Erosion Issues Research Articles

Spatiotemporal distribution of global wind erosion over the past four decades

Abstract Wind erosion is a critical environmental issue that degrades land and air quality, affecting global ecosystems, agriculture, and human health. Yet, on the global scale, the long-term spatial variability and controlling factors of wind erosion remain highly uncertain. Here, we develop a high-resolution spatiotemporal dataset of global wind erosion from 1980 to 2020 using the Revised Wind Erosion Equation model, integrated with comprehensive meteorological, terrestrial ecology, and soil datasets. Our analysis indicates that wind erosion annually impacted 359 ± 25 petagrams of soils worldwide during this period. Approximately 70% of this erosion occurred in just ten countries, predominantly in Africa and the Middle East. Due to higher erosion intensities, pasturelands, accounting for 28% of all non-barren land use types, disproportionately contributed to 70% of the erosion in these areas. Furthermore, our analysis highlights an upward trend in global wind erosion over the past four decades, with affected areas expanding worldwide. Although our study reinforces that changing wind speeds and a drier climate are central factors impacting global wind erosion, we find that increasing erosion intensities in pasturelands may also exacerbate erosion in North Africa, South America, and East Asia. This has broad implications for soil erosion issues that impact food productivity, human health, and ecosystem stability. This research provides insights for developing wind erosion warnings and targeted mitigation strategies, supporting global efforts to combat environmental degradation and promote sustainable development.

Cathode-less RF plasma thruster design and optimisation for an atmosphere-breathing electric propulsion (ABEP) system

Atmosphere-breathing electric propulsion (ABEP) is a concept that ingests residual atmospheric gases as a source of propellant for an electric thruster, removing the need for onboard propellant storage. This would enable continuous low-thrust drag compensation, extending the lifetime of spacecraft in Very-Low Earth Orbit (VLEO); <250 km. VLEO is an appealing region for spacecraft operations, enabling new remote sensing missions with improved radiometric performance and spatial resolution, whilst reducing size, mass and power requirements, as well as mission cost. A preliminary design review and optimisation is therefore conducted for an ABEP system that uses the cathode-less radio frequency (RF) plasma thruster from Technology for Innovation & Propulsion (T4i) S.p.A. This removes the issue of thruster erosion by means of magnetic confinement and offers reduced susceptibility to varying atmospheric composition. A semi-empirical oxygen-nitrogen global source model (GSM) has been developed which considers the volume-averaged flux, momentum, and energy balance of the RF discharge. This includes a detailed chemistry model for the complex electron-molecular reactions and energy-loss channels of air plasma in the ionisation chamber. The GSM is coupled to an analytical model of flux balance for an air intake, verified by Direct Simulation Monte-Carlo (DSMC) simulation, to consider its design for maximum collection efficiency. This is then utilised in a robust multi-objective optimisation of the ABEP system, accounting also for spacecraft aerodynamics and power requirements.

Tuning the sulfide interface of MnCo2O4-based nanostructures enables efficient water/seawater electrolysis

Hydrogen generation through water electrolysis is greatly dependent on the development of energy and time-efficient techniques to construct stable and active electrocatalysts for oxygen evolution reaction (OER). Currently, major research focuses on producing hydrogen through direct seawater electrolysis instead of fresh water to build a sustainable society. However, competitive reactions such as chlorine evolution reaction (CIER) beyond OER and electrode erosion issues make seawater electrolysis more difficult. Here, we report an interfacial engineering strategy that constructs a MnCo2O4@CoS hybrid structure by sulfurization of the spinal MnCo2O4 nanowires. The hybrid structure demonstrates an excellent OER performance in electrolytes containing alkaline and saltwater. Specifically, the prepared catalyst needs overpotentials of 205 mV and 225 mV to deliver a current density of 10 mA cm−2 in 1 M KOH and alkaline seawater when used as OER electrocatalysts. This should be noted that the CoS layer on the surface of MnCo2O4 nanowires not only acts as a Cl‾ protective layer to impede electrode erosion and CIER but also provides metallic ions with a higher valence state to enhance the intrinsic catalytic activity of water oxidization. Thus, this type of electrocatalyst could represent a favorable choice, carrying substantial implications for hydrogen-based economies and environmental enhancement.

