Hasil untuk "Hydraulic engineering"

João Caetano, Nelson Carriço, Bruno Brentan et al.

Abstract This paper presents a topology‐aware neural network approach for the detection, location, and quantification of abnormal consumptions in water distribution networks. The approach includes two main steps: the optimization of pressure sensor locations to maximize measurement sensitivity and the development of metamodels based on near real‐time data. The metamodel is designed and trained to predict the consumptions at all nodes based on pressure measurements and users' consumption collected by smart meters. These nodal consumptions deduced from the actual measured consumption allow the location of potential abnormal uses in the network. The proposed methodology enables the development of two metamodels, each tailored to specific applications based on the training data. The Static Metamodel relies on pressure head measurements under the assumption of constant nodal consumption, whereas the Dynamic Metamodel accounts for daily consumption variations, enabling the detection and location of abnormal consumption in real‐world scenarios. Both metamodels can detect the location of abnormal consumptions with reasonable accuracy, although this accuracy strongly depends on the number and spatial distribution of sensors, as well as the magnitude and location of the abnormal consumption. As water utilities implement advanced metering systems, the application of the proposed approach becomes more viable, enabling more effective and faster abnormal consumption detection.

Ian Cunningham, Juliet Willetts, Tim Foster et al.

Motivated volunteer water committees are central to the effectiveness of community-based management (CBM) approaches to rural drinking water supply. CBM is the predominant approach to managing rural drinking water supplies, particularly in low-income countries. In CBM, it is assumed that a community’s interest in a sustained water supply will motivate them to take on water supply management responsibilities. However, in practice and in the academic literature, Water Point Committee (WPC) members’ motivations have been oversimplified and are poorly understood. This paper uses Self-Determination Theory (SDT), a theory of motivation, to analyse the types and quality of WPC members’ motivations across six rural locations in Malawi. We found a wider range and quality of motives than has been documented in the literature. WPC members’ autonomous, higher-quality motives included personal benefits from an improved water supply service, the pro-social nature of the committee role, an interest in learning and working with others, and positive changes in self-esteem. Lowerquality motives were experienced as feelings of being pressured and included continued committee participation to avoid shame or to avoid disappointing others. Our study findings show the relevance of SDT in providing a more nuanced understanding of what drives WPC members’ commitment to water management responsibilities. This understanding of, and support for, members’ motivations is critical for sustaining community-based rural water supply services.

Yingbin Song, Xiangping Zhang, Jinxia Xu et al.

The low pozzolanic activity of the silt in the Yellow River has always been the key factor that hinders its resource utilization as artificial stones. A high-speed ball-milling method was first attempted to pretreat the silt for enhancing its pozzolanic activity in this study. The artificial stones incorporating the ball-milled silt were prepared by the alkali-activation method. The changes in the basic physical and chemical properties and microstructures of the pre-treated silt and fabricated artificial stones were characterized. Also, the compressive strength, splitting tensile strength and water resistance of fabricated specimens were measured. The results show that the ball-milling treatment destroys the original crystal structure, and significantly enhances the potential pozzolanic activity of the silt. In addition, it improves the compressive strength, splitting tensile strength and water resistance of the artificial stones. The compressive strength of artificial stones incorporated with the ball-milled silt has a maximum value of 17.1 MPa, showing an increase by one time. It can be ascribed to the increase of C-S-H/C-A-S-H gel amount in specimens. Furthermore, compared to traditional mined bluestone, the carbon emission of the alkali-activated artificial stone incorporating ball-milled Yellow River silt is much lower. The production of 1 t of artificial stone only emits 1155.25 kg of CO2.

Paul van Wiechen, Jantien Rutten, Sierd de Vries et al.

Abstract Nearshore hydro- and morphodynamic data were collected during a field experiment under calm conditions, moderate conditions, and storm conditions with dune erosion in the collision regime. The experiment was conducted on the Sand Engine near Kijkduin, the Netherlands, from October 18, 2021, to January 7, 2022. Two artificial unvegetated dunes were constructed just above the high water line to measure storm erosion and dune impacts from higher water levels and waves. During the experiment, three storms occurred that resulted in significant erosion of both dunes. The collected hydrodynamic data include pressure sensor and velocimeter data along two cross-shore transects. The collected morphodynamic data include bathymetry and topography surveys, optical backscatter sensor data in the inner surf zone, and a continuous cross-shore line-scanning lidar data set of the dune face. This comprehensive data set can be used to (1) study relevant nearshore hydrodynamic and morphodynamic processes that occur during calm conditions, moderate conditions, and storm conditions with dune erosion in the collision regime, and (2) validate existing dune erosion models.

