Pumping Facilities Research Articles

Investigation of operational settings, environmental conditions, and faults on the gas turbine performance

Abstract Gas turbine engines are complex mechanical marvels widely employed in diverse applications such as marine vessels, aircraft, power generation, and pumping facilities. However, their intricate nature renders them susceptible to numerous operational faults, significantly compromising their performance and leading to excessive emissions, consequently incurring stringent penalties from environmental regulatory bodies. Moreover, the deterioration of gas turbine performance is exacerbated by variations in working conditions based on operational settings and environmental conditions. Past studies have focused on certain working conditions that limit effectiveness in real-world applications where operational settings and environmental conditions vary during operations. The influence of these working conditions on the performance of gas turbines also needs to be assessed, as they can lead to different fault patterns resulting in unplanned maintenance, unnecessary maintenance costs, unsafe conditions and stringent penalties. This study uses the gas turbine simulation program to simulate a high-bypass turbofan engine inspired by Pratt & Whitney PW-4056, analysing the combined effects of operational settings and environmental conditions on engine performance while also incorporating simulations of common gas turbine faults like fouling and erosion in various locations and severities along the gas path. The model’s accuracy is confirmed by low mean absolute percentage errors of 0.004% of thrust at the cycle reference point and 0.15% and 0.28% at 2 km and 7 km altitudes, respectively, demonstrating the model’s robustness across varying operational scenarios. In conclusion, this research highlights the significant effects of operational settings and environmental factors on gas turbine performance, particularly impacting specific fuel consumption and thrust. The study reveals that operational settings and environmental factors significantly impact fuel consumption and thrust. Specifically, compressor fouling and low-pressure turbine erosion increase nitrogen oxide (NOx) emissions by 4.5% and 11.1%, while fouling of nozzle guide vanes and high-pressure turbine erosion raise unburned hydrocarbon by 10.0% and 20.2%, and carbon monoxide (CO) by 3.2% and 5.2%, respectively, compared to a healthy engine. These insights highlight the importance of component-specific degradation in influencing gas turbine performance and emissions.

Building a resilient North Jakarta: Integrating social preferences for effective adaptation and mitigation strategy in the climate change era

Abstract The northern part of Jakarta, Indonesia, has been grappling with recurring floods due to climate change, affecting residents’ lives and livelihoods. Sea level rise, land subsidence, and increased precipitation increase the risk of river flooding. While the government has implemented physical flood mitigation measures, these alone are insufficient due to climate uncertainty. This 2017 study assesses socio-cultural risks in northern Jakarta and community preferences for climate change adaptation strategies. The study was conducted in 2017 and the study’s insights remain relevant to contributed as one of the scientific basis for the statutory planning of Jakarta to build the social resilience. Employing qualitative approaches, it collected data at mezzo and micro levels. Findings show that households adopt various private and public mitigation-adaptation measures. Most prefer elevating household items to higher ground (62.9%), while 44% favor maintaining the local drainage system and improving pumping facilities. However, 62% resist relocating to vertical houses, fearing job loss or increased expenses. Only 13% express willingness to relocate voluntarily for more comfortable housing. This resistance stems from the apprehension that such relocation might negatively impact their overall welfare, either by jeopardizing their employment opportunities or by increasing their monthly expenditures.

Impact of Seismic Geohazards on water supply systems and pipeline performance: Insights from the 2023 Kahramanmaras Earthquakes

