Reduction In Flow Rate Research Articles

Numerical Investigation of Liquid Flow Behaviors through Closed Rough Fractures in the Self-Propped Shale Formation

The surface morphology of fractures formed by hydraulic fracturing is usually rough. The roughness of the fracture surface is the main reason the actual fracture conductivity deviates from the ideal flat plate model result. In this paper, based on the three-dimensional reconfiguration of actual rough hydraulic fractures, a randomly generated geometric model of a micro-convex body with a rough fracture surface is used as an example of a hydraulic fracture in a shale reservoir. Assuming that the flow in the fracture conforms to the laminar flow pattern, the velocity and pressure fields of the fluid flow on the fracture surface are solved by the finite element method. The effects of micro-convex body size, uniformity, density, and shape on the non-uniform flow of the rough fracture surface are analyzed. The three-dimensional model shows that the average velocity is minimum in the near fully closed fracture. The fluid bypasses the micro-convex body during the flow, forming multiple nonlinear flow regions. The streamlined tortuosity increases with the density and size of the micro-convex bodies and depends on the distribution of the micro-convex areas. The bypassing accelerates the pressure drop and slows down the flow rate. The greater the degree of micro-convex body aggregation, the more significant the decrease in flow velocity. The more locations where the curvature of the micro-convex edge is not zero, the more nonlinear flow zones can significantly reduce the flow rate and thus affect oil and gas production. Targeted optimization of the proppant placement pattern to make the trailing part of the micro-convex body as close to streamlined as possible can reduce the nonlinear flow area and slow down the flow rate reduction.

Effect of sponge city construction on urban waterlogging reduction in semi-humid areas of China

Abstract Urban waterlogging frequently occurs in semi-humid areas due to the short duration of heavy rainfall in summer and the high rates of subsurface hardening caused by high-intensity urban development. To solve the problem of urban waterlogging, China has launched the construction of ‘sponge cities’ and made some progress, but there is still a lack of comprehensive consideration of the functional types and spatial layout of low impact development (LID) facilities. Qian'an, a city of Hebei Province, is one of the first sponge city pilot cities in China. This paper focuses on Yanshan South Road and its surrounding areas, a historical waterlogging section of Qian'an city. Four common LID measures (sunken green space (SG), bioretention ponds (BP), infiltration ponds (IP), and reservoirs (RE)) in two function types are selected and combined through centralized (CE) and decentralized (DE) different spatial layouts, a total of 80 design scenarios are proposed. Then, using the storm water management model (SWMM) to calculate the effect of each scheme on peak flow reduction under different rainfall return periods. The results showed that all LID scenarios can effectively alleviate the urban waterlogging problem, among which the schemes of DE-SG-BP (1:1), DE-IP-SG (1:1), DE-SG-IP (3:1), DE-SG-IP (1:3), and DE-SG-BP (3:1) had the highest peak flow reduction rate, up to 95.46%. The schemes of CE-RE-IP (3:1) and CE-IP-RE (3:1) had better hydrological performance in occupying less surface space, with a peak flow reduction rate of 8.68% per square meter. Therefore, the distributed layout combined with infiltration LID facilities and storage LID facilities can be used in urban built-up areas with limited land use conditions, which has a more obvious effect on reducing waterlogging.

Antarctic Bottom Water Warming and Circulation Slowdown in the Argentine Basin From Analyses of Deep Argo and Historical Shipboard Temperature Data

AbstractA decadal warming trend of 2.1 (±0.2) m°C yr−1 in Antarctic Bottom Water within the western Argentine Basin is found by comparing Deep Argo temperature profiles from 2021 to 2022 to nearby historical shipboard data from 1972 to 1998. This trend is similar in magnitude, but about 10 times more certain, than a previously published trend in the eastern Argentine Basin estimated using repeat hydrographic section data (World Ocean Circulation Experiment Section A16S) from 1989, 1995, and 2014. The present analysis also detects a warming rate in the coldest water entering the basin about double that in the interior. The observed reduction in deep meridional temperature gradient indicates a reduction in geostrophic shear, consistent with a reduced flow rate, and transport, of the coldest, deepest water entering the basin. The falling isotherms in the basin are consistent with an 0.6 × 106 m−3 s−1 reduction in inflow of the coldest waters to the basin.