Development of Water Repellent Polish for the Pointing and Finishing on NBRRI Earth Block Walls

Assessment of the challenges facing the adoption and promotion of NBRRI CSEBs reviewed the issues of instability or erosion of the brick wall surfaces, a case study reveals that it is a common problem to all walls made of this block within different zones of the country. The quest to proffer sustainable solution to these challenges necessitated this research work. The study aimed at producing a locally sourced water repellent polish for painting and finishing on NBRRI earth block walls. A substance (slurry) that can resist moisture penetration into adobe walls through the surfaces. The materials used were sourced from the rainforest zone of the country, investigated and tried with different mix ration depending on the Oxide composition in phases. The first phase featured the following materials and equipment; limestone, crab soil, periwinkle shell, Termite mould, natural clay, Hydrated lime (Ca (OH)2, Soluble Rubber (Top Bond) and Distilled water for mixing. Equipment includes; Weighing balance of 0.1g accuracy, sieve no 2020 (75pm) stirring rod, brushes and spray. In this phase soluble rubber was tried differently with the materials in various oxide composition applied on the existing CSEB walling unit, from observation some performed well while others performed moderately. The second and the third phase of the trial employed limestone and hydrated lime (Ca (OH)2 as the main stabilizer to activate reaction between the combination of any of the samples that contained high silica and a certain percentage of aluminium oxide (Al2CO3) x H2O(c) to produce an effective result as the Ca (H2O(s)) react in the presence of air to give Ca2SiO3(s) a solid that is stable in water, and applied on CSEB wall surfaces for observation across wet and dry Season.

SEDIMENTATION IN HYDROELECTRIC POWER TURBINES

The primary cause of erosive wear and energy loss is friction, and reportedly, one-third of the world’s energy resources go to overcome friction by several methods. The presence of deposits in water is a common problem in mountainous regions and some Ukrainian hydroelectric power stations. Hydro turbines face serious issues related to erosion from deposits during operation. Erosive wear occurs due to the impact of solid particles against a solid surface. The current environment contains particles whose velocity is sufficient to damage metal surfaces. Various researchers have conducted numerous studies to minimise the effect of deposit erosion in multiple locations of Francis turbine components (FT). For this purpose, they performed field investigations, experimental measurements, empirical modelling, computational fluid dynamics (CFD) work, and other methods. Various empirical models have been used to describe erosive wear in terms of material and fluid properties. They established that, for ductile materials, maximum erosion occurs at an impact angle of 30°, whereas for brittle materials, it occurs in the range of 80–90°. In the literature, various experimental methods are available to quantitatively assess slurry erosion, such as the rotating disk apparatus (RDA), slurry tank testing, jet erosion testing, and rotating drum testing. Due to manufacturing technologies used in mechanical processing processes, the exposed surface has a certain absolute roughness that increases during machine operation due to abrasion or erosion. Therefore, surface texture leads to increased energy efficiency losses during operation. Technological advancements have facilitated the widespread use of computational tools to address deposit erosion issues. In recent decades, numerical methodology has been a widely used and effective tool, yielding tangible and reliable results. This study examines potential methods for detecting and reducing deposits. This type of erosion depends on flow characteristics, surface properties, and properties of the eroding material. The article provides comprehensive information on sedimentation (deposits) causing wear in hydraulic turbines. Keywords: hydroelectric turbine, sedimentation erosion, computational fluid dynamics, fluid-structure interaction.

칼 사우어(Carl O. Sauer)의 문화·역사지리학에 투영된 환경관

Despite Sauer set out his coursework in 1909 in the midst of Davisian physiography and environmentalism, Salisbury at Chicago assisted him to avoid the causative man-nature relation by laying emphasis on field observations. Having witnessed the widespread soil exhaustion in Illinois and Missouri, Sauer now at Ann Arbor had to redress economic and ecological problems from the deforestration of white pines on the Great Lakes. Advising on the issues of land utilization and soil erosion for the New Deal Government, Sauer in Berlekey shaped up the landscape morphology in which culture was conceived as an agent, natural landscape a medium and cultural landscape an outcome. The intellectual encounter with Boasian anthropology resulted in cultural and historical geography or culture history of seeking out the origin, diffusion and transformation of culture and cultural landscape, bearing the brunt of environmentalism. To be noted is that Sauer resurrected Marsh’s Man and Nature by organizing the 1955 international symposium on ‘Man’s Role in Changing the Face of the Earth’. Sauer’s environmental ethics urges us to do our moral and ecological duties for the coming generation.

