Hasil untuk "Hydraulic engineering"

Yi Liu, Wenzhi Zeng, Chang Ao et al.

Soil salinization impairs fertility and reduces crop productivity across more than 6 % of the world’s arable land. Traditional remediation approaches, like chemical amendments, are often costly and involve ecological compromises. This study investigates an innovative nano-bio strategy that integrates multi-walled carbon nanotubes (MWCNTs) with Bacillus subtilis (B. subtilis) under drip irrigation to boost maize tolerance in saline environments. Germination tests and field studies were conducted in soils treated with 50 mM NaCl. The results from four comparative treatments revealed that MWCNTs markedly improved seed germination (achieving 52 % by day two versus 24 % in controls) and enhanced root elongation by 52.36 %. These effects were linked to the upregulation of key ion transporters (ZmSKOR). Furthermore, MWCNTs application enhanced the expression of aquaporin genes ZmPIP1;1 and ZmPIP2;1. Although B. subtilis alone had a minimal impact on germination, its combination with MWCNTs fostered stronger soil-microbe-nanomaterial interactions under drip irrigation. This synergy increased maize yield by 20.6 %, raised the 1000-grain weight by 3.08 %, lowered the leaf Na⁺/K⁺ ratio by 19.93 %, and improved antioxidant defense mechanisms, such as a 10.44 % rise in SOD activity. Importantly, while MWCNTs alone decreased soil nitrogen in non-saline conditions, adding B. subtilis helped rebalance nutrients, an effect that was reinforced by the uniform distribution provided by drip irrigation. The mechanism involves improved nutrient assimilation, better stomatal control, and reduced reactive oxygen species under salt stress. These findings indicate that the MWCNTs and B. subtilis act synergistically with drip irrigation via molecular soil-root interactions to mitigate salt toxicity. This integrated approach, which combines nanotechnology, microbiome engineering, and water-efficient irrigation, offers a sustainable and effective solution for reclaiming saline soils and advancing stress-resistant agriculture.

Yuhang Liang, Zhaoyong Li, Xiaolin Li et al.

In view of the subjectivity and limitations of scenario setting, as well as the time-consuming nature of computations and difficulty of obtaining global optimal solutions, this paper proposes an ecological water replenishment optimisation model by coupling a hydrodynamic model and an optimisation algorithm. The proposed model aims to obtain the most optimal water replenishment plan to meet specific objectives, by using the hydrodynamic model to obtain relationship curves between various hydrodynamic indicators (e.g. water level, discharge, flow velocity) and different ecological water replenishment flows, and combining these curves with the optimisation algorithm. The model was applied to the Beijing section of the Yongding River. The minimum water replenishment flow at the cross section of Guanting Reservoir is 30 m3/s, to meet the goal of full-channel waterflow connectivity in the Beijing section of Yongding River. A comprehensive optimal ecological water replenishment plan is proposed under the consideration of three objectives in the best state possible, i.e. the maximum guaranteed rate of suitable ecological flow, the highest monthly average ecological water replenishment efficiency and the maximum guaranteed rate of full-channel waterflow connectivity. This study provides novel insights and methodologies for the formulation of ecological water replenishment plans for water-deficient rivers.