Numerical study on the extinction dynamics of partially premixed meso-scale methane-air jet flames with hydrogen addition

In this paper, a model of partially premixed jet flames that sustained above a meso-scale short tube was established for an individual flame port of domestic gas stoves. The effects of hydrogen addition (volume ratio β = 0%, 10%, 20%, 30%) on the extinction dynamics of CH4-air jet flames were numerically investigated. It is found that flame oscillation occurs once (β = 10% and 20%) or twice (β = 30%) in the extinction process. Moreover, the larger of β, the longer the extinction process can sustain. Analysis was performed in terms of both chemical effect and thermal effect. As to the chemical effect, in the first place, the reaction rate decreases as the inlet velocity is reduced. As a result, the consumption rate of O2 will be less than the supply rate from the incoming mixture, which makes the O2 concentration in the flame center increase. On the other hand, the amount of H radicals increases with the increase of β, and when the O2 content at the flame center reaches a “critical point”, the key elementary reaction “H + O2 ↔ O + OH” will be enhanced and consequently the total reaction rate will also be intensified. After that, the consumption rate of O2 will be larger than the supply rate due to the reduced flow rate of incoming mixture. The total heat release rate will decrease sharply and extinction occurs. As regards the thermal effect, it is revealed that heat recirculation effect (indirect preheating effect) lags behind the variation of the reaction zone (i.e., flame), thus, it has a negligible impact on flame oscillation. In contrast, the preheating temperature in the vicinity of flame front (named as “direct preheating effect”) exhibits a similar variation tendency with the total heat release rate of the flame. And the larger of β, the more remarkable of the direct preheating effect can be. In summary, due to the chemical effect and thermal effect caused by hydrogen addition, the flame can survive for a longer time with fluctuation during the extinction process.

From faceted nanoparticles to nanostructured thin film by plasma-jet redox reaction of ionic gold

Cold-atmospheric plasma-assisted deposition has emerged as an efficient technique for synthesising gold nanoparticles (AuNPs). Here, a plasma-vapour interaction is used for the simultaneous reduction and deposition of AuNPs from an inorganic precursor (HAuCl4). As surface analyses suggest, plasma input power plays an important role in reduction efficiency, whereas argon gas flow rate reduction leads to the formation of smaller particles. This study demonstrates that the presence of ethanol in the reactive mixture of gold promotes improved reduction of gold to nanostructures owing to their volatile properties. A systematic investigation of plasma and the deposited nanostructures reveals that the reduction is mainly caused by the free electrons and in-situ formation of hydrogen peroxide inside plasma. Our method demonstrates that nanostructured thin film can be created within 5 min by controlling plasma parameters. Deposited AuNPs feature advanced plasmonic surface-enhanced Raman scattering responses, tested with Raman marker Rhodamine R6G, enabling their use as a potential substrate for fast and reliable optical analytical biochemical sensing.

Deep Single-Shot NanoLC-MS Proteome Profiling with a 1500 Bar UHPLC System, Long Fully Porous Columns, and HRAM MS.

This study demonstrates how the latest ultrahigh-performance liquid chromatography (UHPLC) technology can be combined with high-resolution accurate-mass (HRAM) mass spectrometry (MS) and long columns packed with fully porous particles to improve bottom-up proteomics analysis with nanoflow liquid chromatography–mass spectrometry (nanoLC-MS) methods. The increased back pressures from the UHPLC system enabled the use of 75 μm I.D. × 75 cm columns packed with 2 μm particles at a typical 300 nL/min flow rate as well as elevated and reduced flow rates. The constant pressure pump operation at 1500 bar reduced sample loading and column washing/equilibration stages and overall overhead time, which maximizes MS utilization time. The versatility of flow rate optimization to balance the sensitivity, throughput with sample loading amount, and capability of using longer gradients contributes to a greater number of peptide and protein identifications for single-shot bottom-up proteomics experiments. The routine proteome profiling and precise quantification of >7000 proteins with single-shot nanoLC-MS analysis open possibilities for large-scale discovery studies with a deep dive into the protein level alterations. Data are available via ProteomeXchange with identifier PXD035665.

