal, the Lower Meghna River (LMR), experiences rapid morphological changes with significant environmental and socioeconomic consequences to the surrounding areas. This study measures the rate of bankline shifting, river widening, and change in the braiding index (BI) in the LMR over a period of 30 years (1988–2017) in order to understand the channel dynamics. To extract these parameters, we used the Digital Shoreline Analysis System (DSAS) together with other geospatial techniques on multiple satellite images taken over this period and subsequently validated the spatial outcomes through an extensive field investigation. Our findings revealed that rapid changes occurred in both banks, although at different rates, mostly due to erosion; the right bank has retreated at an average rate of 81 m/yr and the left bank at 28 m/yr, resulting in widening as well as river migration to the west. The channel widening, an overall average increase of about 49%, has been accompanied by a substantial increase in the BI, from 2.2 in 1988 to 6.4 in 2017. This study suggests that the higher erosion rate in the right bank and the consequent westward migration of the river are due to the active tectonic setting of the adjoining areas. Enormous volumes of water and sediment discharges and their periodic variations, heterogeneous bank material properties, climate change, and anthropogenic activities are also possible contributors to this bank instability. This research shows the value of implementing an integrated GIS-DSAS tool for spatiotemporal channel change investigation and could be useful in land-use planning and mitigating bank erosion in the LMR locality.

Advantages of solving the problem of turbine abrasion in the Burjar hydroelectric station by designing a sump

Existing methods are considered for designing sedimentation tanks in the Burjar hydroelectric power station to solve the problem of abrasive wear of aggregates. Weighted sediments abrade the lining of derivational and station water conduits, as well as the working elements of hydraulic turbines. In the Burjar hydroelectric power station, there is a problem associated with the abrasive wear of the units. Abrasive wear of turbines leads to a significant drop in their efficiency, and therefore, a decrease in the power and energy generation of a hydroelectric power station, a reduction in the service life of hydroturbine equipment, and a fragment of wear. For the design of the sump, geological and hydrological information was collected about the Burjar hydroelectric power station. The sump is projected onto the derivation channel of the Burjar hydroelectric station. To determine the size of the sump, laboratory analysis of the water of the Burjar hydroelectric station was carried out. The hydraulic calculation of the sump includes determining the main dimensions of the chamber, sediment volume, flushing turbidity, and siltation time of the dead chamber volume with sediment. The calculation is described by the method of academician E.A. Zamarin. According to the method of E.A. Zamarin, the width of the chamber is 9.6 m and the length of the chamber is 73 m. These results are accurate and they were used during the design of the sump.

Laboratory and numerical simulations of spatio-temporal variability of water exchange between the fissures and conduits in a karstic aquifer

Fissures and conduits are main void of karstic aquifer. Karst aquifers are highly vulnerable to contamination as water exchange between fissuresystem andconduitsystem greatly influences the karstification of limestone terrains, heterogeneity of karstic aquifer, and spring flow regime. A two-dimensional tank model was constructed, and a corresponding numerical model (MODFLOW-2005 Conduit Flow Process Mode 1, CFPM1) was developed to explore the effects of rainfall intensity and intrinsic structure of karst system (hydraulic conductivity of fissures and conduit diameter) on conduit-matrix water exchange. Nine different scenarios were designed to quantitatively simulate the spatial and temporal variability of water exchange between the fissures and conduits. The study reproduced the area of fissure water recharging to conduit (recharge zone), the area of conduit water discharging to fissure water (discharge zone) and the area of fissure water moving laterally (transport zone) in both physical model and numerical model. The results from rainfall scenarios show a relatively stable ratio of exchange zone (recharge zone and discharge zone) with increasing rainfall intensity, indicating that conduit-matrix water exchange is not sensitive to rainfall intensity, and conduit water discharging to fissure water is just a short-term phenomenon. It is also found that an increase in hydraulic conductivity of fissure system enhances extensiveness of water transport, but restrains conduit-matrix water exchange. However, the enlargement of conduit can prompt the extent of conduit-matrix water exchange. A positive feedback between the extent of conduit-matrix water exchanges and karstification can be confirmed. These findings might be essential for better understanding groundwater flow dynamics in karst aquifers.

