High Inflow Research Articles

Characteristics of reservoirs to mitigate drought effects with a hedging rule triggered by drought limited water level

Droughts constrain environmental, economic, and social development around the world. Reservoir hedging rules are commonly used to reduce the risk of severe water shortages, but the effects are closely related to the characteristic of the reservoir water supply system. Previous studies have limited understanding of the key system characteristics that help to determine whether hedging rules are beneficial for drought mitigation. To fill this gap, this study carries out experiments with a hedging rule triggered by drought limited water level (DLWL). We explore the impact of DLWL on system performance i.e., water supply reliability, resilience, and vulnerability, with a range of hypothetical reservoirs, propose the criterion to decide whether the DLWL is applicable, and identify characteristics of reservoirs where DLWL is not applicable via a scenario discovery method. Three types of reservoirs where DLWL is not applicable are identified. Type Ⅰ and type Ⅱ experience structural deficits. Type Ⅰ is characterized by scarce water resources (m < 0.44) and high inflow uncertainty (Cv > 0.60). Type Ⅱ is mainly characterized by the low reservoir regulation capacity (SI < 0.35). In the type III systems, water demand can always be satisfied and is characterized by the abundance of water resources (m > 0.98) and adequate regulation capacity (SI > 1.02). For the rest of the reservoirs where DLWL is applicable, a multi-objective DLWL optimization method is put forward. Qing River Reservoir in Northeast China is taken as a base case to demonstrate the effectiveness of DLWL and study the influence of changing hydrologic and socioeconomic conditions on optimal seasonal DLWLs. Results indicate that to cope with increasing water supply pressure featured by increasing total demand, decreasing streamflow, and higher streamflow uncertainty, DLWL during the high-water demand periods ought to be raised and DLWL during the dry season that guides water supply for several months ought to be lowered. Insights from this work have general merit for instructing reservoir managers to take effective drought mitigation measures.

Gelişmekte Olan Ülkelerde Kredi Temerrüt Takası (CDS) Primlerinin Belirleyicileri: Türkiye'den Kanıtlar

Turkey faces increasing CDS (Credit Default Swap) spreads. The level of CDS spreads shows the riskiness of a country in terms of credit default and countries can’t attract high foreign investment inflows when CDS spreads are high. In this context, countries need to identify the influential factors in order to decrease CDS spreads. In this study, ten independent variables classified in global, macro, and market factors are analyzed using monthly data between January 2004 and December 2019 with autoregressive distributed lag (ARDL), fully modified least square (FMOLS), dynamic ordinary least square (DOLS), and Markov Switching Regression (MSR) after applying principal component analysis (PCA). The results show that (i) market component has a greater effect than other components for all models, which indicates that it is the most important variable for Turkey’s CDS spreads; (ii) global and market components are positive and statistically significant for the ARDL, FMOLS, and DOLS models; (iii) macro component is negative for all models.

Re-estimation of Keynesian Model by Considering Critical Events and Multiple Cointegrating Vectors

This study employs the Mundell (1963) and Fleming (1962) traditional flow model of exchange rate to examine the long run behaviour of rupee/US $ exchange rate for Pakistan economy over the period 1982:Q1 to 2010:Q2. This study investigates the effect of output levels, interest rates and prices and different shocks on exchange rate. Hylleberg, Engle, Granger, and Yoo (HEGY) (1990) unit root test confirms the presence of non-seasonal unit root and finds no evidence of biannual and annual frequency unit root in the level of series. Johansen and Juselious (1988, 1992) likelihood ratio test indicates three long-run cointegrating vectors. Cointegrating vectors are uniquely identified by imposing structural economic restrictions on purchasing power parity (PPP), uncovered interest parity (UIP) and current account balance. Finally, the short-run dynamic error correction model is estimated on the basis of identified cointegrated vectors. The speed of adjustment coefficient indicates that 17 percent of divergence from long-run equilibrium exchange rate path is being corrected in each quarter. US war with Afghanistan has significant impact on rupee in short run because of high inflows of US aid to Pakistan after 9/11. Finally, the parsimonious short run dynamic error correction model is able to beat the naïve random walk model at out of sample forecasting horizons. JEL Classification: F31, F37, F47 Keywords: Exchange Rate Determination, Keynesian Model, Cointegration, Out of Sample Forecasting, Random Walk Model

Pulmonary hypertension with a precapillary component in heart failure with preserved ejection fraction

ObjectivesHeart failure with preserved ejection fraction (HFpEF) is often complicated by pulmonary hypertension (PH), which is mainly characterised by postcapillary PH and occasionally accompanied by a precapillary component of PH....