This study delves into the profound repercussions of geohazards on water supply systems, specifically in the aftermath of the Kahramanmaras earthquakes. The influence of these geohazards was far-reaching, impacting a vast geographical expanse affected by the seismic events. The primary focus of this investigation centers on the provinces of Adiyaman, Gaziantep, and Hatay, providing representative damage examples from the earthquake-affected areas. The study illustrates various types of pipe failures induced by geohazards such as fault displacements, landslides, and liquefaction. The analysis encompasses diverse cases of damage, starting from the water resources, progressing through issues at transmission lines, and extending to challenges faced by pumping and treatment facilities. Key aspects of damages and geohazards are presented, shedding light on the intricate dynamics of these interactions. It is crucial to note the scarcity of real cases in the existing literature, emphasizing the need for extensive site investigations and dedicated research endeavors to construct a comprehensive database of case histories in this domain. This study addresses this gap, contributing valuable insights into the tangible impacts of geohazards on water supply systems. By comprehending and effectively addressing the risks associated with geohazards, water supply organizations can fortify the safety and resilience of their infrastructure. The findings presented herein offer a foundation for informed decision-making and strategic planning, fostering a proactive approach to mitigate potential damages and enhance the overall robustness of water supply systems in regions prone to seismic events and associated geohazards.

IMPROVING APPROACHES TO DETERMINING THE LEVEL OF FILLING OF THE PIPE BODY WITH PUMPED PRODUCT

As of 2015, there were more than 200 permanent and variable gravity sections of crude oil and petroleum product pipelines in the pipeline system of PJSC Transneft, the natural monopoly for pipeline transportation of crude oil and petroleum products in the Russian Federation. The operation of gravity sections in oil pipelines in Russia is a very important safety and environmental issue, and Russian oil transportation companies are constantly working on improving approaches to monitor and control pipeline operation modes. When these sections occur, special attention is given to determining the geometric capacity of the pipeline section, as pumping is done in batches and commercial pumping product remains in the gravity section during periodic shutdowns. Due to the limited technical equipment of these sections and the likely illegal unrecorded product withdrawals in these pipeline sections, the most demanding approach is to determine the fill factor of the pipe body. The fill factor is influenced by many factors, including the presence of gas phase and water accumulations, correct geometry of the pipe body and other factors. Given the given initial data, it can be seen that the solution to the problem of determining the filling level of a stopped oil pipeline is reduced to the construction of a multifactor model. For accurate determination, in addition to the model, there is a need for relevant software, an algorithm for solving the problem ofcalculating the filling factor. Correspondingly, operating organisations need a system for accounting and control of the product filling level at these sections at the level of improvement of the state system for ensuring unity of measurements and metrological support of accounting for the long-distance pipeline transport of oil and oil products - a strategic resource, the revenues from the sale of which account for about 23 % of the budgetary system of the Russian Federation.The calculation created and proposed by the authors is divided into stages in which the initial data is sequentially collected, the voltages on the capacitors are calculated, the data is processed using the interpolation method, an image is constructed using the Newton-Gauss method, and the filling factor is calculated with various multiphase pumping products. The calculation is made based on voltage readings from sensors located orthogonally to the axis of the pipe body. Using the approximation method and the Newton-Gauss method, you can get rid of the «noise» and level the phase boundary. When tested and implemented at pipeline pumping facilities, it will be possible to clarify the existing dependences of the influence of gas phase friction on the fluid flow rate, and, therefore, evaluate the effect on the filling factor. This calculation can become a tool in the fight against illegal tappings.

Advancing Construction Efficiency through Geochemical Remediation: Limescale Management in Jet Grout-Driven Pumping Facilities

Advancing Construction Efficiency through Geochemical Remediation: Limescale Management in Jet Grout-Driven Pumping Facilities

The Use of Hose Reel Irrigation Machines and Energy Efficient Components in Irrigation

The energy consumed for irrigation is one of the most important inputs in crop production. Irrigation water is distributed within the parcel with minimum loss by using winged or gun systems together with a hose reel irrigation machine (HRIM). The increase in the amount of energy consumed for irrigation increases the cost of the unit product. To reduce the unit product cost, irrigation systems must be used with energy-efficiency units. Frequency converters (FC), pressure transmitters (PT), and programmable logic controllers (PLC) are among the components used to provide energy efficiency. A change in the amount of current drawn by the motors according to the changes in the required flow rate in the pumping facilities is possible by using FC, PT, and PLC. In addition, with more than one motor pump pair; it is necessary to use FC and PLC to be used by connecting in parallel, to operate with the principle of co-aging, and to make a soft start. Instantaneous pressure information is transmitted to PLC and FC via a PT to be installed on the collector in the discharge line in systems with parallel-connected pumps. In this way, the motor revolutions used to drive the pumps are changed via FC, in real-time according to the changes in the flow. Thus, pump-motor pairs are operated with the principle of "constant pressure variable flow" and energy savings are achieved.

