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Offshore structures are deployed extensively to harvest marine resources. Due to the harsh marine environments and heavy-duty working conditions, the risks associated with failure due to scour are high, and the need for accurate prediction of these risks is increasing. Often, pipelines and cables are critical elements of subsea energy transportation and telecommunication, and they are highly susceptible to scour-induced failure. The scour around spheres is relevant to the offshore industry as a simplified three-dimensional representation of subsea structures. This paper presents a numerical study, using FLOW-3D HYDRO, of the scour around on-bottom cylinders and spheres. Whereas most published research investigated scour around stationary solid objects, this paper presents numerical results of a more challenging case of scour around sagging cylinders and spheres. The model was validated against published experimental and numerical results. The scour depth was found to increase with the decrease of the sagging velocity of the solid object. For sagging horizontal cylinders, the scour depth reaches a plateau of 1.1 times the cylinder diameter when the dimensionless sagging velocity is smaller than 0.094. For sagging spheres, the maximum scour depth reaches 0.37 times the sphere diameter when the dimensionless sagging velocity is reduced to 0.0103. The findings provide guidelines for future research on more complicated interactions between flow, solid objects, and the seabed, accounting for the deformation of infrastructure over time. Practical Applications: This paper concerns the flow, sediment transport, and scour around horizontal cylinders and spheres undergoing slow downward motion, which resembles the sagging of on-bottom infrastructure under the influence of gravity and bed erosion. Offshore structures are deployed extensively to harvest marine resources. Pipelines and cables are critical subsea infrastructures that are susceptible to scour-induced failure. Spherical objects are commonplace in the offshore industry, so a sphere can be deemed as an idealized three-dimensional body. This paper provides detailed FLOW-3D simulations and developed empirical relationships between the dimensionless scour depth and dimensionless sagging speed. Most previous research considered only the scour around fixed objects, so this paper provides a novel addition to the existing knowledge on the scour phenomenon. The computational methods established in this study are useful for simulating more-complicated scenarios. The findings provide guidelines for more-realistic predictions of scour and for the design of scour mitigation measures. [ABSTRACT FROM AUTHOR]

AbstractSteel tubular structures in pipelines, or those connections such as concentric reductions, reduced tees, and elbows, all differ in their response to loading, they are sometimes solicited to complex and combined loads, which accumulate with the internal pressure to their solicitation cause in certain situation their damage, the objective in this analysis is to numerically predict the mechanical behavior until damage of a complete tubular structure, which contains the connecting elements of an elbow and a reduced tee attached to each other by straight tubular parts, this structure, by its standardized dimensions presents a real design of a main pipeline spigot for a possible supply line, this tubular structure is analyzed in this work under these real pressure conditions, and combined loads probably coming from the weight of a valve, or a pipe flanged to this spigot element or other, in X60 steel This structure is solicited under different combined modes of loading. The elastic-plastic behavior is under Voce’s model and Von Mises’ equivalent stress flow theory, the damage of the structure by crack initiation and propagation is ensured by using the XFEM technique, the response up to damage of the structure is evaluated under the effect of the parameters of the combined loading mode, we present by angular bendingrotation moment curves that these parameters clearly condition the response and the level of damage. [ABSTRACT FROM AUTHOR]

This article concerns anisotropy in stress–strain relationships exhibited by steel pipelines. Since the stress from internal pressurization is highest in the hoop direction, standard industrial practice to measure these properties has focussed on tensile testing in this direction, requiring a prior flattening operation. The associated plastic deformation may affect properties, typically causing a (poorly‐defined) degree of hardening and the creation of inhomogeneity. Field testing of such pipelines, requiring in situ measurement of tensile properties (yield stress (YS) and ultimate tensile stress (UTS)), is based on indentation testing of the outer surface. One such test (profilometry‐based indentation plastometry (PIP)), not only gives the stress–strain curve, but also allows detection of any (in‐plane) anisotropy, with a high sensitivity. Both PIP testing and compression testing (with and without prior flattening) have confirmed that none of the eight pipes examined in the current work exhibited any such anisotropy, although the effects of flattening did tend to generate apparent anisotropy in the tensile test outcomes. It may therefore be appropriate to switch the focus of tensile testing to the axial direction, such that no flattening would be required. [ABSTRACT FROM AUTHOR]