Freeze-thaw cycles alter soil hydro-physical properties and dissolved organic carbon release from peat

The ongoing climate warming is likely to increase the frequency of freeze-thaw cycles (FTCs) in cold-temperate peatland regions. Despite the importance of soil hydro-physical properties in water and carbon cycling in peatlands, the impacts of FTCs on peat properties as well as carbon sequestration and release remain poorly understood. In this study, we collected undisturbed topsoil samples from two drained lowland fen peatlands to investigate the impact of FTCs on hydro-physical properties as well as dissolved organic carbon (DOC) fluxes from peat. The soil samples were subject to five freeze-thaw treatments, including a zero, one, three, five, ten cycles (FTC0, FTC1, FTC3, FTC5, and FTC10, respectively). Each FTC was composed of 24 h of freezing (−5°C) and 24 h of thawing (5°C) and the soil moisture content during the freeze-thaw experiment was adjusted to field capacity. The results showed that the FTCs substantially altered the saturated hydraulic conductivity (Ks) of peat. For peat samples with low initial Ks values (e.g., < 0.2 × 10−5 m s−1), Ks increased after FTCs. In contrast, the Ks of peat decreased after freeze-thaw, if the initial Ks was comparably high (e.g., > 0.8 × 10−5 m s−1). Overall, the average Ks values of peatlands decreased after FTCs. The reduction in Ks values can be explained by the changes in macroporosity. The DOC experiment results revealed that the FTCs could increase DOC concentrations in leachate, but the DOC fluxes decreased mainly because of a reduction in water flow rate as well as Ks. In conclusion, soil hydraulic properties of peat (e.g., Ks) are affected by freezing and thawing. The dynamics of soil hydraulic properties need to be explicitly addressed in the quantification and modelling of the water flux and DOC release from peatlands.

Energy saving in distillation by combining vortex contact device and thermal effects

• Energy efficiency assessment of the thermal distillation in the column apparatuses is presented. • Heat extra removed from the upper tray of the column leads to a decrease in heat flows by 9–12%. • Vortex contact devices provide an increase in the mole fraction of the light-volatile component in the liquid by 5.61%. Thermal effects are proposed to improve the efficiency of heat and mass transfer phenomena in distillation columns. The new design of the vortex contact device is developed. The paper investigates a combined use of the vortex devices that act as the contact stages of the distillation column and heat removal from the upper contact stage. Theoretical results on the distribution of vapor and liquid flows on each tray of the vortex device are obtained. The mass flow rate of the liquid phase as a result of the partial condensation of vapors is determined based on the amount of heat removed and the location of the tray with additional heat removal. A reduction in the mass flow rate of reflux during thermal distillation is experimentally established. The dependence of the average Murphree tray efficiency of the vortex contact stage is obtained depending on the reflux ratio at thermal distillation, which is confirmed experimentally. Experimental study shows an increase in the average efficiency of the stage by 10.6% compared to the adiabatic column without heat removal. A distillate mass fraction of 0.884 in the liquid phase is achieved at the outlet of the column when using 10 vortex contact stages and the working reflux ratio of 1.83. The comparative analysis of the use of the developed vortex contact devices in the thermal distillation process is performed in terms of the separation quality of the ethanol–water mixture, energy costs for the supply, and removal of heat.

Effect of transcatheter edge-to-edge repair device position on diastolic hemodynamic parameters: An echocardiography-based simulation study.

