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AbstractA major hazard to embankment dams is internal erosion and piping arising from concentrated leaks through cracks in the core due to differential settlement. Previous work (Peirson et al., 2023) quantified the hydraulics of flow through near-surface transverse cracks subject to near-horizontal pressure gradients. This present short note extends the previous work to address pressurised flow through cracks that might occur deeper within the core. Water speeds, hydraulic shear stresses, flows are computed as a function of the applied hydraulic gradient. These results extend previous work addressing the hydraulics of very narrow cracks. [ABSTRACT FROM AUTHOR]

Applying isolation devices to nuclear power plant equipment can improve the equipment's seismic safety. When the equipment is connected to piping, however, its seismic safety can rather be decreased due to the increase in the relative displacement of the connected pipes. An emergency diesel generator (EDG) supplies power when a generator and an external power source in a nuclear power plant do not operate. Isolation devices can be installed to improve EDG's seismic safety. The seismic safety of EDG is generally evaluated considering only EDG and the isolation device. Since the piping connected to EDG is responsible for fuel supply and cooling, however, the seismic safety of EDG must be evaluated considering the piping as well. In this study, seismic fragility analyses were conducted according to the modeling of isolation devices for EDG equipped with the isolation device and the piping connected to EDG. Seismic response analyses were performed considering the fuel line in EDG to which the seismic isolation devices were applied, and seismic fragility curves were estimated based on the results of the seismic response analysis. The research results showed that the piping connected to EDG could be damaged earlier than EDG, indicating that proper piping system design and seismic safety assessment are required to apply isolation devices to EDG. [ABSTRACT FROM AUTHOR]

In the evaporation crystallization unit of wet flue gas desulfurization process, the medium inside the pipeline is mainly a liquid-solid two-phase fluid. Improper equipment layout and pipeline design can easily cause solid particle precipitation and deposition, resulting in certain erosion and wear on pipelines, elbows, etc. Starting from engineering practice, this article systematically reviews the layout and pipeline design of the main equipment of an evaporative crystallization system in a certain device. A fluid flow model ( CFD) is used to simulate and analyze the erosion of elbows with different curvature radii that affect the long-term operation of the device. The distribution of fluid velocity field, pressure distribution, particle motion path, and erosion rate inside the pipeline are studied. It is proved that using 3D, 6D and other curvature radius elbows can effectively reduce the erosion and wear of solid particles on the pipeline in the fluid, ensuring the long-term operation of the device. [ABSTRACT FROM AUTHOR]

Barium sulfate crystals are minerals responsible for scaling in piping systems. Controlling the growth of these crystals can use additives (FeCl2 and SrCl2) and varying agitation speeds. The research was to optimize the impact of additives and agitation speed on the results of crystal form using RSM through Minitab 19 with Box-Behnken Design. The optimum conditions using additive FeCl2 at a concentration of 25 ppm, a stirring speed of 120 rpm for 30 minutes, and a coefficient of determination (R2) of 90.995 provided 0.4485 gr of barium sulfate crystals. The optimum conditions, however, used SrCl2 additives at a concentration of 20.2049 ppm and a stirring speed of 459.394 rpm for 30 minutes, yielding 0.4345 g of barium sulfates with a coefficient of determination (R2) of 91.41%. The results of crystallizing barium sulfate without additives appear to be superior to those obtained with additives in terms of production. In contrast, additives of FeCl2 and SrCl2 can inhibit barium sulfate formation, resulting in a reduction in crystal mass. [ABSTRACT FROM AUTHOR]

Water extraction in agricultural fields with high saturation levels requires drainage systems that increase land preparation costs, so looking for new options for materials that function as drainage pipes that provide a better technical–economic relationship is crucial. In this study, Manning roughness values were analyzed in the culms of Guadua angustifolia considering three factors: flow, section, and location site of the forest stands. This study was carried out in the rural area of the municipality of Pitalito; the characterization of culms was made based on the Colombian technical standards (NTC) 5726 and 5727, the cutting and elaboration of test pieces according to the NTC 5525, and finally, the hydraulic tests were carried out. The roughness values oscillated between 0.1089 and 0.0337 according to the different flow evaluated values in the laboratory tests, between 0.1004 and 0.0356 for the sections analyzed, and between 0.0909 and 0.0533 according to the sample extraction area. The multifactor ANOVA established a significant relationship for the flow and section on the Manning n roughness, while the zone was insignificant. [ABSTRACT FROM AUTHOR]