LI Zheng, CAO Shu-long, ZHU Hai-qin, XIE Ping, JIA Bao-jie

[Objective] Water-level fluctuation zone (WLFZ) represents a key challenge for managing carbon emissions from global reservoirs. The Three Gorges Reservoir (TGR) has become a key focus for investigating the emission of greenhouse gases, such as carbon dioxide (CO2). Previous studies have not yielded consistent findings regarding the correlation between different elevations and soil carbon release — a gap that limits an accurate understanding of carbon cycling mechanisms in the reservoir’s WLFZ and hinders effective carbon emission management. [Methods] This study explored soil carbon emission characteristics in the near-dam WLFZ of TGR under fluctuating water levels. Soil respiration rates were measured using the Li-8100 Automated Soil CO2 Flux System. Two representative WLFZs—Longtanping and Lanlingxi—were selected, and within each area, three elevation intervals were established: below 160 m, 160-170 m, and above 170 m. This design ensured that the data would reflect the impact of water level fluctuations on soil carbon emissions across different WLFZ segments. One-way analysis of variance (ANOVA) in SPSS 25.0 was applied to examine differences in soil respiration across elevations and seasons. [Results] No positive correlation was found between elevation and soil respiration. Instead, as elevation increased, soil respiration across the entire study area exhibited a trend of first rising and then falling, with the maximum rate observed under moderate flooding stress. Specifically, the peak soil respiration rate reached 3.91 μmol/m2/s in Longtanping and 2.69 μmol/m2/s in Lanlingxi, with an average of 3.30 μmol/m2/s. This suggested that moderate flooding created optimal conditions for soil microbial activity and organic matter decomposition—two processes that drove carbon emission—whereas excessive or insufficient flooding inhibited these biological activities, reducing respiration rates. When the two WLFZs were analyzed comprehensively and Lanlingxi individually, no significant difference in soil respiration was found between the below-160 m and above-170 m intervals. However, in Longtanping, soil respiration above 170 m was slightly higher than that below 160 m. This regional discrepancy might be attributed to differences in local environmental factors, such as soil texture, organic matter content, vegetation coverage, or microbial community composition. Soil respiration exhibited significant temporal variability. Overall, the seasonal trend showed rates in July and August being highest, followed by September, June, and May. Minor differences existed between the two WLFZs: Longtanping showed a pattern where rates in July and August were highest, followed by September and June, and then May, while Lanlingxi displayed a pattern where rates in July, August, and September were equal and higher than June and May. Nevertheless, both areas recorded their peak soil respiration in August, with the highest rates occurring in the 160-170 m interval: 6.97 μmol/m2/s in Longtanping and 4.58 μmol/m2/s in Lanlingxi. The elevated summer respiration rates (especially in July and August) were primarily linked to vigorous vegetation growth and metabolic activity during this period. Vegetation contributed to carbon emission by releasing organic matter through root exudation and litterfall (providing substrates for microbes) and enhancing soil aeration via root respiration (facilitating microbial decomposition). [Conclusion] Moderate dry-wet alternation (i.e., moderate flooding stress) maximizes soil carbon emissions in the study area, while extreme flooding (either too high or too low) suppresses emission intensity. Summer, characterized by robust vegetation growth and metabolism, shows significantly higher soil respiration than other seasons—with July and August showing particularly high rates, and the moderately flooded zones in August recording the peak. The findings of this study have both theoretical and practical value. Theoretically, they enhance the understanding of carbon cycling in large reservoir WLFZ and contribute to global carbon cycle research. Practically, they provide a scientific basis for the quantitative analysis of carbon emissions in the Three Gorges Reservoir’s WLFZs and support future studies on carbon cycling following WLFZ ecological restoration. This information can further guide water level management strategies to regulate soil carbon emissions, aiding global carbon neutrality efforts and the sustainable development of the reservoir ecosystem.

WANG Luoxi, HAN Peifeng, LI Yan'ang et al.

Since the 20th century, earth-rockfill dam instability accidents have occurred frequently all over the world. In order to systematically summarize the current status and hotspots of research on earth-rockfill dam stability and analyze the future development trend of earth-rockfill dam stability, this paper sorted out the factors of earth-rockfill dam instability found by Chinese and foreign scholars and carried out a comparative analysis. Since The instability modes of earth-rockfill dams are complex and varied, the research on the different instability modes of earth-rockfill dams by Chinese and foreign scholars was summarized. In terms of theoretical calculation, the calculation models developed by Chinese and foreign scholars for the instability of earth-rockfill dams were systematically sorted out, and the applicability of different calculation models was compared. In order to quantitatively and visually analyze the research hotspots and trends of Chinese and foreign scholars on the instability of earth-rockfill dam, CiteSpace was used to analyze 1 197 papers on the stability of earth-rockfill dam in CNKI and Web of Science in the past 15 years from 2009 to 2023, and the research dynamics of the field in the past 15 years were comprehensively and visually analyzed according to the author groups, research institutions, and keyword clustering. The development trend of the existing research, as well as the related problems and future research work, were discussed and prospected from a macro perspective. The future research direction of the stability of earth-rockfill dams, as well as the difficulties and hotspots of the current research were summarized.