BackgroundTranscatheter edge-to-edge repair (TEER) has developed from innovative technology to an established treatment strategy of mitral regurgitation (MR). The risk of iatrogenic mitral stenosis after TEER is, however, a critical factor in the conflict of interest between maximal reduction of MR and minimal impairment of left ventricular filling. We aim to investigate systematically the impact of device position on the post treatment hemodynamic outcome by involving the patient-specific segmentation of the diseased mitral valve.Materials and methodsTransesophageal echocardiographic image data of ten patients with severe MR (age: 57 ± 8 years, 20% female) were segmented and virtually treated with TEER at three positions by using a position based dynamics approach. Pre- and post-interventional patient geometries were preprocessed for computational fluid dynamics (CFD) and simulated at peak-diastole with patient-specific blood flow boundary conditions. Simulations were performed with boundary conditions mimicking rest and stress. The simulation results were compared with clinical data acquired for a cohort of 21 symptomatic MR patients (age: 79 ± 6 years, 43% female) treated with TEER.ResultsVirtual TEER reduces the mitral valve area (MVA) from 7.5 ± 1.6 to 2.6 ± 0.6 cm2. Central device positioning resulted in a 14% smaller MVA than eccentric device positions. Furthermore, residual MVA is better predictable for central than for eccentric device positions (R2 = 0.81 vs. R2 = 0.49). The MVA reduction led to significantly higher maximal diastolic velocities (pre: 0.9 ± 0.2 m/s, post: 2.0 ± 0.5 m/s) and pressure gradients (pre: 1.5 ± 0.6 mmHg, post: 16.3 ± 9 mmHg) in spite of a mean flow rate reduction by 23% due to reduced MR after the treatment. On average, velocities were 12% and pressure gradients were 25% higher with devices in central compared to lateral or medial positions.ConclusionVirtual TEER treatment combined with CFD is a promising tool for predicting individual morphometric and hemodynamic outcomes. Such a tool can potentially be used to support clinical decision making, procedure planning, and risk estimation to prevent post-procedural iatrogenic mitral stenosis.

SIALOMETRIC CHANGES IN PATIENTS UNDER CHEMOTHERAPY TREATMENT: A NARRATIVE REVIEW

<h3>Objectives</h3> The objective of this study was to summarize the theoretical contributions concerning the sialometric changes occurring in patients during chemotherapy treatment. <h3>Study Design</h3> This study is a narrative review of the literature through secondary data analysis. The literature survey was carried out from March to April 2021 using the Virtual Health Library, Scielo, and PubMed as the databases and with the descriptors "Salivary Glands," "Hyposalivation," "Cancer," and "Chemotherapy." The included studies were published in the previous 10 years in any language. <h3>Results</h3> Chemotherapy was responsible for altering salivary flow in patients due to the high sensitivity of oral structures to the toxic effects of chemotherapy drugs. The studies used the tests of unstimulated sialometry and stimulated sialometry for the sialometric evaluation of patients. The results showed a reduction in the average salivary flow rate and high salivary viscosity. Changes in pH were also observed and decreased during and after treatment. The behavior in children undergoing antineoplastic treatment was opposite to that found in adults. The salivary flow and salivary pH remained the same during chemotherapy. <h3>Conclusions</h3> Adult patients developing antineoplastic therapy using chemotherapy drugs have a marked reduction in salivary flow and salivary pH.

Dynamic coronary CT Angiography-Estimated coronary flow in Non-Obstructive, Plaque-free coronary Arteries: Association with dyslipidemia and diabetes.

