Direction Of Water Flow Research Articles

An integrated multivariate statistical analysis and hydrogeochemical approaches to identify the major factors governing the chemistry of water resources in a mountain region of northwest Italy

The aims of the present investigation are to evaluate the chemical controlling factors of the water resources and identify the source, as well as assess its quality with respect to domestic and irrigation criteria, to establish long-term environmental measures and a sustainable water resources management plan in the mountain regions. For these purposes, 28 water resources (14 drainage; 3 piezometric; 7 Arminaz Stream; 2 spring and 2 Dora River) samples were collected from different locations of the Mont de la Saxe region and analyzed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, and major cations and anions. The pH of the water samples ranged from 7.6 to 11.6, indicating the alkaline nature of the water in the study area. The TDS ranged from 142.1 to 995.3 mg L−1 and exceeded the desirable limit of 500 mg L−1 at some sites. Ca–Mg–HCO3 and Ca–Mg–SO4 were the dominant hydrogeochemical facies; Ca2+ and Mg2+ were the dominant cations and HCO3− and SO42− were the dominant anions in the Mont de la Saxe region. High concentrations of SO42− were attributed to the dissolution of gypsum in the study area. The hydrogeochemical data show the mixing process from the springs pass through higher altitudes drains samples to lower drains samples as well as piezometer. The chemistry of water resources of the study area is mainly controlled by the rock-weathering phenomenon and ion exchange processes as well as by water flow direction of the area. High concentrations of TDS, Ca2+, SO42−, and TH and high salinity in many samples of the drainage and Arminaz Stream water make it unsuitable for domestic and irrigation uses in the study area. This study could be useful for future water resources management in the mountain regions.

The Effect of Feeding Frequency on the Fin Condition in Rainbow Trout (Oncorhynchus mykiss)

Fin condition was assessed in the rainbow trout (Oncorhynchus mykiss) at an experimental recirculating facility using manual feeding 2 and 3 meals per day. Fin Index (FI) was used as an indicator of the find condition. Comparing the feeding frequencies 2 and 3 meals per day, a statistically significant difference was found (p < 0.05) for the FI of the pectoral, pelvic, anal, and caudal fins. For the 3 meals per day feeding frequency, a greater decrease of the FI was found compared to the feeding frequency 2 meals per day. In both pelvic fins the FI decreased by 53 %, in the caudal fins the FI decreased by 18 % and by 11 % in the anal fins, in the left pectoral fin the FI decreased by 6 % and by 12 % in the right one. Statistically significant difference was found between both pectoral fins for the feeding frequency of 3 meals per day. The left pectoral fin showed a FI higher by 8 % compared to the right one; the reason for the asymmetry being the water flow direction in the circular tanks. It follows from the results that in terms of fish welfare, it is more advisable to administer the feed 2 meals per day at maximum, in order to lower the risk of random biting by other individuals and to obtain a better fin condition.

Estimation of Water Level Changes of Large-Scale Amazon Wetlands Using ALOS2 ScanSAR Differential Interferometry

Differential synthetic aperture radar (SAR) interferometry (DInSAR) has been successfully used to estimate water level changes (∂h/∂t) over wetlands and floodplains. Specifically, amongst ALOS PALSAR datasets, the fine-beam stripmap mode has been mostly implemented to estimate ∂h/∂t due to its availability of multitemporal images. However, the fine-beam observation mode provides limited swath coverage to study large floodplains and wetlands, such as the Amazon floodplains. Therefore, for the first time, this paper demonstrates that ALOS2 ScanSAR data can be used to estimate the large-scale ∂h/∂t in Amazon floodplains. The basic procedures and challenges of DInSAR processing with ALOS2 ScanSAR data are addressed and final ∂h/∂t maps are generated based on the Satellite with ARgos and ALtiKa (SARAL) altimetry’s reference data. This study reveals that the local ∂h/∂t patterns of Amazon floodplains are spatially complex with highly interconnected floodplain channels, but the large-scale (with 350 km swath) ∂h/∂t patterns are simply characterized by river water flow directions.

Rivers shape population genetic structure in Mauritia flexuosa (Arecaceae).

