Yellow River Institute of Hydraulic Research

This review summarizes the recent progress in the design, fabrication, and application of visible light-responsive photocatalysts.

Abstract By trapping sediment in reservoirs, dams interrupt the continuity of sediment transport through rivers, resulting in loss of reservoir storage and reduced usable life, and depriving downstream reaches of sediments essential for channel form and aquatic habitats. With the acceleration of new dam construction globally, these impacts are increasingly widespread. There are proven techniques to pass sediment through or around reservoirs, to preserve reservoir capacity and to minimize downstream impacts, but they are not applied in many situations where they would be effective. This paper summarizes collective experience from five continents in managing reservoir sediments and mitigating downstream sediment starvation. Where geometry is favorable it is often possible to bypass sediment around the reservoir, which avoids reservoir sedimentation and supplies sediment to downstream reaches with rates and timing similar to pre‐dam conditions. Sluicing (or drawdown routing) permits sediment to be transported through the reservoir rapidly to avoid sedimentation during high flows; it requires relatively large capacity outlets. Drawdown flushing involves scouring and re‐suspending sediment deposited in the reservoir and transporting it downstream through low‐level gates in the dam; it works best in narrow reservoirs with steep longitudinal gradients and with flow velocities maintained above the threshold to transport sediment. Turbidity currents can often be vented through the dam, with the advantage that the reservoir need not be drawn down to pass sediment. In planning dams, we recommend that these sediment management approaches be utilized where possible to sustain reservoir capacity and minimize environmental impacts of dams.

Different types of public–private partnerships (PPPs) have been practiced in worldwide infrastructure development with diverse results and a variety of problems have been encountered. A number of factors combine to determine the success or failure of an infrastructure project in terms of its objectives. There is an urgent need for a workable and efficient procurement protocol for improved practices in future PPP projects. As an important step toward the development of such a protocol, this study identifies, analyzes, and categorizes various critical success factors (CSFs) for PPPs in general based on a public–private win–win principle and a systematic research approach that includes case studies, literature review, and interviews/correspondence with international experts. A CSF package is developed that contains five main CSFs, each including a number of success subfactors (SSFs). Relative significances of these CSFs and SSFs are examined based on the results of a questionnaire survey of international expert opinions. Agreement analysis shows that there is a good agreement in the ranking of these CSFs and SSFs between respondents from the industrial sector and those from the academic sector.

A one‐year study was carried out to investigate the seasonal fluxes and source variation of organic carbon transported by two major Chinese rivers, the Yellow River and Changjiang. In 2009, the Yellow River and Changjiang transported 3.20 × 10 10 g and 1.58 × 10 12 g DOC and 3.89 × 10 11 g and 1.52 × 10 12 g POC, respectively. The dominant input of the terrestrial organic matter occurred during the high discharge period from June to July for the Yellow River and from June to August for Changjiang, accounting for 36–44% of the DOC and 72–86% of the POC transported by the two rivers in 2009. The Yellow River transported much higher concentrations of inorganic carbon than organic carbon, while a reverse trend was found in the Changjiang, indicating the different sources of carbon discharged by the two rivers. Using radiocarbon and stable carbon isotope measurements, we identified the different sources and seasonal variations of organic carbon transported by the Yellow River and Changjiang. The Yellow River carried old POC with radiocarbon ages ranging from 4000 to 8000 years, while POC transported by Changjiang had a relatively younger 14 C age ranging from 800 to 1060 years. The 14 C ages of DOC were relatively younger (305–1570 years) and showed less variation between the two rivers. The seasonal variations found in 14 C ages of DOC and POC indicate that a large fraction of recent‐fixed labile organic carbon was transported by the two rivers in the spring and summer months. The different sources and seasonal variations in both fluxes and sources of organic carbon transported by the Yellow River and Changjiang could have an important influence on the biogeochemical cycle and ecosystems in the estuaries and adjacent coastal waters of the East China Sea.