Emission of CO2 and CH4 from a multi-ditches system in rice cultivation region: Flux, temporal-spatial variation and effect factors

Man-made multi-level ditches system is designed to irrigate, drain and collect runoff from surrounding fields. It is not only the conduit of water and field carbon, but also the linear-like wetland with complex carbon cycling. However, the contribution of ditches system to CO2 and CH4 emission has rarely been assessed. To understand the emission pattern of CO2 and CH4 from ditches, this study investigated the emission fluxes of CO2 and CH4 in a three-level ditches system in Chengdu Plain, China. The results showed that the emission of CO2 and CH4 ranged from 70.38 to 950.40 mg C m−2 h−1 and 6.51–74.99 mg C m−2 h−1, respectively, and was higher in spring and summer than other seasons in all ditches (P < 0.05). On the other hand, the emission of CO2 and CH4 increased along with the decreasing ditches size. Besides, it is found that the precipitation, water table depth and water DO concentration might contribute to the emission of CO2, while CH4 was possibly influenced by precipitation, water table depth, temperature, water DO and DOC concentration. Moreover, it is suggested that terrestrial external input and in-situ metabolism might be the main sources of C emission, and in-situ source might largely contribute to CH4 emission. To reduce the C emission, it is necessary to improve fertilization and irrigation methods, limit soil pollutants transferring into ditches, and frequently dredge sediments in future.

The effects of morphometric elements of the channel on hydraulic resistance of machine channels of pumping stations

Presents the results of hydraulic studies in pressureless and pressure water conduits, the results of which showed that the dependences obtained for calculating the hydraulic resistance in round pressure pipes cannot be distributed without the corresponding adjustments of pressureless channels (provided that the diameter of the pipe is replaced in the corresponding calculations with a value where hydraulic radius). In particular, it follows (and this is confirmed by the data of the corresponding experimental studies published in the literature) that in the case of pressureless channels, the pressure loss coefficient, and therefore the pressure loss, depends not only on the relative roughness and Reynolds number, but also on the shape of the cross section the channel. Moreover, if for hydraulically smooth pressureless channels this dependence can be considered to a first approximation clarified, then for channels whose wetted surface is characterized by the presence of a certain roughness, the question of its influence, as well as the shape of the channel cross section on the pressure loss, is far from roughly approximate solution. The paper also considers the general equation of fluid motion in pressureless channels and the functional dependences of the coefficient of hydraulic friction on the Reynolds number, relative roughness, and on the shape of the living section of the channel; resistance formulas are first for the simplest with respect to the cross-sectional shape of the channels (round and infinitely wide rectangular), and then for channels with a more complex cross-sectional shape. To take into account the effect (on the pressure loss) of the channel cross-sectional shape and the presence of a flow with a free surface in it, additional correction factors are introduced (using the hydraulic radius concept) as well as new dependencies and formulas for determining the hydraulic friction coefficient are given, s taking into account the influence of morphometric elements of the channel on the hydraulic resistance of the machine channels of pumping stations.

Drinking and Water Handling in the Medaka Intestine: A Possible Role of Claudin-15 in Paracellular Absorption?

When euryhaline fish move between fresh water (FW) and seawater (SW), the intestine undergoes functional changes to handle imbibed SW. In Japanese medaka, the potential transcellular aquaporin-mediated conduits for water are paradoxically downregulated during SW acclimation, suggesting paracellular transport to be of principal importance in hyperosmotic conditions. In mammals, intestinal claudin-15 (CLDN15) forms paracellular channels for small cations and water, which may participate in water transport. Since two cldn15 paralogs, cldn15a and cldn15b, have previously been identified in medaka, we examined the salinity effects on their mRNA expression and immunolocalization in the intestine. In addition, we analyzed the drinking rate and intestinal water handling by adding non-absorbable radiotracers, 51-Cr-EDTA or 99-Tc-DTPA, to the water. The drinking rate was >2-fold higher in SW than FW-acclimated fish, and radiotracer experiments showed anterior accumulation in FW and posterior buildup in SW intestines. Salinity had no effect on expression of cldn15a, while cldn15b was approximately 100-fold higher in FW than SW. Despite differences in transcript dynamics, Cldn15a and Cldn15b proteins were both similarly localized in the apical tight junctions of enterocytes, co-localizing with occludin and with no apparent difference in localization and abundance between FW and SW. The stability of the Cldn15 protein suggests a physiological role in water transport in the medaka intestine.