Hossain Md Anawar, R. Chowdhury

Selection of appropriate river water treatment methods is important for the restoration of river ecosystems. An in-depth review of different river water treatment technologies has been carried out in this study. Among the physical-engineering processes, aeration is an effective, sustainable and popular technique which increases microbial activity and degrades organic pollutants. Other engineering techniques (water diversion, mechanical algae removal, hydraulic structures and dredging) are effective as well, but they are cost intensive and detrimental to river ecosystems. Riverbank filtration is a natural, slow and self-sustainable process which does not pose any adverse effects. Chemical treatments are criticised for their short-term solution, high cost and potential for secondary pollution. Ecological engineering-based techniques are preferable due to their high economic, environmental and ecological benefits, their ease of maintenance and the fact that they are free from secondary pollution. Constructed wetlands, microbial dosing, ecological floating beds and biofilms technologies are the most widely applicable ecological techniques, although some variabilities are observed in their performances. Constructed wetlands perform well under low hydraulic and pollutant loads. Sequential constructed wetland floating bed systems can overcome this limitation. Ecological floating beds are highly recommended for their low cost, high effectiveness and optimum plant growth facilities.

Guanlong Yu, Jiajun Huang, Huifang Chen et al.

Constructed wetlands (CWs) are a kind of green environmental protection technology, which are widely used in sewage treatment. Traditional CWs are faced with the problem of a low treatment effect of high-concentration sewage. In recent years, biochar, as a new type of adsorption material, has been used in CWs because of its advantages of large specific surface area, strong adsorption capacity, and wide material sources. This paper systematically summarized the characteristics of biochar and the preparation of biochar by studying the changes in microorganisms added to CWs and compared the effects of different treatment methods coupled with biochar on the treatment performance of CWs. The effects of biochar coupled with CWs on enzyme activity, functional genes, metabolites, and microbial communities were investigated. This review summarizes how different preparation methods affect the properties of biochar and how these biochar properties cause changes in the microorganisms added to CWs. It provides a new theoretical basis for the treatment of pollutants in CWs.