BACKGROUND: Soil salinization threatens food security and ecosystem health, and is one of the important drivers to the degradation of many ecosystems around the world. Soil microorganisms have extremely high diversity and participate in a variety of key ecological processes. They are important guarantees for soil health and sustainable ecosystem development. However, our understanding of the diversity and function of soil microorganisms under the change of increased soil salinization is fragmented. AIM OF REVIEW: Here, we summarize the changes in soil microbial diversity and function under the influence of soil salinization in diverse natural ecosystems. We particularly focus on the diversity of soil bacteria and fungi under salt stress and the changes in their emerging functions (such as their mediated biogeochemical processes). This study also discusses how to use the soil microbiome in saline soils to deal with soil salinization for supporting sustainable ecosystems, and puts forward the knowledge gaps and the research directions that need to be strengthened in the future. KEY SCIENTIFIC CONCEPTS OF REVIEW: Due to the rapid development of molecular-based biotechnology (especially high-throughput sequencing technology), the diversity and community composition and functional genes of soil microorganisms have been extensively characterized in different habitats. Clarifying the responding pattern of microbial-mediated nutrient cycling under salt stress and developing and utilizing microorganisms to weaken the adverse effects of salt stress on plants and soil, which are of guiding significance for agricultural production and ecosystem management in saline lands.

Assessment of ecoenvironmental vulnerability plays an important role in the guidance of regional planning, the construction and protection of ecological environment, which requires comprehensive consideration on regional resources, environment, ecology, society and other factors. Based on the driving mechanism and evolution characteristics of ecoenvironmental vulnerability in cold and arid regions of China, a novel evaluation index system on ecoenvironmental vulnerability is proposed in this paper. For the disadvantages of conventional entropy weight method, an improved entropy weight assessment model on ecoenvironmental vulnerability is developed and applied to evaluate the ecoenvironmental vulnerability in western Jilin Province of China. The assessing results indicate that the model is suitable for ecoenvironmental vulnerability assessment, and it shows more reasonable evaluation criterion, more distinct insights and satisfactory results combined with the practical conditions. The model can provide a new method for regional ecoenvironmental vulnerability evaluation.

By sequencing 727 ancient individuals from the Southern Arc (Anatolia and its neighbors in Southeastern Europe and West Asia) over 10,000 years, we contextualize its Chalcolithic period and Bronze Age (about 5000 to 1000 BCE), when extensive gene flow entangled it with the Eurasian steppe. Two streams of migration transmitted Caucasus and Anatolian/Levantine ancestry northward, and the Yamnaya pastoralists, formed on the steppe, then spread southward into the Balkans and across the Caucasus into Armenia, where they left numerous patrilineal descendants. Anatolia was transformed by intra-West Asian gene flow, with negligible impact of the later Yamnaya migrations. This contrasts with all other regions where Indo-European languages were spoken, suggesting that the homeland of the Indo-Anatolian language family was in West Asia, with only secondary dispersals of non-Anatolian Indo-Europeans from the steppe.

High-quality development (HQD) is the requirement for adapting to the changes in the main contradictions of Chinese society and achieving sustained and stable development. Based on the discussion of its connotation, this study constructed an evaluation model covering five aspects of society, economy, resources, ecology, and culture. Then we used the obstacle diagnosis model to analyze the main obstacle factors of restricting the improvement of HQD level. Finally, 4 future policy scenarios were designed under the system dynamics (SD) model to simulate the variation of the future development in each province along the Yellow River Basin (YRB). The results show that: (1) The level of HQD in the YRB changed dynamically over time, and it has also improved to varying degrees in all provinces. (2) The cultural subsystem hindered the further improvement of the HQD; for the indicator layer, the proportion of cultural industry in GDP is the main obstacle factor for most provinces. (3) Speeding up economic development and increasing ecological protection is the optimal development path of the YRB. Scientific evaluation of the regional HQD status and simulating the development situation under different scenarios can improve the accuracy and efficiency of managers’ decision-making.

Due to the continuous and adverse effects of microplastics on the environment, an increasing number of studies have begun to focus on their migration patterns and removal from aquatic environments. Herein, our study innovatively evaluated the ability of the capacity of ZIF-67, a novel metal-organic framework (MOF) material, to adsorb polystyrene (PS) microplastics (MPs) from aqueous solutions, aiming to explore the potential of MOF materials to remove MPs from wastewater. The adsorption ratio of PSMPs (5 mg/L, 30 mL) by ZIF-67 reached up to 92.1%, and the PSMP adsorption equilibrium was achieved within 20 min at 298 K. The adsorption of PSMPs would be favored at a pH of 8, a PSMPs solution concentration of 5 mg/L, and a temperature of 298 K. Further analyses demonstrated that hydrogen bond interactions, π-π stacking, and electrostatic interactions played a crucial role in the adsorption of PSMPs by ZIF-67 in aqueous solutions. Our findings thus provide insight into novel methods to remove MPs from acidic and weakly alkaline aquatic environments and wastewater.