Delta Smelt stress responses during fish salvage at the John E. Skinner Delta Fish Protective Facility, California

The John E. Skinner Delta Fish Protective Facility (Skinner Fish Facility) diverts entrained fish from the State Water Project’s pumping facilities in the southern Sacramento-San Joaquin Delta (the Delta) and transports them via tanker trucks away from the immediate influence of the export pumps. During this process, the fish are counted and released back into the Delta, generally known as fish salvage. Since fish are caught and released back into the Delta, this whole process involves various points that can be stressful to fish, such as the Delta Smelt (Hypomesus transpacificus), a state and federally listed species. To understand this process and improve fish facilities function, an investigation was conducted in 2005–2006, in which we evaluated sublethal stress associated with the terminal portion of the fish salvage process. This study included fish collection, handling, transportation, and release (CHTR) away from the export facilities. Physiological stress parameters for Delta Smelt were measured in the Skinner Fish Facility. We inserted wild and cultured adult Delta Smelt into the CHTR process and later sampled for plasma cortisol, glucose, and lactate, which typically respond to acute and cumulative stress in fish. To help identify the source of overall stress response, we partitioned CHTR into three test phases: collection and handling, trucking and release, and uninterrupted CHTR. Differences in the delayed stress response between the different phases of CHTR were evaluated. Delta Smelt experienced stress in all phases of the CHTR process and in experimental handling controls indicated by higher plasma cortisol concentrations compared to their pre-experiment levels. Wild Delta Smelt experienced higher levels of cortisol response and took longer to recover than did cultured Delta Smelt.

Mismatch problem of the model and topology of oil pumping facilities

The mismatch of the model and the topology of real objects is important in modeling technological processes, which is the purpose of this paper. The problem is considered when modeling hot oil pumping in the "Kasymov–Bolshoy Chagan" oil pipeline. In this problem, the topology of objects consists of the linear part of the pipeline and technological equipment (pumps and heating furnaces) of the stations. The accuracy of the simulation results is determined by the calculations of pressure and temperature in the oil pipeline. The pressure in the pipeline is created by pumps at the stations and is determined by the dependence of the pressure and efficiency of the pump on the oil flow rate. These characteristics change depending on the service life of the pump. The identification of the actual dependences of the pressure and efficiency of the pump on the oil flow rate was carried out by the regression analysis of experimental data. The pressure in the linear part is determined by the hydraulic resistance of the pipeline. The actual dependence of the hydraulic resistance coefficient on the Reynolds number and wall roughness was obtained by regression analysis of experimental data. The temperature in the oil pipeline is created at the stations by heating furnaces. The identification of the actual characteristics of the heating furnace was also found by regression analysis of the experimental data. The temperature distribution in the linear part is determined by the heat transfer of oil with the surrounding environment. An undefined parameter for calculating heat transfer is the soil thermal conductivity, which depends on the type of rock and the degree of soil moisture. The soil thermal conductivity is determined in such a way that at a given oil flow rate, oil temperatures at the beginning of the section and soil at the section, the calculated oil temperature at the end of the section has the smallest discrepancy with the actual one. Thus, the determination of the actual dependencies of the objects makes it possible to increase the accuracy of the results of hot pumping modeling and eliminates the mismatches of the model and the topology of the objects.