Effects of structural configuration on perforation/spalling damage and secondary fragment velocity of reinforced concrete slabs subjected to close-in explosion

Reinforced concrete (RC) slabs are vulnerable to localized damage from close-in TNT explosions, suffering perforation and extensive spalling damages that generate high-velocity secondary fragments posing severe risks to nearby facilities and personnel. Current numerical methods such as the Finite Element Method (FEM) face challenges in accurately predicting fragmentation due to mesh distortion caused by large deformations and discontinuities, underscoring the need for enhanced modelling techniques. As a result, although numerous studies have numerically investigated how structural configurations influence RC slab damage under blast loads, the issue of mesh distortion and element erosion in FEM has led to the inability in reliably predicting the associated threats from high-velocity fragments. This study numerically investigates the influences of structural configuration (e.g., concrete strength, reinforcement ratio and layout, dimensions of slabs, and concrete cover depth) on the perforation/spalling area and fragment ejecting velocity of one-way RC slabs subjected to close-in explosions through an ALE-FEM-SPH numerical model, which has been demonstrated effective and reliable in the authors’ previous studies. The results indicate that concrete strength and slab thickness most significantly affect both the damage and fragment characteristics, while the slab's width-to-height ratio, reinforcement ratio, and layout, have less influence, particularly on fragment velocity. Empirical equations derived from extensive numerical data are provided to help engineers and security personnel quickly evaluate the blast effects on RC slabs. The accuracy and robustness of the proposed formulae, which can be straightforwardly used to predict blast fragments of reinforced concrete slabs, have been statistically evaluated and the proposed formulae demonstrate satisfactory precision, with less than 20 % error in estimating damage area, maximum fragment velocity, and total kinetic energy of fragments.

Development of Interpolyelectrolyte Complex Based on Chitosan and Carboxymethylcellulose for Stabilizing Sandy Soil and Stimulating Vegetation of Scots Pine (Pinus sylvestris L.).

The issue of water and wind erosion of soil remains critically important. Polymeric materials offer a promising solution to this problem. In this study, we prepared and applied an interpolyelectrolyte complex (IPEC) composed of the biopolymers chitosan and sodium carboxymethyl cellulose (Na-CMC) for the structuring of forest sandy soils and the enhancement of the pre-sowing treatment of Scots pine (Pinus sylvestris L.) seeds. A nonstoichiometric IPEC [Chitosan]:[Na-CMC] = [3:7] was synthesized, and its composition was determined using gravimetry, turbidimetry, and rheoviscosimetry methods. Soil surface treatment with IPEC involved the sequential application of a chitosan polycation (0.006% w/w) and Na-CMC polyanion (0.02% w/w) relative to the air-dry soil weight. The prepared IPEC increased soil moisture by 77%, extended water retention time by sixfold, doubled the content of agronomically valuable soil fractions > 0.25 mm, enhanced soil resistance to water erosion by 64% and wind erosion by 81%, and improved the mechanical strength of the soil-polymer crust by 17.5 times. Additionally, IPEC application resulted in slight increases in the content of humus, mobile potassium, mobile phosphorus, ammonium nitrogen, and mineral salts in the soil while maintaining soil solution pH stability and significantly increasing nitrate nitrogen levels. The novel application technologies of biopolymers and IPEC led to a 16-25% improvement in Scots pine seed germination and seedling growth metrics.

CFD Modelling of Swirling Mechanism to Reduce Erosion of Pipe Bend in Pneumatic Conveying System

Dry powders mixed with air transportation had bend erosion issues. CFD analysis by Shear-Stress Transport (SST) k-ɯ Model within Ansys was used to conduct a comprehensive numerical analysis of particle erosion within a 90° mild steel pipe bend in Pneumatic Conveying System. Part of the conveying pipe rotation achieved with the external motor swirling device was used to create swirling of particle before bend. Different-sized sand particles at different rpm were tested with and without a swirling device. Reduction in erosion rate of pipe bend carries significant implications, notably an extension of the system's operational lifespan. Reduction in erosion rate reports an impressive increase of 50% bend lifespan at higher RPM levels of the swirling device. The results underscore the effectiveness of this device in mitigating erosion, with significant implications for enhancing the longevity and reliability of bend life in piping systems of Pneumatic Conveying applications.