Numerous public infrastructure projects have been privatized worldwide, where responsibilities, risks, and rewards are substantially reallocated between pubic and private sectors. The financial evaluation of a privatized infrastructure project is complex and challenging because of the risks and uncertainties due to the large size, long contract duration, nonrecourse financing, multiple project participants with different motives and interest, and the complexity of the contractual arrangements. Improved financial engineering techniques are required to overcome the limitations of traditional financial analysis techniques in addressing risks and uncertainties. This paper develops a methodology for capital structure optimization and financial viability analysis that reflects the characteristics of project financing, incorporates simulation and financial engineering techniques, and aims for win–win results for both public and private sectors. This quantitative methodology defines the capital structure of a privatized project in four dimensions, examines different project participants’ perspectives of the capital structure, optimizes the capital structure, and evaluates the project’s financial viability when it is under construction risk, bankruptcy risk and various economic risks (that are dealt with as stochastic variables), and is subject to other constraints imposed by different project participants. This methodology also evaluates the impact of governmental guarantees and supports, and addresses the issue of the equity holders’ commitment to project success by initiating the concepts of equity at project risks, value of governmental loan guarantee, and project bankrupt probability during construction. A framework and a solution algorithm are provided for this proposed methodology. These research outputs will significantly facilitate both public and private sector in evaluating a privatized project’s financial viability and collectively determining an optimal capital structure that safeguards their respective interests.

Infrastructure privatization has multidimensional impacts with long-term uncertainties and wide risk portfolios. A wide range of barriers to public–private partnerships (PPPs) in infrastructure development have been identified through a questionnaire survey, which are broadly classified into six aspects: (1) social, political, and legal risk; (2) unfavorable economic and commercial conditions; (3) inefficient public procurement framework; (4) lack of mature financial engineering techniques; (5) problems related to the public sector; and (6) problems related to the private sector. To explore measures for removing these barriers, a systematic research approach (literature review, case studies and interviews/correspondences with experts and experienced practitioners) has been taken to draw experience, learn lessons, and benchmark the best practices in international PPPs. An improved PPP protocol for infrastructure projects in general has been developed, addressing key issues in nine areas: (1) appropriate roles of governmental authorities; (2) best value for money approach; (3) effective management of adviser services; (4) formulation of appropriate PPP schemes; (5) use of relational contracts; (6) improvement of the procurement framework; (7) payment structure; (8) contract monitoring, termination, and step-in rights; and (9) transfer management. Effective measures for successful PPPs are identified in each of the nine areas.

An environmental friendly recycling method of waste lithium ion batteries use <sc>d</sc>,<sc>l</sc>-malic acid through reducing-complexing process.

Irrigation agriculture is a major economic activity throughout the Yellow River Basin and has doubled in area in the last 5 decades. Monitoring data for major ions at 63 monitoring stations in the Yellow River system, ranging from 1960 to 2000, were studied. The concentration of major ions in much of the basin, and especially in downstream of the major irrigation areas of the upper basin, increases significantly between 1960 and 2000. We conclude that this increasing trend is mainly a result of saline irrigation return waters, especially from irrigated lands in arid zones of northern China where sodium increases by 100% and total dissolved solids increases by 29% in the main stem. Since 1972 a critical water quantity issue, “duanliu,” has appeared, which refers to the drying up of the lower reach of the Yellow River. This phenomenon is due mainly to increasing irrigation water withdrawal, which is officially reported to be 91% of all surface water abstraction from the Yellow River. High rates of evapotranspiration and loss to groundwater, especially in the arid irrigated areas in two large irrigation areas in Ningxia and Inner Mongolia, where abstracted water is some 25–30% of annual main stem flow, creates major water losses. There is a need to develop and enforce more rational water quotas as part of a reform of water management in the basin so that basin‐wide management is given at least as much importance as provincial‐level benefits.