Analysis of structures is done in two ways reliance matrix and stiffness matrix methods. In the soft method, the unknowns of the problem are forces. In the soft methods, we need an additional equation for the number of statically indeterminate degrees. In our hardness method, the unknowns are the deformation of the structure, and after obtaining them, the unknown forces of the structure can be obtained. Also, for structures that have a low degree of uncertainty but a high degree of freedom, the soft method is easier, but for structures that have a low degree of freedom, the hard method is good. In this article, we have investigated the structure related to the pipelines of a station, such as the gas pressure boosting station, using the stiffness method. Pipeline systems under thermal loads are frequently used in many systems are relate to in oil and gas like power stations or pumping houses and petrochemicals and gas stations. Unlike the analytical center of elastic method, which can analyze only a single branch of pipeline with members the coordinate system installed parallel to the pipe, the stiffness method removes these kinds of limitations. In this article, the stiffness method is introduced to analyze pipeline systems. Based on this method, the piping system may include any numbers of pipe branches. The straight elements of pipe in the branch may have any general orientation, and the bend elements may have any arbitrary angle. The computer program designed based on this method may compute the nodal displacements at the ends of the straight or bent elements and present three components for loads and three for moments. Once the free-body diagram of each piping element with nodal forces and moments is drawn, the engineering codes are employed to design the piping system for safe operation. By using this method every kind of pipelines including constraint and unconstraint could be analysed. As we know in powerplant and pipeline systems, thermal stresses are one of the major problems. Every year this phenomenan cause many damages for industries then computing and predicting the effect of thermal loads are very essential for engineeres. Stiffness method is a general and simple method for computing nodal forces for piping or pipeline systems and every kind of pipelines with any geometric plan and every number of branch of pipes. Maximum forces and moment could be computed in every point of system and then the best position for installation of hangers and foundations can be determined. [ABSTRACT FROM AUTHOR]

Copyright of Dokuz Eylul University Muhendislik Faculty of Engineering Journal of Science & Engineering / Dokuz Eylül Üniversitesi Mühendislik Fakültesi Fen ve Mühendislik Dergisi is the property of Dokuz Eylul Universitesi Muhendislik Fakultesi Fen ve Muhendislik Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents a new control method for surge instability of the compressor system. Due to the importance of the active control approach in improving the efficiency of the compressor system, a new scheme based on the model predictive control (MPC) technique has been considered to control surge which gives the benefits of control signal optimization by considering the constraints on states and input. Because of designing a novel MPC by using of linear matrix inequality scheme, the optimization problem is solved in less time and with less complexity. The proposed method is able to consider the limitation of the close coupled valve actuator and also covers the uncertainty on the model. In addition, the developed model describes the nonlinear behaviour of the compressor system and handles the effects of the pipe on surge instability. Using Lyapunov theory, the stability of the closed-loop system under the proposed robust active controller is shown. The simulation results show the high pressure and high efficiency operation of the system under study in different operating conditions. [ABSTRACT FROM AUTHOR]

The critical hydraulic gradient ( i cr ) for internally unstable soils is observed to be significantly less than the i cr given by Terzaghi's classical equation. The difference is due to the uneven stress contributions by fine and coarse fractions of internally unstable soils, and thus an empirical stress reduction factor ( α) was considered for i cr predictions. Internally unstable soils are coarse fraction dominant with a void ratio of the fine fraction higher than the void ratio of overall internally unstable soil. The differential stress states lead to washout of the fines from the local voids of the coarse fraction at a hydraulic gradient of less than the i cr given by the classical equation. This study presents a theoretical approach for predicting α based on the notion of the effective stress of the fine fraction within the voids of a coarse fraction being equal to zero for internally unstable soils. A comparison of predicted i cr based on the proposed approach and experimental observations obtained from the literature and the current study has demonstrated the validity of the proposed approach. The applicability of the proposed approach is also illustrated for the estimation of a critical hydromechanical envelope. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas & Oil is the property of Editorial Department of Natural Gas & Oil and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describes the experimental methods developed to understand the piping erosion of impervious core and its interaction with downstream filters in embankment dams. Concentrated leaks through a dam core-filter system are simulated experimentally in the hole erosion filter test (HEFT). The mass rate of erosion in the base soil, the eroded soils entrapped in the downstream filters, and the eroded soil particles passed through the filters that settled in the test unit and suspended in the effluent were derived throughout the test. An interpretation method of test results and determination of the rate of erosion of the dam core with downstream filters are proposed for which no methods are reported in the current literature. Results of experimental investigations indicated that the mechanism of erosion in a soil-filter system and the rate of erosion are influenced dominantly by the relative particle size distribution of base soils and filters, applied hydraulic gradient, coefficient of soil erosion, and dry density of base soil. For the soils and filters tested, the average erosion rate of a specimen compacted to 88% of the standard maximum dry density of soil compacted at standard optimum moisture content, Mdd, is about 4.1 times that of specimen with 97% Mdd. The average erosion rate for soil with erosion coefficient 1.54×10−5 s·m−1 is about 15.4 times of that for soil with erosion coefficient 3.8×10−6 s·m−1 for the same downstream filter and hydraulic gradient. The average erosion rate for a hydraulic gradient of 27.17 is about 2.2 times that for a hydraulic gradient 18.9 for the same soil and filter tested. Application of the HEFT for assessing the piping risk rating of embankment dams is presented. The practical applications of the HEFT presented in this paper extend to the assessment of the piping risk rating of embankment dams. These findings provide a valuable foundation for improving dam safety protocols and the design and maintenance of embankment dams. By gaining a deeper understanding of the factors influencing piping erosion, dam engineers and geotechnical professionals can make informed decisions to enhance the resilience and safety of embankment dam structures, ultimately minimizing the risks associated with this critical geotechnical issue. [ABSTRACT FROM AUTHOR]

In this paper, we present the results of the geomorphological study of the micro pseudokarst landfoms developed on Pâclele Mari mud volcanic site that belongs to the famous mud volcanic area Berca-Arbănași, Buzău Subcarpathians, Romania. Different types of pseudokarstic cavity formation can be observed in the area, especially in the sloping periphery of the mud volcanic area, where badlands developed (badland pseudokarst), and rheogene pseudokarst in the mud flows. The liquid mud material gets denser and wimple on the surface of the mud that flows in the trough, it compiles and then covers the liquid mud channel. These micro-size covered tunnels are similarly formed as lava tubes at the lava flows of real volcanic areas. In order to complement the field measurements, we carried out surveys with a DJI Phantom 3 and 4, and Mavic Pro quadcopter to determine the landforms for the photogrammetry. Granular composition tests were carried out on sediment samples collected in the mud volcanic area by a laser diffraction particle analyser.