Geotechnical centrifuge tests were conducted to examine the influence of invert voids and surface traffic loads on 1400 mm diameter reinforced concrete pipes buried with a shallow soil cover depth of 700 mm. Void formation beneath the pipe was simulated during centrifuge testing. The test results revealed that before void formation, the surface load directly above the middle of the pipe caused a significant increase in not only the circumferential bending moments but also the longitudinal bending moments, the latter of which was considerable and could not be ignored. Void formation beneath the middle of the pipe led to a reduction in both the circumferential bending moments and longitudinal bending moments at all measuring positions, i.e., crown, springline, and invert. The most significant reduction occurred at the invert, and there was even a reversal in the sign of the invert longitudinal bending moment. A comparison was made between centrifuge tests with erosion voids and surface loads at different horizontal positions, which had a marked influence even when the positions differed by half a pipe length. Joint rotation played an important role in relieving large bending moments of pipe barrels in a jointed pipeline when the void and surface load were located at the joint. [ABSTRACT FROM AUTHOR]

When traversing through an active strike-slip fault, buried pipelines may be subjected to permanent ground deformation (PGD), causing large strains in the pipeline during an earthquake. The presence of bends near the fault-crossing zones may further increase the strain in the pipe. Moreover, it is well acknowledged that bends are the most vulnerable location to earthquake damage, mainly when compressive strain develops due to PGD. Hence, most design guidelines recommend constructing pipelines without field bends, elbows, and flanges crossing the fault zone. However, it is not always possible to provide only a straight segment of the pipeline, especially for blind faults where the location of the faults is unknown. Hence, the present study aims to investigate the response of buried continuous steel pipelines with field bends subjected to strike-slip faulting by conducting an extensive parametric study. A three-dimensional pipe-soil interaction model is developed in a finite element framework for this study. The pipeline response in terms of its maximum von-Mises stress and maximum longitudinal stress and strain due to fault crossing is studied for various influencing parameters such as pipe bend angle, soil strength, pipe burial depth, and distance of the fault trace from the bend. Based on the results obtained, suitable relationships in terms of modification factors over the response of a straight pipeline as a function of a few critical parameters are determined using regression analyses. It is concluded that providing bends to the pipeline can significantly affect its structural response when subjected to fault displacement when the fault trace is close to the pipe bend. The primary outcome of this investigation would be to suggest a simplified methodology to estimate the response of pipelines having field bends while crossing fault lines from the response of straight pipelines in a similar scenario. [ABSTRACT FROM AUTHOR]

Quantum computing, with its superior computational capabilities compared to classical approaches, holds the potential to revolutionize numerous scientific domains, including pharmaceuticals. However, the application of quantum computing for drug discovery has primarily been limited to proof-of-concept studies, which often fail to capture the intricacies of real-world drug development challenges. In this study, we diverge from conventional investigations by developing a hybrid quantum computing pipeline tailored to address genuine drug design problems. Our approach underscores the application of quantum computation in drug discovery and propels it towards more scalable system. We specifically construct our versatile quantum computing pipeline to address two critical tasks in drug discovery: the precise determination of Gibbs free energy profiles for prodrug activation involving covalent bond cleavage, and the accurate simulation of covalent bond interactions. This work serves as a pioneering effort in benchmarking quantum computing against veritable scenarios encountered in drug design, especially the covalent bonding issue present in both of the case studies, thereby transitioning from theoretical models to tangible applications. Our results demonstrate the potential of a quantum computing pipeline for integration into real world drug design workflows. [ABSTRACT FROM AUTHOR]

A novel approach was developed based on real conditions to calculate the amount of contamination between sequential fluids in multiproduct pipelines. Besides, the fluid shift time at the source terminal and the pipeline's pressure gradient were used as new critical parameters for estimating initial-interfacial mixing. Also, a new correlation was presented using the experimental evaluation (i.e. monitoring the mixing growth along pipelines) and numerical modeling. The proposed equation showed acceptable results compared to the field data collected from the 55-km-long 10-in diameter and 136-km-long 16-in diameter pipelines. Increasing the initial mixing during the fluid change at the source terminal significantly enlarges the contamination. [ABSTRACT FROM AUTHOR]