The Mauritia flexuosa L.f. palm is known as the “tree of life” given its importance as fundamental food and construction resources for humans. The species is broadly distributed in wet habitats of Amazonia and dry habitats of the Amazon and Orinoco river basins and in the Cerrado savanna. We collected 179 individuals from eight different localities throughout these habitats and used microsatellites to characterize their population structure and patterns of gene flow. Overall, we found high genetic variation, except in one savanna locality. Gene flow between populations is largely congruent with river basins and the direction of water flow within and among them, suggesting their importance for seed dispersal. Further, rivers have had a higher frequency of human settlements than forested sites, contributing to population diversity and structure through increased human use and consumption of M. flexuosa along rivers. Gene flow patterns revealed that migrants are sourced primarily from within the same river basin, such as those from Madeira and Tapajós basins. Our work suggests that rivers and their inhabitants are a critical element of the landscape in Amazonia and have impacted the dispersal and subsequent distribution of tropical palm species, as shown by the patterns of genetic variation in M. flexuosa.

Quality Evaluation of Groundwater Resources using Geostatistical Methods (Case Study: Central Lorestan Plain, Iran)

In this research, based on the qualitative data of 40 wells, variations of water quality parameters of the Central Plain Aquifer were evaluated using kriging and IDW (Inverse Distance Weighting) methods. Owing to the normal distribution of the studied parameters (except Na+, SO42−, and TH: total hardness), ordinary kriging was used for modeling. The analysis of the data trends indicated that all the variables were influenced by in two general trends, i.e., NW–SE and NE–SW. In fact, these trends were a result of the effect of the structural conditions on aquifer properties such as transmissivity and flow direction. Variogram analysis (based on C0 near zero and C0/σ2 ratio between 0.0–0.5) showed that the Na+, TDS (total dissolved solids), Ca2+, and TH variables have a good spatial structure and the BOD (biochemical oxygen demand), COD (chemical oxygen demand), NO3−, and EC variables have poor spatial structure. The BOD, COD, NO3−, and EC (electrical conductivity) variables have the smallest range and isotropic distribution. On the other hand, the Ca2+, Mg2+, Na+, SO42−, Cl−, HCO3−, pH, TDS, TH and Alk (alkalinity) parameters are characterized by anisotropic distributions. The Na+, TDS, Ca2+, and TH variables have the largest range. The results showed that both the IDW and kriging methods have close estimates to one another. The pH variable decreases toward the outlet whereas the EC and TDS variables increase along the direction of water flow and toward the outlet. The distributions of the BOD and COD variables do not perfectly match with the aggregation of industrial activities in the central part as well as the agricultural activities in the southeastern and central parts of the aquifer. The distributions of the Ca2+, Mg2+, and Alk variables completely follow the geology condition and regional spread of carbonate formations. The Na+ concentration increases from the center toward the outlet. The concentration of the Cl− variable is the highest in the central part of the plain due to the concentration of agricultural and industrial activities. The distribution of the SO42− variable is influenced by a natural factor (lithology), especially in the southeastern parts and the outlet as well as artificial factors (agricultural and industrial activities) in the central and southeastern parts of the aquifer. The NO3− variable, which is directly influenced by agricultural and livestock-farming activities, has its maximum concentration in the southeastern areas.

Application of Ground Penetrating Radar Supported by Mineralogical-Geochemical Methods for Mapping Unroofed Cave Sediments