Control of large structures often involves the use of hydraulic equipment due to the large power requirements. In this study, a large telescope is taken as an example of a large structure. A large telescope is equipped with hydraulic support systems to adjust the deformation of the structure, as changes in its pointing direction and ambient temperature deform the structure and reduce the telescope's observational performance. In previous studies, hydraulic support system elements and piping paths have been discussed, but quantitative evaluations and design considerations for the overall system performance of multiple hydraulic support systems and telescope structures have not been discussed. In this paper, simple transfer function models are derived for a coupled system of multiple hydraulic support systems and telescope structures, which allow the static and dynamic transient response characteristics to be evaluated. A design example using these transfer function models is also proposed and it is shown that the selected design parameters enable the large telescope to meet the specifications.

The piping system connected with the shipboard equipment may be subjected to excessive vibration due to harmonic base excitation produced by hydrodynamic force imposed on the propeller blades interacting with the hull and by other sources. Vibration design aspects for shipboard pipework are often ignored, which may cause catastrophic fatigue failures and, consequently, leakage and spillage in the sea environment. Without dedicated design codes, the integrity of shipboard equipment against this environment loading can be ensured by testing as per test standard MIL-STD-167-1A (2005). However, in many cases, testing is not feasible and economically viable. Hence, this study develops an FE-based vibration analysis methodology based on MIL-STD-167-1A, which can be a valuable tool to optimize the testing requirement without compromising the integrity of these piping systems. The simulated model dynamic properties are validated with experimental modal testing and Harmonic response analysis result confirm that a mitigating solution option can be verified by a FE based vibration analysis to mitigate the vibration problem. [ABSTRACT FROM AUTHOR]

The retreat of mountain glaciers inevitably leads to an increase in the number of outburst moraine lakes. One of the possible mechanisms of moraine dam outburst along with overflow over the crest is the formation of a filtration channel in the body of the moraine dam (piping). An algorithm for calculating the outburst flood hydrograph, describing the development of a filtration channel in the body of a moraine dam and the subsequent formation of water overflow when the soil above the channel collapses, is proposed in this paper. Verification of proposed methodology was carried out on the basis of experimental data and published data of real outbursts. Satisfactory results verifying this methodology made it possible to use the proposed methodology for the calculation of the hydrograph of the outburst of Lake Bashkara in the Elbrus region, which occurred on 1 September 2017. It is shown that the simulation results are quantitatively comparable with the estimates obtained from field data: the time of water discharge through the channel was 16 min, the period of the outburst wave passage was 40 min, and the maximum discharge was 636 m3/s. Thus, the possibility of applying the proposed methodology for calculating the destruction of natural moraine dams has been demonstrated. [ABSTRACT FROM AUTHOR]

Construction of earth fill dams offers a cost-effective solution for various purposes. However, their susceptibility to internal soil erosion, known as piping, poses a significant risk of structural failure and resultant loss of life and property. Soil stabilization emerges as a practical technique to fortify these dams against such threats. This study investigated the impact of lime on the internal erosion properties of clay soils, focusing on CH and ML soil types. Specimens of different lime content were prepared and remolded at 95% relative compaction and optimum moisture content. Hole Erosion tests at varying lime concentrations and curing durations were adapted to conduct the investigation. This investigation aims to optimize lime content and curing time for cohesive soil stabilization against internal erosion. Findings revealed that 2% and 5% of quicklime, by dry weight of the soil, effectively stabilized CH and ML soils, respectively, against internal erosion, with a two-day curing period proving optimal. Furthermore, the addition of lime significantly enhanced erosion rate index and critical shear strength in clay soil, underscoring its efficacy in soil stabilization efforts. [ABSTRACT FROM AUTHOR]

The objective of reliability-based design optimization (RBDO) is to minimize the optimization objective while satisfying the corresponding reliability requirements. However, the nested loop characteristic reduces the efficiency of RBDO algorithm, which hinders their application to high-dimensional engineering problems. To address these issues, this paper proposes an efficient decoupled RBDO method combining high dimensional model representation (HDMR) and the weight-point estimation method (WPEM). First, we decouple the RBDO model using HDMR and WPEM. Second, Lagrange interpolation is used to approximate a univariate function. Finally, based on the results of the first two steps, the original nested loop reliability optimization model is completely transformed into a deterministic design optimization model that can be solved by a series of mature constrained optimization methods without any additional calculations. Two numerical examples of a planar 10-bar structure and an aviation hydraulic piping system with 28 design variables are analyzed to illustrate the performance and practicability of the proposed method. [ABSTRACT FROM AUTHOR]