Rationale and ObjectivesIn this study, we implemented dynamic coronary CT angiography (CCTA) in order to estimate the coronary flow rate in morphologically normal coronary arteries as well as to identify factors affecting the coronary flow rate.Materials and MethodsWe retrospectively enrolled 95 consecutively presenting patients without stenosis or plaque in their major coronary arteries on CCTA conducted with a 320-detector scanner (mean age, 57 years; 43 % men). Time-attenuation curves of the distal sites of the major coronary arteries and the aortic root were extracted from dynamic CCTA data. Coronary flow rate, an indicator of coronary blood flow, was calculated via a convolution-integration method integrating the two curves. Patients with dyslipidemia were divided according to the presence or absence of familial hypercholesterolemia (FH) as well as according to the receipt of statin therapy.ResultsWe found that the coronary flow rate was statistically significantly lower in statin-naïve patients with dyslipidemia (n = 27, 0.56 ± 0.10) than in patients without dyslipidemia (n = 32, 0.64 ± 0.10, p = 0.0013). In FH (n = 26), the coronary flow rate was statistically significantly lower in statin-naïve patients (n = 7, 0.65 ± 0.08) than in those taking statins (n = 19, 0.72 ± 0.10, p = 0.0221). Coronary flow rate likewise exhibited a statistically significant negative correlation with hemoglobin A1c (Pearson r, −0.437; p = 0.0003), but no correlation with other coronary risk factors. The coronary flow rate was statistically significantly lower in patients with diabetes (n = 14, 0.55 ± 0.10) than in those without diabetes (n = 81, 0.61 ± 0.11, p = 0.0461).ConclusionWe found a reduction in coronary flow rate in patients with statin-naive dyslipidemia and diabetes, even within morphologically normal coronary arteries.

Aerodynamic influences on the outer ash deposition rates during oxy-coal combustion

Second generation oxy-combustion and load following operations are accompanied by a significant (60–70%) reduction in combustor flue gas flow rates when compared to baseload operation. Understanding the aerodynamic influences on the fly-ash particle deposition characteristics during these novel operational scenarios are critical towards anticipating operational challenges. To fill this void, a novel Computational Fluid Dynamic (CFD) methodology in conjunction with an ash deposition module was used to model the outer ash deposition process coal during combustion of coal in AIR and O2/CO2 (70/30 vol%, OXY70) oxidizer compositions and the predictions were compared with measurements. The measured fly-ash particle size distributions (PSD) were employed as inputs to represent the particle Stokes numbers near the deposition surface accurately and the capture criterion was based on a recently proposed particle viscosity and kinetic energy (PKE) based formulation. Prediction sensitivities to the particle viscosity model and fly-ash PSD were also assessed. Deposition rate predictions in AIR were in excellent agreement with the measurements. The deposition rate enhancement (OXY70/AIR) across all scenarios were in the range 2.8–3.3 which was in reasonable agreement with the measured values of 2.1–2.4. Predicted capture efficiencies were nearly 100% across all scenarios. The calculations were repeated by employing the corresponding fly-ash composition information rather than the bulk-ash compositions and did not alter the predictions significantly. The study therefore supports the hypothesis that ash deposition rates in these novel operational scenarios are likely to be dominated by PKE.

Numerical study on the straight, helical and spiral capillary tube for the CO2 refrigerant

A numerical study has been carried out for straight, spiral and helical capillary tubes and their performance has been compared with CO2 refrigerant. The numerical models are developed based on the fundamental conservation principles of mass, momentum, and energy. Within this, outer loop, the ordinary differential equations are solved from the inlet to the exit of the capillary tube. The study has been carried out to calculate the mass flow rate by bisection method where the mass is iteratively calculated at the specified capillary length or vice versa. In-house coding programming employs the finite difference approach for numerical solutions. The characterization of the capillary tube has been done by calculating the length for the given mass or by calculating mass for the given length. The comparison of the straight capillary with helical capillary tube (50 mm coil diameter) and spiral capillary tube (50 mm pitch) has been reported. For a change in tube diameter, surface roughness, and length, the percentage reduction in mass flow rate in capillary tubes (straight, helical, and spiral) is calculated. The percentage reduction in mass in a helical capillary tube compared to the straight capillary tube is about 7–9 %. The percentage reduction in mass in a spiral tube compared to the straight capillary tube is nearly 23–26 %. Additionally, the percentage reduction in mass in a spiral tube compared to the helical capillary tube is almost 17–19 %. Additionally, the percentage reduction in length in a spiral tube compared to straight capillary tube ranges from 37 % to 43 %. Similarly, the percentage reduction in length in a spiral tube compared to helical capillary tube is ranging from 25 % to 32 %