Aiming at the problems of low target detection accuracy and high leakage rate of the current traditional weld surface defect detection methods and existing detection models, an improved YOLOv7 pipeline weld surface defect detection model is proposed to improve detection results. In the improved model, a Le-HorBlock module is designed, and it is introduced into the back of fourth CBS module of the backbone network, which preserves the characteristics of high-order information by realizing second-order spatial interaction, thus enhancing the ability of the network to extract features in weld defect images. The coordinate attention (CoordAtt) block is introduced to enhance the representation ability of target features, suppress interference. The CIoU loss function in YOLOv7 network model is replaced by the SIoU, so as to optimize the loss function, reduce the freedom of the loss function, and accelerate convergence. And a new large-scale pipeline weld surface defect dataset containing 2000 images of pipeline welds with weld defects is used in the proposed model. In the experimental comparison, the improved YOLOv7 network model has greatly improved the missed detection rate compared with the original network. The experimental results show that the improved YOLOv7 network model mAP@80.5 can reach 78.6%, which is 15.9% higher than the original model, and the detection effect is better than the original network and other classical target detection networks. [ABSTRACT FROM AUTHOR]

Steel pipelines used for oil and gas transmission are at risk of stress corrosion cracking (SCC). Extensive research has been carried out to evaluate the SCC susceptibility of pipeline steels. Those research studies were mainly specific to the steels of pipes without welding. In this research, pieces of X65 steel plates were welded by the shielded metal arc welding process. The speeds of electrode travel were set as the main welding parameter. Slow strain rate tests (SSRTs) in the air and the NS4 standard solution were conducted. The results showed that the tensile behavior of the samples in the solution was very different from that in the air. For the samples tested in the solution, the strength amounts of the weld zones were higher than the strength of the base metal, but in the case of SSRT in the air, the strength of the base metal was higher. As a result, the UTS strength of one of the weld zones reached levels as high as 480 MPa and also 34% elongation under the SSRT. Therefore, the conditions of welding have a high degree of importance and must be controlled to have less SCC susceptibility. [ABSTRACT FROM AUTHOR]

Entrapped air pockets in water pipelines play a significant role in influencing transient over-pressures during filling procedures. Several research is focused on highlighting the attenuation of pressure peaks in pipes with single air pockets. This research studies the air-water interaction during rapid water filling processes in an irregular pipeline and air pockets in different branches, and how the trapped air can attenuate the over-pressure peaks. A three-dimensional computational fluid dynamics (CFD) model was developed, and numerical results of the model were validated through experimental measurements. For a given initial air pocket condition upstream of the high point, the maximum air pocket over-pressure was 11% to 32% lower when the descending pipe segment initially contains air compared to when it contains water. In sum, it was found that entrapped air pockets at high points of water pipelines can help mitigate transient over-pressures considering specific initial hydraulic conditions prior to filling operations. [ABSTRACT FROM AUTHOR]

This study explores the microstructural characterization of pearlite phase transformation in high-strength low-alloy API X60 steel, which is used in pipelines. Understanding the formation, phase percentages, and morphology of the pearlitic phase is crucial since it affects the mechanical properties of the considered steel. In this research, a phase-field model, particularly the Cahn-Hilliard approach, was used in order to simulate the formation and morphology of the pearlite phase in response to different heat treatments. Both double- and triple-well potentials were considered for comprehensively studying pearlite's morphology in the simulations. The simulation results were then compared with experimental outcomes obtained by metallography and field-emission scanning electron microscopy analyses. Considering the doublewell potential can help simulate only two phases, ferrite and cementite, which is less compatible with the experiment results than the triple-well potential, which gives the possibility of simulating a three-phase microstructure, ferrite, cementite, and austenite, and a better match with experimental data. The study revealed that as the cooling rate increases, the interlamellar spacing and layer thickness decrease. Additionally, the difference between experimental and simulation results using triple-well potential was approximately ~10%. Therefore, triple-well potential formulation predictions have better agreements with experimental results for the development circumstance of pearlitic structures. [ABSTRACT FROM AUTHOR]