Ground penetrating radar (GPR) using a special unshielded 50 MHz Rough Terrain Antenna (RTA) in combination with a shielded 250 MHz antenna was used to study the capability of this geophysical method for detecting cave sediments. Allochthonous cave sediments found in the study area of Lanski vrh (W Slovenia) are now exposed on the karst surface in the so-called “unroofed caves” due to a general lowering of the surface (denudation of carbonate rocks) and can provide valuable evidence of the karst development. In the first phase, GPR profiles were measured at three test locations, where cave sediments are clearly evident on the surface and appear with flowstone. It turned out that cave sediments are clearly visible on GPR radargrams as areas of strong signal attenuation. Based on this finding, GPR profiling was used in several other places where direct indicators of unroofed caves or other indicators for speleogenesis are not present due to strong surface reshaping. The influence of various field conditions, especially water content, on GPR measurements was also analysed by comparing radargrams measured in various field conditions. Further mineralogical-geochemical analyses were conducted to better understand the factors that influence the attenuation in the area of cave sediments. Samples of cave sediments and soils on carbonate rocks (rendzina) were taken for X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses to compare the mineral and geochemical compositions of both sediments. Results show that cave sediments contain higher amounts of clay minerals and iron/aluminium oxides/hydroxides which, in addition to the thickness of cave sediments, can play an important role in the depth of penetration. Differences in the mineral composition also lead to water retention in cave sediments even through dry periods which additionally contribute to increased attenuation with respect to surrounding soils. The GPR method has proven to be reliable for locating areas of cave sediments at the surface and to determine their spatial extent, which is very important in delineating the geometry of unroofed cave systems. GPR thus proved to be a very valuable method in supporting geological and geomorphological mapping for a more comprehensive recognition of unroofed cave systems. These are important for understanding karstification and speleogenetic processes that influenced the formation of former underground caves and can help us reconstruct the direction of former underground water flows.

Directional selectivity of afferent neurons in zebrafish neuromasts is regulated by Emx2 in presynaptic hair cells.

The orientation of hair bundles on top of sensory hair cells (HCs) in neuromasts of the lateral line system allows fish to detect direction of water flow. Each neuromast shows hair bundles arranged in two opposing directions and each afferent neuron innervates only HCs of the same orientation. Previously, we showed that this opposition is established by expression of Emx2 in half of the HCs, where it mediates hair bundle reversal (<xref ref-type="bibr" rid="bib15">Jiang et al., 2017</xref>). Here, we show that Emx2 also regulates neuronal selection: afferent neurons innervate either Emx2-positive or negative HCs. In emx2 knockout and gain-of-function neuromasts, all HCs are unidirectional and the innervation patterns and physiological responses of the afferent neurons are dependent on the presence or absence of Emx2. Our results indicate that Emx2 mediates the directional selectivity of neuromasts by two distinct processes: regulating hair bundle orientation in HCs and selecting afferent neuronal targets.

Numerical analysis of shell-side flow-induced vibration of elastic tube bundle in heat exchanger

The responses of the flow-induced vibration of an elastic tube bundle subjected to the shell-side cross flow are investigated in this paper. The weak coupling method and the fluid solid interface are used to solve the fluid-structure interaction problem with consideration of the geometry and physical natures. The effects of the shell-side fluid flow velocity and the structural parameters on the flow-induced vibration are discussed. Numerical results demonstrate that the vibration frequency and amplitude at the monitor points increase with the increase of the shell-side water inlet velocity in all directions. The wall thickness and the external diameter of the elastic tube bundle have significant effects on the responses of the flow-induced vibration. The structural parameters affect the vibration frequency and amplitude, and the vibration equilibrium position in the water flow direction. The vibration frequency decreases with the increase of the tube external diameter. In addition, the vibration in the water flow direction has a lower equilibrium position when the elastic tube bundle has a larger wall thickness or smaller external diameter.

Eye wash water flow direction study: an evaluation of the effectiveness of eye wash devices with opposite directional water flow.

IntroductionNew designs of eye wash stations have been developed in which the direction of water flow from the fountain has been reversed, with two water streams originating nasally in both eyes and flowing toward the temporal side of each eye. No study has been done to determine the ideal direction of water flow coming from the eye wash in relation to the eye.Materials and methodsOphthalmic eye examinations were conducted before and after the use of two eye wash stations with opposite water flow directionality. Fluorescein was instilled in both eyes before using an eye wash to measure the effectiveness of the water flow. Subjects were surveyed upon their experiences using the eye washes.ConclusionOphthalmic examination found no significant difference in the efficacy of the eye washes with nasal-to-temporal water flow when compared to temporal-to-nasal water flow direction.