B. Sadeghi, B. Farhadi Bansouleh, A. Bafkar et al.

IntroductionThe rapid growth of the world's population, followed by an increase in the need for water, has put great pressure on water resources, so it is necessary to plan for the optimal use and increase of efficiency of this vital resource. Sunflower is one of the most important oilseed crops that is mainly cultivated in Kermanshah province. Therefore, determining the appropriate sowing time of this crop for maximum production and water use efficiency is of particular importance. Because field experiments are costly and time-consuming, researchers use crop growth simulation models to determine the optimal planting time for each crop in a specific environment and climate. The use of simulation models minimizes the limitations of field experiments and allows the analysis of plant responses to environmental stresses and management scenarios. The objective of this study was to determine the optimal planting date of the Farrokh sunflower cultivar in four regions of Kermanshah province (Kermanshah, Islam Abad, Sarpol Zahab, and Kangavar) in order to maximize yield and water use efficiency using the AquaCrop model.Materials and MethodsA field experiment was conducted at the Research Farm of Razi University, Kermanshah, Iran in order to calibrate and validate the crop parameters in the AquaCrop model. The experiment was performed in a randomized complete block design with eight irrigation treatments in three replications. The irrigation treatments were the application of 60, 80, 100, and 120% of irrigation requirement (T1, T2, T3, and T4), 20 and 40% deficit irrigation in vegetative phase (T5 and T6), and 20 and 40% deficit irrigation in reproductive phase (T7 and T8). The crop water requirement was calculated based on the daily weather data collected from an automated meteorological station at the Research Farm using the FAO Penman-Monteith equation. During the growing season, canopy cover, biomass, and soil moisture were measured weekly. The crop parameters were calibrated based on the measured data in treatments T1, T3, T6, and T7 and validated with four treatments T2, T4, T6, and T8. In the calibration and validation stages, the statistical indices including compatibility index (d) and root mean square error (RMSE) were used to evaluate the model outputs. The calibrated model was used to simulate crop growth based on daily weather data for 30 years (1988-2017) in four synoptic stations in Kermanshah province (Kermanshah, Islam Abad, Sarpol Zahab, and Kangavar) and for several different planting dates. The crop water productivity was calculated based on simulated grain yield and seasonal crop evapotranspiration. Finally, the model outputs under different planting dates were analyzed to determine the most appropriate planting time from the perspective of maximum production and maximum water use efficiency.Results and Discussion Statistical indicators show that the model has simulated the parameters of biomass, crop canopy, and soil moisture in the calibration stage with good accuracy. T1 and T6 treatments in biomass simulation, T7, T6, and T3 treatments in crop canopy simulation, and T3 and T7 treatments in soil moisture simulation had the highest accuracy. The accuracy of the model outputs in the validation stage for biomass and canopy cover was as accurate as in the calibration stage, while the accuracy of the simulated soil moisture in the validation stage was not high except in T4 treatment. Based on the model results, grain yield, seasonal evapotranspiration and water productivity were determined. According to the results, it can be said that in the study period (1988 -2017), grain yield has generally increased with a slight slope. The results showed that the planting date, which maximizes grain yield and water productivity, varies in the studied regions.  According to the model results, planting in the second decade of May and the second decade of June will lead to the highest grain yield and water productivity in Kermanshah, respectively. Planting in the third decade of May showed the highest grain yield and crop water productivity in Islam Abad. In Sarpol Zahab, which has the highest temperature among the studied stations, planting in the last decade of March and the first decade of April has the highest grain yield and water productivity, respectively. In Kangavar, which is located in the east of Kermanshah province and has the coldest climate, by cultivating sunflower in the last decade of May and the first decade of June, respectively, the highest grain yield and water productivity can be achieved.ConclusionDue to the fact that some crop parameters of crop growth simulation models are variety specific, in this study, the crop parameters of the AquaCrop model for Farrokh sunflower cultivar were calibrated and validated. The accuracy of the calibrated model for estimating biomass and canopy cover was higher than soil moisture. The simulation results showed that the values of the studied parameters (grain yield and seasonal evapotranspiration) have changes according to the planting time in each region. The highest crop yield can be obtained in Sarpol Zahab, Islam Abad, Kermanshah, and Kangavar regions (west to east of the province) by cultivation in the last decade of March, last decade of April, the second decade of May, and last decade of May, respectively. In all study areas except Islamabad, planting date that resulted in maximum water productivity was different from the planting date that had maximum grain yield station and delayed planting had the highest water productivity.

محمد جلینی, محمد کریمی, جواد باغانی

باتوجه ‏به کمبود آب در کشور، بهبود مدیریت آبیاری مزارع سیب‌زمینی می‌تواند کاهش مصرف آب و افزایش بهره‏ وری آب این محصول مهم را به همراه داشته باشد. به این منظور، لازم است اطلاع کافی و دقیقی از وضعیت میزان آب کاربردی و بهره‌وری آب در شرایط مدیریت زارعین وجود داشته باشد. ازاین‏‌رو میزان آب کاربردی، عملکرد و بهره‌وری آب در شرایط مدیریت زارعین در دو منطقه عمده تولید سیب‌زمینی در استان خراسان رضوی بررسی شد. دو منطقه فریمان و تربت حیدریه با بیشترین سطح زیرکشت و تولید محصول سیب ‏زمینی به‏ عنوان شهرستان‏‌های پایلوت انتخاب شدند. روش آبیاری تمام مزارع، روش قطره‏‌ای (تیپ) بود. در مزارع آزمایشی، خصوصیات آبی و زراعی، مشخصات منبع آب و شبکه آبیاری، داده‌های هواشناسی مورد نیاز، حجم آب کاربردی، عملکرد سیب‌زمینی و بهره‌وری آب در سال زراعی 1398 اندازه‌گیری شد. همچنین حجم آب کاربردی توسط کشاورزان با نیازآبیاری برآورد شده براساس داده‌های هواشناسی سال 98 و ده ساله اخیر محاسبه شده به روش پنمن- مانتیث مقایسه شد. مقدار آب کاربردی بر اساس داده‌های هواشناسی سال 98 حدود 26 درصد و نسبت به آمار 10 ساله حدود 15 درصد بیشتر بود. نتایج همچنین نشان داد، حجم آب کاربردی سیب‌زمینی در مزارع مورد مطالعه از 9888 تا 14573 مترمکعب در هکتار متغیر و میانگین آن 11885 مترمکعب در هکتار بود. عملکرد سیب‌زمینی در مزارع منتخب از 28600 تا 60000 کیلوگرم ‌بر هکتار متغیر و میانگین آن 40399 کیلوگرم ‌بر هکتار بود. بهره‌‏وری آب از 2/22 تا 5/25 متغیر و میانگین 3/42 کیلوگرم ‌بر مترمکعب بود.