New insights into the carbon cycle and depositional models of the Eocene saline lake, Jianghan basin, China

Geochemical characteristics and sedimentary processes of sediments, especially mixed sediments, have long been hot topics of research in basin systems, which can be used to infer runoff, evaporation, productivity, precipitation patterns of the paleoenvironment, as well as records of a diverse range of climate-related signs. However, compared with shallow marine mixed siliciclastic-carbonate sediments, the study of lacustrine mixed sedimentary systems in combination with geochemical information is relatively limited. Also, model-based study on the reconstruction of the lacustrine carbon biogeochemical cycle is defective, especially in saline lacustrine environments. In this work, a total of 26 mixed siliciclastic–carbonate sediment core samples from Well BX-7 in the Qianjiang Depression were sequentially selected for scanning electron microscope observation, major and minor element test, and isotope measurements (e.g., δ13Ccarb, δ18Ocarb, and δ34SCAS). Two types of mixed sediments were generated in the overall inflow/outflow balance of water within the saline basin during the Eocene: siliciclastic-dominated mixed sediment (SDMS) and carbonate-dominated mixed sediment (CDMS). The δ13Ccarb values of SDMS and CDMS samples range from −7.13‰ to −4.52‰ (average −5.82‰) and −9.00‰ to −6.11‰ (average −7.48‰), respectively. The δ18Ocarb values of SDMS and CDMS samples range from −10.26‰ to −1.40‰ (average −4.73‰) and −3.80‰ to −0.96‰ (average −1.55‰), respectively. In addition, combining the geochemical parameters of sedimentation rate, Mn2+ content in carbonate lattice ([Mncarb]), carbonate mass fraction, and [Mg2+]/[Ca2+] ratio, we established a lacustrine δ13C variation model at the sediment-water interface (SWI) with the aim of accurately reflecting δ13Ccarb changes during carbonate formation. Based on the sedimentary processes and geochemical characteristics, we established two depositional models for these two types of mixed sediments in a saline lacustrine basin in the overall inflow/outflow balance of water. Model I illustrates SDMS sedimentary processes with a relative low salinity, low FluxDIC-O, high water inflow, and the organic carbon oxidation is dominated by Fe (III) reduction. Model II demonstrates CDMS sedimentary processes with a high salinity, high FluxDIC-O, high water outflow, and the organic carbon oxidation is dominated by sulfate reduction.

Local identification of groundwater dependent vegetation using high-resolution Sentinel-2 data – A Mediterranean case study

Groundwater dependent ecosystems (GDEs) are biodiversity hotspots and provide important ecosystem services. This study presents a novel multi-instrument concept for the local identification of groundwater dependent vegetation (GDV) in the Mediterranean. The concept integrates high-resolution Sentinel-2 remote sensing data with available geodata and requires in situ vegetation data for validation and calibration. The approach combines five criteria to identify GDV: 1) high vitality, and wetness during dry period, 2) low seasonal changes in vitality and leaf area, 3) low interannual changes in vitality, 4) high topographic potential of water accumulation and low water table depth, 5) high potential inflow dependency. Iso Cluster Unsupervised Classification (ICUC) was applied to identify GDV in the study area (Campania, Italy). Botanical field mapping was utilized for validating the remote sensing approach, as it exhibited significant differences between GDV and Non-GDV in terms of ecohydrological indicator values, leaf anatomy and phreatophyte coverage. According to a new simple ecohydrological rule set that considers phreatophyte cover and mean moisture value of non-phreatophyte species, 9% of vegetation plots are considered GDV and 33% likely GDV. 80% of all GDV derived from classification occur in hydrostratigraphic units (HSU) that are characterized by surficial groundwater circulation and low permeability. The overall accuracy of classifying likelihoods is 62.7%. For 14.6% of the plots, non-GDVs were classified as GDVs (false positives), and only one GDV plot has been classified falsely as non-GDV (false negative). Local results on GDV locations can be overlayed with aquifer use or aquifer reaction to climate change in order to identify GDV under threat and implement sustainable managements of groundwater resources.