In rough waters, sea bass should stick together

Schooling behaviour in fishes reduces the energetic costs of swimming for the school's members by essentially allowing each fish to ‘draft’ off of others in the group. This phenomenon has been thoroughly studied in laboratory settings under conditions of laminar flow – that is, steady, unidirectional flow with minimal turbulence. However, in the natural environment, water flow can often be turbulent owing to weather, underwater structures, water current dynamics and other factors, which could make it difficult for fish in schools to maintain optimal positions relative to their fellow group members (and thus to reap energetic rewards). Lewis Halsey, of the University of Roehampton in the UK, along with colleagues from the Centre for the Environment and the University of Glasgow, wanted to determine whether schooling behaviour remains energetically advantageous in turbulent conditions. The group further wanted to test whether the size of a school is important in conferring energy cost savings.To address these questions, the researchers placed European sea bass in a special swim flume individually or in groups of three or six fish. Three propellers at one end of the flume allowed the scientists to subject each fish or group of fish to three different water flow rates (20 min at each rate) which, because of the flume design, corresponded to three different levels of turbulence. Using video footage of each trial, the team recorded the three-dimensional position of each fish within the flume, analysed how much (or little) it maintained its position, and determined its tail beat frequency at each flow rate and level of turbulence. After the experiments, to more precisely quantify the turbulence experienced by each fish, the team used a velocimeter to measure the rate and direction of water flow at many different locations within the flume under the three experimental conditions.Halsey and his colleagues found that mean flow rate did not affect tail beat frequency in fish swimming alone or in groups of three. In groups of six fish, tail beat frequency decreased with increasing flow rates, which could reflect more effective drafting among fish in larger schools. Increases in turbulence increased the tail beat frequency in all group sizes, suggesting that swimming generally becomes costlier as flow becomes more uneven. However, fish in larger groups had lower tail beat frequencies in turbulent conditions than fish swimming alone or in smaller groups, indicating that schooling did help conserve energy as it does under laminar flow conditions. Notably, though, the energy cost savings afforded by schooling behaviour in turbulent flow were much lower than those estimated in past studies with laminar flow.Overall, the researchers found that swimming in schools is energetically advantageous for sea bass in dynamic water conditions. However, the metabolic advantage of schooling appears to be smaller in turbulent conditions than in ideal conditions. In addition, the size of a school affects the degree to which changes in water flow rates and patterns influence the energy expenditure of fish within a school. Although more research is needed to better understand the energetic costs and benefits of group swimming in nature, this study shows that when the going gets rough, sea bass should probably stay in school.

A back-analysis method using an intelligent multi-objective optimization for predicting slope deformation induced by excavation

A multi-objective inverse analysis method for slope excavation was proposed, in which orthogonal design, numerical simulation, back propagation neural network (BPNN) and elitist non-dominated sorting genetic algorithm (NSGA-II) were integrated. The multi-objective model is constructed by minimizing a set of multi-objective error functions between the time series of observations and corresponding calculated values. Compared with the back-analysis methods that uses traditional algorithms, the proposed method is validated by a numerical example to be more effective for multi-objective optimization. The methodology is also applied to the excavation of a right bank slope at the Dagangshan hydropower station located in the Sichuan Province, China. The obtained inversion parameters are used in forward analysis to predict displacements. In this case application, three types of field observations are used simultaneously in the back-analysis, which include displacements in the Dadu River water flow (y-) direction, transverse (x-) direction and vertical (z-) direction. Compared with the field displacement data, the trend of the predicted displacements agrees well with the measurements. The results indicate that the proposed method can more precisely and reliably predict the slope deformation induced by excavation.