An Approach to the Restoration of Metal Water Conduits of Hydraulic Structures

Issues related to the search for effective technical solutions for the restoration of pressure metal water conduits of hydraulic structures are considered. Findings demonstrating the relevance of using polymer composites as external reinforcement systems for restoration are presented. Recommendations on the integration of technologies for the restoration of water conduits are given.

ПРОБЛЕМЫ КАЧЕСТВА ПИТЬЕВОЙ ВОДЫ ЗАПАДНОЙ ЧАСТИ КРЫМА

Introduction. Until 2014, water supply in Sevastopol city and its municipal districts was combined due to its own surface and underground waters as well as a water conduit running from the Mezhgornoye reservoir located in the Saksky district and filled with the Dnieper waters of the North Crimean Canal. After 2014, this source was shut off. Therefore, it became important to conduct a comparative analysis of the quality of drinking water supplied to the settlements of this territorial entity. Purpose of the study: The study is aimed to assess the quality of drinking water and perform its analysis in Sevastopol city and nearby settlements, taking into account the increase in water intake from rivers and underground sources in recent years. Methods. Objects of the study are surface and underground water supply points, and drinking water for consumers. We used standard methods for the analysis of drinking water with an assessment of its physical, chemical and sanitary-bacteriological indicators using analysis of variance (AoV) methods. Water quality was assessed by the specific combinatorial index of water pollution. Using GIS technologies, maps were built to visualize a number of indicators: chemical oxygen consumption and data on the water pollution complexity coefficient at the stage when consumers receive water from the central water supply system (for all municipal districts). Results. It was established that sanitary and microbiological indicators of tap water quality — by the total microbial count, total coliform bacteria and thermo-tolerant coliform bacteria — immediately before being fed to the central water supply system in the Southern and Northern districts of Sevastopol, did not exceed sanitary standards. Due to the considerable length of the distribution networks and their high deterioration, secondary pollution of drinking water is currently taking place. In a number of municipal districts, it was revealed that the key indicators being assessed exceeded the norms of the State Sanitary Rules and Regulations. For the first time, with the help of GIS technologies in the ArcGis 10.4 software shell, specific ranks of drinking water pollution levels were distinguished for individual municipal districts, which made it possible to visualize the dynamic characteristics of polluting ingredients taking into account their territorial affiliation.

Digital clone for penstock fatigue monitoring

In Switzerland, most of the hydro power plants were installed between 1950 and 1970. These power plants play an important role for electrical power network stability through their operational flexibility and ability to provide ancillary services. These services lead to frequent start and stop sequences, as well as continuous power variations inducing transient pressures in the water conduits. Due to electricity market recent evolutions, existing hydropower plants are subject to new operating conditions and sequences which were not foreseen during the design phase. This significant increase of load variations enhances fatigue problems by soliciting the penstock faster than originally expected. While loading spectra are the fundamental input for any fatigue assessment procedure, they are often difficult, if not impossible, to quantify accurately. In this paper, we present how the implementation of a digital clone of the power plant, namely the Hydro-Clone real-time simulation monitoring system, can be used to fill this gap. By replicating the hydraulic transients of the powerplant, the digital clone enables real-time knowledge of the pressure variations throughout the water conduits. This feature is used to implement a fatigue module in Hydro-Clone by monitoring the penstock level of solicitation, based on the accumulated damage during its past and future operations. To validate this approach, stresses related to pressure variations are measured in situ by installing strain gages on the penstock of the 200 MW La Bâtiaz hydropower plant, owned by Electricité d’Emosson SA, and compared to the simulated values. Our results reveal the considerable impact of the supply of ancillary services on penstock fatigue wear.

About the features of the water-bodies monitoring at the surface water-intake facilities of the oil fields of the Far North

The practice of the exploitation of hydrocarbon deposits of the Far North shows that despite the complexity and interdependence of natural and man-made conditions, the design of structures uses a certain set of solutions related to the characteristics of the area. The main fact is that all linear objects are designed in one corridor, at the same time, pipelines (oil pipelines, water conduits) are designed for ground laying on piles, areal objects (infrastructural sites) on the embankment with the preservation of the soil and vegetation layer at the base of the embankment. In addition, speaking about the field development or the transport of the product, unreasonably little attention is paid to the objects that ensure the operation of the main objects in normal mode. Such objects, in particular, are the water conduits and water-intake structures that provide an uninterrupted supply of water of the desired quality and quantity on the area of support base of the field of deposits. Despite the rather strict environmental legislation, it is impossible to take into account all the factors of negative impact on the environment, it is even more difficult to monitor the effect of a complex of these factors, and especially the interaction of all objects, processes and phenomena within the current natural and technical system.