Hydrogeochemical and isotopic characterization of the Gioia Tauro coastal Plain (Calabria - southern Italy): A multidisciplinary approach for a focused management of vulnerable strategic systems

This work pursues the hydro-geochemical and isotopic characterization of the complex groundwater system of the Gioia Tauro Plain, one of the most important industrialized and agricultural coastal areas of southern Italy. The anthropic pressure exposes the water resources at risk of depletion and quality degradation making the plain groundwater a system of high scientific and social interest.The plain is characterized by a shallow aquifer, mostly recharged by local rains and a deep aquifer apparently less influenced by local precipitation. Both aquifers are mainly Ca-HCO3 waters except for localized sectors where Na-HCO3, Na-Cl and Ca-SO4 waters are present. In deep aquifer, both prolonged interaction with sedimentary rocks, mainly deriving from the erosion of crystalline rocks, and direct cation exchange represent the primary factors controlling the formation of Na-HCO3 waters. Mixing processes between these waters and either connate brine and/or deep thermal waters contribute to the formation of isolated high salinity Na-Cl-rich waters. In shallow aquifer, inputs of N-rich sewage and agriculture-related contaminants, and SOx emissions in proximity of the harbor are responsible of the increasing nitrate and sulphate concentrations, respectively. The Cl/Br and NO3/Cl ratios highlight contamination mainly linked to agricultural activities and contribution of wastewater.Along the northern boundary, the warmest groundwater (Na-Cl[SO4]) were found close to a bend of the main strike-slip fault system, locally favouring the rising of B- and Li-rich deep waters, testifying the influence of geological-structural features on deep water circulation.Despite the high-water demand, a direct marine intrusion is localized in a very restricted area, where we observed an incipient groundwater-seawater mixing (seawater contribution ≤7 %). The qualitative and quantitative conditions of the shallow aquifer still have acceptable levels because of the relatively high recharge inflow. A reliable hydrogeochemical conceptual model, able to explain the compositional variability of the studied waters, is proposed.

Rural revival? The rise in internal migration to rural areas during the COVID-19 pandemic. Who moved and Where?

During the outbreak of the COVID-19 pandemic, anecdotal evidence of a “rural revival” emerged mirroring the “urban exodus” hypothesis. Currently, we know that internal migration to rural areas increased in some countries during 2020, although not with the intensity speculated by the media. However, little is known about the attributes of rural areas attracting migrants, demographic composition of migration inflows, and if counterurbanisation movements persisted over 2021. Drawing on administrative population register data, we analysed the main types of rural areas pulling internal migrants in Spain and their demographic characteristics, namely age, sex and place of birth during 2020 and 2021, using the period 2016–2019 as a benchmark. Our results show that in-migration increased in rural areas close to cities and with high prevalence of second homes during 2020, while out-migration declined. Exceptionally high inflows persisted over 2021, but outflows converged to figures observed prior to the pandemic. Inflows to rural areas comprised internal migrants across a wide age spectrum, from young adults and families to retired individuals. These flows also comprised the foreign-born, particularly populations of a wide age range from Latin American countries.

Effect of the leading-edge protuberances on the aeroacoustic and aerodynamic performances of the wind turbine airfoil

Based on the restraining effect of the leading-edge protuberances (LEPs) on flow separation, this work focuses analyzing the aeroacoustic and aerodynamic performances for the wind turbine airfoil with LEPs near the outboard region of the blades, by using the experimental testing and numerical calculation methods. The associated flow patterns for the aeroacoustic and aerodynamic performances are revealed within the pre-stall and post-stall regions. The shedding of the separation vortices enhances the instability of the laminar boundary layer, generating the aerodynamic noise from the wind turbine airfoil. The LEPs suppress the generation of the tonal noise in pre-stall region by changing the distribution and reducing the intensity of the trailing edge shedding vortices. Moreover, LEPs can improve the aerodynamic performance of the wind turbine airfoil greatly by inhibiting the flow separation at a high inflow angle of attack. As a flow control method for the wind turbine blades, LEPs will help to improve the aeroacoustic performance of the blades under normal inflow wind conditions, and the aerodynamic performance under extreme wind situations where the inflow wind changes on a large scale frequently.