Ground fissures are linear or curvilinear cracks that are common in the Main Ethiopian Rift, which is part of the East African Rift System. They are a unique type of geohazard affecting roads and railway in many parts of the rift valley. The vicinity of Lake Ziway is underlain by lacustrine, pyroclastic, and/or volcaniclastic sediments that are cut by numerous ground fissures, which run for 2-3 km with up to 1-3-m-wide openings. Plausible causes of ground fissure events, as described in previous studies, include extensional movement due to active rift tectonics, hydro-compaction, and piping. However, the exact mechanism of their evolution is poorly understood. Based on field observations and sediment characterization, we propose a strong case for the role played by internal erosion or piping of pumice deposits in the development of ground fissures. Internal erosion causes the formation of subsurface conduits, which grow in size and eventually collapse, forming ground fissures. Typical sediment-erosion-related geomorphologic features such as disappearing streams, sinkholes, blind gullies, and piping mounds have been observed. These features indicate the presence of a network of pipes that connect the groundwater with surface water in a manner very similar to karst hydrology. Pumice deposits in the study area are found to be the most susceptible to internal erosion leading to ground fissuring due to their bimodal grain size distribution and ultralow density (average specific gravity = 0.6). [ABSTRACT FROM AUTHOR]

In this study, the influence of a vertical load on the deformation of a suspended plastic cutoff wall and the evolution of the piping of a dike foundation were studied through model tests and numerical analysis methods. The results of the numerical analysis were in good agreement with those of the model tests. Under vertical load and seepage force, the suspended plastic cutoff wall has well co-deformation with soil, and the mud permeable zone plays the role of "bridge"; the vertical load can increase the critical hydraulic gradient and failure hydraulic gradient and the corresponding upstream waterhead of dike foundation, and the influence of failure hydraulic gradient is greater than that of critical hydraulic gradient. In addition, the numerical analysis method obtains the distribution and variation in the hydraulic gradient along the piping channel from the pre-set orifice to the inlet, which provides reliable data support for the analysis of the evolution mechanism of dike foundation piping. The study also proves that the mud penetration belt plays a synergistic and auxiliary role in the prevention of dike foundation piping by the suspended cutoff wall, which provides strong support for further understanding of the mechanism of preventing dike foundation piping by the cutoff wall. [ABSTRACT FROM AUTHOR]

A new nondestructive inspection method, the magnetic hammer test (MHT), which uses a compact and highly sensitive tunnel magnetoresistance (TMR) sensor, is proposed. This method complements the magnetic flux leakage method and eliminates the issues of the hammer test. It can therefore detect weak magnetic fields generated by the natural vibration of a pipe with a high signal-to-noise ratio. In this study, several steel pipes with different wall thicknesses were measured using a TMR sensor to demonstrate the superiority of MHT. The results of the measurement show that wall thickness can be evaluated with the accuracy of several tens of microns from the change in the natural vibration frequency of the specimen pipe. The pipes were also inspected underwater using a waterproofed TMR sensor, which demonstrated an accuracy of less than 100 μm. The validity of these results was by simulating the shielding of magnetic fields and vibration of the pipes with the finite element method (FEM) analysis. The proposed noncontact, fast, and accurate method for thickness testing of long-distance pipes will contribute to unmanned, manpower-saving nondestructive testing (NDT) in the future. [ABSTRACT FROM AUTHOR]

Stormwater management systems rely on an acyclic network structure, making the network more vulnerable to failure. Existing stormwater resilience studies have predominantly focused on hydraulic and hydrological characteristics of the system with no robust frameworks to evaluate the resilience of the stormwater piped network in terms of network connectivity. This paper introduces a new index-based quantitative framework to characterise the resilience of acyclic stormwater network structure using graph theory and resilience theories. This includes an index developed to evaluate the overall independency of a pipe within an acyclic piped network. The framework was applied to various simple network structures, and an existing stormwater network demonstrating the influence of network structure, pipeline connectivity and number of outlets on the network resilience. This framework can be used to test different network layouts and structures in urban design and pipeline renewal projects to maximise the resilience of the structure of stormwater networks. [ABSTRACT FROM AUTHOR]

The origin of highly permeable flow paths in carbonate-siliciclastic rocks, such as large-aperture fractures in aquifers in the Eastern Bohemian Cretaceous Basin (EBCB), is poorly understood. The karst potential was assessed from the rock carbonate content and the degree of disintegration after leaching in HCl. Surprisingly, dissolution of calcite in EBCB usually did not lead to rock disintegration until calcite > 78%. Instead, porosity increased significantly. High-porosity rock is held together by microns-thick secondary silica cement with a foam-like structure and considerable tensile strength. Three types of conduits occur in the EBCB: (i) bedding-parallel conduits associated with calcite-rich layers, (ii) subvertical fracture swarm conduits that develop on damaged zones of fracture swarms, and (iii) conduits formed by dissolution of calcite veins by groundwater flow. These are ghost-rock karst features where calcite is leached from the rock in the first phase and the residue is washed out by conduits under steep hydraulic gradients in the second phase. Very similar features have been described in Minnesota and Wisconsin, USA. Research has shown that fractures with sharp-edged walls that give the impression of an extensional tectonics origin may actually be ghost-rock karst features in which dissolution and piping have played an important role in their enlargement. [ABSTRACT FROM AUTHOR]