Optimization of environmental DNA analysis using pumped deep-sea water for the monitoring of fish biodiversity

Deep-sea ecosystems present difficulties in surveying and continuous monitoring of the biodiversity of deep-sea ecosystems because of the logistical constraints, high cost, and limited opportunities for sampling. Environmental DNA (eDNA) metabarcoding analysis provides a useful method for estimating the biodiversity in aquatic ecosystems but has rarely been applied to the study of deep-sea fish communities. In this study, we utilized pumped deep-sea water for the continuous monitoring of deep-sea fish communities by eDNA metabarcoding. In order to develop an optimum method for continuous monitoring of deep-sea fish biodiversity by eDNA metabarcoding, we determined the appropriate amount of pumped deep-sea water to be filtered and the practical number of filtered sample replicates required for biodiversity monitoring of deep-sea fish communities. Pumped deep-sea water samples were filtered in various volumes (5–53 L) at two sites (Akazawa: pumping depth 800 m, and Yaizu: pumping depth 400 m, Shizuoka, Japan) of deep-sea water pumping facilities. Based on the result of evaluations of filtration time, efficiency of PCR amplification, and number of detected fish reads, the filtration of 20 L of pumped deep-sea water from Akazawa and filtration of 10 L from Yaizu were demonstrated to be suitable filtration volumes for the present study. Fish biodiversity obtained by the eDNA metabarcoding analyses showed a clear difference between the Akazawa and Yaizu samples. We also evaluated the effect of the number of filter replicates on the species richness detected by eDNA metabarcoding from the pumped deep-sea water. At both sites, more than 10 sample replicates were required for the detection of commonly occurring fish species. Our optimized method using pumped deep-sea water and eDNA metabarcoding can be applied to eDNA-based continuous biodiversity monitoring of deep-sea fish to better understand the effects of climate change on deep-sea ecosystems.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ АВТОМАТИЧЕСКИХ УСТАНОВОК КОМПЕНСАЦИИ РЕАКТИВНОЙ МОЩНОСТИ В НЕФТЕПРОМЫСЛОВЫХ ЭЛЕКТРИЧЕСКИХ СЕТЯХ

The relevance One of the key directions of innovative development of the electric power industry until 2035 is the transition to digital active-adaptive networks with a distributed intelligent automation and control system. In this regard, in conditions of increasing demands for improving the quality of electricity and reducing losses in networks, it is necessary to improve the voltage and reactive power regulation system in electric networks, which should be based on the widespread use of modern means of regulating voltage and reactive power, as well as automatic control systems, including centralized ones. The main effect of reducing technical losses in electric networks, as shown by the energy survey of FGC UES JSC, the experience of foreign electric grid companies and the analysis of the modes of operation of the Unified National Electric Grid, can be obtained by optimizing the established modes of operation of the electric grid in terms of reactive power and voltage levels in automatic mode, provided that the condition of regulating devices is constantly monitored. The absence of a system for remote monitoring of the parameters of power factor correction devices in the power supply systems of enterprises leads to untimely detection and elimination of failures in the operation and operation of the network without power factor correction. Aim of research To analyze the energy parameters of the power supply system of oil production facilities, to identify deviations of voltage values and power factor from regulatory requirements. To investigate the effectiveness of the use of low-voltage automatic power factor correction units in the power supply system of an oil-producing enterprise. Research methods The study of scientific literature, field research at oil pumping facilities, energy surveys, computer modeling. In order to identify the technical and economic efficiency of the use of low-voltage automatic power factor correction units, pilot field tests were conducted in one of the oil and gas producing enterprises of the Tatneft PJSC. Results Energy surveys of in-field pumping facilities, oil treatment and reservoir pressure maintenance of Tatneft PJSC have shown that the value of reactive power in the networks of power supply systems of these enterprises significantly exceeds the standard. As a result of pilot field tests, it was revealed that the use of automatic power factor correction units in automatic mode ensures the stabilization of the power factor at the level of standard values, excluding under-compensation or overcompensation of reactive power, while reducing electricity consumption by an average of 2.4 %. The remote monitoring system allows you to monitor the operating mode and technical condition of all elements of the capacitor plant, timely perform maintenance of contactors to ensure the operability of the installation.