Impact of Fe2+ and Shear Stress on the Development and Mesoscopic Structure of Biofilms-A Bacillus subtilis Case Study.

Bivalent cations are known to affect the structural and mechanical properties of biofilms. In order to reveal the impact of Fe2+ ions within the cultivation medium on biofilm development, structure and stability, Bacillus subtilis biofilms were cultivated in mini-fluidic flow cells. Two different Fe2+ inflow concentrations (0.25 and 2.5 mg/L, respectively) and wall shear stress levels (0.05 and 0.27 Pa, respectively) were tested. Mesoscopic biofilm structure was determined daily in situ and non-invasively by means of optical coherence tomography. A set of ten structural parameters was used to quantify biofilm structure, its development and change. The study focused on characterizing biofilm structure and development at the mesoscale (mm-range). Therefore, biofilm replicates (n = 10) were cultivated and analyzed. Three hypotheses were defined in order to estimate the effect of Fe2+ inflow concentration and/or wall shear stress on biofilm development and structure, respectively. It was not the intention to investigate and describe the underlying mechanisms of iron incorporation as this would require a different set of tools applied at microscopic levels as well as the use of, i.e., omic approaches. Fe2+ addition influenced biofilm development (e.g., biofilm accumulation) and structure markedly. Experiments revealed the accumulation of FeO(OH) within the biofilm matrix and a positive correlation of Fe2+ inflow concentration and biofilm accumulation. In more detail, independent of the wall shear stress applied during cultivation, biofilms grew approximately four times thicker at 2.5 mg Fe2+/L (44.8 µmol/L; high inflow concentration) compared to the low Fe2+ inflow concentration of 0.25 mg Fe2+/L (4.48 µmol/L). This finding was statistically verified (Scheirer-Ray-Hare test, ANOVA) and hints at a higher stability of Bacillus subtilis biofilms (e.g., elevated cohesive and adhesive strength) when grown at elevated Fe2+ inflow concentrations.

Dynamization Analysis of Capital Inflow, Credit Allocation, and Banking Performance using Panel Vector Autoregressive

The direction of globalization and the integration of the financial system continue to increase, in line with the increasing capital flows, which is the focus of discussion in this research. This study applies panel data analysis to analyze banking behavior in order to improve its performance. The analysis uses panel data from 1991 to 2020 in 39 countries. Return on Equity (ROE) as a measure of the success of banking operations is determined by various interrelated factors. One of the variables closely related to banking performance is the share of non-financial business loans, the share of capital inflows entering the banking sector, and the share of capital inflows entering the non-bank sector. Economic variables that support good banking performance are GDP growth, bank concentration, inflation, leverage, and bank efficiency. This article applies a Panel Vector Autoregressive to capture the dynamization, and heterogeneity. The most exciting results were obtained by dividing the sample into subgroups, which helped the researcher understand each regime's different roles and transmissions. The changes in capital inflows to the non-bank sector will significantly reduce ROE and increase leverage for the next five periods. The results of the study imply that nowadays, bank managers should be aware while the changes in capital inflows change very quickly. Bank managers in countries with high capital inflows must always be aware of changes in capital inflows to the non-bank sector—steps to bank management by diversifying sources of funds efficiently from other parties in the transmission of credit channel.