Shaolong Zheng, Kungan Zeng, Zhenni Li et al.

Signals from global navigation satellite systems (GNSSs) in urban areas suffer from serious multipath errors caused by building blockages and reflections. The use of deep neural networks offers great potential for predicting and eliminating complex multipath/non-line-of-sight (NLOS) errors. However, existing methods for predicting the original signals face two remaining challenges. The first challenge is an inability to effectively exploit irregular GNSS measurement data caused by an inconsistent number of visible satellites in different epochs. The second challenge is degradation in the generalization performance of the multipath/NLOS prediction model when using data collected from different locations and periods. To address these challenges, this paper proposes a novel graph transformer neural network (GTNN) for predicting satellite visibility that effectively learns environment representations from irregular GNSS measurements to both alleviate multipath interference and improve the generalization performance of the multipath prediction model. To learn from irregular GNSS measurements, a sky satellite graph is constructed as input to a graph neural network by using satellites captured in the same epoch, which can represent the spatial relationships between satellites and enable the model to learn satellite-related features sufficiently well. To improve the generalization ability of our multipath prediction model, a multihead attention mechanism is introduced to aggregate satellite node information by computing the correlation between satellites to extract the environment representation around the receiver. Based on the constructed sky satellite graph and the multihead attention mechanism, our novel GTNN for predicting satellite visibility can not only handle irregular GNSS measurements but can also learn an environment representation via graph attention. Comparative experiments were conducted on real-world GNSS measurement data in urban areas, demonstrating that the proposed method can achieve an accuracy exceeding 96% for satellite visibility prediction and obtain better generalization performance than existing multipath prediction methods. Moreover, the attention weights among satellites were visualized to demonstrate the environment representation learned by the GTNN from the sky satellite graph.

Zhanling Li, Wen Li, Zhanjie Li et al.

Understanding the impact of climate change on runoff and its extremes is of great significance for water resource assessment and adaptation strategies, especially in water-scarce regions. This study aims to analyze the impact of future climate change on runoff and its extremes in the upper reaches of the Heihe River basin in northwest China. The projected runoff was derived using the Soil Water Assessment Tool with climate data from the CSIRO-MK-3-6-0 model under the scenario of RCP4.5, and a frequency analysis of runoff was performed by generalized extreme value distribution. The results indicate that, compared with the baseline period of 1961 to 2000, the minimum and maximum temperatures in the period 2031 to 2070 were predicted to increase by 2.5 °C on average. The precipitation in most months was also predicted to increase, with an average rise of 16.5%. The multi-year average runoff was projected to increase by 8%. The annual mean and extreme flows were also expected to rise under future climate change at different return periods, and the low flow was expected to increase the most.

Wei Liu, Yingchao Ma, Jinqing Jia

Due to the high compressive strength and durability of ultra-high-strength concrete, SRUHSC (steel-reinforced ultra-high-strength concrete) frame structures have been used extensively in super-high-rise buildings. However, the SRUHSC showed obvious brittleness. Encasing structural steel in the material was recognized to be a good way of alleviating the problem of brittleness. The purpose of this study is to investigate the effect of the axial compression ratio on the seismic performance of a single-story, single-span SRUHSC frame structure under rapid loading. The failure mode, deformation, strength and stiffness degradation, energy dissipation capacity and residual displacement of the structure were compared and analyzed. The seismic performance of a single-story single-span SRUHSC frame structure is verified under the conditions of a fast loading rate and high axial compression ratio. The results suggest that the horizontal resistance capacity of structures can be significantly improved by fast loading in the elastic and elastic–plastic ranges. The ductility coefficient of the structure increases with the same axial compression ratio under fast loading. With an increase in loading rate, the secant stiffness of the structure is improved.

Linlin Fang, Mengyuan Dong, Wenbo Fang et al.

ObjectivesThis study aims to explore the potential mediating role of resilience between care burden and depressive symptoms in family caregivers of stroke patients.MethodsA cross-sectional study was conducted with a convenience sample involving 245 main family caregivers of stroke patients recruited from the neurology department of a Tertiary A hospital in China. Mediation analyses were conducted using the PROCESS macro (Model 4) for SPSS, applying the Bootstrap analysis with 5,000 samples and a 95% confidence interval.ResultsThe results showed that with constant hemiplegia side, Barthel Index, education level, monthly income, care time per day, and living with patients in regression equations, the resilience partially mediated the correlation of care burden and depressive symptoms with a mediation effect ratio of 26.32%.ConclusionsResilience plays a mediating role in the correlation between care burden and depressive symptoms.ImpactThe findings indicated a protective effect of resilience in alleviating the negative influences of care burden on depressive symptoms, suggesting that resilience-training intervention may be developed to mitigate depressive symptoms of the main family caregivers of stroke patients.