This paper focuses on the performance of a braced deep excavation in soft soil based on field monitoring and numerical modeling. Laboratory tests were conducted to determine the soil parameters used in the modified Cam-Clay (MCC) model. Intelligent field monitoring means were adopted and a three-dimensional model was established. Spatial and temporal effects induced by the excavation are investigated for the deep-large foundation pit in soft soil. Deformation characteristics of the enclosure structure and the surrounding environment throughout the excavation process are presented. The behaviors of diaphragm walls, columns, the maximum wall deflection rate, ground surface settlement, and utility pipelines were focused on and investigated during the whole excavation process. Besides, the axial forces of the internal supports are analyzed. Based on the measured and simulated data, the following main conclusions were obtained: the numerical simulation results are in good agreement with the measured values, which proves the accuracy of the model parameters; the wall and the ground surface showed the maximum displacement increment at stage 9, which was a coupled product of the "creep effect" of the soft soil in Nanjing, China and the "depth effect" of the excavation; as the excavation progressed, the ground settlement changed from a "rising" to a "spoon-shaped" trend, dvm was measured between dvm = 0.0686%H and dvm = 0.1488%H; the rebound deformation curve of the pit bottom was corrugated, and the depth of disturbance of the pit bottom after the completion of soil unloading was 2-3 times the excavation depth; the closer the pipeline is to the corner of the pit, the less the excavation process will affect the settlement of the pipeline and the less the obvious pit corner effect will occur; the support strength of the buttress and the longest corner brace should be strengthened during the actual construction process to ensure the stability of the foundation deformation. [ABSTRACT FROM AUTHOR]

Cooperation in the energy sector, and practically in the field of hydrocarbons, is traditionally and reasonably considered as an important area of multidisciplinary interaction between the Russian Federation and the People's Republic of China. In terms of its substantive forms, the energy dialogue has a multifaceted character, includes cooperation in mineral exploration, production technologies, capacity generation, investment support for relevant projects. Nevertheless, as it was objectively developed in practice, one of the main elements of cooperation turned out to be the supply of hydrocarbons from Russia to China, which has been increasing since the beginning of the century. This situation reflects the natural complementarity of the economic complexes of the two countries, which, in turn, serves as one of the basic foundations for the compatibility of the national interests of the Russian Federation and the People's Republic of China. Paying attention to the circumstances above, the author examines the specific practice of cooperation in the field of hydrocarbon supplies, including the documents signed and the projects already implemented or being discussed. The focus is made on the current situation, when, in the context of large- scale sanctions pressure from the West, the task of reorientation of domestic energy exports to the East, including to China, is being considered systemically important for Russia. Pointing out the existing difficulties, the article contains a conclusion about the overall positive prospects for Russian-Chinese hydrocarbon cooperation.

Abstract The deep‐sea ground contains a huge amount of energy and mineral resources, for example, oil, gas, and minerals. Various infrastructures such as floating structures, seabed structures, and foundations have been developed to exploit these resources. The seabed structures and foundations can be mainly classified into three types: subsea production structures, offshore pipelines, and anchors. This study reviewed the development, installation, and operation of these infrastructures, including their structures, design, installation, marine environment loads, and applications. On this basis, the research gaps and further research directions were explored through this literature review. First, different floating structures were briefly analyzed and reviewed to introduce the design requirements of the seabed structures and foundations. Second, the subsea production structures, including subsea manifolds and their foundations, were reviewed and discussed. Third, the basic characteristics and design methods of deep‐sea pipelines, including subsea pipelines and risers, were analyzed and reviewed. Finally, the installation and bearing capacity of deep‐sea subsea anchors and seabed trench influence on the anchor were reviewed. Through the review, it was found that marine environment conditions are the key inputs for any offshore structure design. The fabrication, installation, and operation of infrastructures should carefully consider the marine loads and geological conditions. Different structures have their own mechanical problems. The fatigue and stability of pipelines mainly depend on the soil‐structure interaction. Anchor selection should consider soil types and possible trench formation. These focuses and research gaps can provide a helpful guide on further research, installation, and operation of deep‐sea structures and foundations.