Research on a Spontaneous Combustion Prevention System in Deep Mine: A Case Study of Dongtan Coal Mine

ABSTRACT Due to the influence of high ground stress, high ground temperature, high water inflow and other problems in deep mines, coal spontaneous combustion (CSC) is seriously harmful. This paper studied the variation law of three kinds of indicator gases in the process of coal heating in deep mines, and established a multi-parameter gas indicator prediction system for CSC. Secondly, in view of the shortcomings of the negative pressure bundle tube. A positive pressure beam tube monitoring system for early warning of CSC was developed, the accuracy of sampling data was verified on site, and the high temperature area in the well was further identified by isotope radon measurement. Combined with the positive pressure beam tube monitoring system, to realize the joint detection of uphole and downhole. Finally, according to the detection results of the fire area, the fire prevention methods for small space fire area, multi-coal seam and multi-source air leakage complex fire area and large-area concealed fire area are determined. The above-mentioned CSC early warning and prevention system was applied in Dongtan (DT) Coal Mine, and a good fire prevention effect was achieved. In this paper, the CSC prevention and extinguishing system established has important significance in the prevention and control of mine fires.

Phytoplankton biomass and community composition in three Texas estuaries differing in freshwater inflow regime

Because many estuaries worldwide are experiencing large-scale alterations in freshwater inflows due to climatic and human influences on watersheds, it is critical to understand ecosystem-level responses to freshwater inflow conditions and variability. This study compared environmental conditions and phytoplankton biomass/community composition among three Texas estuaries with differing freshwater inflow regimes to understand the impacts of freshwater inflow magnitude on phytoplankton communities. It was hypothesized that: 1) nutrient concentrations and phytoplankton biomass would be highest in San Antonio Bay (SA), the high inflow estuary and lower in Nueces-Corpus Christi Bay (NC) and Baffin Bay (BB) due to lower average inflows, and 2) the phytoplankton community would be dominated by large and/or fast-growing taxa in SA, with a greater fraction of small and/or slow-growing taxa in NC and BB. Highest inorganic nutrient concentrations were generally observed in SA, while high organic nutrient concentrations were found in BB. Chlorophyll a was relatively high in both SA and BB (mean 16.9–18.5 μg L−1) while phytoplankton biovolume was highest in BB. Despite distinct freshwater inflow, salinity and nutrient regimes, differences in phytoplankton community composition were less pronounced. Nano- or microplankton were the dominant size class of phytoplankton in each system, and diatoms were the dominant functional group, accounting for 27–49% of total biovolume on average. There were indications that the phytoplankton community was more diverse in SA, especially following inflow events, providing evidence that inflow may act as a disturbance that leads to greater phytoplankton diversity. Results from this study also showed that while freshwater inflow is important for nutrient delivery, low inflow estuaries such as BB are still susceptible to effects of eutrophication due to long residence times and nutrient retention/recycling. Overall, the differing responses of each of these ecosystems to freshwater inflow highlight the importance of system-specific management plans and consistent monitoring programs in coastal estuaries.

Effect of 4-day Online Breath Meditation Workshop on Ballistocardiography-based Sleep and Cardiac Health Assessments among Medical Professionals of a Tertiary Care Hospital in North India during COVID-19.

Medical professionals (MPs) are facing stress, sleep deprivation, and burnout due to pandemic-related high patient inflow and consistent work shifts. Yoga and meditation are feasible, cost-effective, evidence-based, and well-accepted tools having multifold mental and physical health benefits. In this ongoing open-label single-arm trial, we assessed changes in sleep, heart rate variability (HRV), and vitals before and after a 4-day online breath meditation workshop (OBMW) among 41 MPs at a tertiary care hospital in northern India during COVID-19 pandemic. Outcomes were assessed at baseline and after the 4-day workshop using a ballistocardiography-based contactless health monitoring device. The workshop was conducted online. Two participants were excluded due to a lack of adherence. A highly significant increase was seen in total sleep duration (p = 0.000) and duration of deep sleep (p = 0.001), rapid eye movement (REM) sleep (p = 0.000), and light sleep (p = 0.032). HRV outcomes of the standard deviation of normal-to-normal R-R intervals (SDNN) and root mean square of successive differences between adjacent normal heartbeat (RMSSD) also improved significantly (p = 0.000) while heart rate reduced significantly (p = 0.001). No significant change was observed in breath rate, total time awake, or in the low-frequency by high-frequency (LF/HF) spectrum of HRV. Four days of OBMW improved sleep and HRV among MPs, strengthening the fact that yoga and meditation can help induce psychophysical relaxation and prove to be an effective tool to combat stress and sleep deprivation. As the stakeholders in patient care, that is, MPs are healthy, it will further improve patient care and reduce the chance of medical errors.