João Paulo Lyra Fialho Brêda, Rodrigo Cauduro Dias de Paiva, Olavo Corrêa Pedrollo et al.

ABSTRACT Reservoirs considerably affect river streamflow and need to be accurately represented in environmental impact studies. Modeling reservoir outflow represents a challenge to hydrological studies since reservoir operations vary with flood risk, economic and demand aspects. The Brazilian Interconnected Energy System (SIN) is an example of a unique and complex system of coordinated operation composed by more than 160 large reservoirs. We proposed and evaluated an integrated approach to simulate daily outflows from most of the SIN reservoirs (138) using an Artificial Neural Network (ANN) model, distinguishing run-of-the-river and storage reservoirs and testing cases whether outflow and level data were available as input. Also, we investigated the influence of the proposed input features (14) on the simulated outflow, related to reservoir water balance, seasonality, and demand. As a result, we verified that the outputs of the ANN model were mainly influenced by local water balance variables, such as the reservoir inflow of the present day and outflow of the day before. However, other features such as the water level of 4 large reservoirs that represent different regions of the country, which infers about hydropower demand through water availability, seemed to influence to some extent reservoirs outflow estimates. This result indicates advantages in using an integrated approach rather than looking at each reservoir individually. In terms of data availability, it was tested scenarios with (WITH_Qout) and without (NO_Qout and SIM_Qout) observed outflow and water level as input features to the ANN model. The NO_Qout model is trained without outflow and water level while the SIM_Qout model is trained with all input features, but it is fed with simulated outflows and water levels rather than observations. These 3 ANN models were compared with two simple benchmarks: outflow is equal to the outflow of the day before (STEADY) and the outflow is equal to the inflow of the same day (INFLOW). For run-of-the-river reservoirs, an ANN model is not necessary as outflow is virtually equal to inflow. For storage reservoirs, the ANN estimates reached median Nash-Sutcliffe efficiencies (NSE) of 0.91, 0.77 and 0.68 for WITH_, NO_ and SIM_Qout respectively, compared to a median NSE of 0.81 and 0.29 for the STEADY and INFLOW benchmarks respectively. In conclusion, the ANN models presented satisfactory performances: when outflow observations are available, WITH_Qout model outperforms STEADY; otherwise, NO_Qout and SIM_Qout models outperform INFLOW.

Tsukasa Ito, Yu Yamanashi, Naoki Noguchi et al.

The public sewage (PS) and night soil mixed with johkasou sludge (JO) have similar chemical compositions; however, the concentrations of organic matter and nitrogen compounds were different. We investigated the microbial community of the rotating biological contactor (RBC) units treating PS and JO, in which the RBC was submerged in the mixed liquor of activated sludge. Here, we observed that the microbial community compositions at the phylum and class levels were similar between the PS-RBC and JO-RBC, whereas the relative abundances of several phyla (Euryarchaeota, Acidobacteria, Chloroflexi, Firmicutes, Patescibacteria, and Betaproteobacteria) significantly differed between them. The microbial community composition of RBC (an attached growth process) was similar to that of the activated sludge (a suspended growth process). The microbial community of activated sludge likely affected that of RBC. The relative abundance of total denitrifying bacteria in the PS-RBC was twice as much as that in JO-RBC, while nitrifying bacterial phylotypes had a similar relative abundance. The predominant denitrifying genera were different between the PS-RBC and JO-RBC, as well as in the cross-sectional layers of the PS-RBC, suggesting the functional diversity of denitrifying bacterial genera inhabiting the RBC.

GUAN Guanghua, LI Huiying, SU Haiwang et al.