Design of a Stormwater Management System in Lady Irene Campus

This project aimed to design an efficient drainage system for Ndejje University's Lady Irene Campus, addressing issues of erosion and flooding exacerbated by recent construction projects. The goal was to create a hydraulic conveyance system that balances environmental protection with structural integrity and affordability. The project involved field reconnaissance, data collection, and analysis of the campus's landscape, soil types, and development trends to inform the design. Methodologically, the project used GPS surveying to create topographical maps and obtained rainfall data to size drainage facilities using the rational method. The peak runoff was calculated considering land use characteristics, while Manning’s formula was applied to design drainage channels and culverts. The design aimed to ensure high hydraulic capacity and prevent erosion with specific slope and material choices. An Environmental Impact Assessment was conducted, addressing noise, dust, water quality, waste management, and ecological impacts. Mitigation measures were recommended to minimize adverse effects during the construction and operation phases. Despite challenges such as limited access to surveying equipment and data, the project concluded with a comprehensive stormwater management plan. Recommendations include rehabilitating the university’s weather station and establishing a project database to support future planning and research. The project underscores the importance of integrating sustainable practices in urban development to safeguard environmental and infrastructural integrity.

Determination of annual energy production loss due to erosion on wind turbine blades

Increasing size of the modern wind turbines amplifies the issues of leading-edge erosion, especially on the outboard sections of the blades, impacting both their structural integrity and aerodynamic efficiency. Predicting and detection of the aerodynamic losses which occurs before a noticeable structural degradation on the blade can be crucial for operational predictive maintenance strategies to avoid significant loss production. This paper presents the results from the collaborative study between DTU and CENER in order to investigate the influence of leading-edge erosion on wind turbine aerodynamic performance. For this purpose, three distinct erosion scenarios are analyzed by means of computational fluid dynamics (CFD), both 2D and 3D, blade-element momentum theory (BEM) based solver (OpenFAST) and a Simplified Aerodynamic Loss Tool (SALT). The results from previous studies are used as an input for these tools, with outputs from each tool complementing and reinforcing one another. Furthermore, annual energy production (AEP) reductions due to leading-edge erosion across these tools are compared and validation of the SALT tool is presented. It is observed that the thrust and power losses from both CFD and OpenFAST exhibit comparable results and for a severe erosion case, spanning the last third of the blade, results in a 4.3 % reduction in the annual energy production.

Practical Calculation of Diaphragm Wall Deflection using Plaxis 3D Software

In this article, the mathematical models within the Plaxis 3D software were used to simulate and assess the deflection of diaphragm walls, comparing with data collected from a real project. This scientific and effective approach is crucial, as analyzing and simulating the excavation stages before constructing diaphragm walls for underground levels becomes essential for controlling wall displacement and preventing potential soil erosion issues in the surrounding deep excavation, which could have serious consequences for neighboring structures. The numerical modeling results demonstrate that the deflection of the diaphragm wall varies inversely with its thickness, but this variation is relatively small and quite compatible with the observed data

Monitoring and Forecasting of Coastal Erosion in the Context of Climate Change in Saint Louis (Senegal)