Nowadays, thermal comfort is becoming a major problem for people due to increasing global warming and climatic changes, but it can be resolved by the concept of Heating, Ventilation, and Air Conditioning (HVAC) systems. The purpose of HVAC is to provide occupants with a comfort zone so that they can feel comfortable according to their thermal comfort. The core objective of this study is to design and propose an HVAC system as per actual design conditions for the University Auditorium located in Karachi, Pakistan. A direct Expansion (DX – Type) system is installed in the Auditorium that has exceeded the lifespan of twenty years, refrigerant R-22 which is currently being used has been obsolete due to its high GWP (Global Warming Potential) and ODP (Ozone Depletion Potential) values which are 1810 and 0.05 respectively. To achieve the objective of this study, two approaches are employed. Cooling Load Temperature Difference (CLTD) method & Hourly Analysis Program (HAP) software. The cooling load calculated from the CLTD method is 202 kW equivalent to 57.5 Ton of Refrigeration (TR). On the other side, the cooling load calculated from HAP software is 192.8 kW equivalent to 55 TR. By considering the calculated cooling load for the University Auditorium, two different HVAC systems are proposed, based on Water cooled and Air-cooled Vapor Compression Cycle. After this study, engineers will be able to design an HVAC system for any facility as per design conditions. Also, they can propose different cost-effective and energy-efficient HVAC systems for that particular space.

The vibration of piping systems is one of the most important causes of accelerated equipment wear and reduced work efficiency and safety. In this study, an active vibration control method based on a fractional-order proportional–integral–derivative (PID) controller was proposed to suppress pipeline vibration and reduce pipeline damage. First, a mathematical model of the distributed piping system was established using the finite element analysis method, and the characteristics of the distributed piping system were studied effectively. Further, the time-frequency domain parameter identification method was used to realise the system identification of the cross-point vibration transfer function between the brake and sensor, and the particle swarm optimisation algorithm was utilised to further optimise the transfer function parameters to improve the system identification accuracy. Therefore, a fractional-order PID controller was designed using the D-decomposition method, and the optimal controller parameters were obtained. The experimental and numerical simulation results show that the improved system identification algorithm can significantly improve modelling accuracy. In addition, the designed fractional-order PID controller can effectively reduce the system's overshoot, oscillation time, and adjustment time, thereby reducing the vibration response of piping systems. [ABSTRACT FROM AUTHOR]

Given the mounting apprehension surrounding the recurrence of incidents involving accidents and the failure of earthen dams in the past two decades, a significant number of which can be attributed to phenomena such as seepage-induced piping and overtopping, this research was conducted utilizing non-destructive geoelectrical techniques at an earthen dam site. The primary objective was to monitor the stability of the landfill and identify potential abnormal pathways for fluid infiltration. We propose the combined application of electric resistivity tomography and induced polarization methods as indirect, non-invasive mechanisms to evaluate the structural and hydrodynamic stability of the embankment dike and its foundation. This approach complements conventional instrumentation, often referred to as auscultation, which relies on piezometric level analyses, displacement measurements, and visual inspections. A geophysical survey was conducted at an earthen dam in Rio de Janeiro, Brazil. The reservoir was specifically engineered for industrial water storage. During the study period, resistivity and chargeability measurements were systematically conducted in both rainy and dry periods, facilitating the observation of dam slope behavior under diverse climatic conditions. Consequently, we observed increased conductivity values during periods of increased humidity, and decreased chargeability values served as indicators of water saturation within the dam structure. This comprehensive data interpretation proved to be highly efficient, and the proposed methodology holds the potential for application to a wide array of landfill dams, with a particular emphasis on ore tailing dams. [ABSTRACT FROM AUTHOR]

Improving knowledge of existing levees through investigation and monitoring is an important step in evaluating their safety and that of the surrounding area. Nevertheless, these activities are complex due to the considerable levee length and the high spatial variability of soil composing the body and foundation, especially when paleo-rivers are present. In order to investigate the reliability of new advanced techniques proposed for characterizing the soil stratigraphy and the seepage condition within the levee foundation, a new test site was realized along the Adige River in Bolzano Province (Italy). Here, five boreholes, drilled in a 20-m-side square area straddling the embankment, host four different types of monitoring equipment, among which some are Distributed Fiber Optical Sensors (DFOS), here used for detecting the temperature variations along the well. The present paper focuses on the critical analysis of the preliminary results obtained with DFOS and their comparison with data obtained using traditional pressure and temperature probes. The monitoring data collected in the field during the passage of a flood that occurred on 5th August 2021 are used to better understand the hydraulic behavior and the safety conditions of the levee but also to fully assess the reliability and potential of DFOS. [ABSTRACT FROM AUTHOR]