【Background】 Open channels have been widely used to transfer water in many projects. Automatically controlling them is a prerequisite in realizing intelligent management, optimizing water distribution, and achieving flexible water supply in emergency. Traditional automatic control systems normally use water level, flow rate, or storage pool as objective to control the channel operation based on some logic analysis. Existing control operation modes include keeping the upstream and downstream water levels constant, equal-volume method and control-volume method, with the control-volume method being most flexible and able to quickly respond to any changes. The disadvantage of the control-volume method is that it only uses the volume of a single channel section as its control objective. Therefore, its storage capacity is limited, and it cannot complement adjacent channels. 【Objective】 The objective of this paper is to resolve the inferiorities of the control-volume method, including limited storage capacity, inability to adjust the changes in the storage capacity between adjacent channels when using the storage capacity of a single section as the control objective. 【Method】 The proposed method was based on the balanced operation mode of multi-channel pool storage capacity with equal downstream water depth. We established a robust and easy-to-implement model to calculate the gate target flow based on the change in storage capacity, which not only keeps the total storage capacity of the channel unchanged, but also makes the downstream target water depth in each channel pool consistent. As a validation and verification, we applied the model to Jiping main canal on the east route of the south-north water transfer project. 【Result】 In the multi-canal pool storage balance mode, multiplying the storage difference by a weight coefficient can effectively reduce the gate flow overshoot and shorten the time it takes the system to stabilize. Under normal operating conditions, the regulation pressure on the head reservoir in the canal calculated by the proposed method was lower than that calculated by the conventional downstream constant water level control mode. Overall, the proposed method improved all dimensionless performance indexes, with the system stabilization time reduced by up to 10 hours. Considering that the difference in pool lengths in a canal could be more than 10 times, it is found that when there are large flow changes, adding a control gate to reduce the length of a single pool can further reduce the overall stabilization time and improve all dimensionless performance indexes. 【Conclusion】 Multi-channel pool storage control works better than the single channel pool storage control system, and the method we proposed lays a foundation for its further study and improvement.

WANG Libo, CEN Weijun, ZHENG Changhai

In view of the seepage of the dam body and dam foundation of a dangerous masonry gravity dam,this paper puts forward the seepage repair scheme of laying geomembrane on the dam surface and strengthening the curtain of the dam foundation,calculates the seepage field of the dam under multiple working conditions by the finite element method for obtaining the distribution of the equal head line,the height of the seepage line,the seepage gradient and the seepage flow of the dam,and emphatically demonstrates and analyzes the anti-seepage effect of geomembrane and curtain.The results show that:The geomembrane on the upstream face of the dam can significantly reduce the water head,the position of the dam seepage line after laying with the geomembrane is low,and the seepage flow of the dam is small.The curtain after reinforcement of dam foundation also has a good anti-seepage effect,which effectively limits the seepage of dam foundation,and the seepage gradient of curtain is smaller than the allowable gradient.Therefore,it is reasonable and feasible to use geomembrane combined with curtain reinforcement to repair the seepage of masonry gravity dam.

Juncai Xu, Jingkui Zhang, Weigang Sun

Ground-penetrating radar (GPR) signal recognition depends much on manual feature extraction. However, the complexity of radar detection signals leads to conventional intelligent algorithms lacking sufficient flexibility in concrete pavement detection. Focused on these problems, we proposed an adaptive one-dimensional convolution neural network (1D-CNN) algorithm for interpreting GPR data. Firstly, the training dataset and testing dataset were constructed from the detection signals on pavement samples of different types of distress; secondly, the raw signals are were directly inputted into the 1D-CNN model, and the raw signal features of the radar wave are extracted using the adaptive deep learning network; finally, the output used the Soft-Max classifier to provide the classification result of the concrete pavement distress. Through simulation experiments and actual field testing, the results show that the proposed method has high accuracy and excellent generalization performance compared to the conventional method. It also has practical applications.