This article presents a comprehensive improvement in the experimental analysis of cracking processes in smooth and sharp V-notched samples taken from gas transport pipelines, utilizing the acoustic emission (AE) method. The research aimed to establish a robust correlation between the failure mechanisms of uni-axially tensile samples and the distinct characteristics of AE signals for enhanced quality management in pipeline integrity. The study encompassed materials from two different straight pipe sections, encompassing both long-term used materials and new, unused materials. Through the application of the k-means grouping method to AE signal analysis, we achieved the identification of AE signal parameters characteristic of various stages of the material destruction process. This advancement introduces a significant improvement in monitoring and managing the operational safety of pipeline networks, offering a methodology that leverages advanced acoustic emission signal analysis. The outcomes present significant implications for the pipeline industry by proposing methods to enhance safety systems and more effectively manage the integrity and quality of gas infrastructure.

Abstract Background The initial version of SEDA assists life science researchers without programming skills with the preparation of DNA and protein sequence FASTA files for multiple bioinformatics applications. However, the initial version of SEDA lacks a command-line interface for more advanced users and does not allow the creation of automated analysis pipelines. Results The present paper discusses the updates of the new SEDA release, including the addition of a complete command-line interface, new functionalities like gene annotation, a framework for automated pipelines, and improved integration in Linux environments. Conclusion SEDA is an open-source Java application and can be installed using the different distributions available ( https://www.sing-group.org/seda/download.html ) as well as through a Docker image ( https://hub.docker.com/r/pegi3s/seda ). It is released under a GPL-3.0 license, and its source code is publicly accessible on GitHub ( https://github.com/sing-group/seda ). The software version at the time of submission is archived at Zenodo (version v1.6.0, http://doi.org/10.5281/zenodo.10201605 ).

Hydrogen embrittlement (HE) of steel pipelines in high-pressure gaseous environments is a potential threat to the pipeline integrity. The occurrence of gaseous HE is subjected to associative adsorption of hydrogen molecules (H2) at specific “active sites”, such as grain boundaries and dislocations on the steel surface, to generate hydrogen atoms (H). Non-metallic inclusions are another type of metallurgical defect potentially serving as “active sites” to cause the dissociative adsorption of H2. Al2O3 is a common inclusion contained in pipeline steels. In this work, the dissociative adsorption of hydrogen at the α-Al2O3(0001)/α-Fe(111) interface on the Fe011¯ plane was studied by density functional theory calculations. The impact of gas components of O2 and CH4 on the dissociative adsorption of hydrogen was determined. The occurrence of dissociative adsorption of hydrogen at the Al2O3 inclusion/Fe interface is favored under conditions relevant to pipeline operation. Thermodynamic feasibility was observed for Fe and O atoms, but not for Al atoms. H atoms can form more stable adsorption configurations on the Fe side of the interface, while it is less likely for H atoms to adsorb on the Al2O3 side. There is a greater tendency for the occurrence of dissociative adsorption of O2 and CH4 than of H2, due to the more favorable energetics of the former. In particular, the dissociative adsorption of O2 is preferential over that of CH4. The Al-terminated interface exhibits a higher H binding energy compared to the O-terminated interface, indicating a preference for hydrogen accumulation at the Al-terminated interface.

AbstractDespite the fact that most police departments in the U.S. serve jurisdictions with fewer than 10,000 residents, policing practices in small towns are understudied. This is due in part to data limitations and technological barriers that exist in the small-town context. In this article we focus on one small town police department in New England with a history of misconduct, and develop a comprehensive data science pipeline that addresses the stages from design and collection to reporting. We present the reader with specific tools in the open-source Python ecosystem for replicating this pipeline. Once these data are processed, we perform two statistical analyses in an attempt to better understand the provisions of service by the small-town police department of focus. First, we perform ecological inference to estimate the rate at which residents are placing calls for service. Second, we model wait times using a negative binomal regression model to account for overdispersion in the data. We discuss data and model limitations arising through the pipeline creation and analysis process. [ABSTRACT FROM AUTHOR]