Iraj Vayskarami, Kianfar Payamani, Maryam Sadat Jaafarzadeh

Introduction One of the main goals of spatial analysis of precipitation at area is to reach the standard project storm (SPS) for that area, through which can be reached the standard project flood (SPF). This analysis includes the characteristics of rainfall depth at a certain area and for a specific duration. Relation between depth and rainfall area which called depth-area-duration (DAD), is shown usually by set of curves that each shows different duration of rainfall. Using these curves, a reduction factor is determined for specific area and is applied to adjust the average point rainfall related to frequency of this project. The present study carried out under topic of investigation and map of depth- area- duration in Lorestan, in an area over 28559/5 Km2 in west part of country.Materials and Methods Weak coefficient of correlation is shown meaningfulness of the relation between rainfall and altitude in different time base. this is resulted from different reasons such as extension of area, lack of transmittal and number of suitable weather stations and different extension and tension of mountain than rain flaw. Considering above points cause those other methods of drawing precipitation maps include interpolation or geostatistical methods including, spline, IDW, kriging and Co-kriging were used.Results and Discussion Weak coefficient of correlation is shown meaningfulness of the relation between rainfall and altitude in different time base. this is resulted from different reasons such as extension of area, lack of transmittal and number of suitable weather stations and different extension and tension of mountain than rain flaw. Considering above points cause those other methods of drawing precipitation maps include interpolation or geostatistical methods including, spline, IDW, kriging and Co-kriging were used.Conclusion The results show that to preparing precipitation maps of selecting storms, simple co- kriging (SCK) is a suitable method to calculate the amount of rainfall of selecting storms in lorestan province. So the above way is used for preparing precipitation maps. Resulted from investigation of surface reduction factor of rain fall shows that in time duration 12 and 48 hrs with the increase of each 5000 surface reduction factor reduces for 0.1 in 24 hrs duration within 18000 Km2. This coefficient has a slow decreasing trend and then that is similar to 12 and 48 hrs rainfalls. Assessing the daily rainfall statistics of some of rain gauge stations in somewhere of the province by the Meteorological Organization and the Ministry of Energy, shows that sometimes there is a significant difference between the perception rates recorded by these organizations. Therefore, in order to eliminate the existing defects, it is suggested that the stations occupied by these organizations and their monitoring status be periodically evaluated by the experts of the relevant organizations and possible defects be prevented.

ZHANG Yan, CHENG Rui, ZOU Lei et al.

【Background and objective】 Groundwater is the most important water resource for agricultural production in many regions around the world and its spatiotemporal changes are affected by a multitude of natural and anthropogenic factors. Understanding their quantitative relationship is hence imperative not only to sustain agricultural production but also to safeguard the development of other sectors. Taking an irrigation district in central China as an example, this paper analyzed the fluctuation of its groundwater depth in response to climate change and anthropogenic activity. 【Method】 The analysis was based on groundwater and meteorological data measured from 1952-2013 from the People’s Victory Canal Irrigation District. Their changes and relationship were analyzed using the decadal volatility analysis, mutation test analysis, gray correlation analysis, sensitivity analysis, double cumulative curve method, and the relative contribution rate method. 【Result】 The groundwater depth in the district has been increasing at an average rate of 0.8 m/10a. The maximum coefficient of variation of the groundwater depth from 1952—1959 was 27.33%; the coefficients of variation of the precipitation, evaporation, average temperature and the amount of irrigation water all peaked in 1960s, though the variation of the evaporation and average temperature was not as strong as other factors. Abrupt changes in groundwater depth, precipitation, evaporation, average temperature and irrigation water amount occurred in 1984, 1970s, 1972, 1973 and 1993—1996, respectively. The influence of each factor on groundwater depth was ranked in the order of average temperature > precipitation > irrigation water amount > evaporation, while the sensitivity of groundwater depth to different factors was ranked in the order of average temperature > evaporation > precipitation > the amount of irrigation water. On average, the contributions of the different factors to groundwater depth change were ranked in the order of average temperature > evaporation > irrigation water amount > precipitation. The average temperature contributed most to the groundwater depth change accounting for 38.16%, and the least was precipitation contributing 17.40%. Irrigation water affected groundwater depth mostly from 2002 to 2013, contributing 47.05% of the change. 【Conclusion】 The factors affecting the groundwater depth in the district varied with time, with evaporation being dominant from 1952 to 1963, average temperature from 1964 to 2001, and irrigation from 2002 to 2013.