Guan Hongjie, Liu Xinyu

The presence of biocrusts changes water infiltration in the Mu Us Desert. Knowledge of the hydraulic properties of biocrusts and parameterization of soil hydraulic properties are important to improve simulation of infiltration and soil water dynamics in vegetation-soil-water models. In this study, four treatments, including bare land with sporadic cyanobacterial biocrusts (BL), lichen-dominated biocrusts (LB), early-successional moss biocrusts (EMB), and late-successional moss biocrusts (LMB), were established to evaluate the effects of biocrust development on soil water infiltration in the Mu Us Desert, northwest of China. Moreover, a combined Wooding inverse approach was used for the estimation of soil hydraulic parameters. The results showed that infiltration rate followed the pattern BL > LB > EMB > LMB. Moreover, the LB, EMB, and LMB treatments had significantly lower infiltration rates than the BL treatment. The saturated soil moisture (θs) and shape parameter (αVG) for the EMB and LMB treatments were higher than that for the BL and LB treatments, although the difference among four treatments was insignificant. Water retention increased with biocrust development at high-pressure heads, whereas the opposite was observed at low-pressure heads. The development of biocrusts influences van Genuchten parameters, subsequently affects the water retention curve, and thereby alters available water in the biocrust layer. The findings regarding the parameterization of soil hydraulic properties have important implications for the simulation of eco-hydrological processes in dryland ecosystems.

Algirdas Radzevičius, Midona Dapkienė, Nomeda Sabienė et al.

Our research aim was to apply UV/Vis spectrophotometric techniques for the rapid monitoring of the quality of water sourced from on-farm root vegetable washing processes. To achieve this goal, the quality assessment of the washing water and wastewater at different stages of the technological processes was performed using physicochemical, biological, and UV/Vis absorbance measurements as well as statistical methods, such as principal component analysis (PCA) and partial least squares (PLS) regression. Limit values of UV/Vis absorbance at specific wavelengths were predicted in order to adapt them for routine testing and water quality monitoring at the farm packhouses. Results of the lab analyses showed, that the main problems of the water quality were caused by suspended solids (470–3400 mg L⁻¹), organic substances (BOD₅ 215–2718 mg L⁻¹; COD 540–3229 mg L⁻¹), nitrogen (3–52 mg L⁻¹), phosphorus (1–6 mg L⁻¹), and pathogenic microorganisms (TVC > 300 cfu mL⁻¹, <i>E. coli</i> 5.5 × 10³–1.0 × 10⁴ cfu mL⁻¹, intestinal enterococci 2.8 × 10²–1.5 × 10⁴ cfu mL⁻¹, coliform bacteria 1.6 × 10³–2.0 × 10⁴ cfu mL⁻¹). Suspended solids exceeded the limit values by 10–50 times, organic matter by 10–25 times, dissolved organic carbon by 3–5 times, nitrogen by 3–7 times, total phosphorus by 3–12 times, and microorganisms by 3–10 times. UV/Vis limit values calculated were as follows: A210 nm—3.997–4.009 cm⁻¹, A 240 nm—5.193–5.235 cm⁻¹, A254 nm—4.042–4.047 cm⁻¹, A320 nm—7.387–7.406 cm⁻¹, and A 660 nm—3.937–3.946 cm⁻¹. UV/Vis measurements at A320 nm are proposed for the routine water quality monitoring.

A. Panchenko, A. Voloshina, I. Panchenko et al.

The reliability of orbital hydraulic motors which are used in mechatronic systems with a hydraulic drive for active working tools on self-propelled machinery is a pressing engineering problem. To increase the reliability, a specific design method was proposed. It required development of a mathematical apparatus and a calculation algorithm. The mathematical tools allowed to realize the method for determination of hydraulic motor reliability by simulating changes in a technical state of the rotors in a hydraulic motor. A program, which has been developed, enabled modeling the conjugation of external and internal rotors. The program implemented an algorithm for the sequence of calculating the parameters for the external and internal rotors. The proposed program made it possible to obtain a three-dimensional image of zones with admissible interfaces which ensure the efficient and reliable operation of orbital motors. The modeling of working capacity change for an orbital motor has established some dependence. The changes in the number of teeth and overall dimensions of the rotor in the investigated range enabled to develop a standard size range for hydraulic machines, which operate in mechatronic drive systems for active working tools on self-propelled machinery.

Velibor Karanović, M. Jocanović, S. Baloš et al.