Owing to its unique physical and socio-economic characteristics, the Saint Louis region stands out as one of the most susceptible areas in Senegal to the adverse impacts of coastal erosion. The dynamics of erosion in this region are significantly influenced by the Langue de Barbarie (LB), a sand spit formed at the mouth of the Senegal River. Initially, in 2003, a 4 m wide artificial breach was strategically introduced to mitigate flooding; however, sediment dynamics expanded it to 6 km by 2020, thereby affecting the entire region. This study delves into the coastline change of the LB, specifically divided into three zones (LB-1, LB-2, and LB-3), spanning the period from 1994 to 2042. Leveraging Geographic Information System (GIS) and remote sensing techniques, our investigation reveals that, prior to the breach’s creation, the average dynamic coastline rates in zones LB-1, LB-2, and LB-3 were estimated at 4.4, 5.9, and 4.4 m/year, respectively. Subsequent to the breach, these rates shifted to −1.2, 8.4, and −2.7 m/year, with the most significant erosion observed alongshore of LB-3 at −6.6 m/year during the period 2002–2012. Projecting into 2032, LB-1 and LB-3 are anticipated to experience erosion rates of −11.5 and −26.8 m/year, respectively, while the LB-2 records an estimated accretion rate of 8.41 m/year. Eroded areas are expected to total 571,458 m2, while accumulated areas are expected to total 67,191 m2. By 2042, zones LB-1, LB-2, and LB-3 are expected to experience erosion rates of −23 and −53.6 m/year, resulting in the erosion of 1,021,963 m2 and the accumulation of 94,930 m2 with a dynamic rate of 168.2 m/year in zone LB-3. These results have significant implications for solving the urgent issue of coastal erosion in LB.

Article: Agenda Setting and Decision Making under the OECD/G20 IF and the WTO – Developing Countries and Reform

This article is the outcome of the call for papers on the topic ‘Democratic Legitimacy Of Decision Making Process in Tax’ The OECD/G20 IF and the WTO have increasingly been subject to calls for reform in recent years. Imbalanced power asymmetries in agenda setting and deficiencies in decision making mechanisms have contributed to the existential crisis under the WTO and to legitimacy challenges under the international tax rulemaking body by developing countries. This article examines similarities and differences in structural and procedural legal frameworks and political considerations that facilitate the rulemaking processes and compares the lessons that have been learned. The article finds that both institutions have [historically] fallen short of incorporate agenda items of interest aligned to national needs in developing countries, resulting in gradually declining perceptions of legitimacy and exclusionary processes dominated by closed groups of developed countries. As a result, developing countries under the WTO have used decision-making processes to ‘opt-out’ as an exercise of country preferences thereby resulting in gridlocks caused by the exclusionary nature of the agenda. The informal fluid structure of the OECD/G20 IF has facilitated critical global breakthroughs in Base Erosion and Profit Shifting (BEPS) related issues, its exigent nature, however, has conversely resulted in challenges. These have been charachterized by opaque arbitrary procedures on the acceptance and rejection of proposals creates input-legitimacy concerns; timelines that impinge on democratic consultative processes; and the absence of alternative approaches to ‘opt-out’, limiting policy options for developing countries. The article further finds that special and differential treatment (S&amp;amp;DT) provides developing countries with much needed policy discretion to address international trade and tax related issues of interest. This may potentially counteract agenda-setting and decision-making deficiencies in both institutions and offset pre-existing onerous commitments imposed by the single-undertaking principle and BEPS minimum standards. S&amp;amp;DT is not without its challenges and controversies, though deficiencies in the relevancy of measures, lack of enforceability, and disagreements over eligibility highlight current weaknesses. The article explores a number of reforms and proposals. Inclusive-Framework, WTO, agenda-setting, decision-making, rulemaking, S&amp;DT, preferential-treatment, developing, UN, consensus.

დროებითი სარწყავი ქსელის არხების გარეცხვა

Reduction of soil erosion is one of the main issues of modern engineering ecology. It should be noted that this problem is caused not only by natural factors, but also by peculiarities of some irrigation methods. The article considers the issue of erosion of earthen channels of temporary irrigation network under gravity irrigation. On the temporary irrigation network of three villages in Shida Kartli region of Georgia the amount of erosion was experimentally determined and its dependence on network parameters and soil conditions was established. As a result of this work, to reduce soil erosion (scouring), it is recommended to install canals with compacted crosssection.