Musiba Masamba Musiba, Mwemezi J. Rwiza

This study used the hydrochemical properties of water to reveal the causes of water quality degradation. The results showed that most samples located downstream of the mine tailings dam were slightly acidic with pH as low as 4.6. Samples with high levels of Na+, Cl−, and could not be isotopically linked to the local geochemistry, but the anthropogenic activities and evaporation were probably responsible for the observed water chemistry. The Piper diagram indicated cations were dominated by Ca and Mg, while anions were dominated by bicarbonates and sulphates. Pb and Hg levels (mean 70.29 and 17.95 μg/L, respectively) were all higher than the World Health Organization (WHO) and Tanzanian drinking water guidelines. Mining activities probably contributed to the observed low pH values and elevated concentration of cyanides, heavy metals, and metalloids. Stable isotope results indicated a vulnerability of the water to recent contamination that could be attributed to anthropogenic activities. Moreover, isotopic studies indicated a flow pattern from the eastern to the western side of the mine study site. Lowland samples were more 3H-enriched than highland ones. The present study concludes that groundwater recharge from recent local precipitation may have an impact on the sources studied. HIGHLIGHTS Slightly acidic groundwater in Tanzania.; Levels of Pb and Hg higher than Tanzanian WHO standards.; Vulnerability of groundwater to recent contamination.; Contamination could be linked to local anthropogenic activities.; Contamination increased from east to west, towards Lake Victoria.;

Rahmah Dara Lufira, Lilik Zuhriyah, Satwika Desantina Muktiningsih et al.

Menabung air hujan adalah salah satu upaya untuk mengendalikan kekurangan air dimusim kemarau. Sistem penjernih air hujan menjadi air bersih ini adalah rangkaian kegiatan gerakan menabung air hujan dan menggunakannya kembali untuk konservasi air tanah serta kebutuhan sehari-hari. Desa Arjosari mengalami kekurangan air bersih pada saat musim kemarau, maka dari itu peneliti membuat sistem penjernih air ini dengan memanfaatkan air hujan. Metode yang digunakan adalah tandon air kemudian pipa penjernih yang terdiri dari Zeolit, kerikil, Arang, ijuk dan spoons. Hasil analisa yang telah dilakukan dilaboratorium menggunakan parameter logam metode AAS (atomic absorbance spectrofotometri), parameter anion (spectrofotometer uv vis), dan parameter fisik (water quality checker dan tss meter). Didapatkan rata-rata nilai untuk pH 6.71, TSS 0, TDS 40,3, CaCO3 0, kandungan besi 0,032, Mangan 0,113. Pengujian yang telah dilakukan, mendapatkan hasil yang sesuai dengan persyaratan menurut Peraturan Menteri Kesehatan Republik Indonesia No. 492/MENKES/PER/IV/2010. Sehingga Air yang dipakai memenuhi syarat penggunaan air bersih.

LU Bifeng, DENG Hui, HAO Hao et al.

The high rock slope on the right bank of a hydropower station on Lancang river, which isto be built, is excavated for nearly 400 m.According to the on-site geological survey, the rockmass of the slope is hard and brittle dacite with strong unloading, and small and medium-sizedfaults developed in the slope.In addition, there are two ductile shear zones that dipping towardto the inside slope in the right bank slope,and mylonization occurs in the shear zone, which leadsto the very complex geological conditions and rock mass structure of the right bank slope. Inorder to study the mechanism and rule of deformation response of high rock slope excavation underthis condition, this paper selects the right-bank dam axis slope of hydropower station as theresearch object, and simulates the excavation process of the slope by the UDEC (universal distinctelement code). The results show that:(1) The excavation results in large deformation of theshallow rock mass in the ductile shear zone, which affects the stability of the slope; (2) Thedeformation caused by excavation is mainly controlled by the unloading fissure and overflowsurface that dipping toward to the outside slope, and the geological-mechanical deformation andfailure mode is mainly slipping and fracturing; (3) The slope mainly occurs lateral displacementafter excavation, and its cumulative displacement mode is transmission to high elevation andaccumulation at the trailing edge; (4) The slope excavation and the resulting deformation energyare kept in sync, and finally affected by the elastic recovery lag of rock mass, and the residualdeformation is small near the end of excavation.