0 INTRODUCTION It is very difficult to predict and precisely determine the impact of fluid cleanliness on the system operation or its components, due to many factors and a variety of hydraulic system applications. The hydraulic fluid contamination is an issue that can shorten the working life of hydraulic components, which has a direct impact on maintenance costs [1] to [3]. Also, contamination can be considered as a hydraulic system “intruder”, which has a direct or indirect influence on system behaviour and parameters such as precision, response time, repeatability, controllability, etc. [4] and [5]. Many well-regarded companies and other institutions dealing with manufacturing, maintenance and testing of hydraulic systems and equipment, based on their own experience from practice and experimental research, claim that the working fluid contamination represents the main cause of failures in 70 % to 80 % cases [2] and [6] to [9]. Additionally, the requirements for more precise control and higher efficiency of hydraulic systems, have resulted in the decreased clearances between working elements of hydraulic components and the increased working pressure values [10]. Due to the decreased clearance size, the adverse impact of micron-size solid contaminants becomes evident. Although it is wellknown that solid contaminants are destructive to hydraulic system components, as well as to the working fluid itself, there was no internationally accepted method for objectively determination of contamination tolerance for systems or each component separately [11], until 2017. In 2013, was initiated and consequently published ISO 12669:2017 standard, developed for determining the required cleanliness level (RCL) for a system [12]. This standard is now under review for five years period. Due to the lack of a standard procedure, the RCL choice is based on the system designer experience or on the third person recommendation (such as components manufacturer) and his experience. This doesn’t mean that optimal cleanliness level was selected for the specific system operation. The RCL selection by this method is strongly subjective, for which reason it does not provide consistency. Consequently, many system designers, as well as the users of hydraulic systems, are unsure and confused about the appropriate cleanliness level Impact of Contaminated Fluid on the Working Performances of Hydraulic Directional Control Valves Karanović, V. – Jocanović, M. – Baloš, S. – Knežević, D. – Mačužić, I. Velibor Karanović1,* – Mitar Jocanović1 – Sebastian Baloš1 – Darko Knežević2 – Ivan Mačužić3 1University of Novi Sad, Faculty of Technical Sciences, Serbia 2University of Banja Luka, Faculty of Mechanical Engineering, Bosnia and Herzegovina 3University of Kragujevac, Faculty of Engineering, Serbia

Vahdettin Demir, O. Kisi

In this study, flood hazard maps were prepared for the Mert River Basin, Samsun, Turkey, by using GIS and Hydrologic Engineering Centers River Analysis System (HEC-RAS). In this river basin, human life losses and a significant amount of property damages were experienced in 2012 flood. The preparation of flood risk maps employed in the study includes the following steps: (1) digitization of topographical data and preparation of digital elevation model using ArcGIS, (2) simulation of flood lows of different return periods using a hydraulic model (HEC-RAS), and (3) preparation of flood risk maps by integrating the results of (1) and (2).

Bahador Fatehi-Nobarian, Hooman Hajikandi, Yousef Hassanzadeh et al.

Fluid dynamics aims at understanding the movement of liquids and gases by functions that describe the distribution of velocities. In the present study, the characteristics of secondary currents in trapezoidal channels with side angles of 45, 60 and 75° subjected to the influence of five different discharges with experimental tests, are investigated and the results are compared with that of Flow3D. The results obtained from experimental measurements and numerical models comparison of the rate of secondary currents in different Froude numbers demonstrated that there exists an opposite relationship between the secondary velocity in the direction of perpendicular to the axis of flows (Vx) and velocity in a direction perpendicular to the flow level (Vz) in trapezoidal channels. Moreover, at 45° angle, there has been a remarkable energy loss during hydraulic jump. The ratio of the increase in the secondary currents velocity in X direction in Froude number 10 of 45° angle is higher than that of two other sections, which is equal to 71%, compared to 75° angle in numerical models and in Froude number 9 it was 91% during experimental tests. Then, the secondary currents velocity in Z direction for Froude number 2 of 75° angle is higher than that of two other sections, which is 88%, compared to the 45° angle in numerical models and in Froude number 1.5 it was equal to 74.5% for experimental tests.