Turbulence dissipation of leakage flow in supercritical CO2 labyrinth seals

Supercritical CO2 (S-CO2) leakage through seals significantly reduces the efficiency of turbomachinery. Improving the labyrinth seal structure is potentially the key to the reduction of the leakage flow rate, but its application is greatly limited by the uncertainties of supercritical CO2 turbulent flow inside the turbomachines with irregular chambers. In this work, we numerically investigated the S-CO2 flow field and dissipation rate of turbulence kinetic energy in stepped labyrinth seals. The RANS method and hexahedral structural mesh were employed. The look-up table containing the real gas properties of carbon dioxide was created and imported into the flow solver. The developed numerical method was validated by experiment results and proved its applicability. We have discovered that the fully developed rotating vortices inside each chamber of the turbomachine significantly increase the turbulent dissipation rate and decrease the fluid carried energy, thus reducing the leakage flow rate. With the seal clearance increasing form 0.5 mm–1.3 mm at pressure ratio π = 0.7, the vortices development is gradually limited, causing the decrease of turbulent dissipation rate. The leakage rate is found to be heavily dependent on the distance between the seal tip and step. The increase in this distance from 2 mm to 6 mm results in greater space for the continued development of the vortices within the first chamber, thus the enhancement of the turbulent dissipation rate of fluid. Therefore, we defined a geometry coefficient, (δ-b)/s, and analyzed its effects on turbulent dissipation rate and leakage flow rate. With this geometry coefficient increases from 2.8 to 11.2 at π = 0.7, the maximum turbulent dissipation rate increases from 7.09 × 107 to 1.23 × 108 and the leakage flow rate decreases from 3.98 × 10−2 kg/s to 1.62 × 10−2 kg/s. An improved leakage model characterizing seal geometry, gas properties and compressibility effects was proposed.

Possible Role of Ppar-Alpha Agonist in Attenuated Cardioprotective Effects of Ischemic Postconditioning in Diabetic Rat Heart

Background: It has been accounted for that infarct size reduction and cardioprotective effects of Ischemic Postconditioning (IPOC) have been abrogated in few pathological conditions including diabetes. Peroxisome Proliferator-Activated Receptor-Alpha (PPAR-Alpha) agonist is known to have cardioprotective effect. Therefore, the current examination researched the possible role of PPAR-Alpha Agonist in Attenuated Cardioprotective Effects of Ischemic Postconditioning in Diabetic Rat Heart. Materials and Methods: Rats were injected Alloxan Monohydrate (150/mg/kg/i.p) single dose to produced diabetes. Isolated Langendorff ’s perfused normal and diabetic rat hearts were subjected to global ischemia for 30 min followed by reperfusion for 120 min. Coronary effluent was analyzed for Lactatedehydogenase (LDH) and Creatine Kinase (CK) release to evaluate the extent of cardiac injury. The oxidative stress in heart was evaluated by measuring Thiobarbituric Acid Reactive Substances (TBARS), superoxide dismutase (SOD) generation and reduced form of glutathione. Result: In the current investigation, Ischemia-reperfusion (I/R) induced oxidative stress by increasing TBARS, superoxide anion generation and the decreased form of glutathione in normal and diabetic rat heart. Moreover, I/R induced myocardial injury, was evaluated in terms of increase in, LDH and CK release in coronary effluent, and reduction in coronary flow rate in normal and diabetic rat heart. The diabetic rat heart showed enhanced I/R induced myocardial injury with high extent of oxidative stress as compared with normal rat heart subjected to I/R Six episodes of IPOC afforded cardioprotection against I/R induced myocardial injury in normal rat heart as assessed in terms of improvement of coronary flow rate and decrease of LDH, CK and oxidative stress. On other hand, IPOC mediated myocardial protection against I/R injury was nullified in diabetic rat heart. Fenofibrate (5µM), a selective agonist of PPAR alpha, its administration markedly restored the Cardioprotective potential of IPOC in diabetic rat heart. Conclusion: The current investigation presumed that, the high degree of oxidative stress produced in diabetic rat heart during reperfusion and resulting inactivation of PPAR alpha receptor might be responsible for abolishing the Cardioprotective potential of IPOC against I/R induced myocardial injury

Preliminary Evaluation of a Blast Sprayer Controlled by Pulse-Width-Modulated Nozzles.