Meeting Germany's climate targets urgently demands substantial investment in renewable energies such as hydrogen, as well as tackling industrial CO2 emissions with a strong CO2 transport infrastructure. This is particularly crucial for CO2-heavy industries such as steel, cement, lime production, power plants, and chemical plants, given Germany's ban on onshore storage. The CO2 transport network is essential for maintaining a circular economy by capturing, transporting, and either storing or utilizing CO2. This study fills gaps in CO2 pipeline transport research, examining pipeline diameters, costs, and pressure drop, and providing sensitivity analysis. Key findings show that the levelized cost of CO2 transport (LCO2T) ranges from 0.25 €/t to 55.82 €/t based on varying transport masses (1000 t/day to 25,000 t/day) and distances (25 km to 500 km), with compression costs pushing LCO2T to 33.21 €/t to 92.82 €/t. Analyzing eight pipeline diameters (150 mm to 500 mm) and the impact of CO2 flow temperature on pressure loss highlights the importance of selecting optimal pipeline sizes. Precise booster station placement is also crucial, as it significantly affects the total LCO2T. Exploring these areas can offer a more thorough understanding of the best strategies for developing cost-effective, efficient, and sustainable transport infrastructure. [ABSTRACT FROM AUTHOR]

Early damage in metal materials is primarily characterized by microdefects, such as microcracks and micropores. In this study, we developed a novel approach for quantitatively assessing the microdefect damage degree in dual-phase bainite–ferrite (B + F) X80 pipeline steel using ultrasound nonlinear parameters. A finite element analysis model with micron-scale three-dimensional ellipsoidal defects was established based on the Gurson–Tvergaard–Needleman material damage theory. The propagation process of Lamb waves in the model was simulated to investigate the interaction mechanism between microdefects and Lamb waves and explore the quantitative relationship between ultrasound nonlinearity and microdefect damage degree, which can be characterized by the size and number of microdefects. Furthermore, to validate the simulation findings, an ultrasound testing experiment was designed to evaluate the microdefect damage in (B + F) X80 pipeline steel. The results demonstrate that when Lamb waves propagate through microdefects, their amplitude is attenuated, resulting in changes in ultrasound nonlinear parameters. Within a specific range, the nonlinear coefficient of Lamb waves increases with an increase in microdefect length and number of microdefects but decreases with an increase in microdefect width. This finding holds significant value for evaluating damage degree and predicting the service life of X80 pipeline steel. [ABSTRACT FROM AUTHOR]

This article explores how sound technologies are deployed by government agencies to produce legitimacy in the struggle over oil pipelines in British Columbia, Canada. Activists seeking to stop the Northern Gateway and Trans Mountain pipelines have mobilized noise and silence as tactics of protest and refusal. For example, one thousand demonstrators make a cacophony outside a Vancouver hotel in protest of the Northern Gateway pipeline. Communications technology, though, is deployed here by the state to compress and control. In one of the hotel's small, impregnable conference rooms, public hearings over the pipeline are taking place—only the public is not allowed inside: the proceedings are being livestreamed to a hotel two kilometers away. On unceded Coast Salish territory, the legitimacy of pipeline hearings is also contested because the continued existence of Indigenous legal orders represents a challenge to the pipelines in question. Technological mediation makes it possible to satisfy one requirement of legitimacy: democratically granted representative power. The challenge to the legal system highlighted by the continued existence of the Indigenous, though, is managed through audile techniques deployed as anthropotechnologies. The implications for a politics of sound must be considered in light of sound's mediation, which is never politically neutral. [ABSTRACT FROM AUTHOR]