The effects of vegetation distribution pattern on overland flow

AbstractSoil erosion is a major environmental problem. Vegetation, on the other hand, plays an important role in controlling soil erosion. The goal of the study is to examine the effects of the distribution pattern of vegetation on water flow. The vegetation parameters involved included the direction of plant rows, plant stem diameter and row spacing. To study how vegetation affects the flow of water on slopes, flume simulation experiments were conducted using three different plant row directions, three different plant diameters and three row spacing. Experimental slope is fixed, slope ratio of 1.0%. The hydraulic characteristics of the slope under the three vegetation distribution patterns are explored. The results showed that the pattern of vegetation distribution significantly affected the resistance of vegetation to water flow and pattern on this slope. When the angle (θ) between plant row and water flow directions decreased, the plant diameter (d) increased, or the row spacing (a × a) decreased, the Darcy–Weisbach resistance coefficient (f) for water flow became larger. Simultaneously, the Reynolds and Froude numbers (Re and Fr) both became smaller. In experimental procedure condition, the change rate of f, Re and Fr were analysed by linear regression, the θ decreased every 10°, the average increase rate of f was 6.6%, the average decrease rate of Re and Fr were 2.0 and 3.0%. The d increased every 0.001 m, the average increase rate of f was 41.6%, the average decrease rate of Re and Fr were 11.2 and 12.2%. The a × a decreased every 0.01 m, the average increase rate of f was 45.2%, the average decrease rate of Re and Fr were 11.7 and 10.7%. The flow depth h increased every 0.01 m, the average increase rate of f and Re were 13.6 and 25.2%, and the average decrease rate of Fr was 10.4%. The experimental procedure results will be valuable for not only revealing the hydraulic characteristics of flow over vegetation land, but also the optimisation of the distribution of vegetation on a slope.

Numerical investigation on heat extraction performance of a downhole heat exchanger geothermal system

The downhole heat exchanger (DHE) geothermal system is commonly used to exploit geothermal energy for space heating. In this paper, a 3D unsteady state numerical model is established to couple fluid flow and heat transfer processes of DHE system. The model is validated by field experimental data. Temperature and velocity fields are analyzed to understand thermal process of DHE system. Heat extraction performances of three different DHE structures, including single U-tube, double U-tube and spiral tube, are compared. Subsequently, cases are studied to investigate how key parameters affect DHE performance. Simulation results depict that spiral-tube has the best heat extraction performance. As working fluid mass flow rate rises, outlet temperature declines and thermal power increases. When inlet temperature ascends, outlet temperature rises while thermal power decreases. Effects of reservoir porosity and tube wall heat conductivity on DHE performance are minor. Higher subsurface water velocity and larger rock heat conductivity can improve DHE performance, but the former has a more significant influence. Besides, subsurface water flow direction has neglected influence on performances of single and double U-tube, but appreciable impact on that of spiral tube. Key findings of this work are beneficial for optimal design and optimization of DHE geothermal system.

Numerical simulation and prediction of groundwater environmental contamination in a coastal polyurethane plant based on GMS

GMS was used to simulate the groundwater pollution status during the operation period of a coastal polyurethane factory. Based on the geological and hydraulic data, the groundwater flow field model and solute transport model were established using the MODFLOW and MT3DMS module respectively by which the potential area and concentration of pollutant were predicted and the extent of groundwater pollution in the study area was evaluated. The simulation and prediction results showed that under abnormal conditions, the groundwater environment would be affected. As the characteristic pollutants, COD and ethylene glycol mainly migrated along the direction of water flow and exceeded the standard for a certain period of time. The migration distance and pollution range of contaminants expanded with time, and the peak concentration decreased with the increase of diffusion distance. After 50 years, the potential pollution area of COD and ethylene glycol would reach 225651.2m2 and 210947.5m2 respectively. During the migration process, the concentration of pollutants in the groundwater gradually recovered to the background value, and the over-standard area was reduced to zero. The comprehensive prediction model and risk assessment method of this study can help to formulate practical prevention and control measures for the protection of groundwater environment.

Understanding the Burial and Migration Characteristics of Deep Geothermal Water Using Hydrogen, Oxygen, and Inorganic Carbon Isotopes