Comparative evaluation of two photovoltaic multi-pump parallel system configurations for optimal distribution of the generated power

The suitability of a strategy for distributing the power generated by a photovoltaic pumping system equipped with two equal pumps working in parallel is proven. This strategy aims to improve energy management and consists of feeding a single pump with all the power generated until it exceeds a threshold value from which the power distribution must be at 50% between the two pumps. This pumping method was compared with the operation mode usually applied in parallel PV pumping facilities (50% of the power always assigned to each pump). A system equipped with two 0.75 kW pumps was employed. The assessment of the facility’s performance under the two alternative working conditions and several pumping heads was conducted using simulation techniques. Both the pumped annual volume and the annual efficiency of the motor-pump group increased when the strategy was applied compared to operation with power distribution at 50%. This increase was greater the higher the head (6.21% at H = 18 m vs. 57.60% at H = 48 m for pumped annual volume and 6.42% at H = 18 m vs. 57.51% at H = 48 m for annual efficiency). The halving of the irradiance threshold and the improved efficiency (36.4% vs. 34.8%) may explain this increase.

Novel integrated system of LNG regasification / electricity generation based on a cascaded two-stage Rankine cycle, with ternary mixtures as working fluids and seawater as hot utility

This paper presents a novel compact system of liquefied natural gas (LNG) regasification/electricity generation, with a two-stage cascade Rankine cycle, using the ternary mixtures methane-ethylene-propane (CH4–C2H4–C3H8) and ethane-propane-butane (C2H6–C3H8–C4H10) in the first and second stages, respectively, with seawater as the hot utility and LNG as the heat sink. The system was simulated using the Aspen Plus® simulator, considering not only power generation subsystem with the recovery of the LNG cold energy, but also the conventional LNG pumping and boil-off gas (BOG) recovery facilities, as commonly implemented in a European standard LNG terminal – with natural gas send out specifications compliant with a high pressure transmission network. After optimization, the system achieves a thermal efficiency of 23.7% and an exergy efficiency of 79.18%. Performance was found to increase when compared to a conventional system with a simple Rankine cycle, with propane as working fluid, or a two-stage cascade Rankine cycle with ethane/propane as working fluids. The economic assessment also favours the novel system over the conventional systems. The improvement obtained comes from an adequate working fluid selection, instead of a highly complex design or from the availability of high-grade hot utilities.

Factors influencing breastfeeding practices in China: A meta-aggregation of qualitative studies.

The World Health Organization recommends that women exclusively breastfeed until their babies are 6 months old and continue to breastfeed while introducing complementary foods. A meta‐aggregation methodology was used to systematically review and synthesise the qualitative studies on factors influencing breastfeeding practices of healthy Chinese women in Greater China. English and Chinese databases were searched to identify peer‐reviewed qualitative studies (published 2008–2019). Relevant data were extracted, and key themes related to factors influencing breastfeeding practices were identified. Of 7587 articles identified, 22 qualitative studies met inclusion criteria for the review, 10 of which were published in Chinese. A total of 87 themes were extracted from all included studies and classified into 9 subcategories: government enactment of policies, implementation of policies in workplaces, social expectations, social support, medical and health services, services with Chinese characteristics, breastfeeding and pumping facilities, maternal perceptions of breastfeeding and self‐efficacy to breastfeed. The nine subcategories were then grouped into four categories. Potential effect associations among these influence factors of breastfeeding practices emerged from categories and subcategories. Family members' influence on breastfeeding motivation and self‐efficacy suggest a potential benefit of breastfeeding promotion interventions targeting the whole family. The role of primary care should be fully exploited in breastfeeding promotion, including both prenatal education and post‐partum visits. Standardising the training and qualifications of maternity matrons (yuesao) and folk breastfeeding specialists (cuirushi) can promote evidence‐based approaches to facilitating breastfeeding during the confinement period. Increased availability of breastfeeding and pumping facilities in the workplace would facilitate continuing breastfeeding after returning to work.