Quantifying Soil Erosion in Drought-Impacted Central Odisha, India, through Geospatial Mapping with RUSLE

Soil degradation in Odisha poses a significant conservation concern for the local environment. The present research focused on a region in central Odisha State, India, affected by drought conditions. Several models have emerged to assess soil loss, with the Revised Universal Soil Loss Equation (RUSLE) standing out as the most suitable option. The erosion computation process entails utilizing the digital elevation model (DEM), Landsat-9 imagery, and soil data from several sources accessible in different forms and scales. The present analysis took into account various elements, namely, crop management factor (C), practice management factor (P), slope length factor (LS), steepness factor of the slope (S), and rainfall factor (R). Multiplying these factors yielded the average rate of soil erosion. Areas with a high slope length factor, such as those in Kandhamal, Kalahandi, and Nuapada, have a high erosion rate. The study reveals that 57% of the land in the study area experiences very low to moderate soil erosion at a rate of 2–10 tons per hectare per year, while 43% faces moderately to very severe erosion at a rate of 10–25 tons per hectare per year. Erosion hotspots, covering 32,205 square kilometers, are mainly identified in agricultural and forested hilly areas where slopes exceed 10°, such as those in Kandhamal, Kalahandi, and Nuapada, which have a high erosion rate. These districts are especially vulnerable to soil loss and resulting climate action (Sustainable Development Goals-13) because of frequent and severe rainfall, shifting agricultural practices, a thin surface soil covering, natural erosion, and barren hills. The research emphasizes the urgent need for implementing conservation and management measures to protect high-risk areas from further degradation. In conclusion, the study underscores the effectiveness of the RUSLE-GIS model in conducting quantitative and spatial assessments of soil erosion on a river watershed scale. The model is deemed crucial in formulating conservation strategies to address the identified erosion issues in the tropical highlands of the area.

Integrated Universal Soil Loss Equation (USLE) and Geospatial Approach to Assess Soil Erosion in Machhu Sub-watershed, Morbi, India

Abstract Soil erosion is a severe and rapidly rising issue in many parts of the world due to human activities such as farming practices, land excavation for development and deforestation. Moreover, it can negatively impact water availability, agricultural growth, and ultimately, countries’ long-term economy. A quantitative and consistent land degradation assessment is vital for proper planning of soil conservation activities in a catchment or watershed. The Universal Soil Loss Equation (USLE) model is applied in this study to address the issue of soil erosion in the Machhu-sub watershed (24769.63 ha), located in Saurashtra, India. The landscape feature of the study area includes basalt type rock and water body. In this USLE model study we have used input parameters such as rainfall erosivity (R), soil erosivity (K), cover management (C), slope length and steepness (LS), and conservation practice (P) integrated with Geographical Information System (GIS) to analyze and obtain the estimated annual soil loss. Results indicated that the overall soil loss in the study area can be classified into five categories: Very Low (0-1), Low (1-3), Low moderate (3-5), Moderate (5-10), and High ( &amp;gt;10 tons/ha/year). The finding includes the overall soil potential loss of the Machhu sub-watershed is 14.90 tons/ha/year. Furthermore, 60.86 % of the agricultural area is affected by soil erosion. Therefore, the necessary soil conservation methods can be planned in the Machu-sub watershed area based on the USLE analysis. These findings may assist researchers, scientists, and policymakers in building a concrete strategy for sustainable development of not only study area but other catchments also.

Hydrohelical ESP Gas Separator Increases Flow Range, Improves Reliability

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214723, “New High-Performance ESP Gas Separator,” by Barry Nicholson, SPE, and Scott R. Harryman, SPE, Oxy, and Donn J. Brown, SPE, Halliburton, et al. The paper has not been peer reviewed. _ The complete paper presents research, design, and field testing of a new type of mechanical gas separator for electrical submersible pump (ESP) systems that increases operating flow range and separation efficiency while decreasing erosion problems and improving reliability. The hydrohelical separator system has been proved effective in different types of wells. Background Several methods and techniques exist for avoiding gas in ESPs, including inverted shrouds, passive separators, mechanical gas separators, and tandem gas separators. Most share the limitations of limited flow capabilities and reduced performance at higher total flow rates. The many variables associated with complex two-phase flow behavior, internal and external pressure variations, separation methods, velocity and viscosity of fluids, effect of the pump bolted above, inherent erosion issues, and single vs. tandem designs add to the challenge of basic mechanical gas-separator operation. In 2016, a program was initiated that featured investment in both experienced personnel and advanced testing technology to unravel the aforementioned challenges and improve understanding of the operation of downhole mechanical gas separation. The team investigated innovative methods of testing and created a transparent testing system that allowed visual observation of individual internal flow regimes as well as component performance. Using a combination of high-speed photography, computational fluid dynamics validation, and specialized instrumentation, every component of a mechanical separator system was enhanced for higher flow capabilities, improved separation efficiency, and higher reliability for a variety of downhole conditions. The result was the development of a new type of mechanical gas separator for ESP use. Development Most gas separators ingest multiphase fluid into a separation chamber, separate the gas and liquid phases, eject the separated gas phase into the well annulus, and provide sufficient liquid phase fluid to the pump to enable efficient pumping. Existing designs vary, but they share separation methods that result in decreased efficiency at higher flow rates and low maximum flow rates compared with the pumps they feed. The hydrohelical gas separator is the first downhole, dynamic gas-separator design improvement in more than 30 years designed to address these deficiencies (Fig. 1). The design was aimed at the following main objectives: - Increase total fluid flow rate through the separator - Maximize efficiency of every internal and external component of the system - Reduce erosion characteristics common in traditional gas-separator designs - Improve reliability The design of the hydrohelical gas separator is based on a stationary helical vortex inducer and pump stages that enable movement of large quantities of fluid while remaining immune to gas locking. The stationary helical vortex inducer design enables increased efficiency and flow rate through the separator by reducing turbulence in remixing regions within the helical inducer and separation chamber.