Geopolymer recycled aggregate concrete (GPRAC) is a new type of green material with broad application prospects by replacing ordinary Portland cement with geopolymer and natural aggregates with recycled aggregates. This paper summarizes the research about the mechanical properties, durability, and microscopic aspects of GPRAC. The reviewed contents include compressive strength, elastic modulus, flexural strength, splitting tensile strength, freeze-thaw resistance, abrasion resistance, sulfate corrosion resistance, and chloride penetration resistance. It is found that GPRAC can be made to work better by changing the curing temperature, using different precursor materials, adding fibers and nanoparticles, and setting optimal mix ratios. Among them, using multiple precursor materials in synergy tended to show better performance compared to a single precursor material. In addition, using modified recycled aggregates, the porosity and water absorption decreased by 18.97% and 25.33%, respectively, and the apparent density was similar to that of natural aggregates. The current results show that the performance of GPRAC can meet engineering requirements. In addition, compared with traditional concrete, the use of GPRAC can effectively reduce carbon emissions, energy loss, and environmental pollution, which is in line with the concept of green and low-carbon development in modern society. In general, GPRAC has good prospects and development space. This paper reviews the effects of factors such as recycled aggregate admixture and curing temperature on the performance of GPRAC, which helps to optimize the ratio design and curing conditions, as well as provide guidance for the application of recycled aggregate in geopolymer concrete, and also supply theoretical support for the subsequent application of GPRAC in practical engineering.

A critical issue in public–private partnerships (PPPs) in international infrastructure development is the selection of the right private-sector partner. This necessitates a best value source selection methodology in which the establishment of a set of appropriate selection criteria is a prerequisite. Various important selection criteria have been identified through a literature review of previous studies on critical success factors; experience drawing and lessons learning from international PPP practices; examination of selection criteria used in worldwide PPP projects; and interviews/correspondence with international PPP experts and practitioners. These identified criteria are classified into four evaluation packages for PPP projects in general: (1) financial, (2) technical, (3) safety, health, and environmental, and (4) managerial. The relative importance of these evaluation packages and the relative significance of the criteria within each package have been statistically analyzed based on a structured questionnaire survey of worldwide PPP expert opinions. These statistical analyses include validity and reliability analysis, Mann Whitney U tests, direct comparisons of mean criterion significance indexes and criterion rankings between respondents across public, private, and academic sectors, and a general rank agreement analysis across sectors for each evaluation package. These research outputs would facilitate the formulation of a multicriteria best value source selection methodology for PPP projects in general and the development of both objective and subjective evaluation criteria to select the right private-sector partner for a particular PPP project.

Global warming has become a major concern for countries around the world. In this context, developed countries have decided to reduce global emissions to achieve sustainable development. The energy mix of OECD countries consists of 80% fossil fuels and accounts for about 35% of worldwide carbon emissions. Therefore, it is important to analyze how environmental factors affect carbon emissions in OECD countries. This study uses fossil energy, renewable energy (RE), and GDP for the period 1990–2019. Unlike previous studies, we will estimate two separate models for FFE and RE. To evaluate the empirical results, advanced panel data estimation methods using the cointegration test and the CS-ARDL estimation technique are employed to examine the long-run relationship between the variables. The results of the study demonstrate that fossil fuel use and GDP increase carbon emissions both in the short and long term. However, the use of RE hurts carbon emissions and is associated with sustainable development in OECD countries. Therefore, it is assumed that although fossil fuel use degrades the environment, economic growth helps it by reducing carbon emissions. Overall, our study shows that the use of RE is essential for OECD countries to achieve their environmental sustainability goals because it reduces the share of fossil fuels in the overall energy mix. Furthermore, in order to achieve a sustainable environment, OECD countries are recommended to begin long-term planning to reduce carbon emissions.

Abstract Water in motion presented in natural systems contains a rich source of renewable mechanical energy. Harvesting this water energy to trigger the generation of reactive oxygen species (ROS) for water purification is a desirable yet underexplored solution. Herein, the authors report a self‐powered water motion triggered Fenton‐like reaction system for wastewater treatment through the piezo‐activation of peroxymonosulfate (PMS). Isolated protrudent Fe single atomic sites are immobilized on the surface of molybdenum disulfide (MoS 2 ) nanosheet to improve piezoelectric polarization of MoS 2 , to accelerate piezoelectric charge separation, and to enhance PMS activation for water purification. ROS ( • OH, SO 4 •− , O 2 •− , and 1 O 2 ) generation for PMS piezo‐activation are observed, and different water contaminants, including antibiotic, industrial chemicals, and dyes are efficiently removed under the natural water fluid. Aimed at solving concurrent issues of environmental pollution and energy crisis, this study provides a pathway for single atomic‐mediated piezo‐activation of Fenton‐like reactions through ambient self‐powered water motion for water purification.