Magnetic flux leakage (MFL) is one of the most commonly used non-destructive testing technologies for defect detection of oil and gas pipelines. Analysing the MFLsignals of different defects and thus identifying the types and sizes of pipeline defects are the key and difficult points, obtaining wide attention in both academic and engineering domains. Most of the past research has focused on the MFL signals of single defects, neglecting the interference caused by adjacent defects, possibly leading to errors. As a result, this study develops a finite element method (FEM) model based on Maxwell theory for the MFL signal of adjacent defects and analyses the signal characteristics, considering both inner and outer defects The interference distances caused by inner and outer defects are analysed and the shape and size of the defects are also considered to identify defects in multiple adjacent defects. The model results show that the interference caused by adjacent defects manifests the superposition of the leakage magnetic field in axial and radial components. The interference weakens with increasing distance between adjacent defects. To quantify the interference caused by different defects, a concept of interference distance' is developed using the change rate of the peak value of MFL signals. The influence of different factors on the interference distance is explored by analysing the MFL signal under different factors. Therefore, this study can support the identification of adjacent defects on steel pipelines using MFLtechnology, reducing the errors caused by adjacent defects. [ABSTRACT FROM AUTHOR]

This paper studies the optimization of hydraulic parameters for pipeline system of hydropower station with super long headrace tunnel (HSSLHT) based on mayfly algorithm considering operational scenarios. Firstly, the state equation of HSSLHT under load disturbance is derived. The optimization design of hydraulic parameters for pipeline system based on mayfly algorithm is proposed. Then, the optimization of hydraulic parameters is conducted and analyzed. Finally, the effects of pipeline diameters and transfer coefficients of turbines on the optimization of hydraulic parameters for pipeline systems are revealed. The results show that the optimization of hydraulic parameters for pipeline system is a multiobjective problem, and the several objective functions exhibit significant conflicts. Compared to the firefly algorithm and genetic algorithm, the objective function under mayfly algorithm is improved by 14.7% and 5.1%, respectively. The mayfly algorithm can make the hydraulic parameters for the pipeline system reach the Pareto optimal solution under both load decrease condition and load increase condition. The diameter of penstock has an obvious influence on the robustness of dynamic performance of HSSLHT. When the diameter of penstock increases by 30%, the robustness of HSSLHT becomes worse and the robustness index deteriorates by 57%. The reason is that the flow inertia of penstock becomes smaller with the increase of diameter, and the flow inertia of penstock is favorable for resisting disturbance of HSSLHT. The coefficient of throttled orifice head loss and the lengths and head losses of headrace tunnel and penstock are the key hydraulic parameters for matching the operation of HSSLHT. [ABSTRACT FROM AUTHOR]

Building and testing software for embedded systems can be challenging with an impact on delivery time, design reproducibility, and collaboration among project contributors. To accelerate project development, presented here is an automated build flow that utilizes Xilinx PetaLinux, and field programmable gate array (FPGA) hardware description and integrates with the GitLab continuous integration and continuous deployment (CI/CD) framework for embedded targets. This build flow automates the complete process of FPGA implementation, PetaLinux configuration, and cross-compilation of software essentials for the target system-on-chip (SoC). The system has been successfully deployed in cross-compiling the control and command toolset for the Positron Emission Tomography scanner (PhenoPET) and the implementation of the message queuing telemetry transport (MQTT) service on a Xilinx Zynq Ultrascale MPSoC. This approach can be easily adapted to other projects with specific requirements. [ABSTRACT FROM AUTHOR]

Water losses in water distribution systems are typically analysed using extended period simulations, where its numerical resolution is commonly achieved using the gradient method. These models assume that adjustments to regulating valves occur, either manually or automatically, over an extended period of time, then the system inertia can be neglected. This research introduces the development of a rigid water column model for analysing water leakages in single pipelines, which can be employed to account for regulation valve adjustments in shorter time periods, thereby providing greater accuracy when assessing water losses. The application to a case study is presented to analyse pressure variations and leakage flow patterns over 30, 60, and 180 s. A comparison between the extended period simulation and rigid water column model is presented in order to note the order of magnitude on leakages when the system inertia is not considered. The results confirm that is crucial for water utilities the consideration of inertial system to simulate adequately opening and closure manoeuvres in water distribution systems, since according to the case study the extended period simulation can overestimated or underestimated the total leakage volume in percentages of 37.1 and 55.2 % , respectively. [ABSTRACT FROM AUTHOR]