Precision spraying relies on the response of the spraying equipment to the features of the targeted canopy. PWM technology manages the flow rate using a set of electronically actuated solenoid valves to regulate flow rate at the nozzle level. Previous studies have found that PWM systems may deliver incorrect flow rates. The objective of the present study was to characterize the performance of a commercial blast sprayer modified with pulse-width-modulated nozzles under laboratory conditions, as a preliminary step before its further field validation. Four different duty cycles (25 percent, 50 percent, 75 percent and 100 percent) and four different pressures (400 kPa, 500 kPa, 600 kPa and 700 kPa) were combined to experimentally measure the flow rate of each nozzle. Results showed that the PWM nozzles mounted in the commercial blast sprayer, under static conditions, were capable of modulating flow rate according to the duty cycle. However, the reduction of flow rates for the tested duty cycles according to pressure was lower than the percentage expected. A good linear relation was found between the pressure registered by the control system feedback sensor and the pressure measured by a reference conventional manometer located after the pump. High-speed video recordings confirmed the accurate opening and closing of the nozzles according to the duty cycle; however, substantial pressure variations were found at nozzle level. Further research to establish the general suitability of PWM systems for regulating nozzle flow rates in blast sprayers without modifying the system pressure still remains to be addressed.

Proposal for Flood Risk Mitigation in the Upper Tanaro Valley (Western Alps—North-Western Italy)

Flood risk in Italy is a key aspect for the administrative authorities, from the national to the local level. This is especially true in Northern Italy, where the Po River, the most important river of the peninsula, and its river basin are located. In North-Western Italy, the Po Basin is described by numerous sub-basins, among which is the Tanaro River basin: here, in the last decades, floods have produced significant damage, causing an increased concern to local and regional administrations. The main goal of this study was to identify suitable sites for the construction of dams, having the function of retention basins, aiming to mitigate the flood risk in the Upper Tanaro Valley. First, using a qualitative approach, suitable sites were identified using available public data provided by regional administrations and field data obtained from geomorphological surveys, later elaborated in a Geographic Information System (GIS) environment. Several models were then produced using conventional methods to evaluate the hydrological characteristics of the study area and to assess the efficiency of each site in terms of flood water flow rate reduction: the performance was evaluated at control sections chosen in urban areas along the Upper Tanaro Valley. The results show that it is possible to find suitable locations for risk mitigation structures. These models also allowed for a rapid cost-effectiveness evaluation, which led to the definition of the best-performing site. The Upper Tanaro Valley case study here analyzed contributes to proving the importance of an integrated approach based on geomorphological, geo-hydrological, and hydraulic evaluations when dealing with the choice of a flood risk mitigation strategy.

Investigation of Corrosion and Scaling Potential in Drinking Water in Rafsanjan, Iran

Introduction: Corrosion and scaling are important factors affecting drinking water quality, causing health and economic problems. This study aimed to investigate the indicators of corrosion and scaling in Rafsanjan drinking water.&#x0D; Materials and Methods: The present descriptive cross-sectional study was conducted in winter 2018 and spring 2019 in Rafsanjan. The 56 samples were randomly taken from the drinking water distribution and transmission networks. Physicochemical parameters, such as pH, temperature, total dissolved solids (TDS), total hardness (TH), calcium hardness (CH), electrical conductivity (EC), and alkalinity were measured. Finally, corrosion and scaling indices, including langelier index (LI), ryznar index (RI), aggressiveness index (AI), and Puckorius index (PI) were calculated and analyzed.&#x0D; Results: The mean temperature, pH, CH, TH, TDS, alkalinity, and EC were 17.79 ± 0.80 °C, 8.08 ± 0.11, 56.34 ± 2.72 mg/L.CaCO3, 140.86 ± 6.81 mg/L.CaCO3, 530 ± 110 mg/L, 181.21 ± 13.65 mg/L, and 840 ± 180 µs/cm, respectively. The mean corrosion and scaling indices, including LI = 0.18 ± 0.12, RI = 7.72 ± 0.14, AI = 12.09 ± 0.11, and finally PI = 7.96 ± 0.10 were obtained.&#x0D; Conclusion: Based on the obtained data, drinking water in the transmission and distribution network of Rafsanjan has scaling properties. Water scaling and deposition causes problems, such as blockage of water transmission and distribution pipes, reduction of flow rate and increase of pressure drop in the network, and finally increase of water facilities operation costs. Therefore, measures should be considered to control the scaling of water in this region.