Dike foundation piping is one of the most important reasons for the dangerous situation and even the breach of dikes in Poyang Lake Area. It is of great significance to study and explain the disaster-causing mechanism of dike foundation piping in Poyang Lake Area from the mechanism so as to deal with the dangerous situation of piping and carry out emergency rescue scientifically.In this paper, an organic glass model tank is designed and manufactured, which integrates the functions of pore water pressure signal acquisition, seepage flow observation, erosion soil particle collection, graded constant head control, internal water circulation and so on. Based on the typical dike foundation structure of a dike in Poyang Lake Area, the physical model test of piping is carried out by using the prototype soil of dike foundation, and the whole process of piping occurrence, development and collapse of prototype multi-layer complex dike foundation is completely simulated. Combined with the experimental phenomena, the hydraulic conditions and soil particle erosion rate of the six stages (surface crack development stage, latent layer failure stage, overlying layer failure stage, piping channel upstream stage, embankment foundation failure stage, embankment foundation collapse stage ) in the process of piping occurrence and development are analyzed, and the special embankment foundation failure mechanism of the dike is explained by analyzing the effect of vertical seepage force.The results show that the piping failure in the dike foundation structure in Poyang Lake Area is concentrated in the underlying sand layer. Under the action of osmotic pressure, the overlying weak permeable layer is penetrated by seepage, and the piping channel is formed on the contact surface between the sand layer and the overlying layer, which accelerates the erosion of soil particles and eventually leads to the dike foundation collapse. The loam layer sandwiched in the clay layer in the embankment foundation of a typical dike in the Poyang Lake Area cannot play the role of the transition layer between the strong and weak permeable layers. The law of soil particle erosion is similar to that of the embankment foundation without the transition layer. The growth rate of the cumulative erosion of the soil particles forming the surface piping outlet and the embankment foundation cracking is less than 0.1 g/s; the average overall critical horizontal gradient of the dike foundation where piping occurs is about 0.1. [ABSTRACT FROM AUTHOR]

Pipelines play a pivotal role in transporting large volumes of oil and gas within refineries. However, over time, they are susceptible to deterioration, leading to potential failures. Effective monitoring is imperative to maintain their optimal performance and safety. This research introduces a machine learning (ML) approach to pinpoint failure sources in oil and gas pipelines. Analysing an industrial dataset, we compared six ML models to predict failures in refinery pipelines. Leakage sources are predicted based on three operational parameters: transported fluid, temperature, and pressure. The models are evaluated and compared in terms of precision, recall, F1-score, accuracy, and the ROC-AUC. Remarkably, the XGBoost classifier exhibited a 99.7% accuracy, outperforming other algorithms in predicting the failure source. Emphasizing the value of Industry 4.0 solutions, this study underscores the potential of advanced ML in enhancing pipeline monitoring. Such predictions empower operators to pre-empt failures, reinforcing industry safety and sustainability. [ABSTRACT FROM AUTHOR]

Nowadays, thermal comfort is becoming a major problem for people due to increasing global warming and climatic changes, but it can be resolved by the concept of Heating, Ventilation, and Air Conditioning (HVAC) systems. The purpose of HVAC is to provide occupants with a comfort zone so that they can feel comfortable according to their thermal comfort. The core objective of this study is to design and propose an HVAC system as per actual design conditions for the University Auditorium located in Karachi, Pakistan. A direct Expansion (DX - Type) system is installed in the Auditorium that has exceeded the lifespan of twenty years, refrigerant R-22 which is currently being used has been obsolete due to its high GWP (Global Warming Potential) and ODP (Ozone Depletion Potential) values which are 1810 and 0.05 respectively. To achieve the objective of this study, two approaches are employed. Cooling Load Temperature Difference (CLTD) method & Hourly Analysis Program (HAP) software. The cooling load calculated from the CLTD method is 202 kW equivalent to 57.5 Ton of Refrigeration (TR). On the other side, the cooling load calculated from HAP software is 192.8 kW equivalent to 55 TR. By considering the calculated cooling load for the University Auditorium, two different HVAC systems are proposed, based on Water cooled and Air-cooled Vapor Compression Cycle. After this study, engineers will be able to design an HVAC system for any facility as per design conditions. Also, they can propose different cost-effective and energy-efficient HVAC systems for that particular space. [ABSTRACT FROM AUTHOR]

Copyright of Jurnal Teknologi dan Rekayasa Sumber Daya Air is the property of Brawijaya University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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In the operation of oil and gas exploration and exploitation, safety is crucial as it is related to asset safety, environmental safety, and human resource safety. Storage tanks play a crucial role in the process of exploring and exploiting crude oil, serving as storage facilities for liquids in large volumes. These storage tanks are susceptible to corrosion as the materials used in their construction are typically made of steel. Uncontrolled corrosion can weaken or destroy parts of the tank system, leading to holes or structural failures that may release stored products into the environment, resulting in material losses and potential fatalities. One method for assessing the viability of pressure equipment such as pressure vessels, storage tanks, and piping systems is Fitness for Service (FFS). FFS is a quantitative engineering evaluation conducted to demonstrate the structural integrity of a component in operation, even if it has experienced damage, defects, or cracks. Guidelines in FFS procedure manuals can be used to make decisions regarding "continued/repair/replacement" to ensure that components experiencing damage or defects can continue to operate for a specified period. The thickness measurements on the storage tank show that the lowest thickness is found in course 4, with a value of 4.32 mm, while the highest thickness is in the roof at 5.60 mm. The highest corrosion rate is detected in the roof with a value of 0.100 mm/year, and from this corrosion rate value, an estimated remaining life of 20 years for storage tank T-10 is obtained. In assessing the feasibility or Fitness for Services of the storage tank, it still meets the criteria specified by API 579. [ABSTRACT FROM AUTHOR]

The piping system connected with the shipboard equipment may be subjected to excessive vibration due to harmonic base excitation produced by hydrodynamic force imposed on the propeller blades interacting with the hull and by other sources. Vibration design aspects for shipboard pipework are often ignored, which may cause catastrophic fatigue failures and, consequently, leakage and spillage in the sea environment. Without dedicated design codes, the integrity of shipboard equipment against this environment loading can be ensured by testing as per test standard MIL-STD-167-1A (2005). However, in many cases, testing is not feasible and economically viable. Hence, this study develops an FE-based vibration analysis methodology based on MIL-STD-167-1A, which can be a valuable tool to optimize the testing requirement without compromising the integrity of these piping systems. The simulated model dynamic properties are validated with experimental modal testing and Harmonic response analysis result confirm that a mitigating solution option can be verified by a FE based vibration analysis to mitigate the vibration problem.