Geothermal water samples taken from deep aquifers within the city of Kaifeng at depths between 800 and 1650 m were analyzed for conventional water chemical compositions and stable isotopes. These results were then combined with the deuterium excess parameter (d value), and the contribution ratios of different carbon sources were calculated along with distributional characteristics and data on the migration and transformation of geothermal water. These results included the conventional water chemical group, hydrogen, and oxygen isotopes (δD-δ18O), dissolved inorganic carbon (DIC) and associated isotopes (δ13CDIC). The results of this study show that geothermal water in the city of Kaifeng is weakly alkaline, water chemistry mostly comprises a HCO3-Na type, and the range of variation of δD is between −76.12‰ and −70.48‰, (average: −74.25‰), while the range of variation of δ18O is between −11.08‰ and −9.41‰ (average: −10.15‰). Data show that values of d vary between 1.3‰ and 13.3‰ (average: 6.91‰), while DIC content is between 91.523 and 156.969 mg/L (average: 127.158 mg/L). The recorded range of δ13CDIC was between −10.160‰ and −6.386‰ (average: −9.019‰). The results presented in this study show that as depth increases, so do δD and δ18O, while d values decrease and DIC content and δ13CDIC gradually increase. Thus, δD, δ18O, d values, DIC, and δ13CDIC can all be used as proxies for the burial characteristics of geothermal water. Because data show that the changes in d values and DIC content are larger along the direction of geothermal water flow, so these proxies can be used to indicate migration. This study also shows demonstrates that the main source of DIC in geothermal water is CO2thathas a biological origin in soils, as well as the dissolution of carbonate minerals in surrounding rocks. Thus, as depth increases, the contribution of soil biogenic carbon sources to DIC decreases while the influence of carbonate dissolution on DIC increases.

The use of vertical flow constructed wetlands for the treatment of hyper-eutrophic water bodies with dense cyanobacterial blooms.

Eutrophication often leads to the periodic proliferation of harmful cyanobacterial blooms (HCBs), which threaten the sustainability of freshwater ecosystems and lead to serious environmental, health and economic damage. Hence, it is vitally important to take effective measures to manage HCBs and associated problems. In this study, vertical flow constructed wetlands (CWs) were operated under different hydraulic loading rates (HLRs) to treat a hyper-eutrophic water body with HCBs. Six sampling ports (representing different layers) were evenly distributed along the water flow direction to study the purification processes of CWs. With HLRs ranging from 0.2 m/d to 0.8 m/d, total nitrogen (TN), total phosphorus (TP), COD, total suspended solid (TSS) and Chlorophyll a (Chl.a) were efficiently treated by CWs, and they were mainly removed at the second layer of CWs. The concentrations of two cyanobacterial metabolites (geosmin and β-cyclocitral) in the effluent were mostly below their odorous threshold concentrations. As the HLRs increased, the treatment efficiencies of the CWs decreased gradually. There was no removal of TP, Chl.a, geosmin, or β-cyclocitral at an HLR of 1.0 m/d. Under suitable HLRs, this type of CW could provide a promising way to control HCBs and associated odorous problems in hyper-eutrophic water bodies.

Influence of direct and alternating current electric fields on efficiency promotion and leaching risk alleviation of chelator assisted phytoremediation

Direct and alternating current electric fields with various voltages were used to improve the decontamination efficiency of chelator assisted phytoremediation for multi-metal polluted soil. The alleviation effect of electric field on leaching risk caused by chelator application during phytoremediation process was also evaluated. Biomass yield, pollutant uptake and metal leaching retardation under alternating current (AC) and direct current (DC) electric fields were compared. The biomass yield of Eucalyptus globulus under AC fields with various voltages (2, 4 and 10 V) were 3.91, 4.16 and 3.67kg, respectively, significantly higher than the chelator treatment without electric field (2.71kg). Besides growth stimulation, AC fields increased the metal concentrations of plant tissues especially in aerial parts manifested by the raised translocation factor of different metals. Direct current electric fields with low and moderate voltages increased the biomass production of the species to 3.45 and 3.12kg, respectively, while high voltage on the contrary suppressed the growth of the plants (2.66kg). Under DC fields, metal concentrations elevated obviously with increasing voltages and the metal translocation factors were similar under all voltages. Metal extraction per plant achieved the maximum value under moderate voltage due to the greatest biomass production. DC field with high voltage (10V) decreased the volume of leachate from the chelator treatment without electric field from 1224 to 56mL, while the leachate gathered from AC field treatments raised from 512 to 670mL. DC field can retard the downward movement of metals caused by chelator application more effectively relative to AC field due to the constant water flow and electroosmosis direction. Alternating current field had more promotive effect on chelator assisted phytoremediation efficiency than DC field illustrated by more metal accumulation in the species. However, with the consideration of leaching risk, DC field with moderate voltage was the optimal supplementary technique for phytoremediation.