To explore the solution of the two-step method applied in the rapid construction of super large cross-section tunnels passing through IV-and V-grade surrounding rock sections in karst cave areas, based on an engineering example of the Lianhuashan Tunnel, we use the numerical calculation method to analyze the stability of surrounding rock and the design parameters of the control measures for super large cross-section tunnels during the construction of the step method. The calculated results show that the working face of IV-grade surrounding rock can be stabilized by an advanced small pipe, and the stability of the supporting structure should be controlled mainly by IV-grade surrounding rock. In order to control the stability of the tunnel face, it is necessary to use an advanced large pipe shed in the surrounding V-grade rock. The reinforcement range of the advanced large pipe shed is 120° and the length is 20 m. This is the most economical design parameter of the advanced large pipe shed, ensuring the deformation control effect. For control of the stability of the supporting structure, under the condition that the working space is suitable for large machinery, the settlement of the arch of the supporting structure can be obviously reduced by shortening the step cycle footage and reducing the step length, and the peripheral convergence of the supporting structure can be obviously reduced by reducing the step height. After comprehensive analysis and considering the development of karst caves, the advanced support measures, design parameters, bench excavation design parameters, initial support measures, karst cave treatment measures, and bench construction process of IV- and V-grade surrounding rock is determined. The application verification shows that the research results have a good control effect on the stability of the surrounding rock and cave and are suitable for large-scale mechanical operations, which can significantly improve the excavation speed of the super large cross-section tunnel passing through the IV- and V-grade surrounding rock sections in the karst cave area. [ABSTRACT FROM AUTHOR]

Hydrogen embrittlement (HE) of steel pipelines in high-pressure gaseous environments is a potential threat to the pipeline integrity. The occurrence of gaseous HE is subjected to associative adsorption of hydrogen molecules (H2) at specific "active sites", such as grain boundaries and dislocations on the steel surface, to generate hydrogen atoms (H). Non-metallic inclusions are another type of metallurgical defect potentially serving as "active sites" to cause the dissociative adsorption of H2. Al2O3 is a common inclusion contained in pipeline steels. In this work, the dissociative adsorption of hydrogen at the α - A l 2 O 3 (0001) / α - F e (111) interface on the F e 01 1 ¯ plane was studied by density functional theory calculations. The impact of gas components of O2 and CH4 on the dissociative adsorption of hydrogen was determined. The occurrence of dissociative adsorption of hydrogen at the Al2O3 inclusion/Fe interface is favored under conditions relevant to pipeline operation. Thermodynamic feasibility was observed for Fe and O atoms, but not for Al atoms. H atoms can form more stable adsorption configurations on the Fe side of the interface, while it is less likely for H atoms to adsorb on the Al2O3 side. There is a greater tendency for the occurrence of dissociative adsorption of O2 and CH4 than of H2, due to the more favorable energetics of the former. In particular, the dissociative adsorption of O2 is preferential over that of CH4. The Al-terminated interface exhibits a higher H binding energy compared to the O-terminated interface, indicating a preference for hydrogen accumulation at the Al-terminated interface. [ABSTRACT FROM AUTHOR]

This study employs a statistical regression technique to investigate the maximum displacement, stress, and natural vibration frequencies of a submarine pipeline subjected to hydrodynamic wave forces. Eighteen pipeline models are designed, varying in wall thickness from 10 mm to 30 mm and diameter from 500 mm to 1000 mm. The hydrodynamic drag and inertia forces are performed by using the Morison equation. Computer-aided Finite Element Analysis is employed to simulate the complex interactions between the fluid and structure in 18 pipelines. Multiple Regression technique is used to evaluate the reliability metrics, considering uncertainties in geometrical properties affecting pipeline performance. Full Quadratic models are developed for expressing more effective and concise mathematical equations. Analysis of Variance (ANOVA) is performed to determine the adequacy of the model in representing the observed data. The Coefficient of Determination (R2), Mean Square Error (MSE), and Mean Absolute Error (MAE) are calculated to assess the equation's predictive accuracy and reliability. The results confirm the suitability of the suggested regression technique for analyzing the relationships between predictor variables and the response variable. [ABSTRACT FROM AUTHOR]