HYDROLOGICAL PREDICTION FOR MAPPING THE POTENCY OF BREAK IN THE SAGULING DAM, WEST JAVA PROVINCE, INDONESIA

Dams are structures built across bodies of water to hold the water back. They offer various economic, environmental, and social benefits, including large-scale water storage, hydroelectric power generation, tourism, and recreation. However, in addition to offering benefits, dams are also associated with certain risks. One of the biggest risks is the possibility of a dam breaking, which may occur if the discharge inflow is overly high at the point it enters the reservoir. A very high discharge inflow can result in a probable maximum flood (PMF) discharge. This study investigates the potential of hydrological analysis with regard to mapping the dam break potency of the Saguling Dam in Indonesia. The reservoir system on the Citarum River consists of three reservoirs, namely Juanda (Jatiluhur), Cirata, and Saguling. Together, they comprise a cascade reservoir system. The Saguling Dam is located in the upstream, the Cirata Dam is in the middle stream, and the Juanda Dam is under the Cirata Dam. This study focuses on the Saguling and Cirata Dams. It analyzes the PMF using the Nakayasu, ITB-1, Gama-2, and Snyder methods. Moreover, the rainfall analysis involves the Thiessen polygon and the frequency distribution of the Gumbel, Log Pearson-III, and Log Normal, while the hourly rainfall is analyzed using the PSA-7 currently being investigated in Indonesia. The intensity of the rainfall in the catchment area of a dam is directly related to the level of the discharge inflow that enters the reservoir. The Saguling Dam faces a similar risk, which explains the need to conduct a comprehensive hydrological analysis to assess and map one of the key risk factors for the dam breaking.

Effects of inflow conditions on low mass-damping cylinder subjected to vortex-induced vibrations

This work analyses the effects of the inflow conditions on the bifurcations characteristics of a two-degree-of-freedom low mass-damping cylinder undergoing vortex-induced vibrations. A two-dimensional RANS model was implemented to simulate the fluid–structure interaction problem. The cylinder response was analysed under different inflow conditions and systematic decrements of the inflow acceleration. The results showed a bifurcated response throughout the upper branch, dependent on the inflow conditions. A low-amplitude state was observed at high inflow accelerations, whereas a high-amplitude state was reached when the inflow acceleration decreased below a certain threshold. A proper selection of the inflow conditions led to a significant increment of the minimum inflow acceleration required to trigger the upper branch, reducing up to 60% of the computational time per simulation. The bifurcated response was divided based on its temporal stability, where the cylinder transitioned from a high- to a low-amplitude state after several high-amplitude oscillations. Unstable responses were associated with multi-frequency fluid forces that interfere with the fluid–cylinder energy transfer, precipitating a state transition. A systematic analysis of the unstable region showed that slight differences in the initial inflow conditions and the inherent simplifications of the tested two-dimensional RANS model significantly impacted the cylinder response stability.

A contextual study of employee turnover intention in Vietnam F&B service sector: an integrative perspective

PurposePrevious studies on employee turnover did not explore the contextual differences of emerging markets such as Vietnam. As Vietnam is a fast-growing new tiger economy with a high inflow of foreign direct investment, contextual analysis needs to be conducted to handle rising HR issues in the region. The current study aims to analyze paths to employee turnover intention through an integrated model covering factors on individual, team, and organizational levels to understand the contextual difference in the Vietnam F&B service industry.Design/methodology/approachA mixed method was used based on quantitative and qualitative data from three organizations. For the quantitative analysis, a path model was developed and analyzed by SEM-PLS (Smart PLS) based on a sample size of 354. For the qualitative analysis, 32 semi-structured interviews were conducted to explore the contextual understanding in the regional context.FindingsAlthough the current study confirms that the paths among the three levels show the turnover factors developed in the previous study still applicable to the Vietnam context, the strengths and relationships among the team and individual levels imply that the Vietnamese context created a unique HRM environment forming different paths to reach employee turnover decisions.Originality/valueThe findings contributed to the literature on employee turnover by developing an integrated model of employee turnover encompassing the three levels, suggesting the different local contexts formed unique paths to employee turnover decisions.