Alireza Donyaii, Amirpouya Sarraf, Hassan Ahmadi

In this study, the performance of the algorithms of whale, Differential evolutionary, crow search, and Gray Wolf optimization were evaluated to operate the Golestan Dam reservoir with the objective function of meeting downstream water needs. Also, after defining the objective function and its constraints, the convergence degree of the algorithms was compared with each other and with the absolute optimal values obtained from GAMS nonlinear programming method (19.41). These values together with each algorithm optimization results were ranked using six multi-criteria decision-making methods of TOPSIS, VICOR, Linmap, Codas, ELECTRE and Simple Additive Weighting after obtaining the performance evaluation criteria of each algorithm (Reliability, reversibility, and vulnerability). Finally, integration methods (Mean, Borda, and Copland techniques) were used to evaluate the performance of decision models. The results showed that the mean responses of the gray wolf, the whale, differential evolutionary, and crow search algorithms were 1.08, 1.49, 1.29 and 1.19 times the absolute optimal response and the answers’ coefficient of variation obtained by Gray Wolf algorithm was 113.2, and 1.43 times smaller than the whale, differential evolutionary, and crow search algorithms, respectively. Moreover, all integration techniques indicated the superiority of the gray wolf algorithm. Then, the Crow search, Differential evolutionary, and whale algorithms were ranked second to fourth, respectively. On the other hand, the use of these methods in solving the problem of Golestan Dam reservoir optimization was considered appropriate due to the similarity of the results obtained from the integration techniques with the results of TOPSIS, VICOR and Linmap methods.

Amir Reza Valyani, Naser Feghhi Farahmand, Soleyman Iranzadeh

Today complicated and risky environment makes risk assessment and identification one of the main steps of proper project management and realization of project objectives. Marine construction projects are key and strategic projects, and their specific nature adds to their importance. This study aimed to propose a method for risk assessment and ranking critical risks in marine construction projects in Iran. To this end, the risk assessment team was formed to identify serious marine construction project risks using risk breakdown structure. Afterward, the team defined risk assessment measures. All risks were assessed in each criterion based on the Taguchi loss function. It allowed decision-makers to define a measurable risk threshold for each criterion and assess risks by developing a common language called loss score. Finally, critical risks were determined based on their priority. The results can be used to improve effective risk management, and consequently, project management.

Daniela Martins, Maria Luiza Teofilo Gandini, Nadiane Smaha Kruk et al.

ABSTRACT The objective of this study is to present disaggregation coefficients for intense daily rainfalls for E2-046 rainfall station, located at Caraguatatuba, São Paulo state. The data obtained through rain gauge refer to a continuous period (31 years of series) and had a strong correlation with the measurements of the rain gauge, validating the pluviographs reading, which attributed greater reliability to the results. The average coefficient “24 hours”/“1-day” found for the study region was 1.075, which differs significantly from the values found in literature. The relative deviation considering other durations, and consequently other precipitation coefficients in relation to the mean values of the disaggregation values of the E2-046 station reached 22.06% (18 hours/“24 hours”). The relative deviation of rainfall disaggregation coefficients of the station studied in relation to the mean coefficients for the cities of São Paulo State to small durations was quite high, reaching almost 50% (10 minutes /“24 hours”). This reinforces the need of using local disaggregation coefficients.

Aksoy Aysegul Ozgenc, Bombar Gokcen, Arkis Tanıl et al.

The local scour around bridge piers influences their stabilities and plays a key role in the bridge failures. The estimation of the maximum possible scour depth around bridge piers is an important step in the design of the bridge pier foundations. In this study, the temporal evolution of local scour depths as well as the equilibrium scour depths were analyzed.

D. Ravazzolo, D. Ravazzolo, L. Mao et al.

Large wood transported during extreme flood events can represent a relevant additional source of hazards that should be taken into account in mountain environments. However, direct observations and monitoring of large-wood transport during floods are difficult and scarce. Here we present a video of a flood characterised by multiple phases of large-wood transport, including an initial phase of wood-laden flow rarely described in the literature. Estimations of flow velocity and transported wood volume provide a good opportunity to develop models of large-wood-congested transport.

Carla Maria Salgado Vidal Silva, Marlúcia Freitas Santiago, Mickaelon Belchior Vasconcelos et al.

Medidas de oxigênio-18 e condutividade elétrica, em amostras de águas do açude São Gabriel e de dois poços a 15 e a 80 m do açude, coletadas durante o período de quatro anos e sete meses, foram utilizadas para identificar a existência de conexão hidráulica entre o açude e os poços. A área de estudo localiza-se no distrito de Juá, município de Irauçuba, no Ceará, no domínio de rochas cristalinas. Estas medidas evidenciam a diferença de recarga dos sistemas aqüíferos explorados pelos dois poços. Os resultados mostram que o poço P3 recebe recarga do açude durante o período seco, quando o bombeamento é mais intenso. As águas dos poços sofreram processo de evaporação.

WAN Zhao-hua, ZHANG Zhen, ZHA Zhen-heng