The measurement of the permeable water pressure, the flow rate of leakage and drainage from the beginning of the construction of the rockfill dam are the most important characteristics needed in analysis these dams. Failure to control the above parameters can cause the waste of water stored in the reservoir, threaten the safety of the dam, and also reduce the stability of the dam through piping or liquefaction. Rockfil1 dams are used to prevent seepage, store water, control floods and delay floods. The problem of leakage should be controlled and limited in such a way as to prevent the creation of adverse effects such as: loss of water stored behind the earthen structure, creation of pore pressure in the porous medium, reduction of the effective stress between soil particles and, as a result, reduction prevent its shear resistance. In many cases, rockfill dam meets the needs of the project, because gravel is far more stable than soil and its ability to be washed is less. The slopes of the gravel dam body are steeper than many other soils, which saves money. In the present research, gravel materials were first prepared from the river mines of Khuzestan province to conduct experiments. These materials were used in three sizes with an average diameter of 10, 20 and 30 mm respectively to make the model. In this research, it was tried to study the leakage parameters in the gravel dam by building a physical model. A physical model of a gravel dam was built in a laboratory flume with three gravel samples and three slopes with the aim of investigating and determining the amount of leakage from the dam body. Pore pressure was measured with piezometers installed in the flume body. The results of the research showed that in a constant slope, the flow-field angle increases as the flow depth increases. Also, with the increase of the flow rate and the increase of the diameter of the particles, the depth of the outlet flow is reduced and these changes are not clear at low flow rates, but are clearly visible at high flow rates. In constant diameter and flow rate, with the increase of the slope of the model, the depth of the outlet flow decreases, and in the constant flow rate, with the increase of the ratio (Bc/H), the value of the outlet height of the flow decreases. Based on the experiments, the following results are presented. In the ratio of Bc/H = 1, with the increase of upstream depth, the depth of outflow has increased. Considering that the depth of the outlet flow downstream can be determined using the concept of the flow-field angle, it can be said that the depth of the outlet flow increases with the increase of the flow-field angle. In the ratio Bc/H=2, with the increase in the width of the model, the depth of the outlet flow has decreased compared to Bc/H=1. In addition, it can be concluded that in a constant slope, with the increase in flow depth, flow-field angle increases. Also, with the increase in the diameter of the particles, the depth of the outflow decreases. These changes are not clear at low flow rates but are clearly visible at high flow rates.

The aging analysis of nuclear power plant components and materials is crucial for the power plant’s safety, and for its upgradation and life extension. The health monitoring of power plant materials, such as steel, is mostly done by employing conventional non-destructive evaluation (NDE) techniques. Considering the limitations associated with conventional NDE techniques, thermoelectric power based NDE (TNDE) is being explored. This paper presents the first ever development and successful demonstration of TNDE in Pakistan. Moreover, the aging analysis of carbon steel grade SA 106B is also being presented for the first time. The extraction-steam pipe samples (new and aged) of SA 106B, from a 46-years-old operating nuclear power plant, are being analyzed and the sensitivity of TNDE to aging induced changes in microstructure is demonstrated. Further, the aged SA 106B is simulated via heat treatment and the equipment is calibrated for its utilization in the nuclear power plant. The correlation between thermoelectric power (TEP) and Vicker hardness (HV) [TEP (µV/oC) = ~2x10-5 Hardness (HV) + 0.008] has been analyzed. It is revealed that the technique has the potential to analyze mechanical properties of aged extraction steam piping without cutting and taking the samples to the laboratory.

While several theoretical and experimental studies for cracks in piping exist, most pertain to pipelines, equipment, or fittings under pressure conditions or under stress corrosion conditions at welding. Element finite Method models have occasionally supplemented experimental methods, to investigate such operational fails. In this approach we explore technical options to comprehensively understand crack propagations, by first, evaluating the Stress Intensity Factor (KI) using ANSYS Parametric design language then, comparing with the Displacement Correlation Technique, for an elliptical base gas piping (20″APL Gr. B) suffering a longitudinal welding-induced crack, under a compression of 1.86 MPa. The KIvalue for an Electric Resistance Welding crack was calculated for the two-dimensional plane, for a quarter-length of propagated crack along the elliptical front. The KI value estimates are 0.94x(10)−3 MPam from ANSYS Parametric design language vs. 0.70x(10)−2 MPamfrom DCT the two methods are close less than 1. These results were compared with the theorical stress intensity factor for elliptical cracks by Broek11 Broek, D. (1984). Elementary engineering fracture mehcanics . The Hague: Martinus Nijhoff Publishers. David called elementary engineering fracture mechanics where the values were 0.5x(10)−1 MPam. We found that the proposed FEM method for estimating (KI)is the approach that is closest to the theoretical value.