Effects of changing environmental conditions on plastic ingestion and feeding ecology of a benthopelagic fish (Gadus morhua) in the Southwest Baltic Sea

This study documents how the abundance of microplastics (<5 mm) in the Atlantic cod, Gadus morhua, relates to the changes of the fish diet during years with contrasting levels of anoxia for example following years of low or high major Baltic inflows (MBI). A MultiNet Maxi trawl and CTD were deployed annually to collect microplastic samples alongside oxygen, temperature, and salinity conditions. Microplastics were homogenously distributed both within the water column and across years. Gadus morhua diet shifted from dominantly benthic invertebrates (61 %) under oxygenated conditions to dominantly Sprattus sprattus (81 %) under anoxic conditions. The proportion of G. morhua with microplastics in their digestive tract increased when they fed on pelagic fish (38 %) versus on benthic invertebrates (15 %). The proportion of S. sprattus which ingested microplastics (~18 %) did not vary. As anoxia at depth is expected to increase due to climate change, microplastic ingestion by G. morhua will potentially increase.

Study on fuel equivalence ratio range for supersonic premixed combustion mode to establish in a scramjet

With the tendency of high-speed flight and economic cruise, combustion mode in a scramjet engine will transfer from diffusion combustion mode to premixed combustion mode because of the decrease of Damköhler Number in combustor. In order to study the fuel equivalence ratio conditions for the establishment of premixed combustion mode and corresponding combustion mechanism, series of direct-connected experiments with gaseous ethylene as fuel were conducted. The total temperature of Mach 2.0 incoming flow ranged from 1200 K to 1700 K. Wall pressure of the combustor was collected to analyze related combustion mode and planar laser induced fluorescence (PLIF) was adopted to research combustion mechanism of corresponding combustion mode. Results showed that with the increment of fuel equivalence ratio ER, combustion mode transited from premixed combustion mode to partially premixed combustion mode and finally diffusion combustion mode. Bilateral injection scheme was more advantageous for premixed combustion to establish due to better fuel/air mixing and further downstream reaction position originating from diluted fuel in height position and corresponding low flame speed. Besides, total temperature of inflow had effect on the combustion characteristics in different aspects. On one hand, higher inflow total temperature brought lower lean fuel blow-off ER limit. On the other hand, the stabilization equivalence ratio range of premixed combustion mode would widen with the increment of inflow total temperature in the variation of 1200 K–1700 K which could be attributed to the coupling result of inflow temperature (affecting flame speed) and inflow velocity, indicating inevitability of appearance of premixed combustion mode in high-speed economic cruise with high inflow total temperature.

Reconceptualising flood risk assessment by incorporating sediment supply

Sediments seriously increase flood risk. The lack of sediment data, as well as uncertainty in sediment yield and transport modeling, hampers the incorporation of sediment into flood risk assessment/early-warning systems. In this study, we targeted a 10 km reach that experienced a flash flood with high sediment inflows in 2019 and simulated sediment impacts on flood propagation and flood risk using a 1D hydraulic model. Two sediment inflow types were considered: sudden inflow from a debris flow and constant inflow from upstream. For the former type, different inflow times before, during and after the peak discharge were tested; for the latter type, different sediment concentrations and medium grain sizes were tested in the scenario design. Our results showed that when sediments inflowed into the reach in a short time, they greatly increased the water level by up to 3.7 m in the reach near the inflow point (i.e., 500–700 m upstream and downstream of the point). When sediments constantly inflowed from upstream, they influenced the water level of the whole reach but raised the water level by up to 1.2 m in the cross-sections, which showed strong bed aggradation. Sudden sediment inflow influenced the reach near the inflow point and might increase its flood risk to the highest level, whenever it occurred before, during or after the peak discharge. Constant sediment inflow did not affect the flood risk of the peak discharge much but increased the risk afterwards when the sediment concentration was higher than 40 kg m−3. Cross-sections showing increased flood risk were characterized by decreasing bed slopes or increasing widths. In view of the impacts of different sediment inflow types on flood risk, we developed a method to identify potential sediment risk. Together with current risk assessment by water flow, we proposed a framework to incorporate sediment into flood risk assessment.