Optimal short-term water-energy dispatch for pumping stations with grid-connected photovoltaic self-generation

Increases in the energy costs of irrigation water pumping facilities puts the economic sustainability of recent investments in the modernization of farms at risk. To address this problem, it is essential to apply renewable technologies for the production of electricity, and photovoltaic energy is particularly attractive due to its lower cost and recent technological advances. The aim of this research is to develop a mathematical techno-economic dispatch model that optimizes the hourly schedule of pumping equipment subject to electrical and hydraulic constraints to minimize the weekly operating costs of a real pumping station. The resulting model is formulated as a mixed-integer nonlinear programming problem that determines the optimal hourly combination of pumping equipment and available resources to meet water and energy needs. The proposed model comprises fixed and variable speed pumps, a grid-connected photovoltaic plant, and two water ponds for internal regulation and storage. The results verify that the combination of self-consumption photovoltaic facilities and variable speed drives make it possible to maximize the percentage of self-consumed energy up to 99.41% during the month with the highest demand for water. In this case, the pumping station reduces its energy costs by 21.56%, in addition to improving water management.

Water Quality Maintenance Approaches and On-Site Monitoring Results of an Artificial Bathing Beach

Ji, Y. and Yin, Y., 2021. Water quality maintenance approaches and on-site monitoring results of an artificial bathing beach. Journal of Coastal Research, 37(4), 793–799. Coconut Creek (Florida), ISSN 0749-0208.The construction of artificial beaches on the muddy coasts involves water purification and long-term maintenance. In the paper, based on the investigation of tidal current, sediment distribution, water quality, and background creatures, a technical scheme of “building submerged breakwater enclosure and accelerating sediment deposition” to form a transparent water body and a long-term water quality maintenance scheme of “diversion, drainage, and self-purification of ecology” are proposed. Through sand precipitation test, water exchange feasibility, and facility scale demonstration, biological purification measures research and on-site practice, as well as long-term water quality monitoring and analysis, the conclusions are as follows: (1) The construction of submerged breakwater for water enclosure promotes the sediment deposition process. The experiment results indicate that after two-day static settlement, 93% of the suspension is precipitated and the concentration of total phosphorus decreased by more than 70%. (2) Water from artificial beaches can be diverted by harnessing tide or pumping facilities. The scale of the pump station and sluice should be determined according to the filling or drainage capability of water in a tidal cycle. (3) The ecological self-purification should be established on the basis of background investigation. The aquatic animals, such as fish, shrimp, crab, shell, and algae m (4) The water quality tends to deteriorate and changes with seasons with the increase of tourists. Finally, it is suggested renovating the current water diversion system, enhancing the monitoring of ecosystem, limiting the number of tourists in summer and increasing the frequency of water exchange.

Water Treatment Plant Operating by Using SCADA

The Water Treatment Plant is responsible for the operation, repair , and maintenance of the City’ s water supply system. This includes all parts of the water system supply chain from: The raw water diversion and pumping facilities to the raw water pipelines • The treatment facilities • The finished water pumping facilities • The finished water storage facilities Testing of SCADA and Automation system for entire Headwork to WTP and Sump & ESR in this WTP premises with Flow meters, Solar power battery , Power & Signal cable, PRV etc completed as per specification.

A simple, low cost and reusable microfluidic gradient strategy and its application in modeling cancer invasion

Microfluidic chemical gradient generators enable precise spatiotemporal control of chemotactic signals to study cellular behavior with high resolution and reliability. However, time and cost consuming preparation steps for cell adhesion in microchannels as well as requirement of pumping facilities usually complicate the application of the microfluidic assays. Here, we introduce a simple strategy for preparation of a reusable and stand-alone microfluidic gradient generator to study cellular behavior. Polydimethylsiloxane (PDMS) is directly mounted on the commercial polystyrene-based cell culture surfaces by manipulating the PDMS curing time to optimize bonding strength. The stand-alone strategy not only offers pumpless application of this microfluidic device but also ensures minimal fluidic pressure and consequently a leakage-free system. Elimination of any surface treatment or coating significantly facilitates the preparation of the microfluidic assay and offers a detachable PDMS microchip which can be reused following to a simple cleaning and sterilization step. The chemotactic signal in our microchip is further characterized using numerical and experimental evaluations and it is demonstrated that the device can generate both linear and polynomial signals. Finally, the feasibility of the strategy in deciphering cellular behavior is demonstrated by exploring cancer cell migration and invasion in response to chemical stimuli. The introduced strategy can significantly decrease the complexity of the microfluidic chemotaxis assays and increase their throughput for various cellular and molecular studies.