Piping is a major factor contributing to river embankment breaches, particularly during flood season in small and medium rivers. To reduce the costs of earth rock embankment inspections, avoid the need for human inspectors and enable the quick and widespread detection of piping hazards, a UAV image-acquisition function was introduced in this study. Through the collection and analysis of thermal infrared and visible (TIR & V) images from several piping field simulation experiments, temperature increases, and diffusion centered on the piping point were discovered, so an automatic algorithm for piping identification was developed to capture this phenomenon. To verify the identification capabilities, the automatic identification algorithm was applied to detect potential piping hazards during the 2022 flooding of the Dingjialiu River, Liaoning, China. The algorithm successfully identified all five piping hazard locations, demonstrating its potential for detecting embankment piping. [ABSTRACT FROM AUTHOR]

Numerical simulation of unsteady free surface flows using depth averaged equations that consider the presence of initial discontinuities has been often reported for situations dealing with dam break flow. The usual approach is to assume a sudden removal of the gate at the dam location. Additionally, in order to prevent any kind of dam risk in earthen dams, it is very interesting to include the possibility of a progressive dam breach leading to dam overtopping or dam piping so that predictive hydraulic models benefit the global analysis of the water flow. On the other hand, when considering a realistic large domain with complex topography, a fine spatial discretization is mandatory. Hence, the number of grid cells is usually very large and, therefore, it is necessary to use parallelization techniques for the calculation, with the use of Graphic Processing Units (GPU) being one of the most efficient, due to the leveraging of thousands of processors within a single device. The aim of the present work is to describe an efficient GPU-based 2D shallow water flow solver (RiverFlow2D-GPU) supplied with the formulation of internal boundary conditions to represent dynamic dam failure processes. The results obtained indicate that it is able to develop a transient flow analysis taking into account several scenarios. The efficiency of the model is proven in two complex domains, leading to >76× faster simulations compared with the traditional CPU computation. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of welding sequences on residual stresses and distortions of welded components, using computational thermomechanical model-based finite element analysis (FEA). Residual stresses, a common outcome of welding, can cause material distortions and reduce product quality. We used FEA to simulate transient temperature fields generated during welding and evaluated their impact on the amplitude and distribution of residual stresses, the size of fusion and heat-affected zones, material microstructures, properties and fracture toughness. The study focused on an austenitic pipe butt junction, a commonly welded component in various industries. The identification of optimal welding sequences can minimize residual stresses and distortions, providing valuable insights for the development of efficient welding techniques, improved product quality, and reduced manufacturing costs. [ABSTRACT FROM AUTHOR]

Inverse grading deposits are commonly found in circulation and accumulation areas of high-speed and long-distance landslides. Due to its special structure of large particle size at the top and small at the bottom and strong permeability, the accumulation is highly susceptible to unstable failure. In this study, using a self-designed device, seepage erosion tests were conducted on seven sets of inverse grading soil samples with continuous and discontinuous particle gradation of particle size 0.075-20 mm to investigate the parameter changes and fine particle migration patterns and laws during seepage erosion of inverse grading sand mass. The results show that the fine particle content and nonuniformity coefficient have an important influence on the seepage erosion of the inverse grading soil samples. The higher the fine particle content, the greater the nonuniformity coefficient and the lower the initial seepage coefficient. After the occurrence of cross-layer tube surge particles, the bottom layer of particle loss is the most, and the particle size of 0.075-0.125 mm particle loss ratio is the largest.The seepage capacity of the inverse grading sand mass depends mainly on the content of fine particles at the bottom. The higher the content of fine particles is, the greater the critical hydraulic gradient will be.In continuous graded soil samples, the relationship between the hydraulic gradient is quadratically related to the percolation coefficient.Soil samples with discontinuous particle gradation are stabilized when the content of fine particles exceeds 45%.After tube gushing occurred in the reverse grain sequence accumulation body, the particles show a migration pattern of stripping-precipitation-stripping-precipitation alternately eroded particles in the middle and lower layers. The study has theoretical and practical significance for the formation mechanism and prevention of such disasters.

The retreat of mountain glaciers inevitably leads to an increase in the number of outburst moraine lakes. One of the possible mechanisms of moraine dam outburst along with overflow over the crest is the formation of a filtration channel in the body of the moraine dam (piping). An algorithm for calculating the outburst flood hydrograph, describing the development of a filtration channel in the body of a moraine dam and the subsequent formation of water overflow when the soil above the channel collapses, is proposed in this paper. Verification of proposed methodology was carried out on the basis of experimental data and published data of real outbursts. Satisfactory results verifying this methodology made it possible to use the proposed methodology for the calculation of the hydrograph of the outburst of Lake Bashkara in the Elbrus region, which occurred on 1 September 2017. It is shown that the simulation results are quantitatively comparable with the estimates obtained from field data: the time of water discharge through the channel was 16 min, the period of the outburst wave passage was 40 min, and the maximum discharge was 636 m3/s. Thus, the possibility of applying the proposed methodology for calculating the destruction of natural moraine dams has been demonstrated.