A CMIP6 Multi-Model Analysis of the Impact of Climate Change on Severe Meteorological Droughts through Multiple Drought Indices—Case Study of Iran’s Metropolises

This study extensively explores the impact of climate change on meteorological droughts within metropolises in Iran. Focused on Tehran, Mashhad, Isfahan, Karaj, Shiraz, and Tabriz, this research employed CMIP6 climate models under varying climate change scenarios (SSPs) to forecast severe meteorological droughts spanning the period from 2025 to 2100. The investigation utilized a diverse set of drought indices (SPI, DI, PN, CZI, MCZI, RAI, and ZSI) to assess the drought severity in each city. This study is crucial as it addresses the pressing concerns of rapidly decreasing water levels in Iran’s dams, serious declines in underground aquifers, and the compounding issues of land subsidence and soil erosion due to excessive groundwater withdrawal in the face of severe droughts. This study culminated in the generation of box plots and heatmaps based on the results. These visual representations elucidated the distribution of the drought values under different indices and scenarios and provided a depiction of the probability of severe drought occurrences until the end of the century for each city. The resulting findings serve as invaluable tools, furnishing policymakers with informed insights to proactively manage and fortify metropolitan resilience against the evolving challenges posed by a changing climate.

Soil Erosion Characteristics in Tropical Island Watersheds Based on CSLE Model: Discussion of Driving Mechanisms

Previous research has primarily focused on soil erosion issues in arid and semi-arid regions, with a limited understanding of soil erosion mechanisms in tropical areas. Additionally, there is a lack of a holistic perspective to determine the spatial attribution of soil erosion. The conversion of tropical rainforests into economically driven plantations, like rubber and pulpwood, has resulted in distinct soil erosion characteristics in specific regions. To enhance our knowledge of soil erosion patterns and mechanisms in tropical regions, it is necessary to examine soil erosion in the three major watersheds of Hainan Island from 1991 to 2021, which encompass significant geographical features such as tropical island water sources and tropical rainforest national parks. The study employed the China Soil Loss Equation (CSLE) model, slope trend analysis, Pearson correlation analysis, land-use transfer matrix, and spatial attribution analysis to examine soil erosion under different scenarios. The research results indicate that scenarios driven by the combination of natural and human factors have the greatest impact on soil erosion changes in the entire study area. Co-driven increases affected 53.56% of the area, while co-driven decreases affected 21.74%. The 31-year soil erosion showed an overall increasing trend. Human factors were identified as the primary drivers of increased soil erosion in the Nandu River basin, while a combination of climate and anthropogenic factors influenced the decrease in soil erosion. In the Changhua River basin, climate and human activities contributed to the soil erosion increase, while human activities primarily caused the decrease in soil erosion. In the Wanquan River basin, climate intensified soil erosion, whereas human activities mitigated it. This study underscores the significant combined impact of human activities and natural factors on soil erosion in tropical regions. It emphasizes the importance of considering human-induced factors when implementing soil erosion control measures in tropical regions.