Numerical investigation of plasma actuator induced forcing direction on the performance of a low-speed isolated axial compressor rotor

This paper investigates the effects of changing the dielectric barrier discharge (DBD) plasma actuator forcing direction on stall margin improvement and aerodynamic performance of a low-speed axial compressor rotor. The effects of plasma actuator induced force at yaw angles of 0, +30, −30° relative to the rotational axis of the compressor were evaluated through the incorporation of body force spatial distribution into Navier-Stokes equation. The evaluations focused on compressor performance comprising rotor efficiency, total pressure rise coefficient, span-wise loss coefficient, and diffusion factor on one hand and the tip leakage flow structure on the other hand in each configuration. The results indicated that reduction of mass flow rate could be associated with rotor tip spillage and trailing edge backflow, leading to the occurrence of the stall phenomena and flow blockage in the rotor tip region. However, using plasma actuators led to the energized tip region flow structure and improved aerodynamic performance by reducing the size of the tip leakage vortex and flow blockage. Specifically, among proposed configurations, the forcing direction at a yaw angle of −30° improved the compressor stall margin by about 8%. This is mainly due to the higher plasma jet velocity in the relative frame of reference versus to other configurations resulting in higher injected momentum to the tip leakage flow. The results propose counter-flow induced forcing direction as a favorable configuration for stall margin improvement.

Hydrological and water quality simulation and future runoff prediction under CMIP6 scenario in the upstream basin of Miyun Reservoir

AbstractWater resources are a key factor restricting human survival and social and economic development. The Miyun Reservoir, which is the only surface drinking water source in Beijing and the water storage reservoir of the South-to-North Water Diversion Project, plays a decisive role in ensuring water-use sustainability of the capital. This study focused on the Baihe River Basin, which is one of the important inflows of the Miyun Reservoir. The mathematical data on the climate and hydrological changes of the Baihe River Basin over the past 30 years were obtained, and the evolution law of the Baihe River runoff and its influencing factors was analyzed. Our analysis used the data obtained via multi-source meteorology to establish the Soil and Water Assessment Tool (SWAT) model of the Baihe River Basin. Sequential Uncertainty Fitting version 2 (SUFI-2) and Generalized Likelihood Uncertainty Estimation (GLUE) were used to simulate runoff from 1990 to 2017 on a monthly scale, along with sediment, total nitrogen (TN), and total phosphorus (TP) contents from 1990 to 2010. Then, the parameter uncertainty of the SWAT model and the applicability of the SWAT model in the Baihe River Basin were determined. The land-use transfer matrix showed that land-use changes are complex and the transformation forms are diverse. The simulation results showed that the transformation of land-use patterns in 1990 and 2010 had slight impacts on the hydrologic and water quality of the basin. By identifying the key source areas of non-point source pollution in the basin, the impacts of three management measures on the hydrological and water quality of the basin were simulated. The results showed that the reductions in flow rates, sediment content, TN, and TP (4.37, 31.93, 23.13, and 35.30%, respectively) obtained through terrace engineering were significantly better than those acquired via stubble mulch and contour planting. Additionally, this study uses the Sixth International Coupling Mode Comparison Program (CMIP6) climate change scenario and the BCC-CSM2-MR climate model coupled with the corrected SWAT model to predict future runoff, thereby providing references and suggestions for managing the Baihe River Basin and the Miyun Reservoir.