Literary and archaeological sources have preserved a rich history of Southern Europe and West Asia since the Bronze Age that can be complemented by genetics. Mycenaean period elites in Greece did not differ from the general population and included both people with some steppe ancestry and others, like the Griffin Warrior, without it. Similarly, people in the central area of the Urartian Kingdom around Lake Van lacked the steppe ancestry characteristic of the kingdom's northern provinces. Anatolia exhibited extraordinary continuity down to the Roman and Byzantine periods, with its people serving as the demographic core of much of the Roman Empire, including the city of Rome itself. During medieval times, migrations associated with Slavic and Turkic speakers profoundly affected the region.

With the development of deep learning, change detection technology has gained great progress. However, how to effectively extract multi-scale substantive changed features and accurately detect small changed objects as well as the accurate details is still a challenge. To solve the problem, we propose Attentived Differential High-Resolution Change Detection Network (ADHR-CDNet) for remote sensing images. In ADHR-CDNet, a novel high-resolution backbone with a Differential Pyramid Module (DPM) is proposed to extract multi-level and multi-scale substantive changed features. The backbone structure with four interconnected sub-network branches of different resolution is helpful to extract multi-level and multi-scale features. DPM is capable of distinguishing between substantive changes and pseudo changes induced by illumination, shadow, seasonal variation, and so on. Then, a novel Multi-Scale Spatial feature Attention Module (MSSAM) is presented to effectively fuse the spatial detail information of different scale features produced by our backbone to generate finer prediction. We conduct quantitative and qualitative experiments on three public change detection datasets: the Lebedev, the LEVIR-CD, and the WHU Building dataset. The proposed ADHR-CDNet reaches F1-score of 97.2% (improved 3.1%) on the Lebedev dataset, 91.4% (improved 1.6%) on the LEVIR-CD dataset, and 90.9% (improved 1.2%) on the WHU Building dataset. The experimental results demonstrate that our method performs much better than the state-of-the-art methods. The visualization comparison results show that our method can effectively detect small changed objects and significantly improve the details of detected changed objects. Our code is available at https://github.com/w-here/ASGO-113lab/tree/main/ADHR-CDNet.

Abstract. Conventional streamflow models operate under the assumption of constant variance or season-dependent variances (e.g. ARMA (AutoRegressive Moving Average) models for deseasonalized streamflow series and PARMA (Periodic AutoRegressive Moving Average) models for seasonal streamflow series). However, with McLeod-Li test and Engle's Lagrange Multiplier test, clear evidences are found for the existence of autoregressive conditional heteroskedasticity (i.e. the ARCH (AutoRegressive Conditional Heteroskedasticity) effect), a nonlinear phenomenon of the variance behaviour, in the residual series from linear models fitted to daily and monthly streamflow processes of the upper Yellow River, China. It is shown that the major cause of the ARCH effect is the seasonal variation in variance of the residual series. However, while the seasonal variation in variance can fully explain the ARCH effect for monthly streamflow, it is only a partial explanation for daily flow. It is also shown that while the periodic autoregressive moving average model is adequate in modelling monthly flows, no model is adequate in modelling daily streamflow processes because none of the conventional time series models takes the seasonal variation in variance, as well as the ARCH effect in the residuals, into account. Therefore, an ARMA-GARCH (Generalized AutoRegressive Conditional Heteroskedasticity) error model is proposed to capture the ARCH effect present in daily streamflow series, as well as to preserve seasonal variation in variance in the residuals. The ARMA-GARCH error model combines an ARMA model for modelling the mean behaviour and a GARCH model for modelling the variance behaviour of the residuals from the ARMA model. Since the GARCH model is not followed widely in statistical hydrology, the work can be a useful addition in terms of statistical modelling of daily streamflow processes for the hydrological community.