A preliminary investigation of the properties of potassium magnesium phosphate cement-based grouts mixed with fly ash, water glass and bentonite

Water inflow in a karst area has the characteristics of a large water volume and a fast flow rate, which makes the water inrush of a karst conduit flow extremely difficult to treat. Ordinary inorganic grouting materials have weak bonding with the interface, long initial and final setting time intervals and high loss rates of dynamic water filling. Phosphate cement has good interfacial bonding and instantaneous final setting after the initial setting, which is suitable for dynamic water conduit plugging. In this work, we developed anti-scouring grouts based on light-burned magnesia, potassium dihydrogen phosphate, Class F fly ash, water glass, and bentonite. A condensate based on potassium magnesium phosphate cement (MKPC) is formed using Class F fly ash (0–30%) to replace some of the MgO and KH2PO4. Then, the three materials form a cementitious material system. The water-cement ratio is 1:1 and is then modified with bentonite (5%) and water glass (0–6%). The basic properties of the grouts were studied by measuring the setting time, viscosity, compressive strength (after 3 d, 7 d, and 28 d), and flow distance. The microscopic properties of the hardened stone were studied by using both X-ray diffraction (XRD) and scanning electron microscope (SEM). The experiments show that the molar ratio of MgO to KH2PO4 (M/P) along with the water glass and fly ash contents play a significant role in the setting time, compressive strength, and viscosity of the grouts. The addition of fly ash can reduce the fluidity of the grouts and the early strength; however, the 28-day compressive strength of the grouting material mixed with 30% class F fly ash is higher than that of the grouting material mixed with 10% and 20% Class F fly ash. Water glass can reduce the setting time and fluidity of the grouts and can increase the strength of the grouts.

Effects of antecedent moisture and macroporosity on infiltration and water flow in frozen soil

AbstractInfiltration into frozen soil plays an important role in soil freeze–thaw and snowmelt‐driven hydrological processes. To better understand the complex thermal energy and water transport mechanisms involved, the influence of antecedent moisture content and macroporosity on infiltration into frozen soil was investigated. Ponded infiltration experiments on frozen macroporous and non‐macroporous soil columns revealed that dry macroporous soil produced infiltration rates reaching 103 to 104 mm day−1, two to three orders of magnitude larger than dry non‐macroporous soil. Results suggest that rapid infiltration and drainage were a result of preferential flow through initially air‐filled macropores. Using recorded flow rates and measured macropore characteristics, calculations indicated that a combination of both saturated flow and unsaturated film flow likely occurred within macropores. Under wet conditions, regardless of the presence of macropores, infiltration was restricted by the slow thawing rate of pore ice, producing infiltration rates of 2.8 to 5.0 mm day−1. Reduced preferential flow under wet conditions was attributed to a combination of soil swelling, due to smectite‐rich clay (that reduced macropore volume), and pore ice blockage within macropores. In comparison, dry soil column experiments demonstrated that macropores provided conduits for water and thermal energy to bypass the frozen matrix during infiltration, reducing thaw rates compared with non‐macroporous soils. Overall, results showed the dominant control of antecedent moisture content on the initiation, timing, and magnitude of infiltration and flow in frozen macroporous soils, as well as the important role of macropore connectivity. The study provides an important data set that can aid the development of hydrological models that consider the interacting effects of soil freeze–thaw and preferential flow on snowmelt partitioning in cold regions.

Application of Schlumberger Method for Characterization of Soil

A nowadays, geo-environmental study such as soil contamination analysis, electrical properties of soil, and geo-technical centrifuge modeling needs a characterization of soil. This will help in estimation of soil properties, mathematical and physical modeling, field investigation and some other detailed phenomenon. In this study, we used a Schlumberger method for characterization of soil in the water conduit of village Visarpani, near Mainpat block of Surguja district of Chhattisgarh, India. In this conduit, water stream climbs itself towards uphill with the slope of 450 and travels distance about 150 meters in East to West direction and after turns towards downhill in North to South direction. Experimentally calculated Schlumberger resistance used in the theoretical calculations for finding resistivity and conductivity of soil and then predicted the soil characteristics at different intervals. This study showed that towards uphill resistivity is decreasing and conductivity is increasing regarding distance intervals.