Stability of the Emission Characteristics of Thermal and Cold-Field Cathodes Operating in a Vacuum

The features of the use of electron sources based on thermal and field emission in devices of electrovacuum production are considered, including the preservation of the emissive capacity when the operating conditions in a vacuum deteriorate. It is shown that the advantage of metalloporous hot cathodes is the high reduction ability of emission after the device is repeatedly pumped out to the initial pressure. An advantage of high-current field cathodes based on composite diamond-graphite film structures is the stability of the field emission characteristics in a wider range of pressure variations in the device. This improves the operational characteristics of the electrovacuum device (EVD) in the absence of built-in pumping facilities.

International Regulation of Cyber Operations

Cyberspace constitutes an unstable environment, featuring rapid changes in the nature of the actors using it, the technologies applied and the inter-personal, governmental and commercial interactions facilitated thereby. The global COVID-19 pandemic exponentially accelerated the trend of digitalization in various fields of life, increasing even more the dependency on cyber-infrastructure and with it the potential for harmful cyber-attacks. Traditionally, states have been cautious in invoking international law in the context of cyber-attacks, and they tended to refrain from denouncing attacks against them as violations of international law, or attributing it to other states. This state of affairs appears to be changing, however. While there are of disagreements as to the way that international law applies in the cyberspace, a common understanding had emerged about some key international law norms that apply in this field. States like Australia, France, Germany, Israel, the United Kingdom, and the Netherlands have recently articulated their legal positions on how international law applies in cyberspace. In the same vein, states who fell victim to cyber-attacks are increasingly attributing them, as an international law matter, to other states, or non-state actors. Arguably, the increased role played by international law in cyberspace constitutes a reaction to the fact that cyber-attacks become more and more frequent, and dangerous, capable of shutting down critical infrastructure, including nuclear centrifuges and water pumping facilities. This chapter will describe and critically evaluate the norms of international law which regulate cyber-operations, and discuss some of the policy considerations underlying them. Part I offers a short history of cyber-attacks. Part II presents the current international law framework governing cyber-attacks. Part III delves into the attribution challenge in cyberspace. Part IV concludes and suggests a way forward.

Reconsidering the Estimation of Salmon Mortality Caused by the State and Federal Water Export Facilities in the Sacramento–San Joaquin Delta, San Francisco Estuary

Combined water exports from Old River in the south end of California’s San Francisco Estuary (estuary) by state and federal pumping facilities entrain small fishes, including out-migrating juvenile salmon. Both export projects have fish salvage facilities that use behavioral barriers (louvers) in combination with screens to guide fish into collection areas from which they are trucked to release points in the western Delta. Sacramento River-origin Chinook Salmon are regularly taken in the projects’ fish salvage operations. Survival has been estimated within the boundaries of both intake structures, but not in Old River. Prevailing methods for estimating fish losses are based on studies of louver efficiency, near-field survival at the state facility, and assumed survival at the federal facility. The efficiency of the fish salvage operations is affected by several factors, including intake velocity, debris build-up on the louvers and trash racks, and by the omnipresence of predators in front of and within the fish guidance structures. Analysis of existing data suggests that under average conditions, juvenile salmon survive entrainment into the forebay of the state facility at a rate of less than 10%. There is no evidence for better survival at the federal facility. We found no data on predation outside of either the state’s forebay or the federal trash boom, structures which are separated by an approximately 2-km reach of Old River where predation on small fish is thought to be intense. We suggest an improvement to the existing loss estimation, and discuss some features of the studies needed to increase its accuracy and precision.