DESIGN AND OPTIMIZATION OF PERMANENT MAGNET SYNCHRONOUS GENERATOR FOR USE IN HYDRODYNAMIC RENEWABLE ENERGY BY APPLYING ACO AND FEA

One of the most important ways to reduce fossil fuel consumption and consequently reduce greenhouse gases and environmental pollution is the use of renewable energies such as water, sun, wind, etc. One of the most efficient ways to take advantages of the shallow flowing waters such as rivers and fountains in electrical power generation is the use of hydrodynamic screw in the direction of water flow. The design of the generator for this application results in environmental dangers decrease. On the other hand, it provides some part of electrical energy required for human beings. Generators in hydrodynamic renewable energy system ought to have features such as high efficiency, power density and reliability as well as low volume. Among various generators, the permanent magnet synchronous generator (PMSG) meets these requirements very well. In this paper, first, analytical calculations and the design process of PMSG were explained. Then, the ant colony optimization (ACO) was used for the optimization of design quantities. PMSG design optimization increased in efficiency and decreased in volume. By improving these two parameters in the designed PMSG, it gets very suitable to be used in hydrodynamic renewable energy system. Finally, the results of the optimized design of PMSG were validated through simulation of it in Maxwell software and applying finite element analysis (FEA). Also the final results have been compared to similar experimental researches results.

Geophysical methods integration for deep aquifer reservoir characterization and modeling (Sidi Bouzid basin, central Tunisia)

Groundwater resources of the Sidi Bouzid basin (central Tunisia) are hydrogeologically and economically important. This importance is restrained by the complex and poorly understood subsurface geometry of the main basin, the overexploitation of its near-surface aquifers and the lack of deep hydrogeological wells in the study area. To overcome these issues a multidisciplinary study was conducted integrating geological, geophysical, and hydrogeological methods. As the regional structural tendency of the study area is predominated by Atlassic NE-SW trends, gravity anomalies could be defectively interpreted. Thus, different gravity treatments and filters were processed. A residual gravity response of Sidi Bouzid basin was rationally isolated, the main structural features were then outlined and depths of rooted sources were detected. The obtained results are in a good conformity revealing a newly detected sub-horizontal geophysical lineament that seems to be a high zone which may act as a hydrogeological barrier within the investigated basin.Forward gravity modeling supported by 2D seismic reflection data over geological and geophysical methods integration, highlighted the Sidi Bouzid basin subsurface extent. It also defined its thick Tertiary complex substratum and the unknown total thickness and arrangement of its subsurface series. The used approaches provided a depth to basement modeling of the siliciclastic Tertiary complex estimating its depth and disclosing its subsurface configuration and its internal preferential water flow directions. A geophysical basement topography mapping enhancing the subsurface overview was also yielded.

Characteristics of GHG flux from water-air interface along a reclaimed water intake area of the Chaobai River in Shunyi, Beijing

To understand greenhouse gas (GHG) flux in reclaimed water intake area impact on urban climate, ‘static chamber’ method was used to investigate the spatio-diurnal variations and the influence factors of GHG fluxes at water-air interface from Jian River to Chaobai River. Results showed that the average fluxes of CO2 from the Jian River and the Chaobai River were 73.46 mg(m2·h)−1 and -64.75 mg(m2·h)−1, respectively. CO2 was emitted the most in the Jian River, but it was absorbed from the atmosphere in the Chaobai River. Unary linear regression analyses demonstrated that Chlorophyll a (Chl a) and pH variation controlled the carbon source and sink from the Jian River to the Chaobai River. The diurnal variation of CO2 fluxes was higher at night than in the daytime in the Jian River, and it was the inverse in the Chaobai River, which highly correlated with dissociative CO2 and HCO3− transformation to CO32-. The average fluxes of CH4 from the Jian River and Chaobai River were 0.973 mg(m2·h)−1 and 5.556 mg(m2·h)−1, respectively, which increased along the water flow direction. Unary and multiple linear regression analyses demonstrated that Chl a and total organic carbon (TOC) controlled the increase of CH4 along the flow direction. The diurnal variation of CH4 fluxes was slightly higher in the daytime than at night due to the effect of water temperature.